采用模型检测器的软件安全模型验证方法

针对软件开发过程中安全性分析与设计不足的问题,在研究现有软件安全性建模及形式化验证技术的基础上,提出了一种适用于面向对象的软件安全性建模与验证方法.建立软件安全属性的非形式化UML模型,采用安全扩展有限自动机创建其形式化模型,并使用线性时序逻辑描述安全属性,将形式化模型与安全属性共同作为模型检测器的输入,得到模型是否满足性质的验证结果,从而实现了软件安全设计与验证技术的有机结合.实验结果表明,该方法能够在软件设计初期对所涉及的安全性进行有效分析与验证.     

物联网时空语义模型构建

信息感知和处理是物联网最基本的功能,时空特性对其具有特殊意义.时空语义是地理信息系统领域用于描述地理实体的一种方法.将时空语义概念引入到物联网,深入挖掘物联网的时空关联特性,并将时空变化作为时空对象的一个内在特性,构建了物联网时空语义模型.模型通过对象级变化图和属性级变化图对时空对象和时空变化进行概念建模.同时,也通过这两个层次来表示时空对象的时空演变过程.最后,通过实例来说明物联网时空语义模型的建模过程,以验证模型的有效性.     

液压系统自动建模与仿真软件的研制

基于液压大系统“灰箱”建模原理与方法 ,研究开发了适用于液压大系统的自动建模与仿真软件。本文重点介绍了“灰箱”建模法的特点并应用研究软件对 15KJ电液锤液压系统进行了仿真计算     

邻居发现辅助与物联网整合应用

随着网络技术的发展,接入网络的设备已不再局限于由人操控的计算机,在物联网技术极大的丰富物理信息世界的同时,拓扑的动态性也带来了与传统网络不同的移动性问题。如何对节点进行高效的定位和数据传输成为需要解决的问题。笔者结合IPv6本身对移动性的支持和邻居发现机制,提出了一种使用邻居发现机制的移动节点辅助连接方法,并拟定了在6LowPAN中的实现方案,使6LowPAN与传感器、射频识别和控制终端等结合,实现局域物联网内以IPv6方式连接,满足小范围移动切换需求,通过IPv6接入Dragon-Lab联邦网络,实现全IPv6的物联网应用模型。     

基于反应基元的非线性系统灰箱建模方法

提出一种基于反应基元的建立复杂非线性系统模型的灰箱建模方法.首先根据先验知识及系统特性分析引入过程的初始反应基元,并以此为出发点建立结构逼近神经网络模型,实现基元之间的关联,赋予网络节点实际的物理意义;然后,通过提出的最小化预测误差,结合逐步回归分析方法选择最优反应基元,优化网络结构,建立起表示系统变量关系的灰箱模型.以实际橡胶硫化促进剂制备的间歇反应过程作为实验对象,建立以生成物浓度为输出的数学模型,达到较高的输出预测精度.     

基于混成自动机的CPS行为建模与属性验证

系统实时性、安全性和可靠性等非功能属性是信息物理系统在诸多领域应用的关键因素。论文在分析CPS模型构建与分析验证中面临的挑战的基础上,提出了一种CPS行为建模与属性验证方法。该方法首先基于混成自动机对CPS的行为进行建模,然后将此模型转换为混合程序模型,最后在定理证明器KeYmaera中对HP模型的属性进行形式化验证。文中论述了行为模型描述语言的结构,建立了混成自动机模型与HP模型之间的转换规则,分析了模型转换的一致性。应用实例表明:该方法既能简单直观地描述CPS动态行为,又能对CPS的属性进行严格的形式化验证,且有效避免了形式化验证中的状态空间爆炸问题。     

物联网服务的π-演算建模与验证

针对物联网服务建模和验证问题,用π-演算理论对物联网服务和环境实体进行动态交互行为建模,并引入μ-演算刻画物联网服务能力,将其描述为物联网服务和环境实体动态交互行为的执行序列。针对特定的应用场景,使用π-演算定义了物联网服务和环境实体,利用μ-演算对物联网服务能力进行建模,使用检测工具MWB验证了模型的安全性、活性和时间约束三个性质,为物联网服务建模和验证提供了参考。     

