scholarly journals Using collision cones to assess biological deconfliction methods

2016 ◽  
Vol 13 (122) ◽  
pp. 20160502 ◽  
Author(s):  
Natalie L. Brace ◽  
Tyson L. Hedrick ◽  
Diane H. Theriault ◽  
Nathan W. Fuller ◽  
Zheng Wu ◽  
...  
Keyword(s):  
Collision Avoidance ◽  
Relative Position ◽  
Visual Cues ◽  
Autonomous Systems ◽  
Trajectory Data ◽  
Topological Distance ◽  
Petrochelidon Pyrrhonota ◽  
Minimal Deviation ◽  
Danio Aequipinnatus ◽  
Good Agreement

Biological systems consistently outperform autonomous systems governed by engineered algorithms in their ability to reactively avoid collisions. To better understand this discrepancy, a collision avoidance algorithm was applied to frames of digitized video trajectory data from bats, swallows and fish ( Myotis velifer , Petrochelidon pyrrhonota and Danio aequipinnatus ). Information available from visual cues, specifically relative position and velocity, was provided to the algorithm which used this information to define collision cones that allowed the algorithm to find a safe velocity requiring minimal deviation from the original velocity. The subset of obstacles provided to the algorithm was determined by the animal's sensing range in terms of metric and topological distance. The algorithmic calculated velocities showed good agreement with observed biological velocities, indicating that the algorithm was an informative basis for comparison with the three species and could potentially be improved for engineered applications with further study.

Collective Response of Zebrafish to a Mobile Robotic Fish

2013 ◽  
Author(s):  
Sachit Butail ◽  
Tiziana Bartolini ◽  
Maurizio Porfiri
Keyword(s):  
Visual Cues ◽  
Color Pattern ◽  
The Body ◽  
Robotic Fish ◽  
Steering Control ◽  
Trajectory Data ◽  
Experimental Conditions ◽  
Collective Response ◽  
Multi Target Tracking ◽  
Social Organism

We investigate the response of groups of zebrafish, a model social organism, to a free-swimming robotic fish. The robot has a body and tail section and moves forward by beating the tail. Steering control is achieved by offsetting the beating tail with respect to the body. The color pattern and shape of the robot are informed by visual cues known to be preferred by zebrafish. A real-time multi-target tracking algorithm uses position and velocity estimates to autonomously maneuver the robot in circular trajectories. Observables of collective behavior are computed from the fish trajectory data to measure cohesiveness, polarization, and speed of the zebrafish group in two different experimental conditions. We show that while fish are significantly less polarized in the presence of the robot with an accompanying change in average speed, there is no significant change in the degree of cohesion.

Guaranteed Collision Avoidance for Autonomous Systems with Acceleration Constraints and Sensing Uncertainties

2015 ◽  
Vol 168 (3) ◽  
pp. 1014-1038 ◽  
Author(s):  
Erick J. Rodríguez-Seda ◽  
Dušan M. Stipanović ◽  
Mark W. Spong
Keyword(s):  
Collision Avoidance ◽  
Autonomous Systems

scholarly journals Simulation of Pedestrian Behavior in the Collision-Avoidance Process considering Their Moving Preferences

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Zhilu Yuan ◽  
Hongfei Jia ◽  
Linfeng Zhang ◽  
Lei Bian
Keyword(s):  
Collision Avoidance ◽  
Relative Position ◽  
Hand Preference ◽  
The Self ◽  
Force Model ◽  
Pedestrian Flow ◽  
Social Force ◽  
Potential Conflict ◽  
Improved Model ◽  
Self Organizing

Walking habits can affect the self-organizing movement in pedestrian flow. In China, pedestrians prefer to walk along the right-hand side in the collision-avoidance process, and the same is true for the left-hand preference that is followed in several countries. Through experiments with pedestrian flow, we find that the relative position between pedestrians can affect their moving preferences. We propose a kind of collision-avoidance force based on the social force model, which considers the predictions of potential conflict and the relative position between pedestrians. In the simulation, we use the improved model to explore the effect of moving preference on the collision-avoidance process and self-organizing pedestrian movement. We conclude that the improved model can bring the simulation closer to reality and that moving preference is conducive to the self-adjustment of counterflow.

scholarly journals Bridging microscopic and macroscopic mechanisms of p53-MDM2 binding using molecular simulations and kinetic network models

2016 ◽  
Author(s):  
Guangfeng Zhou ◽  
George A. Pantelopulos ◽  
Sudipto Mukherjee ◽  
Vincent A. Voelz
Keyword(s):  
Tumor Suppressor ◽  
Molecular Mechanisms ◽  
Network Models ◽  
Tumor Suppressor Protein ◽  
Transactivation Domain ◽  
Trajectory Data ◽  
Tumor Suppressor Protein P53 ◽  
Intrinsically Disordered ◽  
Protein P53 ◽  
Good Agreement

