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Search Results: 1 - 10 of 121074 matches for " T. Nissen-Meyer "
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Triplicated P-wave measurements for waveform tomography of the mantle transition zone
S. C. St hler, K. Sigloch,T. Nissen-Meyer
Solid Earth (SE) & Discussions (SED) , 2012, DOI: 10.5194/se-3-339-2012
Abstract: Triplicated body waves sample the mantle transition zone more extensively than any other wave type, and interact strongly with the discontinuities at 410 km and 660 km. Since the seismograms bear a strong imprint of these geodynamically interesting features, it is highly desirable to invert them for structure of the transition zone. This has rarely been attempted, due to a mismatch between the complex and band-limited data and the (ray-theoretical) modelling methods. Here we present a data processing and modelling strategy to harness such broadband seismograms for finite-frequency tomography. We include triplicated P-waves (epicentral distance range between 14 and 30°) across their entire broadband frequency range, for both deep and shallow sources. We show that is it possible to predict the complex sequence of arrivals in these seismograms, but only after a careful effort to estimate source time functions and other source parameters from data, variables that strongly influence the waveforms. Modelled and observed waveforms then yield decent cross-correlation fits, from which we measure finite-frequency traveltime anomalies. We discuss two such data sets, for North America and Europe, and conclude that their signal quality and azimuthal coverage should be adequate for tomographic inversion. In order to compute sensitivity kernels at the pertinent high body wave frequencies, we use fully numerical forward modelling of the seismic wavefield through a spherically symmetric Earth.
Triplicated P-wave measurements for waveform tomography of the mantle transition zone
S. C. St?hler,K. Sigloch,T. Nissen-Meyer
Solid Earth Discussions , 2012, DOI: 10.5194/sed-4-783-2012
Abstract: Triplicated body waves sample the mantle transition zone more extensively than any other wave type, and interact strongly with the discontinuities at 410 km and 660 km. Since the seismograms bear a strong imprint of these geodynamically interesting features, it is highly desirable to invert them for structure of the transition zone. This has rarely been attemped, due to the mismatch between the complex and bandlimited data and the (ray-theoretical) modeling methods. Here we present a data processing and modeling strategy to harness such broadband seismograms for finite-frequency tomography. We include triplicated P-waves (epicentral distance range between 14 and 30°) across their entire broadband frequency range, for both deep and shallow sources. We show that it is possible to predict the complex sequence of arrivals in these seismograms, but only after a careful effort to estimate source time functions and other source parameters from data, variables that strongly influence the waveforms. Modeled and observed waveforms then yield decent cross-correlation fits, from which we measure finite-frequency traveltime anomalies. We discuss two such data sets, for North America and Europe, and conclude that their signal quality and azimuthal coverage should be adequate for tomographic inversion. In order to compute sensitivity kernels at the pertinent high body-wave frequencies, we use fully numerical forward modelling of the seismic wavefield through a spherically symmetric earth.
REPERCUSIóN DE UN SISTEMA DE RECONOCIMIENTO DEL HABLA INTEGRADO EN UN PACS/RIS CON RESPECTO AL TIEMPO INVERTIDO EN ELABORAR Y PONER A DISPOSICIóN LOS INFORMES RADIOLóGICOS
Trumm,C. G; Glaser,C; Paasche,V; Crispin,A; Popp,P; Küttner,B; Francke,M; Nissen-Meyer,S; Reiser,M;
Revista chilena de radiología , 2008, DOI: 10.4067/S0717-93082008000200007
Abstract: purpose: quantification of the impact of a pacs/ris-integrated speech recognition system (srs) on the time expenditure for radiology reporting and on hospital-wide report availability (ra) in a university institution. material and methods: in a prospective pilot study, the following parameters were assessed for 669 radiographic examinations (cr): 1. time requirement per report dictation (ted: dictation time (s)/number of images (examination) x number of words (report)) with either a combination of pacs/ tape-based dictation (td: analog dictation device/ minicassette/transcription) or pacs/ris/speech recognition system(rr: remote recognition/transcription and or: online recognition/self-correction by radiologist), respectively, and 2. the reporttur-naround time (rtt) as the time interval from the entryof the first image into the pacs to the available ris/his report. two equal time periods were chosen retrospectively from the ris database: 11/2002-2/2003 (only td) and 11/2003-2/2004 (only rr or or with speech recognition system (srs)). the midterm (> 24 h, 24 h intervals) and short-term (< 24 h, 1 h intervals) ra after examination completion were calculated for all modalities and for cr, ct, mr andxa/ds separately. the relative increase in the mid-term ra (rimra: related to total number of examinations in each time period) and increase in the short-term ra (isra: ratio of available reports during the 1st to 24th hour) were calculated. results: prospectively there was a significant difference between td/rr/or (n = 151/257/261) regarding mean ted (0.44/0.54/0.62 s (per word and image)) and mean rtt.
The Development of a Data-Centred Conceptual Reference Model for Strategic GRC-Management  [PDF]
Volker Nissen, Wolfgang Marekfia
Journal of Service Science and Management (JSSM) , 2014, DOI: 10.4236/jssm.2014.72007
Abstract:

Until now there are only few ideas for an integrated governance, risk and compliance (GRC) management available with these referring to the management process of GRC only. In literature, mainly specific questions at a detailed level, like the automation of different controls, are discussed in the GRC context. To be in the position to entirely realise benefit potentials (e.g. improvement of processes), it is necessary to have an integrated GRC-Management focusing on the strategic business objectives. Starting from the requirements, this article deals with general guidelines for strategic GRC-Management showing which aspects have to be considered in terms of an integral approach. On this basis, a data-centred reference model explicates the structural connections of GRC-related data, and lays the basis for the implementation in practice.

