• 한국건설관리학회논문집
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• 제24권5호
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• pp.73-82
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• 2023

Optimization of Construction Site Layout Planning (CSLP) heavily relies on workers' travel paths. However, traditional path generation approaches predominantly focus on the shortest path, often neglecting critical variables such as individual wayfinding tendencies, the spatial arrangement of site objects, and potential hazards. These oversights can lead to compromised path simulations, resulting in less reliable site layout plans. While Deep Reinforcement Learning (DRL) has been proposed as a potential alternative to address these issues, it has shown limitations. Despite presenting more realistic travel paths by considering these variables, DRL often struggles with efficiency in complex environments, leading to extended learning times and potential failures. To overcome these challenges, this study introduces a refined model that enhances spatial navigation capabilities and learning performance by integrating workers' visibility into the reward functions. The proposed model demonstrated a 12.47% increase in the pathfinding success rate and notable improvements in the other two performance measures compared to the existing DRL framework. The adoption of this model could greatly enhance the reliability of the results, ultimately improving site operational efficiency and safety management such as by reducing site congestion and accidents. Future research could expand this study by simulating travel paths in dynamic, multi-agent environments that represent different stages of construction.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2006년도 정기학술발표대회 논문집
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• pp.74-79
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• 2006

정부정책 수립자들은 일반적으로 정책들의 종합적이고 전체적인 영향을 제대로 고려하지 못하고 개개의 정책목표만을 달성하려는 경향이 있다. 또한 전형적인 정책결정 관행은 산업참여자들의 다양한 요구와 그들의 공공정책에 대한 반응을 제대로 고려하지 못하고 있다. 본 연구는 이 쟁점을 검토하기 위해 시뮬레이션 모델 베이스 접근법의 하나인 시스템 다이내믹스 모델을 이용하여 공공정책의 효과성윤 체계적으로 평가한 수 있는 방법을 제안하였으며, 건설 생산성을 강화하기 위한 싱가포르 정부의 정책들을 사례로 적용하였다. 이러한 시뮬레이션 모델을 이용하여 싱가포르 정부의 정책을 분석하였다. 모델 구조와 시뮬레이션 결과로부터 얻은 정책의 함축적 의미와 인과관계들을 토대로 정부 정책 수립을 보다 효과적으로 만들 수 있는 제안과 고려사항들을 제시하였다. 이러한 연구결과를 바탕으로, 시뮬레이션 모델 기반의 접근 방법이 건설정책 수립과 분석에 유용하게 활용될 수 있음을 파악하였다.

• Structural Monitoring and Maintenance
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• 제8권4호
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• pp.361-378
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• 2021

While the pavement rating system is being utilized for periodic road condition assessment in the Eastern Region municipality of Saudi Arabia, the condition assessment is costly, time-consuming, and not comprehensive as only few parts of the road are randomly selected for the assessment. Thus, this study is aimed at developing a condition assessment model for a specific sample of a residential road network in Dammam City based on an individual road and a road network. The model was developed using the Analytical Hierarchy Process (AHP) according to the defect types and their levels of severity. The defects were arranged according to four categories: structure, construction, environmental, and miscellaneous, which was adopted from sewer condition coding systems. The developed model was validated by municipality experts and was adjudged to be acceptable and more economical compared to results from the Eastern region municipality (Saudi Arabia) model. The outcome of this paper can assist with the allocation of the government's budget for maintenance and capital programs across all Saudi municipalities through maintaining road infrastructure assets at the required level of services.

• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.662-671
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• 2007

Since variety of construction projects with their individual specifications could be handled through different procurement systems, selection of the most appropriate project delivery system is a vital step towards more efficient project execution. The appropriate selection of project delivery system may also ensure more competent management of the project. Its impacts are not only limited to the first stages of the project, as it could also influence pre-construction, construction and operational phases of the project. Among different approaches exerted for this purpose, none has taken uncertainty into account, despite the fact that during first stages of the project most of the selection factors are still uncertain and not clearly defined. This paper, hence, aims to provide a fuzzy insight into the project delivery system selection. Through this approach more tangible model of the evaluation process may be presented. Proposed fuzzy method is indeed a multi criteria decision making model, based on the group of criteria, assigned for the evaluation procedure. A case study is also conducted, based on the opinion of an invented group of the experts.

• 국제학술발표논문집
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• The 5th International Conference on Construction Engineering and Project Management
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• pp.539-545
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• 2013

Although individual-level factors (e.g., attitudes, personality) have long been associated with day-to-day attendance decisions, increasingly researchers have recognized "the social nature of attendance dynamics and their susceptibility to social control (Johns, 2008)." Implications of this social approach for research would be to focus attention on the causes and effects of absence culture (i.e., absence-related perceptions, beliefs, values), and the effects of absence culture on individual and group attendance within social units. Construction projects typically require workers to work in teams or crews on highly interdependent projects, and, thus, are particularly relevant contexts to study absence culture. In this paper we apply a system dynamics (SD) model to study absence culture by utilizing the advantages of SD in capturing a feedback process and state changes. We were particularly interested in: (a) the awareness of social norms within construction crews that pertained to attendance, (b) the interplay between formal attendance rules (policy) and these social norms, and (c) how these sources of influence affected the decision-making process of construction crew members. We expect that the results of this work will help construction organizations evaluate (or re-consider) the effects of their attendance control policies (e.g., timing, strength, and frequency) within a social context. Moreover, our findings suggest that the key to reducing excessive absences might be to invest time in influencing absence culture directly rather than imposing frequent and strict regulations - which, in turn, may inadvertently fortify a culture that works against the organization's interests.

