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Electrical and Electronics Engineering publications abstract of: 02-2012 sorted by title, page: 23
» Security Embedding Codes
Abstract:
This paper considers the problem of simultaneously communicating two messages, a high-security message and a low-security message, to a legitimate receiver, referred to as the security embedding problem. An information-theoretic formulation of the problem is presented. A coding scheme that combines rate splitting, superposition coding, nested binning, and channel prefixing is considered and is shown to achieve the secrecy capacity region of the channel in several scenarios. Specifying these results to both scalar and independent parallel Gaussian channels (under an average individual per-subchannel power constraint), it is shown that the high-security message can be embedded into the low-security message at full rate (as if the low-security message does not exist) without incurring any loss on the overall rate of communication (as if both messages are low-security messages). Extensions to the wiretap channel II setting of Ozarow and Wyner are also considered, where it is shown that “perfect” security embedding can be achieved by an encoder that uses a two-level coset code.
Autors: Ly, H. D.;Liu, T.;Blankenship, Y.;
Appeared in: IEEE Transactions on Information Forensics and Security
Publication date: Feb 2012, volume: 7, issue:1, pages: 148 - 159
Publisher: IEEE
Full litterature document
 
» Security, Privacy, and Policy Roundup
Abstract:
IEEE Security & Privacy news briefs cover the latest in security, privacy, and policy.
Autors: Garber, Lee;
Appeared in: IEEE Security & Privacy
Publication date: Feb 2012, volume: 10, issue:1, pages: 15 - 17
Publisher: IEEE
Full litterature document
 
» Security-constrained unit commitment with wind generation and compressed air energy storage
Abstract:
Wind power is one of the fastest growing renewable sources of generation in the U.S. and many other countries. As wind-generated electricity continues to grow, electric utilities increasingly grapple with the challenges of connecting that power to the grid although maintaining system security. It is difficult to predict and control the output of wind generation because of wind intermittency and a reserve capacity is required to deal with inherent uncertainty. This study presents an approach for security-constrained unit commitment (SCUC) with integration of an energy storage system (ESS) and wind generation. Compressed air energy storage (CAES) is considered as an alternative solution to store energy. For economical operation and control purposes, utilities with CAES are interested in the availability and the dispatch of CAES on an hourly basis, given the specific characteristics of CAES. The main contribution of this study is the development of enhanced SCUC formulation and solution techniques with wind power, CAES and multiple constraints including fuel and emission limit. Proposed approach allows simultaneous optimisation of the energy and the ancillary services (AS). Case studies with eight-bus and 118-bus systems are presented to validate the proposed model. This study also contributes by conducting comprehensive studies to analyse the impact of CAES system on locational pricing, economics, peak-load shaving, transmission congestion management, wind curtailment and environmental perspective.
Autors: Daneshi, H.;Srivastava, A.K.;
Appeared in: IET Generation, Transmission & Distribution
Publication date: Feb 2012, volume: 6, issue:2, pages: 167 - 175
Publisher: IEEE
Full litterature document
 
» Seeing is Believing—Enhancing Message Dissemination in Vehicular Networks Through Visual Cues
Abstract:
One of the stumbling blocks for implementation of Vehicular Ad Hoc Networks is the penetration rate: the percentage of vehicles that have the communication equipment installed. As the equipment deployment is unlikely to happen instantaneously, it is important to explore the performance gains achievable at low penetration rates. This especially pertains to safety applications, which are expected to provide life-saving information to all drivers on the road within a given region. We propose a technique that can be employed by safety applications to address the low penetration issue. By using visual cues on the equipped vehicles, such as specific patterns of hazard warning lights, we show that for all but the lowest vehicle densities, a radio penetration rate of 30% is sufficient to inform more than 95% of drivers in the region of interest in a timely manner.
Autors: Boban, Mate;Vinhoza, Tiago T. V.;Tonguz, Ozan K.;Barros, Joao;
Appeared in: IEEE Communications Letters
Publication date: Feb 2012, volume: 16, issue:2, pages: 238 - 241
Publisher: IEEE
Full litterature document
 
» Segmentation of M-FISH Images for Improved Classification of Chromosomes With an Adaptive Fuzzy C-means Clustering Algorithm
Abstract:
An adaptive fuzzy c-means algorithm was developed and applied to the segmentation and classification of multicolor fluorescence in situ hybridization (M-FISH) images, which can be used to detect chromosomal abnormalities for cancer and genetic disease diagnosis. The algorithm improves the classical fuzzy c-means algorithm (FCM) by the use of a gain field, which models and corrects intensity inhomogeneities caused by a microscope imaging system, flairs of targets (chromosomes), and uneven hybridization of DNA. Other than directly simulating the inhomogeneousely distributed intensities over the image, the gain field regulates centers of each intensity cluster. The algorithm has been tested on an M-FISH database that we have established, which demonstrates improved performance in both segmentation and classification. When compared with other FCM clustering-based algorithms and a recently reported region-based segmentation and classification algorithm, our method gave the lowest segmentation and classification error, which will contribute to improved diagnosis of genetic diseases and cancers.
Autors: Cao, H.;Deng, H.;Wang, Y.-P.;
Appeared in: IEEE Transactions on Fuzzy Systems
Publication date: Feb 2012, volume: 20, issue:1, pages: 1 - 8
Publisher: IEEE
Full litterature document
 
» Segmented-Locally-One-Dimensional-FDTD Method for EM Propagation Inside Large Complex Tunnel Environments
Abstract:
We propose a novel segmented locally one dimensional finite difference time domain (S-LOD-FDTD) method for modeling the electromagnetic wave propagation inside electrically large tunnels. The proposed S-LOD-FDTD method reduces the computational resources by dividing the problem space into segments. To validate this method, we simulate the propagation in real tunnels and compare the results with the published measured data. The comparisons reveal that the proposed method can predict the fields accurately in real, large tunnels at longer ranges with significant savings in execution time and memory.
Autors: Rana, M. M.;Mohan, A. S.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 223 - 226
Publisher: IEEE
Full litterature document
 
» Selecting Key Poses on Manifold for Pairwise Action Recognition
Abstract:
In action recognition, bag of visual words based approaches have been shown to be successful, for which the quality of codebook is critical. In a large vocabulary of poses (visual words), some key poses play a more decisive role than others in the codebook. This paper proposes a novel approach for key poses selection, which models the descriptor space utilizing a manifold learning technique to recover the geometric structure of the descriptors on a lower dimensional manifold. A PageRank-based centrality measure is developed to select key poses according to the recovered geometric structure. In each step, a key pose is selected from the manifold and the remaining model is modified to maximize the discriminative power of selected codebook. With the obtained codebook, each action can be represented with a histogram of the key poses. To solve the ambiguity between some action classes, a pairwise subdivision is executed to select discriminative codebooks for further recognition. Experiments on benchmark datasets showed that our method is able to obtain better performance compared with other state-of-the-art methods.
Autors: Cao, X.;Ning, B.;Yan, P.;Li, X.;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Feb 2012, volume: 8, issue:1, pages: 168 - 177
Publisher: IEEE
Full litterature document
 
» Selective diary of conferences, exhibitions, and courses
Abstract:
Michael Blackman
Autors: Source: World Patent Information, Available online 11 February 2012
Appeared in: Signal Processing
Publication date: Feb 2012
Publisher: Elsevier B.V.
Full litterature document
 
» Self-aligned lateral dual-gate suspended-body single-walled carbon nanotube field-effect transistors
Abstract:
Self-aligned lateral dual-gate suspended-body single-walled carbon nanotube (CNT) field-effect transistors (CNFETs) have been demonstrated. A nano-precision assembly method using resist-assisted ac-dielectrophoresis is applied. Superior I-V characteristics controlled by two independent lateral gates spaced sub-100 nm away from the CNT body are experimentally observed and studied. The dual-gate operation mode effectively boosts the device performance: 34% smaller subthreshold slope, three times larger on-current, and four times higher transconductance. The proposed dual-gate suspended-body CNFETs hold promise for bottom-up fabrication of advanced complementary metal-oxide-semiconductor circuits and nano-electro-mechanical systems devices, such as tunable/switchable resonators for sensing and radio-frequency applications.
Autors: Cao, Ji;Ionescu, Adrian M.;
Appeared in: Applied Physics Letters
Publication date: Feb 2012, volume: 100, issue:6, pages: 063103 - 063103-3
Publisher: IEEE
Full litterature document
 
» Self-Assembly and Self-Tiling: Integrating Active Dies Across Length Scales on Flexible Substrates
Abstract:
This paper reports on recent progress in the field of directed self-assembly, wherein discrete inorganic semiconductor device components are assembled on flexible substrates, and compares these results with prior work. The research aims to develop self-assembly-based chiplet assembly processes that can extend minimal die sizes and throughput beyond what is currently possible with robotic pick and place methods. This manuscript concentrates on self-assembly that is driven by the reduction of surface free energy between liquid solder-coated areas on a substrate and metal-coated contacts on semiconductor dies that act as binding sites. Scaling prior results to sub-100 micrometer-sized components has required a transition to a new self-assembly platform. Specifically, recent work has moved from a drum delivery concept to a new scheme that uses a stepwise reduction of interfacial free energy at a triple interface between oil, water, and a penetrating solder-patterned substrate to introduce components. Finally, this paper also discusses design rules to produce highly periodic “self-tiled” domains on rigid, flexible, and curved substrates. We describe discrete, self-tiled, and microconcentrator-augmented solar cell modules as applications that are fault tolerant and reduce the amount of Si material used by up to a factor of 22 when compared to conventional cells. [2011-0143]
Autors: Knuesel, R. J.;Park, S.;Zheng, W.;Jacobs, H. O.;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Feb 2012, volume: 21, issue:1, pages: 85 - 99
Publisher: IEEE
Full litterature document
 
» Self-assembly takes shape
Abstract:
Researchers exploit new ways to make IC s pull themselves together.
Autors: Courtland, R.;
Appeared in: IEEE Spectrum
Publication date: Feb 2012, volume: 49, issue:2, pages: 14 - 16
Publisher: IEEE
Full litterature document
 
» Self-Protection in a Clustered Distributed System
Abstract:
Self-protection refers to the ability for a system to detect illegal behaviors and to fight-back intrusions with counter-measures. This article presents the design, the implementation, and the evaluation of a self-protected system which targets clustered distributed applications. Our approach is based on the structural knowledge of the cluster and of the distributed applications. This knowledge allows to detect known and unknown attacks if an illegal communication channel is used. The current prototype is a self-protected JEE infrastructure (Java 2 Enterprise Edition) with firewall-based intrusion detection. Our prototype induces low-performance penalty for applications.
Autors: De Palma, N.;Hagimont, D.;Boyer, F.;Broto, L.;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Feb 2012, volume: 23, issue:2, pages: 330 - 336
Publisher: IEEE
Full litterature document
 
» Self-Supported Cooperative Networking for Emergency Services in Multi-Hop Wireless Networks
Abstract:
One of the challenging issues for supporting emergency services in wireless networks is coordinating the network under emergent situations. Cooperative communication (CC) is a promising approach which can offer significant enhancements in multi-hop wireless networks. This paper investigates the potential issues in using this communication paradigm to support emergency services. We focus on promoting energy-efficient and congestion-aware cooperative networking for emergency services based on the idea of Do-It-Yourself. We propose a novel cross-layer design which jointly considers the problems of route selection in network layer, congestion and non-cooperation avoidance among multiple links in MAC layer under cooperative multi-hop wireless environments. We formulate the multi-hop cooperative flow routing and relay node selection process as an optimization problem. Based on the formulations and models, we propose a self-supported networking scheme including three novel components that make the solution procedure highly efficient. Analysis and simulation results show that our approaches significantly achieve better network performance and typically satisfy the requirements for emergency services in multi-hop wireless networks.
Autors: Han, Biao;Li, Jie;Su, Jinshu;Cao, Jiannong;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Feb 2012, volume: 30, issue:2, pages: 450 - 457
Publisher: IEEE
Full litterature document
 
