1,327 research outputs found

    Trajectory similarity analysis in movement parameter space

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    This paper introduces a similarity analysis method for moving object trajectories. The proposed method assesses the similarity between a set of trajectories in a multidimensional space, whose dimensions are formed by different movement parameters (e.g. position, speed, acceleration, direction), plus time. We investigate the applicability of the proposed method in finding relative movement patterns such as coincidence and concurrence in the movement of North Atlantic hurricanes

    Designs of Langmuir Probes for W7-X

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    Exploring movement – similarity analysis of moving objects

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    Extracting knowledge about the movement of different types of mobile agents (e.g. human, animals, vehicles) and dynamic phenomena (e.g. hurricanes) requires new exploratory data analysis methods for massive movement datasets. Different types of moving objects share similarities but also express differences in terms of their dynamic behavior and the nature of their movement. Extracting such similarities can significantly contribute to the prediction, modeling and simulation dynamic phenomena. Therefore, with the development of a quantitative methodology this research intends to investigate and explore similarities in the dynamics of moving objects by using methods of GIScience in knowledge discovery. This paper presents a summary of the ongoing Ph.D. research project

    The economics of mandatory security breach reporting to authorities

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    Legislators in many countries enact security breach notification regulation to address a lack of information security. The laws designate authorities to collect breach reports and advise firms. We devise a principal–agent model to analyze the economic effect of mandatory security breach reporting to authorities. The model assumes that firms (agents) have few incentives to unilaterally report breaches. To enforce the law, regulators (principals) can introduce security audits and sanction noncompliance. However, audits cannot differentiate between concealment and nescience of the agents. Even under optimistic assumptions regarding the effectiveness of mandatory security breach reporting to authorities in reducing individual losses, our model predicts that it may be difficult to adjust the sanction level such that breach notification laws generate social benefit

    Historicism

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    As the rebuilding of Berlin’s eighteenth-century Stadtschloss nears completion, German History turns its attention to the phenomenon of historicism: to the recreation of historical artefacts and practices (sometimes at astonishing expense). Historicism reached its high point in the nineteenth century, when individuals and communities turned to the medieval period to address some of the challenges of modernization. But the urge to revive extended back into the medieval period itself and continues into the twenty-first century. What motivated and what continues to motivate such recreations? As a theme, historicism provides an opportunity for fruitful dialogue between premodern and modern scholars. It also challenges us as historians to consider the value of revivals, whether produced by Berlin politicians, by Hollywood filmmakers or by medieval re-enactors. What happens — or what should happen — when academic scholarship encounters..

    Increasing concentrations of dichloromethane, CH2Cl2, inferred from CARIBIC air samples collected 1998–2012

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    Atmospheric concentrations of dichloromethane, CH2Cl2, a regulated toxic air pollutant and minor contributor to stratospheric ozone depletion, were reported to have peaked around 1990 and to be declining in the early part of the 21st century. Recent observations suggest this trend has reversed and that CH2Cl2 is once again increasing in the atmosphere. Despite the importance of ongoing monitoring and reporting of atmospheric CH2Cl2, no time series has been discussed in detail since 2006. The CARIBIC project (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) has analysed the halocarbon content of whole-air samples collected at altitudes of between ~10–12 km via a custom-built container installed on commercial passenger aircraft since 1998, providing a long-term record of CH2Cl2 observations. In this paper we present this unique CH2Cl2 time series, discussing key flight routes which have been used at various times over the past 15 years. Between 1998 and 2012 increases were seen in all northern hemispheric regions and at different altitudes, ranging from ~7–10 ppt in background air to ~13–15 ppt in regions with stronger emissions (equating to a 38–69% increase). Of particular interest is the rising importance of India as a source of atmospheric CH2Cl2: based on CARIBIC data we provide regional emission estimates for the Indian subcontinent and show that regional emissions have increased from 3–14 Gg yr^-1 (1998–2000) to 16–25 Gg yr^-1 (2008). Potential causes of the increasing atmospheric burden of CH2Cl2 are discussed. One possible source is the increased use of CH2Cl2 as a feedstock for the production of HFC-32, a chemical used predominantly as a replacement for ozone-depleting substances in a variety of applications including air conditioners and refrigeration

