Time-cost optimization in repetitive project scheduling with limited resources

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xin Zou ◽  
Lihui Zhang ◽  
Qian Zhang
Keyword(s):  
Optimization Model ◽  
Cost Optimization ◽  
Residential Building ◽  
Indirect Costs ◽  
Limited Resource ◽  
Project Performance ◽  
Time Cost ◽  
Early Completion ◽  
Solution Quality ◽  
Content Type

PurposeThe purpose of this research is to develop a time-cost optimization model to schedule repetitive projects while considering limited resource availability.Design/methodology/approachThe model is based on the constraint programming (CP) framework; it integrates multiple scheduling characteristics of repetitive activities such as continuous or fragmented execution, atypical activities and coexistence of different modes in an activity. To improve project performance while avoiding inefficient hiring and firing conditions, the strategy of bidirectional acceleration is presented and implemented, which requires keeping regular changes in the execution modes between successive subactivities in the same activity.FindingsTwo case studies involving a real residential building construction project and a hotel refurbishing project are used to demonstrate the application of the proposed model based on four different scenarios. The results show that (1) the CP model has great advantages in terms of solving speed and solution quality than its equivalent mathematical model, (2) higher project performance can be obtained compared to using previously developed models and (3) the model can be easily replicated or even modified to enable multicrew implementation.Originality/valueThe original contribution of this research is presenting a novel CP-based repetitive scheduling optimization model to solve the multimode resource-constrained time-cost tradeoff problem of repetitive projects. The model has the capability of minimizing the project total cost that is composed of direct costs, indirect costs, early completion incentives and late completion penalties.

BIM-based time-cost optimization of a large-span spatial steel structure in an airport terminal building

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jingyu Yu ◽  
Jingfeng Wang ◽  
Zhengmao Hua ◽  
Xingxing Wang
Keyword(s):  
Optimization Model ◽  
Cost Optimization ◽  
Steel Structure ◽  
Steel Structures ◽  
Information Modeling ◽  
Time Cost ◽  
Aesthetic Quality ◽  
Content Type ◽  
Large Span ◽  
Airport Terminal

Purpose Airports are booming in China, to enlarge their capacities and stimulate economic development. Large-span spatial steel structures are commonly used in the terminal buildings of airport projects. Their advantages include prefabrication, strength, usability, adaptability and aesthetic quality. To manage large-span spatial steel structure projects, building information modeling (BIM) is recommended. Although there are plenty of studies on BIM application in steel structure projects, it is still rare to apply BIM to optimize the schedule and cost of steel structures, especially for airport projects. Design/methodology/approach This paper aims to develop a framework in which BIM and a time-cost optimization model are integrated to optimize construction costs and the duration of large-span spatial steel structure projects. A real case study was conducted to verify the feasibility of the BIM-based time-cost optimization model in an airport terminal building, which was built with a large-span spatial steel structure. Findings The results preliminarily support the reliability of the proposed BIM-based time-cost optimization model. The BIM-based time-cost optimization model will benefit construction planning for professionals and enrich relevant research on the application of BIM in large-span spatial steel structure projects. Originality/value The steel structure is difficult to control budgets and progress. This paper is expected to be adopted for optimizing the time and cost plans for projects involving steel structures in airport terminal buildings.

Multi-objective optimization for repetitive scheduling under uncertainty

2019 ◽  
Vol 26 (7) ◽  
pp. 1294-1320 ◽  
Author(s):  
Tarek Salama ◽  
Osama Moselhi
Keyword(s):  
Cost Optimization ◽  
Indirect Costs ◽  
Optimization Method ◽  
Multi Objective Optimization ◽  
Software Module ◽  
Content Type ◽  
Project Duration ◽  
Multi Objective ◽  
Work Interruptions ◽  
Cost Calculations

