Diagnóstico automático de melanoma mediante técnicas modernas de aprendizaje automático

The incidence and mortality rates of skin cancer remain a huge concern in many countries. According to the latest statistics about melanoma skin cancer, only in the Unites States, 7,650 deaths are expected in 2022, which represents 800 and 470 more deaths than 2020 and 2021, respectively. In 2022, melanoma is ranked as the fifth cause of new cases of cancer, with a total of 99,780 people. This illness is mainly diagnosed with a visual inspection of the skin, then, if doubts remain, a dermoscopic analysis is performed. The development of e_ective non-invasive diagnostic tools for the early stages of the illness should increase quality of life, and decrease the required economic resources. The early diagnosis of skin lesions remains a tough task even for expert dermatologists because of the complexity, variability, dubiousness of the symptoms, and similarities between the different categories among skin lesions. To achieve this goal, previous works have shown that early diagnosis from skin images can benefit greatly from using computational methods. Several studies have applied handcrafted-based methods on high quality dermoscopic and histological images, and on top of that, machine learning techniques, such as the k-nearest neighbors approach, support vector machines and random forest. However, one must bear in mind that although the previous extraction of handcrafted features incorporates an important knowledge base into the analysis, the quality of the extracted descriptors relies heavily on the contribution of experts. Lesion segmentation is also performed manually. The above procedures have a common issue: they are time-consuming manual processes prone to errors. Furthermore, an explicit definition of an intuitive and interpretable feature is hardly achievable, since it depends on pixel intensity space and, therefore, they are not invariant regarding the differences in the input images. On the other hand, the use of mobile devices has sharply increased, which offers an almost unlimited source of data. In the past few years, more and more attention has been paid to designing deep learning models for diagnosing melanoma, more specifically Convolutional Neural Networks. This type of model is able to extract and learn high-level features from raw images and/or other data without the intervention of experts. Several studies showed that deep learning models can overcome handcrafted-based methods, and even match the predictive performance of dermatologists. The International Skin Imaging Collaboration encourages the development of methods for digital skin imaging. Every year since 2016 to 2019, a challenge and a conference have been organized, in which more than 185 teams have participated. However, convolutional models present several issues for skin diagnosis. These models can fit on a wide diversity of non-linear data points, being prone to overfitting on datasets with small numbers of training examples per class and, therefore, attaining a poor generalization capacity. On the other hand, this type of model is sensitive to some characteristics in data, such as large inter-class similarities and intra-class variances, variations in viewpoints, changes in lighting conditions, occlusions, and background clutter, which can be mostly found in non-dermoscopic images. These issues represent challenges for the application of automatic diagnosis techniques in the early phases of the illness. As a consequence of the above, the aim of this Ph.D. thesis is to make significant contributions to the automatic diagnosis of melanoma. The proposals aim to avoid overfitting and improve the generalization capacity of deep models, as well as to achieve a more stable learning and better convergence. Bear in mind that research into deep learning commonly requires an overwhelming processing power in order to train complex architectures. For example, when developing NASNet architecture, researchers used 500 x NVidia P100s - each graphic unit cost from $5,899 to$7,374, which represents a total of $2,949,500.00 -$3,687,000.00. Unfortunately, the majority of research groups do not have access to such resources, including ours. In this Ph.D. thesis, the use of several techniques has been explored. First, an extensive experimental study was carried out, which included state-of-the-art models and methods to further increase the performance. Well-known techniques were applied, such as data augmentation and transfer learning. Data augmentation is performed in order to balance out the number of instances per category and act as a regularizer in preventing overfitting in neural networks. On the other hand, transfer learning uses weights of a pre-trained model from another task, as the initial condition for the learning of the target network. Results demonstrate that the automatic diagnosis of melanoma is a complex task. However, different techniques are able to mitigate such issues in some degree. Finally, suggestions are given about how to train convolutional models for melanoma diagnosis and future interesting research lines were presented. Next, the discovery of ensemble-based architectures is tackled by using genetic algorithms. The proposal is able to stabilize the training process. This is made possible by finding sub-optimal combinations of abstract features from the ensemble, which are used to train a convolutional block. Then, several predictive blocks are trained at the same time, and the final diagnosis is achieved by combining all individual predictions. We empirically investigate the benefits of the proposal, which shows better convergence, mitigates the overfitting of the model, and improves the generalization performance. On top of that, the proposed model is available online and can be consulted by experts. The next proposal is focused on designing an advanced architecture capable of fusing classical convolutional blocks and a novel model known as Dynamic Routing Between Capsules. This approach addresses the limitations of convolutional blocks by using a set of neurons instead of an individual neuron in order to represent objects. An implicit description of the objects is learned by each capsule, such as position, size, texture, deformation, and orientation. In addition, a hyper-tuning of the main parameters is carried out in order to ensure e_ective learning under limited training data. An extensive experimental study was conducted where the fusion of both methods outperformed six state-of-the-art models. On the other hand, a robust method for melanoma diagnosis, which is inspired on residual connections and Generative Adversarial Networks, is proposed. The architecture is able to produce plausible photorealistic synthetic 512 x 512 skin images, even with small dermoscopic and non-dermoscopic skin image datasets as problema domains. In this manner, the lack of data, the imbalance problems, and the overfitting issues are tackled. Finally, several convolutional modes are extensively trained and evaluated by using the synthetic images, illustrating its effectiveness in the diagnosis of melanoma. In addition, a framework, which is inspired on Active Learning, is proposed. The batch-based query strategy setting proposed in this work enables a more faster training process by learning about the complexity of the data. Such complexities allow us to adjust the training process after each epoch, which leads the model to achieve better performance in a lower number of iterations compared to random mini-batch sampling. Then, the training method is assessed by analyzing both the informativeness value of each image and the predictive performance of the models. An extensive experimental study is conducted, where models trained with the proposal attain significantly better results than the baseline models. The findings suggest that there is still space for improvement in the diagnosis of skin lesions. Structured laboratory data, unstructured narrative data, and in some cases, audio or observational data, are given by radiologists as key points during the interpretation of the prediction. This is particularly true in the diagnosis of melanoma, where substantial clinical context is often essential. For example, symptoms like itches and several shots of a skin lesion during a period of time proving that the lesion is growing, are very likely to suggest cancer. The use of different types of input data could help to improve the performance of medical predictive models. In this regard, a _rst evolutionary algorithm aimed at exploring multimodal multiclass data has been proposed, which surpassed a single-input model. Furthermore, the predictive features extracted by primary capsules could be used to train other models, such as Support Vector Machine

