4,052 research outputs found
The Power of Linear Recurrent Neural Networks
Recurrent neural networks are a powerful means to cope with time series. We
show how a type of linearly activated recurrent neural networks, which we call
predictive neural networks, can approximate any time-dependent function f(t)
given by a number of function values. The approximation can effectively be
learned by simply solving a linear equation system; no backpropagation or
similar methods are needed. Furthermore, the network size can be reduced by
taking only most relevant components. Thus, in contrast to others, our approach
not only learns network weights but also the network architecture. The networks
have interesting properties: They end up in ellipse trajectories in the long
run and allow the prediction of further values and compact representations of
functions. We demonstrate this by several experiments, among them multiple
superimposed oscillators (MSO), robotic soccer, and predicting stock prices.
Predictive neural networks outperform the previous state-of-the-art for the MSO
task with a minimal number of units.Comment: 22 pages, 14 figures and tables, revised implementatio
Improving neural networks by preventing co-adaptation of feature detectors
When a large feedforward neural network is trained on a small training set,
it typically performs poorly on held-out test data. This "overfitting" is
greatly reduced by randomly omitting half of the feature detectors on each
training case. This prevents complex co-adaptations in which a feature detector
is only helpful in the context of several other specific feature detectors.
Instead, each neuron learns to detect a feature that is generally helpful for
producing the correct answer given the combinatorially large variety of
internal contexts in which it must operate. Random "dropout" gives big
improvements on many benchmark tasks and sets new records for speech and object
recognition
Metaheuristic design of feedforward neural networks: a review of two decades of research
Over the past two decades, the feedforward neural network (FNN) optimization has been a key interest among the researchers and practitioners of multiple disciplines. The FNN optimization is often viewed from the various perspectives: the optimization of weights, network architecture, activation nodes, learning parameters, learning environment, etc. Researchers adopted such different viewpoints mainly to improve the FNN's generalization ability. The gradient-descent algorithm such as backpropagation has been widely applied to optimize the FNNs. Its success is evident from the FNN's application to numerous real-world problems. However, due to the limitations of the gradient-based optimization methods, the metaheuristic algorithms including the evolutionary algorithms, swarm intelligence, etc., are still being widely explored by the researchers aiming to obtain generalized FNN for a given problem. This article attempts to summarize a broad spectrum of FNN optimization methodologies including conventional and metaheuristic approaches. This article also tries to connect various research directions emerged out of the FNN optimization practices, such as evolving neural network (NN), cooperative coevolution NN, complex-valued NN, deep learning, extreme learning machine, quantum NN, etc. Additionally, it provides interesting research challenges for future research to cope-up with the present information processing era
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