Coaction across multiple behaviors with veterans

We investigate whether standard evolutionary robotics methods can be extended to support the evolution of multiple behaviors by forcing the retention of variations that are adaptive with respect to all required behaviors. This is realized by selecting the individuals located in the first Pareto fronts of the multidimensional fitness space in the case of a standard evolutionary algorithms and by computing and using multiple gradients of the expected fitness in the case of a modern evolutionary strategies that move the population in the direction of the gradient of the fitness. The results collected on two extended versions of state-of-the-art benchmarking problems indicate that the latter method permits to evolve robots capable of producing the required multiple behaviors in the majority of the replications and produces significantly better results than all the other methods considered.

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Search Patterns Based on Trajectories Extracted from the Response of Second-Order Systems

Applied Sciences ◽

10.3390/app11083430 ◽

2021 ◽

Vol 11 (8) ◽

pp. 3430

Author(s):

Erik Cuevas ◽

Héctor Becerra ◽

Héctor Escobar ◽

Alberto Luque-Chang ◽

Marco Pérez ◽

...

Keyword(s):

Convergence Rates ◽

Optimization Problems ◽

Search Space ◽

Second Order ◽

Order System ◽

Search Patterns ◽

Multiple Behaviors ◽

Complex Optimization ◽

Second Order Systems ◽

Order Algorithm

Recently, several new metaheuristic schemes have been introduced in the literature. Although all these approaches consider very different phenomena as metaphors, the search patterns used to explore the search space are very similar. On the other hand, second-order systems are models that present different temporal behaviors depending on the value of their parameters. Such temporal behaviors can be conceived as search patterns with multiple behaviors and simple configurations. In this paper, a set of new search patterns are introduced to explore the search space efficiently. They emulate the response of a second-order system. The proposed set of search patterns have been integrated as a complete search strategy, called Second-Order Algorithm (SOA), to obtain the global solution of complex optimization problems. To analyze the performance of the proposed scheme, it has been compared in a set of representative optimization problems, including multimodal, unimodal, and hybrid benchmark formulations. Numerical results demonstrate that the proposed SOA method exhibits remarkable performance in terms of accuracy and high convergence rates.

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Multiple Behaviors Generation by 1 D.O.F. Mobile Robot

2009 IEEE Virtual Reality Conference ◽

10.1109/vr.2009.4811069 ◽

2009 ◽

Author(s):

Teppei Toyoizumi ◽

Shogo Yonekura ◽

Riichiro Tadakuma ◽

Yoichiro Kawaguchi ◽

Akiya Kamimura

Keyword(s):

Mobile Robot ◽

Multiple Behaviors

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COVID-19-related psychological distress and engagement in preventative behaviors among individuals with severe mental illnesses

npj Schizophrenia ◽

10.1038/s41537-021-00136-5 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Amy E. Pinkham ◽

Robert A. Ackerman ◽

Colin A. Depp ◽

Philip D. Harvey ◽

Raeanne C. Moore

Keyword(s):

Psychological Distress ◽

Affective Disorders ◽

Diagnostic Category ◽

Mental Illnesses ◽

Large Majority ◽

The Past ◽

Schizophrenia Spectrum ◽

Phone Survey ◽

Multiple Behaviors ◽

And Coping

AbstractIndividuals with severe mental illnesses (SMIs) may be disproportionately vulnerable to COVID-19 infection and psychological distress. This study investigated the prevalence of engagement in COVID-19 preventative behaviors, predictors of these behaviors, and COVID-19-related psychological distress. One hundred and sixty-three individuals with SMIs (94 with schizophrenia spectrum illnesses and 69 with affective disorders) and 27 psychiatrically healthy comparison participants were recruited from ongoing studies across 3 sites, to complete a phone survey querying implementation of 8 specific COVID-19 preventative behaviors that participants engaged in at least once in the past month as well as standard assessments of depression, anxiety, perceived stress, loneliness, and coping. Data were collected between 3 April 2020 and 4 June 2020. The large majority of our SMI sample, which consisted of outpatients with relatively mild symptom severity, endorsed engaging in multiple preventative behaviors. Relatively few differences were found between groups; however, individuals with SMI were less likely to work remotely than healthy individuals and individuals with schizophrenia spectrum illness were less likely to stay home as a preventative measure, wear face masks, and work remotely than individuals with affective disorders. Differences in staying home remained after controlling for potential confounds. Although individuals with SMI reported more psychological distress related to COVID-19, this distress was largely unrelated to engagement in preventative behaviors. The large majority of individuals with SMI in this outpatient sample, regardless of broad diagnostic category, reported performing multiple behaviors intended to prevent COVID-19 infection at least once a month and reported distress associated with the pandemic. These findings suggest a good level of awareness of COVID-19 among stable outpatients with SMI. The degree to which more acutely ill persons with SMI engage in such preventative behaviors, however, remains to be examined.

