http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Analysis of Packet Transmission Probability under Flooding Routing
홍정식,이창훈,이해상,Hong, Jung-Sik,Lie, Chang-Hoon,Lee, Hae-Sang Military Operations Research Society of Korea 1992 한국국방경영분석학회지 Vol.18 No.2
In this paper, the computational problems of packet transmission probability (PTP) in a computer communication network (CCN) under flooding routing are investigated. To avoid a congestion under this routing, two control methods are considerd, i. e., copy storage control and hop count control. Problems of PTP under flooding routings with these two control methods are respectively shown to be equivalent to those of source-to-terminal reliability(STR) with an exception for a case of hop count control where the hop count is less than the length of the longest path. For this exceptional case, an efficient computational algorithm for PTP is developed. This algorithm is proposed as an efficient tool for the determination of hop count which satisfies a given reliability constraint. A numerical example illustrates a proposed algorithm.
구훈영(Hoon Young Koo),김영복(Young Bok Kim),홍정식(Jung Sik Hong),이창훈(Chang Hoon Lie) 대한산업공학회 2007 대한산업공학회지 Vol.33 No.1
In a large complex system, maintenance priorities for the failed components are important to maintain the system reliability at required level. Commonly used methods of determining maintenance priorities are based on ranking the failed components by using reliability importance measures such as Birnbaum reliability importance, risk achievement worth and F-V importance, etc. In the preceding works, maintenance priorities for the failed components are determined by using such existing measures. In this study, a new method of determining maintenance priorities, which utilizes the joint reliability importance is proposed. By investigating the sign of the joint reliability importance, maintenance priorities obtained by the existing methods are adjusted to yield new revised priorities. The revised maintenance priorities are shown to be more effective than the existing ones from the standpoint of the speed of system recovery. Effectiveness of the proposed method is illustrated by numerical examples.
김영복(Young Bok Kim),이창훈(Chang Hoon Lie) 대한산업공학회 2007 대한산업공학회지 Vol.33 No.1
Estimating parameters of the lifetime distribution is investigated when field failure data are not completely reported. To take into account the reality and the accuracy of the estimates in such a case, the failure reporting probability is incorporated in estimating parameters. Firstly, method of maximum likelihood estimate (MLE) is used to estimate parameters of the lifetime distribution when failure reporting probability is known. Secondly, Expectation and Maximization (EM) algorithm is used to estimate the failure reporting probability and parameters of the lifetime distribution simultaneously when failure reporting probability is unknown. For both cases, procedures of estimation are illustrated for single Weibull distribution and mixed Weibull distribution. Simulation results show that MLE obtained by the proposed method is more accurate than the conventional MLE.
확산과 전이 모형을 적용한 WiBro와 HSDPA 서비스 수요 예측
장인갑 ( In Kap Chang ),홍정완 ( Jung Wan Hong ),홍정식 ( Jung Sik Hong ),박광만 ( Gwang Man Park ),이광희 ( Gwang Hee Lee ),이창훈 ( Chang Hoon Lie ) LGCNS 엔트루정보기술연구소 2008 Entrue Journal of Information Technology Vol.7 No.1
WiBro와 HSDPA는 초고속의 무선 인터넷 서비스를 안정적으로 제공하는 것을 목표로 삼고 있으며, 이동통신 시장에서 매우 유사한 서비스를 제공하고 있음을 알 수 있다. 서비스 초기에는 HSDPA와 WiBro의 서비스 기술 한계로 인하여 보완 관계를 유지할 것으로 예상하지만, 관련 기술의 발전에 따라 잠재적으로 경쟁관계로 변화할 것이다. 따라서 기술 발전에 따라 WiBro와 HSDPA 서비스의 상호관계 변화를 고려한 수요 예측 모형의 개발이 필요하다. 이에 본 연구에서는 기술적 진보에 따른 이동통신 서비스들 간의 상호관계 변화를 고려하여 이동통신 시장에서 WiBro와 HSDPA의 보완 및 경쟁 관계, 그리고 시장 잠식 효과를 반영할 수 있는 새로운 수요 예측 모형을 제안한다. 수요 예측 모형은 확산 모형과 전이 모형을 혼합하여 제안하였으며, 일반인과 전문가 설문조사 방법을 이용하여 모형에 필요한 모수들을 추정하고 제안한 모형을 적용하여 WiBro와 HSDPA의 수요를 예측하였다. WiBro and HSDPA aim to provide wireless broadband internet service stably and it is well known that they provide similar services in telecommunication markets. WiBro and HSDPA are expected to be complementary due to the limit of technology in the early stage of service, but the relationship of them becomes competitive as the related technology develops. Therefore, the development of demand forecasting model considering the change of mutual relationship between WiBro and HSDPA is necessary. In this paper, we propose a novel demand forecasting model which reflects complementary and competitive relationship between WiBro and HSDPA in telecommunication markets according to the advance of the related technology. The proposed model consists of diffusion and transition model and the demand forecasting of WiBro and HSDPA is predicted by using the parameters estimated from the survey results.