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EXAF: A search engine for sample applications of object-oriented framework-provided concepts
, Article Information and Software Technology ; Volume 75 , 2016 , Pages 135-147 ; 09505849 (ISSN) ; Heydarnoori, A ; Sharif University of Technology
Elsevier
2016
Abstract
Object-oriented application frameworks, such as Java Swing, provide reusable code and design for implementing domain-specific concepts, such as Context Menu, in software applications. Hence, use of such frameworks not only can decrease the time and the cost of developing new software applications, but also can increase their maintainability. However, the main problems of using object-oriented application frameworks are their large and complex APIs, and often incomplete user manuals. To mitigate these problems, developers often try to learn how to implement their desired concepts from available sample applications. Nonetheless, this introduces another hard and time-consuming challenge which...
Classification of Motor Imagery in Electroencephalogram Signal Based on Spatio-temporal Feature selection Using Elastic Net
, M.Sc. Thesis Sharif University of Technology ; Jahed, Mehran (Supervisor)
Abstract
Motor imagery causes Event related Synchronization/Desynchronization (ERS/ERD) in Electroencephalogram (EEG) signal. These potentials can be used as an input for a Brain Computer Interface (BCI) system. To do so, it is necessary for these inputs to be correctly classified. The quality of classification is severely affected by the features extracted. Common Spatial Patterns (CSP) algorithm is often used for this task. Some of this method disadvantages are neglecting non-stationary properties of EEG signal and its proneness to overfitting. Additionally, its success is highly dependent on the frequency band that the algorithm is performed in. The most suitable sub band is interchangeable...
Design and Implementation of a Search Engine for Sample Applications of Object-Oriented Framework-Provided Concepts
, M.Sc. Thesis Sharif University of Technology ; Heydarnoori, Abbas (Supervisor)
Abstract
An object-oriented application framework, like Eclipse, not only provides a framework for designing and implementing new applications, but also decreases the time and the cost of developing new software applications. Moreover, theseframeworks increase the maintainability of software systems. Therefore, their popularity is on the rise. The main problem of using object-oriented application frameworks is the lack of proper documentations and guides. Thus, developers often try to learn how to implement their desired concepts (e.g., Context Menu) from available sample applications. This leads the programmers to another problem which is finding the sample applications. Finding a proper sample...
Synthesis and characterization of bagasse poly(methyl methacrylate) graft copolymer
, Article Macromolecular Symposia ; Volume 274, Issue 1 , 2008 , Pages 49-54 ; 10221360 (ISSN) ; Pourjavadi, A ; Noei Aghaei, M. A ; Sharif University of Technology
2008
Abstract
Graft copolymerization of methyl methacrylate (MMA) was carried out on bagasse fibers in an aqueous medium using eerie ammonium nitrate (CAN) as initiator under a neutral atmosphere. In order to obtain the optimum condition for graft copolymerization, the effects of initiator concentration, temperature, time of reaction, and monomer concentration were studied. The maximum grafting percent was found to be 122%. The bagasse grafted poly(methyl methacrylate) was characterized by FTIR and its thermal behavior was characterized by TGA. Copyright © 2008 WILEY-VCH Verlag GmbH & Co. KGaA
Classification of EEG signals using the spatio-temporal feature selection via the elastic net
, Article 2016 23rd Iranian Conference on Biomedical Engineering and 2016 1st International Iranian Conference on Biomedical Engineering, ICBME 2016, 23 November 2016 through 25 November 2016 ; 2017 , Pages 232-236 ; 9781509034529 (ISBN) ; Ashtari, P ; Jahed, M ; Vahdat, B. V ; Sharif University of Technology
2017
Abstract
Effective classification of motor imagery electroencephalograph (EEG) data is an important challenge. Spatial filtering such as Common Spatial Pattern (CSP) and its variants are commonly used for this task. However, CSP effectiveness depends on the subject-specific frequency band. Even by optimally selecting a subject-specific frequency band, this method still fails for some subjects. On the other hand, some studies suggest that temporal features may discriminate classes more efficiently. This work proposes a hybrid method based on elastic net and Least Absolute Shrinkage and Selector Operator (LASSO) to optimally select between spatial and temporal features. This algorithm uses joint...
Using Automata-based techniques for Energy Management in Embedded Systems
, M.Sc. Thesis Sharif University of Technology ; Ejlali, Ali Reza (Supervisor)
Abstract
These days, societies prefer to use systemsthat provide more utilities with rapid processing. This lead to make large volume of information to process.And also, the number of processors used in embedded systems is more than the number of them in PC. Gradually, the embedded systems own complex processor. On the other hand, according to the Moore’s law, the number of transistors on a chip doubles every eighteen months. That lead to be more complex. And also, based on predictions, the amount of software used in most of electronic devices doubles every two years.The increasing of amount of information and high-performance expecting havecaused increaseprocessing. The increasing requires more...
