7,321 research outputs found

    From Raw Data to Meaningful Information: A Representational Approach to Cadastral Databases in Relation to Urban Planning

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    Digesting the data hose that cities are constantly producing is complex; data is usually structured with different criteria, which makes comparative analysis of multiple cities challenging. However, the publicly available data from the Spanish cadaster contains urban information in a documented format with common semantics for the whole territory, which makes these analyses possible. This paper uses the information about the 3D geometry of buildings, their use and their year of construction, stored in cadastral databases, to study the relation between the built environment (what the city is) and the urban plan (what the city wants to become), translating the concepts of the cadastral data into the semantics of the urban plan. Different representation techniques to better understand the city from the pedestrians’ point of view and to communicate this information more effectively are also discussed.Postprint (published version

    Decision Making Under Threat: An Ecological Framework

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    Humans, like other animals, have evolved a set of neural circuits whose primary function is survival. In the case of predation, these circuits include "reactive fear" circuits involved in fast escape decisions, and "cognitive fear" circuits that are involved in more complex processing associated with slow strategic escape. In the context of flight initiation distance (FID), using neuroimaging combined with computational modeling, we support this differentiation of fear circuits by showing that fast escape decisions are elicited by the periaqueductal gray and midcingulate cortex, regions involved in reactive flight. Conversely, slower escape decisions rely on the hippocampus, posterior cingulate cortex, and prefrontal cortex, a circuit implicated in behavioral flexibility. We further tested whether individual differences in trait anxiety would impact escape behavior and neural responses to slow and fast attacking predators. Behaviorally, we found that trait anxiety was not related to escape decisions for fast threats, but individuals with higher trait anxiety escaped earlier during slow threats. Functional MRI showed that when subjects faced slow threats, trait anxiety positively correlated with activity in the vHPC, mPFC, amygdala and insula. Further, the strength of the functional coupling between the vHPC and mPFC was correlated with the degree of trait anxiety. A similar pattern of separation in survival circuits is also found in a follow up study utilizing the concept of margin of safety (MOS) with multivariate pattern analysis of fMRI data. In addition, we also discussed how decision making under threat was influenced by social factors such as reputation. Overall, these results provide new insights into decision making under threat and a separation of fear into reactive and cognitive circuits.</p

    A Simple(r) Tool For Examining Fixations

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    This short paper describes an update of A Simple Tool For Examining Fixations (ASTEF) developed for facilitating the examination of eye-tracking data and for computing a spatial statistics algorithm that has been validated as a measure of mental workload (namely, the Nearest Neighbor Index: NNI). The code is based on MatlabÂź 2013a and is currently distributed on the web as an open-source project. This implementation of ASTEF got rid of many functionalities included in the previous version that are not needed anymore considering the large availability of commercial and open-source software solutions for eye-tracking. That makes it very easy to compute the NNI on eye-tracking data without the hassle of learning complicated tools. The software also features an export function for creating the time series of the NNI values computed on each minute of the recording. This feature is crucial given that the spatial distribution of fixations must be used to test hypotheses about the time course of mental load

    Usability guidelines informing knowledge visualisation in demonstrating learners' knowledge acquisition

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    There is growing evidence that knowledge co-creation and interactivity during learning interventions aid knowledge acquisition and knowledge transfer. However, learners have mostly been passive consumers and not co-creators of the knowledge visualisation aids created by teachers and instructional designers. As such, knowledge visualisation has been underutilised for allowing learners to construct, demonstrate and share what they have learned. The dearth of appropriate guidelines for the use of knowledge visualisation for teaching and learning is an obstacle to using knowledge visualisation in teaching and learning. This provides a rationale for this study, which aims to investigate usability-based knowledge visualisation guidelines for teaching and learning. The application context is that of Science teaching for high school learners in the Gauteng province of South Africa. Following a design-based research methodology, an artefact of usability-based knowledge visualisation guidelines was created. The artefact was evaluated by testing learners’ conformity to the visualisation guidelines. Qualitative and quantitative data was captured using questionnaires, interviews and observations. The findings indicate that the guidelines considered in this study had various degrees of impact on the visualisations produced by learners. While some made noticeable impact, for others it could be considered negligible. Within the context of high school learning, these results justify the prioritisation of usability-based knowledge visualisation guidelines. Integrating Human Computer Interaction usability principles and knowledge visualisation guidelines to create usability-based knowledge visualisation guidelines provide a novel theoretical contribution upon which scientific knowledge visualisation can be expanded.School of ComputingM. Sc. (Computing

