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L-Systems allow for the efficient procedeural generation of trees to be used for rendering in video games and simulations. Currently, however, it is difficult to engineer grammars that mimic the behaviours of real life trees in 3 dimensions. To be able to deduce them, the skeleton of a tree can be used to train a model and generate an L-system for a given tree in particular. The aim of this paper is to provide a pipeline to isolate these skeletons from images of a tree, using Neural Radiance Fields (NeRFs) to reconstruct the tree, and using Laplacian Based Contraction to retrieve the underlying skeleton. We find that this approach leads to 3-dimensional topologies that very closely resemble the given tree., CSE3000 Research Project, Computer Science and Engineering

Skeletonization, a crucial step in pore network modeling, traditionally involves the extraction of skeleton pixels from binarized, segmented X-ray images of porous materials. However, this conventional approach often suffers from user bias during segmentation, potentially leading to the loss of essential image details. This study addresses this limitation by developing deep learning model, called PoreSkel, designed to directly perform skeletonization and distance map extraction from unprocessed grayscale images, thus eliminating the need for additional image processing steps. The model was trained, validated, and tested using an expansive databank of micro-CT images from 20 distinct sandstones, carbonates, and sand pack samples, a total of 10,240 images, with each sample represented by a cube of size 5123. A fifth of these images, specifically 15.6 % from sixteen sandstone and sand pack samples, were used for training, while the remainder served for model validation (4.4 %) and extensive testing (80 %). PoreSkel showed an excellent performance, achieving a mean f1-score of 0.964 for skeletonization and an RMSE of 0.057 for distance map extraction during the testing phase. Our assessments revealed that the model is robust to bias toward the majority class, namely the background pixels. Furthermore, the model showed high generality, maintaining its performance when tested using unseen images from three carbonates and an additional sandstone. Notably, PoreSkel effectively handles disruptions caused often by the presence of minerals in pore spaces and perturbations on pore boundaries - a common challenge for the medial axis technique - resulting in fewer nodes (i.e., pore junctions) and pore coordination numbers, but a higher number of connected skeletons. Therefore, PoreSkel provided a more precise and representative pore structures of porous material that is needed for accurate pore network generation and modeling.

Improving mechanical topology optimization (TO) results by substituting biomimetic beams is one possibility to achieve designs of mechanical components that are highly sustainable and show good mechanical performance. Because of their geometric complexity, such designs were found to be well-suited for production by laser additive manufacturing. One obstacle of incorporating biomimetics beams in TO designs is the lack of detailed design methodologies. Röver et al. [“Methodology for integrating biomimetic beams in abstracted topology optimization results,” in Proceedings of the ASME 2022 International Mechanical Engineering Congress and Exposition. Volume 4: Biomedical and Biotechnology; Design, Systems, and Complexity Columbus, OH, 30 October-3 November (ASME, New York, 2022)] proposed a corresponding design concept. Building on their concept, we present in this work a detailed methodology for abstraction of TO results to a design consisting of ball nodes and cylindrical beams. Using such an auxiliary design, the internal forces and moments of the beams can be evaluated to allow for the substitution of suitable biomimetic beams to generate biomimetic component designs in a next step. We present a skeletonization algorithm based on the potential field approach. Using the skeletonization and an additional analysis of the dimensions of the beams in the TO result, the algorithm develops an auxiliary design of the original TO result. The final algorithm was applied to three common TO results to obtain one auxiliary component design each. The developed algorithm was found to generate abstractions that were well-suited for use in the methodology proposed in Röver et al. [“Methodology for integrating biomimetic beams in abstracted topology optimization results,” in Proceedings of the ASME 2022 International Mechanical Engineering Congress and Exposition. Volume 4: Biomedical and Biotechnology; Design, Systems, and Complexity Columbus, OH, 30 October-3 November (ASME, New Yor

We present a new technique for specifying rotations of 3D shapes around axes inferred from the local shape structure, in support of 3D exploration and manipulation tasks. We compute such axes by extracting approximations of the 3D curve skeleton of such shapes using the skeletons of their 2D image silhouettes and depth information present in the Z buffer. Our method allows specifying rotations around parts of arbitrary 3D shapes with a single click, works in real time for large scenes, can be easily added to any OpenGL-based scene viewer, and is simple to implement. We compare our method with classical trackball rotation, both in isolation and in combination, in a controlled user study. Our results show that, when combined with trackball, skeleton-based rotation reduces task completion times and increases user satisfaction, while not introducing additional costs, being thus an interesting addition to the palette of 3D manipulation tools.

We consider thinning methods to extract one dimensional skeletons from discrete objects defined on the body-centered cubic (bcc) lattice. In Strand (2004), a condition has been given that guarantees the preservation of the object's topology in such a thinning process. In this paper, we present stronger conditions that even allow the topological invariant point removal in a parallelized process. These conditions for p-simplicity can be efficiently evaluated which leads to a very fast thinning process. We show that p-simplicity is a new concept that cannot be obtained by adapting the checking plane conditions of Tsao and Fu to the bcc lattice. Furthermore, we introduce distance information and an optional pruning mechanism into the thinning process to improve the quality of the resulting skeletons. The presented results show that our method generates high quality skeletons that reproduce the symmetries of the models even under the condition of added noise and contain only very few spurious branches. The presented running times demonstrate the linear run-time behavior of our algorithm and the speedup that is achieved by the parallelization. (C) 2022 Elsevier Ltd. All rights reserved.

Plant–insect interactions in the fossil record are, as yet, sparsely known and understudied. Here, we document evidence of a new type of insect skeletonization on Abroma augustum (L.) L. f. (Malvaceae) leaf remains fromthe latest Neogene (Pliocene) sediments of Chotanagpur plateau, Jharkhand, eastern India. This unique skeletonization feeding trace attributable to herbivorous insects occurs all over the surfaces of our recovered Pliocene leaf remains. In the skeletonized area, the interveinal tissues are completely removed leaving behind only the tough leaf veins. This type of insect feeding behaviour is documented for the first time on Indian Cenozoic leaf remains. Based on published data, as well as our survey of modern forests adjacent to the fossil locality, we suggest that probable damage inducers of this skeletonization on Abroma Jacq. fossil leaves might be Chrysomelid (Coleopteran) beetles. This finding also reveals that specific insect feeding damage, such as the one presented here, can reveal similarity of environments despite the difference of plant species observed. Such results strengthen the importance of using plant–insect interactions on leaves as a complementary proxy to others revealing paleoenvironmental conditions.

One of the most important tasks regarding autonomous mobile robots is to plan a path for movement. Given a pre-built map, a robot is able to follow a path that is determined manually by setting way points on the map prior to exploration. However, for cases without pre-built maps, a robot has to derive its path while traveling autonomously and analyzing the surrouding environment. In this paper, we propose a method of path planning for autonomous movement under unknown environments in the case where a pre-built map does not exist. This system successfully determines way points on a road following the skeleton extracted by combining multiple data processing algorithms.

Plant–insect interactions in the fossil record are, as yet, sparsely known and understudied. Here, we document evidence of a new type of insect skeletonization on Abroma augustum (L.) L. f. (Malvaceae) leaf remains fromthe latest Neogene (Pliocene) sediments of Chotanagpur plateau, Jharkhand, eastern India. This unique skeletonization feeding trace attributable to herbivorous insects occurs all over the surfaces of our recovered Pliocene leaf remains. In the skeletonized area, the interveinal tissues are completely removed leaving behind only the tough leaf veins. This type of insect feeding behaviour is documented for the first time on Indian Cenozoic leaf remains. Based on published data, as well as our survey of modern forests adjacent to the fossil locality, we suggest that probable damage inducers of this skeletonization on Abroma Jacq. fossil leaves might be Chrysomelid (Coleopteran) beetles. This finding also reveals that specific insect feeding damage, such as the one presented here, can reveal similarity of environments despite the difference of plant species observed. Such results strengthen the importance of using plant–insect interactions on leaves as a complementary proxy to others revealing paleoenvironmental conditions.

