Electrical and Electronics Engineering publications abstract of: 09-2017 sorted by title, page: 2

» A Varying Frequency LPV-Based Control Strategy for Three-Phase Inverters
Abstract:
Grid-connected inverters have drawn a lot of attention in the integration of distributed generation systems and microgrids, as they are an effective interface for renewable and sustainable energy sources. Several strategies, including repetitive and resonant controllers, have been implemented in order to achieve low distortion and high-quality power. However, it has been proved that their performance decreases substantially when the grid frequency varies. This paper proposes a resonant control strategy based on a linear parameter varying (LPV) design, which is able to deal with changes in the network frequency. Controller aim is associated with injecting a clean sinusoidal current to the grid, even in the presence of nonlinear/unbalanced loads and/or grid-voltage distortions. Main emphasis is focused on presenting an applied LPV design procedure that covers plant modeling, controller synthesis, stability analysis, and experimental results that show the feasibility and effectiveness of the proposed scheme.
Autors: Germán Andrés Ramos;René Alexander Soto-Perez;Jenny Alexandra Cifuentes;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 7599 - 7608
Publisher: IEEE
 
» A Versatile Laminar Flow Atmospheric Pressure Plasma Jet Using a Double Coaxial Glass Tube
Abstract:
We report the characteristics of laminar flow atmospheric pressure plasma jets (APPJs) using a double coaxial glass tube. Two gases can be introduced independently into the tube, and the gas and plasma flows form a laminar flow and then interact outside of the glass tube. In the case of helium (He) as an inner gas flow with an outer nitrogen (N2) gas flow, emission lines of nitric oxide, the first negative and second positive system bands of N2 were observed, while only the second positive system band was observed in the case of argon (Ar) as the inner one. Considering the Penning effects of each excited state, the metastable state of He has a higher energy than that of Ar, resulting in energetic nitrogenous productions in the former case. The excited state in the core plasma is one of the important conditions to determine the characteristics of the APPJ produced with a double coaxial glass tube.
Autors: Hayato Ohashi;Kohei Oyama;Tetta Mitani;Kenta Naiki;Tomohiro Nakayama;Hiroaki Ito;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Sep 2017, volume: 45, issue:9, pages: 2481 - 2485
Publisher: IEEE
 
» A Wearable Hip Assist Robot Can Improve Gait Function and Cardiopulmonary Metabolic Efficiency in Elderly Adults
Abstract:
The aims of this paper were to investigate the effectiveness of a newly developed wearable hip assist robot, that uses an active assist algorithm to improve gait function, muscle effort, and cardiopulmonary metabolic efficiency in elderly adults. Thirty elderly adults (15 males/ 15 females) participated in thispaper. The experimental protocol consisted of overground gait at comfortable speed under three different conditions: free gait without robot assistance, robot-assisted gait with zero torque (RAG-Z), and full RAG. Under all conditions, muscle effort was analyzed using a 12-channel surface electromyography system. Spatio-temporal data were collected at 120 Hz using a 3-D motion capture system with six infrared cameras. Metabolic cost parameters were collected as oxygen consumption per unit (ml/min/kg) and aerobic energy expenditure (Kcal/min). In the RAG condition, participants demonstrated improved gait function, decreased muscle effort, and reduced metabolic cost. Although the hip assist robot only provides assistance at the hip joint, our results demonstrated a clear reduction in knee and ankle muscle activity in addition to decreased hip flexor and extensor activity. Our findings suggest that this robot has the potential to improve stabilization of the trunk during walking in elderly adults.
Autors: Hwang-Jae Lee;Suhyun Lee;Won Hyuk Chang;Keehong Seo;Youngbo Shim;Byung-Ok Choi;Gyu-Ha Ryu;Yun-Hee Kim;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Sep 2017, volume: 25, issue:9, pages: 1549 - 1557
Publisher: IEEE
 
» A Wide-Angle Scanning Phased Array With Microstrip Patch Mode Reconfiguration Technique
Abstract:
A method based on the microstrip patch mode and reconfiguration technique is analyzed, studied, and applied to wide-angle scanning phased arrays. First, a summative evaluation of microstrip patch modes available for wide-angle scanning or near endfire has been made. Second, to validate this new method, a multilayer microstrip patch element is established and its resonant modes TM01 and TM20 are excited. Third, a reconfigurable technique is used to reconfigure the above resonant modes and a wide joint 3-dB beam coverage is obtained. Fourth, a prototype of uniform linear phased array with the above reconfigurable elements is proposed. The prototype operates at 5.8 GHz and its main-beam direction can scan from −75° to +75° in the elevation plane with a gain fluctuation less than ±1 dB. Finally, in order to reduce the sidelobe levels, a hybrid particle swarm optimization algorithm is used to optimize the excitation amplitudes and phases. The measured results show an excellent wide-angle scanning performance, which validates the effectiveness of the proposed method.
Autors: Xiao Ding;You-Feng Cheng;Wei Shao;Bing-Zhong Wang;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2017, volume: 65, issue:9, pages: 4548 - 4555
Publisher: IEEE
 
» A Wideband Low Cost and Optically Transparent Water Patch Antenna With Omnidirectional Conical Beam Radiation Patterns
Abstract:
A novel kind of optically transparent, low cost and wideband water patch antenna is demonstrated and analyzed. A significant feature of the proposed linearly polarized antenna is that both the patch and the ground plane are made of water. Thus, the whole structure becomes optically transparent except the small central feeding probe. The main radiators are made of water, which is available everywhere, low in cost and easy to be fabricated compared with other transparent materials. Results show that a wide impedance bandwidth of 35% for dB, a gain up to 4 dBi and symmetric omnidirectional conical beam radiation patterns with small cross-polarizations can be obtained. Due to the low cost and remarkable radiation performances, this novel transparent patch antenna is believed to have many promising applications in the future transparent electronics designs and flexible electronics.
Autors: Jie Sun;Kwai-Man Luk;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2017, volume: 65, issue:9, pages: 4478 - 4485
Publisher: IEEE
 
» A Wideband Square-Slot Antenna Array With Superstrate and Electromagnetic Bandgap Reflector for 60-GHz Applications
Abstract:
A antenna array with wideband and high gain is proposed for 60-GHz applications. The operating bandwidth is from 57 to 66 GHz. A superstrate above and an electromagnetic bandgap reflector below the array structure increase peak gain and decrease backward radiation, respectively. This paper elaborates the design guidelines. The slot stubs are designed appropriately to increase the bandwidth of square-slot antenna and maintain the radiation pattern. The simulated and measured impedance bandwidth ( dB) are 28.8% (52.6–69.9 GHz) and 23.2% (52.6–66.5 GHz), respectively. The peak antenna gain ranging from 57 to 66 GHz is simulated to be 14.2–12.4 dBi, while the measured peak gain at 57, 60, 63, and 66 GHz are 13.6, 13.4, 12.6, and 11.3 dBi, respectively. The above results can satisfy requirement of many commercial applications.
Autors: Chih-Yu Cheng;Jiun-Peng Chen;Hsin-Lung Su;Ken-Huang Lin;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2017, volume: 65, issue:9, pages: 4618 - 4625
Publisher: IEEE
 
» A Writing-Across-the-Curriculum Faculty Development Program: An Experience Report
Abstract:
This case study reports on the experiences of designing and assessing the effectiveness of a faculty development program on writing across the curriculum (WAC). The report focuses on the question: What are the key components of an effective faculty development program to integrate WAC into engineering and scientific courses taught by faculty in those disciplines? Situating the case: Two main models of WAC implementation exist: direct instruction, which uses writing specialists to deliver instruction to engineering and science students, and the department-centered model, which instructs faculty in engineering and scientific disciplines to teach writing as part of technical courses. How the case was studied: A report of the experiences of the authors and the feedback from the participants. About the case: The workshop was aimed at teachers in various disciplines and covered these main topics: fundamentals of writing theory and pedagogy, writing assignment design and assessment, and situating writing assignments in courses across the disciplinary curriculum. It took place over 10 weeks during a 15-week semester and included large- and small-group meetings, consultations with the members of the university WAC program, and peer review of writing assignment drafts. Conclusions, limitations, and suggestions for future research: Key challenges in developing the workshop included designing ways to bridge the conceptual gap between the participants' and WAC instructors' understanding of the role of writing in disciplinary courses, limited time available to the participants, and scheduling challenges. The workshop was given seven times. Most of the faculty participants (90%) generally found it to be very effective or effective. Studies of workshops with larger populations of trainees are suggested.
Autors: Pavel Zemliansky;Landon Berry;
Appeared in: IEEE Transactions on Professional Communication
Publication date: Sep 2017, volume: 60, issue:3, pages: 306 - 316
Publisher: IEEE
 
» A Zero-Current Opening Circuit for Inductive Pulsed-Power Supply Based on High-Temperature Superconducting Pulsed-Power Transformer
Abstract:
The opening switch is one of the critical technologies in the development of inductive pulsed-power supply. The power requirement is very high when the opening switch is desired to commutate a large current. This paper presents a zero-current opening circuit for inductive pulsed-power supply based on a high-temperature superconducting pulsed-power transformer. First, there are two types of current flowing through the opening switch, one comes from the secondary side of the pulse transformer, and the other one comes from superconducting energy storage inductance. The orientation of the two current is opposite. Then, when the current flowing through the opening switch closes to zero, the switch is opened and this restrains the over-voltage pulse of the opening switch. The simulation results indicate that this zero-current opening circuit is feasible and has potential applications for high-energy systems in the future electromagnetic launcher.
Autors: Xiaotong Zhang;Zhenmei Li;Haitao Li;Cunshan Zhang;Shucun Liu;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Sep 2017, volume: 45, issue:9, pages: 2536 - 2540
Publisher: IEEE
 
» About Chairing the IEEE RAS Women in Engineering Committee [Women in Engineering]
Abstract:
Autors: Laura Margheri;
Appeared in: IEEE Robotics & Automation Magazine
Publication date: Sep 2017, volume: 24, issue:3, pages: 20 - 21
Publisher: IEEE
 
» Accurate and Fast Demodulation Algorithm for Multipeak FBG Reflection Spectra Using a Combination of Cross Correlation and Hilbert Transformation
Abstract:
We demonstrate a combined cross correlation and Hilbert transform-based demodulation algorithm for tracking the wavelength shifts of fiber Bragg gratings (FBGs) having a multiple peak reflection spectrum. We show how the Hilbert transform can be employed to convert the task of locating the maximum of the wavelength profile to the one of finding the zero crossing. We observed higher accuracy and fast response compared to other well-known demodulation algorithms such as the centroid detection algorithm and the cross-correlation algorithm. In addition, we show that the multipeak reflection spectrum that occurs in multimode fibers does not greatly affect the algorithm results. Finally, we experimentally recover axial strain measurements using a multipeak reflection spectrum of an FBG inscribed in a multimode gradient index CYTOP fiber using the newly developed algorithm.
Autors: Antreas Theodosiou;Michael Komodromos;Kyriacos Kalli;
Appeared in: Journal of Lightwave Technology
Publication date: Sep 2017, volume: 35, issue:18, pages: 3956 - 3962
Publisher: IEEE
 
» Accurate Heart Rate Monitoring During Physical Exercises Using PPG
Abstract:
Objective: The challenging task of heart rate (HR) estimation from the photoplethysmographic (PPG) signal, during intensive physical exercises, is tackled in this paper. Methods: The study presents a detailed analysis of a novel algorithm (WFPV) that exploits a Wiener filter to attenuate the motion artifacts, a phase vocoder to refine the HR estimate and user-adaptive post-processing to track the subject physiology. Additionally, an offline version of the HR estimation algorithm that uses Viterbi decoding is designed for scenarios that do not require online HR monitoring (WFPV+VD). The performance of the HR estimation systems is rigorously compared with existing algorithms on the publically available database of 23 PPG recordings. Results: On the whole dataset of 23 PPG recordings, the algorithms result in average absolute errors of 1.97 and 1.37 BPM in the online and offline modes, respectively. On the test dataset of 10 PPG recordings which were most corrupted with motion artifacts, WFPV has an error of 2.95 BPM on its own and 2.32 BPM in an ensemble with two existing algorithms. Conclusion: The error rate is significantly reduced when compared with the state-of-the art PPG-based HR estimation methods. Significance: The proposed system is shown to be accurate in the presence of strong motion artifacts and in contrast to existing alternatives has very few free parameters to tune. The algorithm has a low computational cost and can be used for fitness tracking and health monitoring in wearable devices. The MATLAB implementation of the algorithm is provided online.
Autors: Andriy Temko;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Sep 2017, volume: 64, issue:9, pages: 2016 - 2024
Publisher: IEEE
 
» Accurate Modeling of Thermal Resistance for On-Wafer SiGe HBTs Using Average Thermal Conductivity
Abstract:
An accurate analytic model is proposed for estimating the junction temperature and thermal resistance in silicon–germanium heterojunction bipolar transistors (SiGe HBTs) including the back-end-of-line (BEOL) metal layers. The model uses an average value of thermal conductivity in order to include the temperature dependence of thermal resistance. The parameters corresponding to the thermal conductivity and the BEOL thermal resistance used in the model are extracted following a recently reported methodology. The proposed model is scalable in nature and verification with experimental data shows an excellent accuracy across different emitter geometries of SiGe HBTs fabricated in STMicroelectronics B9MW technology. Compact model simulations show that the proposed model simulates around 23% faster compared with an existing state-of-the-art iterative method.
Autors: Suresh Balanethiram;Anjan Chakravorty;Rosario D’Esposito;Sebastien Fregonese;Didier Céli;Thomas Zimmer;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3955 - 3960
Publisher: IEEE
 
» Achievable Rate and Energy Efficiency of Hybrid and Digital Beamforming Receivers With Low Resolution ADC
Abstract:
For 5G, it will be important to leverage the available millimeter wave spectrum. To achieve an approximately omnidirectional coverage with a similar effective antenna aperture compared with the state-of-the-art cellular systems, an antenna array is required at both the mobile and base stations. Due to the large bandwidth, the analog front-end of the receiver with a large number of antennas becomes especially power hungry. Two main solutions exist to reduce the power consumption: Hybrid BeamForming (HBF) and Digital BeamForming (DBF) with low resolution Analog to Digital Converters (ADCs). An HBF system can also be combined with low resolution ADCs. This paper compares the spectral and energy efficiency based on the RF-frontend configuration. A channel with multipath propagation is used. In contrast to previous publication, we take the spatial correlation of the quantization noise into account. We show that the low resolution ADC DBF is robust to small Automatic Gain Control (AGC) imperfections. We showed that in the low SNR regime, the performance of DBF even with 1–2 bit resolution outperforms HBF. If we consider the relationship of spectral and energy efficiency, DBF with 3–5 bit resolution achieves the best ratio of spectral efficiency per power consumption of the RF receiver frontend over a wide SNR range. The power consumption model is based on components reported in the literature.
Autors: Kilian Roth;Josef A. Nossek;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Sep 2017, volume: 35, issue:9, pages: 2056 - 2068
Publisher: IEEE
 
