Sharif Digital Repository

Advances in IC fabrication makes possible have systems on chips. In this thesis we have designed and fabricated a digitally controlled bias chip for a transceiver which can be programmed by its digital interface. In this thesis, briefly we review basics of voltage regulators and methods for controlling them. Then we introduce high voltage 0.18um CMOS technology. In this thesis, we describe the requirements of a specific transceiver and present a system to overcome these requirements. This system has positive, negative and internal regulators, a five-bit analog to digital converter, temperature sensors, power amplifier controller and digital serial interface. In this thesis, we present a... 

Autonomic nervous system (ANS) controls involuntary activities of the body, e.g. heartbeat function and blood circulation. Common tests used for evaluation of the functionality of ANS system in regulation of the cardiovascular system include heart rate variability (HRV) analysis and studying the changes in heart rate or blood pressure during deep respiration, sit-to-stand or head-up tilt table test and Valsalva maneuver. Test parameters affect the amplitude of the variations of the cardiovascular signals. Therefore, in the recent years, analysis and modeling of the interaction between the relevant signals, e.g. heart rate, blood pressure and respiration, have been widely used for the... 

High voltage dc-dc converters are widely used in industrial applications. One of the methods for generating the high voltage is series connection of isolated voltage sources which can be produced by a multiple output converter. One major problem of multiple output converters is their cross regulation. In this project, the operation of a full-bridge based dc-dc converter (FBBC) is investigated in both single output and multiple output cases and analytical expressions for its output voltage and cross regulation are derived. Then, the effect of different parameters of the converter on the cross regulation is studied. It has been shown that increasing the input voltage of the converter improves... 

The gaps in the existing studies on L2 listening comprehension have been highlighted in the literature of second language learning. Accordingly, the necessity of the qualitative investigations in this field has been frequently addressed by the scholars (e.g., Vandergrift, 2007). The primary purpose of this study was to investigate the use of dynamic assessment (DA) in L2 listening comprehension within a group of six advanced EFL learners to extract the patterns of teacher mediation and learner reciprocity moves through a dyadic examination of their interactions. The examination of listening self-regulation was another incentive behind this study. This research also investigated learners’... 

In this project, an inverting Buck-Boost converter with two negative linear regulator is designed, implemented and measured in CMOS 0.18μm-HV BCD technology. Input voltage of Buck-Boost converter can vary from +15V to +28 and output voltage is digitally adjustable from -1V to -10V. Maximum output current of the converter is 300mA. A current mode controller and a lag compensator is used to control the converter. A high speed highside current sensor is designed and used in current mode controller. Sampled current of the current sensor is also used in a current limit circuitary to limit the maximum current of highside switch. Two negative linear regulators are placed at the output of the... 

High voltage pulse generators are widely used in the radar systems, laser, medical, food processing and etc. One of the pulse quality criteria that was analysed in this thesis is the pulse to pulse regulation. Pulse to pulse regulation is important in various fields. In the radar applications pulse to pulse instability caused undesired errors in the signal processing and limitations in the tracking of the targets. In Free Electron Lasers (FELs) non identical pulses cause RF phase shift in the each pulsed power supply and creates instabilities in the electron beam. Pulse quality is essential in medical application so that in the treatment of cancer an improved precision in delivering the... 

Seismic isolation is a method for seismic-resistant design of structures against earthquake and is one of the important control of structures technologies. Codification and publishing of codes for design of seismic isolation takes place widely since 1980s and this codification has undergone extensive evolutions during its developing process. In this project initially the developing process and fundamentals of codifying regulations of seismic design have been investigated and then the developing process of codifying regulations of seismic isolation in current important international codes like ASCE7-05, Eurocode 8, and Japanese code has also been considered. After considering these two... 

Undoubtedly, energy is one of the most important components of progress in any country. Despite some existing imagery about the future of human access to new and non-renewable energy sources, it is now safe to say that energy is a limited resource that is becoming increasingly difficult to access over time. Utilizing the experiences of developed countries in the field of optimal management and advancing strategic goals in the field of energy is one of the necessities of the country today. In this dissertation, using the meta-combined method, the experiences of the United States of America, China, Saudi Arabia, Norway, Singapore and India as countries that each have one of the advantages in... 

Energy harvesting from wasted environmental energy to power low-power electronic devices has emerged as an enabling technology for wireless applications in the past decade. The purpose of this technology is to provide remote power sources and/or recharge storage devices such as batteries and capacitors. This concept has environmental implications in reducing chemical waste produced by replacing batteries and potential monetary benefits that also reduce maintenance costs.Energy harvesting (EH) from untapped natural energy sources is common nowadays due to the increasing demand for electricity. Sources have the potential to generate micro to milliwatt power, depending on environmental... 

Flow Mediated Dilation (FMD) is a non-invasive method for endothelial function assessment providing an index extracted from ultrasonic B-mode images. Although utilized in the research community, the difficulty of its application and high cost of ultrasonic device prevent it from being widely used in clinical settings. In this study we show that substituting the ultrasonic device with more easily handled and low cost photoplethysmography and electrocardiography is possible. We introduce new indices based on the photoplethysmogram (PPG) and electrocardiogram (ECG) and show that they are correlated with the ultrasound-based FMD index. To this end, conventional ultrasound FMD test was carried... 

