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Sample records for allocentric spatial information

  1. Allocentric coding: spatial range and combination rules.

    PubMed

    Camors, D; Jouffrais, C; Cottereau, B R; Durand, J B

    2015-04-01

    When a visual target is presented with neighboring landmarks, its location can be determined both relative to the self (egocentric coding) and relative to these landmarks (allocentric coding). In the present study, we investigated (1) how allocentric coding depends on the distance between the targets and their surrounding landmarks (i.e. the spatial range) and (2) how allocentric and egocentric coding interact with each other across targets-landmarks distances (i.e. the combination rules). Subjects performed a memory-based pointing task toward previously gazed targets briefly superimposed (200ms) on background images of cluttered city landscapes. A variable portion of the images was occluded in order to control the distance between the targets and the closest potential landmarks within those images. The pointing responses were performed after large saccades and the reappearance of the images at their initial location. However, in some trials, the images' elements were slightly shifted (±3°) in order to introduce a subliminal conflict between the allocentric and egocentric reference frames. The influence of allocentric coding in the pointing responses was found to decrease with increasing target-landmarks distances, although it remained significant even at the largest distances (⩾10°). Interestingly, both the decreasing influence of allocentric coding and the concomitant increase in pointing responses variability were well captured by a Bayesian model in which the weighted combination of allocentric and egocentric cues is governed by a coupling prior. PMID:25749676

  2. Impaired allocentric spatial memory underlying topographical disorientation.

    PubMed

    Burgess, Neil; Trinkler, Iris; King, John; Kennedy, Angus; Cipolotti, Lisa

    2006-01-01

    The cognitive processes supporting spatial navigation are considered in the context of a patient (CF) with possible very early Alzheimer's disease who presents with topographical disorientation. Her verbal memory and her recognition memory for unknown buildings, landmarks and outdoor scenes was intact, although she showed an impairment in face processing. By contrast, her navigational ability, quantitatively assessed within a small virtual reality (VR) town, was significantly impaired. Interestingly, she showed a selective impairment in a VR object-location memory test whenever her viewpoint was shifted between presentation and test, but not when tested from the same viewpoint. We suggest that a specific impairment in locating objects relative to the environment rather than relative to the perceived viewpoint (i.e. allocentric rather than egocentric spatial memory) underlies her topographical disorientation. We discuss the likely neural bases of this deficit in the light of related studies in humans and animals, focusing on the hippocampus and related areas. The specificity of our test indicates a new way of assessing topographical disorientation, with possible application to the assessment of progressive dementias such as Alzheimer's disease. PMID:16703955

  3. A comparison of egocentric and allocentric age-dependent spatial learning in the beagle dog.

    PubMed

    Christie, Lori-Ann; Studzinski, Christa M; Araujo, Joseph A; Leung, Cleo S K; Ikeda-Douglas, Candace J; Head, Elizabeth; Cotman, Carl W; Milgram, Norton W

    2005-03-01

    Spatial discriminations can be performed using either egocentric information based on body position or allocentric information based on the position of landmarks in the environment. Beagle dogs ranging from 2 to 16 years of age were tested for their ability to learn a novel egocentric spatial discrimination task that used two identical blocks paired in three possible spatial positions (i.e. left, center and right). Dogs were rewarded for responding to an object furthest to either their left or right side. Therefore, when the center location was used, it was correct on half of the trials and incorrect on the other half. Upon successful acquisition of the task, the reward contingencies were reversed, and the dogs were rewarded for responding to the opposite side. A subset of dogs was also tested on an allocentric spatial discrimination task, landmark discrimination. Egocentric spatial reversal learning and allocentric discrimination learning both showed a significant age-dependent decline, while initial egocentric learning appeared to be age-insensitive. Intra-subject correlation analyses revealed a significant relationship between egocentric reversal learning and allocentric learning. However, the correlation only accounted for a small proportion of the variance, suggesting that although there might be some common mechanism underlying acquisition of the two tasks, additional unique neural substrates were involved depending on whether allocentric or egocentric spatial information processing was required. PMID:15795044

  4. Impaired allocentric spatial processing in posttraumatic stress disorder

    PubMed Central

    Smith, Kirsten V.; Burgess, Neil; Brewin, Chris R.; King, John A.

    2015-01-01

    A neurobiological dual representation model of PTSD proposes that reduced hippocampus-dependent contextual processing contributes to intrusive imagery due to a loss of control over hippocampus-independent sensory and affective representations. We investigated whether PTSD sufferers show impaired allocentric spatial processing indicative of reduced hippocampal functioning. Trauma-exposed individuals with (N = 29) and without (N = 30) a diagnosis of PTSD completed two tests of spatial processing: a topographical recognition task comprising perceptual and memory components, and a test of memory for objects’ locations within a virtual environment in which the test is from either the same viewpoint as presentation (solvable with egocentric memory) or a different viewpoint (requiring allocentric memory). Participants in the PTSD group performed significantly worse on allocentric spatial processing than trauma-exposed controls. Groups performed comparably on egocentric memory and non-spatial memory for lists of objects. Exposure to repeated incident trauma was also associated with significantly worse spatial processing in the PTSD group. Results show a selective impairment in allocentric spatial processing, implicating weak hippocampal functioning, as predicted by a neurobiological dual representation model of PTSD. These findings have important clinical implications for cognitive therapy. PMID:25636201

  5. Impaired allocentric spatial processing in posttraumatic stress disorder.

    PubMed

    Smith, Kirsten V; Burgess, Neil; Brewin, Chris R; King, John A

    2015-03-01

    A neurobiological dual representation model of PTSD proposes that reduced hippocampus-dependent contextual processing contributes to intrusive imagery due to a loss of control over hippocampus-independent sensory and affective representations. We investigated whether PTSD sufferers show impaired allocentric spatial processing indicative of reduced hippocampal functioning. Trauma-exposed individuals with (N=29) and without (N=30) a diagnosis of PTSD completed two tests of spatial processing: a topographical recognition task comprising perceptual and memory components, and a test of memory for objects' locations within a virtual environment in which the test is from either the same viewpoint as presentation (solvable with egocentric memory) or a different viewpoint (requiring allocentric memory). Participants in the PTSD group performed significantly worse on allocentric spatial processing than trauma-exposed controls. Groups performed comparably on egocentric memory and non-spatial memory for lists of objects. Exposure to repeated incident trauma was also associated with significantly worse spatial processing in the PTSD group. Results show a selective impairment in allocentric spatial processing, implicating weak hippocampal functioning, as predicted by a neurobiological dual representation model of PTSD. These findings have important clinical implications for cognitive therapy. PMID:25636201

  6. Lateralization of Egocentric and Allocentric Spatial Processing after Parietal Brain Lesions

    ERIC Educational Resources Information Center

    Iachini, Tina; Ruggiero, Gennaro; Conson, Massimiliano; Trojano, Luigi

    2009-01-01

    The purpose of this paper was to verify whether left and right parietal brain lesions may selectively impair egocentric and allocentric processing of spatial information in near/far spaces. Two Right-Brain-Damaged (RBD), 2 Left-Brain-Damaged (LBD) patients (not affected by neglect or language disturbances) and eight normal controls were submitted…

  7. Allocentric spatial learning and memory deficits in Down syndrome.

    PubMed

    Lavenex, Pamela Banta; Bostelmann, Mathilde; Brandner, Catherine; Costanzo, Floriana; Fragnière, Emilie; Klencklen, Giuliana; Lavenex, Pierre; Menghini, Deny; Vicari, Stefano

    2015-01-01

    Studies have shown that persons with Down syndrome (DS) exhibit relatively poor language capacities, and impaired verbal and visuoperceptual memory, whereas their visuospatial memory capacities appear comparatively spared. Individuals with DS recall better where an object was previously seen than what object was previously seen. However, most of the evidence concerning preserved visuospatial memory comes from tabletop or computerized experiments which are biased toward testing egocentric (viewpoint-dependent) spatial representations. Accordingly, allocentric (viewpoint-independent) spatial learning and memory capacities may not be necessary to perform these tasks. Thus, in order to more fully characterize the spatial capacities of individuals with DS, allocentric processes underlying real-world navigation must also be investigated. We tested 20 participants with DS and 16 mental age-matched, typically developing (TD) children in a real-world, allocentric spatial (AS) memory task. During local cue (LC) trials, participants had to locate three rewards marked by local color cues, among 12 locations distributed in a 4 m × 4 m arena. During AS trials, participants had to locate the same three rewards, in absence of LCs, based on their relations to distal environmental cues. All TD participants chose rewarded locations in LC and AS trials at above chance level. In contrast, although all but one of the participants with DS exhibited a preference for the rewarded locations in LC trials, only 50% of participants with DS chose the rewarded locations at above chance level in AS trials. As a group, participants with DS performed worse than TD children on all measures of task performance. These findings demonstrate that individuals with DS are impaired at using an AS representation to learn and remember discrete locations in a controlled environment, suggesting persistent and pervasive deficits in hippocampus-dependent memory in DS. PMID:25762946

  8. Allocentric spatial learning and memory deficits in Down syndrome

    PubMed Central

    Lavenex, Pamela Banta; Bostelmann, Mathilde; Brandner, Catherine; Costanzo, Floriana; Fragnière, Emilie; Klencklen, Giuliana; Lavenex, Pierre; Menghini, Deny; Vicari, Stefano

    2015-01-01

    Studies have shown that persons with Down syndrome (DS) exhibit relatively poor language capacities, and impaired verbal and visuoperceptual memory, whereas their visuospatial memory capacities appear comparatively spared. Individuals with DS recall better where an object was previously seen than what object was previously seen. However, most of the evidence concerning preserved visuospatial memory comes from tabletop or computerized experiments which are biased toward testing egocentric (viewpoint-dependent) spatial representations. Accordingly, allocentric (viewpoint-independent) spatial learning and memory capacities may not be necessary to perform these tasks. Thus, in order to more fully characterize the spatial capacities of individuals with DS, allocentric processes underlying real-world navigation must also be investigated. We tested 20 participants with DS and 16 mental age-matched, typically developing (TD) children in a real-world, allocentric spatial (AS) memory task. During local cue (LC) trials, participants had to locate three rewards marked by local color cues, among 12 locations distributed in a 4 m × 4 m arena. During AS trials, participants had to locate the same three rewards, in absence of LCs, based on their relations to distal environmental cues. All TD participants chose rewarded locations in LC and AS trials at above chance level. In contrast, although all but one of the participants with DS exhibited a preference for the rewarded locations in LC trials, only 50% of participants with DS chose the rewarded locations at above chance level in AS trials. As a group, participants with DS performed worse than TD children on all measures of task performance. These findings demonstrate that individuals with DS are impaired at using an AS representation to learn and remember discrete locations in a controlled environment, suggesting persistent and pervasive deficits in hippocampus-dependent memory in DS. PMID:25762946

  9. Improvement of Allocentric Spatial Memory Resolution in Children from 2 to 4 Years of Age

    ERIC Educational Resources Information Center

    Lambert, Farfalla Ribordy; Lavenex, Pierre; Lavenex, Pamela Banta

    2015-01-01

    Allocentric spatial memory, the memory for locations coded in relation to objects comprising our environment, is a fundamental component of episodic memory and is dependent on the integrity of the hippocampal formation in adulthood. Previous research from different laboratories reported that basic allocentric spatial memory abilities are reliably…

  10. Hippocampal Volume Reduction in Humans Predicts Impaired Allocentric Spatial Memory in Virtual-Reality Navigation

    PubMed Central

    Dzieciol, Anna M.; Gadian, David G.; Jentschke, Sebastian; Doeller, Christian F.; Burgess, Neil; Mishkin, Mortimer

    2015-01-01

    hippocampal integrity in humans is not well documented. We investigated spatial recall using a virtual environment in two groups of patients with hippocampal damage (moderate/severe) and a normal control group. The results showed that patients with severe hippocampal damage are impaired in learning and recalling allocentric spatial information. Furthermore, hippocampal volume reduction impaired allocentric navigation beyond what can be predicted by memory quotient as a widely used measure of general memory function. PMID:26490854

  11. As the world turns: short-term human spatial memory in egocentric and allocentric coordinates.

    PubMed

    Banta Lavenex, Pamela; Lecci, Sandro; Prêtre, Vincent; Brandner, Catherine; Mazza, Christian; Pasquier, Jérôme; Lavenex, Pierre

    2011-05-16

    We aimed to determine whether human subjects' reliance on different sources of spatial information encoded in different frames of reference (i.e., egocentric versus allocentric) affects their performance, decision time and memory capacity in a short-term spatial memory task performed in the real world. Subjects were asked to play the Memory game (a.k.a. the Concentration game) without an opponent, in four different conditions that controlled for the subjects' reliance on egocentric and/or allocentric frames of reference for the elaboration of a spatial representation of the image locations enabling maximal efficiency. We report experimental data from young adult men and women, and describe a mathematical model to estimate human short-term spatial memory capacity. We found that short-term spatial memory capacity was greatest when an egocentric spatial frame of reference enabled subjects to encode and remember the image locations. However, when egocentric information was not reliable, short-term spatial memory capacity was greater and decision time shorter when an allocentric representation of the image locations with respect to distant objects in the surrounding environment was available, as compared to when only a spatial representation encoding the relationships between the individual images, independent of the surrounding environment, was available. Our findings thus further demonstrate that changes in viewpoint produced by the movement of images placed in front of a stationary subject is not equivalent to the movement of the subject around stationary images. We discuss possible limitations of classical neuropsychological and virtual reality experiments of spatial memory, which typically restrict the sensory information normally available to human subjects in the real world. PMID:21237209

  12. Allocentric spatial memory in humans with hippocampal lesions.

    PubMed

    Parslow, David M; Morris, Robin G; Fleminger, Simon; Rahman, Qazi; Abrahams, Sharon; Recce, Michael

    2005-01-01

    An immersive virtual reality (IVR) system was used to investigate allocentric spatial memory in a patient (PR) who had selective hippocampal damage, and also in patients who had undergone unilateral temporal lobectomies (17 right TL and 19 left TL), their performance compared against normal control groups. A human analogue of the Olton [Olton (1979). Hippocampus, space, and memory. Behavioural Brain Science, 2, 315] spatial maze was developed, consisting of a virtual room, a central virtual circular table and an array of radially arranged up-turned 'shells.' The participant had to search these shells in turn in order to find a blue 'cube' that would then 'move' to another location and so on, until all the shells had been target locations. Within-search errors could be made when the participants returned to a previously visited location during a search, and between-search errors when they revisited previously successful, but now incorrect locations. PR made significantly more between-search errors than his control group, but showed no increase in within-search errors. The right TL group showed a similar pattern of impairment, but the left TL group showed no impairment. This finding implicates the right hippocampal formation in spatial memory functioning in a scenario in which the visual environment was controlled so as to eliminate extraneous visual cues. PMID:15627413

  13. Allocentric Spatial Performance Higher in Early-Blind and Sighted Adults Than in Retinopathy-of-Prematurity Adults.

    PubMed

    Eardley, Alison F; Edwards, Geoffrey; Malouin, Francine; Kennedy, John M

    2016-03-01

    The question as to whether people totally blind since infancy process allocentric or external spatial information like the sighted has caused considerable debate within the literature. Due to the extreme rarity of the population, researchers have often included individuals with retinopathy of prematurity (RoP--over oxygenation at birth) within the sample. However, RoP is inextricably confounded with prematurity per se. Prematurity, without visual disability, has been associated with spatial processing difficulties. In this experiment, blindfolded sighted participants and two groups of functionally totally blind participants heard text descriptions from a survey (allocentric) or route (egocentric) perspective. One blind group lost their sight due to RoP and a second group before 24 months of age. The accuracy of participants' mental representations derived from the text descriptions was assessed via questions and maps. The RoP participants had lower scores than the sighted and early blind, who performed similarly. In other words, it was not visual impairment alone that resulted in impaired allocentric spatial performance in this task but visual impairment together with RoP. This finding may help explain the contradictions within the existing literature on the role of vision in allocentric spatial processing. PMID:26562868

  14. Acute stress switches spatial navigation strategy from egocentric to allocentric in a virtual Morris water maze.

    PubMed

    van Gerven, Dustin J H; Ferguson, Thomas; Skelton, Ronald W

    2016-07-01

    Stress and stress hormones are known to influence the function of the hippocampus, a brain structure critical for cognitive-map-based, allocentric spatial navigation. The caudate nucleus, a brain structure critical for stimulus-response-based, egocentric navigation, is not as sensitive to stress. Evidence for this comes from rodent studies, which show that acute stress or stress hormones impair allocentric, but not egocentric navigation. However, there have been few studies investigating the effect of acute stress on human spatial navigation, and the results of these have been equivocal. To date, no study has investigated whether acute stress can shift human navigational strategy selection between allocentric and egocentric navigation. The present study investigated this question by exposing participants to an acute psychological stressor (the Paced Auditory Serial Addition Task, PASAT), before testing navigational strategy selection in the Dual-Strategy Maze, a modified virtual Morris water maze. In the Dual-Strategy maze, participants can chose to navigate using a constellation of extra-maze cues (allocentrically) or using a single cue proximal to the goal platform (egocentrically). Surprisingly, PASAT stress biased participants to solve the maze allocentrically significantly more, rather than less, often. These findings have implications for understanding the effects of acute stress on cognitive function in general, and the function of the hippocampus in particular. PMID:27174311

  15. Cerebellar allocentric and action-intentional spatial neglect.

    PubMed

    Milano, Nicholas J; Heilman, Kenneth M

    2014-09-01

    Contralesional hemispatial neglect most often results from lesions in the right posterior temporoparietal cortex. Less commonly, contralesional and ipsilesional neglect are caused by lesions in the frontal lobe. Although unilateral left cerebellar lesions have been reported to cause body-centered (egocentric) ipsilesional neglect, they have not been reported to cause left-side object-centered (allocentric) neglect together with a leftward action-intentional bias. We describe a patient who had these signs of neglect 7 months after a left cerebellar hemorrhage. This 61-year-old right-handed woman reported emotional lability and difficulty walking, frequently bumping into things on her left side. Neurologic examination revealed ocular dysmetria and left-side limb ataxia. Neuropsychological tests showed evidence of neglect. On a clock-drawing test, the patient accurately drew a circle but her number placement deviated to the left side. She showed the same leftward deviation when she tried to draw a circle composed of small triangles. Although her line bisection was normal, on an allocentric task of open-triangle cancellation she was most likely to neglect triangles with a left-side opening. Her performance on this task indicated left allocentric neglect. Her leftward deviation on the clock and figure drawing tasks seems to be a form of an action-intentional grasp, which may have been induced by right frontal dysfunction superimposed on a deficit of global attention. PMID:25237748

  16. Development of Allocentric Spatial Memory Abilities in Children from 18 months to 5 Years of Age

    ERIC Educational Resources Information Center

    Ribordy, Farfalla; Jabes, Adeline; Lavenex, Pamela Banta; Lavenex, Pierre

    2013-01-01

    Episodic memories for autobiographical events that happen in unique spatiotemporal contexts are central to defining who we are. Yet, before 2 years of age, children are unable to form or store episodic memories for recall later in life, a phenomenon known as infantile amnesia. Here, we studied the development of allocentric spatial memory, a…

  17. How coordinate and categorical spatial relations combine with egocentric and allocentric reference frames in a motor task: effects of delay and stimuli characteristics.

    PubMed

    Ruotolo, Francesco; van der Ham, Ineke; Postma, Albert; Ruggiero, Gennaro; Iachini, Tina

    2015-05-01

    This study explores how people represent spatial information in order to accomplish a visuo-motor task. To this aim we combined two fundamental components of the human visuo-spatial system: egocentric and allocentric frames of reference and coordinate and categorical spatial relations. Specifically, participants learned the position of three objects and then had to judge the distance (coordinate information) and the relation (categorical information) of a target object with respect to themselves (egocentric frame) or with respect to another object (allocentric frame). They gave spatial judgments by reaching and touching the exact position or the side previously occupied by the target object. The possible influence of stimuli characteristics (3D objects vs. 2D images) and delay between learning phase and testing phase (1.5 vs. 5s) was also assessed. Results showed an advantage of egocentric coordinate judgments over the allocentric coordinate ones independently from the kind of stimuli used and the temporal parameters of the response, whereas egocentric categorical judgments were more accurate than allocentric categorical ones only with 3D stimuli and when an immediate response was requested. This pattern of data is discussed in the light of the "perception-action" model by Milner and Goodale [13] and of neuroimaging evidence about frames of reference and spatial relations. PMID:25698602

  18. A critical review of the allocentric spatial representation and its neural underpinnings: toward a network-based perspective

    PubMed Central

    Ekstrom, Arne D.; Arnold, Aiden E. G. F.; Iaria, Giuseppe

    2014-01-01

    While the widely studied allocentric spatial representation holds a special status in neuroscience research, its exact nature and neural underpinnings continue to be the topic of debate, particularly in humans. Here, based on a review of human behavioral research, we argue that allocentric representations do not provide the kind of map-like, metric representation one might expect based on past theoretical work. Instead, we suggest that almost all tasks used in past studies involve a combination of egocentric and allocentric representation, complicating both the investigation of the cognitive basis of an allocentric representation and the task of identifying a brain region specifically dedicated to it. Indeed, as we discuss in detail, past studies suggest numerous brain regions important to allocentric spatial memory in addition to the hippocampus, including parahippocampal, retrosplenial, and prefrontal cortices. We thus argue that although allocentric computations will often require the hippocampus, particularly those involving extracting details across temporally specific routes, the hippocampus is not necessary for all allocentric computations. We instead suggest that a non-aggregate network process involving multiple interacting brain areas, including hippocampus and extra-hippocampal areas such as parahippocampal, retrosplenial, prefrontal, and parietal cortices, better characterizes the neural basis of spatial representation during navigation. According to this model, an allocentric representation does not emerge from the computations of a single brain region (i.e., hippocampus) nor is it readily decomposable into additive computations performed by separate brain regions. Instead, an allocentric representation emerges from computations partially shared across numerous interacting brain regions. We discuss our non-aggregate network model in light of existing data and provide several key predictions for future experiments. PMID:25346679

  19. Are All Spatial Reference Frames Egocentric? Reinterpreting Evidence for Allocentric, Object-Centered, or World-Centered Reference Frames

    PubMed Central

    Filimon, Flavia

    2015-01-01

    The use and neural representation of egocentric spatial reference frames is well-documented. In contrast, whether the brain represents spatial relationships between objects in allocentric, object-centered, or world-centered coordinates is debated. Here, I review behavioral, neuropsychological, neurophysiological (neuronal recording), and neuroimaging evidence for and against allocentric, object-centered, or world-centered spatial reference frames. Based on theoretical considerations, simulations, and empirical findings from spatial navigation, spatial judgments, and goal-directed movements, I suggest that all spatial representations may in fact be dependent on egocentric reference frames. PMID:26696861

  20. Standardized norm data for three self-report scales on egocentric and allocentric environmental spatial strategies.

    PubMed

    Münzer, Stefan; Fehringer, Benedict C O F; Kühl, Tim

    2016-09-01

    Standardized norm data for three scales of a 19-item self-report measure on environmental spatial strategies are provided. This self-report measure comprises egocentric spatial strategies, an allocentric mental map strategy and knowledge of cardinal directions as three separate scales, "Validation of a 3-factor structure of spatial strategies and relations to possession and usage of navigational aids" (Münzer et al., 2016) [3]. The data are based on a large sample (N>4000) representative for the population in Germany. Standardized norm data for men and women in different age groups are provided through percentile ranks and T-values. PMID:27500192

  1. Development of egocentric and allocentric spatial representations from childhood to elderly age.

    PubMed

    Ruggiero, Gennaro; D'Errico, Ortensia; Iachini, Tina

    2016-03-01

    Spatial reference frames are fundamental to represent the position of objects or places. Although research has reported changes in spatial memory abilities during childhood and elderly age, no study has assessed reference frames processing during the entire lifespan using the same task. Here, we aimed at providing some preliminary data on the capacity to process reference frames in 283 healthy participants from 6 to 89 years of age. A spatial memory task requiring egocentric/allocentric verbal judgments about objects in peri-/extrapersonal space was used. The main goals were: (1) tracing a baseline of the normal process of development of these spatial components; (2) clarifying if reference frames are differently vulnerable to age-related effects. Results showed a symmetry between children of 6-7 years and older people of 80-89 years who were slower and less accurate than all other age groups. As regards processing time, age had a strong effect on the allocentric component, especially in extrapersonal space, with a longer time in 6- to 7-year-old children and 80- to 89-year-old adults. The egocentric component looked less affected by aging. Regarding the level of spatial ability (accuracy), the allocentric ability appeared less sensitive to age-related variations, whereas the egocentric ability progressively improved from 8 years and declined from 60 years. The symmetry in processing time and level of spatial ability is discussed in relation to the development of executive functions and to the structural and functional changes due to incomplete maturation (in youngest children) and deterioration (in oldest adults) of underlying cerebral areas. PMID:25805435

  2. Functional Equivalence of Spatial Representations Derived From Vision and Language: Evidence From Allocentric Judgments

    ERIC Educational Resources Information Center

    Avraamides, Marios N.; Loomis, Jack M.; Klatzky, Roberta L.; Golledge, Reginald G.

    2004-01-01

    Past research (e.g., J. M. Loomis, Y. Lippa, R. L. Klatzky, & R. G. Golledge, 2002) has indicated that spatial representations derived from spatial language can function equivalently to those derived from perception. The authors tested functional equivalence for reporting spatial relations that were not explicitly stated during learning.…

  3. Roles of Egocentric and Allocentric Spatial Representations in Locomotion and Reorientation

    ERIC Educational Resources Information Center

    Mou, Weimin; McNamara, Timothy P.; Rump, Bjorn; Xiao, Chengli

    2006-01-01

    Four experiments investigated the nature of spatial representations used in locomotion. Participants learned the layout of several objects and then pointed to the objects while blindfolded in 3 conditions: before turning (baseline), after turning to a new heading (updating), and after disorientation (disorientation). The internal consistency of…

  4. Mental "Space" Travel: Damage to Posterior Parietal Cortex Prevents Egocentric Navigation and Reexperiencing of Remote Spatial Memories

    ERIC Educational Resources Information Center

    Ciaramelli, Elisa; Rosenbaum, R. Shayna; Solcz, Stephanie; Levine, Brian; Moscovitch, Morris

    2010-01-01

    The ability to navigate in a familiar environment depends on both an intact mental representation of allocentric spatial information and the integrity of systems supporting complementary egocentric representations. Although the hippocampus has been implicated in learning new allocentric spatial information, converging evidence suggests that the…

  5. A Study on the Role of the Dorsal Striatum and the Nucleus Accumbens in Allocentric and Egocentric Spatial Memory Consolidation

    ERIC Educational Resources Information Center

    De Leonibus, Elvira; Oliverio, Alberto; Mele, Andrea

    2005-01-01

    There is now accumulating evidence that the striatal complex in its two major components, the dorsal striatum and the nucleus accumbens, contributes to spatial memory. However, the possibility that different striatal subregions might modulate specific aspects of spatial navigation has not been completely elucidated. Therefore, in this study, two…

  6. The Simon effect based on the egocentric and allocentric reference frame.

    PubMed

    Wang, Huan; Liu, Nan; Zou, Guiying; Li, Hui; Zeng, Hang; Chen, Jiedan; Chen, Qi

    2016-02-01

    The classic Simon effect refers to the phenomenon that responses are faster when the task-irrelevant egocentric stimulus location is on the same side as the response hand than when not. However, the spatial location of an object often varies according to which reference frame the object location was represented in, e.g., egocentric versus allocentric reference frame. It has been unknown, however, whether and how the Simon effect based on the egocentric and the allocentric reference interact, and whether the potential interaction between them is affected by task demands. To investigate these questions, we orthogonally crossed the stimulus-response compatibility induced by the egocentric and the allocentric positions during the Simon effect. Moreover, the irrelevant egocentric and allocentric positions were either explicitly represented via interleaving spatial and non-spatial tasks in Experiment 1 or not in Experiment 2. The results suggested that the Simon effect based on the egocentric locations occurred irrespective of whether the egocentric representations were explicitly coded based on current task demands or not. The Simon effect based on allocentric locations, however, seemed to occur only when the allocentric representations were explicitly induced. Moreover, the egocentric and allocentric Simon effect interacted in a similar way irrespective of task demands, with significantly delayed responses when both the egocentric and the allocentric locations were incongruent with the response code. PMID:26603042

  7. Spatial encoding of hidden objects in dogs (Canis familiaris).

    PubMed

    Fiset, S; Gagnon, S; Beaulieu, C

    2000-12-01

    The authors investigated the type of spatial information that controls domestic dogs' (Canis familiaris) search behavior in a situation in which they have to locate a spatial position where they saw an object move and disappear. In Experiments 1 and 2, the authors manipulated all local and global sources of allocentric spatial information surrounding the hiding location. The results revealed that dogs relied on an egocentric frame of reference. Experiment 3 showed that dogs also encoded allocentric information when egocentric information was irrelevant. The authors conclude that dogs simultaneously encode both egocentric and allocentric spatial information to locate a spatial position, but they primarily base their search behavior on an egocentric frame of reference. The authors discuss under which natural conditions dogs might use these 2 sources of spatial information and detail the nature of spatial egocentric information and the circumstances underlying its use by dogs. PMID:11149535

  8. The role of egocentric and allocentric abilities in Alzheimer's disease: a systematic review.

    PubMed

    Serino, Silvia; Cipresso, Pietro; Morganti, Francesca; Riva, Giuseppe

    2014-07-01

    A great effort has been made to identify crucial cognitive markers that can be used to characterize the cognitive profile of Alzheimer's disease (AD). Because topographical disorientation is one of the earliest clinical manifestation of AD, an increasing number of studies have investigated the spatial deficits in this clinical population. In this systematic review, we specifically focused on experimental studies investigating allocentric and egocentric deficits to understand which spatial cognitive processes are differentially impaired in the different stages of the disease. First, our results highlighted that spatial deficits appear in the earliest stages of the disease. Second, a need for a more ecological assessment of spatial functions will be presented. Third, our analysis suggested that a prevalence of allocentric impairment exists. Specifically, two selected studies underlined that a more specific impairment is found in the translation between the egocentric and allocentric representations. In this perspective, the implications for future research and neurorehabilitative interventions will be discussed. PMID:24943907

  9. Interaction between allocentric and egocentric reference frames in deaf and hearing populations.

    PubMed

    Zhang, Ming; Tan, Xinyi; Shen, Lu; Wang, Aijun; Geng, Shuang; Chen, Qi

    2014-02-01

    Spatial position of an object can be represented in the human brain based on two types of reference frames: allocentric and egocentric. The perception/action hypothesis of the ventral/dorsal visual stream proposed that allocentric reference frame codes object positions relative to another object/background subserving conscious perception of the external world while egocentric reference frame codes object positions relative to the observer's body/body parts subserving goal-directed actions towards the objects. In three experiments of the present study, by asking congenitally deaf participants and hearing controls to perform allocentric and egocentric judgment tasks on the same stimulus set and by using the spatial congruency effect between allocentric and egocentric positions of the same target object to indicate the extent of influences between the two frames, we aimed to investigate whether the two frames and the potential interaction between them are altered after early deafness. Our results suggested that deaf participants' responses were significantly slower in the egocentric tasks as compared to hearing controls while the two groups showed comparable task performance in the allocentric tasks, indicating that egocentric reference frame was impaired after early deafness. Moreover, the pattern of interaction between the two frames was different between deaf and hearing groups: irrelevant egocentric positions caused more interference to allocentric processing than vice versa in the hearing group while the two frames caused equivalent interference to each other in the deaf group. Further control experiments suggested that the above effects were not caused by the impaired sense of balance in the congenitally deaf participants (via open-loop pointing test), and was independent of whether the speed of allocentric and egocentric processing was equivalent or not in the hearing group. PMID:24361477

  10. Spatial memory of domestic dogs (Canis familiaris) for hidden objects in a detour task.

    PubMed

    Fiset, Sylvain; Beaulieu, Claude; LeBlanc, Valérie; Dubé, Lucie

    2007-10-01

    Spatial memory of domestic dogs (Canis familiaris) for hidden objects was investigated via a visible displacement problem of object permanence with a detour paradigm. Experiment 1 showed that dogs were able to spontaneously locate a disappearing object in a detour situation. In Experiments 2 and 3, dead reckoning and allocentric spatial information were put in conflict. Results revealed that dogs simultaneously encoded both sources of information when they had to bypass an obstacle to locate a hidden object. Experiment 3 also revealed that, over the course of testing, dogs gradually learned to rely predominantly on allocentric cues when the detour involved several reorientations. The current study reveals that spatial memory of dogs for hidden objects in a detour task was guided by flexibility in processing spatial information. Dogs could simultaneously encode dead reckoning and allocentric information to locate a disappearing object and used them hierarchically according to the complexity of the detour they encountered in the environment. PMID:17924796

  11. Frames of reference and categorical/coordinate spatial relations in a "what was where" task.

    PubMed

    Ruotolo, Francesco; Iachini, Tina; Ruggiero, Gennaro; van der Ham, Ineke J M; Postma, Albert

    2016-09-01

    The aim of this study was to explore how people use egocentric (i.e., with respect to their body) and allocentric (i.e., with respect to another element in the environment) references in combination with coordinate (metric) or categorical (abstract) spatial information to identify a target element. Participants were asked to memorize triads of 3D objects or 2D figures, and immediately or after a delay of 5 s, they had to verbally indicate what was the object/figure: (1) closest/farthest to them (egocentric coordinate task); (2) on their right/left (egocentric categorical task); (3) closest/farthest to another object/figure (allocentric coordinate task); (4) on the right/left of another object/figure (allocentric categorical task). Results showed that the use of 2D figures favored categorical judgments over the coordinate ones with either an egocentric or an allocentric reference frame, whereas the use of 3D objects specifically favored egocentric coordinate judgments rather than the allocentric ones. Furthermore, egocentric judgments were more accurate than allocentric judgments when the response was Immediate rather than delayed and 3D objects rather than 2D figures were used. This pattern of results is discussed in the light of the functional roles attributed to the frames of reference and spatial relations by relevant theories of visuospatial processing. PMID:27180248

  12. Individual Differences in the Encoding Processes of Egocentric and Allocentric Survey Knowledge

    ERIC Educational Resources Information Center

    Wen, Wen; Ishikawa, Toru; Sato, Takao

    2013-01-01

    This study examined how different components of working memory are involved in the acquisition of egocentric and allocentric survey knowledge by people with a good and poor sense of direction (SOD). We employed a dual-task method and asked participants to learn routes from videos with verbal, visual, and spatial interference tasks and without any…

  13. Developmental Time Course of the Acquisition of Sequential Egocentric and Allocentric Navigation Strategies

    ERIC Educational Resources Information Center

    Bullens, Jessie; Igloi, Kinga; Berthoz, Alain; Postma, Albert; Rondi-Reig, Laure

    2010-01-01

    Navigation in a complex environment can rely on the use of different spatial strategies. We have focused on the employment of "allocentric" (i.e., encoding interrelationships among environmental cues, movements, and the location of the goal) and "sequential egocentric" (i.e., sequences of body turns associated with specific choice points)…

  14. Cognitive allocentric representations of visual space shape pointing errors.

    PubMed

    Carrozzo, M; Stratta, F; McIntyre, J; Lacquaniti, F

    2002-12-01

    Subjects reached in three-dimensional space to a set of remembered targets whose position was varied randomly from trial to trial, but always fell along a "virtual" line (line condition). Targets were presented briefly, one-by-one and in an empty visual field. After a short delay, subjects were required to point to the remembered target location. Under these conditions, the target was presented in the complete absence of allocentric visual cues as to its position in space. However, because the subjects were informed prior to the experiment that all targets would fall on a straight line, they could conceivably imagine each point target as belonging to a single rigid object with a particular geometry and orientation in space, although this virtual object was never explicitly shown to the subjects. We compared the responses to repeated measurements of each target with those measured for targets presented in a directionally neutral configuration (sphere condition), and used the variable errors to infer the putative reference frames underlying the corresponding sensorimotor transformation. Performance in the different tasks was compared under two different lighting conditions (dim light or total darkness) and two memory delays (0.5 or 5 s). The pattern of variable errors differed significantly between the sphere condition and the line condition. In the former case, the errors were always accounted for by egocentric reference frames. By contrast the errors in the line condition revealed both egocentric and allocentric components, consistent with the hypothesis that target information can be defined concurrently in both egocentric and allocentric frames of reference, resulting in two independent coexisting representations. PMID:12444474

  15. Egocentric and Allocentric Localization During Induced Motion

    PubMed Central

    Post, Robert B.; Welch, Robert B.; Whitney, David

    2009-01-01

    This research examined motor measures of the apparent egocentric location and perceptual measures of the apparent allocentric location of a target that was being seen to undergo induced motion (IM). In Experiments 1 and 3, subjects fixated a stationary dot (IM target) while a rectangular surround stimulus (inducing stimulus) oscillated horizontally. The inducing stimulus motion caused the IM target to appear to move in the opposite direction. In Experiment 1, two dots (flashed targets) were flashed above and below the IM target when the surround had reached its leftmost or rightmost displacement from the subject’s midline. Subjects pointed open loop at either the apparent egocentric location of the IM target or at the bottom of the two flashed targets. On separate trials, subjects made judgments of the Vernier alignment of the IM target with the flashed targets at the endpoints of the surround’s oscillation. The pointing responses were displaced in the direction of the previously seen IM for the IM target and to a lesser degree for the bottom flashed target. However, the allocentric Vernier judgments demonstrated no perceptual displacement of the IM target relative to the flashed targets. Thus, IM results in a dissociation of egocentric location measures from allocentric location measures. In Experiment 2, pointing and Vernier measures were obtained with stationary horizontally displaced surrounds and there was no dissociation of egocentric location measures from allocentric location measures. These results indicate that the Roelofs effect did not produce the pattern of results in Experiment 1. In Experiment 3, pointing and Vernier measures were obtained when the surround was at the midpoint of an oscillation. In this case, egocentric pointing responses were displaced in the direction of surround motion (opposite IM) for the IM target and to a greater degree for the bottom flashed target. However, there was no apparent displacement of the IM target relative to

  16. Allocentric kin recognition is not affected by facial inversion

    PubMed Central

    Dal Martello, Maria F.; DeBruine, Lisa M.; Maloney, Laurence T.

