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建立《科学》课程质性评价网
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作者 王景 《科学教育》 2002年第6期32-33,共2页
既要淡化科学的选拔功能,又要确保科学教学质量,促进全体学生科学素养提高,是新课程《科学》教学中的一个难题。在新课程《科学》教学中,我采取课内课外相结合,自评他评相结合,学校、社区相结合,学科学与用科学相结合,建立《科学》质性... 既要淡化科学的选拔功能,又要确保科学教学质量,促进全体学生科学素养提高,是新课程《科学》教学中的一个难题。在新课程《科学》教学中,我采取课内课外相结合,自评他评相结合,学校、社区相结合,学科学与用科学相结合,建立《科学》质性评价网,以全面提高学生的科学素养。1 建立三种成长记录本。 展开更多
关键词 《科学》课程 质性评价网 中学 教学评价
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Modeling and performance evaluation of QoS-aware job scheduling of computational grids
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作者 单志广 林闯 《Journal of Southeast University(English Edition)》 EI CAS 2007年第3期425-430,共6页
To achieve high quality of service (QoS) on computational grids, the QoS-aware job scheduling is investigated for a hierarchical decentralized grid architecture that consists of multilevel schedulers. An integrated ... To achieve high quality of service (QoS) on computational grids, the QoS-aware job scheduling is investigated for a hierarchical decentralized grid architecture that consists of multilevel schedulers. An integrated QoS-aware job dispatching policy is proposed, which correlates priorities of incoming jobs used for job selecting at the local scheduler of the grid node with the job dispatching policies at the global scheduler for computational grids. The stochastic high-level Petri net (SHLPN) model of a two-level hierarchy computational grid architecture is presented, and a model refinement is made to reduce the complexity of the model solution. A performance analysis technique based on the SHLPN is proposed to investigate the QoS-aware job scheduling policy. Numerical results show that the QoS-aware job dispatching policy outperforms the QoS-unaware job dispatching policy in balancing the high-priority jobs, and thus enables priority-based QoS. 展开更多
关键词 computational grids job scheduling quality of service (QoS) performance evaluation MODELING stochastic high-level Petri net (SHLPN)
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A Method for Spatial Heterogeneity Evaluation on Landscape Pattern of Farmland Shelterbelt Networks:A Case Study in Midwest of Jilin Province,China 被引量:11
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作者 SHI Xiaoliang LI Ying DENG Rongxin 《Chinese Geographical Science》 SCIE CSCD 2011年第1期48-56,共9页
On the basis of landscape ecology, combining the Spot 5 high resolution satellite imagery with GIS, a method evaluating the spatial heterogeneity of shelterbelts distribution at landscape scale is put forward in this ... On the basis of landscape ecology, combining the Spot 5 high resolution satellite imagery with GIS, a method evaluating the spatial heterogeneity of shelterbelts distribution at landscape scale is put forward in this paper. The distance coefficients of reasonable and existing landscape indexes of farmland shelterbelt networks were com-puted, and then through the classification of the distance coefficients, and the establishment of evaluation rules, the spatial heterogeneity of farmland shelterbelts was evaluated. The method can improve the evaluating system of previ-ous studies on shelterbelts distribution, resolve the disadvantages of lacking spatiality of overall evaluation, and make the evaluation results have more directive significance for shelterbelt management. Based on this method, spatial het-erogeneity of shelterbelt networks was evaluated in the midwest of Jilin Province, China. The results show that the re-gions with fewer shelterbelts and no closed network account for 34.7% of the total area, but only 4.9% of the area has relative reasonable pattern of shelterbelt networks. Many problems exist in the distribution pattern of shelterbelts, therefore, much attention should be paid to construct farmland shelterbelts in the study area. 展开更多
关键词 farmland shelterbelt spatial heterogeneity Spot 5 distance coefficient
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