• Bulletin of the Korean Space Science Society
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• 2002.10a
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• pp.76-76
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• 2002

• Journal of Preventive Medicine and Public Health
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• v.30 no.2 s.57
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• pp.413-427
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• 1997

This research is based on the Consumption Values Theory proposed by Sheth(1991). The purpose of this research is finding the factors related to the process of hospital choice. The expectation of six hospital outpatients 600 was analyzed by six consumption values categories: functional value, social value, emotional value, rarity value, condition value, health related values. The main results of this research is as following; 1. In the result of factor analysis 22 consumption value factors which affect the hospital preference were extracted; kindness/clearness, service speed, comfort of space, technical competence in functional values, high income/active social life, low income/blue collar unmarried/man, middle aged/big family, woman/married, introvert in social values, high-class, comfort, reliability in emotional value, newness, classiness in rarity value, social relationship, close to residence, social reputation in conditional values, priority on health, health behavior, active sense of value on health in health related values. 2. The difference of consumption values among hospital types were analyzed. The critical factors in reference for corporate hospitals newly established were kindness/clearness, service speed, convenience, classiness, comfort, and newness. University hospitals were preferred by the factors of reliability, and social reputation. In general hospital, convenience and close to residence were critical factor. 3. In logistic regression, age, marital status, education level and income as socio-demographic variables were significantly related to general hospital choice. Also service speed and close to residence were positively and high income/active social life and high class value were negatively related to general hospital choice. On university hospital choice, age and marital status, education show posive relationship whereas income showing negative relationship. Kindness/clearness, service speed, comfort of space, unmarried/man, comfortable feeling, newness and close to residence showed negative relationship with university hospital selection whereas technical competence, reliability in emotional value, classiness in rarity value, social relationship in functional values showed positive relationship. Lastly kindness/clearness, comfort of space, high income/active social life, unmarried/man, high-class, comfort and newness were positively related to corporate hospitals newly established choice in contrast to negative relationship in reliability in emotional value and classiness. In summary, we found that hospital user also choose to hospital in base of various consumption value. Further studies to investigate the hospital consumer behavior will be needed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.4
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• pp.334-340
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• 2015

Engine derating is often considered for reliability benefits because lower power operation reduces its failure probability. To be derated during operation, however, the engine must be initially overdesigned. The engine overdesign is cost effective only if reliability increased from derating is enough to offset the initial increase in the development cost caused from the overdesign. The purpose of this paper is to provide an analytical model to consider a trade-off between the engine overdesign and derating. We use a logistic regression model to explain reliability growth in the number of hot firing tests for a fixed power level. Using the Transcost model with the reliability growth model, we show that 10% overdesign of Titan rocket engine decreases its development cost by about 9% and 23% depending on the reliability requirement. We also point out that such a cost reduction depends on the fuel type a rocket uses.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.12
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• pp.1048-1058
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• 2017

One of the failure mechanism of spaceborne electronics is a fatigue fracture on solder joint under launch random vibration. Thus, a necessity of early diagnosis through the fatigue life evaluation on solder joint arises to prevent such potential risk of failure. The conventional life prediction methods cannot assure the accuracy of life estimation results if the packaging type changes, and also requires much time and effort to construct the analysis model of highly integrated PCB with various packaging types. In this study, we performed life prediction of PCB based on a reliability and life prediction tool of sherlock as a new approach for evaluating the structural reliability on solder joint, and those prediction results were validated by fatigue tests. In addition, we also investigated an influence of solder height on the fatigue life of solder joint. These results indicated that the Sherlock is applicable tool for evaluating the structural reliability of spaceborne electronic.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.4
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• pp.336-345
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• 2012

In crack growth life, uncertainties are caused by variance of geometry, applied loads and material properties. Therefore, the reliability estimation for these uncertainties is required to keep the robustness of calculated life. The stress intensity factors are the most important variable in crack growth life calculation, but its equation is hard to know for complex geometry, therefore they are processed by the finite element analysis which takes long time. In this paper, the response surface is considered to increase efficiency of the reliability analysis for crack growth life of a turbine wheel. The approximation model of the stress intensity factors is obtained by the regression analysis for FEA data and the response surface of crack growth life is generated for selected factors. The reliability analysis is operated by the Monte Carlo Simulation for the response surface. The results indicate that the response surface could reduce computations that need for reliability analysis for the turbine wheel, which is hard to derive stress intensity factor equation, successfully.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.3
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• pp.98-108
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• 1999

