VICO:網路視訊會議系統

The combination of the networks and multimedia has been a popular research subject in the recent year. This paper presents our approaches to developing a point-to-point video conference system, VICO, based on the personal computer environments. The compression techniques adopted in the VICO system is based on the Intel's DVI technology （ Digital Video Interactive ）.The network transmission is based on FDDI and Ethernet networks. A number of Windows programming techniques are adopted. In particular, Winsock API techniques are utilized for system development to increase the system portability. VICO system is designed to include a system kernel module and several other modules, each of which is developed for the corresponding functionality. The video and audio module and the network module are used to deliver the text, graphics, audio and video data. The file transfer module and the whiteboard module enables the copy-and-paste data to be transferred in between systems and application programs. A comprehensive user interface is provided by the user interface module allowing system menu to be operated through the push-down buttons, and network games can be played concurrently between the two ends. The performance of the VICO system is in a moderate level when using 30 frames per second with 256 × 240 resolutions for each frame in a FDDI network. The development of the VICO system has demonstrated that our approach is feasible to develop a point-to-point video conference system based on the personal computer environments.網路多媒體應用中，視訊會議系統的發展是近年來普遍的研究主題。本篇論文主 要論述在個人電腦上發展一套點對點的視訊會議系統 VICO 所使用的方法與技術。 VICO 利 用 Digital Video Interactive 即時影像壓縮技術。 系統以模組化方式發展並採用 Winsock 網路應用程式介面。系統主要是由一個系統核心單元和五個子系統所組成。視訊音 訊子系統、網路子系統提供視訊、音訊資料之傳送與顯示。檔案傳送子系統與電子白板子系 統促使雙方使用者能同時在線上討論問題並交換訊息。此外系統內剪貼功能，更可和其他的 應用軟體交換圖形、文字資料，以提昇視訊會議之效能。人機介面子系統則提供適合的介面 來操作所有的系統功能。 VICO 系統經測試結果顯示，在 FDDI 網路和 Ethernet 網路上， 以每秒 30 張圖框，解析度為 256 × 240 大小之視窗來播放視訊與音訊時，系統之整體操 作反應略嫌遲鈍。經分析影響系統效能之因素有三項，分別為受限於網路頻寬之不足；受到 即時壓縮卡之硬體限制；程式尚未最佳化。 本文之結論為利用 DVI 壓縮技術和適切的技術 、技巧， 可以在以 PC 為基礎之 FDDI 與 Ethernet 網路發展一套點對點的視訊會議系統 。 VICO 系統發展過程中之經驗、技術與技巧可供爾後發展多人視訊會議系統之參酌

Performance Assessment of Hybrid Data Fusion and Tracking Algorithms

This paper presents an overview on the performance of hybrid data fusion and tracking algorithms evaluated in the WHERE consortium. The focus is on small scale indoor scenarios with ultra wideband (UWB) complementing cellular communication systems, mid scale indoor scenarios with Wi-Fi aiding cellular communication systems, and large scale outdoor scenarios with global navigation satellite systems (GNSSs) aided by cellular communication systems. For the small scale indoor scenario with UWB, the accuracy can vary in time as a connectivity-dependent random process distributed over 3 orders of magnitude, from 100m in the worst situation down to 0.1m in the most favourable one. In the mid scale scenario, time difference of arrival (TDOA) measurements from a cellular network can give wide-area coverage with limited accuracy, whereas the received signal strength measurements of Wi-Fi hotspots give more accurate results if coverage is available. Finally, for large scale outdoor scenarios, cellular TDOA measurements can support GNSS especially in critical scenarios, where only a few satellites are visible. This is even the case when the overall accuracy of stand-alone cellular positioning is lower than that for GNSS positioning under optimum conditions

