2009 International Conference on Space Science and Communication最新文献

Lightwave measurement and characterization in passive optical network (PON) 无源光网络(PON)中的光波测量与表征

2009 International Conference on Space Science and Communication Pub Date : 2009-12-15 DOI: 10.1109/ICONSPACE.2009.5352669

N. Chuan, M. Ab-Rahman

引用次数: 4

Dual band folded patch antenna for WLAN operation 用于WLAN操作的双波段折叠贴片天线

2009 International Conference on Space Science and Communication Pub Date : 2009-12-15 DOI: 10.1109/ICONSPACE.2009.5352660

M. Yunus, N. Misran, M. Islam

引用次数: 5

Analysis of concentric split ring square reflectarray element for bandwidth enhancement 用于增强带宽的同心分裂环方形反射单元分析

2009 International Conference on Space Science and Communication Pub Date : 2009-12-15 DOI: 10.1109/ICONSPACE.2009.5352670

S. H. Yusop, N. Misran, M. Islam, M. Ismail

{"title":"Analysis of concentric split ring square reflectarray element for bandwidth enhancement","authors":"S. H. Yusop, N. Misran, M. Islam, M. Ismail","doi":"10.1109/ICONSPACE.2009.5352670","DOIUrl":"https://doi.org/10.1109/ICONSPACE.2009.5352670","url":null,"abstract":"An analysis of phase variation and phase range of concentric split ring square element for broadband reflectarray antenna is presented in this paper. This element is the combination of a single square element and a ring element where the square element is the modification of the conventional annular ring element which instead of using annul as the hole, this new idea presents a square as the hole in the ring. This will varies the current distribution in the element which will then improves the performance of the bandwidth. The analysis and the design of this reflectarray element is presented based on variable size which operates at the first resonant frequency of 13.44 GHz and at the second resonant frequency of 18.36 GHz. The design procedure and critical parameters consist of phase range and phase slope (or variation) are also discussed. Modifying the current distribution of square ring element, leads to a less steep phase variation and also enhancement on the bandwidth performance (up to 67.6%). The practical phase range is achieved through the use of RF35 as the substrate with the dielectric constant of 3.54 and the thickness of 1.524 mm. CST Microstripes is used as the software tool to get the simulation results.","PeriodicalId":360685,"journal":{"name":"2009 International Conference on Space Science and Communication","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122191005","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: 7

Determination of optimized ionospheric layer for TEC measurement at equatorial region 赤道地区TEC测量最佳电离层的确定

2009 International Conference on Space Science and Communication Pub Date : 2009-12-15 DOI: 10.1109/ICONSPACE.2009.5352646

M. H. Jusoh, N. A. Aziz, N. Othman, M. A. Haron, H. Saad

{"title":"Determination of optimized ionospheric layer for TEC measurement at equatorial region","authors":"M. H. Jusoh, N. A. Aziz, N. Othman, M. A. Haron, H. Saad","doi":"10.1109/ICONSPACE.2009.5352646","DOIUrl":"https://doi.org/10.1109/ICONSPACE.2009.5352646","url":null,"abstract":"Ionosphere layer is very important to the communication system. In Malaysia the ionosphere layer is unique because the location is near the equator where it exposed more ultraviolet radiation (UV) compared to other region. This project focuses on the determination optimized ionospheric layers for TEC measurements at equatorial region. The main parameter in this project is Total Electron Content (TEC) with elevation angle of satellite between 50 to 85 degrees. Since these satellites are in different parts of the sky and the electron content in the ionosphere varies both spatially (track) and temporally (time), the Ionospheric Pierce Point (IPP) altitude plays an important role in converting the vertical TEC from the measured slant TEC. The TEC computed from the Global Positioning System (GPS) data for different altitudes ranging from 50 km to 750km. The data from GPS dual frequency which are in Receiver Independent Exchange Format (RINEX) are supplied by Department of Survey and Mapping Malaysia (JUPEM). The data taken from two different stations located at Universiti Sains Malaysia Pulau Pinang (USMP) and Universiti Teknologi Malaysia Johor (UTMJ). The results show a variation of TEC does not significantly changes when the elevation angle is greater than 50 degrees. Therefore, the IPP altitude of 450 km to 750 km may consider as effective ionospheric layer in the equatorial region.","PeriodicalId":360685,"journal":{"name":"2009 International Conference on Space Science and Communication","volume":"159 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120865826","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

