• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.906-908
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• 2010

클라우드 컴퓨팅 환경을 구축할 수 있게 하는 OpenNebula는 ONE 스케줄러를 통해 가상머신들의 라이프 사이클을 관리한다. ONE 스케줄러는 가상머신을 할당 할 때, 클러스터 노드의 물리적 자원 할당 여부만을 고려하기 때문에 가상 머신 생성 후의 부하를 예측하기 힘들다. 본 논문에서는 사용자의 이전 가상 머신 사용 패턴을 기반으로 부하 등급을 나누고 이 등급에 따라 가상머신을 동적으로 할당하는 기법을 제안한다.

• KIISE Transactions on Computing Practices
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• v.23 no.1
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• pp.45-56
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• 2017

In astronomy, the amount of data generated using wide-field optical telescope has increased exponentially. However, the fixed-size small-scale computing environment and the complexity of data analysis tools, results in difficulties to process the massive observation data collected. To resolve this problem, we propose a cloud-based automation system for the efficient processing of the enormous data gathered. The proposed system consists of a Workflow Execution Manager which manages various workflow templates and controls the execution of workflows instantiated from theses templates, and an Elastic Resource Manager that dynamically adds/deletes computing resources, according to the amount of data analysis requests. To show the effectiveness of our proposed system, we exhaustively explored a board spectrum of experiments, like elastic resources allocation, system load, etc. Finally, we describe the best practice case of DEEP-SOUTH scheduling system as an example application.

• Proceedings of the Korea Information Assurance Society Conference
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• 2004.05a
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• pp.111-117
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• 2004

In distributed-computing environments, there is a strong demand for the authentication and the access control of distributed-shared resources. I have presented role-based access control (RBAC) concept that is in the spotlight recently. RBAC model shows the standardized access control of complicated organization's resources. In RBAC, senior role has junior role's permission by virtue of role hierarchy. But, junior role cannot perform the permission, which is granted to the senior or other role groups. Inheritances of permissions in role hierarchies are static. In order to tackle this problem, I propose a dynamic role assignment, which classified into passive role assignment and active role assignment, and design dynamic role assignment protocol and implement role assignment server.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.1B
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• pp.11-17
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• 2003

In this paper, we presented the dynamic random access channel allocation method under the priority based scheduling policy in order to improve the system performance of HIPERLAN/2 standardized by ETSI According to the scheduling policy, AP scheduler primarily allocates the resource to the collision MT This scheduling policy bring about decreasing the transmission delay of collision MT Dynamic RCH(random access channel) allocation method decreases the collision probability by increasing the number of RCH slots in case of low traffic. While it increases the maximum throughput by increasing the number of the data transmission slots in case of high traffic Therefore dynamic allocation method of RCH slots decreases the scheduling delay and increases the throughput When we evaluate the performance of presented method based on standards, we saw that the presented method improve the performance of the MAC protocol in terms of throughput and transmission delay.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1450-1458
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• 2011

The HPcN (Hybrid & high Performance Convergence Network) in research networks means environment which can provide both computing resource such as supercomputer, cluster and network resource to application researchers in the field of medical, bio, aerospace and e-science. The most representative research network in Korea, KREONET has been developing following technologies through the HERO (Hybrid Networking project for research oriented infrastructure) from 200S. First, we have constructed and deployed a control plane technology which can provide a connection oriented network dynamically. Second, the integrated resource management system technology has been developing for reservation and allocation of both computing and network resources, whenever users want to utilize them. In this paper, a testbed network is presented, which is possible to reserve and allocate network resource using the integrated resource management system. We reserve network resource through GNSI (Grid Network Service Interface) messages between GRS (Global Resource Scheduler) and NRM (Network Resource Manager) and allocate network resource through GUNI (Grid User Network Interface) messages between the NRM (network resource manager) and routers, based on reservation information provided from a user on the web portal. It is confirmed that GUNI interface messages are delivered from the NRM to each router at the starting of reservation time and traffic is transmitted through LSP allocated by the NRM.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05b
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• pp.1137-1140
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• 2003

