Pub Date : 2004-03-18DOI: 10.1109/NRSC.2004.239923
E. Saad, M. El-dosoky
Continuous-wave ultrasonic tomography is an imaging technique, which is used to produce an image (in a form of "slices") of the body (as in X-ray tomography). This imaging technique is an application of Doppler effect. Any object consists of scatterers (targets) at different positions. As rotating this object around an axis of rotation (with respect to a stationary ultrasonic beam) with certain speed, the position of each scatterer corresponds to a certain Doppler shift; the scatterers can be imaged at different positions. The final image of each scatterer can be reconstructed from the resulted power spectra (from the rotating object at different positions) by using a theorem called back-projection. This paper introduces the mathematical analysis of this imaging technique, and the main problems of it. New algorithm for reconstructing the images of rotating object is also discussed.
{"title":"An optimum design of continuous-wave ultrasonic tomographic technique","authors":"E. Saad, M. El-dosoky","doi":"10.1109/NRSC.2004.239923","DOIUrl":"https://doi.org/10.1109/NRSC.2004.239923","url":null,"abstract":"Continuous-wave ultrasonic tomography is an imaging technique, which is used to produce an image (in a form of \"slices\") of the body (as in X-ray tomography). This imaging technique is an application of Doppler effect. Any object consists of scatterers (targets) at different positions. As rotating this object around an axis of rotation (with respect to a stationary ultrasonic beam) with certain speed, the position of each scatterer corresponds to a certain Doppler shift; the scatterers can be imaged at different positions. The final image of each scatterer can be reconstructed from the resulted power spectra (from the rotating object at different positions) by using a theorem called back-projection. This paper introduces the mathematical analysis of this imaging technique, and the main problems of it. New algorithm for reconstructing the images of rotating object is also discussed.","PeriodicalId":194287,"journal":{"name":"Proceedings of the Twenty-First National Radio Science Conference, 2004. NRSC 2004.","volume":"207 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132207323","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}
Pub Date : 2004-03-16DOI: 10.1109/NRSC.2004.239891
A. Zekry, M. A. Elgendy
The photovoltaic pumping (PVP) is one of the more promising applications of renewable sources in the energy supply of agricultural process. However, the implementation of PVP systems is still scarce especially because the lack of standard criteria relating the involved variables such as meteorological parameters, PV panels characteristics and pump performance. In this work, the effects of meteorological parameters, pump selection and tilt angle variation on the PVP system performance are studied using the SICADT (solar irrigation computer aided design tool) simulation program developed by the authors. This study is accomplished utilizing a standard PVP system comprised of a PV array; an inverter and a submersible electric driven centrifugal pump. This system can be used for pumping the subterranean water in North Sinai region for drip irrigation network.
{"title":"Estimated performance of photovoltaic irrigation systems under different operating conditions","authors":"A. Zekry, M. A. Elgendy","doi":"10.1109/NRSC.2004.239891","DOIUrl":"https://doi.org/10.1109/NRSC.2004.239891","url":null,"abstract":"The photovoltaic pumping (PVP) is one of the more promising applications of renewable sources in the energy supply of agricultural process. However, the implementation of PVP systems is still scarce especially because the lack of standard criteria relating the involved variables such as meteorological parameters, PV panels characteristics and pump performance. In this work, the effects of meteorological parameters, pump selection and tilt angle variation on the PVP system performance are studied using the SICADT (solar irrigation computer aided design tool) simulation program developed by the authors. This study is accomplished utilizing a standard PVP system comprised of a PV array; an inverter and a submersible electric driven centrifugal pump. This system can be used for pumping the subterranean water in North Sinai region for drip irrigation network.","PeriodicalId":194287,"journal":{"name":"Proceedings of the Twenty-First National Radio Science Conference, 2004. NRSC 2004.","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123112873","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}
Pub Date : 2004-03-16DOI: 10.1109/NRSC.2004.240363
S. Zainud-Deen, N.F.M. Soliman, A. Shaalan, K. Hussein
Conical Archimedes spiral antennas are designed to produce radiation patterns of cardoid or conical shapes for satellite applications. The method of moments is used to calculate the current distribution on the spiral arms. The radiation pattern, gain, polarization, and input impedance are presented. The standing-wave ratio (VSWR) and the reflection coefficient of the antenna are investigated over a wide frequency band. It is shown that the radiation pattern of this antenna can be easily shaped by setting the geometrical parameters of the conical spiral such as the cone angle and the spiral constant. It is noticed that the conical spiral antenna has a wide bandwidth over which the radiation characteristics and the input impedance are maintained satisfactory.
