93 research outputs found

    ECOHYDROLOGICAL MODELING OF BEAVER DAMS

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    Beavers (Castor canadensis and C. fiber) are expanding in their native range in North America and Eurasia and are expanding their range into urban environments and the Arctic tundra. Outside their natural range, they are also in Southern Patagonia because of historic releases in the fur industry. Given the broad geographical span of this expansion, it is critical to understand and predict the hydrology of beaver-dominated landscapes. Beavers build dams that modify the water balance and modulate streamflow through different flow states, which might result in drought and flood mitigation. To date, four published hydrological models have been developed to predict these impacts; however, these models were unable to represent dam variability and dynamics. In this study, a model specific to beaver dams was developed to predict the impacts of beaver dams on hydrology by including the flow state dynamics and the heterogeneity of dams and ponds. First, through the instrumentation of the montane peatland of Sibbald Fen in the Canadian Rocky Mountains, I determined that flow state changes of beaver dams are dynamic on a much shorter scale than previously documented. The shifts from one flow state to another happen regularly, have limited synchronicity within dam sequences, and can be predicted. In Sibbald, 66% to 80% of the flow state changes coincided with rainfall-runoff triggers and no changes were associated with biota using the dams. Following this flow state dynamic, I then developed an open-source model called BeaverPy in Python to simulate key features of dams and their impact on hydrology. Five single flow states and mixed combinations were included to identify their dynamics using a vector-based modeling approach, which accounted for changes in dam structures. Simulating individual and in-sequence dams from Sibbald Fen demonstrated that BeaverPy successfully models streamflow modulation by beaver dams, water storage in ponds, and flow state changes. Metrics for simulated vs. measured behavior for streamflow showed a good agreement in root mean squared error (g in beaver-dominated environments, thereby enhancing the understanding of how to incorporate beaver dams into flood mitigation and stream restoration projects and climate change initiatives

    GAC-MAC-SGA 2023 Sudbury Meeting: Abstracts, Volume 46

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    Computer Aided Verification

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    This open access two-volume set LNCS 13371 and 13372 constitutes the refereed proceedings of the 34rd International Conference on Computer Aided Verification, CAV 2022, which was held in Haifa, Israel, in August 2022. The 40 full papers presented together with 9 tool papers and 2 case studies were carefully reviewed and selected from 209 submissions. The papers were organized in the following topical sections: Part I: Invited papers; formal methods for probabilistic programs; formal methods for neural networks; software Verification and model checking; hyperproperties and security; formal methods for hardware, cyber-physical, and hybrid systems. Part II: Probabilistic techniques; automata and logic; deductive verification and decision procedures; machine learning; synthesis and concurrency. This is an open access book

    Study of the interactions between snowpack and forest cover in the Aragonese Pyrenees and their eco-hydrological implications