» Achievable Rates of Space-Division Multiplexed Submarine Links Subject to Nonlinearities and Power Feed Constraints
Abstract:
We study the achievable rates of submarine fiber systems in the high-dimensional design space of variables including span length, launch power, number of spatial channels, and power feed current. We identify the regimes in which nonlinearities or power feed equipment constraints become dominant, and demonstrate that optimized system design evolves toward the linear regime as the system scales to a high number of spatial channels. We calculate the bit rate achievable by uniform and probabilistically shaped M-ary Quadrature Amplitude Modulation constellations to identify potential capacity-achieving implementations.
Autors: Omar D. Domingues;Darli A. A. Mello;Reginaldo da Silva;Sercan Ö. Arık;Joseph M. Kahn;
Appeared in: Journal of Lightwave Technology
Publication date: Sep 2017, volume: 35, issue:18, pages: 4004 - 4010
Publisher: IEEE
 
» Achieving Ultra Reliable Communication in 5G Networks: A Dependability Perspective Availability Analysis in the Space Domain
Abstract:
As part of the 5G communication paradigm, ultra reliable communication (URC) is envisaged as an important technology pillar for providing anywhere and anytime services to end users. While most existing studies on reliable communication do not investigate this problem from a dependability theory perspective, those dependability-based studies tend to define reliability merely in the time domain. In this letter, we advocate extending the concept of URC from the dependability perspective also in the space domain. We initiate definitions on cell availability and system availability. The availability and the probability of providing a guaranteed level of availability in a network are analyzed both/either cell-wise and/or system-wise. Poisson point process and Voronoi tessellation are adopted to model the spatial characteristics of cell deployment in both homogeneous and heterogeneous networks.
Autors: H. V. Kalpanie Mendis;Frank Y. Li;
Appeared in: IEEE Communications Letters
Publication date: Sep 2017, volume: 21, issue:9, pages: 2057 - 2060
Publisher: IEEE
 
» Acoustic Wave Filter Technology–A Review
Abstract:
Today, acoustic filters are the filter technology to meet the requirements with respect to performance dictated by the cellular phone standards and their form factor. Around two billion cellular phones are sold every year, and smart phones are of a very high percentage of approximately two-thirds. Smart phones require a very high number of filter functions ranging from the low double-digit range up to almost triple digit numbers in the near future. In the frequency range up to 1 GHz, surface acoustic wave (SAW) filters are almost exclusively employed, while in the higher frequency range, bulk acoustic wave (BAW) and SAW filters are competing for their shares. Prerequisites for the success of acoustic filters were the availability of high-quality substrates, advanced and highly reproducible fabrication technologies, optimum filter techniques, precise simulation software, and advanced design tools that allow the fast and efficient design according to customer specifications. This paper will try to focus on innovations leading to high volume applications of intermediate frequency (IF) and radio frequency (RF) acoustic filters, e.g., TV IF filters, IF filters for cellular phones, and SAW/BAW RF filters for the RF front-end of cellular phones.
Autors: Clemens C. W. Ruppel;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Sep 2017, volume: 64, issue:9, pages: 1390 - 1400
Publisher: IEEE
 
» ACStor: Optimizing Access Performance of Virtual Disk Images in Clouds
Abstract:
In virtualized data centers, virtual disk images (VDIs) serve as the containers in virtual environment, so their access performance is critical for the overall system performance. Some distributed VDI chunk storage systems have been proposed in order to alleviate the I/O bottleneck for VM management. As the system scales up to a large number of running VMs, however, the overall network traffic would become unbalanced with hot spots on some VMs inevitably, leading to I/O performance degradation when accessing the VMs. In this paper, we propose an adaptive and collaborative VDI storage system (ACStor) to resolve the above performance issue. In comparison with the existing research, our solution is able to dynamically balance the traffic workloads in accessing VDI chunks, based on the run-time network state. Specifically, compute nodes with lightly loaded traffic will be adaptively assigned more chunk access requests from remote VMs and vice versa, which can effectively eliminate the above problem and thus improves the I/O performance of VMs. We implement a prototype based on our ACStor design, and evaluate it by various benchmarks on a real cluster with 32 nodes and a simulated platform with 256 nodes. Experiments show that under different network traffic patterns of data centers, our solution achieves up to performance gain on VM booting time and VM's I/O throughput, in comparison with the other state-of-the-art approaches.
Autors: Song Wu;Yihong Wang;Wei Luo;Sheng Di;Haibao Chen;Xiaolin Xu;Ran Zheng;Hai Jin;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Sep 2017, volume: 28, issue:9, pages: 2414 - 2427
Publisher: IEEE
 
» Adaptation of Mode Filtering Technique in 4G-LTE Hybrid RoMMF-FSO for Last-Mile Access Network
Abstract:
This paper demonstrates a hybrid radio over multimode fibre and free space optics (RoMMF-FSO) system that can be used to extend the transmission range of the fourth generation long-term evolution (4G-LTE) signal in access networks. A single mode filtering technique (SMFT) is used to enhance 4G-LTE performance. The proposed scheme is evaluated in terms of the system transfer function, laser beam profile, and error vector magnitude (EVM). We show that using SMFT increases the RoMMF-FSO system bandwidth by 2 GHz and improves the received optical power by 13.6 dB. Moreover, the proposed system enhances the EVM by 4%. The measured results show that by using a 1 km MMF instead of a 1 km SMF will marginally increase the measured EVM from ~6.6% to ~7% with a 0.2 dB power penalty with respect to the LTE EVM limit of 12.5% as is specified for 16-quadrature amplitude modulation. The proposed system is validated practically under atmospheric turbulence conditions to mimic the outdoor environment. Measured EVM results are verified theoretically through transmitting LTE signals with turbulent using log-normal model. We also show that for a FSO link span of 500 m to meet the EVM target of 12.5% the SNR power penalties are ~2 dB and ~11 dB for Rytov variance of 1.2 × 10-4 and 0.1, respectively, compared with no turbulence.
Autors: Hassan K. Al-Musawi;Tamas Cseh;Jan Bohata;Wai Pang Ng;Zabih Ghassemlooy;Stanislav Zvanovec;Eszter Udvary;Petr Pesek;
Appeared in: Journal of Lightwave Technology
Publication date: Sep 2017, volume: 35, issue:17, pages: 3758 - 3764
Publisher: IEEE
 
» Adapting Rate and Power for Maximizing Secrecy Energy Efficiency
Abstract:
We present the optimum rate and power adaptation rule that maximizes the average secrecy energy efficiency (SEE) subject to an average transmission power constraint. The SEE is defined as the outage secrecy capacity, the largest secrecy rate, such that the outage probability is less than a certain value, divided by the total power consumption (bits per joule). We characterize the SEE gain provided by varying the rate and/or the power, and discuss the impact of the number of antennas on the optimum adaptation rule.
Autors: Hien Q. Ta;Sang Wu Kim;
Appeared in: IEEE Communications Letters
Publication date: Sep 2017, volume: 21, issue:9, pages: 2049 - 2052
Publisher: IEEE
 
» Adapting Remote Sensing to New Domain With ELM Parameter Transfer
Abstract:
It is time consuming to annotate unlabeled remote sensing images. One strategy is taking the labeled remote sensing images from another domain as training samples, and the target remote sensing labels are predicted by supervised classification. However, this may lead to negative transfer due to the distribution difference between the two domains. To address this issue, we propose a novel domain adaptation method through transferring the parameters of extreme learning machine (ELM). The core of this method is learning a transformation to map the target ELM parameters to the source, making the classifier parameters of the target domain maximally aligned with the source. Our method has several advantages which was previously unavailable within a single method: multiclass adaptation through parameter transferring, learning the final classifier and transformation simultaneously, and avoiding negative transfer. We perform experiments on three data sets that indicate improved accuracy and computational advantages compared to baseline approaches.
Autors: Suhui Xu;Xiaodong Mu;Dong Chai;Shuyang Wang;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Sep 2017, volume: 14, issue:9, pages: 1618 - 1622
Publisher: IEEE
 
» Adaptive Appearance Modeling With Point-to-Set Metric Learning for Visual Tracking
Abstract:
In visual tracking, developing an efficient appearance model is a challenging task due to the influence of various factors, such as illumination variation, occlusion, background clutter, and so on. Existing tracking algorithms use appearance samples from previous frames to form a template set upon which target appearance models are built. However, these appearance models are data-dependent, so they may be corrupted by significant appearance variation. It is difficult to update the templates in challenging environments. In this paper, we propose a robust visual tracking algorithm with an adaptive appearance model using a point-to-set metric learning technique. To do this, we first model a target representation using a set of target templates and a regularized affine hull (RAH) spanned by the target templates. Then, we learn a point-to-set distance metric, which is incorporated into the optimization process to obtain an adaptive target representation. The RAH model covers unseen target appearances by affine combinations of the target templates. Based on the proposed target appearance model, we design an effective template update scheme by adjusting the weights of the target templates. Experimental results on challenging video sequences with comparisons to several state-of-the-art tracking algorithms demonstrate the effectiveness and robustness of the proposed tracking algorithm.
Autors: Jun Wang;Yuanyun Wang;Hanzi Wang;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Sep 2017, volume: 27, issue:9, pages: 1987 - 2000
Publisher: IEEE
 
» Adaptive Clutter Demodulation for Non-Contrast Ultrasound Perfusion Imaging
Abstract:
Conventional Doppler ultrasound is useful for visualizing fast blood flow in large resolvable vessels. However, frame rate and tissue clutter caused by movement of the patient or sonographer make visualizing slow flow with ultrasound difficult. Patient and sonographer motion causes spectral broadening of the clutter signal, which limits ultrasound’s sensitivity to velocities greater than 5–10 mm/s for typical clinical imaging frequencies. To address this, we propose a clutter filtering technique that may increase the sensitivity of Doppler measurements to at least as low as 0.52 mm/s. The proposed technique uses plane wave imaging and an adaptive frequency and amplitude demodulation scheme to decrease the bandwidth of tissue clutter. To test the performance of the adaptive demodulation method at suppressing tissue clutter bandwidths due to sonographer hand motion alone, six volunteer subjects acquired data from a stationary phantom. Additionally, to test in vivo feasibility, arterial occlusion and muscle contraction studies were performed to assess the efficiency of the proposed filter at preserving signals from blood velocities 2 mm/s or greater at a 7.8 MHz center frequency. The hand motion study resulted in initial average bandwidths of 175 Hz (8.60mm/s), which were decreased to 10.5 Hz (0.52 mm/s) at −60 dB using our approach. The in vivo power Doppler studies resulted in 4.73 dB and 4.80 dB dynamic ranges of the blood flow with the proposed filter and 0.15 dB and 0.16 dB dynamic ranges of the blood flow with a conventional 50 Hz high-pass filter for the occlusion and contraction studies, respectively.
Autors: Jaime Tierney;Crystal Coolbaugh;Theodore Towse;Brett Byram;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Sep 2017, volume: 36, issue:9, pages: 1979 - 1991
Publisher: IEEE
 
» Adaptive Consensus of Nonlinear Multi-Agent Systems With Non-Identical Partially Unknown Control Directions and Bounded Modelling Errors
Abstract:
Existing Nussbaum function based results on consensus of multi-agent systems require that the unknown control directions of all the agents should be the same. This note proposes an adaptive method to relax such a requirement to allow non-identical control directions, under the condition that some control directions are known. Technically, a novel idea is proposed to construct a new Nussbaum function, from which a conditional inequality is developed to handle time-varying input gains. Then, the inequality is integrated with adaptive control technique such that the proposed Nussbaum function for each agent is adaptively updated. Moreover, in addition to parametric uncertainties, each agent has non-parametric bounded modelling errors which may include external disturbances and approximation errors of static input nonlinearities. Even in the presence of such uncertainties, the proposed control scheme is still able to ensure the states of all the agents asymptotically reach perfect consensus. Finally, simulation study is performed to show the effectiveness of the proposed approach.
Autors: Ci Chen;Changyun Wen;Zhi Liu;Kan Xie;Yun Zhang;C. L. Philip Chen;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Sep 2017, volume: 62, issue:9, pages: 4654 - 4659
Publisher: IEEE
 
» Adaptive Feedforward Algorithm Without Grid Impedance Estimation for Inverters to Suppress Grid Current Instabilities and Harmonics Due to Grid Impedance and Grid Voltage Distortion
Abstract:
The performance of the grid-connected inverter was affected by the uncertainty of the grid conditions including the background distortion and the grid impedance. Typically, the feedforward of the grid voltage at the point of common coupling (PCC) highly suppressed the grid current harmonics caused by the grid voltage distortion; however, the PCC grid usually had a nonnegligible grid impedance, and the PCC voltage feedforward aroused serious grid current harmonics or instability. This study proposes a novel adaptive algorithm for the PCC voltage feedforward to work well with the varied grid impedance. In the proposal, the band-pass filters at the harmonic frequencies are used to detect the variation of the grid impedance as well as to facilitate the adaptive PCC voltage feedforward. It is not necessary to inject an additional harmonic to estimate the grid impedance. The basic principles as well as the realization and logic of the proposed algorithm are detailed, and some selected waveforms are provided to verify the superior performance. Compared with the typical robust design or adaptive control, the proposed algorithm does not have to sacrifice the dynamic or the harmonics rejection performance, or to use the on or offline grid impedance estimation.
Autors: Jinming Xu;Shaojun Xie;Qiang Qian;Binfeng Zhang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 7574 - 7586
Publisher: IEEE
 
» Adaptive Inter CU Depth Decision for HEVC Using Optimal Selection Model and Encoding Parameters
Abstract:
High efficiency video coding adopts a new hierarchical coding structure, including coding unit (CU), prediction unit (PU), and transform unit to achieve higher coding efficiency than its predecessor H.264/AVC high profile. However, its hierarchical unit partitioning strategy leads to huge computational complexity. In this paper, an adaptive inter CU depth decision algorithm is proposed, which exploits both temporal correlation of CU depth and available encoding parameters. An optimal selection model of CU depth is established to estimate the range of candidate CU depth by exploiting the temporal correlation of CU depth among current CU and temporally co-located CUs. To reduce the accumulated errors in the process of CU depth prediction, the maximum depth of the co-located CUs and the coded block flag (CBF) of the current CU are used. Moreover, PU size and CBF information are also used to decide the maximum depth for the current CU. Experimental results show that the proposed CU depth decision approach reduces 56.3% and 51.5% average encoding time, and the Bjontegaard delta bit rate increases only 1.3% and 1.1% for various test sequences under the random access and the low delay B conditions, respectively.
Autors: Yue Li;Gaobo Yang;Yapei Zhu;Xiangling Ding;Xingming Sun;
Appeared in: IEEE Transactions on Broadcasting
Publication date: Sep 2017, volume: 63, issue:3, pages: 535 - 546
Publisher: IEEE
 
