Sharif Digital Repository

In the modern world of software engineering, software evaluation has earned a special position. The presence of consultation companies in evaluating the software will confirm this specialty. Web technology, as a new trend in computer science, has attracted the attention of many researchers and practitioners. As known nowadays, most of the software solutions are Web-based. Such software is technically called Web application. The methods of evaluating Web application include the use of traditional metrics in software engineering. The intelligence of the Web in computer science has been the core of much research.
This study is intended to use intelligence, as one of the new features of the... 

In this research, the effects of Rayleigh waves on the response of typical three-dimensional concrete faced rock-fill dams (CFRDs), considering dam-foundation interaction and spatial variability of earthquake ground motion are investigated. The time history of Loma Prieta earthquake (Gilroy 1 station) is used as input excitation. The dam is considered to be located in a prismatic canyon with trapezoidal cross-section. A substructuring method, in which the unbounded soil is modeled by the scaled boundary finite-element method (SBFEM), is used to obtain scattered motion and interaction forces along the canyon. Non-linear model is used for rock fill... 

Networked computers are expanding more and more around the world, and digital social networks becoming of great importance for many people's work and leisure. Emails, Weblogs and Instant Messengers are popular instances of social networks. In this thesis, the main target is to have an advertisement according to user favorites and interests by mining his/her interactions in digital social networks. Briefly, in our method social network users are categorized based on the topics exchanges between them in the network, these topics discovered by mining of flowing data in that environment, considering that these topics shows the user willing, finally relevant advertisements will be represented to... 

Well-Testing is a one of the usual methods in petroleum engineering for evaluating reservoir and well parameters. This method is based on measuring downhole pressure verses time in different production conditions and then drawing these data in different pressure-time graphs and evaluating reservoir characteristics and calculating reservoir parameters. This thesis describes the development of techniques for the automation of the model identification and parameter estimation of a well test interpretation, using Artificial Intelligence. The computer programs which are written in MATLAB software use Neutral Network toolbox to detect a model that is based on the pressure derivative curve, and... 

Loads from laterally spreading ground have been a major cause of damages to pile foundations in past earthquakes. Analysis of case histories have shown that damages are particularly intense when a nonliquefiable surface crust layer spreads laterally over underling liquefied layers. In this research the effect of lateral spreading due to liquefaction on single piles embede in a gently sloping ground has been investigated. Finite element method using OpenSees is used to model the pile and embedded soil. The soil profile for all models consisted of a nonliquefiable crust layer overlying loose sand with Dr = 30-35% overlying dense sand with Dr = 70-80%. The effect of geometric properties such as... 

An understanding of the effect of degree of cementation on static behavior of cemented soils in becoming increasingly important in design and analysis of geotechnical engineering problems. Naturally cemented coarse-grained soils are widely present in many parts of the world. Misunderstanding of the behavior of such soils could lead to under or overestimate of the soil parameters. Previous studies conducted by Prof. Haeri and his co-workers show that most of the alluvial deposit of Tehran, the capital city of Iran. The amount and characteristics of the cementation of the deposit varies in different parts from highly cemented in the north to non-cemented in the south. This deposit consists of... 

Oil reservoir simulation serves an important role in forecasting oil production. This forecast, in turn, helps to devise a production scheme for hydrocarbon reservoirs which is one of main objectives of reservoir management team. In this research, using the idea of logarithmic distribution of reservoir fluid pressure around a wellbore, a new method for simulation of naturally fractured reservoir is developed. This method is shown to be more fast and accurate than conventional methods in reservoir simulation. In this method Dual-Porosity formulation is used for description of fluid flow in fractured reservoirs. The governing equations then were discretized by Galerkin Finite element method in... 

In this project, investigation of C-N internal rotation in ethyl tetrahydro-1(2H)-pyridine carbdithioate and ethyl 1-pyrrolidine carbodithioate were investigated by dynamic nuclear magnetic resonance spectroscopy. The 1HNMR and 13CNMR spectra were taken at the variable tempratures around the coalescence temprature. Thermodynamic parameters were calculated by analysing the spectra and the outcomes were compared by the theoretical results. For ethyl tetrahydro-1(2H)-pyridine carbdithioate ∆G‡ was 14.3 (kcal/mol) and for ethyl 1-pyrrolidine carbodithioate ∆G‡ was 17.0 (kcal/mol) which were in accordance with the theoretical results. The analysis were done by the Spinworks program which... 

Heat transfer to combustion chamber walls is an unwanted phenomenon. Reduction of this heat transfer by using bidirectional swirl flow, as proved in past studies, can result in time and cost saving methods in design and fabrication of combustion chambers. Bidirectional Swirl flow, existing in vortex engine, maintains the chamber wall cool. This characteristic of such flow field, among with many other advantages for it, makes researchers more interested in studying the propulsion of it as well as its other applications. Bidirectional swirl flow in liquid fuel ramjet engines has the proven advantage of keeping the combustion chamber walls cool and in solid fuel ramjet engines in increasing the... 

Determining the best location for new wells is a complex problem that depends on reservoir and fluid properties, well and surface equipment specifications, and economic criteria. Various approaches have been proposed for this problem. Among those, direct optimization using the simulator as the evaluation function, although accurate, is in most cases infeasible due to the number of simulations required. This study proposes a hybrid optimization technique (HGA) based on the genetic algorithm (GA) with helper functions based on the polytope algorithm and the neural network. Hybridization of the GA with these helper methods introduces hill-climbing into the stochastic search and also makes use... 

