• Journal of KIISE:Computer Systems and Theory
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• v.31 no.8
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• pp.432-444
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• 2004

In this paper, we construct the TMO-based object group model on distributed environment, and analyze and evaluate the executability for distributed real-time service of our object group model by developing the distributed real-time application simulator applying the model. The Time-triggered Message-triggered Object(TMO) is a real-time server object having real-time property itself. The TMO-based object group is defined as a set of objects which logically reconfigured the physically distributed one or more TMOs on network by a given distributed application. For supporting group management of the server objects, the TMO-based object group we suggested provides the functions which register and withdraw the solver objects as a group member to an arbitrary object group, and also provides the functions which insert and delete the access rights of server objects from clients. Also, our model was designed and implemented to support the appropriate object selection and dynamic binding service for a single TMO as well as the duplicated TMOs, and to support the real-time scheduling service for the clients which are requesting the service. Finally, we developed the Defence System against Invading Enemy Planes(DSIEP) simulator as a practical example of distributed real-time application by applying our model, and evaluated the adaptability of distributed service strategies for the group components and the executability of real-time services that the TMO-based object group model provides.

• Journal of Internet Computing and Services
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• v.11 no.2
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• pp.31-40
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• 2010

In this paper, we propose a service component based on active model for supporting a variety of u-healthcare application services. It implemented that component as a classification of function for developing healthcare application services. Especially we focus on the adaptive information service in integrated environment using a distributed object technologies of the various healthcare home service based on distributed object group framework. And we shows the service component applying to Healthcare application services such as healthcare home monitoring, mobile monitoring and web based monitoring. Also, we show the performance evaluation results such as response time, system load and network load.

• The Journal of the Korea Contents Association
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• v.8 no.4
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• pp.10-16
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• 2008

Quantity of encrypted data that transmitted through the network are increasing by development of encipherment technology. We have many problems; it is caused by technical development and service increase of user requests. It is necessary that create a many encryption key in one web application system. As a result, service quality comes to be low because of increased network traffic and system overload. There must be a system. That should be improved in secure service quality to process data. This paper describes a new approach for design and implementation of distributed encryption key processing for web application system. In this paper, it is based on distributed encipherment key, for the purpose of confidentially, integrity and authentication. It can prevent system degradation from server's data bottleneck and can improve service quality. For distributed encipherment system, we use java object activation technology. It can service while some distributed server are fail.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.6
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• pp.831-835
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• 2010

Currently, engineering design is carried out in a distributed manner geographically or physically. This imposes new requirements on the computational environments, such as efficient integration and collaboration in the Internet and network environments. Meanwhile, Web-based distributed design has led new paradigms in design and manufacturing fields. For example, Web-based technologies have reduced the product development time and to ensure a competitive product in order to exchange and interact of real-time design information that integrates the distributed design environment between departments as well as companies via Internet and Web. Hence, efficient data communication for design information sharing is the basis for collaborative systems in the distributed environments. Design data communication techniques such as CORBA, DCOM, and JAVA RMI have been considered in the existing research, but these techniques have some disadvantages such as limitations of interoperability and firewall problems. This paper presents the application of engineering design problems in which distributed design information resources are integrated and exchanged using Web Service for supporting XML and HTTP without interoperability and firewall problems.

• Journal of the Korea Society for Simulation
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• v.12 no.3
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• pp.83-94
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• 2003

For 24 hours-7 days service on distributed systems, a great deal of efforts are investigated on high availability for seamless operation. In this paper, we propose a dynamic reconfiguration framework of distributed systems, called "hot-swapping" framework. This framework allows us to upgrade and exchange a number of modules of a distributed system without stopping running service as well as the system itself. In order to hide the state of service operation, the framework employes the "proxy" design pattern. Our framework provides two types of proxies: a static proxy and a dynamic proxy, Static proxies can achieve fast execution time, but they need to be changed whenever any minor change exists in the related swappable module. Meanwhile, dynamic proxies takes longer execution time, but do not need to be changed under minor changes of swappable modules. We compare performances of static and dynamic proxies and also apply the framework to a real situation with security management modules. management modules.

