Validation of a vegetated filter strip model (VFSMOD)

Vegetated filter strips (VFS) are designed to reduce sediment load and other pollutants into water bodies. However, adaptation of VFS in the field has been limited owing to lack of data about their efficiency and performance under natural field conditions. A number of models are available that simulate sediment transport and trapping in VFS, but there is a general lack of confidence in VFS models owing to limited validation studies and model limitations that prevent correct application of these models under field conditions. The objective of this study is to test and validate a process‐based model (VFSMOD) that simulates sediment trapping in VFS. This model links three submodels: modified Green–Ampt's infiltration, Quadratic overland flow submodel based on kinematic wave approximation and University of Kentucky sediment filtration model. A total of 20 VFS, 2, 5, 10 and 15 m long and with various vegetation covers, were tested under simulated sediment and runoff conditions. The results of these field experiments were used to validate the VFS model. The model requires 25 input parameters distributed over five input files. All input parameters were either measured or calculated using experimental data. The observed sediment trapping efficiencies varied from 65% in the 2‐m long VFS to 92% in the 10‐m long filters. No increase in sediment removal efficiency was observed at higher VFS length. Application of the VFS model to experimental data was satisfactory under the condition that actual flow widths are used in the model instead of the total filter width. Predicted and observed sediment trapping efficiencies and infiltration volume fitted very well, with a coefficient of determination (R²) of 0·9 and 0·95, respectively. Regression analyses revealed that the slope and intercept of the regression lines between predicted versus observed infiltration volume and trapping efficiency were not significantly different than the line of perfect agreement with a slope of 1·0 and intercept of 0·0. Copyright © 2001 John Wiley & Sons, Ltd.     

船姿分析及其对多波束测量的影响

根据船体操纵性和耐波性理论，结合船姿实验数据，分析了姿态参数的外界受动因素。考虑船姿对多波束测量的影响，结合多波束测量原理，分析了不同姿态对坐标的影响，给出了相应的坐标计算和误差影响数学模型，最后姿态测量误差对测深的影响，结合IHO测深规定，计算出了不同姿态测量的精度指标；分析了姿态测量误差对条带拼接的影响，并提出了相应的解决方法。     

一个嵌入式文件系统CEFS的设计与实现

详细介绍了一个嵌入式文件系统CEFS的设计与实现。该文件系统是基于实时嵌入式操作系统CR-TOSII内核,采用IMFS和FAT位图文件系统格式实现的。CEFS文件系统分为3个实现层次,自底向上分别是：设备驱动程序、高速缓存管理和文件系统核,并向用户提供了基于POSIX的文件系统API接口。它的最大优点就是文件系统的开放式体系结构。