{"title":"Characteristics of two-arm wire conical spiral antennas","authors":"S. Zainud-Deen, N.F.M. Soliman, A. Shaalan, K. Hussein","doi":"10.1109/NRSC.2004.240363","DOIUrl":"https://doi.org/10.1109/NRSC.2004.240363","url":null,"abstract":"Conical Archimedes spiral antennas are designed to produce radiation patterns of cardoid or conical shapes for satellite applications. The method of moments is used to calculate the current distribution on the spiral arms. The radiation pattern, gain, polarization, and input impedance are presented. The standing-wave ratio (VSWR) and the reflection coefficient of the antenna are investigated over a wide frequency band. It is shown that the radiation pattern of this antenna can be easily shaped by setting the geometrical parameters of the conical spiral such as the cone angle and the spiral constant. It is noticed that the conical spiral antenna has a wide bandwidth over which the radiation characteristics and the input impedance are maintained satisfactory.","PeriodicalId":194287,"journal":{"name":"Proceedings of the Twenty-First National Radio Science Conference, 2004. NRSC 2004.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123756590","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}
Pub Date : 2004-03-16DOI: 10.1109/NRSC.2004.240427
H. Elkamchouchi, K. Elshenawy, H.A. Shaban
The purpose of this paper is to provide digital signature schemes with appendix and message recovery in the real and Gaussian integers' domains. The proposed schemes employ the idea of combining the integer factorization, and the generalized discrete logarithm problems. These proposed schemes are valid for the two new cryptosystems namely, the quadratic-exponentiation randomized (QER) and the Beta cryptosystems. An overview of the two cryptosystems and their extensions to the domain of Gaussian integers Z[i] are given. The validity of extending the digital signature schemes in Z[i] is illustrated. The proposed digital signature schemes are efficient. Extensions of the digital signature scheme with message recovery to Z[i] have many advantages. The digital signature schemes in the real and Z[i] domains are illustrated with extensive numerical examples.
{"title":"New digital signature schemes in the real and Gaussian integers' domains","authors":"H. Elkamchouchi, K. Elshenawy, H.A. Shaban","doi":"10.1109/NRSC.2004.240427","DOIUrl":"https://doi.org/10.1109/NRSC.2004.240427","url":null,"abstract":"The purpose of this paper is to provide digital signature schemes with appendix and message recovery in the real and Gaussian integers' domains. The proposed schemes employ the idea of combining the integer factorization, and the generalized discrete logarithm problems. These proposed schemes are valid for the two new cryptosystems namely, the quadratic-exponentiation randomized (QER) and the Beta cryptosystems. An overview of the two cryptosystems and their extensions to the domain of Gaussian integers Z[i] are given. The validity of extending the digital signature schemes in Z[i] is illustrated. The proposed digital signature schemes are efficient. Extensions of the digital signature scheme with message recovery to Z[i] have many advantages. The digital signature schemes in the real and Z[i] domains are illustrated with extensive numerical examples.","PeriodicalId":194287,"journal":{"name":"Proceedings of the Twenty-First National Radio Science Conference, 2004. NRSC 2004.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128503242","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}
Pub Date : 2004-03-16DOI: 10.1109/NRSC.2004.240365
K. Hussein
The electric field integral equation (EFIE) technique is applied to a triangular-patch surface model of the conical equiangular spiral antenna. The input impedance and radiation characteristics of this antenna are investigated over a wide band of frequencies. The effects of some important geometrical parameters of the antenna, such as the half-cone angle, on the antenna performance are studied. Some of the obtained results especially those concerning the input impedance, polarization and bandwidth are compared with other published theoretical and experimental results.
{"title":"Analysis of conical equiangular spiral antenna using EFIE technique","authors":"K. Hussein","doi":"10.1109/NRSC.2004.240365","DOIUrl":"https://doi.org/10.1109/NRSC.2004.240365","url":null,"abstract":"The electric field integral equation (EFIE) technique is applied to a triangular-patch surface model of the conical equiangular spiral antenna. The input impedance and radiation characteristics of this antenna are investigated over a wide band of frequencies. The effects of some important geometrical parameters of the antenna, such as the half-cone angle, on the antenna performance are studied. Some of the obtained results especially those concerning the input impedance, polarization and bandwidth are compared with other published theoretical and experimental results.","PeriodicalId":194287,"journal":{"name":"Proceedings of the Twenty-First National Radio Science Conference, 2004. NRSC 2004.","volume":"599 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116279782","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}
Pub Date : 2004-03-16DOI: 10.1109/NRSC.2004.240300
H. Elkamchouchi, M.A.E.M. Adam
In this paper, we compare the performance of different blind adaptive array algorithms in code division multiple access (CDMA) mobile systems using dynamic and static data blocks. Applying on the two algorithms, least-squares despread respread multitarget array (LSDRMTA) and least-squares despread respread multitarget constant modulus algorithm (LSDRMTCMA). The performance test assume that the channel has additive white gaussian noise (AWGN).
