Search results for "NDT"

Des Hertzogthums Lieflands Ritter- und Land-Recht

1739

Arendt y Heidegger ante el 'diluvio de Auschwitz'

2019

Tras las Conferencias de Bremen de Martin Heidegger y, más aún, tras los escritos de Hannah Arendt, el nacionalsocialismo ha sido reinterpretado como revelador de la modernidad técnica hasta el punto de que la institución nazi de los campos de concentración y exterminio se ha visto erigida en paradigma de esta modernidad. Esta visión, que podría llamarse posmoderna, de la historia del siglo xx merece ser cuestionada.1 ¿Cómo es posible que la obra de Heidegger, ese profesor y rector nacionalsocialista a quien se le prohíbe enseñar en 1945, haya tardado tanto tiempo en ser reconocida como un caso ejemplar, dentro del campo filosófico, de la visión del mundo o Weltanschauung nacionalsocialista…

Robust Estimation for Discrete Markov System with Time-Varying Delay and Missing Measurements

2013

This paper addresses theℋ∞filtering problem for time-delayed Markov jump systems (MJSs) with intermittent measurements. Within network environment, missing measurements are taken into account, since the communication channel is supposed to be imperfect. A Bernoulli process is utilized to describe the phenomenon of the missing measurements. The original system is transformed into an input-output form consisting of two interconnected subsystems. Based on scaled small gain (SSG) theorem and proposed Lyapunov-Krasovskii functional (LKF), the scaled small gains of the subsystems are analyzed, respectively. New conditions for the existence of theℋ∞filters are established, and the correspondingℋ∞f…

A Neural Network model for the Evaluation of Text Complexity in Italian Language: a Representation Point of View

2018

Abstract The goal of a text simplification system (TS) is to create a new text suited to the characteristics of a reader, with the final goal of making it more understandable.The building of an Automatic Text Simplification System (ATS) cannot be separated from a correct evaluation of the text complexity. In fact the ATS must be capable of understanding if a text should be simplified for the target reader or not. In a previous work we have presented a model capable of classifying Italian sentences based on their complexity level. Our model is a Long Short Term Memory (LSTM) Neural Network capable of learning the features of easy-to-read and complex-to-read sentences autonomously from a anno…

BICKEL–ROSENBLATT TEST FOR WEAKLY DEPENDENT DATA

2012

The aim of this paper is to analyze the Bickel–Rosenblatt test for simple hypothesis in case of weakly dependent data. Although the test has nice theoretical properties, it is not clear how to implement it in practice. Choosing different band-width sequences first we analyze percentage rejections of the test statistic under H0 by some empirical simulation analysis. This can serve as an approximate rule for choosing the bandwidth in case of simple hypothesis for practical implementation of the test. In the recent paper [12] a version of Neyman goodness-of-fit test was established for weakly dependent data in the case of simple hypotheses. In this paper we also aim to compare and discuss the …

Visualization of EDI messages

2003

Multi-organizational EDI message networks are complicated communication environments with various standards and technologies. The role of third party message exchange hubs has become more important and their tasks more difficult. Current development activities for supporting the utilization of XML in electronic commerce focuses on message standardization and specification of common business architectures, processes, and web practices. A need to visualize EDI messages in different contexts to human readers has received insufficient attention in ongoing activities. In this paper we discuss problems and approaches related to the visualization of EDI messages in XML format. An idea of a standar…

Off-line scan path planning for robotic NDT

2018

This work presents computer-aided scan path generation for robotic non-destructive testing of complex shaped test-pieces. Off-line programmed scan path was used to robotically inspect an aluminium fixed leading edge skin panel of an aircraft wing by means of swept frequency eddy currents method. Eddy currents probe was deployed by means of a six-axis robotic arm KUKA KR5 arc. Reverse engineering of the test-piece was carried out to reconstruct CAD model of its surface. Positioning accuracy of the performed continuous scan was measured with a laser tracker in accordance with ISO 9283:1998 and is reported in the paper. The positional uncertainty of the NDT scan calculated as the standard devi…

On the Use of Two Emerging Laser-Based Flaw-Detection Techniques – Considerations and Practicalities

2023

The pursuit of non-contact techniques for detecting ultrasonic waves propagating on the surface of solids is stimulated by the possibility of gaining some advantages over conventional contact methods. Non-contact methods are becoming a milestone in performing non-destructive evaluation in several industrial fields, where hazardous environments, narrow spaces, high temperatures, and complex geometries are encountered. Such methods exploit photo-acoustic interactions between light and sound waves. This work compares two non-contact laser-based methods for detecting artificial flaws of different sizes in metallic specimens. It uses multi-signal homodyne interferometry and single beam deflectom…

Implementation of a fast and low cost IR-NDT technique by means of a Square Pulse modulated Lock-In Thermography

2012

This work describes the development of an IR-NDT procedure based on a lock-in signal treatment in the frequency domain to obtain phase-contrast defect signatures. Heat stimulation is obtained by periodically shattering a common low-power halogen lamp. The delivered heat is then modulated as a train of square waves with multi-frequency harmonic content. The proposed lock-in algorithm is able to selectively retrieve phase and amplitude information at various frequencies of the acquired temperature, acting also as a narrow band filter to improve defect-signature to noise ratio. The procedure is implemented and evaluated by means of low cost IR equipment to investigate artificially defected thi…

Robotic non-destructive inspection

2012

Automation of non-destructive testing (NDT) of engineering components and structures represents one of the strategic objectives of many industries. It enables increases in accuracy, precision and speed of inspection while reducing production time and associated labour costs in contrast to manual inspection. The use of robots can provide additional flexibility and autonomy to automated NDT. Automated robotic inspection can be beneficial in diverse industrial scenarios ranging from integration of NDT into the manufacturing process of components with very complex geometry, such as gears, to periodical in-service overhaul of large structures (for instance, in petrochemical and aerospace industr…