» Adaptive Robust Transmission Expansion Planning Using Linear Decision Rules
Abstract:
This paper presents a novel model for two-stage adaptive robust transmission expansion planning (AR-TEP) problem considering the uncertainty of future load demand and future wind power production. Linear decision rules (LDRs) are utilized to reformulate the AR-TEP model as a tractable mixed-integer linear programming problem, which can be directly solved by off-the-shelf optimization packages. The proposed LDR-based AR-TEP model is illustrated using the Garver 6-bus test system, the IEEE 24-bus reliability test system, and a 236-bus test system under different conditions and compared with a decomposition-based AR-TEP model that uses primal cutting planes. Also, the robustness of the expansion plans obtained from these two AR-TEP models is evaluated by carrying out an ex-post out-of-sample analysis for different values of the budget of uncertainty. Simulation results demonstrate the effectiveness of the proposed LDR-based AR-TEP model.
Autors: Shahab Dehghan;Nima Amjady;Antonio J. Conejo;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2017, volume: 32, issue:5, pages: 4024 - 4034
Publisher: IEEE
 
» Adaptive Tuning of Large-Signal Resonant Circuits Using Phase-Switched Fractional Capacitance
Abstract:
Inductively coupled systems used in applications such as RFID and wireless power often require high factor resonant transmitters to maximize the magnetic field and achieve high overall efficiency. However, these are sensitive to environmental detuning as well as component tolerances. Existing methods for accurate tuning require search algorithms, usually requiring the suspension of normal operation in order to calibrate the resonant inductor–capacitor circuit, thus reducing power throughput and increasing system complexity. We describe here how zero-voltage switched fractional capacitance techniques may be used to achieve continuous and real-time adaptive tuning of large-signal resonant inductor–capacitor circuits. Minimal additional circuitry is required and tuning is maintained without disrupting normal operation. Many variants are possible for the implementation of the system, and some tradeoffs relating to the available tuning range and operating voltages are analyzed for two alternative topologies. Experimental results are presented for a 125-kHz demonstration system.
Autors: W. Redman-White;H. Kennedy;R. Bodnar;T. Lee;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Sep 2017, volume: 64, issue:9, pages: 1072 - 1076
Publisher: IEEE
 
» Adaptive-Robust Time-Delay Control for a Class of Uncertain Euler–Lagrange Systems
Abstract:
This paper proposes a new adaptive-robust control (ARC) strategy for a tracking control problem of a class of uncertain Euler–Lagrange systems. The proposed adaptive-robust time-delay control (ARTDC) amalgamates the ARC strategy with the time-delay control (TDC). It comprises three parts: a time-delay estimation part, a desired dynamics injection part, and an adaptive-robust part. The main feature of the proposed ARTDC is that it does not involve any threshold value in its adaptive law; thus, it allows the switching gain to increase or decrease whenever the error trajectories move away or close to the switching surface, respectively. Thus, compared with the existing ARC schemes, ARTDC is able to alleviate the over- and underestimation problems of the switching gain. Moreover, the stability analysis of ARTDC provides an upper bound for the selection of sampling interval and its relation with controller gains. The proposed ARTDC shows improved tracking performance compared with the TDC and the existing adaptive sliding-mode control in simulations as well as in experiments with a multiple-degree-of-freedom system.
Autors: Spandan Roy;Indra Narayan Kar;Jinoh Lee;Maolin Jin;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 7109 - 7119
Publisher: IEEE
 
» Advanced Synchronizing Systems for Offshore Power Systems: Improving System Reliability and Flexibility
Abstract:
Small power systems, such as those found on offshore platforms, are fragile, yet they must operate reliably for economy and the safety of both personnel and the environment. These systems often include combustion turbine generators for the main process power requirements and black start diesel generators that can supply essential and emergency buses; the diesel generators can also be used to restart the main generation systems in the event of a power-system collapse. The power distribution systems on these offshore platforms have built-in redundancy with multiple circuits to supply critical loads for fault tolerance and operating flexibility. A system to easily and safely synchronize islanded buses via many possible synchronization points can revolutionize the operational flexibility and, therefore, the safety and reliability of the power system. This article reports on advanced synchronizing systems installed on two offshore platforms.
Autors: Michael J. Thompson;Allen Li;Roy Luo;Michael C. Tu;Iris Urdaneta;
Appeared in: IEEE Industry Applications Magazine
Publication date: Sep 2017, volume: 23, issue:5, pages: 60 - 69
Publisher: IEEE
 
» Advances in Signal Processing for GNSSs [From the Guest Editors]
Abstract:
Autors: Pau Closas;Marco Luise;Jose-Angel Avila-Rodriguez;Christopher Hegarty;Jiyun Lee;
Appeared in: IEEE Signal Processing Magazine
Publication date: Sep 2017, volume: 34, issue:5, pages: 12 - 15
Publisher: IEEE
 
» Advertisement Delivery and Display in Vehicular Networks: Using V2V Communications for Targeted Ads
Abstract:
Advertisement (ad) delivery is expected to play a crucial role in future vehicular networks. In this article, we examine how ads can be broadcasted by roadside units (RSUs) as well as vehicles and then displayed to interested users. We describe the ad dissemination process by means of an optimization model that aims to maximize the number of ads that users display within the target area and validity period of the ad. We then solve the optimization problem, obtaining the optimal scheduling strategy that RSUs and vehicles should adopt for ad broadcasting. Our study highlights the important role that vehicle-to-vehicle (V2V) communications will have in ad delivery. Also, it shows how coexisting vehicular and cellular networks can effectively complement each other, with vehicular networks being a very efficient means for pervasive ad dissemination.
Autors: Carla-Fabiana Chiasserini;Francesco Malandrino;Matteo Sereno;
Appeared in: IEEE Vehicular Technology Magazine
Publication date: Sep 2017, volume: 12, issue:3, pages: 65 - 72
Publisher: IEEE
 
» Ahura: A Heuristic-Based Racer for the Open Racing Car Simulator
Abstract:
Designing automatic drivers for car racing is an active field of research in the area of robotics and artificial intelligence. A controller called Ahura (a heuristic-based racer) for the open racing car simulator is proposed in this paper. Ahura includes five modules, namely steer controller, speed controller, opponent manager, dynamic adjuster, and stuck handler. These modules have 23 parameters all together that are tuned using an evolutionary strategy for a particular car to ensure fast and safe drive on different tracks. These tuned parameters are further modified by the dynamic adjuster module during the run according to the width, friction, and dangerous zones of the track. The dynamic adjustment enables Ahura to decide on-the-fly based on the current situation; hence, it eliminates the need for prior knowledge about the characteristics of the track. The driving performance of Ahura is compared with other state-of-the-art controllers on 40 tracks when they drive identical cars. Our experiments indicate that Ahura performs significantly better than other controllers in terms of damage and completion time especially on complex tracks (road tracks). Also, experiments show that the overtaking strategy of Ahura is safer and more effective compared to other controllers.
Autors: Mohammad Reza Bonyadi;Zbigniew Michalewicz;Samadhi Nallaperuma;Frank Neumann;
Appeared in: IEEE Transactions on Computational Intelligence and AI in Games
Publication date: Sep 2017, volume: 9, issue:3, pages: 290 - 304
Publisher: IEEE
 
» Air-SSLAM: A Visual Stereo Indoor SLAM for Aerial Quadrotors
Abstract:
In this letter, we introduce a novel method for visual simultaneous localization and mapping (SLAM)—so-called Air-SSLAM—which exploits a stereo camera configuration. In contrast to monocular SLAM, scale definition and 3-D information are issues that can be more easily dealt with in stereo cameras. Air-SSLAM starts from computing keypoints and the correspondent descriptors over the pair of images, using good features-to-track and rotated-binary robust-independent elementary features, respectively. Then a map is created by matching each pair of right and left frames. The long-term map maintenance is continuously performed by analyzing the quality of each matching, as well as by inserting new keypoints into uncharted areas of the environment. Three main contributions can be highlighted in our method: 1) a novel method to match keypoints efficiently; 2) three quality indicators with the aim of speeding up the mapping process; and 3) map maintenance with uniform distribution performed by image zones. By using a drone equipped with a stereo camera, flying indoor, the translational average error with respect to a marked ground truth was computed, demonstrating promising results.
Autors: Pompilio Araújo;Rodolfo Miranda;Diedre Carmo;Raul Alves;Luciano Oliveira;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Sep 2017, volume: 14, issue:9, pages: 1643 - 1647
Publisher: IEEE
 
» Airborne Transient Electromagnetic Modeling and Inversion Under Full Attitude Change
Abstract:
During airborne transient electromagnetic (EM) surveys, transmitting and receiving antennas change their attitudes as the inevitable result of pilot maneuvers and natural forces, which makes the EM response different from that of the nominal attitudes when the antennas are straight and level. Attitude changes were usually neglected or partially considered in the past, which are not adequate for a quantitative interpretation. In this letter, we first scrutinize the mechanism of how the attitude change affects the EM response and divides these effects into two parts: the pure attitude effect and the resultant translation effect. Then, we introduce a novel method to involve the full attitude change in both modeling and inversion. Our compelling results finally demonstrate that the attitude change affects the early-time response much more than the late time and involving the full change in inversion can produce a better estimate of shallow geoelectric parameters.
Autors: Youzheng Qi;Ling Huang;Xucun Wang;Guangyou Fang;Gang Yu;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Sep 2017, volume: 14, issue:9, pages: 1575 - 1579
Publisher: IEEE
 
» Aircraft Strain WSN Powered by Heat Storage Harvesting
Abstract:
The combination of ultra-low-power wireless communications and energy harvesting enables the realization of autonomous wireless sensor networks. Such networks can be usefully applied in commercial aircraft where wireless sensing solutions contribute to weight reduction and increased ease of installation and maintenance. This paper presents, for the first time, a complete energy-autonomous wireless strain monitoring system for aircraft. The system is based on a multimode wireless time-division multiple access (TDMA) medium access control (MAC) protocol that supports automatic configuration and a time-stamping accuracy better than 1 ms. The energy supply depends solely on an innovative thermoelectric energy harvester, which takes advantage of the changes in environmental temperature during takeoff and landing. The system was successfully integrated and passed the functional and flight-clearance tests that qualify it for use in a flight-test installation.
Autors: L. V. Allmen;G. Bailleul;Th. Becker;J.-D. Decotignie;M. E. Kiziroglou;C. Leroux;P. D. Mitcheson;J. Müller;D. Piguet;T. T. Toh;A. Weisser;S. W. Wright;E. M. Yeatman;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 7284 - 7292
Publisher: IEEE
 
» Airport Detection Based on a Multiscale Fusion Feature for Optical Remote Sensing Images
Abstract:
Automatically detecting airports from remote sensing images has attracted significant attention due to its importance in both military and civilian fields. However, the diversity of illumination intensities and contextual information makes this task difficult. Moreover, auxiliary features both within and surrounding the regions of interest are usually ignored. To address these problems, we propose a novel method that uses a multiscale fusion feature to represent the complementary information of each region proposal, which is extracted by constructing a GoogleNet with a light feature module model that has an additional light fully connected layer. Then, the fusion feature is input to a support vector machine whose performance is enhanced using a hard negative mining method. Finally, a simplified localization method is applied to tackle the problem of box redundancy and to optimize the locations of airports. An experiment demonstrates that the fusion feature outperforms other features on airport detection tasks from remote sensing images containing complicated contextual information.
Autors: Zhifeng Xiao;Yiping Gong;Yang Long;Deren Li;Xiaoying Wang;Hua Liu;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Sep 2017, volume: 14, issue:9, pages: 1469 - 1473
Publisher: IEEE
 
» Algorithm and Architecture Design of Adaptive Filters With Error Nonlinearities
Abstract:
This paper presents a framework based on the logarithmic number system to implement adaptive filters with error nonlinearities in hardware. The framework is demonstrated through pipelined implementations of two recently proposed adaptive filtering algorithms based on logarithmic cost, namely, least mean logarithmic square (LMLS) and least logarithmic absolute difference (LLAD). To the best of our knowledge, the proposed architectures are the first attempts to implement both LMLS and LLAD algorithms in hardware. We derive error computing algorithms to realize the nonlinear error functions for LMLS and LLAD and map them onto hardware. We also propose a novel variable- scheme to enhance the original LMLS algorithm and prove its robustness and suitability for VLSI implementations in practical applications. Detailed bit width and error analysis are carried out for the proposed VLSI fixed point implementations. Postlayout implementation results show that with an additional multiplier over conventional least mean square (LMS), 7-dB improvement in steady-state mean square deviation performance can be achieved and with the proposed variable- scheme, 12-dB improvement can be achieved without compromising the convergence. We will show that LMLS can potentially replace LMS in practical applications, by demonstrating a proof-of-concept by extending the framework to transform domain adaptive filters.
Autors: Subrahmanyam Mula;Vinay Chakravarthi Gogineni;Anindya Sundar Dhar;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Sep 2017, volume: 25, issue:9, pages: 2588 - 2601
Publisher: IEEE
 
» All Analog Processing of Speckle Affected Self-Mixing Interferometric Signals
Abstract:
Self-mixing (SM) or optical feedback interferometry has been extensively used for high precision displacement and vibration sensing. However, presence of speckle can significantly degrade the SM interferometric signal and cause changes in signal amplitude as well as in the operating optical feedback regime, resulting in reduction in measurement precision. Previously, different advanced digital signal processing techniques have been proposed to undo the effects caused by speckle. However, their complex and computationally heavy nature inhibits their use for real-time, high bandwidth sensing applications. In this regard, an all analog signal processing algorithm has been presented in this paper, which allows real-time processing of speckle affected SM signal while using standard analog circuits. Various simulations indicated that it is able to correctly process speckle affected SM signals having amplitude variation of at least one order and optical feedback parameter reduction until 0.5. This proposed algorithm has been tested on experimentally acquired speckle affected SM signals and found capable of dealing with variations in optical feedback regime and amplitude modulation of SM signals, in accordance with simulation results. The developed hardware prototype circuit measures a maximum displacement amplitude of 0.4 mm at a maximum target velocity of 8 mm/s for an SM sensor with a laser wavelength of 785 nm as long as . The proposed all analog processing could be a significant step toward a robust, low-cost, integrated, real-time SM displacement sensor.
Autors: Asra A. Siddiqui;Usman Zabit;Olivier D. Bernal;Gulistan Raja;Thierry Bosch;
Appeared in: IEEE Sensors Journal
Publication date: Sep 2017, volume: 17, issue:18, pages: 5892 - 5899
Publisher: IEEE
 