    2015-01-01

    Typical judgments involving faces are disrupted by inversion, with the Thatcher illusion serving as a compelling example. In two experiments, we examined how inversion affects allocentric kin recognition—the ability to judge the degree of genetic relatedness of others. In the first experiment, participants judged whether pairs of photographs of children portrayed siblings or unrelated children. Half of the pairs were siblings, half were unrelated. In three experimental conditions, photographs were viewed in upright orientation, flipped around a horizontal axis, or rotated 180°. Neither rotation nor flipping had any detectable effect on allocentric kin recognition. In the second experiment, participants judged pairs of photographs of adult women. Half of the pairs were sisters, half were unrelated. We again found no significant effect of facial inversion. Unlike almost all other face judgments, judgments of kinship from facial appearance do not rely on perceptual cues disrupted by inversion, suggesting that they rely more on spatially localized cues rather than “holistic” cues. We conclude that kin recognition is not simply a byproduct of other face perception abilities. We discuss the implications for cue combination models of other facial judgments that are affected by inversion. PMID:26381836

  17. EEG correlates of spatial orientation in the human retrosplenial complex.

    PubMed

    Lin, C-T; Chiu, T-C; Gramann, K

    2015-10-15

    Studies on spatial navigation reliably demonstrate that the retrosplenial complex (RSC) plays a pivotal role for allocentric spatial information processing by transforming egocentric and allocentric spatial information into the respective other spatial reference frame (SRF). While more and more imaging studies investigate the role of the RSC in spatial tasks, high temporal resolution measures such as electroencephalography (EEG) are missing. To investigate the function of the RSC in spatial navigation with high temporal resolution we used EEG to analyze spectral perturbations during navigation based on allocentric and egocentric SRF. Participants performed a path integration task in a clearly structured virtual environment providing allothetic information. Continuous EEG recordings were decomposed by independent component analysis (ICA) with subsequent source reconstruction of independent time source series using equivalent dipole modeling. Time-frequency transformation was used to investigate reference frame-specific orientation processes during navigation as compared to a control condition with identical visual input but no orientation task. Our results demonstrate that navigation based on an egocentric reference frame recruited a network including the parietal, motor, and occipital cortices with dominant perturbations in the alpha band and theta modulation in frontal cortex. Allocentric navigation was accompanied by performance-related desynchronization of the 8-13 Hz frequency band and synchronization in the 12-14 Hz band in the RSC. The results support the claim that the retrosplenial complex is central to translating egocentric spatial information into allocentric reference frames. Modulations in different frequencies with different time courses in the RSC further provide first evidence of two distinct neural processes reflecting translation of spatial information based on distinct reference frames and the computation of heading changes. PMID:26163801

  18. Phenomenal Consciousness and the Allocentric-Egocentric Interface

    NASA Astrophysics Data System (ADS)

    Mandik, Pete

    2005-10-01

    I propose and defend the Allocentric-Egocentric Interface Theory of Consciousness. Mental processes form a hierarchy of mental representations with maximally egocentric (self-centered) representations at the bottom and maximally allocentric (other-centered) representations at the top. Phenomenally conscious states are states that are relatively intermediate in this hierarchy. More specifically, conscious states are hybrid states that involve the reciprocal interaction between relatively allocentric and relatively egocentric representations. Thus a conscious state is composed of a pair of representations interacting at the Allocentric-Egocentric Interface. What a person is conscious of is determined by what the contributing allocentric and egocentric representations are representations of. The phenomenal character of conscious states is identical to the representational content of the reciprocally interacting egocentric and allocentric representations.

  19. Spatial representations of place cells in darkness are supported by path integration and border information

    PubMed Central

    Zhang, Sijie; Schönfeld, Fabian; Wiskott, Laurenz; Manahan-Vaughan, Denise

    2014-01-01

    Effective spatial navigation is enabled by reliable reference cues that derive from sensory information from the external environment, as well as from internal sources such as the vestibular system. The integration of information from these sources enables dead reckoning in the form of path integration. Navigation in the dark is associated with the accumulation of errors in terms of perception of allocentric position and this may relate to error accumulation in path integration. We assessed this by recording from place cells in the dark under circumstances where spatial sensory cues were suppressed. Spatial information content, spatial coherence, place field size, and peak and infield firing rates decreased whereas sparsity increased following exploration in the dark compared to the light. Nonetheless it was observed that place field stability in darkness was sustained by border information in a subset of place cells. To examine the impact of encountering the environment’s border on navigation, we analyzed the trajectory and spiking data gathered during navigation in the dark. Our data suggest that although error accumulation in path integration drives place field drift in darkness, under circumstances where border contact is possible, this information is integrated to enable retention of spatial representations. PMID:25009477

  20. Spatial Information of Sound Fields

    NASA Astrophysics Data System (ADS)

    Oikawa, Yasuhiro

    The nature of a sound field can only be fully understood when we have spatial information about it. Being able to visualize a sound field is a very useful way of understanding it. This section describes how to estimate many direction of arrivals (DOAs) by using two microphones, how to get spatial information by using four closely located microphones, and how to visualize and measure sound fields by using a laser Doppler vibrometer (LVB).

  1. Entropy, complexity, and spatial information

    NASA Astrophysics Data System (ADS)

    Batty, Michael; Morphet, Robin; Masucci, Paolo; Stanilov, Kiril

    2014-10-01

    We pose the central problem of defining a measure of complexity, specifically for spatial systems in general, city systems in particular. The measures we adopt are based on Shannon's (in Bell Syst Tech J 27:379-423, 623-656, 1948) definition of information. We introduce this measure and argue that increasing information is equivalent to increasing complexity, and we show that for spatial distributions, this involves a trade-off between the density of the distribution and the number of events that characterize it; as cities get bigger and are characterized by more events—more places or locations, information increases, all other things being equal. But sometimes the distribution changes at a faster rate than the number of events and thus information can decrease even if a city grows. We develop these ideas using various information measures. We first demonstrate their applicability to various distributions of population in London over the last 100 years, then to a wider region of London which is divided into bands of zones at increasing distances from the core, and finally to the evolution of the street system that characterizes the built-up area of London from 1786 to the present day. We conclude by arguing that we need to relate these measures to other measures of complexity, to choose a wider array of examples, and to extend the analysis to two-dimensional spatial systems.

  2. Entropy, complexity, and spatial information

    NASA Astrophysics Data System (ADS)

    Batty, Michael; Morphet, Robin; Masucci, Paolo; Stanilov, Kiril

    2014-09-01

    We pose the central problem of defining a measure of complexity, specifically for spatial systems in general, city systems in particular. The measures we adopt are based on Shannon's (in Bell Syst Tech J 27:379-423, 623-656, 1948) definition of information. We introduce this measure and argue that increasing information is equivalent to increasing complexity, and we show that for spatial distributions, this involves a trade-off between the density of the distribution and the number of events that characterize it; as cities get bigger and are characterized by more events—more places or locations, information increases, all other things being equal. But sometimes the distribution changes at a faster rate than the number of events and thus information can decrease even if a city grows. We develop these ideas using various information measures. We first demonstrate their applicability to various distributions of population in London over the last 100 years, then to a wider region of London which is divided into bands of zones at increasing distances from the core, and finally to the evolution of the street system that characterizes the built-up area of London from 1786 to the present day. We conclude by arguing that we need to relate these measures to other measures of complexity, to choose a wider array of examples, and to extend the analysis to two-dimensional spatial systems.

  3. Visual attention modulates the asymmetric influence of each cerebral hemisphere on spatial perception.

    PubMed

    Wang, Meijian; Wang, Xiuhai; Xue, Lingyan; Huang, Dan; Chen, Yao

    2016-01-01

    Although the allocation of brain functions across the two cerebral hemispheres has aroused public interest over the past century, asymmetric interhemispheric cooperation under attentional modulation has been scarcely investigated. An example of interhemispheric cooperation is visual spatial perception. During this process, visual information from each hemisphere is integrated because each half of the visual field predominantly projects to the contralateral visual cortex. Both egocentric and allocentric coordinates can be employed for visual spatial representation, but they activate different areas in primate cerebral hemispheres. Recent studies have determined that egocentric representation affects the reaction time of allocentric perception; furthermore, this influence is asymmetric between the two visual hemifields. The egocentric-allocentric incompatibility effect and its asymmetry between the two hemispheres can produce this phenomenon. Using an allocentric position judgment task, we found that this incompatibility effect was reduced, and its asymmetry was eliminated on an attentional task rather than a neutral task. Visual attention might activate cortical areas that process conflicting information, such as the anterior cingulate cortex, and balance the asymmetry between the two hemispheres. Attention may enhance and balance this interhemispheric cooperation because this imbalance may also be caused by the asymmetric cooperation of each hemisphere in spatial perception. PMID:26758349

  4. Visual attention modulates the asymmetric influence of each cerebral hemisphere on spatial perception

    PubMed Central

    Wang, Meijian; Wang, Xiuhai; Xue, Lingyan; Huang, Dan; Chen, Yao

    2016-01-01

    Although the allocation of brain functions across the two cerebral hemispheres has aroused public interest over the past century, asymmetric interhemispheric cooperation under attentional modulation has been scarcely investigated. An example of interhemispheric cooperation is visual spatial perception. During this process, visual information from each hemisphere is integrated because each half of the visual field predominantly projects to the contralateral visual cortex. Both egocentric and allocentric coordinates can be employed for visual spatial representation, but they activate different areas in primate cerebral hemispheres. Recent studies have determined that egocentric representation affects the reaction time of allocentric perception; furthermore, this influence is asymmetric between the two visual hemifields. The egocentric-allocentric incompatibility effect and its asymmetry between the two hemispheres can produce this phenomenon. Using an allocentric position judgment task, we found that this incompatibility effect was reduced, and its asymmetry was eliminated on an attentional task rather than a neutral task. Visual attention might activate cortical areas that process conflicting information, such as the anterior cingulate cortex, and balance the asymmetry between the two hemispheres. Attention may enhance and balance this interhemispheric cooperation because this imbalance may also be caused by the asymmetric cooperation of each hemisphere in spatial perception. PMID:26758349

  5. Basal Forebrain Atrophy Contributes to Allocentric Navigation Impairment in Alzheimer’s Disease Patients

    PubMed Central

    Kerbler, Georg M.; Nedelska, Zuzana; Fripp, Jurgen; Laczó, Jan; Vyhnalek, Martin; Lisý, Jiří; Hamlin, Adam S.; Rose, Stephen; Hort, Jakub; Coulson, Elizabeth J.

    2015-01-01

    The basal forebrain degenerates in Alzheimer’s disease (AD) and this process is believed to contribute to the cognitive decline observed in AD patients. Impairment in spatial navigation is an early feature of the disease but whether basal forebrain dysfunction in AD is responsible for the impaired navigation skills of AD patients is not known. Our objective was to investigate the relationship between basal forebrain volume and performance in real space as well as computer-based navigation paradigms in an elderly cohort comprising cognitively normal controls, subjects with amnestic mild cognitive impairment and those with AD. We also tested whether basal forebrain volume could predict the participants’ ability to perform allocentric- vs. egocentric-based navigation tasks. The basal forebrain volume was calculated from 1.5 T magnetic resonance imaging (MRI) scans, and navigation skills were assessed using the human analog of the Morris water maze employing allocentric, egocentric, and mixed allo/egocentric real space as well as computerized tests. When considering the entire sample, we found that basal forebrain volume correlated with spatial accuracy in allocentric (cued) and mixed allo/egocentric navigation tasks but not the egocentric (uncued) task, demonstrating an important role of the basal forebrain in mediating cue-based spatial navigation capacity. Regression analysis revealed that, although hippocampal volume reflected navigation performance across the entire sample, basal forebrain volume contributed to mixed allo/egocentric navigation performance in the AD group, whereas hippocampal volume did not. This suggests that atrophy of the basal forebrain contributes to aspects of navigation impairment in AD that are independent of hippocampal atrophy. PMID:26441643

  6. Basal Forebrain Atrophy Contributes to Allocentric Navigation Impairment in Alzheimer's Disease Patients.

    PubMed

    Kerbler, Georg M; Nedelska, Zuzana; Fripp, Jurgen; Laczó, Jan; Vyhnalek, Martin; Lisý, Jiří; Hamlin, Adam S; Rose, Stephen; Hort, Jakub; Coulson, Elizabeth J

    2015-01-01

    The basal forebrain degenerates in Alzheimer's disease (AD) and this process is believed to contribute to the cognitive decline observed in AD patients. Impairment in spatial navigation is an early feature of the disease but whether basal forebrain dysfunction in AD is responsible for the impaired navigation skills of AD patients is not known. Our objective was to investigate the relationship between basal forebrain volume and performance in real space as well as computer-based navigation paradigms in an elderly cohort comprising cognitively normal controls, subjects with amnestic mild cognitive impairment and those with AD. We also tested whether basal forebrain volume could predict the participants' ability to perform allocentric- vs. egocentric-based navigation tasks. The basal forebrain volume was calculated from 1.5 T magnetic resonance imaging (MRI) scans, and navigation skills were assessed using the human analog of the Morris water maze employing allocentric, egocentric, and mixed allo/egocentric real space as well as computerized tests. When considering the entire sample, we found that basal forebrain volume correlated with spatial accuracy in allocentric (cued) and mixed allo/egocentric navigation tasks but not the egocentric (uncued) task, demonstrating an important role of the basal forebrain in mediating cue-based spatial navigation capacity. Regression analysis revealed that, although hippocampal volume reflected navigation performance across the entire sample, basal forebrain volume contributed to mixed allo/egocentric navigation performance in the AD group, whereas hippocampal volume did not. This suggests that atrophy of the basal forebrain contributes to aspects of navigation impairment in AD that are independent of hippocampal atrophy. PMID:26441643

  7. Spatial Representation of Ordinal Information

    PubMed Central

    Zhang, Meng; Gao, Xuefei; Li, Baichen; Yu, Shuyuan; Gong, Tianwei; Jiang, Ting; Hu, Qingfen; Chen, Yinghe

    2016-01-01

    Right hand responds faster than left hand when shown larger numbers and vice-versa when shown smaller numbers (the SNARC effect). Accumulating evidence suggests that the SNARC effect may not be exclusive for numbers and can be extended to other ordinal sequences (e.g., months or letters in the alphabet) as well. In this study, we tested the SNARC effect with a non-numerically ordered sequence: the Chinese notations for the color spectrum (Red, Orange, Yellow, Green, Blue, Indigo, and Violet). Chinese color word sequence reserves relatively weak ordinal information, because each element color in the sequence normally appears in non-sequential contexts, making it ideal to test the spatial organization of sequential information that was stored in the long-term memory. This study found a reliable SNARC-like effect for Chinese color words (deciding whether the presented color word was before or after the reference color word “green”), suggesting that, without access to any quantitative information or exposure to any previous training, ordinal representation can still activate a sense of space. The results support that weak ordinal information without quantitative magnitude encoded in the long-term memory can activate spatial representation in a comparison task. PMID:27092100

  8. Spatial Representation of Ordinal Information.

    PubMed

    Zhang, Meng; Gao, Xuefei; Li, Baichen; Yu, Shuyuan; Gong, Tianwei; Jiang, Ting; Hu, Qingfen; Chen, Yinghe

    2016-01-01

    Right hand responds faster than left hand when shown larger numbers and vice-versa when shown smaller numbers (the SNARC effect). Accumulating evidence suggests that the SNARC effect may not be exclusive for numbers and can be extended to other ordinal sequences (e.g., months or letters in the alphabet) as well. In this study, we tested the SNARC effect with a non-numerically ordered sequence: the Chinese notations for the color spectrum (Red, Orange, Yellow, Green, Blue, Indigo, and Violet). Chinese color word sequence reserves relatively weak ordinal information, because each element color in the sequence normally appears in non-sequential contexts, making it ideal to test the spatial organization of sequential information that was stored in the long-term memory. This study found a reliable SNARC-like effect for Chinese color words (deciding whether the presented color word was before or after the reference color word "green"), suggesting that, without access to any quantitative information or exposure to any previous training, ordinal representation can still activate a sense of space. The results support that weak ordinal information without quantitative magnitude encoded in the long-term memory can activate spatial representation in a comparison task. PMID:27092100

  9. Detecting early egocentric and allocentric impairments deficits in Alzheimer’s disease: an experimental study with virtual reality

    PubMed Central

    Serino, Silvia; Morganti, Francesca; Di Stefano, Fabio; Riva, Giuseppe

    2015-01-01

    Several studies have pointed out that egocentric and allocentric spatial impairments are one of the earliest manifestations of Alzheimer’s Disease (AD). It is less clear how a break in the continuous interaction between these two representations may be a crucial marker to detect patients who are at risk to develop dementia. The main objective of this study is to compare the performances of participants suffering from amnestic mild cognitive impairment (aMCI group), patients with AD (AD group) and a control group (CG), using a virtual reality (VR)-based procedure for assessing the abilities in encoding, storing and syncing different spatial representations. In the first task, participants were required to indicate on a real map the position of the object they had memorized, while in the second task they were invited to retrieve its position from an empty version of the same virtual room, starting from a different position. The entire procedure was repeated across three different trials, depending on the object location in the encoding phase. Our finding showed that aMCI patients performed significantly more poorly in the third trial of the first task, showing a deficit in the ability to encode and store an allocentric viewpoint independent representation. On the other hand, AD patients performed significantly more poorly when compared to the CG in the second task, indicating a specific impairment in storing an allocentric viewpoint independent representation and then syncing it with the allocentric viewpoint dependent representation. Furthermore, data suggested that these impairments are not a product of generalized cognitive decline or of general decay in spatial abilities, but instead may reflect a selective deficit in the spatial organization Overall, these findings provide an initial insight into the cognitive underpinnings of amnestic impairment in aMCI and AD patient exploiting the potentiality of VR. PMID:26042034

  10. Allocentric and egocentric reference frames in the processing of three-dimensional haptic space

    PubMed Central

    Kappers, Astrid M. L.

    2008-01-01

    The main goal of our study is to gain insight into the reference frames involved in three-dimensional haptic spatial processing. Previous research has shown that two-dimensional haptic spatial processing is prone to large systematic deviations. A weighted average model that identifies the origin of the systematic error patterns in the biasing influence of an egocentric reference frame on the allocentric reference frame was proposed as an explanation of the results. The basis of the egocentric reference frame was linked either to the hand or to the body. In the present study participants had to construct a field of parallel bars that could be oriented in three dimensions. First, systematic error patterns were found also in this three-dimensional haptic parallelity task. Second, among the different models tested for their accuracy in explaining the error patterns, the Hand-centered weighted average model proved to most closely resemble the data. A participant-specific weighting factor determined the biasing influence of the hand-centered egocentric reference frame. A shift from the allocentric towards the egocentric frame of reference of approximately 20% was observed. These results support the hypothesis that haptic spatial processing is a product of the interplay of diverse, but synergistically operating frames of reference. PMID:18368397

  11. Dorsal striatal dopamine depletion impairs both allocentric and egocentric navigation in rats.

    PubMed

    Braun, Amanda A; Graham, Devon L; Schaefer, Tori L; Vorhees, Charles V; Williams, Michael T

    2012-05-01

    Successful navigation requires interactions among multiple but overlapping neural pathways mediating distinct capabilities, including egocentric (self-oriented, route-based) and allocentric (spatial, map-based) learning. Route-based navigation has been shown to be impaired following acute exposure to the dopaminergic (DA) drugs (+)-methamphetamine and (+)-amphetamine, but not the serotoninergic (5-HT) drugs (±)-3,4-methylenedioxymethamphetamine or (±)-fenfluramine. The dopaminergic-rich neostriatum is involved in both allocentric and egocentric navigation. This experiment tested whether dorsal striatal DA loss using bilateral 6-hydroxydopamine (6-OHDA) injections impaired one or both types of navigation. Two weeks following 6-OHDA injections, rats began testing in the Cincinnati water maze (CWM) followed by the Morris water maze (MWM) for route-based and spatial navigation, respectively. 6-OHDA treatment significantly increased latency and errors in the CWM and path length, latency, and cumulative distance in the MWM with no difference on cued MWM trials. Neostriatal DA levels were reduced by 80% at 2 and 7 weeks post-treatment. In addition, 6-OHDA increased DA turnover and decreased norepinephrine (NE) levels. 6-OHDA injections did not alter monoamine levels in the prefrontal cortex. The data support that neostriatal DA modulates both types of navigation. PMID:22465436

  12. Chronic enhancement of CREB activity in the hippocampus interferes with the retrieval of spatial information

    PubMed Central

    Viosca, Jose; Malleret, Gaël; Bourtchouladze, Rusiko; Benito, Eva; Vronskava, Svetlana; Kandel, Eric R.; Barco, Angel

    2009-01-01

    The activation of cAMP-responsive element-binding protein (CREB)-dependent gene expression is thought to be critical for the formation of different types of long-term memory. To explore the consequences of chronic enhancement of CREB function on spatial memory in mammals, we examined spatial navigation in bitransgenic mice that express in a regulated and restricted manner a constitutively active form of CREB, VP16-CREB, in forebrain neurons. We found that chronic enhancement of CREB activity delayed the acquisition of an allocentric strategy to solve the hidden platform task. The ability to turn on and off transgene expression allowed us to dissect the role of CREB in dissociable memory processes. In mice in which transgene expression was turned on during memory acquisition, turning off the transgene re-established the access to the memory trace, whereas in mice in which transgene expression was turned off during acquisition, turning on the transgene impaired memory expression in a reversible manner, indicating that CREB enhancement specifically interfered with the retrieval of spatial information. The defects on spatial navigation in mice with chronic enhancement of CREB function were not corrected by conditions that increased further CREB-dependent activation of hippocampal memory systems, such as housing in an enriched environment. These results along with previous findings in CREB-deficient mutants indicate that the relationship of CREB-mediated plasticity to spatial memory is an inverted-U function, and that optimal learning in the water maze requires accurate regulation of this pathway. PMID:19237642

  13. Bayesian Integration of Spatial Information

    ERIC Educational Resources Information Center

    Cheng, Ken; Shettleworth, Sara J.; Huttenlocher, Janellen; Rieser, John J.

    2007-01-01

    Spatial judgments and actions are often based on multiple cues. The authors review a multitude of phenomena on the integration of spatial cues in diverse species to consider how nearly optimally animals combine the cues. Under the banner of Bayesian perception, cues are sometimes combined and weighted in a near optimal fashion. In other instances…

  14. Spatial information semantic query based on SPARQL

    NASA Astrophysics Data System (ADS)

    Xiao, Zhifeng; Huang, Lei; Zhai, Xiaofang

    2009-10-01

    How can the efficiency of spatial information inquiries be enhanced in today's fast-growing information age? We are rich in geospatial data but poor in up-to-date geospatial information and knowledge that are ready to be accessed by public users. This paper adopts an approach for querying spatial semantic by building an Web Ontology language(OWL) format ontology and introducing SPARQL Protocol and RDF Query Language(SPARQL) to search spatial semantic relations. It is important to establish spatial semantics that support for effective spatial reasoning for performing semantic query. Compared to earlier keyword-based and information retrieval techniques that rely on syntax, we use semantic approaches in our spatial queries system. Semantic approaches need to be developed by ontology, so we use OWL to describe spatial information extracted by the large-scale map of Wuhan. Spatial information expressed by ontology with formal semantics is available to machines for processing and to people for understanding. The approach is illustrated by introducing a case study for using SPARQL to query geo-spatial ontology instances of Wuhan. The paper shows that making use of SPARQL to search OWL ontology instances can ensure the result's accuracy and applicability. The result also indicates constructing a geo-spatial semantic query system has positive efforts on forming spatial query and retrieval.

  15. Higher or lower? The functional anatomy of perceived allocentric social hierarchies.

    PubMed

    Farrow, Tom F D; Jones, Sarah C; Kaylor-Hughes, Catherine J; Wilkinson, Iain D; Woodruff, Peter W R; Hunter, Michael D; Spence, Sean A

    2011-08-15

    The perception and judgement of social hierarchies forms an integral part of social cognition. Hierarchical judgements can be either self-referential or allocentric (pertaining to two or more external agents). In psychiatric conditions such as dissocial personality disorder and schizophrenia, the impact of hierarchies may be problematic. We sought to elucidate the brain regions involved in judging allocentric social hierarchies. Twenty-two healthy male subjects underwent three fMRI scans. During scanning, subjects answered questions concerning visually-presented target pairs of human individual's relative superiority within a specific social hierarchy or their perceived degree of social alliance (i.e., whether they were "friends or enemies"). Subjects also made judgements relating to target pairs' age, gender and fame to control for confounding factors and performed a baseline numerical task. Response times increased in line with hypothesized ascending executive load. Both social hierarchy and social alliance judgements activated left ventrolateral prefrontal cortex (VLPFC), left dorsal inferior frontal gyrus (IFG) and bilateral fusiform gyri. In addition, social alliance judgements activated right dorsal IFG and medial prefrontal cortex. When compared directly with social alliance, social hierarchy judgements activated left orbitofrontal cortex. Detecting the presence of social hierarchies and judging other's relative standing within them implicates the cognitive executive, in particular the VLPFC. Our finding informs accounts of 'normal' social cognition but our method also provides a means of probing the dissocial brain in personality disorder and schizophrenia where executive function may be dysfunctional. PMID:21664277

  16. Egocentric and allocentric reference frames for catching a falling object.

    PubMed

    Le Séac'h, Anne Brec'hed; Senot, Patrice; McIntyre, Joseph

    2010-04-01

    When programming movement, one must account for gravitational acceleration. This is particularly important when catching a falling object because the task requires a precise estimate of time-to-contact. Knowledge of gravity's effects is intimately linked to our definition of 'up' and 'down'. Both directions can be described in an allocentric reference frame, based on visual and/or gravitational cues, or in an egocentric reference frame in which the body axis is taken as vertical. To test which frame humans use to predict gravity's effect, we asked participants to intercept virtual balls approaching from above or below with artificially controlled acceleration that could be congruent or not with gravity. To dissociate between these frames, subjects were seated upright (trunk parallel to gravity) or lying down (body axis orthogonal to the gravitational axis). We report data in line with the use of an allocentric reference frame and discuss its relevance depending on available gravity-related cues. PMID:20024651

  17. Gender comparisons in the private, collective, and allocentric selves.

    PubMed

    Madson, L; Trafimow, D

    2001-08-01

    Researchers (e.g., M. B. Brewer & W. Gardner, 1996; H. C. Triandis, D. K. S. Chan, D. P. S. Bhawuk, S. Iwao, & J. P. B. Sinha, 1995) have suggested expansion of the standard model of individualism-collectivism to include people's close personal relationships in addition to their identification with in-groups. There has been considerable discussion of the hypothesis that women are more collective, interdependent, relational, and allocentric than men (e.g., S. E. Cross & L. Madson, 1997; Y. Kashima et al., 1995). In the present study, the authors used the Twenty Statements Test (M. H. Kuhn & T. McPartland, 1954) to examine gender differences in the self-concept by assessing the accessibility of private, collective, and allocentric self-cognitions. The U.S. women described themselves with more allocentric and more collective self-cognitions than did the U.S. men. Discussion focuses on the implications of those data for interpretation of other gender differences as well as for traditional models of individualism-collectivism. PMID:11577852

  18. Allocentric coding in ventral and dorsal routes during real-time reaching: Evidence from imaging-guided multi-site brain stimulation.

    PubMed

    Adam, J J; Bovend'Eerdt, T J H; Schuhmann, Teresa; Sack, A T

    2016-03-01

    Recent evidence has revealed an advantage for movements to last target positions in a structured visual display, suggesting a mediating role of allocentric, in addition to egocentric, information in goal-directed reaching. This notion is accommodated by the recently updated perception-action model (Milner and Goodale, 2008), which postulates functional roles of ventral and dorsal neural areas in allocentric coding. In the present study, we used imaging-guided multi-site continuous theta burst stimulation (cTBS) over regions of the ventral and dorsal processing streams to unravel their functional contribution on visually guided reaching in two display conditions: the "egocentric" condition where the target appeared in an empty display and the "allocentric" condition where the target appeared in a structured display with placeholders marking possible target locations. Cortical sites for cTBS were identified individually for each participant via coregistration with magnetic resonance scans. Results indicated that cTBS in the egocentric condition did not affect movement time, but cTBS in the allocentric condition modulated movement time contingent on stimulation site and target position. In particular, cTBS over the lateral occipital cortex (part of the ventral stream) and over the angular gyrus (part of the dorsal stream) eliminated the last-target advantage by slowing down reaching to the salient last target position. cTBS over the superior parietal occipital cortex did not affect the last-target advantage. These outcomes provide the first causal evidence for allocentric coding in ventral and dorsal routes during real-time reaching, thereby supporting the updated perception-action model. PMID:26698396

  19. Allocentric Coding of Object-to-Object Relations in Overlearned and Novel Environments

    ERIC Educational Resources Information Center

    Holmes, Melinda C.; Sholl, M. Jeanne

    2005-01-01

    R. F. Wang and E. S. Spelke's (2000) finding that disorientation disrupts knowledge is consistent with egocentric but not allocentric coding of object location. The present experiments tested the hypothesis that egocentric coding may dominate early on but that once an allocentric representation is established, then target location is retrieved…

  20. The oblique effect is both allocentric and egocentric

    PubMed Central

    Mikellidou, Kyriaki; Cicchini, Guido Marco; Thompson, Peter G.; Burr, David C.

    2016-01-01

    Despite continuous movements of the head, humans maintain a stable representation of the visual world, which seems to remain always upright. The mechanisms behind this stability are largely unknown. To gain some insight on how head tilt affects visual perception, we investigate whether a well-known orientation-dependent visual phenomenon, the oblique effect—superior performance for stimuli at cardinal orientations (0° and 90°) compared with oblique orientations (45°)—is anchored in egocentric or allocentric coordinates. To this aim, we measured orientation discrimination thresholds at various orientations for different head positions both in body upright and in supine positions. We report that, in the body upright position, the oblique effect remains anchored in allocentric coordinates irrespective of head position. When lying supine, gravitational effects in the plane orthogonal to gravity are discounted. Under these conditions, the oblique effect was less marked than when upright, and anchored in egocentric coordinates. The results are well explained by a simple “compulsory fusion” model in which the head-based and the gravity-based signals are combined with different weightings (30% and 70%, respectively), even when this leads to reduced sensitivity in orientation discrimination. PMID:26129862

  1. Memory Effects in Visual Spatial Information Processing.

    ERIC Educational Resources Information Center

    Fishbein, Harold D.

    1978-01-01

    Eight, ten, and twelve year old children were tested on a novel procedure involving the successive presentation of standard and comparision stimuli. Two hypotheses were evaluated: one dealing with memory effects, and the other with children's pretesting of choice responses in spatial information processing. (Editor/RK)

  2. Ontogeny of neural circuits underlying spatial memory in the rat

    PubMed Central

    Ainge, James A.; Langston, Rosamund F.

    2012-01-01

    Spatial memory is a well-characterized psychological function in both humans and rodents. The combined computations of a network of systems including place cells in the hippocampus, grid cells in the medial entorhinal cortex and head direction cells found in numerous structures in the brain have been suggested to form the neural instantiation of the cognitive map as first described by Tolman in 1948. However, while our understanding of the neural mechanisms underlying spatial representations in adults is relatively sophisticated, we know substantially less about how this network develops in young animals. In this article we briefly review studies examining the developmental timescale that these systems follow. Electrophysiological recordings from very young rats show that directional information is at adult levels at the outset of navigational experience. The systems supporting allocentric memory, however, take longer to mature. This is consistent with behavioral studies of young rats which show that spatial memory based on head direction develops very early but that allocentric spatial memory takes longer to mature. We go on to report new data demonstrating that memory for associations between objects and their spatial locations is slower to develop than memory for objects alone. This is again consistent with previous reports suggesting that adult like spatial representations have a protracted development in rats and also suggests that the systems involved in processing non-spatial stimuli come online earlier. PMID:22403529

  3. Spatial Paradigm for Information Retrieval and Exploration

    1996-10-10

    The SPIRE system consists of software for visual analysis of primarily text based information sources. This technology enables the content analysis of text documents without reading all the documents. It employs several algorithms for text and word proximity analysis. It identifies the key themes within the text documents. From this analysis, it projects the results onto a visual spatial proximity display (Galaxies or Themescape) where items (documents and/or themes) visually close to each other aremore » known to have content which is close to each other. Innovative interaction techniques then allow for dynamic visual analysis of large text based information spaces.« less

  4. What does spatial alternation tell us about retrosplenial cortex function?

    PubMed Central

    Nelson, Andrew J. D.; Powell, Anna L.; Holmes, Joshua D.; Vann, Seralynne D.; Aggleton, John P.

    2015-01-01

    The retrosplenial cortex supports navigation, but there are good reasons to suppose that the retrosplenial cortex has a very different role in spatial memory from that of the hippocampus and anterior thalamic nuclei. For example, retrosplenial lesions appear to have little or no effect on standard tests of spatial alternation. To examine these differences, the current study sought to determine whether the retrosplenial cortex is important for just one spatial cue type (e.g., allocentric, directional or intra-maze cues) or whether the retrosplenial cortex helps the animal switch between competing spatial strategies or competing cue types. Using T-maze alternation, retrosplenial lesion rats were challenged with situations in which the available spatial information between the sample and test phases was changed, so taxing the interaction between different cue types. Clear lesion deficits emerged when intra- and extra-maze cues were placed in conflict (by rotating the maze between the sample and choice phases), or when the animals were tested in the dark in a double-maze. Finally, temporary inactivation of the retrosplenial cortex by muscimol infusions resulted in a striking deficit on standard T-maze alternation, indicating that, over time, other sites may be able to compensate for the loss of the retrosplenial cortex. This pattern of results is consistent with the impoverished use of both allocentric and directional information, exacerbated by an impaired ability to switch between different cue types. PMID:26042009

  5. Spatial information enhanced by non-spatial information in hippocampal granule cells.

    PubMed

    Hayakawa, Hirofumi; Samura, Toshikazu; Kamijo, Tadanobu Chuyo; Sakai, Yutaka; Aihara, Takeshi

    2015-02-01

    The hippocampus organizes sequential memory composed of non-spatial information (such as objects and odors) and spatial information (places). The dentate gyrus (DG) in the hippocampus receives two types of information from the lateral and medial entorhinal cortices. Non-spatial and spatial information is delivered respectively to distal and medial dendrites (MDs) of granule cells (GCs) within the molecular layer in the DG. To investigate the role of the association of those two inputs, we measured the response characteristics of distal and MDs of a GC in a rat hippocampal slice and developed a multi-compartment GC model with dynamic synapses; this model reproduces the response characteristics of the dendrites. Upon applying random inputs or input sequences generated by a Markov process to the computational model, it was found that a high-frequency random pulse input to distal dendrites (DDs) and, separately, regular burst inputs to MDs were effective for inducing GC activation. Furthermore, when the random and theta burst inputs were simultaneously applied to the respective dendrites, the pattern discrimination for theta burst input to MDs that caused slight GC activation was enhanced in the presence of random input to DDs. These results suggest that the temporal pattern discrimination of spatial information is originally involved in a synaptic characteristic in GCs and is enhanced by non-spatial information input to DDs. Consequently, the co-activation of two separate inputs may play a crucial role in the information processing on dendrites of GCs by usefully combing each temporal sequence. PMID:26052358

  6. Sensory Substitution: The Spatial Updating of Auditory Scenes “Mimics” the Spatial Updating of Visual Scenes

    PubMed Central

    Pasqualotto, Achille; Esenkaya, Tayfun

    2016-01-01

    Visual-to-auditory sensory substitution is used to convey visual information through audition, and it was initially created to compensate for blindness; it consists of software converting the visual images captured by a video-camera into the equivalent auditory images, or “soundscapes”. Here, it was used by blindfolded sighted participants to learn the spatial position of simple shapes depicted in images arranged on the floor. Very few studies have used sensory substitution to investigate spatial representation, while it has been widely used to investigate object recognition. Additionally, with sensory substitution we could study the performance of participants actively exploring the environment through audition, rather than passively localizing sound sources. Blindfolded participants egocentrically learnt the position of six images by using sensory substitution and then a judgment of relative direction task (JRD) was used to determine how this scene was represented. This task consists of imagining being in a given location, oriented in a given direction, and pointing towards the required image. Before performing the JRD task, participants explored a map that provided allocentric information about the scene. Although spatial exploration was egocentric, surprisingly we found that performance in the JRD task was better for allocentric perspectives. This suggests that the egocentric representation of the scene was updated. This result is in line with previous studies using visual and somatosensory scenes, thus supporting the notion that different sensory modalities produce equivalent spatial representation(s). Moreover, our results have practical implications to improve training methods with sensory substitution devices (SSD). PMID:27148000

  7. A Spatial Classifier for Multispectral Data Using Contextual Information

    NASA Technical Reports Server (NTRS)

    Hung, Chih-Cheng; Fahsi, Ahmed; Coleman, Tommy

    1998-01-01

    Connectivity describes the spatial relationship among pixels. A spatial classifier which employs the sigma probability concept of the Gaussian distribution and a type of contextual information connectivity of the pixels, is studied in this paper. This spatial classifier attempts to replicate the kind of spatial synthesis done by the human analyst during visual interpretation or to capture the spatial relationships inherent in an aerial photograph. Several classification results of the Landsat TM data using this classifier with different window sizes for capturing the contextual information are illustrated and compared.

  8. The Forced Choice Dilemma: A Model Incorporating Idiocentric/Allocentric Cultural Orientation

    ERIC Educational Resources Information Center

    Jung, Jae Yup; McCormick, John; Gross, Miraca U. M.

    2012-01-01

    This study developed and tested a new model of the forced choice dilemma (i.e., the belief held by some intellectually gifted students that they must choose between academic achievement and peer acceptance) that incorporates individual-level cultural orientation variables (i.e., vertical allocentrism and vertical idiocentrism). A survey that had…

  9. Cues, context, and long-term memory: the role of the retrosplenial cortex in spatial cognition

    PubMed Central

    Miller, Adam M. P.; Vedder, Lindsey C.; Law, L. Matthew; Smith, David M.

    2014-01-01

    Spatial navigation requires memory representations of landmarks and other navigation cues. The retrosplenial cortex (RSC) is anatomically positioned between limbic areas important for memory formation, such as the hippocampus (HPC) and the anterior thalamus, and cortical regions along the dorsal stream known to contribute importantly to long-term spatial representation, such as the posterior parietal cortex. Damage to the RSC severely impairs allocentric representations of the environment, including the ability to derive navigational information from landmarks. The specific deficits seen in tests of human and rodent navigation suggest that the RSC supports allocentric representation by processing the stable features of the environment and the spatial relationships among them. In addition to spatial cognition, the RSC plays a key role in contextual and episodic memory. The RSC also contributes importantly to the acquisition and consolidation of long-term spatial and contextual memory through its interactions with the HPC. Within this framework, the RSC plays a dual role as part of the feedforward network providing sensory and mnemonic input to the HPC and as a target of the hippocampal-dependent systems consolidation of long-term memory. PMID:25140141

  10. Spatial information transmission using axial temporal coherence coding.

    PubMed

    Micó, Vicente; García, Javier; Ferreira, Carlos; Sylman, David; Zalevsky, Zeev

    2007-04-01

    We present an approach that can be used for transmission of information through space-limited systems or for superresolution. The spatial information is coded with different axial temporal coherence by interfering every spatial region in the input with the same region, but with a certain known delay in the longitudinal axis. Every spatial region has different delay. After mixing all of the spatial information, it is transmitted through the space-limited system. At the detection the information is passed through a similar interference setup containing certain axial delay. By temporally scanning along the longitudinal axis, each time a different spatial region that was coded with the corresponding axial delay is reconstructed. To allow coding of different spatial regions with different and small axial delays, we use a thermal light source that has very short coherence length. We include experimental validation of the presented approach. PMID:17339919

  11. The display of spatial information and visually guided behavior

    NASA Technical Reports Server (NTRS)

    Bennett, C. Thomas

    1991-01-01

    The basic informational elements of spatial orientation are attitude and position within a coordinate system. The problem that faces aeronautical designers is that a pilot must deal with several coordinate systems, sometimes simultaneously. The display must depict unambiguously not only position and attitude, but also designate the relevant coordinate system. If this is not done accurately, spatial disorientation can occur. The different coordinate systems used in aeronautical tasks and the problems that occur in the display of spatial information are explained.

  12. Gesture is more effective than spatial language in encoding spatial information.

    PubMed

    So, Wing-Chee; Shum, Priscilla Lok-Chee; Wong, Miranda Kit-Yi

    2015-01-01

    The present research investigates whether producing gestures with and without speech facilitates route learning at different levels of route complexity and in learners with different levels of spatial skills. It also examines whether the facilitation effect of gesture is stronger than that of spatial language. Adults studied routes with 10, 13, and 16 steps and reconstructed them with sticks, either without rehearsal or after rehearsal by producing gestures with speech, gestures alone, or speech only. For all levels of route complexity and spatial skills, participants who were encouraged to gesture (with or without speech) during rehearsal had the best recall. Additionally, we found that number of steps rehearsed in gesture, but not that rehearsed in speech, predicted the recall accuracy. Thus, gesture is more effective than spatial language in encoding spatial information, and thereby enhancing spatial recall. These results further corroborate the beneficial nature of gesture in processing spatial information. PMID:25671654

  13. APPLICATION OF SPATIAL INFORMATION TECHNOLOGY TO PETROLEUM RESOURCE ASSESSMENT ANALYSIS.

    USGS Publications Warehouse

    Miller, Betty M.; Domaratz, Michael A.

