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objective-functions
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Optimal Placement of Active Filters in a Power System
, M.Sc. Thesis Sharif University of Technology ; Mokhtari, Hossein (Supervisor)
Abstract
The extensive use of nonlinear loads such as motor drives and new generation of home appliances has caused a deterioration of power quality in power systems. The use of active power filters due to the fast variation of the loads has been recommended by power engineering. In this method, the harmonic profiles are controlled by applying active filters in a distribution feeder. Optimal placement of active filters in a distribution system due to the increase of harmonic generation loads has attracted researchers. However placement of each filter is the major concern that researchers face. In this paper, a new objective function is introduced to determine the optimal number and location of active...
REFER: A reliable and energy-efficient RPL for mobile IoT applications
, Article 3rd CSI/CPSSI International Symposium on Real-Time and Embedded Systems and Technologies, RTEST 2020, 10 June 2020 through 11 June 2020 ; July , 2020 ; Salehi, A. A. M ; Taghizadeh, H ; Safaei, B ; Hosseini Monazzah, A. M ; Ejlali, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
Recently, IoT has been massively applied in different areas of human life. Meanwhile, in many of the IoT applications, e.g., the remote patient health-care monitoring systems, the reliability of communications, and the consumed energy in IoT devices, which are mostly battery-operated, are very challenging. Since IoT devices are typically operated in lossy environments, providing a reliable transmission for the packets imposes a noticeable amount of energy consumption. In addition, the runtime movement of the IoT devices in mobile networks further intensifies these issues. Therefore, the applied policies in the IPv6 RPL as the standard routing mechanism in IoT networks, play an important role...
Optimal placement of fast charging station in a typical microgrid in Iran
, Article International Conference on the European Energy Market, EEM ; 2013 ; 21654077 (ISSN); 9781479920082 (ISBN) ; Kashanizadeh, B ; Vakilian, M ; Barband, S. A ; Sharif University of Technology
2013
Abstract
In this work a microgrid is established within the geographical perspective of interest. The characteristics of the grid and its urban are employed to determine the candidate points for establishment of EV charging stations. The investment costs and operation costs are calculated for each station realizing the required constraints. This process resulted in optimum selection of EV stations. The optimization is achieved based on two different types of preliminary assumptions. In the first one, it is assumed to have only one station, while in the second one possibility of having multi-stations is considered. Using the total investment and operation costs as the objective function of...
An improved simulated annealing algorithm in fracture network modeling
, Article Journal of Natural Gas Science and Engineering ; Volume 33 , 2016 , Pages 538-550 ; 18755100 (ISSN) ; Masihi, M ; Sharif University of Technology
Elsevier
Abstract
Fracture network modeling is a crucial step in development of hydrocarbon resources. For proposing development plan and design of stimulation operations fracture network should be known. This paper proposes a new improved simulated annealing algorithm for the problem of fracture network modeling. This algorithm improves computation performance without degrading solution quality so much by incorporating a method for estimation of the initial value of temperature-like parameter, using an adaptive Markov chain length (inner iterations) and suggesting a new fast and adaptive annealing schedule. Masihi et al. (2007) proposed an objective function for fracture network modeling based on mechanism...
Pedal: Power-delay product objective function for internet of things applications
, Article 34th Annual ACM Symposium on Applied Computing, SAC 2019, 8 April 2019 through 12 April 2019 ; Volume Part F147772 , 2019 , Pages 892-895 ; 9781450359337 (ISBN) ; Mohammad Salehi, A. A ; Shirbeigi, M ; Hosseini Monazzah, A. M ; Ejlali, A ; ACM Special Interested Group on Applied Computing ; Sharif University of Technology
Association for Computing Machinery
2019
Abstract
The increasing trend in the number of smart connected devices has turned the routing procedure as one of the major challenges in IoT infrastructures. The Routing Protocol for Low Power and Lossy Networks (RPL) was introduced to satisfy different IoT application requirements through Objective Functions (OF). Although there have been several studies on introducing new OFs in order to fulfill specific IoT characteristics, e.g., energy and delay efficiency, reliability, and stability, but still there is a lack of novel OFs which fulfill the IoT application requirements in terms of both, the performance and the power consumption simultaneously. In this paper, we have proposed PEDAL, an OF which...
