Electrical and Electronics Engineering publications abstract of: 09-2016 sorted by title, page: 0

» "Let's Protest": Surprises in Communicating Against Repression
Abstract:
In Egypt in June 2010, a young man named Khaled Said was beaten to death by the secret police. In response, Google executive Wael Ghonim set up the Facebook page "We are all Khaled Said," and within a day, tens of thousands of people had joined. The Facebook page was used to publicize a series of protests against police brutality and government corruption, including a huge protest on 25 January 2011. As the resistance gathered momentum, Egyptian president Hosni Mubarak ordered Internet and mobile phone service be shut down.
Autors: Brian Martin;
Appeared in: IEEE Potentials
Publication date: Sep 2016, volume: 35, issue:5, pages: 16 - 18
Publisher: IEEE
 
» 1-kW 2000–4500 r/min Ferrite PMSM Drive: Comprehensive Characterization and Two Sensorless Control Options
Abstract:
An optimal design of internal Ferrite permanent-magnet motor with embedded key finite-element method verification is presented with the scope to increase the efficiency of the small power motors without using expensive rare earth permanent magnets. Two internal flux concentration topologies are analyzed, and the geometric dimensions and performances are presented for three cases, all at 1-kW rated power at 4500 r/min rated speed. The 6/8 poles ferrite-spoke permanent-magnet synchronous motor prototype was built and test results prove an efficiency larger than 88% for a large load range. Two sensorless control methods based on active flux observer are presented, with the key simulation results including acceleration, speed reversal, loading, and unloading speed responses.
Autors: Flavio J. H. Kalluf;Andy S. Isfănuţi;Lucian N. Tutelea;Ana Moldovan-Popa;Ion Boldea;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Sep 2016, volume: 52, issue:5, pages: 3980 - 3989
Publisher: IEEE
 
» 1-port Measurement Method of the Coupling Factor and Receiver for Spatial and State Freedom in Wireless Power Transfer Systems
Abstract:
For spatial and state freedom in wireless power transfer (WPT) systems, the coupling factor and receiver have been estimated, using a loop current flowing into the transmitting coil by 1-port measurement method. Since the power transfer efficiency is related to the coupling factor and the load impedance, it is required to estimate and analyze them. In strongly and loosely coupled regions, the proposed measurement method can evaluate the location and battery states of the receiver by tracking the operating frequency of the transmitter. Compared to the calculated results obtained by conventional 2-port measurements against the between the transmitting and receiving coils and the receiver , the proposed 1-port estimation method for frequency-tuned WPT systems is relatively simple and efficient, and has been experimentally verified.
Autors: Hyeong-Seok Jang;Jong-Won Yu;Wang-Sang Lee;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2016, volume: 64, issue:9, pages: 4098 - 4102
Publisher: IEEE
 
» 1.23-ns Pulsewidth of Quenched High Gain GaAs Photoconductive Semiconductor Switch at 8-nJ Excitation
Abstract:
In this letter, we show that the quenched high gain (HG) operation of gallium arsenide photoconductive semiconductor switches can be achieved with an excitation energy as low as 8 nJ. The minimum pulse width of 1.23 ns is obtained and the corresponding bias electric field is 71.8 kV/cm. The concept of an avalanche gain is proposed to verify that the avalanche level is remained in the quenched HG operation.
Autors: Ming Xu;Ruibing Li;Cheng Ma;Wei Shi;
Appeared in: IEEE Electron Device Letters
Publication date: Sep 2016, volume: 37, issue:9, pages: 1147 - 1149
Publisher: IEEE
 
» 2-D Analytical Model for External Rotor Brushless PM Machines
Abstract:
This paper presents a 2-dimensional analytical model for external rotor brushless machines with surface mounted magnets. The subdomain technique is used to divide the problem into magnets, airgap, slot-openings, and slots regions. The magnetic flux density distributions are initially calculated, and then the important quantities of the machine such as back electromotive force, cogging torque, electromagnetic torque, self- and mutual-inductances, and unbalanced magnetic forces are computed. The finite-element method and experimental results are used to confirm the validity of the proposed model.
Autors: H. Moayed-Jahromi;Akbar Rahideh;Mohammad Mardaneh;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2016, volume: 31, issue:3, pages: 1100 - 1109
Publisher: IEEE
 
» 2-D Threshold Voltage Model for the Double-Gate p-n-p-n TFET With Localized Charges
Abstract:
In this paper, for the first time, we developed an analytical model for the surface potential of the double-gate p-n-p-n tunneling field-effect transistors (TFETs) considering the effect of localized charges at the Si-SiO2 interface near the source-channel junction. From the surface potential model, the minimum tunneling width is then evaluated and is used to extract the threshold voltage using the constant-current method. The model can be applied to study the effect of localized charges on the threshold voltage of the p-n-p-n TFETs as it captures the shift in the threshold voltage due to the change in the localized charge region length, localized charge density, and polarity. The accuracy of the proposed model is verified using 2-D Technology Computer-Aided Design simulations.
Autors: Dawit Burusie Abdi;Mamidala Jagadesh Kumar;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2016, volume: 63, issue:9, pages: 3663 - 3668
Publisher: IEEE
 
» 2016 Fellows Elevation and Recognition
Abstract:
Lists MTTS society members who were elevated to the status of IEEE Fellow for 2016.
Autors: Michael Steer;
Appeared in: IEEE Microwave Magazine
Publication date: Sep 2016, volume: 17, issue:9, pages: 45 - 57
Publisher: IEEE
 
» 3-D Particle-in-Cell Simulations on a Novel High-Power and High-Efficiency Coaxial Triode Vircator
Abstract:
In order to improve the efficiency and obtain high output power with pure mode, 3-D particle-in-cell simulations are made on a novel coaxial triode vircator. Simulation results show that due to the appearance of the additional cylindrical cathode rod along the centerline, pure TM01 mode can be obtained in the output region. Simulation results also show that high-efficiency and pure TM01 mode output maintains even for output waveguide radius (equals anode radius) somewhat larger than the cutoff radius of the TM02 mode (). When the cathode and anode gap keeps unchanged, most optimal structure values can be scaled for models with different anode radius. By careful optimizations, the efficiency can reach 15% at an output power of 1.7 and 2.2 GW, respectively, for anode radii equal 5.6 and 6.6 cm (); For anode radii equal 7.6 and 8.6 cm (), the efficiency is about 13% at an output power of 2.5 and 2.9 GW, respectively. The operating frequencies all are about 3.6 GHz.
Autors: Wenyuan Yang;Zhiwei Dong;Ye Dong;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2016, volume: 63, issue:9, pages: 3713 - 3718
Publisher: IEEE
 
» 3C-SiC Transistor With Ohmic Contacts Defined at Room Temperature
Abstract:
Among all SiC polytypes, only 3C-SiC has a cubic structure and can be hetero-epitaxial grown on large area Si substrate, thus providing an alternative choice for fabricating cheap wide bandgap power devices. Here, we present a low resistivity ( cm ohmic contact formed by directly depositing a Ti/Ni metal stack on n-type 3C-SiC without any extra annealing. For the first time, 3C-SiC lateral MOSFETs with as-deposited ohmic contacts were fabricated, and it turned out not only the ohmic contact is free from any interface voids, but also a higher field-effect mobility value ( cm/V s) was achieved compared with the annealed devices.
Autors: Fan Li;Yogesh Sharma;David Walker;Steven Hindmarsh;Mike Jennings;David Martin;Craig Fisher;Peter Gammon;Amador Pérez-Tomás;Phil Mawby;
Appeared in: IEEE Electron Device Letters
Publication date: Sep 2016, volume: 37, issue:9, pages: 1189 - 1192
Publisher: IEEE
 
» 3D Modeling from Photos Given Topological Information
Abstract:
Reconstructing 3D models given a single-view 2D information is inherently an ill-posed problem and requires additional information such as shape prior or user input.We introduce a method to generate multiple 3D models of a particular category given corresponding photographs when the topological information is known. While there is a wide range of shapes for an object of a particular category, the basic topology usually remains constant.In consequence, the topological prior needs to be provided only once for each category and can be easily acquired by consulting an existing database of 3D models or by user input. The input of topological description is only connectivity information between parts; this is in contrast to previous approaches that have required users to interactively mark individual parts. Given the silhouette of an object and the topology, our system automatically finds a skeleton and generates a textured 3D model by jointly fitting multiple parts. The proposed method, therefore, opens the possibility of generating a large number of 3D models by consulting a massive number of photographs. We demonstrate examples of the topological prior and reconstructed 3D models using photos.
Autors: Young Min Kim;Junghyun Cho;Sang Chul Ahn;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Sep 2016, volume: 22, issue:9, pages: 2070 - 2081
Publisher: IEEE
 
» 5 GHz CMOS Quadrature VCO Using Trifilar-Transformer-Coupling Technology
Abstract:
A trifilar-transformer-coupling quadrature voltage-controlled oscillator (TTC-QVCO) with dual transformer- feedback technology is proposed. Compared to traditional QVCOs, the proposed TTC-QVCO provides an additional coupling path, and therefore achieves an improved quadrature phase accuracy, a lower phase noise and a wider tuning range. The TTC-QVCO, implemented in a 0.18- CMOS technology, exhibits a frequency tuning range of 19.6% centered at 5.4 GHz and a power consumption of 5.4 mW from a 1.35 V supply voltage. The QVCO has a measured phase noise of −120.42 dBc/Hz at 1-MHz offset and quadrature phase error of less than 2° with a FoMT of 194.3 dB.
Autors: Kuang-Wei Cheng;Yan-Ru Tseng;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Sep 2016, volume: 26, issue:9, pages: 717 - 719
Publisher: IEEE
 
» 55-nm SiGe BiCMOS Distributed Amplifier Topologies for Time-Interleaved 120-Gb/s Fiber-Optic Receivers and Transmitters
Abstract:
Two distributed circuits based on MOS-HBT cascodes are reported in a 55-nm SiGe BiCMOS technology and are aimed at a single-chip time-interleaved transceiver for future 1-Tb/s optical links. The first, a DC-135-GHz single-ended distributed amplifier (DA) was optimized for low noise, linear receivers, and has a measured noise figure (NF) 7 dB up to 88.5 GHz, 800 mVpp of linear input range, and 8.5 dB gain. Operation was confirmed with PRBS-31 eye diagram measurements up to 120 Gb/s. Additionally, a novel time-interleaved distributed power DAC test circuit was implemented as a proof-of-concept to investigate the maximum achievable output bandwidth at a differential output voltage swing of 6 Vpp, as needed to directly drive an optical modulator. Simulations of the doubly segmented 6-bit DAC show 4-PAM output eye diagrams at up to 120 GBaud. The measured clock-input-to-data-output small-signal bandwidth is 65 GHz. When the DAC is measured as a switching large-swing driver, the differential output voltage swing remains larger than beyond 50 Gb/s. Time interleaving of 4 thermometer MSBs is demonstrated experimentally to form a 1.8- differential, 10-GBaud 3-PAM output signal. The experimental sampling rate is limited to 10 GS/s by the capacitance and bandwidth of the low-frequency probes and pads used for the data lanes.
Autors: James Hoffman;Stefan Shopov;Pascal Chevalier;Andreia Cathelin;Peter Schvan;Sorin P. Voinigescu;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2016, volume: 51, issue:9, pages: 2040 - 2053
Publisher: IEEE
 
» 5G transport networks: the need for new technologies and standards
Abstract:
Mobile transport networks will play a vital role in future 5G and beyond networks. In particular, access transport networks connecting radio access with core networks are of critical importance. They will be required to support massive connectivity, super high data rates, and real-time services in a ubiquitous environment. To attain these targets, transport networks should be constructed on the basis of a variety of technologies and methods, depending on application scenarios, geographic areas, and deployment models. In this article, we present several technologies, including analog radio-over-fiber transmission, intermediate-frequency- over-fiber technology, radio-on-radio transmission, and the convergence of fiber and millimeter-wave systems, that can facilitate building such effective transport networks in many use cases. For each technology, we present the system concept, possible application cases, and demonstration results. We also discuss potential standardization and development directions so the proposed technologies can be widely used.
Autors: Pham Tien Dat;Atsushi Kanno;Naokatsu Yamamoto;Tetsuya Kawanishi;
Appeared in: IEEE Communications Magazine
Publication date: Sep 2016, volume: 54, issue:9, pages: 18 - 26
Publisher: IEEE
 
» 60-GHz CMOS Current-Combining PA With Adaptive Back-Off PAE Enhancement
Abstract:
This brief describes the design and implementation of a current-combining power amplifier (PA) with a fully adaptive approach to enhance the output power and the back-off power-added efficiency (PAE). The PA consists of a main amplifier and an auxiliary amplifier. Adaptive biasing technique is employed to shut down or provide optimum bias voltage to the auxiliary amplifier according to the input power level. The 50- input matching is realized with adaptive power distribution. The output load modulation is accomplished by a compact output matching network (MN) using transmission lines and transformers. Based on the same MN, the back-off PAE degradation caused by the low output impedance of the auxiliary path is mitigated. The proposed PA is designed at 60 GHz using 65-nm CMOS and is experimentally characterized. The measurement results reveal 16-dBm OP1dB and 14% peak PAE. Approximately 8% PAE at 6-dB back-off is achieved, addressing improved back-off efficiency.
Autors: Haiwei Zhang;Quan Xue;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Sep 2016, volume: 63, issue:9, pages: 823 - 827
Publisher: IEEE
 
