Visual interpretation of Lambertian surface deformation

The major topic of this thesis is the interpretation (as a three-dimensional velocity field) of the changing intensity pattern induced by a smoothly deform¬ ing Lambertian surface of uniform albedo illuminated by a distant point light source. A constraint is derived which shows how the changing intensity pattern induced by such a deforming surface is locally constrained by the three-dimen¬ sional motion of that surface. This constraint, the "Intensity Rate Constraint", a partial differential equation in the normal component of surface velocity, con¬ tains no terms relating to the tangential components of surface velocity, hence the problem of determining the three-dimensional motion is ill-posed. The ap¬ plication of an additional constraint on the motion, (implemented in the form of a stretch-based regulariser) is proposed. This enables certain psychologi¬ cally significant classes of three-dimensional velocity field over the surface to be estimated veridically from the image intensity rate, the velocity field along the boundary and static information. This technique is successfully tested on synthetic data in experiments requiring at least ten times greater accuracy in intensity measurement than is commonly available. The thesis concludes with a suggested technique for the interpretation of smoothly deforming space-curve motion

Interactive advertising displays

Interactive public displays are the latest development in the field of out-of-home advertising. Throughout history characteristic shapes for billboards evolved such as flat rectangular displays, long displays or cylindrical advertising columns. This work presents novel interactive display designs that are based on these historical role models and allow passers-by to interact with them in a natural, touchless manner. It further pursues a vision where interactive public displays become more active themselves and actively influence passer-by behavior in order to increase their effectiveness, better attract attention and improve public interaction in front of them. First, to overcome the challenge that passers-by often do not expect public displays to be interactive and thus pay no attention to them, this work presents a solution called unaware initial interaction that surprises passers-by and communicates interactivity by giving visual feedback to their initial movements. To be effective, the visual feedback has to be designed considering the specific display shapes, their requirements to contents and the typical approaching trajectories. Second, to overcome the challenge that larger groups of passers-by often crowd together in front of wide public displays or do not take optimal positions for interaction, this work presents a solution to subtly and actively guide users by dynamic and interactive visual cues on the screen in order to better distribute them. To explore these concepts and following an initial analysis of the out-of-home domain and of typical display qualities, interactive counterparts to the classical display shapes are designed such as interactive advertising columns, long banner displays and life-size screens. Then interactive contents and visual feedbacks are designed which implement the presented interactivity concepts, and audience behavior around them is analyzed in several long-term field studies in public space. Finally the observed passer-by and user behavior and the effectiveness of the display and content designs are discussed and takeaways given that are useful for practitioners and researchers in the field of public interaction with out-of-home displays.Interaktive öffentliche Displays sind die neueste Entwicklung im Bereich der Außenwerbung. Im Laufe der Geschichte bildeten sich charakteristische Formen für Werbetafeln heraus wie flache rechteckige Displays, lange Displays oder zylindrische Werbesäulen. Die vorliegende Arbeit stellt neuartige Designs für Displays vor, die auf diesen historischen Vorbildern aufbauen und den Passanten erlauben, mit ihnen auf eine natürliche, berührungslose Art und Weise zu interagieren. Darüber hinaus verfolgt sie eine Vision, in der interaktive öffentliche Displays aktiver werden und entsprechend das Passantenverhalten beeinflussen, um ihre Wirksamkeit zu erhöhen, mehr Aufmerksamkeit auf sich zu ziehen und die öffentliche Interaktion mit ihnen zu verbessern. Zunächst stellt diese Arbeit eine als Unbewusste Initialinteraktion bezeichnete Lösung vor, welche die Passanten überrascht und mittels visuellem Feedback auf ihre anfänglichen Bewegungen Interaktivität übermittelt, um die Herausforderung zu bewältigen, dass Passanten oft nicht erwarten, dass öffentliche Displays interaktiv sind und sie ihnen somit keine Aufmerksamkeit schenken. Um effektiv zu sein, muss das visuelle Feedback dabei so gestaltet werden, dass es die spezifischen Displayformen, ihre Anforderungen an die dargestellten Inhalte und ihre typischen Annäherungswege berücksichtigt. Zweitens stellt sie eine Lösung vor, bei der die Nutzer auf subtile Weise und durch auf dem Bildschirm dargestellte dynamische und interaktive visuelle Reize aktiv geführt werden, um sie besser vor dem Display zu verteilen, um die Herausforderung zu bewältigen, dass größere Gruppen von Passanten sich oft vor breiten öffentlichen Displays zusammendrängen oder keine optimalen Positionen für die Interaktion einnehmen. Zur Erforschung dieser Konzepte werden im Anschluss an eine einführende Analyse von Außenwerbedisplays und ihrer typischen Eigenschaften interaktive Entsprechungen der klassischen Displayformen entwickelt wie interaktive Litfaßsäulen, lange Bannerdisplays und Life-size Screens. Weiter werden für diese Displays interaktive Inhalte und visuelle Feedbacks entwickelt, welche die vorgestellten Interaktivitätskonzepte umsetzen und das Verhalten des anwesenden Publikums in mehreren Langzeit-Feldstudien im öffentlichen Raum untersucht. Schließlich werden das beobachtete Passanten- und Nutzerverhalten und die Effektivität der entwickelten Display-Designs und Inhalte bewertet und nützliche Empfehlungen für Praktiker und Forscher auf dem Gebiet der öffentlichen Interaktion mit Außenwerbedisplays gegeben

