Sharif Digital Repository

In this thesis, we study the properties of simplicial complexes Δ with the equality I(m) Δ = Im Δ for a given m _>2. The main results are combinatorial characterizations of such complexes in the two-dimensional case  

Nowadays, the world is based on the interaction between individuals, groups and different systems. The actual networks that have a complex structure and behavior are called complex networks. Complex networks are one of the new knowledge that studies the connections. The complex systems represented as graph, with non-trivial topological features—features that do not occur in simple networks.With the vast development of computer networks, complex networks appear in different categories such as social networks, citation networks, collaboration networks and communication networks. Data mining is the process of exploring hidden knowledge in data bases and it has applications in complex networks.... 

Complex waves possess complex propagation constants even in the absence of losses. Such waves may be excited in open- or closed-guided wave structures such as inhomogeneously or anisotropically filled waveguides, coupled right-handed/left-handed transmission lines, and periodic structures. In the absence of losses, complex modes appear in pairs with complex conjugate propagation constants. In open-guided wave configurations, complex modes will be of either the proper or improper (leaky wave) type. Proper complex modes are accompanied by an electromagnetic field that decays exponentially in the transverse direction, away from the waveguide. By contrast, electromagnetic fields associated with... 

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... 

Supply networks are often faced with disruptions that hampered the flow of goods, and have brought irreparable consequences. In this thesis, we evaluate the robustness of three echelon scale free supply chain networks consist of manufacturers, distributers and retailers from the perspective of complex network topologies and investigate the effect of assortativity and disassortativity level on the robustness of scale free supply networks. For this purpose, we use the degree preserving rewiring approach in order to increase and decrease assortativity and disassortativity of scale free networks. Then we use metrics in order to investigate the robustness and flexibility of supply networks and... 

This research aims to study fundamentals of design as a science for possible use in special structures. Special structures are referred to those structures that designers’ knowledge for which are insufficient. Designs of such structures are complex in the sense that we lack all necessary elements of design matrix; as well as proper steps to reach the unknowns. Introducing appropriate design strategy for such structures; we show how a design could be developed without specific needs for trial and errors. In this work, various design methodologies and especially “Axiomatic Design” have been examined. In addition, functional requirement and associated design parameters for structural design are... 

Information Technology In the recent years, Peer-to-Peer Networking and Applications has received significant attention from both the Internet users and research area. One of the most successful Applications of P2P networks is streaming the video which is applicable in Internet TV. On the other hand, Complex networks describe a wide range of networked systems in technology, nature and society, such as Internet, WWW networks, P2P networks, biological networks and social interactions.In this thesis we focus on mesh-pull based streaming networks and our goal is to propose a complex network model for such a P2PIPTV topology. To reach to this aim we consider the microscopic processes on each node... 

In this study, some properties of metallochlorophylls - compounds produced by replacing Mg2+ in tetrapyrrolic ring of chlorophyll b with divalent ions – of the forth period transit elements of the periodic table have been investigated. Using DFT/B3LYP method and DGDZVP basis set, structures of these compounds were optimized and the energy of electronic levels, Gibbs free energy of formation of complex, contribution of atomic orbitals to formation of molecular orbitals and partial charges in these molecules were computed. The results show that some properties of these complexes cannot be justified by the common theories of complexes. Among these properties is the negligible effect of... 

The subject of Secret Sharing refers to the methods that a secret information is shared (by a dealer) among a number of parties, so called participants, each having one or more shares, such that the predefined subsets of the participants, called authorized subsets, are able to regenerate the secret using their shares. A more general scheme which is called Multi Stage Secret Sharing (MSSS) is to share multiple secrets among the participants such that the authorized subsets can reconstruct the secrets in the consecutive stages; in these schemes, in addition to the individual shares, the dealer should provide the participants with a number of public values regarding the secrets. A Multi-Secret... 

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... 

The heteronuclear complexes [MePt(bhq)(μ-dppy)Au(PPh3)]PF6, 2, [MePt(bhq)(dppy)Tl]PF6, 3 and [Me2Pt2(bhq)2(dppy)2Tl]PF6, 4 in which bhq=benzo{h}quinoline and dppy=2-diphenylphosphinopyridine, were prepared by reaction of the mononuclear complex [MePt(bhq)(dppy)] 1 with 1 equivAuCl(PPh3), 1equiv TlPF6 and 1/2 equiv TlPF6 respectively. All the complexes were fully characterized using multinuclear NMR spectroscopy and ESI-MS spectrometry. In addition molecular structures of complexes 2 and 3 in solid state have been determined by X-ray crystallography that shown strong dative bonds between platinum and gold or thallium atoms. As shown by ESI-MS spectrometry, the Pt-Au bond in complex 2... 

