• 한국수소및신에너지학회논문집
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• 제29권3호
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• pp.251-259
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• 2018

Metal hydride based hydrogen storage under moderate temperature and pressure gives the safety advantage over the gas and liquid storage methods. Still solid-state hydrogen storage including metal hydride is below the DOE target level for automotive applications, but it can be adapted to stationary or miliary application reasonably. In order to develop a modular solid state hydrogen storage system that can be applied to a distributed power supply system composed of renewable energy - water electrolysis - fuel cell, the heat transfer and hydrogen storage characteristics of the metal hydride necessary for the module system design were investigated using AB5 type metal hydride, LCN2 ($La_{0.9}Ce_{0.1}Ni_5$). The planetary high energy mill (PHEM) treatment of LCN2 confirmed the initial hydrogen storage activation and hydrogen storage capacity through surface modification of LCN2 material. Expanded natural graphite (ENG) addition to LCN2, and compression molding at 500 atm improved the thermal conductivity of the solid hydrogen storage material.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제21권7호
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• pp.470-475
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• 2015

오픈스택은 개발자가 IaaS(Infrastructure as a Service) 클라우드 플랫폼을 구축할 수 있게 하는 오픈소스 소프트웨어이다. 오픈스택은 서버, 네트워크, 스토리지 자원들을 가상화하고, 사용자들에게 이를 제공한다. 본 논문에서는 입출력 연산 시 서버와 스토리지 노드 간에 발생할 수 있는 병목현상을 해결하기 위해 고속 통신을 지원하는 인피니밴드 스토리지 네트워크를 적용한 오픈스택 클라우드 스토리지 시스템의 구조를 제안한다. 또한 모든 SSD들에 분산 RAID-60 구조를 적용하여 Nova의 가상머신에서 사용 가능한 All Flash Array 기반의 고성능 Cinder 스토리지 볼륨을 구현하며, 오픈스택에 적용한 인피니밴드 스토리지 네트워크가 고성능 스토리지 가상화에 적합함을 보인다.

• 전기학회논문지P
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• 제65권2호
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• pp.94-100
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• 2016

A virtual power plant (VPP) technology is a cluster of distributed generation installations. VPP system is that integrates several types of distributed generation sources, so as to give a reliable overall power supply. Virtual power plant systems play a key role in the smart grids concept and the move towards alternative sources of energy. They ensure improved integration of the renewable energy generation into the grids and the electricity market. VPPs not only deal with the supply side, but also help manage demand and ensure reliability of grid functions through demand response (DR) and other load shifting approaches in real time. In this paper, utilizing a variety of distributed generation resources(such as emergency generator, commercial generator, energy storage device), activation scheme of the virtual power plant technology. In addition, through the analysis of the domestic electricity market, it describes a scheme that can be a virtual power plant to participate in electricity market. It attempts to derive the policy support recommendation in order to obtain the basics to the prepared in position of power generation companies for the commercialization of virtual power plant.

• International Journal of Contents
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• 제10권1호
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• pp.62-67
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• 2014

Usually, cloud storage systems are developed based on DFS (Distributed File System) for scalability and reliability reasons. DFSs are designed to improve throughput than IO response time, and therefore, they are appropriate for batch processing jobs. Recently, cloud storage systems have been used for update intensive applications such as OLTP and so on. However, in DFSs, in-place update operations are not carefully considered. Therefore, when updates are frequent, I/O performance of DFSs are degraded significantly. DFSs with RAID techniques have been proposed to improve their performance and reliability. Their performance degradation caused by frequent update operations can be more significant. In this paper, we propose an in-place update method for DFS RAID exploiting a differential logging technique. The proposed method reduces the I/O costs, network traffic and XOR operation costs for RAID. We demonstrate the efficiency of our proposed in-place update method through various experiments.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 춘계학술대회
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• pp.643-645
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• 2015

스토리지의 발달로 자동차 항공분야 등 실생활 어디에서든 스토리지가 활발히 활용되고 있다. 최근 빅데이터가 대두됨에 따라 많은 데이터를 스토리지에 저장하고 데이터를 처리하는 데이터 분산처리 연구가 활발히 진행되고 있다. 하지만 많은 사람들이 데이터를 동시에 요청할 때 병목현상이나 처리 속도가 느려지는 문제가 발생한다. 본 논문에서는 많은 데이터를 저장하고 처리해야하는 빅 데이터 분야에 사용될 것을 고려하여, 데이터 요청 시 보다 효율적으로 데이터를 처리하고 많은 데이터를 효율적인 관리가 가능한 데이터 경량화 처리 시스템 알고리즘을 제안한다.