» Semantic Model Vectors for Complex Video Event Recognition
Abstract:
We propose semantic model vectors, an intermediate level semantic representation, as a basis for modeling and detecting complex events in unconstrained real-world videos, such as those from YouTube. The semantic model vectors are extracted using a set of discriminative semantic classifiers, each being an ensemble of SVM models trained from thousands of labeled web images, for a total of 280 generic concepts. Our study reveals that the proposed semantic model vectors representation outperforms—and is complementary to—other low-level visual descriptors for video event modeling. We hence present an end-to-end video event detection system, which combines semantic model vectors with other static or dynamic visual descriptors, extracted at the frame, segment, or full clip level. We perform a comprehensive empirical study on the 2010 TRECVID Multimedia Event Detection task (http://www.nist.gov/itl/iad/mig/med10.cfm), which validates the semantic model vectors representation not only as the best individual descriptor, outperforming state-of-the-art global and local static features as well as spatio-temporal HOG and HOF descriptors, but also as the most compact. We also study early and late feature fusion across the various approaches, leading to a 15% performance boost and an overall system performance of 0.46 mean average precision. In order to promote further research in this direction, we made our semantic model vectors for the TRECVID MED 2010 set publicly available for the community to use (http://www1.cs.columbia.edu/~mmerler/SMV.html).
Autors: Merler, M.;Huang, B.;Xie, L.;Hua, G.;Natsev, A.;
Appeared in: IEEE Transactions on Multimedia
Publication date: Feb 2012, volume: 14, issue:1, pages: 88 - 101
Publisher: IEEE
Full litterature document
 
» Semantic-Aware Metadata Organization Paradigm in Next-Generation File Systems
Abstract:
Existing data storage systems based on the hierarchical directory-tree organization do not meet the scalability and functionality requirements for exponentially growing data sets and increasingly complex metadata queries in large-scale, Exabyte-level file systems with billions of files. This paper proposes a novel decentralized semantic-aware metadata organization, called SmartStore, which exploits semantics of files' metadata to judiciously aggregate correlated files into semantic-aware groups by using information retrieval tools. The key idea of SmartStore is to limit the search scope of a complex metadata query to a single or a minimal number of semantically correlated groups and avoid or alleviate brute-force search in the entire system. The decentralized design of SmartStore can improve system scalability and reduce query latency for complex queries (including range and top-k queries). Moreover, it is also conducive to constructing semantic-aware caching, and conventional filename-based point query. We have implemented a prototype of SmartStore and extensive experiments based on real-world traces show that SmartStore significantly improves system scalability and reduces query latency over database approaches. To the best of our knowledge, this is the first study on the implementation of complex queries in large-scale file systems.
Autors: Yu Hua;Hong Jiang;Yifeng Zhu;Dan Feng;Lei Tian;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Feb 2012, volume: 23, issue:2, pages: 337 - 344
Publisher: IEEE
Full litterature document
 
» Semi-global stabilization of linear time-delay systems with control energy constraint
Abstract:
This note is concerned with the problem of semi-globally stabilizing a linear system with an input delay and a constraint on the energy of its input. Under the condition of null controllability with vanishing energy, the parametric Lyapunov equation basedlow gain feedback is adopted to solve the problem. The proposed approach is applied to the linearized model of the relative motion in the orbit plane of a spacecraft with respect to another spacecraft in a circular orbit around the Earth to validate its effectiveness.
Autors: Bin Zhou, Zongli Lin, James Lam
Appeared in: Automatica
Publication date: Feb 2012
Publisher: Elsevier B.V.
Full litterature document
 
» Sending Learning Pills to Mobile Devices in Class to Enhance Student Performance and Motivation in Network Services Configuration Courses
Abstract:
Teaching electrical and computer software engineers how to configure network services normally requires the detailed presentation of many configuration commands and their numerous parameters. Students tend to find it difficult to maintain acceptable levels of motivation. In many cases, this results in their not attending classes and not dedicating enough time to acquire the required competencies. This paper describes a successful experiment that was able to improve student class attendance, performance, and motivational patterns by using mobile devices in class to provide students with contextualized learning pills. A learning pill is a simple exercise that summarizes some of the key concepts explained in class and promotes reflection and self-study. Each student attending a particular lecture or laboratory session automatically receives a learning pill on his or her mobile phone just after the related concept has been presented. This paper details the scenario used in the experiment and analyzes the performance and motivational patterns of 170 students at the Higher Polytechnic School, Carlos III University of Madrid, Leganes, Spain.
Autors: Munoz-Organero, M.;Munoz-Merino, P. J.;Kloos, C. D.;
Appeared in: IEEE Transactions on Education
Publication date: Feb 2012, volume: 55, issue:1, pages: 83 - 87
Publisher: IEEE
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» Sensorless control of induction motors using multi-level converters
Abstract:
This study describes a sensorless speed control scheme for induction motors supplied by a multi-level inverter. The scheme exploits the low DC link voltage used in some of the multi-level converter configurations which employ H-Bridges. The rotor position is tracked by measuring the rate of change of motor stator currents when low-voltage test vectors are applied using the H-Bridges. In this way, the motor current distortion introduced by the sensorless control scheme is reduced compared to that seen when using a two-level converter. The proposed approach could therefore be applied to high-power motor drives, and automotive drive systems. The study presents a theoretical derivation of the algorithm and experimental results which show the improvement in the motor current quality achieved using the new technique compared to sensorless techniques implemented on a two-level inverter.
Autors: Kamel, S.;Mark, S.;Greg, A.;
Appeared in: IET Power Electronics
Publication date: Feb 2012, volume: 5, issue:2, pages: 269 - 279
Publisher: IEEE
Full litterature document
 
» Sensorless micro-permanent magnet synchronous motor control system with a wide adjustable speed range
Abstract:
This study proposes a new sensorless speed control system for a micro-permanent magnet synchronous motor. Owing to the special characteristics of the micro-permanent magnet synchronous motor, a new rotor position estimator is proposed here. First, by detecting the three-phase zero-current crossing points, a low-resolution of the current position can be detected. Next, by using a Proportional Integral (PI) state estimator, the resolution of the current position can be obviously improved. After that, the deviation voltage between the ideal d-axis voltage and the estimated d-axis voltage is computed to compensate the estimated rotor position. By using the estimated rotor position, the proposed sensorless closed-loop control system, which has good performance including fast transient responses, good load disturbance responses and good tracking responses, can be realised. A digital signal processor, TMS320F28335, is used as a control centre to execute the rotor position estimating algorithm and control algorithm. Experimental results show that the sensorless micro-permanent magnet synchronous motor control system can provide a wide adjustable speed range from 5 to 40 000 r/min with satisfactory performance, which is better than the micro-permanent magnet synchronous motor using an attached 64 pulses/revolution encoder.
Autors: Chou, T.-Y.;Liu, T.-H.;Cheng, T.-T.;
Appeared in: IET Electric Power Applications
Publication date: Feb 2012, volume: 6, issue:2, pages: 62 - 72
Publisher: IEEE
Full litterature document
 
» Sequential Detection With Mutual Information Stopping Cost
Abstract:
This paper formulates and solves a sequential detection problem that involves the mutual information (stochastic observability) of a Gaussian process observed in noise with missing measurements. The main result is that the optimal decision is characterized by a monotone policy on the partially ordered set of positive definite covariance matrices. This monotone structure implies that numerically efficient algorithms can be designed to estimate and implement monotone parametrized decision policies. The sequential detection problem is motivated by applications in radar scheduling where the aim is to maintain the mutual information of all targets within a specified bound. We illustrate the problem formulation and performance of monotone parametrized policies via numerical examples in fly-by and persistent-surveillance applications involving a ground moving target indicator (GMTI) radar.
Autors: Krishnamurthy, V.;Bitmead, R. R.;Gevers, M.;Miehling, E.;
Appeared in: IEEE Transactions on Signal Processing
Publication date: Feb 2012, volume: 60, issue:2, pages: 700 - 714
Publisher: IEEE
Full litterature document
 
» Sequential Subspace Optimization Method for Electromagnetic Devices Design With Orthogonal Design Technique
Abstract:
We present two new sequential optimization strategies, a sequential subspace optimization method (SSOM) and an improved sequential optimization method (SOM) with orthogonal experimental design technique, to deal with optimization design problems of electromagnetic devices in this work. To implement the proposed methods, we first divide the whole design factors into three sets, namely highly-significant, significant, and nonsignificant factors. Then the whole design space can be correspondingly divided into three subspaces with these three sets of factors. Thereafter, SSOM is presented to sequentially optimize those subspaces. In the subspace, we present an improved SOM based on orthogonal experimental design technique to get optimal solutions. Finally, by investigating TEAM benchmark problem 22, we can see that the sampling efficiency can be improved significantly and the computational cost of finite element analysis can be saved remarkably by the proposed methods.
Autors: Lei, G.;Guo, Y. G.;Zhu, J. G.;Chen, X. M.;Xu, W.;Shao, K. R.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 479 - 482
Publisher: IEEE
Full litterature document
 
» Seri Rama: Converting a Shadow Play Puppet to Street Fighter
Abstract:
Shadow puppet plays, a traditional Malaysian theater art, is slowly losing its appeal to adolescents, who prefer computer games. To help reverse this decline, the authors incorporated the traditional Seri Rama character into the Street Fighter video game. Using modeling, texturing, and animation, they developed a 3D Seri Rama prototype. Users can control Seri Rama with a PlayStation game controller.
Autors: Ghani, D.B.A.;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Feb 2012, volume: 32, issue:1, pages: 8 - 11
Publisher: IEEE
Full litterature document
 
» Service identification guideline for developing distributed embedded real-time systems
Abstract:
Analysis and design are the key phases in any software development life cycle. Service identification is one of the most important steps performed in the analysis phase of service-oriented software development life cycle. Service-orientation has been applied successfully in the domain of distributed embedded real-time system because of the advantages it provides such as reusability and interoperability. However, a systematic service-oriented development methodology for distributed embedded real-time system is still missing. A step-by-step guideline for service identification is presented in this study as part of an attempt to define the analysis phase of service-oriented software development life cycle for distributed embedded real-time system. The Smart Home case study is applied to verify the guidelines. This study provides profound descriptions on how to identify services for distributed embedded real-time system. Moreover, this work can be used as a first step towards a systematic service-oriented software development life cycle for distributed embedded real-time systems.
Autors: Mohamad, R.;Aziz, M.W.;Jawawi, D.N.A.;Ghazali, M.;Arbaie, M.Z.;Ibrahim, N.;
Appeared in: IET Software
Publication date: Feb 2012, volume: 6, issue:1, pages: 74 - 82
Publisher: IEEE
Full litterature document
 
» Service Velocity: Rapid Provisioning Strategies in Optical ROADM Networks
Abstract:
The advent of reconfigurable optical add/drop multiplexers with colorless and non-directional add/drop ports enables transponders and regenerators to be pre-deployed, without a priori knowledge of which wavelength or direction they will eventually serve. We study pre-deployment of optical regenerators as a means to drastically reduce the provisioning time, using Monte Carlo simulation of an optical backbone network. With appropriate placement strategies, regenerators can be efficiently pre-deployed so that new connections can be established rapidly, without the delays caused by service visits to intermediate network nodes.
Autors: Woodward, S.;Feuer, M.;Kim, I.;Palacharla, P.;Wang, X.;Bihon, D.;
Appeared in: IEEE/OSA Journal of Optical Communications and Networking
Publication date: Feb 2012, volume: 4, issue:2, pages: 92 - 98
Publisher: IEEE
Full litterature document
 