» -Band High-Efficiency Metamaterial Microwave Sources
Abstract:
In this paper, we present an S-band compact metamaterial microwave source, which is based on a rectangular output coupler and a new all-metal metamaterial slow-wave structure that has been proposed previously. Due to the reversed Cherenkov radiation of the metamaterial, this metamaterial microwave source can be considered as a new sort of backward wave oscillators (BWOs). The S-band metamaterial microwave source has been further studied and analyzed by using Ansoft HFSS and CST Particle studio particle-in-cell solver. The simulated results show that the electronic efficiency of this S-band metamaterial microwave source can go up to 90% with the peak output power of 4.5 MW. When compared with conventional BWOs, it has obvious advantages such as miniaturization and high electronic efficiency.
Autors: Yanshuai Wang;Zhaoyun Duan;Fei Wang;Shifeng Li;Yan Nie;Yubin Gong;Jinjun Feng;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2016, volume: 63, issue:9, pages: 3747 - 3752
Publisher: IEEE
 
» -Player Statistical Nash Game Control: -th Cost Cumulant Optimization
Abstract:
In this note, we study a Statistical Nash Game control problem where multiple players optimize system performance by shaping the distribution of their cost functions through cost cumulants. Our focus is on the nonzero-sum dynamic Statistical Nash Game, which generalizes the Risk-sensitive Nash game. The necessary and sufficient conditions for the Nash equilibrium solution are given for the N-player m-th cost cumulant optimization using the Hamilton-Jacobi-Bellman (HJB) equations. In addition, we derive the optimal control strategies and provide simulation results to demonstrate the performance of our method.
Autors: Chukwuemeka Aduba;Chang-Hee Won;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Sep 2016, volume: 61, issue:9, pages: 2688 - 2694
Publisher: IEEE
 
» -Terminal Reliability of -Trapezoid Graphs
Abstract:
Given a probabilistic graph, with reliable edges and unreliable vertices, K-terminal reliability problem is to find the probability that a given subset K of vertices remains connected. The problem is #P-complete for general graphs, even so for some special graphs such as chordal graphs, and comparability graphs. However, polynomial time algorithms to solve the problem have been designed for some special graphs such as interval graphs, permutation graphs, and d-trapezoid graphs. Existing time complexity of the polynomial time algorithm for the d-trapezoid graph is O(n2d+1), which is a very high degree polynomial. This makes it impractical to solve large problem instances using the existing algorithm. Here, we propose a novel technique and use it to design a simple linear-time algorithm to solve the problem on d-trapezoid graphs. As the complexity of our algorithm is linear, it is no more a difficulty to solve large problem instances in small amount of time.
Autors: Sudarshan Roy;Krishna Daripa;Alak Kumar Datta;
Appeared in: IEEE Transactions on Reliability
Publication date: Sep 2016, volume: 65, issue:3, pages: 1240 - 1247
Publisher: IEEE
 
» -Band High-Efficiency Metamaterial Microwave Sources
Abstract:
In this paper, we present an S-band compact metamaterial microwave source, which is based on a rectangular output coupler and a new all-metal metamaterial slow-wave structure that has been proposed previously. Due to the reversed Cherenkov radiation of the metamaterial, this metamaterial microwave source can be considered as a new sort of backward wave oscillators (BWOs). The S-band metamaterial microwave source has been further studied and analyzed by using Ansoft HFSS and CST Particle studio particle-in-cell solver. The simulated results show that the electronic efficiency of this S-band metamaterial microwave source can go up to 90% with the peak output power of 4.5 MW. When compared with conventional BWOs, it has obvious advantages such as miniaturization and high electronic efficiency.
Autors: Yanshuai Wang;Zhaoyun Duan;Fei Wang;Shifeng Li;Yan Nie;Yubin Gong;Jinjun Feng;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2016, volume: 63, issue:9, pages: 3747 - 3752
Publisher: IEEE
 
» Fault Detection for Networked Mechanical Spring-Mass Systems With Incomplete Information
Abstract:
This paper focuses on the H fault detection (FD) problem for spring-mass systems (SMSs) over networks with distributed state delays, random packet losses, sensor saturation as well as multiplicative noises via unreliable communication channels. The output measurements are affected by sensor saturation which is described by sector-nonlinearities. The multiplicative noises are described as a form of Gaussian white noises multiplied by the states. A series of stochastic variables are introduced to describe the randomly occurring distributed state delays. Random packet losses are also introduced in unreliable communications. The purpose of this paper is to design an FD filter such that: 1) The FD dynamic system is exponentially stable in the mean square. 2) The error between the fault signal and the residual signal is controlled to the minimum. 3) The optimal H filtering performance index is achieved. A sufficient condition for the FD filter design is derived in terms of the solution to a linear matrix inequality (LMI). When the LMI has a feasible solution, the explicit parameters of the desired FD filter can be obtained. Finally, a simulation experiment is illustrated to show the effectiveness and application of the designed method.
Autors: Huaicheng Yan;Fengfeng Qian;Hao Zhang;Fuwen Yang;Ge Guo;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2016, volume: 63, issue:9, pages: 5622 - 5631
Publisher: IEEE
 
» -Terminal Reliability of -Trapezoid Graphs
Abstract:
Given a probabilistic graph, with reliable edges and unreliable vertices, -terminal reliability problem is to find the probability that a given subset of vertices remains connected. The problem is #P-complete for general graphs, even so for some special graphs such as chordal graphs, and comparability graphs. However, polynomial time algorithms to solve the problem have been designed for some special graphs such as interval graphs, permutation graphs, and -trapezoid graphs. Existing time complexity of the polynomial time algorithm for the -trapezoid graph is , which is a very high degree polynomial. This makes it impractical to solve large problem instances using the existing algorithm. Here, we propose a novel technique and use it to design a simple linear-time algorithm to solve the problem on -trapezoid graphs. As the complexity of our algorithm is linear, it is no more a difficulty to solve large problem instances in small amount of time.
Autors: Sudarshan Roy;Krishna Daripa;Alak Kumar Datta;
Appeared in: IEEE Transactions on Reliability
Publication date: Sep 2016, volume: 65, issue:3, pages: 1240 - 1247
Publisher: IEEE
 
» -Player Statistical Nash Game Control: -th Cost Cumulant Optimization
Abstract:
In this note, we study a Statistical Nash Game control problem where multiple players optimize system performance by shaping the distribution of their cost functions through cost cumulants. Our focus is on the nonzero-sum dynamic Statistical Nash Game, which generalizes the Risk-sensitive Nash game. The necessary and sufficient conditions for the Nash equilibrium solution are given for the -player -th cost cumulant optimization using the Hamilton-Jacobi-Bellman (HJB) equations. In addition, we derive the optimal control strategies and provide simulation results to demonstrate the performance of our method.
Autors: Chukwuemeka Aduba;Chang-Hee Won;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Sep 2016, volume: 61, issue:9, pages: 2688 - 2694
Publisher: IEEE
 
» ESync: Energy Synchronized Mobile Charging in Rechargeable Wireless Sensor Networks
Abstract:
Recent years have witnessed many new promising technologies to power wireless sensor networks, which motivate some fundamental topics to be revisited. Different from energy harvesting, which generates dynamic energy supply, the mobile charger is able to provide a stable and reliable energy supply for sensor nodes and, thus, enables sustainable system operations. While previous mobile charging protocols focus on either the charger travel distance or the charging delay of sensor nodes, in this work, we propose a novel energy synchronized mobile charging (ESync) protocol, which simultaneously reduces both of them. Observing the limitation of traveling salesman problem (TSP)-based solutions, when the nodes' energy consumption is diverse, we construct a set of nested TSP tours based on their energy consumption, and only nodes with low remaining energy are involved in each charging round. Furthermore, we propose the concept of energy synchronization to synchronize the charging request sequence of nodes with their sequence on the TSP tours. Experimentation and simulation demonstrate that ESync can reduce charger travel distance and nodes' charging delay by about 30% and 40%, respectively.
Autors: Lingkun Fu;Liang He;Peng Cheng;Yu Gu;Jianping Pan;Jiming Chen;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Sep 2016, volume: 65, issue:9, pages: 7415 - 7431
Publisher: IEEE
 
» In Situ Composites of -CoxFe2–xO3 With -CoxFe2–xO3 or With Co–Fe Alloys Having Different Morphology and Better Magnetic Behavior
Abstract:
One-dimensional magnetic materials find several applications in modern technology. Co-Fe alloys and their oxides CoxFe2-xO3 (0 ≤ × ≤ 0.7) were prepared using a very simple and novel technique. The X-ray diffraction patterns confirm the coexistence α-Fe2O3 and ε-Fe2O3 phases in the as-prepared as well as the sample sintered in N2 atmosphere. In contrast, samples sintered in H2 atmosphere could provide Co-Fe alloys and α-Fe2O3 composites. Nanorod shapes for oxide samples were corroborated by scanning and transmission electron microscopy. A reasonably high coercivity value (~118 mT) was observed for such rods, whereas a sufficiently high saturation magnetization value near 162 Am2/kg was obtained for other types of composites.
Autors: Pankaj Goyal;Nand Kishore Prasad;
Appeared in: IEEE Transactions on Magnetics
Publication date: Sep 2016, volume: 52, issue:9, pages: 1 - 6
Publisher: IEEE
 
» In Vivo Characterization of Cortical Bone Using Guided Waves Measured by Axial Transmission
Abstract:
Cortical bone loss is not fully assessed by the current X-ray methods, and there is an unmet need in identifying women at risk of osteoporotic fracture, who should receive a treatment. The last decade has seen the emergence of the ultrasound (US) axial transmission (AT) techniques to assess a cortical bone. Recent AT techniques exploit the multimode waveguide response of the long bones such as the radius. A recent ex vivo study by our group evidenced that a multimode AT approach can yield simultaneous estimates of cortical thickness (Ct.Th) and stiffness. The aim of this paper is to move one step forward to evaluate the feasibility of measuring multimode guided waves (GW) in vivo and to infer from it cortical thickness. Measurements were taken on the forearm of 14 healthy subjects with the goal to test the accuracy of the estimated thickness using the bidirectional AT method implemented on a dedicated 1-MHz linear US array. This setup allows determining in vivo the dispersion curves of GW transmitted in the cortical layer of the radius. An inverse procedure based on the comparison between the measured and modeled dispersion curves predicted by a 2-D transverse isotropic free plate waveguide model allowed an estimation of cortical thickness, despite the presence of soft tissue. The Ct.Th values were validated by comparison with the site-matched estimates derived from X-ray high-resolution peripheral quantitative computed tomography. Results showed a significant correlation between both measurements (, , and mm). This pilot study demonstrates the potential of bidirectional AT for the in vivo assessment of cortical thickness, a bone strength-related factor.
Autors: Quentin Vallet;Nicolas Bochud;Christine Chappard;Pascal Laugier;Jean-Gabriel Minonzio;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Sep 2016, volume: 63, issue:9, pages: 1361 - 1371
Publisher: IEEE
 
» In Vivo Estimation of Attenuation and Backscatter Coefficients From Human Thyroids
Abstract:
Fine-needle aspiration (FNA) remains the gold standard for the diagnosis of thyroid cancer. However, currently, a large number of FNA biopsies result in negative or undetermined diagnosis, which suggests that better noninvasive tools are needed for the clinical management of thyroid cancer. Spectral-based quantitative ultrasound (QUS) characterizations may offer a better diagnostic management as previously demonstrated in mouse cancer models ex vivo. As a first step toward understanding the potential of QUS markers for thyroid disease management, this paper deals with the spectral-based QUS estimation of healthy human thyroids in vivo. Twenty volunteers were inspected by a trained radiologist using two ultrasonic imaging systems, which allowed them to acquire radio-frequency data spanning the 3–16-MHz frequency range. Estimates of attenuation coefficient slope (ACS) using the spectral logarithmic difference method had an average value of ) with a standard deviation of . Estimates of backscatter coefficient (BSC) using the reference-phantom method had an average value of over the useful frequency range. The intersubject variability when estimating BSCs was less than 1.5 dB over the analysis frequency range. Further, the effectiveness of three scattering models (i.e., fluid sphere, Gaussian, and exponential form factors) when fitting the experimentally estimated BSCs was assessed. The exponential form factor was found to provide the best overall goodness of fit (), followed by the Gaussian () and the fluid-sphere models (). For all scattering models used in this study, average estimates of the effective scatterer diameter were between 44 and . Overall, an excellent agreement in the estimated attenuation and BSCs with both scanners was exhibited.
Autors: Julien Rouyer;Tony Cueva;Tamy Yamamoto;Alberto Portal;Roberto J. Lavarello;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Sep 2016, volume: 63, issue:9, pages: 1253 - 1261
Publisher: IEEE
 
» In-Situ Requirements Monitoring of Embedded Systems
Abstract:
We present a requirements-driven methodology enabling efficient runtime monitoring of embedded systems. The proposed approach extracts a runtime monitoring graph from system requirements specified using unified modeling language sequence diagrams with timing annotations. Nonintrusive, in-situ, on-chip hardware dynamically monitors the system execution, matches the specified requirements, and provides detailed information that can be analyzed in the event of a system failure. We present a case study using an autonomous vehicle subsystem demonstrating that the approach can achieve 100% detection rate of common failure types, including timing, dependency, synchronization, and sensor failures. We further analyze the relationship between coverage of system events, detection rates, and hardware requirements.
Autors: Minjun Seo;Roman Lysecky;
Appeared in: IEEE Embedded Systems Letters
Publication date: Sep 2016, volume: 8, issue:3, pages: 49 - 52
Publisher: IEEE
 
