Exploration is a major challenge in reinforcement learning, especially for high-dimensional domains that require function approximation. We propose exploration objectives-policy optimization objectives that enable dow...
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Exploration is a major challenge in reinforcement learning, especially for high-dimensional domains that require function approximation. We propose exploration objectives-policy optimization objectives that enable downstream maximization of any reward function-as a conceptual framework to systematize the study of exploration. We introduce a new objective, L-1-Coverage, which generalizes previous exploration schemes and supports three fundamental desiderata: 1. Intrinsic complexity control. L-1-Coverage is associated with a structural parameter, L-1-Coverability, which reflects the intrinsic statistical difficulty of the underlying MDP, subsuming Block and Low-Rank MDPs. 2. Efficient planning. For a known MDP, optimizing L-1-Coverage efficiently reduces to standard policy optimization, allowing flexible integration with off-the-shelf methods such as policy gradient and Q-learning approaches. 3. Efficient exploration. L-1-Coverage enables the first computationally efficient model-based and model-free algorithms for online (reward-free or reward-driven) reinforcement learning in MDPs with low coverability. Empirically, we find that L-1-Coverage effectively drives off-the-shelf policy optimization algorithms to explore the state space.
The present paper addresses the multi-objective aerodynamic shape optimization of the two-dimensional LS-89 turbine cascade. The objective is to minimize the entropy generation at subsonic and transonic flow condition...
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ISBN:
(纸本)9780791886120
The present paper addresses the multi-objective aerodynamic shape optimization of the two-dimensional LS-89 turbine cascade. The objective is to minimize the entropy generation at subsonic and transonic flow conditions while maintaining the same flow turning. Nineteen design variables are used to parametrize the geometry. The optimization problem is used to compare two major classes of optimization algorithms and at the same time deduce if this problem has multiple local solutions or one global optimum. A first optimization strategy uses a gradient-based Sequential Quadratic Programming algorithm. This SQP algorithm allows to directly handle the non-linear constraints during the optimization process. An adjoint solver is used for computing the sensitivities of the flow quantities with respect to the design variables, such that the additional gradient computational cost is nearly independent of the number of design variables. In addition, the same optimization problem is performed with a gradient-free - metamodel assisted - evolutionary algorithm. A comparison of the two Pareto-fronts obtained with both methods shows that the gradient-based approach allows to find the same optimum at a reduced computational cost. Moreover, the results suggest that the considered optimization problem is uni-modal. In other terms, it is characterized by a single optimal solution.
In thermal analysis modeling, the finite element method (FEM) is commonly used;however, it incurs high computational costs and complicates the global optimization of thermal parameters. To address these challenges, de...
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In thermal analysis modeling, the finite element method (FEM) is commonly used;however, it incurs high computational costs and complicates the global optimization of thermal parameters. To address these challenges, developing simplified surrogate models is crucial for enhancing analysis efficiency. Yet, constructing such models demands exceptional predictive accuracy, making conventional parameter adjustment methods inadequate for design needs. This paper introduces a novel Residual connection Neural Network model, called Res-NN, designed to approximate the CMOS finite element model. By employing residual connections, the Res-NN model significantly reduces fitting errors between networks, achieving a predictive accuracy of 94.6 %, which is 6.6 % higher than that of comparable Multi-Layer Perceptron (MLP) models. Moreover, Res-NN is over 100 times faster than traditional FEM in prediction speed, effectively circumventing the difficulties associated with parameter adjustments. To optimize the temperature fluctuations of the CMOS model, we utilized the Res-NN model as an iterative object within an optimization algorithm. Through experimental comparisons, we identified the PSO algorithm as the most effective option. The PSO optimization results demonstrated a chip temperature difference of 0.045 degrees C, with a simulation error of only 0.0649 degrees C, meeting design specifications and achieving a 61.7 % reduction in temperature variance compared to traditional thermal design method. This validates the superiority of the entire optimization process.
The modern times have led to the adoption of distinctive meta-heuristic procedures for solving distinct class of optimization-problems. The meta-heuristics procedures have benefit above conventional algorithms because...
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The traditional clustering algorithms mostly use simple one-dimensional distance measurement and overall optimization strategy for classification, one-dimensional measurement method can identify similarity matrix, but...
