1,182 research outputs found
RAFCON: a Graphical Tool for Task Programming and Mission Control
There are many application fields for robotic systems including service
robotics, search and rescue missions, industry and space robotics. As the
scenarios in these areas grow more and more complex, there is a high demand for
powerful tools to efficiently program heterogeneous robotic systems. Therefore,
we created RAFCON, a graphical tool to develop robotic tasks and to be used for
mission control by remotely monitoring the execution of the tasks. To define
the tasks, we use state machines which support hierarchies and concurrency.
Together with a library concept, even complex scenarios can be handled
gracefully. RAFCON supports sophisticated debugging functionality and tightly
integrates error handling and recovery mechanisms. A GUI with a powerful state
machine editor makes intuitive, visual programming and fast prototyping
possible. We demonstrated the capabilities of our tool in the SpaceBotCamp
national robotic competition, in which our mobile robot solved all exploration
and assembly challenges fully autonomously. It is therefore also a promising
tool for various RoboCup leagues.Comment: 8 pages, 5 figure
The effect of classical noise on a quantum two-level system
We consider a quantum two-level system perturbed by classical noise. The
noise is implemented as a stationary diffusion process in the off-diagonal
matrix elements of the Hamiltonian, representing a transverse magnetic field.
We determine the invariant measure of the system and prove its uniqueness. In
the case of Ornstein-Uhlenbeck noise, we determine the speed of convergence to
the invariant measure. Finally, we determine an approximate one-dimensional
diffusion equation for the transition probabilities. The proofs use both
spectral-theoretic and probabilistic methods.Comment: 25 page
Transmembrane anion transport mediated by halogen-bond donors
In biology and chemistry, the transport of anions across lipid bilayer membranes is usually achieved by sophisticated supramolecular architectures. Significant size reduction of transporters is hampered by the intrinsically hydrophilic nature of typical anion-binding functionalities, hydrogen-bond donors or cations. To maximize the atom efficiency of anion transport, the hydrophobic nature, directionality, and strength of halogen bonds seem promising. Unlike the ubiquitous, structurally similar hydrogen bonds, halogen bonds have not been explored for anion transport. Here we report that transport across lipid bilayers can be achieved with small perfluorinated molecules that are equipped with strong halogen-bond donors. Transport is observed with trifluoroiodomethane (boiling point=â22 °C); that is, it acts as a 'single-carbon' transporter. Contrary to the destructive action of small-molecule detergents, transport with halogen bonds is leakage-free, cooperative, non-ohmic and highly selective, with anion/cation permeability ratios <37
Credit bureaus between risk-management, creditworthiness assessment and prudential supervision
"This text may be downloaded for personal research purposes only. Any additional reproduction for other purposes, whether in hard copy or electronically, requires the consent of the author. If cited or quoted, reference should be made to the full name of the author, the title, the working paper or other series, the year, and the publisher."This paper discusses the role and operations of consumer Credit Bureaus in the European Union in the context of the economic theories, policies and law within which they work. Across Europe there is no common practice of sharing the credit data of consumers which can be used for several purposes. Mostly, they are used by the lending industry as a practice of creditworthiness assessment or as a risk-management tool to underwrite borrowing decisions or price risk. However, the type, breath, and depth of information differ greatly from country to country. In some Member States, consumer data are part of a broader information centralisation system for the prudential supervision of banks and the financial system as a whole. Despite EU rules on credit to consumers for the creation of the internal market, the underlying consumer data infrastructure remains fragmented at national level, failing to achieve univocal, common, or defined policy objectives under a harmonised legal framework. Likewise, the establishment of the Banking Union and the prudential supervision of the Euro area demand standardisation and convergence of the data used to measure debt levels, arrears, and delinquencies. The many functions and usages of credit data suggest that the policy goals to be achieved should inform the legal and institutional framework of Credit Bureaus, as well as the design and use of the databases. This is also because fundamental rights and consumer protection concerns arise from the sharing of credit data and their expanding use
What matters more for South African householdsâ debt repayment difficulties?
While the increased access to consumer credit has helped many families improve their welfare, the rising repayment burdens upon a background of chronically law savings rate have generated concerns that South African families are becoming ever more financially fragile and less able to meet their consumer debt repayment obligations. Using data from the Cape Area Panel Study (CAPS), this paper investigates whether consumer debt repayment problems are better explained by excessive spending which leaves households financial overstretched or by negative income shocks. The results indicate that households are significantly more likely to be delinquent on their financial obligations when they suffer negative events beyond their control rather than due to the size of the expenditure burden. This suggests that some consumers will experience repayment problems even when they borrow within their means. Thus regulatory efforts to improve mechanisms for debt relief might be more meaningful than restrictions on lending
Measuring Gravito-magnetic Effects by Multi Ring-Laser Gyroscope
We propose an under-ground experiment to detect the general relativistic
effects due to the curvature of space-time around the Earth (de Sitter effect)
and to rotation of the planet (dragging of the inertial frames or
Lense-Thirring effect). It is based on the comparison between the IERS value of
the Earth rotation vector and corresponding measurements obtained by a
tri-axial laser detector of rotation. The proposed detector consists of six
large ring-lasers arranged along three orthogonal axes.
In about two years of data taking, the 1% sensitivity required for the
measurement of the Lense-Thirring drag can be reached with square rings of 6
side, assuming a shot noise limited sensitivity ().
The multi-gyros system, composed of rings whose planes are perpendicular to one
or the other of three orthogonal axes, can be built in several ways. Here, we
consider cubic and octahedron structures. The symmetries of the proposed
configurations provide mathematical relations that can be used to study the
stability of the scale factors, the relative orientations or the ring-laser
planes, very important to get rid of systematics in long-term measurements,
which are required in order to determine the relativistic effects.Comment: 24 pages, 26 Postscript figure
Prototype ATLAS IBL Modules using the FE-I4A Front-End Readout Chip
The ATLAS Collaboration will upgrade its semiconductor pixel tracking
detector with a new Insertable B-layer (IBL) between the existing pixel
detector and the vacuum pipe of the Large Hadron Collider. The extreme
operating conditions at this location have necessitated the development of new
radiation hard pixel sensor technologies and a new front-end readout chip,
called the FE-I4. Planar pixel sensors and 3D pixel sensors have been
investigated to equip this new pixel layer, and prototype modules using the
FE-I4A have been fabricated and characterized using 120 GeV pions at the CERN
SPS and 4 GeV positrons at DESY, before and after module irradiation. Beam test
results are presented, including charge collection efficiency, tracking
efficiency and charge sharing.Comment: 45 pages, 30 figures, submitted to JINS
- âŠ