Log in
Register
Pages: 0123456789101112131415161718192021222324252627


Electrical and Electronics Engineering publications abstract of: 06-2014 sorted by title, page: 0
» "I" Also Stands for Innovation and Industry [Message from the President]
Abstract:
Autors: Hung, J.;
Appeared in: IEEE Industrial Electronics Magazine
Publication date: Jun 2014, volume: 8, issue:2, pages: 3 - 5
Publisher: IEEE
 
» “Clustering by Composition”—Unsupervised Discovery of Image Categories
Abstract:
We define a “good image cluster” as one in which images can be easily composed (like a puzzle) using pieces from each other, while are difficult to compose from images outside the cluster. The larger and more statistically significant the pieces are, the stronger the affinity between the images. This gives rise to unsupervised discovery of very challenging image categories. We further show how multiple images can be composed from each other simultaneously and efficiently using a collaborative randomized search algorithm. This collaborative process exploits the “wisdom of crowds of images”, to obtain a sparse yet meaningful set of image affinities, and in time which is almost linear in the size of the image collection. “Clustering-by-Composition” yields state-of-the-art results on current benchmark data sets. It further yields promising results on new challenging data sets, such as data sets with very few images (where a ‘cluster model’ cannot be ‘learned’ by current methods), and a subset of the PASCAL VOC data set (with huge variability in scale and appearance).
Autors: Faktor, A.;Irani, M.;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Jun 2014, volume: 36, issue:6, pages: 1092 - 1106
Publisher: IEEE
 
» “Follow the Sun, Follow the Wind” Lightpath Virtual Topology Reconfiguration in IP Over WDM Network
Abstract:
Green House Gas (GHG) emissions mainly come from the consumption of non-renewable energy. To reduce GHG emissions of IP over WDM networks, we propose to maximize renewable energy usage at each network node location so as to reduce the consumption of non-renewable energy. A “Follow the Sun, Follow the Wind” strategy is proposed for the IP over WDM network to periodically reconfigure the lightpath virtual topology to enable more lightpaths to start or end at nodes where maximum renewable energy is available. We develop a mixed integer linear programming model to design new lightpath virtual topologies. Since the computational complexity of the optimization model is excessive, we also propose a simple but efficient heuristic algorithm to tackle this. Our results indicate that a network operated in this way can significantly reduce non-renewable energy consumption as illustrated in the example network scenarios considered.
Autors: Shen, G.;Lui, Y.;Bose, S.K.;
Appeared in: Journal of Lightwave Technology
Publication date: Jun 2014, volume: 32, issue:11, pages: 2094 - 2105
Publisher: IEEE
 
» 'Magic in the Air' [Editorial]
Abstract:
Autors: Moer, W.V.;
Appeared in: IEEE Instrumentation & Measurement Magazine
Publication date: Jun 2014, volume: 17, issue:3, pages: 4 - 10
Publisher: IEEE
 
» 0.56 V, –20 dBm RF-Powered, Multi-Node Wireless Body Area Network System-on-a-Chip With Harvesting-Efficiency Tracking Loop
Abstract:
A battery-less, multi-node wireless body area network (WBAN) system-on-a-chip (SoC) is demonstrated. An efficiency tracking loop is proposed that adjusts the rectifier's threshold voltage to maximize the wireless harvesting operation, resulting in a minimum RF sensitivity better than –20 dBm at 904.5 MHz. Each SoC node is injection-locked and time-synchronized with the broadcasted RF basestation power (up to a sensitivity of –33 dBm) using an injection-locked frequency divider (ILFD). Hence, every sensor node is phase-locked with the basestation and all nodes can wirelessly transmit TDMA sensor data concurrently. Designed in a 65 nm-CMOS process, the fabricated sensor SoC contains the energy harvesting rectifier and bandgap, duty-cycled ADC, digital logic, as well as the multi-node wireless clock synchronization and MICS-band transmitter. For a broadcasted basestation power of 20 dBm (30 dBm), experimental measurements verify correct powering, sensor reading, and wireless data transfer for a distance of 3 m (9 m). The entire biomedical system application is verified by reception of room and abdominal temperature monitoring.
Autors: Xia, L.;Cheng, J.;Glover, N.E.;Chiang, P.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jun 2014, volume: 49, issue:6, pages: 1345 - 1355
Publisher: IEEE
 
» 0.6–2.7-Gb/s Referenceless Parallel CDR With a Stochastic Dispersion-Tolerant Frequency Acquisition Technique
Abstract:
A 0.6–2.7-Gb/s phase-rotator-based four-channel digital clock and data recovery (CDR) IC featuring a low-power dispersion-tolerant referenceless frequency acquisition technique is presented. A quasi-periodic reference clock signal extracted directly from a dispersed input signal is distributed to digitally controlled phase rotators in the CDR ICs for phase acquisition. A multiphase frequency acquisition scheme is employed for the reduction of the clock jitter. The measurement results show that the proposed design offers a lower frequency offset and clock noise floor under channel dispersion, as compared with conventional designs. The proposed four-channel digital CDR IC is fabricated in a 90-nm CMOS process. The figure of merit for a single channel is 8 mW/Gb/s such as a feedforward equalizer, a decision-feedback equalizer, and a referenceless CDR.
Autors: Han, J.;Won, H.;Bae, H.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jun 2014, volume: 22, issue:6, pages: 1219 - 1225
Publisher: IEEE
 
» 1-D Large Signal Model of Folded-Waveguide Traveling Wave Tubes
Abstract:
A recently published hybrid circuit model for folded-waveguide slow wave structures has been implemented in the 1-D large signal code CHRISTINE. The resulting code is applied to a design for a G-band (220 GHz) folded-waveguide traveling wave tube. Results of small and large signal gain are compared with those from TESLA, a 2-D code using the same circuit model. Conditions for accuracy of the 1-D model are illustrated and explained. The effects of an offset beam tunnel on circuit dispersion and amplifier stability are illustrated using the CHRISTINE code.
Autors: Chernin, D.;Antonsen, T.M.;Vlasov, A.N.;Chernyavskiy, I.A.;Nguyen, K.T.;Levush, B.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jun 2014, volume: 61, issue:6, pages: 1699 - 1706
Publisher: IEEE
 
» 1.3 μm InGaAlAs asymmetric corrugationpitch- modulated DFB lasers with high mask margin at 28 Gbit/s
Abstract:
Direct modulation of a 1.3 μm InGaAlAs asymmetric corrugationpitch- modulated (ACPM) distributed feedback (DFB) laser operated at 28 Gbit/s was experimentally demonstrated. The laser exhibits linear light??current characteristics and a high-frequency response with a small roll-off at low frequency compared with a conventional λ/4-shifted DFB laser. Moreover, it attains a high mask margin (20%) under 28 Gbit/s operation at 55°C. These superior properties are due to a superior ACPM grating that suppresses longitudinal spatial hole-burning.
Autors: Nakahara, K.;Wakayama, Y.;Kitatani, T.;Fukamachi, T.;Sakuma, Y.;Tanaka, S.;
Appeared in: Electronics Letters
Publication date: Jun 2014, volume: 50, issue:13, pages: 947 - 948
Publisher: IEEE
 
» 100-nm IGZO Thin-Film Transistors With Film Profile Engineering
Abstract:
100-nm indium–gallium–zinc-oxide (IGZO) thin-film transistors were fabricated with a one-mask process, which takes the advantage of photoresist trimming technique and the concept of film profile engineering (FPE). With I-line-based photolithography, a device with channel length of 97 nm has been successfully fabricated. The FPE device contains a conformal gate oxide, concave IGZO channel, and discrete source/drain (S/D) Al contacts. Good device characteristics including a high-ON/OFF current ratio and good subthreshold swing (140 mV/decade) are obtained. Nonetheless, high-S/D series resistance presents a key issue that needs to be addressed for further device performance improvement.
Autors: Lin, H.;Shie, B.;Huang, T.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jun 2014, volume: 61, issue:6, pages: 2224 - 2227
Publisher: IEEE
 
» 14 GSps Four-Bit Noninterleaved Data Converter Pair in 90 nm CMOS With Built-In Eye Diagram Testability
Abstract:
This paper presents the design and test of a 14 GSps, four-bit data converter pair in 90 nm CMOS suitable for implementing advanced serial links. The data converter pair consists of a noninterleaved flash analog-to-digital converter (ADC) and a noninterleaved current-steering digital-to-analog converter (DAC). Both the converter designs adopt the wave-pipelining technique to increase the available signal settling time. Through detailed analysis, we show that cascading three active feedback preamplifiers to implement the cores of the comparators in the ADC balances the power budget and the design difficulty when we push the sampling rate to the process limit. Current mode logic gates are used to alleviate the power bouncing issue. To address the difficulty and high cost of testing the extremely high-speed converters, the design embeds the simple design-for-testability circuits cooperating with the on-chip resources to provide two cost-effective test modes. The first test mode cascades the ADC and DAC so that they can be tested at the rated speed without the need of a very high speed logic analyzer. The second test mode enables the eye diagram tests by shuffling the digital outputs of ADC as the inputs of the DAC instead of adopting conventional linear feedback shift register. The experimental results show that the cascaded ADC and DAC pair achieves a 31.0 dBc spurious-free dynamic range and a 25.9 dB signal-to-noise-and-distortion ratio with a 1.11 GHz, stimulus at 14 GSps. The ADC and DAC consume 214 mW and 85 mW from a 1.0-V supply and occupy 0.1575 and 0.0636 , respectively.
Autors: Hong, H.;Chen, Y.;Fang, W.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jun 2014, volume: 22, issue:6, pages: 1238 - 1247
Publisher: IEEE
 
» 2 2 MIMO OFDM-RoF System Employing LMS-Based Equalizer With I/Q Imbalance Compensation at 60 GHz
Abstract:
Multiple-input–multiple-output (MIMO) technology is a promising method to increase spectral efficiency in wireless communications. In this paper, a 60-GHz orthogonal frequency-division multiplexing radio over fiber (OFDM-RoF) system employing 2 2 MIMO wireless technology is demonstrated. With the proposed equalizer employing least mean squares (LMS) algorithm, MIMO channel mixing and I/Q-mismatch can be compensated simultaneously. 16-QAM and 32-QAM OFDM signal transmissions under forward error correction (FEC) threshold ( ) are demonstrated. A data rate of 76.3 Gb/s can be achieved with a bit-loading algorithm over 25-km fiber transmission and 3.5-m wireless transmission.
Autors: Huang, H.-T.;Shih, P.-T.;Lin, C.-T.;Cheng, Y.-H.;Liang, W.-L.;Ho, C.-H.;Wei, C.-C.;Ng'oma, A.;
Appeared in: IEEE Photonics Journal
Publication date: Jun 2014, volume: 6, issue:3, pages: 1 - 7
Publisher: IEEE
 
» 2 GHz sub-harmonically injectin-locked PLL with mixer-based injection timing control in 0.18 μm CMOS technology
Abstract:
A 2 GHz sub-harmonically injection-locked phase-locked loop (SILPLL) with a self-aligned injection window is presented. The SILPLL adopts a mixer-based self-align technique to automatically adjust the injection timing, overcoming the speed limitation of the phase detection. Circuit techniques such as a symmetrical mixer and a V/I converter with mismatch cancellation are adopted to improve injection timing accuracy. Fabricated in a 180 nm CMOS technology, the SILPLL exhibits -127 dBc/Hz phase noise at 1 MHz offset and draws 6.9 mA current from a 1.8 V power supply. The measured root-mean-square jitter integrating from 1 kHz to 40 MHz is 214 fs and the reference spur is -61 dBc.
Autors: Huang, K.;Wang, Z.;Zheng, X.;Zhang, C.;Wang, Z.;
Appeared in: Electronics Letters
Publication date: Jun 2014, volume: 50, issue:12, pages: 855 - 857
Publisher: IEEE
 
