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作者： Jung, Sung-Chan Negra, Renato Ghannouchi, Fadhel M. Microwave Circuits and Systems Laboratory School of Information and Communication Engineering Sungkyunkwan University Suwon 440-746 Korea Republic of Mixed Signal CMOS Circuits Group RWTH Aachen University Aachen 52056 Germany IRadio Laboratory Electrical and Computer Engineering Department University of Calgary Calgary AB T2N 1N4 Canada

This paper proposes a methodology to design and optimize the footprint of miniaturized 3-dB branch-line hybrid couplers, which consists of high-impedance transmission lines and distributed capacitors. To minimize the physical size of the coupler, the distributed capacitors are placed within the empty space of the hybrid. The proposed design methodology calls for the joint optimization of the length of the reduced high-impedance transmission lines and the area of the distributed capacitors. A prototype at S-band was designed and built to validate the approach. It showed a size reduction by 62% compared with the conventional 3-dB branch-line hybrid coupler while providing similar performance and bandwidth. © 2006 IEEE.

关键词： Electric lines

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A PYRAMID-BASED BLOCK OF SKEWERS FOR PIXEL PURITY INDEX FOR ENDMEMBER EXTRACTION IN HYPERSPECTRAL IMAGERY

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International Journal of High Speed Electronics and Systems 2008年第2期18卷 469-482页

作者： CHEIN-I CHANG MINGKAI HSUEH WEIMIN LIU CHAO-CHENG WU FARZEEN CHAUDHRY GREGORY SOLYAR ANTONIO PLAZA Remote Sensing Signal and Image Processing Laboratory Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore MD 21250 USA Computer Science Department University of Extremadura Avda. de la Universidad s/n 10.071 Caceres Spain

Pixel Purity Index (PPI) has been widely used for endmember extraction. Recently, an approach using blocks of skewers was proposed by Theiler et al., called blocks of skewers (BOS) method, to improve computation of the PPI. It utilizes a block of skewers to reduce number of calculations of dot products operated by the PPI on each skewers with all data sample vectors. Unfortunately, the BOS method also suffers from the same drawbacks that the PPI does in terms of several parameters which are needed to be determined a priori . Besides, it also has an additional parameter, block size, B needed to be determined where no guideline is provided of how to select this parameter. In this paper, the BOS method is also investigated. Most importantly, a new pyramid-based block design for the BOS method is also introduced as opposed to the cube-based block designed used by Theiler et al.'s BOS. One major advantage of our proposed pyramid-based BOS over Theiler et al.'s cube-design BOS is the hardware design for Field Programmable Gate Arrays (FPGAs) implementation.

关键词： Blocks of skewers (BOS) method Field Programmable Gate Arrays (FPGAs) Pixel purity index (PPI)

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Novel DCT-based real-valued discrete Gabor transform

Novel DCT-based real-valued discrete Gabor transform

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： Liang Tao Hon Keung Kwan MOE Key Laboratory of Intelligent Computing & Signal Processing Anhui University Hefei Anhui China Department of Electrical and Computer Engineering University of Windsor Windsor ONT Canada

The traditional DCT-based real-valued discrete Gabor transform (RGDT) was limited to the critical sampling case. The biorthogonality relationship between the analysis window and the synthesis window for the transform has not been unveiled. To overcome those drawbacks, this paper proposes a novel DCT-based real-valued discrete Gabor transform, which can be applied under both the critical sampling condition and the over-sampling condition. And the biorthogonality relationship between the analysis window and the synthesis window for the transform is also proved in this paper. Because it only involves real operations and can utilize fast DCT and DDCT algorithms for fast computation, it facilitates computation and implementation by hardware and/or software compared to the traditional complex-valued discrete Gabor transform.

关键词： Discrete transforms Sampling methods Hardware Discrete cosine transforms Software algorithms Biomedical signal processing signal sampling signal synthesis signal processing algorithms Parallel algorithms

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User-guided interictal spike detection

User-guided interictal spike detection

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： Mahmoud El-Gohary James McNames Siegward Elsas Biomedical Signal Processing Laboratory Portland State University Portland OR USA Biomedical Signal Processing Laboratory Department of Electrical and Computer Engineering Portland State University Portland OR USA OHSU Augmentative Communication Clinic Oregon Health and Sciences University Portland OR USA

In the diagnosis and treatment of epilepsy, long-term monitoring may be required to document and study interictal activities such as interictal spikes. However, visual inspection of the EEG done by an expert is too time consuming and researchers normally resort to automatic detection methods. We describe a new EEG user-guided interictal spike detection algorithm that only requires the user to annotate a few spikes. We use the annotations to build a template that captures the relevant features of spikes, and then use Mean Squared Error (MSE) test to detect all of the other spikes in the recording. The detected events are rank ordered so that the user can easily identify the true spikes and their time of occurrence. The true spikes are then annotated to the EEG signals and reported to the EEG expert for further evaluation. This design provides a compromise between the enormous time commitments necessary to annotate recordings by hand and the inability of fully-automatic spike detection algorithms to account for the variability between subjects. Because spike morphology and spatial distribution change considerably when patients go through cycles of wake and sleep in long-term monitoring, this detection algorithm uses multichannel multiple templates to detect more than one type of event. The algorithm is able to achieve an average sensitivity of 96% and an average of 4.8 false detections/ hour.

