Ponències/Comunicacions de congressos
http://hdl.handle.net/2117/3920
Thu, 23 Mar 2017 22:28:35 GMT2017-03-23T22:28:35ZMultidimensional big data processing for damage detection in real pipelines using a smart pig tool
http://hdl.handle.net/2117/102797
Multidimensional big data processing for damage detection in real pipelines using a smart pig tool
Ruiz Ordóñez, Magda; Mujica Delgado, Luis Eduardo; Alférez Baquero, Edwin Santiago; Quintero, Mario; Villamizar Mejía, Rodolfo
The history of the hydrocarbons business in Colombia dates back to the early twentieth century where mining and energy sector has been one of the principal pillars for the its development. Thus, the pipelines currently in service have over 30 years and most of them are buried and phenomena like metal losses, corrosion, mechanical stress, strike by excavation machinery and other type of damages are presented. Since it can generate social and environmental problems, monitoring tools and programs should be developed in order to prevent catastrophic situations. However, the maintaining of these structures is very expensive and it is normally developed by foreign companies. In order to overcome this situation, recently the native research institute “Research Institute of Corrosion - CIC (Corporación para la Investigación de la Corrosión)” developed an in-line inspection tool to be operated in Colombian pipelines (especially gas) to get valuable information of their current state along of thousand kilometres. The recorded data is of big size and its processing demand a high computational cost and adequate tool analysis to determine a certain pipeline damage condition. On other hand, the author from UPC and UIS have been bringing its expertise in processing and analysing this type of big data by using mainly Principal Component Analysis (PCA) as an effective tool to detect and locate different damages. In previous papers, multidimensional data matrix was used to locate possible damages along the pipeline, however most of activated points were considered false alarms since they corresponded to weld points. Thus, in this paper it is proposed no considering piecewise weld points (tube sections) and an extension of PCA named Multiway PCA (MPCA) is applied for each each one of the tube sections that form the pipeline. Therefore, if a tube section is found outside from overall indices found by using the MPCA model, an alarm activated in that section and a precise location can be obtained by analyzing only data from that specific tube section.
Wed, 22 Mar 2017 12:43:59 GMThttp://hdl.handle.net/2117/1027972017-03-22T12:43:59ZRuiz Ordóñez, MagdaMujica Delgado, Luis EduardoAlférez Baquero, Edwin SantiagoQuintero, MarioVillamizar Mejía, RodolfoThe history of the hydrocarbons business in Colombia dates back to the early twentieth century where mining and energy sector has been one of the principal pillars for the its development. Thus, the pipelines currently in service have over 30 years and most of them are buried and phenomena like metal losses, corrosion, mechanical stress, strike by excavation machinery and other type of damages are presented. Since it can generate social and environmental problems, monitoring tools and programs should be developed in order to prevent catastrophic situations. However, the maintaining of these structures is very expensive and it is normally developed by foreign companies. In order to overcome this situation, recently the native research institute “Research Institute of Corrosion - CIC (Corporación para la Investigación de la Corrosión)” developed an in-line inspection tool to be operated in Colombian pipelines (especially gas) to get valuable information of their current state along of thousand kilometres. The recorded data is of big size and its processing demand a high computational cost and adequate tool analysis to determine a certain pipeline damage condition. On other hand, the author from UPC and UIS have been bringing its expertise in processing and analysing this type of big data by using mainly Principal Component Analysis (PCA) as an effective tool to detect and locate different damages. In previous papers, multidimensional data matrix was used to locate possible damages along the pipeline, however most of activated points were considered false alarms since they corresponded to weld points. Thus, in this paper it is proposed no considering piecewise weld points (tube sections) and an extension of PCA named Multiway PCA (MPCA) is applied for each each one of the tube sections that form the pipeline. Therefore, if a tube section is found outside from overall indices found by using the MPCA model, an alarm activated in that section and a precise location can be obtained by analyzing only data from that specific tube section.Embedded piezodiagnostics for online structural damage detection based on PCA algorithm
http://hdl.handle.net/2117/102795
Embedded piezodiagnostics for online structural damage detection based on PCA algorithm
