低压烧结温度对一步法制备超细晶WC-Co基硬质合金组织及性能的影响

采用等离子球磨技术制得W-C-10Co-0.9VC-0.3Cr_3C_2纳米复合粉体,并利用单向模压成型法将其压制成生坯,再经低压烧结一步法制备成硬质合金。研究表明,等离子球磨3h所获得的复合粉体呈片层状形貌,并且成分分布均匀。在1 380℃及1 400℃烧结时,由于等离子球磨的特殊作用,VC、Cr_3C_2对WC晶粒长大抑制作用突显。1 380℃烧结制备的硬质合金,致密度为99.2%,WC平均晶粒尺寸为250nm,硬度和横向断裂强度分别为92.3HRA和2 443 MPa,具有最佳的WC晶粒尺寸与致密度配合,以及最佳的综合力学性能。     

Terahertz spectroscopic uncertainty analysis for explosive mixture components determination using multi-objective micro-genetic algorithm

In practical applications, many suspicious samples may be a kind of mixture and consist of various chemical components that make the spectral analysis difficult. Various explosives and related compounds (ERC) in the mixture can be identified and the concentration of each component can be estimated based on the known spectral data of the pure explosive components. In this paper, the terahertz spectroscopic uncertainty analysis using a micro-GA has been proposed, in which the random assignment of alleles from parents to offspring is implied. An intelligent computation-based technical road-map is also provided for the analysis and optimisation of the terahertz spectroscopic combination analysis. A simulation with two given test cases for the ERC has been devised. The results of the simulation show that micro-GA and its derivatives have the potential applications in the fields of security, medicine and food industry to fast identify mixtures.     

Automatic Cage Building with Quadric Error Metrics

Modern computer graphics applications usually require high resolution object models for realistic rendering.However,it is expensive and difficult to deform such models in real time.In order to reduce the computational cost during deformations,a dense model is often manipulated through a simplified structure,called cage,which envelops the model.However,cages are usually built interactively by users,which is tedious and time-consuming.In this paper,we introduce a novel method that can build cages automatically for both 2D polygons and 3D triangular meshes.The method consists of two steps:1) simplifying the input model with quadric error metrics and quadratic programming to build a coarse cage;2) removing the self-intersections of the coarse cage with Delaunay partitions.With this new method,a user can build a cage to envelop an input model either entirely or partially with the approximate vertex number the user specifies.Experimental results show that,compared to other cage building methods with the same number of vertex,cages built by our method are more similar to the input models.Thus,the dense models can be manipulated with higher accuracy through our cages.     

Optimal motion cueing for 5-DOF motion simulations via a 3-DOF motion simulator

This study presents a novel motion-cueing strategy, which is applied to a motion simulator with three rotational degrees of freedom (DOF) to perform the roll, pitch, yaw, surge, and sway motions by using an online optimization algorithm. The weighting functions are adaptively tuned in each step, and the optimal Euler angles are obtained analytically. This motion-cueing algorithm is efficient since it requires no recursive search on the optimal solution. Experiments demonstrating the validity of the 5-DOF motion simulation are also included.     

基于二部图匹配的车载网络分布式存储机制

现有的车载网络中对数据存储机制的研究大多以移动车载节点作为数据载体,然而车载节点的快速移动、存储空间有限、存在安全风险等特性,限制了车载网络数据存储性能的进一步优化.针对部署有路边基础设施的车载网络场景,以路边单元作为存储节点,提出了基于二部图匹配的车载网络分布式存储机制（distributed storage scheme,简称DSS）.在车载网络中,以最大化数据响应率为目标,路边单元的数据存储问题是NP完全问题.首先,依据请求分割规则将原问题转化为二部图最大匹配问题,其中,二部图左顶点代表车载节点的请求,右顶点代表路边单元的存储单元;进而,利用Hungarian算法在多项式时间内求得最优解.由于问题转化可能造成不同路边单元存储相同数据的冗余问题,设计了冗余副本清理算法,依据不同副本的响应因子排序,检查并清理冗余副本.实验结果表明：DSS能够提高数据响应率,降低响应时延,并保持较小的网络资源开销.     

多标签快速识别算法研究与改进

为了提高Aloha算法中标签的识别效率,根据ISO/IEC18000-6C国际标准中的防碰撞要求,对时隙计数(Q)的选择进行动态调整,以满足标签快速识别的要求,实现了一种动态的时隙Aloha算法。除此以外,在此基础上提出了对标签数量进行分组,分析了满足最大时隙利用率的客观条件,对动态时隙Aloha算法进行改进。仿真结果显示,改进后的算法提高了标签的识别效率,表现出良好的性能,具有一定的研究价值。     

Enhancing pose accuracy of space robot by improved differential evolution

Due to the intense vibration during launching and rigorous orbital temperature environment, the kinematic parameters of space robot may be largely deviated from their nominal parameters. The disparity will cause the real pose (including position and orientation) of the end effector not to match the desired one, and further hinder the space robot from performing the scheduled mission. To improve pose accuracy of space robot, a new self-calibration method using the distance measurement provided by a laser-ranger fixed on the end-effector is proposed. A distance-measurement model of the space robot is built according to the distance from the starting point of the laser beam to the intersection point at the declining plane. Based on the model, the cost function about the pose error is derived. The kinematic calibration is transferred to a non-linear system optimization problem, which is solved by the improved differential evolution (DE) algorithm. A six-degree of freedom (6-DOF) robot is used as a practical simulation example, and the simulation results show: 1) A significant improvement of pose accuracy of space robot can be obtained by distance measurement only; 2) Search efficiency is increased by improved DE; 3) More calibration configurations may make calibration results better.     

基于动态领域模型的页面设计模式

当系统中页面很多时,针对每个页面分别设计实现的方法开发成本太高,且难以维护.为了解决这个问题,提出了动态页面设计模式.这种模式使用动态领域建模的方法,特页面上的控件抽象成领域元素,控件的特性抽象成元素的属性,然后在领域模型的基础上建立一个页面设计平台.使用该平台可以在不修改源代码的基础上,可以动态地新增或修改页面,对于有特殊要求的页面,使用服务,插件等方法进行实现.这种方法具有很高的理论和应用价值.     

基于完成端口的消防通信服务器设计和实现

为满足消防灭火救援接处警系统中对通信服务器的性能和稳定性要求,在完成端口的基础上设计了分层结构的通信服务器架构。本文给出了该服务器架构的框架组成,并说明如何利用了完成端口框架实现通信处理并给出实现程序代码。最后给出了该架构在实现接处警系统中订阅发布业务中的具体应用。     

两输入幂激励前向神经网络权值与结构确定

基于多元函数逼近与二元幂级数展开理论,构建了一个以二元幂函数序列为隐神经元激励函数的两输入幂激励前向神经网络模型.以该网络模型为基础,基于权值直接确定法以及隐神经元数目与逼近误差的关系,提出了一种网络权值与结构确定算法.计算机仿真与数值实验结果验证了所构建的网络在逼近与去噪方面具有优越的性能,所提出的权值与结构确定算法能够快速、有效地确定网络的权值与最优结构,保证网络的最佳逼近能力.