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A fuzzy random minimum cost network flow programming problem [electronic resource]
, Article Journal of Industrial and Systems Engineering (JISE)-Iranian Institute of Industrial Engineering ; Article 3, Volume 6, Issue 1, Spring 2012, Page 34-47 ; Eshghi, Kourosh ; Sharif University of Technology
Abstract
In this paper, a fuzzy random minimum cost flow problem is presented. In this problem, cost parameters and decision variables are fuzzy random variables and fuzzy numbers respectively. The object of the problem is to find optimal flows of a capacitated network. Then, two algorithms are developed to solve the problem based on Er-expected value of fuzzy random variables and chance-constrained programming. Furthermore, the results of two algorithms will be compared. An illustrative example is also provided to clarify the concept
Special classes of mathematical programming models with fuzzy random variables [electronic resource]
, Article Journal of Intelligent and Fuzzy Systems, Published In: IOS Press ; Volume 19, Number 2, 2008 ; Nematian, Javad ; Sharif University of Technology
Abstract
In this paper, we will discuss two special classes of mathematical programming models with fuzzy random variables. In the first model, a linear programming problem with fuzzy decision variables and fuzzy random coefficients is introduced. Then an algorithm is developed to solve the model based on fuzzy optimization method and fuzzy ranking method. In the second model, a fuzzy random quadratic spanning tree problem is presented. Then the proposed problem is formulated and solved by using the scalar expected value of fuzzy random variables. Furthermore, illustrative numerical examples are also given to clarify the methods discussed in this paper
A special class of fuzzy integer programming model with all different constraints [electronic resource]
, Article Scientia Iranica ; Vol. 16, No. 1, pp. 1-10, 2009 ; Nematian, Javad ; Sharif University Of Technology
Abstract
In this paper, a fuzzy approach is applied to special classes of integer programming problems with all diierent constraints. In the rst model, a fuzzy integer programming model is developed to represent the all-diierent constraints in mathematical programming. In order to solve the proposed model, a new branching scheme for the Branch and Bound algorithm is also presented. In the second model, a special class of large-scale multi-objective fuzzy integer programming problems with all-diierent constraints is introduced. A solution method for the proposed model is also developed by using the decomposition technique, weighting method and Branch and Bound algorithm. An illustrative numerical...
Fuzzy random minimum cost network problem [electronic resource]
, Article Journal of Industrial and Systems Engineering ; Vol. 6, No. 1, pp 34-47, 2012 ; Eshghi, Kourosh ; Sharif University of Technology
Abstract
In this paper, a fuzzy random minimum cost flow problem is presented. In this problem, cost parameters and decision variables are fuzzy random variables and fuzzy numbers respectively. The object of the problem is to find optimal flows of a capacitated network. Then, two algorithms are developed to solve the problem based on Er-expected value of fuzzy random variables and chance-constrained programming. Furthermore, the results of two algorithms will be compared. An illustrative example is also provided to clarify the concept
Fuzzy reliability optimization models for redundant systems [electronic resource]
, Article International Journal of Industrial engineering ; July 2008, Vol. 4, No. 7, 1-9 ; Eshghi, Kourosh ; Eshraghniaye Jahromi, Abdolhamid ; Sharif University of Technology
Abstract
In this paper, a special class of redundancy optimization problem with fuzzy random variables is presented. In this model, fuzzy random lifetimes are considered as basic parameters and the Er-expected of system lifetime is used as a major type of system performance. Then a redundancy optimization problem is formulated as a binary integer programming model. Furthermore, illustrative numerical examples are also given to clarify the methods discussed in this paper
A resource constrained project scheduling problem with fuzzy random duration [electronic resource]
, Article Journal of Uncertain Systems ; Vol.4, No.2, pp.123-132, 2010 ; Eshghi, Kourosh ; Eshragh Jahromi, Abdolhamid ; Sharif University of Technology
Abstract
In this paper, first a fuzzy random resource-constrained project scheduling problem is presented. The object of the problem is to find the optimal scheduling of project activities. In this model, duration of project activities is a fuzzy random variable. Then, the proposed model is formulated by using the expected value of fuzzy random variables as an IP model. An illustrative example is also provided to clarify the concept. © 2010 World Academic Press, UK. All rights reserved
Waste Load Allocation in Rivers by Means of the Game Theory Case Study: Dez river
, M.Sc. Thesis Sharif University of Technology ; Abrishamchi, Ahmad (Supervisor) ; Arhami, Mohammad (Supervisor)
Abstract
Nowadays, by development of technology and population, rivers have been faced environmental issues. In one hand, due to the several factors that can affect rivers pollution, it is not easy to propose a comprehensive solution for the above mentioned issues, while, on the other hand, it is necessary to address and resolve some of these issues as soon as possible. Considering rives as a system, there are lots of economic, political and quite a few other factors which try to change the condition to their own interest. In order to find a solution that satisfies all the effective parameters up to a certain limit, a mathematical tool, called the Game theory method, is utilized. In this research, we...