Optimal placement of switching and protection devices in radial distribution networks to enhance system reliability using the AHP-PSO method
, Article Turkish Journal of Electrical Engineering and Computer Sciences ; Volume 27, Issue 1 , 2019 , Pages 181-196 ; 13000632 (ISSN) ; Fotuhi Firuzabad, M ; Sharif University of Technology
Turkiye Klinikleri Journal of Medical Sciences
2019
Abstract
This paper presents a new method to determine the optimal number and locations of autorecloser and sectionalizer switches (AR/S) in distribution networks. The costs of AR/S investment, switch maintenance, and undistributed energy as well as reliability coefficients are considered in the objective function. Reliability parameters such as SAIFI, SADI, MAIFI, and ENS are evaluated in the case study system. As a new method, the weights of the reliability parameters are obtained by decision-makers using the analytical hierarchy process (AHP). The optimal size, type, and location of automatic switches are determined by minimizing the objective function using the particle swarm optimization (PSO)...
Pedal: Power-delay product objective function for internet of things applications
, Article 34th Annual ACM Symposium on Applied Computing, SAC 2019, 8 April 2019 through 12 April 2019 ; Volume Part F147772 , 2019 , Pages 892-895 ; 9781450359337 (ISBN) ; Mohammad Salehi, A. A ; Shirbeigi, M ; Hosseini Monazzah, A. M ; Ejlali, A ; ACM Special Interested Group on Applied Computing ; Sharif University of Technology
Association for Computing Machinery
2019
Abstract
The increasing trend in the number of smart connected devices has turned the routing procedure as one of the major challenges in IoT infrastructures. The Routing Protocol for Low Power and Lossy Networks (RPL) was introduced to satisfy different IoT application requirements through Objective Functions (OF). Although there have been several studies on introducing new OFs in order to fulfill specific IoT characteristics, e.g., energy and delay efficiency, reliability, and stability, but still there is a lack of novel OFs which fulfill the IoT application requirements in terms of both, the performance and the power consumption simultaneously. In this paper, we have proposed PEDAL, an OF which...
A Reliable Mobility-Aware RPL Objective Function for IoT Applications
, M.Sc. Thesis Sharif University of Technology ; Ejlali, Alireza (Supervisor)
Abstract
Internet of Things (IoT) is one of the most emerging fields in the computer science context. It is predicted that more than 9 billion devices will be connected to IoT networks by 2025. Considering the specifications of IoT devices such as low battery capacity and small memory, these networks face major challenges in energy consumption and reliability. One of the most important elements which have an indisputable effect on network efficiency is routing protocol. In this manner, IETF presented RPL in 2012. It is designed to create a robust network among IoT devices.Although RPL performs well in static networks, it is not designed originally for mobile networks and it has serious flaws in that...
Energy-Aware Routing in Internet of Things
, Ph.D. Dissertation Sharif University of Technology ; Ejlali, Alireza (Supervisor)
Abstract
Internet of Things (IoT) is a communicative infrastructure, which establishes IP-based connections between many smart devices with limited energy supplies. The gathering of such an enormous number of connected devices would impose many challenges, with routing the most important issue. Standardization of the IPv6 Routing Protocol for Low-power and Lossy Networks (RPL) was a major step towards fulfilling the IoT routing requirements. The key element in determining the routing policies and creation of the topology in RPL is the objective function. According to our studies, more than 97% of the consumed energy of a node in wireless networks is due to transceiver activities. On the other hand,...
A new approach for AC state estimation based on a linear network model
, Article ELECO 2013 - 8th International Conference on Electrical and Electronics Engineering ; 2013 , Pages 117-121 ; 9786050105049 (ISBN) ; Fotuhi Firuzabad, M ; Aminifar, F ; Lehtonen, M ; Ozdemir, A ; Sharif University of Technology
Abstract
This paper presents a new and efficient formulation for the state estimation (SE) which can be solved in one single shot of computation. The proposed approach adopts line flows and the square of voltage magnitudes as the problem state variable and considers both active and reactive power quantities. The objective function is to minimize the weighted sum of the least square values of measurement residuals. The nonlinearity associated with line losses is left by assuming these values as slack variables. Numerical studies are conducted through two standard networks. In order to compare the performance of the proposed method, the conventional weighted least square (WLS) state estimation with...
