• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.3
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• pp.61-68
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• 2018

As construction projects become larger, higher and more complex, efficient use of information is increasingly more important. As a result, there is a growing demand to apply BIM data obtained in the design stage to the construction stage. In this study, we propose a BIM-based construction schedule management system in order to promote introduction and application of BIM in the construction stage. Specifically, we provided how to build BIM database to be used for construction schedule management, and proposed how to obtain progress information and enter information based on analysis of progress schedule. We also provided a system of classifying construction works for more systematic use of BIM database, a process of using BIM database in construction projects, and a step-by-step guideline on how to establish the system. The proposed construction schedule management system provides information on particular construction schedule, as well as information and progress chart on delayed parts of the work so that a change in schedule can be managed. Additionally, by linking system database with the BIM model, construction progress can be checked in 3D simulation and a delay in construction schedule can be managed. As a result, using BIM at construction sites contributes to improving project productivity.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.218-223
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• 2009

During the process of excavation for substructures of buildings, precise and constant measurements of retaining wall displacement is crucial for construction to be complete and safe. Currently an inclinometer is used to measure displacement around the perimeter of an excavation site. The existing inclinometer system requires an instrument to be placed inside pre-bored holes for each measurement with an typical interval of two weeks. This makes it difficult to obtain continuous displacement data, especially during a critical time such as rainy season in summer. Also, the existing inclinometer is placed at certain distance away from the retaining wall system itself. Thus, exact measurement of retaining wall movement is compromised because of the distance between the retaining wall and the inclinometer. This paper presents the development of wireless inclinometer system for the displacement measurement of retaining walls by being attached directly to the retaining wall. The result of the application of the developed systems are provided with advanced ubiquitous sensor network (USN) system features. The USN technique incorporated into the system enables users to monitor movement data from wherever possible and convenient such as construction manager's office on site or any other places connected through internet. The research work presented in this paper will provide a basis to save construction time and cost by preventing safe-related unexpected delay of construction due to the failure or collapse of retaining walls.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.983-989
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• 2009

This study aims to systematically identify direct and indirect factors that influence labor productivity and to build a model that mathematically quantifies them so as to efficiently manage and increase labor productivity in the construction work. This study was performed based on the productivity model for workers in reinforced concrete construction projects, because it aims to establish a general construction labor productivity model that reflects many factors that influence labor productivity. Using statistical analysis, we found that the components that significantly influence productivity were the worker component, the work characteristic component, the work technique component, the work management component, the equipment & materials component, and the work guide component, while the work delay components did not significantly influence productivity. In addition, a priority analysis was performed based on the components that showed statistically significant effects. The results of the analysis indicated that the influence of work management component and the work technique component is more than that of the worker component and the work characteristic component. The construction labor productivity model that was formulated in this study could be used for the determining the standard productivity during the initial planning stage, so the best strategy for increasing labor productivity could be formulated.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.48-49
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• 2020

Recently the diversification of construction market and the continuous reduction of construction amount are raising the need of alternative delivery method in the construction industry. The foreign advanced companies actively adopted the CM at Risk delivery method where they perform the service of agent CM in the design phase, and agree GMP(Guaranteed Maximum Price) with the client at the time of 50~80% completion of design. Even in Korea they began to apply that method to pilot projects. In CM at Risk, through the early participation of builder, the level of design completion can be improved and the change order and construction period delay can be minimized. On the other hand, GMP is usually calculated when the design is about 80% complete, so there is uncertainty in the construction cost. Therefore, in this research, the increased amounts of construction cost are analyzed in a number of public construction projects, and GMP calculation process is proposed using the analysis results and CBR(Case-Based Reasoning) technique to reduce the construction cost increase in the construction phase.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.639-640
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• 2015

Traditional construction planning based on historical data and heuristic adjustment can no longer incorporate all the operational details and guarantee the expected performance. The variation between the expected and the actual production leads to cost overruns or delay. Although predicting reliable productivity on construction site is getting more important, the difficulty of this increases. In this regard, this paper suggested to develop BIM-integrated simulation framework. This framework could predict productivity dynamics by considering factors affecting on construction productivity at operational phase. We developed the following processes; 1) enabling a BIM model to produce input data for simulation; 2) developing the construction operation simulation; 3) running simulation using BIM data and obtaining productivity results. The BIM-integrated simulation framework was tested with structural steel erection model because steel erection work is one of the most critical process influencing on the whole construction budget and duration. We could improve to predict more dynamic productivity from this framework, and this reliable productivity helps construction managers to optimize resource allocation, increase schedule reliability, save storage cost, and reduce material loss.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.627-628
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• 2015

Construction defect which can causes economic damage such as schedule delay, cost overrun is a considerably important factor in construction industry. In general, a construction defect features a difficulty to find out causes precisely because it occurs when several interrelated causes combine. Yet, studies have tried to understand the interrelationships between factors are limited. In addition, despite of a tremendous amount of construction data, it's not still enough to analyze them, but tends to depend on experience or know-how of practitioners. Thus, it is necessary to identify underlying causes in influential factors by utilizing related data. This paper analyses Interrelationships between causal factors using Association Rule Mining to discover root causes of construction defects. Confidence and Lift that can be used for presenting the interrelationships of the causes were extracted from 1241 cases in 30 projects in Korea. It is expected that this paper allows the construction managers to discover key factors and make right decisions to reduce occurrence of construction defects. Furthermore, analysis of interrelationships can improve understanding of structural patterns of construction defects.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.444-450
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• 2013

