Engineering with Computers - The indirect and accurate determination of blast-induced rock movement has important significance in the reduction of ore loss and dilution and in the protection of... 相似文献
时间抽象是分层强化学习中的重要研究方向,而子目标是时间抽象形成的核心元素.目前,大部分分层强化学习需要人工给出子目标或设定子目标数量.然而,在很多情况下,这不仅需要大量的人工干预,而且所作设定未必适合对应场景,在动态环境未知的指导下,这一问题尤为突出.针对此,提出基于优化子目标数的Option-Critic算法(Option-Critic algorithm based on Sub-goal Quantity Optimization,OC-SQO),增加了智能体对环境的探索部分,通过与环境的简单交互,得到适用于应用场景的初始子目标数量估值,并在此基础上识别子目标,然后利用通过策略梯度生成对应的抽象,使用初态、内部策略和终止函数构成的三元组表示,以此进行训练,根据交互得到的抽象改变当前状态,不断迭代优化.OC-SQO算法可以在任意状态下开始执行,不要求预先指定子目标和参数,在执行过程中使用策略梯度生成内部策略、抽象间策略和终止函数,不需要提供内部奖赏信号,也无需获取子目标的情况,尽可能地减少了人工干预.实验验证了算法的有效性. 相似文献
In the fed-batch cultivation of Saccharomyces cerevisiae, excessive glucose addition leads to increased ethanol accumulation, which will reduce the efficiency of glucose utilization and inhibit product synthesis. Insufficient glucose addition limits cell growth. To properly regulate glucose feed, a different evolution algorithm based on self-adaptive control strategy was proposed, consisting of three modules (PID, system identification and parameter optimization). Performance of the proposed and conventional PID controllers was validated and compared in simulated and experimental cultivations. In the simulation, cultivation with the self-adaptive control strategy had a more stable glucose feed rate and concentration, more stable ethanol concentration around the set-point (1.0 g•L-1), and final biomass concentration of 34.5 g-DCW•L-1, 29.2% higher than that with a conventional PID control strategy. In the experiment, the cultivation with the self-adaptive control strategy also had more stable glucose and ethanol concentrations, as well as a final biomass concentration that was 37.4% higher than that using the conventional strategy. 相似文献
Journal of Mathematical Imaging and Vision - Different from the traditional watermarking schemes, zero-watermarking schemes are lossless embedding methods, which are applicable to be used in... 相似文献
3D printing offers great potential for developing complex flexure mechanisms. Recently, thickness-correction factors (TCFs) were introduced to correct the thickness and stiffness deviations of powder-based metal 3D printed flexure hinges during design and analysis. However, the reasons for the different TCFs obtained in each study are not clear, resulting in a limited value of these TCFs for future design and fabrication. Herein, the influence of the porous layer of 3D printed flexure hinges on the hinge thickness is investigated. Samples of parallelogram flexure mechanisms (PFMs) were 3D printed using selective laser melting (SLM) and 316L stainless steel powder. A 3D manufacturing error analysis was completed for each PFM sample via 3D scanning, surface roughness measurement and morphological observation. The thickness of the porous layer of the flexure hinge was independent of the designed hinge thickness and remained close to the average powder particle diameter. The effective hinge thickness could be estimated by subtracting twice the value of the porous layer thickness from the designed value. Guidelines based on finite element analysis and stiffness experiments are proposed. The limitations of the presented method for evaluating the effective hinge thickness of flexure hinges 3D printed via SLM are also discussed.