• International Journal of Fluid Machinery and Systems
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• 제3권4호
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• pp.324-331
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• 2010

Cavitation in cryogenic fluids generates substantial thermal effects and strong variations in fluid properties, which in turn alter the cavity characteristics. In order to investigate the cavitation characteristics in cryogenic fluids, numerical simulations are conducted around an axisymmetric ogive in liquid nitrogen and hydrogen respectively. The modified Merkle cavitation model and energy equation which accounts for the influence of cavitation are used, and variable thermal properties of the fluid are updated with software. A good agreement between the numerical results and experimental data are obtained. The results show that vapor production in cavitation extracts the latent heat of evaporation from the surrounding liquid, which decreases the local temperature, and hence the local vapor pressure in the vicinity of cavity becomes lower. The cavitation characteristics in cryogenic fluids are obtained that the cavity seems frothy and the cavitation intense is lower. It is also found that when the fluid is operating close to its critical temperature, thermal effects of cavitation are more obviously in cryogenic fluids. The thermal effect on cavitation in liquid hydrogen is more distinctively compared with that in liquid nitrogen due to the changes of density ratio, vapour pressure gradient and other variable properties of the fluid.

• 유통과학연구
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• 제11권4호
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• pp.51-60
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• 2013

Purpose - The objective of this paper is to investigate the effect of asset specificity, the level of information sharing, the importance of information sharing, and an integrated collaborative environment on supply chain performance. Research design, data, and methodology - Data collection was implemented as follows: questionnaires were distributed to 250 companies that have business ties with Halla Climate Control Corporation. The empirical study to test our hypothesis was based on statistical analysis (using SPSS 18.0 and AMOS 18.0). The hypothesis of this paper is that the asset specificity variable has positive effects on the following variables: Level of information sharing, the importance of information sharing, and integrated collaborative environment. Moreover the variables, the level of information sharing, and the importance of information sharing are strongly influenced by the variable integrated collaborative environment, and these when combined, have an effect on the dependent variable, supply chain performance. We tested our hypothesized model utilizing path analysis with latent variables. Results - According to the results of our analysis, hypothesis H1, which tests whether there is a relationship between asset specificity and the integrated collaborative environment, is supported at the 0.01 level. Hypotheses H2 and H3 were also confirmed, and asset specificity had positive effects (+) on the level of information sharing variable. The importance of the information sharing variable was statistically significant at the 0.01 level. Hypotheses H4 and H5 posited that the integrated collaborative environment variable would have a positive effect on the level of information sharing; the importance of information sharing variable was strongly supported statistically, with a significant p-value below. Moreover, the level of information sharing (H6), and the importance of information sharing (H7) variables also had a statistically relevant influence on supply chain performance. As a result, existence of a collaborative system between companies would influence supply chain performance by strengthening real-time information access and information sharing. Thus, it is important to construct a collaborative environment where information sharing among companies and cooperation is possible. Conclusions - First, with rapid changes in the business environment, it becomes necessary for enterprises to acquire the right information in order to properly implement SCM. For successful SCM, firms should understand the importance of collaboration with supply chain partners and an internally built collaboration system, which in turn will better promote a partnership commitment with suppliers as well as collaborative integration with buyers. A collaborative system, as we suggest in this paper, facilitates the maintenance of a long-term relationship of trust, and can help reinforce information sharing. Second, it is necessary to increase information sharing over time via a collaborative system so that employees of the suppliers become aware of the system. The more proactive and positive attitudes are towards such a collaborative system by the managerial group, the higher the level of information sharing will be among the users. Successful SCM performance is achieved by information sharing through a collaborative environment rather than by investing only in setting up an information system.

• 대한가정학회지
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• 제37권10호
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• pp.107-122
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• 1999

Based on the theoretical framework of the Double ABCX model of family stress and adaptation, this study was to analysis the causal relationships of stressors (psychological sexual, and physical wife abuse), personal resources (self-efficacy and self-esteem) and social support(emotional and informational support), appraisal(positive appraisal and downward comparisons) with adaptation (psychological well-being and somatic symptoms). Self-administered questionnaire method was used to collect data from 264 wives residing in Chonbuk-do and Kyonggi-do area. The causal model was tested and modified by the maximum likelihood method using UISREL 7 program. Results showed that wife abuse had effect on adaptation indirectly through the latent variables of personal resource and appraisal, which influenced the adaptation directly. In addition, social support indirectly affect the adaptation through personal resource and appraisal. It was also found that all these variables explained 27.6% of the total variance of wives'adaptation, and that personal resources was the most powerful variable in predicting the adaptation of the wives.

• Journal of the Korean Statistical Society
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• 제28권3호
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• pp.311-324
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• 1999

The problem of 'outliers', observations which look suspicious in some way, has long been one of the most concern in the statistical structure to experimenters and data analysts. We propose a model for an outlier problem and also analyze it in linear regression model using a Bayesian approach. Then we use the mean-shift model and SSVS(George and McCulloch, 1993)'s idea which is based on the data augmentation method. The advantage of proposed method is to find a subset of data which is most suspicious in the given model by the posterior probability. The MCMC method(Gibbs sampler) can be used to overcome the complicated Bayesian computation. Finally, a proposed method is applied to a simulated data and a real data.

