Sharif Digital Repository

In a network of caches, the precious cache space must be efficiently managed. A wasteful cache management algorithm might make redundant copies of the same content at several caches. Therefore, there must be an algorithm (a.k.a admission policy) to find a proper location in the network for every content to be cached. One way to locate different content at different caches is based on content popularity. Thus, popular content is closer to requesters. However, measuring content popularity at every router is not practical due to the high overhead the algorithm imposes on the routers. A more practical approach is to distribute different parts of the content to several caches along the path from... 

The ability of blockchain to record transactions and automatic execution feature in smart contracts, increase the speed of the supply chain and reduce unnecessary delays. A blockchain-enabled supply chain is more dynamic and responds to changes faster. This makes many processes more efficient in the supply chain. Supplier performance evaluation is an essential field in Supply chain management. At any time, by recording real-time data through smart contracts in the blockchain, it is possible to see the supplier’s performance in different aspects according to all the information recorded up to that moment. This research investigates the use of smart contracts and blockchain in solving supply... 

Due to the numerous climate fluctuations and inefficient management of water resources during recent decades in Iran, the condition of some wetlands has become critical and the need for rehabilitation has increased. The importance of the wetlands and plains ecosystem have led to initiate some extensive projects to preserve and revive them. While implementing the projects some questions have been raised by the scientists and public whether the impact and success of these projects are in direct with objectives of the restoration program or not.For instance, Urmia Lake as one of the most precious natural habitats of Iran and as one of the biological reservoirs of the world is selected for this... 

The performance evaluation involves a process by which the employees are periodically and officially evaluated. Major reasons of performance evaluation include, among others, identification of efficient employees and granting bonuses to them to create stimuli to improve their and other employees' performances. The main objective of performance evaluation constitutes study of people's performances in the organization in order for directors to take proper and required decisions to enhance both quantities and qualities of the employees' works. The performance evaluation is deemed to be a major critical function of the management of human resources to facilitate organizational effectiveness. In... 

In this paper the predictive equations for collapse assessment of shear links used in eccentric braced frames are developed. An extensive database including results of over 70 cyclic tests on steel wide flange shear links is collected and the structural parameters governing the hysteresis behavior are calibrated using a simplified numerical model. The methodology of calibration is to minimize the discrepancy between the experimental hysteresis loops and the corresponding numerical results using Particle Swarm Optimization (PSO) algorithm. The objective function of PSO algorithm is minimized by iterating parameters that govern the hysteresis behavior of the numerical model. Stepwise... 

Businesses are dependent on mining of their Big Data more than ever and configuring clusters and frameworks to reach the best performance is still one of the challenges. An accurate performance prediction of the Big Data application helps reduce costs and SLA-violations with better tuning of the configuration parameters. Among the Big Data frameworks, Hadoop, Tez, and Apache Spark are the widely used and popular ones, with the MapReduce and graph-based workflows, usually running on top of the YARN cluster. While a great number of attempts have been made to predict the execution time of Big Data applications, to the best of our knowledge, none of them considered multiple simultaneous YARN... 

Long and continuous running of software is likely to cause software aging-induced errors and failures. Cloud service centers suffer from such errors because of degradation of virtual machine monitors (VMMs) that oversee the execution of virtual machines (VMs). The proposed solution to prevent such VMM failures is to use a rejuvenation scheme for planned termination and restarting of monitor software. The best measure to determine the optimum time of rejuvenation is the VMM’s age, that is, the cumulative workload carried out since the last reboot, repair, or rejuvenation. This paper provides an analytical model based on stochastic activity network (SAN) tool for performance evaluation of... 

Environmental conditions have a significant effect on the performance of flexible pavements. External factors such as precipitation, temperature, freeze-thaw cycles, and depth to water table play a key role in defining the extent of the impact the environment effects on pavement performance. All types of pavement distress are either caused or aggravated by the environmental factors. Up until now, pavement design in Iran is done according to the AASHTO 1993, which is based on methods that have evolved from the AASHTO Road Test that was conducted at one specific geographic location. The newly released Mechanistic Empirical Pavement Design Guide (MEPDG) by the addition of climatic input makes... 

Considering the multi-disciplinary aspects as well as the importance of a wide performance map of a propulsion system, this thesis is focused on the preliminary design aspects of an axial flow pump with an inlet guide vane. First, a one-dimensional design algorithm is developed. The code is used to perform a preliminary design of a prototype pump. The results are used to carry on a detailed 3D design by using commercial software. The obtained geometry and performance map are compared with available data. Finally, the finalized code is employed to design and analyze a one megawatt axial pump with and without inlet guide vanes  

The current thesis argues about employee Performance Appraisal System (PAS) of damavand project which is one of the MAPNA Combined Cycle Power Plant Construction and Development Co (MD-2) projects.A few studies have been done in the field of human resource management in project structure and project-based organizations in comparison with classic organizations structure. the PAS might have a different role in project structure as a function in human resource management.In this research the required data has collected via interview with employees and some top managers of MD-2 Company.and Theme analysis has been used to analyzing the data. this study has described the effect of organizational,... 

