1,607 research outputs found
Interactive Terrain Simulation and Force Distribution Models in Sand Piles
This paper presents an application of Cellular Automata in the field of dry Granular Systems modelling. While the study of granular systems is not a recent field, no efficient models exist, from a computational point of view, in classical methodologies. Some previous works showed that the use of Cellular Automata is suitable for the development of models that can be used in real time applications. This paper extends the existing Cellular Automata models in order to make them interactive. A model for the reaction to external forces and a pressure distribution model are presented and analyzed, with numerical examples and simulations
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Drift-diffusion based real-time dynamic terrain deformation
In the natural world, terrains are dynamic entities that change their morphology due to their interaction with other agents in the environment. However, in real-time applications terrains are often represented as static meshes, which present no interaction capabilities. This paper presents a novel real-time 2D method for dynamic terrain simulations, aimed for applications in the entertainment industry. This method is based on a Dynamically-Displaced Height-map and on the numerical solutions, obtained using an Euler method, of a modified drift-diffusion equation. The method allows objects to interact with the terrain and to deform it in real time, it is easy to implement and generates different kinds of realistic tracks depending on the soil composition
Self-organisation or Selfcreation? From Social Physics to Realist Dynamics
The currently fashionable theory of self-organisation has its origins in statistical physics. Many believe that the underlying physics model, which is based on inanimate systems, can be employed to explain and predict the emergence of social structures, even of history itself. Some are even convinced that it will be possible to construct a social physics to displace the social sciences. The purpose of this article is to test those claims by reviewing some of the physical studies that have been made of human society, and its conclusion is that those claims cannot be substantiated. The underlying problem is that self-organisation is a one-dimensional theoretical concept that focuses exclusively upon supply-side interactions, from which order and complexity are said to ‘emerge’. But there is a better way. By systematic observation of living systems, both human and non-human, it has been possible to derive a general dynamic theory that embraces a more complex reality, involving a creative exchange between decision-making individuals and the changing needs of their society. I have called this interaction between the dynamic forces of demand and supply in living systems, the process of ‘strategic exchange’. And it is this strategic exchange that determines all other structural relationships in society, including the interaction between its constituent members. It is important in the social sciences, therefore, to move on from social physics to realist dynamics.agent-based modelling, complexity theory, dynamic-strategy theory, power laws, realist dynamics, self-organised criticality, Snooks-Panov algorithm, social physics, strategic demand
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A framework for local terrain deformation based on diffusion theory
Terrains have a key role in making outdoor virtual scenes believable and immersive as they form the support for every other natural element in the scene. Although important, terrains are often given limited interactivity in real-time applications. However, in nature, terrains are dynamic and interact with the rest of the environment changing shape on different levels, from tracks left by a person running on a gravel soil (micro-scale), to avalanches on the side of a mountain (macro-scale).
The challenge in representing dynamic terrains correctly is that the soil that forms them is vastly heterogeneous and behaves differently depending on its composition. This heterogeneity introduces difficulties at different levels in dynamic terrains simulations, from modelling the large amount of different elements that compose the oil to simulating their dynamic behaviour.
This work presents a novel framework to simulate multi-material dynamic terrains by taking into account the soil composition and its heterogeneity. In the proposed framework soil information is obtained from a material description map applied to the terrain mesh. This information is used to compute deformations in the area of interaction using a novel mathematical model based on diffusion theory. The deformations are applied to the terrain mesh in different ways depending on the distance of the area of interaction from the camera and the soil material. Deformations away from the camera are simulated by dynamically displacing normals. While deformations in a neighbourhood of the camera are represented by displacing the terrain mesh, which is locally tessellated to better fit the displacement. For gravel based soils the terrain details are added near the camera by reconstructing the meshes of the small rocks from the texture image, thus simulating both micro and macro-structure of the terrain.
The outcome of the framework is a realistic interactive dynamic terrain animation in real-time
Towards Autonomous Grading In The Real World
In this work, we aim to tackle the problem of autonomous grading, where a
dozer is required to flatten an uneven area. In addition, we explore methods
for bridging the gap between a simulated environment and real scenarios. We
design both a realistic physical simulation and a scaled real prototype
environment mimicking the real dozer dynamics and sensory information. We
establish heuristics and learning strategies in order to solve the problem.
