scholarly journals A Critical Review of the Support for Variability as an Operant Dimension

2020 ◽  
Vol 43 (3) ◽  
pp. 579-603 ◽  
Author(s):  
Siv Kristin Nergaard ◽  
Per Holth
Keyword(s):  
Animal Behavior ◽  
Critical Review ◽  
Dynamic Interaction ◽  
High Variability ◽  
Behavioral Variability ◽  
Independent Variables ◽  
Abundant Evidence ◽  
Alternative Hypotheses ◽  
Direct Reinforcement ◽  
Underlying Mechanisms

AbstractThere is abundant evidence that behavioral variability is more predominant when reinforcement is contingent on it than when it is not, and the interpretation of direct reinforcement of variability suggested by Page and Neuringer, Journal of Experimental Psychology: Animal Behavior Processes, 11(3), 429–452 (1985) has been widely accepted. Even so, trying to identify the underlying mechanisms in the emergence of stochastic-like variability in a variability contingency is intricate. There are several challenges to characterizing variability as directly reinforced, most notably because reinforcement traditionally has been found to produce repetitive responding, but also because directly reinforced variability does not always relate to independent variables the same way as more commonly studied repetitive responding does. The challenging findings in variability experiments are discussed, along with alternative hypotheses on how variability contingencies may engender the high variability that they undeniably do. We suggest that the typical increase in behavioral variability that is often demonstrated when reinforcement is contingent on it may be better explained in terms of a dynamic interaction of reinforcement and extinction working on several specific responses rather than as directly reinforced.

Studies of Imitative Learning and Vicarious Reinforcement

1984 ◽  
Vol 55 (1) ◽  
pp. 279-289
Author(s):  
Carol Shaw Austad ◽  
Rollin Sininger ◽  
Jane Daugherty ◽  
Dennis Geary ◽  
Judy Stange
Keyword(s):  
Behavioral Reactions ◽  
Imitative Learning ◽  
Independent Variables ◽  
Target Behaviors ◽  
Actual Use ◽  
Within Subjects ◽  
Series Of Experiments ◽  
Direct Reinforcement ◽  
Vicarious Reinforcement ◽  
Concrete Operations

This article examined theoretical and practical aspects of vicarious reinforcement. Vicarious reinforcement is described as a metaphor, created by drawing attention to the similarities between vicarious and direct reinforcement. If vicarious reinforcement is analogous to direct reinforcement, it is possible to treat them in the same way. A series of experiments with 60 children were conducted to translate the metaphor into concrete operations. The dependent variable was percentage of time spent in imitative play. The independent variables were the systematic application of vicarious punishment, vicarious reinforcement, and neutral consequences. The prediction that vicarious reinforcement increases target behaviors and vicarious punishment decreases target behaviors did not hold. Analysis showed variation between and within subjects in behavioral reactions to vicarious reinforcement and punishment. In actual use, there are methodological complexities in application of vicarious events.

scholarly journals Robust Optimization of Alginate-Carbopol 940 Bead Formulations

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
J. M. López-Cacho ◽  
Pedro L. González-R ◽  
B. Talero ◽  
A. M. Rabasco ◽  
M. L. González-Rodríguez
Keyword(s):  
Robust Optimization ◽  
Signal To Noise Ratio ◽  
High Variability ◽  
Point Of View ◽  
Orthogonal Array Design ◽  
Complex Activity ◽  
Drug Release Profile ◽  
Independent Variables ◽  
Taguchi Orthogonal Array ◽  
Carbopol 940

Formulation process is a very complex activity which sometimes implicates taking decisions about parameters or variables to obtain the best results in a high variability or uncertainty context. Therefore, robust optimization tools can be very useful for obtaining high quality formulations. This paper proposes the optimization of different responses through the robust Taguchi method. Each response was evaluated like a noise variable, allowing the application of Taguchi techniques to obtain a response under the point of view of the signal to noise ratio. AL18Taguchi orthogonal array design was employed to investigate the effect of eight independent variables involved in the formulation of alginate-Carbopol beads. Responses evaluated were related to drug release profile from beads (t50%and AUC), swelling performance, encapsulation efficiency, shape and size parameters. Confirmation tests to verify the prediction model were carried out and the obtained results were very similar to those predicted in every profile. Results reveal that the robust optimization is a very useful approach that allows greater precision and accuracy to the desired value.

