• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제6권2호
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• pp.130-139
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• 1994

A cycle analysis was performed for 2-stage expansion Claude refrigerators by a numerical method. The refrigerators are under recent development such that the reciprocating expanders of Collins cycle are replaced by new turboexpanders. A computer simulation program was written to predict the coefficient of performance of the refrigerators for several input parameters. It was found out that there exist unique optimum values for the ratio of expanded mass through the turboexpanders to the total mass and for the intermediate pressure of the 2-stage expansion. The maximum coefficient of performance was about $5{\times}10^{-4}$ at the optimal operation.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 한국전산구조공학회 1998년도 가을 학술발표회 논문집
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• pp.11-18
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• 1998

In this paper the stochastic analysis of semi-infinite domain is presented using the weighted integral method, which is expanded to include the infinite finite elements. The semi-infinite domain can be thought as to have more uncertainties than the ordinary finite domain in material constants, which shows the needs of and the importance of the stochastic finite element analysis. The Bettess's infinite element is adopted with the theoretical decomposition of the strain matrix to calculate the deviatoric stiffness of the semi-infinite domains. The calculated value of mean and the covariance of the displacement are revealed to be larger than those given by the finite domain assumptions giving the rational results which should be considered in the design of structures on semi-infinite domains.

• Journal of the Korean Chemical Society
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• 제38권2호
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• pp.87-91
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• 1994

The reparation and characterization of cellulose esters LB films with various alkyl chain lengths were studied. Monolayers of cellulose triesters with medium chain length such as trioctanoate(C-8), tridecanoate(C-10), and tridodecanoate(C-12), exhibited a characteristic phase transition from expanded to condensed states. The mechanism of phase transition was discussed on the basis of the temperature dependence of the surface $pressure-area(\pi-A)$ isotherms. By the horizontal dipping method, X-type multilayers of cellulose esters were prepared and characterized using the contact angle and XPS spectra.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 한국소성가공학회 2007년도 추계학술대회 논문집
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• pp.112-115
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• 2007

In order to investigate the residual stress evolution during the leveling process of hot rolled high strength coils for cold forming, the in-plane residual stress of plate sampled at SPM, rough leveler and finish leveler were measured by cutting method. Residual stress was localized near the edge of plate. As the thickness of plate was increased, the region with residual stress was expanded. The gradient of residual stress within plate was reduced during the leveling process. But the residual stress itself was not removed at the ranges of tested conditions. From the measured residual stress distribution within the plate, camber of plate cut to small width was predicted exactly within error range of experiment.

• Journal of the Korean Society of Combustion
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• 제20권4호
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• pp.42-48
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• 2015

This study was investigated the estimation of VOCs (Volatile Organic Compounds) emission from a gas station tank. To improve the atmosphere environmental quality near the gas station, the installation of vapor recovery system has been expanded recently. Therefore, it was necessary to calculate VOCs emissions from the gas station tank with vapor recovery systems for evaluation of their performance. The VOCs emissions are difficult to measure directly because of various sources and irregularly emission by pressure rise. In this study, VOCs emissions were estimated by simple calculation based on the equation of state for measured pressure, temperature and volume of a gasoline tank at a gas station. The result confirmed that the present national emission factor did not have significant discrepancy with the calculated value.

• International Journal of Contents
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• 제5권3호
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• pp.57-64
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• 2009

Korea has relied on top down development method, in which companies, research and education institutions move into the industrial complexes established by the government. However, to improve local competitiveness, the paradigm is shifting from the government initiated industrial complex to the clusters based on the cooperative network of the region. Representative case is 'Samcheok-si Fire & Emergency industry cluster construction project' that begun in 2007. AHP technique analysis results on first-stage showed that priority was on policy and network elements, and the results of second-stage analysis show that priority was on Policy incentives to internationalize the cluster and strengthen link,. Cluster branding, Sharing of organizational culture to cope with changes in environment, Creation of group learning culture. The subject of this research is limited to Samcheok-si's the Fire and Emergency Industry cluster formation project. Therefore, the research area and standard should be expanded to increase generality in further researches.

• Journal of the Korea Safety Management & Science
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• 제11권3호
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• pp.157-166
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• 2009

In this study, we developed a heuristic algorithm to get better efficiency of clustering than conventional algorithms. Conventional clustering algorithm had lower efficiency of clustering as there were no solid method for selecting initial center of cluster and as they had difficulty in search solution for clustering. EMC(Expanded Moving Center) heuristic algorithm was suggested to clear the problem of low efficiency in clustering. We developed algorithm to select initial center of cluster and search solution systematically in clustering. Experiments of clustering are performed to evaluate performance of EMC heuristic algorithm. Squared-error of EMC heuristic algorithm showed better performance for real case study and improved greatly with increase of cluster number than the other ones.

• Journal of the Korean Institute of Rural Architecture
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• 제8권3호
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• pp.17-26
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• 2006

As demands and interests in visiting rural village increases, government authorities are promoting eco and green tour village development project through plural functions of rural village. The purpose of this study is to understand infrastructure improvement direction by researching the case study of general rural villages' changing to eco and green tourism villages. As for the research method, the character of each village was verified, then the case studies of improvement by life infrastructure using the identity of villages were analyzed. Finally, it was found that infrastructure through public facilities improvement and environment improvement project was expanded and relaxative and experiential space was offered by creating tour infrastructure using the identity of villages. Also, it was shown that farming infrastructure creating project was executed to promote the income base of locals.

• Journal of the Korea Institute of Military Science and Technology
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• 제15권5호
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• pp.623-629
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• 2012

In this paper, we analysis the performance of position estimation when adopting Dynamic TDMA(DTDMA) in JTIDS RelNav. JTIDS RelNav is widely understood as a new navigation solution possibly capable to support or take cover of the role of conventional systems including INS or GPS no matter if they are working well or not. By maximizing the efficiency of radio resource management in MAC(Medium Access Control) layer we enhance the system performance without any replacement of hardware.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.452-452
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• 2008

Abstract Head-mounted displays(HMD) are being developed and marketed in growing numbers for a variety of applications. Though most commonly associated with entertainment applications other applications are also being developed. The field vision on the display screens is expanded by the optical system producing an imaginary screen that appears to be positioned several meters in front of the viewer. In this study, the mold core for the prism lens of HMD was processed by fly-cutting method, and the form accuracy of the mold core was measured.