Sharif Digital Repository

Microgrids will be key components of future smart grids that integrate distributed generation energy with local loads and units for greater efficiency. However, the uncertainty and intermittent nature of renewable energy products prevent the reliable operation of the micro-grids. On the other hand, the introduction of electric vehicles into the transportation industry can be both a challenge and an opportunity for the power grid. Using electric vehicle batteries as an energy storage system is a new work in the smart grid environment. Using an electric vehicle battery as a storage system makes it possible to create a grid with a lower operating cost because of the development of renewable... 

Today, Research and Development (R&D) plays an underlying role in all technology-based companies. It is the R&D that creates competitive advantage and determines survival or growth of a company in the fierce market place. R&D, On the other hand, consumes invaluable resources such as capital, human resource, and laboratories which are generally very scarce. This implies that R&D decisions must be treated as huge investment decisions which are made within the strategic framework of a business. The purpose of R&D portfolio selection is to select a set of projects from a pool of candidate projects in order to maximize some financial measures subject to resource availability and technical... 

English language is peppered with phrasal verbs (PhVs) and native speakers use them frequently and endlessly in daily life. However, due to various semantic and syntactic difficulties, polysemy, unpredictability, and learners’ L1 differences, this omnipresent aspect of English language morphology poses formidable challenges for learners in terms of fluency and accuracy, and leads them to resort to avoidance strategies. The problem has also been exacerbated with the arbitrariness of PhVs’ teaching methods prescribed by various textbooks. In order to shed more light on the ongoing debate over implicit and explicit types of instruction as two viable approaches to tackling PhVs, this study aimed... 

In this thesis, we apply robust optimization to analyze the uncertainty of model parameters of a portfolio optimization which contains stock options. We also develop two robust counterpart models for single period and multiperiod problems. By assuming that the probability distribution of parameters is not known, their uncertainty is considered to lie within known linear intervals. Due to the existence of nonlinear relations (piecewise linear) between uncertain data (stock and option price), we present an over-conservative robust model to make the solution feasible for all parameters. However in the second model by adopting a different approach we develop a robust counterpart model with... 

English research articles (henceforth RAs) have evolved into a vital medium for conveying and disseminating scientific knowledge. Mastering textual and linguistic conventions of academic prose assists English native and non-native authors in writing scientific RAs. Lexical bundles (LBs) refer to word combinations that co-occur frequently in a particular register (Biber, Johansson, Leech, Conrad & Finegan, 1999). In fact, they are an integral component of “fluent linguistic production” (Hyland, 2018, p. 4). For more than a century, LBs have attracted researchers' attention in corpus-driven studies, although the extent to which LBs vary between English native and non-native authors remains... 

In this study some experiments were performed to investigate the effect of sweep angle on the transition location of laminar flow to turbulent flow. Three half wing models were used, each having a different sweep angle but with the same aspect ratio in various angles of attack. Two flat plates were used at the ends of the swept wing models to prevent the flow from rolling up over the wing. By simulating flow over infinity swept wing by eliminating tip vertices, the effect of sweep angle on flow transition phenomenon was investigated.
The experiments included the study of transition flow via hot-film sensors, which were glued on the wing surface. We found that the small leading-edge... 

For many reasons the Montecarlo method is chosen for investigation of problems like shielding. Nowadays, superiority of utilizing the codes based upon Montecarlo methods such as using cross sections with continuous energy or using exact models of complex geometries, is obvious for everyone. But obtaining results with least possible variance is extremely important. variance reduction methods usedfor achieving exact results with less calculating time. Up to now in the MCNP codes, many methods have been utilized for reducing the variance. One of the methods which have recently attracted attentions is using the importance function. For obtaining importance function we need to solve the... 

One of the most vital aspects of understanding the traffic phenomenon is scrutinizing the traffic transition status, such as the transition from free flow to congestion. The Percolation Theory is a renowned theory focusing on analyzing various network types to detect the critical zones, which are the zones including links that are important to control to improve stability. By calculating the quality indices of network links, the Percolation Theory can simulate the traffic percolation propagation in the network and determine possible critical zones for further analysis. Most studies in this field assume access to data of several traffic parameters for the entire transportation network, such... 

Photodynamic therapy that has developed over last century, now has become more widely used medical tool for the treatment of various diseases such as cancer. This technique involves delivery of photosensitizing drugs, irradiation of light and motivation of drugs. The limitation of light penetration in body tissue, may resolve by application of upconversion nanoparticles. Upconverting nanoparticles could help treatment of cancer tumors in deep or critical points of body by converting high penetrating Near-Infrared emissions to higher energy visible emissions.In this research Er3+-Yb3+ Co-doped titanium dioxide upconversion nanoparticles prepared by Sol-gel method. The phase structure and...