» 2-D–3-D Switchable Gate Driver Circuit for TFT-LCD Applications
Abstract:
This paper presents a novel 2-D–3-D switchable gate driver circuit for active-matrix liquid crystal displays (AMLCDs) applications using the hydrogenated amorphous silicon (a-Si:H) technology. While consisting of 12 thin-film transistors (TFTs), the proposed gate driver circuit includes a pull-up circuit, two alternative circuits, and a key pull-down circuit. To provide a stable output waveform for switching between the 2-D and 3-D modes in AMLCD panel, the proposed circuit can improve the threshold voltage shift of a-Si:H TFT using reversed bias stress. Based on a real circuit integrated on glass with a standard five-mask process applied to a large-sized FHD TFT-LCD panel, the layout area of each gate driver circuit is 359.25 2296.25 . In addition, the power consumption of a 12-stage gate driver circuit is 3.25 and 7.21 mW, while operating at 2-D and 3-D modes, respectively. Measurement results indicate that the output waveform, including output voltage, rising time, and falling time can be stabilized and made almost equal to the initial state after the reliability test at 100 over 240 h.
Autors: Lin, C.;Cheng, M.;Tu, C.;Hung, C.;Li, J.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jun 2014, volume: 61, issue:6, pages: 2098 - 2105
Publisher: IEEE
 
» 2013 MTT-S Graduate Student Fellowship Awards [Education News]
Abstract:
The IEEE Microwave Theory and Techniques Society (MTT-S) Graduate Student Fellowship Awards are sponsored by the MTT-S for the purpose of encouraging and supporting graduate students from around the world interested in pursuing the field of microwave engineering. The graduate fellowship recipients receive an award of US$6,000 to support their research activities, which is presented at the annual IEEE MTT-S International Microwave Symposium (IMS). Supplemental travel funding is offered to the recipients to support their travel to the IMS. Ten graduate fellowships were awarded in 2013 in the general category and three in the medical applications category. In 2013, 25 applications from 12 countries were received in the general category, and eight applications from four countries were received in the medical applications category. The applications were excellent and represented some of the best research being conducted around the world. Even with the additional medical applications award, the success rate was only about 40% due to the large number of submissions. The 13 awardees and their projects are described.
Autors: Crupi, G.;Kaul, R.;Li, C.;Schreurs, D.;
Appeared in: IEEE Microwave Magazine
Publication date: Jun 2014, volume: 15, issue:4, pages: 154 - 158
Publisher: IEEE
 
» 3-D Transient Analysis of TSV-Induced Substrate Noise: Improved Noise Reduction in 3-D-ICs With Incorporation of Guarding Structures
Abstract:
Substrate coupling in 3-D-ICs using Cu through silicon vias (TSVs) is a predicament widely documented in recent literature. Yet, discussions remain limited to the electromagnetic framework, such that a complete understanding of noise propagation and absorption is hampered. This letter thoroughly examines these phenomena in the TSVs from the integrated perspectives of semiconductor physics and electromagnetic theory and investigates the noise reduction method using the combination of p guard-ring and grounded TSV via 3-D device simulation.
Autors: Lin, L.J.;Chiou, Y.;
Appeared in: IEEE Electron Device Letters
Publication date: Jun 2014, volume: 35, issue:6, pages: 660 - 662
Publisher: IEEE
 
» 3C-SiC nanocrystals/TiO2 nanotube heterostructures with enhanced photocatalytic performance
Abstract:
p-type ultrathin 3C-SiC nanocrystals are coated on heat-treated n-type TiO2 nanotube arrays formed by electrochemical etching of Ti sheets to produce heterostructured photocatalysts. Depending on the amounts of 3C-SiC nanocrystals on the TiO2 nanotubes, photocatalytic degradation of organic species can be enhanced. The intrinsic electric field induced by the heterojunction promotes separation of the photoexcited electrons-holes in both the TiO2 nanotubes and 3C-SiC nanocrystals. Hence, holes can more effectively travel to the surface of 3C-SiC nanocrystals and there are more electrons on the surface of TiO2 nanotubes consequently forming more O2 and OH species to degrade organic molecules.
Autors: Zhang, J.;Liu, L.Z.;Yang, L.;Gan, Z.X.;Wu, X.L.;Chu, Paul K.;
Appeared in: Applied Physics Letters
Publication date: Jun 2014, volume: 104, issue:23, pages: 231902 - 231902-4
Publisher: IEEE
 
» 3D Integration Using Self-Assembly at Air-Water-Solid Interface
Abstract:
This paper presents the first proof-of-concept 3D integration using fluidic self-assembly of chip-scale parts (2000 2000 100 ) at an air-water-solid interface. Four-layer 3D integration is achieved by assembling new parts over previously assembled parts. Assembly proceeds as an assembly substrate is pulled up through an air-water interface and electrical and mechanical bonding are achieved by solder reflow. Magnetic fields and temporary Faraday waves are introduced for one-to-one part-to-site registration in proper orientation. The alignment accuracy degrades with increasing number of layers due to weaker magnetic force. The maximum number of layers that can be achieved is simulated and analyzed. Via resistance including the effect of degradation of solder over repeated reflow process is measured.
Autors: Park, K.S.;Varel, C.;Hoo, J.H.;Baskaran, R.;Bohringer, K.F.;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Jun 2014, volume: 23, issue:3, pages: 579 - 584
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: Jun 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: Jun 2014, volume: 34, issue:3, pages: 30 - 38
Publisher: IEEE
 
» 3D Visual Discomfort Prediction: Vergence , Foveation, and the Physiological Optics of Accommodation
Abstract:
To achieve clear binocular vision, neural processes that accomplish accommodation and vergence are performed via two collaborative, cross-coupled processes: accommodation-vergence (AV) and vergence-accommodation (VA). However, when people watch stereo images on stereoscopic displays, normal neural functioning may be disturbed owing to anomalies of the cross-link gains. These anomalies are likely the main cause of visual discomfort experienced when viewing stereo images, and are called Accommodation-Vergence Mismatches (AVM). Moreover, the absence of any useful accommodation depth cues when viewing 3D content on a flat panel (planar) display induces anomalous demands on binocular fusion, resulting in possible additional visual discomfort. Most prior efforts in this direction have focused on predicting anomalies in the AV cross-link using measurements on a computed disparity map. We further these contributions by developing a model that accounts for both accommodation and vergence, resulting in a new visual discomfort prediction algorithm dubbed the 3D-AVM Predictor. The 3D-AVM model and algorithm make use of a new concept we call local 3D bandwidth (BW) which is defined in terms of the physiological optics of binocular vision and foveation. The 3D-AVM Predictor accounts for anomalous motor responses of both accommodation and vergence, yielding predictive power that is statistically superior to prior models that rely on a computed disparity distribution only.
Autors: Park, J.;Lee, S.;Bovik, A.C.;
Appeared in: IEEE Journal of Selected Topics in Signal Processing
Publication date: Jun 2014, volume: 8, issue:3, pages: 415 - 427
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: Jun 2014, volume: 34, issue:3, pages: 50 - 58
Publisher: IEEE
 
» 3DOM: A 3 Degree of Freedom Manipulandum to Investigate Redundant Motor Control
Abstract:
This paper presents a novel robotic interface to investigate the neuromechanical control of redundant planar arm movements. A unique aspect of this device is the third axis by which the wrist, and hence the pose of the arm can be fully constrained. The topology is based on a 5R, closed loop pantograph, with a decoupled wrist flexion/extension cable actuated mechanism. The design and characterization (in terms of range of motion, impedance, friction and dynamics) are described in this paper. This device is lightweight, safe and has high force capabilities and low impedance. Simple experiments illustrate the advantages of this device for the investigation of redundant motor control in humans.
Autors: Klein, J.;Roach, N.;Burdet, E.;
Appeared in: IEEE Transactions on Haptics
Publication date: Jun 2014, volume: 7, issue:2, pages: 229 - 239
Publisher: IEEE
 
» 400-A (Pulsed) Vertical GaN p-n Diode With Breakdown Voltage of 700 V
Abstract:
There is a great interest in monolithic GaN semiconductor devices with high current capability for power electronics. In this letter, large area vertical GaN p-n diodes fabricated on bulk GaN substrates are discussed. Diodes with areas as large as 16 with breakdown voltages exceeding 700 V and pulsed (100 ) currents approaching 400 A are reported. This is made possible for the first time in part due to the recent availability of improved quality bulk GaN substrates.
Autors: Kizilyalli, I.C.;Edwards, A.P.;Nie, H.;Bui-Quang, P.;Disney, D.;Bour, D.;
Appeared in: IEEE Electron Device Letters
Publication date: Jun 2014, volume: 35, issue:6, pages: 654 - 656
Publisher: IEEE
 
» 45-nm CMOS SOI Technology Characterization for Millimeter-Wave Applications
Abstract:
This paper presents an in-depth study of a 45-nm CMOS silicon-on-insulator (SOI) technology. Several transistor test cells are characterized and the effect of finger width, gate contact, and gate poly pitch on transistor performance is analyzed. The measured peak is 264 GHz for a 30 1007 nm single-gate contact relaxed-pitch transistor and the best of 283 GHz is achieved by a 58 513 nm single-gate contact regular pitch transistor. The measured transistor performance agrees well with the simulations including R/C extraction up to the top metal layer. Passive components are also characterized and their performance is predicted accurately with design kit models and electromagnetic simulations. Low-noise amplifiers from - to -band are developed in this technology and they achieve state-of-the-art noise-figure values.
Autors: Inac, O.;Uzunkol, M.;Rebeiz, G.M.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jun 2014, volume: 62, issue:6, pages: 1301 - 1311
Publisher: IEEE
 
» 500 MHz OOK Transmitter With 22 pj/bit, 38.4% Efficiency Using RF Current Combining
Abstract:
A 500 MHz On-Off Keying (OOK) transmitter integrated with a high-efficiency wideband power amplifier (PA) is designed for low-power/high-data rate applications. The PA biased in Class C region, employs a bias current-reused and an RF current-combining structure to achieve a high-efficiency and high-data rate. The transmitter is fabricated using a 0.13 m CMOS process. The chip size is 0.6 mm and the measured drain efficiency of the PA reaches 59.5% at 500 MHz with 1.62 dBm output power while consuming only 2.52 mW dc power from a 3 V power supply. The efficiency of the transmitter is 38.4% and the energy usage is 22 pJ/bit at a data rate of 100 Mbps with dBm average output power.
Autors: Kim, K.;Choi, J.;Seo, M.;Nam, S.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jun 2014, volume: 24, issue:6, pages: 424 - 426
Publisher: IEEE
 
» 900 V/1.6 Normally Off MOSFET on Silicon Substrate
Abstract:
In this paper, we report the device performance of a high-voltage normally off MOSFET on the Si substrate. Normally off operation is obtained by multiple cycles of plasma oxidation and wet oxide-removal gate recess process. The recessed normally off GaN MOSFET with 3 gate-drain distance exhibits a maximum drain current of 585 mA/mm at 9 V gate bias. The threshold voltage of the MOSFET is 2.8 V with a standard derivation of 0.2 V on the sample with an area of 2 2 . The gate leakage current is below during the whole gate swing up to 9 V and the ratio is larger than , indicating the good quality of gate insulator. The MOSFET with 10 gate-drain distance shows a three terminal OFF-state breakdown voltage (BV) of 967 V at zero gate-source bias with a drain leakage current criterion of 1 . The specific ON-resistance of the device is 1.6 ${rm m}Omega,{cdot},{rm cm}^{2}$ and the power figure of merit is 584 .
Autors: Wang, M.;Wang, Y.;Zhang, C.;Xie, B.;Wen, C.P.;Wang, J.;Hao, Y.;Wu, W.;Chen, K.J.;Shen, B.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jun 2014, volume: 61, issue:6, pages: 2035 - 2040
Publisher: IEEE
 