» All-Digital Calibration of Timing Mismatch Error in Time-Interleaved Analog-to-Digital Converters
Abstract:
This paper presents an all-digital background calibration for timing mismatch in time-interleaved analog-to-digital converters (TI-ADCs). It combines digital adaptive timing mismatch estimation and digital derivative-based correction, achieving lower hardware cost and better suppression of timing mismatch tones than previous work. In addition, for the first time closed-form exact expressions for the signal-to-noise and distortion ratio (SNDR) of a four-channel TI-ADC with timing mismatch after derivative-based digital correction are obtained, which can be used to guide the design. Simulation results of a four-channel TI-ADC behavioral model and measurement results from a commercial 12-bit 3.6-GS/s two-channel TI-ADC show that the proposed all-digital calibration can accurately estimate the timing skew and effectively correct the timing mismatch errors, while also confirming the analytic SNDR expressions.
Autors: Shuai Chen;Luke Wang;Hong Zhang;Rosanah Murugesu;Dustin Dunwell;Anthony Chan Carusone;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Sep 2017, volume: 25, issue:9, pages: 2552 - 2560
Publisher: IEEE
 
» AllFocus: Patch-Based Video Out-of-Focus Blur Reconstruction
Abstract:
Amateur videos always contain focusing issues. A focusing mistake may produce out-of-focus blur, which seriously degrades the expressive force of the video. In this paper, we propose a patch-based method to remove the out-of-focus blur of a video and build an all-in-focus video. We assume that the out-of-focus blurry region in one frame will be clear in a portion of other frames; thus, the clear corresponding regions can be used to reconstruct the blurry one. We divide each video frame into a grid of patches and track each patch in the surrounding frames. We independently reconstruct each video frame by building a Markov random field model to identify the optimal target patches that are sharp, similar to the original patches, and are coherent with their neighboring patches within the overlapped regions. To recover an all-in-focus video, an iterative framework is utilized, in which the reconstructed video of each iteration is substituted in the next iteration. Finally, we employ the idea of a bilateral filter to temporally smooth the reconstructed video. The experimental results and the comparison with the previous works demonstrate the effectiveness of our method.
Autors: Yinting Wang;Zhenyang Wang;Dapeng Tao;Shaojie Zhuo;Xianghua Xu;Shiliang Pu;Mingli Song;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Sep 2017, volume: 27, issue:9, pages: 1895 - 1908
Publisher: IEEE
 
» Almost Lossless Analog Signal Separation and Probabilistic Uncertainty Relations
Abstract:
We propose an information-theoretic framework for analog signal separation. Specifically, we consider the problem of recovering two analog signals, modeled as general random vectors, from the noiseless sum of linear measurements of the signals. Our framework is inspired by the groundbreaking work of Wu and Verdú (2010) on analog compression and encompasses, inter alia, inpainting, declipping, super-resolution, the recovery of signals corrupted by impulse noise, and the separation of (e.g., audio or video) signals into two distinct components. The main results we report are general achievability bounds for the compression rate, i.e., the number of measurements relative to the dimension of the ambient space the signals live in, under either measurability or Hölder continuity imposed on the separator. Furthermore, we find a matching converse for sources of mixed discrete-continuous distribution. For measurable separators our proofs are based on a new probabilistic uncertainty relation, which shows that the intersection of generic subspaces with general sets of sufficiently small Minkowski dimension is empty. Hölder continuous separators are dealt with by introducing the concept of regularized probabilistic uncertainty relations. The probabilistic uncertainty relations we develop are inspired by embedding results in dynamical systems theory due to Sauer et al. (1991) and—conceptually—parallel classical Donoho-Stark and Elad-Bruckstein uncertainty principles at the heart of compressed sensing theory. Operationally, the new uncertainty relations take the theory of sparse signal separation beyond traditional sparsity—as measured in terms of the number of non-zero entries—to the more general notion of low description complexity as quantified by Minkowski dimension. Finally, our approach also allows to significantly strengthen- key results in Wu and Verdú (2010).
Autors: David Stotz;Erwin Riegler;Eirikur Agustsson;Helmut Bölcskei;
Appeared in: IEEE Transactions on Information Theory
Publication date: Sep 2017, volume: 63, issue:9, pages: 5445 - 5460
Publisher: IEEE
 
» Almost Tight Spectral Graph Wavelets With Polynomial Filters
Abstract:
The construction of spectral filters for graph wavelet transforms is addressed in this paper. Both the undecimated and decimated cases will be considered. The filter functions are polynomials and can be implemented efficiently without the need for any eigendecomposition, which is computationally expensive for large graphs. Polynomial filters also have the advantage of the vertex localization property. The construction is achieved by designing suitable transformations that are used on traditional multirate filter banks. It will be shown how the classical quadrature-mirror-filters and linear phase, critically/over- sampled filter banks can be used to construct spectral graph wavelets that are almost tight. A variety of design examples will be given to show the versatility of the design technique.
Autors: David B. H. Tay;Yuichi Tanaka;Akie Sakiyama;
Appeared in: IEEE Journal of Selected Topics in Signal Processing
Publication date: Sep 2017, volume: 11, issue:6, pages: 812 - 824
Publisher: IEEE
 
» Alternative Surface Integral Equation Formulations for Characteristic Modes of Dielectric and Magnetic Bodies
Abstract:
In this paper, the physical meanings and various computing methods of characteristic modes (CMs) of dielectric and magnetic bodies are investigated. Two types of surface integral equation (SIE) formulations based on the dependent relationships between the equivalent surface electric and magnetic currents are proposed. Following the two types of SIE formulations, two generalized eigenvalue equations are established to determine the CMs of dielectric or magnetic bodies. This is in contrast to the approach using induced volume currents. It is found that the eigenvalues possess clear physical meanings similar to those of perfectly electric conducting bodies. The CMs can be used to describe the resonant features, including resonant frequencies and resonant field distributions. Numerical results are presented to validate the proposed formulations.
Autors: Renzun Lian;Jin Pan;Shaode Huang;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2017, volume: 65, issue:9, pages: 4706 - 4716
Publisher: IEEE
 
» Ambient Backscatter: A New Approach to Improve Network Performance for RF-Powered Cognitive Radio Networks
Abstract:
This paper introduces a new solution to improve the performance for secondary systems in radio frequency (RF) powered cognitive radio networks (CRNs). In a conventional RF-powered CRN, the secondary system works based on the harvest-then-transmit protocol. That is, the secondary transmitter (ST) harvests energy from primary signals and then uses the harvested energy to transmit data to its secondary receiver (SR). However, with this protocol, the performance of the secondary system is much dependent on the amount of harvested energy as well as the primary channel activity, e.g., idle and busy periods. Recently, ambient backscatter communication has been introduced, which enables the ST to transmit data to the SR by backscattering ambient signals. Therefore, it is potential to be adopted in the RF-powered CRN. We investigate the performance of RF-powered CRNs with ambient backscatter communication over two scenarios, i.e., overlay and underlay CRNs. For each scenario, we formulate and solve the optimization problem to maximize the overall transmission rate of the secondary system. Numerical results show that by incorporating such two techniques, the performance of the secondary system can be improved significantly compared with the case when the ST performs either harvest-then-transmit or ambient backscatter technique.
Autors: Dinh Thai Hoang;Dusit Niyato;Ping Wang;Dong In Kim;Zhu Han;
Appeared in: IEEE Transactions on Communications
Publication date: Sep 2017, volume: 65, issue:9, pages: 3659 - 3674
Publisher: IEEE
 
» An AC Power Standard for Loss Measurement Systems for Testing Power Transformers
Abstract:
An ac power standard for high voltages and high currents for power frequencies is presented. It consists of commercially available components and is traceable to the primary standards of Physikalisch-Technische Bundesanstalt. A dedicated correction algorithm automatically corrects the systematic errors of the components and leads to an uncertainty on the order of 40 /VA of the active power for voltages up to 220 kV/ and up to 2 kA at any power factor. It is intended to use this standard for calibrating reference measuring systems of accredited laboratories offering calibration service for calibrating industrial power transformer test systems or for manufacturers of such industrial measurement systems.
Autors: Enrico Mohns;Peter Räther;Henrik Badura;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Sep 2017, volume: 66, issue:9, pages: 2225 - 2232
Publisher: IEEE
 
» An Accurate Semianalytical Waveform Model for Mispointed SAR Interferometric Altimeters
Abstract:
Synthetic aperture radar (SAR) altimeters reduce the along-track footprint size exploiting the coherence of the transmitted pulses and achieve at the same time a noise reduction. Consequently, a large effort has been aimed at the formulation of theoretical models that apply to SAR altimeters, in order to fully exploit the improvement in spatial resolution obtained from the along-track aperture synthesis. This letter presents a novel semianalytical waveform model for SAR interferometric altimeters that preserves high accuracy even in the presence of mispointing. Starting from the waveform model proposed by Wingham et al. that provides a unified formulation for pulse-limited and SAR interferometric altimeters which can only be computed numerically, here, we describe a semianalytical approximation for small variations of the mispointing angles around an arbitrary combination of pitch and roll angles . The proposed semianalytical waveform model allows to reduce the high dimensionality of the model proposed by Wingham et al. and it has been proven to be accurate for variations of mispointing angles up to 0.4 deg around the . The performance of the proposed formulation has been evaluated on simulated data from Sentinel-6 configuration and on real data from CryoSat-2 SARin acquisitions over ocean.
Autors: Lisa Recchia;Michele Scagliola;Davide Giudici;Mieke Kuschnerus;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Sep 2017, volume: 14, issue:9, pages: 1537 - 1541
Publisher: IEEE
 
» An Adaptive Parallel Algorithm for Computing Connected Components
Abstract:
We present an efficient distributed memory parallel algorithm for computing connected components in undirected graphs based on Shiloach-Vishkin’s PRAM approach. We discuss multiple optimization techniques that reduce communication volume as well as load-balance the algorithm. We also note that the efficiency of the parallel graph connectivity algorithm depends on the underlying graph topology. Particularly for short diameter graph components, we observe that parallel Breadth First Search (BFS) method offers better performance. However, running parallel BFS is not efficient for computing large diameter components or large number of small components. To address this challenge, we employ a heuristic that allows the algorithm to quickly predict the type of the network by computing the degree distribution and follow the optimal hybrid route. Using large graphs with diverse topologies from domains including metagenomics, web crawl, social graph and road networks, we show that our hybrid implementation is efficient and scalable for each of the graph types. Our approach achieves a runtime of 215 seconds using 32 K cores of Cray XC30 for a metagenomic graph with over 50 billion edges. When compared against the previous state-of-the-art method, we see performance improvements up to 24 .
Autors: Chirag Jain;Patrick Flick;Tony Pan;Oded Green;Srinivas Aluru;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Sep 2017, volume: 28, issue:9, pages: 2428 - 2439
Publisher: IEEE
 
» An Advanced Multiscale Edge Detector Based on Gabor Filters for SAR Imagery
Abstract:
The ratio of averages is a robust edge detector which provides the property of constant false alarm rate for synthetic aperture radar (SAR) imagery. However, the rectangular window used in the calculation of local mean may cause numerous false maxima. The size of the processing window also has a significant effect on the detection performance, but it is difficult to determine the optimum window size. In this letter, we first propose a new ratio-based detector that is constructed by the Gabor odd filter. The scale of the proposed detector is related to the size of the processing window. Then, edge strength maps extracted by multiscale detectors are combined using an edge tracking algorithm to form a final response. We used the receiver operating characteristic curves to evaluate the performance of the proposed detector. The experimental results on simulated and real-world SAR images show that the proposed multiscale edge detector yields an accurate and consecutive edge response.
Autors: Yuming Xiang;Feng Wang;Ling Wan;Hongjian You;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Sep 2017, volume: 14, issue:9, pages: 1522 - 1526
Publisher: IEEE
 
» An Approximate Dynamic Programming Approach to Multiagent Persistent Monitoring in Stochastic Environments With Temporal Logic Constraints
Abstract:
We consider the problem of generating control policies for a team of robots moving in a stochastic environment. The team is required to achieve an optimal surveillance mission, in which a certain “optimizing proposition” needs to be satisfied infinitely often. In addition, a correctness requirement expressed as a temporal logic formula is imposed. By modeling the robots as game transition systems and the environmental elements as Markov chains, the problem reduces to finding an optimal control policy for a Markov decision process, which also satisfies a temporal logic specification. The existing approaches based on dynamic programming are computationally intensive, thus not feasible for large environments and/or large numbers of robots. We propose an approximate dynamic programming (ADP) framework to obtain suboptimal policies with reduced computational complexity. Specifically, we choose a set of basis functions to approximate the optimal costs and find the best approximation through the least-squares method. We also propose a simulation-based ADP approach to further reduce the computational complexity by employing low-dimensional calculations and simulation samples.
Autors: Kun Deng;Yushan Chen;Calin Belta;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Sep 2017, volume: 62, issue:9, pages: 4549 - 4563
Publisher: IEEE
 
» An Approximate Transfer Function Model of Two Serially Connected Heterogeneous Transmission Lines
Abstract:
This brief presents an approximate transfer function model of two heterogeneous transmission lines connected in series. The proposed model is simple, intuitive, and can accurately describe the frequency response of various serially connected heterogeneous interconnects which satisfy a validity condition. The exact error of the proposed model is also provided. According to our analysis, the validity condition can be clearly interpreted by the propagation and the reflection waves. The accuracy of the proposed model is verified by comparing the calculated transfer function of LC-dominant off-chip and RC-dominant on-chip examples against SPICE simulation results. In these verifications, the maximum errors between calculation and simulation are, respectively, 2.58% and 3.32% for off-chip and on-chip examples. The computation time is also reduced about 29.76 and 289.07 times compared with a single-channel model and the SPICE -element model. With the proposed model, designers can easily understand the channel responses of diverse serially connected heterogeneous interconnects.
Autors: Jaeyoung Seo;Minsoo Choi;Sanquan Song;Jae-Yoon Sim;Hong-June Park;Byungsub Kim;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Sep 2017, volume: 64, issue:9, pages: 1067 - 1071
Publisher: IEEE
 
