4,202 research outputs found
From Cognition to Consciousness:\ud a discussion about learning, reality representation and decision making.
The scientific understanding of cognition and consciousness is currently hampered by the lack of rigorous and universally accepted definitions that permit comparative studies. This paper proposes new functional and un- ambiguous definitions for cognition and consciousness in order to provide clearly defined boundaries within which general theories of cognition and consciousness may be developed. The proposed definitions are built upon the construction and manipulation of reality representation, decision making and learning and are scoped in terms of an underlying logical structure. It is argued that the presentation of reality also necessitates the concept of ab- sence and the capacity to perform transitive inference. Explicit predictions relating to these new definitions, along with possible ways to test them, are also described and discussed
Dissimilarity Clustering by Hierarchical Multi-Level Refinement
We introduce in this paper a new way of optimizing the natural extension of
the quantization error using in k-means clustering to dissimilarity data. The
proposed method is based on hierarchical clustering analysis combined with
multi-level heuristic refinement. The method is computationally efficient and
achieves better quantization errors than theComment: 20-th European Symposium on Artificial Neural Networks, Computational
Intelligence and Machine Learning (ESANN 2012), Bruges : Belgium (2012
Better Optimism By Bayes: Adaptive Planning with Rich Models
The computational costs of inference and planning have confined Bayesian
model-based reinforcement learning to one of two dismal fates: powerful
Bayes-adaptive planning but only for simplistic models, or powerful, Bayesian
non-parametric models but using simple, myopic planning strategies such as
Thompson sampling. We ask whether it is feasible and truly beneficial to
combine rich probabilistic models with a closer approximation to fully Bayesian
planning. First, we use a collection of counterexamples to show formal problems
with the over-optimism inherent in Thompson sampling. Then we leverage
state-of-the-art techniques in efficient Bayes-adaptive planning and
non-parametric Bayesian methods to perform qualitatively better than both
existing conventional algorithms and Thompson sampling on two contextual
bandit-like problems.Comment: 11 pages, 11 figure
Efficient Bayes-Adaptive Reinforcement Learning using Sample-Based Search
Bayesian model-based reinforcement learning is a formally elegant approach to
learning optimal behaviour under model uncertainty, trading off exploration and
exploitation in an ideal way. Unfortunately, finding the resulting
Bayes-optimal policies is notoriously taxing, since the search space becomes
enormous. In this paper we introduce a tractable, sample-based method for
approximate Bayes-optimal planning which exploits Monte-Carlo tree search. Our
approach outperformed prior Bayesian model-based RL algorithms by a significant
margin on several well-known benchmark problems -- because it avoids expensive
applications of Bayes rule within the search tree by lazily sampling models
from the current beliefs. We illustrate the advantages of our approach by
showing it working in an infinite state space domain which is qualitatively out
of reach of almost all previous work in Bayesian exploration.Comment: 14 pages, 7 figures, includes supplementary material. Advances in
Neural Information Processing Systems (NIPS) 201
Warm molecular gas, dust and ionized gas in the 500 central pc of the Galaxy
We present infrared and millimeter observations of molecular gas, dust and
ionized gas towards a sample of clouds distributed along the 500 central pc of
the Galaxy. The clouds were selected to investigate the physical state, in
particular the high gas temperatures, of the Galactic center region (GCr)
clouds located far from far-infrared of thermal radio continuum sources. We
have found that there is ionized gas associated with the molecular gas. The
ionizing radiation is hard (~35000 K) but diluted due to the inhomogeneity of
the medium. We estimate that ~30 % of the warm molecular gas observed in the
GCr clouds is heated by ultra-violet radiation in photo-dissociation regions.Comment: 5 pages, to be published in: Astron. Nachr., Vol. 324, No. S1 (2003),
Special Supplement "The central 300 parsecs of the Milky Way", Eds. A.
Cotera, H. Falcke, T. R. Geballe, S. Markof
Deep Reinforcement Learning with Double Q-learning
The popular Q-learning algorithm is known to overestimate action values under
certain conditions. It was not previously known whether, in practice, such
overestimations are common, whether they harm performance, and whether they can
generally be prevented. In this paper, we answer all these questions
affirmatively. In particular, we first show that the recent DQN algorithm,
which combines Q-learning with a deep neural network, suffers from substantial
overestimations in some games in the Atari 2600 domain. We then show that the
idea behind the Double Q-learning algorithm, which was introduced in a tabular
setting, can be generalized to work with large-scale function approximation. We
propose a specific adaptation to the DQN algorithm and show that the resulting
algorithm not only reduces the observed overestimations, as hypothesized, but
that this also leads to much better performance on several games.Comment: AAAI 201
Archaeology and dental forensic: what’s the relationship?
Archaeology is a science combining numerous skills in a multidisciplinary approach. In the
presence of human remains, its objectives are the recovery, identification, and analysis on an
anthropological purpose to reconstruct the context of the individual's past lives. One of these
approaches is in the forensic medicine sciences whose main purpose is the identification of human
bodies through bones and teeth in deteriorated corpses. Archaeology and forensic medicine are
therefore two intertwined sciences.
The goal of this bibliographical review is to summarize the first steps to reconstruct the
biological profile of a person using teeth as an object of study. Beginning by explaining the
preservation and the type of the tooth sample, then by assessing the two most important biological
factors being the sex and the age. This study does not cover all the existing tooth forensic aspects,
but the most used one and the promising methods for archaeological context.A arqueologia é uma ciência que combina uma abordagem multidisciplinar. Na presença de
restos cadavéricos, os seus principais objetivos são a recuperação, identificação e análise com o
propósito antropológico de reconstruir o contexto das vidas passadas do indivÃduo. Uma dessas
abordagens relaciona-se com a medicina forense, cujo objetivo principal é a identificação humana
através da ossada e dos dentes em cadáveres deteriorados. A arqueologia e a medicina forense são,
portanto, duas ciências interligadas.
O objetivo desta revisão bibliográfica é resumir os primeiros passos para a reconstrução do
perfil biológico de uma pessoa, utilizando as peças dentárias como objeto de estudo, começando por
explicar a preservação e o tipo da amostra dentária e avaliando dois fatores biológicos, tais como o
sexo e a idade. Este estudo não abrange todos os aspetos forenses dentários existentes, mas os
métodos mais utilizados e os métodos mais promissores para o contexto arqueológico
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