Sharif Digital Repository

Every year, air pollution is causing immense harm to humans and the environment. To cause Air pollution, several factors are involved. Among these are the sources of emissions such as factories, power plants and Cars, meteorological factors such as temperature and wind speed and geographical conditions such as altitude, postal and looming around the area, land slope and soil type region. The aim of this study is to identify factors that affect the ozone concentration in Tehran, which could help identifying other secondary pollutants. For this purpose, a combination tailored to the geography of Tehran using CMAQ-WRF-SMOKE-made programs. This model includes four intervals each of which lasting... 

Solid-State Disks (SSDs) offer advantages such as no mechanical parts, low power consumption, and constant read latency. SSDs, however, suffer from shortcomings such as erase-before-update requirement and limited endurance.Redundant Array of Independent Disks (RAID) are commonly used in storage servers to enhance performance and reliability. To further enhance system performance, one can employ efficient Input/Output (I/O) scheduling algorithms suitedto the disk structure in RAID-based systems.In this thesis, we present an I/O scheduling method to improve endurance and performance of SSD-based RAID systems. In the proposed I/O scheduling algorithm, read requests are sent directly to SSDs and... 

Retail stores are one of the members of each supply chain which connect end customers to the other parts of supply chain. Matching customers demand with product supply, is one of the most important duties of retail stores. There are a big variety of products in retail stores and also many new products continuously enter to the stores, in the other hand available spaces for displaying products are limited and keeping those products in the shelves and warehouses will cost. However the amount and location of displaying products in shelves, directly effect on customer demands. When deciding about shelf space allocation, all of these issues should be considered. In addition, inventory control is... 

In the complex and dynamic world of today's communication networks, Software-Defined Networking (SDN) with its flexibility and programmability has opened new horizons in network management. These networks, by decoupling the control plane from the data plane, enable centralized and efficient management. Despite these advantages, optimizing routing in these networks remains a significant challenge, and increased latency in SDNs due to centralized processing in the controller and communications between switches and controllers is a critical issue that can severely impact the quality of service. Traditional routing methods face numerous challenges due to their static nature and lack of... 

Fog computing is essentially the expansion of cloud computing towards the network edge, reducing user access time to computing resources and services. Various advantages of fog computing, including reduced latency, improve user experience; however, user mobility may limit the benefits of fog computing. By moving users from one location to another, their distance from a fog service and consequently the latency may increase. One solution to maintain latency within an acceptable range is the migration of fog tasks and preserving the distance between the user and available resources. Although some research has been conducted on fog task migration, none of them have considered load balancing in... 

In this thesis the attitude dynamics, simulation and control of a flexible satellite with CMG (Control Moment Gyro) actuator in three-dimensional slew and rest-to-rest maneuvers have been studied. The flexible satellite is modeled as a rigid hub and two flexible appendages. The bending and torsion of the flexible panels have been considered. The equations of motion have been derived using the Lagrange method and assumed-modes approach is utilized for converting the partial differential equations of structural dynamics into an ordinary differential equation set. The MATLAB and SIMULINK software has been used for simulation and validation of the equations of motion. The simulation and control... 

The set of human arm, forearm, and wrist has the ability of performing very miscellaneous movements which has led to human inspiration for designing sorts of robots for various tasks. The aim of the present study is the design and simulation of a robot, similar to the human hand and arm. In the beginning, a shape-adaptive 2 DOF under-actuated mechanism which is actuated by one motor, is selected as the second and third phalanges of the human finger. Also the first phalanx of the finger moves independently by another motor. By adding a ratchet to the second joint of the finger, with the help of only two actuators, the feasibility of exerting isotropic force to the object in three phalanges... 

Schiff bases are used as prevalent ligands in coordination chemistry and are prepared easily. Their application as mild inhibitory agents for prevention of various steel’s corrosion in acidic solution has been proved. When their structure is altered, multi-purpose application for them is found. This property has led to a motive for research and study. In this study, electronic properties of a group of Schiff bases are investigated. The goal of this study is using quantum mechanics (QM) as a tool for specifying electronic properties of some of these bases. With respect to QM calculation which is done by density functional theory (DFT), their properties as inhibitory agents are studied. First,... 

Multi-camera vehicle tracking is a necessary part of any video-based intelligent transportation systems (ITS) for extracting different traffic parameters such as link travel times and Origin/Destination (O/D) counts efficiently. In many applications it is needed to place traffic cameras disjoint from each other to cover wide areas. In this work we present a system for tracking vehicles in such network of cameras. The proposed system includes new ideas for handling inter-object occlusion as the most challenging part of single camera tracking phase. This approach is based on coding silhouette of moving objects before and after occlusion and separating occluded vehicles by finding longest... 

Nowadays, adaptable, versatile and flexible nature of Flying ad-hoc Networks (FANETs) make them popular in many academic and practical fields such as real-time applications, civil applications, search and rescue operations, identification and logistics. FANETs are organized multi-UAV systems that can accomplish complex missions through cooperation and collaboration. The unique features of these networks, such as high mobility, low node density, high frequency of topology changes, and three-dimensional flight environment, create various challenges in communication, especially in packet routing. In this type of network, a subset of UAVs connects to the infrastructure, while the remaining UAVs...