• Korean Journal of Construction Engineering and Management
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• v.12 no.3
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• pp.121-130
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• 2011

Real option values of early termination payment for selected BTO PPI projects are studied using binomial models. Two cases of early termination payments are considered; an option with the condition of private participants' default, and an option without the condition. Values vary depending upon parameter values such as revenues, costs, discount rates, debt ratio, and volatility of revenues. For selected projects, the option values without the default condition are estimated as 1%~7% of total project costs, whereas the option values with the default condition are estimated as 0%~1.89% of total project cost. When actual revenues differ from the forecasted revenues, apparently the option values deviate from the values based upon the forecasted revenues. When actual revenues fall short of the forecasted revenues, the option values increase by a large amount whereas the option values decrease by a small amount in the opposite case. This implies that the option values can be quite bigger than the values based upon the forecasted revenue especially when the revenue forecast uncertainty is large. This study is expected to play an important role in improving the early termination payment option policy of the government in PPI projects in Korea.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.3
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• pp.247-252
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• 2008

Recently, the virtual construction system in which project participants efficiently share and control the information throughout the life-cycle of construction project using 3D object models is being developed all over the world. In this paper, a design of interface between 3D object model of structures and structural analysis system that is essential for the analysis and design of civil structures in the virtual space is treated. The relation parametric modeling technique that is needed to make the 3D object models and the construction method of product breakdown structure(PBS) that considers the several parameters for the structural analysis are presented. PBS is built so that it is possible to extract needed attribute information from 3D object model and to apply it to the structural analysis. Design methodology for interface program is proposed that several numerical values determined by the cooperative work same as structural analysis are delivered to 3D object models without additional work. An interface program between 3D object models and structural analysis system developed based on the proposed method would be effectively used to develop virtual construction system.

• Korean Journal of Construction Engineering and Management
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• v.14 no.3
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• pp.134-145
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• 2013

Road construction projects are parcelled into sub-sections which are then tendered to individual contractors for construction. The type of work and equipments used are similar for each sub-section. However, such equipment are not shared on a regular basis among the contractors and only partially performed in an informal and ad hoc manner. Consequently, road construction equipment suffer from low utilization and increased leasing costs. Lean construction and Program Management approaches stress the importance of collaboration among individual participants in a way that increases the collective cost savings of the entire project. This research attempts to apply such theories with the notion that under utilization of expensive equipment can be improved by formalizing a way to enable the sharing of equipment in large, public sponsored, multi-sectioned road construction projects. A system was developed consisting of a set of criteria and processes that enables automatic allocation of equipment to multiple sites on daily basis, in a way that minimizes equipment costs and improves their individual utility. The system was then applied in allocating three different types of equipment to an actual road construction project with four sub-sections for three months. A new metric, nDPR showed that utilization improved for all equipment and also equipment related costs were decreased by 4.45%. Results also showed that increased shared opportunities of equipment correspond to an increase in utilization and cost savings.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.147-153
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• 2021

The purpose of this study is to establish strategic suggestions for the direction of the drone-related business by Gyeonggi-do through a survey on the operation and actual conditions of the drone geospatial information service business experienced by Gyeonggi-do civil servants. For this purpose, as a result of surveying the demand survey of 219 people in charge of drone field work, it was analyzed by dividing it into four categories: technology-based operation support, business discovery and support, legal and institutional support, and education and public relations. As an improvement measure, technology-based operation support is to secure service operation efficiency by establishing a dedicated manpower and a dedicated organization and securing drone-related experts.The plan for improvement of project discovery and support is as follows. 1) The government proactively discovers prior research projects for project discovery and support; 2) Legal and institutional support requires support services for simplification of administration such as drone geospatial data shooting schedules and permits, 3) legal and institutional review on improving the scope and restrictions for using drone geospatial data. In the field of education and publicity, it is necessary to operate an education program on the overall operation of drones, and to conduct seminars for each field and use, and to seek activation methods through practical application guidelines for the application process and system. The limitation of this study is that the survey subjects are related to Gyeonggi-do, and in the future, survey analysis through a wide range of participants is required.