네트워크의 QoS를 지원하기 위해서는 자원 관리에 적응제어구조의 도입이 필요하다. 이를 위해서는 사전에 네트워크의 대역폭 할당에 따른 전송률 응답특성을 구현하는 모델의 개발이 필수적이며 이 모델을 통하여 적응제어구조의 최적화를 진행해야 한다. 본 연구에서는 두 가지 방식의 모델을 제안하였다. 첫째는 동적 시스템 모델이며 다른 하나는 통계적 모델이다. 동적 시스템 모델은 네트워크의 동적 특성을 고려하여 도입하였으며, 통계적 모델은 측정된 전송률 데이터의 분포를 고려하여 도입하였다. 제시된 두 모델의 인자 결정을 위해 최적화 기법을 사용하였으며, 결과적으로 제시된 두 모델이 실제 네트워크의 동작과 유사함을 살펴보았다.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.425-428
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• 2009

본 논문에서는 유럽의 표준화 기구인 ETSI(European Telecommunication Standards Institute)에서 제정한 HiperLAN/2 MAC계층에서 각 단말들의 매체 접근 경쟁방식을 분석하고 아울러 효율적인 자원분배가 이루어지도록 RCH 채널을 할당하는 방법을 분석한다. HiperLAN/2에서는 RCH를 통해서 자원 요청을 받게 되는데 만약 트래픽부하가 큰 경우 RCH가 적게 할당되면 전송지연이 길어질 것이며 반대로 RCH가 필요이상으로 할당되면 수율이 저하되는 문제가 발생한다. 본 논문에서는 이전 프레임에서 성공한 RCH 채널과 충돌한 RCH 채널의 각 크기를 비교하여 현재 프레임의 RCH 채널수를 결정하는 방식을 제안한다. 제안한 방식의 효율성을 입증하기 위해 시뮬레이션을 수행하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2769-2774
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• 2013

The key of USN(Ubiquitous Sensor Network) technology is low power wireless communication technology and proper resource allocation technology for efficient routing. The distinguished resource allocation method is needed for efficient routing in sensor network. To solve this problems, we propose an algorithm that can be adopted in USN with making up for weak points of PQ and WRR in this paper. The proposed algorithm produces the control discipline by the fuzzy theory to dynamically assign the weight of WRR scheduler with checking the Queue status of each class in sensor network. From simulation results, the proposed algorithm improves the packet loss rate of the EF class traffic to 6.5% by comparison with WRR scheduling method and that of the AF4 class traffic to 45% by comparison with PQ scheduling method.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.10
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• pp.8-15
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• 2003

In this paper, we address how to provide absolute differentiated services for optical burst switching (OBS) networks based on dynamic wavelength assignment. Unlike existing quality of service (QoS), such as buffer-based and offset-time based scheme, our proposed dynamicvirtual lambda partitioning (DVLP) scheme does not mandate any buffer or extra offset time, but can achieve absolute service differentiation between classes. This new DVLP scheme shares wavelength resources based on several different priority of classes in an efficient and QoS guaranteed manner. The performance results show that the proposed scheme effectively guarantees a target blocking probability of each traffic classes both in Poisson and Self-similar traffic environment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.10
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• pp.1210-1220
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• 2016

As modern warfare has changed into network centered, the ability to share situational awareness among allies become a core competency for performing operational missions. In an airborne environment, it uses a tactical data link such as Link-16 for shared situational awareness. There exist problems when it shares situational awareness over the existing data link that can not allocate slots dynamically or that can not change the number of a slot to be allocated. In addition, there was a problem that can not share this failure so that failed to improves situation awareness because of finite time slot resources. In this paper, we accommodate dynamic slot allocation and changes of slot allocation with mixed structure of TDMA (time division multiple access) and random access. We propose a technique that can be used when available slots are exhausted, and a load balancing method to prevent slot allocation delay when slot requesting or message sending is concentrated on a single subframe.