Sharif Digital Repository

Trust is a common concept in interpersonal relationships. It is a replacement for strict control mechanisms, helping individuals to have a better estimation of the risks involved in an interaction or relationship. Computational notions of trust have a close relationship with security in computer systems.Different models of trust have been proposed to regulate interactions in: security, collaborative systems, and routing. We focused on two important problems and challenges in this dissertation: proper handling of uncertainty, and uncertainty-aware trust-based decision-making.We propose an integrated approach to modeling, processing, and treating uncertainty, as well as to uncertainty-aware... 

Resource sharing is the most important feature of a Grid. Resource discovery enables users to find the most suitable resources to run Grid jobs on. Resource discovery systems are often centralized or hierarchical. These structures are usually prone to a single point of failure, and unbalanced distribution of processing and storage load, making them inefficient as the Grid grows. These challenges have led researchers to adapt distributed approaches, such as Peer-to-Peer file sharing solutions. The important differences between Grid resource discovery and P2P file discovery (e.g. different resource attributes, queries, change patterns etc.) make it difficult to port the existing solutions to... 

In recent years the rapid rise of polymer consumption especially in the form of packaging materials became a real menace for the environment. Polyolefin are some of the most dominant packaging materials and responsible by part of the problems in the disposal of one-trip packaging. One of the possible ways of solving this problem is the introduction of additives increasing their susceptibility to environmental degradation into non-biodegradable polymers. One such additive is starch- the natural, cheap, and easily biodegradable polymer. Starch was already used as a filler or as a blend with polyolefin. Addition of dry starch granules to polyolefin follows the general trend of filler effects on... 

Skin tissue engineering, is considered as a method to heal full-thickness wounds. The basis of this method is fabrication a substrate named scaffold in order to replace the lost skin tissue temporarily. The aim of the present study is the fabrication and characterization of skin scaffolds using two natural polymers, which are Chitosan and Gelatin. This study is divided into three phases: first is the investigation of the influence of two cross-linkers named Glutaraldehyde and a kind of carbodiimide on the properties of scaffolds, second is the characterization of scaffolds fabricated by three different ratios of chitosan/gelatin and third is the evaluation of the effect of Allantoin on... 

Circulating tumor cells (CTCs) are cancer cells which shed from the primary tumor, enter circulation and spread cancer all over the body. CTCs give valuable information about cancer and can help diagnosis and prognosis. Hence separating and isolating CTCs from blood is a necessity for cancer therapeutics. CTCs are separated from blood cells by their different physical or biochemical properties. Many groups have attempted different methods for separation of CTCs. Inertial microfluidics is one of the newest approaches in CTC separation technologies which separates CTCs based on their size. Current inertial microfluidic systems containing straight, spiral, serpentine and contraction expansion...