• Economic and Environmental Geology
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• v.51 no.1
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• pp.67-76
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• 2018

This study reviews three eco-friendly energy towns with hybrid thermal energy supply systems and borehole thermal energy storage (BTES) in Canada and Denmark. The district heating and cooling systems were designed by using multi-source energy for the higher efficiency and reliability as well as environment. ADEU (Alexandra District Energy Utility) located at the developing area in the city of Richmond, Canada was designed to supply district energy with the installation of 726 borehole heat exchangers (BHEs) and a backup boiler using natural gas. DLSC (Drake Landing Solar Community) located in the town of Okotoks, Canada is a district system to store solar thermal energy underground during the summer season by seasonal BTES with 144 BHEs. Brædstrup Solpark district heating system located in Denmark has been conducted energy supply from multiple energy sources of solar thermal, heat pump, boiler plants and seasonal BTES with 48 BHEs. These systems are designed based on social and economic benefits as well as nature-friendly living space according to the city based energy perspective. Each system has the energy center which distribute the stored thermal energy to each house for heating during the winter season. The BHE depth and ground thermal storage volume are designed by the heating and cooling load as well as the condition of ground water flow and thermophysical properties of the ground. These systems have been proved the reliance and economic benefits by providing consistent energy supply with competitive energy price for many years. In addition, the several expansions of the service area in ADEU and Brædstrup Solpark have been processed based on energy supply master plan. In order to implement this kind of project in our country, the regulation and policy support of government or related federal organization are required. As well as the government have to make a energy management agency associated with long-term supply energy plan.

• Korea journal of population studies
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• v.29 no.3
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• pp.111-137
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• 2006

The purpose of this study is to analyze how to change the fertility behavior at each parity after/before the economic crisis, and to find its significant determinants. The study assumes that because the socioeconomic changes have significant effects on the individual's fertility behavior, the individual's fertility behaviors and the determinants affecting fertility at each parity may change with economic crisis. Such assumption has been proven in this study. After the economic crisis, Korean fertility behavior at each parity has changed. The proportion of women having no child has increased. However, women who want to have a second child or a third one are more likely to do so within shorter period after marriage. The rectangularization of fertility has appeared after the economic crisis, because women married at later ages tends to finish their child bearing within the short period, especially before age 35. Based on the multiple variable analysis, the determinants affecting the fertility behavior have changed after the economic crisis. Interestingly, the men's safety job have the positive effects on the first childbearing while the women's safety careers have the negative effects on it, after the economic crisis. Before the economic crisis, both do not have significant effects on the first childbearing. This findings point out the limitation of women career favor policy, which purpose to raise the fertility rates by making good environments for women having children to work comfortably without the anxiety of child care.

• Proceedings of the KOR-KST Conference
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• 1995.12a
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• pp.45-73
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• 1995

The current paper presents a system dynamics model which can generate the land use anq transportation system performance simultaneously is proposed. The model system consists of 7 submodels (population, migration of population, household, job growth-employment-land availability, housing development, travel demand, and traffic congestion level), and each of them is designed based on the causality functions and feedback loop structure between a large number of physical, socio-economic, and policy variables. The important advantages of the system dynamics model are as follows. First, the model can address the complex interactions between land use and transportation system performance dynamically. Therefore, it can be an effective tool for evaluating the time-by-time effect of a policy over time horizons. Secondly, the system dynamics model is not relied on the assumption of equilibrium state of urban systems as in conventional models since it determines the state of model components directly through dynamic system simulation. Thirdly, the system dynamics model is very flexible in reflecting new features, such as a policy, a new phenomenon which has not existed in the past, a special event, or a useful concept from other methodology, since it consists of a lots of separated equations. In Chapter I, II, and III, overall approach and structure of the model system are discussed with causal-loop diagrams and major equations. In Chapter V _, the performance of the developed model is applied to the analysis of the impact of highway capacity expansion on land use for the area of Montgomery County, MD. The year-by-year impacts of highway capacity expansion on congestion level and land use are analyzed with some possible scenarios for the highway capacity expansion. This is a first comprehensive attempt to use dynamic system simulation modeling in simultaneous treatment of land use and transportation system interactions. The model structure is not very elaborate mainly due to the problem of the availability of behavioral data, but the model performance results indicate that the proposed approach can be a promising one in dealing comprehensively with complicated urban land use/transportation system.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.2
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• pp.19-30
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• 2012

