• Proceedings of the Korean Operations and Management Science Society Conference
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• 1998.10a
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• pp.182-185
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• 1998

In the two-tier CDMA cellular system with microcells and overlaying macrocells, slow-moving mobile user are assigned to microcells and those who move fast are assigned to overlaying macrocells in order to minimize the total number of handoffs. With this consideration the problem is how to find the thresholds by which the system distinguishes fast-moving user from those who move slowly based on the estimated speed of users. In this paper, two methods for the mobile speed estimation are proposed and two operations schemes for micro-macro cellular CDMA system are suggested. Based on these, Optimization models to find the optimal thresholds for micro-macrocell selection, which are subject to the constrains of QoS, are developed in view of minimizing the weighted total number of handoffs. And then algorithms to find optimal solutions of the models are devised.

• Journal of the Korean Society for information Management
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• v.19 no.3
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• pp.49-68
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• 2002

The purpose of this paper is to examine the evaluation models of internet sites and to analyze the factors affecting the consumer satisfaction of health information sites in the Internet. Based on the covariance structural model applied to a customer survey, this study shows that among the characteristics of the site. contents has the most significant effect on customer satisfaction, which in turn affects the consumer willingness to recommend the site to others.

• Electronics and Telecommunications Trends
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• v.26 no.6
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• pp.129-138
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• 2011

미래의 고속 및 광대역 서비스에 대한 수요 증가로, 부족한 스펙트럼을 효율적으로 사용할 수 있는 스펙트럼 관리(spectrum management) 방법의 중요성이 대두되고 있다. 또한, 트래픽 폭증 및 멀티미디어 제공 등 서비스 확대에 대응할 수 있는 유연한 스펙트럼 접속(spectrum access) 기술, 공유(sharing)에 대한 필요성도 증대되고 있다. 이러한 중요성 및 필요성에 기인해, 효율적으로 스펙트럼을 공유할 수 있는 방법으로 언더레이, 오버레이 방식 등이 제안되었고, UWB 및 인지무선(cognitive radio)과 같은 공유 기술 등이 발전하게 되었다. 본 고에서는 효율적 주파수 이용을 위한 스펙트럼 관리 방법 및 주파수 공유 기술로 기존의 주파수 대역에서 충분히 낮은 출력으로 전파를 송출하는 언더레이 방식, 기회주의적인 오버레이 동적접속 기술, 면허권자인 1차 우선 사용자(primary user)와 2차 면허권자(secondary user) 간의 동적접속 기술에 대한 국내 외 기술동향을 상세히 소개하고자 한다.

• Journal of the Korea Society of Computer and Information
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• v.17 no.11
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• pp.125-132
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• 2012

In recent years, a variety of learning content construction utilizing the smart phone is coming. In this paper, we investigate on overall trends and movements in e-learning performance at University. And system developed a e-learning platform consisting of smart phone portal, learning management system(LMS), and learning content management system(LCMS). Throughout the experiment, each of the components of the e-learning were implemented. LMS was implemented more efficiently using a user profile evaluation system for qualification.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.10
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• pp.139-158
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• 1999

This study is concerned with analysis of user satisfaction for travel behavior. It is aimed at investigating the socioeconomic characteristics, motivation, and use pattern of the visitors at tour. For tourists' perception and preference analysis, multi-dimensional scaling was used. It is left that this type of marketing analysis of tourism and travel offers great potentional for those concerned with the developement and management of tourist vacation areas. First, the study demanstrated clearly that different tourist and portential visitors to a tourist area seek different benefit bundles from their vacation in a particular tourist areas. Second, it demonstrated that a benefit segmentation approach to tourism and travel would be the most effective that the demographic segmentation approach usually pursued in the tourism and travel industry. Form a methodological viewpoint, it has demonstrated an application of multidimensional scaling techniques to marketing in an important industry.

• Journal of Korean Society for Quality Management
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• v.23 no.2
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• pp.1-9
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• 1995

Two user groups, expert and non-expert, are sampled to measure the image quality of G3 facsimile. A ITU-TS tset chart No. 2 has been transmitted among some selected cities and evaluated by user groups. Their subjective evaluation to the image quality is quantified by Mean Opinion Score method. There is highly significant difference in the image quality between expert and non-expert. From modified logit model, it is concluded that there is no significance in two considered factors, the effects of the number of links and transmission time. The derived percent curves show that 80% of non-experts(90% of expert) is considering the image quality of G3 facsimile "fair, good, or excellent".

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1990.04a
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• pp.81-90
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• 1990

The major objective of this paper is to analyze the relationships between End-User Computing(EUC) attributes and its implementation. Reviewing the related literatures, we categorized EUC attributes into threefactors - relative advantage, compatibility, complexity. With such attributes this paper proposed a hypothetical model which explains the effect of the EUC attributes on its implementation. Under the assumption that EUC attributes affect its implementation differently according to the several contingent factors, the model included such factors as organizational size, organizational support level on the EUC activities and individual characteristics - computer experience, education level, age. Data were collected form 177 end-users of 40 Korean business firms. Hypotheses were tested using Pearson Correlation, t-test, ANOVA and the results are discussed below.

• Journal of Information Processing Systems
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• v.5 no.1
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• pp.19-24
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• 2009

Many researchers have developed frameworks that are capable of handling context information and can be adapted and used by any Web service. However, no research involving the systematic analysis of existing frameworks has yet been conducted. This paper examines the Context Framework, an example of existing frameworks, using a Petri net, and analyzes its advantages and disadvantages. Then, a Petri net model - with its disadvantages removed - is introduced, and a new framework is presented on the basis of that model. The proposed PAWS (Privacy Aware Web Services) framework has a expendability for context management and communicates flexible context information for every session. The proposed framework can solve overhead problems of context in SOAP messages. It also protects user privacy according to user preferences.

• Journal of Information Processing Systems
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• v.9 no.3
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• pp.489-498
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• 2013

In this paper, we propose a common simulation model that can be reused for different performance evaluations of networked virtual environments. To this end, we analyzed the common features of NVEs, in which multiple regions compose a shared space, and where a user has his/her own interest area. Communication architecture can be client-server or peer-server models. In usual simulations, users move around the world while the number of users varies with the system. Our model provides various simulation parameters to customize the region configuration and user movement pattern. Furthermore, our model introduces a way to mimic a lot of users in a minimal experiment environment. The proposed model is integrated with our network framework, which supports various scalability approaches. We specifically applied our model to the interest management and load distribution schemes to evaluate communication overhead. With the proposed simulation model, a new simulation can be easily designed in a large-scale environment.

• Journal of the Korean Society for information Management
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• v.14 no.2
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• pp.165-189
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• 1997

In analyzing, designing, implementing the system, the traditional modeling method lacks design procedure and specification in reflecting the functional or nonfunctional requirements perfectly and consequently. These problems are unreliable in the Library and Information System since it requires a diversity of reference methodes based on various types of data. In this paper, we modify the method partially which the OMT proposes and apply it on system development. We also prepare the object oriented modeling modified from OMT type' modeling for Library User System Requirements.