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Electrical and Electronics Engineering publications abstract of: 09-2014 sorted by title, page: 0
» "Spring Forward, Fall Back" [From the Editor's Desk]
Abstract:
Autors: Wood, J.;
Appeared in: IEEE Microwave Magazine
Publication date: Sep 2014, volume: 15, issue:6, pages: 6 - 14
Publisher: IEEE
 
» (111) Orientation preferred L10 FePtB patterned by block copolymer templating
Abstract:
The (111) orientation preferred L10 FePtB has been obtained by post-deposition annealing sputtered FeB/Pt multilayers on thermally oxidized silicon substrates. Block copolymer templating was employed to pattern FeBPt film. A matrix study of etch time and etch angle showed that ion-milling at 75° for 3 min yielded the highest coercivity. Reannealing after patterning process was found to improve the crystalline structure and coercivity significantly. These results suggested (111) orientation preferred L10 FePt patterned by block copolymer templating may be promising for tilted media and bit patterned media.
Autors: Su, Hao;Schwarm, Samuel C.;Douglas, Robert L.;Montgomery, Angelique;Owen, Allen G.;Gupta, Subhadra;
Appeared in: Journal of Applied Physics
Publication date: Sep 2014, volume: 116, issue:11, pages: 113906 - 113906-4
Publisher: IEEE
 
» (Im)possibility of Deterministic Commitment Over a Discrete Memoryless Channel
Abstract:
In this paper, we study the commitment over a discrete memoryless channel W : X → Y, where both a sender and a receiver are deterministic. We call it (δh, δb)-secure if it has a hiding error δh and binding error δb. For any c ∈ (0, log |X|) and any σ ∈ (0, c), we propose a framework for a message domain of size 2n(c-σ) such that any δh > minPX:H(X)=c(I(X; Y)/H(X) - c) with an exponentially (in n) small δb can be achieved, where Y is the output of W with input X and n is the number of channel uses. We show that limc→0 minPX:H(X)=c(I(X; Y)/H(X)) = 0 if and only if a very weak condition on W holds. Note that when limc→0 minPX:H(X)=c(I(X; Y)/H(X)) = 0, we are guaranteed that our framework can commit to a message from a domain of size approximately 2nc for small c with a nearly zero hiding error δh and an exponentially small binding error δb. The price for this is a small commitment rate. We obtain some impossibility results for (δb, δh). For the space M of the commitment input, we show that when |M| = O(1), then (z, o(1))-security is impossible for any z <; 1; when |M| = ω(1), then δh <; min{α/γ, 1} and δb = 2-nα is impossible where γ = lim supn→∞(log |M|/n) and α > 0.
Autors: Shaoquan Jiang;
Appeared in: IEEE Transactions on Information Forensics and Security
Publication date: Sep 2014, volume: 9, issue:9, pages: 1406 - 1415
Publisher: IEEE
 
» 1.5-kV and 2.2-m -cm Vertical GaN Transistors on Bulk-GaN Substrates
Abstract:
In this letter, vertical GaN transistors fabricated on bulk GaN substrates are discussed. A threshold voltage of 0.5 V and saturation current >2.3 A are demonstrated. The measured devices show breakdown voltages of 1.5 kV and specific on-resistance of 2.2 m -cm , which translates to a figure-of-merit of V cm .
Autors: Nie, H.;Diduck, Q.;Alvarez, B.;Edwards, A.P.;Kayes, B.M.;Zhang, M.;Ye, G.;Prunty, T.;Bour, D.;Kizilyalli, I.C.;
Appeared in: IEEE Electron Device Letters
Publication date: Sep 2014, volume: 35, issue:9, pages: 939 - 941
Publisher: IEEE
 
» 10 GHz Bandwidth 100 Watt W-Band Folded Waveguide Pulsed TWTs
Abstract:
W-band Folded Waveguide (FWG) TWTs with moderately high-power and broad-bandwidth are a key device for many applications, such as radar and imaging systems. This letter presents the development of a 10 GHz bandwidth 100 W W-band FWG pulsed TWT. The test results show that this TWT is capable to offer over 100 W output power with 10.1 GHz bandwidth.
Autors: Cai, J.;Feng, J.;Hu, Y.;Wu, X.;Du, Y.;Liu, J.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Sep 2014, volume: 24, issue:9, pages: 620 - 621
Publisher: IEEE
 
» 2-D Analytical Model for the Threshold Voltage of a Tunneling FET With Localized Charges
Abstract:
In this paper, we have developed a 2-D analytical model for the surface potential and threshold voltage of a tunneling field-effect transistor (TFET) with localized charges in the oxide. These charges are generated in the oxide due to hot carrier effects in the channel. The models are derived by dividing the channel into damaged and undamaged regions and then solving the 2-D Poisson’s equation in these regions. The threshold voltage is then extracted by using constant current method. The proposed models are verified by using 2-D device simulations. The model can be used to study the impact of localized charges on the threshold voltage of a TFET for varying device dimensions and charge densities and can also be utilized to design TFET-based charge trapped memory devices.
Autors: Vishnoi, R.;Kumar, M.J.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2014, volume: 61, issue:9, pages: 3054 - 3059
Publisher: IEEE
 
» 2-D Localization of Radio Frequency Identification Tags From Measurements of the Weighted Integrals of the Magnetic Flux Density
Abstract:
This paper presents a novel method for the localization of a passive radio frequency identification (RFID) tag in a 2-D space. First, we show that the position of the tag can be estimated as the intersection of two orthogonal lines, which are determined by the weighted integrals of the magnetic flux density created by the tag. To measure them, we developed a square magnetic sensor composed of six coils: four rectangular coils, a set of four bow-tie-shaped coils connected in series, and a square coil. Using this sensor with side lengths of 200 mm, an RFID tag was localized in a 180 mm square domain with an average error of 5.1 mm. Using the sensor with side lengths of 400 mm, the RFID tag was also localized in a 300 mm square domain with an average error of 1.8 mm.
Autors: Chiba, A.;Nara, T.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Sep 2014, volume: 50, issue:9, pages: 1 - 8
Publisher: IEEE
 
» 2013 IEEE Scientific Visualization Contest Winner: Observing Genomics and Phenotypical Patterns in the Developing Mouse Brain
Abstract:
The 2013 IEEE Scientific Visualization Contest focused on developmental neuroscience related to the mouse brain. In developmental neuroscience, researchers examine spatiotemporal patterns of gene expression to understand how brain structures evolve and vary over an organism's life. The Allen Developing Mouse Brain Atlas project generated expression data for thousands of genes with high spatial resolution over multiple developmental stages. These data have become an invaluable resource for neuroscientists and developmental biologists exploring interesting spatial and temporal patterns of gene expression. Given the extremely large amounts of data, it's desirable to apply visualization techniques to their access, analysis, and interpretation. The proposed visual-analytics system enables clear, insightful observations of the gene expression patterns for such data, focusing on structural patterns that vary across gene expression levels over six developmental stages. Users can explore patterns through specialized data-driven representations that capture emerging structure-function associations in the developing mouse brain. The system also provides an effective characterization of certain processes in the developing brain that could lead to further analysis.
Autors: Li, Qihang;Zachmann, Gabriel;Feng, David;Huang, Kun;Machiraju, Raghu;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Sep 2014, volume: 34, issue:5, pages: 88 - 97
Publisher: IEEE
 
» 2014 Humanitarian Robotics and Automation Technology Challenge [Humanitarian Technology]
Abstract:
Autors: Madhavan, R.;Marques, L.;Prestes, E.;Dasgupta, P.;Cabrita, G.;Portugal, D.;Gouveia, B.;Jorge, V.;Maffei, R.;Franco, G.;Garcia, J.;
Appeared in: IEEE Robotics & Automation Magazine
Publication date: Sep 2014, volume: 21, issue:3, pages: 10 - 16
Publisher: IEEE
 
» 25 Years of the IEEE Robotics and Automation Society, 30 Years of ICRA [President's Message]
Abstract:
Autors: Chatila, R.;
Appeared in: IEEE Robotics & Automation Magazine
Publication date: Sep 2014, volume: 21, issue:3, pages: 8 - 8
Publisher: IEEE
 
» 2 2-Slot Element for 60-GHz Planar Array Antenna Realized on Two Doubled-Sided PCBs Using SIW Cavity and EBG-Type Soft Surface fed by Microstrip-Ridge Gap Waveguide
Abstract:
A wideband 2 2-slot element for a 60-GHz antenna array is designed by making use of two double-sided printed circuit boards (PCBs). The upper PCB contains the four radiating cavity-backed slots, where the cavity is formed in substrate-integrated waveguide (SIW) using metalized via holes. The SIW cavity is excited by a coupling slot. The excitation slot is fed by a microstrip-ridge gap waveguide formed in the air gap between the upper and lower PCBs. The lower PCB contains the microstrip line, being short-circuited to the ground plane of the lower PCB with via holes, and with additional metalized via holes alongside the microstrip line to form a stopband for parallel-plate modes in the air gap. The designed element can be used in large arrays with distribution networks realized in such microstrip-ridge gap waveguide technology. Therefore, the present paper describes a generic study in an infinite array environment, and performance is measured in terms of the active reflection coefficient S11 and the power lost in grating lobes. The study shows that the radiation characteristics of the array antenna is considerably improved by using a soft surface EBG-type SIW corrugation between each 2 2-slot element in E-plane to reduce the mutual coupling. The study is verified by measurements on a 4 4 element array surrounded by dummy elements and including a transition to rectangular waveguide WR15.
Autors: Razavi, S.A.;Kildal, P.-S.;Xiang, L.;Alfonso Alos, E.;Chen, H.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2014, volume: 62, issue:9, pages: 4564 - 4573
Publisher: IEEE
 
» 3-D Flexible Nano-Textured High-Density Microelectrode Arrays for High-Performance Neuro-Monitoring and Neuro-Stimulation
Abstract:
We introduce a new 3-D flexible microelectrode array for high performance electrographic neural signal recording and stimulation. The microelectrode architecture maximizes the number of channels on each shank and minimizes its footprint. The electrode was implemented on flexible polyimide substrate using microfabrication and thin-film processing. The electrode has a planar layout and comprises multiple shanks. Each shank is three mm in length and carries six gold pads representing the neuro-interfacing channels. The channels are used in recording important precursors with potential clinical relevance and consequent electrical stimulation to perturb the clinical condition. The polyimide structure satisfied the mechanical characteristics required for the proper electrode implantation and operation. Pad postprocessing technique was developed to improve the electrode electrical performance. The planar electrodes were used for creating 3-D “Waterloo Array” microelectrode with controlled gaps using custom designed stackers. Electrode characterization and benchmarking against commercial equivalents demonstrated the superiority of the Flex electrodes. The Flex and commercial electrodes were associated with low-power implantable responsive neuro-stimulation system. The electrodes performance in recording and stimulation application was quantified through in vitro and in vivo acute and chronic experiments on human brain slices and freely-moving rodents. The Flex electrodes exhibited remarkable drop in the electric impedance (100 times at 100 Hz), improved electrode–electrolyte interface noise (dropped by four times) and higher signal-to-noise ratio (3.3 times).
Autors: Gabran, S.R.I.;Salam, M.T.;Dian, J.;El-Hayek, Y.;Perez Velazquez, J.L.;Genov, R.;Carlen, P.L.;Salama, M.M.A.;Mansour, R.R.;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Sep 2014, volume: 22, issue:5, pages: 1072 - 1082
Publisher: IEEE
 
» 40 nm Bit-Interleaving 12T Subthreshold SRAM With Data-Aware Write-Assist
Abstract:
This paper presents a new bit-interleaving 12T subthreshold SRAM cell with Data-Aware Power-Cutoff (DAPC) Write-assist to improve the Write-ability to mitigate increased device variations at low supply voltage under deep sub-100 nm processes. The disturb-free feature facilitates the bit-interleaving architecture that can reduce multiple-bit errors in a single word and enhance soft error immunity by employing error checking and correction (ECC) techniques. The proposed 12T SRAM cell is demonstrated by a 4 kb SRAM macro implemented in 40 nm general purpose (40GP) CMOS technology. The test chip operates from typical to 350 mV ( 100 mV lower than the threshold voltage) with limited by Read operation. Data can be written successfully for down to 300 mV. The measured maximum operation frequency is 11.5 MHz with total power consumption of 22 at 350 mV, 25 .
Autors: Chiu, Y.-W.;Hu, Y.-H.;Tu, M.-H.;Zhao, J.-K.;Chu, Y.-H.;Jou, S.-J.;Chuang, C.-T.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Sep 2014, volume: 61, issue:9, pages: 2578 - 2585
Publisher: IEEE
 
» 5 Gbit/s 2-tap low-swing voltage-mode transmitter with least segmented voltage-mode equalisation
Abstract:
A 2-tap low-swing voltage-mode transmitter which compensates the loss of channel at high frequency is proposed. The output driver of the proposed 2-tap transmitter consists of only two voltage-mode drivers, and thereby the design complexity of the pre-driver is greatly reduced compared with that of conventional 2N-segmented voltage-mode drivers, where N is the number of equalisation control bits. The output impedance of each voltage-mode driver is adjusted not only to make the overall output impedance matched with the characteristic impedance of the channel, but also to achieve the desired equalisation coefficient by adopting the proposed calibration circuitry. With a high equalisation coefficient, the proposed output driver consumes less power compared with the hybrid voltage-mode driver with current-mode equalisation. The proposed transmitter is implemented using a 90 nm low-power CMOS process technology and achieves 0.79 pJ/bit without equalisation and 0.98 pJ/bit with 6 dB equalisation, at the data rate of 5 Gbit/s.
Autors: Kang-Sub Kwak;Seong-Kwan Hong;Oh-Kyong Kwon;
Appeared in: Electronics Letters
Publication date: Sep 2014, volume: 50, issue:19, pages: 1371 - 1373
Publisher: IEEE
 
