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Electrical and Electronics Engineering publications abstract of: 05-2014 sorted by title, page: 0
» 1-V 365- 2.5-MHz Channel Selection Filter for 3G Wireless Receiver in 55-nm CMOS
Abstract:
This paper presents a novel 1-V 2.5-MHz continuous-time filter for 3G wireless application, fabricated using a standard 55-nm CMOS process. The four-pole filter topology includes a single pole-tracking Operational Amplifier (OPAMP) structure to achieve low in-band noise levels, high out-of-band linearity, and reduced power consumption. An automatic frequency tuning circuit is developed to compensate for process and environmental variations. The proposed filter achieves in-band noise of 18- and out-of-band IIP3 of 33 dBm within 365 . The out-of-band spurious-free dynamic range is measured at 76.7 dB, resulting in a figure-of-merit of .
Autors: Lo, T.;Lo, C.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: May 2014, volume: 22, issue:5, pages: 1164 - 1169
Publisher: IEEE
 
» 1.9-ps Jitter, 10.0-dBm-EMI Reduction Spread-Spectrum Clock Generator With Autocalibration VCO Technique for Serial-ATA Application
Abstract:
A spread-spectrum clock generator (SSCG) that is characterized by a low jitter voltage-controlled oscillator (VCO) with a high-frequency limiter and an autocalibration function is developed for a Serial-ATA application. The high-frequency limiter prevents the SSCG from going into an unlocked state. The proposed VCO achieved far less jitter than a conventional one because a proposed structure has fewer operating MOSs that are noise sources. The autocalibration technique calibrates the VCO sensitivity, the maximum frequency of the VCO output signal, and the characteristics of the limit function to prevent the SSCG from degrading an output jitter and an electromagnetic interference (EMI) reduction due to a process variation. The proposed SSCG with the autocalibration function was fabricated in a 0.13- CMOS process. The variation in the jitter in 250-cycles at 1.5 GHz with spread-spectrum clocking (SSC) is improved from 2.1-7.8 ps to 1.9–3.3 ps and the EMI reduction is achieved as 10.0 dBm by the proposed autocalibration technique.
Autors: Kawamoto, T.;Suzuki, M.;Noto, T.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: May 2014, volume: 22, issue:5, pages: 1118 - 1126
Publisher: IEEE
 
» 2014 RFIC Symposium
Abstract:
Describes the above-named upcoming conference event. May include topics to be covered or calls for papers.
Autors: Kushner, L.;Bakkaloglu, B.;Wang, A.;
Appeared in: IEEE Microwave Magazine
Publication date: May 2014, volume: 15, issue:3, pages: 66 - 69
Publisher: IEEE
 
» 2D Affine and Projective Shape Analysis
Abstract:
Current techniques for shape analysis tend to seek invariance to similarity transformations (rotation, translation, and scale), but certain imaging situations require invariance to larger groups, such as affine or projective groups. Here we present a general Riemannian framework for shape analysis of planar objects where metrics and related quantities are invariant to affine and projective groups. Highlighting two possibilities for representing object boundaries—ordered points (or landmarks) and parameterized curves—we study different combinations of these representations (points and curves) and transformations (affine and projective). Specifically, we provide solutions to three out of four situations and develop algorithms for computing geodesics and intrinsic sample statistics, leading up to Gaussian-type statistical models, and classifying test shapes using such models learned from training data. In the case of parameterized curves, we also achieve the desired goal of invariance to re-parameterizations. The geodesics are constructed by particularizing the path-straightening algorithm to geometries of current manifolds and are used, in turn, to compute shape statistics and Gaussian-type shape models. We demonstrate these ideas using a number of examples from shape and activity recognition.
Autors: Bryner, D.;Klassen, E.;Le, H.;Srivastava, A.;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: May 2014, volume: 36, issue:5, pages: 998 - 1011
Publisher: IEEE
 
» 3-D Cross-Point Array Operation on -Based Vertical Resistive Switching Memory
Abstract:
A comprehensive array operation scheme for a multilayer stacked 3-D vertical resistive random access memory (RRAM) cross-point array architecture is developed. Based on the proposed READ/WRITE scheme, each memory cell in the 3-D array can be randomly accessed. The fabricated -based bilayer vertical RRAM array with excellent device-to-device and layer-to-layer uniformity is applied to demonstrate the feasibility of the proposed operation scheme.
Autors: Gao, B.;Chen, B.;Liu, R.;Zhang, F.;Huang, P.;Liu, L.;Liu, X.;Kang, J.;Chen, H.;Yu, S.;Wong, H.P.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: May 2014, volume: 61, issue:5, pages: 1377 - 1381
Publisher: IEEE
 
» 3D Is Back!
Abstract:
Editor in chief Miguel Encarnação discusses the special issue on Interacting above and beyond the Display. He also introduces the magazine's newest editorial board member, Manuel M. Oliveira of the Federal University of Rio Grande do Sul.
Autors: Encarnacao, L.Miguel;
Appeared in: IEEE Computer Graphics and Applications
Publication date: May 2014, volume: 34, issue:3, pages: 6 - 7
Publisher: IEEE
 
» 3D Object Manipulation Using Virtual Handles with a Grabbing Metaphor
Abstract:
This technique lets users manipulate 3D objects as if they had actually grabbed them. It employs a grabbing metaphor to provide the mapping protocol for finding the desired reference frame for the object. The technique projects the user's hand into the virtual environment; a virtual-handle avatar provides feedback.
Autors: Kim, Taeho;Park, Jinah;
Appeared in: IEEE Computer Graphics and Applications
Publication date: May 2014, volume: 34, issue:3, pages: 30 - 38
Publisher: IEEE
 
» 3D Traffic Scene Understanding From Movable Platforms
Abstract:
In this paper, we present a novel probabilistic generative model for multi-object traffic scene understanding from movable platforms which reasons jointly about the 3D scene layout as well as the location and orientation of objects in the scene. In particular, the scene topology, geometry, and traffic activities are inferred from short video sequences. Inspired by the impressive driving capabilities of humans, our model does not rely on GPS, lidar, or map knowledge. Instead, it takes advantage of a diverse set of visual cues in the form of vehicle tracklets, vanishing points, semantic scene labels, scene flow, and occupancy grids. For each of these cues, we propose likelihood functions that are integrated into a probabilistic generative model. We learn all model parameters from training data using contrastive divergence. Experiments conducted on videos of 113 representative intersections show that our approach successfully infers the correct layout in a variety of very challenging scenarios. To evaluate the importance of each feature cue, experiments using different feature combinations are conducted. Furthermore, we show how by employing context derived from the proposed method we are able to improve over the state-of-the-art in terms of object detection and object orientation estimation in challenging and cluttered urban environments.
Autors: Geiger, A.;Lauer, M.;Wojek, C.;Stiller, C.;Urtasun, R.;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: May 2014, volume: 36, issue:5, pages: 1012 - 1025
Publisher: IEEE
 
» 3D Volume Drawing on a Potter's Wheel
Abstract:
The proposed 3D-volume-drawing interface can easily create various organic, artistic models. To provide intuitiveness, it adopts the metaphor of the potter's wheel. With one hand, users control a wooden wheel whose rotation is synchronized with that of the virtual space. A 3D depth camera captures the mid-air poses of the users' other hand, which the system translates into a virtual brush for interacting with a model. Through this configuration, the interface enables simultaneous view control and drawing. Also, because the brush's shape imitates the hand pose, the shape can vary. This makes our system flexible and maximizes expressiveness. With it, designers and artists can easily transfer their expertise to the virtual-modeling interface.
Autors: Cho, Sungmin;Baek, Dongyoub;Baek, Seung-Yeob;Lee, Kunwoo;Bang, Hyunwoo;
Appeared in: IEEE Computer Graphics and Applications
Publication date: May 2014, volume: 34, issue:3, pages: 50 - 58
Publisher: IEEE
 
» 7-nm FinFET CMOS Design Enabled by Stress Engineering Using Si, Ge, and Sn
Abstract:
Bandgap and stress engineering using group IV materials—Si, Ge, and Sn, and their alloys are employed to design a FinFET-based CMOS solution for the 7-nm technology node and beyond. A detailed simulation study evaluating the performance of the proposed design is presented. Through the use of a common strain-relaxed buffer layer for p- and n-channel MOSFETs and a careful selection of source/drain stressor materials, the CMOS design is shown to achieve performance benefits over strained Si, meet the requirements, and provide a path for continued technology scaling.
Autors: Gupta, S.;Moroz, V.;Smith, L.;Lu, Q.;Saraswat, K.C.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: May 2014, volume: 61, issue:5, pages: 1222 - 1230
Publisher: IEEE
 
» NN Query Processing Methods in Mobile Ad Hoc Networks
Abstract:
In this paper, we propose two beacon-less NN query processing methods for reducing traffic and maintaining high accuracy of the query result in mobile ad hoc networks (MANETs). In these methods, the query-issuing node first forwards a NN query using geo-routing to the nearest node from the point specified by the query (query point). Then, the nearest node from the query point forwards the query to other nodes close to the query point, and each node receiving the query replies with the information on itself. In this process, we adopt two different approaches: the Explosion (EXP) method and the Spiral (SPI) method. In the EXP method, the nearest node from the query point floods the query to nodes within a specific circular region, and each node receiving the query replies with information on itself. In the SPI method, the nearest node from the query point forwards the query to other nodes in a spiral manner, and the node that collects a satisfactory NN result transmits the result to the query-issuing node. Experimental results show that our proposed methods reduce traffic and achieve high accuracy of the query result, in comparison with existing methods.
Autors: Komai, Y.;Sasaki, Y.;Hara, T.;Nishio, S.;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: May 2014, volume: 13, issue:5, pages: 1090 - 1103
Publisher: IEEE
 
» Field-Effect Transistors With Graphene/Metal Heterocontacts
Abstract:
For the first time, n-type few-layer field-effect transistors (FETs) with graphene/Ti as the heterocontacts have been fabricated, showing more than 160-mA/mm drain current at 1- gate length with an ON-OFF current ratio of . The enhanced electrical characteristic is confirmed in a nearly 2.1 times improvement in ON-resistance and a 3.3 times improvement in contact resistance with heterocontacts compared with the FETs without graphene contact layer. Temperature-dependent study on heterocontacts has been also performed, still unveiling its Schottky contact nature. Transfer length method and a devised method have been introduced to study the contact resistance and Schottky barrier height in heterocontacts structure.
Autors: Du, Y.;Yang, L.;Zhang, J.;Liu, H.;Majumdar, K.;Kirsch, P.D.;Ye, P.D.;
Appeared in: IEEE Electron Device Letters
Publication date: May 2014, volume: 35, issue:5, pages: 599 - 601
Publisher: IEEE
 
» /InAlN/AlN/GaN MIS-HEMTs With 10.8 Johnson Figure of Merit
Abstract:
A high combination of three-terminal breakdown voltage and current gain cutoff frequency was achieved with /InAlN/AlN/GaN metal–insulator–semiconductor high-electron mobility transistors (MIS-HEMTs). A 1-nm gate dielectric was deposited ex situ in a molecular beam epitaxy system and used to increase the carrier density of the 2-D electron gas under an ultrathin InAlN/AlN (2.3 nm/1 nm) barrier. Passivated MIS-HEMTs with a gate length of 80 nm exhibited a drain current density greater than 1.1 A/mm, a peak intrinsic transconductance of 800 mS/mm, and a maximum frequency of oscillation of 230 GHz. The combination of of 114 GHz and of 95 V provides a Johnson figure of merit of 10.8 , which is among the highest reported values for fully passivated GaN HEMTs. A peak power-added efficiency of 37.5% with an output power of 1.25 W/mm and an associated gain of 9.7 dB was obtained by load-pull measurements at 40 GHz.
Autors: Downey, B.P.;Meyer, D.J.;Katzer, D.S.;Roussos, J.A.;Pan, M.;Gao, X.;
Appeared in: IEEE Electron Device Letters
Publication date: May 2014, volume: 35, issue:5, pages: 527 - 529
Publisher: IEEE
 
» In Situ Power Gating Efficiency Learner for Fine-Grained Self-Adaptive Power Gating
Abstract:
A low-power in situ learner circuit is presented to characterize the tradeoff between leakage saving and transition energy overhead in power gating (PG). A self-adaptive PG scheme is demonstrated that utilizes the learner circuit to adaptively invoke PG only when leakage saving is more than the transition energy overhead. A 130-nm test chip demonstrates functionality of the learner circuit and its application to adaptive PG under varying process, temperature, and idle signal pattern.
Autors: Trivedi, A.R.;Yueh, W.;Mukhopadhyay, S.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: May 2014, volume: 61, issue:5, pages: 344 - 348
Publisher: IEEE
 
» A 0.4-V, 90 350-MHz PLL With an Active Loop-Filter Charge Pump
Abstract:
A 0.4-V phase-locked loop (PLL) that has much improved power efficiency is realized in standard 65-nm CMOS. The PLL employs a novel ultralow-voltage charge pump that compensates current mismatch with an active loop filter and produces significantly reduced reference spurs. Its voltage-controlled oscillator (VCO) is designed with the body-bias technique and includes an automatic frequency calibration circuit that provides low VCO gain and wide tuning range. The PLL output frequency can be tuned from 90 to 350 MHz. At 350-MHz output, the PLL consumes 109 , which corresponds to the power efficiency of 0.31 mW/GHz.
Autors: Moon, J.;Choi, K.;Choi, W.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: May 2014, volume: 61, issue:5, pages: 319 - 323
Publisher: IEEE
 