Skeletons are well-known descriptors used for analysis and processing of 2D binary images. Recently, dense skeletons have been proposed as an extension of classical skeletons as a dual encoding for 2D grayscale and color images. Yet, their encoding power, measured by the quality and size of the encoded image, and how these metrics depend on selected encoding parameters, has not been formally evaluated. In this paper, we fill this gap with two main contributions. First, we improve the encoding power of dense skeletons by effective layer selection heuristics, a refined skeleton pixel-chain encoding, and a postprocessing compression scheme. Secondly, we propose a benchmark to assess the encoding power of dense skeletons for a wide set of natural and synthetic color and grayscale images. We use this benchmark to derive optimal parameters for dense skeletons. Our method, called Compressing Dense Medial Descriptors (CDMD), achieves higher-compression ratios at similar quality to the well-known JPEG technique and, thereby, shows that skeletons can be an interesting option for lossy image encoding.

[ES] En general, los modelos informáticos son construidos para representar una realidad cuya complejidad imposibilita su análisis analítico. En el caso particular de las redes de distribución de agua, constituyen una potente herramienta de obtención de información útil para la toma de decisiones relacionadas con la operación de la red y la gestión del recurso. El problema surge cuando, en la búsqueda de aumentar la fiabilidad, suelen incorporarse gran parte de los elementos constitutivos de las redes, incluso aquellos que podrían ser considerados prescindibles. Esto conlleva a la obtención de modelos de distribución muy completos que si bien cumplen la función de emular correctamente la realidad que representan, suelen tornarse demasiado complejos para ciertos tipos de análisis cuando la red posee dimensiones topológicas de gran magnitud. Un caso particular de lo mencionado son los modelos de operación y monitoreo de redes de abastecimiento en tiempo real. Estos sistemas deben ser lo suficientemente sencillos como para poder interpretar fácilmente los fenómenos que ocurren en el sistema. Otro caso común es el análisis de sustitución de tuberías para mejorar el funcionamiento de la red, muy utilizado por las empresas abastecedoras en su búsqueda por encontrar la forma más eficiente de invertir el dinero disponible para rehabilitación. En ambos casos, el trabajo se realiza con programas informáticos que ejecutan numerosas simulaciones variando diferentes parámetros topológicos e hidráulicos que conseguir la solución óptima que cumpla los criterios de cálculo prefijados. Evidentemente, la rapidez con que se ejecuta el algoritmo está directamente relacionada con las características topológicas de la red: a mayor complejidad y tamaño, mayor es el tiempo empleado. A partir de lo anterior, surge la necesidad de realizar simplificaciones en aquellas infraestructuras cuyas dimensiones generan tiempos de simulación tan excesivos que dificultan e incluso imposibilitan la ejecu, [EN] In general, computer models are built to represent a reality whose complexity makes analytical analysis impossible. In the particular case of water distribution networks, they constitute a powerful tool for obtaining useful information for making decisions related to the operation of the network and the management of the resource. The problem arises when, in the search to increase reliability, a large part of the constituent elements of the networks are usually incorporated, even those that could be considered expendable. This leads to obtaining very complete distribution models that, although they fulfill the function of correctly emulating the reality they represent, tend to become too complex for certain types of analysis when the network has large topological dimensions. A particular case of the aforementioned are the models of operation and monitoring of supply networks in real time. These systems must be simple enough to be able to easily interpret the phenomena that occur in the system. Another common case is the analysis of pipe substitution to improve the operation of the network, widely used by supply companies in their search to find the most efficient way to invest the money available for rehabilitation. In both cases, the work is carried out with computer programs that run numerous simulations varying different topological and hydraulic parameters to achieve the optimal solution that meets the predetermined calculation criteria. Obviously, the speed with which the algorithm is executed is directly related to the topological characteristics of the network: the greater the complexity and size, the greater the time taken. From the above, the need arises to carry out simplifications in those infrastructures whose dimensions generate simulation times so excessive that they make it difficult or even impossible to execute optimization analyzes. This simplification must be done using strict topological and hydraulic criteria, since the results obtained in, [CA] En general, els models informàtics són construïts per a representar una realitat la complexitat de la qual impossibilita la seua anàlisi analítica. En el cas particular de les xarxes de distribució d'aigua, constituïxen una potent ferramenta d'obtenció d'informació útil per a la presa de decisions relacionades amb l'operació de la xarxa i la gestió del recurs. El problema sorgix quan, en la busca d'augmentar la fiabilitat, solen incorporar-se gran part dels elements constitutius de les xarxes, inclús aquells que podrien ser considerats prescindibles. Açò comporta a l'obtenció de models de distribució molt complets que si bé complixen la funció d'emular correctament la realitat que representen, solen tornar-se massa complexos per a certs tipus d'anàlisi quan la xarxa posseïx dimensions topològiques de gran magnitud. Un cas particular d'allò que s'ha mencionat són els models d'operació i monitoreo de xarxes d'abastiment en temps real. Estos sistemes han de ser prou senzills com per a poder interpretar fàcilment els fenòmens que ocorren en el sistema. Un altre cas comuna és l'anàlisi de substitució de canonades per a millorar el funcionament de la xarxa, molt utilitzat per les empreses abastidores en la seua busca per trobar la forma més eficient d'invertir els diners disponibles per a rehabilitació. En ambdós casos, el treball es realitza amb programes informàtics que executen nombroses simulacions variant diferents paràmetres topològics i hidràulics que aconseguir la solució òptima que complisca els criteris de càlcul prefixats. Evidentment, la rapidesa amb què s'executa l'algoritme està directament relacionada amb les característiques topològiques de la xarxa: a major complexitat i grandària, major és el temps empleat. A partir de l'anterior, sorgix la necessitat de realitzar simplificacions en aquelles infraestructures les dimensions de les quals generen temps de simulació tan excessius que dificulten i inclús impossibiliten l'execució d'anàlisi d'optimització

