• Korean Journal of Construction Engineering and Management
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• v.25 no.2
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• pp.23-35
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• 2024

This study analyzed the correlation between each of the 12 influencing factors in FAR 16.04 and the decision-making process for construction contract types, using data from a total of 2,406 DoD Construction Acquisitions spanning from 2008 to 2022. The study considered 12 independent variables, grouped into 4 Characteristics with 3 factors each. Meanwhile, all other contract types were categorized into two types: Firm-Fixed-Price (FFP) and Cost-Reimbursement Contract (CRC), which served as the dependent variables. The findings revealed that FFP contracts significantly dominated in terms of acquisition volume. In line with prevailing beliefs, logistic data analysis and Analytical Hierarchy Process (AHP) analysis of Relative Weights from Experts' Survey demonstrated that independent variables like Uncertainty of the Scope of Work and Complexity found out to be increasing the likelihood of selecting CRC. The number of contractors in the market does indeed influence the possibilities of contract decision-making between CRC and FFP. Meanwhile, the p-values of the top 3 influencing factors on CRC from the AHP analysis-namely, Appropriateness of CAS, Project Urgency, and Cost Analysis-exceeded 0.05 in the binominal regression results, rendering it inconclusive whether they significantly influenced the construction contract type decision, particularly with respect to payment methods. This outcome partly results from the fact that a majority of respondents possessed specific experiences related to the USFK relocation project. Furthermore, influencing factors in construction projects behave differently than common beliefs suggest. As a result, it is imperative to consider the 12 influencing factors categorized into 4 Characteristics areas before establishing acquisition strategies for targeted construction projects.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.981-989
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• 2010

In this study, we introduce a new architecture of fuzzy inference system. In the fuzzy inference system, we use Fuzzy C-Means clustering algorithm to form the premise part of the rules. The membership functions standing in the premise part of fuzzy rules do not assume any explicit functional forms, but for any input the resulting activation levels of such radial basis functions directly depend upon the distance between data points by means of the Fuzzy C-Means clustering. As the consequent part of fuzzy rules of the fuzzy inference system (being the local model representing input output relation in the corresponding sub-space), four types of polynomial are considered, namely constant, linear, quadratic and modified quadratic. This offers a significant level of design flexibility as each rule could come with a different type of the local model in its consequence. Either the Least Square Estimator (LSE) or the weighted Least Square Estimator (WLSE)-based learning is exploited to estimate the coefficients of the consequent polynomial of fuzzy rules. In fuzzy modeling, complexity and interpretability (or simplicity) as well as accuracy of the obtained model are essential design criteria. The performance of the fuzzy inference system is directly affected by some parameters such as e.g., the fuzzification coefficient used in the FCM, the number of rules(clusters) and the order of polynomial in the consequent part of the rules. Accordingly we can obtain preferred model structure through an adjustment of such parameters of the fuzzy inference system. Moreover the comparative experimental study between WLSE and LSE is analyzed according to the change of the number of clusters(rules) as well as polynomial type. The superiority of the proposed model is illustrated and also demonstrated with the use of Automobile Miles per Gallon(MPG), Boston housing called Machine Learning dataset, and Mackey-glass time series dataset.

• Journal of the Korean Wood Science and Technology
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• v.47 no.3
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• pp.290-298
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• 2019

The sound absorption coefficient and transmission loss of several types of rice hull mats with varying apparent densities and thicknesses are estimated in this paper using the transfer function and matrix methods, respectively, to evaluate the possibility of using rice hull as an acoustic construction material. The mean sound absorption rates of 10-cm-thick rice hull mats with target densities of $0.10g/cm^3$, $0.12g/cm^3$, and $0.14g/cm^3$ were 0.91, 0.92, and 0.95, respectively, while those of the 1-cm-thick plywood attached to the back of the rice hulls were 0.90, 0.92, and 0.92, respectively. The means of the sound transmission loss of the 10 cm-thick rice hull mats with the target densities of $0.10g/cm^3$, $0.12g/cm^3$, and $0.14g/cm^3$ were 7.66 dB, 10.49 dB, and 14.14 dB, respectively, while those of the 1 cm-thick plywood attached to the back of the rice hulls were 33.34 dB, 36.72 dB, and 38.95 dB, respectively. In conclusion, a rice hull mat could be used as acoustic construction materials because of its high sound absorption coefficient and sound transmission loss.

