• Title/Summary/Keyword: 효율성 향상

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A Study of MAC Protocol for effective channel usage in Wireless Sensor Networks (무선 센서 네트워크에서 효율적인 채널 사용을 위한 MAC 프로토콜에 관한 연구)

  • Choi, Ji-Hyoung;Kim, Dong-Il
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2007.06a
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    • pp.371-374
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    • 2007
  • The effective channel usage is important for delivering a large number of packets in a short time, and it enhances channel utilization in sensor networks. Channel utilization is a good metric to illustrate MAC protocol efficiency. This paper presents the MAC(Media Access Control) Protocol that combines the advantages of B-MAC(Berkeley-MAC) and TDMA(Time Division Multiple Access) to obtain high channel utilization. Basically, Using the backoff, CCA(Clear Channel Assessment) and LPL(Low Power Listen) mechanisms reduce collision and energy consumption, this protocol makes at the same time transmission method different depending on contention state and obtains high channel utilization. Through the simulation, this paper shows enhanced performance comparing with existing MAC Protocols.

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An Energy Efficient Cluster-Based Local Multi-hop Routing Protocol for Wireless Sensor Networks (무선 센서 네트워크를 위한 에너지 효율적인 클러스터 기반 지역 멀티홉 라우팅 프로토콜)

  • Kim, Kyung-Tae;Youn, Hee-Yong
    • The KIPS Transactions:PartC
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    • v.16C no.4
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    • pp.495-504
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    • 2009
  • Wireless sensor networks (WSN) consisting of a largenumber of sensors aims to gather data in a variety of environments and is beingused and applied in many different fields. The sensor nodes composing a sensornetwork operate on battery of limited power and as a result, high energyefficiency and long network lifetime are major goals of research in the WSN. Inthis paper we propose a novel cluster-based local multi-hop routing protocolthat enhances the overall energy efficiency and guarantees reliability in thesystem. The proposed protocol minimizes energy consumption for datatransmission among sensor nodes by forming a multi-hop in the cluster.Moreover, through local cluster head rotation scheme, it efficiently manageswaste of energy caused by frequent formation of clusters which was an issue inthe existing methods. Simulation results show that our scheme enhances energyefficiency and ensure longer network time in the sensor network as comparedwith existing schemes such as LEACH, LEACH-C and PEACH.

A Study on Efficient Entity Bean Assembly Methodology Using EJB Dual Persistent Entity Bean Patterns (EJB Dual Persistent 엔터티 빈 패턴을 이용한 효율적인 엔터티 빈 조립방법에 관한 연구)

  • 이창수;이돈양;송영재
    • Proceedings of the Korean Information Science Society Conference
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    • 2002.10d
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    • pp.43-45
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    • 2002
  • EJB는 컴포넌트 기반 개발(CBD)을 지원하는 컴포넌트 모델중의 하나이며 최근 특어 EJB를 이용한 활발한 어플리케이션이나 시스템 구축이 이루어지고 있다. 최근 증가하고 있는 EJB 컴포넌트들을 효율적으로 재사용 하기 위한 필요성이 대두되고 있다. 본 논문에서는 EJB 컴포넌트 타입 중 엔터티 빈들 간의 조립을 목적으로 Dual Persistent 엔터티 빈 괘턴을 이용한 효율적인 엔터티 빈 조립 방법을 제안하여 기존에 영속성에 대한 종속성이 강해 재사용이 쉽지 않던 BMP 엔터티 빈을 영속성이 독립적인 CMP 엔터티 빈으로 변환해 재사용 향상된 조립을 한다.

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Enhancement of Computational Efficiency for Type-1 Fuzzy Logic Controller Using Rule Selection Method (Rule 선택 기법을 사용한 Type-1 Fuzzy Logic Controller의 연산 효율성 향상)

  • Joh, Jung-Woo;Park, Gwi-Tae
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.1879_1880
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    • 2009
  • 본 논문에서는 제어상황에 따라 Type-1 Fuzzy Logic Controller가 선택적으로 rule을 사용하도록 rule 선택 알고리즘을 제안 한다. 그리고 이를 통해 연산 효율성을 높이는 방법에 관해 논한다. Type-1 Fuzzy Logic Controller는 기존의 제어기에 비해 설계하기 쉽고 성능이 더 뛰어나다. 그러나 제어 변수가 많아질수록 rule의 개수가 늘어나 연산량이 증가하게 된다. 연산량이 많아지면 고성능의 컴퓨터에서는 실시간 연산에 문제가 없으나 산업용 micro controller에서는 실시간 연산을 구현하는데 한계가 발생한다. 본 논문에서는 Type-1 Fuzzy Logic System의 논리구조에 근거하여 Type-1 Fuzzy Logic Controller의 연산량을 감소시킬 수 있는 알고리즘을 제안한다. 제안한 알고리즘은 제어상황에 따라 필요한 rule들만 선택적으로 제어값 도출을 위한 연산에 관여하도록 한다. Matlab 시뮬레이션을 통해 제안한 알고리즘의 유용성과 연산량을 실험하였다. 실험대상은 2륜 이동로봇으로 하였고 step 응답과 전/후진 시 결과를 관찰하였다. 실험 결과 제안한 알고리즘이 기존의 Type-1 Fuzzy Logic Controller에 비해 제어상황에 따라 필요한 rule들만 선택적으로 사용하는 것을 확인하였다. 결과적으로 연산 효율성이 향상되었다.

