新型锁相环在频率跟踪技术中的研究

在比较电力系统频率跟踪技术中软硬件同步优缺点的基础上,提出了一种基于FPGA的全数字锁相环(ADPLL)电路实现电力系统频率跟踪的技术;将FPGA技术运用于同步跟踪技术中,解决了软硬同步方法中的各个不足之处;全数字锁相环电路采用VHDL语言和FPGA设计,仿真波形和实验结果表明,该电路能够很好地跟踪电网频率的实时变化,相位误差仅为0.1%,频率测量误差仅为0.06%,实现了同频率同相位的锁定;速度快、精度高;对电网的谐波计算有较大的实际意义.     

菏泽民俗文化符号在旅游商品转化中的应用

本文从旅游商品的概念和山东菏泽地域文化资源现状出发,探讨了菏泽民俗文化旅游商品的现状,并针对菏泽旅游商品研发存在的问题,从菏泽地域文化的挖掘及其在旅游商品的转化方式上进行了分析,提出了民俗文化旅游纪念品开发的对策,以期推动民俗文化产业和旅游产业的健康发展。     

A proposal for student modeling based on ontologies and diagnosis rules

The advances in the educational field and the high complexity of student modeling have provoked it to be one of the aspects more investigated in Intelligent Tutoring Systems (ITSs). The Student Models (SMs) should not only represent the student’s knowledge, but rather they should reflect, as faithfully as possible, the student’s reasoning process. To facilitate this goal, in this article a new approach to student modeling is proposed that benefits from the advantages of Ontological Engineering, advancing in the pursue of a more granular and complete knowledge representation. It’s focused, mainly, on the SM cognitive diagnosis process, and we present a method providing a rich diagnosis about the student’s knowledge state – especially, about the state of learning objectives reached or not. The main goal is to achieve SMs with a good adaptability to the student’s features and a high flexibility for its integration in varied ITSs.     

基于ZigBee的多机器人通信系统的设计

为解决多机器人协作的问题,设计了可以让机器人之间基于ZigBee网络进行通信的通信方案。机器人硬件系统中引入了ZigBee节点,多个机器人依赖ZigBee形成一个星型网络,每个机器人可以通过中心节点保持通信。实验结果表明,机器人之间可以可靠地进行通信,能够显著提高机器人的工作效率。     

高灵敏巨磁阻抗小型磁传感器研制

利用单辊快淬法制备了CoFeNiSiB非晶薄带,经过400 A/mm2电流密度、20 ms脉冲间隔条件下的脉冲退火后具有较好的弱磁场灵敏性能.以该带材为磁敏材料,基于纵向驱动方式研制了一种巨磁阻抗(GMI)磁传感器,该磁传感器尺寸小、灵敏度高、频率响应好,±0.05 mT弱磁场范围内灵敏度可达到44.15 V/mT,在高灵敏度小型磁传感器领域具有较大的应用潜力.     

AMSR-E卫星反演土壤湿度与ECWMF,NECP再分析土壤湿度比较分析

土壤湿度是气象学、气候学研究领域的重要环境因子和过程参数。AMSR-E可提供全球范围的较长时序的卫星反演土壤湿度产品,将ECWMF和NECP再分析资料与AMSR-E土壤湿度产品进行时空比较,在评价三者一致性的同时对AMSR-E土壤湿度进行检验,并进一步使用站点观测资料(土壤湿度、降水量)对中国区域的AMSR-E、ECWMF以及NECP土壤湿度进行检验。结果表明：全球及中国区域AMSR-E、ECWMF与NECP土壤湿度空间分布特征一致性较好,但与ECWMF、NCEP相比AMSR-E土壤湿度在数值上明显偏小,尤其当AMSR-E土壤湿度数值较小时,与另两者的差距较大;三者土壤湿度均与降水量有较好的对应关系,比较而言,ECWMF和NECP土壤湿度与降水量的对应关系更好;与站点土壤湿度相比,ECWMF和NECP土壤湿度偏大,AMSR-E土壤湿度偏小,全国范围内2009年159个站点统计结果显示:ECWMF、NECP与站点的均方根误差(0.107、0.124)小于AMSR-E的均方根误差(0.127)。     

How useful are strategic plans for information systems?

Although much research has been done in the area of strategic planning for information systems (IS), relatively less research has focused on the output of the IS planning process, namely, the IS plan. This paper examines the usefulness of IS plans through a field survey of 136 IS executives. Results indicate that IS plans are generally perceived to be useful for supporting business objectives, improving systems integration, exploiting information technology (IT) for competitive advantage, and prioritising IS development projects. Conversely, IS plans are perceived to be less useful for clarifying the role of IS, evaluating IS performance, anticipating surprises and crisis, and adapting to unanticipated situations. Implications of these results are discussed.     

Improved MCMAC with momentum, neighborhood, and averagedtrapezoidal output

An improved modified cerebellar articulation controller (MCMAC) neural control algorithm with better learning and recall processes using momentum, neighborhood learning, and averaged trapezoidal output, is proposed in this paper. The learning and recall processes of MCMAC are investigated using the characteristic surface of MCMAC and the control action exerted in controlling a continuously variable transmission (CVT). Extensive experimental results demonstrate a significant improvement with reduced training time and an extended range of trained MCMAC cells. The improvement in recall process using the averaged trapezoidal output (MCMAC-ATO) are contrasted against the original MCMAC using the square of the Pearson product moment correlation coefficient. Experimental results show that the new recall process has significantly reduced the fluctuations in the control action of the MCMAC and addressed partially the problem associated with the resolution of the MCMAC memory array.     

BaPbO3／BaTiO3系复合陶瓷的研究

报道了导电陶瓷ＢａＰｂＯ３与铁电陶瓷ＢａＴｉＯ３进行复合的结果，研究了该复合功能陶瓷的物相、导电性和低温电阻温度特性。结果表明：采用合理的合成工艺，可得到呈现混和分布的两相复合功能陶瓷材料，该复合材料的电导特征符合三维渗流导电行为。