• Journal of Advanced Navigation Technology
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• v.10 no.2
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• pp.128-137
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• 2006

Recently, the combination of WLAN and 3G wireless technologies will make MMS service more ubiquitous, bringing benefits to both service providers and their customers. To realize seamless MMS service over WLAN and CDMA2000 networks, we design novel seamless interworking architecture by reusing the existing standards and network elements at the same time. Based on the proposed seamless interworking architecture, we also present seamless notification architecture and seamless handover architecture that can't be possible within current MMS reference architecture. This paper will make a contribution for service providers to provide their customers with seamless MMS service over WLAN and CDMA2000 networks.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.176-179
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• 2002

In recent years, an increasing amount of computer network research has focused on the problem of cluster system in order to achieve higher performance and lower cost. The load unbalance is the major defect that reduces performance of a cluster system that uses parallel program in a form of SPMD (Single Program Multiple Data). Also, the load unbalance is a problem of MPP (Massive Parallel Processors), and distributed system. The cluster system is a loosely-coupled distributed system, therefore, it has higher communication overhead than MPP. Dynamic load balancing can solve the load unbalance problem of cluster system and reduce its communication cost. The cluster systems considered in this paper consist of P heterogeneous nodes connected by a switch-based network. The master node can predict the average execution time of tasks for each slave node based on the information from the corresponding slave node. Then, the master node redistributes remaining tasks to each node considering the predicted execution time and the communication overhead for task migration. The proposed dynamic load balancing uses execution time prediction to optimize the task redistribution. The various performance factors such as node number, task number, and communication cost are considered to improve the performance of cluster system. From the simulation results, we verified the effectiveness of the proposed dynamic load balancing algorithm.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.4
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• pp.1-11
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• 1992

A parallel computer "KAPAC(KAIST Parallel Computer)" based on Transputer is designed and implemented. Its purpose is to support the real time processing and high perfomance computing through parallelizing the complex and heavy computation load. KAPAC has UNIX machine as host-computer and is implemented on VME bus as back-end machine. The parallel computer "KAPAC" is the message-passing loosely-coupled multiprocessor computer having thirty two processing elements, and the network topology between processing elements can be easily configured with the crossbar switchs using the control program. Various topologies are introduced and appoication programs are executed on the parallel computer "KAPAC" with eifferent interconnection topologies to show the reconfigurability.to show the reconfigurability.

• Spatial Information Research
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• v.10 no.3
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• pp.407-419
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• 2002

In this study, the design of 4S-Van system is discussed fur the implementation of laser mapping system. Laser device is fast and accurate sensor that acquires 3D road and surface data. The orientation laser sensor is determined by loosely coupled (D)GPS/INS Integration. Considering current system architecture, (D)GPS/INS integration is performed far performance analysis of direct georeferencing and self-calibration is performed for interior and exterior orientation and displacement. We utilized 3 laser sensors for compensation and performance improvement. 3D surface data from laser scanner and texture image from CCD camera can be used to implement 3D visualization.

• Journal of Technology Innovation
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• v.12 no.2
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• pp.209-225
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• 2004

This study aims to explore and understand the role of knowledge intensive service activities in the industrial innovation of Korea. It analyzes public and private service inputs to the innovation of manufacturers. The contribution of KISs to the innovation of both service suppliers and manufacturers was analyzed by using survey questionnaire. The results of the analysis revealed that the contribution of KISs to the innovation capability of manufacturers is significant. Large manufacturers that hold internal capability to supply KISs are also active in using external KISs. The manufacturing firms that utilized KISs intensively proved to be more innovative than those did not. Heavy KISs users also entertained benefits of capability enhancement as they improved monitoring and achieved efficient application of knowledge asset into product and process innovation. The role of public KISs in the innovation of manufacturers appeared to be indirect and done mainly through education and public R&D activities. Direct input, such as public software service, was not utilized as much in service suppliers themselves. The major reason is that public KISs may not be relevant to their actual needs. Manufacturers have implemented both tighter integration of familiar KISs and loosely coupled unfamiliar KISs.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2007.11a
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• pp.251-255
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• 2007

