基于AT90CAN128的CAN总线数据采集终端设计

CAN总线在工业数据采集系统中应用越来越广泛,本文设计了基于AT90CAN128的数据采集系统,采用单片机AT90CAN128作为监控主机,及时将底层智能节点采集的数据通过CAN总线传送到上位机,实现实时监控。     

How schools and students respond to school improvement programs: The case of Brazil's PDE

This study uses rich empirical data from Brazil to assess how a government program (PDE) that decentralizes school management decisions changes what goes on in schools and how these changes affect student outcomes. It appears that the PDE resulted in some improvements in management and learning materials, but little change in other areas including evaluation and community relations. However, we find no evidence that schools’ participation in the PDE improved student achievement. The results for grade passing are stronger. Students in PDE schools saw greater increases in grade passing rates than students in non-PDE schools during the period of our study. We also estimate a positive relationship between PDE spending and student gains for those schools in the program, especially for spending on teaching and learning materials and furniture. We find no benefit of electronics spending or spending on teacher training, two of the three largest areas of school investment.