Advanced Knowledge Application in Practice

The integration and interdependency of the world economy leads towards the creation of a global market that offers more opportunities, but is also more complex and competitive than ever before. Therefore widespread research activity is necessary if one is to remain successful on the market. This book is the result of research and development activities from a number of researchers worldwide, covering concrete fields of research

Geometries of Light and Shadows, from Piero della Francesca to James Turrell

This chapter addresses the problem of representing light and shadow in the artistic culture, from its uncertain beginnings, related to the studies on conical linear perspective in the Fifteenth Century, to the applications of light projection in the installations of contemporary art. Here are examined in particular two works by two artists, representing two different conceptual approaches to the perception and symbolism of light and shadow. The first is the so-called Brera Madonna by Piero della Francesca, where the image projected from a luminous radiation is employed with a narrative purpose, supporting the apparently hidden script of the painting and according to the artist\u2019s own speculations about perspective as a means to clarify the phenomenal world. The second is one of James Turrell\u2019s Dark Spaces installations, where quantum electrodynamics interpretation of light is taken into account: for Turrell, light is physical and thus can shape spaces where the visitors, or viewers, can \u201csee themselves seeing.\u201d In his body of work, perceptual deceptions are carefullyproduced by the interaction of the senses with his phenomenal staging of light and darkness, but a strong symbolic component is always present, often related to his own speculative interests. In both cases, light and shadow, through their geometries, emphasize both phenomenal and spiritual contents of the work of art, intended as a device to expand the perception and the knowledge of the viewer

Dynamics of a class of vortex rings

The contour dynamics method is extended to vortex rings with vorticity varying linearly from the symmetry axis. An elliptic core model is also developed to explain some of the basic physics. Passage and collisions of two identical rings are studied focusing on core deformation, sound generation and stirring of fluid elements. With respect to core deformation, not only the strain rate but how rapidly it varies is important and accounts for greater susceptibility to vortex tearing than in two dimensions. For slow strain, as a passage interaction is completed and the strain relaxes, the cores return to their original shape while permanent deformations remain for rapidly varying strain. For collisions, if the strain changes slowly the core shapes migrate through a known family of two-dimensional steady vortex pairs up to the limiting member of the family. Thereafter energy conservation does not allow the cores to maintain a constant shape. For rapidly varying strain, core deformation is severe and a head-tail structure in good agreement with experiments is formed. With respect to sound generation, good agreement with the measured acoustic signal for colliding rings is obtained and a feature previously thought to be due to viscous effects is shown to be an effect of inviscid core deformation alone. For passage interactions, a component of high frequency is present. Evidence for the importance of this noise source in jet noise spectra is provided. Finally, processes of fluid engulfment and rejection for an unsteady vortex ring are studied using the stable and unstable manifolds. The unstable manifold shows excellent agreement with flow visualization experiments for leapfrogging rings suggesting that it may be a good tool for numerical flow visualization in other time periodic flows

