Model Evaluation Based on the Distribution of Estimated Absolute Prediction Error

The construction of a reliable, practically useful prediction rule for future response is heavily dependent on the "adequacy" of the fitted regression model. In this article, we consider the absolute prediction error, the expected value of the absolute difference between the future and predicted responses, as the model evaluation criterion. This prediction error is easier to interpret than the average squared error and is equivalent to the mis-classification error for the binary outcome. We show that the distributions of the apparent error and its cross-validation counterparts are approximately normal even under a misspecified fitted model. When the prediction rule is "unsmooth", the variance of the above normal distribution can be estimated well via a perturbation-resampling method. We also show how to approximate the distribution of the difference of the estimated prediction errors from two competing models. With two real examples, we demonstrate that the resulting interval estimates for prediction errors provide much more information about model adequacy than the point estimates alone.

Evaluating Prediction Rules for t-Year Survivors With Censored Regression Models

Suppose that we are interested in establishing simple, but reliable rules for predicting future t-year survivors via censored regression models. In this article, we present inference procedures for evaluating such binary classification rules based on various prediction precision measures quantified by the overall misclassification rate, sensitivity and specificity, and positive and negative predictive values. Specifically, under various working models we derive consistent estimators for the above measures via substitution and cross validation estimation procedures. Furthermore, we provide large sample approximations to the distributions of these nonsmooth estimators without assuming that the working model is correctly specified. Confidence intervals, for example, for the difference of the precision measures between two competing rules can then be constructed. All the proposals are illustrated with two real examples and their finite sample properties are evaluated via a simulation study.

Mutual Information for Testing Gene-Environment Interaction

Despite current enthusiasm for investigation of gene-gene interactions and gene-environment interactions, the essential issue of how to define and detect gene-environment interactions remains unresolved. In this report, we define gene-environment interactions as a stochastic dependence in the context of the effects of the genetic and environmental risk factors on the cause of phenotypic variation among individuals. We use mutual information that is widely used in communication and complex system analysis to measure gene-environment interactions. We investigate how gene-environment interactions generate the large difference in the information measure of gene-environment interactions between the general population and a diseased population, which motives us to develop mutual information-based statistics for testing gene-environment interactions. We validated the null distribution and calculated the type 1 error rates for the mutual information-based statistics to test gene-environment interactions using extensive simulation studies. We found that the new test statistics were more powerful than the traditional logistic regression under several disease models. Finally, in order to further evaluate the performance of our new method, we applied the mutual information-based statistics to three real examples. Our results showed that P-values for the mutual information-based statistics were much smaller than that obtained by other approaches including logistic regression models.

An online e-Learning authoring tool to create interactive multi-device learning objects using e-Infrastructure resources

Education can take advantage of e-Infrastructures to provide teachers with new opportunities to increase students' motivation and engagement while they learn. Nevertheless, teachers need to find, integrate and customize the resources provided by e-Infrastructures in an easy way. This paper presents ViSH Editor, an innovative web-based e-Learning authoring tool that aims to allow teachers to create new learning objects using e-Infrastructure resources. These new learning objects are called Virtual Excursions and are created as reusable, granular and interoperable learning objects. This way they can be reused to build new ones and they can be integrated in websites or Learning Management Systems. Details about the design, development and the tool itself are explained in this paper as well as the concept, structure and metadata of the new learning objects. Lastly, some real examples of how to enrich learning using Virtual Excursions are exposed.

La competencia lingüística en el uso de los grupos nominales en inglés académico y profesional y su didáctica: estudio empírico

