Sharif Digital Repository

E-plane waveguide filters are good choices due to highly manfacturing accuracy in Q-band microwave devices.To increase the attenuation slop or selectivity of such filters one need to synthesis transmission zeros with cross coupled resonators.With this method for constanst degree and return loss, attenuation slop increases in comparison to direct coupled resonators.
In this thesis we designed and fabricated a Q-band 4th degree filter,with center frequency at 42.1746 GHz and bandwidth of 350 MHz with two transmission zeros. Results of simulations and measurments are given in chapters 3 and 5.
Microwave filters using coupled resonators are important components in microwave systems.... 

In the last two decades, Convolutional Neural Networks (CNN) have shown significant capabilities in artificial intelligence. These networks are able to provide comprehensive conclusions about the overall behavior a system by analyzing the relationship between the components of that system; Clearly, these networks have been successful in performing categorization tasks. However, there are no coherent theories as to why they work, and how to optimize them. On the other hand, according to recent research on the relationship between deep networks (in computer science) and Renormalization Group (in physics), convolutional networks seem to use a method similar to the Density Matrix Renormalization... 

The so called T(b) theorem for boundedness of generalized CalderonZygmund singular integrals is investigated. This theorem provides a criterion, in which boundedness of the operator is equivalent to a special condition for the image of some function under action of that operator.Then we discuss some applications of the theorem in analysis and partial differential equations  

global warming and air pollution due to the excessive consumption of fossil fuels have led to the proliferation of renewable energy sources (RESs). RESs are connected to the grid through power electronic converters and therefore, provide insignificant inertia and damping property for the system. As a result, the system overall inertia and damping is decreased and therefore, the system stability is jeopardized. This thesis presents a comprehensive small signal model for a virtual synchronous generator (VSG) integrated into a microgrid. In the developed state space, active and reactive power control loops of the VSG as well as resistances and reactances of the lines are considered. Based on... 

Financial benefits are no longer the only decision makers’ criteria and they consider environmental and social merits due to the modern nature of management and international competing. As a result, sustainable supply chain management (SSCM) rises noticeably in popularity among academics for researching on it and industrialists for applying it. Having reviewed respective researches, The SSCM is addressed by an integrated approach in this rsearch for selecting green suppliers and finding optimal production plan in two phase. In first phase, thank to related literature, a framework including environmental criteria is purposed for evaluating suppliers by Analytic network process method (ANP).... 

The purpose of this research is to develop a contactless angular sensor based on magnetic methods that in addition to having similar outputs to resistive angle sensors (contact potentiometers) has advantages such as longer lifetime and no sensitivity to contamination, moisture and dust. In this research, an angular GMR sensor is designed and manufactured and tries to present a product that meets the required standards and can be sold in domestic and foreign markets  

In this investigation, cellular structure of a weakly unstable detonation wave in H2/O2/Ar mixture is studied. The detonation is simulated using 2D reactive Euler equations and one step Arrhenius type reaction model developed by Mr. Barkhordari. The numerical technique is the high order Piecewise Parabolic Method on the basis of Godonov method. The numerical fluxes are computed based on a high-order extension of the Godunov's method; the piecewise parabolic method (PPM). The initial cell formation processes and different machanisms involved in cell size changes are studied. This study shows that the form of initial perturbation used to intrigate the instability of detonation is not important... 

Wind power is site dependent and is by nature partially dispatchable. Furthermore, good wind sites are far from grid. Due to these problems, and along with the existing limitations in the transmission networks, a comprehensive analysis over an extended time is needed to properly explore all potential wind sites for wind capacity allocation. This problem is computationally expensive and decomposition methods are required to break down this problem. Here Benders decomposition approach is used, which is a popular technique for solving large-scale problems, to decompose the original problem into a master and a subproblem. The master problem is a linear problem, which allocates wind capacity to... 

In the past few years, many research works on the controllable integration of metal nanoparticles and metal-organic frameworks were done, since the obtained composite material shows a synergism effect in catalysis and photocatalysis, drug delivery applications, gas, and energy storage, as well as sensing. For the first time, in this study, we employed template-assisted growth to synthesize Au-HKUST-1 Nanocomposite. XRD analysis entirely confirms that employing this strategy in synthesizing Au-HKUST-1 was wholly successful, and the plasmonic properties of this nanostructure were studied via UV-visible spectroscopy. In the course of synthesis, gold nanoparticles with 70nm diameter were... 

