2011 XXXth URSI General Assembly and Scientific Symposium最新文献

{"title":"Spatial and temporal patterns in lightning discharges as a proxy of thunderstorm characteristics","authors":"M. Cohen, F. Zoghzoghy, R. Said, U. Inan","doi":"10.1109/URSIGASS.2011.6050742","DOIUrl":"https://doi.org/10.1109/URSIGASS.2011.6050742","url":null,"abstract":"Lightning is nature's way of destroying electrical buildup in thunderclouds. Thus, the pattern of lightning activity is inherently a proxy measure of the timescales for charge separation and the lateral extent of the charge reunification in a flash. Using data from lightning stroke geolocation networks such as NLDN and GLD360, we deduce statistically the charge buildup time by observing the suppression of the probability of two nearby flashes (an effect which fades away). We characterize this suppression effect for different storms, and as a function of storm phase and lightning parameters such as peak current and polarity.","PeriodicalId":325870,"journal":{"name":"2011 XXXth URSI General Assembly and Scientific Symposium","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129901982","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":"Single and joint statistics of ducting layer parameters determined from vertical profiles of atmospheric refractivity","authors":"M. Grábner, V. Kvicera, P. Pechac, O. Jicha","doi":"10.1109/URSIGASS.2011.6050869","DOIUrl":"https://doi.org/10.1109/URSIGASS.2011.6050869","url":null,"abstract":"Vertical profiles of atmospheric refractivity measured on 150 m mast are fitted with a modified Webster duct model. Time series of duct model parameters are obtained with one minute resolution. Empirical single and joint statistics of duct model parameters are determined from 7 month data. Interrelations between the duct parameters are discussed.","PeriodicalId":325870,"journal":{"name":"2011 XXXth URSI General Assembly and Scientific Symposium","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126684205","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 the links between peak to average power ratio for conventional RF power amplifiers and peak to average duration ratio for switching mode power amplifiers","authors":"G. Baudoin, A. Diet, M. Villegas","doi":"10.1109/URSIGASS.2011.6050515","DOIUrl":"https://doi.org/10.1109/URSIGASS.2011.6050515","url":null,"abstract":"For conventional RF power amplifier (PA), the power efficiency depends on the peak to average power ratio (PAPR) of the input signal, or more precisely on the statistical distribution of the input signal amplitude. In this paper we show that, in a similar way, the power efficiency of switching mode PA driven by ΣΔ or PWM signals depends on the statistical distribution of input signal the states and on a parameter equal to the Peak to Average Duration Ratio. This parameter is related to the PAPR in a way depending on the type of encoding of PA input signals.","PeriodicalId":325870,"journal":{"name":"2011 XXXth URSI General Assembly and Scientific Symposium","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126699322","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":"From near-field to far-field: Radiative coupling of particle plasmon resonances in three-dimensional geometries","authors":"R. Taubert, H. Giessen","doi":"10.1109/URSIGASS.2011.6050636","DOIUrl":"https://doi.org/10.1109/URSIGASS.2011.6050636","url":null,"abstract":"We demonstrate superradiant-like effects in a three-dimensional arrangement of particle plasmonic oscillators at Bragg distance. In a Bragg-stacked multilayer structure we observe the formation of a very broad photonic band gap that spans almost one octave in the optical frequency range.","PeriodicalId":325870,"journal":{"name":"2011 XXXth URSI General Assembly and Scientific Symposium","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126845447","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":"Early warning for volcanic activity investigated from the 2008 Chaiten eruption based on long-term observation by microwave radiometer","authors":"T. Maeda, T. Takano","doi":"10.1109/URSIGASS.2011.6050851","DOIUrl":"https://doi.org/10.1109/URSIGASS.2011.6050851","url":null,"abstract":"A microwave radiometer can observe thermal emission from the ground with less contamination by clouds than an infrared radiometer. However, because its spatial resolution is large, if an analysis method to compensate the disadvantage is developed, it should be more suitable to issue an alert for a volcanic activity in the early stage before an eruption. We have investigated an analysis method to detect local changes from the data of a satellite-borne microwave radiometer. We then applied this method for the Chaiten volcano in Chile, which was severely erupted in 2008. In this paper, the analysis results are presented.","PeriodicalId":325870,"journal":{"name":"2011 XXXth URSI General Assembly and Scientific Symposium","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126989015","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":"Wave excitation in the lunar wake associated with solar-wind proton entry","authors":"M. Nishino, Yoshifumi Saito, Y. Kasahara, Y. Omura, K. Hashimoto, T. Ono, H. Tsunakawa, F. Takahashi, M. Fujimoto","doi":"10.1109/URSIGASS.2011.6051091","DOIUrl":"https://doi.org/10.1109/URSIGASS.2011.6051091","url":null,"abstract":"The near-Moon space environment is characterized by formation of a plasma cavity region on the night side along the solar wind (SW) flow, which is called the lunar wake. Because the Moon obstructs the SW plasma flow, the wake region is much more tenuous than the ambient SW region. The plasma environment of the lunar wake has been considered as follows; Because high energy SW electrons can easily access the night side region while SW protons cannot, the wake region should be negatively charged. The electron-rich status of the lunar wake yields ambipolar (inward) electric field at the wake boundary where SW protons gradually come to the wake center along the interplanetary magnetic field (IMF) in the distant wake. Meanwhile, it has been reported that the SW entry into the distant wake gives rise to plasma waves. Broadband electrostatic noise (BEN) was detected by the Wind