» SESAMs for High-Power Oscillators: Design Guidelines and Damage Thresholds
Abstract:
We present for the first time to the best of our knowledge a systematic study of lifetime and damage of semiconductor saturable absorber mirrors (SESAMs) designed for operation in high-power oscillators. We characterize and compare nonlinear reflectivity and inverse saturable absorption (ISA) parameters as well as damage threshold and lifetime of different representative SESAMs under test using a nonlinear reflectivity measurement setup at unprecedented high fluence levels. We investigate the catastrophic damage that occurs at very high fluences by demonstrating a dependence of the damage threshold on the ISA parameter F and the maximum reflectivity fluence F . We can clearly demonstrate that the damage fluence F scales proportionally to for all SESAMs. In the case of SESAMs with the same absorber where the product F ·ΔR is constant, the damage fluence F scales proportionally to F . Therefore, damage occurs due to heating of the lattice by the energy absorbed due to the ISA process and is not related to the quantum well (QW) absorbers. Furthermore, we present guidelines on how to design samples with high saturation fluences, reduced induced absorption, and high damage thresholds. Using multiple QWs and a suitable dielectric topsection, we achieved SESAMs with saturation fluences >200 μJ/cm , nonsaturable losses <0.1%, and reduced ISA. Our best sam- le could not be damaged at a maximum available fluence of 0.21 J/cm and a peak intensity of 370 GW/cm . These SESAMs will be suitable for future high-power femtosecond oscillators in the kilowatt average output power regime, which is very interesting for attosecond science and industrial material processing applications.
Autors: Saraceno, C. J.;Schriber, C.;Mangold, M.;Hoffmann, M.;Heckl, O. H.;Baer, C. R.;Golling, M.;Südmeyer, T.;Keller, U.;
Appeared in: IEEE Journal of Selected Topics in Quantum Electronics
Publication date: Feb 2012, volume: 18, issue:1, pages: 29 - 41
Publisher: IEEE
Full litterature document
 
» Set-Membership Error-in-Variables Identification Through Convex Relaxation Techniques
Abstract:
In this technical note, the set membership error-in-variables identification problem is considered, that is the identification of linear dynamic systems when both output and input measurements are corrupted by bounded noise. A new approach for the computation of parameter uncertainty intervals is presented. First, the identification problem is formulated in terms of nonconvex optimization. Then, relaxation techniques based on linear matrix inequalities are employed to evaluate parameter bounds by means of convex optimization. The inherent structured sparsity of the original identification problems is exploited to reduce the computational complexity of the relaxed problems. Finally, convergence properties and complexity of the proposed procedure are discussed. Advantages of the presented technique with respect to previously published results are discussed and shown by means of two simulated examples.
Autors: Cerone, V.;Piga, D.;Regruto, D.;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Feb 2012, volume: 57, issue:2, pages: 517 - 522
Publisher: IEEE
Full litterature document
 
» Setting Adaptive Spike Detection Threshold for Smoothed TEO Based on Robust Statistics Theory
Abstract:
We propose a novel approach aimed at adaptively setting the threshold of the smoothed Teager energy operator (STEO) detector to be used in extracellular recording of neural signals. In this proposed approach, to set the adaptive threshold of the STEO detector, we derive the relationship between the low-order statistics of its input signal and the ones of its output signal. This relationship is determined with only the background noise component assumed to be present at the input. Robust statistics theory techniques were used to achieve an unbiased estimation of these low-order statistics of the background noise component directly from the neural input signal. In this paper, the emphasis is made on extracellular neural recordings. However, the proposed method can be used in the analysis of different biomedical signals where spikes are important for diagnostic (e.g., ECG, EEG, etc.). We validated the efficacy of the proposed method using synthetic neural signals constructed from real neural recordings signals. Four different sets of extracellular recordings from four distinct neural sources have been exploited to that purpose. The first dataset is recorded from an adult male monkey using the Utath 10×10 microelectrode array implemented in the prefrontal cortex, the second one was obtained from the visual cortex of a rat using a stainless-steel-tipped microelectrode, the third dataset came from recording in a human medial lobe using intracranial electrode, and finally, the fourth one was extracted from recordings in a macaque parietal cortex using a single tetrode. Simulation results show that our approach is effective and robust, and outperforms state-of-the-art adaptive detection methods in its category (i.e., efficient and simple, and do not require a priori knowledge about neural spike waveforms shapes).
Autors: Semmaoui, H.;Drolet, J.;Lakhssassi, A.;Sawan, M.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Feb 2012, volume: 59, issue:2, pages: 474 - 482
Publisher: IEEE
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» SEU Tolerant Latch Based on Error Detection
Abstract:
This paper presents an SEU hardened latch that can mitigate SEU based on an error detection circuit and a multiplexer. During the hold phase, an SEU on an internal node may upset the logic state of the latch. But the error detection circuit can detect this fault and generate fault indication signals via precharge and discharge operations. The fault indication signals control a multiplexer to select a correct output. Therefore, each latch has some error detection and correction capability.
Autors: She, X.;Li, N.;Tong, J.;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Feb 2012, volume: 59, issue:1, pages: 211 - 214
Publisher: IEEE
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» SEU Tolerant Memory Using Error Correction Code
Abstract:
With decreasing circuit lithography dimensions and increasing memory densities, an SEU may affect multiple adjacent memory cells. This paper presents an SEU hardened memory using error correction code that can correct single errors, double-adjacent errors, triple-adjacent errors and double-almost-adjacent errors. The proposed memory introduces small area, power and delay overheads.
Autors: She, X.;Li, N.;Jensen, D. W.;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Feb 2012, volume: 59, issue:1, pages: 205 - 210
Publisher: IEEE
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» Shape Optimization of Multistage Depressed Collectors by Parallel Evolutionary Algorithm
Abstract:
In this paper a novel parallel meta-heuristic algorithm called MeTEO is presented, applied to the shape optimization of multistage depressed collectors, simulated by means of a Finite Element collector and electron gun simulator, COLLGUN, which uses the Constructive Solid Geometry for the description of the device shape. METEO is a hybrid algorithm composed by three different heuristics: FSO (Flock of Starlings Optimization), PSO (Particle Swarm Optimization), and BCA (Bacterial Chemotaxis Algorithm); it performs the optimization using both the topological and the metric rules and offers a natural parallel implementation that allows speeding up the whole process of optimization by the fitness modification (FM).
Autors: Coco, S.;Laudani, A.;Pulcini, G.;Riganti Fulginei, F.;Salvini, A.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 435 - 438
Publisher: IEEE
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» Shear-band arrest and stress overshoots during inhomogeneous flow in a metallic glass
Abstract:
At the transition from a static to a dynamic deformation regime of a shear band in bulk metallic glasses, stress transients in terms of overshoots are observed. We interpret this phenomenon with a repeated shear-melting transition and are able to access a characteristic time for a liquidlike to solidlike transition in the shear band as a function of temperature, enabling us to understand why shear bands arrest during inhomogenous serrated flow in bulk metallic glasses.
Autors: MaaB, R.;Klaumunzer, D.;Villard, G.;Derlet, P. M.;Loffler, J. F.;
Appeared in: Applied Physics Letters
Publication date: Feb 2012, volume: 100, issue:7, pages: 071904 - 071904-4
Publisher: IEEE
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» Sheath structure in negative ion sources for fusion (invited)
Abstract:
In fusion negative ion sources, the negative ions are formed on the caesiated plasma grid predominantly by hydrogen atoms from the plasma. The space charge of the negative ions leaving the wall is not fully compensated by incoming positive ions and at high enough emission a virtual cathode is formed. This virtual cathode limits the flux of negative ions transported across the sheath to the plasma. A 1D collisionless model of the sheath is presented taking into account the virtual cathode. The model will be applied to examples of the ion source operation. Extension of the model to the bulk plasma shows good agreement with experimental data. A possible role for fast ions is discussed.
Autors: McAdams, R.;King, D. B.;Holmes, A. J. T.;Surrey, E.;
Appeared in: Review of Scientific Instruments
Publication date: Feb 2012, volume: 83, issue:2, pages: 02B109 - 02B109-5
Publisher: IEEE
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» Short-term electricity prices forecasting in a competitive market by a hybrid PSO-ANFIS approach
Abstract:

Highlights

? A novel hybrid approach is proposed for electricity prices forecasting. ? The proposed approach is based on the combination of PSO and ANFIS. ? A thorough comparison is carried out, taking into account the results of previous publications. ? A good forecasting accuracy is achieved, while a reduced computation time is required.