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In the rapidly evolving world of wireless cellular network, optimizing key parameters like data throughput and latency is of critical importance for ensuring high quality communication services. The proposed presents ...
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This paper presents a newly improved version of the Whale optimization Algorithm based on quantum theory by optimizing the Artificial Neural Network for the ground response approximation problems in short buildings. B...
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This paper presents a newly improved version of the Whale optimization Algorithm based on quantum theory by optimizing the Artificial Neural Network for the ground response approximation problems in short buildings. Based on the literature, Artificial Neural Network does not provide a proper response of ground surface prediction in seismic load applications. Hence, the main idea of this study is to assess the utilization of the whale optimization algorithm for calculating the columns' horizontal deflection in the short structure under notable considered seismic loading. The input database utilized in this paper is the Chi-Chi earthquake that is occurred in 1999 in Taiwan. To provide the train and test databases for the artificial neural network algorithm and whale optimization algorithm, Finite Element models are used. The inputs contain the Chi-Chi earthquake's dynamic time, soil elastic modulus, dilation angle, Poisson's ratio, unit weight, friction angle, bending stiffness and axial stiffness. Also the columns' horizontal deflection in their highest level is considered as the output. The results showed the higher reliability of the proposed WOA in calculating the ground response and the column's horizontal deflection in short buildings subjected to the earthquake loading. (C) 2021 The Authors. Published by Elsevier Ltd.
For multi-revolution rendezvous near elliptical reference orbit, the singularities of the semi-revolution and complete-revolution rendezvous are eliminated. The semi-revolution and complete-revolution rendezvous schem...
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A majority of recent developments in neural architecture search (NAS) have been aimed at decreasing the computational cost of various techniques without affecting their final performance. Towards this goal, several lo...
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A majority of recent developments in neural architecture search (NAS) have been aimed at decreasing the computational cost of various techniques without affecting their final performance. Towards this goal, several low-fidelity and performance prediction methods have been considered, including those that train only on subsets of the training data. In this work, we present an adaptive subset selection approach to NAS and present it as complementary to state-of-the-art NAS approaches. We uncover a natural connection between one-shot NAS algorithms and adaptive subset selection and devise an algorithm that makes use of state-of-the-art techniques from both areas. We use these techniques to substantially reduce the runtime of DARTS-PT (a leading one-shot NAS algorithm) with minimal sacrifice to accuracy and to give reasonable runtime reductions for BOHB and DEHB (leading multi-fidelity optimization algorithms) as well. In experiments, we find architectures on CIFAR-10 that give 5% increase in performance over DARTS-PT while reducing the time required by more than a factor of 8. Our results are consistent across multiple datasets, and towards full reproducibility, we release all our code at https://***/pcvishak/SubsetSelection_NAS.
In recent days, credit card fraud has emerged as a significant challenge for researchers in the field of detection and prevention. Tackling this challenge holds substantial benefits for both public and private organiz...
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In recent days, credit card fraud has emerged as a significant challenge for researchers in the field of detection and prevention. Tackling this challenge holds substantial benefits for both public and private organizations, as it directly impacts economic statistics. Our proposed model introduces crucial advancements to address this issue in real-time scenarios. To achieve this, we harnessed the power of Deep Convolutional Neural Networks (DeepConvNet) in conjunction with various optimization techniques. optimization algorithms encompass a group of mathematical and computational techniques employed to discover the most suitable solution or set of solutions for a given problem. The primary goal of these algorithms is to optimize, either by maximizing or minimizing, an objective function while ensuring compliance with specific constraints. In this research work, we provide a comparison of highly effective and validated optimization techniques: Stochastic Gradient Descent (Sgd), Adaptive Gradient (Adagrad), Adaptive Moment Estimation (Adam), and Root Mean Squared Propagation (Rmsprop). These optimization algorithms are applied to the Deep Convolutional Neural Network (DeepConvNet) in the subject of our specific problem statement, which involves credit card fraud detection (CCFD). After careful consideration of the problem’s nature, objective function characteristics, and computational aspects, we fnd that all four algorithms are suitable for our CCFD task. However, based on experimental results, it is evident that Rmsprop outperforms others, leading to a remarkable 99.93% in accuracy.
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