The booming growth of the Internet provides us a great deal of information resource. In this paper, we create a text filtering model based on VSM. In this model,Web text mming is an efficient technique,which discovere...The booming growth of the Internet provides us a great deal of information resource. In this paper, we create a text filtering model based on VSM. In this model,Web text mming is an efficient technique,which discoveres valuable and potential knowledge from those unstructured texts. In this paper,we use VSM as the description of Web text and give a feature subset algorithm which is based on the Genetic Algorthm. This algorithm can greatly improve the efficiency of dealing with Web texts and give much better way to classify and cluster the texts. Our experiments show that this method is active well in feature dimension reduction.展开更多
固相亚格子尺度过滤模型是在高精度的网格下,系统地过滤了基于结合颗粒动理学的双流体模型的模拟结果而得到的曳力和固相应力等本构关系的计算模型。今分别采用固相亚格子尺度过滤模型(Filtered Model I)、壁面修正固相亚格子尺度过滤模...固相亚格子尺度过滤模型是在高精度的网格下,系统地过滤了基于结合颗粒动理学的双流体模型的模拟结果而得到的曳力和固相应力等本构关系的计算模型。今分别采用固相亚格子尺度过滤模型(Filtered Model I)、壁面修正固相亚格子尺度过滤模型(Filtered Model II)和改进的固相亚格子尺度过滤模型(Filtered Model III)模拟NETL/PSRI挑战问题中的提升管内的颗粒流动特性,得到了时均气体压力梯度和时均轴向颗粒速度等分布。亚格子尺度模型和均匀流动模型(Huilin-Gidaspow model)的研究结果相比,改进的固相亚格子尺度过滤模型(Filtered Model III)与实验值更接近,尤其是对于高颗粒浓度流动。壁面修正可以提高压力梯度,从时均轴向颗粒速度分布曲线,可以看出在提升管内颗粒流动结构呈现更为明显的环核流动结构;同时,研究了提升管内气体压缩性、壁面修正和计算网格对模拟结果的影响,分析表明气体的可压缩性对提升管内轴向气体压力梯度有影响,在模拟计算时考虑气体的压缩性,可以提高计算精度。展开更多
文摘The booming growth of the Internet provides us a great deal of information resource. In this paper, we create a text filtering model based on VSM. In this model,Web text mming is an efficient technique,which discoveres valuable and potential knowledge from those unstructured texts. In this paper,we use VSM as the description of Web text and give a feature subset algorithm which is based on the Genetic Algorthm. This algorithm can greatly improve the efficiency of dealing with Web texts and give much better way to classify and cluster the texts. Our experiments show that this method is active well in feature dimension reduction.
文摘固相亚格子尺度过滤模型是在高精度的网格下,系统地过滤了基于结合颗粒动理学的双流体模型的模拟结果而得到的曳力和固相应力等本构关系的计算模型。今分别采用固相亚格子尺度过滤模型(Filtered Model I)、壁面修正固相亚格子尺度过滤模型(Filtered Model II)和改进的固相亚格子尺度过滤模型(Filtered Model III)模拟NETL/PSRI挑战问题中的提升管内的颗粒流动特性,得到了时均气体压力梯度和时均轴向颗粒速度等分布。亚格子尺度模型和均匀流动模型(Huilin-Gidaspow model)的研究结果相比,改进的固相亚格子尺度过滤模型(Filtered Model III)与实验值更接近,尤其是对于高颗粒浓度流动。壁面修正可以提高压力梯度,从时均轴向颗粒速度分布曲线,可以看出在提升管内颗粒流动结构呈现更为明显的环核流动结构;同时,研究了提升管内气体压缩性、壁面修正和计算网格对模拟结果的影响,分析表明气体的可压缩性对提升管内轴向气体压力梯度有影响,在模拟计算时考虑气体的压缩性,可以提高计算精度。