[ES] En general, los modelos informáticos son construidos para representar una realidad cuya complejidad imposibilita su análisis analítico. En el caso particular de las redes de distribución de agua, constituyen una potente herramienta de obtención de información útil para la toma de decisiones relacionadas con la operación de la red y la gestión del recurso. El problema surge cuando, en la búsqueda de aumentar la fiabilidad, suelen incorporarse gran parte de los elementos constitutivos de las redes, incluso aquellos que podrían ser considerados prescindibles. Esto conlleva a la obtención de modelos de distribución muy completos que si bien cumplen la función de emular correctamente la realidad que representan, suelen tornarse demasiado complejos para ciertos tipos de análisis cuando la red posee dimensiones topológicas de gran magnitud. Un caso particular de lo mencionado son los modelos de operación y monitoreo de redes de abastecimiento en tiempo real. Estos sistemas deben ser lo suficientemente sencillos como para poder interpretar fácilmente los fenómenos que ocurren en el sistema. Otro caso común es el análisis de sustitución de tuberías para mejorar el funcionamiento de la red, muy utilizado por las empresas abastecedoras en su búsqueda por encontrar la forma más eficiente de invertir el dinero disponible para rehabilitación. En ambos casos, el trabajo se realiza con programas informáticos que ejecutan numerosas simulaciones variando diferentes parámetros topológicos e hidráulicos que conseguir la solución óptima que cumpla los criterios de cálculo prefijados. Evidentemente, la rapidez con que se ejecuta el algoritmo está directamente relacionada con las características topológicas de la red: a mayor complejidad y tamaño, mayor es el tiempo empleado. A partir de lo anterior, surge la necesidad de realizar simplificaciones en aquellas infraestructuras cuyas dimensiones generan tiempos de simulación tan excesivos que dificultan e incluso imposibilitan la ejecu, [EN] In general, computer models are built to represent a reality whose complexity makes analytical analysis impossible. In the particular case of water distribution networks, they constitute a powerful tool for obtaining useful information for making decisions related to the operation of the network and the management of the resource. The problem arises when, in the search to increase reliability, a large part of the constituent elements of the networks are usually incorporated, even those that could be considered expendable. This leads to obtaining very complete distribution models that, although they fulfill the function of correctly emulating the reality they represent, tend to become too complex for certain types of analysis when the network has large topological dimensions. A particular case of the aforementioned are the models of operation and monitoring of supply networks in real time. These systems must be simple enough to be able to easily interpret the phenomena that occur in the system. Another common case is the analysis of pipe substitution to improve the operation of the network, widely used by supply companies in their search to find the most efficient way to invest the money available for rehabilitation. In both cases, the work is carried out with computer programs that run numerous simulations varying different topological and hydraulic parameters to achieve the optimal solution that meets the predetermined calculation criteria. Obviously, the speed with which the algorithm is executed is directly related to the topological characteristics of the network: the greater the complexity and size, the greater the time taken. From the above, the need arises to carry out simplifications in those infrastructures whose dimensions generate simulation times so excessive that they make it difficult or even impossible to execute optimization analyzes. This simplification must be done using strict topological and hydraulic criteria, since the results obtained in, [CA] En general, els models informàtics són construïts per a representar una realitat la complexitat de la qual impossibilita la seua anàlisi analítica. En el cas particular de les xarxes de distribució d'aigua, constituïxen una potent ferramenta d'obtenció d'informació útil per a la presa de decisions relacionades amb l'operació de la xarxa i la gestió del recurs. El problema sorgix quan, en la busca d'augmentar la fiabilitat, solen incorporar-se gran part dels elements constitutius de les xarxes, inclús aquells que podrien ser considerats prescindibles. Açò comporta a l'obtenció de models de distribució molt complets que si bé complixen la funció d'emular correctament la realitat que representen, solen tornar-se massa complexos per a certs tipus d'anàlisi quan la xarxa posseïx dimensions topològiques de gran magnitud. Un cas particular d'allò que s'ha mencionat són els models d'operació i monitoreo de xarxes d'abastiment en temps real. Estos sistemes han de ser prou senzills com per a poder interpretar fàcilment els fenòmens que ocorren en el sistema. Un altre cas comuna és l'anàlisi de substitució de canonades per a millorar el funcionament de la xarxa, molt utilitzat per les empreses abastidores en la seua busca per trobar la forma més eficient d'invertir els diners disponibles per a rehabilitació. En ambdós casos, el treball es realitza amb programes informàtics que executen nombroses simulacions variant diferents paràmetres topològics i hidràulics que aconseguir la solució òptima que complisca els criteris de càlcul prefixats. Evidentment, la rapidesa amb què s'executa l'algoritme està directament relacionada amb les característiques topològiques de la xarxa: a major complexitat i grandària, major és el temps empleat. A partir de l'anterior, sorgix la necessitat de realitzar simplificacions en aquelles infraestructures les dimensions de les quals generen temps de simulació tan excessius que dificulten i inclús impossibiliten l'execució d'anàlisi d'optimització

[ES] En general, los modelos informáticos son construidos para representar una realidad cuya complejidad imposibilita su análisis analítico. En el caso particular de las redes de distribución de agua, constituyen una potente herramienta de obtención de información útil para la toma de decisiones relacionadas con la operación de la red y la gestión del recurso. El problema surge cuando, en la búsqueda de aumentar la fiabilidad, suelen incorporarse gran parte de los elementos constitutivos de las redes, incluso aquellos que podrían ser considerados prescindibles. Esto conlleva a la obtención de modelos de distribución muy completos que si bien cumplen la función de emular correctamente la realidad que representan, suelen tornarse demasiado complejos para ciertos tipos de análisis cuando la red posee dimensiones topológicas de gran magnitud. Un caso particular de lo mencionado son los modelos de operación y monitoreo de redes de abastecimiento en tiempo real. Estos sistemas deben ser lo suficientemente sencillos como para poder interpretar fácilmente los fenómenos que ocurren en el sistema. Otro caso común es el análisis de sustitución de tuberías para mejorar el funcionamiento de la red, muy utilizado por las empresas abastecedoras en su búsqueda por encontrar la forma más eficiente de invertir el dinero disponible para rehabilitación. En ambos casos, el trabajo se realiza con programas informáticos que ejecutan numerosas simulaciones variando diferentes parámetros topológicos e hidráulicos que conseguir la solución óptima que cumpla los criterios de cálculo prefijados. Evidentemente, la rapidez con que se ejecuta el algoritmo está directamente relacionada con las características topológicas de la red: a mayor complejidad y tamaño, mayor es el tiempo empleado. A partir de lo anterior, surge la necesidad de realizar simplificaciones en aquellas infraestructuras cuyas dimensiones generan tiempos de simulación tan excesivos que dificultan e incluso imposibilitan la ejecu, [EN] In general, computer models are built to represent a reality whose complexity makes analytical analysis impossible. In the particular case of water distribution networks, they constitute a powerful tool for obtaining useful information for making decisions related to the operation of the network and the management of the resource. The problem arises when, in the search to increase reliability, a large part of the constituent elements of the networks are usually incorporated, even those that could be considered expendable. This leads to obtaining very complete distribution models that, although they fulfill the function of correctly emulating the reality they represent, tend to become too complex for certain types of analysis when the network has large topological dimensions. A particular case of the aforementioned are the models of operation and monitoring of supply networks in real time. These systems must be simple enough to be able to easily interpret the phenomena that occur in the system. Another common case is the analysis of pipe substitution to improve the operation of the network, widely used by supply companies in their search to find the most efficient way to invest the money available for rehabilitation. In both cases, the work is carried out with computer programs that run numerous simulations varying different topological and hydraulic parameters to achieve the optimal solution that meets the predetermined calculation criteria. Obviously, the speed with which the algorithm is executed is directly related to the topological characteristics of the network: the greater the complexity and size, the greater the time taken. From the above, the need arises to carry out simplifications in those infrastructures whose dimensions generate simulation times so excessive that they make it difficult or even impossible to execute optimization analyzes. This simplification must be done using strict topological and hydraulic criteria, since the results obtained in, [CA] En general, els models informàtics són construïts per a representar una realitat la complexitat de la qual impossibilita la seua anàlisi analítica. En el cas particular de les xarxes de distribució d'aigua, constituïxen una potent ferramenta d'obtenció d'informació útil per a la presa de decisions relacionades amb l'operació de la xarxa i la gestió del recurs. El problema sorgix quan, en la busca d'augmentar la fiabilitat, solen incorporar-se gran part dels elements constitutius de les xarxes, inclús aquells que podrien ser considerats prescindibles. Açò comporta a l'obtenció de models de distribució molt complets que si bé complixen la funció d'emular correctament la realitat que representen, solen tornar-se massa complexos per a certs tipus d'anàlisi quan la xarxa posseïx dimensions topològiques de gran magnitud. Un cas particular d'allò que s'ha mencionat són els models d'operació i monitoreo de xarxes d'abastiment en temps real. Estos sistemes han de ser prou senzills com per a poder interpretar fàcilment els fenòmens que ocorren en el sistema. Un altre cas comuna és l'anàlisi de substitució de canonades per a millorar el funcionament de la xarxa, molt utilitzat per les empreses abastidores en la seua busca per trobar la forma més eficient d'invertir els diners disponibles per a rehabilitació. En ambdós casos, el treball es realitza amb programes informàtics que executen nombroses simulacions variant diferents paràmetres topològics i hidràulics que aconseguir la solució òptima que complisca els criteris de càlcul prefixats. Evidentment, la rapidesa amb què s'executa l'algoritme està directament relacionada amb les característiques topològiques de la xarxa: a major complexitat i grandària, major és el temps empleat. A partir de l'anterior, sorgix la necessitat de realitzar simplificacions en aquelles infraestructures les dimensions de les quals generen temps de simulació tan excessius que dificulten i inclús impossibiliten l'execució d'anàlisi d'optimització

