1,655 research outputs found

    Geospatial Narratives and their Spatio-Temporal Dynamics: Commonsense Reasoning for High-level Analyses in Geographic Information Systems

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    The modelling, analysis, and visualisation of dynamic geospatial phenomena has been identified as a key developmental challenge for next-generation Geographic Information Systems (GIS). In this context, the envisaged paradigmatic extensions to contemporary foundational GIS technology raises fundamental questions concerning the ontological, formal representational, and (analytical) computational methods that would underlie their spatial information theoretic underpinnings. We present the conceptual overview and architecture for the development of high-level semantic and qualitative analytical capabilities for dynamic geospatial domains. Building on formal methods in the areas of commonsense reasoning, qualitative reasoning, spatial and temporal representation and reasoning, reasoning about actions and change, and computational models of narrative, we identify concrete theoretical and practical challenges that accrue in the context of formal reasoning about `space, events, actions, and change'. With this as a basis, and within the backdrop of an illustrated scenario involving the spatio-temporal dynamics of urban narratives, we address specific problems and solutions techniques chiefly involving `qualitative abstraction', `data integration and spatial consistency', and `practical geospatial abduction'. From a broad topical viewpoint, we propose that next-generation dynamic GIS technology demands a transdisciplinary scientific perspective that brings together Geography, Artificial Intelligence, and Cognitive Science. Keywords: artificial intelligence; cognitive systems; human-computer interaction; geographic information systems; spatio-temporal dynamics; computational models of narrative; geospatial analysis; geospatial modelling; ontology; qualitative spatial modelling and reasoning; spatial assistance systemsComment: ISPRS International Journal of Geo-Information (ISSN 2220-9964); Special Issue on: Geospatial Monitoring and Modelling of Environmental Change}. IJGI. Editor: Duccio Rocchini. (pre-print of article in press

    Automatic detection of disorientation among people with dementia

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    Ageing is characterized by decline in cognition including visuospatial function, necessary for independently executing instrumental activities of daily living. The onset of Alzheimer’s disease dementia exacerbates this decline, leading to major challenges for patients and increased burden for caregivers. An important function affected by this decline is spatial orientation. This work provides insight into substrates of real-world wayfinding challenges among older adults, with emphasis on viable features aiding the detection of spatial disorientation and design of possible interventions

    Personal Wayfinding Assistance

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    We are traveling many different routes every day. In familiar environments it is easy for us to find our ways. We know our way from bedroom to kitchen, from home to work, from parking place to office, and back home at the end of the working day. We have learned these routes in the past and are now able to find our destination without having to think about it. As soon as we want to find a place beyond the demarcations of our mental map, we need help. In some cases we ask our friends to explain us the way, in other cases we use a map to find out about the place. Mobile phones are increasingly equipped with wayfinding assistance. These devices are usually at hand because they are handy and small, which enables us to get wayfinding assistance everywhere where we need it. While the small size of mobile phones makes them handy, it is a disadvantage for displaying maps. Geographic information requires space to be visualized in order to be understandable. Typically, not all information displayed in maps is necessary. An example are walking ways in parks for car drivers, they are they are usually no relevant route options. By not displaying irrelevant information, it is possible to compress the map without losing important information. To reduce information purposefully, we need information about the user, the task at hand, and the environment it is embedded in. In this cumulative dissertation, I describe an approach that utilizes the prior knowledge of the user to adapt maps to the to the limited display options of mobile devices with small displays. I focus on central questions that occur during wayfinding and relate them to the knowledge of the user. This enables the generation of personal and context-specific wayfinding assistance in the form of maps which are optimized for small displays. To achieve personalized assistance, I present algorithmic methods to derive spatial user profiles from trajectory data. The individual profiles contain information about the places users regularly visit, as well as the traveled routes between them. By means of these profiles it is possible to generate personalized maps for partially familiar environments. Only the unfamiliar parts of the environment are presented in detail, the familiar parts are highly simplified. This bears great potential to minimize the maps, while at the same time preserving the understandability by including personally meaningful places as references. To ensure the understandability of personalized maps, we have to make sure that the names of the places are adapted to users. In this thesis, we study the naming of places and analyze the potential to automatically select and generate place names. However, personalized maps only work for environments the users are partially familiar with. If users need assistance for unfamiliar environments, they require complete information. In this thesis, I further present approaches to support uses in typical situations which can occur during wayfinding. I present solutions to communicate context information and survey knowledge along the route, as well as methods to support self-localization in case orientation is lost

