• Journal of Intelligence and Information Systems
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• v.11 no.2
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• pp.175-195
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• 2005

사례기반추론(case-based reasoning)은 사례간 유사도를 평가하여 유사한 이웃사례를 찾아내고, 이웃사례의 결과를 이용하여 새로운 사례에 대한 예측결과를 생성하는 전통적인 인공지능기법 중 하나다. 이러한 사례기반추론이 최근 적용이 쉽고 간단하다는 장점과 모형의 갱신이 실시간으로 이루어진다는 점 등으로 인해, 온라인 환경에서의 고객관계관리를 위한 도구로 학계와 실무에서 주목을 받고 있다 하지만, 전통적인 사례기반추론의 경우, 타 인공지능기법에 비해 정확도가 상대적으로 크게 떨어진다는 점이 종종 문제점으로 제기되어 왔다. 이에, 본 연구에서는 사례기반추론의 성과를 획기적으로 개선하기 위한 방법으로 유전자 알고리즘을 활용한 사례기반추론의 동시 최적화 모형을 제안하고자 한다. 본 연구가 제안하는 모형에서는 기존 연구에서 사례기반추론의 성과에 중대한 영향을 미치는 요소들로 제시된 바 있는 사례 특징변수의 상대적 가중치 선정(feature weighting)과 참조사례 선정(instance selection)을 유전자 알고리즘을 이용해 최적화함으로서, 사례간 유사도를 보다 정밀하게 도출하는 동시에 추론의 결과를 왜곡할 수 있는 오류사례의 영향을 최소화하고자 하였다. 제안모형의 유용성을 검증하기 위해, 본 연구에서는 국내 한 전문 인터넷 쇼핑몰의 구매예측모형 구축사례에 제안모형을 적용하여 그 성과를 살펴보았다. 그 결과, 제안모형이 지금까지 기존 연구에서 제안된 다른 사례기반추론 개선모형들은 물론, 로지스틱 회귀분석(LOGIT), 다중판별분석(MDA), 인공신경망(ANN), SVM 등 다른 인공지능 기법들에 비해서도 상대적으로 우수한 성과를 도출할 수 있음을 확인할 수 있었다.

• Nutrition Research and Practice
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• v.10 no.1
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• pp.74-80
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• 2016

BACKGROUND/OBJECTIVES: Cardiovascular diseases is a major cause of death and is responsible for 23.8% of deaths in Korea. Clinical symptoms manifest in adulthood, but susceptibility begins in utero. Elevated homocysteine levels and adiposity might be linked to a greater risk in children as well as adults. We hypothesized that those who have simultaneous risk for folate and adiposity would be affected with elevated homocysteine levels at 3 years of age. SUBJECTS/METHODS: From the ongoing birth cohort at Ewha Womans University Mok-Dong Hospital, we compared adiposity parameters, serum homocysteine, and folate levels in 238 children (118 boys and 120 girls) at three years of age. The relationship between birth outcome, current weight and body mass index (BMI), postnatal growth, and homocysteine level were assessed using correlation and general linear model. Additionally, we assessed the combined effect between blood folate status and adiposity on current homocysteine levels. RESULTS: Birth characteristics were not correlated with homocysteine. Current weight, BMI, upper-arm circumference, skinfold thickness, waist circumference, and hip circumference were positively correlated with homocysteine at three years of age (P < 0.05). Folate level was negatively correlated with homocysteine at three years of age (P < 0.0001). A relative high anthropometric measure which is compatible with adiposity and low folate level was associated with high homocysteine levels. CONCLUSION: We found a combined effect of adiposity and folate levels with homocysteine levels at three years of age. This implicates the beneficial role of folate supplementation in the high-risk population at an early age.

• Journal of the Korean Society of Child Welfare
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• no.40
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• pp.255-283
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• 2012

The purpose of this study is to examine the pathways of factors that influence adolescent's suicidal ideation of suicide attempters and non-attempters and to compare path coefficients between the two groups. Results from simultaneous analysis of multiple populations suggest that the path model was appropriate for both groups. However, significant differences in path coefficients were found. Parental abuse and peer victimization had direct effects on adolescent's suicidal ideation only among the adolescent suicide non-attempters. Burdensomeness and hopelessness had direct effects on adolescent's suicidal ideation, whereas thwarted belongingness did not have direct effects for both groups. Peer victimization appear to have an indirect effect through burdensomeness for both groups of adolescents. Only among the adolescent suicide non-attempters, parental abuse had an indirect effect on suicidal ideation through burdensomeness, and burdensomeness and thwarted belongingness had indirect effects on suicidal ideation through hopelessness. The results indicate that differentiated approaches are required to prevent suicidal ideation for adolescent suicide attempters and non-attempters.