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SIPEC: the deep-learning Swiss knife for behavioral data analysis

10.1101/2020.10.26.355115 ◽

2020 ◽

Author(s):

Markus Marks ◽

Jin Qiuhan ◽

Oliver Sturman ◽

Lukas von Ziegler ◽

Sepp Kollmorgen ◽

...

Keyword(s):

Deep Learning ◽

Pose Estimation ◽

Animal Behavior ◽

Home Cage ◽

Complex Environments ◽

Or Groups ◽

Multiple Behaviors ◽

Freely Moving ◽

Using Data

ABSTRACTAnalysing the behavior of individuals or groups of animals in complex environments is an important, yet difficult computer vision task. Here we present a novel deep learning architecture for classifying animal behavior and demonstrate how this end-to-end approach can significantly outperform pose estimation-based approaches, whilst requiring no intervention after minimal training. Our behavioral classifier is embedded in a first-of-its-kind pipeline (SIPEC) which performs segmentation, identification, pose-estimation and classification of behavior all automatically. SIPEC successfully recognizes multiple behaviors of freely moving mice as well as socially interacting nonhuman primates in 3D, using data only from simple mono-vision cameras in home-cage setups.

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The slip behavior of velocity-weakening fault barriers

10.5194/egusphere-egu21-7752 ◽

2021 ◽

Author(s):

Diego Molina ◽

Jean-Paul Ampuero ◽

Andres Tassara

Keyword(s):

Fracture Energy ◽

Normal Stress ◽

Seismic Hazard Assessment ◽

Large Earthquake ◽

Earthquake Scenarios ◽

Structural Controls ◽

Frictional Properties ◽

Geological Features ◽

Rate And State Friction ◽

Multiple Behaviors

Subduction earthquakes are among the most devastating natural hazards across the planet and yet the factors controlling their size remain poorly understood. It is thus important to investigate the mechanisms controlling rupture arrest and runaway, in particular the nature of rupture barriers (areas where earthquakes tend to stop). Geodetic and seismic observations along several faults suggest that barriers are mostly creeping (low seismic coupling). It is often interpreted that creeping barriers are governed by velocity-strengthening friction (VS), which is a sufficient condition for stable slip. However, some barriers have been observed to host intermediate magnitude earthquakes or to be completely ruptured by a large earthquake. Therefore, the frictional properties of seismic barriers may not be restricted to VS. In particular, the possibility of velocity-weakening (VW) areas behaving as barriers needs to be further explored.In this work, we characterize the multiple behaviors of seismic barriers on faults governed by velocity-weakening (VW) rate-and-state friction, using earthquake cycle simulations. We consider a 2D model, where a central VW area has a larger critical slip distance (Dc) or higher normal stress (&#963;) than the surrounding VW areas. We found that the central areas can behave as permanent or temporal barriers to earthquake propagation if their Dc or &#963; are large enough. On permanent barriers, creep occurs steadily. However, on temporary barriers, the locking degree changes throughout the cycle, despite frictional properties remaining constant.To understand the efficiency of VW barriers (that is, to determine under what conditions they can stop ruptures), we use fracture mechanics theory. We found that barrier efficiency depends mainly on the ratio between the fracture energy of the barrier, which is proportional to Dc and normal stress, and the energy release rate of the neighboring seismic segment, which is proportional to its stress drop squared and length. If geological features of the overriding and subducting plates affect Dc and &#963; on the megathrust, our results support the idea of structural controls on the seismic behavior of megathrusts. Thus, understanding how geological features are linked to fracture energy may contribute to seismic hazard assessment by constraining rupture arrest and multi-segment ruptures in earthquake scenarios.

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Central pattern generators in the turtle spinal cord: selection among the forms of motor behaviors

Journal of Neurophysiology ◽

10.1152/jn.00602.2017 ◽

2018 ◽

Vol 119 (2) ◽

pp. 422-440 ◽

Cited By ~ 9

Author(s):

Paul S. G. Stein

Keyword(s):

