| 1. |
- Gholami, Amir Hossein, et al.
(författare)
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Decentralized Optimization in Scheduling Virtual Power Plant (VPP)
- 2023
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Ingår i: 2023 31st International Conference on Electrical Engineering, ICEE 2023. - : Institute of Electrical and Electronics Engineers (IEEE). - 9798350312560 ; , s. 420-425
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Konferensbidrag (refereegranskat)abstract
- The scheduling of virtual power plants (VPPs) has received much attention in the last few years. VPP refers to the integration of several power plant units together, which is considered as a single power plant. In this paper, three VPPs are considered, each of which includes different power plant units and must supply the desired load. Besides supplying the desired load, they should maximize their profit. Decentralized optimization method has been used to optimize these three VPPs. The reason for using decentralized method is to increase network security and also to not need a central computer. On the other hand, using the decentralized optimization method increases the speed of problem solving. Finally, the obtained results have been compared with the centralized method. The simulations show that almost the same result has been obtained by using different optimization methods. These results increase the tendency to use decentralized methods in VPPs.
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| 2. |
- Gholami, Mohammad Reza, 1976, et al.
(författare)
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RSS-Based Sensor Localization in the Presence of Unknown Channel Parameters
- 2013
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Ingår i: IEEE Transactions on Signal Processing. - 1941-0476 .- 1053-587X. ; 61:15, s. 3752-3759
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Tidskriftsartikel (refereegranskat)abstract
- This correspondence studies the received signal strength-based localization problem when the transmit power or path-loss exponent is unknown. The corresponding maximum-likelihood estimator (MLE) poses a difficult nonconvex optimization problem. To avoid the difficulty in solving the MLE, we use suitable approximations and formulate the localization problem as a general trust region subproblem, which can be solved exactly under mild conditions. Simulation results show a promising performance for the proposed methods, which also have reasonable complexities compared to existing approaches.
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| 3. |
- Monir Vaghefi, Sayed Reza, 1985, et al.
(författare)
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Bearing-only target localization with uncertainties in observer position
- 2010
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Ingår i: IEEE international Workshop on Advances in positioning and location-enabled communications (in conjection with PIMRC'10). - 9781424491162 ; , s. 238-242
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Konferensbidrag (refereegranskat)abstract
- In this paper, the bearing-only target localizationproblem when the observer positions are subject to error is investigated.In this problem, the angle of arrival of the transmittedsignal between target and observer are used to estimate the targetposition. It is assumed that not only the bearing measurementsare corrupted by noise but also the exact position of observer isnot available to the estimator. The accuracy of estimated locationof target depends on the reliability of information from theobserver position. Therefore, the previously published algorithmsconsidering only the bearing measurement noise do not meet theexpected performance when the observer positions are subjectto error. The maximum likelihood, the least squares and totalleast square algorithms and a new method of localization basedon weighted total least squares approach are developed for thisproblem. The corresponding Cram´er-Rao lower bound (CRLB) isderived for this problem. Computer simulations are performed toevaluate the performance of the proposed algorithms. Simulationresults show that the new method can attain the CRLB forsufficiently high SNR.
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| 4. |
- Monir Vaghefi, Sayed Reza, 1985, et al.
(författare)
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Cooperative Received Signal Strength-Based Sensor Localization with Unknown Transmit Powers
- 2013
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Ingår i: IEEE Transactions on Signal Processing. - 1941-0476 .- 1053-587X. ; 61:6, s. 1389-1403
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Tidskriftsartikel (refereegranskat)abstract
- Cooperative localization (also known as sensor network localization) using received signal strength (RSS) measurements when the source transmit powers are different and unknown is investigated. Previous studies were based on the assumption that the transmit powers of source nodes are the same and perfectly known which is not practical. In this paper, the source transmit powers are considered as nuisance parameters and estimated along with the source locations. The corresponding Cramer-Rao lower bound (CRLB) of the problem is derived. To find the maximum likelihood (ML) estimator, it is necessary to solve a nonlinear and nonconvex optimization problem, which is computationally complex. To avoid the difficulty in solving the ML estimator, we derive a novel semidefinite programming (SDP) relaxation technique by converting the ML minimization problem into a convex problem which can be solved efficiently. The algorithm requires only an estimate of the path loss exponent (PLE). We initially assume that perfect knowledge of the PLE is available, but we then examine the effect of imperfect knowledge of the PLE on the proposed SDP algorithm. The complexity analyses of the proposed algorithms are also studied in detail. Computer simulations showing the remarkable performance of the proposed SDP algorithm are presented.
