Unilateral Conformance Proportions in Balanced and Unbalanced Normal Random Effects Models

Conformance proportion is the proportion of a performance characteristic of interest that falls within a prespecified acceptance region, which has been used in various applications. In this article, a simple closed-form interval estimation, based on Student’s t statistic, is proposed for unilateral conformance proportions in balanced and unbalanced random-effects models. Two real datasets are analyzed to illustrate the proposed method, whose performance is also evaluated through detailed simulation studies. The simulation results reveal that the empirical coverage probabilities for upper confidence limits of the method are sufficiently close to the nominal values, but those for lower confidence limits appear to be slightly less than the nominal level. Furthermore, a bootstrap-based calibration for both upper and lower confidence limits is provided to have empirical coverage probabilities closer to the nominal level. This article has supplementary material online.     

Slurry acceptance mapping of Northern Ireland for run-off risk assessment

Using geographic information system techniques, hydrology of soil types (HOST) classes were combined with slope, rockiness, flood hazard and soil moisture deficit classes within a risk matrix to produce a slurry acceptance map for Northern Ireland (NI) on a 50 m grid. Moreover, due to the whole territory of NI being designated as a nitrate vulnerable zone, a nitrates action programme is to be implemented across the region in the near future and this is likely to restrict slurry applications to the growing season. To assess the risk classes associated with slurry applications during the growing season, an additional slurry acceptance map for NI was created in which the HOST factor was excluded from the analysis. The maps created showed that, for the period January–December, the majority (80%) of agricultural soils in NI were in the severe risk category following application of 50 m³ ha^?1 of slurry. However, this proportion was reduced to only 29% when the same volume of slurry was applied during the growing season, when the soils were not saturated and significant rainfall was not received in the period immediately after slurry application.     

基于可见光波段无人机遥感的植被信息提取

无人机遥感具有使用成本低、操作简单、获取影像速度快、地面分辨率高等传统遥感无法比拟的优势。该文通过分析仅含红光、绿光和蓝光3个可见光波段的无人机影像中植被与非植被的光谱特性,同时结合健康绿色植被的光谱特征,借鉴归一化植被指数NDVI的构造原理及形式,提出了一种综合利用红、绿、蓝3个可见光波段的归一化植被指数——可见光波段差异植被指数VDVI(visible-band difference vegetation index)。与其他基于可见光波段的植被指数,如过绿指数EXG(excess green)、归一化绿红差值指数NGRDI(normalized green-red difference index)、归一化绿蓝差值指数NGBDI(normalized green-blue difference index)和红绿比值指数RGRI(red-green ratio index)以及仅用绿光波段的提取结果进行对比分析,结果表明:VDVI植被提取精度高于其他可见光波段植被指数,且阈值在0附近,较易确定。为了验证VDVI的适用性与可靠性,选取与试验影像同一时期拍摄但不同区域的另一影像使用同样的方法提取植被信息。结果表明:VDVI对于仅含可见光波段无人机遥感影像的健康绿色植被信息具有较好的提取效果,提取精度可达90%以上,适用于仅含可见光波段无人机遥感影像的健康绿色植被信息提取。     

采用全景技术的机器视觉测量玉米果穗考种指标

为了在利用图像技术无损考察玉米果穗形态指标时,能够利用一幅图像显示整个玉米果穗的外形,从而减少多幅图像拼接产生的重叠和处理不便,该文提出一种新的基于机器视觉的玉米果穗考种方法与配套装置,首先拍摄旋转玉米果穗图像序列,应用SIFT（scale invariant feature transform）算法获取图像特征点,对特征点随机采样计算单应矩阵并进行一致性检测排除外点,将前后2帧图像注册到同一坐标系。然后采用动态规划法寻找前后2帧拼接图像的缝合线,按缝合线切割图像,以图像模板高斯滤波权值融合缝合线两侧图像消除曝光差异。依次拼接、融合图像序列生成果穗全景图。对果穗全景图进行考种指标检测,试验结果表明：基于机器视觉的测量值与人工测量方式不存在显著性差异（显著水平α=0.05）,该文所述方法可满足自动化考种的需求。     