Spinal Cord ◽

Motor Pattern ◽

Central Pattern Generators ◽

Knee Extensor ◽

Motor Patterns ◽

Motor Behaviors ◽

Multiple Behaviors ◽

Pattern Generators ◽

Electrical Stimuli

Neuronal networks in the turtle spinal cord have considerable computational complexity even in the absence of connections with supraspinal structures. These networks contain central pattern generators (CPGs) for each of several behaviors, including three forms of scratch, two forms of swim, and one form of flexion reflex. Each behavior is activated by a specific set of cutaneous or electrical stimuli. The process of selection among behaviors within the spinal cord has multisecond memories of specific motor patterns. Some spinal cord interneurons are partially shared among several CPGs, whereas other interneurons are active during only one type of behavior. Partial sharing is a proposed mechanism that contributes to the ability of the spinal cord to generate motor pattern blends with characteristics of multiple behaviors. Variations of motor patterns, termed deletions, assist in characterization of the organization of the pattern-generating components of CPGs. Single-neuron recordings during both normal and deletion motor patterns provide support for a CPG organizational structure with unit burst generators (UBGs) whose members serve a direction of a specific degree of freedom of the hindlimb, e.g., the hip-flexor UBG, the hip-extensor UBG, the knee-flexor UBG, the knee-extensor UBG, etc. The classic half-center hypothesis that includes all the hindlimb flexors in a single flexor half-center and all the hindlimb extensors in a single extensor half-center lacks the organizational complexity to account for the motor patterns produced by turtle spinal CPGs. Thus the turtle spinal cord is a valuable model system for studies of mechanisms responsible for selection and generation of motor behaviors. NEW & NOTEWORTHY The concept of the central pattern generator (CPG) is a major tenet in motor neuroethology that has influenced the design and interpretations of experiments for over a half century. This review concentrates on the turtle spinal cord and describes studies from the 1970s to the present responsible for key developments in understanding the CPG mechanisms responsible for the selection and production of coordinated motor patterns during turtle hindlimb motor behaviors.

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Behavioral diversity is maintained by a conditional strategy in a freshwater zooplankton

Behavioral Ecology ◽

10.1093/beheco/arz041 ◽

2019 ◽

Vol 30 (4) ◽

pp. 1001-1011

Author(s):

G Adam Meyer ◽

William A Nelson

Keyword(s):

Population Growth ◽

Intraspecific Diversity ◽

Migration Behavior ◽

Ecological Strategy ◽

Conditional Strategy ◽

Freshwater Zooplankton ◽

Behavioral Diversity ◽

Behavioral Switching ◽

Alternative Behaviors ◽

Multiple Behaviors

Abstract Many populations have intraspecific diversity in phenotype and ecological strategy, but the mechanisms maintaining such diversity are not fully understood. Multiple behaviors can be maintained either as a conditional strategy, where fitness depends on an individual’s phenotype, or as a mixed strategy, where alternative behaviors have similar fitness independent of phenotype. Using high-resolution depth and time sampling, we characterize 2 distinct diel vertical migration behaviors in a population of freshwater zooplankton (Daphnia pulicaria). Individuals in this population differ in their color phenotype and migratory behavior with red morphs upregulating hemoglobin and undergoing a deep migration and pale morphs not producing hemoglobin and undergoing a shallow migration. We experimentally manipulated the behavior of each phenotype in the field and measured population growth in their natural migration behavior as well as population growth in their alternative behaviors. Experimental populations of pale and red morphs under their natural migrations had roughly equal fitness, despite vast differences in environmental conditions. When forced to switch behaviors, pale morphs suffered reduced fitness, whereas red morphs had similar fitness compared with their natural migration. Our results suggest that although behavioral diversity may be promoted by the opportunity for alternative behaviors of equal fitness, the distinct physiological conditions required for survival in alternative behaviors limit the capacity for individual behavioral switching and likely maintain behavioral diversity as a conditional strategy.

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Optimization of Rhythmic Behaviors by Modulation of the Neuromuscular Transform

Journal of Neurophysiology ◽

10.1152/jn.2000.83.1.260 ◽

2000 ◽

Vol 83 (1) ◽

pp. 260-279 ◽

Cited By ~ 32

Author(s):

Vladimir Brezina ◽

Irina V. Orekhova ◽

Klaudiusz R. Weiss

Keyword(s):

Motor Neuron ◽

Firing Pattern ◽

Critical Role ◽

Neuron Firing ◽

Functional Behavior ◽

Rhythmic Behavior ◽

Multiple Behaviors ◽

Intrinsic Plasticity ◽

Rhythmic Behaviors

We conclude our study of the properties and the functional role of the neuromuscular transform (NMT). The NMT is an input-output relation that formalizes the processes by which patterns of motor neuron firing are transformed to muscle contractions. Because the NMT acts as a dynamic, nonlinear, and modifiable filter, the transformation is complex. In the two preceding papers we developed a framework for analysis of the NMT and identified with it principles by which the NMT transforms different firing patterns to contractions. We then saw that, with fixed properties, the NMT significantly constrains the production of functional behavior. Many desirable behaviors are not possible with any firing pattern. Here we examine, theoretically as well as experimentally in the accessory radula closer (ARC) neuromuscular system of Aplysia, how this constraint is alleviated by making the properties of the NMT variable by neuromuscular plasticity and modulation. These processes dynamically tune the properties of the NMT to match the desired behavior, expanding the range of behaviors that can be produced. For specific illustration, we continue to focus on the relation between the speed of the NMT and the speed of cyclical, rhythmic behavior. Our analytic framework emphasizes the functional distinction between intrinsic plasticity or modulation of the NMT, dependent, like the contraction itself, on the motor neuron firing pattern, and extrinsic modulation, independent of it. The former is well suited to automatically optimizing the performance of a single behavior; the latter, to multiplying contraction shapes for multiple behaviors. In any case, to alleviate the constraint of the NMT, the plasticity and modulation must be peripheral. Such processes are likely to play a critical role wherever the nervous system must command, through the constraint of the NMT, a broad range of functional behaviors.

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