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Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109)最新文献

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Electric intensity distributions in planer stratified slabs illuminated with shaped electromagnetic waves 异形电磁波照射下平面层状板的电强度分布
Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109) Pub Date : 1998-02-24 DOI: 10.1109/NRSC.1998.711452
E. Khaled
{"title":"Electric intensity distributions in planer stratified slabs illuminated with shaped electromagnetic waves","authors":"E. Khaled","doi":"10.1109/NRSC.1998.711452","DOIUrl":"https://doi.org/10.1109/NRSC.1998.711452","url":null,"abstract":"Internal intensity distributions in stratified dielectric slabs illuminated with shaped electromagnetic waves are investigated. Mathematical analysis are presented for a model of any number of slabs of different electrical and physical properties. The method is based on the desired field distribution in each slab. The desired field distribution in any layer is decomposed into basis functions. The expansion coefficients are calculated using the boundary conditions. Computed results are shown for a model of four slabs and the desired electric field distribution is Gaussian shaped wave. The calculated results for the electric field intensity distributions are illustrated in the last layer. The presented method may help the investigators to design electromagnetic sources to generate the desired field distributions.","PeriodicalId":128355,"journal":{"name":"Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109)","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121744253","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}
引用次数: 0
A generalised site shielding procedure for radio system planning at microwave frequencies 微波频率无线电系统规划的通用场地屏蔽程序
Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109) Pub Date : 1998-02-24 DOI: 10.1109/NRSC.1998.711445
M. Al-Nuaimi
{"title":"A generalised site shielding procedure for radio system planning at microwave frequencies","authors":"M. Al-Nuaimi","doi":"10.1109/NRSC.1998.711445","DOIUrl":"https://doi.org/10.1109/NRSC.1998.711445","url":null,"abstract":"The author begins by discussing the requirements for a generalized site shielding procedure. The results of detailed studies into the propagation modes and factors affecting the relative levels of wanted and unwanted signals received in the shadow of an obstacle are presented. Prediction models for diffraction, reflection and scatter from buildings are presented. These can be applied to determine the site shielding factor (SSF) obtained from a building and the limitation on the SSF caused by lateral contributions, expected in urban radio path geometries. In addition the effects of vegetation media which may be present in urban areas can also be quantified.","PeriodicalId":128355,"journal":{"name":"Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128059406","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}
引用次数: 2
Efficiency of analytical transforms for image compression 图像压缩分析变换的效率
Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109) Pub Date : 1998-02-24 DOI: 10.1109/NRSC.1998.711461
A. Ragab, A. Mohamed, M. Hamid
{"title":"Efficiency of analytical transforms for image compression","authors":"A. Ragab, A. Mohamed, M. Hamid","doi":"10.1109/NRSC.1998.711461","DOIUrl":"https://doi.org/10.1109/NRSC.1998.711461","url":null,"abstract":"Digital image transforms, for decorrelating image pixels, have received wide spread interest in the literature. Analytical transforms play a great role in the gray level decorrelation and energy compaction of the image and hardly affect the performance of the image compression technique. This paper provides a comparison of the bit rate reduction capability and signal to noise ratio among five transforms; namely, Karhunen-Loeve transform (KLT), discrete cosine transform (DCT), discrete Hartley transform (DHT), discrete Gabor transform (DGT), and the discrete wavelet transform (DWT), where they have shown the most promise in image compression coding systems. The coefficients of the transform are truncated with a specified threshold and the bit rate is computed after Huffman coding. The image is reconstructed from the truncated version of the coefficient matrix. Peak signal to noise ratio and compression ratio are considered to evaluate the efficiency of the analytical transform. The error image between the original and the reconstructed image is computed to follow the error distribution over the image.","PeriodicalId":128355,"journal":{"name":"Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134176005","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}