» A 0.5-to-3 GHz Software-Defined Radio Receiver Using Discrete-Time RF Signal Processing
Abstract:
A software-defined radio (SDR) wireless receiver leveraging discrete-time (DT) RF signal processing is introduced. The proposed DT signal processor, which applies switched capacitor techniques to radio frequencies, achieves harmonic rejection, image rejection, and frequency translation simultaneously. A frequency tunable high-Q 2nd-order bandpass input impedance is synthesized by the DT RF signal processor, which enhances the front-end interference rejection and frequency selectivity. A proof-of-concept SDR receiver prototype, including a 65 nm LP CMOS chip and a custom designed board, is presented. The highly programmable chip allows independent control of individual block parameters and bias operating points for optimum performance under various signal scenarios. The 0.5-to-3 GHz SDR receiver achieves out-of-band IIP3 > 11 dBm, IIP2 > 46 dBm, uncalibrated 3rd and 5th order harmonic rejection exceeding 46 dB and 51 dB, respectively, and can handle up to 5 dBm blockers with less than 5 dB degradation in signal-to-noise ratio (SNR) when the blocker offset frequency is 10 times the signal bandwidth irrespective of the center frequency.
Autors: Chen, R.;Hashemi, H.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: May 2014, volume: 49, issue:5, pages: 1097 - 1111
Publisher: IEEE
 
» A 0.9–1.5 GHz Microstrip Antenna With Full Polarization Diversity and Frequency Agility
Abstract:
A microstrip antenna with frequency agility and polarization diversity is presented. Commercially available packaged RF microelectrical-mechanical (MEMS) single-pole double-throw (SPDT) devices are used with a novel feed network to provide four states of polarization control; linear-vertical, linear-horizontal, left-hand circular and right-handed circular. Also, hyper-abrupt silicon junction tuning diodes are used to tune the antenna center frequency from 0.9–1.5 GHz. The microstrip antenna is 1 in x 1 in, and is fabricated on a 4 in x 4 in commercial-grade dielectric laminate. To the authors' knowledge, this is the first demonstration of an antenna element with four polarization states across a tunable bandwidth of 1.4:1.
Autors: Ho, K.M.-J.;Rebeiz, G.M.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2014, volume: 62, issue:5, pages: 2398 - 2406
Publisher: IEEE
 
» A 1.2-MHz 5.8- Temperature-Compensated Relaxation Oscillator in 130-nm CMOS
Abstract:
This brief presents a low-power temperature-compensated relaxation oscillator in 130-nm CMOS for cubic millimeter wireless sensor node applications. An network is proposed for the oscillator, which introduces a zero in the transfer function, creating an additional degree of freedom in the step response used for frequency–temperature compensation. This approach uses conventional CMOS resistor and capacitor options and is fully integrated. The oscillator has a measured nominal frequency of 1.24 MHz with 1.0% variation from to 60 . It occupies an area of 0.02 and consumes 5.8 of active power with a leakage power of 440 pW.
Autors: Huang, K.;Wentzloff, D.D.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: May 2014, volume: 61, issue:5, pages: 334 - 338
Publisher: IEEE
 
» A 12 pJ/Pixel Analog-to-Information Converter Based 816 × 640 Pixel CMOS Image Sensor
Abstract:
Pub DtlAnalog-to-information converters (AICs) take advantage of the limited information bandwidth in high-frequency signals to improve the energy efficiency of front-end data converters. High-resolution image sensors often convey limited information due to the spatial redundancy between neighboring pixels. This paper proposes a mixed-signal AIC which compresses each nonoverlapping 4 × 4 pixel block in a 816 × 640 pixel prototype active-pixel sensor (APS) imager. It combines an energy-efficient charge-pump bit-image processor (BIP) with an area-efficient successive-approximation-register-single-slope (SAR-SS) hybrid analog-to-digital converter (ADC) via a charge-transfer-amplifier (CTA). The AIC is fully dynamic and consumes no static power. The ADC's capacitor array doubles as a computational device for parts of the compression algorithm which reduces its sampling rate by a factor of four. The compressed data contains direct edge information and can be decoded by a very simple receiver. The fabricated prototype consumes 12 pJ per pixel at 111 fps in the image compression mode and 48 pJ per pixel at 28.7 fps in raw data mode (9 b per pixel) under the same clock rate. To the best of our knowledge, this is the most energy-efficient compressive CMOS image sensor ever reported in the literature, thanks to the proposed AIC.
Autors: Chen, D.G.;Tang, F.;Law, M.-K.;Bermak, A.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: May 2014, volume: 49, issue:5, pages: 1210 - 1222
Publisher: IEEE
 
» A 12.5-Gb/s On-Chip Oscilloscope to Measure Eye Diagrams and Jitter Histograms of High-Speed Signals
Abstract:
This paper presents a 12.5-Gb/s on-chip oscilloscope (OCO) circuit to measure eye diagrams and jitter histograms of high-speed digital signals. The proposed circuit adopts a novel architecture to capture both single-ended and differential signals. In addition, it is capable of measuring the eye openings and jitter of the input signals without the need to construct the whole eye diagram which makes it a suitable candidate for eye-opening monitor circuits. An asynchronous sampling technique and an efficient algorithm are employed in this research to decrease the area of the OCO as well as its processing time. The proposed circuit is fabricated in a 65-nm CMOS technology and the measurement results show sub-picosecond resolution when the input signals consist of a 10-GHz clock signal and a 12.5-Gb/s pseudorandom binary sequence. The OCO circuit has a power consumption of 1.9 mW, and its core area is 40 60 .
Autors: Dehlaghi, B.;Magierowski, S.;Belostotski, L.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: May 2014, volume: 22, issue:5, pages: 1127 - 1137
Publisher: IEEE
 
» A 19 GHz CMOS Signal Generator for 77 GHz FMCW Radars
Abstract:
This letter presents a novel architecture of signal source suitable for the 77 GHz frequency-modulated continuous-wave (FMCW) radar transceiver. By using a conventional 19 GHz integer- phase-locked loop (PLL) with a frequency modulation loop, the required 19 GHz sinusoidal signal and 19–19.5 GHz FMCW frequency chirp can be generated simultaneously without excessive hardware overhead. Fabricated in a standard 65 nm CMOS process, the proposed circuit consumes a dc power of 68 mW from a supply voltage of 1.2 V.
Autors: Hsieh, Y.-K.;Lu, L.-H.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: May 2014, volume: 24, issue:5, pages: 339 - 341
Publisher: IEEE
 
» A 2-D Analytical Model for Double-Gate Tunnel FETs
Abstract:
This paper presents a 2-D analytic potential model for double-gate (DG) tunnel field effect transistors (TFETs) by solving the 2-D Poisson's equation. From the potential profile, the electric field is derived and then the drain current expression is extracted by analytically integrating the band-to-band tunneling generation rate over the tunneling region. The model well predicts the potential, subthreshold swing (SS), and transfer and output characteristics of DG TFETs. We analyze the dependence of the tunneling current on the device parameters by varying the gate oxide dielectric constant, gate oxide thickness, body thickness, channel length and channel material and also demonstrate its agreement with TCAD simulation results. The SS which describes the switching behavior of TFETs, is derived from the current expression. The comparisons show that the SS of our model well coincides with that of simulations.
Autors: Gholizadeh, M.;Hosseini, S.E.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: May 2014, volume: 61, issue:5, pages: 1494 - 1500
Publisher: IEEE
 
» A 2-D-Based Analytical Method for Calculating Permanent Magnetic Ring Bearings With Arbitrary Magnetization and Its Application to Optimal Bearing Design
Abstract:
This paper investigates the optimal design of passive permanent magnetic bearings in terms of maximum stiffness per magnet volume ratio. Examining the influence of design parameters on maximum material utilization, we present general conclusions regarding cross section dimension, type of magnetization, and magnetic pole number. Furthermore, we provide generalized design plots for selected configurations, which can be used for rapid dimensioning of bearings with adequate raw material utilization. The analytical computation method used for all calculations is based on the interaction energy of elementary magnetic dipoles and thus supports any kind of magnetization, including when strength and direction may vary within the cross section of the magnetic rings. Although the design problem is 3-D and the analytical method 2-D, the resulting error is negligible for most of the practical applications.
Autors: Marth, E.;Jungmayr, G.;Amrhein, W.;
Appeared in: IEEE Transactions on Magnetics
Publication date: May 2014, volume: 50, issue:5, pages: 1 - 8
Publisher: IEEE
 
» A 2.1-Channel Class-D Amplifier Exploited Coupling Virtual-Audio-Image to Enhance Stereo
Abstract:
This brief presents a novel 2.1-channel stereo-enhanced class-D audio amplifier to improve the quality of stereophonic sound in portable devices. By a way of cross coupling, the input audio signal from one channel can be amplified at the same time, with different gains in the two channels. The ratio of gains in the two channels can be adjusted by changing the resistance and then making the position of the virtual-audio-image change, which improves the stereo effect. The bass signals from different channels, which frequency range between 30 and 300 Hz, are superimposed and then amplified in the independent bass channel by using the Sallen–Key bandpass filter. A practical implementation in the SMIC 0.18- CMOS process has been done to validate the theoretical results. When a 200- sinusoidal signal at 1 kHz is applied in one channel and a dc signal applied in the other channel, the amplifier demonstrates a gain difference of 9.4 dB. The simulation and experiment results show that the amplifier can deliver 2.5 W 2 into 4- loads at 3.6-V supply in the left or right channel, with the total harmonic distortion plus noise (THD N) of less than 0.1%. The gain in the bass channel is up to 30 dB at 3.6-V power supply, with the THD N of about 0.05%.
Autors: Liu, L.;Deng, S.;Zhu, Z.;Yang, Y.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: May 2014, volume: 61, issue:5, pages: 324 - 328
Publisher: IEEE
 
» A 2.4 GHz Ultra-Low-Power Current-Reuse CG-LNA With Active -Boosting Technique
Abstract:
An ultra-low-power common-gate low noise amplifier (CG-LNA) for 2.4 GHz wireless sensor network (WSN) applications is proposed in this letter. The current-reuse and active -boosting techniques are utilized. The analysis, design method and measurement results are shown. An implemented prototype using 0.18 m CMOS technology is evaluated using on-wafer probing. Measurements also show a gain of 14.7 dB and an of 2 dBm at 2.44 GHz. The measured noise figure is 4.8 dB at 2.44 GHz. is below dB from 2–3 GHz. The proposed LNA consumes 0.58 mW from 1.8 V dc supply.
Autors: Li, Z.;Wang, Z.;Zhang, M.;Chen, L.;Wu, C.;Wang, Z.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: May 2014, volume: 24, issue:5, pages: 348 - 350
Publisher: IEEE
 
» A 2.7-mW 1.36–1.86-GHz LC-VCO With a FOM of 202 dBc/Hz Enabled by a 26%-Size-Reduced Nano-Particle-Magnetic-Enhanced Inductor
Abstract:
This paper reports the first LC voltage-controlled oscillator (LC-VCO) in CMOS utilizing a novel nontraditional compact inductor with integrated vertical nano particles magnetic core (Ni–Zn–Cu) to improve the figure-of-merit (FOM) of the VCO circuit. The new magnetic-enhanced inductor, fabricated in an integrated-circuit back-end using a CMOS-compatible process, improves inductance density ( -density) and quality factor ( -factor) up to 7 GHz. A 1.36–1.86-GHz VCO with a nano-ferrite-integrated inductor was fabricated in a 180-nm RF CMOS. Measurements show that the magnetic-cored inductor improves the -density and -factor by 49.8% and 59.2% at 1.8 GHz, respectively, while reducing the size by 26%. The VCO achieves reduced power consumption of 2.7 mW at a 1.8-V supply, low phase noise of less than , and at 100-kHz and 1-MHz frequencies offset, and a high FOM of 202 dBc/Hz. This prototype VCO demonstrates that the new vertical-nano-magnetic-cored inductor technology is a potential solution to high-performance low-cost compact RF systems-on-chip.
Autors: Cai, H.-L.;Yang, Y.;Qi, N.;Chen, X.;Tian, H.;Song, Z.;Xu, Y.;Zhou, C.-J.;Zhan, j.;Wang, A.;Chi, B.;Ren, T.-L.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: May 2014, volume: 62, issue:5, pages: 1221 - 1228
Publisher: IEEE
 
» A 56.4-to-63.4 GHz Multi-Rate All-Digital Fractional-N PLL for FMCW Radar Applications in 65 nm CMOS
Abstract:
A mm-wave digital transmitter based on a 60 GHz all-digital phase-locked loop (ADPLL) with wideband frequency modulation (FM) for FMCW radar applications is proposed. The fractional-N ADPLL employs a high-resolution 60 GHz digitally-controlled oscillator (DCO) and is capable of multi-rate two-point FM. It achieves a measured rms jitter of 590.2 fs, while the loop settles within 3 µs. The measured reference spur is only –74 dBc, the fractional spurs are below –62 dBc, with no other significant spurs. A closed-loop DCO gain linearization scheme realizes a GHz-level triangular chirp across multiple DCO tuning banks with a measured frequency error (i.e., nonlinearity) in the FMCW ramp of only 117 kHz rms for a 62 GHz carrier with 1.22 GHz bandwidth. The synthesizer is transformer-coupled to a 3-stage neutralized power amplifier (PA) that delivers +5 dBm to a 50 Ω load. Implemented in 65 nm CMOS, the transmitter prototype (including PA) consumes 89 mW from a 1.2 V supply.
Autors: Wu, W.;Staszewski, R.B.;Long, J.R.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: May 2014, volume: 49, issue:5, pages: 1081 - 1096
Publisher: IEEE
 