• Korea Journal of Hospital Management
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• v.18 no.2
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• pp.15-32
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• 2013

Few public health researchers have paid research attention to the location of medical institutions in Korea. Previous studies were published in geography journals, and relied on limited data in terms of geographic regions and the type of medical institutions. This study utilized nationwide data covering 8 types of medical institutions. We obtained data from Health Insurance Review and Assessment Service and National Population and Housing Census. The correlation coefficients of resident, daytime, university-graduate population, and the population of different age groups (fewer than 15, 15~64, 65 or more) were compared to understand their relative association with the location of medical institutions. Medical clinic, dental clinic, oriental medical clinic, and pharmacy, all of which are almost completely operated by private sector, showed strong positive correlation with population. Hospital-level medical institutions, which are operated by both public and private sector, had moderate positive correlation. Daytime population and university-graduate population, rather than resident population, were more correlated with the location of medical clinics. The correlation coefficients of the population of 15~64 age group and the location of medical institutions were greater than that of other age groups. The results showed that daytime and university-graduate population are more important than resident population to explain the location of medicalrelated facilities. The results also suggests that the population of age groups (especially, 15~64) might be one of important influence factors in the location of medical institutions.

• Journal of architectural history
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• v.15 no.3
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• pp.99-118
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• 2006

We have focused on the building appearance according to the change of conservation policy and urban fabric in Bukchon, Seoul. The Urban Hanok, urban traditional housing type, had been evolved in modern contort from 1920's to 1960's, that is to say, many buildings(Urban Hanok) in Bukchon area has built up with a lot and road at the same time. But the change of conservation policy has an effect on the urban fabric and building(wooden structure, RC and brick building). Thus many types of building in Bukchon has undergone a various change. The purpose of this paper is to define a change factor of Bukchon buildings. Thus we need to pay attention to policy and urban fabric. We reached the result as follows. First, the change of architecture regulations according to the several policies(an aesthetic area, an altitude area for sky line restriction and so on) brought into building deformation and eventually the historic scenery of Bukchon has been spoiled. Second, the change of policy had an effect on the change of roads and lots. Buildings on a widen road and a united lot was built newly. But new buildings built up with a concrete or brick structure was not in harmony with the historic scenery of Bukchon area. Third, a development method of a large lot with lack prudence(disregarded a scale and size of lot) did damage to Urban hanok and urban fabric. With the understanding on the relationship of buildings, a urban fabric and a policy in Bukchon, we can define the identity and correspond with the urgent request for a the conservation of historic urban scenery In addition we can suggest the policy and the design guidelines for the reservation and rehabilitation for Bukchon, Seoul.

• Journal of the Korean Institute of Rural Architecture
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• v.13 no.3
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• pp.125-132
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• 2011

By this time the main tendency of studying traditional residential building was to find out and analyze the regional and spacial peculiarity. But that kind of study has been set limits in terms of including each building into one category and being researched by the viewpoint of an observers rather than a resident. Due to this kind of problem, the outcome of that study didn't obtain good results. This study, which has synthetically not been investigated until now, have put a little more deep interpretation on traditional residential building, by surveying Andong Kwon family's Yuhoedang-Chongga located 299 Musudong Daejon. The purpose of this study is to investigate the characteristic of construction in the architecture of Yuhoedang-Chongga of the Andong Kwon family, and to develop the viewpoint and analytic process of traditional construction. As the first step to study it efficiently, basic architectural investigation on Yuhoedang-Chongga has been carried out with an actual evidence, and the new viewpoint of traditional residential building has been developed by this survey such as collecting, arranging, analyzing and examining this positive proof. For example, from the house-picture book handed down from that family, the condition of then established was compared with the present state of it. And then this article examines the arrangement, floor-plan types, interior, structures and condition of location. The transition-history of this house was searched into, and the development process of this was examined. The related documents was synthetically analyzed, so the characteristics of this construction was grasped.

• Human Ecology Research
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• v.62 no.1
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• pp.15-32
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• 2024

The purpose of this study was to analyze the research trends and co-author networks of academic articles published in the Journal of the Korean Home Economics Association from 2010 to 2022. The network analysis was conducted using Excel and NetMiner 4.4, and the results were as follows. First, the number of published articles has been maintained at around 40 per year since 2019. By field, most articles were published in the field of child studies and family studies, followed by consumer studies, home management, clothing studies, home economics education, food and nutrition, and housing. The research methods were primarily quantitative (71.61%). Second, the most common keywords in the titles of the published articles were "influence" and "relationship", with "influence", "consumer", "mediating effect", "parent", and "control" identified as influential keywords. Third, the published articles were categorized into nine topics based on subject matter, while the number of topic types varied by year. Fourth, the total number of authors of the 627 articles was 712, with 1.92 authors per article, as well as the number of authors who published two or fewer articles accounted for 85.5% of the total. By institution, Yonsei University had the highest number of authors and the highest number of published articles, while Korea National Open University played a leading role in the network of co-authors by institution. This study is significant in providing basic data for the future development of the Korean Home Economics Association and the field of home economics.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.1
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• pp.35-42
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• 2011

