• ETRI Journal
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• 제37권5호
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• pp.856-866
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• 2015

A heterogeneous network (HetNet) is a network topology composed by deploying multiple HetNets under the coverage of macro cells (MCs). It can improve network throughput, extend cell coverage, and offload network traffic; for example, the network traffic of a 5G mobile communications network. A HetNet involves a mix of radio technologies and various cell types working together seamlessly. In a HetNet, coordination between MCs and small cells (SCs) has a positive impact on the performance of the networks contained within, and consequently on the overall user experience. Therefore, to improve user-perceived service quality, HetNets require high-efficiency network protocols and enhanced radio technologies. In this paper, we introduce a 5G HetNet comprised of MCs and both fixed and mobile SCs (mSCs). The featured mSCs can be mounted on a car, bus, or train and have different characteristics to fixed SCs (fSCs). In this paper, we address the technical challenges related to mSCs. In addition, we analyze the network performance under two HetNet scenarios-MCs and fSCs, and MCs and mSCs.

• 산업경영시스템학회지
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• 제32권4호
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• pp.17-24
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• 2009

The purpose of this research is to find the reasons of overcrowding in the emergency department of an hospital, then to shorten the total stay time of patients. The fact that main causes of the overcrowding exist in the process of the emergency department was discovered by analysis of the data. In order to improve these process, simulation model was developed by ARENA 7.0. Staff's service time, staff's organization, process ratio, and patient's waiting time were estimated in the simulation model in consideration of the decision of the patient's course of action. Several scenarios such as the simplification of the process, the setup of dedicated pathology lab, and mixed method were suggested and evaluated. Total stay time of the patients would be reduced up to 28.45%.

• Journal of Construction Engineering and Project Management
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• 제1권3호
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• pp.45-51
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• 2011

During disaster response, prioritization of limited resources is one of the most important but challenging tasks. At the same time, it is imperative to timely provide to the rescuers with the adequate heavy equipment to facilitate lifesaving operations. However, supply of high demand equipment is usually insufficient during the initial phase of disaster response, challenging lifesaving operations. At the same time, resources outside of the disaster affected zone converge into the area to assist the response efforts, which is the effect of convergence that often made resource coordination challenging in large scale disasters. Meanwhile, the initial condition of the disaster is usually best known by civilians already at the area before and during impact of the disaster. The knowledge of the civilians is not always received and considered by the responding organizations. With the help of these civilians, critical information such as victim location, infrastructure damage, and risk condition could be better know before any response actions are taken. To efficiently collect information and utilize the converging resources, this paper proposes a geospatial information repository for initial condition reporting and update to guide search and rescue operations and deployment of equipment with safety considerations for the rescuers in large scale disaster response scenarios.

• 한국통신학회논문지
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• 제36권8B호
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• pp.897-903
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• 2011

본 논문에서는 현재 육군에서 진행하고 있는 VoIPv6 네트워크 구축 사업에 적용될 예정인 네트워크를 시뮬레이션을 통해 성능을 예측하고 그 결과를 도출하였다. 본 논문의 시뮬레이션에 앞서 선행하였던 첫 번째 u-Army 시뮬레이션의 경우 실험 부대 내로 범위를 한정하여 VoIPv6 네트워크의 성능을 측정하였다면 이번 시뮬레이션에서는 범위를 확장하여 사단 전체에 적용하였을 경우 설계한 VoIPv6 네트워크가 어느 정도의 성능이 나오고 실제 육군의 요구사항에 부합하는지를 예측하는 시뮬레이션이다. 시뮬레이션은 사단에 실제 적용할 네트워크를 모델링하여 사용하였고, 서비스를 사용하는 다양한 상황을 가정하고 시뮬레이션 조건으로 적용하여 네트워크에서 어느 정도까지 서비스를 제공할 수 있는 지를 시뮬레이션 하였다. 도출된 결과는 네트워크의 성능을 예측하여 향후 전군으로 적용될 경우 군 상황과 규모에 적합한 네트워크 구축에 도움을 줄 것이다

• 한국게임학회 논문지
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• 제3권2호
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• pp.12-18
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• 2003

좋은 게임은 독특하고 개성이 뚜렷한 콘텐츠에서 얻어진다. 게임의 콘텐츠는 게임시나리오로 표현되는 만큼, 게임개발은 시나리오창작 작업이 선행되어야 한다. 게임시나리오의 창작은 시나리오기획서로 결과가 나와야 한다. 기획서는 게임개발을 위한 설계도이기 때문이다. 그러나 게임을 제작하는 회사에서나 게임을 교육하고 있는 학계에서는 제대로 된 게임시나리오의 기획서를 쓰지 않고 있는 형편이다. 물론 게임기획서에 시나리오를 대충 삽입시켜버 리는 우리의 게임제작 습성도 한 몫을 하고 있지만, 가장 큰 문제점은 제대로 된 게임시나리오기획서의 서식이 없기 때문이기도 하다. 본고에서는 기획서의 서식에 들어갈 내용들을 간단하게나마 연구하여, 게임 기획서의 기본 서식의 틀을 제안해 보는 것이 목적이다.