오늘날 세계화된 시장 환경은 기업간 협업 프로세스의 동적 구성을 요구하고 있으며, 웹 서비스 (Web services)와 비즈니스 프로세스 관리 (Business Process Management) 기술의 발전이 이의 구현을 뒷받침하고 있다. 임의의 기업과의 느슨한 구성(loosely-coupled)을 통한 동적 협업이 활성화됨에 따라, 프로세스의 서비스 품질 (Quality of Service)이 중요한 문제로 대두되고 있는데, 특히 단순한 단위 웹 서비스가 아닌 장기 실행 액티비티 (Long-termed activity)를 포함하는 협업 프로세스에서는 제한된 시간 내에 프로세스의 정상적 수행을 보장하는 것이 핵심적 요구사항이라 할 수 있다. 본 연구에서는 프로세스 수행 계획을 동적으로 생성, 관리함으로써 프로세스의 각 인스턴스들의 완료와 납기 준수를 보장할 수 있는 방법론을 제시한다. 본 방법론은 프로세스 인스턴스의 진행과정에 따라 중복(redundancy) 계획을 동적으로 수정함으로써 각 액티비티의 수행 시간과 신뢰성(reliability)을 독립적으로 관리한다. 본 방법론의 최적화 모델은 NP-hard로 증명되었으며, 본 연구에서는 최적화 모델을 위한 휴리스틱 알고리즘을 제시하고, 이를 실제 최적해와 비교하는 실험을 행하였다. 본 연구를 통해 보다 복잡한 기업간 협업환경에서의 수행 보장과 장애내감성 실현이 가능해 질 것으로 기대된다.

• Journal of Information Technology Services
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• v.10 no.2
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• pp.223-234
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• 2011

Loosely coupled properties of SOA(Service Oriented Architecture) services do not guarantee that service applications always work properly. Service errors may also influence other services of SOA. These characteristics adversely affect software reliability. Therefore, it is a challenge to effectively manage system change and errors for operating services normally. In this study, we propose a SOA based framework using AOP(Aspect Oriented Programming) for reliable service applications. AOP provides a way to manipulate cross-cutting concerns such as logging, security and reliability and these concerns can be added to applications through weaving process. We define a service specification and an aspect specification for this framework. This framework also includes service provider, requester, repository, platform, manager, and aspect weaver to handle changes and exceptions of applications. Independent Exception Handler is stored to exhibited external Aspect Service Repository. When exception happened, Exception Handler is linked dynamically according to aspect rule that is defined in aspect specification and offer function that handle exception alternate suitable service in systematic error situation. By separating cross-cutting concerns independently, we expect that developer can concentrate on core service implementation and reusability, understanding, maintainability increase. Finally, we have implemented a prototype system to demonstrate the feasibility of our framework in case study.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.6
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• pp.516-525
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• 1990

This paper proposes a hierarchical control algorithm for an efficient network management of a loosely-coupled system which consists of functional division and duplicating structure with a LAN to enhance reliability and availability. The algorithm is modeled using the Perti-net and verified with the reachability tree. Here, the proposed algorithm is compared with the purely centralized control algorithm and distributed control algorithm in terms of message traffic for the network management. The result shows that the message traffic related to system performance is as low as centralized control algorithm and the system availability is independent of a specific processor failure.

• The Transactions of the Korea Information Processing Society
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• v.5 no.5
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• pp.1083-1097
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• 1998

The conventional geographic information systems(GIS) is a software which handles spatial and aspatial information of objects in the real world. The system can not support users time-varying information because it manipulates their snapshot data in the spatial database. Also even though it supports time-varying information, it is very limited and hs many difficulties in presenting and processing queries. This paper therefore describes an integrated spatiotemporal data model using loosely-coupled approach which is extended a time dimension for the previous spatial database and which handles time-varying historical information of spatial objects. Conclusionally this paper not only designed a data structure for spatiotemporal database, but also implemented spatial comparison operations varying over time.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.3
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• pp.125-134
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• 2017

The SOA (Service Oriented Architecture) based softwares are escalated because of quickly coping with business requirement. SOA can not apply to existing test method because of loosely coupled service and massage exchange architecture. In this paper, we suggest a method of test case generation using BPMN (Business Process Model and Notation). First we model processes, then make Business Flow Graph (BFG). After searching the euler path through symmetrized BFG about input and output degrees, we generate test cases. A method of test case generation using BPMN can apply at SOA-based system, and reduce the number of test cases.