» 5G Mobile: Spectrum Broadening to Higher-Frequency Bands to Support High Data Rates
Abstract:
Next-generation [fifth-generation (5G)] mobile systems are broadening their spectrum to higher-frequency bands (above 6 GHz) to support a high data rate up to multigigabits per second. In this article, we have two main contributions to higher-frequency communications. First, we summarize the candidate frequency bands that are promising for 5G research, including licensed and unlicensed frequency bands. Second, a new network architecture for higher-frequency communications is proposed, which is featured with load-centric backhauling (LCB), multiple-frequency transmission, and intelligent control techniques.
Autors: Wang, Y.;Li, J.;Huang, L.;Jing, Y.;Georgakopoulos, A.;Demestichas, P.;
Appeared in: IEEE Vehicular Technology Magazine
Publication date: Sep 2014, volume: 9, issue:3, pages: 39 - 46
Publisher: IEEE
 
» 6-D Magnetic Localization and Orientation Method for an Annular Magnet Based on a Closed-Form Analytical Model
Abstract:
Magnetic tracking technology is emerging to provide an occlusion-free tracking scheme for the estimation of full pose (position and orientation) of various instruments. This brings substantial benefits for intracorporeal applications, such as for tracking of flexible or wireless endoscopic devices, and thus is significant for further computer-assisted diagnosis, interventions, and surgeries. Toward efficient magnetic tracking, a 6-D magnetic localization and orientation method is proposed in this paper. An annular permanent magnet is mounted on the exterior surface of a capsule. With a magnetic sensor array, the magnetic field can be measured and the capsule’s 3-D location and 3-D orientation information can be estimated based on proposed closed-form analytical model of annular magnet and particle swarm optimization algorithm. Magnetic dipole model and Levenberg–Marquardt algorithm are used to improve the speed and accuracy of estimation. Extensive simulation experiments show that the localization and orientation method works well with good position and orientation accuracy.
Autors: Song, S.;Li, B.;Qiao, W.;Hu, C.;Ren, H.;Yu, H.;Zhang, Q.;Meng, M.Q.;Xu, G.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Sep 2014, volume: 50, issue:9, pages: 1 - 11
Publisher: IEEE
 
» 60-GHz Thin Broadband High-Gain LTCC Metamaterial-Mushroom Antenna Array
Abstract:
A low-profile broadband metamaterial-mushroom antenna array is proposed for high-gain 60-GHz band applications. The antenna array consists of a single-layer mushroom radiating structure and a simplified single-layer substrate integrated waveguide (SIW) feeding network. A new transmission-line based model is presented to estimate the resonant frequencies of the operating and antiphase modes. With the metamaterial-mushroom structure, the closely-placed antenna elements realize less mutual couplings, higher aperture illumination efficiency compared to conventional patch antennas. An 8 8 mushroom antenna array is designed and prototyped using low-temperature cofired ceramic (LTCC), the measurement shows the antenna array with the feeding transition proposed an impedance bandwidth of 56.3–65.7 GHz with a boresight gain greater than 21.2 dBi and up to 24.2 dBi at 62.3 GHz. The proposed antenna array features the merits of high gain, broadband, compact size, and low cross-polarization levels.
Autors: Liu, W.;Chen, Z.N.;Qing, X.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2014, volume: 62, issue:9, pages: 4592 - 4601
Publisher: IEEE
 
» 64 x 48 TOF sensor in 0.35 spl mu/m CMOS with high ambient light immunity
Abstract:
A multi-pixel 64 x 48 time-of-flight (TOF) range sensor whose speciality is high immunity against ambient light is presented. The chip was fabricated in a 0.35 μm 1P4M CMOS process, whereby a single pixel occupies an area of 45 x 60 μm2 achieving a fill factor of 50%. The measured distance shows a 1σ deviation below 3.7 mm in the optimum operating range for the sensor. The measurement results show that the sensor successfully acquires the distance even when some parts of the scenery are illuminated with 180 klx ambient light. Furthermore, the most accurate method to characterise particular pixels in a multi-pixel array is for the first time used in a multi-pixel TOF sensor.
Autors: Davidovic, M.;Seiter, J.;Hofbauer, M.;Gaberl, W.;Schidl, S.;Zimmermann, H.;
Appeared in: Electronics Letters
Publication date: Sep 2014, volume: 50, issue:19, pages: 1375 - 1377
Publisher: IEEE
 
» 7T Transmit/Receive Arrays Using ICE Decoupling for Human Head MR Imaging
Abstract:
In designing large-sized volume type phased array coils for human head imaging at ultrahigh fields, e.g., 7T, minimizing electromagnetic coupling among array elements is technically challenging. A new decoupling method based on induced current compensation or elimination (ICE) for a microstrip line planar array has recently been proposed. In this study, an eight-channel transmit/receive volume array with ICE-decoupled loop elements was built and investigated to demonstrate its feasibility and robustness for human head imaging at 7T. Isolation between adjacent loop elements was better than - 25 dB with a human head load. The worst-case of the isolation between all of the elements was about - 17.5 dB. All of the MRI experiments were performed on a 7T whole-body human MR scanner. Images of the phantom and human head were acquired and -factor maps were measured and calculated to evaluate the performance of the coil array. Compared with the conventional capacitively decoupled array, the ICE-decoupled array demonstrated improved parallel imaging ability and had a higher SNR. The experimental results indicate that the transceiver array design with ICE decoupling technique might be a promising solution to designing high performance transmit/receive coil arrays for human head imaging at ultrahigh fields.
Autors: Yan, X.;Zhang, X.;Feng, B.;Ma, C.;Wei, L.;Xue, R.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Sep 2014, volume: 33, issue:9, pages: 1781 - 1787
Publisher: IEEE
 
» -Stability of Haptic Systems with Projection-Based Force Reflection
Abstract:
The problem of stability of haptic interaction with virtual objects is addressed, where the force reflection is implemented using the projection-based principle. A stability condition is derived that generalizes some previously known results to the case of projection-based force reflection. It demonstrates that, in this case, an additional design parameter is brought in that allows to increase the admissible stiffness of the virtual wall and decrease the update rate without changing the damping of the haptic device. A passivity based interpretation of the result is given in terms of interconnection of generalized passive systems where the excess of passivity of haptic device compensates the shortage of passivity of the virtual wall. In particular, it is shown that the projection-based force reflection allows to arbitrarily increase the excess of passivity of the haptic device without changing its physical damping.
Autors: Polushin, I.G.;Hasan, M.Z.;
Appeared in: IEEE Transactions on Haptics
Publication date: Sep 2014, volume: 7, issue:3, pages: 405 - 410
Publisher: IEEE
 
» -Friendly Points: A Table-Based Method to Evaluate Trigonometric Function
Abstract:
Linear (order-1) function evaluation schemes, such as bipartite and multipartite tables, are usually effective for low-precision approximations. For high-output precision, the lookup table size is often too large for practical use. This brief investigates the so-called scheme that reduces the range of an input argument to a very small interval so that trigonometric functions can be approximated with very small lookup tables and a few additions/subtractions. An optimized hardware architecture is presented and implemented in both a field-programmable gate array device and standard-cell-based technology. Experimental results show that the proposed scheme achieves more than a 50% reduction in total chip area compared with the best linear approach for a 24-bit evaluation.
Autors: Wang, D.;Muller, J.;Brisebarre, N.;Ercegovac, M.D.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Sep 2014, volume: 61, issue:9, pages: 711 - 715
Publisher: IEEE
 
» Domain Rate Control Algorithm for High Efficiency Video Coding
Abstract:
Rate control is a useful tool for video coding, especially in real-time communication applications. Most of existing rate control algorithms are based on the R - Q model, which characterizes the relationship between bitrate R and quantization Q, under the assumption that Q is the critical factor on rate control. However, with the video coding schemes becoming more and more flexible, it is very difficult to accurately model the R - Q relationship. In fact, we find that there exists a more robust correspondence between R and the Lagrange multiplier λ. Therefore, in this paper, we propose a novel λ-domain rate control algorithm based on the R - λ model, and implement it in the newest video coding standard high efficiency video coding (HEVC). Experimental results show that the proposed λ-domain rate control can achieve the target bitrates more accurately than the original rate control algorithm in the HEVC reference software as well as obtain significant R-D performance gain. Thanks to the high accurate rate control algorithm, hierarchical bit allocation can be enabled in the implemented video coding scheme, which can bring additional R-D performance gain. Experimental results demonstrate that the proposed λ-domain rate control algorithm is effective for HEVC, which outperforms the R - Q model based rate control in HM-8.0 (HEVC reference software) by 0.55 dB on average and up to 1.81 dB for low delay coding structure, and 1.08 dB on average and up to 3.77 dB for random access coding structure. The proposed λ-domain rate control algorithm has already been adopted by Joint Collaborative Team on Video Coding and integrated into the HEVC reference software.
Autors: Bin Li;Houqiang Li;Li Li;Jinlei Zhang;
Appeared in: IEEE Transactions on Image Processing
Publication date: Sep 2014, volume: 23, issue:9, pages: 3841 - 3854
Publisher: IEEE
 
» Adaptive Speed Control of a Small Wind Energy Conversion System for Maximum Power Point Tracking
Abstract:
This paper presents the design of an adaptive controller for maximum power point tracking (MPPT) of a small variable speed wind energy conversion system (WECS). The proposed controller generates the optimal torque command for the vector-controlled generator-side converter based on the wind speed estimation. The proposed MPPT control algorithm has a generic structure and can be used for different generator types. In order to verify the efficacy of the proposed adaptive controller for the MPPT of the WECS, a full converter wind turbine with a squirrel cage induction generator is used to carry out case studies using MATLAB/Simulink. The case study results show that the designed adaptive controller has good tracking performance even with unmodeled dynamics and in the presence of parameter uncertainties and unknown disturbances.
Autors: Zhao, H.;Wu, Q.;Rasmussen, C.N.;Blanke, M.;
Appeared in: IEEE Transactions on Energy Conversion
Publication date: Sep 2014, volume: 29, issue:3, pages: 576 - 584
Publisher: IEEE
 
» In Situ Interconnect Failure Prediction Using Canaries
Abstract:
A physics-of-failure-based canary approach for early identification of solder interconnect failures has been developed. The canary is composed of a resistance path formed by a near-zero ohm ceramic chip resistor soldered to pads designed to produce failure earlier than standard pad resistors, which are the target structures. The time to failure of the canary can be adjusted by adjusting the printed wiring board pad dimensions and, hence, the solder interconnect area. The developed canary approach is demonstrated through temperature cycling of the resistors. The pad width of a standard resistor is reduced by 80%, thereby reducing the interconnect life. The results from the temperature cycling experiment prove that the developed canary approach provides advanced warning of failures of the standard pad resistors. The FEA results suggest that there is a 78% increase in the strain range in the canary resistor, as compared with the standard resistor. The Engelmaier model, a physics-of-failure-based model for solder interconnect life estimation under thermal cycling, is modified to take the solder interconnect area into account. The model provides time to failure estimates for the canary and target structures. A comparison of the results from the Engelmaier model and temperature cycling experiment shows that the model provides a good estimate of time to failure of standard resistors and a conservative estimate of time to failure of the canary resistors.
Autors: Chauhan, P.;Mathew, S.;Osterman, M.;Pecht, M.;
Appeared in: IEEE Transactions on Device and Materials Reliability
Publication date: Sep 2014, volume: 14, issue:3, pages: 826 - 832
Publisher: IEEE
 
» xor-Based Encoding With Instantaneous Decoding for the Broadcast Erasure Channel With Feedback: The Three-User Case
Abstract:
We study the case of a three-user broadcast erasure channel with multiple unicast traffic sessions, where feedback from the users is fed back to the transmitter in the form of positive acknowledgment (ACK)/negative acknowledgment (NACK) messages. The capacity region of this system has been recently derived and two capacity-achieving coding algorithms employing intersession linear network coding have been proposed. Since these algorithms suffer from large computational complexity and decoding delay, our aim, in this paper, is to design a coding algorithm with reduced computational complexity and a low decoding delay that achieves a comparable rate region to the former algorithms. We exclusively consider algorithms that require no knowledge of channel statistics, only perform xor operations among the packets, and allow for instantaneous decoding by any receiver that successfully receives a packet. We present such an algorithm, named , which operates on a specially constructed network of virtual queues and, through intelligent packet combining, achieves the capacity under a general condition, which is satisfied in the following settings: 1) spatially independent identically distributed erasure channels with arbitrary values of erasure probability, and 2) spatially independent erasure channels where the maximum erasure probability does not exceed 8/9.
Autors: Athanasiadou, S.;Gatzianas, M.;Georgiadis, L.;Tassiulas, L.;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Sep 2014, volume: 13, issue:9, pages: 5274 - 5287
Publisher: IEEE
 
