• 디자인학연구
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• 제17권1호
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• pp.49-62
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• 2004

무선인터넷으로 상호작용 하는 정보를 다양한 그래픽으로 가시화하면서 인터페이스를 통일화한 무선인터넷 단말기용 GUI (Graphic User Interface)가 사용자의 선택의 폭을 확장하고 감성만족도 향상에 크게 기여한다는 점에서 매우 고무적인 기술적 진전으로 받아들여지고 있다. 특히 최근 무선인터넷 단말기의 해상도와 색상이 높아지면서 사용상의 편의성과 시각효과를 강조한 GUI를 요구하고 있어 향후 이 분야의 연구가 크게 증가할 것으로 전망된다. 모바일 컴퓨팅의 인터페이스는 사용자들의 미감과 정보효율성에 중요한 영향을 미칠 것이다. 현재 국내 상황은 무선인터넷업체와 GUI 디자인업체가 핸드폰 PDA 스마트폰 등 무선인터넷 단말기를 통일된 사용방법으로 작동하면서 다양한 그래픽 화면을 처리할 수 있게 해주는 GUI개발에 전력하고 있다. 사례연구에서는 Nokia 3650 모델과 MS의 Orange SPV 모델이 제공된다. 이 두 모델의 사용성 비교평가를 통해 PDA와 Phone이 결합된 형식의 차세대 스마트폰 UI 개발에 벤치마킹하고자 한다. 2535세대의 취향에 맞는 유저빌리티 개발을 중심으로 WIPI WAP 메뉴를 구성 하고, WAP서비스 및 VM Browser, PDA Browser개발을 위한 연구 자료로 활용할 수 있으며 사용자의 디자인 선호도 분석을 통해 WAP 메뉴로의 접근성을 감성적으로 강화시키고자 함이 본 연구의 목적이다. 본 연구에서 제시하는 평가모형은 무선인터넷단말기를 개발하는 개발자, 디자이너, 기획자들에게 보다 효과적인 인터페이스 분석 자료를 제공하며, 스마트 폰 개발 시 고려해야 할 Check point 제시를 통해 WIPI 폰의 GUI Guideline으로의 활용을 기대한다.

• 전자공학회논문지CI
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• 제48권3호
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• pp.76-81
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• 2011

침입방지시스템은 내부 시스템 보안 또는 외부 공격의 문제를 해결하기 위한 중요한 솔루션이다. 이러한 침입방지시스템을 도입 시 가장 우선적으로 고려해야 될 사항으로는 다양한 기능보다 안정성이다. 본 논문은 침입방지시스템 보안모델의 사용자 인증기능에 대한 안정성 검증을 위하여 칼라 페트리 네트를 이용하였다. CPN은 분산되어있고, 동시 발생적이며, 결정적 또는 동기화 방식의 비결정적인 시스템들에 대하여 그래픽적인 모델링 언어로 표현이 가능하다. 이런 칼라 페트리 네트는 각 처리 단계에 대하여 모든 가능한 상태와 발생 그래프로 표현된다. 침입방지시스템 보안 모델의 안정성은 칼라 페트리 네트를 이용한 모든 상태표현과 발생그래프의 분석결과가 무한반복 혹은 교착상태가 없으므로 검증되었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권3호
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• pp.921-940
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• 2015

In this paper, we investigate the multi-resource allocation problem, a unique feature of which is that the multiple resources can compensate each other while achieving the desired system performance. In particular, power and time allocations are jointly optimized with the target of energy efficiency under the resource-limited constraints. Different from previous studies on the power-time tradeoff, we consider a multi-server case where the concurrent serving users are quantitatively restricted. Therefore user selection is investigated accompanying the resource allocation, making the power-time tradeoff occur not only between the users in the same server but also in different servers. The complex multivariate optimization problem can be modeled as a variant of 2-Dimension Bin Packing Problem (V2D-BPP), which is a joint non-linear and integer programming problem. Though we use state decomposition model to transform it into a convex optimization problem, the variables are still coupled. Therefore, we propose an Iterative Dual Optimization (IDO) algorithm to obtain its optimal solution. Simulations show that the joint multi-resource allocation algorithm outperforms two existing non-joint algorithms from the perspective of energy efficiency.

• 한국IT서비스학회지
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• 제10권4호
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• pp.119-131
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• 2011

When your company buys packaged software, the company needs to determine how many software licenses must be purchased. If the quantity is too small, it will be not enough for the users to access the programs at anytime within the company. Conversely, if the quantity is too large, they will waste a lot of money. In this paper, we surveyed several number of researchers of K institute and derived the using pattern of a specific packaged software. We estimated a proper number of packaged software licenses by Erlang Loss Function, the Engset Model, and simulation model. With the results of the three methodologies, we were able to empirically verify economic benefits of packaged software purchase by comparing NPV (Net Present Value) between user licenses and network licenses. Consequently, TCO of user licenses is much higher than that of network licenses. We had probabilistically calculated proper number of licenses based on the using pattern of users. Hence, this paper will be useful for decision makers who are going to determine package software's type and quantity from an economic perspective.