» MaterialCloning: Acquiring Elasticity Parameters from Images for Medical Applications
Abstract:
We present a practical approach for automatically estimating the material properties of soft bodies from two sets of images, taken before and after deformation. We reconstruct 3D geometry from the given sets of multiple-view images; we use a coupled simulation-optimization-identification framework to deform one soft body at its original, non-deformed state to match the deformed geometry of the same object in its deformed state. For shape correspondence, we use a distance-based error metric to compare the estimated deformation fields against the actual deformation field from the reconstructed geometry. The optimal set of material parameters is thereby determined by minimizing the error metric function. This method can simultaneously recover the elasticity parameters of multiple types of soft bodies using Finite Element Method-based simulation (of either linear or nonlinear materials undergoing large deformation) and particle-swarm optimization methods. We demonstrate this approach on real-time interaction with virtual organs in patient-specific surgical simulation, using parameters acquired from low-resolution medical images. We also highlight the results on physics-based animation of virtual objects using sketches from an artist's conception.
Autors: Shan Yang;Ming C. Lin;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Sep 2016, volume: 22, issue:9, pages: 2122 - 2135
Publisher: IEEE
 
» A 0.25–3.25-GHz Wideband CMOS-RF Spectrum Sensor for Narrowband Energy Detection
Abstract:
A wideband spectrum sensing system for cognitive radio is designed and implemented in a 130-nm radio frequency mixed-mode CMOS technology. The system employs an downconverter, a pair of complex filters, and a pair of envelope detectors to perform the spectrum sensing from 250 MHz to 3.25 GHz. The design makes use of the bandpass nature of the complex filter to achieve two objectives: 1) separation of upper sideband and lower sideband around the local oscillator signal and 2) resolution of smaller bands within a large detection bandwidth. The measured sensitivity is close to −45 dBm for a single tone test over a bandwidth of 40 MHz. The measured image reject ratio is close to 30 dB. The overall wideband detection bandwidth is 250 MHz, which is partitioned into 40-MHz narrowband chunks with eight such overlapping chunks.
Autors: Vishal Khatri;Gaurab Banerjee;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Sep 2016, volume: 24, issue:9, pages: 2887 - 2898
Publisher: IEEE
 
» A 0.36 pJ/bit, 0.025 mm, 12.5 Gb/s Forwarded-Clock Receiver With a Stuck-Free Delay-Locked Loop and a Half-Bit Delay Line in 65-nm CMOS Technology
Abstract:
This paper describes a power and area-efficient forwarded-clock (FC) receiver and includes an analysis of the jitter tolerance of the FC receiver. In the proposed design, jitter tolerance is maximized according to the analysis by employing a delay-locked loop (DLL) based de-skewing. A sample-swapping bang-bang phase-detector (SS-BBPD) eliminates the stuck locking caused by the finite delay range of the voltage-controlled delay line (VCDL), and also reduces the required delay range of the VCDL by half. The proposed FC receiver is fabricated in 65-nm CMOS technology and occupies an active area of 0.025 mm2. At a data rate of 12.5 Gb/s, the proposed FC receiver exhibits an energy efficiency of 0.36 pJ/bit, and tolerates 1.4- sinusoidal jitter of 300 MHz.
Autors: Woorham Bae;Gyu-Seob Jeong;Kwanseo Park;Sung-Yong Cho;Yoonsoo Kim;Deog-Kyoon Jeong;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Sep 2016, volume: 63, issue:9, pages: 1393 - 1403
Publisher: IEEE
 
» A 0.45 V, Nano-Watt 0.033% Line Sensitivity MOSFET-Only Sub-Threshold Voltage Reference With no Amplifiers
Abstract:
An ultra-low voltage, low power, low line sensitivity MOSFET-only sub-threshold voltage reference with no amplifiers is presented. The low sensitivity is realized by the difference between two complementary currents and second-order compensation improves the temperature stability. The bulk-driven technique is used and most of the transistors work in the sub-threshold region, which allow a remarkable reduction in the minimum supply voltage and power consumption. Moreover, a trimming circuit is adopted to compensate the process-related reference voltage variation while the line sensitivity is not affected. The proposed voltage reference has been fabricated in the 0.18 1.8 V CMOS process. The measurement results show that the reference could operate on a 0.45 V supply voltage. For supply voltages ranging from 0.45 to 1.8 V the power consumption is 15.6 nW, and the average temperature coefficient is 59.4 ppm/°C across a temperature range of −40 to 85 °C and a mean line sensitivity of 0.033%. The power supply rejection ratio measured at 100 Hz is −50.3 dB. In addition, the chip area is 0.013 mm2.
Autors: Zhangming Zhu;Jin Hu;Yutao Wang;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Sep 2016, volume: 63, issue:9, pages: 1370 - 1380
Publisher: IEEE
 
» A 0.4W-to-21W Fast-Transient Global-Search-Algorithm Based Integrated Photovoltaic Energy Harvester With 99% GMPPT Efficiency and 94% Power Efficiency
Abstract:
This paper presents an integrated photovoltaic energy harvester that is capable of performing global maximum power point tracking (GMPPT) with significant reductions in MPPT transient time, power dissipation and silicon area. A fast-transient global search algorithm is proposed to identify the GMPP of a solar panel within hundreds of in the presence of multiple local maxima during partial shading conditions. The pulse integration based MPPT circuitry enables high-precision MPPT. Ripple-based irradiance aware adaptive frequency control (IAAFC) is also developed to lower the switching power loss under low irradiance levels, improving the harvester power efficiency over a wide output power range.
Autors: Sandip Uprety;Hoi Lee;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2016, volume: 51, issue:9, pages: 2153 - 2167
Publisher: IEEE
 
» A 10- Transient Recovery Time Low-EMI DC-DC Buck Converter With – Modulator
Abstract:
This paper presents a 10-μs transient recovery time and a low electromagnetic interference dc-dc buck converter with a second-order delta-sigma (Δ-Σ) modulator. The proposed buck converter employs the techniques of oversampling, noise shaping, fast-transient path, mode selector, and second-order Δ-Σ modulator to achieve spur reduction and to improve transient recovery time. As a result, the noise tones of the output voltage are less than the other conventional pulsewidth modulation converters. In addition, the fast-transient path could correct output voltage immediately, and the mode selector controls the duty cycle of the converter to limit overshoot voltage and undershoot voltage. The chip was implemented using a 0.35-μm Taiwan Semiconductor Manufacturing Company CMOS process. The measured results show that the transient recovery time is 10 μs from heavy load to light load and from light load to heavy load, and the noise power spectrum demonstrates a -64-dBm peak noise when the output voltage is 2 V and the output current is 300 mA. A maximum efficiency of 89% is measured at 3 V output voltage and at 3.6 V supply voltage.
Autors: Yuh-Shyan Hwang;Jiann-Jong Chen;Wei-Jhih Hou;Pao-Hua Liao;Yi-Tsen Ku;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Sep 2016, volume: 24, issue:9, pages: 2983 - 2992
Publisher: IEEE
 
» A 10- Transient Recovery Time Low-EMI DC-DC Buck Converter With – Modulator
Abstract:
This paper presents a 10- transient recovery time and a low electromagnetic interference dc–dc buck converter with a second-order delta–sigma (– modulator. The proposed buck converter employs the techniques of oversampling, noise shaping, fast-transient path, mode selector, and second-order – modulator to achieve spur reduction and to improve transient recovery time. As a result, the noise tones of the output voltage are less than the other conventional pulsewidth modulation converters. In addition, the fast-transient path could correct output voltage immediately, and the mode selector controls the duty cycle of the converter to limit overshoot voltage and undershoot voltage. The chip was implemented using a 0.35- Taiwan Semiconductor Manufacturing Company CMOS process. The measured results show that the transient recovery time is 10 from heavy load to light load and from light load to heavy load, and the noise power spectrum demonstrates a −64-dBm peak noise when the output voltage is 2 V and the output current is 300 mA. A maximum efficiency of 89% is measured at 3 V output voltage and at 3.6 V supply voltage.
Autors: Yuh-Shyan Hwang;Jiann-Jong Chen;Wei-Jhih Hou;Pao-Hua Liao;Yi-Tsen Ku;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Sep 2016, volume: 24, issue:9, pages: 2983 - 2992
Publisher: IEEE
 
» A 110 nW Resistive Frequency Locked On-Chip Oscillator with 34.3 ppm/°C Temperature Stability for System-on-Chip Designs
Abstract:
This work presents a sub- on-chip oscillator for fully integrated system-on-chip designs. The proposed oscillator introduces a resistive frequency locked loop topology for accurate clock generation. In this topology, a switched-capacitor circuit is controlled by an internal voltage-controlled oscillator (VCO), and the equivalent resistance of this switched-capacitor is matched to a temperature-compensated on-chip resistor using an ultra-low power amplifier. This design yields a temperature-compensated frequency from the internal VCO. The approach eliminates the traditional comparator from the oscillation loop; this comparator typically consumes a significant portion of the total oscillator power and limits temperature stability in conventional RC relaxation oscillators due to its temperature-dependent delay. A test chip is fabricated in CMOS that exhibits a temperature coefficient of 34.3 ppm/°C with long-term stability of less than 7 ppm (12 second integration time) while consuming 110 nW at 70.4 kHz. A radio transmitter circuit that uses the proposed oscillator as a baseband timing source is also presented to demonstrate a system-on-chip design using this oscillator.
Autors: Myungjoon Choi;Taekwang Jang;Suyoung Bang;Yao Shi;David Blaauw;Dennis Sylvester;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2016, volume: 51, issue:9, pages: 2106 - 2118
Publisher: IEEE
 
» A 14-bit 250 MS/s IF Sampling Pipelined ADC in 180 nm CMOS Process
Abstract:
This paper presents a 14-bit 250 MS/s ADC fabricated in a 180 nm CMOS process, which aims at optimizing its linearity, operating speed, and power efficiency. The implemented ADC employs an improved SHA with parasitic optimized bootstrapped switches to achieve high sampling linearity over a wide input frequency range. It also explores a dedicated foreground calibration to correct the capacitor mismatches and the gain error of residue amplifier, where a novel configuration scheme with little cost for analog front-end is developed. Moreover, a partial non-overlapping clock scheme associated with a high-speed reference buffer and fast comparators is proposed to maximize the residue settling time. The implemented ADC is measured under different input frequencies with a sampling rate of 250 MS/s and it consumes 300 mW from a 1.8 V supply. For 30 MHz input, the measured SFDR and SNDR of the ADC is 94.7 dB and 68.5 dB, which can remain over 84.3 dB and 65.4 dB for up to 400 MHz. The measured DNL and INL after calibration are optimized to 0.15 LSB and 1.00 LSB, respectively, while the Walden FOM at Nyquist frequency is 0.57 pJ/step.
Autors: Xuqiang Zheng;Zhijun Wang;Fule Li;Feng Zhao;Shigang Yue;Chun Zhang;Zhihua Wang;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Sep 2016, volume: 63, issue:9, pages: 1381 - 1392
Publisher: IEEE
 
» A 2.4 GHz Interferer-Resilient Wake-Up Receiver Using A Dual-IF Multi-Stage N-Path Architecture
Abstract:
A 2.4 GHz interferer-resilient wake-up receiver for ultra-low power wireless sensor nodes uses an uncertain-IF dual-conversion topology, combining a distributed multi-stage N-path filtering technique with an unlocked low-Q resonator-referred local oscillator. This structure provides narrow-band selectivity and strong immunity against interferers, while avoiding expensive external resonant components such as BAW resonators or crystals. The 65 nm CMOS receiver prototype provides a sensitivity of −97 dBm and a carrier-to-interferer ratio better than −27 dB at 5 MHz offset, for a data rate of 10 kb/s at a 10−3 bit error rate, while consuming 99 from a 0.5 V voltage supply under continuous operation.
Autors: Camilo Salazar;Andreia Cathelin;Andreas Kaiser;Jan Rabaey;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2016, volume: 51, issue:9, pages: 2091 - 2105
Publisher: IEEE
 
» A 200-MS/s Phase-Detector-Based Comparator With 400- Noise
Abstract:
A low-noise phase-detector-based comparator is proposed for SAR ADCs. It can reduce the thermal-induced noise as well as the probability of the metastability. The proposed comparator is composed of two front-end dynamic comparators and a backend phase detector. The comparator has been fabricated in a 0.18- CMOS technology and achieves 400- noise at a conversion rate of 200 MHz under a 1.8-V supply voltage while consuming 78 . Its active area is 0.001 mm2.
Autors: Chin-Yu Lin;Chien-Heng Wong;Chia-Hau Hsu;Yen-Hsin Wei;Tai-Cheng Lee;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Sep 2016, volume: 63, issue:9, pages: 813 - 817
Publisher: IEEE
 
» A 234–261-GHz 55-nm SiGe BiCMOS Signal Source with 5.4–7.2 dBm Output Power, 1.3% DC-to-RF Efficiency, and 1-GHz Divided-Down Output
Abstract:
A 234–261-GHz signal source with record 7.2-dBm output power at 240 GHz and −105 dBc/Hz phase noise at 10-MHz offset is reported. Fabricated in a production 55-nm SiGe BiCMOS process with HBT of 330/350 GHz, the circuit includes a 120-GHz fundamental frequency VCO with 1.2-V AMOS varactors, a broadband MOS-HBT cascode LO tree driving a divide-by-128 chain, and a doubler with a record drain efficiency of 11.9%. The total power consumption of the signal source is 386 mW resulting in a DC-to-RF efficiency of 1.3%. A detailed discussion of the candidate LO-tree and doubler topologies and of the design methodology, which capitalizes on the MOS-HBT cascode and unique features of the 55-nm SiGe BiCMOS process, is provided.
Autors: Stefan Shopov;Andreea Balteanu;Juergen Hasch;Pascal Chevalier;Andreia Cathelin;Sorin P. Voinigescu;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2016, volume: 51, issue:9, pages: 2054 - 2065
Publisher: IEEE
 