» A 6-bit 1-GS/s Two-Step SAR ADC in 40-nm CMOS
Abstract:
This brief presents a single-channel two-step successive approximation register (SAR) analog-to-digital converter (ADC) using a source follower as an interstage residue amplifier. An asynchronous SAR ADC with two-step timing can effectively allocate the bit-resolving procedure into the whole clock period and eliminate a dedicated duty-cycle clock generator. The arbitrary weight capacitor array technique is utilized to tolerate offset mismatch between the coarse and fine stages. The level-shift technique is used to accelerate the comparator. The ADC in 40-nm CMOS obtains 5.6 and 4.9 effective numbers of bits at Nyquist with the conversion rate of 800 MS/s and 1 GS/s, respectively. It consumes 5.3 mW at 1 GS/s and achieves a figure of merit of 180 fJ/conversion-step. The core circuit occupies an area of 0.009 .
Autors: Tai, H.;Tsai, C.;Tsai, P.;Chen, H.;Chen, H.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: May 2014, volume: 61, issue:5, pages: 339 - 343
Publisher: IEEE
 
» A 70 dB DR 10 b 0-to-80 MS/s Current-Integrating SAR ADC With Adaptive Dynamic Range
Abstract:
A charge-domain SAR ADC is presented which integrates the current of a variable-gain transconductor on its sampling capacitor, rather than being driven by a power hungry voltage buffer. The sampling circuit uses nonlinear MOS capacitors as sampling capacitor for passive amplification to relax the comparator noise requirements without compromising linearity. The prototype in 40 nm low power CMOS process consists of a 1.1–17.6 mS transconductor, combined with a 10 b 0–80 MS/s charge-sharing SAR ADC. It achieves 70 dB DR while consuming less than 5.45 mA from a 1.1 V supply and achieves a peak SNDR of 56.85 dB at 40 MS/s.
Autors: Malki, B.;Yamamoto, T.;Verbruggen, B.;Wambacq, P.;Craninckx, J.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: May 2014, volume: 49, issue:5, pages: 1173 - 1183
Publisher: IEEE
 
» A 780–950 MHz, 64–146 µW Power-Scalable Synchronized-Switching OOK Receiver for Wireless Event-Driven Applications
Abstract:
An on/off keying receiver has been designed in 90 nm CMOS for low-power event-driven applications. Thanks to the synchronized-switching technique and power-efficient RF gain stages, this receiver achieves 86 dBm sensitivity (10 bit error rate) at 10 kbps while consuming 123 µW from a 1 V supply. The receiver is highly scalable in data rates from 1 kbps at 64 µW to 100 kbps at 146 µW power consumption. The center frequency of the receiver can be also programmed from 780 to 950 MHz, covering different sub-GHz bands worldwide. The receiver is fully integrated, although an external SAW filter can be added for better selectivity.
Autors: Huang, X.;Harpe, P.;Dolmans, G.;de Groot, H.;Long, J.R.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: May 2014, volume: 49, issue:5, pages: 1135 - 1147
Publisher: IEEE
 
» A bisected pupil for studying single-molecule orientational dynamics and its application to three-dimensional super-resolution microscopy
Abstract:
A phase mask design that we term a “bisected pupil” (BSP) provides several advantages for single-molecule optical imaging. When using the BSP with a dual-polarization optical Fourier processing system, both the position and dipole orientation of individual fluorescent molecules may be measured from a single camera image. In the context of single-molecule super-resolution microscopy, this technique permits one to diagnose, and subsequently to remove imaging artifacts resulting from orientation-induced localization errors. If the molecules labeling a structure are rotationally mobile, thus mitigating dipole orientation errors, this technique enables super-resolution imaging in three dimensions. We present simulations and experimental verification.
Autors: Backer, Adam S.;Backlund, Mikael P.;von Diezmann, Alexander R.;Sahl, Steffen J.;Moerner, W.E.;
Appeared in: Applied Physics Letters
Publication date: May 2014, volume: 104, issue:19, pages: 193701 - 193701-5
Publisher: IEEE
 
» A Blind Likelihood-Based Approach for OFDM Spectrum Sensing in the Presence of I/Q Imbalance
Abstract:
We investigate the spectrum sensing problem in orthogonal frequency-division multiplexing-based cognitive radio networks under I/Q imbalance. We start by deriving the likelihood ratio test in the presence of I/Q imbalance at the analog front-ends of both the primary and secondary users. In addition, we derive closed-form expressions for the probabilities of detection and false alarm and the receiver operating characteristics and examine their dependence on both transmit and receive I/Q imbalance levels. Furthermore, we compare the performance of the likelihood ratio test with that of the energy detector and demonstrate the superiority of the former over the latter. Next, we generalize our analysis to the blind case where we derive simple closed-form expressions for the generalized likelihood ratio test and its false alarm probability as a function of the received signal only, i.e. without requiring any knowledge of the primary-to-secondary channel response, noise statistics, or I/Q imbalance parameters. Our results demonstrate that the correlation properties of the primary user's signal induced by transmit I/Q imbalance are signal features that can be exploited in a blind fashion at the secondary user to enhance the detection probability significantly compared to the conventional energy detector.
Autors: ElSamadouny, Ahmed;Gomaa, Ahmad;Al-Dhahir, Naofal;
Appeared in: IEEE Transactions on Communications
Publication date: May 2014, volume: 62, issue:5, pages: 1418 - 1430
Publisher: IEEE
 
» A Block-Wise Autoregression-Based Deinterlacing Algorithm
Abstract:
This paper introduces an autoregression-based single-field deinterlacing algorithm. The proposed algorithm provides a block-wise autoregression mechanism that considers mutual influence between the missing high-resolution pixels and the given interlaced, low-resolution pixels in a slip window. This method is compared with other benchmark methods in terms of PSNR, implementing speed, and subjective performance. It is found that, with the proposed algorithm, common artifacts such as serration, line crawl, and flicker are significantly reduced.
Autors: Wang, J.;Jeon, G.;Jeong, J.;
Appeared in: Journal of Display Technology
Publication date: May 2014, volume: 10, issue:5, pages: 414 - 419
Publisher: IEEE
 
» A Brain Surgery Simulator
Abstract:
A proposed real-time neurosurgery simulator handles skull drilling and surgical interaction with the brain. This involves the development and combination of areas such as collision handling, haptic rendering, physical simulation, and volumetric visualization. The simulator's input data comes from computed-tomography and magnetic-resonance-imaging images of the patients. Collision detection for drilling uses only density data; collision detection for interaction with the brain is based on uniform spatial subdivision of a tetrahedral mesh. To take advantage of all the information, the simulator employs visualization methods such as volumetric isosurfaces and deformable volume rendering.
Autors: Echegaray, Goretti;Herrera, Imanol;Aguinaga, Iker;Buchart, Carlos;Borro, Diego;
Appeared in: IEEE Computer Graphics and Applications
Publication date: May 2014, volume: 34, issue:3, pages: 12 - 18
Publisher: IEEE
 
» A Bregman Matrix and the Gradient of Mutual Information for Vector Poisson and Gaussian Channels
Abstract:
A generalization of Bregman divergence is developed and utilized to unify vector Poisson and Gaussian channel models, from the perspective of the gradient of mutual information. The gradient is with respect to the measurement matrix in a compressive-sensing setting, and mutual information is considered for signal recovery and classification. Existing gradient-of-mutual-information results for scalar Poisson models are recovered as special cases, as are known results for the vector Gaussian model. The Bregman-divergence generalization yields a Bregman matrix, and this matrix induces numerous matrix-valued metrics. The metrics associated with the Bregman matrix are detailed, as are its other properties. The Bregman matrix is also utilized to connect the relative entropy and mismatched minimum mean squared error. Two applications are considered: 1) compressive sensing with a Poisson measurement model and 2) compressive topic modeling for analysis of a document corpora (word-count data). In both of these settings, we use the developed theory to optimize the compressive measurement matrix, for signal recovery and classification.
Autors: Wang, L.;Carlson, D.E.;Rodrigues, M.R.D.;Calderbank, R.;Carin, L.;
Appeared in: IEEE Transactions on Information Theory
Publication date: May 2014, volume: 60, issue:5, pages: 2611 - 2629
Publisher: IEEE
 
» A Brief History of Tissue Models For Cardiac Electrophysiology
Abstract:
The last four decades have produced a number of significant advances in the developments of computer models to simulate and investigate the electrical activity of cardiac tissue. The tissue descriptions that underlie these simulations have been built from a combination of clever insight and careful comparison with measured data at multiple scales. Tissue models have not only led to greater insights into the mechanisms of life-threatening arrhythmias but have been used to engineer new therapies to treat the consequences of cardiac disease. This paper is a look back at the early years in the cardiac modeling and the challenges facing the field as models move toward the clinic.
Autors: Henriquez, C.S.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: May 2014, volume: 61, issue:5, pages: 1457 - 1465
Publisher: IEEE
 
» A Broadband Radar Absorber Based on Perforated Magnetic Polymer Composites Embedded With FSS
Abstract:
This paper presents a design method of broadband radar absorber (RA) combining together the features of frequency selective surfaces (FSSs), subwavelength hole array, and magnetic absorbing sheets. The absorber is constructed of a periodic array of square conducting patches embedded into a magnetic absorbing substrate perforated with circular hole arrays and backed by a metal ground. The absorption characteristics of the magnetic absorbing substrate are tuned and improved by means of perforating holes and embedding FSSs. After optimizing the dimensions of the holes and FSSs, the RA with a thickness of 2.4 mm achieves a reflection coefficient less than from 6.3 to 17.3 GHz, which is nearly 3.6 times the bandwidth of the magnetic absorbing substrate. Meanwhile, the weight of the RA decreases by 15% due to the hole perforation, and the reflection coefficient is insensitive to incident angle from 0 to 30 for both TE and TM polarizations.
Autors: Zhang, L.;Zhou, P.;Zhang, H.;Lu, L.;Zhang, G.;Chen, H.;Lu, H.;Xie, J.;Deng, L.;
Appeared in: IEEE Transactions on Magnetics
Publication date: May 2014, volume: 50, issue:5, pages: 1 - 5
Publisher: IEEE
 
» A calibrated graphene-based chemi-sensor for sub parts-per-million NO2 detection operating at room temperature
Abstract:
Here, we present a room temperature operating chemi-sensor based on a graphene film that shows sensitivity to NO2 up to a 50 parts-per-billion (ppb) with extremely limited interference from relative humidity and can be also calibrated in a sub-parts-per-million (ppm) range with a response and recovery time of few seconds. The device has been fabricated using as active material, a solution of graphene nanosheets suspended in N-methyl-pyrrolidone drop casted on an alumina substrate with gold interdigitated electrodes. The derivative of the device response is found to be univocally correlated to NO2 concentrations from 100 ppb up to 1000 ppb and the sensor can therefore be calibrated in this same range.
Autors: Ricciardella, F.;Massera, E.;Polichetti, T.;Miglietta, M.L.;Di Francia, G.;
Appeared in: Applied Physics Letters
Publication date: May 2014, volume: 104, issue:18, pages: 183502 - 183502-5
Publisher: IEEE
 
» A Case Study on a Capsule Robot in the Gastrointestinal Tract to Teach Robot Programming and Navigation
Abstract:
Pub DtlDespite the increasing importance of robotics, there is a significant challenge involved in teaching this to undergraduate students in biomedical engineering (BME) and other related disciplines in which robotics techniques could be readily applied. This paper addresses this challenge through the development and pilot testing of a bio-microrobotics case study that can be integrated into curricula in BME, electrical and computer engineering (ECE), and other disciplines. This case study is based on the existing technology of wireless capsule endoscopy and centered on a “grand challenge” of building a capsule robot to navigate the human gastrointestinal tract to detect abnormality or to destroy malignant tissues. First, a conceptual design example for building such a capsule robot is presented, followed by a laboratory module that demonstrates robot navigation techniques using Webots simulation. The case study introduces robotic technologies, including robot building components, operating modes, and behavior-based programming, and students experience robot simulation in the laboratory module. The case study developed was pilot tested in three BME and ECE courses at the authors' institution. The evaluation results demonstrate the effectiveness of the case study in enhancing students' understanding of robotics, interdisciplinary skills, and critical thinking. The case study is shown to support challenge-based learning, which promotes adaptive expertise through rapid knowledge building and innovation.
Autors: Guo, Y.;Zhang, S.;Ritter, A.;Man, H.;
Appeared in: IEEE Transactions on Education
Publication date: May 2014, volume: 57, issue:2, pages: 112 - 121
Publisher: IEEE
 
» A Centimeter Resolution, 10 m Range CMOS Impulse Radio Radar for Human Motion Monitoring
Abstract:
Pub DtlA single-chip impulse radio radar transceiver that enables high-resolution reception with enhanced signal to noise ratio (SNR) is proposed. The radar transceiver, consisting of a spectrum adjustable transmitter and a 100-ps resolution 4-channel sampling receiver, successfully demonstrates in/outdoor human walk tracing, stride-rate, and respiration measurements. The 4-channel sampling receiver, which is robust against pulse distortion, utilizes track and hold samplers and integrators while sharing a single low noise amplifier. By adopting embedded control logic, the sampling receiver achieves control flexibility as well as improved performance. A repetitive reception mode can proportionally increase the SNR of the receive pulse at the cost of a longer pulse acquisition time. DC offset and low-frequency coherent noise problems caused by on-board control clock signals are resolved with the radar architecture. The single chip radar transceiver is fabricated in a 130-nm CMOS technology occupying a chip area of 3.27 mm . The measured results show that echo pulses are recovered with a centimeter range resolution while consuming 80 mA from a supply voltage of 1.2 V.
Autors: Park, P.;Kim, S.;Woo, S.;Kim, C.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: May 2014, volume: 49, issue:5, pages: 1125 - 1134
Publisher: IEEE
 
