基于支持向量机的储粮仓壁动态侧压力预测模型

影响筒仓动态侧压力的影响因素十分复杂,如何全面考虑影响因素,高效、简单地预测筒仓动态侧压力是重要问题。针对此问题,尝试提出了基于支持向量机的预测模型。首先,将影响因素进行归一化处理,将归一化后的数据作为预测模型的输入向量,筒仓动态侧压力作为预测模型的输出向量;其次,以400组PFC模拟数据作为训练样本,运用交叉验证和网格搜索法寻优获得最优支持向量机参数,最终建立基于SVM的筒仓动态侧压力预测模型,并对105组PFC模拟数据进行筒仓动态侧压力预测。结果表明:SVM预测模型的均方误差MSE小于0.0005,相关系数R;大于0.98,模型具有较高的准确率和较好的泛化性能。将模型试验、数值模拟、公式计算与预测数据进行对比分析,结果拟合良好;利用该模型验证筒仓动态侧压力随着相关参数的变化趋势,结果与前人研究结果相一致。该预测模型与传统方法相结合对筒仓动态侧压力进行研究可行性较高,可为筒仓动态侧压力预测、影响因素研究提供一种新的方法。     

垂直流人工湿地脱氮过程的生态动力学模拟与分析

根据实验性模拟垂直流人工湿地进、出水数据和系统动力学的研究方法,运用STELLA系统动力学软件对模拟垂直流人工湿地脱氮过程进行建模分析。STELLA分析结果表明:构建的STELLA动力学模型能较准确地模拟垂直流人工湿地对废水中NO-3-N、NH+4-N、TN的去除率,但对废水中有机氮去除率的模拟性较差;在运行正常的情况下,该模型可以对垂直流人工湿地系统氮的去除过程进行描述,并可为其处理出水浓度变化的预测提供理论依据。     

The derivation of grassland vegetation types on the basis of site and land use characteristics

This study derives grassland communities from site, climate and land use characteristics, allowing yield estimation within the framework of model scenarios. Based on the dominant species, about 450 relevés, primarily of extensively used grassland from four regions of the North-East German lowlands, were classified into vegetation types using a cluster analysis. These types were then reclassified to known phytosociological communities. The relationship between the vegetational composition and the abiotic explanatory variables were verified by a discriminant analysis. The water supply level proved to be the most important factor influencing grassland vegetation. The impact of historical land use (especially the persistence of formerly sown species) reduced prognostic quality.     

Compatibility of the ammonium lactate (AL) and sodium bicarbonate (Olsen) methods for determining available phosphorus in Swedish soils

Abstract

Plant-available P was first extracted in soils 114 years ago and a number of different analytical methods have since been developed, but for good reasons none of these methods has been adopted as a standard for all soils. With increasing cooperation within research, there is a need to harmonise the interpretation of analytical data for fertiliser recommendations, research, and environmental control. This paper evaluates the compatibility of the Swedish standard ammonium lactate (P_AL) method and the widely used Olson's sodium bicarbonate (P_Ols) method in 82 topsoil samples taken from Swedish long-term soil fertility field trials. The P_AL-values were usually larger than P_Ols, with a mean P_AL/P_Ols quotient of 2.30±1.04 (0.67–6.58). The P_AL and P_Ols means and ranges were 126±89 (5–360) and 55.1±33 (3.1–122.8) mg P kg^?1 dry soil, respectively. Stepwise multiple linear regression analysis was used to evaluate the relationship between P_AL and P_Ols and how this relationship was affected by clay content, pH, and soil organic carbon content (SOC). After statistical transformation, it emerged that the square root of clay content (17.4%±13.82, range 1–54.4) and pH (6.45±0.54, range 5.5–7.7) significantly affected the relationship at partial R ²-values of 2 and 12%, respectively, while ln(SOC) (2.54%±1.21, range 1–6.03) did not, apparently due the narrow range. The regressions of predicted vs. measured values explained 95 and 94% of the variation in P_AL and P_Ols, respectively. The mean deviation of predicted compared with measured values was 21.3 and 8.3 mg P kg^?1 dry soil for P_AL and P_Ols, respectively, corresponding to 20 or 19% of the measured values. We conclude that a data set consisting of P_AL-values can be converted into P_Ols-values and vice versa with reasonably high accuracy when accounting for clay content and pH.     