    1984-01-01

    Petroleum resource assessment procedures require the analysis of a large volume of spatial data. The US Geological Survey (USGS) has developed and applied spatial information handling procedures and digital cartographic techniques to a recent study involving the assessment of oil and gas resource potential for 74 million acres of designated and proposed wilderness lands in the western United States. The part of the study which dealt with the application of spatial information technology to petroleum resource assessment procedures is reviewed. A method was designed to expedite the gathering, integrating, managing, manipulating and plotting of spatial data from multiple data sources that are essential in modern resource assessment procedures.

  14. Spatial Mutual Information Based Hyperspectral Band Selection for Classification

    PubMed Central

    2015-01-01

    The amount of information involved in hyperspectral imaging is large. Hyperspectral band selection is a popular method for reducing dimensionality. Several information based measures such as mutual information have been proposed to reduce information redundancy among spectral bands. Unfortunately, mutual information does not take into account the spatial dependency between adjacent pixels in images thus reducing its robustness as a similarity measure. In this paper, we propose a new band selection method based on spatial mutual information. As validation criteria, a supervised classification method using support vector machine (SVM) is used. Experimental results of the classification of hyperspectral datasets show that the proposed method can achieve more accurate results. PMID:25918742

  15. Indoor Spatial Updating with Reduced Visual Information

    PubMed Central

    Legge, Gordon E.; Gage, Rachel; Baek, Yihwa; Bochsler, Tiana M.

    2016-01-01

    Purpose Spatial updating refers to the ability to keep track of position and orientation while moving through an environment. People with impaired vision may be less accurate in spatial updating with adverse consequences for indoor navigation. In this study, we asked how artificial restrictions on visual acuity and field size affect spatial updating, and also judgments of the size of rooms. Methods Normally sighted young adults were tested with artificial restriction of acuity in Mild Blur (Snellen 20/135) and Severe Blur (Snellen 20/900) conditions, and a Narrow Field (8°) condition. The subjects estimated the dimensions of seven rectangular rooms with and without these visual restrictions. They were also guided along three-segment paths in the rooms. At the end of each path, they were asked to estimate the distance and direction to the starting location. In Experiment 1, the subjects walked along the path. In Experiment 2, they were pushed in a wheelchair to determine if reduced proprioceptive input would result in poorer spatial updating. Results With unrestricted vision, mean Weber fractions for room-size estimates were near 20%. Severe Blur but not Mild Blur yielded larger errors in room-size judgments. The Narrow Field was associated with increased error, but less than with Severe Blur. There was no effect of visual restriction on estimates of distance back to the starting location, and only Severe Blur yielded larger errors in the direction estimates. Contrary to expectation, the wheelchair subjects did not exhibit poorer updating performance than the walking subjects, nor did they show greater dependence on visual condition. Discussion If our results generalize to people with low vision, severe deficits in acuity or field will adversely affect the ability to judge the size of indoor spaces, but updating of position and orientation may be less affected by visual impairment. PMID:26943674

  16. Toward Semantic Web Infrastructure for Spatial FEATURES' Information

    NASA Astrophysics Data System (ADS)

    Arabsheibani, R.; Ariannamazi, S.; Hakimpour, F.

    2015-12-01

    The Web and its capabilities can be employed as a tool for data and information integration if comprehensive datasets and appropriate technologies and standards enable the web with interpretation and easy alignment of data and information. Semantic Web along with the spatial functionalities enable the web to deal with the huge amount of data and information. The present study investigate the advantages and limitations of the Spatial Semantic Web and compare its capabilities with relational models in order to build a spatial data infrastructure. An architecture is proposed and a set of criteria is defined for the efficiency evaluation. The result demonstrate that when using the data with special characteristics such as schema dynamicity, sparse data or available relations between the features, the spatial semantic web and graph databases with spatial operations are preferable.

  17. The value of spatial information in MPA network design

    PubMed Central

    Costello, Christopher; Rassweiler, Andrew; Siegel, David; De Leo, Giulio; Micheli, Fiorenza; Rosenberg, Andrew

    2010-01-01

    The science of spatial fisheries management, which combines ecology, oceanography, and economics, has matured significantly. As a result, there have been recent advances in exploiting spatially explicit data to develop spatially explicit management policies, such as networks of marine protected areas (MPAs). However, when data are sparse, spatially explicit policies become less viable, and we must instead rely on blunt policies such as total allowable catches or imprecisely configured networks of MPAs. Therefore, spatial information has the potential to change management approaches and thus has value. We develop a general framework within which to analyze the value of information for spatial fisheries management and apply that framework to several US Pacific coast fisheries. We find that improved spatial information can increase fishery value significantly (>10% in our simulations), and that it changes dramatically the efficient management approach—switching from diffuse effort everywhere to a strategy where fishing is spatially targeted, with some areas under intensive harvest and others closed to fishing. Using all available information, even when incomplete, is essential to management success and may as much as double fishery value relative to using (admittedly incorrect) assumptions commonly invoked. PMID:20176962

  18. The Role of Spatial Information Systems in Environmental Emergency Management.

    ERIC Educational Resources Information Center

    Mondschein, Lawrence G.

    1994-01-01

    Reviews the use of spatial data and information technology by environmental managers and emergency responders. Discussion includes environmental legislation, the Toxic Chemical Release Inventory (TRI) database, public access to environmental information, information standardization problems, emergency response software development and a case study…

  19. Assessing Spatial Learning and Memory in Rodents

    PubMed Central

    Vorhees, Charles V.; Williams, Michael T.

    2014-01-01

    Maneuvering safely through the environment is central to survival of almost all species. The ability to do this depends on learning and remembering locations. This capacity is encoded in the brain by two systems: one using cues outside the organism (distal cues), allocentric navigation, and one using self-movement, internal cues and nearby proximal cues, egocentric navigation. Allocentric navigation involves the hippocampus, entorhinal cortex, and surrounding structures; in humans this system encodes allocentric, semantic, and episodic memory. This form of memory is assessed in laboratory animals in many ways, but the dominant form of assessment is the Morris water maze (MWM). Egocentric navigation involves the dorsal striatum and connected structures; in humans this system encodes routes and integrated paths and, when overlearned, becomes procedural memory. In this article, several allocentric assessment methods for rodents are reviewed and compared with the MWM. MWM advantages (little training required, no food deprivation, ease of testing, rapid and reliable learning, insensitivity to differences in body weight and appetite, absence of nonperformers, control methods for proximal cue learning, and performance effects) and disadvantages (concern about stress, perhaps not as sensitive for working memory) are discussed. Evidence-based design improvements and testing methods are reviewed for both rats and mice. Experimental factors that apply generally to spatial navigation and to MWM specifically are considered. It is concluded that, on balance, the MWM has more advantages than disadvantages and compares favorably with other allocentric navigation tasks. PMID:25225309

  20. Extracting spatial information from large aperture exposures of diffuse sources

    NASA Technical Reports Server (NTRS)

    Clarke, J. T.; Moos, H. W.

    1981-01-01

    The spatial properties of large aperture exposures of diffuse emission can be used both to investigate spatial variations in the emission and to filter out camera noise in exposures of weak emission sources. Spatial imaging can be accomplished both parallel and perpendicular to dispersion with a resolution of 5-6 arc sec, and a narrow median filter running perpendicular to dispersion across a diffuse image selectively filters out point source features, such as reseaux marks and fast particle hits. Spatial information derived from observations of solar system objects is presented.

  1. [Construction of traditional Chinese medicine resources information spatial database].

    PubMed

    Zhao, Yu-yang; Sun, Cheng-zhong; Yang, Ze-dong

    2015-03-01

    The informatization of traditional Chinese medicine resources is the basis of modern medicine. With a spatial attribute traditional Chinese medicine resources could be carried out for in-depth spatial analysis, data mining and traditional Chinese medicine resources regional industrial layout. In this paper, we took the data of Glycyrrhiza uralensis in the third national Chinese medicine resources survey as the experimental data, described the principles and structure of traditional Chinese medicine resources spatial information database. We also described the establishment of analysis model with the help of this spatial database. PMID:26226774

  2. Semantic overlay network for large-scale spatial information indexing

    NASA Astrophysics Data System (ADS)

    Zou, Zhiqiang; Wang, Yue; Cao, Kai; Qu, Tianshan; Wang, Zhongmin

    2013-08-01

    The increased demand for online services of spatial information poses new challenges to the combined filed of Computer Science and Geographic Information Science. Amongst others, these include fast indexing of spatial data in distributed networks. In this paper we propose a novel semantic overlay network for large-scale multi-dimensional spatial information indexing, called SON_LSII, which has a hybrid structure integrating a semantic quad-tree and Chord ring. The SON_LSII is a small world overlay network that achieves a very competitive trade-off between indexing efficiency and maintenance overhead. To create SON_LSII, we use an effective semantic clustering strategy that considers two aspects, i.e., the semantic of spatial information that peer holds in overlay network and physical network performances. Based on SON_LSII, a mapping method is used to reduce the multi-dimensional features into a single dimension and an efficient indexing algorithm is presented to support complex range queries of the spatial information with a massive number of concurrent users. The results from extensive experiments demonstrate that SON_LSII is superior to existing overlay networks in various respects, including scalability, maintenance, rate of indexing hits, indexing logical hops, and adaptability. Thus, the proposed SON_LSII can be used for large-scale spatial information indexing.

  3. Effective spatial database support for acquiring spatial information from remote sensing images

    NASA Astrophysics Data System (ADS)

    Jin, Peiquan; Wan, Shouhong; Yue, Lihua

    2009-12-01

    In this paper, a new approach to maintain spatial information acquiring from remote-sensing images is presented, which is based on Object-Relational DBMS. According to this approach, the detected and recognized results of targets are stored and able to be further accessed in an ORDBMS-based spatial database system, and users can access the spatial information using the standard SQL interface. This approach is different from the traditional ArcSDE-based method, because the spatial information management module is totally integrated into the DBMS and becomes one of the core modules in the DBMS. We focus on three issues, namely the general framework for the ORDBMS-based spatial database system, the definitions of the add-in spatial data types and operators, and the process to develop a spatial Datablade on Informix. The results show that the ORDBMS-based spatial database support for image-based target detecting and recognition is easy and practical to be implemented.

  4. Effects of Spatial Aggregation of Soil Spatial Information on Watershed Hydrological Modeling

    NASA Astrophysics Data System (ADS)

    Li, R.; Zhu, A.; Song, X.

    2011-12-01

    Impacts of detailed soil spatial information on hydrological modeling across different spatial scales are lack of comprehensive understanding. This paper examines such effects by comparing the simulated runoffs across scales from watershed models based on two different levels of soil spatial information, 10 meter resolution soil data derived from SoLIM and the 1:24 000 scale Soil Survey Geographic (SSURGO) data base. The examination was conducted at three different spatial scales: two at different watershed size levels and one at the model minimum simulation unit level. A fully distributed hydrologic model and a semi-distributed model were used to assess the effects. The study was conducted in a 19.5 square kilometers watershed located in northwest Dane county, Wisconsin. The results showed that differences in simulated runoff at the minimum simulation unit level are large. However, the difference gradually decreases as the spatial scale of simulation units increases. For sub-basins larger than 10 square kilometers in Brewery Creek, simulated stream flows using spatially detailed soil data, SoLIM data, would not vary significantly from those using SSURGO soil data. The unique findings of this study provide an important and unified perspective on the different views reported in the literature concerning how spatial detail of the input soil data affects watershed modeling and offer a potential useful basis for selecting the level of detail of soil spatial information appropriate for watershed modeling at a given model simulation scale.

  5. The impact of egocentric vs. allocentric agency attributions on the neural bases of reasoning about social rules.

    PubMed

    Canessa, Nicola; Pantaleo, Giuseppe; Crespi, Chiara; Gorini, Alessandra; Cappa, Stefano F

    2014-09-18

    We used the "standard" and "switched" social contract versions of the Wason Selection-task to investigate the neural bases of human reasoning about social rules. Both these versions typically elicit the deontically correct answer, i.e. the proper identification of the violations of a conditional obligation. Only in the standard version of the task, however, this response corresponds to the logically correct one. We took advantage of this differential adherence to logical vs. deontical accuracy to test the different predictions of logic rule-based vs. visuospatial accounts of inferential abilities in 14 participants who solved the standard and switched versions of the Selection-task during functional-Magnetic-Resonance-Imaging. Both versions activated the well known left fronto-parietal network of deductive reasoning. The standard version additionally recruited the medial parietal and right inferior parietal cortex, previously associated with mental imagery and with the adoption of egocentric vs. allocentric spatial reference frames. These results suggest that visuospatial processes encoding one's own subjective experience in social interactions may support and shape the interpretation of deductive arguments and/or the resulting inferences, thus contributing to elicit content effects in human reasoning. PMID:24928617

  6. Incorporating spatial information into gas plume detection in hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Grant, Cameron S.

    Detection of chemical plumes in hyperpsectral data is a problem having solutions that focus on spectral information. These solutions neglect the presence of the spatial information in the scene. The spatial information is exploited in this work by assignment of prior probabilities to neighborhood configurations of signal presence or absence. These probabilities are leveraged in a total probability approach to testing for signal presence in a pixel of interest. The two new algorithms developed are named spatial information detection enhancement (SIDE) and bolt--on SIDE (B--SIDE). The results are explored in comparison to the clutter matched filter (CMF), a standard spectral technique, and to several supervised machine learning techniques. The results show a great improvement of SIDE over these other techniques, in some cases showing the poorest performance of the SIDE filter being much better than the CMF at its best.

  7. The agent-based spatial information semantic grid

    NASA Astrophysics Data System (ADS)

    Cui, Wei; Zhu, YaQiong; Zhou, Yong; Li, Deren

    2006-10-01

    Analyzing the characteristic of multi-Agent and geographic Ontology, The concept of the Agent-based Spatial Information Semantic Grid (ASISG) is defined and the architecture of the ASISG is advanced. ASISG is composed with Multi-Agents and geographic Ontology. The Multi-Agent Systems are composed with User Agents, General Ontology Agent, Geo-Agents, Broker Agents, Resource Agents, Spatial Data Analysis Agents, Spatial Data Access Agents, Task Execution Agent and Monitor Agent. The architecture of ASISG have three layers, they are the fabric layer, the grid management layer and the application layer. The fabric layer what is composed with Data Access Agent, Resource Agent and Geo-Agent encapsulates the data of spatial information system so that exhibits a conceptual interface for the Grid management layer. The Grid management layer, which is composed with General Ontology Agent, Task Execution Agent and Monitor Agent and Data Analysis Agent, used a hybrid method to manage all resources that were registered in a General Ontology Agent that is described by a General Ontology System. The hybrid method is assembled by resource dissemination and resource discovery. The resource dissemination push resource from Local Ontology Agent to General Ontology Agent and the resource discovery pull resource from the General Ontology Agent to Local Ontology Agents. The Local Ontology Agent is derived from special domain and describes the semantic information of local GIS. The nature of the Local Ontology Agents can be filtrated to construct a virtual organization what could provides a global scheme. The virtual organization lightens the burdens of guests because they need not search information site by site manually. The application layer what is composed with User Agent, Geo-Agent and Task Execution Agent can apply a corresponding interface to a domain user. The functions that ASISG should provide are: 1) It integrates different spatial information systems on the semantic The Grid

  8. Spatial information outflow from the hippocampal circuit: distributed spatial coding and phase precession in the subiculum

    PubMed Central

    Kim, Steve M.; Ganguli, Surya; Frank, Loren M.

    2012-01-01

    Hippocampal place cells convey spatial information through a combination of spatially-selective firing and theta phase precession. The way in which this information influences regions like the subiculum that receive input from the hippocampus remains unclear. The subiculum receives direct inputs from area CA1 of the hippocampus and sends divergent output projections to many other parts of the brain, so we examined the firing patterns of rat subicular neurons. We found a substantial transformation in the subicular code for space from sparse to dense firing rate representations along a proximal-distal anatomical gradient: neurons in the proximal subiculum are more similar to canonical, sparsely firing hippocampal place cells, whereas neurons in the distal subiculum have higher firing rates and more distributed spatial firing patterns. Using information theory, we found that the more distributed spatial representation in the subiculum carries, on average, more information about spatial location and context than the sparse spatial representation in CA1. Remarkably, despite the disparate firing rate properties of subicular neurons, we found that neurons at all proximal-distal locations exhibit robust theta phase precession, with similar spiking oscillation frequencies as neurons in area CA1. Our findings suggest that the subiculum is specialized to compress sparse hippocampal spatial codes into highly informative distributed codes suitable for efficient communication to other brain regions. Moreover, despite this substantial compression, the subiculum maintains finer scale temporal properties that may allow it to participate in oscillatory phase coding and spike timing-dependent plasticity in coordination with other regions of the hippocampal circuit. PMID:22915100

  9. Optimizing information flow in small genetic networks. IV. Spatial coupling

    NASA Astrophysics Data System (ADS)

    Sokolowski, Thomas R.; Tkačik, Gašper

    2015-06-01

    We typically think of cells as responding to external signals independently by regulating their gene expression levels, yet they often locally exchange information and coordinate. Can such spatial coupling be of benefit for conveying signals subject to gene regulatory noise? Here we extend our information-theoretic framework for gene regulation to spatially extended systems. As an example, we consider a lattice of nuclei responding to a concentration field of a transcriptional regulator (the input) by expressing a single diffusible target gene. When input concentrations are low, diffusive coupling markedly improves information transmission; optimal gene activation functions also systematically change. A qualitatively different regulatory strategy emerges where individual cells respond to the input in a nearly steplike fashion that is subsequently averaged out by strong diffusion. While motivated by early patterning events in the Drosophila embryo, our framework is generically applicable to spatially coupled stochastic gene expression models.

  10. Optimizing information flow in small genetic networks. IV. Spatial coupling.

    PubMed

    Sokolowski, Thomas R; Tkačik, Gašper

    2015-06-01

    We typically think of cells as responding to external signals independently by regulating their gene expression levels, yet they often locally exchange information and coordinate. Can such spatial coupling be of benefit for conveying signals subject to gene regulatory noise? Here we extend our information-theoretic framework for gene regulation to spatially extended systems. As an example, we consider a lattice of nuclei responding to a concentration field of a transcriptional regulator (the input) by expressing a single diffusible target gene. When input concentrations are low, diffusive coupling markedly improves information transmission; optimal gene activation functions also systematically change. A qualitatively different regulatory strategy emerges where individual cells respond to the input in a nearly steplike fashion that is subsequently averaged out by strong diffusion. While motivated by early patterning events in the Drosophila embryo, our framework is generically applicable to spatially coupled stochastic gene expression models. PMID:26172739

  11. Embodied representation of the body contains veridical spatial information.

    PubMed

    Struiksma, Marijn E; Noordzij, Matthijs L; Postma, Albert

    2011-06-01

    In two experiments, the extent to which mental body representations contain spatial information was examined. Participants were asked to compare distances between various body parts. Similar to what happens when people compare distances on a real visual stimulus, they were faster as the distance differences between body parts became larger (Experiment 1), and this effect could not (only) be explained by the crossing of major bodily categories (umbilicus to knee vs. knee to ankle; Experiment 2). In addition, participants also performed simple animate/inanimate verification on a set of nouns. The nouns describing animate items were names of body parts. A spatial priming effect was found: Verification was faster for body part items preceded by body parts in close spatial proximity. This suggests automatic activation of spatial body information. Taken together, results from the distance comparison task and the property verification task showed that mental body representations contain both categorical and more metric spatial information. These findings are further discussed in terms of recent embodied cognition theories. PMID:21424986

  12. Leadership, OCB and Individual Differences: Idiocentrism and Allocentrism as Moderators of the Relationship between Transformational and Transactional Leadership and OCB

    PubMed Central

    Nahum-Shani, Inbal; Somech, Anit

    2015-01-01

    We propose and test a framework which suggests that the relationships between leadership styles and Organizational Citizenship Behaviors (OCB) are contingent upon employee cultural-based individual differences. More specifically, we examine whether followers' idiocentrism and allocentrism moderate the relationship between transformational and transactional leadership and followers' OCB. Survey data, collected from a sample of school teachers and their principals from the Israeli kibbutzim and urban sectors, support our hypotheses. We found the relationship between transformational leadership and OCB to be positive to the extent that allocentrism increases, and negative to the extent that idiocentrism increases. We also found the relationship between transactional leadership and OCB to be positive to the extent that idiocentrism increases and negative to the extent that allocentrism increases. Implications of these findings for research and practice are discussed. PMID:26893538

  13. Spatial and temporal information fusion for crop condition monitoring

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop growth condition information is critical for crop management and yield estimation. In order to monitor crop conditions from space, high spatial and temporal resolution remote sensing data are required. Data fusion approach provides a way to generate such data set from multiple remote sensing da...

  14. Decoding Rich Spatial Information with High Temporal Resolution

    PubMed Central

    Stokes, Mark G.; Wolff, Michael J.; Spaak, Eelke

    2015-01-01

    New research suggests that magnetoencephalography (MEG) contains rich spatial information for decoding neural states. Even small differences in the angle of neighbouring dipoles generate subtle, but statistically separable field patterns. This implies MEG (and electroencephalography: EEG) is ideal for decoding neural states with high-temporal resolution in the human brain. PMID:26440122

  15. Where and Why There? Spatial Thinking with Geographic Information Systems

    ERIC Educational Resources Information Center

    Milson, Andrew J.; Curtis, Mary D.

    2009-01-01

    The authors developed and implemented a project for high school geography students that modeled the processes in a site selection analysis using Geographic Information Systems (GIS). They sought to explore how spatial thinking could be fostered by using the MyWorld GIS software that was designed specifically for educational uses. The task posed…

  16. Time walkers and spatial dynamics of aging information.

    PubMed

    Lizana, L; Rosvall, M; Sneppen, K

    2010-01-29

    The distribution of information is essential for a living system's ability to coordinate and adapt. Random walkers are often used to model this distribution process and, in doing so, one effectively assumes that information maintains its relevance over time. But the value of information in social and biological systems often decays and must continuously be updated. To capture the spatial dynamics of aging information, we introduce time walkers. A time walker moves like a random walker, but interacts with traces left by other walkers, some representing older information, some newer. The traces form a navigable information landscape which we visualize as a river network. We quantify the dynamical properties of time walkers, and the quality of the information left behind, on a two-dimensional lattice. We show that searching in this landscape is superior to random searching. PMID:20366697

  17. Visual cortical prosthesis with a geomagnetic compass restores spatial navigation in blind rats.

    PubMed

    Norimoto, Hiroaki; Ikegaya, Yuji

    2015-04-20

    Allocentric sense is one of the major components that underlie spatial navigation. In blind patients, the difficulty in spatial exploration is attributed, at least partly, to the deficit of absolute direction perception. In support of this notion, we announce that blind adult rats can perform spatial tasks normally when externally provided with real-time feedback of their head directions. Head-mountable microstimulators coupled with a digital geomagnetic compass were bilaterally implanted in the primary visual cortex of adult rats whose eyelids had been sutured. These "blind" rats were trained to seek food pellets in a T-shaped maze or a more complicated maze. Within tens of trials, they learned to manage the geomagnetic information source to solve the mazes. Their performance levels and navigation strategies were similar to those of normal sighted, intact rats. Thus, blind rats can recognize self-location through extrinsically provided stereotactic cues. PMID:25843028

  18. Extracting spatial information from networks with low-order eigenvectors

    NASA Astrophysics Data System (ADS)

    Cucuringu, Mihai; Blondel, Vincent D.; Van Dooren, Paul

    2013-03-01

    We consider the problem of inferring meaningful spatial information in networks from incomplete information on the connection intensity between the nodes of the network. We consider two spatially distributed networks: a population migration flow network within the US, and a network of mobile phone calls between cities in Belgium. For both networks we use the eigenvectors of the Laplacian matrix constructed from the link intensities to obtain informative visualizations and capture natural geographical subdivisions. We observe that some low-order eigenvectors localize very well and seem to reveal small geographically cohesive regions that match remarkably well with political and administrative boundaries. We discuss possible explanations for this observation by describing diffusion maps and localized eigenfunctions. In addition, we discuss a possible connection with the weighted graph cut problem, and provide numerical evidence supporting the idea that lower-order eigenvectors point out local cuts in the network. However, we do not provide a formal and rigorous justification for our observations.

  19. Disentangling Overlapping Astronomical Sources Using Spatial and Spectral Information

    NASA Astrophysics Data System (ADS)

    Jones, David E.; Kashyap, Vinay L.; van Dyk, David A.

    2015-08-01

    We present a powerful new algorithm that combines both spatial information (event locations and the point-spread function) and spectral information (photon energies) to separate photons from overlapping sources. We use Bayesian statistical methods to simultaneously infer the number of overlapping sources, to probabilistically separate the photons among the sources, and to fit the parameters describing the individual sources. Using the Bayesian joint posterior distribution, we are able to coherently quantify the uncertainties associated with all these parameters. The advantages of combining spatial and spectral information are demonstrated through a simulation study. The utility of the approach is then illustrated by analysis of observations of FK Aqr and FL Aqr with the XMM-Newton Observatory and the central region of the Orion Nebula Cluster with the Chandra X-ray Observatory.

  20. Patterns of preserved and impaired spatial memory in a case of developmental amnesia

    PubMed Central

    Rosenbaum, R. Shayna; Cassidy, Benjamin N.; Herdman, Katherine A.

    2015-01-01

    The hippocampus is believed to have evolved to support allocentric spatial representations of environments as well as the details of personal episodes that occur within them, whereas other brain structures are believed to support complementary egocentric spatial representations. Studies of patients with adult-onset lesions lend support to these distinctions for newly encountered places but suggest that with time and/or experience, schematic aspects of environments can exist independent of the hippocampus. Less clear is the quality of spatial memories acquired in individuals with impaired episodic memory in the context of a hippocampal system that did not develop normally. Here we describe a detailed investigation of the integrity of spatial representations of environments navigated repeatedly over many years in the rare case of H.C., a person with congenital absence of the mammillary bodies and abnormal hippocampal and fornix development. H.C. and controls who had extensive experience navigating the residential and downtown areas known to H.C. were tested on mental navigation tasks that assess the identity, location, and spatial relations among landmarks, and the ability to represent routes. H.C. was able to represent distances and directions between familiar landmarks and provide accurate, though inefficient, route descriptions. However, difficulties producing detailed spatial features on maps and accurately ordering more than two landmarks that are in close proximity to one another along a route suggest a spatial representation that includes only coarse, schematic information that lacks coherence and that cannot be used flexibly. This pattern of performance is considered in the context of other areas of preservation and impairment exhibited by H.C. and suggests that the allocentric-egocentric dichotomy with respect to hippocampal and extended hippocampal system function may need to be reconsidered. PMID:26029074

  1. CCSI: a database providing chromatin-chromatin spatial interaction information.

    PubMed

    Xie, Xiaowei; Ma, Wenbin; Songyang, Zhou; Luo, Zhenhua; Huang, Junfeng; Dai, Zhiming; Xiong, Yuanyan

    2016-01-01

    Distal regulatory elements have been shown to regulate gene transcription through spatial interactions, and single nucleotide polymorphisms (SNPs) are linked with distal gene expression by spatial proximity, which helps to explain the causal role of disease-associated SNPs in non-coding region. Therefore, studies on spatial interactions between chromatin have created a new avenue for elucidating the mechanism of transcriptional regulation in disease pathogenesis. Recently, a growing number of chromatin interactions have been revealed by means of 3C, 4C, 5C, ChIA-PET and Hi-C technologies. To interpret and utilize these interactions, we constructed chromatin-chromatin spatial interaction (CCSI) database by integrating and annotating 91 sets of chromatin interaction data derived from published literature, UCSC database and NCBI GEO database, resulting in a total of 3,017,962 pairwise interactions (false discovery rate < 0.05), covering human, mouse and yeast. A web interface has been designed to provide access to the chromatin interactions. The main features of CCSI are (i) showing chromatin interactions and corresponding genes, enhancers and SNPs within the regions in the search page; (ii) offering complete interaction datasets, enhancer and SNP information in the download page; and (iii) providing analysis pipeline for the annotation of interaction data. In conclusion, CCSI will facilitate exploring transcriptional regulatory mechanism in disease pathogenesis associated with spatial interactions among genes, regulatory regions and SNPs. Database URL: http://songyanglab.sysu.edu.cn/ccsi. PMID:26868054

  2. CCSI: a database providing chromatin–chromatin spatial interaction information

    PubMed Central

    Ma, Wenbin; Songyang, Zhou; Luo, Zhenhua; Huang, Junfeng; Dai, Zhiming; Xiong, Yuanyan

    2016-01-01

    Distal regulatory elements have been shown to regulate gene transcription through spatial interactions, and single nucleotide polymorphisms (SNPs) are linked with distal gene expression by spatial proximity, which helps to explain the causal role of disease-associated SNPs in non-coding region. Therefore, studies on spatial interactions between chromatin have created a new avenue for elucidating the mechanism of transcriptional regulation in disease pathogenesis. Recently, a growing number of chromatin interactions have been revealed by means of 3C, 4C, 5C, ChIA-PET and Hi-C technologies. To interpret and utilize these interactions, we constructed chromatin–chromatin spatial interaction (CCSI) database by integrating and annotating 91 sets of chromatin interaction data derived from published literature, UCSC database and NCBI GEO database, resulting in a total of 3 017 962 pairwise interactions (false discovery rate < 0.05), covering human, mouse and yeast. A web interface has been designed to provide access to the chromatin interactions. The main features of CCSI are (i) showing chromatin interactions and corresponding genes, enhancers and SNPs within the regions in the search page; (ii) offering complete interaction datasets, enhancer and SNP information in the download page; and (iii) providing analysis pipeline for the annotation of interaction data. In conclusion, CCSI will facilitate exploring transcriptional regulatory mechanism in disease pathogenesis associated with spatial interactions among genes, regulatory regions and SNPs. Database URL: http://songyanglab.sysu.edu.cn/ccsi PMID:26868054

  3. Representing spatial information in a computational model for network management

    NASA Technical Reports Server (NTRS)

    Blaisdell, James H.; Brownfield, Thomas F.

    1994-01-01

    While currently available relational database management systems (RDBMS) allow inclusion of spatial information in a data model, they lack tools for presenting this information in an easily comprehensible form. Computer-aided design (CAD) software packages provide adequate functions to produce drawings, but still require manual placement of symbols and features. This project has demonstrated a bridge between the data model of an RDBMS and the graphic display of a CAD system. It is shown that the CAD system can be used to control the selection of data with spatial components from the database and then quickly plot that data on a map display. It is shown that the CAD system can be used to extract data from a drawing and then control the insertion of that data into the database. These demonstrations were successful in a test environment that incorporated many features of known working environments, suggesting that the techniques developed could be adapted for practical use.

  4. The Cognitive Architecture of Spatial Navigation: Hippocampal and Striatal Contributions.

    PubMed

    Chersi, Fabian; Burgess, Neil

    2015-10-01

    Spatial navigation can serve as a model system in cognitive neuroscience, in which specific neural representations, learning rules, and control strategies can be inferred from the vast experimental literature that exists across many species, including humans. Here, we review this literature, focusing on the contributions of hippocampal and striatal systems, and attempt to outline a minimal cognitive architecture that is consistent with the experimental literature and that synthesizes previous related computational modeling. The resulting architecture includes striatal reinforcement learning based on egocentric representations of sensory states and actions, incidental Hebbian association of sensory information with allocentric state representations in the hippocampus, and arbitration of the outputs of both systems based on confidence/uncertainty in medial prefrontal cortex. We discuss the relationship between this architecture and learning in model-free and model-based systems, episodic memory, imagery, and planning, including some open questions and directions for further experiments. PMID:26447573

  5. Individual differences in spatial cognition influence mental simulation of language.

    PubMed

    Vukovic, Nikola; Williams, John N

    2015-09-01

    The factors that contribute to perceptual simulation during sentence comprehension remain underexplored. Extant research on perspective taking in language has largely focused on linguistic constraints, such as the role of pronouns in guiding perspective adoption. In the present study, we identify preferential usage of egocentric and allocentric reference frames in individuals, and test the two groups on a standard sentence-picture verification task. Across three experiments, we show that individual biases in spatial reference frame adoption observed in non-linguistic tasks influence visual simulation of perspective in language. Our findings suggest that typically reported grand-averaged effects may obscure important between-subject differences, and support proposals arguing for representational pluralism, where perceptual information is integrated dynamically and in a way that is sensitive to contextual and especially individual constraints. PMID:26036923

  6. Associations of collectivism with relationship commitment, passion, and mate preferences: opposing roles of parental influence and family allocentrism.

    PubMed

    Bejanyan, Kathrine; Marshall, Tara C; Ferenczi, Nelli

    2015-01-01

    In collectivist cultures, families tend to be characterized by respect for parental authority and strong, interdependent ties. Do these aspects of collectivism exert countervailing pressures on mate choices and relationship quality? In the present research, we found that collectivism was associated with greater acceptance of parental influence over mate choice, thereby driving relationship commitment down (Studies 1 and 2), but collectivism was also associated with stronger family ties (referred to as family allocentrism), which drove commitment up (Study 2). Along similar lines, Study 1 found that collectivists' greater acceptance of parental influence on mate choice contributed to their reduced relationship passion, whereas Study 2 found that their greater family allocentrism may have enhanced their passion. Study 2 also revealed that collectivists may have reported a smaller discrepancy between their own preferences for mates high in warmth and trustworthiness and their perception of their parents' preferences for these qualities because of their stronger family allocentrism. However, their higher tolerance of parental influence may have also contributed to a smaller discrepancy in their mate preferences versus their perceptions of their parents' preferences for qualities signifying status and resources. Implications for the roles of collectivism, parental influence, and family allocentrism in relationship quality and mate selection will be discussed. PMID:25719563

  7. Associations of Collectivism with Relationship Commitment, Passion, and Mate Preferences: Opposing Roles of Parental Influence and Family Allocentrism

    PubMed Central

    Bejanyan, Kathrine; Marshall, Tara C.; Ferenczi, Nelli

    2015-01-01

    In collectivist cultures, families tend to be characterized by respect for parental authority and strong, interdependent ties. Do these aspects of collectivism exert countervailing pressures on mate choices and relationship quality? In the present research, we found that collectivism was associated with greater acceptance of parental influence over mate choice, thereby driving relationship commitment down (Studies 1 and 2), but collectivism was also associated with stronger family ties (referred to as family allocentrism), which drove commitment up (Study 2). Along similar lines, Study 1 found that collectivists’ greater acceptance of parental influence on mate choice contributed to their reduced relationship passion, whereas Study 2 found that their greater family allocentrism may have enhanced their passion. Study 2 also revealed that collectivists may have reported a smaller discrepancy between their own preferences for mates high in warmth and trustworthiness and their perception of their parents’ preferences for these qualities because of their stronger family allocentrism. However, their higher tolerance of parental influence may have also contributed to a smaller discrepancy in their mate preferences versus their perceptions of their parents’ preferences for qualities signifying status and resources. Implications for the roles of collectivism, parental influence, and family allocentrism in relationship quality and mate selection will be discussed. PMID:25719563

  8. 3D spatial information infrastructure: The case of Port Rotterdam

    NASA Astrophysics Data System (ADS)

    Zlatanova, S.; Beetz, J.

    2012-10-01

    The development and maintenance of the infrastructure, facilities, logistics and other assets of the Port of Rotterdam requires a broad spectrum of heterogeneous information. This information concerns features, which are spatially distributed above ground, underground, in the air and in the water. The data are managed in a variety of data models with varying levels of dimensionality, granularity, accuracy and up-to-dateness. Additionally increasing number of 3D design models is becoming available. This complexity of tasks and diversity of information challenges the Port authority to look for more advanced 3D solutions. This paper presents research in progress related to developing a 3D SII in support of information and process management within the Port of Rotterdam.

  9. An information theory analysis of spatial decisions in cognitive development

    PubMed Central

    Scott, Nicole M.; Sera, Maria D.; Georgopoulos, Apostolos P.

    2015-01-01

    Performance in a cognitive task can be considered as the outcome of a decision-making process operating across various knowledge domains or aspects of a single domain. Therefore, an analysis of these decisions in various tasks can shed light on the interplay and integration of these domains (or elements within a single domain) as they are associated with specific task characteristics. In this study, we applied an information theoretic approach to assess quantitatively the gain of knowledge across various elements of the cognitive domain of spatial, relational knowledge, as a function of development. Specifically, we examined changing spatial relational knowledge from ages 5 to 10 years. Our analyses consisted of a two-step process. First, we performed a hierarchical clustering analysis on the decisions made in 16 different tasks of spatial relational knowledge to determine which tasks were performed similarly at each age group as well as to discover how the tasks clustered together. We next used two measures of entropy to capture the gradual emergence of order in the development of relational knowledge. These measures of “cognitive entropy” were defined based on two independent aspects of chunking, namely (1) the number of clusters formed at each age group, and (2) the distribution of tasks across the clusters. We found that both measures of entropy decreased with age in a quadratic fashion and were positively and linearly correlated. The decrease in entropy and, therefore, gain of information during development was accompanied by improved performance. These results document, for the first time, the orderly and progressively structured “chunking” of decisions across the development of spatial relational reasoning and quantify this gain within a formal information-theoretic framework. PMID:25698915

  10. An information theory analysis of spatial decisions in cognitive development.

    PubMed

    Scott, Nicole M; Sera, Maria D; Georgopoulos, Apostolos P

    2015-01-01

    Performance in a cognitive task can be considered as the outcome of a decision-making process operating across various knowledge domains or aspects of a single domain. Therefore, an analysis of these decisions in various tasks can shed light on the interplay and integration of these domains (or elements within a single domain) as they are associated with specific task characteristics. In this study, we applied an information theoretic approach to assess quantitatively the gain of knowledge across various elements of the cognitive domain of spatial, relational knowledge, as a function of development. Specifically, we examined changing spatial relational knowledge from ages 5 to 10 years. Our analyses consisted of a two-step process. First, we performed a hierarchical clustering analysis on the decisions made in 16 different tasks of spatial relational knowledge to determine which tasks were performed similarly at each age group as well as to discover how the tasks clustered together. We next used two measures of entropy to capture the gradual emergence of order in the development of relational knowledge. These measures of "cognitive entropy" were defined based on two independent aspects of chunking, namely (1) the number of clusters formed at each age group, and (2) the distribution of tasks across the clusters. We found that both measures of entropy decreased with age in a quadratic fashion and were positively and linearly correlated. The decrease in entropy and, therefore, gain of information during development was accompanied by improved performance. These results document, for the first time, the orderly and progressively structured "chunking" of decisions across the development of spatial relational reasoning and quantify this gain within a formal information-theoretic framework. PMID:25698915

  11. Spatially Informed Plant PRA Models for Security Assessment

    SciTech Connect

    Wheeler, Timothy A.; Thomas, Willard; Thornsbury, Eric

    2006-07-01

    Traditional risk models can be adapted to evaluate plant response for situations where plant systems and structures are intentionally damaged, such as from sabotage or terrorism. This paper describes a process by which traditional risk models can be spatially informed to analyze the effects of compound and widespread harsh environments through the use of 'damage footprints'. A 'damage footprint' is a spatial map of regions of the plant (zones) where equipment could be physically destroyed or disabled as a direct consequence of an intentional act. The use of 'damage footprints' requires that the basic events from the traditional probabilistic risk assessment (PRA) be spatially transformed so that the failure of individual components can be linked to the destruction of or damage to specific spatial zones within the plant. Given the nature of intentional acts, extensive modifications must be made to the risk models to account for the special nature of the 'initiating events' associated with deliberate adversary actions. Intentional acts might produce harsh environments that in turn could subject components and structures to one or more insults, such as structural, fire, flood, and/or vibration and shock damage. Furthermore, the potential for widespread damage from some of these insults requires an approach that addresses the impacts of these potentially severe insults even when they occur in locations distant from the actual physical location of a component or structure modeled in the traditional PRA. (authors)

  12. Spatial Modeling of Colonic Lesions With Geographic Information Systems

    PubMed Central

    Imanieh, Mohammad Hadi; Goli, Ali; Imanieh, Mohammad Hossein; Geramizadeh, Bita

    2014-01-01

    Background: Geographic information system (GIS) software has been used in health care systems to display and analyze spatial pattern of diseases and health services. Objectives: This study was performed to assess spatial patterns of colon’s pathologic lesions based on the pathologic reports and assess whether it is possible to use GIS software in health services. Patients and Methods: Archives of pathology of Namazi and Faghihi hospitals, two main referral centers of south-west of Iran, were obtained and reviewed between January 2009 and September 2011 for biopsy reports of patients who underwent colonoscopy. Abnormal biopsies were categorized into five different subgroups according to the type of pathologic specimens. By GIS, spatial patterns of colon biopsies were plotted in different maps and spatial auto-correlation of colon biopsies was calculated using the Moran’s Index. Results: A total of 4815 biopsies from 2663 different patients were reviewed, 53.8% of which were men. Abnormal biopsies were 2781 of all specimens (57.8%). Neoplastic lesions, inflammatory bowel diseases and polyps were 9.3%, 19.3% and 29.2% of total biopsies, respectively. Pathologic biopsies were more common in the distal colon. Maps of all biopsies and maps of specific pathologies were manifested in GIS. Conclusions: Our study showed that left-sided lesions are still more common in the Iranian population. On the other hand, surveying the right side of colon is as important as the distal part, which necessitates total colonoscopy. PMID:25763265

  13. Digital spatial soil and land information for agriculture development

    NASA Astrophysics Data System (ADS)

    Sharma, R. K.; Laghathe, Pankaj; Meena, Ranglal; Barman, Alok Kumar; Das, Satyendra Nath

    2006-12-01

    Natural resource management calls for study of natural system prevailing in the country. In India floods and droughts visit regularly, causing extensive damages of natural wealth including agriculture that are crucial for sustenance of economic growth. The Indian Sub-continent drained by many major rivers and their tributaries where watershed, the hydrological unit forms a natural system that allows management and development of land resources following natural harmony. Acquisition of various kinds and levels of soil and land characteristics using both conventional and remote sensing techniques and subsequent development of digital spatial data base are essential to evolve strategy for planning watershed development programmes, their monitoring and impact evaluation. The multi-temporal capability of remote sensing sensors helps to update the existing data base which are of dynamic in nature. The paper outlines the concept of spatial data base development, generation using remote sensing techniques, designing of data structure, standardization and integration with watershed layers and various non spatial attribute data for various applications covering watershed development planning, alternate land use planning, soil and water conservation, diversified agriculture practices, generation of soil health card, soil and land reclamation, etc. The soil and land characteristics are vital to derive various interpretative groupings or master table that helps to generate the desired level of information of various clients using the GIS platform. The digital spatial data base on soils and watersheds generated by All India Soil and Land Use Survey will act as a sub-server of the main GIS based Web Server being hoisted by the planning commission for application of spatial data for planning purposes under G2G domain. It will facilitate e-governance for natural resource management using modern technology.