In spite of the fact that failures in distribution systems constitute a high percentage of customer’s interruptions, they have received less attention than generation and transmission systems at least in the amount of academic and industrial publications in the past decades. However as the business turns its attention to customers from consumers, focuses are moving toward power distribution systems in recent years. Its main problem that makes this high percentage of contribution in customer’s interruption is their widespread applications through all the places that there is a civilization. Contribution of many components in the system leads to high failure rate and because they spread every... 

The regulation is necessary for the electric distribution networks as a natural monopoly. Regulators have been applied the Performance Based Regulation (PBR) for the control of price. The common model of PBR is price cap. Price cap creates sufficient incentive for cost efficiency. However, it decreases the service quality in distribution systems. The aim of this thesis is to design a comprehensive model for improvement of service reliability in the presence of PBR. An incentive model is developed using reward-penalty theory and yardstick theory. Reward-penalty theory is a financial approach that rewards the utility with good reliability and penalizes the utility with poor reliability. The... 

In this research, it has been tried to design two controllers for a KVLCC2 tanker assuming unknown hydrodynamic characteristics and its mathematical model in order to maintain its course and speed. At first, due to the lack of an experimental model of a vessel, a three-degree-of-freedom MMG model of the KVLCC2 vessel was modeled in the SIMULINK, MATLAB, to be used as a basis for other tests and simulations. Therefore, by using the designed three degree of freedom model, all parameters affecting the floating maneuver were examined. In the next section, using the DNV standard, we designed two wind and sea current systems for system input disturbances. And finally, by using dynamic models of... 

The oil refining industry, as the first oil supply chain, is of great importance. By examining the issue of the Iranian Oil Refining Industry, using the game theory, one can find an accurate analysis of the barriers to the development of this industry. For this purpose, the main factors affecting the oil refining industry, the government and the refinery's owner, are modeled and their benefits are considered. By examining the relationship between these actors and their actions, the following strategies are proposed to improve the administration and regulate the Iranian oil refining industry:
1- Refining feed prices, according to the quality of crude oil (sulfur content and API... 

Gene regulatory modeling in different species is one of the main aims of Bioinformatics. Regarding the limitations of the data available and the perspectives which should be taken into account for modeling such networks, proposed methods up to now have not yet been successful in yielding a comprehensive model. In one of the recent researches, the Gene regulation process is considered as a nonlinear dynamic stochastic process and described by state space equations. Afterwards, in order for the unknown parameters to be estimated, Extended Kalman Filtering is used. In this thesis, first of all, Gene complexes are taken into consideration instead of genes and afterwards, Extended Kalman... 

Gene regulatory network consists of a set of genes; interacting with each other via their protein products. Such interations lead to the regulation of the genes’ production rate. A breakdown in the regulatory process, may lead to some kinds of diseases. Therefore, understanding the gene regulatory process, is beneficial for both diagnosis and treatment. In this thesis, gene regulatory networks are modeled by the means of dynamic Bayesian networks. We have used sampling based methods, in order to learn the network structure. As these methos have a very high computational cost; we have used a correlation test to prune the search space. This way, an undirected network skeleton is obtained; for... 

This thesis studied the definition of a green building and the elements associated with the construction of a green residential apartment in comparison with traditional buildings with respect to condition of Karaj city. The first step in green construction is preparing a guideline. For this, LEED (Leadership in Energy and Environmental Design) the most well-known code for green buildings is used and Adapted with Iran’s National Building Regulations. Creating a checklist to rate buildings is one of the most important parts of Green Building Regulations. To achieve the points, US LEED certification is analyzed in both qualitative and quantitative perspectives. A questioner is applied in... 

In this study, our objective is to simulate the growth of frost for humid air passing through pressure regulators. The study is carried out in two main stages. First, we use an empirical method to model the formation of frost for a humid-air passing over a flat plate. The model is a semi-2D one and that it is limited to predict the frost growth at a particular station along the plate, considering the local flow heat transfer parameters. We show the validity of results comparing with available experimental data. Second, we numerically simulate the frost formation and growth for a humid air passing between two parallel plates. In this regard, the semi empirical method is suitably coupled with... 

Nowadays, According to the improvement of technology, especially in power electronics, electric shipboards are preferred over traditional ones. Better maneuverability, lower emission, higher efficiency and reliability are the most conspicuous merits of this type of ships. Notwithstanding the fact that electric shipboards have many advantages, some serious problems may arise in these ships. Since the thruster motors of these ships are usually induction motors and they are fed by the microgrid of the ship, and taking into ACcount that thruster motors consume a huge amount of the generated power by the synchronous generators, the concept of infinite bus is inexistent in these microgrids. Hence,... 

In recent years, advances have been made in the field of miniaturization of the devices (in order to increase their efficiency, lessen the materials needed for the constructions and experiments, reduce costs and energy usage) resulting in the dramatic increase of surface to volume ratio in these devices. This progress has led to the dominance of surface forces which can be used to control very important interface phenomena having a special application such as electrokinetic. Using today’s manufacturing technology; it is possible to construct micro-nanochannels made from different materials such as silicon, glass, quartz, polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA) whose...