智能滴灌施肥控制系统中 pH调节品质的优化     

陈希  芦亚丽 《农业网络信息》2004,(10):12-14

利用遗传神经网络,通过对其权值的训练,优化权系数和网络结构.由可测的输出变量,将诸多有关作物 pH值调节的扰动推算出来,实现最优控制.仿真结果表明它能使加酸施肥系统控制偏差不超过± 2%,优化了调节品质.  相似文献   

Incorporating connectivity into reserve selection procedures   总被引：1，自引：0，他引：1  

Robert A. Briers 《Biological conservation》2002,103(1):77-83

Methods for selecting sites to be included in reserve networks generally neglect the spatial location of sites, often resulting in highly fragmented networks. This restricts the possibility of dispersal between sites, which for many species may be essential for long-term persistence. Here I describe iterative reserve selection algorithms which incorporate considerations of reserve connectivity and evaluate their performance using a data set for macroinvertebrates in ponds. Methods where spatial criteria were only invoked when ties between sites occurred did not perform significantly better than a simple greedy algorithm in terms of reserve connectivity. An algorithm based on a composite measure of species added and changes in reserve connectivity produced a reserve network with higher connectivity, but needed more sites to represent all species. A trade-off between connectivity and efficiency may be inevitable, but the costs in terms of efficiency may be justified if long-term persistence of species is more likely.  相似文献   

汽车多路传输系统数据的简化算法     

刘春辉  李翔晟 《中南林学院学报》2006,26(2):106-111

介绍了一种应用于汽车多路传输系统中所有关联数据库数据的简化算法．同时对此算法进行了具体的性能分析．汽车多路传输系统允许汽车电子系统内各个智能模块共享信息。实现了信息在各个电子模块中进行实时交换，从而能提高各个智能模块之间的信息交换速度．  相似文献   

基于证书认证机制的公平文件交换协议的算法设计     

李平 《湖南农业大学学报(自然科学版)》2004,31(1)

在电子商务活动中，进行实时公平的文件交换具有非常重要的意义．本文利用证书认证机制中简单、快速且交换活动脱离等特点，结合RSA算法构造出具备实时公平交换功能的文件交换协议．同时根据测试数据对该协议的各项性能与其它类似协议进行了简要分析．最后提出了可行的协议假定的实现流程．  相似文献   

稀疏生成矩阵的低编码复杂度非正规LDPC码性能     

唐蕾  仰枫帆 《勤云标准版测试》2006,(3):202-207

提出了一种新的基于稀疏生成矩阵的高性能非正规LDPC码的构造方法，并研究了其性能。与传统的由校验矩阵定义的LDPC码相比，在相同的译码复杂度前提下，非正规LDPC码的编码复杂度更低。模拟结果显示，在加性高斯白噪声信道下，非正规LDPC码的性能要显著优于传统LDPC码。  相似文献   

一种改进的单纯形算法实现及其应用     

王东雷  张耀中 《安徽农业科学》2007,35(35):11601-11602

针对资源最优配置问题,在对单纯形算法描述的基础上,提出了一种改进的单纯形算法,介绍了其实现方法,并用实例验证了其有效性。  相似文献   

Estimation of soil organic matter in the Ogan-Kuqa River Oasis,Northwest China,based on visible and near-infrared spectroscopy and machine learning     

ZHOU Qian 《干旱区科学》2023,15(2):191-204

Visible and near-infrared (vis-NIR) spectroscopy technique allows for fast and efficient determination of soil organic matter (SOM). However, a prior requirement for the vis-NIR spectroscopy technique to predict SOM is the effective removal of redundant information. Therefore, this study aims to select three wavelength selection strategies for obtaining the spectral response characteristics of SOM. The SOM content and spectral information of 110 soil samples from the Ogan-Kuqa River Oasis were measured under laboratory conditions in July 2017. Pearson correlation analysis was introduced to preselect spectral wavelengths from the preprocessed spectra that passed the 0.01 level significance test. The successive projection algorithm (SPA), competitive adaptive reweighted sampling (CARS), and Boruta algorithm were used to detect the optimal variables from the preselected wavelengths. Finally, partial least squares regression (PLSR) and random forest (RF) models combined with the optimal wavelengths were applied to develop a quantitative estimation model of the SOM content. The results demonstrate that the optimal variables selected were mainly located near the range of spectral absorption features (i.e., 1400.0, 1900.0, and 2200.0 nm), and the CARS and Boruta algorithm also selected a few visible wavelengths located in the range of 480.0-510.0 nm. Both models can achieve a more satisfactory prediction of the SOM content, and the RF model had better accuracy than the PLSR model. The SOM content prediction model established by Boruta algorithm combined with the RF model performed best with 23 variables and the model achieved the coefficient of determination (R²) of 0.78 and the residual prediction deviation (RPD) of 2.38. The Boruta algorithm effectively removed redundant information and optimized the optimal wavelengths to improve the prediction accuracy of the estimated SOM content. Therefore, combining vis-NIR spectroscopy with machine learning to estimate SOM content is an important method to improve the accuracy of SOM prediction in arid land.  相似文献   

用Shenk's方法提高芥酸NIR模型预测精度     

陈斌  吴继明 《农业机械学报》2007,38(8)

在光谱测量的过程中,由于光谱仪器本身的精度和测量环境等因素,经常会出现光谱的漂移、线性或非线性改变。以基于近红外光谱分析建立菜籽油中芥酸预测模型为例,将多元校正Shenk's算法用于修正同台仪器测量的光谱差异,大大提高了校正模型的预测精度。结果表明,对于光谱修正后再建模预测,预测均方差从2.263下降到1.569,平均相对误差从4.6%下降到3.218%,相关系数也由0.780提高到了0.913,模型的预测精度显著提高。  相似文献   

基于模拟退火算法的供水泵站优化调度     

陈虹  刘正意  史旺旺 《排灌机械》2003,21(5):34-36

采用模拟退火算法用于供水系统的多泵组合和变频调节的复杂的优化计算，并给出了优化计算的编码、译码和能量函数表达式。计算结果表明，模拟退火算法非常适用于既有离散量又有连续量的供水系统的非线性优化中。  相似文献   

基于遗传算法的制造质量控制多目标的优化     

亓四华  费业泰 《农业机械学报》2006,37(6):110-112,116

根据零件加工过程的加工和测量能力,给出了制造质量控制多目标的优化数学模型.针对遗传算法的特点,提出了基于遗传算法的制造质量控制多目标的优化方法.算例计算结果表明,遗传算法在制造质量控制多目标的优化方面具有良好的应用前景.  相似文献