In opportunistic networks, most existing buffer management policies including scheduling and passive dropping policies are mainly for routing protocols. In this paper, we proposed a Utility-based Buffer Management str...In opportunistic networks, most existing buffer management policies including scheduling and passive dropping policies are mainly for routing protocols. In this paper, we proposed a Utility-based Buffer Management strategy(UBM) for data dissemination in opportunistic networks. In UBM, we first design a method of computing the utility values of caching messages according to the interest of nodes and the delivery probability of messages, and then propose an overall buffer management policy based on the utility. UBM driven by receivers completely implements not only caching policies, passive and proactive dropping policies, but also scheduling policies of senders. Simulation results show that, compared with some classical dropping strategies, UBM can obtain higher delivery ratio and lower delay latency by using smaller network cost.展开更多
HashQuery,a Hash-area-based data dissemination protocol,was designed in wireless sensor networks. Using a Hash function which uses time as the key,both mobile sinks and sensors can determine the same Hash area. The se...HashQuery,a Hash-area-based data dissemination protocol,was designed in wireless sensor networks. Using a Hash function which uses time as the key,both mobile sinks and sensors can determine the same Hash area. The sensors can send the information about the events that they monitor to the Hash area and the mobile sinks need only to query that area instead of flooding among the whole network,and thus much energy can be saved. In addition,the location of the Hash area changes over time so as to balance the energy consumption in the whole network. Theoretical analysis shows that the proposed protocol can be energy-efficient and simulation studies further show that when there are 5 sources and 5 sinks in the network,it can save at least 50% energy compared with the existing two-tier data dissemination(TTDD) protocol,especially in large-scale wireless sensor networks.展开更多
Data dissemination is an important application in vehicular networks. We observe that messages in vehicular networks are usually subject to both time and space constraints, and therefore should be disseminated during ...Data dissemination is an important application in vehicular networks. We observe that messages in vehicular networks are usually subject to both time and space constraints, and therefore should be disseminated during a specified duration and within a specific coverage. Since vehicles are moving in and out of a region, dis-semination of a message should be repeated to achieve reliability. However, the reliable dissemination for some messages might be at the cost of unreliable or even no chance of dissemination for other messages, which raises tradeoffs between reliability and fairness. In this paper, we study the scheduling of data dis-semination in vehicular networks with mesh infrastructure. Firstly, we propose performance metrics for both reliability and fairness. Factors on both the time and space dimensions are incorporated in the reliability met-ric and the fairness in both network-wide and Mesh Roadside Unit-wise (MRU-wise) senses are considered in the fairness metric. Secondly, we propose several scheduling algorithms: one reliability-oriented algorithm, one fairness-oriented algorithm and three hybrid schemes. Finally, we perform extensive evaluation work to quantitatively analyze different scheduling algorithms. Our evaluation results show that 1) hybrid schemes outperform reliability-oriented and fairness-oriented algorithms in the sense of overall efficiency and 2) dif-ferent algorithms have quite different characteristics on reliability and fairness.展开更多
Unmanned aerial vehicles(UAVs) are increasingly considered in safe autonomous navigation systems to explore unknown environments where UAVs are equipped with multiple sensors to perceive the surroundings. However, how...Unmanned aerial vehicles(UAVs) are increasingly considered in safe autonomous navigation systems to explore unknown environments where UAVs are equipped with multiple sensors to perceive the surroundings. However, how to achieve UAVenabled data dissemination and also ensure safe navigation synchronously is a new challenge. In this paper, our goal is minimizing the whole weighted sum of the UAV’s task completion time while satisfying the data transmission task requirement and the UAV’s feasible flight region constraints. However, it is unable to be solved via standard optimization methods mainly on account of lacking a tractable and accurate system model in practice. To overcome this tough issue,we propose a new solution approach by utilizing the most advanced dueling double deep Q network(dueling DDQN) with multi-step learning. Specifically, to improve the algorithm, the extra labels are added to the primitive states. Simulation results indicate the validity and performance superiority of the proposed algorithm under different data thresholds compared with two other benchmarks.展开更多