• 한국건설관리학회논문집
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• 제24권6호
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• pp.36-44
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• 2023

입찰담합에 따른 공공재정 손실, 경쟁 저해, 신뢰 하락 등의 문제에 대응하기 위해, 공공 건설공사 입찰실무자의 담합 가능성을 예측하고 대응 방안을 개발하는 것을 목적으로 한다. 이를 위해 FTT (Fraud Triangle Theory)의 기회, 압력, 합리화 요인을 분석하여 입찰담합 예방 및 대응 방안을 도출한다. 종합·전문 건설업체의 입찰실무자를 대상으로 한 설문 조사를 통해 FTT 연구모형을 검증하고, 결과를 통해 입찰실무자의 담합 가능성을 예측하는 데 활용한다. 연구 결과, 압력이 높을수록, 기회가 많을수록, 합리화가 강할수록 개인의 담합 가능성이 커지는 것을 확인하였다. 또한, 기회가 많을수록, 합리화가 강할수록 타인의 담합 가능성도 커지는 것을 알 수 있었다. 이러한 현상을 이해하여 입찰담합 예방을 위한 정책 개발에 기여할 것으로 기대된다.

• 대한치과교정학회지
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• 제50권4호
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• pp.229-237
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• 2020

Objective: To evaluate the construction reproducibility of a composite tooth model (CTM) composed of an intraoral-scanned crown and a cone-beam computed tomography (CBCT)-scanned root. Methods: The study assessed 240 teeth (30 central incisors, 30 canines, 30 second premolars, and 30 first molars in the maxillary and mandibular arches) from 15 young adult patients whose pre-treatment intraoral scan and CBCT were available. Examiner-Reference (3 years' experience in CTM construction) and Examiners-A and Examiner-B (no experience) constructed the individual CTMs independently by performing the following steps: image acquisition and processing into a three-dimensional model, integration of intraoral-scanned crowns and CBCT-scanned teeth, and replacement of the CBCT-scanned crown with the intraoral-scanned crown. The tooth axis angle in terms of mesiodistal angulation and buccolingual inclination of the CTMs constructed by the three examiners were measured. To assess the construction reproducibility of CTMs, intraclass correlation coefficient (ICC) assessments were performed. Results: The ICC values of mesiodistal angulation and buccolingual inclination among the 3 examiners showed excellent agreement (0.950-0.992 and 0.965-0.993; 0.976-0.994 and 0.973-0.995 in the maxillary and mandibular arches, respectively). Conclusions: The CTM showed excellent construction reproducibility in mesiodistal angulation and buccolingual inclination regardless of the construction skill and experience levels of the examiners.

• 한국건축시공학회지
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• 제13권4호
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• pp.372-381
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• 2013

In the construction industry, a great deal of research has been focused on productivity improvement because a minor change in labor productivity can often make the difference between a profit and a loss. This study shows how productivity measurement methods can be applied in practice, step by step, to analyze and identify potential problems both in productivity and methods performance for masonry work. A work sampling technique was conducted to determine the nature and extent of an observable activity as an aid to measuring overall performance. Also, a method productivity delay model was used to identify non-productivity in individual cycle times. From the work sampling technique, it was found that the masonry crew had a Labor Utilization Factor of 47.1%, and from the videotape analysis, it was found that the material and dumpster location need to be adjusted to reduce the travelling distance. We have found that efforts to improve the productivity of masonry work should be focused almost exclusively on machine and labor delays, based on the result from the method productivity delay model.

• 한국강구조학회 논문집
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• 제24권1호
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• pp.1-11
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• 2012

군중하중을 받는 현행 바닥진동 설계절차의 한계를 극복하기 위해서는 개인별 운동의 시간차와 운동성분에 내재된 위상의 불확실성이 고려되어야 한다. 개인의 운동에 관한 연구는 통계적 자료를 토대로 많은 연구가 진행되고 있는 반면, 군중 행동패턴에 관한 연구는 그 복잡성으로 인해 연구가 미흡한 실정이다. 본 연구에서는 다양하고 복잡한 군중의 행동패턴을 개인 간의 위상을 반영한 하중모형을 제안한다. 모의실험을 통해 개인의 시간지연 값들을 난수로 발생시킨 후, 기준시간에 대한 시간 지연효과를 합산하였다. 본 연구에서 제안하는 위상의 합산으로 이루어진 계수는, 완전히 동기화된 군중의 경우에 대한 동기화 정도의 비를 나타낼 수 있다. 정의된 계수를 바탕으로 실제 일어날 수 있는 군중의 행동패턴을 분석하여 각각의 경우에 대한 계수 값을 제안하였다. 본 연구의 결과를 토대로 기존의 설계방식이 다룰 수 없었던 군중의 운동시 바닥구조의 응답을 합리적으로 반영할 수 있다.

• 한국철도학회논문집
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• 제18권4호
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• pp.344-353
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• 2015

최근 BIM의 활용이 시각적인 3D모델링 이외에 일정 및 공사비 시뮬레이션, 시각적 공사현황관리, 증강현실적용 등으로 확장되면서, 이에 따른 다양한 BIM기능들이 개발되고 있다. 그러나 개발되는 기능들에 대해 명확한 분류기준과 지식정보가 부족하여, 공사프로젝트에 필요한 기능들을 파악하는데 어려움이 있다. 따라서 본 연구에서는 서로 다른 BIM기능의 특성을 반영하여 BIM기능요소 분류체계를 구성하고, 이를 기반으로 BIM기능을 발주할 수 있는 발주모형 구성 방안을 제시하고자 한다. 이로써, 철도시설사업에 적용할 수 있는 BIM기능을 분석하여 실무적 활용성을 높이고자 하였으며, 사례적용을 통해 활용성을 검증하고 있다.