» A 25 Gb/s Hybrid-Integrated Silicon Photonic Source-Synchronous Receiver With Microring Wavelength Stabilization
Abstract:
Single-mode wavelength-division multiplexing (WDM) optical links are an attractive technology to meet the growing interconnect bandwidth demand in data center applications. This paper presents a multi-channel hybrid-integrated photonic receiver based on microring drop filters and waveguide photodetectors implemented in a 130 nm SOI process and high-speed optical front-ends designed in 65 nm CMOS. The source-synchronous receiver utilizes an LC injection-locked oscillator (ILO) in the clock path for improved jitter filtering, while maintaining correlated jitter tracking with the data channels. Receiver sensitivity is improved with a large input-stage feedback resistor transimpedance amplifier (TIA) cascaded with an adaptively-tuned continuous-time linear equalizer (CTLE). In order to stabilize the microring drop filter resonance wavelength, a peak-detector-based thermal tuning loop is implemented with a 0.7 nm range at /GHz efficiency. When tested with a waveguide photodetector with 0.45 A/W responsivity, the receiver achieves -8.0 dBm OMA sensitivity at a BER with a jitter tolerance corner frequency near 20 MHz and a per-channel power consumption of 17 mW including amortized clocking power.
Autors: Kunzhi Yu;Cheng Li;Hao Li;Alex Titriku;Ayman Shafik;Binhao Wang;Zhongkai Wang;Rui Bai;Chin-Hui Chen;Marco Fiorentino;Patrick Yin Chiang;Samuel Palermo;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2016, volume: 51, issue:9, pages: 2129 - 2141
Publisher: IEEE
 
» A 25. 3 W at 60 fps Pixel Vision Sensor for Motion Capturing With In-Pixel Nonvolatile Analog Memory Using CAAC-IGZO FET
Abstract:
Utilizing a c-axis-aligned crystalline oxide semiconductor-based FET, we have fabricated a vision sensor with in-pixel nonvolatile analog memory. The sensor realized normal image data capturing, captured differential data of a given reference frame, and retained the captured data for an extended time in each pixel. Moreover, the sensor realized normal global shutter image capturing and motion capturing by extracting differential images. This is performed using the captured data and depends on the presence or absence of differences between normal images and reference images. The sensor has three operating modes: an imaging mode, a motion capturing mode, and a wait mode. Importantly, power consumption is reduced by powering off circuit blocks that are in a standby state.
Autors: Takuro Ohmaru;Takashi Nakagawa;Shuhei Maeda;Yuki Okamoto;Munehiro Kozuma;Seiichi Yoneda;Hiroki Inoue;Yoshiyuki Kurokawa;Takayuki Ikeda;Yoshinori Ieda;Naoto Yamade;Hidekazu Miyairi;Makoto Ikeda;Shunpei Yamazaki;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2016, volume: 51, issue:9, pages: 2168 - 2179
Publisher: IEEE
 
» A 25. 3 W at 60 fps Pixel Vision Sensor for Motion Capturing With In-Pixel Nonvolatile Analog Memory Using CAAC-IGZO FET
Abstract:
Utilizing a c-axis-aligned crystalline oxide semiconductor-based FET, we have fabricated a vision sensor with in-pixel nonvolatile analog memory. The sensor realized normal image data capturing, captured differential data of a given reference frame, and retained the captured data for an extended time in each pixel. Moreover, the sensor realized normal global shutter image capturing and motion capturing by extracting differential images. This is performed using the captured data and depends on the presence or absence of differences between normal images and reference images. The sensor has three operating modes: an imaging mode, a motion capturing mode, and a wait mode. Importantly, power consumption is reduced by powering off circuit blocks that are in a standby state.
Autors: Takuro Ohmaru;Takashi Nakagawa;Shuhei Maeda;Yuki Okamoto;Munehiro Kozuma;Seiichi Yoneda;Hiroki Inoue;Yoshiyuki Kurokawa;Takayuki Ikeda;Yoshinori Ieda;Naoto Yamade;Hidekazu Miyairi;Makoto Ikeda;Shunpei Yamazaki;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2016, volume: 51, issue:9, pages: 2168 - 2179
Publisher: IEEE
 
» A 3-D ZnO-Nanowire Smart Photo Sensor Prepared With Through Silicon via Technology
Abstract:
The authors report the fabrication of a 3-D ZnO-nanowire/MOSFET smart photo sensor using through silicon via technology. It was found that the MOSFET, prepared by hot-wire chemical vapor deposition, exhibits standard saturation and pinch-off characteristics. The dynamic response of the 3-D ZnO-nanowire/MOSFET smart photo sensor was stable and reproducible with an ON–OFF current contrast ratio larger than one order of magnitude. As we turned OFF the ultraviolet illumination, it was found that the decay time was smaller than 1 s for the 3-D ZnO-nanowire/MOSFET smart photo sensor, which was significantly shorter than that observed from the conventional ZnO nanowire photo sensor.
Autors: Kin-Tak Lam;Yi-Hao Chen;Ting-Jen Hsueh;Shoou-Jinn Chang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2016, volume: 63, issue:9, pages: 3562 - 3566
Publisher: IEEE
 
» A 30–75 2.5 GHz 0.13- CMOS Receiver Front-End With Large Input Capacitance Tolerance for Short-Range Optical Communication
Abstract:
This paper describes the design and implementation of a linear optical receiver front-end for short range optical communication applications in 0.13- CMOS technology. While conventional optical receivers are typically implemented using limiting amplifiers (LA), emerging optical systems are expected to employ advanced modulation schemes, which require preserving the signal envelope. The proposed linear optical receiver architecture utilizes super-Gm transimpedance amplification with common-mode restoration and constant settling time automatic gain control (AGC) with background illumination cancellation to preserve the signal linearity while tolerating capacitance up to 15 pF for large area photo-detectors. Linearity aware design of transimpedance amplifiers (TIA), variable gain control (VGA), and post amplifiers (PA) are discussed before introducing an exponential generator based on the parasitic BJTs available in the used technology. Consuming 40 mW from a 1.2 V supply in the presence of ∼15 pF input capacitance, the circuit achieves a binary modulation data rate of 5 Gbps with an input sensitivity of maintaining a bit-error rate (BER) . S-parameter measurements show a constant −3 dB bandwidth of 2.5 GHz for a wide dynamic range of ∼45 dB (30–75 ) with dB-linearity error better than ±1 dB. To demonstrate the optical functionality of the architecture, an external photodiode (PDCS70T-GS) is directly wirebonded to the chip. Optical measurements confirm a sensitivity of −9.5 dBm at a highest data rate of 5 Gb/s . The noise and linearity performance of the receiver is verified using input referred integrated noise and 1 dB-compression point measurements for different gain settings.
Autors: Sagar Ray;Mona Mostafa Hella;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Sep 2016, volume: 63, issue:9, pages: 1404 - 1415
Publisher: IEEE
 
» A 5.6 nV/Hz Chopper Operational Amplifier Achieving a 0.5 V Maximum Offset Over Rail-to-Rail Input Range With Adaptive Clock Boosting Technique
Abstract:
This paper presents a standalone 5.6 nV/√Hz chopper op-amp that operates from a 2.1-5.5 V supply. Frequency compensation is achieved in a power-and area-efficient manner by using a current attenuator and a dummy differential output. As a result, the overall op-amp only consumes 1.4 mA supply current and 1.26 mm2 die area. Up-modulated chopper ripple is suppressed by a local feedback technique, called auto correction feedback (ACFB). The charge injection of the input chopping switches can cause residual offset voltages, especially with the wider switches needed to reduce thermal noise. By employing an adaptive clock boosting technique with NMOS input switches, the amount of charge injection is minimized and kept constant as the input common-mode voltage changes. This results in a 0.5 μV maximum offset and 0.015 μV/°C maximum drift over the amplifier's entire rail-to-rail input common-mode range and from -40 °C to 125 °C. The design is implemented in a 0.35 μm CMOS process augmented by 5 V CMOS transistors.
Autors: Yoshinori Kusuda;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2016, volume: 51, issue:9, pages: 2119 - 2128
Publisher: IEEE
 
» A 5.6 nV/Hz Chopper Operational Amplifier Achieving a 0.5 V Maximum Offset Over Rail-to-Rail Input Range With Adaptive Clock Boosting Technique
Abstract:
This paper presents a standalone 5.6 nV/Hz chopper op-amp that operates from a 2.1–5.5 V supply. Frequency compensation is achieved in a power- and area-efficient manner by using a current attenuator and a dummy differential output. As a result, the overall op-amp only consumes 1.4 mA supply current and 1.26 mm2 die area. Up-modulated chopper ripple is suppressed by a local feedback technique, called auto correction feedback (ACFB). The charge injection of the input chopping switches can cause residual offset voltages, especially with the wider switches needed to reduce thermal noise. By employing an adaptive clock boosting technique with NMOS input switches, the amount of charge injection is minimized and kept constant as the input common-mode voltage changes. This results in a maximum offset and /°C maximum drift over the amplifier’s entire rail-to-rail input common-mode range and from −40 °C to 125 °C. The design is implemented in a 0.35 CMOS process augmented by 5 V CMOS transistors.
Autors: Yoshinori Kusuda;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2016, volume: 51, issue:9, pages: 2119 - 2128
Publisher: IEEE
 
» A 5.8 GHz 54 Mb/s Backscatter Modulator for WLAN With Symbol Pre-Distortion and Transmit Pulse Shaping
Abstract:
This letter discusses the implementation of microwave backscatter links in CMOS technology which are similar to existing systems at mid-UHF for RFID, but intended for use at the 5.8 GHz ISM band for supporting future low-power WLAN applications. In order for backscatter links to operate in highly channelized environments we introduce a pulse-shaping technique to reduce out-of-band emissions as well as a symbol pre-distortion technique to improve the constellation spacing. Both techniques are introduced into a 65 nm prototype backscatter modulator chip and are shown to operate with QPSK modulation at 54 Mb/s (typical of WLAN standards). The backscatter modulator chip was shown to consume 1.61 mW of power.
Autors: Adrian Tang;Yanghyo Kim;Yinuo Xu;Mau-Chung Frank Chang;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Sep 2016, volume: 26, issue:9, pages: 729 - 731
Publisher: IEEE
 
» A 500 °C 8-b Digital-to-Analog Converter in Silicon Carbide Bipolar Technology
Abstract:
High-temperature integrated circuits provide important sensing and controlling functionality in extreme environments. Silicon carbide bipolar technology can operate beyond 500 °C and has shown stable operation in both digital and analog circuit applications. This paper demonstrates an 8-b digital-to-analog converter (DAC). The DAC is realized in a current steering R-2R configuration. High-gain Darlington current switches are used to ensure ideal switching at 500 °C. The measured differential nonlinearity (DNL) and integral nonlinearity (INL) at 25 °C are 0.79 and 1.01 LSB, respectively, while at 500 °C, the DNL and INL are 4.7 and 2.5 LSB, respectively. In addition, the DAC achieves 53.6 and 40.6 dBc of spurious free dynamic range at 25 °C and 500 °C, respectively.
Autors: Raheleh Hedayati;Luigia Lanni;Bengt Gunnar Malm;Ana Rusu;Carl-Mikael Zetterling;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2016, volume: 63, issue:9, pages: 3445 - 3450
Publisher: IEEE
 
» A 57–78 GHz Frequency Tripler MMIC in 65-nm CMOS
Abstract:
In this letter, we present a MMIC frequency tripler using 65-nm CMOS technology. The tripler consists of a buffer stage that overdrives tripler devices into non-linear region, maximizing the third harmonic generation. Adopting differential architecture and transformers impedance matching, the tripler needs no explicit passive filter to enhance harmonic rejections. The tripler shows peak conversion gain of 1.3 dB, saturated output power of −2 dBm with −5 dBm input power. The 3-dB bandwidth spans 57–78 GHz with 60 mW dc consumption.
Autors: You-Tang Lee;Yuan-Hung Hsiao;Huei Wang;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Sep 2016, volume: 26, issue:9, pages: 723 - 725
Publisher: IEEE
 
» A Block-Based Medium-Long Term Energy Transaction Method
Abstract:
This letter proposes a novel medium-long term energy transaction method, in which the energies are traded in block and their duration and shiftable ability can be distinguished and reflected. In the bilateral auction mechanism, the users are motivated to accommodate consuming modes by scheduling the shiftable loads. The case studies have shown that the method helps to promote the integration of renewable power and improve the social benefits.
Autors: Chao Du;Xifan Wang;Xiuli Wang;Chengcheng Shao;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2016, volume: 31, issue:5, pages: 4155 - 4156
Publisher: IEEE
 
» A Buck Power Factor Correction Converter with Predictive Quadratic Sinusoidal Current Modulation and Line Voltage Reconstruction
Abstract:
A buck power factor correction (PFC) converter operating in continuous conduction mode (CCM) is influenced by the dead zone, which introduces distortion related to the input line voltage. Such phenomenon limits the maximum power factor (PF) and the minimum total harmonic distortion (THD) achievable. By deriving a methodology to achieve predictive line voltage reconstruction (PLVR), the influence of the dead zone is mitigated. With the prediction of quadratic sinusoidal current modulation (PS2CM), the line current is shaped into sinusoid waveform that is in-phase with input line voltage, crucial for. Consequently, the proposed CCM buck PFC can achieve high PF, low THD, and efficiency simultaneously. A test chip was fabricated in 0.5-μm Bipolar-CMOS-DMOS (BCD) process. The experimental results show a peak PF of 0.95 and a peak efficiency of 98% at 110 Vac.
Autors: Shang-Hsien Yang;Che-Hao Meng;Chao-Chang Chiu;Chih-Wei Chang;Ke-Horng Chen;Ying-Hsi Lin;Shian-Ru Lin;Tsung-Yen Tsai;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2016, volume: 63, issue:9, pages: 5912 - 5920
Publisher: IEEE
 
