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51.
朱韶平 《中国科技信息》2007,33(19):126-127
为了解决异构系统的电子商务过程中流程信息的协同交互,本文探讨了本体论(PSL)和XML的技术特点,设计一个基于XML的流程描述元模型,在语义层次上通过PSL语义定义和映射规则来统一基于XML描述流程信息,实现了流程信息的协同交互。最后通过具体的采购过程实例,验证了该模型及实现方法的可行性。  相似文献   
52.
The method of bibliographic coupling in combination with the complete link cluster method was applied for mapping of the field of organic chemistry with the purpose of testing the applicability of a proposed mapping method on the field level. The method put forward aimed at the generation of cognitive cores of documents, so-called ‘bibliographic cliques’ in the network of bibliographically coupled research articles. The defining feature of these cliques is that they can be considered complete graphs where each bibliographic coupling link ties an unordered pair of documents. In this way, it was presumed that coherent groups of documents in the research front would be found and that these groups would be intellectually coherent as well. Statistical analysis and subject specialist evaluations confirmed these presumptions. The study also elaborates on the choice of observation period and the application of thresholds in relation to the size of document populations.  相似文献   
53.
Pelvis-thorax coordination has been recognised to be associated with swing speed. Increasing angular separation between the pelvis and thorax has been thought to initiate the stretch shortening cycle and lead to increased clubhead speed. The purpose of this study was to determine whether pelvis-thorax coupling played a significant role in regulating clubhead speed, in a group of low-handicap golfers (mean handicap = 4.1). Sixteen participants played shots to target distances determined based on their typical 5- and 6-iron shot distances. Half the difference between median 5- and 6-iron distance for each participant was used to create three swing effort conditions: “minus”, “norm”, and “plus”. Ten shots were played under each swing effort condition using both the 5-iron and 6-iron, resulting in six shot categories and 60 shots per participant. No significant differences were found for X-factor for club or swing effort. X-factor stretch showed significant differences for club and swing effort. Continuous relative phase (CRP) results mainly showed evidence of the stretch shortening cycle in the downswing and that it was more pronounced late in the downswing as swing effort increased. Substantial inter-individual CRP variability demonstrated the need for individual analyses when investigating coordination in the golf swing.  相似文献   
54.
隐喻研究向认知领域扩展开辟了一条从认知角度来研究隐喻的新途径。隐喻的实质就是通过一个认知域映射到另一个认知域的过程。而隐喻映射不可避免要受到文化的制约。如果不了解隐喻映射所依托的文化背景,就会造成隐喻理解的困难。因此,只有了解隐喻映射的认知文化根源,认识到隐喻背后深厚的文化内涵,才能准确理解其喻义。  相似文献   
55.
在数字化采集过程中,当遇到棱镜难于直接安置在目标点时,采用偏心测量方法能够获得较好的测量效果。本文对偏心测量方法进行了一些改进,对实际测量有指导意义。  相似文献   
56.
混沌(chaos)是经过整个20世纪才确立下来的一种复杂运动形式,混沌研究隶属于非线性动力学。混沌现象可谓无处不在,它与分形(Fractal)有着密切的联系。伴随计算机等技术的飞速发展,混沌学已发展成为一门影响深远、发展迅速的前沿科学。  相似文献   
57.
Atmospheric carbon dioxide concentration [CO2], incoming solar radiation and sea ice coverage are among the most important factors that control the global climate. By applying the simple cell-to-cell mapping technique to a simplified atmosphere-ocean-sea ice feedback climate model, effects of these factors on the stability of the climatic system are studied. The current climatic system is found to be stable but highly nonlinear. The resiliency of stability increases with [CO2] to a summit when [CO2] reaches 290 μL/L which is comparable to the pre-industrial level, suggesting carbon dioxide is essential to the stability of the global climate. With [CO2] rising further, the global climate stability decreases, the mean ocean temperature goes up and the sea ice coverage shrinks in the polar region. When the incoming solar radiation is intensified, the ice coverage gradually diminishes, but the mean ocean temperature remains relatively constant. Overall, our analysis suggests that at the current levels of three external factors the stability of global climate is highly resilient. However, there exists a possibility of extreme states of climate, such as a snow-ball earth and an ice-free earth.  相似文献   
58.
定义了基本Fuzzy点空间上的Fuzzy集的直积 ,引进了基本Fuzzy点空间上的Fuzzy拓扑概念 ,讨论了Fuzzy映射连续的条件 .  相似文献   
59.
陈家乾  何衍  蒋静坪 《科技通报》2009,25(4):481-487
为了得到较高的估计精度,基于扩展卡尔曼滤波的同时定位与地图生成算法(EKF-SLAM)需要完成多次路径闭合.这不仅消耗大量的时间与能量,而且增大了机器人发生故障的概率.本文提出一种添加约束的EKF-SLAM算法.该算法通过分析协方差矩阵确定目标路标对,用测量信息与全局先验方向对原估计结果进行约束,能够极大改善估计效果,兼顾高效率与高精度.实验结果及其分析充分表明了算法的有效性.  相似文献   
60.
文章利用信息计量、共引分析、共现分析、信息可视化、社会网络分析等方法,借助CiteSpace信息可视化软件和Ucinet社会网络分析软件,对我国竞争情报研究领域发表的学术论文进行了定量分析,绘制了文献共引、作者共现和关键词共现图谱,直观地展示了我国竞争情报研究的热点领域、核心群体和代表文献。  相似文献   
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