Camacho-Navarro, Jhonatan; Ruiz Ordóñez, Magda; Villamizar Mejía, Rodolfo; Mujica Delgado, Luis Eduardo; Ariza, Fabian
This work discusses a methodology used to implement a data-driven strategy for Structural Health Monitoring. First, the instrumentation of the equipment is detailed by describing the main components to be installed in the test structure in order to produce guide d waves. Specifically, an active piezo active system is used for this purpose , which consists of piezoelectric devices attached to the test structure surface and an ac quisition system. Then, the programming procedure to embed the damage detection algorithm is defined. In particular, the mathematical foundations and software requirements for impleme nting the preprocessing stage, baseline model building, and statistical index computation are specified. As a result, the Odroid-U3 computational core has the capability t o perform online damage assessment. Finally, some validation tests are presented through videos and short real time demonstration. Experimental data are recorded from two test specimens: i.) a lab carbon steel pipe loop built to emulate leak scenarios, and ii.) an aluminum plate, where mass adding is used to emulate reversible damages. The results reported i n this work show the high feasibility of the proposal methodology for obtaining an online embedded monitoring system with several advantages such as low cost, easy configuration, expandability and few computational resources
Wed, 22 Mar 2017 12:27:24 GMThttp://hdl.handle.net/2117/1027952017-03-22T12:27:24ZCamacho-Navarro, JhonatanRuiz Ordóñez, MagdaVillamizar Mejía, RodolfoMujica Delgado, Luis EduardoAriza, FabianThis work discusses a methodology used to implement a data-driven strategy for Structural Health Monitoring. First, the instrumentation of the equipment is detailed by describing the main components to be installed in the test structure in order to produce guide d waves. Specifically, an active piezo active system is used for this purpose , which consists of piezoelectric devices attached to the test structure surface and an ac quisition system. Then, the programming procedure to embed the damage detection algorithm is defined. In particular, the mathematical foundations and software requirements for impleme nting the preprocessing stage, baseline model building, and statistical index computation are specified. As a result, the Odroid-U3 computational core has the capability t o perform online damage assessment. Finally, some validation tests are presented through videos and short real time demonstration. Experimental data are recorded from two test specimens: i.) a lab carbon steel pipe loop built to emulate leak scenarios, and ii.) an aluminum plate, where mass adding is used to emulate reversible damages. The results reported i n this work show the high feasibility of the proposal methodology for obtaining an online embedded monitoring system with several advantages such as low cost, easy configuration, expandability and few computational resourcesSobre la inversa de grupo de grafos distancia regulares
http://hdl.handle.net/2117/102776
Sobre la inversa de grupo de grafos distancia regulares
Carmona Mejías, Ángeles
En este trabajo estudiamos cuando la inversa de grupo del Laplacia no com- binatorio de un grafo distancia–regular es una M –matriz. Cuando esto ocurre decimos que el grafo tiene la M –propiedad. Aquí probamos que sólo grafos distancia regulares con diámetro menor que cuatro pueden tener la M –propiedad y damos una caracterización en términos del vector de intersección
Wed, 22 Mar 2017 09:38:08 GMThttp://hdl.handle.net/2117/1027762017-03-22T09:38:08ZCarmona Mejías, ÁngelesEn este trabajo estudiamos cuando la inversa de grupo del Laplacia no com- binatorio de un grafo distancia–regular es una M –matriz. Cuando esto ocurre decimos que el grafo tiene la M –propiedad. Aquí probamos que sólo grafos distancia regulares con diámetro menor que cuatro pueden tener la M –propiedad y damos una caracterización en términos del vector de intersecciónStabbing circles for some sets of Delaunay segments
http://hdl.handle.net/2117/102530
Stabbing circles for some sets of Delaunay segments
Claverol Aguas, Mercè; Khramtcova, Elena; Papadopoulou, Evanthia; Saumell, Maria; Seara Ojea, Carlos
Let S be a set of n segments in the plane such that, for
every segment, its two endpoints are adjacent in the Delaunay triangulation of the set of endpoints of all segments in S. Our goal is to compute all the combinatorially different stabbing circles for S, and the ones with maximum and minimum radius. We exploit a recent result to solve this problem in O(n log n) in two particular cases: (i) all segments in S are parallel; (ii) all segments in S have the same length. We also show that the problem of computing the stabbing circle of minimum radius of a set of n parallel segments of equal length (not necessarily satisfying the Delaunay condition) has an Omega(n log n) lower bound.
