Sharif Digital Repository

Graph sum coloring problem is a special case of graph vertex coloring. Because of its applications in practical areas, especially in scheduling, many researchers have been attracted to it. In recent years, several heuristic and metaheuristic algorithms were applied to sum coloring problem. In this research a heuristic algorithm based on mini-max ant system and simulated annealing metaheuristics is used for graph sum coloring problem. This algorithm is tested on random graphs used in the literature and compared with prior algorithms. Results show that in many cases our proposed algorithm reaches the best known results or improves them  

In this thesis, a fully coupled numerical model is developed for the modeling of the cohesive crack propagation and hydraulic fracturing in porous media using the extended finite element method in conjunction with the cohesive crack model. The governing equations, which account for the coupling between various physical phenomena, are derived within the framework of the generalized Biot theory. The solid phase displacement, the wetting phase pressure and the capillary pressure are taken as the primary variables of the three-phase formulation. The other variables are incorporated into the model via the experimentally determined functions that specify the relationship between the hydraulic... 

The processes of electrochemical water splitting and carbon dioxide reduction are among novel technologies that have gained attention for tackling climate change and global warming. Though, catalysts with fininancial justification for industrial utilization of these processes is still not available. In this study, a 3D-structured electrode of low-carbon 316 stainless steel, made by additive manufacturing, is modified with a trilayered metal-organic framework (MOF), with Iron, Cobalt, and Nickel metallic nodes and BDC-NH2 as the organic ligand, for water splitting. Also, the same steel electrode is modified with a single layered MOF, with Iron node and BDC-NH2 ligand, along with nanoparticles... 

In this work, simulation of 3D three-phase naturally fractured reservoirs is studied. Both Dual Porosity and Dual Porosity-Dual Permeability models which are commonly used in commercial softwares such as ECLIPSE and CMG, are utilized. The governing equations include the mass (in Black-oil model) and linear momentum (in Darcy law form) equations, which are converted into pressure equations and a set of transport equations for the saturations and mole fractions of phases. These equations are solved once for the matrix domain and subsequently for the fracture domain. These two set of equations are coupled through transfer functions. The accuracy of computations significantly depends on how... 

Chemotherapy is a proven and effective systematic approach to treat various types of cancers. Despite its advantages, chemotherapy would kill healthy as well as cancer cells. To overcome this problem, different controlling strategies are implemented. This study aims to provide a medicine drug delivery schedule for chemotherapy (by designing a proper controlling system) based on the verifiable mathematical models. First, the dynamic model is analysed and stability points are reviewed. The selected model has five state variables and two inputs. In this study, the focus is on dynamic model analysis and obtaining an effective and appropriate treatment pattern by designing a proper controller. To... 

Occurrence of natural disasters such as earthquake could seriously damage most buildings especially those with insufficient resistance located in urban worn-out textures. In order to reduce unpleasant consequences of an earthquake, appropriate policies need to be considered to persuade the beneficiaries to follow retrofitting standards in the process of planning, designing, and construction of buildings. These policies shall be implemented through institutions in arbitrary or obligatory forms, by encouragement or penalty mechanisms. In order to consider these policies, first of all we need to identify the beneficiaries and their particulars. By studying and considering subjects discussed in... 

Environmental issues and energy crisis have led the world attention to the renewable energies; especially wind power, since they have low cost and high reliability. One of the most challenging areas of studying for wind power is to increase the capacity of wind turbines. As a result, over the years, wind turbines have got progressively larger. Vibration is one of the problems that reduces the life and efficiency of wind turbines; and the growing size of the blades has worsen this problem due to the importance of nonlinear effects in large scale wind turbines. Researchers have been constantly working on this issue in order to make the wind turbines more efficient. In this research, a...