In this paper, a new mechanism for the emergence of scale-free distribution is proposed. It is more realistic than the existing mechanism. Based on our mechanism, a model responsible for the scale-free distribution wi...In this paper, a new mechanism for the emergence of scale-free distribution is proposed. It is more realistic than the existing mechanism. Based on our mechanism, a model responsible for the scale-free distribution with an exponent in a range of 3-to-5 is given. Moreover, this model could also reproduce the exponential distribution that is discovered in some real networks. Finally, the analytical result of the model is given and the simulation shows the validity of our result,展开更多
Wireless Sensor Networks for Rainfall Monitoring (RM-WSNs) is a sensor network for the large-scale regional and moving rainfall monitoring,which could be controlled deployment. Delivery delay and cross-cluster calcula...Wireless Sensor Networks for Rainfall Monitoring (RM-WSNs) is a sensor network for the large-scale regional and moving rainfall monitoring,which could be controlled deployment. Delivery delay and cross-cluster calculation leads to information inaccuracy by the existing dynamic collabo-rative self-organization algorithm in WSNs. In this letter,a Local Dynamic Cluster Self-organization algorithm (LDCS) is proposed for the large-scale regional and moving target monitoring in RM-WSNs. The algorithm utilizes the resource-rich node in WSNs as the cluster head,which processes target information obtained by sensor nodes in cluster. The cluster head shifts with the target moving in chance and re-groups a new cluster. The target information acquisition is limited in the dynamic cluster,which can reduce information across-clusters transfer delay and improve the real-time of information acquisition. The simulation results show that,LDCS can not only relieve the problem of "too frequent leader switches" in IDSQ,also make full use of the history monitoring information of target and con-tinuous monitoring of sensor nodes that failed in DCS.展开更多
This paper presents Isotope, an efficient, locality aware, fault-tolerant, and decentralized scheme for data location in distributed networks. This scheme is designed based on the mathematical model of decentralized l...This paper presents Isotope, an efficient, locality aware, fault-tolerant, and decentralized scheme for data location in distributed networks. This scheme is designed based on the mathematical model of decentralized location services and thus has provable correctness and performance. In Isotope, each node needs to only maintain linkage information with about O(log n) other nodes and any node can be reached within O(log n) routing hops. Compared with other related schemes, Isotope’s average locating path length is only half that of Chord, and its locating performance and locality-awareness are similar to that of Pastry and Tapestry. In addition, Isotope is more suitable for constantly changing networks because it needs to exchange only O(log n) O(log n) messages to update the routing information for nodes arrival, departure and failure.展开更多
Localization technology is an important support technology for WSN(Wireless Sensor Networks). The centroid algorithm is a typical range-free localization algorithm, which possesses the advantages such as simple locali...Localization technology is an important support technology for WSN(Wireless Sensor Networks). The centroid algorithm is a typical range-free localization algorithm, which possesses the advantages such as simple localization principle and easy realization. However, susceptible to be influenced by the density of anchor node and uniformity of deployment, its localization accuracy is not high. We study localization principal and error source of the centroid algorithm. Meanwhile, aim to resolve the problem of low localization accuracy, we proposes a new double-radius localization algorithm, which makes WSN node launch periodically two rounded communications area with different radius to enable localization region to achieve the second partition, thus there are some small overlapping regions which can narrow effectively localization range of unknown node. Besides, partition judgment mechanism is proposed to ascertain the area of unknown node, and then the localization of small regions is realized by the centroid algorithm. Simulation results show that the algorithm without adding additional hardware and anchor nodes but increases effectively localization accuracy and reduces the dependence on anchor node.展开更多
为解决计算机网络面临的数据隐私、终端性分布不均等问题,扩大计算机网络的应用范围,结合局域网(Local Area Network,LAN)环境研究计算机网络安全技术的有效应用。由于局域网是互联网的重要组成部分之一,要想保证计算机网络的安全应当...为解决计算机网络面临的数据隐私、终端性分布不均等问题,扩大计算机网络的应用范围,结合局域网(Local Area Network,LAN)环境研究计算机网络安全技术的有效应用。由于局域网是互联网的重要组成部分之一,要想保证计算机网络的安全应当加强对安全技术、数据加密技术等技术的应用。基于此,提出了一种基于局域网环境的网络安全体系设计,以期为局域网中的计算机网络安全发展提供相应的参考。展开更多
在互联网时代的宏观背景下,需要了解基于IP无线接入网(IP Radio Access Network,IPRAN)的主要作用。在本地网组网技术模式研究中,可以利用分组传输的数据值,通过设备实现基站业务回传和专线业务综合接入。IPRAN有极高的便捷性和兼容性,5...在互联网时代的宏观背景下,需要了解基于IP无线接入网(IP Radio Access Network,IPRAN)的主要作用。在本地网组网技术模式研究中,可以利用分组传输的数据值,通过设备实现基站业务回传和专线业务综合接入。IPRAN有极高的便捷性和兼容性,5G综合业务接入网IPRAN是未来的重要发展趋势,具有高品质、多点化服务特征。在承载需求上,从长期演进(Long Term Evolution,LTE)角度出发,依托区域骨干网对IPRAN组网各设备的构建和组网需求进行分析,实现综合业务接入网IPRAN的本地网组网技术模式的规划完善。展开更多
由于无线网络主要在开放的空间环境内展开数据信息传输,而不是固定在物理线缆上,存在一定的安全隐患。因此,必须要优化落实对无线网络的安全防护。文章强调了无线局域网(Wireless Local Area Network,WLAN)安全防护的必要性,并对恶意攻...由于无线网络主要在开放的空间环境内展开数据信息传输,而不是固定在物理线缆上,存在一定的安全隐患。因此,必须要优化落实对无线网络的安全防护。文章强调了无线局域网(Wireless Local Area Network,WLAN)安全防护的必要性,并对恶意攻击、非法用户入侵、重传攻击等影响计算机无线网络安全的主要因素进行了分析。在此基础上,从无线与有线一体化关联分析技术、无线网络安全保障机制、WLAN安全技术这几方面入手,着重阐述了基于WLAN的网络安全防护技术的具体应用,以营造更为安全的WLAN无线网络运行环境。展开更多
基金Project supported by the National Natural Science Foundation of China （Grant Nos 60374037 and 60574036）, the Program for New Century Excellent Talents of High Education of China（Grant No NCET 2005-290）, The Special Research Fund for the Doctoral Program of High Education of China （Grant No 20050055013）.Acknowledgments The authors would like to thank Réka Albert for useful discussion and are grateful to the anonymous referees for their valuable suggestions and comments, which have made this paper improved.
