Almost three-quarters of the underling information in the light wave field is embodied in the phase. However, the early optical detectors can only record the intensity or amplitude of the light wave field and cannot d...
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ISBN:
(纸本)9781728128177
Almost three-quarters of the underling information in the light wave field is embodied in the phase. However, the early optical detectors can only record the intensity or amplitude of the light wave field and cannot directly extract the phase information of the light wave field. Therefore, it is necessary to use the measured amplitude or strength to reconstruct the phase information of the object, this problem is denoted phase retrieval. Phase retrieval is a matter of cardinal significance in signal processing and machine learning. The phase retrieval by convex optimization algorithm is ideal but the computational complexity is high. In 2015, Candès proposed a very effective non-convex optimization algorithm-Wirtinger flow algorithm which used spectral initialization to get a better initial value and then gradient iteration to get a promised recovery effect. Subsequently, in line with the idea, a large number of variants are devised, such as: Wirtinger flow(WF), Truncated Wirtinger Flow (TWF), Truncated Amplitude Flow (TAF), Reshaped Wirtinger Flow (RWF), Incremental Truncated Wirtinger Flow (ITWF), Incremental Reshaped Wirtinger Flow (IRWF), Robust Wirtinger Flow (Robust-WF), Sparse Wirtinger Flow (SWF), Median-TWF, Median-RWF, Generalized Wirtinger Flow (GWF), Accelerated Wirtinger Flow (AWF), Thresholded Wirtinger Flow Revisited (THWFR), Thresholded Wirtinger Flow (THWF), Reweighted Wirtinger Flow (REWF), Wirtinger Flow Method With Optimal Stepsize (WFOS), Stochastic Truncated Wirtinger Flow Algorithm (STWF), Stochastic Truncated Amplitude Flow (STAF), Reweighted Amplitude Flow (RAF), Compressive Reweighted Amplitude Flow (CRAF), SPARse Truncated Amplitude flow (SPARTA) and Sparse Wirtinger Flow Algorithm with Optimal Stepsize (SWFOS), etc. This paper analyzes and summarizes these algorithms according to their characteristics such as: initialization method, step size, iteration times, sample complexity, computational complexity, etc., so that readers can intuitiv
An easy and effective strategy for the reconfiguration of time-modulated linear arrays in presence of failures is proposed. Starting from the knowledge of the failed elements, the pulse sequence controlling the set of...
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ISBN:
(纸本)9781467353168
An easy and effective strategy for the reconfiguration of time-modulated linear arrays in presence of failures is proposed. Starting from the knowledge of the failed elements, the pulse sequence controlling the set of radio-frequency (RF) switches modulating the static excitations of the correct elements is properly reconfigured to obtain a radiation pattern at the antenna working frequency close as much as possible to the one generated by the array without failures. A suitable optimization algorithm based on the Particle Swarm optimization (PSO) is used to define the degrees of freedom describing the time-modulation sequence. A preliminary result is reported to show the behavior of the proposed method.
As cloud computing grows rapidly and virtualization techniques become more widely-used, it is critical and important to allocate limited resources to various applications on demand for the cloud service environments. ...
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ISBN:
(纸本)9781424465392;9781424465422
As cloud computing grows rapidly and virtualization techniques become more widely-used, it is critical and important to allocate limited resources to various applications on demand for the cloud service environments. In this article, we propose an adaptive resource management approach considering multi-resource transformation to fully utilize extra resource capacity. The definition of the optimization problem concerning resource co-allocation is presented and then an optimization algorithm is developed and described, which carries out stochastic and directional search step by step to jointly schedule different resources. The evaluation results of simulation experiments demonstrate that by using the resource co-allocation approach we designed, the performance of different applications deployed in the cloud environment could be guaranteed subject to the QoS (Quality of Service) specification, despite of the significant fluctuation of workloads.
Tensor networks are a tool first employed in the context of many-body quantum physics that now have a wide range of uses across the computational sciences, from numerical methods to machine learning. Methods integrati...
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We provide a new analysis framework for the adversarial multi-armed bandit problem. Using the notion of convex smoothing, we define a novel family of algorithms with minimax optimal regret guarantees. First, we show t...
