• Journal of KIISE:Information Networking
• /
• v.31 no.5
• /
• pp.460-468
• /
• 2004

Quality of Service (QoS)-constrained policy has an advantage to guarantee QoS requirements requested by users. Quorum systems can ensure the consistency and availability of replicated data despite the benign failure of data repositories. We propose a Quorum based resource management scheme, which includes a system resource and network resource, both of which can satisfy the requirements of application QoS. We also propose the resource reconfiguration algorithm based on temporal execution time estimation method. Resource reconfiguration means that reshuffling the current available resource set for maintaining the quality level of the resources. We evaluate the effectiveness of resource reconfiguration mechanism with a Heart Hemodynamics analysis. Our approach shows the increase of the stability of execution environment as well as decrease the completion time compare to the method that is not adapted the resource reconfiguration.

• Journal of KIISE:Computing Practices and Letters
• /
• v.11 no.6
• /
• pp.465-476
• /
• 2005

In this paper, we propose a new dynamic reconfiguration method using application-level checkpointing in a grid computing environment with Cactus and Globus. The existing dynamic reconfiguration methods have been dependent on a specific hardware and operating system. But the proposed method performs a dynamic reconfiguration without supporting specific hardwares and operating systems and, an application is programmed without considering a dynamic reconfiguration. In the proposed method, the job starts with an initial configuration of Computing resources and the job restarts including new resources dynamically found at run-time. The proposed method determines whether to include the newly found idle sites by considering processor performance and available memory of the sites. Our method writes the intermediate results of the job on the disks using system-independent application-level checkpointing for real-time visualization during the job runs. After reconfiguring idle sites and idle processors newly found, the job resumes using checkpointing files. The proposed dynamic reconfiguration method is proved to be valid by decreasing total execution time In K*Grid.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2011.11a
• /
• pp.175-176
• /
• 2011

협업 컴퓨팅 환경은 컴퓨팅, 네트워크 자원을 통하여 연구자들간의 협력을 하는 일련의 작업 과정을 의미한다. 사람이 포함되어 있는 복잡한 연구환경에서 워크플로우 기반의 작업 수행은 협업환경을 위해 유용하게 사용된다. 하지만 자원의 예기치 못한 자원의 성능 저하는 전체 워크플로우의 성능을 저하시키게 된다. 본 논문에서는 워크플로우 자원 스케줄링에 있어서 최초에 결정되어 할당된 자원을 재배치 시키는 재구성 기법을 통하여 워크플로우 응용의 성능 저하를 개선하고자 한다.

• Journal of KIISE:Information Networking
• /
• v.34 no.2
• /
• pp.120-133
• /
• 2007

A multicast tree includes several, possibly a large number of, paths connecting source-receiver pairs, and network failure may disable part of the multicast tree. Reconstruction of the entire multicast tree to recover from a component failure is highly undesirable, because some group members have to suffer service disruptions even though the communication paths to/from them are not affected by the failure. To limit reconfiguration region and to maximize the likelihood of successful reconfiguration, we propose and evaluate a pre-planned reconfiguration policy for QoS multicast sessions. Specifically, we equip a reconfiguration path (RP) with each end-to-end path that connects a source-receiver pair in the multicast tree, and reserve resources in advance along the RPs. Efficient resource-sharing techniques are applied to reduce the amount of resources reserved for RPs but not used in the absence of failures. This way, we prevent uncontrolled competition among different multicast sessions which may simultaneously try to recover from failures. We evaluate the performance of the proposed scheme using simulation on randomly-generated networks. We use the shortest-path routing for QoS multicast sessions, and simulate both source-based and shared multicast trees. The evaluation results indicates that successful pre-planned reconfiguration can be achieved for all group members with reasonable overhead. Our scheme is also shown to adapt well to dynamic changes of group membership.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.15 no.4
• /
• pp.175-192
• /
• 2020

This study analyzed the effects of corporate dynamic capabilities on enterprise performance by using ambidextrous innovation activities as mediators, focusing on SME employees. The sub-variables of dynamic capabilities were divided into opportunity exploration capability, resource acquisition capability, and resource reconstruction capability. 282 questionnaires collected from small and medium-sized enterprises residing in the metropolitan area were used for empirical analysis. SPSS v22.0 and Process macro v3.4 were used to analyze the parallel multiple mediation model. First, the results of the analysis showed that opportunity exploration capability, resource acquisition capability had a positive (+) effect on the ambidextrous innovation activities, and the effect of resource reconstruction capability on ambidextrous innovation activities was not significant. Second, the ambidextrous innovation activities had a significant effect on the enterprise performance. Third, it was found that opportunity exploration capability and resource acquisition capability had a positive (+) effect on enterprise performance, and the effect of resource reconstruction capability on enterprise performance was not significant. Fourth, the ambidextrous innovation activity mediated the relationship between opportunity exploration capability and enterprise performance. Fifth, the ambidextrous innovation activity mediated the relationship between resource acquisition capability and enterprise performance. Sixth, the ambidextrous innovation activity did not mediate the resource reconstruction capability and the enterprise performance. As a follow-up study, it is necessary to find third mediators besides the mediators used in this study, analyze the serial mediation model through these, and study for the moderated mediation analysis through the conditional process model in which the moderator is introduced.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.7A
• /
• pp.1170-1181
• /
• 2001

