Eighteenth Convention of Electrical and Electronics Engineers in Israel最新文献

{"title":"Analysis of sounds from occluded arteries by using a linear array of microphones","authors":"Y. Roffeh, S. Einav","doi":"10.1109/EEIS.1995.514154","DOIUrl":"https://doi.org/10.1109/EEIS.1995.514154","url":null,"abstract":"The development of a non-invasive method for measuring of disturbances and obstructions in flow patterns inside the arterial system is a valuable tool for medical diagnostic purposes. A complete mapping of the pressure field and its correlation to the flow field and to the characteristics of the occlusion (stenosis) are goals that have not yet been attained, and are of extreme importance to the medical, scientific, and bioengineering communities. Disturbed blood flow can generate arterial sounds that can be heard directly over the affected area and transmitted to another area over the skin. In recent years, several investigators suggested that audio-frequency analysis of vascular sounds may provide a non-invasive method that may be used to quantify arterial stenosis. A new high resolution array signal processing technique is proposed as a diagnostic tool to utilize the sounds that originate in occluded arteries, specifically determination of abnormal flow conditions. These sounds can be measured by non-invasive, sensitive and acoustic microphone linear array placed on the skin. The use of \"Inverse Problem\" technique proposed to localize and characterize abnormal sounds being generated in occluded arteries. The solution is obtained by deriving an accurate set of linear equations related to \"input/output\" signals obtained in array of microphones, and then stored in a \"weight\" matrix. A computer simulation for non-coherent sources located at different coordinates show a quite agreeable solution of a problem, by enhancing the spatial locations of the simulated sources. We built an experiment model that demonstrates different flow conditions in constricted tubes. Measuring sounds are picked by a linear array of 16 microphones placed separated from the constricted tube. In an experimental system we examine first the frequency content of constricted tube and then we derive a spatial resolution by using an inverse problem technique. Representative computer simulations and measured results obtained in experimental model demonstrate the potential of our approach.","PeriodicalId":219797,"journal":{"name":"Eighteenth Convention of Electrical and Electronics Engineers in Israel","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125642168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transmission line based power averaging","authors":"D. Shmilovitz, S. Singer","doi":"10.1109/EEIS.1995.513789","DOIUrl":"https://doi.org/10.1109/EEIS.1995.513789","url":null,"abstract":"A method for pulsating power filtration is suggested in this paper. The main principle for this kind of solution is based on the fact that the time of appearance of a pulse traveling on a channel (transmission line in this case) is directly proportional to the electrical length of the channel. Thus, if power pulses are fed into a group of transmission lines, simultaneously, they may reach the end points sequentially, if certain measures are taken. The main features of the topology are: (a) opposite to other low pass filters this kind of filter is capable of transforming a rectangular voltage pulse into rectangular pulse of wider duration and lower magnitude, yet with the very same rise and fall time; (b) the switching elements (the system consists of) need to withstand much lower peak power than the pulse input power; (c) the system is suitable for extremely high frequencies and for very short rise and decay times of rectangular pulses.","PeriodicalId":219797,"journal":{"name":"Eighteenth Convention of Electrical and Electronics Engineers in Israel","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128741342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"HMM phoneme recognition with supervised training and Viterbi algorithm","authors":"T. Vaich, A. Cohen","doi":"10.1109/EEIS.1995.513820","DOIUrl":"https://doi.org/10.1109/EEIS.1995.513820","url":null,"abstract":"An HMM continuous Hebrew phoneme recognition system, that requires no manual segmentation for its training was developed. A relatively small Hebrew data base was acquired for training and recognition of phonemes in continuous speech. One of the main problems in phoneme recognition, that of manual segmentation of the training data base, was overcome by a special training algorithm. The Viterbi algorithm was used in the recognition stage, and the evaluation of the results was done with the Levenshtein distance measure. Initial recognition results of Hebrew phonemes for speaker independent, text dependent cases were 69.4% correct phoneme recognition.","PeriodicalId":219797,"journal":{"name":"Eighteenth Convention of Electrical and Electronics Engineers in Israel","volume":"2012 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116955746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Highlights of the mobile communications channel research","authors":"J. Shapira","doi":"10.1109/EEIS.1995.513794","DOIUrl":"https://doi.org/10.1109/EEIS.1995.513794","url":null,"abstract":"Mobile cellular radio communications is a demanding service. The environment-rich in shadowing or otherwise scattering objects-stresses the performance of the communications systems, which strive to achieve both a high grade of service and a high spectral efficiency. The means of mitigating the impairments of the dispersive and fading channels affect the complexity of the system. A compact characterization of the channels, in terms that are useful to the system designers and performance evaluators, is the objective of the Joint Task Group of URSI (the International Union for Radio Science), chaired by the author. 