Portraying the Social Dimensions of Consulting with Structuration Theory  [PDF]
Christian Mauerer, Volker Nissen
Journal of Service Science and Management (JSSM) , 2014, DOI: 10.4236/jssm.2014.72010
Abstract:

In this paper, we argue that the consultant-client relationship is of central importance for consulting engagements. The paper therefore outlines the social dimensions that are inherent in the consulting system due to its characteristics that create social complexity. To gain further insights into the social interaction scheme and dynamics of consulting projects, a conceptualization based on an appropriate theoretical model is required. We propose to utilize the Structuration Theory for the compilation of the social context of consulting, as this provides a framework for incorporating the social determinants, focuses on actions of human-beings, and additionally allows the identification of interrelated dependencies of structure and actions.

Lithium abundances for 185 main-sequence stars - Galactic evolution and stellar depletion of lithium
Y. Q. Chen,P. E. Nissen,T. Benoni,G. Zhao
Physics , 2001, DOI: 10.1051/0004-6361:20010371
Abstract: We present a survey of lithium abundances in 185 main- sequence field stars with Teff between 5600 and 6600 K and [Fe/H] from -1.4 to +0.2 based on high-resolution spectra of 130 stars and a reanalysis of data from Lambert et al. (1991). The survey takes advantage of improved ways of determining effective temperature, metallicity, mass and age, offering an opportunity to investigate the behaviour of Li as a function of these parameters. An interesting result is the presence of a large gap in the Li-Teff plane, which distinguishes `Hyades-like, Li-dip' stars from other stars. These Li-dip stars have a well-defined mass, which decreases with metallicity. Stars above the gap, when divided into four metallicity groups, may show a correlation between Li abundance and stellar mass, but with a large dispersion that cannot be explained by observational errors or differences in metallicity and age, which ranges from 1.5 to 15 Gyr. This suggests that Li depletion occurs early in stellar life and that other parameters, e.g. initial rotation velocity and/or the rate of angular momentum loss, affect the degree of depletion. A comparison of the distribution of stars in the Li-[Fe/H] plane with evolutionary models of Romano et al. (1999) suggests that novae are a major source for the Li production in the Galactic disk.
O uso de cloro na desinfec??o de águas, a forma??o de trihalometanos e os riscos potenciais à saúde pública
Meyer, Sheila T.;
Cadernos de Saúde Pública , 1994, DOI: 10.1590/S0102-311X1994000100011
Abstract: before the development of the germ theory relating microorganisms with disease transmission (1880) people believed that diseases were transmitted by odours. water and sewage disinfection emerged as a method for elimination of odours. there are many disinfecting agents, but chlorine is the main product used to disinfect water. organic compounds present in water that is chlorinated can result in the formation of trihalomethanes. the latter are basically one atom of carbon, one of hydrogen, and three of a halogen (chlorine, bromine, or iodine). these are considered carcinogenic compounds and their presence in drinking water should therefore be avoided. epidemiological research has shown an association between trihalomethane concentration and cancer morbidity and mortality for some types of carcinoma. nevertheless, there may be more risk than benefit involved in replacing chlorine with other disinfecting agents, since the incidence of water-borne diseases only dropped after water chlorination became a routine procedure.
O uso de cloro na desinfec o de águas, a forma o de trihalometanos e os riscos potenciais à saúde pública
Meyer Sheila T.
Cadernos de Saúde Pública , 1994,
Abstract: Antes do desenvolvimento da teoria dos microorganismos como causadores de doen as (1880), acreditava-se que estas eram transmitidas através de odores. A desinfec o, tanto da água de abastecimento como dos esgotos, surgiu como uma tentativa da elimina o desses odores. Existem muitos agentes desinfetantes, mas, em geral, o cloro é o principal produto utilizado na desinfec o de águas de abastecimento. A presen a de compostos organicos em águas que sofrem o processo de clora o resulta na forma o dos trihalometanos, compostos formados por um átomo de carbono, um de hidrogênio e três de halogênio (cloro, bromo, i do). Os trihalometanos s o considerados compostos carcinogênicos e sua presen a na água deve ser evitada. Levantamentos epidemiológicos relacionando a concentra o dos trihalometanos com a morbidade e a mortalidade por cancer evidenciaram associa es positivas em alguns casos de carcinomas. Entretanto, a substitui o do cloro por outro desinfetante no tratamento da água pode trazer mais riscos do que benefícios, considerando-se que a diminui o da incidência de doen as transmissíveis pela água somente foi alcan ada com a difus o do emprego da técnica de clora o.
Admissible and Restrained Revision
R. Booth,T. Meyer
Computer Science , 2011, DOI: 10.1613/jair.1874
Abstract: As partial justification of their framework for iterated belief revision Darwiche and Pearl convincingly argued against Boutiliers natural revision and provided a prototypical revision operator that fits into their scheme. We show that the Darwiche-Pearl arguments lead naturally to the acceptance of a smaller class of operators which we refer to as admissible. Admissible revision ensures that the penultimate input is not ignored completely, thereby eliminating natural revision, but includes the Darwiche-Pearl operator, Nayaks lexicographic revision operator, and a newly introduced operator called restrained revision. We demonstrate that restrained revision is the most conservative of admissible revision operators, effecting as few changes as possible, while lexicographic revision is the least conservative, and point out that restrained revision can also be viewed as a composite operator, consisting of natural revision preceded by an application of a "backwards revision" operator previously studied by Papini. Finally, we propose the establishment of a principled approach for choosing an appropriate revision operator in different contexts and discuss future work.
Editorial
Morten Nissen
Outlines : Critical Practice Studies , 2002,
Abstract:
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