117,716 research outputs found
3D/2D object-based coding of head MRI data
No full textWe propose a coding system featuring 3D encoding/2D decoding object-based functionalities. Any object of any 2D image of the dataset can be recovered at a finely graded up to lossless quality. Compression is improved by exploiting the full correlation among data samples by means of 3D DWT. A swift access to 2D images is obtained by enabling 2D decoding. Given the index of the image of interest along the z axis, only the concerned portion of the bitstream is decoded, at the desired quality. The selective access to data can be improved by splitting the image in regions corresponding to the different objects. Then, a suitable ordering of the encoded information within the bitstream enables random access to any object at the desired rate. This enables a pseudo-lossless regime, where the diagnostically relevant parts of the image are represented without loss, while a lower quality is assumed to be acceptable for the others. Results show that the proposed system is a good compromise between the gain in compression efficiency provided by 3D systems and the fast access to the data of 2D ones
Variability of blowfly head optomotor responses
No full textRosner R, Egelhaaf M, Grewe J, Warzecha A-K. Variability of blowfly head optomotor responses. Journal of Experimental Biology. 2009;212(8):1170-1184
Impact of climate variability on tropospheric ozone
No full textA simulation with the climate–chemistry model (CCM) E39/C is presented, which covers both the troposphere and stratosphere
dynamics and chemistry during the period 1960 to 1999. Although the CCM, by its nature, is not exactly representing observed
day-by-day meteorology, there is an overall model's tendency to correctly reproduce the variability pattern due to an inclusion of
realistic external forcings, like observed sea surface temperatures (e.g. El Niño), major volcanic eruption, solar cycle,
concentrations of greenhouse gases, and Quasi-Biennial Oscillation. Additionally, climate–chemistry interactions are included, like
the impact of ozone, methane, and other species on radiation and dynamics, and the impact of dynamics on emissions (lightning).
However, a number of important feedbacks are not yet included (e.g. feedbacks related to biogenic emissions and emissions due to
biomass burning). The results show a good representation of the evolution of the stratospheric ozone layer, including the ozone
hole, which plays an important role for the simulation of natural variability of tropospheric ozone. Anthropogenic NOx emissions
are included with a step-wise linear trend for each sector, but no interannual variability is included. The application of a number of
diagnostics (e.g. marked ozone tracers) allows the separation of the impact of various processes/emissions on tropospheric ozone
and shows that the simulated Northern Hemisphere tropospheric ozone budget is not only dominated by nitrogen oxide emissions
and other ozone pre-cursors, but also by changes of the stratospheric ozone budget and its flux into the troposphere, which tends to
reduce the simulated positive trend in tropospheric ozone due to emissions from industry and traffic during the late 80s and early
90s. For tropical regions the variability in ozone is dominated by variability in lightning (related to ENSO) and stratosphere–
troposphere exchange (related to Northern Hemisphere Stratospheric dynamics and solar activity). Since tropospheric background
chemistry is regarded only, the results are quantitatively limited with respect to derived trends. However, the main results are
regarded to be robust.
Although the horizontal resolution is rather coarse in comparison to regional models, such kind of simulations provide useful
and necessary information on the impact of large-scale processes and inter-annual/decadal variations on regional air quality
Multirate coding of 3D medical data
No full textThe last generation medical imaging equipment produce multidimensional (3D or 3D+time) data distributions. On a coding perspective, it is reasonable to expect that the exploitation of the full dimensional correlation among data samples would lead to a sensible improvement in compression performances, especially for isotropic datasets. We propose a fully three-dimensional wavelet-based coding system providing a finely-graded up to lossless data representation in a single bistream. The data are first decorrelated by a 3D discrete wavelet transform, performed by the non-linear lifting scheme mapping integers to integers. This enables the lossless mode and permits the in-place implementation of the transform at a reduced computational complexity. The coding scheme is inspired to the layered-zero coding proposed by Taubman and Zakhor (1994), extended to handle fully 3D subband structures. Performances are characterized with respect to both the 2D version of the same algorithm and the JPEG standard. The rate-saving is strongly influenced by the amount of the data correlation in the z dimension, ranging between 16.5% and 5.5% for the considered datasets
Le Conseil de Securité et le contrôle du juge
No full textThis article makes a comparison between the case law of international courts (already examined by the author in another contribution published in the "European Journal of International Law", 2009), and the case law of domestic courts concerning UN and EU targeted sanctions, adopted in the framework of the fight against terrorism. It argues that the said courts have adopted different theoretical approaches, as far as art. 103 of the United Nations Charter is concerned. These approaches are investigated in depth in paragraphs III and IV. In paragraph V, section A, some observations are submitted, aimed at explaining the (legal) reasons behind such different approaches. Some critical reflections focussed particularly on the general approach chosen by the domestic Courts are developed in the folloving section. Finally, the author argues that the theoretical model of the "Balancing of values", adopted by the European Court of Justice in the Kadi Judgment, could be followed also by domestic Courts (by having recourse to domestic constitutional values), in order to counterbalance the legal effects of anti-terrorism measures. Some domestic judgments going this way are examined in the (final) “Addendum”
Comparison between global models and measurements of trace gases during TROCCINOX
No full textAirborne trace gas measurements carried out over southern Brazil during TROCCINOX-1 with the Falcon aircraft are compared to results from three global models: ECHAM, MATCH and TM4. The agreement between the models, with different parameterizations for lightning-produced NOX (=NO+NO2), and the measurements is investigated along single flight tracks. A new parameterization based on the mass flux in the updrafts [Grewe et al., 2001; Kurz and Grewe, 2002] shows promising results in comparison to the more commonly used parameterization based on the cloud top height [Price and Rind, 1992]. The most realistic model results for the total amount of lightning-produced NOX on the global scale were achieved with 5 Tg(N) yr-1
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Climate Impact of a Potential Supersonic Fleet
No full textWithin the EU-project SCENIC the impact of a potential
supersonic fleet has been investigated. The methodology
how to estimate its climate impact is presented. A number
of sensitivity studies are analysed to identify options to
minimise climate impact. Since stratospheric water vapour
emissions are the most important contributor to climate
change induced by supersonics those scenarios are
minimising the climate impact which have the lowest cruise
altitude.
In order to include climate aspects in multi-disciplinary
optimisation for supersonics an assessment tool (AirClim)
has been developed within the EU Integrated Project
HISAC, which is briefly presented. The main atmospheric
input data describe the atmosphere’s sensitivity to the
emission region. Based hereon a functional relationship
has been developed between basic (supersonic) aircraft
design parameters (cruise altitude, fuel consumption) and
climate change
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