A Model‐Based Analysis of Secure Video Transmission Based on IPSec and IPv4

A promising solution to protect wired Internet networks is to use the Secure Internet Protocol (IPSec); however, this has some drawbacks, particularly on the quality of service (QoS). This paper aims at evaluating the video traffic QoS in terms of end‐to‐end delay and packet loss rate. Based on some basic assumptions, our analysis shows that the performance with IPSec is rapidly inferior to the IPv4 performance. We thus suggest adding some QoS parameters into IPSec in order to achieve a compromise between QoS and security.     

基于 CBR SWC模型的 VOC框架模板生成技术研究

虚拟原型逼真设计作为虚拟产品开发研究的一个方面，是近几年发展起来的新技术，主要研究虚拟环境下的产品建模问题以及基于仿真的集成产品和过程设计问题。智能支持的计算机辅助VOC荻取与分析综合工具是虚拟原型逼真设计模型实现的重要模块之一，这里研究了顾客需求(VOC)荻取和综合分析工具实现的关键技术，着重论述了基于事例推理的加权相似性计算(CBR-WSC)模型的VOC框架自动生成技术，给出了模型的结构、算法步骤，结合仪表产品应用实例验证了模型的有效性。     

基于自适应变论域模糊理论的CBR视频码率控制策略

针对H.264/AVC视频编码码率控制算法复杂度高的问题,提出了一种在CBR环境下采用自适应变论域模糊理论、辅以视频质量控制、编码控制和主动跳帧技术的码率控制方法,降低了算法的复杂度,提高了控制精度.仿真测试结果表明,该方法在保证CBR输出码率精度的条件下,与JVT-G012的方法相比,降低了算法复杂度,提高了重建视频图像质量,是一种有效的码率控制策略.     

On delay constrained CAC scheme and scheduling policy for CBR traffic in IEEE 802.11e wireless LANs

CBR (constant bit rate) traffic is expected to be an important traffic source in wireless networks. Such sources usually have stringent jitter or delay requirements and in many cases they should be delivered exactly as they were generated. In this paper, we propose a strictly guaranteed QoS (quality‐of‐service) provisioning CAC (call admission control) scheme with a polling‐based scheduling policy for CBR traffic in IEEE 802.11e wireless LANs. Under such a scheme, the proposed transmit‐permission policy for HCCA (HCF controlled channel access) method can forecast the maximum suffered delay for each packet and derive sufficient conditions so that all the CBR sources satisfy their time constraints to provide deterministic QoS guarantees. A simple analytical model is carried out to estimate the average queueing delay of the proposed scheme. In addition to theoretical analysis, simulations are conducted to validate its promising performance. Our simulation results show that the proposed scheme maintains a high throughput with respect to the whole range of system load. Copyright © 2009 John Wiley & Sons, Ltd.     

路邦土壤固化剂固化土的工程性质试验

采用的路邦EN-1型土壤固化剂是一种高分子化学土壤固化剂。它的固化原理是:与水稀释后,可与土壤中的矿物质及土壤颗粒发生溶解、结晶、吸收、扩散、再结晶的链式化学反应,从而将路基凝结成整体结实、持久的板体结构,显著降低路基弯沉,提高路基回弹模量,提高路基密实度,增强路基的承载能力,并显著改善路基的水稳性。通过试验,对土壤的干密度稍有提高;无侧限抗压强度及承载比(CBR)明显提高;不同龄期浸水的无侧限抗压强度随龄期增加而增加。     

Integration of fault diagnosis based on case-based reasoning principles in brewing

In this paper we describe an approach to Sensor Fault Detection, Isolation and Accommodation (SFDIA) that is mainly based on fuzzy processing of deviation from the model predictions. The predictive model is supported using a Decision Making Unit (DMU) and cased-based Reasoning principles (CRB) where pass cases are saved and filed in the Library for confirmed solution and repaired cases. This tool uses the sensor readings at the current time step to predict system state at the next time step using observers. Although the method lacks the mathematical basis that other analytical methods provide; this method is simple effective and useful.     

基于CBR和遗传算法的模具智能CAD系统

在分析和总结当前智能设计方法的基础上，采用CBR与遗传算法这两种智能技术，用C Builder和SQL Server开发了一个模具智能CAD系统，集成人机智能进行模具结构方案优化设计。     

基于遗传算法的事例改写策略在注塑模成本评估CBR系统中的应用研究

注塑模成本评估是一个涉及多方面合作的问题，将基于事例的推理(CBR)技术用于注塑模成本评估过程中。针对成本评估过程中的弱理论性，提出基于遗传算法的事例改写策略。提出了算珐的关键技术，并提出了利用三级模式事例改写模型，构造合适的适配值函数，未解决注塑模成本评估CBR系统事例改写的原理和方法。     

基于事例推理技术的涡轮叶片精铸模分模设计研究与应用

飞机发动机涡轮叶片的内部结构相当复杂，这给叶片模具的分模设计带来了很大的困难。通过对传统手工分模设计过程的分析，并针对分模设计经验依赖性强的特点，指出基于事例推理的分模设计方法的可行性，构建了基于事例推理的涡轮叶片分模设计系统框架，解决了分模设计的分模知识提取、分模事例描述、分模事例检索、分模事例修改等关键问题。最后给出了系统运行实例，表明能够提高设计效率，减少设计难度。     

基于CBR的机械产品模块化设计方法的研究

提出在模块化设计中模块对设计需求的适应性问题 ;论述了 CBR技术同模块化设计的关系 ,研究了基于实例的模板创建方法以及专家知识集成于设计模板的策略 ;分析液压机典型结构 ,创建模板实例及参数化的机身CAD模型 ;构造参数化设计的专家知识系统 ,实现知识的查询、提取、更新和基于知识的参数驱动机制