On the regulator problem for linear systems over rings and algebras

[EN] The regulator problem is solvable for a linear dynamical system Σ if and only if Σ is both pole assignable and state estimable. In this case, Σ is a canonical system (i.e., reachable and observable). When the ring R is a field or a Noetherian total ring of fractions the converse is true. Commutative rings which have the property that the regulator problem is solvable for every canonical system (RP-rings) are characterized as the class of rings where every observable system is state estimable (SE-rings), and this class is shown to be equal to the class of rings where every reachable system is pole-assignable (PA-rings) and the dual of a canonical system is also canonical (DP-rings).SIThis research was partially supported by RIASC, Research Institute of Applied Sciences and Cybersecurity (riasc.unileon.es)

Rosenbrock's theorem for systems over von Neumann regular rings

pp. 122-130If is a finite system over a commutative von Neumann regular ring R, the problem of searching for a matrix F such that the pencil has some prescribed Smith normal form is reduced to the case where R is a field, a problem which for controllable systems is described by a well-known theorem of Rosenbrock on pole assignment [12], and was then generalized to noncontrollable pairs [14]. It this paper, von Neumann regular rings are characterized as the class of commutative rings for which the solution of the above problem over the ring is equivalent to its solution in each residue field.S

Evaluación de la calidad de vida en personas drogodopendientes mediante el modelo de Rasch

La Escala GENCAT aparece como el único instrumento que permite evaluar la calidad de vida individual de personas con drogodependencias desde una perspectiva diferente a la de calidad de vida relacionada con la salud (CVRS). Dado que las propiedades psicométricas de la mencionada escala sólo se han estudiado para la muestra general de usuarios de servicios sociales, este estudio tiene como objetivo analizar su fiabilidad y validez en un grupo específico de personas con drogodependencias. Para ello, se aplicó a 75 drogodependientes usuarios de servicios sociales en Cataluña. Los datos obtenidos permiten concluir que la escala, para este colectivo, presenta una adecuada consistencia interna (que supera en algunos casos la obtenida para la muestra general) según la Teoría Clásica de los Tests. Además, se observó que el ajuste medio de los ítems al modelo y la fiabilidad promedio de las estimaciones de los ítems fueron altos según el modelo de Rasch, aunque los índices de fiabilidad de las personas resultaron más moderados en la mayoría de las subescalas y deficiente en el caso de la dimensión bienestar físico. Se concluye que, aunque la escala es válida y fiable en términos generales, es aconsejable una revisión de la dimensión mencionada

Predicting length of stay across hospital departments

The length of hospital stay and its implications have a significant economic and human impact. As a consequence, the prediction of that key parameter has been subject to previous research in recent years. Most previous work has analysed length of stay in particular hospital departments within specific study groups, which has resulted in successful prediction rates, but only occasionally reporting predictive patterns. In this work we report a predictive model for length of stay (LOS) together with a study of trends and patterns that support a better understanding on how LOS varies across different hospital departments and specialties. We also analyse in which hospital departments the prediction of LOS from patient data is more insightful. After estimating predictions rates, several patterns were found; those patterns allowed, for instance, to determine how to increase prediction accuracy in women admitted to the emergency room for enteritis problems. Overall, concerning these recognised patterns, the results are up to 21.61% better than the results with baseline machine learning algorithms in terms of error rate calculation, and up to 23.83% in terms of success rate in the number of predicted which is useful to guide the decision on where to focus attention in predicting LOS

Traceability for trustworthy AI: a review of models and tools

Traceability is considered a key requirement for trustworthy artificial intelligence (AI), related to the need to maintain a complete account of the provenance of data, processes, and artifacts involved in the production of an AI model. Traceability in AI shares part of its scope with general purpose recommendations for provenance as W3C PROV, and it is also supported to different extents by specific tools used by practitioners as part of their efforts in making data analytic processes reproducible or repeatable. Here, we review relevant tools, practices, and data models for traceability in their connection to building AI models and systems. We also propose some minimal requirements to consider a model traceable according to the assessment list of the High-Level Expert Group on AI. Our review shows how, although a good number of reproducibility tools are available, a common approach is currently lacking, together with the need for shared semantics. Besides, we have detected that some tools have either not achieved full maturity, or are already falling into obsolescence or in a state of near abandonment by its developers, which might compromise the reproducibility of the research trusted to them

Development of a support needs assessment scale for children and adolescents with intellectual disabilities