Extensive investigation has been performed in location-centric or geocast routing protocols for reliable and efficient dissemination of information in Vehicular Adhoc Networks （VANETs）. Various location-centric rout...Extensive investigation has been performed in location-centric or geocast routing protocols for reliable and efficient dissemination of information in Vehicular Adhoc Networks （VANETs）. Various location-centric routing protocols have been suggested in literature for road safety ITS applications considering urban and highway traffic environment. This paper characterizes vehicular environments based on real traffic data and investigates the evolution of location-centric data dissemination. The current study is carded out with three main objectives： （i） to analyze the impact of dynamic traffic environment on the design of data dissemination techniques, （ii） to characterize location-centric data dissemination in terms of functional and qualitative behavior of protocols, properties, and strengths and weaknesses, and （iii） to find some future research directions in information dissemination based on location. Vehicular traffic environments have been classified into three categories based on physical characteristics such as speed, inter-vehicular distance, neighborhood stability, traffic volume, etc. Real traffic data is considered to analyze on-road traffic environments based on the measurement of physical parameters and weather conditions. Design issues are identified in incorporating physical parameters and weather conditions into data dissemination. Functional and qualitative characteristics of location-centric techniques are explored considering urban and highway environments. Comparative analysis of location-centric techniques is carded out for both urban and highway environments individually based on some unique and common characteristics of the environments. Finally, some future research directions are identified in the area based on the detailed investigation of traffic environments and location-centric data dissemination techniques.展开更多
Connectivity and data dissemination in vehicular ad hoc networks(VANETs)have recently received considerable attention.Due to the unique characteristics of VANETs,the network connectivity is poor and reliable transmiss...Connectivity and data dissemination in vehicular ad hoc networks(VANETs)have recently received considerable attention.Due to the unique characteristics of VANETs,the network connectivity is poor and reliable transmission in VANETs is hard to achieve.In this paper,we analyze the connectivity of randomly deployed vehicles on a road in VANETs and show the relation among the connectivity,the vehicle density and the communication radius.The reliable data dissemination scheme based on assisted nodes is studied.The simulation results show our novel scheme increases the network performance in terms of data dissemination rate.展开更多
Data Center Networks （DCNs） are the fundamental infrastructure for cloud computing. Driven by the massive parallel computing tasks in cloud computing, one-to-many data dissemination becomes one of the most important...Data Center Networks （DCNs） are the fundamental infrastructure for cloud computing. Driven by the massive parallel computing tasks in cloud computing, one-to-many data dissemination becomes one of the most important traffic patterns in DCNs. Many architectures and protocols are proposed to meet this demand. However, these proposals either require complicated configurations on switches and servers, or cannot deliver an optimal performance. In this paper, we propose the peer-assisted data dissemination for DCNs. This approach utilizes the rich physical connections with high bandwidths and mutli-path connections, to facilitate efficient one-to-many data dissemination. We prove that an optimal P2P data dissemination schedule exists for FatTree, a specially- designed DCN architecture. We then present a theoretical analysis of this algorithm in the general multi-rooted tree topology, a widely-used DCN architecture. Additionally, we explore the performance of an intuitive line structure for data dissemination. Our analysis and experimental results prove that this simple structure is able to produce a comparable performance to the optimal algorithm. Since DCN applications heavily rely on virtualization to achieve optimal resource sharing, we present a general implementation method for the proposed algorithms, which aims to mitigate the impact of the potentially-high churn rate of the virtual machines.展开更多
