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  • Estimation of survival functions subject to order restrictions

     Serrat Pie, Carles; Moreno, Laura
    ICSO-HAROSA International Workshop on Simulation-Optimization & Internet Computing
    Presentation's date: 2013-07-10
    Presentation of work at congresses

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    This contribution is framed in, and is part of, the Durabiltiy of Building Facades studies carried out in the last decade in the Institut d¿Estadística i Matemàtica Aplicada a l¿Edificació and Laboratori d¿ Edificació at the Universitat Politècnica de Catalunya. The goal of this presentation is to incorporate in the analysis of the estimation of the durability of building facades respect the severity degrees (low, medium or high) the order of the events of interest. In other words, we will take into account preliminary estimates of the survival probabilities of previous events (e.g. initial severities) as order constraints for the estimation of survival probabilities for subsequent events of interest (e.g. more advanced severities). Standard statistical analyses for this type of interval censored data are usually conducted by using the R statistical software, however it does not include libraries or packages neither for simultaneous estimation nor for the use of order constraints. For this reason, we will use AMPL and the solver SNOPT to implement the Turnbull's estimator with order restrictions, for the estimation of the survival function of each event of interest taking into account the information given by the survival function of some previous event of interest. The proposed methodology solves the inconsistency problem associated with a separate estimation of the respective survival probabilities. As a illustration the methodology will be applied to a simulated dataset. As a theoretical contribution, a conjecture on Turnbull's estimator Theorem under order restrictions will be proposed.

  • Joint modelling analysis of prostate cancer incidence: frequentist and bayesian approaches

     Piulachs, Xavier; Serrat Pie, Carles; Rué, Montserrat; Armero, Carmen; Forte, Anabel; Perpiñán, Héctor; Luján, Marcos; Páez, Álvaro
    Conferencia Española de Biometría
    Presentation's date: 2013-05-24
    Presentation of work at congresses

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    Prostate specific antigen (PSA) is a biomarker for prostate cancer (PCa) that is widely used for PCa screening. Using a database of 2415 men included in the Spanish screening arm of the ERSPC Study, we will use joint modelling strategies to analyze if longitudinal PSA profiles and time to PCa incidence allow to obtain a better estimate of the individual risk of PCa. Conclusions and limitations of the study will be discussed.

  • Longitudinal + reliability = joint modeling

     Serrat Pie, Carles
    International Workshop on Simulation-Optimization for Logistics & Production
    Presentation's date: 2013-11-21
    Presentation of work at congresses

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    The aim of this presentation is to introduce joint modelling techniques for the simultaneous analysis of longitudinal time-varying data and time-to-event data. This is an increasing area of interest for the analysis of complex systems. Among others, three main advantages of this approach are: a) it corrects the bias derived from a traditional separate analysis, b) the modelization allows to incorporate and model the between and within correlation among observations and, c) true longitudinal profiles for endogenous covariates can be included in the relative hazard survival sub-model. The relevant benefit of these models is being able to estimate the effect of each subject-specific longitudinal profile in the hazard function for the event of interest, in an adaptive manner. In particular, subject-specific dynamic predictions, like conditional survival functions given the available longitudinal information, can be derived. In order to implement joint models, existing open source libraries in R will be introduced and some illustrations will be given.

  • A semi-parametric joint model for two sequential times to events and one longitudinal covariate

     Serrat Pie, Carles; Abel Huertas, Jaime; Gomez Melis, Guadalupe
    International Workshop on Statistical Modelling
    Presentation's date: 2012-07-16
    Presentation of work at congresses

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    On the design of a survey to measure effective communication in building  Open access

     Serrat Pie, Carles; Rodriguez, Sonia; Forcada Matheu, Nuria
    International Scientific Conference People, Buildings and Environment
    Presentation's date: 2012-11
    Presentation of work at congresses

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    Although effective communication is identified as a key indicator of project performan ce, communication aspects on contractors’ evaluation are not yet included. This paper aims to review the most relevant contributions on the specific literature in order to design a survey to test for the parameters that affect effective communication among Construction Agents (CA), i.e. PM’s, builder, designer and other professionals participants, during the construction process of the project. The survey will be based on the experience and perceptions of the corresponding professionals in Spain. The availa bility of these par ameters is crucial and it represents basic information for developing procedures and tools for the evaluation and selection management of CAs.