» -RAID: Parallel RAID Architecture for Fast Data Recovery
Abstract:
As disk volume grows rapidly with terabyte disk becoming a norm, RAID reconstruction process in case of a failure takes prohibitively long time. This paper presents a new RAID architecture, -RAID, allowing the disk array to reconstruct very quickly in case of a disk failure. The idea is to form skewed sub-arrays in the RAID structure so that reconstruction can be done in parallel dramatically speeding up data reconstruction process and hence minimizing the chance of data loss. We analyse the data recovery ability of this architecture and show its good scalability. A prototype -RAID system has been built and implemented in the Linux operating system for the purpose of evaluating its performance potential. Real world I/O traces including SPC, Microsoft, and a collection of a production environment have been used to measure the performance of -RAID as compared to existing baseline software RAID5, Parity Declustering, and RAID50. Experimental results show that our new -RAID speeds up data reconstruction time by a factor 2 to 4 compared to the traditional RAID. Meanwhile, -RAID keeps comparable production performance to that of the baseline RAID layouts while online RAID reconstruction is in progress.
Autors: Wan, J.;Wang, J.;Xie, C.;Yang, Q.;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jun 2014, volume: 25, issue:6, pages: 1638 - 1647
Publisher: IEEE
 
» -Boosted Complementary Current-Reuse Colpitts VCO With Low Power and Low Phase Noise
Abstract:
In this letter, a transformer-based current-reuse Colpitts voltage controlled oscillator (VCO) is proposed, which combines a N-type and P-type Colpitts oscillators using a 5-port transformer in a complementary form to provide the differential outputs. The proposed VCO has low phase noise due to the low noise Colpitts oscillator topology and the negative- boosting technique with half of the DC-current consumption using the current-reusing method. The proposed VCO has the frequency tuning range from 8.57 to 10.21 GHz, and shows low phase noise of at 1 MHz offset frequency at 9.41 GHz and high figure of merit with tuning range ( ) of . The power consumption is 2.1 mW from 1.2 V supply voltage. The VCO is implemented using 0.13 CMOS process with chip area of 0.45 .
Autors: Ha, K.-W.;Ryu, H.;Lee, J.-H.;Kim, J.-G.;Baek, D.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jun 2014, volume: 24, issue:6, pages: 418 - 420
Publisher: IEEE
 
» -Band Multiple Feed per Beam Focal Array Using Interleaved Couplers
Abstract:
In this paper, an original focal array for multibeam antenna is presented. It is based on multiple feed per beam (MFB) geometry. Each beam is produced by a cluster of feed horns illuminating a parabolic reflector. Three adjacent clusters of the focal array overlap for enhancing the illumination performance within the size-constrained array lattice. The beam-forming network is the key component and drives the overall performances of the radiating structure. It is composed of tri-dimensional interleaved couplers made of circular waveguides and interconnected by thin radial rectangular waveguides. The design, manufacturing, and measurement of a -band MFB focal array are reported. It is composed of 31 feed horns displayed in seven clusters, for a global size of about , where denotes the free-space wavelength at the lowest operating frequency. The realized gain is higher by than the gain provided by the single feed per beam focal array having analogous size.
Autors: Leclerc, C.;Romier, M.;Aubert, H.;Annabi, A.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jun 2014, volume: 62, issue:6, pages: 1322 - 1329
Publisher: IEEE
 
» Performance Evaluation of Interconnect Architecture Options Beyond the 10-nm Logic Node
Abstract:
This paper summarizes the findings of an performance modeling approach for evaluating various material and architecture options by which interconnect wires are incorporated onto integrated circuits. For the present dual-damascene structure, the grain boundary and surface scattering modes are identified as the top contributors to resistance degradation, along with the cross-sectional area consumed by the liner/barrier layers. Self-forming barriers, a technology that provides direct Cu-insulator interfaces, would quench surface scattering and provide larger cross-sectional area for the conductor in the wire. In addition, if engineered to be thinner than 1.5 nm, they would not negatively impact capacitance. This new architecture also allows for replacing low- dielectric fill with air-gap incorporation, further enhancing the capacitance component of the delay. This proposed new scheme is shown to deliver the -related performance metrics set by the International Technology Roadmap for Semiconductors. Other conductor possibilities, such as Co and W, are also evaluated along with subtractive metal processing options.
Autors: Kincal, S.;Abraham, M.C.;Schuegraf, K.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jun 2014, volume: 61, issue:6, pages: 1914 - 1919
Publisher: IEEE
 
» Wi-Fi: A Mechanism to Achieve Energy Efficient Discovery in Wi-Fi
Abstract:
Wi-Fi has enjoyed since its conception a striking success as a technology to access the Internet. Thus, Wi-Fi is today embedded in most of our portable devices like smartphones and tablets. Leveraging the ubiquity and mobility of Wi-Fi devices, in this paper we study how to expand current Wi-Fi implementations in order to design a mechanism that allows mobile devices to advertise and discover small chunks of information in an energy efficient way, even in crowded environments. We refer to this mechanism as Energy Efficient Discovery ( ) Wi-Fi. Our contribution in this paper is twofold. First, we present the design of Wi-Fi as a set of driver level extensions to current Wi-Fi implementations, which can de deployed with just a firmware upgrade, and that focus on discovery, synchronization and channel access. Second, we present a thorough performance evaluation based on packet level simulations that demonstrates the performance to be expected from Wi-Fi in realistic scenarios.
Autors: Camps-Mur, D.;Loureiro, P.;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Jun 2014, volume: 13, issue:6, pages: 1186 - 1199
Publisher: IEEE
 
» -Over- Multidimensional Position Modulation
Abstract:
We analyze a family of modulation formats based on multidimensional position modulation (MDPM) with multiple pulses per frame ( -over- -MDPM) in combination with quadrature phase shift keying (QPSK), polarization multiplexed QPSK (PM-QPSK) and polarization-switched QPSK (PS-QPSK) for coherent communication systems. MDPM is a generalization of pulse position modulation where different pulse slots can be realized by time slots, polarization states, frequencies, modes of multimode fibers, cores in multicore fibers or a combination of these. We show that by using -over- -MDPM with QPSK, it is possible to simultaneously increase both the spectral efficiency and the asymptotic power efficiency over QPSK. We also identify -ary inverse-MDPM ( iMDPM-QPSK) as the special case of -over-( )-MDPM and show that 4iMDPM-QPSK has a 1.25 dB increased asymptotic power efficiency over QPSK with a maintained spectral efficiency.
Autors: Eriksson, T.A.;Johannisson, P.;Puttnam, B.J.;Agrell, E.;Andrekson, P.A.;Karlsson, M.;
Appeared in: Journal of Lightwave Technology
Publication date: Jun 2014, volume: 32, issue:12, pages: 2254 - 2262
Publisher: IEEE
 
» ?I? Also Stands for Innovation and Industry [Message from the President]
Abstract:
Autors: Hung, J.;
Appeared in: IEEE Industrial Electronics Magazine
Publication date: Jun 2014, volume: 8, issue:2, pages: 3 - 5
Publisher: IEEE
 
» A 0.5-V P-Well/Deep N-Well Photodetector in 65-nm CMOS for Monolithic 850-nm Optical Receivers
Abstract:
This letter presents the design, measurement results, and modeling formula of a P-well/deep N-well photodetector (PD) realized in a standard 65-nm complementary metal-oxide-semiconductor without process modification. With 0.5-V reverse bias (VPD), the measured dc responsivity to an 850-nm light source is 51 mA/W and the −3-dB bandwidth is 500 MHz. Besides, a seamless cosimulation of the PD and the following receiver circuits are presented. Optical measurement results show that under 0.5-V VPD, the optical receiver achieves a new record data rate of 9 Gb/s for 215−1 pseudorandom binary sequence with 10−12 bit error rate and −4.2-dBm optical input sensitivity.
Autors: Pan, Q.;Hou, Z.;Li, Y.;Poon, A.W.;Yue, C.P.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jun 2014, volume: 26, issue:12, pages: 1184 - 1187
Publisher: IEEE
 
» A 10 bit, 300 MS/s Nyquist Current-Steering Power DAC With 6 V Output Swing
Abstract:
A 10 bit current-steering, digital-to-analog converter (DAC) is presented that delivers 6 V into a 100 Ω differential load. To realize high-voltage swings using fineline CMOS, a stacked-FET buffer is used to isolate the current source from the output load. The stacked-FET buffer degrades the linearity of the DAC. This work presents a Volterra analysis to capture the frequency-dependent behavior of the stacked-FET circuit that can be cascaded to quantify the linearity of an -device stack. The power DAC is implemented in 45 nm CMOS SOI and the measured differential nonlinearity (DNL) and integral nonlinearity (INL) is better than 0.4 and 0.6 LSB, respectively. The DAC consumes 476 mW and achieves a peak SFDR of 73 dB and a minimum IM3 of 69 dBc. This DAC demonstrates the largest output swing and highest power efficiency for a high-resolution ( 8 bit), high-speed ( 100 MS/s) DAC.
Autors: Mehrjoo, M.S.;Buckwalter, J.F.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jun 2014, volume: 49, issue:6, pages: 1408 - 1418
Publisher: IEEE
 
» A 100-kS/s 8.3-ENOB 1.7- Time-Domain Analog-to-Digital Converter
Abstract:
A 100-kS/s time-domain analog-to-digital converter (TDADC) with successive approximation register architecture provides 8.3 effective bits. The time-domain comparator of the TDADC is realized with only one delay line consisting of a digitally controlled delay line and a voltage-controlled delay line. Therefore, the linearity degradation due to the mismatch between multiple delay lines can be avoided. The TDADC has been implemented in a 0.11- CMOS process with a 0.127- active silicon area. The TDADC consumes 1.7 from a 0.6-V supply voltage.
Autors: Kim, Y.;Yoo, C.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jun 2014, volume: 61, issue:6, pages: 408 - 412
Publisher: IEEE
 
» A 12 bit 200 MS/s Zero-Crossing-Based Pipelined ADC With Early Sub-ADC Decision and Output Residue Background Calibration
Abstract:
A 12 bit 200 MS/s analog-to-digital converter (ADC) applies techniques of zero-crossing-based circuits as a replacement for high-gain high-speed op-amps. High accuracy in the residue amplifier is achieved by using a coarse phase in ZCBC followed by a level-shifting capacitor for fine phase. Sub-ADC flash comparators are strobed immediately after the coarse phase to achieve a high sampling rate. The systematic offset voltage between the coarse and fine phase manifests itself as systematic offset in the sub-ADC comparators. This offset is caused by the coarse phase undershoot and the fine phase overshoot. In this work, the offset is cancelled with background calibration by residue range correction circuits in the following stage's sub-ADC. In addition, the sub-ADC's random comparator offset is calibrated with a discrete-time charge-pump based background calibration technique. The reference buffer, bias circuitry, and digital error correction circuits are all integrated on a single chip. The ADC occupies an area of 0.282 mm in 55 nm CMOS technology and dissipates 30.7 mW. It achieves 64.6 dB SNDR and 82.9 dBc SFDR at 200 MS/s for a FOM of 111 fJ/conversion-step. The SNDR degrades gracefully above the designed sampling frequency to 62.9 dB at 250 MS/s, and remains above 50 dB at 300 MS/s.
Autors: Shin, S.-K.;Rudell, J.C.;Daly, D.C.;Munoz, C.E.;Chang, D.-Y.;Gulati, K.;Lee, H.-S.;Straayer, M.Z.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jun 2014, volume: 49, issue:6, pages: 1366 - 1382
Publisher: IEEE
 
