456 research outputs found
Optical properties of aerosols and clouds: The software package OPAC
The software package OPAC (Optical Properties of Aerosols and Clouds) is described. It easily provides optical properties in the solar and terrestrial spectral range of atmospheric particulate matter. Microphysical and optical properties of six water clouds, three ice clouds, and 10 aerosol components, which are considered as typical cases, are stored as ASCII files. The optical properties are the extinction, scattering, and absorption coefficients, the single scattering albedo, the asymmetry parameter, and the phase function. They are calculated on the basis of the microphysical data (size distribution and spectral refractive index) under the assumption of spherical particles in case of aerosols and cloud droplets and assuming hexagonal columns in case of cirrus clouds. Data are given for up to 61 wavelengths between 0.25 and 40 mu m and up to eight values of the relative humidity. The software package also allows calculation of derived optical properties like mass extinction coefficients and Angstrom coefficients. Real aerosol in the atmosphere always is a mixture of different components. Thus, in OPAC it is made possible to get optical properties of any mixtures of the basic components and to calculate optical depths on the base of exponential aerosol height profiles. Typical mixtures of aerosol components as well as typical height profiles are proposed as default values, but mixtures and profiles for the description of individual cases may also be achieved simply
Free-flight measurements of the rolling effectiveness and drag of trailing-edge spoilers on a tapered sweptback wing at Mach numbers 0.6 and 1.4
Free-flight measurements of some effects of spoiler span and projection and wing flexibility on rolling effectiveness and drag of plain spoilers on a tapered sweptback wing at Mach numbers between 0.6 and 1.6
Rational imitation for robots: the cost difference model
© 2017, © The Author(s) 2017. Infants imitate behaviour flexibly. Depending on the circumstances, they copy both actions and their effects or only reproduce the demonstrator’s intended goals. In view of this selective imitation, infants have been called rational imitators. The ability to selectively and adaptively imitate behaviour would be a beneficial capacity for robots. Indeed, selecting what to imitate is an outstanding unsolved problem in the field of robotic imitation. In this paper, we first present a formalized model of rational imitation suited for robotic applications. Next, we test and demonstrate it using two humanoid robots
Free-flight Investigation at Transonic and Supersonic Speeds of the Rolling Effectiveness of a Partial-span Aileron on an Inversely Tapered Sweptback Wing
Free-flight Measurements of Some Effects of Aileron Span, Chord, and Deflection and of Wing Flexibility on the Rolling Effectiveness of Ailerons on Sweptback Wings at Mach Numbers Between 0.8 and 1.6
Some effects of spanwise aileron location and wing structural rigidity on the rolling effectiveness of 0.3-chord flap-type ailerons on a tapered wing having 63 degrees sweepback at the leading edge and NACA 64A005 airfoil sections
Weakly nonlinear quantum transport: an exactly solvable model
We have studied the weakly non-linear quantum transport properties of a
two-dimensional quantum wire which can be solved exactly. The non-linear
transport coefficients have been calculated and interesting physical properties
revealed. In particular we found that as the incoming electron energy
approaches a resonant point given by energy , where the transport is
characterized by a complete reflection, the second order non-linear conductance
changes its sign. This has interesting implications to the current-voltage
characteristics. We have also investigated the establishment of the gauge
invariance condition. We found that for systems with a finite scattering
region, correction terms to the theoretical formalism are needed to preserve
the gauge invariance. These corrections were derived analytically for this
model.Comment: 15 pages, LaTeX, submitted to Phys. Rev.
Collection and Summary of Flap-type-aileron Rolling-effectiveness Data at Zero Lift as Determined by Rocket-powered Model Tests at Mach Numbers Between 0.6 and 1.6
Evaluating Local Community Methods in Networks
We present a new benchmarking procedure that is unambiguous and specific to
local community-finding methods, allowing one to compare the accuracy of
various methods. We apply this to new and existing algorithms. A simple class
of synthetic benchmark networks is also developed, capable of testing
properties specific to these local methods.Comment: 8 pages, 9 figures, code included with sourc
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