Sharif Digital Repository

Graph coloring is a fundamental problem in Computer Science. Despite its status as a computationally hard problem, it is still an active area of research. Depending on the specific area of requirement or an pplication, there are several variants of coloring.One such variant of graph coloring is Acyclic Graph Coloring. As with the case of proper coloring of graphs, Acyclic coloring can either be on vertex set or the edge set of a graph. When such a coloring is performed on the edges of a graph, it requires that after a graph has been colored there should not exist any cycle that runs on edges that are colored by only two colors. Such a cycle is called a bichromatic cycle. When a coloring does... 

Critical sets and defining sets in combinatorics have been attended by mathematics fans. These subjects have been debated since 1997 and a lot of researches have been done about them and a lot of articles have been published. But number of unsolved questions might be more than answered questions. In these years critical sets for Latin square and defining sets for vertex coloring have been attended and also enough researches about issues related to defining sets for edge coloring and total coloring have not been done. For these reasons we focus on these issues in this thesis. Issues like defining sets for edge coloring and total coloring in complete graphs, generalized Petersen graphs and also... 

The corrosion rate of steel (EN 10130 DC-04) in the presence of oleuropein in aqueous corrosive solutions (of different concentrations in 1M and 0.5M hydrochloric acid and also 3.5% sodium chloride) evaluated and results was shown that oleuropein can protect steel surfaces and it acts as good inhibitor. This means that the observations of linear polarization and weight loss experiments showed inhibitor efficiency more than 97% in acidic corrosive medium and above 74% for aqueous solution of 3.5% sodium chloride. Adding oleuropein at different concentrations (i.e. 300 ppm, 700 ppm, and 1000 ppm) to three different types of polymeric paint structures (nitrocellulose alkyd base, acrylic base,... 

Over the past years, translating a grayscale image to a colorful image, due to its applications in medical imaging, and restoring and colorizing old images, has been popular. The problem we are studying here is automatic grayscale image translation to a colorized image such that the colorized image appears as real as possible. Due to the large degrees of freedom in the allocation of colors to different sections of a grayscale image, this problem is extremely ill-posed. Hence, based on previous works we attempt to utilize Generative Adversarial Networks and Convolutional Neural Networks to overcome this issue. The trained model receives a grayscale image and predicts two chromatic channels of...