• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.118-120
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• 2013

클라우드 컴퓨팅에서 IaaS(Infrastructure-as-a-service)는 서버, 스토리지, 네트워크 등을 가상화 환경으로 만들어 활용할 수 있도록 하는 서비스이다. 이러한 서비스를 통해 기업들은 초기 인프라 비용을 절약하는 등의 장점을 얻을 수 있기 때문에 많은 관심을 가지고 사용하고 있다. 이러한 사용자들의 증가로 물리적인 자원을 바로 증가시키는 대신 가상머신을 통한 자원의 할당을 좀 더 효율적으로 하는 것에 중점을 두게 되었다. 본 논문에서는 기본적으로 사용되는 자원 할당 기법들과 발전되어 제안된 기법 등 5가지 스케줄링 기법을 비교 및 분석한다. 여러 상황에서 각각의 기법은 장점과 단점을 가진다. 분석 결과를 바탕으로, IaaS를 제공하는 기업에서는 사용자들의 편의와 자신들의 상황에 맞는 자원 할당 스케줄링 기법을 선택할 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.1383-1386
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• 2008

분산된 자원의 실시간 정보교환과 그리드를 통한 효율적인 자원 재구성을 위해서는 기존의 단일 도메인에서 구성되는 네트워크와는 다르게 대규모 가상도메인(Large-Scale Multi-domain)을 위한 네트워크의 성능과 기능 향상이 필요하다. 그리드네트워크를 기반으로 활발히 진행 중인 글로벌한 연구자원을 대상으로 공유된 자원의 성능 개선과 자원 간 데이터전달의 효율 개선을 위해 TDM(Time Division Multiplexing)기반의 Multi-Point Lambda-Path Ring 구현 기술을 제안하고 이를 Multi-Domain 간 Control Plane하에서 최적의 가상도메인으로 구성 할 수 있는 기법을 제안한다.

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

• Journal of the Korea Convergence Society
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• v.5 no.4
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• pp.93-99
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• 2014

Cloud computing refers to borrow IT resources as needed by leveraging Internet technology and pay as much as you used by supporting real-time scalability depending on the service load. Virtualization which is the main technology of cloud computing is a technology that server, storage and hardware are regarded as not separate system but one system area and are allocated as needed. However, the security mechanisms provided by virtualized environments are difficult to cope with the traditional security mechanisms, having basic levels of visibility, control and audit function, on which the server is designed to monitor the traffic between the servers. In this paper, the security vulnerabilities of virtualization are analysed in the cloud computing environment and cloud virtualization security recommendations are proposed.

• Journal of the Korea Society of Computer and Information
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• v.18 no.7
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• pp.11-21
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• 2013

Recently operating a large scale computing resource like a data center becomes easier because of the virtualization technology that virtualize servers and enable flexible resource provision. The most of public cloud services provides automatic scaling in the form of scale-in or scale-out and these scaling approaches works well to satisfy the service level agreement (SLA) of users. However, a novel scaling approach is required to operate private clouds that has smaller amount of computing resources than vast resources of public clouds. In this paper, we propose a hybrid server scaling architecture and related algorithms using both scale-in and scale-out to achieve higher resource utilization rate for private clouds. We uses dynamic resource allocation and live migration to run our proposed algorithm. Our propose system aims to provide a fine-grain resource scaling by steps. Thus private cloud systems are able to keep stable service and to reduce server management cost by optimizing server utilization. The experiment results show that our proposed approach performs better in resource utilization than the scale-out approach based on the number of users.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.32-35
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• 2017

직접 통로(Direct Pass-through) 기반 GPU(Graphic Processing Unit) 가상화 기법은 클라우드 환경에서 가상머신에게 GPU 장치의 기능을 지원하기 위한 일반적인 방법 중 하나이다. GPU 장치는 GPGPU 기술을 통해 연산을 가속화 할 수 있기 때문에 클라우드 환경에서도 가상머신에 고성능 연산을 지원하기 위해 많이 사용되고 있다. 하지만 기존 가상머신 스케줄링 기법은 가상머신의 CPU 사용 시간을 기반으로 스케줄링 되며, GPU 자원 사용을 고려하지 않는다. 본 논문에서는 GPU와 CPU 연산을 수행하는 가상머신들이 동시에 실행되는 환경에서 성능 실험을 통해 가상머신의 GPU 연산이 다른 가상머신에게 미치는 성능 영향과 GPU 작업 길이가 다른 가상머신에게 미치는 영향을 분석한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.457-460
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• 2014

