Sharif Digital Repository

The left-hand side of the auroral hiss emission observed by Galileo has a frequency time profile shaped very similar to the funnel shape observed in the Earth's auroral region. This close similarity indicates that we can use the theory of whistler-mode propagation near the resonance cone to locate the emission source. The general characteristics of the whistler mode are discussed. Then the position of the emission source is investigated using a geometrical method that takes into account the trajectory of Galileo. Initially a point source is assumed. Then the possibility of a sheet source aligned along the magnetic field lines which are tangent to the surface of Io is investigated. Both types... 

Techniques of production data analysis for single-phase oil and gas reservoirs have advanced significantly over the past few years. These techniques range from traditional (i.e., Arps, 1945; Fetkovich, 1980) to modern methods that account for the variation of operating conditions at the wellbore. However, the application of these later methods to gas condensate reservoirs is a challenge. The authors aimed to extend the applicability of modern production data analysis (single-phase flow) to analyze the production data of a gas condensate reservoir (two-phase flow). A single-phase production model consists of (a) a material balance equation, (b) the solution of diffusivity equation for gas... 

Techniques of production data analysis for single-phase oil and gas reservoirs have advanced significantly over the past few years. These techniques range from traditional (i.e., Arps, 1945; Fetkovich, 1980) to modern methods that account for the variation of operating conditions at the wellbore. However, the application of these later methods to gas condensate reservoirs is a challenge. The authors aimed to extend the applicability of modern production data analysis (single-phase flow) to analyze the production data of a gas condensate reservoir (two-phase flow). A single-phase production model consists of (a) a material balance equation, (b) the solution of diffusivity equation for gas... 

Following the approach of the induced-matter theory, we investigate the cosmological implications of a five-dimensional Brans-Dicke (BD) theory, and propose to explain the acceleration of the universe. After inducing in a four-dimensional hypersurface, we classify the energy-momentum tensor into two parts in a way that, one part represents all kind of the matter (the baryonic and dark) and the other one contains every extra terms emerging from the scale factor of the fifth dimension and the scalar field, which we consider as the energy-momentum tensor of dark energy. We also separate the energy-momentum conservation equation into two conservation equations, one for matter and the other for... 

We present high-precision photometry of two transit events of the extrasolar planetary system WASP-5, obtained with the Danish 1.54-m telescope at European Southern Obseratory La Silla. In order to minimize both random and flat-fielding errors, we defocused the telescope so its point spread function approximated an annulus of diameter 40 pixel (16 arcsec). Data reduction was undertaken using standard aperture photometry plus an algorithm for optimally combining the ensemble of comparison stars. The resulting light curves have point-to-point scatters of 0.50 mmag for the first transit and 0.59 mmag for the second. We construct detailed signal-to-noise ratio calculations for defocused... 

This paper addresses a new approach to segmentation and classification of audio through analysis of a smaller set of selective frames, which are identified by temporal decomposition (TD). These frames are located at the most steady instants, or event centroids, within a given block of the signal, which yield the maximal diversity over the set of selected features. Based on this selection scheme, the number of frames used in the analysis is reduced by at least 40%, while the temporal resolution is doubled as compared to that in typical audio classifiers. By constructing a classification system to segment audio into speech, music, speech-music, and others, it is shown that the proposed method... 

Gas chromatography-mass spectrometry (GC-MS) and comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC-MS) are powerful techniques for measurement of all metabolites in complex metabolic samples. However, analyzing GC-MS and especially GC×GC-MS metabolomic data is a major challenge to the researchers in the field of metabolomics mainly due to the complexity and large data size. In this regard, an automated R based software entitled RMet has been developed to overcome the challenges in the metabolomic analysis workflow of GC-MS and GC×GC-MS data sets. Additionally, it is able to facilitate the complex process of extracting reliable and useful biological information from... 

Discussing the particularly long gravitational microlensing event OGLE-2014-BLG-1186 with a time-scale tE ∼ 300 d, we present a methodology for identifying the nature of localised deviations from single-lens point-source light curves, which ensures that (1) the claimed signal is substantially above the noise floor, (2) the inferred properties are robustly determined and their estimation is not subject to confusion with systematic noise in the photometry, (3) alternative viable solutions within the model framework are not missed. Annual parallax and binarity could be separated and robustly measured from the wing and the peak data, respectively. We find matching model light curves that involve... 

Ultra-high-energy (E > 100 TeV) Extensive Air Showers (EASs) have been monitored for a period of five years (1997-2003), using a small array of scintillator detectors in Tehran, Iran. The data have been analyzed taking into account the dependence of source counts on zenith angle. During a calendar year different sources come into the field of view of the detector at varying zenith angles. Because of varying thickness of the overlaying atmosphere, the shower count rate is extremely dependent on zenith angle, which has been carefully analyzed over time (Bahmanabadi et al. 2002, Exp. Astron., 13, 39). High energy gamma-ray sources from the EGRET third catalogue where observed and the data were...