A neural network-based approach for solving parametric convex optimization problems is presented, where the network estimates the optimal points given a batch of input parameters. The network is trained by penalizing ...
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This paper presents the optimal radome design using optimization algorithm. Design of a radome is, in general, a formidable problem, since the design philosophy needs to take into account the arbitrariness with respec...
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ISBN:
(纸本)9781424420414
This paper presents the optimal radome design using optimization algorithm. Design of a radome is, in general, a formidable problem, since the design philosophy needs to take into account the arbitrariness with respect to the shape of the radome and the incidence angle of the incident wave into the radome. To circumvent this problem, optimization algorithm appears to be a powerful tool. In this article, particle swarm optimization (PSO), which has recently drawn considerable attention in a wide range of applications, is employed for the design of a radome, in which the frequency characteristics of the transmission coefficient of the radome is adopted as the objective function, and the radome wall thickness and the shape of the radome are optimized. In addition, for the PSO algorithm, we introduce a concept analogous to "mutation" in GA so as to enhance the globality of the optimal solution, and call it as MPSO (Mutated PSO). We deal with MPSO, PSO and GA, and report the comparisons and characteristics of the optimized radome.
We present a systematic approach for design of extremum seeking (ES) controllers for a class of uncertain plants that are parameterized with unknown parameters. First, we present results for static plants and show how...
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ISBN:
(纸本)9781424477456
We present a systematic approach for design of extremum seeking (ES) controllers for a class of uncertain plants that are parameterized with unknown parameters. First, we present results for static plants and show how it is possible to combine, under certain general conditions, an arbitrary optimization method with an arbitrary parameter estimation method in order to obtain extremum seeking. Our main results also specify how controller needs to be tuned in order to achieve extremum seeking. Then, we consider dynamic plants and separate our results into the stable plant case and unstable plant case. For each of these cases, we present conditions on general plants, controllers, observers, parameter estimators and optimization algorithms that guarantee semi-global practical convergence to the extremum when controller parameters are tuned appropriately. Our results apply to general nonlinear plants with multiple inputs and multiple parameters.
Quality-Diversity (QD) algorithms have exhibited promising results across many domains and applications. However, uncertainty in fitness and behaviour estimations of solutions remains a major challenge when QD is used...
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The approximation of a high-dimensional vector by a small combination of column vectors selected from a fixed matrix has been actively debated in several different disciplines. In this paper, a sampling approach based...
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ISBN:
(纸本)9781509018918
The approximation of a high-dimensional vector by a small combination of column vectors selected from a fixed matrix has been actively debated in several different disciplines. In this paper, a sampling approach based on the Monte Carlo method is presented as an efficient solver for such problems. Especially, the use of simulated annealing (SA), a metaheuristic optimization algorithm, for determining degrees of freedom (the number of used columns) by cross validation is focused on and tested. Test on a synthetic model indicates that our SA-based approach can find a nearly optimal solution for the approximation problem and, when combined with the CV framework, it can optimize the generalization ability. Its utility is also confirmed by application to a real-world supernova data set.
Recently, Markopoulos et al. [1], [2] presented an optimal algorithm that computes the L_1 maximum-projection principal component of any set of N real-valued data vectors of dimension D with complexity polynomial in N...
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ISBN:
(纸本)9781479928941
Recently, Markopoulos et al. [1], [2] presented an optimal algorithm that computes the L_1 maximum-projection principal component of any set of N real-valued data vectors of dimension D with complexity polynomial in N, O(N~D). Still, moderate to high values of the data dimension D and/or data record size N may render the optimal algorithm unsuitable for practical implementation due to its exponential in D complexity. In this paper, we present for the first time in the literature a fast greedy single-bit-flipping conditionally optimal iterative algorithm for the computation of the L_1 principal component with complexity O(N~3). Detailed numerical studies are carried out demonstrating the effectiveness of the developed algorithm with applications to the general field of data dimensionality reduction and direction-of-arrival estimation.
This paper deals with Elliptical Wishart distributions - which generalize the Wishart distribution - in the context of signal processing and machine learning. Two algorithms to compute the maximum likelihood estimator...
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Although many variants of stochastic gradient descent have been proposed for large-scale convex optimization, most of diem require projecting the solution at each iteration to ensure that the obtained solution stays w...
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ISBN:
(纸本)9781627480031
Although many variants of stochastic gradient descent have been proposed for large-scale convex optimization, most of diem require projecting the solution at each iteration to ensure that the obtained solution stays within the feasible domain. For complex domains (e.g., positive semidefinite cone), the projection step can be computationally expensive, making stochastic gradient descent unattractive for large-scale optimization problems. We address this limitation by developing novel stochastic optimization algorithms that do not need intermediate projections. Instead, only one projection at the last iteration is needed to obtain a feasible solution in the given domain. Our theoretical analysis shows diat with a high probability, the proposed algorithms achieve an O(1/T~(1/2)) convergence rate for general convex optimization, and an O (In T/T) rate for strongly convex optimization under mild conditions about the domain and the objective function.
The exponential growth of Internet-of-Things (IoT) devices not only brings convenience but also poses numerous challenging safety and security issues. IoT devices are distributed, highly heterogeneous, and more import...
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ISBN:
(数字)9781728146010
ISBN:
(纸本)9781728146027
The exponential growth of Internet-of-Things (IoT) devices not only brings convenience but also poses numerous challenging safety and security issues. IoT devices are distributed, highly heterogeneous, and more importantly, directly interact with the physical environment. In IoT systems, the bugs in device firmware, the defects in network protocols, and the design flaws in system configurations all may lead to catastrophic accidents, causing severe threats to people's lives and properties. The challenge gets even more escalated as the possible attacks may be chained together in a long sequence across multiple layers, rendering the current vulnerability analysis inapplicable. In this paper, we present ForeSee, a cross-layer formal framework to comprehensively unveil the vulnerabilities in IoT systems. ForeSee generates a novel attack graph that depicts all of the essential components in IoT, from low-level physical surroundings to high-level decision-making processes. The corresponding graph-based analysis then enables ForeSee to precisely capture potential attack paths. An optimization algorithm is further introduced to reduce the computational complexity of our analysis. The illustrative case studies show that our multilayer modeling can capture threats ignored by the previous approaches.
This paper investigates the mean-square stabilization problem for discrete-time networked control systems (NCSs). Different from most previous studies, we assume that transmission delay and packet dropout may occur si...
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ISBN:
(纸本)9781479978878
This paper investigates the mean-square stabilization problem for discrete-time networked control systems (NCSs). Different from most previous studies, we assume that transmission delay and packet dropout may occur simultaneously. The stabilization problem for such NCSs remains challenging because of the fundamental difficulty of stochastic control. The contributions of this paper are twofold. First, we present a necessary and sufficient condition for stabilizing the NCSs in terms of the unique positive solution to a specified algebraic equation. It is also shown that the NCS is stabilizable iff the generalized Lyapunov equation has a positive solution, which is in accordance with the classical result for a delay-free system. Second, we propose an optimization algorithm for computing the maximum packet dropout rate. The key technique adopted in this paper involves the Riccati-ZXL equation established in our earlier work.
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