A restricted selection index method based on eigenanalysis

Selection indices, used in animal and plant breeding to select the best individuals for the next breeding cycle, are based on phenotypic observations of traits recorded in candidate individuals. The restrictive selection index (RSI) facilitates maximizing the genetic progress of some characters, while leaving others unchanged. Recently a selection index (SI) was proposed based on the eigen analysis method (ESIM), in which the first eigenvector (from the largest eigenvalue) is used as the SI criterion, and its elements determine the proportion of the trait that contributes to the SI. However, the current ESIM, which has two main limitations, is based on the assumption that the vector of coefficients of the index is equal to the genotypic variance-covariance matrix among the traits multiplied by the vector of economic weights, and does not allow one to restrict the number of traits. In this study, we develop a more general ESIM that has two main features, namely, it makes no assumption concerning the coefficients of the index and it can be generalized to a restrictive ESIM (RESIM). We use two datasets to illustrate the theoretical results and practical use of ESIM and RESIM, and to compare them with standard unrestrictive and restrictive selection indices. The main advantages of RESIM over traditional unrestrictive and restrictive SIs are that its statistical sampling properties are known; its selection responses are equal to or greater than those estimated from the traditional restrictive SI; and it does not require economic weights and thus can be used in practical applications when all or some of the traits need to be improved simultaneously (traditional SIs cannot improve several traits simultaneously if economic weights are not available). Finally, we prove that the coefficients of the traditional RSI belong to the space generated by the eigenvectors of RESIM.     

基于无人机高光谱遥感的冬小麦叶面积指数反演

叶面积指数(leaf area index,LAI)是评价作物长势和预测产量的重要依据。光谱特征信息作为高光谱遥感的突出优势在追踪LAI动态变化方面极其重要;然而,围绕光谱特征信息所开展的无人机高光谱遥感反演作物LAI的相关研究鲜有报道。该文利用ASD Field Spec FR Pro 2500光谱辐射仪(ASD Field Spec FR Pro 2500 spectroradiometer,ASD)和Cubert UHD185 Firefly成像光谱仪(Cuber UHD185 Firefly imaging spectrometer,UHD185)在冬小麦试验田进行空地联合试验,基于获取的孕穗期、开花期以及灌浆期地面数据和无人机高光谱遥感数据,估测冬小麦LAI。该文选择同步获取的冬小麦冠层ASD光谱反射率数据作为评价无人机UHD185高光谱数据质量的标准,依次从光谱曲线变化趋势、光谱相关性以及目标地物光谱差异三方面展开分析,结果表明458~830 nm(第3~96波段)的UHD185光谱数据可靠,可使用其探测冬小麦LAI,这为今后无人机UHD185高光谱数据的使用提供了参考。该文研究对比分析了UHD185数据计算的红边参数和光谱指数与冬小麦LAI的相关性,结果表明:12种参数中比值型光谱指数RSI(494,610)与LAI高度正相关,是估测LAI的最佳参数;基于比值型光谱指数的对数形式lg(RSI)构建的线性模型展现出lg(RSI)与lg(LAI)较优的线性关系(决定系数R2=0.737,参与建模的样本个数n=103),且lg(LAI)预测值和lg(LAI)实测值高度拟合性(R2=0.783,均方根误差RMSE=0.127,n=41,P0.001);该研究为利用无人机高光谱遥感数据开展相关研究积累了经验,也为发展无人机高光谱遥感的精准农业应用提供了参考。     

Comparing pivotal and REML-based confidence intervals for heritability

Heritability quantifies the extent to which a physical characteristic is passed from one generation to the next. From a statistical perspective, heritability is the proportion of the phenotypic variance attributable to (additive) genetic effects and is equal to a function of variance components in linear mixed models. Relying on normal distribution assumptions, one can compute exact confidence intervals for heritability using a pivotal quantity procedure. Alternatively, large-sample properties of the restricted maximum likelihood (REML) estimator can be used to construct asymptotic confidence intervals for heritability. Exact and asymptotic intervals are compared loineye muscle area measurements and balanced one-way random effects models having groups of correlated responses. In some cases the two interval methods yield vastly different results and the REML-based confidence interval does not maintain the nomiral coverate value even for seemingly large sample sizes. For finite sample size applications, the validity of the REML-based procedure depends on the correlation structure of the data.     

