Bounded influence estimation for regression and scale

Bednarski and Müller [Optimal bounded influence regression and scale M-estimators in the context of experimental design, Statistics 35 (2001), pp. 349–369] introduced a class of bounded influence M estimates for the simultaneous estimation of regression and scale in the linear model with normal errors by solving the corresponding normal location and scale problem at each design point. This limits the proposal to regressor distributions with finite support. Based on their approach, we propose a slightly extended class of M estimates that is not restricted to finite support and is numerically easier to handle. Moreover, we employ the even more general class of asymptotically linear (AL) estimators which, in addition, is not restricted to normal errors. The superiority of AL estimates is demonstrated by numerical comparisons of the maximum asymptotic mean-squared error over infinitesimal contamination neighbourhoods.     

Coping with Vulnerabilities in Old Age and Retirement: Cross-border Mobility,Family Relations and Social Networks of German Retirees in Alanya

ABSTRACT

Reduced income upon retirement is a vulnerability threat, which increases dependency on public provisions, familial, and/or social (community) support. Many German retirees, in addition to lifestyle motivations, move to low-cost destinations in order to maintain an autonomous and independent life while minimizing the risks of financial worsening. In this article, I discuss the vulnerability patterns of German retirees in the Mediterranean coastal town of Alanya, Turkey, and the role of social networks, with a particular focus on intergenerational family relations. I argue that, despite increased life satisfaction, relocation to a new destination abroad results in new emerging threats. German retirees in Alanya experience difficulties in terms of a lack of intergenerational family support and the double jeopardy of being framed by the legal regulations of two nation states. Based on the findings of the empirical research conducted in Alanya in 2017, I will demonstrate new threats emerged after relocation and how retirees respond to those with new coping strategies.     

‘When and where does being Welsh matter to me?’ The influence of cross-border mobilities on constructions of sub-national belonging in the lives of Welsh Muslims*

This article will discuss how Welsh Muslims construct what a sense of place means to them through their cross-border mobility between England and Wales, and how this contributes to the ongoing re-construction of a plural understanding of nationhood in an era of diversity. To understand when and where being Welsh matters to Welsh Muslims, it will explore how mobility rather than being the antithesis of belonging, can be used as an essential tool in highlighting how perceptions of the nation, sub-state nation, home and place are influenced and understood.     

边疆地区流动人口基本特征及居留意愿

利用2014年云南省和内蒙古自治区流动人口动态监测数据,基于STATA统计软件平台运用二元logistic回归分析发现:边疆地区流动人口居留意愿的影响因素存在明显的区域差异,主要表现在年龄、户口性质、婚姻状况、职业种类和住房性质5个方面。但也存在一些共性的因素,即流动范围、在流入地的工作区域、流入地的家庭月收入和流入时间长短都会显著影响流动人口的居留意愿。边疆地区的人口流动范围以省内为主,近距离的人口迁移流动加剧了流动人口家庭化趋势。实际上,边疆地区流动人口也处于"留"而不"流"的稳定状态,在流入地平均居留时间在6年以上。     

论洛杉矶文学先锋创作：詹姆斯·凯恩和 霍勒斯·麦科伊

凯恩和麦科伊被称作洛杉矶文学开拓先锋,他们的创作存在许多相似之处。首先,他们有着相似的城市经历。其次,他们作品中的主人公都没有归属感,都是无根之人。 他们背离自己的生命之源土地,被蛊惑来到这片精神贫瘠之地寻找希望和梦想。在这片梦幻的空间,人类基本的关系遭受了巨大的冲击以致最终崩溃。这两位作家赋予洛杉矶一种 全新的文学身份。     

第五次跨国并购浪潮的特点及动因分析

第五次跨国并购浪潮呈现出并购金额巨大、增长速度迅猛、发达国家在并购出售额和购买额中居主导地位、以水平及善意并购方式为主要特点。推动其形成和发展的动因,既有经济全球化、新科技革命发展等宏观原因,也有谋求经营协同、财务协同、获取并购战略价值、操纵市场等微观原因。面对此浪潮,我国应积极更新观念,加强立法,改善环境;以顺应并利用跨国并购为我国经济结构调整和经济发展服务。     

INSIGHTS ON SERVICE SYSTEM DESIGN FROM A NORMAL APPROXIMATION TO ERLANG'S DELAY FORMULA

We show how a simple normal approximation to Erlang's delay formula can be used to analyze capacity and staffing problems in service systems that can be modeled as M/M/s queues. The numbers of servers, s, needed in an M/M/s queueing system to assure a probability of delay of, at most, p can be well approximated by s ≅ p + z_***I-p+, where z_1-p, is the (1 - p)th percentile of the standard normal distribution and ρ, the presented load on the system, is the ratio of Λ, the customer arrival rate, to μ, the service rate. We examine the accuracy of this approximation over a set of parameters typical of service operations ranging from police patrol, through telemarketing to automatic teller machines, and we demonstrate that it tends to slightly underestimate the number of servers actually needed to hit the delay probability target—adding one server to the number suggested by the above formula typically gives the exact result. More importantly, the structure of the approximation promotes operational insight by explicitly linking the number of servers with server utilization and the customer service level. Using a scenario based on an actual teleservicing operation, we show how operations managers and designers can quickly obtain insights about the trade-offs between system size, system utilization and customer service. We argue that this little used approach deserves a prominent role in the operations analyst's and operations manager's toolbags.     

The influence of tax authorities on the employment of tax practitioners: Empirical evidence from a survey and interview study

Tax practitioners play a crucial role in the degree of taxpayers’ compliance – a role that has increased as tax systems worldwide have become more complex. However, little is known about tax authorities’ impact on taxpayers’ decisions to employ tax practitioners. Based on earlier research on motivations to employ a tax practitioner and the extended slippery slope framework of tax compliance, we conducted two studies which provide some answers. A survey study – comprising a representative sample of 500 Austrian self-employed taxpayers – revealed that financial gain is not the most important reason to employ a tax practitioner but instead the motivation to avoid problems with the tax authorities. Related to that, we also find that taxpayers’ perception of tax authorities wielding coercive power motivates them to employ tax practitioners. In the interview study with 33 self-employed taxpayers and 30 tax auditors, taxpayers indicated that they sought to avoid contact with tax officers by employing tax practitioners. This finding was supported by tax officers who reported preferring interaction with tax practitioners over direct contact with taxpayers. The two studies point to the complex relationship between taxpayers, tax authorities and tax practitioners, and allow the drawing of theoretical and practical implications.     

论产业跨界融合对服务经济的影响

产业跨界融合是生产力进步以及产业结构高级化的必要条件,它给上海新一轮发展提出了诸多挑战,同时也赋予其极大的发展机遇。服务业发展,既需要先进制造业、现代服务业的融合发展,也要推动服务行业间的融合发展,增强服务业自主增长能力。然而,上海目前还存在诸多制约产业扩散和融合的障碍性因素。透彻了解产业跨界融合的涵义、具体形式及其影响,设计符合产业跨界融合规律和发展趋势的规制框架,从优化产业融合的内外部环境入手,制定和实施新的政策、措施,来保障和促进产业融合这一新型产业创新的顺利发展,是上海经济与社会发展的客观需求,也是理论界和决策部门亟待解决的关键问题。