Autors: In this paper, a novel hybrid approach is proposed for electricity prices forecasting in a competitive market, considering a time horizon of 1 week. The proposed approach is based on the combination of particle swarm optimization and adaptive-network
Appeared in: International Journal of Electrical Power & Energy Systems
Publication date: Feb 2012
Publisher: Elsevier B.V.
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» Short-Term Load Forecasting Based on a Semi-Parametric Additive Model
Abstract:
Short-term load forecasting is an essential instrument in power system planning, operation, and control. Many operating decisions are based on load forecasts, such as dispatch scheduling of generating capacity, reliability analysis, and maintenance planning for the generators. Overestimation of electricity demand will cause a conservative operation, which leads to the start-up of too many units or excessive energy purchase, thereby supplying an unnecessary level of reserve. On the other hand, underestimation may result in a risky operation, with insufficient preparation of spinning reserve, causing the system to operate in a vulnerable region to the disturbance.
Autors: Fan, S.;Hyndman, R. J.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Feb 2012, volume: 27, issue:1, pages: 134 - 141
Publisher: IEEE
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» Short-Term Load Forecasting With Exponentially Weighted Methods
Abstract:
Short-term load forecasts are needed for the efficient management of power systems. Although weather-based modeling is common, univariate models can be useful when the lead time of interest is less than one day. A class of univariate methods that has performed well with intraday data is exponential smoothing. This paper considers five recently developed exponentially weighted methods that have not previously been used for load forecasting. These methods include several exponential smoothing formulations, as well as methods using discount weighted regression, cubic splines, and singular value decomposition (SVD). In addition, this paper presents a new SVD-based exponential smoothing formulation. Using British and French half-hourly load data, these methods are compared for point forecasting up to one day ahead. Although the new SVD-based approach showed some potential, the best performing method was a previously developed exponential smoothing method. A second empirical study showed the better of the univariate methods outperforming a weather-based method up to about five hours ahead, with a combination of these methods producing the best results overall.
Autors: Taylor, J. W.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Feb 2012, volume: 27, issue:1, pages: 458 - 464
Publisher: IEEE
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» Shot-to-shot reproducibility in the emission of fast highly charged metal ions from a laser ion source
Abstract:
The generation of fast highly charged metal ions with the use of the sub-nanosecond Prague Asterix Laser System, operated at a fundamental wavelength of 1315 nm, is reported. Particular attention is paid to shot-to-shot reproducibility in the ion emission. Au and Pd targets were exposed to intensities up to 5 × 1016 W/cm2. Above the laser intensity threshold of ∼3 × 1014 W/cm2 the plasma is generated in a form of irregular bursts. The maximum energy of protons constituting the leading edge of the fastest burst reaches a value up to 1 MeV. The fast ions in the following bursts have energy gradually decreasing with the increasing burst number, namely, from a value of about 0.5 MeV/charge regardless of the atomic number and mass of the ionized species.
Autors: Krasa, J.;Velyhan, A.;Margarone, D.;Krousky, E.;Laska, L.;Jungwirth, K.;Rohlena, K.;Ullschmied, J.;Parys, P.;Ryc, L.;Wołowski, J.;
Appeared in: Review of Scientific Instruments
Publication date: Feb 2012, volume: 83, issue:2, pages: 02B302 - 02B302-3
Publisher: IEEE
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» Sidelobe Suppression with Orthogonal Projection for Multicarrier Systems
Abstract:
Sidelobe suppression, or out-of-band emission reduction, in multicarrier systems is conventionally achieved via time-domain windowing which is spectrum inefficient. Although some sidelobe cancellation and signal predistortion techniques have been proposed for spectrum shaping, tempt{they are generally not well balanced between complexity and suppression performance.} In this paper, an efficient and low-complexity sidelobe suppression with orthogonal projection (SSOP) scheme is proposed. The SSOP scheme uses an orthogonal projection matrix for sidelobe suppression, and adopts as few as one reserved subcarrier for recovering the distorted signal in the receiver. Unlike most known approaches, the SSOP scheme requires multiplications as few as the number of subcarriers in the band, and enables straightforward selection of parameters. Analytical and simulation results show that more than 50dB sidelobe suppression can be readily achieved with only a slight degradation in receiver performance.
Autors: Zhang, Jian Andrew;Huang, Xiaojing;Cantoni, Antonio;Guo, Y. Jay;
Appeared in: IEEE Transactions on Communications
Publication date: Feb 2012, volume: 60, issue:2, pages: 589 - 599
Publisher: IEEE
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» SiGe MEMS at processing temperatures below 250?C
Abstract:
This work demonstrates, for the first time, the use of a post deposition laser annealing technique to realize operational SiGe MEMS devices at deposition temperatures as low as 210?C. The patterned amorphous SiGe layers are treated by an excimer laser to induce crystallization. After the laser treatment, SiGe devices with good electrical and mechanical properties, such as contact resistivity values to a TiN electrode as low as 4.9 × 10 ?cmand a strain gradient of -1.6 × 10 ?m, are obtained. Devices such as an array of functional capacitive test structures and capacitive switches are realized
Autors: Joumana El-Rifai, Sherif Sedky, Rita Van Hoof, Simone Severi, Dennis Lin, ...
Appeared in: Sensors and Actuators A: Physical
Publication date: Feb 2012
Publisher: Elsevier B.V.
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» Sign change in the organic magnetoresistance of tris(8-hydroxyquinolinato)aluminum upon annealing
Abstract:
We report the sign change in the magnetoresistance of a tris(8-hydroxyquinolinato)aluminum film with the morphological change from amorphous to crystalline state upon annealing. The negative component of the magnetoresistance followed power law behavior, whereas the positive one showed non-Lorentzian function behavior. The decreasing absolute values of the negative component with increased annealing temperature may be understood by both intersystem-crossing-based mechanism and quenching of triplet excitons. The increasing values of the positive component with increased annealing temperature may be explained by the increase in the hopping probability of charge carriers with increased crystallinity of the film.
Autors: Kang, Hoju;Lee, Ik-Jae;Sup Yoon, Choon;
Appeared in: Applied Physics Letters
Publication date: Feb 2012, volume: 100, issue:7, pages: 073302 - 073302-4
Publisher: IEEE
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» Signal Pulse Distortion Induced by Stimulated Raman Scattering in High Power Double-Clad Fiber Amplifiers
Abstract:
In this letter, the evolution of the stimulated Raman scattering effect on pulse amplification for an Yb-doped double-clad fiber amplifier is investigated. It is experimentally demonstrated that the generated Raman–Stokes pulses occur together with the signal pulse, which causes severe distortion of the output signal pulse. The signal and Raman spectral components are discriminated and their temporal evolution dependence on peak power is analyzed.
Autors: Melo, M.;Berendt, M. O.;Sousa, J. M.;
Appeared in: IEEE Photonics Technology Letters
Publication date: Feb 2012, volume: 24, issue:4, pages: 252 - 254
Publisher: IEEE
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» Signal Reconstruction via Sampled-Data Control Theory—Beyond the Shannon Paradigm
Abstract:
This paper presents a new method for signal reconstruction by leveraging sampled-data control theory. We formulate the signal reconstruction problem in terms of an analog performance optimization problem using a stable discrete-time filter. The proposed performance criterion naturally takes intersample behavior into account, reflecting the energy distributions of the signal. We present methods for computing optimal solutions which are guaranteed to be stable and causal. Detailed comparisons to alternative methods are provided. We discuss some applications in sound and image reconstruction.
Autors: Yamamoto, Y.;Nagahara, M.;Khargonekar, P. P.;
Appeared in: IEEE Transactions on Signal Processing
Publication date: Feb 2012, volume: 60, issue:2, pages: 613 - 625
Publisher: IEEE
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» Signal Transmission Analysis of Multilayer Graphene Nano-Ribbon (MLGNR) Interconnects
Abstract:
Signal transmission characteristics of some multilayer graphene nano-ribbon (MLGNR) interconnects are studied in this paper, with an equivalent single-conductor (ESC) model implemented for the analysis of their transient responses. In this model, both capacitive and inductive couplings between adjacent GNR layers are treated appropriately. According to the derived transfer function using the fourth-order approximation, the output voltage waveforms are predicted for both 14- and 22-nm technology nodes. In particular, the effects of Fermi level of MLGNR on the time delay of the transmitted rectangular pulse are examined and compared. Based on the decoupled partially differential equations (PDEs) for the common and differential modes of voltage wave propagation in the edge-coupled MLGNR interconnects, their output voltage responses are also predicted for different technology nodes, which are useful for the evaluation of on-chip signal integrity or EMC and EMI issues of MLGNR-built transmission lines for the future ICs.
Autors: Cui, J.-P.;Zhao, W.-S.;Yin, W.-Y.;Hu, J.;
Appeared in: IEEE Transactions on Electromagnetic Compatibility
Publication date: Feb 2012, volume: 54, issue:1, pages: 126 - 132
Publisher: IEEE
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» Silicon CMOS-integrated nano-photonics for computer and data communications beyond 100G
Abstract:
Five criteria that are usually considered by IEEE standards committees for development of next generation standards are broad market potential, distinct identity, and compatibility, as well as technical and economic feasibility. We consider these criteria separately and show that the new emerging large-volume markets loosely defined as Computercom will demand new standards and new technologies. We discuss how the balance between single-channel bit rate, and number of wavelength multiplexed and spatially multiplexed optical channels can help to satisfy the need for huge total bandwidth, while keeping cost low and power efficiency high. Silicon CMOS-integrated photonics holds promise to become a technology of choice for wide deployment of low-power and cost-effective optical interconnects for these new markets, and to become a single solution addressing distances spanning from just a meter to 10km.
Autors: Vlasov, Y.A.;
Appeared in: IEEE Communications Magazine
Publication date: Feb 2012, volume: 50, issue:2, pages: s67 - s72
Publisher: IEEE
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» Silicon-on-Nitride Waveguide With Ultralow Dispersion Over an Octave-Spanning Mid-Infrared Wavelength Range
Abstract:
The proposed silicon-on-nitride (SON) waveguide exhibits an ultrabroadband (4200 nm), low chromatic dispersion in the mid-infrared (MIR) wavelength region from 2430 to 6630 nm. It has two zero-dispersion wavelengths within the span. Even at 6 , the nonlinear coefficients of the SON waveguides are still comparable with the ones of integrated waveguides around 1550 nm, which are widely used for octave-spanning nonlinear process. This enables a potential nonlinear optical platform for broadband signal processing across the over-one-octave MIR bandwidth.
Autors: Yang Yue;Lin Zhang;Hao Huang;Beausoleil, R.G.;Willner, A.E.;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2012, volume: 4, issue:1, pages: 126 - 132
Publisher: IEEE
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» Silver Bullet Talks with Deborah Frincke
Abstract:
Gary McGraw interviews Deborah Frincke, who is currently a member of the Defense Intelligence Senior Executive Service and deputy director for research at the National Security Agency (NSA). This interview was conducted while she served as Chief Scientist of Cybersecurity at the Department of Energy's Pacific Northwest National Laboratory (PNNL). Prior to PNNL, she was a professor at the University of Idaho, where she cofounded the academic Center for Secure and Dependable Systems and also TriGeo Network Security. Frincke is active in the US Department of Energy's cybersecurity grassroots community and an affiliated professor with the University of Washington's iSchool.
Autors: McGraw, Gary;
Appeared in: IEEE Security & Privacy
Publication date: Feb 2012, volume: 10, issue:1, pages: 11 - 14
Publisher: IEEE
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» Simple implementation of vectorial modulo operation based on fundamental parallelepiped
Abstract:
Multidimensional lattices constitute a unifying framework for several signal processing applications. Described is a simple and elegant algorithmic implementation of the vectorial modulo operation based on the lattice fundamental parallelepiped which permits automatising the lattice elements?? indexing.
Autors: Angeletti, P.;
Appeared in: Electronics Letters
Publication date: Feb 2012, volume: 48, issue:3, pages: 159 - 160
Publisher: IEEE
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» Simplified Local Specific Absorption Rate Measurement Method Using Lightweight Phantom Composed of Wave Absorber Embedded of Electric Field Probe
Abstract:
In this paper, a simplified local SAR measurement method is developed. A lightweight phantom composed of wave absorber embedded of electric field probe is designed. The relative permittivity and conductivity of wave absorber is determined in order to equalize the surface electric field of the wave absorber and the standard liquid phantom. For this purpose, it is suitable to equalize the amplitude of the surface impedances of the two cases. The internal electric field is estimated with the estimated penetration depth. The peak spatial-average SAR of an inverted F-antenna mounted on a metal plate using the proposed measurement method is almost identical to the analytical result of the liquid phantom. The error of the proposed measurement method is within the allowable limits including measurement error.
Autors: Michishita, N.;Watanabe, T.;Yamada, Y.;Arai, H.;Tanaka, T.;
Appeared in: IEEE Transactions on Electromagnetic Compatibility
Publication date: Feb 2012, volume: 54, issue:1, pages: 181 - 187
Publisher: IEEE
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» Simulation of Axon Activation by Electrical Stimulation— Applying Alternating-Direction-Implicit Finite- Difference Time-Domain Method
Abstract:
In a typical approach to model electrical stimulation of an axon, a cable model equivalent to an axon was placed in a simple homogeneous medium. An electrode was used to induce an excitation to stimulate the cable model, and then the transmembrane potentials and the ionic currents in the cable model in temporal domain were observed. Unfortunately, this simulation approach is not realistic since inhomogeneous tissues near the axon is not considered. In this paper, the alternating-direction-implicit finite-difference time-domain (ADI-FDTD) method is coupled with the equivalent model of a membrane (the Hodgkin–Huxley model), and a novel simulation scheme is developed to predict axon activation. By testing axon activation with current excitation, the simulation results show the new method is useful for simulating axon activation.
Autors: Choi, C. T. M.;Sun, S.-H.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 639 - 642
Publisher: IEEE
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» Simulation of H- ion source extraction systems for the Spallation Neutron Source with Ion Beam Simulator
Abstract:
A three-dimensional ion optical code IBSimu, which is being developed at the University of Jyväskylä, features positive and negative ion plasma extraction models and self-consistent space charge calculation. The code has been utilized for modeling the existing extraction system of the H- ion source of the Spallation Neutron Source. Simulation results are in good agreement with experimental data. A high-current extraction system with downstream electron dumping at intermediate energy has been designed. According to the simulations it provides lower emittance compared to the baseline system at H- currents exceeding 40 mA. A magnetic low energy beam transport section consisting of two solenoids has been designed to transport the beam from the alternative electrostatic extraction systems to the radio frequency quadrupole.
Autors: Kalvas, T.;Welton, R. F.;Tarvainen, O.;Han, B. X.;Stockli, M. P.;