Análisis explorativo de la seguridad en las redes sociales de los estudiantes de grado medio en la región de El Mante, México.

La presente investigación se fundamenta en que la tecnología es una facilitadora social. Las personastienen cada vez más acceso a las redes sociales, aunque la presencia del conocimiento sobre la seguridady protección es muy escasa. Esto se debe a la falta de información de los usuarios. Este trabajo tienecomo objetivo analizar la percepción que los estudiantes de enseñanza media superior y la sociedad engeneral tienen sobre la privacidad y seguridad que encuentran en el uso de las redes sociales. Para eldesarrollo de la investigación se tomaron algunas pautas de la metodología de Análisis de Redes. Estapermite un análisis de las estructuras sociales, así como determinar alguna de las causas que provocanla inseguridad en las redes sociales y cuáles son los principales usuarios

Innovación en las enseñanzas universitarias: experiencias presentadas en las III Jornadas de Innovación Educativa de la ULL

En este libro se recoge un conjunto de experiencias de innovación educativa desarrolladas en la ULL en el curso 2011-12. Se abordan distintos ámbitos y ramas del conocimiento, y ocupan temáticas variadas que han sido desarrolladas con rigor, y con un claro potencial para su extrapolación a efectos de la mejora educativa en el ámbito universitario. Esta publicación constituye una primera edición de una serie que irá recogiendo las experiencias de innovación educativa de la ULL. Este es un paso relevante para su impulso en nuestra institución, como lo es el de su vinculación con la investigación educativa, para potenciar su publicación en las revistas científicas en este ámbito cada vez más pujante y relevante para las universidades. Sobre todo representan el deseo y el compromiso del profesorado de la ULL para la mejora del proceso educativo mediante la investigación, la evaluación y la reflexión compartida de nuestras prácticas y planteamientos docentes

XVI International Congress of Control Electronics and Telecommunications: "Techno-scientific considerations for a post-pandemic world intensive in knowledge, innovation and sustainable local development"

Este título, sugestivo por los impactos durante la situación de la Covid 19 en el mundo, y que en Colombia lastimosamente han sido muy críticos, permiten asumir la obligada superación de tensiones sociales, políticas, y económicas; pero sobre todo científicas y tecnológicas. Inicialmente, esto supone la existencia de una capacidad de la sociedad colombiana por recuperar su estado inicial después de que haya cesado la perturbación a la que fue sometida por la catastrófica pandemia, y superar ese anterior estado de cosas ya que se encontraban -y aún se encuentran- muchos problemas locales mal resueltos, medianamente resueltos, y muchos sin resolver: es decir, habrá que rediseñar y fortalecer una probada resiliencia social existente - producto del prolongado conflicto social colombiano superado parcialmente por un proceso de paz exitoso - desde la tecnociencia local; como lo indicaba Markus Brunnermeier - economista alemán y catedrático de economía de la Universidad de Princeton- en su libro The Resilient Society…La cuestión no es preveerlo todo sino poder reaccionar…aprender a recuperarse rápido.This title, suggestive of the impacts during the Covid 19 situation in the world, and which have unfortunately been very critical in Colombia, allows us to assume the obligatory overcoming of social, political, and economic tensions; but above all scientific and technological. Initially, this supposes the existence of a capacity of Colombian society to recover its initial state after the disturbance to which it was subjected by the catastrophic pandemic has ceased, and to overcome that previous state of affairs since it was found -and still is find - many local problems poorly resolved, moderately resolved, and many unresolved: that is, an existing social resilience test will have to be redesigned and strengthened - product of the prolonged Colombian social conflict partially overcome by a successful peace process - from local technoscience; As Markus Brunnermeier - German economist and professor of economics at Princeton University - indicates in his book The Resilient Society...The question is not to foresee everything but to be able to react...learn to recover quickly.Bogot