[ES] En general, los modelos informáticos son construidos para representar una realidad cuya complejidad imposibilita su análisis analítico. En el caso particular de las redes de distribución de agua, constituyen una potente herramienta de obtención de información útil para la toma de decisiones relacionadas con la operación de la red y la gestión del recurso. El problema surge cuando, en la búsqueda de aumentar la fiabilidad, suelen incorporarse gran parte de los elementos constitutivos de las redes, incluso aquellos que podrían ser considerados prescindibles. Esto conlleva a la obtención de modelos de distribución muy completos que si bien cumplen la función de emular correctamente la realidad que representan, suelen tornarse demasiado complejos para ciertos tipos de análisis cuando la red posee dimensiones topológicas de gran magnitud. Un caso particular de lo mencionado son los modelos de operación y monitoreo de redes de abastecimiento en tiempo real. Estos sistemas deben ser lo suficientemente sencillos como para poder interpretar fácilmente los fenómenos que ocurren en el sistema. Otro caso común es el análisis de sustitución de tuberías para mejorar el funcionamiento de la red, muy utilizado por las empresas abastecedoras en su búsqueda por encontrar la forma más eficiente de invertir el dinero disponible para rehabilitación. En ambos casos, el trabajo se realiza con programas informáticos que ejecutan numerosas simulaciones variando diferentes parámetros topológicos e hidráulicos que conseguir la solución óptima que cumpla los criterios de cálculo prefijados. Evidentemente, la rapidez con que se ejecuta el algoritmo está directamente relacionada con las características topológicas de la red: a mayor complejidad y tamaño, mayor es el tiempo empleado. A partir de lo anterior, surge la necesidad de realizar simplificaciones en aquellas infraestructuras cuyas dimensiones generan tiempos de simulación tan excesivos que dificultan e incluso imposibilitan la ejecu, [EN] In general, computer models are built to represent a reality whose complexity makes analytical analysis impossible. In the particular case of water distribution networks, they constitute a powerful tool for obtaining useful information for making decisions related to the operation of the network and the management of the resource. The problem arises when, in the search to increase reliability, a large part of the constituent elements of the networks are usually incorporated, even those that could be considered expendable. This leads to obtaining very complete distribution models that, although they fulfill the function of correctly emulating the reality they represent, tend to become too complex for certain types of analysis when the network has large topological dimensions. A particular case of the aforementioned are the models of operation and monitoring of supply networks in real time. These systems must be simple enough to be able to easily interpret the phenomena that occur in the system. Another common case is the analysis of pipe substitution to improve the operation of the network, widely used by supply companies in their search to find the most efficient way to invest the money available for rehabilitation. In both cases, the work is carried out with computer programs that run numerous simulations varying different topological and hydraulic parameters to achieve the optimal solution that meets the predetermined calculation criteria. Obviously, the speed with which the algorithm is executed is directly related to the topological characteristics of the network: the greater the complexity and size, the greater the time taken. From the above, the need arises to carry out simplifications in those infrastructures whose dimensions generate simulation times so excessive that they make it difficult or even impossible to execute optimization analyzes. This simplification must be done using strict topological and hydraulic criteria, since the results obtained in, [CA] En general, els models informàtics són construïts per a representar una realitat la complexitat de la qual impossibilita la seua anàlisi analítica. En el cas particular de les xarxes de distribució d'aigua, constituïxen una potent ferramenta d'obtenció d'informació útil per a la presa de decisions relacionades amb l'operació de la xarxa i la gestió del recurs. El problema sorgix quan, en la busca d'augmentar la fiabilitat, solen incorporar-se gran part dels elements constitutius de les xarxes, inclús aquells que podrien ser considerats prescindibles. Açò comporta a l'obtenció de models de distribució molt complets que si bé complixen la funció d'emular correctament la realitat que representen, solen tornar-se massa complexos per a certs tipus d'anàlisi quan la xarxa posseïx dimensions topològiques de gran magnitud. Un cas particular d'allò que s'ha mencionat són els models d'operació i monitoreo de xarxes d'abastiment en temps real. Estos sistemes han de ser prou senzills com per a poder interpretar fàcilment els fenòmens que ocorren en el sistema. Un altre cas comuna és l'anàlisi de substitució de canonades per a millorar el funcionament de la xarxa, molt utilitzat per les empreses abastidores en la seua busca per trobar la forma més eficient d'invertir els diners disponibles per a rehabilitació. En ambdós casos, el treball es realitza amb programes informàtics que executen nombroses simulacions variant diferents paràmetres topològics i hidràulics que aconseguir la solució òptima que complisca els criteris de càlcul prefixats. Evidentment, la rapidesa amb què s'executa l'algoritme està directament relacionada amb les característiques topològiques de la xarxa: a major complexitat i grandària, major és el temps empleat. A partir de l'anterior, sorgix la necessitat de realitzar simplificacions en aquelles infraestructures les dimensions de les quals generen temps de simulació tan excessius que dificulten i inclús impossibiliten l'execució d'anàlisi d'optimització

In the context of biomarker discovery and molecular characterization of diseases, laser capture microdissection is a highly effective approach to extract disease-specific regions from complex, heterogeneous tissue samples. These regions have to be decomposed into feasible fragments as they have to satisfy certain constraints in size and morphology for the extraction to be successful. We model this problem of constrained shape decomposition as the computation of optimal feasible decompositions of simple polygons. We use a skeleton-based approach and present an algorithmic framework that allows the implementation of various feasibility criteria as well as optimization goals. Motivated by our application, we consider different constraints and examine the resulting fragmentations. Furthermore, we apply our method to lung tissue samples and show its advantages in comparison to a heuristic decomposition approach.

Topology optimization using gradient search with negative and positive elliptical masks and honeycomb tessellation is presented. Through a novel skeletonization algorithm for topologies defined using filled and void hexagonal cells/elements, explicit minimum and maximum length scales are imposed on solid states in the solutions. An analytical example is presented suggesting that for a skeletonized topology, optimal solutions may not always exist for any specified volume fraction, minimum and maximum length scales, and that there may exist implicit interdependence between them. A sequence for length scale (SLS) methodology is proposed wherein solutions are sought by specifying only the minimum and maximum length scales with volume fraction getting determined within a specified range systematically. Through four benchmark problems in small deformation topology optimization, it is demonstrated that solutions by-and-large satisfy the length scale constraints though the latter may get violated at certain local sites. The proposed approach seems promising, noting especially that solutions, if rendered perfectly black and white with minimum length scale explicitly imposed and boundaries smoothened, are quite close in performance compared with the parent topologies. Attaining volume-distributed topologies, wherein members are more or less of the same thickness, may also be possible with the proposed approach.

