• Proceedings of the Korea Information Processing Society Conference
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• 2002.11a
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• pp.171-174
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• 2002

네트워크의 발달로 그리드 환경의 구현이 가능하게 되었다. 이기종간의 리소스들을 연결하여 초고속 고성능의 환경을 제공하는 그리드 환경을 사용하기 위해 보다 쉽고 투명성 있는 사용자 환경이 요구되고 있다. 이에 따라 PSE(Problem Solving Environment)가 그리드 사용자 환경으로 대두되고 있다. 이 논문에서는 PSE 의 연구 동향을 조사 분석하고, 국내 그리드 환경을 위한 PSE 를 정립하고자 한다. 접근방법은 PSE 가 제공해야 할 환경들을 정의하고 구현에 필요한 PSE 시스템을 설계 제시 하고자 한다.

• Journal of Communications and Networks
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• v.14 no.6
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• pp.619-628
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• 2012

The ZigBee network has been considered to monitor electricity usage of home appliances in the smart grid network. ZigBee, however, may suffer from a coexistence problem with wireless local area network (WLAN). In this paper, to resolve the coexistence problem between ZigBee network and WLAN, we propose a new protocol constructing a cognitive smart grid network for supporting monitoring of home appliances. In the proposed protocol, home appliances first estimates the transmission timing and channel information of WLAN by reading request to send/clear to send (RTS/CTS) frames of WLAN. Next, based on the estimated information, home appliances transmit a data at the same time as WLAN transmission. To manage the interference between WLAN and smart grid network, we propose a cognitive beamforming algorithm. The beamforming algorithm is designed to guaranteeing zero interference to WLAN while satisfying a required rate for smart metering. We also propose an energy efficient rate adaptation algorithm. By slowing down the transmission rate while satisfying an imperceptible impact of quality of service (QoS) of the receiver, the home appliance can significantly save transmit power. Numerical results show that the proposed multiple antenna technique provides reliable communications for smart metering with reduced power comparing to the simple transmission technique.

• Journal of Electrical Engineering and Technology
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• v.9 no.4
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• pp.1240-1247
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• 2014

The applications of Distributed Generation (DG) in a smart distribution grid environment are widely employed especially for power balancing and supporting demand responses. Using these applications can have both positive and negative impacts on the distribution system. The sizing and location of their installations are the issues that should be taken into consideration to gain the maximum benefit from them when considering the economic aspects. This paper presents an application of the Bat Algorithm (BA) for the optimal sizing and siting of DG in a smart distribution power system in order to maximize the Benefit to Cost Ratio (BCR), subjected to system constraints including real and reactive power generation, line and transformer loading, voltage profile, energy losses, fault level as well as DG operating limits. To demonstrate the effectiveness of the proposed methodology and the impact of considering economic issues on DG placement, a simplify 9-bus radial distribution system of the Provincial Electricity Authority of Thailand (PEA) is selected for the computer simulation to explore the benefit of the optimal DG placement and the performance of the proposed approach.

• Journal of Agricultural Extension & Community Development
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• v.28 no.1
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• pp.53-68
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• 2021

This study aimis to identify policy priorities for promoting youth activities through the Importance-Performance Analysis (IPA). IPA is used to identify policy priorities for promoting local youth activities. The IPA tabulated result is presented in a two-dimensional grid to showing for promoting local youth activities, The require concentrate support part is divided into 3 parts. Problem solve supporting at work development of leisure activities programs, leisure activities programs developing and development of leisure-related professionals. And leisure-related professionals developing. The next parts that require continuous management were divided into four parts. The next parts that require continuous management is divided into four parts. Creating rental housing for young people, support for housing expenses supporting, loans supporting, and Holiday guaranteed. Based on the factors that support youth activities that make up the IPA matrix, the implications of revitalizing local youth activities is presented as below. First, ensuring employment of local youth and efforts to create sustainable jobs. Second, continuous efforts to improve the housing conditions of local youth, and third, policy support is needed for local youth to do various leisure activities.

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

• 한국전산유체공학회:학술대회논문집
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• 2001.10a
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• pp.182-189
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• 2001

A project has been initiated at KISTI Supercomputing Center at year 1999 to build a Tflops cluster in order to support newly emerging demands for larger scale parallel computing resources. As a supportive substitute of traditional supercompters, the cluster systems are expected to play important role in supporting diversified computational needs. In this paper, KISTI Supercomputing Center's working status of building Tflops cluster system and future plans.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06a
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• pp.40-41
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• 2010

• Tribology and Lubricants
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• v.22 no.3
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• pp.144-148
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• 2006

The experimental investigation was performed to find the associated changes in characteristics of fretting wear with various water temperatures. The fretting wear tests were carried out using the zirconium alloy tubes and the grids with increasing the water temperature. The tube materials in water of $20^{\circ}C,\;50^{\circ}C\;and\;80^{\circ}C$ were tested with the applied load of 20 N and the relative amplitude of $200{\mu}m$. The worn surfaces were observed by SEM, EDX analysis and 2D surface profiler. As the water temperature increased, the wear volume was decreased, but oxide layer was increased on the worn surface. The abrasive wear mechanism was observed at water temperature of $20^{\circ}C$ and adhesive wear mechanism occurred at water temperature of $50^{\circ}C,\;80^{\circ}C$. As the water temperature increased, surface micro-hardness was decreased, but wear depth and wear width were decreased due to increasing stick phenomenon. Stick regime occurred due to the formation of oxide layer on the worn surface with increasing water temperatures

• Spatial Information Research
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• v.18 no.3
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• pp.53-62
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• 2010

Recent development in wireless communication technology, like GPS, and mobile equipments, like PDA and cellular phone, make location-based services (LBSs) popular. However, because, users continuously request a query to a server in the LBSs by using their exact locations, privacy information could be in danger. Therefore, a mechanism for users' privacy protection is required for the safe and comfortable use of LBSs by mobile users. For this, we, in this paper, propose a grid-based cloaking area creation scheme supporting continuous LBSs in peer-to-peer environment. The proposed scheme creates a cloaking area by using Chord protocol, so as to support the continuous LBSs in peer-to-peer environment. Finally, we show from a performance analysis that our cloaking scheme outperforms the existing cloaking schemes, in terms of service time.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.6
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• pp.512-519
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• 2004

This paper described the free vibration characteristics of Optimized H Type (OHT) spacer grids (SG) supporting the PWR fuel rod. The vibration test and the finite element (FE) analysis are performed under the free boundary condition and the clamped at two points (or three points) in the bottom which is the same one as the experimental condition for the dummy rod continuously supported by spacer grids. A modal test is conducted by the impulse excitation method using an impulse hammer and an accelerometer, and the TDAS module of the I-DEAS software is used to acquire and analyze the sensor signals. The softwares related to the FE analysis are the I-DEAS for the geometrical shape modeling and meshing, and the ABAQUS for solving. The fundamental frequency of the OHT SG by experiment under a clamped condition at two points is 175.18 Hz, and shows a bending mode. We think there is no resonance between the fuel rod and the SG because the SG's frequency is higher than that of the fuel rod existing in the range from 30 to 120 Hz. The fundamental frequency of the SG under the free boundary condition is 349.2 Hz showing a bending mode, and the results between the test and the analysis have a good agreement with maximum 7 ％ in error It is also found that the FE analysis model of the OHT SGs to analyze an impact, a buckling and vibration et al. has been generated with reliability.