2,593 research outputs found
A magnetic induction introscope for flaw detection of metal objects
An apparatus for obtaining two-dimensional images of sheet-metal products that is based on a scanning matrix of spiral induction coils has been designed. It was experimentally shown that it is possible to detect flaws and objects that are hidden behind metallic barriers. The scanning area was 37 × 32 cm and the measurement step was 5 mm. Special treatment allows one to restore the distribution of induction currents in conductive objects from the remote measurement of the normal-component distribution of the magnetic induction vector on a plane
Fuzzy interpretation for temporal-difference learning in anomaly detection problems
Nowadays, information control systems based on databases develop dynamically worldwide. These systems are extensively implemented
into dispatching control systems for railways, intrusion detection systems for computer security and other domains centered on big data
analysis. Here, one of the main tasks is the detection and prediction of temporal anomalies, which could be a signal leading to significant (and often critical) actionable information. This paper proposes the new anomaly prevent detection technique, which allows for determining the predictive temporal structures. Presented approach is based on a hybridization of stochastic Markov reward model by using fuzzy production rules, which allow to correct Markov information based on expert knowledge about the process dynamics as well as Markov’s intuition about the probable anomaly occurring. The paper provides experiments showing the efficacy of detection and prediction. In addition, the analogy between new framework and temporal-difference learning for sequence anomaly detection is graphically illustrated.Web of Science64363262
Analytical device model for graphene bilayer field-effect transistors using weak nonlocality approximation
We develop an analytical device model for graphene bilayer field-effect
transistors (GBL-FETs) with the back and top gates. The model is based on the
Boltzmann equation for the electron transport and the Poisson equation in the
weak nonlocality approximation for the potential in the GBL-FET channel. The
potential distributions in the GBL-FET channel are found analytically. The
source-drain current in GBL-FETs and their transconductance are expressed in
terms of the geometrical parameters and applied voltages by analytical formulas
in the most important limiting cases. These formulas explicitly account for the
short-gate effect and the effect of drain-induced barrier lowering. The
parameters characterizing the strength of these effects are derived. It is
shown that the GBL-FET transconductance exhibits a pronounced maximum as a
function of the top-gate voltage swing. The interplay of the short-gate effect
and the electron collisions results in a nonmonotonic dependence of the
transconductance on the top-gate length.Comment: 12 pages, 7 figure
Hyperbolic Topological Invariants and the Black Hole Geometry
We discuss the isometry group structure of three-dimensional black holes and
Chern-Simons invariants. Aspects of the holographic principle relevant to black
hole geometry are analyzed.Comment: 11 pages, AMSTeX, Contribution to the Fifth Alexander Friedmann
International Seminar on Gravitation and Cosmolog
Anisotropic Topological Hall Effect with Real and Momentum Space Berry Curvature in the Antiskrymion Hosting Heusler Compound MnPtSn
The topological Hall effect (THE) is one of the key signatures of
topologically non-trivial magnetic spin textures, wherein electrons feel an
additional transverse voltage to the applied current. The magnitude of THE is
often small compared to the anomalous Hall effect. Here, we find a large THE of
0.9 cm that is of the same order of the anomalous Hall effect in the
single crystalline antiskyrmion hosting Heusler compound MnPtSn, a
non-centrosymmetric tetragonal compound. The THE is highly anisotropic and
survives in the whole temperature range where the spin structure is noncoplanar
(<170 K). The THE is zero above the spin reorientation transition temperature
of 170 K, where the magnetization will have a collinear and ferromagnetic
alignment. The large value of the THE entails a significant contribution from
the momentum space Berry curvature along with real space Berry curvature, which
has never been observed earlier
Temperature operating mode of the CuBr+Ne+H2(HBr)-laser at change of pumping
The analysis of a temperature mode of the laser on copper bromide vapour using active additives of hydrogen (bromhydrogen) at change of pumping parameters has been carried out. It is shown that introduction of the optimal additive increases the discharge tube wall temperature from 620 up to 720 °С. The increase of wall temperature 50...60 °С more can occur at change of buffer gas pressure from 3,3 to 13,3 kPa, as well as at increase working capacity twice. It is stated that introduction of the additive raises pressure of working substance vapours in the active media of the laser of average diameter 6,7 Pa more due to interaction of bromine, bromhydrogen with copper atoms settled on the tube wall. The peculiarities of laser thermal mode at high frequencies of pulse sequences (up to 100 kHz) have been considered
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