• 한국IT서비스학회지
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• 제10권2호
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• pp.203-221
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• 2011

The purpose of this study is to investigate the applications of Structural Equation Modeling(SEM) into MIS area in recent years. Two methodologies, Lisrel and PLS, are adopted for the method comparison. A research model, based upon TAM(Technology Acceptance Model) is used for the analysis of the data set of a previous study. The research model includes six research variables that are composed of twenty-eight question items. 272 data are used for data analyses through Lisrel v.8.72 and Visual PLS v.1.04. This study shows the statistical results of Lisrel are the same to those of PLS. The contribution of this study can be suggested as the followings; (1) A theoretical comparison of two methodologies is shown, (2) A statistical analysis is done at a real-situated data set, and (3) Several implications are suggested.

• Communications for Statistical Applications and Methods
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• 제8권3호
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• pp.805-814
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• 2001

The problem of 'outliers', observations which look suspicious in some way, has long been one of the most concern in the statistical structure to experimenters and data analysts. We propose a model for outliers problem and also analyze it in linear regression model using a Bayesian approach with the variance-inflation model. We will use Geweke's(1996) ideas which is based on the data augmentation method for detecting outliers in linear regression model. The advantage of the proposed method is to find a subset of data which is most suspicious in the given model by the posterior probability The sampling based approach can be used to allow the complicated Bayesian computation. Finally, our proposed methodology is applied to a simulated and a real data.

• Journal of Information Technology Applications and Management
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• 제23권3호
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• pp.25-34
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• 2016

Often we receive misled conclusion in the research if properly variables are not analyzed. In different functional issues of management it is very essential that all the latent and observed variable are properly understood so management decisions will be relevant and effective. The objective of this paper is to investigate the use of different multivariate tools for analyzing in the management research : applied or basic. The sources of data is primary as well as secondary. The primary includes the observation of different research articles of the proceedings of different conferences. And the secondary includes different publications related to multivariate analysis. The study has revealed the reasons of not using such tools of research. The preliminary finding reveals that most of the researches do not use such analytical tools in a comprehensive manner. Carelessness in design while fixing the design aspect is the main reasons of not using appropriate design.

• 에너지공학
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• 제7권1호
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• pp.122-130
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• 1998

A simplified heat transfer model for the cooling capability of the AP 600 PCCS is proposed I this paper. As the PCCS domain is covered with very thin and long water film, it is phenomenologically divided into 3 regions; water entrance effect region, asymptotic region, and air entrance effect region. As the length of the asymptotic region is estimated to be over 90% of the whole domain, the phenomena in the asymptotic region is focused. Using the analogy between heat and mass transfer phenomena in a turbulent situation, a new dependent variable combining temperature and vapor mass fraction was defined. The similarity between the PCCs phenomena in the asymptotic region and the buoyant air flow phenomena on a vertical heated plate is derived. Using the similarity, the simplified heat transfer correlations for the interfacial heat fluxes and the ratios of latent heat transfer to sensible heat transfer were established. To verify the accuracy of the correlation, the results of this study were compared with those of other numerical analyses performed for the same configuration and they are well within the range of 15% difference.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2006년도 한국컴퓨터종합학술대회 논문집 Vol.33 No.1 (A)
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• pp.40-42
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• 2006

유전자 발현에 있어서의 조절작용은 유전자간의 복합적인 상호작용의 결과에 기인한다. 따라서 이러한 현상으로부터 기능적으로 연관된 유전자 군을 식별하기 위해서는 단일 유전자보다는 복수의 유전자군의 발현패턴을 대상으로 하게 된다. 이 경우 발현패턴의 시간에 따른 다양하고 복잡한 특징들은 은닉변수학습 모형을 이용하므로서 보다 명확하게 표현될 수 있고, 유사한 기능을 가진 유전자 군을 탐색 하는데에 효과적으로 이용될 수 있다. 본 논문에서 제시된 은닉변수학습 모형은 이스트 Cell Cycle 데이터에 적용한 결과 특정 조절유전자에 대하여 생물학적으로 연관된 유전자 군을 찾는 데에 다른 방법과 비교하여 효과적임을 보일 수 있었다.

• 한국식물병리학회지
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• 제13권2호
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• pp.85-89
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• 1997

Etiological components of the rice cultivars possessing durable resistance to rice blast were evaluated. In the greenhouse test by artificial inoculation, number of leaf blast lesion in Dongjinbyeo was not increased by any race of the pathogen, while the lesion number on the resistant cultivar Palgongbyeo and susceptible cultivar Jinmibyeo was increased rapidly. Size of the lesion in Dongjinbyeo was smaller and progressed more slowly than the resistant cultivar Palgongbyeo until 11 days after inoculation. Latent period in Dongjinbyeo was intermediate. However, the period was significantly variable depending upon the races. Least amount of conidia was produced in Dongjinbyeo by race KJ-107 and the number of conidia was decreased rapidly from 11 days after inoculation.