Adsorption of eco-friendly carthamus tinctorius on steel surface in saline solution: a combination of electrochemical and theoretical studies
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 601 , 20 September , 2020 ; Ramazani Saadat Abadi,A ; Mahdavian, M ; Bahlakeh, G ; Haddadi, S. A
Elsevier B.V
2020
Abstract
In this study, the different parts of carthamus tinctorius plant, including petal (SPE), leaf (SLE), and shoot (SSE), have been extracted. Adsorption of the extracts on mild steel in 3.5 wt. % NaCl solution was evaluated employing electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and electrochemical noise measurements (EN). The field-emission scanning electron microscopy (FE-SEM) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) were employed to appraise the morphology of the samples surface subjected to the test solutions. According to the EIS results, the maximum adsorption efficiency belonged to the solution containing 1 g L−1 of...
Probing the Performance of Safflower Plant as a Green Inhibitor with Molybdenum Disulfide on Corrosion Protection Properties of the Epoxy Coating
, M.Sc. Thesis Sharif University of Technology ; Ramazani Saadat Abadi, Ahmad (Supervisor) ; Mahdavian Ahadi, Mohammad (Supervisor)
Abstract
Today, the process of corrosion and compensation of minor injuries, without the need for tracing or any other physical interference, has become one of the subjects of interest to researchers. Inhibitors have been considered as one of the anti-corrosion agents. In this research, safflower extract as a green inhibitor in sodium chloride corrosive environment was used to evaluate the rate of corrosion of mild steel. Also the MoS2 nanoparticles were used as carrier of this green inhibitore in the epoxy coating to allow the activation of the coating in a scratched state in sodium chloride solution of 3.5%. In the first step, the extract of the safflower was prepared to reach the best part of this...
Microwave-induced Cannizzaro reaction over neutral γ-alumina as a polymeric catalyst [electronic resource]
, Article Reactive and Functional Polymers ; 01/2002; 51(1):49-53 ; Soleimanzadeh, B ; Marandi, G. B
Abstract
γ-Alumina is used to catalyze the Cannizzaro reaction in the absence of any base under microwave irradiation in high yields. In the case of terephthalaldehyde the reaction is carried out with high selectivity
SnCl4/SiO2: an efficient heterogeneous alternative for one-pot synthesis of β-acetamidoketones
, Article Journal of the Chinese Chemical Society ; Volume 56, Issue 2 , 2009 , Pages 386-391 ; 00094536 (ISSN) ; Mahmoodi Hashemi, M ; Sadeghi, B ; Emtiazi, H ; Sharif University of Technology
2009
Abstract
Enolizable ketones have been reacted in a one-pot method with aromatic aldehydes, acetyl chloride and acetonitrile at room temperature in the presence of SnCl4/SiO2 to furnish the corresponding β-acetamidoketones in improved yields. Acetylation of an aromatic hydroxyl group was observed while using 4-hydroxybenzaldehyde or vanillin and the corresponding β-acetamidoketones were isolated in an excellent yield
Turbulent flow in converging nozzles, part one: Boundary layer solution
, Article Applied Mathematics and Mechanics (English Edition) ; Volume 32, Issue 5 , 2011 , Pages 645-662 ; 02534827 (ISSN) ; Farhanieh, B ; Firoozabadi, B ; Sharif University of Technology
2011
Abstract
The boundary layer integral method is used to investigate the development of the turbulent swirling flow at the entrance region of a conical nozzle. The governing equations in the spherical coordinate system are simplified with the boundary layer assumptions and integrated through the boundary layer. The resulting sets of differential equations are then solved by the fourth-order Adams predictor-corrector method. The free vortex and uniform velocity profiles are applied for the tangential and axial velocities at the inlet region, respectively. Due to the lack of experimental data for swirling flows in converging nozzles, the developed model is validated against the numerical simulations. The...
