Loading...
Search for:
optimization-problems
0.008 seconds
Total 292 records
Fuzzy based generation scheduling of power system with large scale wind farms
, Article 2009 IEEE Bucharest PowerTech: Innovative Ideas Toward the Electrical Grid of the Future ; 2009 ; 9781424422357 (ISBN) ; Vakilian, M ; Sharif University of Technology
Abstract
Wind power introduces a new challenge to system operators. Unlike conventional power generation sources, wind power generators supply intermittent power because of uncertainty in its resource. In a power system involved largescale wind power generation scenario, wind intermittency could oblige the system operator to allocate a greater reserve power, in order to compensate the possible mismatch between predicted and the actual wind power output. This would increase the total operation cost. This paper presents a new approach in fuzzy based generation scheduling (GS) problem using mixed integer nonlinear programming (MINLP). While the reserve requirements, load generation balance and wind...
Optimal design of two-dimensional porosity distribution in shear deformable functionally graded porous beams for stability analysis
, Article Thin-Walled Structures ; Volume 120 , 2017 , Pages 81-90 ; 02638231 (ISSN) ; Arghavani, J ; Sharif University of Technology
Abstract
In the present study, considering two-dimensional porosity distribution through a functionally graded porous (FGP) beam, its optimal distributions are obtained. A multi-objective optimization problem is defined to maximize critical buckling load and minimize mass of the beam, simultaneously. To this end, Timoshenko beam theory is employed and equilibrium equations for two-dimensional functionally graded porous (2D-FGP) beam are derived. For the solution, we present generalized differential quadrature method (GDQM) and consider two symmetric boundary conditions (Clamped-Clamped and Hinged-Hinged). Solving generalized eigenvalue problem, critical buckling load for 2D-FGP beam is then obtained....
A probabilistic energy management scheme for renewable-based residential energy hubs
, Article IEEE Transactions on Smart Grid ; Volume 8, Issue 5 , 2017 , Pages 2217-2227 ; 19493053 (ISSN) ; Fotuhi Firuzabad, M ; Zareipour, H ; Moeini Aghtaieh, M ; Sharif University of Technology
Abstract
This paper proposes a new framework for home energy management (HEM) in the context of renewable-based residential energy hub using a probabilistic optimization approach. Different energy converters and storages, including combined heat and power, a plug-in hybrid electric vehicle, a heat storage unit, solar panels, and generic household appliances, are considered in the energy hub. The customer's energy cost is considered as the objective of the HEM optimization problem and different operational limits of the energy hub components are modeled as the constraints. The two-point estimate method is incorporated in this paper to model the uncertainty associated with output power of the rooftop...
Opposition-based learning for competitive hub location: a bi-objective biogeography-based optimization algorithm
, Article Knowledge-Based Systems ; Volume 128 , 2017 , Pages 1-19 ; 09507051 (ISSN) ; Akhavan Niaki, S. T ; Akhavan Niaki, S. A ; Sharif University of Technology
Abstract
This paper introduces a new hub-and-center transportation network problem for a new company competing against an operating company. The new company intends to locate p hubs and assign the center nodes to the located hubs in order to form origin–destination pairs. It desires not only to maximize the total captured flow in the market but also aims to minimize the total transportation cost. Three competition rules are established between the companies which must be abided. According to the competition rules, the new company can capture the full percentage of the traffic in each origin-destination pair if its transportation cost for each route is significantly less than of the competitor. If its...
Online hybrid model predictive controller design for cruise control of automobiles
, Article ASME 2017 Dynamic Systems and Control Conference, DSCC 2017, 11 October 2017 through 13 October 2017 ; Volume 1 , 2017 ; 9780791858271 (ISBN) ; Abbaszadeh Chekan, J ; Salarieh, H ; Alasty, A ; Sharif University of Technology
Abstract
In the proposed study, a Hybrid Model Predictive Controller is introduced for cruise control of an automobile model. The presented model consists of the engine, the gearbox, and the transmission dynamics, where the aerodynamics force and elastic friction between the tires and road are taken into account. Through Piecewise Linearization of nonlinearities in the system; (torque)-(throttle)-(angular velocity) of engine and (aerodynamic drag force)-(automobile velocity), a comprehensive piecewise linear model for the system is obtained. Then combined with the switch and shift between engaged gears in gearbox, the Piecewise Affine (PWA) model for the vehicle dynamics is acquired. As far as the...
Efficient convex solution for 3-D localization in MIMO radars using delay and angle measurements
, Article IEEE Communications Letters ; Volume 23, Issue 12 , 2019 , Pages 2219-2223 ; 10897798 (ISSN) ; Amiri, R ; Behnia, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this letter, an efficient estimator for 3-D target localization in distributed multiple-input multiple-output (MIMO) radars using time delay (TD) and angle of arrival (AOA) measurements is proposed. First, an approximately equivalent maximum likelihood (ML) estimation problem is formulated. Then, the aforementioned ML problem is recast into a convex optimization problem for which we derive a semi closed-form solution that eventually boils down to finding the roots of certain polynomials. Using numerical simulations, we demonstrate that the proposed estimator reaches the Cramer-Rao lower bound (CRLB) up to relatively high Gaussian measurement noise levels. Furthermore, the proposed method...
