• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.50-56
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• 2022

Change Orders generally impact cost and schedule performance of highway projects. However, highway projects that do not have any change orders also face cost growth and schedule delays. This study seeks to determine the cost and schedule performance of Texas DOT projects by collecting project data for 120 highway projects completed between 2016 to 2020. For the study, we selected project data that has zero or negative change orders which were then grouped and analyzed based on their Project Types i.e., maintenance works; structural works; restoration and rehabilitation works; and safety works. The study found that performance of Maintenance and Safety type projects had less cost and schedule growth among the data analyzed. Statistical tests also found that even though the projects have no change orders, Rehabilitation and Restoration type projects experienced significant schedule growth compared to others. However, the data did not show any significant cost and schedule growth for the projects when statistical tests were performed on overall data. The study concluded that highway projects are experiencing schedule growth even though the projects had no change orders. Results from the study can help planners, engineers, and administrators to gain better insight on how different types of highway projects are performing in terms of cost and schedule and eventually derive appropriate solutions to minimize cost and schedule growth in such projects.

• 한국군사과학기술학회지
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• 제21권3호
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• pp.396-402
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• 2018

Earned Value Management(EVM) has been used to manage and forecast defense project schedule and cost over the last two decades in the world. However to support the lacking ability of schedule analysis in traditional EVM, earned schedule(ES) has been introduced as a tool to more accurately estimate schedule performance. This paper compares which method EVM or ES, provides more accurate schedule predictors in 32 Korean defense research and development projects. As a result of comparison, the ES method can predict the future schedule more reliably than the EVM method. We also analyze early warning function of schedule performance index considering project duration extension point. Through the analysis results, we confirm that both the EVM and the ES method lack the ability of the early warning in terms of the current schedule management criterion.

• 한국군사과학기술학회지
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• 제22권4호
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• pp.567-574
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• 2019

Traditional project progress method(PPM) has been used for Korean defense research and development project management for the last 20 years. However, it is difficult to intuitively understand the performance in terms of the project schedule, because the PPM does not provide the function of managing and forecasting project schedule. Therefore, this paper proposes new schedule managing and forecasting function for the PPM using earned schedule management concept. We verify the effectiveness of the proposed functions through several defense projects and prove that it is possible to reinforce the schedule management function of the PPM.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.527-531
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• 2015

With the mounting concerns over environmental issues, green construction is gaining a place in the global construction industry. However, rare research has been conducted to analyze green construction projects, especially in the aspect of project schedule performance. As a result, this study aims to investigate the degree of project delay in green building construction, analyze the factors affecting schedule delay of green building projects, and finally provide recommendations to improve schedule performance of green building project. To achieve the objectives, a comprehensive literature review was carried out, followed by a survey conducted with 30 companies that provided data from 220 traditional and 96 green building projects. The analysis of the responses identified that 15.9% of the traditional building projects were delayed while 32.3% of the green building projects were completed behind schedule. Furthermore, the amount of the delays in green building projects was an average of 4.8% of their planned schedule. The top 5 critical factors that can cause delay in green building projects were identified as: (1) speed of decision-making by clients; (2) speed of decision-making involving all project teams; (3) communication/coordination between key parties; (4) level of experience of consultants; and (5) difficulties in contractors' project financing. Lastly, a list of recommendations was introduced, aiming to reduce schedule delay in green building construction projects based on the observations. This study will serve as s a base for further research on the enhancement of green building project schedule performance.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2002년도 학술대회지
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• pp.456-459
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• 2002

오늘날 건설공사의 효율화를 위한 EVMS(Earned Value Management System)도입의 중요성을 인식하고 많은 연구가 발표되고 있다. 그러나 EVMS를 도입한 공정에 대한 경험부족과 국내 건설의 제도적${\cdot}$환경적 요인으로 인해서, 기술적인 분석이나 사례분석에 대한 관한 연구는 아직 미흡한 실정이다. 본 연구에서는 EVMS를 도입한 공정상에 성과지수(SPI : Schedule Performance Index, CPI : Cost Performance Index)를 산정하여, 여러 통계적 분석방법을 적용해서 프로젝트 관리상에 일정, 비용상의 추세(Trend) 및 문제의 원인을 분석${\cdot}$연구하고자 한다.

