• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.193-198
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• 2009

It is an important issue in cost management to contract with the standard of cost estimate by the reasonable way in public construction projects. For the standard of cost estimate based on the Standard Estimating System, there is a difference of labor inputs between Standard Estimating System and actual quantities in construction projects. The duration of form work in multi-family housing depends on the manpower compared with other work, which is the critical path on the schedule management to be decided quality, and is the important to the cost management of construction projects. This study presented a simulation model of the productivity analysis for selecting the standard work type of form work in Multi-family housing construction projects.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.05a
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• pp.79-81
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• 2019

Collecting data in wireless sensor networks in minimum time is a traditional problem which is known NP-hard. Previous studies built the schedule using the node-based or link-based metrics to prioritize the transmissions. In this work, we combine the effect of both metrics to obtain a smaller aggregation time. We compare our work with state of the art schemes and report the improvement.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.585-588
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• 2003

This study attempts to develop a skeleton model to link construction schedule and 3D object for drawings in 4D system. Generally, the construction schedule and 3D object can be linked in 4D system by imported files which are made in specific S/Ws such as CAD S/W and scheduling S/W. Those methods have a difficulties for operating 4D data because extra work needs to link 4D data for each activity. This study develops a 4D model which the 4D data can be self-generated within the system. The suggested model can reduce the initial input data for new project by integrating schedule and 3D object in 4D system.

• Korean Journal of Construction Engineering and Management
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• v.12 no.1
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• pp.23-32
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• 2011

Domestic leading construction companies has been establishing and performing TACT scheduling method, similar to linear scheduling model such as line of balance and repetitive schedule, and etc. in which repetitive construction works are involved like high-rise building. Linear scheduling model has been researched as a visual scheduling method presenting the work space and time information. Likewise scheduling constraints of CPM network such as finish-to-finish, start-to-start, finish-to-start, start-to-start, linear scheduling model also has the relationships constraints, namely boundary conditions, between activities. It is especially necessary to define the boundary conditions of the activities' relationships in order to apply the linear scheduling model to be compatible with the network schedule. Therefore, this research considers the boundary conditions between activities for establishing the linear scheduling model. This paper also applies the proposed boundary conditions to TACT schedule and then deduces the main considerations in order to establish and perform TACT schedule.

• Korean Journal of Construction Engineering and Management
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• v.5 no.4 s.20
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• pp.87-96
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• 2004

The construction duration in apartment construction is an important factor which affects project cost. Henceforth, the time shortening is essential to retrench project cost and project risk when there adopt Five-Day Workweek and introduce apartment sales after completion of construction. Therefore, the purpose of this study is to examine closely the affecting factors on the duration of framework which forms about $40\sim50\$ percent of total time in apartment construction by analyzing the schedule mechanism of typical floor and to show the reasonable time shortening methods by case study. The shown schedule mechanism and basic schedule table can utilize as a guideline in case of scheduling of framework in the existing construction method. Also, the shown time shortening methods by three case studies will guide the direction and process of time shortening while there need time shortening in many-sided projects.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.6
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• pp.861-868
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• 2022

A key use of applying building information modeling (BIM) to the construction stage of a project is to help identify construction obstacles and to visualize construction status according to the progress of the construction schedule. When employing 4D simulation for this purpose, start and finish dates for each activity and a 3D model of the activity must be prepared. In this work, in order to simplify the configuration of a 4D model, minimum attribute information of the BIM model produced in the design stage was used to construct a system that generated activity information in the construction stage using a clustering algorithm. Its usefulness as actual schedule management information was then analyzed.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.397-402
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• 2013

In super-tall building construction projects, schedule risk factors which vertically change and are not found in the low and middle-rise building construction influence duration of a project by vertical attribute; and it makes hard to estimate activity or overall duration of a construction project. However, the existing duration estimating methods, that are based on quantity and productivity assuming activities of the same work item have the same risk and duration regardless of operation space, are not able to consider the schedule risk factors which change by the altitude of operation space. Therefore, in order to advance accuracy of duration estimation of super-tall building projects, the degree of changes of these risk factors according to altitude should be analyzed and incorporated into a duration estimating method. This research proposes a simulation model using Monte Carlo method for estimating activity duration incorporating schedule risk factors by weather conditions in a super-tall building. The research process is as follows. Firstly, the schedule risk factors in super-tall building are identified through literature and expert reviews, and occurrence of non-working days at high altitude by weather condition is identified as one of the critical schedule risk factors. Secondly, a calculating method of the vertical distributions of the weather factors such as temperature and wind speed is analyzed through literature reviews. Then, a probability distribution of the weather factors is developed using the weather database of the past decade. Thirdly, a simulation model and algorithms for estimating non-working days and duration of each activity is developed using Monte-Carlo method. Finally, sensitivity analysis and a case study are carried out for the validation of the proposed model.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.1
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• pp.95-105
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• 2022

Recently, as the scale of a construction project has become larger and more complicated, there are many cases where construction projects with complex structures are carried out in a fast track method to save construction duration. In the fast track method, the proper division of construction phases is an important issue in determining the overall project period. This study presents a rational phase division method that can be applied when a construction project with complex structures is carried out as a fast track. For this study, a subdivided work breakdown structure (WBS) is developed using the construction of 4 soccer stadiums as application examples, and the schedule is analyzed by dividing the construction process of major phases. To this end, five proposals are applied to analyze the adequacy of the fast track phase division. For the draft with the minimum construction period, the fast track phase division and the schedule model of by each phase were presented. This methodology can have an application in the appropriate phase division and schedule model by construction phase when fast track is applied in large construction project of a similar size.

• Korean Journal of Construction Engineering and Management
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• v.12 no.6
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• pp.54-64
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• 2011

Almost 40 years have been passed since the CPM was introduced to the construction industry in Korea. However most of construction projects in Korea do not prepare the CPM schedule neither operate it after established manually, as well as still depend on the Bar-chart schedule only. One of these reasons is because the CPM schedule does not reflect the site works realistically, it makes so difficult to recognize the actual progress clearly in visual format, and it is impossible to integrate and manage the time and cost oriented work progresses effectively. This paper proposes new concept of progress management that is able to integrate and manage the time oriented schedule progress and earned value oriented cost progress while maintaining the merits of CPM although the CPM schedule summarized automatically within a schedule hierarchy by the BDM that is a new CPM technique. We expect that this concept could make the applications of CPM technique to the domestic construction industry popular and help the advancement of the construction management in Korea as well.

• Korean Journal of Construction Engineering and Management
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• v.6 no.5 s.27
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• pp.139-147
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• 2005

During a typical construction project, a contractor nay often find that the time originally available or normally expected to perform its work has been severely reduced. To finish the project by the completion date, the contractor is forced to find a way to speed up the progress of its work to compensate for the reduction in available time. The most frequent initial reaction of contractors to this situation is to increase on-site manpower by working longer time (overtime), adding more workers (overmanning), or implementing shift work (shift work) to increase the rate of progress. The goals of this study were to investigate how these three methods affect labor productivity and to quantify their impact on labor productivity by analyzing real project data collected from sheet metal contractors and mechanical contractors in the US.