Construction of disease risk scoring systems using logistic group lasso: application to porcine reproductive and respiratory syndrome survey data

We propose to utilize the group lasso algorithm for logistic regression to construct a risk scoring system for predicting disease in swine. This work is motivated by the need to develop a risk scoring system from survey data on risk factor for porcine reproductive and respiratory syndrome (PRRS), which is a major health, production and financial problem for swine producers in nearly every country. Group lasso provides an attractive solution to this research question because of its ability to achieve group variable selection and stabilize parameter estimates at the same time. We propose to choose the penalty parameter for group lasso through leave-one-out cross-validation, using the criterion of the area under the receiver operating characteristic curve. Survey data for 896 swine breeding herd sites in the USA and Canada completed between March 2005 and March 2009 are used to construct the risk scoring system for predicting PRRS outbreaks in swine. We show that our scoring system for PRRS significantly improves the current scoring system that is based on an expert opinion. We also show that our proposed scoring system is superior in terms of area under the curve to that developed using multiple logistic regression model selected based on variable significance.     

Measuring the impact of the Web: Rasch modelling for survey evaluation

In 2012, the World Wide Web Foundation launched for the first time the Web Index (WI), which combines the existing secondary data with new primary data to rank countries according to their progress and use of the Web. Primary data are gathered via a multi-country specifically designed questionnaire. The aim of our analysis is (1) to evaluate the measurement properties of the expert assessment survey and to provide survey designers with some insights into possible problematic questions and/or unexpectedly behaving countries and (2) to assess the experts’ perception of the state and the value of the Web. To do so the Rating Scale Rasch model is employed. Results show that about 10% of survey questions are detected as misfitting and need to be reworded. Possible reasons are: counter-orientation with respect to the WI polarity, difficulty in understanding the question's words or binary instead of the multiple response scale. Country analysis shows that no country can be considered as an outlier due to notable unexpected pattern of answers. Since the survey is to be expanded in future editions of the WI, the results of our analysis are very important in pin-pointing the questions most in need of refinement for the next edition of the Index.     

Comparison of Efficiency of Stratified and Unequal Probability Sampling

In this article, a choice of the optimum sampling design to study a finite population is studied. Three sampling schemes are compared, viz., Sunter's procedure of unequal probability sampling, stratified sampling under optimum stratification, and simple random sampling without replacement. The comparison is made against a background of various correlation between stratification and survey variables and various variability in the variables. Under weak correlation and large variability, stratification appeared to be more efficient than Sunter's procedure. Under strong correlation and/or low variability in the variables, the latter procedure was the most efficient. Simple random sampling was usually the least efficient.     

猴矶岛海域潮流监测及对潮流能发电示范工程的作用

本文依据2013年7月对长岛县猴矶岛附近海域开展的周日海流连续调查观测,分析了猴矶岛潮流能分布的特点,为长岛县猴矶岛潮流能利用示范工程建设提供了依据.项目建设可为我国偏远海岛潮流能电力系统的建设起到示范作用,为偏远海岛的经济开发提供技术支持.     

城市中心区货运需求调查研究——以北京为例

面对城市交通拥堵日趋严重的形势,城市货运发展关乎经济保障。目前我国城市交通规划及研究重心在客运,货运调查由于难度大开展不多,货运交通设施规划建设和相关政策制定成为城市交通薄弱环节。通过北京市中心区货运需求调查实践,系统介绍调查内容、调查方法、抽样方法等方面的特点,从货运量、货运车次、货运空间及时间分布等方面介绍调查结果,并总结组织模式、工作流程以及抽样框建立等方面的做法,为其它城市开展货运调查提供经验借鉴。     

KUK随机化调查模型下的贝叶斯估计

本文针对属性特征的KUK模型建立了贝叶斯估计理论,求出了在先验分布是混合贝塔先验分布、抽样方法是简单随机抽样情况下总体敏感特征比例的贝叶斯估计,并且使用后验均方误差作为精度标准,对贝叶斯估计与极大似然估计进行比较。     

近二十年文言梦幻小说及相关研究综述

文言梦幻小说是中国古代文言小说重要的组成部分。近二十年来,许多梦幻小说研究论文在继承传 统研究方式的基础上,不断吸收新的研究成果,从不同侧面、不同角度、不同立场提出了许多新见解、新观点,为古 代文言梦幻小说的研究拓宽了道路。从文言梦幻小说源头研究、发展研究、文化研究、版本考据研究、艺术理论研 究以及相关专著研究等方面略作总结,可使我们对此课题有一整体性了解,对文言梦幻小说的发展现状有一总体 性把握。     

新中国五十年湖南中篇小说巡礼

新中国50年特别是新时期以来的湖南中篇小说,名篇佳构联袂而出,令人目不暇接,文苑震惊,有口皆碑,堪称湖南文学的代表。     

大学英语教学应重视学生学习风格的个体差异

运用学习风格测量表对学习者个体差异研究领域中大学生英语学习风格进行测量,并针对三种具有不同风格的学习者:视觉型学习者、听觉型学习者、触觉型学习者提供了具体可操作的学习策略,同时为大学英语教师提供了相应的教学策略.     

Gender and Illicit Drug Use

Correspondence to Dr Joanne Neale, Department of Social Policy and Social Work, University of York, Heslington, York Y010 5DD, UK. E-mail: jsn3{at}york.ac.uk Summary There has been no recent large-scale systematic UK investigationof differences between male and female drug users seeking treatment.Equally, there has been no debate within the social work fieldregarding how best to address any gender-specific needs of drug-usingclients. This is despite the fact that social workers frequentlywork with both drug-dependent individuals and members of theirfamilies. This paper examines differences between men and womenbeginning a new episode of drug treatment in Scotland and considerssome of the implications of the findings for social work practice.Data were collected from structured interviews conducted with1,033 individuals (715 males and 318 females) in a range oftreatment settings. Chi-square statistics were computed to investigatesex differences on key categorical variables relating to: (i)patterns of drug use; (ii) education, employment and income;(iii) offending behaviour; (iv) housing circumstances; (v) healthstatus; and (vi) personal relationships. Analyses identifiedmany differences between the men and women interviewed, butalso many common difficulties faced by respondents of both sexes.Additionally, the extensive range of problems and stressfullife circumstances encountered suggested that the lives of individualsseeking drug treatment were extremely heterogeneous. It is concludedthat social workers can employ a range of practical interventionsand theoretical approaches when working with both male and femaledrug-using clients.