Unit commitment using particle swarm-based-simulated annealing optimization approach
, Article 2007 IEEE Swarm Intelligence Symposium, SIS 2007, Honolulu, HI, 1 April 2007 through 5 April 2007 ; 2007 , Pages 297-302 ; 1424407087 (ISBN); 9781424407088 (ISBN) ; Hajian, M ; Zamani, M ; Sharif University of Technology
2007
Abstract
In this paper, a new approach based on hybrid Particle Swarm-Based- Simulated Annealing Optimization (PSO-B-SA) for solving thermal unit commitment (UC) problems is proposed. The PSO-B-SA presented in this paper solves the two sub-problems simultaneously and independently; unit-scheduled problem that determines on/off status of units and the economic dispatch problem for production amount of generating units. Problem formulation of UC is defined as minimization of total objective function while satisfying all the associated constraints such as minimum up and down time, production limits and the required demand and spinning reserve. Simulation results show that the proposed approach can...
Mechanism synthesis for path generation using the curvature based - Deflection based objective function
, Article WSEAS Transactions on Systems ; Volume 5, Issue 12 , 2006 , Pages 2839-2843 ; 11092777 (ISSN) ; Jafarijashemi, G ; Mamduhi, M ; Aghmioni, A. N ; Zohoor, H ; Sharif University of Technology
2006
Abstract
This paper proposed a new curvature based path-description method for path-generation of planar mechanism, in which the position vector of a point on coupler, which follows most closely a predefined path, is directly calculated as a function of coupler motion properties. In addition this curvature based method makes it possible to define an objective function independent of rotation and translation transformations. Therefore, in this method, initial position, orientation, and coupler point vector parameters are not the optimization variable. These five parameters could be calculated as a function of other design parameters and they are found when these optimal values are obtained. Reducing...
A fast flux search controller for DTC based induction motor drives
, Article PESC Record - IEEE Annual Power Electronics Specialists Conference ; Volume 2005 , 2005 , Pages 739-744 ; 02759306 (ISSN); 0780390334 (ISBN); 9780780390331 (ISBN) ; Zolghadri, M. R ; Emadi, A ; Sharif University of Technology
2005
Abstract
In this paper, a flux search controller is proposed to increase the efficiency of a direct torque controlled induction motor with light load. The reference flux value is determined through a two stage minimization algorithm with the amplitude of the stator current as the objective function. In the transient state, a great flux step is used to speed up the convergence. In the steady state, a noise cancellation algorithm is used to let using small flux step and improves the steady state behavior of flux controller. Simulation and experimental confirm the fast dynamics of the proposed method and its superiority compared to the other optimal flux search controllers. © 2005 IEEE
Short-term resilience-oriented enhancement in smart multiple residential energy system using local electrical storage system, demand side management and mobile generators
, Article Journal of Energy Storage ; Volume 52 , 2022 ; 2352152X (ISSN) ; Mohammadnezhad Shourkaei, H ; Fotuhi Firuzabad, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Recently, many investigations have been studied on the effects of the uncommon extreme events like hurricanes in electrical distribution grids. These events leads to damage to distribution grid equipments, and they are cause widespread blackouts. This paper presents short-term resilience enhancement of the residential sections against hurricane at day-ahead. The lines outage in the electrical distribution grid is implemented as stochastic modeling by hurricane. The resilience enhancement is done in the multiple energy systems such as integrated gas, heat and electrical. The three-stage multi-objective functions optimization is proposed for resilience-oriented enhancement. The proposed...
