• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.195-204
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• 2004

Poisson's ratio due to multiaxial creep of concrete reported by existing experimental works was controversial. Poisson's ratio calculated from measured strain is very sensitive to small experimental error. This sensitivity make it difficult to find out whether the Poisson's ratio varies with time or remain constant, and whether the Poisson's ratio has different value with stress states or not. A new approach method is needed to resolve the discrepancy and obtain reliable results. This paper presents analytical study on multiaxial creep test results. Microplane model as a new approach method is applied to optimally fitting the test data extracted from experimental studies on multiaxial creep of concrete. Double-power law is used as a model to present volumetric and deviatoric creep evolutions on a microplane. Six parameters representing the volumetric and deviatoric compliance functions are determined from regression analysis and the optimum fits accurately describe the test data. Poisson's ratio is calculated from the optimum fits and its value varies with time. Regression analysis is also performed assuming that Poisson's ratio remains constant with time. Four parameters are determined for this condition, and the error between the optimum fits and the test data is slightly larger than that for six parameter regression results. The constant Poisson's ratio with time is obtained from four parameter analysis results and the constant value can be used in practice without serious error.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.150-160
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• 2018

The purpose of this study is to classify the attitudes of Korean people regarding foreign workers and to analyze the influence factors. Analysis of the attitude difference and the influential factors utilized the SPSS ${\chi}^2$ test and multinomial logistic regression analysis using 2016 data obtained from the 'Koreans' Consciousness and Values'. Socio-demographic variables, national identity, and socioeconomic variables were used as explanatory variables. The attitude types (friendly, negative, and dual) of respondents were identified, and the influence of explanatory variables influencing these attitudes was identified. Analysis found they have a relatively generous stance on granting legal rights, while they are negative regarding the economic and social threats from foreign workers. As a result of analyzing the factors affecting attitudes, there are significant differences in each influence. However, negative attitudes and dual attitude concerning with negative legal rights found common to the influence of the factors of national identity. Gender and ratio of foreign workers were influential factors for dual attitudes with a high economic threat. On the other hand, socioeconomic factors reflecting the realistic conflict theory were not found to have any effect. The negative attitude of foreign workers in our society can be regarded as cognitive threats rather than realistic experiences or conflicts.

• Journal of Families and Better Life
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• v.12 no.1
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• pp.72-82
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• 1994

본 연구는 가정관리자의 관리유형과 가정생활 정보활용 수준 및 가족결속도간의 관 계규명을 위한 시도이며 서울시에 거주하는 자녀를 1명이상둔 주부를 대상으로 하였고 가정 생활주기별로 층화표집을 하였다. 배포한 설문지 중 기재미비로 제외된 나머지 704부를 연 구의 분석자료로 사용하였다 수집된 자료는 $Cronbach-{\alpha}$ 계수 요인분석, 빈도, 백분율, Anova, $x^2-test$, 회귀분석 및 경로분석과 판별분석의 통계방법을 적용하여 분석하였으며 SAS/PC program으로 처리하였다. 본 연구에서 설정한 가설은 부분적으로 긍정되었으며 연구결과를 요약하면 다음과 같다. 첫째 가정관리 유형에 유의적인 차이를 보인 변인은 주부의 학력, 남편의 학려그 자녀수, 결혼지속년수, 가정생활주기 및 시간지향이었다 이중에서 가정관리 유형을 판별해 낼 수 있는 변인은 주부학력과 시간지향변인이었다. 둘째 가정관리 유형별 qorudqusd니의 가족결속도에 대한 직.간접적인 영향력은 과업중심적 관리유형의 가정의 겨우 과거지향적인 주부일수록 남편학력이 높을수록 가정생활주기가 축소기에 가까우수록 전체 정보활용도는 높고 더불어 가족결속도도 높았다. 반변에 인간중심적 관리유형 가정의 경우 미래지향적인 주부일수록 학력이 높을수록 전체생활 정보활용도가 높고 더불어 가족결속도의 증대에 기여도가 높았다.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.187-197
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• 2013

Objectives : The purpose of this study was to analyze the effect of outpatient cost sharing reduction on health care utilization of children under 6 years old. Methods : The data in this analysis was the health insurance claims data between August 2006 and July 2008. The study group was divided into two age groups, namely 0-5 years old and 6-10 years old. This study evaluated the impact of policy change on office visits per person and expenditure per visit. In order to do so, the double difference analysis is used. Results: The results showed that outpatient cost-sharing reduction has never really had a huge impact on office visits per person and expenditure per visit. Conclusions: This study showed that the outpatient cost sharing reduction for children under 6 years old policy is not working. Therefore, cost sharing of National Health Insurance by income class is needed.