文摘In this paper, a new mechanism for the emergence of scale-free distribution is proposed. It is more realistic than the existing mechanism. Based on our mechanism, a model responsible for the scale-free distribution with an exponent in a range of 3-to-5 is given. Moreover, this model could also reproduce the exponential distribution that is discovered in some real networks. Finally, the analytical result of the model is given and the simulation shows the validity of our result,
基金Supported by the Key Projection of Science and Technology Research of Ministry of Education of China (107057)the Science & Technology Fund for Students of Hohai University (K200803)
文摘Wireless Sensor Networks for Rainfall Monitoring (RM-WSNs) is a sensor network for the large-scale regional and moving rainfall monitoring,which could be controlled deployment. Delivery delay and cross-cluster calculation leads to information inaccuracy by the existing dynamic collabo-rative self-organization algorithm in WSNs. In this letter,a Local Dynamic Cluster Self-organization algorithm (LDCS) is proposed for the large-scale regional and moving target monitoring in RM-WSNs. The algorithm utilizes the resource-rich node in WSNs as the cluster head,which processes target information obtained by sensor nodes in cluster. The cluster head shifts with the target moving in chance and re-groups a new cluster. The target information acquisition is limited in the dynamic cluster,which can reduce information across-clusters transfer delay and improve the real-time of information acquisition. The simulation results show that,LDCS can not only relieve the problem of "too frequent leader switches" in IDSQ,also make full use of the history monitoring information of target and con-tinuous monitoring of sensor nodes that failed in DCS.
基金Sponsored by the National Natural Science Foundation of China(Grant No.60073074).
文摘This paper presents Isotope, an efficient, locality aware, fault-tolerant, and decentralized scheme for data location in distributed networks. This scheme is designed based on the mathematical model of decentralized location services and thus has provable correctness and performance. In Isotope, each node needs to only maintain linkage information with about O(log n) other nodes and any node can be reached within O(log n) routing hops. Compared with other related schemes, Isotope’s average locating path length is only half that of Chord, and its locating performance and locality-awareness are similar to that of Pastry and Tapestry. In addition, Isotope is more suitable for constantly changing networks because it needs to exchange only O(log n) O(log n) messages to update the routing information for nodes arrival, departure and failure.
文摘Localization technology is an important support technology for WSN(Wireless Sensor Networks). The centroid algorithm is a typical range-free localization algorithm, which possesses the advantages such as simple localization principle and easy realization. However, susceptible to be influenced by the density of anchor node and uniformity of deployment, its localization accuracy is not high. We study localization principal and error source of the centroid algorithm. Meanwhile, aim to resolve the problem of low localization accuracy, we proposes a new double-radius localization algorithm, which makes WSN node launch periodically two rounded communications area with different radius to enable localization region to achieve the second partition, thus there are some small overlapping regions which can narrow effectively localization range of unknown node. Besides, partition judgment mechanism is proposed to ascertain the area of unknown node, and then the localization of small regions is realized by the centroid algorithm. Simulation results show that the algorithm without adding additional hardware and anchor nodes but increases effectively localization accuracy and reduces the dependence on anchor node.
文摘为解决计算机网络面临的数据隐私、终端性分布不均等问题,扩大计算机网络的应用范围,结合局域网(Local Area Network,LAN)环境研究计算机网络安全技术的有效应用。由于局域网是互联网的重要组成部分之一,要想保证计算机网络的安全应当加强对安全技术、数据加密技术等技术的应用。基于此,提出了一种基于局域网环境的网络安全体系设计,以期为局域网中的计算机网络安全发展提供相应的参考。
文摘在互联网时代的宏观背景下,需要了解基于IP无线接入网(IP Radio Access Network,IPRAN)的主要作用。在本地网组网技术模式研究中,可以利用分组传输的数据值,通过设备实现基站业务回传和专线业务综合接入。IPRAN有极高的便捷性和兼容性,5G综合业务接入网IPRAN是未来的重要发展趋势,具有高品质、多点化服务特征。在承载需求上,从长期演进(Long Term Evolution,LTE)角度出发,依托区域骨干网对IPRAN组网各设备的构建和组网需求进行分析,实现综合业务接入网IPRAN的本地网组网技术模式的规划完善。
文摘由于无线网络主要在开放的空间环境内展开数据信息传输,而不是固定在物理线缆上,存在一定的安全隐患。因此,必须要优化落实对无线网络的安全防护。文章强调了无线局域网(Wireless Local Area Network,WLAN)安全防护的必要性,并对恶意攻击、非法用户入侵、重传攻击等影响计算机无线网络安全的主要因素进行了分析。在此基础上,从无线与有线一体化关联分析技术、无线网络安全保障机制、WLAN安全技术这几方面入手,着重阐述了基于WLAN的网络安全防护技术的具体应用,以营造更为安全的WLAN无线网络运行环境。
