同侧双滚子从动件盘形凸轮轮廓的解析设计法

文中采用同侧双滚子从动件结构设计了新型形锁合盘形凸轮机构;采用解析算法之包络原理生成了双滚子从动件盘形凸轮的内外轮廓,并通过算例具体介绍了凸轮轮廓包络原理生成法的计算机实现过程。     

基于面向对象和超媒体技术的CAI系统的研究

从面向对象的观点出发，提出了一个ＣＡＩ（计算机辅助教学）系统的模型，该模型可以描述已有的和正在的智能ＣＡＩ系统，最后给出了在超媒体环境下ＣＡＩ系统设计的思考。     

频谱仪测量邻道功率比动态范围的研究

频谱分析仪几乎是目前测量邻道功率比（ＡＣＰＲ）的唯一有效工具。ＡＣＰＲ是影响通信系统容量及电磁兼容性的重要技术指标，也一直是各级无线电管理机构进行无线电发射设备管理及检测的一个重要内容。怎样利用频谱仪固有的参数并结合被测信号的特点从理论上确定频谱仪对应的ＡＣＰＲ最大测试动态范围，对各级无线电管理机构来说有一定的技术指导意义。由于涉及到的理论较多，限于篇幅，本文不做太多的理论推导而直接给出结果。一、频谱仪测量ＡＣＰＲ的原理探讨频谱仪测量ＡＣＰＲ的原理，主要是弄清有关ＡＣＰＲ的概念。ＡＣＰＲ（Ａｄｊ…     

单基板彩色AC—PDP放电单元的二维数值模拟

介绍了基于粒子流运动连续方程建立的二维单基板彩色ＡＣ－ＰＤＰ放电单元的数值计算模型，该模型包括混合气体中的电子，离子，激发态分子等１５种基本粒子，描述了粒子的反应，迁移和扩散过程，通过模拟单基板彩色ＡＣ－ＰＤＰ放电单元的工作情形，给出了单元内电位，电子和离子浓度的分布情况。     

千瓦级CO激光器分子振动态布局分布及输出特性的计算

用一维动力学模型对千瓦级模流自持放电ＣＯ激光器工作特性进行了计算，得到了Ｃ烽Ｎ２分子的振动态布居，利用常数增益光强平均法计算了三程Ｎ形折叠腔的输出功率的温度特性及谱线分布情况，得到了振转过激光输出的振动带及转动支线的详细情况，理论计算与实验结果基本一致。     

发展中的CATV系统

发展中的ＣＡＴＶ系统何淑贞一、ＣＡＴＶ由来及其特点ＣＡＴＶ是ＣｏｍｍｕｎｉｔｙＡｎｌｅｎｎａＴＶ的简称。４０年代为解决美国山村接收广播电视图像的质量问题，人们在接收电视信号好的地段架设天线，把接收到的信号传递给电视用户。由多个用户共用一付天线，这就形...     

望远镜谐振腔在高功率化学氧碘激光器上的应用

分析和实验研究了腔内放置的望远镜在高功率化学氧碘激光器上降低输出光束发散的应用，基于ＡＢＣＤ矩阵理论建立了一套用于分析望远镜谐振腔的理论公式，以放大倍数在２－４间的伽利略望远镜和我们的化学氧碘高功率激光器作为分析模型进行了理论计算。将望远镜放大光轴上适当位置，整个望远镜谐控腔就能方便地装到该模型激光器上，该激光器输出光束的发散和腔的稳定即能同时得到改善，在计算的一种条件下了实验研究，测得的发散角和     

具有GRIN—SCH量子阱结构激光器光波导及光场特性分析

本文给出了具有ＧＲＩＮ－ＳＣＨ结构量子阱激光器的光波导模型和详细的数值计算方法,并计算分析了ＡｌｘＧａ１－ｘＡｓＧＲＩＮ层中Ａｌ浓度和ＧＲＩＮ层厚度对等效折射率的影响,给出了ＧＲＩＮ层厚的最佳值范围;给出了宽接触ＩｎＧａＡｓ／ＡｌＧａＡｓＧＲＩＮ－ＳＣＨ量子阱激光器的近场分布三维图形,并由近场分布通过快速傅里叶变换求出了远场分布。计算得到的近、远场分布图形与实际器件测试得到的结果相符合。     