본 논문은 다양한 실시간 스케줄링 알고리즘과 자원 접근 제어 정책을 통합적으로 설계/구현하되 필요에 따라 시스템을 선택적으로 재구성할 수 있게 하는 통합 실시간 스케줄링 모델을 제안한다. 제안 모델은 [3, 4]에서 제안된 기존 모델에 자원 관리자 및 대기 큐 관리자가 추가되었다. 사용자는 태스크 및 자원 속성을 기반 스케줄링 알고리즘에 상관없이 동일하게 지정할 수 있다. 반면 시스템 설계자는 우선순위 역전 문제를 해결하고 공유 자원에 대한 한정된 블록킹 시간을 보장하기 위한 다양한 자원 접근 제어 정책들을 하위 단계의 복잡한 커널 모듈을 수정하지 않고도 효율적으로 개발할 수 있다. Real-Time Linux [6]에 제안된 스케줄러 모델을 구현한 후, 이를 기반으로 다양한 스케줄링 알고리즘과 자원 접근 제어 정책들을 시험적으로 구현하여 보았다. 여러 성능 실험을 통해 제안 모델을 기반으로 다양한 알고리즘과 정책을 구현한다 해도 실행시의 오버헤드는 크지 않은 반면, 시스템 재구성과 자원 접근 제어 정책을 효과적으로 지원할 수 있다는 것을 확인할 수 있었다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2007.06b
• /
• pp.148-151
• /
• 2007

소프트웨어가 해결해야 할 문제가 점점 복잡해지고 있음과 동시에 소프트웨어의 자체의 복잡도 또한 증가하고 있다. 또한 소프트웨어 개발 시간에 예상하지 못했던 실행 환경에 노출되는 경우가 빈번해 졌다. 이러한 요구상항과 함께 소프트웨어의 유지보수와 개발을 쉽게 하기 위해 자가 적응형 소프트웨어에 대한 필요가 늘어나고 있다. 자가 적응형 소프트웨어란 실행 환경과 내부 상황을 판단하여 적절한 기능을 수행할 수 있도록 스스로 재구성 할 수 있는 소프트웨어이다. 소프트웨어가 향상된 기능으로 재구성을 하려면 자신의 내부 상황과 자원 소모량 등 소프트웨어 실행 환경에 대한 계속 적인 관찰이 필요하다. 그러나 기존의 자원 소모량 관찰에 대한 연구는 개발 시간에 프로그램 자체 효율을 위해 프로그램 개발 언어 단위에서 이루어져왔다. 예를 들면 관찰 단위가 실행시 호출되는 함수나 데이터 중심으로 진행 되어 재구성 단위인 컴포넌트 별로 이해하기가 쉽지 않았다. 따라서 본 논문은 재구성 단위를 컴포넌트로 정의 하고 메소드 단위의 호출이 생길 때마다 발생하는 데이터를 컴포넌트 단위로 추상화 시키는 기법을 제안한다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.19 no.11
• /
• pp.2199-2214
• /
• 1994

In order to sufficiently utilize the potential effectiveness of ATM networks, systematic and effective network management and control systems must be employed. In addition to network design, planning, and call routing techniques used in traditional circuit-switched networks. ATM networks can provide logical VP(Virtual Path) reconfiguration capabilities which can adapt to changes in the network environment. With a proper application of the VP reconfiguration technique, ATM networks can reduce the overhead of frequent network redesign and the overhead of call routing processing. However, ATM VP reconfiguration is a very complex and difficult problem which consists of many facets of optimization subproblems such as VP routing. VP sizing, VP terminating point location and VC routing. Most previous research on the ATM logical network reconfiguration problem dealt with the subset of the problem. This paper mathematically formulates the ATM network reconfiguration problem completely considering all subproblems. Since it is very difficult to derive the optimal solution of the formulated problem, we develop a heuristic method based on a Max min bandwidth allocation principle. We show the feasibility of the proposed heuristic method with a simple example.

• Proceedings of the Korean Information Science Society Conference
• /
• 2005.07a
• /
• pp.28-30
• /
• 2005

센서들은 제한된 자원으로 구동되므로 오류가 나기 쉽다. 특히 구조적 라우팅의 경우 클러스터 헤드의 오류시 많은 수의 센서가 네트워크에서 분리되어 네트워크 성능에 악영향을 미친다. 따라서 오류 처리에 관한 연구들이 이루어져 왔으나 기존의 연구들은 망을 최적으로 유지하기 위해 재구성시 전체 네트워크를 재구성 하며 고정된 주기를 사용하여 전체적인 망이 최적의 상태임에도 불구하고 재구성 되거나, 클러스터에 오류가 생겨도 재구성되기까지 기다려야 한다는 단점이 있었다. 따라서 본 논문에서는 지역적인 재클러스터링을 통하여 네트워크를 최적으로 유지하며 클러스터들의 부하를 고려하여 망을 동적으로 재구성 하는 방법을 제안하였다. NS-2를 이용한 시뮬레이션을 통하여 기존의 방법에 비하여 본 논문에서 제안한 알고리즘이 네트워크 유지시간을 연장시켜 더 많은 양의 데이터가 수집됨을 확인 할 수 있었다.

• Journal of Korea Multimedia Society
• /
• v.7 no.10
• /
• pp.1400-1411
• /
• 2004

Recently, explosion of internet user requires fundamental changes on the architecture of Web service system, from single server system to clustered server system, in parallel with the effort for improving the scalability of the single internet server system. But current cluster-based server systems are dedicated to the single application, for example, One-IP server system. One-IP server system has a clustered computing node with the same function and tries to distribute each request based on the If to the clustered node evenly. In this paper, we implemented the more useful application service platform. It works on shared clustered server(back-end server) with an application server(front-end server) for a particular service. An application server provides a particular service at a low load by itself, but as the load increases, it reconfigures itself with one or more available server from the shared cluster and distributes the load on selected server evenly We used PVM for an effective management of the clustered server. We found the implemented application service platform provides more stable and scalable operation characteristics and has remarkable performance improvement on the dynamic load changes.