2,457 research outputs found
Range finding of Alfvén oscillations and direction finding of ion-cyclotron waves by using the ground-based ULF finder
International audienceA new approach to the problem of direction and distance finding of magnetospheric ULF oscillations is described. It is based on additional information about the structure of geoelectromagnetic field at the Earth's surface which is contained in the known relations of the theory of magnetovariation and magnetotelluric sounding. This allows us to widen the range of diagnostic tools by using observations of Alfvén oscillations in the Pc 3?5 frequency band and the ion-cyclotron waves in the Pc 1 frequency band. Preliminary results of the remote sensing of the magnetosphere at low-latitudes using the MHD ranger technique are presented. The prospects for remote sensing of the plasmapause position are discussed
DEVELOPING ROBUST AUTONOMOUS VEHICLES WITH ROS
The demand for autonomous vehicles (AVs) is rising across both military and civilian sectors. These unmanned systems offer numerous advantages, such as improved efficiency, safety, and adaptability. Addressing this demand requires the development of resilient and versatile autonomous vehicles crucial for the transport and reconnaissance markets.
The sensory perception of autonomous vehicles of any kind is paramount to their ability to navigate and localize in their environment. Factors such as sensor noise, erroneous readings, and deliberate attacks should all be considered when developing a robust autonomous system. This work aims to quantify the degradation of sensor data which causes mapping algorithms to fail and properly localize.
In this thesis, we explore five different simulated LIDAR perturbation models and their effects on mapping indoor and outdoor locations. The noise models are categorized into two types: \emph{fake} and \emph{real} point returns. A similarity metric is utilized to quantify the degradation of the resulting point clouds. An advantage of this approach, over implementing perturbations in physical environments, is the ability to test challenging or impractical perturbations on a simulated system.
Our findings confirm that increased levels of noise correlate with elevated errors in mapping. We discuss the process of cascading failures and the additional overlaid topography that is produced. We also discovered that certain types of sensor noise affect indoor mapping more than outdoor, particularly when the noise is localized.
In future research, we plan to investigate methods to physically implement the noise models employed in this study and to develop strategies for mitigating their impact on autonomous navigation
Meat and bone meal as fertilizer for oats - From slaughter house waste to fertilizer
EU permitted in 2006 the use of meat bone meal(MBM) as fertilizer. MTT Agrifood Research Finland's Kannus conducted a field experiment from 2000 to 2003 with a supplement experiment in 2004. The fertilization effect was 24 % higher after MBM than after chemical fertilizers
Meat bone meal as nitrogen and phosphorus fertilizer
Meat bone meal (MBM) contains considerable amount of nutrients (~8 % N, ~ 5 % P and ~ 10 Ca). To quantify and qualify MBM use as an N and P fertilizers, two field experiments were done on spring barley and oat in 2000 and 2001
Bursts of ULF noise excited by sudden changes of solar wind dynamic pressure
International audienceWe present the results of analysis of the dayside magnetic pulsation response to a sudden change in solar wind dynamic pressure. We concentrate on the events when a burst or a series of short-lived bursts in the Pc1 frequency range with the repetition period of 7?15 min were observed on the ground around the local noon. Not every impulse of large amplitude caused this phenomenon. We have found that the ULF bursts were excited when the spectrograms of the DMSP satellites showed a signature of 10?30 keV ions in the vicinity of the magnetic flux tube of the ground observatory, that may be related to a geomagnetic storm preceding the event. In light of this finding a possible model of the phenomenon is suggested in which the hot protons influence significantly both the generation and modulation of Pc1 activity
A Small Interstellar Probe to the Heliospheric Boundary and Interstellar Space
The Small Interstellar Probe m1ss1on would be designed to cross the solar wind
termination shock and the heliopause, and make a significant penetration into nearby
interstellar space. The principal scientific objectives of this mission would be to explore the
structure of the heliosphere, to investigate its interaction with the interstellar medium, and to
explore the nature of the interstellar medium itself. These studies would be carried out by a
~200 kg spacecraft carrying a scientific payload designed to make comprehensive, in situ
measurements of both heliospheric and interstellar plasma, fields, energetic particles, gas, and
dust. New trajectory calculations indicate significantly improved performance over earlier
studies with larger spacecraft, including spacecraft velocities ranging from -6 to -14 AU/yr.,
depending on trajectory and launch vehicle
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