Design and Fabrication of a Bio-inspired Acceleration Sensor Using Liquid Mass Blocks

A linear acceleration sensor,which is inspired by the human balance organ,is designed and prepared. It uses a liquid mass-block and a symmetrical-electrodes metal-core polyvinylidene fluoride fiber(SMPF)as the sensor element. The output signal of the sensor has an exponential relationship with the excitation amplitude of the impacting vibration. It is capable of detecting the amplitude and the correct frequency for sinusoidal excitations using an exponential correlation. The experiments indicate that both the output signal of the sensor and the resonance frequency increase substantially with increasing diameter of the metal core. The first-order resonance frequencies of the sensors with 40,60,and 80 μm diameter metal wires are below 10 Hz,which is near the range of human body motion frequencies.     

众眼看宇宙

这张照片的主角是我们太阳系最奇特的卫星——木卫一的真彩色照片。原图由1995年～2003年之间环绕木星的"伽利略"号探测器拍摄,经过复杂技术的处理,才还原给我们一个真实的木卫一。木卫一的主色调来自硫酸和硅酸盐岩浆。它的表面有许多活火山,在木星和其他木星卫星的强大引力作用     

类X-38升力体运载器气动布局概念设计

开展升力体运载器的气动布局概念设计研究,利用二次曲线横截面及模线设计方法,提出一种类X-38升力体运载器气动外形,进行机体的优化和控制舵的匹配设计,研究飞行器的气动特性和操纵效率问题。研究表明,该方案可以获得较高的配平升阻比及配平攻角,有较高的容积效率和机动控制效率,可以作为未来航天运载器的潜在可行方案。     

一种基于先验知识的3D位姿参数识别方法

计算机视觉中用单幅照片来识别三维物体的六个自由度是非常困难的，但是，在知道一些先验知识的情况下，可以对物体的六个自由度进行识别。本文提出一种基于先验知识的三维位举参数识别的方法，使用物体上不共线的三个特征点及目标点来确定物体的位置和姿态，给出了六个参数的解析表达式，在实时处理中可以得到好的效果。     

Periodic ambiguity functions of EQC-based TFHC

The time-frequency hop codes based upon extended quadratic congruences (TFHC-EQC) were developed previously (1988, 1991). The known results about the ambiguity functions of the TFHC-EQC are extended from aperiodic cases to periodic cases. Precisely, the following new results are proved: (1) The tight upper bound for the periodic auto-ambiguity function of the TFHC-EQC is 6; (2) the periodic cross-ambiguity upper bound of the TFHC-EQC is at least (N-1)/2; (3) there exists a subset TFHC-EQC of volume (N-1)/2 such that its periodic cross-ambiguity is tightly upper bounded by 8     

机上无线局域网用户行为分析

随着无线网络的普及,用户的上网行为分析已经成为各单位提高服务质量、增长收益的重要途径。概述了Web日志挖掘的相关概念、方法和步骤。针对机上无线局域网的用户访问行为,对用户访问日志进行预处理,由日志中的旅客座位信息所关联到的旅客基本信息来确定旅客类别,通过计算分析用户的访问兴趣度,最终得出不同类别旅客的访问兴趣分布。     

Fault rupture model of the 2008 Dangxiong (Tibet,China) Mw 6.3 earthquake from Envisat and ALOS data

On October 6, 2008, an Mw 6.3 earthquake occurred in Dangxiong county, southern Tibetan Plateau. In this study, Synthetic Aperture Radar (SAR) images from Envisat ASAR C-band descending Track 176 and ALOS PALSAR L-band ascending Track 500 are processed to generate the coseismic deformation caused by the earthquake. To estimate the source model, a downhill simplex non-linear inversion method is used to determine the fault rupture geometry, and an automatic fault discretization technique is employed to divide the fault plane to construct the optimal slip model, in which the uncertainties of the fault parameters are assessed by a Monte Carlo method. The inversion results show that the earthquake strikes almost south–north and has a normal faulting focal mechanism with rake angle and slip of −111.7° and 1.33 m, respectively. Peak slip of 2.15 m is located at a depth of 7.5 km. The estimated geodetic moment is 4.06 × 10¹⁸ N m (Mw 6.37), 71.2% of which is released in the depth range 4.5–11 km. The slip model suggests that coseismic slip also takes place at some fault patches near the earth’s surface and postseismic afterslip occurs below the coseismic rupture area after the earthquake.     

基于时间序列的机票价格预测模型

随着航空业的发展以及人们生活水平的提高,越来越多的人选择飞机作为自己的出行方式,但航空公司根据收益管理系统进行实时价格调整,票价变化明显.票价浮动大这一特点使价格预测极具实际应用价值.提出运用时间序列算法进行建模,设计并实现了基于时间序列的机票预测算法,通过比较分析预测结果与实际旅游网站发布价格,表明该模型可为旅客提供较可靠的购票决策支持,并为旅客节省开支.     

大尺寸测量系统配置中包络性与可达性分析

构建了包络性和可达性分析的原理与公式，定量判定当前测量设备空间位置是否合理，为实现在大尺寸测量方案规划阶段对测量设备的可行空间进行快速有效的规划提供依据。阐述了大尺寸测量系统总体架构与阶段任务划分，定义了包络性与可达性的输入输出关系。论述了包络性与可达性的原理与公式，包括可测量体素和外包络体的定义、数学模型和推导公式以及判定公式。最后，在CATIA环境下开发包络性和可达性分析工具，并以机翼翼肋为例，对该翼肋上待测关键特征进行包络性和可达性仿真分析。仿真结果表明，该包络性与可达性分析的原理与公式是可行的。     

力值加载校准系统误差补偿方法研究

针对飞机液压系统地面测试设备校准方法和校准装置欠缺的问题,为了提高飞机液压系统地面测试设备的测试性能和可靠性,设计了一套力值加载校准系统,该校准系统能够按着设置的参数输出精确的力值,实现对飞机液压系统地面测试设备的校准.满足了飞机液压系统地面测试设备对校准方法和校准装置的需求.