    Visual integration of geodata in thematic cartography

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    Contemporary cartographic production requires working with databases, of various topographic and thematic structures, which must be standardized and with the possibility of converting values from one data type to another. In order to better map out the reality, in the modeling process, the geodata are systematized within the databases, graphically integrated in regard to thematic significance (primary and secondary). Cartographic methods of geo-visualization offer numerous solutions for interactive visual representation of thematic content. Adjusting the graphic representation and ways of interaction while using the cartographic models allow the visualization of the "hidden" content provided by geodata. By integrating standardized data, in the framework of a database (classification, standardization ...), besides the basic cartographic representation, the interconnected and conditioned additional and supplementary, synchronized graphical representations of the cartographic issues can be realized. Synchronized representations can originate from the same database as the basic map or they can be made by combining data from multiple different databases (with the ability to manipulate within the same formats, classifications, standardizations ...). In doing so, the interactive capabilities in manipulating the maps must be well thought out and evaluated. The approach, ways and limits of database manipulation, as well as the offered cartographic visualization solutions, should provide users with highlighting of the most important aspects of the representation. The coordination of different, but synchronized representations is enabled by visual integration of geodata, in order to create a geo-visual environment in the context of understanding large amounts of data (content, space and time). A complex structure of geodata can be cartographically integrated and presented if it is adapted and based on the principles of cartographic generalization and cartographic design. The content generalization on a model can be the following: taxonomical, spatial, attributive and graphical. The content generalization and symbolization of the thematic maps are key procedures for geo-visualization. The degree of generalization (geometric and semantic) influences the degree of data integration that are graphically represented

    Communicating thematic data quality with web map services

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    Geospatial information of many kinds, from topographic maps to scientific data, is increasingly being made available through web mapping services. These allow georeferenced map images to be served from data stores and displayed in websites and geographic information systems, where they can be integrated with other geographic information. The Open Geospatial Consortium’s Web Map Service (WMS) standard has been widely adopted in diverse communities for sharing data in this way. However, current services typically provide little or no information about the quality or accuracy of the data they serve. In this paper we will describe the design and implementation of a new “quality-enabled” profile of WMS, which we call “WMS-Q”. This describes how information about data quality can be transmitted to the user through WMS. Such information can exist at many levels, from entire datasets to individual measurements, and includes the many different ways in which data uncertainty can be expressed. We also describe proposed extensions to the Symbology Encoding specification, which include provision for visualizing uncertainty in raster data in a number of different ways, including contours, shading and bivariate colour maps. We shall also describe new open-source implementations of the new specifications, which include both clients and servers

    Comparison of the ERA5 Wave Forecasting Dataset against Buoy Record

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    Appropriate design of marine structures, such as offshore facilities and harbours, requires a detailed estimation of synthetic wave parameters. Inaccuracies and unreliability of wave data have implications in many aspects of marine engineering, such as structural strength, cost, and design. In this paper, a critical analysis of the most common data acquisition methods is made, focusing on in-situ instrumentation and numerical models. Considering the Pantelleria island as case study, records of a proprietary wave buoy and the ERA5 dataset of ECMWF (European Centre for Medium-Range Weather Forecasts) have been compared. This paper first highlights the methods and challenges of offshore experimental campaigns for wave monitoring and eventually presents a critical and quantitative comparison of the two approaches (experimental versus numerical), highlighting their respective advantages and disadvantages

    A partition of unity approach to fluid mechanics and fluid-structure interaction

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    For problems involving large deformations of thin structures, simulating fluid-structure interaction (FSI) remains challenging largely due to the need to balance computational feasibility, efficiency, and solution accuracy. Overlapping domain techniques have been introduced as a way to combine the fluid-solid mesh conformity, seen in moving-mesh methods, without the need for mesh smoothing or re-meshing, which is a core characteristic of fixed mesh approaches. In this work, we introduce a novel overlapping domain method based on a partition of unity approach. Unified function spaces are defined as a weighted sum of fields given on two overlapping meshes. The method is shown to achieve optimal convergence rates and to be stable for steady-state Stokes, Navier-Stokes, and ALE Navier-Stokes problems. Finally, we present results for FSI in the case of a 2D mock aortic valve simulation. These initial results point to the potential applicability of the method to a wide range of FSI applications, enabling boundary layer refinement and large deformations without the need for re-meshing or user-defined stabilization.Comment: 34 pages, 15 figur
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