Browsing by Subject "Optimization"
Now showing items 1-20 of 21
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A Novel Approach for Voltage Control in Electrical Power Distribution Systems
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Publisher and Date:(IEEE, 2018)This paper proposes a novel approach for voltage control in 3-phase unbalanced distribution systems. The approach is based on the change of the magnetizing reactances of the voltage regulators in the system. We used an augmented Lagrangian-based optimization model to determine the optimal settings on a modified IEEE 123 Bus Test System with large PV penetration. Simulations were performed on a minute-based resolution either by controlling regulators or by controlling the magnetizing reactances of ...
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Accurate indoor positioning with ultra-wide band sensors
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Publisher and Date:(Tubitak, 2020)Ultra-wide band is one of the emerging indoor positioning technologies. In the application phase, accuracy and interference are important criteria of indoor positioning systems. Not only the method used in positioning, but also the algorithms used in improving the accuracy is a key factor. In this paper, we tried to eliminate the effects of off-set and noise in the data of the ultra-wide band sensor-based indoor positioning system. For this purpose, optimization algorithms and filters have been ...
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An Adaptive Affinity Matrix Optimization for Locality Preserving Projection via Heuristic Methods for Hyperspectral Image Analysis
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Publisher and Date:(IEEE-Inst Electrıcal Electronıcs Engıneers Inc, 2019)Locality preserving projection (LPP) has been often used as a dimensionality reduction tool for hyperspectral image analysis especially in the context of classification since it provides a projection matrix for embedding test samples to low dimensional space. However, the performance of LPP heavily depends on the optimization of two parameters of the graph affinity matrix: k-nearest neighbor and heat kernel width, when one considers an isotropic kernel. These two parameters might be optimally ...
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Branch outage simulation based contingency screening by gravitational search algorithm
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Publisher and Date:(Praise Worthy Prize Srl, 2012)Power systems contingency analysis is an important issue for electric power system operators. This paper performs branch outage simulation based contingency screening using a bounded network approach. Local constrained optimization problem representing the branch outage phenomena is solved by the gravitational search algorithm. The proposed method is applied to IEEE 14 30 57 and 118 Bus Test systems and its performance from the point of capturing violations is evaluated. In addition false alarms ...
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Coordinated Electric Vehicle Charging With Reactive Power Support to Distribution Grids
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Publisher and Date:(IEEE, 2019)We develop hierarchical coordination frameworks to optimally manage active and reactive power dispatch of number of spatially distributed electric vehicles (EVs) incorporating distribution grid level constraints. The frameworks consist of detailed mathematical models which can benefit the operation of both entities involved i.e. the grid operations and EV charging. The first model comprises of a comprehensive optimal power flow model at the distribution grid level while the second model represents ...
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Double branch outage modeling and its solution using differential evolution method
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Publisher and Date:(2011)Power system operators need to check the system security by contingency analysis which requires power flow solutions repeatedly. AC power flow is computationally slow even for a moderately sized system. Thus fast and accurate outage models and approximated solutions have been developed. This paper adopts a single branch outage model to a double branch outage one. The final constrained optimization problem resulted from modeling is then solved by using differential evolution method. Simulation ...
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Energy trading in Turkish power market through options bileteral agreements and spot market
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Publisher and Date:(Kadir Has University, 2013)in today’s world electricity energy which has a vital place in energy market is irreplaceable in any field because of being the basic entry in production factors and because of continuous increasing demand to electricity thanks to technological development. Especially in our country which has a rapid acceleration for the last decade by reorganizing Electricity Energy Market it is aimed to build a competitive structure in production and retail transactions. Also with the process of development in ...
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Gravitational search algorithm for post-outage bus voltage magnitude calculations
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Publisher and Date:(2010)Branch outage problem is one of the key problems in power system security analysis. This paper solves branch outage problem using a bounded approach. Local constrained optimization problem in the bounded approach is solved by the gravitational search algorithm. Test results of IEEE 14 30 and 118 bus systems are compared to those of ac load flow method in terms of both accuracy and speed.
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Harmony Search Algorithm Based Management of Distributed Energy Resources and Storage Systems in Microgrids
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Publisher and Date:(MDPI, 2020)Microgrids are composed of distributed energy resources (DERs), storage devices, electric vehicles, flexible loads and so on. They may either operate connected to the main electricity grid (on-grid operation) or separated from the grid (islanded operation). The outputs of the renewable energy sources may fluctuate and thus can cause deviations in the voltage magnitudes especially at islanded mode. This may affect the stability of the microgrids. This paper proposes an optimization model to efficiently ...
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Harmony search method based parallel contingency analysis
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Publisher and Date:(2010)Power system security management is one of the key problems in power system analysis. Power system management center operators need to simulate contingencies as fast as possible and take the remedial actions in time. These contingency analyses comprise of the outages of the branches transformers and other power system components. This paper solves branch outage problem using a bounded approach. Harmony search method is used to solve the local constrained optimization problem of the bounded approach. ...
