152 research outputs found
Fixed versus random triangulations in 2D simplicial Regge calculus
We study 2D quantum gravity on spherical topologies using the Regge calculus
approach with the measure. Instead of a fixed non-regular triangulation
which has been used before, we study for each system size four different random
triangulations, which are obtained according to the standard Voronoi-Delaunay
procedure. We compare both approaches quantitatively and show that the
difference in the expectation value of between the fixed and the random
triangulation depends on the lattice size and the surface area . We also try
again to measure the string susceptibility exponents through a finite-size
scaling Ansatz in the expectation value of an added interaction term in
an approach where is held fixed. The string susceptibility exponent
is shown to agree with theoretical predictions for the sphere,
whereas the estimate for appears to be too negative.Comment: 4 latex pages + 4 ps-figs. + espcrc2.sty, poster presented by W.
Janke at LATTICE96(gravity
Simplicial Quantum Gravity on a Randomly Triangulated Sphere
We study 2D quantum gravity on spherical topologies employing the Regge
calculus approach with the dl/l measure. Instead of the normally used fixed
non-regular triangulation we study random triangulations which are generated by
the standard Voronoi-Delaunay procedure. For each system size we average the
results over four different realizations of the random lattices. We compare
both types of triangulations quantitatively and investigate how the difference
in the expectation value of the squared curvature, , for fixed and random
triangulations depends on the lattice size and the surface area A. We try to
measure the string susceptibility exponents through finite-size scaling
analyses of the expectation value of an added -interaction term, using two
conceptually quite different procedures. The approach, where an ultraviolet
cut-off is held fixed in the scaling limit, is found to be plagued with
inconsistencies, as has already previously been pointed out by us. In a
conceptually different approach, where the area A is held fixed, these problems
are not present. We find the string susceptibility exponent in
rough agreement with theoretical predictions for the sphere, whereas the
estimate for appears to be too negative. However, our results
are hampered by the presence of severe finite-size corrections to scaling,
which lead to systematic uncertainties well above our statistical errors. We
feel that the present methods of estimating the string susceptibilities by
finite-size scaling studies are not accurate enough to serve as testing grounds
to decide about a success or failure of quantum Regge calculus.Comment: LaTex, 29 pages, including 9 figure
Developing Career Pathways in UAS for Non-Traditional Students through Collaborative, Online Learning Environments
The integration of drone technologies through online simulation platforms and uncrewed system scenarios offer opportunities to introduce STEM concepts from the fields of robotics, computer science, mechatronics, and aviation. New software technology developments will increase student engagement in STEM education and support learning of uncrewed systems applications and operating competencies. The use of drone simulation software creates a collaborative environment for group activities and sharing of results with peer review
Standardization Roadmap for Unmanned Aircraft Systems, Version 1.0
This Standardization Roadmap for Unmanned Aircraft Systems, Version 1.0 (“roadmap”) represents the culmination of the UASSC’s work to identify existing standards and standards in development, assess gaps, and make recommendations for priority areas where there is a perceived need for additional standardization and/or pre-standardization R&D.
The roadmap has examined 64 issue areas, identified a total of 60 gaps and corresponding recommendations across the topical areas of airworthiness; flight operations (both general concerns and application-specific ones including critical infrastructure inspections, commercial services, and public safety operations); and personnel training, qualifications, and certification. Of that total, 40 gaps/recommendations have been identified as high priority, 17 as medium priority, and 3 as low priority. A “gap” means no published standard or specification exists that covers the particular issue in question. In 36 cases, additional R&D is needed.