• Journal of Construction Engineering and Project Management
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• v.8 no.4
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• pp.1-24
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• 2018

In the last decade, the use of Building Information Modeling (BIM) as a new technology has been applied with traditional Computer-aided design implementations in an increasing number of architecture, engineering, and construction projects and applications. Its employment alongside construction management, can be a valuable tool in helping move these activities and projects forward in a more efficient and time-effective manner. The traditional stakeholders, i.e., Owner, A/E and the Contractor are involved in this BIM system that is used in almost every activity of construction projects, such as design, cost estimate and scheduling. This article extracts major features of the application of BIM from perspective of participating BIM components, along with the different phrases, and applies to them a logistic analysis using a fuzzy performance tree, quantifying these phrases to judge the effectiveness of the BIM techniques employed. That is to say, these fuzzy performance trees with fuzzy logic concepts can properly translate the linguistic rating into numeric expressions, and are thus employed in evaluating the influence of BIM applications as a mathematical process. The rotational fuzzy models are used to represent the membership functions of the performance values and their corresponding weights. Illustrations of the use of this fuzzy BIM performance tree are presented in the study for the uninitiated users. The results of these processes are an evaluation of BIM project performance as highly positive. The quantification of the performance ratings for the individual factors is a significant contributor to this assessment, capable of parsing vernacular language into numerical data for a more accurate and precise use in performance analysis. It is hoped that fuzzy performance trees and fuzzy set analysis can be used as a tool for the quality and risk analysis for other construction techniques in the future. Baldwin's rotational models are used to represent the membership functions of the fuzzy sets. Three scenarios are presented using fuzzy MEAN, AND and OR gates from the lowest to intermediate levels of the tree, and fuzzy SUM gate to relate the intermediate level to the top component of the tree, i.e., BIM application final performance. The use of fuzzy MEAN for lower levels and fuzzy SUM gates to reach the top level suggests the most realistic and accurate results. The methodology (fuzzy performance tree) described in this paper is appropriate to implement in today's construction industry when limited objective data is presented and it is heavily relied on experts' subjective judgment.

• Korean Journal of Construction Engineering and Management
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• v.23 no.1
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• pp.3-15
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• 2022

Daycare center is an important space for children's mental, physical and social development. Each space of daycare center should be designed and constructed considering interests of end-users such as children and teachers. However, insufficient related guidelines and standardized design and construction of daycare center to moderate potential risks of each space. This arises from the difference in perception of each space between end-users (head and sub teachers) and construction experts (designers and contractors). Therefore, research framework was developed for analyzing the factors of perception differences of each space in daycare center between these groups applied traditional and modified Importance-Performance Analysis (IPA). By comparing risk perception between end-users and experts in two methods, it can be support as construction guide for daycare center in the future and will help minimize conflicts in construction among stakeholders. Moreover, it was found that traditional IPA is comfortable to catch prior project perception of participants, and revised IPA is considered to judge outputs by identifying participant's importance based on the satisfaction of the project performance. Therefore, if IPAs are applied according to the characteristics of the circumstances, it is possible to analyze the perception difference between end-users and construction experts based on the context before and after the construction of the daycare center.

• Journal of Korean Elementary Science Education
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• v.43 no.2
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• pp.337-352
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• 2024

This study develops an informal science education program based on a creative design for the promotion of participation and action and explores the validity and effectiveness of the program. The program consists of three mini-projects, namely, The Martian: Surviving from the Mars, So Good to Have Seonjeongneung, and Designing a Sunshine Restaurant, with distinct topics focusing on the localization and contextualization of the region in which the program was implemented to encourage students' participation and action. The researchers selected three topics for each mini-project through discussions and revisions. The program is designed for 42 lessons across the three mini-projects and offers a presentation session in which students present their learnings from the program, constructed to facilitate personal contextualization. Participants included 15 elementary school students from Grades 5 and 6 who took surveys before and after the program. The pre-post surveys comprised two dimensions, 'Participation and Action' and 'Positive Experience about Science,' to examine the effectiveness of the program. At the end of the survey, we added a self-descriptive question that allows students to freely write down their feelings and thoughts. We checked the students' thoughts. The effectiveness of the program was illustrated by the largest increase in the "safe society" category, whereas there was little increase in other categories under the 'participation and Action' dimension in the Korean Science Education Standards. 'Science-related Self-concept' exhibited the largest increase, whereas the other categories displayed little increase from the 'Positive Experience about Science' dimension category.

