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    Total completion time minimisation of no-wait flowshop group scheduling problem with sequence dependent setup times

    , Article European Journal of Industrial Engineering ; Volume 11, Issue 1 , 2017 , Pages 22-48 ; 17515254 (ISSN) Behjat, S ; Salmasi, N ; Sharif University of Technology
    Inderscience Enterprises Ltd  2017
    Abstract
    In this research, the no-wait flowshop sequence dependent group scheduling problem with minimisation of total completion time, noted as Fm|nwt, fmls, Splk|∑Cj is approached. A mixed integer linear mathematical model is proposed for the research problem. Due to the NP-hard nature of the proposed problem, several metaheuristic algorithms based on particle swarm optimisation and variable neighbourhood search with different neighbourhood search structures are proposed to heuristically solve the problem. Also, an efficient heuristic algorithm is proposed to generate the initial feasible solutions for the proposed algorithms. The performances of the proposed algorithms are compared with each other... 

    Group Scheduling on Flow Shop with Sequence Dependent Setup Times and no Wait Assumption

    , M.Sc. Thesis Sharif University of Technology Behjat, Saeed (Author) ; Salmasi, Naser (Supervisor)
    Abstract
    The present thesis is focused upon the flow shop sequence dependent group scheduling problem (FSDGS) with no wait assumption. Generally, production sequencing and scheduling is considered as one of the most important factors in productivity and cost saving of organizations. Therefore, determining an appropriate sequencing of groups and jobs according to the logical constraints is expected to improve the performance and productivity of the production system.
    In this thesis, due to the importance and multiple applications of this problem, we will consider the FSDGS problem and propose new heuristic and metaheuristic algorithms to tackle this problem. Since the good performance of... 

    Praparation of Nanometric Platinum Coatings on Carbon Substrate (Pt/C) for Catalytic Plates of Fuel Cells

    , M.Sc. Thesis Sharif University of Technology Behjat, Saeed (Author) ; Ghorbani , Mohammad (Supervisor) ; Afshar, Abdollah (Supervisor)
    Abstract
    With increasing pollution and decrease in global reservoirs of fossil fuels, a lot of interest has been attracted to fuel cells as efficient and clean energy sources. Polymeric (membrane) fuel cells are special type of fuel cells, which can be built in small dimensions and power. These cells use hydrogen (and oxygen or air) and produce water. In these cells, platinum is used as electrode (and electrocatalyst) both in anode and cathode, due to its low overvoltage for both hydrogen and oxygen. To increase the efficiency of these coatings, it is best to produce platinum particles with maximum area and it automatically leads to nanometric particles. In this thesis, platinum particles are... 

    Design and Fabrication of a Balance Training Apparatus

    , M.Sc. Thesis Sharif University of Technology Behjat, Amir (Author) ; Behzadipour, Saeed (Supervisor) ; Farahmand, Farzam (Co-Advisor)
    Abstract
    One of the main reasons of being unable in doing routine jobs is the disability to attain and keep balance. This ability can be restored using rehabilitation techniques. A physiotherapist can be very helpful. This approach, however, apart from being very time consuming and expensive, needs quite a few physiotherapists. The physiotherapist will be prone to physical damages as well. This leads to improving therapy methods which do not require a physiotherapist. Using the rehabilitation balance devices can help solve the problem to some extents. If good device with reliable value system be developed, this device can be used without physiotherapist.
    This project has been carried out to... 

    Experimental Investigation and CFD Simulation of the Flow Pattern of the FCC's Fluidized Bed Regenerator

    , M.Sc. Thesis Sharif University of Technology Azarnivand, Abbas (Author) ; Dehkordi, Asghar Molaei (Supervisor) ; Seifkordi, Aliakbar (Supervisor) ; Behjat, Yaghoub (Supervisor)
    Abstract
    Hydrodynamic behavior of gas-solid fluidization in large-diameter beds like FCC regenerator exhibits complex aspects. To investigate the gas-solid flow pattern of UOP's combustor-style FCC regenerator, a lab-scale regenerator was designed by a downscale factor of 0.045. The regenerator's operation and fluidization of FCC particles through it was examined and pressure axial distributions were measured and analyzed at different superficial air velocities. 3D CFD simulation of the regenerator was performed with Eulerian-Eulerian approach to investigate the effects of operating conditions, including superficial air velocity, catalyst mass flux, presence of recirculated catalyst, and the... 

