3,255 research outputs found

    An SEM-DSM three-dimensional hybrid method for modelling teleseismic waves with complicated source-side structures

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    Despite recent advances in High Performance Computing (HPC), numerical simulation of high frequency (e.g. 1 Hz or higher) seismic wave propagation at the global scale is still prohibitive. To overcome this difficulty, we propose a hybrid method to efficiently compute teleseismic waveforms with 3-D source-side structures. By coupling the Spectral Element Method (SEM) with the Direct Solution Method (DSM) based on the representation theorem, we are able to limit the costly SEM simulation to a small source-side region and avoid computation over the entire space of the Earth. Our hybrid method is benchmarked against 1-D DSM synthetics and 3-D SEM synthetics. We also discuss numerical difficulties in the implementation, including slow DSM convergence near source depth, discretization error, Green’s function interpolation and local 3-D wavefield approximations. As a case study, we apply our hybrid method to two subduction earthquakes and show its advantage in understanding 3-D source-side effects on teleseismic P-waves. Our hybrid method reduces computational cost by more than two orders of magnitude when only source-side 3-D complexities are of concern. Thus our hybrid method is useful for a series of problems in seismology, such as imaging 3-D structures of a subducting slab or a mid-ocean ridge and studying source parameters with 3-D source-side complexities using teleseismic waveforms

    Development of GIS as an information management system: a case study for the Burden Center

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    For a park site, it is very important and necessary to let the local planning authorities realize and understand the important aspects and benefits of the site and to establish the long-range development strategies for the location. In order to succeed during the planning process, the communication and information that flow among all the participants must be well organized. In this situation, a project-wide Geographic Information System (GIS) would be a good solution. The goal of this project is to explore the possibilities for administrative authorities to implement a GIS database system to support the site planning and management of a park site. The research is based on three parts: The first involves components related to the field of park planning and GIS technology. It provides an outline of the park planning and management process, GIS techniques, and GIS-based strategies that have been developed for use in park planning and design. The second part provides a method of developing a GIS database prototype for park planning and management. An inventory of existing assets and options for future development can be integrated in a GIS database. Then this provides a platform for the gradual development of a comprehensive park management system. The third part involves the development of a prototypical GIS database design for an existing park site. It represents a practical implementation of a GIS system for the Burden Center, an historical and agricultural research center in Baton Rouge, Louisiana. This system will give quality information about the Burden Center site and will serve as a foundation to facilitate park planning, decision-making, facility management, future development, and resource interpretation for educational purposes

    Ontology based data warehouse modeling and mining of earthquake data: prediction analysis along Eurasian-Australian continental plates

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    Seismological observatories archive volumes of heterogeneous types of earthquake data. These organizations, by virtue of their geographic operations, handle complicated hierarchical data structures. In order to effectively and efficiently perform seismological observatories business activities, the flow of data and information must be consistent and information is shared among its units, situated at differentgeographic locations. In order to improve information sharing among observatories, heterogeneous nature of earthquake data from various sources are intelligently integrated. Data warehouse is a solution, in which, earthquake data entities are modeled using ontology-base multidimensional representation.These data are structured and stored in multi-dimensions in a warehousing environment to minimize the complexity of heterogeneous data. Authors are of the view that data integration process adds value to knowledge building and information sharing among different observatories. Authors suggest that warehoused data modeling facilitates earthquake prediction analysis more effectively

