ECBAR系统中群体研讨信息可视化的算法研究*

电子公共大脑视听室为群体研讨提供了动态的可视化信息显示模式,深入研究了其群体研讨信息的自然可视化、自主可视化和智能可视化实现的算法和功能,有助于促进达成共识并有效辅助决策。     

群体研讨信息智能可视化研究*

重点介绍了智能可视化的各种形式和内容,包括研讨信息统计可视化、关注水平及其状态可视化、共识水平及其状态可视化、共识分析可视化、共识变化预测与建议可视化等,并最终在ECBAR系统中实现了其功能。     

一种研讨信息组织模型及其在研讨厅中的应用*

在群体研讨过程中会产生大量的研讨信息,群体共识则蕴藏在这些研讨信息之中,因此有必要对研讨信息进行分析处理。为此,提出一种面向群体共识涌现的研讨信息组织模型(DISM)。该模型根据Toulmin逻辑对专家发言进行结构化处理,将专家发言分解为根据、论证、模态限定和主张等几个部分。其中,模态限定是一个可量化的部件,反映了专家对主张的态度;根据和论证则为主张提供支持。该模型是对研讨信息的全面描述,可以有效处理研讨信息并支持共识达成,最后阐述了该模型在综合集成研讨厅中的应用。     

用户驱动的研讨信息可视化平台的设计与实现

在“以计算机为媒介的群体沟通”环境下,常常出现“知识断层”和“信息过载”。研讨信息可视化丰富了研究和认知手段以及群体发现信息的途径,因而成为缓解“信息过载”的一个重要途径。以研讨用户为中心,从单个信息、信息关系、了解研讨状态、把握研讨过程四个方面识别出研讨用户的信息寻找、发现以及获取的需求;并基于群体研讨支持系统的信息组织模型,设计了用户驱动的研讨信息可视化平台,并结合J2EE、XML、计算机图形学等技术,实现了可视化平台,并结合一个具体应用示范了平台的功能。     

支持共识决策过程的群排序集结

为了支持共识决策过程,引入最大共识排序概念,设计了基于共识排序树的群排序集结算法。该算法能够从排序数据中发现最大共识排序和需要进一步协商的冲突项目。应用模拟数据进行实验,结果表明了这种计算方法的有效性。     

基于Web的群体研讨系统

基于Web的群体研讨系统,不仅支持成员跨平台研讨,而且能够对研讨过程中产生的发言信息进行有效管理,并支持共识达成。本文以综合集成方法论为指导,给出基于Web的群体研讨平台的理论基础、系统建模、系统框架及系统实现方法。以“我国新农合发展所存在的问题”为主题,在建成的平台上进行模拟研讨,并对结果进行分析。一方面验证了系统的可行性,另一方面为新农合相关主题的进一步深入研究奠定理论基础。     

一种基于信噪比加权共识的合作频谱感知算法

以基于平均共识的分布式合作频谱感知算法为基础,提出了一种基于信噪比加权共识的合作频谱感知算法.该算法在平均共识收敛过程中引入能够反映用户的平均信噪比的权重,并以平均共识收敛值为参考确定相应的权重.在不需要信噪比信息的条件下,算法实现了认知Ad Hoc网络中基于信噪比的频谱感知信息加权共识.分析和仿真表明,在用户具有不同的平均信噪比的情况下,该算法克服了基于平均共识的分布式合作频谱感知算法无法体现用户信噪比差异的缺陷,提高了频谱感知的性能.     

研讨信息交互式可视化平台设计与实现

针对传统研讨信息静态可视化视图杂乱、难以辨认等问题,提出研讨信息可视化框架和基于交互式可视化技术的解决方案。利用Java、XML技术,借助JFreeChar、Prefuse软件包实现交互式可视化平台。该平台基于节点链接结构,允许用户交互式操作,支持可视化检索和分析。运行结果表明,该平台改善了研讨信息的可访问性,具有较强的可扩展性。     

