排序方式: 共有22条查询结果,搜索用时 15 毫秒
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在经典的双边全变差(BTV)超分辨率重建中,加权系数和正则化参数的恒定性导致重建结果边缘保持能力受限。为此,提出了一种自适应约束的BTV正则化先验模型。算法首先定义了图像的局部邻域残差均值以区分当前像素属于平坦区域还是边缘区域;然后针对加权系数的不变性导致边缘削弱的问题,利用边缘方向和垂直边缘方向扩散性的不同,设计自适应权重矩阵;最后根据代价函数的极值问题推导出迭代公式,从而进行图像的超分辨率重建,重建过程中采用自适应的方法确定正则化参数,以便求得代价函数的全局最优解,提高了算法的鲁棒性。实验结果表明:与双三次线性插值法和经典BTV算法相比,该算法取得了更好的视觉效果和更高的峰值信噪比,更多地保留了图像的边缘细节信息。 相似文献
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汽车产业外部性的存在,不仅关系到汽车产业的可持续发展,而且也对宏观经济产生了深刻的影响。汽车产业与经济、社会、环境协调发展的问题,已经远远超出了汽车投资和生产层面,客观上要求政府采取适当的政策措施来妥善解决汽车产业发展带来的外部环境问题。文章运用外部性理论和 相似文献
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Robert B. Gramacy 《Revue internationale de statistique》2020,88(2):326-329
I thoroughly enjoyed reading the article by Bhadra et. al. (2020) and convey my congratulations to the authors for providing a comprehensive and coherent review of horseshoe-based regularization approaches for machine learning models. I am thankful to the editors for providing this opportunity to write a discussion on this useful article, which I expect will turn out to be a good guide in the future for statisticians and practitioners alike. It is quite amazing to see the rapid progress and the magnitude of work advancing the horseshoe regularization approach since the seminal paper by Carvalho et al. (2010). The current review article is a testimony for this. While I have been primarily working with continuous spike and slab priors for high-dimensional Bayesian modeling, I have been following the literature on horseshoe regularization with a keen interest. For my comments on this article, I will focus on some comparisons between these two approaches particularly in terms of model building and methodology and some computational considerations. I would like to first provide some comments on performing valid inference based on the horsheshoe prior framework. 相似文献
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We approach the continuous‐time mean–variance portfolio selection with reinforcement learning (RL). The problem is to achieve the best trade‐off between exploration and exploitation, and is formulated as an entropy‐regularized, relaxed stochastic control problem. We prove that the optimal feedback policy for this problem must be Gaussian, with time‐decaying variance. We then prove a policy improvement theorem, based on which we devise an implementable RL algorithm. We find that our algorithm and its variant outperform both traditional and deep neural network based algorithms in our simulation and empirical studies. 相似文献
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通过添加一个正则化因子α,使时间序列AR(n)模型的最小二乘估计(X′X)-1X′Y变为(X′X+αI)-1X′Y,改善了时间序列分析模型中信息矩阵的病态程度,避免了时间序列分析模型产生不适定;经济统计数据分析表明,新的正则化时间序列分析模型在一定程度上起到了稳定所求参数的作用。 相似文献
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