  • On the design of a survey to measure effective communication in building

     Serrat Pie, Carles; Rodriguez, Sonia; Forcada Matheu, Nuria
    International Scientific Conference People, Buildings and Environment
    Date of publication: 2012-11
    Journal article

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  • Computational tools for joint modelling time to event and longitudinal data

     Huertas, J.; Serrat Pie, Carles; Gomez Melis, Guadalupe
    Date: 2012-04-24
    Report

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  • Joint modelling of two sequential times to event with longitudinal information

     Huertas, Jaime-Abel; Gomez Melis, Guadalupe; Serrat Pie, Carles
    International Workshop on Statistical Modelling
    Presentation's date: 2011-07-14
    Presentation of work at congresses

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    Survival analysis methodology for service live prediction and building maintenance  Open access

     Serrat Pie, Carles; Gibert Armengol, Vicente
    International Conference on Durability of Building Materials and Components
    Presentation's date: 2011-04-15
    Presentation of work at congresses

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    This paper deals with, on one hand, the introduction of survival analysis techniques for being used in building maintenance and, on the other hand, the application of this methodology for analyzing a large building stock in order to obtain information for maintenance strategies and/or prevention policies. In particular, in this contribution the description of the time to the event when the event of interest is some damage (or some level of degradation or extent) on the building façade is the main goal to reach. For the time being, building follow-up is based on inspections. However, data coming from building inspections are always not completed, but censored, due to the fact that, at each inspection time, the event of interest is already happened, or not yet. In order to solve this problematic, the existing methodology for fields like medicine, biology, industrial engineering or event history analysis is adapted, and routines in S-PLUS for a numerical and graphical systematic analysis are implemented. Estimates for non-parametric durability and hazard functions are derived. The possibilities of the proposed methodology will be illustrated with its application to the building façades in Hospitalet de Llobregat, the second most important city in population in Catalonia (Spain), where more than 14.000 buildings have been inspected. The analysis of the results allows technicians to detect different zones and levels of intervention to be applied in the city.

  • Joint Modelling of Two Sequential Times to Event with Longitudinal Information

     Huertas Campos, Jaime Abel
    Defense's date: 2011-11-03
    Department of Statistics and Operations Research, Universitat Politècnica de Catalunya
    Theses

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  • Is one inspection enough to estimate durability in buildings?a simulation study

     Serrat Pie, Carles
    International Scientific Conference People, Buildings and Environment
    Presentation's date: 2010-11-11
    Presentation of work at congresses

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  • Técnicas de análisis de supervivencia aplicadas a la conservación del patrimonio construido

     Gibert Armengol, Vicente; Serrat Pie, Carles; Royano García, Verónica
    Congreso Internacional de Rehabilitación del Patrimonio Arquitectónico y Edificación
    Presentation's date: 2010-11-04
    Presentation of work at congresses

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  • ¿Cuán a menudo hay que inspeccionar el patrimonio edificado? Respuesta a partir de un estudio de simulación en durabilidad

     Serrat Pie, Carles
    Congreso Internacional de Rehabilitación del Patrimonio Arquitectónico y Edificación
    Presentation's date: 2010-11-04
    Presentation of work at congresses

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  • Potential applications of discrete-event simulation and fuzzy rule-based systems to structural reliability and availability

     Juan Perez, Angel Alejandro; Ferrer Biosca, Alberto; Serrat Pie, Carles; Faulín, Javier; Beliakov, Gleb; Hester, J.
    Date of publication: 2010
    Book chapter