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| 5. |
- Monir Vaghefi, Sayed Reza, 1985, et al.
(författare)
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RSS-based sensor localization with unknown transmit power
- 2011
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Ingår i: ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings. - 1520-6149. - 9781457705397 ; , s. 2480-2483
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Konferensbidrag (refereegranskat)abstract
- Received signal strength (RSS)-based single source localization when there is not a prior knowledge about the transmit power of the source is investigated. Because of nonconvex behavior of maximum likelihood (ML) estimator, convoluted computations are required to achieve its global minimum. Therefore, we propose a novel semidefinite programming (SDP) approach by approximating ML problem to a convex optimization problem which can be solved very efficiently. Computer simulations show that our proposed SDP has a remarkable performance very close to ML estimator. Linearizing RSS model, we also derive the partly novel least squares (LS) and weighted total least squares (WTLS) algorithms for this problem. Simulations illustrate that WTLS improves the performance of LS considerably.
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| 6. |
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| 7. |
- Davide, Dardari, et al.
(författare)
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Innovative Signal Processing Techniques for Wireless Positioning
- 2012
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Ingår i: Satellite and Terrestrial Radio Positioning Techniques, Davide Dardari, Emanuela Falletti, and Marco Luise, editors. Oxford, Academic Press. - 9780123820846 ; , s. 207-315
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 8. |
- Gezici, S., et al.
(författare)
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Optimal jammer placement in wireless localization networks
- 2015
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Ingår i: IEEE Workshop on Signal Processing Advances in Wireless Communications, SPAWC. - : IEEE conference proceedings. - 9781479919307 ; , s. 665-669
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Konferensbidrag (refereegranskat)abstract
- The optimal jammer placement problem is proposed for a wireless localization network, where the aim is to degrade the accuracy of locating target nodes as much as possible. In particular, the optimal location of a jammer node is obtained in order to maximize the minimum of the Cramér-Rao lower bounds for a number of target nodes under location related constraints for the jammer node. Theoretical results are derived to specify scenarios in which the jammer node should be located as close to a certain target node as possible, or the optimal location of the jammer node is determined by two or three of the target nodes. In addition, explicit expressions for the optimal location of the jammer node are derived in the presence of two target nodes. Numerical examples are presented to illustrate the theoretical results.
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| 9. |
- Gezici, Sinan, et al.
(författare)
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Optimal Jammer Placement in Wireless Localization Systems
- 2016
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Ingår i: IEEE Transactions on Signal Processing. - 1053-587X .- 1941-0476. ; 64:17, s. 4534-4549
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the optimal jammer placement problem is proposed and analyzed for wireless localization systems. In particular, the optimal location of a jammer node is obtained by maximizing the minimum of the Cramer-Rao lower bounds (CRLBs) for a number of target nodes under location related constraints for the jammer node. For scenarios with more than two target nodes, theoretical results are derived to specify conditions underwhich the jammer node is located as close to a certain target node as possible, or the optimal location of the jammer node is determined by two of the target nodes. Also, explicit expressions are provided for the optimal location of the jammer node in the presence of two target nodes. In addition, in the absence of distance constraints for the jammer node, it is proved, for scenarios with more than two target nodes, that the optimal jammer location lies on the convex hull formed by the locations of the target nodes and is determined by two or three of the target nodes, which have equalized CRLBs. Numerical examples are presented to provide illustrations of the theoretical results in different scenarios.
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| 10. |
- Gezici, Sinan, et al.
(författare)
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Optimal Jamming of Wireless Localization Systems
- 2015
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Ingår i: 2015 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATION WORKSHOP. - : IEEE. - 9781467363051 ; , s. 877-882
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Konferensbidrag (refereegranskat)abstract
- In this study, optimal jamming of wireless localization systems is investigated. Two optimal power allocation schemes are proposed for jammer nodes in the presence of total and peak power constraints. In the first scheme, power is allocated to jammer nodes in order to maximize the average Cramer-Rao lower hound (CRLB) of target nodes whereas in the second scheme the power allocation is performed for the aim of maximizing the minimum CRLB of target nodes. Both schemes are formulated as linear programs, and a closed-form expression is obtained for the first scheme. Also, the full total power utilization property is specified for the second scheme. Simulation results are presented to investigate perlbrmance of the proposed schemes.
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