一种自主免疫学习的分布式网络攻击对抗模型研究

针对网络系统容易遭受网络病毒攻击的问题,提出一种自主免疫学习的分布式网络攻击对抗模型.该网络攻击对抗模型采用分布式网络攻击检测算法来计算数据包信任值,再通过设置信任值的检测阈值,当数据包的信任值低于阈值时,判断该数据包遭到攻击.此方法可以确定数据包是否遭到病毒入侵,并对病毒的危险等级进行评估.基于人体的病毒防御机理提出适用于网络的自主免疫机制,通过带抗体的特殊数据包来清除带病毒数据包,并基于病毒的危险等级来生产适当的特殊数据包数量.在实验仿真中,算法在检测网络病毒的攻击以及清除网络病毒方面表现出良好的效果.     

别花冤枉钱 手机Micro-SD卡选购有误区

随着智能手机功能越来越强大,更多人开始将高质量的视频以及大型游戏数据包等存放与存储卡中,为此盲目进入手机Micro-SD卡高速大容量一定好的误区。Class等级不是越高越好了解手机Micro-SD卡的读者都知道,手机Micro-SD卡有等级之分。目前市场上出售的有三个常见等级,分别是Class4、Class6、Class10。不同的等级数     

DPQS:MANET中一种有效的队列调度机制

提出一种针对移动自组网的动态优先权队列调度机制(DynamicPriorityQueueScheduling,DPQS)。为缓冲区设置最大、最小两个阈值,将其分为三个不同的负载阶段,然后根据当前缓冲区的负载情况动态调整各种类型数据包的优先等级,从而在不影响快速建立路由的前提下,降低数据包在网络中的传输延时,提高网络的性能。仿真结果表明DPQS机制有效地降低了网络传输延时,并对网络的吞吐量也有一定的提高。     

IP网络上视频区分服务传输研究

文章在笔者建立的区分服务网络模型的基础上,根据视频编码的特点,提出了一种针对视帧传输的新的服务优先等级标识算法,即根据不同视频帧解码时的重要程度和网络的传输状况将不同视频帧的数据包标记为不同等级,赋予不同的质量保证。该策略是针对网络严重拥塞和极低码率视帧编码序列而提出的。实验表明,在网络严重拥塞(实际带宽低于要求带宽70%以下)、有大量数据包丢失时,也可在解码端利用差错掩盖(ErrorConcealment)技术很好地恢复出视频图像,且接收到的IP包的延迟及延迟抖动也很小,完全符合实时传输的要求。     

基于时隙选择概率分布的DCF区分服务机制

针对IEEE 802.11 DCF不能为实时业务提供服务质量保证的问题,提出一种简单的基于优先级的退避机制,根据不同等级数据业务的QoS需求提供区分服务。高优先级数据流采用减少数据包重传次数策略,低优先级数据流采用改进的RWBO+BEB退避机制,使得时隙选择概率分布均匀,能减少数据包碰撞概率。采用马尔科夫链模型对该机制进行数学分析与评价,结果表明,该机制不仅能够有效支持区分服务,并且能够提高系统饱和吞吐量。     

可编程网络流量公平调度研究综述

网络数据包调度是一个经典的多维决策问题,其核心在于网络设备中如何实时地做出数据包入队和出队的合理决策。在该领域中,流量公平调度是一个备受关注的重要课题。为了保障网络服务等级、缓解链路拥塞以及有效应对网络攻击,快速、公平且通用的调度算法显得至关重要。传统的数据包调度算法实现了公平的带宽分配和流量隔离,但随着软件定义网络(SDN)和可编程网络的出现和发展,灵活且可重构的网络编程方式催生了许多国内外学者提出创新性和实用性的公平调度方案。本文围绕流量公平调度问题,系统地总结了实现公平调度的6种技术路线,并展望了未来的研究方向。     

9PQS：MANET中一种有效的队列调度机制

提出一种针对移动自组网的动态优先权队列调度机制（Dynamic Priority Queue Scheduling，DPQS）。为缓冲区设置最大、最小两个阈值，将其分为三个不同的负载阶段，然后根据当前缓冲区的负载情况动态调整各种类型数据包的优先等级，从而在不影响快速建立路由的前提下，降低数据包在网络中的传输延时，提高网络的性能。仿真结果表明DPQS机制有效地降低了网络传输延时，并对网络的吞吐量也有一定的提高。     

网络数据包的协议分析算法设计与实现

为有效地监听网络状况和数据传输,截获网络传输的数据包,分析网络性能,排除网络故障,文中在以太网的基础上,通过对网络数据包的协议分析,设计并实现了一个网络数据包的协议分析算法(PLA算法)。PLA算法可以有效地对网络中传输的数据包进行协议分析,解决了如何判别在网络上传输的数据包是什么类型的数据包,每一个数据包都用到了哪些协议。通过PLA算法对数据包的分析,可以使得流量统计和流量收费更加精确。     