» A 1.7–2.2 GHz Compact Low Phase-Noise VCO Using a Widely-Tuned SIW Resonator
Abstract:
A 1.7–2.2 GHz low phase-noise voltage controlled oscillator (VCO) based on a widely-tuned substrate integrated waveguide (SIW) cavity resonator is presented. The frequency of the SIW resonator is tuned based on loading the cavity with three via posts and thus changing the field distribution inside the cavity. The widely-tunable SIW resonator is employed inside a reflective-type VCO structure resulting in a tuning range of 1.7–2.2 GHz ( 26%) and a phase noise better than dBc/Hz at a 100 kHz offset over the entire tuning range.
Autors: Pourghorban Saghati, A.;Entesari, K.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Sep 2014, volume: 24, issue:9, pages: 622 - 624
Publisher: IEEE
 
» A 10 Gb/s, 6 V p-p , Digitally Controlled, Differential Distributed Amplifier MZM Driver
Abstract:
A 10 Gb/s, digitally controlled, differential distributed amplifier (DA) optical modulator driver is implemented in 0.18 µm SiGe-BiCMOS technology. The 2.87 mm 2 prototype integrates clock phase shifters, digital latches, limiting amplifiers, broadband n+/n-well back termination resistors and a substrate-shielded output line on chip. It produces 6 V p-p differential output swing across 50 Ω loads. The output edge speed is trimmable, with 20–80% rise/fall times ranging from < 15 ps to 50 ps at 10 Gb/s. Minimum sensitivity of the ECL-compatible inputs is 65 mV p-p at 10 Gb/s single-ended, with negligible additive jitter. Measured output return loss is better than 10 dB below 35 GHz, sufficient to drive an external push-pull Mach-Zehnder optical modulator. Total power consumption is 2.13 W operating from –5.2 V and 5 V supplies. The fully-digital input interface supports scalability in the number of DA stages, output swing and to multiple output channels.
Autors: Zhao, Y.;Vera, L.;Long, J.R.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2014, volume: 49, issue:9, pages: 2030 - 2043
Publisher: IEEE
 
» A 10-Gb/s Silicon Microring Resonator-Based BPSK Link
Abstract:
We design and demonstrate for the first time an end-to-end binary phase-shift keying (BPSK) link based on silicon microring resonators, with an operational bit-rate at 10 Gb/s. The obtained bit-error-rate is below the forward error correction limit, validating the practical application of the demonstrated technique. Performance comparisons to conventional BPSK modulation and demodulation techniques are also made. The microring-based BPSK link promises a compact, energy efficient, and low-cost interconnect solution for high-capacity transceivers.
Autors: Li, Q.;Liu, Y.;Padmaraju, K.;Ding, R.;Logan, D.F.;Ackert, J.J.;Knights, A.P.;Baehr-Jones, T.;Hochberg, M.;Bergman, K.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Sep 2014, volume: 26, issue:18, pages: 1805 - 1808
Publisher: IEEE
 
» A 1000 fps Vision Chip Based on a Dynamically Reconfigurable Hybrid Architecture Comprising a PE Array Processor and Self-Organizing Map Neural Network
Abstract:
This paper proposes a vision chip hybrid architecture with dynamically reconfigurable processing element (PE) array processor and self-organizing map (SOM) neural network. It integrates a high speed CMOS image sensor, three von Neumann-type processors, and a non-von Neumann-type bio-inspired SOM neural network. The processors consist of a pixel-parallel PE array processor with parallelism, a row-parallel row-processor (RP) array processor with parallelism and a thread-parallel dual-core microprocessor unit (MPU) with parallelism. They execute low-, mid- and high-level image processing, respectively. The SOM network speeds up high-level processing in pattern recognition tasks by , which improves the chip performance remarkably. The SOM network can be dynamically reconfigured from the PE array to largely save chip area. A prototype chip with a 256 256 image sensor, a reconfigurable 64 64 PE array processor/16 16 SOM network, a 64 1 RP array processor and a dual-core 32-bit MPU was implemented in a 0.18 m CMOS image sensor process. The chip can perform image capture and various-level image processing at a high speed and in flexible fashion. Various complicated applications including M-S functional solution, horizon estimation, hand gesture recognition, face recognition are demonstrated - t high speed from several hundreds to 1000 fps.
Autors: Shi, C.;Yang, J.;Han, Y.;Cao, Z.;Qin, Q.;Liu, L.;Wu, N.-J.;Wang, Z.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2014, volume: 49, issue:9, pages: 2067 - 2082
Publisher: IEEE
 
» A 12 Bit 1.6 GS/s BiCMOS 2×2 Hierarchical Time-Interleaved Pipeline ADC
Abstract:
This paper describes a 12 bit 1.6 GS/s pipeline ADC realized in a 0.18 µm complementary BiCMOS SiGe process. The ADC consists of a four-way time-interleaved hierarchical structure and a master-slave T&H to improve the dynamic performance of the individual sub-ADCs and to reduce both the converter error rate and the complexity of the required interleaving background calibration algorithms. It achieves an SFDR of 79 dBc and 66 dBc at low and high frequency inputs, respectively and an error rate of less than 10 , and has a power consumption of 1.15 W for the core ADC.
Autors: El-Chammas, M.;Li, X.;Kimura, S.;Maclean, K.;Hu, J.;Weaver, M.;Gindlesperger, M.;Kaylor, S.;Payne, R.;Sestok, C.K.;Bright, W.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2014, volume: 49, issue:9, pages: 1876 - 1885
Publisher: IEEE
 
» A 128 96 Pixel CMOS Microdisplay Utilizing Hot Carrier Electroluminescence From Junctions in Reach Through
Abstract:
Visible light from silicon junctions under avalanche breakdown can be used to create microdisplay systems with integrated light sources. Junctions available in standard CMOS usually breaks down at much larger voltages than the typical operating voltage for integrated circuitry. It is possible to reduce the operating voltage of by making use of techniques which changes the electric field profile in light sources based on hot carrier electroluminescence such as electric field reach through between two highly doped implant regions. This work successfully demonstrates the possibility of tailoring the operating voltage and quantifying the optical performance in an integrated microdisplay consisting of a 128 by 96 pixel array based on light sources in standard CMOS. Based on the approach followed it becomes possible to integrate light sources in such a manner that it can coexist and interact with other on-chip analog and digital circuitry. The requirements for architectural features of a microdisplay in standard CMOS is discussed and it is shown to be possible to create large scale integrated circuits containing integrated light sources in standard CMOS without the need for postprocessing or additional back end modifications.
Autors: Venter, P.J.;du Plessis, M.;
Appeared in: Journal of Display Technology
Publication date: Sep 2014, volume: 10, issue:9, pages: 721 - 728
Publisher: IEEE
 
» A 13.5-mW 10-Gb/s 4-PAM Serial Link Transmitter in 0.13- CMOS Technology
Abstract:
A 13.5-mW 10-Gb/s four-level pulse-amplitude modulation (4-PAM) serial link transmitter is presented. To improve the power efficiency, a voltage-mode 4-PAM driver is proposed. It consists of voltage-scaled pull-up and pull-down networks, instead of conventional current switching networks. Not employing a tail current source, the proposed 4-PAM driver achieves the higher output voltage swing and lower power dissipation than conventional 4-PAM drivers. As a result, the proposed 4-PAM transmitter implemented in a 0.13- CMOS process achieved 10-Gb/s data rate with only 13.5-mW power dissipation.
Autors: Song, B.;Kim, K.;Lee, J.;Chung, J.;Choi, Y.;Burm, J.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Sep 2014, volume: 61, issue:9, pages: 646 - 650
Publisher: IEEE
 
» A 2 GS/s Frequency-Folded ADC-Based Broadband Sampling Receiver
Abstract:
Pub DtlA frequency-folded ADC-based broadband sampling receiver that merges sampling within the structure of a broadband downconverter is presented. The receiver channelizes a broadband input into sub-bands after digitization, while employing digital-domain harmonic and image rejection. The design offers a frequency-domain approach to simultaneously achieving high sample rate and dynamic range per-unit power consumption. Noise and distortion performance of the architecture is described. An analysis of SNR improvement during signal reconstruction that results from the use of multiple paths at baseband is presented. A 2 GS/s receiver based on this approach is implemented in a 65 nm CMOS process. The receiver spans a bandwidth from 125 MHz to 1000 MHz, and achieves a mean SNDR of 49 dB across the input bandwidth, while providing 38–43.3 dB of gain and a NF of 8.5–13.4 dB. Equalization-based calibration results in harmonic and image rejection greater than 59 dB and 58 dB, respectively, across the input bandwidth, while even better performance may be achieved for tonal interferers. The receiver consumes 104 mW from a dual 1.2/2.5 V supply.
Autors: Forbes, T.;Gharpurey, R.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2014, volume: 49, issue:9, pages: 1971 - 1983
Publisher: IEEE
 
» A 2.5-GHz Receiver Front-End With -Boosted Post-LNA -Path Filtering in 40-nm CMOS
Abstract:
This paper presents the analysis, design, and measurements of a 2.5-GHz receiver front-end in a 40-nm CMOS technology. The front-end utilizes RLC-resonator quality factor boosting and four-phase -path filtering to improve the blocker filtering capabilities of the low-noise amplifier (LNA). Systematic analysis is performed in order to obtain a thorough design approach. Particular attention is paid to the passive mixer switches in the RLC case, for which we show that minimum switch resistance does not provide best noise figure (NF), nor best relative blocker attenuation. Moreover, the -path filter extends the stable operating region of a -boosted LNA, and adding a noisy -boosting circuit can actually improve the receiver NF in practical realizations. The experimental CMOS front-end is flip-chip packaged, and a parasitic-aware input matching method for the electrostatic-discharge-protected LNA is proposed, analyzed, and verified. In nominal operation, the programmable front-end achieves a measured gain of 39 dB, an NF of 3.5 dB, and an out-of-band input-referred third order intercept point of , while consuming 48 mA from a 1.1-V supply.
Autors: Ostman, K.B.;Englund, M.;Viitala, O.;Kaltiokallio, M.;Stadius, K.;Koli, K.;Ryynanen, J.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Sep 2014, volume: 62, issue:9, pages: 2071 - 2083
Publisher: IEEE
 
» A 3–10 GHz IR-UWB CMOS Pulse Generator With 6 mW Peak Power Dissipation Using A Slow-Charge Fast-Discharge Technique
Abstract:
This letter proposes a UWB pulse generator topology featuring low peak power dissipation for applications with stringent instantaneous power requirements. This is accomplished by employing a new slow-charge fast-discharge approach to extend the time duration of the generator's peak current so that the peak value of the current is significantly reduced, while maintaining the waveform of the generated UWB pulse signal. A prototype pulse generator has been implemented using the UMC CMOS process for validation. The pulse generator offers a 3–10 GHz bandwidth, a maximum pulse repetitive rate of 1 Gpps, a minimum peak power consumption of 6 mW, and a low energy consumption of 5 pJ/pulse. The fabricated pulse generator measures .
Autors: Shen, M.;Yin, Y.-Z.;Jiang, H.;Tian, T.;Mikkelsen, J.H.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Sep 2014, volume: 24, issue:9, pages: 634 - 636
Publisher: IEEE
 
» A 3-Gb/s/ch Simultaneous Bidirectional Capacitive Coupling Transceiver for 3DICs
Abstract:
This brief presents a simultaneous bidirectional capacitive coupling transceiver for intertier communication in 3-D integrated circuits. A novel capacitive coupling interconnect structure is proposed. Optimization of the proposed interconnect structure for minimizing parasitic capacitance achieves the voltage swing of 200 mV at the voltage sensing nodes. The data rate of 3 Gb/s/ch is demonstrated in the emulated-3D interconnect. The proposed transceiver consumes 140 at 3 Gb/s/ch. The test chip was fabricated in a 65-nm CMOS technology.
Autors: Aung, M.T.L.;Lim, E.;Yoshikawa, T.;Kim, T.T.;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Sep 2014, volume: 61, issue:9, pages: 706 - 710
Publisher: IEEE
 
» A 5.4 Soft-Decision BCH Decoder for Wireless Body Area Networks
Abstract:
This paper presents an IEEE 802.15.6 compliant soft-decision BCH decoder for energy-constrained wireless body area networks. The proposed soft-decision decoder (SDD) provides a 1 dB coding gain compared to the hard-decision decoder (HDD). The improvement in BER performance can translate into power savings at the transmitter. The energy dissipation and area of the soft-decision BCH decoder is minimized by jointly considering the algorithm, architecture, and circuit parameters. An early termination strategy is proposed to reduce the number of redundant test patterns. Probabilistic sorting is proposed to determine the test patterns, and its hardware complexity is only 54.7% of the conventional sorting method. The HDD kernel is implemented by adopting the Peterson rule, reducing the area by 44.2%. A pass-transistor logic based Chien search circuit consumes 33.3% less energy compared to the standard-cell based implementation. The chip is designed to operate at the minimum energy point of 0.29 V, yielding an energy reduction of 94% compared to a direct-mapped SDD at . Fabricated in 90 nm CMOS, the chip dissipates 5.4 at 500 kHz, achieving a throughput of 6.38 Mbps.
Autors: Yang, C.-H.;Huang, T.-Y.;Li, M.-R.;Ueng, Y.-L.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Sep 2014, volume: 61, issue:9, pages: 2721 - 2729
Publisher: IEEE
 
