あらまし ネットワークのトラヒック量の増大に伴い,ネットワークの消費電力量が急増し,消費電力の削減 が急務となっている.また,ネットワークのリソースを有効に活用するために多対多接続サービス実現への要求 が増加している.本論文では,ネットワーク中のトラヒックを特定リンクに集約することで,空となった未使用 リンクをスリープ状態にし,ネットワーク全体の消費電力を削減する MiDORi ネットワーク技術における多対 多対応ルーチング手法として SuperPosed Minimum Spanning Tree (SPMST)アルゴリズムを提案する.提案 アルゴリズムは,多対多接続 MiDORi ネットワークにおける要求条件である,高い省電力性実現,20 秒以内で の 100 ノード以上かつ,1000 マルチキャストグループ以上対応の計算実行を満たす.計算機シミュレーション により,提案するアルゴリズムの省電力性・計算時間・マルチキャストグループ収容数の有効性を示すとともに, MiDORi ネットワークのプロトタイプシステムにおける提案アルゴリズムの有効性を検証した. キーワード 省電力ネットワーク,ルーチング,MP2MP,P2MP,マルチキャスト,GMPLS
Recently, many model-based decomposition algorithms, which are based on several scattering models, have been proposed to extract physical parameters of the Earth's surface [1]-[4]. Those algorithms decompose the received power into several scattering components, and some assumptions are necessary to find the scattering contribution. By the assumption(s) and scattering models in a used algorithm, decomposed scattering power of each component becomes often different with each other. Therefore, it is difficult to judge which algorithm is the best for a certain observation area. It can be useful to compare the algorithms and to clarify which one is suitable to detect a particular scattering mechanism. As a first step of the research, we compared several model-based polarimetric decomposition algorithms qualitatively from a viewpoint of “a visual difference in decomposition images”, “negative power”, and “ratio of scattering power”. In this paper, forested and urban area are selected for discussion.
We propose a evaluation method for electromagnetic shielding performance using an optical fiber link system with broadband antennas that consists of a transmitting optical fiber link system, receiving optical fiber link system, two broadband bi-corn antennas and a vector network analyzer. Our proposed method is based on a time domain analysis and a time-frequency analysis using short time Fourier transform. The proposed method eliminates the undesired waves from measured wave by using a time-domain technology and time-frequency analysis. It is proved that our proposed method can be used to evaluate the shielding effect for thin film type shielding sheet in the frequency range from 300 MHz to 6 GHz.
We examined optical fibers suitable for avoiding such problems as the fiber fuse phenomenon and failures at bends with a high power input. We found that the threshold power for fiber fuse propagation in photonic crystal fiber (PCF) and hole-assisted fiber (HAF) can exceed 18 W, which is more than 10 times that in conventional single-mode fiber (SMF). We considered this high threshold power in PCF and HAF to be caused by a jet of high temperature fluid penetrating the air holes. We showed examples of two kinds of failures at bends in conventional SMF when the input power was 9 W. We also observed the generation of a fiber fuse under a condition that caused a bend-loss induced failure. We showed that one solution for the failures at bends is to use optical fibers with a low bending loss such as PCF and HAF. Therefore, we consider PCF and HAF to be attractive solutions to the problems of the fiber fuse phenomenon and failures at bends with a high power input.
