• Journal of Korean Society of Transportation
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• v.20 no.4
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• pp.135-150
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• 2002

The basic assumption of analytical Dynamic Traffic Assignment models is that traffic demand and network conditions are known as a priori and unchanging during the whole planning horizon. This assumption may not be realistic in the practical traffic situation because traffic demand and network conditions nay vary from time to time. The rolling horizon implementation recognizes a fact : The Prediction of origin-destination(OD) matrices and network conditions is usually more accurate in a short period of time, while further into the whole horizon there exists a substantial uncertainty. In the rolling horizon implementation, therefore, rather than assuming time-dependent OD matrices and network conditions are known at the beginning of the horizon, it is assumed that the deterministic information of OD and traffic conditions for a short period are possessed, whereas information beyond this short period will not be available until the time rolls forward. This paper introduces rolling horizon implementation to enable a multi-class analytical DTA model to respond operationally to dynamic variations of both traffic demand and network conditions. In the paper, implementation procedure is discussed in detail, and practical solutions for some raised issues of 1) unfinished trips and 2) rerouting strategy of these trips, are proposed. Computational examples and results are presented and analyzed.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.169-185
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• 2017

Given that nowadays things get very fast due to the pervasive use of the Internet and mobile devices, decision-making time can be an important variable in the online economic decisions. Although in experimental and behavioral economics, measures like scores or earnings are usually preferred, this study argues that the time variable can be dealt with as a new decision outcome. Thus, by selecting some psychological factors presumably impactful in the online context (i.e., incidental emotions, psychological distances, and individual's impulsivity), this study tested their effect on decision time in the online centipede game. As a result, the mean decision time in the game was longer (1) in the happiness condition than in the anger condition and (2) in the friend condition than in the stranger condition. The people with attention difficulties spent a short time in the decision and the people who dislike complex problems spent a short time in explaining their decision. This study can contribute to the field as it used the decision time as the dependent variable and it tested the effect of psychological factors in the context of online decision-making. Future studies can be conducted in other online decision situations or by considering other psychological variables.

• The Journal of Korean Philosophical History
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• no.54
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• pp.43-75
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• 2017

This paper is to examine how Joseon intellectuals understood $g{\check{u}}$(古) and $j{\bar{i}}n$(今) and how its history consequently changed. It is to take a macroscopic view focusing on differences of different schools. Understanding of '$g{\check{u}}$' and '$j{\bar{i}}n$' directly and indirectly affected academia, art and even politics throughout Joseon dynasty. As different scholars and schools distinctively understood $g{\check{u}}$ and $j{\bar{i}}n$, issues of tradition and creation; conservatism and progressivism and; ideal and reality were deeply discussed. Those discussions greatly and historically contributed to making changes in politics and society as well. A cultural tradition of emphasizing '$g{\check{u}}$' took a deep root in overall Joseon society. Meanwhile, understanding of '$j{\bar{i}}n$(今)' or '$x{\bar{i}}n$(新)' was required with changes of times. as When people thought the reality is confusing or corrupt, they adopted restoration(復古) which means to go back to basis as the slogan. Awareness in $g{\check{u}}$ and $j{\bar{i}}n$ served as a drive to change the society. However, they never lifted their voices for '$j{\bar{i}}n$' or '$x{\bar{i}}n$,' abandoning '$g{\check{u}}$'. Criticism on '$g{\check{u}}$' was merely for criticizing being bound by '$g{\check{u}}$,' not targeting '$g{\check{u}}$' itself. '$J{\bar{i}}n$' actually was a dependent variable of '$g{\check{u}}$.' It is a dichotomous view to consider '$g{\check{u}}$' as conservatism and '$j{\bar{i}}n$' as progressivism.

• Journal of dental hygiene science
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• v.12 no.1
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• pp.7-13
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• 2012