{"title":"A multitarget adaptive array algorithms for wireless CDMA systems","authors":"H. Elkamchouchi, M.A.E.M. Adam","doi":"10.1109/NRSC.2004.240300","DOIUrl":"https://doi.org/10.1109/NRSC.2004.240300","url":null,"abstract":"In this paper, we compare the performance of different blind adaptive array algorithms in code division multiple access (CDMA) mobile systems using dynamic and static data blocks. Applying on the two algorithms, least-squares despread respread multitarget array (LSDRMTA) and least-squares despread respread multitarget constant modulus algorithm (LSDRMTCMA). The performance test assume that the channel has additive white gaussian noise (AWGN).","PeriodicalId":194287,"journal":{"name":"Proceedings of the Twenty-First National Radio Science Conference, 2004. NRSC 2004.","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125610564","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}
Pub Date : 2004-03-16DOI: 10.1109/NRSC.2004.239856
S. El-Khamy, M. A. Mokhtar, N. El-Ganainy
In this paper, two new techniques for differential detection of changes and motion in a set of images are proposed. The suggested techniques adopt an efficient parallel complementary encoding stage applied to the image frames under study. These techniques profit from the optimum correlation properties of complete complementary code arrays. Simulation results are provided to demonstrate the efficient performance of the proposed techniques when applied to various types of images.
{"title":"New techniques for image change and motion detection based on complete complementary code arrays","authors":"S. El-Khamy, M. A. Mokhtar, N. El-Ganainy","doi":"10.1109/NRSC.2004.239856","DOIUrl":"https://doi.org/10.1109/NRSC.2004.239856","url":null,"abstract":"In this paper, two new techniques for differential detection of changes and motion in a set of images are proposed. The suggested techniques adopt an efficient parallel complementary encoding stage applied to the image frames under study. These techniques profit from the optimum correlation properties of complete complementary code arrays. Simulation results are provided to demonstrate the efficient performance of the proposed techniques when applied to various types of images.","PeriodicalId":194287,"journal":{"name":"Proceedings of the Twenty-First National Radio Science Conference, 2004. NRSC 2004.","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130831503","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}
Pub Date : 2004-03-16DOI: 10.1109/NRSC.2004.240358
S. Darwish, K. Hussein, H. Mansour
In this work, a crossed-dipole turnstile of single or double bays is designed to operate as a circularly polarized antenna for low-orbit satellites. It is shown that a single-bay turnstile in free space gives a near-isotropic radiation pattern whereas a double-bay turnstile can be designed to give a quite-isotropic radiation pattern. It is also shown that when a single-bay turnstile is placed above a square conducting plate, it gives an omni-directional radiation pattern of either balloon-like or conical shape according to its height above the square plate. An integral equation method employing a Galerkin's technique is applied to get the input impedance and power gain and to investigate the polarization characteristics of the antenna. A wire-grid model is used to represent the square conducting plate above which the antenna is placed. The validity of the wire-grid model is investigated and the accuracy of the obtained results regarding the current distribution on the square plate is realized when compared with other published results based on a real surface model of the square plate. The frequency response of the input impedance and the VSWR of the antenna in free space as well as mat when it is placed above a square conducting plate are presented, and the bandwidth of the antenna is investigated.
