Electrical and Electronics Engineering publications abstract of: 03-2017 sorted by title, page: 2

» A Reconstruction–Registration Integrated Data Fusion Method for Measurement of Multiscaled Complex Surfaces
Abstract:
The combined use of multiple measurement sensors is considered as a promising solution in surface metrology. Such hybrid instruments require sophisticated data fusion process to achieve overall better measurement results. This paper presents a reconstruction–registration integrated data fusion method to address the difficulty in modeling and fusing multiscaled complex data sets. The method decomposes the data sets into different scales by fitting a common surface via reconstruction and registration process so that the modeling and fusion process are also decomposed, and are only performed among the fitting and matching residuals of the data sets. The quality of the fused results is improved based on weighted mean method with the aid of Gaussian process model by taking into account the associated errors of each data set. The validity of the proposed method is verified through a series of comparison tests with existing methods by both computer simulation and actual measurement. It is shown that both enhanced registration accuracy and fusion quality are achieved by the proposed method with acceptable computation cost. The method should improve the metrological performance of the multisensor instruments in measuring complex surfaces.
Autors: Ming Jun Ren;Li Jian Sun;Ming Yu Liu;Chi Fai Cheung;Yue Hong Yin;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Mar 2017, volume: 66, issue:3, pages: 414 - 423
Publisher: IEEE
 
» A Regulated Charge Pump for Tunneling Floating-Gate Transistors
Abstract:
Flash memory is an important component in many embedded system-on-a-chip applications, which drives the need to generate high write/erase voltages in generic CMOS processes. In this paper, we present a regulated, high-voltage charge pump for erasing Flash memory and floating-gate transistors. This 0.069-mm2 charge pump was fabricated in a 0.35 standard CMOS process. While operating from a 2.5 V supply, the charge pump generates regulated voltages up to 16 V with a PSRR of 52 dB and an output impedance of 6.8 . To reduce power consumption for use in battery-powered applications, this charge pump uses a variable-frequency regulation technique and a new circuit for minimizing short-circuit current in the clock-generation circuitry; the resulting charge pump is able to erase the charge on floating-gate transistors using only .
Autors: Brandon Rumberg;David W. Graham;Mir Mohammad Navidi;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Mar 2017, volume: 64, issue:3, pages: 516 - 527
Publisher: IEEE
 
» A Revolution on the Horizon from DARPA: Heterogeneous Integration for Revolutionary Microwave/Millimeter-Wave Circuits at DARPA: Progress and Future Directions
Abstract:
The Microsystems Technology Office of the U.S. Defense Advanced Research Projects Agency (DARPA) is developing revolutionary materials, devices, and integration techniques to meet the performance requirements for advanced microwave and millimeter-wave (mmW) systems. The DARPA Compound Semiconductor Materials on Silicon (COSMOS) program focused on developing new methods to tightly integrate compound semiconductor (CS) technologies within state-of-the-art silicon (Si) complementary?metal-oxide-semiconductor (CMOS) circuits to achieve unprecedented circuit performance levels. The DARPA Diverse Accessible Heterogeneous Integration (DAHI) program is continuing that work by developing heterogeneous integration processes to intimately combine advanced CS devices, as well as other emerging materials and devices, with high-density Si CMOS technology. DARPA has also pushed limits in Si technology and driven seminal developments in gallium nitride (GaN) device technology. Taken together, these programs are addressing many critical challenges for next-generation microwave and mmW systems and seek to revolutionize U.S. Department of Defense (DoD) capabilities in these areas.
Autors: Daniel S. Green;Carl L. Dohrman;Jeffrey Demmin;Yan Zheng;Tsu-Hsi Chang;
Appeared in: IEEE Microwave Magazine
Publication date: Mar 2017, volume: 18, issue:2, pages: 44 - 59
Publisher: IEEE
 
» A Robust Parameterization of Human Gait Patterns Across Phase-Shifting Perturbations
Abstract:
The phase of human gait is difficult to quantify accurately in the presence of disturbances. In contrast, recent bipedal robots use time-independent controllers relying on a mechanical phase variable to synchronize joint patterns through the gait cycle. This concept has inspired studies to determine if human joint patterns can also be parameterized by a mechanical variable. Although many phase variable candidates have been proposed, it remains unclear which, if any, provide a robust representation of phase for human gait analysis or control. In this paper we analytically derive an ideal phase variable (the hip phase angle) that is provably monotonic and bounded throughout the gait cycle. To examine the robustness of this phase variable, ten able-bodied human subjects walked over a platform that randomly applied phase-shifting perturbations to the stance leg. A statistical analysis found the correlations between nominal and perturbed joint trajectories to be significantly greater when parameterized by the hip phase angle (0.95+) than by time or a different phase variable. The hip phase angle also best parameterized the transient errors about the nominal periodic orbit. Finally, interlimb phasing was best explained by local (ipsilateral) hip phase angles that are synchronized during the double-support period.
Autors: Dario J. Villarreal;Hasan A. Poonawala;Robert D. Gregg;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Mar 2017, volume: 25, issue:3, pages: 265 - 278
Publisher: IEEE
 
» A SaaS Framework for Credit Risk Analysis Services
Abstract:
Credit Risk Analysis (CRA) software services are becoming very important nowadays due to the financial crisis. Adapting the existing Enterprise Resource Planning (ERP) systems to include CRA services commonly involves a high cost, mainly caused by particular requirements of each company. On contrary, the CRA systems not included in the company ERP still require the ERP data. In this paper we describe OneRate, a Software as a Service (SaaS) CRA solution. OneRate frees the companies from the cost of adapting their current ERPs and from maintaining a separate CRA product. Our solution is highly customizable to the particular needs of each client company, so that customers benefit from the existing CRA capabilities while they also have a personalized product. OneRate is currently supporting more than 300 users of 32 different companies.
Autors: Jose Manuel Redondo;Francisco Ortin;
Appeared in: IEEE Latin America Transactions
Publication date: Mar 2017, volume: 15, issue:3, pages: 474 - 481
Publisher: IEEE
 
» A Scalable Performance–Complexity Tradeoff for Constellation Randomization in Spatial Modulation
Abstract:
It is widely recognized that traditional single radio frequency (RF)-chain-aided spatial modulation (SM) does not offer any transmit diversity gain. As a remedy, constellation randomization (CR), relying on transmit prescaling (TPS), has been shown to provide transmit diversity for single-RF-chain-aided SM. In this paper, we propose a low-complexity approach to SM with the aid of constellation randomization (SM-CR) that considerably improves the transmit diversity gain of SM at a reduced computational burden compared with conventional SM-CR. While conventional SM-CR performs a full search among a set of candidate TPS factors to achieve the maximum minimum Euclidean distance (MED) in the received SM constellation, here, we propose a thresholding approach, where, instead of the maximum MED, the TPS aims to satisfy a specific MED threshold. This technique offers a significant complexity reduction with respect to the full maximization of SM-CR, since the search for TPS is terminated once a TPS set is found that satisfies the MED threshold. Our analysis and results demonstrate that a scalable tradeoff can be achieved between transmit diversity and complexity by appropriately selecting the MED threshold, where a significant complexity reduction is attained, while achieving a beneficial transmit diversity gain for the single-RF SM.
Autors: Christos Masouros;Lajos Hanzo;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2834 - 2838
Publisher: IEEE
 
» A Scalable Solution to Soft Error Tolerant Circuit Design Using Partitioning-Based Gate Sizing
Abstract:
Current technology scaling trends aggressively increases the susceptibility of combinational circuit reliability to radiation-induced transient faults (which also known as soft errors). Various gate sizing techniques have been used to reduce soft error rate (SER) in the past, but their main drawback is that they are expensive in term of run time. These methods require changes to adapt to the large scale circuits. In this paper, an efficient circuit partitioning-based gate sizing method is presented, which significantly speeds up the gate sizing optimization process. In the proposed method, the circuit is divided into the topologically levelized small subcircuits by cone structures. Then, the subcircuits which are located in the same level are resized individually and independently. The subcircuit error probability (SEP) metric is introduced to evaluate the contribution of each subcircuit into the total circuit SER. The key idea of the proposed method is to evaluate the effects of each gate sizing on circuit reliability locally using SEP instead of global evaluation by the total circuit SER. Such evaluation results in speeding up the gate sizing optimization process. Experimental results show that the proposed approach is about 280× orders of magnitude faster than the sensitivity-based gate sizing approach [R. R. Rao, D. Blaauw, and D. Sylvester, “Soft error reduction in combinational logic using gate resizing and flipflop selection,” in Proc. IEEE/ACM Int. Conf. Comput.-Aided Des., 2006, pp. 502–509] while it can achieve up to 45% reduction in circuit SER with less than 17% area overhead. This level of speed and efficiency makes the proposed approach a viable solution to mitigate the SER of very large combinational circuits used in industry.
Autors: M. Amin Sabet;Behnam Ghavami;Mohsen Raji;
Appeared in: IEEE Transactions on Reliability
Publication date: Mar 2017, volume: 66, issue:1, pages: 245 - 256
Publisher: IEEE
 
» A Self-Adaptive Inertia and Damping Combination Control of VSG to Support Frequency Stability
Abstract:
In the virtual synchronous generator (VSG) field, the traditional methods, such as the constant parameters control method and the self-adaptive inertia control method, always neglect the effect of the damping factor. This letter proposes a self-adaptive inertia and damping combination control method to improve the frequency stability with an interleaving control technique. Tests on the MATLAB/Simulink VSG model demonstrate the effectiveness of the proposed method.
Autors: Dongdong Li;Qianwei Zhu;Shunfu Lin;X. Y. Bian;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Mar 2017, volume: 32, issue:1, pages: 397 - 398
Publisher: IEEE
 
» A Self-Powered 50-Mb/s OOK Transmitter for Optoisolator LED Emulation
Abstract:
Isolators are used to eliminate ground loops, and also to protect circuits that are sensitive to high voltages. Optoisolators are normally deployed for these purposes, but they suffer from several limitations, such as low speed of operation and temperature instability. In this paper, an ON–OFF keying (OOK) transmitter (TX) is designed so as to emulate and serve as an alternative to optoisolators, without significant changes to the rest of the system. The TX primarily consists of a voltage clamp circuit to convert input current into voltage, a discharge circuit to avoid metastability, and a 300–700-MHz spread-spectrum (SS) oscillator. The start-up and die-down times of the oscillator are optimized for maximum data speed. SS modulation of the oscillator output restricts radiative emissions to within permissible limits. The TX derives power from the input data (current) signal itself, thereby operating without any external power supply, and supports speeds of up to 50 Mb/s. The TX was fabricated in a BiCMOS semiconductor process and tested using an OOK receiver.
Autors: Sreenivasa Mallia S;Sreeram NS;Sudhir Komarla Adinarayana;Sankaran Aniruddhan;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Mar 2017, volume: 52, issue:3, pages: 678 - 687
Publisher: IEEE
 
» A Self-Powered and Optimal SSHI Circuit Integrated With an Active Rectifier for Piezoelectric Energy Harvesting
Abstract:
This paper presents a piezoelectric energy harvesting circuit, which integrates a Synchronized Switch Harvesting on Inductor (SSHI) circuit and an active rectifier. The major design challenge of the SSHI method is flipping the capacitor voltage at optimal times. The proposed SSHI circuit inserts an active diode on each resonant loop, which ensures flipping of the capacitor voltage at optimal times and eliminates the need to tune the switching time. The diodes of the SSHI circuit are also used as a rectifier to further simplify the controller. The key advantage of the proposed circuit is a simple controller, which leads to low power dissipation of the proposed circuit to result in high efficiency. The proposed circuit is self-powered and capable of starting even when the battery is completely drained. The circuit was fabricated in BiCMOS technology with a die size of mm2. Measured results indicate that the proposed circuit increases the amount of power harvested from a piezoelectric cantilever by 2.1 times when compared with a full bridge (FB) rectifier and achieves a power conversion efficiency of 85%. The proposed circuit dissipates about while the controller alone only .
Autors: Liao Wu;Xuan-Dien Do;Sang-Gug Lee;Dong Sam Ha;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Mar 2017, volume: 64, issue:3, pages: 537 - 549
Publisher: IEEE
 
» A Simple and Effective Inverse Source Reconstruction With Minimum A Priori Information on the Source
Abstract:
A simple and effective two-step method to detect and localize scattering objects from the measurements of the total electric field, collected at a single frequency on a planar domain, is presented. The first step consists in solving a linear inverse source problem, looking for surface equivalent currents on a plane located between the measurement surface and the objects themselves. Thus, the equivalent currents associated with both the scatterer presence and the background contribution are obtained. In the second step, the support of the equivalent currents associated with the objects is separated from the background by exploiting the low-rank property of the background field. The proposed method does not require information on the source, except for its frequency, and it is easily implementable and entails a low computational burden. Experimental results validate the method.
Autors: Adriana Brancaccio;Marco Donald Migliore;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Mar 2017, volume: 14, issue:3, pages: 454 - 458
Publisher: IEEE
 
» A Simple Solution for the Phase Offset Estimation of Airborne SAR Interferograms Without Using Corner Reflectors
Abstract:
We present a solution for simplifying a recently proposed two-step processing technique that allows to retrieve the constant phase offset present in the unwrapped synthetic aperture radar (SAR) interferograms by exploiting an external, even low-accuracy, digital elevation model (DEM) of the illuminated area and without using corner reflectors. In particular, we show in this letter that the second processing step, namely, the slope-topography-based estimate, can be avoided without impairing the accuracy of the final phase offset estimate. To this aim, we introduce a simple modification to the first step, referred to as phase-based estimate, by considering the vertical bias of the available external DEM as the second unknown parameter in the carried out estimation. The simplified algorithm is very easy to implement and is particularly suitable for airborne SAR interferometry. It has been tested on real airborne SAR data and the obtained results show that the achieved accuracy is the same or better than that achieved through the original two-step approach.
Autors: Carmen Esposito;Antonio Pauciullo;Paolo Berardino;Riccardo Lanari;Stefano Perna;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Mar 2017, volume: 14, issue:3, pages: 379 - 383
Publisher: IEEE
 