Energy analysis of part flow and full flow Humid Air Turbine Cycle (HAT)
, Article 2006 ASME 51st Turbo Expo, Barcelona, 6 May 2006 through 11 May 2006 ; Volume 4 , 2006 , Pages 319-327 ; 0791842398 (ISBN); 9780791842393 (ISBN) ; Khaledi, H ; Bakhtiari, B ; Ghofrani, M. B ; Sharif University of Technology
2006
Abstract
Current researches on the development of gas turbine related power plants such as HAT cycle and Combined Cycle are aimed to increase the plant efficiency and output power, while reducing the cost of power generation and emission. Humid air turbine cycle (HAT) is one of innovative cycles, which are able to provide a substantial power boost of the system and an efficiency rise of several percentage points. In order to perform energy analysis of Full Flow HAT cycle and Part Flow HAT cycle an advanced thermodynamic model is developed, which is enabling evaluation of behavior of Full Flow and Part Flow Humid Air Turbines and predicting the influence of operational parameters in the performance of...
On the graphs with minimum sombor Index
, Article Match ; Volume 88, Issue 3 , 2022 , Pages 553-559 ; 03406253 (ISSN) ; Akbari, S ; Madadinia, S ; Noei, M ; Salehi, F ; Sharif University of Technology
University of Kragujevac, Faculty of Science
2022
Abstract
For a graph G the Sombor index of G is defined as (Formula Presented) , where d(u) is the degree of u in G. In the current paper, we study the structure of a graph with minimum Sombor index among all graphs with fixed order and fixed size. It is shown that in every graph with minimum Sombor index the difference between minimum and maximum degrees is at most 1. © 2022 University of Kragujevac, Faculty of Science. All rights reserved
Genco's Bidding Strategy in Day-Ahead Energy Market Considering Demand Response
, M.Sc. Thesis Sharif University of Technology ; Ehsan, Mehdi (Supervisor)
Abstract
Since 1980s the electricity market has been gradually evolving from a monopoly market into a liberalized one for encouraging competition and improving efficiency. This brings the opportunity for generation companies (Gencos) to make more profits while embracing more risks of not being dispatched. Therefore, it has become a core interest for the Gencos to develop optimal bidding strategies to maximize the profits and minimize the risks while participating in such a competitive market. Error of determining day-ahead electricity price is one of the sources of the risk. Energy price has a high impact on bidding strategy optimization process. So it should be determined with low error which is not...
Multi Objective Distributed Generation Planning in a Flexible Environment
, Ph.D. Dissertation Sharif University of Technology ; Ehsan, Mehdi (Supervisor)
Abstract
The process of deregulation that has involved electricity many markets has introduced several new interesting research topics in power system area. This thesis addresses one of the most fascinating issues among them: the study of distributed generation both renewable and conventional integration in distribution networks. From the distribution network operator (DNO)'s point of view, it is of interest to develop a comprehensive methodology which considers various distributed generation technologies as an option for supplying the demand in distribution networks. In this thesis, the planning problem has been multi-objectively modeled. This will help the planner in decision making while knowing...
, M.Sc. Thesis Sharif University of Technology ; Ehsan, Mehdi (Supervisor)
Abstract
Losses are unavoidable in any parts of power systems, from generation to receiving nodes and occur in transmission and distribution networks. However, the main loss component is produced in distribution networks. Energy losses in distribution networks are about 70% of technological transport energy losses.
Energy losses in distribution networks are an important indicator for the planning and operation of the system. A fast, reliable and accurate energy loss calculation method is required for optimal operation of the distribution networks.
Energy loss depends on network's operating conditions. Loads values and loads factors are time variables; therefore, methods based on probability...
Energy losses in distribution networks are an important indicator for the planning and operation of the system. A fast, reliable and accurate energy loss calculation method is required for optimal operation of the distribution networks.
Energy loss depends on network's operating conditions. Loads values and loads factors are time variables; therefore, methods based on probability...
Methods of Clearing Reactive Power Market and Cost Allocation in Pool Structure
, M.Sc. Thesis Sharif University of Technology ; Ehsan, Mehdi (Supervisor)
Abstract
Restructuring and privatization in power system such as any industry leads to better market operation and more social welfare. Since two decade the power system in many countries have changed from monopoly to free market. In a restructured network the technical and economical aspects should be considered together. Ancillary services are needed for any power system to be operated in an optimal and secure manner. Reactive power and voltage regulation is one of the most important ancillary services in the network. this service should be supplied by its providers through a competitive market and system operator determines the optimal dispatch among different bids. The cost of purchasing reactive...
Dynamic Security Assessment in Restructured Power Systems
, Ph.D. Dissertation Sharif University of Technology ; Ehsan, Mahdi (Supervisor)
Abstract
This thesis addresses the problem of dynamic security assessment in power sys-tems with an emphasis on its application in restructured power systems and issues arising in its applications. The new electric utility environment has an immedi-ate consequence of emphasis on reliability and secure operation of power systems. This requires faster and more precise methods to assess the dynamic aspect of se-curity. On the other hand, this issue is becoming challenging when the determined dispatch might not be accommodated due to violation of the limits.This thesis addresses the problem of dynamic security assessment in power sys-tems with an emphasis on its application in restructured power systems...
