A computational model for distributed knowledge systems with learning mechanisms

1996 ◽  
Vol 10 (3-4) ◽  
pp. 417-427 ◽  
Author(s):  
H Aibat
Author(s):  
О. Z. Mintser ◽  
О. Ye. Stryzhak ◽  
S. V. Denysenko

<p class="a0">Approaches, facilities and technologies of forming of the personalized electronic grounds of management in the educational- informative environment knowledge are described. The ontological aspects of model scenario construction in doctor’s education post-graduate training accompaniment are considered with the use of the network systems of knowledge. It supposes the decision of increasing of efficiency medical educating of doctors on application of modern network technologies of the distance access to t h e distributed knowledge systems.</p>


2020 ◽  
Author(s):  
José R. Donoso ◽  
Julian Packheiser ◽  
Roland Pusch ◽  
Zhiyin Lederer ◽  
Thomas Walther ◽  
...  

AbstractExtinction learning, the process of ceasing an acquired behavior in response to altered reinforcement contingencies, is essential for survival in a changing environment. So far, research has mostly neglected the learning dynamics and variability of behavior during extinction learning and instead focused on a few response types that were studied by population averages. Here, we take a different approach by analyzing the trial-by-trial dynamics of operant extinction learning in both pigeons and a computational model. The task involved discriminant operant conditioning in context A, extinction in context B, and a return to context A to test the context-dependent return of the conditioned response (ABA renewal). By studying single learning curves across animals under repeated sessions of this paradigm, we uncovered a rich variability of behavior during extinction learning: (1) Pigeons prefer the unrewarded alternative choice in one-third of the sessions, predominantly during the very first extinction session an animal encountered. (2) In later sessions, abrupt transitions of behavior at the onset of context B emerge, and (3) the renewal effect decays as sessions progress. While these results could be interpreted in terms of rule learning mechanisms, we show that they can be parsimoniously accounted for by a computational model based only on associative learning between stimuli and actions. Our work thus demonstrates the critical importance of studying the trial-by-trial dynamics of learning in individual sessions, and the unexpected power of “simple” associative learning processes.Significance StatementOperant conditioning is essential for the discovery of purposeful actions, but once a stimulus-response association is acquired, the ability to extinguish it in response to altered reward contingencies is equally important. These processes also play a fundamental role in the development and treatment of pathological behaviors such as drug addiction, overeating and gambling. Here we show that extinction learning is not limited to the cessation of a previously reinforced response, but also drives the emergence of complex and variable choices that change from learning session to learning session. At first sight, these behavioral changes appear to reflect abstract rule learning, but we show in a computational model that they can emerge from “simple” associative learning.


2006 ◽  
Vol 18 (2) ◽  
pp. 283-328 ◽  
Author(s):  
Randall C. O'Reilly ◽  
Michael J. Frank

The prefrontal cortex has long been thought to subserve both working memory (the holding of information online for processing) and executive functions (deciding how to manipulate working memory and perform processing). Although many computational models of working memory have been developed, the mechanistic basis of executive function remains elusive, often amounting to a homunculus. This article presents an attempt to deconstruct this homunculus through powerful learning mechanisms that allow a computational model of the prefrontal cortex to control both itself and other brain areas in a strategic, task-appropriate manner. These learning mechanisms are based on subcortical structures in the midbrain, basal ganglia, and amygdala, which together form an actor-critic architecture. The critic system learns which prefrontal representations are task relevant and trains the actor, which in turn provides a dynamic gating mechanism for controlling working memory updating. Computationally, the learning mechanism is designed to simultaneously solve the temporal and structural credit assignment problems. The model's performance compares favorably with standard backpropagation-based temporal learning mechanisms on the challenging 1-2-AX working memory task and other benchmark working memory tasks.


2019 ◽  
Vol 56 (4) ◽  
pp. 29-36
Author(s):  
Ilya T. Kasavin ◽  

The epitome of modern scientific infrastructure and distributed knowledge systems is scientific social networks (NSS). Their number, as well as the number of their users, is constantly growing and reaches millions. They are in demand, and, therefore, perform significant social functions. It is still unclear what their own nature is, what their functions are and how they perform and, finally, what are the consequences of their integration with the social institute of science. Along with the obvious advantages, the NSS creates clear cultural dissonances and challenges that change the usual ways of communication. There is already enough evidence that the NSS not only bring about positive change, but also face rejection. Science policy, the scientist's moral code, the scientific citation and evaluation systems are all affected by the activities of the NSS and become an important subject matter of science and technology studies (STS). This text is a response to the article “Social Networks for Researchers on the Internet: A New Sociality?” by S.V. Shibarshina.


2009 ◽  
Vol 17 (6) ◽  
pp. 467-483 ◽  
Author(s):  
Manuel Lopes ◽  
Francisco S. Melo ◽  
Ben Kenward ◽  
José Santos-Victor

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