Sharif Digital Repository

The role of data in the advancement of science and engineering has been emphasized due to the abundance and verity of data, the improvement in online computing speed, the enhancement of quality of life in the era of cyber-physical systems, human aspirations for new discoveries, and the need for real-time decision-making in autonomy. Furthermore, the emergence of new computing capabilities has created additional demands for data. Utilizing data-based methods has become a necessity, as the system model is not always available or cannot be represented as a comprehensive mathematics. System modeling can be extremely challenging and complex, which can hinder controller performance or even render... 

Smoke is the largest cause of fire related deaths. A smoke control system is an engineered system that modifies smoke movement for the protection of building occupants, firefighters and properties. Unfortunately, in case of fire, stairwells and elevators are frequently filled with smoke, preventing effective evacuation. Many smoke control systems use mechanical fans to control smoke by providing positive pressure at strategic locations. Pressure difference across a barrier can control smoke movement by preventing smoke on the low-pressure side of the barrier from migrating to the high-pressure side. Building designers use codes and rules of thumb to design their building against fire.... 

In recent years, teleoperation systems have been widely used in bio-medical applications such as minimally invasive telesurgery, telerehabilitation and telesonography, and also for outer space exploration and radioactive material management. In bilateral teleoperation systems, the human operator applies force on the master robot to control the position of the slave robot in order to perform a task in a remote environment. A nonlinear robust adaptive bilateral impedance control strategy is proposed in this research to provide the absolute stability of multi-DOF teleoperation systems with communication delays. Using this controller, instead of conventional position tracking (synchronization)... 

In this project design of adaptive neural network controller for uncertain nonlinear systems in the presence of different restrictions has been investigated. After providing introduction and motivation, two general forms of nonlinear systems including strict- feedback and pure- feedback have been introduced. In order to solve the problem caused by each restriction, a solution has been proposed. For the strict- feedback nonlinear systems several restrictions are considered such as, unknown dynamic model, unmeasured state, input saturation, unknown control directions, time delays in states and input. Stability analysis based on the Lyapunov theorem has been established. In addition, two kinds... 

Nowadays, due to the indensible role of electrical energy in life of societies, the reliability of service should be provided in an economic form. Researches has shown that, about 80% of faults occur in the distribution network. In a distribution network that is equipped with automation systems, through the acceleration in the determination of the fault location, and also possibility of reacting against transient and steady faults, the electricity interruption time duration is minimized. This thesis aims to determine the number and to locate the auto reclosers and fault indicators in a distribution network optimally. To make it economically feasible, a limited number of these devices and... 

Growing rate of eutrophication in receiving waters has made the enhancement of wastewater treatment plants to advanced methods of nutrients removal as necessary. Nitrogen and Phosphorus as the nutrients can reduce the quality of water and even make it unusable. Phosphorus is known to be one of the main reasons of eutrophication and creation of algal bloom. In this study, chemical-biological method for phosphate removal from the municipal wastewater is studied. Experiments are implemented for hydraulic retention times of 4, 8 and 16 hours, total intake concentration of phosphorus 7 ppm, COD 400 ppm and Nitrogen 25 ppm. Ferric Chloride as the precipitator chemical substance injected into the... 

Eutrophication and algae growth is one of the consequences of high concentration of nutrients in surface water bodies; therefore, both phosphorus and nitrogen existing in wastewater or at least one of them should be decreased to a standard amount before entering water to rivers. This can prevent eutrophication and detriment to the ecosystem of rivers. An investigation on both biological and chemical phosphorus and carbon removal in low loading rate influent ( below 100) has been carried out in this research. Investigated topics includes aerobic COD removal in IFAS reactor, comparison of biological nutrient removal to the combination of chemical and biological method, effect of the order of... 

Recent advances suggest that many of the issues involving in improving water quality could be solved by using nano particles. Aquifer and groundwater remediation are also critical issues. Becoming more important as water supplies steadily decrease and demand continues to increase. Although some of the remediation technologies available today are , they are costly and time-consuming, especially pump and treat methods. A wide range of nano particles have been used for the removal of organic and inorganic contaminants. In the first part of this work, zero-valent Iron nano particles was synthesized and was covered with nickel as catalyst. Diameter of the synthesized nano particles was... 

Our ultimate goal in this thesis is to design a chaotic receiver for detecting small targets in sea clutter. Sea clutter at low grazing angle has a spiky behavior and in this thesis we desire to model this irregular behavior in the chaos theory frame work. Using a trend similar to statistical detection theory, we will obtain the suboptimal chaotic receiver and investigate the receiver noise effect on the optimality or sub optimality of the detector. Chaotic detector can be used in the coherent and non coherent mode. Although the coherent detector has a superior performance, the efficiency of the non coherent detector is acceptable as well. We will investigate the efficiency of the chaotic... 

We discuss and classify all four dimensional black hole solutions to Einstein-Maxwell-Lambda theory. These solutions contain a black hole region with an event horizon. The cosmological constant can be nonzero and the black hole may possess electric and magnetic charge. We classify solutions according to their asymptotic behavior. Three major parts are asymptotic-flat, asymptotic-de Sitter and asymptotic-Anti-de Sitter and in all of them we discuss Schwarzschild, Reissner-Nordstrom, Kerr and Kerr-Newman black holes separately. Black holes can also have NUT charge and acceleration parameter which make the solution singular in one direction. As a result, these solutions are asymptotically... 

