1,794 research outputs found
Strong-field gravitational-wave emission in Schwarzschild and Kerr geometries: some general considerations
We show how the concurrent implementation of the exact solutions of the
Einstein equations, of the equations of motion of the test particles, and of
the relativistic estimate of the emission of gravitational waves from test
particles, can establish a priori constraints on the possible phenomena
occurring in Nature. Two examples of test particles starting at infinite
distance or from finite distance in a circular orbit around a Kerr black hole
are considered: the first leads to a well defined gravitational wave burst the
second to a smooth merging into the black hole. This analysis is necessary for
the study of the waveforms in merging binary systems.Comment: Resubmitted to PRD after Referee repor
Sea state monitoring using coastal GNSS-R
We report on a coastal experiment to study GPS L1 reflections. The campaign
was carried out at the Barcelona Port breaker and dedicated to the development
of sea-state retrieval algorithms. An experimental system built for this
purpose collected and processed GPS data to automatically generate a times
series of the interferometric complex field (ICF). The ICF was analyzed off
line and compared to a simple developed model that relates ICF coherence time
to the ratio of significant wave height (SWH) and mean wave period (MWP). The
analysis using this model showed good consistency between the ICF coherence
time and nearby oceanographic buoy data. Based on this result, preliminary
conclusions are drawn on the potential of coastal GNSS-R for sea state
monitoring using semi-empirical modeling to relate GNSS-R ICF coherence time to
SWH.Comment: All Starlab authors have contributed significantly; the Starlab
author list has been ordered randomly. Submitted to GR
Using E-Maps to Organize and Navigate Web-based Content
Many university faculty create their own websites or use a course management system to upload course materials for online instruction. Course content and files are mostly organized and presented in a linear structure and placed in a series of folders and subfolders. An alternative approach to navigate, organize, and sequence Webbased content is to use a computer generated mind map – an E-Map. With its unique storage and organizational capacity, E-Maps not only provide a user-friendly elearning structure, but also can effectively manage knowledge in a much more efficient manner than using a linear approach to navigate and access Web-based content. The purpose of this article is to examine how E-Maps can be used as a graphical interface for presenting and organizing Web-based course content and files online. Explored in this article is a brief overview of mind maps , mind mapping software, how using E-Maps as a graphic organizer can facilitate learning, and some instructional application examples of using E-Maps for Web-based instruction.Many university faculty create their own websites or use a course management system to upload course materials for online instruction. Course content and files are mostly organized and presented in a linear structure and placed in a series of folders and subfolders. An alternative approach to navigate, organize, and sequence Webbased content is to use a computer generated mind map – an E-Map. With its unique storage and organizational capacity, E-Maps not only provide a user-friendly elearning structure, but also can effectively manage knowledge in a much more efficient manner than using a linear approach to navigate and access Web-based content. The purpose of this article is to examine how E-Maps can be used as a graphical interface for presenting and organizing Web-based course content and files online. Explored in this article is a brief overview of mind maps , mind mapping software, how using E-Maps as a graphic organizer can facilitate learning, and some instructional application examples of using E-Maps for Web-based instruction
Using E-Maps to Organize and Navigate Web-based Content
Many university faculty create their own websites or use a course management system to upload course materials for online instruction. Course content and files are mostly organized and presented in a linear structure and placed in a series of folders and subfolders. An alternative approach to navigate, organize, and sequence Webbased content is to use a computer generated mind map – an E-Map. With its unique storage and organizational capacity, E-Maps not only provide a user-friendly elearning structure, but also can effectively manage knowledge in a much more efficient manner than using a linear approach to navigate and access Web-based content. The purpose of this article is to examine how E-Maps can be used as a graphical interface for presenting and organizing Web-based course content and files online. Explored in this article is a brief overview of mind maps , mind mapping software, how using E-Maps as a graphic organizer can facilitate learning, and some instructional application examples of using E-Maps for Web-based instruction.Many university faculty create their own websites or use a course management system to upload course materials for online instruction. Course content and files are mostly organized and presented in a linear structure and placed in a series of folders and subfolders. An alternative approach to navigate, organize, and sequence Webbased content is to use a computer generated mind map – an E-Map. With its unique storage and organizational capacity, E-Maps not only provide a user-friendly elearning structure, but also can effectively manage knowledge in a much more efficient manner than using a linear approach to navigate and access Web-based content. The purpose of this article is to examine how E-Maps can be used as a graphical interface for presenting and organizing Web-based course content and files online. Explored in this article is a brief overview of mind maps , mind mapping software, how using E-Maps as a graphic organizer can facilitate learning, and some instructional application examples of using E-Maps for Web-based instruction
The Eddy Experiment: accurate GNSS-R ocean altimetry from low altitude aircraft
During the Eddy Experiment, two synchronous GPS receivers were flown at 1 km
altitude to collect L1 signals and their reflections from the sea surface for
assessment of altimetric precision and accuracy. Wind speed (U10) was around 10
m/s, and SWH up to 2 m. A geophysical parametric waveform model was used for
retracking and estimation of the lapse between the direct and reflected signals
with a 1-second precision of 3 m. The lapse was used to estimate the SSH along
the track using a differential model. The RMS error of the 20 km averaged
GNSS-R absolute altimetric solution with respect to Jason-1 SSH and a GPS buoy
measurement was of 10 cm, with a 2 cm mean difference. Multipath and retracking
parameter sensitivity due to the low altitude are suspected to have degraded
accuracy. This result provides an important milestone on the road to a GNSS-R
mesoscale altimetry space mission.Comment: All Starlab authors have contributed significantly; the Starlab
Author list has been ordered randoml
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