面向物联网系统的改进PBFT共识机制

针对复杂网络环境中,基于传统PBFT共识算法的物联网系统存在恶意伪装设备和共识响应延迟高的问题,提出一种基于位置和时间的可信双层PBFT共识机制(credible-location-and-time-based Byzantine fault tolerant algorithm, CBFT)。根据边缘服务器的位置信息对设备进行分组,使用GeoHash(geographical hash, GeoHash)协议创建设备的位置定时器,根据定时器的可信时间遴选出诚信设备;基于边缘服务器的信用值生成两层网络,并行开展共识,分解共识任务;引入基于Token的信用评价机制,激励边缘服务器规范共识行为。实验结果表明,改进的共识机制能够有效筛选出恶意设备,降低共识耗时并提高系统吞吐量。     

基于自定义日志的Fabric的共识交易轨迹可视化追踪方法

联盟链缺少展示各个节点资源使用情况、健康状态、互相关系、共识交易流程等方面的可视化方法,为此提出一种基于自定义日志的Fabric共识交易轨迹追踪方法（FTL）。首先,以典型联盟链框架Hyperledger Fabric为基础设施实现区块链底层构建;然后,利用ELK工具链收集与解析Fabric的自定义共识交易日志,并利用Spring Boot作为业务逻辑处理框架;最后,采用专注于图分析领域的Graphin实现共识交易轨迹的可视化。实验结果表明,与原生Fabric应用相比,基于FTL的Fabric的应用框架在实现可视化追踪基础后,平均性能仅下降了8.8%,未造成显著延迟,可以为监管方提供更加智能的区块链监管方案。     

区块链共识算法演进过程

基于比特币技术衍生出了大量虚拟货币,其主要特点是对于比特币共识算法的优化和共识算法模式的变革。为研究共识算法演化历程,以比特币共识机制作为切入点,从源代码层级解析了比特币共识算法工作量证明（proof of work,POW）的工作原理及其优缺点,同时分析了比特币演进产生的以太坊共识算法。在理论探讨后,利用洛伦兹曲线及基尼系数评价比特币、以太坊共识机制的实际去中心化效果;并介绍了权益证明（proof of stake,POS）、股份授权证明机制（delegated proof of stake,DPOS）、实用拜占庭容错算法（practical Byzantine fault tolerance,PBFT）的演进过程及算法原理。最后,从共识算法去中心化能力、激励机制、处理效率、分布式安全性等方面进行了比较,得到了共识算法得分表及得分雷达图,以期为未来不同场景、不同需求的区块链应用提供共识算法分析标准。     

Group consensus of multi-agent systems with directed information exchange

We discuss a new consensus problem – a group consensus problem – in networks of dynamic agents. For a complex network consisting of several sub-networks owing to physical quantities or task distributions, it is concerned with this case that the agents in a sub-network share a consistent value while there is no agreement between any two sub-networks. When the information exchange is directed, a novel consensus protocol is designed to solve the group consensus problem. The convergence analysis is discussed and several criteria are established based on graph theories and matrix theories. Simulation results are presented to demonstrate the effectiveness of the theoretical results.     

Admissible Consensus of Multi‐Agent Singular Systems

Consensus problems are studied for both continuous‐time and discrete‐time multi‐agent singular systems with time‐invariant and directed communication topologies. Under restricted system equivalence of singular agents, sufficient and necessary conditions are obtained for admissible consensus ability with static protocols, which are based on both the relative information of the dynamic states and the absolute information of the static states. For a network of continuous‐time singular systems, the existence of admissible consensualization can be cast into strong stabilizability of the agent dynamics. Once discrete‐time multi‐agent singular systems satisfy the condition of reaching nontrivial final consensus states, strong stabilizability is a sufficient condition to achieve admissible consensualization. Two algorithms are proposed to construct two protocols, which are based on a linear matrix inequality and a modified Riccati equation, respectively. Finally, the algorithms are illustrated by two simulation examples.     

Event‐Based Semiglobal Consensus of Homogenous Linear Multi‐Agent Systems Subject to Input Saturation

In this paper, we consider the semiglobal leader‐following consensus of general linear multi‐agent systems subject to input saturation. First, an event‐triggered control protocol is provided to ensure semiglobal consensus of the multi‐agent systems, in which the agents should continuously monitor the information of their neighbors. Second, a self‐triggered control protocol is proposed to guarantee the semiglobal consensus of the multi‐agent systems, in which the agents only have access to the information of their neighbors in discrete time instants. Moreover, both event‐triggered control protocol and self‐triggered control protocol are proved to be Zeno‐free, that is, the inter‐event times for such two protocols have positive lower bounds. Finally, two numerical examples are provided to illustrate the effectiveness of the proposed event‐based semiglobal consensus protocols.     

