随着位置感知技术的发展,室内定位的需求变得日益强烈。目前室内定位技术在线性环境下的应用较少,本文针对线性不稳定环境下定位耗时的问题,提出了短时路径记忆辅助的加权K最近邻算法SPM-WKNN(weighted Knearest neighbor of short time...随着位置感知技术的发展,室内定位的需求变得日益强烈。目前室内定位技术在线性环境下的应用较少,本文针对线性不稳定环境下定位耗时的问题,提出了短时路径记忆辅助的加权K最近邻算法SPM-WKNN(weighted Knearest neighbor of short time path memory)来提高定位效率。针对无线访问接入点(AP-access point)变化大的问题,本文提出了基于无线AP相关系数的接入点分簇机制,减小无线AP变化所带来的影响,提高定位精度。通过理论分析及仿真表明本文提出的SPM-WKNN算法和接入点分簇机制相对于原有算法在线性不稳定环境下可以有效缩短定位时间,提高定位精度。展开更多
车联网(Internet of Vehicles,Io V)被认为是物联网中最有可能率先突破应用的一个重要分支,成为目前研究的重点和热点.其中,车辆节点的定位和位置感知技术是车联网的技术核心,不仅关系到车辆行驶过程中的安全,而且影响着车联网的发展前...车联网(Internet of Vehicles,Io V)被认为是物联网中最有可能率先突破应用的一个重要分支,成为目前研究的重点和热点.其中,车辆节点的定位和位置感知技术是车联网的技术核心,不仅关系到车辆行驶过程中的安全,而且影响着车联网的发展前景.首先,提出了车联网定位和位置感知的评价标准,介绍了无线定位测距技术的实现原理和方法.在此基础上,重点阐述了车联网的定位和位置感知技术,讨论了相关算法以及在车联网中的应用特点.最后,在综合分析了现有研究成果的同时,对未来的研究方向进行了展望.展开更多
Quality-of-Service （QoS） describes the non-functional characteristics of Web services. As such, the QoS is a critical parameter in service selection, composition and fault tolerance, and must be accurately determine...Quality-of-Service （QoS） describes the non-functional characteristics of Web services. As such, the QoS is a critical parameter in service selection, composition and fault tolerance, and must be accurately determined by some type of QoS prediction method. However, with the dramatic increase in the number of Web services, the prediction failure caused by data sparseness has become a critical challenge. A new ＇hybrid user-location-aware prediction based on weighted Adamic-Adar （WAA）＇ （HUWAA） was proposed. The implicit neighbor search was optimized by incorporating location factors. Meanwhile, the ability of the improved algorithms to solve the data sparsity problem was validated in experiments on public real world datasets. The new algorithm outperforms the existing of item-based pearson correlation coefficient （IPCC）, user-based pearson correlation coefficient （UPCC） and Web service recommender system （WSRec） algorithms.展开更多
It becomes challenging in order to represent, discover and exchange location information in a ubiquitous environment due to dynamic movement and interaction between mobile nodes inside. In this paper, a new method is ...It becomes challenging in order to represent, discover and exchange location information in a ubiquitous environment due to dynamic movement and interaction between mobile nodes inside. In this paper, a new method is presented in order to make location information context-aware so that organizing the format of location information and maintaining the communication between direct connected nodes in a ubiquitous environment is enabled. The structure of a contextual location information repository and a context information communication protocol is manipulated to implement the proposed features. According to the simulation results in network simulator version2 （NS2）, the new method has depicted good discovery success ~nd consumed efficient service discovery bandwidth. Other network traffic, i.e. transmission control protocol, （TCP） has been simulated in the scenarios but the new location-aware method has shown its robustness with continuous context discovery process.展开更多
A user’s trajectory can be maliciously monitored by adversaries when they share the positions in location-aware social networking applications which require users to update their own locations continuously. An advers...A user’s trajectory can be maliciously monitored by adversaries when they share the positions in location-aware social networking applications which require users to update their own locations continuously. An adversary infers user’s locations from the trajectories, and gleans user’s private information through them via location-aware social networking applications and public available geographic data. In this paper, we propose a user proprietary obfuscate system to suit situations for position sharing and location privacy preserving in location-aware social network. Users transform the public available geographic data into personal obfuscate region maps with pre-defined profile to prevent the location leaking in stationary status. Our obfuscation with size restricted regions method tunes user’s transformed locations fitting into natural movement and prevents unreasonable snapshot locations been recorded in the trajectory.展开更多
This paper gives an overall introduction to the basic concept of LAC(location-aware computing) and its development status, puts forward an integrated location-aware computing architecture which is useful for designing...This paper gives an overall introduction to the basic concept of LAC(location-aware computing) and its development status, puts forward an integrated location-aware computing architecture which is useful for designing the reasonable logical model of LBS(location-based service). Finally, a brief introduction is conducted on a LAC experimental prototype, which acts as a mobile urban tourism assistant.展开更多
Indexing techniques have been developed for wireless data broadcast environments, in order to conserve the scarce power resources of the mobile clients. However, the use of interleaved index segments in a broadcast cy...Indexing techniques have been developed for wireless data broadcast environments, in order to conserve the scarce power resources of the mobile clients. However, the use of interleaved index segments in a broadcast cycle increases the average access latency for the clients. In this paper, the broadcast-based spatial query processing methods （BBS） are presented for the location-based services. In the BBS, broadcasted data objects are sorted sequentially based on their locations, and the server broadcasts the location dependent data along with an index segment. Then, a sequential prefetehing and caching scheme is designed to reduce the query response time. The performance of this scheme is investigated in relation to various environmental variables, such as the distributions of the data objects, the average speed of the clients and the size of the service area.展开更多
