Lagrangian Coherent Structures: A Climatological Look

A relatively new area at the crossroads of fluid and nonlinear dynamics are objects known as Lagrangian Coherent Structures (LCSs). LCSs are mathematically classified to differentiate parts of fluid flows. They, themselves, are the most influential parts of fluids. These objects have the most influence on the fluids around them and they allow for a sense of hierarchy in an otherwise busy environment of endless variables and trajectories. While all particles of fluids have the same dynamics on an individual basis, areas of fluid are not created equal and to be able to detect which parts will be the most important to look at allows for easier, but just as accurate, prediction of fluid movement. Recent applications include cleanup operations during the BP Deepwater Horizon oil spill, pollutant transfer in oceanic basins, and the analysis of polar storm activity. This thesis explores LCSs from the discrete mathematics to the future climatological impacts using virtual fluid simulations and LCS detection tools to facilitate analysis as well as diving into a case study with real and unapproximated oceanic data in the days following the Fukushima Daiichi nuclear power plant disaster

Realistic simulation and animation of clouds using SkewT-LogP diagrams

Nuvens e clima são tópicos importantes em computação gráfica, nomeadamente na simulação e animação de fenómenos naturais. Tal deve-se ao facto de a simulação de fenómenos naturais−onde as nuvens estão incluídas−encontrar aplicações em filmes, jogos e simuladores de voo. Contudo, as técnicas existentes em computação gráfica apenas permitem representações de nuvens simplificadas, tornadas possíveis através de dinâmicas fictícias que imitam a realidade. O problema que este trabalho pretende abordar prende-se com a simulação de nuvens adequadas para utilização em ambientes virtuais, isto é, nuvens com dinâmica baseada em física que variam ao longo do tempo. Em meteorologia é comum usar técnicas de simulação de nuvens baseadas em leis da física, contudoossistemasatmosféricosdeprediçãonuméricasãocomputacionalmente pesados e normalmente possuem maior precisão numérica do que o necessário em computação gráfica. Neste campo, torna-se necessário direcionar e ajustar as características físicas ou contornar a realidade de modo a atingir os objetivos artísticos, sendo um fator fundamental que faz com que a computação gráfica se distinga das ciências físicas. Contudo, simulações puramente baseadas em física geram soluções de acordo com regras predefinidas e tornam-se notoriamente difíceis de controlar. De modo a enfrentar esses desafios desenvolvemos um novo método de simulação de nuvens baseado em física que possui a característica de ser computacionalmente leve e simula as propriedades dinâmicas relacionadas com a formação de nuvens. Este novo modelo evita resolver as equações físicas, ao apresentar uma solução explícita para essas equações através de diagramas termodinâmicos SkewT/LogP. O sistema incorpora dados reais de forma a simular os parâmetros necessários para a formação de nuvens. É especialmente adequado para a simulação de nuvens cumulus que se formam devido ao um processo convectivo. Esta abordagem permite não só reduzir os custos computacionais de métodos baseados em física, mas também fornece a possibilidade de controlar a forma e dinâmica de nuvens através do controlo dos níveis atmosféricos existentes no diagrama SkewT/LogP. Nestatese,abordámostambémumoutrodesafio,queestárelacionadocomasimulação de nuvens orográficas. Do nosso conhecimento, esta é a primeira tentativa de simular a formação deste tipo de nuvens. A novidade deste método reside no fato de este tipo de nuvens serem não convectivas, oque se traduz nocálculodeoutrosníveis atmosféricos. Além disso, atendendo a que este tipo de nuvens se forma sobre montanhas, é também apresentadoumalgoritmoparadeterminarainfluênciadamontanhasobreomovimento da nuvem. Em resumo, esta dissertação apresenta um conjunto de algoritmos para a modelação e simulação de nuvens cumulus e orográficas, recorrendo a diagramas termodinâmicos SkewT/LogP pela primeira vez no campo da computação gráfica.Clouds and weather are important topics in computer graphics, in particular in the simulation and animation of natural phenomena. This is so because simulation of natural phenomena−where clouds are included−find applications in movies, games and flight simulators. However, existing techniques in computer graphics only offer the simplified cloud representations, possibly with fake dynamics that mimic the reality. The problem that this work addresses is how to find realistic simulation of cloud formation and evolution, that are suitable for virtual environments, i.e., clouds with physically-based dynamics over time. It happens that techniques for cloud simulation are available within the area of meteorology, but numerical weather prediction systems based on physics laws are computationally expensive and provide more numerical accuracy than the required accuracy in computer graphics. In computer graphics, we often need to direct and adjust physical features, or even to bend the reality, to meet artistic goals, which is a key factor that makes computer graphics distinct from physical sciences. However, pure physically-based simulations evolve their solutions according to pre-set physics rules that are notoriously difficult to control. In order to face these challenges we have developed a new lightweight physically-based cloudsimulationschemethatsimulatesthedynamicpropertiesofcloudformation. This new model avoids solving the physically-based equations typically used to simulate the formation of clouds by explicitly solving these equations using SkewT/LogP thermodynamic diagrams. The system incorporates a weather model that uses real data to simulate parameters related to cloud formation. This is specially suitable to the simulation of cumulus clouds, which result from a convective process. This approach not only reduces the computational costs of previous physically-based methods, but also provides a technique to control the shape and dynamics of clouds by handling the cloud levels in SkewT/LogP diagrams. In this thesis, we have also tackled a new challenge, which is related to the simulation oforographic clouds. From ourknowledge, this isthefirstattempttosimulatethis type of cloud formation. The novelty in this method relates to the fact that these clouds are non-convective, so that different atmospheric levels have to be determined. Moreover, since orographic clouds form over mountains, we have also to determine the mountain influence in the cloud motion. In summary, this thesis presents a set of algorithms for the modelling and simulation of cumulus and orographic clouds, taking advantage of the SkewT/LogP diagrams for the first time in the field of computer graphics

