785 research outputs found
Trajectory Clustering and an Application to Airspace Monitoring
This paper presents a framework aimed at monitoring the behavior of aircraft
in a given airspace. Nominal trajectories are determined and learned using data
driven methods. Standard procedures are used by air traffic controllers (ATC)
to guide aircraft, ensure the safety of the airspace, and to maximize the
runway occupancy. Even though standard procedures are used by ATC, the control
of the aircraft remains with the pilots, leading to a large variability in the
flight patterns observed. Two methods to identify typical operations and their
variability from recorded radar tracks are presented. This knowledge base is
then used to monitor the conformance of current operations against operations
previously identified as standard. A tool called AirTrajectoryMiner is
presented, aiming at monitoring the instantaneous health of the airspace, in
real time. The airspace is "healthy" when all aircraft are flying according to
the nominal procedures. A measure of complexity is introduced, measuring the
conformance of current flight to nominal flight patterns. When an aircraft does
not conform, the complexity increases as more attention from ATC is required to
ensure a safe separation between aircraft.Comment: 15 pages, 20 figure
NASA-ONERA Collaboration on Human Factors in Aviation Accidents and Incidents
This is the first annual report jointly prepared by NASA and ONERA on the work performed under the agreement to collaborate on a study of the human factors entailed in aviation accidents and incidents, particularly focused on the consequences of decreases in human performance associated with fatigue. The objective of this agreement is to generate reliable, automated procedures that improve understanding of the levels and characteristics of flight-crew fatigue factors whose confluence will likely result in unacceptable crew performance. This study entails the analyses of numerical and textual data collected during operational flights. NASA and ONERA are collaborating on the development and assessment of automated capabilities for extracting operationally significant information from very large, diverse (textual and numerical) databases; much larger than can be handled practically by human experts
First Annual Report: NASA-ONERA Collaboration on Human Factors in Aviation Accidents and Incidents
This is the first annual report jointly prepared by NASA and ONERA on the work performed under the agreement to collaborate on a study of the human factors entailed in aviation accidents and incidents particularly focused on consequences of decreases in human performance associated with fatigue. The objective of this Agreement is to generate reliable, automated procedures that improve understanding of the levels and characteristics of flight-crew fatigue factors whose confluence will likely result in unacceptable crew performance. This study entails the analyses of numerical and textual data collected during operational flights. NASA and ONERA are collaborating on the development and assessment of automated capabilities for extracting operationally significant information from very large, diverse (textual and numerical) databases much larger than can be handled practically by human experts. This report presents the approach that is currently expected to be used in processing and analyzing the data for identifying decrements in aircraft performance and examining their relationships to decrements in crewmember performance due to fatigue. The decisions on the approach were based on samples of both the numerical and textual data that will be collected during the four studies planned under the Human Factors Monitoring Program (HFMP). Results of preliminary analyses of these sample data are presented in this report
Artemisinin production by plant hairy root cultures in gas- and liquid-phase bioreactors
Key message
Alternative biotechnological protocol for large-scale artemisinin production was established. It featured enhanced growth and artemisinin production by cultivation of hairy roots in nutrient mist bioreactor (NMB) coupled with novel cultivation strategies.
Artemisinin is used for the treatment of cerebral malaria. Presently, its main source is from seasonal plant Artemisia annua. This study featured investigation of growth and artemisinin production by A. annua hairy roots (induced by Agrobacterium rhizogenes-mediated genetic transformation of explants) in three bioreactor configurations—bubble column reactor, NMB and modified NMB particularly to establish their suitability for commercial production. It was observed that cultivation of hairy roots in a non-stirred bubble column reactor exhibited a biomass accumulation of 5.68 g/l only while batch cultivation in a custom-made NMB exhibited a higher biomass concentration of 8.52 g/l but relatively lower artemisinin accumulation of 0.22 mg/g was observed in this reactor. A mixture of submerged liquid-phase growth (for 5 days) followed by gas-phase cultivation in nutrient mist reactor operation strategy (for next 15 days) was adopted for hairy root cultivation in this investigation. Reasonably, high (23.02 g/l) final dry weight along with the artemisinin accumulation (1.12 mg/g, equivalent to 25.78 mg/l artemisinin) was obtained in this bioreactor, which is the highest reported artemisinin yield in the gas-phase NMB cultivation
In vitro study on the nematicidal activity of entomopathogenic bacteria against the root knot nematode Meloidogyne incognita
National loss of Rs. 21,068.73 million has been estimated due to plant-parasitic nematodes in India. Among plant-parasitic nematodes, one of the major nematodes, root-knot nematodes (RKNs), are well-known diseases causing major losses in vegetable crops. An in vitro experiment was conducted to evaluate the nematicidal activities of the cell-free culture filtrate (CFCF) of entomopathogenic bacteria Photorhabdus spp. and Xenorhabdus spp. isolated from entomopathogenic nematodes Heterorhabditis indica (DH3) and Steinernema abbasi (CS-39), respectively. The applied doses were 90, 50, 25 and 10% CFCFs. The experiment was performed on the plant-parasitic nematode Meloidogyne incognita, and the % mortalities were determined at 6, 12, 24 and 48 hr intervals. The results of the present study revealed that 100% mortality was achieved after 48 hrs with a 10% filtrate of H. indica isolate DH3, while no significant result was achieved even after 48 hrs and at 90% CFCF of isolate CS39. Therefore, 10% CFCFs may be recommended for application in root-knot nematode-infected fields for the control
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