基于计算机网络的下一代软件无线电

1.引言软件无线电(Software Radio,Software Defined Radio)起源于美国国防部的易通话(speakeasy)战术通信系统计划。软件无线电的概念是在1992年全美远程会议上由Joe Mitola等人率先提出的,其定义为:软件无线电基于一个硬件平台,其A/D(模/数)变换应尽量靠近天线,而将尽可能多的无线通信用软件来实现。由此可见,软件无线电代表的是一个软件可重构的无线电体系,它的可重构性主要体现在其射频(RF)、中     

Interactive Construction and Animation of Layered Elastically Deformable Characters

An interactive system is described for creating and animating deformable 3D characters. By using a hybrid layered model of kinematic and physics-based components together with an immersive 3D direct manipulation interface, it is possible to quickly construct characters that deform naturally when animated and whose behavior can be controlled interactively using intuitive parameters. In this layered construction technique, called the elastic surface layer model, a simulated elastically deformable skin surface is wrapped around a kinematic articulated figure. Unlike previous layered models, the skin is free to slide along the underlying surface layers constrained by geometric constraints which push the surface out and spring forces which pull the surface in to the underlying layers. By tuning the parameters of the physics-based model, a variety of surface shapes and behaviors can be obtained such as more realistic-looking skin deformation at the joints, skin sliding over muscles, and dynamic effects such as squash-and-stretch and follow-through. Since the elastic model derives all of its input forces from the underlying articulated figure, the animator may specify all of the physical properties of the character once, during the initial character design process, after which a complete animation sequence can be created using a traditional skeleton animation technique. Character construction and animation are done using a 3D user interface based on two-handed manipulation registered with head-tracked stereo viewing. In our configuration, a six degree-of-freedom head-tracker and CrystalEyes shutter glasses are used to display stereo images on a workstation monitor that dynamically follow the user head motion. 3D virtual objects can be made to appear at a fixed location in physical space which the user may view from different angles by moving his head. To construct 3D animated characters, the user interacts with the simulated environment using both hands simultaneously: the left hand, controlling a Spaceball, is used for 3D navigation and object movement, while the right hand, holding a 3D mouse, is used to manipulate through a virtual tool metaphor the objects appearing in front of the screen. Hand-eye coordination is made possible by registering virtual space to physical space, allowing a variety of complex 3D tasks necessary for constructing 3D animated characters to be performed more easily and more rapidly than is possible using traditional interactive techniques.     

Fe_2O_3基陶瓷的气湿敏特性

论述了由不同制备工艺获得的Ｆｅ２Ｏ３陶瓷及各种添加剂下表面羟基和吸附氧的形成和性质，分析了表面羟基和吸附氧的酸碱性对气湿特性的影响。     

三维折射率场干涉图像的处理方法

基于最小误差阈值理论，采用实平面上的低通滤波技术，对三维折射率场干涉图上的噪音进行了处理，提出了一种与普通细化算法不同的并行细化算法，并对剔除分枝的具体方法作了介绍，通过实例说明了条纹剔除的过程。     

YQ—3000测量机控制系统

本文较系统、全面地介绍了我国自行设计研制的第一台大型CNC三座标测量机自动控制及数据处理系统．该机控制系统的成功研制，对于三座标测量机、测量（工业）机器人和数控加工设备等领域具有进一步推广、开发应用的普遍现实指导意义．     

非正弦不对称三相三线电路负载侧相电压的定义与测量

对非正弦不对称三相三线电路，如何恰当地定义负载侧的相电压并能方便地测量一直未有明确的统一认识。本文从研究三相三线电路中相电压与线电压的关系着手，根据外部等效的思想。来定义三相三线电路负载侧的相电压。按此定义的相电压恒满足ｕ，＋“ｂ＋“ｃ＝０，并可方便地通过三相电压互感器或直接依据负载侧的线电压来唯一确定负载侧的相电压。     

新试剂2-(2''''-苯并噻唑偶氮)-1,8-二羟基-3,6-萘二磺酸与钛(Ⅳ)和 CTMAB 形成三元络合物显色反应的研究

在阳离子表面活性剂ＣＴＭＡＢ存在下，２－（２′－苯并噻唑偶氮）－１，８－二羟基－３，６－苯二磺酸与钛（Ⅳ）在ｐＨ３．５～４．５范围内发生高灵敏的显色反应，形成一种蓝色的三元胶束络合物，其最大吸收波长位于６５０ｎｍ，表观摩尔吸光系数ε＝１．２２×１０５·Ｌ·ｃｍ－１。络合物中钛（Ⅳ）与显色剂的组成比为１：２，钛含量在０～８．０μｇ／２５ｍＬ范围内符从比尔定律。间用于铝合金中微量钛的测定，结果满意。     

EFFECTS OF In_2O_3 DOPING AND SINTERING TEMPERATURE ON THE ELECTRICAL PROPERTIES OF ZnO VARISTORS

ZnOvaristorshaveexcellentnon--linearcurrent--voltage(IV)characteristicsandenergyabsorptionability,makingthemvaluableasvoltagesuppressersinpowersystemsandelectroniccircuitsLlj.Thecurrentvoltagedependenceofvaristorsisdescribedbytherelation:I=C(V)"whereIisthecurrentdensity,Caconstant,Vthevoltage,andathecoefficientofnon--linearity.ThestudyresultsshowthatpureZnOgrainhasnottheelectricalconductivity.Intheprocessofitspreparation,thedefectisproducedinthegrain,andmakeitann--typesemiconductor.Thecer…     

Numerical inversion of multidimensional Laplace transforms by the Laguerre method

Numerical transform inversion can be useful to solve stochastic models arising in the performance evaluation of telecommunications and computer systems. We contribute to this technique in this paper by extending our recently developed variant of the Laguerre method for numerically inverting Laplace transforms to multidimensional Laplace transforms. An important application of multidimensional inversion is to calculate time-dependent performance measures of stochastic systems. Key features of our new algorithm are: (1) an efficient FFT-based extension of our previously developed variant of the Fourierseries method to calculate the coefficients of the multidimensional Laguerre generating function, and (2) systematic methods for scaling to accelerate convergence of infinite series, using Wynn's ε-algorithm and exploiting geometric decay rates of Laguerre coefficients. These features greatly speed up the algorithm while controlling errors. We illustrate the effectiveness of our algorithm through numerical examples. For many problems, hundreds of function evaluations can be computed in just a few seconds.     

Application of multi-layer perceptron neural networks to vision problems

This paper discusses the application of a class of feed-forward Artificial Neural Networks (ANNs) known as Multi-Layer Perceptrons(MLPs) to two vision problems: recognition and pose estimation of 3D objects from a single 2D perspective view; and handwritten digit recognition. In both cases, a multi-MLP classification scheme is developed that combines the decisions of several classifiers. These classifiers operate on the same feature set for the 3D recognition problem whereas different feature types are used for the handwritten digit recognition. The backpropagationlearning rule is used to train the MLPs. Application of the MLP architecture to other vision problems is also briefly discussed.