Sharif Digital Repository

Aspect-Oriented Software Development (AOSD) concentrates on separation of global cross-cutting concerns, or aspects. The weaknesses of Object-Oriented Software Development (OOSD) in localizing orthogonal concerns simultaneously leads to distributing them across several modules, and thereby creating modules that have to deal with various concerns. This usually results in poor modularization and difficulties in tracing certain requirements (especially nonfunctional requirements) to their implementations. The AOSD approach determines the common aspects that exist across modules created through OOSD, and modularizes them. Thus, AOSD takes the next step in creating modular software. Applying this... 

In this thesis, a power switch with a smart driver is designed. 4-ampere current can pass through the switch, and the driver is capable of switching the load with 50 kHz frequency. The smart driver consists of an internal oscillator, internal regulator, charge pump, current limit, a level shifter, overtemperature and over/under voltage circuit. All these circuits are designed and developed in high voltage BCD 0.18 um process and well discussed in the thesis. All four kinds of protections are designed and implemented; open load detection, short circuit detection, over temperature shut down, UV and OV detection. Charge pump idea is used instead of the bootstrap method, which makes it possible... 

This thesis proposes a probabilistic framework for evaluating and enhancing the community recovery process following an earthquake occurrence. This framework serves as a recovery decision support tool, aiming to enhance community resilience through the optimal allocation of limited available resources following a disaster occurrence. To this end, Bayesian network and agent-based simulation are integrated, each of which forming one of the modules of the proposed framework. The first module, namely, the Bayesian network, leads to situational awareness of the status of the community after the earthquake by fusing data from various sources. The data, such as the earthquake event characteristics... 

The purpose of this study is to investigate the distribution of air flow and temperature in electric machines. The fluid flow equations are solved by using the characteristic Galerkin. The unsteady equations of the air flow and heat transfer between the rotor, stator and radial cooling channels of the generator are solved by finite element method. Tetrahedral elements are used, but hexahedral elements can also be used. The upwind method is used to discretize the convection terms, but the central difference for the diffusion parts, that is equal to Petrov-Galerkin method in steady state situation. Due to the large number of channels and specific geometry, to reduce the computation costs, the... 

A high percentage of reinforced concrete buildings are not earthquake resistant because they are often designed based on old regulations, which do not satisfy the requirements of new earthquake codes. Construction weaknesses make buildings more vulnerable, and thus, different approaches are needed to strengthen structures to resist lateral forces. 3D Panel system brings together the best qualities of in-situ and precast systems and improves their shortcoming. It includes the advantages of precast systems, such as having relatively low labor costs, less waste material and machinery, reducing implementation time and improving quality control. At the same time, serious problems related to... 

Part 1: Techniques of production data analysis for single-phase oil and gas reservoirs have advanced significantly over the past few years. These techniques range from traditional (Arps and Fetkovich) to modern (they account for the variation of operating conditions at the wellbore). Although the production data analysis methods are used generally for single phase reservoirs, the application of these techniques for analysis of production data of a gas condensate reservoir may not yield the reliable answer due to the fact that the flow of fluid in gas condensate reservoirs is not single-phase. This study presents the treatment of the modern methods of production data analysis (single phase... 

In this study an internal combustion rotary (Wankel) engine and its specifications is analyzed and the proper lubrication system is described. The acceleration acting on apex seals, and engine speed fluctuations together with the leading and trailing cells gas pressure forces are analyzed in the present work using the second Newton law. The research shows that cell gas pressure effects are important and inclusion of these effects will provide results which are more compatible with the reality and lead to a much more accurate analysis of the system. Theoretical calculations reveal that gas cell pressure forces represent about 78% of the overall calculated force and ignoring these pressure... 

Hydrocarbon reservoirs may be classified on the basis of their drive mechanisms. In the reservoirs adjoined by water aquifers, waterdrive may be the primary production mechanism. The invasion of reservoir rock by aquifer water may have a significant impact on reservoir performance. Therefore, water influx into hydrocarbon reservoirs must be predicted accurately as a function of time, pressure history at the reservoir/aquifer interface, reservoir/aquifer size ratio, and aquifer characteristics.To forecast the performance in a waterdrive reservoir, an aquifer model simulating the fluid flow in the aquifer and flow from the aquifer into the reservoir is needed. Robust techniques for analysis of... 

As the published statistics of prestigious international institutes show, the share of natural gas from the energy basket of the world is rising. This increase is due to some reasons such as decrease in oil reserves, discovery of new gas fields, lower environmental problems, etc. The Islamic Republic of Iran is not an exception of this rule; but also because of huge gas reservoirs that Iran has, it becomes very important for the Iranian government. Hence, research for predicting the behavior of such reservoirs is a necessary need of oil and gas industry.Both thermodynamic and flow behavior of gas condensate fluids are more complicated than other reservoir fluids. Its complex thermodynamic... 

Control of line of sight (LOS) orientation is a fundamental prerequisite for virtually all dynamic applications in which an optical sensor is used to obtain images. In this research, a 3 DOF parallel mechanism is utilized to build a stable platform for high precision satellite photography. The platform may be designed based on the Stewart platform concept. The stability is obtained by controlling the roll, pitch and yaw of the mechanism. To apply linear control techniques and to use roll-pitch and yaw rates and also their absolute values, an active stable platform is designed. Line Of Sight (LOS) is a position vector from origin of a topocentric-horizontal system to the satellite of... 

The objective of this project is to study the behaviour and performance of an innotative floating offshore platform. Such Platform not only can be used for exploring oil from offshore fields, but for creating artificial islands, where land is in short supply. Due to its specific and, at the same time, simple geometry (symmetric), its fabrication does ont involve much complexity. Studies carried out on this platform include the investigation into its structural behaviour under gravitational (including self weight) and bouyancy forces. Studied cases include a number of platforms with different (geometrical) sizes and under 3 various bouyancy conditions (percentage), namely 1) 50% of the height... 

Fire is one the events which threatens the very existence of every building, residential, office, industrial or else. However, this threat is more serious with regard to buildings with steel structures. Steel, despite its many advantages over other structural materials, such as having high strength to weight ratio, ductility, toughness and resilience, has the disadvantage of rapidly losing its strength at elevated temperatures, i.e. in fire. Therefore, it is the responsibility of the designer to make the serious decision of whether to use steel, concrete, timber, or other materials for the structure of the building to be designed. Observations made during full-scale fire tests as well as...