文摘随着位置感知技术的发展,室内定位的需求变得日益强烈。目前室内定位技术在线性环境下的应用较少,本文针对线性不稳定环境下定位耗时的问题,提出了短时路径记忆辅助的加权K最近邻算法SPM-WKNN(weighted Knearest neighbor of short time path memory)来提高定位效率。针对无线访问接入点(AP-access point)变化大的问题,本文提出了基于无线AP相关系数的接入点分簇机制,减小无线AP变化所带来的影响,提高定位精度。通过理论分析及仿真表明本文提出的SPM-WKNN算法和接入点分簇机制相对于原有算法在线性不稳定环境下可以有效缩短定位时间,提高定位精度。
文摘车联网(Internet of Vehicles,Io V)被认为是物联网中最有可能率先突破应用的一个重要分支,成为目前研究的重点和热点.其中,车辆节点的定位和位置感知技术是车联网的技术核心,不仅关系到车辆行驶过程中的安全,而且影响着车联网的发展前景.首先,提出了车联网定位和位置感知的评价标准,介绍了无线定位测距技术的实现原理和方法.在此基础上,重点阐述了车联网的定位和位置感知技术,讨论了相关算法以及在车联网中的应用特点.最后,在综合分析了现有研究成果的同时,对未来的研究方向进行了展望.
基金supported by the National Key project of Scientific and Technical Supporting Programs of China (2013BAH10F01, 2013BAH07F02, 2014BAH26F02)the Research Fund for the Doctoral Program of Higher Education (20110005120007)+2 种基金Beijing Higher Education Young Elite Teacher Project (YETP0445)the Co-construction Program with Beijing Municipal Commission of EducationEngineering Research Center of Information Networks,Ministry of Education
文摘Quality-of-Service （QoS） describes the non-functional characteristics of Web services. As such, the QoS is a critical parameter in service selection, composition and fault tolerance, and must be accurately determined by some type of QoS prediction method. However, with the dramatic increase in the number of Web services, the prediction failure caused by data sparseness has become a critical challenge. A new ＇hybrid user-location-aware prediction based on weighted Adamic-Adar （WAA）＇ （HUWAA） was proposed. The implicit neighbor search was optimized by incorporating location factors. Meanwhile, the ability of the improved algorithms to solve the data sparsity problem was validated in experiments on public real world datasets. The new algorithm outperforms the existing of item-based pearson correlation coefficient （IPCC）, user-based pearson correlation coefficient （UPCC） and Web service recommender system （WSRec） algorithms.
基金supported by the Project of the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Project of the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Nanjing(S7610014001)
文摘It becomes challenging in order to represent, discover and exchange location information in a ubiquitous environment due to dynamic movement and interaction between mobile nodes inside. In this paper, a new method is presented in order to make location information context-aware so that organizing the format of location information and maintaining the communication between direct connected nodes in a ubiquitous environment is enabled. The structure of a contextual location information repository and a context information communication protocol is manipulated to implement the proposed features. According to the simulation results in network simulator version2 （NS2）, the new method has depicted good discovery success ~nd consumed efficient service discovery bandwidth. Other network traffic, i.e. transmission control protocol, （TCP） has been simulated in the scenarios but the new location-aware method has shown its robustness with continuous context discovery process.
文摘A user’s trajectory can be maliciously monitored by adversaries when they share the positions in location-aware social networking applications which require users to update their own locations continuously. An adversary infers user’s locations from the trajectories, and gleans user’s private information through them via location-aware social networking applications and public available geographic data. In this paper, we propose a user proprietary obfuscate system to suit situations for position sharing and location privacy preserving in location-aware social network. Users transform the public available geographic data into personal obfuscate region maps with pre-defined profile to prevent the location leaking in stationary status. Our obfuscation with size restricted regions method tunes user’s transformed locations fitting into natural movement and prevents unreasonable snapshot locations been recorded in the trajectory.
文摘This paper gives an overall introduction to the basic concept of LAC(location-aware computing) and its development status, puts forward an integrated location-aware computing architecture which is useful for designing the reasonable logical model of LBS(location-based service). Finally, a brief introduction is conducted on a LAC experimental prototype, which acts as a mobile urban tourism assistant.
文摘Indexing techniques have been developed for wireless data broadcast environments, in order to conserve the scarce power resources of the mobile clients. However, the use of interleaved index segments in a broadcast cycle increases the average access latency for the clients. In this paper, the broadcast-based spatial query processing methods （BBS） are presented for the location-based services. In the BBS, broadcasted data objects are sorted sequentially based on their locations, and the server broadcasts the location dependent data along with an index segment. Then, a sequential prefetehing and caching scheme is designed to reduce the query response time. The performance of this scheme is investigated in relation to various environmental variables, such as the distributions of the data objects, the average speed of the clients and the size of the service area.