    Effect of Dual Tasking On Walking Over Even and Uneven Surfaces in Functionally Independent Community Older Adults

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    While several studies have reported a decrement in performance by older adults while walking and concurrently performing a dual task on even surfaces, to date the effects of dual tasking while walking on uneven surfaces commonly found in the community has received less attention. Thus, we sought to test the hypothesis that an incremental decrement in gait parameters will be observed, when walking on an uneven versus an even surface and furthermore, that this decrement would be dependent upon the concurrent performance of a secondary cognitive and/or motor task in functionally independent-living-community older adults. Dynamic Gait Index assessed the subject’s ability to modify gait in response to changing task demands and Mini Mental State Examination was used to screen cognitive functionof the participants. Twenty-eight participants walked at a comfortable speed over the GAITRiteTM walkway placed over an even and uneven surface. Twenty-four strips of wood measuring 0.10 square meters and 0.05 meter high attached randomly under the smooth surface of an artificial grass mat measuring 6 meter long and 1.2 meter in width simulated a natural uneven surface. Each participant randomly performed a total of three (3) trials each under the following four task conditions as they walked over an even or uneven surface: 1) no secondary task (single task), 2) concurrent cognitive task, 3) concurrent motor task, 4) concurrent cognitive-motor task. The presentation of the task conditions were counterbalanced across subjects. Gait speed, cadence, stride time, and double support time were analyzed using a 2 x 4 repeated measures ANOVA. Also, to quantify subjects\u27 ability for executing two tasks concurrently, we calculated the dual task costs. In addition, the cognitive, motor and cognitive/motor tasks performances on even and uneven surfaces were assessed using Mann-Whitney U. The results of these analyses revealed significant main effects for concurrent dual-tasking as well as surface for speed [F(1.86,50)= 21.93; p ≤ 0.05; F(1,27)= 24.3, p ≤ 0.05] , cadence [F(1.85,50)=33.824; p ≤ 0.05. F(1,27)= 22.2, p ≤ 0.05], stride time [F(1.94,52.34)= 33.41, p ≤ 0.05; F(1,27)= 23.49, p ≤ 0.05], and double support time [F(1.99,53.62)= 7.4; p ≤ 0.05; F(1,27)= 7.4, p = .011]. It was observed that the elderly slow down, take a lesser number of steps per minute, increase their stride time and spend more time in double support when walking on uneven surfaces and when performing a concurrent dual-task. However, interaction effects failed to achieve significance. This study provides some preliminary evidence that independent, community living older adults use a default strategy that rely on making adjustments in gait that result in greater motor control. In other words the older adults err on the side of safety and focus their anticipatory resources towards controlling balance. It is important for clinicians to be aware of these strategies and incorporate them in the management of the elderly patient

    Semantic and pragmatic motivations for constructional preferences: a corpus-based study of provide, supply, and present

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    A select group of transfer verbs can enter into four different constructions: the ditransitive construction (He provided John the money), the prepositional-dative construction (He provided the money to John), a construction with a prepositional theme (He provided John with the money), and a construction with a recipient realized by a for-phrase (He provided the money for John). In this article, we take a close look at three such verbs: provide, supply, and present. Corpus analysis shows that these three verbs display different structural preferences with respect to the for-, to-, and with-patterns. To explain these preferences, the study investigates pragmatic principles (following Mukherjee 2001 on provide) and the role played by semantic factors. An examination of the semantics of the verbs and the lexically motivated constructional semantics of the to, for, and with-patterns shows (i) that the three constructions are not interchangeable, and (ii) that the preferential differences between the three verbs find an explanation in the compatibility between lexical and constructional semantics. The description is mainly based on data from the British National Corpus