引用次数: 13
Design of two-channel FIR QMF banks satisfying prescribed specifications 满足规定规格的双通道FIR QMF库的设计
Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109) Pub Date : 1998-02-24 DOI: 10.1109/NRSC.1998.711468
A. Tawfik, E. Abdel-Raheem
{"title":"Design of two-channel FIR QMF banks satisfying prescribed specifications","authors":"A. Tawfik, E. Abdel-Raheem","doi":"10.1109/NRSC.1998.711468","DOIUrl":"https://doi.org/10.1109/NRSC.1998.711468","url":null,"abstract":"A method is proposed for the design of two-channel linear-phase FIR QMF banks satisfying prescribed reconstruction and stopband errors. The method is integrated with a weighted minimax design of QMF banks based on an iterative method proposed by Chen and Lee (1992) with certain modifications based on the weighted least-squares (WLS) updating scheme proposed by Sunder and Ramachandran (1994). The method is simple and a design example is presented.","PeriodicalId":128355,"journal":{"name":"Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123948399","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}
引用次数: 1
A new hierachical routing method for broadband ISDN 一种新的宽带ISDN分层路由方法
Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109) Pub Date : 1998-02-24 DOI: 10.1109/NRSC.1998.711469
I. Ali, A. El-Sawy, H. Mouftah
{"title":"A new hierachical routing method for broadband ISDN","authors":"I. Ali, A. El-Sawy, H. Mouftah","doi":"10.1109/NRSC.1998.711469","DOIUrl":"https://doi.org/10.1109/NRSC.1998.711469","url":null,"abstract":"A new hierarchical routing model for broadband networks is proposed and one of the problems facing the design of the hierarchical routing model is addressed. A brief description of the PNNI hierarchical routing model is given and a new hierarchical model that proves to be simpler and requires less storage than the PNNI model is proposed. The problem addressed is the choice of the number of levels in the hierarchy and the group size at each level. The optimization criterion for this problem is the minimization of storage required at each node to store the topology status information necessary for routing decision.","PeriodicalId":128355,"journal":{"name":"Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122019517","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}
引用次数: 1
Hardware realization of analog CMOS current-mode minimum circuit 模拟CMOS电流模最小电路的硬件实现
Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109) Pub Date : 1998-02-24 DOI: 10.1109/NRSC.1998.711509
M. Yakout, E. El-Masry, A. I. Abdel-Fattah
{"title":"Hardware realization of analog CMOS current-mode minimum circuit","authors":"M. Yakout, E. El-Masry, A. I. Abdel-Fattah","doi":"10.1109/NRSC.1998.711509","DOIUrl":"https://doi.org/10.1109/NRSC.1998.711509","url":null,"abstract":"Fuzzy systems can be implemented by software or hardware. The software approach is complex and its operation speed is low particularly in real-time applications. On the other hand, the hardware implementations (digital and/or analog) of fuzzy systems yield high speed and high efficiency for real-time applications. Since fuzzy systems normally have output with amplitude that varies continuously from 0 to 1, then the analog implementation is the most suitable choice. Besides, analog circuits have higher speed and lower power consumption than their digital counterparts. In this paper, a new current mode, multiple input minimum circuit is proposed. It has many features such as high speed, small area, low power dissipation and compatibility with VLSI implementation. Also, the circuit does not need any preprocessing (normalization) of the input currents before calculating the minimum. These features make it suitable as a building block in real-time computational systems such as fuzzy or artificial neural networks.","PeriodicalId":128355,"journal":{"name":"Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130766990","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}
引用次数: 3
Effect of finite buffer capacity on the performance of ATM networks 有限缓冲容量对ATM网络性能的影响
Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109) Pub Date : 1998-02-24 DOI: 10.1109/NRSC.1998.711499
H. El-Badawy, S. El-Ramly