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    This chapter discusses and illustrates some potential applications of discrete-event simulation (DES) techniques in structural reliability and availability analysis, emphasizing the convenience of using probabilistic approaches in modern building and civil engineering practices. After reviewing existing literature on the topic, some advantages of probabilistic techniques over analytical ones are highlighted. Then, we introduce a general framework for performing structural reliability and availability analysis through DES. Our methodology proposes the use of statistical distributions and techniques ¿ such as survival analysis ¿ to model component-level reliability. Then, using failure- and repair-time distributions and information about the structural logical topology (which allows determination of the structural state from their components¿ state), structural reliability, and availability information can be inferred. Two numerical examples illustrate some potential applications of the proposed methodology to achieving more reliable and structural designs. Finally, an alternative approach to model uncertainty at component level is also introduced as ongoing work. This new approach is based on the use of fuzzy rule-based systems and it allows the introduction of experts¿ opinions and evaluations in our methodology.

  • Interval-Censored Semi-Competing Risks Data: a Novel Approach for Modelling Bladder Cancer  Open access

     Porta Bleda, Nuria
    Defense's date: 2010-07-27
    Department of Statistics and Operations Research, Universitat Politècnica de Catalunya
    Theses

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    Aquesta tesi tracta sobre tècniques d'anàlisi de supervivència en situacions amb múltiples esdeveniments i patrons complexes de censura. Proposem una nova metodologia per tractar la situació de riscos semi-competitius quan les dades estan censurades en un interval. La motivació del treball neix de la nostra col·laboració amb l'Estudi Espanyol del Càncer de Bufeta (SBC/EPICURO), el més gran estudi sobre càncer de bufeta realitzat fins ara a l'Estat Espanyol. La nostra contribució en el projecte es centra en la modelització i identificació de factors pronòstics de l'evolució de la malaltia.L'evolució de malalties complexes, com el càncer o la infecció VIH, es caracteritza per la ocurrència de múltiples esdeveniments en el mateix pacient: per exemple, la recaiguda de la malaltia o la mort. Aquests esdeveniments poden ser finals, quan el seguiment del pacient s'atura després de l'esdeveniment, o bé intermedis, quan l'individu continua sota observació. La presència d'esdeveniments finals complica l'anàlisi dels intermedis ja que n'impedeix la seva completa observació, induint una possible censura depenent.En aquest context, es requereixen metodologies apropiades. Els següents mètodes són emprats: riscos competitius, models multiestat i riscos semi-competitius. A resultes de l'aplicació de mètodes per riscos competitius i models multi-estat, proposem dues aportacions rellevants al coneixement de la malaltia: (1) la caracterització dels pacients amb un alt risc de progressió com a primer esdeveniment després de la diagnosi, i (2) la construcció d'un model pronòstic dinàmic per al risc de progressió.La situació de riscos competitius es dóna quan volem descriure el temps fins al primer entre K possibles esdeveniments, juntament amb un indicador del tipus d'esdeveniment observat. En l'estudi EPICURO, és rellevant estudiar el temps fins al primer entre recidiva, progressió o mort. La caracterització d'aquest primer esdeveniment permetria seleccionar el millor tractament d'acord amb el perfil de risc basal del pacient.Els models multi-estat descriuen les diferents evolucions que la malaltia pot seguir, establint relacions entre els esdeveniments d'interès: per exemple, un pacient pot experimentar una recidiva del tumor primari, i després morir, o bé pot morir sense haver tingut cap recaiguda de la malaltia. Una característica interessant d'aquests models és que permeten fer prediccions del risc de futurs esdeveniments per a un pacient, d'acord amb la història que hagi pogut tenir fins aquell moment. En el cas de càncer de bufeta podrem avaluar la influència que té en el risc de progressar haver patit o no una recidiva prèvia.Un cas especial de model multi-estat és aquell que conté un esdeveniment intermedi E1, i un esdeveniment final, E2. Siguin T1 i T2 els temps fins aquests esdeveniments, respectivament. Ni l'anàlisi de riscos competitius ni els models multi-estat permeten adreçar l'estudi de la distribució marginal de T1. En efecte, l'anàlisi de riscos competitius tracta amb la distribució del mínim entre els dostemps, T=min(T1,T2), mentre que els models multi-estat es centren en la distribució condicional de T2|T1, és a dir, en com la ocurrència de E1 modifica el risc de E2. En aquest cas, la distribució de T1 no és identificable a partir de les dades observades. La situació abans descrita, on la ocurrència d'un esdeveniment final impedeix l'observació de l'esdeveniment intermedi és coneguda com a riscos semi-competitius (Fine et al., 2001). L'estratègia d'aquests autors passà per assumir un model per a la distribució conjunta (T1, T2), i aleshores recuperar la distribució marginal de T1 derivada d'aquest model.Proposem una nova metodologia per tractar amb riscos semi-competitius quan el temps fins l'esdeveniment intermedi, T1, està censurat en un interval. En molts estudis mèdics longitudinals, la ocurrència de l'esdeveniment d'interès s'avalua en visites periòdiques del pacient, i per tant, T1 és desconegut, però es sap que pertany al interval comprès entre els temps de dues visites consecutives. Els mètodes per riscos semi-competitius en el context usual de censura per la dreta no són vàlids en aquest cas i és necessària una nova aproximació. En aquest treball ampliem la metodología semi-paramètrica proposada per Fine et al. (2001), que assumeix un model de còpula de Clayton (1978) per a descriure la dependència entre T1 i T2. Assumint el mateix model, desenvolupem un algoritme iteratiu que estima conjuntament el paràmetre d'associació del model de còpula, així com la funció de supervivència del temps intermedi T1.Fine, J. P.; Jiang, H. & Chappell, R. (2001), 'On Semi-Competing Risks Data', Biometrika 88(4), 907--919.Clayton, D. G. (1978), 'A Model for Association in Bivariate Life Tables and Its Application in Epidemiological Studies of Familial. Tendency in Chronic Disease Incidence', Biometrika 65(1), 141--151.