Design For Movement: Block Pattern Design For Stretch Performancewear

This thesis is in 2 volumesPattern drafting techniques for woven block patterns have been well established. Applying existing techniques with modifications to generate patterns for modern stretch fabrics can be successful but it is often at a cost. In the development of a stretch pattern, an acceptable fit cannot be guaranteed merely by using a rationalised simple pattern profile shape. Producing a pattern, without darts, to closely adhere to the contours of the body without restricting movement, is a contradiction in design terms. In woven fabric, darts and ease are used to manipulate the fabric around the form and allow movement. However, in stretch knit fabric the development of a block pattern involves the synthesis of information from a variety of disciplines and requires a more specialist approach. This study has endeavoured to show that a new interpretation of pattern design principles is needed to create an improved stretch block pattern for stretch knit performancewear. This work has been refined based on a new method of classifying stretch fabric parameters and personal observation of the effect of stretch distortion characteristics and the changes that occur in the twodimensional pattern profile, when stretched to conform to the threedimensional body. The results of this study will provide a more SCientific and practical approach to assessing stretch fabric parameters as an integral part of block pattern design for stretch performancewear. The fabric stretch potential has been maximised to contour the body for optimum fit, providing comfort and mobility without the need for redistribution of the fabric when activity ceases. A method of creating a stretch block pattern from direct measurements to replicate the body shape and proportions was devised which can be reduplicated. This study addresses primarily the designer/pattern cutter who has a passion for good fit, which enhances comfort and mobility, who does not necessarily have a scientific background. However this study is relevant to the textile technologist concerned with proposing a standard to compare stretch fabrics for garment production. It should also appeal to the computer programmer concerned with the link between 3D body scanning and interpreting the body profile accurately in the 2D pattern draft

SURFO Technical Report No. 19-02

The 2019 technical reports written by undergraduate students participating in the SURFO (Summer Undergraduate Research Fellowships in Oceanography) Program while at the University of Rhode Island

Pressure Gain Combustion: Fuel Spray and Shockwave Interaction

Pressure gain combustion can attain higher thermodynamic cycle efficiency in gas turbine power systems, resulting in the reduction of specific fuel consumption/fuel burn and Carbon dioxide emissions.There are many ways to achieve pressure gain and the present research investigates pressure gain through shock bubble (gas and liquid bubble) interaction (SBI) using computational fluid dynamics (CFD) simulations. The numerical simulations have been performed in 2D and 3D representations of the shock tube to depict the interaction of a planar shock wave with distinct gas and liquid inhomogeneities. The three scenarios considered cover the interaction of a planar shock wave in air with: spherical helium bubble (Mach number, Ma = 1.25); cylindrical helium bubble (Ma = 1.22) and cylindrical water bubble (Ma = 1.47). To perform these simulations, the Unsteady Reynolds-Averaged Navier-Stokes (URANS) mathematical model and the coupled level set and VOF method within the commercial CFD code, ANSYS FLUENT, have been applied. A finite volume method (FVM) is also employed to solve the governing equations. For the spherical and cylindrical gas bubble cases, various quantitative analyses are presented and compared to the experimental work of Haas and Sturtevant (1987). These include: refracted wave, transmitted wave, upstream interface, downstream interface, jet, vortex filament, non-dimensional bubble, and vortex velocities. The predicted non-dimensional bubble and vortex velocities have also been compared with experimental data, a simple model of shock- induced Rayleigh Taylor (RT) instability and other theoretical models. Comparisons are also shown between the predicted bubble length/width and the experimentally measured results to elucidate changes in the shape and size of the 2D and 3D bubbles. Additional quantitative analyses are also presented for the spherical bubble involving the size estimation of the vortex pair as well as their spacing. For the shock cylindrical water bubble interaction case, the quantitative predictions include: displacement/drift, acceleration, distortion in the lateral direction, distortion in flow direction, area variation from bubble distortion, as well as drag coefficient and are compared to the experimental measurements of Igra et al. (2002). It has been demonstrated that 3D simulations compare very well with the experimental data, suggesting that 3D simulations are necessary to capture SBI process accurately. Finally, comprehensive flow visualization has been used to elucidate the shock-bubble interaction (SBI) process from bubble compression to the formation of the vortex filaments (cylindrical helium bubble), vortex rings (spherical helium bubble), vortices (cylindrical water bubble) as well as the production and distribution of vorticity. It is demonstrated for the first time that turbulence is generated at the early phase of the SBI process, with the maximum turbulence intensity reaching about 20% around the vortex filaments/vortex rings regions for the cylindrical/spherical helium bubble cases respectively and about 22% for the cylindrical water bubble case at the later phase of the interaction process