• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 2006년도 춘계학술대회
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• pp.463-468
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• 2006

구매자와 공급자의 관계는 대부분 구매자의 교섭력이 우위에 있는 경우가 대부분이지만, 병목품목의 경우는 반대로 공급자의 교섭력이 우위에 있는 상대적으로 드문 경우에 해당된다. 병목품목에 대해 힘의 열위에 있는 구매자가 주도할 수 있는 구매 및 공급관리 전략을 도출하고 실행하기는 다른 품목들에 비해 매우 어렵다. 그러나 교섭력의 부족으로 인하여 공급이 부족하게 되면 생산에 막대한 차질을 가져오고, 공급량은 부족하지 않더라도 공급가격이 인상되면 구매비용이 증가하게 되어 최종제품의 가격과 수익에 큰 영향을 미치게 된다. 본 연구에서는 그동안 상대적으로 연구가 부족하였지만 제품생산과 수익에 중요한 영향을 미치는 병목품목에 대해 구매 포트폴리오를 기반으로 하여 구매 및 공급관리 전략의 목표를 정의하고, 목표를 이루기 위한 프레임웍과 전략들을 도출하였다.

• 한국콘텐츠학회논문지
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• 제7권8호
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• pp.66-75
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• 2007

전통적인 SNMP를 이용한 중앙집중형 네트워크 관리 방식은 빈번한 폴링에 의한 통신량의 증가와 특정관리 노드에 병목 현상이 생기는 문제점을 안고 있다. 이러한 문제를 해결하고 극복하기 위한 이동 에이전트에 의한 네트워크 관리방식들이 연구되어 오고 있다. 그러나 이동 에이전트에 의한 네트워크 관리 방식은 관리해야 될 노드가 증가함에 따라 이동되는 데이터량이 누적 증가되어 효율성이 떨어진다. 이러한 문제점을 해결하기 위하여 본 논문에서는 이동에이전트를 이용한 분할관리 방식을 제안한다. 제안된 방법에서는 노드들은 그룹들로 나누어지고 별도의 이동에이전트들에 의하여 관리된다. 각각의 이동에이전트들은 자신의 노드들을 방문하고 정보를 수집한다. 제안된 방법이 효율적임을 실험을 통하여 보였다.

• 환경정책연구
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• 제2권1호
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• pp.51-75
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• 2003

The objective of this study is to analyze the problems of disposal and collection, including administrative management of agricultural PE waste and suggest effective management measurements. Information regarding problems of agricultural PE waste management were collected from field survey of farmers, regional governments and officials. On the national level, the low ratio of collection for optimal treatment of agricultural PE waste is a critical problem. , the negative discharging behavior of farmers, an illegal incineration and landfill of farmers and a lack of education and extension etc. An ambiguity of the management principle to agricultural PE waste, the differences in management among the regional governments, a lack of will of the regional governments and officials to realize SARD and lack of education and extension etc. are some of the problems in administrative management of agricultural PE waste collection. The major suggestions of this study are as follows : (1) to strengthen education and extension, (2) to adopt an improved economic incentive system and strong, lawful regulation simultaneously, (3) to use temporang collection and permanent collection site, and (4) to organize "OTC(Optimal Treatment Conference)" composed of farmers, regional cooperative, PE producers etc. for operating an effective management system.

• 반도체디스플레이기술학회지
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• 제9권2호
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• pp.67-72
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• 2010

Recently increasing application of flash memory in mobile and ubiquitous related devices is due to its non-volatility, fast response time, shock resistance and low power consumption. Following this trend, SSD(Solid State Disk) using multiple flash chips, instead of hard-drive based storage system, started to widely used for its advantageous features. However, flash memory based storage subsystem should resolve the performance bottleneck for writing in perspective of speed and lifetime according to its disadvantageous physical property. In order to provide tangible performance, solutions are studied in aspect of reclaiming of invalid regions by decreasing the number of erasures and distributing the erasures uniformly over the whole memory space as much as possible. In this paper, we study flash memory recycling algorithms with multiple management units and demonstrate that the proposed algorithm provides feasible performance. The proposed method utilizes the partitions of the memory space by utilizing threshold values and reconfigures the management units if necessary. The performance of the proposed policies is evaluated through a number of simulation based experiments.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2001년도 추계학술대회 논문집
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• pp.21-24
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• 2001

This study is concerned with the development of efficient p-median approach to nondegenerate cell formation(CF) in group technology(GT) manufacturing. Unlike most of existing CF methodologies allowing degenerate cells or families that contains no parts or machines, this study attempts to find cell configuration where each machine cell contains at least two or more machines processing at least two or more parts so as to fully utilize the similarity in designing and processing parts. Nondegenerate CF seeks to minimize both the exceptional elements outside the diagonal block and the voids within the diagonal block. To find nondegenerate cells, a two-phase p-median methodology is proposed. In phase 1, the classical p-median model is implemented to find initial cells. In phase 2, bottleneck machines and parts are reassigned until no further degenerate cells and families are found. Test results on moderately medium-sized CF problems show the substantial efficiency of the proposed approach.

