• 제목/요약/키워드: Multiple Objectives

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Comparison of students' foodservice satisfaction between Korea and US

  • Jeong, Eunkyung;Chun, Youngah;Joo, Nami;Yoon, Ji-Young
    • Nutrition Research and Practice
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    • 제7권1호
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    • pp.66-71
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    • 2013
  • This study analyzes important factors of foodservice in school through comparison of students' satisfaction of using foodservice in Korea and US in order to meet students' expectations. The survey was composed of 4 categories including menu, service, hygiene, and facility and it was carried out in both countries to evaluate satisfaction. First, comparison of satisfaction between two countries was made using t-test. Secondly, multiple regression was performed to identify factors affecting satisfaction. As a result Korean students were more satisfied than American students in all aspects. However, regardless of nationality, the top three factors affecting the students' satisfaction were the same. The predictors were food taste (Korean 0.375 and American 0.350), menu variety (Korean 0.305 and American 0.278), and service line (Korean 0.226 and American 0.192). Despite the similarity of the predicators, it can be concluded that the difference in satisfaction level between the two nationscan be explained by the approaches to create comfortable and acceptable changes in schools' foodservice. Korea has been increasing the foodservice quality based on their objectives to provide students comfortable and positive environment when eating nutritious meals. However, US have made their main objectives on making changes to decrease youth obesity. Foodservice improvements according to continuous evaluations and surveys are necessary in order to increase students' satisfaction.

유입량의 변동성을 고려한 Fuzzy DEA 기반의 댐 군 연계운영 가중치 대안 평가 (An Evaluation of Multi-Reservoir Operation Weighting Coefficients Using Fuzzy DEA taking into account Inflow Variability)

  • 김용기;김재희;김승권
    • 산업공학
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    • 제24권3호
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    • pp.220-230
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    • 2011
  • The multi-reservoir operation problem for efficient utilization of water resources involves conflicting objectives, and the problem can be solved by varying weight coefficient on objective functions. Accordingly, decision makers need to choose appropriate weight coefficients balancing the trade-offs among multiple objectives. Although the appropriateness of the weight coefficients may depend on the total amount of water inflow, reservoir operating policy may not be changed to a certain degree for different hydrological conditions on inflow. Therefore, we propose to use fuzzy Data Envelopment Analysis (DEA) to rank the weight coefficients in consideration of the inflow variation. In this approach, we generate a set of Paretooptimal solutions by applying different weight coefficients on Coordinated Multi-reservoir Operating Model. Then, we rank the Pareto-optimal solutions or the corresponding weight coefficients by using Fuzzy DEA model. With the proposed approach, we can suggest the best weight coefficients that can produce the appropriate Pareto-optimal solution considering the uncertainty of inflow, whereas the general DEA model cannot pinpoint the best weight coefficients.

Auxiliary domain method for solving multi-objective dynamic reliability problems for nonlinear structures

  • Katafygiotis, Lambros;Moan, Torgeir;Cheungt, Sai Hung
    • Structural Engineering and Mechanics
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    • 제25권3호
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    • pp.347-363
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    • 2007
  • A novel methodology, referred to as Auxiliary Domain Method (ADM), allowing for a very efficient solution of nonlinear reliability problems is presented. The target nonlinear failure domain is first populated by samples generated with the help of a Markov Chain. Based on these samples an auxiliary failure domain (AFD), corresponding to an auxiliary reliability problem, is introduced. The criteria for selecting the AFD are discussed. The emphasis in this paper is on the selection of the auxiliary linear failure domain in the case where the original nonlinear reliability problem involves multiple objectives rather than a single objective. Each reliability objective is assumed to correspond to a particular response quantity not exceeding a corresponding threshold. Once the AFD has been specified the method proceeds with a modified subset simulation procedure where the first step involves the direct simulation of samples in the AFD, rather than standard Monte Carlo simulation as required in standard subset simulation. While the method is applicable to general nonlinear reliability problems herein the focus is on the calculation of the probability of failure of nonlinear dynamical systems subjected to Gaussian random excitations. The method is demonstrated through such a numerical example involving two reliability objectives and a very large number of random variables. It is found that ADM is very efficient and offers drastic improvements over standard subset simulation, especially when one deals with low probability failure events.