» A Closed-Form Expression of Optimal Time for Two-Way Relay Using DF MABC Protocol
Abstract:
In this paper, we propose the optimal time allocation for two-way relay using decode-and-forward (DF) multiple access broadcast (MABC) protocol. We analytically determine the optimal transmit time durations for the first and the second time slots, which maximize the achievable sum rate under a sum time constraint for a given squared magnitude of the channel coefficients and transmit power values. Numerical results show that the achievable sum rate of the optimal time allocation is greater than or equal to that of the equal time allocation.
Autors: Shim, Yeonggyu;Park, Hyuncheol;
Appeared in: IEEE Communications Letters
Publication date: May 2014, volume: 18, issue:5, pages: 721 - 724
Publisher: IEEE
 
» A Cockcroft–Walton Voltage Multiplier Fed by a Three-Phase-to-Single-Phase Matrix Converter With PFC
Abstract:
This paper proposes a single-stage three-phase-to-single-phase current-fed high step-up ac–dc matrix converter. The proposed converter inserts a boost-type matrix converter, which is formed by three boost inductors and six bidirectional switches, between a three-phase ac source and a Cockcroft–Walton voltage multiplier (CWVM). By using this topology associated with power factor correction technique, the proposed converter not only achieves almost unity power factor and sinusoidal input currents with low distortion but also obtains high voltage gain at the output end. Moreover, the matrix converter generates an adjustable-frequency and adjustable-amplitude current, which injects into the CWVM to regulate the dc output voltage and smooth its ripple. With this flexible injection current, the performance of the proposed converter is superior to the conventional CWVM, which is usually energized by a single-phase ac source. The operation principle, control strategy, and design considerations of the proposed converter are detailed in this paper. Finally, simulation and experimental results demonstrate the claims and validity of the proposed converter.
Autors: Young, C.;Chen, H.;Chen, M.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: May 2014, volume: 50, issue:3, pages: 1994 - 2004
Publisher: IEEE
 
» A Combined Ab Initio and Experimental Study on the Nature of Conductive Filaments in Resistive Random Access Memory
Abstract:
Through ab initio calculations, we propose that the conductive filaments in resistive random access memories are due to suboxides, possibly tetragonal, where . The electroforming process is initiated by a continuous supply of oxygen Frenkel defect pairs through an electrochemical process. The accumulation of oxygen vacancies leads to metallic suboxide phases, which remain conductive even as ultranarrow 1- filaments embedded in an insulating matrix. Our experiments further show that the filaments remain as major leakage paths even in the OFF-state. Moreover, thermal heating may increase the OFF-state resistance, implying that there are oxygen interstitials left in the oxide layer, which may recombine with the oxygen vacancies in the filaments at high temperature.
Autors: Xue, K.;Traore, B.;Blaise, P.;Fonseca, L.R.C.;Vianello, E.;Molas, G.;De Salvo, B.;Ghibaudo, G.;Magyari-Kope, B.;Nishi, Y.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: May 2014, volume: 61, issue:5, pages: 1394 - 1402
Publisher: IEEE
 
» A Combined Homogeneous Domination and Sign Function Approach to Output-Feedback Stabilization of Stochastic High-Order Nonlinear Systems
Abstract:
For a class of stochastic high-order nonlinear systems, by introducing the combined homogeneous domination and sign function design approach, this technical note solves the problem of output-feedback control under the weaker high-order and nonlinear growth conditions.
Autors: Xie, X.-J.;Duan, N.;Zhao, C.-R.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: May 2014, volume: 59, issue:5, pages: 1303 - 1309
Publisher: IEEE
 
» A compact, multichannel, and low noise arbitrary waveform generator
Abstract:
A new type of high functionality, fast, compact, and easy programmable arbitrary waveform generator for low noise physical measurements is presented. The generator provides 7 fast differential waveform channels with a maximum bandwidth up to 200 MHz frequency. There are 6 fast pulse generators on the generator board with 78 ps time resolution in both duration and delay, 3 of them with amplitude control. The arbitrary waveform generator is additionally equipped with two auxiliary slow 16 bit analog-to-digital converters and four 16 bit digital-to-analog converters for low frequency applications. Electromagnetic shields are introduced to the power supply, digital, and analog compartments and with a proper filter design perform more than 110 dB digital noise isolation to the output signals. All the output channels of the board have 50 Ω SubMiniature version A termination. The generator board is suitable for use as a part of a high sensitive physical equipment, e.g., fast read out and manipulation of nuclear magnetic resonance or superconducting quantum systems and any other application, which requires electromagnetic interference free fast pulse and arbitrary waveform generation.
Autors: Govorkov, S.;Ivanov, B.I.;Il'ichev, E.;Meyer, H.-G.;
Appeared in: Review of Scientific Instruments
Publication date: May 2014, volume: 85, issue:5, pages: 054702 - 054702-5
Publisher: IEEE
 
» A Comparative Study on the Impacts of Interface Traps on Tunneling FET and MOSFET
Abstract:
In this paper, the impacts of interface traps on tunneling FET (TFET) are examined in terms of different trap energies and distributions, charge neutrality level (CNL), and effects of random trap fluctuation, in comparison with MOSFET. It is found that the shifts and subthreshold swing (SS) degradation induced by interface traps in TFET and MOSFET have the same trends, but the impacts on are different because of the novel conduction mechanism of TFETs when compared with MOSFETs. Moreover, nTFET is intrinsically more immune (or susceptible) to shift induced by acceptor- (or donor-) type interface traps than nMOSFET. Therefore, reducing the potential degradation induced by the interface traps can be achieved by optimizing the position of CNL. The results indicate that nTFET is more immune to the shift than nMOSFET with CNL below a critical energy. In addition, the trap-induced SS degradation of TFET is severer than MOSFET in electrostatics. Moreover, it is found that the , , and fluctuations in nMOSFET and nTFET are also dependent on the position of CNL. With CNL below the critical energy, the fluctuation and fluctuation of nTFET are smaller than those of nMOSFET. The- results are helpful for the interface optimization of TFETs.
Autors: Qiu, Y.;Wang, R.;Huang, Q.;Huang, R.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: May 2014, volume: 61, issue:5, pages: 1284 - 1291
Publisher: IEEE
 
» A Comparison of Two Excitation Modes for MEMS Electrothermal Displacement Sensors
Abstract:
MEMS electrothermal displacement sensors can be operated in constant current (CC) or constant voltage (CV) excitation modes. The CV mode is more commonly used. However, there have been reports that the CC excitation mode may lead to a larger measured signal, and thus, it may be a better choice than the CV mode. In this letter, we present an analytic comparison of the two methods, and show that from a signal-to-noise-ratio point of view, benefits of operating a sensor in CC mode are only marginal. The analytical investigation is supported by experiments performed on sensors integrated in a SOI-MEMS nanopositioner with low noise read out circuits, which leads to displacement resolution for both excitation modes.
Autors: Mohammadi, A.;Moheimani, S.O.R.;Yuce, M.R.;
Appeared in: IEEE Electron Device Letters
Publication date: May 2014, volume: 35, issue:5, pages: 584 - 586
Publisher: IEEE
 
» A Comprehensive Assessment of Gait Accelerometry Signals in Time, Frequency and Time-Frequency Domains
Abstract:
Gait accelerometry is a promising tool to assess human walking and reveal deteriorating gait characteristics in patients and can be a rich source of clinically relevant information about functional declines in older adults. Therefore, in this paper, we present a comprehensive set of signal features that may be used to extract clinically valuable information from gait accelerometry signals. To achieve our goal, we collected tri-axial gait accelerometry signals from 35 adults 65 years of age and older. Fourteen subjects were healthy controls, 10 participants were diagnosed with Parkinson's disease, and 11 participants were diagnosed with peripheral neuropathy. The data were collected while the participants walked on a treadmill at a preferred walking speed. Accelerometer signal features in time, frequency and time-frequency domains were extracted. The results of our analysis showed that some of the extracted features were able to differentiate between healthy and clinical populations. Signal features in all three domains were able to emphasize variability among different groups, and also revealed valuable information about variability of the signals between anterior–posterior, mediolateral, and vertical directions within subjects. The current results imply that the proposed signal features can be valuable tools for the analysis of gait accelerometry data and should be utilized in future studies.
Autors: Sejdic, E.;Lowry, K.A.;Bellanca, J.;Redfern, M.S.;Brach, J.S.;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: May 2014, volume: 22, issue:3, pages: 603 - 612
Publisher: IEEE
 
» A Comprehensive Comparison of Data Stability Enhancement Techniques With Novel Nanoscale SRAM Cells Under Parameter Fluctuations
Abstract:
Conventional Static Random Access Memory (SRAM) cells suffer from an intrinsic data instability problem due to directly-accessed data storage nodes during a read operation. Noise margins of memory cells further shrink with increasing variability and decreasing power supply voltage in scaled CMOS technologies. A seven-transistor (7T), an eight-transistor (8T), a nine-transistor (9T), and 3 conventional six-transistor (6T) memory circuits are characterized for layout area, data stability, write voltage margin, data access speed, active power consumption, idle mode leakage currents, and minimum power supply voltage in this paper. A comprehensive electrical performance metric is evaluated to compare the memory cells considering process parameter and supply voltage fluctuations. The triple-threshold-voltage 8T and 9T SRAM cells provide up to 2.5x stronger data stability and 765.9x higher overall electrical quality as compared to the traditional 6T SRAM cells in a TSMC 65 nm CMOS technology.
Autors: Zhu, H.;Kursun, V.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: May 2014, volume: 61, issue:5, pages: 1473 - 1484
Publisher: IEEE
 
» A Construction of New Quantum MDS Codes
Abstract:
It has been a great challenge to construct new quantum maximum-distance-separable (MDS) codes. In particular, it is very hard to construct the quantum MDS codes with relatively large minimum distance. So far, except for some sparse lengths, all known -ary quantum MDS codes have minimum distance . In this paper, we provide a construction of the quantum MDS codes with minimum distance . In particular, we show the existence of the -ary quantum MDS codes with length and minimum distance for any (this result extends those given in [10], [12], and [13]); and with length and minimum distance for any if . Our method is through Hermitian self-orthogonal codes. The main idea of constructing the Hermitian self-orthogonal codes is based on the solvability in of a system of homogenous equations over .
Autors: Jin, L.;Xing, C.;
Appeared in: IEEE Transactions on Information Theory
Publication date: May 2014, volume: 60, issue:5, pages: 2921 - 2925
Publisher: IEEE
 
» A continuum model with a percolation threshold and tunneling-assisted interfacial conductivity for carbon nanotube-based nanocomposites
Abstract:
A continuum model that possesses several desirable features of the electrical conduction process in carbon-nanotube (CNT) based nanocomposites is developed. Three basic elements are included: (i) percolation threshold, (ii) interface effects, and (iii) tunneling-assisted interfacial conductivity. We approach the first one through the selection of an effective medium theory. We approach the second one by the introduction of a diminishing layer of interface with an interfacial conductivity to build a "thinly coated" CNT. The third one is introduced through the observation that interface conductivity can be enhanced by electron tunneling which in turn can be facilitated with the formation of CNT networks. We treat this last issue in a continuum fashion by taking the network formation as a statistical process that can be represented by Cauchy's probability density function. The outcome is a simple and yet widely useful model that can simultaneously capture all these fundamental characteristics. It is demonstrated that, without considering the interface effect, the predicted conductivity would be too high, and that, without accounting for the additional contribution from the tunneling-assisted interfacial conductivity, the predicted conductivity beyond the percolation threshold would be too low. It is with the consideration of all three elements that the theory can fully account for the experimentally measured data. We further use the developed model to demonstrate that, despite the anisotropy of the intrinsic CNT conductivity, it is its axial component along the CNT direction that dominates the overall conductivity. This theory is also proved that, even with a totally insulating matrix, it is still capable of delivering non-zero conductivity beyond the percolation threshold.
Autors: Wang, Yang;Weng, George J.;Meguid, Shaker A.;Hamouda, Abdel Magid;
Appeared in: Journal of Applied Physics
Publication date: May 2014, volume: 115, issue:19, pages: 193706 - 193706-9
Publisher: IEEE
 
» A Coupled Resonator Decoupling Network for Two-Element Compact Antenna Arrays in Mobile Terminals
Abstract:
A new concept for decoupling two coupled antenna elements in a broad band using a coupled resonator decoupling network (CRDN) is proposed for the first time. A synthesis and design theory of a CRDN is presented. Based on the admittance parameters of a given antenna array, a set of required rational functions and, consequently, the coupling matrix for a second-order decoupling network is obtained analytically. To prove the concept, two prototypes using microstrip resonators are designed and experimentally studied. Measurement results have demonstrated that an isolation improvement of more than 10 dB can be achieved within more than 15% bandwidth in both examples. The benefits of using a CRDN for different levels of isolation in a MIMO terminal are investigated through experiments and simulations. The results have shown that, as compared to the existing decoupling scheme using a lumped element, the proposed CRDN scheme can significantly increase the radiation efficiency, reduce the correlation, improve the channel capacity, and above all enhance the throughput of a MIMO terminal. The technique is general and can be applied to both symmetric and asymmetric arrays.
Autors: Zhao, L.;Yeung, L.K.;Wu, K.-L.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2014, volume: 62, issue:5, pages: 2767 - 2776
Publisher: IEEE
 