» A 13.56 MHz CMOS Active Rectifier With Switched-Offset and Compensated Biasing for Biomedical Wireless Power Transfer Systems
Abstract:
A full-wave active rectifier switching at 13.56 MHz with compensated bias current for a wide input range for wirelessly powered high-current biomedical implants is presented. The four diodes of a conventional passive rectifier are replaced by two cross-coupled PMOS transistors and two comparator- controlled NMOS switches to eliminate diode voltage drops such that high voltage conversion ratio and power conversion efficiency could be achieved even at low AC input amplitude . The comparators are implemented with switched-offset biasing to compensate for the delays of active diodes and to eliminate multiple pulsing and reverse current. The proposed rectifier uses a modified CMOS peaking current source with bias current that is quasi-inversely proportional to the supply voltage to better control the reverse current over a wide AC input range (1.5 to 4 V). The rectifier was fabricated in a standard 0.35 CMOS N-well process with active area of 0.0651 . For the proposed rectifier measured at , the voltage conversion ratios are 0.89 and 0.93 for and 5 , respectively, and the measured power conversion efficiencies are 82.2% to 90.1% with ranges from 1.5 to 4 V for .
Autors: Lu, Y.;Ki, W.-H.;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Jun 2014, volume: 8, issue:3, pages: 334 - 344
Publisher: IEEE
 
» A 132-dB Dynamic-Range Global-Shutter Stacked Architecture for High-Performance Imagers
Abstract:
This brief presents a global-shutter imager readout architecture that allows a dynamic range (DR) of more than 132 dB and a high frame rate. It is based on a stacked technology where the top tier contains the back-illuminated pixel array, and the bottom tier contains the subpixel logic array, which implements the dynamic-range extension by selecting the best integration time for each pixel. Experimental results of a 64 64 subpixel array confirm the effectiveness of the proposed method in extending the DR by more than 10 bits. The application of the algorithm to higher array resolutions compromises its effectiveness given the increased column capacitance. As a way out, we propose a novel source-follower-based buffer that reduces the settling time of the subpixel without increasing its size. The performed analysis shows that the sensor can reach 1900 and 375 fps, respectively, at full HD and at 8-K resolutions.
Autors: Xhakoni, A.;Gielen, G.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jun 2014, volume: 61, issue:6, pages: 398 - 402
Publisher: IEEE
 
» A 14 kW High-Power X-Band to Ka-Band Klystron Frequency Multiplier
Abstract:
This paper reports the development of an X-band to Ka-band klystron frequency multiplier that can triple the input frequency and amplify the input power simultaneously. A 7-cavity klystron was designed, in which the X-band output section was replaced by a smaller Ka-band one. The electron optics of this new klystron was nearly the same as that of an X-band klystron. The experimental results showed that a peak output power of 14 kW can be reached at a pulse voltage of 36 kV, with an efficiency of 3.9%.
Autors: Fan, J.;Wang, Y.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jun 2014, volume: 61, issue:6, pages: 1854 - 1858
Publisher: IEEE
 
» A 160-GHz Frequency-Translation Phase-Locked Loop With RSSI Assisted Frequency Acquisition
Abstract:
A 160-GHz frequency-translation PLL with tuning range from 156.4 GHz to 159.2 GHz is presented. Sub-THz 1/9 prescaler is replaced by a 3rd harmonic mixer incorporating a frequency tripler for frequency down conversion. A transformer-based VCO is utilized to alleviate capacitive and resistive load associated with varactor and succeeding buffer stages. Frequency acquisition is assisted by received signal strength indicator (RSSI) for automatic frequency sweeping and fast locking. Fabricated in 65 nm CMOS technology, the chip size is 0.92 . The PLL locking time is less than 3 . This chip drains 24 mW from a 1.2 V power supply.
Autors: Chen, W.-Z.;Lu, T.-Y.;Wang, Y.-T.;Jian, J.-T.;Yang, Y.-H.;Chang, K.-T.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jun 2014, volume: 61, issue:6, pages: 1648 - 1655
Publisher: IEEE
 
» A 2.4 GHz ZigBee Receiver Exploiting an RF-to-BB-Current-Reuse Blixer + Hybrid Filter Topology in 65 nm CMOS
Abstract:
A 2.4 GHz ZigBee receiver unifying a balun-LNA-I/Q-mixer (Blixer) and a baseband (BB) hybrid filter in one cell is fabricated in 65 nm CMOS. Without any external components, wideband input matching and passive pre-gain are concurrently achieved via co-optimizing an integrated low-Q network with a balun-LNA. The latter also features active-gain boosting and partial-noise canceling to enhance the gain and noise figure (NF). Above the balun-LNA are I/Q double-balanced mixers driven by a 4-phase 25% LO for downconversion and gain-phase balancing. The generated BB currents are immediately filtered by an IF-noise-shaping current-mode Biquad and a complex-pole load, offering first-order image rejection and third-order channel selection directly atop the Blixer. Together with other BB and LO circuitries, the receiver measures 8.5 dB NF, 57 dB gain and 6-dBm IIP3 at 1.7 mW power and 0.24 mm die size. The S -bandwidth ( 10 dB) covers 2.25 to 3.55 GHz being robust to packaging variations. Most performance metrics compare favorably with the state-of-the-art.
Autors: Lin, Z.;Mak, P.-I.;Martins, R.P.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jun 2014, volume: 49, issue:6, pages: 1333 - 1344
Publisher: IEEE
 
» A 20-ps Time-to-Digital Converter (TDC) Implemented in Field-Programmable Gate Array (FPGA) with Automatic Temperature Correction
Abstract:
This paper presents an automatic temperature correction design for carry chain based time-to-digital converter (TDC) in field-programmable gate array (FPGA). The bin-by-bin calibrations under different temperatures are performed for both plain TDC and Wave Union TDC to characterize the influence of temperature variation on the delay time of carry chain. Accordingly, a simplified temperature correction scheme by using a dedicated correction channel to measure the coefficient and correct fine time result for all TDC channels is implemented and tested. This method shows only few picosecond errors for both simulation and measurement. With this correction approach, a TDC precision of 21 ps has been achieved in Cyclone II FPGA under a wide ambient temperature range from 0 to 60 . Several design key points are also described in this paper.
Autors: Pan, W.;Gong, G.;Li, J.;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Jun 2014, volume: 61, issue:3, pages: 1468 - 1473
Publisher: IEEE
 
» A 4-Element Phased-Array System With Simultaneous Spatial- and Frequency-Domain Filtering at the Antenna Inputs
Abstract:
To reject strong interference in excess of 0 dBm, a 4- element LO-phase shifting phased-array receiver with 8-phase passive mixers terminated by baseband capacitors is presented. The passive mixers upconvert both the spatial and frequency domain filtering from baseband to RF, hence realizing blocker suppression directly at the antenna inputs. A comprehensive mathematical model provides a set of closed-form equations describing the spatial and frequency domain filtering including imperfections. A prototype is realized in 28 nm CMOS. It exploits third harmonic reception to achieve a wide RF-frequency range from 0.6–4.5 GHz at 34–119 mW power dissipation, while also providing impedance matching. Out of the band/beam, a 1 dB-compression point as high as +12/+10 dBm has been measured. The 1-element noise figure over the RF-frequency range is 4–6.3 dB, while in-beam/band IIP3 values of 0– +2.6 dBm are measured. This proposed technique can be instrumental to make RF receivers more robust for interference, while still being flexibly tunable in frequency.
Autors: Ghaffari, A.;Klumperink, E.A.M.;van Vliet, F.;Nauta, B.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Jun 2014, volume: 49, issue:6, pages: 1303 - 1316
Publisher: IEEE
 
» A 515 nW, 0–18 dB Programmable Gain Analog-to-Digital Converter for In-Channel Neural Recording Interfaces
Abstract:
This paper presents a low-area low-power Switched-Capacitor (SC)-based Programmable-Gain Analog-to-Digital Converter (PG-ADC) suitable for in-channel neural recording applications. The PG-ADC uses a novel implementation of the binary search algorithm that is complemented with adaptive biasing techniques for power saving. It has been fabricated in a standard CMOS 130 nm technology and only occupies . The PG-ADC has been optimized to operate under two different sampling modes, 27 kS/s and 90 kS/s. The former is tailored for raw data conversion of neural activity, whereas the latter is used for the on-the-fly feature extraction of neural spikes. Experimental results show that, under a voltage supply of 1.2 V, the PG-ADC obtains an ENOB of 7.56 bit (8-bit output) for both sampling modes, regardless of the gain setting. The amplification gain can be programmed from 0 to 18 dB. The power consumption of the PG-ADC at 90 kS/s is with a FoM of 89.49 fJ/conv, whereas at 27 kS/s it consumes 515 nW and obtains a FoM of 98.31 fJ/conv .
Autors: Rodriguez-Perez, A.;Delgado-Restituto, M.;Medeiro, F.;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Jun 2014, volume: 8, issue:3, pages: 358 - 370
Publisher: IEEE
 
» A 6.4-Gb/s Voltage-Mode Near-Ground Receiver With a One-Tap Data and Edge DFE
Abstract:
A low-power receiver with a one-tap data and edge decision-feedback equalizer (DFE) and a clock recovery circuit is presented. The receiver employs analog adders for the tap-weight summation in both the data and the edge path to simultaneously optimize both the voltage and timing margins. A switched-capacitor input stage allows the receiver to be fully compatible with near-GND input levels without extra level conversion circuits. Furthermore, the critical path of the DFE is simplified to relax the timing margin. Fabricated in the 65-nm CMOS technology, a prototype DFE receiver shows that the data-path DFE extends the voltage and timing margins from 40 and 0.3 unit interval (UI), respectively, to 70 and 0.6 UI, respectively. Likewise, the edge-path equalizer reduces the uncertain sampling region (the edge region), which results in 17% reduction of the recovered clock jitter. The DFE core, including adders and samplers, consumes 1.1 mW from a 1.2-V supply while operating at 6.4 Gb/s.
Autors: Kim, S.;Jin, E.;Kwon, K.;Kim, J.;Chun, J.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jun 2014, volume: 61, issue:6, pages: 438 - 442
Publisher: IEEE
 
» A 60-dB Gain OTA Operating at 0.25-V Power Supply in 130-nm Digital CMOS Process
Abstract:
This paper presents a 60-dB gain bulk-driven Miller OTA operating at 0.25-V power supply in the 130-nm digital CMOS process. The amplifier operates in the weak-inversion region with input bulk-driven differential pair sporting positive feedback source degeneration for transconductance enhancement. In addition, the distributed layout configuration is used for all the transistors to mitigate the effect of halo implants for higher output impedance. Combining these two approaches, we experimentally demonstrate a high gain of over 60-dB with just 18-nW power consumption from 0.25-V power supply. The use of enhanced bulk-driven differential pair and distributed layout can help overcome some of the constraints imposed by nanometer CMOS process for high performance analog circuits in weak inversion region.
Autors: Ferreira, L.H.C.;Sonkusale, S.R.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jun 2014, volume: 61, issue:6, pages: 1609 - 1617
Publisher: IEEE
 
» A 90 nm-CMOS IR-UWB BPSK Transmitter With Spectrum Tunability to Improve Peaceful UWB-Narrowband Coexistence
Abstract:
A new ultra wideband (UWB) pulse generator covering a –10 dB bandwidth of 2.4–4.6 GHz with a tunable center frequency of 5–5.6 GHz to mitigate coexistence issues of impulse radio UWB (IR-UWB) systems and IEEE802.11.a WLAN or other narrowband (NB) systems in 90 nm-CMOS technology is proposed. The UWB pulse is generated based on frequency up-conversion of the first derivative of the Gaussian pulse, which creates an adjustable null in the frequency spectrum. Simulation results show that employing the proposed pulse generator mitigates the mutual interference between UWB and WLAN systems, significantly. The proposed transmitter consists of a low frequency signal generator, an LC oscillator and a mixer, whose output directly drives the antenna using a matching on-chip transformer. Two control signals change the bandwidth and center frequency of the transmitted spectrum depending on the NB frequency and considering process, supply voltage and temperature (PVT) variations. A fast start-up circuit is used in the LC oscillator using current pulse injection and together with the mixer is duty cycled to reduce the power consumption. Post-layout simulation results show a null depth of 23 dB for a null bandwidth of 100 MHz. The energy/pulse and energy/pulse normalized to the output voltage amplitude are 14.4 pJ/pulse and 35.7 pJ/(pulse-V) from a 1-V supply for a pulse rate of 860 Mpulse/s with an active circuit area of only 0.18 mm².
Autors: Mir-Moghtadaei, S.V.;Fotowat-Ahmady, A.;Nezhad, A.Z.;Serdijn, W.A.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jun 2014, volume: 61, issue:6, pages: 1836 - 1848
Publisher: IEEE
 
