• 디지털융복합연구
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• 제4권1호
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• pp.17-30
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• 2006

Recently, Modeling and Simulation, which have been received attention in various in dustries such as national defence, eduction and entertainment, have been researched, and related applications have been developed actively. Especially, it is focused on the to chnology of a virtual reality and a virtual simulation which represents the implementation technology for the simulation education related to the e-Learning industry. However, a solution is needed to fulfill the lack of technology and research about standardize d data elements which could be applied to virtual simulation technologies in common. Therefore, this article suggests the virtual simulation data elements to increase the educational effect of a virtual simulation and interoperability of data among LMS through reference to korean and international standards and the result of related area analysis. In other words, this article aims to define the expression of data element and to propose the guideline elements in the virtual simulation scope.

• 디지털융복합연구
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• 제11권2호
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• pp.175-182
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• 2013

본 연구에서는 주택 수요와 공급의 상호영향관계 메커니즘을 이용하여 가격 시뮬레이션 모형을 개발하였다. 가격 시뮬레이션 모형의 핵심 알고리즘은 피드백 제어 이론을 이용한 시스템 다이나믹스 기반의 스톡 플로우 변수이며, 이러한 원리를 이용하여 서울지역 아파트 가격변화 행태를 모델링하였다. 가격 행태를 결정하는 피드백 메커니즘은 중장기 경기변동 시나리오 하에 대출 이자율을 정책변수로 아파트 매매 수요자와 공급자 규모를 스톡 변수로 설정하고, 이들 간의 상호 영향관계를 검증하였다. 본 논문을 통하여 향후 아파트 가격 추이는 아파트 매매 수요자와 공급자 규모의 행태 변화와 수요자와 공급자가 갖는 가격에 대한 반응 매개변수간의 영향관계로 구성된다. 또한 향후 경기 전망 및 대출이자율 등 거시경제의 상황에 따라 아파트 매매가격은 변화함을 알 수 있었다. 제시된 아파트 매매 가격 시뮬레이션 계량모델은 양도세 및 취득세 감면 등 비 금융 관련 부동산정책변수와 대출이자 조정 등 금융 관련 정책변수의 보다 정확하고 충분한 데이터를 적용하면 실무 적용과 정부 주택정책입안에 활용 할 수 있을 것으로 판단된다.

• Journal of applied mathematics & informatics
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• 제32권1_2호
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• pp.129-136
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• 2014

One of the fundamental issues in the design of dynamic spectrum access policy is the modeling of the dynamic behavior of channel occupancy by primary users. Under a Markovian modeling of channel occupancy, a periodic sensing and greedy access policy is known as one of the simple and practical dynamic spectrum access policies in cognitive radio networks. In this paper, the primary occupancy of each channel is modeled as a discrete-time alternating renewal process with generally distributed on- and off-periods. A periodic sensing and greedy access policy is constructed based on the general channel occupancy model. Simulation results show that the proposed policy has better throughput than the policies using channel models with exponentially distributed on- or off-periods.

• 한국시스템다이내믹스연구
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• 제14권1호
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• pp.55-68
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• 2013

It is necessary to evaluate the greenhouse gases (GHGs) reduction policy by central and regional governments to set up the suitable GHG emissions measures. Quantitative, qualitative and synthetic methods have been adopted by previous researches to estimate GHG reduction policy. However, these methods mostly focused on the results of the reduction policy, rather than understanding and fixing the integrated structures of GHG emissions. In this research, System Dynamics(SD) was applied to 1 million green homes program, self-carfree-day system and carbon point program. The results showed that SD analyses could be appliable for the estimation of GHG reduction policy by developing the feedback loops and dynamic simulation model. SD can be consider as a supplementary tool to estimate the GHG reduction policies through the recognition of the structure in complex real system.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2004년도 춘계공동학술대회 논문집
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• pp.31-34
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• 2004

This research proposes the lateral transshipment policy that can deal efficiently with stockout in the two-echelon distribution network in supply chain. The lateral transshipment policy can be expected for retailers to response the change of customers' demands efficiently. Because of various factors, such as demand fluctuation, replenishment quantity, lead time, and so on, it is very difficult to decide optimal lateral transshipment time and quantity. We suggest the new lateral transshipment policy based on the service level in this research. The efficiency of this policy is proved by simulation experiments.

• 산업공학
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• 제13권3호
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• pp.438-443
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• 2000

In this paper, we suggest a new backorder policy for stockout which is occurred in each regional distribution centers of distribution chain for capital-goods product. In backorder process of backorder policy, minimize expected stockout through the balancing-division module, and has occured stockout is backordering through the emergency supply from central distribution center and regional distribution center. Simulation tests show that our backorder policy is on the decrease of backorder cost and improvement of customer service. Our backorder policy has two important benefit. First, customer service level is improved by realization of minimum stockout. Second, the backorder process by allowance of the same level supply is to decrease system operating cost.

• 한국경영과학회지
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• 제24권3호
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• pp.39-47
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• 1999

It has been concluded that the performance of class-based storage policy is better than the performance of random storage policy in the literature. However, the rack shortage problem assigned to the 1st class items makes the decision hard to apply the class-based storage policy in practice. In this paper, a new common zone concept is introduced between two classes to resolve the problem with class-based storage policy. The common zone is the area to accept items from both classes. An AS/RS model is developed for computer simulation study and the effect of common area sizes with various AS/RS operation conditions is analyzed.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권1호
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• pp.7-14
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• 2017

Due to the recent advances in Phage-Change Memory (PCM) technologies, a new memory hierarchy of computer systems with PCM is expected to appear. In this paper, we present a new page replacement policy that adopts PCM as a high speed swap device. As PCM has limited write endurance, our goal is to minimize the amount of data written to PCM. To do so, we defer the eviction of dirty pages in proportion to their dirtiness. However, excessive preservation of dirty pages in memory may deteriorate the page fault rate, especially when the memory capacity is not enough to accommodate full working-set pages. Thus, our policy monitors the current working-set size of the system, and controls the deferring level of dirty pages not to degrade the system performances. Simulation experiments show that the proposed policy reduces the write traffic to PCM by 160% without performance degradations.

• 한국경영과학회지
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• 제30권1호
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• pp.17-26
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• 2005

There is the uncertainty of demands at each retailer in the supply chain. To satisfy customers' demand, retailer must have enough inventory. Nevertheless, stockout is occurred for some retailers. A lateral transshipment policy can be effectively used to deal with stockout. The new lateral transshipment policy, referred to service level adjustment (SLA), is suggested. The difference between SLA and previous policies is the integration of an emergency lateral 'transshipment with a preventive lateral transshipment to efficiently respond customers' demand in the proposed policy. Additionally, the service level to decide the quantity of products is considered. Simulation experiment is executed to treat stochastic factors in the two-echelon supply chain. The proposed policy can reduce total cost and is more effective to the change of demand, penalty cost, and ordering cost than the currently used policies.

• 대한산업공학회지
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• 제22권3호
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• pp.313-324
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• 1996

A new policy to determine the waiting position of an idle Automated Guided Vehicle(AGV) is proposed and its performance is compared with the existing waiting position policies. Unlike the existing policies, the queue length in the input buffer is considered in the new policy. As a result, the waiting position based on the new policy depends on the status of the system. The simulation result indicates that the proposed policy reduces the waiting time in both the input and the output buffers significantly, regardless of the number of AGVs in the system. Therefore, the manufacturing lead time can be minimized.