» A Simplified Sparse Parameter Identification Algorithm Suitable for Power Amplifier Behavioral Modeling
Abstract:
In this letter, a simplified sparse parameter identification algorithm is proposed to estimate the coefficients of the power amplifier (PA) behavioral model. The main idea is to select the kernel one by one from the complete model, where the criteria of selection are according to the projection of the residual vector on each kernel. By using this kernel selection method, all sparse parameters can be obtained quickly without any matrix inversion operation. The proposed algorithm is applied to prune dynamic deviation reduction-based Volterra model for a gallium-nitride (GaN) PA. Moreover, the performance and computation complexity of the proposed method are analyzed and compared with existing algorithms.
Autors: Jun Peng;Songbai He;Zhijiang Dai;Bingwen Wang;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Mar 2017, volume: 27, issue:3, pages: 290 - 292
Publisher: IEEE
 
» A Single-Letter Upper Bound on the Feedback Capacity of Unifilar Finite-State Channels
Abstract:
An upper bound on the feedback capacity of unifilar finite-state channels (FSCs) is derived. A new technique, called the -context mapping, is based on a construction of a directed graph that is used for a sequential quantization of the receiver’s output sequences to a finite set of contexts. For any choice of -graph, the feedback capacity is bounded by a single-letter expression, , where the supremum is over and the distribution of is their stationary distribution. It is shown that the bound is tight for all unifilar FSCs, where feedback capacity is known: channels where the state is a function of the outputs, the trapdoor channel, Ising channels, the no-consecutive-ones input-constrained erasure channel, and the memoryless channel. Its efficiency is also demonstrated by deriving a new capacity result for the dicode erasure channel; the upper bound is obtained directly from the above-mentioned expression and its tightness is concluded with a general sufficient condition on the optimality of the upper bound. This sufficient condition is based on a fixed point principle of the BCJR equation and, indeed, formulated as a simple lower bound on feedback capacity of unifilar FSCs for arbitrary -graphs. This upper bound indicates that a single-letter expression might exist for the capacity of finite-state channels with or without feedback based on a construction of auxiliary random variable with specified structure, suc as the -graph, and not with i.i.d distribution. The upper bound also serves as a non-trivial bound on the capacity of channels without feedback, a problem that is still open.
Autors: Oron Sabag;Haim H. Permuter;Henry D. Pfister;
Appeared in: IEEE Transactions on Information Theory
Publication date: Mar 2017, volume: 63, issue:3, pages: 1392 - 1409
Publisher: IEEE
 
» A Single-Phase Five-Level Inverter Topology With Switch Fault-Tolerance Capabilities
Abstract:
Low reliability is one of the major concerns of multilevel inverter due to the requirement of a large number of semiconductor devices as compared to two-level inverters. Thus, in this paper, a novel topology of multilevel inverter is proposed that can tolerate both open and short-circuit faults on its switches. The proposed topology also reduces dc sources and capacitors as compared to the conventional and recently proposed fault-tolerant topologies. Two types of solutions are provided in order to make the proposed topology fault tolerant; first provides a partial solution to fault, while the second provides a complete solution to fault. In addition, a novel switching strategy is proposed to reduce the amount of capacitor voltage ripples under normal and postfault conditions. Also, the proposed switching scheme offers an additional advantage of self-voltage balancing of its capacitor voltage both under normal as well as postfault conditions. To validate the proposed concepts, simulation and experimental analysis are carried out and different results are presented to show the viability of the proposed topology under normal operation, during fault and postfault conditions.
Autors: Shivam Prakash Gautam;Lalit Kumar;Shubhrata Gupta;Nitesh Agrawal;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2004 - 2014
Publisher: IEEE
 
» A Single-Phase Grid-Connected Photovoltaic Inverter Based on a Three-Switch Three-Port Flyback With Series Power Decoupling Circuit
Abstract:
In this paper, a novel single-stage three-port inverter that connects photovoltaic (PV) panel to a single-phase power grid is introduced. In a single-phase grid-connected PV panel, the input power is constant during the line-frequency period, while the output power oscillates at double-line frequency. A series active power decoupling circuit utilizing thin-film capacitors is incorporated to a conventional flyback inverter to handle input and output power differences. Therefore, popularly low-reliable electrolytic capacitors are replaced with small long-lifetime thin film. The proposed inverter can extract the maximum power from PV, deliver a low total harmonic distortion sinusoidal current to the output, and decouple the input and output powers. The proposed power decoupling circuit shares the inverter main switch. Thus, these functions are achieved using just three switches and a simple control scheme which is applicable for both charging and discharging states. Operation principle and control strategy are discussed in detail. Experimental results based on a 100-W prototype inverter verify feasibility and functionality of the proposed inverter.
Autors: Mohammad Hadi Zare;Mustafa Mohamadian;Reza Beiranvand;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2062 - 2071
Publisher: IEEE
 
» A Single-Stage Grid-Connected High Gain Buck–Boost Inverter With Maximum Power Point Tracking
Abstract:
Converter system that does both dc–dc conversion and dc–ac conversion in a single stage is called a single-stage converter system (SSCS). Compared to a two-stage converter, SSCS is more efficient and compact in size. In this paper, a grid-connected SSCS (GCSS) system for photovoltaic (PV) applications is presented. This GCSS transfers power from PV to grid while tracking maximum power point (MPP) continuously. The proposed system has several desirable features such as low switching loss, high gain, and compact size that makes this GCSS suitable for PV systems, where the PV system output voltage is low and varies with time. Design of the presented GCSS components with necessary equations and derivation of both current control loop and voltage control loop required for operation are given. Proposed GCSS is simulated using MATLAB/SIMULINK. Detailed simulation and experimental results are given to verify the efficacy of the proposed GCSS.
Autors: T. Sreekanth;N. Lakshminarasamma;Mahesh K. Mishra;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Mar 2017, volume: 32, issue:1, pages: 330 - 339
Publisher: IEEE
 
» A Small Probe-Type Flowmeter Based on the Differential Fiber Bragg Grating Measurement Method
Abstract:
A small probe-type optical fiber flowmeter was proposed for fluid flow measurement. The hollow cylindrical cantilever was first used to measure the force caused by fluid. A couple of fiber Bragg gratings (FBGs) that were stuck on the inner wall were used to measure the strain of the cantilever. The flow rate can be obtained by monitoring the difference of the two shifted Bragg wavelengths. The cross-sensitivity problem of FBG sensors can be solved by the differential FBG measurement method. Theoretical relation between the Bragg wavelength shift difference and flow rate has been established by theoretical analysis. Meanwhile, experiments have been carried out to verify the feasibility and stability. The simulation and experiment results showed that the resolution of the proposed flowmeter was 0.81 /h and the accuracy was 3.6% in the region of 0–22.5 /h. Compared with the references existed, the proposed flowmeter in this paper was more compact with good sensitivity, wide measurement range, easy fabrication, and low pressure loss.
Autors: Yong Zhao;Ya-Fei Gu;Ri-Qing Lv;Yang Yang;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Mar 2017, volume: 66, issue:3, pages: 502 - 507
Publisher: IEEE
 
» A Space-Time Coding Scheme With Time and Frequency Comb-Like Chirp Waveforms for MIMO-SAR
Abstract:
A new space-time coding (STC) scheme for multiple-input multiple-output synthetic aperture radar systems is proposed in this paper. In the new scheme, two successive signal periods are put into one transmit duration to minimize the time-variant channel effect. The even and odd components of the transmitted waveforms are modulated into distinct Doppler frequencies in the azimuth direction and can be separated by bandpass filter in the range-Doppler domain. The presented STC scheme can suppress the interchannel ambiguous energy caused by the time-variant channel responses, which typically occur in conventional STC schemes, and increase the signal-to-noise ratio of the echoes by a decoding matrix. To further suppress the interference, a waveform called time and frequency comb-like chirp (TFCC) is proposed. With the application of the complementary comb-like structure in the time and frequency domains, two TFCC waveforms are short-term shift-orthogonal and constant envelope. Moreover, these corresponding TFCC waveforms can share the same antenna and time gate without sacrificing any TFCC waveforms’ peak level. The theoretical analysis and simulation results illustrate the feasibility of the proposed scheme.
Autors: Shangwen Liu;Zenghui Zhang;Wenxian Yu;
Appeared in: IEEE Journal of Selected Topics in Signal Processing
Publication date: Mar 2017, volume: 11, issue:2, pages: 391 - 403
Publisher: IEEE
 
» A Structured Grid Finite-Element Method Using Computed Basis Functions
Abstract:
Structured (e.g., rectangular) meshes in finite-element (FE) analysis offer several advantages, but are not often used because of the error introduced in fitting material interfaces. The nonconforming voxel FE method (NVFEM) is a hierarchical structured method that systematically reduces the geometric error in an adaptive way, but it requires large numbers of elements and therefore is expensive. By computing basis functions that take into account the interface cutting through an element, the number of elements needed is greatly reduced. The resulting method, CBF-NVFEM, is applied to the computation of the radar cross section of free-space scatterers. Results indicate that CBF-NVFEM is much more efficient than NVFEM and is competitive with FEM using unstructured meshes of tetrahedra.
Autors: Moein Nazari;Jon P. Webb;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Mar 2017, volume: 65, issue:3, pages: 1215 - 1223
Publisher: IEEE
 
» A Study for Starting Characteristic Analysis Method of Salient Pole Synchronous Motors
Abstract:
Solid rotors can be adapted to synchronous motors of 5 MW and over in applications with high inertia loads. The eddy currents induced in the solid pole are used for starting of the motor and their paths are changed depending on the design of the rotor shape unlike the synchronous motors with damper windings or cages. In this paper, the starting characteristic of a 7-MW solid salient pole synchronous motor is analyzed by the combined methods for 2-D and 3-D finite-element models because a 3-D analysis to solve the problem is difficult due to the long solving time. The maximum difference between results of the combined method for 2-D and 3-D finite-element analysis and the factory test is less than 10%.
Autors: Rakwon Son;Moojong Jeon;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Mar 2017, volume: 53, issue:2, pages: 1627 - 1634
Publisher: IEEE
 
» A Study of Electrical Resistance in Carbon Nanotube–Insulator–Metal Diode Arrays for Optical Rectenna
Abstract:
Vertical tunnel diode arrays made from multiwall carbon nanotubes (MWCNTs) have shown recent promise for developing a practical optical rectenna, which is a device to convert electromagnetic waves at optical frequencies to direct current. Realizing an optical rectenna requires an antenna to be coupled to a diode that operates on the order of PHz (switching speed on the order of fs). Previously, we have demonstrated an optical rectenna device by engineering MWCNT–insulator–metal (MWCNT–I–M) tunnel diodes at the tips of vertically aligned MWCNT arrays, which act collectively as the antenna. However, the high electrical resistance of the MWCNT–I–M diode must be reduced to enable improved impedance matching between diode and antenna, which limited the rectified power in our prior work. Here, we address this issue of impedance mismatch through a series of experiments designed to elucidate contributions to the total electrical resistance of the device. Different combinations of metals, and metal and insulator thicknesses were tested for reduced contact resistance, while maintaining a working diode. Another development toward reducing resistance was to open MWCNT tips using oxygen plasma, which exposed multiple walls for bonding rather than just outer wall of closed tip CNTs. These developments were combined to reduce zero-bias resistance of MWCNT–I–M diode arrays to as low as 100 Ω ·cm2, which is 75 times lower than in our previous report.
Autors: Etizaz Hassan Shah;Billyde Brown;Baratunde A. Cola;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Mar 2017, volume: 16, issue:2, pages: 230 - 238
Publisher: IEEE
 
» A Sub-Nyquist, Variable Sampling, High-Frequency Phased Array Beamformer
Abstract:
A digital receive beamformer implementing a “one sample per pixel” variable sampling technique is described. The sampling method reduces the required sampling rates by a factor of 3, and reduces the data capture rate by a factor of 2, in comparison with the previous systems based on variable sampling. The sampling method is capable of estimating broadband pulse envelopes accurate for bandwidths up to 83.0%. This beamforming method has been implemented on a field-programmable gate array with maximum transmit and receive delay errors measured to be less than ±1.0 ns. The beamformer was tested and verified on a previously described 45-MHz 64-element phased array. The system generates images with 128 lines, 512 pixels per RF line, and 2 transmit focal zones. The system generates images with approximately 55 dB of dynamic range and was tested by imaging wire targets submersed in a water bath, wire targets embedded in a tissue phantom, and real-time in vivo imaging of a human wrist.
Autors: Christopher A. Samson;Andre Bezanson;Jeremy A. Brown;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Mar 2017, volume: 64, issue:3, pages: 568 - 576
Publisher: IEEE
 
» A Success Story : The Value of the Massachusetts Technical Standards Review Group
Abstract:
The Commonwealth of Massachusetts has played a significant role in deploying renewable energy in the United States. In 2013, former Governor Deval Patrick announced an ambitious state goal of 1.6 GW of solar generation to be installed by 2020. This announcement was made after the state achieving its goal of 250 MW of solar energy four years early. The current governor, Charlie Baker, and his administration have also been very ambitious to reduce the greenhouse gas emissions.
Autors: Babak Enayati;
Appeared in: IEEE Power and Energy Magazine
Publication date: Mar 2017, volume: 15, issue:2, pages: 57 - 60
Publisher: IEEE
 
