16 research outputs found
Learning, Generalization, and Functional Entropy in Random Automata Networks
It has been shown \citep{broeck90:physicalreview,patarnello87:europhys} that
feedforward Boolean networks can learn to perform specific simple tasks and
generalize well if only a subset of the learning examples is provided for
learning. Here, we extend this body of work and show experimentally that random
Boolean networks (RBNs), where both the interconnections and the Boolean
transfer functions are chosen at random initially, can be evolved by using a
state-topology evolution to solve simple tasks. We measure the learning and
generalization performance, investigate the influence of the average node
connectivity , the system size , and introduce a new measure that allows
to better describe the network's learning and generalization behavior. We show
that the connectivity of the maximum entropy networks scales as a power-law of
the system size . Our results show that networks with higher average
connectivity (supercritical) achieve higher memorization and partial
generalization. However, near critical connectivity, the networks show a higher
perfect generalization on the even-odd task
Replica theory for learning curves for Gaussian processes on random graphs
Statistical physics approaches can be used to derive accurate predictions for
the performance of inference methods learning from potentially noisy data, as
quantified by the learning curve defined as the average error versus number of
training examples. We analyse a challenging problem in the area of
non-parametric inference where an effectively infinite number of parameters has
to be learned, specifically Gaussian process regression. When the inputs are
vertices on a random graph and the outputs noisy function values, we show that
replica techniques can be used to obtain exact performance predictions in the
limit of large graphs. The covariance of the Gaussian process prior is defined
by a random walk kernel, the discrete analogue of squared exponential kernels
on continuous spaces. Conventionally this kernel is normalised only globally,
so that the prior variance can differ between vertices; as a more principled
alternative we consider local normalisation, where the prior variance is
uniform
Self Normalizing Flows
Efficient gradient computation of the Jacobian determinant term is a core
problem in many machine learning settings, and especially so in the normalizing
flow framework. Most proposed flow models therefore either restrict to a
function class with easy evaluation of the Jacobian determinant, or an
efficient estimator thereof. However, these restrictions limit the performance
of such density models, frequently requiring significant depth to reach desired
performance levels. In this work, we propose Self Normalizing Flows, a flexible
framework for training normalizing flows by replacing expensive terms in the
gradient by learned approximate inverses at each layer. This reduces the
computational complexity of each layer's exact update from
to , allowing for the training of flow architectures which
were otherwise computationally infeasible, while also providing efficient
sampling. We show experimentally that such models are remarkably stable and
optimize to similar data likelihood values as their exact gradient
counterparts, while training more quickly and surpassing the performance of
functionally constrained counterparts
Estimation of soluble solids content and fruit temperature in 'rocha' pear using Vis-NIR spectroscopy and the spectraNetâ32 deep learning architecture
Spectra-based methods are becoming increasingly important in Precision Agriculture as they offer non-destructive, quick tools for measuring the quality of produce. This study introduces a novel approach for esti-mating the soluble solids content (SSC) of 'Rocha' pears using the SpectraNet-32 deep learning architecture, which operates on 1D fruit spectra in the visible to near-infrared region (Vis-NIRS). This method was also able to estimate fruit temperatures, which improved the SSC prediction performance. The dataset consisted of 3300 spectra from 1650 'Rocha' pears collected from local markets over several weeks during the 2010 and 2011 seasons, which had varying edaphoclimatic conditions. Two types of partial least squares (PLS) feature selection methods, under various configurations, were applied to the input spectra to identify the most significant wavelengths for training SpectraNet-32. The model's robustness was also compared to a similar state-of-the-art deep learning architecture, DeepSpectra, as well as four other classical machine learning algorithms: PLS, multiple linear regression (MLR), support vector machine (SVM), and multi-layer perceptron (MLP). In total, 23 different experimental method configurations were assessed, with 150 neural networks each. SpectraNet-32 consistently outperformed other methods in several metrics. On average, it was 6.1% better than PLS in terms of the root mean square error of prediction (RMSEP, 1.08 vs. 1.15%), 7.7% better in prediction gain (PG, 1.67 vs. 1.55), 3.6% better in the coefficient of determination (R2, 0.58 vs. 0.56) and 5.8% better in the coefficient of variation (CV%, 8.35 vs. 8.86).info:eu-repo/semantics/publishedVersio