» A 50-100-GHz Highly Integrated Octave-Bandwidth Transmitter and Receiver Chipset in SiGe Technology
Abstract:
This work presents a highly integrated transmitter (TX) and receiver (RX) chipset operating from 50 to 100 GHz. The local oscillator (LO) is realized using a high output power millimeter-wave integrated frequency synthesizer with an octave output frequency range. The proposed low-complexity discrete tuned synthesizer architecture employs a single wide-tuning range voltage-controlled oscillator core and a single-sideband mixer, which can be switched to operate as a LO amplifier. An ultra broadband variable gain amplifier, with a gain control range , is used at the output of the synthesizer to provide a tunable output power. A maximum output power from to and an output phase noise from to at 1-MHz offset are measured over the complete output frequency range. Moreover, a spurious suppression is achieved over the entire synthesizer's tuning range. The RX shows a conversion gain and a noise figure from 50 to 100 GHz. The TX's measured saturated output power is from to over the entire frequency range. The complete chipset is realized in a commercial low-cost SiGe:C technology with an $f- {t}/f_{max}$ of . Each of the TX and RX chips including the frequency synthesizers draw a current of 370 mA from a 3.3-V supply.
Autors: Nasr, I.;Knapp, H.;Aufinger, K.;Weigel, R.;Kissinger, D.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Sep 2014, volume: 62, issue:9, pages: 2118 - 2131
Publisher: IEEE
 
» A 800 kV compact peaking capacitor for nanosecond generator
Abstract:
An extremely compact high voltage peaking capacitor is developed. The capacitor has a pancake structure with a diameter of 315 mm, a thickness of 59 mm, and a mass of 6.1 kg. The novel structural design endows the capacitor with a better mechanical stability and reliability under hundreds of kilovolts pulse voltage and an inner gas pressure of more than 1.5 MPa. The theoretical value of the capacitor self-inductance is near to 17 nH. Proved by series of electrical experiments, the capacitor can endure a high-voltage pulse with a rise time of about 20 ns, a half-width duration of around 25 ns, and an amplitude of up to 800 kV in a single shot model. When the capacitor was used in an electromagnetic pulse simulator as a peaking capacitor, the rise time of the voltage pulse can be reduced from 20 ns to less than 3 ns. The practical value of the capacitor's inductance deduced from the experimental date is no more than 25 nH.
Autors: Jia, Wei;Chen, Zhiqiang;Tang, Junping;Chen, Weiqing;Guo, Fan;Sun, Fengrong;Li, Junna;Qiu, Aici;
Appeared in: Review of Scientific Instruments
Publication date: Sep 2014, volume: 85, issue:9, pages: 094706 - 094706-4
Publisher: IEEE
 
» A 94-GHz Extremely Thin Metasurface-Based BiCMOS On-Chip Antenna
Abstract:
Pub DtlA novel fully on-chip antenna based on a metasurface fabricated in a 180-nm BiCMOS process is presented. Inspired by the concept of high impedance surface (HIS), this metasurface is not used as a reflector below an antenna as commonly done. Instead, it is used as a radiator by itself. The extremely thin metasurface is composed of a patterned top two metal layers and the ground plane placed in the lowest metal layer in the process. The ground plane on the lowest metal layer of the process provides a solid shielding from the substrate and other possible circuitries. The fundamental of the antenna radiation and design are described. The measured antenna shows peak broadside gain with 8-GHz 3-dB gain bandwidth and an impedance bandwidth larger than 10 GHz. In its class of broadside radiating fully on-chip antennas, with a ground plane on the lower metal layer of the process, and without additional fabrication processing, this structure achieves the widest impedance bandwidth at W-band and one of the highest gain and gain bandwidth. It is noteworthy that this is achieved with an extremely thin antenna substrate thickness and a shielding ground plane.
Autors: Pan, S.;Caster, F.;Heydari, P.;Capolino, F.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2014, volume: 62, issue:9, pages: 4439 - 4451
Publisher: IEEE
 
» A -Band Four-Element Butler Matrix in 0.13 µm SiGe BiCMOS Technology
Abstract:
This paper presents the design and characterization of a 220–240 GHz four-element Butler matrix beam switching chip. It is realized in 0.13 µm SiGe BiCMOS technology. The chip features four 220 GHz amplifiers with 9 dB of gain followed by the Butler matrix core. A single-pole-four-throw (SP4T) switch is integrated to switch between the different beam directions. Finally an amplifier is used to compensate the losses of the matrix core and the switch. The chip exhibits a 2 dB of insertion loss and draws 104 mA from a 3.3 V supply. It also shows maximum phase error of 15° from the ideal phase states and less than 4 dB rms amplitude variations. The chip occupies 1.5 × 2.4 mm 2 silicon area.
Autors: Elkhouly, M.;Mao, Y.;Meliani, C.;Scheytt, J.C.;Ellinger, F.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2014, volume: 49, issue:9, pages: 1916 - 1926
Publisher: IEEE
 
» A Biology-Based Algorithm to Minimal Exposure Problem of Wireless Sensor Networks
Abstract:
The Minimal Exposure Problem (MEP), which corresponds to the quality of coverage, is a fundamental problem in wireless sensor networks. This paper exploits a biological model of physarum to design a novel biology-inspired optimization algorithm for MEP. We first formulate MEP and the related models, and then convert MEP into the Steiner problem by discretizing the monitoring field to a large-scale weighted grid. Inspired by the path-finding capability of physarum, we develop a biological optimization solution to find the minimal exposure road-network among multiple points of interest, and present a Physarum Optimization Algorithm (POA). Furthermore, POA can be used for solving the general Steiner problem. Extensive simulations demonstrate that our proposed models and algorithm are effective for finding the road-network with minimal exposure and feasible for the Steiner problem.
Autors: Song, Y.;Liu, L.;Ma, H.;Vasilakos, A.V.;
Appeared in: IEEE Transactions on Network and Service Management
Publication date: Sep 2014, volume: 11, issue:3, pages: 417 - 430
Publisher: IEEE
 
» A biomimetic projector with high subwavelength directivity based on dolphin biosonar
Abstract:
Based on computed tomography of a Yangtze finless porpoise's biosonar system, a biomimetic structure was designed to include air cavity, gradient-index material, and steel outer-structure mimicking air sacs, melon, and skull, respectively. The mainlobe pressure was about three times higher, the angular resolution was one order of magnitude higher, and the effective source size was orders of magnitude larger than those of the subwavelength source without the biomimetic structure. The superior subwavelength directivity over a broad bandwidth suggests potential applications of this biomimetic projector in underwater sonar, medical ultrasonography, and other related applications.
Autors: Zhang, Yu;Gao, Xiaowei;Zhang, Sai;Cao, Wenwu;Tang, Liguo;Wang, Ding;Li, Yan;
Appeared in: Applied Physics Letters
Publication date: Sep 2014, volume: 105, issue:12, pages: 123502 - 123502-4
Publisher: IEEE
 
» A Broadband Dual-Polarized Planar Antenna for 2G/3G/LTE Base Stations
Abstract:
A broadband dual-polarized planar antenna is proposed for 2G/3G/LTE base stations. The dual-polarized antenna is composed of two perpendicularly crossed bow-tie dipoles. Each bow-tie dipole is excited by a microstrip stub that is directly fed by a coaxial line, making the dual-polarized antenna full planar. Due to the coupling between two crossed bow-tie dipoles, a broad bandwidth is achieved. It is shown that the dual-polarized antenna has a bandwidth of 45% (1.7–2.7 GHz) for return loss 15 dB with an isolation of higher than 30 dB between two polarization input ports. The dual-polarized antenna has a half-power beam width (HPBW) of around 65 and an average gain of 8.5 dBi for slant polarizations. An 8-element dual-polarized planar antenna array is developed for base station applications. A bandwidth of 56% (1.63–2.9 GHz) is obtained for the antenna array. The antenna gain of the array is about 16 dBi and the HPBW is for each polarization.
Autors: Cui, Y.;Li, R.;Fu, H.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2014, volume: 62, issue:9, pages: 4836 - 4840
Publisher: IEEE
 
» A broadband microwave Corbino spectrometer at 3He temperatures and high magnetic fields
Abstract:
We present the technical details of a broadband microwave spectrometer for measuring the complex conductance of thin films covering the range from 50 MHz up to 16 GHz in the temperature range 300 mK–6 K and at applied magnetic fields up to 8 T. We measure the complex reflection from a sample terminating a coaxial transmission line and calibrate the signals with three standards with known reflection coefficients. Thermal isolation of the heat load from the inner conductor is accomplished by including a section of NbTi superconducting cable (transition temperature around 8–9 K) and hermetic seal glass bead adapters. This enables us to stabilize the base temperature of the sample stage at 300 mK. However, the inclusion of this superconducting cable complicates the calibration procedure. We document the effects of the superconducting cable on our calibration procedure and the effects of applied magnetic fields and how we control the temperature with great repeatability for each measurement. We have successfully extracted reliable data in this frequency, temperature, and field range for thin superconducting films and highly resistive graphene samples.
Autors: Liu, Wei;Pan, LiDong;Armitage, N.P.;
Appeared in: Review of Scientific Instruments
Publication date: Sep 2014, volume: 85, issue:9, pages: 093108 - 093108-7
Publisher: IEEE
 
» A Broadband V-Band Rectangular Waveguide to Substrate Integrated Waveguide Transition
Abstract:
A broadband air-filled rectangular waveguide to substrate integrated waveguide (SIW) transition is proposed at V-band. By introducing an aperture coupled patch antenna structure into the design, a bandwidth wider than 35% for dB is achieved. A back-to-back prototype fabricated by the low-cost printed circuit board (PCB) technology shows that the insertion loss of a single transition is less than 0.58 dB within the bandwidth. With good performance and compact volume, the proposed transition is attractive for millimeter-wave circuit designs and measurements.
Autors: Li, Y.;Luk, K.-M.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Sep 2014, volume: 24, issue:9, pages: 590 - 592
Publisher: IEEE
 
» A Business Model for Multimedia Streaming in Mobile Clouds
Abstract:
In the last few years, the proliferation of mobile devices coupled with the ever-increasing popularity of multimedia applications, has stimulated great interest of new figures of service providers. The major objective is to offer mobile users, located in limited areas, with broadband multimedia applications enriched with services and functionalities specific to mobile scenarios. This is the case, for example, of passengers waiting to board in an airport, visitors to a museum, or spectators at a football stadium. Since cellular networks usually cannot deliver bitrates suitable for such kinds of applications to every single user, the most appealing solution for providing mobile users with multimedia applications is to organize users into mobile clouds. In this context, this paper considers delay-constrained multimedia streaming applications over mobile clouds, and defines a business model for managing these kinds of services. Users are divided into two classes, according to the way they intend to pay for the service: in bandwidth and energy for traffic relaying (cheap-tariff) or with some money (full-tariff). An analytical model is proposed for designing the main system parameters and deciding on the tariffs of the business model. Finally, the business model is applied to a case study.
Autors: Schembra, G.;Incarbone, G.;
Appeared in: IEEE Transactions on Network and Service Management
Publication date: Sep 2014, volume: 11, issue:3, pages: 376 - 389
Publisher: IEEE
 
» A Changing Climate: Data Show Warming Trends Ahead [From the Editor]
Abstract:
Discusses trends in global warming and asseses the implications for the power and electricity supply industry worldwide.
Autors: Olken, M.;
Appeared in: IEEE Power and Energy Magazine
Publication date: Sep 2014, volume: 12, issue:5, pages: 4 - 6
Publisher: IEEE
 
» A Clarification of the Proper-Integral Form for the Gaussian -Function and Some New Results Involving the -Function
Abstract:
We discuss the origin of the well-known integral form for the Gaussian -function. Although this form is originally attributed to Craig in his 1991 paper, it actually was inferred in previous communications theory references in the literature by Weinstein, and explicitly stated by Pawula, Rice and Roberts. Specifically, this form can be seen as a particular case of the general -function, that is related to the distribution of the phase angle between two vectors perturbed by Gaussian noise. We show that the -function includes as particular cases the one- and two-dimensional Gaussian -functions, and is connected with a class of confluent hypergeometric functions through the multivariate function. This connection generalizes the existing relation between the Gaussian -functions and this family of hypergeometric functions.
Autors: Lopez-Martinez, F.J.;Pawula, R.F.;Martos-Naya, E.;Paris, J.F.;
Appeared in: IEEE Communications Letters
Publication date: Sep 2014, volume: 18, issue:9, pages: 1495 - 1498
Publisher: IEEE
 
» A Class of Position Controllers for Underactuated VTOL Vehicles
Abstract:
This technical note proposes a unified framework for stabilizing a hover equilibrium for a class of vertical take-off and landing (VTOL) aircraft using a cascade control architecture which yields almost global stability in the absence of wind gusts. The control design process is partitioned into two decoupled parts: the design of a bounded position controller for a fully actuated point-mass particle, and the design of an attitude stabilizer. The position feedback is then used in an outer loop to provide reference signals for the inner loop attitude stabilizer. A number of sample feedbacks in the proposed controller class are presented, some of which include integral action to compensate for an unknown mass.
Autors: Roza, A.;Maggiore, M.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Sep 2014, volume: 59, issue:9, pages: 2580 - 2585
Publisher: IEEE
 
