RBFT:基于Raft集群的拜占庭容错共识机制

针对现有联盟链共识机制因可拓展性不足,无法在支持大规模网络的同时满足低时延、高吞吐量和安全性的问题,采用网络分片的思想,提出一种适用于联盟链的带有监督节点的两级共识机制——RBFT.首先对网络节点进行分组,组内采用改进的Raft机制进行共识,然后由每个组内选出的领导者组成网络委员会,网络委员会内部采用PBFT机制进行共...     

基于加权一致优化的宽带分布式协作压缩频谱感知算法

宽带分布式协作压缩频谱感知不仅降低过高的采样速率,而且改善在低信噪比环境下的频谱感知性能。为进一步提高频谱感知性能,提出一种基于加权一致优化的宽带分布式协作压缩频谱感知算法。该算法根据当前迭代重构出的频谱信号设定下一次迭代重构的权值,促使频谱信号上存在授权用户的子频段产生信号值,降低重构出错的可能性。仿真结果表明,该算法不仅能够增大频谱重构的准确性,而且能够降低感知过程的时间和通信开销,改善频谱感知性能。     

基于信誉积分的路况信息共享中共谋攻击节点检测方法

针对车联网中共谋节点可能协同发布虚假路况信息,导致路况信息共享过程中消息真实性无法保证的问题,提出了一种基于信誉积分的路况信息共享中共谋攻击节点检测方法.在路况信息聚合过程中,设计了恶意信息检测算法,能够检测到共谋节点发布的虚假消息,保证系统中传递消息的真实准确.安全性评估和实验表明,相比于现有方案,该方法对共谋节点的...     

Improving the reliability of Byzantine fault‐tolerant distributed software‐defined networks

This paper presents a method to improve the reliability and fault tolerance of distributed software‐defined networks. This method is called “BIRDSDN (Byzantine‐Resilient Improved Reliable Distributed Software‐Defined Networks).” In BIRDSDN, a group communication is implemented among the controllers of the whole clusters. This method can detect the crash failure and Byzantine failure of any controller and undertakes a fast detection and recovery scheme to select the controllers to take over the orphan switches. BIRDSDN takes into account the reliability of the nodes considering the failure probability of intracluster and intercluster links, topology, load, and latency. The numerical results show that this approach performs better than the other approaches regarding failure detection, recovery, latency, throughput, reliability, and packet loss.     

Mitigating spectrum sensing data falsification attack in ad hoc cognitive radio networks

In a cognitive radio ad hoc network, there is no central authority. Hence, distributed collaborative spectrum sensing (CSS) plays a major role in achieving an accurate spectrum sensing result. However, CSS is sensitive to spectrum sensing data falsification (SSDF) attack, in which a malicious user falsifies its local sensing report before disseminating it into the network. To capture such abnormal behavior of a node, we present an approach for detecting SSDF attack based on dissimilarity score. A secondary user (SU) computes the dissimilarity score of its neighbors from the messages received from its h‐hop neighbors. Further, we also present how the proposed scheme can be used on the sequence of sensing reports to detect and isolate the malicious SUs on the fly.     

分布式认知无线电网络中的主动频谱切换

主要研究分布式认知无线电网络中的频谱切换,并提出一种主动的频谱切换方案。认知用户通过感知结果与历史信息建立授权用户的活动模型,预测频谱的使用情况。在不对授权用户产生干扰的前提下,提前安排频谱切换。同时,采用基于蚁群任务分工算法的频谱选择方法,使得认知用户综合考虑通信参数,实现认知用户的按需切换,保证不间断的传输。仿真表明,提出的方案能够提前执行切换,并在较短的时间内完成业务量的传输,同时具备较高的灵活性,适用于分布式认知无线电网络。     

模拟人群信任和决策机制的协作频谱感知方法

通过模拟人群内部的信任和决策机制,针对多用户的频谱协作感知一致性问题,提出了一种分布式算法。该算法首先通过网络的历次协作过程预测出各感知用户的动态可信值,据此产生用户的相对可信值,并结合决策机制使得用户之间进行数据交互,随着数据的可信、迭代交互,所有用户状态将趋于一致,最后通过判定算法得出最终结果。算法充分考虑了实际环境中各用户频带感知能力的不平衡性,而且各次级用户只需要进行少量局部数据交换即可实现协作感知,与传统的OR-rule、1-out-of-N rule以及普通迭代法有较大区别。对3种数据篡改攻击进行了分析,并在预测算法的基础上提出了相应的安全策略。理论分析与仿真结果表明,新算法在准确性和安全性上均优于传统合作频谱感知算法,能显著提高频谱感知准确率,同时兼具较强的防攻击能力。     