» An Architecture for Capturing the Nonlinear Distortion of Analog Self-Interference Cancellers in Full-Duplex Radios
Abstract:
Analog self-interference (SI) cancellation is a key process to enable full-duplex wireless communications, which generates a cancelling signal (a copy of the SI) at the local receiver and subtracts from the received signal to cancel the SI imposed by the local transmitter. However, due to the inherent nonlinearities of analog canceller (AC), the SI cancellation performance is often restricted by introducing extra nonlinear distortion to the receiver. In this letter, an observation architecture is proposed to capture the AC nonlinear distortion by deploying an auxiliary chain identical to the AC and a linear cancellation approach. The captured nonlinear distortion could be used as a reference in the digital domain to mitigate the AC-induced nonlinear interference at the receiver. Experiments verify that the proposed architecture is capable of capturing the weak AC-induced distortion and suppressing it to close the receiver noise floor.
Autors: Ying Liu;Wanzhi Ma;Xin Quan;Wensheng Pan;Kai Kang;Youxi Tang;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Sep 2017, volume: 27, issue:9, pages: 845 - 847
Publisher: IEEE
 
» An Automatic Algorithm to Retrieve Wave Height From X-Band Marine Radar Image Sequence
Abstract:
A new method is proposed to retrieve wave height from an X-band marine radar image sequence, without external measurements for reference. The X-band marine radar image sequence is first decomposed by empirical orthogonal function (EOF), and then the sea surface height profile is reconstructed and scaled from the first EOF mode. The radial profiles that are close to the peak wave direction are used to extract the zero-crossing wave periods and relative wave heights. The spectral width parameter is deduced from the histogram of a dimensionless wave period. Based on a joint probability distribution function (pdf) of a dimensionless wave period and wave height, the theoretical pdf of the wave height is derived. A shape parameter is defined for the theoretical pdf and the histogram of the relative wave heights, and then the calibration coefficient is estimated. The method is validated by comparing the significant wave heights retrieved from two different X-band marine radar systems with those measured by buoy; the correlation coefficient, the root-mean-square error, and the bias between them are 0.78, 0.51 m, and −0.19 m for HH polarization, while they are 0.77, 0.51 m, and 0.19 m for VV polarization, respectively. The sources of error of the method are discussed.
Autors: Zhongbiao Chen;Yijun He;Biao Zhang;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Sep 2017, volume: 55, issue:9, pages: 5084 - 5092
Publisher: IEEE
 
» An Auxiliary Particle Filtering Algorithm With Inequality Constraints
Abstract:
For nonlinear non-Gaussian stochastic dynamic systems with inequality state constraints, this technical note presents an efficient particle filtering algorithm, constrained auxiliary particle filtering algorithm. To deal with the state constraints, the proposed algorithm probabilistically selects particles such that those particles far away from the feasible area are less likely to propagate into the next time step. To improve on the sampling efficiency in the presence of inequality constraints, it uses a highly effective method to perform a series of constrained optimization so that the importance distributions are constructed efficiently based on the state constraints. The caused approximation errors are corrected using the importance sampling method. This ensures that the obtained particles constitute a representative sample of the true posterior distribution. A simulation study on vehicle tracking is used to illustrate the proposed approach.
Autors: Baibing Li;Cunjia Liu;Wen-Hua Chen;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Sep 2017, volume: 62, issue:9, pages: 4639 - 4646
Publisher: IEEE
 
» An Easy and Efficient Method for Synthesizing Two-Dimensional Finite Impulse Response Filters with Improved Selectivity [Tips & Tricks]
Abstract:
It is hard to imagine what the world would look like without the modern technologies using digital signal processing. The developments in this technical field provide an opportunity for building technical devices that implement mathematical methods unattainable by analog technology. Many modern technical devices work with two-dimensional (2-D) signals in a process called digital image processing, and 2-D digital finite impulse response (FIR) filters are basic technical tools in image processing. FIR filters are extensively used in digital television, radio astronomy, radio location, biomedicine, and so on.
Autors: Peter S. Apostolov;Borislav P. Yurukov;Alexey K. Stefanov;
Appeared in: IEEE Signal Processing Magazine
Publication date: Sep 2017, volume: 34, issue:5, pages: 180 - 183
Publisher: IEEE
 
» An Economical and SLO-Guaranteed Cloud Storage Service Across Multiple Cloud Service Providers
Abstract:
It is important for cloud service brokers to provide a multi-cloud storage service to minimize their payment cost to cloud service providers (CSPs) while providing service level objective (SLO) guarantee to their customers. Many multi-cloud storage services have been proposed or payment cost minimization or SLO guarantee. However, no previous works fully leverage the current cloud pricing policies (such as resource reservation pricing) to reduce the payment cost. Also, few works achieve both cost minimization and SLO guarantee. In this paper, we propose a multi-cloud Economical and SLO-guaranteed Storage Service (), which determines data allocation and resource reservation schedules with payment cost minimization and SLO guarantee. incorporates (1) a coordinated data allocation and resource reservation method, which allocates each data item to a datacenter and determines the resource reservation amount on datacenters by leveraging all the pricing policies; (2) a genetic algorithm based data allocation adjustment method, which reduce data Get/Put rate variance in each datacenter to maximize the reservation benefit. We also propose several algorithms to enhance the cost efficient and SLO guarantee performance of including i) dynamic request redirection, ii) grouped Gets for cost reduction, iii) lazy update for cost-efficient Puts, and iv) concurrent requests for rigid Get SLO guarantee. Our trace-driven experiments on a supercomputing cluster and on real clouds (i.e., Amazon S3, Windo- s Azure Storage and Google Cloud Storage) show the superior performance of in payment cost minimization and SLO guarantee in comparison with previous methods.
Autors: Guoxin Liu;Haiying Shen;Haoyu Wang;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Sep 2017, volume: 28, issue:9, pages: 2440 - 2453
Publisher: IEEE
 
» An Effective Fuzzy Feature Selection and Prediction Method for Modeling Tidal Current: A Case of Persian Gulf
Abstract:
This paper develops a new two-stage approach for accurate modeling and prediction of tidal current. The proposed method makes use of a novel fuzzy feature selection to extract the most preferable features from the tidal current speed and direction data set. The selected features are further used to train a support vector regression for accurate prediction. The setting parameters of the proposed model are trained by a new optimization algorithm based on the harmony search algorithm to get to the most optimal training targets. The proposed optimization algorithm makes use of the crossover and mutation operators from genetic algorithm to escape from the local optima and find the global solutions. Experimental tidal data from Persian Gulf, Iran, are used to assess the accuracy and performance of the proposed model. The results show the appropriate performance and high precision of the proposed model in comparison with other famous methods.
Autors: Behnaz Papari;Chris S. Edrington;Farzaneh Kavousi-Fard;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Sep 2017, volume: 55, issue:9, pages: 4956 - 4961
Publisher: IEEE
 
» An Efficient Autocalibration Method for Triaxial Accelerometer
Abstract:
This paper investigates the autocalibration of microelectromechanical systems (MEMS) triaxial accelerometer (TA) based on experimental design (DoE). First, for a special 6-parameter second-degree model, a six-point experimental scheme is proposed, and its G-optimality has been proven based on optimal DoE. Then, a new linearization approach is introduced, by which the TA model for autocalibration can be simplified as the expected second-degree form so that the proposed optimal experimental scheme can be applied. To reliably estimate the model parameter, a convergence-guaranteed iterative algorithm is also proposed, which can significantly reduce the bias caused by linearization. Thereafter, the effectiveness and robustness of the proposed approach have been demonstrated by simulation. Finally, the proposed calibration method has been experimentally verified using two typical types of MEMS TA, and desired experimental results effectively demonstrate the efficiency and accuracy of the proposed calibration approach.
Autors: Lin Ye;Ying Guo;Steven W. Su;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Sep 2017, volume: 66, issue:9, pages: 2380 - 2390
Publisher: IEEE
 
» An Efficient Fast Algorithm for Accelerating the Time-Domain Integral Equation Discontinuous Galerkin Method
Abstract:
An efficient fast algorithm for accelerating the time-domain integral equation discontinuous Galerkin (TDIEDG) method for analyzing the transient scattering from electrically large complex objects is proposed. The TDIEDG is discretized using the monopolar Rao–Wilton–Glisson (RWG) function and shifted Lagrange polynomial function in spatial and time domain, respectively. The final system of equations can be solved iteratively using the classical marching-on-in-time scheme. Taking advantage of the approximate evaluation of the vector and scalar potential terms combined with the Taylor series expansion of the transient far field, the computational burden of the TDIEDG solver has been significantly reduced. In addition, it is flexible and convenient to analyze object with nonconformal discretization due to the employment of the monopolar RWG functions.
Autors: G. S. Cheng;D. Z. Ding;R. S. Chen;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2017, volume: 65, issue:9, pages: 4919 - 4924
Publisher: IEEE
 
» An Efficient Heterogeneous Memristive xnor for In-Memory Computing
Abstract:
Resistive RAM (RRAM) technologies are gaining importance due to their appealing characteristics, which include non-volatility, small form factor, low power consumption, and ability to perform logic operations in memory. These characteristics make RRAM highly suited for Internet of Things devices and similarly resource-constrained systems. This paper proposes a novel memristor-based xnor gate that enables the execution of xnor/xor function in the memristive crossbar memory. The proposed two-input xnor gate requires two steps to perform the xnor function. The design of the circuit utilizes bipolar and unipolar memristors and permits cascading by only adding an extra step and one computing memristor. To the best of our knowledge, this is the first native stateful xnor logic implementation. Spice simulations have been used to verify the functionality of the proposed circuit. This includes benchmarking the proposed design against the state-of-the-art stateful memristor-based logic circuits. The results for implementing three-input xor using the proposed circuit demonstrate efficient performance in terms of energy, latency, and area. The gate shows 56% saving in energy, 54% less number of steps (latency), and 50% less number of computing MR (area) compared with the state-of-the-art stateful xor/xnor implementations.
Autors: Muath Abu Lebdeh;Heba Abunahla;Baker Mohammad;Mahmoud Al-Qutayri;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Sep 2017, volume: 64, issue:9, pages: 2427 - 2437
Publisher: IEEE
 
» An Efficient Precoder Size for Interference Alignment of the $K$ -User Interference Channel
Abstract:
In this letter, we explore interference alignment for the -user single input single output interference channel with more efficient precoder sizes and lower sensitivity to channel state information at transmitters (CSIT). The main idea in this letter is to divide transmission time into some distinct blocks and select a subset of transmitters and receivers for signaling in each block. We show that our method can achieve more sum degrees-of-freedom compared with other schemes in the limited number of channel extensions. Furthermore, our method needs no full CSIT to be applicable which can be considered as another advantage of this letter.
Autors: Milad Johnny;Mohammad Reza Aref;
Appeared in: IEEE Communications Letters
Publication date: Sep 2017, volume: 21, issue:9, pages: 1941 - 1944
Publisher: IEEE
 
» An Emergency-Demand-Response Based Under Speed Load Shedding Scheme to Improve Short-Term Voltage Stability
Abstract:
The dynamics of load, especially induction motors, are the driving force for short-term voltage stability (STVS) problems. In this paper, the equivalent rotation speed of motors is identified online and its recovery time is estimated next to realize an emergency-demand-response (EDR) based under speed load shedding (USLS) scheme to improve STVS. The proposed scheme consists of an EDR program and two regular stages (RSs). In the EDR program, contracted load is used as a fast-response resource rather than the last defense. The estimated recovery time (ERT) is used as the triggering signal for the EDR program. In the RSs, the amount of load to be shed at each bus is determined according to the assigned weights based on ERTs. Case studies on a practical power system in China Southern Power Grid have validated the performance of the proposed USLS scheme under various contingency scenarios. The utilization of EDR resources and the adaptive distribution of shedding amount in RSs guarantee faster voltage recovery. Therefore, USLS offers a new and more effective approach compared with existing under voltage load shedding to improve STVS.
Autors: Yipeng Dong;Xiaorong Xie;Ke Wang;Baorong Zhou;Qirong Jiang;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2017, volume: 32, issue:5, pages: 3726 - 3735
Publisher: IEEE
 
» An Empirical Study on the Effect of Testing on Code Quality Using Topic Models: A Case Study on Software Development Systems
Abstract:
Previous research in defect prediction has proposed approaches to determine which files require additional testing resources. However, practitioners typically create tests at a higher level of abstraction, which may span across many files. In this paper, we study software testing, especially test resource prioritization, from a different perspective. We use topic models to generate topics that provide a high-level view of a system, allowing developers to look at the test case coverage from a different angle. We propose measures of how well tested and defect prone a topic is, allowing us to discover which topics are well tested and which are defect prone. We conduct case studies on the histories of Mylyn, Eclipse, and NetBeans. We find that 34–78% of topics are shared between source code and test files, indicating that we can use topic models to study testing; well-tested topics are usually less defect prone, defect-prone topics are usually undertested; we can predict which topics are defect prone but not well tested with an average precision and recall of 75% and 77%, respectively; our approach complements traditional prediction-based approaches by saving testing and code inspection effort; and our approach is not particularly sensitive to the parameters that we use.
Autors: Tse-Hsun Chen;Stephen W. Thomas;Hadi Hemmati;Meiyappan Nagappan;Ahmed E. Hassan;
Appeared in: IEEE Transactions on Reliability
Publication date: Sep 2017, volume: 66, issue:3, pages: 806 - 824
Publisher: IEEE
 
» An FSS Structure With Geometrically Separable Meander-Line Inductors and Parallel-Plate Capacitors
Abstract:
A frequency selective surface (FSS) structure with geometrically separable meander-line inductors (MLIs) and parallel-plate capacitors (PPCs) is proposed. For this FSS structure, the filtering responses for different polarizations and resonance frequencies are realized through separate subcells. For example, to achieve a single-band bandpass performance, two subcells, acting as parallel LC resonators for transverse-electric and transverse-magnetic polarizations, respectively, are implemented by MLIs and PPCs. Because the MLIs and PPCs provide increased equivalent inductance and capacitance, respectively, this FSS provides a miniaturized unit cell size of refers to the resonance wavelength), and its −3 dB bandwidth can be designed by independently adjusting the equivalent inductance and capacitance. A design example shows the easy control of −3 dB bandwidth ranging from 13.6% to 49% with respect to the center frequency. Furthermore, because of the separable subcells, the FSS performances for different polarizations are independently controllable, and it can be readily extended to achieve dual-band bandpass performance with a band ratio ranging from 1.35 to 3.8. In addition, to model the FSS frequency performance precisely, equivalent circuits and closed forms are developed, which serve as a substitute for commercial software for efficient FSS design. Finally, some prototypes are fabricated and measured. All the measured results show that the proposed FSS designs exhibit stable performance under different polarizations and incidence angles (up to 60°), and they exhibit good consistency with those from the full-wave simulations.
Autors: Peng-Chao Zhao;Zhi-Yuan Zong;Wen Wu;Bo Li;Da-Gang Fang;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2017, volume: 65, issue:9, pages: 4693 - 4705
Publisher: IEEE
 
