Sharif Digital Repository

The kidneys serve essential regulatory roles in the body which remove excess organic molecules from the blood and the removal of waste products of metabolism. They are essential in the urinary system. Urinary concentration mechanism has long been interested for mathematicians and physiologists to elucidate the obscurities within the process. In this study, a novel three-dimensional approach is used for simulating urine concentrating mechanism in rat renal medulla. The model equations are based on three spatial dimensions mass and momentum transports. Exact 3D geometry has been designed by using COMSOL Multiphysics software and results have been compared with the latest available data. In... 

The issue of reliability, which is associated with a low probability of error in a communication system, is an important parameter in information theory. By reliability, we mean a low decoding error probability, and one of the main criteria for this is the zero decoding error probability. In the zero-error probability, the decoding error probability for any code is exactly zero. Error-free capacity was examined by Claude Shannon in 1956. The Shannon capacity of a communication channel is defined using the independent sets of strong products of graph. Shannon calculated the capacity of graphs up to five vertices except the graphC5. Lovász, in 1979, using the upper bound he provided, was able... 

3D bioprinting technology is a promising approach for corneal stromal tissue regeneration. At first, two different concentrations of GelMA macromer (7.5% and 12.5%) were tested for corneal stroma bioprinting. Due to high macromer concentrations, 12.5% GelMA was stiffer than 7.5% GelMA, which made it easier to handle. In terms of water content and optical transmittance of the bioprinted scaffolds, we observed that scaffold with 12.5% GelMA concentration was closer to the native corneal stroma tissue. Subsequently, cell proliferation, gene and protein expression of human corneal stromal cells encapsulated in the bioprinted scaffolds were investigated. Cytocompatibility in 12.5% GelMA scaffolds... 

Nowadays, BDI architecture is of the most well known agent’s architectures. BDI architecture or the architecture in which the system is viewed as rational agents based on the attitudes of belief, desire and intention represents an abstraction of human deliberation based on a theory of rational action in the human cognition process. BDI logic introduced by Rao and Georgeff have been widely used as the theoretical basis of specification and implementation of rational agents. BDI logic is limited to deal with crisp assertion, while the assertions encountered in real world are not precise and thus cannot be treated simply by using yes or no. Moreover, In order to obtain more human like agents we... 

The use of super-swelling polymers is steadily increasing and the applications in industry are continuing to grow. With the authorization of the superabsorbents in food packaging by the Food and Drug Administration recently, demand may soon take off in the market. The worldwide production of SAPs is more than one million tons per year, representing a multibillion-dollar market. However, the increase in prices of petroleum products in recent years may be a drawback for these acrylic-based materials. Thus, there is now a need to develop natural-based super-swelling hydrogels which are more economical and environment friendly. In addition, the super-swelling gels are promising novel functions... 

Although rural inhabitants constitute a large portion of developing countries’ population, they have always been neglected in many ways. Expansion of equity, calls for a new concern in adequacy of rural development. The problem could be considered in two aspects: Firstly, there is a great tendency for immigration to nearby cities, hoping for a better life. This would result in more crowded cities, extended poverty and an increasing rate of crime mainly in suburban areas. On the other hand, the evacuation of farms and fertilized lands imposes great economical loss to the country. Therefore, development of rural facilities should be integrated into national policies to assure a homogeneous and... 

Airports are one of the most important elements of the aviation system that provide the ground infrastructure that is required for enabling or flight across the globe. Master Planning is currently the dominant approach to airport strategic planning. However, history shows that this approach can often result in costly mistakes. Because there are many stakeholders with conflicting objectives, deep uncertainty about the future, and many potential strategies, planners often narrow their scope by using a single forecast for the future, leaving out alternative strategies, and excluding stakeholders, resulting in a Master Plan that quickly becomes obsolete and may be opposed by some stakeholders.... 

As the size and complexity of software increase, the number of software vulnerabilities also increases. An examination of vulnerability reports shows that in addition to the fact that a large number of unknown vulnerabilities still exist in software, there is still no proper solution for identifying vulnerabilities that have been observed one sample of them exit in real-world software. The main reason for such an event is the lack of a suitable template for recognized vulnerabilities, which ultimately makes searching for them in other software a problem of scalability and high search cost. This thesis, recognizing the importance of the issue, presents a framework for extracting robust and... 

One of the most essential part of power system are transmission lines. Transmission of power from production centers to consumption centers is duty of these lines. Any disturbance in this duty make great losses to producers and consumers. One of the most disturbance in transmission lines are short circuits that occurred because of various causes. Most faults on transmission lines occurred in stormy weather that make more troubles for fault search. So we need a tool that can find location of fault precisely and quickly. This tool named fault locator. There are many algorithms for fault location and detection on power system transmission lines. These algorithms usually are dependent on very... 

According to privileged risks existing in process industries and intensity of their consequences, Safety investigation and risk assessment are highly significant in these unites. Execution of risk assessment in process unites has been constituted from two qualitative and quantitative parts. The most crucial issue in risk assessment procedure is uncertainties related to data and needed information, besides of various models presented. This subject frequently relates to deficiency, ambiguity, and inaccessibility of necessary information for specifying of risk assessment characteristics i.e., event reproducibility and their intensities. In this work for overcome these constraints, bow-tie fuzzy... 

In this thesis, we want to present methods that are able to solve the assignment tasks problem in a heterogeneous computing system. These methods are two hybrid methods that are constructed by composing Hopefield Neural Networks with Genetic Algorithms and the Simulated Annealing. First, we solve the relaxed problem by applying Genetic Algorithms and the Simulated Annealing and we compare the results of these ways with other traditional methods. Then, we solve the constrained problem with mentioned hybrid methods. The definition of the problem is as following: Consider a distributed computing system which is comprised of set of processors with different speeds but the same structure. We want...