基于时间复杂度的无线网络编码数据包平均传输次数优化分析

为提高无线网络编码数据包传输效能,提出了基于时间复杂度的无线网络编码数据包平均传输次数优化方法。首先分析无线网络编码数据包传输信道的多径特性,并根据数据包的多径特性采集有效且安全的数据包,同时在IEEE802.3EFM通信协议下构建数据包的传输信道模型。为提升数据包的传输及存储性能,需建立缓存反馈机制,在该机制作用下设计混合编码。最后采用自适应量化融合编码的方法,进行无线网络编码数据包传输的调制解调处理,结合时间复杂度的衡量算法实现无线网络编码数据包传输的传输次数优化,提升了无线网络混合编码下数据包的传传输效能。仿真结果表明,采用该方法进行无线网络编码数据包传输的输出均衡性较好,传输误码率较低,时间开销较短。     

基于Winpcap的LAN数据包处理系统

在大量网络应用中都需要分析和应用网络各层协议,为此需要从网络截获数据包。应用Winpcap在以太网上俘获数据包,从物理层到MAC层构造出标准的网络数据包,实现对一个网络数据包拆分的逆过程,此过程是根据用户设置的过滤规则捕获网络封包,拆分数据包,拥有分类数据包的功能,最后通过可视化界面显示给用户。     

Windows平台下数据采集串口通讯的实现

讨论了 32位Windows操作平台下 ,运用多线程和面向对象方法 ,开发数据采集领域的串口通讯模块的相关技术 ,对其他领域的串口通讯也有启发。最后给出了模块的应用实例     

分布式星群网络中基于蚁群算法的通信量分类路由

给出了一种分布式星群网络(Distributed Satellite Cluster Network,DSCN)体系架构,阐明了DSCN拓扑变化的特点。在分析网络状态获取方式和路由计算方法的基础上,提出了一种适用于DSCN的基于蚁群算法的通信量分类路由(Ant Colony Optimization Based Traffic Classified Routing,ATCR)算法。ATCR算法将通信量分为时延敏感型通信量A、带宽敏感型通信量B以及提供尽力而为服务的通信量C,并对蚁群算法(Ant Colony Optimization,ACO)收敛慢的缺点进行了改进。仿真实验表明,ATCR算法提高了收敛速度,可以有效平衡网络流量。通信量A和C的端到端时延要小于未采用通信量分类的改进ACO算法。由于减少了重负载链路的数量及拥塞引起的丢包,ATCR算法在分组递交率上的表现优于改进的ACO算法。     

Class Tester:一个基于状态转换的类测试工具的设计与实现

面向对象软件测试的类测试方法有三种:基于规约说明的类测试方法、基于类流图的类测试方法、基于状态转换的类测试方法.本文描述了一个针对C 语言的基于状态的类测试工具的设计和实现,介绍了该工具的体系结构和主要算法.对测试驱动器的自动生成的方法作了详细介绍.最后通过一个实例描述了该工具的工作流程.     

On the Semantics of Associations and Association Ends in UML

Association is one of the key concepts in UML that is intensively used in conceptual modeling. Unfortunately, in spite of the fact that this concept is very old and is inherited from other successful modeling techniques, a fully unambiguous understanding of it, especially in correlation with other newer concepts connected with association ends, such as uniqueness, still does not exist. This paper describes a problem with one widely assumed interpretation of the uniqueness of association ends, the restrictive interpretation, and proposes an alternative, the intentional interpretation. Instead of restricting the association from having duplicate links, uniqueness of an association end in the intentional interpretation modifies the way in which the association end maps an object of the opposite class to a collection of objects of the class at that association end. If the association end is unique, the collection is a set obtained by projecting the collection of all linked objects. In that sense, the uniqueness of an association end modifies the view to the objects at that end, but does not constrain the underlying object structure. This paper demonstrates how the intentional interpretation improves expressiveness of the modeling language and has some other interesting advantages. Finally, this paper gives a completely formal definition of the concepts of association and association ends, along with the related notions of uniqueness, ordering, and multiplicity. The semantics of the UML actions on associations are also defined formally     

基于切换频率的分层可靠移动IP组播研究*

从以切换频率区分移动节点类别的角度,提出了一种新的可靠移动IP组播方案,目的是让不同类别的移动节点都能得到相应的、接近最佳的可靠组播服务.与现有的可靠移动IP组播协议相比,提出了基于移动节点的切换频率对移动节点进行分类的概念;提出了对不同类别的移动节点分别使用相应的可靠移动IP组播协议的思想;根据上述思想改进了RRBMoM协议,得到了新协议--ARRBMoM协议.在此基础上,利用OPNET分别模拟ARRBMoM和RRBMoM协议的运行情况,对其性能进行了分析和比较.仿真结果表明了ARRBMoM协议在多种速度类别的移动节点同时存在时,以及移动节点运动速度较快时,比RRBMoM协议在组播树重构、端到端延时、重传率、丢失率等方面具有更好的性能.     