Critical thinking is a essential competency for dental hygiene education and practice. The purpose of this study was to examine critical thinking disposition between groups classified by GPA score in two dental hygiene educational program. A total 252 dental hygiene students responded. The study extracted six dimensions(intellectual eagerness/curiosity, prudence, healthy skepticism, intellectual integrity, objectivity, self-confidence) derived from 27 items with the exception of systematicity using factor analysis. The mean score for critical thinking disposition was 3.47 on a 5 point scale. The result showed a statistically significant correlation critical thinking disposition and age. Multivariate analysis of covariance(MANCOVA) was used to compare six subscales between the three groups. MANCOVA results revealed that intellectual eagerness/curiosity for three groups were significantly different(Wilks's lamda=0.914, F(6, 24)=1.869), p=0.01, partial eta square=0.044). Multiple comparison for intellectual eagerness/curiosity by Scheffe's method showed differences between high score group and mid score group(p=0.027), high score group and low score group(p=0.002). In this study, academic achievement and critical thinking tends to show significant correlations is known. Critical thinking skills by examining the actual grade compares the difference in propensity scores according to a case study in intellectual curiosity, passion, and could tell the difference to appear.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.759-764
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• 2011

This study was conducted to provide the basic data for the health management of the primary school, by finding and analyzing the factors affecting the degrees of atopic dermatitis symptom's severeness. The subjects of our study were collected 273 pupils mothers, whose children are undergoing through the atopic symptoms. The investigation process took the entire month of the November in 2006. The result of the older the pupils, the severer their symptoms(p<0.05). The longer the period(p<0.01), the more widely spread over the body, and the severer the symptoms(p<0.01). In the dietary habit, the more meat they eat, the severer the symptom(p<0.05). and in relation to the eating the food outside home, the more frequently they eat the fast-food, the severer the symptom. In the multiple logistic regression analysis, using the degrees of atopic dermatitis symptom's severeness as the dependent variables. it is discovered that the longer infection period they have and the more frequently they have the fast-food, the severer the symptom of the atopic dermatitis. The parent's love for the child, the monthly cost for the management of the infection, and the parent's feeling toward the child, can have a greate influence on the physical health, the feelings and the relation with the friends of the infected child, when the child shows the symptoms of scratching his skin. The conclusions of When all the results above are put together, the dietary habit of eating the meals mostly prepared with the meat should be corrected, and the education to form the pupil's right dietary habit, such as, putting the limit on the fast-food, must be made, in order to prevent the symptom of the atopic dermatitis from getting worse. And by the recognizing the atopic dermatitis as the family health problem, the comprehensive family health management, including the mother should be made.

• KDI Journal of Economic Policy
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• v.12 no.2
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• pp.51-79
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• 1990

Research on technical efficiency, an important dimension of market performance, had received little attention until recently by most industrial organization empiricists, the reason being that traditional microeconomic theory simply assumed away any form of inefficiency in production. Recently, however, an increasing number of research efforts have been conducted to answer questions such as: To what extent do technical ineffciencies exist in the production activities of firms and plants? What are the factors accounting for the level of inefficiency found and those explaining the interindustry difference in technical inefficiency? Are there any significant international differences in the levels of technical efficiency and, if so, how can we reconcile these results with the observed pattern of international trade, etc? As the first in a series of studies on the technical efficiency of Korea's manufacturing industries, this paper attempts to answer some of these questions. Since the estimation of technical efficiency requires the use of plant-level data for each of the five-digit KSIC industries available from the Census of Manufactures, one may consture the findings of this paper as empirical evidence of technical efficiency in Korea's manufacturing industries at the most disaggregated level. We start by clarifying the relationship among the various concepts of efficiency-allocative effciency, factor-price efficiency, technical efficiency, Leibenstein's X-efficiency, and scale efficiency. It then becomes clear that unless certain ceteris paribus assumptions are satisfied, our estimates of technical inefficiency are in fact related to factor price inefficiency as well. The empirical model employed is, what is called, a stochastic frontier production function which divides the stochastic term into two different components-one with a symmetric distribution for pure white noise and the other for technical inefficiency with an asymmetric distribution. A translog production function is assumed for the functional relationship between inputs and output, and was estimated by the corrected ordinary least squares method. The second and third sample moments of the regression residuals are then used to yield estimates of four different types of measures for technical (in) efficiency. The entire range of manufacturing industries can be divided into two groups, depending on whether or not the distribution of estimated regression residuals allows a successful estimation of technical efficiency. The regression equation employing value added as the dependent variable gives a greater number of "successful" industries than the one using gross output. The correlation among estimates of the different measures of efficiency appears to be high, while the estimates of efficiency based on different regression equations seem almost uncorrelated. Thus, in the subsequent analysis of the determinants of interindustry variations in technical efficiency, the choice of the regression equation in the previous stage will affect the outcome significantly.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.4
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• pp.42-51
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• 2020