Blockchain trading mechanism based on attached chain for the delay tolerant network

In order to deploy a blockchain on the non-continuous connectivity delay tolerant network,a blockchain trading mechanism was designed,which could run on this type of network.First,the identifier was introduced into the existing block structure and a block structure on the attached chain was presented,which could append the blocks generated during network disconnection.Then,the approaches including the block package,block mining and block consensus on the attached chain were proposed.Finally,a confirming consensus approach was presented to avoid block fraud in the process of appending the attached chain.Through theoretical proof and experimental analysis,the proposed mechanism can support blockchain trading in the delay tolerant network.     

基于互联网的温湿度分布式监控系统的实现

针对现有温湿度监控系统在检测点数较多的情况下存在的若干问题,以及监控系统不方便接入互联网的缺陷,提出并实现了一种基于互联网的温湿度分布式监控系统,进而提高了温湿度监控系统的可靠性、可用性和扩展性.     

区块链技术在物联网中应用研究

区块链技术在物联网中的应用在很大程度上缓解了数据隐私、网络安全等现象,为了拓展区块链技术的应用,需要相关人员重视技术研究.本文阐述了区块链技术概述、区块链技术在物联网中的应用、针对物联网的区块链底层技术研究以及区块链为物联网带来的诸多挑战,希望能够促进区块链技术的应用,从而创造更大的效益.     

Spatial spectrum approach for pilot spoofing attack detection in MIMO systems

In this study, a spatial spectrum method is proposed to cope with the pilot spoofing attack (PSA) problem by exploiting the of uplink–downlink channel reciprocity in time-division-duplex multiple-input multiple-output systems. First, the spoofing attack in the uplink stage is detected by a threshold derived from the predefined false alarm based on the estimated spatial spectrum. When the PSA occurs, the transmitter (That is Alice) can detect either one or two spatial spectrum peaks. Then, the legitimate user (That is Bob) and Eve are recognized in the downlink stage via the channel reciprocity property based on the difference between the spatial spectra if PSA occurs. This way, the presence of Eve and the direction of arrival of Eve and Bob can be identified at the transmitter end. Because noise is suppressed by a spatial spectrum, the detection performance is reliable even for low signal-noise ratios and a short training length. Consequently, Bob can use beamforming to transmit secure information during the data transmission stage. Theoretical analysis and numerical simulations are performed to evaluate the performance of the proposed scheme compared with conventional methods.     

A reputation-based RPL protocol to detect selective forwarding attack in Internet of Things

Internet of Things (IoT) is an internet of smart objects where smart objects communicate with each other. IoT objects are deployed in open medium with dynamic topology. Due lack of infrastructure and centralized management, IoT present serious vulnerabilities to security attacks. Therefore, security is an essential prerequisite for the real-world deployment of IoT. In this work, we propose reputation-based RPL protocol where reputation-based mechanism is embedded into RPL protocol to enhance its capabilities against selective forwarding attack. Reputation is calculated by evaluating data forwarding behavior of IoT node. Data forwarding behavior of IoT node is evaluated by the difference between monitored actual packet loss and estimated normal loss. Calculated reputation value is considered in parent selection. Simulation results show that the proposed approach can accurately detect and isolate selective forwarding attack with improving data delivery ratio of the IoT network.     

互联网环境下电子图书共享机制设计

互联网环境下信息资源共享机制研究正处于方兴未艾的阶段,网络上电子图书馆的出现从很大程度促进了图书资源的共享,但单靠一个组织或公司来收集提供电子图书共事服务,无论从图书数量还是服务能力来看,都是远远不够的.只有充分的利用互联网上众多PC上的电子图书资源和服务资源,才有可能实现电子图书资源真正意义上的全面共享.现提出一种基于层次且结构拓扑的互联网环境下电子图书共享机制来管理和组织这些分散的PC资源,使之相互协同组织其上的电子图书资源并提供电子图书发现服务.     

