Sharif Digital Repository

In this study, hot extrusion of AA6061-%5 SiCp composite has been predicted and flow behavior of material during deformation process has been investigated. At the first step, hot compression tests have been carried out to obtain the flow behavior of the material at different temperatures and strain rates. In the next step, an FE-based temperature-displacement coupled model by employing ABAQUS software has been proposed in order to solve the energy and heat transfer equations and to determine the required energy and force for the extrusion process. Experimental investigations have also been performed to verify the proposed model. Comparison between the results from the model and the... 

The Use of peer-to-peer architectures instead of traditional client-server architecture can be beneficial in many aspects such as increasing scalability of the systems, enhancing fault tolerance in critical situations, extending the system resources and various other advantages. Nowadays, many applications are based on peer-to-peer architectures and as a result, a large portion of the internet traffic is produced by these applications. This has been a motivation to many researchers to focus on reducing the amount of this traffic while satisfying the content distribution demands. One of the main problems that can result in generating large amount of traffic and also long response times for... 

In today’s competitive world، web services have become more and more prevalent and their efficient discovery and composition in order to create novel functionalities is essential for variety of applications. Due to the large number of available services، the discovery of services is a difficult and time consuming task. Existing approaches in web services discovery and composition attempt to use simple web services while ignoring the use of once composed services. Reusing frequently used composite services can considerably increase performance of the entire system. Moreover، the advent of semantic web، as an effective solution of representing information interpretable by machines and none... 

Nowadays, the essentiality of appropriate modeling languages has become evident, and with the introduction of new concepts such as domain-specific languages, the need for systematic research on designing and engineering new modeling languages has increased significantly. Several modeling languages have been developed and employed over the years, but the area of modeling languages still suffers from the lack of a proper framework: There is a strong need for an engineering framework that specifies the detailed steps of language development, the input and output artifacts of each step, the techniques applicable to each step, and quantifiable methods for quality measurement. From a unified point... 

Peer-to-peer (P2P) computing is a popular distributed computing paradigm for many applications which in-volve exchange of information among a large number of peers. In such applications, large amount of data is distributed among multiple dispersed sources. Therefore, data analysis is challenging due to processing, storage and transmission costs. Moreover, the data rarely remains static and frequent data changes, quickly out date previously extracted data mining models. Distributed data mining deals with the problem of data analysis in environments with distributed data and computing resources. In this dissertation, we explore distributed data mining in different structures of P2P systems. In... 

Software Product Line is known as a process of developing family of the software together. The methods of building a software product line is trying to capture commonality and variety of this family of software and form a product line based on them. Commonality of this family of the software allows us reuse in every aspect of the development of software. Nowadays, software architecture as a one of the most important aspect of software engineering, plays major role in specifying the tasks and clearing the relationship between people. It can divide large and complex system to some sub-system and overcome complexity of the system. Software architecture forms a basis for communication among... 

Automation of the software development process is the software engineers' final goal, but with the current facilities and knowledge in software engineering, it is not possible to automatically generate the whole software. Usually all the software in a specific domain contain common behaviors, which by careful exploration of these common behaviors and automation of code generation in these sections, the cost and time of projects' execution can be reduced. According to Model Driven Development (MDD), the first step in software development is creating appropriate models. For creating models, metamodel is required; therefore, we need to create a specific motamodel for the chosen domain or use... 

One of approaches in software architecture design is using architecture styles or patterns. This approach is a suitable way for satisfying functional and nonfunctional requirements and also is cost effective. It is shown that this approach improves effectively quality of software systems. Whereas, choosing a suitability architecture style for complex designs depends on many factors and often one style cannot meet all the requirements, therefore, use of heterogeneous styles can be useful. Also, in software product line architecture design, we must combine different kinds of architectural styles to cover the problem domain and achieve better performance. Correct and accurate choice of... 

Nowadays, there exist many real networks with distinctive features in comparison with random networks. Social networks, collaboration networks, citation networks, protein networks and communication networks are some example of complex network classes. Nowadays these networks are widespread and have many applications and the study of complex networks is an important research area. In many applications, the “synthetic networks generation” is one of the first levels of complex networks analysis. This level has many applications such as simulation and extrapolation. Many generative models are proposed for complex network modeling in recent years. By the use of these models, synthetic networks... 

Due to the increase in size and complexity of software systems, choosing suitable software architecture is a fundamental issue. One of the most effective ways for designing and valuating software architectures is to adopt architectural styles. An architectural style is an approach for reaping the benefits of similarities that exist between various architectures. Adoption of architectural styles in the design process of a software system assures the employment of strength points of specifications that belong to each architectural style. However, selecting a suitable architectural style depends on different criteria. Therefore it makes the ... 