Identifying local thickness information of fibrous or highly porous structures is challenging. The analysis of tomography data calls for computationally fast, robust, and accurate algorithms. This work systematically investigates systematic errors in the thickness computation and the impact of observed deviations on the predicted mechanical properties using a set of 16 model structures with varying ligament shape and solid fraction. Strongly concave, cylindrical, and convex shaped ligaments organized in a diamond structure are analyzed. The predicted macroscopic mechanical properties represent a highly sensitive measure for systematic errors in the computed geometry. Therefore, the quality of proposed correction methods is assessed via FEM beam models that can be automatically generated from the measured data and allow an efficient prediction of the mechanical properties. The results show that low voxel resolutions can lead to an overprediction of up to 30% in the Young's modulus. A model scanned with a resolution of 200 voxels per unit cell edge (8M voxels) reaches an accuracy of a few percent. Analyzing models of this resolution with the Euclidean distance transformation showed an underprediction of up to 20% for highly concave shapes whereas cylindrical and slightly convex shapes are determined at high accuracy. For the Thickness algorithm, the Young's modulus and yield strength are overpredicted by up to 100% for highly concave ligament shapes. A proposed Smallest Ellipse approach corrects the Thickness data and reduces this error to 20%. It can be used as input for a further robust correction of the Thickness data using an artificial neural network. This approach is highly accurate with remnant errors in the predicted mechanical properties of only a few percent. Furthermore, the data from the FEM beam models are compared to results from FEM solid models providing deeper insights toward further developments on nodal corrections for FEM beam models. As expected

[EN] The problem presented in this edition of the Battle of the Water Networks is to define district metering areas (DMAs) in a large network. The problem is addressed in two phases. First, the complexity of the network is simplified by dividing it into three operational areas. Second, an optimization algorithm defines DMAs, looking for the best feasible solution. A preliminary simulation of the network is made. From this, engineering judgment allows for defining an initial set of elements suitable to change. In the second stage, a heuristic algorithm is used to search for the best DMA definition by selecting the locations and settings of the pressure-reducing valves and isolation valves. The network is then divided into two categories: the main pipes and the distribution pipes. Only the distribution pipes can be closed. With these restrictions and those described in the problem, the algorithm looks for the best DMA definition based on both the pressure and demand distribution among all the DMAs.

[EN] The problem presented in this edition of the Battle of the Water Networks is to define district metering areas (DMAs) in a large network. The problem is addressed in two phases. First, the complexity of the network is simplified by dividing it into three operational areas. Second, an optimization algorithm defines DMAs, looking for the best feasible solution. A preliminary simulation of the network is made. From this, engineering judgment allows for defining an initial set of elements suitable to change. In the second stage, a heuristic algorithm is used to search for the best DMA definition by selecting the locations and settings of the pressure-reducing valves and isolation valves. The network is then divided into two categories: the main pipes and the distribution pipes. Only the distribution pipes can be closed. With these restrictions and those described in the problem, the algorithm looks for the best DMA definition based on both the pressure and demand distribution among all the DMAs.

Various modeling approaches simplify and parametrize the complex network structure of nanoporous gold (NPG) for studying the structure–property relationship based on artificially generated structures. This paper presents a computational efficient and versatile finite element method (FEM) beam model that is based on skeletonization and diameter information derived from the original 3D focused ion beam-scanning electron microscope (FIB-SEM) tomography data of NPG. The geometrical skeleton network is thoroughly examined for a better understanding of the NPG structure. A skeleton FEM beam model is derived that can predict the macroscopic mechanical behavior of the material. Comparisons between the mechanical response of this skeleton beam model and a solid FEM model are conducted. Results showed that the biggest-sphere diameter algorithm implemented in the open-source software FIJI, commonly used for geometrical analysis of microstructural data, overestimates the diameter of the curved NPG ligaments. The larger diameters lead to a significant overestimation of macroscopic stiffness and strength by the skeleton FEM beam model. For a parabolic shaped ligament with only 20% variation in its diameter, a factor of more than two was found in stiffness. It is concluded that improved algorithms for image processing are needed that provide accurate diameter information along the ligament axis.

[EN] A mathematical model is a powerful tool for simulating different scenarios that occur in a water distribution network without making physical experimentation. According to the objectives, a model can be classified into three categories: layout, design and operation. Furthermore, the level of detail is strongly related to the objective that the model tries to achieve. However, bigger amount of information does not mean better accuracy. For example, a fully detailed mathematical model of the network would lead to know every single connection. Usually, this information is so difficult to compile as imprecise. Therefore, one of the most important stages in elaborating a model consists of the model simplification, also known as skeletonization. During the works made for model skeletonization some assumptions are made. Most of the times, these assumptions may produce significant errors. Among the different techniques for network skeletonization, series pipe removal is one of the most used. It consists of replacing several adjacent pipes with a single one which must present the same head losses than the pipes being substituted. When there are no intermediate consumptions the problem has been effectively solved. The problem arises when a demand appears in one of the pipes being removed. It has been demonstrated that methods which assume constant roughness coefficients (either Hazen-Williams or Darcy equations) produce errors in the head losses. These errors may be even higher if travel time is included as a restriction, for example in water quality models. This paper reviews the most common techniques for serial pipes association. The error will be evaluated in both hydraulic and quality models. Finally, a method for exact substitution of serial pipes with intermediate demands is proposed. This method imposes two restrictions (head losses and travel time) and gives exact results when the flow direction is known. The method is tested with an example that highlights the

[EN] A mathematical model is a powerful tool for simulating different scenarios that occur in a water distribution network without making physical experimentation. According to the objectives, a model can be classified into three categories: layout, design and operation. Furthermore, the level of detail is strongly related to the objective that the model tries to achieve. However, bigger amount of information does not mean better accuracy. For example, a fully detailed mathematical model of the network would lead to know every single connection. Usually, this information is so difficult to compile as imprecise. Therefore, one of the most important stages in elaborating a model consists of the model simplification, also known as skeletonization. During the works made for model skeletonization some assumptions are made. Most of the times, these assumptions may produce significant errors. Among the different techniques for network skeletonization, series pipe removal is one of the most used. It consists of replacing several adjacent pipes with a single one which must present the same head losses than the pipes being substituted. When there are no intermediate consumptions the problem has been effectively solved. The problem arises when a demand appears in one of the pipes being removed. It has been demonstrated that methods which assume constant roughness coefficients (either Hazen-Williams or Darcy equations) produce errors in the head losses. These errors may be even higher if travel time is included as a restriction, for example in water quality models. This paper reviews the most common techniques for serial pipes association. The error will be evaluated in both hydraulic and quality models. Finally, a method for exact substitution of serial pipes with intermediate demands is proposed. This method imposes two restrictions (head losses and travel time) and gives exact results when the flow direction is known. The method is tested with an example that highlights the

Skeletonization provides an effective and compact representation of objects, which is useful for object description, retrieval, manipulation, matching, registration, tracking, recognition, and compression. It also facilitates efficient assessment of local object properties, e.g., scale, orientation, topology, etc. Several computational approaches are available in literature toward extracting the skeleton of an object, some of which are widely different in terms of their principles. In this paper, we present a comprehensive and concise survey of different skeletonization algorithms and discuss their principles, challenges, and benefits. Topology preservation, parallelization, and multi-scale skeletonization approaches are discussed. Finally, various applications of skeletonization are reviewed and the fundamental challenges of assessing the performance of different skeletonization algorithms are discussed.