Under normal cellular conditions, the tumor suppressor protein p53 is kept at a low levels in part due to ubiquitination by MDM2, a process initiated by binding of MDM2 to the intrinsically disordered transactivation domain (TAD) of p53. Although many experimental and simulation studies suggest that disordered domains such as p53 TAD bind their targets nonspecifically before folding to a tightly-associated conformation, the molecular details are unclear. Toward a detailed prediction of binding mechanism, pathways and rates, we have performed large-scale unbiased all-atom simulations of p53-MDM2 binding. Markov State Models (MSMs) constructed from the trajectory data predict p53 TAD peptide binding pathways and on-rates in good agreement with experiment. The MSM reveals that two key bound intermediates, each with a non-native arrangement of hydrophobic residues in the MDM2 binding cleft, control the overall on-rate. Using microscopic rate information from the MSM, we parameterize a simple four-state kinetic model to (1) determine that induced-fit pathways dominate the binding flux over a large range of concentrations, and (2) predict how modulation of residual p53 helicity affects binding, in good agreement with experiment. These results suggest new ways in which microscopic models of bound-state ensembles can be used to understand biological function on a macroscopic scale.AUTHOR SUMMARYMany cell signaling pathways involve protein-protein interactions in which an intrinsically disordered peptide folds upon binding its target. Determining the molecular mechanisms that control these binding rates is important for understanding how such systems are regulated. In this paper, we show how extensive all-atom simulations combined with kinetic network models provide a detailed mechanistic understanding of how tumor suppressor protein p53 binds to MDM2, an important target of new cancer therapeutics. A simple four-state model parameterized from the simulations shows a binding-then-folding mechanism, and recapitulates experiments in which residual helicity boosts binding. This work goes beyond previous simulations of small-molecule binding, to achieve pathways and binding rates for a large peptide, in good agreement with experiment.

scholarly journals PERSPECTIVE METHODS OF DIVERGENCE OF VESSELS AND ANALYSIS OF THEIR EFFICIENCY

2020 ◽  
Vol 1 (22) ◽  
pp. 54-63
Author(s):  
Yu. M. Khussein ◽  
◽  
O. V. Yanchetskyy ◽  
Keyword(s):  
Decision Making ◽  
Collision Avoidance ◽  
Relative Motion ◽  
Relative Position ◽  
Preliminary Analysis ◽  
Decision Making Process ◽  
Rule Application ◽  
The Moment ◽  
Analytical Expressions

The article is devoted to the analysis of the most perspective and effective locally-independent methods of divergence of vessels for forming of the system of the automatic warning of collisions, providing safety of perspective autonomous vessels. Development of method of estimation of efficiency of methods of divergence of vessels, which characterizes the degree of safety of completion of process of divergence of vessels, is offered, since the moment of discovery of situation of dangerous rapprochement. The stages of process of decision-making divergence of vessels of necessity are considered at their rapprochement and choice of strategy of divergence. It is shown that a decision-making process contains the following stages: control of environment, including relative position and parameters of relative motion, exposure of situation of rapprochement of vessels, estimation of degree of danger of rapprochement and choice of strategy of divergence. Analytical expressions for formalization of the offered stages of process of decision-making divergence of vessels of necessity are resulted. It is shown that depending on the degree of danger of situation of rapprochement, it is necessary to choose strategy of divergence, coming co-ordination of maneuvers of the drawn together vessels from, foreseen ColReg. Thus character of maneuver of divergence is also determined by the value of situation indignation. As a rule, application of standard maneuver of divergence is foreseen, and in the situation of excessive rapprochement of vessels, in order to avoid the collision it is necessary to use the maneuver of urgent divergence. As the index of efficiency of the analytical collision avoidance systems vessels probability of safe completion of process of divergence, which is work of probabilities of successful finish of stages of process of decision-making on the choice of strategy of divergence, is offered. For the system of the automatic warning of collisions the methods of divergence with one dangerous target are offered by the change of course or speed of ship and with two dangerous targets by the combined maneuver of the repeated change of course of ship. After the preliminary analysis the perspective most effective methods of the mentioned types of maneuvers of divergence were offered. For the operative choice of parameters of maneuver of divergence of ship with a target the regions of impermissible values of parameters of deviation and region of acceptability parameters of deviation and output are offered. For the case of choice of maneuver of divergence of ship by the decline of speed the active or passive braking offers the method of forming of region of impermissible speeds and calculation of its scopes. In the situation of dangerous rapprochement of ship with two targets for the operative choice of parameters of maneuver of divergence of ship in work it is suggested to form the region of acceptability successive courses of deviation.

scholarly journals Advanced models for centroidal particle dynamics: short-range collision avoidance in dense crowds

SIMULATION ◽  
2021 ◽  
pp. 003754972110031
Author(s):  
Omar Hesham ◽  
Gabriel Wainer
Keyword(s):  
Collision Avoidance ◽  
State Of The Art ◽  
Threat Assessment ◽  
Personal Space ◽  
Particle Dynamics ◽  
Emergent Behavior ◽  
Trajectory Data ◽  
Agent Based ◽  
Dense Crowds ◽  
Dense Crowd

