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Face Detection in Color Images
, M.Sc. Thesis Sharif University of Technology ; Kasaei, Shohreh (Supervisor)
Abstract
Human face detection is an important research area with several applications such as human computer interface (HCI), face recognition, surveillance systems, security systems, and content-based image retrieval (CBIR). Face detection problem can be stated as “determining whether there are human faces in the image” and if there are “returning the location of each human face in the image” regardless of its position, size, scale, orientation, and lighting condition. In this thesis, we have proposed a new face detection method which combines the AdaBoost algorithm with skin color information and support vector machine (SVM). First, a cascade classifier based on AdaBoost is used to detect faces in...
Investigation Increasing Corrosion Resistance of Reinforcement in Concrete
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
corrosion of steel reinforcements in concrete is one of the most important reasons for durability reduction of offshore structures. To reduce the diffusion rate of ion reactivity in concrete and its reinforcement surface, different methods such as chemical change and coating of reinforcement and concrete are used. In this research for increase corrosion resistance, effect of Pozzolanic additive materials such as fly ash and micro silica , in optimized percentages, 25% and 10% by weight of cement respectively, the percentage of polypropylene fibers improved 2.5% volume of concrete and Ferrogard-901 industrial inhibitor with 3% by weight of cement in concrete mixing plan, were investigated....
Real Time Car Model and Color Recognition Using SVM
, M.Sc. Thesis Sharif University of Technology ; Jamzad, Mansour (Supervisor)
Abstract
Recently many works has been focused on Automatic Security Systems. Car type and color recognition systems are needed in vehicle based access control systems in buildings, outdoor sites and even housing estates. Another usage of car type and color recognition is when a certain model of car is being investigated in highways and streets. In this thesis two independent systems are designed; one for car type recognition and another for car color recognition. They both require to know the license plate location, so we proposed a license plate detection system. In the license plate detection system, first the plate candidates are extracted from image by gradient and morphological operations, then...
Some Results and Conjectures on Bounds for Graph Colorings
, M.Sc. Thesis Sharif University of Technology ; Mahmoodian, Ebadollah (Supervisor)
Abstract
There are many ways to color the vertices and edges of graphs, such as, rainbow connection, vertex coloring and dynamic coloring. In this thesis, in Chapter 1 we introduce a new coloring, we consider its relationship with some other colorings and we investigate its computational complexity. In chapter 1, we focus on the proper orientation number. The problem of orienting the edges of a given simple graph so that the maximum indegree of vertices is minimized was introduced in 2004. We show that there is a polynomial time algorithm for determining the proper orientation number of a given 3-regular graph. But it is NP-complete to decide if the proper orientation number of a 4-regular graph is 3...
[r; s; t]-Coloring of Graphs
, M.Sc. Thesis Sharif University of Technology ; Mahmoodian, Ebadollah (Supervisor)
Abstract
Graph coloring is an important concept in graph theory. There have been much developments in this concept recently, vertex coloring, edge coloring and total coloring are studied. But one of the newest kind of graph coloring is [r; s; t] -coloring. This coloring is introduced in 2003 by A. Kemnitz and M. Marangio. In this coloring the difference of any two adjecent vertices, any two adjecent edges, and any adjecent vertex and edge must be at least r, s and t respectively. In this thesis we study [r; s; t] -coloring of graphs and discuss about its results
An Efficient Algorithm for Graph Sum Coloring Problem
, M.Sc. Thesis Sharif University of Technology ; Eshghi, Kourosh (Supervisor)
Abstract
Graph sum coloring problem is a special case of graph vertex coloring. Because of its applications in practical areas, especially in scheduling, many researchers have been attracted to it. In recent years, several heuristic and metaheuristic algorithms were applied to sum coloring problem. In this research a heuristic algorithm based on mini-max ant system and simulated annealing metaheuristics is used for graph sum coloring problem. This algorithm is tested on random graphs used in the literature and compared with prior algorithms. Results show that in many cases our proposed algorithm reaches the best known results or improves them
Harmonious Coloring of Graph
, M.Sc. Thesis Sharif University of Technology ; Jafari, Amir (Supervisor)
Abstract
Let G be a simple graph. A harmonious coloring of G is a proper vertex coloring such that each pair of colors appears together on at most one edge. The harmonious chromatic number, h(G), is the least number of colors in such a coloring. In this project, first we discuss about complexity of harmonious coloring. Then we find some bounds for harmonious chromatic number
Sequential Coloring of Graphs and Function Simulation
, M.Sc. Thesis Sharif University of Technology ; Daneshgar, Amir (Supervisor)
Abstract
Sequential coloring of graphs was first introduced by Tucker in [Tucker (1983)] to study perfect graphs, and was subsequently studied from a number of different perspectives, such as its connections to uniquely colorable graphs. In this thesis we begin by introducing the version of sequential coloring of graphs defined by [Daneshgar and Ebrahimi (2008)], and after surveying their results concerning the defining sets of sequential coloring of graphs, and also surveying the results obtained by [Daneshgar, Rahimi and Taati (2010)] and [Daneshgar, Hajiabolhassan and Taati (2010)] regarding the simulation of functions using sequential coloring of graphs, we turn to the reduction systems that can...
