基于ATmega 128单片机的数字化地下管线定位仪

地下管线被视为城市的生命线。分析了地下管线定位仪的基本原理,并在此基础上详细介绍了基于ATmega 128单片机的数字化地下管线定位仪的硬件实现和软件实现,重点分析了基于磁保持继电器的分时供电电源电路。ATmega 128单片机实现了地下管线定位仪的数字化,使得定位仪能快速、准确地对地下管线进行水平定位和垂直定深。     

注塑机注射速度的模型预测迭代学习控制

针对注射过程具有重复运行和非线性的特性,在对预测控制与迭代学习控制进行综合应用并加以改进的基础上,给出一种模型预测迭代学习复合控制新算法,研究了控制器的设计方案.同时,将迭代学习思想引入到预测步长的在线调整,提出了预测步长的迭代学习方法.仿真结果表明,该方法是有效的,其控制性能优于PID迭代学习控制系统.     

A piecewise analysis method to stability analysis of linear continuous/discrete systems with time‐varying delay

The delay‐dependent stability problem of linear continuous/discrete systems with time‐varying delay is investigated based on a piecewise analysis method (PAM). In the method, the variation interval of the time delay is firstly divided into several subintervals. By checking the variation of the Lyapunov functional in every subinterval, some new delay‐dependent stability criteria are derived. Several numerical examples show that our method can lead to much less conservative results than those in the existing references. Moreover, when the number of the divided subintervals increases, the corresponding criteria can provide an improvement on the results. Copyright © 2008 John Wiley & Sons, Ltd.     

Design of a Scalable Multicast Scheme With an Application-Network Cross-Layer Approach

This paper develops an efficient and scalable multicast scheme for high-quality multimedia distribution. The traditional IP multicast, a pure network-layer solution, is bandwidth efficient in data delivery but not scalable in managing the multicast tree. The more recent overlay multicast establishes the data-dissemination structure at the application layer; however, it induces redundant traffic at the network layer. We propose an application-oriented multicast (AOM) protocol, which exploits the application-network cross-layer design. With AOM, each packet carries explicit destinations information, instead of an implicit group address, to facilitate the multicast data delivery; each router leverages the unicast IP routing table to determine necessary multicast copies and next-hop interfaces. In our design, all the multicast membership and addressing information traversing the network is encoded with bloom filters for low storage and bandwidth overhead. We theoretically prove that the AOM service model is loop-free and incurs no redundant traffic. The false positive performance of the bloom filter implementation is also analyzed. Moreover, we show that the AOM protocol is a generic design, applicable for both intra-domain and inter-domain scenarios with either symmetric or asymmetric routing.     

Large-scale network intrusion detection based on distributed learning algorithm

As network traffic bandwidth is increasing at an exponential rate, it’s impossible to keep up with the speed of networks by just increasing the speed of processors. Besides, increasingly complex intrusion detection methods only add further to the pressure on network intrusion detection (NIDS) platforms, so the continuous increasing speed and throughput of network poses new challenges to NIDS. To make NIDS usable in Gigabit Ethernet, the ideal policy is using a load balancer to split the traffic data and forward those to different detection sensors, which can analyze the splitting data in parallel. In order to make each slice contains all the evidence necessary to detect a specific attack, the load balancer design must be complicated and it becomes a new bottleneck of NIDS. To simplify the load balancer this paper put forward a distributed neural network learning algorithm (DNNL). Using DNNL a large data set can be split randomly and each slice of data is presented to an independent neural network; these networks can be trained in distribution and each one in parallel. Completeness analysis shows that DNNL’s learning algorithm is equivalent to training by one neural network which uses the technique of regularization. The experiments to check the completeness and efficiency of DNNL are performed on the KDD’99 Data Set which is a standard intrusion detection benchmark. Compared with other approaches on the same benchmark, DNNL achieves a high detection rate and low false alarm rate.     

研究生计算机网络课程体系研究与实践

本文研究面向研究生的计算机网络课程体系,包括教学内容和教学方法等。在计算机网络课程的教学实践中,以专题研究组织教学内容,将教学活动分解为相辅相成的三个环节:授课和阅读,课程设计,以及研讨环节。同时,将理论性教学和实践性教学有机结合。教学实践表明,将科研素养的培养融合在课程教学过程中,有助于培养学生在计算机网络领域的研究和创新能力。     

先秦儒、道、墨——中国传统设计美学思想之渊源

代表着先秦诸子百家文化中的儒、墨、道,三者对美学的感悟是中国传统设计美学思想的源头活水。儒家美学的中和之美,道家美学的无为之美,墨家美学的实用之美,交织形成了内容丰富而独特的中国传统设计美学思想体系。     

嵌入式操作系统的时钟机制的研究

在实时操作系统中,无论是实时响应并处理来自各个被控对象的实时信息,还是对任务执行时间的管理、资源的限时等待等,都需要时钟的参与。因此,准确而又具有足够精度的时钟对于实时系统是必不可少的。根据普通嵌入式系统内核中的时钟机制的特点,分析了实时操作系统中的有关时钟机制改进的具体方法与特点,并提出了三种多粒度时钟机制：UTIME机制、RFRTOS TIMER机制、RTOS KERNEL TIMER机制,并且分析了与时钟机制密切相关的中断服务程序。     

曼彻斯特编码技术在测井数据传输中的应用研究

基于曼彻斯特码编码技术文章提出一种适用于石油测井下行数据传输链路的设计方案。采用Verilog HDL设计的曼彻斯特编、译码器,在ALTERA公司的QuartusⅡ6．0软件平台上完成了仿真,并在FPGA器件上实现了硬件测试．最后下行数据传输链路的发送端和接收端在6km的电缆模拟器上完成了系统测试。通过计算机仿真和工程实现验证了该设计方法的正确性和实用性。     

从艺术设计教育中存在的问题看工作室制度的实施

艺术设计教育近年来蓬勃发展的同时出现了很多问题.本文主要谈了课程结构程式化以及教学与实践严重脱节的问题,同时分析了工作室制度的起源、影响。提出了可以实施工作室制度来解决这些问题的思想与方法.