Purpose The purpose of this paper is to present a newly developed multi-objective optimization method for the time, cost and work interruptions for repetitive scheduling while considering uncertainties associated with different input parameters. Design/methodology/approach The design of the developed method is based on integrating six modules: uncertainty and defuzzification module using fuzzy set theory, schedule calculations module using the integration of linear scheduling method (LSM) and critical chain project management (CCPM), cost calculations module that considers direct and indirect costs, delay penalty, and work interruptions cost, multi-objective optimization module using Evolver © 7.5.2 as a genetic algorithm (GA) software, module for identifying multiple critical sequences and schedule buffers, and reporting module. Findings For duration optimization that utilizes fuzzy inputs without interruptions or adding buffers, duration and cost generated by the developed method are found to be 90 and 99 percent of those reported in the literature, respectively. For cost optimization that utilizes fuzzy inputs without interruptions, project duration generated by the developed method is found to be 93 percent of that reported in the literature after adding buffers. The developed method accelerates the generation of optimum schedules. Originality/value Unlike methods reported in the literature, the proposed method is the first multi-objective optimization method that integrates LSM and the CCPM. This method considers uncertainties of productivity rates, quantities and availability of resources while utilizing multi-objective GA function to minimize project duration, cost and work interruptions simultaneously. Schedule buffers are assigned whether optimized schedule allows for interruptions or not. This method considers delay and work interruption penalties, and bonus payments.

Time–cost–quality trade-off analysis for planning construction projects

2019 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Tianqi Wang ◽  
Moatassem Abdallah ◽  
Caroline Clevenger ◽  
Shahryar Monghasemi
Keyword(s):  
Optimization Model ◽  
Construction Projects ◽  
Present Model ◽  
Construction Project ◽  
Time Cost ◽  
Trade Off ◽  
Content Type ◽  
Project Duration ◽  
Trade Offs ◽  
Project Objectives

Purpose Achieving project objectives in constructionprojects such as time, cost and quality is a challenging task. Minimizing project cost often results in additional project duration and might jeopardize quality, and minimizing project duration often results in additional cost and might jeopardize quality. Also, increasing construction quality often results in additional cost and time. The purpose of this paper is to identify and analyze trade-offs among the project objectives of time, cost and quality. Design/methodology/approach The optimization model adopted a quantitative research method and is developed in two main steps formulation step that focuses on identifying model decision variables and formulating objective functions, and implementation step that executes the model computations using multi-objective optimization of Non-Dominated Sorting Genetic Algorithms to identify the aforementioned trade-offs, and codes the model using python. The model performance is verified and tested using a case study of construction project consisting of 20 activities. Findings The model was able to show practical and needed value for construction managers by identifying various trade-off solutions between the project objectives of time, cost and quality. For example, the model was able to identify the shortest project duration at 84 days while keeping cost under $440,000 and quality higher than 85 percent. However, with an additional budget of $20,000 (4.5 percent increase), the quality can be increased to 0.935 (8.5 percent improvement). Research limitations/implications The present research work is limited to project objectives of time, cost and quality. Future expansion of the model will focus on additional project objectives such as safety and sustainability. Furthermore, new optimization models can be developed for construction projects with repetitive nature such as roads, tunnels and high rise buildings. Practical implications The present model advances existing research in planning construction projects efficiently and achieving important project objectives. On the practical side, the optimization model will support the construction industry by allowing construction managers to identify the highest quality to deliver a construction project within specified budget and duration, lowest cost for specified duration and quality or shortest duration for specified budget and quality. Originality/value The present model introduces new and innovative method of increasing working hours per day and number of working days per shift while analyzing labor working efficiency and overtime rate to identify optimal trade-offs among important project objectives of time, cost and quality.

scholarly journals An optimization model of the acceptable consensus and its economic significance

Kybernetes ◽  
2016 ◽  
Vol 45 (1) ◽  
pp. 181-206 ◽  
Author(s):  
Zaiwu Gong ◽  
Xiaoxia Xu ◽  
Jeffrey Forrest ◽  
Yingjie Yang
Keyword(s):  
Information Entropy ◽  
Optimization Model ◽  
Optimal Solution ◽  
Limited Resource ◽  
Practical Significance ◽  
Content Type ◽  
Economic Significance ◽  
Consensus Opinion ◽  
Optimization Methodology ◽  
The Stability