Wed, 15 Mar 2017 15:55:08 GMThttp://hdl.handle.net/2117/1025302017-03-15T15:55:08ZClaverol Aguas, MercèKhramtcova, ElenaPapadopoulou, EvanthiaSaumell, MariaSeara Ojea, CarlosLet S be a set of n segments in the plane such that, for
every segment, its two endpoints are adjacent in the Delaunay triangulation of the set of endpoints of all segments in S. Our goal is to compute all the combinatorially different stabbing circles for S, and the ones with maximum and minimum radius. We exploit a recent result to solve this problem in O(n log n) in two particular cases: (i) all segments in S are parallel; (ii) all segments in S have the same length. We also show that the problem of computing the stabbing circle of minimum radius of a set of n parallel segments of equal length (not necessarily satisfying the Delaunay condition) has an Omega(n log n) lower bound.Ability to separate situations with a priori coalition structures by means of symmetric solutions
http://hdl.handle.net/2117/102517
Ability to separate situations with a priori coalition structures by means of symmetric solutions
Giménez Pradales, José Miguel
We say that two situations described by cooperative games are inseparable by a family of solutions, when they obtain the same allocation by all solution concept of this family. The situation of separability by a family of linear solutions reduces to separability from the null game. This is the case of the family of solutions based on marginal contributions weighted by coef¿cients only dependent of the coalition size: the semivalues. It is known that for games with four or more players, the spaces of inseparable games from the null game contain games different to zero-game. We will prove that for ¿ve or more players, when a priori coalition blocks are introduced in the situation described by the game, the dimension of the vector spaces of inseparable games from the null game decreases in an important manner.
Wed, 15 Mar 2017 13:33:58 GMThttp://hdl.handle.net/2117/1025172017-03-15T13:33:58ZGiménez Pradales, José MiguelWe say that two situations described by cooperative games are inseparable by a family of solutions, when they obtain the same allocation by all solution concept of this family. The situation of separability by a family of linear solutions reduces to separability from the null game. This is the case of the family of solutions based on marginal contributions weighted by coef¿cients only dependent of the coalition size: the semivalues. It is known that for games with four or more players, the spaces of inseparable games from the null game contain games different to zero-game. We will prove that for ¿ve or more players, when a priori coalition blocks are introduced in the situation described by the game, the dimension of the vector spaces of inseparable games from the null game decreases in an important manner.Stabbing circles for sets of segments in the plane
http://hdl.handle.net/2117/102514
Stabbing circles for sets of segments in the plane
Claverol Aguas, Mercè; Khramtcova, Elena; Papadopoulou, Evanthia; Saumell, Maria; Seara Ojea, Carlos
Stabbing a set S of n segments in the plane by a line is a well-known problem. In this paper we consider the
variation where the stabbing object is a circle instead of a line. We show that the problem is tightly connected to cluster Voronoi diagrams, in particular, the Hausdorff and the farthest-color Voronoi diagram. Based on these diagrams, we provide a method to compute all the combinatorially different stabbing circles for S, and the stabbing circles with maximum and minimum radius. We give conditions under which our method is fast. These conditions are satisfied if the segments in S are parallel, resulting in a Onlog2n) time algorithm. We also observe that the stabbing circle problem for S can be solved in optimal O(n2) time and space by reducing the problem to computing the stabbing planes for a set of segments in 3D.
