Sahand MozaffariBachelor of science student
in Computer Engineering Department
of Sharif University of Technology
My name is Sahand Mozaffari, natively written سهند مظفری and pronounced sæhænd mozæfæɾiː. I was born on October 21st, 1993 in Iran. Since September 2011 I have been a B.S. student of software engineering in computer engineering department of Sharif University of Technology, a highly prestigious university of my home country. I took on a second major, theoretical mathematics, in 2013 to fulfill my passion for mathematics. I am expected to receive my B.S. degrees by summer of 2016. Along with my education, I have been spending time on research on diverse subjects in computer science. With that experience behind, I have chosen to continue my studies in the field of algorithm design and analysis.
Let G be a graph. A total dominating set of G is a set S of vertices of G such that every vertex is adjacent to at least one vertex in S. The total domatic number of a graph is the maximum number of total dominating sets which partition the vertex set of G. In this paper we provide a criterion under which a cubic graph has total domatic number at least two.
Büchi automaton of records (BAR) has been proposed as a basic operational semantics for Reo coordination language. It is an extension of Büchi automaton by using a set of records as its alphabet or transition labels. Records are used to express the synchrony between the externally visible actions of coordinated components modeled by BARs. The main composition operator on the set of BARs is called as join which is the semantics of its counterpart in Reo. In this paper, we define the notion of labeled transition systems of records as a generalization of the notion of BAR, abstracting away from acceptance or rejection of strings. Then, we consider four equivalence relations (semantics) over the set of labeled transition systems of records and investigate their congruency with respect to the join composition operator. In fact, we prove that the finite-traces-based, infinite-traces-based, and nondeterministic finite automata (NFA)-based equivalence relations all are congruence relations over the set of all labeled transition systems of records with respect to the join operation. However, the equivalence relation using Büchi acceptance condition is not so. In addition, using these results, we introduce the language-theoretic definitions of the join operation considering both finite and infinite strings notions. Also, we show that there is no language-based and structure-independent definition of the join operation on Büchi automata of records.
In this thesis, we discuss the facility location problem in two dimensional space. Facility location problem, also known as k-center problem, is of great importance in computational geometry, operational research and data mining fields. The goal in this problem is to find an optimum placement for k facilities on the plane, such that the cost for clients traveling to the nearest facility is minimized. Solving this problem in presence of outlier points has interested many researchers in recent years.
In this article, having explained the previous works on this subject, we present new algorithms for k-center problem with weighted outliers.