Purpose – The purpose of this paper is to construct an optimal resource reallocation model of the limited resource by a moderator for reaching the greatest consensus, and show how to reallocate the limited resources by using optimization methodology once the consensus opinion is reached. Moreover, this paper also devotes to theoretically exploring when or what is the condition that the group decision-making (GDM) system is stable; and when new opinions enter into the GDM, how the level of consensus changes. Design/methodology/approach – By minimizing the differences between the individuals’ opinions and the collective consensus opinion, this paper constructs a consensus optimization model and shows that the objective weights of the individuals are actually the optimal solution to this model. Findings – If all individual deviations of the decision makers (DMs) from the consensus balance each other out, the information entropy theorem shows this GDM is most stable, and economically each individual DM gets the same optimal unit of compensation. Once the consensus opinion is determined and each individual opinion of the DMs is under an acceptable consensus level, the consensus is still acceptable even if additional DMs are added, and the moderator’s cost is still no more than a fixed upper limitation. Originality/value – The optimization model based on acceptable consensus is constructed in this paper, and its economic significance, including the theoretical and practical significance, is emphatically analyzed: it is shown that the weight information of the optimization model carries important economic significance. Besides, some properties of the proposed model are discussed by analyzing its particular solutions: the stability of the consensus system is explored by introducing information entropy theory and variance distribution; in addition, the effect of adding new DMs on the stability of the acceptable consensus system is discussed by analyzing the convergence of consensus level: it is also built up the condition that once the consensus opinion is determined, the consensus degree will not decrease even when additional DMs are added to the GDM.

Time-cost-quality-environmental impact trade-off resource-constrained project scheduling problem with DEA approach

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sayyid Ali Banihashemi ◽  
Mohammad Khalilzadeh
Keyword(s):  
Environmental Impacts ◽  
Cost Optimization ◽  
Project Managers ◽  
Time Cost ◽  
Quality Factors ◽  
Trade Off ◽  
Content Type ◽  
Execution Mode ◽  
Project Objectives ◽  
Efficient Execution

PurposeThe purpose of this paper is to evaluate project activities' efficiency in different execution modes for the optimization of time–cost-quality and environmental impacts trade-off problem.Design/methodology/approachThis paper presents a parallel Data Envelopment Analysis (DEA) method for evaluation of project activities with different execution modes to select the best execution mode and find a trade-off between objectives. Also, according to the nature of the project activities, outputs are categorized into desirable (quality) and undesirable (time, cost and environmental impacts) and analyzed based on the DEA model. In order to rank efficient execution modes, the ideal and anti-ideal virtual units method is used. The proposed model is implemented on a real case of a rural water supply construction project to demonstrate its validity.FindingsThe findings show that the use of the efficient execution mode in each activity leads to an optimal trade-off between the four project objectives (time, cost, quality and environmental impacts).Practical implicationsThis study help project managers and practitioners with choosing the most efficient execution modes of project activities taking time–cost-quality-environmental impacts into account.Originality/valueIn this paper, in addition to time and cost optimization of construction projects, quality factors and environmental impacts are considered. Further to the authors' knowledge, there is no method for evaluating project activities' efficiency. The efficiency of different activity modes is also evaluated for the first time to select the most efficient modes. This research can assist project managers with choosing the most appropriate execution modes for the activities to ultimately accomplish the project with the lowest time, cost and environmental impacts along with the highest quality.

scholarly journals COST OPTIMIZATION OF MULTIUNIT CONSTRUCTION PROJECTS USING LINEAR PROGRAMMING AND METAHEURISTIC-BASED SIMULATED ANNEALING ALGORITHM

2019 ◽  
Vol 25 (8) ◽  
pp. 848-857
Author(s):  
Michał Podolski ◽  
Bartłomiej Sroka
Keyword(s):  
Simulated Annealing ◽  
Optimization Model ◽  
Construction Projects ◽  
Simulated Annealing Algorithm ◽  
High Efficiency ◽  
Programming Model ◽  
Work Group ◽  
Cost Optimization ◽  
Indirect Costs ◽  
Engineering Structures

The article presents the cost optimization model for multiunit construction projects. Multiunit projects constitute a special case of repetitive projects. They consist in the realization of many different, when it comes to size, types of residential, commercial, industrial buildings or engineering structures. Due to the specific character of construction works, actual schedules of such projects should not only take into account real costs of construction, but also be subject to specific restrictions, e.g. deadlines for the completion of units imposed by the investor. To solve the NP-hard problem of choosing the order of units’ construction there was metaheuristic algorithm of simulated annealing used. The objective function in the presented optimization model was the total value of the project cost determined on the basis of the mathematical programming model, taking into account direct and indirect costs, costs of missing deadlines and costs of work group discontinuities. In the article, an experimental analysis of the proposed method of solving the optimization task was carried out in a model that showed high efficiency in obtaining suboptimal solutions. In addition, the operation of the proposed model has been presented on a calculation example. The results obtained in it are fully satisfying.

Sign in / Sign up

Export Citation Format

Share Document