• KIISE Transactions on Computing Practices
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• v.20 no.12
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• pp.658-663
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• 2014

Due to the rapid development of open source based Cloud management platforms such as OpenStack, many and various individuals and institutions are trying to construct Cloud computing systems based on open source software projects. It is essential, for those who install, administrate or operate a Cloud, to validate the integrity of the constructed Cloud system. This paper, therefore, proposes the design of a testing tool for validating the integrity of a constructed OpenStack-based Cloud system. Especially, the proposed testing tool utilizes the Tempest project which is an open source project that consists of OpenStack test cases. The proposed testing tool is expected to help developing Cloud technology and Cloud users.

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.1
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• pp.60-65
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• 2017

Network virtualization enables us to make efficient use of resources in a physical network by embedding multiple virtual networks in the physical network. In this paper, we develop a prototype of a virtual network embedding system. Our system consists of OpenStack, which is an open source cloud service platform, and shell scripts. Because OpenStack does not provide a quality of service control function, we realize bandwidth reservation for virtual links by making use of the ingress policing function of Open vSwitch, which is a virtual switch used in OpenStack. The shell scripts in our system automatically construct the required virtual network on the physical network using the OpenStack command-line interface, and they reserve bandwidth for virtual links using the Open vSwitch command. Experimental evaluation confirms that our system constructs the requested virtual network and appropriately allocates node and link resources to it.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.4
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• pp.141-152
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• 2013

The applications and concerned technologies of cloud computing services, one of major trends in the information communication technology, are widely progressing and advancing. OpenStack, one of open source cloud computing platforms, is comprised of several service components; using these, it can be possible to build public or private cloud computing service for a given target application. In this study, a remote sensing image analysis processing service on cloud computing environment has designed and implemented as an operational test application in the private cloud computing environment based on OpenStack. The implemented service is divided into instance server, web service, and mobile app. A instance server provides remote sensing image processing and database functions, and the web service works for storage and management of remote sensing image from user sides. The mobile app provides functions for remote sensing images visualization and some requests.

• Korean Journal of Remote Sensing
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• v.33 no.4
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• pp.339-350
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• 2017

In recent, cloud computing paradigm and open source as a huge trend in the Information Communication Technology (ICT) are widely applied, being closely interrelated to each other in the various applications. The integrated services by both technologies is generally regarded as one of a prospective web-based business models impacting the concerned industries. In spite of progressing those technologies, there are a few application cases in the geo-based application domains. The purpose of this study is to develop a cloud-based service system for satellite image processing based on the pure and full open source. On the OpenStack, cloud computing open source, virtual servers for system management by open source stack and image processing functionalities provided by OTB have been built or constructed. In this stage, practical image processing functions for KOMPSAT within this service system are thresholding segmentation, pan-sharpening with multi-resolution image sets, change detection with paired image sets. This is the first case in which a government-supporting space science institution provides cloud-based services for satellite image processing functionalities based on pure open source stack. It is expected that this implemented system can expand with further image processing algorithms using public and open data sets.

• Electronics and Telecommunications Trends
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• v.29 no.5
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• pp.136-144
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• 2014

오늘날 ICT(Information & Communication Technology)분야의 최대 화두를 꼽는다면 빅데이터, IoT(Internet of Things), 그리고 클라우드를 빼놓을 수 없다. 아직 국내에서는 클라우드 관련 산업 및 시장이 본격적으로 활성화되고 있지는 못하지만, 다양한 규모와 형태의 클라우드 인프라를 손쉽게 구축하고 관리할 수 있는 클라우드 운영체제의 출현과 기술 고도화로 기업의 ICT 환경을 클라우드로 전환하는 사설 클라우드의 구축이나 공용 클라우드와 사설 클라우드를 적절히 함께 운용하는 하이브리드 클라우드에 대한 관심이 매우 높은 실정이다. 현재 이러한 흐름을 이끌며 가장 많은 주목을 받고 있는 것이 바로 공개 소프트웨어 기반의 클라우드 운영체제인 OpenStack이다. 본고에서는 OpenStack의 최근 배포판인 Icehouse를 중심으로 OpenStack의 구성과 주요 특징 그리고 기술동향을 정리한다.