» A Capacitor-Less LDO With High-Frequency PSR Suitable for a Wide Range of On-Chip Capacitive Loads
Abstract:
This paper presents an on-chip, low drop-out (LDO) voltage regulator with improved power-supply rejection (PSR) able to drive large capacitive loads. The LDO compensation is achieved via a custom, wide bandwidth capacitance multiplier (c-multiplier) that emulates a nanofarad-range capacitance at the LDO output node. The LDO frequency response resembles that of externally compensated LDOs, leading to a wide PSR frequency range without using an off-chip capacitor. To drive large capacitive loads without stability concerns, the supply-line capacitance of the load circuit is incorporated to the design of the LDO compensation scheme. The power-stability-performance tradeoffs involved in the design are discussed in detail. The LDO and the c-multiplier are implemented in 0.18- CMOS technology and target applications with load currents in the 10-mA range. Experimental results show that the LDO achieves a PSR better than −39 dB up to 20 MHz at 1.2 V output voltage, while maintaining a 97.4% current efficiency.
Autors: Jorge Zarate-Roldan;Mengde Wang;Joselyn Torres;Edgar Sánchez-Sinencio;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Sep 2016, volume: 24, issue:9, pages: 2970 - 2982
Publisher: IEEE
 
» A Cement Plant's Experience in Investigating Power Sags Leads to a Reduction in Kiln Outages by Utilizing Power Hardening Methods
Abstract:
Poor power quality can be a cause of several process interruptions, including kiln outages at a cement plant. The purpose of this report is to educate the reader on voltage sags, which are the most common power quality issue faced by an industrial plant. Industrial end-users should understand why they should be concerned about voltage sags at their facility and how the severity of a voltage sag can be quantified then related to the sensitivity of the installed plant equipment. This in turn can result in applying power hardening methods to process equipment that will benefit the facility by reducing the number of power quality-related process outages.
Autors: Alan C. Finch;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Sep 2016, volume: 52, issue:5, pages: 4435 - 4441
Publisher: IEEE
 
» A Chaotic System With Equilibria Located on the Rounded Square Loop and Its Circuit Implementation
Abstract:
A new 3-D chaotic system with infinitely many equilibria is proposed in this brief. It is exciting that these equilibrium points are located on a rounded square loop. Dynamical properties and the circuit implementation of the system are studied and reported.
Autors: Viet-Thanh Pham;Sajad Jafari;Christos Volos;Aggelos Giakoumis;Sundarapandian Vaidyanathan;Tomasz Kapitaniak;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Sep 2016, volume: 63, issue:9, pages: 878 - 882
Publisher: IEEE
 
» A Column Generation Method for Constructing and Scheduling Multiple Forwarding Trees in Wireless Sensor Networks
Abstract:
This paper considers the problem of jointly constructing and scheduling forwarding trees in a wireless sensor network, each to collect measurements from a group of sensor nodes at a single sink node. The goal is to construct such trees that gather measurements in the most energy efficient manner and with minimal gathering latency. We assume transmissions (carrying measurements) on wireless links interfere with one another, and thus, appropriate link scheduling is required to manage interference. We refer to this problem as forwarding tree construction and scheduling (FTCS). Each tree may be constructed independently, and then, its links are scheduled. However, when all trees are combined together, the shortest and energy efficient schedule may not be guaranteed. Furthermore, a large number of possible forwarding trees for each group of sensors may be considered. Both problems of enumerating forwarding trees and scheduling links for those trees are hard combinatorial problems. This is compounded by the fact that the two problems must be solved jointly, to guarantee the selection of the best forwarding trees that, when their links are scheduled, guarantee a shortest energy efficient schedule. After highlighting the complexity of the FTCS problem, we present a novel primal-dual decomposition method using column generation. We also highlight several challenges we faced when solving the decomposed problem and present efficient techniques for mitigating those challenges. One major advantage of this paper is that it can serve as a benchmark for evaluating the performance of any low complexity method for solving the FTCS problem for larger network instances, where no known exact solutions can be found.
Autors: Dariush Ebrahimi;Samir Sebbah;Chadi Assi;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Sep 2016, volume: 15, issue:9, pages: 6513 - 6523
Publisher: IEEE
 
» A Compact and Low-Profile Loop Antenna With Six Resonant Modes for LTE Smartphone
Abstract:
In this paper, a novel six-mode loop antenna covering 660–1100, 1710–3020, 3370–3900, and 5150–5850 MHz has been proposed for the application of long-term evolution (LTE) including the coming LTE in unlicensed spectrum and LTE-Licensed Assisted Access. Loop antennas offer better user experience than conventional planar inverted-F antennas (PIFAs), inverted-F antennas (IFAs), and monopole antennas because of their unique balanced modes (, ). However, the bandwidth of loop antennas is usually narrower than that of PIFA/IFA and monopole antennas due to these balanced modes. To overcome this problem, a novel monopole/dipole parasitic element, which operates at an unbalanced monopole-like mode and a balanced dipole-like mode, is first proposed for loop antennas to cover more frequency bands. Benefiting from the balanced mode, the proposed parasitic element is promising to provide better user experience than conventional parasitic elements. To the best of the authors’ knowledge, the balanced mode for a parasitic element is reported for the first time. The proposed antenna is able to provide excellent user experience while solving the problem of limited bandwidth in loop antennas. To validate the concept, one prototype antenna with a size of mm3 is designed, fabricated, and measured. Both simulations and experimental results are presented and discussed. Good performance is achieved.
Autors: Hang Xu;Hanyang Wang;Steven Gao;Hai Zhou;Yi Huang;Qian Xu;Yujian Cheng;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2016, volume: 64, issue:9, pages: 3743 - 3751
Publisher: IEEE
 
» A Compact One-Pin Mode Transition Circuit for Clock Synchronization in Current-Mode- Controlled Switching Regulators
Abstract:
This paper describes a one-pin mode transition circuit that addresses the issues related to clock synchronization in switching regulators during the mode transitions between external timing resistor and external clock. The proposed circuit reduces the circuit complexity needed to achieve mode transition during synchronization by utilizing switched-capacitor and sampling design techniques. It linearly converts the input clock frequency to a current to maintain constant amount of slope compensation for current-mode switching regulators across their switching frequency range of operation. This circuit is designed to operate from 100 KHz to 2.5 MHz and fabricated in a 0.35- BiCMOS–DMOS process. The total solution occupies 0.082 mm2 die area. Experimental results are presented from peak-current-mode buck regulators with one-pin synchronization circuit to show the performance improvement of using the proposed design approach over a phase-locked-loop-based design.
Autors: Erhan Ozalevli;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Sep 2016, volume: 24, issue:9, pages: 2960 - 2969
Publisher: IEEE
 
» A Compact SPICE Model for Organic TFTs and Applications to Logic Circuit Design
Abstract:
This work introduces a compact DC model developed for organic thin film transistors (OTFTs) and its SPICE implementation. The model relies on a modified version of the gradual channel approximation that takes into account the contact effects, occurring at nonohmic metal/organic semiconductor junctions, modeling them as reverse biased Schottky diodes. The model also comprises channel length modulation and scalability of drain current with respect to channel length. To show the suitability of the model, we used it to design an inverter and a ring oscillator circuit. Furthermore, an experimental validation of the OTFTs has been done at the level of the single device as well as with a discrete-component setup based on two OTFTs connected into an inverter configuration. The experimental tests were based on OTFTs that use small molecules in binder matrix as an active layer. The experimental data on the fabricated devices have been found in good agreement with SPICE simulation results, paving the way to the use of the model and the device for the design of OTFT-based integrated circuits.
Autors: Antonio Valletta;Ahmet S. Demirkol;Giovanni Maira;Mattia Frasca;Vincenzo Vinciguerra;Luigi G. Occhipinti;Luigi Fortuna;Luigi Mariucci;Guglielmo Fortunato;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Sep 2016, volume: 15, issue:5, pages: 754 - 761
Publisher: IEEE
 
» A Comparison of Acoustic Radiation Force-Derived Indices of Cardiac Function in the Langendorff Perfused Rabbit Heart
Abstract:
In the past decade, there has been an increased interest in characterizing cardiac tissue mechanics utilizing newly developed ultrasound-based elastography techniques. These methods excite the tissue mechanically and track the response. Two frequently used methods, acoustic radiation force impulse (ARFI) and shear-wave elasticity imaging (SWEI), have been considered qualitative and quantitative techniques providing relative and absolute measures of tissue stiffness, respectively. Depending on imaging conditions, it is desirable to identify indices of cardiac function that could be measured by ARFI and SWEI and to characterize the relationship between the measures. In this study, we have compared two indices (i.e., relaxation time constant used for diastolic dysfunction assessment and systolic/diastolic stiffness ratio) measured nearly simultaneously by M-mode ARFI and SWEI techniques. We additionally correlated ARFI-measured inverse displacements with SWEI-measured values of the shear modulus of stiffness. For the eight animals studied, the average relaxation time constant () measured by ARFI and SWEI were () and (), respectively (). Average systolic/diastolic stiffness ratios for ARFI and SWEI measurements were and , respectively ( (). In conclusion, the relaxation time constant and the systolic/diastolic stiffness ratio were calculated with good agreement between the ARFI- and SWEI-derived measurements. ARFI relative and SWEI absolute stiffness measurements were linearly related with varying slopes based on imaging conditions and subject tissue properties.
Autors: Maryam Vejdani-Jahromi;Mathew Nagle;Yang Jiang;Gregg E. Trahey;Patrick D. Wolf;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Sep 2016, volume: 63, issue:9, pages: 1288 - 1295
Publisher: IEEE
 
» A Compensation-Based Conic OPF for Weakly Meshed Networks
Abstract:
This letter presents a method for solving the optimal power flow (OPF) problem in weakly meshed networks, using complex power compensation and the branch flow conic formulation. The method extends the practical applicability of the branch flow conic OPF and has been successfully tested on distribution networks with up to 3145 nodes.
Autors: Rabih A. Jabr;Izudin Džafić;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2016, volume: 31, issue:5, pages: 4167 - 4168
Publisher: IEEE
 
» A Comprehensive Method for Reachability Analysis of Uncertain Nonlinear Hybrid Systems
Abstract:
Reachability analysis of nonlinear uncertain hybrid systems, i.e., continuous-discrete dynamical systems whose continuous dynamics, guard sets and reset functions are defined by nonlinear functions, can be decomposed in three algorithmic steps: computing the reachable set when the system is in a given operation mode, computing the discrete transitions, i.e., detecting and localizing when (and where) the continuous flowpipe intersects the guard sets, and aggregating the multiple trajectories that result from an uncertain transition once the whole flow-pipe has transitioned so that the algorithm can resume. This paper proposes a comprehensive method that provides a nicely integrated solution to the hybrid reachability problem. At the core of the method is the concept of MSPB, i.e., geometrical object obtained as the Minkowski sum of a parallelotope and an axes aligned box. MSPB are a way to control the over-approximation of the Taylor's interval integration method. As they happen to be a specific type of zonotope, they articulate perfectly with the zonotope bounding method that we propose to enclose in an optimal way the set of flowpipe trajectories generated by the transition process. The method is evaluated both theoretically by analyzing its complexity and empirically by applying it to well-chosen hybrid nonlinear examples.
Autors: Moussa Maïga;Nacim Ramdani;Louise Travé-Massuyès;Christophe Combastel;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Sep 2016, volume: 61, issue:9, pages: 2341 - 2356
Publisher: IEEE
 
» A Comprehensive Study of the Past, Present, and Future of Data Deduplication
Abstract:
Data deduplication, an efficient approach to data reduction, has gained increasing attention and popularity in large-scale storage systems due to the explosive growth of digital data. It eliminates redundant data at the file or subfile level and identifies duplicate content by its cryptographically secure hash signature (i.e., collision-resistant fingerprint), which is shown to be much more computationally efficient than the traditional compression approaches in large-scale storage systems. In this paper, we first review the background and key features of data deduplication, then summarize and classify the state-of-the-art research in data deduplication according to the key workflow of the data deduplication process. The summary and taxonomy of the state of the art on deduplication help identify and understand the most important design considerations for data deduplication systems. In addition, we discuss the main applications and industry trend of data deduplication, and provide a list of the publicly available sources for deduplication research and studies. Finally, we outline the open problems and future research directions facing deduplication-based storage systems.
Autors: Wen Xia;Hong Jiang;Dan Feng;Fred Douglis;Philip Shilane;Yu Hua;Min Fu;Yucheng Zhang;Yukun Zhou;
Appeared in: Proceedings of the IEEE
Publication date: Sep 2016, volume: 104, issue:9, pages: 1681 - 1710
Publisher: IEEE
 
» A Computer-Aided Data Acquisition System for Multichannel Seismic Monitoring and Recording
Abstract:
This paper presents an innovative approach based on hardware and software to develop a multichannel seismic monitoring and data acquisition embedded system. The hardware was designed by using basic electronic components and integrated circuits. It consists of two parts, signal processing and microcontroller circuits. The signal processing circuit is a combination of preamplifier, low-pass filter, gain control, high-pass filter, dc offset, and clipper circuits. The proposed data acquisition system is able to record data at a sampling rate of 300 , with 10-bit resolution. It has three modes: real-time monitoring, continuous recording, and seismic refraction. The detected seismic signals were filtered using analog filters, which are low pass with 1 kHz and high pass with 2 Hz. A universal serial bus was utilized to communicate between the hardware and the personal computer. A graphical user interface based on windows operating system was developed using Microsoft.NET Framework for transferring, processing, and analyzing the data. The system was tested and experimental results showing the performance of the proposed system were presented. Earth scientists can use this system for educational seismic experiments. It can be easily modified and used for other engineering applications.
Autors: Ozkan Kafadar;Ibrahim Sertcelik;
Appeared in: IEEE Sensors Journal
Publication date: Sep 2016, volume: 16, issue:18, pages: 6866 - 6873
Publisher: IEEE
 