    La presente tesis trata sobre técnicas de análisis de supervivencia en situaciones con múltiples eventos y patrones complejos de censura. Proponemos una nueva metodología para tratar el problema de riesgos semi-competitivos cuando los datos están censurados en un intervalo. La motivación de este trabajo nace de nuestra colaboración con el estudio Español de Cáncer de Vejiga (SBC/EPICURO), el más grande estudio sobre cáncer de vejiga realizado en España hasta el momento. Nuestra participación en el mismo se centra en la modelización e identificación de factores pronósticos en el curso de la enfermedad.El curso de enfermedades complejas tales como el cáncer o la infección por VIH, se caracteriza por la ocurrencia de múltiples eventos en el mismo paciente, como por ejemplo la recaída o la muerte. Estos eventos pueden ser finales, cuando el seguimiento del paciente termina con el evento, o bien intermedios, cuando el individuo sigue bajo observación. La presencia de eventos finales complica el análisis de los eventos intermedios, ya que impiden su completa observación, induciendo una posible censura dependiente.En este contexto, se requieren metodologías apropiadas. Se utilizan los siguientes métodos: riesgos competitivos, modelos multiestado y riesgos semi-competitivos. De la aplicación de métodos para riesgos competitivos y modelos multi-estado resultan dos aportaciones relevantes sobre el conocimiento de la enfermedad: (1) la caracterización de los pacientes con un alto riesgo de progresión como primer evento después del diagnóstico, y (2) la construcción de un modelo pronóstico y dinámico para el riesgo de progresión.El problema de riesgos competitivos aparece cuando queremos describir el tiempo hasta el primero de K posibles eventos, junto con un indicador del tipo de evento observado. En el estudio SBC/EPICURO es relevante estudiar el tiempo hasta el primero entre recidiva, progresión o muerte. La caracterización de este primer evento permitiría seleccionar el tratamiento más adecuado de acuerdo con el perfil de riesgo basal del paciente.Los modelos multi-estado describen las diferentes tipologías que el curso de la enfermedad puede seguir, estableciendo relaciones entre los eventos de interés. Por ejemplo, un paciente puede experimentar una recidiva y después morir, o bien puede morir sin haber tenido recaída alguna. El potencial interesante de los modelos multi-estado es que permiten realizar predicciones sobre el riesgo de futuros eventos dada la historia del paciente hasta ese momento. En el caso del cáncer de vejiga, podremos evaluar la influencia que tiene en el riesgo de progresar el haber tenido o no una recidiva previa.Un caso especial de modelo multi-estado es el que contiene un evento intermedio E1 y uno final, E2. Sean T1 y T2 los tiempos hasta tales eventos, respectivamente. Ni el análisis de riesgos competitivos ni los modelos multi-estado permiten estudiar la distribución marginal de T1. En efecto, el análisis de riesgos competitivos trata con la distribución del mínimo entre los dos tiempos, T=min(T1,T2), mientras que los modelos multi-estado se centran en la distribución condicional de T2 dado T1, T2|T1, en cómo la ocurrencia de E1 modifica el riesgo de E2. En ambos casos, la distribución de T1 no es identificable a partir de los datos observados.La situación anteriormente descrita donde un evento final impide la observación de un evento intermedio se conoce como riesgos semi-competitivos (Fine et al. 2001). La estrategia de estos autores asume un modelo para la distribución conjunta (T1,T2) para así recuperar la distribución de T1 derivada de ese modelo.Proponemos una nueva metodología para tratar con riesgos semi-competitivos cuando el tiempo hasta el evento intermedio, T1, esta censurado en un intervalo. En muchos estudios médicos longitudinales, la ocurrencia del evento de interés se evalúa en visitas periódicas al paciente, por lo que T1 es desconocido, aunque se conoce que pertenece al intervalo comprendido entre los tiempos de dos visitas consecutivas. Los métodos para riesgos semi-competitivos en el contexto usual de censura por la derecha no son válidos en este caso y se requiere una nueva aproximación. En este trabajo ampliamos la metodología semi-paramétrica propuesta por Fine et al. (2001), que asume una cópula de Clayton (1978) para describir la dependencia entre T1 y T2. Bajo el mismo modelo de asociación, desarrollamos un algoritmo iterativo que estima conjuntamente el parámetro de asociación del modelo de cópula, así como la función de supervivencia del tiempo al evento intermedio T1.Fine, J. P.; Jiang, H. & Chappell, R. (2001), 'On Semi-Competing Risks Data', Biometrika 88(4), 907--919. Clayton, D. G. (1978), 'A Model for Association in Bivariate Life Tables and Its Application in Epidemiological Studies of Familial. Tendency in Chronic Disease Incidence', Biometrika 65(1), 141--151.