Due to the fact that the social environment is improved and the urban development is stabilized, the demand of new construction of apartment becomes slowdown. Accordingly, there are many researches to lengthen the service life of the existing apartment through the remodeling and its importance is continuously rising. However, reliable design specifications and guidelines for the design of remodeling with partial demolition are not provided yet in Korea. Specially, in the apartment remodeling, slab collapse accidents take major portion in all accidents that reported by Korean Government. It is very important to prevent intial crack of slab because intial crack could cause severe accident like collapse of all structure in a short period of time. The purpose of this study is to develop structural guidelines that could guarantee the structural safety and serviceability of slab structure and could be adopted in Korean remodeling with partial demolition. There are mainly two components to determine structural behavior of slab structure. One is the shape of slab structure and the other is load which is resisted by the slab structure. In this study, the weight per unit volume of concrete debris and concrete strength are estimated through the analysis of previous researches to recognize the relationship between the shape of slab and load that loaded on the slab. Accordingly, approximately 300 pieces of floor plan are collected and analyzed. The finite element analysis is conducted using these analyzed and estimated results. From the finite element analysis results, the limited stacking height of debris is suggested and the stacking method is also discussed. In addition, to find the relationship between movement of demolition equipment and structural behavior of slab, the static and dynamic loading tests are conducted. From the results of loading tests, the impact factor which will be considered in the remodeling design could be estimated.

• Journal of Korean Home Economics Education Association
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• v.20 no.3
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• pp.145-161
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• 2008

The purpose of this paper is to find out the needs of housing contents in highschool Home Economics among students. The 105 housing contents and topics were chosen from the 3 textbooks and related references. The number of 516 questionnaire from 8 areas were used to analyze. Analyses indicated that respondents were more likely to favor Home Economics subject and one out of five wanted to select it. Average needs of the housing contents was above middle(3.4) and these was a little difference among 3 middle units in housing. The most needed unit was housing design. There was a more wide difference in 19 small units than in middle ones, ranged $3.00\sim3.91$. Individual contents showed the most variousness in needs from 2.89 to 4.30 in the middle unit of housing and environments, 3.00 to 4.01 in housing design, and 2.68 to 3.91 in housing management. The needs of additional contents were about the same as those textbook contents and it indicated that new textbook needs to adopt the newly demanded housing contents. Some of individual, family, and environmental characteristics were significantly related to the students needs. The higher positive attitude such as favor, interest, and selecting of the subject was related to the higher needs of housing contents. Residential areas and neighboring were also related to most of the needs of individual housing contents.

• Korean Journal of Heritage: History & Science
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• v.51 no.1
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• pp.80-99
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• 2018