  14. Study on architecture and implementation of adaptive spatial information service

    NASA Astrophysics Data System (ADS)

    Yu, Zhuoyuan; Wang, Yingjie; Luo, Bin

    2007-06-01

    More and more geo-spatial information has been disseminated to the Internet based on WebGIS architecture. Some of these online mapping applications have already been widely used in recent years, such as Google map, MapQuest, go2map, mapbar. However, due to the limitation of web map technology and transmit speed of large geo-spatial data through the Internet, most of these web map systems employ (pyramid-indexed) raster map modeling technology. This method can shorten server's response time but largely reduces the flexibility and visualization effect of the web map provided. It will be difficult for them to adaptively change the map contents or map styles for variant user demands. This paper propose a new system architecture for adaptive web map service by integrating latest network technology and web map technology, such as SVG, Ajax, user modeling. Its main advantages include: Firstly, it is user customized. In this proposed map system, user can design the map contents, styles and interfaces online by themselves; secondly, it is more intelligent. It can record user interactive actions with the system, analyze user profiles, predict user behavior. User's interests will be obtained and tasks will be suggested based on different user models, which are generated from the system. For instance, if a new user login in, the nearest user model will be matched and some interactive suggestions will be provided by the system for the user. It is a more powerful and efficient way for spatial information sharing. This paper first discusses the main system architecture of adaptive spatial information service which consists of three parts: user layer, map application layer and database layer. User layer is distributed on client side which includes Web map (SVG) browser, map renderer and map visualization component. Application layer includes map application server, user interface generation, user analysis and user modeling, etc. Based on user models, map content, style and user

  15. Remodeling census population with spatial information from Landsat TM imagery

    USGS Publications Warehouse

    Yuan, Y.; Smith, R.M.; Limp, W.F.

    1997-01-01

    In geographic information systems (GIS) studies there has been some difficulty integrating socioeconomic and physiogeographic data. One important type of socioeconomic data, census data, offers a wide range of socioeconomic information, but is aggregated within arbitrary enumeration districts (EDs). Values reflect either raw counts or, when standardized, the mean densities in the EDs. On the other hand, remote sensing imagery, an important type of physiogeographic data, provides large quantities of information with more spatial details than census data. Based on the dasymetric mapping principle, this study applies multivariable regression to examine the correlation between population counts from census and land cover types. The land cover map is classified from LandSat TM imagery. The correlation is high. Census population counts are remodeled to a GIS raster layer based on the discovered correlations coupled with scaling techniques, which offset influences from other than land cover types. The GIS raster layer depicts the population distribution with much more spatial detail than census data offer. The resulting GIS raster layer is ready to be analyzed or integrated with other GIS data. ?? 1998 Elsevier Science Ltd. All rights reserved.

  16. Virtual-real spatial information visualization registration using affine representations

    NASA Astrophysics Data System (ADS)

    Wu, Xueling; Ren, Fu; Du, Qingyun

    2009-10-01

    Virtual-real registration in Outdoor Augmented Reality is committed to enhance user's spatial cognition by overlaying virtual geographical objects on real scene. According to analyze fiducial detection registration method in indoor AR, for the purpose of avoiding complex and tedious process of position tracking and camera calibration in traditional registration methods, it puts forward and practices a virtual-real spatial information visualization registration method using affine representations. Based on the observation from Koenderink and van Doorn, Ullman and Basri in 1991 which is given a set of four or more non-coplanar 3D points, the projection of all points in the set can be computed as a linear combination of the projection of just four of the points, it sets up global affine coordinate system in light of world coordinates, camera coordinates and virtual coordinates and extracts four feature points from scene image and calculates the global affine coordinates of key points of virtual objects. Then according to a linear homogeneous coordinates of the four feature point's projection, it calculates projection pixel coordinates of key points of virtual objects. In addition, it proposes an approach to obtain pixel relative depth for hidden surface removal. Finally, by a case study, it verifies the feasibility and efficiency of the registration methods. The method would not only explore a new research direction for Geographical Information Science, but also would provide location-based information and services for outdoor AR.

  17. Daytime Sleep Enhances Consolidation of the Spatial but Not Motoric Representation of Motor Sequence Memory

    PubMed Central

    Albouy, Geneviève; Fogel, Stuart; Pottiez, Hugo; Nguyen, Vo An; Ray, Laura; Lungu, Ovidiu; Carrier, Julie; Robertson, Edwin; Doyon, Julien

    2013-01-01

    Motor sequence learning is known to rely on more than a single process. As the skill develops with practice, two different representations of the sequence are formed: a goal representation built under spatial allocentric coordinates and a movement representation mediated through egocentric motor coordinates. This study aimed to explore the influence of daytime sleep (nap) on consolidation of these two representations. Through the manipulation of an explicit finger sequence learning task and a transfer protocol, we show that both allocentric (spatial) and egocentric (motor) representations of the sequence can be isolated after initial training. Our results also demonstrate that nap favors the emergence of offline gains in performance for the allocentric, but not the egocentric representation, even after accounting for fatigue effects. Furthermore, sleep-dependent gains in performance observed for the allocentric representation are correlated with spindle density during non-rapid eye movement (NREM) sleep of the post-training nap. In contrast, performance on the egocentric representation is only maintained, but not improved, regardless of the sleep/wake condition. These results suggest that motor sequence memory acquisition and consolidation involve distinct mechanisms that rely on sleep (and specifically, spindle) or simple passage of time, depending respectively on whether the sequence is performed under allocentric or egocentric coordinates. PMID:23300993

  18. Remembering the Past and Imagining the Future: A Neural Model of Spatial Memory and Imagery

    ERIC Educational Resources Information Center

    Byrne, Patrick; Becker, Suzanna; Burgess, Neil

    2007-01-01

    The authors model the neural mechanisms underlying spatial cognition, integrating neuronal systems and behavioral data, and address the relationships between long-term memory, short-term memory, and imagery, and between egocentric and allocentric and visual and ideothetic representations. Long-term spatial memory is modeled as attractor dynamics…

  19. Organisational aspects of spatial information infrastructure in Poland

    NASA Astrophysics Data System (ADS)

    Bielecka, Elzbieta; Zwirowicz-Rutkowska, Agnieszka

    2013-06-01

    One of the more important elements of spatial information infrastructure is the organisational structure defining the obligations and dependencies between stakeholders that are responsible for the infrastructure. Many SDI practitioners and theoreticians emphasise that its influence on the success or failure of activities undertaken is significantly greater than that of technical aspects. Being aware of the role of the organisational structure in the creating, operating and maintenance of spatial information infrastructure (SII), Polish legislators placed appropriate regulations in the Spatial Information Infrastructure Act, being the transposition of the INSPIRE Directive into Polish Law. The principal spatial information infrastructure stakeholders are discussed in the article and also the scope of cooperation between them. The tasks and relationships between stakeholders are illustrated in UML, in both the use case and the class diagram. Mentioned also are the main problems and obstructions resulting from imprecise legal regulations. Jednym z istotniejszych komponentów infrastruktury informacji przestrzennej (IIP) jest struktura organizacyjna określająca m.in. zależności pomiędzy organizacjami tworzącymi infrastrukturę. Wielu praktyków i teoretyków SDI podkreśla, że wpływ aspektów organizacyjnych na sukces lub porażkę SDI jest dużo większy niż elementów technicznych. Mając świadomość znaczącej roli struktury organizacyjnej w tworzeniu, funkcjonowaniu i zarządzaniu infrastrukturą przestrzenną w Polsce, legislatorzy umieścili odpowiednie zapisy w ustawie z dnia 4 marca 2010 r. o infrastrukturze informacji przestrzennej, będącej transpozycją dyrektywy INSPIRE do prawa polskiego. W artykule omówiono strukturę organizacyjną IIP w Polsce, podając (m.in. w postaci diagramów UML) obowiązki poszczególnych organów administracji zaangażowanych w jej budowę i rozwój, a także omówiono zależności i zakres współpracy pomi

  20. Words and Maps: Developmental Changes in Mental Models of Spatial Information Acquired from Descriptions and Depictions

    ERIC Educational Resources Information Center

    Uttal, David H.; Fisher, Joan A.; Taylor, Holly A.

    2006-01-01

    People acquire spatial information from many sources, including maps, verbal descriptions, and navigating in the environment. The different sources present spatial information in different ways. For example, maps can show many spatial relations simultaneously, but in a description, each spatial relation must be presented sequentially. The present…

  1. Instructional geographic information science Map overlay and spatial abilities

    NASA Astrophysics Data System (ADS)

    Tricot, Thomas Alexander, II

    The fundamental goal of this study is to determine if the complex spatial concept of map overlay can be effectively learned by young adolescents through the utilization of an instructional technique based within the foundations of Instructional Geographic Information Science (InGIScience). Percent correct and reaction times were the measures used to analyze the ability of young adolescents to learn the intersect, erase, and union functions of map overlay. The ability to solve for missing inputs, output, or function was also analyzed. Young adolescents of the test group scored higher percent correct and recorded faster reaction times than those of the control group or adults of the expert group by the end of the experiment. The intersect function of map overlay was more difficult in terms of percent correct and reaction time than the erase or union functions. Solving for the first or second input consistently resulted in lower percent correct and higher reaction times throughout the experiment. No overall performance differences were shown to exist between males and females. Results of a subjective "real-world" test also indicated learning by young adolescents. This study has shown that the practice of repetitive instruction and testing has proven effective for enhancing spatial abilities with regard to the map overlay concept. This study found that with practice, young adolescents can learn the map overlay concept and perform at levels equal to or greater than adults. This study has helped to answer the question of whether this development of spatial abilities is possible.

  2. Spatial Information Technology Center at Fulton-Montgomery Community College

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The Spatial Information Technology Center (SITC) at Fulton-Montgomery Community College (FMCC) continued to fulfill its mission and charter by successfully completing its fourth year of operations under Congressional funding and NASA sponsorship. Fourth year operations (01 Oct 03 - 30 Sep 04) have been funded and conducted utilizing an authorized Research Grant NAG 13-02053 (via a one-year no-cost extension expiring Sep 04). Drawdown and reporting of fiscal activities for SITC operations passes through the Institute for the Application of Geo-spatial Technology (IAGT) at Cayuga Community College in Auburn, New York. Fiscal activity of the Center is reported quarterly via SF 272 to IAGT, this report contains an overview and expenditures for the remaining funds of NAG 13-02053. NAG 13-02053, slated for operating costs for the fiscal year FY02-03, received a one-year no-cost extension. SITC also received permission to use remaining funds for salaries and benefits through December 31,2004. The IAGT receives no compensation for administrative costs. This report includes addendums for the NAG award as required by federal guidelines. Attached are the signed Report of New Technology/Inventions and a Final Property Report. As an academic, economic, and workforce development program, the Center has made significant strides in bringing the technology, knowledge and applications of the spatial information technology field to the region it serves. Through the mission of the Center, the region's communities have become increasingly aware of the benefits of Geospatial technology, particularly in the region s K-12 arena. SITC continues to positively affect the region's education, employment and economic development, while expanding its services and operations.

  3. Reference frames in allocentric representations are invariant across static and active encoding

    PubMed Central

    Chan, Edgar; Baumann, Oliver; Bellgrove, Mark A.; Mattingley, Jason B.

    2013-01-01

    An influential model of spatial memory—the so-called reference systems account—proposes that relationships between objects are biased by salient axes (“frames of reference”) provided by environmental cues, such as the geometry of a room. In this study, we sought to examine the extent to which a salient environmental feature influences the formation of spatial memories when learning occurs via a single, static viewpoint and via active navigation, where information has to be integrated across multiple viewpoints. In our study, participants learned the spatial layout of an object array that was arranged with respect to a prominent environmental feature within a virtual arena. Location memory was tested using judgments of relative direction. Experiment 1A employed a design similar to previous studies whereby learning of object-location information occurred from a single, static viewpoint. Consistent with previous studies, spatial judgments were significantly more accurate when made from an orientation that was aligned, as opposed to misaligned, with the salient environmental feature. In Experiment 1B, a fresh group of participants learned the same object-location information through active exploration, which required integration of spatial information over time from a ground-level perspective. As in Experiment 1A, object-location information was organized around the salient environmental cue. Taken together, the findings suggest that the learning condition (static vs. active) does not affect the reference system employed to encode object-location information. Spatial reference systems appear to be a ubiquitous property of spatial representations, and might serve to reduce the cognitive demands of spatial processing. PMID:24009595

  4. Spatial Information in local society's cultural conservation and research

    NASA Astrophysics Data System (ADS)

    Jang, J.-J.; Liao, H.-M.; Fan, I.-C.

    2015-09-01

    Center for Geographic Information Science, Research Center for Humanities and Social Sciences,Academia Sinica (GIS center), Coordinate short-, medium-, and long-term operations of multidisciplinary researches focusing on related topics in the sciences and humanities. Based on the requirements of multi-disciplinary research applications, sustain collection and construction of sustaining and unifying spatial base data and knowledge and building of spatial data infrastructure. Since the 1990s, GIS center build geographic information platform: "Time and space infrastructure of Chinese civilization" (Chinese Civilizationin Time and Space, CCTS) and "Taiwan History and Culture Map" (Taiwan History and Culture in Time and Space, THCTS) . the goal of both system is constructing an integrated GIS-based application infrastructure on the spatial extent of China and Taiwan, in the timeframe of Chinese and Taiwanese history, and with the contents of Chinese and Taiwanese civilization. Base on THCTS, we began to build Cultural Resources GIS(CRGIS, http://crgis.rchss.sinica.edu.tw) in 2006, to collect temples, historic Monuments, historic buildings, old trees, wind lions god and other cultural resource in Taiwan, and provide a platform for the volunteers to make for all types of tangible, intangible cultural resources, add, edit, organize and query data via Content Management System(CMS) . CRGIS collected aggregated 13,000 temples, 4,900 churches. On this basis, draw a variety of religious beliefs map-multiple times Temple distributions, different main god distributions, church distribution. Such as Mazu maps, Multiple times temple distributions map (before 1823, 1823-1895,1895-1949,1949-2015 years) at Taijiang inner sea areas in Tainan. In Taiwan, there is a religious ritual through folk activities for a period ranging from one day to several days, passing specific geospatial range and passes through some temples or houses. Such an important folk activity somewhat similar to

  5. Spatial Information Technology Center at Fulton-Montgomery Community College

    NASA Technical Reports Server (NTRS)

    Flinton, Michael E.

    2004-01-01

    The Spatial Information Technology Center (SITC) at Fulton-Montgomery Community College (FMCC) continued to fulfill its mission and charter by successfully completing its third year of operations under Congressional funding and NASA sponsorship. Third year operations (01 Oct 02 - 30 Sep 03) have been funded and conducted utilizing two authorized Research Grants NAG 13-00043 (via a one-year no-cost extension expiring Sep 03) and NAG 13-02053 (one-year no-cost extension expiring Sep 04). Drawdowns and reporting of fiscal activities for SlTC operations continues to pass through the Institute for the Application of Geo-spatial Technology (IAGT) at Cayuga Community College in Auburn, New York. Fiscal activity of the Center is reported quarterly via SF 272 to IAGT, thus this report contains only a budgetary overview and forecast of future expenditures for the remaining funds of NAG 13 - 02053. Funds from NAG 13 - 00043 were exhausted during the fourth quarter of fiscal year FY02 - 03, which necessitated initial draw down of NAG 13 - 02053. The IAGT receives no compensation for administrative costs as authorized and approved by NASA in each award budget. This report also includes the necessary addendums for each NAG award, as required by federal guidelines, though no reportable activities took place within this report period. Attached are the signed Report of New Technology/lnventions and a Final Property Report identifying qualifying equipment purchased by the Center. As an academic, economic and workforce development oriented program, the Center has made significant strides in bringing the technology, knowledge and applications of the spatial information technology field to the region it serves. Through the mission of the Center, the region's educational, economic development and work force communities have become increasingly educated to the benefits of spatial (Geospatial) technology, particularly in the region's K-12 arena. SlTC continues to positively affect the

  6. Toward Accessing Spatial Structure from Building Information Models

    NASA Astrophysics Data System (ADS)

    Schultz, C.; Bhatt, M.

    2011-08-01

    Data about building designs and layouts is becoming increasingly more readily available. In the near future, service personal (such as maintenance staff or emergency rescue workers) arriving at a building site will have immediate real-time access to enormous amounts of data relating to structural properties, utilities, materials, temperature, and so on. The critical problem for users is the taxing and error prone task of interpreting such a large body of facts in order to extract salient information. This is necessary for comprehending a situation and deciding on a plan of action, and is a particularly serious issue in time-critical and safety-critical activities such as firefighting. Current unifying building models such as the Industry Foundation Classes (IFC), while being comprehensive, do not directly provide data structures that focus on spatial reasoning and spatial modalities that are required for high-level analytical tasks. The aim of the research presented in this paper is to provide computational tools for higher level querying and reasoning that shift the cognitive burden of dealing with enormous amounts of data away from the user. The user can then spend more energy and time in planning and decision making in order to accomplish the tasks at hand. We present an overview of our framework that provides users with an enhanced model of "built-up space". In order to test our approach using realistic design data (in terms of both scale and the nature of the building models) we describe how our system interfaces with IFC, and we conduct timing experiments to determine the practicality of our approach. We discuss general computational approaches for deriving higher-level spatial modalities by focusing on the example of route graphs. Finally, we present a firefighting scenario with alternative route graphs to motivate the application of our framework.

  7. How the cerebellum may monitor sensory information for spatial representation

    PubMed Central

    Rondi-Reig, Laure; Paradis, Anne-Lise; Lefort, Julie M.; Babayan, Benedicte M.; Tobin, Christine

    2014-01-01

    The cerebellum has already been shown to participate in the navigation function. We propose here that this structure is involved in maintaining a sense of direction and location during self-motion by monitoring sensory information and interacting with navigation circuits to update the mental representation of space. To better understand the processing performed by the cerebellum in the navigation function, we have reviewed: the anatomical pathways that convey self-motion information to the cerebellum; the computational algorithm(s) thought to be performed by the cerebellum from these multi-source inputs; the cerebellar outputs directed toward navigation circuits and the influence of self-motion information on space-modulated cells receiving cerebellar outputs. This review highlights that the cerebellum is adequately wired to combine the diversity of sensory signals to be monitored during self-motion and fuel the navigation circuits. The direct anatomical projections of the cerebellum toward the head-direction cell system and the parietal cortex make those structures possible relays of the cerebellum influence on the hippocampal spatial map. We describe computational models of the cerebellar function showing that the cerebellum can filter out the components of the sensory signals that are predictable, and provides a novelty output. We finally speculate that this novelty output is taken into account by the navigation structures, which implement an update over time of position and stabilize perception during navigation. PMID:25408638

  8. Extracting spatial information from noise measurements of multi-spatial-mode quantum states

    NASA Astrophysics Data System (ADS)

    Marino, A. M.; Clark, J. B.; Glorieux, Q.; Lett, P. D.

    2012-11-01

    We show that it is possible to use the spatial quantum correlations present in twin beams to extract information about the shape of a binary amplitude mask in the path of one of the beams. The scheme, based on noise measurements through homodyne detection, is useful in the regime where the number of photons is low enough that direct detection with a photodiode is difficult but high enough that photon counting is not an option. We find that under some conditions the use of quantum states of light leads to an enhancement of the sensitivity in the estimation of the shape of the mask over what can be achieved with a classical state with equivalent properties (mean photon flux and noise properties). In addition, we show that the level of enhancement that is obtained is a result of the quantum correlations and cannot be explained with only classical correlations.

  9. Spatial Information in local society's cultural conservation and research

    NASA Astrophysics Data System (ADS)

    Jang, J.-J.; Liao, H.-M.; Fan, I.-C.

    2015-09-01

    Center for Geographic Information Science, Research Center for Humanities and Social Sciences,Academia Sinica (GIS center), Coordinate short-, medium-, and long-term operations of multidisciplinary researches focusing on related topics in the sciences and humanities. Based on the requirements of multi-disciplinary research applications, sustain collection and construction of sustaining and unifying spatial base data and knowledge and building of spatial data infrastructure. Since the 1990s, GIS center build geographic information platform: "Time and space infrastructure of Chinese civilization" (Chinese Civilizationin Time and Space, CCTS) and "Taiwan History and Culture Map" (Taiwan History and Culture in Time and Space, THCTS) . the goal of both system is constructing an integrated GIS-based application infrastructure on the spatial extent of China and Taiwan, in the timeframe of Chinese and Taiwanese history, and with the contents of Chinese and Taiwanese civilization. Base on THCTS, we began to build Cultural Resources GIS(CRGIS, http://crgis.rchss.sinica.edu.tw) in 2006, to collect temples, historic Monuments, historic buildings, old trees, wind lions god and other cultural resource in Taiwan, and provide a platform for the volunteers to make for all types of tangible, intangible cultural resources, add, edit, organize and query data via Content Management System(CMS) . CRGIS collected aggregated 13,000 temples, 4,900 churches. On this basis, draw a variety of religious beliefs map-multiple times Temple distributions, different main god distributions, church distribution. Such as Mazu maps, Multiple times temple distributions map (before 1823, 1823-1895,1895-1949,1949-2015 years) at Taijiang inner sea areas in Tainan. In Taiwan, there is a religious ritual through folk activities for a period ranging from one day to several days, passing specific geospatial range and passes through some temples or houses. Such an important folk activity somewhat similar to

  10. Spatial Information Processing: Standards-Based Open Source Visualization Technology

    NASA Astrophysics Data System (ADS)

    Hogan, P.

    2009-12-01

    . Spatial information intelligence is a global issue that will increasingly affect our ability to survive as a species. Collectively we must better appreciate the complex relationships that make life on Earth possible. Providing spatial information in its native context can accelerate our ability to process that information. To maximize this ability to process information, three basic elements are required: data delivery (server technology), data access (client technology), and data processing (information intelligence). NASA World Wind provides open source client and server technologies based on open standards. The possibilities for data processing and data sharing are enhanced by this inclusive infrastructure for geographic information. It is interesting that this open source and open standards approach, unfettered by proprietary constraints, simultaneously provides for entirely proprietary use of this same technology. 1. WHY WORLD WIND? NASA World Wind began as a single program with specific functionality, to deliver NASA content. But as the possibilities for virtual globe technology became more apparent, we found that while enabling a new class of information technology, we were also getting in the way. Researchers, developers and even users expressed their desire for World Wind functionality in ways that would service their specific needs. They want it in their web pages. They want to add their own features. They want to manage their own data. They told us that only with this kind of flexibility, could their objectives and the potential for this technology be truly realized. World Wind client technology is a set of development tools, a software development kit (SDK) that allows a software engineer to create applications requiring geographic visualization technology. 2. MODULAR COMPONENTRY Accelerated evolution of a technology requires that the essential elements of that technology be modular components such that each can advance independent of the other

  11. Prior physical exertion modulates allocentric distance perception: a demonstration of task-irrelevant cross-modal transfer.

    PubMed

    Clark, Ella V; Ward, Nick S; Kuppuswamy, Annapoorna

    2016-08-01

    Physical exertion has been previously shown to influence distance perception in the egocentric framework. In this study, we show that physical exertion influences allocentric distance perception. Twenty healthy volunteers made allocentric line length estimates following varying levels of physical exertion. Each participant was presented with 30 different line lengths ranging from 1 to 12 cm, and each length was presented three times. Each line presentation was preceded by the participant exerting one of the following three levels of their maximal voluntary force (MVF): 20, 50, or 80 % MVF using their hand in the pinch force task. Psychometric curves were obtained for the lines perceived as 'long' following each of the three force levels. Lines that were perceived as 'short' following 20 and 50 % MVF were perceived as 'long' following 80 % MVF; that is, there was a significant leftward shift in the psychometric curve following 80 % MVF when compared to 20 and 50 % MVF. Here, we demonstrate that physical exertion influences perception of distances in the allocentric framework. We discuss our findings with respect to cross-modal interactions, fatigue physiology, peri- and extra-personal space interactions. PMID:27052884

  12. From Geocentrism to Allocentrism: Teaching the Phases of the Moon in a Digital Full-Dome Planetarium

    NASA Astrophysics Data System (ADS)

    Chastenay, Pierre

    2016-02-01

    An increasing number of planetariums worldwide are turning digital, using ultra-fast computers, powerful graphic cards, and high-resolution video projectors to create highly realistic astronomical imagery in real time. This modern technology makes it so that the audience can observe astronomical phenomena from a geocentric as well as an allocentric perspective (the view from space). While the dome creates a sense of immersion, the digital planetarium introduces a new way to teach astronomy, especially for topics that are inherently three-dimensional and where seeing the phenomenon from different points of view is essential. Like a virtual-reality environment, an immersive digital planetarium helps learners create a more scientifically accurate visualization of astronomical phenomena. In this study, a digital planetarium was used to teach the phases of the Moon to children aged 12 to 14. To fully grasp the lunar phases, one must imagine the spherical Moon (as perceived from space), revolving around the Earth while being illuminated by the Sun, and then reconcile this view with the geocentric perspective. Digital planetariums allow learners to have both an allocentric and a geocentric perspective on the lunar phases. Using a Design experiment approach, we tested an educational scenario in which the lunar phases were taught in an allocentric digital planetarium. Based on qualitative data collected before, during, and after the planetarium intervention, we were able to demonstrate that five out of six participants had a better understanding of the lunar phases after the planetarium session.

  13. Extraction of spatial information from remotely sensed image data - an example: gloria sidescan sonar images

    USGS Publications Warehouse

    Chavez, Pat S., Jr.; Gardner, James V.

    1994-01-01

    A method to extract spatial amplitude and variability information from remotely sensed digital imaging data is presented. High Pass Filters (HPFs) are used to compute both a Spatial Amplitude Image/Index (SAI) and Spatial Variability Image/Index (SVI) at the local, intermediate, and regional scales. Used as input to principal component analysis and automatic clustering classification, the results indicate that spatial information at scales other than local is useful in the analysis of remotely sensed data. The resultant multi-spatial data set allows the user to study and analyze an image based more on the complete spatial characteristics of an image than only local textural information.

  14. An evaluation of the spatial resolution of soil moisture information

    NASA Technical Reports Server (NTRS)

    Hardy, K. R.; Cohen, S. H.; Rogers, L. K.; Burke, H. H. K.; Leupold, R. C.; Smallwood, M. D.

    1981-01-01

    Rainfall-amount patterns in the central regions of the U.S. were assessed. The spatial scales of surface features and their corresponding microwave responses in the mid western U.S. were investigated. The usefulness for U.S. government agencies of soil moisture information at scales of 10 km and 1 km. was ascertained. From an investigation of 494 storms, it was found that the rainfall resulting from the passage of most types of storms produces patterns which can be resolved on a 10 km scale. The land features causing the greatest problem in the sensing of soil moisture over large agricultural areas with a radiometer are bodies of water. Over the mid-western portions of the U.S., water occupies less than 2% of the total area, the consequently, the water bodies will not have a significant impact on the mapping of soil moisture. Over most of the areas, measurements at a 10-km resolution would adequately define the distribution of soil moisture. Crop yield models and hydrological models would give improved results if soil moisture information at scales of 10 km was available.

  15. Concept of Spatial Information System for Pieniny geodynamic polygon

    NASA Astrophysics Data System (ADS)

    Pasnikowski, M.; Chmiel, J.; Choromanski, M.; Pillich, A.; Szynal, P.; Galecka, M.; Jarmuz, D.

    2009-04-01

    The poster presents the conception of Spatial Information System (SIS) for geodynamic polygon of Pieniny Klippen Belt (PKB). Geodynamic research of the region, conducted by the staff of Faculty of Geodesy and Cartography of Warsaw University of Technology since the sixties of twentieth century, concern the vertical and horizontal movements and changes of Earth gravity parameters. The collected material all this time, very rich in observations and documentations, as well as further research planned in the region were an inspiration to establish the SIS. The designed system is concerned to be useful basically for collection of the results received so far and planned observation epochs as well. Its target functionality will allow to support the data presentations, analyses of the obtained results and planning process for next research in the future. The proposed conception of the database is described in the poster. The database of the considered SIS contains the following elements: information about geological structures of PKB, localizations of control points of geodynamic polygon and collected observations like: measurements of angles and distances, GNSS, precise and trigonometric levelling, gravimetric. The selected pilot layers of the SIS are based on: DTM, topographic maps, administrative and geologic maps. The data in the project are used to cover and characterize the three tectonic units distinguished in the study area. The ESRI software was used for main part of the work in the project.

  16. Situated student learning and spatial informational analysis for environmental problems

    NASA Astrophysics Data System (ADS)

    Olsen, Timothy Paul

    Ninth and tenth grade high school Biology student research teams used spatial information analysis tools to site a prairie restoration plot on a 55 acre campus during a four-week environment unit. Students made use of innovative technological practices by applying geographic information systems (GIS) approaches to solving environmental and land use problems. Student learning was facilitated by starting with the students' initial conceptions of computing, local landscape and biological environment, and then by guiding them through a problem-based science project process. The project curriculum was framed by the perspective of legitimate peripheral participation (Lave & Wenger, 1991) where students were provided with learning opportunities designed to allow them to act like GIS practitioners. Sociocultural lenses for learning were employed to create accounts of human mental processes that recognize the essential relationship between these processes and their cultural, historical, and institutional settings (Jacob, 1997; Wertsch, 1991). This research investigated how student groups' meaning-making actions were mediated by GIS tools on the periphery of a scientific community of practice. Research observations focused on supporting interpretations of learners' socially constructed actions and the iterative building of assertions from multiple sources. These included the artifacts students produced, the tools they used, the cultural contexts that constrained their activity, and how people begin to adopt ways of speaking (speech genres) of the referent community to negotiate meanings and roles. Students gathered field observations and interpreted attributes of landscape entities from the GIS data to advocate for an environmental decision. However, even while gaining proficiencies with GIS tools, most students did not begin to appropriate roles from the GIS community of practice. Students continued to negotiate their project actions simply as school exercises motivated by

  17. Memory for Complex Visual Objects but Not for Allocentric Locations during the First Year of Life

    ERIC Educational Resources Information Center

    Dupierrix, Eve; Hillairet de Boisferon, Anne; Barbeau, Emmanuel; Pascalis, Olivier

    2015-01-01

    Although human infants demonstrate early competence to retain visual information, memory capacities during infancy remain largely undocumented. In three experiments, we used a Visual Paired Comparison (VPC) task to examine abilities to encode identity (Experiment 1) and spatial properties (Experiments 2a and 2b) of unfamiliar complex visual…

  18. Spatial assessment of Argentinean genetic admixture with geographical information systems.

    PubMed

    Diaz-Lacava, Amalia; Walier, Maja; Penacino, Gustavo; Wienker, Thomas F; Baur, Max P

    2011-08-01

    In recent years there has been much attention to Argentinean population stratification. We were interested in assessing population stratification from a geographical perspective and summarizing it in form of maps. We mapped the genetic admixture of the extant male population in central and northern Argentina on the basis of forensic Y-chromosomal haplotypes. We addressed the question which group of genetically similar individuals is predominant in this area. Haplotypes containing seven Y-chromosomal short tandem repeat polymorphisms (Y-STRs), also known as microsatellites - DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393 - were constructed for 145 individuals, recruited in 10 provinces. 97 distinct haplotypes were clustered into four clusters according to molecular distances. A genetic geostatistical analysis was conducted with the open-source geographical information system GRASS GIS. For each haplotype cluster, the according frequency was spatially interpolated over the total study area. Juxtaposing the interpolation surfaces, we screened point-wisely the maximal frequency as well as the label of the respective cluster. The screening results were combined in one summary map. We repeated this procedure for the second maximal frequencies. The resulting maps subdivide the study area into continuous regions comprising one predominant group of similar haplotypes. The first summary map divides the study area into three regions and the second summary map divides the area into four regions. The results of our analysis indicate that two groups of similar European haplotypes alternatively dominate the largest extension of the Argentinean territory. A third group, including South-American haplotypes, dominates the indigenous northwestern Argentinean area. The last group, including worldwide dispersed haplotypes, preponderates in frequency in second place in central Argentina. Our findings confirm a widespread European paternal ancestry, a substantial Amerindian

  19. Information Geometry Formalism for the Spatially Homogeneous Boltzmann Equation

    NASA Astrophysics Data System (ADS)

    Lods, Bertrand; Pistone, Giovanni

    2015-06-01

    Information Geometry generalizes to infinite dimension by modeling the tangent space of the relevant manifold of probability densities with exponential Orlicz spaces. We review here several properties of the exponential manifold on a suitable set $\\mathcal E$ of mutually absolutely continuous densities. We study in particular the fine properties of the Kullback-Liebler divergence in this context. We also show that this setting is well-suited for the study of the spatially homogeneous Boltzmann equation if $\\mathcal E$ is a set of positive densities with finite relative entropy with respect to the Maxwell density. More precisely, we analyse the Boltzmann operator in the geometric setting from the point of its Maxwell's weak form as a composition of elementary operations in the exponential manifold, namely tensor product, conditioning, marginalization and we prove in a geometric way the basic facts i.e., the H-theorem. We also illustrate the robustness of our method by discussing, besides the Kullback-Leibler divergence, also the property of Hyv\\"arinen divergence. This requires to generalise our approach to Orlicz-Sobolev spaces to include derivatives.%

  20. Fluoxetine Restores Spatial Learning but Not Accelerated Forgetting in Mesial Temporal Lobe Epilepsy

    ERIC Educational Resources Information Center

    Barkas, Lisa; Redhead, Edward; Taylor, Matthew; Shtaya, Anan; Hamilton, Derek A.; Gray, William P.

    2012-01-01

    Learning and memory dysfunction is the most common neuropsychological effect of mesial temporal lobe epilepsy, and because the underlying neurobiology is poorly understood, there are no pharmacological strategies to help restore memory function in these patients. We have demonstrated impairments in the acquisition of an allocentric spatial task,…

  1. Switching from Reaching to Navigation: Differential Cognitive Strategies for Spatial Memory in Children and Adults

    ERIC Educational Resources Information Center

    Belmonti, Vittorio; Cioni, Giovanni; Berthoz, Alain

    2015-01-01

    Navigational and reaching spaces are known to involve different cognitive strategies and brain networks, whose development in humans is still debated. In fact, high-level spatial processing, including allocentric location encoding, is already available to very young children, but navigational strategies are not mature until late childhood. The…

  2. Virtual Reality Body Swapping: A Tool for Modifying the Allocentric Memory of the Body.

    PubMed

    Serino, Silvia; Pedroli, Elisa; Keizer, Anouk; Triberti, Stefano; Dakanalis, Antonios; Pallavicini, Federica; Chirico, Alice; Riva, Giuseppe

    2016-02-01

    An increasing amount of evidence has shown that embodiment of a virtual body via visuo-tactile stimulation can lead to an altered perception of body and object size. The current study aimed to investigate whether virtual reality (VR) body swapping can be an effective tool for modifying the enduring memory of the body. The experimental sample included 21 female participants who were asked to estimate the width and circumference of different body parts before any kind of stimulation and after two types of body swapping illusions ("synchronous visuo-tactile stimulation" and "asynchronous visuo-tactile stimulation"). Findings revealed that after participants embodied a virtual body with a skinny belly (independently of the type of visuo-tactile stimulation), there was an update of the stored representation of the body: participants reported a decrease in the ratio between estimated and actual body measures for most of the body parts considered. Based on the Allocentric Lock Theory, these findings provide first evidence that VR body swapping is able to induce a change in the memory of the body. This knowledge may be potentially useful for patients suffering from eating and weight disorders. PMID:26506136

  3. A study on heterogeneous distributed spatial information platform based on semantic Web services

    NASA Astrophysics Data System (ADS)

    Peng, Shuang-yun; Yang, Kun; Xu, Quan-li; Huang, Bang-mei

    2008-10-01

    With the development of Semantic Web technology, the spatial information service based on ontology is an effective way for sharing and interoperation of heterogeneous information resources in the distributed network environment. This paper discusses spatial information sharing and interoperability in the Semantic Web Services architecture. Through using Ontology record spatial information in sharing knowledge system, explicit and formalization expresses the default and the concealment semantic information. It provides the prerequisite for spatial information sharing and interoperability; Through Semantic Web Services technology parses Ontology and intelligent buildings services under network environment, form a network of services. In order to realize the practical applications of spatial information sharing and interoperation in different brunches of CDC system, a prototype system for HIV/AIDS information sharing based on geo-ontology has also been developed by using the methods described above.