» A Customer Churn Prediction Model in Telecom Industry Using Boosting
Abstract:
With the rapid growth of digital systems and associated information technologies, there is an emerging trend in the global economy to build digital customer relationship management (CRM) systems. This trend is more obvious in the telecommunications industry, where companies become increasingly digitalized. Customer churn prediction is a main feature of in modern telecomcommunication CRM systems. This research conducts a real-world study on customer churn prediction and proposes the use of boosting to enhance a customer churn prediction model. Unlike most research that uses boosting as a method to boost the accuracy of a given basis learner, this paper tries to separate customers into two clusters based on the weight assigned by the boosting algorithm. As a result, a higher risk customer cluster has been identified. Logistic regression is used in this research as a basis learner, and a churn prediction model is built on each cluster, respectively. The result is compared with a single logistic regression model. Experimental evaluation reveals that boosting also provides a good separation of churn data; thus, boosting is suggested for churn prediction analysis.
Autors: Lu, N.;Lin, H.;Lu, J.;Zhang, G.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: May 2014, volume: 10, issue:2, pages: 1659 - 1665
Publisher: IEEE
 
» A Denial of Service Attack to UMTS Networks Using SIM-Less Devices
Abstract:
One of the fundamental security elements in cellular networks is the authentication procedure performed by means of the Subscriber Identity Module that is required to grant access to network services and hence protect the network from unauthorized usage. Nonetheless, in this work we present a new kind of denial of service attack based on properly crafted SIM-less devices that, without any kind of authentication and by exploiting some specific features and performance bottlenecks of the UMTS network attachment process, are potentially capable of introducing significant service degradation up to disrupting large sections of the cellular network coverage. The knowledge of this attack can be exploited by several applications both in security and in network equipment manufacturing sectors.
Autors: Merlo, A.;Migliardi, M.;Gobbo, N.;Palmieri, F.;Castiglione, A.;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: May 2014, volume: 11, issue:3, pages: 280 - 291
Publisher: IEEE
 
» A Dimmable LED Driver Based on Current Balancing Transformer With Magnetizing Energy Recycling Considered
Abstract:
In this paper, a dimmable LED current balancing driver is presented, which is based on the current balancing transformer with magnetizing inductance energy recycling considered. Such a driver has the main power stage constructed by one Zeta type converter. Hence, the energy stored in the magnetizing inductance can be released to the energy-transferring capacitor, thereby causing energy recycling to be achieved. In this paper, a detailed illustration of the basic operating principles of the proposed LED driver is first given, and finally some experimental results are provided to demonstrate its effectiveness.
Autors: Hwu, K.I.;Tu, W.C.;Hong, M.J.;
Appeared in: Journal of Display Technology
Publication date: May 2014, volume: 10, issue:5, pages: 388 - 395
Publisher: IEEE
 
» A Distributed Auction-Based Algorithm for the Nonconvex Economic Dispatch Problem
Abstract:
This paper presents a distributed algorithm based on auction techniques and consensus protocols to solve the nonconvex economic dispatch problem. The optimization problem of the nonconvex economic dispatch includes several constraints such as valve-point loading effect, multiple fuel option, and prohibited operating zones. Each generating unit locally evaluates quantities used as bids in the auction mechanism. These units send their bids to their neighbors in a communication graph that supports the power system and which provides the required information flow. A consensus procedure is used to share the bids among the network agents and resolves the auction. As a result, the power distribution of generating units is updated and the generation cost is minimized. The effectiveness of this approach is demonstrated by simulations on standard test systems.
Autors: Binetti, G.;Davoudi, A.;Naso, D.;Turchiano, B.;Lewis, F.L.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: May 2014, volume: 10, issue:2, pages: 1124 - 1132
Publisher: IEEE
 
» A Distributed Consensus Algorithm for Decision Making in Service-Oriented Internet of Things
Abstract:
In a service-oriented Internet of things (IoT) deployment, it is difficult to make consensus decisions for services at different IoT edge nodes where available information might be insufficient or overloaded. Existing statistical methods attempt to resolve the inconsistency, which requires adequate information to make decisions. Distributed consensus decision making (CDM) methods can provide an efficient and reliable means of synthesizing information by using a wider range of information than existing statistical methods. In this paper, we first discuss service composition for the IoT by minimizing the multi-parameter dependent matching value. Subsequently, a cluster-based distributed algorithm is proposed, whereby consensuses are first calculated locally and subsequently combined in an iterative fashion to reach global consensus. The distributed consensus method improves the robustness and trustiness of the decision process.
Autors: Li, S.;Oikonomou, G.;Tryfonas, T.;Chen, T.M.;Xu, L.D.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: May 2014, volume: 10, issue:2, pages: 1461 - 1468
Publisher: IEEE
 
» A Distributed Fault Detection System Based on IWSN for Machine Condition Monitoring
Abstract:
This paper introduces a novel framework for industrial wireless sensor networks (IWSNs) used for machine condition monitoring (MCM). Our approach enables the use of state-of-the-art computationally intensive classifiers in computationally weak sensor network nodes. The key idea is to split data acquisition, classifier building and training, and the operation phase, between different units. Computationally demanding processing is carried out in the central unit, while other tasks are distributed to the sensor nodes using over-the-air programming. The system is autonomously trained on the healthy state of a machine and then monitors a change in behavior which indicates a faulty state. Thanks to one-class classification, there is no need to introduce the faulty state of the machine in the training phase. We extend the diagnostic capability of the system using dynamic changes in the data acquisition and classification parts of the program in the sensor nodes. This enables the system to react to ambiguous machine states by temporarily changing the diagnostic focus. Compressing the information in the individual sensor nodes provided by in-node classification allows us to transmit only the classification result, instead of full signal waveforms. This enables the MCM system to be deployed with a large number of nodes, even with high sampling rates. The proposed concept was evaluated in IRIS IWSN by means of a rotary machine simulator.
Autors: Neuzil, J.;Kreibich, O.;Smid, R.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: May 2014, volume: 10, issue:2, pages: 1118 - 1123
Publisher: IEEE
 
» A Dual-Broadband Circularly Polarized Slot Antenna for WLAN Applications
Abstract:
A novel dual-band, circularly polarized slot antenna with broadband characteristics in both axial ratio and impedance is developed. The radiations of antenna exhibit a left-hand circular polarization in the direction and a right-hand circular polarization in the opposite direction at both the lower and upper bands. The measured impedance bandwidths are 55.33% (1.83–3.23 GHz) and 20.98% (4.99–6.16 GHz) while the axial ratio bandwidths are 32.14% (1.88–2.60 GHz) and 31.49% (4.95–6.80 GHz) at the lower and upper bands, respectively. In comparison to the recent works, the proposed antenna has a simpler structure, a more compact size, wider impedance bandwidths, and wider axial ratio bandwidths.
Autors: Weng, W.-C.;Sze, J.-Y.;Chen, C.-F.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2014, volume: 62, issue:5, pages: 2837 - 2841
Publisher: IEEE
 
» A Dual-Wavelength Fiber Ring Laser Incorporating an Injection-Coupled Optoelectronic Oscillator and Its Application to Transverse Load Sensing
Abstract:
A novel configuration for a dual-wavelength fiber ring laser with improved lasing stability realized through the use of an injection-coupled optoelectronic oscillator (OEO) is proposed and demonstrated, and its application to transverse load sensing is studied. The OEO-coupled dual-wavelength laser has two mutually coupled loops: the fiber ring loop and the OEO loop. In the fiber ring loop, a polarization-maintaining phase-shifted fiber Bragg grating is incorporated to generate two optical wavelengths with the wavelength spacing determined by the birefringence of the polarization-maintaining (PM) fiber. In the OEO loop, a microwave signal with its frequency also determined by the birefringence of the PM fiber is generated, which is fed into the fiber ring loop to injection lock the dual wavelengths. Due to the injection locking, a very stable dual-wavelength operation is established. The use of the dual wavelengths for high-resolution and high-speed transverse load sensing is then implemented. The sensitivity of the transverse load sensor is measured as high as +9.7573 and -9.7350 GHz/(N/mm), along the fast and slow axes, respectively. The high frequency purity and stability of the generated microwave signal permits very reliable and high accuracy measurement and the microwave frequency interrogation allows the system to operate at an ultra-high speed.
Autors: Fanqi Kong;Romeira, B.;Jiejun Zhang;Wangzhe Li;Jianping Yao;
Appeared in: Journal of Lightwave Technology
Publication date: May 2014, volume: 32, issue:9, pages: 1784 - 1793
Publisher: IEEE
 
» A Fast Analysis of Scattering From Large-Scale Finite Periodic Microstrip Patch Arrays Arranged on a Non-Orthogonal Lattice Using Sub-Entire Domain Basis Functions
Abstract:
A sub-entire domain (SED) basis function method, which was first introduced for modeling large-scale finite periodic PEC structures in free space, has been extended for fast characterization of electromagnetic scattering from an electrically large planar finite periodic microstrip patch array. The microstrip array may have a nonrectangular layout and non-orthogonal lattice configurations (e.g., hexagons or quadrangles). Based on the mixed potential integral equation, and utilizing the proposed SED basis function algorithm, the original large-scale finite periodic array of microstrip patches can be efficiently simulated by decomposing it into two problems with matrix equations of small dimensions. The first is to construct the SED basis functions for the corresponding microstrip arrays with orthogonal/non-orthogonal lattices. Three kinds of the SED basis functions are constructed, including those related to the edge patch elements, the interior patch elements, and the corner patch elements. The second is to solve the system equation with significantly reduced problem dimension as compared to the original larger problem. Based on the obtained SED basis functions, the reduced matrix equation of small size can be generated by the Galerkin procedure, and solved by use of the LU (lower-upper) decomposition-based direct solver, which results in a fast solution. The accuracy and efficiency of the developed algorithms are demonstrated by numerical tests that include the scattering from several large-scale finite periodic arrays of microstrip patches with rectangular, non-orthogonal lattices.
Autors: Wang, X.;Werner, D.H.;Turpin, J.P.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2014, volume: 62, issue:5, pages: 2543 - 2552
Publisher: IEEE
 
» A Fast Finite Element Model Taking Into Account 3-D Effects for the Optimal Design of Micro-Hybrid Starters
Abstract:
This paper presents a fast design method taking into account 3-D effects in a reinforced brushed dc motor used as starter in automotive application. Because of their low cost and simplicity, reinforced starters are used in micro-hybrid vehicles. The specific geometry of such devices induces an axial component of the flux which cannot be accounted for by 2-D models. 3-D finite element (FE) models are suitable for this purpose but their excessive need of CPU time complicates their use in an automatic optimization procedure. We propose to identify the overhang effects by using an adapted and corrected 2.5-D FE model which is validated by 3-D computations and experiments. Finally, the 2.5-D model is implemented in a multiobjective optimization procedure.
Autors: Andreux, R.;Fontchastagner, J.;Takorabet, N.;Labbe, N.;
Appeared in: IEEE Transactions on Magnetics
Publication date: May 2014, volume: 50, issue:5, pages: 1 - 8
Publisher: IEEE
 
» A Fast Simple Optical Flow Computation Approach Based on the 3-D Gradient
Abstract:
Optical flow estimation is a fundamental task of many computer vision applications. In this paper, we propose a fast simple algorithm to compute optical flow based on the 3-D gradient in video sequences. Although the algorithm does not provide highly accurate results, it is computationally simple and fast, and the output is applicable for many applications. The basic idea is that points will form trajectories in video sequences, and the trajectory between two frames of each point is approximated as a straight line, which is the tangent of the trajectory in our algorithm. Therefore, the optical flow of each point is the projecting line of the straight line, which represents its trajectory, in the image plane. Experimental results show that the proposed algorithm is efficient and effective, and is of satisfying accuracy on angle. It is able to provide effective optical flow results for real-time applications.
Autors: Li, Y.;Zhu, E.;Zhao, J.;Yin, J.;Zhao, X.;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: May 2014, volume: 24, issue:5, pages: 842 - 853
Publisher: IEEE
 
» A Fast-Response Hybrid SIMO Power Converter with Adaptive Current Compensation and Minimized Cross-Regulation
Abstract:
Slow load transient response and potential cross-regulation effect are two major performance barriers for single-inductor multiple-output (SIMO) power converters. To overcome these barriers, this paper presents a parallel-structured hybrid SIMO power converter with an adaptive current compensation (ACC) technique. With the employment of new and compact linear regulators, the proposed ACC technique improves both the step-up/down transient responses significantly without the needs on advanced controls or high switching frequency. The interactive duty ratio changes between sub-converters are also avoided due to the fast recovery during load transition periods. Cross-regulation effect is thus minimized. The SIMO power converter is fabricated with 0.35 µm CMOS process. The input voltage is 3 V and two output voltages are regulated at 1.8 V and 1.2 V, respectively, with a switching frequency of 500 kHz. The peak efficiency is measured at 82.8% with 102-mW load power. A 50.3-ns transient response time is achieved with 270-mW load change. No observable cross-regulation is found during load transient measurements.
Autors: Zhang, Y.;Ma, D.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: May 2014, volume: 49, issue:5, pages: 1242 - 1255
Publisher: IEEE
 
