Sharif Digital Repository

The concept of defining set in matching theory, recently has been taken into consideration by chemists and mathematicians because of several important applied problems in chemistry and mathematics. This concept is studied extensively in vari-ous areas of combinatorics and graph theory. The idea is to obtain total combinatorial structure of one object uniquely, based on some special information about it. Defin-ing set has been studied in various areas of graph theory like colouring, matching , orientations of graphs and etc. and many researches have been done in these areas. What we focus on, in this thesis is the defining set in matching theory that has been called “forcing set”. A minimum... 

Stochastic Algebraic Topology studies stochastic or less known spaces that depend on many random variables from the perspective of algebra. Examples of such spaces included random graphs of Erdos and Renyi and random simplicial spaces of higher dimension . In this thesis , we study algebraic aspects of these spaces such as homotopy groups and homology groups from probabilistic point of view , when the number of vertices of these spaces tend to infinity . The study of these spaces have a lot of applications, since the data for a given space can be incomplete . They are also used in big system structures. We have given a collection of new results in stochastic algebraic topology of two... 

Complex directed networks are widely used in representing, modeling and summarizing various homo and heterogeneous real networks such as protein-protein interactions, social and twitting networks, brain connectomes, chipsets mapping and marketing. While working on undirected networks in the hope for detecting communities or any other static and dynamic structures, has been on agenda of many physician and computer scientists, dealing with directed ones seems more challengeable for quick advances. Availability of theoretical basis especially symmetric adjacency matrix recommends modeling with undirected graphs but we believe that directed graphs are more general and practical to model real... 

Global Positioning System (GPS) is one of the most widely-used systems nowadays. GPS receivers are frequently integrated along with other communication systems in hand-held devices like cellular phones, tablets and etc. Therefore, implementing receivers with low power consumption (for longer battery lives) and high sensitivity (in order to detect the weak GPS signal) has attracted the attention of many researchers. With the purpose of designing such a low-power and sensitive receiver, we have studied the recently proposed low-power schemes. We have proposed a new architecture for the QLMV Cell; the circuit in which main blocks associated with RF front-end are stacked on top of each other in... 

This thesis is focused on development, modeling and simulation of a complete 6DOF elastic flapping air vehicle (FAV). In this respect the aerodynamic modeling is performed using a recent experimentally validated generalized modified strip theory (GMST) that considers the unsteady effect of wake and leading edge vortices via the Theodorsen function and Polhamus analogy respectively. The FAV wing structure is modeled using an elastic plate whose dynamic behavior is determined via a modal approach that is also verified with experimentation. The resulting novel integrated aerodynamic and structure (IAS) equations of motion are simulated for case study of FAV flight. Subsequently, since the IAS... 

In most radio receivers like superheterodyne receivers, a weak desired incoming signal is accompanied with many interferer signals that are much more powerful than the desired signal itself. These interferers, also called blockers, can cause a great disturbance in the functionality of the receiver. Due to gain compression and an increase in the noise figure (NF) of the receiver, the blockers should be filtered before the arrival at the output of the LNA. Because of the low quality factors of the available on chip inductors and in order to eliminate the out of band interferer signals and image frequency (in superheterodyne receivers), usually an external surface acoustic wave (SAW) filter is... 

Deployment of demands, increase in users and new services highlight the necessity of effective frequency allocation i.e. dynamic allocation instead of fixed allocation. Cognitive radio is a proper solution for dynamic frequency allocation. Cognitive radio can scan the spectrum and use the idle bands for transmitting and receiving data. The main part of this radio which is responsible for the most pivotal task is spectrum sensing. Recently, varied methods have been proposed to sense the spectrum. The scope of this research is on designing a very high-speed spectrum sensing system. In this thesis, in order to meet the required scan rate, a tunable complex filter with 40MHz pass-band has... 

In the first project, we have described the preparation of quadruply linked naphthalimide compounds 3-6. These compounds showed weak and strong excimeric emissions in solid and solution states, respectively. The experimental and theoretical results showed that the adjacent naphthalimide rings were oriented in solution so that intramolecular interchromophoric interactions enhanced the quantum yield efficiencies. However, although the strong intramolecular π and solute-solvent interactions in solution were replaced by n→π*, inter- and intramolecular π-interactions in the solid state, the naphthalimide units were aligned so that the quantum yield efficiencies were diminished. Also, a rise in... 

Paclitaxel is used as a drug against breast and ovarian cancers. Although paclitaxel has high biologic activity, it has very pour solubility in water like some other drugs. Since drugs should be solved in water to be absorbed by the body, for absorb enhancement, we should use carriers which includes both polar and non polar sites. eta-Cyclodextrin which has this feature is capable for producing inclusion complex in its hydrophobic pores with non polar materials. In this project by adding polymeric polyacrylamide branches on beta-Cyclodextrin, polymeric nano structure has been developed to enhance water solubility in comparison with pure beta-Cyclodextrin. Study on producing polymeric nano... 

Ambient intelligence is a new paradigm in human computer interaction in which smart actor interact with the surrounding environment and be helped in to reach their goals. One of the main principles in smart environments is the interaction between user and the system. Better interaction leads to a better user satisfaction. In explicit interaction, context plays an important role in interaction quality. One of the main parameter in interaction is the environment complexity. Environment complexity itself consists of other factor such as size of the room, number of devices, density of devices, size of the devices and etc. In this study, we have investigate the effect of two factor, environment... 

