162,395 research outputs found
Optimal mass distribution for passivity-based bipedal robots
No full textThis paper reports how and to what extent the mass distribution of a passive dynamic walker can be tuned to maximize walking speed and stability. An exploration of the complete parameter space of a bipedal walker is performed by numerical optimization, and optimal manifolds are found in terms of speed, the form of which can be explained by a physical analysis of step periods. Stability, quantified by the minimal basin of attraction, is also shown to be high along these manifolds, but with a maximum at only moderate speeds. Furthermore, it is examined how speed and stability change on different ground slopes. The observed dependence of the stability measure oil the slope is consistent with the interpretation of the walking cycle as a feedback loop, which also provides an explanation for the destabilization of the gait at higher slopes. Regarding speed, an unexpected decrease at higher slopes is observed. This effect reveals another important feature of passive dynamic walking, a swing-back phase of the swing leg near the end of a step, which decreases walking speed on the one hand, but seems to be crucial for the stability of the gait on the other hand. In conclusion, maximal robustness and highest walking speed are shown to be partly conflicting objectives of optimization
Rekombinante Genproben in der Diagnostik der familiären Hypercholesterinämie
No full textGeisel J, Oette K, Weisshaar B. Rekombinante Genproben in der Diagnostik der familiären Hypercholesterinämie. Der Kassenarzt. 1990;30(7):51-54
Statistics of extreme waves in random media
No full textWaves traveling through random media exhibit random focusing that leads to extremely high wave intensities even in the absence of nonlinearities. Although such extreme events are present in a wide variety of physical systems and the statistics of the highest waves is important for their analysis and forecast, it remains poorly understood, in particular, in the regime where the waves are highest. We suggest a new approach that greatly simplifies the mathematical analysis and calculate the scaling and the distribution of the highest waves valid for a wide range of parameters
Universal Statistics of Branched Flows
No full textEven very weak correlated disorder potentials can cause extreme fluctuations in Hamiltonian flows. In two dimensions this leads to a pronounced branching of the flow. Although present in a great variety of physical systems, a quantitative theory of the branching statistics is lacking. Here, we derive an analytical expression for the number of branches valid for all distances from a source. We also derive the scaling relations that make this expression universal for a wide range of random potentials. Our theory has possible applications in many fields ranging from semiconductor to geophysics
[Report to Chief J. E. Curry, by an unknown author #1]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
[Report to Chief J. E. Curry, by an unknown author #2]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
Improved detection of familial defective apolipoprotein B-100 by restriction-site-introducing polymerase chain reaction
No full textGeisel J, Schleifenbaum T, Weisshaar B, Oette K. Improved detection of familial defective apolipoprotein B-100 by restriction-site-introducing polymerase chain reaction. Clinical Chemistry. 1993;39(9):2026-2027
Intensity fluctuations of waves in random media: What is the semiclassical limit?
No full textWaves traveling through weakly random media are known to be strongly affected by their corresponding ray dynamics, in particular in forming linear freak waves. The ray intensity distribution, which, e.g., quantifies the probability of freak waves is unknown, however, and a theory of how it is approached in an appropriate semiclassical limit of wave mechanics is lacking. We show that this limit is not the usual limit of small wavelengths, but that of decoherence. Our theory, which can describe the intensity distribution for an arbitrary degree of coherence is relevant to a wide range of physical systems, as decoherence is omnipresent in real systems
Diagnosis of Familial Hypercholesterolemia using DNA probes for the Low-density Lipoprotein Receptor gene
No full textGeisel J, Oette K, Weisshaar B. Diagnosis of Familial Hypercholesterolemia using DNA probes for the Low-density Lipoprotein Receptor gene. In: Henke J, Kömpf J, Driesel AJ, eds. DNA-Polymorphism in Forensic and Medicine. BioTechForum. Vol 1. Heidelberg: Hüthig; 1990: 31-46
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