Reflection energy from a linear reflector comes from an integrant over an aperture often described by the Fresnel zone. Within the Fresnel zone, the diffraction energy constructively builds the reflection energy. This paper uses diffraction theory to explain the reflector edge effect on amplitude and the amplitude variation within the Fresnel zone. Thus, discuss the Fresnel zone effect for AVO ...

The vision of the Electronic Geophysical Year (eGY) is that we can achieve a major step forward in geoscience capability, knowledge, and usage throughout the world for the benefit of humanity by accelerating the adoption of modern and visionary practices such as virtual observatories for managing and sharing data and information. eGY has found that the biggest challenges to implementing the vis...

Factors affecting vehicle occupancy measurement were examined with the aim of improving state vehicle occupancy monitoring programs. A comparison was conducted of five data sets looking at the effects on average vehicle occupancy (AVO) of time of day, day of week, road types, HOV lanes, locational differences, and traffic volume. It was found that AVO was higher in the afternoons, on Saturdays,...

The Virtual Observatory (VO) is realizing global electronic integration of astronomy data. One of the long-term goals of the U.S. VO project, the Virtual Astronomical Observatory (VAO), is development of services and protocols that respond to the growing size and complexity of astronomy data sets. This paper describes how VAO staff are active in such development efforts, especially in innovativ...

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Here we review some of the main issues related to multi-wavelength source identification and characterization, with particular emphasis on the field of X-ray surveys carried out over the last years. This complex and time-consuming process is going to represent one of the main difficulties over the coming years, when significantly larger surveys, both in area and depth, will be carried out with ...

Феномен мощного радиоизлучения ядра галактики является кратковременной по космологическим масштабам (до ~10лет) эволюционной фазой самых массивных звездных систем, поэтому информация о статистических свойствах радиоисточников в разных диапазонах электромагнитного спектра важна для понимания природы и эволюции галактик. Программные средства виртуальной обсерватории (ВО), разработанные за последн...

Experience with ASTROVIRTEL, scientific analysis of current large data sets, and detailed preparation for the truly huge future missions especially GAIA, provide important lessons for the Astrophysical Virtual Observatory. They demonstrate that the science cases are impressive, specifically allowing new thresholds to be crossed. The AVO is more than just faster cheaper better, it allows the new...

muḥyī al-dīn maghribī is among the few astronomers of the middle ages whose astronomical system is entirely based on new measures of planetary parameters and whose measurement of the observational data and calculation processes for determining their amount have been carried out in maragha observatory. he has explained the details of his observations and calculations in a volume called talkhīṣ a...

Aims. We study the visibility of sunspots and its influence on observed values of sunspot region parameters. Methods. We use Virtual Observatory tools provided by AstroGrid to analyse a sample of 6862 sunspot regions. By studying the distributions of locations where sunspots were first and last observed on the solar disk, we derive the visibility function of sunspots, the rate of magnetic flux ...