1,140 research outputs found
A Growth model for DNA evolution
A simple growth model for DNA evolution is introduced which is analytically
solvable and reproduces the observed statistical behavior of real sequences.Comment: To be published in Europhysics Letter
A simple deterministic self-organized critical system
We introduce a new continuous cellular automaton that presents self-organized
criticality. It is one-dimensional, totally deterministic, without any kind of
embedded randomness, not even in the initial conditions. This system is in the
same universality class as the Oslo rice pile system, boundary driven interface
depinning and the train model for earthquakes. Although the system is chaotic,
in the thermodynamic limit chaos occurs only in a microscopic level.Comment: System slightly modified. New results on Liapunov exponents.
Submitted for publication (8 pages
Chaos and Synchronized Chaos in an Earthquake Model
We show that chaos is present in the symmetric two-block Burridge-Knopoff
model for earthquakes. This is in contrast with previous numerical studies, but
in agreement with experimental results. In this system, we have found a rich
dynamical behavior with an unusual route to chaos. In the three-block system,
we see the appearance of synchronized chaos, showing that this concept can have
potential applications in the field of seismology.Comment: To appear in Physical Review Letters (13 pages, 6 figures
Self-Similarity of Friction Laws
The change of the friction law from a mesoscopic level to a macroscopic level
is studied in the spring-block models introduced by Burridge-Knopoff. We find
that the Coulomb law is always scale invariant. Other proposed scaling laws are
only invariant under certain conditions.}Comment: Plain TEX. Figures not include
Exponential Distributions in a Mechanical Model for Earthquakes
We study statistical distributions in a mechanical model for an earthquake
fault introduced by Burridge and Knopoff [R. Burridge and L. Knopoff, {\sl
Bull. Seismol. Soc. Am.} {\bf 57}, 341 (1967)]. Our investigations on the size
(moment), time duration and number of blocks involved in an event show that
exponential distributions are found in a given range of the paramenter space.
This occurs when the two kinds of springs present in the model have the same,
or approximately the same, value for the elastic constants. Exponential
distributions have also been seen recently in an experimental system to model
earthquake-like dynamics [M. A. Rubio and J. Galeano, {\sl Phys. Rev. E} {\bf
50}, 1000 (1994)].Comment: 11 pages, uuencoded (submitted to Phys. Rev. E
New strategies for pine wilt disease (PWD) management in Portugal: preventive methods to reduce the spread of the disease to new areas
Deep Learning Models to Predict Finishing Pig Weight Using Point Clouds
The selection of animals to be marketed is largely completed by their visual assessment, solely relying on the skill level of the animal caretaker. Real-time monitoring of the weight of farm animals would provide important information for not only marketing, but also for the assessment of health and well-being issues. The objective of this study was to develop and evaluate a method based on 3D Convolutional Neural Network to predict weight from point clouds. Intel Real Sense D435 stereo depth camera placed at 2.7 m height was used to capture the 3D videos of a single finishing pig freely walking in a holding pen ranging in weight between 20–120 kg. The animal weight and 3D videos were collected from 249 Landrace × Large White pigs in farm facilities of the FZEA-USP (Faculty of Animal Science and Food Engineering, University of Sao Paulo) between 5 August and 9 November 2021. Point clouds were manually extracted from the recorded 3D video and applied for modeling. A total of 1186 point clouds were used for model training and validating using PointNet framework in Python with a 9:1 split and 112 randomly selected point clouds were reserved for testing. The volume between the body surface points and a constant plane resembling the ground was calculated and correlated with weight to make a comparison with results from the PointNet method. The coefficient of determination (R2 = 0.94) was achieved with PointNet regression model on test point clouds compared to the coefficient of determination (R2 = 0.76) achieved from the volume of the same animal. The validation RMSE of the model was 6.79 kg with a test RMSE of 6.88 kg. Further, to analyze model performance based on weight range the pigs were divided into three different weight ranges: below 55 kg, between 55 and 90 kg, and above 90 kg. For different weight groups, pigs weighing below 55 kg were best predicted with the model. The results clearly showed that 3D deep learning on point sets has a good potential for accurate weight prediction even with a limited training dataset. Therefore, this study confirms the usability of 3D deep learning on point sets for farm animals’ weight prediction, while a larger data set needs to be used to ensure the most accurate predictions
Deep Learning Models to Predict Finishing Pig Weight Using Point Clouds
The selection of animals to be marketed is largely completed by their visual assessment, solely relying on the skill level of the animal caretaker. Real-time monitoring of the weight of farm animals would provide important information for not only marketing, but also for the assessment of health and well-being issues. The objective of this study was to develop and evaluate a method based on 3D Convolutional Neural Network to predict weight from point clouds. Intel Real Sense D435 stereo depth camera placed at 2.7 m height was used to capture the 3D videos of a single finishing pig freely walking in a holding pen ranging in weight between 20–120 kg. The animal weight and 3D videos were collected from 249 Landrace × Large White pigs in farm facilities of the FZEA-USP (Faculty of Animal Science and Food Engineering, University of Sao Paulo) between 5 August and 9 November 2021. Point clouds were manually extracted from the recorded 3D video and applied for modeling. A total of 1186 point clouds were used for model training and validating using PointNet framework in Python with a 9:1 split and 112 randomly selected point clouds were reserved for testing. The volume between the body surface points and a constant plane resembling the ground was calculated and correlated with weight to make a comparison with results from the PointNet method. The coefficient of determination (R2 = 0.94) was achieved with PointNet regression model on test point clouds compared to the coefficient of determination (R2 = 0.76) achieved from the volume of the same animal. The validation RMSE of the model was 6.79 kg with a test RMSE of 6.88 kg. Further, to analyze model performance based on weight range the pigs were divided into three different weight ranges: below 55 kg, between 55 and 90 kg, and above 90 kg. For different weight groups, pigs weighing below 55 kg were best predicted with the model. The results clearly showed that 3D deep learning on point sets has a good potential for accurate weight prediction even with a limited training dataset. Therefore, this study confirms the usability of 3D deep learning on point sets for farm animals’ weight prediction, while a larger data set needs to be used to ensure the most accurate predictions
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