Computer simulation of dense crowds is finding increased use in event planning, congestion prediction, and threat assessment. State-of-the-art particle-based crowd methods assume and aim for collision-free trajectories. That is an idealistic yet not overly realistic expectation, as near-collisions increase in dense and rushed settings compared with typically sparse pedestrian scenarios. Centroidal particle dynamics (CPD) is a method we defined that explicitly models the compressible personal space area surrounding each entity to inform its local pathing and collision-avoidance decisions. We illustrate how our proposed agent-based method for local dynamics can reproduce several key emergent dense crowd phenomena at the microscopic level with higher congruence to real trajectory data and with more visually convincing collision-avoidance paths than the existing state of the art. We present advanced models in which we consider distraction of the pedestrians in the crowd, flocking behavior, interaction with vehicles (ambulances, police) and other advanced models that show that emergent behavior in the simulated crowds is similar to the behavior observed in reality. We discuss how to increase confidence in CPD, potentially making it also suitable for use in safety-critical applications, including urban design, evacuation analysis, and crowd-safety planning.

scholarly journals Belief Propagation in Networks of Spiking Neurons

2009 ◽  
Vol 21 (9) ◽  
pp. 2502-2523 ◽  
Author(s):  
Andreas Steimer ◽  
Wolfgang Maass ◽  
Rodney Douglas
Keyword(s):  
Coding Theory ◽  
Numerical Evaluation ◽  
Visual Cues ◽  
Belief Propagation ◽  
Point Of View ◽  
Spiking Neurons ◽  
Factor Graph ◽  
Theoretical Point ◽  
Belief Propagation Algorithm ◽  
Good Agreement

From a theoretical point of view, statistical inference is an attractive model of brain operation. However, it is unclear how to implement these inferential processes in neuronal networks. We offer a solution to this problem by showing in detailed simulations how the belief propagation algorithm on a factor graph can be embedded in a network of spiking neurons. We use pools of spiking neurons as the function nodes of the factor graph. Each pool gathers “messages” in the form of population activities from its input nodes and combines them through its network dynamics. Each of the various output messages to be transmitted over the edges of the graph is computed by a group of readout neurons that feed in their respective destination pools. We use this approach to implement two examples of factor graphs. The first example, drawn from coding theory, models the transmission of signals through an unreliable channel and demonstrates the principles and generality of our network approach. The second, more applied example is of a psychophysical mechanism in which visual cues are used to resolve hypotheses about the interpretation of an object's shape and illumination. These two examples, and also a statistical analysis, demonstrate good agreement between the performance of our networks and the direct numerical evaluation of belief propagation.

scholarly journals A fast three-dimensional deterministic ray tracing coverage simulator for a 24 GHz anti-collision radar

2013 ◽  
Vol 11 ◽  
pp. 55-60 ◽  
Author(s):  
H. Azodi ◽  
U. Siart ◽  
T. F. Eibert
Keyword(s):  
Integral Equation ◽  
Ray Tracing ◽  
Collision Avoidance ◽  
Electromagnetic Fields ◽  
Method Of Moments ◽  
Three Dimensional ◽  
Frequency Independent ◽  
The Matrix ◽  
24 Ghz ◽  
Good Agreement

Abstract. A matrix-based approach for implementation of deterministic ray tracing is suggested and presented in this paper. The frequency-independent feature of the ray tracing in addition to the matrix-based implementation results in a reliable fast simulator for understanding the behavior of the electromagnetic fields in the vicinity of a collision avoidance radar. Results of this technique are in a good agreement with the results from method of moments integral equation solutions while the computations are about 100 times faster.

scholarly journals Autonomous Collision Avoidance at Sea: A Survey

2021 ◽  
Vol 8 ◽  
Author(s):  
Hans-Christoph Burmeister ◽  
Manfred Constapel
Keyword(s):  
Artificial Intelligence ◽  
Machine Learning ◽  
Decision Support ◽  
Collision Avoidance ◽  
Data Science ◽  
Autonomous Systems ◽  
Data Driven ◽  
Comprehensive Overview ◽  
Planning Methods ◽  
Survey Results

In this survey, results from an investigation on collision avoidance and path planning methods developed in recent research are provided. In particular, existing methods based on Artificial Intelligence, data-driven methods based on Machine Learning, and other Data Science approaches are investigated to provide a comprehensive overview of maritime collision avoidance techniques applicable to Maritime Autonomous Surface Ships. Relevant aspects of those methods and approaches are summarized and put into suitable perspectives. As autonomous systems are expected to operate alongside or in place of conventionally manned vessels, they must comply with the COLREGs for robust decision-support/-making. Thus, the survey specifically covers how COLREGs are addressed by the investigated methods and approaches. A conclusion regarding their utilization in industrial implementations is drawn.

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