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Measurement of Multi Conflict Avoidance for Free flight Efficiency (자유비행 다중 충돌회피 효율성 측정 연구)

  • Lee, Dae-Yong;Kang, Ja-Young
    • Journal of Advanced Navigation Technology
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    • v.16 no.2
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    • pp.197-203
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    • 2012
  • In this paper, study the substantial issues which occurs upon free flight environment by performing separation assurance under multiple conflict(over 3 Aircraft), recovery en route under the terms of time constrains and fixed way point after the conflict avoidance, correlations between conflict detection distance and separation assurance by utilizing Autonomous flight algorithm. Result of this experiment demonstrates that the extension of detection distance is advantageous to solution of separation assurance and enhancing of flight efficiency, choose to maneuver by applying time constrain terms and fixed way point according to the situation of conflict prediction in case of recovery maneuver after the conflict avoidance. And separation assurance can be solved by applying 2 degrees or more of bank angle. When choosing the optimal bank angle could be drastically improved flight efficiency.

Efficiency Analysis for Korean Trucking Companies based on the Data Envelopment Ananlysis(DEA) (DEA 모형을 이용한 국내 화물자동차운송업체의 상대적 효율성 분석)

  • Choi, Jong-Yeol;Park, Je-Hun
    • The Journal of the Korea Contents Association
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    • v.11 no.1
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    • pp.317-328
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    • 2011
  • Logistic system and methods of the transportation have been changed rapidly by the variety of the logistics environment. It is necessary to analyze the efficiency of Korean trucking companies for enhancing the competitive power and operating. This paper will describe the analysis of the efficiency of the trucking companies with DEA models. By the CCR and the BCC models, which are in parts of DEA model, the efficiency and RTS(Return To Scale) of forty two selected trucking companies were studied. It was also analyzed how the study the input-output variables were effected. And then, some of the forty two trucking companies were shown as the benchmark. As the result of analysis on the two models, seven companies won the score '1' on CCR model and seventeen companies on BCC model. Moreover, this study showed that reducing the total asset out of input variables, and raising the sales profit out of the output variables played a main role to increase the efficiency of the trucking companies highly.

A Study on the Application of Transfer Equipment Pooling Systems for Enhancing Productivity at Container Terminals (컨테이너터미널에서 생산성 향상을 위한 이송장비 풀링시스템 적용방안에 관한 연구)

  • Cha, Sang-Hyun;Noh, Chang-Kyun
    • Journal of Navigation and Port Research
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    • v.38 no.4
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    • pp.399-407
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    • 2014
  • Due to the increase of container terminals, as the volume of terminals become distributed, the competition of preserving existing volume and inviting new volume are becoming fierce, and various ways for processing terminal volume and inviting volume are being sought. Container terminal efforts to maximize efficiency in order to improve the volume handling capability and productivity by both expansion of the latest equipment and development of the latest terminal system. There are a variety of factors that influence the improvement of productivity at container terminals. Among them, in the case of yard transfer equipment, if it were to convert from the method of a Yard Tractor(YT) being fixed allocated to a certain Gantry Cranes(GC) to a Pooling System that processes in a method that properly distributes and allocates a Yard Tractor(YT) to multiple Gantry Cranes(GC), the terminal productivity and the fusibility of YT may be increased. The KPI which is an indicator for the productivity at container terminals is GC productivity and since GC productivity cannot exceed the speed of physical GC operations, a Pooling System is applied to increase productivity which its meaning and effect is massive. Here in the Report, we produce the Pooling Algorithm system to improve the efficiency of the transported equipments in container terminal which is actually applying for this method and have compared Non pooling system with Pooling system in the fields. By introducing a transfer equipment pooling system and enhancing the productivity compared to other terminals, it may become an essential factor for increasing the continuous service quality and profitability in terms of terminal business.

우리나라 컨테이너터미널 운영사의 경영효율성 평가에 관한 연구

  • Gang, Hyeon-Gu;Ryu, Dong-Geun;Son, Bo-Ra;Seo, Yeong-Jun
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2011.06a
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    • pp.422-424
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    • 2011
  • 오늘날과 같이 급속히 변화하는 기업경영 환경에서 조직이 생존하고 번영하기 위해 기업의 경영 성과를 향상시켜야 하고 이를 위해서는 생산성 또는 효율성을 꾸준히 평가할 필요가 있다. 본 연구는 평가대상의 상대적 효율성을 측정하기 위해 개발된 DEA(Data Envelopment Analysis) 방법론을 이용하여 국내 컨테이너터미널 운영사의 경영 효율성을 비교 분석함으로써 2007년부터 2009년까지의 터미널 운영사의 효율성 수준을 파악해 보았다. 연구결과 2007년부터 2009년까지 점차적으로 영업이익률이 줄어드는 현상이 나타나는데, 이것은 산출변수에는 큰 변화가 없는 반면 투입변수는 지속적으로 증가하고 있다는 것을 알 수 있다. 이것은 동 기간 사이에 컨테이너터미널 업체수는 증가하였음에도 불구하고 물동량의 증가가 미미하여, 물동량 확보를 위한 터미널 업체들간의 경쟁이 치열해졌다는 것을 알 수 있다. 이러한 경쟁은 하역요율의 단가하락 문제를 발생시켰으며, 이로 인해 업체들의 경영악화가 가속되었다는 것을 의미한다. 본 연구 결과는 물동량 변화에 따른 투입변수의 최적화를 통해 컨테이너터미널 운영사의 경영효율성을 제고하는데 기여 할 것으로 판단된다.

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