This paper is concerned with the inference of marginal densities based on MRF models. The optimization algorithms for continuous variables are only applicable to a limited number of problems, whereas those for discret...
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ISBN:
(纸本)9781467364102
This paper is concerned with the inference of marginal densities based on MRF models. The optimization algorithms for continuous variables are only applicable to a limited number of problems, whereas those for discrete variables are versatile. Thus, it is quite common to convert the continuous variables into discrete ones for the problems that ideally should be solved in the continuous domain, such as stereo matching and optical flow estimation. In this paper, we show a novel formulation for this continuous-discrete conversion. The key idea is to estimate the marginal densities in the continuous domain by approximating them with mixtures of rectangular densities. Based on this formulation, we derive a mean field (MF) algorithm and a belief propagation (BP) algorithm. These algorithms can correctly handle the case where the variable space is discretized in a non-uniform manner. By intentionally using such a non-uniform discretization, a higher balance between computational efficiency and accuracy of marginal density estimates could be achieved. We present a method for actually doing this, which dynamically discretizes the variable space in a coarse-to-fine manner in the course of the computation. Experimental results show the effectiveness of our approach.
This paper considers the problem of evaluating robust control invariant (RCI) sets for linear discrete-time systems subject to state and input constraints as well as additive disturbances. An RCI set has the property ...
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ISBN:
(纸本)9781479978878
This paper considers the problem of evaluating robust control invariant (RCI) sets for linear discrete-time systems subject to state and input constraints as well as additive disturbances. An RCI set has the property that if the system state is inside the set at any one time, then it is guaranteed to remain in the set for all future times using a predefined state feedback control law. This problem is important in many control applications. We present a numerically efficient algorithm for the computation of full-complexity polytopic RCI sets. Farkas' Theorem is first used to derive necessary and sufficient conditions for the existence of an admissible polytopic RCI set in the form of nonlinear matrix inequalities. An Elimination Lemma is then used to derive sufficient conditions, in the form of linear matrix inequalities, for the existence of the solution. An optimization algorithm to approximate maximal RCI sets is also proposed. Numerical examples are given to illustrate the effectiveness of the proposed algorithm.
In this paper, new planar spiral antennas for passive RFID tag application at UHF band are designed and optimized using the Artificial Bee Colony (ABC) algorithm. The optimization goals are antenna size minimization, ...
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ISBN:
(纸本)9781467321877
In this paper, new planar spiral antennas for passive RFID tag application at UHF band are designed and optimized using the Artificial Bee Colony (ABC) algorithm. The optimization goals are antenna size minimization, gain maximization and conjugate matching. The antenna dimensions were optimized and evaluated using ABC in conjunction with commercial EM software. Furthermore, a theoretical analysis of the spiral antennas was performed. The input impedance of the printed spiral, was calculated approximately via the Transmission Line Model and the electromotive force induced along the spirals. The theoretical results seem to be in good agreement with the EM solver results. The optimization results produced show that ABC is a powerful optimization algorithm that can be efficiently applied to tag antenna design problems. RFID tags with dimensions less than 4cm, gain that reaches the value of 2 dBi and read distance about 11.7m were among those obtained by the algorithm.
A new Kalman filter based signal estimation concept for active vehicle suspension control is presented in this paper considering the nonlinear damper characteristic of a vehicle suspension setup. The application of a ...
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ISBN:
(纸本)9781424474264
A new Kalman filter based signal estimation concept for active vehicle suspension control is presented in this paper considering the nonlinear damper characteristic of a vehicle suspension setup. The application of a multi-objective genetic optimization algorithm for the tuning of the estimator shows that three parallel Kalman filters enhance the estimation performance for the variables of interest (states, dynamic wheel load and road profile). The Kalman filter structure is validated in simulations and on a testrig for an active suspension configuration using measurements of real road profiles as disturbance input. The advantages of the concept are its low computational effort compared to Extended or Unscented Kalman filters and its good estimation accuracy despite the presence of nonlinearities in the suspension setup.