한국과 미국의 정신건강 정책목표 비교 (Comparative Study on Mental Health Policy Goal in Korea and America)

  • 이현경;정은기;장안기;이종일
    • 보건교육건강증진학회지
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    • 제26권1호
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    • pp.159-170
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    • 2009
  • The purpose of this study was to review national mental health policy goal in Korea and America, and to suggest strategies for advancing the national mental health policy in Korea. Objectives: First, the review of nation mental health policy in Korea. Second, the review of nation mental health policy in America. Third, the development of nation mental health plan in Korea. Methods: To achieve this objectives, review the books, journals, and national published papers and so on. Results: First, 15 goals are planned for mental health promotion in Korea Health Plan 2010. Second, 14 goals and multiple strategies are planned for mental health promotion in America Healthy People 2010. Third, 3 plans are suggested for mental health promotion in Korea. Conclusion: Mental Health is essential dimension in holistic health. And mental health promotion has been increasingly emphasized in national health plan. Therefore, effective nation mental health policy establishment would be needed continuously.

중학생들의 인지수준과 과학교과 내용과의 관계 분석 (Relationships Between the Cognitive Levels of Students and Understanding of Concrete and Formal Science Content)

  • 최병순;허명
    • 한국과학교육학회지
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    • 제7권1호
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    • pp.19-32
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    • 1987
  • The primary purpose of this study was to assess understanding of concrete and formal operational science content by concrete and formal operational students in secondary school physical science classes. To carry out this study subjects were selected from junior high schools of over 2500 students, and they were identified as concrete, transitional, or formal operational using GALT(Group Assessment of Logical Thinking) developed by Roadrangka, Yeany and Padilla(1983). Instructional objectives were extracted from the science content taught during the second term of the academic year in the 7th, 8th and 9th grade, and they were classified as concrete or formal operational. Written test involving those objectives were constructed and administered. The results of this study suggested that formal operational thought brought deeper understanding to concrete science content as well as formal science content. Differential effects by sex on understanding of both concrete and formal science content were contradictory through the grade levels. Results of multiple comparison tests suggested that students categorized as formal operational demonstrated no better understanding of concrete science content than those categorized as transitional. However, they demonstrated better understanding of formal science content.

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순위가 있는 가중치 평균 방법에서 일정한 수준의 결합력을 갖는 가중치 함수의 성질 및 다기준의사결정 문제에의 활용 (The Ordered Weighted Averaging (OWA) Operator Weighting Functions with Constant Value of Orness and Application to the Multiple Criteria Decision Making Problems)

  • 안병석
    • Asia pacific journal of information systems
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    • 제16권1호
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    • pp.85-101
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    • 2006
  • Actual type of aggregation performed by an ordered weighted averaging (OWA) operator heavily depends upon the weighting vector. A number of approaches have been suggested for obtaining the associated weights. In this paper, we present analytic forms of OWA operator weighting functions, each of which has such properties as rank-based weights and constant value of orness, irrespective of number of objectives aggregated. Specifically, we propose four analytic forms of OWA weighting functions that can be positioned at 0.25, 0.334, 0.667, and 0.75 on the orness scale. The merits for using these weights over other weighting schemes can be mentioned in a couple of ways. Firstiy, we can efficiently utilize the analytic forms of weighting functions without solving complicated mathematical programs once the degree of orness is specified a priori by decision maker. Secondly, combined with well-known OWA operator weights such as max, min, and average, any weighting vectors, having a desired value of orness and being independent of the number of objectives, can be generated. This can be accomplished by convex combinations of predetermined weighting functions having constant values of orness. Finally, in terms of a measure of dispersion, newly generated weighting vectors show just a few discrepancies with weights generated by maximum entropy OWA.

Factors contributing to participation in food assistance programs in the elderly population

  • Hong, Seo Ah;Kim, Kirang
    • Nutrition Research and Practice
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    • 제8권4호
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    • pp.425-431
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    • 2014
  • BACKGROUND/OBJECTIVES: The study objectives were to examine the participation rate in food assistance programs and explore the factors that contribute to such participation among the Korean elderly population. SUBJECTS/METHODS: The study sample comprised 3,932 respondents aged 65 years or older who were selected from a secondary data set, the fourth Korean Welfare Panel Study (KoWePS). The factors, related to participation in programs were examined based on the predisposing, enabling and need factors of the help-seeking behavior model. Multiple logistic regression analysis was used to select the best contributors among the factors related to program participation. RESULTS: The predisposing rate in food assistance programs was 8.5% (7.1% for men and 10.4% for women). When all variables were included in the model, living without spouse, no formal education, low income, having social security benefits and food insecurity in elderly men, and age, low income, having social security benefits and feeling poor in elderly women were significantly related to a higher tendency to program participation. CONCLUSIONS: The predisposing and need factors, such as living without spouse, low education level, food insecurity and feeling poor were important for program participation, as well as enabling factors, such as household income and social security benefits. A comprehensive approach considering these factors to identify the target population for food assistance programs is needed to increase the effectiveness and target population penetration of these programs.