基于Petri网的技术在电子政务办公系统中的应用

通过对基于Petri网的工作流建模技术的描述,介绍了与此相关的核心技术,研究分析了实际工作过程中电子政务办公系统中的发文管理的业务流程,引入了Petri网和工作流建模技术,结合具体实例提出了一种基于Petri网的电子政务办公工作流模型,并对该模型进行了可达性验证和合理性验证,二次开发后的验证结果和实践表明该模型能够有效地改善和提高电子政务办公系统的效率和实用性。     

泛在网条件下群组力移动模型的稳定性

群组移动模型是对群组终端在泛在网条件下进行移动性管理的基础。针对泛在网异构性特点,基于Lennard-Jones势能模型,提出了泛在网条件下群组力移动模型,通过引入分子间作用力的概念,对群组内各个终端的运动状态进行描述,较好地刻画了群组的移动特性;同时,通过对该模型进行Lyapunov稳定性分析,得出群组在运动过程中,各个终端运动状态趋于一致,系统趋于稳定。理论证明该模型可为群组终端在泛在网络中移动时,提供一种有效实施移动性管理的方法。     

面向移动协同的扩展式动态环境演算范型研究

针对已有移动协同研究中尚缺乏既能描述移动性、又能描述协作性的演算系统,提出了一种扩展式动态环境演算范型(EMA).在对动态环境演算中的基本概念"环境"进行深入解析的基础上给出其在协同计算情境下的新语义,之后抽取刻画协同行为的基础动作A,并将A作为刻画协作性的基本单位.进而将动作行为理论引入到动态环境演算中,即在动态环境演算的基础上将A作为参与环境演算的基本实体,从而借助已有动态环境演算对移动性的描述能力来刻画移动协同计算的移动性,同时借助A刻画了移动协同中的协作性.最后给出了基于EMA的移动协同行为实例描述.较之经典动态环境演算,EMA弥补了不能刻画移动协同中的协作性缺陷,为移动协同理论框架的完善提供了依据,为移动协同应用的构建提供了一种新的理论基础.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

英文诗歌中的喻类修辞

为了有助于提高英文爱好者的个人情操、文化素养和学习兴趣,以及专业人员对英语学习和研究进行多途径的探索,本文通过一些精选诗歌的引证和分析,着重论述了喻类修辞法在英文诗歌中的运用其及效果。     

Man Is Unable to Change the Miserable Life——Analysis of the Arrangement of Four Characters in The Glass Menagerie

Tennessee Williams is considered as one of the most important American playwrights since World War II.The Glass Menagerie is his first successful drama,which describes a tragic situation of family and means to say that Man is unable to change the miserable life,no matter whatever means he try,This essay focuses on the analysis of the arrangement of the four main characters:Laura.Amanda,Jim and Tom to reveal the theme.Laura is fragile.Amanda is brave.Jim is vital.Tom is sensible.And all of them develop and try the different means to struggle against life,but fail tragically.With the evidence,the paper comes to conclusion naturally that Man is unable to change the miserable life,and he dooms to fail.     

Characterization of root-nodulating bacteria on Retama raetam in arid Tunisian soils

The aim of this study is to investigate the diversity of Retama raetam root-nodule bacteria isolated from arid regions of Tunisia. Twelve isolates, chosen as representative for different 16S rRNA gene patterns, were characterized by 16S rRNA gene sequencing and phenotypic analysis. Isolates were assigned to Sinorhizobium, Rhizobium and Agrobacterium. Symbiotic properties of Sinorhizobium and Rhizobium isolates showed a large diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Strain RK 22 identified as Rhizobium was the most effective isolate.     

An Affordable Accurate Evaluation of the Binding Conformations Predicted by Molecular Docking Studies in Bio-System

正Recently,docking has been widely used to predict the binding-modes of protein-inhibitors,when the crystal complexes structure was absent.Most docking algorithms are able to generate a large number of probable conformations,it,however,is difficult to effectively evaluate these docking poses and identify the most reasonable bindingmode.In the present study,on the basis of the crystallographic data of human 3-hydroxy-3-methylglutaryl coenzyme     

WIMAX与WI-FI技术分析及联合组网

介绍了WiMAX与Wi-Fi两种无线宽带接入技术,并对两者之间的关系及相互之间的影响做了对比及分析,并对WiMAX的关键技术进行了详细说明,最后对两者的联合组网方式做了简单的探讨。