• Title/Summary/Keyword: 잔류수명

Search Result 166, Processing Time 0.046 seconds

Design and Performance Evaluation of Maximum Remaining Energy Constrained Directed Diffusion Routing Algorithm for Wireless Sensor Networks (센서 네트워크를 위한 최대 잔류 에너지 제한 Directed Diffusion 라우팅 알고리즘의 설계 및 성능 분석)

  • Hwang, An-Kyu;Lee, Jae-Yong;Kim, Byung-Chul
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.30 no.11A
    • /
    • pp.995-1003
    • /
    • 2005
  • Since the sensor network nodes have a small size and limited battery power, there have been many studies for reducing their energy consumption. Each sensor node can show different energy usage according to the frequency of event sensing and data transmission, and thus they have different lifetime. So, some nodes may run out of energy that causes disconnection of paths and reduction of network lifetime. In this paper, we propose a new energy-efficient routing algorithm for sensor networks that selects a least energy-consuming path among the paths formed by node with highest remaining energy and provides long network lifetime and somewhat uniform energy consumption by nodes. Simulation results show that our algorithm extends the network lifetime and enhances the network reliability by maintaining relatively uniform remaining energy distribution among sensor nodes.

Structural Indentification:Analytical Aspects (구조 식별: 해석적 측면)

  • 김정태
    • Computational Structural Engineering
    • /
    • v.12 no.1
    • /
    • pp.95-114
    • /
    • 1999
  • 본 기사는 미국 토목학회(ASCE) 논문집 Journal of Structural Engineering의 1998년 7월호(Vol. 124, No. 7)에 게재된 Aktandhl 3인의 논문을 중심으로 관련된 논문들을 정리한 번역기사이다. 국내·외적으로 대형구조물의 손상도 검색, 노후화 진단, 잔류수명 추정 및 안전도 평가를 위해 구조식별(Structural Identification)기법을 응용하는 연구들이 활발하다. 본 논문은 구조식별에 대한 실험적-경험적인 접근법과 이론적 접근법을 함께 통합적으로 다루고 있는 논문으로서, 국내의 관련 연구자들과 현장의 기술자들의 구조식별기법 및 적용방법에 대한 이해를 돕기위해 선정되었다.

  • PDF

Microscopic Analysis of Effect of Shot Peening on Corrosion Fatigue Behavior of Aluminum Alloy (알루미늄합금 재료의 부식피로거동에 미치는 쇼트피닝 효과에 대한 미시적 분석)

  • Kim, Jong-Cheon;Cheong, Seong-Kyun
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.36 no.11
    • /
    • pp.1381-1389
    • /
    • 2012
  • The object of this study considers corrosion fatigue improvement of 7075-T6 aluminum by using shot peening treatment on 3.5% NaCl solution at room temperature. Aluminum alloy is generally used in aerospace structural components because of the light weight and high strength characteristics. Many studies have shown that an aluminum alloy can be approximately 50% lighter than other materials. Mostly, corrosion leads to earlier fatigue crack propagation under tensile conditions and severely reduces the life of structures. Therefore, the technique to improve material resistance to corrosion fatigue is required. Shot peening technology is widely used to improve fatigue life and other mechanical properties by induced compressive residual stress. Even the roughness of treated surface causes pitting corrosion, the compressive residual stress, which is induced under the surface layer of material by shot peening, suppresses the corrosion and increases the corrosion resistance. The experimental results for shot peened specimens were compared with previous work for non treated aluminum alloy. The results show that the shot peening treatment affects the corrosion fatigue improvement of aluminum alloys and the induced compressive residual stress by shot peening treatment improves the resistance to corrosion fatigue.

A Routing Protocol for Network Lifetime Extension in MANET (MANET에서 네트워크 수명 연장을 위한 라우팅 프로토콜)

  • Kim, Kyoung-Ja;Han, Sang-Hoon;Koo, Hyun-Woo
    • The Journal of the Korea Contents Association
    • /
    • v.10 no.2
    • /
    • pp.120-129
    • /
    • 2010
  • MANET(Mobile Ad Hoc NETwork) is a collection of mobile nodes that are free to move and organize themselves in an arbitrary manner without any fixed infrastructures. These mobile nodes are connected by wireless links and act as routers for all other nodes in the network. As a router each node in MANET consumes its batteries when forwarding a message, and the selection of the best path to minimize the total power needed to route packets is needed to maximize the lifetime of all nodes. In this paper, we propose a routing protocol considering the remaining battery capacity of nodes in the routing paths. The proposed scheme prevents the battery of each node from being overused and increases the lifetime of the network.

The Study about the Fatigue Strength Improvement Mechanism by the Processing of Fillet Welded Joint (필렛용접이음부의 후처리에 따른 피로강도 향상 메커니즘의 연구)

  • Lim, Cheong Kweon;Park, Moon Ho;Chang, Chun Ho
    • Journal of Korean Society of Steel Construction
    • /
    • v.11 no.3 s.40
    • /
    • pp.319-327
    • /
    • 1999
  • This study makes mechanism of the fatigue strength improvement by the processing of weld toe clear for the vertical cross rib specimens which was made fillet weld joint, also it proposes to the appropriate later processing. As a result of tension fatigue test, the fatigue strength improvement could have been seen in later processed specimens than as-weld specimens. Especially fatigue crack initial life $N_c$ increased in specimens which processed grinder after hammer-peening. Also, fatigue crack propagation life $N_p$ improved more in hammer-peening specimens than as-weld or TIG specimens. It thinks that $N_c$ is because of the geometrical shape of weld toe, i.e. the relaxation of the stress concentration and also that $N_p$ is because the big compression residual stress which was introduced in the surface by hammer-peening is restraining the propagation of fatigue crack.

  • PDF

The Influence of Machinability on Tool life of the ADI Materials in Drilling (ADI재료의 드릴가공시 절삭특성이 공구수명에 미치는 영향)

  • 반재삼
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1996.04a
    • /
    • pp.92-96
    • /
    • 1996
  • 최근 유용한 신소재로많은 광심을 보이고 있는 오스템퍼처리 구상흑연 주철(Austempered Ductile Cast Iron 이하 ADI라 한다) 은 기지조직이 베이나이트와 잔류 오스테나이트로 구성되어있기 때문에 같은 화학 조성을 갖는 일반 구상 흑연 주철에 비하여 연성 및 연성의 감소가 없이 2배 정도의 강도를 증가 시킬수 있기 때문에 자동차, 선박 부품 및 각종 기계부품에 적용시키기 위한 많은 연구가 진행되고 있다. 본 연구에서는 서로 재질의 성분이 다른 고속도강 드릴인 소경드릴을 이용하여 ADI재료를 보통(비관통)이송 및 단계이송 절삭가공시 발생되는 공구의 마멸량과 표면조도와의 관계, 절삭력의 변화에 따른 공구마멸과 공구수명과의 관계를 실험적으로 규명하여 ADI재료 의 보통 및 단계이송절삭시 공구수명에 미치는 제반 절삭특성의 영향에 관해 고찰 하고자 한다.

  • PDF