Optimal Sizing and Operation of CHP Based on Stochastic Programming
, M.Sc. Thesis Sharif University of Technology ; Ehsan, Mehdi (Supervisor)
Abstract
CHP (Combined Heat and Power) generates electricity and thermal energy simultaneously from input fuel. Since it has high energy efficiency and low installation time, it is an appropriate approach in energy management of residential complexes. In this project, stochastic programming based on Monte Carlo approach is used to handle uncertainties in the optimal sizing of CHP for residential complexes. Availability of CHP, boiler and AC bus as well as the electrical and thermal load forecast errors are considered as stochastic variables. Minimizing system total cost considering the probability of each scenario obtained from the scenario reduction algorithm is the objective function. The system...
Planning of Energy Storage Systems with the Main Goal of Managing the Output Power of Wind Farms
, M.Sc. Thesis Sharif University of Technology ; Ehsan , Mehdi (Supervisor)
Abstract
Uncertain fuel prices and also global climate changes are accompanied by some state initiatives such as renewable portfolio standards (RPS). This has caused a fast growth in the amount of renewable energy installed worldwide especially wind energy over last decades. However, the intrinsic characteristics of wind farms output power, i.e. intermittency and volatility of wind speed along with being non-dispatchable in output generation of wind turbine raises many new technical and financial challenges for power system operators and planners. Up to these issues, large level of wind power penetration causes a growing concern in wind energy curtailment issue which the wind farm’s operator may be...
Retailer’s Medium-term Planning in Distribution Network Considering Uncertainty and Competitive Enviroment
, Ph.D. Dissertation Sharif University of Technology ; Ehsan , Mehdi (Supervisor)
Abstract
Electricity retailers are one of the power market entities which act as an intermediary between the producers in the wholesale market and the consumers in the retail side. The main task of a retailer in the power market is to set contract with the consumers to supply their electricity during a pre-specified time period and to participate in the wholesale market to supply the electricity needed by its costomers. Retailer’s contract with its customers may be a simple contract with a fixed pre-determined energy price or include some more complicated feathures such as involvement of a percent of green energy or variable price and demand response contracts. Moreover, retailer can supply its...
Scheduling of Retailers Performance in Electrical Energy Markets with Energy Production;Sell in Pool Market; and Demand Response Policies
, M.Sc. Thesis Sharif University of Technology ; Ehsan, Mehdy (Supervisor)
Abstract
Recent years of capitalism bold role and the competitive environment of variant fields of our life, sparking the idea which considers the electricity (one of the most crucial human requirement) as a commodity of a competitive market to be traded between confident subscribers by easy access. Therefore, by converting the exclusive structure of electricity supply system to a competitive one, some new roles are created to fulfill the electricity generation, transmission and distribution processes. Retail is one of the new roles, defined as a power system restructuring development helper by support of electricity trading, which can be involved in different transactions according to the market...
Linked Planning of Power Grids and Subsidy Policies on Using Photovoltaic Cells for Residential Electricity Supply
, M.Sc. Thesis Sharif University of Technology ; Ehsan, Mehdi (Supervisor)
Abstract
In recent years, due to restructuring in the electric power industry, distributed generation has become one of the most important subjects and DGs and renewable energy sources have been increasingly expected as a supplement and an alternative to a conventional large scale central power system. their success depends not only on the distribution of the available renewable energy sources in a region but also on the power grids connectable capacity in the area. Photovoltaic system is one of the best RESs for residential electricity supply because it is noiseless and solar power is widely available and households can use it via photovoltaic cells in their homes. There are two major problems...
Bidding and Offering Strategy of Hybrid Electric Companies in Day-ahead Energy Market
, Ph.D. Dissertation Sharif University of Technology ; Ehsan, Mehdi (Supervisor)
Abstract
This Thesis presents a new approach for determining the day-ahead bidding strategies of a hybrid electric energy company. The company has both energy generation and energy retailing businesses in a competitive electricity market. Demand response programs are also considered in the retail side of the company in order to hedge the risk of participation in wholesale market. Price-taker and price maker companies are considered in this thesis separateky.For the price-taker hybrid structure, the predivtion of day-ahead prices are used to evaluate the optimum bidding and offering strategies. Also, day-ahead market price uncertainty is modeled, using non-probabilistic Information Gap Decision Theory...
Security Constrained Unit Commitment With Natural Gas Transmission Delivery Constraints
, M.Sc. Thesis Sharif University of Technology ; Ehsan, Mahdi (Supervisor)
Abstract
Natural gas power plant installed in power system as rapid start unit. In the recent decades, with increasing in the number of gas generating units in the world, consideration of natural gas transmission network in optimal solution of security-constrained unit commitment (SCUC) become a non-negligible problem. The gas transmission grid constraints integrated into the scheduling of thermal units in the proposed model for minimizes power system operating cost. In a power plant transmission of natural gas to power plant is very important because congestion in natural gas pipeline increases. This model could consider natural gas storage tank in gas transmission network as decision variable....