... Estadística en el control de calidad. Información general. Autores: Maria Angels Colomer; Edi... more ... Estadística en el control de calidad. Información general. Autores: Maria Angels Colomer; Editores: Universitat de Lleida; Año de publicación: 1996; País: España; Idioma: Español; ISBN : 84-89727-21-X; ¿En qué Biblioteca Universitaria española puedo encontrar este libro? ...
International Journal of Computers Communications & Control, 2009
It is well known that any irreducible and aperiodic Markov chain has exactly one stationary distr... more It is well known that any irreducible and aperiodic Markov chain has exactly one stationary distribution, and for any arbitrary initial distribution, the sequence of distributions at time n converges to the stationary distribution, that is, the Markov chain is approaching equilibrium as n → ∞. In this paper, a characterization of the aperiodicity in existential terms of some state is given. At the same time, a P system with external output is associated with any irreducible Markov chain. The designed system provides the aperiodicity of that Markov chain and spends a polynomial amount of resources with respect to the size of the input. A comparative analysis with respect to another known solution is described.
It is well known that any irreducible and aperiodic Markov chain has exactly one stationary distr... more It is well known that any irreducible and aperiodic Markov chain has exactly one stationary distribution, and for any arbitrary initial distribution, the sequence of distributions at time n converges to the stationary distribution, that is, the Markov chain is approaching equilibrium as n → ∞. In this paper, a characterization of the aperiodicity in existential terms of some state is given. At the same time, a P system with external output is associated with any irreducible Markov chain. The designed system provides the aperiodicity of that Markov chain and spends a polynomial amount of resources with respect to the size of the input. A formal verification of this solution is presented and a comparative analysis with respect to another known solution is described.
In this paper we approach the problem of hierarchical clustering through membrane computing. A sp... more In this paper we approach the problem of hierarchical clustering through membrane computing. A specific P system with external output is designed for each Boolean matrix associated with a finite set of individuals. The computation of the system allows us to obtain one of the possible classifications in a non-deterministic way. The amount of resources required in the construction is polynomial in the number of individuals and of characteristics analyzed.
Using probabilistic functional multi-environment P-System we model the dynamics of a newt populat... more Using probabilistic functional multi-environment P-System we model the dynamics of a newt population living in two streams. The newt species is threatened by anthropic factors. The availability of a validated model to study the population's dynamics will enable managers to take decisions in order to conserve the species.
Raptors Ringing recoveries Spain decreasing trend is not evident. The results of the analysis of ... more Raptors Ringing recoveries Spain decreasing trend is not evident. The results of the analysis of different environmental and socioeconomic factors affecting bird electrocution rates are similar between ringed birds and traditional power line surveys. Our modelling suggests three common factors that influence mortality rates: number of hunted rabbits, tree coverage and length of the power line network. Thus, the use of alternative information sources to detect high mortality areas due to electrocution by power lines may be a useful tool to complement other methods.
Uno de los principales problemas que surgen a la hora de diseñar o analizar hidráulicamente cauce... more Uno de los principales problemas que surgen a la hora de diseñar o analizar hidráulicamente cauces revestidos de escollera es la incertidumbre asociada a la estimación de los coeficientes de resistencia al flujo. El presente trabajo tiene por objeto contribuir a mejorar la capacidad predictiva delfactor de fricción de Darcy-Weisbach (f), mediante la evaluación (ajuste, validación y compración) de seis medelos de resistencia al flujo circualnte sobre escollera. Los modelos evaluados se fundamentan en leyes de distribución vertical de velocidad del flujo sobre lechos granulares: la ley logaítimica de Prandtl-Karman, su alternativa potencial y cuantro ecuaciones propustas para flujo macrorrugoso. La base empírica se halla integrada por 236 datos tomados en canales de campo y de laboratorio que reúnen características hidráulicas granulamétricas identificables con revestimientos de escollera. Se concluye que las ecuaciones para flujo macrorrugoso logran el mejor ajuste global, aunque sin...
En ríos constituidos por material grueso heterométrico y flujo de baja sumersión relativa resulta... more En ríos constituidos por material grueso heterométrico y flujo de baja sumersión relativa resulta difícil definir y medir variables relacionadas con la geometría de la sección transversal del cauce. En este artículo se ha calibrado, validado y comparado un modelo que permite relacionar el caudal de la corriente y su velocidad media sin incluir variables relativas a la geometría de la sección. Se seleccionó para ell un conjunto de 904 datos pertenecientes a más de 400 tramos de diferentes ríos con lecho granular de tamaño grava, canto o bolo. Se ha logrado un mejor ajuste cuanto mayor es el percentil granulométrico con el que se expresa el tamaño característico del sedimento. La capacidad explicativa del modelo ajustado es equiparable a la de la ecuación logarítmica tipo Keulegan y superior a la de la ecuación que no requiere una estimación explícita del coeficiente de resistencia al flujo. El ajuste segmentado del modelo estudiado, tomando como criterio de corte un valor de la pendi...