Appeared in: Review of Scientific Instruments
Publication date: Feb 2012, volume: 83, issue:2, pages: 02A705 - 02A705-3
Publisher: IEEE
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» Simulation of Surface Plasmon Coupled Conjugate Polymer for Polymer Light-Emitting Diodes
Abstract:
Since 1977, conjugated polymers have received attention as materials for display devices with a low-cost solution process, but the low efficiency of these materials has been considered as a drawback which should be overcome. Nowadays metal nanoparticles are inserted on the display device's cathode to overcome the low efficiency of the materials through the enhanced coupling between the Localized surface plasmon resonance (LSPR) and exciton in emitting material . In our previous work, conjugated polymer with an imprinted regular Ag-dot-array structure showed a 2.7-fold improvement of integrated photoluminescence (PL) intensity , but the result was not optimized. Therefore, in this study, we calculated the Ag-dot-array absorbance-peak shift in detail using finite-difference time-domain (FDTD) simulation and found the absorbance peak location which maximized photoluminescence (PL) intensity, depending on various Ag dot condition. The resulting information was applied to the previous structure . Thus, we reduced the trial and error of finding the optimized absorbance peak location and the imprint processing costs. The most important parameter of the Ag-dot-array absorbance peak was the lattice constant. Furthermore, we proved the indium tin oxide (ITO) waveguide effect in our structure using FDTD.
Autors: Yeo, Y. W.;Cho, K. H.;Kim, J. Y.;Choi, K. C.;
Appeared in: Journal of Display Technology
Publication date: Feb 2012, volume: 8, issue:2, pages: 65 - 69
Publisher: IEEE
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» Simulations of ionization in a hot cavity surface ion source
Abstract:
A new numerical Monte Carlo method based model of a hot cavity surface ionization ion source is presented in this paper. The model, intended to support the studies on ionization phenomena in a widely used class of ion sources, takes into account geometry of the ion source and extraction system, ionizer temperature and other features. The results of ion source efficiency calculations for various configurations of the extraction field are reviewed. The dominant role of the ionizer region near the extraction opening is described. Simulated dependences of ionization efficiency on the working parameters like ionizer length and temperature, ionization potential of the substance, and extraction voltage are discussed. A good agreement of the experimental data (e.g., influence of ionizer temperature, current-voltage curve) and the predictions of the model is found. It is also shown that the contribution to the ionization yield from impact of thermionic electrons accelerated by the extraction field may be significant, especially for the substances of small surface ionization coefficient. The simulation results are compared to the predictions of different theoretical models of the ion source—the obtained simulation data are in accordance both with a well-known Kirchner formula and the so called spherical ionizer model.
Autors: Turek, M.;Drozdziel, A.;Pyszniak, K.;Maczka, D.;Słowinski, B.;
Appeared in: Review of Scientific Instruments
Publication date: Feb 2012, volume: 83, issue:2, pages: 023303 - 023303-9
Publisher: IEEE
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» Simulations of the Stent Artifacts in Magnetic Resonance Imaging
Abstract:
This paper presents an approach to simulate the stent artifacts in magnetic resonance imaging (MRI) based on electromagnetic (EM) analysis. The metallic stent disturbs the static magnetic field (B0) and the radiofrequency (RF) field during the MRI procedure, which consequently results in susceptibility artifacts and RF shielding artifacts in MR image. Both the static and RF field distributions with the metallic stent in a uniform imaging phantom are calculated using the commercial finite element method (FEM) software JMAG 10.0. The images with stent artifacts are simulated by an MRI simulator, according to the calculated field distributions. The susceptibility artifacts and RF shielding artifacts are investigated at several conditions respectively. It can be concluded that the stent made of Ni-Ti alloy with a small magnetic susceptibility is promising to obtain the inside information with small susceptibility artifacts, and the stent with the open-cell design causes smaller RF shielding artifacts in MRI than the close-cell design.
Autors: Guo, Y.;Jiang, X.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 659 - 662
Publisher: IEEE
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» Simultaneous measurement of thickness and refractive index by a single-channel self-mixing interferometer
Abstract:
The authors introduce a new method for the simultaneous measurement of thickness d and refractive index n of transparent slabs and thin films. The method is based on the optical phase shift measured by a single-channel, self-mixing interferometer (SMI) as a function of the angle of incidence on the sample. The authors use a motorised rotating stage to apply an angular scan up to ±65° to the sample. Then, the authors analyse the derivative of phase difference with respect to the rotation angle, apply a standardisation and fit it to the theoretical expression and after a few iterations they are able to simultaneously determine n and d, with a typical accuracy of 0.02 and 1%, respectively.
Autors: Fathi, M.T.;Donati, S.;
Appeared in: IET Optoelectronics
Publication date: Feb 2012, volume: 6, issue:1, pages: 7 - 12
Publisher: IEEE
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» Simultaneous Optimization of Droplet Routing and Control-Pin Mapping to Electrodes in Digital Microfluidic Biochips
Abstract:
The number of independent input pins used to control the electrodes in digital microfluidic “biochips” is an important cost-driver in the emerging market place, especially for disposable PCB devices that are being developed for clinical and point-of-care diagnostics. However, most prior work on pin-constrained biochip design considers droplet routing and the assignment of pins to electrodes as independent problems. In this paper, we propose optimization methods to solve the droplet routing and pin-constrained design problems concurrently. First, we formulate the co-optimization problem involving droplet routing and pin-mapping. Next, we present an integer linear programming-based optimization method to solve the droplet-routing and the pin-mapping design problems concurrently. The proposed co-optimization method minimizes the number of control pins. We also present an efficient heuristic approach to tackle the co-optimization problem. These methods overcome a major drawback of a recently proposed method, which leads to infeasible solutions involving conflicts in the mapping of pins to electrodes in different droplet-routing stages. The effectiveness of the proposed co-optimization method is demonstrated for two commercial biochips and an experimental university chip for multiplexed in-vitro diagnostics.
Autors: Zhao, Y.;Chakrabarty, K.;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Feb 2012, volume: 31, issue:2, pages: 242 - 254
Publisher: IEEE
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» Single and Double Edge Cutset Identification in Large Scale Power Networks
Abstract:
Previous work on parameter error identification that is based on calculation of Lagrange multipliers has shown that the errors on single edge cutsets could not be detected and errors on double edge cutsets could not be identified without incorporating phasor measurement units (PMUs). Hence, the first step to address such deficiencies is identification of all single and double edge cutsets for large scale power networks. This paper presents a numerically efficient method which relies on factorization of reduced incidence matrix of the network. Results obtained by implementing the method in IEEE 14-, 30-, and 57-bus test systems and a 4520-bus transmission system are presented to illustrate its computational performance.
Autors: Zhang, L.;Abur, A.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Feb 2012, volume: 27, issue:1, pages: 510 - 516
Publisher: IEEE
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» Single photon emission from InGaN/GaN quantum dots up to 50 K
Abstract:
We have investigated the optical properties of single InGaN quantum dots (QDs) by means of microphotoluminescence (μPL) spectroscopy. The QDs were grown on sapphire substrate using metal organic vapor phase epitaxy. Sharp and isolated single exciton emission lines in the blue spectral range were observed. The QD luminescence shows a strong degree of linear polarization up to 96% perpendicular to the growth axis (c-axis) with no preferential alignment in the xy plane. Second order autocorrelation measurements were performed under pulsed excitation and single photon emission up to 50 K is demonstrated.
Autors: Kremling, Stefan;Tessarek, Christian;Dartsch, Heiko;Figge, Stephan;Hofling, Sven;Worschech, Lukas;Kruse, Carsten;Hommel, Detlef;Forchel, Alfred;
Appeared in: Applied Physics Letters
Publication date: Feb 2012, volume: 100, issue:6, pages: 061115 - 061115-3
Publisher: IEEE
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» Single-Image Refocusing and Defocusing
Abstract:
In this paper, we present a postprocessing method to tackle the single-image refocusing-and-defocusing problem. The proposed method can accomplish the tasks of focus-map estimation and image refocusing and defocusing. Given an image with a mixture of focused and defocused objects, we first detect the edges and then estimate the focus map based on the edge blurriness, which is depicted explicitly by a parametric model. The image refocusing problem is addressed in a blind deconvolution framework, where the image prior is modeled by using both global and local constraints. In particular, we correct the defocused blurry edges to sharp ones with the aid of the parametric edge model and then render this cue as a local prior to ensure the sharpness of the refocused image. Experimental results demonstrate that the proposed method performs well in producing visually plausible images with different focus effects from a single input.
Autors: Zhang, W.;Cham, W.-K.;
Appeared in: IEEE Transactions on Image Processing
Publication date: Feb 2012, volume: 21, issue:2, pages: 873 - 882
Publisher: IEEE
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» Single-Sensor Control Strategies for Semi-Active Steering Damper Control in Two-Wheeled Vehicles
Abstract:
Recent research has led to the design of effective steering control strategies that employ, as controlled variables, the steering velocity and the yaw rate. The yaw rate can be measured by an inertial platform, which is usually already installed on modern motorcycles for advanced traction and braking control systems. Thus, there is an interest in developing effective steering angle estimators to implement single-sensor control strategies without introducing any additional cost for the semi-active steering damper control system. This paper proposes a robust minimum variance linear time-invariant filter and a linear parametrically varying observer to estimate the steering angle based on yaw rate and vehicle speed measurements, the performance of which is compared both via simulation and experimental data. The closed-loop performance of the single-sensor control strategies is finally evaluated and compared with that obtained with the two-sensor algorithm.
Autors: De Filippi, P.;Corno, M.;Tanelli, M.;Savaresi, S. M.;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Feb 2012, volume: 61, issue:2, pages: 813 - 820
Publisher: IEEE
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» Size, morphology and optical properties of SnO2nanoparticles synthesized by facile surfactant-assisted solvothermal processing
Abstract:
Spherical and dumbbell-shaped SnO2nanoparticles were grown by a facile solvothermal using different amounts (0.5, 1 and 1.5 g) of three different surfactants (cetyltrimethylammonium bromide, polyethylene glycol and sodium dodecyl sulfate) in ethylenediamine, serving as both a coordinating and an alkaline reagent. The average particle size, measured by powder X-ray diffraction, was determined to be ~3-6 nm and was confirmed by transmission electron microscopy. The chemical structure of products was studied by Fourier transform infrared spectroscopy. Morphologies and composition of products were characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively. Optical properties of products were investigated by ultraviolet-visible (UV-vis) absorption and photoluminescence spectroscopies. Finally, the formation mechanism of SnO2nanoparticles is discussed.
Autors: V. Rajendran, K. Anandan
Appeared in: Materials Science in Semiconductor Processing
Publication date: Feb 2012
Publisher: Elsevier B.V.
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» Skellam Shrinkage: Wavelet-Based Intensity Estimation for Inhomogeneous Poisson Data
Abstract:
The ubiquity of integrating detectors in imaging and other applications implies that a variety of real-world data are well modeled as Poisson random variables whose means are in turn proportional to an underlying vector-valued signal of interest. In this article, we first show how the so-called Skellam distribution arises from the fact that Haar wavelet and filterbank transform coefficients corresponding to measurements of this type are distributed as sums and differences of Poisson counts. We then provide two main theorems on Skellam shrinkage, one showing the near-optimality of shrinkage in the Bayesian setting and the other providing for unbiased risk estimation in a frequentist context. These results serve to yield new estimators in the Haar transform domain, including an unbiased risk estimate for shrinkage of Haar–Fisz variance-stabilized data, along with accompanying low-complexity algorithms for inference. We conclude with a simulation study demonstrating the efficacy of our Skellam shrinkage estimators both for the standard univariate wavelet test functions as well as a variety of test images taken from the image processing literature, confirming that they offer some performance improvements over existing alternatives.
Autors: Hirakawa, K.;Wolfe, P. J.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Feb 2012, volume: 58, issue:2, pages: 1080 - 1093
Publisher: IEEE
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» Sleep Scheduling for Critical Event Monitoring in Wireless Sensor Networks
Abstract:
In this paper, we focus on critical event monitoring in wireless sensor networks (WSNs), where only a small number of packets need to be transmitted most of the time. When a critical event occurs, an alarm message should be broadcast to the entire network as soon as possible. To prolong the network lifetime, some sleep scheduling methods are always employed in WSNs, resulting in significant broadcasting delay, especially in large scale WSNs. In this paper, we propose a novel sleep scheduling method to reduce the delay of alarm broadcasting from any sensor node in WSNs. Specifically, we design two determined traffic paths for the transmission of alarm message, and level-by-level offset based wake-up pattern according to the paths, respectively. When a critical event occurs, an alarm is quickly transmitted along one of the traffic paths to a center node, and then it is immediately broadcast by the center node along another path without collision. Therefore, two of the big contributions are that the broadcasting delay is independent of the density of nodes and its energy consumption is ultra low. Exactly, the upper bound of the broadcasting delay is only 3D+2L, where D is the maximum hop of nodes to the center node, L is the length of sleeping duty cycle, and the unit is the size of time slot. Extensive simulations are conducted to evaluate these notable performances of the proposed method compared with existing works.
Autors: Peng Guo;Tao Jiang;Qian Zhang;Kui Zhang;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Feb 2012, volume: 23, issue:2, pages: 345 - 352
Publisher: IEEE
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» Slip boundary for fluid flow at rough solid surfaces
Abstract:
A molecular dynamics simulation of slip boundary for fluid flow past a solid surface incorporating roughness effect as characterized by fractal geometry has been conducted with a focus on the origin of slip, fluid structure, and slip boundary flow. The results indicate that interfacial slip develops provided that the wall is effectively uncorrugated. Compared with the atomically smooth surface, extra viscous dissipation is induced for shear flow past a rough surface and leading to a reduction in boundary slip. In particular, we find that a more irregular topography decreases the boundary slip even for the same statistical roughness height.
Autors: Chen, Yongping;Zhang, Chengbin;Shi, Mingheng;Peterson, George P.;
Appeared in: Applied Physics Letters
Publication date: Feb 2012, volume: 100, issue:7, pages: 074102 - 074102-4
Publisher: IEEE
Full litterature document
 
