Harmonic Manifolds and Tubes

The authors showed in a preceding paper that in a connected locally harmonic manifold, the volume of a tube of small radius about a regularly parameterized simple arc depends only on the length of the arc and the radius. In this paper, we show that this property characterizes harmonic manifolds even if it is assumed only for tubes about geodesic segments. As a consequence, we obtain similar characterizations of harmonic manifolds in terms of the total mean curvature and the total scalar curvature of tubular hypersurfaces about curves. We find simple formulae expressing the volume, total mean curvature, and total scalar curvature of tubular hypersurfaces about a curve in a harmonic manifold as a function of the volume density function.Comment: 14 pages, grant numbers are update

Further Study of the Gamma-Ray Bursts Duration Distribution

Two classes of gamma-ray bursts have been identified so far, characterized by durations shorter and longer than approximately 2 seconds. In 1998 two independent papers indicated the existence of the third class of the bursts roughly duration between 2 and 10 seconds. In this paper, using the full BATSE Catalog, the maximum likelihood estimation is presented, which gives a 0.5% probability to having only two subclasses. The Monte-Carlo simulation confirms this probability, too.Comment: submitted to A&

Uncertainty of the Od Matrix's Estimation in Urban Public Transport

AbstractThe key of the planning of public transport systems is the accurate prediction of the traffic load which requires a well-functioning assignment method and reliable passenger data (i.e. time-dependent OD matrix). The paper two years ago at TRA2014 was started with this idea. Since that time the procedure was improved and real network test was performed. Based on the experiences of the real network tests several new improvements were implemented. This paper shows the newest results with the previously described method and search for connection between network structure and certainty together with sample size

Recommendation Techniques for smart cities

The bottleneck of event recommender systems is the availability of actual, up-to-date information on events. Usually, there is no single data feed, thus information on events must be crawled from numerous sources. Ranking these sources helps the system to decide which sources to crawl and how often. In this thesis, a model for event source evaluation and ranking is proposed based on well-known centrality measures from social network analysis. Experiments made on real data, crawled from Budapest event sources, shows interesting results for further research

A new approach of analyzing GRB light curves

We estimated the Txx quantiles of the cumulative GRB light curves using our recalculated background. The basic information of the light curves was extracted by multivariate statistical methods. The possible classes of the light curves are also briefly discussed.Comment: 4 pages, 8 figure

Anisotropy of the sky distribution of gamma-ray bursts

The isotropy of gamma-ray bursts collected in current BATSE catalog is studied. It is shown that the quadrupole term being proportional to \sim sin 2b sin l is non-zero with a probability of 99.9%. The occurrence of this anisotropy term is then confirmed by the binomial test even with the probability of 99.97 %. Hence, the sky distribution of all known gamma-ray bursts is anisotropic. It is also argued that this anisotropy cannot be caused exclusively by instrumental effects due to the nonuniform sky exposure of BATSE instrument. Separating the GRBs into short and long subclasses, it is shown that the short ones are distributed anisotropically, but the long ones seem to be distributed still isotropically. The character of anisotropy suggests that the cosmological origin of short GRBs further holds, and there is no evidence for their Galactical origin

Studies on the procyclical behaviour of banks

The three papers in this volume investigate the same subject matter, the procyclicality of banking sector behaviour, from three different perspectives. The first paper of the volume focuses on some regulatory aspects of banks’ procyclical behaviour. The second paper deals both with the depth of financial intermediation and banks’ procyclical behaviour, as in the case of catching-up economies the two subjects are interrelated. The third paper describes some regulatory options that may encourage banks to prepare in due time for a deterioration in loan quality due to changes in the economic environment.Pro-cyclicality, Basel Capital Accord, Credit risk, Provisioning, Regulation.

The three-dimensional carrier-envelope-phase map of focused few-cycle pulsed Gaussian beams

We derive an analytical expression that describes the complete three-dimensional carrier-envelope phase (CEP) distribution of in the focal volume of ultrashort pulsed Gaussian beams focused by spherical mirrors or lenses. The focal CEP map depends on the so-called factor $g$ specifying the frequency-dependence of the beam width of the source few-cycle pulse, on its chirp and on the small chromatic aberration introduced by a lens without appreciably distorting or broadening the few-cycle pulse. We show how to tailor the CEP map of mirror-focused and lens-focused few-cycle pulses in order to produce negligible transversal and axial CEP variations in specific regions of the focal volume for phase-sensitive interactions of light with matter taking place in a volume or on a surface. We propose a quasi-achromatic doublet lens that can implement in practice these tailored CEP distributions.Comment: 9 pages, 6 figure