» A boron nitride nanotube peapod thermal rectifier
Abstract:
The precise guidance of heat from one specific location to another is paramount in many industrial and commercial applications, including thermal management and thermoelectric generation. One of the cardinal requirements is a preferential conduction of thermal energy, also known as thermal rectification, in the materials. This study introduces a novel nanomaterial for rectifying heat—the boron nitride nanotube peapod thermal rectifier. Classical non-equilibrium molecular dynamics simulations are performed on this nanomaterial, and interestingly, the strength of the rectification phenomenon is dissimilar at different operating temperatures. This is due to the contingence of the thermal flux on the conductance at the localized region around the scatterer, which varies with temperature. The rectification performance of the peapod rectifier is inherently dependent on its asymmetry. Last but not least, the favourable rectifying direction in the nanomaterial is established.
Autors: Loh, G.C.;Baillargeat, D.;
Appeared in: Journal of Applied Physics
Publication date: Jun 2014, volume: 115, issue:24, pages: 243501 - 243501-8
Publisher: IEEE
 
» A boson interaction model for electrostatic stresses
Abstract:
Maxwell's stress equation for electrostatics identifies a tensile stress in the direction of the electric field and a pressure normal to this direction. For an isolated, spherically symmetric static charge distribution, Maxwell's stress equation may be recast to eliminate the stress normal to the electric field and establish a stress only aligned with the electric field. The remaining stress is identified as an external omnidirectional Poincar?? stress, inwardly directed towards the charge distribution. The Poincar?? stress is modeled as a mean valued, continual exchange of bosons between the charge distribution and the distant matter of the universe. For two separated, spherically symmetric static charge distributions, Maxwell's stress equation may be recast to develop a line stress that only exists on the straight path between the two charge distributions. The line stress is identified as a Coulomb stress modeled as a mean valued, continual exchange of photons back and forth between two like-charge distributions.
Autors: Minteer, T.M.;
Appeared in: IEEE Transactions on Dielectrics and Electrical Insulation
Publication date: Jun 2014, volume: 21, issue:3, pages: 973 - 981
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: Jun 2014, volume: 34, issue:3, pages: 12 - 18
Publisher: IEEE
 
» A Broadband Implantable and a Dual-Band On-Body Repeater Antenna: Design and Transmission Performance
Abstract:
The design of a new miniature broadband implantable antenna and a dual-band on-body antenna are presented along with the transmission performance between the two. The former and latter antennas are intended for integration into implantable medical devices (IMDs) and on-body repeaters, respectively. The on-body repeater antenna favors the use of very low power IMDs. The on-body repeater receives low power data from an IMD (MedRadio band, 401–406 MHz) and retransmits it to remote devices placed further apart (ISM band, 2400–2480 MHz ). The MedRadio implantable antenna maintains miniature size (399 mm ), and exhibits two close resonances which increase the 10 dB bandwidth inside muscle tissue (87 MHz). The on-body antenna is relatively small (6720 mm ), and exhibits dual resonances in the MedRadio and ISM bands. Assuming a typical arm implantation scenario and an on-body receiver sensitivity of 75 dBm, the proposed configuration is found to enable reduction of the IMD power by a factor of 100. Patient safety and tolerance to electromagnetic interference are, thus, preserved, and lifetime of the IMD is increased. The setup is, finally, shown to be robust to antenna misalignment and polarization rotation.
Autors: Kiourti, A.;Costa, J.R.;Fernandes, C.A.;Nikita, K.S.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jun 2014, volume: 62, issue:6, pages: 2899 - 2908
Publisher: IEEE
 
» A bubble detection system for propellant filling pipeline
Abstract:
This paper proposes a bubble detection system based on the ultrasound transmission method, mainly for probing high-speed bubbles in the satellite propellant filling pipeline. First, three common ultrasonic detection methods are compared and the ultrasound transmission method is used in this paper. Then, the ultrasound beam in a vertical pipe is investigated, suggesting that the width of the beam used for detection is usually smaller than the internal diameter of the pipe, which means that when bubbles move close to the pipe wall, they may escape from being detected. A special device is designed to solve this problem. It can generate the spiral flow to force all the bubbles to ascend along the central line of the pipe. In the end, experiments are implemented to evaluate the performance of this system. Bubbles of five different sizes are generated and detected. Experiment results show that the sizes and quantity of bubbles can be estimated by this system. Also, the bubbles of different radii can be distinguished from each other. The numerical relationship between the ultrasound attenuation and the bubble radius is acquired and it can be utilized for estimating the unknown bubble size and measuring the total bubble volume.
Autors: Wen, Wen;Zong, Guanghua;Bi, Shusheng;
Appeared in: Review of Scientific Instruments
Publication date: Jun 2014, volume: 85, issue:6, pages: 065106 - 065106-7
Publisher: IEEE
 
» A Butterfly Substrate Integrated Waveguide Leaky-Wave Antenna
Abstract:
A new leaky-wave antenna taking advantage of substrate integrated waveguide technology has been introduced. This antenna has a butterfly-like configuration consisting of eight wings, i.e., eight parts. By this configuration, better gain and side-lobe level for lower elevation angles (12 –45 ) are obtained while in the uniform design, these angles were scanned with poor radiation performances. Besides, an effective matching part for good impedance matching has been employed. The simulated data have been compared with measurement results and showed good consistency.
Autors: Mohtashami, Y.;Rashed-Mohassel, J.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jun 2014, volume: 62, issue:6, pages: 3384 - 3388
Publisher: IEEE
 
» A Case for Specialized Processors for Scale-Out Workloads
Abstract:
Emerging scale-out workloads need extensive amounts of computational resources. However, datacenters using modern server hardware face physical constraints in space and power, limiting further expansion and requiring improvements in the computational density per server and in the per-operation energy. Continuing to improve the computational resources of the cloud while staying within physical constraints mandates optimizing server efficiency. In this work, we demonstrate that modern server processors are highly inefficient for running cloud workloads. To address this problem, we investigate the microarchitectural behavior of scale-out workloads and present opportunities to enable specialized processor designs that closely match the needs of the cloud.
Autors: Ferdman, Michael;Adileh, Almutaz;Kocberber, Onur;Volos, Stavros;Alisafaee, Mohammad;Jevdjic, Djordje;Kaynak, Cansu;Popescu, Adrian Daniel;Ailamaki, Anastasia;Falsafi, Babak;
Appeared in: IEEE Micro
Publication date: Jun 2014, volume: 34, issue:3, pages: 31 - 42
Publisher: IEEE
 
» A Case-Based Analysis of Active Data Warehousing
Abstract:
nullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnul- nullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnullnull
Autors: Bose, Indranil;Siu Bun, Ben Hui;
Appeared in: IT Professional
Publication date: Jun 2014, volume: 16, issue:3, pages: 52 - 60
Publisher: IEEE
 
» A CMOS Envelope-Tracking Transmitter With an On-Chip Common-Gate Voltage Modulation Linearizer
Abstract:
This letter presents a fully integrated CMOS envelope-tracking transmitter with an on-chip common-gate voltage modulation linearizer that achieves an average output power of 26/23.5 dBm with a PAE of 33/28%, an ACLR of at a frequency of 1.9 GHz for 3.84 MHz BW 3.5 dB PAPR WCDMA and 5 MHz BW 7.5 dB PAPR LTE signals in an 0.18- CMOS process. The CMOS ET transmitter is integrated with an envelope amplifier, two pairs of saturated power amplifiers, and an on-chip linearizer. The total chip size is 2.5 1.5 with the input/output on-chip transformers and matching networks.
Autors: Kim, W.-Y.;Son, H.S.;Kim, J.H.;Jang, J.Y.;Oh, I.Y.;Park, C.S.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jun 2014, volume: 24, issue:6, pages: 406 - 408
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: Jun 2014, volume: 50, issue:3, pages: 1994 - 2004
Publisher: IEEE
 
» A Cognitive Filter to Automatically Determine Scintillation Detector Materials and to Control Their Spectroscopic Resolution During Temperature Changes
Abstract:
The shape of the nuclear signal from scintillators contains information about the detection material from which it originated and its current temperature. A digital filter for this type of signals is presented that automatically extracts both of these pieces of information from the shape of the signals and controls the temperature dependency of the resolution by continuous adaption to this shape. Hereby, nuclear signals are a-priori modelled by an all-pole filter. The concept combines a deconvolution approach based on this model with a least-mean-squares iteration. Beneath the iteration, there is a continuous assessment of the signal shape where the mean-squared distance between the assumed shape and measured shape acts as control parameter for the resolution. From the information stored inside the dynamic filter parameters, the material characteristics are retrieved to identify the detector material. An implementation into a multi-channel-analyser is shown and the technique is verified under real-world environmental conditions.
Autors: Neuer, M.J.;Jacobs, E.;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Jun 2014, volume: 61, issue:3, pages: 1304 - 1310
Publisher: IEEE
 
» A compact chaotic laser device with a two-dimensional external cavity structure
Abstract:
We propose a compact chaotic laser device, which consists of a semiconductor laser and a two-dimensional (2D) external cavity for delayed optical feedback. The overall size of the device is within 230 μm × 1 mm. A long time delay sufficient for chaos generation can be achieved with the small area by the multiple reflections at the 2D cavity boundary, and the feedback strength is controlled by the injection current to the external cavity. We experimentally demonstrate that a variety of output properties, including chaotic output, can be selectively generated by controlling the injection current to the external cavity.
Autors: Sunada, Satoshi;Fukushima, Takehiro;Shinohara, Susumu;Harayama, Takahisa;Arai, Kenichi;Adachi, Masaaki;
Appeared in: Applied Physics Letters
Publication date: Jun 2014, volume: 104, issue:24, pages: 241105 - 241105-4
Publisher: IEEE
 
» A Compact Interface-Trapped-Charge-Induced Subthreshold Current Model for Surrounding-Gate MOSFETs
Abstract:
With the effects of equivalent oxide charges on the flatband voltage, we report a compact interface-trapped-charge-induced subthreshold current model for the surrounding-gate (SRG) MOSFETs based on the scaling equation and the drift–diffusion approach. It is found that a thin gate oxide can effectively reduce the subthreshold current degradation caused by the positive/negative trapped charges. In contrast to the thin gate oxide, a thick silicon film is required to alleviate the subthreshold current degradation caused by the negative trapped charges. In comparison with the fresh device, the damaged device with negative/positive trapped charges can decrease/increase more subthreshold current roll-up caused by the short-channel effects (SCEs). The model can be used to explore the hot-carrier-induced subthreshold current degradation for the SRG MOSFETs for its memory cell application.
Autors: Chiang, T.;
Appeared in: IEEE Transactions on Device and Materials Reliability
Publication date: Jun 2014, volume: 14, issue:2, pages: 766 - 768
Publisher: IEEE
 
» A Compact Low-Power 320-Gb/s WDM Transmitter Based on Silicon Microrings
Abstract:
We demonstrate a compact and low-power wavelength-division multiplexing transmitter near a 1550-nm wavelength using silicon microrings. The transmitter is implemented on a silicon-on-insulator photonics platform with a compact footprint of 0.5 . The transmitter incorporates 8 wavelength channels with 200-GHz spacing. Each channel achieved error-free operation at 40 Gb/s, resulting in an aggregated data transmission capability of 320 Gb/s. To our knowledge, this is the highest aggregated data rate demonstrated in silicon wavelength-division multiplexing transmitters. Owing to the small device capacitance and the efficient pn-junction modulator design, the transmitter achieves low energy-per-bit values of 36 fJ/bit under 2.4 drive and 144 fJ/bit under 4.8 drive. Comparisons are made to a commercial lithium niobate modulator in terms of bit-error-rate versus optical signal-to-noise ratio.
Autors: Ding, R.;Liu, Y.;Li, Q.;Xuan, Z.;Ma, Y.;Yang, Y.;Lim, A.E.-J.;Lo, G.-Q.;Bergman, K.;Baehr-Jones, T.;Hochberg, M.;
Appeared in: IEEE Photonics Journal
Publication date: Jun 2014, volume: 6, issue:3, pages: 1 - 8
Publisher: IEEE
 
