贝叶斯矩法在粮食安全预警中的作用

BMOM(BayesianMethodofMoment)是著名经济学家、芝加哥大学的教授ArnoldZellner在20世纪90年代提出的贝叶斯矩法,Zellner教授成功地将其应用于统计分析的经典问题,并获得了与原有结论相同的结果,但所需条件宽松。同时,他又将这一方法应用于宏观经济的预测和经济发展转折点的预测,都取得了很好的结果。鉴此,文章就BMOM方法在粮食安全预警系统中的应用进行了探讨。     

从美式快餐看中式快餐

随着经济的发展和社会的进步,人 们正逐步地向现代化的生活方式迈进,快餐这种制售快捷、服务简便、价格适中的大众饮食,正以其锐不可挡之势得到迅速发展。然而近年来,由于美国快餐的大量涌入,使中国快餐业受到前所未有的冲击。那么,中国这一世界上最大的快餐市场将由谁来主宰？美国快餐何以势不可挡？中国快餐差距何在？这些问题已越来越引起人们的关注。笔者就相关问题做以下初步探索。 一．美国快餐业的经营特点 提到美国快餐,人们自然会想到“麦当劳”。麦当劳快餐店是世界上最大的食品服务组织,麦当劳公司、快餐店经理、特许经…     

食品标签信息对消费者购买决策的影响研究——以婴幼儿食品为例

基于Hicks消费者剩余的CV形式,构建信息关注度、信息源信任度、信息充分度的Logit食品标签信息影响决策模型.通过在北京市发放问卷并回收、统计数据及分析,研究发现:消费者在购买婴幼儿食品时,对食品标签上的食品生产日期和保质期、营养成分、配料清单、食用指导注意等信息的关注度高,影响显著;对食品品牌、生产厂家及厂址、使用方法及贮藏、安全标识等信息关注度低,影响不显著;消费者对政府机构、婴幼儿医师和学者、亲朋及名人代言等信息源的信任度高,对购买决策影响显著;消费者对非政府机构和食品企业等信息源的信任度低,对购买决策影响不显著;食品标签信息充分度对消费者获得高质量信息、降低风险和提高决策准确度等起到的作用很大;消费者的性别、年龄、收入、受教育程度等对购买决策影响显著;相对于女性而言,食品标签信息对男性消费者的购买决策更有影响.     

Estimation of a Composite Food Demand System for the United States

This study develops statistical procedures for computing the parameters of a complete demand system. A constrained maximum likelihood method has been applied, and parametric restrictions derived from classical demand theory are introduced by a substitution approach. The procedures are then applied to U.S. data for estimating a composite food demand system covering 12 food categories and one nonfood sector.     

农业及粮食安全问题

一、农业安全是经济安全的基础农业安全是指农业能基本满足社会日益增长的食品需求 ,具有较强的竞争能力和创收能力 ,处于可持续发展状态。农业不安全是指农业不能够提供社会需要的初级产品 ,或无力抵御外界农产品的竞争而处于市场萎缩和收入下降的状态。从理论上讲 ,农业是国民经济的基础 ,这决定了农业安全是经济安全的基础。农业是我们的衣食之源、生存之本 ;农业是工业原料的来源并为工业发展提供积累 ;农民的收入主要来源于农业并成为工业产品的重要购买力。农业出了问题 ,整个国民经济肯定会出问题。但是 ,随着经济的发展 ,特别是工业…     

劳动力转移与粮食安全

中国快速城市化和工业化导致的大量农村劳动力向城市转移引起了决策者和学术界对粮食安全问题的担忧,但本文利用县级和农户面板数据研究发现：首先,即使到2010年,农村劳动力转移对粮食总产量的影响并不大,对主产区的粮食总产量的影响更小,这背后的机制是主产区农户会通过更多地增加其他农业生产要素来替代劳动力投入的减少;其次,劳动力转移对主产区和非主产区农户的粮食生产行为的影响以及对主要粮食作物和次要粮食作物的影响都有所不同。总之,农村劳动力迁移尚未严重威胁到中国的粮食安全,当然,政府应针对粮食主产区和非主产区实施不同的政策以保持粮食总产量的稳定,特别是要鼓励主产区的耕地流转以降低劳动力迁移的负面影响。     

关于孙武的统计思想

关于孙武的统计思想胡不归孙武,字长卿,春秋末齐国人。生卒年月不详,约和孔丘（前５５１年—前４７９年）同时。他从齐国流亡到了吴国,受到吴王阖闾的重用,协助吴王经国治军。吴阖闾九年（前５０６年）,孙武随吴王率旅攻楚,指挥作战,五战五胜,以３万人破楚军２０...     

Block Design with Nested Rows and Columns for Research on Food Acceptability Limitation

