The minmax multiple traveling salesman problem involves minimizing the longest tour among a set of tours. The problem is of great practical interest because it can be used to formulate several real-life applications. ...
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This report reviews an example of acoustic positioning of partial discharges (PD) in the tank of a high-voltage oil-filled transformer. The literature review confirms the importance of PD monitoring and justifies the ...
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ISBN:
(数字)9798350386028
ISBN:
(纸本)9798350386035
This report reviews an example of acoustic positioning of partial discharges (PD) in the tank of a high-voltage oil-filled transformer. The literature review confirms the importance of PD monitoring and justifies the feasibility of positioning discharge activity centers. The precise positioning of PD sources is required to determine the location of insulation defects. The authors provide brief information on the development of PD positioning methods and note that their practical application has been insufficiently covered in publications. They present the results of electromagnetic and acoustic PD positioning in a 110 kV transformer. Some details are provided on the devices and measurement methods used, including the localization of areas with increased PD intensity using one acoustic sensor and the subsequent center localization through the installation of 4 sensors at even intervals. The authors provide PD signals and defect impulses received from each of the sensors and demonstrate the difference in the registration time of these signals. They explain the principle behind PD center positioning, which is determined considering delays in signal reception. The authors demonstrate the usage of the Inva (Portable) software for the processing and visualization of acoustic positioning results. They note that changes in the propagation rate of acoustic waves in a heterogeneous medium result in the reduced accuracy of results. The authors also outline the prospects of the research into the elimination of occurring defects.
Various frequency-domain integral formulas are available and can be used to characterize fundamental performance limitations and inherent performance tradeoffs in feedback systems design, and often they appear unrelat...
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Various frequency-domain integral formulas are available and can be used to characterize fundamental performance limitations and inherent performance tradeoffs in feedback systems design, and often they appear unrelated. The most exemplary result in this spirit is the Bode sensitivity integral relation. Yet in an interesting finding, in this paper we show that the Bode sensitivity integral can serve as a unifier to link all other integral formulas, including the complementary sensitivity integrals, the Poisson integrals, and the Bode gain-phase integrals, though traditionally they were derived in different ways and have been used for different performance objectives.
The LV dc system is a relatively new trend in the distribution sector, which seems to grow widely in the near future due to its promising advantages. In this context, LV dc protection and grounding are challenging iss...
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ISBN:
(数字)9798350318265
ISBN:
(纸本)9798350318272
The LV dc system is a relatively new trend in the distribution sector, which seems to grow widely in the near future due to its promising advantages. In this context, LV dc protection and grounding are challenging issues. Although the galvanically isolated connection mode of dc nanogrid to the ac grid has high reliability, the leakage current can still be injected into the ac grid through the interwinding capacitors and the insulation resistance between the primary and secondary windings of the transformer. The way of grounding the dc nanogrid can also be a determining factor in the leakage current and its dc components. This study deals with the leakage current in the galvanically isolated dc nanogrid. Then, it examines the dc leakage current and its relationship with the dc nanogrid grounding and finally provides solutions to remove the dc components in the leakage current.
In this paper, we consider the unconstrained distributed optimization problem, in which the exchange of information in the network is captured by a directed graph topology, thus, nodes can only communicate with their ...
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In this paper, we consider the unconstrained distributed optimization problem, in which the exchange of information in the network is captured by a directed graph topology, thus, nodes can only communicate with their neighbors. Additionally, in our problem, the communication channels among the nodes have limited bandwidth. In order to alleviate this limitation, quantized messages should be exchanged among the nodes. For solving this distributed optimization problem, we combine a gradient descent method with a distributed quantized consensus algorithm (which requires the nodes to exchange quantized messages and converges in a finite number of steps). Specifically, at every optimization step, each node (i) performs a gradient descent step (i.e., subtracts the scaled gradient from its current estimate), and (ii) performs a finite-time calculation of the quantized average of every node's estimate in the network. As a consequence, this algorithm approximately mimics the centralized gradient descent algorithm. We show that our algorithm asymptotically converges to a neighborhood of the optimal solution with linear convergence rate. The performance of the proposed algorithm is demonstrated via simple illustrative examples.