    A general model for I/O system theory, Proceedings of AIMC31 [electronic resource]

    , Article Iranian Journal of Fuzzy Systems ; 2006, Volume 3, Issue 2, Page 1-19 Daneshgar, A. (Amir) ; Hashem, Amir ; Sharif University of Technology

    Experimental and Numerical Study of Spray Combustion under Hot-diluted Conditions

    , M.Sc. Thesis Sharif University of Technology Azimi, Amir Hossein (Author) ; Mardani, Amir (Supervisor)
    Abstract
    In this thesis, combustion of liquid fuel spray under the condition of hot and diluted oxidizer, has been investigated. To this end, a novel type laboratory-scale test rig was designed to study the physics governing the MILD-Spray combustion conditions with an applied approach. The underlined test rig eliminates the operational problems of its predecessor test stands and is used for a heavier fuel with much more complex chemical composition (kerosene). The test section is axially symmetrical, in which the fuel is injected by a pressure-swirl atomizer in the direction of hot and diluted co-flowing air. With the use of the aforesaid test rig, the effect of variables such as oxygen... 

    General theory of translation invariant systems [electronic resource]

    , Article Mathematics and Its Applications ; Volume 329, 1995, pp 77-89 Daneshgar, A. (Amir) ; Sharif University of Technology
    Abstract
    The basic goal of this article is to present an abstract system-theoretic approach to morphological filtering and the theory of translation invariant systems which is mainly based on residuated semigroups. Some new results as well as a number of basic questions are also introduced  

    Duality in a generalized model for translation invariant systems [electronic resource]

    , Article Fuzzy Sets and Systems ; 1996, Volume 83, Issue 3, Pages 347–352 Daneshgar, A. (Amir) ; Sharif University of Technology
    Abstract
    In a previous paper we introduced a generalized model for translation invariant (TI) operators. In this model we considered the space, φ of all maps from an abelian group G to ω U {-∞}, called LG-fuzzy sets, where ω is a complete lattice-ordered group; and we defined TI operators on this space. Also, in that paper, we proved strong reconstruction theorem to show the consistency of this model. This theorem states that for an order-preserving TI operator Y one can explicitly compute Y(A), for any A, from a specific subset of φ called the base of Y. In this paper duality is considered in the same general framework, and in this regard, continuous TI operators are studied. This kind of operators... 

    Reconstruction in a generalized model for translation invariant systems [electronic resource]

    , Article Fuzzy Sets and Systems ; 1996, Volume 83, Issue 1, Pages 51–55 Daneshgar, A. (Amir) ; Sharif University of Technology
    Abstract
    We consider translation invariant (TI) operators on Φ, the set of maps from an abelian group G to Ω ∪ {−∞} , called LG-fuzzy sets, where 0 is a complete lattice ordered group. By defining Minkowski and morphological operations on Φ and considering order preserving operators, we prove a reconstruction theorem. This theorem, which is called the Strong Reconstruction Theorem (SRT), is similar to the Convolution Theorem in the theory of linear and shift invariant systems and states that for an order preserving TI operator Y one can explicitly compute Y ( A ), for any A , from a specific subset of Φ called the base of Y . The introduced framework is a general model for the theory of translation... 