» An Image Reconstruction Algorithm for Electrical Impedance Tomography Using Adaptive Group Sparsity Constraint
Abstract:
Image quality has long been deemed a key challenge for electrical impedance tomography (EIT). High-quality image is of great significance for improving the qualitative and quantitative imaging performance in biomedical or industrial applications. In this paper, a novel image reconstruction algorithm for EIT using adaptive group sparsity constraint is proposed to obtain enhanced image quality. The proposed algorithm takes both the underlying structure characteristics and sparsity prior of the conductivity distribution into account to promote a solution with group sparsity structure and reduce the degree of freedom. Specifically, an adaptive grouping method is incorporated for efficient and dynamic pixel grouping when the conductivity distribution does not have a fixed structure or the prior knowledge of the structure is unavailable. Numerical simulation and phantom experiments are performed to validate the proposed algorithm. The results are compared with those using the Landweber iteration, total variation regularization, and regularization. Both simulation and experiment results confirm the significantly improved tomographic imaging quality using the proposed algorithm, which demonstrates great potential for multiphase flow imaging and biological tissue imaging.
Autors: Yunjie Yang;Jiabin Jia;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Sep 2017, volume: 66, issue:9, pages: 2295 - 2305
Publisher: IEEE
 
» An Improved DAQ-Based Method for Ferrite Characterization
Abstract:
In this paper, we propose an improved version of the classical volt-amperometric measurement method for the characterization of magnetic hysteresis and losses in soft magnetic cores. Using an appropriate circuital solution for the automatic cancellation of the measurement offset and a synchronous data-acquisition-based scheme for both generation and acquisition of signals, we are able to implement a high performance and low error fully automatic test system. This reduces the testing time, while allowing the use of new segmentation algorithms for the study of both major and minor hysteresis loops and the extraction of all the desired properties. We tested the system on a ferrite core, reproducing results already known from the literature with a higher degree of accuracy and reliability, and propose a test to assess the limits of applicability of the method. Energetic magnetic behavior during the formation of asymmetric minor loops is shown and discussed throughout this paper.
Autors: Carlo Guarnieri Calò Carducci;Mirko Marracci;Filippo Attivissimo;Romano Giannetti;Bernardo Tellini;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Sep 2017, volume: 66, issue:9, pages: 2413 - 2421
Publisher: IEEE
 
» An Improved DPA Countermeasure Based on Uniform Distribution Random Power Generator for IoT Applications
Abstract:
In order to secure the communication in Internet of Things era, a low overhead power analysis countermeasure called uniform distribution random power generator is proposed for stream ciphers. To alter the power signature of protected circuit, ring oscillators, which act as unit power generators, are grouped in a systematic approach to generate additional power with uniform probability distribution. Experiments from the proposed evaluation framework demonstrate that the secret key of unprotected device can be disclosed within 103 power traces with standard differential power analysis attack, whereas the same attack mounted on the proposed scheme cannot be disclosed even after 106 measurements. Moreover, the area and the power overhead are reduced by at least 29% and 22% compared with the state-of-the-art works, respectively.
Autors: Szu-Chi Chung;Chun-Yuan Yu;Sung-Shine Lee;Hsie-Chia Chang;Chen-Yi Lee;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Sep 2017, volume: 64, issue:9, pages: 2522 - 2531
Publisher: IEEE
 
» An Improved Fuzzy Neural Network for Traffic Speed Prediction Considering Periodic Characteristic
Abstract:
This paper proposes a new method in construction fuzzy neural network to forecast travel speed for multi-step ahead based on 2-min travel speed data collected from three remote traffic microwave sensors located on a southbound segment of a fourth ring road in Beijing City. The first-order Takagi–Sugeno system is used to complete the fuzzy inference. To train the evolving fuzzy neural network (EFNN), two learning processes are proposed. First, a -means method is employed to partition input samples into different clusters and a Gaussian fuzzy membership function is designed for each cluster to measure the membership degree of samples to the cluster centers. As the number of input samples increases, the cluster centers are modified and membership functions are also updated. Second, a weighted recursive least squares estimator is used to optimize the parameters of the linear functions in the Takagi–Sugeno type fuzzy rules. Furthermore, a trigonometric regression function is introduced to capture the periodic component in the raw speed data. Specifically, the predicted performance between the proposed model and six traditional models are compared, which are artificial neural network, support vector machine, autoregressive integrated moving average model, and vector autoregressive model. The results suggest that the prediction performances of EFNN are better than those of traditional models due to their strong learning ability. As the prediction time step increases, the EFNN model can consider the periodic pattern and demonstrate advantages over other models with smaller predicted errors and slow raising rate of errors.
Autors: Jinjun Tang;Fang Liu;Yajie Zou;Weibin Zhang;Yinhai Wang;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Sep 2017, volume: 18, issue:9, pages: 2340 - 2350
Publisher: IEEE
 
» An Improved Method of DC Bus Voltage Pulsation Suppression for Asymmetric Wind Power PMSG Systems With a Compensation Unit in Parallel
Abstract:
This paper proposes an improved method of simultaneously suppressing the second harmonic (2h) dc-bus voltage pulsation and torque ripple by a compensation unit in parallel with the dc bus in the wind power permanent magnet synchronous generator (PMSG) system with asymmetric impedance. Compared to the existing methods, the proposed method uses fewer power devices and requires a much lower compensation current. These results in a lower power rating, lower power switch and copper losses, and a smaller compensation inductor in the compensation unit. In addition, the corresponding compensation current control is much simpler to operate. Overall, it is an effective method of suppressing the 2h dc bus voltage, although a dc voltage source is required in the compensation unit. The compensation effectiveness has been experimentally verified on a prototype asymmetric PMSG with inherent asymmetry and deliberately introduced asymmetries.
Autors: Yashan Hu;Zi Qiang Zhu;Milijana Odavic;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2017, volume: 32, issue:3, pages: 1231 - 1239
Publisher: IEEE
 
» An Indoor Wayfinding System Based on Geometric Features Aided Graph SLAM for the Visually Impaired
Abstract:
This paper presents a 6-degree of freedom (DOF) pose estimation (PE) method and an indoor wayfinding system based on the method for the visually impaired. The PE method involves two-graph simultaneous localization and mapping (SLAM) processes to reduce the accumulative pose error of the device. In the first step, the floor plane is extracted from the 3-D camera’s point cloud and added as a landmark node into the graph for 6-DOF SLAM to reduce roll, pitch, and errors. In the second step, the wall lines are extracted and incorporated into the graph for 3-DOF SLAM to reduce , , and yaw errors. The method reduces the 6-DOF pose error and results in more accurate pose with less computational time than the state-of-the-art planar SLAM methods. Based on the PE method, a wayfinding system is developed for navigating a visually impaired person in an indoor environment. The system uses the estimated pose and floor plan to locate the device user in a building and guides the user by announcing the points of interest and navigational commands through a speech interface. Experimental results validate the effectiveness of the PE method and demonstrate that the system may substantially ease an indoor navigation task.
Autors: He Zhang;Cang Ye;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Sep 2017, volume: 25, issue:9, pages: 1592 - 1604
Publisher: IEEE
 
» An Inductive Power Transfer System Supplied by a Multiphase Parallel Inverter
Abstract:
The output power of a single-phase inverter is insufficient for high-power applications, such as fast wireless chargers for electrical vehicles. A higher power level can be obtained via a multiphase parallel resonant inverter, which comes with a possible cost of the unbalance current problem. Coupled inductors with a cyclic cascade connection instead of a complex controller are employed to alleviate this problem. A blocking capacitor is introduced to stop the dc component of the circulating current. Equations for suppressing ability of circulating currents under the proposed topology with various numbers of parallel phases are derived. Main power loss components are analyzed and the reason why multiphase systems with a high output current have a higher efficiency is theoretically explained. A prototype of an inverter with six-phase half-bridge parallel topology is developed and built to verify the theoretical analysis. The prototype is used to supply an inductive power transfer system, which delivers power at a distance of 20 cm. When the receiving power of the 6.87 Ω load in the rectifier is 20 kW, one obtains a 95.6% efficiency measured as the power of the dc-load divided by that of dc-input at the inverter.
Autors: Qijun Deng;Jiangtao Liu;Dariusz Czarkowski;Wenshan Hu;Hong Zhou;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2017, volume: 64, issue:9, pages: 7039 - 7048
Publisher: IEEE
 
» An Inequality on Source-to-Sink Average BER and Its Application on Wireless Sensor Networks
Abstract:
This letter drives a novel inequality expression on source-to-sink average BER (S2S-ABER) for multi-hop communication in a network. The obtained expression is less complex and can be implemented on computationally constraint devices, such as sensor nodes. Moreover, it has been applied to wireless sensor networks to determine the SNR limitations such that S2S-ABER does not exceed a threshold value. This information is helpful in deciding the optimum route between source and sink for reliable data dissemination. Although each route can undergo multiple combinations of channel distributions, a typical case with two different scenarios has been considered in this letter for simplicity.
Autors: Ashish Goswami;Ashok Kumar;
Appeared in: IEEE Communications Letters
Publication date: Sep 2017, volume: 21, issue:9, pages: 2077 - 2080
Publisher: IEEE
 
» An Information-Theoretic Study for Joint Sparsity Pattern Recovery With Different Sensing Matrices
Abstract:
In this paper, we study a support set reconstruction problem for multiple measurement vectors (MMV) with different sensing matrices, where the signals of interest are assumed to be jointly sparse and each signal is sampled by its own sensing matrix in the presence of noise. Using mathematical tools, we develop upper and lower bounds of the failure probability of the support set reconstruction in terms of the sparsity, the ambient dimension, the minimum signal-to-noise ratio, the number of measurement vectors, and the number of measurements. These bounds can be used to provide guidelines for determining the system parameters for various compressed sensing applications with noisy MMV with different sensing matrices. Based on the bounds, we develop necessary and sufficient conditions for reliable support set reconstruction. We interpret these conditions to provide theoretical explanations regarding the benefits of taking more measurement vectors. We then compare our sufficient condition with the existing results for noisy MMV with the same sensing matrix. As a result, we show that noisy MMV with different sensing matrices may require fewer measurements for reliable support set reconstruction, under a sublinear sparsity regime in a low noise-level scenario.
Autors: Sangjun Park;Nam Yul Yu;Heung-No Lee;
Appeared in: IEEE Transactions on Information Theory
Publication date: Sep 2017, volume: 63, issue:9, pages: 5559 - 5571
Publisher: IEEE
 
» An Integrated Dual-Mode CMOS Power Amplifier With Linearizing Body Network
Abstract:
A dual-mode radio frequency CMOS power amplifier (PA) for Internet of Things application is presented, which is integrated with the other circuits in a 55-nm bulk CMOS process. The low-power mode is achieved by reducing the number of turn-on power transistors, which are also used for linearization. The PA has a gain control scheme that functions by controlling the transconductance () of the driver stage. A simple body network is introduced to common gate power transistors to improve the linearity of the PA. It is measured with 802.11n 64-quadrature-amplitude-modulation (MCS7) signal and shows a maximum average power of 16 dBm with a supply current of 222 mA under an error-vector-magnitude of −27 dB, which is packaged in a QFN 5 mm.
Autors: Gwanghyeon Jeong;Seunghoon Kang;Taehwan Joo;Songcheol Hong;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Sep 2017, volume: 64, issue:9, pages: 1037 - 1041
Publisher: IEEE
 
» An Interval Approach to Nonlinear Controller Design for Load-Following Operation of a Small Modular Pressurized Water Reactor
Abstract:
A pressurized water reactor (PWR) is most suitable for load-following operation because of its self-regulating nature. However, rapid power maneuvering at an enhanced rate is heavily constrained by the overall power coefficient of reactivity which depends on both the reactor neutronics and thermal hydraulics. In this paper, a 100 MWe PWR module with an integrated steam generator, is modeled using the nonlinear equations representing both the neutronics and thermal hydraulics. Such a PWR is typically an integrated structure with a steam generator included in the same casing and can either be connected to the grid or connected with other such modules using a multimodular approach to constitute a Nuclear Steam Supply System (NSSS) driving a common turbine and an alternator. In this paper, Nonlinear Dynamic Inversion (NDI) technique is used to design a controller capable of controlling such a reactor for load-following with frequent changes in demand, in both the modes of operation, namely, reactor-follow-turbine and turbine-follow-reactor. With the assumption that the parameters of the reactor vary within intervals as the power varies, an interval approach coupled with NDI ensures that the controller satisfies the operating constraints. The methodology is established for both the modes with credible real-time Hardware-in-Loop (HiL) simulations.
Autors: Debayan Bose;Shohan Banerjee;M. Kumar;P. P. Marathe;Siddhartha Mukhopadhyay;Amitava Gupta;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Sep 2017, volume: 64, issue:9, pages: 2474 - 2488
Publisher: IEEE
 
» An Investigation of High-Temperature (to 300 °C) Safe-Operating-Area in a High-Voltage Complementary SiGe on SOI Technology
Abstract:
Safe-operating-area (SOA) in a high-voltage complementary silicon–germanium (SiGe) (= n-p-n + p-n-p) on silicon-on-insulator (SOI) technology is investigated from 24 °C to 300 °C. Three key reliability degradation regions are identified, including: 1) high-current; 2) mixed-mode; and 3) high-power. The degradation mechanisms, which are operative, including Auger damage, mixed-mode damage, and electrothermal runaway as well as their temperature dependences are identified. Mixed-mode damage exhibits a strong negative temperature coefficient for both n-p-n and p-n-p SiGe heterojunction bipolar transistors (HBTs) up to 300 °C, which leads to an increase in the SOA from a high-voltage perspective. Electrothermal boundaries are also explored by finding and across the – plane up to 300 °C. Both n-p-n and p-n-p SiGe HBTs show an increase in the SOA for the electrothermal boundary as temperature increases. High-current-induced damage, on the other hand, exhibits a positive temperature coefficient, which implies that high current drive should carefully be considered when using SiGe HBT circuits operated in a high-temperature environment. However, at very high temperatures (>200°C), the high current damage processes show annealing properties, which implies that at sufficiently high temperatures, annealing can dominate over Auger damage and potentially extend the SOA of the technolo- y.
Autors: Anup P. Omprakash;Ha Dao;Uppili S. Raghunathan;Hanbin Ying;Partha S. Chakraborty;Jeffrey A. Babcock;Rajarshi Mukhopadhyay;John D. Cressler;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3748 - 3755
Publisher: IEEE
 