» A Fault-Tolerant PMSG Drive for Wind Turbine Applications With Minimal Increase of the Hardware Requirements
Abstract:
Fault-tolerant permanent magnet synchronous generator (PMSG) drives for wind turbine applications play a major role in improving reliability and availability levels, since power converters are very prone to fail. In this paper, a fault-tolerant converter with the ability to handle power switch open-circuit faults is addressed. The main concern of the proposed converter topology is the minimization of the hardware requirements, leading to a low increase of the system cost. First, the employed fault diagnostic technique does not require additional measurements, nor high computational effort. Secondly, the circuit topology reconfiguration implies a minimum number of extra components as well as minimal oversizing of the standard ones. Accordingly, a four-switch three-phase converter with the dc bus midpoint connected to the transformer neutral point and a three-switch three-phase rectifier are adopted for post-fault operation of the grid- and PMSG-side converters, respectively. Vector control strategies are proposed for both converters under analysis, focusing the issues of capacitor voltages balancing and torque ripple minimization. The performance of the proposed fault-tolerant PMSG drive is analyzed by means of experimental results.
Autors: Freire, N.M.A.;Cardoso, A.J.M.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: May 2014, volume: 50, issue:3, pages: 2039 - 2049
Publisher: IEEE
 
» A First Step Toward Cost Functions for Quantum-Dot Cellular Automata Designs
Abstract:
Quantum-dot cellular automata (QCA) is potentially a very attractive alternative to CMOS for future digital designs. Circuit designs in QCA have been extensively studied. However, how to properly evaluate the QCA circuits has not been carefully considered. To date, metrics and area-delay cost functions directly mapped from CMOS technology have been used to compare QCA designs, which is inappropriate due to the differences between these two technologies. In this paper, several cost metrics specifically aimed at QCA circuits are studied. It is found that delay, the number of QCA logic gates, and the number and type of crossovers, are important metrics that should be considered when comparing QCA designs. A family of new cost functions for QCA circuits is proposed. As fundamental components in QCA computing arithmetic, QCA adders are reviewed and evaluated with the proposed cost functions. By taking the new cost metrics into account, previous best adders become unattractive and it has been shown that different optimization goals lead to different “best” adders.
Autors: Liu, W.;Lu, L.;ONeill, M.;Swartzlander, E.E.;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: May 2014, volume: 13, issue:3, pages: 476 - 487
Publisher: IEEE
 
» A Flexible NISC-Based LDPC Decoder
Abstract:
Low density parity-check (LDPC) codes, are widely used for error correction in digital communication systems. Their inclusion in communication standards requires to define decoders able to support efficiently a set of codes with different code length, code rates or code structures. In addition to this high flexibility, these decoders still have to achieve high throughputs in order to comply with standards requirements. In this paper, we propose to address the problem of designing generic and efficient LDPC decoders by using a nonsymmetric NISC-based architecture that performs layered decoding. NISC architectures provide flexibility with a limited loss in hardware efficiency. In addition, an automated design flow is used to efficiently assign computations to the processing units (PU) and to map data to the memory units (MU). Unlike previous works, the NISC decoder can include a number of PUs that is different than the number of MUs. This nonsymmetric characteristic provides a higher degree of freedom during the computation/data assignment phase of the design flow. This whole design framework automatically generates an LDPC decoder able to support any set of predetermined LDPC codes regardless of their parameters. The automated nature of the design framework enables to easily explore the design space for a given set of codes. Compared to state of the art LDPC decoders, the automatically generated decoders achieve higher hardware efficiency even for the challenging-to-implement unstructured LDPC codes.
Autors: Le Gal, B.;Jego, C.;Leroux, C.;
Appeared in: IEEE Transactions on Signal Processing
Publication date: May 2014, volume: 62, issue:10, pages: 2469 - 2479
Publisher: IEEE
 
» A Floating Analog Memristor Emulator Circuit
Abstract:
This brief introduces a new floating memristor emulator circuit based on second-generation current conveyors and passive elements. A mathematical model to characterize the memristor behavior was derived, showing a good accuracy among HSPICE simulations and experimental results. An analysis of the frequency behavior of the memristor is also described, showing that the frequency-dependent pinched hysteresis loop in the current-versus-voltage plane holds up to 20.2 kHz. Theoretical derivations and related results are experimentally validated through implementations from commercially available devices, and the proposed memristor emulator circuit can easily be reproducible at a low cost. Furthermore, the emulator circuit can be used as a teaching aid and for future applications with memristors, such as sensors, cellular neural networks, chaotic systems, programmable analog circuits, and nonvolatile memory devices.
Autors: Sanchez-Lopez, C.;Mendoza-Lopez, J.;Carrasco-Aguilar, M.A.;Muniz-Montero, C.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: May 2014, volume: 61, issue:5, pages: 309 - 313
Publisher: IEEE
 
» A Fond Farewell to The Lab: The Demolition of Building 9 [History]
Abstract:
Recently, I drove out the Tyler Street Extension in Pittsfield, Massachusetts, to view the ongoing demolition of Building 9 in the former General Electric Company (GE) plant. Building 9 once had been a world-renowned center of high-voltage and lightning research. It was named the GE High Voltage Laboratory and was commonly referred to as ?The Lab.?
Autors: Blalock, T.;
Appeared in: IEEE Power and Energy Magazine
Publication date: May 2014, volume: 12, issue:3, pages: 110 - 112
Publisher: IEEE
 
» A Four-Channel 32-Gb/s Transceiver With Current-Recycling Output Driver and On-Chip AC Coupling in 65-nm CMOS Process
Abstract:
This brief describes the design of a four-channel 32-Gb/s serial link transmitter with a current-recycling output driver and an on-chip ac-coupled receiver. The proposed output driver significantly reduces power dissipation in the final stage of the transmitter by reusing the natural current flow through the four-channel outputs. It also eliminates the voltage regulation circuit and the current source circuitry for generating low-swing outputs. Since the four-channel outputs are stacked from the ground to the supply rail with different common-mode output levels, the receiver should include an ac-coupling circuit to establish the desired common-mode voltage level for the receive amplifier in each channel. A long-time constant is realized in the ac-coupling circuit with small on-chip capacitors. The prototype chip has been fabricated in the 65-nm low-power CMOS process, and the transmitter supports an output swing of 300 at a data rate of 8 Gb/s. The four stacked output drivers only consume a total static power of 1.8 mW, and the overall transceiver, including an equalization of 7 dB, exhibits a normalized power dissipation of 2.04 mW/Gb/s.
Autors: Kim, T.;Jang, S.;Kim, S.;Chu, S.;Park, J.;Jeong, D.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: May 2014, volume: 61, issue:5, pages: 304 - 308
Publisher: IEEE
 
» A FVF LDO Regulator With Dual-Summed Miller Frequency Compensation for Wide Load Capacitance Range Applications
Abstract:
This paper presents a proposed Flipped Voltage Follower (FVF) based output capacitorless low-dropout (OCL-LDO) regulator using Dual-Summed Miller Frequency Compensation (DSMFC) technique. Validated by UMC 65-nm CMOS process, the simulation results have shown that the proposed LDO regulator can be stabilized by a total compensation capacitance of 8 pF for a load capacitance ranging from 10 pF to 10 nF. It consumes 23.7 A quiescent current with a 1.2 V supply voltage. With a dropout voltage of 200 mV, the LDO regulator can support a maximum 50 mA load current. It can settle in less than 1.7 s with a 1% accuracy for the whole range. The proposed LDO regulator is comparable to other reported works in terms of figure-of-merit (FOM). Most significantly, it can drive the widest range of and achieve the highest ratio with respect to the counterparts.
Autors: Tan, X.L.;Koay, K.C.;Chong, S.S.;Chan, P.K.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: May 2014, volume: 61, issue:5, pages: 1304 - 1312
Publisher: IEEE
 
» A General, Tractable and Accurate Model for a Cascade of LRU Caches
Abstract:
The recent evolution of the Internet towards "Information-centric" transfer modes has renewed the interest in characterizing multi-cache systems, in which requests not satisfied by a cache are forwarded to other caches. In this work, we characterize the traffic statistics of the output (miss) stream, via a simple but accurate approximate analysis for LRU caches feeded by general "renewal" traffic patterns. In turn, we exploit such output stream traffic pattern to analyze the performance of the subsequent cache stage, and so on. The computational efficiency of our model, joint with its ability to handle traffic patterns beyond the traditional independent reference model, permits simple and tractable assessment of cache hierarchies.
Autors: Melazzi, N.Blefari;Bianchi, G.;Caponi, A.;Detti, A.;
Appeared in: IEEE Communications Letters
Publication date: May 2014, volume: 18, issue:5, pages: 877 - 880
Publisher: IEEE
 
» A generalized lumped-element equivalent circuit for tunable magnetoelectric microwave devices with multi-magnetoelectric laminates
Abstract:
According to the microwave transmission principle and the mechanism of ferromagnetic resonance, a generalized lumped element model for electrically and magnetically magnetoelectric tunable microwave devices with multi-magnetoelectric laminates is established. This model is introduced the RLC series resonant circuit and an ideal transformer model to characterize the ferromagnetic resonance effect and the coupling between microstrip line and the magnetoelectric laminates. Then, the model is degenerated to an existing microwave resonator, which contains only a single block magnetoelectric laminate, and transmission characteristics results predicted by the lumped element model are compared with the experimental results and the electromagnetic simulated results. It is found that the lumped circuit model can effectively predict the center frequency and bandwidth of the resonator. After that, the lumped element model is used to predict the band characteristics and the magnetic and electric tunability of the filter with multi-magnetoelectric laminates. The results show that the application of multi-magnetoelectric laminates in filters can not only broaden bandwidth, but also control the work frequency band by tuning the external electrostatic and magnetostatic field on the magnetoelectric laminates. Therefore, considering the practicality and versatility of microwave devices with multi-magnetoelectric laminates, the effective lumped element model can provide the theoretical basis for the design of novel magnetoelectric devices.
Autors: Zhou, Hao-Miao;Lian, Jing;
Appeared in: Journal of Applied Physics
Publication date: May 2014, volume: 115, issue:19, pages: 193908 - 193908-8
Publisher: IEEE
 
» A Generic Approach for Solving Nonlinear-Discrete Security-Constrained Optimal Power Flow Problems in Large-Scale Systems
Abstract:
This paper proves the practicality of an iterative algorithm for solving realistic large-scale security-constrained optimal power flow (SCOPF) problems. This algorithm is based on the combination of a contingency filtering scheme, used to identify the binding contingencies at the optimum, and a network compression method, used to reduce the complexity of the post-contingency models included in the SCOPF formulation. We show that by combining these two complementary ideas, it is possible to solve in a reasonable time SCOPF problems on large power system models with a large number of contingencies. Unlike most results reported for large-scale SCOPF problems, our algorithm uses a nonlinear AC network model in both pre-contingency and post-contingency states, optimizes both active/reactive powers flows jointly, and treats the discrete variables. The proposed algorithm is implemented with state-of-the-art solvers and applied to two systems: a national grid with 2563 buses and 1297 contingencies, and a model of the European transmission network with 9241 buses and 12 000 contingencies.
Autors: Platbrood, L.;Capitanescu, F.;Merckx, C.;Crisciu, H.;Wehenkel, L.;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2014, volume: 29, issue:3, pages: 1194 - 1203
Publisher: IEEE
 
» A Genetic Algorithm-Based Low Voltage Ride-Through Control Strategy for Grid Connected Doubly Fed Induction Wind Generators
Abstract:
This paper proposes a new computational intel ligence-based control strategy, to enhance the low voltage ride-through capability of grid-connected wind turbines (WTs) with doubly fed induction generators (DFIGs). Grid codes world-wide require that WTs should supply reactive power to the grid during and after the fault, in order to support the grid voltage. The conventional crowbar-based systems that were initially applied in order to protect the rotor-side converter at the occurrence of grid faults, do not fulfill this requirement, as during the connection of the crowbar, the DFIG behaves as a squirrel cage machine, absorbing reactive power from the grid. This drawback led to the design of control systems that eliminate or even avoid the use of the crowbar. In order to conform to the above-mentioned requirement, this paper proposes a coordinated control strategy of the DFIG converters during a grid fault, managing to ride-through the fault without the use of any auxiliary hardware. The coordination of the two controllers is achieved via a fuzzy controller which is properly tuned using genetic algorithms. To validate the proposed control strategy, a case study of a 1.5-MW DFIG supplying a relatively weak electrical system is carried out by simulation.
Autors: Vrionis, T.D.;Koutiva, X.I.;Vovos, N.A.;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2014, volume: 29, issue:3, pages: 1325 - 1334
Publisher: IEEE
 
» A Geometric Perspective to Multiple-Unicast Network Coding
Abstract:
The multiple-unicast network coding conjecture states that for multiple unicast sessions in an undirected network, network coding is equivalent to routing. Simple and intuitive as it appears, the conjecture has remained open since its proposal in 2004, and is now a well-known unsolved problem in the field of network coding. Based on a recently proposed tool of space information flow, we present a geometric framework for analyzing the multiple-unicast conjecture. The framework consists of four major steps, in which the conjecture is transformed from its throughput version to cost version, from the graph domain to the space domain, and then from high dimension to 1-D, where it is to be eventually proved. We apply the geometric framework to derive unified proofs to known results of the conjecture, as well as new results previously unknown. A possible proof to the conjecture based on this framework is outlined.
Autors: Xiahou, T.;Li, Z.;Wu, C.;Huang, J.;
Appeared in: IEEE Transactions on Information Theory
Publication date: May 2014, volume: 60, issue:5, pages: 2884 - 2895
Publisher: IEEE
 