Nonholonomic Mobile Robot Trajectory Tracking using Hybrid Controller
ABSTRACT A control scheme is being presented for the trajectory tracking of a nonholonomic kinematic model of mobile robots. As a kinematic model of mobile robots is nonlinear in nature, therefore, it is controlling is always being a difficult task. Thus, a control hybrid scheme comprises of fuzzy logic and PID (Proportional Integral Derivative) is being proposed, in which adaptive gains of PID controller is being tuned by a fuzzy logic controller. Moreover, the effectiveness of this innovative technique is also proved using the simulations by adding model uncertainties and external disturbances in the system. Besides, the fuzzy logic control system is also being compared by the proposed control system. Resultsattained shows that the fuzzy based PID controller drivesimproved results than fuzzy logic controller
MODELO NEURO-FUZZY DE APOIO Ă DECISĂO BASEADO NOS CLIENTES EM SHOPPING CENTER
Este estudo apresenta o desenvolvimento de um modelo matemĂĄtico de apoio Ă decisĂŁo, baseado em atributos relevantes Ă percepção dos clientes de um Shopping Center. Abordam-se os aspectos relacionados Ă qualidade do shopping quanto ao bem-estar, lazer e consumo. Com foco exploratĂłrio, em uma pesquisa de natureza aplicada, apoiou-se na revisĂŁo bibliogrĂĄfica para identificação dos atributos vinculados com a experiĂȘncia do cliente em Shopping Center, seguindo-se com abordagem qualitativa aplicada em estudo de caso. Para tal necessitou-se entrevistar 100 pessoas para coleta de dados sobre os atributos. A saĂda do modelo permite refletir o consenso da opiniĂŁo dos clientes por intermĂ©dio de indicadores gerenciais. Sendo o principal o IPC, que resultou em 6,90 para [0,10], sendo zero a pior nota. Embora oresultado do IPC evidencie nĂŁo superação Ă s expectativas dos clientes, osserviços outros indicadores, em sua maioria, caracterizam melhoria, mas com margem de aperfeiçoamento
Simulation d'un réseau de neurones à l'aide de transistors SET
Ce mĂ©moire est le rĂ©sultat d'une recherche purement exploratoire concernant la dĂ©finition d'une application de rĂ©seaux de neurones Ă base de transistors monoĂ©lectroniques (Single-Electron Transistor, SET). Il dresse un portait de l'Ă©tat de l'art actuel, et met de l'avant la possibilitĂ© d'associer les SET avec la technologie actuelle (Field Electron Transistor, FET). La raison de cette association est que les SET peuvent ĂȘtre perçus comme un moyen de changement de paradigme, c'est-Ă -dire remplacer une fonction CMOS occupant une grande place par un dispositif alternatif prĂ©sentant de meilleures performances ou Ă©quivalentes. Par l'intermĂ©diaire de leurs caractĂ©ristiques Ă©lectriques peu ordinaires au synonyme de"l'effet de blocage de Coulomb", les SET ont le potentiel d'ĂȘtre exploitĂ©s intelligemment afin de tirer profit sur la consommation Ă©nergĂ©tique essentiellement. Cette problĂ©matique est prĂ©sentĂ©e comme une des propositions alternatives"Beyond CMOS" aux termes de la diminution gĂ©omĂ©trique des transistors FET Ă la lumiĂšre de l'ITRS. Cette recherche propose d'exposer des circuits Ă©lectroniques de technologie MOS complĂ©tĂ©s Ă l'aide de SET (circuits hybrides) et de montrer que l'on est capable de les remplacer ou les complĂ©ter (partiellement) dans des architectures Ă rĂ©seau de neurones. Pour cela, des simulations sous logiciel Cadence Environnement permettront de valider le comportement des circuits sur plusieurs critĂšres tels que la vitesse de rĂ©ponse et la consommation Ă©nergĂ©tique, par exemple. En rĂ©sultat, seront proposĂ©es deux architectures Ă rĂ©seaux de neurones de fonctions diffĂ©rentes : une architecture Winner-Take-All et un gĂ©nĂ©rateur de spikes en tension. La premiĂšre Ă©tant inspirĂ©e d'une publication provenant de GUIMARAES et al., veut dĂ©montrer qu'Ă partir d'une architecture SET existante, il est envisageable de se l'approprier et de l'appliquer aux paramĂštres des SET du CRN[indice supĂ©rieur 2] augmentant donc nos chances de pouvoir les concevoir dans notre groupe de recherche. Le second axe est la simulation d'un circuit capable de gĂ©nĂ©rer des signaux Ă spikes sans perte d'information, ce qui requerrait un nombre considĂ©rable de transistors FET sans l'utilisation de SET, mettant donc en valeur la rĂ©duction de composants