5 workshops have been held during the last 4 years. A substantial part of the channel characterization effort has shifted from generic statistical models to the underlying physical mechanisms, the deterministic features and the proper interpretation of measurements. A review of the ongoing research, in the community and the author's contributions, is discussed, to include an analysis of a measurement campaign in the US, providing evidence of the channel structure.","PeriodicalId":219797,"journal":{"name":"Eighteenth Convention of Electrical and Electronics Engineers in Israel","volume":"582 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115853764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel approach in scanning acoustic microscopy-the resonance mode","authors":"G. Golan, R. Aviv, A. Kenyon, G. Griffel, C. Pitt","doi":"10.1109/EEIS.1995.513809","DOIUrl":"https://doi.org/10.1109/EEIS.1995.513809","url":null,"abstract":"A novel Virtual Cavity Scanning Acoustic Microscope (VSAM), in which a resonating Fabry-Perot acoustic cavity is formed by a PZT plate mirror and an acoustic lens, has been studied and demonstrated. Investigation of the enhancement of nonlinear interactions created by small spheres in an air gap bubble shape in the acoustic resonance cavity are discussed. This novel approach offers greater image accuracy, higher resolution capabilities and better selectivity than a conventional SAM due to the significant increase in the dynamic range of the acoustic signals. Typical applications of VSAM are for surface and subsurface Non Destructive Evaluations (NDE) imaging, especially for imaging bonds, voids and dis-continous regions like air gaps between any two solids. Dis-continous bonds or voids yield strong reflections, leading to high contrast acoustic images to reveal the mechanical properties of these bonded or disbonded regions.","PeriodicalId":219797,"journal":{"name":"Eighteenth Convention of Electrical and Electronics Engineers in Israel","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127397798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Controlled semiconductor capacitors","authors":"G. Ashkinazi, B. Meyler, M. Nathan, L. Zolotarevski, O. Zolotarevski","doi":"10.1109/EEIS.1995.513836","DOIUrl":"https://doi.org/10.1109/EEIS.1995.513836","url":null,"abstract":"This paper discusses the development of a new class of semiconductor devices-\"controlled semiconductor capacitors\" (CC's) in which the capacitance can be varied using an external control of radiation (e.g., light) or current. The high-speed control of a capacitance by an external source has had no satisfactory solution to date. We have developed the theory and simulation and design methods, and have obtained experimental results which allow us to address this problem. In principle the problem of capacitance control can be solved using electrical schemes of various combinations of traditional discrete element such as capacitors plus semiconductor diodes, or only diodes. However, with silicon devices such schemes are impractical and uneconomical. We show that controlled capacitors can be designed practically and effectively using two GaAs PIN diodes with a near-fully compensated i-region of controllable width, or a PIN diode and a high voltage GaAs Schottky diode.","PeriodicalId":219797,"journal":{"name":"Eighteenth Convention of Electrical and Electronics Engineers in Israel","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125897134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Compression of high-quality audio signals using adaptive filterbanks and a zero-tree coder","authors":"Y. Karelic, D. Malah","doi":"10.1109/EEIS.1995.513823","DOIUrl":"https://doi.org/10.1109/EEIS.1995.513823","url":null,"abstract":"In this work we present a subband coding system for compressing high-quality audio signals. Two alternative subband decomposition schemes are considered: One consists of time-varying analysis and synthesis filterbanks that adapt their structure to the time-varying properties of the input signal; the other is based on decomposition of each block of samples separately. Both schemes are based on the wavelet packets theory and the best-basis selection algorithm. The coder and decoder used in the system are based on the zero-tree algorithm which was originally developed for coding still images and is adapted here for coding audio signals. The performance of the proposed system is shown to be superior to the MPEG-Audio layer I standard, achieving an improvement of up to 10.6 dB in segmental SNR at output bit rate of 64 kbit/sec and up to 6.5 dB at output bit rate of 128 kbit/sec, for a variety of music signals. However, it turns out that most of the improvement is due to the zero-tree coding algorithm.","PeriodicalId":219797,"journal":{"name":"Eighteenth Convention of Electrical and Electronics Engineers in Israel","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121256501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On collision resolution protocols for channels with long propagation delay","authors":"T. Segalov, E. Plotnik, I. Bar-David","doi":"10.1109/EEIS.1995.514186","DOIUrl":"https://doi.org/10.1109/EEIS.1995.514186","url":null,"abstract":"Simulation results on the performance of multiple access protocols with long propagation delay are presented. It is shown that there are situations where slotted Aloha protocols with multiple transmissions of packets, provide better delay throughput characteristics than the classical slotted Aloha protocol with single transmission.","PeriodicalId":219797,"journal":{"name":"Eighteenth Convention of Electrical and Electronics Engineers in Israel","volume":"194 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131832737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A study of finite size power isotropic radiators","authors":"Haim Matzner, M. Milgrom, S. Shtrikman","doi":"10.1109/EEIS.1995.513780","DOIUrl":"https://doi.org/10.1109/EEIS.1995.513780","url":null,"abstract":"A class of localized current sources that radiate power isotropically is presented. Their far-fields are given as well as the symmetries of the associated polarization distributions, and, in addition, the multi-pole expansion of the fields of these radiators is calculated.","PeriodicalId":219797,"journal":{"name":"Eighteenth Convention of Electrical and Electronics Engineers in Israel","volume":"601 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133339334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intelligent scan image progressive transmission","authors":"M. Sherman, R. Ginosar","doi":"10.1109/EEIS.1995.513795","DOIUrl":"https://doi.org/10.1109/EEIS.1995.513795","url":null,"abstract":"Progressive transmission of high resolution still images over low speed channels enables the receiver to view an interpolated version of the image even before the complete image data have arrived. Previously proposed methods are based on sub-sampling on regular grids, icons, and linear encoding based on Gaussian/Laplacian pyramids. A novel progressive image transmission method is proposed, employing Intelligent Scan (I/S) encoding. It comprises an image encoding and fast image interpolation steps. Pixels are transmitted in the order in which they are most useful to human image recognition, rather than in the order in which they are arranged in the image file.","PeriodicalId":219797,"journal":{"name":"Eighteenth Convention of Electrical and Electronics Engineers in Israel","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131071838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}