This paper describes a new algorithm which enable efficient conversion of graphical representation of warehouse into graph theory representation and consequently accelerates estimation for route costs. The proposed algorithm computes route distances between any place in warehouses and does so significantly faster than traditional approaches. For this purpose an algorithm based on Breadth first search, image processing “skeletonization” and Dijkstra algorithm was proposed. Using the proposed algorithm it is possible to search routes in a warehouse effectively and fast using precomputed routing table. Searching time is approximately hundreds of microseconds using routing table and even it is independent on size of warehouse instead of using Dijkstra algorithm.

This paper describes a new algorithm which enable efficient conversion of graphical representation of warehouse into graph theory representation and consequently accelerates estimation for route costs. The proposed algorithm computes route distances between any place in warehouses and does so significantly faster than traditional approaches. For this purpose an algorithm based on Breadth first search, image processing “skeletonization” and Dijkstra algorithm was proposed. Using the proposed algorithm it is possible to search routes in a warehouse effectively and fast using precomputed routing table. Searching time is approximately hundreds of microseconds using routing table and even it is independent on size of warehouse instead of using Dijkstra algorithm.

This paper describes a new algorithm which enable efficient conversion of graphical representation of warehouse into graph theory representation and consequently accelerates estimation for route costs. The proposed algorithm computes route distances between any place in warehouses and does so significantly faster than traditional approaches. For this purpose an algorithm based on Breadth first search, image processing “skeletonization” and Dijkstra algorithm was proposed. Using the proposed algorithm it is possible to search routes in a warehouse effectively and fast using precomputed routing table. Searching time is approximately hundreds of microseconds using routing table and even it is independent on size of warehouse instead of using Dijkstra algorithm.

This paper describes a new algorithm which enable efficient conversion of graphical representation of warehouse into graph theory representation and consequently accelerates estimation for route costs. The proposed algorithm computes route distances between any place in warehouses and does so significantly faster than traditional approaches. For this purpose an algorithm based on Breadth first search, image processing “skeletonization” and Dijkstra algorithm was proposed. Using the proposed algorithm it is possible to search routes in a warehouse effectively and fast using precomputed routing table. Searching time is approximately hundreds of microseconds using routing table and even it is independent on size of warehouse instead of using Dijkstra algorithm.

This paper describes a new algorithm which enable efficient conversion of graphical representation of warehouse into graph theory representation and consequently accelerates estimation for route costs. The proposed algorithm computes route distances between any place in warehouses and does so significantly faster than traditional approaches. For this purpose an algorithm based on Breadth first search, image processing “skeletonization” and Dijkstra algorithm was proposed. Using the proposed algorithm it is possible to search routes in a warehouse effectively and fast using precomputed routing table. Searching time is approximately hundreds of microseconds using routing table and even it is independent on size of warehouse instead of using Dijkstra algorithm.

An improved method for authenticating users on specific points of the fingerprint, thus improving the speed and efficiency of the recognition procedure. The method uses information about the coordinates of three points and the angle between adjacent points of the triplet. Software system for automated system users authentication for visualizing the results of the research where designed., У статті запропоновано вдосконалений метод аутентифікації користувачів за особливими точками відбитка пальця, що дозволило підвищити швидкість та ефективність процедури розпізнавання. Метод використовує дані про координати трьох точок та кут між сусідніми точками триплета. Розроблено програмний комплекс аутентифікації користувачів автоматизованої системи для візуалізації результатів проведених досліджень.

An improved method for authenticating users on specific points of the fingerprint, thus improving the speed and efficiency of the recognition procedure. The method uses information about the coordinates of three points and the angle between adjacent points of the triplet. Software system for automated system users authentication for visualizing the results of the research where designed., У статті запропоновано вдосконалений метод аутентифікації користувачів за особливими точками відбитка пальця, що дозволило підвищити швидкість та ефективність процедури розпізнавання. Метод використовує дані про координати трьох точок та кут між сусідніми точками триплета. Розроблено програмний комплекс аутентифікації користувачів автоматизованої системи для візуалізації результатів проведених досліджень.

An improved method for authenticating users on specific points of the fingerprint, thus improving the speed and efficiency of the recognition procedure. The method uses information about the coordinates of three points and the angle between adjacent points of the triplet. Software system for automated system users authentication for visualizing the results of the research where designed., У статті запропоновано вдосконалений метод аутентифікації користувачів за особливими точками відбитка пальця, що дозволило підвищити швидкість та ефективність процедури розпізнавання. Метод використовує дані про координати трьох точок та кут між сусідніми точками триплета. Розроблено програмний комплекс аутентифікації користувачів автоматизованої системи для візуалізації результатів проведених досліджень.

An improved method for authenticating users on specific points of the fingerprint, thus improving the speed and efficiency of the recognition procedure. The method uses information about the coordinates of three points and the angle between adjacent points of the triplet. Software system for automated system users authentication for visualizing the results of the research where designed., У статті запропоновано вдосконалений метод аутентифікації користувачів за особливими точками відбитка пальця, що дозволило підвищити швидкість та ефективність процедури розпізнавання. Метод використовує дані про координати трьох точок та кут між сусідніми точками триплета. Розроблено програмний комплекс аутентифікації користувачів автоматизованої системи для візуалізації результатів проведених досліджень.

Digital topology and geometry refers to the use of topologic and geometric properties and features for images defined in digital grids. Such methods have been widely used in many medical imaging applications, including image segmentation, visualization, manipulation, interpolation, registration, surface-tracking, object representation, correction, quantitative morphometry etc. Digital topology and geometry play important roles in medical imaging research by enriching the scope of target outcomes and by adding strong theoretical foundations with enhanced stability, fidelity, and efficiency. This paper presents a comprehensive yet compact survey on results, principles, and insights of methods related to digital topology and geometry with strong emphasis on understanding their roles in various medical imaging applications. Specifically, this paper reviews methods related to distance analysis and path propagation, connectivity, surface-tracking, image segmentation, boundary and centerline detection, topology preservation and local topological properties, skeletonization, and object representation, correction, and quantitative morphometry. A common thread among the topics reviewed in this paper is that their theory and algorithms use the principle of digital path connectivity, path propagation, and neighborhood analysis.

This paper presents a practical and robust approach for upright human curve-skeleton extraction. Curve skeletons are object descriptors that represent a simplified version of the geometry and topology of a 3-D object. The curve-skeleton of a human-scanned point set enables the approximation of the underlying skeletal structure and thus, to estimate the body configuration (human pose). In contrast to most curve-skeleton extraction methodologies from the literature, we herein propose a real-time curve-skeleton extraction approach that applies to scanned point clouds, independently of the object’s complexity and/or the amount of noise within the depth measurements. The experimental results show the ability of the algorithm to extract a centered curve-skeleton within the 3-D object, with the same topology, and with unit thickness. The proposed approach is intended for real world applications and hence, it handles large portions of data missing due to occlusions, acquisition hindrances or registration inaccuracies.

This paper presents a practical and robust approach for upright human curve-skeleton extraction. Curve skeletons are object descriptors that represent a simplified version of the geometry and topology of a 3-D object. The curve-skeleton of a human-scanned point set enables the approximation of the underlying skeletal structure and thus, to estimate the body configuration (human pose). In contrast to most curve-skeleton extraction methodologies from the literature, we herein propose a real-time curve-skeleton extraction approach that applies to scanned point clouds, independently of the object’s complexity and/or the amount of noise within the depth measurements. The experimental results show the ability of the algorithm to extract a centered curve-skeleton within the 3-D object, with the same topology, and with unit thickness. The proposed approach is intended for real world applications and hence, it handles large portions of data missing due to occlusions, acquisition hindrances or registration inaccuracies.