The field of information security is constantly evolving, and new threats appear every day. To ensure that organizations remain protected from these threats, it is important to have a reliable information security aud...
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Multi-robot systems have increasingly become instrumental in tackling coverage problems. However, the challenge of optimizing task efficiency without compromising task success still persists, particularly in expansive...
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ISBN:
(数字)9798350384574
ISBN:
(纸本)9798350384581
Multi-robot systems have increasingly become instrumental in tackling coverage problems. However, the challenge of optimizing task efficiency without compromising task success still persists, particularly in expansive, unstructured scenarios with dense obstacles. This paper presents an innovative, decentralized Voronoi-based coverage control approach to reactively navigate these complexities while guaranteeing safety. This approach leverages the active sensing capabilities of multi-robot systems to supplement GIS (Geographic Information System), offering a more comprehensive and real-time understanding of environments like post-disaster. Based on point cloud data, which is inherently non-convex and unstructured, this method efficiently generates collision-free Voronoi regions using only local sensing information through spatial decomposition and spherical mirroring techniques. Then, deadlock-aware guided map integrated with a gradient-optimized, centroid Voronoi-based coverage control policy, is constructed to improve efficiency by avoiding exhaustive searches and local sensing pitfalls. The effectiveness of our algorithm has been validated through extensive numerical simulations in high-fidelity environments, demonstrating significant improvements in task success rate, coverage ratio, and task execution time compared with others.
Similarity transformation problems are important in robotic instrumentation and computer vision based measurements since in many cases the information of visually observed scene scale is unknown and must be restored f...
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Similarity transformation problems are important in robotic instrumentation and computer vision based measurements since in many cases the information of visually observed scene scale is unknown and must be restored for accurate 3-dimensional reconstruction. In existing solvers, the scale is often considered as a scalar, i.e., isotropic, which may be invalid for anisotropic-scale setups. This paper exploits some mathematical coincidences that will lead to efficient solution to these problems. Possible further applications also include hand-eye calibration and structure-from-motion. We revisit pose estimation problems within the framework of similarity transformation, the one that considers scale-stretching, rotation and translation simultaneously. Two major problems are taken into account, i.e., the scale-stretching point-cloud registration and perspective-n-points (PnP). It has been found out that these two problems are quite similar. Moreover, we solve the anisotropic-scale registration problem that is important and is a remaining unsolved one in previous literatures. To compute the globally optimal solution of these non-convex problems, algebraic solution is obtained to compute all local minima using computationally efficient methods. The designed algorithm is deployed for robotic-arm pose estimation. We also extend the algorithm for solving the problem of robust magnetometer calibration. Visual pose experiments verify the superiority of the proposed method compared with representatives, including P3P, Lambda-Twist P3P and EPnP, which can be reproduced by repository in https://***/zarathustr/APnP. IEEE
The development of quantum technologies relies on creating and manipulating quantum systems of increasing complexity, with key applications in computation, simulation, and sensing. This poses severe challenges in effi...
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Attitude control and stabilization of micro-satellites is a nontrivial problem due to the highly nonlinear and multivariable structure of the satellites'state-space *** this paper,a novel nonlinear optimal(H-infin...
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Attitude control and stabilization of micro-satellites is a nontrivial problem due to the highly nonlinear and multivariable structure of the satellites'state-space *** this paper,a novel nonlinear optimal(H-infinity)control approach is developed for this control *** dynamic model of the satellite's attitude dynamics undergoesfirst approximate linearization around a temporary operating point which is updated at each iteration of the control *** linearization process relies on first-order Taylor series expansion and on the computation of the Jacobian matrices of the state-space model of the satellite's attitude *** the approximately linearized description of the satellite's attitude a stabilizing H-infinity feedback controller is *** compute the controller's feedback gains,an algebraic Riccati equation is solved at each time-step of the control *** stability properties of the control scheme are proven through Lyapunov *** is also demonstrated that the control method retains the advantages of linear optimal control that is fast and accurate tracking of the reference setpoints under moderate variations of the control inputs.
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