» A Sufficient Condition on Convex Relaxation of AC Optimal Power Flow in Distribution Networks
Abstract:
This paper proposes a sufficient condition for the convex relaxation of ac optimal power flow (OPF) in radial distribution networks as a second order cone program (SOCP) to be exact. The condition requires that the allowed reverse power flow is only reactive or active, or none. Under the proposed sufficient condition, the feasible sub-injection region (power injections of nodes excluding the root node) of the ac OPF is convex. The exactness of the convex relaxation under the proposed condition is proved through constructing a group of monotonic series with limits, which ensures that the optimal solution of the SOCP can be converted to an optimal solution of the original ac OPF. The efficacy of the convex relaxation to solve the ac OPF is demonstrated by case studies of an optimal multi-period planning problem of electric vehicles in distribution networks.
Autors: Shaojun Huang;Qiuwei Wu;Jianhui Wang;Haoran Zhao;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 1359 - 1368
Publisher: IEEE
 
» A Suite of Ontologies for Robotics and Automation [Industrial Activities]
Abstract:
Reports on the formation and activities undertaken by the Ontologies for Robotics and Automation (ORA) Working Group. ORA was established in 2011 by the IEEE Standard Association's Robotics Society. The goal of the group is to develop a standard to provide an overall ontology and associated methodology for knowledge representation and reasoning in robotics and automation together with the representation of concepts in an initial set of application domains. The standard provides a unified way of representing knowledge and provides a common set of terms and definitions, allowing for unambiguous knowledge transfer among any group of human, robots, and other artificial systems.
Autors: Sandro Rama Fiorini;Julita Bermejo-Alonso;Paulo Gonçalves;Edison Pignaton de Freitas;Alberto Olivares Alarcos;Joanna Isabelle Olszewska;Edson Prestes;Craig Schlenoff;S. Veera Ragavan;Signe Redfield;Bruce Spencer;Howard Li;
Appeared in: IEEE Robotics & Automation Magazine
Publication date: Mar 2017, volume: 24, issue:1, pages: 8 - 11
Publisher: IEEE
 
» A Superconducting Magnetic Energy Storage-Emulator/Battery Supported Dynamic Voltage Restorer
Abstract:
This study examines the use of superconducting magnetic and battery hybrid energy storage to compensate grid voltage fluctuations. The superconducting magnetic energy storage system (SMES) has been emulated by a high-current inductor to investigate a system employing both SMES and battery energy storage experimentally. The design of the laboratory prototype is described in detail, which consists of a series-connected three phase voltage source inverter used to regulate ac voltage, and two bidirectional dc/dc converters used to control energy storage system charge and discharge. “DC bus level signaling” and “voltage droop control” have been used to automatically control power from the magnetic energy storage system during short-duration, high-power voltage sags, while the battery is used to provide power during longer term, low-power undervoltages. Energy storage system hybridization is shown to be advantageous by reducing battery peak power demand compared with a battery-only system, and by improving long-term voltage support capability compared with an SMES-only system. Consequently, the SMES/battery hybrid dynamic voltage restorer can support both short-term high-power voltage sags and long-term undervoltages with significantly reduced superconducting material cost compared with an SMES-based system.
Autors: Anthony M. Gee;Francis Robinson;Weijia Yuan;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Mar 2017, volume: 32, issue:1, pages: 55 - 64
Publisher: IEEE
 
» A Survey of Diet Monitoring Technology
Abstract:
This article surveys techniques for evaluating eating habits for wellness applications, emphasizing sensor-based approaches such as audio signal processing, inertial sensing, image processing, and gesture recognition. The focus is on noninvasive technologies that could be developed into real-time wearable devices, rather than techniques whose use is limited to laboratory settings. The authors present the results of an online survey in which respondents rate and describe their impressions of various approaches.
Autors: Haik Kalantarian;Nabil Alshurafa;Majid Sarrafzadeh;
Appeared in: IEEE Pervasive Computing
Publication date: Mar 2017, volume: 16, issue:1, pages: 57 - 65
Publisher: IEEE
 
» A Synthesis-Free Directional Modulation Transmitter Using Retrodirective Array
Abstract:
By modification of the classical retrodirective array architecture, a directional modulation (DM) transmitter can be realized without the need for synthesis. Importantly, through analytical analysis and exemplar simulations, it is proved that, besides the conventional DM application scenario, i.e., secure transmission to one legitimate receiver located along one spatial direction in free space, the proposed synthesis-free DM transmitter should also perform well for systems where there are more than one legitimate receiver positioned along different directions in free space, and where one or more legitimate receivers exist in a multipath environment. None of these have ever been achieved before using synthesis-free DM arrangements.
Autors: Yuan Ding;Vincent Fusco;
Appeared in: IEEE Journal of Selected Topics in Signal Processing
Publication date: Mar 2017, volume: 11, issue:2, pages: 428 - 441
Publisher: IEEE
 
» A Systematic Design Method and Verification of a Zero Current Ripple Interface for PV-to-Battery Applications
Abstract:
A systematic method of designing a zero terminal current ripple integrated magnetic Ćuk converter for photovoltaic (PV)-to-battery applications is presented in this paper. The four-winding-coupled inductor design consists of two inductors and a two-winding transformer coupled on a common EE-core. The core design uses a simplified flux-reluctance model to arrive at the area product formulation for this kind of a four-winding structure. The zero-ripple condition in the terminal currents is achieved by controlling the coupling coefficients by means of air-gap reluctances in the core. Unlike the earlier designs for this converter, it provides a completely analytical approach to design this converter for a range of duty ratio. The validity of the proposed method is confirmed using finite element analyses (both two dimensional and three dimensional), thermal validation, and circuit simulations in PSpice. The zero-ripple condition is verified experimentally.
Autors: Suvankar Biswas;Ned Mohan;William P. Robbins;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Mar 2017, volume: 53, issue:2, pages: 1177 - 1187
Publisher: IEEE
 
» A Technique Based on Naming Patterns for Finding Candidates to Components from Source Code
Abstract:
Component identification is relevant in maintenance activities but can be hard in scenarios where the volume of source code is high and there is no architecture documentation. This work presents a technique for finding concepts as candidates of architectural components. The technique is based in the frequency of terms that follows naming patterns that are proposed in this work. Projects from Eclipse and Apache, were used for evaluating the technique. The results show terms which match with some popular component types and domain concepts of the software in treatment. The technique has used source code without any architectural documentation showing that could be applied in emergent architectures.
Autors: Paul Mendoza;Abraham Davila;
Appeared in: IEEE Latin America Transactions
Publication date: Mar 2017, volume: 15, issue:3, pages: 482 - 487
Publisher: IEEE
 
» A Three-Phase Digital Current Controller With Improved Performance Indices
Abstract:
Performance of conventional digital current controllers is constrained by transport delays within the feedback acquisition chain, as well as by delays inherent to the pulse width modulation. In this paper, we introduce a novel current controller which provides a very high closed-loop bandwidth, improves the robustness and disturbance rejection, and eliminates the noise and sampling errors in the feedback path. In order to achieve these goals, we suppress the transport delays by introducing an improved execution schedule of the control interrupt and by inserting a cascaded multiplier of differential character. With the novel gain setting rule, the closed-loop bandwidth reaches 17% of the sampling frequency, disturbance rejection capability is doubled, the step response has a negligible overshoot, and the robustness is characterized by the vector margin of 0.65. Experimental verification is performed using an experimental setup with a three-phase inverter, digital controller, and a permanent magnet synchronous motor.
Autors: Slobodan N. Vukosavić;Ljiljana S. Perić;Emil Levi;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Mar 2017, volume: 32, issue:1, pages: 184 - 193
Publisher: IEEE
 
» A Transformer-Based $V$ -Band SPDT Switch
Abstract:
This letter presents a novel transformer-based 58–85 GHz single-pole double-throw (SPDT) switch structure, verified in a 65-nm CMOS process. A four-way transformer-based combiner implements the input impedance transformation resulting in significant chip area reduction to 0.015 mm2, which is smaller than one tenth of the conventional SPDT switch based on /4 transmission lines. The designed SPDT switch achieves 1.8-dB insertion loss, 22–30 dB isolation and >10 dB return loss over 58–85 GHz band with input-referred P1dB compression point of 10 dBm at 66 GHz. The good performance validates the application of the newly invented structure for the challenging millimeter-wave frequency switches in integrated systems.
Autors: Ran Shu;Qun Jane Gu;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Mar 2017, volume: 27, issue:3, pages: 278 - 280
Publisher: IEEE
 
» A Trust Cloud Model for Underwater Wireless Sensor Networks
Abstract:
Nowadays, the study of underwater WSNs (UWSNs) has become a hot topic. However, UWSNs have not been fully utilized in the complex underwater environment, since there are some difficulties in controlling mobile sensor nodes and underwater environment conditions. In addition, how to ensure the security of UWSNs and the safety of underwater mobile sensor nodes has not been solved well. In this article, we study the problem of trust establishment between nodes in UWSNs. We first give a detailed overview of existing trust management mechanisms. Since UWSNs possess specific characteristics, it is noted that those existing mechanisms are not applicable for UWSNs. We then introduce a trust cloud model that is suitable for trust management in UWSNs.
Autors: Jinfang Jiang;Guangjie Han;Chunsheng Zhu;Sammy Chan;Joel J. P. C. Rodrigues;
Appeared in: IEEE Communications Magazine
Publication date: Mar 2017, volume: 55, issue:3, pages: 110 - 116
Publisher: IEEE
 
» A TV Receiver Front-End With Linearized LNA and Current-Summing Harmonic Rejection Mixer
Abstract:
A low-noise and highly linear wideband receiver front-end composed of the linearized low noise amplifier and current-summing harmonic rejection mixer is implemented in a 0.18- CMOS process for TV tuner applications. It shows a measured voltage gain of more than 34.5 dB, a noise figure of less than 3.5 dB, and a third-order input-referred intercept point (IIP3) of more than −20 dBm in the frequency range from 44 to 880 MHz. The baseband coefficient scaling and summation based on the current mirror ensure a third- and fifth-harmonic rejection ratio of over 45 dBc in measurement with high linearity performance. The power consumption of the proposed TV receiver front-end is 16.2 mW at a 1.8-V supply voltage.
Autors: Donggu Im;Ockgoo Lee;Ilku Nam;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Mar 2017, volume: 64, issue:3, pages: 269 - 273
Publisher: IEEE
 
» A Two-Level Approach to AC Optimal Transmission Switching With an Accelerating Technique
Abstract:
DC-based optimal transmission switching (OTS) cannot consider ac feasibility, which hinders the exploitation of the benefits of OTS in power system operations. This paper proposes a new OTS approach that considers ac feasibility. The approach uses a two-level iterative framework in which a mixed integer second-order cone programming OTS model provides candidate solutions at the upper level, while the ac feasibility check is conducted at the lower level. An accelerating technique is developed to significantly improve the computational efficiency while maintaining accuracy. Case studies using the IEEE 57-bus system, the IEEE 118-bus system and a real-world large system demonstrate the efficacy of the proposed approach.
Autors: Yang Bai;Haiwang Zhong;Qing Xia;Chongqing Kang;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 1616 - 1625
Publisher: IEEE
 
» A Unified Automated Parametric Modeling Algorithm Using Knowledge-Based Neural Network and ${l}_{1}$ Optimization
Abstract:
Knowledge-based neural network modeling techniques using space-mapping concept have been demonstrated in the existing literature as efficient methods to overcome the accuracy limitations of empirical/equivalent circuit models when matching new electromagnetic data. For different modeling problems, the mapping structures can be different. In this paper, we propose a unified automated model generation algorithm that uses optimization to automatically determine the type and the topology of the mapping structure in a knowledge-based neural network model. By encompassing various types of mappings of the knowledge-based neural network model in the existing literature, we present a new unified model structure and derive new sensitivity formulas for the training of the unified model. The proposed formulation of modeling can force some weights of the mapping neural networks to zeros while leaving other weights as nonzeros. We utilize this feature to allow optimization to automatically determine which mapping is necessary and which mapping is unnecessary. Using the proposed optimization method, the mapping structure can be determined to address different needs of different modeling problems. The structure of the final knowledge-based model can be flexible combinations of some or all of linear mapping, nonlinear mapping, input mapping, frequency mapping, and output mapping. In this way, the proposed algorithm is more systematic and can further speed up the knowledge-based modeling process than existing knowledge-based modeling algorithms. The proposed method is il- ustrated by three microwave filter modeling examples.
Autors: Weicong Na;Feng Feng;Chao Zhang;Qi-Jun Zhang;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Mar 2017, volume: 65, issue:3, pages: 729 - 745
Publisher: IEEE
 
» A Unified Design Flow to Automatically Generate On-Chip Monitors During High-Level Synthesis of Hardware Accelerators
Abstract:
Security and safety are more and more important in embedded system design. A key issue, hence lies in the ability of systems to respond safely when errors occur at runtime, to prevent unacceptable behaviors that can lead to failures or sensitive data leakage. In this paper, we propose a design approach that automatically generates on-chip monitors (OCMs) during high-level synthesis (HLS) of hardware accelerators (HWaccs). OCM checks at runtime the input/output timing behavior, the control flow execution and algorithmic properties (via American National Standards Institute C assertions) of the monitored HWacc. OCM is implemented separately from the HWacc and an original technique is introduced for their synchronization. Two synthesis options are proposed to tradeoff between performance and area. Experiment results show that error detection on the control flow is better compared to the existing approaches while the cost of assertions is reduced by 17.48% on average. The impact on execution time (i.e., latency of the HWacc) is decreased by at no area penalty and up to with less than 10% extra-area. The clock period overhead is at worst less than 5% and the overhead on the synthesis time of the HWacc to generate OCMs is 7.44% on average.
Autors: Mohamed Ben Hammouda;Philippe Coussy;Loïc Lagadec;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Mar 2017, volume: 36, issue:3, pages: 384 - 397
Publisher: IEEE
 