» A closed-form capacitance model for tunnel FETs with explicit surface potential solutions
Abstract:
In this paper, a closed-form physical capacitance model for bulk tunnel FETs (TFETs) is proposed based on the surface potential approach for the first time. Fundamentally different from that in the MOSFET, the channel surface potential φsf in the TFET is alternately controlled by the drain bias and gate bias in different operation regions. On the basis of physical insight into the operation mechanism, the analytical model of φsf as a function of terminal bias is established. The Gaussian box is introduced to predict the surface potential profile near the source-body junction. Furthermore, the surface-potential-based capacitance model is derived and the calculated terminal capacitances show good agreement with the TCAD simulation results. With the essential physics considered, excellent validity of the model is achieved for bulk TFETs with a large range of structure parameters and SOI/double-gate (DG) TFETs.
Autors: Wang, Jiaxin;Wu, Chunlei;Huang, Qianqian;Wang, Chao;Huang, Ru;
Appeared in: Journal of Applied Physics
Publication date: Sep 2014, volume: 116, issue:9, pages: 094501 - 094501-8
Publisher: IEEE
 
» A Closing Circle: Back to Authoring
Abstract:
Since the turn of this century, we have seen striking developments in multimedia technologies that let communication means flourish, through which people now can easily share their interests, opinions, visions, prejudices, hopes, fears, fetishes, the here and now, their inner state in measurement, or simply glimpses of the richness or boredom of their everyday lives. These technologies have revolutionized people's lives by altering the ways they learn, investigate, negotiate, and argument in public and private as well as how they meet, date, and befriend. In this reflective piece, Frank Nack argues that, for the development of multimedia technologies, social media research should focus on the interaction and communication basics of the different media and how they can be added into representations that actually help to improve human communication in digital environments.
Autors: Nack, Frank;
Appeared in: IEEE Multimedia
Publication date: Sep 2014, volume: 21, issue:3, pages: 4 - 6
Publisher: IEEE
 
» A CMOS LNA Using a Harmonic Rejection Technique to Enhance Its Linearity
Abstract:
In this study, we design a differential low-noise amplifier (LNA) using a 0.18- RF CMOS process. To improve its linearity, we propose a harmonic rejection technique using RC feedback at the gain stage. The third harmonic component of the drain node of the common-gate transistor is fed back to the source node of the common-gate transistor to restrict the generation of the third harmonic component at the output of the LNA. To verify the feasibility of the proposed technique for a linear amplifier, we designed a typical LNA and the proposed LNA in an identical process and with the same design parameters apart from the feedback loop of the proposed LNA. The measured improvement of the input-referred P1 dB of the proposed LNA is approximately 3 dB compared to that of the typical LNA. From these measured results, we successfully prove the feasibility of the proposed linearization technique.
Autors: Yoon, J.;Park, C.;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Sep 2014, volume: 24, issue:9, pages: 605 - 607
Publisher: IEEE
 
» A combined kick-out and dissociative diffusion mechanism of grown-in Be in InGaAs and InGaAsP. A new finite difference-Bairstow method for solution of the diffusion equations
Abstract:
Experimental results on the diffusion of grown-in beryllium (Be) in indium gallium arsenide (In0.53Ga0.47As) and indium gallium arsenide phosphide (In0.73Ga0.27As0.58P0.42) gas source molecular beam epitaxy alloys lattice-matched to indium phosphide (InP) can be successfully explained in terms of a combined kick-out and dissociative diffusion mechanism, involving neutral Be interstitials (Bei0), singly positively charged gallium (Ga), indium (In) self-interstitials (IIII+) and singly positively charged Ga, In vacancies (VIII+). A new numerical method of solution to the system of diffusion equations, based on the finite difference approximations and Bairstow's method, is proposed.
Autors: Koumetz, Serge D.;Martin, Patrick;Murray, Hugues;
Appeared in: Journal of Applied Physics
Publication date: Sep 2014, volume: 116, issue:10, pages: 103701 - 103701-13
Publisher: IEEE
 
» A Comment on “Short Channel Hopping Sequence Approach to Rendezvous for Cognitive Networks”
Abstract:
Recently, Reguera et al. proposed a channel hopping scheme called short-sequence-based (SSB) rendezvous algorithm which works under symmetric and asymmetric channel models. After our revisit of the SSB implementation under the asymmetric model, we found that some cases will fail to have rendezvous in the asynchronous environment and the performance of SSB cannot be guaranteed as one would expect. In addition, we propose a conjecture for the failing cases.
Autors: Ke, C.;Sheu, J.;
Appeared in: IEEE Communications Letters
Publication date: Sep 2014, volume: 18, issue:9, pages: 1631 - 1632
Publisher: IEEE
 
» A Communication Theoretical Analysis of FRET-Based Mobile Ad Hoc Molecular Nanonetworks
Abstract:
Nanonetworks refer to a group of nanosized machines with very basic operational capabilities communicating to each other in order to accomplish more complex tasks such as in-body drug delivery, or chemical defense. Realizing reliable and high-rate communication between these nanomachines is a fundamental problem for the practicality of these nanonetworks. Recently, we have proposed a molecular communication method based on Förster Resonance Energy Transfer (FRET) which is a nonradiative excited state energy transfer phenomenon observed among fluorescent molecules, i.e., fluorophores. We have modeled the FRET-based communication channel considering the fluorophores as single-molecular immobile nanomachines, and shown its reliability at high rates, and practicality at the current stage of nanotechnology. In this study, for the first time in the literature, we investigate the network of mobile nanomachines communicating through FRET. We introduce two novel mobile molecular nanonetworks: FRET-based mobile molecular sensor/actor nanonetwork (FRET-MSAN) which is a distributed system of mobile fluorophores acting as sensor or actor node; and FRET-based mobile ad hoc molecular nanonetwork (FRET-MAMNET) which consists of fluorophore-based nanotransmitter, nanoreceivers and nanorelays. We model the single message propagation based on birth-death processes with continuous time Markov chains. We evaluate the performance of FRET-MSAN and FRET-MAMNET in terms of successful transmission probability and mean extinction time of the messages, system throughput, channel capacity and achievable communication rates.
Autors: Kuscu, M.;Akan, O.B.;
Appeared in: IEEE Transactions on NanoBioscience
Publication date: Sep 2014, volume: 13, issue:3, pages: 255 - 266
Publisher: IEEE
 
» A Compact and Low-Power Fractionally Injection-Locked Quadrature Frequency Synthesizer Using a Self-Synchronized Gating Injection Technique for Software-Defined Radios
Abstract:
Pub DtlThis paper describes a compact and low-power frequency synthesizer with quadrature phase output for software-defined radios (SDRs). The proposed synthesizer is constructed using a core phase-locked loop (PLL), which is coupled with a fractional-N injection-locked frequency divider (ILFD). The fractional-N injection-locking operation is achieved by the proposed self-synchronized gating injection technique. The principle of a fractional-N injection locking operation and the concept of the proposed circuits are described in detail. Analysis for predicting the locking range of the proposed fractional-N ILFD is investigated. A digital calibration scheme is adopted in order to compensate for process, voltage, and temperature (PVT) variations. Implemented in a 65 nm CMOS process, this work demonstrates continuous frequency coverage from 10 MHz to 6.6 GHz with quadrature phase output while occupying a small area of 0.38 mm 2 and consuming 16 to 26 mW, depending on the output frequency. The normalized phase noise achieves -135.3 dBc/Hz at an offset of 3 MHz and -95.1 dBc/Hz at an offset of 10 kHz, both from a carrier frequency of 1.7 GHz.
Autors: Deng, W.;Hara, S.;Musa, A.;Okada, K.;Matsuzawa, A.;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Sep 2014, volume: 49, issue:9, pages: 1984 - 1994
Publisher: IEEE
 
» A Compact Explicit Model for Long-Channel Gate-All-Around Junctionless MOSFETs. Part I: DC Characteristics
Abstract:
In this paper, we solved Poisson equation in cylindrical coordinates using approximations to obtain a compact model for the drain current of long-channel junctionless gate-all-around MOSFETs. The resulting model is analytical, explicit, and valid for depletion and accumulation, and consists of simple physically based equations, for better understanding of this device, and also easier implementation and better computation speed as a compact model. The agreement with TCAD simulations is very good.
Autors: Lime, F.;Moldovan, O.;Iniguez, B.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2014, volume: 61, issue:9, pages: 3036 - 3041
Publisher: IEEE
 
» A compact relativistic backward-wave oscillator with metallized plastic components
Abstract:
This letter presents the mechanism and realization of a compact relativistic backward-wave oscillator with metallized plastic components. The physical idea, specific structure, and the main testing results are presented. The three periods slow-wave structures with both inner and outer ripples and the coaxial extractor are designed to reduce the volume and increase the efficiency of the device. The metallized plastic components replacing the stainless steel components in the high power microwave (HPM) sources are put forward to reduce the device weight. In the initial experiment, a microwave with frequency of 1.54 GHz, power of 1.97 GW, efficiency of 33.5%, and pulse duration above 47 ns is generated, which proves that this technical route is feasible. Undoubtedly, the technical route can provide a guide to design other types of HPM sources and be benefit to the practical application of the compact HPM systems.
Autors: Ge, Xingjun;Zhang, Jun;Zhong, Huihuang;Qian, Baoliang;
Appeared in: Applied Physics Letters
Publication date: Sep 2014, volume: 105, issue:12, pages: 123501 - 123501-4
Publisher: IEEE
 
» A Comparative Review of Component Tree Computation Algorithms
Abstract:
Connected operators are morphological tools that have the property of filtering images without creating new contours and without moving the contours that are preserved. Those operators are related to the max-tree and min-tree representations of images, and many algorithms have been proposed to compute those trees. However, no exhaustive comparison of these algorithms has been proposed so far, and the choice of an algorithm over another depends on many parameters. Since the need for fast algorithms is obvious for production code, we present an in-depth comparison of the existing algorithms in a unique framework, as well as variations of some of them that improve their efficiency. This comparison involves both sequential and parallel algorithms, and execution times are given with respect to the number of threads, the input image size, and the pixel value quantization. Eventually, a decision tree is given to help the user choose the most appropriate algorithm with respect to the user requirements. To favor reproducible research, an online demo allows the user to upload an image and bench the different algorithms, and the source code of every algorithms has been made available.
Autors: Carlinet, E.;Geraud, T.;
Appeared in: IEEE Transactions on Image Processing
Publication date: Sep 2014, volume: 23, issue:9, pages: 3885 - 3895
Publisher: IEEE
 
» A comparative study of spin coated and floating film transfer method coated poly (3-hexylthiophene)/poly (3-hexylthiophene)-nanofibers based field effect transistors
Abstract:
A comparative study on electrical performance, optical properties, and surface morphology of poly(3-hexylthiophene) (P3HT) and P3HT-nanofibers based “normally on” type p-channel field effect transistors (FETs), fabricated by two different coating techniques has been reported here. Nanofibers are prepared in the laboratory with the approach of self-assembly of P3HT molecules into nanofibers in an appropriate solvent. P3HT (0.3 wt. %) and P3HT-nanofibers (∼0.25 wt. %) are used as semiconductor transport materials for deposition over FETs channel through spin coating as well as through our recently developed floating film transfer method (FTM). FETs fabricated using FTM show superior performance compared to spin coated devices; however, the mobility of FTM films based FETs is comparable to the mobility of spin coated one. The devices based on P3HT-nanofibers (using both the techniques) show much better performance in comparison to P3HT FETs. The best performance among all the fabricated organic field effect transistors are observed for FTM coated P3HT-nanofibers FETs. This improved performance of nanofiber-FETs is due to ordering of fibers and also due to the fact that fibers offer excellent charge transport facility because of point to point transmission. The optical properties and structural morphologies (P3HT and P3HT-nanofibers) are studied using UV-visible absorption spectrophotometer and atomic force microscopy , respectively. Coating techniques and effect of fiber formation for organic conductors give information for fabrication of organic devices with improved performance.
Autors: Tiwari, Shashi;Takashima, Wataru;Nagamatsu, S.;Balasubramanian, S.K.;Prakash, Rajiv;
Appeared in: Journal of Applied Physics
Publication date: Sep 2014, volume: 116, issue:9, pages: 094306 - 094306-7
Publisher: IEEE
 
» A comparison of the voltage withstand properties of ester and mineral oils
Abstract:
The growing price of mineral oils (MOs) over the last 15 years, and environmental and safety concerns, have promoted research on alternative insulating fluids. Ester oils (EOs), which were used initially in transformer insulation [1], have again attracted attention; both synthetic and natural liquids have been investigated thoroughly in the search for suitable substitutes for MOs. EOs have interesting properties [1]. Their most attractive properties are those concerning flammability; depending on their chemical structure, their fire points are 100??C to 200??C higher than those of MOs, which ensures that fires are less likely in EO-filled transformers. They are also biodegradable, a property that has favored their use in environments where oil spills cannot be easily confined, e.g., traction and off-shore transformers. They are also much more hygroscopic than MOs, a property which favors drying of solid insulation, thus ensuring that depolymerization of cellulose is slowed down. This improves the long-term mechanical stability of transformer solid insulation.
Autors: Azcarraga, C.G.;Cavallini, A.;Piovan, U.;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Sep 2014, volume: 30, issue:5, pages: 6 - 14
Publisher: IEEE
 
