二次响应面回归模型用遗传算法探索最优试验条件

目的 探讨多因素、多水平试验中最优试验条件的确定方法。方法 以二次响应面回归模型为目标函数 ,用遗传算法搜索最优试验条件。结果 在试验范围内 ,遗传算法确定的最优试验条件精度较高 ,且可预测响应变量的水平 ;若根据实际的可行性 ,外延因素的搜索范围 ,为研究提供新的试验方向。结论 模型与遗传算法结合 ,为多因素、多水平试验中最优试验条件确定提供了精度高 ,信息量大的新方法。

响应面-主成分分析法优化鲜湿米线配方

为研制一款兼具功能性和食用品质的杂粮鲜湿米线,此试验以籼米、鹰嘴豆(Cicer arietinum L.)和燕麦米(Avena sativa L.)为主要原料,食盐、黄原胶为品质改良剂,利用单因素试验和Box-Behnken试验设计,并结合主成分分析法优化了鲜湿米线配方。结果表明,前5个主成分累计贡献率达到89.733%,能够比较全面反映米线综合指标信息。利用主成分分析法得到的规范化综合得分建立响应面回归模型方差分析,拟合度较好(P=0.00012,R^(2)=0.9460),预测的最优配方条件为鹰嘴豆燕麦米添加比例2∶5、食盐添加量3%、黄原胶添加量0.5%,在该条件下米线规范化综合得分为0.9573,与理论综合评分没有显著差异(P>0.05)。此研究为功能性食品多指标开发提供一定参考。

采摘机械臂结构参数对其工作空间的影响

工作空间是评价机械臂工作性能的一个重要指标。首先,采用Adams运动仿真和图解法相结合的方法对采摘机械臂的工作空间进行了模拟,较为精确地得到了机械臂的工作空间边界;其次,在利用Matlab绘制出采摘机械臂工作空间散点图的基础上,采用凸包函数进行处理,生成一个较为精准的包络空间来描述该工作空间的体积;进而分析了机械臂结构参数对工作空间体积的影响,为机械臂的结构设计和优化提供了理论依据;最后,建立了可用于预测采摘机械臂工作空间以及设计方案调整的线性响应回归模型,并通过试验数据验证了该模型的准确性。

Comparative Study of Response Surface Designs with Errors-in-Variables Model

This paper investigates the scaled prediction variances in the errors-in-variables model and compares the performance with those in classic model of response surface designs for three factors.The ordinary least squares estimators of regression coefficients are derived from a second-order response surface model with errors in variables.Three performance criteria are proposed.The first is the difference between the empirical mean of maximum value of scaled prediction variance with errors and the maximum value of scaled prediction variance without errors.The second is the mean squared deviation from the mean of simulated maximum scaled prediction variance with errors.The last performance measure is the mean squared scaled prediction variance change with and without errors.In the simulations,1 000 random samples were performed following three factors with 20 experimental runs for central composite designs and 15 for Box-Behnken design.The independent variables are coded variables in these designs.Comparative results show that for the low level errors in variables,central composite face-centered design is optimal;otherwise,Box-Behnken design has a relatively better performance.

An improved adaptive response surface method for structural reliability analysis

The response surface method(RSM) is one of the main approaches for analyzing reliability problems with implicit performance functions.An improved adaptive RSM based on uniform design(UD) and double weighted regression(DWR) was presented.In the proposed method,the basic principle of the iteratively adaptive response surface method is applied.Uniform design is used to sample the fitting points.And a double weighted regression system considering the distances from the fitting points to the limit state surface and to the estimated design points is set to determine the coefficients of the response surface model.Compared with the conventional approaches,the fitting points selected by UD are more representative,and a better approximation in the key region is also observed with DWR.Numerical examples show that the proposed method has good convergent capability and computational accuracy.

集装箱硫酰氟熏蒸灭蟑的量效学研究

目的研究广谱熏蒸剂——硫酰氟熏蒸灭蟑的最佳剂量与时间的关系。方法采用静式呼吸道吸入染毒法对各组德国小蠊进行熏蒸处理,观察其中毒症状与死亡情况,运用二次响应面回归模型对实验数据进行拟合及预测,并经过现场模拟验证。结果模型方差分析结果显示,响应面模型有统计学意义(F=75.12,P<0.0001),总决定系数R2=0.7848,模型的一次项、二次项与交叉项均有统计学意义,其决定系数分别为0.1493、0.1902和0.4453;以该模型预测所得的硫酰氟灭蟑剂量与作用时间值为依据进行现场模拟试验,灭蟑率均达到100%。结论根据本次研究基本确定了硫酰氟熏蒸灭蟑的最佳剂量与作用时间的关系,为今后集装箱熏蒸工作中设定正确的投药量与时间提供了科学依据。