结合谓词感知与图注意力机制的链接预测方法

知识图谱补全旨在预测三元组中缺失的部分使知识图谱趋于完整.针对基于神经网络等模型的链接预测方法忽略了实体间的关联信息,导致模型不能覆盖三元组周围局部邻域中固有的隐藏信息,提出图注意力机制与谓词感知结合的方法.首先,利用图注意力机制定义了一个关系嵌入矩阵,描述任意给定实体邻域内实体间的关系;其次,引入谓词增强实体间语义理解程度,构造了基于谓词嵌入向量的注意力值计算公式,以便有效地度量实体间语义联系的强度;此外,利用实体邻居间的边关系预测多跳实体间的直接关系以补全知识图谱.在数据集WN18RR、Kinship、FB15K的实验结果表明了该方法能有效提高三元组的预测精度.     

机电设备红外故障诊断的可诊性研究

讨论了机电设备红外故障诊断的可诊性及其影响因素,给出了红外故障诊断可诊性的评价指标体系,研究了影响因素之间的相关性问题,并将其归类为不同可诊性的模式识别或分类问题。通过协方差和均值计算方法讨论了样本数目的影响。这对于红外技术在机电设备故障诊断上的应用具有一定的参考价值。     

频谱切换中基于频谱感知的链路保持概率

为分析频谱感知对认知用户通信性能的影响,定量研究频谱切换中认知用户的相关参数,推导了频谱切换中基于频谱感知的链路保持概率及平均传输时间。得到认知用户在一次通信中能完成数据传输的概率和通信中的有效数据传输速率。仿真分析表明:在不同频谱环境下,基于频谱感知的频谱切换性能要比非频谱切换和基于频谱感知的信道预测方案的性能稳定,尤其是当授权用户到达率较高时更明显。此外,仿真数据表明:频谱感知中的错误信道选择概率和感知时间是影响频谱切换性能的两大重要因素。     

SILEX检测与验证

评述了首次实现星问光学连接的欧洲空间局(ESA)的SILEX计划的检测与验证方法,相信对我国星间光通信技术的研究与发展具有一定的促进作用。     

基于车路协同的地下停车场车辆定位算法发散性研究

针对GPS信号弱或不可用场景下(如隧道、地下停车场等)智能车辆的高精度定位服务问题,分析了一类基于车载网络通信(VANET)的无线定位算法,通过车辆—智能路基之间的信息交互,以解决现有车辆定位过程中有效精度低、抗干扰能力差等问题。但考虑到车辆移动造成的网络拓扑结构动态变化,车辆与智能路基之间的非对称通信时延往往被忽略,导致协同定位模型过于简化,造成车辆定位精度的损失。通过刻画车辆—智能路基之间的非对称通信模型,从数学角度分析验证了现有车辆协同定位算法的发散性。仿真结果表明,在不考虑非对称通信延迟的条件下,对车辆的定位误差会逐级收敛;但在考虑非对称延迟的条件下,则呈现指数级振荡发散。     

基于聚类信息和对称非负矩阵分解的链路预测模型研究

现有的大部分基于非负矩阵分解的链路预测方法仅考虑网络拓扑结构信息而忽略节点与链接聚类信息.针对此问题,提出一个融合聚类信息的对称非负矩阵分解的链路预测模型.首先,该模型利用对称非负矩阵分解去捕获网络节点相似度信息;其次,使用基于Jaccard的节点和链接聚类系数去保持网络局部结构信息;最后,启用拉格朗日乘法规则去学习模型参数.在六个真实无向无权和四个加权网络上的实验结果表明,该方法在两种不同类型网络预测精确度分别提升了1.6％和8.9％.     

基于TD-HSUPA新增信道链路预算

本文简要概述了TD-HSUPA新增物理信道以及链路预算的一般应用模型,详述了链路预算基本参数取值和传播模型的选取,并对TD-HSUPA新增物理信道进行初步链路预算并估算出其小区覆盖半径,来解决容量和覆盖规划的平衡问题。     

A methodology for the characterization of environmental effects on global navigation satellite system (GNSS) propagation

In this paper a methodology for the characterization of environment-related (shadowing and multipath) propagation effects on multi-satellite systems is presented. This work is focused on availability and performance evaluation of global navigation satellite systems (GNSSs). The definition of next-generation GNSSs specially designed for civil applications requires the precise understanding of propagation effects; these include not only ionospheric and tropospheric but also environmental effects, since a large group of their expected users will no longer be located in open areas with clear visibility of several satellites but in densely built-up areas subject to high blockage probabilities. Issues such as constellation definition, signal design, codeword structure, etc. require the aid of powerful analysis tools. The basic ideas for the specification of such multi-satellite propagation analysis tools are presented. This paper describes part of the work being carried out under European Space Agency (ESA) contract ESA/ESTEC 12223/96/NL/JSC. © 1998 John Wiley & Sons, Ltd.     

Semantic acid properties in multidatabases using remote procedure calls and update propagations

Global ACID properties (Atomicity, Consistency, Isolation and Durability) may be implemented by using a DDBMS (Distributed Data Base Management System.) However, in this solution data availability is low. Further, data may be blocked, i.e. if some data are locked from a remote location, the data cannot always be unlocked when the connection to the data fails. This is not a problem when client/server technology is used because client/server technology only uses local locks, a reason why multidatabases and client/server technology are widely used in real-life distributed systems. However, the trouble with such systems is that they have no inherent global ACID properties. The objective of this paper is to illustrate how global semantic ACID properties, enforced by the transactions themselves, may be implemented on top of client/server technology. This is done to preserve high data availability. The global atomicity property is implemented by using retriable and compensatable subtransactions. The global consistency property must be implemented by the transactions themselves. The global isolation property is implemented by using countermeasures to isolation anomalies. The global durability property is implemented by using the durability property of the local DBMSs. The largest bank in Denmark, Den Danske Bank, has implemented all its applications using methods described in this paper. © 1998 John Wiley & Sons, Ltd.     

电站辅机可靠性考核验证方案

为核验电站辅机的可靠性,本文介绍了以平均无故障运行时间和可用系数为指标,利用电站现场支行数据对电站辅机进行可靠性指标验证的方案和相应的实例,可供电站辅机制造行业和电力运行部门制定可靠性考核方法时参考。