Sharif Digital Repository

In this project, an online controller design method based on parameter optimization is presented. The structure of controller is chosen to be the Internal Model Control (IMC). The cost function and constraints which include both time domain and frequency domain functionals are calculated directly from measurements of system’s output in order to reduce the effect of uncertainty in model estimation and controller design. The controller design problem is formulated as a convex optimization problem with ellipsoid algorithm used for its solution. The model of the system and a worst case upper bound on remaining uncertainty in model due to measurement noise, along with unmodeled dynamics of the... 

Web service technology is becoming increasingly popular since it is very bene?cial in di?erent types of applications. Due to a dramatical increase in the number of developed web services, the service discovery process has become crucial for using web services e?ciently. Service is an adaptive, self-describing, modular application, which may be used in either web or an internal network. Service providers should o?er the services along with a description ?le called advertisement explaining the speci?cations and functionalities of the service. Traditional service discovery methods are based on syntax and keyword matching, which may not satisfy the requester’s desired requirements and will... 

Web services are some kind of software applications which are available on the Web. Growing the popularity of Web services, led to increasing number of providers and as a result a great deal of Web services. This huge number of services made the searching and discovery tasks hard and effort-full jobs. In order to have a better discovery it is better to first classify Web services into some categories and then search in the relevant class. Although this classification can be done based on matching key words through the service registration information, such syntax-level service facilities can’t achieve the satisfaction results both in the precision and the recall sides. Human experience shows... 

Communications in organizations have been one of the most important issues. To run the business processes, the company needs communication between units and customers. We provide a tool which can be used as an aid for network designers by guiding them with a framework. The resulting QoS parameters help to provide more alignment between the network and business requirements. The framework contains values for delay, loss and availability as three QoS parameters of the network used in the business process. The organizations business processes are used as a basis for the method which used in the tool. We use UML as the tool to model the business processes in the organization and the process is... 

With the development of social network sites and wide use of Social Networks, information security and confidence of its components, became more and more important and turned into subject of many studies and researches. Relationship based on trust besides increasing productivity reduces risk of information transmission to non-related people. Although in the real world, semantic relations are the main basics for trust, but the existing methods of trusting in current sites have less attention to this point. To reduce such issues, firstly this research is going to use an added semantic understanding on top of the social networks structure. To do so, there is an inference engine in addition to a... 

Nowadays, in our contemporary societies the social networks and online communities have carved for themselves a crucial niche and unique status. Maintaining and enhancing a core relation between their communities, thus have proven to be a worthy challenge to IT professionals. We have proposed a model for developing and maintaining a cohesive relation between members in social networks and improved their interaction and cooperation via collaboration of different social networks .We focus on the definition and properties of transitivity and semantic attributes ,which explains the relationship between members’ attributes and their membership level in social networks and leading us to provide... 

Social network is a map of relationships among individuals or organizations. With the development of social network sites (SNS), security protection of private information online has been a serious and important research topic. Information in social networks is online all the time and available to a large number of visitors. The main problem in current SNSs is that, people are not able to define different categories for their relations and then they cannot have good self-defined privacy policies. Also default policies cannot satisfy different environments and cultures and will serve information to strangers. After that different social networks with different interfaces are not... 

In the modern world of software engineering, software evaluation has earned a special position. The presence of consultation companies in evaluating the software will confirm this specialty. Web technology, as a new trend in computer science, has attracted the attention of many researchers and practitioners. As known nowadays, most of the software solutions are Web-based. Such software is technically called Web application. The methods of evaluating Web application include the use of traditional metrics in software engineering. The intelligence of the Web in computer science has been the core of much research.
This study is intended to use intelligence, as one of the new features of the... 

Networked computers are expanding more and more around the world, and digital social networks becoming of great importance for many people's work and leisure. Emails, Weblogs and Instant Messengers are popular instances of social networks. In this thesis, the main target is to have an advertisement according to user favorites and interests by mining his/her interactions in digital social networks. Briefly, in our method social network users are categorized based on the topics exchanges between them in the network, these topics discovered by mining of flowing data in that environment, considering that these topics shows the user willing, finally relevant advertisements will be represented to... 

One of the novel methods of stabilization of nuclear waste is the use of vitrification technology. In order to stabilize high level wastes (HLLW) in glass, it is required that the elements are in their oxide form. Therefore, it is necessary to evaporate the waste and turn it into a solid form so that the elements can be converted into oxide form in the calcination furnace. Hence, one of the challenges of stabilization is the optimization of evaporation and calcination conditions. In this research, the parameters affecting evaporation were first investigated. Using laboratory measurements of application: temperature (110 to 180 °C), presence of nitric acid (0.5 to 4 mol/L), ratio of zirconium... 

This study used the emulsion liquid membrane method to investigate the extraction and separation of thorium from nitrate solution. According to the results obtained from the studies, Cyanex 272 was a suitable option for selectively extracting thorium. For simultaneous extraction and stripping of thorium from dilute aqueous solutions, an emulsion liquid membrane system consisting of Cyanex 272 as an extractant, Span 80 as a surfactant and sulfuric acid solution as a receiving phase (internal phase) was used. Emulsion liquid membrane method has high mass transfer flux due to high surface to volume ratio, which causes high extraction efficiency and fast transfer of thorium ions from its low... 

One of the most common spinal surgeries involves spinal fusion or vertebral fixation, which is used to treat various conditions such as intervertebral disc disease, scoliosis (lateral deviation of the spinal column), fractures, infections, or the presence of tumors in the spinal column. In this surgical procedure, the use of pedicle screws and titanium rods prevents motion and friction between two vertebrae. Screws may enter the vertebrae in the wrong position and angle, causing bone weakening, rupture of nerve roots or blood vessels, weakness or lack of sensation in some parts of the body, spinal cord injury, and in severe cases, paralysis of the patient. For this reason, fusion surgery is... 

Nowadays trust has become one of the main challenges of every online social network. The open and decentralized nature of Peer-to-Peer network makes it vulnerable to be exploited by malicious users to distribute tampered and harmful contents. We propose a dynamic computational trust model based on a neuro-fuzzy approach and implemented it on Gnutella network. The model is a novel application of control systems approach for evaluating trust and reputation in P2P networks. We utilize Local Linear Model Tree (LOLIMOT) to perform a nonlinear dynamic system identiffcation and thus to approximate trust. The performance of our reputation-based trust model is evaluated by simulation. We create a... 

Lithium is a soft, silvery-white alkali metal that is recognized as the lightest metal and the least dense solid element. The increasing demand for lithium, driven by the global shift towards electrification and sustainable energy solutions, has transformed this material into a crucial resource in the modern economy. Lithium has applications in various industries, including the nuclear industry. 6Li is used for the production of tritium, and 7Li, in the form of 7LiOH, is used to adjust the pH in light water reactors and as an anti-corrosion compound in fission reactors. In this study, the extraction of lithium from the aqueous phase using a Y-shaped microchannel was carried out, and the mass... 

In recent years, due to urban expansion and population growth, number of floors and excavations depth has increased. Stabilization of excavations is one of the most important issues in geotechnical engineering. Today, one of the most widely used methods that is used in deep excavations is brace soil by steels and pretension them. In this thesis tries to evaluate static behavior of flexible supporting structures with pretension anchors by using PLAXIS2D, FLAC3D and GEOSTUDIO softwares. The objective of this modeling is better understanding the static behavior of walls, comparing the two and three dimensional modeling and the effect of corners of excavation on deformation. The results shows...