    Residuated semigroups and morphological aspects of translation invariant systems [electronic resource]

    , Article 1997, Volume 90, Issue 1, Pages 69–81 ; Fuzzy Sets and Systems Daneshgar, A. (Amir) ; Sharif University of Technology
    Abstract
    The main goal of this paper is to verify classical properties of morphological operators within the general model of translation invariant (TI) systems. In this model, TI operators are defined on the space of LG-fuzzy sets Φ i.e. Φ = {A: G → Ω ∪ {− ∞}} in which G is an abelian group and Ω is a complete lattice ordered group. A TI operator Y is an operator on Φ which is invariant under translation on G and Ω as groups. We consider the generalization of Minkowski addition (D on Φ and we emphasize that (Φ,⊛) is an involutive residuated topological monoid. We verify all properties of traditional (set-theoretic) morphological operators as well as classical representations (Matheron, 1967) for... 

    Forcing structures and cliques in uniquely vertex colorable graphs [electronic resource]

    , Article SIAM Journal on Discrete Mathematics ; 2001, Volume 14, Issue 4, Pages 433-445 Daneshgar, A. (Amir) ; Sharif University of Technology
    Abstract
    Let G be a simple undirected uniquely vertex k-colorable graph, or a k-UCG for short. M. Truszczyński [Some results on uniquely colorable graphs, in Finite and Infinite Sets, North-Holland, Amsterdam, 1984, pp. 733--748] introduced $e^{^{*}}(G)=|V(G)|(k-1)-{k \choose 2}$ as the minimum number of edges for a k-UCG and S. J. Xu [J. Combin. Theory Ser. B, 50 (1990), pp. 319--320] conjectured that any minimal k-UCG contains a Kk as a subgraph. In this paper, first we introduce a technique called forcing. Then by applying this technique in conjunction with a feedback structure we construct a k-UCG with clique number k-t, for each $t \geq 1$ and each k, when k is large enough. This also... 

    Graph homomorphisms and nodal domains [electronic resource]

    , Article Linear Algebra and its Applications ; 2006, Volume 418, Issue 1, Pages 44–52 Daneshgar, A. (Amir) ; Sharif University of Technology
    Abstract
    In this paper, we derive some necessary spectral conditions for the existence of graph homomorphisms in which we also consider some parameters related to the corresponding eigenspaces such as nodal domains. In this approach, we consider the combinatorial Laplacian and co-Laplacian as well as the adjacency matrix. Also, we present some applications in graph decompositions where we prove a general version of Fisher’s inequality for G-designs  

    On defining numbers of circular complete graphs

    , Article Discrete Mathematics ; Volume 307, Issue 2, 28 January 2007, Pages 173–180 Daneshgar, A. (Amir) ; Sharif University of Technology
    Abstract
    Let d(σ)d(σ) stand for the defining number of the colouring σσ. In this paper we consider View the MathML sourcedmin=minγd(γ) and View the MathML sourcedmax=maxγd(γ) for the onto χχ-colourings γγ of the circular complete graph Kn,dKn,d. In this regard we obtain a lower bound for dmin(Kn,d)dmin(Kn,d) and we also prove that this parameter is asymptotically equal to χ-1χ-1. Also, we show that when χ⩾4χ⩾4 and s≠0s≠0 then dmax(Kχd-s,d)=χ+2s-3dmax(Kχd-s,d)=χ+2s-3, and, moreover, we prove an inequality relating this parameter to the circular chromatic number for any graph G  

    Modeling Driving Behaviors Using Smartphone Sensors

    , M.Sc. Thesis Sharif University of Technology Azizzadeh Delshad, Amir Hossein (Author) ; Samimi, Amir (Supervisor)
    Abstract
    Monitoring driving behaviors of drivers, would avoid their dangerous behaviors and remarkably raise the safety. Nowadays real-time supervision is considered as one of the modern methods of controlling driving behaviors. Previously, due to expensive costs of required equipments and other restrictions, this kind of supervision hasn't been considered fairly. Nowadays increasing usage of smart phones, which contain multiple sensors, enables this type of supervision with lower costs. In the present study we would present some models, to assess the driving behavior via smart phone sensors such as accelerometer, gyroscope and rotation vector  

    Crack Propagation Modeling in Arched Concrete Structures Reinforced by FRP Using XFEM and Damage Model

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Amir Hossein (Author) ; Khoei, Amir Reza (Supervisor)
    Abstract
    In practice, structures made of concrete are full of cracks. The strength of concrete is mainly determined by the tensile strength, which is about 10% of the compressive strength. As long as cracking in concrete is unavoidable, we have to try to minimize their detrimental effects. This objective can be achieved by resisting (or limiting) propagation of existing cracks. Because of this, reinforcement (mostly steel) is used to increase the carrying capacity of the material and to control the development of cracks. Concrete structures that fail, already shows a large number of large and small cracks before their maximum carrying capacity is reached. The failure of concrete can be characterized... 

