多障碍物环境下机器人的连续避障策略

本文针对多障碍物环境下,机器人避障过程中又出现障碍物这一情况,设计了一种避障策略,来实现机器人的连续避障并到达指定目标点的功能。在该策略中,设计了一套基于避障状态的方向选择规则,并提出了一种象限法,来决定机器人的当前行为。实验证明,该策略实现简单,并可较大限度地降低避障行为的盲目性和重复性。     

Neural Network Based Feedback Linearization Control of an Unmanned Aerial Vehicle

This paper presents a flight control design for an unmanned aerial vehicle (UAV) using a nonlinear autoregressive moving average (NARMA-L2) neural network based feedback linearization and output redefinition technique.The UAV investigated is non- minimum phase.The output redefinition technique is used in such a way that the resulting system to be inverted is a minimum phase system.The NARMA-L2 neural network is trained off-line for forward dynamics of the UAV model with redefined output and is then inverted to force the real output to approximately track a command input.Simulation results show that the proposed approaches have good performance.     

基于覆盖算法的煤炭供应商评测模型

阐述了当前进行煤炭供应商评测的方法以及这些方法的弊端。针对这种弊端,根据煤炭供应商评测的特点,利用前向神经网络的交叉覆盖算法及其改进算法对煤炭供应商供货质量进行了评测,在实验中将其与统计理论中加权平均的方法进行比较,证明取得了不错的效果,同时证明了核覆盖算法对交叉覆盖算法的改进。     

一类小型软件企业实施CMM2级的研究

分析了基于SSR需求的测试项目的特点和以该类项目为主的小型软件企业的特点，并通过实例阐述了这类组织实施CMM2级的一些要点和实施过程中要注意的问题。根据对项目和组织的特点分析及对实施CMM2级后组织的能力成熟度的提升和软件过程改进后的效果的分析，得出实施CMM2级能够使以基于SSR需求的测试项目为主的小型软件企业实现有效的软件过程改进。     

基于实例的汉蒙机器翻译

本文通过对汉蒙机器翻译方法的研究,给出了一种基于实例的汉蒙机器翻译方法,并加以了实现。本文给出了用于汉蒙EBMT机器翻译的实例搜索以及短语片段划分、匹配、组合的方法。本文给出的方法是基于词语对齐的,利用词语对齐进行词语的匹配,并根据匹配词数和长度计算相似度,选取最好的实例。通过对齐信息,确定片段组合的策略,生成翻译结果。通过对方法的实现和实验,完成了一个基于实例的汉蒙机器翻译系统。     

基于物理模型的交互式服装实时动画

提出了一种用于实现基于物理模型的交互式服装实时动画的方法。由于基于物理的服装模型本身与碰撞检测涉及大量的计算,因此随人体运动的交互式服装实时动画一直是一个具有挑战性的课题。为了提高模拟性能,首先简化经典的“质点-弹簧”模型,并利用“半刚性-复杂摆”模型经向与纬向约束分开计算的优点;其次,在服装与人体之间的碰撞检测采用椭圆包围盒的检测方法,并根据碰撞检测本身存在的局部性,通过时间与空间相关性来加速。实验结果证明,本文方法与传统的方法相比,大量减少了计算,完全可以实现随人体运动的交互式服装实时动画。     

Correlation-based tuning of decoupling multivariable controllers

The iterative method labelled correlation-based tuning (CbT) is considered in this paper for tuning linear time-invariant multivariable controllers. The approach allows one to tune some elements of the controller transfer function matrix to satisfy the desired closed-loop performance, while the other elements are tuned to mutually decouple the closed-loop outputs. Decoupling is achieved by decorrelating a given reference with the non-corresponding outputs. The controller parameters are calculated either by solving a correlation equation (decorrelation procedure) or by minimizing a cross-correlation function (correlation reduction). In addition, the preferred way of exciting a 2×2 system for CbT is investigated via the accuracy of the estimated controller parameters. It is shown that simultaneous excitation of both reference signals does not improve the accuracy of the estimated controller parameters compared to the case of sequential excitation. In fact, one must choose between low experimental cost (simultaneous excitation) and better accuracy of the estimated parameters (sequential excitation). The theoretical results are illustrated via three simulation studies.     

Improvement on the Oxidation Resistance of a Ti3Al Based Alloy by Cr1-xAlxN （0≤x≤0.47） Coatings

Cr1-xAlxN coatings have been deposited on a Ti3Al based alloy by reactive sputtering method. The results of the isothermal oxidation test at 800-900℃ showed that Cr1-xAlxN coatings could remarkably reduce the oxidation rate of the alloy owing to the formation of Al2O3＋Cr2O3 mixture oxide scale on the surface of the coatings. No spallation of the coatings or oxide scales took place during the cyclic oxidation at 800℃. Ti was observed to diffuse into the coatings, the diffusion distance of which was very short, and the diffusion ability of it was proportional to the AI content in the coatings. Compared to Ti, Nb can diffuse much more easily through the whole coatings and oxide scales.     

淀粉与乙酸乙烯酯-丙烯酸乙酯的合成与应用研究

以玉米淀粉为接枝骨架,过硫酸铵为引发剂,丙烯酸乙酯(EA)和乙酸乙烯酯(VAc)为接枝单体,进行接枝共聚,制备淀粉基木材胶粘剂.研究了反应时间、反应温度、引发剂用量以及两单体配比对淀粉与丙烯酸乙酯-乙酸乙烯酯接枝共聚反应的影响.结果表明,当引发荆浓度9.7×10-3mol/L、反应温度65℃、反应时间3h、VAc和EA体积比为6:4时,可得到较高的接枝效率和接枝率.