The hope is that the roadmap will be broadly adopted by the standards community and that it will facilitate a more coherent and coordinated approach to the future development of standards for UAS. To that end, it is envisioned that the roadmap will be widely promoted and discussed over the course of the coming year, to assess progress on its implementation and to identify emerging issues that require further elaboration
Measure dependence of 2D simplicial quantum gravity
We study pure 2D Euclidean quantum gravity with interaction on
spherical lattices, employing Regge's formulation. We attempt to measure the
string susceptibility exponent by using a finite-size
scaling Ansatz in the expectation value of . To check on effects of the
path integral measure we investigate two scale invariant measures, the
"computer" measure and the Misner measure .Comment: 3 pages, self unpacking uuencoded PostScript file, contribution to
LATTICE9
Using Small UAS for STEM Education: Introducing Robotics and Mechatronics with Drones
Several global developments point to importance of STEM-related education and studies. Every industry sector faces challenges in the recruiting of qualified personnel, due to retiring employees and general economic growth. Also, several domains, foremost automotive and aviation are undergoing a tremendous shift towards electrification to achieve sustainability. Hence, sparking the interest in STEM studies, education and vocational training cannot start early enough. This paper introduces the benefits of the educational use of sUAS by identifying core benefits in the three domains of learning – cognitive, affective, psycho-motor. Preliminary data and survey results from from several science, technology, engineering and math (STEM) drone providers worldwide will be used to identify and underline the benefits of this educational concepts
The critical behaviour of Ising spins on 2D Regge lattices
We performed a high statistics simulation of Ising spins coupled to 2D
quantum gravity on toroidal geometries. The tori were triangulated using the
Regge calculus approach and contained up to vertices. We used a
constant area ensemble with an added interaction term, employing the
measure. We find clear evidence that the critical exponents of the Ising
phase transition are consistent with the static critical exponents and do not
depend on the coupling strength of the interaction term. We definitively
can exclude for this type of model a behaviour as predicted by Boulatov and
Kazakov [Phys. Lett. {\bf B186}, 379 (1987)] for Ising spins coupled to
dynamically triangulated surfaces.Comment: 15 pages with 3 figures in form of an uudecoded compressed
tar-ps-file. FUB-HEP 06/9
COVID-19 Testing Unit Munich: Impact of Public Health and Safety Measures on Patient Characteristics and Test Results, January to September 2020
To assess the course of the COVID-19 pandemic and the impact of non-pharmaceutical interventions, the number of reported positive test results is frequently used as an estimate of the true number of population-wide infections. We conducted a retrospective observational analysis of patient data of the Corona Testing Unit (CTU) in Munich, Bavaria, Germany between January 27th, and September 30th, 2020. We analyzed the course of daily patient numbers over time by fitting a negative binomial model with multiple breakpoints. Additionally, we investigated possible influencing factors on patient numbers and characteristics by literature review of policy papers and key informant interviews with individuals involved in the set-up of the CTU. The 3,963 patients included were mostly young (median age: 34, interquartile range: 27–48), female (66.2%), and working in the healthcare sector (77%). For these, 5,314 real-time RT-PCR tests were conducted with 157 (2.94%) positive results. The overall curve of daily tests and positive results fits the re-ported state-wide incidence in large parts but shows multiple breakpoints with considerable trend changes. These can be most fittingly attributed to testing capacities and -strategies and individual risk behavior, rather than public health measures. With the large impact on patient numbers and pre-test probabilities of various strategic and operational factors, we consider the derived re-ported incidence as a poor measurement to base policy decisions on. Testing units should be prepared to encounter these fluctuations with a quickly adaptable structure
Viral Theatres’ Pandemic Playbook - Documenting German theatre during COVID-19
This document offers an overview of the artistic research project Viral Theatres, which documents the radical changes in theatre aesthetics and infrastructure during the Covid-19 pandemic by building an online multimedia living archive that tracks these developments in interviews, video documentaries, rehearsal residencies, and case studies. Through a survey of five exemplary case studies we show how significantly the tools and practices of theatre have shifted during the pandemic and suggest that these examples belong to a reconceptualization of the idea of theatre per se. In creating an online Living Archive platform that makes these and other case studies and pandemic material accessible, Viral Theatres contributes to creative documentation of pandemic culture
Finite-Size Scaling Study of the Three-Dimensional Classical Heisenberg Model
We use the single-cluster Monte Carlo update algorithm to simulate the
three-dimensional classical Heisenberg model in the critical region on simple
cubic lattices of size with , and . By
means of finite-size scaling analyses we compute high-precision estimates of
the critical temperature and the critical exponents, using extensively
histogram reweighting and optimization techniques. Measurements of the
autocorrelation time show the expected reduction of critical slowing down at
the phase transition. This allows simulations on significantly larger lattices
than in previous studies and consequently a better control over systematic
errors in finite-size scaling analyses.Comment: 9 pages, FUB-HEP 9/92, HLRZ Preprint 56/92, August 199
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