• Electronics and Telecommunications Trends
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• v.30 no.2
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• pp.95-103
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• 2015

오픈스택(OpenStack)을 이용한 클라우드 서비스가 점차 확산되어가면서 수많은 가상 자원들을 생성하고 생성된 가상 자원들의 라이프사이클을 관리하는 오케스트레이션 기능의 중요성이 강조되고 있다. 본고에서는 오픈스택 진영에서 템플릿 기반의 오케스트레이션 서비스를 담당하고 있는 Heat의 기본구조와 함께 Heat에서 정의하고 있는 HOT(Heat Orchestration Template) 템플릿의 구성 요소와 주요 특징을 정리하고 템플릿 간에 참조 관계를 설명하는 Nested Stack 개념을 소개한다.

• Journal of the Korea Society of Computer and Information
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• v.21 no.1
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• pp.65-72
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• 2016

Network virtualization is an emerging technology for solving the rigidity of the physical network infrastructure. The innovative technique virtualizes all resources in the network, including the network links and nodes, and provides a number of virtual networks on a single network infrastructure. In order to realize a virtual network, a thorough and complete monitoring of all resources in the network should be performed firstly. OpenFlow is an open source stack for network virtualization. However, it is impossible to apply OpenFlow to AP-based legacy wireless LAN environment because OpenFlow targets ethernet-based LAN environment. In this paper, we implement an adaptor-styled virtual switch for AP-based wireless LAN through customizing the Open vSwitch which is a virtual switch of OpenFlow. The evaluation test results show that the implemented OpenFlow stack operates successfully. The implemented OpenFlow stack can now be plugged immediately in existing AP-based wireless LAN environment and plays network resource monitoring. In the future, we can develop wireless LAN virtualization applications on the wireless OpenFlow stack.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.12-19
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• 2022

Cathode open-type PEMFC (Proton Exchange Membrane Fuel Cells) stacks, which are widely used in small transport-type PEMFC, have a problem with poor durability. Through the accelerated durability test of the 13-cell PEMFC stack, we tried to find the cause of the degradation of the stack and to contribute to the improvement of the durability of the cathode open stack. A hydrogen/air boundary is formed during start-up/shut-down (SU/SD) due to the structural problem of the cathode open stack in which the cathode is open to the atmosphere and it is difficult to maintain airtightness, thereby deteriorating the cathode. In this study, it was possible to evaluate the durability in a relatively short time by reducing the 54% of the initial performance by repeating SU/SD 1,800 times on the cathode open stack. After dismantling the stack, each cell was divided into two and the performance was analyzed. Overall, the anode outlet MEA, which facilitates air inflow, showed more severe electrode deterioration than the inlet MEA, confirming that the hydrogen/air boundary formation during SU/SD is the main cause of degradation.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.134-138
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• 2004

The discrepancies between theoretical values and measured data of PEFC(Proton Exchange Fuel Cell) is carried out for the machine tool power generation. Rudimental approach of theoretical fuel cell open circuit potential using Gibbs free energy is employed for the examination of PEFC module. The stack temperature, stack voltage and stack current are measured during the operation of PEFC module. It is found that stack voltage and current values show the pronounced discrepancy with the results calculated by Gibbs free energy approach. It is analysed that the discrepancy is due to activation polarization, concentration overvoltage and ohmic overvoltage.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.11
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• pp.5404-5424
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• 2018

This work is mainly focused on two major topics in cloud platforms by using OpenStack as a case study: management and provisioning of resources to meet the requirements of a service demanded by remote end-user and relocation of virtual machines (VMs) requests to offload the encumbered compute nodes. The general framework architecture contains two subsystems: 1) An orchestrator that allows to systematize provisioning and resource management in OpenStack, and 2) A resource utilization based subsystem for vibrant VM relocation in OpenStack. The suggested orchestrator provisions and manages resources by: 1) manipulating application program interfaces (APIs) delivered by the cloud supplier in order to allocate/control/manage storage and compute resources; 2) interrelating with software-defined networking (SDN) controller to acquire the details of the accessible resources, and training the variations/rules to manage the network based on the requirements of cloud service. For resource provisioning, an algorithm is suggested, which provisions resources on the basis of unused resources in a pool of VMs. A sub-system is suggested for VM relocation in a cloud computing platform. The framework decides the proposed overload recognition, VM allocation algorithms for VM relocation in clouds and VM selection.