Characterizing time series : when Granger causality triggers complex networks

In this paper, we propose a new approach to characterize time series with noise perturbations in both the time and frequency domains by combining Granger causality and complex networks. We construct directed and weighted complex networks from time series and use representative network measures to describe their physical and topological properties. Through analyzing the typical dynamical behaviors of some physical models and the MIT-BIH* human electrocardiogram data sets, we show that the proposed approach is able to capture and characterize various dynamics and has much potential for analyzing real-world time series of rather short length

Poverty in Germany: Statistical Inference and Decomposition

Based on six harmonized cross-sections of the German Sample Survey of Income and Expenditure, we study inter-temporal changes in poverty from year 1978 to 2003. Results are decomposed by region and household types, and the bootstrap method is applied to test for the statistical significance of all our findings. Across household types, single parents with children have the highest poverty risk. Most striking is a huge regional divide in poverty which only narrows slightly over the period under investigation: the incidence and the intensity of poverty are substantially higher in the New states. A nonlinear Oaxaca-Blinder decomposition is conducted to quantify the separate contribution of regional differences in households' characteristics to the likelihood of being poor. Estimates from the decomposition indicate that differences in the distributions of socioeconomic characteristics play a negligible role for the 1993 poverty divide. Already in year 2003, however, differences in the distributions of characteristics explain more than fifty percent of the poverty divide, indicating that the poverty divide is likely to become a persistent phenomenon.poverty, Oaxaca-Blinder decomposition, bootstrap, equivalence scale

Production Chains in an Interregional Framework: Identification by Means of Average Propagation Lengths

When linkages between industries are studied from the perspective of production chains, sequencing is important. In this respect, both the strength of the linkages and the distance between industries are relevant. Distance is measured by the average propagation length, defined as the average number of steps it takes a stimulus in one industry to propagate and affect another industry. Using the 1985 intercountry input-output table for six European countries, we present three applications. These are, visualizing the production structure by graphing its production chains, analyzing intercountry linkages between industries, and determining the role that each country plays within the system

Near-field scanning optical microscopic transient lens for carrier dynamics study in InGaN/GaN

Time-resolved microscopic transient lens (TR-M-TL) and near-field scanning optical microscopic transient lens (NSOM-TL) were performed to reveal temporal and spatial behavior of carrier dynamics in InGaN/GaN quantum wells. The carrier and thermal dynamics were observed through the time profile of the TR-M-TL signal. Also, NSOM-photoluminescence and NSOM-TL images were observed at the same time. By comparing these two images, both radiative and nonradiative recombination centers in InGaN active layer were unambiguously discriminated with submicrometer scale. Such nonradiative carrier dynamics has been difficult to observe by conventional techniques in spite of its importance

The German spatial poverty divide: poorly endowed or bad luck?

We study inter-temporal changes in poverty for Germany from year 1978 to 2003, and we employ the bootstrap method to test for statistical significance of results. All results are decomposed by household type and region. Poverty estimates are particularly high for single parents. Most striking, however, is the poverty divide between the old and newly-formed German Federal States, with poverty being significantly higher in the latter. We conduct a nonlinear Oaxaca-Blinder decomposition to quantify the separate contribution of regional differences in households' characteristics to the probability of being poor. --Poverty,decomposition,expenditure patterns,necessities,Oaxaca-Blinder decomposition,bootstrap,equivalence scale

Good English Pronunciation Users and their Pronunciation Learning Strategies

The study investigates pronunciation learning strategies (PLS) deployed by those with good English pronunciation, as well as their beliefs concerning the variables that affect pronunciation competence. In order to collect data for analysis this study surveyed 61 participants who had learned English as a foreign language. They comprised 28 higher education teachers and scholars specialising in English phonetics and phonology, who were defined as good pronunciation users (GPU), and 33 EFL teacher training students, viewed as average pronunciation learners (APL). This cohort responded to a survey on pronunciation learning strategies and expressed their views on several aspects affecting the L2 pronunciation learning process. These aspects were: age of the first contact with L2 (age of onset), motivation, exposure to the target language, the teacher’s pronunciation model, and learning strategies. The study used both open- and close-ended question formats to collect data from both GPU and APL. The analyses of the data helped to create a tentative profile of a successful L2 pronunciation learner