The development of a complex software needs an abstraction mechanism which is called Model Driven Engineering mechanism. In order to have a successful model based process, we need an appropriate tool such as version control systems to support our model-based process. On the other hand, developers need a mechanism to synchronize them with VCS systems. One of the concerns in modeling languages is the compatibility and the consistency of the models and modeling languages during their evaluation. the focus of the former researches was mostly on the consistency of the models during their evaluation, and to this end, lots of approaches have been proposed for keeping the consistency of the models... 

There has been great progress in Intelligent Transportation Systems (ITS) during the past decade. It is often difficult to manage vehicle traffic systems due to high variations and complexity. Intelligent Transportation Systems try to devise more efficient and more reliable solutions for vehicle traffic systems. Many ITS applications rely on short-term predictions of traffic state and it is crucial to provide reliable estimates of the traffic state in near future.Providing an accurate estimate of transportation time in a specific piece of street is a key task in Intelligent Traffic Systems (ITS). This estimate can be either for the moment or a future prediction. A practical ITS must be... 

Cancer is a complicated disease. So, cancer treatment can not be possible without understanding its complex behavior. Each of cells do inner operations spontaneously and have interactions on external environment. This feature of cells has caused to model their behaviors using multi-agents and considering each cell as an intelligent agent. Using this approach, a novel multi-scale agent-based model known as basic model has been introduced. Furthermore, two signaling pathways have been added to this model. For simulation, a new agent-based modeling framework has been proposed. After that, learning has been involved, for considering drug effects. Finally, by means of this model we can predict... 

The development of technologies and some defects in medicine caused to emerge a new approach called precision medicine. Unlike the traditional medicine, medical experts do best treatment for each patient based on his genetic characteristics in this approach. Predicting drug response on cancer cell lines is one of the most vital challenges in this area. Various approaches have been proposed to construct predicting models while the substantial distinctions between resistant and sensitive cell lines had been neglected in them. Here, we propose a new approach for constructing the predictive model. In our approach, we utilized the distinctions between sensitive and resistant cell lines and also... 

Proposing a comprehensive architecture for cloud federation with the aim of satisfying stakeholders the most, is one of the most challenging issues in this context. For an architecture to be comprehensive, requirements should be elicited thoroughly in early stages of architecture design. Since covering all requirements is a very complicated task, prioritization is considered to be a vital step which can help architects to focus on more important requirements in their design as well as to evaluate existing architectures. In this research, architecturally signifcant quality requirements of cloud federation for aggregated cloud architectures are studied and categorized. Moreover, elicited... 

Today, with the development of information systems and the use of information technology in organizations and the act of IT department to become out of isolation mode and also alignment of IT with the strategies and goals of the business units, many believe that the information should flow in organization without any borders. In addition to having common points, each of these frameworks have different features that make organizations have difficulties in choosing between them. It should be noted that the implementation of two or more frameworks together, can waste time and money, cause lots of rework, and also can lead conflicting outcomes in their organizations. Enterprise architecture... 

With the growing use of computer systems, especially in form of web applications, software development and customer requirements has become more complex. Modern computer systems are supposed to achieve non-functional requirements in addition to functional requirements. Non-functional requirements are also called software quality attributes. One of the most important quality attributes for today's software systems is performance. Today’s softwares due to the growing number of their users, need more efficiency than ever to properly meet the performance request.Storage components and databases are the most important factors in causing performance bottlenecks in web applications. Most of... 

Modeling is a tool to indicate mathematical structure of data and their relations.Game theory modeling defines utility functions by rationality property of agents. In game theory each agent attempt to maximize his(her) utility function.Game theory modeling is generally define under multi-agent systems in which each player is an autonomous agent in the multi-agent system. If we consider the whole system as a single agent that has one particular goal, accomplishment of this goal could be mathematically modeled. Objective function is the measure index to show how a system achieves its goal.Utility function in game theory and objective function can be conceptually correlated with each other in... 

The purpose of IT management and governance is to empower the alignment between IT and business in organizations. IT management and governance focuses on the optimal utilization of IT resources in order to support business processes, address the organization’s needs and meet the organization’s goals. Even though every IT governance framework emphasizes on a particular dimension of this extensive domain, the common nature of all these frameworks, which is IT and business alignment, would make the efforts put into integrating them desirable and reasonable. Implementing different IT governance frameworks in separate projects, not only results in redundant or inconsistent outputs and artifacts,... 

Controlling dynamical systems is an important area of research, having many applications in related practical fields. One class of dynamical systems which have obtained ever-growing importance in recent years are networked dynamical systems, in which dynamic behavior is observed on nodes interacting in a networked setting. This is mainly due to the rise of complex networks, e.g. social networks, as an important and powerful method of capturing dynamic behavior that exists in different systems. One important aspect of such systems is that in many scenarios, actors that participate in them are selfish and act rationally based on their own self interest. Therefore guiding such systems to...