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Typescript. Includes vita and abstract. Includes bibliographical references (leaves 61-65). Also available online.

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: interferometry, bridge inspection. Includes bibliographical references (p.97-100).

Calibration is a fundamental step towards producing radio interferometric images. However, naive calibration produces calibration artefacts, in the guise of spurious emission, buried in the thermal noise. This work investigates these calibration artefacts, henceforth referred to as “ghosts”. A 21 cm observation with the Westerbork Synthesis Radio Telescope yielded similar ghost sources, and it was anticipated that they were due to calibrating with incomplete sky models. An analytical ghost distribution of a two-source scenario is derived to substantiate this theory and to seek answers to the related bewildering features (regular ghost pattern, points spread function-like sidelobes, independent of model flux). The theoretically predicted ghost distribution qualitatively matches with the observational ones and shows high dependence on the array geometry. The theory draws the conclusion that both the ghost phenomenon and suppression of the unmodelled flux have the same root cause. In addition, the suppression of the unmodelled flux is studied as functions of unmodelled flux, differential gain solution interval and the number of sources subjected to direction-dependent gains. These studies summarise that the suppression rate is constant irrespective of the degree of incompleteness of the calibration sky model. In the presence of a direction-dependent effect, the suppression drastically increases; however, this increase can be compensated for by using longer solution intervals.

The commercial exploitation of Electronic Speckle Pattern Interferometry (ESPI) is now gathering pace with manufacturers marketing products in Europe and the USA. The power of the technique both in a research and an industrial inspection role has brought pressure from the engineering community for an automated fringe analysis system.

No description available.

With the majority of bridges in the country aging, over capacity and costly to rehabilitate or replace, it is essential that engineers refine their inspection and evaluation techniques. Over the past 130 years the information gathering techniques and methods used by engineers to inspect bridges have changed little. All of the available methods rely on one technique, visual inspection. In addition, over the past 40 years individual bridge inspectors have gone from being information gathers to being solely responsible for the condition rating of bridges they inspect. The reliance on the visual abilities of a single individual to determine the health of a particular bridge has led to inconsistent and sometimes erroneous results. In an effort to provide bridge inspectors and engineers with more reliable inspection and evaluation techniques, this thesis will detail the case for development of a new inspection tool, and the assembly and use of one new tool called Fringe Interferometry

Thesis--Karolinska Institutet. / Extra t.p. with thesis statement inserted. Four articles by the author reprinted from Acta odont. Scand. and Sc. ed. bull. in pocket. Includes bibliographical references (p. 31-34).

Thesis--Karolinska Institutet. / Extra t.p. with thesis statement inserted. Four articles by the author reprinted from Acta odont. Scand. and Sc. ed. bull. in pocket. Includes bibliographical references (p. 31-34).