History Matching using Streamline Simulation
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor) ; Badakhshan, Amir (Supervisor) ; Kamali, Mohammad Reza (Supervisor)
Abstract
Management decisions, Enhanced Oil Recovery, and reservoir development plans in petroleum industries are based on predictions by reservoir simulation. Due to uncertainties in model parameters or engineering assumptions, the simulation results are not accurate, while they are correct. One remedy is to match simulation results with engineering measurements, typically pressure and flow rate, by adjusting model parameters. In Reservoir Engineering literature, this is called History Matching and is an optimization problem. Common methods of history matching are based on finite difference simulation, and therefore have a very low speed. In addition, these methods usually ignore Geostatistical...
, M.Sc. Thesis Sharif University of Technology ; Shadrokh, Shahram (Supervisor)
Abstract
In this thesis a multi-mode resource constrained project scheduling problem with considering project robustness,length of critical path and total quality of project is solved. Also we tried to propose a new mathematical model for this problem and we used both renewable and non-renewable resource constrained.The function is multi-objective so we couldn’t use classic optimization methods to reach globally or locally optimum solutions,then we used a multi-criteria optimization method to solve the problem.with respect to the computational complexity of problem we proposed a multi-objective metaheuristic (DE) algorithm to get to dominated optimal solutions.in our metaheuristic method particular...
Optimization of Die Profile in Screw Extrusion Process for an Arbitrary Profile by Considering Viscoelastic Effects of the Material
, M.Sc. Thesis Sharif University of Technology ; Asghari, Mohsen (Supervisor)
Abstract
In this thesis, equations related to large deformation of a polymer were derived by considering viscoelastic effects. To express type of material behavior which includes elastoplastic and viscoelastic property at the same time, two-layer viscoplastic model was used. An axisymmetric model was used for modeling problem in finite element software. By derivation of parameters related to two layer model and entering them in finite element software and also entering other properties required to model the forming process, modeling was performed by special profile connecting input and output sections. Due to favorable properties of spline functions, profiles used in die geometry, were selected from...
Simulation of Saccharomyces Cerevisiae Batch Culture Behavior Using Dynamic Flux Analysis and Nonlinear Objective Functions
, M.Sc. Thesis Sharif University of Technology ; Farhadi, Fathollah (Supervisor) ; Pishvaei, Mahmoud Reza (Supervisor)
Abstract
There are many limitations to determine relationships within biological systems. Among the limitations of these systems, one can consider the lack of sufficient information about them, such as the complete knowledge of many networks, the lack of reaction information, the complexity of the analysis of these reactions, etc. One of the methods to analyze these systems is called flux balance analysis. This method consists of three parts: objective function, equal constraints and unequal constraints. Among the features available in this method, we can mention less need for experimental information and no need for high processing systems. In order to determine the objective functions in this...
Proposing an Energy-Aware Objective Function Based on Reinforcement Learning for Mobile IoT Networks
, M.Sc. Thesis Sharif University of Technology ; Ejlali, Alireza (Supervisor)
Abstract
The presence of IoT has been increased in different aspects of human life. Due to the increasing trend in the number of smart connected devices, routing has become a major challenge in loT systems. Furthermore, due to the energy-constrained embedded devices in the network, which are usually battery-powered, and considering that %97 of the node's energy consumption is due to activities associated with the transceiver module, the energy-aware routing is significantly important. In this regard, the IPv6 routing protocol for low-power and lossy networks (RPL) was standardized to be adopted in IoT infrastructure. Due to the increasing interest in mobile IoT applications in recent years and...
Dictionary learning for sparse representation: A novel approach
, Article IEEE Signal Processing Letters ; Volume 20, Issue 12 , 2013 , Pages 1195-1198 ; 10709908 (ISSN) ; Babaie Zadeh, M ; Jutten, C ; Sharif University of Technology
2013
Abstract
A dictionary learning problem is a matrix factorization in which the goal is to factorize a training data matrix, Y, as the product of a dictionary, D, and a sparse coefficient matrix, X, as follows, Y ≈ DX. Current dictionary learning algorithms minimize the representation error subject to a constraint on D (usually having unit column-norms) and sparseness of X. The resulting problem is not convex with respect to the pair (D, X). In this letter, we derive a first order series expansion formula for the factorization, DX. The resulting objective function is jointly convex with respect to D and X. We simply solve the resulting problem using alternating minimization and apply some of the...