Learning probability distributions generated by finite-state machines

We review methods for inference of probability distributions generated by probabilistic automata and related models for sequence generation. We focus on methods that can be proved to learn in the inference in the limit and PAC formal models. The methods we review are state merging and state splitting methods for probabilistic deterministic automata and the recently developed spectral method for nondeterministic probabilistic automata. In both cases, we derive them from a high-level algorithm described in terms of the Hankel matrix of the distribution to be learned, given as an oracle, and then describe how to adapt that algorithm to account for the error introduced by a finite sample.Peer ReviewedPostprint (author's final draft

Aplicação de métodos de inspiração biológica em sistemas computacionais

A crescente interactividade e complexidade dos sistemas computacionais tem levado à exploração de métodos alternativos para a abordagem de diferentes tipos de problemas. Particularmente relevante tem sido a utilização de métodos de inspiração biológica em diferentes áreas, desde métodos genéricos, a comportamentos sociais e a emoção artificial. Este trabalho tem por objectivo, o estudo e a aplicação de soluções de inspiração biológica no contexto da implementação de sistemas computacionais capazes de navegação autónoma. O trabalho envolve três vertentes principais: (i) estudo de abordagens de base biológica para resolução de problemas no âmbito de sistemas computacionais; (ii) estudo e concepção de uma abordagem de inspiração biológica para implementação de sistemas computacionais capazes de navegação autónoma; (iii) concepção e implementação de um protótipo ilustrativo da abordagem proposta

Improvements on the KNN classifier

Dissertação para obtenção do Grau de Mestre em Engenharia InformáticaThe object classification is an important area within the artificial intelligence and its application extends to various areas, whether or not in the branch of science. Among the other classifiers, the K-nearest neighbor (KNN) is among the most simple and accurate especially in environments where the data distribution is unknown or apparently not parameterizable. This algorithm assigns the classifying element the major class in the K nearest neighbors. According to the original algorithm, this classification implies the calculation of the distances between the classifying instance and each one of the training objects. If on the one hand, having an extensive training set is an element of importance in order to obtain a high accuracy, on the other hand, it makes the classification of each object slower due to its lazy-learning algorithm nature. Indeed, this algorithm does not provide any means of storing information about the previous calculated classifications,making the calculation of the classification of two equal instances mandatory. In a way, it may be said that this classifier does not learn. This dissertation focuses on the lazy-learning fragility and intends to propose a solution that transforms the KNNinto an eager-learning classifier. In other words, it is intended that the algorithm learns effectively with the training set, thus avoiding redundant calculations. In the context of the proposed change in the algorithm, it is important to highlight the attributes that most characterize the objects according to their discriminating power. In this framework, there will be a study regarding the implementation of these transformations on data of different types: continuous and/or categorical

Rheumatoid arthritis and Hailey-Hailey disease treated with methotrexate

Publisher Copyright: © 2022 The Authors. International Journal of Rheumatic Diseases published by Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.We report a rare case of long-standing Hailey-Hailey disease in a Caucasian Portuguese 69-year-old woman, recently diagnosed with rheumatoid arthritis. The patient's skin lesions remained active and exudative despite topical and oral treatments with corticosteroids, tetracyclines, antifungals, and oral treatment with azathioprine. After introduction of methotrexate for rheumatoid arthritis treatment, the skin lesions regressed, with significant impact on the patient's quality of life. This case report supports the clinical evidence of methotrexate's potential role in Hailey-Hailey disease treatment.publishersversionepub_ahead_of_prin