Consensus control of discrete-time multi-agent systems with privacy preservation

Due to the dependence of consensus theory on multi-agent systems (MAS) and the need to openly exchange status information with neighbors on each agent, private status and information are inevitably exposed to the public. In this paper, we present a consensus privacy protection algorithm to solve the consensus privacy problem of second-order MAS. The proposed approach is based on the Paillier algorithm with semi-homomorphic characteristics while combining a distributed control perspective to solve the privacy issues of sharing system status information. Under the conditions of our design, as long as there is at least one trustworthy neighbor node, the privacy of the topology nodes can be protected, and thus, the interconnected nodes are unable to detect the state information of systems from one another. We provide a new method for the privacy of the state information of the discrete-time MAS and use restricted hardware devices to implement the consensus control. Finally, experiments verify the effectiveness of our method, while meeting the actual applicability     

基于事件触发二阶多智能体系统的固定时间比例一致性

研究了在无向拓扑下,由多个子群组成的二阶多智能体系统的固定时间比例一致性问题,采用反推法设计了一种基于事件触发的固定时间非线性比例一致控制策略,该策略包含分段式事件触发函数:当智能体在追踪虚拟速度时,给出了基于速度信息的触发条件;当智能体速度与虚拟速度达到一致时,切换至基于位置信息的触发条件,可有效减少系统能量耗散及控...     

Consensus of linear multi-agent systems with communication delays by using the information of second-order neighbours under intermittent communication topology

This paper investigates the consensus of identical linear multi-agent systems with aperiodic intermittent communication topology by using the information of second-order neighbours (two-hop neighbourhood). The protocols based on two-hop neighbourhood information and intermittent communication topology are designed, under which consensus is reached. If the communication rate is larger than the corresponding threshold value, the networks will accelerate consensus by using two-hop neighbourhood information. By means of switching systems theory and Lyapunov–Razumikhin theorem, consensus of multi-agent systems with communication delays and intermittent communication topology is reached by two-hop neighbourhood information. Finally, simulation examples are provided to show the effectiveness of the theoretical results.     

基于双层架构的溯源许可链共识机制

区块链中的区块按照时间历史顺序进行排列,同时通过数据加密技术以及共识机制使区块链具有不可篡改性,这使产品溯源成为区块链的重要应用场景。选择产品信息追溯技术要考虑技术的可行性同时要考虑产品以及生产者的市场属性,这使许可链代替公有链成为产品信息溯源的重要部署方式。现有研究成果中对溯源许可链的研究多停留在机制设计和框架建构上,少有对适用于产品信息溯源的共识算法进行研究。在技术工程实践过程中,联盟链中多选用实用拜占庭容错（PBFT,practical byzantine fault tolerance）作为溯源链的共识机制（如超级账本项目 Hyperledger）,但随着参与节点数量的增加,溯源链的运行效率明显下降,延迟时间明显提高,致使多数项目依然处于实验阶段。基于此,提出基于双层架构的溯源许可链共识机制（DLPCM）。首先将参与者在垂直维度上化分为两层,其次在不同层次上根据区块链的不同部署方式采用不同的共识机制,最后对该共识机制下的溯源信息查询机制进行介绍,为基于许可链的溯源系统的开发和设计提供了重要借鉴。     

基于不确定性度量信息融合的团队一致法研究

给出一种新的信息融合方法--基于不确定性度量的团队一致法.这个方法是基于 一个迭代的团队不确定性度量函数,它能使团队成员达到一致;该方法用于融合从多个图象传 感器得到的对同一个目标的关于目标类别不确定性信息,与其它方法相比该方法有效而简单. 在多图象目标识别中有着广泛的应用.还给出了确定权值系数的一般方法.把这种方法用于一 个现成的实例,得到的结果和多数结合算子的结果一致.