Lithium-ion for Pico satellites power system 微型卫星动力系统用锂离子电池

2009 International Conference on Space Science and Communication Pub Date : 2009-12-15 DOI: 10.1109/ICONSPACE.2009.5352653

Z. Aziz, Mohd Amir Iskandar Mazlan, Kamal Irfan Ahmad Shakir, N. Hamzah, A. S. Arshad

引用次数: 1

On the interaction effects of ionospheric plasma with dipole magnetic field of the spectrometer AMS-02 moving onboard of international space station 国际空间站上移动的AMS-02光谱仪电离层等离子体与偶极磁场的相互作用

2009 International Conference on Space Science and Communication Pub Date : 2009-12-15 DOI: 10.1109/ICONSPACE.2009.5352662

Y. Zakharov, V. M. Antonov, E. Boyarintsev, K. V. Vchivkov, A. Melekhov, V. Posukh, I. Shaikhislamov, A. Ponomarenko, I. Veselovsky, A. Lukashenko

{"title":"On the interaction effects of ionospheric plasma with dipole magnetic field of the spectrometer AMS-02 moving onboard of international space station","authors":"Y. Zakharov, V. M. Antonov, E. Boyarintsev, K. V. Vchivkov, A. Melekhov, V. Posukh, I. Shaikhislamov, A. Ponomarenko, I. Veselovsky, A. Lukashenko","doi":"10.1109/ICONSPACE.2009.5352662","DOIUrl":"https://doi.org/10.1109/ICONSPACE.2009.5352662","url":null,"abstract":"When the large-scale spectrometer AMS-02 with the super-conductive coils will be installed at ISS, their residual magnetic field could be effective dipole-like obstacle to form a so called “Magnisphere” in front of AMS due to its interaction with the plasma of ionosphere under conditions of super-sonic, but sub-alfvenic ISS velocity. The boundary (between magnetic field and plasma, at distance RN ∼ 5÷8 m from AMS) of such “Magnisphere” or other mini-magnetospheres, could essentially disturb the whole plasma and electromagnetic environments of ISS due to various small- and large-scale plasma instabilities or waves generation. Therefore we discuss a relevant actual problem and specific features of “Magnisphere” formation, structure and dynamics under essentially non-MHD conditions of the interaction between a dipole and plasma flow, when its directed ion Larmor is in a few times larger than RN. Preliminary data of the laboratory and numerical simulations for such extremely non-MHD dipole-plasma interaction are presented.","PeriodicalId":360685,"journal":{"name":"2009 International Conference on Space Science and Communication","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126521122","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: 4

Comparison between the foF1 and foF2 critical freqeuncy in equatorial region of Malaysia 马来西亚赤道地区foF1和foF2临界频率的比较

2009 International Conference on Space Science and Communication Pub Date : 2009-12-15 DOI: 10.1109/ICONSPACE.2009.5352651

S. Abdullah, A. Zain

{"title":"Comparison between the foF1 and foF2 critical freqeuncy in equatorial region of Malaysia","authors":"S. Abdullah, A. Zain","doi":"10.1109/ICONSPACE.2009.5352651","DOIUrl":"https://doi.org/10.1109/ICONSPACE.2009.5352651","url":null,"abstract":"The ionosphere is the topside of the atmosphere that contains high concentration of ions and can reflect radio waves due to refraction. The ionospheric region of interest is located above the equatorial region at longitude 1° 52' and latitude 103° 48' (Parit Raja, Johor). The observations of the ionospheric critical frequency were made from 2005 to 2007. The critical frequency is determined by using the monthly median value for each day. Regression analysis was used on the theoretical and observed value. The observed value is obtained from ionogram measurements with five-minute intervals using logarithmic frequency steps from 1 Mhz to 20 Mhz. The sunspot number is used as a parameter to compare the values of critical frequency at high sunspot and low sunspot numbers for the day. The foF2 critical frequency for 2005, 2006 and 2007 show that the higher value is for 2005, 11 MHz while the critical frequency is much lower for 2006 and 2007, 9.7 MHz and 8.95 MHz. The correlation analysis was used to determine the relationship for the yearly value. The correlation was made using the median value of the foF2 critical frequency from 2005 until 2007. The regression and correlation analysis of the critical frequency was able to show the trend of the critical frequency for 2005, R2 = 0.031, 2006, R2 = 0.112 and 2007, R2 = 0.017.","PeriodicalId":360685,"journal":{"name":"2009 International Conference on Space Science and Communication","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130429075","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