» An IoT Endpoint System-on-Chip for Secure and Energy-Efficient Near-Sensor Analytics
Abstract:
Near-sensor data analytics is a promising direction for internet-of-things endpoints, as it minimizes energy spent on communication and reduces network load - but it also poses security concerns, as valuable data are stored or sent over the network at various stages of the analytics pipeline. Using encryption to protect sensitive data at the boundary of the on-chip analytics engine is a way to address data security issues. To cope with the combined workload of analytics and encryption in a tight power envelope, we propose Fulmine, a system-on-chip (SoC) based on a tightly-coupled multi-core cluster augmented with specialized blocks for compute-intensive data processing and encryption functions, supporting software programmability for regular computing tasks. The Fulmine SoC, fabricated in 65-nm technology, consumes less than 20mW on average at 0.8V achieving an efficiency of up to 70pJ/B in encryption, 50pJ/px in convolution, or up to 25MIPS/mW in software. As a strong argument for real-life flexible application of our platform, we show experimental results for three secure analytics use cases: secure autonomous aerial surveillance with a state-of-the-art deep convolutional neural network (CNN) consuming 3.16pJ per equivalent reduced instruction set computer operation, local CNN-based face detection with secured remote recognition in 5.74pJ/op, and seizure detection with encrypted data collection from electroencephalogram within 12.7pJ/op.
Autors: Francesco Conti;Robert Schilling;Pasquale Davide Schiavone;Antonio Pullini;Davide Rossi;Frank Kağan Gürkaynak;Michael Muehlberghuber;Michael Gautschi;Igor Loi;Germain Haugou;Stefan Mangard;Luca Benini;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Sep 2017, volume: 64, issue:9, pages: 2481 - 2494
Publisher: IEEE
 
» An Iterative Design Procedure for Multiband Single-Layer Reflectarrays: Design and Experimental Validation
Abstract:
A novel iterative procedure for designing multiband single-layer reflectarrays is presented. The multiband frequency behavior is achieved by simultaneously providing the desired phases at each operating frequency. A suitable reflectarray element shape formed by several concentric loops loaded with double stubs has been selected for achieving multiband operation. The problem of mutual coupling among the different self-similar resonating elements laying on the same substrate is analyzed and mitigated by employing an innovative iterative design approach. The proposed design approach is demonstrated by designing a tri-band single-layer reflectarray with widely spaced frequencies operating at 3.9 GHz (C-band), 7.5 GHz (X-band), and 12.5 GHz (Ku-band). The single-layer prototype is compact and lightweight as it has been fabricated on a thin Kapton film glued on to a Rohacell HF31 substrate. The overall thickness is approximately /5 at the highest operative frequency. Measurements of the reflectarray radiation patterns agree with the estimated performance and prove the reliability of the proposed synthesis technique.
Autors: Michele Borgese;Filippo Costa;Simone Genovesi;Agostino Monorchio;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2017, volume: 65, issue:9, pages: 4595 - 4606
Publisher: IEEE
 
» An Optimization Scheme of Enhanced Adaptive Dynamic Energy Consumption Based on Joint Network-Channel Coding in WSNs
Abstract:
Energy efficiency in wireless sensor networks is a crucial factor that affects the performance of the networks, as long-time and unceasing energy supply is impossible. Recent studies demonstrated that the previously proposed scheme of joint adaptive network-channel coding (JANCC) and adaptive dynamic energy consumption (ADEC) obtained an excellent performance in terms of energy efficiency. Based on the joint network-channel coding, we propose an enhanced ADEC optimization scheme, which integrates the essence of both JANCC and ADEC, and overcomes the shortcomings of them. In the scheme, an identifier vector is inserted into the feedback information. The relay node is able to acquire the specific signs of the channel codes received in error based on the identifier vector and transmit the network coded packets only related to those channel codes received in error. Through this method, it can achieve adjustments for the current round of transmission. Performance analyses and simulation results show that the proposed optimization scheme is more energy efficient than any other schemes of interest under the condition of meeting the requirement of transmission reliability.
Autors: Xingcheng Liu;Wei Li;Feng Han;Yi Xie;
Appeared in: IEEE Sensors Journal
Publication date: Sep 2017, volume: 17, issue:18, pages: 6119 - 6128
Publisher: IEEE
 
» An RS-GIS-Based ComprehensiveImpact Assessment of Floods—A Case Study in Madeira River, Western Brazilian Amazon
Abstract:
Geographical information systems-based methods can be handled as powerful tools in assessing and quantifying impacts and, thus, supporting strategies for disaster risk reduction (DRR). This is particularly relevant on scenarios of global climate change and intensified increased human interventions on riverine systems. The Madeira River in Porto Velho city (Brazilian Amazon) is a good example of susceptible area to both of these factors. We take advantage of the 2014 flood, the largest recorded for this region, for combining remote sensing and geographic information system with socio, health, and infrastructure data to quantify spatially the flood impacts. Using high resolution airborne images, we applied a machine learning classification algorithm for detecting urban areas. Our results show that at the flood extent related to the highest river level at least 0.65 of urban area, 87 km of urban streets, four public schools, and two public health units were affected. More than 16 800 people suffered the impacts directly, and children represented 29.7% of them. Based on registered data, it was quantified that the city registered more than 20 cases of leptospirosis and the truck flow on the region decreased up to 92%. The spatially-explicit results of this letter are potential to guide strategies aiming to support decision-making for DRR.
Autors: Leonardo B. L. Santos;Tiago Carvalho;Liana O. Anderson;Conrado M. Rudorff;Victor Marchezini;Luciana R. Londe;Silvia M. Saito;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Sep 2017, volume: 14, issue:9, pages: 1614 - 1617
Publisher: IEEE
 
» An Ultra-Low-Power Dual-Polarization Transceiver Front-End for 94-GHz Phased Arrays in 130-nm InP HBT
Abstract:
We present a fully integrated 94-GHz transceiver front-end in a 130-nm/1.1-THz InP HBT process. Low power is obtained through low-voltage design and high transistor gain. The IC is designed for multi-function, dual-polarization phased arrays. At 1.5-V collector bias, in dual-polarization simultaneous receiving mode, the IC has 21-dB gain, <9.3-dB noise figure, and consumes 39 mW, while in transmitting mode with time-duplexed vertical and horizontal outputs, the transceiver front-end achieves 5-dBm output power, 22-dB gain, and consumes 40 mW. At 1-V collector bias, in dual-polarization simultaneous receiving mode, the IC has 22.7-dB gain, <8.9-dB noise figure, and consumes 26 mW, while in transmitting mode, it has 22-dB gain and the saturated output power of 1.4 dBm with 29-mW power consumption.
Autors: Seong-Kyun Kim;Robert Maurer;Arda Simsek;Miguel Urteaga;Mark J. W. Rodwell;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2017, volume: 52, issue:9, pages: 2267 - 2276
Publisher: IEEE
 
» Analog to Stochastic Bit Stream Converter Utilizing Voltage-Assisted Spin Hall Effect
Abstract:
We introducea spintronic analog to stochastic bit stream (SBS) converter (ASC) based on a three terminal magnetic tunnel junction (MTJ) with a heavymetal layer. The critical current of the spin Hall effect (SHE) for switching the MTJ is efficiently modulated by applying a voltage across the MTJ via the voltage-controlled magnetic anisotropy effect. This effect results in the switching probability linearly depending on the amplitude of the analog input signal of the ASC. There are several advantages of using the voltage-assistedSHE for generating an SBS. The stochastic switching behavior of MTJ devices drastically reduces the area overhead by simplifying control circuits in the ASC. Moreover, the voltage-assisted SHE switching improves energy efficiency over traditional spin transfer torque (STT)-based MTJ switching by diminishing ohmic dissipation. Also, multiple MTJs on a single heavy metal layer increases the bandwidth by simultaneously converting analog input signals to SBSs. The performance of the spintronic ASC was evaluated by using the macrospin three terminal MTJ compactmodel integrated into a 45-nm CMOS technology. The proposed ASC can achieve 7x reduction in power consumption comparedto the previousSTT-basedwork and significant improvement in area-efficiency compared with the pure CMOS-based design.
Autors: H. Lee;A. Lee;F. Ebrahimi;P. Khalili Amiri;K. L. Wang;
Appeared in: IEEE Electron Device Letters
Publication date: Sep 2017, volume: 38, issue:9, pages: 1343 - 1346
Publisher: IEEE
 
» Analysis and Design of a Thermoelectric Energy Harvesting System With Reconfigurable Array of Thermoelectric Generators for IoT Applications
Abstract:
In this paper, a novel thermoelectric energy harvesting system with a reconfigurable array of thermoelectric generators (TEGs), which requires neither an inductor nor a flying capacitor, is proposed. The proposed architecture can accomplish maximum power point tracking (MPPT) and voltage conversion simultaneously via the reconfiguration of the TEG array, and demonstrate significantly improved power conversion efficiency over the conventional switching converter and switched-capacitor architectures. Two systematical scaling approaches—powers-of-two scaling and maximum-factor scaling—are presented and analyzed to serve as the design guideline, catering for reconfigurable TEG arrays of different sizes. In order to optimize the chip area required, a custom-designed, multi-level hierarchy and systematically scalable switch array that requires a reasonable number of switches is also developed to enable the reconfiguration of the TEG array. The 16-node and 12-node versions of the proposed system have been implemented in a standard 0.35- CMOS process. Measurement results verify the analysis, and confirm that the proposed system can maintain a higher than 88.8% efficiency over a wide range of temperature gradients.
Autors: Qiping Wan;Ying-Khai Teh;Yuan Gao;Philip K. T. Mok;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Sep 2017, volume: 64, issue:9, pages: 2346 - 2358
Publisher: IEEE
 
» Analysis and Design of Continuous-Time Delta–Sigma Converters Incorporating Chopping
Abstract:
Chopping the operational transconductance amplifier (OTA) of the input integrator in a CT is a traditional and effective way of addressing flicker noise in such modulators. Unfortunately, chopping leads to aliasing of shaped quantization noise into the signal band and degrades performance. We analyze the mechanisms of shaped-noise aliasing in OTA- integrators that use two-stage feedforward-compensated OTAs, and show that aliasing can be largely mitigated by using an finite impulse response feedback digital-to-analog converter with its zeros placed at multiples of twice the chopping frequency. The theory is borne out by measurement results from a single-bit CT, which achieves a peak SNDR of 98.5 dB in a 24-kHz bandwidth while consuming only 280 from a 1.8-V supply. Realized in a 180-nm CMOS technology, it achieves a noise corner of about 3 Hz when chopped at .
Autors: Sujith Billa;Amrith Sukumaran;Shanthi Pavan;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2017, volume: 52, issue:9, pages: 2350 - 2361
Publisher: IEEE
 
» Analysis and Design of Improved Weighted Average Current Control Strategy for LCL-Type Grid-Connected Inverters
Abstract:
The LCL grid-connected inverter has the ability to attenuate the high-frequency current harmonics. However, the inherent resonance of the LCL filter affects the system stability significantly. To damp the resonance effect, the dual-loop current control can be used to stabilize the system. The grid current plus capacitor current feedback system is widely used for its better transient response and high robustness against the grid impedance variations. The weighted average current (WAC) feedback scheme is capable to provide a wider bandwidth at higher frequencies but show poor stability characteristics under weak grid scenarios. To overcome this shortcoming, the improved WAC damping method is proposed with an additional capacitor current feedback loop. In this paper, a systematic parameter design guideline for the optimal selection of the current loop proportional resonant controller and the additional capacitor current feedback coefficient are presented for the improved WAC feedback control strategy. The satisfactory range of the system control parameters can be obtained under different delay conditions to meet the system performance specifications. The improved WAC method enhances system robustness under weak grid scenarios, and the stability and robustness have been enhanced under control delay. Finally, the experimental results are presented to validate the effectiveness of the proposed improved WAC control strategy and the parameter design method.
Autors: Yang Han;Zipeng Li;Ping Yang;Congling Wang;Lin Xu;Josep M. Guerrero;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2017, volume: 32, issue:3, pages: 941 - 952
Publisher: IEEE
 
» Analysis of a MEMS Tuned Cavity Oscillator on $X$ -Band
Abstract:
This paper reports on the analysis of a radio frequency microelectromechanical systems (RF-MEMS) tuned cavity oscillator on -band based on a GaN-HEMT monolithic microwave integrated circuit reflection amplifier. The RF-MEMS-switches are mounted on a low-loss printed circuit board (PCB) intruded in an aluminum cavity that is coupled to a microstrip line connected to the reflection amplifier. This paper investigates the influence of the number of switches as well as their positions with respect to phase noise and tuning range. Vertical and horizontal positions of the switches are varied with target on optimum trade-off between phase noise and total tuning range. For a three-row MEMS-configuration at 1-mm depth from the end cavity wall, a tuning range of 4.9% is measured. The center frequencies are ranging from 9.84 to 10.33 GHz with measured phase noise of −140 to −129 dBc/Hz at 100-kHz offset. A similar three-row MEMS setup at 2.5-mm depth provides a tuning range of 12.3% with measured phase noise of −133 to −123 dBc/Hz at 100-kHz offset.
Autors: Mikael Hörberg;Thomas Emanuelsson;Herbert Zirath;Dan Kuylenstierna;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Sep 2017, volume: 65, issue:9, pages: 3257 - 3268
Publisher: IEEE
 
» Analysis of a Novel Metal Implant Junctionless Tunnel FET for Better DC and Analog/RF Electrostatic Parameters
Abstract:
Steep rise in the subthreshold slope, high current driving capability, and negligible ambipolarity are the major prerequisite conditions of tunnel FETs (TFETs) to make it applicable for Analog/RF circuit applications. Along with that, fabrication of physically doped TFETs is a major concern in device technology. In this context, this paper deals with junctionless TFET with a metal implanted in the oxide at the source/channel and drain/channel junctions to enhance its ON-current and reduce the ambipolar nature. The metal introduced at the source/channel junction generates abruptness and brings improvement in subthreshold slope, which increases the current driving capability of the device. Similarly, the metal implanted at the drain/channel junction widens the energy gap at the same junction to reduce the ambipolar behavior of the device. This also contributes to the enhancement of dc and analog/RF performance of the device. The selection of appropriate work function and length of the metal implanted at both the interfaces is important to maintain the improved ON-current and ambipolarity. This optimization gives idea of keeping the appropriate length, which provides direction toward practical feasibility at the experimental level.
Autors: Sukeshni Tirkey;Dheeraj Sharma;Dharmendra Singh Yadav;Shivendra Yadav;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3943 - 3950
Publisher: IEEE
 