Numerical investigation of steady density currents flowing down an incline using v2̄ - F turbulence model
, Article Journal of Fluids Engineering, Transactions of the ASME ; Volume 129, Issue 9 , 2007 , Pages 1172-1178 ; 00982202 (ISSN) ; Firoozabadi, B ; Farhanieh, B ; Sharif University of Technology
2007
Abstract
The governing equations of two-dimensional steady density currents are solved numerically using a finite volume method. The v2̄-f turbulence model, based on standard k - s model, is used for the turbulence closure. In this method, all Reynolds stress equations are replaced with both a transport equation for v2̄ and an elliptic relaxation equation for f, a parameter closely related to the pressure strain redistribution term. The Simple-C procedure is used for pressure-velocity coupling. In addition, Boussinesq's approximation is used to obtain the momentum equation. The computed height of the progressive density current is compared to the measured data in the literature, resulting in good...
Numerical simulation of turbid-density current using v2̄ - f turbulence model
, Article 2005 ASME International Mechanical Engineering Congress and Exposition, IMECE 2005, Orlando, FL, 5 November 2005 through 11 November 2005 ; Volume 261 FED , 2005 , Pages 619-627 ; 08888116 (ISSN); 0791842193 (ISBN); 9780791842195 (ISBN) ; Firoozabadi, B ; Farhanieh, B ; Sharif University of Technology
2005
Abstract
The deposition behavior of fine sediment is an important phenomenon, and yet unclear to engineers concerned about reservoir sedimentation. An elliptic relaxation turbulence model (v2̄ - f model) has been used to simulate the motion of turbid density currents laden whit fine solid particles. During the last few years, the v2̄ - f turbulence model has become increasingly popular due to its ability to account for near-wall damping without use of damping functions. In addition, it has been proved that the v2̄ - f model to be superior to other RANS methods in many fluid flows where complex flow features are present. Due to low Reynolds number turbulence of turbidity current,(its critical Reynolds...
Analytical solution for creeping motion of a viscoelastic drop falling through a Newtonian fluid
, Article Korea Australia Rheology Journal ; Vol. 26, issue. 1 , 2014 , pp. 91-104 ; ISSN: 1226119X ; Norouzi, M ; Firoozabadi, B ; Sharif University of Technology
2014
Abstract
In this paper, an analytical solution for steady creeping motion of viscoelastic drop falling through a viscous Newtonian fluid is presented. The Oldroyd-B model is used as the constitutive equation. The analytical solutions for both interior and exterior flows are obtained using the perturbation method. Deborah number and capillary numbers are considered as the perturbation parameters. The effect of viscoelastic properties on drop shape and motion are studied in detail. The previous empirical studies indicated that unlike the Newtonian creeping drop in which the drop shape is exactly spherical, a dimpled shape appears in viscoelastic drops. It is shown that the results of the present...