基于三角模型的喀斯特地区土地利用系统健康评价

喀斯特地区作为一种典型的土地生态环境区域,对其土地利用系统健康状态和趋势进行评价是诊断由人类活动引起的土地利用系统破坏和退化程度的重要手段。该文在界定土地利用系统健康评价概念的基础上,通过土地利用系统的结构性指数、功能性指数和效益指数构建评价指标体系,建立土地利用系统健康评价的三角模型,并对2005-2012年贵阳市土地利用系统的健康状态和趋势进行了分析和评价,提出了优化土地利用系统健康状态的路径。结果表明:贵阳市土地利用系统的健康水平先后经历了不健康、亚健康、初级健康和中级健康4个状态阶段,具有逐渐向高级健康状态发展的趋势,在未来应该优化土地资源配置,提升经济建设基础保障水平并结合自然优势,充分利用土地发展绿色生态经济,充分利用先进信息技术水平,建立土地利用系统健康状态预警系统以优化土地利用系统的健康水平。该研究能够为生态脆弱区的土地利用及保护提供理论和实践参考。     

基于静态与动态空间面板模型分析城镇化对雾霾的影响

该研究以中国30省区为研究对象,首先考察了雾霾污染的空间效应。全局Moran’s I指数为0.3875,中国雾霾污染存在着空间集聚。Moran’s I指数散点图显示中国雾霾污染存在着正的空间自相关,绝大部分省区位于高-高集聚和低-低集聚。然后,基于雾霾污染的空间效应,建立静态与动态空间面板计量经济学模型,实证考察了城镇化、能源强度、交通压力等对雾霾污染的影响。城镇化与雾霾污染之间存在环境库兹涅茨曲线;交通压力每上升一个百分点,将使雾霾污染上升0.2075个百分点。从效应的分解来看,该地区以及全局城镇化与雾霾污染之间存在环境库兹涅茨曲线。人均GDP的间接效应、总效应显著为负,该地区人均收入的上升可以使相邻地区的雾霾污染下降,并且会减少全局雾霾污染。能源强度下降会减轻本地区雾霾污染程度,但会导致相邻地区雾霾污染上升。能源消费结构直接效应为正,间接效应与总效应显著为正,煤炭消费比例的下降不但会减少本地区雾霾污染,也会显著抑制相邻地区的雾霾污染,进而减少全局雾霾污染。交通压力的直接效应显著为正,但间接效应显著为负,交通压力的上升会明显加重本地区雾霾污染程度,然而相邻地区交通压力上升会抑制本地区雾霾污染。动态空间杜宾面板计量模型中被解释变量滞后一期系数高达0.6114,且通过了1%水平下的显著性检验,中国雾霾污染存在时空依赖。动态空间面板计量模型比静态更为合适,估计结果更为准确,遗漏因素对雾霾污染的影响也很重要。     

Optimal sample size for composite sampling with subsampling, when estimating the proportion of pecky rice grains in a field

The proportion of pecky rice grains has been estimated empirically using composite sampling with subsampling. The procedure can be summarized as follows: (1) A fixed number of rice plants, n ₁, are drawn at random in the paddy field; (2) all of the rice grains in the collected rice plants are mixed well to form a composite; (3) a portion of the grains, n ₂, is drawn at random from the composite; and (4) the collected grains are examined by eye to estimate the proportion of pecky rice grains. We propose a method for determining the optimal sample size in estimating the proportion of defective items by this type of composite sampling with subsampling. Spatial heterogeneity in the proportion of defective items is included in the estimation. We use Taylor’s power law to describe the density-dependent change of spatial heterogeneity. In controlling the precision of the estimate, we use the relative precision, D, which is defined by the coefficient of variation of the estimated proportion. We propose a rejection procedure in which the product is rejected if the estimate of proportion with D=0.25 is larger than a predetermined tolerable threshold of proportion. We also consider another control criterion in which the consumer’s risk, \, is controlled by a zero-tolerance method. Finally, we examine the relationship between the two control criteria.     

土壤特征微团聚体的组成比例与肥力评价

以棕壤为例研究了15对不同肥力水平的典型棕壤、棕壤型水稻土的特征微团聚体（＜10m和＞10m）的组成比例，结果表明该比例即微团聚体（＜10m）／微团聚体（＞10m）可成为土壤肥力水平的一个综合指标。以该指标为标准的典型棕壤和棕壤型水稻土肥、瘦地区分界数分别为0.25和0.35，小于此二值分别为各自肥地，反之亦反。土壤培肥措施可使肥、瘦地特征微团聚体的比例降低并提高土壤肥力水平或根本改变瘦地肥力实质。     

Estimating uncertainties in individual eddy covariance flux measurements: A comparison of methods and a proposed new method

We present a review of four methods that are currently and formerly used to estimate random flux measurement uncertainties in eddy covariance instrument systems, examining their theoretical basis. In our review, we illustrate a few of the strengths and weaknesses of each, paying particular attention to the explicit and implicit assumptions made. We then evaluate the practicality, ease of use, and relative performance for the methods reviewed. We also describe a new method of random flux uncertainty estimation that is designed to only be sensitive to random instrument noise, and compare its predictions with other methods on both real and synthetic data. We conclude that our new method is a good complement to the others examined. We also suggest that when our proposed technique is used with one or more of the other methods, new information is obtained about how contributions to the total uncertainty are distributed among their various causes.     

