Many important techniques for investigating the properties of extragalactic radio sources, such as spectral-index and rotation-measure mapping, involve the comparison of images at two or more frequencies. In the case of radio interferometric data, this can be done by comparing the CLEAN maps obtained at the different frequencies. However, intrinsic differences in images due to the frequency dep...

Rogue seasonality or unintended cyclic variability in order and other supply chain variables is an endogenous disturbance generated by a company’s internal processes such as inventory and production control systems. The ability to automatically detect, diagnose and discriminate rogue seasonality from exogenous disturbances is of prime importance to decision makers. This paper compares the effec...

We analyse 15 XMM–Newton observations of the Seyfert galaxy NGC 4051 obtained over 45 d to determine the ultraviolet (UV) light curve variability characteristics and search for correlated UV/X-ray emission. The UV light curve shows variability on all time-scales, however with lower fractional rms than the 0.2–10 keV X-rays. On days–weeks time-scales the fractional variability of the UV is Fvar ...

Objective quality assessment methods have been used widely for evaluation of audio coding systems. However, even though many different competing multi-channel audio compression coding systems are being developed, most current quality assessment methods only predict results for monaural or stereo signals. In this paper, a prediction method is introduced that can be used for multi-channel audio c...

We investigate the angular distribution of gamma-ray bursts using the largest catalog of welllocalized events that is currently available—combined BATSE/Ulysses burst locations. We present the preliminary spatial analysis of 415 BATSE/Ulysses bursts included in the BATSE 4B catalog. We find that the locations are consistent with largeand small-scale isotropy, with no significant clustering or r...

We investigate the luminosity dependence of quasar clustering, inspired by numerical simulations of galaxy mergers that incorporate black hole growth. These simulations have motivated a new interpretation of the quasar luminosity function. In this picture, the bright end of the quasar luminosity function consists of quasars radiating nearly at their peak luminosities, while the faint end consis...

The observation of variability in astronomical systems provides astronomers with valuable information on the physical nature of the system. The types of variability which astronomers deal with can be periodic, quasi-periodic, or aperiodic. We collect and describe a number of time series data sets which exemplify the types of problems encountered by the modern astronomer and which demonstrate so...

This paper presents an evaluation of different types and families of multiwavelets in stereo correspondence matching. First, the paper introduces two hierarchical stereo matching techniques based on balanced and respectively unbalanced multiwavelet transforms, which employ normalized cross correlation to search for disparities. Different multiwavelet families, with different properties and filt...

We investigate the problem of automatically determining what type of shoe left an impression found at a crime scene. This recognition problem is made difficult by the variability in types of crime scene evidence (ranging from traces of dust or oil on hard surfaces to impressions made in soil) and the lack of comprehensive databases of shoe outsole tread patterns. We find that mid-level features...

We present the discovery of optical/X-ray flux correlations on rapid timescales in the low/hard state of the Galactic black hole GX 339–4. The source had recently emerged from outburst and was associated with a relatively-faint counterpart with mag V ≈17. The optical (VLT/ULTRACAM) and X-ray (RXTE/PCA) data show a clear positive cross-correlation function (CCF) signal, with the optical peak lag...