  • Álgebra

     Huertas Sanchez, Maria Antonia; Serrat Pie, Carles; Fortuny Anguera, Gerard; García López, Alfonsa; Juan Perez, Angel Alejandro; Parés Mariné, Núria; Pozo Montero, Francesc; Steegmann Pascual, Cristina; Vidal Segui, Yolanda; Lapedriza Garcia, Àgata
    Date of publication: 2010
    Book

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  • Àlgebra

     Huertas Sanchez, Maria Antonia; Lapedriza, A.; Serrat Pie, Carles
    Date of publication: 2010
    Book

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  • Using discrete-event simulation to design reliable and cost-efficient civil engineering structures

     Ferrer Biosca, Alberto; Serrat Pie, Carles; Faulín, Javier; Hester, Josh; Juan Pérez, Ángel Alejandro; López Brosa, Pere
    Date of publication: 2009
    Book chapter

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    In this paper the topic of Structural Reliability Analysis and its importance in modern Civil Engineering is introduced. Throughout the paper, some advantages that simulation-based approaches offer with respect to other classical approaches are discussed. After a review of the most relevant literature on the subject, a simulation-based approach is described. Our methodology makes use of discrete-event simulation techniques to help the civil engineer design more reliable and cost-efficient structures. A numerical example illustrates some potential applications of the proposed methodology. Finally, potential research and academic applications of this approach are also discussed.