The determinants of business cycles and how to deal with them are amongst the most important issues in macroeconomics. Using the annual data between 1980 to 2012, available for six oil producing members of Gulf cooperation council, we draw a connection between trade structure and business cycle synchronization. In fact, we try to answer whether the same trade structure in these countries with very similar characteristics has led to synchronized booms and recessions among them. Assuming cross correlation, different estimation methods, including common correlated effects, confirm the positive significant effect of trades tructure on business... 

The DNA Molecule carries genetic information in almost all living organisms. The information coded on DNA is an instruction which organizes and conducts all living activities of the living organism. The role of DNA in biological processes is so fundamental that life, as we know, is not possible without DNA. Therefore, studying the biological properties of DNA is crucial for understanding the nature of life. In biological conditions, DNA molecule can be found in highly packed configurations. Since the DNA is a rather stiff molecule, the formation of these configurations cost a considerable amount of energy. The elasticity of DNA plays an important role here. The important question is: how... 

The fuel consumption of displacement ships is one of the vital and sensitive issues in the marine transportation industry, which affects all economic and environmental aspects. There are few important parameters for displacement ships that can be changed and optimized to reduce fuel consumption and the resulting pollutants. In this study, extreme trim has been selected as one of these important parameters and it has been studied numerically using Star CCM+ software. It should be noted that the extreme trim approach is used when returning from a trip (when there is no load). The results obtained in the extreme trim mode showed a decrease of 26.76% in the resistance of the KVLCC2 tanker-ship... 

Classified ads are one of the first E-Commerce formed after the introduction of the internet to the world which is still popular. Divar is one of the main online classified ads and thousands of transactions are happening daily. The transaction of demandant and supplier happens in a risky relation that needs trust to facilitate this transaction. In this research, we are trying to study trust models in the context of C2C E-commerce. As there are no structural assurance and feedback mechanisms in Divar, we decide to study the initial trust of members due to a lack of information from each other. In this research, we gather data from 385 participants by an online questionnaire. The results show... 

In recent years, chromatographic techniques as one of the most important analytical techniques have been greatly developed from instrumentation and data volume point of views. On the other side, multivariate curve resolution (MCR) techniques as a branch of chemometrics have potential for the analysis of multivariate and huge data sets. In addition, MCR methods have been developed very fast in these years and their potential have been shown in the analysis of different types of chemical data. Thus, combination of sophisticated chromatographic techniques (e.g. gas chromatography-mass spectrometry (GC-MS) or comprehensive two-dimensional gas chromatography (GC×GC)) with MCR techniques can be... 

All rotating machines (such as internal combustion engines, reciprocating compressors, propulsion systems, etc.) experience torsional vibration during Start up, continuous working conditions and blackout. Torsional vibrationis due to pressure rhythms, engine dynamic torques, etc. All components of a rotating system must convey dynamic torque in addition to the static torque.Excessive Torsional vibrations cause wear and damage such as gears, gear teeth damage and failure to the main shaft.Online monitoring of torsional vibrations of the machine can be displayed machine condition at any moment and consider the risk in early diagnosis. Shaft torsional vibration monitoring can detect cracks in... 

Nowadays, water pollution and water sources decreasion, is one of the important issues of our world. Treatment of polluted water and wastewater and recycling of those to industries and common uses, is very necessary. Dyes, is one of the biggest parts of water pollutants, especially, in textile plants. There are some ways for dye removal, in the industries; including biological, chemical and physical methods. Among of these methods, physical removal of dyes through adsorption (with Activated Carbon or other adsorbents), is very popular. Hydrogels are three-dimensional hydrophilic polymer networks, introducing very good swelling rate, mechanical properties and pollutants adsorption. In this... 

Breast Cancer is considered one of the most common cancers among Iranian women. Every year, seven thousands women start suffering from this disease. Since 70 percent of this patients live over 5 years, after this disease starts, there are 70 thousands women who are suffering from the cancer. The average age of getting the disease in Iran is 5 years lower than that of the global level. Studies show that compound containing Chromene and Carboxamides are appropriate candidates for preventing breast cancer. One of the most important fields of researches in Chemistry and Bio-Chemistry is QSAR which is used to relate the structure of molecules to their activities. In this study, molecular... 

In this project, the feasibility of hydrocarbon waste water treatment with low concentration by physical- chemical treatment methods will be discussed. The purpose of this thesis is to investigate the feasibility of reusing the water outlet of the oil and gas refineries, in the region of ASALUYEH where there is an urgent need for water. By using activated carbon and wooden absorbent (absorption method) efficiency of this method was determined. Both coagulation and flocculation methods were investigated. To design and optimize various operating conditions on the adsorption process the RSM method was used. Temperature, residence time, feed concentration, amount of adsorbent, and adsorbent ... 

Energy of graphs first defined by Ivan Gutman in 1978[1]. Let G be a graph with (0,1)-adjacency matrix A and let λ_1≥⋯≥λ_n be eigenvalues of A. Grap h energy is defined as the sum of absolute values of the eigenvalues of A and is shown by ɛ(G). let H_1,…,H_k be the vertex-disjoint induced subgraphs of graph G, it is proved that energy of G is at least equal to the sum of energy of H_i subgraphs, where the summation is over i. Also by partitioning edges of G to L_1,…,L_k subgraphs, energy of G is at most equal to sum of energy of L_i subgraphs , where the summation is over i. In this thesi s we study energy of graphs, specially...