Public private partnership (PPP) procurement was introduced into Singapore in 2003, and 10 PPP projects was successfully completed and have been in operation. The objective of this study is to identify the critical risk factors and risk allocation preferences for PPP projects in Singapore. To achieve this objective, a comprehensive literature review was carried out and 42 risks were identified and grouped into three meta levels, i.e. macro, meso and micro levels. The questionnaire survey produced 48 completed questionnaires from 48 different contractors. The survey results indicated that 23 risk factors had significantly high criticalities and that four macro-level risks, four meso-level risks and two micro-level risks were among the top 10 risk ranking. "Lack of support from government", "availability of finance" and "construction time delay" were perceived as the top three critical risks. Also, the result implied that micro-level risks had a higher criticality mean score than macro-level and meso-level risks. The findings of this study help both public and private sectors to better understand the risks and their allocation in PPP projects, providing valuable information for organizations that intend to participate in PPP projects in Singapore.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1154-1163
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• 2008

DAS and SCADA system are main systems, which operate and manage the power system by using computer and communication technology. But DAS and SCADA have been operated independently in Korea, so there was some time delay in the fault handling and live-line work. To improve that problems, studies on the interface between DAS and SCADA have been needed. From November 2005 to December 2007, the pilot project has been performed in KEPCO's branch offices, as a result, direct method will be applied widely all over the country until 2010 because the operation information of substation users want can be transmitted fast and it is possible to control 43RC directly although the expense for direct method is about 1.3 times larger than that for web method. To improve problems revealed during the pilot project, substation object to object communication method is proposed and interface database automatic generation and interface system diagnosis and logging functions are developed. Interface data point and communication data type are defined, substation single line diagram automatic generation or manual editing function, SCADA monitoring and controlling function, log data managing function are developed in SCADA HMI program. It is expecting to reduce the average time for each outage about 33% and to improve the reliability, efficiency of operation, execution of DAS from automatic load transfer under a fault, and to contribute to export project.

• Korean Journal of Construction Engineering and Management
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• v.16 no.5
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• pp.114-122
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• 2015

Real estate development requires significant amount of capital investment. The project duration has been increased according to its enlarged size. For this reason, cost overrun and time delay are important risk factors that should be managed properly. As a method to hedge the risk, varoius real option methods have been presented. However, conventional project value assesment methods such as NPV(Net Present Value) have weakness to support decision making by reflecting dynamic situations in terms of variation of cost and time. Furthermore, the decision making process is serious of actions rather than discrete event. The purpose of this paper is to present a multiple real option valuation method to overcome the deterministic aspect of real option presented in previous research and practice. The method is developed as following: firstly, to select the model that can be applied in the real estate development project through a survey from previous literature on real options analysis; secondly, to apply data from office development case in order to verify the model by applying conventional real option and multiple real option valuation. According to analysis result, multiple real option provides enhanced values comparing to NPV and single real option.

• Journal of Korean Philosophical Society
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• v.116
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• pp.155-180
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• 2010

The three means of listening, reflection and meditation (${\acute{s}}raava{\d{n}}a$, manana and $nididhy{\bar{a}}sana$) which are central devices of practice in $Ved{\bar{a}}nta$ philosophy should be understood not as a continuative step but as a methodological extension on condition of having one and the same purpose. In other words, the three means should be interpreted in a listening-oriented manner, in which the process has to be methodologically extended to reflection and meditation only when the direct knowledge on the reality is not gained in listening. This kind of interpretation can be more justified by displaying significant characteristics of Indian philosophy implied in the three means. It can be easily said that $Ved{\bar{a}}nta$ belonging to the liberation-centric tradition is a project of 'regaining essential self' through which the self becomes essential self by knowing that self. In this case the listening-oriented interpretation coincides with the basic teachings of $Ved{\bar{a}}nta$, since listening alone can be a sufficient means for obtaining knowledge of the original self. Further, as the project of 'regaining essential self' is carried out by the three means, these can be called a sort of 'event' that is carried out according to the scenario of $Ved{\bar{a}}ntic$ metaphysics. In this case listening is a course of comprehending the scenario of event participated by oneself, and that participant can accomplish the project by way of listening the scenario alone judged as somewhat more effective for liberation. However, in the later $Ved{\bar{a}}nta$ there arises a meditation-oriented interpretation of which three means are regarded not as a methodological extension but as a continuative step, because of the emphasis on meditation under the lasting influence of other philosophical systems. This is a result of epistemic desire that tries to convert what is heard to what is specially perceived or what is given to what is accepted. It may be said that this interpretation emphasizing the phased transition from the indirect to the direct of knowledge is an attempt to rationalize the repetitive delay of event as the actual failure of project. Furthermore, an assertion of the later $Ved{\bar{a}}nta$ which refers the fourth means called $sam{\bar{a}}dhi$ is based on the logic that the self-realization is possible apart from and outside the text, and accordingly it is incompatible with an assertion of the early $Ved{\bar{a}}nta$ that the self-realization is a reproduction as it is of the scenario guided by the absolute text. After all, the standard interpretation on the three means in $Ved{\bar{a}}nta$ have to be the listening-oriented, but not be the meditation-oriented or the $sam{\bar{a}}dhi$-oriented.