An EWMA chart for monitoring process mean

In the statistical process control literature, there exists several improved quality control charts based on cost-effective sampling schemes, including the ranked set sampling (RSS) and median RSS (MRSS). A generalized cost-effective RSS scheme has been recently introduced for efficiently estimating the population mean, namely varied L RSS (VLRSS). In this article, we propose a new exponentially weighted moving average (EWMA) control chart for monitoring the process mean using VLRSS, named the EWMA-VLRSS chart, under both perfect and imperfect rankings. The EWMA-VLRSS chart encompasses the existing EWMA charts based on RSS and MRSS (named the EWMA-RSS and EWMA-MRSS charts). We use extensive Monte Carlo simulations to compute the run length characteristics of the EWMA-VLRSS chart. The proposed chart is then compared with the existing EWMA charts. It is found that, with either perfect or imperfect rankings, the EWMA-VLRSS chart is more sensitive than the EWMA-RSS and EWMA-MRSS charts in detecting small to large shifts in the process mean. A real dataset is also used to explain the working of the EWMA-VLRSS chart.     

A new algorithm for clustering based on kernel density estimation

In this paper, we present an algorithm for clustering based on univariate kernel density estimation, named ClusterKDE. It consists of an iterative procedure that in each step a new cluster is obtained by minimizing a smooth kernel function. Although in our applications we have used the univariate Gaussian kernel, any smooth kernel function can be used. The proposed algorithm has the advantage of not requiring a priori the number of cluster. Furthermore, the ClusterKDE algorithm is very simple, easy to implement, well-defined and stops in a finite number of steps, namely, it always converges independently of the initial point. We also illustrate our findings by numerical experiments which are obtained when our algorithm is implemented in the software Matlab and applied to practical applications. The results indicate that the ClusterKDE algorithm is competitive and fast when compared with the well-known Clusterdata and K-means algorithms, used by Matlab to clustering data.     

Spatially Balanced Sampling of Continuous Populations

When sampling from a continuous population (or distribution), we often want a rather small sample due to some cost attached to processing the sample or to collecting information in the field. Moreover, a probability sample that allows for design‐based statistical inference is often desired. Given these requirements, we want to reduce the sampling variance of the Horvitz–Thompson estimator as much as possible. To achieve this, we introduce different approaches to using the local pivotal method for selecting well‐spread samples from multidimensional continuous populations. The results of a simulation study clearly indicate that we succeed in selecting spatially balanced samples and improve the efficiency of the Horvitz–Thompson estimator.     

A robust automatic clustering algorithm for probability density functions with application to categorizing color images

This study develops a robust automatic algorithm for clustering probability density functions based on the previous research. Unlike other existing methods that often pre-determine the number of clusters, this method can self-organize data groups based on the original data structure. The proposed clustering method is also robust in regards to noise. Three examples of synthetic data and a real-world COREL dataset are utilized to illustrate the accurateness and effectiveness of the proposed approach.     

Several least-squares problems related to the Hodrick–Prescott filtering

The Hodrick–Prescott (HP) filtering is frequently used in macroeconometrics to decompose time series, such as real gross domestic product, into their trend and cyclical components. Because the HP filtering is a basic econometric tool, it is necessary to have a precise understanding of the nature of it. This article contributes to the literature by listing several (penalized) least-squares problems that are related to the HP filtering, three of which are newly introduced in the article, and showing their properties. We also remark on their generalization.     

Political and economic determinants of expenditure on day services for persons with intellectual disabilities or autism

This study investigates whether the Swedish national entitlement legislation, which is known to be one of the most developed in Europe for persons with intellectual disabilities or autism, accomplishes its aim to provide equal quality of day services independent of location. We estimated a reduced-form model of demand and supply-side determinants of a latent quality variable for day-service programmes using panel data on expenditure per attendee for the 290 Swedish municipalities 2004–2012. We found that expenditure per attendee is among others affected by changes of the local tax base and outcome in elections to the local assemblies. These results imply that rights of persons with intellectual disabilities with regard to equal quality of day services independent of where they live are not fully honoured in budget allocation decisions made by local governments.     

Controlling the illusion of control: a grounded theory of sports betting advertising in the UK

Sports betting advertising has arguably permeated contemporary sport consumption in many countries. Advertisements build narratives that represent situations and characters that normalize betting behaviour and raise public concerns regarding their detrimental effect on vulnerable groups. Adopting a grounded theory approach, the present study examined a British sample of sports betting advertisements (N = 102) from 2014 to 2016. The analysis revealed that individual themes aligned in a single core narrative, constructing a dual persuasive strategy of sports betting advertising: (i) to reduce the perceived risk involved in betting (with themes such as betting with friends, free money offers, humour, or the use of celebrities) while (ii) enhancing the perceived control of bettors (including themes of masculinity and sport knowledge). In addition, new technological features of sports betting platforms (e.g. live in-play betting) were used by advertisers to build narratives in which the ability to predict a sports outcome was overlapped by the ability of bettors to use such platforms, equalizing the ease of betting with the ease of winning. Based on the data analysed, it was concluded that the construction of a magnified idea of control in sports betting advertising is a cause for concern that requires close regulatory scrutiny.     

Impact of technology-intensive exports on GDP of Western Balkan Countries

This paper aims to determine, by means of regression analysis, which exported product groups, categorized according to their technological intensity, have the greatest effect on the movements in the volume of GDP p/c of the Western Balkan Countries (WBCs). The analysis, based on statistical-econometric methodology, includes 16 commodity groups per each WBC (Albania; Bosnia and Herzegovina; Croatia; FYR Macedonia; Montenegro; Serbia). The data were collected and presented in accordance with the HS4 system classification, which is also used for development of the ITC’s Trade Map. The results of the analysis show that those commodity groups produced by medium-low and low technology industries have the greatest effect on the change in the volume of GDP p/c in all WBCs in the period 2005–2015.     

电子商务平台吸附能力的影响机制研究———平台柔性和控制机制的交互效应

平台型电子商务已经成为未来经济发展的主要推动力,如何构建并应用这种平台商务模式已经成为企业管理者普遍关心的问题.然而现有文献对电子商务平台的研究还比较少,主要基于平台主体的案例研究,缺乏从平台商家角度对如何形成电子商务平台的吸附力并激发网络效应的实证检验.基于模块系统理论和控制机制的相关文献,提出了平台柔性、平台控制、以及二者交互作用对平台吸附能力的影响模型.通过对185家平台参与企业的实证研究,研究结果显示平台柔性、正式控制、和关系控制均显著影响电子商务平台吸附能力;另外,平台柔性和正式控制对电子商务平台吸附能力的形成存在替代效应,平台柔性和关系控制对电子商务平台吸附能力的形成存在互补效应,正式控制和关系控制对电子商务平台吸附能力也存在互补效应.研究发现,对于模块系统理论和控制机制的应用情景进行了扩展和延伸,也为电子商务平台的管理者提供了有益的建议.     

“GPS测量与数据处理”课程教学与改革

卫星导航定位是测绘工程中发展较快、应用较广的一项热门技术,“GPS测量与数据处理”课程也一直是测绘专业本科教学的主干课程,具有更新快、理论深、实践性强等特点,对教师授课及学生学习都具有较高的要求。文章对东华理工大学测绘工程专业GPS课程的授课内容、授课方式、实践教学及考核模式等方面存在的问题进行了分析,并提出了相应的教学改革建议。