    Integration of BIM in Building Sustainability Assessment methods

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    Tese de doutoramento em Sustentabilidade do Ambiente ConstruídoThe Architecture, Engineering and Construction (AEC) industry is highly responsible for several environmental impacts and worldwide authorities and societies are increasingly looking for more sustainable buildings. Given the ambitious targets of climate neutrality and decarbonisation, there is an urgent need to develop specific strategies to act in the building sector, as it has been recognised as a key industry to reverse environmental impacts. Among the existing tools, Building Sustainability Assessment (BSA) methods stand out as a pathway to evaluate and promote the integration of sustainability principles in buildings. However, such methods often require multi-disciplinary information about the building and significant resources such as time, money, and human labour. Consequently, and in the absence of mandatory legislation, BSA is usually neglected or applied in project later stages just to provide a sustainable evaluation of the building. With the deployment of Building Information Modelling (BIM), the opportunity for BSA to adopt and benefit from BIM functionalities arises. Currently, BIM has not been used comprehensively in the evaluation process of BSA but the potential for process automation and simplification are well known. To effectively integrate BSA into BIM environment, this research aims to develop a BIM integration framework for the Portuguese residential BSA method SBToolPT-H. Moreover, such framework will be materialized by the creation of an enduser BIM-based application – SBToolBIM – which will act as a decision support tool regarding building sustainability for the project's early stages. SBToolBIM will automate and accelerate the assessment of SBToolPTH by reflecting its criteria through computable rules. Results show the attractiveness of SBToolBIM, as well as the possibility to have real-time feedback about the building sustainability level in early project stages, allowing for the introduction and comparison of different sustainability measures with few resources. SBToolBIM has established a novel and common approach which can be used as a systematic framework to apply BIM in other BSA schemes, representing a pathway to reduce the building sector impacts and provide valuable contributes to reach worldwide climate neutrality and decarbonisation targets.A indústria da Arquitetura, Engenharia e Construção (AEC) é responsável por diversos impactes ambientais, levando as autoridades e sociedades mundiais à procura por edifícios mais sustentáveis. Perante os ambiciosos objetivos da neutralidade climática e descarbonização, surge a necessidade de desenvolver estratégias específicas para o setor dos edifícios, dado ser uma indústria chave para a reversão dos referidos impactes. Entre as ferramentas existentes, destacam-se os métodos da avaliação da sustentabilidade de edifícios (BSA, do inglês Building Sustainability Assessment) como forma de avaliar e promover a integração de medidas sustentáveis. No entanto, a sua utilização requer informações multidisciplinares do edifício, bem como recursos significativos, tais como tempo, custos e mão de obra. Consequentemente e na ausência de legislação obrigatória, os BSA são geralmente negligenciados ou aplicados em fases finais de projeto, apenas para identificar o nível de sustentabilidade do edifício. Com a implementação do Building Information Modeling (BIM), surge a oportunidade dos BSA adotarem e beneficiarem das suas funcionalidades. Atualmente, o BIM ainda não é integralmente utilizado no processo de avaliação dos BSA, mas as suas potencialidades para automação e simplificação do processo já foram reconhecidas. De modo a integrar os BSA em ambiente BIM, este trabalho visa desenvolver uma estrutura de integração BIM para o método BSA residencial português SBToolPT-H. A estrutura será materializada através da criação de uma aplicação BIM – SBToolBIM – que irá atuar como uma ferramenta de apoio à decisão em fases iniciais de projeto. O SBToolBIM irá automatizar e acelerar os processos de avaliação da sustentabilidade através do SBToolPT-H, refletindo os seus critérios através de regras computacionais. Os resultados demonstram a utilidade do SBToolBIM, bem como a possibilidade de fornecer feedback em tempo real sobre o nível de sustentabilidade do edifício nas fases iniciais de projeto, permitindo a introdução e a comparação de diferentes medidas de sustentabilidade, utilizando poucos recursos. O SBToolBIM estabelece uma nova abordagem sistemática para aplicação do BIM noutros métodos BSA, representando um caminho para a redução dos impactes do setor e dando valiosas contribuições para alcançar as metas de neutralidade climática e descarbonização.SBToolBIM research was funded by the Portuguese Foundation for Science and Technology (FCT), grant number SFRH/BD/145735/2019

    Three-dimensional interactive maps: theory and practice

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    Example-Based Urban Modeling