Task Assignment Strategies for a Complex Real-time Network System

  • Kim Hong-Ryeol;Oh Jae-Joon;Kim Dae-Won
    • International Journal of Control, Automation, and Systems
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    • 제4권5호
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    • pp.601-614
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    • 2006
  • In this paper, a study on task assignment strategies for a complex real-time network system is presented. Firstly, two task assignment strategies are proposed to improve previous strategies. The proposed strategies assign tasks with meeting end-to-end real-time constraints, and also with optimizing system utilization through period modulation of the tasks. Consequently, the strategies aim at the optimizationto optimize of system performance with while still meeting real-time constraints. The proposed task assignment strategies are devised using the genetic algorithmswith heuristic real-time constraints in the generation of new populations. The strategies are differentiated by the optimization method of the two objectives-meeting end-to-end real-time constraints and optimizing system utilization: the first one has sequential genetic algorithm routines for the objectives, and the second one has one multiple objective genetic algorithm routine to find a Pareto solution. Secondly, the performances of the proposed strategies and a well-known existing task assignment strategy using the BnB(Branch and Bound) optimization are compared with one other through some simulation tests. Through the comparison of the simulation results, the most adequate task assignment strategies are proposed for some as system requirements-: the optimization of system utilization, the maximization of running tasktasks, and the minimization of the number of network node nodesnumber for a network system.

The Balancing of Disassembly Line of Automobile Engine Using Genetic Algorithm (GA) in Fuzzy Environment

  • Seidi, Masoud;Saghari, Saeed
    • Industrial Engineering and Management Systems
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    • 제15권4호
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    • pp.364-373
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    • 2016
  • Disassembly is one of the important activities in treating with the product at the End of Life time (EOL). Disassembly is defined as a systematic technique in dividing the products into its constituent elements, segments, sub-assemblies, and other groups. We concern with a Fuzzy Disassembly Line Balancing Problem (FDLBP) with multiple objectives in this article that it needs to allocation of disassembly tasks to the ordered group of disassembly Work Stations. Tasks-processing times are fuzzy numbers with triangular membership functions. Four objectives are acquired that include: (1) Minimization of number of disassembly work stations; (2) Minimization of sum of idle time periods from all work stations by ensuring from similar idle time at any work-station; (3) Maximization of preference in removal the hazardous parts at the shortest possible time; and (4) Maximization of preference in removal the high-demand parts before low-demand parts. This suggested model was initially solved by GAMS software and then using Genetic Algorithm (GA) in MATLAB software. This model has been utilized to balance automotive engine disassembly line in fuzzy environment. The fuzzy results derived from two software programs have been compared by ranking technique using mean and fuzzy dispersion with each other. The result of this comparison shows that genetic algorithm and solving it by MATLAB may be assumed as an efficient solution and effective algorithm to solve FDLBP in terms of quality of solution and determination of optimal sequence.

반도체 산업 노동자 암 발생 위험 논란과 과제 (Challenges and issues of cancer risk on workers in the semiconductor industry)

  • 박동욱
    • 한국산업보건학회지
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    • 제29권3호
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    • pp.278-288
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    • 2019
  • Objectives: The objectives of this study are to summary controversy over health risks among semiconductor workers, to review major cancer risk results conducted in semiconductor operation and to evaluate occupational health activities in Korea for controlling hazardous agents generated in semiconductor operations Methods: Major occupational health issues that has been social controversies among semiconductor workers since 2007 were reviewed through an extensive literature, report and article review. Results: Since a female semiconductor worker aged 22 died from leukemia in 2007, job-association of a number of former semiconductor workers with various types of cancer and rare diseases have been denied by the Korea Workers' Compensation and Welfare Service (KWCWS), but some of them were later awarded compensation as an occupational disease by the administrative court. Two epidemiologic cancer risk studies conducted in Korea found increased risks in leukemia and non-Hodgkin's lymphoma among semiconductor workers. Various legal occupational health activities taken in semiconductor industry were found to fail to assess a complex characteristics of semiconductor operations, such as drastic changes in chemical use, processes, and technology, multiple exposure. National compensation regulation also showed the limitation to evaluate job-association of semiconductor workers who had worked in semiconductor operation. Conclusions: National legal measures should be taken to improve several occupational health activities and duties for protecting workers. In addition, the KWCWS program should be revised so that all workers who meet minimal job or environment associations can be compensated.