This study was performed to support the 6th forest basic planning by Korea Forest Service as predicting the change of forestland area by the transition of land use type in the future over 35 years in South Korea. It is very important to analyze upcoming forestland area change for future forest planning because forestland plays a basic role to predict forest resources change for afforestation, production and management in the future. Therefore, the transitional interaction between land use types in future of South Korea was predicted in this study using econometrical models based on past trend data of land use type and related variables. The econometrical model based on maximum discounted profits theory for land use type determination was used to estimate total quantitative change by forestland, agricultural land and urban area at national scale using explanatory variables such as forestry value added, agricultural income and population during over 46 years. In result, it was analyzed that forestland area would decrease continuously at approximately 29,000 ha by 2027 while urban area increases in South Korea. However, it was predicted that the forestland area would be started to increase gradually at 170,000 ha by 2050 because urban area was reduced according to population decrement from 2032 in South Korea. We could find out that the increment of forestland would be attributed to social problems such as urban hollowing and localities extinction phenomenon by steep decrement of population from 2032. The decrement and increment of forestland by unbalanced population immigration to major cities and migration to localities might cause many social and economic problems against national sustainable development, so that future strategies and policies for forestland should be established considering such future change trends of land use type for balanced development and reasonable forestland use and conservation.

• 한국노년학
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• v.39 no.4
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• pp.663-677
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• 2019

This study was performed to identify the relationship and effects of nursing work environment and role conflict on job embeddedness among nurses working in long-term care hospitals. The data were collected from 200 nurses working in 10 long-term care hospitals from G - province from July to August 2018. Structured questionnaires assessing general characteristics and three major variables were distributed to the study participants and final 190 data set were analyzed using SPSS ver 25.0 program. Study results were as follows; mean score of job embeddedness was 2.98±0.46 out of 5 and the score of sub-domains were in order of fit, links, and sacrifice. The average score of the nursing work environment was 3.14 ± 0.42 and the leadership was the highest sub-domain followed by the working system, the relationship with peers, and the support of the institution. Overall role conflicts score was 3.43 ± 0.51, and environmental disorder, role ambiguity, lack of ability, lack of cooperation were reported in order as sub-domains. Job embeddedness of the study participants showed a statistically significant positive correlation with the nursing work environment and negative correlation with the role conflict. Factors affecting job embeddedness were nursing work environment, age, and role conflict, and the explanatory power of the model was 50.4%. The findings suggest that the overall level of job embeddedness of nurses working in long-term care hospitals is below middle level and efforts to improve job embeddedness through strategies related to nursing work environment and role conflict in organizational level. In addition, the relationship between age and job embeddedness needs to be studied further.

• Journal of the Korean Society of Child Welfare
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• no.56
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• pp.133-164
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• 2016

This study investigated the effect of housing poverty in childhood on adolescents' subjective well-being. Specifically, this study examined whether the major factors that have been known to affect adolescents' well-being (i.e., family relationships, peer relationships, school adjustment etc.) mediated the relationship between housing poverty and adolescents' well-being. And then this study aimed to present an empirical evidence for establishing policies against housing poverty in order to enhance adolescent's subjective happiness. Data were derived from the $1^{st}$, $4^{th}$, and $7^{th}$ surveys of the Korea Welfare Panel Study(KOWEPS), and the sample included. 512 high school children in the $7^{th}$ survey. This study utilized structural equation modeling. Housing poverty was measured by the sub-minimum standard housing condition and the household's burden of housing expenditure. Family relationship, as a mediator, was measured by parental involvement in education, parental monitoring, and family conflicts. Another mediator, school adjustment was measured by school environment and school bonding, and the last mediator, peer relationship was measured by friend attachment and peer attachment. The results showed that housing poverty had significant negative effects on the adolescents' subjective well-being. The sub-minimum standard housing condition with inadequate size and facilities negatively affected adolescents' relationships with family directly and subjective well-being indirectly. In addition, the negative family relationships due to the sub-minimum standard housing condition negatively affected adolescents' subjective well-being through school adjustment and peer relationships. The greater the proportion of income a household spends on housing expenditure, the less likely for adolescents to report positive well-being. The sub-minimum standard housing condition had indirect effects through family relationships, whereas the household's housing expenditure directly affected adolescents' subjective well-being. This study suggested the necessity of interventions to alleviate housing poverty for adolescents' families and lays the groundwork for housing poverty policies in Korea.