• Journal of the Korean Regional Science Association
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• v.36 no.3
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• pp.41-52
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• 2020

A new town attracts a large population in the short period due to its excellent residential conditions, and forms a local economy. However, if the new town is constructed in an inferior area, it would cause a negative effect to neighboring areas by absorbing population and firms from them. Nevertheless, the relocation of Chungnam provincial office from Daejeon, a metropolitan area to Naepo belongs to the key project of constructing Naepo. If the officers and their family members move to Naepo following the relocation and form a new consumer group of a local economy, the construction of Naepo would cause a positive effect to its neighboring areas. This paper empirically analyzes the effect of Naepo on the local economy through the change in differences of the new openings of restaurants between areas (defined either by donut-shaped area with 500-meter width or by Eup, Myun, and Dong) inside and those outside of 10km from the border of Naepo. The results from regression equation estimation where difference-in-differences framework is applied imply that the construction of Naepo new town caused a positive economic effect to its neighboring areas.

• Information Systems Review
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• v.23 no.1
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• pp.45-68
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• 2021

As the influence of online reviews on consumer decision-making increases, concerns about review manipulation are also increasing. Fake reviews or review manipulations are emerging as an important problem by posting untrue reviews in order to increase sales volume, causing the consumer's reverse choice, and acting at a high cost to the society as a whole. Most of the related prior studies have focused on predicting review manipulation through data mining methods, and research from a consumer perspective is insufficient. However, since the possibility of manipulation of reviews perceived by consumers can affect the usefulness of reviews, it can provide important implications for online word-of-mouth management regardless of whether it is false or not. Therefore, in this study, we analyzed whether there is a difference between the review evaluated by the consumer as being manipulated and the general review, and verified whether the manipulated review negatively affects the review usefulness. For empirical analysis, 34,711 online book reviews on the LibraryThing website were analyzed using multilevel logistic regression analysis and Poisson regression analysis. As a result of the analysis, it was found that there were differences in product level, reviewer level, and review level factors between reviews that consumers perceived as being manipulated and reviews that were not. In addition, manipulated reviews have been shown to negatively affect review usefulness.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.6
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• pp.50-59
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• 2015

This study aimed at suggesting Willingness To Pay (WTP) for introduction of the Traffic Accident emergency Call (TAC) system by using Contingent Valuation Method (CVM) which is a general valuation method. As the method, this study suggested a WTP estimation method of the TAC system with the double-bound dichotomous choice model. In previous studies, the data are processed differently according to the type of questions and analysis models used for the calculation of willingness to pay. Therefore, we re-organized the model by the cases using the truncated data sets, and showed the difference in WTPs. The dataset was developed by more than 500 questionnaire obtained from online and offline survey with the consideration of composition ratio by age group referring housing census in 2010 to mitigate regional bias of samples. At last, this study applied various statistical methods, survival analysis, multiple regression, and Tobit model for better interpretation of the questionnaires.

• Journal of Korean Society of Transportation
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• v.19 no.4
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• pp.19-33
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• 2001

In the developed countries, traffic noise is one of most serious problems faced by people's lives. So the importance of the traffic noise is quite well recognized by the infrastructure planners as well as the people. The traffic noise is valued in monetary terms in some countries and it is reflected in estimating the net present value or benefit/cost ratio. On the contrary, the effects of traffic noise are not reflected in the assessment of infrastructure in most cases in Korea. However, as the income level has been increasing, more people have been becoming to put more importance on their living conditions. The purpose of this paper is to estimate the value of traffic noise in the Seoul metropolitan area. The housing price were surveyed to use the quasi-hedonic price technique. By this way, two housing prices at the same floor level in different 128 complexes in the Seoul metropolitan area were surveyed. the actual traffic noise level was also measured. The differences of housing prices and noise levels were analyzed using the various types of regression models. The value is quite different by size of house. The value of large house is higher than that of small house. Since the income level of people in large house is higher than that in small house. it might be said that value of traffic noise for high income people is higher than that for low income people. Moreover, the increase of 1dB(A) noise affects the house price by about 0.3% in Seoul metropolitan area.

• Information Systems Review
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• v.24 no.2
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• pp.1-20
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• 2022

Researchers are making contradictory claims through the concept of superstars and long tails about how the development of IT technology affects demand distribution. Unlike previous studies that focused on changes in demand from a macro point of view, this study explored whether the relationship between a company's marketing activities and consumer response differs depending on the product location (i.e., superstar vs. long tail) from a micro point of view. Based on the marketing mix framework, hypotheses were developed based on the relevant literature. In the case of empirical analysis, 2,835 daily data from 63 Korean films were tested using the quantile regression method. As a result of the analysis, it was found that the influence of marketing mix factors on sales varies depending on the location of the product. Specifically, the appeal breadth of the film and the effect of owned media are enhanced in superstar products, and the effect of acquisition media in long-tail products is enhanced and the negative effects of competition are mitigated. Unlike previous studies that focused on macroscopic changes in demand distribution, this study suggested marketing activities suitable for practitioners through microscopic analysis.

• Journal of the Korean Data and Information Science Society
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• v.20 no.1
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• pp.139-148
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• 2009

The present study was conducted for analyzing changes in physique of at menarche of athletic and non-athletes. The maximum growth age of height and weight during menarche was not different between non-athletes and the athletes. Second, among non-athletes, those who had menarche late were taller and heavier than those who did early, and among the athletes, those who had menarche late were taller but lighter. The development rate of height was higher and the development duration was longer in the athletes than in the non-athletes. The development rate of weight was similar between the non-athletes and the athletes, but the maximum rate was higher in the athletes.