Sharif Digital Repository

As the number of processing cores on a single chip continues to grow, the need for a high bandwidth, low power communication structure, will be the most important requirement of the next generation chip multiprocessors. Today, a major part of power consumption in multicore architectures belongs to interconnects. Due to these facts, reducing power consumption, as well as supporting high performance, is of major concern in these architectures. Optical interconnects have the potential to replace electrical wires to solve the bottleneck of communications in integrated circuits. Various routers and architectures with different points of view, have been recently designed considering existing... 

In this thesis, performance of doubly fed induction generators in wind turbine, under stator unbalanced voltage condition has been studied. Therefore, beside of presenting related equations and models for DFIG, drawbacks of DFIG performance under unbalanced voltage condition on variables such as electric torque, active and reactive stator power and stator current have been shown. Then, controller have been designed in the way that can eliminate electric torque oscillation, active power oscillation, negative sequences of stator current and rotor current. The controller is designed base on decoupling sequences in synchronous reference and stator voltage orientation method(SVO) that consist of... 

The human action recognition is one of the most important concepts of computer vision in recent decades. Most of the two dimensional methods in this field are facing serious challenges such as occlusion and missing the third dimension of data. Development of depth sensors has made easy access to tracking people and 3D positions of human body joints. This Thesis proposes a new method of action recognition that utilizes the position of joints obtained by Kinect sensor. The learning stage uses Fisher Linear Discriminant Analysis (LDA) to construct discriminant feature space. Two types of distances, i.e., Euclidean and Mahalanobis, are used for recognizing the states. Also, Hidden Markov Model... 

The non-stationary nature of brain activity signals and their many inter-subject differences have created many challenges in the practical applications of emotion recognition based on electroencephalogram (EEG) signals, such as brain-computer interfaces. In such a way, the use of traditional classifiers in classifying these signals leads to a significant decrease in accuracy when applying the classifier to a new subject. Domain Adaptation methods seem to be an effective way to solve this problem by minimizing the difference between the EEG signals of different subjects. But in the basic techniques for domain adaptation, looking at all subjects' data in the same look causes the loss of a part... 

The design and development process of menu systems has always been a focus of researchers and engineers in the fields of software engineering and human-computer interaction. Considering the large and complex nature of the design space, it is nec- essary to provide automatic methods that aid designers during the design process. In this study, natural language processing is used to investigate the semantic relationship between menu system commands. Users expect related commands to be conveniently located next to each other, and a properly designed interface satisfies this need. As a result of this research, a fast-text-based model is developed that uses the data of past menu systems. In a... 

Today, in different industries,as the use of high voltage DC power supplies is increasing, the need of output voltage precision also is increasing. One way to make High DC voltage is to use a multi-output DC-DC converter and makethe output series.Existing problems in measuring high voltages, results in this idea That in these converters, we measure and regulate only one of the outputs and estimate the others by circuit elements. In this estimatin, differences between the transformer parasitic elements are very effectiveon transformer various output voltages. In this thesis after a comprehensive study on the pulse transformer parasitic elements and choose a suitable model for it, the... 

Applications of high voltage power supplies is increasing. Microwave power module is one of the applications. In microwave power module, the dimensions of the power supply are very important. On the other hand, the parasitic elements of the transformer of a high voltage power supply are significant because of high insulation distances and transformer high turn ratio. These elements including stray capacitance and leakage inductance change the converter behavior. In this thesis, a method for dimensional efficient design of high voltage power supply used in microwave power module is presented considering and analyzing the transformer parasitic elements. Beforehand, at first, the transformer... 

In this project, a novel action recognition method, named Fisherposes, is proposed, which is improved by several space-time (spatio-temporal) methods afterwards. The proposed method utilizes skeleton data obtained from Kinect sensor. First, pre-processing is performed in which the scales of bodies are canceled and the skeletons become aligned in order to make the method robust to location, orientation, and scale of people. In Fisherposes method, every action is defined as a sequence of body poses. Using the training samples for the poses, a Fisher subspace is created which we name it Fisherposes. Moreover, a novel distance measuring function, named regularized Mahalanobis distance, is... 

Acceleration of healing process for crucial wounds has been remained a challenging issue and it is critical to improve treatments against infection during wound healing period. Among various antimicrobial agents, silver components has been extensively since they are resistant against a wide range of bacteria. In this study, we developed electrospun mats composed of Polycaprolactone (PCL) and Polyvinyl alcohol (PVA) loaded with major silver components using co-electrospinnig method. Chitosan- Ag nanoparticles was synthesized using chitosan via heating prior to electrospinning. Various amounts of Silver components including Ag+, Silversulfadiazine (SSD) and Chitosan- Ag NPs were added to PVA... 

With the increasing development of the semiconductor industry, the density integration of integrated circuits with affordable expenses has gained a special place between different researches. Nanolithography as a way to decrease the size of patterns has a significant contribution in integration of circuits. Scanning Probe Nanolithography (SPNL) is one of the most important nanolithography methods due to its ability to create patterns with an extremely high resolution and direct patterning. Scanning Near-field Optical Lithography (SNOL) has the advantages of the usage of optic such as non-direct effect on sample and the advantages of scanning systems such as high resolution. In first part of...