Naked singularity formation in generalized Vaidya space-time

The gravitational collapse in generalized Vaidya space-time is considered. It is known that the end state of gravitational collapse, as to whether a black hole or a naked singularity is formed, depends on the mass function M(v, r). Here we give conditions for the mass function which correspond to the equation of the state P = αρ. where α ∈ (0, 1/3], and according to these conditions we obtain either a black hole or a naked singularity as the end state of gravitational collapse. We also give the conditions for the mass function under which the singularity is gravitationally strong. We present simple examples showing when the result of gravitational collapse is a naked singularity and when this singularity is strong.     

Decorating tokens to facilitate recognition of ambiguous language constructs

Software tools are fundamental to the comprehension, analysis, testing and debugging of application systems. A necessary first step in the development of many tools is the construction of a parser front‐end that can recognize the implementation language of the system under development. In this paper, we describe our use of token decoration to facilitate recognition of ambiguous language constructs. We apply our approach to the C++ language since its grammar is replete with ambiguous derivations such as the declaration/expression and template‐declaration/expression ambiguity. We describe our implementation of a parser front‐end for C++, keystone, and we describe our results in decorating tokens for our test suite including the examples from Clause Three of the C++ standard. We are currently exploiting the keystone front‐end to develop a taxonomy for implementation‐based class testing and to reverse‐engineer Unified Modeling Language (UML) class diagrams. Copyright © 2002 John Wiley & Sons, Ltd.     

Identification of variable spacial coefficients for a beam equation from boundary measurements

We consider a system described by the Euler-Bernoulli beam equation, with one end clamped and with torque input at the other end. The output function are the displacement and the angle velocity at the non-clamped end of the beam. We study the identification of the spatially variable coefficients in the beam equation, from input-output data. We show that both the density and the flexural rigidity of the beam (which are assumed to be of class C⁴) can be uniquely determined if the input and output functions are known for all positive times.     

Turbulent Flow in the Vicinity of Side Weirs in Subcritical Conditions

Side weirs are installed on the main channels wall in sewage disposal systems and irrigation networks to divert the flow. In this paper, the flow pattern in rectangular channels along a side weir is predicted using the Volume of Fluid (VOF) scheme and the standard k–ε and RNG k–ε turbulence models. A comparison between the numerical and experimental results shows the high accuracy of the numerical model. For example, the values of root mean square error (RMSE), mean absolute relative error (MARE) and correlation coefficient (R) for the lateral velocity on z = 0.183 m level are calculated 3.782, 0.399 and 0.993, respectively. According to the simulation results, as the flow approaches to the side weir plane the flow field pressure decreases suddenly and at the end of the side weir the pressure increases. Also, by advancing the flow towards the downstream of the side weir the turbulent kinetic energy of the flow within the rectangular channel decreases. For all levels, the turbulent length scale value suddenly increases by reaching the flow to the end of the side weir.     

Calculation of melatonin and resveratrol effects on steatosis hepatis using soft computing methods

In this work, beneficial effects of melatonin and resveratrol drugs on liver damage in rats, induced by application of acute and chronic carbon tetrachloride (CCl₄) have been examined. The study consists of three main stages:

• (1)Data acquisition: light microscopic images were obtained from 60 rats separated into 10 groups after the preparation of liver tissue samples for histological examination. Rats in first five experimental groups for the four-day and the other five groups for twenty-day were examined.
• (2)Data processing: by the help of histograms of oriented gradient (HOG) method, obtaining low-dimensional image features (color, shape and texture) and classifying five different group characteristics by using these features with artificial neural networks (ANNs), and support vector machines (SVMs) have been provided.
• (3)Calculation of drug effectiveness: firstly to determine the differences between group characteristics of rats, a pilot group has been selected (diseased group-CCl4), and the responses of ANN and SVM trained by HOG features have been calculated.

As a result of ANN, it has been seen that melatonin and resveratrol drugs have %65.62–%75.12 positive effects at the end of the fourth day, %84.12–%98.89 positive effects on healing steatosis hepatis at the end of the twentieth day respectively and as a result of SVM, it has been seen that melatonin and resveratrol drugs have %62.5–%68.75 positive effects at the end of the fourth day, %45.12–%60.89 positive effects on healing steatosis hepatis at the end of the twentieth day respectively.