    Structural Health Monitoring Using Optimal Finite Element Model Based on Digital Image Correlation

    , M.Sc. Thesis Sharif University of Technology Amir Hossein Amir Ahmadi (Author) ; Khaloo, Alireza (Supervisor)
    Abstract
    The purpose of this research is to monitor the health of structures using the updated finite element model, in which digital images are used to optimize the numerical model. Structural Health Monitoring (SHM) is always an important and significant issue that has attracted the attention of many researchers in recent years. In general, some researches have been conducted in this field using physical sensors that provide discrete data to the system for analysis. Using cameras to monitor the structure makes it possible to extract continuous and integrated data from the structure using digital images, which is a significant advantage compared to physical sensors.In this research, a steel... 

    Finite Size Effect in SLE(k,p)

    , M.Sc. Thesis Sharif University of Technology Amir Bagheri, Amir Ali (Author) ; Moghimi Araghi, Saman (Supervisor)
    Abstract
    Conformal Field Theory provides an efficient method for studying physical problems in critical point. Correlation length becomes converge in this point. It can also be clarified that some curves are observed in geometrical phase transition which are conformal invariant and they can be studied using SLE(k). The first mathematical generalization of SLE(k) while keeping the self-similarity property, leads to SLE(k,p). Conformal field theory and SLE are interrelated and their parameters are interpretable for each other. One usually studies the problem in the upper-half plane. Here we consider the problem using a map like (w=L/π Ln z) between the upper-half plane and a special region (e.g. a... 

    On small uniquely vertex-colourable graphs and Xu's conjecture [electronic resource]

    , Article Discrete Mathematics ; Volume 223, Issues 1–3, 28 August 2000, Pages 93–108 Daneshgar, A. (Amir) ; Naserasr, Reza ; Sharif University of Technology
    Abstract
    Consider the parameter Λ(G) = |E(G)| - |V(G)|(k - 1) + (k2) for a k-chromatic graph G, on the set of vertices V(G) and with the set of edges E(G). It is known that Λ(G)≥0 for any k-chromatic uniquely vertex-colourable graph G (k-UCG), and, S.J. Xu has conjectured that for any k-UCG, G, Λ(G) = 0 implies that cl(G) = k; in which cl(G) is the clique number of G. In this paper, first, we introduce the concept of the core of a k-UCG as an induced subgraph without any colour-class of size one, and without any vertex of degree k - 1. Considering (k, n)-cores as k-UCGs on n vertices, we show that edge-minimal (k, 2k)-cores do not exist when k ≥ 3, which shows that for any edge-minimal k-UCG on 2k... 

    Graph homomorphisms through random walks [electronic resource]

    , Article Journal of Graph Theory ; 2003, Volume 44, Issue 1, pages 15–38 Daneshgar, A. (Amir) ; Hajiabolhassan, Hossein ; Sharif University of Technology
    Abstract
    In this paper we introduce some general necessary conditions for the existence of graph homomorphisms, which hold in both directed and undirected cases. Our method is a combination of Diaconis and Saloff–Coste comparison technique for Markov chains and a generalization of Haemers interlacing theorem. As some applications, we obtain a necessary condition for the spanning subgraph problem, which also provides a generalization of a theorem of Mohar (1992) as a necessary condition for Hamiltonicity. In particular, in the case that the range is a Cayley graph or an edge-transitive graph, we obtain theorems with a corollary about the existence of homomorphisms to cycles. This, specially, provides...