» A Glue Splicing Method to Join Silica and Fluoride Fibers With Low Attenuation
Abstract:
We improved our glue splicing method to join silica and fluoride glass fibers. It is now even more robust and stabile with a mean loss below 0.5 dB. Moreover, the splice reflection was reduced to about -42 dB when an index matching gel was used. Pieces of Pr3+/Yb3+ doped ZBLAN fibers with lengths of 25 cm were connected to silica fibers. In a fiber laser resonator 6 mW of red laser radiation was achieved with the spliced fibers at a pump power level of 144 mW at 845 nm.
Autors: Al-Mahrous, R.;Caspary, R.;Kowalsky, W.;
Appeared in: Journal of Lightwave Technology
Publication date: May 2014, volume: 32, issue:9, pages: 1669 - 1673
Publisher: IEEE
 
» A GPU-Accelerated Web-Based Synthesis Tool for CT Sigma-Delta Modulators
Abstract:
This paper presents a design environment for continuous-time sigma-delta analog-to-digital converters for automatic coefficient scaling using a genetic algorithm. In order to provide an interactive design tool which enables the designer to transform and refine basic performance specifications into the desired, detailed high-level filter description, a short response time is mandatory. Previously published heuristic-search-based design tools have response times in the range of several ten minutes up to hours and are mostly not freely available. In contrast, the design environment presented in this paper provides results in less than a minute due the utilization of a fast simulation method implemented on a graphics card processor. Our hardware supported approach allows performing between 10 k and 67 k simulations and evaluations per second for internal model orders of one to eight, allowing to investigate millions of settings in less than a minute. The presented tool is freely accessible under www.sigma-delta.de.
Autors: Bruckner, T.;Zorn, C.;Anders, J.;Becker, J.;Mathis, W.;Ortmanns, M.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: May 2014, volume: 61, issue:5, pages: 1429 - 1441
Publisher: IEEE
 
» A Graph Derivation Based Approach for Measuring and Comparing Structural Semantics of Ontologies
Abstract:
Ontology reuse offers great benefits by measuring and comparing ontologies. However, the state of art approaches for measuring ontologies neglects the problems of both the polymorphism of ontology representation and the addition of implicit semantic knowledge. One way to tackle these problems is to devise a mechanism for ontology measurement that is stable, the basic criteria for automatic measurement. In this paper, we present a graph derivation representation based approach (GDR) for stable semantic measurement, which captures structural semantics of ontologies and addresses those problems that cause unstable measurement of ontologies. This paper makes three original contributions. First, we introduce and define the concept of semantic measurement and the concept of stable measurement. We present the GDR based approach, a three-phase process to transform an ontology to its GDR. Second, we formally analyze important properties of GDRs based on which stable semantic measurement and comparison can be achieved successfully. Third but not the least, we compare our GDR based approach with existing graph based methods using a dozen real world exemplar ontologies. Our experimental comparison is conducted based on nine ontology measurement entities and distance metric, which stably compares the similarity of two ontologies in terms of their GDRs.
Autors: Ma, Y.;Liu, L.;Lu, K.;Jin, B.;Liu, X.;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: May 2014, volume: 26, issue:5, pages: 1039 - 1052
Publisher: IEEE
 
» A Grid-Friendly Plant: The Role of Utility-Scale Photovoltaic Plants in Grid Stability and Reliability
Abstract:
A Recent rapid Photovoltaic (PV) price reduction has significantly increased the competitiveness of PV-generated electricity, which has now reached grid parity in many markets, i.e., electricity is produced at the same or a lower price than conventional electricity sources. Along with other factors stimulating the global growth of renewable energy, this cost decline has greatly increased both the number and size of utility-scale solar plants, especially PVs, that are deployed on the power grid. The impact on power systems of integrating PV generation, especially as it relates to grid reliability and stability, needs to be addressed.
Autors: Morjaria, M.;Anichkov, D.;Chadliev, V.;Soni, S.;
Appeared in: IEEE Power and Energy Magazine
Publication date: May 2014, volume: 12, issue:3, pages: 87 - 95
Publisher: IEEE
 
» A Harmonic Termination Technique for Single- and Multi-Band High-Efficiency Class-F MMIC Power Amplifiers
Abstract:
Pub DtlThis paper presents a harmonic termination technique for single- and multi-band high-efficiency class-F monolithic microwave integrated circuit (MMIC) power amplifiers (PAs). The harmonic termination network (HTN), realized with the minimum possible number of elements, can be used to terminate an arbitrary number of harmonics in a single-band PA or harmonics of multiple frequencies in a concurrent multi-band PA. The drain and gate bias lines are embedded in the HTNs to obviate the need for RF chokes and reduce the chip area. A single- and a dual-band MMIC PA are designed using the proposed technique and implemented in a 0.25- AlGaAs–InGaAs pHEMT technology. The single-band 5.5-GHz PA provides 27.5 dBm of output power with 70% power-added efficiency (PAE). This PAE level is achieved by terminating the first five harmonics at the output as well as the first three harmonics at the input of PA. The dual-band PA, operating at 5 and 12 GHz, delivers the output power of 28.0 and 26.7 dBm with PAE of 58% and 51%, at the two frequency bands, respectively.
Autors: Nikandish, G.;Babakrpur, E.;Medi, A.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: May 2014, volume: 62, issue:5, pages: 1212 - 1220
Publisher: IEEE
 
» A high precision, compact electromechanical ground rotation sensor
Abstract:
We present a mechanical rotation sensor consisting of a balance pivoting on a tungsten carbide knife edge. These sensors are important for precision seismic isolation systems, as employed in land-based gravitational wave interferometers and for the new field of rotational seismology. The position sensor used is an air-core linear variable differential transformer with a demonstrated noise floor of 1×10−11m/ Hz . We describe the instrument construction and demonstrate low noise operation with a noise floor upper bound of 5.7×10−9 rad / Hz at 10 mHz and 6.4×10−10 rad / Hz at 0.1 Hz. The performance of the knife edge hinge is compatible with a behaviorur free of noise from dislocation self-organized criticality.
Autors: Dergachev, V.;DeSalvo, R.;Asadoor, M.;Bhawal, A.;Gong, P.;Kim, C.;Lottarini, A.;Minenkov, Y.;Murphy, C.;O'Toole, A.;Pena Arellano, F.E.;Rodionov, A.V.;Shaner, M.;Sobacchi, E.;
Appeared in: Review of Scientific Instruments
Publication date: May 2014, volume: 85, issue:5, pages: 054502 - 054502-13
Publisher: IEEE
 
» A Highly-Efficient Multi-Band Multi-Mode All-Digital Quadrature Transmitter
Abstract:
A novel highly-efficient multi-band multi-mode all-digital quadrature transmitter is presented. In the transmitter, a switching-mode power amplifier (PA), also referred to as digital power amplifier (DPA), which consists of an in-phase PA (I-PA) and a quadrature PA (Q-PA), is controlled by the digital codewords based on an input signal to turn on and off the power cells inside the I-PA or the Q-PA. Due to the load interaction between the I-PA and the Q-PA, a 2-dimensional (2-D) digital pre-distortion (DPD) is applied to linearize the DPA. The whole transmitter is implemented in 40 nm CMOS LP process and occupies a die area of 0.7 . The all-digital quadrature transmitter can support 20 MHz, 40 MHz, and 80 MHz WiFi signals, Band 38 and Band 40 LTE signals with class 3 output power, and Bluetooth BDR, EDR2, and EDR3 signals.
Autors: Wang, H.;Peng, C.-H.;Chang, Y.;Huang, R.Z.;Chang, C.-W.;Shih, X.-Y.;Hsu, C.-J.;Liang, P.C.P.;Niknejad, A.M.;Chien, G.;Tsai, C.L.;Hwang, H.C.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: May 2014, volume: 61, issue:5, pages: 1321 - 1330
Publisher: IEEE
 
» A Holographic In-Line Imaging System for Meteorological Applications
Abstract:
A digital holographic in-line imaging instrument aimed for meteorological measurements is presented. The system is designed to capture detailed information of macroscopic hydrometeors in a large imaging volume. We suggest the use of holographic imaging to overcome the depth of field limitations of conventional macroimaging systems in meteorological imaging applications. The first low magnification holographic imaging prototype built for measuring free falling hydrometeors in the size range of a few tens of micrometers to several millimeters is described. The design of the imaging setup is discussed in detail, calibration and characterization measurements of magnification, position accuracy, and resolving power are presented. Field measurements during snow falls and rain were made and reconstructed images of snowflakes and raindrops are shown and analyzed. The results of laboratory tests and the field tests show high quality and resolution of reconstructed holograms to enable detailed image analyses on snowflakes, raindrops, and other types of hydrometeors.
Autors: Kaikkonen, V.A.;Ekimov, D.;Makynen, A.J.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: May 2014, volume: 63, issue:5, pages: 1137 - 1144
Publisher: IEEE
 
» A Hybrid Mode Matching-Finite Element Method and Spectral Decomposition Approach for the Analysis of Large Finite Phased Arrays of Waveguides
Abstract:
In this paper, a new hybrid mode matching-finite element-spectral decomposition (MM-FE-SD) approach applied to the analysis of finite large arrays is presented. The proposed technique combines the numerical efficiency of the MM procedure, applied to the unit cell, with the capability of the SD to reduce the finite problem to a superposition of several doubly-periodic ones. In particular, the MM-FE is applied to the analysis of an infinite phased array of apertures arranged in a triangular lattice and fed by rectangular waveguides with thick irises. The irises as well as the waveguides may be arbitrarily shaped, and the effect of dielectric sheet radomes can also be accounted for. Representative numerical examples are shown to demonstrate the effectiveness of the method.
Autors: Pellegrini, A.;Monorchio, A.;Manara, G.;Mittra, R.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2014, volume: 62, issue:5, pages: 2553 - 2561
Publisher: IEEE
 
» A Hybrid Pricing Framework for TV White Space Database
Abstract:
According to the recent rulings of the Federal Communications Commission (FCC), TV white spaces (TVWS) can now be accessed by secondary users (SUs) after a list of vacant TV channels is obtained via a geo-location database. Proper business models are therefore essential for database operators to manage geo-location databases. Database access can be simultaneously priced under two different schemes: the registration scheme and the service plan scheme. In the registration scheme, the database reserves part of the TV bandwidth for registered White Space Devices (WSDs). In the service plan scheme, the WSDs are charged according to their queries. In this paper, we investigate the business model for the TVWS database under a hybrid pricing scheme. We consider the scenario where a database operator employs both the registration scheme and the service plan scheme to serve the SUs. The SUs' choices of different pricing schemes are modeled as a non-cooperative game and we derive distributed algorithms to achieve Nash Equilibrium (NE). Considering the NE of the SUs, the database operator optimally determines pricing parameters for both pricing schemes in terms of bandwidth reservation, registration fee and query plans.
Autors: Feng, Xiaojun;Zhang, Qian;Zhang, Jin;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: May 2014, volume: 13, issue:5, pages: 2626 - 2635
Publisher: IEEE
 
» A Hybrid Time-Domain Discontinuous Galerkin-Boundary Integral Method for Electromagnetic Scattering Analysis
Abstract:
A scheme hybridizing discontinuous Galerkin time-domain (DGTD) and time-domain boundary integral (TDBI) methods for accurately analyzing transient electromagnetic scattering is proposed. Radiation condition is enforced using the numerical flux on the truncation boundary. The fields required by the flux are computed using the TDBI from equivalent currents introduced on a Huygens' surface enclosing the scatterer. The hybrid DGTDBI ensures that the radiation condition is mathematically exact and the resulting computation domain is as small as possible since the truncation boundary conforms to scatterer's shape and is located very close to its surface. Locally truncated domains can also be defined around each disconnected scatterer additionally reducing the size of the overall computation domain. Numerical examples demonstrating the accuracy and versatility of the proposed method are presented.
Autors: Li, P.;Shi, Y.;Jiang, L.J.;Bagci, H.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2014, volume: 62, issue:5, pages: 2841 - 2846
Publisher: IEEE
 
» A Hybrid-Switch-Based Soft-Switching Inverter for Ultrahigh-Efficiency Traction Motor Drives
Abstract:
This paper presents a hybrid switch that parallels a power MOSFET and an insulated-gate bipolar transistor (IGBT) as the main switch of a zero-voltage switching (ZVS) inverter. The combination features the MOSFET conducting in the low-current region and the IGBT conducting in the high-current region, and the soft switching avoids the reverse recovery problem during the device turn-on. A custom hybrid switch module has been developed for a variable-timing-controlled coupled-magnetic-type ZVS inverter with a nominal input voltage of 325 V and the continuous output power of 30 kW for a traction motor drive. Experimental results of the hybrid-switch-based inverter with the total loss projected by temperature indicate that the inverter achieves 99% efficiency at the nominal condition and demonstrate ultrahigh-efficiency operation over a wide load range. At 375-V input, the maximum measured efficiency through temperature projection and loss separation analysis is 99.3%.
Autors: Lai, J.;Yu, W.;Sun, P.;Leslie, S.;Arnet, B.;Smith, C.;Cogan, A.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: May 2014, volume: 50, issue:3, pages: 1966 - 1973
Publisher: IEEE
 
» A hydrodynamic microchip for formation of continuous cell chains
Abstract:
Here, we demonstrate the unique features of a hydrodynamic based microchip for creating continuous chains of model yeast cells. The system consists of a disk shaped microfluidic structure, containing narrow orifices that connect the main channel to an array of spoke channels. Negative pressure provided by a syringe pump draws fluid from the main channel through the narrow orifices. After cleaning process, a thin layer of water is left between the glass substrate and the polydimethylsiloxane microchip, enabling leakage beneath the channel walls. A mechanical clamp is used to adjust the operation of the microchip. Relaxing the clamp allows leakage of liquid beneath the walls in a controllable fashion, leading to formation of a long cell chain evenly distributed along the channel wall. The unique features of the microchip are demonstrated by creating long chains of yeast cells and model 15 μm polystyrene particles along the side wall and analysing the hydrogen peroxide induced death of patterned cells.
Autors: Khoshmanesh, Khashayar;Zhang, Wei;Tang, Shi-Yang;Nasabi, Mahyar;Soffe, Rebecca;Tovar-Lopez, Francisco J.;Rajadas, Jayakumar;Mitchell, Arnan;
Appeared in: Applied Physics Letters
Publication date: May 2014, volume: 104, issue:20, pages: 203701 - 203701-5
Publisher: IEEE
 
