无线传感器网络研究

无线传感器网络集成了传感器、微机电系统和网络三大技术而形成的传感器网络是一种全新的信息获取和处理技术,已经成为当今的热门研究领域之一,在国防安全、工农业领域各种控制、城市管理、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等许多领域都有重要的科研价值和实用价值,具有十分广阔的应用前景。本文讨论了无线传感器网络的基本概念和一些重要研究领域,并且介绍了无线传感器网络与IPv6的可能的一些契合点,它是无线传感器网络进行大规模就用的重要议题。     

我国微生物学基础研究现状及展望

本文简要回顾了国家自然科学基金委员会成立19年来对微生物学科的 资助情况，并对微生物学在我国的研究状况、微生物学研究热点及发展趋势进行了分析。     

无线自组网路由协议分析

路由协议是无线自组网非常重要的协议之一,本文全面介绍了无线自组网的路由协议.先从面临的问题、设计的基本思想和要求这些方面阐述了无线自组网路由协议当前的基本情况;最后根据分类情况对路由协议进行分析和比较.     

移动自组织网络中QoS路由协议研究

随着移动自组织网络(MANET)的应用领域日益扩大,要求它必须提供一定的服务质量(QoS)保证,而QoS路由协议是MANET支持QoS的一个关键理论和技术,也是目前的一个研究热点。本文对当前自组织网络的QoS主要路由协议进行了详细的分析与研究,并从路由机制、单向链路的支持、多播功能、QoS参数选择以及节能几个方面进行了比较和分析;最后指出了今后的研究方向。     

Islamic Historians of the Ayyūbid Era and Muslim Rulers from the Early Crusading Period: A Study in the Use of History

This article examines the presentation of Muslim rulers from the early crusading period, 490–540/1097–1146 in six of the main chronicles written during the first half of the seventh/thirteenth century. It discusses the themes, ideas and topoi in each, demonstrating that the historians appear to have been divided into two ‘camps’ over their presentation of these rulers, based on their personal views of the rulers of their time. The article also examines why this division may have occurred, and considers its ramifications for modern scholarship of Arabic historiography, Islamic history and the history of the Crusades, in both the sixth/twelfth and seventh/thirteenth centuries.     

基于不同VANET应用的路由协议选择分析

不同VANET应用对网络属性的要求和各自的特性影响路由协议的选择和使用。选择合适的路由协议将实现更好的网络性能,提供更高效的服务。通过分析VANET的5类应用的特点和对网络的要求,结合不同种类路由协议的特性,主要针对单播和多播情况下路由协议选择原因进行阐述,并给出单播协议中GPSR＋AGF和CAR这两种路由协议的构造方式。     

农村中学体育术科生训练中的几种现象与对策——以江门新会陈瑞祺中学为例

农村中学体育术科考生在平时的运动训练中,有几种现象直接或间接地影响到了考生的考试成绩,农村体育考生选择了体育作为自己的通往大学之路,带训体育教师,文章对农村体育术科考生训练中的几种现象加以分析,找出对策,总结一些有效的训练经验,为考生取得良好的成绩提供帮助。     

Sitting on the Fence: Integrating the two worlds of scientific discovery and invention within the firm

Applying a within-firm perspective to the topic of the division of innovative labor, I explore the organization of scientific discovery at the firm level — specialized or integrated with invention. Using data on inventors and authors related to U.S. publicly-traded science-performing firms for the period 1980–2015, the paper deepens our understanding of the determinants and the tradeoffs associated with the strategic choice of scientific discovery organization. I show that integration is related to a tradeoff between short-term applied R&D and long-term fundamental R&D; while integration is beneficial for invention, it has adverse effects on its scientific output, which decrease invention in the long run. The negative relationship between integration and publication reduces the direct increase in patents due to integration by approximately 90%. To better understand firms’ R&D organizational choice, I present internal and external factors that have implications on the benefits and costs associated with integration: reliance on science, stage of technology, external market for technology, and R&D spillins. Finally, I present consistent implications in terms of market value and show that value creation is related to organizational structure.     

试论成吉思汗的社会及家庭分工思想

成吉思汗是一位具有平等职业观念、辩证分工思想、注重实际、敢于向他人学习、勇于社会实践、善于发展自己、有开放型思维方式的开明君主。他平等对待各种职业，重视发展蒙古农业、手工业和商业贸易，开创了一条以牧为主，多种经营的民族经济发展之路。他提倡男女平等，制定和实施灵活而辩证的家庭分工原则，有效利用了牧区剩余劳动力，解放和发展了草原生产力，极大地推动了蒙古社会的进步．如今，继承和发杨这一优秀文化传统，对于提高整个民族素质，顺应时代潮流，走向市场经济，都具有十分重要的理论和现实的启发意义。     

Relevance-based entity selection for ad hoc retrieval

Recent developments have shown that entity-based models that rely on information from the knowledge graph can improve document retrieval performance. However, given the non-transitive nature of relatedness between entities on the knowledge graph, the use of semantic relatedness measures can lead to topic drift. To address this issue, we propose a relevance-based model for entity selection based on pseudo-relevance feedback, which is then used to systematically expand the input query leading to improved retrieval performance. We perform our experiments on the widely used TREC Web corpora and empirically show that our proposed approach to entity selection significantly improves ad hoc document retrieval compared to strong baselines. More concretely, the contributions of this work are as follows: (1) We introduce a graphical probability model that captures dependencies between entities within the query and documents. (2) We propose an unsupervised entity selection method based on the graphical model for query entity expansion and then for ad hoc retrieval. (3) We thoroughly evaluate our method and compare it with the state-of-the-art keyword and entity based retrieval methods. We demonstrate that the proposed retrieval model shows improved performance over all the other baselines on ClueWeb09B and ClueWeb12B, two widely used Web corpora, on the [email protected], and [email protected] metrics. We also show that the proposed method is most effective on the difficult queries. In addition, We compare our proposed entity selection with a state-of-the-art entity selection technique within the context of ad hoc retrieval using a basic query expansion method and illustrate that it provides more effective retrieval for all expansion weights and different number of expansion entities.