As obligate scavengers, vultures are entirely dependent on carrion resources. In this study we mo... more As obligate scavengers, vultures are entirely dependent on carrion resources. In this study we model the carrion ecology of an ecosystem in Swaziland which is home to the densest breeding population of the African White-backed Vulture (Gyps africanus). We collected data on life-history parameters of the avian scavenging guild of the area as well as the potential food available from the ungulate fauna. By using novel Population Dynamics P-Systems we show that carrion provided by wild ungulates biomass is currently enough to sustain this vulture species. However, in light of forecasted population increases, food will become limiting. We discuss the significance of mass closure of supplementary feeding stations in Swaziland which now forces these birds to forage farther afield endangering them to poisoning events. We put these results in the context of biomass management and suggest conservation actions to secure the viability of vulture populations and the important ecosystem services they provide.
Three models of flow resistance (a Keulegan-type logarithmic law and two models developed for lar... more Three models of flow resistance (a Keulegan-type logarithmic law and two models developed for large-scale roughness conditions: the full logarithmic law and a model based on an inflectional velocity profile) were calibrated, validated and compared using an extensive database (N = 1,533) from rivers and flumes, representative of a wide hydraulic and geomorphologic range in the field of gravel-bed and mountain channels. It is preferable to apply the model based on an inflectional velocity profile in the relative submergence (y/d 90) interval between 0.5 and 15, while the full logarithmic law is preferable for values below 0.5. For high relative submergence, above 15, either the logarithmic law or the full logarithmic law can be applied. The models fitted to the coarser percentiles are preferable to those fitted to the median diameter, owing to the higher explanatory power achieved by setting a model, the smaller difference in the goodness-of-fit between the different models and the lower influence of the origin of the data (river or flume).
... Estadística en el control de calidad. Información general. Autores: Maria Angels Colomer; Edi... more ... Estadística en el control de calidad. Información general. Autores: Maria Angels Colomer; Editores: Universitat de Lleida; Año de publicación: 1996; País: España; Idioma: Español; ISBN : 84-89727-21-X; ¿En qué Biblioteca Universitaria española puedo encontrar este libro? ...
International Journal of Computers Communications & Control, 2009
It is well known that any irreducible and aperiodic Markov chain has exactly one stationary distr... more It is well known that any irreducible and aperiodic Markov chain has exactly one stationary distribution, and for any arbitrary initial distribution, the sequence of distributions at time n converges to the stationary distribution, that is, the Markov chain is approaching equilibrium as n → ∞. In this paper, a characterization of the aperiodicity in existential terms of some state is given. At the same time, a P system with external output is associated with any irreducible Markov chain. The designed system provides the aperiodicity of that Markov chain and spends a polynomial amount of resources with respect to the size of the input. A comparative analysis with respect to another known solution is described.
It is well known that any irreducible and aperiodic Markov chain has exactly one stationary distr... more It is well known that any irreducible and aperiodic Markov chain has exactly one stationary distribution, and for any arbitrary initial distribution, the sequence of distributions at time n converges to the stationary distribution, that is, the Markov chain is approaching equilibrium as n → ∞. In this paper, a characterization of the aperiodicity in existential terms of some state is given. At the same time, a P system with external output is associated with any irreducible Markov chain. The designed system provides the aperiodicity of that Markov chain and spends a polynomial amount of resources with respect to the size of the input. A formal verification of this solution is presented and a comparative analysis with respect to another known solution is described.
In this paper we approach the problem of hierarchical clustering through membrane computing. A sp... more In this paper we approach the problem of hierarchical clustering through membrane computing. A specific P system with external output is designed for each Boolean matrix associated with a finite set of individuals. The computation of the system allows us to obtain one of the possible classifications in a non-deterministic way. The amount of resources required in the construction is polynomial in the number of individuals and of characteristics analyzed.
Using probabilistic functional multi-environment P-System we model the dynamics of a newt populat... more Using probabilistic functional multi-environment P-System we model the dynamics of a newt population living in two streams. The newt species is threatened by anthropic factors. The availability of a validated model to study the population's dynamics will enable managers to take decisions in order to conserve the species.