{"title":"Effect of finite buffer capacity on the performance of ATM networks","authors":"H. El-Badawy, S. El-Ramly","doi":"10.1109/NRSC.1998.711499","DOIUrl":"https://doi.org/10.1109/NRSC.1998.711499","url":null,"abstract":"The performance of an ATM switch of a space division architecture with finite FIFO output buffer is considered. The input traffic is modeled by identical Bernoulli processes. The presented analytical approach is based on a queueing model which describes the finite queue occupancy distribution. The evaluation of the cell loss and cell mean delay is compared with previously presented analytical results. It is found that the presented simple model is suitable for determining the finite buffer effect on the ATM network performance in spite of its simplicity and its analytical tractability. An asymptotic relation is obtained between the offered load and the buffer size that gives a constant cell loss behavior. Moreover, the outstanding physical meaning of the presented procedure gives a deep insight into the ATM switch performance parameters as to the network offered load and the switch buffer capacity.","PeriodicalId":128355,"journal":{"name":"Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130791685","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}
引用次数: 0
An efficient design algorithm of N-band IIR digital filters 一种n波段IIR数字滤波器的高效设计算法
Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109) Pub Date : 1998-02-24 DOI: 10.1109/NRSC.1998.711482
A. I. Saleh, G. El-Raheem, G.E. Fahmy
{"title":"An efficient design algorithm of N-band IIR digital filters","authors":"A. I. Saleh, G. El-Raheem, G.E. Fahmy","doi":"10.1109/NRSC.1998.711482","DOIUrl":"https://doi.org/10.1109/NRSC.1998.711482","url":null,"abstract":"In this paper, the design of an N-subband coding scheme employing IIR digital filters, is investigated. It has been shown that the system reduces to the design of a single IIR filter from which the rest of the analysis and synthesis filters are derived. A simple rapidly convergent algorithm is presented for the design of this filter. Apart from ensuring stability, flexibility of meeting any stringent specifications, the design algorithm results in equiripple loss behavior over its bands of interest. Illustrative examples are given.","PeriodicalId":128355,"journal":{"name":"Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109)","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116834242","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}
引用次数: 3
Wideband measurements and modeling of the indoor radio channel at 10 GHz. I. Frequency domain analysis 10ghz室内无线信道的宽带测量和建模。一、频域分析
Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109) Pub Date : 1998-02-24 DOI: 10.1109/NRSC.1998.711458
A. Abouraddy, S. Elnoubi, A. El-Shafei
{"title":"Wideband measurements and modeling of the indoor radio channel at 10 GHz. I. Frequency domain analysis","authors":"A. Abouraddy, S. Elnoubi, A. El-Shafei","doi":"10.1109/NRSC.1998.711458","DOIUrl":"https://doi.org/10.1109/NRSC.1998.711458","url":null,"abstract":"Measurements concerning the indoor radio channel are presented. The frequency domain is discussed. The transfer of the 10 GHz band with a 1 GHz bandwidth is investigated using a swept frequency method depending on a network analyzer. The spaced frequency correlation function is obtained and its 3 dB bandwidth computed.","PeriodicalId":128355,"journal":{"name":"Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134070268","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}
引用次数: 6
Adaptive object tracking and video compression with dynamic contours 动态轮廓的自适应目标跟踪和视频压缩
Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109) Pub Date : 1998-02-24 DOI: 10.1109/NRSC.1998.711444
Yutao Feng, E. Gelenbe
{"title":"Adaptive object tracking and video compression with dynamic contours","authors":"Yutao Feng, E. Gelenbe","doi":"10.1109/NRSC.1998.711444","DOIUrl":"https://doi.org/10.1109/NRSC.1998.711444","url":null,"abstract":"We present a novel video compression system resulting in very low bit rates, using dynamic object oriented compression. Our method separates important objects from the background and from trivial details, so as to keep good visual quality of the objects of interest. The resulting bit rate can be significantly reduced by sacrificing information on less relevant parts of the scene, or from portions of the video sequence which are of less interest to the end users. The method is based on an active dynamic contour algorithm which tracks the external contour of designated objects, and which we improve to provide more accurate dynamic tracking. The performance of the object tracking algorithm, as well as of our compression scheme are presented. Experimental results concerning bit rates and video quality are provided and compared with respect to the standard H.263.","PeriodicalId":128355,"journal":{"name":"Proceedings of the Fifteenth National Radio Science Conference. NRSC '98 (Cat. No.98EX109)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116330648","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}
引用次数: 3
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