클라우드 컴퓨팅은 IT 자원의 효율적인 관리와 비용 대비 양질의 서비스 제공을 위한 새로운 패러다임으로써, 국내외의 기업뿐만 아니라 많은 사용자들에게 주목 받고 있다. 하지만 관련 시장의 빠른 성장과 함께 다양한 사이버 범죄에 노출될 수 있는 위험이 높아졌음에도 불구하고, 클라우드 컴퓨팅에 대한 디지털 포렌식은 실질적인 역할을 수행하기에 아직 미비한 실정이다. 클라우드 컴퓨팅은 증거 데이터가 물리적으로 분산되어 있고, 자원이 가상공간에 존재할 수 있기 때문에 기존의 디지털 포렌식 수사와는 다르게 접근해야 한다. 이에, 본 논문에서는 추상화된 클라우드 계층에 따른 기존 포렌식 절차 상의 데이터 수집 방법에 관한 한계를 분석하고, 확보한 증거 데이터의 신뢰성 보장 및 다양한 클라우드 환경에 보다 유연하게 적용할 수 있는 디지털 증거 수집 절차를 제안한다. 해당 절차는 클라우드 구성 요소들 중 물리적인 자원들을 가상화하여 논리적으로 구성할 수 있도록 하며, 가상화된 자원들을 서비스 목적에 따라 폭넓게 활용할 수 있도록 관리 체계를 제공해주는 클라우드 플랫폼을 기반으로 한다.

• Journal of Convergence for Information Technology
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• v.8 no.5
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• pp.69-75
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• 2018

The purpose of access control is to prevent computing resources from illegal behavior such as leakage, modification, and destruction by unauthorized users. As the cloud computing environment is expanded to resource sharing services using virtualization technology, a new security model and access control technique are required to provide dynamic and secure cloud-based computing services. The virtualization management convergence access control model provides a flexible user authorization function by applying the dynamic privilege assignment function to the role based access control mechanism. In addition, by applying access control mechanism based on security level and rules, we solve the conflict problem in virtual machine system and guarantee the safeness of physical resources. This model will help to build a secure and efficient cloud-based virtualization management system and will be expanded to a mechanism that reflects the multi-level characteristics.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.3
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• pp.567-575
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• 2011

The two most popular virtual machine allocation schemes, both match making and round robin, do consider hardware specifications such as CPU, RAM, and HDD, but not CPU usage, which results in balanced resource distribution, but not in balanced resource usage. Thus, in this paper a new virtual machine allocation scheme considering current CPU usage rate is proposed while retaining even distribution of node resources. In order to evaluate the performance of the proposed scheme, a cloud computing platform composed of three cloud nodes and one front end is implemented. The proposed allocation scheme was compared with both match making and round robin schemes. Experimental results show that the proposed scheme performs better in even distribution of overall CPU usage, which results in efficient load balancing.

• Journal of Digital Contents Society
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• v.15 no.5
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• pp.595-602
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• 2014

Cloud computing is already well known paradigm that a support computing resource flexible and scalable to users as the want in distributed computing environment. Actually, cloud computing can be implemented and provided by virtualization technology. Also, various products are released or under development. In this paper, we built the teaching practice system using cloud computing and evaluated practical environment which constructed over a virtual machine. Virtualization-based cloud computing provides optimized computing resources, as well as easy to manage practical resource and result. Therefore, we can save the time for configuration of practice environment. In the view of faculty, they can easily handle the practice result. Also, those practice condition reuse comfortably and apply to various configuration simply. And then we can increase capabilities and availabilities of limited resources. Additionally, we measure the performance requirements for educational applications through evaluation of virtual-based teaching practical system in advance.