179 research outputs found
Development and Performance Verification of the GANDALF High-Resolution Transient Recorder System
With present-day detectors in high energy physics one often faces fast analog
pulses of a few nanoseconds length which cover large dynamic ranges. In many
experiments both amplitude and timing information have to be measured with high
accuracy. Additionally, the data rate per readout channel can reach several
MHz, which leads to high demands on the separation of pile-up pulses.
For an upgrade of the COMPASS experiment at CERN we have designed the GANDALF
transient recorder with a resolution of 12bit@1GS/s and an analog bandwidth of
500\:MHz. Signals are digitized with high precision and processed by fast
algorithms to extract pulse arrival times and amplitudes in real-time and to
generate trigger signals for the experiment. With up to 16 analog channels,
deep memories and a high data rate interface, this 6U-VME64x/VXS module is not
only a dead-time free digitization unit but also has huge numerical
capabilities provided by the implementation of a Virtex5-SXT FPGA. Fast
algorithms implemented in the FPGA may be used to disentangle possible pile-up
pulses and determine timing information from sampled pulse shapes with a time
resolution better than 50 ps.Comment: 5 pages, 9 figure
Implementation of mean-timing and subsequent logic functions on an FPGA
This article describes the implementation of a mean-timer and coincidence
logic on a Virtex-5 FPGA for trigger purposes in a particle physics experiment.
The novel feature is that the mean-timing and the coincidence logic are not
synchronized with a clock which allows for a higher resolution of approximately
400 ps, not limited by a clock frequency.Comment: 15 pages, 11 figure
Development of a 1 GS/s high-resolution transient recorder
With present-day detectors in high energy physics one is often faced with short analog pulses of a few nanoseconds length which may cover large dynamic ranges. In many experiments both amplitude and timing information have to be measured with high accuracy. Additionally, the data rate per readout channel can reach several MHz, which makes high demands on the separation of pile-up pulses. For such applications we have built the GANDALF transient recorder with a resolution of 12bit@1GS/s and an analog bandwidth of 500 MHz. Signals are digitized and processed by fast algorithms to extract pulse arrival times and amplitudes in real-time and to generate experiment trigger signals. With up to 16 analog channels, deep memories and a high data rate interface, this 6U-VME64x/VXS module is not only a dead-time free digitization unit but also has huge numerical capabilities provided by the implementation of a Virtex5-SXT FPGA. Fast algorithms implemented in the FPGA may be used to disentangle possible pile-up pulses and determine timing information from sampled pulse shapes with a time resolution in the picosecond range. Recently the application spectrum has been extended by implementing a 128-channel time-to-digital converter inside the FPGA and an appropriate input mezzanine card
Map-based Height Above Ground Estimation for Safe Operation Monitoring of Unmanned Aircraft in Very Low Level Airspaces
According to current European regulations, most common drone operations are limited to a maximum altitude of 120m above ground. However, a direct measurement of the height above ground is usually not available for small drones. Consequently, ensuring compliance to height above ground constraints may prove to be difficult for many scenarios, especially when flying over complex terrain or beyond the visual line-of-sight of a remote pilot. In this work, we investigate the use of a satellite-based navigation and digital terrain maps to estimate the height above ground. We propose to integrate this estimation into a runtime assurance architecture with a safe operation monitor ensuring compliance to the maximum height above ground imposed by regulatory or operational constraints. We assess the feasibility and limitations of the approach, by analyzing sources of errors including navigation uncertainty and elevation data accuracy. We present the design and implementation details of a height above ground estimation and monitoring system and show results from flight tests with a multicopter drone. The presented results indicate the practicability and current limitations of a map-based height above ground estimation for drones operated in very low level airspaces
Build Your Own Training Data -- Synthetic Data for Object Detection in Aerial Images
