Perceptrons
MLPInit: Embarrassingly Simple GNN Training Acceleration with MLP Initialization
Han, Xiaotian, Zhao, Tong, Liu, Yozen, Hu, Xia, Shah, Neil
Training graph neural networks (GNNs) on large graphs is complex and extremely time consuming. This is attributed to overheads caused by sparse matrix multiplication, which are sidestepped when training multi-layer perceptrons (MLPs) with only node features. MLPs, by ignoring graph context, are simple and faster for graph data, however they usually sacrifice prediction accuracy, limiting their applications for graph data. We observe that for most message passing-based GNNs, we can trivially derive an analog MLP (we call this a PeerMLP) with an equivalent weight space, by setting the trainable parameters with the same shapes, making us curious about \textbf{\emph{how do GNNs using weights from a fully trained PeerMLP perform?}} Surprisingly, we find that GNNs initialized with such weights significantly outperform their PeerMLPs, motivating us to use PeerMLP training as a precursor, initialization step to GNN training. To this end, we propose an embarrassingly simple, yet hugely effective initialization method for GNN training acceleration, called MLPInit. Our extensive experiments on multiple large-scale graph datasets with diverse GNN architectures validate that MLPInit can accelerate the training of GNNs (up to 33X speedup on OGB-Products) and often improve prediction performance (e.g., up to $7.97\%$ improvement for GraphSAGE across $7$ datasets for node classification, and up to $17.81\%$ improvement across $4$ datasets for link prediction on metric Hits@10). The code is available at \href{https://github.com/snap-research/MLPInit-for-GNNs}.
Speech Recognition Experiments with Perceptrons
Artificial neural networks (ANNs) are capable of accurate recognition of simple speech vocabularies such as isolated digits [1]. This paper looks at two more difficult vocabularies, the alphabetic E-set and a set of polysyllabic words. The E-set is difficult because it contains weak discriminants and polysyllables are difficult because of timing variation. Polysyllabic word recognition is aided by a time pre-alignment technique based on dynamic pro(cid:173) gramming and E-set recognition is improved by focusing attention. Recogni(cid:173) tion accuracies are better than 98% for both vocabularies when implemented with a single layer perceptron.
Performance of Synthetic Neural Network Classification of Noisy Radar Signals
This study evaluates the performance of the multilayer-perceptron and the frequency-sensitive competitive learning network in iden(cid:173) tifying five commercial aircraft from radar backscatter measure(cid:173) ments. The performance of the neural network classifiers is com(cid:173) pared with that of the nearest-neighbor and maximum-likelihood classifiers. Our results indicate that for this problem, the neural network classifiers are relatively insensitive to changes in the net(cid:173) work topology, and to the noise level in the training data. While, for this problem, the traditional algorithms outperform these sim(cid:173) ple neural classifiers, we feel that neural networks show the poten(cid:173) tial for improved performance.
Neural Net Receivers in Multiple Access-Communications
The application of neural networks to the demodulation of spread-spectrum signals in a multiple-access environment is considered. This study is motivated in large part by the fact that, in a multiuser system, the conventional (matched fil(cid:173) ter) receiver suffers severe performance degradation as the relative powers of the interfering signals become large (the "near-far" problem). Furthermore, the optimum receiver, which alleviates the near-far problem, is too complex to be of practical use. Receivers based on multi-layer perceptrons are considered as a simple and robust alternative to the opti(cid:173) mum solution. The optimum receiver is used to benchmark the performance of the neural net receiver; in particular, it is proven to be instrumental in identifying the decision regions of the neural networks.
