223 research outputs found

    On discriminating temporal relations: Is it relational?

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    Pigeons were presented on each trial with a pair of keylight stimuli that varied in duration. One of two subsequent choices was reinforced, depending on which of the two stimuli was longer. For some pairs, the duration of one stimulus was predictive of relative duration, but for other pairs, absolute duration was unpredictive. Choice responses depended on relative differences between the stimuli, but were also controlled to some degree by absolute duration of the second member of the pair. Individual differences in control by absolute and relative duration were evident. Those pigeons whose behavior was most influenced by absolute duration showed poorer transfer to a different set of duration pairs

    Active versus passive acquisition of spatial knowledge while controlling a vehicle in a virtual urban space in drivers and non-drivers

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    Historically real world studies have indicated a spatial learning advantage for active explorers of environments over those whose experience is more passive; a common contrast is made between car drivers and passengers. An experiment was conducted to explore the dual hypotheses that active explorers learn more about the layout of a virtual environment than passive observers and that real world car drivers will learn more regardless of their experimental Active/Passive status. Consistent with earlier studies in VEs, there was no benefit from activity (controlling exploration/movement), arguably because input control competes with spatial information acquisition. However, the results showed that Drivers were more accurate than Non-Drivers at indicating the positions of target locations on a map, in both active and passive conditions and had better route scores than Non-Drivers in the passive condition. It is argued that driving experience may convey a spatial learning advantage over and above activity per se

    Light Quality Effects on Germination and Conversion of Southern Pine Somatic Embryos

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    Papers and abstracts from the 27th Southern Forest Tree Improvement Conference held at Oklahoma State University in Stillwater, Oklahoma on June 24-27, 2003

    SOWL QL: Querying Spatio - Temporal Ontologies in OWL

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    We introduce SOWL QL, a query language for spatio-temporal information in ontologies. Buildingupon SOWL (Spatio-Temporal OWL), an ontology for handling spatio-temporal information in OWL, SOWL QL supports querying over qualitative spatio-temporal information (expressed using natural language expressions such as “before”, “after”, “north of”, “south of”) rather than merely quantitative information (exact dates, times, locations). SOWL QL extends SPARQL with a powerful set of temporal and spatial operators, including temporal Allen topological, spatial directional and topological operations or combinations of the above. SOWL QL maintains simplicity of expression and also, upward and downward compatibility with SPARQL. Query translation in SOWL QL yields SPARQL queries implying that, querying spatio-temporal ontologies using SPARQL is still feasible but suffers from several drawbacks the most important of them being that, queries in SPARQL become particularly complicated and users must be familiar with the underlying spatio-temporal representation (the “N-ary relations” or the “4D-fluents” approach in this work). Finally, querying in SOWL QL is supported by the SOWL reasoner which is not part of the standard SPARQL translation. The run-time performance of SOWL QL has been assessed experimentally in a real data setting. A critical analysis of its performance is also presented

    The process of spatial knowledge acquisition in a square and a circular virtual environment

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    This study investigated the effect of the environmental structure (circular vs. square environment) on spatial knowledge acquisition in a desktop virtual situation in which self-determined movement was allowed with a total of 120 participants: 7-, 8-year-old children; 11, 12-year-old children, and adults. In all measurements of spatial knowledge acquisition an overall developmental performance increase from younger children to adults was found. In contrast to that, the exploration and learning behavior did not differ between adults and children. Furthermore, the environmental structure influencedthenumber of trials needed to learn the two routes used and the distance walked to the determined landmarks. All these tasks were easier in a circular than in a square environment. This influenceofthe environmental structure was absent in the direction estimations task. The advantage of spatial knowledge acquisition in a circular environment in three of four tasks is discussed

    Exploring an absent presence: Wayfinding as an embodied sociocultural experience

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    Wayfinding has often been seen as being about the quickest or shortest possible route between two points (Hölscher et al 2011; Tam 2011; Haque et al 2006). Moreover, this process has very often been seen as a cognitive one, with the experiential nature of wayfinding and with the embodied, emotional and sociocultural aspects of this experience conspicuously absent. We argue that wayfinding is rarely a purely cognitive process that involves an individual person, who is entirely instrumental in navigating a direct and precise route, but instead that this is a process almost always directed according to embodied and sociocultural needs. We propose a reassessment of present wayfinding definitions and suggest an alternative understanding that includes sociocultural elements, embodied individuals and experience through their embodied senses, as crucial elements of the concept. Seeing wayfinding from this different sociocultural ontological viewpoint, opens up new ways of understanding and planning wayfinding systems

    Assessing the Impact of Automatic vs. Controlled Rotations on Spatial Transfer with a Joystick and a Walking Interface in VR

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    Part 1: Long and Short PapersInternational audienceWe present a user study assessing spatial transfer in a 3D navigation task, with two different motor activities: a minimal (joystick) and an extensive motor activity (walking Interface), with rotations of the viewpoint either controlled by the user, or automatically managed by the system. The task consisted in learning a virtual path of a 3D model of a real city, with either one of these four conditions: Joystick / Treadmill Vs Manual Rotation / Automatic Rotation. We assessed spatial knowledge with six spatial restitution tasks. To assess the interfaces used, we analyzed also the interaction data acquired during the learning path. Our results show that the direct control of rotations has different effects, depending on the motor activity required by the input modality. The quality of spatial representation increases with the Treadmill when rotations are enabled. With the Joystick, controlling the rotations affect spatial representations. We discuss our findings in terms of cognitive, sensorimotor processes and human computer interaction issues

    Route knowledge and configural knowledge in typical and atypical development: a comparison of sparse and rich environments

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    Background: Individuals with Down syndrome (DS) and individuals with Williams syndrome (WS) have poor navigation skills, which impact their potential to become independent. Two aspects of navigation were investigated in these groups, using virtual environments (VE): route knowledge (the ability to learn the way from A to B by following a fixed sequence of turns) and configural knowledge (knowledge of the spatial relationships between places within an environment). Methods: Typically developing (TD) children aged 5 to 11 years (N = 93), individuals with DS (N = 29) and individuals with WS (N = 20) were presented with a sparse and a rich VE grid maze. Within each maze, participants were asked to learn a route from A to B and a route from A to C before being asked to find a novel shortcut from B to C. Results: Performance was broadly similar across sparse and rich mazes. The majority of participants were able to learn novel routes, with poorest performance in the DS group, but the ability to find a shortcut, our measure of configural knowledge, was limited for all three groups. That is, 59 % TD participants successfully found a shortcut, compared to 10 % participants with DS and 35 % participants with WS. Differences in the underlying mechanisms associated with route knowledge and configural knowledge and in the developmental trajectories of performance across groups were observed. Only the TD participants walked a shorter distance in the last shortcut trial compared to the first, indicative of increased configural knowledge across trials. The DS group often used an alternative strategy to get from B to C, summing the two taught routes together. Conclusions: Our findings demonstrate impaired configural knowledge in DS and in WS, with the strongest deficit in DS. This suggests that these groups rely on a rigid route knowledge based method for navigating and as a result are likely to get lost easily. Route knowledge was also impaired in both DS and WS groups and was related to different underlying processes across all three groups. These are discussed with reference to limitations in attention and/or visuo-spatial processing in the atypical groups
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