  • Applications of discrete-event simulation to reliability and availability assessment in civil engineering structures

     Juan-Pérez, Angel A.; Monteforte, Arai; Ferrer Biosca, Alberto; Serrat Pie, Carles; Faulín, Javier
    Date of publication: 2009
    Book chapter

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    Welcome to the 2009 Winter Simulation Conference (WSC), recognized as the premiere international conference for simulation professionals in discrete and combined discrete-continuous simulation. WSC is always located in exciting and dynamic locations and in 2009 we are delighted to hold the conference in Austin, Texas. This is the first time that WSC has been held in Texas. The conference theme, Energy Alternatives, encourages attendees to examine the issues of energy supply, technology development and deployment, and climate change and invites practitioners to share their contributions to solving these pressing global challenges through the use of modeling and simulation. These efforts are highlighted in the new Energy and Material Flow Simulation track. WSC '09 offers a comprehensive program ranging from introductory tutorials to state-of-the-art research and practice. Following its unbridled success last year, WSC '09 will again incorporate the MASM (Modeling and Analysis for Semiconductor Manufacturing) Conference, the leading modeling and analysis conference for global semiconductor manufacturing and supply chain operations. WSC '09 also continues the popular pre-conference workshop Simulation 101 and expands the training offerings with a full week of training sessions running in parallel to the main conference tracks.

  • Access to the full text
    The use of survival analysis techniques in building maintenance  Open access

     Serrat Pie, Carles
    International Scientific Conference People, Buildings and Environment
    Presentation's date: 2009-11
    Presentation of work at congresses

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    We want, on one hand, to introduce survival analysis techniques for being used in building maintenance and, on the other hand, to apply this methodology for analyzing a large building stock in order to obtain information for maintenance strategies and/or prevention policies. For the time being, building follow-up is based on inspections. Data coming from building inspections are always censored, due to the fact that, at each inspection time, the event of interest is already happened, or not yet. After the analysis of this type of data, durability and hazard functions are derived. The possibilities of this proposal will be illustrated with the analysis of all the buildings façades in Hospitalet de Llobregat, the second most important city in population in Catalonia (Spain).

    Postprint (author’s final draft)

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    IEMAE: mathematics & statistics applied to civil engineering & building  Open access

     Serrat Pie, Carles
    HAROSA Workshop: Hybrid Algorithms for solving Realistic Routing, Scheduling and Reliability/Availability problems
    Presentation's date: 2009-11
    Presentation of work at congresses

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    IEMAE (Institut d’Estadística i Matemàtica Aplicada a l’Edificació - Institute of Statistics and Mathematics Applied to the Building Construction) is an academic institution interested in solving Multidisciplinary problems in the civil and building engineering area by using statistics and mathematics disciplines

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    Applications of discrete-event simulation to reliability and availability assesment in civil engineering structures  Open access

     Ferrer Biosca, Alberto; Serrat Pie, Carles; Faulín, Javier; Juan-Pérez, Angel A.; Monteforte, Arai
    Winter Simulation Conference
    Presentation's date: 2009
    Presentation of work at congresses

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    This paper discusses the convenience of predicting, quantitatively, time-dependent reliability and availability levels asso-ciated with most building or civil engineering structures. Then, the paper reviews different approaches to these problems and proposes the use of discrete-event simulation as the most realistic way to deal with them, specially during the design stage. The paper also reviews previous work on the use of both Monte Carlo simulation and discrete-event simulation in this area and shows how discrete-event simulation, in particular, could be employed to solve uncertainty in time-dependent structural reliability problems. Finally, a case study is developed to illustrate some of the concepts previously covered in the paper.

  • Access to the full text
    Using discrete-event simulation to design reliable and cost-efficient civil engineering structures  Open access

     Juan Perez, Angel Alejandro; Ferrer Biosca, Alberto; Serrat Pie, Carles; Faulín, Javier; Lopez Brosa, Pere; Hester, Josh
    European Modeling and Simulation Symposium
    Presentation's date: 2009
    Presentation of work at congresses

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    In this paper the topic of Structural Reliability Analysis and its importance in modern Civil Engineering is introduced. Throughout the paper, some advantages that simulation-based approaches offer with respect to other classical approaches are discussed. After a review of the most relevant literature on the subject, a simulation-based approach is described. Our methodology makes use of discrete-event simulation techniques to help the civil engineer design more reliable and cost-efficient structures. A numerical example illustrates some potential applications of the proposed methodology. Finally, potential research and academic applications of this approach are also discussed.