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ISBN:
(纸本)9781510825024
We provide a new analysis framework for the adversarial multi-armed bandit problem. Using the notion of convex smoothing, we define a novel family of algorithms with minimax optimal regret guarantees. First, we show that regular-ization via the Tsallis entropy, which includes EXP3 as a special case, matches the O(NT~(1/2)) minimax regret with a smaller constant factor. Second, we show that a wide class of perturbation methods achieve a near-optimal regret as low as O(NT log N~(1/2)), as long as the perturbation distribution has a bounded hazard function. For example, the Gumbel, Weibull, Frechet, Pareto, and Gamma distributions all satisfy this key property and lead to near-optimal algorithms.
Petri Nets are powerful simulation tool for process industries,based on theories of Petri Nets,this paper structured the framework of process *** and qualitative relationships between production and energy consumption...
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Petri Nets are powerful simulation tool for process industries,based on theories of Petri Nets,this paper structured the framework of process *** and qualitative relationships between production and energy consumption system and Information system are *** to production and energy consumption model,enterprises integrated Petri Nets framework are divided into linear and nonlinear *** to parameter of scheduling or optimization time,the integrated model furthermore were assigned as constraints depend on time and in-depend on time,and energy saving production optimization algorithms library were ***,the approach is proved by an engineering example.
In this paper, we propose some accelerated methods for solving optimization problems under the condition of relatively smooth and relatively Lipschitz continuous functions with an inexact oracle. We consider the probl...
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In providing simultaneous information on expression profiles for thousands of genes, microarray technologies have, in recent years, been largely used to investigate mechanisms of gene expression. Clustering and classi...
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ISBN:
(纸本)9781457702150
In providing simultaneous information on expression profiles for thousands of genes, microarray technologies have, in recent years, been largely used to investigate mechanisms of gene expression. Clustering and classification of such data can, indeed, highlight patterns and provide insight on biological processes. A common approach is to consider genes and samples of microarray datasets as nodes in a bipartite graphs, where edges are weighted e.g. based on the expression levels. In this paper, using a previously-evaluated weighting scheme, we focus on search algorithms and evaluate, in the context of biclustering, several variations of Genetic algorithms. We also introduce a new heuristic "Propagate", which consists in recursively evaluating neighbour solutions with one more or one less active conditions. The results obtained on three well-known datasets show that, for a given weighting scheme, optimal or near-optimal solutions can be identified.
We propose a distributed, anytime optimization algorithm to maximize the thermal comfort of building occupants. We consider the building as a set of areas consisting of zones, which are coupled by the capacity of the ...
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ISBN:
(纸本)9781457710957
We propose a distributed, anytime optimization algorithm to maximize the thermal comfort of building occupants. We consider the building as a set of areas consisting of zones, which are coupled by the capacity of the HVAC equipment as well as the energy and mass balance relations that govern the building dynamics. The resulting non-convex, large-dimensional, constrained optimization formulation is decomposed into area-level subproblems that are solved by distributed agents. At each timestep, the agents cooperate to converge to an equilibrium solution that determines the optimal values of the building operational variables, such as temperature and rate of air flow, that maximizes the total comfort. Our experimental results show that the distributed algorithm (i) is more scalable than the centralized optimization algorithm;(ii) produces a locally optimal solution that is comparable to that resulting from the centralized approach;and (iii) yields a feasible solution even if pre-empted before equilibrium is attained.
The paper considers optimal pulse-width modulation of a single phase voltage source inverter with LC filter. The approach is based on model predictive control which requires a non-convex optimization problem to be sol...
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ISBN:
(纸本)9781467371520
The paper considers optimal pulse-width modulation of a single phase voltage source inverter with LC filter. The approach is based on model predictive control which requires a non-convex optimization problem to be solved in real-time. A new optimization algorithm for solving the problem is presented. The proposed algorithm utilizes an invariance property of the LC filter to recast the non-convex optimization problem as a convex quadratic problem. The novel algorithm has significant advantages compared to previously applied methods since it has lower complexity and is, under certain assumptions, guaranteed to find the global optimum.
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