» A Compact Multi-Frequency, High Power Radiating System Combining Dual-Band, Electrically Small Magnetic EZ Antennas and Multi-Frequency Standing Wave Oscillator Sources
Abstract:
High power microwave (HPM) sources are typically bulky and massive in order to be able to radiate the extremely high source powers with a good impedance match and low losses. For this reason, it is sometimes difficult to incorporate an HPM antenna onto a desired platform when the available space is small. In previous work, we have adapted an electrically small EZ antenna to operate with a mesoband, quarter-wave oscillator source. The EZ antenna operates over a ground plane, but is conformal and low profile in that the electrical size is on the order of , making it attractive for applications where there is sufficient internal space to place a full source, but only limited space outside the platform for the radiating subsystem. Here we extend the capabilities of the oscillator/EZ antenna combination by introducing a dual band design for the antenna and altering the oscillator to produce multiple resonant frequencies. Designs are shown here that operate in the UHF (500–800 MHz) and L-band (1.5–1.8 GHz), but the operation frequencies are essentially arbitrary. This paper shows modeling results that predict high antenna efficiency with electrical sizes of at .
Autors: Ramon, E.S.;Tyo, J.S.;Ziolkowski, R.W.;Skipper, M.C.;Abdalla, M.D.;Martin, J.M.;Altgilbers, L.L.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jun 2014, volume: 62, issue:6, pages: 3281 - 3289
Publisher: IEEE
 
» A compact neutron spectrometer for characterizing inertial confinement fusion implosions at OMEGA and the NIF
Abstract:
A compact spectrometer for measurements of the primary deuterium-tritium neutron spectrum has been designed and implemented on the OMEGA laser facility [T. Boehly et al., Opt. Commun. 133, 495 (1997)]. This instrument uses the recoil spectrometry technique, where neutrons produced in an implosion elastically scatter protons in a plastic foil, which are subsequently detected by a proton spectrometer. This diagnostic is currently capable of measuring the yield to ∼±10% accuracy, and mean neutron energy to ∼±50 keV precision. As these compact spectrometers can be readily placed at several locations around an implosion, effects of residual fuel bulk flows during burn can be measured. Future improvements to reduce the neutron energy uncertainty to ±15−20 keV are discussed, which will enable measurements of fuel velocities to an accuracy of ∼±25−40 km/s.
Autors: Zylstra, A.B.;Gatu Johnson, M.;Frenje, J.A.;Seguin, F.H.;Rinderknecht, H.G.;Rosenberg, M.J.;Sio, H.W.;Li, C.K.;Petrasso, R.D.;McCluskey, M.;Mastrosimone, D.;Glebov, V.Yu.;Forrest, C.;Stoeckl, C.;Sangster, T.C.;
Appeared in: Review of Scientific Instruments
Publication date: Jun 2014, volume: 85, issue:6, pages: 063502 - 063502-9
Publisher: IEEE
 
» A comparative transport study of Bi2Se3 and Bi2Se3/yttrium iron garnet
Abstract:
Bilayers of 20 quintuple layer Bi2Se3 on 30 nm thick yttrium iron garnet (YIG) have been grown with molecular beam epitaxy in conjunction with pulsed laser deposition. The presence of the ferri-magnetic insulator YIG causes additional scattering to the surface states of the Bi2Se3 topological insulator layer, as indicated by the temperature dependence of the resistivity. From the two-channel analysis of the Hall data, we find that the surface contribution in the bilayer samples is greatly reduced. Furthermore, the weak antilocalization effect from the surface states is clearly suppressed due to the presence of the YIG layer.
Autors: Jiang, Zilong;Katmis, Ferhat;Tang, Chi;Wei, Peng;Moodera, Jagadeesh S.;Shi, Jing;
Appeared in: Applied Physics Letters
Publication date: Jun 2014, volume: 104, issue:22, pages: 222409 - 222409-5
Publisher: IEEE
 
» A Comparison of Multipactor Predictions Using Two Popular Secondary Electron Models
Abstract:
Multipactor is a resonant phenomenon in which an electromagnetic field causes stray electrons to impact a surface, liberating secondary electrons, in such a way that the process can sustain itself. This phenomenon is of considerable practical interest in the design and operation of microwave windows, waveguides, and radio frequency resonant structures. The formation of multipactor is strongly dependent upon the secondary electron yield (SEY) of a surface, and the emission velocities of the emitted electrons. Two SEY models are popular within different technical communities: 1) the microwave industry frequently uses a model proposed by Vaughan and 2) the particle accelerator community frequently uses a model proposed by Furman and Pivi. This research examines the level of agreement between multipactor predictions using the two SEY models.
Autors: Rice, S.A.;VerboncoeurIEEE, J.P.;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Jun 2014, volume: 42, issue:6, pages: 1484 - 1487
Publisher: IEEE
 
» A Complementary Dual-Contact MEMS Switch Using a “Zipping” Technique
Abstract:
This paper presents a microelectromechanical systems contact switch having both hard and soft contact materials in a single cantilever-type switching device. It operates with a zipping mechanism within which both contact materials (Pt-to-Pt and Au-to-Au) make individual contact sequentially and then detach in a reverse sequence to take advantage of both contact materials: low contact resistance and high reliability in a hot switching condition. In addition, an extended gate electrode and double T-shape cantilever beam structures effectively facilitate the sequential actuation. The fabricated switch successfully demonstrated a “dual-contact concept”—it made two sequential contacts at 31 (Pt-to-Pt) and 56 V (Au-to-Au) and it was then detached at 49 (Au-to-Au) and 23 V (Pt-to-Pt) in a single switching operation. Also, it achieved a low contact resistance of 0.3–0.5 (including beam and some portion of the signal line resistances) at gate voltage from 60 to 70 V owing to the Au-to-Au contact in the device. Simultaneously, negligible contact resistance variation was observed during 2 cycles at a voltage/current level of 10 V/10 mA under hot switching and unpackaged environments, representing -fold longer lifetime than that of a conventional Au-to-Au cantilever switch fabricated on the same wafer.
Autors: Song, Y.;Kim, M.;Seo, M.;Yoon, J.;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Jun 2014, volume: 23, issue:3, pages: 710 - 718
Publisher: IEEE
 
» A Compliant MEMS Device for Out-of-Plane Displacements With Thermo-Electric Actuation
Abstract:
A MEMS actuator for micrometric displacements in the out-of-plane direction is proposed in this paper. The device is based on a compliant micromechanism composed of a thick layer of nickel and two thin layers of silicon nitride ensuring displacements in the out-of-plane direction. Its actuation is thermo-electrically performed, the polysilicon resistor encapsulated between the two thin silicon nitride layers is heated by Joule effect; the obtained thermo-mechanical deformation is therefore converted into an out of plane displacement thanks to the compliant mechanism realized in the device structure. The behavior of the device has been analytically modeled through the pseudo-rigid body model methodology and simulated with finite elements models in order to study and optimize its performance. The results coming from the presented models and the device operation have been experimentally validated by characterizing a prototype of this device micro-fabricated in the MetalMUMPs process from MEMSCAP. The maximum displacement of the device is with a maximum actuation voltage of 90 V and the maximum exerted force is .
Autors: Vitellaro, G.;L'Episcopo, G.;Trigona, C.;Ando, B.;Baglio, S.;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Jun 2014, volume: 23, issue:3, pages: 661 - 671
Publisher: IEEE
 
» A Compound Pressure Signal Acquisition System for Multichannel Wrist Pulse Signal Analysis
Abstract:
In traditional Chinese pulse diagnosis (TCPD), to analyze the health condition of a patient, a practitioner should put three fingers on the wrist of the patient to adaptively feel the fluctuations in the radial pulse at the styloid processes. Thus, for comprehensive pulse signal acquisition, we should efficiently and accurately capture pulse signals at different positions and under different pressures. However, most conventional pulse signal acquisition devices can only capture signal at one position and under a fixed pressure, and thus only capture limited pulse diagnostic information. In this paper, we propose our novel solution to the problems of sensor positioning, sensor array design, pressure adjustment, and mechanical structure design, resulting in a compound system for multichannel pulse signal acquisition. Compared with the other systems, our system provides a systematic solution to sensor positioning, is effective in measuring the width of the pulse, and can capture multichannel pulse signals together with subsignals under different hold down pressures. Experimental results show that multichannel signals can achieve higher classification performance than single-channel signals.
Autors: Wang, P.;Zuo, W.;Zhang, D.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jun 2014, volume: 63, issue:6, pages: 1556 - 1565
Publisher: IEEE
 
» A Computational Model of Narrative Generation for Surprise Arousal
Abstract:
This paper describes our effort for a planning-based computational model of narrative generation that is designed to elicit surprise in the reader's mind, making use of two temporal narrative devices: flashback and foreshadowing. In our computational model, flashback provides a backstory to explain what causes a surprising outcome, while foreshadowing gives hints about the surprise before it occurs. Here, we present Prevoyant, a planning-based computational model of surprise arousal in narrative generation, and analyze the effectiveness of Prevoyant. The work here also presents a methodology to evaluate surprise in narrative generation using a planning-based approach based on the cognitive model of surprise causes. The results of the experiments that we conducted show strong support that Prevoyant effectively generates a discourse structure for surprise arousal in narrative.
Autors: Bae, B.-C.;Young, R.M.;
Appeared in: IEEE Transactions on Computational Intelligence and AI in Games
Publication date: Jun 2014, volume: 6, issue:2, pages: 131 - 143
Publisher: IEEE
 
» A Configurable and Strong RAS Solution for Die-Stacked DRAM Caches
Abstract:
The resiliency problem of die-stacked memory will become important because of its lack of serviceability. This article details how to provide practical and cost-effective reliability, availability, and serviceability support for die-stacked DRAM cache architectures. The proposed approach can provide varying levels of protection, from fine-grained single-bit upsets to coarser-grained faults within the constraints of commodity non-error-correcting code DRAM stacks.
Autors: Sim, Jaewoong;Loh, Gabriel H.;Sridharan, Vilas;O'Connor, Mike;
Appeared in: IEEE Micro
Publication date: Jun 2014, volume: 34, issue:3, pages: 80 - 90
Publisher: IEEE
 
» A Consensus Model to Detect and Manage Noncooperative Behaviors in Large-Scale Group Decision Making
Abstract:
Consensus reaching processes in group decision making attempt to reach a mutual agreement among a group of decision makers before making a common decision. Different consensus models have been proposed by different authors in the literature to facilitate consensus reaching processes. Classical models focus on solving group decision making problems where few decision makers participate. However, nowadays, societal and technological trends that demand the management of larger scales of decision makers, such as e-democracy and social networks, add a new requirement to the solution of consensus-based group decision making problems. Dealing with such large groups implies the need for mechanisms to detect decision makers’ noncooperative behaviors in consensus, which might bias the consensus reaching process. This paper presents a consensus model suitable to manage large scales of decision makers, which incorporates a fuzzy clustering-based scheme to detect and manage individual and subgroup noncooperative behaviors. The model is complemented with a visual analysis tool of the overall consensus reaching process based on self-organizing maps, which facilitates the monitoring of the process performance across the time. The consensus model presented is aimed to the solution of consensus processes involving large groups.
Autors: Palomares, I.;Martinez, L.;Herrera, F.;
Appeared in: IEEE Transactions on Fuzzy Systems
Publication date: Jun 2014, volume: 22, issue:3, pages: 516 - 530
Publisher: IEEE
 
