11,351 research outputs found
One-dimensional collision carts computer model and its design ideas for productive experiential learning
We develop an Easy Java Simulation (EJS) model for students to experience the
physics of idealized one-dimensional collision carts. The physics model is
described and simulated by both continuous dynamics and discrete transition
during collision. In the field of designing computer simulations, we discuss
briefly three pedagogical considerations such as 1) consistent simulation world
view with pen paper representation, 2) data table, scientific graphs and
symbolic mathematical representations for ease of data collection and multiple
representational visualizations and 3) game for simple concept testing that can
further support learning. We also suggest using physical world setup to be
augmented complimentary with simulation while highlighting three advantages of
real collision carts equipment like tacit 3D experience, random errors in
measurement and conceptual significance of conservation of momentum applied to
just before and after collision. General feedback from the students has been
relatively positive, and we hope teachers will find the simulation useful in
their own classes. 2015 Resources added:
http://iwant2study.org/ospsg/index.php/interactive-resources/physics/02-newtonian-mechanics/02-dynamics/46-one-dimension-collision-js-model
http://iwant2study.org/ospsg/index.php/interactive-resources/physics/02-newtonian-mechanics/02-dynamics/195-elastic-collisionComment: 6 pages, 8 figures, 1 table, 1 L. K. Wee, Physics Education 47 (3),
301 (2012); ISSN 0031-912
Machine Learning for Fluid Mechanics
The field of fluid mechanics is rapidly advancing, driven by unprecedented
volumes of data from field measurements, experiments and large-scale
simulations at multiple spatiotemporal scales. Machine learning offers a wealth
of techniques to extract information from data that could be translated into
knowledge about the underlying fluid mechanics. Moreover, machine learning
algorithms can augment domain knowledge and automate tasks related to flow
control and optimization. This article presents an overview of past history,
current developments, and emerging opportunities of machine learning for fluid
mechanics. It outlines fundamental machine learning methodologies and discusses
their uses for understanding, modeling, optimizing, and controlling fluid
flows. The strengths and limitations of these methods are addressed from the
perspective of scientific inquiry that considers data as an inherent part of
modeling, experimentation, and simulation. Machine learning provides a powerful
information processing framework that can enrich, and possibly even transform,
current lines of fluid mechanics research and industrial applications.Comment: To appear in the Annual Reviews of Fluid Mechanics, 202
Mechanical MNIST: A benchmark dataset for mechanical metamodels
Metamodels, or models of models, map defined model inputs to defined model outputs. Typically, metamodels are constructed by generating a dataset through sampling a direct model and training a machine learning algorithm to predict a limited number of model outputs from varying model inputs. When metamodels are constructed to be computationally cheap, they are an invaluable tool for applications ranging from topology optimization, to uncertainty quantification, to multi-scale simulation. By nature, a given metamodel will be tailored to a specific dataset. However, the most pragmatic metamodel type and structure will often be general to larger classes of problems. At present, the most pragmatic metamodel selection for dealing with mechanical data has not been thoroughly explored. Drawing inspiration from the benchmark datasets available to the computer vision research community, we introduce a benchmark data set (Mechanical MNIST) for constructing metamodels of heterogeneous material undergoing large deformation. We then show examples of how our benchmark dataset can be used, and establish baseline metamodel performance. Because our dataset is readily available, it will enable the direct quantitative comparison between different metamodeling approaches in a pragmatic manner. We anticipate that it will enable the broader community of researchers to develop improved metamodeling techniques for mechanical data that will surpass the baseline performance that we show here.Accepted manuscrip
Collective Motion of Predictive Swarms
Theoretical models of populations and swarms typically start with the
assumption that the motion of agents is governed by the local stimuli. However,
an intelligent agent, with some understanding of the laws that govern its
habitat, can anticipate the future, and make predictions to gather resources
more efficiently. Here we study a specific model of this kind, where agents aim
to maximize their consumption of a diffusing resource, by attempting to predict
the future of a resource field and the actions of other agents. Once the agents
make a prediction, they are attracted to move towards regions that have, and
will have, denser resources. We find that the further the agents attempt to see
into the future, the more their attempts at prediction fail, and the less
resources they consume. We also study the case where predictive agents compete
against non-predictive agents and find the predictors perform better than the
non-predictors only when their relative numbers are very small. We conclude
that predictivity pays off either when the predictors do not see too far into
the future or the number of predictors is small.Comment: 16 pages, 7 figure
The physical world as a virtual reality: a prima facie case
This paper explores the idea that the universe is a virtual reality created by information
processing, and relates this strange idea to the findings of modern physics about the physical
world. The virtual reality concept is familiar to us from online worlds, but the world as a virtual
reality is usually a subject for science fiction rather than science. Yet logically the world could be
an information simulation running on a three-dimensional space-time screen. Indeed, that the
essence of the universe is information has advantages, e.g. if matter, charge, energy and
movement are aspects of information, the many conservation laws could become a single law of
conservation of information. If the universe were a virtual reality, its creation at the big bang
would no longer be paradoxical, as every virtual system must be booted up. It is suggested that
whether the world is an objective or a virtual reality is a matter for science to resolve, and
computer science could help. If one could derive core properties like space, time, light, matter and
movement from information processing, such a model could reconcile relativity and quantum
theories, with the former being how information processing creates space-time, and the latter how
it creates energy and matter
Newtonian Image Understanding: Unfolding the Dynamics of Objects in Static Images
In this paper, we study the challenging problem of predicting the dynamics of
objects in static images. Given a query object in an image, our goal is to
provide a physical understanding of the object in terms of the forces acting
upon it and its long term motion as response to those forces. Direct and
explicit estimation of the forces and the motion of objects from a single image
is extremely challenging. We define intermediate physical abstractions called
Newtonian scenarios and introduce Newtonian Neural Network () that learns
to map a single image to a state in a Newtonian scenario. Our experimental
evaluations show that our method can reliably predict dynamics of a query
object from a single image. In addition, our approach can provide physical
reasoning that supports the predicted dynamics in terms of velocity and force
vectors. To spur research in this direction we compiled Visual Newtonian
Dynamics (VIND) dataset that includes 6806 videos aligned with Newtonian
scenarios represented using game engines, and 4516 still images with their
ground truth dynamics
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