Añadiendo Capacidades de Búsqueda a Entornos de Desarrollo Integrado para la Enseñanza y Aprendizaje de la Programación en Ambientes Remotos

La comunidad de varios Entornos de Desarrollo Integrado (IDEs) ha mostrado interés en la construcción de herramientas con soporte para la colaboración de los desarrolladores, pero sin hacer hincapié en la búsqueda de código fuente. En este trabajo se presenta un plug-in para los IDEs NetBeans y Eclipse en el contexto académico como una alternativa a esta disyuntiva, con el cual se realizó una experimentación con dos grupos de estudiantes que arrojó como conclusión que con la aplicación de técnicas de búsqueda en los IDEs, se pueden obtener mejores resultados respecto a herramientas de búsqueda de código fuente centradas en una interacción individual y los IDEs por separado

Adding Search Features to Integrated Development Environments for Teaching and Learning Programming in Remote Scenarios

La comunidad de varios Entornos de Desarrollo Integrado (IDEs) ha mostrado interés en la construcción de herramientas con soporte para la colaboración de los desarrolladores, pero sin hacer hincapié en la búsqueda de código fuente. En este trabajo se presenta un plug-in para los IDEs NetBeans y Eclipse en el contexto académico como una alternativa a esta disyuntiva, con el cual se realizó una experimentación con dos grupos de estudiantes que arrojó como conclusión que con la aplicación de técnicas de búsqueda en los IDEs, se pueden obtener mejores resultados respecto a herramientas de búsqueda de código fuente centradas en una interacción individual y los IDEs por separadoThe community of many Integrated Development Environments (IDEs) has shown interest to develop tools with support for the collaboration among developers, but without doing emphasis in source code search mechanisms. In this work we propose a NetBeans and Eclipse plug-in for the academic context as an alternative to the problem mentioned above. Also, we carry out an experimentation with two groups of students, that showed as main conclusion that with the integration of search techniques inside IDEs we can obtain better results in relation to use search tools and IDEs separatel

Campus virtuales : revista científica iberoamericana de tecnología educativa

Resumen tomado de la publicaciónLa comunidad de varios Entornos de Desarrollo Integrado (IDEs) ha mostrado interés en la construcción de herramientas con soporte para la colaboración de los desarrolladores, pero sin hacer hincapié en la búsqueda de código fuente. Se presenta un plug-in para los IDEs NetBeans y Eclipse en el contexto académico como una alternativa a esta disyuntiva, con el cual se realizó una experimentación con dos grupos de estudiantes que arrojó como conclusión que con la aplicación de técnicas de búsqueda en los IDEs, se pueden obtener mejores resultados respecto a herramientas de búsqueda de código fuente centradas en una interacción individual y los IDEs por separadoES

Empleo de la cáscara de arroz en la fundición de piezas de acero al carbono//Using of rice husk in the carbon steel casting parts process

Los materiales auxiliares desempeñan un papel importante en el aumento de la eficiencia tecnológica del proceso de fundición de piezas de acero al carbono. En este artículo se exponen los primeros resultados del empleo de la cáscara de arroz como material termoaislante en la obtención de piezas fundidas de acero al carbono. En los experimentos se evaluó la influencia  de seis combinaciones de las variables espesor de pared del casquillo y capa de cobertura. En la confección de los casquillos se utilizó cáscara de arroz triturada, la que posteriormente fue aglutinada con silicato de sodio, apisonada y endurecida con CO2, mientras que la cobertura se utilizó sin procesamiento previo. El mayor nivel de entrega de acero se obtuvo al emplear un espesor de casquillo de 65 mm y una altura de cobertura de 85 mm. El valor del ASAF generado por las variantes experimentales resultó igual o inferior a 0,48. Palabras claves: casquillo termoaislante, polvo de cobertura, cáscara de arroz, acero fundido.______________________________________________________________________________ Abstract Feeding auxiliary materials perform a very important role in improves technological efficiency of carbon steel casting parts process. In this article are exposing the first results in the rice husk using as an insulating material in such process. The variables sleeve thickness and covering thickness’ influence were evaluated in six combinations by means of experiments. In sleeves preparation was used crushed rice husk, which was agglutinated with sodium silicate, compacted and hardened with CO2, meanwhile as covering it was uses without previous preparation. The mayor liquid steel delivering level was get employing 65 mm sleeve thickness and 85 mm covering thickness. The ASAF value generated for experimental variants was equal or inferior to 0.48. Key words: insulating sleeve, riser sleeve, hot topping, rice husk, steel cast.</p