» A Comprehensive Study of Sampling-Based Optimum Signal Detection in Concentration-Encoded Molecular Communication
Abstract:
In this paper, a comprehensive analysis of the sampling-based optimum signal detection in ideal (i.e., free) diffusion-based concentration-encoded molecular communication (CEMC) system has been presented. A generalized amplitude-shift keying (ASK)-based CEMC system has been considered in diffusion-based noise and intersymbol interference (ISI) conditions. Information is encoded by modulating the amplitude of the transmission rate of information molecules at the TN. The critical issues involved in the sampling-based receiver thus developed are addressed in detail, and its performance in terms of the number of samples per symbol, communication range, and transmission data rate is evaluated. ISI produced by the residual molecules deteriorates the performance of the CEMC system significantly, which further deteriorates when the communication range and/or the transmission data rate increase(s). In addition, the performance of the optimum receiver depends on the receiver's ability to compute the ISI accurately, thus providing a trade-off between receiver complexity and achievable bit error rate (BER). Exact and approximate detection performances have been derived. Finally, it is found that the sampling-based signal detection scheme thus developed can be applied to both binary and multilevel (M-ary) ASK-based CEMC systems, although M-ary systems suffer more from higher BER.A small part of this paper was peer-reviewed, presented at, and published in the proceedings of BIOSIGNALS-2013 conference in Barcelona, Spain, during 11-14 February, 2013, DOI: 10.5220/0004305403720376 .
Autors: Mahfuz, M.U.;Makrakis, D.;Mouftah, H.T.;
Appeared in: IEEE Transactions on NanoBioscience
Publication date: Sep 2014, volume: 13, issue:3, pages: 208 - 222
Publisher: IEEE
 
» A Computational Model of Plan-Based Narrative Conflict at the Fabula Level
Abstract:
Pub DtlConflict is an essential element of interesting stories. In this paper, we operationalize a narratological definition of conflict and extend established narrative planning techniques to incorporate this definition. The conflict partial order causal link planning algorithm (CPOCL) allows narrative conflict to arise in a plan while maintaining causal soundness and character believability. We also define seven dimensions of conflict in terms of this algorithm's knowledge representation. The first three—participants, reason, and duration—are discrete values which answer the “who?” “why?” and “when?” questions, respectively. The last four—balance, directness, stakes, and resolution—are continuous values which describe important narrative properties that can be used to select conflicts based on the author's purpose. We also present the results of two empirical studies which validate our operationalizations of these narrative phenomena. Finally, we demonstrate the different kinds of stories which CPOCL can produce based on constraints on the seven dimensions.
Autors: Ware, S.G.;Young, R.M.;Harrison, B.;Roberts, D.L.;
Appeared in: IEEE Transactions on Computational Intelligence and AI in Games
Publication date: Sep 2014, volume: 6, issue:3, pages: 271 - 288
Publisher: IEEE
 
» A Computationally Efficient Design Technique for Electric-Vehicle Traction Machines
Abstract:
This paper describes a new design technique for electric-vehicle traction machines in order to achieve high efficiency against a defined driving cycle such as the New European Drive Cycle, while satisfying the required torque–speed operating range and other volumetric and thermal design constraints. This paper is undertaken as a part of the Personal Mobility Project funded by the European Union. By analyzing the energy distribution of a given driving cycle, the energy efficiency of the traction machine over the driving cycle can be characterized against a number of representative points, and the design optimization can be carried out with respect to these points. This dramatically reduces the computation time of the design optimization process, while improving the energy efficiency of the traction machines. The utility of the design technique has been illustrated through design case studies and its effectiveness validated by experimental results.
Autors: Lazari, P.;Wang, J.;Chen, L.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Sep 2014, volume: 50, issue:5, pages: 3203 - 3213
Publisher: IEEE
 
» A Computing Framework of Adaptive Support-Window Multi-Lateral Filter for Image and Depth Processing
Abstract:
In this paper, a computing framework for adaptive-support-window-based multi-lateral filters is proposed. The so-called multi-lateral filters, extended from the well-known bilateral filter, have found their broaden applications in noise/high-frequency suppression for 2-D image and 3-D depth processing. Our filters rely on binarizing the traditional pixel-wise weights to be only 0 or 1, resulting in an adaptive support window whose shape depends on the local image structure of the central anchor pixel. A cross-subwindow-based algorithm is devised to compute the adaptive support window. A fast algorithm based on integral images is also devised for data aggregation within such an irregularly shaped support window. Taking advantage of the integral images, our scheme presents a near constant-time complexity regardless of the size and shape of the support window. Experiments show that both noise suppression and edge-preserving can be simultaneously achieved by using our proposed framework. The average speedup ratios of our scheme are 14X and 1.3X against the traditional and the O(1) implementations, respectively. Our scheme also has the advantage of easy extension to tri-lateral and quadri-lateral filters, whereas other O(1) algorithms might not.
Autors: Lin, G.;Chen, C.;Kuo, C.;Lie, W.;
Appeared in: IEEE Transactions on Broadcasting
Publication date: Sep 2014, volume: 60, issue:3, pages: 452 - 463
Publisher: IEEE
 
» A Conductive AFM Nanoscale Analysis of NBTI and Channel Hot-Carrier Degradation in MOSFETs
Abstract:
This paper addresses the impact of different electrical stresses on nanoscale electrical properties of the MOSFET gate dielectric. Using a conductive atomic force microscope (CAFM) for the first time, the gate oxide has been analyzed after bias temperature instability (BTI) and channel hot-carrier (CHC) stresses. The CAFM explicitly shows that while the degradation induced along the channel by a negative BTI stress is homogeneous, after a CHC stress different degradation levels can be distinguished, being higher close to source and drain.
Autors: Wu, Q.;Bayerl, A.;Porti, M.;Martin-Martinez, J.;Lanza, M.;Rodriguez, R.;Velayudhan, V.;Nafria, M.;Aymerich, X.;Gonzalez, M.B.;Simoen, E.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2014, volume: 61, issue:9, pages: 3118 - 3124
Publisher: IEEE
 
» A Converse Lyapunov Theorem and Robustness for Asymptotic Stability in Probability
Abstract:
A converse Lyapunov theorem is established for discrete-time stochastic systems with non-unique solutions. In particular, it is shown that global asymptotic stability in probability implies the existence of a continuous Lyapunov function, smooth outside of the attractor, that decreases in expected value along solutions. The keys to this result are mild regularity conditions imposed on the set-valued mapping that characterizes the update of the system state, and the ensuing robustness of global asymptotic stability in probability to sufficiently small state-dependent perturbations.
Autors: Teel, A.R.;Hespanha, J.P.;Subbaraman, A.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Sep 2014, volume: 59, issue:9, pages: 2426 - 2441
Publisher: IEEE
 
» A Cooperative Parallel Search-Based Software Engineering Approach for Code-Smells Detection
Abstract:
We propose in this paper to consider code-smells detection as a distributed optimization problem. The idea is that different methods are combined in parallel during the optimization process to find a consensus regarding the detection of code-smells. To this end, we used Parallel Evolutionary algorithms (P-EA) where many evolutionary algorithms with different adaptations (fitness functions, solution representations, and change operators) are executed, in a parallel cooperative manner, to solve a common goal which is the detection of code-smells. An empirical evaluation to compare the implementation of our cooperative P-EA approach with random search, two single population-based approaches and two code-smells detection techniques that are not based on meta-heuristics search. The statistical analysis of the obtained results provides evidence to support the claim that cooperative P-EA is more efficient and effective than state of the art detection approaches based on a benchmark of nine large open source systems where more than 85 percent of precision and recall scores are obtained on a variety of eight different types of code-smells.
Autors: Kessentini, W.;Kessentini, M.;Sahraoui, H.;Bechikh, S.;Ouni, A.;
Appeared in: IEEE Transactions on Software Engineering
Publication date: Sep 2014, volume: 40, issue:9, pages: 841 - 861
Publisher: IEEE
 
» A Coordinated Design of PSSs and UPFC-based Stabilizer Using Genetic Algorithm
Abstract:
This paper details a new coordinated design between power system stabilizers (PSSs) and a unified power flow controller (UPFC) using genetic algorithms (GAs). A GA scheme determines the optimal location for a UPFC while tuning its control parameters, resulting in the optimization of the quantity, parameters, and locations of PSSs under different operating conditions. The problem is formulated as a multiobjective optimization problem in order to maximize the damping ratio(s) of electromechanical modes, matching different numbers of PSSs with a UPFC. The approach is successfully tested on the New England–New York interconnected system (a 16-machine and 68-bus system), proving its effectiveness in damping local and interarea modes of oscillations.
Autors: Hassan, L.H.;Moghavvemi, M.;Almurib, H.A.F.;Muttaqi, K.M.;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Sep 2014, volume: 50, issue:5, pages: 2957 - 2966
Publisher: IEEE
 
» A cryogen-free ultralow-field superconducting quantum interference device magnetic resonance imaging system
Abstract:
Magnetic resonance imaging (MRI) at microtesla fields using superconducting quantum interference device (SQUID) detection has previously been demonstrated, and advantages have been noted. Although the ultralow-field SQUID MRI technique would not need the heavy superconducting magnet of conventional MRI systems, liquid helium required to cool the low-temperature detector still places a significant burden on its operation. We have built a prototype cryocooler-based SQUID MRI system that does not require a cryogen. The SQUID detector and the superconducting gradiometer were cooled down to 3.7 K and 4.3 K, respectively. We describe the prototype design, characterization, a phantom image, and areas of further improvements needed to bring the imaging performance to parity with conventional MRI systems.
Autors: Eom, Byeong Ho;Penanen, Konstantin;Hahn, Inseob;
Appeared in: Review of Scientific Instruments
Publication date: Sep 2014, volume: 85, issue:9, pages: 094302 - 094302-9
Publisher: IEEE
 
» A Device for Emulating Cuff Recordings of Action Potentials Propagating Along Peripheral Nerves
Abstract:
This paper describes a device that emulates propagation of action potentials along a peripheral nerve, suitable for reproducible testing of bio-potential recording systems using nerve cuff electrodes. The system is a microcontroller-based stand-alone instrument which uses established nerve and electrode models to represent neural activity of real nerves recorded with a nerve cuff interface, taking into consideration electrode impedance, voltages picked up by the electrodes, and action potential propagation characteristics. The system emulates different scenarios including compound action potentials with selectable propagation velocities and naturally occurring nerve traffic from different velocity fiber populations. Measured results from a prototype implementation are reported and compared with in vitro recordings from Xenopus Laevis frog sciatic nerve, demonstrating that the electrophysiological setting is represented to a satisfactory degree, useful for the development, optimization and characterization of future recording systems.
Autors: Rieger, R.;Schuettler, M.;Chuang, S.-C.;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Sep 2014, volume: 22, issue:5, pages: 937 - 945
Publisher: IEEE
 
» A Distributed Direct Load Control Approach for Large-Scale Residential Demand Response
Abstract:
This paper proposes a distributed direct load control scheme for large-scale residential demand response (DR) built on a two-layer communication-based control architecture. The lower-layer network is within each building, where the energy management controller (EMC) uses wireless links to schedule operation of appliances upon request according to a local power consumption target. The upper-layer network links a number of EMCs in a region whose aggregated demand is served by a load aggregator. The load aggregator wants the actual aggregated demand over this region to match a desired aggregated demand profile. Our approach utilizes the average consensus algorithm to distribute portions of the desired aggregated demand to each EMC in a decentralized fashion. The allocated portion corresponds to each building's aforementioned local power consumption target which its EMC then uses to schedule the in-building appliances. The result will be an aggregated demand over this region that more closely reaches the desired demand. Numerical results show that our scheme can alleviate the mismatch between the actual aggregated demand and the desired aggregated demand profile.
Autors: Chen, C.;Wang, J.;Kishore, S.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2014, volume: 29, issue:5, pages: 2219 - 2228
Publisher: IEEE
 
» A Dual-Polarized Wideband Planar Phased Array With Spiral Antennas
Abstract:
The design of a wide bandwidth dual-polarized phased array of Archimedean spiral antennas with cavity is presented. The reflection coefficient, circular polarization and grating lobes are addressed independently in the design process. Uniform concentric rings array is used to control the grating lobes, thanks to its non uniform spatial distribution, and obtain a good circular polarization, thanks to its rotational symmetry. Simulations of one-ring array agree with the measurements. Adding more rings keeps the side lobes level to less than 10 dB, relative to the main lobe. The dual-polarized array can scan up to keeping a low reflection coefficient and low side lobe levels.
Autors: Hinostroza Saenz, I.D.;Guinvarc'h, R.;Haupt, R.L.;Louertani, K.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Sep 2014, volume: 62, issue:9, pages: 4547 - 4553
Publisher: IEEE
 
» A Dynamic Compression Scheme for Energy-Efficient Real-Time Wireless Electrocardiogram Biosensors
Abstract:
Wireless body sensor networks enabled electrocardiogram (ECG) biosensors are a novel solution for patient-centric telecardiology. With this solution, the prevention and early diagnosis of cardiovascular diseases can be effectively improved. However, the energy efficiency of the present wireless ECG biosensors still needs to be improved. In this paper, a dynamic compression scheme is proposed to deal with the challenge of ultralow power and real-time wireless ECG application. This compression scheme consists of a digital integrate-and-fire sampler and a lossless entropy encoder, which can reduce airtime over energy-hungry wireless links and improve the energy efficiency of the biosensors. The efficiency improvement is evidenced by the experiments using the MIT-BIH arrhythmia database in MICAz node. The lifetime of dc-implemented MICAz node can be extended up to 76.60% with high signal recovery quality. This scheme is also compared with the digital wavelet transform-based and compressed sensing-based compression schemes. All experimental results indicate that the proposed scheme has high-energy efficiency, low computational complexity, less resource consumption, and rapid time response.
Autors: Luo, K.;Li, J.;Wu, J.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Sep 2014, volume: 63, issue:9, pages: 2160 - 2169
Publisher: IEEE
 
