Sharif Digital Repository

Acidizing is one of the widely used practices of formation damage remediation. The success of this rather expensive job depends on the precise design and operation. Though, improper execution of an acid job, not only does not improve the formation damage but also can contribute to even more damage itself. For this purpose, it is critically important to thoroughly design an acidizing job conducting extensive lab experiments and utilizing numerical tools before operation in order for a successful acidizing. Unlike, carbonate acidizing, the chemistry of sandstone acidizing is very complex and challenging because of the wide variety of minerals and aqueous species present in the system. Hence, a... 

The standard cosmological model has been successful in describing many observations from widely different epochs of the Universe, from primordial nucleosynthesis to the accelerat- ing expansion of the present day. With the improvement of the number and the accuracy of observations, some inconsistencies among key cosmological parameters of the model have emerged. Many alternative models are proposed in order to alleviate these tensions. Pecu- liar velocities, the deviation from the regular Hubble flow of the galaxies, are an excellent probe of large-scale structure universe. In a ΛCDM universe, peculiar velocities can be mea- sured using linear perturbation theory, which in known as bulkflow.... 

The scarcity of potable water is one of the world's challenges. In the Middle East, this crisis is even worse and as a consequence, the most aggregation of desalination plants has been constructed in this area. However, brine effluent discharged from these plants entails serious environmental issues. Despite the extensive studies about the investigation of dilution and the area which faces the brine discharges as submerge jets, there are a few experimental investigations with a focus on the injecting brine discharge into the shallow environment. Whereas the Persian Gulf's coastal environment is shallow. Moreover, there is a huge construction of desalination held in this area. Accordingly,... 

In recent years, deep generative models have achieved incredible successes in various fields, including graph generation. Due to the advances made in graph generation by deep generative models, these methods have shown numerous applications from drug discovery and molecular graph generation to modeling social and citation network graphs. Graph generation is an approach to discovering and exploring new graph structures and has been attracting growing attention. One of the most challenging applications of deep graph generative models is molecular graph generation since it requires not only generating chemically valid molecular structures but also optimizing their chemical properties in the... 

PRP is a combination of two classic problems. First one is the lot-sizing and the second one is vehicle’s routing which have been studied for more than fifty years. The prp is solved in attempt to jointly optimize production, inventory, distribution, routing decision and as a result, it is a inventory-routing problem as a whole. Despite the fact that prp involves a complex instructor, both universities and industries have been so eager to this problem since last decade. In this thesis an integrated assessment of PRP and various technics for solving the problem have been discussed. Moreover, taking into account the structure, hypothesis, and the constraints of the problem, a... 

The purpose of this dissertation is proposing a probabilistic model in transition systems of records. In these systems, two acceptance state of finite and infinite string have proposed which acceptance state of finite string is called probabilistic finite automata of records and acceptance state of infinite string is called probabilistic buchi automata of records. The buchi automata of records is an operational semantic for Reo coordination language. Reo is a coordination language to coordinate existing component of a component based system. Reo circuits with non-deterministic and probabilistic channel can be modeled by proposing probabilistic buchi automata of records. In this dissertation... 

The lack of road safety imposes heavy costs on society. The cost of treatment, disability, travel time and mental disorders are examples of costs caused by unsafe roads in a country. One of the most effective manners to improve road safety over the last decade is to use safe driving incentives and in particular usage-based insurance. Usage-based insurance reduces road accidents by internalizing the cost of driving violations and the cost of vehicle usage.Risky behaviors and driving violations, especially speed limits violations, have a significant effect on increasing unsafe road traffics. Accordingly, in this Ph.D. dissertation, a new scheme of usage-based insurance was introduced to reduce... 

The constitutive modeling of material is clearly a keystone of successful quantitative solution possibilities. No finite element code will provide results of better quality than that of the constitutive equation implemented in it. In this study, a nonassociated three-invariant cap plasticity model is presented for material under compressive stress. Generalized single-cap plasticity is developed which is based on the hardening-softening material functions. The hardening functions are consisted of isotropic and kinematic parts. Using the definition of yield surface, material functions and nonlinear elastic behavior, as function of hardening-softening parameters, the constitutive elasto-plastic... 

Nowadays, Information Security is one of the most challenging issues in organizations. With the development of technology and the Internet, people insist on greater access to information and data. In addition to creating value-added for the organization, collecting a huge amount of data in the organization's database and using IT tools threat it by losing the funds and credibility obtained from customer confidence in different ways. Therefore, managing information security is necessary due to the current competitive environment. In spite of the advancement of technology, the existence of many complexities in this subject led to the growth of security incidents. Hence, the organizations’... 

Railway managers have strong economic incentive to minimize the cost of track maintenance in order to conserve safety standards and provide adequate service levels for train operators. The main object of this study is to provide a method for railway repairing and maintaining management and improve previous researchs.
In this study, a cumulative damage model based upon a nonhomogeneous Markov process is developed to model track deterioration. The maintenance of deteriorating facilities can be a great challenge because the process of deteriorating has random features for some facilities.
The genetic algorithm is used to find the optimal repair for each possible track state in the... 

