Sharif Digital Repository

In this article, a universal collaborative and competitive approach is introduced for deployment of digital collections in an ideal Digital Library for future's educational system. A hierarchical structure is proposed to be used for browsing and searching within mass of digital contents provided for union of curriculums worldwide. The collaborative and open-source aspects of the system guarantee the growth of the Digital Library. On the other hand, the competitive and reviewing aspects guarantee the accuracy of the novel library contents. Two experiments confirm the need for such a universal Digital Library worldwide to enhance learning capabilities, increase accessibility, avoid redundancy... 

Reusing the programs which have already been developed can shorten the production time and reduce costs and expenses. One of the important issues in software reuse is finding a program or a program component in a program library which has been already developed and using it in the new program. In view of precision and automation that formal methods can provide, we can use formal methods in retrieval appropriate components from the software libraries. In this paper, some of the works done in the field of retrieval of the components from the libraries by the help of formal methods have been surveyed and reviewed  

Nowadays, we live in a Big Data world and many sectors of our economy are guided by data-driven decision processes. Big Data and Business Intelligence applications are facilitated by the MapReduce programming model, while, at infrastructural layer, cloud computing provides flexible and cost-effective solutions to provide on-demand large clusters. Capacity allocation in such systems, meant as the problem of providing computational power to support concurrent MapReduce applications in a cost-effective fashion, represents a challenge of paramount importance. In this paper we lay the foundation for a solution implementing admission control and capacity allocation for MapReduce jobs with a priori... 

There are several types of drilling methods to increase the productivity of a well, such as horizontal drilling, extended reach horizontal drilling and Multilateral (ML) drilling. It is thought that ML wells could be more economic with higher productivities than horizontal or extended reach horizontal wells. Advances in ML drilling promise reduced costs, greater flexibility and increased profit potential. In the last 20 years, thousands of ML wells have been drilled worldwide, but only a small percentage of the total number of wells is multilateral. The probable reason may be lack of concise information and misconceptions surrounding the costs and perceived risks. However, recent advances in... 

Sensorless control of permanent magnet synchronous motors allows reducing cost and complexity, and increasing mechanical robustness and noise immunity. Sensorless methods based on high frequency carrier injection have attracted considerable attention in recent years as they can estimate rotor position in a wide speed range. These methods employ anisotropic properties of rotor to estimate rotor position in ac machines. With internal permanent magnet motors, the high frequency signal injection method can deliver precise sensorless control, however in surface-mounted permanent magnet machines, where a small saliency arises from main flux saturation, the estimation of rotor magnet position is...