Improving classification accuracy of feedforward neural networks for spiking neuromorphic chips

Deep Neural Networks (DNN) achieve human level performance in many image analytics tasks but DNNs are mostly deployed to GPU platforms that consume a considerable amount of power. New hardware platforms using lower precision arithmetic achieve drastic reductions in power consumption. More recently, brain-inspired spiking neuromorphic chips have achieved even lower power consumption, on the order of milliwatts, while still offering real-time processing. However, for deploying DNNs to energy efficient neuromorphic chips the incompatibility between continuous neurons and synaptic weights of traditional DNNs, discrete spiking neurons and synapses of neuromorphic chips need to be overcome. Previous work has achieved this by training a network to learn continuous probabilities, before it is deployed to a neuromorphic architecture, such as IBM TrueNorth Neurosynaptic System, by random sampling these probabilities. The main contribution of this paper is a new learning algorithm that learns a TrueNorth configuration ready for deployment. We achieve this by training directly a binary hardware crossbar that accommodates the TrueNorth axon configuration constrains and we propose a different neuron model. Results of our approach trained on electroencephalogram (EEG) data show a significant improvement with previous work (76% vs 86% accuracy) while maintaining state of the art performance on the MNIST handwritten data set.Comment: IJCAI-2017. arXiv admin note: text overlap with arXiv:1605.0774

Aviat: La lucha de los padres contra la droga

Cinquenes Jornades de Foment de la Investigació de la FCHS (Any 1999-2000

Collocation analysis for UMLS knowledge-based word sense disambiguation

BACKGROUND: The effectiveness of knowledge-based word sense disambiguation (WSD) approaches depends in part on the information available in the reference knowledge resource. Off the shelf, these resources are not optimized for WSD and might lack terms to model the context properly. In addition, they might include noisy terms which contribute to false positives in the disambiguation results. METHODS: We analyzed some collocation types which could improve the performance of knowledge-based disambiguation methods. Collocations are obtained by extracting candidate collocations from MEDLINE and then assigning them to one of the senses of an ambiguous word. We performed this assignment either using semantic group profiles or a knowledge-based disambiguation method. In addition to collocations, we used second-order features from a previously implemented approach.Specifically, we measured the effect of these collocations in two knowledge-based WSD methods. The first method, AEC, uses the knowledge from the UMLS to collect examples from MEDLINE which are used to train a Naïve Bayes approach. The second method, MRD, builds a profile for each candidate sense based on the UMLS and compares the profile to the context of the ambiguous word.We have used two WSD test sets which contain disambiguation cases which are mapped to UMLS concepts. The first one, the NLM WSD set, was developed manually by several domain experts and contains words with high frequency occurrence in MEDLINE. The second one, the MSH WSD set, was developed automatically using the MeSH indexing in MEDLINE. It contains a larger set of words and covers a larger number of UMLS semantic types. RESULTS: The results indicate an improvement after the use of collocations, although the approaches have different performance depending on the data set. In the NLM WSD set, the improvement is larger for the MRD disambiguation method using second-order features. Assignment of collocations to a candidate sense based on UMLS semantic group profiles is more effective in the AEC method.In the MSH WSD set, the increment in performance is modest for all the methods. Collocations combined with the MRD disambiguation method have the best performance. The MRD disambiguation method and second-order features provide an insignificant change in performance. The AEC disambiguation method gives a modest improvement in performance. Assignment of collocations to a candidate sense based on knowledge-based methods has better performance. CONCLUSIONS: Collocations improve the performance of knowledge-based disambiguation methods, although results vary depending on the test set and method used. Generally, the AEC method is sensitive to query drift. Using AEC, just a few selected terms provide a large improvement in disambiguation performance. The MRD method handles noisy terms better but requires a larger set of terms to improve performance

Freemasonry and its social influence in Castellón at the end of the 19th century

The city of Castellón began to hold Masonic workshops during the period called “Sexenio Revolucionario”. In the course of the Restoration, and especially in the 1880s, the structural organisation of Freemasonry became complex, specially the lodges under the auspices of the Great National Orient of Spain. It was then that these actors became the main protagonists of the city’s social networks and even participated directly in local politics within republicanism ranks, although this is not discussed in the article. They controlled social centres, such as the “Casino de Artesanos”. They relied on publications that supported them and had a proper Masonic publication, “La Razón”, that emerged as a defence against anti-Masonic elements evidenced in “La Verdad”, amongst other publications. The more plausible results were the “Exposición de Castellón” in July 1887 and the “Exposición de Salinas” of primary instruction.Durante el Sexenio la ciudad de Castellón comenzó a tener talleres masónicos. En la Restauración, y especialmente en la década de 1880, la organización estructural de la masonería llegó a ser compleja, destacando las logias bajo la obediencia del Gran Oriente Nacional de España. Fue entonces cuando estos actores se convirtieron en protagonistas de las redes sociales de la ciudad e incluso tuvieron una participación directa en política local dentro de las filas del republicanismo, aunque este punto no es tratado en el artículo. Controlaron centros de socialización, como es el caso del Casino de Artesanos. Contaron con publicaciones que les apoyaron y tuvieron una publicación propiamente masónica, La Razón, surgida como defensa de los elementos anti-masónicos evidenciados desde La Verdad, entre otras publicaciones. Los resultados más plausibles fueron la Exposición de Castellón de julio de 1887 y la Exposición de instrucción primaria de Salinas