Esta tesis doctoral consiste en un estudio empírico de la competencia lingüística del alumnado de la Escuela Técnica Superior de Ingenieros Industriales (ETSII), de la Universidad Politécnica de Madrid (UPM) en el uso de los grupos nominales (GN) en inglés profesional y académico (IPA). Mediante el análisis estadístico de los datos de las pruebas de nivel de inglés general y de conocimiento de los rasgos lingüísticos diferenciadores del IPA, se ha buscado constatar que los GN, tan presentes en los textos ingleses de carácter científico-técnico, son uno de los rasgos IPA que más dificultad presenta para el alumnado de ingeniería de habla española, cuya enseñanza es necesario abordar de forma diferenciada para que se puedan usar correctamente. El trabajo comienza presentando las características lingüísticas generales del IPA, entre las que destaca la frecuente presencia de los GN en las comunicaciones de carácter científico y técnico. Comprueba la hipótesis de que la comprensión y el uso de los GN es el rasgo lingüístico que ofrece mayor dificultad para esta población. Se detiene en explicar las propiedades de los GN en inglés y de las palabras que lo forman; es decir, muestra clases de palabras, regularidades y excepciones que están presentes en los textos científico-técnicos. También expone y razona el comportamiento de las distintas categorías gramaticales que pueden figurar como premodificadoras y se centra en ejemplos reales y datos objetivos, para llegar a conclusiones cuantitativas sobre el uso y la frecuencia de los GN en el discurso científico-técnico, así como en los diferentes grados de dificultad que dichas construcciones presentan al alumnado. El método de investigación seguido consiste en la recopilación y análisis estadístico de los datos procedentes de una muestra de población de alumnos de 5º curso de la ETSII de la UPM utilizando el análisis de la varianza ANOVA. Los datos se han tratado teniendo en cuenta el nivel general de inglés de cada alumno, según el Marco Común Europeo de Referencia para las Lenguas (MCERL), que oscila entre el nivel A2 y el C1, con una mayor frecuencia de B1 y B2. Las conclusiones se basan en el análisis de los datos empíricos obtenidos, que nos permiten deducir unos principios generales relevantes respecto al uso de los GN –simples y complejos- en el inglés para la ciencia y la tecnología (ICT) y al grado de dificultad que sus distintos tipos presentan al alumnado, con un grado de confianza superior al 95%. A partir de estos datos se ofrece un planteamiento didáctico que facilite la comprensión y elaboración de los distintos tipos de GN. La estructura general de la tesis se divide en seis capítulos. El capítulo 1 es una introducción en la que se presentan las razones que han motivado esta tesis, las hipótesis, los objetivos y la metodología de la misma. En el capítulo 2 se recogen los rasgos lingüísticos distintivos del ICT, incidiendo en la relación competencia comunicativa/competencia lingüística. En el capítulo 3 se analizan los GN profundizando en aspectos lingüísticos. El capítulo 4 se centra en el estudio empírico propiamente dicho y en el análisis estadístico de los datos. Del análisis se extraen las conclusiones objetivas sobre la dificultad que presentan los diferentes rasgos IPA analizados, con detenimiento en los GN simples y complejos. El capítulo 5 ofrece un planteamiento didáctico práctico sobre la enseñanza de los GN en el contexto del ICT, con una investigación sobre el terreno y el análisis estadístico de los resultados obtenidos antes y después de la aplicación didáctica. En el capítulo 6 se comentan los resultados obtenidos a lo largo del estudio, aportando las conclusiones, las limitaciones y las recomendaciones para futuros trabajos de investigación sobre el tema de la tesis. ABSTRACT This doctoral thesis consists of an empirical study of the linguistic competence of the Technical University of Madrid (UPM) industrial engineering students on the use of nominal groups (NG) in English for Academic and Professional Purposes (EAPP). In order to confirm that NG is the EAPP linguistic feature that presents the greatest difficulty to Spanish engineering students, a statistical analysis of the data obtained from the application of a general English test and the EAPP linguistic features tests -developed for this purpose- was carried out. Consequently, this linguistic feature needs to be specifically taught in order to be used correctly by Spanish engineering students. The study begins by presenting the general language characteristics of EAPP, among which the frequent presence of NG in scientific and technical writings stands out. It verifies the hypothesis that the understanding and use of NG in English is the most difficult linguistic feature for Spanish engineering students. It explains the features of English NG analyzing the words they are composed of by depicting the types of words, regularities and exceptions that are present in technical and scientific English. It also explains the behavior of the different grammar categories that act as pre-modifiers of the noun and focuses on real examples taken from authentic publications and quantitative data, to reach objective conclusions about the use and degree of difficulty of the NG for the students. The research methodology includes the gathering of data from the 5th year industrial engineering students´ tests and analyzing them by means of the ANOVA statistical application. The data have been treated in relation to the students’ Common European Framework of Reference for Languages (CEFRL) levels, which range from A2 to C1, although the majority lye between B1 and B2 levels. The conclusions are based on the results, which allow us to obtain relevant information about the understanding and use of NG –simple and complex- by the focus group, with a 95% confidence level. From these data, a methodological approach to NG teaching has been tested to help students to acquire such linguistic feature. The general structure of this thesis is divided into six chapters. The first is an introduction containing the reasons that have motivated this piece of research, the hypotheses, objectives and methodology employed. The second deals with the distinctive linguistic features of EST underlying the concepts of linguistic and communicative competence. Chapter three focuses on the grammar aspects of NG. Chapter four contains the empirical study and the statistical analysis of the data. Results allow us to reach objective conclusions about the degree of difficulty of the EAPP linguistic features studied, focusing on simple and complex NG. Chapter five discusses a methodological approach to the teaching of NG in an EST context, comparing students’ test results before and after the NG teaching application. Finally, chapter six discusses the findings obtained along the study, presenting the conclusions, limitations and recommendations for future research in this area.

