• Earthquakes and Structures
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• v.7 no.6
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• pp.1061-1070
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• 2014

An iterative hybrid structural dynamic reliability prediction model has been developed under multiple-time interval loads with and without consideration of stochastic structural strength degradation. Firstly, multiple-time interval loads have been substituted by the equivalent interval load. The equivalent interval load and structural strength are assumed as random variables. For structural reliability problem with random and interval variables, the interval variables can be converted to uniformly distributed random variables. Secondly, structural reliability with interval and stochastic variables is computed iteratively using the first order second moment method according to the stress-strength interference theory. Finally, the proposed method is verified by three examples which show that the method is practicable, rational and gives accurate prediction.

• Korean Journal of Rural Living Science
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• v.7 no.1
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• pp.51-67
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• 1996

The purpose of this study was to empirically verify the influence of socio-demographic variables, leisure motivation, and leisure barriers on leisure participation of married women, and provide a basis for the development of leisure education. The subject of this study were 422 married women and interviewed with a questionnaire. The data were analyzed by SPSS/PC＋ program for the frequency, mean, standard deviation, Crdnbach's $\alph$$\alpha$ , and regression. The major results of this study were as follows: 1. The score of self-developmental motivation, time and expenses barriers, which was the highest among the other variables. Married women frequently participate in time spending activities. 2. Frequencies of leisure participation differ according to socio-demographic variables, leisure motivation and leisure barriers. 3. The score of relative contribution of leisure barriers on leisure participation was the highest among the other variables.

• Journal of the Korean Home Economics Association
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• v.24 no.4
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• pp.93-104
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• 1986

The purpose of this study was to see that how about the related variables influence on the use of the microwave oven and how about the use of the microwave oven influence on the time spent in meal preparation and meal management. Questionaires were give to randomly selected homaker's, in kwangju in August, 1986. Data from the 149 response were analyzed according to multiple regression. The results were as follows; 1. The variables affecting the use of the microwave oven were family income, homaker's employed hours, homakers' education level, a period of use a microwave oven, congnition of a special character in a microwave oven, family style of participation in meal preparation, frequency in use of instant food. 2. The variables of the use the microwave oven was significantly influence on the time spent in meal preparation. 3. The variables of the use the microwave oven was not significantly influence on meal management.

• Journal of Families and Better Life
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• v.11 no.2
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• pp.83-95
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• 1993

This study investigated time management behavior of employed wives and variables related. The samples were composed of 396 wives living in Seoul and Kwangju city. The major finding are as follow: 1) The level of the time management of employed wives was slightly high. 2) The dominant factor in time management behavior was goal setting and planning$.$priori-ting 3) The time management behavior was low related to the time use. A negative relationship was found between time management behavior and psysiological time employed time psysical housework time and passive leisure time while a positive relationship was found managerial housework time and active leisure time 4) A employed wife with higher work status education and income level efficiently managed time Education and extend family type turned out facilitating factors the more employed time was found constraint factor in time management.

• Journal of the Ergonomics Society of Korea
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• v.22 no.3
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• pp.57-73
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• 2003

Although body pressure distribution is sensitive to movements and is relatively simple to measure even in small space, there are few researches involving applications to driver's posture and its change. The main objective in this study is the application of body pressure distribution measurements for the prediction of the driver's posture and its change. This requires quantitative analyses of the dynamic body pressure distribution, which is the change of body pressure distribution with time. The experiment involved 16 male subjects who drove for 45 minutes in a seating buck. Measurement time, stature group, and lumbar support prominence were selected as independent variables, with subjective ratings of driver's discomfort, body posture data of hip, torso. knee angle, and body pressure data variables as dependent variables. The body pressure change variables and subjective ratings were found to increase as the measurement time increased and body pressure ratio variables reflected the torso angle. From the results and analysis of the body posture data and subjective rating results, it was predicted that the seats and the design of the lumbar supports used in the experiment was not fit for tall subjects, which could also be confirmed through the body pressure distribution data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.2
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• pp.166-173
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• 2004

