• Title/Summary/Keyword: 해쉬 매핑

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A Geographic Distributed Hash Table for Virtual Geographic Routing in MANET (MANET에서 가상 위치 기반 라우팅을 위한 지역 분산 해쉬 테이블 적용 방법)

  • Ko, Seok-Kap;Kim, Young-Han
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.12
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    • pp.58-65
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    • 2008
  • This paper presents a new geographic distributed hash table (GDHT) for MANETs or Mesh networks, where virtual geographic protocol is used. In previous wort GDHT is applied to a network scenario based on two dimensional Cartesian coordinate system. Further, logical data space is supposed to be uniformly distributed. However, mobile node distribution in a network using virtual geographic routing is not matched to data distribution in GDHT. Therefore, if we apply previous GDHT to a virtual geographic routing network, lots of DHT data are probably located at boundary nodes of the network or specific nodes, resulting in long average-delay to discover resource (or service). Additionally, in BVR(Beacon Vector Routing) or LCR(Logical Coordinate Routing), because there is correlation between coordinate elements, we cannot use normal hash function. For this reason, we propose to use "geographic hash function" for GDHT that matches data distribution to node distribution and considers correlation between coordinate elements. We also show that the proposed scheme improves resource discovery efficiently.

Prediction of Dynamic Response of Structures Using CMAC (CMAC을 이용한 구조물의 동적응답 예측)

  • Kim, Dong Hyawn;Kim, Hyon Taek;Lee, In Won
    • Journal of Korean Society of Steel Construction
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    • v.12 no.5 s.48
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    • pp.605-615
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    • 2000
  • Cerebellar model articulation controller (CMAC) is introduced and used for the identification of structural dynamic model. CMAC has fascinating features in learning speed. It can learn structural response within a few seconds. Therefore it is suitable for the real time identification structures. Real time identification is required in the control of structure which may be damaged or undergo severe change in mechanical properties due to shrinkage or relaxation etc. In numerical examples, it is shown that CMAC trained with the dynamic response of three-story building can predict responses under not trained earthquakes with allowable error. Finally, CMAC has great potential in structural and control engineering.

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