• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.10
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• pp.457-463
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• 2001

This paper presents a simple and new digital redesign algorithm for fuzzy-model-based controllers. In the first stage, a continuous-time TS fuzzy model is constructed for a given continuous-time nonlinear system and a corresponding continuous-time fuzzy-model-based controller is established based on the existing controller synthesis algorithms. In the second stage, the continuous-time fuzzy-model-based controller is converted to equivalent discrete-time fuzzy-model-based controller, aiming at maintaining the property of the analogue controlled system, which are called intelligent digital redesign. Finally, the proposed method is applied to the digital control of inverted pendulum system to shows the effectiveness and the effectiveness and the feasibility of the method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.2
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• pp.201-206
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• 2019

Rejuvenating a system periodically during the most idle time of the system reduces unexpected downtime caused by software aging and increases its availability. In general, software rejuvenation can be largely divided into two broad categories: time-based rejuvenation policy and condition-based rejuvenation policy. In time-based rejuvenation policy the software rejuvenation is triggered at scheduled time epochs with fixed time intervals, while in condition-based rejuvenation policy the software rejuvenation is performed when system state is checked to satisfy a specific condition. Conditionbased policy adds extra cost to the system due to system monitoring and aging estimation. This paper presents a stochastic model for analyzing time-based software rejuvenation mechanism, where the rejuvenation is triggered at scheduled time epochs with fixed time intervals, and provides an analytical solution for the steady-state availability, the user-perceived availability, and the corresponding cost.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5D
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• pp.739-746
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• 2006

The bus probe-based link travel times were more readily available due to bus' fixed route schedule and it was different from that of taxi-based one in its value for the same link. At the same time, the bus-based one showed less accurate information than the taxi-based link travel time, in terms of reliability expressed by 1-RMSE(%) measure. The purpose of this thesis is to develop a heuristic algorithm for mixing both sources-based link travel times. The algorithm used both real-time and historical profile travel times. Real-time source used 4 consecutive periods' average and historical source used average value of link travel time for various congestion levels. The algorithm was evaluated for Seoul urban arterial network 3 corridors and 20 links. The results based on the developed algorithm were superior than the mere fusion based link travel times and the reliability amounted up to 71.45%. Some limitation and future research agenda have also been discussed.

• Journal of KIISE:Software and Applications
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• v.30 no.10
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• pp.944-954
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• 2003

People are experiencing severe problems in temporal navigation as time-based contents and platforms become more popular Relatively limited research, however, has been conducted on temporal navigation compared to that on spatial navigation. This research aims to identify efficient temporal navigation aids for time-based contents. It proposes Time Navigator, a new temporal navigation system based on the episodic indexing theory, and evaluates its efficiency through two experiments with a computer-based simulator for digital TV The video contents of digital TV was focused on because it is one of the most representative time-based contents and platforms. Our results indicate that Time Navigator helps people navigate time -based contents more effectively. Its effects increase as the contents include more narratives.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.5
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• pp.957-964
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• 2011

New time schemes based on the FEM were developed and their performances were tested with 2D wave equation. The least-squares and weighted residual methods are used to construct new time schemes based on traditional residual minimization method. To overcome some drawbacks that time schemes based on the least-squares and weighted residual methods have, ad-hoc method is considered to minimize residuals multiplied by others residuals as a new approach. And variational method is used to get necessary conditions of ad-hoc minimization. A-stability was chosen to check the stability of newly developed time schemes. Specific values of new time schemes are presented along with their numerical solutions which were compared with analytic solution.

• Journal of Korean Institute of Industrial Engineers
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• v.33 no.3
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• pp.355-363
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• 2007

This paper presents a method of an automatic work time evaluation based on the verification of a disassemblability and assembly configuration. Even though a work time evaluation is an important field of concern for planning assembly lay-out, there are some limitations using cumbersome user query or approximated work time data without considering assembly condition. To overcome such restriction, this paper presents a method to mathematically verify assembly conditions based on the disassemblability, which is defined by the separability and stability cost. The separability cost represents a facility of the part disassembly operation, and the stability cost which represents a degree of the stability for the base assembly motion. Based upon the results, we propose a new approach of evaluating work time using neural networks. The proposed method provides an effective means of solving the work time evaluation problem and gives a design guidance of planning assembly lay-out in flexible manufacturing application. Example study is given to illustrate the concepts and procedure of the proposed schemes.

• Korean Management Science Review
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• v.24 no.1
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• pp.113-126
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• 2007

This paper deals with a mathematical approach for finding the time-fractions for the time-fraction based scheduling method in multimedia wireless networks. By introducing a constraint that regulates the performance fairness amongst users, we present a systematic method for harmonizing both the system and user performance. Numerical results show that the time-fraction based scheduling method reinforced with our scheme is very effective especially in multimedia environments.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.36
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• pp.333-340
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• 1995

In Manufacturing using time-based strategies, as a competitive advantage, time is the equivalent of productivity, quality, innovation. In addition, time-based sourcing's impact on competiveness is not limited to cost control but also influences the performance of its adoption. This paper is to examine the relation between the level of time-recognition and supporting and performance of time-based sourcing by the empirical study.

• Journal of the Korean Home Economics Association
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• v.39 no.3
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• pp.47-66
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• 2001

The purpose of this study is to find the difference of household/work characteristics, family life satisfaction, and work satisfaction between home-based workers and out-of-home workers. The data of this study was collected from 230 married womens(home-based worker : 103 cases out-of-home worker : 127 cases) living in seoul. The major findings of the study are as follows. 1) Home-based worker's consumption expenditure structure, wive's housework time, schedule flexibility and degree of interruption, work loads were significantly higher than out-of-home workers. 2) Home-based worker's average monthly wage of her own and work time were significantly lower than out-of-home jokers. 3) Home-based worker's child care satisfaction and time use satisfaction were significantly higher than out-of-home workers. Out-of-home worker's self-fulfillment satisfaction, satisfaction of relation with supervisor, job stability satisfaction, work time satisfaction was significantly higher than home-based workers.

• Journal of the Korean Home Economics Association
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• v.39 no.6
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• pp.25-40
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• 2001

The purpose of this study was to find out the amount of the household work time related to food and examine the factors affecting the time accomplished by married female home-based workers and on-site workers. The data were collected from 165 married female home-based workers, and 292 married female on-site workers in Pusan and Kyungnam province, by the self-administered questionnaire. frequency distributions, Cronbach's alpha, t-tests, Pearson's correlations, and multiple regression analyses were conducted by SPSS/PC+. The major findings of this study were as follows: (1) both married female home-based and on-site workers spent more time on household work related to food in a weekend than in a weekday, (2) in a weekday, occupation was significantly related to the amount of time that married female home-based workers spent on food household work, whereas age and occupation were significant for married female on-site workers, (3) on Saturday, the significant factors of the time spent on food household work were the number of family and occupation for married female home-based workers, and educational level, occupation, sex role attitude, existence of children of 6 years or under, and existence of elders/disability within the family for married female on-site workers, and (4) on Sunday, for married female home-based workers, the number of family, occupation, and the level of market good substitution had significant effects on the amount of time spent on food household work, and for married female on-site workers, age, the number of family, occupation, sex role attitude, work hours on Sunday, and the level of market good substitution were significant.