关键词： Electroencephalography Brain modeling Detectors Feature extraction signal processing algorithms Epilepsy Morphology

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EEG and MRI data fusion for early diagnosis of Alzheimer's disease

EEG and MRI data fusion for early diagnosis of Alzheimer's d...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： Tejash Patel Robi Polikar Christos Davatzikos Christopher M. Clark Signal Processing and Pattern Recognition Laboratory of the Electrical and Computer Engineering Department Rowan University Glassboro NJ USA Department of Radiology University of Pennsylvania Philadelphia PA USA Department of Neurology University of Pennsylvania Philadelphia PA USA

The prevalence of Alzheimer's disease (AD) is rising alarmingly as the average age of our population increases. There is no treatment to halt or slow the pathology responsible for AD, however, new drugs are promising to reduce the rate of progression. On the other hand, the efficacy of these new medications critically depends on our ability to diagnose AD at the earliest stage. Currently AD is diagnosed through longitudinal clinical evaluations, which are available only at specialized dementia clinics, hence beyond financial and geographic reach of most patients. Automated diagnosis tools that can be made available to community hospitals would therefore be very beneficial. To that end, we have previously shown that the event related potentials obtained from different scalp locations can be effectively used for early diagnosis of AD using an ensemble of classifiers based decision fusion approach. In this study, we expand our data fusion approach to include MRI based measures of regional brain atrophy. Our initial results indicate that ERPs and MRI carry complementary information, and the combination of these heterogeneous data sources using a decision fusion approach can significantly improve diagnostic accuracy.

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Ultrabroadband Biphotons Generated via Chirped Quasi-Phase-Matched Optical Parametric Down-Conversion

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Physical Review Letters 2008年第18期100卷 183601-183601页

作者： Magued B. Nasr Silvia Carrasco Bahaa E. A. Saleh Alexander V. Sergienko Malvin C. Teich Juan P. Torres Lluis Torner David S. Hum Martin M. Fejer Quantum Imaging Laboratory* Departments of Electrical & Computer Engineering and Physics Boston University Boston Massachusetts 02215 USA ICFO-Institut de Ciencies Fotoniques and Department of Signal Theory and Communications Universitat Politecnica de Catalunya Mediterranean Technology Park 08860 Castelldefels (Barcelona) Spain E. L. Ginzton Laboratory Stanford University Stanford California 94305 USA

We generate ultrabroadband biphotons via the process of spontaneous parametric down-conversion (SPDC) in quasi-phase-matched nonlinear gratings that have a linearly chirped wave vector. By using these ultrabroadband biphotons (300-nm bandwidth), we measure the narrowest Hong-Ou-Mandel dip to date, having a full width at half maximum of 7.1 fs. This enables the generation of a high flux of nonoverlapping biphotons with ultrabroad bandwidth, thereby promoting the use of SPDC light in many nonclassical applications.

关键词： .SPDC linearly chirped week ending ultranarrow quasi-phase-matched QOCT parametric down-conversion Ultrabroadband Biphotons

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Digitally Enhanced Analog Circuits: System Aspects

Digitally Enhanced Analog Circuits: System Aspects

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2008 IEEE International Symposium on Circuits and Systems (ISCAS 2008), vol.2

作者： Boris Murmann Christian Vogel Heinz Koeppl Department of Electrical Engineering University of Stanford Stanford CA USA Signal Processing and Speech Communication Laboratory Graz University of Technology Graz Austria School of Communication and Computer Sciences EPF Lausanne Lausanne Switzerland

An overview of digital enhancement techniques for analog circuits is presented. Recent research suggests that the high density and low energy of digital circuits can be leveraged to enable a new generation of interface electronics that is based on minimal precision, low complexity analog blocks. Today, examples of enhancement schemes can be found in diverse applications and include nonlinearity compensation of ADCs, predistortion of power amplifiers and mismatch calibration in radio receivers. Since it is often difficult to identify commonalities among these different, but conceptually related schemes, this tutorial paper aims to provide a unified and system-oriented perspective of the field.