» A Unified Urban Mobile Cloud Computing Offloading Mechanism for Smart Cities
Abstract:
The increasing urbanization level of the world population has driven the development of a smart city geographic system, conceived as a fully connected wide area characterized by the presence of a multitude of smart devices, sensors, and processing nodes aimed at distributing intelligence into the city. At the same time, the pervasiveness of wireless technologies has led to the presence of heterogeneous networks, operating simultaneously in the same city area. One of the main challenges in this context is to provide sustainable solutions able to jointly optimize the data transfer, exploiting heterogeneous networks, and the data processing, exploiting heterogeneous devices, for managing smart city applications for citizens' communities. In this article, the UMCC framework is developed, introducing a mobile cloud computing model describing the flows of data and operations taking place in the smart city. In particular, we focus on the proposal of a unified offloading mechanism where communication and computing resources are jointly managed, allowing load balancing among the different entities in the environment, delegating both communication and computation tasks in order to satisfy the smart city application requirements. This allows us to cope with the limited battery power and computation capacity of smart mobile devices and plays a key role in a smart environment where wireless communication is of utmost relevance, particularly in the mobility and traffic control domains.
Autors: Daniela Mazza;Daniele Tarchi;Giovanni E. Corazza;
Appeared in: IEEE Communications Magazine
Publication date: Mar 2017, volume: 55, issue:3, pages: 30 - 37
Publisher: IEEE
 
» A Wake-Up Call [President's Column]
Abstract:
Presents the President's message for this issue of the publication.
Autors: Dylan Williams;
Appeared in: IEEE Microwave Magazine
Publication date: Mar 2017, volume: 18, issue:2, pages: 10 - 12
Publisher: IEEE
 
» A Way-Filtering-Based Dynamic Logical–Associative Cache Architecture for Low-Energy Consumption
Abstract:
Last-level caches (LLCs) help improve performance but suffer from energy overhead because of their large sizes. An effective solution to this problem is to selectively power down several cache ways, which, however, reduces cache associativity and performance and thus limits its effectiveness in reducing energy consumption. To overcome this limitation, we propose a new cache architecture that can logically increase cache associativity of way-powered-down LLCs. Our proposed scheme is designed to be dynamic in activating an appropriate number of cache ways in order to eliminate the need for static profiling to determine an energy-optimized cache configuration. The experimental results show that our proposed dynamic scheme reduces the energy consumption of LLCs by 34% and 40% on single- and dual-core systems, respectively, compared with the best performing conventional static cache configuration. The overall system energy consumption including CPU, L2 cache, and DRAM is reduced by 9.2% on quad-core systems.
Autors: Jungwoo Park;Jongmin Lee;Soontae Kim;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Mar 2017, volume: 25, issue:3, pages: 793 - 805
Publisher: IEEE
 
» A Wide Dynamic Range CMOS Laser Radar Receiver With a Time-Domain Walk Error Compensation Scheme
Abstract:
This integrated receiver channel designed for a pulsed time-of-flight (TOF) laser rangefinder consists of a fully differential transimpedance amplifier channel and a timing discriminator. The amplitude-dependent timing walk error is compensated by measuring the width and rise time of the received pulse echo and using this information for calibration. The measured bandwidth, transimpedance and minimum detectable signal (SNR ~10) of the receiver channel are 230 MHz, and respectively. The single-shot precision of the receiver is ~3 cm at an SNR of 13 and the measurement accuracy is ±4 mm with compensation within a dynamic range of ~1:100 000. The receiver circuit was realized in a CMOS process and has a power consumption of 150 mW. The functionality of the receiver channel was verified over a temperature range of -20 °C to +50 °C.
Autors: S. Kurtti;J. Nissinen;J. Kostamovaara;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Mar 2017, volume: 64, issue:3, pages: 550 - 561
Publisher: IEEE
 
» A Wide-Angle Scanning Planar Phased Array with Pattern Reconfigurable Magnetic Current Element
Abstract:
A wide-angle scanning planar phased array with magnetic current elements is proposed. A pattern reconfigurable technique is used to design the element that enhances scanning gain and decreases the sidelobe level throughout the entire scanning range. The array is comprised of eight elements in a arrangement with uniform spacing. The proposed phased array operates at 5.8 GHz and can scan with 3 dB beamwidth the entire upper ground elevation plane from −90° to +90° enabled by a two-step pattern reconfigurability mechanism consisting of: 1) coarse-angle scanning and 2) fine-angle scanning. Significant outcomes also include the reduced sidelobe level (less than 7.8 dB) and the particularly small fluctuation (±0.75 dB) of the gain during scanning over a scanning range of 150° (from −75° to +75° in the elevation plane). With the absence of any structure above the ground level, the high efficiency, and the coverage of the entire upper half-space, this proposed antenna array is very attractive for a variety of phased array applications, particularly those that require a flush-mounted structure.
Autors: Xiao Ding;You-Feng Cheng;Wei Shao;Hua Li;Bing-Zhong Wang;Dimitris E. Anagnostou;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Mar 2017, volume: 65, issue:3, pages: 1434 - 1439
Publisher: IEEE
 
» A Wideband Millimeter-Wave Circularly Polarized Antenna With 3-D Printed Polarizer
Abstract:
This paper presents a wideband circularly polarized millimeter-wave (mmw) antenna design. We introduce a novel 3-D-printed polarizer, which consists of several air and dielectric slabs to transform the polarization of the antenna radiation from linear to circular. The proposed polarizer is placed above a radiating aperture operating at the center frequency of 60 GHz. An electric field, , radiated from the aperture generates two components of electric fields, and . After passing through the polarizer, both and fields can be degenerated with an orthogonal phase difference which results in having a wide axial ratio bandwidth. The phase difference between and is determined by the incident angle , of the polarization of the electric field to the polarizer as well as the thickness, , of the dielectric slabs. With the help of the thickness of the polarizer, the directivity of the radiation pattern is increased so as to devote high-gain and wideband characteristics to the antenna. To verify our concept, an intensive parametric study and an experiment were carried out. Three antenna sources, including dipole, patch, and aperture antennas, were investigated with the proposed 3-D-printed pola- izer. All measured results agree with the theoretical analysis. The proposed antenna with the polarizer achieves a wide impedance bandwidth of 50% from 45 to 75 GHz for the reflection coefficient less than or equal −10 dB, and yields an overlapped axial ratio bandwidth of 30% from 49 to 67 GHz for the axial ratio ≤ 3 dB. The maximum gain of the antenna reaches to 15 dBic. The proposed methodology of this design can apply to applications related to mmw wireless communication systems. The ultimate goal of this paper is to develop a wideband, high-gain, and low-cost antenna for the mmw frequency band.
Autors: Kai Xu Wang;Hang Wong;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Mar 2017, volume: 65, issue:3, pages: 1038 - 1046
Publisher: IEEE
 
» Abnormal Dual Channel Formation Induced by Hydrogen Diffusion From SiNx Interlayer Dielectric in Top Gate a-InGaZnO Transistors
Abstract:
This letter investigates effects of different channel dimensions in top-gate a-InGaZnO4 thin-film transistors with SiNx interlayer dielectric. In narrow channel devices, hydrogen atoms in the SiNx layer diffuse into the entire active layer, inducing a single channel. However, in wider channel devices, the diffusion distance for hydrogen atoms is insufficient to affect the whole channel, instead inducing a double channel. In addition, under hot carrier stress, narrow and wide channels exhibit different degradation behaviors, with simulations showing a strong electrical field at IGZO near the drain terminal of the main channel, which is unaffected by hydrogen.
Autors: Guan-Fu Chen;Ting-Chang Chang;Hua-Mao Chen;Bo-Wei Chen;Hong-Chih Chen;Cheng-Ya Li;Ya-Hsiang Tai;Yu-Ju Hung;Kuo-Jui Chang;Kai-Chung Cheng;Chen-Shuo Huang;Kuo-Kuang Chen;Hsueh-Hsing Lu;Yu-Hsin Lin;
Appeared in: IEEE Electron Device Letters
Publication date: Mar 2017, volume: 38, issue:3, pages: 334 - 337
Publisher: IEEE
 
» Accelerated Evaluation of Automated Vehicles Safety in Lane-Change Scenarios Based on Importance Sampling Techniques
Abstract:
Automated vehicles (AVs) must be thoroughly evaluated before their release and deployment. A widely used evaluation approach is the Naturalistic-Field Operational Test (N-FOT), which tests prototype vehicles directly on the public roads. Due to the low exposure to safety-critical scenarios, N-FOTs are time consuming and expensive to conduct. In this paper, we propose an accelerated evaluation approach for AVs. The results can be used to generate motions of the other primary vehicles to accelerate the verification of AVs in simulations and controlled experiments. Frontal collision due to unsafe cut-ins is the target crash type of this paper. Human-controlled vehicles making unsafe lane changes are modeled as the primary disturbance to AVs based on data collected by the University of Michigan Safety Pilot Model Deployment Program. The cut-in scenarios are generated based on skewed statistics of collected human driver behaviors, which generate risky testing scenarios while preserving the statistical information so that the safety benefits of AVs in nonaccelerated cases can be accurately estimated. The cross-entropy method is used to recursively search for the optimal skewing parameters. The frequencies of the occurrences of conflicts, crashes, and injuries are estimated for a modeled AV, and the achieved accelerated rate is around 2000 to 20 000. In other words, in the accelerated simulations, driving for 1000 miles will expose the AV with challenging scenarios that will take about 2 to 20 million miles of real-world driving to encounter. This technique thus has the potential to greatly reduce the development and validation time for AVs.
Autors: Ding Zhao;Henry Lam;Huei Peng;Shan Bao;David J. LeBlanc;Kazutoshi Nobukawa;Christopher S. Pan;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Mar 2017, volume: 18, issue:3, pages: 595 - 607
Publisher: IEEE
 
» Accelerating Vanishing Point-Based Line Sampling Scheme for Real-Time People Localization
Abstract:
In advanced video surveillance systems, people localization is usually a part of the complete system and should be accomplished in a short time so as to reserve sufficient processing time for subsequent high-level analysis, such as abnormal event/behavior detection and intruder detection. Hence, in addition to localization accuracy, computational efficiency is of critical importance as well. In this paper, we adopt a vanishing point-based line sampling scheme and propose a fast multicamera people localization approach capable of locating a crowd of dense people and estimating their heights in a fairly short time with high accuracy. For each camera view, sample lines, originated from a vanishing point, of foreground objects are projected onto the ground plane. Then, people locations are estimated by detecting the ground regions containing a high density of the projected lines. Enhanced from some previous works, the proposed approach does not require processing steps of high computation cost, such as projecting all foreground pixels of all views to multiple reference planes or computing pairwise intersections of projected sample lines at different heights. In addition, some novel acceleration modules, such as torso validation and physical rule-based filtering, are developed to further reduce the computation time of people localization. The experiments on real surveillance scenes validate that the proposed approach achieves significant speedup (up to 186%) over state-of-the-art techniques while still ensure a comparably high localization accuracy, even for crowded scenes with serious occlusions.
Autors: Chin-Wei Liu;Hua-Tsung Chen;Kuo-Hua Lo;Chih-Jung Wang;Jen-Hui Chuang;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Mar 2017, volume: 27, issue:3, pages: 409 - 420
Publisher: IEEE
 
» Accessibility in ATSC 3.0 [November (2016)]
Abstract:
Many people are either hearing or visually impaired or may be completely deaf or blind. Having access to television news, weather, sports, and entertainment requires unique accessibility services. In television broadcast videos can be closed captioned so deaf and hard-of-hearing users can understand the video while Video Description Service can accommodate better understanding of on screen action for the blind or visually impaired. As an emerging platform, ATSC 3.0, can provide an opportunity to improve on these services and offer new ones.
Autors: Chris L. Homer;Michael A Dolan;
Appeared in: IEEE Transactions on Broadcasting
Publication date: Mar 2017, volume: 63, issue:1, pages: 237 - 239
Publisher: IEEE
 
» Accessibility of Nonlinear Time-Delay Systems
Abstract:
A full characterization of accessibility is provided for nonlinear time-delay systems. It generalizes the rank condition which is known for weak controllability of linear time-delay systems, as well as the celebrated geometric approach for delay-free nonlinear systems and the characterization of their accessibility. Besides, fundamental results are derived on integrability and basis completion which are of major importance for a number of general control problems for nonlinear time-delay systems. They are shown to impact preconceived ideas about canonical forms for nonlinear time-delay systems.
Autors: Claudia Califano;Claude H. Moog;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Mar 2017, volume: 62, issue:3, pages: 1254 - 1268
Publisher: IEEE
 
» Accurate and Easy-to-Obtain Iron Loss Model for Electric Machine Design
Abstract:
Iron loss modeling is crucial for electric machine design. However, current models feature severe drawbacks. They are 1) very complex, and thus, can hardly be applied, 2) require very high effort for measuring and computation, and/or 3) are not very accurate. In this paper, a new modeling technique is introduced for calculating the instantaneous power loss in ferromagnetic materials without taking the magnetization history into account. A standard measurement setup and specimen shape is used. The considered approach comprises the required measurements, the nonlinear loss modeling by itself, and an extensive verification for different flux density waveforms and frequencies. In addition, a detailed qualitative comparison to well-known iron loss models is given. The presented technique gives very accurate results, while obtaining the model is comparably easy. Moreover, as the calculation of the instantaneous losses is not based on the previous magnetization state of the material, a modeling error for a particular instant of time has no impact on the subsequently calculated characteristics. In the future, this model should ensure a more accurate iron loss calculation for electric machine designs.
Autors: Gerd Bramerdorfer;Dietmar Andessner;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2530 - 2537
Publisher: IEEE
 
