基于区块链的支持访问控制的可搜索加密方案

区块链技术因其分布式、去中心化、不可篡改等特点在多个领域得到广泛应用.然而,这些特点同时带来了大量的数据冗余与计算冗余,不能很好地适应区块链在数据规模较大的实际业务场景下的应用.针对链上数据容量较小的问题,设计了一种基于区块链的数据链上链下混合存储架构,利用云存储实现大规模数据外包存储功能;采用对称加密技术、可搜索加密...     

基于区块链的资格认证平台的设计

文章提出一种方案,将区块链技术应用于资格认证领域,可实时验证资格证的真伪,并将资格信息实时上链存储,保证资格证数据的安全性和不可篡改性,从而解决资格证实时认证难、资格证数据易伪造以及不同资格认证机构之间数据共享难的问题。     

基于区块链技术的数字资源版权保护系统

文章主要论述基于区块链技术的数字资源版权保护系统。系统包括五个模块：登录与注册模块、数字资源上传模块、数字资源转让模块、版权保护模块和系统管理模块。系统通过“区块链”+“版权保护”,实现链上链下相结合,全链条监控。利用区块链技术,将数字资源版权保护的关键数据上链,做到信息公开透明;将链上链下相结合,确保信息真实可控;智能合约让数字资源版权保护流程良性循环,共识机制确保数据的一致性且不可篡改。     

基于区块链的智慧司法应用研究

区块链技术由于其链条组成的特殊性,有着数据难以篡改、去中心化两大核心优势,依托以上特性,使得区块链上链的相关数据信息更加真实可靠,能够有效助力司法效率和司法公信提升。通过分析智慧司法在可信认证中面临的前景和挑战,提出引入区块链共识机制、分布式账本等关键技术,助力司法手段变革。文章从区块链智慧司法的总体架构出发,为区块链技术的可靠性提供理论依据,进而引申出区块链技术在智慧司法诉讼服务全流程保障、电子卷宗存证验证、减刑假释存证验证等需要严谨性的场景应用,最终为基于区块链技术的智慧司法开展业务创新应用提供理论支持。     

基于区块链高速共识方法的物联网源端数据存储技术研究

针对物联网源端数据在传输过程中易被篡改、可信度低等痛点，结合区块链技术分布式存储、数据可溯源、不可篡改等特性，在传统的物联网数据传输方式的基础上，研究了基于区块链高速共识方法的物联网源端数据存储方式。将区块链共识节点部署在采集侧的区块链物联网关，并使用区块链对采集传感器设备进行身份认证，保证数据只能由经过区块链认证的设备上链，确保数据从源头可信。同时将区块链共识节点部署于服务器机房和物联网采集侧，保证了当采集侧区块链共识节点由于故障断开连接时，区块链网络仍能稳定运行。同时，研究并优化了区块链主节点选举方法和共识方法，以达到提高联盟链稳定性和数据传输安全性的目的，实现物联网采集数据从源头到存储全程可信、可控、可溯源。     

基于区块链的Handle标识系统

面对日益剧增的数据量，传统的中心化服务器、数据库的负荷急剧增加乃至难以为继。基于区块链系统的不可篡改和永久存储特性，提出一种基于区块链的Handle标识系统。该系统通过IPFS网络和区块链技术建立了一个去中心化的、不可篡改的、分布式云存储和查询平台，能够将标识对象的信息与Handle标识绑定一同写入到区块链和IPFS网络中，结合AES加密算法保证数据的安全和稳定性。实验表明，该系统能够在保证Handle后缀唯一性的同时，完成标识和存储数据的绑定，实现了数据对象标识的生成和解析。     

基于区块链技术的跨域认证方案

针对现有交互频繁的信息服务信任域（PKI域和IBC域）之间不能实现信息服务实体（ISE）安全高效的跨域认证的问题,提出一种基于区块链的跨异构域认证方案.在IBC域设置区块链域代理服务器参与SM9（国产标识密码）算法中密钥生成,并与PKI域区块链证书服务器等构成联盟链模型,利用区块链技术去中心化信任、数据不易篡改等优点保证模型内第三方服务器的可信性.基于此设计了跨域认证协议与重认证协议,并进行SOV逻辑证明.分析表明,与目前相关方案相比,协议在满足安全需求的前提下,降低了用户终端的计算量、通信量和存储负担,简化了重认证过程,实现域间安全通信,在信息服务跨异构域身份认证过程中具有良好的实用性.     

