scholarly journals Sensory modulation of gait characteristics in human locomotion: A neuromusculoskeletal modeling study

2021 ◽  
Vol 17 (5) ◽  
pp. e1008594
Author(s):  
Andrea Di Russo ◽  
Dimitar Stanev ◽  
Stéphane Armand ◽  
Auke Ijspeert
Keyword(s):  
Force Feedback ◽  
Central Pattern Generators ◽  
Step Length ◽  
The Other ◽  
Human Gait ◽  
Dimensional Parameter ◽  
Fast Walking ◽  
Gait Characteristics ◽  
Other Hand ◽  
Step Duration

The central nervous system of humans and other animals modulates spinal cord activity to achieve several locomotion behaviors. Previous neuromechanical models investigated the modulation of human gait changing selected parameters belonging to CPGs (Central Pattern Generators) feedforward oscillatory structures or to feedback reflex circuits. CPG-based models could replicate slow and fast walking by changing only the oscillation’s properties. On the other hand, reflex-based models could achieve different behaviors through optimizations of large dimensional parameter spaces. However, they could not effectively identify individual key reflex parameters responsible for gait characteristics’ modulation. This study investigates which reflex parameters modulate the gait characteristics through neuromechanical simulations. A recently developed reflex-based model is used to perform optimizations with different target behaviors on speed, step length, and step duration to analyze the correlation between reflex parameters and their influence on these gait characteristics. We identified nine key parameters that may affect the target speed ranging from slow to fast walking (0.48 and 1.71 m/s) as well as a large range of step lengths (0.43 and 0.88 m) and step duration (0.51, 0.98 s). The findings show that specific reflexes during stance significantly affect step length regulation, mainly given by positive force feedback of the ankle plantarflexors’ group. On the other hand, stretch reflexes active during swing of iliopsoas and gluteus maximus regulate all the gait characteristics under analysis. Additionally, the results show that the hamstrings’ group’s stretch reflex during the landing phase is responsible for modulating the step length and step duration. Additional validation studies in simulations demonstrated that the modulation of identified reflexes is sufficient to regulate the investigated gait characteristics. Thus, this study provides an overview of possible reflexes involved in modulating speed, step length, and step duration of human gaits.

scholarly journals Sensory modulation of gait characteristics in human locomotion: a neuromusculoskeletal modeling study

2020 ◽  
Author(s):  
Andrea Di Russo ◽  
Dimitar Stanev ◽  
Stéphane Armand ◽  
Auke Ijspeert
Keyword(s):  
Central Pattern Generators ◽  
Step Length ◽  
Human Locomotion ◽  
The Other ◽  
Human Gait ◽  
Dimensional Parameter ◽  
Fast Walking ◽  
Gait Characteristics ◽  
Other Hand ◽  
Step Duration

AbstractThe central nervous system of humans and animals is able to modulate the activity in the spinal cord to achieve several locomotion behaviors. Previous neuromechanical models investigated the modulation of human gait changing selected parameters belonging to the CPGs (Central Pattern Generators) feedforward oscillatory structures or to the feedback reflex circuits. CPG-based models could replicate slow and fast walking by changing only the oscillation’s properties. On the other hand, reflex-based models could achieve different behaviors mainly through optimizations of a large dimensional parameter space, but could not identify effectively individual key reflex parameters responsible for the modulation of gait characteristics. This study, investigates which reflex parameters modulate the gait characteristics through neuromechanical simulations. A recently developed reflex-based model is used to perform optimizations with different target behaviors on speed, step length and step duration in order to analyse the correlation between reflex parameters and their influence on these gait characteristics. We identified 9 key parameters that influence the target speed ranging from slow to fast walking (0.48 and 1.71 m/s) as well as a large range of step lengths (0.43 and 0.88 m) and step duration (0.51, 0.98 s). The findings show that specific reflexes during stance have a major effect on step length regulation mainly given by the contribution of positive force feedback on the ankle plantarflexors’ group. On the other hand, stretch reflexes active during swing of iliopsoas and gluteus maximus regulate all the gait characteristics under analysis. Additionally, the results show that the stretch reflex of the hamstring’s group during landing phase is responsible for modulating the step length and step duration. Additional validation studies in simulations demonstrated that the identified reflexes are sufficient to modulate gait in human locomotion. Thus, this study provides an overview of the possible reflexes to control the gait characteristics.Author summary

Development of Haptic-Enabled Virtual Reality Applications for Engineering, Medicine and Art

2015 ◽  
Author(s):  
Hugo I. Medellín-Castillo ◽  
Germánico González-Badillo ◽  
Eder Govea ◽  
Raquel Espinosa-Castañeda ◽  
Enrique Gallegos
Keyword(s):  
Virtual Reality ◽  
Virtual Environment ◽  
Force Feedback ◽  
Research Work ◽  
Three Dimensional ◽  
Haptic Device ◽  
The Other ◽  
Virtual Objects ◽  
Other Hand ◽  
And Training