    Cognitive Principles of Schematisation for Wayfinding Assistance

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    People often need assistance to successfully perform wayfinding tasks in unfamiliar environments. Nowadays, a huge variety of wayfinding assistance systems exists. All these systems intend to present the needed information for a certain wayfinding situation in an adequate presentation. Some wayfinding assistance systems utilize findings for the field of cognitive sciences to develop and design cognitive ergonomic approaches. These approaches aim to be systems with which the users can effortless interact with and which present needed information in a way the user can acquire the information naturally. Therefore it is necessary to determinate the information needs of the user in a certain wayfinding task and to investigate how this information is processed and conceptualised by the wayfinder to be able to present it adequately. Cognitive motivated schematic maps are an example which employ this knowledge and emphasise relevant information and present it in an easily readable way. In my thesis I present a transfer approach to reuse the knowledge of well-grounded knowledge of schematisation techniques from one externalisation such as maps to another externalization such as virtual environments. A analysis of the informational need of the specific wayfinding task route following is done one the hand of a functional decomposition as well as a deep analysis of representation-theoretic consideration of the external representations maps and virtual environments. Concluding from these results, guidelines for transferring schematisation principles between different representation types are proposed. Specifically, this thesis chose the exemplary transfer of the schematisation technique wayfinding choremes from a map presentation into a virtual environment to present the theoretic requirements for a successful transfer. Wayfinding choremes are abstract mental concepts of turning action which are accessible as graphical externalisation integrated into route maps. These wayfinding choremes maps emphasis the turning action along the route by displaying the angular information as prototypes of 45° or 90°. This schematisation technique enhances wayfinding performance by supporting the matching processes between the map representation and the internal mental representation of the user. I embed the concept of wayfinding choremes into a virtual environment and present a study to test if the transferred schematisation technique also enhance the wayfinding performance. The empirical investigations present a successful transfer of the concept of the wayfinding choremes. Depending on the complexity of the route the embedded schematization enhance the wayfinding performance of participants who try to follow a route from memory. Participants who trained and recall the route in a schematised virtual environment make fewer errors than the participants of the unmodified virtual world. This thesis sets an example of the close research circle of cognitive behavioural studies to representation-theoretical considerations to applications of wayfinding assistance and their evaluations back to new conclusions in cognitive science. It contributes an interdisciplinary comprehensive inspection of the interplay of environmental factors and mental processes on the example of angular information and mental distortion of this information

    Locomotion Traces Data Mining for Supporting Frail People with Cognitive Impairment

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    The rapid increase in the senior population is posing serious challenges to national healthcare systems. Hence, innovative tools are needed to early detect health issues, including cognitive decline. Several clinical studies show that it is possible to identify cognitive impairment based on the locomotion patterns of older people. Thus, this thesis at first focused on providing a systematic literature review of locomotion data mining systems for supporting Neuro-Degenerative Diseases (NDD) diagnosis, identifying locomotion anomaly indicators and movement patterns for discovering low-level locomotion indicators, sensor data acquisition, and processing methods, as well as NDD detection algorithms considering their pros and cons. Then, we investigated the use of sensor data and Deep Learning (DL) to recognize abnormal movement patterns in instrumented smart-homes. In order to get rid of the noise introduced by indoor constraints and activity execution, we introduced novel visual feature extraction methods for locomotion data. Our solutions rely on locomotion traces segmentation, image-based extraction of salient features from locomotion segments, and vision-based DL. Furthermore, we proposed a data augmentation strategy to increase the volume of collected data and generalize the solution to different smart-homes with different layouts. We carried out extensive experiments with a large real-world dataset acquired in a smart-home test-bed from older people, including people with cognitive diseases. Experimental comparisons show that our system outperforms state-of-the-art methods
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