• The Transactions of the Korea Information Processing Society
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• v.7 no.4
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• pp.1050-1061
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• 2000

This paper presents a new object model, LOM(Lightweight Object Model) and an implementation method for the distributed trader in heterogeneous distributed computing environment including mobile network. Trader is third party object that enables clients to find suitable servers, which provide the most appropriate services to client in distributed environment including dynamic reconfiguration of services and servers. Trading service requires simpler and more specific object model than genetic object models which provide richer multimedia data types and semantic characteristics with complex data structures. LOM supports a new reference attribute type instead of the relationship, inheritance and composite attribute types of the general object oriented models and so LOM has simple data structures. Also in LOM, the modelling step includes specifying of the information about users and the access right to objects for security in the mobile environment and development of the distributed storage for trading service. Also, we propose and implementation method of the distributed trader, which integrates the LOM-information object model and the OMG (object Management Group) computational object model.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2007.02a
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• pp.139-151
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• 2007

Decision-making in the crisis management happens in dynamic, rapidly changing, and often unpredictable distributed environments. Crisis management Decision Support Systems (DSSs) in E-Government are challenged by the need to use it availably at anytime, from anywhere, and even under any-situation. In this paper the reasons of developing distributed architecture for crisis management Decision Support Systems (DSSs) in E-Government are analyzed. Consequently, a distributed architecture for crisis management Decision Support System (DSS) is proposed in this paper. Finally it is implemented by Web Services. If crisis management Decision Support System (DSS) based on distributed architecture is implemented by Web Service, then it can provide decision support for decision-makers to deal with crisis at anytime, from anywhere, and even under any-situation.

• Journal of Digital Contents Society
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• v.4 no.2
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• pp.181-189
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• 2003

The requirement of distributed multimedia applications is the need for sophisticated QoS(quality of service) management. In terms of distributed multimedia systems, the most important catagories for quality of service are a timeless, volume, and reliability In this paper, we discuss a method for increasing reliability through fault tolerance. We describe the design and implementation of the ECA running on distributed multimedia environment. ECA is a system is able to classify automatically a software error based on distributed multimedia. This papaer explains a performance analysis of an error classification system running on distributed multimedia environment using the rule-based DEVS modeling and simulation techniques. In DEVS, a system has a time base, inputs, states, outputs, and functions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.5
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• pp.897-905
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• 2007

In this paper, we present a new framework and synchronization mechanism to effectively support developing real-time communication service by using a real-time object model named TMO (Time-Triggered Message-Triggered Object). Also, we describes the application environment as the DHS(distributed high-precision simulation) to guarantee real-time service message with TMO structure in distributed network systems. The TMO scheme is aimed for enabling a great reduction of the designer's effort in guaranteeing timely real-time communication service capabilities of among distributed multi-nodes systems. Our real-time framework provide the consistent construction and configuration of tine-triggered processing components across heterogeneous distributed object environment more easily. It has been formulated from the beginning with the objective of enabling design-time guaranteeing of timely action. In the real time simulation techniques based on TMO object modeling, we have observed several advantages to the TMO structuring scheme. TMO object modeling has a strong traceability between requirement specification and design.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3B
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• pp.225-234
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• 2009

Recently IPTV service is penetrating to the ordinary home users very swiftly. One of the first phase of IPTV service is considered to be VoD, and a nationwide availability of the VoD service imposes tremendous pressure to the network resource due to its requirements for the broad bandwidth, the inherent nature of unicast technology, and the large scalability, etc. This work suggests a novel and practical method to the design of network resource for the VoD service. Especially, we explore the distributed content storage problem that takes into account the popularity of the video contents and its corresponding link dimensioning problem that takes into account the grade of service for the flow level quality of service about the VoD service. By assuming a realistic topology for the nationwide IP backbone network of Korea, which is a typical tree topology, we suggest an analytic method for the design of VoD service.