» Small molecules based on bithiazole for solution-processed organic solar cells
Abstract:
image

Highlights

? A series of small molecules based on bithiazole were synthesized. ? These molecules exhibit strong absorption, low HOMO levels and high hole mobilities. ? Solution processed organic solar cells based on these molecules exhibit power conversion efficiencies as high as 2.61%.

Autors:

Graphical abstract

Appeared in: Organic Electronics
Publication date: Feb 2012
Publisher: Elsevier B.V.
Full litterature document
 
» Small Population-Based Particle Swarm Optimization for Short-Term Hydrothermal Scheduling
Abstract:
A small population-based particle swarm optimization (SPPSO) approach is presented to solve the problem of short-term hydrothermal scheduling (STHS). In the proposed approach, a novel mutation operation that selects the flying guides for each individual is employed to enhance the diversity of the small population. A DE algorithm is employed as an acceleration operation to accelerate the convergence of the approach in case that the optimal result has no significant improvements after several iterations. A migration operation is adopted to keep the swarm's crowding diversity above a desired level. In addition, a special repair procedure, instead of the penalty function approach, is applied to handle the complex equality constraints of STHS. The effectiveness of the approach is demonstrated through three hydrothermal test systems published in literature. The results are also compared with those obtained by other evolutionary methods. The fuel cost as well as other performance of the proposed approach has been found to be quite impressive. It is shown that the SPPSO approach can provide a better solution at lesser computational time and effort.
Autors: Zhang, J.;Wang, J.;Yue, C.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Feb 2012, volume: 27, issue:1, pages: 142 - 152
Publisher: IEEE
Full litterature document
 
» Small-Signal Neural Models and Their Applications
Abstract:
This paper introduces the use of the concept of small-signal analysis, commonly used in circuit design, for understanding neural models. We show that neural models, varying in complexity from Hodgkin–Huxley to integrate and fire have similar small-signal models when their corresponding differential equations are close to the same bifurcation with respect to input current. Three applications of small-signal neural models are shown. First, some of the properties of cortical neurons described by Izhikevich are explained intuitively through small-signal analysis. Second, we use small-signal models for deriving parameters for a simple neural model (such as resonate and fire) from a more complicated but biophysically relevant one like Morris–Lecar. We show similarity in the subthreshold behavior of the simple and complicated model when they are close to a Hopf bifurcation and a saddle-node bifurcation. Hence, this is useful to correctly tune simple neural models for large-scale cortical simulations. Finaly, the biasing regime of a silicon ion channel is derived by comparing its small-signal model with a Hodgkin–Huxley-type model.
Autors: Basu, A.;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Feb 2012, volume: 6, issue:1, pages: 64 - 75
Publisher: IEEE
Full litterature document
 
» Small-Size Shielded Metallic Stacked Fabry–Perot Cavity Antennas With Large Bandwidth for Space Applications
Abstract:
New configurations of small-size shielded metallic Fabry–Perot (FP) antennas with improved performance over a large frequency band are presented in -band for space missions. The bandwidth enlargement is obtained by stacking two FP cavities of different size, each of them presenting a low quality factor. Their radiating apertures measure around and 2 , respectively. Concentric corrugations are also introduced between both cavities to control the higher-order modes that are excited systematically in shielded small-size FP antennas due to lateral resonances. The obtained results are compared to those of a single-stage FP cavity antenna with the same aperture size. Several prototypes have been fabricated and measured. An aperture efficiency higher than 70%, a reflection coefficient smaller than 15 dB, and sidelobe levels lower than 20 dB have been obtained experimentally, over a wide frequency band (2.4–2.66 GHz). These characteristics make stacked FP cavity antennas very attractive to replace global coverage horn antennas, or to be used in feed clusters of multiple-beam antennas, especially in - and -bands, where they lead to more compact and less bulky solutions compared to classical feed horns.
Autors: Muhammad, S. A.;Sauleau, R.;Legay, H.;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Feb 2012, volume: 60, issue:2, pages: 792 - 802
Publisher: IEEE
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» Smart Grid & Security [Guest Editoral]
Abstract:
THERE IS A MAJOR GROWTH IN electrical and computer engineering research focused squarely on what has become known as the smart grid. While formal definitions of the smart grid do exist, the concept has grown to include technologies that span virtually all areas of electrical and computer engineering impacting energy sustainability, consumer response, electrification of transportation, and related areas. This is primarily due to the strong dependence on communication, control, and computing capabilities that support new growth in electric power and energy resources and technologies. The emergence of cyberphysical systems broadly captures the essence of this interdependence and has provided a rich theoretical basis for characterizing the challenges associated with maintaining critical assets while optimizing performance.
Autors: Govindarasu, M.;Sauer, P.W.;
Appeared in: IEEE Power and Energy Magazine
Publication date: Feb 2012, volume: 10, issue:1, pages: 16 - 17
Publisher: IEEE
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» Smart Grid, Safe Grid
Abstract:
The existing power delivery system is vulnerable to both natural disasters and intentional attack. A successful terrorist attempt to disrupt the power delivery system could have adverse effects on national security, the economy, and the lives of every citizen. Secure and reliable operation of the electric system is fundamental to national and international economic systems, security, and quality of life.
Autors: Amin, S.M.;Giacomoni, A.M.;
Appeared in: IEEE Power and Energy Magazine
Publication date: Feb 2012, volume: 10, issue:1, pages: 33 - 40
Publisher: IEEE
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» Smith-chart diagnostics for multi-GHz time-domain-reflectometry dielectric spectroscopy
Abstract:
A time-domain-reflectometry Smith-chart display is demonstrated to be a valuable diagnostic tool in a variety of situations in time-domain-reflectometry dielectric spectroscopy. A relative reflection coefficient is formed by dividing the Laplace transform of the reflected sample transient by the Laplace transform of the empty-sensor transient and displaying in the complex plane, with the approximate sensor admittance read from susceptance and conductance circles. The Smith chart provides, as a diagnostic tool, an initial estimate of the dielectric behavior in the multi-GHz range and a means of identifying artifacts in acquisition and Laplace transform, in a way which does not require multiple steps of calibration and is only one step removed from the direct transient. Results are presented for a simple 3.5-mm flat sensor immersed in various liquid media, showing variations in the Smith chart for typical variations in sample permittivity, loss, and conductivity. Results are matched to vector network analyzer (VNA) measurement over an identical frequency range, as well as to finite-element field simulation. Results are also presented for a 3.5-mm sensor with various terminating pin lengths, typically employed at low frequencies and low permittivity media to increase sensor capacitance. For an unshielded pin, the Smith chart detects reflections from sample boundaries and measures the effectiveness of shielding used to eliminate these reflections. For a shielded pin, it characterizes the effect of pin length on the susceptance variation and the onset of pin resonance at high frequencies and high-permittivity values. The effect of artifacts appearing in the Smith chart on the actual calibration is shown by tracking them through the calibration process to the final result. Results are also presented for a 9-mm flat termination used for concrete hydration monitoring, showing effects of transmission-line discontinuities within a terminating plug and the onset of waveguide-- ike modes in a surrounding shield, with results compared to VNA measurement.
Autors: Hager, N. E.;Domszy, R. C.;Tofighi, M. R.;
Appeared in: Review of Scientific Instruments
Publication date: Feb 2012, volume: 83, issue:2, pages: 025108 - 025108-11
Publisher: IEEE
Full litterature document
 
» Smoothed state estimates under abrupt changes using sum-of-norms regularization
Abstract:
The presence of abrupt changes, such as impulsive and load disturbances, commonly occur in applications, but make the state estimation problem considerably more difficult than in the standard setting with Gaussian process disturbance. Abrupt changes often introduce a jump in the state, and the problem is therefore readily and often treated by change detection techniques. In this paper, we take a different approach. The state smoothing problem for linear state space models is here formulated as a constrained least-squares problem with sum-of-norms regularization, a generalization of-regularization. This novel formulation can be seen as a convex relaxation of the well known generalized likelihood ratio method by Willsky and Jones. Another nice property of the suggested formulation is that it only has one tuning parameter, the regularization constant which is used to trade off fit and the number of jumps. Good practical choices of this parameter along with an extension to nonlinear state space models are given.
Autors: Henrik Ohlsson, Fredrik Gustafsson, Lennart Ljung, Stephen Boyd
Appeared in: Automatica
Publication date: Feb 2012
Publisher: Elsevier B.V.
Full litterature document
 
» Society news
Abstract:
Includes: Join us at I2MTC 2012 – The Graduate Student Panel; Women in Instrumentation and Measurement Panel Discussion
Autors: Nechifor, A.;Donnell, K.;
Appeared in: IEEE Instrumentation & Measurement Magazine
Publication date: Feb 2012, volume: 15, issue:1, pages: 62 - 62
Publisher: IEEE
Full litterature document
 
» Soft-Error-Resilient FPGAs Using Built-In 2-D Hamming Product Code
Abstract:
Radiation-induced soft error rate (SER) degrades the reliability of static random access memory (SRAM)-based field programmable gate arrays (FPGAs). This paper presents a new built-in 2-D Hamming product code (2–D HPC) scheme to provide reliable operation of SRAM-based FPGAs in hostile operating environments such as space. Multibit error correction capability of our built-in 2-D HPC can improve the reliability, and hence, system availability, by orders of magnitude. Simulation results show that the large number of error correction capability of 2-D HPC can recover configuration bits without depending on an external memory preserving a golden copy of the configuration bits. To provide efficient 2-D HPC in a built-in logic, we also propose a new 2-D SRAM buffer. Using the proposed multibit error correction scheme, system availability of an SRAM-based FPGA can be more than 99.9999999% with SRAM cell failures in 1 billion h of operation of 7.
Autors: Park, S. P.;Lee, D.;Roy, K.;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Feb 2012, volume: 20, issue:2, pages: 248 - 256
Publisher: IEEE
Full litterature document
 
» Software for the geometric characterisation of insect-proof screens
Abstract:

Highlights

? Screens can prevent or limit the entrance of insects into the greenhouse. ? Novel software has been developed for geometric characterisation of screens. ? The method of analysis is based on digital images taken by microscope or scanner. ? The procedure considers that each hole of the screen represents a quadrilateral. ? The software allows identifying the coordinates of the vertices of the quadrilaterals.


