Sharif Digital Repository

For several years, self-organizing networks have been introduced by 3GPP to reduce the costs of mobile operators. Self-organizing networks, by introducing a kind of intelligence to the mobile network, will cause optimal performance and, as a result, reduce the operating costs of operators. Improving network coverage and increasing user data rates are always among the priorities of operators to increase profits and customer satisfaction. Coverage and capacity optimization is one of the most important functions introduced in self-organized networks. In this study, in addition to the coverage and capacity optimization function, the load balance optimization and the contradictory interaction of... 

One of the most crucial methods to Ensure correct software performance is testing. On this ground, one of the most critical discussions regarding software testing is the effectiveness of a test suite. Program state coverage is a criterion for determining the effectiveness of a test suite. This criterion indicates the number of program states that are executed for the lines. Since the total number of program states cannot be calculated to measure coverage, this criterion proposes a fixed number of 10 to measure program state coverage. Also, according to calculations for the program state in the execution of each line, the time complexity of this criterion is high. In this thesis, providing... 

Wireless sensor networks (WSNs) have recently achieved a great deal of attention due to its numerous attractive applications in many different fields. Sensors and WSNs possesses a number of special characteristics that make them very promising in many applications, but also put on them lots of constraints that make issues in sensor network particularly difficult. These issues may include topology control, routing, coverage, security, and data management. In this thesis, we focus our attention on the coverage problem. Firstly, we study the best current solutions in the literature. We choose one of them as the basis of our work and study it thoroughly as the core model of our coverage model.... 

Locating wireless transmitters is one of the most important issues. That’s why many researchers have worked in this subject recently. Communication Engineers always want to optimize the productivity of wireless transmitters. They prefer to cover a region completely by minimum cost, so they use analytical tools for solving this kind of problems. This type of optimization is very useful for cellular Networks. There is a different kind of wireless services such as high-speed Internet services; their goal is maximizing the covered demand points by minimum cost not covering all of them. Experts use maximal covering location problem for modeling this kind of problems. At first, an extension of one... 

In this thesis, an inventory- location model considering capacity constraints and coverage radius is described in which the capacity is determined based on the maximum accumulation inventory. This model, through minimizing the sum of the fixed facility location costs, transportation costs and safety stock and working inventory costs, concurrently, determines warehouse location, assignment of retailers to warehouses, shipment sizes from the plant to warehouses, working inventory and safety stock levels at the warehouses. This problem can be formulated as a nonlinear mixed integer program in which the objective function is neither concave nor convex. Lagrangian relaxation is incorporated for... 

Nowadays because of imbalance in supply and demand in the house industry, industrialization of building construction is one of the best ways to solve this problem. Currently, there is a strong tendency to develop guidelines for the design of Cold-Formed Steel (CFS) with different sheathing boards as seismic resistant shear walls. Also, the behavior of this systems is not very well known yet and more research is needed. In this work three K-braced frames with and without sheathing boards under lateral cyclic loading investigated experimentally. The first specimen as a control specimen is without sheathing board, second specimen was sheathed with Fibre-Cement board in one side and gypsum board... 

Titanium alloy and aluminum alloy 6061-T6 were successfully joined by resistance spot welding. The microstructure and mechanical properties of the lap joint were investigated. The microstructure of joints was inspected by OM, XRD, and SEM. The results reveal that the reaction between liquid aluminum and solid titanium were caused welding-brazing joints, which restricts the formation of IMCs. The microstructure in the aluminum side is a type of transition structure, which is considered to be the same microstructure that connects the columnar dendrite and Equiaxed dendrite in similar aluminum alloy RSW. The welding current has the most significant influence upon the tensile shear and cross... 

In this research, we consider the question of finding approximate bounds on some of computational geometry problems with uncertain data. We use color spanning set to model the uncertainty. Given a set of n points colored with m colors in d-dimension. The problem of minimum diameter in color spanning set model is finding a set of m points with distinct colors so as to minimize diameter of the points. We give an algorithm with an approximation factor (1 + ϵ) with running time O(21ϵd .ϵ−2d.n3) which improves the previous results. Next,we consider a new problem of finding bounds on unit covering in color-spanning set model:Minimum color spanning-set ball covering problem is to select m points of... 

It is the main idea of present thesis to provide a micromechanical method as a general treatment for several fundamental problems of the piezoelectric inhomogeneities. For initial demonstration of pertinent methodology, a single piezoelectric inhomogeneity of ellipsoidal geometry, under non-uniform far-field loading is considered. Accordingly, it is taken equivalent to elastic and dielectric inclusion problems connected by proper eigenstrain-electric field. This approach is named the electro-mechanical equivalent inclusion method (EMEIM) and requires that the electroelastic fields of the inhomogeneity to be equal to fields of the equivalent inclusions. Afterwards, the complex problem of... 

A DNA sequence is the information source of living kinds. Information of this sequence is at its constructing bases which has four different kinds. Sequencing DNA is necessary to resolve this information. At 1977, Sanger reported the first sequence of a DNA string. Recently, a human DNA string can be sequenced with 1000 in ~2 hours. Knowing DNA sequence helps to find function of each organism, predict and cure diseases (especially in cancer). Next Generation Sequencing (NGS) methods are based on shot-gun sequencing which fragmentize DNA strings and sequence each fragment. After sequencing, processing information of DNA is performed by the processing machine in two different types: alignment... 