As sequencing technologies have advanced in the field of single cells, it has become possible to investigate complex and rare cell populations and discover regulatory relationships between genes. The detection of rare cells has been greatly facilitated by this technology. However, due to the large volume of data and the complex and uncertain distribution of data, as well as the high rate of technical zeros, the analysis of single cell data clusters remains a computational and statistical challenge. Dimensionality reduction is a significant component of big data analysis. Machine learning methods provide the possibility of better analysis by reducing the non-linear dimensions of data. A graph... 

As mobile multimedia services become popular, it is expected that mobile devices provide more multimedia functions such as real-time video playback, TV watching, and video games. However, real-time video applications running on mobile devices are heavily constrained by their limited computing power, compared to high-end consumer devices. In order to playback a high resolution video on mobile devices, a typical approach would be to fully decode video bitstream into the pixel-domain, and then spatially downscale the decoded frames at a desired resolution. However, due to large computation and memory required for decoding followed by downscaling, this approach is unsuitable for real-time video... 

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... 

Application of convolution-based transforms such as Fourier transform and wavelet transform are among the widely-used approaches in structural identification problems. These methods, however, are mostly based on a classical damping model for the structures. Hence, such methods cannot be used to accurately identify the modal properties of non-classically damped systems, such as structures equipped with energy dissipated devices, base isolated and multi-segment structures. In this study, complex-valued wavelet transform is used to identify the dynamic properties of structures with arbitrary damping models. This method is known to be able to identify the modal properties of highly damped... 

Complex network studies grow by the scientific community, thanks to the increasing availability of real-world network data. The importance of using analysis on this type of network algorithms and community structure is one of the most important problems in the field of complex networks. Community Detection in a multidimensional network is still under investigation in the research community. The aim of this research is to give an algorithm for community discovery. We have reviewed the basis for multidimensional network analysis and will present a solid repertoire of basic concepts and analytical measures, which take into account the general structure of multidimensional networks. Then, we... 

Considering the world's diminishing oil reserves, as well as the growing demand for oil and energy consumption, Enhanced Oil Recovery (EOR) techniques are becoming increasingly important in the attempt to improve oil production. Engineering salinity waterflooding has gained widespread attention and popularity in the last two decades due to its environmental friendliness, lack of expensive additives, low operating costs, and ease of use as an oil extraction process. The goal of this study is to use an innovative method to develop a mechanistic approach model that simulates and forecasts the mechanism and performance of the engineered water flooding process. Wettability alteration, the most... 

In this study, two units of production of synthesis gas has been stimulated into 2 forms of natural gas complex (steam/Co2¬) reforming and dry reforming. They have been examined from technical and economical views. The product from this process is synthesis gas by the unit ratio of Hydrogen and Carbon Monoxide which is used in Arak petrochemical complex for producing 2EH. For producing this synthesis gas in 900C (reactor temperature) and 15 bar of total pressure , the ratio of feeding parts into reforming reactor for total input carbon (methane and other hydrocarbon) and Carbon dioxide gas and water vapor in representation ( [CH4 + other hydrocarbons : CO2 : H2O ] ) for complex reforming ... 

The aim of this study is to mimic water oxidizing complex to find new materials and also to understand their rules in this matter. To achieve this, manganese complexes containing 2,4,6-tris (2-pyridyl)-1,3,5-Triazine, 1,10-phenanthroline, 1,10-bipyridine, Schiff base, amino acids, 2,6-pyridinedicarboxylic acid, 2-pyridinecarboxylic acid have been synthesized and characterized by elemental analysis, IR, EPR, ESI-MS, electronic absorption spectroscopy, electrochemistry, X-ray diffraction and oxygen evolution in presence of oxone and Ce(IV). It is shown that the reaction between Mn(II) complexes containing 2,4,6-tris¬(2-pyridyl)-1,3,5-Triazine, 1,10-phenanthroline, 1,10-bipyridine,... 

Precise leak detection by acoustic signal analysis calls for robust similarity measures to estimate the time delay between recorded leakage signals and minimize the probability of false alarms, in the face of dispersive propagation, multiple reflections, and unknown correlated, uncorrelated and impulsive background noise. Providing evidence that higher order modes and multi-reflected signals behave like sets of correlated noise, this thesis uses a regression model to optimize residual complexity in the presence of both correlated and uncorrelated noise. This optimized residual complexity (ORC) is highly robust since it takes into account both the level and complexity of noise and signal,... 

Petroleum contains a large variety of metal compounds with vanadium and nickel being the major metals. Some 6–34% of the total vanadium content is made up out of metallo-oxo-porphyrins, also referred to as petroporphyrins. Metalloporphyrins have long excited interest as oxidation and epoxidation catalysts. In the other hand the selective oxidation of sulfides to sulfoxides is of interest because of the importance of sulfoxides as synthetic intermediates in organic synthesis. A range of sulfides can be selectively oxidized to the corresponding sulfoxides in good yields using catalytic quantities of vanadyl complexes. Vanadium oxo tetraphenylporphyrin VO(TPP) catalyst is successfully applied...