• Transportation Technology and Policy
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• v.9 no.2
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• pp.65-75
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• 2012

• Transportation Technology and Policy
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• v.9 no.3
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• pp.67-73
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• 2012

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.418-433
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• 1995

본 연구에서는 MPEG 트래픽과 같이 셀 흐름에 주기성을 갖는 비디오 트래픽 모형에 대한 쉐이핑 정책을 제시하고, 쉐이퍼에서의 셀손실율, 셀지연, 및 완만화 효과를 분석하였다. 분석 모형으로는 이산 상태 마코프 연쇄를 사용하였으며, 예제를 통해 시뮬레이션 결과와 비교하므로서 분석모형을 검증하였다. 분석 결과 셀지연 및 완만화 효과 사이에는 서비스율의 증가에 따라 trade off가 존재함이 나타났다. 본 연구는 ATM 트래픽관리에 있어서 다중화 장치에서의 성능분석과 병행하여 쉐이퍼의 설계에 있어서 정량화된 기초자료를 제공할 수 있을 것이라 여겨진다.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.6
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• pp.23-33
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• 1996

The exploitation of locality of reference in shared memory NUMA multiprocessors is one of the improtant problems in parallel processing today. In this paper, we propose a revised hardeare reference counter to help operating system to manage locality. In contrast to the previous one, the value of counter can abe adjusted dynamically and periodically to adapt the page replication policy to the various memory reference patterns of processors. We use execution-driven simulation of real applications to evaluate the effectiveness of our adjustable DELAY counter. Our main conclusijon is that by using the adjustable DELAY counter the t normalized average memory access costs and the variance of them become smaller for most applications than the previous one and more robust memory management policies can be provided for the operating systems.

• The Journal of the Korea Contents Association
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• v.3 no.3
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• pp.63-73
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• 2003

Today, in exponential growth of internet, the importance of file caching which could reduce the sun load, the volume of network traffic, and the latency of response has emerged. Actually, in one network, the traffic has reduced by using the cache and this means that file caching can improve the internet environment by cost a fraction of link upgrades. In this paper, we address a dynamic cache group configuration policy, to solve the scalable problem. The simulation result shows that the cache group using our proposal policy reduces the latency of response time and it means that out cache group configuration is more scalable than the static cache configuration.

• Journal of Digital Convergence
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• v.19 no.6
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• pp.373-385
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• 2021

In this study, the Korea Youth Policy Institute applied a self-registering model to verify the patterns of parental stress, multicultural youth psychological maladjustment, and interdependence between three factors by using five-point-time data tracked from middle school to high school. According to the analysis, First, Parent' stress at the time of the five surveys had a significant positive effect on the psychological maladjustment and the risk of academic interruption of multicultural adolescents at that point. Second, the psychological maladaptation of multicultural adolescents at the time of the previous five surveys had a significant positive effect on the risk of academic interruption at that point. Based on these analysis results, various support measures were proposed to cope with the stress of multicultural youth parents, and policy alternatives were proposed to prevent the risk of academic interruption by reducing the psychological maladjustment of multicultural youth.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.1
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• pp.20-33
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• 2002

Usage of ATM AAL2 packets becomes dominant to increase transmission efficiency of voice traffic in the backbone network. In case of voice service that uses AAL2 mechanism, if resources of network are enough, connection of new call is accepted. However, due to packets generated by the new call, transmission delay of packets from old calls can increase sharply. To control this behavior, in this paper we present an AAL2 buffer management scheme that allocates a virtual buffer to each call and after calculating its propagation delay variation(PDV), decides to drop packets coming from each call according to the PDV value. We show that this packet dropping algorithm can effectively prevent abrupt QoS degradation of old calls. To do this, we analyze AAL2 packet composition process to find a critical factor in the process that influences the end-to-end delay behavior and model the process by K-policy M/D/1 queueing system and MIN(K, Tc)-policy M/D/1 queueing system. From the mathematical model, we derive the probability generating function of AAL2 packets in the buffer and mean waiting time of packets in the AAL2 buffer. Analytical results show that the AAL2 packet dropping algorithm can provide stable AAL2 packetization delay and ATM cell generation time even if the number of voice sources increases dramatically. Finally we compare the analytical result to simulation data obtained by using the COMNET Ⅲ package.

• Journal of the Korea Society of Computer and Information
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• v.13 no.4
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• pp.31-37
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• 2008

In this paper, we propose a dynamic job relocation strategy that considering application's characteristics in multiple grid sites. This scheme classifies application to execute in multiple grid sites by their characteristics : computing intensive application, network intensive application. Also, it eliminates the communication between sites by allocating the network intensive application in single site, thus reducing the total job execution time. But if a number of free nodes to execute the network intensive application aren't found in single site, the proposed scheme the first allocates the network intensive application in multiple sites to minimize network latency. Then if the network intensive application being executed in multiple sites suitable free nodes are found in single site. the proposed scheme relocates the application being executed in multiple sites to another single site. This results in reducing the total job execution time. Through simulation, we show that the proposed dynamic job reallocation strategy improves the performance of Data Grid environment compared with previous strategies.

• The Transactions of the Korea Information Processing Society
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• v.5 no.11
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• pp.2997-3009
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• 1998

독자-필자 문제(readers-writers problem)를 위한 기존의 스케쥴링 정책들은 대부분 독자나 필자 중 어느 한 쪽에 편향된 처리 성향을 가지고 있기 때문에 응답 시간이나 처리량, 둘 중 하나의 성능이 상당히 좋지 않은 특성이 있다. 본 논문에서는 이러한 문제를 개선하고자 새로룬 동적 스케쥴링 정책인 CAP(Counter-based Adaptive Priority)을 제안한다. CAP은 동시에 수행될 수 없는 필자에게 가중치를 주는 기법과 소수의 독자를 무작정 지연시키는 것을 막기 위한 에이징(aging) 기법을 동적으로 결합하여 사용하고 있다. CAP은 기는(starvation) 문제를 가지고 있지 않으며 주어진 상황에 동적으로 대응하는 능력을 가지고 있기 때문에 처리량과 응답 시간 모두 FCFS에 비하여 더 우수하다. 제안된 정책에 대한 효과성을 입증하기 위하여 세마포어 기반의 해법을 제시하고 사건-기반 시뮬레이션을 사용하여 기존의 정책들과 성능을 비교하였다.

• Journal of the KSME
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• v.20 no.1
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• pp.8-13
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• 1980

Enegy 위기의 근본이유는 현재 이용되고 있는 Energy의 근원이 재생 불가능한 연료이기 때문 이다. 그래서 Energy 자원이 고갈됨에 따라 생산가는 점점 높아지고 이러한 자원에 계속 의존 하게 되면 가격은 끝없이 상승되게 된다. 이러한 과정은 강력한 Inflation 을 유발시키고 생활비의 부담을 낳게되며(특히 하류층에) 자본의 유용성을 감소시키게 된다. 이러한 압력하에서는 어떠한 경제구조도 견디어 낼 수 없음이 분명 하므로 이 Energy 위기는 가까운 시일안에 해결되어야 한다. 이 해결책은 단지 Oil, 천연Gas, 석탄, Uranium등의 재생불가능 연료를 가격적으로 안정 될 수 있는 재생가능성의 연료로 대체하는 것 뿐이다. 이 방법의 사용이 지연되어 상황이 나빠지지 않도록 하는 정책이 필요하며 이 정책의 실재적으로 중요한 문제점은 어떠한 정책과도 마찬가 지로 그 정책이 불능한가와 가능하다면 어떻게 해야 하는가 즉 방법이란 것으로 귀결된다.