    In this paper the topic of Structural Reliability Analysis and its importance in modern Civil Engineering is introduced. Throughout the paper, some advantages that simulation-based approaches offer with respect to other classical approaches are discussed. After a review of the most relevant literature on the subject, a simulation-based approach is described. Our methodology makes use of discrete-event simulation techniques to help the civil engineer design more reliable and cost-efficient structures. A numerical example illustrates some potential applications of the proposed methodology. Finally, potential research and academic applications of this approach are also discussed.

  • Discrete event simulation and fuzzy sets in structural reliability and availability in building construction

     Ferrer Biosca, Alberto; Juan Perez, Angel Alejandro; Serrat Pie, Carles; Lopez, P.; Faulín, Javier; Beliakov, Gleb
    International Conference on Construction and Building Research
    Presentation's date: 2009-06-24
    Presentation of work at congresses

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  • Survival analysis techniques applied to building maintenance

     Serrat Pie, Carles; Gibert Armengol, Vicente; Jordana Riba, Francisco de Paula
    International Conference on Construction and Building Research
    Presentation's date: 2009-06-24
    Presentation of work at congresses

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    This paper has two main objectives: On the one hand, we want to introduce survival analysis techniques for use in building maintenance and, on the other hand, to apply this methodology to analyzing a large building stock in order to obtain information for maintenance strategies and/or prevention policies. Similar to technical systems, buildings and their elements are also subject to aging. They age even faster when they are exposed to external (sometimes extreme) weather conditions. In this paper we are particularly interested in describing the time to the event when the event of interest is some damage (or level of degradation) on the building façade which can represent some risk for people (inside or outside the building). For the time being, building follow-up is based on inspections. Data coming from building inspections is always inaccurate, but censored, due to the fact that, at each inspection time, the event of interest has already happened, or not yet happened. We have adapted the existing methodology for fields like medicine, biology, industrial engineering or event history analysis, and we have implemented in S-PLUS®, by Insightful®, the routines for a numerical and graphical systematic analysis. The potential of this proposal is illustrated with its application to a real dataset. We have been collecting data for years from all the buildings façades in Hospitalet de Llobregat, the second most populous city in Catalonia (Spain). More than 10,000 buildings have been inspected and an exhaustive checklist has been completed for each one. The analysis of the results allows technicians to detect different zones and levels of intervention to be applied in the city

  • ANALISIS DE SUPERVIVENCIA PARA MULTIPLES EVENTOS CON PATRONES DE CENSURA COMPLEJOS

     Serrat Pie, Carles; Langohr, Klaus; Perez Alvarez, Nuria; Porta Bleda, Nuria; Gomez Melis, Guadalupe
    Participation in a competitive project

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  • Predicting availability functions in time-dependent complex systems with SAEDES simulation algorithms

     Faulín, Javier; Juan Perez, Angel Alejandro; Serrat Pie, Carles; Bargueño, Vicente
    Reliability engineering and system safety
    Date of publication: 2008-11
    Journal article

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  • Mathematical e-Learning: state of the art and experiences at the Open University of Catalonia

     Juan Perez, Angel Alejandro; Huerta Cerezuela, Antonio; Steegmann, C; Corcoles, C; Serrat Pie, Carles
    International journal of mathematical education in science and technology (Print)
    Date of publication: 2008-01
    Journal article

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  • A simulation-based algorithm to predict time-dependent structural reability

     Juan Perez, Angel Alejandro; Serrat Pie, Carles; Ferrer Biosca, Alberto; Faulín, Javier; Sorroche Montellano, Mateo
    Date of publication: 2008
    Book chapter

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  • Nonparametric bivariate estimation for successive survival times