Electrical machines represent an important research area in electrical engineering with numerous industrial applications. Multiphase induction machines are considered as the new generation of electrical machines in industrial applications because of their structure, robustness, simplicity, reasonable cost, long lifetime, and high reliability. A solution in the way of improving induction machine performances is using concentrated windings because they have many advantages such as short non-overlapping end turns, high fault-tolerant capabilities, and easy manufacturing. The main drawback of concentrated windings is its low-quality air gap flux density which significantly deteriorates induction... 

In today’s business world, team working as one of the most useful solutions to improve organizational performance and efficiency is used by different organizations and companies. Many experts and academic researchers are focused on teams and team based organizations in their studies and tried to find its cause and effect on organizational performance in the past two decades. Also different variables are recommended as influencing factor on team performance by different authors, In spite of all these researches, no fixed list of these factors, which are been acceptable by reasonable number of researchers and experts, can be find yet. This study tries to present the results of an experimental... 

Several studies in the field of performance management have paid attention to the effect of systemic and instrumental factors on the effectiveness of performance management system. However, the impact of communication and relational factors has received less attention. Furthermore, it seems that similar approach has been used in organizations for considering systemic factors in designing performance management systems rather than human factors. The goal of this research was to study the relationship between employees' trust in their manager as an relational variable with the effectiveness of performance management system and to compare this relationship with the relationship between the... 

Since the start of Covid-19 pandemic lately in 2019 from Wuhan in China, a lot of countries encountered it. Healthcare sysytems are the most important system against pandemics so it is needed to measure the efficiency of healthcare systems against Covid-19 in order to find best practices. In this research, a 3-phased method is proposed to evaluate the performance of the healthcare systems. In the first phase, countries are clustered, in the second phase the DEA model is applied in 2 separate parts, in one part with considering clusters and in another without it. In the third phase resilience is introduced for Covid-19 and then it is used as a criterion beside two other criteria, DEA result... 

Decreasing cost, enhancing quality, increasing the customer satisfaction and the productivity to gain farther market shares are among the reasons for urging the companies to outsource their needs. In this study the definition of outsourcing, its advantages and weaknesses and the risks associated with it are presented and then models for decision making on outsourcing and its implementation process are discussed. As a scope for this mention, then the evaluation of outsourcing procedures for the paint shops is selected and studied. A model for the case is also presented. The case study is undertaken in Iran Khodro's paint shop during the years: 1379 – 1384 as a practical case. We can summarize... 

The Intelligent Transportation Systems (ITS) are aimed to provide innovative services to improve safety of the traffic and make the use of the transport networks more coordinated. Such services are implemented by establishing wireless communications among the vehicles. The resulting mobile ad hoc network formed among the moving vehicles is called the Vehicular Ad Hoc Network (VANET). The IEEE 802.11p has been emerged as the first standardized contention-based MAC protocol for VANETs. The overall performance of the contention-based MAC protocols is directly dependent on the number of the contending nodes . To analyze the performance of the 802.11p protocol, most of the existing approaches... 

Delay-tolerant networks refer to the networks that lack stable end-to-end paths due to the high mobility of nodes. In order to tackle the intermittent connections, nodes of delay-tolerant networks store the data packets and carry them. Nodes forward data packets according to routing protocols once they enter each other's communication range. In order to increase the probability of delivery, several or many copies of a packet can be disseminated in the network. Over the past years, various routing protocols have been proposed for delay-tolerant networks. These protocols differ from each other in the number of copies that are disseminated in the network or the information used to make routing... 

Caching has been widely considered an efficient way of reducing and balancing the growing traffic in communications networks in recent years. In this thesis, for the first time, the stochastic requests traffic model in communication networks is considered and a performance analysis is provided based on such a realistic assumption. In addition, we introduce new comprehensive performance metrics which simultaneously take into account, the cache hit probability, load on the bottleneck links, and requests arrival rates. The main contribution of this thesis is to present a system model based on queuing theory and provide an analysis of the stability, maximum stable throughput, load on the... 

With the expansion of knowledge-based economics literature in the last two decades in the country, the analysis and evaluation of the performance of policies applied in this field, especially the concept of innovation and technology ecosystems, is of particular importance. One of the leading branches in this field is the Sharif Innovation District, which is centered on Sharif University of Technology and has always been a important platform for implementing innovative policies in the country. In this research, we analyzed the development of Sharif innovation district. This research is a qualitative research with thematic analysis research method and inductive approach. To carry out the... 

In this paper, we propose a run-time strategy for managing writes onto last level cache in chip multiprocessors where STT-RAM memory is used as baseline technology. To this end, we assume that each cache set is decomposed into limited SRAM lines and large number of STT-RAM lines. SRAM lines are target of frequently-written data and rarely-written or read-only ones are pushed into STT-RAM. As a novel contribution, a low-overhead, fully-hardware technique is utilized to detect write-intensive data blocks of working set and place them into SRAM lines while the remaining data blocks are candidates to be remapped onto STT-RAM blocks during system operation. Therefore, the achieved cache...