Initial static shear stress caused by slopes or nearby structures' foundations can affect the behavior of the soil which is concerned many investigators during previous three decade. In this investigation, the effect of initial static shear stress on the liquefaction resistance of Babolsar sand has been probed using cyclic simple shear tests. Three different initial relative densities (Dr0=20%, 40% and 60%) and three different initial normal stresses (σv0= 50, 150 and 250 kPa) were considered in tests and four various initial static shear ratios (α) ranging between 0.0 and 0.3 were applied which leads to more than 190 distinct experiments. All tests were conducted under constant volume and... 

Although CO2 is an environmentally benign solvent, many organic solutes are only sparingly soluble in CO2. We use Monte Carlo simulations in the context of statistical perturbation theory, Widom’s particle insertion and expanded ensemble techniques in order to investigate the molecular properties involved in enhancing the solubility of materials in CO2. Our Monte Carlo simulation of diluted methane and its fluorinated forms showed that substitution of H atom with F atom, results in more favorable solvation, but with further increase of F atom (after CH2F2) due to small size of solute it is impossible for all CO2 molecules in the first solvation shell (FSS) to have a good orientation against... 

Thermodynamic modeling is a useful method for predicting of asphaltene precipitation due to various reasons, such as CO2 injection, mixing of different oils in oil storage and pressure changes. However, the application of solid model and thermodynamic micellization model, for prediction of asphaltene precipitation under gas injection condition, hasnot been improved. In this work, two computer codes which are based on two different asphaltene precipitation thermodynamic models, 1-Thermodynamic Micellization Model and 2- Solid Model, have been developed, and, used for predicting of asphaltene precipitation data reported in the literature as well as the experimental data obtained from high... 

It is widely accepted that under reservoir conditions there exists some degree of block-to-block interaction that may lead to capillary continuity. The formation of liquid bridges causing capillary continuity between blocks will significantly affect the ultimate oil recovery. However, accurate modeling of the growth and detachment of traveling liquid bridges which causes capillary continuity between blocks remains a controversial topic. In this work the generalized continuity and momentum equations along with fracture capillary pressure are combined to develop a mechanistic model for formation of traveling liquid bridges between blocks. Firoozabadi and Ishimoto (1994) model is considered for... 

Increasing the global demand for energy and decreasing the production rate of oil reservoirs have forced the oil companies to focus on enhanced oil recovery (EOR) extensively. This paper summarizes the design, reservoir simulation, and results of different gas injection scenarios in one of the Iranian complex oil reservoirs. This complex reservoir is located in the south west of Iran and is made up of sandstone, limestone, and dolomite layers. It is an under saturated reservoir with no gas cap but with a strong aquifer. Oil production has started in 1977, but due to strong aquifer the production is still in the plateau period. In this study, by simulation, it is estimated that natural... 

The most fundamental concept in considering electrical properties of reservoir rocks are formation Resistivity factor and Resistivity index which are defined by Archie and are useful in interpretation of well logging, evaluation of porosity and saturation. A theory on the relationship between formation resistivity factor and porosity, also resistivity index and saturation are presented by use of parameters Cementation factor and Saturation exponent. The Archie equation is valid only when the rock is strongly water-wet and clay free, which is not the case in carbonate rocks. Therefore the Archie equation cannot be generalized over the entire carbonate reservoirs. On the other hand influence... 

The advent and proliferation of computer networks have dramatically changed computing, communications and more importantly, our daily lives. The global network of computer networks, the Internet, has enabled novel ways of distributed information sharing that were unthinkable just a short decade ago. With invaluable opportunities comes the grand challenge of developing methodologies for collaborative capturing, processing, storage, dissemination and sharing of information. The present work takes an important step toward addressing this grand challenge. In particular, we study and evaluate a novel programming paradigm, referred to as “Distributed Semantic Programming”, in which semantical... 

Iranian Power industry has undergone fundamental changes since deregulation started in 2003. Currently, bulk trade of electricity in the industry is mainly conducted through a day ahead wholesale market, representing over 98 percent of the exchange of electricity within the grid. Although the current market regime is under operation for over 4 years, several political, cultural and operational obstacles have hindered effective evolution of the restructuring process. Low political support from privatization of the industry assets backed by lack of confidence and trust in market economies in general, and low economic incentive of the market players has slowed down formation of an effective... 

The optimum wave functions and calculation method were obtained using a 24 factorial design. Based on preliminary experiences, the following four factors at two level was selected: electron correlation, triple-ξ valence shell, diffuse function and polarization function.
The wave functions for calculating gas phase 1H chemical shifts of primary and secondary alcohols were optimized using factorial design as multivariate technique. Gas-phase experimental 1H chemical shifts of 18 alcohols were used to establish the best levels of theory for obtaining 1H chemical shift, among them the new experimental values of 1H chemical shifts of 10 alcohols were obtained in our laboratory. HF/6-31G(d,p)... 

VAPEX is a relatively new EOR process for the recovery of heavy oil. In this process solvent is used to form a vapor chamber within a reservoir. Vapor dissolves in the oil and diluted oil drains by gravity to a horizontal production well. The essential features of this recovery mechanism have been discussed in this study. Furthermore, a semi-analytical and a simulation study of VAPEX process have been performed on a specified Iranian heavy oil reservoir (such as Kuh-e-Mond). The aim of this study is to investigate an exponential functionality (correlation) witch incorporates all physical parameters that affect the production rate of VAPEX process in dimensionless form. The adjustable...