270 research outputs found
When can the two-armed bandit algorithm be trusted?
We investigate the asymptotic behavior of one version of the so-called
two-armed bandit algorithm. It is an example of stochastic approximation
procedure whose associated ODE has both a repulsive and an attractive
equilibrium, at which the procedure is noiseless. We show that if the gain
parameter is constant or goes to 0 not too fast, the algorithm does fall in the
noiseless repulsive equilibrium with positive probability, whereas it always
converges to its natural attractive target when the gain parameter goes to zero
at some appropriate rates depending on the parameters of the model. We also
elucidate the behavior of the constant step algorithm when the step goes to 0.
Finally, we highlight the connection between the algorithm and the
Polya urn. An application to asset allocation is briefly described
How fast is the bandit?
International audienceIn this paper we investigate the rate of convergence of the so-called two-armed bandit algorithm in a financial context of asset allocation. The behaviour of the algorithm turns out to be highly non-standard: no CLT whatever the time scale, possible existence of two rate regimes
Learning to deal with COTS (commercial off the shelf)
With the advent of model based development technologies, dependence of COTS in software development has increased considerably. Use of COTS is considered economical and practical when it comes to integration of various software components. However COTS are trapped with some pitfalls. COTS provided are not usually accompanied by models or extensive specifications. This approach makes usage & integration of COTS components with in house developed software components a very challenging task. Conformance of the implementation with the specification forms the basis for our approach. In this thesis, we analyze an approach where the model is extracted from the COTS software that greatly aids in integration.;We developed a system that extracts the state machine model from the COTS software using Dana Angluin\u27s L* Algorithm. We also developed a hierarchical approach of viewing the state machine model by static analysis of assembly code
Regret bounds for Narendra-Shapiro bandit algorithms
Narendra-Shapiro (NS) algorithms are bandit-type algorithms that have been
introduced in the sixties (with a view to applications in Psychology or
learning automata), whose convergence has been intensively studied in the
stochastic algorithm literature. In this paper, we adress the following
question: are the Narendra-Shapiro (NS) bandit algorithms competitive from a
\textit{regret} point of view? In our main result, we show that some
competitive bounds can be obtained for such algorithms in their penalized
version (introduced in \cite{Lamberton_Pages}). More precisely, up to an
over-penalization modification, the pseudo-regret related to the
penalized two-armed bandit algorithm is uniformly bounded by
(where is made explicit in the paper). \noindent We also generalize
existing convergence and rates of convergence results to the multi-armed case
of the over-penalized bandit algorithm, including the convergence toward the
invariant measure of a Piecewise Deterministic Markov Process (PDMP) after a
suitable renormalization. Finally, ergodic properties of this PDMP are given in
the multi-armed case
Memory requirements for the detection of impostor nodes in wireless sensor networks
This paper shows how it is at least in principle possible to detect impostor nodes in
wireless sensor networks with a quite simplistic detection algorithm by purely statistical
means and merely from external observation without any knowledge of the impostorâs internal
composition. This method, however, requires considerable volumes of internal memory
for any WSN node on which such detection algorithms are supposed to be implemented.http://www.easychair.org/publications/EPiC/Computingam2023Computer Scienc
Information Processing, Computation and Cognition
Computation and information processing are among the most fundamental notions in cognitive science. They are also among the most imprecisely discussed. Many cognitive scientists take it for granted that cognition involves computation, information processing, or both â although others disagree vehemently. Yet different cognitive scientists use âcomputationâ and âinformation processingâ to mean different things, sometimes without realizing that they do. In addition, computation and information processing are surrounded by several myths; first and foremost, that they are the same thing. In this paper, we address this unsatisfactory state of affairs by presenting a general and theory-neutral account of computation and information processing. We also apply our framework by analyzing the relations between computation and information processing on one hand and classicism and connectionism/computational neuroscience on the other. We defend the relevance to cognitive science of both computation, at least in a generic sense, and information processing, in three important senses of the term. Our account advances several foundational debates in cognitive science by untangling some of their conceptual knots in a theory-neutral way. By leveling the playing field, we pave the way for the future resolution of the debatesâ empirical aspects
Synthesis of Event-Based Controllers for Software Engineering
Behavioural modelling has been widely used to aid in the design of concurrent
systems. Behaviour models have shown to be useful to uncover design
errors in early stages of the development process. However, building correct
behaviour models is costly and requires significant experience. Controller
synthesis offers a way to build models that are correct by construction. Existing
software engineering techniques for synthesising controllers have various
limitations. Such limitations can be seen as restrictions in the expressiveness
of the controller goals and environment model, or in the relation between
the controllable and monitored actions. The main aim of this thesis is the
development of novel techniques overcoming known limitations of previous
approaches and methodological guidelines for synthesising useful controllers.
This thesis establishes the framework for controller synthesis techniques that
support event-based models, expressive goal specifications, distinguish controllable
from monitored actions and guarantee achievement of the desired
goals. Together with these techniques, methodological guidelines are proposed
to help in building more accurate descriptions of the environment and
more effective controllers.
In addition, this thesis presents a tool that implements the proposed techniques.
Evaluation of the techniques has been conducted using the tool
to model known case studies from the literature, showing that by allowing
more expressive controller goals and environment models, and explicitly distinguishing
controllable and monitored actions such case studies can be more
accurately modelled and solutions guaranteeing satisfaction of the goals can
be achieved
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