» Accurate Measurement of Small Execution Times—Getting Around Measurement Errors
Abstract:
Engineers and researchers often require accurate measurements of small execution times or duration of events in a program. Errors in the measurement facility can introduce important challenges, especially when measuring small intervals. Mitigating approaches commonly used exhibit several issues; in particular, they only reduce the effect of the error, and never eliminate it. In this letter, we propose a technique to effectively eliminate measurement errors and obtain a robust statistical estimate of execution time or duration of events in a program. The technique is simple to implement, yet it entirely eliminates the systematic (nonrandom) component of the measurement error, as opposed to simply reduce it. Experimental results confirm the effectiveness of the proposed method.
Autors: Carlos Moreno;Sebastian Fischmeister;
Appeared in: IEEE Embedded Systems Letters
Publication date: Mar 2017, volume: 9, issue:1, pages: 17 - 20
Publisher: IEEE
 
» Achievable Degrees of Freedom of the -User SISO Interference Channel With Blind Interference Alignment Using Staggered Antenna Switching
Abstract:
In this paper, we characterize the achievable (linear) degrees of freedom (DoFs) of the -user single-input single-output (SISO) interference channel with blind interference alignment (BIA) using staggered antenna switching. In this scheme, each transmitter is equipped with one conventional antenna, and each receiver is equipped with one reconfigurable (multimode) antenna. Assuming that the channel is known to the receivers only, we show that by using linear BIA with staggered antenna switching at the receiver, a sum DoF of is achievable. This result implies that in using BIA, we can double the DoF achieved by orthogonal multiple-access schemes for a large number of users. Moreover, we propose a systematic algorithm to generate the transmit beamforming vectors and the reconfigurable antenna switching patterns, showing that it can achieve the sum DoF for any . Finally, we apply this algorithm to the four-user SISO interference channel and demonstrate that sum DoF is indeed achievable.
Autors: Ahmed M. Alaa;Mahmoud H. Ismail;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2825 - 2829
Publisher: IEEE
 
» Achievable Degrees of Freedom of the -User SISO Interference Channel With Blind Interference Alignment Using Staggered Antenna Switching
Abstract:
In this paper, we characterize the achievable (linear) degrees of freedom (DoFs) of the -user single-input single-output (SISO) interference channel with blind interference alignment (BIA) using staggered antenna switching. In this scheme, each transmitter is equipped with one conventional antenna, and each receiver is equipped with one reconfigurable (multimode) antenna. Assuming that the channel is known to the receivers only, we show that by using linear BIA with staggered antenna switching at the receiver, a sum DoF of is achievable. This result implies that in using BIA, we can double the DoF achieved by orthogonal multiple-access schemes for a large number of users. Moreover, we propose a systematic algorithm to generate the transmit beamforming vectors and the reconfigurable antenna switching patterns, showing that it can achieve the sum DoF for any . Finally, we apply this algorithm to the four-user SISO interference channel and demonstrate that sum DoF is indeed achievable.
Autors: Ahmed M. Alaa;Mahmoud H. Ismail;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2825 - 2829
Publisher: IEEE
 
» Achieving a 100% Renewable Grid: Operating Electric Power Systems with Extremely High Levels of Variable Renewable Energy
Abstract:
What does it mean to achieve a 100% renewable grid? Several countries already meet or come close to achieving this goal. Iceland, for example, supplies 100% of its electricity needs with either geothermal or hydropower. Other countries that have electric grids with high fractions of renewables based on hydropower include Norway (97%), Costa Rica (93%), Brazil (76%), and Canada (62%). Hydropower plants have been used for decades to create a relatively inexpensive, renewable form of energy, but these systems are limited by natural rainfall and geographic topology. Around the world, most good sites for large hydropower resources have already been developed. So how do other areas achieve 100% renewable grids? Variable renewable energy (VRE), such as wind and solar photovoltaic (PV) systems, will be a major contributor, and with the reduction in costs for these technologies during the last five years, large-scale deployments are happening around the world.
Autors: Benjamin Kroposki;Brian Johnson;Yingchen Zhang;Vahan Gevorgian;Paul Denholm;Bri-Mathias Hodge;Bryan Hannegan;
Appeared in: IEEE Power and Energy Magazine
Publication date: Mar 2017, volume: 15, issue:2, pages: 61 - 73
Publisher: IEEE
 
» Achieving Lower Insertion Loss and Higher Sensitivity in a SAW Biosensor via Optimization of Waveguide and Microcavity Structures
Abstract:
Achieving low power consumption and high sensitivity is a major obstacle in realizing the potential of surface acoustic wave (SAW) devices in portable sensing applications. In this paper, we demonstrate that an optimal combination of a microcavity structure filled with a low acoustic impedance material in the delay path combined with a suitable wave guide lowers power consumption substantially and improves sensitivity. 3-D finite-element method (FEM) simulations were employed to systematically evaluate the effect of various filling and waveguide materials for ~100 MHz devices in ST quartz. Based on the simulated device designs, trends in device performance, and ease of fabrication, SAW sensors were fabricated in ST quartz with tantalum filling of the microcavity array along with an optimal SiO2 wave guide to achieve improvements on the order of 5 dB in insertion loss and nearly ten times the sensitivity compared with an SAW device without these modifications. This paper allows for the possibility of designing and realizing robust SAW sensors for detection at concentration levels of relevance to clinical diagnosis, i.e., sub-ng to ng/mL levels.
Autors: Shuangming Li;Subramanian K. R. S. Sankaranarayanan;Chunhai Fan;Yan Su;Venkat R. Bhethanabotla;
Appeared in: IEEE Sensors Journal
Publication date: Mar 2017, volume: 17, issue:6, pages: 1608 - 1616
Publisher: IEEE
 
» Achieving Ultra-Low Latency in 5G Millimeter Wave Cellular Networks
Abstract:
The IMT 2020 requirements of 20 Gb/s peak data rate and 1 ms latency present significant engineering challenges for the design of 5G cellular systems. Systems that make use of the mmWave bands above 10 GHz ---where large regions of spectrum are available --- are a promising 5G candidate that may be able to rise to the occasion. However, although the mmWave bands can support massive peak data rates, delivering these data rates for end-to-end services while maintaining reliability and ultra-low-latency performance to support emerging applications and use cases will require rethinking all layers of the protocol stack. This article surveys some of the challenges and possible solutions for delivering end-to-end, reliable, ultra-low-latency services in mmWave cellular systems in terms of the MAC layer, congestion control, and core network architecture.
Autors: Russell Ford;Menglei Zhang;Marco Mezzavilla;Sourjya Dutta;Sundeep Rangan;Michele Zorzi;
Appeared in: IEEE Communications Magazine
Publication date: Mar 2017, volume: 55, issue:3, pages: 196 - 203
Publisher: IEEE
 
» ACO-Based Thermal-Aware Thread-to-Core Mapping for Dark-Silicon-Constrained CMPs
Abstract:
The limitation on thermal budget in chip multiprocessor (CMP) results in a fraction of inactive silicon regions called dark silicon, which significantly impacts the system performance. In this paper, we propose a thread-to-core mapping method for dark-silicon-constrained CMPs to address their thermal issue. We first propose a thermal prediction model to forecast CMP temperature after the CMP executes a forthcoming application. Then, we develop an ant colony optimization-based algorithm to conduct the thread-to-core mapping process, such that the CMP peak temperature is minimized and, consequently, the probability of triggering CMP dynamic thermal management is decreased. Finally, we evaluate our method and compare it with the baseline (a standard Linux scheduler) and other existing methods (NoC-Sprinting, DaSiM mapping, and TP mapping). The simulation results show that our method gains good thermal profile and computational performance, and performs well with chip scaling. Specifically, it eliminates all thermal emergency time, outperforming all other methods, and gains million instructions per second improvement up to 12.9% against the baseline.
Autors: Jian Wang;Zhe Chen;Jinhong Guo;Yubai Li;Zhonghai Lu;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 930 - 937
Publisher: IEEE
 
» Adaptation of Biochemical Protocols to Handle Technology-Change for Digital Microfluidics
Abstract:
Advances in digital microfluidic (DMF) technologies offer a promising platform for a variety of biochemical applications, ranging from massively parallel DNA analysis and computational drug discovery to toxicity monitoring and medical diagnosis. In this paper, we address the migration problem that arises when the technology undergoes a change in the context of DMFs. Given a biochemical reaction synthesized for actuation on a given DMF architecture, we discuss how the same biochemical reaction can be ported seamlessly to an enhanced architecture, with possible modifications to the architectural parameters (e.g., clock frequency, mixer size, and mixing time) or geometric changes (e.g., change in reservoir locations or mixer positions, inclusion of new sensors or other physical resources). Complete resynthesis of the protocol for the new architecture may often become either inefficient or even infeasible due to scalability, proprietary, security, or cost issues. We propose an adaptation method for handling such technology-changes by modifying the existing actuation sequence through an incremental procedure. The foundation of our method lies in symbolic encoding and satisfiability-solvers, enriched with pertinent graph-theoretic and geometric techniques. This enables us to generate functionally correct solutions for the new target architecture without necessitating a complete resynthesis step, thereby enabling the utilization of these chips by users in biology who are not familiar with the on-chip synthesis tool-flow. We highlight the benefits of the proposed approach through extensive simulations on assay benchmarks.
Autors: Sukanta Bhattacharjee;Sharbatanu Chatterjee;Ansuman Banerjee;Tsung-Yi Ho;Krishnendu Chakrabarty;Bhargab B. Bhattacharya;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Mar 2017, volume: 36, issue:3, pages: 370 - 383
Publisher: IEEE
 
» Adapting to Change: Hawai'i's Response to Alternative Energy Sources [In My View]
Abstract:
Discusses how the stat of Hawaii is preparing to deploy alternative energy resources into its power grid system.
Autors: Colton Ching;
Appeared in: IEEE Power and Energy Magazine
Publication date: Mar 2017, volume: 15, issue:2, pages: 93 - 96
Publisher: IEEE
 
» Adaptive Compressed Sensing for Support Recovery of Structured Sparse Sets
Abstract:
This paper investigates the problem of recovering the support of structured signals via adaptive compressive sensing. We examine several classes of structured support sets, and characterize the fundamental limits of accurately recovering such sets through compressive measurements, while simultaneously providing adaptive support recovery protocols that perform near optimally for these classes. We show that by adaptively designing the sensing matrix, we can attain significant performance gains over non-adaptive protocols. These gains arise from the fact that adaptive sensing can: 1) better mitigate the effects of noise and 2) better capitalize on the structure of the support sets.
Autors: Rui M. Castro;Ervin Tánczos;
Appeared in: IEEE Transactions on Information Theory
Publication date: Mar 2017, volume: 63, issue:3, pages: 1535 - 1554
Publisher: IEEE
 
» Adaptive DC Stabilizer With Reduced DC Fault Current for Active Distribution Power System Application
Abstract:
This paper takes a systematic view on the control and protection of medium power DC networks in an active distribution power system considering fault current limiting, system control, and converter design. Reduced terminal capacitance and extra DC impedance are used to limit DC fault current and reduce the required converter current rating for medium power DC networks. An adaptive DC power stabilizer is proposed to alleviate possible system instability brought by the fault current limiting settings in the presence of constant power load. The effect of the current limiting method and the proposed stabilizer on DC fault current and stability enhancement are validated by simulation studies using a simple two-converter DC network and a multiterminal DC network in an active distribution power system.
Autors: Dong Chen;Lie Xu;James Yu;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 1430 - 1439
Publisher: IEEE
 
» Adaptive Estimation of Active Contour Parameters Using Convolutional Neural Networks and Texture Analysis
Abstract:
In this paper, we propose a generalization of the level set segmentation approach by supplying a novel method for adaptive estimation of active contour parameters. The presented segmentation method is fully automatic once the lesion has been detected. First, the location of the level set contour relative to the lesion is estimated using a convolutional neural network (CNN). The CNN has two convolutional layers for feature extraction, which lead into dense layers for classification. Second, the output CNN probabilities are then used to adaptively calculate the parameters of the active contour functional during the segmentation process. Finally, the adaptive window size surrounding each contour point is re-estimated by an iterative process that considers lesion size and spatial texture. We demonstrate the capabilities of our method on a dataset of 164 MRI and 112 CT images of liver lesions that includes low contrast and heterogeneous lesions as well as noisy images. To illustrate the strength of our method, we evaluated it against state of the art CNN-based and active contour techniques. For all cases, our method, as assessed by Dice similarity coefficients, performed significantly better than currently available methods. An average Dice improvement of 0.27 was found across the entire dataset over all comparisons. We also analyzed two challenging subsets of lesions and obtained a significant Dice improvement of 0.24 with our method (p <0.001, Wilcoxon).
Autors: Assaf Hoogi;Arjun Subramaniam;Rishi Veerapaneni;Daniel L. Rubin;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Mar 2017, volume: 36, issue:3, pages: 781 - 791
Publisher: IEEE
 