Experimental Harvesting of Cyclic Stocks in the Face of Alternative Recruitment Hypotheses

1990 ◽  
Vol 47 (3) ◽  
pp. 595-610 ◽  
Author(s):  
Ana M. Parma ◽  
Richard B. Deriso
Keyword(s):  
Optimal Harvesting ◽  
Environmental Forcing ◽  
Extreme Risk ◽  
Fully Adaptive ◽  
The Face ◽  
Alternative Hypotheses ◽  
Underlying Mechanisms ◽  
Adaptive Policies ◽  
Active Controls ◽  
Recruitment Model

Cyclic fluctuations in year-class abundance have been recorded for several fish populations. Historical patterns are generally consistent with several hypotheses about underlying mechanisms, which involve (a) strong density dependence or (b) environmental forcing. Optimal harvesting policies differ depending on which hypothesis is deemed true. Not only does the harvesting policy affect the amount of catch taken, but it can strongly affect our ability to discriminate between alternative hypotheses. Fully-adaptive feedback policies, which explicitly account for the information content of harvest controls, were computed with dynamic progamming for some model prototypes of the problem. Results indicate that deliberate experimentation with escapement levels, oriented to reduce the uncertainty, may be worthwhile under some conditions. In most cases, however, optimal passive policies (in which learning occurs passively) were a good approximation to actively adaptive policies. The optimal passive controls for maximizing a risk-neutral objective, such as total catch, were generally very informative. Although passive and active controls markedly differed in some cases, expected discounted yields under the two types of policies were very similar (differences less than 2%). The extreme risk-averse presciption of managing a stock according to the more pessimistic recruitment model may lead to considerable yield losses.

Measuring tourism success – alternative outcome variables: a perspective article

2019 ◽  
Vol 75 (1) ◽  
pp. 182-186
Author(s):  
Muzaffer Uysal
Keyword(s):  
Critical Review ◽  
Design Methodology ◽  
Well Being ◽  
Content Type ◽  
Observational Analysis ◽  
Independent Variables ◽  
Alternative Outcome ◽  
New Directions ◽  
Dependent Variables ◽  
The Future

Purpose The focus of this perspective paper is to provide new directions in the ontology of thinking about outcome variables by observational analysis of past and linking it to the present research. Design/methodology/approach This perspective paper follow a critical review approach that is reflective and speculative in its orientation. Findings Outcome variables are assumed to serve as the dependent variables which are observed and measured by changing independent variables. It is argued that there would certainly be more and innovative concerted efforts in the future that would focus on non-conventional measures as outcome variables. These efforts would help researchers better understand the contribution of tourism activities to well-being of stakeholders. By doing so, success in tourism can be ensured. Originality/value Proposing, in addition to conventional outcome variables, new/possible outcome variables to enrich research.

scholarly journals Characterising low-cost sensors in highly portable platforms to quantify personal exposure in diverse environments

2019 ◽  
Author(s):  
Lia Chatzidiakou ◽  
Anika Krause ◽  
Olalekan A. M. Popoola ◽  
Andrea Di Antonio ◽  
Mike Kellaway ◽  
...  
Keyword(s):  
Air Pollution ◽  
Large Scale ◽  
Daily Life ◽  
Low Cost ◽  
Personal Exposure ◽  
High Variability ◽  
Health Studies ◽  
Underlying Mechanisms ◽  
Exposure Metrics ◽  
Standard Instrumentation

Abstract. The inaccurate quantification of personal exposure to air pollution introduces error and bias in health estimations, severely limiting causal inference in epidemiological research worldwide. Rapid advancements in affordable, miniaturised air pollution sensor technologies offer the potential to address this limitation by capturing the high variability of personal exposure during daily life in large-scale studies with unprecedented spatial and temporal resolution. However, concerns remain regarding the suitability of novel sensing technologies for scientific and policy purposes. In this paper we characterise the performance of a portable personal air quality monitor (PAM) that integrates multiple miniaturised sensors for nitrogen oxides (NOx), carbon monoxide (CO), ozone (O3) and particulate matter (PM) measurements along with temperature, relative humidity, acceleration, noise and GPS sensors. Overall, the air pollution sensors showed excellent agreement with standard instrumentation in outdoor, indoor and commuting microenvironments across seasons and different geographical settings. An important outcome of this study is that the error of the PAM is significantly smaller than the error introduced when estimating personal exposure based on sparsely distributed outdoor fixed monitoring stations. Hence, novel sensing technologies as the ones demonstrated here can revolutionise health studies by providing highly resolved reliable exposure metrics at large scale to investigate the underlying mechanisms of the effects of air pollution on health.