• Fisheries and Aquatic Sciences
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• 제13권3호
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• pp.231-235
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• 2010

The effects of various natural antioxidant sources on oxidation of olive flounder (Paralichthys olivaceus) and fish diet during storage was determined. Juvenile fish were distributed among 18 flow-through tanks (40 fish per tank). Six experimental diets were prepared in triplicate: control (CT), antitox (AT), green tea extract (GE), fig extract (FE), Haeroc product (HP) and by-product of green tea (BG). The experimental diets were stored at two temperatures: room temperature ($26.8^{\circ}C$) for 14 days and frozen ($-30^{\circ}C$) for 16 weeks. Thirty fish were sampled from each tank at the end of the 8-week feeding trial. Whole bodies of fish were homogenized and stored in a home freezer ($-9.6^{\circ}C$) for 24 weeks. Acid values (AVs) and peroxide values (POVs) of the diets and frozen fish during storage were monitored. AVs of the experimental diets tended to increase with the storage period except for that of the HP diet at room temperature. POVs from FE, CT, and BG diets peaked at day 7 and then decreased through the remainder of the experiment. AVs of the experimental diets and fish increased with time at $-30^{\circ}C$ and $-9.6^{\circ}C$. Results of this study show that by-products of green tea and Haeroc product seem to have potential as antioxidants in fish feed to inhibit oxidation of both the feed and fish during storage.

• 한국멀티미디어학회논문지
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• 제15권12호
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• pp.1499-1505
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• 2012

Recently, the distributed processing system for big data has been actively investigated owing to the development of high speed network and storage technologies. In addition, virtual system that can provide efficient use of system resources through the consolidation of servers has been increasingly recognized. But, when we configure distributed processing system for big data in virtual machine environments, many problems occur. In this paper, we did an experiment on the optimization of I/O bandwidth according to the creation and placement of VMs and tasks with composing Hadoop cluster in virtual environments and evaluated the results of an experiment. These results conducted by this paper will be used in the study on the development of Hadoop Scheduler supporting I/O bandwidth balancing in virtual environments.

• 산업경영시스템학회지
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• 제19권40호
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• pp.169-178
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• 1996

Geographically dispersed computing system is made of computers interconnected by a telecommunications network. To make the system operated efficiently, system designer must determine the allocation of data files to each node. In designing such distributed computing system, the most important issue is the determination of the numbers and the locations where database files are allocated. This is commonly referred to as the file allocation problem (FAP)[3]. The proposed model is a 0/l integer programming problem minimizing the sum of file storage costs and communication(query and update) costs. File allocation problem belongs to the class of NP-Complete problems. Because of the complexity, it is hard to solve. So, this paper presents an efficient heuristic algorithm to solve the file allocation problem using Tabu Search Technique. By comparing the optimal solutions with the heuristic solutions, it is believed that the proposed heuristic algorithm gives good solutions. Through the experimentation of various starting points and tabu restrictions, this paper presents fast and efficient method to solve the file allocation problem in the distributed computing system.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2006년도 가을 학술발표논문집 Vol.33 No.2 (C)
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• pp.235-239
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• 2006

최근 컴퓨팅 환경은 인터넷 환경의 웹을 기반으로 한 분산 컴퓨팅 환경으로 변화하고 있다. 그에 따라 XML 문서의 사용과 XML 문서의 양이 급속하게 증가하였으며, 언제라도 쉽게 필요한 XML 문서에 접근할 수 있어야 한다. XML 문서에서 정보를 검색하기 위하여 XPath 질의어가 널리 사용 중이며, XML 저장 기법과 XPath를 이용한 질의 처리에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 분산 객체 관계 데이터베이스 시스템을 이용하여 XML 문서를 저장하고 관리하는 시스템을 설계하였으며 분산된 XML 데이터를 접근할 수 있도록 하기 위해 XPath를 분산 SQL로 변환하여 실행하는 분산 XPath 질의 처리기를 설계 및 구현하였다.

• 전기학회논문지P
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• 제58권2호
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• pp.116-121
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• 2009

Distributed power systems (DPSs) has been widely used various industrial/military applications due to their various advantages. Furthermore, the "All electric" concept, in conjunction with DC DPS, appears to be more advanced and mature in the AEV(All-Electric Vehicular) industry. Generally, AEV carry many loads with varied functions. However, there may be large pulsed loads with short duty ratios which can affect the normal operation of other loads. In this paper, a converter with spilt capacitors and a simple adaptive controller is proposed as a active damping device to mitigate the voltage transients on the bus. The proposed converter allows the smaller capacitive storage. In addition, the proposed control approach has the advantage of requiring only one sensor and performing both the functions of mitigating the voltage bus transients and maintaining the level of energy stored. The control algorithm has been implemented on a TMS320F2812 Digital Signal Processor (DSP). Simulation and experimental results are presented which verify the proposed control principle and demonstrate the practicality of the circuit topology.