Animating Unpredictable Effects

Uncanny computer-generated animations of splashing waves, billowing smoke clouds, and characters’ flowing hair have become a ubiquitous presence on screens of all types since the 1980s. This Open Access book charts the history of these digital moving images and the software tools that make them. Unpredictable Visual Effects uncovers an institutional and industrial history that saw media industries conducting more private R&D as Cold War federal funding began to wane in the late 1980s. In this context studios and media software companies took concepts used for studying and managing unpredictable systems like markets, weather, and fluids and turned them into tools for animation. Unpredictable Visual Effects theorizes how these animations are part of a paradigm of control evident across society, while at the same time exploring what they can teach us about the relationship between making and knowing

The Human race

To tell a story and to tell it well is a paramount function in human society. Whether the desired outcome is to engage, educate, or entertain the viewer the goal is the same. Through story we endeavor to learn something more about ourselves and hopefully show others something new within themselves. As the old adage goes, Give a man a fish you feed him for a day. Teach that man how to fish you feed him for a lifetime. One could simply give that hungry man a pole, a line, a hook, and a worm and give him directions on how to fish and he may or may not get the general idea. But if you tell him a story about how a starving man was able to feed himself and his entire family because another man taught him to fish, he will be engaged. He will want to be like this man and a good story would teach him all he needs to know. Stories are explorations into the state of the human condition. Through humorous stories we can more easily engage viewers with difficult subjects. They will let down their various filters and allow themselves to be confronted with a troubling topic, usually without their realization. One purpose of this story is to teach people something about the way we reproduce in a highly abstracted and entertaining way. An admittedly more selfish goal of mine was to learn how to better tell a story visually using the established film grammar through the use of computer generated imagery (CGI)

Computer-Assisted Interactive Documentary and Performance Arts in Illimitable Space