» A Cyclic Scanning Repeater for Enhancing the Remote Distance of LC Passive Wireless Sensors
Abstract:
Inductor-capacitor (LC) passive wireless sensors have been used in situations where wired connections are impossible. When this scheme is applied to implanted or sealed fields, the sensors are required to be scaled down to small dimensions, which results in the limited remote distance. Here we present an approach to enhance the remote readout distance of the LC sensors by a cyclic-scanning repeater. The resonant frequency of the repeater is cyclic-scanned so as to detect that of the LC sensor, and the readout distance is enhanced by strong magnetic coupling. The proposed full-spectrum-enhancing approach has the simplified circuits when compared with other readout enhancement ways. An LC humidity sensor, as an example, is then monitored both with and without the proposed repeater. We have demonstrated that the readout distance with the cyclic-scanning repeater can achieve 3 times long as that without a repeater, while keeping the same for their signal intensity and sensitivity. Overall, this approach with the cyclic-scanning repeater enables a longer detection range and broader applications in the implanted or sealed fields.
Autors: Lei Dong;Li-Feng Wang;Cong Zhang;Qing-An Huang;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Sep 2016, volume: 63, issue:9, pages: 1426 - 1433
Publisher: IEEE
 
» A D-Band Frequency Sixtupler MMIC With Very Low DC Power Consumption
Abstract:
A novel frequency sixtupler is proposed and verified experimentally. It consists of an even-order harmonics generating stage and a mixing stage to convert the 2nd and the 4th harmonics into the 6th harmonic. Transistors in those two stages operate in class-C condition, thus, the sixtupler consumes very low DC power. A proof-of-concept circuit is designed and manufactured in a 0.25 InP DHBT Technology. The sixtupler delivers a maximum output power of −3.5 dBm at 121 GHz at an input power of 7 dBm. Its 3-dB bandwidth of the output power is 25 GHz in the frequency range from 100 GHz to 125 GHz. It demonstrates also more than 10 dBc rejection ratio of the unwanted harmonics in the frequency range from 110 to 125 GHz. The sixtupler consumes a DC power of only 20 mW, which to the authors knowledge, is the lowest among sixtuplers published so far. The sixtupler also achieves a state-of-the-art peak power efficiency of 1.9%.
Autors: Mingquan Bao;Rumen Kozhuharov;Herbert Zirath;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Sep 2016, volume: 26, issue:9, pages: 726 - 728
Publisher: IEEE
 
» A DC Capacitor Voltage Control Method for Active Power Filters Using Modified Reference Including the Theoretically Derived Voltage Ripple
Abstract:
This paper proposes a new dc capacitor voltage control method suitable for active power filters equipped with a small dc capacitor. The proposed control method calculates the theoretical dc capacitor voltage ripple and provides it to the dc capacitor voltage feedback controller as the reference. As a result, the proposed method has the capability to regulate the mean value of the dc capacitor voltage under a large voltage ripple condition. The proposed method also allows us to use a high feedback gain for suppressing the capacitor voltage fluctuations without any performance deterioration in the harmonic compensation. Experimental results confirm a good harmonic compensation and an effective voltage regulation performance under a small dc capacitor condition. The results also demonstrate a significant improvement in the capacitor voltage regulation even when a sudden load change occurs.
Autors: Tomoyuki Mannen;Hideaki Fujita;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Sep 2016, volume: 52, issue:5, pages: 4179 - 4187
Publisher: IEEE
 
» A Debate and Decision-Making Tool for Enhanced Learning
Abstract:
Debates have been used to develop critical thinking within teaching environments. Many learning activities are configured as working groups, which use debates to make decisions. Nevertheless, in a classroom debate, only a few students can participate; large work groups are similarly limited. Whilst the use of web tools would appear to offer a convenient solution, none of those currently available provides an automated system for organizing contributions into a logical structure, or for making decisions. To address this problem, this paper describes a new tool for managing and structuring debates over the Internet, and presents the results of a series of trials in an educational context. The tool enables users to post opinions and proposals, and to make multiple group decisions. The main advantages are that it does not require a moderator, and all contributions are automatically arranged into an intuitive structure. Thus, it enabled large groups to carry out bigger projects. Empirical results showed that it also encouraged the involvement of all the students in debates and allowed the participation of each student to be evaluated. The tool demonstrated its advantages over traditional oral debates and, as far as we are aware, it incorporates features not found in any other comparable web tool.
Autors: Diego A. López García;Tomás de J. Mateo Sanguino;Estefanía Cortés Ancos;Iñaki Fernández de Viana González;
Appeared in: IEEE Transactions on Learning Technologies
Publication date: Sep 2016, volume: 9, issue:3, pages: 205 - 216
Publisher: IEEE
 
» A Delayed Container Organization Approach to Improve Restore Speed for Deduplication Systems
Abstract:
Data deduplication has become necessary to improve the space-efficiency of large-scale distributed storage systems, as the global data have accumulated at an exponential rate and they have significant redundancy. However, the negative impact on restore performance is a main challenge for deduplication systems. One of the key reasons is that when restoring data, the low average useful data ratio (UDR) of containers wastes a considerable part of disk bandwidth to read useless data. This is mainly attributed to the uncontrollable compositions of containers. To solve this problem, we propose a new approach called Delayed Container Organization (DCO) to delay the construction of containers after accumulating some redundant data chunks in fast Non-Volatile Memory (NVM) devices to organize high-UDR containers. For example, data chunks in the intersection of some data segments can be organized together in one container to achieve both high deduplication ratio and high UDRs when restoring these related data segments. DCO is implemented in a prototype deduplication system. The experimental results indicate that compared with Capping, DCO promotes the average UDR of containers by 38.30 percent, improves the restore performance by a factor of 2.2, and achieves better space-efficiency and higher cost performance.
Autors: Jian Liu;Yunpeng Chai;Chang Yan;Xin Wang;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Sep 2016, volume: 27, issue:9, pages: 2477 - 2491
Publisher: IEEE
 
» A Differential QAM Detection in Uplink Massive MIMO Systems
Abstract:
In this paper, we address differential non-coherence detections in uplink massive multiple input multiple output (MIMO) systems. Utilizing the channel statistics information, a special 16 quadrature amplitude modulation (QAM) can be adopted to achieve differential detection in uplink massive MIMO systems, which avoids costs of pilots or channel estimation. In addition, a higher-order extension of this differential 16-QAM is also presented in this paper. Moreover, it is found that users in different cells can transmit symbols simultaneously without causing interference to each other by jointly processing signals from all base stations if the number of receive antennas goes to infinity. For comparison, we also provide the performances of the differential amplitude phase shift keying (DAPSK) and coherence detection with pilot contamination in uplink massive MIMO systems, respectively. Simulation results show that the proposed differential 16-QAM scheme exhibits significant advantage over 16-DAPSK, and exhibits a large performance gain compared with the coherence detection with pilot contamination.
Autors: Dejin Kong;Xiang-Gen Xia;Tao Jiang;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Sep 2016, volume: 15, issue:9, pages: 6371 - 6383
Publisher: IEEE
 
» A Digital Predictive Current-Mode Controller for a Single-Phase High-Frequency Transformer-Isolated Dual-Active Bridge DC-to-DC Converter
Abstract:
This paper presents predictive current-mode control for a single-phase high-frequency transformer-isolated dual-active bridge dc-to-dc converter. The predictive control algorithm increases the bandwidth of the current loop of the converter which enables tracking of the current reference within one switching cycle. The paper further demonstrates that the application of the predictive control algorithm can remove transient dc offset from the current in high-frequency isolation transformer within one switching cycle. Direct control of the converter current protects the transformer from saturation even at transient conditions. The control algorithm has been implemented on an experimental setup and transient tests have been performed to validate controller performance. Since the predictive control algorithm is dependent on the measured value of the leakage inductance of the transformer, a compensator has been implemented to improve the parameter insensitivity of the proposed controller.
Autors: Sumit Dutta;Samir Hazra;Subhashish Bhattacharya;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2016, volume: 63, issue:9, pages: 5943 - 5952
Publisher: IEEE
 
» A Distributed Algorithm for Convex Constrained Optimization Under Noise
Abstract:
We present a novel distributed algorithm for convex constrained optimization problems that are subject to noise corruption and uncertainties. The proposed scheme can be classified as a distributed stochastic approximation method, where a unique feature here is that we allow for multiple noise terms to appear in both the computation and communication stages of the distributed iterative process. Specifically, we consider problems that involve multiple agents optimizing a separable convex objective function subject to convex local constraints and linear coupling constraints. This is a richer class of problems compared to those that can be handled by existing distributed stochastic approximation methods which consider only consensus constraints and fewer sources of noise. The proposed algorithm utilizes the augmented Lagrangian (AL) framework, which has been widely used recently to solve deterministic optimization problems in a distributed way. We show that the proposed method generates sequences of primal and dual variables that converge to their respective optimal sets almost surely.
Autors: Nikolaos Chatzipanagiotis;Michael M. Zavlanos;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Sep 2016, volume: 61, issue:9, pages: 2496 - 2511
Publisher: IEEE
 
» A Distributed Algorithm to Achieve Transparent Coexistence for a Secondary Multi-Hop MIMO Network
Abstract:
The transparent coexistence (TC) paradigm allows simultaneous activation of the secondary users with the primary users as long as their interference to the primary users can be properly canceled. This paradigm has the potential to offer much more efficient spectrum sharing than the traditional interweave paradigm. In this paper, we design a distributed algorithm to achieve this paradigm for a secondary multi-hop network. For interference cancelation (IC), we employ MIMO at secondary nodes. We present a distributed iterative algorithm to maximize each secondary session’s throughput while meeting all IC requirements under TC. By maintaining two local sets for each node, we can keep track of the node’s IC responsibility. Although no explicit node ordering is maintained in our distributed algorithm, we prove that our distributed data structure at each node (with the use of two local sets) can be mapped to an explicit global node ordering for IC among all nodes in the network. This guarantees that each active node’s degree-of-freedoms allocated for IC is feasible at the physical layer. Our algorithm is iterative in nature and all steps can be accomplished based on local information exchange among the neighboring nodes. We present the simulation results to show that the performance of our distributed algorithm is highly competitive when compared with an upper bound solution from the corresponding centralized problem.
Autors: Xu Yuan;Xiaoqi Qin;Feng Tian;Yi Shi;Y. Thomas Hou;Wenjing Lou;Scott F. Midkiff;Sastry Kompella;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Sep 2016, volume: 15, issue:9, pages: 6063 - 6077
Publisher: IEEE
 
» A Distributed Calculation of Global Shift Factor Considering Information Privacy
Abstract:
As an important sensitivity study, the global shift factor calculation of the interconnected power systems is facing challenges due to the distributed management structure of the system and the information privacy between systems. This letter proposes a distributed calculation platform to obtain a global shift factor while protecting information privacy of individuals.
Autors: Chunheng Wang;Yong Fu;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2016, volume: 31, issue:5, pages: 4161 - 4162
Publisher: IEEE
 
» A Distributed Feedforward Approach to Cooperative Control of AC Microgrids
Abstract:
This paper addresses the cooperative control problem of AC microgrids consisting of both voltage-controlled voltage-source inverters and current-controlled voltage-source inverters. The voltage-controlled voltage-source inverters dictate the frequency and voltage of the microgrid and the current-controlled voltage-source inverters provide quick and decoupled active and reactive power support to the microgrid. To handle the nonlinear and heterogeneous dynamics of the inverters, we have developed a distributed feedforward approach based on the cooperative control of multi-agent systems. The proposed controller presents three advantages in comparison with the existing works. First, all the inverters share one communication network, and the locations of the inverters over the communication network can be arbitrarily sited as long as all the inverters are connected. Second, the selection of the control gains does not rely on either the whole microgrid dynamics or the topology of the communication network. Third, the inverters’ dynamics after input-output feedback linearization are allowed to be different. The effectiveness of the proposed controller is verified by the simulation study of a microgrid system for three cases, i.e., frequency and voltage restoration after islanding, active and reactive power adjustment after abrupt load changes and system performance subject to communication link failure and restoration.
Autors: He Cai;Guoqiang Hu;Frank L. Lewis;Ali Davoudi;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2016, volume: 31, issue:5, pages: 4057 - 4067
Publisher: IEEE
 
» A Distributed Gauss-Newton MethodPub _newline for Power System State Estimation
Abstract:
We propose a fully distributed Gauss-Newton algorithm for state estimation of electric power systems. At each Gauss-Newton iteration, matrix-splitting techniques are utilized to carry out the matrix inversion needed for calculating the Gauss-Newton step in a distributed fashion. In order to reduce the communication burden as well as increase robustness of state estimation, the proposed distributed scheme relies only on local information and a limited amount of information from neighboring areas. The matrix-splitting scheme is designed to calculate the Gauss-Newton step with exponential convergence speed. The effectiveness of the method is demonstrated in various numerical experiments.
Autors: Ariana Minot;Yue M. Lu;Na Li;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2016, volume: 31, issue:5, pages: 3804 - 3815
Publisher: IEEE
 
