181,628 research outputs found

    Towards an Indexical Model of Situated Language Comprehension for Cognitive Agents in Physical Worlds

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    We propose a computational model of situated language comprehension based on the Indexical Hypothesis that generates meaning representations by translating amodal linguistic symbols to modal representations of beliefs, knowledge, and experience external to the linguistic system. This Indexical Model incorporates multiple information sources, including perceptions, domain knowledge, and short-term and long-term experiences during comprehension. We show that exploiting diverse information sources can alleviate ambiguities that arise from contextual use of underspecific referring expressions and unexpressed argument alternations of verbs. The model is being used to support linguistic interactions in Rosie, an agent implemented in Soar that learns from instruction.Comment: Advances in Cognitive Systems 3 (2014

    The neurocognitive gains of diagnostic reasoning training using simulated interactive veterinary cases

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    The present longitudinal study ascertained training-associated transformations in the neural underpinnings of diagnostic reasoning, using a simulation game named “Equine Virtual Farm” (EVF). Twenty participants underwent structural, EVF/task-based and resting-state MRI and diffusion tensor imaging (DTI) before and after completing their training on diagnosing simulated veterinary cases. Comparing playing veterinarian versus seeing a colorful image across training sessions revealed the transition of brain activity from scientific creativity regions pre-training (left middle frontal and temporal gyrus) to insight problem-solving regions post-training (right cerebellum, middle cingulate and medial superior gyrus and left postcentral gyrus). Further, applying linear mixed-effects modelling on graph centrality metrics revealed the central roles of the creative semantic (inferior frontal, middle frontal and angular gyrus and parahippocampus) and reward systems (orbital gyrus, nucleus accumbens and putamen) in driving pre-training diagnostic reasoning; whereas, regions implicated in inductive reasoning (superior temporal and medial postcentral gyrus and parahippocampus) were the main post-training hubs. Lastly, resting-state and DTI analysis revealed post-training effects within the occipitotemporal semantic processing region. Altogether, these results suggest that simulation-based training transforms diagnostic reasoning in novices from regions implicated in creative semantic processing to regions implicated in improvised rule-based problem-solving

    A pathway to independence : wayfinding systems which adapt to a visually impaired person's context

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    Despite an increased amount of technologies and systems designed to address the navigational requirements of the visually impaired community of approximately 7.4 million in Europe, current research has failed to sufficiently address the human issues associated to their design and use. As more types of sensing technologies are developed to facilitate visually impaired travellers for different navigational purposes (local vs. distant and indoor vs. outdoor), an effective process of synchronisation is required. This synchronisation is represented through context-aware computing, which allows contextual information to not just be sensed (like most current wayfinding systems), but also adapted, discovered and augmented. In this paper, three user studies concerning the suitability of different types of navigational information for visually impaired and sighted people are described. For such systems to be effective, human cognitive maps, models and intentions need to be the focus of further research, in order to provide information that is tailored to a user's task, situation or environment. Methodologies aimed at establishing these issues need to be demonstrated through a multidisciplinary framework

    Role of right posterior parietal cortex in maintaining attention to spatial locations over time

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    Recent models of human posterior parietal cortex (PPC) have variously emphasized its role in spatial perception, visuomotor control or directing attention. However, neuroimaging and lesion studies also suggest that the right PPC might play a special role in maintaining an alert state. Previously, assessments of right-hemisphere patients with hemispatial neglect have revealed significant overall deficits on vigilance tasks, but to date there has been no demonstration of a deterioration of performance over time--a vigilance decrement--considered by some to be a key index of a deficit in maintaining attention. Moreover, sustained attention deficits in neglect have not specifically been related to PPC lesions, and it remains unclear whether they interact with spatial impairments in this syndrome. Here we examined the ability of right-hemisphere patients with neglect to maintain attention, comparing them to stroke controls and healthy individuals. We found evidence of an overall deficit in sustaining attention associated with PPC lesions, even for a simple detection task with stimuli presented centrally. In a second experiment, we demonstrated a vigilance decrement in neglect patients specifically only when they were required to maintain attention to spatial locations, but not verbal material. Lesioned voxels in the right PPC spanning a region between the intraparietal sulcus and inferior parietal lobe were significantly associated with this deficit. Finally, we compared performance on a task that required attention to be maintained either to visual patterns or spatial locations, matched for task difficulty. Again, we found a vigilance decrement but only when attention had to be maintained on spatial information. We conclude that sustaining attention to spatial locations is a critical function of the human right PPC which needs to be incorporated into models of normal parietal function as well as those of the clinical syndrome of hemispatial neglect

    Interaction between high-level and low-level image analysis for semantic video object extraction

