会话交际中的语码转换研究--以某校英语专业学生宿舍会话交际为例

通过对某高校英语专业10个宿舍日常会话交际中的会话实例进行观察和记录,并依据会话实例对英语专业学生宿舍交际中语码转换的类型、特征、发生原因、功能及影响因素进行全面分析和研究,进而提出可行性建议,以克服学生在学习英语的过程中进行语码转换时的影响因素。     

中国通货膨胀率的非线性动态行为研究——来自MS—ARFIMA模型的新证据

使用允许长记忆参数d服从区制转换的MS—ARFIMA模型对中国月度通货膨胀路径的动态行为进行新的实证研究,结果显示：中国通货膨胀不仅均值水平和不确定性存在着“低通胀”区制和“高通胀”区制,而且更为重要的是,通货膨胀序列的平稳性也表现出显著的区制转换动态。“低通胀”区制下,长记忆参数d1=0．361,说明通货膨胀是协方差平稳序列,“高通胀”区制下,长记忆参数d2=1．145,说明通货膨胀是非平稳序列。这一新的研究结论意味着中国通货膨胀冲击的持久性效应也存在相应的区制转移变化。这要求央行在管控通货膨胀过程中,既要考虑均值和不确定性的区制变化,又要兼顾平稳性和持久性的区制变化。     

A Markov regime‐switching model for crude‐oil markets: Comparison of composite likelihood and full likelihood

We use the two‐state Markov regime‐switching model to explain the behaviour of the WTI crude‐oil spot prices from January 1986 to February 2012. We investigated the use of methods based on the composite likelihood and the full likelihood. We found that the composite‐likelihood approach can better capture the general structural changes in world oil prices. The two‐state Markov regime‐switching model based on the composite‐likelihood approach closely depicts the cycles of the two postulated states: fall and rise. These two states persist for on average 8 and 15 months, which matches the observed cycles during the period. According to the fitted model, drops in oil prices are more volatile than rises. We believe that this information can be useful for financial officers working in related areas. The model based on the full‐likelihood approach was less satisfactory. We attribute its failure to the fact that the two‐state Markov regime‐switching model is too rigid and overly simplistic. In comparison, the composite likelihood requires only that the model correctly specifies the joint distribution of two adjacent price changes. Thus, model violations in other areas do not invalidate the results. The Canadian Journal of Statistics 41: 353–367; 2013 © 2013 Statistical Society of Canada     

医疗信息共享对患者转移数量和服务质量水平影响研究

当前我国医院间存在严重的"信息孤岛"，医院参与医疗信息共享意愿不高，患者的诊疗信息被静态碎片化储存而无法充分有效地利用。考虑到医院进行医疗信息共享将降低患者转移成本，本文构建一个多阶段双寡头动态博弈模型研究医疗信息共享对医院竞争过程中患者转移数量和服务质量水平决策的影响。首先，根据是否存在转移成本，将患者分为新患者和经验性患者，借助Hotelling模型刻画患者的效用函数，分析患者就诊决策。然后，在政府价格规制和不考虑医院利他性情景下，构建了医院累积期望收益目标函数，使用动态规划方法，求解实现医院累积期望收益最大化的服务质量水平，获得了实现患者相互转移且医院在市场中共存的马尔可夫完美均衡。最后，根据医院参与医疗信息共享后患者转移成本降为零，分析与比较信息共享前后患者转移数量和服务质量水平变化。研究发现：在不同医院间本身存在患者转移背景下，医院参与信息共享后，患者转移数量增加但存在一个上限，增加的转移量与患者在医院间的转移成本呈正相关，与初始感知效用的差值范围呈负相关；医院参与信息共享后，均衡状态下的医院服务质量水平高于信息共享前的服务质量水平。因此，在不改变当前医保支付方式下，要加快推进医疗信息共享，政府部门可以根据医院的患者数量和服务质量水平变化对其进行定期补贴，以激励医院积极参与医疗信息共享，本文给出了这个补贴的量化表达。     

Social relationships and shifting languages in Northern Thailand1

This paper explores how speakers’ understandings of the conduct of social relationships mediate changing and socially distinctive syncretic language practices in a Northern Thai community. Although a shift away from vernacular (Kam Muang) speech styles to Standard Thai was emblematically tied to young and urban speakers in nostalgic discourses, syncretic speech styles and metalinguistic discourses also reflected local and socially positioned understandings of institutional roles and social relationships. I argue that scholars of language change and shift should foreground the mediating role of social relationships in speakers’ uses and understandings of their communicative repertoires across multiple timescales.     

快速分层切换移动IPv6协议技术性能的分析和比较

随着互联网和无线移动通信技术的快速发展,越来越多的用户使用移动终端接入互联网,无线移动接入技术与IPv6结合起来成为目前的研究热点。通过分析基于移动IPv6协议的分层切换技术,比较其技术之间的性能,结合实际应用价值,给出了分析比较的结论。     

Relabelling algorithms for mixture models with applications for large data sets

Mixture models are flexible tools in density estimation and classification problems. Bayesian estimation of such models typically relies on sampling from the posterior distribution using Markov chain Monte Carlo. Label switching arises because the posterior is invariant to permutations of the component parameters. Methods for dealing with label switching have been studied fairly extensively in the literature, with the most popular approaches being those based on loss functions. However, many of these algorithms turn out to be too slow in practice, and can be infeasible as the size and/or dimension of the data grow. We propose a new, computationally efficient algorithm based on a loss function interpretation, and show that it can scale up well in large data set scenarios. Then, we review earlier solutions which can scale up well for large data set, and compare their performances on simulated and real data sets. We conclude with some discussions and recommendations of all the methods studied.     

Construction and selection of tightened–normal–tightened variables sampling scheme of type TNTVSS (n 1, n 2; k)

This paper provides tables for the construction and selection of tightened–normal–tightened variables sampling scheme of type TNTVSS (n ₁, n ₂; k). The method of designing the scheme indexed by (AQL, α) and (LQL, β) is indicated. The TNTVSS (n _T , n _N; k) is compared with conventional single sampling plans for variables and with TNT (n ₁, n ₂; c) scheme for attributes, and it is shown that the TNTVSS is more efficient.     

语言态度对普通话与陕西话语码转换的影响研究

本课题通过问卷调查、实地访谈等方法,从社会语言学的视角,探讨西安地区人们的语言态度对普通话与陕西话语码转换的影响。试图解读陕西方言文化自信与官方语言推广之间的矛盾与和谐。研究发现,人们对于这两种语言变体的态度中既包含了对语言交际功能的认知因素,也包含了情感因素,因此,在大力推广普通话的同时,不可忽视西安人对其地域方言的认同感与文化自豪感。     

基于MSVAR模型的有色金属价格波动影响因素的非线性效应研究

由于新兴市场需求增长和指数化投资同时出现在金属期货市场上,且供需因素与金融因素相互作用使得有色金属价格形成机制更为复杂,呈现出非线性、动态性以及结构异化等特征。基于此背景,本文提炼供需因素与金融因素影响有色金属价格波动的作用机理,选取2000年2月至2014年3月的月度数据,并构建MSVAR模型以铜为例展开实证分析。结果表明:铜价波动存在显著的区制转换特征,即膨胀期、平稳期、低迷期三种状态;三种状态下,金融因素都可以很好地解释期铜价格波动,但作用机制明显不同,而"中国因素"则被明显夸大,与原有研究结论相左;短期内各个因素在不同区制下对国际期铜价格的影响在作用方向、持续时间、作用强度上表现出显著的差异性。这些研究结论与构建的非线性计量经济模型为解释大宗商品金融化提供了新的思路与分析工具。