Kinetic Investigation of the Degradation of Environmental Pollutant in the Presence of TiO2 Nanoparticle on Carbon Nanotube
, M.Sc. Thesis Sharif University of Technology ; Gholami, Mohammad Reza (Supervisor) ; Rahman Setayesh, Shahrbanoo (Co-Advisor)
Abstract
The present work is based on the, synthesis and investigation of photocatalytic activity of TiO2, TiO2/MWCNT, ZnO and ZnO/MWCNT nanostructures. The nanostructures were prepared using multi-walled carbonnanotubes (MWCNT) as templates.The SEM images of TiO2 and ZnO nanoparticles and TiO2/MWCNT andZnO/MWCNT showed that nanosize TiO2 and ZnO particles homogeneously and densely supported on the surfaces of multiwall carbon nanotubes the photocatalytic activity of the TiO2, TiO2 /MWCNT, ZnO and ZnO/MWCNT was examined by the degradation of Basic Blue 41(BB41) under UV and Vis lights. The optimum conditions for degradation of BB41 on TiO2 where found to be: calcination temperature (450 °C), dye...
Zero-divisor Graphs of Partially Ordered Sets
, M.Sc. Thesis Sharif University of Technology ; Pournaki, Mohammad Reza (Supervisor)
Abstract
Let (P;≼) be a partially ordered set (poset, briefly) with a least element 0. In this thesis, we deal with zero-divisor graphs of posets. We show that if the chromatic number r(P) and the clique number r(P) (x(r(P)) and !(r(P)), respectively) are finite, then x(r(P)) = !(w(P)) = n in which n is the number of minimal prime ideals of P. We also prove that the diameter of such a graph is either 1, 2 or 3 while its girth is either 3, 4 or 1
The Zerodivisor Graph of a Qoset
, M.Sc. Thesis Sharif University of Technology ; Pournaki, Mohammad Reza (Supervisor)
Abstract
We study colorings of quasiordered sets (qosets) with a least element 0. To any qoset Q with 0 we assign a graph (called a zerodivisor graph) whose vertices are labelled by the elements of Q with two vertices x; y adjacent if the only elements lying below x and y are those lying below 0. We prove that for such graphs, the chromatic number and the clique number coincide
Online Conflict-free Coloring Of Intervals
, M.Sc. Thesis Sharif University of Technology ; Abam, Mohammad Ali (Supervisor)
Abstract
In this thesis, we consider the problem of online conflict-free coloring for regions. First, we analyze online variant of the conflict-free coloring of intervals on the line, where each newly inserted interval must be assigned a color upon insertion such that the coloring remains conflict-free, i.e. for every point p in the union of the current intervals, there must be an interval I with a unique color among all intervals covering p. we present deterministic algorithm for achieving this goal which uses O(log^3n) color. Next, we consider the online conflict-free coloring of nearly-equal axis-parallel rectangles in the plane and present a deterministic algorithms which uses O(log^12n)...
On Beck’s Coloring of Posets
, M.Sc. Thesis Sharif University of Technology ; Pournaki, Mohammad Reza (Supervisor)
Abstract
We study Beck-like coloring of partially ordered sets (posets) with a least element 0. To any poset P with 0 we assign a graph (called a zero-divisor graph) whose vertices are labelled by the elements of P with two vertices x, y adjacent if 0 is the only element lying below x and y. We prove that for such graphs, the chromatic number and the clique number coincide.Also, we give a condition under which posets are not finitely colorable
Hypercubes and Some of their Problems
, M.Sc. Thesis Sharif University of Technology ; Mahmoodian, Ebadollah (Supervisor)
Abstract
There is much interest in the theoretical study of the structure of hypercubes because their structure has played an important role in the development of parallel processing and is still quite popular and influential.This thesis will begin with an introduction to hypercubes and some of their problems. Then we study the following concepts: Arboricity (The minimum number of edge-disjoint forests into which a graph can be decomposed), Galactic number (similar to arboricity but such that each component of each forest is a star), Silver coloring (Given a set I of maximal independent vertices, a silver coloring with respect to I is such that every v 2 I sees every other colors in its closed...