» A context-aware system architecture for leak point detection in the large-scale petrochemical industry
Abstract:
In the large-scale petrochemical industry, one of the most concerning problems is the leakage of toxic gas. To solve this problem, it is necessary to locate the leak points and feed the possible location of leak points back to rescuers. Although some researchers have previously presented several methods to locate leak points, they ignored the impact of external factors, such as wind, and internal factors, such as the internal pressure of equipment, on the accurate detection of leak points. Fundamentally, both of those factors belong to context-aware data in a context-aware system. Therefore, this article proposes a context-aware system architecture for leak point detection in the large-scale petrochemical industry. In this three-layer architecture, a distributed database based on data categorization is designed in the storage layer, which is able to choose the most efficient approach to store the context-aware data from the gathering layer according to different context-aware data types. Then a real-time template matching algorithm for context-aware systems is presented in the computing layer to process the context-aware data stream. The architecture is a new scheme for accurate leak point detection, which is more consistent with practical application in the large scale petrochemical industry.
Autors: Wang, K.;Lu, H.;Shu, L.;Rodrigues, J.J.P.C.;
Appeared in: IEEE Communications Magazine
Publication date: Jun 2014, volume: 52, issue:6, pages: 62 - 69
Publisher: IEEE
 
» A Cross-Modal Approach for Extracting Semantic Relationships Between Concepts Using Tagged Images
Abstract:
This paper presents a cross-modal approach for extracting semantic relationships between concepts using tagged images. In the proposed method, we first project both text and visual features of the tagged images to a latent space using canonical correlation analysis (CCA). Then, under the probabilistic interpretation of CCA, we calculate a representative distribution of the latent variables for each concept. Based on the representative distributions of the concepts, we derive two types of measures: the semantic relatedness between the concepts and the abstraction level of each concept. Because these measures are derived from a cross-modal scheme that enables the collaborative use of both text and visual features, the semantic relationships can successfully reflect semantic and visual contexts. Experiments conducted on tagged images collected from Flickr show that our measures are more coherent to human cognition than the conventional measures that use either text or visual features, or the WordNet-based measures. In particular, a new measure of semantic relatedness, which satisfies the triangle inequality, obtains the best results among different distance measures in our framework. The applicability of our measures to multimedia-related tasks such as concept clustering, image annotation and tag recommendation is also shown in the experiments.
Autors: Katsurai, M.;Ogawa, T.;Haseyama, M.;
Appeared in: IEEE Transactions on Multimedia
Publication date: Jun 2014, volume: 16, issue:4, pages: 1059 - 1074
Publisher: IEEE
 
» A Degradation Model of Double Gate and Gate-All-Around MOSFETs With Interface Trapped Charges Including Effects of Channel Mobile Charge Carriers
Abstract:
The reliability of multigate metal-oxide-semiconductor (MOS) devices is an important issue for novel nanoscale complementary MOS (CMOS) technologies. We present an analytic degradation model of double-gate (DG) and gate-all-around (GAA) MOS field-effect transistors (MOSFETs) in the presence of localized interface charge. Furthermore, we consider the effect of channel mobile charge carriers that significantly enhances the accuracy of our model. In our model, an accurate definition of threshold voltage in terms of minimum channel carrier density is used. The proposed model accurately depicts the effect of hot-carrier-induced degradation (HCD) on the surface potential, threshold voltage, and subthreshold swing. The results show a good agreement with the technology computer-aided design (TCAD) SENTAURUS device simulator over a wide range of device parameters. The modeling results show that the HCD effect become more dominant for scaled-down DG/GAA MOSFET devices. A comparative HCD degradation analysis carried for DG and GAA MOSFETs to understand their reliability limits show that GAA has greater immunity to HCD than DG MOSFET. This highlights model accuracy and provides crucial insights for HCD-tolerant multigate MOSFET design.
Autors: Shankar, R.;Kaushal, G.;Maheshwaram, S.;Dasgupta, S.;Manhas, S.K.;
Appeared in: IEEE Transactions on Device and Materials Reliability
Publication date: Jun 2014, volume: 14, issue:2, pages: 689 - 697
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: Jun 2014, volume: 11, issue:3, pages: 280 - 291
Publisher: IEEE
 
» A Derivation of the Source-Channel Error Exponent Using Nonidentical Product Distributions
Abstract:
This paper studies the random-coding exponent of joint source-channel coding for a scheme where source messages are assigned to disjoint subsets (referred to as classes), and codewords are independently generated according to a distribution that depends on the class index of the source message. For discrete memoryless systems, two optimally chosen classes and product distributions are found to be sufficient to attain the sphere-packing exponent in those cases where it is tight.
Autors: Tauste Campo, A.;Vazquez-Vilar, G.;Guillen i Fabregas, A.;Koch, T.;Martinez, A.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jun 2014, volume: 60, issue:6, pages: 3209 - 3217
Publisher: IEEE
 
» A Design for In-Situ Measurement of Optical Degradation of High Power Light-Emitting Diodes Under Accelerated Life Test
Abstract:
To better understand the reliability problem in high-power light-emitting diodes (LEDs), an online test is critical under an accelerated life test. In this paper, an experimental equipment was proposed for in situ measurement to evaluate the degradation of LED's optical properties. Signals such as illuminance and correlated color temperature were transmitted by the heat-resistant optical cable and were finally collected by detectors with high precision. The multichannel outputs were provided to simultaneously measure several samples. The measuring distance optimization was conducted by a ray tracing method, and the characteristics of optical output were listed. Accelerated life tests also indicate that the system error is less than 0.2%, and the measuring uncertainty of equipment can be controlled within 2%. A comparison experiment according to LM-80 measurement standard also shows a good agreement between the experimental data and the reference value.
Autors: Chen, Q.;Chen, Q.;Liu, S.;Luo, X.;
Appeared in: IEEE Transactions on Device and Materials Reliability
Publication date: Jun 2014, volume: 14, issue:2, pages: 645 - 650
Publisher: IEEE
 
» A Discriminative Structural Similarity Measure and its Application to Video-Volume Registration for Endoscope Three-Dimensional Motion Tracking
Abstract:
Pub DtlEndoscope 3-D motion tracking, which seeks to synchronize pre- and intra-operative images in endoscopic interventions, is usually performed as video-volume registration that optimizes the similarity between endoscopic video and pre-operative images. The tracking performance, in turn, depends significantly on whether a similarity measure can successfully characterize the difference between video sequences and volume rendering images driven by pre-operative images. The paper proposes a discriminative structural similarity measure, which uses the degradation of structural information and takes image correlation or structure, luminance, and contrast into consideration, to boost video-volume registration. By applying the proposed similarity measure to endoscope tracking, it was demonstrated to be more accurate and robust than several available similarity measures, e.g., local normalized cross correlation, normalized mutual information, modified mean square error, or normalized sum squared difference. Based on clinical data evaluation, the tracking error was reduced significantly from at least 14.6 mm to 4.5 mm. The processing time was accelerated more than 30 frames per second using graphics processing unit.
Autors: Luo, X.;Mori, K.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jun 2014, volume: 33, issue:6, pages: 1248 - 1261
Publisher: IEEE
 
» A Double Stator Through-hole Type Contactless Slipring for Rotary Wireless Power Transfer Applications
Abstract:
Contactless sliprings provide a safe and reliable power transfer solution with low maintenance for rotary applications. The magnetic design is a critical part of such a contactless slipring system (CSS).This paper presents a double stator design of a CSS for transferring power to rotatable loads and compares it against existing coaxial and face to face CSS systems. The magnetic coupling coefficient of the proposed system is improved greatly by having two stationary parts and a single rotatable coil sandwiched in between. An accurate 3-D-FEM modeling is developed to analyze the magnetic coupling characteristics of the system, and a practical prototype is constructed to evaluate its actual performance. A method of shielding the stray magnetic field using aluminium and ferrite materials has been presented. As a unique feature of the proposed structure, the magnetic coupling between the primary and secondary is constant for any angle of rotation. Moreover, the proposed system is robust and easy to assemble mechanically as the rotating part is just a single coil without any rotating ferrites. Simulation and practical results show that with the same core geometry and an extra coil, the new system is able to transfer about four times more power than a typical existing contactless slipring design.
Autors: Abdolkhani, A.;Hu, A.P.;Nair, N.-K.C.;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Jun 2014, volume: 29, issue:2, pages: 426 - 434
Publisher: IEEE
 
» A Downstream Power Back-Off Procedure for Mixed FTTC and FTTDp Scenarios
Abstract:
VDSL2 achieves high bit rates thanks to far-end crosstalk suppression and proper selection of the access network infrastructure. In this paper, we consider one architectural solution, which adopts the standard VDSL2 profile in a Fiber-To-The-Distribution point (FTTDp). During the transition process, FTTDp has to coexist with Fiber-To-The-Cabinet (FTTC) in a mixed VDSL2 scenario. Downstream Power Back-Off (DPBO) for FTTDp is effective to mitigate interference among FTTC and FTTDp. When FTTC terminals are vectored, DPBO leads to reduction of the maximum bit rate for FTTDp as compared to FTTC. In this paper, we propose a modification of the ITU DPBO procedure for FTTC and FTTDp to achieve the same bit rate. The maximum power assigned to FTTDp users is now proportional to the average received power of the vectored FTTC users at the Distribution Point. We obtain the proportionality coefficient, which depends on the number of active FTTC and FTTDp terminals and it is independent of the sub-carrier frequency.
Autors: Mazzenga, F.;Giuliano, R.;Petracca, M.;Vari, M.;Vatalaro, F.;
Appeared in: IEEE Communications Letters
Publication date: Jun 2014, volume: 18, issue:6, pages: 965 - 968
Publisher: IEEE
 
» A Dynamic Calibration Method for Pirani Gauges Embedded in Fluidic Networks
Abstract:
This paper describes in situ dynamic calibration of microfabricated Pirani gauges, which are commonly used to measure vacuum levels in microsystems that may include pumps, valves, and other pressure modulation elements. Calibration is accomplished with a configuration where two sides of the supporting membrane of a Pirani gauge are at different pressures: an interior pressure within the microsystems and an exterior ambient pressure that can be directly controlled. This particular configuration is increasingly common as Pirani gauges are embedded in complex fluidic pathways such as those found in micro-gas chromatographs and multistage gas pumps. In the dynamic calibration the ambient pressure is rapidly modulated, while the interior pressure in the sense gap of the Pirani gauge remains relatively unchanged. The exterior pressure that is equal to the interior pressure is determined by a regression model. The dynamic calibration procedure and subsequent error analysis are illustrated by application to a 162-stage monolithic Knudsen vacuum pump. For this device, dynamic calibration improves the estimated upstream pressure from 30 (as suggested by uncorrected static calibration) to 0.9 Torr, with a 95.4% confidence interval from 0.7 to 1.1 Torr, assuming normal (Gaussian) distribution. These results demonstrate that dynamic calibration can be significantly more accurate than conventional static calibration for certain types of devices.
Autors: An, S.;Gianchandani, Y.B.;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Jun 2014, volume: 23, issue:3, pages: 699 - 709
Publisher: IEEE
 
» A Dynamic Master/Slave Reactive Power-Management Scheme for Smart Grids With Distributed Generation
Abstract:
This paper introduces a novel coordinated voltage-control (CVC) scheme for distributed generations (DGs) that relies on adaptively changing the roles (master or slave) of the devices [inverter-based DG, diesel generator, and online tap changer (OLTC)] within the smart grid, depending on system conditions. In addition, the proposed scheme imposes different control response and bandwidth on the devices to coordinate the reactive power among distributed generations (DGs) and OLTC steps. The main objective of the proposed method is twofold: 1) to maximize the reactive power reserve of DGs and, hence, facilitate reaction during contingency situations and 2) to provide voltage regulation during normal operating conditions. The simulated distribution system includes inverter-based DGs (photovoltaic and wind turbine), diesel generator, and OLTC and the potential of the CVC scheme is evaluated and analyzed in view of improving voltage profile, maximizing the reactive power reserve, enhancing fault ride through and improving the transient stability margin. The control algorithm is examined under steady state, load excursion, and three-phase-to-ground fault conditions. The results demonstrate the ability of the proposed CVC scheme to satisfy the targeted objectives with significant improvement in the maximum critical clearing time. The proposed scheme is independent of real-time measurements and is widely adaptive to the dynamics of power systems, thus making it quite suitable for utility implementation.
Autors: El Moursi, M.S.;Zeineldin, H.H.;Kirtley, J.L.;Alobeidli, K.;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Jun 2014, volume: 29, issue:3, pages: 1157 - 1167
Publisher: IEEE
 
