Vor den Dingen sind alle Besucher gleich. Kulturelle Bildungsprozesse in der musealen Ordnung

Museen bieten Chancen kultureller Bildung. In den durch Ordnungsvorstellungen normativ geprägten Inszenierungsräumen werden Dinge zu Trägern von Repräsentationen, die über gegenwärtigen Alltag hinausweisen. Dem wird eine Bildungsauffassung gerecht, die Museen nicht auf den Wissensvorrat ihrer Dingwelt eng führt, von bloßen pragmatischen Verwertungsinteressen der Gegenwart Abstand zu halten weiß und dingübergreifende Sinnkontexte erzeugen kann. Zugleich können die lebensgeschichtlichen Bildungsvoraussetzungen der Besucher nicht übergangen werden, gleichwohl diese vor den Dingen alle gleich sind. (DIPF/Orig.)Museums provide possibilities for cultural education. Within the halls of exhibition shaped by normative concepts of order, objects become vehicles for representations which point beyond present everyday life. This is done justice by a concept of education which does not limit the museum to the reservoir of knowledge carried by its world of objects, - a concept, which knows how to keep its distance from mere pragmatic present-day interests of utilization and which is able to generate contexts of meaning not restricted to the isolated object. Furthermore, the visitors\u27 educational background is not to be neglected, despite the fact that, in front of the objects, all visitors are equal. (DIPF/Orig.

Video-based calibration of holographic optical traps

Projecte final de carrera fet en col.laboració amb Universitat de Barcelona. Departament de Física Aplicada i ÒpticaHolographic optical tweezers give the possibility to dynamically generate multiple optical traps in arbitrary numbers and forms. This work investigates the implementation of the step response calibration method for a holographic optical tweezers system. The step response calibration is a promising method which requires the repeated subsequent generation and change of several trap positions for the calibration. It has not been undertaken yet using a holographic setup, despite the fact that using digital holography this necessary dynamic change is easier to achieve than with other setups used so far. We have implemented this method for multiple holographic traps calibration, and investigated new problems which arise due to the nature of the spatial light modulator included in the holographic setup. Some improvements to solve the drawbacks identified have been proposed and successfully implemented. Good results have been obtained for low trap stiffnesses between 0.5 to 3 pN/?m. The calibration of stronger traps was limited by the spatial light modulator response time.Pinzas ópticas holográficas dan la posibilidad de generar de forma dinámica múltiples trampas ópticas en un número arbitrario y formas. Este trabajo investiga la la aplicación del método de paso de calibración de respuesta para un óptico holográfico pinzas del sistema. La calibración de respuesta es un método prometedor que requiere la generación siguiente y repetir el cambio de las posiciones de varias trampas para el calibración. No se ha realizado aún utilizando una configuración holográfica, a pesar de que el uso de la holografía digital, esta dinámica de cambio necesario es fácil de lograr que con otras configuraciones utilizadas hasta ahora. Hemos implementado este método de múltiples trampas de calibración holográfica, y se investigan nuevos problemas que surgen debido a la naturaleza del modulador espacial de luz incluidos en la configuración holográfica. algunos mejoras para solucionar los inconvenientes identificados se han propuesto y con éxito implementado. Los buenos resultados se han obtenido para rigideces trampa de baja entre 0,5 a 3 pN /µm. La calibración de las trampas más fuerte se vio limitada por el modulador espacial de luz tiempo de respuesta.Pinces òptiques hologràfiques donen la possibilitat de generar de forma dinàmica múltiples trampes òptiques en un nombre arbitrari i formes. Aquest treball investiga la l'aplicació del mètode de pas de calibratge de resposta per un òptic hologràfic pinces del sistema. El calibratge de resposta és un mètode prometedor que requereix la generació següent i repetir el canvi de les posicions de diverses trampes per al calibratge. No s'ha realitzat encara utilitzant una configuració hologràfica, tot i que l'ús de l'holografia digital, aquesta dinàmica de canvi necessari és fàcil d'aconseguir que amb altres configuracions utilitzades fins ara. Hem implementat aquest mètode de múltiples trampes de calibratge hologràfica, i s'investiguen nous problemes que sorgeixen a causa de la naturalesa del modulador espacial de llum inclosos en la configuració hologràfica. alguns millores per solucionar els inconvenients identificats s'han proposat i amb èxit implementat. Els bons resultats s'han obtingut per rigideses trampa de baixa entre 0,5-3 pN/µm. El calibratge de les trampes més forta es va veure limitada pel modulador espacial de llum temps de resposta

Localization for mobile robots using panoramic vision, local features and particle filter

In this paper we present a vision-based approach to self-localization that uses a novel scheme to integrate feature-based matching of panoramic images with Monte Carlo localization. A specially modified version of Lowe’s SIFT algorithm is used to match features extracted from local interest points in the image, rather than using global features calculated from the whole image. Experiments conducted in a large, populated indoor environment (up to 5 persons visible) over a period of several months demonstrate the robustness of the approach, including kidnapping and occlusion of up to 90% of the robot’s field of view

