基于Zigbee的无线温度传感器网络设计与实现

为有效地监控和管理煤矿安全,提高矿井安全生产监控技术,设计并开发了基于ZigBee协议的无线温度传感器网络。该网络由若干分站和探头组成。探头负责将温度传感器所采集到的信息反馈给分站,从而达到对一块区域进行温度监控的目的。实时监测矿工周围环境的温度,预防事故发生。本系统通过软件升级,可以实现人员定位监测,系统附加值高。     

Distributed Teaching Presence and Participants' Activity Profiles: a theoretical approach to the structural analysis of Asynchronous Learning Networks1

The rapid spread of learning networks based on asynchronous written communication — Asynchronous Learning Networks (ALNs) — makes it crucial to assess the possibilities offered by these new environments to facilitate and promote learning processes and learning outcomes. Our interest in this area is specifically directed towards the study of distributed teaching presence understood as the exercise of educational influence, i.e. as the help provided to each other participant in an ALN to promote individual and collective learning. We adopt a multi-method approach that integrates the structural analysis of presence (access and participation) and connectivity (reciprocity and responsiveness) with the content analysis of the participants’ contributions. This article focuses on structural analysis as a relevant and powerful tool for the study of collaborative learning in networking and asynchronous contexts. Its main objective is to show how a relevant and useful system of indicators and profiles, which identify and examine the distribution of educational influence in ALNs, can be constructed. We present the theoretical assumptions surrounding the concept of distributed teaching presence and illustrate the analysis with data from two didactic sequences in higher education. The results show that the structural analysis, when theoretically grounded and oriented, is a powerful tool for identifying different activity profiles related to different levels and modalities of the exercise of educational influence and for assessing the distributed teaching presence in learning networks. Finally, we discuss the benefits and constraints of this kind of analysis.     

十六大以来中国农村改革进程的基本判断与前瞻

十六大以来,中国新一轮农村改革发展的一条主线是"多予、少取、放活"。目前,农村税费改革已取得了阶段性的巨大成功,国民收入分配结构和财政支出结构正向农村地区倾斜,"三农"问题初步得到了缓解,我国在总体上进入到了"后农业税时代"和"工业反哺农业、城市支持农村"新的发展阶段。下一步深化农村改革的重点、难点是,逐步消除城乡二元体制对经济社会协调发展所造成的瓶颈制约,从根本上解决"三农"问题的深层次矛盾和体制性障碍;最大的突破口选择是加快推进农村综合配套改革,进一步做好"放活"这篇大文章,充分发挥9亿农民的市场主体地位和作用,激发农民自我发展和自我积累的巨大潜能,不断提高和增强农业和农村经济发展的内部活力。这是我国在本世纪头20年实现全面建设小康社会目标的根本途径。     

Next generation network environments in Europe — The significance of the EU as a policy actor

The relatively new topic of Next Generation Networks (NGN) is one which is ascending rapidly communications policy agendas in Europe and beyond. How these networks might be created and, beyond that, how they might function in a sustained and broadly useful manner, and the implications of this, are issues which crystallise a raft of often complex policy concerns that have emerged, for at least a decade, in historically distant though increasingly connected quarters of electronic network communications. This article breaks new ground in the analysis of the emerging role of the EU by exploring EU NGN policy from a convergence infrastructural and content perspective. Whilst at this stage, despite new ‘policy packaging’, the EU's NGN policy activity is resonant of past telecommunications and audiovisual policies, the article contends that there are key areas where the EU can exercise considerable policy leverage through utilising a combination of formal legal and soft governance capacities. This has a greater chance of materialising how the more transnational NGN networks and services become.     

离散时间的混合时滞耦合神经网络的鲁棒指数同步

讨论了一类离散时间的时滞耦合神经网络的同步问题.在参教不确定的离散时间耦合神经网络中,考虑了变时滞和有限分布时滞.同时,细胞激活函数假设为较Lipschitz奈件更为一般的扇形非线性函数,该函数可以既不可微又不严格单调.通过构造Lyapunov-Krasovskii泛函,运用线性矩阵不等式(LMI)技术,并结合Kronecker积来获得耦合神经网络鲁棒全局指数同步的充分性判据,并且所获得的判据依赖于时滞.最后,对一个实例进行仿真,说明结论的有效性.     

从弑父向寻父的转变：晚生代创作转型研究

新世纪以来,随着一批以写农村题材为主的文学作品的问世,毕飞宇、李洱、林白等为中坚的晚生代作家的创作出现了转型迹象,开始有意无意从欲望都市中撤退,在乡村和历史中进行书写,显示了对写作深度和写作意义的自觉思考和追问,呈现了某种历史主义的悲悯情怀。与这种空间的转换相对应的,还有叙事立场从原先的边缘向中心的靠拢,叙事方式上从现时态的写作向过去式的写作,话语方式从原先的反讽式写作向悖论式写作转向,这些文本中呈现出了一种人到中年的精神气质,与现实和解,向历史握手。这种写作固然源于作家写作的探索,更源于现实的召唤,还来自于人到中年的生命体验。     

充分发挥“关工委”作用,为学校改革与发展作贡献

加强和改进高校＂关工委＂工作是形势发展的需要,要结合高校实际,建立健全体制机制,保障＂关工委＂工作的顺利进行;要更新概念、创新思路,不断开创高校＂关工委＂工作新局面。     

郑州市新生代农民工城市社会融入特点及对策研究

近年来,城市农民工群体内部的代际分化已经形成,新生代农民工成为农民工群体的主力军。这一群体在城市社会的融入过程中形成了自己的特点,即目标明确,但困难重重;幸福感增强,但幸福指数不高;行为消费更倾向于城市化,但支出增加;法律意识增强,但维权意识有待提高;受教育程度提高,但专业技能培训不够;创业热情高,但失败率也高。因此,要加强新生代农民工城市社会融入的对策研究,实现他们由城市"边缘人"向城市市民的转化期盼。     

A latecomer's strategy to promote a technology standard: The case of Datang and TD-SCDMA

This paper studied the key strategies used by Datang, a local Chinese firm, to promote TD-SCDMA in order to explore an under-researched topic: how could a latecomer promote a technology standard? The findings suggest that Datang faced formidable challenges because of latecomer disadvantage and transitional institutions. The development of innovation capabilities and new technologies is needed but far from sufficient. It is necessary to develop special capabilities to get support from the government and public stakeholders such as scholars. The experience of Datang offers new insights into the development and adoption of technology standards sponsored by latecomers in developing countries.     

基于无线传感器网络的革命遗址保护研究

为推动红色旅游,急需对原中央苏区革命遗址进行保护。提出一种部分节点移动的无线传感器网络,构建一个对革命遗址有效保护的环境监测自动化系统,给出了系统的总体结构。在路由通信方面采用贪婪地理路由协议进行路由选择,对网络拓扑变化有较好的自适应性,实现了无线传感器网络能量高效的自适应信标交换和负载均衡贪婪转发策略。仿真实验表明,该网络减少了数据分组的丢失,缓解了在高业务量情况下的拥塞程度,具有较高的实用价值和应用前景。