Shelf-life modeling of bakery products by using oxidation indices

The aim of this work was to develop a shelf-life prediction model of lipid-containing bakery products. To this purpose (i) the temperature dependence of the oxidation rate of bakery products was modeled, taking into account the changes in lipid physical state; (ii) the acceptance limits were assessed by sensory analysis; and (iii) the relationship between chemical oxidation index and acceptance limit was evaluated. Results highlight that the peroxide number, the changes of which are linearly related to consumer acceptability, is a representative index of the quality depletion of biscuits during their shelf life. In addition, the evolution of peroxides can be predicted by a modified Arrhenius equation accounting for the changes in the physical state of biscuit fat. Knowledge of the relationship between peroxides and sensory acceptability together with the temperature dependence of peroxide formation allows a mathematical model to be set up to simply and quickly calculate the shelf life of biscuits.     

基于GIS的帽儿山景观生态综合评价

景观生态综合评价对区域区划有重要的意义,以黑龙江帽儿山为例,以2006年林相分布图、Landsat TM遥感数据、地形图、二类调查数据和其他数据材料为数据源,以GIS为技术手段,选取景观类型破碎度、景观形状指数、土壤侵蚀类型、地形因素（坡度）、土地利用类型、植被盖度指数与气象因子（年降水量）7个指标对研究区域进行景观生态综合评价,在此基础上进行景观生态区划。研究结果表明:（1）全面分析景观生态综合评价指数并进行分级处理和景观区划,分为Ⅰ、Ⅱ、Ⅲ、Ⅳ和Ⅴ级区域,分别代表好、较好、中、较差和差5个级别;（2）不同景观生态综合评价区域面积所占比例的排列顺序为:Ⅱ>Ⅲ>Ⅳ>Ⅰ>Ⅴ,Ⅱ级区域所占的比例最大,在整个研究区域中占据绝对的优势,区域景观生态质量属于较好水平;（3）景观生态质量垂直分异明显,第一、二高程带的景观质量较好,Ⅱ级区域在一、二高程带所占比例较大,在第二高程带达到最大,第三、四和五高程带的景观质量较差。可见基于DEM模型和景观生态综合评价揭示景观生态质量的空间特征。     

自动基流分割方法在黄土区流域的应用研究

基流是河川径流在枯水季节的主要径流来源.由于难以通过实测方法获得基流量数据,选择适合的基流分割技术对于基流研究至关重要.利用黄土区6个流域的多年径流量资料,选取PART法、滤波法及滑动最小值法等目前广泛使用的自动基流分割方法对区域内河流的基流量进行了分割,以检验自动基流分割方法在本地区的适用性,并应用选定的基流分割方法对黄土区流域的基流特点做了简单分析.研究结果表明,3种方法所获得的基流指数值有所差异,滤波法分割的基流过程与实际基流状况更为相符.因此,滤波法可作为黄土区流域基流的最优分割方法.应用滤波法得到的研究流域基流占总径流比重为37%～64%,而基流量在近50 a中呈现逐渐降低趋势.     

权重约束AdaBoost鱼眼识别及改进Hough圆变换瞳孔智能测量

针对传统鱼眼瞳孔直径测量方法耗时、耗力,且数据主观性强的问题,该文提出基于权重约束AdaBoost和改进Hough圆变换的鱼眼瞳孔直径智能测量方法。首先,利用工业相机采集实验板上的鱼图像,从正负鱼眼图像样本中训练出基于权重约束AdaBoost算法的鱼眼分类器;然后,采用该分类器对试验图像进行检测,将检测到的鱼眼局部图从整体图中分离出来;最后,采用改进的Hough圆变换检测出鱼眼的瞳孔,并计算得到瞳孔直径。对100条金鲳鱼进行试验,鱼眼分类精度达97.1%,瞳孔正确检测率达94.2%,相比改进前分别提升了1.7个百分点和10.5个百分点,与人工测量瞳孔直径值的平均偏差为6.5%,比改进前低了5.9个百分点,总的平均测量时间为324.371 ms,比改进前减少了10.707 ms。试验证明:该文提出的方法能够精确、实时、自动地测量出鱼眼瞳孔的直径,有效避免了传统测量方式的复杂性和测量数据的主观性,可为鱼体生长状况评估、良种选育提供重要参考。     