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    En las montañas de latitudes medias los bosques y la nieve constituyen recursos naturales prioritarios, tanto desde el punto de vista medioambiental como del económico. Los Pirineos no son una excepción, dado que en esta cordillera ambos elementos coexisten e interaccionan complejamente en el rango altitudinal comprendido entre los 1600 y los 2300–2500 m s.n.m., ocupado en su mayor parte por el piso bioclimático subalpino. Sin embargo, las interacciones que tienen lugar entre los bosques de montaña y el manto de nieve en esta región no habían sido estudiadas en profundidad hasta el momento. Y menos aún se sabía acerca de la respuesta de las interacciones bosque–nieve al proceso de calentamiento que está aconteciendo en esta cordillera y que seespera se vea acelerado en las próximas décadas. De manera que, el principal objetivo de la presente Tesis Doctoral es avanzar en el conocimiento existente sobre las interacciones que se producen entre los bosques de montaña y el manto de nieve en los Pirineos, desde una perspectiva eco–hidrológica. La misma, se presenta como un compendio de cuatro publicaciones científicas, en las que diferentes objetivos específicos son evaluados.La mayor parte de este estudio interdisciplinar tuvo lugar en un valle de montaña (Baños de Panticosa) localizado en el Pirineo central. El diseño experimental incluyó cuatro bosques de Pinus uncinata de diversas características ambientales, entre las cuales cabe mencionar su diferente elevación (desde 1674 a 2104 m s.n.m.), exposición, estructura forestal y microclimatología debido a la compleja topografía de este enclave montañoso. En estos bosques se monitorizó intensivamente, entre 2015 y 2020, la evolución del manto de nieve, las condiciones climáticas y del suelo, la fenología de los pinos, su xylogénesis, la variación intra–anual del radio de su tronco y la concentración de carbohidratos no estructurales presentes en su albura y acículas jóvenes. En este marco se contextualizó la primera publicación científica que compone esta Tesis, la cual informó con detalle sobre los efectos que la cubierta forestal produce en la dinámica del manto de nieve en esta región, destacando las similitudes y diferencias que existen entre áreas cercanas y entre distintas temporadas de invierno. La segunda publicación científica, identificó por primera vez una señal nival en el crecimiento radial inter–anual de P. uncinata. Esta investigación se contextualizó en un contexto espacio–temporal más amplio, analizando dendrocronológicamente 36 bosques de P. uncinata localizados en las principales cordilleras montañosas del NE Peninsular y las condiciones nivales acontecidas en los mismos en las últimas décadas. La tercera publicación científica, describió cómo la dinámica estacional del manto de nieve es capaz de modificar ciertas condiciones microclimáticas de los bosques estudiados en el valle de Baños de Panticosa, y demostró cómo esta influencia nival determina en buena parte el crecimiento radial intra–anual de P. uncinata. La cuarta publicación científica, exploró cómo los futuros cambios del clima pirenaico podrían afectar a las actuales interacciones bosque–nieve que tienen lugar en el valle de Baños de Panticosa. Para ello, se simularon los cambios que experimenta la dinámica nival en los bosques estudiados bajo varios grados de forzamiento climático.Los resultados obtenidos en esta Tesis demuestran, por tanto, que el manto de nieve y los bosques de P. uncinata interactúan en ambos sentidos en las áreas de montaña analizadas, si bien, tales interacciones están sujetas a importantes fuentes de variabilidad espacial y temporal. Por una parte, la cubierta forestal, principalmente debido a la intercepción que producen las copas de los pinos y a la alteración que produce en el balance de energía, determina la distribución del manto de nieve, su magnitud y su temporalidad. Por otra parte, el manto de nieve, principalmente mediante las modificaciones que produce en el régimen de temperaturas del suelo, influye en el crecimiento radial intra e inter–anual de P. uncinata, independientemente del ampliamente conocido efecto que tiene la temperatura del aire durante la temporada de crecimiento en la formación de sus anillos. Además, esta Tesis sugiere que la cubierta forestal puede tener un importante rol en la sensibilidad del manto de nieve ante los futuros cambios que se esperan en el clima de los Pirineos.Las cuestiones abordadas en esta Tesis, titulada "Estudio de las interacciones entre el manto de nieve y la cubierta forestal en el Pirineo Aragonés y sus implicaciones eco–hidrológicas", son de gran interés científico, pero también proporcionan una valiosa información de gran aplicabilidad en la presente y futura gestión de los recursos hídricos y forestales del Pirineo.<br /

