树木生长中树枝形态的3D建模

3D造型的基本目标就是在可接受的算法复杂性下，生成真实感可以与实物媲美的虚拟物体。静态的树的3D造型方法通常利用树的分形特征和随机性。我们运用动态的基于生长的树的造型方法。树形态的形成受内在基因和外在环境因素影响，因此可以通过控制树的生长过程实现其造型。在系统中引入了力的概念，用来控制树的生长．有两种类型的力，称为内力和外力，分别模拟树自身的生命力和外界的环境因素．结合分形机制，该系统可以模拟各种常规状态的树。该动态系统的突出特点是可以方便地控制最终造型，通过调整力参数，可以获得最终造型的连续变化和形态控制。     

Quality/value relationships for imperfect weather forecasts in a prototype multistage decision-making model

Some theoretical results concerning the nature of the relationship between the scientific quality and economic value of imperfect weather forecasts are obtained. A prototype multistage decision-making model is considered, involving only two possible actions and two possible states of weather. This particular form of model is motivated by a real-world application known as the fruit-frost problem. For an infinite-horizon, discounted version of this model it is shown that economic value remains zero below a forecast quality threshold and then rises monotonically but nonlinearly above this threshold. In particular, the relative sensitivity of economic value to changes in the quality of forecasts increases as perfect information is approached. This curve is compared with quality/value relationships that have been obtained for other versions of the model; namely, a single-stage model and a multistage, finite-horizon model.     

键合图法非线性系统动态仿真

线性系统动态仿真的键合图法已经较完善地建立起来。但是对非线性系统应用键合图法进行动态仿真尚有许多工作要做,这不仅由于其系统状态方程的建立比较复杂,而且其解法也比较复杂。本文在考虑到混合因果关系的情况下,推出了非线性多流口系统状态方程的统一表达式,并采用有限差分同Broyden的拟牛顿法相结合来求解。最后,给出具体实例对所述方法加以验证。     

On Incentive Equlibria for Dynamic Games

ＯｎＩｎｃｅｎｔｉｖｅＥｑｕｌｉｂｒｉａｆｏｒＤｙｎａｍｉｃＧａｍｅｓ￥ＺＨＵＳｈｉｊｉｎｇ；ＷＡＮＧＸｉａｎｊｉａ；ＣＨＥＮＴｉｎｇ（ＩｎｓｔｉｔｕｔｅｏｆＳｙｓｔｅｍｓＥｎｇｉｎｅｅｒｉｎｇ，ＨｕａｚｈｏｎｇＵｎｉｖｅｒｓｉｔｙｏｆＳｃｉｅｎｃｅ...     

ARMAX模型在飞机火控系统精度试验中的应用

火控系统精度试验包括检验火控系统的静态精度和动态精度。动态精度试验是指在火控系统静态试验满足精度指标后 ,在目标和飞机处于相对运动的状态下 ,检查火控系统输出值相对标准值的误差。采用ARMAX模型进行火控系统动态精度的简易测试 ,动态建模后经过残差检验、零极点分析等 ,为精度试验分析提供了一种简单方法     

基于DWT和DFT的动平衡机不平衡量提取原理及实现

在超微型转子(质量小于10g)动平衡机中,主要干扰分为同频干扰、高频干扰和低频干扰。针对测试环境中不平衡量信号的特点,利用离散小波变换对信号进行3层分解,提取有用的低频信号、接着进行频谱分析,在频域提取不平衡量所对应的幅度和相位,有效地滤除了信号中混杂的低频及高频干扰,所测得的误差大大减小,不平衡量幅度测试精度达4μm,相角小于2°,为保证平衡机系统一次去重90％以上提供了前提。所用算法在数字信号处理器上实现。     

Dynamic Logic in Control

Ｄｙｎａｍｉｃ　Ｌｏｇｉｃ　ｉｎ　ＣｏｎｔｒｏｌＨｅＷｅｉｄｏｎｇ，ＹｕＸｉｎｙａｏ，ＣｈｅｎＺｈｏｎｇｊｉ＆ＺｈａｎｇＭｉｎｇｌｉａｎ（Ｄｅｐｔ．ｏｆＡｕｔｏｍａｔｉｃＣｏｎｔｒｏｌｏｆＢｅｉｊｉｎｇＵｎｉ．ｏｆＡｅｒｏ．＆Ａｓｔｒｏ．，Ｂｅｉｊｉ...     

动力学系统中连续白噪声的数字仿真

在对有连续高斯白噪声作输入的线性连续动力学系统作数字仿真时，必须慎重选择随机数发生器的统计性质，以使系统得到“忠实”的反映。本文给出了随机数产生器的统计性质和连续随机过程的统计性质之间的关系，指出前者不仅依赖于后者及系统本身，还依赖于数字仿真中所采用的积分方法和积分步长。最后，以Ｅｕｌｅｒ积分和Ｒｕｎｇｅ－ｋｕｔｔａ积分为例，分别给出了相应的公式。     

Dynamic Optimization Algorithm for Flying Trajectory of a Free-flying Space Robot

A new method of dynamic optimization for the flying trajectory of a free-flying space robot based on its flying motion characteristics is presented. The continuous flying trajectory is broken into a number of segment and the control efforts and the duration of the segment are chosen as the optimization parameters. The objective function is made by using the weighted sum of the fuel used and the time spent, and the constraint equations are selected. Finally, the internal point punishment function method is adopted in the optimization program, and the results of computer simulation are given.