  4. Implementing an SIG based platform of application and service for city spatial information in Shanghai

    NASA Astrophysics Data System (ADS)

    Yu, Bailang; Wu, Jianping

    2006-10-01

    Spatial Information Grid (SIG) is an infrastructure that has the ability to provide the services for spatial information according to users' needs by means of collecting, sharing, organizing and processing the massive distributed spatial information resources. This paper presents the architecture, technologies and implementation of the Shanghai City Spatial Information Application and Service System, a SIG based platform, which is an integrated platform that serves for administration, planning, construction and development of the city. In the System, there are ten categories of spatial information resources, including city planning, land-use, real estate, river system, transportation, municipal facility construction, environment protection, sanitation, urban afforestation and basic geographic information data. In addition, spatial information processing services are offered as a means of GIS Web Services. The resources and services are all distributed in different web-based nodes. A single database is created to store the metadata of all the spatial information. A portal site is published as the main user interface of the System. There are three main functions in the portal site. First, users can search the metadata and consequently acquire the distributed data by using the searching results. Second, some spatial processing web applications that developed with GIS Web Services, such as file format conversion, spatial coordinate transfer, cartographic generalization and spatial analysis etc, are offered to use. Third, GIS Web Services currently available in the System can be searched and new ones can be registered. The System has been working efficiently in Shanghai Government Network since 2005.

  5. The posterior parietal cortex and long-term memory representation of spatial information

    PubMed Central

    Kesner, Raymond P.

    2009-01-01

    The hypothesis to be explored in this chapter is based on the assumption that the posterior parietal cortex (PPC) is directly involved in representing a subset of the spatial features associated with spatial information processing and plays an important role in perceptual memory as well as long-term memory encoding, consolidation, and retrieval of spatial information. After presentation of the anatomical location of the PPC in rats, the nature of PPC representation based on single spatial features, binding of visual features associated with visual spatial attention, binding of object-place associations associated with acquisition and storage of associations where one of the elements is a spatial component, and binding of ideothetic and allothetic information in long-term memory is discussed. Additional evidence for a PPC role in mediation of spatial information in long-term storage is offered. Finally, the relationship between the PPC and the hippocampus from a systems and dynamic point view is presented. PMID:18835456

  6. Inability to acquire spatial information and deploy spatial search strategies in mice with lesions in dorsomedial striatum.

    PubMed

    Pooters, Tine; Gantois, Ilse; Vermaercke, Ben; D'Hooge, Rudi

    2016-02-01

    Dorsal striatum has been shown to contribute to spatial learning and memory, but the role of striatal subregions in this important aspect of cognitive functioning remains unclear. Moreover, the spatial-cognitive mechanisms that underlie the involvement of these regions in spatial navigation have scarcely been studied. We therefore compared spatial learning and memory performance in mice with lesions in dorsomedial (DMS) and dorsolateral striatum (DLS) using the hidden-platform version of the Morris water maze (MWM) task. Compared to sham-operated controls, animals with DMS damage were impaired during MWM acquisition training. These mice displayed delayed spatial learning, increased thigmotaxis, and increased search distance to the platform, in the absence of major motor dysfunction, working memory defects or changes in anxiety or exploration. They failed to show a preference for the target quadrant during probe trials, which further indicates that spatial reference memory was impaired in these animals. Search strategy analysis moreover demonstrated that DMS-lesioned mice were unable to deploy cognitively advanced spatial search strategies. Conversely, MWM performance was barely affected in animals with lesions in DLS. In conclusion, our results indicate that DMS and DLS display differential functional involvement in spatial learning and memory. Our results show that DMS, but not DLS, is crucial for the ability of mice to acquire spatial information and their subsequent deployment of spatial search strategies. These data clearly identify DMS as a crucial brain structure for spatial learning and memory, which could explain the occurrence of neurocognitive impairments in brain disorders that affect the dorsal striatum. PMID:26548360

  7. When do objects become landmarks? A VR study of the effect of task relevance on spatial memory.

    PubMed

    Han, Xue; Byrne, Patrick; Kahana, Michael; Becker, Suzanna

    2012-01-01

    We investigated how objects come to serve as landmarks in spatial memory, and more specifically how they form part of an allocentric cognitive map. Participants performing a virtual driving task incidentally learned the layout of a virtual town and locations of objects in that town. They were subsequently tested on their spatial and recognition memory for the objects. To assess whether the objects were encoded allocentrically we examined pointing consistency across tested viewpoints. In three experiments, we found that spatial memory for objects at navigationally relevant locations was more consistent across tested viewpoints, particularly when participants had more limited experience of the environment. When participants' attention was focused on the appearance of objects, the navigational relevance effect was eliminated, whereas when their attention was focused on objects' locations, this effect was enhanced, supporting the hypothesis that when objects are processed in the service of navigation, rather than merely being viewed as objects, they engage qualitatively distinct attentional systems and are incorporated into an allocentric spatial representation. The results are consistent with evidence from the neuroimaging literature that when objects are relevant to navigation, they not only engage the ventral "object processing stream", but also the dorsal stream and medial temporal lobe memory system classically associated with allocentric spatial memory. PMID:22586455

  8. Spatial memory deficit across aging: current insights of the role of 5-HT7 receptors

    PubMed Central

    Beaudet, Gregory; Bouet, Valentine; Jozet-Alves, Christelle; Schumann-Bard, Pascale; Dauphin, François; Paizanis, Eleni; Boulouard, Michel; Freret, Thomas

    2015-01-01

    Elderly persons often face biological, psychological or social changes over time that may cause discomfort or morbidity. While some cognitive domains remain stable over time, others undergo a decline. Spatial navigation is a complex cognitive function essential for independence, safety and quality of life. While egocentric (body-centered) navigation is quite preserved during aging, allocentric (externally-centered) navigation—based on a cognitive map using distant landmarks—declines with age. Recent preclinical studies showed that serotonergic 5-HT7 receptors are localized in brain regions associated with allocentric spatial navigation processing. Behavioral assessments with pharmacological or genetic tools have confirmed the role of 5-HT7 receptors in allocentric navigation. Moreover, few data suggested a selective age-related decrease in the expression of 5-HT7 receptors in pivotal brain structures implicated in allocentric navigation such as the hippocampal CA3 region. We aim to provide a short overview of the potential role of 5-HT7 receptors in spatial navigation, and to argue for their interests as therapeutic targets against age-related cognitive decline. PMID:25642173

  9. Geographical epidemiology, spatial analysis and geographical information systems: a multidisciplinary glossary

    PubMed Central

    Rezaeian, Mohsen; Dunn, Graham; Leger, Selwyn St; Appleby, Louis

    2007-01-01

    We provide a relatively non‐technical glossary of terms and a description of the tools used in spatial or geographical epidemiology and associated geographical information systems. Statistical topics included cover adjustment and standardisation to allow for demographic and other background differences, data structures, data smoothing, spatial autocorrelation and spatial regression. We also discuss the rationale for geographical epidemiology and specific techniques such as disease clustering, disease mapping, ecological analyses, geographical information systems and global positioning systems. PMID:17234866

  10. Asymmetric Learning Transfer between Imagined Viewer- and Object-Rotations: Evidence of a Hierarchical Organization of Spatial Reference Frames

    ERIC Educational Resources Information Center

    Pellizzer, Giuseppe; Ba, Maryse Badan; Zanello, Adriano; Merlo, Marco C. G.

    2009-01-01

    Neural resources subserving spatial processing in either egocentric or allocentric reference frames are, at least partly, dissociated. However, it is unclear whether these two types of representations are independent or whether they interact. We investigated this question using a learning transfer paradigm. The experiment and material were…

  11. A SPATIALLY REALISTIC MODEL FOR INFORMING FOREST MANAGEMENT DECISIONS

    EPA Science Inventory

    Spatially realistic population models (SRPMs) address a fundamental
    problem commonly confronted by wildlife managers - predicting the
    effects of landscape-scale habitat management on an animal population.
    SRPMs typically consist of three submodels: (1) a habitat submodel...

  12. Multiple reference frames in haptic spatial processing

    NASA Astrophysics Data System (ADS)

    Volčič, R.

    2008-08-01

    The present thesis focused on haptic spatial processing. In particular, our interest was directed to the perception of spatial relations with the main focus on the perception of orientation. To this end, we studied haptic perception in different tasks, either in isolation or in combination with vision. The parallelity task, where participants have to match the orientations of two spatially separated bars, was used in its two-dimensional and three-dimensional versions in Chapter 2 and Chapter 3, respectively. The influence of non-informative vision and visual interference on performance in the parallelity task was studied in Chapter 4. A different task, the mental rotation task, was introduced in a purely haptic study in Chapter 5 and in a visuo-haptic cross-modal study in Chapter 6. The interaction of multiple reference frames and their influence on haptic spatial processing were the common denominators of these studies. In this thesis we approached the problems of which reference frames play the major role in haptic spatial processing and how the relative roles of distinct reference frames change depending on the available information and the constraints imposed by different tasks. We found that the influence of a reference frame centered on the hand was the major cause of the deviations from veridicality observed in both the two-dimensional and three-dimensional studies. The results were described by a weighted average model, in which the hand-centered egocentric reference frame is supposed to have a biasing influence on the allocentric reference frame. Performance in haptic spatial processing has been shown to depend also on sources of information or processing that are not strictly connected to the task at hand. When non-informative vision was provided, a beneficial effect was observed in the haptic performance. This improvement was interpreted as a shift from the egocentric to the allocentric reference frame. Moreover, interfering visual information presented

  13. Detecting structural information of scatterers using spatial frequency domain imaging.

    PubMed

    Bodenschatz, Nico; Krauter, Philipp; Nothelfer, Steffen; Foschum, Florian; Bergmann, Florian; Liemert, André; Kienle, Alwin

    2015-11-01

    We demonstrate optical phantom experiments on the phase function parameter γ using spatial frequency domain imaging. The incorporation of two different types of scattering particles allows for control of the optical phantoms’ microscopic scattering properties. By laterally structuring areas with either TiO2 or Al2O3 scattering particles, we were able to obtain almost pure subdiffusive scattering contrast in a single optical phantom. Optical parameter mapping was then achieved using an analytical radiative transfer model revealing the microscopic structural contrast on a macroscopic field of view. As part of our study, we explain several correction and referencing techniques for high spatial frequency analysis and experimentally study the sampling depth of the subdiffusive parameter γ. PMID:26590206

  14. Age-related effects on spatial memory across viewpoint changes relative to different reference frames.

    PubMed

    Montefinese, Maria; Sulpizio, Valentina; Galati, Gaspare; Committeri, Giorgia

    2015-07-01

    Remembering object positions across different views is a fundamental competence for acting and moving appropriately in a large-scale space. Behavioural and neurological changes in elderly subjects suggest that the spatial representations of the environment might decline compared to young participants. However, no data are available on the use of different reference frames within topographical space in aging. Here we investigated the use of allocentric and egocentric frames in aging, by asking young and older participants to encode the location of a target in a virtual room relative either to stable features of the room (allocentric environment-based frame), or to an unstable objects set (allocentric objects-based frame), or to the viewer's viewpoint (egocentric frame). After a viewpoint change of 0° (absent), 45° (small) or 135° (large), participants judged whether the target was in the same spatial position as before relative to one of the three frames. Results revealed a different susceptibility to viewpoint changes in older than young participants. Importantly, we detected a worst performance, in terms of reaction times, for older than young participants in the allocentric frames. The deficit was more marked for the environment-based frame, for which a lower sensitivity was revealed as well as a worst performance even when no viewpoint change occurred. Our data provide new evidence of a greater vulnerability of the allocentric, in particular environment-based, spatial coding with aging, in line with the retrogenesis theory according to which cognitive changes in aging reverse the sequence of acquisition in mental development. PMID:25037856

  15. THE IMPORTANCE OF SPATIAL ACCURACY FOR CHEMICAL INFORMATION MANAGEMENT

    EPA Science Inventory

    Information about chemicals can be critical to making timely decisions. The results of these decisions may not be realized for many years. In order to increase the value of chemical information and to create and utilize meaningful environmental models, the Environmental Prote...

  16. Spatial navigation impairment is proportional to right hippocampal volume

    PubMed Central

    Nedelska, Zuzana; Andel, Ross; Laczó, Jan; Vlcek, Kamil; Horinek, Daniel; Lisy, Jiri; Sheardova, Katerina; Bureš, Jan; Hort, Jakub

    2012-01-01

    Cognitive deficits in older adults attributable to Alzheimer's disease (AD) pathology are featured early on by hippocampal impairment. Among these individuals, deterioration in spatial navigation, manifested by poor hippocampus-dependent allocentric navigation, may occur well before the clinical onset of dementia. Our aim was to determine whether allocentric spatial navigation impairment would be proportional to right hippocampal volume loss irrespective of general brain atrophy. We also contrasted the respective spatial navigation scores of the real-space human Morris water maze with its corresponding 2D computer version. We included 42 cognitively impaired patients with either amnestic mild cognitive impairment (n = 23) or mild and moderate AD (n = 19), and 14 cognitively intact older controls. All participants underwent 1.5T MRI brain scanning with subsequent automatic measurement of the total brain and hippocampal (right and left) volumes. Allocentric spatial navigation was tested in the real-space version of the human Morris water maze and in its corresponding computer version. Participants used two navigational cues to locate an invisible goal independent of the start position. We found that smaller right hippocampal volume was associated with poorer navigation performance in both the real-space (β = −0.62, P < 0.001) and virtual (β = −0.43, P = 0.026) versions, controlling for demographic variables, total brain and left hippocampal volumes. In subsequent analyses, the results were significant in cognitively impaired (P ≤ 0.05) but not in cognitively healthy (P > 0.59) subjects. The respective real-space and virtual scores strongly correlated with each other. Our findings indicate that the right hippocampus plays a critical role in allocentric navigation, particularly when cognitive impairment is present. PMID:22308496

  17. [An improved N-FINDR endmember extraction algorithm based on manifold learning and spatial information].

    PubMed

    Tang, Xiao-yan; Gao, Kun; Ni, Guo-qiang; Zhu, Zhen-yu; Cheng, Hao-bo

    2013-09-01

    An improved N-FINDR endmember extraction algorithm by combining manifold learning and spatial information is presented under nonlinear mixing assumptions. Firstly, adaptive local tangent space alignment is adapted to seek potential intrinsic low-dimensional structures of hyperspectral high-diemensional data and reduce original data into a low-dimensional space. Secondly, spatial preprocessing is used by enhancing each pixel vector in spatially homogeneous areas, according to the continuity of spatial distribution of the materials. Finally, endmembers are extracted by looking for the largest simplex volume. The proposed method can increase the precision of endmember extraction by solving the nonlinearity of hyperspectral data and taking advantage of spatial information. Experimental results on simulated and real hyperspectral data demonstrate that the proposed approach outperformed the geodesic simplex volume maximization (GSVM), vertex component analysis (VCA) and spatial preprocessing N-FINDR method (SPPNFINDR). PMID:24369664

  18. A new distributed computing model of mobile spatial information service grid based on mobile agent

    NASA Astrophysics Data System (ADS)

    Tian, Gen; Liu, Miao-long

    2009-10-01

    A new distributed computing model of mobile spatial information service is studied based on grid computing environment. Key technologies are presented in the model, including mobile agent (MA) distributed computing, grid computing, spatial data model, location based service (LBS), global positioning system (GPS), code division multiple access (CDMA), transfer control protocol/internet protocol (TCP/IP), and user datagram protocol (UDP). In order to deal with the narrow bandwidth and instability of the wireless internet, distributed organization of tremendous spatial data, limited processing speed and low memory of mobile devices, a new mobile agent based mobile spatial information service grid (MSISG) architecture is further proposed that has good load balance, high processing efficiency, less network communication and thus suitable for mobile distributed computing environment. It can provide applications of spatial information distributed computing and mobile service. The theories and technologies architecture of MSISG are built originally from the base, including spatial information mobile agent model, distributed grid geographic information system (GIS) server model, mobile agent server model and mobile GIS client model. An application system for MSISG is therefore developed authorship by visual c++ and embedded visual c++. A field test is carried out through this system in Shanghai, and the results show that the proposed model and methods are feasible and adaptable for mobile spatial information service.

  19. A new distributed computing model of mobile spatial information service grid based on mobile agent

    NASA Astrophysics Data System (ADS)

    Tian, Gen; Liu, Miao-long

    2008-10-01

    A new distributed computing model of mobile spatial information service is studied based on grid computing environment. Key technologies are presented in the model, including mobile agent (MA) distributed computing, grid computing, spatial data model, location based service (LBS), global positioning system (GPS), code division multiple access (CDMA), transfer control protocol/internet protocol (TCP/IP), and user datagram protocol (UDP). In order to deal with the narrow bandwidth and instability of the wireless internet, distributed organization of tremendous spatial data, limited processing speed and low memory of mobile devices, a new mobile agent based mobile spatial information service grid (MSISG) architecture is further proposed that has good load balance, high processing efficiency, less network communication and thus suitable for mobile distributed computing environment. It can provide applications of spatial information distributed computing and mobile service. The theories and technologies architecture of MSISG are built originally from the base, including spatial information mobile agent model, distributed grid geographic information system (GIS) server model, mobile agent server model and mobile GIS client model. An application system for MSISG is therefore developed authorship by visual c++ and embedded visual c++. A field test is carried out through this system in Shanghai, and the results show that the proposed model and methods are feasible and adaptable for mobile spatial information service.

  20. Mapping invasive weeds and their control with spatial information technologies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We discuss applications of airborne multispectral digital imaging systems, imaging processing techniques, global positioning systems (GPS), and geographic information systems (GIS) for mapping the invasive weeds giant salvinia (Salvinia molesta) and Brazilian pepper (Schinus terebinthifolius) and fo...

  1. Information analysis of a spatial database for ecological land classification

    NASA Technical Reports Server (NTRS)

    Davis, Frank W.; Dozier, Jeff

    1990-01-01

    An ecological land classification was developed for a complex region in southern California using geographic information system techniques of map overlay and contingency table analysis. Land classes were identified by mutual information analysis of vegetation pattern in relation to other mapped environmental variables. The analysis was weakened by map errors, especially errors in the digital elevation data. Nevertheless, the resulting land classification was ecologically reasonable and performed well when tested with higher quality data from the region.

  2. The Implicit Use of Spatial Information Develops Later for Crossmodal than for Intramodal Temporal Processing

    ERIC Educational Resources Information Center

    Roder, Brigitte; Pagel, Birthe; Heed, Tobias

    2013-01-01

    The integrated use of spatial and temporal information seems to support the separation of two sensory streams. The present study tested whether this facilitation depends on the encoding of sensory stimuli in externally anchored spatial coordinate systems. Fifty-nine children between 5 and 12 years as well as 12 young adults performed a crossmodal…

  3. Influences of Training and Strategical Information Processing Style on Spatial Performance in Apparel Design

    ERIC Educational Resources Information Center

    Gitimu, Priscilla N.; Workman, Jane E.; Anderson, Marcia A.

    2005-01-01

    The study investigated how performance on a spatial task in apparel design was influenced by training and strategical information processing style. The sample consisted of 278 undergraduate apparel design students from six universities in the U.S. Instruments used to collect data were the Apparel Spatial Visualization Test (ASVT) and the…

  4. Integrating Information: A Meta-Analysis of the Spatial Contiguity and Temporal Contiguity Effects

    ERIC Educational Resources Information Center

    Ginns, Paul

    2006-01-01

    This article reviews research on the spatial contiguity and temporal contiguity effects. Research on these instructional design effects has focussed on the instructional benefits for novices of reducing split attention between spatially or temporally disparate but related elements of information. Meta-analytic techniques were applied to 50…

  5. Advanced Extraction of Spatial Information from High Resolution Satellite Data

    NASA Astrophysics Data System (ADS)

    Pour, T.; Burian, J.; Miřijovský, J.

    2016-06-01

    In this paper authors processed five satellite image of five different Middle-European cities taken by five different sensors. The aim of the paper was to find methods and approaches leading to evaluation and spatial data extraction from areas of interest. For this reason, data were firstly pre-processed using image fusion, mosaicking and segmentation processes. Results going into the next step were two polygon layers; first one representing single objects and the second one representing city blocks. In the second step, polygon layers were classified and exported into Esri shapefile format. Classification was partly hierarchical expert based and partly based on the tool SEaTH used for separability distinction and thresholding. Final results along with visual previews were attached to the original thesis. Results are evaluated visually and statistically in the last part of the paper. In the discussion author described difficulties of working with data of large size, taken by different sensors and different also thematically.

  6. Spatial information in large-scale neural recordings

    PubMed Central

    Cybulski, Thaddeus R.; Glaser, Joshua I.; Marblestone, Adam H.; Zamft, Bradley M.; Boyden, Edward S.; Church, George M.; Kording, Konrad P.

    2015-01-01

    To record from a given neuron, a recording technology must be able to separate the activity of that neuron from the activity of its neighbors. Here, we develop a Fisher information based framework to determine the conditions under which this is feasible for a given technology. This framework combines measurable point spread functions with measurable noise distributions to produce theoretical bounds on the precision with which a recording technology can localize neural activities. If there is sufficient information to uniquely localize neural activities, then a technology will, from an information theoretic perspective, be able to record from these neurons. We (1) describe this framework, and (2) demonstrate its application in model experiments. This method generalizes to many recording devices that resolve objects in space and should be useful in the design of next-generation scalable neural recording systems. PMID:25653613

  7. Change of spatial information under rescaling: A case study using multi-resolution image series

    NASA Astrophysics Data System (ADS)

    Chen, Weirong; Henebry, Geoffrey M.

    Spatial structure in imagery depends on a complicated interaction between the observational regime and the types and arrangements of entities within the scene that the image portrays. Although block averaging of pixels has commonly been used to simulate coarser resolution imagery, relatively little attention has been focused on the effects of simple rescaling on spatial structure and the explanation and a possible solution to the problem. Yet, if there are significant differences in spatial variance between rescaled and observed images, it may affect the reliability of retrieved biogeophysical quantities. To investigate these issues, a nested series of high spatial resolution digital imagery was collected at a research site in eastern Nebraska in 2001. An airborne Kodak DCS420IR camera acquired imagery at three altitudes, yielding nominal spatial resolutions ranging from 0.187 m to 1 m. The red and near infrared (NIR) bands of the co-registered image series were normalized using pseudo-invariant features, and the normalized difference vegetation index (NDVI) was calculated. Plots of grain sorghum planted in orthogonal crop row orientations were extracted from the image series. The finest spatial resolution data were then rescaled by averaging blocks of pixels to produce a rescaled image series that closely matched the spatial resolution of the observed image series. Spatial structures of the observed and rescaled image series were characterized using semivariogram analysis. Results for NDVI and its component bands show, as expected, that decreasing spatial resolution leads to decreasing spatial variability and increasing spatial dependence. However, compared to the observed data, the rescaled images contain more persistent spatial structure that exhibits limited variation in both spatial dependence and spatial heterogeneity. Rescaling via simple block averaging fails to consider the effect of scene object shape and extent on spatial information. As the features

  8. Part-Set Cuing Facilitation for Spatial Information

    ERIC Educational Resources Information Center

    Cole, Sydni M.; Reysen, Matthew B.; Kelley, Matthew R.

    2013-01-01

    Part-set cuing "inhibition" refers to the counterintuitive finding that hints--specifically, part of the set of to-be-remembered information--often impair memory performance in free recall tasks. Although inhibition is the most commonly reported result, part-set cuing "facilitation" has been shown with serial order tasks. The…

  9. Seeking Information Online: The Influence of Menu Type, Navigation Path Complexity and Spatial Ability on Information Gathering Tasks

    ERIC Educational Resources Information Center

    Puerta Melguizo, Mari Carmen; Vidya, Uti; van Oostendorp, Herre

    2012-01-01

    We studied the effects of menu type, navigation path complexity and spatial ability on information retrieval performance and web disorientation or lostness. Two innovative aspects were included: (a) navigation path relevance and (b) information gathering tasks. As expected we found that, when measuring aspects directly related to navigation…

  10. Development of Climate Change Adaptation Platform using Spatial Information

    NASA Astrophysics Data System (ADS)

    Lee, J.; Oh, K. Y.; Lee, M. J.; Han, W. J.

    2014-12-01

    Climate change adaptation has attracted growing attention with the recent extreme weather conditions that affect people around the world. More and more countries, including the Republic of Korea, have begun to hatch adaptation plan to resolve these matters of great concern. They all, meanwhile, have mentioned that it should come first to integrate climate information in all analysed areas. That's because climate information is not independently made through one source; that is to say, the climate information is connected one another in a complicated way. That is the reason why we have to promote integrated climate change adaptation platform before setting up climate change adaptation plan. Therefore, the large-scaled project has been actively launched and worked on. To date, we researched 620 literatures and interviewed 51 government organizations. Based on the results of the researches and interviews, we obtained 2,725 impacts about vulnerability assessment information such as Monitoring and Forecasting, Health, Disaster, Agriculture, Forest, Water Management, Ecosystem, Ocean/Fisheries, Industry/Energy. Among 2,725 impacts, 995 impacts are made into a database until now. This database is made up 3 sub categories like Climate-Exposure, Sensitivity, Adaptive capacity, presented by IPCC. Based on the constructed database, vulnerability assessments were carried out in order to evaluate climate change capacity of local governments all over the country. These assessments were conducted by using web-based vulnerability assessment tool which was newly developed through this project. These results have shown that, metropolitan areas like Seoul, Pusan, Inchon, and so on have high risks more than twice than rural areas. Acknowledgements: The authors appreciate the support that this study has received from "Development of integrated model for climate change impact and vulnerability assessment and strengthening the framework for model implementation ", an initiative of the

  11. Use of Spatial Variance Information From Remote Sensing Imagery to Map Vegetation Foliage Density

    NASA Astrophysics Data System (ADS)

    Walthall, C. L.; Timlin, D.; Pachepsky, Y.; Dulaney, W.; Daughtry, C.

    2002-12-01

    Maps of foliage density expressed as leaf area index (LAI) are used for natural resources inventories, land surface-atmosphere interaction modeling, and hydrologic modeling. Remote sensing imagery can be used to produce these maps by relating spectral vegetation indexes (SVIs) to LAI calibration samples acquired at selected locations on the surface. This approach traditionally uses ordinary least squares (OLS) relationships between the surface measurements and the SVIs, and does not fully take advantage of the spatial information content of the imagery. Spatial information inherent in a semivariogram of the imagery may provide additional information for mapping LAI patterns. This is demonstrated using a spatially dense sample of corn LAI and calibrated airborne imagery. An LAI map is produced by interpolating surface measurements with a semivariogram from the imagery. The resulting LAI map captures the main spatial features of a LAI map produced by interpolating the surface LAI data with its semivariogram. The image semivariogram approach also provides a product that has less noise characteristic of OLS-based remote sensing methods. The use of the image semivariogram with the surface LAI calibration samples suggests that the spatial domain information can complement spectral information for improving LAI maps especially at high spatial resolution where OLS methods may not perform well.

  12. Analyzing existing conventional soil information sources to be incorporated in thematic Spatial Data Infrastructures

    NASA Astrophysics Data System (ADS)

    Pascual-Aguilar, J. A.; Rubio, J. L.; Domínguez, J.; Andreu, V.

    2012-04-01

    New information technologies give the possibility of widespread dissemination of spatial information to different geographical scales from continental to local by means of Spatial Data Infrastructures. Also administrative awareness on the need for open access information services has allowed the citizens access to this spatial information through development of legal documents, such as the INSPIRE Directive of the European Union, adapted by national laws as in the case of Spain. The translation of the general criteria of generic Spatial Data Infrastructures (SDI) to thematic ones is a crucial point for the progress of these instruments as large tool for the dissemination of information. In such case, it must be added to the intrinsic criteria of digital information, such as the harmonization information and the disclosure of metadata, the own environmental information characteristics and the techniques employed in obtaining it. In the case of inventories and mapping of soils, existing information obtained by traditional means, prior to the digital technologies, is considered to be a source of valid information, as well as unique, for the development of thematic SDI. In this work, an evaluation of existing and accessible information that constitutes the basis for building a thematic SDI of soils in Spain is undertaken. This information framework has common features to other European Union states. From a set of more than 1,500 publications corresponding to the national territory of Spain, the study was carried out in those documents (94) found for five autonomous regions of northern Iberian Peninsula (Asturias, Cantabria, Basque Country, Navarra and La Rioja). The analysis was performed taking into account the criteria of soil mapping and inventories. The results obtained show a wide variation in almost all the criteria: geographic representation (projections, scales) and geo-referencing the location of the profiles, map location of profiles integrated with edaphic

  13. Human Topological Task Adapted for Rats: Spatial Information Processes of the Parietal Cortex

    PubMed Central

    Goodrich-Hunsaker, Naomi J.; Howard, Brian P.; Hunsaker, Michael R.; Kesner, Raymond P.

    2008-01-01

    Human research has shown that lesions of the parietal cortex disrupt spatial information processing, specifically topological information. Similar findings have been found in nonhumans. It has been difficult to determine homologies between human and non-human mnemonic mechanisms for spatial information processing because methodologies and neuropathology differ. The first objective of the present study was to adapt a previously established human task for rats. The second objective was to better characterize the role of parietal cortex (PC) and dorsal hippocampus (dHPC) for topological spatial information processing. Rats had to distinguish whether a ball inside a ring or a ball outside a ring was the correct, rewarded object. After rats reached criterion on the task (>95%) they were randomly assigned to a lesion group (control, PC, dHPC). Animals were then re-tested. Post-surgery data show that controls were 94% correct on average, dHPC rats were 89% correct on average, and PC rats were 56% correct on average. The results from the present study suggest that the parietal cortex, but not the dHPC processes topological spatial information. The present data are the first to support comparable topological spatial information processes of the parietal cortex in humans and rats. PMID:18571941

  14. Phase conjugation of mode scrambled optical beams Application to spatial recovery and interbeam temporal information exchange

    NASA Astrophysics Data System (ADS)

    Yahalom, Ram; Kyuma, Kazuo; Yariv, Amnon

    1987-03-01

    Coupling of temporal information between two beams is demonstrated using a combination of a multimode fiber and a photorefractive passive phase conjugation mirror. It is shown that the polarization and spatial properties are fully recovered but temporal information is exchanged. The theoretical explanation for these phenomena and possible applications are discussed.

  15. The brain uses efference copy information to optimise spatial memory.

    PubMed

    Gonzalez, C C; Burke, M R

    2013-01-01

    Does a motor response to a target improve the subsequent recall of the target position or can we simply use peripheral position information to guide an accurate response? We suggest that a motor plan of the hand can be enhanced with actual motor and efference copy feedback (GoGo trials), which is absent in the passive observation of a stimulus (NoGo trials). To investigate this effect during eye and hand coordination movements, we presented stimuli in two formats (memory guided or visually guided) under three modality conditions (eyes only, hands only (with eyes fixated), or eyes and hand together). We found that during coordinated movements, both the eye and hand response times were facilitated when efference feedback of the movement was provided. Furthermore, both eye and hand movements to remembered locations were significantly more accurate in the GoGo than in the NoGo trial types. These results reveal that an efference copy of a motor plan enhances memory for a location that is not only observed in eye movements, but also translated downstream into a hand movement. These results have significant implications on how we plan, code and guide behavioural responses, and how we can optimise accuracy and timing to a given target. PMID:23073714

  16. A spatial information crawler for OpenGIS WFS

    NASA Astrophysics Data System (ADS)

    Jiang, Jun; Yang, Chong-jun; Ren, Ying-chao

    2008-10-01

    The growth of the internet makes it non-trivial to search for the accuracy information efficiently. Topical crawler, which is aiming at a certain area, attracts more and more intention now because it can help people to find out what they need. Furthermore, with the OpenGIS WFS (Web Feature Service) Specification developed by OGC (Open GIS Consortium), much more geospatial data providers adopt this protocol to publish their data on the internet. In this case, a crawler which is aiming at the WFS servers can help people to find the geospatial data from WFS servers. In this paper, we propose a prototype system of a WFS crawler based on the OpenGIS WFS Specification. The crawler architecture, working principles, and detailed function of each component are introduced. This crawler is capable of discovering WFS servers dynamically, saving and updating the service contents of the servers. The data collect by the crawler can be supported to a geospatial data search engine as its data source.

  17. Spatial Collective Intelligence? credibility, accuracy, and Volunteered Geographic Information

    PubMed Central

    Spielman, Seth E.

    2014-01-01

    Collective intelligence is the idea that under the right circumstances collections of individuals are smarter than even the smartest individuals in the group (Suroweiki 2004), that is a group has an “intelligence” that is independent of the intelligence of its members. The ideology of collective intelligence undergirds much of the enthusiasm about the use of “volunteered” or crowdsourced geographic information. Literature from a variety of fields makes clear that not all groups possess collective intelligence, this paper identifies four pre-conditions for the emergence of collective intelligence and then examine the extent to which collectively generated mapping systems satisfy these conditions. However, the “intelligence” collectively generated maps is hard to assess because there are two difficult to reconcile perspectives on map quality- the credibility perspective and the accuracy perspective. Much of the current literature on user generated maps focuses on assessing the quality of individual contributions. However, because user generated maps are complex social systems and because the quality of a contribution is difficult to assess this strategy may not yield an “intelligent” end product. The existing literature on collective intelligence suggests that the structure of groups more important that the intelligence of group members. Applying this idea to user generated suggests that systems should be designed to foster conditions known to produce collective intelligence rather than privileging particular contributions/contributors. The paper concludes with some design recommendations and by considering the implications of collectively generated maps for both expert knowledge and traditional state sponsored mapping programs. PMID:25419184

  18. Role of gravitational versus egocentric cues for human spatial orientation.

    PubMed

    Bury, Nils; Bock, Otmar

    2016-04-01

    Our perception of the vertical depends on allocentric information about the visual surrounds, egocentric information about the own body axis and gravicentric information about the pull of gravity. Previous work has documented that some individuals rely strongly on allocentric information, while others do not, and the present work scrutinizes the existence of yet another dichotomy: We hypothesize that in the absence of allocentric cues, some individuals rely strongly on gravicentric information, while others do not. Twenty-four participants were tested at three angles of body pitch (0° = upright, -90° = supine, -110° = head down) after eliminating visual orientation cues. When asked to adjust a rotating tree '…such that the tree looks right,' nine persons set the tree consistently parallel to gravity, eight consistently parallel to their longitudinal axis and seven switched between these two references; responses mid-between gravity and body axis were rare. The outcome was similar when tactile cues were masked by body vibration, as well as when participants were asked to adjust the tree '… such that leaves are at the top and roots are at the bottom'; the incidence of gravicentric responses increased with the instruction to set the tree '… such that leaves are at the top and roots are at the bottom in space, irrespective of your own position.' We conclude that the perceived vertical can be anchored in gravicentric or in egocentric space, depending on instructions and individual preference. PMID:26706040

  19. A Left Cerebral Hemisphere's Superiority in Processing Spatial-Categorical Information in a Non-Verbal Semantic Format

    ERIC Educational Resources Information Center

    Suegami, Takashi; Laeng, Bruno

    2013-01-01

    It has been shown that the left and right cerebral hemispheres (LH and RH) respectively process qualitative or "categorical" spatial relations and metric or "coordinate" spatial relations. However, categorical spatial information could be thought as divided into two types: semantically-coded and visuospatially-coded categorical information. We…

  20. A generic spatial-stochastic framework for quantifying noisy information flow in multicellular systems

    NASA Astrophysics Data System (ADS)

    Sokolowski, Thomas; Tkačik, Gašper

    Spatio-temporal protein signals play a crucial role in communicating information within and between cells. However, their ability to convey signals robustly is hampered by noise in gene regulation and biochemical transport, occuring at low copy numbers. While we increasingly understand distinct strategies of biochemical noise control, it remains unclear how nature orchestrates them to maximize information flow. Our recent work extends our information-theoretic framework for gene regulation to an explicitly spatial setting. We constructed a stochastic model enabling fast calculation of local means and variances in a spatially coupled gene regulatory system, which we use for rigorous quantification of information flow in an ensemble of units sensing a spatially distributed input and exchanging information via diffusion. By applying our framework to the paradigmatic Bcd-Hbk system in early fly development, we demonstrate that diffusive coupling can be of substantial benefit in encoding positional information, and uncover a novel optimal regulatory strategy relying on spatial coupling. Thanks to the generic methodology employed, our framework is universally applicable for realistic predictive modeling and data-driven inference of multicellular systems engaging in noisy communication. Institute of Science and Technology Austria, Am Campus 1, A-3400 Klosterneuburg, Austria.

  1. Spatial release from energetic and informational masking in a selective speech identification task.

    PubMed

    Ihlefeld, Antje; Shinn-Cunningham, Barbara

    2008-06-01

    A masker can reduce target intelligibility both by interfering with the target's peripheral representation ("energetic masking") and/or by causing more central interference ("informational masking"). Intelligibility generally improves with increasing spatial separation between two sources, an effect known as spatial release from masking (SRM). Here, SRM was measured using two concurrent sine-vocoded talkers. Target and masker were each composed of eight different narrowbands of speech (with little spectral overlap). The broadband target-to-masker energy ratio (TMR) was varied, and response errors were used to assess the relative importance of energetic and informational masking. Performance improved with increasing TMR. SRM occurred at all TMRs; however, the pattern of errors suggests that spatial separation affected performance differently, depending on the dominant type of masking. Detailed error analysis suggests that informational masking occurred due to failures in either across-time linkage of target segments (streaming) or top-down selection of the target. Specifically, differences in the spatial cues in target and masker improved streaming and target selection. In contrast, level differences helped listeners select the target, but had little influence on streaming. These results demonstrate that at least two mechanisms (differentially affected by spatial and level cues) influence informational masking. PMID:18537388

  2. [Mixed-Spectral Spatial Information Decomposition Model of Water Hyperspectral Inversion].

    PubMed

    Pan, Bang-long; Wang, Xian-hua; Zhu, Jin; Yi, Wei-ning; Fang, Ting-yong

    2015-03-01

    The effect of Mixed-hyperspectral in the water is difficult in quantitative remote sensing of water. Studies have shown that the only scalar spectrum information is difficult to solve the problem of complex mixed spectra of water. Besides the spectral information, spatial distribution of information is one of the obvious characteristics of the broad waters pollution, and can be used as a useful complement to the remote sensing information and facilitate water complex spectral unmixing. Taking Chaohu as an example, the paper applies the HJ-1A HSI hyperspectral data and the supplemental surface spectral measurement data to discuss the mixed spectra of lake water by spatial statistics and genetic algorithm theory. By using the spatial variogram of geostatistics to simulate the distribution difference of two adjacent pixels, the space-informational decomposition model of mixed spectral in lake water is established by co-kriging genetic algorithm, which is a improved algorithm applying the spatial variogram function of neighborhood pixel as the constraint of the objective function of the genetic algorithm. Finally, the model inversion results of suspended matter concentration are verified. Compared with the conventional spectral unmixing model, the results show the correlation coefficient of the predicted and measured value of suspended sediment concentration is 0.82, the root mean square error 9.25 mg x L(-1) by mixed spectral space information decomposition model, so the correlation coefficient is increased by 8.9%, the root mean square error reduced by 2.78 mg x L(-1), indicating that the model of suspended matter concentration has a strong predictive ability. Therefore, the effective combination of spatial and spectral information of water, can avoid inversion result distortion due to weak spectral signal of water color parameters, and large amount of calculation of information extraction because of the high spectral band numbers, and also provides an effective way

  3. Modeling of digital information optical encryption system with spatially incoherent illumination

    NASA Astrophysics Data System (ADS)

    Bondareva, Alyona P.; Cheremkhin, Pavel A.; Krasnov, Vitaly V.; Rodin, Vladislav G.; Starikov, Rostislav S.; Starikov, Sergey N.

