scholarly journals Multi-objective optimization of time-cost-quality in construction projects using genetic algorithm

2020 ◽  
Vol 19 (3) ◽  
pp. 335-346
Author(s):  
Cemil Akcay ◽  
◽  
Setenay Işikyildiz ◽  

In this study, it was aimed to develop a model that provides Time-Cost-Quality optimization in construction projects using Genetic algorithm method. In order to fulfill that, Matlab codes for a multi-purpose genetic algorithm that performs Time-Cost-Quality optimization were developed and applied to the problem, and the targeted success level was substantially achieved. This model is capable of performing and visualizing an advanced three-dimensional time, cost, quality tradeoff analysis instead of the traditional two-dimensional time-cost tradeoff analysis. It was possible to select the desired alternative under the project conditions obtaining pareto images called a set of solutions rather than a single solution. In addition, one of the main objectives of this study is to develop an effective model to assist the main contractors of the construction in selecting the most suitable subcontractors.

Author(s):  
M. Himeno ◽  
S. Noda ◽  
R. Himeno ◽  
K. Fukasaku

We used the genetic algorithm (GA) and two-dimensional blood flow analysis to examine the fluid dynamic and engineering factors in multi-objective optimization of blood tubes (vessels). We supposed two factors from fluid dynamics: the wall shear stress (WSS) and the pressure loss, and one materials saving factor: the artery length. As a result, we could get the optimum shapes for each factor. In the case of WSS and artery length, both smoothly curved artery shapes and shapes with bulges were obtained as lower WSS cases. The shapes with bulges were similar to those of aneurysms. In this case, it was found that the WSS increases after the bulge is removed. This means bulges in artery vessel areas with higher WSSs effectively reduce the WSS value. Only the case of WSS and artery length produced a shape like an aneurysm. These results indicate that WSS and artery length are significant factors in determining artery shape.


2016 ◽  
Vol 18 (32) ◽  
pp. 22122-22128 ◽  
Author(s):  
Fernando Buendía ◽  
Jorge A. Vargas ◽  
Marcela R. Beltrán ◽  
Jack B. A. Davis ◽  
Roy L. Johnston

The combined use of a genetic algorithm and Density Functional Theory (DFT) calculations allows us to explore the potential energy surface. Our results show interesting effects on the geometries of the clusters on deposition. Two-dimensional clusters in the gas phase become three-dimensional and vice versa.


2012 ◽  
Vol 433-440 ◽  
pp. 5746-5752 ◽  
Author(s):  
Hadi Mokhtari ◽  
Ali Salmasnia ◽  
Mahdi Bastan

Time, cost and quality are crucial aspects of each project and tradeoff among them is important for improvement of the overall performance of industrial and construction projects. In this paper we suggest that the quality is added into the traditional time-cost trade-off problem (TCTP) and develop a three dimensional time, cost and quality trade-off problem (TCQTP) with some realistic assumptions. To the best of our knowledge this problem has not been extensively treated in literature yet. In order to deal with the suggested stochastic TCQTP, a statistical robust solution method is adapted in which not only the correlations among objectives are considered but also the variance of objectives is minimized. A computational study on an illustrative example is done and the results support the applicability and reliability of the suggested model.


Author(s):  
Ashish Sharma

Abstract: In every construction project, the time and cost are the two most important objectives/factors to be considered. Clients and contractors should strive to optimize the project time and cost to maximize the return. Resources are also one of the major constraints of the construction projects. In recent years, several studies have been conducted to optimize the time and cost of project under constraint conditions of resources. Since most studies assume the time and cost as deterministic parameters, uncertainties should be considered in estimating the time and cost of the project's activities when minimizing the duration and cost of the project. For this purpose, this paper embeds the fuzzy logic to handle the uncertainties in estimating the time and cost. Besides, the multi-objective genetic algorithm (MOGA) is used to develop the resourceconstrained time-cost trade-off model. Alpha-cut approach is utilized to define the accepted risk level of decision maker. The efficiency of the proposed model is demonstrated through solvinga case study project of highway construction. The results of case study project provide a set of Pareto-optimal solutions. The developed model encourage the decision making process by choosing specified risk levels and utilizing the related Pareto-front. Keywords: Construction projects, time-cost trade-off, uncertainties, fuzzy logic, MOGA,Pareto-optimal solution.


2015 ◽  
Vol 22 (4) ◽  
pp. 837-851 ◽  
Author(s):  
Shmuel Vigdergauz

The well-known developments in elastostatics concerning the equi-stressness criterion of optimality for two-dimensional multi-connected unbounded solids under the bulk-dominating load are generalized toward the transient three-dimensional case with rotational symmetry. This paper advances our previous work by focusing specifically on explicitly identifying the optimal equi-stress surfaces through a simple regular integral equation which involves the single-layer potential kernel associated with the axially symmetric Laplacian. Its two-dimensional analogue is also obtained as a competitive counterpart to the commonly used complex-variable formalism. In both cases, the equations are reformulated as a minimization problem, solved numerically with a standard genetic algorithm over a wide variety of governing parameters thus permitting comparison of the shape optimization results in spatial and plane elasticity for multi-connected domains.


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