» A Joint Design for Distributed Stable Routing and Channel Assignment Over Multihop and Multiflow Mobile Ad Hoc Cognitive Networks
Abstract:
Data communication in mobile ad hoc cognitive networks (MACNets) significantly suffers from link instability and channel interference. The availability and stability of each link in MACNets highly depends on not only the relative movement of neighbor nodes but also the adjacent communication among primary nodes and among cognitive nodes. In multihop and multiflow MACNets, this problem becomes even worse because multiple links potentially interfere with each other. In this paper, we propose a cross-layer distributed approach, called mobility-prediction-based joint stable routing and channel assignment (MP-JSRCA), to maximize the network throughput by jointly selecting stable routes and assigning channels avoiding inter- and intra-flow interferences based on mobility prediction. To quantitatively measure the communication quality of links, we propose a new metric data transmission cost (DTC) that captures node mobility, impact to primary nodes, and channel conflict among cognitive nodes. In our MP-JSRCA, each relay node selects the best link with the smallest DTC as the next hop, within a specified sector region towards the destination. NS2-based simulation results demonstrate that our MP-JSRCA algorithm significantly improves network throughput, and the higher degree of interference MACNets experience, the more improvement can be achieved.
Autors: Tang, F.;Barolli, L.;Li, J.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: May 2014, volume: 10, issue:2, pages: 1606 - 1615
Publisher: IEEE
 
» A Joint Duty-Cycle and Transmission Power Management for Energy Harvesting WSN
Abstract:
In this paper, we propose a global power management approach for energy harvesting sensor nodes. Our approach is based on a joint duty-cycle optimization and transmission power control. By simultaneously adapting both parameters, the node can maximize the number of transmitted packets while respecting the limited and time-varying amount of available energy. We obtain a high-packet delivery by using an original predictive transmission power control that can efficiently adapt the transmission power to the wireless channel conditions. To accurately model the wireless channel and the node communication hardware, a waveform-level radio frequency simulator has been developed. Simulation results show 6.5 times improvement in energy efficiency and a packet reception ratio which is 9 times more efficient than a recently published technique. A 15% increase in energy efficiency, with respect to a fixed transmission power configuration, has also been observed. Finally, the global power management strategy has been validated on a real wireless sensor networks platform. Experimental results are very similar to those obtained in simulations, and thus confirm the efficiency of our power management approach.
Autors: Castagnetti, A.;Pegatoquet, A.;Le, T.N.;Auguin, M.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: May 2014, volume: 10, issue:2, pages: 928 - 936
Publisher: IEEE
 
» A ladder of polariton branches formed by coupling an organic semiconductor exciton to a series of closely spaced cavity-photon modes
Abstract:
We construct a microcavity in which the extended optical path length of the cavity (5.9 μm) permits a series of closely spaced optical modes to be supported. By placing a J-aggregated cyanine dye into the cavity, we reach the strong-coupling regime and evidence a simultaneous optical hybridization between the organic-exciton and a number of the confined cavity modes, forming an effective ladder of polariton branches. We explore the emission from such cavities and evidence a polariton-population on adjacent polariton branches around k = 0.
Autors: Coles, David M.;Lidzey, David G.;
Appeared in: Applied Physics Letters
Publication date: May 2014, volume: 104, issue:19, pages: 191108 - 191108-4
Publisher: IEEE
 
» A Linearizing Digitizer for Differential Sensors With Polynomial Characteristics
Abstract:
This paper presents a new linearizing digital converter (LDC) that accepts output from differential type sensors with third-order polynomial transfer characteristics and provides a linear digital output proportional to the measurand. The LDC is realized using a modified dual-slope converter. Detailed operation of the proposed LDC, design procedure, and analysis of the effect of various circuit parameters on performance of the LDC are presented in this paper. The proposed methodology of LDC is also extended for sensors with second-order polynomial characteristics. The functionality of the LDC has been verified with the help of simulation studies. A prototype LDC has been developed and interfaced with a novel reluctance-Hall effect-based angle sensor (having a third-order characteristic) and tested. Test results show that the output of the overall transducer is linear across a wide range of angles, and thus underline the efficacy of the proposed scheme for differential type sensors with third-order transfer characteristics.
Autors: Sreekantan, A.C.;George, B.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: May 2014, volume: 63, issue:5, pages: 1022 - 1031
Publisher: IEEE
 
» A long-pulse repetitive operation magnetically insulated transmission line oscillator
Abstract:
The improved magnetically insulated transmission line oscillator (MILO) is a gigawatt-class L-band high power microwave tube. It has allowed us to generate 3.1 GW pulse of 40 ns duration in the single-pulse operation and 500 MW pulse of 25 ns duration in the repetition rate operation. However, because of the severe impedance mismatch, the power conversion efficiency is only about 4% in the repetition rate operation. In order to eliminate the impedance mismatch and obtain repetitive long-pulse high-power microwave (HPM), a series of experiments are carried out and the recent progress is presented in this paper. In the single-pulse operation, when the diode voltage is 466 kV and current is 41.6 kA, the radiated microwave power is above 2.2 GW, the pulse duration is above 102 ns, the microwave frequency is about 1.74 GHz, and the power conversion efficiency is about 11.5%. In the repetition rate operation, under the condition of the diode voltage about 400 kV, beam current about 38 kA, the radiated microwave power is about 1.0 GW, the pulse duration is about 85 ns. Moreover, the radiated microwave power and the pulse duration decline little by little when the shot numbers increase gradually. The experimental results show that the impedance matching is a vital factor for HPM systems and one of the major technical challenges is to improve the cathode for the repetition rate operation MILO.
Autors: Fan, Yu-Wei;Zhong, Hui-Huang;Zhang, Jian-De;Shu, Ting;Liu, Jin Liang;
Appeared in: Review of Scientific Instruments
Publication date: May 2014, volume: 85, issue:5, pages: 053512 - 053512-4
Publisher: IEEE
 
» A Look-Ahead Clock Gating Based on Auto-Gated Flip-Flops
Abstract:
Clock gating is very useful for reducing the power consumed by digital systems. Three gating methods are known. The most popular is synthesis-based, deriving clock enabling signals based on the logic of the underlying system. It unfortunately leaves the majority of the clock pulses driving the flip-flops (FFs) redundant. A data-driven method stops most of those and yields higher power savings, but its implementation is complex and application dependent. A third method called auto-gated FFs (AGFF) is simple but yields relatively small power savings. This paper presents a novel method called Look-Ahead Clock Gating (LACG), which combines all the three. LACG computes the clock enabling signals of each FF one cycle ahead of time, based on the present cycle data of those FFs on which it depends. It avoids the tight timing constraints of AGFF and data-driven by allotting a full clock cycle for the computation of the enabling signals and their propagation. A closed-form model characterizing the power saving per FF is presented. It is based on data-to-clock toggling probabilities, capacitance parameters and FFs' fan-in. The model implies a breakeven curve, dividing the FFs space into two regions of positive and negative gating return on investment. While the majority of the FFs fall in the positive region and hence should be gated, those falling in the negative region should not. Experimentation on industry-scale data showed 22.6% reduction of the clock power, translated to 12.5% power reduction of the entire system.
Autors: Wimer, S.;Albahari, A.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: May 2014, volume: 61, issue:5, pages: 1465 - 1472
Publisher: IEEE
 
» A Low Complexity Antenna Switching for Joint Wireless Information and Energy Transfer in MIMO Relay Channels
Abstract:
In this paper, we investigate a low-complexity technique for simultaneous wireless information and energy transfer in multiple-input multiple-output relay channels. The proposed technique exploits the array configuration at the relay node and uses the antenna elements either for conventional decoding or for rectifying (rectennas). In order to keep the complexity low, a dynamic antenna switching between decoding/rectifying is proposed based on the principles of the generalized selection combiner (GSC); the L strongest paths are allocated for decoding while the remaining channel paths for rectifying (and vice versa). The optimal L as well as the allocation strategy that minimizes the outage probability are investigated via theoretical and numerical results. In addition, two performance bounds that provide the optimal performance without the limitation of GSC are proposed by solving a linear programming and a binary knapsack problem, respectively. The proposed technique is extended to scenarios with multi-user interference, where a zero-forcing receiver is used at the relay node; closed-forms expressions for the outage probability are also derived.
Autors: Krikidis, Ioannis;Sasaki, Shigenobu;Timotheou, Stelios;Ding, Zhiguo;
Appeared in: IEEE Transactions on Communications
Publication date: May 2014, volume: 62, issue:5, pages: 1577 - 1587
Publisher: IEEE
 
» A Low Complexity-High Throughput QC-LDPC Encoder
Abstract:
This paper introduces hardware architectures for encoding Quasi-Cyclic Low-Density Parity Check (QC-LDPC) codes. The proposed encoders are based on appropriate factorization and subsequent compression of involved matrices by means of a novel technique, which exploits features of recursively-constructed QC-LDPC codes. The particular approach derives to linear encoding time complexity and requires a constant number of clock cycles for the computation of parity bits for all the constructed codes of various lengths that stem from a common base matrix. The proposed architectures are flexible, as they are parameterized and can support multiple code rates and codes of different lengths simply by appropriate initialization of memories and determination of data bus widths. Implementation results show that the proposed encoding technique is more efficient for some LDPC codes than previously proposed solutions. Both serial and parallel architectures are proposed. Hardware instantiations of the proposed serial encoders demonstrate high throughput with low area complexity for code words of many thousand bits, achieving area reduction compared to prior art. Furthermore, parallelization is shown to efficiently support multi-Gbps solutions at the cost of moderate area increase. The proposed encoders are shown to outperform the current state-of-the-art in terms of throughput-area-ratio and area-time complexity by 10 to up to 80 times for codes of comparable error-correction strength.
Autors: Mahdi, A.;Paliouras, V.;
Appeared in: IEEE Transactions on Signal Processing
Publication date: May 2014, volume: 62, issue:10, pages: 2696 - 2708
Publisher: IEEE
 
» A Low-Noise Fundamental-Mode Orthogonal Fluxgate Magnetometer
Abstract:
We introduce a low-noise fundamental-mode orthogonal fluxgate magnetometer for use in magnetotelluric surveys. The fluxgate makes use of rapidly quenched amorphous wire having vanishing value of saturation magnetostriction constant and displaying ultrasoft magnetic behavior. The design of the fluxgate consists of multiple U-shaped sensor heads where pairs of wire pieces are inserted as core material. The novelty of this system resides in the use of a quadruple sensor head. Digital signal processing with effective electronic noise suppression allows this magnetometer to achieve a noise floor of 0.8 for frequencies above 10 Hz. The possibilities of in situ application are discussed and guidelines on noise suppression strategies are given.
Autors: Bazinet, R.;Jacas, A.;Confalonieri, G.A.B.;Vazquez, M.;
Appeared in: IEEE Transactions on Magnetics
Publication date: May 2014, volume: 50, issue:5, pages: 1 - 3
Publisher: IEEE
 
» A matter of ethics [From the Editor's Desk]
Abstract:
The IEEE Code of Ethics guides our behavior as professionals, on issues important to the mission of the IEEE. Professional ethics are not the same as the personal or moral ethics that frame our personal beliefs on matters such as lying, stealing, or cheating. Professional and personal ethics can have two dimensions: 1) preventing and avoiding bad things and 2) enabling or promoting good things. I urge our readers to take a few minutes to read the IEEE Code of Ethics and think about how to make them part of your IAS activities.
Autors: Floyd, L.;
Appeared in: IEEE Industry Applications Magazine
Publication date: May 2014, volume: 20, issue:3, pages: 2 - 12
Publisher: IEEE
 
» A Memetic Algorithm for Resource Allocation Problem Based on Node-Weighted Graphs [Application Notes]
Abstract:
Resource allocation problems usually seek to find an optimal allocation of a limited amount of resources to a number of activities. The allocation solutions of different problems usually optimize different objectives under constraints [1, 2]. If the activities and constraints among them are presented as nodes and edges respectively, the resource allocation problem can be modeled as a k-coloring problem with additional optimization objectives [3, 4]. Since the amount of resources is limited, it is common that some of the activities (nodes) cannot obtain a resource (color). Because the importance of the nodes is usually different, let the weight of a node denote the cost if it cannot obtain a resource, then the resource allocation problem can be described by a node-weighted graph G(E,V), where E and V are the edge and node set, respectively. Some of the nodes that cannot obtain a resource will incur cost to the allocation solution. The optimization objective of the resource allocation problem formulated in this paper is to minimize the total cost of all the nodes that do not obtain a resource. If the total cost is zero, the obtained solution is a k-coloring of the graph; otherwise, the obtained solution is a k -coloring of the graph after removing the nodes that do not obtain a resource. So the resource allocation problem is a generalization of the k-coloring problem.
Autors: Wu, J.;Chang, Z.;Yuan, L.;Hou, Y.;Gong, M.;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: May 2014, volume: 9, issue:2, pages: 58 - 69
Publisher: IEEE
 

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