Wireless sensor networks （WSNs） have been applied in a variety of application areas. Most WSN systems, once deployed, are intended to operate unattended for a long period. During the lifetime, it is necessary to fix...Wireless sensor networks （WSNs） have been applied in a variety of application areas. Most WSN systems, once deployed, are intended to operate unattended for a long period. During the lifetime, it is necessary to fix bugs, reconfigure system parameters, and upgrade the software in order to achieve reliable system performance. However, manually collecting all nodes back and reconfiguring through serial connections with computer is infeasible since it is labor-intensive and inconvenient due to the harsh deploying environments. Hence, data dissemination over multi-hop is desired to facilitate such tasks. This survey discusses the requirements and challenges of data dissemination in WSNs, reviews existing work, introduces some relevant techniques, presents the metrics of the performance and comparisons of the state-of-the-art work, and finally suggests the possible future directions in data dissemination studies. This survey elaborates and compares existing approaches of two categories： structure-less schemes and structure-based schemes, classified by whether or not the network structure information is used during the disseminating process. In existing literatures, different categories have definite boundary and limited analysis on the trade-off between different categories. Besides, there is no survey that discusses the emerging techniques such as Constructive Interference （CI） while these techniques have the chance to change the framework of data dissemination. In a word, even though many efforts have been made, data dissemination in WSNs still needs some more work to embrace the new techniques and improve the efficiency and practicability further.展开更多
Vehicular Adhoc Networks(VANETs)enable vehicles to act as mobile nodes that can fetch,share,and disseminate information about vehicle safety,emergency events,warning messages,and passenger infotainment.However,the con...Vehicular Adhoc Networks(VANETs)enable vehicles to act as mobile nodes that can fetch,share,and disseminate information about vehicle safety,emergency events,warning messages,and passenger infotainment.However,the continuous dissemination of information fromvehicles and their one-hop neighbor nodes,Road Side Units(RSUs),and VANET infrastructures can lead to performance degradation of VANETs in the existing hostcentric IP-based network.Therefore,Information Centric Networks(ICN)are being explored as an alternative architecture for vehicular communication to achieve robust content distribution in highly mobile,dynamic,and errorprone domains.In ICN-based Vehicular-IoT networks,consumer mobility is implicitly supported,but producer mobility may result in redundant data transmission and caching inefficiency at intermediate vehicular nodes.This paper proposes an efficient redundant transmission control algorithm based on network coding to reduce data redundancy and accelerate the efficiency of information dissemination.The proposed protocol,called Network Cording Multiple Solutions Scheduling(NCMSS),is receiver-driven collaborative scheduling between requesters and information sources that uses a global parameter expectation deadline to effectively manage the transmission of encoded data packets and control the selection of information sources.Experimental results for the proposed NCMSS protocol is demonstrated to analyze the performance of ICN-vehicular-IoT networks in terms of caching,data retrieval delay,and end-to-end application throughput.The end-to-end throughput in proposed NCMSS is 22%higher(for 1024 byte data)than existing solutions whereas delay in NCMSS is reduced by 5%in comparison with existing solutions.展开更多
On-path caching is the prominent module in Content-Centric Networking(CCN),equipped with the capability to handle the demands of future networks such as the Internet of Things(IoT)and vehicular networks.The main focus...On-path caching is the prominent module in Content-Centric Networking(CCN),equipped with the capability to handle the demands of future networks such as the Internet of Things(IoT)and vehicular networks.The main focus of the CCN caching module is data dissemination within the network.Most of the existing strategies of in-network caching in CCN store the content at the maximumnumber of routers along the downloading path.Consequently,content redundancy in the network increases significantly,whereas the cache hit ratio and network performance decrease due to the unnecessary utilization of limited cache storage.Moreover,content redundancy adversely affects the cache resources,hit ratio,latency,bandwidth utilization,and server load.We proposed an in-network caching placement strategy named Coupling Parameters to Optimize Content Placement(COCP)to address the content redundancy and associated problems.The novelty of the technique lies in its capability tominimize content redundancy by creating a balanced cache space along the routing path by considering request rate,distance,and available cache space.The proposed approach minimizes the content redundancy and content dissemination within the network by using appropriate locations while increasing the cache hit ratio and network performance.The COCP is implemented in the simulator(Icarus)to evaluate its performance in terms of the cache hit ratio,path stretch,latency,and link load.Extensive experiments have been conducted to evaluate the proposed COCP strategy.The proposed COCP technique has been compared with the existing state-of-theart techniques,namely,Leave Copy Everywhere(LCE),Leave Copy Down(LCD),ProbCache,Cache Less forMore(CL4M),and opt-Cache.The results obtained with different cache sizes and popularities show that our proposed caching strategy can achieve up to 91.46%more cache hits,19.71%reduced latency,35.43%improved path stretch and 38.14%decreased link load.These results confirm that the proposed COCP strategy has the potential capability to handle the demands of future networks such as the Internet of Things(IoT)and vehicular networks.展开更多