• 한국건축시공학회지
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• 제15권6호
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• pp.641-651
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• 2015

With its recent tourism boom, Vanuatu, a small country in the South Pacific, is experiencing an increasing demand for construction. However, it has been struggling with persistent schedule delays in their construction projects due to a variety of reasons. In an attempt to respond to this situation, this paper aims to identify the major causes of schedule delays in building construction in Pacific island countries, with a focus on Vanuatu. To collect data on the factors affecting schedule delays, face-to-face interviews were conducted. Based on these, seven major causes of schedule delays, as selected by the majority of the participants, were identified and discussed to provide perceptive insights for future improvement opportunities. This paper attempts to help contractors with limited resources better understand the major causes of schedule delay in Vanuatu and achieve better performance in building projects.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.412-418
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• 2013

With the increasing demand for public housing, the Singapore government decided to reduce the waiting time of future public housing owners, which requires these projects to be completed on time. As a result, this study aims to identify the frequent and impactful factors affecting schedule performance of public housing projects in Singapore. The survey conducted with 36 industry experts revealed that "site management", "coordination among various parties", "design changes by owner during construction", "availability of laborers on site", "availability of material", and "availability of staff to manage projects" were the six factors that should be emphasized to assure the schedule performance of public housing projects. In addition, there was statistically significant agreement between public housing projects and other building projects on both the frequency and impact ranks of the factors. The findings from this study will help practitioners involving public housing projects to take measures to assure the achievement of project schedule objectives.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권12호
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• pp.5401-5421
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• 2016

Both low-density parity-check (LDPC) codes and the multiple access technique of spatially coupling data transmission (SCDT) can be expressed in bipartite graphs. To improve the performance of iterative demodulation and decoding for SCDT, a novel joint sparse graph (JSG) with SCDT and LDPC codes is constructed. Based on the JSG, an approach for iterative joint demodulation and decoding by belief propagation (BP) is presented as an exploration of the flooding schedule, and based on BP, density evolution equations are derived to analyze the performance of the iterative receiver. To accelerate the convergence speed and reduce the complexity of joint demodulation and decoding, a novel serial schedule is proposed. Numerical results show that the joint demodulation and decoding for SCDT based on JSG can significantly improve the system's performance, while roughly half of the iterations can be saved by using the proposed serial schedule.

• 대한산업공학회지
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• 제20권3호
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• pp.65-77
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• 1994

There are so many situations in which production schedules need to be rescheduled, due to the uncertainty or dynamic characteristics existing in manufacturing environment. Under the circumstances, it is necessary to build a system which helps a schedule manager understand the dynamic situations and reflect his insight into the system easily. We developed a system that can improve a production schedule. The system consists of a schedule editor and a schedule generator. The schedule editor, a rule-based system, always keeps a schedule feasible by keeping track of local changes in the revised one. The schedule generator consists of a two-phase heuristic method. In the lst phase it generates a schedule by a priority rule with Giffler and Thompson algorithm then it improves the performance in terms of the makespan in the 2nd phase. Experimental results show that, most of the times, the system generates a better schedule than the one with ordinary priority rules only.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.90-91
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• 2014

Previous research related to the construction schedule management has focused on construction schedule categorization, construction schedule management, and system development to manage construction schedule risks. Therefore this research present quantitively deducing method for managing construction schedule risk. Based on the investigation, this study suggested the probable risk factors and a practical management method, through interviews and discussions with experts. The quantified risks should be adapted for an individually specific projects and managed until the project is complete. To maintain the continuity of schedule risks, the schedule risk management procedures should be controlled during the performance of the construction project.