Adaptive Neural Net Preprocessing for Signal Detection in Non-Gaussian Noise
A nonlinearity is required before matched filtering in mInimum error receivers when additive noise is present which is impulsive and highly non-Gaussian. Experiments were performed to determine whether the correct clipping nonlinearity could be provided by a single-input single(cid:173) output multi-layer perceptron trained with back propagation. It was found that a multi-layer perceptron with one input and output node, 20 nodes in the first hidden layer, and 5 nodes in the second hidden layer could be trained to provide a clipping nonlinearity with fewer than 5,000 presentations of noiseless and corrupted waveform samples. A network trained at a relatively high signal-to-noise (SIN) ratio and then used as a front end for a linear matched filter detector greatly reduced the probability of error. The clipping nonlinearity formed by this network was similar to that used in current receivers designed for impulsive noise and provided similar substantial improvements in performance.
Training Multilayer Perceptrons with the Extended Kalman Algorithm
A large fraction of recent work in artificial neural nets uses multilayer perceptrons the back-propagation algorithm described by Rumelhart et. This algorithm converges slowly for large or complex problems such as speech recognition, where thousands of iterations may be needed for convergence even with small data sets. In this paper, we show that training multilayer perceptrons is an identification problem for a nonlinear dynamic system which can be solved using the Extended Kalman Algorithm. Although computationally complex, the Kalman algorithm usually converges in a few the algorithm and compare it with back-propagation using two(cid:173) dimensional examples.
Applications of Error Back-Propagation to Phonetic Classification
This paper is concerced with the use of error back-propagation in phonetic classification. Our objective is to investigate the ba(cid:173) sic characteristics of back-propagation, and study how the frame(cid:173) work of multi-layer perceptrons can be exploited in phonetic recog(cid:173) nition. We explore issues such as integration of heterogeneous sources of information, conditioll that can affect performance of phonetic classification, internal representations, comparisons with traditional pattern classification techniques, comparisons of differ(cid:173) ent error metrics, and initialization of the network. Our investiga(cid:173) tion is performed within a set of experiments that attempts to rec(cid:173) ognize the 16 vowels in American English independent of speaker. Our results are comparable to human performance.
Links Between Markov Models and Multilayer Perceptrons
Hidden Markov models are widely used for automatic speech recog(cid:173) nition. They inherently incorporate the sequential character of the speech signal and are statistically trained. However, the a-priori choice of the model topology limits their flexibility. Another draw(cid:173) back of these models is their weak discriminating power. Multilayer perceptrons are now promising tools in the connectionist approach for classification problems and have already been successfully tested on speech recognition problems. However, the sequential nature of the speech signal remains difficult to handle in that kind of ma(cid:173) chine.
The Boltzmann Perceptron Network: A Multi-Layered Feed-Forward Network Equivalent to the Boltzmann Machine
The concept of the stochastic Boltzmann machine (BM) is auractive for decision making and pattern classification purposes since the probability of attaining the network states is a function of the network energy. Hence, the probability of attaining particular energy minima may be associated with the probabilities of making certain decisions (or classifications). However, because of its stochastic nature, the complexity of the BM is fairly high and therefore such networks are not very likely to be used in practice. In this paper we suggest a way to alleviate this drawback by converting the sto(cid:173) chastic BM into a deterministic network which we call the Boltzmann Per(cid:173) ceptron Network (BPN). The BPN is functionally equivalent to the BM but has a feed-forward structure and low complexity. The conditions under which such a convmion is feasible are given.
The CHIR Algorithm for Feed Forward Networks with Binary Weights
A new learning algorithm, Learning by Choice of Internal Rep(cid:173) resetations (CHIR), was recently introduced. Whereas many algo(cid:173) rithms reduce the learning process to minimizing a cost function over the weights, our method treats the internal representations as the fundamental entities to be determined. The algorithm applies a search procedure in the space of internal representations, and a cooperative adaptation of the weights (e.g. by using the perceptron learning rule). Since the introduction of its basic, single output ver(cid:173) sion, the CHIR algorithm was generalized to train any feed forward network of binary neurons. Here we present the generalised version of the CHIR algorithm, and further demonstrate its versatility by describing how it can be modified in order to train networks with binary ( 1) weights.