    2015-10-01

    State of the art micromirror DMD spatial light modulators (SLM) offer unprecedented framerate up to 30000 frames per second. This, in conjunction with high speed digital camera, should allow to build high speed optical encryption system. Results of modeling of digital information optical encryption system with spatially incoherent illumination are presented. Input information is displayed with first SLM, encryption element - with second SLM. Factors taken into account are: resolution of SLMs and camera, holograms reconstruction noise, camera noise and signal sampling. Results of numerical simulation demonstrate high speed (several gigabytes per second), low bit error rate and high crypto-strength.

  4. Spatially Characterizing Visitor Use and Its Association with Informal Trails in Yosemite Valley Meadows

    NASA Astrophysics Data System (ADS)

    Walden-Schreiner, Chelsey; Leung, Yu-Fai

    2013-07-01

    Ecological impacts associated with nature-based recreation and tourism can compromise park and protected area goals if left unrestricted. Protected area agencies are increasingly incorporating indicator-based management frameworks into their management plans to address visitor impacts. Development of indicators requires empirical evaluation of indicator measures and examining their ecological and social relevance. This study addresses the development of the informal trail indicator in Yosemite National Park by spatially characterizing visitor use in open landscapes and integrating use patterns with informal trail condition data to examine their spatial association. Informal trail and visitor use data were collected concurrently during July and August of 2011 in three, high-use meadows of Yosemite Valley. Visitor use was clustered at statistically significant levels in all three study meadows. Spatial data integration found no statistically significant differences between use patterns and trail condition class. However, statistically significant differences were found between the distance visitors were observed from informal trails and visitor activity type with active activities occurring closer to trail corridors. Gender was also found to be significant with male visitors observed further from trail corridors. Results highlight the utility of integrated spatial analysis in supporting indicator-based monitoring and informing management of open landscapes. Additional variables for future analysis and methodological improvements are discussed.

  5. Information entropy to measure the spatial and temporal complexity of solute transport in heterogeneous porous media

    NASA Astrophysics Data System (ADS)

    Li, Weiyao; Huang, Guanhua; Xiong, Yunwu

    2016-04-01

    The complexity of the spatial structure of porous media, randomness of groundwater recharge and discharge (rainfall, runoff, etc.) has led to groundwater movement complexity, physical and chemical interaction between groundwater and porous media cause solute transport in the medium more complicated. An appropriate method to describe the complexity of features is essential when study on solute transport and conversion in porous media. Information entropy could measure uncertainty and disorder, therefore we attempted to investigate complexity, explore the contact between the information entropy and complexity of solute transport in heterogeneous porous media using information entropy theory. Based on Markov theory, two-dimensional stochastic field of hydraulic conductivity (K) was generated by transition probability. Flow and solute transport model were established under four conditions (instantaneous point source, continuous point source, instantaneous line source and continuous line source). The spatial and temporal complexity of solute transport process was characterized and evaluated using spatial moment and information entropy. Results indicated that the entropy increased as the increase of complexity of solute transport process. For the point source, the one-dimensional entropy of solute concentration increased at first and then decreased along X and Y directions. As time increased, entropy peak value basically unchanged, peak position migrated along the flow direction (X direction) and approximately coincided with the centroid position. With the increase of time, spatial variability and complexity of solute concentration increase, which result in the increases of the second-order spatial moment and the two-dimensional entropy. Information entropy of line source was higher than point source. Solute entropy obtained from continuous input was higher than instantaneous input. Due to the increase of average length of lithoface, media continuity increased, flow and

  6. On combining spectral and spatial information of hyperspectral image for camouflaged target detecting

    NASA Astrophysics Data System (ADS)

    Hua, Wenshen; Liu, Xun; Yang, Jia

    2013-12-01

    Detecting enemy's targets and being undetectable play increasingly important roles in modern warfare. Hyperspectral images can provide large spectral range and high spectral resolution, which are invaluable in discriminating between camouflaged targets and backgrounds. As supervised classification requires prior knowledge which cannot be acquired easily, unsupervised classification usually is adopted to process hyperspectral images to detect camouflaged target. But one of its drawbacks—low detecting accuracy confines its application for camouflaged target detecting. Most research on the processing of hyperspectral image tends to focus exclusively on spectral domain and ignores spatial domain. However current hyperspectral image provides high spatial resolution which contains useful information for camouflaged target detecting. A new method combining spectral and spatial information is proposed to increase the detecting accuracy using unsupervised classification. The method has two steps. In the first step, a traditional unsupervised classifier (i.e. K-MEANS, ISODATA) is adopted to classify the hyperspectral image to acquire basic classifications or clusters. During the second step, a 3×3 model and spectral angle mapping are utilized to test the spatial character of the hyperspectral image. The spatial character is defined as spatial homogeneity and calculated by spectral angle mapping. Theory analysis and experiment shows the method is reasonable and efficient. Camouflaged targets are extracted from the background and different camouflaged targets are also recognized. And the proposed algorithm outperforms K-MEANS in terms of detecting accuracy, robustness and edge's distinction. This paper demonstrates the new method is meaningful to camouflaged targets detecting.

  7. Challenges of Remote Sensing and Spatial Information Education and Technology Transfer in a Fast Developing Industry

    NASA Astrophysics Data System (ADS)

    Tsai, F.; Chen, L.-C.

    2014-04-01

    During the past decade, Taiwan has experienced an unusual and fast growing in the industry of mapping, remote sensing, spatial information and related markets. A successful space program and dozens of advanced airborne and ground-based remote sensing instruments as well as mobile mapping systems have been implemented and put into operation to support the vast demands of geospatial data acquisition. Moreover, in addition to the government agencies and research institutes, there are also tens of companies in the private sector providing geo-spatial data and services. However, the fast developing industry is also posing a great challenge to the education sector in Taiwan, especially the higher education for geo-spatial information. Facing this fast developing industry, the demands of skilled professionals and new technologies in order to address diversified needs are indubitably high. Consequently, while delighting in the expanding and prospering benefitted from the fast growing industry, how to fulfill these demands has become a challenge for the remote sensing and spatial information disciplines in the higher education institutes in Taiwan. This paper provides a brief insight into the status of the remote sensing and spatial information industry in Taiwan as well as the challenges of the education and technology transfer to support the increasing demands and to ensure the continuous development of the industry. In addition to the report of the current status of the remote sensing and spatial information related courses and programs in the colleges and universities, current and potential threatening issues and possible resolutions are also discussed in different points of view.

  8. Five on one side: personal and social information in spatial choice.

    PubMed

    Brown, Michael F; Saxon, Marie E; Bisbing, Teagan; Evans, Jessica; Ruff, Jennifer; Stokesbury, Andrew

    2015-03-01

    To examine whether the outcome of a rat's own choices ("personal information") and the choice behavior of another rat ("social information") can jointly control spatial choices, rats were tested in an open field task in which they searched for food. For the rats of primary interest (Subject Rats), the baited locations were all on one side of the arena, but the specific locations baited and the side on which they occurred varied over trials. The Subject Rats were sometimes tested together with an informed "Model" rat that had learned to find food in the same five locations (all on the same side of the arena) on every trial. Unintended perceptual cues apparently controlled spatial choices at first, but when perceptual cues to food location were not available, choices were controlled by both personal information (allowing the baited side of the arena to be determined) and social information (allowing baited locations to be determined more precisely). This shows that control by personal and social information are not mutually exclusive and supports the view that these two kinds of information can be used flexibly and adaptively to guide spatial choices. This article is part of a Special Issue entitled: tribute to Tom Zentall. PMID:25572458

  9. Using Geographic Information Systems to Reconceptualize Spatial Relationships and Ecological Context1

    PubMed Central

    Downey, Liam

    2011-01-01

    In this article, the author demonstrates how geographic information system (GIS) software can be used to reconceptualize spatial relationships and ecological context and address the modifiable areal unit problem. In order to do this, the author uses GIS to (1) test an important category of spatial hypotheses (spatial proximity hypotheses), (2) overcome methodological problems that arise when data sets are not spatially comparable, and (3) measure ecological context. The author introduces a set of GIS variable construction techniques that are designed to accomplish these tasks, illustrates these techniques empirically by using them to test spatial proximity hypotheses drawn from the literature on environmental inequality, and demonstrates that results obtained using these techniques are methodologically superior to and substantively different from results obtained using traditional techniques. Finally, the author demonstrates that these techniques are the product of an alternative conceptualization of physical space that allows sociologists to develop new ways to think about and measure spatial relationships, ecological context, and place-based social inequality and that gives them the ability to reconceptualize spatially based methodological problems that have confronted them for years. PMID:22021932

  10. Spatial uncertainty modeling of fuzzy information in images for pattern classification.

    PubMed

    Pham, Tuan D

    2014-01-01

    The modeling of the spatial distribution of image properties is important for many pattern recognition problems in science and engineering. Mathematical methods are needed to quantify the variability of this spatial distribution based on which a decision of classification can be made in an optimal sense. However, image properties are often subject to uncertainty due to both incomplete and imprecise information. This paper presents an integrated approach for estimating the spatial uncertainty of vagueness in images using the theory of geostatistics and the calculus of probability measures of fuzzy events. Such a model for the quantification of spatial uncertainty is utilized as a new image feature extraction method, based on which classifiers can be trained to perform the task of pattern recognition. Applications of the proposed algorithm to the classification of various types of image data suggest the usefulness of the proposed uncertainty modeling technique for texture feature extraction. PMID:25157744

  11. Overt is no better than covert when rehearsing visuo-spatial information in working memory.

    PubMed

    Godijn, Richard; Theeuwes, Jan

    2012-01-01

    In the present study, we examined whether eye movements facilitate retention of visuo-spatial information in working memory. In two experiments, participants memorised the sequence of the spatial locations of six digits across a retention interval. In some conditions, participants were free to move their eyes during the retention interval, but in others they either were required to remain fixated or were instructed to move their eyes exclusively to a selection of the memorised locations. Memory performance was no better when participants were free to move their eyes during the memory interval than when they fixated a single location. Furthermore, the results demonstrated a primacy effect in the eye movement behaviour that corresponded with the memory performance. We conclude that overt eye movements do not provide a benefit over covert attention for rehearsing visuo-spatial information in working memory. PMID:21769706

  12. Informational Masking and Spatial Hearing in Listeners with and without Unilateral Hearing Loss

    ERIC Educational Resources Information Center

    Rothpletz, Ann M.; Wightman, Frederic L.; Kistler, Doris J.

    2012-01-01

    Purpose: This study assessed selective listening for speech in individuals with and without unilateral hearing loss (UHL) and the potential relationship between spatial release from informational masking and localization ability in listeners with UHL. Method: Twelve adults with UHL and 12 normal-hearing controls completed a series of monaural and…

  13. Spatial and Social Diffusion of Information and Influence: Models and Algorithms

    ERIC Educational Resources Information Center

    Doo, Myungcheol

    2012-01-01

    In this dissertation research, we argue that spatial alarms and activity-based social networks are two fundamentally new types of information and influence diffusion channels. Such new channels have the potential of enriching our professional experiences and our personal life quality in many unprecedented ways. First, we develop an activity driven…

  14. Using a Sonified Topographic Approach to Communicate Spatial Information to People with Visual Impairments

    ERIC Educational Resources Information Center

    Thebpanya, Paporn

    2010-01-01

    This study implemented tactile interfaces with audio representations to convey spatial information on topographic maps. Two sound variables, pitch and duration, were incorporated with contour lines to represent various aspects of topographic features such as elevation, slope, profile, and landform. The effect of one sound variable (pitch) vs. a…

  15. Does Spatial or Visual Information in Maps Facilitate Text Recall?: Reconsidering the Conjoint Retention Hypothesis

    ERIC Educational Resources Information Center

    Griffin, Marlynn M.; Robinson, Daniel H.; Sarama, Julie

    2005-01-01

    The conjoint retention hypothesis (CRH) claims that students recall more text information when they study geographic maps in addition to text than when they study text alone, because the maps are encoded spatially (Kulhavy, Lee, & Caterino, 1985). This claim was recently challenged by Griffin and Robinson (2000), who found no advantage for maps…

  16. Ensemble Learning for Spatial Interpolation of Soil Potassium Content Based on Environmental Information

    PubMed Central

    Liu, Wei; Du, Peijun; Wang, Dongchen

    2015-01-01

    One important method to obtain the continuous surfaces of soil properties from point samples is spatial interpolation. In this paper, we propose a method that combines ensemble learning with ancillary environmental information for improved interpolation of soil properties (hereafter, EL-SP). First, we calculated the trend value for soil potassium contents at the Qinghai Lake region in China based on measured values. Then, based on soil types, geology types, land use types, and slope data, the remaining residual was simulated with the ensemble learning model. Next, the EL-SP method was applied to interpolate soil potassium contents at the study site. To evaluate the utility of the EL-SP method, we compared its performance with other interpolation methods including universal kriging, inverse distance weighting, ordinary kriging, and ordinary kriging combined geographic information. Results show that EL-SP had a lower mean absolute error and root mean square error than the data produced by the other models tested in this paper. Notably, the EL-SP maps can describe more locally detailed information and more accurate spatial patterns for soil potassium content than the other methods because of the combined use of different types of environmental information; these maps are capable of showing abrupt boundary information for soil potassium content. Furthermore, the EL-SP method not only reduces prediction errors, but it also compliments other environmental information, which makes the spatial interpolation of soil potassium content more reasonable and useful. PMID:25928138

  17. Ensemble learning for spatial interpolation of soil potassium content based on environmental information.

    PubMed

    Liu, Wei; Du, Peijun; Wang, Dongchen

    2015-01-01

    One important method to obtain the continuous surfaces of soil properties from point samples is spatial interpolation. In this paper, we propose a method that combines ensemble learning with ancillary environmental information for improved interpolation of soil properties (hereafter, EL-SP). First, we calculated the trend value for soil potassium contents at the Qinghai Lake region in China based on measured values. Then, based on soil types, geology types, land use types, and slope data, the remaining residual was simulated with the ensemble learning model. Next, the EL-SP method was applied to interpolate soil potassium contents at the study site. To evaluate the utility of the EL-SP method, we compared its performance with other interpolation methods including universal kriging, inverse distance weighting, ordinary kriging, and ordinary kriging combined geographic information. Results show that EL-SP had a lower mean absolute error and root mean square error than the data produced by the other models tested in this paper. Notably, the EL-SP maps can describe more locally detailed information and more accurate spatial patterns for soil potassium content than the other methods because of the combined use of different types of environmental information; these maps are capable of showing abrupt boundary information for soil potassium content. Furthermore, the EL-SP method not only reduces prediction errors, but it also compliments other environmental information, which makes the spatial interpolation of soil potassium content more reasonable and useful. PMID:25928138

  18. Visual Spatial Cognition in Neurodegenerative Disease

    PubMed Central

    Possin, Katherine L.

    2011-01-01

    Visual spatial impairment is often an early symptom of neurodegenerative disease; however, this multi-faceted domain of cognition is not well-assessed by most typical dementia evaluations. Neurodegenerative diseases cause circumscribed atrophy in distinct neural networks, and accordingly, they impact visual spatial cognition in different and characteristic ways. Anatomically-focused visual spatial assessment can assist the clinician in making an early and accurate diagnosis. This article will review the literature on visual spatial cognition in neurodegenerative disease clinical syndromes, and where research is available, by neuropathologic diagnoses. Visual spatial cognition will be organized primarily according to the following schemes: bottom-up / top-down processing, dorsal / ventral stream processing, and egocentric / allocentric frames of reference. PMID:20526954

  19. Developing an entropy-based model of spatial information estimation and its application in the design of precipitation gauge networks

    NASA Astrophysics Data System (ADS)

    Su, Ho-Ting; You, Gene Jiing-Yun

    2014-11-01

    This study proposed a spatial information estimation model for the analysis of precipitation gauge networks, to improve on previous methods based on information theory. The proposed model employs a two-dimensional transinformation-distance (T-D) relationship in conjunction with multivariate information approximation to estimate transinformation to ungauged locations from existing stations, while taking into consideration the influence of multiple stations and anisotropy. The proposed model is used to evaluate the spatial distribution of precipitation data and the characteristics of information transfer, which are then applied in a spatial optimization algorithm for the selection of additional station locations. This framework was implemented to investigate temporal and spatial patterns in information content in the Shihmen Reservoir watershed. The results demonstrate obvious anisotropy associated with the delivery of information. By comparing different cases, it was determined that the efficiency of information delivery dominates the spatial distribution of the information content, such that eccentricity is merely supplemental. Efficiency in information delivery is also heavily influenced by temporal scale. For data covering long intervals (monthly and annual), efficiency in the delivery of information is relatively high, while the uncertainty or heterogeneity of hourly or daily time series produces low spatial correlations due to the inefficient delivery of information. The proposed spatial optimization algorithm confirmed that the optimal location for new stations lies close to the center of low information zones. Additional stations could improve information content considerably; however, the margin of improvement decreases with the number of stations.

  20. EO-Based Spatial Information Systems in Support of Disaster Management

    NASA Astrophysics Data System (ADS)

    Venkatachary, K. V.; Rao, Mukund; Manikiam, B.; Navalgund, R. R.; Jayaraman, V.

    Space technology has introduced new dimensions into the study and understanding of Earth's processes and in Natural Disasters result from the dynamics of the outer parts of the earth's crust - resulting in cyclones, floods, earthquakes, landslides, volcanoes and many other natural hazards. On the other hand are the disasters resulting due to human activity - more due to un-planned management, and resulting in diseases and health hazards, collapse of major man-made structures (dams, buildings etc) and events beyond the control of mankind. All these result in extensive damage and loss to biological life and property - causing untold misery and disrupting the dynamics and quality of life. What is of critical importance is the organisation of an efficient Disaster Management System (DMS) - having a backbone of a comprehensive spatial information system and modelling system to support the needs of activities before a disaster strikes - preparedness and prediction and activities after the strike of a disaster - damage assessment and rehabilitation. A system-definition of the framework of a DMS is of utmost importance - providing a holistic and total view of a information support for a DMS and incorporating elements of the design and development an information system - mainly to support the information needs for preparedness, prediction, damage assessment, rehabilitation and research; networking - mainly to be able to speedily provide access to the information system at any point of time from any place and decision-making - to support speedy and efficient decisions being taken, actions implemented and feedback mechanisms. Major elements of the spatial information system would be the remote sensing images - with emphasis on "continuous observation and scanning" and enabling alert systems; a GIS database of critical parameters to provide alert information and also post-facto damage assessment and a GIS database for modeling the pre-disaster phase activities and

  1. Spatial unmasking of birdsong in human listeners: energetic and informational factors.

    PubMed

    Best, Virginia; Ozmeral, Erol; Gallun, Frederick J; Sen, Kamal; Shinn-Cunningham, Barbara G

    2005-12-01

    Spatial unmasking describes the improvement in the detection or identification of a target sound afforded by separating it spatially from simultaneous masking sounds. This effect has been studied extensively for speech intelligibility in the presence of interfering sounds. In the current study, listeners identified zebra finch song, which shares many acoustic properties with speech but lacks semantic and linguistic content. Three maskers with the same long-term spectral content but different short-term statistics were used: (1) chorus (combinations of unfamiliar zebra finch songs), (2) song-shaped noise (broadband noise with the average spectrum of chorus), and (3) chorus-modulated noise (song-shaped noise multiplied by the broadband envelope from a chorus masker). The amount of masking and spatial unmasking depended on the masker and there was evidence of release from both energetic and informational masking. Spatial unmasking was greatest for the statistically similar chorus masker. For the two noise maskers, there was less spatial unmasking and it was wholly accounted for by the relative target and masker levels at the acoustically better ear. The results share many features with analogous results using speech targets, suggesting that spatial separation aids in the segregation of complex natural sounds through mechanisms that are not specific to speech. PMID:16419821

  2. A spatial exploration of informal trail networks within Great Falls Park, VA

    USGS Publications Warehouse

    Wimpey, Jeremy; Marion, Jeffrey L.

    2011-01-01

    Informal (visitor-created) trails represent a threat to the natural resources of protected natural areas around the globe. These trails can remove vegetation, displace wildlife, alter hydrology, alter habitat, spread invasive species, and fragment landscapes. This study examines informal and formal trails within Great Falls Park, VA, a sub-unit of the George Washington Memorial Parkway, managed by the U.S. National Park Service. This study sought to answer three specific questions: 1) Are the physical characteristics and topographic alignments of informal trails significantly different from formal trails, 2) Can landscape fragmentation metrics be used to summarize the relative impacts of formal and informal trail networks on a protected natural area? and 3) What can we learn from examining the spatial distribution of the informal trails within protected natural areas? Statistical comparisons between formal and informal trails in this park indicate that informal trails have less sustainable topographic alignments than their formal counterparts. Spatial summaries of the lineal and areal extent and fragmentation associated with the trail networks by park management zones compare park management goals to the assessed attributes. Hot spot analyses highlight areas of high trail density within the park and findings provide insights regarding potential causes for development of dense informal trail networks.

  3. Spatial smoothing hurts localization but not information: pitfalls for brain mappers.

    PubMed

    Kamitani, Yukiyasu; Sawahata, Yasuhito

    2010-02-01

    Op de Beeck (Op de Beeck, H., 2009. Against hyperacuity in brain reading: Spatial smoothing does not hurt multivariate fMRI analyses? Neuroimage) challenges the possibility of extracting information from subvoxel representations via random biases associated with voxel sampling, the hypothesis proposed by Kamitani and Tong (Kamitani, Y., Tong, F., 2005. Decoding the visual and subjective contents of the human brain. Nat. Neurosci. 8, 679-685). Here, we show that his results provide no evidence against the possibility, being consistent with both of the subvoxel and supravoxel representation models. Classification of spatially smoothed fMRI data is not an effective means to probe into information sources for multivoxel decoding, since smoothing does not hurt the information contents of multivoxel patterns. We point out the danger of interpreting multivoxel decoding results based on intuitions guided by the conventional brain mapping paradigm. PMID:19559797

  4. Geographic information systems, remote sensing, and spatial analysis activities in Texas, 2002-07

    USGS Publications Warehouse

    Pearson, D.K.; Gary, R.H.; Wilson, Z.D.

    2007-01-01

    Geographic information system (GIS) technology has become an important tool for scientific investigation, resource management, and environmental planning. A GIS is a computer-aided system capable of collecting, storing, analyzing, and displaying spatially referenced digital data. GIS technology is particularly useful when analyzing a wide variety of spatial data such as with remote sensing and spatial analysis. Remote sensing involves collecting remotely sensed data, such as satellite imagery, aerial photography, or radar images, and analyzing the data to gather information or investigate trends about the environment or the Earth's surface. Spatial analysis combines remotely sensed, thematic, statistical, quantitative, and geographical data through overlay, modeling, and other analytical techniques to investigate specific research questions. It is the combination of data formats and analysis techniques that has made GIS an essential tool in scientific investigations. This document presents information about the technical capabilities and project activities of the U.S. Geological Survey (USGS) Texas Water Science Center (TWSC) GIS Workgroup from 2002 through 2007.

  5. Partial volume correction for arterial spin labeling data using spatial-temporal information

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Li, Baojuan; Zhang, Xi; Zhang, Linchuan; Liang, Zhengrong; Lu, Hongbing

    2015-03-01

    Arterial spin labeling (ASL) provides a noninvasive measurement of cerebral blood flow (CBF). Due to relatively low spatial resolution, the accuracy of CBF measurement is affected by the partial volume (PV) effect. In general ASL sequence, multiple scans of perfusion image pairs are acquired temporally to improve the signal to noise ratio. Several spatial PV correction methods have been proposed for the simple averaging of pair-difference images, while the perfusion information of gray matter and white matter existed in multiple image pairs was totally ignored. In this study, a statistical model of perfusion mixtures inside each voxel for the 4D ASL sequence is first proposed. To solve the model, a simplified method is proposed, in which the linear regression (LR) method is first used to obtain initial estimates of spatial correction, then an EM (expectation maximization) method is used to obtain accurate estimation using temporal information. The combination of LR and EM method (EM-LR) can effectively utilize the spatial-temporal information of ASL data for PV correction and provide a theoretical solution to estimate the perfusion mixtures. Both simulated and in vivo data were used to evaluate the performance of proposed method, which demonstrated its superiority on PV correction, edge preserving, and noise suppression.

  6. Pigeons can learn to make visual category discriminations using either low or high spatial frequency information.

    PubMed

    Lea, Stephen E G; Poser-Richet, Victoire; Meier, Christina

    2015-03-01

    Pigeons were trained to discriminate photographs of cat faces from dog faces, using either high- or low-pass spatial frequency filtered stimuli. Each pigeon was trained with multiple exemplars of the categories, but only with either high-pass or low-pass filtered stimuli. Not all pigeons reached the discrimination criterion. Successful pigeons were exposed in probe trials to test stimuli: cat and dog faces that had been subjected to the opposite kind of filtering from their training stimuli; the unfiltered original stimuli from which their training stimuli had been derived; and new exemplars of the cat- and dog-face categories, with the same filtering as was used in training. There was no transfer of discrimination to the stimuli with the opposite filtering from those used in training. Discrimination transferred, with some decrement, to the original unfiltered stimuli and to new exemplars with the same type of filtering as used in training. These results provide further evidence that both high and low spatial frequency information can be sufficient for pigeons to make category discriminations, and that there is no clear advantage for high spatial frequency information. They also confirm that high-pass and low-pass spatial frequency filtering produce images that have effectively no information in common. This article is part of a Special Issue entitled: Tribute to Tom Zentall. PMID:25447512

  7. Geographic Information Systems, Remote Sensing, and Spatial Analysis Activities in Texas, 2002-07

    USGS Publications Warehouse

    Pearson, D.K.; Gary, R.H.; Wilson, Z.D.

    2007-01-01

    Geographic information system (GIS) technology has become an important tool for scientific investigation, resource management, and environmental planning. A GIS is a computer-aided system capable of collecting, storing, analyzing, and displaying spatially referenced digital data. GIS technology is particularly useful when analyzing a wide variety of spatial data such as with remote sensing and spatial analysis. Remote sensing involves collecting remotely sensed data, such as satellite imagery, aerial photography, or radar images, and analyzing the data to gather information or investigate trends about the environment or the Earth's surface. Spatial analysis combines remotely sensed, thematic, statistical, quantitative, and geographical data through overlay, modeling, and other analytical techniques to investigate specific research questions. It is the combination of data formats and analysis techniques that has made GIS an essential tool in scientific investigations. This document presents information about the technical capabilities and project activities of the U.S. Geological Survey (USGS) Texas Water Science Center (TWSC) GIS Workgroup from 2002 through 2007.

  8. Examination of the Spatial Correlation of Statistics Information in the Ultrasonic Echo from Diseased Liver

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Tadashi; Hachiya, Hiroyuki; Kamiyama, Naohisa; Moriyasu, Fuminori

    2002-05-01

    To realize a quantitative diagnosis of liver cirrhosis, we have been analyzing the characteristics of echo amplitude in B-mode images. Realizing the distinction between liver diseases such as liver cirrhosis and chronic hepatitis is required in the field of medical ultrasonics. In this study, we examine the spatial correlation, with the coefficient of correlation between the frames and the amplitude characteristics of each frame, using the volumetric data of RF echo signals from normal and diseased liver. It is found that there is a relationship between the tissue structure of liver and the spatial correlation of echo information.

  9. Generalized information fusion and visualization using spatial voting and data modeling

    NASA Astrophysics Data System (ADS)

    Jaenisch, Holger M.; Handley, James W.

    2013-05-01

    We present a novel and innovative information fusion and visualization framework for multi-source intelligence (multiINT) data using Spatial Voting (SV) and Data Modeling. We describe how different sources of information can be converted into numerical form for further processing downstream, followed by a short description of how this information can be fused using the SV grid. As an illustrative example, we show the modeling of cyberspace as cyber layers for the purpose of tracking cyber personas. Finally we describe a path ahead for creating interactive agile networks through defender customized Cyber-cubes for network configuration and attack visualization.

  10. Design and realization of spatial information service system for government administration of natural disaster

    NASA Astrophysics Data System (ADS)

    Wang, Liang; Liu, Jiping; Zhu, Yi; Shi, Lihong

    2007-06-01

    The government of nearly every country have responsibility for administering the affairs of preventing and reducing the natural disasters. The geospatial character and positional connection of natural disasters information makes the geospatial information and GIS technology play a key role in government affairs increasingly. Based on project implementation and study of developing science and technology concerning reducing and preventing disasters in China, the paper is mainly on the comprehensive study of requirements analysis,construction pattern, primary assignments, main functions, important application and methods of Spatial Information Service System for Government Administration of Natural Disaster.

  11. Spatial inventory integrating raster databases and point sample data. [Geographic Information System for timber inventory

    NASA Technical Reports Server (NTRS)

    Strahler, A. H.; Woodcock, C. E.; Logan, T. L.

    1983-01-01

    A timber inventory of the Eldorado National Forest, located in east-central California, provides an example of the use of a Geographic Information System (GIS) to stratify large areas of land for sampling and the collection of statistical data. The raster-based GIS format of the VICAR/IBIS software system allows simple and rapid tabulation of areas, and facilitates the selection of random locations for ground sampling. Algorithms that simplify the complex spatial pattern of raster-based information, and convert raster format data to strings of coordinate vectors, provide a link to conventional vector-based geographic information systems.

  12. Trialling a web-based spatial information management tool with Land Managers in Victoria, Australia.

    PubMed

    Roberts, Anna M; Park, Geoff; Melland, Alice R; Miller, Ian

    2009-01-01

    A prototype web-based spatial information management tool (called eFarmer) was tested for its useability and usefulness by 46 Land Managers and 5 extension staff in Victoria, Australia. Participants had a range of enterprises (dairy, beef/sheep grazing, cropping, lifestyle land use), property sizes and computer ownership and expertise. A follow up study was conducted with 12 dairy farmers, where features regarding assessment of nutrient losses from paddocks (Farm Nutrient Loss Index, FNLI) were added to eFarmer. Over 27,000 maps (including 11,000 with aerial photography) were accessed by Land Managers during a 5-month trial period. Despite limited training and support, 1350 people are registered users, and approximately 700 have actively used the tool. Reasons for the success include providing improved access to spatial information, enabling measurement of farm features and creation of farm maps, providing a basis for decision-making about farm inputs, support for better farm and landscape scale action planning and production and Land Managers being able to seek management advice from the extension staff who facilitated eFarmer testing programs. For dairy farmers in the FNLI trial, awareness of off-site impacts increased and most changed management practices. Provision of on-going training and support will be at least as important as further development of the tool itself. Web-based spatial information tools have potential to improve the awareness of Land Managers about their environmental impacts and influence their decision-making. Access to spatial information has potential to reduce information asymmetry between Land Managers, extension staff and catchment planners in a constructive way. It will also change the role of extension staff away from being an expert with answers, to a facilitator enabling learning. Results have applicability in countries where there is a high level of farm computer ownership, relevant spatial information is available in GIS format

  13. When personality and culture clash: the psychological distress of allocentrics in an individualist culture and idiocentrics in a collectivist culture.

    PubMed

    Caldwell-Harris, Catherine L; Ayçiçegi, Ayse

    2006-09-01

    Because humans need both autonomy and interdependence, persons with either an extreme collectivist orientation (allocentrics) or extreme individualist values (idiocentrics) may be at risk for possession of some features of psychopathology. Is an extreme personality style a risk factor primarily when it conflicts with the values of the surrounding society? Individualism-collectivism scenarios and a battery of clinical and personality scales were administered to nonclinical samples of college students in Boston and Istanbul. For students residing in a highly individualistic society (Boston), collectivism scores were positively correlated with depression, social anxiety, obsessive-compulsive disorder and dependent personality. Individualism scores, particularly horizontal individualism, were negatively correlated with these same scales. A different pattern was obtained for students residing in a collectivist culture, Istanbul. Here individualism (and especially horizontal individualism) was positively correlated with scales for paranoid, schizoid, narcissistic, borderline and antisocial personality disorder. Collectivism (particularly vertical collectivism) was associated with low report of symptoms on these scales. These results indicate that having a personality style which conflicts with the values of society is associated with psychiatric symptoms. Having an orientation inconsistent with societal values may thus be a risk factor for poor mental health. PMID:17090622

  14. Superior spatial touch: improved haptic orientation processing in deaf individuals.

    PubMed

    van Dijk, Rick; Kappers, Astrid M L; Postma, Albert

    2013-10-01

    The present study investigated haptic spatial orientation processing in deaf signers, hearing sign language interpreters, and hearing controls. Blindfolded participants had to set two bars parallel in the horizontal plane, with either a 2-s or a 10-s delay between inspection of the reference bar and the setting of the test bar. The deaf group outperformed the other two groups which did not differ from each other. Together these results indicate that deaf individuals can better identify the allocentric spatial coordinates of haptically inspected orientations. These results are discussed in terms of the possible neurocognitive consequences of auditory deprivation. PMID:23897133

  15. Evidence from Visuomotor Adaptation for Two Partially Independent Visuomotor Systems

    ERIC Educational Resources Information Center

    Thaler, Lore; Todd, James T.

    2010-01-01

    Visual information can specify spatial layout with respect to the observer (egocentric) or with respect to an external frame of reference (allocentric). People can use both of these types of visual spatial information to guide their hands. The question arises if movements based on egocentric and movements based on allocentric visual information…

  16. Geographic information systems, remote sensing, and spatial analysis activities in Texas, 2008-09

    USGS Publications Warehouse

    U.S. Geological Survey

    2009-01-01

    Geographic information system (GIS) technology has become an important tool for scientific investigation, resource management, and environmental planning. A GIS is a computer-aided system capable of collecting, storing, analyzing, and displaying spatially referenced digital data. GIS technology is useful for analyzing a wide variety of spatial data. Remote sensing involves collecting remotely sensed data, such as satellite imagery, aerial photography, or radar images, and analyzing the data to gather information or investigate trends about the environment or the Earth's surface. Spatial analysis combines remotely sensed, thematic, statistical, quantitative, and geographical data through overlay, modeling, and other analytical techniques to investigate specific research questions. It is the combination of data formats and analysis techniques that has made GIS an essential tool in scientific investigations. This fact sheet presents information about the technical capabilities and project activities of the U.S. Geological Survey (USGS) Texas Water Science Center (TWSC) GIS Workgroup during 2008 and 2009. After a summary of GIS Workgroup capabilities, brief descriptions of activities by project at the local and national levels are presented. Projects are grouped by the fiscal year (October-September 2008 or 2009) the project ends and include overviews, project images, and Internet links to additional project information and related publications or articles.

  17. Spatial Data Quality Control Procedure applied to the Okavango Basin Information System

    NASA Astrophysics Data System (ADS)

    Butchart-Kuhlmann, Daniel

    2014-05-01

    Spatial data is a powerful form of information, capable of providing information of great interest and tremendous use to a variety of users. However, much like other data representing the 'real world', precision and accuracy must be high for the results of data analysis to be deemed reliable and thus applicable to real world projects and undertakings. The spatial data quality control (QC) procedure presented here was developed as the topic of a Master's thesis, in the sphere of and using data from the Okavango Basin Information System (OBIS), itself a part of The Future Okavango (TFO) project. The aim of the QC procedure was to form the basis of a method through which to determine the quality of spatial data relevant for application to hydrological, solute, and erosion transport modelling using the Jena Adaptable Modelling System (JAMS). As such, the quality of all data present in OBIS classified under the topics of elevation, geoscientific information, or inland waters, was evaluated. Since the initial data quality has been evaluated, efforts are underway to correct the errors found, thus improving the quality of the dataset.

  18. Study on multi-scale urban planning supported by spatial information technology

    NASA Astrophysics Data System (ADS)

    Dang, Anrong; He, Xindong; Li, Yongfu

    2008-10-01

    Considering the demand of urban and rural planning and the characteristics of spatial information technology (SIT), the study focuses on the application of SIT to support multi-scale urban planning. Three scales of urban and rural planning, such as city and town system planning, urban master planning, and detailed urban planning, were studied based on SIT. Firstly, tacking Great Beijing Region as an example, which includes Beijing, Tianjin, and northern of Hebei province, the city and town system planning was studied, supported by the theory of spatial interaction between cities and towns, and GIS spatial analysis. Then, for the urban master planning of Beijing, the RS and GIS were applied to do the spatial development analysis based on RS image data and GIS spatial analysis. Regarding to the conservation planning of Beijing's Inner city, the third scale is detailed urban planning. RS, GIS, and VR were integrated to determine the conservation region and digital conservation way as well. Finally, three conclusions were worked out.

  19. Egocentric mental transformation of self: effects of spatial relationship in mirror-image and anatomic imitations.

    PubMed

    Sudo, Tamami; Herai, Tomomitsu; Mogi, Ken

    2012-08-01

    Assessing the mental state of others by considering their perspective plays an important part in social communication. Imitation based on visual information represents a typical case of the translation of sensory input into action. Although humans are often successful in imitating complex actions, the mechanisms that underlie successful imitation are poorly understood. In earlier findings, it has been suggested that understanding others' minds through imitation is realized in the course of the comparison between the representations of the self and others, involving a transformation of the egocentric perspective to the allocentric one. There are two possible strategies of transformation between the representation of the self and others. One possible scenario is that the imitator perceives and imitates others as if looking in a mirror (mirror-image imitation, where, for example, the demonstrator's right hand corresponds to the imitator's left hand). Alternatively, the imitator might estimate the demonstrator's action using the anatomically congruent limb (anatomic imitation, where, for example, the demonstrator's right hand corresponds to the imitator's right hand). Here, we conducted a series of experiments in which the subjects imitated simple hand actions such as pushing a button presented from several different spatial orientations rotated at various angles. We observed that the imitators changed their strategy of imitation (mirror-image or anatomic imitation) depending on the nature of spatial configurations. Behavioral data from this study support the hypothesis that mirror-image and anatomic imitations provide complementary systems for understanding the actions and intentions of others. PMID:22729456

  20. Effects of decreasing resolution on spectral and spatial information content in an agricultural area. [Pottawatmie study site, Iowa and Nebraska

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The effects of decreasing spatial resolution from 6 1/4 miles square to 50 miles square are described. The effects of increases in cell size is studied on; the mean and variance of spectral data; spatial trends; and vegetative index numbers. Information content changes on cadastral, vegetal, soil, water and physiographic information are summarized.

  1. Design and implementation of relational and spatial databases for petroleum-related information

    SciTech Connect

    Schneider, R.; Sepehrnoori, K.; Wang, M.

    1987-01-01

    A relational database has been defined and implemented which describes the attributes and entities of engineering, geological, regulatory, economic, and historical data associated with the petroleum industry. This relational model allows the user to view this database of information from many different perspectives. An entity-relationship model was used to design the various relations of the database, and a data dictionary was developed to define the attributes of the database. Using the data model and data dictionary developed for the relational database, a spatial database was implemented which allows the user to graphically view the spatial relationships between various attributes of the database as well as additional information which may be computed from those attributes.

  2. A hybrid silicon membrane spatial light modulator for optical information processing

    NASA Technical Reports Server (NTRS)

    Pape, D. R.; Hornbeck, L. J.

    1984-01-01

    A new two dimensional, fast, analog, electrically addressable, silicon based membrane spatial light modulator (SLM) was developed for optical information processing applications. Coherent light reflected from the mirror elements is phase modulated producing an optical Fourier transform of an analog signal input to the device. The DMD architecture and operating parameters related to this application are presented. A model is developed that describes the optical Fourier transform properties of the DMD.

