“Bring Your Own Device (BYOD)” for seamless science inquiry in a primary school

This paper reports a one-year study on the project of “Bring Your Own Device (BYOD) for seamless science inquiry” in a primary school in Hong Kong. BYOD in this study refers to “the technology model where students bring a personally owned mobile device with various apps and embedded features to use anywhere, anytime for the purpose of learning”. The study aims at investigating (a) what advancement of content knowledge students made in their science inquiry in a seamless learning environment supported by their own mobile device; (b) how the students advanced their content knowledge in science inquiry; and (c) what students' perception is regarding their learning experience supported by their own mobile devices. The topic of inquiry was “The Anatomy of Fish”. Data collection included pre- and post-domain tests, self-reported questionnaire, student artifacts, class observations and field notes. Content analysis and a student artifact tracing approach were adopted in the data analysis to examine and trace students' knowledge advancement. The research findings show that the students advanced their understanding of the anatomy of fish well beyond what was available in the textbook and they developed positive attitude toward seamless science inquiry supported by their own mobile devices.     

BECKHOFF多通道技术在汽车纵梁生产线上的运用

随着现代汽车工业的发展,汽车生产制造技术对新工艺新技术提出了更高要求。本文基于BECKHOFF双通道技术,对加工设备的动作工艺进行改进,可切实有效地实现各轴运转的无缝对接,进一步缩短生产周期,增加企业竞争力。     

高层建筑无线网络优化研究

当前城市高层建筑用户投诉量大,比重高.高层覆盖质量问题的解决一直是通信行业界的难点.本文围绕高层楼宇覆盖特点、常见问题处理措施、典型高层场景问题展开研究,给出了高层楼宇场景下的问题解决方案及处理流程.     

浅析我国企业年金发展的必要性和存在的问题

论述了企业年金是企业为职工设立的一种介于国家基本养老保险与个人商业养老保险之间的补充性养老保险制度,企业年金的顺利发展关系到社会的稳定、国家的和谐发展,是人们普遍关心的问题。     

关于我国钢管行业发展战略的思考(下)

分析了我国钢管行业面临的形势,指出目前我国虽然保持钢管生产和消费大国的地位,但随着国内市场的日趋国际化,钢管行业面临着更加激烈的国际竞争。建议“十一五”期间,中国钢管行业应该实施以调整产业及产品结构为中心,开发研究高档次专用管材为重点的发展战略。     

A relationship between software coverage metrics and reliability

Software engineers have tacitly assumed that there exists a link between coverage and reliability. An argument is presented which leads to an inverse logarithmic relationship which depends upon the structure of the software and on a parameter called the strength of the coverage metric. The relationship is developed by considering reliability as a function of an idealized coverage metric and then interpreting the result for a range of actual coverage metrics.     

无线传感器网络密度控制研究

无线传感器网络节点能量受限,部署环境恶劣、复杂。在监测区域内部署大量节点,通过节点之间的状态轮换与合作策略延长网络寿命是非常重要的方法。本文论述了设计密度控制算法状态转移条件需要解决的两个基本问题：区域覆盖问题和节点连通性优化问题,并分别以ILP的形式给出了一个集中式算法解决方案。通过节点的覆盖效用范围与连通性效用范围的几何分析,提出了传感器网络密度控制算法中解决两个基本问题的一致性策略。     

基于SIS与DCS集成的罐区安全控制

烃类球罐区属于重大危险源,DCS系统在安全控制方面存在诸多漏洞,一旦发生事故就不可控,因此,SIS系统的应用势在必行。依据IEC61511、IEC61508标准,从技术经济角度对比分析SIS与DCS几种不同集成方案的可行性,结合齐隆化工C5球罐区工艺设计对SIL进行安全定量评估,并针对齐隆化工在SIS与DCS无缝集成系统在安全控制方面存在的问题,提出适合企业现状的解决方案。     

近年来俄罗斯无缝钢管工业的结构调整

综述了近年来俄罗斯无缝钢管工业的结构调整情况；分析研究了近年来俄罗斯无缝钢管工业的整体发展情况和所取得的技术进步，以及无缝钢管产品的进出口量变化和钢管产品结构调整情况；介绍了俄罗斯两大无缝钢管生产集团近年来的生产经营和核心竞争力增强的情况。     

Coverage path planning for UAVs based on enhanced exact cellular decomposition method

In this paper, an enhanced exact cellular decomposition method to plan the coverage path of UAVs in a polygon area is proposed. To be more specific, the contributions of the paper are: firstly, the turning motion of UAVs is shown to be less efficient from the viewpoints of route length, duration and energy. Secondly, the problem of coverage Path Planning (CPP) in a convex polygon area is transformed to width calculation of the convex polygon, and a novel algorithm to calculate the widths of convex polygons with time complexity of O(n) is developed. The path of the least number of turns for an UAV based on the widths of convex polygons is devised. Thirdly, a convex decomposition algorithm for minimum width sum based on the greedy recursive method which revolves around decomposing the concave area into convex subregions is developed. It is proved that the algorithm is a polynomial time algorithm. To avoid unnecessary back and forth motion, some entirely adjacent subregions are combined. Finally, comparing different weights of two joint-points, a subregion connection algorithm based on minimum traversal of weighted undirected graph is proposed to connect the coverage paths of the subregions. Simulation results show that the proposed method is feasible and effective.