• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.9
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• pp.1423-1431
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• 2001

Based on the exponential intervening variable, a new two-point approximation method is presented. This introduces the shifting level into each exponential intervening variable to avoid the lack of def inition of the conventional exponential intervening variables due to zero-or negative-valued design variables. Then a new quadratic approximation whose Hessian matrix has only diagonal elements of different values is proposed in terms of these intervening variables. These diagonal elements are determined in a closed form that corrects the typical error in the approximate gradient of the TANA series due to the lack of definition of exponential type intervening variables and their incomplete second-order terms. Also, a correction coefficient is multiplied to the pre-determined quadratic term to match the value of approximate function with that of the previous point. Finally, in order to show the numerical performance of the proposed method, a sequential approximate optimizer is developed and applied to solve six typical design problems. These optimization results are compared with those of TANA-3. These comparisons show that the proposed method gives more efficient and reliable results than TANA-3.

• Journal of the Korean Society of Safety
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• v.36 no.3
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• pp.60-65
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• 2021

Human error is often in part in the cause of accidents and the result of various factors in an organization. Accidents should be investigated to elucidate all causes. Therefore, to reduce accidents, it is necessary to identify which factors affect human error within the organization. In this study, five groups of influencing factors on human error were selected using previousresearch, and operational definitions were made based on them. In addition, a questionnaire for measuring latent variables by operational definition was developed as an observation variable, and responses were received from employees of chemical companies in Ulsan. Based on SEM (structural equation modeling) analysis, 1) confirmatory factor analysis of variables in the human error model, 2) reliability and validity of latent variables, 3) correlations among latent variables, 4) influencing coefficients among influence factors, and 5) the verification results of the paths that these influencing factors have on human error are introduced in this study.

• Industrial Engineering and Management Systems
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• v.15 no.2
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• pp.143-147
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• 2016

Uncertainty appears not only in real quantities but also in complex quantities. Complex uncertain process is essentially a sequence of complex uncertain variables indexed by time. In order to describe complex uncertain process, a formal definition of complex uncertain distribution is given in this paper, as well as the concepts of independence and variance. In addition, some properties of complex uncertain integral are presented.

• Journal of Korea Society of Digital Industry and Information Management
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• v.17 no.1
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• pp.57-73
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• 2021

The purpose of this study is to analyze the diffusion period and productivity of smartwork in an organization. Firms are increasingly interested in smartwork for non contact work and working from home because of the corona 19. The smartwork is a new technology that changes face-to-face work in an organization. It helps the work of individuals and organizations regardless of time and place. The theoretical background describes the complexity, system thinking, diffusion theory, smart work, organizational resistance, and productivity. This study analyzes the diffusion period and productivity of smart work through business simulation techniques. A simulation study progresses four stages. There are problem definition, hypothesis establishment and causal loop diagram, model construction and verification, and policy evaluation. The simulation models contain an individual's resistance variables organizational investment and leadership variables related to the operation of smartwork. The organizational investment variables include organizational culture, legal system, implement systems and technology investment. The individual resistance variables include cognitive, attitude, structure and technological resistance. The leadership includes leadership interest variables and performance linkage variables. The simulation executed the changes of a people number adopting smart work and the organizational productivity monthly. As a result of the simulation, many organization members have accepted the smart work innovation after 20 months. The organizational productivity through smart work showed very high value after 16 months. In scenario analysis, the individuals' awareness and attitude resistance showed very important variables to productivity and a personal change of smart work adoption. Meanwhile, The organizational investment showed that the high driving-force increased not productivity and the low driving-force showed decreased low productivity. Also, leadership variables showed a powerful driver for changing smart work productivity. The implication of the study has suggested extending complexity, diffusion theory and organization resistance theory based on simulation methods.

• Journal of Korean Society for Quality Management
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• v.47 no.3
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• pp.537-552
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• 2019

Purpose: The development of information technology makes it easy to utilize high-dimensional categorical data. In this regard, the purpose of this study is to propose a novel method to select the proper categorical variables in high-dimensional categorical data. Methods: The proposed feature selection method consists of three steps: (1) The first step defines the goodness-to-pick measure. In this paper, a categorical variable is relevant if it has relationships among other variables. According to the above definition of relevant variables, the goodness-to-pick measure calculates the normalized conditional entropy with other variables. (2) The second step finds the relevant feature subset from the original variables set. This step decides whether a variable is relevant or not. (3) The third step eliminates redundancy variables from the relevant feature subset. Results: Our experimental results showed that the proposed feature selection method generally yielded better classification performance than without feature selection in high-dimensional categorical data, especially as the number of irrelevant categorical variables increase. Besides, as the number of irrelevant categorical variables that have imbalanced categorical values is increasing, the difference in accuracy between the proposed method and the existing methods being compared increases. Conclusion: According to experimental results, we confirmed that the proposed method makes it possible to consistently produce high classification accuracy rates in high-dimensional categorical data. Therefore, the proposed method is promising to be used effectively in high-dimensional situation.