» Adaptive Neural Network Based Variable Stiffness Control of Uncertain Robotic Systems Using Disturbance Observer
Abstract:
The variable stiffness actuator (VSA) has been equipped on many new generations of robots because of its superior performance in terms of safety, robustness, and flexibility. However, the control of robots with joints driven by VSAs is challenging due to the inherited highly nonlinear dynamics. In this paper, a novel disturbance observer based adaptive neural network control is proposed for robotic systems with variable stiffness joints and subject to model uncertainties. By utilizing a high-dimensional integral Lyapunov function, adaptive neural network control is designed to compensate for the model uncertainties, and a disturbance observer is integrated to compensate for the nonlinear VSA dynamics, as well as the neural network approximation errors and external disturbance. The semiglobally uniformly ultimately boundness of the closed-loop control system has been theoretically established. Simulation and extensive experimental studies have also been presented to verify the effectiveness of the proposed approach.
Autors: Longbin Zhang;Zhijun Li;Chenguang Yang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2236 - 2245
Publisher: IEEE
 
» Adaptive Secure Transmission for Physical Layer Security in Cooperative Wireless Networks
Abstract:
We investigate the physical layer security in cooperative wireless networks where a source (Alice) transmits a confidential message to a destination (Bob) with the help of a cooperative node (Charlie), in the presence of an eavesdropper (Eve). Cooperative transmission is explored to secure communication between Alice and Bob, while ensuring the desired quality of service (QoS) at Charlie’s receiver. We provide a transmit design for outage constrained secrecy rate maximization, taking both security and QoS constraints into account. Unlike the conventional cooperative security that adopts a fixed transmission scheme, we propose a mechanism for transmit strategy adaptation with security protection. Specifically, the proposed cooperative transmission is replaced by a cooperative jamming scheme if either security or QoS constraint is not satisfied. Numerical results confirm that our design enables dynamic transmission, and thus is flexible and environment-adaptive.
Autors: Lin Hu;Hong Wen;Bin Wu;Jie Tang;Fei Pan;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 524 - 527
Publisher: IEEE
 
» Adaptive Weighted Sensing With Simultaneous Transmission for Dynamic Primary User Traffic
Abstract:
In practical scenarios with random arrival and departure of primary users (PUs), existing simultaneous sensing and transmission schemes allocated the same weight to each sample, and did not consider low signal-to-noise ratio (SNR) situations. This paper proposes an adaptive weighted sensing scheme with simultaneous transmission for dynamic PU traffic. It uses a power function based on the corresponding sampling sequence and could reveal the actual PU state in near real time. The power exponent is further adjusted to the sensing situations to achieve lowest false alarm probability under a certain detection probability constraint. Then, an analytical model considering all possible PU state transitions is developed to evaluate achievable interference, throughput, and energy efficiency. Furthermore, the optimal frame duration yielding both optimal false alarm probability and throughput is computed. After that, a fast search algorithm is proposed to track the optimal duration at an exponential convergence rate. Simulation results are provided to validate the analytical model and demonstrate the improvement in low SNR. The results indicate that the proposed scheme can achieve lower false alarm probability and higher energy efficiency over a wide SNR range than that of the existing weighting schemes, which are based on probability, geometric sequence, and equal weighting.
Autors: Min Deng;Bin-Jie Hu;Xiaohuan Li;
Appeared in: IEEE Transactions on Communications
Publication date: Mar 2017, volume: 65, issue:3, pages: 992 - 1004
Publisher: IEEE
 
» Adaptively Biased 60-GHz Doherty Power Amplifier in 65-nm CMOS
Abstract:
A 60-GHz Doherty power amplifier (PA) implemented in 65-nm bulk CMOS process is proposed. A novel adaptive biasing network is devised to dynamically adjust the bias voltage of the peaking PA, counteracting its low transconductance caused by the class-C biasing condition. At 60 GHz, the fabricated Doherty PA achieves 22% drain efficiency with a saturation power of 13.2 dBm. The measured results show that over 17% and 8% efficiencies at peak and 6-dB back-off power regions are achieved, respectively, from 57 to 64 GHz.
Autors: Shichang Chen;Gaofeng Wang;Zhiqun Cheng;Pei Qin;Quan Xue;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Mar 2017, volume: 27, issue:3, pages: 296 - 298
Publisher: IEEE
 
» Additive Bounds of Minimum Output Entropies for Unital Channels and an Exact Qubit Formula
Abstract:
We find an upper bound for the minimum output entropy of a unital quantum channel, and obtain an exact formula for general qubit channels. Our techniques incorporate the Rényi entropies, particularly, with Rényi parameter . Moreover, since our upper bound is additive under tensor product, we get as a corollary an upper bound for the classical capacity of unital quantum channels. Interestingly, our upper bound for the classical capacity depends only on the operator norm of matrix representations of channels on the space of traceless Hermitian operators, and is tight in the sense that it gives the precise quantity of classical capacity of the Werner–Holevo channel. As an example, we study quantum channels with operator sum representation that is made of the discrete Weyl operators (generalized Pauli operators), and explain how our formula works in this case. Finally, we find new examples for which the minimum output Rényi 2-entropy is additive.
Autors: Motohisa Fukuda;Gilad Gour;
Appeared in: IEEE Transactions on Information Theory
Publication date: Mar 2017, volume: 63, issue:3, pages: 1818 - 1828
Publisher: IEEE
 
» Advances in Automotive Radar: A framework on computationally efficient high-resolution frequency estimation
Abstract:
Radar technology is used for many applications of advanced driver assistance systems (ADASs) and is considered as one of the key technologies for highly automated driving (HAD). An overview of conventional automotive radar processing is presented and critical use cases are pointed out in which conventional processing is bound to fail due to limited frequency resolution. Consequently, a flexible framework for computationally efficient high-resolution frequency estimation is presented. This framework is based on decoupled frequency estimation in the Fourier domain, where high-resolution processing can be applied to either the range, relative velocity, or angular dimension. Real data obtained from series-production automotive radar sensor are presented to show the effectiveness of the presented approach.
Autors: Florian Engels;Philipp Heidenreich;Abdelhak M. Zoubir;Friedrich K Jondral;Markus Wintermantel;
Appeared in: IEEE Signal Processing Magazine
Publication date: Mar 2017, volume: 34, issue:2, pages: 36 - 46
Publisher: IEEE
 
» Aggregation Effects and Population-Based Dynamics as a Source of Therapy Resistance in Cancer
Abstract:
Objective: Evolution of resistance allows cancer cells to adapt and continue proliferating even when therapy is initially very effective. Most investigations of treatment resistance focus on the adaptive phenotypic properties of individual cells. We propose that the resistance of a single cell to therapy may extend beyond its own phenotypic and molecular properties and be influenced by the phenotypic properties of surrounding cells and variations in cell density. Similar variation exists in population densities of animals living in groups and can significantly affect the outcome of an external threat. Methods: We investigate aggregation effects in cancer therapy using Darwinian models that integrate phenotypic properties of individual cells and common population effects found in nature to simulate the dynamics of resistance and sensitivity in the diverse cellular environments within cancers. Results: We demonstrate that the density of cancer cell populations can profoundly influence response to chemotherapy independent of the properties of individual cells. Most commonly, these aggregation effects benefit the tumor allowing cells to survive even with phenotypic properties that would render them highly vulnerable to therapy in the absence of population effects. Conclusion: We demonstrate aggregation effects likely play a significant role in conferring resistance to therapy on tumor cells that would otherwise be sensitive to treatment. Significance: The potential role of aggregation in outcomes from cancer therapy has not been previously investigated. Our results demonstrate these dynamics may play a key role in resistance to therapy and could be used to design evolutionarily-enlightened therapies that exploit aggregation effects to improve treatment outcomes.
Autors: Joel S. Brown;Jessica J. Cunningham;Robert A. Gatenby;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Mar 2017, volume: 64, issue:3, pages: 512 - 518
Publisher: IEEE
 
» Aging Assessment and Design Enhancement of Randomized Cache Memories
Abstract:
Critical real-time systems require the estimation of the worst-case execution time (WCET) for scheduling purposes and resource budgeting. Measurement-based probabilistic timing analysis (MBPTA) has been shown recently as a powerful approach for WCET estimation. MBPTA builds upon time-randomized cache memories. While aging has been deeply analyzed for conventional time-deterministic caches (i.e., implementing modulo placement), little work has been done to assess the reliability of time-randomized caches. In this line, only the WCET analysis of faulty time-randomized caches has been introduced recently. However, the intrinsic robustness of randomized hardware designs has not been assessed yet. In this paper we perform, for the first time, an assessment of the agingrobustness of random placement cache designs: random modulo and hash-based random placement. We propose a new random modulo implementation preserving its key benefits in terms of low critical path impact, low miss rates and MBPTA compliance; while reducing hot-carrier injection aging by achieving a better, yet random, activity distribution across cache sets. On the other hand, we show that gains in terms of bias temperature instability aging are limited for random placement designs on their own.
Autors: David Trilla;Carles Hernandez;Jaume Abella;Francisco J. Cazorla;
Appeared in: IEEE Transactions on Device and Materials Reliability
Publication date: Mar 2017, volume: 17, issue:1, pages: 32 - 41
Publisher: IEEE
 
» Aging Benefits in Nanometer CMOS Designs
Abstract:
In this brief, we show that bias temperature instability (BTI) aging of MOS transistors, together with its detrimental effect for circuit performance and lifetime, presents considerable benefits for static power consumption due to subthreshold leakage current reduction. Indeed, static power reduces considerably, making CMOS circuits more energy efficient over time. Static power reduction depends on transistor stress ratio and operating temperature. We propose a simulation flow allowing us to properly evaluate the BTI aging of complex circuits in order to estimate BTI-induced power reduction accurately. Through HSPICE simulations, we show 50% static power reduction after only one month of operation, which exceeds 78% in ten years. BTI aging benefits for power consumption are also proven with experimental measurements.
Autors: Daniele Rossi;Vasileios Tenentes;Sheng Yang;Saqib Khursheed;Bashir M. Al-Hashimi;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Mar 2017, volume: 64, issue:3, pages: 324 - 328
Publisher: IEEE
 
» Air–Ground Channel Characterization for Unmanned Aircraft Systems Part II: Hilly and Mountainous Settings
Abstract:
The use of unmanned aircraft systems (UAS) is expanding rapidly. For safe and reliable integration of UAS into the National Airspace System (NAS), control and nonpayload communication (CNPC) system requirements are being developed. The air-to-ground (AG) channel characteristics essentially determine CNPC link performance. The National Aeronautics and Space Administration (NASA) Glenn Research Center has sponsored a comprehensive AG channel measurement campaign in 2013 in both the L- and C-bands recently allocated for UAS. These measurements covered nearly all typical ground site (GS) local environments, including over water, hilly, mountainous, suburb, and near urban. As a continuation of results reported for the over-water scenarios, a description of the measurement campaign, measured results, and complete AG channel models for hilly and mountainous terrains are provided in this paper. The path loss is modeled by a modified log-distance path loss model with a correction for flight direction; path loss results are close to those of free space. A strong ground reflection was observed only for some small portions of some of the flight paths. The small-scale fading is well modeled by the Ricean distribution with a -factor of 29.4 dB in the C-band and 12.8 dB in the L-band. The interband signals are uncorrelated. The spatial correlation for the two intraband channels with an aircraft antenna separation of 1.8 m is greater than 0.85. The C-band root-mean-square delay spread (RMS-DS) is 10 ns most of the time, with a maximum of 1 in hilly terrain and 180 ns in mountainous terrain. Tapped delay line (TDL) models accounting for the line of sight (LOS) and up to seven intermittent multipath components (MPCs) were developed, including the MPCs' probability of occurrence, relative power, p- ase, duration, and excess delay.
Autors: Ruoyu Sun;David W. Matolak;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 1913 - 1925
Publisher: IEEE
 
» All-Digital High Resolution D/A Conversion by Dyadic Digital Pulse Modulation
Abstract:
In this paper, the limitations of digital-to-analog (D/A) conversion by Digital Pulse Width Modulation (DPWM) are addressed and the novel Dyadic Digital Pulse Modulation (DDPM) technique for all-digital, low cost, high resolution, Nyquist-rate D/A conversion is proposed. Thanks to the spectral characteristics of the new modulation, in particular, the requirements of the filter needed to extract the baseband component of DPWM signals can be significantly released so that to be suitable to inexpensive integration on silicon in analog interfaces for nanoscale integrated systems. After the new DDPM technique and its properties are introduced on a theoretical basis, the implementation of a D/A converter (DAC) based on the proposed modulation is addressed and its performance in terms of noise and linearity is discussed. A 16-bit DDPM-DAC prototype is finally synthesized on a field-programmable gate array (FPGA) and experimentally characterized.
Autors: Paolo S. Crovetti;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Mar 2017, volume: 64, issue:3, pages: 573 - 584
Publisher: IEEE
 
» Amplitude-Saturated Nonlinear Output Feedback Antiswing Control for Underactuated Cranes With Double-Pendulum Cargo Dynamics
Abstract:
When modeling cranes, the hook and the suspended cargo are usually regarded roughly as one mass point for simplicity, i.e., the cargo swing is modeled as that of a single pendulum. However, in practice, when the hook mass is nonnegligible or the cargo has a large size, the crane always exhibits double-pendulum swing dynamics, which is much more complicated and makes most existing control methods unapplicable. In addition, all existing closed-loop controllers for (double-pendulum) cranes require full state feedback, while velocities are unavailable in most cases. Moreover, they need to linearize the nonlinear crane model and cannot respect the actuator's practical saturation constraint, which may probably lead to actuator saturation and badly degrade the control performance (even unstable). In response to these practical issues, we suggest a novel amplitude-saturated output feedback (OFB) control approach for underactuated crane systems exhibiting double-pendulum effects. We provide explicit Lyapunov-based analysis to rigorously prove that the equilibrium point of the closed-loop system is almost globally asymptotically stable, without any approximation to the original nonlinear dynamics. As far as we know, this paper presents the first closed-loop control method that can achieve control for an underactuated double-pendulum crane with merely OFB and theoretically-guaranteed saturated control efforts. Hardware experimental results demonstrate the superior performance of the proposed approach over existing methods and its strong robustness as well.
Autors: Ning Sun;Yongchun Fang;He Chen;Biao Lu;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2135 - 2146
Publisher: IEEE
 