Increasing in size and complexity of digital designs has made manufacturing process more complex and enforces more complexity in verification of designs. This makes it essential to address critical verification issues at the early stages of design cycle. Such a complicated designs needs to be tested for fabrication faults as well as functional faults. Several attempts have been made to raise the quality of testing methods with automatic test pattern generation (ATPG) and design for testability (DFT) methods in logic and lower levels. Although these techniques try to increase the testability of a circuit considerably, but there are always some overheads in area, power and performance.... 

The main subject of this project is to present a new algorithm for multiple RF sources localization by means of a group of robots. This problem (locating multiple radio sources) could be utilized in many domains, either military (passive radars) or civil (search and rescue) uses. Confronting detrimental effects of real environment on wave’s propagation pattern is the main challenge in this problem. Optimized movement of robots has been chosen as basic strategy to overcome this challenge. Presenting a general solution for this problem requires researches in four topics. The first one is simulation of environment and sensor with main objective of evaluating obtained algorithms’ performance.... 

The problem of guarding orthogonal art galleries with sliding cameras is a special case of the well-known art gallery problem when the goal is to minimize the number of guards. Each guard is considered as a point, which can guard all points that are in its visibility area. In the sliding camera model, each guard is specified by an orthogonal line segment which is completely inside the polygon. The visibility area of each sliding camera is defined by its line segment.Inspired by advancements in wireless technologies and the need to offer wireless ser- vices to clients, a new variant of the problems for covering the regions has been studied. In this problem, a guard is modeled as an... 

Given a set of obstacles as an arrangement of geometric shapes in the plane, we would like to find a path from the initial point s to the target point t that crosses the minimum number of obstacles. In other words, the goal is to determine the minimum number of obstacles that need to be removed to exist a collision-free path between s and t.On one hand, this problem can be used for measuring the strength of barrier coverage which is a fundamental concept in wireless sensor networks (WSNs), and on the other hand, it has been considered as a robot motion-planning problem. The objective of barrier coverage is to guarantee that any path from the start point to the target point, will intersect at... 

The use of formal methods in the software development process has many advantages. One of the benefits is extracting test cases from formal specification with test coverage criteia. In this study, we tried to extracting control flow graph form Z language. Using this graph and control flow graph coverage criteria, test cases are derived from Z. A tool to automate the generation of test cases from Z also produced. This tool uses the CZT, describing formal language Z receives and uses the standard graph covers, set of test cases stems. Using mutants, the proposed method was evaluated by this method was able to achieve a score of 92%  

The large number of unit tests produced in the test-driven development (TDD) method and the iterative execution of these tests extend the regression test execution time in TDD. This study aims to reduce test execution time in TDD. We propose a TDD-based approach that creates traceable code elements and connects them to relevant test cases to support regression test selection during the TDD process. Our proposed hybrid technique combines text and syntax program differences to select related test cases using the nature of TDD. We use a change detection algorithm to detect program changes. Our experience is reported with a tool called RichTest, which implements this technique. To evaluate our... 

This research focuses on finding an appropriate method for increasing wear and corrosion resistance of hard coating TiN PVD and chromium. The substrate was made up of 42CrMo4 (DIN) steel (used for marine industries) and coated by TiN Arc PVD process and hard chromium electro-deposition. The results of these two coatings are compared and the better coating which is TiN Arc PVD is suggested. To find the best method for coating, several test studies are organized such as: the mechanical and tribological properties of TiN PVD and hard chromium coatings for wear and corrosion resistance applications are organized. The potentiodynamic polarization technique was used to measure the corrosion rate... 

Wireless communication networks are undergoing a significant transformation from coverage-driven deployment of macrocells to user-centric and cluster-based capacity-driven deployments of low-power base stations (BSs), usually at the locations of high user density. On the other hand, the increasing irregularity and randomness in the locations of nodes has led to an increased interest in the use of random spatial models along with tools from stochastic geometry and point process theory for their accurate modeling and tractable analysis. To this end, this thesis investigates clustered networks for different wireless applications. In this regards, comprehensive and tractable analytic frameworks... 

In the unit clustering problem, given a set of points on the plane, the goal is to group these points into minimum number of clusters of unit size. In the online version, the points arrive one by one and upon each point’s arrival, it must be assigned to some cluster. Another related problem is online unit covering in which moving clusters after opening them is not allowed. In this project, the online clustering and online unit covering problems are studied in two dimensional Euclidean space. An online algorithm with competitive ratio of 5 is presented for the online unit covering problem. In addition, lowerbounds of 2:5 and 4:66 are established for these problems  

Nowadays by increasing the number of processing cores in system-on-chip, using networks-on-chip, as an optimized interconnection foundation for transferring data between processing cores is inevitable .Based on this, the necessity of designing and implementing an optimized structure for testing network-on-chip, considering various overheads such as power consumption, latency, bandwidth and area, becomes an important issue in designing network-on-chip. The purpose of this project is to design an optimized structure for testing routers and connecting links in network, which considers power consumption overhead, latency and area overhead on one hand, and fault coverage on the other hand....