» A Dynamic Programming Algorithm for Reliable Network Design
Abstract:
This paper addresses an NP-hard problem to design a network topology with maximum all-terminal reliability subject to a cost constraint, given the locations of the various computer centers (nodes), their connecting links, each link's reliability and cost, and the maximum budget cost to install the links. Because cost is always a major focus in network design, this problem is practical for critical applications requiring maximized reliability. This paper first formulates a Dynamic Programming (DP) scheme to solve the problem. A DP approach, called DPA-1, generates the topology using all spanning trees of the network . The paper shows that DPA-1 is optimal if the spanning trees are optimally ordered. Further, the paper describes an alternative DP algorithm, called DPA-2, that uses only spanning trees ( , where ) sorted in increasing weight and lexicographic order to improve the time efficiency of DPA-1 while producing similar results. Extensive simulations using hundreds of benchmark networks that contain up to spanning trees show the merits of using the sorting method, and the effectiveness of our algorithms. DPA-2 is able to generate 85% optimal results, while using only a small number of spanning trees, and up to 16.83 CPU seconds. Furthermore, the non-optimal results are only up to 3.4% off from optimal for the simulated examples.
Autors: Elshqeirat, B.;Soh, S.;Rai, S.;Lazarescu, M.;
Appeared in: IEEE Transactions on Reliability
Publication date: Jun 2014, volume: 63, issue:2, pages: 443 - 454
Publisher: IEEE
 
» A Fade Level-Based Spatial Model for Radio Tomographic Imaging
Abstract:
RSS-based device-free localization (DFL) monitors changes in the received signal strength (RSS) measured by a network of static wireless nodes to locate and track people without requiring them to carry or wear any electronic device. Current models assume that the spatial impact area, i.e., the area in which a person affects a link's RSS, has constant size. This paper shows that the spatial impact area varies considerably for each link. Data from extensive experiments are used to derive a spatial weight model that is a function of the fade level, i.e., a measure of whether a link is experiencing destructive or constructive multipath interference, and of the sign of RSS change. In addition, a measurement model is proposed which calculates for each RSS measurement the probability of a person being located inside the derived spatial impact area. An online radio tomographic imaging (RTI) system is described which uses channel diversity and the presented models. Experiments in an open indoor environment, in a typical one-bedroom apartment and in a through-wall scenario are conducted to determine the performance of the proposed system. We demonstrate that the new system is capable of localizing and tracking a person with high accuracy ( m) in all the environments, without the need to change the model parameters.
Autors: Kaltiokallio, O.;Bocca, M.;Patwari, N.;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Jun 2014, volume: 13, issue:6, pages: 1159 - 1172
Publisher: IEEE
 
» A Fair Comparison of Pull and Push Strategies in Large Distributed Networks
Abstract:
In this paper, we compare the performance of the pull and push strategies in a large homogeneous distributed system. When a pull strategy is in use, lightly loaded nodes attempt to steal jobs from more highly loaded nodes, while under the push strategy, more highly loaded nodes look for lightly loaded nodes to process some of their jobs. Given the maximum allowed overall probe rate and arrival rate , we provide closed-form solutions for the mean response time of a job for the push and pull strategy under the infinite system model. More specifically, we show that the push strategy outperforms the pull strategy for any probe rate when , where is the golden ratio. More generally, we show that the push strategy prevails if and only if . We also show that under the infinite system model, a hybrid pull-and-push strategy is always inferior to the pure pull or push strategy. The relation between the finite and infinite system model is discussed, and simulation results that validate the infinite system model are provided.
Autors: Minnebo, W.;Van Houdt, B.;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Jun 2014, volume: 22, issue:3, pages: 996 - 1006
Publisher: IEEE
 
» A Fast Algorithm to Simulate 2-D Electromagnetic Field for Objects With Gradually Time-Varying Dielectric Permittivity
Abstract:
In some cases such as heating objects by microwave power, variation of the temperature in objects changes their dielectric permittivity and then leads to variation of the electromagnetic (EM) field. The commonly adopted method of simulation for the heating procedure is to repeatedly execute the full-wave simulation for each small time intervals, which results in a heavy computation burden. A fast algorithm for simulating 2-D sceneries is proposed for the first time. It starts with a full-wave simulation to get an initial EM field, and then corrects the EM field in an efficient way rather than repeating the full-wave simulation when the object's permittivity has slightly changed. A few sample numerical results are presented and analyzed, which verifies the accuracy, robustness, and effectiveness of the proposed fast algorithm.
Autors: Chen, X.;Chen, F.;Huang, K.;Xu, X.-B.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jun 2014, volume: 62, issue:6, pages: 1284 - 1290
Publisher: IEEE
 
» A fast minimum variance beamforming method using principal component analysis
Abstract:
Minimum variance (MV) beamforming has been studied for improving the performance of a diagnostic ultrasound imaging system. However, it is not easy for the MV beamforming to be implemented in a real-time ultrasound imaging system because of the enormous amount of computation time associated with the covariance matrix inversion. In this paper, to address this problem, we propose a new fast MV beamforming method that almost optimally approximates the MV beamforming while reducing the computational complexity greatly through dimensionality reduction using principal component analysis (PCA). The principal components are estimated offline from pre-calculated conventional MV weights. Thus, the proposed method does not directly calculate the MV weights but approximates them by a linear combination of a few selected dominant principal components. The combinational weights are calculated in almost the same way as in MV beamforming, but in the transformed domain of beamformer input signal by the PCA, where the dimension of the transformed covariance matrix is identical to the number of some selected principal component vectors. Both computer simulation and experiment were carried out to verify the effectiveness of the proposed method with echo signals from simulation as well as phantom and in vivo experiments. It is confirmed that our method can reduce the dimension of the covariance matrix down to as low as 2 ?? 2 while maintaining the good image quality of MV beamforming.
Autors: Kim, K.;Park, S.;Kim, J.;Park, S.-B.;Bae, M.;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Jun 2014, volume: 61, issue:6, pages: 930 - 945
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: Jun 2014, volume: 50, issue:3, pages: 2039 - 2049
Publisher: IEEE
 
» A Feedback Controlled MEMS Nanopositioner for On-Chip High-Speed AFM
Abstract:
We report the design of a two-degree-of-freedom microelectromechanical systems nanopositioner for on-chip atomic force microscopy (AFM). The device is fabricated using a silicon-on-insulator-based process to function as the scanning stage of a miniaturized AFM. It is a highly resonant system with its lateral resonance frequency at . The incorporated electrostatic actuators achieve a travel range of 16 in each direction. Lateral displacements of the scan table are measured using a pair of electrothermal position sensors. These sensors are used, together with a positive position feedback controller, in a feedback loop, to damp the highly resonant dynamics of the stage. The feedback controlled nanopositioner is used, successfully, to generate high-quality AFM images at scan rates as fast as 100 Hz.
Autors: Mohammadi, A.;Fowler, A.G.;Yong, Y.K.;Moheimani, S.O.R.;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Jun 2014, volume: 23, issue:3, pages: 610 - 619
Publisher: IEEE
 
» A field programmable gated array-based method for performing high-precise instantaneous burst carrier frequency measurement
Abstract:
This paper proposes an instantaneous burst carrier frequency measurement scheme combined with timestamping counting method based on field programmable gated array. With the multiplication and phase shift of counting clock, multiple parallel counters run continuously, and the times of rising edge of measured frequency fx are counted simultaneously. The frequency of fx is calculated using the least squares line fitting method of regression analysis from the count values of fx and timestamping clock. Experiment results show that the proposed approach can effectively reduce the error introduced by the quantization error of ±1, improve measurement accuracy by about 2 to 3 digits, reduce measurement uncertainty by more than 20%, and diminish the processing time to 200 ns compared to traditional methods under the same measurement conditions.
Autors: Zhang, Peng;Wang, Houjun;Li, Li;Guo, Lianping;Wang, Ping;
Appeared in: Review of Scientific Instruments
Publication date: Jun 2014, volume: 85, issue:6, pages: 065112 - 065112-6
Publisher: IEEE
 
» A Finite-Element-Based Domain Decomposition Method for Efficient Simulation of Nonlinear Electromechanical Problems
Abstract:
The dual-primal finite-element tearing and interconnecting (FETI-DP) method is combined with the Newton–Raphson method to expand the capability and improve the efficiency of 3-D finite-element analysis (FEA) of nonlinear electromechanical problems. Despite its modeling capability and high degree of accuracy, FEA has high computational complexity, especially for nonlinear analysis. The FETI-DP method is a robust domain decomposition method, which has been enhanced and applied to solve electromechanical problems involving linear materials. In this paper, the FETI-DP method is extended with the Newton–Raphson method to address problems involving nonlinearity and saturation. Using parallel computing techniques, the total computation time is reduced significantly. Linear and nonlinear regions are separated using the FETI-DP method. This further improves simulation efficiency and flexibility. Cubic splines and relaxation techniques are adopted to ensure stable and fast convergence of the Newton–Raphson method. The performance of the proposed method is compared with infolytica's MagNet, a commercial 3-D FEA solver.
Autors: Yao, W.;Jin, J.-M.;Krein, P.T.;Magill, M.P.;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Jun 2014, volume: 29, issue:2, pages: 309 - 319
Publisher: IEEE
 
» A flexible skin piloerection monitoring sensor
Abstract:
We have designed, fabricated, and tested a capacitive-type flexible micro sensor for measurement of the human skin piloerection arisen from sudden emotional and environmental change. The present skin piloerection monitoring methods are limited in objective and quantitative measurement by physical disturbance stimulation to the skin due to bulky size and heavy weight of measuring devices. The proposed flexible skin piloerection monitoring sensor is composed of 3 × 3 spiral coplanar capacitor array using conductive polymer for having high capacitive density and thin enough thickness to be attached to human skin. The performance of the skin piloerection monitoring sensor is characterized using the artificial bump, representing human skin goosebump; thus, resulting in the sensitivity of −0.00252%/μm and the nonlinearity of 25.9% for the artificial goosebump deformation in the range of 0–326 μm. We also verified successive human skin piloerection having 3.5 s duration on the subject's dorsal forearms, thus resulting in the capacitance change of −6.2 fF and −9.2 fF for the piloerection intensity of 145 μm and 194 μm, respectively. It is demonstrated experimentally that the proposed sensor is capable to measure the human skin piloerection objectively and quantitatively, thereby suggesting the quantitative evaluation method of the qualitative human emotional status for cognitive human-machine interfaces applications.
Autors: Kim, Jaemin;Seo, Dae Geon;Cho, Young-Ho;
Appeared in: Applied Physics Letters
Publication date: Jun 2014, volume: 104, issue:25, pages: 253502 - 253502-5
Publisher: IEEE
 

Publication archives by date

  2017:   January     February     March     April     May     June     July     August     September     October     November     December    

  2016:   January     February     March     April     May     June     July     August     September     October     November     December    

  2015:   January     February     March     April     May     June     July     August     September     October     November     December    

  2014:   January     February     March     April     May     June     July     August     September     October     November     December    

  2013:   January     February     March     April     May     June     July     August     September     October     November     December    

  2012:   January     February     March     April     May     June     July     August     September     October     November     December    

  2011:   January     February     March     April     May     June     July     August     September     October     November     December    

  2010:   January     February     March     April     May     June     July     August     September     October     November     December    

  2009:   January     February     March     April     May     June     July     August     September     October     November     December    

 
0-C     D-L     M-R     S-Z