Efecto de la adición de caliza sobre el metal depositado por arco sumergido

Se evaluó el efecto del incremento de las adiciones de caliza en laobtención de un fundente al manganeso sobre la composición delmetal depositado por arco sumergido (proceso SAW). La adición decaliza se realizó manteniendo constante la relación porcentualMnO/SiO2 del sistema de óxidos del fundente. Con el aumento de labasicidad se logró intensificar la actividad termodinámica del MnO ydisminuir la del SiO2, favoreciéndose la transferencia del manganeso al metal depositado, a la vez que se atenúa la del silicio, el azufre, el fósforo y el carbono permanece prácticamente inalterable. Esto posibilita el empleo de un alambre de bajo manganeso durante lasoldadura de aceros de baja aleación con proceso SAW

El papel del Derecho en el cambio material y simbólico del paisaje colombiano 1850-1930* The role of Law in the material and symbolic change of the Colombian landscape 1850-1930

Este artículo entrelaza diferentes aspectos de la transformación del paisaje de Colombia, simbólico y material, desde mediados del siglo XIX hasta las primeras tres décadas del siglo XX. Para ello, describe, evalúa y analiza el sistema jurídico, particularmente, asociado a la regulación y codificación de la propiedad privada de la tierra, así como los aspectos públicos de las leyes de baldíos. No presenta un listado exhaustivo de la normatividad promulgada en la época sino la forma cómo en la realidad colombiana - territorialmente fragmentada y heterogéneamente apropiada - el Derecho contribuye a la transformación del paisaje. El Derecho del Estado tendió a construir una especie de monismo jurídico sobre la pluralidad de órdenes jurídicos que heredó de la colonia y las primeras décadas republicanas. De este modo, cuestiona tanto las visones que se basan en el derecho formalista y positivo, como las posiciones de la sociología jurídica que consideran que sólo hay un abismo entre la realidad social y la jurídica. Apunta a mostrar el papel simbólico, más que ideológico, del Derecho en el cambio ambiental pero, a su vez reconoce los cambios materiales que el proyecto de Derecho basado en el predominio de la propiedad privada como Derecho absoluto engendró en esta época.<br>Este artigo entrelaça diferentes aspectos da transformação da paisagem da Colômbia, simbólica e material, desde meados do século XIX até as primeiras três décadas do século XX. Para tanto, descreve, avalia e analisa o sistema jurídico, particularmente associado à regulamentação e codificação da propriedade privada da terra, assim como os aspectos públicos das leis de terras devolutas. Não apresenta uma lista exaustiva da normatividade promulgada na época, mas a forma como - na realidade colombiana, territorialmente fragmentada e heterogeneamente apropriada - o Direito contribui para a transformação da paisagem. O Direito de Estado tendeu a construir uma espécie de monismo jurídico sobre a pluralidade de ordens jurídicas herdadas da colônia e das primeiras décadas republicanas. Deste modo, questionam-se tanto as visões baseadas no direito formalista e positivo, como as posições da sociologia jurídica, que consideram tão somente um abismo entre a realidade social e a jurídica. Sublinha-se o papel simbólico, mais que ideológico, do direito na transformação ambiental mas, por sua vez, reconhece as transformações materiais então engendradas no projeto de direito baseado no predomínio da propriedade privada como Direito absoluto.<br>This article entangles several aspects of the transformation of the Colombian landscape in both, its material and symbolic faces, since the middle of the nineteenth until the third decade of the twentieth century. Consequently, it describes, and analyses the legal system, particularly those aspects related to the private and the public property of land. It argues first, about the importance of the Civil Code to understand the whole nineteenth century project; and second, about "waste lands" (baldíos: public lands without legal proprietors) which are of crucial interest to understand the whole process. It thinks about Law, not simply as a written norm, but in its environmental interaction. It also goes beyond the apparent chasm posed by sociology of Law as "law in books and law in action". It concludes that the dualistic "Law of the State" tended - unfolded as private and public Law - to monopolize the legal phenomenon engendering symbolic and material changes of a landscape that was territorially fragmented and heterogeneously appropriated