» An Absolute Secure Wire-Line Communication Method Against Wiretapper
Abstract:
This letter proposes a security method for wire-line point-to-point communication based on the information theory. The proposed system replaces the conventional receiver by a full-duplex node which can, not only, receive the confidential signal, but also deliver artificial noise to impair the channel of wiretapper observation between the two legitimate partners. The power ratio of the signal to the artificial noise is a key factor for guaranteeing absolute secure communication. The theoretical work is carried out in the model of physical layer security on the assumption that the wiretapper can perform the optimum detection, including with colluding structure. Numerical results are presented for demonstrating the effectiveness of the proposed approach.
Autors: Sanjun Liu;Meng Ma;Yunzhou Li;Yingyang Chen;Bingli Jiao;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 536 - 539
Publisher: IEEE
 
» An Accurate Analytical Current Model of Double-gate Heterojunction Tunneling FET
Abstract:
A continuous accurate analytical drain current model considering the effect of the inversion charge is presented for the double-gate heterojunction tunneling FET. The band-to-band tunneling current is calculated analytically in terms of the integration with respect to the generation rate using a tangent line approximation method. The accuracy of the model is validated by comparing it with the TCAD simulation. The model, applied to the example of GaAsSb/InGaAs heterojunction, predicts the surface potential profiles, and characteristics accurately. Under different device parameters (gate oxide dielectric constant, gate oxide thickness, and heterojunction materials), the validity of the model is demonstrated by its agreement with the TCAD simulation.
Autors: Yunhe Guan;Zunchao Li;Wenhao Zhang;Yefei Zhang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 938 - 944
Publisher: IEEE
 
» An Acoustic Positioning Buoy
Abstract:
Real-time positioning for autonomous underwater vehicles (AUVs) is an important but very complex problem. This article documents the overall process of creating a buoy system for AUV positioning. Similar to Global Positioning System (GPS) electromagnetic signals, the buoys were designed to transmit acoustic signals. These signals would be received and processed by the AUV, allowing the AUV to position itself in real time. This is a system-level report and does not go into any great detail on advanced topics. This project was led by Dr. Harold (Bud) Vincent, a professor at the University of Rhode Island and an expert in underwater acoustics.
Autors: Jeremiah Sullivan;
Appeared in: IEEE Potentials
Publication date: Mar 2017, volume: 36, issue:2, pages: 16 - 19
Publisher: IEEE
 
» An Active Absorber Based on Nonvolatile Floating-Gate Graphene Structure
Abstract:
An active absorber with nearly zero static power consumption is proposed based on nonvolatile floating-gate graphene structure. Such absorber has almost no static power consumption benefited from the nonvolatile design. In such design, the central graphene can capture the tunneled electrons under the positive applied voltage, but cannot release these electrons after removing the voltage since it is electrically isolated from the external electrodes. Therefore, no extra power is needed to sustain the conductivity of graphene. Moreover, our proposed absorber exhibits an extremely strong absorption capacity. Even taking the strict condition for the bandwidth where all the absorptivity inside the bandwidth are larger than 90% as criterion, the proposed absorber provides more than 60 GHz absorption bandwidth which is twice larger than previous results. Furthermore, the proposed absorber shows high tolerance against large incidence angle (), different polarizations and nonideal factors of graphene. The results may promote various future nonvolatile absorber designs.
Autors: Xi-Liang Peng;Ran Hao;Wenchao Chen;Hong-sheng Chen;Wen-Yan Yin;Er-Ping Li;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Mar 2017, volume: 16, issue:2, pages: 189 - 195
Publisher: IEEE
 
» An Active Damping Method Based on a Supercapacitor Energy Storage System to Overcome the Destabilizing Effect of Instantaneous Constant Power Loads in DC Microgrids
Abstract:
This paper presents a novel active damping method to overcome instability problems of dc microgrids (MGs) caused by constant power loads (CPLs). This method is implemented based on the existing energy storage system (ESS) in the dc MGs. As an indispensable part in the dc MGs, the ESS in this paper is used for more than just compensating the conventional power unbalance in the system, it has taken an additional responsibility and is used for adjusting the system damping to deal with the instability problems induced by the CPLs as well. First, the stability criteria of a simplified dc MG are analyzed. Based on this, an active damping method that aims at virtually reshaping the loads in the dc MG is introduced. With the proposed method, which is realized by a supercapacitor ESS in this paper, the CPLs in the system are virtually reduced and the resistive loads are virtually increased. Therefore, the destabilizing effect of the CPLs in the dc MG is eliminated. Simulations and experiments are conducted and the effectiveness of the proposed method is verified. This method is suitable to be applied in the dc MG with various elements and variable operation modes.
Autors: Xiaoyong Chang;Yongli Li;Xuan Li;Xiaolong Chen;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Mar 2017, volume: 32, issue:1, pages: 36 - 47
Publisher: IEEE
 
» An Adaptive Disturbance Rejection Method With Stability Enhancement Using Adjustable Dead Zone for Hard Disk Drives
Abstract:
We report a stability enhancement algorithm for adaptive disturbance rejection with applications in hard disk drives. The adaptive disturbance rejection algorithm can compensate for disturbances in real time; however, to deploy the method in the field, difficulties in maintaining the stability of the servo loop in response to variable disturbances must be resolved. To address these issues, we apply an adjustable dead zone in the adaptation scheme. This method provides adaptive control while maintaining stability of the servo loop regardless of the applied disturbance, allowing successful rejection of disturbances in real time. To solve it, a dead-zone algorithm is suggested, which leads to a performance degradation in disturbance rejection. Accordingly, we are suggesting a new design for a Q-filter in the adaptive disturbance observer. This advanced Q-filter makes the structure of the entire system similar to a peak-notch filter. In this paper, we will verify the effect of the suggested method through simulation.
Autors: Jae-Seong Lee;Sung-Yong Lim;Inho Kim;Wooyoung Jeong;SungWon Park;Hyunseok Yang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Mar 2017, volume: 53, issue:3, pages: 1 - 9
Publisher: IEEE
 
» An Adaptive Range-Angle-Doppler Processing Approach for FDA-MIMO Radar Using Three-Dimensional Localization
Abstract:
High pulse repetition frequency incurs range ambiguity in radar systems, which in turn results in clutter suppression performance degradation and parameter estimation ambiguities. To tackle this issue, this paper proposes an adaptive range-angle-Doppler processing approach with airborne frequency diverse array (FDA) for multiple-input multiple-output (MIMO) radar. The FDA employs a small frequency increment across array elements and introduces additional controllable degrees-of-freedom (DOFs) in range dimension in the transmit antenna. Thus, it is able to perform range-angle-Doppler processing by exploiting the DOFs in transmit, receive, and pulse dimensions in the FDA-MIMO radar. By properly designing the frequency increment of the FDA, the clutter spectra of different ambiguous range regions can be discriminable in the transmit-receive spatial domains. As a result, multiple beams are formed in the transmit spatial, receive spatial, and Doppler domains and clutters from different range regions can be suppressed. An enhanced three-dimensional localization technique is proposed for the case with severe range ambiguity problem, which evidently reduces the dimensions of the processor and efficiently suppresses clutter in practical applications. Several numerical examples are presented to verify the effectiveness of the proposed approach.
Autors: Jingwei Xu;Guisheng Liao;Yuhong Zhang;Hongbing Ji;Lei Huang;
Appeared in: IEEE Journal of Selected Topics in Signal Processing
Publication date: Mar 2017, volume: 11, issue:2, pages: 309 - 320
Publisher: IEEE
 
» An Agile Post-Silicon Validation Methodology for the Address Translation Mechanisms of Modern Microprocessors
Abstract:
Detection of bugs in the complex address translation mechanisms (ATMs) of modern microprocessors is much harder than in other microprocessor structures because their output (the physical address) is not directly observable to program or architecture visible locations during post-silicon validation. Errata reports, by major microprocessor vendors about ATM-related bugs found after chips massive production, plea for more efficient validation solutions. In this paper, we formulate the problem of post-silicon validation of microprocessors’ address translation hardware, by defining a comprehensive set of bug models. We then propose an ISA-independent post-silicon validation methodology for the ATMs of high-end microprocessors. The method detects ATM bugs right after their manifestation, reveals mismatches due to them and facilitates diagnosis and debug. Our experiment evaluation on an enhanced version of the Gem5 simulator (including MMU caches) demonstrates the effectiveness of the method in detecting known ATM bugs, five orders of magnitude faster than traditional approaches.
Autors: George Papadimitriou;Athanasios Chatzidimitriou;Dimitris Gizopoulos;Ronny Morad;
Appeared in: IEEE Transactions on Device and Materials Reliability
Publication date: Mar 2017, volume: 17, issue:1, pages: 3 - 11
Publisher: IEEE
 
» An All-Digital, Single-Bit RF Transmitter for Massive MIMO
Abstract:
This paper presents an all-digital transmitter solution particularly suited for Massive multiple-input and multiple-output (MIMO) systems for mobile communications. Massive MIMO is a key candidate to address the challenges of future mobile communication standards, especially to provide higher capacity in dense urban scenarios. While the required communication theory is elaborated to a great extend, the transceiver hardware complexity remains a potential economical show-stopper. This paper demonstrates that all-digital transmitters can be employed to reduce size, cost, and engineering effort of heavily parallelized transmit architectures. Therefore, today’s all-digital transmitter concepts are analyzed and improvements are suggested to increase performance and feasibility. The realized setups prove that the key specifications of mobile communication standards can be met utilizing dedicated integrated circuits or even by using off-the-shelf FPGAs and their high-speed interfaces. We show that we can generate 8 parallel 5 MHz LTE signals at 2.6 GHz out of a single FPGA with an ACPR of 48 dB with a coding efficiency of 50% using only binary waveforms.
Autors: Daniel Markert;Xin Yu;Holger Heimpel;Georg Fischer;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Mar 2017, volume: 64, issue:3, pages: 696 - 704
Publisher: IEEE
 
» An All-MOSFET Sub-1-V Voltage Reference With a —51 –dB PSR up to 60 MHz
Abstract:
This paper presents a voltage reference (VR) with a power supply rejection (PSR) better than 50 dB for frequencies of up to 60 MHz, and uses MOSFETs in strong inversion. Another innovation is a compact MOSFET low-pass filter, which was developed along with a feedback technique for a wide-bandwidth PSR not achieved in previous works. The proposed all-MOSFET VR was fabricated using a standard CMOS process. It achieves a minimum temperature coefficient of 6.5 ppm/°C for temperatures from −30 °C to 110 °C. The line regulation is 0.076%/V for a step from 0.8 to 2.2 V supply voltage with 360 nW power consumption at room temperature and an area of 0.0143 mm.
Autors: Nashiru Alhasssan;Zekun Zhou;Edgar Sánchez Sinencio;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Mar 2017, volume: 25, issue:3, pages: 919 - 928
Publisher: IEEE
 
» An Analog CVNS-Based Sigmoid Neuron for Precise Neurochips
Abstract:
In this paper, the design and implementation of an analog sigmoid neuron is presented. The activation function of the proposed neuron is implemented based on the piecewise linear approximation in the analog domain. The proposed neuron provides the required accuracy that cannot be achieved in general by analog neural network implementations. General digital outputs of a sigmoid neuron are replaced with fewer analog digits of the continuous valued number system (CVNS), while at the same time maximum approximation error is kept the same as the digital architectures. The proposed CVNS neuron resulted in an optimal ASIC implementation and is suitable for neurochips with on-chip learning. The VLSI implementation of the neuron is carried out using current-mode circuits. The implementation results compare favorably with previously developed structures in terms of area, delay, and power consumption. The proposed neuron structure occupies 28% less area compared with the state-of-the-art methods and it has two times lower power delay.
Autors: Babak Zamanlooy;Mitra Mirhassani;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Mar 2017, volume: 25, issue:3, pages: 894 - 906
Publisher: IEEE
 
» An Analytical Model for Double-Gate Tunnel FETs Considering the Junctions Depletion Regions and the Channel Mobile Charge Carriers
Abstract:
In this paper, we present an accurate analytical potential model for the double-gate tunnel FETs (DG-TFETs) by solving Poisson’s equation with appropriate boundary conditions. Taking the mobile charge carriers in the channel and the depletion regions inside the source and drain into account, the model predicts the electrostatic potential of the homojunction device in all regions of the device operation more accurately, compared with the predictions of the previously reported models. The potential model is utilized for developing some models for important quantities in TFETs, such as lateral electric field, minimum tunneling length, and drain current. Owing to the physical and analytical nature of the developed models, one can pursue the influence of the transistor parameters on the electrical characteristics of DG-TFETs. To assess the accuracy of the proposed models, the results of the models are compared to those of the numerical simulations and found to be accurately predicting the simulation results for different device parameters.
Autors: Saeed Mohammadi;Hamid Reza Tajik Khaveh;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 1276 - 1284
Publisher: IEEE
 