Machine learning has become one of the most widely used techniques in artificial intelligence, especially for image processing. One of the biggest challenges in developing an accurate image processing model is to collect large amounts of data that are sufficiently close to the real-world scenario. Ideally, real-world data is therefore used for model training. Unfortunately, real-world data is often insufficiently available and expensive to generate. Therefore, models are trained using synthetic data. However, there is no standardized method of how training data is generated and which properties determine the data quality. In this paper, we present first steps towards the generation of large amounts of data for human detection based on aerial images. To create labeled aerial images, we are using Unreal Engine and AirSim. We report on first impressions of the generated labeled aerial images and identify future challenges-current simulation tools can be used to create realistic and diverse images including labeling, but native support would be beneficial to ease their usage
Ensuring Safety of Machine Learning Components Using Operational Design Domain
The introduction of machine learning in the aviation domain is an ongoing process. This is also true for safety-critical domains, especially for the area of Urban Air Mobility. A significant growth in number of air taxis and an increasing level of autonomy is to be expected allowing for operating a large number of air taxis in complex urban environments. Due to the complexity of the tasks and the environment, key autonomy functions will be realized using machine learning, for example the camera-based detection of objects. However, the safety assurance for avionics systems using machine learning components is challenging. This work investigates safety and verification aspects of machine learning components. A camera-based detection of humans on the ground, e.g. to assess a potential landing area, serves as an example for an machine learning-based autonomy functio and was integrated into an Unmanned Aircraft. In the context of this exemplary machine learning component, the concept of Operational Design Domain as recently adapted European Aviation Safety Agency in the context of machine learning assurance is described along with other key concepts of machine learning assurance. Furthermore, runtime assurance is used to monitor conformance to the Operational Design Domain during flight. The presented flight test results indicate that monitoring the Operational Design Domain can support performance as well as the safety of the operation
Machine Learning Applications in Unmanned Aviation: Operational Risks and Certification Considerations
Modelling and Simulation for Aerial Refueling Automation Research for Manned and Unmanned Aircraft
Observation of a J^PC = 1-+ exotic resonance in diffractive dissociation of 190 GeV/c pi- into pi- pi- pi+
The COMPASS experiment at the CERN SPS has studied the diffractive
dissociation of negative pions into the pi- pi- pi+ final state using a 190
GeV/c pion beam hitting a lead target. A partial wave analysis has been
performed on a sample of 420000 events taken at values of the squared
4-momentum transfer t' between 0.1 and 1 GeV^2/c^2. The well-known resonances
a1(1260), a2(1320), and pi2(1670) are clearly observed. In addition, the data
show a significant natural parity exchange production of a resonance with
spin-exotic quantum numbers J^PC = 1-+ at 1.66 GeV/c^2 decaying to rho pi. The
resonant nature of this wave is evident from the mass-dependent phase
differences to the J^PC = 2-+ and 1++ waves. From a mass-dependent fit a
resonance mass of 1660 +- 10+0-64 MeV/c^2 and a width of 269+-21+42-64 MeV/c^2
is deduced.Comment: 7 page, 3 figures; version 2 gives some more details, data unchanged;
version 3 updated authors, text shortened, data unchange
Interplay among transversity induced asymmetries in hadron leptoproduction
In the fragmentation of a transversely polarized quark several left-right
asymmetries are possible for the hadrons in the jet. When only one unpolarized
hadron is selected, it exhibits an azimuthal modulation known as Collins
effect. When a pair of oppositely charged hadrons is observed, three
asymmetries can be considered, a di-hadron asymmetry and two single hadron
asymmetries. In lepton deep inelastic scattering on transversely polarized
nucleons all these asymmetries are coupled with the transversity distribution.
From the high statistics COMPASS data on oppositely charged hadron-pair
production we have investigated for the first time the dependence of these
three asymmetries on the difference of the azimuthal angles of the two hadrons.
The similarity of transversity induced single and di-hadron asymmetries is
discussed. A new analysis of the data allows to establish quantitative
relationships among them, providing for the first time strong experimental
indication that the underlying fragmentation mechanisms are all driven by a
common physical process.Comment: 6 figure
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