[EN] Water distribution networks were included in the catalogue of critical infrastructures by different institutions as the European Council. One of the vulnerabilities of a water distribution networks consists of the contamination due to accidental or provoked events. Therefore, it is increasingly common to develop water quality models which allow the study of these threats. Many hydraulic models use algorithms with a high computational cost. Therefore, any strategy to accelerate these algorithms is an important contribution to the problem. This paper proposes a method to simplify branched areas of the network without losing information regarding water quality.

[EN] Water distribution networks were included in the catalogue of critical infrastructures by different institutions as the European Council. One of the vulnerabilities of a water distribution networks consists of the contamination due to accidental or provoked events. Therefore, it is increasingly common to develop water quality models which allow the study of these threats. Many hydraulic models use algorithms with a high computational cost. Therefore, any strategy to accelerate these algorithms is an important contribution to the problem. This paper proposes a method to simplify branched areas of the network without losing information regarding water quality.

This paper presents a surface and solid voxelization approach for incomplete point cloud datasets. Voxelization stands for a discrete approximation of 3-D objects into a volumetric representation, a process which is commonly employed in computer graphics and increasingly being used in computer vision. In contrast to surface voxelization, solid voxelization not only set those voxels related to the object surface but also those voxels considered to be inside the object. To that end, we first approximate the given point set, usually describing the external object surface, to an axis-aligned voxel grid. Then, we slice-wise construct a shell containing all surface voxels along each grid-axis pair. Finally, voxels inside the constructed shell are set. Solid voxelization results from the combination of all slices, resulting in a watertight and gap-free representation of the object. The experimental results show a high performance when voxelizing point cloud datasets, independently of the object’s complexity, robust to noise, and handling large portions of data missing.

Establishing meaningful relationships between cellular structure and function requires accurate morphological reconstructions. In particular, there is an unmet need for high quality surface reconstructions to model subcellular and synaptic interactions among neurons and glia at nanometer resolution. We address this need with VolRoverN, a software package that produces accurate, efficient, and automated 3D surface reconstructions from stacked 2D contour tracings. While many techniques and tools have been developed in the past for 3D visualization of cellular structure, the reconstructions from VolRoverN meet specific quality criteria that are important for dynamical simulations. These criteria include manifoldness, water-tightness, lack of self- and object-object-intersections, and geometric accuracy. These enhanced surface reconstructions are readily extensible to any cell type and are used here on spiny dendrites with complex morphology and axons from mature rat hippocampal area CA1. Both spatially realistic surface reconstructions and reduced skeletonizations are produced and formatted by VolRoverN for easy input into analysis software packages for neurophysiological simulations at multiple spatial and temporal scales ranging from ion electro-diffusion to electrical cable models.

This paper presents a surface and solid voxelization approach for incomplete point cloud datasets. Voxelization stands for a discrete approximation of 3-D objects into a volumetric representation, a process which is commonly employed in computer graphics and increasingly being used in computer vision. In contrast to surface voxelization, solid voxelization not only set those voxels related to the object surface but also those voxels considered to be inside the object. To that end, we first approximate the given point set, usually describing the external object surface, to an axis-aligned voxel grid. Then, we slice-wise construct a shell containing all surface voxels along each grid-axis pair. Finally, voxels inside the constructed shell are set. Solid voxelization results from the combination of all slices, resulting in a watertight and gap-free representation of the object. The experimental results show a high performance when voxelizing point cloud datasets, independently of the object's complexity, robust to noise, and handling large portions of data missing. © 2014 IEEE.

This paper presents a surface and solid voxelization approach for incomplete point cloud datasets. Voxelization stands for a discrete approximation of 3-D objects into a volumetric representation, a process which is commonly employed in computer graphics and increasingly being used in computer vision. In contrast to surface voxelization, solid voxelization not only set those voxels related to the object surface but also those voxels considered to be inside the object. To that end, we first approximate the given point set, usually describing the external object surface, to an axis-aligned voxel grid. Then, we slice-wise construct a shell containing all surface voxels along each grid-axis pair. Finally, voxels inside the constructed shell are set. Solid voxelization results from the combination of all slices, resulting in a watertight and gap-free representation of the object. The experimental results show a high performance when voxelizing point cloud datasets, independently of the object's complexity, robust to noise, and handling large portions of data missing. © 2014 IEEE.

This paper presents a surface and solid voxelization approach for incomplete point cloud datasets. Voxelization stands for a discrete approximation of 3-D objects into a volumetric representation, a process which is commonly employed in computer graphics and increasingly being used in computer vision. In contrast to surface voxelization, solid voxelization not only set those voxels related to the object surface but also those voxels considered to be inside the object. To that end, we first approximate the given point set, usually describing the external object surface, to an axis-aligned voxel grid. Then, we slice-wise construct a shell containing all surface voxels along each grid-axis pair. Finally, voxels inside the constructed shell are set. Solid voxelization results from the combination of all slices, resulting in a watertight and gap-free representation of the object. The experimental results show a high performance when voxelizing point cloud datasets, independently of the object’s complexity, robust to noise, and handling large portions of data missing.

Se plantea la optimización económica de la red de abastecimiento del Campo de Murcia, la cual es gestionada por la Empresa Municipal de Aguas y Saneamiento de Murcia (EMUASA). Para ello se debe encontrar el conjunto de maniobras que minimizan el coste energético relacionado con la operación del sistema. Un esquema en detalle representativo de la red es presentado en EPANET, el cual contiene 2363 nodos, 2599 tuberías, 9 depósitos, 2 puntos de alimentación, 28 válvulas y 9 equipos de bombeo con controles asociados a su funcionamiento. El proceso de optimización de la red es dividió en dos grandes etapas, la primera de ellas considera técnicas de equeletización para poder genera un modelo de análisis reducido de la red. El modelo que se ha obtenido cuenta con 65 nodos de consumo, 59 tuberías y 8 válvulas, manteniendo el número de equipos de bombeo y depósitos en la red. Con esto una reducción del 98% de los elementos es alcanzada, manteniendo además un alto grado de similitud en el comportamiento hidráulico del sistema y reduciendo los tiempos de cálculo en un 92%. La segunda etapa del proyecto contempla la utilización del software HOLORED, herramienta de optimización diseñada por el Departamento de Ingeniería Hidráulica y Medio Ambiente de la Universidad Politécnica de Valencia. HOLORED utiliza una base optimizadora inspirada en los algoritmos genéticos, creando soluciones a partir de cadenas que contienen las diferentes variables de cada elemento de la red. Durante el transcurso de la optimización, una evolución de las soluciones ocurre gracias a procesos de cruzamiento y mutación de estas cadenas. Dichos procesos permiten la generación de nuevas cadenas que aportaran diferentes soluciones en la búsqueda de un óptimo. Una vez se alcance un punto de optimización deseado según un parámetro establecido se acepta que la solución encontrada es óptima. Como resultado a este proceso de optimización, se presentan: controles de operación en equipos de bombeo, nivel óptimo ini