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    The manual modeling of virtual cities or suburban regions is an extremely time-consuming task, which expects expert knowledge of different fields. Existing modeling tool-sets have a steep learning curve and may need special education skills to work with them productively. Existing automatic methods rely on rule sets and grammars to generate urban structures; however, their expressiveness is limited by the rule-sets. Expert skills are necessary to typeset rule sets successfully and, in many cases, new rule-sets need to be defined for every new building style or street network style. To enable non-expert users, the possibility to construct urban structures for individual experiments, this work proposes a portfolio of novel example-based synthesis algorithms and applications for the controlled generation of virtual urban environments. The notion example-based denotes here that new virtual urban environments are created by computer programs that re-use existing digitized real-world data serving as templates. The data, i.e., street networks, topography, layouts of building footprints, or even 3D building models, necessary to realize the envisioned task is already publicly available via online services. To enable the reuse of existing urban datasets, novel algorithms need to be developed by encapsulating expert knowledge and thus allow the controlled generation of virtual urban structures from sparse user input. The focus of this work is the automatic generation of three fundamental structures that are common in urban environments: road networks, city block, and individual buildings. In order to achieve this goal, the thesis proposes a portfolio of algorithms that are briefly summarized next. In a theoretical chapter, we propose a general optimization technique that allows formulating example-based synthesis as a general resource-constrained k-shortest path (RCKSP) problem. From an abstract problem specification and a database of exemplars carrying resource attributes, we construct an intermediate graph and employ a path-search optimization technique. This allows determining either the best or the k-best solutions. The resulting algorithm has a reduced complexity for the single constraint case when compared to other graph search-based techniques. For the generation of road networks, two different techniques are proposed. The first algorithm synthesizes a novel road network from user input, i.e., a desired arterial street skeleton, topography map, and a collection of hierarchical fragments extracted from real-world road networks. The algorithm recursively constructs a novel road network reusing these fragments. Candidate fragments are inserted into the current state of the road network, while shape differences will be compensated by warping. The second algorithm synthesizes road networks using generative adversarial networks (GANs), a recently introduced deep learning technique. A pre- and postprocessing pipeline allows using GANs for the generation of road networks. An in-depth evaluation shows that GANs faithfully learn the road structure present in the example network and that graph measures such as area, aspect ratio, and compactness, are maintained within the virtual road networks. To fill empty city blocks in road networks we propose two novel techniques. The first algorithm re-uses real-world city blocks and synthesizes building footprint layouts into empty city blocks by retrieving viable candidate blocks from a database. We evaluate the algorithm and synthesize a multitude of city block layouts reusing real-world building footprint arrangements from European and US-cities. In addition, we increase the realism of the synthesized layouts by performing example-based placement of 3D building models. This technique is evaluated by placing buildings onto challenging footprint layouts using different example building databases. The second algorithm computes a city block layout, resembling the style of a real-world city block. The original footprint layout is deformed to construct a textit{guidance map}, i.e., the original layout is transferred to a target city block using warping. This guidance map and the original footprints are used by an optimization technique that computes a novel footprint layout along the city block edges. We perform a detailed evaluation and show that using the guidance map allows transferring of the original layout, locally as well as globally, even when the source and target shapes drastically differ. To synthesize individual buildings, we use the general optimization technique described first and formulate the building generation process as a resource-constrained optimization problem. From an input database of annotated building parts, an abstract description of the building shape, and the specification of resource constraints such as length, area, or a number of architectural elements, a novel building is synthesized. We evaluate the technique by synthesizing a multitude of challenging buildings fulfilling several global and local resource constraints. Finally, we show how this technique can even be used to synthesize buildings having the shape of city blocks and might also be used to fill empty city blocks in virtual street networks. All algorithms presented in this work were developed to work with a small amount of user input. In most cases, simple sketches and the definition of constraints are enough to produce plausible results. Manual work is necessary to set up the building part databases and to download example data from mapping services available on the Internet
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