关键词： Analog circuits Calibration signal processing Microprocessors Circuit noise Digital circuits Linearity Power dissipation signal resolution Digital signal processing

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Performance of a self-paced brain computer interface on data contaminated with eye-movement artifacts and on data recorded in a subsequent session

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Computational Intelligence and Neuroscience 2008年第unknown期2008卷 1-13页

作者： Fatourechi, Mehrdad Ward, Rabab K. Birch, Gary E. Image and Signal Processing Laboratory Department of Electrical and Computer Engineering University of British Columbia Vancouver BC V6T 1Z4 Canada Institute for Computing Information and Cognitive Systems University of British Columbia Vancouver BC V6T 1Z4 Canada Neil Squire Society Burnaby BC V5M 3Z3 Canada

The performance of a specific self-paced BCI (SBCI) is investigated using two different datasets to determine its suitability for using online: (1) data contaminated with large-amplitude eye movements, and (2) data recorded in a session subsequent to the original sessions used to design the system. No part of the data was rejected in the subsequent session. Therefore, this dataset can be regarded as a pseudo-online test set. The SBCI under investigation uses features extracted from three specific neurological phenomena. Each of these neurological phenomena belongs to a different frequency band. Since many prominent artifacts are either of mostly low-frequency (e.g., eye movements) or mostly high-frequency nature (e.g., muscle movements), it is expected that the system shows a fairly robust performance over artifact-contaminated data. Analysis of the data of four participants using epochs contaminated with large-amplitude eye-movement artifacts shows that the system's performance deteriorates only slightly. Furthermore, the system's performance during the session subsequent to the original sessions remained largely the same as in the original sessions for three out of the four participants. This moderate drop in performance can be considered tolerable, since allowing artifact-contaminated data to be used as inputs makes the system available for users at ALL times.

关键词： .Brain computer Data Contaminated Eye-Movement Artifacts Subsequent Session Recorded in Subsequent SBCI contaminated with large-amplitude neurological phenomena

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A Journey from signal processing to surveillance

A Journey from signal processing to surveillance

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2007 IEEE Conference on Advanced Video and signal Based Surveillance, AVSS 2007

作者： Chen, Tsuhan Advanced Multimedia Processing Laboratory Dept. of Electrical Computer Engineering Carnegie Mellon University Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA United States IEEE Signal Processing Society

ISBN: (纸本)9781424416967

Traditionally, signal processing is considered simply lowlevel processing. In the past decade, however, signal processing has grown to become the area where a variety of tools are created to solve high-level problems that conventionally would be studied by computer vision or machine learning researchers exclusively. For example, multiresolution analysis created popular image features like SIFT (scale-invariant feature transform), and statistical analysis gave birth to graphical models such as HMM (hidden Markov models) and topic models. In this talk, we will use one application to illustrate this growth of signal processing: object discovery, i.e., extracting the "object of interest" from a set of images in a completely unsupervised manner. Often based on image features like SIFT, and the topic models, object discovery has recently attracted a lot of attention in video content extraction. In this talk, we will outline this approach and extend it from still images to motion videos. We will propose a novel spatial-temporal framework that applies statistical models to both appearance modeling and motion modeling. The spatial and temporal models are integrated so that motion ambiguities can be resolved by appearance, and appearance ambiguities can be resolved by motion. In addition, we can extract hierarchical relationships among objects, completely driven by data without any manual labeling. This framework finds application in video retrieval (e.g., for YouTube or Google Video) and video surveillance. © 2007 IEEE.

关键词： Hidden Markov models

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Challenges in the Design of Adaptive, Intelligent and Cognitive Systems

Challenges in the Design of Adaptive, Intelligent and Cognit...

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IEEE International Conference on Cognitive Informatics

作者： W. Kinsner Institute of Industrial Mathematical Sciences Telecommunications Research Laboratory Canada Signal and Data Compression Laboratory Department of Electrical and Computer Engineering University of Manitoba Winnipeg MAN Canada

Numerous attempts are being made to develop machines that could act not only autonomously, but also in an increasingly intelligent and cognitive manner. Such cognitive machines ought to be aware of their environments which include not only other machines, but also human beings. Such machines ought to understand the meaning of information in more human-like ways by grounding knowledge in the physical world and in the machines' own goals. The motivation for developing such machines range from self-evidenced practical reasons such as the expense of computer maintenance, to wearable computing in health care, and gaining a better understanding of the cognitive capabilities of the human brain. To achieve such an ambitious goal requires solutions to many problems, ranging from human perception, attention, concept creation, cognition, consciousness, executive processes guided by emotions and value, and symbiotic conversational human-machine interactions. This paper discusses some of the challenges emerging from this new design paradigm, including systemic problems, design issues, teaching the subjects to undergraduate students in electrical and computer engineering programs, research related to design.

关键词： Intelligent systems Humans Machine intelligence Wearable computers Grounding Medical services Cognition Symbiosis Man machine systems Education

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