Purpose-The purpose of this paper is to introduce a new data dissemination model in order to improve the performance of transmission in VANET.It proposes a protocol named Epidemic and Transmission-Segmentbased Geograp...Purpose-The purpose of this paper is to introduce a new data dissemination model in order to improve the performance of transmission in VANET.It proposes a protocol named Epidemic and Transmission-Segmentbased Geographic Routing(ETSGR)and outlining the issues due to high mobility of nodes and uncertain physical topologies in the network.The proposed ETSGR is mainly used to analyze the vehicle state,direction,distance,traffic density and link quality of the network.Design/methodology/approach-This research work based on ETSGR protocol mainly uses epidemic algorithmin order to find the vehicle state based on susceptible,infected and recovered(SIR)model.Furthermore,the vehicle position and finding the head node in the network is utilized using the transmission segment protocol based on geographic routing and analyses each node to formthe segments and find the destination to transmit the data in timely manner.Findings-The paper provides the enhancement of the performance based on some metrics such as end-to-end delaythat obtained 0.62%,data throughput as 32.3%,packetdelivery ratio as 67%and one-hop communicationas 13%.The proposed ETSGR protocolanalyzes the state of the vehiclecorrectly and each node segmented to transmit the data with the timely manner and obtaining reliable performanceeven with highmobility of nodes in the network.Research limitations/implications-The proposed ETSGR protocol may have some limitation when considering the timing which should improve even in increasing many number of vehicles and different road segments.Practical implications-This paper includes some suggestions for the practical deployment of the approach in which a real-time traffic analysis can be evaluated for taking prior actions during an emergency situation and proper dissemination of data in timely manner can help utilize the guidance of proper planning of roads.Originality/value-This research fulfills an enhanced protocol to improve the performance of data dissemination.展开更多
Authorized content is a type of content that can be generated only by a certain Content Provider(CP).The content copies delivered to a user may bring rewards to the CP if the content is adopted by the user. The overal...Authorized content is a type of content that can be generated only by a certain Content Provider(CP).The content copies delivered to a user may bring rewards to the CP if the content is adopted by the user. The overall reward obtained by the CP depends on the user's degree of interest in the content and the user's role in disseminating the content copies. Thus, to maximize the reward, the content provider is motivated to disseminate the authorized content to the most interested users. In this paper, we study how to effectively disseminate the authorized content in Interest-centric Opportunistic Social Networks(IOSNs) such that the reward is maximized.We first derive Social Connection Pattern(SCP) data to handle the challenging opportunistic connections in IOSNs and statistically analyze the interest distribution of the users contacted or connected. The SCP is used to predict the interests of possible contactors and connectors. Then, we propose our SCP-based Dissemination(SCPD)algorithm to calculate the optimum number of content copies to disseminate when two users meet. Our dataset based simulation shows that our SCPD algorithm is effective and efficient to disseminate the authorized content in IOSNs.展开更多
提出了一种DTN多源多宿网络的数据编码分发机制(Data Dissemination Mechanism with Network Coding Based on Ant Colony Algorithm,DDM-NC).在发布/订阅机制的基础上,通过对主题数据的编码运算和传输,充分利用网络容量进行数据多播,...提出了一种DTN多源多宿网络的数据编码分发机制(Data Dissemination Mechanism with Network Coding Based on Ant Colony Algorithm,DDM-NC).在发布/订阅机制的基础上,通过对主题数据的编码运算和传输,充分利用网络容量进行数据多播,使得数据传输具有更好的安全性和传输效率;同时,针对编码包洪泛传输过程中信息冗余大,无效投递较多等问题,设计了基于蚁群算法的编码包路由策略,引导编码包向信宿聚集,降低编码投递过程中的数据冗余,减少投递延迟.仿真实验表明,相比传统的DTN传染病路由策略和随机网络编码传输方法,DDM-NC方法有更好的数据投递性能.展开更多
提出了一种面向发布/订阅系统基于车辆移动分布感知的事件分发策略MDA(mobile distribution-aware data dissemination).基于车流的自组织性及自稳性的特点,建立VANET(vehicular ad hoc network)下的发布/订阅模型,通过计算车辆与移动...提出了一种面向发布/订阅系统基于车辆移动分布感知的事件分发策略MDA(mobile distribution-aware data dissemination).基于车流的自组织性及自稳性的特点,建立VANET(vehicular ad hoc network)下的发布/订阅模型,通过计算车辆与移动订阅者的相遇概率,预测订阅者的移动分布,并以此为依据实时部署和调度广播令牌在网络中的转发,从而有效地控制事件代理的分布,保证了数据传递的有效性.与已有相关研究相比,MDA采用的启发式算法,能够使事件代理的分布更好地适应网络环境的动态变化.此外,MDA采用了一种基于概率预测密度的令牌控制算法,通过实时地调整令牌的数量,进而控制事件代理的数量,降低了整个网络的负载.模拟实验结果表明,与现有的几种消息分发算法相比,MDA能以较低的网络负载和传输延迟获得较高的数据传输成功率.展开更多
车载网络通过移动车辆的无线通信装置实现数据共享,是未来智能交通系统中的重要技术。传统的车载网络数据分发大多基于泛洪的传染扩散方法,其虽能适应网络的拓扑动态性,却无法达到高效和实用的目的。提出了一种适用于车载机会网络的自...车载网络通过移动车辆的无线通信装置实现数据共享,是未来智能交通系统中的重要技术。传统的车载网络数据分发大多基于泛洪的传染扩散方法,其虽能适应网络的拓扑动态性,却无法达到高效和实用的目的。提出了一种适用于车载机会网络的自适应拷贝数据分发算法ACS(Adaptive Copy and Spreading),它通过车辆移动参数(如方向、速度)动态计算所需分发数据的拷贝数并确定消息删除策略。仿真结果表明,ACS算法相比随机选择分发算法和传染扩散算法降低了对网络资源的需求,适用于多种应用场景。展开更多
