1,607 research outputs found

    Interactive Terrain Simulation and Force Distribution Models in Sand Piles

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    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

    Self-organisation or Selfcreation? From Social Physics to Realist Dynamics

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    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

    Towards Autonomous Grading In The Real World

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    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

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    © 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

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    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

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    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®

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    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
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