    Mining candidate causal relationships in movement patterns

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    This is an Accepted Manuscript of an article published by Taylor & Francis in the International Journal of Geographical Information Science on 01 October 2013, available online: http://wwww.tandfonline.com/10.1080/13658816.2013.841167In many applications, the environmental context for, and drivers of movement patterns are just as important as the patterns themselves. This paper adapts standard data mining techniques, combined with a foundational ontology of causation, with the objective of helping domain experts identify candidate causal relationships between movement patterns and their environmental context. In addition to data about movement and its dynamic environmental context, our approach requires as input definitions of the states and events of interest. The technique outputs causal and causal-like relationships of potential interest, along with associated measures of support and confidence. As a validation of our approach, the analysis is applied to real data about fish movement in the Murray River in Australia. The results demonstrate the technique is capable of identifying statistically significant patterns of movement indicative of causal and causal-like relationships. 1365-8816Australian Research Council Discovery Projec

    Исследование закономерностей развития структурно-химической неоднородности в разнородном сварном соединении трубопроводного переходника

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    Данная работа посвящена исследованию структурно-химической неоднородности (СХН) трубопроводного переходника из разнородных сталей, выполненного аргонодуговой сваркой (АрДС). При помощи оптического микроскопа получены фотографии СХН и ее размеры. СХН выражается в появлении прослоек (карбидной и ферритной) с разным химическим составом. Приведены графики роста ширин прослоек от времени выдержки и температуры.This paper is devoted to the comparison of the structural and chemical inhomogeneity (SCI) of adapters made of dissimilar steels, made by tungsten insert gas (TIG). By means of optical microscope, photographs of the SCI and its dimensions were obtained. SCI is expressed in the appearance of interlayers (carbide and ferritic) with different chemical composition. Graphs of the growth of the widths of the interlayers from the time of exposure and temperature are given

    Specific heat of single crystal MgB_2: a two-band superconductor with two different anisotropies

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    Heat-capacity measurements of a 39 microgramm MgB_2 single crystal in fields up to 14 T and below 3 K allow the determination of the low-temperature linear term of the specific heat, its field dependence and its anisotropy. Our results are compatible with two-band superconductivity, the band carrying the small gap being isotropic, that carrying the large gap having an anisotropy of ~ 5. Three different upper critical fields are thus needed to describe the superconducting state of MgB2.Comment: 4 pages, 4 figures - V2: Bibliography updated and some typo corrected. One reference added - V3: version accepted for publication in PRL, changes made in the tex

    Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air

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    The stratospheric degradation of chlorofluorocarbons (CFCs) releases chlorine, which is a major contributor to the destruction of stratospheric ozone (O3). A recent study reported strong chlorine isotope fractionation during the breakdown of the most abundant CFC (CFC-12, CCl2F2, Laube et al., 2010a), similar to effects seen in nitrous oxide (N2O). Using air archives to obtain a long-term record of chlorine isotope ratios in CFCs could help to identify and quantify their sources and sinks. We analyse the three most abundant CFCs and show that CFC-11 (CCl3F) and CFC-113 (CClF2CCl2F) exhibit significant stratospheric chlorine isotope fractionation, in common with CFC-12. The apparent isotope fractionation (εapp) for mid- and high-latitude stratospheric samples are (-2.4±0.5) ‰ and (-2.3±0.4) ‰ for CFC-11, (-12.2±1.6) ‰ and (-6.8±0.8) ‰ for CFC-12 and (-3.5±1.5) ‰ and (-3.3±1.2) ‰ for CFC-113, respectively. Assuming a constant isotope composition of emissions, we calculate the expected trends in the tropospheric isotope signature of these gases based on their stratospheric 37Cl enrichment and stratosphere-troposphere exchange. We compare these projections to the long-term δ(37Cl) trends of all three CFCs, measured on background tropospheric samples from the Cape Grim air archive (Tasmania, 1978 – 2010) and tropospheric firn air samples from Greenland (NEEM site) and Antarctica (Fletcher Promontory site). From 1970 to the present-day, projected trends agree with tropospheric measurements, suggesting that within analytical uncertainties a constant average emission isotope delta is a compatible scenario. The measurement uncertainty is too high to determine whether the average emission isotope delta has been affected by changes in CFC manufacturing processes, or not. Our study increases the suite of trace gases amenable to direct isotope ratio measurements in small air volumes (approximately 200 ml), using a single-detector gas chromatography-mass spectrometry system
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