A Baseline Category Logit Model for Assessing Competing Strains of <Emphasis Type="Italic">Rhizobium</Emphasis> Bacteria

In this paper we describe novel methodology for evaluating competition among strains of Rhizobium bacteria which can be found naturally occurring in or can be introduced into soil. Rhizobia can occupy nodules on the roots of legume plants allowing the plant to ‘fix’ atmospheric nitrogen. Our model defines competitive outcomes for a community (the multinomial count of nodules occupied by each strain at the end of a time period) relative to the past state of the community (the proportion of each strain present at the beginning of the time period) and incorporates this prior information in the analysis. Our approach for assessing competition provides an analogy to multivariate methods for continuous responses in competition studies and an alternative to univariate methods for discrete responses that respects the multivariate nature of the data. It can also handle zero values in the multinomial response providing an alternative to compositional data analysis methods, which traditionally have not been able to facilitate zero values. The proposed experimental design is based on the simplex design and the model is an extension of multinomial baseline category logit models that includes multiple offsets and random terms to allow for correlation among clustered responses. Supplemental materials for this article are available from the journal website.     

基于压力-状态-响应的熵权-物元水生态文明评价模型

为了对区域水生态文明水平进行评价,针对目前水生态文明评价存在的问题,探讨水生态文明的内涵和评价方法.运用压力-状态-响应模型(press-state-response,PSR)提出由3类要素20种指标所组成的水生态文明评价指标体系;利用客观的熵权法求指标权重,减少了人为主观性对评价结果的干扰;利用物元分析方法有效解决了评价指标的模糊性和不相容性等问题,通过构造水生态文明的经典物元和节域物元,分析各个指标对应评价等级的关联度,构建了基于PSR的熵权-物元水生态文明综合评判模型.以济南市南部郊区为例进行研究,求得2010、2013、2015年水生态文明评价结果并对指标进行灵敏度分析,结果表明济南郊区水生态文明水平总体在逐渐提升,但水生态系统的压力没有明显减小,减少氨氮和化学需氧量污染物的排放是提升当地水生态文明水平的关键措施.该文模型能够揭示水生态文明现实状态和存在的问题,评价方法可供类似区域开展水生态文明评价参考.     

全光谱匹配算法在苹果分类识别中的应用

为进一步提高光谱匹配准确率,该研究对杰卡德相似性原理（jaccard similarity coefficient,JSC）进行改进并提出新的光谱相似度的计算方法。同时,对光谱进行一阶导数二值化,以保证改进后的算法适用于光谱的匹配。此外,对不同光谱分辨率对该算法的影响进行了研究。试验样本选用阿克苏红富士、山东红将军、陕西红富士和陕西金帅4个品种的苹果进行算法能力验证,在2～128 cm-1之间,共7个不同水平的分辨率上进行比较。试验结果表明：该研究提出的算法正确分类识别率为94.5%;研究提出算法在8或16cm-1分辨率水平下取得最佳分类识别结果。因此,基于JSC的全谱匹配算法在光谱数据库系统中的应用将有助于光谱查询精度的提高。     

Probabilistic approach to the calculation of soil erosion loss

An algorithm was proposed for the simulation of water erosion as a stochastic process. Two concepts were used: the random single event (e.g., rainfall) and the implementation of a random process as a series of random single events during a long time period. The Monte Carlo method and previously developed and substantiated equations for rain and snow melt erosion were used for the numerical simulation of random single events. The simulation resulted in a series of values for the soil loss during the specified time period, from which the probability distribution of the soil loss during this period could be assessed. The testing results for the chernozemic soils of the Central Chernozemic region showed that the error of the soil loss calculation was 13% during 200 years of land use. It was shown that the SCS equation developed for the United States’ conditions can be used to calculate the rainfall runoff in the Central Chernozemic region of Russia. Problems that cannot be solved using deterministic models and the available observation data can be solved on the basis of the obtained probability distributions.