We propose a simple and optimal algorithm, BackMC, for local PageRank estimation in undirected graphs: given an arbitrary target node t in an undirected graph G comprising n nodes and m edges, BackMC accurately estima...
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Genetic algorithms have established their capability for solving many complex optimization problems. Even as good solutions are produced, the user’s understanding of a problem is not necessarily improved, which can l...
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The goal of this paper is to derive a small perturbation analysis for networks subject to random changes of a small number of edges. Small perturbation theory allows us to derive, albeit approximate, closed form expre...
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ISBN:
(纸本)9781538646595
The goal of this paper is to derive a small perturbation analysis for networks subject to random changes of a small number of edges. Small perturbation theory allows us to derive, albeit approximate, closed form expressions that make possible the theoretical statistical characterization of the network topology changes. The analysis is instrumental to formulate a graph-based optimization algorithm, which is robust against edge failures. In particular, we focus on the optimal allocation of the overall transmit powers in wireless communication networks subject to fading, aimed at minimizing the variation of the network connectivity, subject to a constraint on the overall power necessary to maintain network connectivity.
optimization is employed in solutions of many problems today. optimization is described as finding the most suitable alternative among many others under the given constraints. Meta-heuristic algorithms used in solutio...
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ISBN:
(纸本)9781509004256
optimization is employed in solutions of many problems today. optimization is described as finding the most suitable alternative among many others under the given constraints. Meta-heuristic algorithms used in solutions of the problems are developed upon the behaviors of living creatures in the nature. One of these is Bat Algorithm (BA), an optimization method based on swarm intelligence. BA is a numerical optimization technique developed in recent times. In this paper, it is aimed at improving Bat Algorithm (IBA) by using Differential Evolution Algorithm population strategy instead of population generation method of BA. IBA was tested on 17 benchmark functions with different characteristics. Suggested method has been seen to exhibit better results compared to the original BA.
This article approaches about electrostatic discharge algorithm (ESDA) which is applied to find the optimization problems of economic load dispatch (ELD). This algorithm is tested and applied for the systems of 6 and ...
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ISBN:
(数字)9781728143620
ISBN:
(纸本)9781728143637
This article approaches about electrostatic discharge algorithm (ESDA) which is applied to find the optimization problems of economic load dispatch (ELD). This algorithm is tested and applied for the systems of 6 and 40 units. Wind power is included with the both systems for minimizing the cost. Now-a-days wind energy is getting more importance because wind energy is easily accessible all over the world. Both units of 6 and 40 are tested with and without wind energy respectively. The tested results are compared with the recent available optimization algorithms and electrostatic discharge algorithm proves itself as more effective optimization technique than others.
Population-based optimization algorithms are widely used in multiple research areas to optimize different kinds of problems. Commonly, they have been successfully applied to low and medium size search spaces in order ...
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ISBN:
(纸本)9781457702501
Population-based optimization algorithms are widely used in multiple research areas to optimize different kinds of problems. Commonly, they have been successfully applied to low and medium size search spaces in order to tune or adjust several design parameters. Unfortunately, population-based algorithms can require too much CPU time to find a nearly optimal solution as the number of dimensions of the problem to tackle increases significantly. Usually, mathematical or physical-inspired techniques have been applied to improve the success rate as well as the speed of convergence of population-based methods in a high dimensional framework. An alternative choice is to allocate the individuals of the population in an efficient way during the initialization stage of the algorithm considering two possibilities: placing individuals as close as possible to a global optimum or uniformly distributed over the search space. In this work, three different initialization strategies, the orthogonal array initialization, a chaotic technique and the opposition based initialization have been considered and appropriately combined with the heuristic particle swarm optimization (PSO) algorithm. Results comparing the modified PSO algorithm when applied to optimize frequency selective surfaces (FSS) and planar arrays for WiMAX applications are included.
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