• Smart Structures and Systems
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• v.18 no.3
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• pp.485-500
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• 2016

Stay cables in some cable-stayed bridges suffer large amplitude vibrations under the simultaneous occurrence of rain and wind. This phenomenon is called rain-wind-induced vibration (RWIV). The upper rivulet oscillating circumferentially on the inclined cable surface plays an important role in this phenomenon. However, its small size and high sensitivity to wind flow make measuring rivulet size and its movement challenging. Moreover, the distribution of the rivulet along the entire cable has not been measured. This paper applies the videogrammetric technique to measure the movement and geometry dimension of the upper rivulet along the entire cable during RWIV. A cable model is tested in an open-jet wind tunnel with artificial rain. RWIV is successfully reproduced. Only one digital video camera is employed and installed on the cable during the experiment. The camera records video clips of the upper rivulet and cable movements. The video clips are then transferred into a series of images, from which the positions of the cable and the upper rivulet at each time instant are identified by image processing. The thickness of the upper rivulet is also estimated. The oscillation amplitude, equilibrium position, and dominant frequency of the rivulet are presented. The relationship between cable and rivulet variations is also investigated. Results demonstrate that this non-contact, non-intrusive measurement method has good resolution and is cost effective.

• International Area Studies Review
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• v.13 no.3
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• pp.269-286
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• 2009

The aim of the paper is to study environmental impacts of openness and trade in korea, and analyze the relationships between trade, development and environment. This study established endogenous determinants such as inflow FDI, level of environmental pollution and economic growth, and assumed a proposition that each individual variables are in two-way relationships among the three key variables such as the openness, the environment and GDP. To estimate a system of equations, a simultaneous equation model is used because the simultaneity problems are formidable. The results show that the more openness and economic growth increase, the more level of environmental quality improve. This study also found that FDI and openness, and economic growth bring along the level of environmental quality.

• International Area Studies Review
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• v.13 no.3
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• pp.239-267
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• 2009

Investment in health through an array of public health policies will lead to improvement of health at all levels, and the improved health can reduce the socioeconomic costs incurred with diseases. And finally, with reduced healthcare costs associated with diseases and health problems, economy will be able to achieve economic growth and development. Using simultaneous equations model, this study aims to identify this possible channel from public health policies to economic growth. Specifically, the policy effect is investigated on a basis of main disease groups and aging groups. The public health policies are proved to reduce healthcare costs related with disease groups including respiratory, digestive, circulative, and infectious disease, and with all age groups except 20~39 group. And the reduced healthcare costs have shown to increase the real gross domestic products in those group above.

• The Journal of the Convergence on Culture Technology
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• v.5 no.3
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• pp.113-118
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• 2019

This study analyzed how interdependence between China, Hong Kong, Taiwan and Singapore stock markets changed after the implementation of Shanghai-Hong Kong Stock Connect system using the EGARCH-GED model that allow simultaneous analysis of return and variability. Since the implementation of this system, the interdependence of Taiwan stock market with the Greater China stock markets has been weakened, and the interdependence of Singapore's stock market with the Greater China stock markets has not been exist. On the other hand, he interdependence between China and Hong Kong stock markets has been shown to be significantly enhanced since the implementation of this system. This is appears to be the result of improved conditions for Chinese and Hong Kong investors to invest in the two stock markets following the implementation of this system. Thus, considering the portfolio investment in the Greater China stock markets, the investors will need to develop their investment strategies in light of these facts that the weakening interdependence of the Taiwan and Singapore securities markets and the strengthening interdependence of the Chinese and Hong Kong securities markets.

