Sharif Digital Repository

Soft computing consists of a set of powerful methods that have been successfully applied to many different application domains, including business, engineering, and bioinformatics. In this research we propose an innovative approach that uses genetic algorithms to mine a set of behavior data output by a biological system in order to determine the kinetic parameters of the system. In our approach, the machine learning method is integrated with the framework of existent biological information in a wiring diagram so that its findings are expressed in a form of system dynamic behavior. An application of the method to the cell division cycle model has shown that the method can discover optimum... 

This research investigates permutation flow shop scheduling problems with sequence-dependent setup times with minimizing the number of tardy jobs as criterion (Fm|prmu, Sijk|ΣUj). A mixed integer linear programming model has been developed for the research problem. As the problem is shown to be NP-hard, several meta-heuristic algorithms based on tabu search (TS) and imperialist competitive algorithm are developed to heuristically solve the problem. In order to find the best meta-heuristic algorithm, random test problems, ranging in size from small, medium, to large are created and solved by the meta-heuristic algorithms. Then, a detailed statistical experiment, based on split-plot design is... 

Sports scheduling with its interesting theory and application has been the subject of many research recently. Different problems arise from different league structures with different objectives. Inspired by the structure of soccer leagues in Britain and Netherlands, we study structures in which a different permutation of first half-season rounds is played during second half-season. Some leagues like Premier league in addition to this structure have a special property in which two teams may do not play against each other in the first half-season and play twice in the second half-season. Therefore, we study both structures separately. We present a mathematical model to cover both structures.... 

This research considers coordination of pricing and scheduling decisions in a make-to-order environment. We consider a two machine flowshop environment. The objective is to maximize the total net profit, i.e. revenue minus scheduling cost resulting from pricing and scheduling decisions. Prices of orders are set by the manufacturer and demand is a non-increasing function of price. Two mixed integer linear programming models have been developed for the research problem. As the problem is shown to be NP-Hard, a Metaheuristic algorithm is developed which is combination of two tabu search sub algorithms, one for pricing and the other for scheduling. And to evaluate performance, results from... 

In this thesis, we consider the problem of scheduling parallel batching machines with different machine capacity and jobs of arbitrary sizes and processing times. The machines have identical processing velocity. The jobs are processed in batches given that the total size of jobs in a batch cannot exceed the machine capacity. Once a batch starts processing, no interruption is allowed until all the jobs are completed. First we present a mixed integer programming model of the problem. We show the computational complexity of the problem, and then we propose two heuristics, LPT-BF and LPT-FF with regard to constraints of problem. Finally, we generate different scales of instances to test the... 

Diabetes has become the most prevalent disease all among the world. One of the complications of this disease is diabetic nephropathy. Diabetic nephropathy occurs when the kidney cells encounter high glucose concentration for long periods. Kidney cells use glucose as their energy supply. However, the excess glucose in the diabetics triggers specific gene pathways, gradually leading to diabetic nephropathy. As a result, proteins’ levels and the activity of transcription factors change during the disease progression. Diabetic nephropathy is characterized by excessive deposition of the proteins comprising the extracellular matrix in the mesangium, basement membrane of the glomerulus, and in the... 

Loop heat pipe (LHP) is a two phase heat transfer device that is mostly used in cooling spacecrafts facilities. In this research a novel LHP is studied analytically and its steady state operating characteristics is analyzed in a one dimensional approach with heat transfer and pressure drop correlations. The novel LHP has a new arrangement in evaporator and reservoir configuration in comparison with conventional LHPs, which results in a different energy and fluid flow. In addition, the novel LHP has a new mechanism for acive control of working temperature. In modeling the proposed LHP the fluid and energy flows are first determined, then proper correltaions for calculationg each energy flow... 

A Loop heat pipe (LHP) is an efficient two phase heat transfer device that is widely used in cooling applications. In this research a novel LHP was designed, fabricated and its performance was investigated through various experiments. The novel LHP has a new arrangement in evaporator and reservoir configuration in comparison with conventional LHPs, which results in a different energy and fluid flow. In addition, the novel LHP has a new mechanism for active control of working temperature which was not already used. Aside from its good performance, this LHP has easier and lower cost manufacturing process compared with the conventional ones. Also the proposed temperature control method is... 

Control of the product manufacturing and evaluating its behavior during deformation is one of the most important issues in hot deformation, especially hot rolling. One of the factors affecting on quality of hot rolled steel strips is the flatness after run-out table cooling.Distortion in a steel strip results from non-uniform temperature profile as the strip cools to room temperature. Increase in the rolling velocity and subsequently the cooling rate affect thermal stresses. In this study a mathematical model for prediction of austenite- ferrite phase transition kinetics and thermo-mechanical stresses on the run-out table after hot rolling was developed for low carbon ferrite steels.... 

In this thesis attempted to present practical hydro-aerodynanic model with low computational time and high accuracy for WIG craft with a compound wing, a catamaran hull form and a power augmented ram (PAR) platform at take-off phase. To achieve this innovation, aerodynamic and hudrodynamic model are coupled and dynamic air cushion between demi hull of catamaran under the wing was considered by modeling PAR platform with effect of flap. To validaty the results of hydro-aerodynanic model, two test models were producted and the results of hydro-aerodynanic model are compared with the experimental results that the presented results had good agreement with the experimental results. Influence of... 

