蒸汽在水下有限空间内喷注时喷注噪声的声源分析

在实验研究的基础上，用计算流体力学软件(CFD)对与喷注噪声密切相关的压力场与温度场进行数值计算，定量分析了在不同温度时所对应的压力场与喷注噪声的关系。     

时频混合重叠复用系统的快速检测算法

为提高通信系统的频谱效率,研究了一种时频混合重叠复用系统,并提出针对该系统的基于Gabor变换的快速检测算法和利用误差反向传播思想的改进检测算法。实验结果表明,与利用最大似然序列估计检测算法相比,该算法在牺牲部分性能的条件下,检测速度大幅提高,且系统性能和检测速度做了很好的折衷,在较高信噪比时仍然优于相同频谱效率的高阶调制。采用相互重叠的信号复用传输方式直接提高传输速率比使用同样频谱效率的高阶QAM调制能带来更大的增益。     

一种基于网格剖分的两点射线追踪方法

两点射线追踪是解决复杂地质结构下反射波射线正演的有效方法。在初至波层析射线追踪算法基础上，提出了一种两点射线追踪方法，利用层析网格对模型进行离散化，通过两阶段法射线追踪，分别对激发点和接收点按向前处理过程计算模型单元及节点的旅行时，两次时间相加作为最小旅行时，再在目的层界面邻域扫描最小旅行时子震源网格单元，用粒子群算法在该单元内扫描全局最小旅行时点，得到反射点位置与反射夹角，再利用向后处理过程运用旅行时线性插值算法，从反射点分别到激发点、接收点反向追踪射线路径，最后得到反射波两点射线路径。     

SAR的海洋遥感探测技术综述

从研究SAR的海洋遥感探测重要性和基本特点出发,概述了SAR系统的海洋遥感探测技术所涉及的主要研究内容,针对海洋环境要素分布的随机性和时变性,研究了海面微波散射特性和SAR的海面成像机理,给出了研究结果;分析了SAR系统主要特点,提出研究包括系统的宽测绘带特性和雷达的弱信号获取、海面精确成像算法和时空相关性等方面;同时探讨了海洋目标检测的技术途径,以满足SAR系统海洋观测应用的需要.     

论长波框架中的世界经济走势

在世界经济增长和发展的过程中 ,存在着四种相互包容、相互叠加的经济周期。 2 0世纪 90年代以来 ,世界经济进入了第五个长波上升期 ,其突出表现是新经济带来的快速增长 ,其动力是作为技术创新和制度创新的信息化和经济全球化。在这次长波上升期中 ,世界经济表现出均等化和两极分化两种趋势 ,从而改变着世界经济格局。在长波上升期中 ,如果没有外生的重大随机冲击 ,短周期和主周期一般来说会出现波动相对弱化现象。     

Poliovirus Surveillance by Examining Sewage Water Specimens: Studies on Detection Probability Using Simulation Models

Efficiency of environmental surveillance of poliovirus circulation was studied using simulation models. First, three transmission models were defined for describing different scenarios of poliovirus infections in a large unstructured population. Second, environmental factors, such as the total volume of the sewage network and losses of viruses, were modeled for computing the virus output at the sewage sampling site. Third, the effect of sampling and laboratory procedures was accounted for in the probability of detection, given the amount of polioviruses in a specimen. The simulation model can be used for theoretical assessments of the likely efficiency of environmental surveillance, compared with acute flaccid paralysis (AFP) surveillance. Under reasonable assumptions in a vaccinated population, the AFP surveillance can be outperformed if the poliovirus outbreak is not large. However, this depends on the assumed case-to-infection ratio and on the sampling frequency of the sewage water specimens. Increasing the latter will lead to a higher detection probability, which will further enhance the method based on environmental surveillance.     

正则长波方程的同宿轨道

在对一类正则长波方程定性分析的基础上,得到了其全局相图.由此推知,此类方程具有渐近值相同的钟状孤波解,并求得了其精确孤立波解,即此正则长波方程的同宿轨道.     

Acoustic Cocooning

ABSTRACT

Since the late 1990s, car manufacturers increasingly underline their cars' interior tranquility. Both this acoustic condition and the availability of car audio sets enable drivers to transform their car into a highly personal, controlled and relaxing sonic bubble.

Yet how could the car, once a noisy contraction, evolve into such a space for acoustic cocooning? This article studies the introduction of car radio and interior car sound design in Europe between the 1920s and the 1990s. The car radio's meaning shifted from an artifact that brought companionship to lonely drivers, to an instrument that helped drivers to mentally block out their fellows on the road. At the same time, listening to engine sounds changed from a drivers' skill to a practice drivers had to de-learn. Moreover, car sound construction shifted from reducing noise to creating target sounds for specific consumer groups.

This article employs three forms of cultural analysis to understand these shifts: an “archeology of corporate culturology,” the symbolism of sound, and Gerhard schulze's theory on the experience society. Finally, by analyzing the rise of acoustic cocooning in the car, it aims to contribute to the study of “techno-cocooning”: the use of technology for creating sensory privacy.     

高校校园网P2P流量检测和分类研究

随着P2P技术的发展及网络流量的急剧增加,如何对不同类型的流量进行控制成为各园区网络管理人员要加以解决的问题。文章提出一种基于主机行为的流量检测方法。该方法不对数据包载荷部分的内容进行检测,而是分析主机通信时的连接特征,并根据特征得到流量的分类。     

随钻声波测井数据实时压缩算法

针对随钻测井信号低传输速率特性，结合随钻声波测井时数据量大的实际，研究了波列数据实时在线压缩算法。在分析随钻声波测井信号特征的基础上，建立了基线和波形相结合的分段压缩