Thesis (Ph. D.)--Open University. BLDSC no. DX227302.

Diss.--Basel. / Bibliography: p. 224-228.

The problem of this study was to investigate the effect of the rotation around two axes of the body upon static balance as measured by the stork stand, the headstand, and the one foot balance.

In this dissertation, a new approach for determining gaze direction is presented. This approach is based on the existence of a visual axes center for the human eye, the location of which is invariant with respect to the head. The vector from the visual axes center of an eye through the pupil center provides a reliable approximation for a gaze vector. Calibration camera images of human subjects looking at known points on a computer monitor are collected in a non-intrusive manner. Algorithms are applied to the images from two independent cameras whose spatial relationship is known with respect to the monitor. The calibration algorithms allow determination of physical distances between selected facial features visible in the images and the invariant location of the visual axes center for each eye (not visible) with respect to these features. Given these invariant relationships between a subject's facial features and eye visual axes centers, optimization techniques are applied to subsequent images collected from a single camera to obtain the three-dimensional locations of the visible facial features and the visual axes centers, and from these, the gaze direction. The results of experiments conducted to determine the viability and accuracy of the visual axes center approach in determining the gaze direction are presented. The results show that the approach can provide acceptable gaze direction error values when high accuracy (< 1° angular error) is not required. Techniques to improve accuracy are discussed as well as potential limitations of the approach.

This thesis presents a systematic scheme to determine the optimal propulsive/axial force ratio of a single-sided permanent magnet axial-flux motor (SPMAM) along with its operational constraints on both the winding currents and the speed induced voltages. According to the rotating magnetic field theory with combining the recoil line characteristics of permanent magnet and the equivalent operational magnetic circuits, appropriate projection of the stator currents to achieve an optimal ratio of the machine propulsive/axial forces has been confirmed through detailed three-dimensional finite element analysis (3-D FEA) and numerical studies. From these evaluations, a feasible operational guidance for SPMAM field oriented control (FOC) scheme realizations can be suitably provided. Finally, based on the proposed optimal scheme, a DSP-based drive system has been successfully implemented, and the desired operational strategy realization can be achieved.

Presently, there are a lot of applications of gear sets with skew axes, some of them, especially worm gear sets and hypoid gear sets, are widely used. Take hypoid gear as example, gear sets produced by different gear factories can¡¦t fit to each other. Due to the lacking in common properties among different systems, it is disadvantageous to integrated application of development of gear researches. Therefore, a common mathematical constructive model is necessary to be established. The main content of this thesis is to construct the mathematical parametric model and the partial differential constraint equation according to the rigid-body transformation theory and General Theorem of Conjugate Surfaces. After finding out the solution from the partial differential constraint equation, a new line-contacted type of tooth profile of gear sets with skew axes, quality analyses to the parameters of gear profile rendered are proceeded. Finally, utilize the software of motion simulation to simulate the operating situation of the linear contacted type of gear sets with skew axes constructed, and supply the demonstration of the theory of tooth profile of gear sets and properties of gear sets.

The aim of this essay is to investigate the impact bronze had on the South Scandinavian society during the period 2400-1700 B.C. What happened when bronze began to arrive in the Scandinavian Late Neolithic society? How did it spread and how did this influence the society.

Dissertation--Stockholms universitet, 2007.

Neste trabalho, estuda-se propriedades e implementações de duas importantes representações de formas denominadas curvatura e eixos de simetria (ou esqueletos), relacionando-as ao clássico modelo de processamento da informação visual proposto por Marr. Para tanto, fez-se necessária uma releitura dos critérios para a representação de formas já existentes, além da proposição e comparação de algumas abordagens numéricas através das quais curvaturas e esqueletos são calculados, com especial atenção dada a características como robustez e invariância. No caso da curvatura, que é uma medida clássica da geometria diferencial sem divergências quanto a sua definição e interpretação, foi dado maior enfoque à robustez dos métodos quanto à presença de ruídos de diversas naturezas e quanto a sensibilidade na escolha dos parâmetros que levaram aos resultados mais precisos. Além disso, propôs-se uma versão não-derivativa da curvatura (denominada circularidade local) a fim de contornar o problema advindo das instabilidades do cálculo de derivadas de dados reais amostrados. Ainda relativamente à curvatura, um método baseado na transformada de Fourier bidimensional foi proposto e comparado à abordagem unidimensional já estabelecida e a outro método padrão (&#946-Splines/ Medioni) de cálculo de curvatura de contornos digitais. Já no caso dos esqueletos, a existência de diversas interpretações geométricas e matemáticas para o conceito e as inúmeras abordagens numéricas para o cálculo dos mesmos demandaram a revisão da literatura sob a luz do modelo inicialmente introduzido para que se pudesse impor uniformidade à terminologia e situar as diferentes abordagens e implementações dentro de um panorama comum, sendo que dois novos métodos para o cálculo de esqueletos foram criados quando do desenvolvimento deste trabalho (esqueletos por dilatações exatas e esqueletos afins baseados em áreas). / In this work, properties and implementations of two important shape representa¬tions had been studied: curvature and symmetry axis (or skeletons) and they had been related to the Marr\'s classical visual information processing model. Thus, it was necessary a re-interpretation of previously existent criteria for shape represen¬tation in addition to the proposition and comparison of some numerical approaches for curvature and skeletons calculations with special attention given to robustness and invariance characteristics. In the curvature case, a classic measure from dif¬ferential geometry with no divergence about its definition and interpretation, we focused mainly on the numerical methods robustness in presence of several noise categories and on the best parameter set choice sensibility. Additionally, a no derivative version of curvature (also called local circularity) was proposed in order to circumvent problems related to the sampled real data derivatives numerical ins¬tabilities. Still talking about curvature, a 2D Fourier transform based method had been proposed and assessed in comparison to the 1D approach and other standard digital contour curvature calculation method (&#946-Splines/ Medioni). In the skeleton\'s case, the existence of several geometrical and mathematical interpretations of the concept and the innumerable numeric approaches to their calculation demanded a literature survey regarding the initially introduced model to impose uniformity to the terminology and to situate the different approaches and implementations into a common framework where two new methods to skeleton\'s calculations had been created (exact dilations based skeletons and area based affine skeletons).

My intention with this paper is to try to understand the meaning of the double sex symbols which can be identified on a number of Neolithic so called battle axes from the region round the lake Mälaren in Sweden. My conclusions are drawn after having studied a number of archaeological thesises. I have realized that the society was egalitarian from what is said about the funeral habits since women and men were buried with the same care. Ceramics from the Skogsmossen site show a very long continuity over 15-20 generations. These facts indicate a peaceful society without traumatic breaks where knowledge would have been lost. The fingerprints produced on the ceramics are those of women, since they do not seem to fit with the hands of men. Women are by this fact persumed to be the producers of ceramics. In early and primitive farming digging sticks were used, often with a weight. My conclusion is that the boat axe can be a magic tool used on the digging sticks. We have to understand the boat axes as spiritual helpers to fruitful and fertile success.