  3. A mobile agent approach to access and represent remote spatial information in LBS

    NASA Astrophysics Data System (ADS)

    Fang, Zhixiang; Li, Qingquan; Luo, Zhi; Geng, Xuexian

    2005-10-01

    The mobile computing based Location based Service (LBS) technology has been increasingly grown in the past decade; however there still exist some important constraints that complicate work with a mobile spatial information system. The limited resources in the mobile computing terminals would restrict some features that are available on the traditional computing technology. This paper will explores the use of a cooperative, distributed multi-agent systems (Java Agent Development Framework, JADE) to improve the efficiency of accessing and represent remote spatial information in mobile terminals and fixed terminal which support Java runtime environment (JRE), because that JADE system has following features: distributed agent platform, graphical user interface to manage several agents and agent containers form remote host, supporting to execution of multiple, parallel and concurrent agent activities via behavior model, FIPA-compliant platform including AMS (Agent Management System), DF (Directory Facilitator) and ACC (Agent Communication Channel), Efficient transport of ACL messages inside same agent system, library of FIPA interaction protocols ready to be used, FIPA-compliant naming service and supporting for application-defined content languages and ontology. An agile and flexible agent based approach for accessing and representing remote spatial information is proposed in this paper, mobile agent system architecture in LBS is presented, and a prototype system is given to shown that JADE makes this approach feasible and effective.

  4. Cultural background shapes spatial reference frame proclivity

    PubMed Central

    Goeke, Caspar; Kornpetpanee, Suchada; Köster, Moritz; Fernández-Revelles, Andrés B.; Gramann, Klaus; König, Peter

    2015-01-01

    Spatial navigation is an essential human skill that is influenced by several factors. The present study investigates how gender, age, and cultural background account for differences in reference frame proclivity and performance in a virtual navigation task. Using an online navigation study, we recorded reaction times, error rates (confusion of turning axis), and reference frame proclivity (egocentric vs. allocentric reference frame) of 1823 participants. Reaction times significantly varied with gender and age, but were only marginally influenced by the cultural background of participants. Error rates were in line with these results and exhibited a significant influence of gender and culture, but not age. Participants’ cultural background significantly influenced reference frame selection; the majority of North-Americans preferred an allocentric strategy, while Latin-Americans preferred an egocentric navigation strategy. European and Asian groups were in between these two extremes. Neither the factor of age nor the factor of gender had a direct impact on participants’ navigation strategies. The strong effects of cultural background on navigation strategies without the influence of gender or age underlines the importance of socialized spatial cognitive processes and argues for socio-economic analysis in studies investigating human navigation. PMID:26073656

  5. Estimation of spatially distributed turbulent heat fluxes using thermal information captured from an UAS

    NASA Astrophysics Data System (ADS)

    Brenner, Claire; Thiem, Christina Elisabeth; Bernhardt, Matthias; Schulz, Karsten

    2016-04-01

    Evapotranspiration is a key component of the Earth's water and energy cycle. However, measuring evapotranspiration is difficult and distributed information with high spatial resolution is rare. Land surface temperature (LST) is often used as source of data for the estimation of evapotranspiration. Actual LST is mainly controlled by the amount of incoming radiation, surface albedo, water availability, ventilation of the surface and in case of vegetation stands also by the intensity of the transpiration process. Thus it contains valuable information on the actual state of the soil-vegetation-atmosphere system. Typically LST information is available from satellite imagery or from radiometers installed at experimental sites. Thus, measured LST is either representative for areas of hundreds of square meters (satellites), or for certain points (radiometers). Thermal imaging from unmanned aerial systems (UAS) can be used for addressing this scale gap and is a trade-off between flexibility and ease of use on the one hand and spatial coverage on the other hand. In this study we have measured surface temperatures at a grassland site in Luxemburg in July 2015 by means of a thermal infrared camera mounted on an octocopter drone. At the same time scintillometer measurements were made at the same field. The experimental set-up was completed by meteorological and radiation measurements. UAS flights were conducted on a sequence of days over a time period of 2 weeks and with up to ten flights a day in order to monitor diurnal variation of LST. The observed spatially distributed surface temperatures were then used to estimate sensible and latent heat fluxes using three algorithms. All of them make use of observed vertical temperature gradients between surface and atmosphere but do show a different complexity. Two of them are single-source models while one is a dual-source representation of the soil-vegetation system. Although the experimental site was fully covered by grass, LST

  6. Are you sure the library is that way? Metacognitive monitoring of spatial judgments.

    PubMed

    Stevens, Christopher A; Carlson, Richard A

    2016-07-01

    Many studies have examined how people recall the locations of objects in spatial layouts. However, little is known about how people monitor the accuracy of judgments based on those memories. The goal of the present experiments was to examine the effect of reference frame characteristics on metacognitive accuracy for spatial judgments. Reference frame characteristics include the alignment of one's viewpoint with the structure of the environment (allocentric alignment), direction of the target with respect to one's current viewpoint (egocentric direction), and the type of perspective used to solve the task (egocentric vs. allocentric). Participants were tested on their knowledge of a well-known location in which they had experience navigating. They were asked to orient themselves toward a particular heading and point to target landmarks from this heading. They then rated their confidence in their pointing judgments. Confidence judgments were sensitive to the effects of allocentric alignment and egocentric direction on performance. However, they underestimate the magnitude of these effects. Follow-up regression analyses indicate that confidence in individual landmarks was a stronger predictor of confidence than reference frame characteristics. Overall, the results suggest that people use reference frame features and landmark confidence when monitoring performance in directional judgments. (PsycINFO Database Record PMID:26866660

  7. Selective 4D modelling framework for spatial-temporal land information management system

    NASA Astrophysics Data System (ADS)

    Doulamis, Anastasios; Soile, Sofia; Doulamis, Nikolaos; Chrisouli, Christina; Grammalidis, Nikos; Dimitropoulos, Kosmas; Manesis, Charalambos; Potsiou, Chryssy; Ioannidis, Charalabos

    2015-06-01

    This paper introduces a predictive (selective) 4D modelling framework where only the spatial 3D differences are modelled at the forthcoming time instances, while regions of no significant spatial-temporal alterations remain intact. To accomplish this, initially spatial-temporal analysis is applied between 3D digital models captured at different time instances. So, the creation of dynamic change history maps is made. Change history maps indicate spatial probabilities of regions needed further 3D modelling at forthcoming instances. Thus, change history maps are good examples for a predictive assessment, that is, to localize surfaces within the objects where a high accuracy reconstruction process needs to be activated at the forthcoming time instances. The proposed 4D Land Information Management System (LIMS) is implemented using open interoperable standards based on the CityGML framework. CityGML allows the description of the semantic metadata information and the rights of the land resources. Visualization aspects are also supported to allow easy manipulation, interaction and representation of the 4D LIMS digital parcels and the respective semantic information. The open source 3DCityDB incorporating a PostgreSQL geo-database is used to manage and manipulate 3D data and their semantics. An application is made to detect the change through time of a 3D block of plots in an urban area of Athens, Greece. Starting with an accurate 3D model of the buildings in 1983, a change history map is created using automated dense image matching on aerial photos of 2010. For both time instances meshes are created and through their comparison the changes are detected.

  8. Transmission Phase Holography: Spatial-Mode Filter Design for Quantum Information Applications

    NASA Astrophysics Data System (ADS)

    Hillmer, Rachel; Barreiro, Julio; Kwiat, Paul

    2007-03-01

    Photon spatial modes offer access to promising new applications in quantum information because they provide a higher-dimensional basis set than the usual two-dimensional one associated with polarization. Downconversion experiments have demonstrated spatial-mode entanglement [1], and even hyperentanglement in polarization and spatial mode [2]. However optical elements currently lack the refinement necessary to perform efficient, high-fidelity operations using spatial modes. Holographic filters for Laguerre-Gaussian and Hermite-Gaussian laser modes can act as modes converters, and have long been studied (under the terms ``modans'' and ``kinoforms'') for use in electrical engineering applications [3,4]. Her we present analytical refinements and optimizations of these techniques, with predicted mode fidelities over 95% and diffraction efficiencies up to 98%. Results of our experimental implementions of these solutions are presented. [1] Walborn, S.P, et al, ``Entanglement and conservation of orbital angular momentum in spontaneous parametric down-conversion,'' Phys. Rev. A 69, 023811 (2004); [2] Barreiro, J.T. et al, ``Generation of Hyperentangled Photon Pairs,'' Phys. Rev. Lett. 95, 260501 (2005); [3] Soifer, V.A., ``Methods of Computer Design of Diffractive Optical Elements,'' John Wiley & Sons, Inc., 2002; [4] Golub, M. and Soifer, V., ``Laser Beam Mode Selection by Computer Generated Holograms,'' CRC Press, Inc., 1994.

  9. Spatial analysis of lettuce downy mildew using geostatistics and geographic information systems.

    PubMed

    Wu, B M; van Bruggen, A H; Subbarao, K V; Pennings, G G

    2001-02-01

    ABSTRACT The epidemiology of lettuce downy mildew has been investigated extensively in coastal California. However, the spatial patterns of the disease and the distance that Bremia lactucae spores can be transported have not been determined. During 1995 to 1998, we conducted several field- and valley-scale surveys to determine spatial patterns of this disease in the Salinas valley. Geostatistical analyses of the survey data at both scales showed that the influence range of downy mildew incidence at one location on incidence at other locations was between 80 and 3,000 m. A linear relationship was detected between semivariance and lag distance at the field scale, although no single statistical model could fit the semi-variograms at the valley scale. Spatial interpolation by the inverse distance weighting method with a power of 2 resulted in plausible estimates of incidence throughout the valley. Cluster analysis in geographic information systems on the interpolated disease incidence from different dates demonstrated that the Salinas valley could be divided into two areas, north and south of Salinas City, with high and low disease pressure, respectively. Seasonal and spatial trends along the valley suggested that the distinction between the downy mildew conducive and nonconducive areas might be determined by environmental factors. PMID:18944386

  10. Informing surveillance programmes by investigating spatial dependency of subclinical Salmonella infection.

    PubMed

    Benschop, J; Stevenson, M A; Dahl, J; Morris, R S; French, N P

    2009-09-01

    The aim of this paper is to investigate local spatial dependency with regard to Salmonella seropositivity in data from the Danish swine salmonellosis control programme and its application in informing surveillance strategies. We applied inhomogeneous and observed-difference K-function estimation, and geo-statistical modelling to data from the Danish swine salmonellosis control programme. Slaughter-pig farm density showed large variation at both the country-wide and local level in Denmark (median 0.23, range 0.02-0.47 farms/km(2)). The spatial distribution of pig farms followed a random inhomogeneous Poisson process but was not aggregated. We found evidence for aggregation of Salmonella case farms over that of all farms at distances of up to 6 km and semivariogram analyses of Salmonella seropositivity revealed spatial dependency between pairs of farms up to 4 km apart. The strength of the spatial dependency was positively associated with slaughter-pig farm density. We proposed sampling more intensively those farms within a 4 km radius of farms that were identified with a high Salmonella status, and reduced sampling of farms that are within this radius of 'Salmonella-free' farms. Our approach has the potential to optimize sampling strategies while maintaining consumer confidence in food safety and also has potential to be used for other zoonotic disease surveillance systems. PMID:19224653

  11. Spatial and non-spatial determinants of successful tuberculosis treatment outcomes: An implication of Geographical Information Systems in health policy-making in a developing country.

    PubMed

    Kolifarhood, Goodarz; Khorasani-Zavareh, Davoud; Salarilak, Shaker; Shoghli, Alireza; Khosravi, Nasim

    2015-09-01

    This retrospective study aimed to address whether or to what extent spatial and non-spatial factors with a focus on a healthcare delivery system would influence successful tuberculosis (TB) treatment outcomes in Urmia, Iran. In this cross-sectional study, data of 452 new TB cases were extracted from Urmia TB Management Center during a 5-year period. Using the Geographical Information System (GIS), health centers and study subjects' locations were geocoded on digital maps. To identify the statistically significant geographical clusters, Average Nearest Neighbor (ANN) index was used. Logistic regression analysis was employed to determine the association of spatial and non-spatial variables on the occurrence of adverse treatment outcomes. The spatial clusters of TB cases were concentrated in older, impoverished and outskirts areas. Although there was a tendency toward higher odds of adverse treatment outcomes among urban TB cases, this finding after adjusting for distance from a given TB healthcare center did not reach statistically significant. This article highlights effects of spatial and non-spatial determinants on the TB adverse treatment outcomes, particularly in what way the policies of healthcare services are made. Accordingly, non-spatial determinants in terms of low socio-economic factors need more attention by public health policy makers, and then more focus should be placed on the health delivery system, in particular men's health. PMID:26231398

  12. Reduction of interference effect by low spatial frequency information priming in an emotional Stroop task.

    PubMed

    Beffara, Brice; Wicker, Bruno; Vermeulen, Nicolas; Ouellet, Marc; Bret, Amélie; Molina, Maria Jesus Funes; Mermillod, Martial

    2015-01-01

    The affective prediction hypothesis assumes that visual expectation allows fast and accurate processing of emotional stimuli. The prediction corresponds to what an object is likely to be. It therefore facilitates its identification by setting aside what the object is unlikely to be. It has then been suggested that prediction might be inevitably associated with the inhibition of irrelevant possibilities concerning the object to identify. Several studies highlighted that the facilitation of emotional perception depends on low spatial frequency (LSF) extraction. However, most of them used paradigms in which only the object to identify was present in the scene. As a consequence, there have yet been no studies investigating the efficiency of prediction in the visual perception of stimuli among irrelevant information. In this study, we designed a novel priming emotional Stroop task in which participants had to identify emotional facial expressions (EFEs) presented along with a congruent or incongruent word. To further investigate the role of early extraction of LSF information in top-down prediction during emotion recognition, the target EFE was primed with the same EFE filtered in LSF or high spatial frequency (HSF). Results reveal a reduction of the Stroop interference in the LSF compared to the HSF priming condition, which supports that visual expectation, depending on early LSF information extraction, facilitates the inhibition of irrelevant information during emotion recognition. PMID:26024463

  13. Spatial vision processes: From the optical image to the symbolic structures of contour information

    NASA Technical Reports Server (NTRS)

    Jobson, Daniel J.

    1988-01-01

    The significance of machine and natural vision is discussed together with the need for a general approach to image acquisition and processing aimed at recognition. An exploratory scheme is proposed which encompasses the definition of spatial primitives, intrinsic image properties and sampling, 2-D edge detection at the smallest scale, the construction of spatial primitives from edges, and the isolation of contour information from textural information. Concepts drawn from or suggested by natural vision at both perceptual and physiological levels are relied upon heavily to guide the development of the overall scheme. The scheme is intended to provide a larger context in which to place the emerging technology of detector array focal-plane processors. The approach differs from many recent efforts in edge detection and image coding by emphasizing smallest scale edge detection as a foundation for multi-scale symbolic processing while diminishing somewhat the importance of image convolutions with multi-scale edge operators. Cursory treatments of information theory illustrate that the direct application of this theory to structural information in images could not be realized.

  14. The effect of path length and display size on memory for spatial information.

    PubMed

    Guérard, Katherine; Tremblay, Sébastien

    2012-01-01

    In serial memory for spatial information, some studies showed that recall performance suffers when the distance between successive locations increases relatively to the size of the display in which they are presented (the path length effect; e.g., Parmentier et al., 2005) but not when distance is increased by enlarging the size of the display (e.g., Smyth & Scholey, 1994). In the present study, we examined the effect of varying the absolute and relative distance between to-be-remembered items on memory for spatial information. We manipulated path length using small (15″) and large (64″) screens within the same design. In two experiments, we showed that distance was disruptive mainly when it is varied relatively to a fixed reference frame, though increasing the size of the display also had a small deleterious effect on recall. The insertion of a retention interval did not influence these effects, suggesting that rehearsal plays a minor role in mediating the effects of distance on serial spatial memory. We discuss the potential role of perceptual organization in light of the pattern of results. PMID:22246063

  15. Effects of spatially correlated acoustic-tactile information on judgments of auditory circular direction

    NASA Astrophysics Data System (ADS)

    Cohen, Annabel J.; Lamothe, M. J. Reina; Toms, Ian D.; Fleming, Richard A. G.

    2002-05-01

    Cohen, Lamothe, Fleming, MacIsaac, and Lamoureux [J. Acoust. Soc. Am. 109, 2460 (2001)] reported that proximity governed circular direction judgments (clockwise/counterclockwise) of two successive tones emanating from all pairs of 12 speakers located at 30-degree intervals around a listeners' head (cranium). Many listeners appeared to experience systematic front-back confusion. Diametrically opposed locations (180-degrees-theoretically ambiguous direction) produced a direction bias pattern resembling Deutsch's tritone paradox [Deutsch, Kuyper, and Fisher, Music Percept. 5, 7992 (1987)]. In Experiment 1 of the present study, the circular direction task was conducted in the tactile domain using 12 circumcranial points of vibration. For all 5 participants, proximity governed direction (without front-back confusion) and a simple clockwise bias was shown for 180-degree pairs. Experiment 2 tested 9 new participants in one unimodal auditory condition and two bimodal auditory-tactile conditions (spatially-correlated/spatially-uncorrelated). Correlated auditory-tactile information eliminated front-back confusion for 8 participants and replaced the ``paradoxical'' bias for 180-degree pairs with the clockwise bias. Thus, spatially correlated audio-tactile location information improves the veridical representation of 360-degree acoustic space, and modality-specific principles are implicated by the unique circular direction bias patterns for 180-degree pairs in the separate auditory and tactile modalities. [Work supported by NSERC.

  16. Combining spatial and spectral information to improve crop/weed discrimination algorithms

    NASA Astrophysics Data System (ADS)

    Yan, L.; Jones, G.; Villette, S.; Paoli, J. N.; Gée, C.

    2012-01-01

    Reduction of herbicide spraying is an important key to environmentally and economically improve weed management. To achieve this, remote sensors such as imaging systems are commonly used to detect weed plants. We developed spatial algorithms that detect the crop rows to discriminate crop from weeds. These algorithms have been thoroughly tested and provide robust and accurate results without learning process but their detection is limited to inter-row areas. Crop/Weed discrimination using spectral information is able to detect intra-row weeds but generally needs a prior learning process. We propose a method based on spatial and spectral information to enhance the discrimination and overcome the limitations of both algorithms. The classification from the spatial algorithm is used to build the training set for the spectral discrimination method. With this approach we are able to improve the range of weed detection in the entire field (inter and intra-row). To test the efficiency of these algorithms, a relevant database of virtual images issued from SimAField model has been used and combined to LOPEX93 spectral database. The developed method based is evaluated and compared with the initial method in this paper and shows an important enhancement from 86% of weed detection to more than 95%.

  17. Implementation of data node in spatial information grid based on WS resource framework and WS notification

    NASA Astrophysics Data System (ADS)

    Zhang, Dengrong; Yu, Le

    2006-10-01

    Abstract-An approach of constructing a data node in spatial information grid (SIG) based on Web Service Resource Framework (WSRF) and Web Service Notification (WSN) is described in this paper. Attentions are paid to construct and implement SIG's resource layer, which is the most important part. A study on this layer find out, it is impossible to require persistent interaction with the clients of the services in common SIG architecture because of inheriting "stateless" and "not persistent" limitations of Web Service. A WSRF/WSN-based data node is designed to hurdle this short comes. Three different access modes are employed to test the availability of this node. Experimental results demonstrate this service node can successfully respond to standard OGC requests and returns specific spatial data in different network environment, also is stateful, dynamic and persistent.

  18. Soil Spatial Information and Production of Thematic Maps for the Northern Emirates, UAE

    NASA Astrophysics Data System (ADS)

    Abdelfattah, M. A.; Pain, C. F.

    2012-04-01

    Soil spatial data is an integral part of any effective agricultural research or advisory program. It provides information needed for planning and decision making processes. In many parts of the world, including the Northern Emirates of the United Arab Emirates, there is an ever increasing demand for digital soil and thematic maps of different scales. However, the existing data are either not available or not exhaustive and precise enough for use within a number of environmental applications. The reason for the lack of the spatial information is that conventional soil survey methods are relatively slow and very expensive. The present study highlights the generation of soil spatial information of the Northern Emirates and its use in the production of thematic maps through soil survey. The Soil Survey of the Northern Emirates was conducted between June 2010 and March 2012, and covered an area of about 400,000 ha. The objective was to prepare a soil map at 1:50,000 scale with associated data and information in a spatial and point database, the United Arab Emirates Soil Information System (UAESIS). Among other outputs, the survey information was used in an evaluation of the land for various uses to provide information that will help land use planning. The United States Department of Agriculture Soil Classification System (USDA Soil Taxonomy) has been used to classify the soils of the study area. Several land evaluations of both agricultural and non-agricultural land uses have been undertaken for the 1:50,000 scale map data and are presented in this study. These evaluations serve as base information for future land use planning and land management decision making. Irrigated agriculture suitability was evaluated using concepts developed by the Food and Agriculture Organization of the United Nations. Each soil map unit was allocated one of five ratings ranging from S1 (highly suitable) to N2 (permanently unsuitable), and an irrigated agriculture suitability map was

  19. Spatially weighted mutual information image registration for image guided radiation therapy

    SciTech Connect

    Park, Samuel B.; Rhee, Frank C.; Monroe, James I.; Sohn, Jason W.

    2010-09-15

    Purpose: To develop a new metric for image registration that incorporates the (sub)pixelwise differential importance along spatial location and to demonstrate its application for image guided radiation therapy (IGRT). Methods: It is well known that rigid-body image registration with mutual information is dependent on the size and location of the image subset on which the alignment analysis is based [the designated region of interest (ROI)]. Therefore, careful review and manual adjustments of the resulting registration are frequently necessary. Although there were some investigations of weighted mutual information (WMI), these efforts could not apply the differential importance to a particular spatial location since WMI only applies the weight to the joint histogram space. The authors developed the spatially weighted mutual information (SWMI) metric by incorporating an adaptable weight function with spatial localization into mutual information. SWMI enables the user to apply the selected transform to medically ''important'' areas such as tumors and critical structures, so SWMI is neither dominated by, nor neglects the neighboring structures. Since SWMI can be utilized with any weight function form, the authors presented two examples of weight functions for IGRT application: A Gaussian-shaped weight function (GW) applied to a user-defined location and a structures-of-interest (SOI) based weight function. An image registration example using a synthesized 2D image is presented to illustrate the efficacy of SWMI. The convergence and feasibility of the registration method as applied to clinical imaging is illustrated by fusing a prostate treatment planning CT with a clinical cone beam CT (CBCT) image set acquired for patient alignment. Forty-one trials are run to test the speed of convergence. The authors also applied SWMI registration using two types of weight functions to two head and neck cases and a prostate case with clinically acquired CBCT/MVCT image sets. The

  20. Entanglement generation and quantum information transfer between spatially-separated qubits in different cavities

    NASA Astrophysics Data System (ADS)

    Yang, Chui-Ping; Su, Qi-Ping; Nori, Franco

    2013-11-01

    The generation and control of quantum states of spatially-separated qubits distributed in different cavities constitute fundamental tasks in cavity quantum electrodynamics (QED). An interesting question in this context is how to prepare entanglement and realize quantum information transfer between qubits located at different cavities, which are important in large-scale quantum information processing. In this paper, we consider a physical system consisting of two cavities and three qubits. Two of the qubits are placed in two different cavities while the remaining one acts as a coupler, which is used to connect the two cavities. We propose an approach for generating quantum entanglement and implementing quantum information transfer between the two spatially-separated inter-cavity qubits. The quantum operations involved in this proposal are performed by a virtual photon process; thus the cavity decay is greatly suppressed during operations. In addition, to complete these tasks, only one coupler qubit and one operation step are needed. Moreover, there is no need to apply classical pulses, so that the engineering complexity is much reduced and the operation procedure is greatly simplified. Finally, our numerical results illustrate that high-fidelity implementation of this proposal using superconducting phase qubits and one-dimensional transmission line resonators is feasible for current circuit QED implementations. This proposal can also be applied to other types of superconducting qubits, including flux and charge qubits.

  1. A mobile mapping system for spatial information based on DGPS/EGIS

    NASA Astrophysics Data System (ADS)

    Pei, Ling; Wang, Qing; Gu, Juan

    2007-11-01

    With the rapid developments of mobile device and wireless communication, it brings a new challenge for acquiring the spatial information. A mobile mapping system based on differential global position system (DGPS) integrated with embedded geographic information system (EGIS) is designed. A mobile terminal adapts to various GPS differential environments such as single base mode and network GPS mode like Virtual Reference Station (VRS) and Master- Auxiliary Concept (MAC) by the mobile communication technology. The spatial information collected through DGPS is organized in an EGIS running in the embedded device. A set of mobile terminal in real-time DGPS based on GPRS adopting multithreading technique of serial port in manner of simulating overlapped I/O operating is developed, further more, the GPS message analysis and checkout based on Strategy Pattern for various receivers are included in the process of development. A mobile terminal accesses to the GPS network successfully by NTRIP (Networked Transport of RTCM via Internet Protocol) compliance. Finally, the accuracy and reliability of the mobile mapping system are proved by a lot of testing in 9 provinces all over the country.

  2. Enhanced and diminished visuo-spatial information processing in autism depends on stimulus complexity.

    PubMed

    Bertone, Armando; Mottron, Laurent; Jelenic, Patricia; Faubert, Jocelyn

    2005-10-01

    Visuo-perceptual processing in autism is characterized by intact or enhanced performance on static spatial tasks and inferior performance on dynamic tasks, suggesting a deficit of dorsal visual stream processing in autism. However, previous findings by Bertone et al. indicate that neuro-integrative mechanisms used to detect complex motion, rather than motion perception per se, may be impaired in autism. We present here the first demonstration of concurrent enhanced and decreased performance in autism on the same visuo-spatial static task, wherein the only factor dichotomizing performance was the neural complexity required to discriminate grating orientation. The ability of persons with autism was found to be superior for identifying the orientation of simple, luminance-defined (or first-order) gratings but inferior for complex, texture-defined (or second-order) gratings. Using a flicker contrast sensitivity task, we demonstrated that this finding is probably not due to abnormal information processing at a sub-cortical level (magnocellular and parvocellular functioning). Together, these findings are interpreted as a clear indication of altered low-level perceptual information processing in autism, and confirm that the deficits and assets observed in autistic visual perception are contingent on the complexity of the neural network required to process a given type of visual stimulus. We suggest that atypical neural connectivity, resulting in enhanced lateral inhibition, may account for both enhanced and decreased low-level information processing in autism. PMID:15958508

  3. Two-Microphone Noise Reduction Using Spatial Information-Based Spectral Amplitude Estimation

    NASA Astrophysics Data System (ADS)

    Li, Kai; Guo, Yanmeng; Fu, Qiang; Li, Junfeng; Yan, Yonghong

    Traditional two-microphone noise reduction algorithms to deal with highly nonstationary directional noises generally use the direction of arrival or phase difference information. The performance of these algorithms deteriorate when diffuse noises coexist with nonstationary directional noises in realistic adverse environments. In this paper, we present a two-channel noise reduction algorithm using a spatial information-based speech estimator and a spatial-information-controlled soft-decision noise estimator to improve the noise reduction performance in realistic non-stationary noisy environments. A target presence probability estimator based on Bayes rules using both phase difference and magnitude squared coherence is proposed for soft-decision of noise estimation, so that they can share complementary advantages when both directional noises and diffuse noises are present. Performances of the proposed two-microphone noise reduction algorithm are evaluated by noise reduction, log-spectral distance (LSD) and word recognition rate (WRR) of a distant-talking ASR system in a real room's noisy environment. Experimental results show that the proposed algorithm achieves better noises suppression without further distorting the desired signal components over the comparative dual-channel noise reduction algorithms.

  4. Integration of remotely sensed and model data to provide the spatial information basis for sustainable landuse

    NASA Astrophysics Data System (ADS)

    Backhaus, R.; Braun, G.

    Sustainable development is by now generally accepted as the paramount objective of environmental policy. Environmental applications of Earth observation, on the other hand, have been successfully demonstrated over a wide range of monitoring activities, mostly with the aim of describing the spatial distribution and time course of geophysical parameters and land surface structures. With landuse structures being of major influence on the sustainability of terrestrial ecosystems, and being also a highly suitable object of Earth observation, it is still an open question, however, in which way Earth observation data can be processed and integrated to provide an approximate indicator of sustainability. Based on an ecological sustainability model developed by Ripl and his co-workers at Berlin Technical University, this question was investigated in the framework of the joint project "Development of a Land-Water-Management Concept to Decrease Matter Losses to Open Waters" (Stör project), which was funded by the German Federal Ministry of Research and Technology. Present results may be summarized as follows: 1. Apart from hydrological point measurements, there are several spatial parameters which are of indicative value as to sustainability, especially the spatio-temporal distribution of biomass, surface temperature, and precipitation. 2. To provide the spatial information basis for enhanced efficiency of immediate measures such as reforestation, agricultural extension etc., a global information system (GIS) concept was developed and demonstrated which is based on a landuse/vegetation classification derived from Landsat TM data, a digital evaluation mode (DEM) and a relief dependent water distribution model (WDM). Further implications such as the organisation of information systems which are to serve sustainability strategies are discussed.

  5. Rest boosts the long-term retention of spatial associative and temporal order information.

    PubMed

    Craig, Michael; Dewar, Michaela; Della Sala, Sergio; Wolbers, Thomas

    2015-09-01

    People retain more new verbal episodic information for at least 7 days if they rest for a few minutes after learning than if they attend to new information. It is hypothesized that rest allows for superior consolidation of new memories. In rodents, rest periods promote hippocampal replay of a recently travelled route, and this replay is thought to be critical for memory consolidation and subsequent spatial navigation. If rest boosts human memory by promoting hippocampal replay/consolidation, then the beneficial effect of rest should extend to complex (hippocampal) memory tasks, for example, tasks probing associations and sequences. We investigated this question via a virtual reality route memory task. Healthy young participants learned two routes to a 100% criterion. One route was followed by a 10-min rest and the other by a 10-min spot the difference game. For each learned route, participants performed four delayed spatial memory tests probing: (i) associative (landmark-direction) memory, (ii) cognitive map formation, (iii) temporal (landmark) order memory, and (iv) route memory. Tests were repeated after 7 days to determine any long-term effects. No effect of rest was detected in the route memory or cognitive map tests, most likely due to ceiling and floor effects, respectively. Rest did, however, boost retention in the associative memory and temporal order memory tests, and this boost remained for at least 7 days. We therefore demonstrate that the benefit of rest extends to (spatial) associative and temporal order memory in humans. We hypothesise that rest allows superior consolidation/hippocampal replay of novel information pertaining to a recently learned route, thus boosting new memories over the long term. PMID:25620400

  6. D Visualization of Volcanic Ash Dispersion Prediction with Spatial Information Open Platform in Korea

    NASA Astrophysics Data System (ADS)

    Youn, J.; Kim, T.

    2016-06-01

    Visualization of disaster dispersion prediction enables decision makers and civilian to prepare disaster and to reduce the damage by showing the realistic simulation results. With advances of GIS technology and the theory of volcanic disaster prediction algorithm, the predicted disaster dispersions are displayed in spatial information. However, most of volcanic ash dispersion predictions are displayed in 2D. 2D visualization has a limitation to understand the realistic dispersion prediction since its height could be presented only by colour. Especially for volcanic ash, 3D visualization of dispersion prediction is essential since it could bring out big aircraft accident. In this paper, we deals with 3D visualization techniques of volcanic ash dispersion prediction with spatial information open platform in Korea. First, time-series volcanic ash 3D position and concentrations are calculated with WRF (Weather Research and Forecasting) model and Modified Fall3D algorithm. For 3D visualization, we propose three techniques; those are 'Cube in the air', 'Cube in the cube', and 'Semi-transparent plane in the air' methods. In the 'Cube in the Air', which locates the semitransparent cubes having different color depends on its particle concentration. Big cube is not realistic when it is zoomed. Therefore, cube is divided into small cube with Octree algorithm. That is 'Cube in the Cube' algorithm. For more realistic visualization, we apply 'Semi-transparent Volcanic Ash Plane' which shows the ash as fog. The results are displayed in the 'V-world' which is a spatial information open platform implemented by Korean government. Proposed techniques were adopted in Volcanic Disaster Response System implemented by Korean Ministry of Public Safety and Security.

  7. Spatial interpolation of soil organic carbon using apparent electrical conductivity as secondary information

    NASA Astrophysics Data System (ADS)

    Martinez, G.; Vanderlinden, K.; Ordóñez, R.; Muriel, J. L.

    2009-04-01

    Soil organic carbon (SOC) spatial characterization is necessary to evaluate under what circumstances soil acts as a source or sink of carbon dioxide. However, at the field or catchment scale it is hard to accurately characterize its spatial distribution since large numbers of soil samples are necessary. As an alternative, near-surface geophysical sensor-based information can improve the spatial estimation of soil properties at these scales. Electromagnetic induction (EMI) sensors provide non-invasive and non-destructive measurements of the soil apparent electrical conductivity (ECa), which depends under non-saline conditions on clay content, water content or SOC, among other properties that determine the electromagnetic behavior of the soil. This study deals with the possible use of ECa-derived maps to improve SOC spatial estimation by Simple Kriging with varying local means (SKlm). Field work was carried out in a vertisol in SW Spain. The field is part of a long-term tillage experiment set up in 1982 with three replicates of conventional tillage (CT) and Direct Drilling (DD) plots with unitary dimensions of 15x65m. Shallow and deep (up to 0.8m depth) apparent electrical conductivity (ECas and ECad, respectively) was measured using the EM38-DD EMI sensor. Soil samples were taken from the upper horizont and analyzed for their SOC content. Correlation coefficients of ECas and ECad with SOC were low (0.331 and 0.175) due to the small range of SOC values and possibly also to the different support of the ECa and SOC data. Especially the ECas values were higher in the DD plots. The normalized ECa difference (ΔECa), calculated as the difference between the normalized ECas and ECad values, distinguished clearly the CT and DD plots, with the DD plots showing positive ΔECa values and CT plots ΔECa negative values. The field was stratified using fuzzy k-means (FKM) classification of ΔECa (FKM1), and ECas and ECad (FKM2). The FKM1 map mainly showed the difference between

  8. Behavioral response to contamination risk information in a spatially explicit groundwater environment: Experimental evidence

    NASA Astrophysics Data System (ADS)

    Li, Jingyuan; Michael, Holly A.; Duke, Joshua M.; Messer, Kent D.; Suter, Jordan F.

    2014-08-01

    This paper assesses the effectiveness of aquifer monitoring information in achieving more sustainable use of a groundwater resource in the absence of management policy. Groundwater user behavior in the face of an irreversible contamination threat is studied by applying methods of experimental economics to scenarios that combine a physics-based, spatially explicit, numerical groundwater model with different representations of information about an aquifer and its risk of contamination. The results suggest that the threat of catastrophic contamination affects pumping decisions: pumping is significantly reduced in experiments where contamination is possible compared to those where pumping cost is the only factor discouraging groundwater use. The level of information about the state of the aquifer also affects extraction behavior. Pumping rates differ when information that synthesizes data on aquifer conditions (a "risk gauge") is provided, despite invariant underlying economic incentives, and this result does not depend on whether the risk information is location-specific or from a whole aquifer perspective. Interestingly, users increase pumping when the risk gauge signals good aquifer status compared to a no-gauge treatment. When the gauge suggests impending contamination, however, pumping declines significantly, resulting in a lower probability of contamination. The study suggests that providing relatively simple aquifer condition guidance derived from monitoring data can lead to more sustainable use of groundwater resources.

  9. The effect of AMPA receptor blockade on spatial information acquisition, consolidation and expression in juvenile rats.

    PubMed

    Tzakis, Nikolaos; Bosnic, Tim; Ritchie, Thomas; Dixon, Kaylyn; Holahan, Matthew R

    2016-09-01

    Improvement on spatial tasks in rats is observed during a late, postnatal developmental period (post-natal day (PND) 18 - PND 20). The developmental emergence of this spatial function occurs in conjunction with hippocampal connectivity changes and enhanced hippocampal-AMPA receptor-mediated synaptic responses. The current work investigated the effect of AMPAr blockade on the emergence and long-term storage of spatial information in juvenile rats and associated neural activity patterns in the dorsal hippocampus CA1 region. Male, Long Evans rats between the ages of PND 18 and PND 20 were systemically (i.p.) administered the AMPAr antagonist, NBQX, (0, 5 or 10mg/kg) every day prior to hidden platform water maze training (PND 18, 19 and 20), every day immediately post-training or immediately before the probe test (PND 41). NBQX administration prior to training prolonged latencies, pathlength and increased thigmotaxis during the acquisition phase. Administration of NBQX immediately posttraining had no effect on the day-to-day performance. When given a probe test 3weeks later, the saline group across all conditions spent more time in the target quadrant. Rats treated with pretraining 5mg NBQX dose showed a preference for the target quadrant while the posttraining and pretesting 5mg NBQX doses impaired the target quadrant preference. Groups injected with 10mg of NBQX pretraining, posttraining or pretesting did not show a preference for the target quadrant. c-Fos labeling in the CA1 reflected these differences in probe performance in that groups showing greater than chance dwell time in the target quadrant showed more c-Fos labeling in the CA1 region than groups that did not show a target quadrant preference. These findings provide support for the critical role of AMPA receptor-mediated function in the organization and long-term storage of spatial memories acquired during the juvenile period. PMID:27353718

  10. Glycan structures contain information for the spatial arrangement of glycoproteins in the plasma membrane.

    PubMed

    Hall, M Kristen; Weidner, Douglas A; Chen, Jian ming; Bernetski, Christopher J; Schwalbe, Ruth A

    2013-01-01

    Glycoconjugates at the cell surface are crucial for cells to communicate with each other and the extracellular microenvironment. While it is generally accepted that glycans are vectorial biopolymers, their information content is unclear. This report provides evidence that distinct N-glycan structures influence the spatial arrangement of two integral membrane glycoproteins, Kv3.1 and E-cadherin, at the adherent membrane which in turn alter cellular properties. Distinct N-glycan structures were generated by heterologous expression of these glycoproteins in parental and glycosylation mutant Chinese hamster ovary cell lines. Unlike the N-linked glycans, the O-linked glycans of the mutant cell lines are similar to those of the parental cell line. Western and lectin blots of total membranes and GFP immunopurified samples, combined with glycosidase digestion reactions, were employed to verify the glycoproteins had predominantly complex, oligomannose, and bisecting type N-glycans from Pro(-)5, Lec1, and Lec10B cell lines, respectively. Based on total internal reflection fluorescence and differential interference contrast microscopy techniques, and cellular assays of live parental and glycosylation mutant CHO cells, we propose that glycoproteins with complex, oligomannose or bisecting type N-glycans relay information for localization of glycoproteins to various regions of the plasma membrane in both a glycan-specific and protein-specific manner, and furthermore cell-cell interactions are required for deciphering much of this information. These distinct spatial arrangements also impact cell adhesion and migration. Our findings provide direct evidence that N-glycan structures of glycoproteins contribute significantly to the information content of cells. PMID:24040379

  11. Geotechnical parameter spatial distribution stochastic analysis based on multi-precision information assimilation

    NASA Astrophysics Data System (ADS)

    Wang, C.; Rubin, Y.