基金supported by the National Natural Science Fund of China under Grant No. 61472097the Education Ministry Doctoral Research Foundation of China (20132304110017)the International Exchange Program of Harbin Engineering University for Innovation-oriented Talents Cultivation
文摘In opportunistic networks, most existing buffer management policies including scheduling and passive dropping policies are mainly for routing protocols. In this paper, we proposed a Utility-based Buffer Management strategy(UBM) for data dissemination in opportunistic networks. In UBM, we first design a method of computing the utility values of caching messages according to the interest of nodes and the delivery probability of messages, and then propose an overall buffer management policy based on the utility. UBM driven by receivers completely implements not only caching policies, passive and proactive dropping policies, but also scheduling policies of senders. Simulation results show that, compared with some classical dropping strategies, UBM can obtain higher delivery ratio and lower delay latency by using smaller network cost.
基金Project(07JJ1010) supported by Hunan Provincial Natural Science Foundation of ChinaProjects(2006AA01Z202, 2006AA01Z199) supported by the National High-Tech Research and Development Program of China+2 种基金Project(7002102) supported by the City University of Hong Kong, Strategic Research Grant (SRG)Project(IRT-0661) supported by the Program for Changjiang Scholars and Innovative Research Team in UniversityProject(NCET-06-0686) supported by the Program for New Century Excellent Talents in University
文摘HashQuery,a Hash-area-based data dissemination protocol,was designed in wireless sensor networks. Using a Hash function which uses time as the key,both mobile sinks and sensors can determine the same Hash area. The sensors can send the information about the events that they monitor to the Hash area and the mobile sinks need only to query that area instead of flooding among the whole network,and thus much energy can be saved. In addition,the location of the Hash area changes over time so as to balance the energy consumption in the whole network. Theoretical analysis shows that the proposed protocol can be energy-efficient and simulation studies further show that when there are 5 sources and 5 sinks in the network,it can save at least 50% energy compared with the existing two-tier data dissemination(TTDD) protocol,especially in large-scale wireless sensor networks.
文摘Data dissemination is an important application in vehicular networks. We observe that messages in vehicular networks are usually subject to both time and space constraints, and therefore should be disseminated during a specified duration and within a specific coverage. Since vehicles are moving in and out of a region, dis-semination of a message should be repeated to achieve reliability. However, the reliable dissemination for some messages might be at the cost of unreliable or even no chance of dissemination for other messages, which raises tradeoffs between reliability and fairness. In this paper, we study the scheduling of data dis-semination in vehicular networks with mesh infrastructure. Firstly, we propose performance metrics for both reliability and fairness. Factors on both the time and space dimensions are incorporated in the reliability met-ric and the fairness in both network-wide and Mesh Roadside Unit-wise (MRU-wise) senses are considered in the fairness metric. Secondly, we propose several scheduling algorithms: one reliability-oriented algorithm, one fairness-oriented algorithm and three hybrid schemes. Finally, we perform extensive evaluation work to quantitatively analyze different scheduling algorithms. Our evaluation results show that 1) hybrid schemes outperform reliability-oriented and fairness-oriented algorithms in the sense of overall efficiency and 2) dif-ferent algorithms have quite different characteristics on reliability and fairness.
基金supported by the National Natural Science Foundation of China (No. 61931011)。
文摘Unmanned aerial vehicles(UAVs) are increasingly considered in safe autonomous navigation systems to explore unknown environments where UAVs are equipped with multiple sensors to perceive the surroundings. However, how to achieve UAVenabled data dissemination and also ensure safe navigation synchronously is a new challenge. In this paper, our goal is minimizing the whole weighted sum of the UAV’s task completion time while satisfying the data transmission task requirement and the UAV’s feasible flight region constraints. However, it is unable to be solved via standard optimization methods mainly on account of lacking a tractable and accurate system model in practice. To overcome this tough issue,we propose a new solution approach by utilizing the most advanced dueling double deep Q network(dueling DDQN) with multi-step learning. Specifically, to improve the algorithm, the extra labels are added to the primitive states. Simulation results indicate the validity and performance superiority of the proposed algorithm under different data thresholds compared with two other benchmarks.