Single nucleotide polymorphs, There are changes caused by a mutation in a nucleotide in the Dena sequence. Mononucleotide polymorphisms are the most common type of genetic variation. Some of these changes have little or no effect on cells, while others cause significant changes in the expression of cell genes that can lead to disease or resistance to certain diseases. Because of the importance of these changes and their effect on cell function, the relationships between these changes are also important. Over the past decade, thousands of single disease-related mononucleotide polymorphisms have been identified in genome-related studies. Studies in this field have shown that the expression of... 

Industrial enzymes can generally be classified into three groups: carbohydrases, proteases and lipases, which account for a major part of the global enzyme trade. Proteases, in particular, have always been extensively studied and investigated due to their widespread use in various industries, such as food, pharmaceutical, chemical, and agricultural sectors. Proteases are a group of proteolytic enzymes that break down proteins and peptides into their constituent amino acids by hydrolyzing peptide bonds. Among the family of proteases, alkaline serine proteases have special biocatalytic abilities in both aqueous and organic environments. Their suitable resistance in alkaline environments and... 

Age-related macular degeneration (AMD) is the most common cause of vision loss in those aged over 50. There are two main types of AMD, Wet and Dry form. Wet AMD is more severe though more treatable. There are three conventional treatments for AMD including laser therapy, surgery and intravitreal injection of anti-VEGF into the eye. Delivery of drugs to the posterior segment of the eye is still challenging and several implants and devices are currently under investigation for their ability to stimulate the retina, producing visual percepts. The application of intravitreal bevacizumab (Avastin) has expanded tremendously from the time of its introduction into ophthalmic care since 3 years ago.... 

In analyzing the structural organization of many real-world networks, identifying important nodes has been a fundamental problem. The network centrality concept deals with the assessment of the relative importance of network nodes based on specific criteria. Central nodes can play significant roles on the spread of influence and idea in social networks, the user activity in mobile phone networks, the contagion process in biological networks, and the bottlenecks in communication networks. High computational cost and the requirement of full knowledge about the network topology are the most significant obstacles for applying the general concept of network centrality to large real-world social... 

As a robust and accurate classification of tumors is necessary for successful treatment of cancer, classification of DNA microarray data has been widely used in successful diagnosis of cancers and some other biological diseases. But the main challenge in classification of microarray data is the extreme asymmetry between the dimensionality of features (usually thousands or even tens of thousands of genes) and that of tissues (few hundreds of samples). Because of such curse of dimensionality, a class prediction model could be very successful in classifying one type of dataset but may fail to perform well in some other ones. Overfitting is another problem that prevents conventional learning... 

Studies show that a large proportion of sent emails are spam. Spam is one of the major problems of e-mail users that result in wasting time and cost. To overcome this problem different ways are used, one of the best ways is detecting spam based on their contents. Separating legitimate e-mails and spam within their contents can be categorized as text classification. So machine-learning approaches are extremely applied in text classification, that machine-learning algorithms can be used for spam classification. However, in the majority of these algorithms, training phase is in a batch. Whereas using incremental learning algorithms is preferred in many applications, especially spam detections.... 

In single service wireless cellular networks, two types of call are defined; new call and handoff call. New call blocking probability and handoff call dropping probability are two major parameters of QoS. Some call admission control schemes are proposed for handling new and handoff calls in the cell for keeping these QoS parameters under suitable values. In this work, we will introduce some call admission control schemes and will show performance analysis, advantages and disadvantages of them (under different channel holding times and same channel holding times for new calls and handoff calls). Then we will focus on two schemes and based on their ideas, we will propose a new call admission... 

Decision making often has different effects and results with unequal importance. Most of classifiers try to minimize the rate of misclassified instances. These classifiers assume equal costs for different misclassification types. However, this assumption is not true in many real world problems and different misclassification types have different costs. These differences can be applied by introducing the cost in the process of learning. In this manner, total cost of misclassification will be the evaluation metric of classification. In order to apply this metric to the problems, new learning algorithms are needed. Cost-sensitive learning is the related area of machine learning which deals with... 

Cellular learning automata (CLA) is a distributed computational model that is introduced recently. This model is combination of cellular automata (CA) and learning automata (LA) and is used in many applications such as image processing, channel assignment in cellular networks, VLSI placement, rumor diffusion and modeling of commerce networks, and obtained acceptable results in these applications. This model consists of computational units called cells and each cell has one or more learning automata. In each stage, each automaton chooses an action from its actions set and applies it to the environment. Each cell has some neighboring cells that constitute its local environment. The local rule...