» A Distributed Model Predictive Control Strategy for Back-to-Back Converters
Abstract:
In recent years, model predictive control (MPC) has been successfully used for the control of power electronics converters with different topologies and for different applications. MPC offers many advantages over more traditional control techniques such as the ability to avoid cascaded control loops, easy inclusion of constraint, and fast transient response. On the other hand, the controller computational burden increases exponentially with the system complexity and may result in an unfeasible realization on modern digital control boards. This paper proposes a novel distributed MPC (DMPC), which is able to achieve the same performance of the classical MPC while reducing the computational requirements of its implementation. The proposed control approach is tested on a ac/ac converter in a back-to-back configuration used for power flow management. Simulation results are provided and validated through experimental testing in several operating conditions.
Autors: Luca Tarisciotti;Giovanni Lo Calzo;Alberto Gaeta;Pericle Zanchetta;Felipe Valencia;Doris Sáez;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2016, volume: 63, issue:9, pages: 5867 - 5878
Publisher: IEEE
 
» A Diversity Model Based on Failure Distribution and its Application in Safety Cases
Abstract:
This work develops a new basis for evaluating the reliability benefits of diverse software, based on fault injection testing. In particular, the work investigates new forms of argumentation that could in principle be used to justify diversity as a basis for the construction of safety claims. Failure distributions of two versions of diverse software under various fault conditions are revealed separately by fault injection methods, and then the common failure probability of the version-pair can be estimated. The approach is justified theoretically, and cross validated with other work. This method is also used to explain the fundamental influence of failure distributions on diversity. Furthermore, the unique capabilities of the method are demonstrated by implementation of the fault injection test on a program pair
Autors: Luping Chen;John H. R. May;
Appeared in: IEEE Transactions on Reliability
Publication date: Sep 2016, volume: 65, issue:3, pages: 1149 - 1162
Publisher: IEEE
 
» A Diversity-Multiplexing Tradeoff Optimal Low Complexity Zero Forcing Method Based on ZP-OFDM
Abstract:
Due to the computational complexity of maximum-likelihood signal decoding, the equalizers with less complexity are considered in the literature. Employing the zero forcing (ZF) equalizer, zero-padded orthogonal frequency-division multiplexing (ZP-OFDM) is capable of benefiting the maximum available multipath diversity with the computational complexity of inverting a matrix of the size of data block length, which incurs an extra implementation cost relative to the fast Fourier transform-based OFDM decoder. In this paper, based on the ZP-OFDM encoding scheme, we propose a two-stage decoder that attains the maximum multipath diversity with lower computational complexity, as compared with the ZF ZP-OFDM and prove analytically that our proposed decoder is diversity-multiplexing tradeoff optimal. It has also been shown that by setting the decoder parameters, it can attain any arbitrary diversity gain smaller than the maximum multipath diversity. Moreover, the more the diversity gain is decreased the more the computational complexity is reduced.
Autors: Mehrdad Niroomand;Mostafa Derakhtian;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Sep 2016, volume: 15, issue:9, pages: 6412 - 6422
Publisher: IEEE
 
» A Dual-Hop Virtual MIMO Architecture Based on Hybrid Differential Spatial Modulation
Abstract:
In this paper, we propose a novel virtual multi-input-multi-output (VMIMO) architecture to convey information from the source node (SN) to the destination node (DN) via multiple relay nodes (RNs). As it is built on dual-hop networks with differential spatial modulation (DSM), we call it dual-hop hybrid DSM (DH-HDSM). In order to harvest the diversity provided by the SN and reduce the complexity at the RNs, DH-HDSM forms a precoding aided DSM pattern in the first hop and applies incoherent detection in a centralized or distributed manner at the RNs. Based on the decode-and-forward protocol, DSM transmission is carried out in the second hop and achieves high energy efficiency via statistical single RN activation at any time instant. We analyze the performance of DH-HDSM in terms of the average bit error probability and make comparisons with dual-hop hybrid spatial modulation (DH-HSM) and differential VMIMO systems with either a single relay or best relay selection. Theoretical results and Monte Carlo simulations confirm that DH-HDSM outperforms DH-HSM and other differential relay schemes in terms of error performance when the DN is equipped with multiple antennas.
Autors: Meng Zhang;Miaowen Wen;Xiang Cheng;Liuqing Yang;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Sep 2016, volume: 15, issue:9, pages: 6356 - 6370
Publisher: IEEE
 
» A Fair and Efficient Resource Allocation Scheme for Multi-Server Distributed Systems and Networks
Abstract:
Maintaining efficiency and fairness is a challenging problem in distributed systems and networks. In this paper, we focus on distributed multi-server systems and networks in which each user may be allocated resources by different servers. Reemphasizing polling systems as abstractions of resource sharing systems, in this paper, first we introduce a multi-server polling system in which each server (resource) can poll (be allocated to) only a subset of queues (users) in the system to model a wide range of multi-server systems such as multihomed networks and cloud computing. Then, to obtain a fair resource allocation vector to queues, a network utility maximization problem with a general utility function is defined. Depending on the type of the utility function, the presented scheme can attain different kinds of fairness such as weighted proportional and max-min fairness. Although maintaining fairness is important in many applications, providing efficiency is also crucial. Hence, we present an efficient algorithm to convert the obtained fair resource allocation vector into a Markovian routing matrix to determine the polling order of queues. This algorithm is capable of improving performance measures such as delay variance and mitigating short-term unfairness by minimizing the probability of consecutive polling of the same queue. Two distributed schemes are presented to obtain fairness and efficiency in even highly dynamic and distributed environments. The effectiveness of the presented schemes is also studied through simulation and numerical evaluation. Our results show their success in attaining fairness and efficiency in dynamic multi-server distributed systems and networks.
Autors: Peyman Teymoori;Khosrow Sohraby;Kiseon Kim;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Sep 2016, volume: 15, issue:9, pages: 2137 - 2150
Publisher: IEEE
 
» A Film-Profile-Engineered 3-D InGaZnO Inverter Technology With Systematically Tunable Threshold Voltage
Abstract:
In this paper, a new depletion-load metal oxide-based inverter with 3-D structure is realized with film-profile-engineered InGaZnO (IGZO) thin-film transistors (TFTs). The proposed inverter possesses vertically stacked load and drive TFTs whose threshold voltage can be flexibly adjusted into a wide range of −2.3–1 V through merely adjusting the geometric parameters without the necessity of additional processes or masks. The 3-D IGZO inverters constructed through the proposed technology demonstrate full-swing switching with voltage gains up to 19 V/V under an operation voltage of 9 V. The 3-D inverters can not only reduce the footprint but also promote the resistance toward light-induced instability.
Autors: Rong-Jhe Lyu;Horng-Chih Lin;Pei-Wen Li;Tiao-Yuan Huang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2016, volume: 63, issue:9, pages: 3533 - 3539
Publisher: IEEE
 
» A Framework for Co-Channel Interference and Collision Probability Tradeoff in LTE Licensed-Assisted Access Networks
Abstract:
Small cell deployment in heterogeneous networks, whereby small cell base stations (SBS) are deployed alongside traditional macro-cell base stations, is a proven solution for enhancing spatial frequency reuse across licensed spectrum in long-term evolution (LTE) networks. In order to mitigate the shortage of licensed spectrum resources, licensed-assisted access (LAA) has been introduced to allow LTE SBSs to share the unlicensed channel with WiFi nodes. As such, a complex yet interesting optimization problem results from the joint utilization of licensed and unlicensed spectrum resources by the SBSs to meet the quality-of-service (QoS) requirements of small cell users (SUEs). In this paper, we highlight the fundamental tradeoff induced by the SBSs between the amount of co-channel interference (CI) resulting from the reuse of licensed spectrum resources and the collision probability (CP) imposed on the co-existing WiFi nodes due to the sharing of unlicensed spectrum resources in such a coexisting LTE LAA-WiFi heterogeneous network deployment. We find that this fundamental tradeoff can be analyzed by developing a power allocation rule with double water-filling lines and the complete set of Pareto optimal solution can be achieved by the weighted Tchebycheff method. Our simulation results show that the proposed joint resource allocation algorithm can achieve a flexible and suitable tradeoff between the licensed spectrum CI and the WiFi CP according to the QoS requirements of SUEs in LTE LAA networks.
Autors: Rui Yin;Guanding Yu;Amine Maaref;Geoffrey Ye Li;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Sep 2016, volume: 15, issue:9, pages: 6078 - 6090
Publisher: IEEE
 
» A Framework for Joint Design of Pilot Sequence and Linear Precoder
Abstract:
Most performance measures of pilot-assisted multiple-input multiple-output systems are functions of the linear precoder and the pilot sequence. A framework for the optimization of these two parameters is proposed, based on a matrix-valued generalization of the concept of effective signal-to-noise ratio (SNR) introduced in the famous work by Hassibi and Hochwald. Our framework aims to extend the work of Hassibi and Hochwald by allowing for transmit-side fading correlations, and by considering a class of utility functions of said effective SNR matrix, most notably including the well-known capacity lower bound used by Hassibi and Hochwald. We tackle the joint optimization problem by recasting the optimization of the precoder (resp. pilot sequence) subject to a fixed pilot sequence (resp. precoder) into a convex problem. Furthermore, we prove that joint optimality requires that the eigenbases of the precoder and pilot sequence be both aligned along the eigenbasis of the channel correlation matrix. We finally describe how to wrap all studied subproblems into an iteration that converges to a local optimum of the joint optimization.
Autors: Adriano Pastore;Michael Joham;Javier Rodríguez Fonollosa;
Appeared in: IEEE Transactions on Information Theory
Publication date: Sep 2016, volume: 62, issue:9, pages: 5059 - 5079
Publisher: IEEE
 
» A Free-Space Measurement Method for the Low-Loss Dielectric Characterization Without Prior Need for Sample Thickness Data
Abstract:
A free-space measurement method is presented for the characterization of low-loss dielectric materials at millimeter-wave frequencies that does not require any assumption of a priori knowledge of the sample thickness. The method first employs only maximal and minimal envelopes of measured transmission scattering parameters to determine the real part of the permittivity of test materials. Subsequently, the thickness of the sample is estimated from and frequencies for maximal and minimal peaks of the transmission scattering parameter. The calculation of the imaginary part of the permittivity then easily follows. Our method is examined by measuring two cross-linked polystyrene samples, one polytetrafluoroethylene sample and one polymethylpentene sample in the frequency range of 220–325 GHz at the incident angles of 0°, 10°, 20°, and 30°. Moreover, an explicit uncertainty analysis for the permittivity is derived, and uncertainties of the extracted complex permittivity are reported.
Autors: Sung Kim;David Novotny;Joshua A. Gordon;Jeffrey R. Guerrieri;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2016, volume: 64, issue:9, pages: 3869 - 3879
Publisher: IEEE
 
» A Fully Coupled Nonlinear Scheme for Time-Domain Modeling of High-Power Microwave Air Breakdown
Abstract:
In this paper, the air breakdown problem encountered with high-power microwave operation is modeled using a fully coupled nonlinear Newton scheme in the time domain. As a highly nonlinear process, the air breakdown is resulted from the complicated electromagnetic–plasma interactions, which can be described by a coupled system where Maxwell’s equations govern the electromagnetic fields, and a simplified plasma fluid equation governs the plasma current. The resulting nonlinear Maxwell’s equations are solved by the time-domain finite-element method with a proposed Newton’s method, while the simplified plasma fluid equation is solved with another point-wise Newton’s method. These two sets of equations are coupled together using a proposed inner–outer iterative scheme to guarantee the convergence and accuracy of the numerical solution. Numerical examples are presented to characterize the nonlinear phenomenon of the breakdown process and the self-sustaining property of the plasma current.
Autors: Su Yan;Jian-Ming Jin;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Sep 2016, volume: 64, issue:9, pages: 2718 - 2729
Publisher: IEEE
 
» A Fully Integrated Reconfigurable Switched-Capacitor DC-DC Converter With Four Stacked Output Channels for Voltage Stacking Applications
Abstract:
This work presents a fully integrated 4-to-1 DC-DC symmetric ladder switched-capacitor converter (SLSCC) for voltage stacking applications. The SLSCC absorbs inter-layer load power mismatch to provide minimum voltage guarantees for the internal rails of a multicore system that implements four-way voltage stacking. A new hybrid feedback control scheme reduces the voltage ripple across stacked voltage layers for high levels of current mismatch, a condition that exacerbates voltage noise in conventional SC converters. Furthermore, the proposed SLSCC dynamically allocates valuable flying capacitor resources according to different load conditions, which improves conversion efficiency and supports more power mismatch between the layers. Implemented in TSMC’s 40G process, the SLSCC converts a 3.6 V input voltage down to four stacked output voltage layers, each nominally at 900 mV.
Autors: Tao Tong;Sae Kyu Lee;Xuan Zhang;David Brooks;Gu-Yeon Wei;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2016, volume: 51, issue:9, pages: 2142 - 2152
Publisher: IEEE
 
» A Generalized Mixed Effect Kijima Model and Application in Optimal Maintenance Planning
Abstract:
The Kijima model has been widely used in reliability literature to analyze repairable systems with various degrees of repair efficiency including “perfect repair,” “minimal repair,” and situations in between. Most existing studies, however, treat repair efficiency as a fixed value even though repair efficiency can vary among a series of repairs. In this paper, we propose a generalized mixed effect Kijima model to characterize the variation of repair efficiency. In particular, the newly proposed “mixed effect” model incorporates a fixed time-dependent effect and a random effect of repair efficiency, while the term “generalized” refers to the fact that the classic Kijima model is generalized to handle more maintenance situations such as “better than new” and “worse than old” situations after repair. To estimate the model parameters given a series of observed system failure times, we develop a stochastic approximation expectation maximization algorithm which is a type of maximum likelihood estimation method. Further, an optimal periodic maintenance planning is developed based on the proposed reliability model. A simulation study and a real-world case study are conducted to demonstrate the developed methods.
Autors: Wujun Si;Qingyu Yang;
Appeared in: IEEE Transactions on Reliability
Publication date: Sep 2016, volume: 65, issue:3, pages: 1551 - 1561
Publisher: IEEE
 
