• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.52-53
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• 2017

Through the case study, we surveyed an applicability of digital fabrication in irregular-shaped building construction project. By digital fabrication, we mean is a precision manufacturing method has been used in aircraft, ship and car manufacturing industry. We collected construction-completed "LotteWorld Tower Podium" project data and analyzed its process in terms of construction quality andduration. The result shows that digital fabrication is considered a competitive technology that enabled to complete the project in seven months within 3mm surface curvature threshold. The digitalfabrication is expected to apply on a number of irregular-shaped building construction project.

• Journal of the Korean Institute of Landscape Architecture
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• v.24 no.4
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• pp.96-111
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• 1997

This study was carried out to identify users' choice behavior of theme parks. overland. Lotte World, Seoul Land, Dreamland and Children's Grand Park were selected as study areas. Both multinomial logic model(MNL), nested logic model(NMNL) and joint logit model wet$.$e test using a choice-based sample collected on study areas. Hausman-McFadden test showed that the MNL is not appropriate because the IIA assumption is violated. To avoid the problematic IIA assumption, the NMNL was tested. It splits similar alternatives into groups and nests separate decisions into hierarchical order to avoid the IIA assumption. Cluster analysis and discriminant analysis were conducted to find applicable nest structures. The inclusive value coefficient was 0.7788. It meant that sufficient condition of this model is met and users' choice behavior can be better understood by NMNL than MNL. The $\rho$2 value and accuracy of prediction of this model were 0.402 and 46.33% , respectively. Several comments were suggested to make the NMNL to be more reliable for future research on users' choice behavior of theme park.

• The Safety technology
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• no.174
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• pp.14-16
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• 2012

서울 잠실에 건설업계의 시선이 집중되고 있다 그 이유는 바로 롯데건설이 시공하고 있는 '롯데월드타워' 때문이다 지하 6층~지상 123층, 높이 555m 규모로 지어질 롯데월드타워는 국내 최고의 마천루 자리를 예약해 놓은 상태다. 전 세계적으로도 아랍에미리트의 부르즈칼리파(163층, 828m), 중국 상하이타워(124층, 632m)에 이어 3번째로 높다. 면적도 거대하긴 마찬가지다. 대지 면적이 8만$7182m^2$며, 연면적은 78만$2497m^2$에 달한다. 이 어마어마한 건물에는 전망대와 최고급 호텔 오피스텔, 사무공간 등이 들어선다. 또 연계된 저층부에는 명품 백화점, 패션 전문관, 스포츠 레저 시설 등이 입점할 예정이다. 실로 롯데월드, 올림픽공원 등 주변 관광자원과 연계된 국내 최대 관광클러스터의 등장이 임박한 것이다. 때문에 이곳 현장 임직원들의 자부심은 남다르다. 빈틈없는 안전관리로 역사에 기록될 작품을 만들겠다는 의지를 불태우고 있는 것이다. 안전으로 우리나라를 넘어 동북아시아의 랜드마크를 만들어가고 있는 이곳 현장을 찾아가 봤다.

• Journal of Korean Society of Steel Construction
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• v.26 no.4
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• pp.299-309
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• 2014

HSA800 is a new high strength steel (HSS) plate for building structures developed by POSCO and RIST in 2011. It has upper and lower bounds for yield ($F_y$) and tensile ($F_u$) strength as of 650-770MPa and 800-950MPa, respectively, with yield ratio ($F_y/F_u$) limit as of 0.85 which make steel quality more reliable and enhance the seismic resistance of structures. As made by TMCP, it has a good weldability without increasing carbon percentage. The objective of this study is to provide alternative design of mega-structural members of the Lotte World Tower (555m, 123 story), a first super-tall building in Korea, using HSS considering structural safety, constructability, and cost-effectiveness. Steel outrigger trusses, belt-trusses and steel exterior columns were selected and analyzed to evaluate the structural performance between original and alternative designs using HSS. The results show that HSS can be applied to the members which do not affect lateral stiffness of a building and, in this study, approximately 1100tons of steel were saved. It implies that HSS can save overall construction costs - manufacturing, delivery, and erection costs - by reducing mega structural member size. HSA800 was very first applied to the Lotte World Tower based on the results of this study.

• Journal of the Korean Regional Science Association
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• v.37 no.2
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• pp.17-33
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• 2021

This study empirically analyzes the effect of the spread of COVID-19 and the implementation of social distancing on the number of park users. To this end, we analyzed the time series data on the number of users and the COVID-19 outbreak at Olympic Park, a large-scale comprehensive urban park located in Songpa-gu, Seoul, and four neighborhood parks in the same municipality. And this was compared with the effect on the change in the number of users around Jamsil Lotte World, a representative indoor complex leisure space in Seoul. The analysis results are as follows: First, in small neighborhood parks located in residential areas, the number of users increased by 3 to 6% on average due to the implementation of the social distancing measures and the increase in the number of confirmed COVID-19 cases. In particular, it was found that changes in park use were sensitive to the increase in the intensity of social distancing. On the other hand, the number of users around Jamsil Lotte World decreased by 38% on average, and in the case of Olympic Park, the number of users decreased by 1.9% on average due to the spread of COVID-19. Considering that the number of the vehicle users representing remote users of Olympic Park has decreased by 23% on average, it is estimated that there is little change in the number of users in the surrounding areas. This suggests that urban parks, especially neighborhood parks in residential areas, play a role as a major refuge and leisure space for urban people in the event of a pandemic disaster such as COVID-19, and therefore need to be properly supplied and maintained.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.603-605
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• 1996