In premodern society, the central spaces in local counties were known as Eupchi (邑治), in which Gwan-a (官衙). The Eupchi located in seaside counties were in Eupseong, whereas the Eupchi of inland counties only included a Gwan-a, and did not have a fortress. Yanggeun-gun (楊根郡) and Jipyeonghyeon (砥平縣), which currently form Yangpyeong-gun (楊平郡), were counties where only Gwan-a existed. At present, there are few traces of the Gwan-a in Yanggeun and Jipyeong. In addition, it is impossible to exactly verify the history, scale and location of these two Gwan-as. Therefore, this study attempts to make a rough estimation of the histories, scales and sites of these Gwan-a by analyzing the relevant literature and ancient maps that are scattered according to the principles of spatial organization of local Gwan-a. The Yanggeun and Jipyeong Gwan-a appear to have been built in the early Joseon period. There are three reasons for this assertion: First, in Yanggeun and Jipyeong, Suryeong (守令) were first officially appointed after the early Joseon period. Once Suryoeng were appointed to such counties, the Gwan-a in which they would serve could be established. Second, the Dongheon (東軒) in Yanggengun and the Gaeksa (客舍) in Jipyeonghyeon were rebuilt in 1703 (29th year of the reign of King Sukjong) and 1465 (11th year of the reign of King Sejo), respectively; thus; the Gwan-a must have existed since the early Joseon period.. Third, in Yanggeungun, the Hyanggyo (鄕校) had existed since the early Joseon period, as the Joseon government necessarily established the Hyanggyo in areas where Suryeong were established. The facilities of local Gwan-a in the Joseon period were largely divided into gonghae (公?), educational institutes, and alters. The gonghae was a facility in which the Suryeong and Gwanwon (官員) managed administrative, judicial and military affairs, and consisted of the A-sa (衙舍), Hyeongcheong (鄕廳), Jackcheong (作廳), Gaeksa (客舍), Gungwancheon (軍官廳), and so on. The education institute was called a Hyeonggyo, while alters included the Sajikdan (社稷壇), Seonghwansa (城隍祠) and Yeodan (?壇). Both the Yeongeun and Jipyeong Gwan-a also consisted of such facilities as A-sa, Hyangcheong, Jakcheong, Gaeksa, Gungwancheong, Hyeonggyo, Changgo, Sajikdan, Seonghwangsa, Yeodan, Saryeongcheong, Jiincheong and Gwannocheong. The present sites for both Gwan-as cannot be identified with any certitude. However, they can be roughly identified by connecting the related literatures, oral statements and relics with the principles of spatial organization of local Gwan-a in the Joseon period. ${\bullet}$ Address of the Yanggeun A-sa (Dongheon): the whole of # 15, Gwanmun 1-gil, Yangpyeong-eup (Yanggeun-ri 151) in front of Yanggeun Junior High School at present. ${\bullet}$ Address of Yanggeun Gaeksa: around the Yangpyeong police station at present. ${\bullet}$ Address of Jipyeong A-sa(Dongheon): the whole of Jipyeong-ri 248-250, Jipyeong-myeon at present. ${\bullet}$ Address of Jipyeong Gaeksa: the whole of Jipyeong-ri 238, Jipyeong-myeon at present.

• 한국노년학
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• v.36 no.3
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• pp.905-926
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• 2016

Although the concept of the elderly varies depending on scholars and laws, as consumption expenditure is deeply associated with income due to the nature of this study, 55 years old was set as the low limit standard for the elderly according to Prohibition of Discrimination on Age in Employment and Employment Promotion for the Aged Act and the elderly households were limited to single-elderly person household and an elderly couple family household for this study. It is considered consumption characteristics as a significant analysis subject in terms of social welfare because it could be understood as an expressed need which was a reflection of desire. Therefore, the present study aimed to investigate the consumption characteristics of the elderly households by stereotyping the consumption pattern of the elderly households, and find the determining factors for consumption patterns and thus contribute to the establishment of related policies through the expressed needs of the elderly households. K-means of cluster analysis was performed by putting the consumption expenditure of the elderly households to investigate inherent structural type of consumption pattern of the elderly households, which were the investigation subjects. As a result, four groups were stereotyped and named as below: 'health care-centered type', 'saving-centered type', 'livelihood-centered type', and 'food expenses-centered type' Binary Logistic Regression analysis was used to identify the factors that influence the decision of consumption pattern of the elderly households. The result of study showed that the elderly households faced all different needs and problems and thus there is a need for various approach plans to solve this situation. In particular, although the elderly have been viewed as economically poor people so far, the study showed that there were also kind of prepared households through saving. Overall, livelihoodcentered type accounted for the highest portion and, as a factor that influenced this, marital state and household income played an important role. Therefore, it is considered that more active efforts to increase the income of the elderly households are needed. In addition, age, owning of house and subjective health state were found to also have significant influence. Through these results of the study, the elderly's own improvement of awareness on health, presentation of overall standard for health state of the elderly, securement of the elderly's access to cultural life, and financial management coordination for improvement of quality of life, development and dissemination of jobs suitable for the elderly, and dissemination of communal life household, which is a cooperation residential type, were presented as institutional task in the conclusion.