一种基于群签名密钥协商算法的多方参与完整性验证方案

针对政务数据合规审查中对数据完整性审查的精确性和可靠性需求,利用区块链的可溯源、不可篡改等特性,提出一种基于区块链的群签名密钥协商算法,提升数据完整性验证过程的效率和准确率。首先将需要保证完整性的数据加密保存在区块链channel上,并定期对数据更新进行上链操作;然后在需要验证完整性时加入区块链并对数据明文进行摘要比对,完成完整性检查,同时引入群签名解决上链前加密数据的线性增长效率问题。经过测试对比,算法具有较高的效率和安全性,具有一定的工程化价值。     

基于BSN的实习管理系统的设计与实现

阐述Spring Boot+VUE前后端分离架构，结合BSN的Fabric区块链平台和智能合约技术，将区块链技术应用在实习管理系统中。基于区块链技术中数据不可篡改、不可伪造和去中心化的特性，此系统解决伪造数据的问题，实现可信评价的查询。     

基于区块链的安全可信分布式大数据管理系统

本文设计一种应用区块链技术的大数据管理系统及方法,涉及区块链技术领域,本发明包括数据库层、区块链层、数据共享层和数据应用层,本发明通过采用区块链技术,实现大数据管理,构建出包括数据库层、区块链层、数据共享层和数据应用层的架构体系,充分利用区块链技术的去中心化、不可篡改、分布式共同记账、非对称加密和数据安全存储等特点,实...     

基于无源定位的多目标航迹融合技术研究

针对无源定位系统定位误差大、数据更新率不规则等问题,研究了一种通过定位数据辅助信息特征进行多目标航迹融合的新方法。该方法利用信号侦察获取的目标辅助信息作为航迹关联判决准则,并与传统的航迹关联方法相结合,从而实现了对侦察区域内多目标的航迹融合。对该算法的性能分析和仿真验证表明,新算法具有更好的航迹融合性能,更强的通用性和可扩展性;并且在密集多目标环境下可实时、有效地跟踪几十批次的目标。     

利用多普勒的运动单站直接定位算法

针对利用运动单站接收辐射源信号进行目标定位过程中,传统两步定位算法测量参数时会产生信息损失,从而导致估计精度不够理想的问题,提出了一种联合多普勒的运动单站直接定位算法。该算法通过构造代价函数,得到包含辐射源位置信息的共轭矩阵,然后分别针对未知信号和已知信号通过特征值分解求取共轭矩阵的最大特征值,最后进行二维格网型空间索引得到辐射源的位置估计。同时,本文还推导了相应的克拉美罗下界(CRLB),并分析了多普勒测量存在误差下算法的定位性能以及算法的运算量。通过理论分析和仿真实验可以表明,所提出的运动单站直接定位算法对目标位置估计误差能够逼近CRLB,且与两步定位算法相比,具有更好的定位精度。      

Performance analysis of geography‐limited broadcasting in multihop wireless networks

In multihop wireless networks, delivering a packet to all nodes within a specified geographic distance from the source is a packet forwarding primitive (geography‐limited broadcasting), which has a wide range of applications including disaster recovery, environment monitoring, intelligent transportation, battlefield communications, and location‐based services. Geography‐limited broadcasting, however, relies on all nodes having continuous access to precise location information, which may not be always achievable. In this paper, we consider achieving geography‐limited broadcasting by means of the time‐to‐live (TTL) forwarding, which limits the propagation of a packet within a specified number of hops from the source. Because TTL operation does not require location information, it can be used universally under all conditions. Our analytical results, which are validated by simulations, confirm that TTL‐based forwarding can match the performance of the traditional location‐based geography‐limited broadcasting in terms of the area coverage as well as the broadcasting overhead. It is shown that the TTL‐based approach provides a practical trade‐off between geographic coverage and broadcast overhead. By not delivering the packet to a tiny fraction of the total node population, all of which are located near the boundary of the target area, TTL‐based approach reduces the broadcast overhead significantly. This coverage‐overhead trade‐off is useful if the significance of packet delivery reduces proportionally to the distance from the source. Copyright © 2011 John Wiley & Sons, Ltd.     

一种深度学习辅助的探地雷达定位方法

在恶劣条件下,例如在雨、雪、沙尘、强光以及黑夜等环境下,自动驾驶方案中常用的视觉和激光传感器因为无法准确感知外界环境而面临失效问题。因此,该文提出一种通过深度学习辅助的探地雷达感知地下目标特征用于车辆定位的方法。所提方法分为离线建图和在线定位两个阶段。在离线建图阶段,首先利用探地雷达采集地下目标的回波数据,然后使用深度卷积神经网络(DCNN)提取采集的地下回波数据中的目标特征,同时存储提取的目标特征和当前地理位置信息,形成地下目标特征指纹地图。在定位阶段,首先利用DCNN提取探地雷达采集到的当前地下回波数据中的目标特征。然后基于粒子群优化方法搜索特征指纹地图中与当前提取的目标特征最相似的特征,并输出该特征的地理位置信息,作为探地雷达定位车辆的结果。最后利用卡尔曼滤波融合探地雷达定位结果和测距轮测量的里程信息,得到高精度的定位结果。实验选取地下目标丰富的场景和实际城市道路场景来测试所提方法的定位性能。实验结果表明,与单一使用探地雷达原始回波数据地图的定位方法相比,深度学习辅助的探地雷达定位方法能避免直接计算原始雷达回波数据间的相似度,减少数据计算量以及数据传输量,具有实时定位能力,同时特征指纹地图对回波数据的变化有鲁棒性,因此所提方法的平均定位误差减少约70%。深度学习辅助的探地雷达定位方法可作为未来自动驾驶车辆在恶劣环境下感知定位方法的补充。     