The main purpose of this research is to consider the operational machine cost in the shop floor scheduling, which is not considered in the literature thoroughly. To this end, four types of problems in the parallel machine environment are studied with the objectives of minimizing makespan and total cost. Accordingly, the problems are as type of multi-objective optimization, so we choose the approach of finding Pareto optimal solutions to solve them. In these problems we have considered unrelated parallel machines, uniform parallel machines, and the cases of existence or non-existence of sequence dependent setup times and costs. In order to solve the problems, various approaches, with respect... 

In most of the commercial and academic multiphase flow simulators, the numerical method in use is based on finite difference methods which can lead the solution toward numerical dispersions or even oscillations. These methods are very sensitive to the size of computational grid blocks. Even if we change the numerical method from finite difference to linear finite element (hFEM), still there will be such problems and size of grid blocks will be crucial in getting proper results which can lead to millions of computational grid blocks. One way to deal with this problem is using nonlinear finite element methods (pFEM) also known as higher-order finite element methods, Also compositional... 

In the aftermath of earthquakes, hospitals serve the critical role of treating casualties and reducing mortalities and severe injuries. A hospital must be resilient to play its role correctly after the earthquake. A resilient hospital is able to maintain its functionality at an acceptable level and provide service to the injured. In order to enhance the resilience of a hospital, an appropriate framework is needed to evaluate the hospital resilience and determines the impact of modification actions. This framework should characterize the serviceability of a hospital in terms of an appropriate metric. In this framework, the behavior of a given hospital building in the event of an earthquake as... 

In this study, DREAM model operation as a model to predict the occurrence of dust storms has been completed. The aim of this study is to identify capability of the model to predict dust storms in IRAN. The model has been run for June 2014 because on 2 June 2014, Tehran visited a dust storm with a speed of 111 kilometers per hour and yielded a huge economic losse. In this model, dust concentration,dust load and Aerosol Optical Depth(AOD) are calculated on an hourly basis. The model results do not captured the direct relationship between the average wind speed and dust Parameters and the model do not predict the dust storm on on 2 June 2014 in Tehran. The reason is that DREAM gets... 

Recently, reducing greenhouse gas emissions and the damage to the environment is very important. Due to the increasing environmental awareness of the people on the one hand, and government pressure to reduce damage to the environment on the other hand, has led organizations to pay more attention to this important issue. In addition, these organizations in order to participate in the global competition, should consider green criteria along with other criteria. Hence, the organizations to outsourcing part of their work are looking for Suppliers who along with other criteria also meet the criteria for being green. In this study, a new two-stage approach based on fuzzy... 

In this study a mathematical model for intravitreal injection and depositing controlled release systems in the eye to treat posterior segment deseases is developed. The effects of important parameters that play a critical role in drug distribution are also studied.
Geometrical model is constructed using COMSOL software and governing equations for a 3-D model of drug distribution are solved by finite element method. The geometry is based on the exact dimensions of human eye and retina, choroid and sclera are considered separately. Choroidal losses to the circulatory system and active transport by the retinal pigment epithelium are incorporated as well. Moreover, two types of implant... 

This thesis deals with credit derivatives modeling and consists of two parts:The first part concerns the density model, recently proposed by El Karoui et al. [46], where the standing assumption is that the conditional law of default time given the reference filtration is equivalent to its (non-conditional) law. Under this assumption, we provide alternative (and simpler) proofs for some existing results in the theory of initial and progressive enlargement of filtrations. Also, we present some new results such as the predictable representation theorem for progressively enlarged filtration in the multidimensional case. We then propose several methods to construct density models, in both... 

An industrial scale reactor for light olefinsproduction was modelledusing the oxidative dehydrogenation (ODH) of light paraffinsin a multi-tubular reactor system involving 10000 small diameter tubes immersed in a shell with proper liquid-cooled flows. Here a theory-based pseudo-homogeneous 1-D model describing the operation of a fixed bed reactor for the ODHparaffinstoolefins over a Ni-Nb-O mixed oxide catalyst (for ethane) and over a V2O5/γ-Al2O3catalyst (for Propane),was employed. The paraffin and oxygen conversions, gas process and coolant temperatures, as well as other parameters affecting the reactor performance, including pressure, were examined. Furthermore, the applied model showed... 

In this research, a mathematical model was developed to simulate a two-phase fluidized bed reactor for oxidative dehydrogenation of propane to propylene. Since the assumption of minimum fluidization condition for the emulsion phase is not realistic , the hydrodynamic structure proposed by Cui et al. was used in this study. The mass balances in unsteady state was obtained in a control volume. The differential equations contain three terms, corresponding to the mass transfer by convection, the exchange between phases and the reaction. All differential equations based upon material balances, hydrodynamics and kinetics for all components were solved numerically using MATLAB software 2010a.... 

The in vivo cell culture process as the main part of tissue engineering was investigated through mathematical modelling and computational fluid dynamic (CFD) simulation of cartilage cell growth. Simulations can provideprocess insights for defining the optimum conditions in order to reach higher culture efficiency. In the mathematical modelling of the cell growth, it was intended to consider the most influencing factors such as biomass concentration, volume fraction, glucose concentration and shear stress levels. These results can be obtained mathematically by solving a set of partial differential equations coupling the glucose concentration, the velocity field and cell growth with each other....