• 품질경영학회지
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• 제27권2호
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• pp.251-262
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• 1999

In the automated manufacturing systems, the problem regarding how to make production activities flexible is even more important and critical than that regarding how to product large quantities, and the more flexible, if possible, the manufacturing system is, the more competitiveness and profitable factors it gets. This research, therefore, concentrated on establishing the flexibility and evaluating performance on the manufacturing system, operational flexibility is considered because of enabling the manufacturing system to get both the improvement of production rate and the adaptive ability of environment changes. For it, we used the analytical tool, GSPNs, which is a kind of timed Petri-Nets. GSPNs is competent enough to consider practical situations just like operation priorities, machine failure, randomness, concurrency and so on. Through the GSPNs analysis, it is confirmed that in the manufacturing system with operational flexibility is compatible with the traditional performances such as production rate or mean waiting time.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1946-1954
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• 2008

In urban railways operated by 10 cars or 8 cars per trainset, passengers split up and board a train. On-board passengers for each car are not aware of congestion level of other cars of the train. Passengers waiting at stations can not predict congestion rate of the car which they get on. Therefore, the number of passengers is not equally distributed. The cars with a relatively low congestion level and the ones with a high level coexist in the train. The objective of this paper is to enhance passenger convenience and improve train operational efficiency through operational headway adjustments according to congestion level of each car. It also aims to spread passengers out evenly and assess the degree of congestion on each car by measuring the weight of each car including passengers during peak and off-peak hours.

• 음성과학
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• 제5권1호
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• pp.89-103
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• 1999

It is relatively easy to develop a prototype of a Korean language processing system, but it is very difficult to make it an operational system. In this paper, we survey the current status and methodological issues of the Korean language processing systems such as morphological analyzer, parser and machine translator. In most cases, Korean language processing system easily comes to a dead-end state where its performance can not be improved any more. The reason is that it adopts a general algorithm covering similar problems as a whole because specific low-level problems are not clearly defined and their algorithms are unclear. So, when we add some restrictions to solve an individual linguistic problem, they are also applied to other linguistic phenomena as a side effect. It causes a critical problem that the improvement of the algorithm is very difficult. This paper proposes a 2-step paradigm, a divide-and-conquer method by the functional modularization, a simplification method, and an exception handling technique to develop an operational system that does not fall into a dead-end state.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 추계종합학술대회
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• pp.871-874
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• 2002

최근 정보통신 서비스가 대용량 고속화 및 멀티미디어화되고 일반 주거 지역으로의 유입 및 네트워크 설비 구축이 활성화되면서 기존의 전화망에 의한 단순 음성통신 또는 데이터 통신 환경과는 다른 시설 패러다임이 이루어지고 있다. 이에 본 논문에서는 댁내통신설비의 고도화를 위하여 운영환경요소를 분석하고 국내외 표준화 현황을 살펴보고 현재의 댁내통신설비의 운영환경에 대한 현장조사를 통한 문제점과 개선방안을 제시하였다.

• 한국군사과학기술학회지
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• 제15권5호
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• pp.660-666
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• 2012

The weapon system is getting more and more expensive, complex and smarter. Therefore, efficiently and effectively, it is important to operate the weapon system. OMS/MP is a document to quantify operational factors like as environment, mission, mode etc. It is important data to perform RAM analysis in early weapon development phase and operate better a weapon system. This paper present a process and framework of OMS/MP for a naval ship with a deep analysis of relevant domestic and abroad case studies. It propose OMS/MP analysis framework based on wartime scenario and mission area analysis. This result will contribute not only improvement for the availability of a naval ship but also enhancement of RAM analysis process.

• 대한조선학회지
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• 제25권1호
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• pp.47-55
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• 1988

One of tuna longliners which have excellent operational record at the tropical Pacifical Ocean was selected as a parent hull form for the development of a new ship which could be operate at the high latitude northern Pacific Ocean. The parent hull was modified to adapt operational and enviromental condition of such a weather and sea states. This modification was carried out based on design experiences and model test results in towing tank. In this report modification techniques applied to the hull form design of a tuna longliner are summarized. The powering performance of the developed hull form is evaluated to show 19%, decrease of resistance campared with the parent hull form.

• 한국국방경영분석학회지
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• 제27권2호
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• pp.110-123
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• 2001

This paper deals with the application of commercial mobile communication system for improvement of the military mobile wireless communication systems. Currently, commercial mobile communication systems are rapidly growing from first and second Generation system to third and forth Generation system, which can provide multimedia service of high speed and high capacity(e.g., IMT-2000). If we adapt these emerging commercial technology for the military communication, the military will have many benefits in terms of cost saving, early operational deployment and performance. And it is possible to support the communication necessary in the future warfield operational environment. Therefore, we analyzed differences between commercial systems and military systems, and adaptability in terms of security, survivability and performance. Finally, we proposed a stepwise utilization scheme to improve the military mobile wireless communication

• International Journal of Reliability and Applications
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• 제14권2호
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• pp.55-70
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• 2013

This paper deals with the Bayesian analysis of the failure data of a repairable mechanical system subject to minimal repairs and periodic overhauls. The effect of overhauls on the reliability of the system is modeled by a proportional age reduction model and the failure process between two successive overhauls is assumed to be 2-parameter Engelhardt-Bain process (2-EBP). Power Law Process (PLP) model has a disadvantage which 2-EBP can overcome. On the basis of the observed data and of a number of suitable prior densities, point and interval estimation of model parameters, as well as quantities of relevant interest are found. Also hypothesis tests on the effectiveness of performed overhauls have been developed using Bayes factor. Sensitivity analysis of improvement parameter is carried out. Finally, a numerical application is used to illustrate the proposed method.

• International Journal of Railway
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• 제3권1호
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• pp.34-37
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• 2010

In recent, the railway system consists of subsystems as rolling stock and infrastructures as signaling, telecommunication, power supply, overhead contact and platform screen door, etc. Furthermore, each subsystem has complicated interface so as not to understand these relationship. Consequently, to operate the railway system continuously with required safety and availability, the failure data should be corrected and analyzed systematically during operation. To achieve this object effectively, this paper presents the method which is evaluating the operational risk quantitatively using failure data, and selecting the critical equipment. Following this analysis, the improvement plan is established and applied to reduce the operational risk on system or equipment. From this study, the critical equipments of system could be determined and prioritized by risk analysis. Also, the effective maintenance to prevent critical failure could be implanted by this suggested methodology.

• 한국철도학회논문집
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• 제10권3호
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• pp.327-336
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• 2007

Operation a subway company requires high amount of early construction, operation and maintenance costs. Seoul Metro, one of the public subway companies in Seoul, Korea, has undergone operational deficit from its establishment, and the main reason is that the early construction and operation cost exceed the total revenue. Therefore, detailed researches on current operation system and possible alternatives are conducted to settle down finance trouble of the company. In particular, problems on operation and ticketing systems are analyzed, and based on that, necessity and detailed plan of railroad pass for one day are introduced and analyzed.