Theoretical and experimental study on the motion and shape of viscoelastic falling drops through Newtonian media
, Article Rheologica Acta ; Volume 55, Issue 11-12 , 2016 , Pages 935-955 ; 00354511 (ISSN) ; Norouzi, M ; Firoozabadi, B ; Sharif University of Technology
Springer Verlag
2016
Abstract
In this paper, creeping motion of a viscoelastic drop falling through a Newtonian fluid is investigated experimentally and analytically. A polymeric solution of 0.08 % xanthan gum in 80:20 glycerol/water and silicon oil is implemented as the viscoelastic drop and the bulk viscous fluids, respectively. The shape and motion of falling drops are visualized using a high speed camera. The perturbation technique is employed for both interior and exterior flows, and Deborah and capillary numbers are considered as perturbation parameters up to second order. The product of Deborah and capillary numbers is also used as a perturbation parameter to apply the boundary condition on the deformation on the...
Minimizing uplink delay in delay-sensitive 5G CRAN platforms
, Article 2nd IEEE 5G World Forum, 5GWF 2019, 30 September 2019 through 2 October 2019 ; 2019 , Pages 154-160 ; 9781728136271 (ISBN) ; Kanaanian, B ; Khalaj, B. H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, we consider the problem of minimizing the uplink delays of users in a 5G cellular network. Such cellular network is based on a Cloud Radio Access Network (CRAN) architecture with limited fronthaul capacity, where our goal is to minimize delays of all users through an optimal resource allocation. Earlier works minimize average delay of each user assuming same transmit power for all users. Combining Pareto optimization and Markov Decision Process (MDP), we show that every desired balance in the trade-off among infinite-horizon average-reward delays, is achievable by minimizing a properly weighted sum delays. In addition, we solve the problem in two realistic scenarios;...
Microwave-induced Cannizzaro reaction over neutral γ-alumina as a polymeric catalyst
, Article Reactive and Functional Polymers ; Volume 51, Issue 1 , 2002 , Pages 49-53 ; 13815148 (ISSN) ; Soleimanzadeh, B ; Marandi, G. B ; Sharif University of Technology
2002
Abstract
Microwave induced Cannizzaro reaction, which was performed in presence of neutral γ-alumina as a polymeric catalyst, was discussed. Cannizzaro reaction was carried out on alumina surface and other unknown products were also obtained. Solvent extraction method was utilized to isolate mild and selective benzyl alcohol and carboxylic acids
Feedback bit reduction for antenna selection methods in wireless systems
, Article 2005 13th IEEE International Conference on Networks jointly held with the 2005 7th IEEE Malaysia International Conference on Communications, Kuala Lumpur, 16 November 2005 through 18 November 2005 ; Volume 1 , 2005 , Pages 229-233 ; 1424400007 (ISBN); 9781424400003 (ISBN) ; Babadi, B ; Hossein Khalaj, B ; Sharif University of Technology
2005
Abstract
A well known method to reduce the intrinsic complexity of Multiple Input Multiple Output (MIMO) systems is to choose a subset of available antennas which have stronger links than the others, in order to perform the specified MIMO algorithm. The data resulted from the antenna selection process (at the receiver side) is sent back to the transmitter side via a feedback channel. There seems to be a need to reduce the number of feedack bits, specially when the number of antennas is not small. In this paper, we investigate the problem of reducing the number of feedback bits in antenna selection techniques. We've proposed two methods using vector quantization techniques to perform feedback bit...
A distributed locality-aware neighbor selection algorithm for P2P video streaming over wireless mesh networks
, Article 2012 6th International Symposium on Telecommunications, IST 2012 ; 2012 , Pages 639-643 ; 9781467320733 (ISBN) ; Akbari, B ; Khansari, M ; Ahmadifar, B ; Sharif University of Technology
2012
Abstract
Nowadays, deployment of peer-to-peer video streaming systems over wireless mesh networks has attained raising popularity among large number of users around the world. In this paper, we present an efficient peer-to-peer live video streaming architecture over multi-hop wireless mesh networks. In our proposed architecture, we take the physical topology of network into account and based on a distributed distributed locality-aware neighbor selection algorithm in the overlay construction phase, we generate an efficient mesh-based overlay on top of wireless mesh networks. In locality-aware neighbor selection algorithm, instead of choosing randomly, peers find their best neighbors based on their...