The purpose of this research is to help outdoor space planning reflected real needs of apartment residents in the differentiation elements of outdoor space, by using USC trade-off game in three apartment complexes in Seoul. This game method was used to evaluate their preference, reliability of preference degree, satisfaction degree, requirement elements such as improvement, sacrifice, maintenance of present condition, and payment possibility for improving and maintaining present condition, in addition to their preference and payment possibility of differentiation of outdoor space in the apartment complex in the future. From the statical analysis, we found the following results: 1. Reliability of preference degree was valid, inasmuch as the first elements they preferred were the almost same as the last things. 2. Elements of preference were pedestrian ways, pedestrian security facilities, various athletic facilities, and variety and high-class facilities in a play ground. 3. Satisfaction degree of differentiation elements of outdoor space was low not only in total complexes but also in each complex. As a result of analysis, these elements were not satisfied with residents. 4. Most of the differentiation elements of outdoor space in three apartment complexes, except planting traditional trees, were required to improve and maintain present condition. The cost to improve and maintain these elements able to pay by them was about 2.18 million won. Through this result, these elements were not options but prerequisites for planning outdoor space in apartment complexes. 5. In the future preference elements of differentiation of outdoor space in apartment complexes were pedestrian and jogging ways, places with water, various athletic places and facilities, multi-function resting places, green spaces in experiences, pedestrian security facilities, various athletic facilities, variety and high-class facilities in a play ground, and payment possibility for these elements was about 3.20 million won.

• Publications of The Korean Astronomical Society
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• v.31 no.2
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• pp.11-19
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• 2016

This paper presents the results of test observations toward a point source, 4C39.25, for observation modes with various bandwidths and numbers of IF streams in order to examine a reliability of the Daejeon hardware correlator performance for correlating VLBI (Very Long Baseline Interferometry) data obtained with the several observation modes of the KVN (Korean VLBI Network). We used a DiFX software correlator (DiFX) as a reference, for investigating the output visibilities from the Daejeon corelator. It is found that the band shapes of the output visibilities from two correlators are similar to each other and the correlated flux density for each baseline obtained from the Daejeon hardware correlator is lower by 3 - 7% than that from the DiFX. The flux difference is attributed to the limitation of FPGA resources and the difference of fringe rotation algorithm of the Daejeon hardware correlator. The conversion factor, 0.93 ~ 0.97, is proposed for future correlation with the Daejeon hardware correlator.

• 시스템엔지니어링워크숍
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• s.6
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• pp.39-42
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• 2005

• Journal of Korean Society for Quality Management
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• v.35 no.2
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• pp.99-105
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• 2007

Most of systems used in real fields are considered as multistate systems with multistate components. As one of methods for performance evaluation of the system, reliability analysis has been popularly used. In this paper, we propose an improved reliability analysis method which is based on state space decomposition method of Aven (1985). In deriving upper bounds, our method uses sets of unspecified states whereas Aven (1985) excludes sets of unacceptance states. Also, closer lower bounds to an exact reliability are obtained by considering of importance of min-path vectors.

• Structural Engineering and Mechanics
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• v.37 no.5
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• pp.543-560
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• 2011

In structural engineering there are randomness inherently exist on determination of the loads, strength, geometry, and so on, and the manufacturing of the structural members, workmanship etc. Thus, objective and constraint functions of the optimization problem are functions that depend on those randomly natured components. The constraints being the function of the random variables are evaluated by using reliability index or performance measure approaches in the optimization process. In this study, the minimum weight of a space truss is obtained under the uncertainties on the load, material and cross-section areas with harmony search using reliability index and performance measure approaches. Consequently, optimization algorithm produces the same result when both the approaches converge. Performance measure approach, however, is more efficient compare to reliability index approach in terms of the convergence rate and iterations needed.