一种新的VBR视频业务理论分析模型

目前没有一个理论分析模型可以描述Ｇａｍｍａ分布以及负指数下降的自相关性质，而这些性质对视频业务模型是很重要的。本文在ＤＡＲ（１）模型的基础上发展出一种适合理论分析的视频业务模型Ｃ－ＤＡＲ（１）。它是一个符合视频业务Ｇａｍｍａ分布及自相关特点的分析模型。文中同时指出了一条将离散时间马氏链模型转化为连续时间马氏链的途径。     

非均匀CSMA/CD光纤总线LAN的性能分析

作为尝试，以ＣＳＭＡ／ＣＤ光纤总线ＬＡＮ为对象，应用排队服务理论，对非均匀网络环境下的系统模型进行了数学解析和评价，推导出网络性能的重要参数利用率的计算公式，并通过ＧＰＳＳ仿真对数学模型进行了初步验证，获得了满意结果。     

Research on the Propagation Models and Defense Techniques of Internet Worms

Internet worm is harmful to network security,and it has become a research hotspot in recent years.A thorough survey on the propagation models and defense techniques of Internet worm is made in this paper.We first give its strict definition and discuss the working mechanism.We then analyze and compare some repre-sentative worm propagation models proposed in recent years,such as K-M model,two-factor model,worm-anti-worm model（WAW）,firewall-based model,quarantine-based model and hybrid benign worm-based model,etc.Some typical defense techniques such as virtual honeypot,active worm prevention and agent-oriented worm defense,etc.,are also discussed.The future direction of the worm defense system is pointed out.     

物联网恶意代码传播模型研究

Nowadays, the main communication object of Internet is human-human. But it is foreseeable that in the near future any object will have a unique identification and can be addressed and connected. The Internet will expand to the Internet of Things. IPv6 is the cornerstone of the Internet of Things. In this paper, we investigate a fast active worm, referred to as topological worm, which can propagate twice to more than three times faster than a traditional scan-based worm. Topological worm spreads over AS-level network topology, making traditional epidemic models invalid for modeling the propagation of it. For this reason, we study topological worm propagation relying on simulations. First, we propose a new complex weighted network model, which represents the real IPv6 AS-level network topology. And then, a new worm propagation model based on the weighted network model is constructed, which describes the topological worm propagation over AS-level network topology. The simulation results verify the topological worm model and demonstrate the effect of parameters on the propagation.     

Encounter-based worms: Analysis and defense

An encounter-based network is a frequently disconnected wireless ad hoc network requiring immediate neighbors to store and forward aggregated data for information disseminations. Using traditional approaches such as gateways or firewalls to deter worm propagation in encounter-based networks is inappropriate. We propose a worm interaction approach that relies upon automated beneficial worm generation to alleviate problems of worm propagations in such networks. To understand the dynamics of worm interactions and their performance, we mathematically model worm interactions based on major worm interaction factors, including worm interaction types, network characteristics, and node characteristics using ordinary differential equations and analyze their effects on our proposed metrics. We validate our proposed model using extensive synthetic and trace-driven simulations. We find that all worm interaction factors significantly affect the pattern of worm propagations. For example, immunization linearly decreases the infection of susceptible nodes, while on–off behavior only impacts the duration of infection. Using realistic mobile network measurements, we find that encounters are “bursty”, multi-group, and non-uniform. The trends from the trace-driven simulations are consistent with the model, in general. Immunization and timely deployment seem to be most effective in countering worm attacks in such scenarios, while cooperation may help in a specific case. These findings provide insight that we hope would aid in the development of counter-worm protocols in future encounter-based networks.     

