Thomas Fidler

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Time seems to accelerate with increasing age. This subjective acceleration or compression may be due to the operation of a linear or a square-root function that relates present age to past age. A subjective magnitude-estimation technique was applied in a questionnaire given to 282 university students to determine which function best fitted the data. The(More)
A community volunteer programme was initiated in rural Jamaica in May 1990. The main aim of the programme was to monitor the growth of children less than 36 months of age through community health volunteers (CHVs) and improve their nutritional status. At the end of the second year the programme was evaluated to determine its effectiveness. The results of(More)
This article is concerned with a version of photoacoustic computed tomography, that uses line detectors (instead of point-like ones) for the recording of induced acoustical data. The three dimensional imaging problem, consisting in reconstructing the unknown density function from recorded data, is reduced to a series of two dimensional problems: First, the(More)
Abstract. Integral invariants have been proven to be useful for shape matching and recognition, but fundamental mathematical questions have not been addressed in the computer vision literature. In this article we are concerned with the identifiability and numerical algorithms for the reconstruction of a star-shaped object from its integral invariants. In(More)
Recently, integral invariants and according signatures have been identified to be useful for shape classification, which is an important research topic in computer vision, artificial intelligence and pattern recognition. The modelling of integral invariants and signatures for shape analysis and in particular the analysis have not attracted attention in the(More)
282 undergraduate students between 17 and 68 years of age were asked to list the 5 most significant experiences of their lives, to assign the time zones to these experiences, and to provide estimates of emotional valence corresponding to each significant life experience they listed. Subjects also provided judgements of time perspective on a Life Line. The(More)
This article is concerned with the representation of curves by means of integral invariants. In contrast to the classical differential invariants they have the advantage of being less sensitive with respect to noise. The integral invariant most common in use is the circular integral invariant. A major drawback of this curve descriptor, however, is the(More)
We investigate the applicability of integral invariants as geometrical shape descriptors in the context of ill-posed inverse problems. We propose the use of a Tikhonov functional, where the penalty term is based on the difference of integral invariants. As a case example, we consider the problem of inverting the Radon transform of an object with only(More)
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