• 대한건축학회논문집:구조계
• /
• 제34권2호
• /
• pp.67-74
• /
• 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.

• 국제학술발표논문집
• /
• The 1th International Conference on Construction Engineering and Project Management
• /
• pp.558-563
• /
• 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.

• 산업경영시스템학회지
• /
• 제43권2호
• /
• pp.79-86
• /
• 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.

• 한국건설관리학회:학술대회논문집
• /
• 한국건설관리학회 2004년도 제5회 정기학술발표대회 논문집
• /
• pp.575-578
• /
• 2004

건설프로젝트는 일정한 기간 동안 주어진 목표를 수행하기 위한 작업들의 모임이라 정의할 수 있으며, 이를 위해서는 필요한 자원의 효율적 계획 및 관리가 필요하고, 이때 자원배당 및 자원평준화 기법이 활용된다. 하지만 자원제약이 있는 자원배당과 공기 제한이 있는 자원평준화 방법은 하나의 프로젝트에 개별적으로 적용되고 있어 전체 프로젝트의 공기와 효율적 자원이용 측면에서 적정화하기는 어렵다. 따라서 본 연구는 자원 평준화 방법의 Minimum Moment Algorithm 개념을 확대 $\cdot$ 적용하여 적정 자원이용 및 공사기간을 산출하고자 한다. 이때 자원 활용의 상태를 나타내는 5가지 지표들 사이의 중요도는 AHP기법을 통해 파악한다.

• 한국염색가공학회:학술대회논문집
• /
• 한국염색가공학회 2009년도 학술발표대회
• /
• pp.175-176
• /
• 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.

• 한국건설관리학회논문집
• /
• 제5권5호
• /
• pp.126-134
• /
• 2004

건설프로젝트는 일정한 기간 동안 주어진 목표를 수행하기 위한 작업들의 모임이라 정의할 수 있으며, 이를 위해서는 필요한 자원의 효율적 계획 및 관리가 필요하고, 이때 자원배당 및 자원평준화 기법이 활용된다. 하지만 자원제약이 있는 자원배당과 공기 제한이 있는 자원평준화 방법은 하나의 프로젝트에 개별적으로 적용되고 있어 전체 프로젝트의 공기와 효율적 자원이용 측면에서 적정화하기는 어렵다. 따라서 본 연구는 자원 평준화 방법의 Minimum Moment Algorithm 개념을 확대$\cdot$적용하여 적정 자원이용 및 공사기간을 산출하고자 한다. 이때 자원 활용의 상태를 나타내는 5가지 지표가 사용되며, 이들간의 중요도를 파악하기 위해 공정전문가를 대상으로 설문조사를 실시하였다. 마지막으로 가상 프로젝트의 적용을 통해 본 모형의 적용 가능성을 검증하고자 하였다.

• 산업공학
• /
• 제12권3호
• /
• pp.354-361
• /
• 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.

• 산업공학
• /
• 제16권3호
• /
• pp.332-343
• /
• 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.

• 한국국방경영분석학회지
• /
• 제3권1호
• /
• pp.123-136
• /
• 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.

• 한국건설관리학회논문집
• /
• 제5권5호
• /
• pp.135-142
• /
• 2004

본 연구에서는 바차트(bar chart) 기법과 CPM 기법의 장점을 결합한 CPM bar chart(CBC) 기법을 제시한다. CBC는 기존의 fenced bar chart(FBC)의 장점을 유지하면서 단점을 보완한 것으로, 작업 관계를 나타내는 fence에 방향성을 부여함으로써, 기존 FBC에서 상당한 혼란을 유발하는 fence의 분리과정 없이 작업들의 관계를 표현할 수 있다. 또한, fence의 분리를 파악하기 위해 더미작업(dummy activity)을 확인하는 과정이 생략되어 보다 손쉽게 작성할 수 있는 장점도 있다. 바차트의 간결성을 유지하면서 CPM의 네트워크 논리 표현이 가능해짐에 따라, CBC는 다양한 프로젝트 참여자들 간의 원활한 의사소통에 기여하리라 예상된다. 또한, resource constrained scheduling, resource leveling, 작업 분리가 고려된 일정 조정, 공기 지연 분석 등의 CPM 기법에 기초한 다양한 일정 계획 및 관리에도 적용이 용이하여, 실무뿐만이 아니라 공정관리 교육과정에서도 활용성이 높으리라 기대된다.