spacecraft in the distant wake (∼10,000 km from the Moon). The excitation of the BEN was attributed to ion two-stream instability owing to the SW proton beams that were accelerated/decelerated into the wake by the ambipolar electric fields. It was also attributed to electron two-stream instability that is expected to occur around the wake boundary region. However, such instabilities were not anticipated to occur in the near-Moon wake (say, ∼100 km altitude), because it has been believed that a major part of the SW particles cannot access the deepest wake so that any plasma effects would be inoperative there. Recently, a Japanese lunar orbiter SELENE (Kaguya) performed comprehensive measurements of the plasma and electromagnetic environment around the Moon at ∼100 km altitude. Concerning the night-side region, two mechanisms of SW proton entry into the near-Moon wake were found. One of them, the type-II entry, which becomes evident when the non-radial IMF component is dominant, is closely related to ‘self-pickup’ process of protons that were once scattered on the lunar dayside surface or magnetically reflected around the magnetic anomalies. This mechanism lets protons access the deepest region of the wake, namely, 150<SZA<180 deg at the 100 km altitude of the SELENE orbit. We found that typical type-II proton entry is accompanied by an enhancement of electron flux and BEN signals. The electron distribution was counter-streaming along the magnetic field, and their energy range was from several hundred eV to 1 keV. This energy is much higher than the typical energy of SW thermal electrons, which shows that acceleration operates as they are attracted from the SW to maintain the quasi-neutrality. Both ends of the magnetic field at the SELENE location were connected to the SW region, which is advantageous to the absorption of SW electrons from both ends into the PGR. The counter-streaming electrons give rise to two-stream instability that results in the excitation of electrostatic solitary waves (ESWs) in the PGR. We also estimate the positive superabundance in the PGR of the deepest wa","PeriodicalId":325870,"journal":{"name":"2011 XXXth URSI General Assembly and Scientific Symposium","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129185347","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":"White spaces communications in Europe","authors":"A. Morgado, N. Carvalho","doi":"10.1109/URSIGASS.2011.6050509","DOIUrl":"https://doi.org/10.1109/URSIGASS.2011.6050509","url":null,"abstract":"Cognitive Radio Communications and the switch off of analog TV in Europe is creating a strong and viable solution for testing new approaches to the implementation of Cognitive Radios in an effective way. In this paper the concept of White Spaces and specially the approaches that are thought to be developed in Europe will be studied and analyzed. It is expected that this work will be the basis for more focus on the white space communication protocols.","PeriodicalId":325870,"journal":{"name":"2011 XXXth URSI General Assembly and Scientific Symposium","volume":"714 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123843708","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":"People and planes: Development of broadband EMC models of biological materials in aircraft","authors":"M. Robinson, I. Flintoft, G. Melia","doi":"10.1109/URSIGASS.2011.6051356","DOIUrl":"https://doi.org/10.1109/URSIGASS.2011.6051356","url":null,"abstract":"At microwave frequencies, an aircraft can be modelled as a multi-mode, reverberant EM environment. The presence of people on board will damp its resonances, thus lowering their Q-factors and increasing the propagation loss between two points. The relevant parameter is the mean absorption cross section of the body, which is of the order of one sixth of body surface area. For EM simulations of aircraft it is necessary to develop broadband numerical phantoms to represent the people on the aircraft. These should be at an appropriate level of detail somewhere between millimetre-resolution dosimetry phantoms and homogenous dielectric spheres.","PeriodicalId":325870,"journal":{"name":"2011 XXXth URSI General Assembly and Scientific Symposium","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123978811","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":"Equivalent circuit synthesis for microstrip structures design and optimisation","authors":"A. Gorbunova, Y. Kuznetsov","doi":"10.1109/URSIGASS.2011.6050630","DOIUrl":"https://doi.org/10.1109/URSIGASS.2011.6050630","url":null,"abstract":"The paper suggests network synthesis algorithm used limited band scattering parameters of microwave devices. The proposed approach is based on the simple description of the microwave structures using lumped element network. The submitted example of synthesis illustrates the microstrip filter design.","PeriodicalId":325870,"journal":{"name":"2011 XXXth URSI General Assembly and Scientific Symposium","volume":"571 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123142893","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":"Reflection on curved surfaces in a 2.5D ray-tracing method for electromagnetic waves exposure prediction in urban areas","authors":"N. Noé, F. Gaudaire","doi":"10.1109/URSIGASS.2011.6050798","DOIUrl":"https://doi.org/10.1109/URSIGASS.2011.6050798","url":null,"abstract":"Asymptotic methods are commonly used to predict exposure to electromagnetic waves in large environments such as urban areas. Specifically 2D beam-tracing is a very efficient solution in case of GIS 2.5D environments. Nevertheless taking into account reflection on curved vertical walls or curved ground in such methods is not straightforward. Indeed curved surfaces are mostly described as meshes and lead to artificial shadowing and inaccurate electric field estimation. We explain here how to avoid such problems without modifying existing geometry by using normal interpolation in a generalized beam-tracing technique, and present results for some real cases.","PeriodicalId":325870,"journal":{"name":"2011 XXXth URSI General Assembly and Scientific Symposium","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123193925","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}