» A Fast Anticollision Algorithm for the EPCglobal UHF Class-1 Generation-2 RFID Standard
Abstract:
In this letter, a fast anticollision algorithm has been proposed to improve the read performance of the EPCglobal UHF Class-1 Generation-2 protocol. Our algorithm is based on the early adjustment of frame length. To reduce the computation complexity of interrogators, the proposed algorithm resorts to only one examination of current frame length in each read round. As compared with the case of examining at every time slot, the proposed method can dramatically reduce the number of examinations from about 1425 to 14. The normalized throughput of our method can reach a value of up to 35%, which is very close to the theoretical maximum of 36% for the EPCglobal UHF Class-1 Generation-2 anticollision scheme.
Autors: Chen, W.;
Appeared in: IEEE Communications Letters
Publication date: Sep 2014, volume: 18, issue:9, pages: 1519 - 1522
Publisher: IEEE
 
» A Fast Settling Phase Modulator for Outphasing Transmitters in 65-nm CMOS
Abstract:
We present a phase modulator architecture with very fast settling time for use in high data-rate outphasing transmitters. The proposed design utilizes the phase-shifting capabilities of a resonant tank and the ability to separately control the circuit properties via its components. A prototype in 65-nm CMOS achieves 9 bits of effective resolution, with a fast settling time of less than five carrier cycles to within 1 . The circuit is also tested as a standalone transmitter showing an error vector magnitude of less than 5% for 8-PSK modulation at maximum data rate of 240 Mb/s, meeting the Federal Communications Commission requirements for operation at the medical implant communication services band.
Autors: Yahalom, G.;Dawson, J.L.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Sep 2014, volume: 62, issue:9, pages: 2048 - 2058
Publisher: IEEE
 
» A Fast Technique to Screen Carrier Generation Lifetime Using DLTS on MOS Capacitors
Abstract:
We have developed a technique for fast screening of carrier generation lifetime in ultraclean silicon wafers by employing deep-level transient spectroscopy (DLTS) measurements on metal–oxide–semiconductor-capacitor (MOS-C) test structures. Results show that the screened lifetime is of sufficient accuracy to distinguish metallic impurities with densities as low as cm in thin p/p+ silicon epitaxial layers. The widely used classic pulsed MOS-C technique is shown to be inaccurate and unable to separate bulk and surface components of the lifetime, while its modified and more accurate versions are time consuming and unaffordable for process screening purposes.
Autors: Elhami Khorasani, A.;Schroder, D.K.;Alford, T.L.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Sep 2014, volume: 61, issue:9, pages: 3282 - 3288
Publisher: IEEE
 
» A field programmable gate array-based time-resolved scaler for collinear laser spectroscopy with bunched radioactive potassium beams
Abstract:
A new data acquisition system including a Field Programmable Gate Array (FPGA) based time-resolved scaler was developed for laser-induced fluorescence and beam bunch coincidence measurements. The FPGA scaler was tested in a collinear laser-spectroscopy experiment on radioactive 37K at the BEam COoler and LAser spectroscopy (BECOLA) facility at the National Superconducting Cyclotron Laboratory at Michigan State University. A 1.29 μs bunch width from the buncher and a bunch repetition rate of 2.5 Hz led to a background suppression factor of 3.1 × 105 in resonant photon detection measurements. The hyperfine structure of 37K and its isotope shift relative to the stable 39K were determined using 5 × 104 s−1 37K ions injected into the BECOLA beam line. The obtained hyperfine coupling constants A(2S1/2) = 120.3(1.4) MHz, A(2P1/2) = 15.2(1.1) MHz, and A(2P3/2) = 1.4(8) MHz, and the isotope shift δν39, 37 = −264(3) MHz are consistent with the previously determined values, where available.
Autors: Rossi, D.M.;Minamisono, K.;Barquest, B.R.;Bollen, G.;Cooper, K.;Davis, M.;Hammerton, K.;Hughes, M.;Mantica, P.F.;Morrissey, D.J.;Ringle, R.;Rodriguez, J.A.;Ryder, C.A.;Schwarz, S.;Strum, R.;Sumithrarachchi, C.;Tarazona, D.;Zhao, S.;
Appeared in: Review of Scientific Instruments
Publication date: Sep 2014, volume: 85, issue:9, pages: 093503 - 093503-6
Publisher: IEEE
 
» A Flexible Mixed-Integer Linear Programming Approach to the AC Optimal Power Flow in Distribution Systems
Abstract:
In this paper, we propose a flexible mixed-integer linear programming formulation of the AC OPF problem for distribution systems, using convexification and linearization techniques. The proposed formulation allows the representation of discrete decisions via integer decision variables, captures the nonlinear behavior of the electrical network via approximations of controllable accuracy, and can be solved to global optimality with commercial optimization solvers. The formulation is based on conventional variables that describe network behavior, which ensures its flexibility and the possibility of application to various distribution system problems, as we indicate with case studies.
Autors: Ferreira, R.S.;Borges, C.L.T.;Pereira, M.V.F.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2014, volume: 29, issue:5, pages: 2447 - 2459
Publisher: IEEE
 
» A Fourier-Based Approach to the Angiographic Assessment of Flow Diverter Efficacy in the Treatment of Cerebral Aneurysms
Abstract:
Flow diversion is an emerging endovascular treatment option for cerebral aneurysms. Quantitative assessment of hemodynamic changes induced by flow diversion can aid clinical decision making in the treatment of cerebral aneurysms. In this article, besides summarizing past key research efforts, we propose a novel metric for the angiographic assessment of flow diverter deployments in the treatment of cerebral aneurysms. By analyzing the frequency spectra of signals derived from digital subtraction angiography (DSA) series, the metric aims to quantify the prevalence of frequency components that correspond to the patient-specific heart rate. Indicating the decoupling of aneurysms from healthy blood circulation, our proposed metric could advance clinical guidelines for treatment success prediction. The very promising results of a retrospective feasibility study on 26 DSA series warrant future efforts to study the validity of the proposed metric within a clinical setting.
Autors: Benz, T.;Kowarschik, M.;Endres, J.;Redel, T.;Demirci, S.;Navab, N.;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Sep 2014, volume: 33, issue:9, pages: 1788 - 1802
Publisher: IEEE
 
» A Full Bayesian Approach for Masked Data in Step-Stress Accelerated Life Testing
Abstract:
Bayesian analysis of the series system failure data under step-stress accelerating life testing is proposed when the cause of failure may not have been identified but has only been narrowed down to a subset of all potential risks. A general Bayesian formulation is investigated for the log-location-scale distribution family that includes most commonly used parametric lifetime distributions. Reparameterization is introduced for estimating the lifetime under the use condition stress and other parameters directly. The posterior analysis is done by Markov chain Monte Carlo sampling. The methodology is illustrated through the Weibull distributions, and a numerical example.
Autors: Xu, A.;Basu, S.;Tang, Y.;
Appeared in: IEEE Transactions on Reliability
Publication date: Sep 2014, volume: 63, issue:3, pages: 798 - 806
Publisher: IEEE
 
» A Fully Adaptive PMU-Based Fault Location Algorithm for Series-Compensated Lines
Abstract:
This paper presents a fully adaptive fault location algorithm for series-compensated lines (SCLs) based on synchronized phasor measurements obtained by phasor measurement units (PMUs). The proposed algorithm does not require any knowledge on the exact model of the series-compensation device and, therefore, can be applied to transmission lines with any type of series compensation. In addition, the proposed algorithm utilizes only PMU synchronized measurements and does not require any data to be provided by the electric utility. The SCL parameters and Thevenin's equivalent (TE) of the system at SCL terminals are determined online, utilizing three independent sets of pre-fault PMU measurements, to ensure considering the actual operating conditions of the system. Fault-location accuracy evaluation of the proposed algorithm is performed with respect to various factors such as fault position, fault type, fault resistance, fault inception angle, pre-fault loading and line compensation degree. The proposed algorithm is simulated using both PSCAD/EMTDC and MATLAB and tested on a 400-kV system. Simulation results revealed that the developed algorithm is capable of producing reliable and highly accurate solutions.
Autors: Al-Mohammed, A.H.;Abido, M.A.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2014, volume: 29, issue:5, pages: 2129 - 2137
Publisher: IEEE
 
» A Fully Integrated Low-Power High-Coexistence 2.4-GHz ZigBee Transceiver for Biomedical and Healthcare Applications
Abstract:
A fully integrated low-power high-coexistence 2.4-GHz ZigBee transceiver implemented in 90-nm CMOS technology is demonstrated. The two-point direct-modulation with a fractional- synthesizer is adopted in the transmitter architecture. The transmitter can provide high output power of 9 dBm and excellent error vector magnitude of 5.1%. The direct conversion is used in receiver for simplicity and 97-dBm minimum receiver sensitivity is achieved. Current consumptions for a TX at 9-dBm output power and for an RX are 28.4 and 15.4 mA, respectively. Excellent coexistence is presented through wireless local area network interferer rejection performance.
Autors: Gil, J.;Kim, J.-H.;Kim, C.S.;Park, C.;Park, J.;Park, H.;Lee, H.;Lee, S.-J.;Jang, Y.-H.;Koo, M.;Gil, J.-M.;Han, K.;Kwon, Y.W.;Song, I.;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Sep 2014, volume: 62, issue:9, pages: 1879 - 1889
Publisher: IEEE
 
» A Fully Levitated Cone-Shaped Lorentz-Type Self-Bearing Machine With Skewed Windings
Abstract:
Brushless dc coreless electric machines with double-rotor and single-stator configuration have very low losses, since the return path of the magnetic flux rotates with the permanent magnets. The eddy-current loss in the stator is additionally very small due to the lack of iron, making it ideal for kinetic energy storage. This paper presents a design for self-bearing rotor suspension, achieved by placing the stator windings skewed on a conical surface. A mathematical analysis of the force from a skewed winding confined to the surface of a cone was found. The parametric analytical expressions of the magnitude and direction of force and torque were verified by finite-element method simulations for one specific geometry. A dynamic model using proportional-integral–differential control was implemented in MATLAB/Simulink, and the currents needed for the self-bearing effect were found by solving an underdetermined system of linear equations. External forces, calculated from acceleration measurements from a bus in urban traffic, were added to simulate the dynamic environment of an electrical vehicle.
Autors: Abrahamsson, J.;Ogren, J.;Hedlund, M.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Sep 2014, volume: 50, issue:9, pages: 1 - 9
Publisher: IEEE
 
» A Fully Parallel LDPC Decoder Architecture Using Probabilistic Min-Sum Algorithm for High-Throughput Applications
Abstract:
This paper presents a normalized probabilistic min-sum algorithm for low-density parity-check (LDPC) codes, where a probabilistic second minimum value, instead of the true second minimum value, is used to facilitate fully parallel decoder realization. The comparators in each check-node unit (CNU) are connected through an interconnect network based on a mix of tree and butterfly networks such that the routing and message passing between the variable-node units (VNUs) and CNUs can be efficiently realized. In order to further reduce the hardware complexity, the normalization operation is realized in the VNU rather than in the CNU. An early termination scheme is proposed in order to prevent unnecessary energy dissipation for both low and high signal-to-noise-ratio regions. The proposed techniques are demonstrated by implementing a (2048, 1723) LDPC decoder using a 90 nm CMOS process. Post-layout simulation results show that the decoder supports a throughput of 45.42 Gbps at 199.6 MHz , achieving the highest throughput and throughput-to-area ratio among comparable works based on a similar or better error performance.
Autors: Cheng, C.-C.;Yang, J.-D.;Lee, H.-C.;Yang, C.-H.;Ueng, Y.-L.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Sep 2014, volume: 61, issue:9, pages: 2738 - 2746
Publisher: IEEE
 
» A Game-Theoretic Analysis of Wind Generation Variability on Electricity Markets
Abstract:
Wind generation variability in an energy-only market such Australian National Electricity Market (NEM) can create significant revenue uncertainties for incumbent generators and substantially increase price risks faced by retailers. This paper presents a Cournot game model to formally analyze how high volatility of wind generation in a concentrated energy-only market can raise the peak/shoulder period (of typically low wind generation) prices to offset the foregone revenue during off-peak periods (of high wind generation). A Monte Carlo simulation around a Cournot game is formulated as an inter-temporal nonlinear optimization problem to assess these issues. The model is implemented for the South Australian zone of the Australian NEM that has experienced high growth in wind generation in recent years. The model results support some of the observed spot pricing behavior in the region in recent years. These findings have significant ramifications for the efficacy of the energy-only market in scenarios with high penetration of intermittent generation.
Autors: Chattopadhyay, D.;Alpcan, T.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Sep 2014, volume: 29, issue:5, pages: 2069 - 2077
Publisher: IEEE
 