文摘Extensive investigation has been performed in location-centric or geocast routing protocols for reliable and efficient dissemination of information in Vehicular Adhoc Networks （VANETs）. Various location-centric routing protocols have been suggested in literature for road safety ITS applications considering urban and highway traffic environment. This paper characterizes vehicular environments based on real traffic data and investigates the evolution of location-centric data dissemination. The current study is carded out with three main objectives： （i） to analyze the impact of dynamic traffic environment on the design of data dissemination techniques, （ii） to characterize location-centric data dissemination in terms of functional and qualitative behavior of protocols, properties, and strengths and weaknesses, and （iii） to find some future research directions in information dissemination based on location. Vehicular traffic environments have been classified into three categories based on physical characteristics such as speed, inter-vehicular distance, neighborhood stability, traffic volume, etc. Real traffic data is considered to analyze on-road traffic environments based on the measurement of physical parameters and weather conditions. Design issues are identified in incorporating physical parameters and weather conditions into data dissemination. Functional and qualitative characteristics of location-centric techniques are explored considering urban and highway environments. Comparative analysis of location-centric techniques is carded out for both urban and highway environments individually based on some unique and common characteristics of the environments. Finally, some future research directions are identified in the area based on the detailed investigation of traffic environments and location-centric data dissemination techniques.
基金Shandong College Research Project of Science&Technology(NO.J12LN13)
文摘Connectivity and data dissemination in vehicular ad hoc networks(VANETs)have recently received considerable attention.Due to the unique characteristics of VANETs,the network connectivity is poor and reliable transmission in VANETs is hard to achieve.In this paper,we analyze the connectivity of randomly deployed vehicles on a road in VANETs and show the relation among the connectivity,the vehicle density and the communication radius.The reliable data dissemination scheme based on assisted nodes is studied.The simulation results show our novel scheme increases the network performance in terms of data dissemination rate.
基金supported in part by the Natural Science Foundation of USA(Nos.ECCS 1128209,CNS 10655444,CCF 1028167,CNS 0948184,and CCF 0830289)
文摘Data Center Networks （DCNs） are the fundamental infrastructure for cloud computing. Driven by the massive parallel computing tasks in cloud computing, one-to-many data dissemination becomes one of the most important traffic patterns in DCNs. Many architectures and protocols are proposed to meet this demand. However, these proposals either require complicated configurations on switches and servers, or cannot deliver an optimal performance. In this paper, we propose the peer-assisted data dissemination for DCNs. This approach utilizes the rich physical connections with high bandwidths and mutli-path connections, to facilitate efficient one-to-many data dissemination. We prove that an optimal P2P data dissemination schedule exists for FatTree, a specially- designed DCN architecture. We then present a theoretical analysis of this algorithm in the general multi-rooted tree topology, a widely-used DCN architecture. Additionally, we explore the performance of an intuitive line structure for data dissemination. Our analysis and experimental results prove that this simple structure is able to produce a comparable performance to the optimal algorithm. Since DCN applications heavily rely on virtualization to achieve optimal resource sharing, we present a general implementation method for the proposed algorithms, which aims to mitigate the impact of the potentially-high churn rate of the virtual machines.
基金supported by the National Natural Science Foundation of China under Grant No.61170220
文摘Wireless sensor networks （WSNs） have been applied in a variety of application areas. Most WSN systems, once deployed, are intended to operate unattended for a long period. During the lifetime, it is necessary to fix bugs, reconfigure system parameters, and upgrade the software in order to achieve reliable system performance. However, manually collecting all nodes back and reconfiguring through serial connections with computer is infeasible since it is labor-intensive and inconvenient due to the harsh deploying environments. Hence, data dissemination over multi-hop is desired to facilitate such tasks. This survey discusses the requirements and challenges of data dissemination in WSNs, reviews existing work, introduces some relevant techniques, presents the metrics of the performance and comparisons of the state-of-the-art work, and finally suggests the possible future directions in data dissemination studies. This survey elaborates and compares existing approaches of two categories： structure-less schemes and structure-based schemes, classified by whether or not the network structure information is used during the disseminating process. In existing literatures, different categories have definite boundary and limited analysis on the trade-off between different categories. Besides, there is no survey that discusses the emerging techniques such as Constructive Interference （CI） while these techniques have the chance to change the framework of data dissemination. In a word, even though many efforts have been made, data dissemination in WSNs still needs some more work to embrace the new techniques and improve the efficiency and practicability further.