• The Korean Journal of Community Living Science
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• v.15 no.4
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• pp.45-60
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• 2004

The purpose of this study was to set related variables for leadership measurement in the leader of a community organization as an effort to Community development constantly. Therefore, in this study, first, various theories on leadership were reviewed. Second, approaches and variable relationships were reviewed by leadership theory study. Third, leadership measurement variables were set based on Bass's Transformational theory, one of new trend theory, to measure the leadership of the community organization leader. As a follow up, clear and scientific analysis, through empirical analysis, based on the variables set in this study will be made to measure leadership of a community organization after creating investigation tools based on the variables set in this study A literature study was mainly used. 'Human Behavior' by Dr Han-geom Lee, 'Leadership Theory' by Eung-seop Shin, many other related books, articles of the Human Relation Organization Association, and theses and Bass's writings. Major findings of this study, through the literature study, were as follows. As conventional leadership theories, characteristics theory, behavior theory and situational leadership theory were proposed. First, characteristics theory searches the characteristics of an effective leader. It proposes that effective leaders and ineffective leaders have different characteristics, respectively. Therefore, it proposes to study the leader's characteristics. However, there is not a flexed definition for leader's characteristics. Scholars make different definition on leader's characteristics, and they are very subjective. Thus it cannot be a valid theory. Second, behavior theory describes how the leader behaves to his fellows. It studies leader's behavior focusing on what type and what combination is the most effective in all situations. However, it has weakness in that it focuses on a leader's behavior only, and ignores the situational features. Third, situational theory describes the relationship between leadership type and situation. It suggests that there is not a single leadership style that can suit all situations. It emphasizes the relationship between leadership type and situation. Although situational theory considers more variables than characteristics theory or behavior theory, it also sees situations as static and flxed. Although Fiedler's theory tried to comply with situations, he did not analyze interactions between a leader and his fellows.

• The Journal of Korean Association of Computer Education
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• v.13 no.2
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• pp.1-14
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• 2010

Previous researches on the improvement of logical thinking in Informatics subject have used general logical thinking test and only limited improvement of logical thinking by programming learning result. In this study, the operational definition of the logical thinking in problem-solving process on Informatics education is different from the general logical thinking and the logical thinking of the other subjects. Firstly, we suggested the operational definition of components of logical thinking using the open questionnaire by expert and research team discussion. Also, we suggested the relationship between the operational definition and contents of the 'problem-solving methods and procedure' section in secondary Informatics subject. Finally, this study developed the evaluation contents based on the operational definition of components of logical thinking. The components of logical thinking which was required in problem-solving process on Informatics subject were ordering reasoning, propositional logic, controlling variables, combinatorial logic, proportional reasoning. We suggested the relationship between operational definition and problem-solving process and assessment of logical thinking in problem-solving process on Informatics subject. This paper will give meaningful insight to supply the guideline of the teaching strategy and evaluation methods for improving the logical thinking in Informatics education.

• Journal of the Korean Home Economics Association
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• v.39 no.2
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• pp.41-56
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• 2001

The purpose of this study is to find the general trends of sexual harassment at workplace and to investigate the differences of related variables. The data were obtained through 880 employee living in Chonbuk-Province. The major findings were as follows-1) 70.3% of respondent reported that they had experienced the victimization of sexual harassment at workplace at least once. But most respondents reacted passively to the sexual harassment. 2) Most respondents perceived broadly the definition of sexual harassment and attributed sexual harassment to the social structure. The level of perception about the existence of the institution and the law for the sexual harassment problem was low. 3) The most important variable in the experience of sexual harassment was the ideology of sex-role division. 4) The more respondents experienced sexual harassment, the more they demanded the preventive education of sexual harassment .

• Journal of the Korean Society of Earth Science Education
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• v.7 no.2
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• pp.180-191
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• 2014

The purpose of this study was to determine the effects on STEAM education for intergrated science inquiry ability of high school students. The experimental and control group were 30 students, respectively. The STEAM program developed by a teacher study group was applied to the experimental group students for 6 months. The control group learned traditional methods. The results of this study showed that the intergrated science inquiry ability of experimental group students were increased positively(P<0.05). Also the abilities as hypothesis, defining variables, determining variables, operational definition and data interpretation improved affirmatively(P<0.05) except graphing.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.7
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• pp.940-947
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• 2004

In this paper, an optimum design problem for endosseous implant in dentistry is studied to find best implant design. An optimum design problem is formulated to reduce stresses arising at the cortical as well as cancellous bones, in which sufficient design parameters are chosen for design definition that encompasses major implants in popular use. Optimization at once (OAO) with the large number of design variables, however, causes too costly solution or even failure to converge. A concept of multilevel optimization (MLO) is employed to this end, which is to group the design variables of similar nature, solve the sub-problem of smaller size for each group in sequence, and this is iterated until convergence. Each sub-problem is solved based on the response surface method (RSM) due to its efficiency for small sized problem.