     Serrat Pie, Carles; Gomez Melis, Guadalupe
    SORT: statistics and operations research transactions
    Date of publication: 2007-01
    Journal article

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  • Joint modelling of a longitudinal variable and a time to event data: methodological and computational issues

     Serrat Pie, Carles; Huertas, J A; Gomez Melis, Guadalupe
    22 International Workshop on Statistical Modelling (IWSM'2007)
    Presentation of work at congresses

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  • Using simulation to determine reliability and availability of telecommunication networks

     Faulín, Javier; Juan Perez, Angel Alejandro; Serrat Pie, Carles; Bargueno, Vicente
    European journal of industrial engineering
    Date of publication: 2007-01
    Journal article

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  • Number of consumers necessary for shelf life estimations based on survival analysis statistics

     Hough ., Guillermo; Calle Rosingana, M. Luz; Serrat Pie, Carles; Curia, Ana
    Food quality and preference
    Date of publication: 2007-07
    Journal article

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  • Designing Reliable Systems and Networks using Discrete-Event Simulation: a case study

     Juan Perez, Angel Alejandro; Faulín, Javier; Serrat Pie, Carles; Marqués, J.
    International Mediterranean Modelling Multiconference
    Presentation of work at congresses

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  • An IPCW estimator for ordered failure times subject to a common censoring process

     Serrat Pie, Carles
    XXIIIrd International Biometric Conference
    Presentation's date: 2006-07-21
    Presentation of work at congresses

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  • Àlgebra

    Date of publication: 2006-12-31
    Book

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  • Álgebra

    Date of publication: 2006-12-31
    Book

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  • REMIC: recerca en educació matemàtica i científica

     Serrat Pie, Carles; Pintó Casulleras, Roser
    Participation in a competitive project

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  • Determination of optimum concentrations of a food ingredient using survival analysis statistics

     Garitta, Lorena V.; Serrat Pie, Carles; Hough ., Guillermo; Curia, Ana
    Journal of food science
    Date of publication: 2006-09
    Journal article

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  • Estadística Industrial

     Serrat Pie, Carles; Juan Perez, Angel Alejandro
    Date of publication: 2005-12
    Book

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  • Matemáticas i

    Date of publication: 2005-12-31
    Book

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  • Algebra

    Date of publication: 2005-12-01
    Book

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  • Estadística española

     Serrat Pie, Carles
    Collaboration in journals

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  • SAEDES++: determining complex system availability via simulation

     Juan Perez, Angel Alejandro; Faulín, Javier; Bargueño, Vicente; Serrat Pie, Carles
    Winter Simulation Conference
    Presentation of work at congresses

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  • Matemàtiques i

    Date of publication: 2005-12-01
    Book

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  • Àlgebra

    Date of publication: 2005-12-31
    Book

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  • Matemáticas I

     Huertas Sanchez, Maria Antonia; Juan Perez, Angel Alejandro
    Date of publication: 2005-12
    Book

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  • Estadística de supervivencia aplicada a la vida útil sensorial de alimentos: tutorial introductorio y cálculos a realizar utilizando S-PLUS

     Garitta, Lorena V.; Gomez Melis, Guadalupe; Hough ., Guillermo; Langohr, Klaus; Serrat Pie, Carles
    Date of publication: 2004-10
    Book

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  • Review of multivariate survival data

     Gomez Melis, Guadalupe; Calle Rosingana, M. Luz; Espinal Berenguer, Anna; Serrat Pie, Carles
    Date: 2004-09
    Report

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    This paper reviews some of the main contributions in the area of multivariate survival data and proposes some possible extensions. In particular, we have concentrated our search and study on those papers that are relevant to the situation where two (or more) consecutive variables are followed until a common day of analysis and subject to informative censoring. The paper reviews bivariate nonparametric approaches and extend some of them to the case of two nonconsecutive times. We introduce the notation and construct the likelihood for the general problem of more than two consecutive survival times. We formulate the time dependencies and trends via a Bayesian approach. Finally, three regression models for multivariate survival times are discussed together with the differences among them which will be useful when the main interest is on the effect of covariates on the risk of failure.