Twin Edge Coloring of Graphs
, M.Sc. Thesis Sharif University of Technology ; Akbari, Saeed (Supervisor)
Abstract
Let G be a graph. A twin edge k-coloring of G is a proper edge coloring of G with the elements of Z_k so that for every vertex u and v of G we have s(u)≠s(v), where s(u) is the sum of all colors of the edges incident with u. The minimum k for which G has a twin edge k-coloring is called twin chromatic index of G and denoted by χ_t^' (G). In this thesis we find the chromatic index of paths, cycles, complete graphs, complete bipartite graphs and some complete tripartite graphs. In 2014 it was conjectured that if G is a connected graph with at least 3 vertices and maximum degree Δ(G), then χ_t^' (G)≤Δ(G)+3
Colorings of Latin Square Graphs and Block Designs
, M.Sc. Thesis Sharif University of Technology ; Mortezaeefar, Masood (Supervisor)
Abstract
In the first part of this thesis we study Latin Square Graphs defined as follows: to each cell of a latin square L of order n we associate a vertex of the graph (which we call L3(n)) with two vertices u and v adjacent if and only if their respective cells are in the same row or column or contain the same symbol. We investigate the coloring problem associated with these graphs and explore the relationship between this problem and some other combinatorial objects such as strongly regular graphs and transversals and obtain some upper bounds. We use a computer search to find the chromatic number of all latin squares of order less than 8. We determine the chromatic number of some special classes...
Photocatalytic Dye Degradation of Wastewater Using Copper Composite Nanophotocatalyst by Advanced Oxidation Process
, M.Sc. Thesis Sharif University of Technology ; Ghotbi, Cyrus (Supervisor) ; Mahmoodi, Niyaz Mohammad (Supervisor) ; Kazemeyni, Mohammad (Supervisor)
Abstract
Azo dyes that are the most common dyes in textile industries, are toxic and stable complex compounds. Release of this dyes in environment disturb the ecosystem and endanger human health. So selection of an appropriate method for treatment of them is a sensitive work. photocatalytic degradation is one of the best promising methods because of its perfect mineralization, middle condition and lack of creating the secondary pollutant. In this research CuO/CNT nanocomposite was synthesized and used as a photocatalyst. The surface features of CuO/CNT were surveyed by using Fourier transform infrared(FTIR), X-ray diffraction (XRD) and Scanning electron microscopy (SEM). Photocatalytic efficiency of...
Conflict-free Coloring with Recoloring
, M.Sc. Thesis Sharif University of Technology ; Abam, Mohammad Ali (Supervisor)
Abstract
A coloring of regions is conflict-free if for any covered point in the plane, there exist a region that cover it, with a unique color. In this thesis, we examine the problem of conflict-free coloring of regions in dynamic model, with minimum colors, and with the possibility of recoloring the optimal numbers of colored regions. That means, regions are inserted one by one on the plane, and by inserting any region, inserted regions shall be conflict-free. Dynamic model are divided into three categories: offline model, online with absolute positions model and online with relative positions model. The difference between these three categories is in the information contained in insertion of...
Computing Fundamental Colored Graph Properties in Sublinear Time
, M.Sc. Thesis Sharif University of Technology ; Abam, Mohammad Ali (Supervisor)
Abstract
Because of growing amount of data which communicated across the world, analyzing massive data set becomes more important than ever. The graph structure as an important and broadly used data structure is much more important than others. In this thesis, besides introducing the sublinear time algorithm model for massive data as a very efficient and superfast method to deal with massive data, we use them to solve problems for colored graphs. As a fundamental property, we try to compute the average of colored degree. This problem is analyzed from different aspects with various limitation. Two algorithms with multiplicative approximation factor, based on the average degree of simple graphs are...
Conflict-free Chromatic Art Gallery Covering with Vertex Guards
, M.Sc. Thesis Sharif University of Technology ; Ghodsi, Mohammad (Supervisor)
Abstract
The visibility is one of the most important problems in computational geometry. Two points are said to be visible to each other, if the line segment that joins them does not intersect any obstacles. The art gallery problem is a well-studied visibility problem in computational geometry. It originates from a real-world problem of guarding an art gallery with the minimum number of guards who together can observe the whole gallery. In many of applications, the “guards” are “landmarks” deployed in an environment to help provide navigation and localization service to mobile robots. The mobile device communicates with these landmarks through wireless, or other “line-of-sight” signaling...