Through extensive experimentation, we show that although heuristics are capable
of tackling the problem in a clean and noise-free simulated environment, they
fail catastrophically when facing real world scenarios. As the heuristics are
capable of successfully solving the task in the simulated environment, we show
they can be leveraged to guide a learning agent which can generalize and solve
the task both in simulation and in a scaled prototype environment.Comment: 7 pages, Accepted to IEEE-IROS202
Assessing load transfer mechanism in CMC-supported embankments adopting Timoshenko beam theory
© The authors and ICE Publishing: All rights reserved, 2015. Controlled modulus columns (CMC) supported embankments are increasingly being used for construction of major highway embankments on expansive soils particularly near waterways or coastal regions. CMC is a faster, sustainable and economical ground improvement technology that stiffens the poor soil and transmits the load from the traffic to a lower bearing stratum. The key influencing elements of the load transfer mechanism include embankment fill, load transfer platform (LTP), CMC and the underlying soils. Use of LTP enhances the load distribution mechanism in the CMC improved soft ground and minimises the post construction settlement of the ground. In this paper, reinforced Timoshenko beam theory is introduced to simulate the LTP with one layer of geosynthetics resting on CMC improved soft soil. A parametric study is conducted to investigate the importance of the height of the embankment on the maximum settlement of the LTP, tension developed in the geosynthetics and stress concentration ratio (the ratio of the stresses acting on CMC and soft soils) for the CMC supported embankments. Special attention is given to the stiffness of soft soil and shear stiffness of the geosynthetic layer. It has been observed that height of the embankment, the stiffness of the soft soil and the shear stiffness of the geosynthetics significantly influence the maximum settlement of the LTP and the stress concentration ratio
Simulating large volumes of granular matter
Master of ScienceDepartment of Computer ScienceDaniel AndresenModern techniques for simulating granular matter can produce excellent quality simulations, but usually involve a great enough performance cost to render them ineffective for real time applications. This leaves something to be desired for low-cost systems and interactive simulations which are more forgiving to inaccurate simulations, but much more strict in regards to the performance of the simulation itself. What follows is a proposal for a method of simulating granular matter that could potentially support millions of particles and several types for each particle while maintaining acceptable frame rates on consumer level hardware. By leveraging the power of consumer level graphics cards, effective data representation, and a model built around Cellular Automata a simulation can be run in real time
Self-organisation or Selfcreation? From Social Physics to Realist Dynamics
The currently fashionable theory of self-organisation has its origins in statistical physics.
Many believe that the underlying physics model, which is based on inanimate systems,
can be employed to explain and predict the emergence of social structures, even of
history itself. Some are even convinced that it will be possible to construct a social
physics to displace the social sciences. The purpose of this article is to test those claims
by reviewing some of the physical studies that have been made of human society, and its
conclusion is that those claims cannot be substantiated. The underlying problem is that
self-organisation is a one-dimensional theoretical concept that focuses exclusively upon
supply-side interactions, from which order and complexity are said to ‘emerge’. But there
is a better way. By systematic observation of living systems, both human and non-human,
it has been possible to derive a general dynamic theory that embraces a more complex
reality, involving a creative exchange between decision-making individuals and the
changing needs of their society. I have called this interaction between the dynamic forces
of demand and supply in living systems, the process of ‘strategic exchange’. And it is this
strategic exchange that determines all other structural relationships in society, including
the interaction between its constituent members. It is important in the social sciences,
therefore, to move on from social physics to realist dynamics
Modeling the natural freezeback of piles using COMSOL Multiphysics®
Thesis (M.S.) University of Alaska Fairbanks, 2017Slurried pile foundations installed in predrilled holes are one of the most common foundations for building major structures on permafrost. This installation method relies on the cold permafrost to freeze the backfilled slurry around the piles to provide the strength required to support loads of a structure. Nearly all evaluations of freezeback time to date stems from the work of Frederick Crory presented to the First International Conference on Permafrost in 1963 and published in 1966. Crory never published field data but he provided an equation to determine freezeback time. This work was later expanded upon by G.H. Johnston in 1981 however Johnston gives no explanation for how or why he varied from what Crory had done. The purpose of this research is to check the results predicted by both Crory and Johnston with a contemporary computer modeling using COMSOL ® Multiphysics. Due to the advancement in technology and the power of COMSOL as a program more variables and situations will be able to be examined than what was available to Crory or Johnston at the times of their publications. This will be the first research in over 50 years to revise the work first published by Crory and show that his equation produces results that are significantly shorter than what the model calculates
Proceedings of the 18th UK Travelling Workshop:GeoMechanics: from Micro to Macro (GM3), Dundee, 2021
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