Wed, 15 Mar 2017 13:04:35 GMThttp://hdl.handle.net/2117/1025142017-03-15T13:04:35ZClaverol Aguas, MercèKhramtcova, ElenaPapadopoulou, EvanthiaSaumell, MariaSeara Ojea, CarlosStabbing a set S of n segments in the plane by a line is a well-known problem. In this paper we consider the
variation where the stabbing object is a circle instead of a line. We show that the problem is tightly connected to cluster Voronoi diagrams, in particular, the Hausdorff and the farthest-color Voronoi diagram. Based on these diagrams, we provide a method to compute all the combinatorially different stabbing circles for S, and the stabbing circles with maximum and minimum radius. We give conditions under which our method is fast. These conditions are satisfied if the segments in S are parallel, resulting in a Onlog2n) time algorithm. We also observe that the stabbing circle problem for S can be solved in optimal O(n2) time and space by reducing the problem to computing the stabbing planes for a set of segments in 3D.Ordered durability functions estimation for inspection-based data: a computational issue
http://hdl.handle.net/2117/102386
Ordered durability functions estimation for inspection-based data: a computational issue
Serrat Piè, Carles; Moreno Basquens, Laura
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 the Laboratori d’Edificació at the Universitat Politècnica de Catalunya, Spain. The goal of this paper 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 language and the solver SNOPT and we will develop and implement a Survival Estimator Algorithm with Restrictions (SEAR), 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. Application of the methodology to a simulated dataset, which reproduces a real collection data, will be presented and discussed.
Mon, 13 Mar 2017 11:47:37 GMThttp://hdl.handle.net/2117/1023862017-03-13T11:47:37ZSerrat Piè, CarlesMoreno Basquens, LauraThis 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 the Laboratori d’Edificació at the Universitat Politècnica de Catalunya, Spain. The goal of this paper 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 language and the solver SNOPT and we will develop and implement a Survival Estimator Algorithm with Restrictions (SEAR), 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. Application of the methodology to a simulated dataset, which reproduces a real collection data, will be presented and discussed.Solar radiation pressure assisted transfers between Lissajous orbits of the Sun-Earth system
http://hdl.handle.net/2117/102382
Solar radiation pressure assisted transfers between Lissajous orbits of the Sun-Earth system
Stefania, Soldini; Gomez Muntané, Gerard; Masdemont Soler, Josep; Camilla, Colombo; Walker, Scott
This article investigates a propellant-free transfer between Lissa jous orbits in the Sun-Earth system modelled as a photo-gravitational circular restricted three body p roblem. The geometry of the phase space around the L 1 , 2 equilibrium points is exploited to change the amplitudes and phases of the initial Lissajous orbit using the associated hyperbolic invarian t manifolds. The desired Lissajous orbit is reached by cancelling out the instabilities by means o f solar radiation pressure manoeuvres. The acceleration required is controlled by the change in the spacecraft’s reflectivity and angle of incidence of the Sun-line direction. Changes in reflectivit y allow transfers along the x -axis, while re-orientations of the spacecraft move the equilibrium p oints, and the orbits around them, towards the x - y plane. For equilibrium points in the x - y plane, the in-plane centre manifold tends to a center × centre × focus equilibrium. The analytical solution is extended to this general case. An analysis in the magnitude of the manoeuvre required is pres ented for different Lissajous orbit amplitudes and reflectivity, along with a comment on harnessing solar radiation pressure devices
Mon, 13 Mar 2017 11:30:03 GMThttp://hdl.handle.net/2117/1023822017-03-13T11:30:03ZStefania, SoldiniGomez Muntané, GerardMasdemont Soler, JosepCamilla, ColomboWalker, ScottThis article investigates a propellant-free transfer between Lissa jous orbits in the Sun-Earth system modelled as a photo-gravitational circular restricted three body p roblem. The geometry of the phase space around the L 1 , 2 equilibrium points is exploited to change the amplitudes and phases of the initial Lissajous orbit using the associated hyperbolic invarian t manifolds. The desired Lissajous orbit is reached by cancelling out the instabilities by means o f solar radiation pressure manoeuvres. The acceleration required is controlled by the change in the spacecraft’s reflectivity and angle of incidence of the Sun-line direction. Changes in reflectivit y allow transfers along the x -axis, while re-orientations of the spacecraft move the equilibrium p oints, and the orbits around them, towards the x - y plane. For equilibrium points in the x - y plane, the in-plane centre manifold tends to a center × centre × focus equilibrium. The analytical solution is extended to this general case. An analysis in the magnitude of the manoeuvre required is pres ented for different Lissajous orbit amplitudes and reflectivity, along with a comment on harnessing solar radiation pressure devicesA new procedure to calculate the Owen value
http://hdl.handle.net/2117/102250
A new procedure to calculate the Owen value
Puente del Campo, María Albina; Giménez Pradales, José Miguel
In this paper we focus on games with a coalition structure. Particularly, we deal with the Owen value, the coalitional value of the Shapley value, and we provide a computational procedure to calculate this coalitional value in terms of the multilinear extension of the original game.
