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901.
Elena García-Barriocanal Miguel-Angel Sicilia Miltiadis Lytras 《Computers in human behavior》2007,23(6):2641
The use of toolkits and reference frameworks for the design and evaluation of learning activities enables the systematic application of pedagogical criteria in the elaboration of learning resources and learning designs. Pedagogical classification as described in such frameworks is a major criterion for the retrieval of learning objects, since it serves to partition the space of available learning resources depending either on the pedagogical standpoint that was used to create them, or on the interpreted pedagogical orientation of their constituent learning contents and activities. However, pedagogical classification systems need to be evaluated to assess their quality with regards to providing a degree of inter-subjective agreement on the meaning of the classification dimensions they provide. Without such evaluation, classification metadata, which is typically provided by a variety of contributors, is at risk of being fuzzy in reflecting the actual pedagogical orientations, thus hampering the effective retrieval of resources. This paper describes a case study that evaluates the general pedagogical dimensions proposed by Conole et al. to classify learning resources. Rater agreement techniques are used for the assessment, which is proposed as a general technique for the evaluation of such kind of classification schemas. The case study evaluates the degree of coherence of the pedagogical dimensions proposed by Conole et al. as an objective instrument to classify pedagogical resources. In addition, the technical details on how to integrate such classifications in learning object metadata are provided. 相似文献
902.
Experimental field load-test and finite-element analysis were carried out for the performance assessment of a precast-concrete, modular, three-sided, low-profile, buried, arch bridge system. Finite-element analysis incorporated soil modeling and soil–structure interaction at service and limit load levels. The analytical study simulates step-by-step incremental phases of construction and service loads. The finite-element model was calibrated based on the experimental field assessment, to provide a better correlation between the analytically predicted behavior and the actual response of the structure. The study validates the incorporation of various soil models and soil–structure interaction characteristics, to allow a more cost-effective bridge design. 相似文献
903.
浅谈高速公路设计应注意的若干问题 总被引:1,自引:1,他引:0
通过对公路平、竖线形设计、路基软基处理和提高路基水稳定性,以及桥涵等结构物的设计等方面应考虑的问题进行了分析,介绍了从三大控制角度合理确定结构物的取材,从设计角度提高三背回填的质量,以提高高速公路的施工工艺水平。 相似文献
904.
Findings from 3 experiments suggest that participants who were actively engaged in goal pursuit, compared with those who were not pursuing the goal, automatically evaluated goal-relevant objects as relatively more positive than goal-irrelevant objects. In Experiment 3, participants' automatic evaluations also predicted their behavioral intentions toward goal-relevant objects. These results suggest the functional nature of automatic evaluation and are in harmony with the classic conceptualization of thinking and feeling as being in the service of "doing" (e.g., S. T. Fiske, 1992; W. James, 1890; K. Lewin, 1926) as well as with more recent work on the cognitive mechanics of goal pursuit (e.g., G. B. Moskowitz, 2002; J. Y. Shah & A.W. Kruglanski, 2002). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
905.
梁政 《西南石油学院学报》1991,13(1):78-84
本文在简单评述现有分析方法的基础上,提出了一种新的计算模型。经理论分析,获得了较为满意的解答。文末用算例说明了有关参数的影响,并与现有结果进行了对比分析。 相似文献
906.
Parallel database systems: Open problems and new issues 总被引:8,自引:0,他引:8
Patrick Valduriez 《Distributed and Parallel Databases》1993,1(2):137-165
Parallel database systems attempt to exploit recent multiprocessor computer architectures in order to build high-performance and high-availability database servers at a much lower price than equivalent mainframe computers. Although there are commercial SQL-based products, a number of open problems hamper the full exploitation of the capabilities of parallel systems. These problems touch on issues ranging from those of parallel processing to distributed database management. Furthermore, it is still an open issue to decide which of the various architectures among shared-memory, shared-disk, and shared-nothing, is best for database management under various conditions. Finally, there are new issues raised by the introduction of higher functionality such as knowledge-based or object-oriented capabilities within a parallel database system. 相似文献
907.
908.
909.
Objects can be viewed as entities reacting concurrently with their environment through the sending and receiving of messages. In this paper a model for such reactive objects is constructed where messages may be blocked either by the object or by the environment. This model differentiates between output messages controlled by the object, and input messages controlled by the environment. The model is applied to define an object compatibility lattice structure enabling the construction of objects satisfying best possible compatibility requirements. 相似文献
910.
本文利用矢量波函数变换方法讨论了两媒质半空间的电磁散射问题,从Maxwell方程出发,讨论了单矩法在三维复杂形体散射问题上的实施。并在数学球面上将内部区域的有限元解与外部区域矢量波函数变换的结果相匹配,从而得到复杂埋入体的电磁散射特性。作为检验和示例,本文计算了在平面波照射下自由空间导体球,埋入导体球,埋入介质覆盖钝锥等的散射场,其中一些结果与可供比较的经典解或其它算法的结果进行了比较,吻合较好。 相似文献