• Proceedings of the Korean Society for Quality Management Conference
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• 2006.11a
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• pp.309-314
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• 2006

The linear Consecutive-k-out-of-n:F system consists of n component ordered linearly and fail if and only if at least k consecutive components fail. We assume that the components are independent and identical exponentially distributed. This paper develops a model to calculate the expected cost per unit time of a linear consecutive-k-out-of-n:F system. The optimization problem we consider regards the choice of the system structure parameter k to minimized the expected cost per unit time.

• Journal of the Korean Operations Research and Management Science Society
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• v.17 no.2
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• pp.123-130
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• 1992

The model of k-out-of n : G repairable system with identical components is extended to a repairable system with n different components. The objective is to analytically derive the mean time of the busy period for a k-out-of-n : G system with unrestricted repair. Then, the lower and upper bounds on the average time of the busy period of the n-component system with restricted repair are also shown.

• Korean Journal of Community Nutrition
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• v.15 no.5
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• pp.687-693
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• 2010

This study investigated difference of general eating habit and eating-out behavior between men and women of university students in Gyonggi area. The survey was conducted from 1 March to 1 April 2010, in Gyeonggi area. Self-administered questionnaires were collected from 250 students in Gyeonggi area. The research results show, first of all, that they eat twice a day, and they usually do not eat breakfast. The main reason why they do not eat breakfast is that they do not have enough time to eat. Between men and women, there is significant difference in eating amount and eating speed at 0.001 levels. Men's problems of eating behavior are irregular meal time and speed of eating time, and in case of women, they do not have a meal regularly and overeat at one time. Second, they usually eat out for a meal and gather with friends once to three times a week. Also, the lunch set-menu promotion is the most preferred one. Third, when men choose a restaurant, they consider in order of taste, convenience, amount, and service; women consider in order of atmosphere, taste, convenience, and service. Taste is the most important for men; atmosphere is the most important consideration for women. Taste (at 0.01 levels), sanitation (at 0.05 levels), and atmosphere (at 0.001 levels) are significantly different between men and women in choosing restaurant.

• Journal of Korean Medical classics
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• v.22 no.3
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• pp.271-289
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• 2009

This thesis intend to help the eastern medical doctor to understand body condition from interpretation of perspirations(汗出) in daily time cycle. The conclusion is followed. 1. In most Eastern Medical classic and clinic literatures, the time of fever and perspirations are described as a result of disease's position at human body. Following this description, in daytime the perspirations must come from the Gi phase and night time the perspirations must come from the blood phase. Because in daytime the skin pores are opening and the defensive Gi is going out to the superficial portion of the body. In night time the skin pores are shutting and the defensive Gi is going in to the five solid organs. So a sweat in daytime comes out from the Gi phase and superficial portion of the body. And in night time comes out from the blood phase and five solid organs. But in recent real clinic cases, in daytime, there are so many perspirations from the five solid organs. Comparatively, the perspirations from the superficial portion of body are very little. And in same daytime perspirations, when the heat pathogens mixed with moist, the symptom revelation time delay to the afternoon. Therefore it can be concluded that the time of perspirations are combination of disease's Gi or blood phase and characteristics of pathogens. The position of disease at human body cannot simply judge the symptom revelation time. 2. The exchange of climate following time cycle of a day effect to the condition of human body. At same time it activates or not activates the pathogens in human body. So we can consider the kinds and characteristics of pathogens by distinguishing the symptom revelation time. In general differentiation of syndromes[辨證] pathogen's kinds and location are generally judged. By understanding the characteristics of pathogen, doctor can devise more correct and delicate prescription.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.04a
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• pp.121-128
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• 1999

This paper presents a time domain method for soil-structure interaction analysis for seismic loadings. It is based on the finite element formulation incorporating analytical frequency-dependent infinite elements for the far field soil. The dynamic stiffness matrices of the far field region formulated using the present method in frequency domain can be easily transformed into the corresponding matrices in time domain. At first, the equivalent earthquake forces are evaluated along the interface between the near and the far fields from the free-field response analysis carried out in frequency domain, and the results are transformed into the time domain. An efficient procedure is developed for the convolution integrals to evaluate the interaction force along the interface, which depends on the response on the interface at the past time instances as well as the concurrent instance. Then, the dynamic responses are obtained for the equivalent earthquake force and the interaction force using Newmark direct integration technique. Since the response analysis is carried out in time domain, it can be easily extended to the nonlinear analysis. Example analysis has been carried out to verify the present method in a multi-layered half-space.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.9
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• pp.1905-1913
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• 2002

Using the finite element method, this study investigates the dynamic time responses of a flexible spinning disk of which axis of rotation is misaligned with the axis of symmetry. The misalignment between the axes of symmetry and rotation is one of the major vibration sources in optical disk drives such as CD-ROM, CD-R, CD-RW and DVD drives. Based upon the Kirchhoff plate theory and the von-Karman strain theory, three coupled equations of motion for the misaligned disk are obtained: two of the equations are for the in-plane motion while the other is for the out-of-plane motion. After transforming these equations into two weak forms for the in-plane and out-of-plane motions, the weak forms are discretized by using newly defined annular sector finite elements. Applying the generalized-$\alpha$ time integration method to the discretized equations, the time responses and the displacement distributions are computed and then the effects of the misalign ment on the responses and the distributions are analyzed. The computation results show that the misalignment has an influence on the magnitudes of the in-plane displacements and it results in the amplitude modulation or the beat phenomenon in the time responses of the out-of-plane displacement.