• Journal of Intelligence and Information Systems
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• v.20 no.1
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• pp.35-48
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• 2014

According to the 2013 construction market outlook report, the liquidation of construction companies is expected to continue due to the ongoing residential construction recession. Bankruptcies of construction companies have a greater social impact compared to other industries. However, due to the different nature of the capital structure and debt-to-equity ratio, it is more difficult to forecast construction companies' bankruptcies than that of companies in other industries. The construction industry operates on greater leverage, with high debt-to-equity ratios, and project cash flow focused on the second half. The economic cycle greatly influences construction companies. Therefore, downturns tend to rapidly increase the bankruptcy rates of construction companies. High leverage, coupled with increased bankruptcy rates, could lead to greater burdens on banks providing loans to construction companies. Nevertheless, the bankruptcy prediction model concentrated mainly on financial institutions, with rare construction-specific studies. The bankruptcy prediction model based on corporate finance data has been studied for some time in various ways. However, the model is intended for all companies in general, and it may not be appropriate for forecasting bankruptcies of construction companies, who typically have high liquidity risks. The construction industry is capital-intensive, operates on long timelines with large-scale investment projects, and has comparatively longer payback periods than in other industries. With its unique capital structure, it can be difficult to apply a model used to judge the financial risk of companies in general to those in the construction industry. Diverse studies of bankruptcy forecasting models based on a company's financial statements have been conducted for many years. The subjects of the model, however, were general firms, and the models may not be proper for accurately forecasting companies with disproportionately large liquidity risks, such as construction companies. The construction industry is capital-intensive, requiring significant investments in long-term projects, therefore to realize returns from the investment. The unique capital structure means that the same criteria used for other industries cannot be applied to effectively evaluate financial risk for construction firms. Altman Z-score was first published in 1968, and is commonly used as a bankruptcy forecasting model. It forecasts the likelihood of a company going bankrupt by using a simple formula, classifying the results into three categories, and evaluating the corporate status as dangerous, moderate, or safe. When a company falls into the "dangerous" category, it has a high likelihood of bankruptcy within two years, while those in the "safe" category have a low likelihood of bankruptcy. For companies in the "moderate" category, it is difficult to forecast the risk. Many of the construction firm cases in this study fell in the "moderate" category, which made it difficult to forecast their risk. Along with the development of machine learning using computers, recent studies of corporate bankruptcy forecasting have used this technology. Pattern recognition, a representative application area in machine learning, is applied to forecasting corporate bankruptcy, with patterns analyzed based on a company's financial information, and then judged as to whether the pattern belongs to the bankruptcy risk group or the safe group. The representative machine learning models previously used in bankruptcy forecasting are Artificial Neural Networks, Adaptive Boosting (AdaBoost) and, the Support Vector Machine (SVM). There are also many hybrid studies combining these models. Existing studies using the traditional Z-Score technique or bankruptcy prediction using machine learning focus on companies in non-specific industries. Therefore, the industry-specific characteristics of companies are not considered. In this paper, we confirm that adaptive boosting (AdaBoost) is the most appropriate forecasting model for construction companies by based on company size. We classified construction companies into three groups - large, medium, and small based on the company's capital. We analyzed the predictive ability of AdaBoost for each group of companies. The experimental results showed that AdaBoost has more predictive ability than the other models, especially for the group of large companies with capital of more than 50 billion won.