The technological growth in the last years have conducted to the development of virtual reality (VR) systems able to immerse the user into a three-dimensional (3D) virtual environment where the user can interact in real time with virtual objects. This interaction is mainly based on visualizing the virtual environment and objects. However, with the recent beginning of haptic systems, the interaction with the virtual world has been extended to also feel, touch and manipulate virtual objects. Virtual reality has been successfully used in the development of applications in different scientific areas ranging from basic sciences, social science, education and entertainment. On the other hand, the use of haptics has increased in the last decade in domains from sciences and engineering to art and entertainment. Despite many developments, there is still relatively little knowledge about the confluence of software, enabling hardware, visual and haptic representations, to enable the conditions that best provide for an immersive sensory environment to convey information about a particular subject domain. In this paper, the state of the art of the research work regarding virtual reality and haptic technologies carried out by the authors in the last years is presented. The aim is to evidence the potential use of these technologies to develop usable systems for analysis and simulation in different areas of knowledge. The development of three different systems in the areas of engineering, medicine and art is presented. In the area of engineering, a system for the planning, evaluation and training of assembly and manufacturing tasks has been developed. The system, named as HAMS (Haptic Assembly and Manufacturing System), is able to simulate assembly tasks of complex components with force feedback provided by the haptic device. On the other hand, in the area of medicine, a surgical simulator for planning and training orthognathic surgeries has been developed. The system, named as VOSS (Virtual Osteotomy Simulator System), allows the realization of virtual osteotomies with force feedback. Finally, in the area of art, an interactive cinema system for blind people has been developed. The system is able to play a 3D virtual movie for the blind user to listen to and touch by means of the haptic device. The development of these applications and the results obtained from these developments are presented and discussed in this paper.

scholarly journals Technique and Understanding: Paul Ricoeur on Freud and the Analytic Experience

2016 ◽  
Vol 7 (1) ◽  
pp. 87-102
Author(s):  
Eoin Carney
Keyword(s):  
Force Feedback ◽  
Paul Ricoeur ◽  
The Other ◽  
Other Hand ◽  
Paul Ricœur ◽  
Scientific Questions ◽  
Or History

For Ricœur any study of Freud, or of psychoanalysis more generally, needs to take into account the crucial dimension of the analytic experience itself. Psychoanalysis, as a “mixed discourse,” aims to anticipate questions of meaning and explication alongside technical questions of energies, repression, displacement, and so on. The analytic experience is one which is practical and intersubjective, but which is also guided by various techniques or methods. These techniques, I will argue, should be understood as a type of techne, one which is less concerned with hermeneutic questions of meaning than with quasi-scientific questions of force, feedback, struggle, and process. The practice of psychoanalysis, on the other hand, deals with the ways in which these forces or drives become meaningful for a particular subject, and within a singular context or history. This article will aim to draw out both the interrelationship between techniques and practical understanding, and also the productive incommensurability between the two.

Wire-Driven Pneumatic Actuation of a New 6-DOF Haptic Master

2006 ◽  
Author(s):  
Carlo Ferraresi ◽  
Massimiliana Carello ◽  
Francesco Pescarmona ◽  
Roberto Grassi
Keyword(s):  
Virtual Reality ◽  
Degrees Of Freedom ◽  
Force Feedback ◽  
Angular Displacement ◽  
Haptic Device ◽  
The Other ◽  
Six Degrees Of Freedom ◽  
Pneumatic Actuation ◽  
Virtual Device ◽  
Other Hand

The paper presents the results of a work carried out by the Department of Mechanics of Politecnico di Torino, concerning the study and development of a six degrees of freedom force reflecting master structure for teleoperation (haptic device) to be controlled by an operator. The latter imposes the six-dimensional linear and angular displacement of a handle, controlling a remote slave robot or interacting with virtual reality. On the other hand, the operator receives a force feedback related to the environment in which the slave robot or virtual device operates. Since the actuators must be force controlled in order to generate a resultant corresponding to the desired wrench, pneumatic actuation has been chosen because it is particularly suitable to the application and quite economical.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

Can the Academic Self-Concept be Positive and Realistic?

2005 ◽  
Vol 19 (3) ◽  
pp. 129-132 ◽  
Author(s):  
Reimer Kornmann
Keyword(s):  
Academic Performance ◽  
Opposite Effect ◽  
Self Esteem ◽  
Point Of View ◽  
The Other ◽  
Self Concept ◽  
High Ability ◽  
Self Image ◽  
Other Hand

Summary: My comment is basically restricted to the situation in which less-able students find themselves and refers only to literature in German. From this point of view I am basically able to confirm Marsh's results. It must, however, be said that with less-able pupils the opposite effect can be found: Levels of self-esteem in these pupils are raised, at least temporarily, by separate instruction, academic performance however drops; combined instruction, on the other hand, leads to improved academic performance, while levels of self-esteem drop. Apparently, the positive self-image of less-able pupils who receive separate instruction does not bring about the potential enhancement of academic performance one might expect from high-ability pupils receiving separate instruction. To resolve the dilemma, it is proposed that individual progress in learning be accentuated, and that comparisons with others be dispensed with. This fosters a self-image that can in equal measure be realistic and optimistic.

Stories and the Self

2020 ◽  
Vol 32 (2) ◽  
pp. 47-58 ◽  
Author(s):  
Stefan Krause ◽  
Markus Appel
Keyword(s):  
Meta Analysis ◽  
The Self ◽  
The Other ◽  
Lower Degree ◽  
Contrast Effects ◽  
Self Perception ◽  
Self Perceptions ◽  
Other Hand ◽  
The One ◽  
Implicit And Explicit

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.

Don’t Put Me in This Group

2019 ◽  
Vol 50 (2) ◽  
pp. 80-93
Author(s):  
Jort de Vreeze ◽  
Christina Matschke
Keyword(s):  
Positive Emotions ◽  
Negative Emotions ◽  
Negative Information ◽  
The Self ◽  
The Other ◽  
Other Hand ◽  
Group Memberships

Abstract. Not all group memberships are self-chosen. The current research examines whether assignments to non-preferred groups influence our relationship with the group and our preference for information about the ingroup. It was expected and found that, when people are assigned to non-preferred groups, they perceive the group as different to the self, experience negative emotions about the assignment and in turn disidentify with the group. On the other hand, when people are assigned to preferred groups, they perceive the group as similar to the self, experience positive emotions about the assignment and in turn identify with the group. Finally, disidentification increases a preference for negative information about the ingroup.

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