Raptors Ringing recoveries Spain decreasing trend is not evident. The results of the analysis of ... more Raptors Ringing recoveries Spain decreasing trend is not evident. The results of the analysis of different environmental and socioeconomic factors affecting bird electrocution rates are similar between ringed birds and traditional power line surveys. Our modelling suggests three common factors that influence mortality rates: number of hunted rabbits, tree coverage and length of the power line network. Thus, the use of alternative information sources to detect high mortality areas due to electrocution by power lines may be a useful tool to complement other methods.
Uno de los principales problemas que surgen a la hora de diseñar o analizar hidráulicamente cauce... more Uno de los principales problemas que surgen a la hora de diseñar o analizar hidráulicamente cauces revestidos de escollera es la incertidumbre asociada a la estimación de los coeficientes de resistencia al flujo. El presente trabajo tiene por objeto contribuir a mejorar la capacidad predictiva delfactor de fricción de Darcy-Weisbach (f), mediante la evaluación (ajuste, validación y compración) de seis medelos de resistencia al flujo circualnte sobre escollera. Los modelos evaluados se fundamentan en leyes de distribución vertical de velocidad del flujo sobre lechos granulares: la ley logaítimica de Prandtl-Karman, su alternativa potencial y cuantro ecuaciones propustas para flujo macrorrugoso. La base empírica se halla integrada por 236 datos tomados en canales de campo y de laboratorio que reúnen características hidráulicas granulamétricas identificables con revestimientos de escollera. Se concluye que las ecuaciones para flujo macrorrugoso logran el mejor ajuste global, aunque sin...
En ríos constituidos por material grueso heterométrico y flujo de baja sumersión relativa resulta... more En ríos constituidos por material grueso heterométrico y flujo de baja sumersión relativa resulta difícil definir y medir variables relacionadas con la geometría de la sección transversal del cauce. En este artículo se ha calibrado, validado y comparado un modelo que permite relacionar el caudal de la corriente y su velocidad media sin incluir variables relativas a la geometría de la sección. Se seleccionó para ell un conjunto de 904 datos pertenecientes a más de 400 tramos de diferentes ríos con lecho granular de tamaño grava, canto o bolo. Se ha logrado un mejor ajuste cuanto mayor es el percentil granulométrico con el que se expresa el tamaño característico del sedimento. La capacidad explicativa del modelo ajustado es equiparable a la de la ecuación logarítmica tipo Keulegan y superior a la de la ecuación que no requiere una estimación explícita del coeficiente de resistencia al flujo. El ajuste segmentado del modelo estudiado, tomando como criterio de corte un valor de la pendi...
As obligate scavengers, vultures are entirely dependent on carrion resources. In this study we mo... more As obligate scavengers, vultures are entirely dependent on carrion resources. In this study we model the carrion ecology of an ecosystem in Swaziland which is home to the densest breeding population of the African White-backed Vulture (Gyps africanus). We collected data on life-history parameters of the avian scavenging guild of the area as well as the potential food available from the ungulate fauna. By using novel Population Dynamics P-Systems we show that carrion provided by wild ungulates biomass is currently enough to sustain this vulture species. However, in light of forecasted population increases, food will become limiting. We discuss the significance of mass closure of supplementary feeding stations in Swaziland which now forces these birds to forage farther afield endangering them to poisoning events. We put these results in the context of biomass management and suggest conservation actions to secure the viability of vulture populations and the important ecosystem services they provide.
Three models of flow resistance (a Keulegan-type logarithmic law and two models developed for lar... more Three models of flow resistance (a Keulegan-type logarithmic law and two models developed for large-scale roughness conditions: the full logarithmic law and a model based on an inflectional velocity profile) were calibrated, validated and compared using an extensive database (N = 1,533) from rivers and flumes, representative of a wide hydraulic and geomorphologic range in the field of gravel-bed and mountain channels. It is preferable to apply the model based on an inflectional velocity profile in the relative submergence (y/d 90) interval between 0.5 and 15, while the full logarithmic law is preferable for values below 0.5. For high relative submergence, above 15, either the logarithmic law or the full logarithmic law can be applied. The models fitted to the coarser percentiles are preferable to those fitted to the median diameter, owing to the higher explanatory power achieved by setting a model, the smaller difference in the goodness-of-fit between the different models and the lower influence of the origin of the data (river or flume).
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