Explicit analytical solutions for ARL of CUSUM chart for a long-memory SARFIMA model

This paper aims to derive explicit analytical solutions for Average Run Length (ARL) of CUSUM chart for the SARFIMA(P,D,Q)_S process with exponential white noise. Measurement of performance was done with the ARL in terms of percentage error and CPU time. The results obtained from the explicit formulas were compared focusing on the performance using the numerical integral equation (NIE) method. Both methods had similarly excellent agreement with the percentage error at less than 0.25%. Meanwhile, the explicit formulas consumed less CPU time than the NIE method. It is clear that the explicit formulas are a good alternative in real applications.     

语言象似性视角下的翻译研究——以杨宪益、戴乃迭英译《阿Q正传》为例

从篇章象似性的视角出发,考察杨宪益、戴乃迭翻译的《阿Q正传》英译本中两类对称象似性——重复和排比的处理方法。通过对比分析,品评不同处理方式的得失,指出翻译过程中应做到形式对等,尽可能地再现原文中具有表现意义的象似性,以实现译文与原文“形神皆似”。     

基于FPGA的高频等精度频率计设计与实现

文章介绍了等精度频率计误差分析和实现原理,在Altera新一代FPGA/PLD开发软件QuartusⅡ 中运用硬件描述语言Verilog HDL编程,通过单片机控制EP1 C12Q240I7芯片实现等精度频率计的设计,频率计可通过分频测量800 MHZ～1 400 MHZ之间的高频信号频率,大大提高了测量精度,实验证明测量精度为0.000 03％以下.     

The relationship between conflict events and commodity prices in Sudan

Though recent literature uncovers linkages between commodity prices and conflict, the causal direction of the relationship remains ambiguous. We attempt to contribute to this strand of research by studying the dynamic relationship of commodity prices and the onsets of conflict events in Sudan. Using monthly data ranging from January 2001 through December 2012, we identify a structural breakpoint in the multivariate time series model of prices of the three staple foods (sorghum, millet, and wheat) and conflict measure (number of conflict events) in September of 2011. Applying structural vector autoregression (SVAR) and linear non-Gaussian acyclic model (LiNGAM), we find that wheat price fluctuation is a root cause of conflict events in Sudan. We recommend several policy and programmatic suggestions structured toward production, subsidy, price regulation and support for rural farmers and consumers to stabilize commodity prices.     

China's energy inefficiency: A cross-country comparison

This paper constructs a total-factor energy technical efficiency index using the data envelopment analysis (DEA) method following the total factor productivity framework. We then compare energy technical efficiency across 156 countries from 1980 to 2007. The results show that China's energy efficiency considerably trails other countries’ although it has made significant gains within the last 28 years. Further analysis indicates that scale inefficiency rather than pure technical efficiency contributes to China's energy inefficiency.     

Nonparametric modelling of biodiversity: Determinants of threatened species

This study uses a sample of 71 countries and nonparametric quantile and partial regressions to model a number of threatened species (reptiles, mammals, fish, birds, trees, plants) in relation to various economic and environmental variables (GDPc, CO₂ emissions, agricultural production, energy intensity, protected areas, population and income inequality). From the analysis and due to high asymmetric distribution of the dependent variables it seems that a linear regression is not adequate and cannot capture properly the dimension of the threatened species. We find that using OLS instead of non-parametric techniques over- or under-estimates the parameters which may have serious policy implications.     

Q methodology in social work research

This article examines Q methodology as an empirical method for use in social work research. Q methodology applies statistical analysis to the qualitative study of human subjectivity such as attitudes, beliefs, feelings and opinions. Q methodology is effective for obtaining data from small samples, and it offers respondents a concise and valid way of expressing their viewpoints with minimal researcher interference. The article provides an overview of Q methodology and presents an actual example of a small‐scale Q study to facilitate a better understanding of the method. We conclude that Q methodology is especially suitable in social work research with respondents who may have difficulties in expressing themselves when more conventional research methods are used. Q methodology is an efficient tool in research involving the exploration and comparison of different points of view.     

Return and volatility interaction between oil prices and stock markets in Saudi Arabia

The paper aims at investigating the links between world oil price and stock sector markets in Saudi Arabia over the weekly period from January 10, 2007 until September 28, 2011. To that effect, we make use of the VAR-GARCH process developed by Ling and McAleer (2003), which has the advantage to address the issue of return and volatility spillovers among the series we consider. Globally, the empirical findings show evidence of return and volatility transmission between oil price and stock sectors. However, the spillover effects are unidirectional from oil to some sectors for returns, but bidirectional for volatility patterns with more apparent links from sectors to oil. The optimal weights and hedge ratios for oil/stock portfolio holdings are sensitive to the sectors considered, and allow a better understanding of the links between sectors and oil for investors who seek for investment opportunities and want to diversify their portfolios. The findings are of great interest and have important implications for investors, market participants and policy makers.     

And yet they Co-move! Public capital and productivity in OECD

In this paper, we add to the debate on the public capital–productivity link by applying very recent developments in the panel time series literature that take into account cross sectional correlation in non-stationary panels. In particular, we evaluate the productive effect of public capital by estimating various production functions on a panel of 21 OECD countries over the period 1975–2002. Our results suggest that public capital has a positive long run impact on output, with elasticities that range between 0.05 and 0.15, depending on model specification. These findings are robust to the existence of spillover effects from public capital investments in other countries and to the inclusion of other productivity determinants, like human capital, the stock of patents and R&D capital. Finally, we do not find any important effect of public capital on GDP in the short run: this suggests that public infrastructure investments might not be a powerful countercyclical policy instrument.