Salience of multisensory feedback regulates behavioral variability

2021 ◽  
Author(s):  
Muhammed Seyda Comertler ◽  
Ismail Uyanik
Keyword(s):  
Robust Control ◽  
Animal Behavior ◽  
Sensory Feedback ◽  
Electric Fish ◽  
Control Strategies ◽  
Weakly Electric Fish ◽  
Behavioral Variability ◽  
Neural Controllers ◽  
Eigenmannia Virescens ◽  
Weakly Electric

Abstract Many animal behaviors are robust to dramatic variations in morphophysiological features, both across and within individuals. The control strategies that animals use to achieve such robust behavioral performances are not known. Recent evidence suggests that animals rely on sensory feedback rather than precise tuning of neural controllers for robust control. Here we examine the structure of sensory feedback, including multisensory feedback, for robust control of animal behavior. We re-examined two recent datasets of refuge tracking responses of Eigenmannia virescens, a species of weakly electric fish. Eigenmannia rely on both the visual and electrosensory cues to track the position of a moving refuge. The datasets include experiments that varied the strength of visual and electrosensory signals. Our analyses show that increasing the salience (perceptibility) of visual or electrosensory signals resulted in more robust and precise behavioral responses. Further, we find that robust performance was enhanced by multisensory integration of simultaneous visual and electrosensory cues. These findings suggest that engineers may achieve better system performance by improving the salience of multisensory feedback rather than solely focusing on precisely tuned controllers.

scholarly journals Characterising low-cost sensors in highly portable platforms to quantify personal exposure in diverse environments

2019 ◽  
Vol 12 (8) ◽  
pp. 4643-4657 ◽  
Author(s):  
Lia Chatzidiakou ◽  
Anika Krause ◽  
Olalekan A. M. Popoola ◽  
Andrea Di Antonio ◽  
Mike Kellaway ◽  
...  
Keyword(s):  
Air Pollution ◽  
Large Scale ◽  
Low Cost ◽  
Personal Exposure ◽  
High Variability ◽  
High Reproducibility ◽  
Health Studies ◽  
Underlying Mechanisms ◽  
Exposure Metrics ◽  
Standard Instrumentation

Abstract. The inaccurate quantification of personal exposure to air pollution introduces error and bias in health estimations, severely limiting causal inference in epidemiological research worldwide. Rapid advancements in affordable, miniaturised air pollution sensor technologies offer the potential to address this limitation by capturing the high variability of personal exposure during daily life in large-scale studies with unprecedented spatial and temporal resolution. However, concerns remain regarding the suitability of novel sensing technologies for scientific and policy purposes. In this paper we characterise the performance of a portable personal air quality monitor (PAM) that integrates multiple miniaturised sensors for nitrogen oxides (NOx), carbon monoxide (CO), ozone (O3) and particulate matter (PM) measurements along with temperature, relative humidity, acceleration, noise and GPS sensors. Overall, the air pollution sensors showed high reproducibility (mean R‾2=0.93, min–max: 0.80–1.00) and excellent agreement with standard instrumentation (mean R‾2=0.82, min–max: 0.54–0.99) in outdoor, indoor and commuting microenvironments across seasons and different geographical settings. An important outcome of this study is that the error of the PAM is significantly smaller than the error introduced when estimating personal exposure based on sparsely distributed outdoor fixed monitoring stations. Hence, novel sensing technologies such as the ones demonstrated here can revolutionise health studies by providing highly resolved reliable exposure metrics at a large scale to investigate the underlying mechanisms of the effects of air pollution on health.

Comparative Study on Intergranular Segregation of Sulfur and Phosphorus Induced During Neutron Irradiation And Thermal Ageing in Vanadium-20 WT.% Titanium Alloys

1996 ◽  
Vol 439 ◽  
Author(s):  
T. E. Bloomer ◽  
D. Y. Lyu ◽  
J. Kameda
Keyword(s):  
Grain Boundary ◽  
Comparative Study ◽  
Titanium Alloys ◽  
Neutron Irradiation ◽  
Dynamic Interaction ◽  
Thermal Ageing ◽  
Vanadium Alloys ◽  
Impurity Segregation ◽  
Ti Alloys ◽  
Underlying Mechanisms

AbstractIntergranular impurity segregation induced during neutron irradiation (9.8 × 1024 n/mr at 438 °C) and thermal ageing has been studied in V-20 wt.% Ti alloys undoped, P doped and S doped all containing residual C and O. Neutron irradiation induced intergranular segregation and desegregation of S in undoped and S doped alloys, respectively. Thermal ageing resulted in a large increase in the S segregation in the undoped and S doped alloys. However, all unirradiated, aged and irradiated P doped alloys showed negligible S segregation. The vanadium alloys had smaller P segregation, compared to the S segregation in the undoped and S doped alloys. The irradiation and ageing enhanced the P segregation in a different fashion depending on the alloys. The grain boundary enrichment of C, O and Ti was reduced during the irradiation but promoted by the thermal ageing. The underlying mechanisms controlling intergranular impurity segregation caused by irradiation or thermal ageing are discussed in light of the impurity solubility change and dynamic interaction of defect and impurity fluxes.

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