    Advancing proxy-based haptic feedback in virtual reality

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    This thesis advances haptic feedback for Virtual Reality (VR). Our work is guided by Sutherland's 1965 vision of the ultimate display, which calls for VR systems to control the existence of matter. To push towards this vision, we build upon proxy-based haptic feedback, a technique characterized by the use of passive tangible props. The goal of this thesis is to tackle the central drawback of this approach, namely, its inflexibility, which yet hinders it to fulfill the vision of the ultimate display. Guided by four research questions, we first showcase the applicability of proxy-based VR haptics by employing the technique for data exploration. We then extend the VR system's control over users' haptic impressions in three steps. First, we contribute the class of Dynamic Passive Haptic Feedback (DPHF) alongside two novel concepts for conveying kinesthetic properties, like virtual weight and shape, through weight-shifting and drag-changing proxies. Conceptually orthogonal to this, we study how visual-haptic illusions can be leveraged to unnoticeably redirect the user's hand when reaching towards props. Here, we contribute a novel perception-inspired algorithm for Body Warping-based Hand Redirection (HR), an open-source framework for HR, and psychophysical insights. The thesis concludes by proving that the combination of DPHF and HR can outperform the individual techniques in terms of the achievable flexibility of the proxy-based haptic feedback.Diese Arbeit widmet sich haptischem Feedback für Virtual Reality (VR) und ist inspiriert von Sutherlands Vision des ultimativen Displays, welche VR-Systemen die Fähigkeit zuschreibt, Materie kontrollieren zu können. Um dieser Vision näher zu kommen, baut die Arbeit auf dem Konzept proxy-basierter Haptik auf, bei der haptische Eindrücke durch anfassbare Requisiten vermittelt werden. Ziel ist es, diesem Ansatz die für die Realisierung eines ultimativen Displays nötige Flexibilität zu verleihen. Dazu bearbeiten wir vier Forschungsfragen und zeigen zunächst die Anwendbarkeit proxy-basierter Haptik durch den Einsatz der Technik zur Datenexploration. Anschließend untersuchen wir in drei Schritten, wie VR-Systeme mehr Kontrolle über haptische Eindrücke von Nutzern erhalten können. Hierzu stellen wir Dynamic Passive Haptic Feedback (DPHF) vor, sowie zwei Verfahren, die kinästhetische Eindrücke wie virtuelles Gewicht und Form durch Gewichtsverlagerung und Veränderung des Luftwiderstandes von Requisiten vermitteln. Zusätzlich untersuchen wir, wie visuell-haptische Illusionen die Hand des Nutzers beim Greifen nach Requisiten unbemerkt umlenken können. Dabei stellen wir einen neuen Algorithmus zur Body Warping-based Hand Redirection (HR), ein Open-Source-Framework, sowie psychophysische Erkenntnisse vor. Abschließend zeigen wir, dass die Kombination von DPHF und HR proxy-basierte Haptik noch flexibler machen kann, als es die einzelnen Techniken alleine können

    Advances in Computational Intelligence Applications in the Mining Industry

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    This book captures advancements in the applications of computational intelligence (artificial intelligence, machine learning, etc.) to problems in the mineral and mining industries. The papers present the state of the art in four broad categories: mine operations, mine planning, mine safety, and advances in the sciences, primarily in image processing applications. Authors in the book include both researchers and industry practitioners

    Computer Aided Verification

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    This open access two-volume set LNCS 13371 and 13372 constitutes the refereed proceedings of the 34rd International Conference on Computer Aided Verification, CAV 2022, which was held in Haifa, Israel, in August 2022. The 40 full papers presented together with 9 tool papers and 2 case studies were carefully reviewed and selected from 209 submissions. The papers were organized in the following topical sections: Part I: Invited papers; formal methods for probabilistic programs; formal methods for neural networks; software Verification and model checking; hyperproperties and security; formal methods for hardware, cyber-physical, and hybrid systems. Part II: Probabilistic techniques; automata and logic; deductive verification and decision procedures; machine learning; synthesis and concurrency. This is an open access book

    Verification and refutation of C programs based on k -induction and invariant inference

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    From Springer Nature via Jisc Publications RouterHistory: registration 2020-04-23, online 2020-05-18, pub-electronic 2020-05-18, pub-print 2021-04Publication status: PublishedFunder: University of ManchesterAbstract: DepthK is a source-to-source transformation tool that employs bounded model checking (BMC) to verify and falsify safety properties in single- and multi-threaded C programs, without manual annotation of loop invariants. Here, we describe and evaluate a proof-by-induction algorithm that combines k-induction with invariant inference to prove and refute safety properties. We apply two invariant generators to produce program invariants and feed these into a k-induction-based verification algorithm implemented in DepthK, which uses the efficient SMT-based context-bounded model checker (ESBMC) as sequential verification back-end. A set of C benchmarks from the International Competition on Software Verification (SV-COMP) and embedded-system applications extracted from the available literature are used to evaluate the effectiveness of the proposed approach. Experimental results show that k-induction with invariants can handle a wide variety of safety properties, in typical programs with loops and embedded software applications from the telecommunications, control systems, and medical domains. The results of our comparative evaluation extend the knowledge about approaches that rely on both BMC and k-induction for software verification, in the following ways. (1) The proposed method outperforms the existing implementations that use k-induction with an interval-invariant generator (e.g., 2LS and ESBMC), in the category ConcurrencySafety, and overcame, in others categories, such as SoftwareSystems, other software verifiers that use plain BMC (e.g., CBMC). Also, (2) it is more precise than other verifiers based on the property-directed reachability (PDR) algorithm (i.e., SeaHorn, Vvt and CPAchecker-CTIGAR). This way, our methodology demonstrated improvement over existing BMC and k-induction-based approaches
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