Thu, 09 Mar 2017 19:07:48 GMThttp://hdl.handle.net/2117/1022502017-03-09T19:07:48ZPuente del Campo, María AlbinaGiménez Pradales, José MiguelIn this paper we focus on games with a coalition structure. Particularly, we deal with the Owen value, the coalitional value of the Shapley value, and we provide a computational procedure to calculate this coalitional value in terms of the multilinear extension of the original game.Técnicas estadísticas aplicadas a la selección de valores para parámetros de metaheurísticas
http://hdl.handle.net/2117/102239
Técnicas estadísticas aplicadas a la selección de valores para parámetros de metaheurísticas
Calvet Liñán, Laura; Juan Pérez, Ángel Alejandro; Serrat Piè, Carles
La mayoría de metaheurísticas incluyen diversos parámetros que influyen en la calidad de su solución. A pesar de esto, el Problema de Selección de Valores para Parámetros no fue formalmente estudiado hasta finales del siglo pasado, y aún hoy en día, muchos investigadores siguen sin utilizar un procedimiento
científico para resolverlo. Escoger unos valores adecuados suele ser una tarea ardua que requiere tiempo. En las últimas décadas, el interés por este problema ha crecido, dando lugar a varios enfoques.
Sin embargo, no hay ninguna metodología ampliamente acceptada por la comunidad científica. Este
trabajo aporta una revisión de los enfoques, y propone una metodología basada en técnicas de Clusterización y Diseño de Experimentos. Con tal de ilustrar su aplicación y mostrar su validez, esta es utilizada para seleccionar valores para los parámetros de un algoritmo híbrido desarrollado para resolver el Problema de Rutas de Vehículos con Múltiples Almacenes, y descrito en [12]
Thu, 09 Mar 2017 16:09:10 GMThttp://hdl.handle.net/2117/1022392017-03-09T16:09:10ZCalvet Liñán, LauraJuan Pérez, Ángel AlejandroSerrat Piè, CarlesLa mayoría de metaheurísticas incluyen diversos parámetros que influyen en la calidad de su solución. A pesar de esto, el Problema de Selección de Valores para Parámetros no fue formalmente estudiado hasta finales del siglo pasado, y aún hoy en día, muchos investigadores siguen sin utilizar un procedimiento
científico para resolverlo. Escoger unos valores adecuados suele ser una tarea ardua que requiere tiempo. En las últimas décadas, el interés por este problema ha crecido, dando lugar a varios enfoques.
Sin embargo, no hay ninguna metodología ampliamente acceptada por la comunidad científica. Este
trabajo aporta una revisión de los enfoques, y propone una metodología basada en técnicas de Clusterización y Diseño de Experimentos. Con tal de ilustrar su aplicación y mostrar su validez, esta es utilizada para seleccionar valores para los parámetros de un algoritmo híbrido desarrollado para resolver el Problema de Rutas de Vehículos con Múltiples Almacenes, y descrito en [12]