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Joint Optimization of Wireless Network Energy Consumption and Control System Performance in Wireless Networked Control Systems
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Publisher and Date:(IEEE-INST Electrical Electronics Engineers Inc, 2017)Communication system design for wireless networked control systems requires satisfying the high reliability and strict delay constraints of control systems for guaranteed stability with the limited battery resources of sensor nodes despite the wireless networking induced non-idealities. These include non-zero packet error probability caused by the unreliability of wireless transmissions and non-zero delay resulting from packet transmission and shared wireless medium. In this paper we study the ...
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Location and distribution decisions in an earthquake relief network
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Publisher and Date:(Kadir Has University, 2015)In this thesis, a multi-objective mathematical model was developed in order to configure part of the earthquake relief network in Istanbul, Turkey. The aim of the mathematical model was to help decision makers decide on the locations of storage areas for relief aids as well as distribution of relief aids from these areas to temporary shelter areas while minimizing expected total distribution distance, expected total earthquake damage risk factor of storage areas and expected total unsatisfied ...
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Minimum Length Scheduling for Discrete Rate Based Full Duplex Wireless Powered Communication Networks
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Publisher and Date:(Springer, 2019)In this study, we consider a wireless powered communication network where multiple users with radio frequency energy harvesting capabilities communicate to a hybrid energy and information access point in full duplex mode. We characterize an optimization framework for minimum length scheduling to determine the optimal rate adaptation and transmission scheduling subject to energy causality and traffic demand constraints of the users considering discrete-rate transmission model. We first formulate ...
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Municipal solid waste management via mathematical modeling: A case study in Istanbul, Turkey
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Publisher and Date:(Academic Press Ltd- Elsevier Science Ltd, 2019)The prominence of managing municipal solid waste (MSW) in an efficient and effective manner is increasing from day to day. In this paper, the solid waste management (SWM) system of Istanbul is analyzed by applying the techniques from mathematical programming methodology. In this manner, the solutions of the two optimization problems which aim to minimize the total cost and the environmental effects of SWM, respectively, are presented in this study. Additionally, a sensitivity analysis is performed ...
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Municipal solid waste management via mathematical modeling: A case study in İstanbul, Turkey
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Publisher and Date:(Elsevier, 2019)The prominence of managing municipal solid waste (MSW) in an efficient and effective manner is increasing from day to day. In this paper, the solid waste management (SWM) system of İstanbul is analyzed by applying the techniques from mathematical programming methodology. In this manner, the solutions of the two optimization problems which aim to minimize the total cost and the environmental effects of SWM, respectively, are presented in this study. Additionally, a sensitivity analysis is performed ...
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Optimization of Graph Affinity Matrix with Heuristic Methods in Dimensionality Reduction of Hypespectral Images
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Publisher and Date:(IEEE, 2019)Hyperspectral images include hundreds of spectral bands, adjacent ones of which are often highly correlated and noisy, leading to a decrease in classification performance as well as a high increase in computational time. Dimensionality reduction techniques, especially the nonlinear ones, are very effective tools to solve these issues. Locality preserving projection (LPP) is one of those graph based methods providing a better representation of the high dimensional data in the low-dimensional space ...
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Post outage bus voltage calculations for double branch outages
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Publisher and Date:(IEEE, 2012)Secure operation of electrical power systems is vital hence fast and accurate post-outage state calculations are important for contingency analysis. Contingency analysis includes simulations of both the single and double branch outages. This paper presents constrained optimization problem of a recently developed double branch outage model. Harmony search algorithm is used as an optimization tool. IEEE 30 Bus Test system simulation results are given and compared with those of the AC load flow in ...
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Sceheduling Pumped Hydro- Power Resources Under Price and Flow Uncertainty
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Publisher and Date:(Kadir Has University, 2012)Hydroelectric power plants should be preferred since they are environmentally friendly and they have low level of potential risks. Hydroelectric power plants are local resources that are environmentally compatible unpolluted capable of dealing with peak hour requirements highly efficient cost-free of fuel and playing a role as the insurance of energy prices. -- Abstract'dan.
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The operational economics of compressed air energy storage systems under uncertainty
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Publisher and Date:(Pergamon-Elsevier Science Ltd, 2013)A Compressed Air Energy Storage System is a means of storing energy which can then be used when the demand for energy increases. In this system air is compressed in a cavern when power prices are low and this air is used to run a natural gas-fired turbine to generate power when prices go up with the aim of profiting from the price difference. This type of system can independently compress air generate electricity or do both. However the prices of electricity and natural gas fluctuate which directly ...
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Towards Faster Branch Outage Simulations Using Simulated Annealing and Parallel Programming
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Publisher and Date:(IEEE, 2009)Contingency studies such as branch outage and generator outage are among important studies of energy management centers operations. Branch outage modeling on the other hand is one of the basic steps of post-outage state estimation of an electrical power system. Real time implementation of the problem brings the necessity of using high speed methods while providing a reasonable accuracy. This paper presents simulated annealing based solution of the branch outage event which is formulated as a local ...