• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.2
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• pp.67-74
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• 2018

Resource leveling minimizes resource fluctuations by deferring the earliest start times (ESTs) of non-critical activities within their corresponding total float. The intentional float-consumption for resource leveling purpose reduces the schedule delay contingency. This paper presents a method called Genetic Algorithm based Resource Leveling (GARL) that minimizes resource fluctuations and float-consumption impact over project duration. It identifies activities that are less sensitive to float-consumption and performs resource leveling using those activities. The study is of value to project scheduler because GARL identifies the set of activities to be deferred and the number of shift day(s) of each and every activities in the set within its total float expeditiously. It contributes to establish a baseline schedule which implements an optimal resource leveling plan. A case study is presented to verify the validity and usability of the method. It was confirmed that GARL satisfies the project duration constraint by considering resource fluctuations and float-consumption over project duration.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.558-563
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• 2005

This paper presents a GA-based optimal algorithm for a resource leveling model that levels the resources of a set of non-critical activities experiencing conflicts simultaneously up to an assumed level of resource rates specified by the planner using a pair-wise comparison of the activities being considered. A parameter called the future float is adopted and applied as an indicator for assigning leveling priorities to the sets of activities experiencing conflicts. A construction project network example was worked out to demonstrate the performance of the proposed method. The histogram obtained using the algorithm proposed was shown to be the same as, or very close to that produced by the existing resource leveling method based on the least total float rule, which shifts non-critical activities individually.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.2
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• pp.79-86
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• 2020

To make a satisfactory decision regarding project scheduling, a trade-off between the resource-related cost and project duration must be considered. A beneficial method for decision makers is to provide a number of alternative schedules of diverse project duration with minimum resource cost. In view of optimization, the alternative schedules are Pareto sets under multi-objective of project duration and resource cost. Assuming that resource cost is closely related to resource leveling, a heuristic algorithm for resource capacity reduction (HRCR) is developed in this study in order to generate the Pareto sets efficiently. The heuristic is based on the fact that resource leveling can be improved by systematically reducing the resource capacity. Once the reduced resource capacity is given, a schedule with minimum project duration can be obtained by solving a resource-constrained project scheduling problem. In HRCR, VNS (Variable Neighborhood Search) is implemented to solve the resource-constrained project scheduling problem. Extensive experiments to evaluate the HRCR performance are accomplished with standard benchmarking data sets, PSPLIB. Considering 5 resource leveling objective functions, it is shown that HRCR outperforms well-known multi-objective optimization algorithm, SPEA2 (Strength Pareto Evolutionary Algorithm-2), in generating dominant Pareto sets. The number of approximate Pareto optimal also can be extended by modifying weight parameter to reduce resource capacity in HRCR.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.575-578
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• 2004

Since a construction project is a series of works that utilizes resources to accomplish the project goal for a given time period, efficient resource management is a prerequisite for the success of the project. Two major areas of resource management are resource constrained scheduling focusing on the limited resource availability and resource leveling focusing on smoothing resource usage pattern on the fixed project completion time. It is not available, however, to apply both techniques to a project at the same time. This paper proposes a model to enhance the minimum moment algorithm of resource leveling, aiming to find an efficient usage of resources and an appropriate project completion time. A survey is performed to evaluate the major five factors using the AHP.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2009.03a
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• pp.175-176
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• 2009

Energy saving and environment-friendly dyeing method of cotton with reactive dyes is the ultra low liquor ratio dyeing because it reduces the total quantity of water, dye, salt and alkali during the dyeing process in the effluent as well as the energy consumption. However, this method may not guarantee the quality of the dyeing results due to the specs or unlevel dyeing depending upon the dyes used. The study has focused on the effect of leveling agents in the dyeing of cotton with reactive dyes under the ultra low liquor ratio (1:5). Especially Sunfix N/B MF-D which was selected for ULLR showed low-leveled dyeing comparing with the other MF-D series. A leveling agent having polycarbonate structure increased LDF values of Sunfix N/B MF-D without changing of dyeing fastness. We recommend some leveling agents to improve the leveling behavior for ULLR dyeing.

• Korean Journal of Construction Engineering and Management
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• v.5 no.5 s.21
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• pp.126-134
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• 2004

Since a construction project is a series of works that utilizes resources to accomplish the project goal for a given time period, efficient resource management is a prerequisite for the success of the project. Two major areas of resource management are resource constrained scheduling focusing on the limited resource availability and resource leveling focusing on smoothing resource usage pattern on the fixed project completion time. It is not available, however, to apply both techniques to a project at the same time. This paper proposes a model to enhance the minimum moment algorithm of resource leveling, aiming to find an efficient usage of resources and an appropriate project completion time. A survey was performed to evaluate the major five factors in the model. A case study demonstrates the value of the proposed resource leveling technique.

• IE interfaces
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• v.12 no.3
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• pp.354-361
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• 1999

In this paper, resource leveling heuristics are developed for ship erection scheduling. The heuristics, which enable scheduling with limited resources, are composed of the gradual resource limit decrease anti the resource allocation. At first, earliest start(ES) schedule is derived by PERT to get initial resource limit. And then, the heuristics lower the resource limits by a given increment and derive a new schedule from day-by-day resource allocation procedure. The procedure is repeated until the project duration reaches at the given ship erection duration, called dock cycle. Through the application of the heuristics for real world ship erection projects, wc can observe significant improvement in resource leveling.

• IE interfaces
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• v.16 no.3
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• pp.332-343
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• 2003

This paper deals with pre-erection scheduling and erection scheduling in shipbuilding. Among shipbuilding scheduling, the ship erection scheduling in a dock is one of the most important since the dock is the most critical resource in a shipyard. However, it is more reasonable to consider pre-erection scheduling and erection scheduling as unified because they compete with the common constrained resources such as labor, crane, space, and so on. It is very hard to consider two scheduling problems simultaneously, and hence, we approach them sequentially. At first, we propose space resource leveling heuristics in pre-erection scheduling given erection date. And then, considering the manpower resource determined by pre-erection scheduling, we also propose manpower resource leveling heuristics in erection scheduling. Various experimental results with real world data show that the proposed heuristics have good performance in terms of scheduling quality and time.

• Journal of the military operations research society of Korea
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• v.3 no.1
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• pp.123-136
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• 1977

This thesis presents a modification and extension to the Burgess and Killebrew heuristic resource leveling procedure for project networks. In contrast to previous algorithms appearing in the literature, the objective function of this algorithm. is the minimization of the sum of the squared errors in each time period (deviations around the mean usage) of all resources over the duration of the project. This objective function continues the search for an improved schedule beyond that of previous algorithms with their associated objective functions. One important feature is that the algorithm tends to reduce the number of periods that a resource is idle during its duration on the project.

• Korean Journal of Construction Engineering and Management
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• v.5 no.5 s.21
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• pp.135-142
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• 2004

This paper proposes the CPM bar chart (CBC), a hybrid of the bar chart and the critical pad method (CPM). The CBC overcomes shortages of the fenced bar chart, while still keeping advantages. The fence with direction is applied instead of the broken fence, which triggers considerable problems to identify and apply in the fenced bar chart. In addition, the notorious task to find dummy activities is no longer required. Upon the benefits of simplicity in the bar chart and logical work sequence in the CPM network. the CBC provides a relatively easy way to create and understand a schedule, thus improving communication quality between project participants. With the advantages, the CBC can also be effectively applied to various scheduling techniques such as resource constrained scheduling, resource leveling, scheduling with activity split, delay impact analysis, etc.