A multi-agent system is a system consisting of several intelligent agents. In fact, a multi-agent system is a system that includes a large number of agents that communicate with each other through message transmission in a network structure. Multi-agent systems can solve problems that are difficult or impossible for a single agent or an integrated system to solve. Blockchain is an example of these multi-agent systems that has many use cases in different fields for example cryptocurrencies . A blockchain is a growing ledger consisting of records called blocks. In this thesis, we want to provide tools for the simulation of this multi-agent system so that we can model the issues surrounding... 

In this thesis, we review recent advances on controlling of complex systems. We provide in details, the concepts of synchronizability and synchronization controllability.Then we will investigate synchronization controllability under different pinning schemes, and propose a new pinning strategy to increase controllability and consequently decrease the number of required pinned nodes (known as driver nodes) to assure a stable synchronized state. We also study the network characteristics of resulted sequence of driver nodes. Finally, we will employ our proposed schemes to study the controllability of complex networks of chaotic Rossler oscillators  

The reaction of AuCl(SMe2) with two equiv of 2-vinylpyridine(2-Vpy) and one equiv of AgOTf gave the gold(I) complex [Au(2-Vpy)2], 1. Also the cationic gold(I) complex [Au(1,8-Naph)2][NTf2], 2, in which NTf2 is Bis(trifluoromethanesulfonyl)imide, has been prepared from the reaction of AuCl(SMe2), two equiv 1,8-naphthyridine and one equiv Ag(NTf2). The partial replacement of the NTf2 counter ion by PF6 using the reaction of 2 with one equiv TlPF6 leads to formation of the gold(I) complex [Au(1,8-Naphthyridine)2]〖"[NTf2]" 〗_("1" ⁄"3" ) 〖"[PF6]" 〗_("2" ⁄"3" ), 3. The solid state structure of 3 was determined using X-ray crystallography and its optical properties have been studied at room... 

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 this study, a number of chloro and nitro cobaloxime complexes with triphenylarsine and triphenylstibine synthesized from dichloro precursor and their structure were studied. These complexes were identified by FT-IR and 1H-NMR methods also their solid state structure studied by X-ray crystallography of single crystals. Intramolecular interactions of these complexes analyzed and studied by NCIPLOT 3.0 and VMD 1.9.3 programs which has different kind of intramolecular interactions which can be identified by their colors. All these complexes have strong hydrogen bond between hydrogen of oxime group and oxygen of other dimethylglyoxime ligand. Also coordinate covalent bond among ligands and... 

A social network represents a set of entities and their relationships. Telecommunication networks, online social networks, and paper citation networks are some examples of networks in real world. Nowadays, analysis of social networks is an interesting research area with important applications. Particularly, managers of the social networks and the decision makers often require intelligent decision support for futures study in these social systems. The demanded decision support systems make it possible to define the desired social problem and to analyze the ”what-if scenarios.“ Computer simulation is an appropriate approach toward such decision support systems. In this approach, the desired... 

Let (M; g) be a Riemannian manifold. Using classical Stokes’ theorem one can show that the equality (dω; η)L2 = (ω; δη)L2 holds for smooth forms ! and η with compact supports, where δ is the formal adjoint of d . There are some examples of Riemannian manifolds for which the above equality does not hold for general forms ! and η i:e: smooth square-integrable forms such taht d! and δη are also squareintegrable. In the case that the above equality holds for such general forms on a Riemannian manifold (M; g) , we say that the L2 - Stokes theorem holds for (M; g) . In 1952, Gaffney showed that the L2 - Stokes theorem holds for complete Riemannian manifolds. But at that time, there was no powerful... 

A new dioxomolybdenum(VI) complex, (Cis-[MoO2(L)])n, has been synthesized by reacting 4-bromo-2-((2-hydroxy-5-methylphenylimino)methyl)phenol as a ligand and [MoO2(acac)2] in methanolic solution. For characterization and structure determination of the synthesized complex, different techniques were performed such as elemental analyses, 1H NMR, IR, UV-Vis and X-ray crystallography. The complex was tested as a catalyst for the homogeneous epoxidation of olefins, using tert-butyl hydperoxide (TBHP) as an oxidant. The catalytic system showed high yield, selectivity and turnover number in olefin epoxidation reactions under atmospheric conditions. For example, when the molar ratio of catalyst,... 

Due to study of reactivity and interaction of Schiff base complexes, as models of biological system such as vitamin B (B6 and B12) and enzyme (cytochtome c oxidase), some mono and binuclear Zn(II), Pd(II) and Co(II) Schiff base complexes were synthesized and characterized. As a model for vitamin B6, tridentate Schiff base ligands derived from the condensation of water soluble aldehyde with the amino acids (glycine, L-alanine, L-valine, L-leucine and L-phenylalanine) in the presence of Zn (OAc)2.2H2O give rise to the formation of five new water soluble Zn(II) complexes. The IR spectra of these complexes show that, there are prominent stretching vibration of the azomethine band (HC=N) at...