primary and widely in use computed tomography (ct) dose descriptor is a volumetric ct dose index (ctdiv) that is usually measured by a pencil ionization chamber with active length of 100mm and polymethyl methacrylate (pmma) phantom. ctdiv depends on scan parameters such as mas, kv, collimation, tube rotation time but is independent of patient’s size and shape. for the purpose of a good estimati...

technology advancement improves the way we interact with computer systems. keyboard, mouse, and touchpad provide an easier and more natural way of interaction with a computer system. nowadays, by introducing low cost and high performance depth cameras like kinect and xtion, new opportunities are available for creating even more natural interfaces. in this paper, a new model was demonstrated for...

 Recommender systems are a branch of retrieval systems and information matching, which through identifying the interests and requires of the user, help the users achieve the desired information or service through a massive selection of choices. In recent years, the recommender systems apply describing information in the terms of the user, such as location, time, and task, in order to produce re...

web usage mining (wum) is the automatic discovering of hidden informationof user access pattern from the web log data. frequent pattern discovery is one ofthe main techniques in wum that can be used to implement recommender systems,forecast user`s navigational behaviour, and personalize web sites. many algorithmshave been suggested on obtaining frequent user navigation patterns. this paperprese...

Web search engines are one of the most popular tools on the Internet which are widely-used by expert and novice users. Constructing an adequate query which represents the best specification of users’ information need to the search engine is an important concern of web users. Query expansion is a way to reduce this concern and increase user satisfaction. In this paper, a new method of query expa...

recommender systems utilize information retrieval and machine learning techniques for filtering information and can predict whether a user would like an unseen item. user similarity measurement plays an important role in collaborative filtering based recommender systems. in order to improve accuracy of traditional user based collaborative filtering techniques under new user cold-start problem a...