La escalera de caracol con ojo a finales del S.XV y comienzos del S.XVI: el caso de la ciudad y tierra de Segovia

Este trabajo de investigación se ha centrado en la escalera de caracol con ojo también denominado caracol de mallorca, en sus primeras apariciones a finales del s.XV y comienzos del s.XVI durante el llamado periodo tardogótico. Este elemento aparentemente sencillo presenta, sin embargo, una gran diversidad de esquemas geométricos. Todavía a día de hoy, no hay explicación del por qué de la mayor difusión de unos con respecto a otros. El objetivo de este trabajo ha sido valorar el papel que el confort/seguridad de uso así como la economía en el trabajo –sencillez de ejecución y coste económico– tuvieron en el contexto de la difusión de este elemento arquitectónico. Este estudio ha analizado en base a estos criterios objetivos, la geometría de cada uno de los esquemas tipo que resuelven la formación del hueco central característico este tipo de escaleras, con la intención de determinar las causas objetivas que pudieron motivar la desigual expansión de los mismos. Una vez determinado el marco teórico, se han establecido dos líneas para abordar el problema. Por un lado se ha planteado el análisis de los modelos teóricos recogidos en los distintos textos de cantería escritos por autores españoles desde finales del s.XVI. Si bien en la época en que se escribieron, la arquitectura gótica como sistema había desaparecido, alguno de sus elementos más característicos, como la escalera de caracol, continuaban empleándose. Las trazas del caracol con ojo recogidas en estos textos, describen habitualmente las soluciones geométricas más frecuentes e incluso los ejemplos construidos más conocidos, los cuales fueron levantados en su mayoría en el período en el cual se desarrolla esta investigación. Por otro lado, este estudio se plantea el análisis de modelos construidos existentes en la Ciudad y Tierra de Segovia. La razón que justifica dichos límites geográficos, la encontramos en que la mayor parte del patrimonio gótico existente en este área fue construido entre finales del s.XV y comienzos del s. XVI. Ambos grupos, modelos teóricos y modelos construidos, recogen la herencia gótica heredada en la construcción de este elemento arquitectónico. Cada una de estas dos líneas establecidas han seguido una metodología específica adaptada al objeto de análisis, si bien ambas se basan en un primer análisis individual y posterior análisis comparativo de los modelos seleccionados. Estos análisis han permitido identificar los distintos esquemas empleados para resolver el hueco central, lo que ha posibilitado establecer una clasificación general de los mismos en tres grupos: caracol con ojo de solución radial, el caracol con ojo de solución no radial y el caracol con ojo de solución tangencial. A partir de los datos y resultados obtenidos del análisis comparativo de los parámetros geométricos que afectan al confort/seguridad de uso y economía en el trabajo de dichos esquemas, podemos concluir que a pesar que los tres esquemas identificados resuelven el caracol con ojo de forma muy similar, el predominio de la solución radial y la caída en el olvido de las soluciones tangencial y no radial estuvieron justificados. ABSTRACT This work focused on the helical staircase, also known as mallorca staircase, in the late 15th and the early 16th centuries. This seemingly simple element, presents however a wide variety of geometrical designs. Still to date, there is no explanation of why some of them were limited use, while others had a wide impact. The aim of this study was to assess the influence which comfort, safety and work economy –ease of construction and financial cost– had on their widespread. This study analysed, following these objective criteria, the geometry of the different designs, which solve the characteristic inner aperture of this type of staircase. And thus, find the reasons, which motivated their uneven spread. Once the theoretical framework was developed, two research lines were set up to address the problem. On one hand, this study analysed the theoretical helical staircases described in the early Spanish texts, which were written since the end of the 16th century. Although these texts were written after the Gothic Architecture system had already disappeared, some of its more representative elements like the helical staircase were still in use. The traces of the helical stair, which are included in these texts, describe the most frequently-used designs and even the most famous real examples which were usually constructed in the Late Gothic period. On the other hand, this study analysed some real helical staircases, which were constructed in the Ciudad y Tierra de Segovia. The reason for choosing these geographical limits is that most of the Gothic buildings of this area were constructed between the end of the 15th and the early 16th centuries, during the Late Gothic period. Both groups, theoretical and constructed samples, collect the Gothic construction tradition of the helical stair. Each of these research lines followed a specific methodology, which was adapted to the research object. Nevertheless, both are based on a first individual analysis of each selected example and a later on comparative one. These analysis allowed the identification of the different layouts which solve the inner aperture of the helical staircase, what made possible to set up a broad classification in three groups, according to the geometrical design strategy that solves the central aperture: the helical staircase by radial solution, the helical staircase by non-radial solution and the helical staircase by tangent solution. The research findings of the comparative analysis of their geometrical parameters, which have an impact in the comfort, safety and work economy, have shown that although all of them solve the helical staircase in a really similar way, the fade into oblivion of the non-radial and tangent approaches was objectively motivated.