Autors: Novel software has been developed for the geometric characterisation of agrotextiles intended for installation in greenhouse vents as a means of crop protection. This characterisation of insect-proof screens is essential with a view to keeping insect
Appeared in: Computers and Electronics in Agriculture
Publication date: Feb 2012
Publisher: Elsevier B.V.
Full litterature document
 
» Software online bug detection: applying a new kernel method
Abstract:
This study presents a new online bug detection approach for safety critical software systems. The novelty of the proposed approach is the use of support vector machine (SVM) with a customised kernel function to accelerate the detection of bugs early before they could cause the program to fail. The new kernel function is built based on a novel sequencematching technique to measure the similarities between passing and failing executions, represented as sequences of the program predicates. The SVM method constructs a hyperplane that optimally divides the program execution space into two regions of failing and passing executions. The hyperplane could be further applied to detect the symptoms of failure during the program execution. Here the experiments with the Rhythmbox and SPEC2000 test programs, demonstrate the ability of the proposed method in early bug detection with small overhead on the program execution time. Moreover, the proposed approach in this study has revealed 83 out of 132 bugs (i.e. 63%) in Siemens while only 10% of code is required to be manually examined to locate the origins of failure. This is the most promising result compared with the latest approaches to early bug detection.
Autors: Parsa, S.;Naree, S.A.;
Appeared in: IET Software
Publication date: Feb 2012, volume: 6, issue:1, pages: 61 - 73
Publisher: IEEE
Full litterature document
 
» Solid-state source of atomic oxygen for low-temperature oxidation processes: Application to pulsed laser deposition of TiO2:N films
Abstract:
An atomic oxygen (AO) source has been redesigned to coordinate with a pulsed laser deposition system and used to grow nitrogen-doped TiO2 films by deposition of TiN and simultaneous irradiation of the substrate with AO. The AO source uses an incandescently heated thin tube of zirconia as an oxygen permeation media to generate pure AO of low kinetic energy. The emission flux is calibrated using a silver-coated quartz crystal microbalance. The thin shape of the probe and transverse emission geometry of this emission device allow the emission area to be positioned close to the substrate surface, enhancing the irradiation flux at the substrate. AO irradiation is crucial for formation of TiO2 phases via oxidation of the deposited TiN laser plume, and is effective for decrease of the substrate temperature for crystallization of anatase phase to as low as around 200 °C.
Autors: Ojima, Daiki;Chiba, Tetsuya;Shima, Kazunari;Hiramatsu, Hidenori;Hosono, Hideo;Hayashi, Katsuro;
Appeared in: Review of Scientific Instruments
Publication date: Feb 2012, volume: 83, issue:2, pages: 023903 - 023903-5
Publisher: IEEE
Full litterature document
 
» Solution of combined economic and emission dispatch problems of power systems by an opposition-based harmony search algorithm
Abstract:

Highlights

? This paper proposes a novel opposition-based harmony search (OHS) algorithm. ? The OHS algorithm employs opposition-based learning for harmony memory initialization and also for the generation jumping. ? Opposite numbers have been utilized to improve the convergence rate of the harmony search. ? The OHS is employed for four standard combined economic and emission dispatch problems of power systems.


Autors: Evolutionary algorithms (EAs) are well-known optimization approaches to deal with nonlinear and complex problems. However, these population-based algorithms are computationally expensive due to the slow nature of the evolutionary process. Harmony sea
Appeared in: International Journal of Electrical Power & Energy Systems
Publication date: Feb 2012
Publisher: Elsevier B.V.
Full litterature document
 
» Solution of Inverse Problems in Nondestructive Testing by a Kriging-Based Surrogate Model
Abstract:
The inverse problems of electromagnetic nondestructive testing are often solved via the solution of several forward problems. For the latter, precise numerical simulators are available in most of the cases, but the associated computational cost is usually high. Surrogate models (or metamodels)—which are getting more and more widespread in electromagnetics—might be promising alternatives to heavy simulations. Traditionally, such surrogates are used to replace the forward model. However, in this paper the direct use of surrogate models for the solution of inverse problems is studied and illustrated via eddy-current testing examples.
Autors: Bilicz, S.;Lambert, M.;Gyimothy, S.;Pavo, J.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 495 - 498
Publisher: IEEE
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» Solution to Economic Dispatching With Disjoint Feasible Regions Via Semidefinite Programming
Abstract:
This paper presents a semidefinite programming approach for the solution of scheduling problems that have disjoint feasible regions. The approach is based on formulating the problem as a mathematical program with vanishing constraints. The solution is obtained using Shor's semidefinite relaxation scheme combined with a rank constraint which is enforced via convex iteration.
Autors: Jabr, R. A.;
Appeared in: IEEE Transactions on Power Systems
Publication date: Feb 2012, volume: 27, issue:1, pages: 572 - 573
Publisher: IEEE
Full litterature document
 
» Solution-processed low leakage organic field-effect transistors with self-pattern registration based on patterned dielectric barrier
Abstract:
image

Highlights

? Novel architecture of solution-processed organic field-effect transistor (OFET). ? Hydrophobic patterned dielectric barrier with a cavity for active region. ? Reduction of the leakage current by screening out the vertical charge flow. ? Self-pattern registration of soluble organic material by the selective wettability. ? The physical origin of the leakage current in the OFET was systematically analyzed.

Autors:

Graphical abstract

Appeared in: Organic Electronics
Publication date: Feb 2012
Publisher: Elsevier B.V.
Full litterature document
 
» Solution-processed organic crystals for field-effect transistor arrays with smooth semiconductor/dielectric interface on paper substrates
Abstract:
image

Highlights

? Solution-processed organic crystals in well-confined patterns for FET arrays on paper substrate. ? A solution-processed approach for the patterning of paper surface wettability. ? A simple, fast, and direct spin-coating process for the growth of organic crystals. ? High performance with?FETof 1.3 cm/V s and on/off ratio of 10. ? Smooth semiconductor/dielectric interface with low trap density.

Autors:

Graphical abstract

Appeared in: Organic Electronics
Publication date: Feb 2012
Publisher: Elsevier B.V.
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» Some Amendments to “Field-to-Wire Coupling in an Electrically Large Cavity: A Semianalytic Solution”
Abstract:
In this correspondence, we propose a supplementary spatial correlation function used to amend a simplification made in an earlier published paper in which a semianalytic solution of field-to-wire coupling in an electrically large cavity was first proposed. It can be shown that the horizontal and vertical components of the incident field are correlated in most cases. Without neglecting the correlation between the field components, the supplementary function can help to give more accurate results. It is demonstrated by two numerical simulation examples in which the semianalytic results are compared with the Monte Carlo results and/or the analytic solution.
Autors: Zhang, H.;Zhao, X.;Yan, L.;Liu, C.;Huang, K.;
Appeared in: IEEE Transactions on Electromagnetic Compatibility
Publication date: Feb 2012, volume: 54, issue:1, pages: 232 - 234
Publisher: IEEE
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» Some Novel Ideas of Spacecraft Charging Mitigation
Abstract:
The level of spacecraft surface charging is determined by current balance. At geosynchronous altitude, photoelectron currents from spacecraft surfaces exceed the ambient electron currents. Lacking photoemission, however, the dark side of a spacecraft can charge to high negative voltages, which, in turn, affect the sunlit side. This paper explores the feasibility of using the following: 1) mirrors and 2) artificial photon sources, such as xenon excimer lamps or vacuum ultraviolet LEDs, to generate sufficient photoemission from the dark side to prevent high-level negative voltage charging.
Autors: Lai, S. T.;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Feb 2012, volume: 40, issue:2, pages: 402 - 409
Publisher: IEEE
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» Some Relations Between Extended and Unscented Kalman Filters
Abstract:
The unscented Kalman filter (UKF) has become a popular alternative to the extended Kalman filter (EKF) during the last decade. UKF propagates the so called sigma points by function evaluations using the unscented transformation (UT), and this is at first glance very different from the standard EKF algorithm which is based on a linearized model. The claimed advantages with UKF are that it propagates the first two moments of the posterior distribution and that it does not require gradients of the system model. We point out several less known links between EKF and UKF in terms of two conceptually different implementations of the Kalman filter: the standard one based on the discrete Riccati equation, and one based on a formula on conditional expectations that does not involve an explicit Riccati equation. First, it is shown that the sigma point function evaluations can be used in the classical EKF rather than an explicitly linearized model. Second, a less cited version of the EKF based on a second-order Taylor expansion is shown to be quite closely related to UKF. The different algorithms and results are illustrated with examples inspired by core observation models in target tracking and sensor network applications.
Autors: Gustafsson, F.;Hendeby, G.;
Appeared in: IEEE Transactions on Signal Processing
Publication date: Feb 2012, volume: 60, issue:2, pages: 545 - 555
Publisher: IEEE
Full litterature document
 
» Some Treatments of Fictitious Volume Charges in Nonlinear Magnetostatic Analysis by BIE
Abstract:
The scalar potential formulation by the boundary integral equation approach is attractive for numerical analysis but has fatal drawbacks due to a multi-valued function in current excitation. We derive an all-purpose boundary integral equation with double layer charges as the state variable and apply it to nonlinear magnetostatic problems by regarding the nonlinear magnetization as fictitious volume charges. We investigate two approaches how to treat the fictitious charges. In discretization by the constant volume element, a surface loop current is introduced for the volume charge. By the linear volume element, the fictitious charges are evaluated on the condition that the divergence of the magnetic flux density is zero. We give a comparative study of these two approaches.
Autors: Ishibashi, K.;Andjelic, Z.;Takahashi, Y.;Takamatsu, T.;Tsuzaki, K.;Wakao, S.;Fujiwara, K.;Ishihara, Y.;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2012, volume: 48, issue:2, pages: 463 - 466
Publisher: IEEE
Full litterature document
 
» Sound That Matters: Basic Knowledge for Electric Motor Application
Abstract:
The sound emitted from industrial electric motors can adversely affect the comfort and safety of those individuals who work in their vicinity. As such, many customers and governing agencies impose strict sound limitations on motors placed in audibly sensitive applications. This article will explore the nature of sound data and how it is measured and interpreted. Topics will include the decibel, differences between sound power and sound pressure, along with octave bands and various weightings. The equipment and procedures necessary for reliable sound data acquisition will be reviewed. Causes and mitigation methods of sound within electric motors will be discussed. Finally, applicable industry specifications will be compared to give a sample of standards that provide guidance to users in this area.
Autors: Hillhouse, J.;
Appeared in: IEEE Industry Applications Magazine
Publication date: Feb 2012, volume: 18, issue:1, pages: 38 - 45
Publisher: IEEE
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» Source Modeling for Distributed Video Coding
Abstract:
This paper studies source and correlation models for distributed video coding (DVC). It first considers a two-state HMM, i.e., a Gilbert–Elliott process, to model the bit-planes produced by DVC schemes. A statistical analysis shows that this model allows us to accurately capture the memory present in the video bit-planes. The achievable rate bounds are derived for these ergodic sources, first assuming an additive binary symmetric correlation channel between the two sources. These bounds show that a rate gain can be achieved by exploiting the sources memory with the additive BSC model. A Slepian–Wolf decoding algorithm which jointly estimates the sources and the source model parameters is then described. Simulation results show that the additive correlation model does not always fit well with the correlation between the actual video bit-planes. This has led us to consider a second correlation model (the predictive model). The rate bounds are then derived for the predictive correlation model in the case of memory sources, showing that exploiting the source memory does not bring any rate gain and that the noise statistic is a sufficient statistic for the MAP decoder. We also evaluate the rate loss when the correlation model assumed by the decoder is not matched to the true one. An a posteriori estimation of the correlation channel has hence been added to the decoder in order to use the most appropriate correlation model for each bit-plane. The new decoding algorithm has been integrated in a DVC decoder, leading to a rate saving of up to 10.14% for the same PSNR, with respect to the case where the bit-planes are assumed to be memoryless uniform sources correlated with the SI via an additive channel model.
Autors: Toto-Zarasoa, V.;Roumy, A.;Guillemot, C.;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Feb 2012, volume: 22, issue:2, pages: 174 - 187
Publisher: IEEE
Full litterature document
 
» Space Division Multiplexed Transmission of 109-Tb/s Data Signals Using Homogeneous Seven-Core Fiber
Abstract:
We achieved record 109-Tb/s transmission over 16.8 km, using space division multiplexing (SDM) together with conventional multiplexing technology. 7-core SDM, 97 WDM (100-GHz spacing), 2 86 Gb/s PDM-QPSK signals were used. The spectral efficiency was 11.2 b/s/Hz. SDM transmission was realized using a multi-core fiber with ultra-low-crosstalk (less than dB/km at 1550 nm) and high performance SDM MUX/DEMUX. The overall SDM crosstalk of dB caused almost no penalty for the PDM-QPSK transmission.
Autors: Sakaguchi, J.;Awaji, Y.;Wada, N.;Kanno, A.;Kawanishi, T.;Hayashi, T.;Taru, T.;Kobayashi, T.;Watanabe, M.;
Appeared in: Journal of Lightwave Technology
Publication date: Feb 2012, volume: 30, issue:4, pages: 658 - 665
Publisher: IEEE
Full litterature document
 
