在许多机器学习应用中,需要分析的数据可能由对称正定矩阵构成,而经典的欧氏机器学习算法处理这种数据的性能较差。针对此问题,提出一种新的基于对数欧氏度量学习的概率黎曼空间量化方法。该方法将对称正定矩阵看做对数欧氏度量下黎曼...在许多机器学习应用中,需要分析的数据可能由对称正定矩阵构成,而经典的欧氏机器学习算法处理这种数据的性能较差。针对此问题,提出一种新的基于对数欧氏度量学习的概率黎曼空间量化方法。该方法将对称正定矩阵看做对数欧氏度量下黎曼流形上的点,采用对数欧氏度量学习距离函数将概率学习矢量量化方法从欧氏空间推广到对称正定黎曼空间。在BCI IV 2a脑电数据集上,该方法相较于概率学习矢量量化方法识别正确率提升20%,高于竞赛第一名;并且计算速度快,模型训练及测试时间分别为基于仿射不变度量的同类型算法的1%和10%。在BCI III IIIa和图像数据集ETH-80上也取得了较好的结果。展开更多
The powders of the AA 7075-ZRO2 were mixed by mechanical milling, but it was found that the system presents a few disadvantages when processed by conventional sintering and hot extrusion, since intermetallic phases be...The powders of the AA 7075-ZRO2 were mixed by mechanical milling, but it was found that the system presents a few disadvantages when processed by conventional sintering and hot extrusion, since intermetallic phases between ZrO2 particles and alloying elements were formed. Equal channel angular pressing （ECAP） processing was proposed as an alternative method to consolidate the composite where there is no intermetallic formation. The analysis of the ECAP process showed that the intermediate temperature （220℃） produced a higher consolidation level than conventional sintering and hot extrusion （400 and 500℃, respectively）. This fact was supported by relative density analysis. In the case of the sintered and hot-extruded sample, the relative density exhibited a value of 0.95, while ECAP sample showed a value of 0.98. Hardness values show that microstructural refinement obtained during mechanical milling was preserved during ECAP processing even when it was carded out at 220℃.展开更多
文摘在许多机器学习应用中,需要分析的数据可能由对称正定矩阵构成,而经典的欧氏机器学习算法处理这种数据的性能较差。针对此问题,提出一种新的基于对数欧氏度量学习的概率黎曼空间量化方法。该方法将对称正定矩阵看做对数欧氏度量下黎曼流形上的点,采用对数欧氏度量学习距离函数将概率学习矢量量化方法从欧氏空间推广到对称正定黎曼空间。在BCI IV 2a脑电数据集上,该方法相较于概率学习矢量量化方法识别正确率提升20%,高于竞赛第一名;并且计算速度快,模型训练及测试时间分别为基于仿射不变度量的同类型算法的1%和10%。在BCI III IIIa和图像数据集ETH-80上也取得了较好的结果。
基金supported by Universidad Autónoma de San Luis Potosi, Centro de Investigación en Materiales Avanzados Unidad Chihuahua and Universitat Politècnica de CatalunyaFinancial support by CONACYT is appreciatedfinancial support from FAI-UASLP under the project CI5-FAI-04-45.45
文摘The powders of the AA 7075-ZRO2 were mixed by mechanical milling, but it was found that the system presents a few disadvantages when processed by conventional sintering and hot extrusion, since intermetallic phases between ZrO2 particles and alloying elements were formed. Equal channel angular pressing （ECAP） processing was proposed as an alternative method to consolidate the composite where there is no intermetallic formation. The analysis of the ECAP process showed that the intermediate temperature （220℃） produced a higher consolidation level than conventional sintering and hot extrusion （400 and 500℃, respectively）. This fact was supported by relative density analysis. In the case of the sintered and hot-extruded sample, the relative density exhibited a value of 0.95, while ECAP sample showed a value of 0.98. Hardness values show that microstructural refinement obtained during mechanical milling was preserved during ECAP processing even when it was carded out at 220℃.