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    Authors of articles published in EURASIP Journal on Advances in Signal Processing are the copyright holders of their articles and have granted to any third party, in advance and in perpetuity, the right to use, reproduce or disseminate the article, according to the SpringerOpen copyright and license agreement (http://www.springeropen.com/authors/license)

    From intersubjectivity to interculturalism in digital learning environments

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    The paper presents the work of the research program “Studies on\ud Intermediality as Intercultural Mediation” a joint international venture that seeks\ud to provide blended-learning -both online and in-classroom- methodologies for the\ud development of interculturalism and associated emotional empathic responses\ud through the study of art and literary fiction.1\ud Technological development is consistent with human desire to draw on\ud previous information and experiences in order to apply acquired knowledge to\ud present life conditions and, furthermore, make improvements for the future.\ud Therefore, it is logical that human agentive consciousness has been directed\ud towards encouraging action at a distance by all possible means. The evolution in\ud media technologies bears witness to this fact.\ud This paper explores the paradoxes behind the growing emphasis on spatial\ud metaphors during the 20th-century and a dynamic concept of space as the site of\ud relational constructions where forms and structural patterns become formations\ud constructed in interaction, and where the limit or border becomes a constitutive\ud feature, immanently connected with the possibility of its transgression. The paper\ud contends that the development of mass media communication, and particularly the\ud digital turn, has dramatically impacted on topographical spaces, both sociocultural and individual, and that the emphasis on „inter‟ perspectives, hybridism,\ud ambiguities, differences and meta-cognitive articulations of awareness of limits\ud and their symbolic representations, and the desire either to transgress limits or to\ud articulate „in-between‟, intercultural „third spaces‟, etc. are symptomatic of\ud structural problems at the spatial-temporal interface of culture and its\ud representations. Finally, the paper brings into attention research on the\ud neuroscientific basis of intersubjectivity in order to point out the material basis of\ud human knowledge and cognition and its relationship to the archiving of historical\ud memory and information transfer through education. It also offers and brief\ud introduction to the dynamics of SIIM

    From single steps to mass migration: the problem of scale in the movement ecology of the Serengeti wildebeest

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    A central question in ecology is how to link processes that occur over different scales. The daily interactions of individual organisms ultimately determine community dynamics, population fluctuations and the functioning of entire ecosystems. Observations of these multiscale ecological processes are constrained by various technological, biological or logistical issues, and there are often vast discrepancies between the scale at which observation is possible and the scale of the question of interest. Animal movement is characterized by processes that act over multiple spatial and temporal scales. Second-by-second decisions accumulate to produce annual movement patterns. Individuals influence, and are influenced by, collective movement decisions, which then govern the spatial distribution of populations and the connectivity of meta-populations. While the field of movement ecology is experiencing unprecedented growth in the availability of movement data, there remain challenges in integrating observations with questions of ecological interest. In this article, we present the major challenges of addressing these issues within the context of the Serengeti wildebeest migration, a keystone ecological phenomena that crosses multiple scales of space, time and biological complexity. This article is part of the theme issue ’Collective movement ecology’

    Disentangling scale approaches in governance research: comparing monocentric, multilevel, and adaptive governance

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    The question of how to govern the multiscale problems in today’s network society is an important topic in the fields of public administration, political sciences, and environmental sciences. How scales are defined, studied, and dealt with varies substantially within and across these fields. This paper aims to reduce the existing conceptual confusion regarding scales by disentangling three representative approaches that address both governance and scaling: monocentric governance, multilevel governance, and adaptive governance. It does so by analyzing the differences in (1) underlying views on governing, (2) assumptions about scales, (3) dominant problem definitions regarding scales, and (4) preferred responses for dealing with multiple scales. Finally, this paper identifies research opportunities within and across these approaches

    Temporally Graded Activation of Neocortical Regions in Response to Memories of Different Ages

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    The temporally graded memory impairment seen in many neurobehavioral disorders implies different neuroanatomical pathways and/or cognitive mechanisms involved in storage and retrieval of memories of different ages. A dynamic interaction between medial-temporal and neocortical brain regions has been proposed to account for memory\u27s greater permanence with time. Despite considerable debate concerning its time-dependent role in memory retrieval, medial-temporal lobe activity has been well studied. However, the relative participation of neocortical regions in recent and remote memory retrieval has received much less attention. Using functional magnetic resonance imaging, we demonstrate robust, temporally graded signal differences in posterior cingulate, right middle frontal, right fusiform, and left middle temporal regions in healthy older adults during famous name identification from two disparate time epochs. Importantly, no neocortical regions demonstrated greater response to older than to recent stimuli. Our results suggest a possible role of these neocortical regions in temporally dating items in memory and in establishing and maintaining memory traces throughout the lifespan. Theoretical implications of these findings for the two dominant models of remote memory functioning (Consolidation Theory and Multiple Trace Theory) are discussed
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