» Space radiation effects on Future Quantum Satellites
Abstract:
Many disturbances in the electronic systems of satellites are caused by the space radiations. Like other electronic systems, the electronic systems of satellites are subject to improve to nanoelectronic systems. Quantum Cellular Automata represents an emerging technology at the nanotechnology level. The effects of space radiations on quantum binary wire are investigated. Single Electron Fault is a fault which may happen during operation of QCA circuits. A detailed simulation based logic level modeling of Single Electron Fault for QCA binary wire is represented.
Autors: Mojdeh Mahdavi, Mohammad Amin Amiri
Appeared in: Aerospace Science and Technology
Publication date: Feb 2012
Publisher: Elsevier B.V.
Full litterature document
 
» Space-Modulated Junction Termination Extension for Ultrahigh-Voltage p-i-n Diodes in 4H-SiC
Abstract:
An edge termination method, referred to as space-modulated junction termination extension (SMJTE) combined with a mesa structure, is presented for ultrahigh-voltage p-i-n diodes in 4H-SiC. Numerical device simulations have been performed for over 15-kV-class 4H-SiC p-i-n diodes with the proposed edge termination. The structure exhibits a high breakdown capability with an improved tolerance for the deviation of impurity dose in the JTE region. Unlike conventional multi-implantation, the proposed termination technique utilizes a single-step implantation with a single mask. A desired laterally tapered doping profile is achieved by fragmenting a conventional JTE region using relatively wide spaces. The simple process of the proposed edge termination makes it applicable to fabrication of various high-voltage devices in 4H-SiC.
Autors: Feng, G.;Suda, J.;Kimoto, T.;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Feb 2012, volume: 59, issue:2, pages: 414 - 418
Publisher: IEEE
Full litterature document
 
» Spacecraft attitude control via a combined state-dependent Riccati equation and adaptive neuro-fuzzy approach
Abstract:
A hybrid nonlinear controller for spacecraft attitude and rate tracking is presented though a combination of two control techniques. Based on the augmentation of spacecraft dynamics and kinematics, a pseudo-linear formulation is derived and used for the development of the basic controller. The basic controller follows a Modified State-Dependent Riccati Equation MSDRE scheme. A neuro-fuzzy controller is designed using an Adaptive Neuro-Fuzzy Inference System ANFIS utilizing the off-line solutions of the MSDRE. The combined control scheme is applied according to large time intervals of the MSDRE solutions to obtain the optimal control torques while along each time interval the ANFIS controller provides the required control signal. The global asymptotic stability of the MSDRE and MSDRE/ANFIS is investigated using Lyapunov theorem and verified by Monte Carlo simulations. The results show a considerable amount of reduction in the computational burden while the tracking accuracy is dependent on the size of the time interval to update the ANFIS controller.
Autors: Mohammad Abdelrahman, Sang-Young Park
Appeared in: Aerospace Science and Technology
Publication date: Feb 2012
Publisher: Elsevier B.V.
Full litterature document
 
» Spacing-Switchable Multiwavelength Fiber Laser Based on Nonlinear Polarization Rotation and Brillouin Scattering in Photonic Crystal Fiber
Abstract:
A new spacing-switchable multiwavelength erbium-doped fiber laser (EDFL) is demonstrated using switchable nonlinear polarization rotation (NPR) and stimulated Brillouin scattering (SBS) effects. The laser employs a 100-m-long photonic crystal fiber in conjunction with a four-port circulator in a figure-of-eight arrangement to provide the intensity-dependent transmission effect, as well as to discriminate the even-order and odd-order Brillouin Stokes to have a double-frequency Brillouin Stokes output. Without the Brillouin pump (BP), the laser operates in an NPR mode to produce at least 22 lasing wavelengths with a side mode suppression ratio of more than 10 dB and a wavelength spacing of 0.27 nm. In the Brillouin erbium fiber laser mode, at least 30 Brillouin lines with a spacing of 0.16 nm are obtained at BP power of 3 dBm and 980-nm pump power of 120 mW.
Autors: Shahabuddin, N.S.;Ahmad, H.;Yusoff, Z.;Harun, S.W.;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2012, volume: 4, issue:1, pages: 34 - 38
Publisher: IEEE
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» Spain declares war on online pirates [Spectral Lines]
Abstract:
As 2012 began—and less than two months after winning control over the Spanish parliament—the rightleaning Partido Popular passed a controversial new anti-Internet-piracy law that will impose strict penalties on website owners who fail to remove copyrighted material from their sites.
Autors: Peck, M.E.;
Appeared in: IEEE Spectrum
Publication date: Feb 2012, volume: 49, issue:2, pages: 8 - 8
Publisher: IEEE
Full litterature document
 
» Sparse Ensemble Learning for Concept Detection
Abstract:
This work presents a novel sparse ensemble learning scheme for concept detection in videos. The proposed ensemble first exploits a sparse non-negative matrix factorization (NMF) process to represent data instances in parts and partition the data space into localities, and then coordinates the individual classifiers in each locality for final classification. In the sparse NMF, data exemplars are projected to a set of locality bases, in which the non-negative superposition of basis images reconstructs the original exemplars. This additive combination ensures that each locality captures the characteristics of data exemplars in part, thus enabling the local classifiers to hold reasonable diversity in their own regions of expertise. More importantly, the sparse NMF ensures that an exemplar is projected to only a few bases (localities) with non-zero coefficients. The resultant ensemble model is, therefore, sparse, in the way that only a small number of efficient classifiers in the ensemble will fire on a testing sample. Extensive tests on the TRECVid 08 and 09 datasets show that the proposed ensemble learning achieves promising results and outperforms existing approaches. The proposed scheme is feature-independent, and can be applied in many other large scale pattern recognition problems besides visual concept detection.
Autors: Tang, S.;Zheng, Y.-T.;Wang, Y.;Chua, T.-S.;
Appeared in: IEEE Transactions on Multimedia
Publication date: Feb 2012, volume: 14, issue:1, pages: 43 - 54
Publisher: IEEE
Full litterature document
 
» Sparse Estimation of Spectral Lines: Grid Selection Problems and Their Solutions
Abstract:
Grid selection for sparse estimation of spectral-line parameters is a critical problem that was in need of a satisfactory solution: assuming the usual case of a uniform spectral grid how should one select the number of grid points, We first present a simple practical rule for choosing an initial value (or initial values) of in a given situation. Then, we go on to explain how the estimation results corresponding to different values of can be compared with one another and therefore how to select the “best” value of among those considered. Furthermore, we introduce a method for detecting when a grid is “too rough” and for obtaining refined parameter estimates in such a case.
Autors: Stoica, P.;Babu, P.;
Appeared in: IEEE Transactions on Signal Processing
Publication date: Feb 2012, volume: 60, issue:2, pages: 962 - 967
Publisher: IEEE
Full litterature document
 
» Sparse representation and position prior based face hallucination upon classified over-complete dictionaries
Abstract:

Highlights

? It is the first to combine sparse representation with the position prior of human face. ? It is the first to construct many local dictionaries according to the different regions of human face. ? It can produce sharper HR faces with more details and less artifacts compared to the recent methods.


Autors: In compressed sensing theory, decomposing a signal based upon redundant dictionaries is of considerable interest for data representation in signal processing. The signal is approximated by an over-complete dictionary instead of an orthonormal basis f
Appeared in: Signal Processing
Publication date: Feb 2012
Publisher: Elsevier B.V.
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» Sparse Solution of Underdetermined Systems of Linear Equations by Stagewise Orthogonal Matching Pursuit
Abstract:
Finding the sparsest solution to underdetermined systems of linear equations is NP-hard in general. We show here that for systems with “typical”/“random” , a good approximation to the sparsest solution is obtained by applying a fixed number of standard operations from linear algebra. Our proposal, Stagewise Orthogonal Matching Pursuit (StOMP), successively transforms the signal into a negligible residual. Starting with initial residual , at the -th stage it forms the “matched filter” , identifies all coordinates with amplitudes exceeding a specially chosen threshold, solves a least-squares problem using the selected coordinates, and subtracts the least-squares fit, producing a new residual. After a fixed number of stages (e.g., 10), it stops. In contrast to Orthogonal Matching Pursuit (OMP), many coefficients can enter the model at each stage in StOMP while only one enters per stage in OMP; and StOMP takes a fixed number of stages (e.g., 10), while OMP can take many (e.g., ). We give both theoretical and empirical support for the large-system effectiveness of StOMP. We give numerical examples showing that StOMP rapidly and reliably finds sparse solutions in compressed sensing, decoding of error-correcting codes, and overcomplete representation.
Autors: Donoho, D. L.;Tsaig, Y.;Drori, I.;Starck, J.-L.;
Appeared in: IEEE Transactions on Information Theory
Publication date: Feb 2012, volume: 58, issue:2, pages: 1094 - 1121
Publisher: IEEE
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» Sparse-Grid-Based Adaptive Model Predictive Control of HL60 Cellular Differentiation
Abstract:
Quantitative methods such as model-based predictive control are known to facilitate the design of strategies to manipulate biological systems. This study develops a sparse-grid-based adaptive model predictive control (MPC) strategy to direct HL60 cellular differentiation. Sparse-grid sampling and interpolation support a computationally efficient adaptive MPC scheme in which multiple data-consistent regions of the model parameter space are identified and used to calculate a control compromise. The algorithm is evaluated in silico with structural model mismatch. Simulations demonstrate how the multiscenario control strategy more effectively manages the mismatch compared to a single scenario approach. Furthermore, the controller is evaluated in vitro to differentiate HL60 cells in both normal and perturbed environments. The controller-derived input sequence successfully achieves and sustains the specified target level of granulocytes when implemented in the laboratory. The results and analysis given here imply that adoption of this experiment planning technique to direct cell differentiation within more complex tissue engineered constructs will require the use of a reasonably accurate mathematical model and an extension of this algorithm to multiobjective controller design.
Autors: Noble, S. L.;Wendel, L. E.;Donahue, M. M.;Buzzard, G. T.;Rundell, A. E.;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Feb 2012, volume: 59, issue:2, pages: 456 - 463
Publisher: IEEE
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» Spatial distribution of the charged particles and potentials during beam extraction in a negative-ion source
Abstract:
We report on the characteristics of the electronegative plasma in a large-scale hydrogen negative ion (H-) source. The measurement has been made with a time-resolved Langmuir probe installed in the beam extraction region. The H- density is monitored with a cavity ring-down system to identify the electrons in the negative charges. The electron-saturation current decreases rapidly after starting to seed Cs, and ion-ion plasma is observed in the extraction region. The H- density steps down during the beam extraction and the electron density jumps up correspondingly. The time integral of the decreasing H- charge density agrees well with the electron charge collected with the probe. The agreement of the charges is interpreted to indicate that the H- density decreasing at the beam extraction is compensated by the electrons diffusing from the driver region. In the plasmas with very low electron density, the pre-sheath of the extraction field penetrates deeply inside the plasmas. That is because the shielding length in those plasmas is longer than that in the usual electron-ion plasmas, and furthermore the electrons are suppressed to diffuse to the extraction region due to the strong magnetic field.
Autors: Tsumori, K.;Nakano, H.;Kisaki, M.;Ikeda, K.;Nagaoka, K.;Osakabe, M.;Takeiri, Y.;Kaneko, O.;Shibuya, M.;Asano, E.;Kondo, T.;Sato, M.;Komada, S.;Sekiguchi, H.;Kameyama, N.;Fukuyama, T.;Wada, S.;Hatayama, A.;
Appeared in: Review of Scientific Instruments
Publication date: Feb 2012, volume: 83, issue:2, pages: 02B116 - 02B116-5
Publisher: IEEE
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