基金funded by Wenzhou Kean University under the IRSP Program“Hop by Hop Resource Reservation based Scheduling Function for Deterministic IoT networks”.
文摘Vehicular Adhoc Networks(VANETs)enable vehicles to act as mobile nodes that can fetch,share,and disseminate information about vehicle safety,emergency events,warning messages,and passenger infotainment.However,the continuous dissemination of information fromvehicles and their one-hop neighbor nodes,Road Side Units(RSUs),and VANET infrastructures can lead to performance degradation of VANETs in the existing hostcentric IP-based network.Therefore,Information Centric Networks(ICN)are being explored as an alternative architecture for vehicular communication to achieve robust content distribution in highly mobile,dynamic,and errorprone domains.In ICN-based Vehicular-IoT networks,consumer mobility is implicitly supported,but producer mobility may result in redundant data transmission and caching inefficiency at intermediate vehicular nodes.This paper proposes an efficient redundant transmission control algorithm based on network coding to reduce data redundancy and accelerate the efficiency of information dissemination.The proposed protocol,called Network Cording Multiple Solutions Scheduling(NCMSS),is receiver-driven collaborative scheduling between requesters and information sources that uses a global parameter expectation deadline to effectively manage the transmission of encoded data packets and control the selection of information sources.Experimental results for the proposed NCMSS protocol is demonstrated to analyze the performance of ICN-vehicular-IoT networks in terms of caching,data retrieval delay,and end-to-end application throughput.The end-to-end throughput in proposed NCMSS is 22%higher(for 1024 byte data)than existing solutions whereas delay in NCMSS is reduced by 5%in comparison with existing solutions.
基金This work was supported by Taif University Researchers Supporting Project Number(TURSP-2020/292),Taif University,Taif,Saudi Arabia。
文摘On-path caching is the prominent module in Content-Centric Networking(CCN),equipped with the capability to handle the demands of future networks such as the Internet of Things(IoT)and vehicular networks.The main focus of the CCN caching module is data dissemination within the network.Most of the existing strategies of in-network caching in CCN store the content at the maximumnumber of routers along the downloading path.Consequently,content redundancy in the network increases significantly,whereas the cache hit ratio and network performance decrease due to the unnecessary utilization of limited cache storage.Moreover,content redundancy adversely affects the cache resources,hit ratio,latency,bandwidth utilization,and server load.We proposed an in-network caching placement strategy named Coupling Parameters to Optimize Content Placement(COCP)to address the content redundancy and associated problems.The novelty of the technique lies in its capability tominimize content redundancy by creating a balanced cache space along the routing path by considering request rate,distance,and available cache space.The proposed approach minimizes the content redundancy and content dissemination within the network by using appropriate locations while increasing the cache hit ratio and network performance.The COCP is implemented in the simulator(Icarus)to evaluate its performance in terms of the cache hit ratio,path stretch,latency,and link load.Extensive experiments have been conducted to evaluate the proposed COCP strategy.The proposed COCP technique has been compared with the existing state-of-theart techniques,namely,Leave Copy Everywhere(LCE),Leave Copy Down(LCD),ProbCache,Cache Less forMore(CL4M),and opt-Cache.The results obtained with different cache sizes and popularities show that our proposed caching strategy can achieve up to 91.46%more cache hits,19.71%reduced latency,35.43%improved path stretch and 38.14%decreased link load.These results confirm that the proposed COCP strategy has the potential capability to handle the demands of future networks such as the Internet of Things(IoT)and vehicular networks.
