• Journal of Digital Contents Society
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• v.8 no.1
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• pp.1-8
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• 2007

Recently, As the increase in interaction between the person and the person, the people plentifully use a messenger. Thus, we propose a new messenger program, we call Hellow Fellow Messenger. The hollow fellow messenger has functions of general messenger such as chatting, note exchange, friend addition. Also, hollow fellow messenger provide with special function, which find friends satisfied conditions in PDA and PC environment. So, Client can find not only friend who is register already but also friend who is the possibility of seeing a movie and can comfortably talk together and so on. For this, server sends information for users satisfied in condition from databases to client and client selects a user among received information for users. Client-server communication is implemented using MFC[1].

• The KIPS Transactions:PartD
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• v.8D no.3
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• pp.221-232
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• 2001

Due to rapid advance of wireless communication technology, demand on data services in mobile environment is gradually increasing. Caching at a mobile client could reduce bandwidth consumption and query response time, and yet a mobile client must maintain cache consistency. It could be efficient for the server to broadcast a periodic cache invalidation report for cache consistency in a cell. In case that long period of disconnection prevents a mobile client from checking validity of its cache based solely on the invalidation report received, the mobile client could request the server to check cache validity. In doing so, some schemes may be more efficient than others depending on the number of available channels and the mobile clients involved. In this paper, we propose new cache consistency schemes, effects, efficient especially (1) when channel capacity is enough to deal with the mobile clients involved or (2) when that is not the case, and evaluate their performance.

• Journal of Digital Convergence
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• v.11 no.9
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• pp.201-207
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• 2013

Recently, the interest in a Mobile Office is increasing dramatically and the Smart Phone App Service begin in earnest to be requested in an area of applying SAP system to PC. This study aims to research the system which can be easily implemented with the configuration and Mobile App which cause difficulties in embodying SAP system-based Apps suitable for a mobile environment. First, by realizing SAP system interface that can operate in mobile devices in the form of GUI, assisting the connecting parts of SAP for the users-friendly set-up, providing the communication method of Client, Application, and SAP Service in the form of web service through TCP/IP, and finally showing cases of implementing the method of delivering the data request and result value of Server and Client in the form of XML suggest more effective and new method, the research suggests a new way of making the linkage of SAP more efficient.

• Journal of The Korean Association of Information Education
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• v.3 no.2
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• pp.113-119
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• 2000

I studied a distance education model for English learning on the Internet. Basic WWW files, that contain courseware, are constructed with HTML, and functions, which are required in learning, are implemented with Java. Students and educators can access the preferred unit composed of the appropriate text, voice and image data by using a WWW browser at any time. The education system supports the automatic generation facility of English problems to practice reading and writing by making good use of the courseware data or various English text resources located on the Internet. Our system has functions to manage and control the flow of distance learning and to offer interaction between students and the system in a distributed environment. Educators can manage students' learning and can immediately be aware of who is attending and who is quitting the lesson in virtual space. Also, students and educators in different places can communicate and discuss a topic through the server. I implemented these functions, which are required in a client/server environment of distance education, with the use of Java. The URL for this system is "http://park.taegu-e.ac.kr" in the name of GAIA.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.697-701
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• 1995

The network encironment includes a number of autonomous agents which are widely distributed, have different platforms, and change very dynamically. The information system operated on this environment must solve some basic problems; restrictive client-server models, heterogeneous systems, and intellignet agents. We are using KQML for knowledge management. Java language provides solutions against a strong server dependency and a heterogenous troubles. We introduce KQML as an agent communication language and JATLite as a java agent template. these increase an efficiency of communication on network and enable us to use resources distributed in world wide web. Also, we describe a new agent system architecture and implement it through an example scenario

• Korean Institute of Interior Design Journal
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• no.22
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• pp.132-138
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• 2000

Internet services are utilizing a variety of server/client technologies. In particular internet technologies provide improved accessibility to information for facility management customers and users for the systems. This study is the architectural data exchange system development more effective management and accept using on Internet web environment. This paper is the explore the use of computers in architectural planning that how the information may be extracted drawing entered into database and exchanged architectural detail data interfaces. System support communication and interactive collaboration among designers through complex Building object during the Design. There are four part in collaborative design system. User Management system, Standard Database System, Project Database System and Interface system. All Data are recognizable format include drawing file and contents. Web/DB server supported communication and collaboration among partners in the building design and construction process. Collaborative Design system is provide new conceptual framework that exist in the Web.

• 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 Association of Information Education
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• v.1 no.2
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• pp.67-83
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• 1997

We studied a CAI courseware model for distance education on network, with the use of Java language. Basic www files, contents of courseware, are constructed with html. Students and educator can access the preferred unit composed of the appropriate multimedia data by using of www browser at any time. The distance education system, in this paper, has functions to manage the flow of distance learning, and to offer interaction between students and system in distributed environment. Students and/or 'educator can discuss a topic through server in different places. We implemented these functions, which are required in server and client environment of distance education, with the use of Java.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.766-769
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• 2000

In recent years, Internet/Intranet represents the next generation of computing environment. Therefore, it is necessary to integrate WWW((World Wide Web) over internet/intranet and DBMS(Database Management System) in proportion to the increase of various users' request and an amount of data variety. Also, also full variety of service over WWW need to accomplish rapidly modification of bug and make a betterment of system according to a feature of rapid change of information and an importance of interaction with users. The typical CGI method commonly used to connect with database has a disadvantage in time and resources in system due to frequent connection with database. Therefore, this paper provides the conceptual structure and implementation of information management system over WWW with applying a recent information technology called ASP(Active Server Pages) that controls and arranges client logic dynamically in server-side and introducing a concept of working group and folder to database design.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.364-367
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• 2000

As computer system and information/communication technology develop rapidly, nowadays CSCW(Computer Supported Collaborative Work) system appears, through which it is available to work on virtual space without any restriction of time and place. Most of Un systems depend on a special network and groupware. The systems of graphics and CAD are not so many because they are characterized by Hardware and application software. In this paper, we propose a web-based collaborative CAD system which can be jointly worked on Internet WWW being independent from any platforms. It can generate and handle objects easily using lava 3D, and it can transmit, print, and store them. The interactive work for designing objects can be also carried out through dialling with each other. This system is executed in the environment of Client/server. Clients connect to the server through lava applet on WWW. The server is implemented by lava application, and it consists of three components : connection manager which controls the contact to users, work manager which keeps viewing in concurrency and provides virtual work space sharing with others, and solid modeler which generates 3D object.