• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2003년도 추계학술대회 및 정기총회
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• pp.27-34
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• 2003

A distributed server cluster system is a cost-effective system to provide a service application for clients with reliable, scalable, available, and fault-tolerant features. In order to provide high quality services, it is necessary to evaluate service performances, tune the server system, and analyze performances. In this paper, we propose a simulator to generate workloads based on statistic configuration according to estimated application traffics, apply workload scheduling algorithms, and evaluate the simulation results. We introduce the simulator design modelling and architecture. By using flexible parameters, the simulator is able to generate various patterns of workloads with different statistics, and configure system environments such as the number of server nodes, system resources considered, and their capacities. With this simulator, we introduce two scenarios: one is to find appropriate thresholds for the best performance of cluster system, and the other is to find the suitable scheduling algorithm for workload characteristics of service applications.

• 산업공학
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• 제17권3호
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• pp.294-304
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• 2004

In the IS-95 packet service system, the radio channels are generally classified into the dedicated and common traffic channels. In this paper, the performance of the common traffic channel access method is evaluated using simulation. The simulation results are compared with those of random access method. Simulation results show that the capacity can be increased up to 25% by applying the proposed common channel access method. The delay problem and variance of BER are also discussed.

• 한국시뮬레이션학회논문지
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• 제14권1호
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• pp.33-42
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• 2005

Service Level Agreement (SLA) is a service providing scheme by a service class agreement between a user and a service provider SLA allows that a user can select an expected service class in various service classes provided from a service provider. Recently, SLA management is adapted to support the end-to-end Qos for service users in Beyond 3 Generation (B3G) networks. In B3G networks, SLA provides multiple service classes on access networks so that service classes should be managed to assure the service satisfaction for users. In this paper, we propose a dynamic Qos management scheme by IP traffic class controlling based on SLA in B3G networks. Also, to manage dynamic traffic service, we consider Differentiated services (Diffserv) mechanism for the resource management by SLA. An If service traffic class on SLA can be dynamically changed by Diffserv traffic management to support dynamic end-to-end Qos. Hence, in this paper, we consider the buffer threshold scheme for controlling traffic loads and the traffic level control scheme for implementing the dynamic traffic management by the SLA.

• 한국간담췌외과학회지
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• 제27권4호
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• pp.428-432
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• 2023

Minimally invasive pancreatoduodenectomy (MIS PD) is a well reported technique with several advantages over conventional open pancreatoduodenectomy. In comparison to distal pancreatectomy, the adoption of MIS PD has been slow due to the technical challenges involved, particularly in the reconstruction phase of the pancreatojejunostomy (PJ) anastomosis. Hence, we introduce a lowcost model for PJ anastomosis simulation in MIS PD. We fashioned a model of a cut pancreas and limb of jejunum using economical and easily accessible materials comprising felt fabric and the modelling compound, Play-Doh. Surgeons can practice MIS PJ suturing using this model to help mount their individual learning curve for PJ creation. Our video demonstrates that this model can be utilized in simulation practice mimicking steps during live surgery. Our model is a cost-effective and easily replicable tool for surgeons looking to simulate MIS PJ creation in preparation for MIS PD.

• 한국통신학회논문지
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• 제27권4C호
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• pp.316-325
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• 2002

This paper investigates the restoration schemes which are applied to the MPLS domain upon a network failure. We define the following three restoration service models by combining the various restoration schemes: "FIS-based protection service" (FIS: failure indication signal), "inversion traffic protection service" and "1+1 protection service". After a qualitative analysis of the performance in them, we have analyzed it on quantitative basis by the simulation. According to the simulation results, "1+1 protection service" guarantees the fastest and most lossless restoration service among them; however, it results in consuming considerable bandwidth and producing an amount of control traffic, which means poor network utilization. On the other hand, "FIS-based protection service" spends less bandwidth and generates less control traffic, which means better network utilization, but produces poor restoration service. "Inversion traffic protection service" provides the medium restoration service and utilization between "1+1 protection service" and "FIS-based protection service."