D2.1 Performance Assessment of Hybrid Data Fusion and Tracking Algorithms

This deliverable presents a first performance evaluation of hybrid data fusion and tracking algorithms. The focus is on small scale indoor scenarios with ultra wideband (UWB) complementing cellular communication systems, mid scale indoor scenario with WIFI aiding cellular communication systems, and large scale outdoor scenario with global navigation satellite systems (GNSSs) aided by cellular communication systems. For the small scale indoor scenario with UWB, the accuracy will vary in time as a random process distributed over 3 orders of magnitude, from 100m in the worst situation down to 0.1m in the most favourable one. In the mid scale scenario, time difference of arrival (TDOA) measurements from a cellular network can give wide-area coverage with limited accuracy, whereas the received signal strength measurements of WIFI hotspots give more accurate results if coverage is available. Finally, for large scale outdoor scenarios, cellular TDOA measurements can support GNSS especially in critical scenarios even if the overall accuracy of stand-alone cellular positioning is lower than for GNSS positioning under optimum conditions

Structural Stability

IASS-IACM 2008 Session: Structural Stability -- Session Organizer: Herbert MANG (Technical University of Vienna) -- Plenary Lecture: Abstract, Slides and Video: "Answers to three not quite straightforward questions in structural stability" by Andreas STEINBOECK, Gerhard HOEFINGER, Xin JIA, Herbert A. MANG (Technical University of Vienna) -- Keynote Lecture: "Limit-point and postbuckling behavior of steel trusses under thermal and mechanical loadings" by Yeong Bin YANG , T.J. LIN (National Taiwan University) -- "Modeling thin-walled cold-formed steel members and systems" by Benjamin W. SCHAFER , R. H. SANGREE, Cristopher MOEN, M. SEIF, Y. SHIFFERAW, V. ZEINODDINI, Z. J. LI, O. IUORIO, Y. GUAN (Johns Hopkins University) -- "Multi parametrical instability of straight bars" by Jan B. OBREBSKI (Warsaw University of Technology) -- "The effect of predetermined delaminations on buckling and post-buckling behavior of spatial composite timber beams and frames" by Miran SAJE , Urban RODMAN, Dejan ZUPAN, Igor PLANINC (University of Ljubljana) -- Keynote Lecture: "Buckling and sensitivity analysis of imperfect shells involving contact" by Karl SCHWEIZERHOF , Eduard EWERT (University of Karlsruhe) -- Keynote Lecture: "Determining the stability of tensegrities and generic global rigidity" by Robert CONNELLY (Cornell University) -- "Initial imperfection identification in shell buckling problems" by Christopher J. STULL , Christopher J. EARLS, Wilkins AQUINO (Cornell University) -- "Buckling phenomena, analysis and design of axially compressed cylindrical shells with co-existent external pressure" by Werner GUGGENBERGER , Medhanye B. TEKLEAB (TU Graz

2008 IASS-IACM: Plenary Lectures

IASS-IACM 2008 Plenary Lectures: (1)"Modeling of shells with three-dimensional finite elements" by Manfred BISCHOFF (University of Stuttgart), from the Session: 3D Modeling of Thin-Walled Structures (2)"Nanomechanical resonators and nanofluidic systems" by Harold G. CRAIGHEAD (Cornell University), from the Session: Nano- and Micro-scale Structures (3)"Analysis and design of materials and structures for attenuating vibration and acoustic response" by Gregory M. HULBERT (University of Michigan), from the Session: Dynamic Analysis of Spatial Structures (4)"Large shell structures for power generation technologies" by Wilfried B. KRATZIG (Ruhr-University Bochum), from the Session: Spanning Between Theory and Practice (5)"Answers to three not quite straightforward questions in structural stability" by Herbert A. MANG (Technical University of Vienna), from the Session: Structural Stability (6)"Computational morphogenesis: Its current state and possibility for the future" by Hiroshi OHMORI (Nagoya University), from the Session: Computational Morphogenesis (7)"Folding and deployment of stored-energy composite structures" by Sergio PELLEGRINO (California Institute of Technology), from the Session: Deployable Structures and Biological Morphology (8)"Rigid mechanics and its role in nonlinear structural analysis" by Yeong Bin YANG (National Taiwan University), from the Session: Innovative Analysis Topic