• 한국경영과학회지
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• 제29권4호
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• pp.175-187
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• 2004

We consider the simultaneous selection of part routes for multiple part types in Flexible Manufacturing Systems (FMSs). Using an optimization framework we investigate two alternative route assignment policies. The one, called routing mix policy in the literature, specifies the optimal proportion of each part type to be produced along its alternative routes, assuming that the proportions can be kept during execution. The other one, which we propose and call pallet allocation policy, partitions the pallets assigned to each part type among the routes. The optimization framework used is a nonlinear programming superimposed on a closed queueing network model of an FMS which produces multiple part types with distinct repeated visits to certain workstations. The objective is to maximize the weighted throughput. Our study shows that the simultaneous use of multiple routes leads to reduced bottleneck utilization, improved workload balance, and a significant increase in the FMS's weighted throughput, without any additional capital investments. Based on numerical work, we also conjecture that pallet allocation policy is more robust than routing mix policy, operationally easier to implement, and may yield higher revenues.

• 한국CDE학회논문집
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• 제11권1호
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• pp.11-19
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• 2006

For several years, a research about the simulation for shipyard and shipbuilding has been performed. This research is based on the concept of PLM (Product Lifecycle Management) and DM (Digital Manufacturing). Global leading companies and research center are trying to get a good position of PLM, especially M&S field. Digital shipbuilding is to computerize shipyard facilities and shipbuilding processes, and to simulate expected scenarios of shipbuilding processes using a computer model in order to resolve a potential problem such as a bottleneck processes, and over loaded resources. In this paper, simulation methodology for shipbuilding is described. In addition, a local and global strategy for the use of simulation methodology is suggested. Finally, case studies about an indoor shop and an outdoor shop are described.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1990년도 춘계공동학술대회논문집; 한국과학기술원; 28 Apr. 1990
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• pp.299-311
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• 1990

A computer simulation model is proposed for selecting effective agrees paths and estimating the evacuation time in case of evacuating all the residents of a building to the safe area. The physical structure of a building is formulated into a network. The followings are considered in the model : the congestion effect to the velocity, the behavioral pattern of the evacuees, and the probabilistic nature of the evacuation process. Coded in SLAM II/PC, the simulation model can generate the output such as evacuation time(max, average), utilization of exits, utilization of passages, floor clearance times, and bottleneck information. The "rigorous" validation of the proposed model is not completed yet but remains to be a future research topic.rch topic.

• 정보처리학회논문지C
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• 제11C권1호
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• pp.89-98
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• 2004

인터넷의 혼잡상황을 해결하기 위하여 제안된 RED(Random Early Detection)와 같은 능동적 큐 관리(Active Queue Management) 알고리즘들은 TCP 데이터에 대하여 우수한 혼잡제어 효과를 나타낸다. 그러나 TCP와 UDP가 병목 링크를 공유하는 경우 불공정성 문제와 큐에서의 지연시간이 길어지는 문제점을 가지고 있다. 본 논문에서는 공정성을 개선함과 동시에 큐 지연시간을 감소할 수 있는 새로운 큐 관리 알고리즘인 PSRED(Protocol Sensitive RED) 알고리즘을 제안하였다. PSRED 알고리즘은 트래픽의 프로토콜 필드를 이용하여 플로우의 종류를 구분하고 각기 다른 패킷폐기함수를 적용함으로써 공정성을 개선하고 평균 큐 길이를 줄일 수 있다.

• 디지털산업정보학회논문지
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• 제5권3호
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• pp.19-28
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• 2009

Computer system performance has always had the possibility of affecting business profitability, but with the advent of the World Wide Web where customers interact directly with Web servers, response time can have a direct and dramatic impact on business revenue. This paper is written in the operation environment and system analysis of HTS(Home Trading System) running K Securities. This paper also shows the method for performance improvement through investigation and analysis for the overall systems resources whether HTS has an appropriate performance or not. Performance analysis includes specially CPU analysis, Memory analysis, Disk Input/Output analysis and application analysis. Besides providing more detailed server specification for expansion from now on, system performance can be maintained with effect in the future. Through this study it is possible to manage the performance of HTS more easily and to solve problems such as a bottleneck more quickly.