Genetic evidence for different male and female roles during cultural transitions in the British Isles

Human history is punctuated by periods of rapid cultural change. Although archeologists have developed a range of models to describe cultural transitions, in most real examples we do not know whether the processes involved the movement of people or the movement of culture only. With a series of relatively well defined cultural transitions, the British Isles present an ideal opportunity to assess the demographic context of cultural change. Important transitions after the first Paleolithic settlements include the Neolithic, the development of Iron Age cultures, and various historical invasions from continental Europe. Here we show that patterns of Y-chromosome variation indicate that the Neolithic and Iron Age transitions in the British Isles occurred without large-scale male movements. The more recent invasions from Scandinavia, on the other hand, appear to have left a significant paternal genetic legacy. In contrast, patterns of mtDNA and X-chromosome variation indicate that one or more of these pre-Anglo-Saxon cultural revolutions had a major effect on the maternal genetic heritage of the British Isles.

Humour in colloquial conversation

Researchers from the GRIALE group (Irony and Humour Research Group) have developed a theoretical method that can be applied to humorous ironic utterances in different textual genres, depending on the degree of the violation of conversational principles in conversation. In addition to this, the General Theory of Verbal Humor (Attardo and Raskin, 1991) will be taken into account in the analysis. Therefore, I will study irony and humour in conversational utterances in real examples of Peninsular Spanish obtained from the COVJA, (Corpus de conversaciones coloquiales [Corpus of Colloquial Conversations]) and CREA, (Corpus de Referencia del Español Actual [Reference Corpus of Present-Day Spanish]). The focus of this paper is then the application of the aforementioned theories to humorous ironic statements which arise in conversation. I will also examine the positive or negative effects caused by them, which will additionally verify if irony and humour coexist in the same conversational exchange, and if this has a communicative goal.

3D teaching: the ideal complement for professionals in design and construction

Today, the requirement of professional skills to university students is constantly increasing in our society. In our opinion, the content offered in official degrees need to be nourished with different variables, enriching their global professional knowledge in a parallel way; that is why, in recent years, there is a great multiplicity of complementary courses at university. One of the most socially demanded technical requirements within the architectural, design or engineering field is the management of 3D drawing software, becoming an indispensable reality in these sectors. Thus, this specific training becomes essential over two-dimension traditional design, because the inclusion of great possibilities of spatial development that go beyond conventional orthographic projections (plans, sections or elevations), allowing modelling and rotation of the selected items from multiple angles and perspectives. Therefore, this paper analyzes the teaching methodology of a complementary course for those technicians in the construction industry interested in computer-aided design, using modelling (SketchupMake) and rendering programs (Kerkythea). The course is developed from the technician point of view, by learning computer management and its application to professional development from a more general to a more specific view through practical examples. The proposed methodology is based on the development of real examples in different professional environments such as rehabilitation, new constructions, opening projects or architectural design. This multidisciplinary contribution improves criticism of students in different areas, encouraging new learning strategies and the independent development of three-dimensional solutions. Thus, the practical implementation of new situations, even suggested by the students themselves, ensures active participation, saving time during the design process and the increase of effectiveness when generating elements which may be represented, moved or virtually tested. In conclusion, this teaching-learning methodology improves the skills and competencies of students to face the growing professional demands of society. After finishing the course, technicians not only improved their expertise in the field of drawing but they also enhanced their capacity for spatial vision; both essential qualities in these sectors that can be applied to their professional development with great success.