The current study analyzed appropriateness of abandoned rice paddy wetlands as habitats for the Amphibia by assessing functions and value of abandoned rice paddy wetlands within land development districts as a habitat for living creatures and researching into the Amphibia living in the subject districts. For this purpose, the study designated abandoned rice paddy wetlands within Hwaseong A District and Pangyo B District under land development as subject lands. Those wetlands went through succession after abandonment of farming. Detailed study results are as follows. From classification of wetland types and an analysis of their characteristics, it was found that herbaceous plants such as smartweed communities, horsetail communities and reed communities, and woody plants such as pussy willow communities appeared in both districts. These abandoned rice paddy wetlands shows typical characteristics of palustrine wetlands. As a result of a vegetation structure research, it was observed that succession has been progressed for at least over 2~3 years. In assessment of wetland functions by item, it was found that they are developing into fine wetlands in terms of functions because they are ranked over Moderate Class except separate distance from streams. Also from a research into animals living in the abandoned rice paddy wetlands, it was found that main inhabitants are Rana nigromaculata,Rana dybowskii, Hyla japonica, Bufo bufo gargarizans, etc. It can be confirmed that the abandoned rice paddy wetlands are providing appropriate conditions as habitats to the Amphibia in a view that those species have life cycles of inhabitation (shores and wetlands) - egg-laying (rice paddy, puddles and swampy places) - hibernation (rice field banks and swampy places). From this point of view, it was found that abandoned rice paddy wetlands that developed because of abandonment of farming can be used as means to improve structure and functions of habitats.

• Journal of Families and Better Life
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• v.29 no.4
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• pp.125-145
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• 2011

The purposes of this study were to examine low-income households' financial statuses and the socio-economic characteristics of single-person and non-single person households according to the financial indexes used for evaluating financial security and growth status developed based on financial ratios. Using 2009 KLIPS(Korean Labor & Income Panel Survey) data collected by the Korean Labor Institute, the satisfaction levels from the indexes were analyzed and compared between the two household types. The results showed that 46.0% of single-person households were not satisfactory in terms of all financial growth indexes but were partially satisfactory in terms of all financial security indexes. These householders tended to be females and in the their 70s, who lived in Seoul or in a suburb of Seoul, Korea. They reported problems with a lack of financial growth possibilities. 47.0% of non-single person households were not satisfactory in terms of all financial growth indexes but were partially satisfactory in terms of all financial security indexes. These householders tended to be males in their 60s and 70s with no job who were living in Seoul or in a suburb of Seoul, Korea. They reported having low level of liquidity and high level of debt redemption. 42.6% of single-person households were not satisfactory in terms of both financial security and growth indexes partially. These householders tended to be females in their 20s or 70s who were living in rural areas. They reported problems related to an adverse balance between household income and expenditures and a large scale of debt. 43.1% of non-single households were not satisfactory in terms of both financial security and growth indexes partially. These householders tended to be males in their 60s or 70s and homeowners. They reported problem related to an adverse balance of household income and expenditures and high a level of housing expenditures and liquidity. The research findings have implication for policy makers considering financial support programs and welfare programs for low-income householders, considering the recent changes in households structures.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.184-192
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• 2011

In this study, we introduce a identification methodology for FCM-based fuzzy model. The two underlying design mechanisms of such networks involve Fuzzy C-Means (FCM) clustering method and Particle Swarm Optimization(PSO). The proposed algorithm is based on FCM clustering method for efficient processing of data and the optimization of model was carried out using PSO. The premise part of fuzzy rules does not construct as any fixed membership functions such as triangular, gaussian, ellipsoidal because we build up the premise part of fuzzy rules using FCM. As a result, the proposed model can lead to the compact architecture of network. In this study, as the consequence part of fuzzy rules, we are able to use four types of polynomials such as simplified, linear, quadratic, modified quadratic. In addition, a Weighted Least Square Estimation to estimate the coefficients of polynomials, which are the consequent parts of fuzzy model, can decouple each fuzzy rule from the other fuzzy rules. Therefore, a local learning capability and an interpretability of the proposed fuzzy model are improved. Also, the parameters of the proposed fuzzy model such as a fuzzification coefficient of FCM clustering, the number of clusters of FCM clustering, and the polynomial type of the consequent part of fuzzy rules are adjusted using PSO. The proposed model is illustrated with the use of Automobile Miles per Gallon(MPG) and Boston housing called Machine Learning dataset. A comparative analysis reveals that the proposed FCM-based fuzzy model exhibits higher accuracy and superb predictive capability in comparison to some previous models available in the literature.