» An Analytical Time–Domain Expression for the Net Ripple Produced by Parallel Interleaved Converters
Abstract:
We apply modular arithmetic and Fourier series to analyze the superposition of interleaved triangular waveforms with identical amplitudes and duty ratios. Here, interleaving refers to the condition when a collection of periodic waveforms with identical periods is uniformly phase shifted across one period. The main result is a time–domain expression that provides an exact representation of the summed and interleaved triangular waveforms, where the peak amplitude and parameters of the time-periodic component are all specified in closed form. Analysis is general and can be used to study various applications in multiconverter systems. This model is unique not only in that it reveals a simple and intuitive expression for the net ripple, but its derivation via modular arithmetic and Fourier series is distinct from prior approaches. The analytical framework is experimentally validated with a system of three parallel converters under time-varying operating conditions.
Autors: Brian B. Johnson;Philip T. Krein;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Mar 2017, volume: 64, issue:3, pages: 289 - 293
Publisher: IEEE
 
» An Angularly Stable Dual-Band FSS With Closely Spaced Resonances Using Miniaturized Unit Cell
Abstract:
A novel miniaturized-element dual-band frequency selective surface (FSS) with closely spaced resonance is presented in this letter. The proposed FSS comprises of meander lines printed on a single-layer dielectric substrate to provide dual stopband characteristic. Compared to previously published spatial filters, the proposed FSS has better miniaturization characteristic having the unit-cell size of , where corresponds to free space wavelength of the lower resonance frequency. In addition, the operating bands are closely located exhibiting the frequency ratio as low as 1.29. The surface current distribution and the equivalent circuit model are illustrated to explain the resonance behavior of the designed FSS. Furthermore, the proposed structure is polarization-independent and angularly stable for both TE and TM polarizations. A prototype of the dual-band FSS is fabricated and measured, which validates the simulated responses under normal and oblique incidence.
Autors: Saptarshi Ghosh;Kumar Vaibhav Srivastava;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Mar 2017, volume: 27, issue:3, pages: 218 - 220
Publisher: IEEE
 
» An Artificial-Noise-Aided Hybrid TS/PS Scheme for OFDM-Based SWIPT Systems
Abstract:
We propose a new artificial-noise aided hybrid time-switching/power-splitting scheme for orthogonal frequency-division multiplexing (OFDM) systems to securely transmit data and transfer energy to a legitimate receiving node. In our proposed scheme, the cyclic prefix has two more benefits in addition to the cancellation of the inter-symbol interference between the OFDM blocks. First, it enables the legitimate transmitter to send artificial-noise (AN) vectors in a way such that the interference can be canceled at the legitimate receiver prior to information decoding. Second, its power is used to energize the legitimate receiver. We optimize the cyclic prefix length, the time-switching and power-splitting parameters, and the power allocation ratio between the data and AN signals at the legitimate transmitter to maximize the average secrecy rate subject to a constraint on the average energy transfer rate at the legitimate receiver. Numerical results demonstrate that our proposed scheme can achieve up to 23% average secrecy rate gain relative to a pure power-splitting scheme.
Autors: Ahmed El Shafie;Kamel Tourki;Naofal Al-Dhahir;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 632 - 635
Publisher: IEEE
 
» An Automatic User-Adapted Physical Activity Classification Method Using Smartphones
Abstract:
In recent years, an increasing number of people have become concerned about their health. Most chronic diseases are related to lifestyle, and daily activity records can be used as an important indicator of health. Specifically, using advanced technology to automatically monitor actual activities can effectively prevent and manage chronic diseases. The data used in this paper were obtained from acceleration sensors and gyroscopes integrated in smartphones. We designed an efficient Adaboost-Stump running on a smartphone to classify five common activities: cycling, running, sitting, standing, and walking and achieved a satisfactory classification accuracy of 98%. We designed an online learning method, and the classification model requires continuous training with actual data. The parameters in the model then become increasingly fitted to the specific user, which allows the classification accuracy to reach 95% under different use environments. In addition, this paper also utilized the OpenCL framework to design the program in parallel. This process can enhance the computing efficiency approximately ninefold.
Autors: Pengfei Li;Yu Wang;Yu Tian;Tian-Shu Zhou;Jing-Song Li;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Mar 2017, volume: 64, issue:3, pages: 706 - 714
Publisher: IEEE
 
» An Effective Approach of Improving Electrical and Thermo-Mechanical Reliabilities of Through-Silicon Vias
Abstract:
An effective approach is proposed to improve the electrical and thermo-mechanical reliabilities of through-silicon vias (TSVs) with the addition of a grounded highly doped layer (HDL) around TSV. On the electrical aspect, the reduction of the peak noise induced by the proposed TSV configuration reaches more than 83% in time domain and about 15 dB in frequency domain compared with that of the TSV without HDL. On the thermo-mechanical aspect, the keep-out zone induced by the proposed TSV configuration decreases by as much as 3.9 (38.2%) compared with coaxial TSV with metal guard ring. Furthermore, the proposed TSV configuration proves to be process realizable.
Autors: Fengjuan Wang;Ningmei Yu;
Appeared in: IEEE Transactions on Device and Materials Reliability
Publication date: Mar 2017, volume: 17, issue:1, pages: 106 - 112
Publisher: IEEE
 
» An Effective Multiuser Detection Scheme for MPR Random Access Networks
Abstract:
Packet collision is a well-known severe impairment in ALOHA-based networks and, more generally, in any random access network. As a consequence, several methodologies have been considered with the aim of lowering the resulting performance degradation. A novel multiuser detection scheme exploiting channel diversity to separate collided signals is proposed here to enable multiple packet reception capability in random access schemes. The performance of this approach is analytically derived and optimized in terms of network throughput, and compared with that of different alternatives. The overall performance in terms of throughput shows the effectiveness of the proposed scheme in different operating conditions.
Autors: Giulio Bartoli;Norman C. Beaulieu;Romano Fantacci;Dania Marabissi;
Appeared in: IEEE Transactions on Communications
Publication date: Mar 2017, volume: 65, issue:3, pages: 1119 - 1130
Publisher: IEEE
 
» An Effective SC-PML Implementation for Iterative WLP-FDTD Method With Reduced Splitting Error
Abstract:
In this letter, a stretched coordinate (SC) perfectly matched layer (PML) is presented for the iterative finite-difference time-domain (FDTD) method based on weighted Laguerre polynomials (WLPs). By applying the iterative scheme, the splitting error in WLP-FDTD is reduced. The SC-PML can be easily combined with a complex-frequency-shifted factor to improve the performance for low frequency and evanescent wave absorption. Numerical example demonstrates the accuracy and effectiveness of the proposed algorithm.
Autors: Yun Fang;Xiao-Li Xi;Jiang-Fan Liu;Yu-Rong Pu;Jin-Sheng Zhang;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Mar 2017, volume: 27, issue:3, pages: 209 - 211
Publisher: IEEE
 
» An Efficient and Flexible Hardware Implementation of the Dual-Field Elliptic Curve Cryptographic Processor
Abstract:
Elliptic curve cryptography (ECC) has been widely used for the digital signature to ensure the security in communication. It is important for the ECC processor to support a variety of ECC standards to be compatible with different security applications. Thus, a flexible processor which can support different standards and algorithms is desired. In this paper, an efficient and flexible dual-field ECC processor using the hardware–software approach is presented. The proposed processor can support arbitrary elliptic curve. An elaborate modular arithmetic logic unit is designed. It can perform basic modular arithmetic operations and achieve high efficiency. Based on our designed instruction set, the processor can be programmed to perform various point operations based on different algorithms. To demonstrate the flexibility of our processor, a point multiplication algorithm with power analysis resistance is adopted. Our design is implemented in the field-programmable gate array platform and also in the application-specified integrated circuit. After implemented in the 55 nm CMOS process, the processor takes between 0.60 ms (163 bits ECC) and 6.75 ms (571 bits ECC) to finish one-point multiplication. Compared to other related works, the merits of our ECC processor are the high hardware efficiency and flexibility.
Autors: Zilong Liu;Dongsheng Liu;Xuecheng Zou;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2353 - 2362
Publisher: IEEE
 
» An Efficient Approach for Fault Detection, Isolation, and Data Recovery of Self-Validating Multifunctional Sensors
Abstract:
A novel fault detection, isolation, and data recovery (FDIR) approach for self-validating multifunctional sensors is presented in this paper. To improve the fault detection accuracy under multiple steady conditions for multifunctional sensors, a sparse non-negative matrix factorization (SNMF)-based model is employed to accomplish fault detection through a combination of newly proposed and squared prediction error (SPE) statistics. Furthermore, a self-adaptive multiple-variable reconstruction strategy (SMVR) is proposed to achieve high accuracy on multiple-fault isolation and data recovery for faulty sensitive units. The performance of the proposed approach is fully verified in a real experimental system for self-validating multifunctional sensors, and it is compared with those of other fault detection models, such as principal component analysis (PCA), non-negative matrix factorization (NMF), and fault isolation algorithms, such as PCA-based contribution plots and SNMF-based contribution plots. The experimental results demonstrate that the proposed approach provides an excellent solution to the FDIR of self-validating multifunctional sensors.
Autors: Jingli Yang;Yinsheng Chen;Lili Zhang;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Mar 2017, volume: 66, issue:3, pages: 543 - 558
Publisher: IEEE
 
» An Efficient Domain Decomposition Parallel Scheme for Leapfrog ADI-FDTD Method
Abstract:
A flexible and universal domain decomposition parallel scheme is proposed for the unconditionally stable finite-difference time-domain (FDTD) method. The leapfrog alternating direction implicit FDTD (ADI-FDTD) method is employed to eliminate the restriction of the Courant–Friedrichs–Lewy stability condition. The proposed domain decomposition parallel implementation of the leapfrog ADI-FDTD method is more flexible with process allocation and requires fewer data communications. A buffer region is introduced to decouple the interactions between neighboring subdomains at each time step. Electromagnetic simulations are presented to demonstrate the applicability, accuracy, and efficiency of the proposed method.
Autors: Huaguang Bao;Rushan Chen;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Mar 2017, volume: 65, issue:3, pages: 1490 - 1494
Publisher: IEEE
 
» An Efficient Method of Power Spectral Density Estimation for On-Chip IR-UWB Transmitter Self-Calibration
Abstract:
In ultra-wideband impulse radio communications, process, voltage, and temperature variations may impact the operation of emitters by modifying the emitted power spectral density. In order to compensate the impact of such variations and to respect the spectral emission masks, self-calibration systems able to estimate the output power spectral density have to be integrated in ultra-wideband impulse radio transmitters. In this paper, a new power spectral density estimation method for ultra-wideband impulse radio signals is presented. Unlike the discrete Fourier transform classically used to estimate the power spectral density, the proposed method, which is based on the measurement of the time varying envelope and instantaneous frequency of the emitted pulse, preserves a link between the time and the frequency domain thanks to a piece-wise approximation of these waveforms. This time-to-frequency link enables a straightforward pulse shape control by using simple control methods and allows to comply with spectral masks required by ultra-wideband communication regulations and standards such as the IEEE 802.15.4a. Thus, both envelope and instantaneous frequency extraction techniques are introduced for acquisition of these time domain waveforms in ultra-wideband impulse radio domain. The proposed techniques are validated and allow to consider future hardware implementation in order to build on-chip calibration systems for ultra-wideband transmitters.
Autors: Anthony Goavec;Mykhailo Zarudniev;Rémy Vauché;Frédéric Hameau;Jean Gaubert;Eric Mercier;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Mar 2017, volume: 64, issue:3, pages: 686 - 695
Publisher: IEEE
 
» An Efficient Multiple Access Coordination Scheme for OFDMA WLAN
Abstract:
A new hybrid multiple access coordination scheme (HMAC) that increases channel utilization for orthogonal frequency-division multiple access wireless local area network is presented. This scheme is based on a mixture of centralized access control and distributed random access to maximize channel utilization. Remarkably, HMAC allows two schemes to function at the same time, not alternatively. Performance evaluation results show notable improvement on channel utilization, which is mainly based on the efficient way how we handle uplink traffic.
Autors: Jiseon Lee;Cheeha Kim;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 596 - 599
Publisher: IEEE
 
» An Efficient Polarity Detection Technique for Thermoelectric Harvester in L-based Converters
Abstract:
This paper presents a new method for detecting and reversing the polarity of a low-voltage thermoelectric generator (TEG) in inductor-based converters. The proposed technique makes use of the inductor response to a voltage change due to the flip in the TEG polarity. The inductor voltage provides two distinguishable states which correspond to the normal and the reversed TEG polarity. A switch matrix circuit is then used to correct the polarity by physically reversing the TEG connection. The detection circuit along with the switch matrix provide a positive input voltage from the TEG to the inductor-based converter. The proposed technique is an efficient polarity detection with all-digital implementation, fully integrated, small area and power overhead. The prototype chip is fabricated in 65-nm CMOS and occupies an area of 0.09 mm2. Measurement results confirm a maximum efficiency of 70% at 50 mV TEG voltage and output current. The proposed technique is part of an autonomous thermal energy harvesting system that detects and corrects the TEG polarity.
Autors: Mohammad Alhawari;Baker Mohammad;Hani Saleh;Mohammed Ismail;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Mar 2017, volume: 64, issue:3, pages: 705 - 716
Publisher: IEEE
 
» An Efficient Small Data Transmission Scheme in the 3GPP NB-IoT System
Abstract:
This letter proposes an efficient small data transmission scheme in the narrow band (NB)-Internet of Things (IoT) system. For the efficient use of radio resources, the proposed scheme enables devices in an idle state to transmit a small data packet without the radio resource control connection setup process. This can improve the maximum number of supportable devices in the NB-IoT system which has insufficient radio resources. Numerical results have shown that the proposed scheme can increase the maximum number of supportable devices by about 60% compared with the conventional scheme.
Autors: Sung-Min Oh;JaeSheung Shin;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 660 - 663
Publisher: IEEE
 

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