提出了一种基于应用层的安全保密IP电话QoS保障方案并实现.在语音加解密过程中,通过多缓冲区的合理设置和加密模式的设计,降低了时延和带宽.针对网络丢包问题,提出了一种改进的错误隐藏技术,并与前向纠错技术集成应用,较好地完成了丢失包的恢复.采用自适应播放延迟方法,解决了时延抖动所导致的语音播放不流畅问题.在模拟发生包丢失和包错序的网络环境中进行了测试,IP电话在满足安全保密通信的前提下,时延、带宽和丢包率等指标都达到了商用电话的标准,具有较强的实用性.

针对现有的机载激光雷达产品测试系统不能模拟特定信噪比,且系统使用复杂的问题,开发了基于USB总线的机载多脉冲激光雷达产品测试系统;测控软件可以设定信噪比、脉冲幅值、脉冲周期等参数,并根据静态测距和动态测距的实际需要,生成静态和动态模拟数据;另外,测试系统还能够采集外场数据,并在测控计算机上存储和分析;采集和生成的数据经过USB总线发送给基于FPGA+高速D/A转换器架构的数据转换器,再输出给激光雷达产品,保证了数据传输的高速性和灵活性;经过测试表明,信噪比在3~9的情况下,产生回波信号的距离误差控制在1%以内,信号幅值误差控制在0.5%以内;测试系统的各项指标都满足实际需要,为激光雷达产品调试提供了良好的模拟仿真平台。

针对农业大棚作物生长环境参数精确控制和信息化管理的需求,基于SSH框架和模糊控制,设计并实现了精准农业大棚智能监控平台.采用B/S体系结构模型,设计了系统框架,采用Socket和多线程技术,实现了与多个大棚的数据通信.提出了一种基于温度、湿度、CO2浓度和光照度4个参数的模糊控制器,实现大棚内环境参数的自动调节.试验结果表明,温度、湿度、CO2浓度、光照度的变化均控制在合适的范围内,保证了作物的生长环境需求.平台运行稳定,执行设备控制响应时间在800 ms以内,采集时间在300 ms以内,具有一定的实用性、安全性和可维护性,有效实现了农业大棚环境参数的精准控制和远程操作,为精准农业实施提供了保障.

基于室外消光比方法,完成了机载多脉冲激光雷达性能综合测试系统的研制;该系统由测控软件、便携式检测仪、能量计和光学设备等组成;测试软件基于Visual C++开发,采用串口通信技术和多线程技术,使系统具有较好的稳定性和可靠性;采用自动控制转盘式光阑的方法,提高了系统的实用性;试验结果表明:所研制的系统可实现对多脉冲激光雷达多个主要性能参数的精确测试,有利于激光雷达性能综合测试的自动化,为产品的批量生产提供有效的检测手段。

pectral clustering comes from operator theory and is able to efficiently decrease data dimension and classify data.However,current domestic researches pay more attention to applied algorithm design,and there is lack of theoretical outcome.In order to make up the shortcomings in theory,this paper systematically summaries the theory of spectral clustering,pays more attention to study the newest foreign operator theory research achievements.Besides,we briefly discuss and analyze some specific spectral clustering algorithms.We introduce and analyze the principle,convergence,current status of spectral clustering and its inherent association with manifold learning in terms of integral operator,spectral graph theory and manifold learning.At last,we suggest some possible directions.

Using image processing techniques,it is analysed the relation of the dose and the flocculation image characteristic parameters with equivalent diameter,the fractal dimension and concentration in the process of waster water treatment.Considering the dosing control of the actual operating environment and the real time requirement,Retinex algorithm is used to solve the uneven light phenomena,small amount of calculation algorithm are also used in image processing.The analyzed results show that the actual automatic control is better practicability.

This paper designs one type of system of acquisition for farm land image based on GPRS and ARM processor S3C2410.In this system,image information are obtained by CMOS image sensors and data are transferred by GPRS business of GSM between the remote image terminals and the center of monitoring,which can meet high reliability of image acuqusition,reduce communication expense for image transmission and guarante system strong scalability.

[Objective]This paper aimed at studying the liquefaction technology of chestnut shells [Method]Effects on chestnut shells liquefaction of six catalysts were studied,which were sodium hydroxide,sodium carbonate,acetic acid(99.5%),phosphoric acid(85%),hydrochloric acid(37%),sulfuric acid(98%).The research had analyzed the liquefaction effects of chestnut shells in presence of phenol and at liquefaction temperatures of 130,150 and 170 ℃,in which the proportion of added quantities of concentrated sulfuric acid,phosphoric acid,concentrated hydrochloric acid to phenol were 1%-6%.Properties of phenolic resin made from formaldehyde and phenol-liquefied products of chestnut shells catalyzed by concentrated sulfuric acid with an added amount of 4% at 150 ℃(WPF)were analyzed and compared with traditional phenolic formaldehyde resin(PF).[Result]Acid catalysts were better than alkaline ones in the phenol-liquefaction of chestnut shells,and the liquefaction ratio increased with the increasing of acidic intensity.The liquefaction ratio had attained the maximum as 92.11 % when catalyzed by concentrated sulfuric acid with an added amount of 4% at 150 ℃.The phenolic resin made from the liquefied products of chestnut shells was basically in accordance with the standard of GB/T 14732-93 when the mass ratio of chestnut shells powders to phenol was 1∶3.[Conclusion]It was possible to produce phenolic resin with liquefied chestnut shells.

With an immense population base,the agricultural population of Henan Province grew rapidly. And There are also problems in the quality and structure of population that should not be neglected. The land,water and other natural resources could not be made fully use and were contaminated seriously. These havoc the agroecological environment in Henan Province. Striking improvements in the agricultural ecological environment and accelerating the development of the agroecological environment assort with the agricultural population and resources,Henan Province must face four ways:control the population growth and improve the quality of science and technology of the agricultural workers; promote green agricultural technology and protect agricultural resources; develop integrated - culture eco - engineering and recycle the biomass resources with reason; improve environment protection mechanisms and enhance the control of agroecological environment.

介绍一种基于PC to PC模式VOIP的安全方案,着重解决IP电话安全保密通信过程中的身份认证、密钥协商和语音加密问题,并采取措施减小了语音加密对QoS的影响。关键词：IP电话;身份认证;密钥协商;语音加密

本文介绍了通过VHDL硬件描述语言对FPGA器件进行编程,实现单片机的打印机、键盘、显示器等I/O接口和随机存储器RAM的扩展,把复杂的接口逻辑封装在一块FPGA上。

本文介绍了葡萄糖加氢生产山梨醇用钌催化剂的国内外研究现状,提出了该催化剂的发展趋势。

虹膜图像异常区域分割是虹膜诊断的关键。由于虹膜图像纹理丰富,很多图像分割方法无法取得有效的分割结果。文中采用改进流域变换算法,有效地对虹膜图像进行分割,并避免了传统流域变换存在的过分割问题。试验结果表明,改进流域变换分割虹膜图像异常区域,精确地提取出了异常区域边缘,且无需分割后的区域合并处理,降低了分割的复杂性。