Business Model Options for Antibiotics: Learning from Other Industries

As resistance to antibiotics continues to grow, there is a well-recognized misalignment between the clinical need for new antibiotics and the incentives for their development. The returns from investment in antibiotics research and development (R&D) are perceived as too small. Partly as a result, the number of large multinational companies researching antibiotics has fallen drastically in the past 20 years and few high-quality antibiotics have been developed. In looking at the antimicrobial resistance (AMR) situation, we were aware that other industries have faced conceptually similar challenges and that they might offer helpful lessons and possible solutions that could be adapted to the problems of antimicrobial R&D. Our focus was particularly on learning about models in which the incentive for R&D is delinked from the volume of sales. A Big Innovation Centre and Chatham House workshop brought together on 1 September 2014 six companies that are members of the Big Innovation Centre: BAE Systems (defence), Allianz (insurance), Barclays Bank (finance), EDF Energy (energy), Dun & Bradstreet (corporate information) and Knowledge Unlatched (academic publishing). These companies presented business and incentivization models they had implemented or devised that could be explored further for their applicability to antibiotics R&D. It was made clear to them that any models shared might be adapted so that they a) provide the pharmaceutical industry with an incentive to invest in antibiotics R&D, b) offer insight to health services about how to fund and to maintain the availability of appropriate antibiotics and c) ensure that both new and existing antibiotics are used appropriately and wisely. Learning from other industries has been a very fruitful exercise. They have offered a different perspective on how to tackle the AMR issue and have provided relevant analogies to consider. This research report offers a number of innovative models and ideas that address many of the critical questions facing policy-makers in the EU and the US as they seek solutions. It also contributes to key new initiatives globally and in Europe and the US specifically, including the World Health Organization’s Global Strategy on AMR, the Innovative Medicines Initiative DRIVE-AB project in the EU, the UK’s Review on Antimicrobial Resistance and, in the US, the President’s Advisory Council and the National Strategy for Combating Antibiotic-Resistant Bacteria. This report highlights important lessons about how these other industries have adapted to diverse challenges in their environment. Based on this work and on our own review over the past few months, we see a clear need for a ‘bucket’ of various funding mechanisms that can exist in parallel. There should be separate funding mechanisms in place during the R&D phase of developing an antibiotic and a different mechanism to fund the maintenance, delivery and distribution of the antibiotic after regulatory approval. The report articulates three essential messages: (1) Global collaboration is required on a scale not seen before in relation to antimicrobial resistance. Many independent initiatives are under way nationally and regionally, but they need to be brought together in a concerted worldwide effort to engage on a global scale. The report is designed to help bridge these various efforts and move towards consensus on global action. We propose four initiatives: a. Creating a global antibiotics public-private partnership (GAPPP). A GAPPP should involve private companies, academic institutions and public bodies. It must be a sustainable, independent and self-funding operation with a focus on the research and early development of antibiotics in response to identified global public health needs. b. Creating a global antibiotics fund (GAF), which would be set up to be an over-arching umbrella fund (potentially consolidating all the pre-existing small funds that exist globally). It could exist alongside or in collaboration with major existing funding sources, such as BARDA and IMI, that have very pre- defined targets for funding. A GAF would provide monetary support to a GAPPP in order to enable its R&D effort. A GAF would work with existing funders for better awareness of the work each is supporting and for collaboration in funding priorities, options and courses of action. Ultimately, proposals for a GAPPP and a GAF are a possible way forward to pool skills, resources and funding so as to ensure a sustainable long-term solution. c. Exploring the Gavi (the Vaccine Alliance)-type model and determining whether or not an independent global body should serve as the global procurement and distribution entity for antibiotics. d. Becoming better stewards of antibiotics, as they are valuable drugs. Otherwise, boosting the production of new antibiotics will be futile. Antibiotics must be used appropriately everywhere around the globe. A worldwide effort to conserve them and to ensure appropriate access and use requires international coordination and the participation of every country. Some form of an international treaty or framework agreement is called for. (2) There is a need to explore ‘service-availability’/’option-to-use’ types of agreements/contracts between developers/manufacturers and health care systems as a means to support the ‘delinkage’ concept. As in the defence sector, products are developed but kept on the shelf, maintained and ready when needed, including all the services to deliver them effectively and efficiently. Long-term contracts with customers ensure that the services they require are available when needed. Innovators of new antibiotics should not be rewarded with the traditional ‘price x volume’ model but should focus more on delivering the product, resources and services when needed. Governments would pay an annual ‘service-availability’ fee/premium delinked from the volume of sales. Lessons from the insurance industry indicate how these annual ‘premiums’ could be calculated. (3) There is a need to engage customers (in the broadest sense) and ensure that the right incentives, both financial and non-financial, are aligned from the bench to the bedside. We should not focus on incentives just for the pharmaceutical companies; we must include prescribers, health systems, patients and all other stakeholders

Personalidad y consumo de alcohol en adolescentes

Decenes Jornades de Foment de la Investigació de la FCHS (Any 2004-2005)El alcohol es una de las sustancias adictivas con unos niveles de prevalencia más altos, tanto en jóvenes como en adultos. Existe evidencia de que las personas más impulsivas y / o desinhibidas tienden a consumir más cantidad de alcohol, de forma más frecuente, tienden a consumir alcohol por primera vez a una edad más temprana, tienen la primera borrachera de más jóvenes, y tienen mayor probabilidad de desarrollar alcoholismo que las personas menos impulsivas y / o desinhibidas. El objetivo del presente estudio es investigar la relación de los rasgos impulsividad / desinhibición recogidos en el modelo de personalidad de Costa y McCrae y distintos patrones de consumo de alcohol en adolescentes. Mediante análisis de correlación concluimos que las dimensiones de personalidad relacionadas con el rasgo impulsividad / desinhibición fueron las más importantes para explicar parte de la varianza de las distintas variables del consumo de alcohol en los adolescentes

Red nomológica de las dimensiones de personalidad del modelo de Costa y Mccrae en adolescentes

Decenes Jornades de Foment de la Investigació de la FCHS (Any 2004-2005)Se estudió la red nomológica que forma el modelo de Costa y McCrae (1992) en relación con los modelos de Cloninger (1986; 1998) y de Gray (1981; 1999) en la adolescencia, a partir de estudios realizados en muestras de adultos normales (Cloninger, 1994; O’Gorman, 2002; Moya et al., 2004). Se utilizó el JNEO PI-R (Ortet et al., 2003; Ruipérez et al., 2003), el TCI-60-J (adaptación para adolescentes de la traducción del TCI), y el SCSR-S (Torrubia et al., 2003), en una muestra de 267 adolescentes. Los resultados indicaron que la red nomológica del modelo de Costa y McCrae hallada en adultos se reproduce también en adolescentes

Que decir sea suficiente

Libro reseñado: Perder la locura. Laura Latiff. Valparaíso, Granada (España), 2022, 72 pp