How to survive your doctorate

If you are doing, thinking about doing, or know someone who is doing a doctorate, then this is the survival kit you need! Rather than focusing on the technical side of the doctorate, this book looks at all the other crucial skills that are part of everyday doctoral life. This candid book provides real insight into what it's like to do a doctorate and offers practical advice on: The application process, Sources of financial support, Motivational issues, Student-supervisor relationships, Departmental and university politics, Publishing, conferences and networking, Career strategies, Written by recent doctoral graduates, the book also includes real examples and case studies from current doctoral students and recent graduates across a range of disciplines and universities. By demystifying the doctoral process How to Survive Your Doctorate prepares you for life as a doctoral student like no other book. See for yourself and be a survivor!

Designing mobile technologies for individuals with disabilities

While mobile devices offer many innovative possibilities to help increase the standard of living for individuals with disabilities and other special needs, the process of developing assistive technology, such that it will be effective across a group of individuals with a particular disability, can be extremely challenging. This chapter discusses key issues and trends related to designing and evaluating mobile assistive technology for individuals with disabilities. Following an overview of general design process issues, we argue (based on current research trends) that individuals with disabilities and domain experts be involved throughout the development process. While this, in itself, presents its own set of challenges, many strategies have successfully been used to overcome the difficulties and maximize the contributions of users and experts alike. Guidelines based on these strategies are discussed and are illustrated with real examples from one of our active research projects.

Steps and bumps:precision extraction of discrete states of molecular machines

We report statistical time-series analysis tools providing improvements in the rapid, precision extraction of discrete state dynamics from time traces of experimental observations of molecular machines. By building physical knowledge and statistical innovations into analysis tools, we provide techniques for estimating discrete state transitions buried in highly correlated molecular noise. We demonstrate the effectiveness of our approach on simulated and real examples of steplike rotation of the bacterial flagellar motor and the F1-ATPase enzyme. We show that our method can clearly identify molecular steps, periodicities and cascaded processes that are too weak for existing algorithms to detect, and can do so much faster than existing algorithms. Our techniques represent a step in the direction toward automated analysis of high-sample-rate, molecular-machine dynamics. Modular, open-source software that implements these techniques is provided.

Analysis of constructivist, network-based discourses:concepts, prospects, and illustrations

The authors propose a new approach to discourse analysis which is based on meta data from social networking behavior of learners who are submerged in a socially constructivist e-learning environment. It is shown that traditional data modeling techniques can be combined with social network analysis - an approach that promises to yield new insights into the largely uncharted domain of network-based discourse analysis. The chapter is treated as a non-technical introduction and is illustrated with real examples, visual representations, and empirical findings. Within the setting of a constructivist statistics course, the chapter provides an illustration of what network-based discourse analysis is about (mainly from a methodological point of view), how it is implemented in practice, and why it is relevant for researchers and educators.

Designing mobile technologies for individuals with disabilities

While mobile devices offer many innovative possibilities to help increase the standard of living for individuals with disabilities and other special needs, the process of developing assistive technology, such that it will be effective across a group of individuals with a particular disability, can be extremely challenging. This chapter discusses key issues and trends related to designing and evaluating mobile assistive technology for individuals with disabilities. Following an overview of general design process issues, we argue (based on current research trends) that individuals with disabilities and domain experts be involved throughout the development process. While this, in itself, presents its own set of challenges, many strategies have successfully been used to overcome the difficulties and maximize the contributions of users and experts alike. Guidelines based on these strategies are discussed and are illustrated with real examples from one of our active research projects.

Mixtures of g-priors in Generalized Linear Models

Mixtures of Zellner's g-priors have been studied extensively in linear models and have been shown to have numerous desirable properties for Bayesian variable selection and model averaging. Several extensions of g-priors to Generalized Linear Models (GLMs) have been proposed in the literature; however, the choice of prior distribution of g and resulting properties for inference have received considerably less attention. In this paper, we extend mixtures of g-priors to GLMs by assigning the truncated Compound Confluent Hypergeometric (tCCH) distribution to 1/(1+g) and illustrate how this prior distribution encompasses several special cases of mixtures of g-priors in the literature, such as the Hyper-g, truncated Gamma, Beta-prime, and the Robust prior. Under an integrated Laplace approximation to the likelihood, the posterior distribution of 1/(1+g) is in turn a tCCH distribution, and approximate marginal likelihoods are thus available analytically. We discuss the local geometric properties of the g-prior in GLMs and show that specific choices of the hyper-parameters satisfy the various desiderata for model selection proposed by Bayarri et al, such as asymptotic model selection consistency, information consistency, intrinsic consistency, and measurement invariance. We also illustrate inference using these priors and contrast them to others in the literature via simulation and real examples.