» A Game-Theoretic Framework for Robust Optimal Intrusion Detection in Wireless Sensor Networks
Abstract:
A robust optimization model is considered for nonzero-sum discounted stochastic games with incomplete information in order to formally formulate and analyze the intrusion detection problem in wireless sensor networks (WSNs). Security requirements of WSNs are taken into account to characterize the game parameters and model the player objectives. To generalize the problem, the game data are assumed not to be fully known to the players, who take a robust optimization approach to address this data uncertainty. For assessing the validity and effectiveness of the framework, illustrative instances of the developed game model are generated. Equilibrium analysis reveals how the conflicting objectives of the intruder and intrusion detection system compel them to adopt different conservative stances toward data uncertainty. It is also shown, by numerical results, that the robust approach in the presence of uncertainty reduces the sensitivity of the solution with respect to data perturbations, and thus improves design stability.
Autors: Moosavi, H.;Bui, F.M.;
Appeared in: IEEE Transactions on Information Forensics and Security
Publication date: Sep 2014, volume: 9, issue:9, pages: 1367 - 1379
Publisher: IEEE
 
» A General Testability Theory: Classes, Properties, Complexity, and Testing Reductions
Abstract:
In this paper we develop a general framework to reason about testing. The difficulty of testing is assessed in terms of the amount of tests that must be applied to determine whether the system is correct or not. Based on this criterion, five testability classes are presented and related. We also explore conditions that enable and disable finite testability, and their relation to testing hypotheses is studied. We measure how far incomplete test suites are from being complete, which allows us to compare and select better incomplete test suites. The complexity of finding that measure, as well as the complexity of finding minimum complete test suites, is identified. Furthermore, we address the reduction of testing problems to each other, that is, we study how the problem of finding test suites to test systems of some kind can be reduced to the problem of finding test suites for another kind of systems. This enables to export testing methods. In order to illustrate how general notions are applied to specific cases, many typical examples from the formal testing techniques domain are presented.
Autors: Rodriguez, I.;Llana, L.;Rabanal, P.;
Appeared in: IEEE Transactions on Software Engineering
Publication date: Sep 2014, volume: 40, issue:9, pages: 862 - 894
Publisher: IEEE
 
» A Generalized Construction of Extended Goppa Codes
Abstract:
We present a generalized construction of extended length Goppa codes. Using this construction, we obtain 71 new codes in finite field for with better minimum distance than the previously known codes with the same length and dimension.
Autors: Jibril, M.;Bezzateev, S.V.;Tomlinson, M.;Grassl, M.;Ahmed, M.Z.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Sep 2014, volume: 60, issue:9, pages: 5296 - 5303
Publisher: IEEE
 
» A Geometric Framework for Rectangular Shape Detection
Abstract:
Rectangular shape detection has a wide range of applications, such as license plate detection, vehicle detection, and building detection. In this paper, we propose a geometric framework for rectangular shape detection based on the channel-scale space of RGB images. The framework consists of algorithms developed to address three issues of a candidate shape (i.e., a connected component of edge points), including: 1) outliers; 2) open shape; and 3) fragmentation. Furthermore, we propose an interestness measure for rectangular shapes by integrating imbalanced points (one type of interest points). Our experimental study shows the promise of the proposed framework.
Autors: Li, Q.;
Appeared in: IEEE Transactions on Image Processing
Publication date: Sep 2014, volume: 23, issue:9, pages: 4139 - 4149
Publisher: IEEE
 
» A Graph Minor Perspective to Multicast Network Coding
Abstract:
Network coding encourages information coding across a communication network. While the necessity, benefit and complexity of network coding are sensitive to the underlying graph structure of a network, existing theory on network coding often treats the network topology as a black box, focusing on algebraic or information theoretic aspects of the problem. This paper aims at an in-depth examination of the relation between algebraic coding and network topologies. We mathematically establish a series of results along the direction of: if network coding is necessary/beneficial, or if a particular finite field is required for coding, then the network must have a corresponding hidden structure embedded in its underlying topology, and such embedding is computationally efficient to verify. Specifically, we first formulate a meta-conjecture, the NC-minor conjecture, that articulates such a connection between graph theory and network coding, in the language of graph minors. We next prove that the NC-minor conjecture for multicasting two information flows is almost equivalent to the Hadwiger conjecture, which connects graph minors with graph coloring. Such equivalence implies the existence of , , , and minors, for networks that require , , , and to multicast two flows, respectively. We finally pro- e that, for the general case of multicasting arbitrary number of flows, network coding can make a difference from routing only if the network contains a minor, and this minor containment result is tight. Practical implications of the above results are discussed.
Autors: Yin, X.;Wang, Y.;Li, Z.;Wang, X.;Xue, X.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Sep 2014, volume: 60, issue:9, pages: 5375 - 5386
Publisher: IEEE
 
» A Graphene-Enhanced Fiber-Optic Phase Modulator With Large Linear Dynamic Range
Abstract:
We propose a graphene-based modulator integrated into currently used communication fibers. The graphene is directly built into the core of the fiber to ensure the coupling efficiency. The fiber is deliberately side-polished to enhance the light-graphene interaction. The two-dimensional model analysis method and three-dimensional finite difference time domain method are used to rigorously disclose the light modulation mechanism under the anisotropic graphene modeling, which is merely conducted in previous studies. Based on such a structure, a phase modulator with an arm length of 127 is numerically demonstrated with enhanced modulation efficiency. A quasi-linear relation between the phase change and chemical potential of graphene is found theoretically for the first time, providing a large linear dynamic range to control the phase of optical modulation.
Autors: Zhou, F.;Hao, R.;Jin, X.;Zhang, X.;Li, E.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Sep 2014, volume: 26, issue:18, pages: 1867 - 1870
Publisher: IEEE
 
» A Guaranteed Blind and Automatic Probability Density Estimation of Raw Measurements
Abstract:
The use of the histogram to characterize the random component in raw measurements is widely known, applied and applauded. However, its correct use to show the features hidden in the data may require some caution and insight. The most important degree of freedom specified by the user is the binwidth. Although standard rules for binwidth selection exist, they offer no guarantees that the histogram reveals all the desired features. Furthermore, the histogram is a discontinuous representation of the underlying probability density function (pdf) of the data but measured data are usually continuous. Smooth alternatives to the histogram have been developed since the 1970s but still require significant user interaction and insight into the true data probability density. In this paper, we investigate a novel technique that offers a smooth estimate of the pdf without any necessary interaction of the user. The method is fully blind and adaptive such that the best graphical representation of the probability density is ensured.
Autors: Barbe, K.;Gonzales Fuentes, L.;Barford, L.;Lauwers, L.;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Sep 2014, volume: 63, issue:9, pages: 2120 - 2128
Publisher: IEEE
 
» A Harmonic Class-C CMOS VCO-Based on Low Frequency Feedback Loop: Theoretical Analysis and Experimental Results
Abstract:
A novel harmonic Class-C CMOS VCO architecture with improved phase noise performance and power efficiency is presented in this paper. The VCO is based on the widely adopted topology consisting in a crossed pair of NMOS devices refilling a symmetric resonator with a center tapered inductor and biased by a top PMOS current generator. The Class-C operation mode is obtained through a low frequency feedback loop constituted by an operational transconductance amplifier operating the difference between the inductor center tap voltage and a reference voltage, pushing gate polarization voltage of VCO crossed pair devices well below their threshold voltage. The Class-C VCO achieves a theoretical 2.9 dB phase noise improvement compared to the standard differential-pair LC-tank oscillator for the same current consumption. A prototype of the VCO is implemented in a standard RF 55 nm CMOS technology and compared to both a standard and an optimized VCO implemented in the same technology. All these VCOs share a copy of a unique resonator. The Class-C VCO is tunable over the frequency band 6.5–7.8 GHz and displaying an average phase noise lower than 127 dBc/Hz @ 1 MHz offset with a power consumption of 18 mW, for a state-of-the-art figure-of-merit of 187 dBc/Hz @ 1 MHz and 191 dBc/Hz @ 10 MHz offsets, respectively.
Autors: Perticaroli, S.;Dal Toso, S.;Palma, F.;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Sep 2014, volume: 61, issue:9, pages: 2537 - 2549
Publisher: IEEE
 
» A hemispherical Langmuir probe array detector for angular resolved measurements on droplet-based laser-produced plasmas
Abstract:
In this work, a new diagnostic tool for laser-produced plasmas (LPPs) is presented. The detector is based on a multiple array of six motorized Langmuir probes. It allows to measure the dynamics of a LPP in terms of charged particles detection with particular attention to droplet-based LPP sources for EUV lithography. The system design permits to temporally resolve the angular and radial plasma charge distribution and to obtain a hemispherical mapping of the ions and electrons around the droplet plasma. The understanding of these dynamics is fundamental to improve the debris mitigation techniques for droplet-based LPP sources. The device has been developed, built, and employed at the Laboratory for Energy Conversion, ETH Zürich. The experimental results have been obtained on the droplet-based LPP source ALPS II. For the first time, 2D mappings of the ion kinetic energy distribution around the droplet plasma have been obtained with an array of multiple Langmuir probes. These measurements show an anisotropic expansion of the ions in terms of kinetic energy and amount of ion charge around the droplet target. First estimations of the plasma density and electron temperature were also obtained from the analysis of the probe current signals.
Autors: Gambino, Nadia;Brandstatter, Markus;Rollinger, Bob;Abhari, Reza;
Appeared in: Review of Scientific Instruments
Publication date: Sep 2014, volume: 85, issue:9, pages: 093302 - 093302-8
Publisher: IEEE
 
» A high pressure cell for supercritical CO2 on-line chemical reactions studied with x-ray techniques
Abstract:
A versatile high pressure X-ray sample cell has been developed for conducting in situ time-resolved X-ray scattering experiments in the pressure and temperature regime required (pressures up to 210 bars and temperatures up to 120 °C) for chemical reactions in supercritical fluids. The large exit opening angle of the cell allows simultaneous performance of SAXS-WAXS experiments. Diamond windows are used in order to benefit from the combination of maximum strength, minimal X-ray absorption and chemical inertia. The sample cell can also be utilised for X-ray spectroscopy experiments over a wide range of photon energies. Results of the online synthesis of a block copolymer, poly(methyl methacrylate-block-poly(benzyl methacrylate), by Reversible Addition-Fragmentation Chain Transfer (RAFT) in a supercritical CO2 dispersion polymerisation will be discussed. The contribution of the density fluctuations, as function of temperature, to the X-ray scattering signal has been quantified in order to allow appropriate background subtractions.
Autors: Hermida-Merino, Daniel;Portale, Giuseppe;Fields, Peter;Wilson, Richard;Bassett, Simon P.;Jennings, James;Dellar, Martin;Gommes, Cedric;Howdle, Steven M.;Vrolijk, Benno C.M.;Bras, Wim;
Appeared in: Review of Scientific Instruments
Publication date: Sep 2014, volume: 85, issue:9, pages: 093905 - 093905-7
Publisher: IEEE
 
» A high-field magnetic resonance imaging spectrometer using an oven-controlled crystal oscillator as the local oscillator of its radio frequency transceiver
Abstract:
A home-made high-field magnetic resonance imaging (MRI) spectrometer with multiple receiving channels is described. The radio frequency (RF) transceiver of the spectrometer consists of digital intermediate frequency (IF) circuits and corresponding mixing circuits. A direct digital synthesis device is employed to generate the IF pulse; the IF signal from a down-conversion circuit is sampled and followed by digital quadrature detection. Both the IF generation and the IF sampling use a 50 MHz clock. An oven-controlled crystal oscillator, which has outstanding spectral purity and a compact circuit, is used as the local oscillator of the RF transceiver. A digital signal processor works as the pulse programmer of the spectrometer, as a result, 32 control lines can be generated simultaneously while an event is triggered. Field programmable gate array devices are utilized as the auxiliary controllers of the IF generation, IF receiving, and gradient control. High performance, including 1 μs time resolution of the soft pulse, 1 MHz receiving bandwidth, and 1 μs time resolution of the gradient waveform, is achieved. High-quality images on a 1.5 T MRI system using the spectrometer are obtained.
Autors: Liang, Xiao;Tang, Xin;Tang, Weinan;Gao, Jia-Hong;
Appeared in: Review of Scientific Instruments
Publication date: Sep 2014, volume: 85, issue:9, pages: 094705 - 094705-10
Publisher: IEEE
 
» A Highly Efficient Compression Framework for Time-Varying 3-D Facial Expressions
Abstract:
The rapid recent development of 3-DTV technology has led to an increase in studies on mesh-based 3-D scene representation. Compressing 3-D time-varying meshes is critical for the storage and transmission of 3-D contents. This paper proposes a highly efficient framework for compressing time-varying 3-D facial expressions. We use the near-isometric property of human facial expressions to parameterize the 3-D dynamic faces into an expression-invariant 2-D canonical domain that will naturally generate 2-D geometry videos (GVs). Considering the intrinsic properties of GVs, we apply low-rank and sparse matrix decomposition (LRSMD) separately to three dimensions of GVs (namely, and ). Based on our high precision rate and distortion models for GVs, we further compress the components from LRSMD using a video encoder in which bitrates of all components are assigned optimally according to the target bitrate. Experimental results show that the proposed scheme can significantly improve compression performance in terms of rate-distortion performance and visual quality compared with the state-of-the-art algorithms.
Autors: Hou, J.;Chau, L.;Zhang, M.;Magnenat-Thalmann, N.;He, Y.;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Sep 2014, volume: 24, issue:9, pages: 1541 - 1553
Publisher: IEEE
 

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