Operations Research
M. Rabbani; S. Aghamohamadi; H. Farrokhi-Asl; M. Alavi mofrad
Abstract
In this paper, a new multi-objective time-cost constrained resource availability cost problem is proposed. The mathematical model is aimed to minimize resource availability cost by considering net present value of resource prices in order to evaluate the economic aspects of project to maximize the quality ...
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In this paper, a new multi-objective time-cost constrained resource availability cost problem is proposed. The mathematical model is aimed to minimize resource availability cost by considering net present value of resource prices in order to evaluate the economic aspects of project to maximize the quality of project's resources to satisfy the expectations of stakeholders and to minimize the variation of resource usage during project. Since the problem is NP-hard, to deal with the problem a simulated annealing approach is applied, also to validate our results GAMS software is used in small size test problems. Due to the dependency of SA algorithm to its initial parameters a taghuchi method is used to find the best possible SA parameters combinations to reach near optimum solutions in large size problems.
Engineering Optimization
K. Chitra; P. Halder
Abstract
In today’s competitive environment completing a project within time and budget, is very challenging task for the project managers. This aim of this study is to develop a model that finds a proper trade-off between time and cost to expedite the execution process. Critical path method (CPM) is used ...
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In today’s competitive environment completing a project within time and budget, is very challenging task for the project managers. This aim of this study is to develop a model that finds a proper trade-off between time and cost to expedite the execution process. Critical path method (CPM) is used to determine the longest duration and cost required for completing the project and then the time-cost trade–off problem (TCTP) is formulated as a linear programming model. Here, LINDO program is used to determine the solution of the model. To implement the proposed model, necessary data were collected through interviews and direct discussion with the project managers of Chowdhury Construction Company, Dhaka, Bangladesh. The analysis reveals that through proper scheduling of all activities, the project can be completed within 120 days from estimated duration of 140 days. Reduction of project duration by 17% is achieved by increasing cost by 3.73%, which is satisfactory.
Fuzzy optimization
S. K. Das
Abstract
The Fuzzy Linear Programming problem has been used as an important planning tool for the different disciplines such as engineering, business, finance, economics, etc. In this paper, we proposed a modified algorithm to find the fuzzy optimal solution of fully fuzzy linear programming problems with equality ...
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The Fuzzy Linear Programming problem has been used as an important planning tool for the different disciplines such as engineering, business, finance, economics, etc. In this paper, we proposed a modified algorithm to find the fuzzy optimal solution of fully fuzzy linear programming problems with equality constraints. Recently, Ezzati et al. (Applied Mathematical Modelling, 39 (2015) 3183-3193) suggested a new algorithm to solve fully fuzzy linear programming problems. In this paper, we modified this algorithm and compare it with other existing methods. Furthermore, for illustration, some numerical examples and one real problem are used to demonstrate the correctness and usefulness of the proposed method.
Engineering Optimization
A. H. Niknamfar; H. Esmaeili
Abstract
Nanotechnology deals with studies of phenomena and manipulation on elements of matter at the atomic, molecular and macromolecular level (rangefrom1to100nm), where the properties of matter are significantly different from properties at larger scales of dimensions. Nanotechnology is science, engineering, ...
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Nanotechnology deals with studies of phenomena and manipulation on elements of matter at the atomic, molecular and macromolecular level (rangefrom1to100nm), where the properties of matter are significantly different from properties at larger scales of dimensions. Nanotechnology is science, engineering, and technology conducted at the nanoscale, which is about 1 to 100 nm where nano denotes the scale range of 10-9 and nanotechnology refers the properties of atoms and molecules measuring thoroughly 0.1 to 1000 nm. Nanotechnology is highly interdisciplinary as a field, and it requires knowledge drawn from a variety of scientific and engineering arenas. There are two main types of approaches to nanotechnology: the first approach is Top-down and another one is Bottom-up approach. The Top-down approach involves taking layer structures that are either reduced down size until they reach the nano-scale or deacon structured into their composite parts. This paper aims to deal with Top-down approach in order to utilize Biopolymer nanoparticles for Creating Antimicrobial for chicken feed so that the live average time of chicken will be increased noticeably by using max-min optimization approach. Finally, the applicability of the proposed approach and the solution methodologies are demonstrated in three steps.
Operations Research
M. A. Abdel Khalek; F. I. El-Hosiny; K. A. Selim; I. Osama
Abstract
A novel continuous electroflotation cell, about 0.6 liter volume capacity, using aluminum electrodes was designed for oil produced water treatment. The treating performance of a novel continuous electroflotation cell for oil produced water was investigated. The pH, current density, and feed water flow ...
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A novel continuous electroflotation cell, about 0.6 liter volume capacity, using aluminum electrodes was designed for oil produced water treatment. The treating performance of a novel continuous electroflotation cell for oil produced water was investigated. The pH, current density, and feed water flow rate as affecting parameters of electroflotation process were studied. The results show that the removal efficiency decreased with increasing feed flow rate. However, it increased with increasing current density. The AC current was preferred because DC current causes passivation of the anode with time. The maximum removal for all types of pollutants is achieved at pH6. The designed electroflotation cell could remove different constituents of oil produced water with range 87.5 - 99.5 % at 25°C, 5V, pH7 and AC current density of 80A/m2 through a bipolar connection of the 8 electrodes with feed water flow rate of 60ml/min (3.6l/hr). The energy consumption was about 1.38Kwh/m3 and the operating cost (cost/m3) was about 0.3US$/m3 for the produced water treatment.
Numerical Analysis
F. Rahpeymaii; M. Kimiaei
Abstract
In this paper, we introduce a new adaptive trust-region approach to solve systems of nonlinear equations. In order to improve the efficiency of adaptive radius strategy proposed by Esmaeili and Kimiaei [8], Barzilai Borwein technique (BB) [3] with low memory is used which can truly control the trust-region ...
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In this paper, we introduce a new adaptive trust-region approach to solve systems of nonlinear equations. In order to improve the efficiency of adaptive radius strategy proposed by Esmaeili and Kimiaei [8], Barzilai Borwein technique (BB) [3] with low memory is used which can truly control the trust-region radius. In addition, the global convergence of the new approach is proved. Computational experience suggests that the new approach is more effective in practice in comparison with other adaptive trust-region algorithms.
Numerical Analysis
R. Ezzati; K. Maleknejad; E. Fathizadeh
Abstract
In this paper we use a computational method based on CAS wavelets for solving nonlinear fractional order Volterra integral equations. We solve particularly Abel equations. An operational matrix of fractional order integration for CAS wavelets is used. Block Pulse Functions (BPFs) and collocation method ...
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In this paper we use a computational method based on CAS wavelets for solving nonlinear fractional order Volterra integral equations. We solve particularly Abel equations. An operational matrix of fractional order integration for CAS wavelets is used. Block Pulse Functions (BPFs) and collocation method are employed to derive a general procedure for forming this matrix. The error analysis of proposed numerical scheme is studied theoretically. Finally, comparison of numerical results with exact solution are shown.