Deteriorated old urban neighborhoods usually have no access to appropriate municipal services, and have small-sized buildings, densely populated areas, and earthquake-prone structures. Residents in these areas do not have the will and financial ability to renovate their aged properties. A questionnaire survey of the citizens living in the deteriorated areas of the City of Tehran showed that 80% of households do not have a positive monthly financial balance and cannot afford the cost of reconstructing their properties. Serious drawbacks of previous attempts to renovate deteriorated areas, including lack of adequate government funding, and adding to the dependence of local citizens on... 

Land-use and transportation are inter-related, such that land-use may be used to control transportation. This study aims to design a suitable combination of the residential and service land-use on one side, and the transportation system on the other side. The model presented in this study has two external and internal levels, and its objective is to minimize the cost of residence, receiving goods and services, and transportation. The performance of any combination of spatial allocation of population and employment, as well as transportation, is evaluated by the internal level of the model which determines the interaction between population, employment, and transportation. This is done by a... 

Expansions of large urban areas, as well as increase in the rate of car ownership, has given rise to the urban traffic congestion. One of the major approach to cope with the congestion issue is named Transit Oriented Development (TOD), which will cause changes in trip departure times, route choice, mode choice, and trip destinations. TOD also affects the land use in long-run periods. The goal of this study is to clarify the long-term impacts of TOD on land use and find the appropriate transit projects in order to abate the drawbacks of changes in land us. Land use/ transportation has been the subject of many recent studies. One of the previous studies investigates land use and transportation... 

Pavement maintenance and rehabilitation is an important problem in road pavement programming. Pavements experience significant distress over its life due to passage of vehicle (particularly heavy trucks), as well as abrupt variation in temperature (freeze and thaw). This would deteriorate pavements and reduces their serviceability. Rise of pavement maintenance costs places higher importance upon the need for maintenance programming. This study employs an evolutionary model to optimize the long-run benefit of the maintenance program. The model is stochastic in nature, and imbeds a Markovian decision procedure in the model to take into account such variabilities. The model is applied on... 

Dealing with complicated organizational situations in the current competitive and uncertain market requires making the best management decisions at the earliest time possible. As making the best decisions requires the possession of adequate and accurate knowledge, knowledge has become the most valuable asset of organizations. Knowledge Management (KM) spans managing the identification, capture, storage, sharing, usage and creation of knowledge. Using an appropriate Knowledge Management System (KMS) can ensure the provision of essential knowledge for decision making, and can manage the complexity of the competitive market by maintaining and managing the relevant organizational knowledge.... 

By means of classical Itô calculus, we decompose option prices as the sum of the classical Black–Scholes formula, with volatility parameter equal to the root-meansquare future average volatility, plus a term due to correlation and a term due to the volatility of the volatility. This decomposition allows us to develop first- and second-order Approximation formulas for option prices and implied volatilities in the Heston volatility framework, as well as to study their accuracy for short maturities.Numerical examples are given  

Software development process is a base ground for all software activities and ensures all aspects of the software. No quality is guaranteed without a definite process. Model-Driven Software Development process proposes an industrial method for software companies to produce the required software through model(s) and tools. On the other hand, Software Product Line imposes a set of frameworks and principles. As a result a tangible decrement of development time and cost along with an increment of quality is achieved. Mixing both processes creates a stronger industrial process in order to decrease the development time and cost. In this thesis, through a survey on both of the processes and related... 

It is so essential to study a safe dynamics of agricultural mechanical equipment during duty stroke, plus getting a rich information about the nature of the soil under processing and in many cases there are associated simultaneous problems, so the main aim of this study is to create a safe working conditions for such specific equipment to extend their life time span as possible as it could. This study will predict an un-usual working circumstances for agricultural tools including plough of course depending on some automated technologies with fast response supported by smooth working conditions. Simply, the proposed Investigative system consists of a linear potentiometric element with... 

Software Product Line is known as a process of developing family of the software together. The methods of building a software product line is trying to capture commonality and variety of this family of software and form a product line based on them. Commonality of this family of the software allows us reuse in every aspect of the development of software. Nowadays, software architecture as a one of the most important aspect of software engineering, plays major role in specifying the tasks and clearing the relationship between people. It can divide large and complex system to some sub-system and overcome complexity of the system. Software architecture forms a basis for communication among... 

A growing number of distributed information systems need to operate in open, dynamic and heterogeneous environments, and are required to adapt themselves to environmental changes in order to satisfy specific design objectives. These self-adaptive systems are inherently complex, mainly due to the complexity of their environments and the effects of dynamic adjustments made to their structure and behavior. Developing such complex systems is still an important challenge insoftware engineering.Agent technology is considered as an appropriate and powerful paradigm for developing complex and dynamic distributed systems. Intelligent/autonomous agents have been proved useful for enhancing flexibility...