The new way of doing education in cyber space is not limited by time or locations. The students do not need to attend classroom physically on time. Networked computers allow students to study their subjects at any time and any where. This study tries to probe the relationships among demographic variables and instructional variables with students satisfaction in the management education. Pervious studies found out that the critical success factors of cyber educations are based on the demographic and instructional variables. The results of the study demonstrate that demographic variables are not significantly related with students satisfaction. Rather instructional variables such as personal interactions with professors, job related contents and careful reduction of difficulties countered during the class proceeding are more significantly related with learning satisfaction. The result shows the newly emerged internet based education system requires in-depth collaborations and coordination among professors, system engineers, education instrument designers, and students.

• Human Ecology Research
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• v.53 no.6
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• pp.641-654
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• 2015

This study identifies and tracks changes gender differences in adolescent users' problematic online behavior. This study used Korea Youth Panel Survey (KYPS), which has tracked respondents over 7 years, with self-control theory and social learning theory applied as a theoretical framework. The model included individual-level variables such as self-control and respondent's experience of problematic behavior (offline), as well as socialization variables such as the number close friends who engaged in problematic offline behavior, parent-child relationships, and parental monitoring. Dependent variables included problematic online behavior, unauthorized ID use (ID theft) and cyberbullying (cursing/insulting someone in a chat room or on a bulletin board). Control variables consisted of academic performance, time spent on a computer, monthly household income, and father's educational attainment. Random and fixed effects models were performed by gender. Results supported self-control theory even for the within-level analysis (fixed effects models) regardless of gender, while social learning theory was partially supported. Only peer effects were found significant (except for unauthorized ID use) among girls. Year dummy variables showed significant negative associations; however, academic performance and time spent using computers were significant in some models. Father's educational attainment and monthly household income were found insignificant, even in the random effects models. We also discuss implications and suggestions for future research and policy makers.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.95-98
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• 1996

Universal Learning Network(U.L.N.), which can model and control the large scale complicated systems naturally, consists of nonlinearly operated nodes and multi-branches that may have arbitrary time delays including zero or minus ones. Therefore, U.L.N. can be applied to many kinds of systems which are difficult to be expressed by ordinary first order difference equations with one sampling time delay. It has been already reported that learning algorithm of parameter variables in U.L.N. by forward and backward propagation is useful for modeling, managing and controlling of the large scale complicated systems such as industrial plants, economic, social and life phenomena. But, in the previous learning algorithm of U.L.N., time delays between the nodes were fixed, in other words, criterion function of U.L.N. was improved by adjusting only parameter variables. In this paper, a new learning algorithm is proposed, where not only parameter variables but also time delays between the nodes can be adjusted. Because time delays are integral numbers, adjustment of time delays can be carried out by a kind of random search procedure which executes intensified and diversified search in a single framework.

• Bulletin of the Korean Chemical Society
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• v.27 no.10
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• pp.1659-1663
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• 2006

A many-body master equation is constructed by incorporating stochastic terms responsible for chemical reactions into the many-body Smoluchowski equation. Two forms of Langevin-type of memory equations describing the time evolution of dynamical variables under the influence of time-independent perturbation with an arbitrary intensity are derived. One form is convenient in obtaining the dynamics approaching the steady-state attained by the perturbation and the other in describing the fluctuation dynamics at the steady-state and consequently in obtaining the linear response of the system at the steady-state to time-dependent perturbation. In both cases, the kinetics of statistical averages of variables is found to be obtained by analyzing the dynamics of time-correlation functions of the variables.

• Journal of the Korean Institute of Gas
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• v.5 no.1
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• pp.21-28
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• 2001

Expert system for automating HAZOP analysis of batch processes In contrast with continuous processes must consider the discrete variables such as time and sequence. So in this study, we have developed the expert system for automating HAZOP analysis of batch processes to analyse time and sequence on the basis of the relation between discrete variables and continuous ones. Because these variables can not be explained by the method used in the HAZOP analysis of continuous processes. The proposed expert system have been discussed on a Latex batch process to evaluate its effectiveness.