基于全覆盖路径规划的地面搜索问题研究

对简化的地面搜索问题进行研究。首先用最小覆盖原理求出组内每个人的实际搜索半径;考虑组内所有搜索队员作为一个整体沿区域扫描线方向进行搜索,从而可导出一组搜索队伍总的搜索宽度;然后用搜索队伍总的搜索宽度对目标区域进行栅格化;最后采用基于栅格地图的全覆盖路径规划算法对问题1进行求解。对问题2。首先根据时间均衡原则和各组人数均衡原则,确定好各组人数与各组区域优化分配,于是问题2就转化为问题1,便可采用问题1的模型进行求解。理论分析与计算结果表明该方案是可行的。     

INFORMIX数据库系统磁盘I／O性能优化的研究

研究和探讨了INFORMIX数据库应用系统磁盘I／O性能优化问题,提供了两条优化思路和方法,即把数据优化分布在不同磁盘驱动器上和使关键设备独占关键资源。     

信号发生器中D／A转换器接口技术的探讨

D／A转换器是将单片微型计算机送来的数字信号,经转换后变为模拟信号进行输出,DAC0832可以方便地产生各种输出波形,在单片机接口技术中得到了广泛的应用。     

Z39．50客户系统的实现技术探讨

文章介绍近几年来国内外在Z39．50方面的研究与应用,分析了当前Z39．50客户端在设计模式上存在的问题。通过比较了解C／S模式和B／S模式各自的优缺点之后,提出了一种基于半B／S模式的Z39．50客户端的设计方案,并对具体的采用技术进行了初步的探讨。     

国际化视角下的德国“卓越计划”

本文考察了世界强国德国的大学排名表现.论文引用率和其他一些衡量指标数据显示,德国大学未能获得良好的国际认可.本文还分析了德国对此种情况的反应,包括其世界一流大学发展战略.这一战略是集中投入大量资金,试图使一小部分大学在研究和知识创造上取得更好的成绩和更大的国际影响.这种策略来自于对美国和英国一流大学策略的借鉴.但是我们还需意识到,拥有一些顶尖大学和拥有一个优秀的大学体系是两回事.当今所有国家都需要更多拥有更多具有技术能力与创新精神的专业人员,以此发展经济和提供公共服务.如果将优先目标设为与哈佛大学竞争,而不是建设一个庞大且有效的高等教育体系,这将是一个错误的判断.卓越品质,即使是世界一流水平的卓越,也只是有效的教育体系的一个方面.     

六氰合铁酸锰铬修饰电极的原位椭圆偏振表征

采用原位椭圆偏振光谱技术表征了六氰合铁酸锰铬膜（MnCrHCF／Pt）修饰电极。并比较了原位掠射椭圆偏振法、原位反射椭圆偏振法和循环伏安法表征此修饰电极的异同,发现此三种方法在表征修饰电极上有相似之处。     

Promoting complex systems learning through the use of conceptual representations in hypermedia

Studying complex systems is increasingly important in many science domains. Many features of complex systems make it difficult for students to develop deep understanding. Our previous research indicated that a function‐centered conceptual representation is part of the disciplinary toolbox of biologists, suggesting that it is an appropriate representation to help students develop deep understanding. This article reports on the results of two experiments that investigate how hypermedia using a conceptual representation influences pre‐service teachers' and middle school students' learning of a complex biological system, the human respiratory system. We designed two versions of instructional hypermedia based on the structure–behavior‐function conceptual representation. One hypermedia was function‐centered which emphasized the function and behavior of the system, whereas the other was focused on the structure of the system. We contrasted the instructional effectiveness of these two alternative conceptual representations. The results of both studies indicated that participants using the function‐centered hypermedia developed deeper understanding than those using the structure‐centered version. This proof‐of‐concept study suggests that the function‐centered conceptual representation is a powerful way to promote complex systems understanding. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 46: 1023–1040, 2009     

‘In and against the museum’: the contested spaces of museum education for adults

This paper focuses on museum and gallery education for adults in Dundee, Scotland. Dundee has recently experienced a shift from being mainly working class to an educational, cultural and tourist centre. Hence, an interesting field for the examination of the educational policies and practices of the city museums/galleries and the different fashions they receive and act upon wider developments in the museum world has emerged. Questions arising are how the new, open and accessible museum (and gallery) has changed the way education is constructed and offered in the museums in the city? What is the relationship of education with marketing and the new discourse of social inclusion and participation in museums and galleries? For example, one of the most pertinent findings was that, at least in Dundee, activity-based and individual learning has been over-valued, at the expense of a more social and dialogic educational experience that participants seemed to largely prefer and indeed propose as more meaningful to them. Although new ideas and participatory practices have improved attendance and the engagement of the local adult population, other issues, such as the new economic reality for museums and the close relationship of education with marketing are policies that were often treated with resistance, if not opposition, by the research participants.     

‘Who wants to be a travelling teacher?’ Bilingual teachers and weak forms of bilingual education: the Norwegian experience

In this article, I argue that immigrant bilingual teachers and mother‐tongue teachers are not formally recognised as ‘genuine’ teachers in the Norwegian school system. Norwegian education authorities have invested considerable effort in order to strengthen the competences of bilingual teachers and to both recognise and formalise their home country education. Amongst other things, several university colleges were encouraged to provide specially designed higher education programmes for bilingual teachers in order to integrate teachers with bilingual competences into the Norwegian primary school teaching system. This paper is based on data collected in 2007–2008 during the national evaluation of this education, which is the first of its kind in Norway. Although popular amongst immigrant students, it seems that the competences to be gained by graduates of the BA degree programme are not recognised or utilised in the schools where they work. Due to low social status and an unfavourable structural position within the Norwegian school education sector, these teachers will try to distance themselves from their bilingual roles and identities. Within such a framework, the higher education that is intended to strengthen optimum bilingual tuition in the primary schools sector is, in fact, steering bilingual teachers and mother‐tongue teachers away from these more specialised and less valued professions, seeking instead, access into the more mainstream and higher status teaching jobs.     

基于TCP/IP协议的常见攻击方法

TCP/IP协议是目前世界上应用最为广泛的协议.但现在使用的TCP/IP协议存在很多漏洞,对联网主机的安全构成了严重威胁.TCP/IP协议从开始设计时候并没有考虑到现在网络上如此多的威胁,由此导致了许多形形色色的攻击方法.现在就网络中使用的基本通信协议TCP/IP的攻击方法进行探讨.