Sharif Digital Repository

Web is one of the biggest sources of information. The tremendous size, the dynamicity, and the structure of the Web have made the information retrieval process of the web a challenging issue. Web Search Engines (WSEs) have started to help users with this matter. However, these types of application, to perform more effectively, always need current information about many characteristics of the Web. To determine these characteristics, one way is to use statistical sampling of the Web pages. In this kind of approaches, instead of analyzing a large number of Web pages, a rather smaller and more uniform set of Web pages is used. This research attempts to analyze the presented methods for... 

Mobile Ad hoc Networks (MANETs) are based on the assumption of that all participants in the network cooperate and forward packets towards the destinations. However, due to the limited nature of the nodes' resources, a node may decide not to cooperate to save its resources while still using the network. Such behavior of some nodes may degrade the whole network performance. To cope with such a situation, we propose a Stable path, Low overhead, Truthful, and Cost efficient (SLTC) routing protocol which stimulates nodes to cooperate. SLTC utilizes the game theoretic notion of mechanism design. To the best of our knowledge, SLTC is the first protocol attaining the message complexity of O(nd),... 

In New applications of Mobile Ad hoc Networks (MANETs), nodes may decide not to cooperate in routing protocols in order to save their limited resources while still using the network to relay their own traffic. Exhibiting such a selfish behavior by even a few nodes may degrade network performance and other cooperating nodes may find themselves unfairly loaded. To cope with such a situation, we propose a Stable path, Low overhead, Truthful, and Cost efficient (SLTC) routing protocol which stimulates nodes to cooperate and act truthfully by utilizing the game theoretic notion of mechanism design. To the best of our knowledge, SLTC is the first protocol attaining the message complexity of O(nd),... 

Vivid banding pattern of the chromosome image is a crucial part for diagnosis in karyotype medical test. Furthermore, thriving computer aided segmentation and classification depend on the initial image quality. In this paper, we propose an adaptive and iterative histogram matching algorithm for chromosome contrast enhancement especially in banding patterns which is one of the most important information laid in chromosome image. Objective histogram, with which the initial image needs to be matched, is created based on processes on the initial image histogram. Calculation of statistical moments of image histogram and determination of parameters in each step of iteration based on these moments... 

Vivid banding patterns in medical images of chromosomes are a vital feature for karyotyping and chromosome classification. The chromosome image quality may be degraded by many phenomenon such as staining, sample defectness and imaging conditions. Thus, an image enhancement processing algorithm is needed before classification of chromosomes. In this paper, we propose an adaptive and iterative histogram matching (AIHM) algorithm for chromosome contrast enhancement especially in banding patterns. The reference histogram, with which the initial image needs to be matched, is created based on some processes on the initial image histogram. Usage of raw information in the histogram of initial image... 

Human Brain is one of the most wonderful and complex systems which is designed for ever; A huge complex network composed of neurons as tiny biological and chemical processors which are distributed and work together as a super parallel system to do control and vital activities of human body. Brain learning simulation and hardware implementation is one of the most interesting research areas in order to make artificial brain. One of the researches in this area is Active Learning Method in brief ALM. ALM is an adaptive recursive fuzzy learning algorithm based on brain functionality and specification which models a complex Multi Input Multi Output System as a fuzzy combination of Single Input... 

Lake Urmia in northwestern Iran is the largest lake in Iran and the second largest saltwater lake in the world. The water level in Lake Urmia has decreased dramatically in recent years, due to drought, climate change, and the overuse of water resources for irrigation. This shrinking of the lake may affect local climate conditions, assuming that the lake itself affects the local climate. In this study, we quantified the lake's impact on the local climate by analyzing hourly time series of data on climate variables (temperature, vapor pressure, relative humidity, evaporation, and dewpoint temperature for all seasons, and local lake/land breezes in summer) for the period 1961-2016. For this, we... 

Vulnerabilities are now part of all software systems. To handle vulnerabilities, many approaches have been proposed till now. Many of these approaches try to analyze vulnerabilities based on model checking techniques. However, the models used in these approaches handle authorized and unauthorized rules separately. This basically cause in weaker modeling abilities and consequently weaker vulnerability analysis. From authorized and unauthorized rules, we mean those emanated from access control model and those originated from vulnerabilities respectively. Currently, a new general graph-based protection system concentrating on vulnerabilities called VGBPS is proposed to overcome the mentioned...