Sharif Digital Repository

Traditional classification techniques of machine learning assume that data have stationary distributions. This assumption for recent challenges where tremendous amount of data are generated at unprecedented rates with evolving patterns, is not true anymore. Classification of data streams has become an important area of machine learning, as the number of applications facing these challenges increases. Examples of such data streams applications include text streams, surveillance video streams, credit card fraud detection, market basket analysis, information filtering, computer security, etc. An appropriate method for such problems should adapt to drifting concepts by revising and refining the... 

Mixed-criticality embedded systems, as the next-generation of safety-critical systems, are increasingly employed in industry due to consolidating functionalities with varying criticality levels onto the same computing platform. Also, cost reduction and performance improvement encourage adoption of multicore platforms in these systems. Technology scaling, battery-supplied design and heavy computation in mixed-criticality systems necessitates employing energy management techniques. Due to the degrading effects of these techniques on the system’s reliability, reducing energy consumption without sacrificing the reliability requirement is a vital challenge in mixed-criticality systems, in... 

Duplex stainless steels and advanced high strength steels are both known as new materials in automobile industry applications. Process of resistance spot welding is the main process in welding of auto-body structures. Hence investigating the welding metallurgy and weldability of similar and dissimilar joints of duplex stainless steels and advanced high strength steel are crucial. The purpose of this study is to analyse the relationship between welding process and geometric characteristic of weld nugget, phase transformations of Weld nugget and heat affected zone, mechanical properties (i.e force bearing capacity and energy absorption capability) and failure mode (interfatial or pullout). in... 

Isn’t our universe ,which includes everything that is causally connected to us, a tiny and negligible part of wider and diverse “multiple universes”? Although the multiverse idea has been considered by scientists recently, it had been discussed by philosophers and theologians in the past.
Many of our physical theories,whether being accepted like General Relativity, or speculative like string theory, lead naturally to the multiverse idea .The idea of multiverse is also brought forth to take care of the fine tuning observed in cosmology, in connection with the so – called anthropic principle.
This idea appeared in order to answer to some problems of quantum mechanics, string theory... 

Passive wideband reconnaissance receivers, listen to the radio and radar signals in the environment and estimate their important parameters such as direction of arrival (DOA). The wideband attribute for these receivers is to refer to their ability to receive wideband signals.Due to the use of processing gain, LPI radars reduce their transmitted signal power to see and not to be seen. On the other hand reconnaissance receivers can not have much processing gain, because they do not know the nature of the transmitted signal; Therefore, to increase the operational range of these systems, it is necessary to increase the signal to noise power ratio (SNR). This thesis examines the use of antenna... 

About a century, “Eye Tracking” has been studied, and it has two definitions: • The process of measuring the point of gaze (where one is looking). • The process of measuring the motion of an eye relative to the head. Eye tracking technology has been used in many fields such as psychology. However, applications of this technology has been recently considered in marketing, computer interfacing, entertainment, training and so forth. Since pupil is a distinc area in eye images, pupil detection is one of the effective solutions of eye tracking. In most of the pupil detection approaches, the edge points of the pupil contour are detected firstly, and then the optimal ellipse is fitted to them....