Integrated adaptive approach for reliable multicast transmission over geostationary satellite networks 地球同步卫星网络可靠多播传输的集成自适应方法

2009 International Conference on Space Science and Communication Pub Date : 2009-12-15 DOI: 10.1109/ICONSPACE.2009.5352673

A. Sali, H. A. Karim, G. Acar, B. Evans

{"title":"Integrated adaptive approach for reliable multicast transmission over geostationary satellite networks","authors":"A. Sali, H. A. Karim, G. Acar, B. Evans","doi":"10.1109/ICONSPACE.2009.5352673","DOIUrl":"https://doi.org/10.1109/ICONSPACE.2009.5352673","url":null,"abstract":"Multiple retransmission passes, in order to ensure bit-perfect reliability in multicast transmission, results in lower resource utilization and higher session delay. Hence, an integrated adaptive transmission via the use of a cross-layer strategy is proposed in this paper in order to increase forward and return link resource utilization. Specifically, the integration of Channel State Information (CSI) collection policies in the uplink and Channel-Aware Scheduling (CAS) in the downlink is proposed in the face of fluctuating channel conditions observed by multicast terminals. The integration approach can be mathematically represented by suppression error due to the way CSI is collected and suppressed in the return link. Particularly, the suppression error occurs since only a subset of users update their CSI values at any CSI collection instant. In relation to the analytical representation of the suppression error, the performance parameters are then verified via simulation results. From the comparison, it was found that the simulation and analytical results approach agreement at large numbers of terminals. This observation suits the multicast transmission over satellite networks which expect large numbers of terminals over wide coverage.","PeriodicalId":360685,"journal":{"name":"2009 International Conference on Space Science and Communication","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125333967","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

The Hurst exponents of the geomagnetic horizontal component during quiet and active periods 平静期和活动期地磁水平分量的赫斯特指数

2009 International Conference on Space Science and Communication Pub Date : 2009-12-15 DOI: 10.1109/ICONSPACE.2009.5352642

N. S. A. Hamid, G. Gopir, M. Ismail, N. Misran, A. Hasbi, M. Usang, K. Yumoto

{"title":"The Hurst exponents of the geomagnetic horizontal component during quiet and active periods","authors":"N. S. A. Hamid, G. Gopir, M. Ismail, N. Misran, A. Hasbi, M. Usang, K. Yumoto","doi":"10.1109/ICONSPACE.2009.5352642","DOIUrl":"https://doi.org/10.1109/ICONSPACE.2009.5352642","url":null,"abstract":"The focus in this paper is mainly to characterize the fractal properties denoted by the Hurst exponent of geomagnetic field during quiet and active periods of geomagnetism activity. Analysis is made on the time series of the geomagnetic horizontal component data, H, which were acquired by the Magnetic Data Acquisition System (MAGDAS) developed by the Space Environment Research Center (SERC) of Kyushu University in Japan. The data set covers the quiet and active periods in August 2005 at the equatorial stations of Cebu and Davao in the Philippines. This month had very intense geomagnetic storm with the Dstmin, Kp and Ap indices for the quietest and active days of the month are −20 nT, 2, 6 and −216 nT, 9, 110 respectively. For both stations, the data sampling interval is 1 second for each time periods or one day giving a sample size of 86,400. Using the fast Fourier transform, the power law of the data time series was obtained in the shorter time periods of 10 minutes to 6 hours. This observed power spectrum law exhibit scaling with corresponding Hurst exponents of 0.3–0.5 for quiet periods and 0.5–0.7 for active periods for both stations. For comparison, other fractal techniques were performed which are rescaled range analysis (RS) and detrended fluctuation analysis (DFA) on the data set, and the same ranges of the Hurst exponents were obtained. The work also includes simulation of the similar sized data sets by generating the fractional Brownian motions (FBM) with the Hurst exponents of 0.3–0.7. Our results show that the H component at these equatorial stations is a fractal in nature and become more persistent during active periods of geomagnetism activity. Thus, the Hurst exponent could be used to characterize the geomagnetic time series during quiet and active periods.","PeriodicalId":360685,"journal":{"name":"2009 International Conference on Space Science and Communication","volume":"107 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127017545","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: 10

Plasma drift during periods of low geomagnetic activity at UTHM's Parit Raja station 在UTHM的Parit Raja站低地磁活动期间的等离子体漂移

2009 International Conference on Space Science and Communication Pub Date : 2009-12-15 DOI: 10.1109/ICONSPACE.2009.5352654

A. Z. Ahmad, A. Zain

引用次数: 1