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An Overview of Models for Response Times and Processes in Cognitive Tests.
Response times (RTs) are a natural kind of data to investigate cognitive processes underlying cognitive test performance. We give an overview of modeling approaches and of findings obtained with these approaches. Four types of models are discussed: response time models (RT as the sole dependent variable), joint models (RT together with other variables as dependent variable), local dependency models (with remaining dependencies between RT and accuracy), and response time as covariate models (RT as independent variable). The evidence from these approaches is often not very informative about the specific kind of processes (other than problem solving, information accumulation, and rapid guessing), but the findings do suggest dual processing: automated processing (e.g., knowledge retrieval) vs. controlled processing (e.g., sequential reasoning steps), and alternative explanations for the same results exist. While it seems well-possible to differentiate rapid guessing from normal problem solving (which can be based on automated or controlled processing), further decompositions of response times are rarely made, although possible based on some of model approaches
Transmittivity measurements by means of squeezed vacuum light
A method for measuring the transmittivity of optical samples by using
squeezed--vacuum radiation is illustrated. A squeezed vacuum field generated by
a below--threshold optical parametric oscillator is propagated through a
nondispersive medium and detected by a homodyne apparatus. The variance of the
detected quadrature is used for measuring the transmittivity. With this method
it is drastically reduced the number of photons passing through the sample
during the measurement interval. The results of some tests are reported.Comment: 14 pages, 8 figure
Optical Properties of the DIRC Fused Silica Cherenkov Radiator
The DIRC is a new type of Cherenkov detector that is successfully operating
as the hadronic particle identification system for the BABAR experiment at
SLAC. The fused silica bars that serve as the DIRC's Cherenkov radiators must
transmit the light over long optical pathlengths with a large number of
internal reflections. This imposes a number of stringent and novel requirements
on the bar properties. This note summarizes a large amount of R&D that was
performed both to develop specifications and production methods and to
determine whether commercially produced bars could meet the requirements. One
of the major outcomes of this R&D work is an understanding of methods to select
radiation hard and optically uniform fused silica material. Others include
measurement of the wavelength dependency of the internal reflection
coefficient, and its sensitivity to surface contaminants, development of
radiator support methods, and selection of good optical glue.Comment: 36 pages, submitted to Nuclear Instruments and Methods
The use of deforming broaching for enhancing the efficiency of cutter chisels
Purpose. To determine the potential of deforming broaching for the improvement of efficiency of cutter chisels in the mining industry.
Methodology. The study of the application of the technological process of deforming broaching was carried out based on the experimental research into conditions of assembly of press couplings corresponding to cutting rock-destroying tools, the working surface of which is reinforced with solid-alloy inserts.
Findings. Based on the conducted research, a new process of assembling the crowns of cutter chisels with the use of deforming broaching was developed.
Originality. It was determined that the range of angles of inclination of generatrix of the working cone of the deforming element and the roll-treading lip of the insert, which are necessary for efficient machining and pressing in crowns of cutters, is 4–16°. It was proven that the “solid alloy-steel” press couplings for cutter chisels will have the maximum bearing capacity at total tension a/d0 ≤ 3 %.
It was found that it is necessary to foresee the following distribution of tensions: to perform 2 % of deformation by preliminary deforming broaching, and 1 % ‒ by pressing in an insert
Practical value. The use of deforming broaching makes it possible to increase the strength of fastening the inserts of cutter chisels by 2 times, to reduce specific consumption of the tool by 4.4 times, and to increase the average drilling rate by 4 times
MARTA: A high-energy cosmic-ray detector concept with high-accuracy muon measurement
A new concept for the direct measurement of muons in air showers is
presented. The concept is based on resistive plate chambers (RPCs), which can
directly measure muons with very good space and time resolution. The muon
detector is shielded by placing it under another detector able to absorb and
measure the electromagnetic component of the showers such as a water-Cherenkov
detector, commonly used in air shower arrays. The combination of the two
detectors in a single, compact detector unit provides a unique measurement that
opens rich possibilities in the study of air showers.Comment: 11 page
The impact of correlated projections on weak lensing cluster counts
Large-scale structure projections are an obstacle in converting the shear
signal of clusters detected in weak-lensing maps into virial masses. However,
this step is not necessary for constraining cosmology with the shear-peak
abundance, if we are able to predict its amplitude. We generate a large
ensemble of N-body simulations spanning four cosmological models, with total
volume V~1 (Gpc/h)^3 per model. Variations to the matter density parameter and
amplitude of fluctuations are considered. We measure the abundance of peaks in
the mass density projected in ~100 Mpc/h slabs to determine the impact of
structures spatially correlated with the simulation clusters, identified by the
3D friends-of-friends algorithm. The halo model shows that the choice of the
smoothing filter for the density field is important in reducing the
contribution of correlated projections to individual halo masses. Such
contributions are less than 2% in the case of the optimal, compensated filter
used throughout this analysis. We measure the change in the mass of peaks when
projected in slabs of various thicknesses. Peaks in slabs of 26 Mpc/h and 102
Mpc/h suffer an average mass change of less than 2% compared to their mass in
slabs of 51 Mpc/h. We then explore the cosmology dependence of the
projected-peak mass function, and find that, for a wide range of slab
thicknesses (<500 Mpc/h), it scales with cosmology in exactly the same way as
the 3D friends-of-friends mass function and the Sheth-Tormen formula. This
extends the earlier result of Marian et al. (2009). Finally, we show that for
all cosmological models considered, the low and intermediate mass bins of the
peak abundance can be described using a modified Sheth-Tormen functional form
to within 10%-20% accuracy.Comment: 19 pages, 14 figures, accepted for publication in the Astrophysical
Journa
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