面向车联网异构节点的区块链高效一致性共识算法研究

车联网异构节点由于其性能差异大、具有移动性等原因会造成区块链共识算法交易吞吐率低、交易时延较大等问题,该文提出面向车联网异构节点的区块链高效一致性共识算法(ECCA)。首先,在ECCA中,考虑由验证节点、一般节点和恶意节点组成的车联网异构节点,提出一种信用等级机制,实现信用等级划分和3类异构节点的划分。其次,提出一种跨区下的节点身份变更机制,及时调整当前区域内的节点身份。最后,提出一种改进的一致性共识算法,满足车联网的时效性需求。仿真结果表明：ECCA算法降低性能较差的一般节点和恶意节点对区块共识效率的影响,提高交易吞吐量,降低平均交易时延和平均节点通信开销。     

Integration of Internet of Things and blockchain technology in healthcare domain: A systematic literature review

Healthcare is a vitally important field in the industry and evolving day by day in the aspect of technology, services, computing, and management. Its potential significance can be increased by incorporating Internet of Things (IoT) technology to make it smart in the aspect of automating activities, which is then further reformed in the healthcare domain with the help of blockchain technology. Blockchain technology provides many features to IoT-based healthcare domain applications such as restructuring by securing traditional practices, data management, data sharing, patient remote monitoring, and drug analysis. In this study, a systematic literature review has been carried out in which a total of 52 studies were selected to conduct systematic literature review from databases PubMed, IEEE Access, and Scopus; the study includes IoT technology and blockchain integration in healthcare domain-related application areas. This study also includes taxonomy that mentions the aspects and areas in healthcare domain incorporating the traditional system with the integration of IoT and blockchain to provide transparency, security, privacy, and immutability. This study also includes the incorporation of related sensors, platforms of blockchain, the objective focus of selected studies, and future directions by incorporating IoT and blockchain in healthcare domain. This study will help researchers who want to work with IoT and blockchain technology integration in healthcare domain.     

云计算分布式缓存技术及其在物联网中的应用

物联网是信息技术发展到一定阶段的产物,而云计算平台是物联网应用的基础。文章从当前云计算应用所面临的问题和缺陷出发,介绍了云计算分布式缓存的部署方式、功能架构及关键技术,并说明了分布式缓存高性能、高吞吐、高可靠性、高扩展性等优势和特性。文章解决了物联网应用普遍面临的数据可靠性、大容量内存共享、多模块数据一致保障、线性扩容等难题,为物联网平台云化架构的底层支撑奠定了基础。     

无线物联网中的频谱感知模型研究

In the last few years, the number of devices operating in wireless Internet of Things (IoT) has experienced tremendous growth. On the other hand, the growth results in spectrum scarcity. Cognitive Radio (CR) systems have been proposed to efficiently exploit the spectra that have been assigned but are underutilized. In this paper, a spectrum sensing model based on Markov chain is proposed to predict the spectrum hole for CR in wireless IoT. Theoretical analysis and simulation results have been evaluated that a Markov model with two-state or four-state works well enough in wireless IoT whereas a model with more states is not necessary for it is complex.     

认知电力物联网电视频谱感知方法

基于认知无线电(CR)技术的电力物联网(IOTIPS)通过频谱感知实现对空闲授权频段的接入,可以有效提高频谱利用率,由于电力物联网的通信环境复杂,载波频偏无法避免,提出一种适用于电视频段授权用户数字地面多媒体广播(DT-MB)的复合相关检测算法,可以在大载波频偏条件下保持对DTMB信号稳定的检测性能,提升了通信网络的可靠性.同时基于复合相关检测的协作频谱感知,可以有效降低隐藏终端对感知性能的不利影响,提高认知电力物联网的通信效率.     

Authentication scheme for industrial Internet of things based on DAG blockchain

Internet of things ( IoT) can provide the function of product traceability for industrial systems. Emerging blockchain technology can solve the problem that the current industrial Internet of things ( IIoT) system lacks unified product data sharing services. Blockchain technology based on the directed acyclic graph (DAG) structure is more suitable for high concurrency environments. But due to its distributed architecture foundation, direct storage of product data will cause authentication problems in data management. In response, IIoT based on DAG blockchain is proposed in this paper, which can provide efficient data management for product data stored on DAG blockchain, and an authentication scheme suitable for this structure is given. The security of the scheme is based on a discrete-logarithm-based assumption put forth by Lysyanskaya, Rivest, Sahai and Wolf(LRSW) who also show that it holds for generic groups. The sequential aggregation signature scheme is more secure and efficient, and the new scheme is safe in theory and it is more efficient in engineering.     

继电保护装置寿命分析及寿命影响机理的探讨

在本文中对继电保护装置的寿命进行分析,并且研究继电保护装置的寿命影响机理,以提升装置的使用年限.