Sharif Digital Repository

Continuous-variable quantum key distribution (CV-QKD) protocols, that share an unconditionally secure key between at least two legitimate parties, are based on the modulation of information on the continuous characteristics of light. CV-QKD is low-cost, has a high rate, and is compatible with conventional technology. However, one of the major drawbacks of CV-QKD is its poor performance at long distances. Such a limitation can be overcome with the assistance of noiseless linear amplifiers (NLAs). In this thesis, we aim to use Quantum scissor (QS), as a realistic NLA, to overcome this limitation. To this end, we suggested a three-photon QS that truncates all multiphoton number states with... 

Bread holds a significant place in the daily lives of Iranians, making the bread supply chain as one of the country's most vital product supply chain. The Iranian government has undertaken the responsibility of supplying the bread chain, and to achieve this, a specialized mother company was established. As a result, this company manages all aspects of this supply chain. Initially, the company's database and macro-policy objectives were examined to provide recommendations that align with its goals. One of the proposed suggestions was to optimize the extra-provincial transportation, which plays a crucial role in the supply chain. This proposal was chosen and thoroughly investigated. By... 

Embedded systems usually have severe limitations on power consumption. One of the reasons is that many embedded systems are battery operated. On the other hand, the battery is a non-linear source of energy, where the lifetime depends on how the system drains power from the battery, or in other words, the battery lifetime is dependent on battery discharge current curve. The nonlinear behavior of batteries is due to their inherent characteristics, where the rate capacity and the recovery effects are believed as the two most well-known and important factors. Also, embedded systems are usually fanless with limited cooling equipment, therefore temperature management is a prominent issue in these... 

Titanium dioxide (TiO2) is important because of wide applications such as self cleaning surfaces and using in photoelectrochemical cells .Recent researches have shown that addition of silicon dioxide into TiO2 increases hydrophilicity of SiO2-TiO2 and improves surface properties. Until now a little research has been done on the double layer TiO2/SiO2 system; therefore, this system is suitable for studying. In general this thesis consists of theoretical and experimental parts .In the experimental part, multilayer systems of SiO2/TiO2/Glass have been selected (thickness of SiO2 is 20 nm) and surface morphology and hydrophilicity have been investigated by Atomic Force Microscopy (AFM) and... 

In this study a new metallic damper, namely Corrugated steel plate Honeycomb Damper (CHD) is presented. The CHD proposed ease of manufacturing and implementation in various structures with a stable energy dissipation characteristic when subjected to lateral loading. The basic configuration of the CHD consists of two steel plates that are bent to form trapezoidal corrugations. The plates are then welded together along the bent lines to build the honeycomb geometry. In order to investigate the behavior of the CHD, first a closed-form expression for the elastic stiffness and yield strength was obtained by the matrix analysis method. Then, to study the non-linear behavior of the CHD, three... 

The importance of transversely isotropic and functionally graded materials and also plates in industry necessitates studies on these kinds of structures. This study works on the buckling of simply supported rectangular transversely isotropic FGM plates subjected to in-plane uniaxial or biaxial static loads. For this purpose, discretization method is applied and the aforesaid inhomogeneous plate is divided into arbitrary number of sublayers parametrically (N). With the help of displacement potential functions, coupled different equations for each sublayer are simplified to two uncoupled different equations in terms of the potential functions. These governing equations for transversely... 

During the over balanced drilling operation in high permeability or fractured formations, drilling fluid loss and in more severe occasions fluid lost occurs which causes many problems and dangers and delayed the drilling operation until it was repaired. On the one hand, because of the high value of this material, and on the other hand, due to the increase in rig/day costs resulting from lost circulation control, leads to a significant increase in drilling costs. In this research, polymer-fiber composites have been designed and manufactured using extrusion method and have been investigated as fluid lost control agent in the laboratory scale for the first time in Iran. The effective parameters... 

One of the important questions in mathematics is generalized. In case of metric spaces, one of the questions is: Can we extend notions of Riemannian geometry to arbitrary metric spaces smoothly? Ricci curvature is one of the most important concepts in differential geometry. Ricci curvature is defined for the Riemannian manifold and has many applications in mathematics and physics like Einstein’s equation in relativity theory. There is a good notion for a metric space having “sectional curvature bounded below by K” or “sectional curvature bounded above by K”, due to Alexandrov. Can we define the concept of Ricci curvature in metric space? A motivation for this question comes from Gromov’s... 

Seismic design codes reduce loads by using response modification factor. Because of the reserved strength in structural elements and capacity of structure to dissipate energy, structures can be designed for lower seismic loads. This factor has modified over time. In this thesis, the effect of the reduction in behavior factor on the response of two kinds of reinforced concrete systems were evaluated. Moment resisting frames and dual systems with different heights and regularity in plan, heve been design according to the behavior factor which is recommended in the 3rd edition of the Iranian codes of practice for seismic resistance design of buildings (Standard No. 2800). Drift and... 

Generally, nowadays, machine learning methods are used in many different areas for their superiority over other methods of prediction. Although being a tough task, stock market prediction with machine learning approaches is being spread due to satisfying results published ever yday. Machine learning methods usually use varied kinds of data ,including structured data such as market data, technical indicators and some fundamental data as well as unstructured one entailing text and graph data in order to enhance their predictability capacity. In this thesis we aimed to find out more about the importance and the contribution of structured data in prediction and we tried to attain a framework... 

Internet is the largest multi-purpose, self-reliant, complex and distributed computer network across the globe. The nodes of this network are placed in every place like homes, offices, military camps, schools and all other locations by utilizing many different communication protocols, media and capacities. Furthermore, by rapid technology development, there are many newly born applications utilizing internet in new ways such as Internet of Things systems. The explosive growth of technology causing accelerated addition of new nodes to the internet, and any new single node may have several new unpatched vulnerabilities. This is a serious issue for managing this vast chaotic configuration and... 

This thesis presents an inventory control system which is based on Meta-heuristic Algorithms.In this thesis we will optimize the input values of our tree-echelon inventory model (keeping costs,stock worth,reorder costs,...) with these Algorithms. The presented method is able to determine the optimal stock level, costs of system and number of shipments in the system. The method is basically a decision support system (DES) and it is able to provide the order scheduling parameters of goods at operational level. The aim of the current research is to demonstrate that a Meta-heuristic algorithmis capable of solving complex inventory problems and with future improvements it is able to achieve...