• Journal of Korea Technology Innovation Society
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• v.2 no.3
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• pp.118-128
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• 1999

This study attempts to provide an efficient method for managing the Nuclear R&D projects. It should be noted that the technology and experiences to develop a well-balanced plan and mon-itoring for the R&D project are not yet well established when compared with the commercial con-structionand engineering projects. This study recommends that the R&D project manager utilize the scheduling techniques to establish an integral management system taking in to account the un-certainties in the research environment. Based upon the results of a case study for the Liquid Metal Reactor Design Technology Development Project which is led by the KAERI this study also con-firms that it is possible to run the national nuclear R&D projects with the Scheduling & Planning.

• Journal of Korean Institute of Industrial Engineers
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• v.43 no.1
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• pp.1-11
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• 2017

Stochastic resource-constrained project scheduling problem is an extension of resource-constrained project scheduling problem such that activity duration has stochastic nature. In real situation where activity duration is not known until the activity is finished, open-loop based static policies such as activity-based policy and priority-based policy will not well cope with duration variability. Then, a dynamic policy based on closed-loop decision making will be regarded as an alternative toward achievement of minimal makespan. In this study, a dynamic policy designed to select activities to start at each decision time point is illustrated. The performance of static and dynamic policies based on variable neighborhood search is evaluated under the discrete-event simulation environment. Experiments with J120 sets in PSPLIB and several probability distributions of activity duration show that the dynamic policy is superior to static policies. Even when the variability is high, the dynamic policy provides stable and good solutions.

• Korean Journal of Construction Engineering and Management
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• v.8 no.6
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• pp.235-245
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• 2007

This research study presents the development and application of an Elitist Genetic Algorithm (Elitist GA) for solving the resource-constrained project scheduling problem, which is one of the most challenging problems in construction engineering. Main features of the developed algorithm are that the elitist roulette selection operator is developed to preserve the best individual solution for the next generation so as to obtain the improved solution, and that parallel schedule generation scheme is used to generate a feasible solution to the problem. The experimental results on standard problem sets indicate that the proposed algorithm not only produces reasonably good solutions to the problems over the heuristic method and other GA, but also can find the optimal and/or near optimal solutions for the large-sized problems with multiple resources within a reasonable amount of time that will be applicable to the construction industry. This paper will help researchers and/or practitioners in the construction project scheduling software area with alternative means to find the optimal schedules by utilizing the advantages of the Elitist GA.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.395-398
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• 2011

This paper introduces stochastic cash-flow modeling integrated with simulation based scheduling. The system makes use of CPM schedule data exported from commercial scheduling software, computes the best fit probability distribution functions (PDFs) of historical activity durations, assigns the PDFs identified to respective activities, simulates the schedule network, computes the deterministic and stochastic project cash-flows, plots the corresponding cash flow diagrams, and estimates the best fit PDFs of overdraft and net profit of a project. It analyzes the effect of different distributions of activity durations on the distribution of overdrafts and net profits, and improves reliability compared to deterministic cash flow analysis.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.303-305
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• 2012

This paper presents a system called a Cash-flow based Construction Scheduling Optimization (CfSO). The existing CPM is biased on schedule and cost management. For a profitable and successful project management, the cash-flow which occurred actually by contractual conditions should be considered in the project scheduling. Therefore, this study provides a method to estimate the amount of a cash-flow occurred periodically by integrating the terms of contract into scheduling. The proposed methodology is implemented as a system prototype in Microsoft Excel. CfSO helps a site manager as a decision-maker to establish a optimized project scheduling and decide profitable contractual conditions against a construction owner.

• Journal of the Korea Safety Management & Science
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• v.9 no.5
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• pp.67-78
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• 2007

This paper discusses a scheduling problem on object-oriented developments over multiple teams with limited resources in matrix organization. The objective of the problem is to minimize the makespan of overall projects. There are tangible and intangible advantages such as efficient resource share, improvement of productivity, development efforts and cost reduction, etc. by dispatching resources properly to the development teams. Traditionally, the project scheduling has been done with a manager's intuition or heuristic. We present a scheduling model with illustrative examples, stochastic search approach, and apply a variety of problems generated randomly to the approach. The results are analysed.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.468-473
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• 2011

The goal of a project manager is generally to minimize the cost of the project and also to cope with uncertainty. This paper deals with the problem of project scheduling a set of activities satisfying precedence constraints in order to minimize the sum of the costs associated with the starting times of the activities in the network with imprecise activity durations, represented by means of interval or fuzzy numbers. So far this problem has been completely solved by several authors when the activities durations have crisp values. However, they do not consider the imprecision in activity durations in their models. Here the framework of possibility theory is proposed to solve this problem. In fuzzy arithmetic, usually, the interval calculations are used for the aim of complexity reduction and simplification. Thus the case of interval-valued durations is first addressed, and then extended to fuzzy intervals. A numerical example is used to illustrate the developed concept.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.117-121
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• 2015

Construction managers use scheduling methods to improve the outcome of their project. Despite the many obvious advantages of the critical path method (CPM), its use in construction has been limited. Understanding the reasons why CPM is not used as extensively as expected could improve its level of acceptance in the construction industry. The link between construction scheduling methods and the tasks expected to be performed by schedulers has been an on-going concern in the construction industry. This study proposes a task-technology fit model to understand why CPM is not used as extensively as expected in construction scheduling. A task-technology fit model that aims to measure the extent to which a construction scheduling method functionally matches the tasks expected to be performed by the scheduling staff. The model that is proposed is an answer to the lack of proper instruments for evaluating the extent to which scheduling methods are used in the industry.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.631-635
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• 2015

Construction managers use scheduling methods to improve the outcome of their project. In spite of the many obvious advantages of the critical path method (CPM), its use in construction has been limited. Understanding the reasons why CPM is not used as extensively as expected could improve its level of acceptance in the construction industry. The link between construction scheduling methods and the capabilities of the scheduling staff has been an on-going concern in the construction industry. This study proposes a staffing-technology fit model to understand why CPM is not used as extensively as expected in construction scheduling. A staffing-technology fit model that aims to measure the extent to which a construction scheduling method matches the staff's experience, know-how and capabilities. The model that is proposed is an answer to the lack of proper instruments for evaluating the extent to which scheduling methods are used in the industry.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1468-1473
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• 2009

Efficient communication of construction information has been critical for successful project performance. Building Information Modeling (BIM) has appeared as a tool for efficient communication. Through 3D CAD objects, it is possible to check interception and collisions of each object in advance. In addition, 4D simulation based on 3D objects integrated with time information makes it realize to go over scheduling and to perceive potential errors in scheduling. However, current scheduling simulation is still at a stage of animation due to manual integration of 3D objects and scheduling data. Accordingly, this study aims to develop an integrated model of 3D CAD objects that automatically creates scheduling information.