RESUMEN: El artículo presentado está orientado al desarrollo de una escala de evaluación de necesidades apoyos para niños y adolescentes (5-16 años) con discapacidad intelectual. Esta herramienta es coherente con la concepción más reciente de discapacidad intelectual y se desarrolla en castellano a partir de una propuesta internacional iniciada desde la Asociación Americana de Discapacidades Intelectuales y del Desarrollo (AAIDD). El foco principal de este estudio es analizar las características psicométricas de la escala en el contexto español. El instrumento ha sido aplicado a una muestra piloto de 143 niños y adolescentes con discapacidad intelectual y analizado bajo los supuestos de la Teoría de Respuesta a los Ítems (TRI); concretamente, se han asumido los supuestos del Modelo de Escalas de Clasificación. Los resultados alcanzados muestran evidencias iniciales de la fiabilidad y validez de la escala, así como el adecuado ajuste de los datos al modelo propuesto.ABSTRACT: The paper presented is focused on the development of a scale for assessing support needs for children and adolescents with intellectual disabilities. This tool adheres to the most recent conception of intellectual disability and it is being developed in Spanish following the international proposal initiated by the American Association of Intellectual and Developmental Disabilities (AAIDD). The main focus of the research is to analyze, the psychometric characteristics of the scale within the Spanish context. The tool has been used so far with a pilot sample of 143 people (both children and adolescents) with intellectual disabilities and it has also been according to the framework of Item Response Theory (IRT), specifically the assumptions of the Rating Scale Model (RSM) have been taken into account. The results achieved so far show preliminary evidence of the reliability and validity of the scale, as well as the adequate adjustment of the data to the proposed model.Este artículo se ha escrito en el marco del proyecto de investigación I+D PSI2012-36278 financiado por el Ministerio de Economía y Competitividad

Evolution and prospects of the Comprehensive R Archive Network (CRAN) package ecosystem

Free and open source software package ecosystems have existed for a long time, but such collaborative development practice has surged in recent years. One of the oldest and most popular package ecosystems is Comprehensive R Archive Network (CRAN), the repository of packages of the statistical language R, a popular statistical computing environment. CRAN stores a large number of packages that are updated regularly and depend on many other packages in a complex graph of relations. As the repository grows, its sustainability could be threatened by that complexity or nonuniform evolution of some packages. This paper provides an empirical analysis of the evolution of the CRAN repository in the last 20 years, considering the laws of software evolution and the effect of CRAN's policies on such development. Results show how the progress of CRAN is consistent with the laws of continuous growth and change and how there seems to be a relevant increase in complexity in recent years. Significant challenges are raising related to the scale and scope of software package managers and the services they provide; understanding how they change over time and what might endanger their sustainability are key factors for their future improvement, maintenance, policies, and, eventually, sustainability of the ecosystem

Herramientas para la producción, el fortalecimiento y la difusión de revistas académicas mexicanas en línea (LATINDEX-UNAM)

En la Universidad Nacional Autónoma de México (UNAM), debido a iniciativas institucionales como Latindex y el Portal de Revistas Científicas y Arbitradas de la UNAM, actualmente, se cuenta con personal académico con los conocimientos técnicos y la experiencia necesaria para poder colaborar con otras universidades de México en la adopción y aplicación de buenas prácticas editoriales, así como en la implementación y administración de herramientas tecnológicas, y de esta manera, contribuir a lograr una mayor visibilidad y posicionamiento de las revistas académicas mexicanas. Con base en lo anterior, en el primer trimestre de 2012 se presentó un anteproyecto al Consejo Nacional de Ciencia y Tecnología (CONACYT), con el objetivo de contribuir al impulso y fortalecimiento de la producción y la difusión de revistas académicas en línea de universidades públicas mexicanas, a través de promover la adopción de buenas prácticas editoriales y del uso y aprovechamiento de las TIC. Una vez evaluado el anteproyecto por los órganos correspondientes, en marzo de 2012 fue aprobado para su desarrollo con el financiamiento del CONACYT para el periodo del 18 de mayo al 31 de diciembre de 2013, quedando como responsable del mismo la UNAM. En cumplimiento de los compromisos asumidos por la UNAM para el desarrollo del proyecto, en este documento, se presenta un informe general de las actividades y resultados obtenidos durante el desarrollo del proyecto, así como un anexo sobre el ejercicio de los recursos otorgados por el CONACYT

Authority-based conversation tracking in Twitter: an unattended methodological approach

Twitter is undoubtedly one of the most widely used data sources to analyze human communication. The literature is full of examples where Twitter is accessed, and data are downloaded as the previous step to a more in-depth analysis in a wide variety of knowledge areas. Unfortunately, the extraction of relevant information from the opinions that users freely express in Twitter is complicated, both because of the volume generated—more than 6000 tweets per second—and the difficulties related to filtering out only what is pertinent to our research. Inspired by the fact that a large part of users use Twitter to communicate or receive political information, we created a method that allows for the monitoring of a set of users (which we will call authorities) and the tracking of the information published by them about an event. Our approach consists of dynamically and automatically monitoring the hottest topics among all the conversations where the authorities are involved, and retrieving the tweets in connection with those topics, filtering other conversations out. Although our case study involves the method being applied to the political discussions held during the Spanish general, local, and European elections of April/May 2019, the method is equally applicable to many other contexts, such as sporting events, marketing campaigns, or health crises