DTCWT-based zinc fast roughing working condition identification

The surface texture of mineral flotation froth is well acknowledged as an important index of the flotation process.The surface texture feature closely relates to the flotation working conditions and hence can be used as a visual indicator for the zinc fast roughing working condition. A novel working condition identification method based on the dual-tree complex wavelet transform(DTCWT) is proposed for process monitoring of zinc fast roughing.Three-level DTCWT is implemented to decompose the froth image into different directions and resolutions in advance, and then the energy parameter of each sub-image is extracted as the froth texture feature. Then, an improved random forest integrated classification(i RFIC) with 10-fold cross-validation model is introduced as the classifier to identify the roughing working condition, which effectively improves the shortcomings of the single model and overcomes the characteristic redundancy but achieves higher generalization performance. Extensive experiments have verified the effectiveness of the proposed method.

Using Successive Multi-Goals Method in the Individual-Based Model to Simulate Crowd Behavior during Evacuation Processes

The fact of proportional population growth in many countries drags the attention of researchers in the field of crowd dynamics to the need for developing reliable models to predict the behavior of human crowds in emergency situations such as evacuation processes. Computer based models that simulate human crowd dynamics prove to offer the optimum way to predict the crowd realistic behavior especially in emergency situations. This paper presents a vital extension of my previous work in which an individual-based model to simulate the behavior of human crowd was developed using the artificial potential fields to describe the interaction forces between each crowd member and the environment on one side and amongst the crowd members on the other side to add realistic flavor to the predicted crowd behavior. In this paper, the successive multi-goals （SMG） method, which is a new method to represent the environment in which the crowd moves, is developed. Rather than using the traditional static potential field, the successive multi-goals method uses a dynamic potential field which is vital to solve the reactive problem that is considered as a drawback of the model when simulating the human crowd behavior during evacuation of buildings whose structures are complex such as bottlenecks and narrow corridors. Numerical results that match the real behavior of human individuals in emergency situations prove the efficiency of the new method to solve the problem on an individual basis as well as its applicability.

基于应变测量的结构载荷分布反演方法

针对基于应变测量的载荷分布反演,首先对比分析现有几种影响系数法,并讨论影响载荷反演精度的几个关键问题。为解决单位载荷工况选取的难题,提出一种基于施密特正交化的最大垂直距离逐步筛选基工况法,从设计载荷工况库中筛选载荷基工况和应变基工况,建立一套完整的工程可行的载荷分布反演流程。为解决反向矩阵病态化的难题,引入Tikhonov正则化方法。以某型飞机机翼疲劳试验作动筒载荷和光纤传感器数据为算例,假设3种应变测量误差情况(无误差、5%随机误差、10%随机误差),验证了提出的载荷分布反演方法具有很高的预测精度和鲁棒性,可为新一代航空航天器的结构健康监控提供一条可靠的载荷识别途径。