» A Generalized MPC Framework for the Design and Comparison of VSI Current Controllers
Abstract:
Model predictive control (MPC) has been widely advocated as a design strategy for many aspects of industrial electronics. The methodology has been strongly promoted by some researchers but has also attracted criticism from others. In this context, the purpose of this paper is twofold. First, we show that many existing and popular control strategies, including finite set MPC and linear controllers [proportional integral, proportional resonant (PR)], can be viewed as special cases of MPC. Second, we show that the predictive control framework allows one to embellish these classical control architectures with novel features and to design new and advanced control architectures to address various challenges posed by power electronics applications. The findings of the paper are supported by a practical example of designing of a novel form of PR controller with superior tracking performance and delay compensation, confirmed via simulation and experiments.
Autors: Galina Mirzaeva;Graham Clifford Goodwin;Brendan P. McGrath;Carlos Teixeira;Marco E. Rivera;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Sep 2016, volume: 63, issue:9, pages: 5816 - 5826
Publisher: IEEE
 
» A Generalized Transition Matrix Model for Open-Ended Cavity With Complex Internal Structures
Abstract:
In this paper, a novel generalized transition matrix (GTM) algorithm is proposed to analyze the electromagnetic problems of open-ended cavity structures. An artificial reference surface is applied to seal the slots and/or apertures to reshape the target cavity into an interior domain (containing inner metallic surface and internal structures) and an exterior domain (containing the outer surface of the cavity). Special junctions at the transitional connection of the two domains are applied to guarantee the current continuity on the metallic surface. Based on the Huygens principle, an associated GTM is constructed on the reference surface and the special junctions to extract the characteristics of the interior region of the cavity. The GTM is independent of the outer shape of the cavity and the exterior electromagnetic environment. The computational complexity can be effectively reduced, especially when the interior region is with fine structures and internal sources. To investigate the feasibility and effectiveness of the proposed approach, several numerical examples are presented.
Autors: Shang Xiang;Gaobiao Xiao;Junfa Mao;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2016, volume: 64, issue:9, pages: 3920 - 3930
Publisher: IEEE
 
» A Geometric Programming Solution for the Mutual-Interference Model in HetNets
Abstract:
It is well known that the use of heterogeneous networks and densification strategies will be crucial to handle the wireless cellular traffic increase that is foreseen in the forthcoming years. Hence, the scientific community is putting effort into the proposal and assessment of radio resource management solutions for this type of deployments. For that, an accurate modeling of the underlying resources is mandatory. In this letter, we propose a mutual-interference model, which enables a precise estimation of the signal-to-interference and noise ratio (SINR), compared with the widespread constant-load alternative. This is of utter relevance, since the SINR has a direct influence on the spectral efficiency and, consequently, on the resources to be allocated. We also propose a transformation of the corresponding resource assignment problem, so that it can be solved using geometric programming techniques. The validity of this transformation is assessed by comparing the corresponding solution with the one that would have been obtained exploiting a heuristic approach (simulated annealing).
Autors: Luis Diez;George-Pantelimon Popescu;Ramón Agüero;
Appeared in: IEEE Communications Letters
Publication date: Sep 2016, volume: 20, issue:9, pages: 1876 - 1879
Publisher: IEEE
 
» A Graph-Based Approach to Measuring the Efficiency of an Urban Taxi Service System
Abstract:
Taxi service systems in big cities are immensely complex due to the interaction and self-organization between taxi drivers and passengers. An inefficient taxi service system leads to more empty trips for drivers and longer waiting time for passengers and introduces unnecessary congestion on the road network. In this paper, we investigate the efficiency level of the taxi service system using real-world large-scale taxi trip data. By assuming a hypothetical system-wide recommendation system, two approaches are proposed to find the theoretical optimal strategies that minimize the cost of empty trips and the number of taxis required to satisfy all the observed trips. The optimization problems are transformed into equivalent graph problems and solved using polynomial time algorithms. The taxi trip data in New York City are used to quantitatively examine the gap between the current system performance and the theoretically optimal system. The numerical results indicate that, if system-wide information between taxi drivers and passengers was shared, it is possible to reduce 60%–90% of the total empty trip cost depending on different objectives, and one-third of all taxis required to serve all observed trips. The existence of destructive competition among taxi drivers is also uncovered in the actual taxi service system. The huge performance gap suggests an urgent need for a system reconsideration in designing taxi recommendation systems.
Autors: Xianyuan Zhan;Xinwu Qian;Satish V. Ukkusuri;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Sep 2016, volume: 17, issue:9, pages: 2479 - 2489
Publisher: IEEE
 
» A Haptic Feedback System for Phase-Based Sensory Restoration in Above-Knee Prosthetic Leg Users
Abstract:
Persons with amputations lack important senses from the amputated limb. With the absence of proprioception in the amputated leg, amputees have far more difficulty maintaining a natural gait with balance and stability. The biggest determinant of temporal limb behavior during locomotion is the phase in the gait cycle, which can be estimated using the center of pressure (COP) under the feet. We hypothesize that feedback from the COP of the prosthetic foot can help restore a more robust sense of phase in transfemoral (above-knee) amputees. This paper presents a device that provides vibrotactile feedback based on the COP from the prosthesis, providing proprioception and potentially an improved sense of phase to the user. Experiments showed that the haptic device significantly decreased variability of stride length, step width, and trunk sway in novice (able-bodied) users of a transfemoral prosthetic leg during treadmill locomotion (N=9), indicating improved gait stability.
Autors: Aaron Plauché;Dario Villarreal;Robert D. Gregg;
Appeared in: IEEE Transactions on Haptics
Publication date: Sep 2016, volume: 9, issue:3, pages: 421 - 426
Publisher: IEEE
 
» A Helping Hand: Soft Orthosis with Integrated Optical Strain Sensors and EMG Control
Abstract:
Human fingers and hands are frequently injured because they are delicate, complex, and used constantly. More than 3 million people in the United States suffer from hand or forearm disabilities [1], and, worldwide, hand injuries account for one-third of all work injuries [2]. Due to the importance of hands and the prevalence of hand issues, there is an increasing effort toward developing hand orthotics. These efforts have resulted in active hand orthoses that have been used for rehabilitation training and restoring partial hand function [3]. To ensure safety and to reduce control complexity, some orthoses use mechanical compliances [4], [5] such as underactuated linkages [6] or low-stiffness materials and structures (e.g., rubbers and flexible wires) [7], [8]-[11]. The orthoses made of elastomeric materials tend to be more comfortable, perhaps because their low elastic modulus (10 kPa < G' < 1 MPa) [12] is similar to that of human skin (~100 kPa) [13].
Autors: Huichan Zhao;Jonathan Jalving;Rukang Huang;Ross Knepper;Andy Ruina;Robert Shepherd;
Appeared in: IEEE Robotics & Automation Magazine
Publication date: Sep 2016, volume: 23, issue:3, pages: 55 - 64
Publisher: IEEE
 
» A Heuristic Force Model for Haptic Simulation of Nasogastric Tube Insertion Using Fuzzy Logic
Abstract:
Nasogastric tube (NGT) placement is an essential clinical skill. The training is conventionally performed on rubber mannequins albeit practical limitations. Computer simulation with haptic feedback can potentially offer a more realistic and accessible training method. However, the complex interactions between the tube and the nasogastric passage make it difficult to model the haptic feedback during NGT placement. In this paper, a fuzzy-logic-based approach is proposed to directly transfer the experience of clinicians in NGT placement into the simulation system. Based on their perception of the varying tactile sensation and the conditions during NGT placement, the membership functions and fuzzy rules are defined to develop the force model. Forces created using the model are then combined with friction forces to drive the haptic device and render the insertion forces in real time. A prototype simulator is developed based on the proposed force model and the implementation details are presented. The usability of the prototype is also evaluated by clinical teachers. The proposed methodology has the potential for developing computerized NGT placement training methods for clinical education. It is also applicable for simulation systems involving complicated force interactions or computation-expensive models.
Autors: Kup-Sze Choi;Xue-Jian He;Vico C.L. Chiang;Zhaohong Deng;Jing Qin;
Appeared in: IEEE Transactions on Haptics
Publication date: Sep 2016, volume: 9, issue:3, pages: 295 - 310
Publisher: IEEE
 
» A High Dynamic Range Power Detector at X-Band
Abstract:
This letter presents an X-band power detector in a 0.25- SiGe BiCMOS technology which utilizes a novel technique, cascode configuration with diode connected PMOS load that provides high responsivity, high dynamic range and wideband input matching for various input powers. This configuration achieves a dynamic range of 52 dB, which is the highest dynamic range for a single stage X-band power detector to the best of author's knowledge. The total chip area is 0.42 mm2, including pads. Total power consumption is 7.2 mW. Results demonstrate that such a power detector can be used for built-in digital self calibration of X-band front-end circuits.
Autors: Emre Ozeren;Ilker Kalyoncu;Berktug Ustundag;Barbaros Cetindogan;Huseyin Kayahan;Mehmet Kaynak;Yasar Gurbuz;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Sep 2016, volume: 26, issue:9, pages: 708 - 710
Publisher: IEEE
 
» A High-Level Thermal Model-Based Task Mapping for CMPs in Dark-Silicon Era
Abstract:
The chip multiprocessor (CMP) thermal issue impacting the system reliability and cooling cost has become a limiting factor for chip scaling and attracted growing attentions in the dark-silicon era. We propose a thermal-aware thread-to-core mapping method for CMPs under the dark-silicon constraint. We first propose a high-level spatial-temporal information-based thermal model to capture the relationship between the mapping result and the system thermal distribution. Then, we develop a thermal-aware mapping algorithm, which can automatically assign threads to proper cores based on the proposed model. Finally, we evaluate our method through simulations. Compared with three other mapping methods, namely, random, network-on-chip (NoC)-sprinting and round-robin, our thermal-priority design decreases the peak temperature by up to 4.31 K while showing good communication performance (34.7% of improvement against random and 50.3% against NoC sprinting, and only 6.3% of degradation against round robin); and our latency-priority design achieves the best communication performance with an improvement up to 62.6% and a satisfactory thermal profile.
Autors: Jian Wang;Zhonghai Lu;Yubai Li;Yusheng Fu;Jinhong Guo;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2016, volume: 63, issue:9, pages: 3406 - 3412
Publisher: IEEE
 
» A Highly Integrated 60 GHz 6-Channel Transceiver With Antenna in Package for Smart Sensing and Short-Range Communications
Abstract:
This work presents a highly integrated 57–64 GHz 4-channel receiver 2-channel transmitter chip targeting short range sensing and large bandwidth communications. The chip is housed in an embedded wafer level ball grid array package. The package includes 6 integrated patch antennas realized with a metal redistribution layer. The receiver patch antennas have a combined antenna gain of dBi while each transmitter antenna has a gain of dBi. The chip features a wide tuning range integrated VCO with a measured phase noise lower than −80 dBc/Hz at 100 kHz offset. Each of the differential transmitter channels shows a measured output power of 2–5 dBm over the complete frequency range. In addition, one transmitter channel features a modulator that can be digitally programmed to operate in either radar or communication mode. Each of the receiver channels has a measured conversion gain of 19 dB, a single-sideband noise figure of less than 10 dB and an input referred 1 dB compression point of less than 10 dBm. With all channels turned on the chip consumes a current of 300 mA from a 3.3 V supply. The functionality of the chip is demonstrated for both sensing and short range wireless communications.
Autors: Ismail Nasr;Reinhard Jungmaier;Ashutosh Baheti;Dennis Noppeney;Jagjit S. Bal;Maciej Wojnowski;Emre Karagozler;Hakim Raja;Jaime Lien;Ivan Poupyrev;Saverio Trotta;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2016, volume: 51, issue:9, pages: 2066 - 2076
Publisher: IEEE
 
» A Highly Reliable Memory Cell Design Combined With Layout-Level Approach to Tolerant Single-Event Upsets
Abstract:
In this paper, a highly reliable radiation hardened by design memory cell (RHD12) using 12 transistors in a 65-nm CMOS commercial technology is proposed. Combining with layout-level design, the TCAD mixed-mode simulation results indicate that the RHD12 not only can fully tolerant the single-event upset occurring on any one of its single nodes but can also tolerant single-event multiple-node upsets in a single memory cell, which are caused by charge sharing. Moreover, a set of HSPICE post-simulations are done to evaluate the RHD12 and other state-of-the-art memory cells, which show that our proposed memory cell has better performance, considering the area, power consumption, and access time.
Autors: Chunhua Qi;Liyi Xiao;Tianqi Wang;Jie Li;Linzhe Li;
Appeared in: IEEE Transactions on Device and Materials Reliability
Publication date: Sep 2016, volume: 16, issue:3, pages: 388 - 395
Publisher: IEEE
 
» A Hybrid 2-D/3-D Multilevel Green’s Function Interpolation Method for Electrically Large Multilayered Problems
Abstract:
The multilevel Green’s function interpolation method has been implemented to solve the general electrically-large multilayered problems. A new hybrid 2-D and 3-D (H2-D/3-D) multilevel interpolation method and a cross-level translation scheme are devised for the specific problems, from which a quad-tree is constructed. The interpolation of the multilayered medium Green’s function using radial basis function is then studied. To further accelerate the computation, a subdomain fast Fourier transform scheme and a sparse approximated inverse preconditioner with a new discarding strategy are also incorporated into the algorithm. As numerical examples, typical microstrip antenna arrays, a metasurface antenna and electromagnetic bandgap integrated antenna arrays are analyzed with the proposed method and excellent performance is observed in both accuracy and efficiency.
Autors: Peng Zhao;Da Qing Liu;Chi Hou Chan;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2016, volume: 64, issue:9, pages: 3931 - 3942
Publisher: IEEE
 

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