Updating land-use information on topographic maps using satellite imagery : combining the advantages of two accessible sources of geographic information

This paper examines the possibilities of using Landsat Thematic Mapper images for updating land-use information on topographic maps. Information obtained from satellite images can be kept up-todate and a large number of classes can be distinguished. However, the quality of the information still leaves much to be desired, with a reliability of no...

Reliability of nondestructive inspection

This report describes the concept of reliability of nondestructive inspection (NDI) and reviews the different aspects involved. First, the probability of detection (POD) of flaws in flawed specimens is discussed. To provide a measure of confidence in an estimated POD, lower botind values of this probability at a given confidence level are...

Verification and validation of IRAS on-board software

The infrared Astronomical Satellite IRAS is equipped with an on-board computer system that takes care of vital satellite functions as attitude control, ground dialogue and execution of the observation programs. Therefore an important purpose of the IRAS system tests was the Verification and Validation of the on-board software. The test...

Reliability aspects of software for digital avionics

Modern commercial transport aircraft contain digital avionics systems for more and more safety critical functions. The reliability and safety of those new systems depend on the hardware reliability and on the reliability of the embedded software. In this report, an overview is given of available methods and techniques to develop reliable...

Evaluation of non-destructive inspection methods applied to milled step-down areas

The present report describes how fatigue cracks were produced in 102 specimens. After cracking these specimens were inspected non-destructively by means of eddy currents, ultrasonics. X-rays and penetrants, and the indications were recorded. Successively the specimens were exposed to corrosion whereafter the inspections were repeated. Upon...

IRAS on-board software

The infra Red Astronomical Satellite IRAS will be laimched in February I98I for a mission of one year duration. The purpose of the mission is to produce a full sky catalogue in the infrared waveband. The IRAS satellite will be equipped with an on-board computer system to control the satellite and to execute the measurements necessary to fulfil...

Study of double gimballed momentum wheels in the attitude and orbit control system of a geostationary communication satellite

The potentials of a double glmballed mcwientum wheel as an actuator for the attitude oontrol of a geostationary communication satellite are discussed with respect to the related systems. A justification of the IXaW is given and the characteristics defining the wheel system are determined. They can serve to be the input to a detailed design of an...