In this paper, we analyze the convergence rate of the Heavy-ball algorithm applied to optimize a class of continuously differentiable functions. The analysis is performed with the Heavy-ball tuned to achieve the best ...
详细信息
ISBN:
(纸本)9781538679012;9781538679265
In this paper, we analyze the convergence rate of the Heavy-ball algorithm applied to optimize a class of continuously differentiable functions. The analysis is performed with the Heavy-ball tuned to achieve the best convergence rate on the sub-class of quadratic functions. We review recent work to characterize convergence rate upper bounds for optimization algorithms using integral quadratic constraints (IQC). This yields a linear matrix inequality (LMI) condition which is typically solved numerically to obtain convergence rate bounds. We construct an analytical solution for this LMI condition using a specific "weighted off-by-one" IQC. We also construct a specific objective function such that the Heavy-ball algorithm enters a limit cycle. These results demonstrate that IQC condition is tight for the analysis of the tuned Heavy-ball, i.e. it yields the exact condition ratio that separates global convergence from non-global convergence for the algorithm.
The objective of this paper is to provide some initial results on the application of control tools to the problem treatment design. Human behavior and reaction to treatment is complex and dependent on many unmeasurabl...
详细信息
ISBN:
(纸本)9781467357159
The objective of this paper is to provide some initial results on the application of control tools to the problem treatment design. Human behavior and reaction to treatment is complex and dependent on many unmeasurable external stimuli. Therefore, to the best of our knowledge, it cannot be described by simple models. Hence, one of the main messages in this paper is that, to design a treatment (controller) one cannot rely on exact models. More precisely, to be able to design effective treatments, we propose to use "simple" uncertain affine models whose response "covers" the most probable subject responses. So, we propose a simple model that contains two different types of uncertainties: one aimed at uncertainty of the dynamics and another aimed at approximating external perturbations that patients face in their daily life. With this model at hand, we design a robust model predictive controller, where one relies on the special structure of the uncertainty to develop efficient optimization algorithms.
Air pollution in the atmosphere derives from complex non-linear relationships, involving anthropogenic and biogenic precursor emissions. Due to this complexity, Integrated Assessment Modelling systems (IAMs) can be us...
详细信息
ISBN:
(纸本)9781467357159
Air pollution in the atmosphere derives from complex non-linear relationships, involving anthropogenic and biogenic precursor emissions. Due to this complexity, Integrated Assessment Modelling systems (IAMs) can be used, to help Environmental Authorities to control air quality reducing human and ecosystems pollution exposure effects in a cost efficient way. In this context, the literature suggests control modeling systems solving multi-objective optimization problems. Such approach requires descriptive models linking the control variables to the objectives. As they are assessed thousands and thousands of times by the optimization algorithms, they have to be on one hand no time consuming and on the other hand enough robust. It follows that one of the main aspects to be taken into account assessing the control policies is the impact of uncertainties, in the descriptive models itself and in the optimization control problem results. In this work the application of the general probabilistic framework (GPF) for uncertainty and sensitivity analysis has been applied to assess the sensitivity of the descriptive models in a PM10 exposure control problem over Northern Italy, an area often characterized by high pollution levels.
We present a method for calibrating the Ensemble of Exemplar SVMs model. Unlike the standard approach, which calibrates each SVM independently, our method optimizes their joint performance as an ensemble. We formulate...
详细信息
ISBN:
(纸本)9781467369657
We present a method for calibrating the Ensemble of Exemplar SVMs model. Unlike the standard approach, which calibrates each SVM independently, our method optimizes their joint performance as an ensemble. We formulate joint calibration as a constrained optimization problem and devise an efficient optimization algorithm to find its global optimum. The algorithm dynamically discards parts of the solution space that cannot contain the optimum early on, making the optimization computationally feasible. We experiment with EE-SVM trained on state-of-the-art CNN descriptors. Results on the ILSVRC 2014 and PASCAL VOC 2007 datasets show that (i) our joint calibration procedure outperforms independent calibration on the task of classifying windows as belonging to an object class or not;and (ii) this improved window classifier leads to better performance on the object detection task.
Orthogonal binary sequences play an important role in Multiple-input multiple-output (MIMO) radar. However, mainly due to mathematical difficulties, the synthesis problem of multiple binary sequences with low auto and...