• Journal of the Korea Society of Computer and Information
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• v.24 no.4
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• pp.83-90
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• 2019

Is this paper, We propose to examined the relationship between advertising attributes and brand preference, consumer psychological repulsion, and consumer happiness. Due to the infinite competition between the companies, they are experiencing significant difficulties in operation. In this situation, effective advertising is obviously a very important means to overcome the difficulties of operation. Therefore, in order to maximize the advertising effect, sufficient awareness of the advertisement property and the production and exposure of the advertisement based on it can be very important. As such, the purpose of this study is to verify the effect of indirect advertising appearing on entertainment programs on consumers' preference for brands and their psychological resistance, and to verify the effect of consumers' preference for brands and psychological backlash on consumer happiness. In addition, the exposure pattern of indirect advertisement is intended to verify whether there is a control effect between the nature of the advertisement and the brand preference and psychological backlash. A total of 209 questionnaires were distributed to consumers who viewed program in order to achieve the purpose of this study. For empirical analysis, exploratory factor analysis, confirmatory factor analysis, frequency analysis, reliability analysis, structural equation model, and multimodal simultaneous comparison analysis were performed using SPSS V. 22.0 and AMOS V. 22.0. The results of the empirical analysis of this study are as follows. First, advertising attributes have a significant effect on brand preference. Second, the hypothesis that advertising attributes have a significant effect on psychological repulsiveness of consumers is partially adopted. Third, brand preference and psychological repulsion have a significant effect on consumer happiness. Fourth, we confirmed the moderating effect of PPL expression form in ad property, brand preference, and psychological repulsion. Based on these findings, we presented the implications, limitations and future research directions of the study.

• Journal of Information Technology Services
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• v.17 no.4
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• pp.101-117
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• 2018

Companies are responding appropriately to the rapidly changing business environment and striving to lead those changes. As part of that, we are meeting our strategic goals through IT projects, which increase the number of simultaneous projects and the importance of project portfolio management for successful project execution. It also strives for efficient deployment of human resources that have the greatest impact on project portfolio management. In the early stages of project portfolio management, it is very important to establish a reasonable manpower plan and allocate performance personnel. This problem is a problem that can not be solved by linear programming because it is calculated through the standard deviation of the input ratio of professional manpower considering the uniformity of load allocated to the input development manpower and the importance of each project. In this study, genetic algorithm, one of the heuristic methods, was applied to solve this problem. As the objective function, we used the proper input ratio of projects, the input rate of specialist manpower for important projects, and the equal load of workload by manpower. Constraints were not able to input duplicate manpower, Was used as a condition. We also developed a program for efficient application of genetic algorithms and confirmed the execution results. In addition, the parameters of the genetic algorithm were variously changed and repeated test results were selected through the independent sample t test to select optimal parameters, and the improvement effect of about 31.2% was confirmed.

• Structural Engineering and Mechanics
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• v.69 no.2
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• pp.193-204
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• 2019

This paper presents results from experimental and numerical studies on the response of steel-concrete composite box bridge girders under certain localized fire exposure conditions. Two composite box bridge girders, a simply supported girder and a continuous girder respectively, were tested under simultaneous loading and fire exposure. The simply supported girder was exposed to fire over 40% of its span length in the middle zone, and the two-span continuous girder was exposed to fire over 38% of its length of the first span and full length of the second span. A measurement method based on comparative rate of deflection was provided to predict the failure time in the hogging moment zone of continuous composite box bridge girders under certain localized fire exposure condition. Parameters including transverse and longitudinal stiffeners and fire scenarios were introduced to investigate fire resistance of the composite box bridge girders. Test results show that failure of the simply supported girder is governed by the deflection limit state, whereas failure of the continuous girder occurs through bending buckling of the web and bottom slab in the hogging moment zone. Deflection based criterion may not be reliable in evaluating failure of continuous composite box bridge girder under certain fire exposure condition. The fire resistance (failure time) of the continuous girder is higher than that of the simply supported girder. Data from fire tests is successfully utilized to validate a finite element based numerical model for further investigating the response of composite box bridge girders exposed to localized fire. Results from numerical analysis show that fire resistance of composite box bridge girders can be highly influenced by the spacing of longitudinal stiffeners and fire severity. The continuous composite box bridge girder with closer longitudinal stiffeners has better fire resistance than the simply composite box bridge girder. It is concluded that the fire resistance of continuous composite box bridge girders can be significantly enhanced by preventing the hogging moment zone from exposure to fire. Longitudinal stiffeners with closer spacing can enhance fire resistance of composite box bridge girders. The increase of transverse stiffeners has no significant effect on fire resistance of composite box bridge girders.