The SLIM used in the conveyance system has been generally developed the controller based on the slip frequency control and the VVVF method to obtain the quick response for the position control signal. This paper deals with the trust control of the SLIM by vector control with Bang-Bang condition. Also, the control system is composed of the PI controller for soft start of the SLIM and the q-axis current controller for correction in phase with Space Vector for reducing the harmonic pulsation in low speed. The processing for vector control and robust dynamic breaking control is carried out by MC80196KC micro processor and IGBT module. The proposed scheme is verified through the computer simulation and experiments for the 10KW SLIM.

• KIEAE Journal
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• v.2 no.3
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• pp.25-32
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• 2002

The demand for water in a city area has enormously increased due to the concentration of population and improvement of the living quality. In this reason, the water shortage and the pollution by city sewage seem to be inevitable. For saving city water and meeting the demands from the city, the wastewater recycling system can be used, which makes used water reusable by a certain purification process. In Korea, the application of a wastewater recycling system to the buildings has continuously been adopted since its first appearance at the Lotte World Complex in 1989. However, the system has not been in fashion because of its high cost and users' negative attitude against recycled water. A research based on literature review and a case study for a recycling water system was carried out and an estimation and evaluation model was proposed. The results from the present study suggest that the optimal size of the recycling water system should be designed within 30-40% of total water demand in a building. Also, it was found that economic benefits could be expected within the payback period of 5.3 years by securing the operation rate over 70%.

• Journal of the Korean Institute of Landscape Architecture
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• v.23 no.2
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• pp.1-16
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• 1995

This study was carried out to suggest method which can be used to improve competitive power of theme parks. The characteristics of Hybrid Conjoint Analysis were described and its usefulness for identification of specific types of service theme parks have to provide was tested "Lotte World, " "Seoul land," and "farmland" were selected as study areas, and .7 attributes with 3 levels were utilized for analyses. Master design with 81 profiles was constructed to meet the requirement of ′Compromise Plan 1,′and data was collected by in-personal interviews on the study areas. Respondents were grouped by cluster analysis, and their characteristics were analyzed by discriminant analysis. Then, part-worth of each attribute . was estimated by stagewise estimation model Calibrated model of each group did not show part-worths of attributes clearly because both main effects and 2-way interaction effects were included in the models. Therefore, calibrated models′ coefficients were used to calculate utilities of all possible combinations of attributes levels. The results showed that managers of theme parks have several options for providing a new service: the combination of attribute levels with the highest utility is they however, they can choose the other combinations with next highest utlities is they can not afford it. Several suggestions were described to cope with the problems when Hybrid Conjoint Analysis is applied to landscape architectural study.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.31 no.2
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• pp.100-107
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• 2023

This study intends to present the UAM pilot qualifications and training and education systems based on the roadmap of technology for K-UAM operation system, which is being promoted for commercialization in 2025. There are currently about 250 eVTOL manufactures around the world, and they are gearing up to produce a variety of UAM aircrafts. In Korea, 35 companies including Hyundai Motor company, Korean Air, Lotte and SKT are accelerating the development of UAM aircrafts. UAM is being developed as a public goods concept centered on public transportation and urban aviation rather than private transportation. Therefore, the UAM pilot qualification and education and training system should be suitable for operations in densely populated areas and complex urban enviroments. In other words, in order to ensure safe UAM operations, the competencies and qualifications of UAM pilots should be clearly established.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.2
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• pp.18-27
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• 2000

The importance of constraints has been one of major issues in recreation for prediction of choice behavior; however, traditional conjoint choice model did not consider the effects of these variables or fail to integrate them into choice model adequately. The purposes of this research are (a) to estimate the effects of constraints in theme park choice behavior by the constraints-induced conjoint choice model, and (b) to test additional explanatory power of the additional constraints in this suggested model against the more parsimonious traditional model. A leading polling agency was employed to select respondents. Both alternative generating and choice set generating fractional factorial design were conducted to meet the necessary and sufficient conditions for calibration of the constraints-induced conjoint choice model. Th alternative-specific model was calibrated. The log-likelihood ratio test revealed that suggested model was accepted in the favor of the traditional model, and the goodness-of-fit($\rho$$^2$) of suggested and traditional model was 0.48427 and 0.47950, respectively. There was no difference between traditional and suggested model in estimates of attribute levels of car and shuttle bus because alternatives were created to estimate the effects of constraints independently from mode related variables. Most parameters values of constraints had the expected sign and magnitude: the results reflected the characteristics of the theme parks, such as abundance of natural attractions and poor accessibility in Everland, location of major fun rides indoor in Lotte World, city park like characteristics of Dream Land, and traffic jams in Seoul. Instead of the multinomial logit model, the nested logit model is recommended for future researches because this model more reasonably reflects the real decision-making process in park choice. Development of new methodology too integrate this hierarchical decision-making into choice model is anticipated.