针对化工过程运行状态在线评估的问题,提出多数据空间全潜结构映射(multi-space total projection to latent structures,Ms T-PLS)性能评估方法。该方法采用"离线建模,在线评估"的评估策略。首先对历史多数据输入空间进行全...针对化工过程运行状态在线评估的问题,提出多数据空间全潜结构映射(multi-space total projection to latent structures,Ms T-PLS)性能评估方法。该方法采用"离线建模,在线评估"的评估策略。首先对历史多数据输入空间进行全面分解,结合多数据空间基向量提取方法,剔除多数据输入空间中与质量变量无关信息的干扰。在与质量变量相关的多数据输入空间上,建立不同运行性能等级的离线数据网络分类模型,实现"离线建模"。"在线评估"阶段,以数据滑动时间窗为评估单元,将过程性能分为稳定和过渡性能等级,把在线数据与历史性能等级进行相似度匹配。利用过程变量相对贡献度,对性能变化起决定性影响的过程变量进行识别和贡献度分析,为系统性能劣化原因的识别提供了参考。最后,应用到乙烯裂解过程在线性能评估中,说明了本评估方法可以对系统进行准确的在线性能评估。展开更多
This study examines the relationship among independent boards of directors, board size, managerial share ownership （MSO）, and earnings quality. The study of these relationships is controlled by firm size based on a ...This study examines the relationship among independent boards of directors, board size, managerial share ownership （MSO）, and earnings quality. The study of these relationships is controlled by firm size based on a sample of 114 companies listed on the Tehran Stock Exchange （TSE） for the period from 2008 to 2010. The results demonstrate that there was an insignificant positive relationship among independent boards of directors, managerial ownership, and earnings quality. Subsequent analysis shows an insignificant negative relationship between board size and earnings quality. It also provides evidence of the negative relationship between firm size as a control variable and earnings quality. This can be attributed to the fact that large firms are claimed to be politically sensitive and thus have the incentive to lessen variances in changes in their reported earnings.展开更多
文摘针对化工过程运行状态在线评估的问题,提出多数据空间全潜结构映射(multi-space total projection to latent structures,Ms T-PLS)性能评估方法。该方法采用"离线建模,在线评估"的评估策略。首先对历史多数据输入空间进行全面分解,结合多数据空间基向量提取方法,剔除多数据输入空间中与质量变量无关信息的干扰。在与质量变量相关的多数据输入空间上,建立不同运行性能等级的离线数据网络分类模型,实现"离线建模"。"在线评估"阶段,以数据滑动时间窗为评估单元,将过程性能分为稳定和过渡性能等级,把在线数据与历史性能等级进行相似度匹配。利用过程变量相对贡献度,对性能变化起决定性影响的过程变量进行识别和贡献度分析,为系统性能劣化原因的识别提供了参考。最后,应用到乙烯裂解过程在线性能评估中,说明了本评估方法可以对系统进行准确的在线性能评估。
文摘This study examines the relationship among independent boards of directors, board size, managerial share ownership （MSO）, and earnings quality. The study of these relationships is controlled by firm size based on a sample of 114 companies listed on the Tehran Stock Exchange （TSE） for the period from 2008 to 2010. The results demonstrate that there was an insignificant positive relationship among independent boards of directors, managerial ownership, and earnings quality. Subsequent analysis shows an insignificant negative relationship between board size and earnings quality. It also provides evidence of the negative relationship between firm size as a control variable and earnings quality. This can be attributed to the fact that large firms are claimed to be politically sensitive and thus have the incentive to lessen variances in changes in their reported earnings.