Using signal processing techniques to model worm propagation over wireless sensor networks

This paper describes how a topologically aware worm propagation model (TWPM) for wireless sensor networks is formulated and derived. The paper defines worm propagation characteristics that are specific to sensor networks. It also parameterize the effects of physical channel conditions, medium access control (MAC) layer contention, network layer routing, and transport layer protocol on worm propagation in sensor networks. The basic model formulation results in a partial differential equation, which is solved in the frequency domain to yield a closed-form solution for the TWPM. It is shown that in the spatial domain, the TWPM spread function is low-pass filtered by a two-dimensional isotropic Gaussian filter, thereby providing an intuitive feel for the dependence of the model on its underlying parameters. Simulation results demonstrate that the TWPM provides an effective and accurate worm propagation model for sensor networks     

Modeling and analysis of Internet worm propagation

Although the frequency of Intemet worm's outbreak is decreased during the past ten years,the impact of worm on people's privacy security and enterprise's efficiency is still a severe problem,especially the emergence of botnet.It is urgent to do more research about worm's propagation model and security defense.The well-known worm models,such as simple epidemic model (SEM) and two-factor model (TFM),take all the computers on the internet as the same,which is not accurate because of the existence of network address translation (NAT).In this paper,we first analyze the worm's functional structure,and then we propose a three layer worm model named three layres worm model (TLWM),which is an extension of SEM and TFM under NAT environment.We model the TLWM by using deterministic method as it is used in the TFM.The simulation results show that the number of NAT used on the Intemet has effects on worm propagation,and the more the NAT used,the slower the worm spreads.So,the extensive use of NAT on the Internet can restrain the worm spread to some extent.     

P2P触发式主动型蠕虫传播建模

对P2 P触发式主动型蠕虫的攻击机制进行了研究,发现该类蠕虫传播通常包括四个阶段：信息收集,攻击渗透、自我推进与干预激活。基于对P2 P触发式主动型蠕虫攻击机制的分析并运用流行病学理论提出了P2 P触发式主动型蠕虫传播数学模型并基于该模型推导了蠕虫传播进入无蠕虫平衡状态的充分条件。仿真实验验证了所提出传播模型的有效性。     

Modeling and analysis of Intemet worm propagation

Although the frequency of Internet worm's outbreak is decreased during the past ten years, the impact of worm on people's privacy security and enterprise's efficiency is still a severe problem, especially the emergence of botnet. It is urgent to do more research about worm's propagation model and security defense. The well-known worm models, such as simple epidemic model (SEM) and two-factor model (TFM), take all the computers on the internet as the same, which is not accurate because of the existence of network address translation (NAT). In this paper, we first analyze the worm's functional structure, and then we propose a three layer worm model named three layres worm model (TLWM), which is an extension of SEM and TFM under NAT environment. We model the TLWM by using deterministic method as it is used in the TFM. The simulation results show that the number of NAT used on the Internet has effects on worm propagation, and the more the NAT used, the slower the worm spreads. So, the extensive use of NAT on the Internet can restrain the worm spread to some extent.     

Internet worm early detection and response mechanism

In recent years, fast spreading worm has become one of the major threats to the security of the Internet and has an increasingly fierce tendency.In view of the insufficiency that based on Kalman filter worm detection algorithm is sensitive to interval, this article presents a new data collection plan and an improved worm early detection method which has some deferent intervals according to the epidemic worm propagation model, then proposes a worm response mechanism for slowing the wide and fast worm propagation effectively.Simulation results show that our methods are able to detect worms accurately and early.     

模型检验下蠕虫病毒检测器的设计与实现

现在蠕虫病毒检测技术主要是基于病毒特征库,通过特征码的匹配来确定。这种方法的主要缺点是病毒特征库的更新总是滞后于病毒的发布,实时性效果较差。这里提出了一种新的方法,采用模型检验技术的方法,结合蠕虫病毒的入侵原理,改进计算逻辑树的规范设计,从汇编代码层面对蠕虫病毒行为进行特征提取,有效建模,实验结果显示这种方法能够有效地检测蠕虫病毒及其变种。     

基于FSA ACO混合改进算法的蜗轮蜗杆故障识别

针对蜗轮蜗杆故障诊断问题,提出基于FSA ACO混合改进算法的蜗轮蜗杆故障识别的研究方法。该方法提出了FSA ACO混合改进策略,在谋求一个优势互补的基础上,对算法相关参数优化。同时针对该算法与蜗轮蜗杆故障识别结合构建算法模型问题,提出利用近邻函数准则作理论桥梁策略,寻找一种新的基于FSA ACO混合算法的蜗轮蜗杆故障诊断技术研究方法。以WPA40型号的蜗轮蜗杆为测试对象,验证了该研究方法的可行性和有效性。