• Korean Journal of Construction Engineering and Management
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• v.25 no.4
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• pp.24-33
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• 2024

Recently, as smart construction has become more active, construction companys are evaluating their smart construction capabilities in order to transform into smart construction companies. However, the revitalization of smart construction doesn't only apply to construction companies, the level of utilization of all participants, including owners, designers, construction project managers, and construction company, must be improved. Therefore, this study aims to present a model that evaluate the building information modeling (BIM) utilization level for measuring the BIM utilization level of construction management companies in executing construction project management. In this study, an AHP questionnaire survey targeting BIM practitioners to calculate the weight of each BIM utilization item and score it to construct evaluation model and evaluate it by applying it to construction management companies are conducted. As a result of the evaluation using model, there were differences between companies in the number of BIM users, and in the qualitative evaluation, it is mainly used for interference review, constructability review, and design change management. Therefore, in order to revitalize BIM, it is believed that it is necessary to strengthen BIM utilization ability through separate training for construction manager (CMr) and to present clear utilization standards and scope of work for BIM utilization in performing construction management tasks. Consequently, evaluating more construction management companies using the model presented in this study will result in the transition of CM companies to smart construction and revitalization of BIM adoption.

• Korea journal of population studies
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• v.19 no.1
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• pp.93-122
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• 1996

This is a study of the determinants of sexual, contraceptive, and abortion behavior among unmarried female adolescents and young adults, which has emerged as a growing and serious health problem in Korea. As part of a larger project, data were gathered in three export zones: Kuro (Seoul), Kumi (Kyngbuk) Masan Changwon (Kyongnam) ; and the study samples are regrouped into three categories: 1) factory workers, i.e. , the reference group serving as program participants, 2) entertainment workers, and 3) ob-gyn patients. This study indicates that entertainment workers are at highest risk of experiencing premarital sex, STDs, contraceptive failure, unwanted pregnancies, and induced abortion. Of them, 20 percent had STDs as a result of first sexual experience: and about seven tenths had two or more pregnancies due to the adoption of low-efficacy methods. The proportion of those who had ever been pregnant was 60 percent for the group as a whole: 36 percent for the program participants: 64 percent for the entertainment workers ; and 91 percent four the ob-gyn patients. These proportions are exactly the same for abortion in each group, which means that all pregnancies ended in induced abortion. Of the respondents who said that they were sexually active at the time of survey, abortions were very high: 1.6 for the program participants, 2.3 for the entertainment workers, and 1.9 for the ob-gyn patients. About 80 percent of the women had abortions during the first trimester, and two thirds of the first abortions took place between the ages of 20 and 23. About one fourth experienced post-abortion complication, which was highest among the program participants (39 percent). Sixty percent of those with complications visited a hospital or took medicine to treat the problem. Even after the experience of induced abortion, the use of contraception was very low, except among the entertainment workers, whose level of use reached 53 percent. The most obvious recommendation, arising from this research, is that 'good-quality' counselling and family planning services be established under the auspices of both national and local government, particularly targeted for the entertainment workers as well as the factory workers in various textile, electronic, manufacturing, and other industrial sectors. We believe that entertainment sectors should be restructured radically so that young women who work for amusement bars and other entertainment sectors obtain protection from the risk of having unwanted pregnancies, STDs, and induced abortion.

• Journal of the Korean School Mathematics Society
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• v.9 no.4
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• pp.575-595
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• 2006

In this paper, we investigated the effects of mathematics classes using play-action programs in the course of mathematics education of future elementary school teachers. This study was conducted with 43 junior university students who selected 'Play Mathematics' in 2006. All the participants in this course was divided 11 groups. Play-action mathematics programs was consisted of 12 themes. For example, there was tangram, somacube, hexamino, tessellation, geoboard etc. In the beginning of lessons, we investigated theses themes itself through plays, puzzles, games, and computer programs. And next time, we investigated the relationships between these themes and elementary mathematic textbooks(i.e. mathematical contents). In 14th and 15th lessons, all the groups took a project presentation lessons that included all things about play mathematics in all group categories. And they developed two themes of play mathematics in accordance with grades, contents, levels as course tasks. Through this study, three educational effects induced. First, future elementary school teachers have a deep understanding about play-action mathematics. They are interested in these play themes, and take part in these play mathematics programs of their own accord. And they realize that these play themes are related to elementary mathematics. Second, future elementary school teachers' attitude and mind about mathematical are improved after this course. Third, future elementary school teachers comprehend various instruction methods relating to play mathematics. Therefore, we suggest that future elementary school teachers need to have many opportunity to experience and develop a mathematics classes using play mathematics.