• 대한예방한의학회지
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• 제14권1호
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• pp.77-96
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• 2010

Objectives : This paper recommends a global budget based payment system for reimbursing oriental medical services in the national health insurance. Methods : We analyzed previous research outcomes related to oriental medical services and payment system We reviewed the experiences of other countries' global budget system in terms of their strength and weakness. In addition, we developed a reimbursement method for oriental medical services based on global budget. Results : Our reviews focused on global budget system of Germany, the Netherlands, the United Kingdom, Canada, France, and Taiwan. The estimation of global budget in the national health insurance was described in two scenarios. First scenario was to allocate oriental medical services in scale after signing a contract for global budget. In this case, 4.16% of the national health insurance expenditure was allocated for the oriental medical services. Second scenario was to estimate the global budget in a historical context. As a result, the first scenario in total budget was higher than the second, and we proposed a retrospective adjustment method for the gap between the budget and the actual expenditure Conclusions : The payment system for oriental medical services is recommended to shift from fee-for-service to global budget.

• 정보처리학회논문지C
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• 제12C권2호
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• pp.217-222
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• 2005

IEEE 802.11기반 무선 랜은 가정과 사무실 환경에서 무선 연결 서비스를 제공하는 대표적인 기술이다. 최근 들어 HDTV나 화상회의 또는 VoIP와 같은 실시간 멀티미디어 서비스들에 대한 요구가 증가함에 따라 이를 뒷받침하기 위한 QoS (Quality of Service) 지원 메커니즘인 IEEE 802.11e가 제안되었다. 본 논문에서는 IEEE 802.11e 기술이 확산되면서 발생할 수 있는 IEEE 802.11e와 IEEE 802.11b 기술의 혼재 상황에서의 불공평 문제에 대하여 다룬다.

• Journal of Information Processing Systems
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• 제13권1호
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• pp.184-195
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• 2017

In recent decades, the ad hoc network for vehicles has been a core network technology to provide comfort and security to drivers in vehicle environments. However, emerging applications and services require major changes in underlying network models and computing that require new road network planning. Meanwhile, blockchain widely known as one of the disruptive technologies has emerged in recent years, is experiencing rapid development and has the potential to revolutionize intelligent transport systems. Blockchain can be used to build an intelligent, secure, distributed and autonomous transport system. It allows better utilization of the infrastructure and resources of intelligent transport systems, particularly effective for crowdsourcing technology. In this paper, we proposes a vehicle network architecture based on blockchain in the smart city (Block-VN). Block-VN is a reliable and secure architecture that operates in a distributed way to build the new distributed transport management system. We are considering a new network system of vehicles, Block-VN, above them. In addition, we examine how the network of vehicles evolves with paradigms focused on networking and vehicular information. Finally, we discuss service scenarios and design principles for Block-VN.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권1호
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• pp.35-57
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• 2014

Multi-criteria decision making (MCDM) algorithms play an important role in ensuring quality of service in an integrated HetNets (Heterogeneous Networks). The primary objective of this paper is to develop a multi-criteria vertical handoff decision algorithm (VHDA) for best access network selection in an integrated Wireless Local Area Network (WLAN)/Universal Mobile Telecommunications System (UMTS)/Worldwide Interoperability for Microwave Access (WiMAX) system. The proposed design consists of two parts, the first part is the evaluation of an Analytic Hierarchy Process (AHP) to decide the relative weights of handoff decision criteria and the second part computes the final score of the weights to rank network alternatives using Simple Additive Weighting (SAW). SAW ranks the network alternatives in a faster and simpler manner than AHP. The AHP-SAW mathematical model has been designed, evaluated and simulated for streaming video type of traffic. For other traffic type, such as conversational, background and interactive, only simulation results have been discussed and presented in brief. Simulation results reveal that the hierarchical modelling and computing provides optimum solution for access network selection in an integrated environment as obtained results prove to be an acceptable solution to what could be expected in real life scenarios.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권10호
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• pp.4015-4033
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• 2015

The future mobile networks consist of hyper-dense heterogeneous and small cell networks of same or different radio access technologies (RAT). Integrating mobile networks of different RATs to provide seamless and smooth mobility service will be the target of future mobile converged network. Generally, handover from high-speed networks to low-speed networks faces many challenges from application perspective, such as abrupt bandwidth variation, packet loss, round trip time variation, connection disruption, and transmission blackout. Existing inter-RAT handover solutions cannot solve all the problems at the same time. Based on the high-layer convergence sublayer design, a new receiver-aided soft inter-RAT handover is proposed. This soft handover scheme takes advantage of multihoming ability of multi-mode mobile station (MS) to smooth handover procedure. In addition, handover procedure is seamless and applicable to frequent handover scenarios. The simulation results conducted in UMTS-WiMAX converged network scenario show that: in case of TCP traffics for handover from WiMAX to UMTS, not only handover latency and packet loss are eliminated completely, but also abrupt bandwidth/wireless RTT variation is smoothed. These delightful features make this soft handover scheme be a reasonable candidate of mobility management for future mobile converged networks.