Design of Dead-End-Avoidance Method for Geographic Forwarding in MANET

Geographic forwarding is part of geographic routing in that each node only needs to know the location of its neighbors and the destination. This method can reduce the cost of table-driven routing which needs to maintain the whole path, even if the path is not in use. It also saves time when searching the path, as compared with reactive routing. When using geographic forwarding, it usually happens that the local maximum cannot forward the packet directly to the destination; this fundamental problem is called Dead End. We use the A star (A*) algorithm, which is usually used in role-playing or strategic games, to detour around terrain that cannot be passed through directly. Nodes must vote on an agent in a specific area to be a decision-maker and find a reference route for the source node. When the route is decided, geographic forwarding is used according to this reference path to the destination to avoid the dead end.     

Location safety protection in ad hoc networks

Many routing protocols and applications developed for ad hoc networks rely on location information of participating nodes. The exposure of such information, however, presents significant safety threats to the networks. In this paper, we investigate the problem of preventing an adversary from locating (and thus destroying) nodes based on their location information they disclose in communications. Our idea is to reduce location resolution to achieve a desired level of safety protection. We define the safety level of a geographic region to be the ratio of its area and the number of nodes inside it. The higher safety level a region has, the less attractive for an adversary to search over it for the nodes. When a node has to disclose its location, it can compute a cloaking box that meets a desired level of safety requirement and report that as its current location information. To implement this simple idea, there are several challenges. First, each cloaking box must be as small as possible in order to minimize the impact of reduced location resolution on the efficiency of network operating and applications. Second, nodes must be able to compute their cloaking boxes without having to reveal their accurate position. Finally, given a sequence of cloaking boxes, they must not be correlated to refine an area whose safety level is less than the requirement. Our research addresses these challenges with cost-effective solutions in the context of both stationary and mobile ad hoc networks. We evaluate the performance of our techniques through both mathematical analysis and simulation. In addition, we present a new geographic routing protocol which can work with blurred location information and evaluate the impact of location resolution reduction on the performance of this technique.     

Energy Efficient Location Error Resilient Connectivity in Wireless Sensor Networks

Geographic routing for realistic conditions is often permeated with localization errors resulting in poor performance and high energy consumption. We propose a simple yet novel geographic routing method to accomplish routing in the presence of location and channel errors. In this algorithm, it is proposed that next hop node is selected based on the combined probability of distance, estimated location error and estimated channel access probability associated with neighbor nodes. The metrics observed for performance were the successful packet delivery rate and the energy consumed. Our algorithms performance is better compared to greedy forwarding techniques of algorithms such as Greedy routing scheme (GRS) and geographic random forwarding (GeRaF). Simulations show the throughput for our algorithm is better compared to others along with reducing the energy wasted on lost packets.

     

轨道交通车辆用电缆RAMS分析

介绍了国际铁路行业IRIS(国际铁路工业标准)认证的基本情况、认证标准的发展过程,以及其中RAMS(可靠性、可用性、可维修性、安全性)部分内容的关键作用。对RAMS内容与电缆行业的匹配性、适用性及具体执行过程进行解读与说明。基于轨道交通车辆用电缆为单一部件的特点以及失效后只能更换的特性,故只适用于可靠性和安全性的要求。同时,确认电缆产品通过试验保证可靠性、通过Arrhenius方法推导90℃热寿命超过30年保证安全性。希望以此为计划进行IRIS认证的电缆企业提供参考。     

Hash-Based Virtual Hierarchies for Scalable Location Service in Mobile Ad-hoc Networks

A location service is an essential prerequisite for geographic routing protocols for MANETs. We present VHLS, a new distributed location service protocol, that features a dynamic location server selection mechanism and adapts to network traffic workload, minimizing the overall location service overhead. We demonstrate that the ratio of location queries to updates is an important performance parameter in such protocols. Our analysis and simulations show that VHLS provides better query success rates, location service quality, and geographic routing performance than the GLS and GHLS protocols. VHLS also scales well as the network size and traffic workload increases.     

基于Delaunay图形识别的移动网络位置区规划方法研究

传统的移动通信网络位置区核查需要人工操作,费时费力、效率低下,出错概率高。本文对一种基于Delaunay图形识别方法的移动网位置区准确性核查的方法进行了深入研究,通过图论理论可以准确找出基站邻区关系、准确判断插花站点,同时还可以进行多网络位置区的协同优化,极大提高了网络优化工作的工作效率,可以高效处理大量依赖地理信息的网络工作,为网络优化工作提供了技术保障。