详细信息
ISBN:
(纸本)9781510822023
Orthogonal binary sequences play an important role in Multiple-input multiple-output (MIMO) radar. However, mainly due to mathematical difficulties, the synthesis problem of multiple binary sequences with low auto and cross correlation sidelobes is still an open problem. In this paper, mismatched filter, which basically aims at reducing the sidelobe levels at the pulse compression output, is exploited and multiple binary sequences and mismatched filters are optimized by joint synthesis algorithms (JSA), based on an alternating direction method. JSA for minimizing the integrated sidelobe level (ISL) and peak sidelobe level (PSL) metrics are proposed, and the corresponding computation complexities are analyzed. Simulation results show the effectiveness of our proposed algorithms.
Nowadays, the total power consumed by data centers is increasing more and more. In particular, the power consumed by data center facilities accounts for about half of total input power. In this paper, a hierarchical c...
详细信息
ISBN:
(纸本)9781509045839
Nowadays, the total power consumed by data centers is increasing more and more. In particular, the power consumed by data center facilities accounts for about half of total input power. In this paper, a hierarchical control structure is proposed for efficient management of an indirect adiabatic cooling system, which utilizes fresh air. Data center cooling needs can be met with various combinations of modes of operation that can be set by a supervisor to maximize the overall operating efficiency. Here, the best combination is determined by solving an energy based optimization problem, which is faced by means of a nature-inspired optimization algorithm. The effectiveness of the proposed control system is evaluated by resorting to a simulation environment, that is developed in Matlab/Simulink and where the performance of the computers room air conditioning unit is described.
An ultra-thin reconfigurable absorber concept based on metasurfaces is presented. First, an artificial magnetic conducting (AMC) metasurface absorber is examined that incorporates lumped resistors along with variable ...
详细信息
ISBN:
(纸本)9781467321877
An ultra-thin reconfigurable absorber concept based on metasurfaces is presented. First, an artificial magnetic conducting (AMC) metasurface absorber is examined that incorporates lumped resistors along with variable lumped capacitors, which allow its frequency response to be tuned. The parasitic effects introduced by the lumped capacitors are compensated by adding resistors whose values are determined using an optimization algorithm known as the covariance matrix adaptation evolutionary strategy (CMA-ES). Second, the feasibility of achieving broadband absorption using frequency selective surfaces (FSSs) comprised of square loops is examined. Such a structure offers greater tunability, and thus wideband absorption can be achieved. First, an absorber that utilizes an FSS comprised by two square loops along with lumped resistors is studied and its wideband absorption properties are demonstrated. Second, an absorber that incorporates a resistive frequency selective surface comprised by four square loops and a center patch is presented.
In this paper, we consider the runtime monitoring of norms with imperfect monitors. A monitor is imperfect for a norm if it has insufficient observational capabilities to determine if a given execution trace of a mult...
详细信息
ISBN:
(纸本)9781634391313
In this paper, we consider the runtime monitoring of norms with imperfect monitors. A monitor is imperfect for a norm if it has insufficient observational capabilities to determine if a given execution trace of a multi-agent system complies with or violates the norm. One approach to the problem of imperfect monitors is to enhance the observational capabilities of the normative organisation. However this may be costly or in some cases impossible. Instead we show how to synthesise an approximation of an 'ideal' norm that can be perfectly monitored given a monitor, and which is optimal in the sense that any other approximation would fail to detect at least as many violations of the ideal norm. We give a logical analysis of (im)perfect monitors. We state the computational complexity of the norm approximation problem, and give an optimal algorithm for generating optimal approximations of norms given a monitor.
Having in mind various implementations of methods for generating network topology [1], [2], [3], there is also a need for a wider mechanism determining receiving nodes in a network by geographical positioning, or one ...
详细信息
Having in mind various implementations of methods for generating network topology [1], [2], [3], there is also a need for a wider mechanism determining receiving nodes in a network by geographical positioning, or one that would be related to link and node parameters. This will allow us to answer the question whether the way receiving nodes are distributed has any influence on the quality of multicast trees constructed by algorithms. The paper proposes methods that arrange group members in packet-switched networks. In the research we discuss the influence of the group arrangement method on the total cost of tree and the average cost of path in a tree for unconstrained routing algorithms for multicast connections. The methods for the receiving nodes distribution in the network have not been hitherto addressed and analyzed in literature.
暂无评论