C/C 程序设计中指针的运用

面向过程的C语言和面向对象的C 语言中都引入了指针的概念。指针是C/C 中特性较强、功能较好的应用之一。然而指针也是C/C 中最不容易理解和掌握的概念。本文针对C/C 中的指针原理及使用方法做了较为系统的论述,并对其应用进行了系统的归类,对每一种应用都用实例加以阐述,为学习C/C 指针的相关知识提供了快捷有效的方法。     

云南省城乡居民消费差异的Panel Data模型

采用包含信息充分的面板数据(Panel Data)建立变系数和变截距模型对1993~2004年的云南省城乡消费的样本数据进行了分析,得出结论:样本期间云南省城乡居民的消费性支出差距小于收入差距。认为分析城乡差距时,如果直接采用收入比较就会夸大差距的水平而导致负面影响加强,不利于社会的稳定,应该考虑农村居民收入中的非货币化部分。采用城乡居民的消费性支出来测量这两个群体的差距,这样更具有客观性和合理性;云南省城乡消费存在着显著差异,具体为食品、家庭设备、医疗保健和文教娱乐的平均消费水平差异以及衣着、居住、交通通讯的边际消费倾向差异;城镇和农村居民新增消费支出排在前三位的分别为“食品—交通通讯—文教娱乐”和“食品—居住—文教娱乐”;城乡消费差距有扩大化趋势。认为这一切都是因为农民增收太慢造成的,对此提出具体的提高农民收入的措施。     

The distribution of random determinants

The exact distribution of |Δn| where Δn is a random determinant with independent and identically distributed exponential elements is given for the cases n = 2 and 3. From the investigation of the behaviour of the density functions for these cases it is conjectured that for any fixed n, the probability density of |Δn| for large values of the argument is the same as the density of (Y/n)ⁿ, where Y is a gamma random variable.     

服务贸易限制、制度质量与国家经济增长

服务贸易作为2008年全球金融危机后拉动世界贸易增长的新引擎,对一国经济增长有着重要影响。在梳理相关理论和文献的基础上,基于2004—2017年80个国家的跨国面板数据,实证分析了服务贸易限制对经济增长的影响,并进一步探究了制度质量的调节作用。研究发现,服务贸易限制会阻碍经济增长,高质量的政治制度和经济制度能够有效缓解其阻碍作用。从国别异质性角度来看,服务贸易限制对不同收入水平国家经济增长的影响存在差异,其中对高收入国家经济增长的消极影响最大,其次是中高等收入国家和中低等收入国家,最后是低收入国家;政治制度质量和经济制度质量对不同收入水平的国家均具有正向调节作用。从行业异质性视角来看,专业服务贸易限制对经济增长的消极影响最大,其次是运输服务和通信服务,最后是金融服务;无论是政治制度质量还是经济制度质量对不同行业均具有正向调节作用。从服务贸易供应模式异质性角度来看,跨境交付模式的限制对经济增长的消极影响大于商业存在及自然人流动模式,且制度质量具有弱化的调节作用。研究结果表明,放宽服务贸易限制,完善制度建设,推进国家治理体系和治理能力现代化,均有助于促进国家经济增长。     

Beyond Munchausen by Proxy: A Proposed Conceptualization for Cases of Recurring,Unsubstantiated Sexual Abuse Allegations

In the emerging literature, cases involving recurring, unsubstantiated allegations of child sexual abuse have generally been categorized as Munchausen by proxy. Recent scholars have recommended restricting the label to the original conceptualization, involving purposeful deception motivated by psychological needs for medical attention. This leaves many cases unclassified that do not fit the Munchausen by proxy criteria, involve significant risks to the child, and ultimately fall outside of existing structures for Child Protective Services/legal intervention. This paper presents a reconceptualization of such cases, proposing to label them “recurring sexual abuse allegation” cases. Defining the set of cases more clearly can aid child protection workers in their management and encourage research on prevalence, consequences to children, treatment strategies, and needed legal reforms.     

Revisiting ethnography by proxy

Abstract

Prompted by discovering a paper written in 1980 which described a process of ‘ethnography by proxy’, I revisit this concept in the light of two research projects: a workplace study of an electronics company conducted in the early 1990s and a later home-based study of young children’s encounters with toys and technology. The paper defines ethnography by proxy as the process of delegating some of the ethnographer’s activities to participants in the research setting. It discusses a pragmatic response to some of the challenges of conducting fieldwork and considers the implications of delegating non-academic proxies to fulfil aspects of the ethnographer’s role, the different guises that may be taken by the ethnographer and what this shift in research relationships might mean for the interpretation of data. The concept of proxy has implications for some of the tenets of ethnographic research as it requires a re-examination of our roles and the relationship between researcher and researched.     

倒立摆滑模变结构控制器的设计与实现

倒立摆是检验控制算法性能优劣的理想装置,滑模变结构控制策略以其滑动模态的完全鲁棒性而备受关注。本文以天龙I型倒立摆为控制对象,研究对其实现有效控制的滑模变结构控制策略。首先建立了倒立摆的数学模型;其次根据模型特点设计了滑模变结构控制器,最后通过仿真和实物控制两种手段,验证了所论控制策略的正确性和可行性。     

Trade openness and income inequality: New empirical evidence

We examine how trade openness influences income inequality within countries. The sample includes 139 countries over the period 1970–2014. We employ predicted openness as instrument to deal with the endogeneity of trade openness. The effect of trade openness on income inequality differs across countries. Trade openness tends to disproportionately benefit the relative income shares of the very poor, but not necessarily all poor, in emerging and developing economies. In most advanced economies, trade openness increased income inequality, an effect that is driven by outliers. Our results suggest a strong effect of trade openness on inequality in China and transition countries.     

Hidden Markov model for discrete circular–linear wind data time series

ABSTRACT

In this work, we deal with a bivariate time series of wind speed and direction. Our observed data have peculiar features, such as informative missing values, non-reliable measures under a specific condition and interval-censored data, that we take into account in the model specification. We analyse the time series with a non-parametric Bayesian hidden Markov model, introducing a new emission distribution, suitable to model our data, based on the invariant wrapped Poisson, the Poisson and the hurdle density. The model is estimated on simulated datasets and on the real data example that motivated this work.