This major component of the research described in this thesis is 3D computer graphics, specifically the realistic physics-based softbody simulation and haptic responsive environments. Minor components include advanced human-computer interaction environments, non-linear documentary storytelling, and theatre performance. The journey of this research has been unusual because it requires a researcher with solid knowledge and background in multiple disciplines; who also has to be creative and sensitive in order to combine the possible areas into a new research direction. [...] It focuses on the advanced computer graphics and emerges from experimental cinematic works and theatrical artistic practices. Some development content and installations are completed to prove and evaluate the described concepts and to be convincing. [...] To summarize, the resulting work involves not only artistic creativity, but solving or combining technological hurdles in motion tracking, pattern recognition, force feedback control, etc., with the available documentary footage on film, video, or images, and text via a variety of devices [....] and programming, and installing all the needed interfaces such that it all works in real-time. Thus, the contribution to the knowledge advancement is in solving these interfacing problems and the real-time aspects of the interaction that have uses in film industry, fashion industry, new age interactive theatre, computer games, and web-based technologies and services for entertainment and education. It also includes building up on this experience to integrate Kinect- and haptic-based interaction, artistic scenery rendering, and other forms of control. This research work connects all the research disciplines, seemingly disjoint fields of research, such as computer graphics, documentary film, interactive media, and theatre performance together.Comment: PhD thesis copy; 272 pages, 83 figures, 6 algorithm

Self fish

Without the pursuit of love and happiness, breath is simply the sand of an hourglass pouring away to our time of passing. Love is the reason we are alive. To spend even a moment in misery is a moment wasted. Love is the goal of humanity. Everyone has or will experience love in its many forms over the course of a lifetime. Many, out of ignorance, habit, or sheer desperation, will fall in love with the wrong person. Most of us have or will have that one failed relationship, the one we reflect on as the relationship that taught us the most about who we are, what makes us happy, and what we seek or try to avoid in a mate. Through failure we learn what we can improve about ourselves. We learn that there are no perfect people and to try to make them that way is a losing battle, a never-ending, fruitless effort. Regardless, we will always try. Our happiness is dependent upon our honesty in defining ourselves. That is, if you are not happy, you cannot make yourself so simply by ignoring your own needs and catering to the needs of others. Additionally, you cannot make others happy by projecting your happiness upon them. When we are happy, we are being honest, even if only with ourselves. Unhappiness is wanting. If our needs are not being met, we seek to fulfill them, regardless of the consequences and often at the expense of our relationships and those we care about. In Self Fish, the hero has all that he needs, all except someone to share his life with. He is in search of a companion that he can love and who will love him in return. He is wary, as anyone would be, of welcoming someone into his world. Eventually He finds what he thinks will be a loyal, low-maintenance companion: the fish. We all know that in real life, fish are not a pet that one would typically consider affectionate. You can\u27t touch or pet a fish, and fish do not show loyalty or attachment. They can\u27t coexist in our environment without a substantial investment in special equipment. And, although fish owners insist on naming and assigning personality traits to their beloved aquatic friends, fish have but one facial expression, and are not capable of even simulating emotion. We are nothing to fish but a potential predators or potential prey. The fish character in my film is a metaphor for just this sort of emotional detachment. My fish character does emote; it shows significant discomfort, but does not reciprocate the love the hero has for the fish. It only admires its own reflection. Try as he might to please the fish, the hero cannot convince the fish to love him in return. His love turns to frustration, then to desperation, to resentment, and eventually to hatred. In the end he is helplessly trapped in an unreciprocated relationship where all amenities favor the fish. I have played the role of the main character depicted in my film many times in my life, but, more often than not, I have played the role of the fish. To those for whom I have been a fish, I sincerely apologize for my self-fishness. Please consider this story as an acknowledgement of guilt and an attempt to convey my regret for having treated you so cruelly. It seems one needs to be a fish before he can become a man. One needs to be a man before he can realize he has been a fish