文摘Purpose-The purpose of this paper is to introduce a new data dissemination model in order to improve the performance of transmission in VANET.It proposes a protocol named Epidemic and Transmission-Segmentbased Geographic Routing(ETSGR)and outlining the issues due to high mobility of nodes and uncertain physical topologies in the network.The proposed ETSGR is mainly used to analyze the vehicle state,direction,distance,traffic density and link quality of the network.Design/methodology/approach-This research work based on ETSGR protocol mainly uses epidemic algorithmin order to find the vehicle state based on susceptible,infected and recovered(SIR)model.Furthermore,the vehicle position and finding the head node in the network is utilized using the transmission segment protocol based on geographic routing and analyses each node to formthe segments and find the destination to transmit the data in timely manner.Findings-The paper provides the enhancement of the performance based on some metrics such as end-to-end delaythat obtained 0.62%,data throughput as 32.3%,packetdelivery ratio as 67%and one-hop communicationas 13%.The proposed ETSGR protocolanalyzes the state of the vehiclecorrectly and each node segmented to transmit the data with the timely manner and obtaining reliable performanceeven with highmobility of nodes in the network.Research limitations/implications-The proposed ETSGR protocol may have some limitation when considering the timing which should improve even in increasing many number of vehicles and different road segments.Practical implications-This paper includes some suggestions for the practical deployment of the approach in which a real-time traffic analysis can be evaluated for taking prior actions during an emergency situation and proper dissemination of data in timely manner can help utilize the guidance of proper planning of roads.Originality/value-This research fulfills an enhanced protocol to improve the performance of data dissemination.
文摘Authorized content is a type of content that can be generated only by a certain Content Provider(CP).The content copies delivered to a user may bring rewards to the CP if the content is adopted by the user. The overall reward obtained by the CP depends on the user's degree of interest in the content and the user's role in disseminating the content copies. Thus, to maximize the reward, the content provider is motivated to disseminate the authorized content to the most interested users. In this paper, we study how to effectively disseminate the authorized content in Interest-centric Opportunistic Social Networks(IOSNs) such that the reward is maximized.We first derive Social Connection Pattern(SCP) data to handle the challenging opportunistic connections in IOSNs and statistically analyze the interest distribution of the users contacted or connected. The SCP is used to predict the interests of possible contactors and connectors. Then, we propose our SCP-based Dissemination(SCPD)algorithm to calculate the optimum number of content copies to disseminate when two users meet. Our dataset based simulation shows that our SCPD algorithm is effective and efficient to disseminate the authorized content in IOSNs.
基金Supported by the National High-Tech Research and Development Plan of China under Grant No.2006AA01Z206 (国家高技术研究发展计划(863))the National Key Project of Scientific and Technical Supporting Programs of China under Grant No.2006BAH02A03 (国家"十一五"科技支撑计划)
文摘提出了一种DTN多源多宿网络的数据编码分发机制(Data Dissemination Mechanism with Network Coding Based on Ant Colony Algorithm,DDM-NC).在发布/订阅机制的基础上,通过对主题数据的编码运算和传输,充分利用网络容量进行数据多播,使得数据传输具有更好的安全性和传输效率;同时,针对编码包洪泛传输过程中信息冗余大,无效投递较多等问题,设计了基于蚁群算法的编码包路由策略,引导编码包向信宿聚集,降低编码投递过程中的数据冗余,减少投递延迟.仿真实验表明,相比传统的DTN传染病路由策略和随机网络编码传输方法,DDM-NC方法有更好的数据投递性能.
文摘提出了一种面向发布/订阅系统基于车辆移动分布感知的事件分发策略MDA(mobile distribution-aware data dissemination).基于车流的自组织性及自稳性的特点,建立VANET(vehicular ad hoc network)下的发布/订阅模型,通过计算车辆与移动订阅者的相遇概率,预测订阅者的移动分布,并以此为依据实时部署和调度广播令牌在网络中的转发,从而有效地控制事件代理的分布,保证了数据传递的有效性.与已有相关研究相比,MDA采用的启发式算法,能够使事件代理的分布更好地适应网络环境的动态变化.此外,MDA采用了一种基于概率预测密度的令牌控制算法,通过实时地调整令牌的数量,进而控制事件代理的数量,降低了整个网络的负载.模拟实验结果表明,与现有的几种消息分发算法相比,MDA能以较低的网络负载和传输延迟获得较高的数据传输成功率.
文摘车载网络通过移动车辆的无线通信装置实现数据共享,是未来智能交通系统中的重要技术。传统的车载网络数据分发大多基于泛洪的传染扩散方法,其虽能适应网络的拓扑动态性,却无法达到高效和实用的目的。提出了一种适用于车载机会网络的自适应拷贝数据分发算法ACS(Adaptive Copy and Spreading),它通过车辆移动参数(如方向、速度)动态计算所需分发数据的拷贝数并确定消息删除策略。仿真结果表明,ACS算法相比随机选择分发算法和传染扩散算法降低了对网络资源的需求,适用于多种应用场景。
