1,332 research outputs found
Quantization of the Superparticle on
We analyze superparticle dynamics on the coset . The system is quantized in
canonical coordinates obtained by gauge invariant Hamiltonian reduction. The
left and right Noether charges of a massive particle are parametrized by
coadjoint orbits of a timelike element of . Each chiral sector
is described by two bosonic and two fermionic canonical coordinates
corresponding to a superparticle with superpotential , where is
the particle mass. Canonical quantization then provides a quantum realization
of . For the massless particle the chiral
charges lie on the coadjoint orbit of a nilpotent element of
and each of them depends only on one real fermion, which demonstrates the
underlying -symmetry. These remaining left and right fermionic
variables form a canonical pair and the system is described by four bosonic and
two fermionic canonical coordinates. Due to conformal invariance of the
massless particle, the extends to the
corresponding superconformal algebra . Its 19 charges are
given by all real quadratic combinations of the canonical coordinates, which
trivializes their quantization.Comment: 25+1 pages; v2: minor changes, references added and updated; v3:
minor changes, one reference added, matches published versio
Asymmetric Properties of Heart Rate Variability to Assess Operator Fatigue
The aim of this study is to evaluate the suitability of heart rate recordings for establishing a reliable connection to well-defined fatigue and performance measures in order to estimate fatigue in industrial and transportation applications. An overnight driving simulation scenario with partial sleep deprivation was utilized to induce strong fatigue. An experiment trial was divided into repeated sessions, each of which consisted of a driving performance and two vigilance tasks. Heart rate (HR) was recorded over the entire experiment; HRmeasures were derived and correlated against measures that were established from driving and vigilance task performance and that represent various aspects of operator fatigue. In a previous report (Hefner et al. 2009) we presented on the basis of the data of one volunteer that multiple fatigue measures correlate well with different expressions of heart rate variability (HRV), especially with longterm HRV derived from Poincaré plots. In this work, we intensify the Poincaré analysis by dividing the distribution of HR data in different accelerating and decelerating segments and by establishing properties of asymmetry between these segments. We also show that most of the properties of long-term HRV correlate well with specific fatigue measures for a group of 5 volunteers despite their large inter-individual differences in HR-to-fatigue correlations
Development and Preliminary Validation of the Scale for Evaluation of Psychiatric Integrative and Continuous CareâPatientâs Version
This pilot study aimed to evaluate and examine an instrument that integrates
relevant aspects of cross-sectoral (in- and outpatients) mental health care,
is simply to use and shows satisfactory psychometric properties. The
development of the scale comprised literature research, held 14 focus groups
and 12 interviews with patients and health care providers, item-pool
generation, content validation by a scientific expert panel, and face
validation by 90 patients. The preliminary scale was tested on 385 patients
across seven German hospitals with cross-sectoral mental health care (CSMHC)
as part of their treatment program. Psychometric properties of the scale were
evaluated using genuine and transformed data scoring. To check reliability and
postdictive validity of the scale, Cronbachâs α coefficient and multivariable
linear regression were used. This development process led to the development
of an 18-item scale called the âScale for Evaluation of Psychiatric
Integrative and Continuous Care (SEPICC)â with a two-point and five-point
response options. The scale consists of two sections. The first section
assesses the presence or absence of patientsâ experiences with various CSMHCâ
relevant components such as home treatment, flexibility of treatmentsâ
switching, case management, continuity of care, cross-sectoral therapeutic
groups, and multidisciplinary teams. The second section evaluates the
patientsâ opinions about these relevant components. Using raw and transformed
scoring resulted into comparable results. However, data distribution using
transformed scoring showed a smaller deviation from normality. For the overall
scale, the Cronbachâs α coefficient was 0.82. Self-reported experiences with
relevant components of the CSMHC were positively associated with the patients
approval of these components. In conclusion, the new scale provides a good
starting point for further validation. It can be used as a tool to evaluate
CSMHC. Methodologically, using transformed data scoring appeared to be
preferable because of a smaller deviation from normality and a higher
reliability measured by Cronbachâs α
A Robustness Analysis of a Preliminary Design of a CESTOL Aircraft
Als Teil des Sonderforschungsbereichs 880 werden AktivitĂ€ten im Flugzeugvorentwurf fĂŒr eine neue Klasse von lĂ€rmarmen leistungsfĂ€higen Transportflugzeugen mit den FĂ€higkeiten von Kurzstart und -landung (CESTOL) durchgefĂŒhrt. Ein entsprechendes Flugzeug stellt sich wegen des Einsatzes aktiver Hochauftriebssysteme völlig anders dar als ein Verkehrsflugzeug auf dem Stand aktueller Technik. Der Umstand, dass neue Technologien noch nicht genĂŒgend verstanden werden, in Kombination mit der Annahme ĂŒblicher Entwurfsdaten und der Verwendung klassischer Berechnungsmethoden, Ă€ussert sich in Unsicherheiten epistemischen Charakters. Die Robustheit eines deterministischen CESTOL Flugzeugentwurfs gegenĂŒber Parametern wie dem notwendigen Schub, den direkten Betriebskosten oder den Start- und LandebahnlĂ€ngen wird hier im Hinblick auf die genannten Unsicherheiten untersucht. Zu diesem Zweck wird eine stochastische Beschreibung von Entwurfsparametervariationen formuliert. Stochastische GröĂen zur Beurteilung der Robustheit werden ĂŒber eine Monte-Carlo-Simulation bestimmt. Eine verteilte komponentenbasierte Software-Implementierung wird zur DurchfĂŒhrung der Monte-Carlo-Simulation herangezogen. Das Softwaresystem ist auf einem Linux-Cluster mit mehreren Multi-CPU-Rechnern installiert; eine deterministische Stichprobe wird durch das Entwurfsprogramm PrADO simuliert.As part of the Collaborative Research Center 880 preliminary aircraft design activities are carried out for a new class of low-noise cruise-efficient transport aircrafts with short take-off and landing capabilities (CESTOL). A corresponding aircraft is quite different from a state-of-the-art commercial aircraft because of the use of active high-lift devices. The fact that new technologies are not sufficiently understood yet in combination with the assumption of common design data and the use of classical calculation methods expresses itself in uncertainties which are of epistemic character. The robustness of a deterministic CESTOL aircraft design towards parameters such as the necessary engine thrust, direct operating costs, or the runway lengths is investigated here concerning the mentioned uncertainties. For this purpose a stochastic description of parameter variations of the design is formulated. Stochastic quantities are computed by Monte Carlo (MC) sampling to rate the robustness. A distributed component-based software implementation is used to perform the MC sampling. The software system is installed on a Linux cluster with several multi-CPU computers; a deterministic sample is simulated through the design program PrADO
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