基于卡口上下文和深度置信网络的车辆轨迹预测模型研究

针对车辆轨迹预测中节点序列的时序特性和实际路网中的空间关联性,该文提出一种基于深度置信网络和SoftMax (DBN-SoftMax)轨迹预测方法。首先,考虑到轨迹在节点集合中的强稀疏性和一般特征学习方法对新特征的泛化能力不足,该文利用深度置信网络(DBN)较强的无监督特征学习能力,达到提取轨迹局部空间特性的目的;然后,针对轨迹的时序特性,该文采用逻辑回归的预测思路,用当前轨迹集在路网特征空间中的线性组合来预测轨迹;最后,结合自然语言处理领域中的词嵌入的思想,基于实际轨迹中节点存在的上下文关系,运用节点的向量集表征了节点间的交通时空关系。实验结果表明该模型不仅能够有效地提取轨迹特征,并且在拓扑结构复杂的路网中也能得到较好的预测结果。     

概念格的规则约简与属性特征

在研究了概念格形成的偏序结构的基础上，引进了由两个形式背景形成的决策形式背景，讨论了外延集类上等价关系和交一致关系，给出了决策形式背景下规则提取与属性约简方法．同时对于在规则约简中起不同作用的属性，区分了核心（存在于任何约简中）、相对必要属性（存在于某些约简中）和不必要属性（不存在于任何约简中），给出了各类属性的特征和判别方法．这些方法为概念格规则提取的启发式算法打下了基础．     

Maschke-type theorem and Morita context over weak Hopf algebras

This paper gives a Maschke-type theorem over semisimple weak Hopf algebras, extends the well-known Maschke-type theorem given by Cohen and Fishman and constructs a Morita context over weak Hopf algebras.     

Megaco/H.248协议的分析和研究

Megaco/H.248协议是由IETF和ITU-T最近共同研究提出的一项新标准,它是PSTN网络与IP网络之间无缝地实现各种业务和应用的多媒体标准的又一里程碑。此协议扩展了媒体网关控制,使其包含了一个独立于传输的连接模型,支持诸如多媒体会议等的高级服务,并支持各个国家的操作。本文对Megaco/H.248特征进行了描述。     

基于环境状态的移动计算

首先简要介绍了移动计算的发展和面临的问题 ,提出了基于环境状态的移动计算 ;然后解释了什么是环境状态以及其分类 ,并从环境状态出发 ,阐述了基于环境状态的移动计算的特点和类型 ;其中 ,给出了目前一些基于环境状态的移动计算的应用实例 ,以位置环境状态为例 ,提出了基于环境状态的移动计算的基本模块和所完成的功能 ;最后 ,从两种计算模型出发 ,说明目前应用的状况及以后基于环境状态的移动计算的发展     

基于最优解析树提取的多功能雷达状态快速估计方法

针对基于文法建模的多功能雷达(Multi-Function Radar,MFR)参数估计领域中常规算法具有的高运算复杂度问题,提出一种快速估计算法.该算法利用文法的派生过程仅与文法结构有关,而与文法概率参数无关这一事实,利用库克-杨-卡塞米(Cocke-Younger-Kasami,CYK)算法对截获雷达数据序列进行预处理,构造出可以反映该序列派生过程的解析表,进而从该解析表中提取出序列的最优解析树,然后利用改进的Viterbi-Score算法对雷达文法概率参数进行快速估计.论文仿真分析了该算法的计算复杂度、存储复杂度和估计精度,实验结果表明了该算法相对于常规算法,可以减少60%左右的计算量.     

Constructing knowledge about the trigonometric functions and their geometric meaning on the unit circle

Processes of knowledge construction are investigated. A learner is constructing knowledge about the trigonometric functions and their geometric meaning on the unit circle. The analysis is based on the dynamically nested epistemic action model for abstraction in context. Different tasks are offered to the learner. In his effort to perform the different tasks, he has the opportunity to understand the process used to create unit circle representations of trigonometric expressions. The theoretical framework of abstraction in context is used to analyse the evolution of the learner's construction of knowledge in the transition from ‘triangle’ trigonometry to ‘circle’ trigonometry.     

高生存性异构应急通信网络的设计与分析

针对应急通信的特点和要求,基于无线自组网构建的一种高生存性异构应急通信网络,为应急现场提供了一种可靠、灵活的通信支撑平台.首先,说明了异构应急通信网络的特点和生存性要求.然后,重点对高生存性异构应急通信网络的设计进行了阐述和分析,包括组网方式、设计策略和网络结构;最后,探讨了进一步提高应急通信网络可生存性的一些措施.     

A ranking model in uncertain, imprecise and multi-experts contexts: The application of evidence theory

We consider ranking problems where the actions are evaluated on a set of ordinal criteria. The evaluation of each alternative with respect to each criterion may be imperfect and is provided by one or several experts. We model each imperfect evaluation as a basic belief assignment (BBA). In order to rank the BBAs characterizing the performances of the actions according to each criterion, a new concept called RBBD and based on the comparison of these BBAs to ideal or nadir BBAs is proposed. This is performed using belief distances that measure the dissimilarity of each BBA to the ideal or nadir BBAs. A model inspired by Xu et al.’s method is also proposed and illustrated by a pedagogical example.     

Study of Morita contexts

Matrix congruence can be used to mimic linear maps between homogeneous quadratic polynomials in n variables. We introduce a generalization, called standard-form congruence, which mimics affine maps between non-homogeneous quadratic polynomials. Canonical forms under standard-form congruence for three-by-three matrices are derived. This is then used to give a classification of algebras defined by two generators and one degree two relation. We also apply standard-form congruence to classify homogenizations of these algebras.