• Culinary science and hospitality research
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• v.3
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• pp.23-40
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• 1997

This study has been made on the basis of the theoretical model of Beeker's time allocation concerning housewives' advance into society-- a primary cause for enlargint the scope of our food service market and developing the food service industry as a whole. The primary purpose of this study is to clarify the close relationship between housewives' activities in the course of allocating their time and the demand for the food service through Beeker's theory of“Total income and Total price”, analyzing the information obtained through the questionaires sent to the housewives in metropolitan areas. The result of the questionaires shows that the demand of food service is closely related to women's market activities. Yet it has become clear that the demand for food service correlates with housewives' allocation of time in terms of sharing profits. As a result, it is true that the increase in housewives' income per hour has brought about the increase of the term of employment and the decrease in their cooking time, thus greatly increasing the opportunities to dine out. In order words, the increase of housewives' income and the decrease in their cooking time have come to make a great contribution to shortening the time needed to take care of family matters while increasing the demand for eating out, or food service. And it is also clear that the common practice to dine out is derived from the reduction in our domestic duties, indicating the choice of social division of labour, but is needs to be noted that the gradual increase in women's income is sure to have exerted a considerable influence on this practice of eating out.

• Journal of Families and Better Life
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• v.9 no.2
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• pp.171-190
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• 1991

This study focused on time use and the influencing factors of employed wives. Its aims are specified as follows.:1) to figure out the tendency of time use spent on a holiday and weekday by employed wives ; (2) to find out factors influencing the amount of time in each domain spent on each day. The samples were composed for 396 employed wives living in Seoul and Kwangju city who had the eldest child less than 18years old. were sampled based on their work kind, work status, and residential quarter. The results are as follows; 1) Employed wives spend 423 minutes a weekday, and 513 minutes a holiday on the sleep and 522 minutes(weekday ), 618 minutes (holiday) on the total Physiological time 599 minutes (weekday), 72 minutes(holiday) were devoted to the employed time. compared to 214 minutes. 395 minutes for the housework Finally 103 minutes and 349 minutes were assigned to leisure time. Compared with the research results in Japan and the United States, this shows large difference. Korean wives; work time is excessively too long while the time for leisure and psysiological time is too short, which means the life style of Korean wives ti too simple and monotonous. 2) Social demographic variables(such as work status, education, income, wive's relative income rate, family type. family number, the younger child's age, and etc. )and variables connected with employment (such as employed work time and employment motivation) significantly differentiate the time use. A wive with higher education, employment status, and income level, spends more time for the psysiological , leisure time, and manegerial housework time, while spending less time for work and physical housework.

• Journal of the Korean Society of Food Culture
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• v.20 no.5
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• pp.548-553
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• 2005

The purpose of this study was to investigate eating-out behavior patterns of university students. A questionnaire survey was conducted on 610 university students(male : 41.5%, female: 58.5%). The main results are as follows: The motivation of eating out for the university students was the highest to take care of a meal, the second motivation was the social reason for the male student, but accomodate diversion for the female student. The time of eating-out was the highest from 31 minutes to 60 minutes. The eating-out cost of one time was highest from 5,000 won to 10,000 won. The eating-out cost of one month was the highest from 50,000 won to 100,000 won. The both male and female students were favorite of the korean foods. The left-over foods were higher female students compared with male students. The style of left-over foods was highest the korean foods. The payment style was high the most student by turns. The frequency of eating-out was high male students compared with female students as below (lunch>dinner>breakfast). The criteria for the selecting eating-out level was appeared as below (Taste>Cleanliness and hygiene>Kindness and good service>Price>Atmosphere>Variety of menu>Promptness of service>Convenient location>Quantity of food>Reputation). Both students liked hot tastes.

• Proceedings of the Korean Reliability Society Conference
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• 2000.11a
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• pp.387-395
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• 2000

Circular consecutive-k-out-of-n:F system when the failure of component is dependent is studied. We assume that the failure of a component in the system increase the failure rate of the survivor which is working just before the failed component. In this case, a mean time to failure (MTTF), a average failure number of the system, and the expected cost per unit time are obtained. Then the minimum number of consecutive failed components to cause system failure to minimize the expected cost per unit time is determined as searching paths to system failure. And various numerical examples are studied.