Block designs with nested rows and columns were introduced in Srivastava (1978 Srivastava , J. N. ( 1978 ). Statistical design of agricultural experiments . J. Ind. Soc. Agric. Statist. 30 : 1 – 10 . [Google Scholar]) and more specifically defined in Singh and Dey (1979 Singh , M. , Dey , A. ( 1979 ). Block designs with nested rows and columns . Biometrika 66 ( 2 ): 321 – 326 .[Crossref], [Web of Science ®] , [Google Scholar]). We present properties of some partially balanced block designs with nested rows and columns. The designs are considered for near-factorial experiments, when there are a levels of experimental factor A and b levels of experimental factor B and there is one control treatment added. In this article we extend the theory of block designs with nested rows and columns described by \L acka and Koz?owska (2009 ?acka , A. , Koz?owska , M. ( 2009 ). Planning of factorial experiments in a block design with nested rows and columns for environmental research . Environmetrics 20 ( 6 ): 730 – 742 .[Crossref], [Web of Science ®] , [Google Scholar]) and Koz?owska et al. (2011 Koz?owska , M. , ?acka , A. , Krawczyk , R. , Koz?owski , R. J. ( 2011 ). Some block designs with nested rows and columns for research on pesticide dose limitation . Environmetrics 22 ( 6 ): 781 – 788 .[Crossref], [Web of Science ®] , [Google Scholar]). We carry out our consideration by the derived mixed linear model resulting from randomization of blocks, rows and columns. For this model of observations, some properties of estimation of treatment contrasts are discussed. We calculate the efficiency factors of estimation of treatment contrasts. We formulate theorems for some partially balanced block designs with nested rows and columns. Plant protection experiment on limitation of food acceptability for T. urticae is given to show how the obtained results can be applied.     

成人院校非统计专业统计学教学改革的思考

成人高等教育作为我国高等教育的重要组成部分,其各门学科的教学改革除了应遵循高等教育改革的一般规律与要求外,还应有自身的特殊规律与要求。本文通过对其特殊性的理性分析,提出成人非统计专业统计学教学应加强统计观念教育、统计法律与道德教育,并加强统计基本理论与方法的教学与改革。     

统计工作的经济学断想

统计工作是指统计人员利用科学的 方法搜集整理、分析和提供关于社会经济现象数量资料的工作,这项工作的意义就在于开发信息资源,发挥统计的信息、咨询和监督功能,为社会经济发展服务。     

Population,Food and Economic Adjustment

This article investigates the number of games of baseball that should be played (1) in a World Series competition, and (2) in a pennant race competition within each league, in order to have a reasonable level of confidence that the best team wins the competition. The current number of games played is found to be highly inadequate for the World Series and only barely sufficient for the pennant race.     

P-spline Estimation of Functional Classification Methods for Improving the Quality in the Food Industry

The aim of this article is to improve the quality of cookies production by classifying them as good or bad from the curves of resistance of dough observed during the kneading process. As the predictor variable is functional, functional classification methodologies such as functional logit regression and functional discriminant analysis are considered. A P-spline approximation of the sample curves is proposed to improve the classification ability of these models and to suitably estimate the relationship between the quality of cookies and the resistance of dough. Inference results on the functional parameters and related odds ratios are obtained using the asymptotic normality of the maximum likelihood estimators under the classical regularity conditions. Finally, the classification results are compared with alternative functional data analysis approaches such as componentwise classification on the logit regression model.     

变量选择方法及其在健康食品市场研究中的应用探究

数据挖掘是在大数据中提取客观规律的方法与艺术,如何准确与快速地提取合适的特征变量是其研究的关键问题之一。在模拟分析比较各种数据挖掘算法和提取变量效果的基础上,通过对健康食品市场进行实证研究,指出目前数据挖掘算法存在的不足及发展前景。     

农民食品消费结构分析

近几年,农民的饮食结构在调整中得到改善。然而,由目前温饱型的食品结构向小康型的食品结构过渡,面临着粮食与收入的双重制约。我们必须在允许的范围内寻找比较合理而又符合实际的食品消费模式,并作出审慎的选择。     

Variable Selection and Updating In Model-Based Discriminant Analysis for High Dimensional Data with Food Authenticity Applications

Food authenticity studies are concerned with determining if food samples have been correctly labelled or not. Discriminant analysis methods are an integral part of the methodology for food authentication. Motivated by food authenticity applications, a model-based discriminant analysis method that includes variable selection is presented. The discriminant analysis model is fitted in a semi-supervised manner using both labeled and unlabeled data. The method is shown to give excellent classification performance on several high-dimensional multiclass food authenticity datasets with more variables than observations. The variables selected by the proposed method provide information about which variables are meaningful for classification purposes. A headlong search strategy for variable selection is shown to be efficient in terms of computation and achieves excellent classification performance. In applications to several food authenticity datasets, our proposed method outperformed default implementations of Random Forests, AdaBoost, transductive SVMs and Bayesian Multinomial Regression by substantial margins.     

Food shelf life: estimation and optimal design

Shelf life is a specified percentile of the time-until-spoilage distribution of a food product. This paper investigates statistical properties of various estimators of shelf life and develops a genetic algorithm for finding near-optimal staggered designs for estimation of shelf life. MLEs and their associated confidence intervals for shelf life have smaller bias, better performance, and better coverage than the corresponding ad hoc regression-based estimates. However, performance of MLEs for common sample sizes must be evaluated by simulation. The genetic algorithm, coded as an SAS macro, searched the design space well and generated near-optimal designs as measured by improvement to a simulation-based performance measure.     

我国粮食生产的经济周期

一、我国粮食生产周期波动的成因(一)自然灾害对粮食生产的影响。40多年来,我国农业生产有了很大发展。但是,长期以来我国农业投资的比重和增幅不大,农业生产条件一直没有得到根本改善,加之原有设施老化,粮食生产抗御自然灾害的能力仍然十分脆弱。自然灾害一直是引发我国粮食生产周期波动的一个重要因素。(二)生产要素投入对粮食生产的制约。我国人均占有耕地少,农业生产的基础条件差,粮食生产一直受生产要素投入的制约。投入农业的人力、物力、财力和科技等生产要素的增减能直接引起粮食生产的波动。