• 컴퓨터교육학회논문지
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• 제5권4호
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• pp.79-89
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• 2002

기존의 고정 단발기 (PC)에서만 주로 행해지던 각종 다중 사용자 접속 온라인 응용이 최근 PC와 PDA, 휴대폰 등이 공동 작업을 수행하는 멀티 플랫폼 기반 온라인 응용으로 전환되고 있다. 그러나 지금까지 멀티 플랫폼 기반 온라인 응용은 다중 사용자의 공동 데이터의 동시 접근 및 각 클라이언트의 처리 능력과 통신 속도의 비대칭을 고려하지 않아 컨텐츠가 매우 단순한 실정이다. 이 논문에서는 멀티 플랫폼 기반 동시성 제어 기법, 다양한 클라이언트간의 변경 전파 프로토콜, 모바일 클라이언트의 특성을 고려한 객체 관리 기술을 제안하였다. 그리고 멀티 플랫폼 기반 채팅 프로그램을 제작하여 제안한 기법들이 적절히 동작함을 보였다.

• 한국통신학회논문지
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• 제27권4C호
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• pp.282-294
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• 2002

The modern telecommunication networks are composed of various network-type and are managed by various management technologies, such as TMN, SNMP, TINA etc. Furthermore, the network user's needs of real-time multimedia services are rapidly increasing. In order to guarantee the user-requested quality-of-service(QoS) and keep the network utilization at maximum, it is required to manage the network performance continuously after the network is deployed. The performance management function should provide the useful information for the network expansion and the capacity reallocation in the future. In this paper, we propose a DPE-based performance management architecture for the integrated management of the heterogeneous network elements with TMN and SNMP. We propose an approach to provide the Intranet traffic monitoring and analysis function using layered network management concept and distributed processing technology. The proposed architecture has been designed and implemented based on multiprocess and multithread structure to support concurrent processing. To manage the traffic according to the Intranet service categories, we implemented an ITMA(Intelligent Traffic Monitoring Agent) with packet capture library. With the proposed architecture, we could measure and analyze the real Intranet traffic of Yeungnam University.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.913-918
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• 2008

When developing railway vehicle system, investigation of the dynamical stability is essential as a virtual prototyping process. Not only the verification using the commercial analysis tools, systematic analysis using customized tools is also necessary, because these can give other points of view in stability, which is sometimes unable to evaluate in the former one. As a solver platform for customization, it is important to derive basic theory about flexible bodies and build flexible structure, which enables easy module insertion of user-created functions. In the paper, a flexible dynamic analysis system is developed, using absolute cartesian coordinate, modal coordinate and absolute nodal coordinate. Each coordinate system is verified by respective examples for every system. This solver system will play an important role for building the basic platform for analysis system, keeping pace with the concurrent development of the modules, such as wheel-contact force, constraints and user-defined force modules. Using the information from the analysis, the evaluation of the dynamic behavior of the train and its stability analysis will be available.

• 품질경영학회지
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• 제18권2호
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• pp.54-68
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• 1990

Contingency response in a FMS system requires that the system be able to identify and evaluate a number of alternatives. This paper is outlined that DSS completes with a problem processor in corporating Timed Petri Nets model, and a data base system. DSS enables the FMS user to get the maximum benefit from a FMS. The structure of this DSS parallels the organizational activities involved in running the FMS. In designing a shop floor controller for FMS, interactions between the different real time, discrete event functions must be established. The specification of the machine tool and material handling system functions working as a concurrent and cooperative system is given in terms of Timed Petri Nets. In addition, the basic concepts and uses of Petri Nets are surveyed. The system to be studied is first modelled by a Timed Petri Nets and then procedure for evaluating the FMS system performance are presented. Numerical examples are studied to illustrate a session of the FMS used-DSS interaction.

• 한국CDE학회논문집
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• 제4권3호
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• pp.200-209
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• 1999

This paper presents a 3D-conferencing system as a prototype implementation of concurrent and distributed engineering environment using CORBA-Java and SDAI-Java. The system consists of some client and server objects that communicate with each other via ORB. The server objects use lightweight version of current working draft of SDAI-Java to access STEP product data models, and the client objects provide user-friendly graphical interface. The proposed system can be used for communicating with 3D CAD data between remote designers, manufactures and customers regardless of he H/W or S/W platforms they use.

• ETRI Journal
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• 제34권5호
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• pp.759-762
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• 2012

Carrier aggregation is an essential feature in the Long Term Evolution-Advanced (LTE-A) system, which allows the scalable expansion of the effective bandwidth to be delivered to user equipment (UE) through the concurrent use of radio resources across multiple component carriers (CCs). This system's optimal radio-resource use has received much attention under simultaneous access (SA) scenarios for multiple CCs (m-CCs). This letter establishes how many CCs a UE should simultaneously connect to maintain maximum uplink capacity. Under the m-CC LTE-A system, the spectral efficiency of the m-CC SA scheme ($m{\geq}2$) is compared with that of CC selection (CCS). Numerical results reveal that the 2-CC SA scheme outperforms CCS and performs almost equally to the m-CC SA scheme ($m{\geq}3$).