Se plantea la optimización económica de la red de abastecimiento del Campo de Murcia, la cual es gestionada por la Empresa Municipal de Aguas y Saneamiento de Murcia (EMUASA). Para ello se debe encontrar el conjunto de maniobras que minimizan el coste energético relacionado con la operación del sistema. Un esquema en detalle representativo de la red es presentado en EPANET, el cual contiene 2363 nodos, 2599 tuberías, 9 depósitos, 2 puntos de alimentación, 28 válvulas y 9 equipos de bombeo con controles asociados a su funcionamiento. El proceso de optimización de la red es dividió en dos grandes etapas, la primera de ellas considera técnicas de equeletización para poder genera un modelo de análisis reducido de la red. El modelo que se ha obtenido cuenta con 65 nodos de consumo, 59 tuberías y 8 válvulas, manteniendo el número de equipos de bombeo y depósitos en la red. Con esto una reducción del 98% de los elementos es alcanzada, manteniendo además un alto grado de similitud en el comportamiento hidráulico del sistema y reduciendo los tiempos de cálculo en un 92%. La segunda etapa del proyecto contempla la utilización del software HOLORED, herramienta de optimización diseñada por el Departamento de Ingeniería Hidráulica y Medio Ambiente de la Universidad Politécnica de Valencia. HOLORED utiliza una base optimizadora inspirada en los algoritmos genéticos, creando soluciones a partir de cadenas que contienen las diferentes variables de cada elemento de la red. Durante el transcurso de la optimización, una evolución de las soluciones ocurre gracias a procesos de cruzamiento y mutación de estas cadenas. Dichos procesos permiten la generación de nuevas cadenas que aportaran diferentes soluciones en la búsqueda de un óptimo. Una vez se alcance un punto de optimización deseado según un parámetro establecido se acepta que la solución encontrada es óptima. Como resultado a este proceso de optimización, se presentan: controles de operación en equipos de bombeo, nivel óptimo ini

Se plantea la optimización económica de la red de abastecimiento del Campo de Murcia, la cual es gestionada por la Empresa Municipal de Aguas y Saneamiento de Murcia (EMUASA). Para ello se debe encontrar el conjunto de maniobras que minimizan el coste energético relacionado con la operación del sistema. Un esquema en detalle representativo de la red es presentado en EPANET, el cual contiene 2363 nodos, 2599 tuberías, 9 depósitos, 2 puntos de alimentación, 28 válvulas y 9 equipos de bombeo con controles asociados a su funcionamiento. El proceso de optimización de la red es dividió en dos grandes etapas, la primera de ellas considera técnicas de equeletización para poder genera un modelo de análisis reducido de la red. El modelo que se ha obtenido cuenta con 65 nodos de consumo, 59 tuberías y 8 válvulas, manteniendo el número de equipos de bombeo y depósitos en la red. Con esto una reducción del 98% de los elementos es alcanzada, manteniendo además un alto grado de similitud en el comportamiento hidráulico del sistema y reduciendo los tiempos de cálculo en un 92%. La segunda etapa del proyecto contempla la utilización del software HOLORED, herramienta de optimización diseñada por el Departamento de Ingeniería Hidráulica y Medio Ambiente de la Universidad Politécnica de Valencia. HOLORED utiliza una base optimizadora inspirada en los algoritmos genéticos, creando soluciones a partir de cadenas que contienen las diferentes variables de cada elemento de la red. Durante el transcurso de la optimización, una evolución de las soluciones ocurre gracias a procesos de cruzamiento y mutación de estas cadenas. Dichos procesos permiten la generación de nuevas cadenas que aportaran diferentes soluciones en la búsqueda de un óptimo. Una vez se alcance un punto de optimización deseado según un parámetro establecido se acepta que la solución encontrada es óptima. Como resultado a este proceso de optimización, se presentan: controles de operación en equipos de bombeo, nivel óptimo ini

Terrestrial laser scanners capture 3D geometry of real world objects as a point cloud. This paper reports on a new algorithm developed for the skeletonization of a laser scanner point cloud. The skeletonization algorithm proposed in this paper consists of three steps: (i) extraction of a graph from an octree organization, (ii) reduction of the graph to a skeleton, and (iii) embedding of the skeleton into the point cloud. For these three steps, only one input parameter is required. The results are validated on laser scanner point clouds representing 2 classes of objects; first on botanic trees as a special application and secondly on popular arbitrary objects. The presented skeleton found its first application in obtaining botanic tree parameters like length and diameter of branches and is presented here in a new, generalized version. Its definition as Reeb Graph, proofs the usefulness of the skeleton for applications like shape analysis. In this paper we show that the resulting skeleton contains the Reeb Graph and investigate the practically relevant parameters: centeredness and topological correctness. The robustness of this skeletonization method against undersampling, varying point density and systematic errors of the point cloud is demonstrated on real data examples., Remote Sensing, Aerospace Engineering

Terrestrial laser scanners capture 3D geometry of real world objects as a point cloud. This paper reports on a new algorithm developed for the skeletonization of a laser scanner point cloud. The skeletonization algorithm proposed in this paper consists of three steps: (i) extraction of a graph from an octree organization, (ii) reduction of the graph to a skeleton, and (iii) embedding of the skeleton into the point cloud. For these three steps, only one input parameter is required. The results are validated on laser scanner point clouds representing 2 classes of objects; first on botanic trees as a special application and secondly on popular arbitrary objects. The presented skeleton found its first application in obtaining botanic tree parameters like length and diameter of branches and is presented here in a new, generalized version. Its definition as Reeb Graph, proofs the usefulness of the skeleton for applications like shape analysis. In this paper we show that the resulting skeleton contains the Reeb Graph and investigate the practically relevant parameters: centeredness and topological correctness. The robustness of this skeletonization method against undersampling, varying point density and systematic errors of the point cloud is demonstrated on real data examples., Remote Sensing, Aerospace Engineering

In the animation process of a human-like 3D model, a skeleton must be specified to define the model’s surface deformation of its limbs. Nowadays the skeleton specification is hand made and very time consuming task. In this paper we propose a novel semi-automatic method for rigging a 3D model in an arbitrary pose using a skeleton defined in an animation datafile with no specific initial pose. First a skeleton is extracted from the voxelizated model, this skeleton is refined and transformed into a tree-data structure. Because the 3D model can be in an arbitrary pose, user interaction is required to select the five limbs correspondence (head, hands and feet), and finally a skeleton taken from an animation data file or a external source is adjusted to the geometric skeleton., Peer Reviewed, Postprint (published version)

We introduce a new class of numerical schemes for the solution of the Cauchy problem for non-stiff ordinary differential equations (ODEs). Our algorithms are of the predictor-corrector type; they are obtained via the decomposition of the solutions of the ODEs into combinations of appropriately chosen exponentials, whereas the classical schemes are based on the approximation of solutions by polynomials. The resulting schemes have the advantage of significantly faster convergence, given fixed lengths of predictor and corrector vectors. The performance of the approach is illustrated via a number of numerical examples., Sponsored in part by the Air Force Office of Scientific Research Contract No. FA9550-06-1-0239.

We propose a new segmentation algorithm based on competing fuzzy connectedness theory, which is then used for visualizing coronary arteries in 3D CT angiography (CTA) images. The major difference compared to other fuzzy connectedness algorithms is that an additional data structure, the connectedness tree, is constructed at the same time as the seeds propagate. In preliminary evaluations, accurate result have been achieved with very limited user interaction. In addition to improving computational speed and segmentation results, the fuzzy connectedness tree algorithm also includes automated extraction of the vessel centerlines, which is a promising approach for creating curved plane reformat (CPR) images along arteries’ long axes., QC 20191030

In the past years the so-called body-centered cubic grid (bcc) has been examined and proved to be superior over Cartesian lattices for certain applications. Our work deals with parallel thinning on these bcc grids. We introduce conditions which are sufficient for retaining topology and suggest additional conditions to influence the shape of the resulting skeleton. We further developed an algorithm to extract curve skeletons out of 3d objects in parallel which we also present here. We show in our results that the developed thinning approach on bcc grids is extremely efficient.