Using Qualitative Hypotheses to Identify Inaccurate Data

Identifying inaccurate data has long been regarded as a significant and difficult problem in AI. In this paper, we present a new method for identifying inaccurate data on the basis of qualitative correlations among related data. First, we introduce the definitions of related data and qualitative correlations among related data. Then we put forward a new concept called support coefficient function (SCF). SCF can be used to extract, represent, and calculate qualitative correlations among related data within a dataset. We propose an approach to determining dynamic shift intervals of inaccurate data, and an approach to calculating possibility of identifying inaccurate data, respectively. Both of the approaches are based on SCF. Finally we present an algorithm for identifying inaccurate data by using qualitative correlations among related data as confirmatory or disconfirmatory evidence. We have developed a practical system for interpreting infrared spectra by applying the method, and have fully tested the system against several hundred real spectra. The experimental results show that the method is significantly better than the conventional methods used in many similar systems.Comment: See http://www.jair.org/ for any accompanying file

Current-phase relation for Josephson effect through helical metal

Josephson junctions fabricated on the surface of three-dimensional topological insulators (TI) show a few unusual properties distinct from conventional Josephson junctions. In these devices, the Josephson coupling and the supercurrent are mediated by helical metal, the two-dimensional surface of the TI. A line junction of this kind is known to support Andreev bound states at zero energy for phase bias \pi, and consequently the so-called fractional ac Josephson effect. Motivated by recent experiments on TI-based Josephson junctions, here we describe a convenient algorithm to compute the bound state spectrum and the current-phase relation for junctions with finite length and width. We present analytical results for the bound state spectrum, and discuss the dependence of the current-phase relation on the length and width of the junction, the chemical potential of the helical metal, and temperature. A thorough understanding of the current-phase relation may help in designing topological superconducting qubits and manipulating Majorana fermions

Time-Distance Imaging of Solar Far-Side Active Regions

It is of great importance to monitor large solar active regions in the far-side of the Sun for space weather forecast, in particular, to predict their appearance before they rotate into our view from the solar east limb. Local helioseismology techniques, including helioseismic holography and time-distance, have successfully imaged solar far-side active regions. In this Letter, we further explore the possibility of imaging and improving the image quality of solar far-side active regions by use of time-distance helioseismology. In addition to the previously used scheme with four acoustic signal skips, a five-skip scheme is also included in this newly developed technique. The combination of both four- and five-skip far-side images significantly enhances the signal-to-noise ratio in the far-side images, and reduces spurious signals. The accuracy of the far-side active region imaging is also assessed using one whole year solar observation.Comment: 13 pages, 5 figures, accepted by ApJ Letter

A low cost air hybrid concept

This article is a pre-print version of the full and final article which is available at the link below.Copyright © 2010 Institut français du pétrole Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than IFP must be honored. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee: Request permission from Documentation, Institut français du pétrole, fax. +33 1 47 52 70 78, or [email protected] air hybrid engine absorbs the vehicle kinetic energy during braking, stores it in an air tank in the form of compressed air, and reuses it to propel a vehicle during cruising and acceleration. Capturing, storing and reusing this braking energy to give additional power can therefore improve fuel economy, particularly in cities and urban areas where the traffic conditions involve many stops and starts. In order to reuse the residual kinetic energy, the vehicle operation consists of 3 basic modes, i.e. Compression Mode (CM), Expander Mode (EM) and normal firing mode. Unlike previous works, a low cost air hybrid engine has been proposed and studied. The hybrid engine operation can be realised by means of production technologies, such as VVT and valve deactivation. In this work, systematic investigation has been carried out on the performance of the hybrid engine concept through detailed gas dynamic modelling using Ricardo WAVE software. Valve timing optimization has been done for the more efficient operation of air hybrid operation and obtaining higher braking and Motoring mean effective pressure for CM and EM respectively.EPSR

Supersymmetric massive truncations of IIb supergravity on Sasaki-Einstein manifolds

Motivated by recent interest in applications of the AdS/CFT correspondence to condensed matter applications involving fermions, we present the supersymmetric completion of the recent massive truncations of IIB supergravity on Sasaki-Einstein manifolds. In particular, we reduce the fermionic sector of IIB supergravity to obtain five dimensional N=2 supergravity coupled to one hypermultiplet and one massive vector multiplet. The supersymmetry transformations and equations of motion are presented and analyzed. Finally, a particularly interesting truncation to N=2 supergravity coupled to a single hypermultiplet is presented which is the supersymmetric completion of the recently constructed bosonic theory dual to a 3+1 dimensional system exhibiting a superconducting phase transition.Comment: v2:reference added, equations simplified, minor typos fixed; v3:matches content with prd version, minor typos correcte

NLTE study of scandium in the Sun

We investigate the formation of neutral and singly ionized scandium lines in the solar photospheres. The research is aimed derive solar $\log gf\epsilon_{\odot}$(Sc) values for scandium lines, which will later be used in differential abundance analyses of metal-poor stars. Extensive statistical equilibrium calculations were carried out for a model atom, which comprises 92 terms for \ion{Sc}{i} and 79 for \ion{Sc}{ii}. Photoionization cross-sections are assumed to be hydrogenic. Synthetic line profiles calculated from the level populations according to the NLTE departure coefficients were compared with the observed solar spectral atlas. Hyperfine structure (HFS) broadening is taken into account. The statistical equilibrium of scandium is dominated by a strong underpopulation of \ion{Sc}{i} caused by missing strong lines. It is nearly unaffected by the variation in interaction parameters and only marginally sensitive to the choice of the solar atmospheric model. Abundance determinations using the ODF model lead to a solar Sc abundance of between $\log\epsilon_\odot = 3.07$ and 3.13, depending on the choice of $f$ values. The long known difference between photospheric and meteoritic scandium abundances is confirmed for the experimental $f$-values.Comment: 10 pages, 6 figures, A&A accepte

Correction function in the Lidar equation and the solution techniques for CO2 Lidar date reduction

For lidar systems with long laser pulses the unusual behavior of the near-range signals causes serious difficulties and large errors in reduction. The commonly used lidar equation is no longer applicable since the convolution of the laser pulse with the atmospheric parameter distributions should be taken into account. It is important to give more insight into this problem and find the solution techniques. Starting from the original equation, a general form is suggested for the single scattering lidar equation where a correction function Cr is introduced. The correction Function Cr(R) derived from the original equation indicates the departure from the normal lidar equation. Examples of Cr(R) for a coaxial CO2 lidar system are presented. The Differential Absorption Lidar (DIAL) errors caused by the differences of Cr(R) for H2O measurements are plotted against height

The gain and carrier density in semiconductor lasers under steady-state and transient conditions

The carrier distribution functions in a semiconductor crystal in the presence of a strong optical field are obtained. These are used to derive expressions for the gain dependence on the carrier density and on the optical intensity-the gain suppression effect. A general expression for high-order nonlinear gain coefficients is obtained. This formalism is used to describe the carrier and power dynamics in semiconductor lasers above and below threshold in the static and transient regimes