» Analysis of a Novel Stator Construction Employing Steel Wire in Place of Laminations
Abstract:
This paper examines a novel method of constructing large diameter generators using many layers of steel wire in place of laminations. The stator coreback is formed by winding thin steel wire around the outside of the armature coils and then encapsulating the structure in epoxy. This technique simplifies the manufacturing process by removing the requirement to build a large support structure to carry the laminations. The electromagnetic behavior of a wire coreback is very different from traditional laminations, however, and produces abrupt changes in flux density across its thickness. The material is difficult to model using conventional FEA techniques due to the large number of elements required to mesh the small diameter wire. This paper examines two alternative modeling approaches. Method 1 uses two-dimensional (2-D) FEA to model the steel wire as a lamination oriented in the “wrong” direction. Method 2 uses a quasi-analytic approach based on detailed 3-D FE analysis of a small section of the generator to capture the flux density profile in the airgap. The two models are benchmarked against a prototype generator tested in the laboratory, and it is shown that the quasi-analytical technique gives the most accurate prediction of performance.
Autors: Nick Stannard;Richard Martin;Glynn J. Atkinson;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2017, volume: 32, issue:3, pages: 993 - 1001
Publisher: IEEE
 
» Analysis of Atomistic Dopant Variation and Fermi Level Depinning in Nanoscale Contacts
Abstract:
Using quantum transport simulations of metal–semiconductor junctions, we assess the viability of barrier thinning with dopants and barrier lowering with interfacial layers as solutions for contact resistivity in nanoscale transistors. Our atomistic simulations show that the discreteness of dopants leads to increasing variability in contact resistance as dimensions scale below 10 nm. We find that the use of interlayers can counteract low doping caused by atomistic variation, but the interlayer must have band edge Fermi level pinning to provide a net reduction in contact resistivity. For materials with low doping limits, such as n-type germanium, we find that interlayer contacts still have difficulty meeting resistivity targets.
Autors: Gautam Shine;Krishna C. Saraswat;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3768 - 3774
Publisher: IEEE
 
» Analysis of Fundamental-Mode Beam Transport in Highly Multimode Fibers
Abstract:
In view of the growing demand for fiber beam delivery in manufacturing systems with close to diffraction-limited beam quality, we present an analysis of the propagation of a nearly diffraction-limited laser beam through 5 to 10 m long multimode step-index fibers with a numerical aperture of 0.111 and core diameters of up to 80 μm. The influence of the launching conditions are investigated theoretically and experimentally by varying the beam size of the input beam. At a core diameter as high as 80 μm, corresponding to a mode field area of 2800 μm2, and an optimum launching condition, the transmitted M2 was measured to be around 1.3. It is shown that bending of the fibers down to radii as small as 2 cm barely influences the beam quality factor of the transmitted beam for all the tested fibers as the M2 was always found to be smaller than 1.5. The threshold of stimulated Raman scattering was measured to be around 60 kW for a fiber loosely placed on the table (rbend ≥ 25 cm) with a total length of 10 m and a core diameter of 80 μm.
Autors: Christian Röhrer;Götz Kleem;Marwan Abdou Ahmed;Thomas Graf;
Appeared in: Journal of Lightwave Technology
Publication date: Sep 2017, volume: 35, issue:17, pages: 3637 - 3642
Publisher: IEEE
 
» Analysis of Output Loading Effects in Autonomous Circuits
Abstract:
A methodology is presented to analyze the impact of the termination load on the oscillation frequency and output power of autonomous circuits. Variations of this load can also lead to an extinction of the oscillation signal, due to their effect on the impedance seen by the active device(s). The new methodology enables an efficient analysis and mitigation of the pulling effects, in the case of undesired output mismatch, as well as an efficient oscillator synthesis in large-signal conditions, for specified values of oscillation frequency and output power. The method is based on the calculation of constant-amplitude and constant-frequency contours, traced in the Smith chart. Oscillation extinctions and some forms of hysteresis can be predicted through the inspection of these contours. However, the stability properties will generally depend on the frequency characteristic of the termination impedance. In an oscillator synthesis, the selected impedance, providing the specified values of oscillation frequency and output power, must be implemented in order to guarantee a stable solution. The dependence of the phase-noise spectral density on the particular implementation is predicted, combining an analysis based on the variance of the phase deviation with the conversion-matrix approach.
Autors: Almudena Suárez;Mabel Pontón;Sergio Sancho;Franco Ramírez;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Sep 2017, volume: 65, issue:9, pages: 3135 - 3146
Publisher: IEEE
 
» Analysis of Saturated Belief Propagation Decoding of Low-Density Parity-Check Codes
Abstract:
We consider the effect of log-likelihood ratio saturation on the belief-propagation decoding of low-density parity-check codes. Saturation is commonly done in practice and is known to have a significant effect on the error-floor performance. Our focus is on threshold analysis and the stability of density evolution. We analyze the decoder for standard low-density parity-check code ensembles and show that belief-propagation decoding generally degrades gracefully with saturation. Stability of density evolution is, on the other hand, rather strongly affected by saturation, and the asymptotic qualitative effect of saturation is similar to reduction by one of variable-node degree. We also describe conditions under which the block-error threshold for saturated belief-propagation decoding equals the bit-error threshold.
Autors: Shrinivas Kudekar;Tom Richardson;Aravind R. Iyengar;
Appeared in: IEEE Transactions on Information Theory
Publication date: Sep 2017, volume: 63, issue:9, pages: 5734 - 5751
Publisher: IEEE
 
» Analysis of the Impact of Microgrid Penetration on Power System Dynamics
Abstract:
The paper proposes a stochastic model to analyse the dynamic coupling of the transmission system, the electricity market, and microgrids. The focus is on the impact of microgrids on the transient response of the system and, in particular, on frequency variations. Extensive Monte Carlo simulations are performed on the IEEE 39-bus system, and show that the dynamic response of the transmission system is affected in a nontrivial way by both the number and the size of the microgrids.
Autors: Pietro Ferraro;Emanuele Crisostomi;Marco Raugi;Federico Milano;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2017, volume: 32, issue:5, pages: 4101 - 4109
Publisher: IEEE
 
» Analysis of the Magnetostatic Energy of Chains of Single-Domain Nanomagnets for Logic Gates
Abstract:
Nanomagnet logic (NML) circuits are magnetic field-coupled interacting structures built up from nanoscaled magnets to perform logic operations. The bistable character of nanomagnets’ magnetization is associated with “0” and “1” logic states, which may be used to perform Boolean operations. In this paper, we first investigate the limits of single-domain magnetic structure in modeling the magnetostatic energy of particles of several polyhedron shapes. The model, which is based on the evaluation of multidimensional integrals through the Monte Carlo method, includes the demagnetizing energy of individual magnetic specimens and the dipolar coupling between two or more nanomagnets. The accuracy and the limits of the model are evaluated through comparison with a well-established numerical micromagnetic solver. The magnetostatic behavior for several configurations of horizontal chain of interacting nanomagnets (NML wire) is investigated. Rectangular nanomagnets present weak dipolar antiferromagnetic (AF) coupling that may result in error during information propagation across the chain. We examine a novel wire structure formed by a sequence of different slanted nanomagnets that yield strong dipolar coupling. For this system, error during information propagation is very unlikely, since the magnetic energy of the particles has single global minima corresponding to stable AF alignment. The proposed model can be readily applied as a tool for the study of advanced NML circuits and systems.
Autors: Luiz G. C. Melo;Thiago R. B. S. Soares;Omar P. Vilela Neto;
Appeared in: IEEE Transactions on Magnetics
Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 10
Publisher: IEEE
 
» Analysis of the Performance Enhancement of MIMO Systems Employing Circular Polarization
Abstract:
The advantages of adopting circular polarization in multiple-input-multiple-output (MIMO) systems are illustrated for both line-of-sight (LOS) and multipath propagation. More in detail, an analysis of the MIMO performance attainable by employing orthogonal circularly polarized (CP) radiators with respect to orthogonal linearly polarized (LP) ones, has been addressed. At first, an accurate analysis is presented aimed at the evaluation of the channel matrix by comprehensively including also the effects of the antenna in LOS condition. In particular, the channel matrix has been calculated as a function of the antenna parameters and orientation, demonstrating that CP radiators are capable of obtaining better average values of the matrix eigenvalues with respect to LP ones. The analysis is therefore completed by evaluating the characteristics of a CP MIMO system operating in indoor environment representing this latter a more challenging condition where multipath propagation occurs. In this latter case, some meaningful numerical experiments have been performed by using a reliable ray-tracing solver, followed by a measurements campaign conducted in a real environment for validation purposes. Measurements, which are in good agreement with simulations, confirm the benefits of adopting circular polarization in MIMO systems with respect to LP.
Autors: Francesco Alessio Dicandia;Simone Genovesi;Agostino Monorchio;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2017, volume: 65, issue:9, pages: 4824 - 4835
Publisher: IEEE
 
» Analysis of Time-Series Spectral Index Data to Enhance Crop Identification Over a Mediterranean Rural Landscape
Abstract:
Spectral index time series can provide valuable phenological information into the classification process for the precise crop mapping, in order to reduce misclassification rates associated with low interclass and high intraclass spectral variability. Stochastic hidden Markov models (HMMs) are efficient yet computationally demanding classification approach which can simulate crop dynamics, exploiting the spectral information of their phenological states and the relations between these states. This letter aims to present a methodology which achieves accurate classification results while maintaining a low computational cost. A classification framework based on HMMs was developed, and different spectral indices were generated from the time series of Landsat ETM+ and RapidEye imagery, for modeling crop vegetation dynamics over a Mediterranean rural area, with high spatiotemporal crop heterogeneity. To further improve the HMMs indices classification, separability analysis and two different decision fusion strategies were tested. The assessment of the classification accuracy, along with an evaluation of the computational cost, indicated that the green-red vegetation index produced the most favorable results among the individual spectral indices. Although the decision fusion based on an integration of a reliability factor increased the overall accuracy by 3.1%, this came at the cost of computational time, compared to the separability analysis model which required less processing time.
Autors: Sofia Siachalou;Giorgos Mallinis;Maria Tsakiri-Strati;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Sep 2017, volume: 14, issue:9, pages: 1508 - 1512
Publisher: IEEE
 
» Analysis of Wideband Circularly Polarized Ferrite-Loaded Antenna Based on Unidirectional Resonant Modes
Abstract:
We propose a wideband circularly polarized antenna that consists of a metallic patch and some parasitically coupled elements mounted on a grounded dielectric-ferrite substrate. The metallic patch is fed by a proximity-coupled feed line placed between the ferrite and the dielectric layers. The parasitically coupled elements are included to improve the impedance bandwidth of antenna and are excited through the metallic patch. The antenna utilizes the resonant modes of the structure, which rotate only in the clockwise or counter-clockwise direction. A semi-analytical solution based on the magnetic wall approximation shows that the resonance frequencies of the clock- and counter-clockwise resonant modes differ significantly when operating in the frequency range where the effective permeability of the ferrite layer is negative. Moreover, there is a good agreement between the model presented and full-wave numerical simulations. For the proposed antenna, the results show that the radiation bandwidth is more than 15.5% and the 3 dB axial ratio bandwidth is more than 50%. The proposed antenna is easy to design and fabricate, does not require a complicated feeding network, and has a wideband and wide-angle circular polarization.
Autors: M. Mashhadi;B. Rejaei;N. Komjani;J. Ghalibafan;
Appeared in: IEEE Transactions on Magnetics
Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 8
Publisher: IEEE
 
» Analysis on Ensemble of Regenerating Codes and Replication
Abstract:
This letter studies the performance of ensemble of Regenerating codes and Replication (RR). It theoretically analyzes the storage-bandwidth tradeoff curve of RR, and attains two extremal cases, corresponding to minimum storage cost RR (MSRR) and minimum repair bandwidth RR (MBRR), respectively. Compared with the case of independently applying regenerating codes, the evaluation results indicate, with extra storage cost, MSRR has better average repair bandwidth and average disk I/O, and MBRR has less average disk I/O cost and almost the same level of average repair bandwidth, i.e., when satisfying the data available probability , MSRR achieves at least 5.6% and 50%, and MBRR achieves at least 23.7% and 1.3% less disk I/O and repair bandwidth consumption in evaluation data sets, respectively.
Autors: Zimu Yuan;Huiying Liu;
Appeared in: IEEE Communications Letters
Publication date: Sep 2017, volume: 21, issue:9, pages: 1901 - 1904
Publisher: IEEE
 
» Analytical Calculation and Optimization of Magnetic Field in Spoke-Type Permanent-Magnet Machines Accounting for Eccentric Pole-Arc Shape
Abstract:
This paper presents an analytical method for calculating and optimizing magnetic field in spoke-type permanent-magnet machines accounting for eccentric pole-arc shape. Normalized flux density is derived from conformal transformation taking into account eccentric pole-arc shape, and final field solution is predicted according to the flux continuity theorem. The optimal results show the harmonic content of flux density can be reduced a lot by optimizing eccentric distance of eccentric pole arc while fundamental content will reduce a little. The proposed analytical solution on prototype machines is implemented. The finite element (FE) and experimental results confirm that the developed analytical method has high accuracy for predicting and optimizing magnetic field.
Autors: Yu Zhou;Huaishu Li;Ningning Ren;Zhiqiang Xue;Yingsan Wei;
Appeared in: IEEE Transactions on Magnetics
Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 7
Publisher: IEEE
 
» Analytical Drain Current Model for Amorphous InGaZnO Thin-Film Transistors at Different Temperatures Considering Both Deep and Tail Trap States
Abstract:
Surface-potential-based drain current model is presented for amorphous InGaZnO thin-film transistors considering both exponential deep and tail trap states densities in the energy gap. The trap states densities are determined by the numerical calculation on the basis of the assumption that the trapped carrier concentration is much higher than the free carrier concentration. The analytical drain current model is developed consistent with the numerical calculation, and verified by the experimental data at different temperatures.
Autors: Hongyu He;Yuan Liu;Binghui Yan;Xinnan Lin;Xueren Zheng;Shengdong Zhang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3654 - 3660
Publisher: IEEE
 
» Analytical Drain Current Model of 1-D Ballistic Schottky-Barrier Transistors
Abstract:
A new analytical model based on the Wentzel–Kramers–Brillouin approximation for MOSFET-like 1-D ballistic transistors with Schottky-Barrier contacts has been developed for the drain current. By using a proper approximation of both the Fermi–Dirac distribution function and transmission probability, an analytical solution for the Landauer integral was obtained, which overcomes the limitations of existing models and extends their applicability toward high bias voltages needed for analog applications. The simulations of transfer and output characteristics are found to be in agreement with the experimental data for sub-10-nm carbon-nanotube FETs.
Autors: Igor Bejenari;Michael Schröter;Martin Claus;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2017, volume: 64, issue:9, pages: 3904 - 3911
Publisher: IEEE
 

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