• Journal of the Korean association of regional geographers
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• v.6 no.2
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• pp.1-19
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• 2000

This study is to investigate and analyze regional patterns of aging in Taejeon Metropolitan city-the overpopulated area of Choong-Cheong Province-by cohort analysis method. According to the population structure transition caused by rapid social and economic changes, Korea has made a rapid progress in population aging since 1970. This trend is so rapid that we should prepare for and cope with aging society. It is not only slow to cope with it in our society, but also there are few studies on population aging of the geographical field in Korea. The data of this study are the reports of Population and Housing Censuses in 1975 and 1985 and General Population and Housing Censuses with 10% sample survey in 1995 taken by National Statistical Office. The research method is to sample as the aging district the area with high aged population rate where the populations over 60 reside among total population during the years of 1975, 1985, 1995 and to sample the special districts of decreasing population where the population decreases very much and the special districts of increasing population in which the population increases greatly, presuming that the reason why aged population rate increases is that non-elderly population high in mobility moves out. It is then verified and ascertained whether it is true or not with cohort analysis method by age. Finally regional patterns in the city are found through the classification and modeling by type based on the aging district, the special districts of decreasing population, and the special districts of increasing population. The characteristics of the regional patterns show that there is social population transition and that non-elderly population moves out. The aging district with the high aged population rate is divided into high-level keeping-up type, relative falling type below the average of Taejeon city in aging progress, and relative rising type above the average of the city. This district can be found at both the central area of the city and the suburbs because Taejeon city has the characteristic of over-bounded city. But it cannot be found at the new built-up area with the in-migration of large population. The special districts of decreasing population where the population continues to decrease can be said to be the population doughnuts found at the CBD and its neighboring inner area. On the other hand, the special districts of increasing population where the population continues to increase are located at the new built-up area of the northern part in Taejeon city. The special districts of decreasing population are overlapping with the aging district and higher in aged population rate by the out-migration of non-elderly population. The special districts of increasing population are not overlapping with the aging district and lower in aged population rate by the in-migration of non-elderly population. To clarify the distribution map of the aging district, the special districts of decreasing and increasing population and the aging district are divided into four groups such as the special districts of decreasing population group-the same one as the aging district, the special districts of decreasing population group, the special districts of increasing population group, and the other district. With the cohort analysis method by age used to investigate the definite increase and decrease of aging population through population transition of each group, it is found that the progress of population aging is closely related to the social population fluctuation, especially that aged population rate is higher with the out-migration of non-elderly population. This is to explain each model of CBD, inner area, and the suburbs after modeling the aging district, the special districts of decreasing population, and the special districts of increasing population in Taejeon city. On the assumption that the city area is a concentric circle, it is possible to divide it into three areas such as CBD(A), the inner area(B), and the suburbs(C). The special districts of increasing and decreasing population in the city are divided into three districts-the special districts of decreasing population(a), the special districts of increasing population(b), and the others(c). The aging district of this city is divided into the aging district($\alpha$) and the others($\beta$). And then modeling these districts, it is probable to find regional patterns in the city. $Aa{\alpha}$ and $Ac{\beta}$ patterns are found in the CBD, in which $Aa{\alpha}$ is the special district of decreasing population and is higher in aged population rate because of aged population low in mobility staying behind and out-migration of non-elderly population. $Ba{\alpha}$, $Ba{\beta}$, $Bb{\beta}$, and $Bc{\beta}$ patterns are found in the inner area, in which neighboring area $Ba{\alpha}$ pattern is located. $Bb{\beta}$ pattern is located at the new developing area of newly built apartment complex. $Cb{\beta}$, $Cc{\alpha}$, and $Cc{\beta}$ patterns are found in the suburbs, among which $Cc{\alpha}$ pattern is highest in population aging. It is likely that the $Cc{\beta}$ under housing land readjustment on a large scale will be the $Cb{\beta}$ pattern. As analyzed above, marriage and out-migration of new family, non-elderly population, with house purchase are main factors in accelerating population aging in the central area of the city. Population aging is responsible for the great increase of aged population with longer life expectancy by the low death rate, the out-migration of non-elderly population, and the age group of new aged population in the suburbs. It is necessary to investigate and analyze the regional patterns of population aging at the time when population problems caused by aging as well as longer life expectancy are now on the increase. I hope that this will help the future study on population aging of the geographical field in Korea. As in the future population aging will be a major problem in our society, local autonomy should make a plan for the problem to the extent that population aging progresses by regional groups and inevitably prepare for it.