曲线拟合法在工程机械发动机故障诊断中的应用

曲线拟合法在发动机的故障诊断中可以用以判断发动机的故障类型,本文通过计算时域及频域中工程机械发动机工作时的拟合曲线与标准拟合曲线之间的距离,对发动机进行故障类型判断,通过计算,得出计算结果判定的故障类型与设定故障一致的结论。     

异步电动机型式试验数据处理软件设计

本文介绍了异步电动机型式试验数据处理的数学方法和软件设计步骤。     

大直径圆轴残余剪应力的计算

从受扭圆轴M—φ图的相互换算公式出发,利用Nadai公式,推导出大直径受扭圆轴经弹塑性状态后的残余剪应力计算公式,计算简便、准确,在理论上较好地解决了这一问题,并弥补了各种实测法的不足。     

理论计算法在油气管道设计中的应用

本文应用理论计算法,推导出输油(气)管道功能成本方程,并根据工程实际,绘制出了功能成本曲线图。结果表明该方程普遍适用于油气管理,具有一定的实际意义和参考价值。     

有理Bezier曲线的快速逐点生成算法

该文提出了一种有理Bezier曲线的快速逐点生成算法。该算法不但能够用于低次和高次有理Bezier曲线,而且还能用于均匀有理B样条曲线或NURBUS曲线。该算法具有快速的生成速度、高效率以及广泛的应用价值。     

Self‐similarity for accurate compression of point sampled surfaces

Most surfaces, be it from a fine‐art artifact or a mechanical object, are characterized by a strong self‐similarity. This property finds its source in the natural structures of objects but also in the fabrication processes: regularity of the sculpting technique, or machine tool. In this paper, we propose to exploit the self‐similarity of the underlying shapes for compressing point cloud surfaces which can contain millions of points at a very high precision. Our approach locally resamples the point cloud in order to highlight the self‐similarity of the shape, while remaining consistent with the original shape and the scanner precision. It then uses this self‐similarity to create an ad hoc dictionary on which the local neighborhoods will be sparsely represented, thus allowing for a light‐weight representation of the total surface. We demonstrate the validity of our approach on several point clouds from fine‐arts and mechanical objects, as well as a urban scene. In addition, we show that our approach also achieves a filtering of noise whose magnitude is smaller than the scanner precision.     

Real‐Time Modelling of Fibrous Muscle

Relatively recently it has become apparent that providing human kind with a better healthcare requires personalized, predictive and integrative medicine, for which the building of virtual physiological human (VPH) framework accessible via virtual patient avatar is necessary. Real‐time modelling and visual exploration of such a complex avatar is a challenging task. In this paper, we propose a real‐time method for automatic modelling of an arbitrarily large number of muscle fibres in the volume of a muscle represented by its surface mesh. The method is based on an iterative morphing of predefined fibres template into the muscle volume exploiting harmonic scalar field computed on the surface of muscle. Experiments with muscles of thighs and pelvis show that the method produces realistic shapes of fibres. Our sequential VTK‐based C++ implementation is capable of producing 64 fine fibres within a muscle of 10K triangles in less than 170 ms on commodity hardware making the method suitable for VPH purposes as well as for interactive educational medical software.     

Feature‐Preserving Surface Completion Using Four Points

We present a user‐guided, semi‐automatic approach to completing large holes in a mesh. The reconstruction of the missing features in such holes is usually ambiguous. Thus, unsupervised methods may produce unsatisfactory results. To overcome this problem, we let the user indicate constraints by providing merely four points per important feature curve on the mesh. Our algorithm regards this input as an indication of an important broken feature curve. Our completion is formulated as a global energy minimization problem, with user‐defined spatial‐coherence constraints, allows for completion that adheres to the existing features. We demonstrate the method on example problems that are not handled satisfactorily by fully automatic methods.     

分配曲线经验模型在预测和优化中的应用

重力选煤的预测与优化都是利用分配率的计算来实现的。分配曲线经验模型应用于预测和优化的关键是解决模型参数与分选密度间的变换关系。通过实际预测计算，分析了当前广泛应用的几种分配曲线的经验模型在预测应用中误差较大的原因。并针对复合双曲正切模型，提出了一套模型参数变换公式，通过与其它多种经验模型的对比验证，证明复合双曲正切模型可以更为准确的用于重力选的预测和优化。     

基于Gompertz模型的成品钢材产量预测研究

由于成品钢材业在中国制造业内处于上下游的关键联结点，对成品钢材产量进行科学严谨的预测，为企业管理层进行重大决策提供有科学依据的建议和资料，成为中国制造业亟待解决的重要课题之一。文中提出的基于Gompertz曲线，引入季节模型建立的成品钢材产量预测数学方程，具有数据处理简化及计算量小的特点，有较强的科学性和实用性。