Active people recognition using thermal and grey images on a mobile security robot

In this paper we present a vision-based approach to detect, track and identify people on a mobile robot in real time. While most vision systems for tracking people on mobile robots use skin color information, we present an approach using thermal images and a fast contour model together with a particle filter. With this method a person can be detected independently from current light conditions and in situations where no skin color is visible (the person is not close or does not face the robot). Tracking in thermal images is used as an attention system to get an estimate of the position of a person. Based on this estimate we use a pan-tilt camera to zoom to the expected face region and apply a fast face tracker in combination with face recognition to identify the person

Sample pre-treatment effects on identification of smectite by X-ray diffraction

Analysing the mineral assemblage of soils and their clay fractions requires extensive pre-treatment, such as removal of carbonates, iron oxides, and organic matter, as well as dispersion procedures. These pre-treatments affect the properties of target minerals, and thus, hamper their identification. Smectites, being expandable and of small particle size, are most prone to undesired changes upon pre-treatments. We studied the changes in X-ray diffraction patterns of smectite-dominated soil material (topsoil and subsoil of vertisols) in response to sequential pre-treatments. The sequence started with the removal of carbonates (by HCl), followed by the removal of iron oxides (dithionite-citrate-bicarbonate (DCB) method, without heating) and organic matter by H2O2 or NaOCl (at pH 8). Last, the samples were dispersed either in sodium pyrophosphate or sodium pyrophosphate in combination with sonication. Untreated material and material from each treatment step was magnesium-saturated, and then freeze dried. Textured specimen were analysed by X-ray diffraction. The pre-treatments had small effects of the position of the 001 reflection, with a tendency to larger d spacing with increasing numbers of pre-treatments. This suggests increasing accessibility of the interlayer spaces, probably by increasing dispersion of the samples. Also, the width of the 001 reflection was little affected by the different treatments. Pre-treatment of soil samples with HCl for removal of carbonates, with DCB for iron oxide removal, and with H2O2 for organic matter removal had either some positive or only little negative effects on the intensity of 001 reflection of smectite. Dispersion with pyrophosphate, especially in combination with sonication, strongly decreased the 001 reflection. Treatment with NaOCl resulted in a more complete removal of organic matter than H2O2, however, at the cost of a pronounced drop the intensity of the 001 reflection. In summary, all pre-treatments of soil samples for X-ray analyses have the potential to hamper the identification of smectite. The effect of the removal carbonate, iron oxides, and organic matter is little; these treatments may even support the identification in some samples. Dispersion with pyrophosphate or by sonication and the treatment with NaOCl may impair the identification of smectite in textured specimen

The aspirations and life goals of youth offenders at Lindelani Place of Safety

Thesis (MPhil (Sociology and Social Anthropology))--Stellenbosch University, 2008.Rising crime rates among the youth in South Africa is a major problem. In the Western Cape this concern is particularly urgent and is compounded by issues relating to gangsterism and drugs. This study analyses why youth offenders, based at Lindelani become involved in crime and how they subsequently see their future. The first part of the study reviews theories of crime and deviance, such as the classical school of criminology, psychological, biological and sociological explanations of crime. The usefulness of the criminological developmentalist approach toward identifying risk factors statistically correlated to the perpetration of crime is discussed. Common factors associated with crime in the South African context are identified including family, peers, gang, drug, school, media and neighbourhood related factors as well as the absence of spirituality. Thereafter the literature associated with the development of aspirations, life goals and the concept of possible selves is explained. The relationship between possible selves, aspirations and life goals are discussed and details regarding how possible selves influence delinquency are presented. Following the theoretical analysis, the problem of crime in South Africa with reference to the youths interviewed is outlined. The strategies pursued by government to combat crime are discussed and the effective potential of these approaches are evaluated. An overview of government’s policy toward youth in South Africa is given followed by specific reference to the issues surrounding youth and crime in the Western Cape, with explicit reference to the Cape Flats and gangs. This provides the background to the Lindelani case study. An overview of the operations and challenges facing Lindelani Place of Safety and the profile of offences typically committed by youth are given. Hereafter the findings are presented. The findings are divided into two sections; the first explores the life world of youth at Lindelani by discussing why youth in the Western Cape perpetrate crime and identifies factors that are associated with their involvement. The findings report on the influence of family and household structure, peers, neighbourhood environment, gangs, drugs, school, media, perceived aptitude of youth offenders, role models and spirituality. Section two presents the findings regarding the possible selves, life goals and aspirations of the youth. The general aspirations, possible selves, family aspirations, friendship, neighbourhood, spiritual, educational and occupational aspirations are explored. The study thereby presents the voices of these young offenders