Studio Ghibli’s landscapes and animation: design, characteristics and process

This dissertation joins the vibrant discussion in the animation and art industry about the impact of digital technology on culture and older more traditional hand drawn techniques, which are still used by art houses such as Studio Ghibli. It explores the visionary presence that digital techniques have had mainly in Japanese animation culture. From the perspective of someone who has been closely following the main animation houses for a long time, the mix of an autoethnographic and theory-based approach helped give clarity to the changing field and its impact on culture. Looking at key thinkers such as Blaire(2015) and Sullivans(2005) dissection of the research method, allowed me to combine my thoughts on digital evolution in animation while linking it to a theoretical framework. By analysing concrete narrative studies used by Theorists such as Bigelow(2009) and Wells(2002) and then combining that with industry artists of both traditional and modern techniques, I demonstrate that late 20th century aesthetics of art and design in Japanese anime can be pushed to new heights with use of digital technology but also explore the possible drawbacks to traditional styles it would have. Breaking down modern stereotypes of Japanese animation as viewed by western culture was a fundamental point in this research and was achieved by analysing the artistic differences using case studies between different art directors including Hayao Miyazaki and Makoto Shinkai.

Animating jellyfish through numerical simulation and symmetry exploitation

This thesis presents an automatic animation system for jellyfish that is based on a physical simulation of the organism and its surrounding fluid. Our goal is to explore the unusual style of locomotion, namely jet propulsion, which is utilized by jellyfish. The organism achieves this propulsion by contracting its body, expelling water, and propelling itself forward. The organism then expands again to refill itself with water for a subsequent stroke. We endeavor to model the thrust achieved by the jellyfish, and also the evolution of the organism's geometric configuration. We restrict our discussion of locomotion to fully grown adult jellyfish, and we restrict our study of locomotion to the resonant gait, which is the organism's most active mode of locomotion, and is characterized by a regular contraction rate that is near one of the creature's resonant frequencies. We also consider only species that are axially symmetric, and thus are able to reduce the dimensionality of our model. We can approximate the full 3D geometry of a jellyfish by simulating a 2D slice of the organism. This model reduction yields plausible results at a lower computational cost. From the 2D simulation, we extrapolate to a full 3D model. To prevent our extrapolated model from being artificially smooth, we give the final shape more variation by adding noise to the 3D geometry. This noise is inspired by empirical data of real jellyfish, and also by work with continuous noise functions from the graphics community. Our 2D simulations are done numerically with ideas from the field of computational fluid dynamics. Specifically, we simulate the elastic volume of the jellyfish with a spring-mass system, and we simulate the surrounding fluid using the semi-Lagrangian method. To couple the particle-based elastic representation with the grid-based fluid representation, we use the immersed boundary method. We find this combination of methods to be a very efficient means of simulating the 2D slice with a minimal compromise in physical accuracy

Interactive visualizations of unstructured oceanographic data

The newly founded company Oceanbox is creating a novel oceanographic forecasting system to provide oceanography as a service. These services use mathematical models that generate large hydrodynamic data sets as unstructured triangular grids with high-resolution model areas. Oceanbox makes the model results accessible in a web application. New visualizations are needed to accommodate land-masking and large data volumes. In this thesis, we propose using a k-d tree to spatially partition unstructured triangular grids to provide the look-up times needed for interactive visualizations. A k-d tree is implemented in F# called FsKDTree. This thesis also describes the implementation of dynamic tiling map layers to visualize current barbs, scalar fields, and particle streams. The current barb layer queries data from the data server with the help of the k-d tree and displays it in the browser. Scalar fields and particle streams are implemented using WebGL, which enables the rendering of triangular grids. Stream particle visualization effects are implemented as velocity advection computed on the GPU with textures. The new visualizations are used in Oceanbox's production systems, and spatial indexing has been integrated into Oceanbox's archive retrieval system. FsKDTree improves tree creation times by up to 4x over the C# equivalent and improves search times by up to 13x compared to the .NET C# implementation. Finally, the largest model areas can be viewed with current barbs, scalar fields, and particle stream visualizations at 60 FPS, even for the largest model areas provided by the service