This paper presents the state of the current activities to develop a high-speed inspection system for evaluating rail defects. Since conventional contact ultrasonic techniques are speed limited, the aim was to build an automatic inspection system, which applies non-contact ultrasonic methods. An automatic Laser Ultrasonic system for Rail Inspection (LURI) has been developed and tested on a rail...

AC bridge techniques commonly used for precision impedance measurements have been adapted to develop an eddy current sensor for rail defect detection. By using two detection coils instead of just one as in a conventional sensor, we can balance out the large baseline signals corresponding to a normal rail. We have significantly enhanced the detection sensitivity of the eddy current method by det...

Early detection of defects inside a rail is great significance to ensure the safety transit. This work investigated ability ultrasonic guided waves (UGWs) detect internal in head. First, model UGW propagation rail, which has an irregular cross-section, was constructed based on semi-analytical finite element (SAFE) method. Fundamental characteristics, such as wavenumber, phase or group velocity,...

Abstract A singular rail or wheel surface irregularity, such as a squat, insulation joint flat, can cause large wheel-rail impact force. Both the magnitude and frequency content of force need to be correctly modelled because they are closely related formation, deterioration detection irregularities. In this paper, we compare two types commonly used wheel-track interaction models for problems, i...

In a classification problem, hard margin SVMs tend to minimize the generalization error by maximizing the margin. Regularization is obtained with soft margin SVMs which improve performances by relaxing the constraints on the margin maximization. This article shows that comparable performances can be obtained in the linearly separable case with the Ho–Kashyap learning rule associated to early st...

Recent in situ observations during Critical Ionization Velocity (CIV) experiments under the CRIT project produced puzzling results, apparently at odds with current ClV theories. It is shown that incorporation in the theory of lower hybrid wave (LHW) instabilities of strong turbulence and finite size effects results in reconciliation of the theory with the observations.

In a classification problem, hard margin SVMs tend to minimize the generalization error by maximizing the margin. Regularization is obtained with soft margin SVMs which improve performances by relaxing the constraints on the margin maximization. This article shows that comparable performances can be obtained in the linearly separable case with the Ho–Kashyap learning rule associated to early st...