{"title":"Circularly polarized crossed-dipole turnstile antenna for satellites","authors":"S. Darwish, K. Hussein, H. Mansour","doi":"10.1109/NRSC.2004.240358","DOIUrl":"https://doi.org/10.1109/NRSC.2004.240358","url":null,"abstract":"In this work, a crossed-dipole turnstile of single or double bays is designed to operate as a circularly polarized antenna for low-orbit satellites. It is shown that a single-bay turnstile in free space gives a near-isotropic radiation pattern whereas a double-bay turnstile can be designed to give a quite-isotropic radiation pattern. It is also shown that when a single-bay turnstile is placed above a square conducting plate, it gives an omni-directional radiation pattern of either balloon-like or conical shape according to its height above the square plate. An integral equation method employing a Galerkin's technique is applied to get the input impedance and power gain and to investigate the polarization characteristics of the antenna. A wire-grid model is used to represent the square conducting plate above which the antenna is placed. The validity of the wire-grid model is investigated and the accuracy of the obtained results regarding the current distribution on the square plate is realized when compared with other published results based on a real surface model of the square plate. The frequency response of the input impedance and the VSWR of the antenna in free space as well as mat when it is placed above a square conducting plate are presented, and the bandwidth of the antenna is investigated.","PeriodicalId":194287,"journal":{"name":"Proceedings of the Twenty-First National Radio Science Conference, 2004. NRSC 2004.","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133092826","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}
Pub Date : 2004-03-16DOI: 10.1109/NRSC.2004.239893
S.A. Ibrahim, K. Hussein, A. A. Elnady
This paper introduces a detailed proposed design for a traveling-wave z-cut LiNbO/sub 3/ electrooptic modulator employing the idea of ridge structure using full wave analysis by applying the finite difference time domain (FDTD) method. Practical considerations are accounted for including substrate anisotropy, conductor finite conductivity and finite thickness of conducting electrodes. The effects of important design parameters on modulator performance are also highlighted, and a clear model for optical response is presented taking different mismatch conditions into consideration.
{"title":"Analysis and design of LiNbO/sub 3/ traveling-wave electrooptic modulator using FDTD","authors":"S.A. Ibrahim, K. Hussein, A. A. Elnady","doi":"10.1109/NRSC.2004.239893","DOIUrl":"https://doi.org/10.1109/NRSC.2004.239893","url":null,"abstract":"This paper introduces a detailed proposed design for a traveling-wave z-cut LiNbO/sub 3/ electrooptic modulator employing the idea of ridge structure using full wave analysis by applying the finite difference time domain (FDTD) method. Practical considerations are accounted for including substrate anisotropy, conductor finite conductivity and finite thickness of conducting electrodes. The effects of important design parameters on modulator performance are also highlighted, and a clear model for optical response is presented taking different mismatch conditions into consideration.","PeriodicalId":194287,"journal":{"name":"Proceedings of the Twenty-First National Radio Science Conference, 2004. NRSC 2004.","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126007516","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}
Pub Date : 2004-03-16DOI: 10.1109/NRSC.2004.239778
J. Halim, H. El-Hennawy
In this paper, an advanced multicarrier transmit diversity scheme is presented for code division multiple access (CDMA) technique. The proposed system is applied for the reverse link in case of a slowly-varying multipath Rayleigh fading channel. It combines both multicarrier spread spectrum CDMA (MC-SS-CDMA) scheme and delay transmit diversity (DTD) scheme. So, it is called "MC-SS-CDMA/DTD" system. Moreover, it exploits the RAKE receiver to retrieve the multipath components of the channel and achieve the multipath diversity gain in addition to both the transmit diversity gain and the frequency diversity gain. Also, this paper examines the proposed system for both urban environment and suburban environment and it compares the results of both environments together using a computer simulation. As will be shown, the proposed system can achieve a spectral efficiency and much better performance than that obtained in both MC-SS-CDMA system without transmit diversity and DTD system. Besides, the system performance in case of urban areas is better than that in case of suburban areas.
{"title":"Performance of multicarrier spread spectrum CDMA system with transmit diversity","authors":"J. Halim, H. El-Hennawy","doi":"10.1109/NRSC.2004.239778","DOIUrl":"https://doi.org/10.1109/NRSC.2004.239778","url":null,"abstract":"In this paper, an advanced multicarrier transmit diversity scheme is presented for code division multiple access (CDMA) technique. The proposed system is applied for the reverse link in case of a slowly-varying multipath Rayleigh fading channel. It combines both multicarrier spread spectrum CDMA (MC-SS-CDMA) scheme and delay transmit diversity (DTD) scheme. So, it is called \"MC-SS-CDMA/DTD\" system. Moreover, it exploits the RAKE receiver to retrieve the multipath components of the channel and achieve the multipath diversity gain in addition to both the transmit diversity gain and the frequency diversity gain. Also, this paper examines the proposed system for both urban environment and suburban environment and it compares the results of both environments together using a computer simulation. As will be shown, the proposed system can achieve a spectral efficiency and much better performance than that obtained in both MC-SS-CDMA system without transmit diversity and DTD system. Besides, the system performance in case of urban areas is better than that in case of suburban areas.","PeriodicalId":194287,"journal":{"name":"Proceedings of the Twenty-First National Radio Science Conference, 2004. NRSC 2004.","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131946411","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}
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