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2003년도 추계학술대회 및 정기총회
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• pp.95-103
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• 2003

Event notification service is a event-based messaging middle ware service needed for various vertical domains, such as, business applications, distributed system management, and web service integration. In this paper, we investigate the architecture of an event notification service that includes a subject-based event dissemination service and a flexible message communication service. The event dissemination service is in charge of transferring events asynchronously but speedy according to the subjects of events and their environmental knowledge. It also includes content-based message filtering. The message communication service provides a common communication infrastructure supporting variety types of messages and variety of protocols. Depending on application domains and situation, we can re-configurate the communication infrastructure in order to optimize the efficiency and usability. This paper shows the performance analysis of our event notification service with various types of message formats and protocols.

• 한국시뮬레이션학회논문지
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• 제22권3호
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• pp.43-53
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• 2013

본 연구는 소상공 서비스 회사의 이익을 극대화하고, 배달음식을 고려함에 있어서 소비자의 편의성을 증대시키며, 노인의 사회참여를 활성화시키기 위한 방안으로 배달을 외주화하는 방안을 수립하기 위한 연구이다. 이를 위해 일반적으로 집에서 자주 주문하는 음식인 중국음식점을 대상으로 물류 시스템을 개선하여 업체와 소비자, 외주 배달 업체 모두 Win-Win-Win 할 수 있는 전략을 수립하고자 시뮬레이션 분석을 수행하였다. 시뮬레이션에 사용된 입력데이터는 실제 중국음식점에서 발생하는 데이터와 인터뷰 결과를 통하여 얻은 데이터를 정리하여 사용하였다. 외주 배달 업체의 배달인원과 이용요금에 따라 총 6가지의 시나리오를 설정하였으며, 각 시나리오별로 3개 음식점의 상황을 달리하여 시뮬레이션 실험을 실행하여 결과를 분석하였다. 분석결과 외주 배달을 이용할 경우 소상공 서비스 회사는 매출과 이익의 증대를 이룩할 수 있으며, 소비자는 자신이 원하는 음식을 보다 빨리 배달받을 수 있게 된다. 또한 외주 배달 운영 업체는 노인을 고용하여 수익을 낼 수 있으며, 이를 통해 노인문제를 해결하기 위한 하나의 방안으로 활용될 수 있을 것으로 판단된다.

• 디지털산업정보학회논문지
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• 제5권3호
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• pp.107-115
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• 2009

Traditionally, simulation method is used to test and evaluate the performance of communication protocol or functional elements for mobile communication service. In this paper, wireless network simulator is implemented using the C++ object-oriented programming language. This simulator can simulate wireless data services, like as ad-hoc networks, by considering the user's mobility. In this paper, the simulator includes network traffic model to reflect wireless data service and traffic source model to represent a user's mobility similar to real service environment and traffic characteristics can be reflected on the simulation, and also more accurate simulation results can be got through that. In addition, by using object-oriented techniques, new service feature or environment can be easily added or changed so that the developed mobile communication simulator can reflect the real service environment all the time. This simulator can be used in adjusting the characteristics of wireless data hosts following the mobility of the user, and also can be used in building new wireless ad-hoc network routing protocols.

• 한국시뮬레이션학회논문지
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• 제13권2호
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• pp.65-73
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• 2004

The capability to provide the network service must survive even if a significant network system element is disrupted. To sustain the network service under the system failure, network survivability mechanisms minimizing the impact of failures are needed. Also, since the mobile network has its unique characteristic, the survivability scheme for the vulnerability of the mobile network is required. This paper proposes a survivability scheme to support the reliable service of the wireless access point level (BS-base station system). By the survivability scheme, the mobile network can use an overlap BS of the cellular network architecture after a BS system failure. We analyze the performance of the proposed scheme using Markov model. Also, a computer simulation is used for the scheme analysis. The proposed scheme shows that the service of the mobile network can be provided under the BS system failure.

• 정보과학회지
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• 제5권2호
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• pp.49-60
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• 1987

待期 理論(Queuing, waiting-Line Theory)은 例을 지어 待期하고 있는 現 象, 즉 各種 窓口에서 特定의 서어비스를 提供받기 위하여 個體가 기다리는 現象 에 관한 理論이며, 이와같은 理論的인 現象을 待期行列現象(Queuing phenomena, Waiting-Line phenomena)이라고 한다.