基于可见/近红外光谱技术的土壤总磷分析研究

Overabundance of phosphorus (P) in soils and water is of great concern and has received much attention in Florida, USA. Therefore, it is essential to analyze and predict the distribution of P in soils across large areas. This study was undertaken to model the variation of soil total phosphorus (TP) in Florida. A total of 448 soil samples were collected from different soil types. Soil samples were analyzed by chemical reference method and scanned in the visible/near-infrared (VNIR) region of 350--2 500 nm. Partial least squares regression (PLSR) calibration model was developed between chemical reference values and VNIR values. The coefficient of determination (R²) and the root mean squares error (RMSE) of calibration and validation sets, and the residual prediction deviation (RPD) were used to evaluate the models. The R² in calibration and validation for log-transformed TP (log TP) were 0.69 and 0.65, respectively, indicating that VNIR calibration obtained in this study accounted for at least 65% of the variance in log TP using only VNIR spectra, and the high RPD of 2.82 obtained suggested that the spectral model derived in this study was suitable and robust to predict TP in a wide range of soil types, being representative of Florida soil conditions.     

番茄褪绿病毒病预测预报模型的建立

研究烟粉虱传播番茄褪绿病毒Tomato chlorosis virus (ToCV)的发生规律,建立其预测预报模型,能够指导田间早期有效防治。本研究于2014年－2018年每年采集山东寿光蔬菜基地大棚番茄和杂草的植株叶片,并收集植株上携带的所有烟粉虱,以健康番茄、杂草叶片和室内饲养的健康烟粉虱为阴性对照;实验室ToCV侵染性克隆接种的感病叶片以及从感病叶片上获毒的烟粉虱为阳性对照,将采集的样品带回实验室进行检测和鉴定等试验。根据病情发生规律,建立了番茄褪绿病毒病的预测预报模型,模拟所得方程为:Y=2.570+0.089X4-7.548X7,其中Y为11月份番茄褪绿病毒病发生率,X4为采集的样品上平均每株所携带的烟粉虱数量,X7为采集的田间杂草的带毒率。预测模拟结果显示,烟粉虱数量以及杂草的带毒率与番茄褪绿病毒病的发生率极显著正相关,回归检测结果历史符合率为96.8%以上。明确了影响番茄褪绿病毒病发生的影响因子,基于烟粉虱数量以及杂草的带毒率,构建了病害预测预报模型。研究结果有助于及时发现番茄褪绿病毒病并采取相应预防措施。     

冷藏大黄鱼货架期预测模型的建立和评价

建立和验证了用于预测冷藏养殖大黄鱼(Pseudosciaena crocea)鲜度和剩余货架期的特定腐败菌生长动力学模型。感官、VBN评价和微生物生长动态分析表明,大黄鱼在0℃、5℃、10℃时有氧贮藏的特定腐败菌假单胞菌(Pseudomonasspp.)在感官货架期终点菌数NS(CFU.g-1)的对数(lgNS)平均值为6.48±0.14。将获得的假单胞菌在0℃、5℃、10℃的生长实验值用于建立生长动力学模型,结果显示,最大菌数Nmax(CFU.g-1)受贮藏温度的影响不大,在3种温度下lgNmax为7.18±0.031。温度对最大比生长速率(μmax)和延滞时间(Lag)的影响,采用Belehradek方程描述,呈现良好线性关系,R2分别为0.991和0.996。获得0~10℃有氧贮藏大黄鱼的剩余货架期(SL)预测模型为:SL=1/(0.093 8T+0.086)2-(7.18-lgN0)/[2.718×(0.009 6T+0.082 8)2]×ln-ln(6.48-lgN0)/(7.18-lgN0)-1(T为贮藏温度,N0为初始假单胞菌数)。用大黄鱼贮藏在3℃和8℃的货架期实测值验证建立的模型,预测值和实测值的相对误差分别为-8.89%和-6.59%,显示建立的模型可以快速可靠地实时预测0~10℃有氧贮藏大黄鱼的鲜度和剩余货架期。     

莱州湾海蜇资源预报方法的初步研究

本文根据1996年莱州湾海蜇资源调查结果,应用面积法对资源量和渔场进行了预报。渔业生产结果表明,这种预报方法是可行的,而且准确度较高。     

Finite element modeling and multi-software co-simulation in automobile EMC prediction

For general software in the limitation of large and complex structures’ modeling, this article proposes a multi-software co-simulation technology. Hypermesh is a pre-processing software which can high-quality import and triangular CAD-models, taking advantage of this, the CAD-model of the car is meshed in Hypermesh. Using Matlab,the node coordinates data of each component’s elements are extracted from the grid data file outputted by Hypermesh, and are exported in the form of text file for Hfss to read.VBS program is used to build the finite element model, which is written in Matlab, then runs in Hfss to read the node coordinates data and form the initial triangular-mesh model of the Automobile. Considering only the interference of the ignition system power line’s common-mode current we simulated and analyzed the electric field distribution inside and outside of the automobile.This modeling method has a strong commonality ,and is a good reference for automobile EMC simulation modeling.