Spatio-temporal VLAD encoding of visual events using temporal ordering of the mid-level deep semantics
, Article IEEE Transactions on Multimedia ; Volume 22, Issue 7 , 2020 , Pages 1769-1784 ; Amini, S ; Ghaemmaghami, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
Classification of video events based on frame-level descriptors is a common approach to video recognition. In the meanwhile, proper encoding of the frame-level descriptors is vital to the whole event classification procedure. While there are some pretty efficient video descriptor encoding methods, temporal ordering of the descriptors is often ignored in these encoding algorithms. In this paper, we show that by taking into account the temporal inter-frame dependencies and tracking the chronological order of video sub-events, accuracy of event recognition is further improved. First, the frame-level descriptors are extracted using convolutional neural networks (CNNs) pre-trained on ImageNet,...
A novel low-complexity dynamic frequency selection algorithm for cognitive radios
, Article 4th IEEE International Symposium on Wireless Communication Systems 2007, ISWCS'07, Trondheim, 16 October 2007 through 19 October 2007 ; 2007 , Pages 558-562 ; 1424409799 (ISBN); 9781424409792 (ISBN) ; Khalaj, B. H ; Sharif University of Technology
2007
Abstract
In this paper, a non-cooperative distributed frequency selection algorithm is proposed for cognitive radio networks in which in addition to interference minimization, the minimization of implementation complexity and probability of interruption of secondary users are also addressed. The convergence and interference reduction property of the algorithm is also demonstrated using game theoretic concepts. In order to evaluate the performance of the algorithm, the associated optimization problem is formulated into a variant of graph colouring problem, and a centralized algorithm is also proposed as an approximation of the optimal solution. Finally, simulation results demonstrate that the proposed...
Optimal reactive power dispatch in electricity markets using a multiagent-based differential evolution algorithm
, Article International Conference on Power Engineering, Energy and Electrical Drives, POWERENG 2007, Setubal, 12 April 2007 through 14 April 2007 ; 2007 , Pages 249-254 ; Tabatabaii, I ; Hosseini, S. H ; Sharif University of Technology
2007
Abstract
Reactive power dispatch in power systems is a complex combinatorial optimization problem involving nonlinear functions with multiple local minima and nonlinear constraints. In an open electricity market reactive power support is an ancillary service for real power transportation. From the viewpoint of ISO, this paper provides a dispatching reactive power model, based on optimal power flow, by which both the cost of procuring reactive power as auxiliary service and the losses of active power are minimized. In this paper the cost of reactive power support consists of two components: reactive power cost of generators and shunt capacitors. In addition an extremely powerful differential evolution...
Development of a framework for the sustainability evaluation of renewable and fossil fuel power plants using integrated LCA-emergy analysis: A case study in Iran
, Article Renewable Energy ; Volume 179 , 2021 , Pages 1548-1564 ; 09601481 (ISSN) ; Avami, A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
This study presents a comprehensive framework for evaluating renewable and non-renewable power plants' performance using the Life Cycle Analysis (LCA) and emergy analysis. The emergy analysis is used to consider the free ecosystem services in the sustainability of the systems as a supplement to the LCA. The results indicate that the wind and photovoltaic power plants have the best performance in terms of the LCA analysis, while the wind and combined cycle power plants have the highest emergy sustainability index. The best scenario is chosen under a two-objective optimization problem, including the single score and emergy sustainability as objective functions. Here, the wind power plant is...
Development of a framework for the sustainability evaluation of renewable and fossil fuel power plants using integrated LCA-emergy analysis: a case study in Iran
, Article Renewable Energy ; Volume 179 , 2021 , Pages 1548-1564 ; 09601481 (ISSN) ; Avami, A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
This study presents a comprehensive framework for evaluating renewable and non-renewable power plants' performance using the Life Cycle Analysis (LCA) and emergy analysis. The emergy analysis is used to consider the free ecosystem services in the sustainability of the systems as a supplement to the LCA. The results indicate that the wind and photovoltaic power plants have the best performance in terms of the LCA analysis, while the wind and combined cycle power plants have the highest emergy sustainability index. The best scenario is chosen under a two-objective optimization problem, including the single score and emergy sustainability as objective functions. Here, the wind power plant is...
Design Optimization of a Ladder Secondary Single-Sided Linear Induction Motor for Improved Performance
, Article IEEE Transactions on Energy Conversion ; Volume 30, Issue 4 , 2015 , Pages 1595-1603 ; 08858969 (ISSN) ; Nasiri Gheidari, Z ; Sharif University of Technology
Abstract
In this paper, design and optimization of a ladder-type single-sided linear induction motor (Ladder SLIM) for machine tool applications is investigated. High-speed linear induction machines suffer from the end-effect phenomenon, which can reduce the thrust and result in declined output characteristics. Although it is common to consider this phenomenon in high-speed applications, it is essential to take it into account in the design and analysis of low-speed low-air-gap linear machines. In addition, Ladder SLIMs have significant flux density ripples, and using skewed bars for secondary of the machine is a common solution for it. Therefore, providing required equations, an algorithm for...