    2014-12-01

    Spatial distribution of important geotechnical parameter named compression modulus Es contributes considerably to the understanding of the underlying geological processes and the adequate assessment of the Es mechanics effects for differential settlement of large continuous structure foundation. These analyses should be derived using an assimilating approach that combines in-situ static cone penetration test (CPT) with borehole experiments. To achieve such a task, the Es distribution of stratum of silty clay in region A of China Expo Center (Shanghai) is studied using the Bayesian-maximum entropy method. This method integrates rigorously and efficiently multi-precision of different geotechnical investigations and sources of uncertainty. Single CPT samplings were modeled as a rational probability density curve by maximum entropy theory. Spatial prior multivariate probability density function (PDF) and likelihood PDF of the CPT positions were built by borehole experiments and the potential value of the prediction point, then, preceding numerical integration on the CPT probability density curves, the posterior probability density curve of the prediction point would be calculated by the Bayesian reverse interpolation framework. The results were compared between Gaussian Sequential Stochastic Simulation and Bayesian methods. The differences were also discussed between single CPT samplings of normal distribution and simulated probability density curve based on maximum entropy theory. It is shown that the study of Es spatial distributions can be improved by properly incorporating CPT sampling variation into interpolation process, whereas more informative estimations are generated by considering CPT Uncertainty for the estimation points. Calculation illustrates the significance of stochastic Es characterization in a stratum, and identifies limitations associated with inadequate geostatistical interpolation techniques. This characterization results will provide a multi

  12. Spatial resolution, signal-to-noise and information capacity of linear imaging systems.

    PubMed

    Gureyev, Timur; Nesterets, Yakov; de Hoog, Frank

    2016-07-25

    A simple model for image formation in linear shift-invariant systems is considered, in which both the detected signal and the noise variance are varying slowly compared to the point-spread function of the system. It is shown that within the constraints of this model, the square of the signal-to-noise ratio is always proportional to the "volume" of the spatial resolution unit. In the case of Poisson statistics, the ratio of these two quantities divided by the incident density of the imaging particles (e.g. photons) represents a dimensionless invariant of the imaging system, which was previously termed the intrinsic imaging quality. The relationship of this invariant to the notion of information capacity of communication and imaging systems, which was previously considered by Shannon, Gabor and others, is investigated. The results are then applied to a simple generic model of quantitative imaging of weakly scattering objects, leading to an estimate of the upper limit for the amount of information about the sample that can be obtained in such experiments. It is shown that this limit depends only on the total number of imaging particles incident on the sample, the average scattering coefficient, the size of the sample and the number of spatial resolution units. PMID:27464167

  13. The Neural Bases of the Semantic Interference of Spatial Frequency-based Information in Scenes.

    PubMed

    Kauffmann, Louise; Bourgin, Jessica; Guyader, Nathalie; Peyrin, Carole

    2015-12-01

    Current models of visual perception suggest that during scene categorization, low spatial frequencies (LSF) are processed rapidly and activate plausible interpretations of visual input. This coarse analysis would then be used to guide subsequent processing of high spatial frequencies (HSF). The present fMRI study examined how processing of LSF may influence that of HSF by investigating the neural bases of the semantic interference effect. We used hybrid scenes as stimuli by combining LSF and HSF from two different scenes, and participants had to categorize the HSF scene. Categorization was impaired when LSF and HSF scenes were semantically dissimilar, suggesting that the LSF scene was processed automatically and interfered with categorization of the HSF scene. fMRI results revealed that this semantic interference effect was associated with increased activation in the inferior frontal gyrus, the superior parietal lobules, and the fusiform and parahippocampal gyri. Furthermore, a connectivity analysis (psychophysiological interaction) revealed that the semantic interference effect resulted in increasing connectivity between the right fusiform and the right inferior frontal gyri. Results support influential models suggesting that, during scene categorization, LSF information is processed rapidly in the pFC and activates plausible interpretations of the scene category. These coarse predictions would then initiate top-down influences on recognition-related areas of the inferotemporal cortex, and these could interfere with the categorization of HSF information in case of semantic dissimilarity to LSF. PMID:26244724

  14. Remote sensing, geographical information system and spatial analysis for schistosomiasis epidemiology and ecology in Africa.

    PubMed

    Simoonga, C; Utzinger, J; Brooker, S; Vounatsou, P; Appleton, C C; Stensgaard, A S; Olsen, A; Kristensen, T K

    2009-11-01

    Beginning in 1970, the potential of remote sensing (RS) techniques, coupled with geographical information systems (GIS), to improve our understanding of the epidemiology and control of schistosomiasis in Africa, has steadily grown. In our current review, working definitions of RS, GIS and spatial analysis are given, and applications made to date with RS and GIS for the epidemiology and ecology of schistosomiasis in Africa are summarised. Progress has been made in mapping the prevalence of infection in humans and the distribution of intermediate host snails. More recently, Bayesian geostatistical modelling approaches have been utilized for predicting the prevalence and intensity of infection at different scales. However, a number of challenges remain; hence new research is needed to overcome these limitations. First, greater spatial and temporal resolution seems important to improve risk mapping and understanding of transmission dynamics at the local scale. Second, more realistic risk profiling can be achieved by taking into account information on people's socio-economic status; furthermore, future efforts should incorporate data on domestic access to clean water and adequate sanitation, as well as behavioural and educational issues. Third, high-quality data on intermediate host snail distribution should facilitate validation of infection risk maps and modelling transmission dynamics. Finally, more emphasis should be placed on risk mapping and prediction of multiple species parasitic infections in an effort to integrate disease risk mapping and to enhance the cost-effectiveness of their control. PMID:19627627

  15. Dose convolution filter: Incorporating spatial dose information into tissue response modeling

    SciTech Connect

    Huang Yimei; Joiner, Michael; Zhao Bo; Liao Yixiang; Burmeister, Jay

    2010-03-15

    Purpose: A model is introduced to integrate biological factors such as cell migration and bystander effects into physical dose distributions, and to incorporate spatial dose information in plan analysis and optimization. Methods: The model consists of a dose convolution filter (DCF) with single parameter {sigma}. Tissue response is calculated by an existing NTCP model with DCF-applied dose distribution as input. The authors determined {sigma} of rat spinal cord from published data. The authors also simulated the GRID technique, in which an open field is collimated into many pencil beams. Results: After applying the DCF, the NTCP model successfully fits the rat spinal cord data with a predicted value of {sigma}=2.6{+-}0.5 mm, consistent with 2 mm migration distances of remyelinating cells. Moreover, it enables the appropriate prediction of a high relative seriality for spinal cord. The model also predicts the sparing of normal tissues by the GRID technique when the size of each pencil beam becomes comparable to {sigma}. Conclusions: The DCF model incorporates spatial dose information and offers an improved way to estimate tissue response from complex radiotherapy dose distributions. It does not alter the prediction of tissue response in large homogenous fields, but successfully predicts increased tissue tolerance in small or highly nonuniform fields.

  16. The role of spatial frequency information in the recognition of facial expressions of pain.

    PubMed

    Wang, Shan; Eccleston, Christopher; Keogh, Edmund

    2015-09-01

    Being able to detect pain from facial expressions is critical for pain communication. Alongside identifying the specific facial codes used in pain recognition, there are other types of more basic perceptual features, such as spatial frequency (SF), which refers to the amount of detail in a visual display. Low SF carries coarse information, which can be seen from a distance, and high SF carries fine-detailed information that can only be perceived when viewed close up. As this type of basic information has not been considered in the recognition of pain, we therefore investigated the role of low-SF and high-SF information in the decoding of facial expressions of pain. Sixty-four pain-free adults completed 2 independent tasks: a multiple expression identification task of pain and core emotional expressions and a dual expression "either-or" task (pain vs fear, pain vs happiness). Although both low-SF and high-SF information make the recognition of pain expressions possible, low-SF information seemed to play a more prominent role. This general low-SF bias would seem an advantageous way of potential threat detection, as facial displays will be degraded if viewed from a distance or in peripheral vision. One exception was found, however, in the "pain-fear" task, where responses were not affected by SF type. Together, this not only indicates a flexible role for SF information that depends on task parameters (goal context) but also suggests that in challenging visual conditions, we perceive an overall affective quality of pain expressions rather than detailed facial features. PMID:26075962

  17. Part 4 Technology and the future of GIS and spatial analysis. Geographic Information Science: New methods and technology

    NASA Astrophysics Data System (ADS)

    Frank, Andrew U.

    Geographical Information Science is essentially computational geography and has its own research program, namely all aspects of formal models for spatial natural processes and the interaction of humans with the environment in space and time. This is not a question of technology and technology-related research; but technology influences what questions can be researched effectively. Collection of data in the field and the simulation of field experience through Virtual Reality are just two questions of how spatial reality and human experience are linked. The focus on human spatial cognition is similarly found in software engineering for interoperable Geographic Information Systems.

  18. Application of high spatial resolution airborne hyperspectral remote sensing data in thematic information extraction

    NASA Astrophysics Data System (ADS)

    Xu, Hong-gen; Ma, Hong-chao; Li, De-ren; Song, Yan

    2006-10-01

    The airborne hyperspectral remote sensing data, such as PHI, OMIS, has the virtues of high spatial and spectral resolution. Hence, from the view of target classification we can consider that it can provide the ability of discriminating targets more detailedly than other data. So it's important to extract thematic information and update database using this kind of data. Whereas, the hyperspectral data has abundant bands and high between-band correlation, the traditional classification methods such as maximum likelihood classifier (MLC) and spectral angle mapper (SAM) have performed poorly in thematic information extraction. For this reason, we present a new method for thematic information extraction with hyperspectral remote sensing data. We perform classification by means of combining the self-organizing map (SOM) neural network which is considered as full-pixel technique with linear spectral mixture analysis (LSMA) which is considered as mixed-pixel technique. The SOM neural network is improved from some aspects to classify the pure data and find the mixed data. And then the mixed data are unmixed and classified by LSMA. The result of experiment shows that we can have the better performance in thematic information extraction with PHI by this means.

  19. Extracting temporal and spatial information from remotely sensed data for mapping wildlife habitat

    NASA Astrophysics Data System (ADS)

    Wallace, Cynthia S. A.

    autocorrelation of the image, permitting classification of all pixels into coherent units whose signature graphs exhibit a classic variogram shape. The variogram parameters captured in these signatures have been shown in previous studies to discriminate between different species-specific vegetation associations. The synoptic view of the landscape provided by satellite data can inform resource management efforts. The ability to characterize the spatial structure and temporal dynamics of habitat using repeatable remote sensing data allows closer monitoring of the relationship between a species and its landscape.

  20. Spatially resolved information on karst conduit flow from in-cave dye-tracing

    NASA Astrophysics Data System (ADS)

    Lauber, U.; Ufrecht, W.; Goldscheider, N.

    2013-09-01

    Artificial tracers are powerful tools to investigate karst systems. Tracers are commonly injected into sinking streams or dolines, while springs serve as monitoring sites. The obtained flow and transport parameters represent mixed information from the vadose, epiphreatic and phreatic zones, i.e., the aquifer remains a black box. Accessible active caves constitute valuable but underexploited natural laboratories to gain detailed insights into the hydrologic functioning of the aquifer. Two multi-tracer tests in the catchment of a major karst spring (Blautopf, Germany) with injections and monitoring in two associated water caves aimed at obtaining spatially and temporally resolved information on groundwater flow in different compartments of the system. Two tracers were injected in the caves to characterize the hydraulic connections between them and with the spring. Two injections at the land surface, far from the spring, aimed at resolving the aquifer's internal drainage structure. Tracer breakthrough curves were monitored by field fluorimeters in caves and at the spring. Results demonstrate the dendritic drainage structure of the aquifer. It was possible to obtain relevant flow and transport parameters for different sections of this system. The highest mean flow velocities (275 m h-1) were observed in the near-spring epiphreatic section (open-channel flow), while velocities in the phreatic zone (pressurized flow) were one order of magnitude lower. Determined conduit water volumes confirm results of water balances and hydrograph analyses. In conclusion, experiments and monitoring in caves can deliver spatially resolved information on karst aquifer heterogeneity and dynamics that cannot be obtained by traditional investigative methods.

  1. Spatially resolved information on karst conduit flow from in-cave dye tracing

    NASA Astrophysics Data System (ADS)

    Lauber, U.; Ufrecht, W.; Goldscheider, N.

    2014-02-01

    Artificial tracers are powerful tools for investigating karst systems. Tracers are commonly injected into sinking streams or dolines, while springs serve as monitoring sites. The obtained flow and transport parameters represent mixed information from the vadose, epiphreatic and phreatic zones (that is, the aquifer remains a black box). Accessible active caves constitute valuable but underexploited natural laboratories to gain detailed insights into the hydrologic functioning of the aquifer. Two multi-tracer tests in the catchment of a major karst spring (Blautopf, Germany) with injections and monitoring in two associated water caves aimed at obtaining spatially and temporally resolved information on groundwater flow in different compartments of the system. Two tracers were injected into the caves to characterize the hydraulic connections between them and with the spring. Two injections at the land surface, far from the spring, aimed at resolving the aquifer's internal drainage structure. Tracer breakthrough curves were monitored by field fluorimeters in caves and at the spring. Results demonstrate the dendritic drainage structure of the aquifer. It was possible to obtain relevant flow and transport parameters for different sections of this system. The highest mean flow velocities (275 m h-1) were observed in the near-spring epiphreatic section (open-channel flow), while velocities in the phreatic zone (pressurized flow) were one order of magnitude lower. Determined conduit water volumes confirm results of water balances and hydrograph analyses. In conclusion, experiments and monitoring in caves can deliver spatially resolved information on karst aquifer heterogeneity and dynamics that cannot be obtained by traditional investigative methods.

  2. 3D constrained inversion of geophysical and geological information applying Spatial Mutually Constrained Inversion.

    NASA Astrophysics Data System (ADS)

    Nielsen, O. F.; Ploug, C.; Mendoza, J. A.; Martínez, K.

    2009-05-01

    The need for increaseding accuracy and reduced ambiguities in the inversion results has resulted in focus on the development of more advanced inversion methods of geophysical data. Over the past few years more advanced inversion techniques have been developed to improve the results. Real 3D-inversion is time consuming and therefore often not the best solution in a cost-efficient perspective. This has motivated the development of 3D constrained inversions, where 1D-models are constrained in 3D, also known as a Spatial Constrained Inversion (SCI). Moreover, inversion of several different data types in one inversion has been developed, known as Mutually Constrained Inversion (MCI). In this paper a presentation of a Spatial Mutually Constrained Inversion method (SMCI) is given. This method allows 1D-inversion applied to different geophysical datasets and geological information constrained in 3D. Application of two or more types of geophysical methods in the inversion has proved to reduce the equivalence problem and to increase the resolution in the inversion results. The use of geological information from borehole data or digital geological models can be integrated in the inversion. In the SMCI, a 1D inversion code is used to model soundings that are constrained in three dimensions according to their relative position in space. This solution enhances the accuracy of the inversion and produces distinct layers thicknesses and resistivities. It is very efficient in the mapping of a layered geology but still also capable of mapping layer discontinuities that are, in many cases, related to fracturing and faulting or due to valley fills. Geological information may be included in the inversion directly or used only to form a starting model for the individual soundings in the inversion. In order to show the effectiveness of the method, examples are presented from both synthetic data and real data. The examples include DC-soundings as well as land-based and airborne TEM

  3. GeoSpatial Workforce Development: enhancing the traditional learning environment in geospatial information technology

    NASA Astrophysics Data System (ADS)

    Lawhead, Pamela B.; Aten, Michelle L.

    2003-04-01

    The Center for GeoSpatial Workforce Development is embarking on a new era in education by developing a repository of dynamic online courseware authored by the foremost industry experts within the remote sensing and GIS industries. Virtual classrooms equipped with the most advanced instructions, computations, communications, course evaluation, and management facilities amplify these courses to enhance the learning environment and provide rapid feedback between instructors and students. The launch of this program included the objective development of the Model Curriculum by an independent consortium of remote sensing industry leaders. The Center's research and development focus on recruiting additional industry experts to develop the technical content of the courseware and then utilize state-of-the-art technology to enhance their material with visually stimulating animations, compelling audio clips and entertaining, interactive exercises intended to reach the broadest audience possible by targeting various learning styles. The courseware will be delivered via various media: Internet, CD-ROM, DVD, and compressed video, that translates into anywhere, anytime delivery of GeoSpatial Information Technology education.

  4. Real-time target detection in hyperspectral images based on spatial-spectral information extraction

    NASA Astrophysics Data System (ADS)

    Zhang, Bing; Yang, Wei; Gao, Lianru; Chen, Dongmei

    2012-12-01

    Recently, real-time image data processing is a popular research area for hyperspectral remote sensing. In particular, target detection surveillance, which is an important military application of hyperspectral remote sensing, demands real-time or near real-time processing. The massive amount of hyperspectral image data seriously limits the processing speed. In this article, a strategy named spatial-spectral information extraction (SSIE) is presented to accelerate hyperspectral image processing. SSIE is composed of band selection and sample covariance matrix estimation. Band selection fully utilizes the high-spectral correlation in spectral image, while sample covariance matrix estimation fully utilizes the high-spatial correlation in remote sensing image. To overcome the inconsistent and irreproducible shortage of random distribution, we present an effective scalar method to select sample pixels. Meanwhile, we have implemented this target detection algorithm based on the SSIE strategy on the hardware of a digital signal processor (DSP). The implementation of a constrained energy minimization algorithm is composed of hardware and software architectures. The hardware architecture contains chips and peripheral interfaces, while software architecture contains a data transferring model. In the experiments, we compared the performance of hardware of DSP with that of Environment for Visualizing Images software. DSP speed up the data processing and also results in more effective in terms of recognition rate, which demonstrate that the SSIE implemented by DSP is sufficient to enable near real-time supervised target detection.

  5. DSP design for real-time hyperspectral target detection based on spatial-spectral information extraction

    NASA Astrophysics Data System (ADS)

    Yang, Wei; Zhang, Bing; Gao, Lianru; Wu, Yuanfeng

    2012-06-01

    Military target detection is an important application of hyperspectral remote sensing. It highly demands real-time or near real-time processing. However, the massive amount of hyperspectral image data seriously limits the processing speed. Real-time image processing based on hardware platform, such as digital signal processor (DSP), is one of recent developments in hyperspectral target detection. In hyperspectral target detection algorithms, correlation matrix or covariance matrix calculation is always used to whiten data, which is a very time-consuming process. In this paper, a strategy named spatial-spectral information extraction (SSIE) is presented to accelerate the speed of hyperspectral image processing. The strategy is composed of bands selection and sample covariance matrix estimation. Bands selection fully utilizes the high-spectral correlation in spectral image, while sample covariance matrix estimation fully utilizes the high-spatial correlation in remote sensing image. Meanwhile, this strategy is implemented on the hardware platform of DSP. The hardware implementation of constrained energy minimization (CEM) algorithm is composed of hardware architecture and software architecture. The hardware architecture contains chips and peripheral interfaces, and software architecture establishes a data transferring model to accomplish the communication between DSP and PC. In experiments, the performance on software of ENVI with that on hardware of DSP is compared. Results show that the processing speed and recognition result on DSP are better than those on ENVI. Detection results demonstrate that the strategy implemented by DSP is sufficient to enable near real-time supervised target detection.

  6. Subsurface information for risk-sensitive urban spatial planning in Dhaka Metropolitan City, Bangladesh

    NASA Astrophysics Data System (ADS)

    Günther, Andreas; Aziz Patwary, Mohammad Abdul; Bahls, Rebecca; Asaduzzaman, Atm; Ludwig, Rüdiger; Ashraful Kamal, Mohammad; Nahar Faruqa, Nurun; Jabeen, Sarwat

    2016-04-01

    Dhaka Metropolitan City (including Dhaka and five adjacent municipal areas) is one of the fastest developing urban regions in the world. Densely build-up areas in the developed metropolitan area of Dhaka City are subject to extensive restructuring as common six- or lower storied buildings are replaced by higher and heavier constructions. Additional stories are built on existing houses, frequently exceeding the allowable bearing pressure on the subsoil as supported by the foundations. In turn, newly developing city areas are projected in marshy terrains modified by extensive, largely unengineered landfills. In most areas, these terrains bear unfavorable building ground conditions within 30 meters. Within a collaborative technical cooperation project between Bangladesh and Germany, BGR supports GSB in the provision of geo-information for the Capital Development Authority (RAJUK). For general urban planning, RAJUK successively develops a detailed area plan (DAP) at scale 1 : 50000 for the whole Dhaka Metropolitan City area (approx. 1700 km2). Geo-information have not been considered in the present DAP. Within the project, geospatial information in form of a geomorphic map, a digital terrain model and a 3-D subsurface model covering the whole city area have been generated at a scale of 1 : 50000. An extensive engineering geological data base consisting of more than 2200 borehole data with associated Standard Penetration Testing (SPT) and lab data has been compiled. With the field testing (SPT) and engineering geological lab data, the 3-D subsurface model can be parameterized to derive important spatial subsurface information for urban planning like bearing capacity evaluations for different foundation designs or soil liquefaction potential assessments for specific earthquake scenarios. In conjunction with inundation potential evaluations for different flooding scenarios, comprehensive building ground suitability information can be derived to support risk

  7. An Intelligent Spatial Proximity System Using Neurofuzzy Classifiers and Contextual Information

    NASA Astrophysics Data System (ADS)

    Barouni, F.; Moulin, B.

    2014-11-01

    In this paper, we propose a novel approach to reason with spatial proximity. The approach is based on contextual information and uses a neurofuzzy classifier to handle the uncertainty aspect of proximity. Neurofuzzy systems are a combination of neural networks and fuzzy systems and incorporate the advantages of both techniques. Although fuzzy systems are focused on knowledge representation, they do not allow the estimation of membership functions. Conversely, neuronal networks use powerful learning techniques but they are not able to explain how results are obtained. Neurofuzzy systems benefit from both techniques by using training data to generate membership functions and by using fuzzy rules to represent expert knowledge. Moreover, contextual information is collected from a knowledge base. The complete solution that we propose is integrated in a GIS, enhancing it with proximity reasoning. From an application perspective, the proposed approach was used in the telecommunication domain and particularly in fiber optic monitoring systems. In such systems, a user needs to qualify the distance between a fiber break and the surrounding objects of the environment to optimize the assignment of emergency crews. The neurofuzzy classifier has been used to compute the membership function parameters of the contextual information inputs using a training data set and fuzzy rules.

  8. HIGH SPATIAL RESOLUTION SURVEY OF GRAIN SIZE INFORMATION ON RIVER BED BY IMAGE PROCESSING

    NASA Astrophysics Data System (ADS)

    Ohashi, Keisuke; Ihara, Kazuki; Yasuda, Shingo

    We tried a method of grain sizing by image processing which is available to survey and analyze in short time. The high-efficiency method actualizes high spatial resolution information of grain size distribution. Thus, the information has a vailability to express a situation of stream flow better than traditional grain sizing methods. For this reason, we paid attention to 50 m reservoir area upper from the check dam in mountainous region and surveyed the grain distribution at 26 sites and river channel landform. The grain sizing by image processing provided the appropriate result qualitatively. Moreover we estimated the critical diameter of moving from hydraulic information simultaneously. A qualitative appropriate result is showed less than 50 mm error as a result, however, quantitative response is not found between the critical diameter of moving and the grain size distribution surveyed. Meanwhile,the different grain sizing methods that are image processing and traditional sieving are used to cover the bilateral weak point. Thereby, a peak of grain existence probability is found in the threshold diameter between image processing and sieving. This result indicates that it is necessary to change the threshold diameter much larger than the limit of image processing grain sizing.

  9. Video segmentation using spatial proximity, color, and motion information for region-based coding

    NASA Astrophysics Data System (ADS)

    Hong, Won H.; Kim, Nam Chul; Lee, Sang-Mi

    1994-09-01

    An efficient video segmentation algorithm with homogeneity measure to incorporate spatial proximity, color, and motion information simultaneously is presented for region-based coding. The procedure toward complete segmentation consists of two steps: primary segmentation, and secondary segmentation. In the primary segmentation, an input image is finely segmented by FSCL. In the secondary segmentation, a lot of small regions and similar regions generated in the preceding step are eliminated or merged by a fast RSST. Through some experiments, it is found that the proposed algorithm produces efficient segmentation results and the video coding system with this algorithm yields visually acceptable quality and PSNR equals 36 - 37 dB at a very low bitrate of about 13.2 kbits/s.

  10. A concept-based interactive biomedical image retrieval approach using visualness and spatial information

    NASA Astrophysics Data System (ADS)

    Rahman, Md M.; Antani, Sameer K.; Demner-Fushman, Dina; Thoma, George R.

    2015-03-01

    This paper presents a novel approach to biomedical image retrieval by mapping image regions to local concepts and represent images in a weighted entropy-based concept feature space. The term concept refers to perceptually distinguishable visual patches that are identified locally in image regions and can be mapped to a glossary of imaging terms. Further, the visual significance (e.g., visualness) of concepts is measured as Shannon entropy of pixel values in image patches and is used to refine the feature vector. Moreover, the system can assist user in interactively select a Region-Of-Interest (ROI) and search for similar image ROIs. Further, a spatial verification step is used as a post-processing step to improve retrieval results based on location information. The hypothesis that such approaches would improve biomedical image retrieval, is validated through experiments on a data set of 450 lung CT images extracted from journal articles from four different collections.

  11. Local rank-based spatial information for improvement of remote sensing hyperspectral imaging resolution.

    PubMed

    Zhang, Xin; Juan, Anna de; Tauler, Romà

    2016-01-01

    This paper shows the effect of using local rank and selectivity constraints based on spatial information of spectroscopic images to increase the performance of Multivariate Curve Resolution (MCR) methods and to decrease the ambiguity of final results. Fixed Size Image Window-Evolving Factor Analysis (FSIW-EFA) is applied to discover which pixels are more suitable for the application of local rank constraints. An automated method to help in setting appropriate threshold values for the application of FSIW-EFA, based on global and local use of Singular Value Decomposition (SVD) is proposed. Additional use of correlation coefficients between selected reference spectra and pixel spectra of the image is shown to provide an alternative way for the application of the selectivity constraint in spectroscopic images for the first time. This alternative method resulted to be satisfactory when pure pixels exist. PMID:26695226

  12. The protagonist's first perspective influences the encoding of spatial information in narratives.

    PubMed

    Hatzipanayioti, Adamantini; Galati, Alexia; Avraamides, Marios N

    2016-03-01

    Three experiments examined the first-perspective alignment effect that is observed when retrieving spatial information from memory about described environments. Participants read narratives that described the viewpoint of a protagonist in fictitious environments and then pointed to the memorized locations of described objects from imagined perspectives. Results from Experiments 1 and 2 showed that performance was best when participants responded from the protagonist's first perspective even though object locations were described from a different perspective. In Experiment 3, in which participants were physically oriented with the perspective used to describe object locations, performance from that description perspective was better than that from the protagonist's first perspective, which was, in turn, better than performance from other perspectives. These findings suggest that when reading narratives, people default to using a reference frame that is aligned with their own facing direction, although physical movement may facilitate retrieval from other perspectives. PMID:26068697

  13. Real-Time Cardiac MRI using Prior Spatial-Spectral Information

    PubMed Central

    Brinegar, Cornelius; Zhang, Haosen; Wu, Yi-Jen L.; Foley, Lesley M.; Hitchens, T. Kevin; Ye, Qing; Pocci, Darren; Lam, Fan; Ho, Chien; Liang, Zhi-Pei

    2009-01-01

    Cardiac MRI performed while the patient is breathing is typically achieved using non-real-time techniques such as ECG triggering with respiratory gating; however, modern dynamic imaging techniques are beginning to enable this type of imaging in real-time. One of these dynamic imaging techniques is based on forming a Partially Separable Function (PSF) model of the data, but the model fitting process is known to be sensitive even when truncated SVD regularization is used. As a result, physiologically meaningless artifacts can appear in the dynamic images when the total number of measurements is limited. To address this issue, the dynamic imaging problem is formulated as a generalized Tikhonov regularization problem with the PSF model as a component of the forward data model, and a penalty function is used to introduce spatial-spectral prior information. This new method both reduces data acquisition requirements and improves stability relative to the original PSF based method when applied to cardiac MRI. PMID:19964109

  14. Real-time cardiac MRI using prior spatial-spectral information.

    PubMed

    Brinegar, Cornelius; Zhang, Haosen; Wu, Yi-Jen L; Foley, Lesley M; Hitchens, T; Ye, Qing; Pocci, Darren; Lam, Fan; Ho, Chien; Liang, Zhi-Pei

    2009-01-01

    Cardiac MRI performed while the patient is breathing is typically achieved using non-real-time techniques such as ECG triggering with respiratory gating; however, modern dynamic imaging techniques are beginning to enable this type of imaging in real-time. One of these dynamic imaging techniques is based on forming a Partially Separable Function (PSF) model of the data, but the model fitting process is known to be sensitive even when truncated SVD regularization is used. As a result, physiologically meaningless artifacts can appear in the dynamic images when the total number of measurements is limited. To address this issue, the dynamic imaging problem is formulated as a generalized Tikhonov regularization problem with the PSF model as a component of the forward data model, and a penalty function is used to introduce spatial-spectral prior information. This new method both reduces data acquisition requirements and improves stability relative to the original PSF based method when applied to cardiac MRI. PMID:19964109

  15. Toward Soil Spatial Information Systems (SSIS) for global modeling and ecosystem management

    NASA Technical Reports Server (NTRS)

    Baumgardner, Marion F.

    1995-01-01

    The general objective is to conduct research to contribute toward the realization of a world soils and terrain (SOTER) database, which can stand alone or be incorporated into a more complete and comprehensive natural resources digital information system. The following specific objectives are focussed on: (1) to conduct research related to (a) translation and correlation of different soil classification systems to the SOTER database legend and (b) the inferfacing of disparate data sets in support of the SOTER Project; (2) to examine the potential use of AVHRR (Advanced Very High Resolution Radiometer) data for delineating meaningful soils and terrain boundaries for small scale soil survey (range of scale: 1:250,000 to 1:1,000,000) and terrestrial ecosystem assessment and monitoring; and (3) to determine the potential use of high dimensional spectral data (220 reflectance bands with 10 m spatial resolution) for delineating meaningful soils boundaries and conditions for the purpose of detailed soil survey and land management.

  16. An efficient representation of spatial information for expert reasoning in robotic vehicles

    NASA Technical Reports Server (NTRS)

    Scott, Steven; Interrante, Mark

    1987-01-01

    The previous generation of robotic vehicles and drones was designed for a specific task, with limited flexibility in executing their mission. This limited flexibility arises because the robotic vehicles do not possess the intelligence and knowledge upon which to make significant tactical decisions. Current development of robotic vehicles is toward increased intelligence and capabilities, adapting to a changing environment and altering mission objectives. The latest techniques in artificial intelligence (AI) are being employed to increase the robotic vehicle's intelligent decision-making capabilities. This document describes the design of the SARA spatial database tool, which is composed of request parser, reasoning, computations, and database modules that collectively manage and derive information useful for robotic vehicles.

  17. Spatial characterization and prediction of Neanderthal sites based on environmental information and stochastic modelling

    NASA Astrophysics Data System (ADS)

    Maerker, Michael; Bolus, Michael

    2014-05-01

    We present a unique spatial dataset of Neanderthal sites in Europe that was used to train a set of stochastic models to reveal the correlations between the site locations and environmental indices. In order to assess the relations between the Neanderthal sites and environmental variables as described above we applied a boosted regression tree approach (TREENET) a statistical mechanics approach (MAXENT) and support vector machines. The stochastic models employ a learning algorithm to identify a model that best fits the relationship between the attribute set (predictor variables (environmental variables) and the classified response variable which is in this case the types of Neanderthal sites. A quantitative evaluation of model performance was done by determining the suitability of the model for the geo-archaeological applications and by helping to identify those aspects of the methodology that need improvements. The models' predictive performances were assessed by constructing the Receiver Operating Characteristics (ROC) curves for each Neanderthal class, both for training and test data. In a ROC curve the Sensitivity is plotted over the False Positive Rate (1-Specificity) for all possible cut-off points. The quality of a ROC curve is quantified by the measure of the parameter area under the ROC curve. The dependent variable or target variable in this study are the locations of Neanderthal sites described by latitude and longitude. The information on the site location was collected from literature and own research. All sites were checked for site accuracy using high resolution maps and google earth. The study illustrates that the models show a distinct ranking in model performance with TREENET outperforming the other approaches. Moreover Pre-Neanderthals, Early Neanderthals and Classic Neanderthals show a specific spatial distribution. However, all models show a wide correspondence in the selection of the most important predictor variables generally showing less

  18. Spectral Doppler estimation utilizing 2-D spatial information and adaptive signal processing.

    PubMed

    Ekroll, Ingvild K; Torp, Hans; Løvstakken, Lasse

    2012-06-01

    The trade-off between temporal and spectral resolution in conventional pulsed wave (PW) Doppler may limit duplex/triplex quality and the depiction of rapid flow events. It is therefore desirable to reduce the required observation window (OW) of the Doppler signal while preserving the frequency resolution. This work investigates how the required observation time can be reduced by adaptive spectral estimation utilizing 2-D spatial information obtained by parallel receive beamforming. Four adaptive estimation techniques were investigated, the power spectral Capon (PSC) method, the amplitude and phase estimation (APES) technique, multiple signal classification (MUSIC), and a projection-based version of the Capon technique. By averaging radially and laterally, the required covariance matrix could successfully be estimated without temporal averaging. Useful PW spectra of high resolution and contrast could be generated from ensembles corresponding to those used in color flow imaging (CFI; OW = 10). For a given OW, the frequency resolution could be increased compared with the Welch approach, in cases in which the transit time was higher or comparable to the observation time. In such cases, using short or long pulses with unfocused or focused transmit, an increase in temporal resolution of up to 4 to 6 times could be obtained in in vivo examples. It was further shown that by using adaptive signal processing, velocity spectra may be generated without high-pass filtering the Doppler signal. With the proposed approach, spectra retrospectively calculated from CFI may become useful for unfocused as well as focused imaging. This application may provide new clinical information by inspection of velocity spectra simultaneously from several spatial locations. PMID:22711413

  19. A Rapid Monitoring and Evaluation Method of Schistosomiasis Based on Spatial Information Technology.

    PubMed

    Wang, Yong; Zhuang, Dafang

    2015-12-01

    Thanks to Spatial Information Technologies (SITs) such as Remote Sensing (RS) and Geographical Information System (GIS) that are being quickly developed and updated, SITs are being used more widely in the public health field. The use of SITs to study the characteristics of the temporal and spatial distribution of Schistosoma japonicum and to assess the risk of infection provides methods for the control and prevention of schistosomiasis japonica has gradually become a hot topic in the field. The purpose of the present paper was to use RS and GIS technology to develop an efficient method of prediction and assessment of the risk of schistosomiasis japonica. We choose the Yueyang region, close to the east DongTing Lake (Hunan Province, China), as the study area, where a recent serious outbreak of schistosomiasis japonica took place. We monitored and evaluated the transmission risk of schistosomiasis japonica in the region using SITs. Water distribution data were extracted from RS images. The ground temperature, ground humidity and vegetation index were calculated based on RS images. Additionally, the density of oncomelania snails, which are the Schistosoma japonicum intermediate host, was calculated on the base of RS data and field measurements. The spatial distribution of oncomelania snails was explored using SITs in order to estimate the area surrounding the residents with transmission risk of schistosomiasis japonica. Our research result demonstrated: (1) the risk factors for the transmission of schistosomiasis japonica were closely related to the living environment of oncomelania snails. Key factors such as water distribution, ground temperature, ground humidity and vegetation index can be quickly obtained and calculated from RS images; (2) using GIS technology and a RS deduction technique along with statistical regression models, the density distribution model of oncomelania snails could be quickly built; (3) using SITs and analysis with overlaying population

  20. A Rapid Monitoring and Evaluation Method of Schistosomiasis Based on Spatial Information Technology

    PubMed Central

    Wang, Yong; Zhuang, Dafang

    2015-01-01

    Thanks to Spatial Information Technologies (SITs) such as Remote Sensing (RS) and Geographical Information System (GIS) that are being quickly developed and updated, SITs are being used more widely in the public health field. The use of SITs to study the characteristics of the temporal and spatial distribution of Schistosoma japonicum and to assess the risk of infection provides methods for the control and prevention of schistosomiasis japonica has gradually become a hot topic in the field. The purpose of the present paper was to use RS and GIS technology to develop an efficient method of prediction and assessment of the risk of schistosomiasis japonica. We choose the Yueyang region, close to the east DongTing Lake (Hunan Province, China), as the study area, where a recent serious outbreak of schistosomiasis japonica took place. We monitored and evaluated the transmission risk of schistosomiasis japonica in the region using SITs. Water distribution data were extracted from RS images. The ground temperature, ground humidity and vegetation index were calculated based on RS images. Additionally, the density of oncomelania snails, which are the Schistosoma japonicum intermediate host, was calculated on the base of RS data and field measurements. The spatial distribution of oncomelania snails was explored using SITs in order to estimate the area surrounding the residents with transmission risk of schistosomiasis japonica. Our research result demonstrated: (1) the risk factors for the transmission of schistosomiasis japonica were closely related to the living environment of oncomelania snails. Key factors such as water distribution, ground temperature, ground humidity and vegetation index can be quickly obtained and calculated from RS images; (2) using GIS technology and a RS deduction technique along with statistical regression models, the density distribution model of oncomelania snails could be quickly built; (3) using SITs and analysis with overlaying population

  1. Design of a Virtual Reality Navigational (VRN) experiment for assessment of egocentric spatial cognition.

    PubMed

    Byagowi, Ahmad; Moussavi, Zahra

    2012-01-01

    Virtual reality (VR) experiments are commonly used to assess human brain functions. We orient ourselves in an environment by computing precise self-to-object spatial relations (egocentric orientation) as well as object-to-object spatial relations (allocentric orientation). Egocentric orientation involves cues that depend on the position of the observer (i.e. left-right, front-behind), whereas allocentric orientation is maintained through the use of environmental features such as landmarks. As such, allocentric orientation involves short-term memory, whereas egocentric orientation does not. This paper presents a Virtual Reality Navigational (VRN) experiment specifically designed to assess egocentric spatial cognition. The design aimed to minimize the effect of spatial cues or landmarks for human navigation in a naturalistic VR environment. The VRN experiment designed for this study, called the Virtual House, is a symmetric three story cubic building, with 3 windows on each side on every floor, and one entrance on each side of the building. In each trial, a window is marked by a pseudo-random sequence as the objective. The marked window is shown to the participant from an outdoor view. The task is to reach the objective window using the shortest path through the building. The experiment entails 2 sets of 8 trials to cover all possibilities. The participants' performance error is measured by the difference between their traversed distance trajectory and the shortest natural distance (calculated using the VR engine), normalized by the shortest distance, in each trial. Fifty-two cognitively healthy adults participated in the study. The results show no learning effect during the 16 trails, implying that the experiment does not rely on short-term memory. Furthermore, the subjects' normalized performance error showed an almost linear increase with age, implying that egocentric spatial cognition ability declines with age. PMID:23367004

  2. Near or far? It depends on my impression: moral information and spatial behavior in virtual interactions.

    PubMed

    Iachini, Tina; Pagliaro, Stefano; Ruggiero, Gennaro

    2015-10-01

    Near body distance is a key component of action and social interaction. Recent research has shown that peripersonal space (reachability-distance for acting with objects) and interpersonal space (comfort-distance for interacting with people) share common mechanisms and reflect the social valence of stimuli. The social psychological literature has demonstrated that information about morality is crucial because it affects impression formation and the intention to approach-avoid others. Here we explore whether peripersonal/interpersonal spaces are modulated by moral information. Thirty-six participants interacted with male/female virtual confederates described by moral/immoral/neutral sentences. The modulation of body space was measured by reachability-distance and comfort-distance while participants stood still or walked toward virtual confederates. Results showed that distance expanded with immorally described confederates and contracted with morally described confederates. This pattern was present in both spaces, although it was stronger in comfort-distance. Consistent with an embodied cognition approach, the findings suggest that high-level socio-cognitive processes are linked to sensorimotor-spatial processes. PMID:26386781

  3. A left cerebral hemisphere's superiority in processing spatial-categorical information in a non-verbal semantic format.

    PubMed

    Suegami, Takashi; Laeng, Bruno

    2013-03-01

    It has been shown that the left and right cerebral hemispheres (LH and RH) respectively process qualitative or "categorical" spatial relations and metric or "coordinate" spatial relations. However, categorical spatial information could be thought as divided into two types: semantically-coded and visuospatially-coded categorical information. We examined whether a LH's advantage in processing semantic-categorical information is observed in a non-verbal format, and also whether semantic- and visuospatial-categorical processing are differentially lateralized. We manipulated the colors and positions of the standard traffic light sign as semantic- and visuospatial-categorical information respectively, and tested performance with the divided visual field method. In the semantic-categorical matching task, in which the participants judged if the semantic-categorical information of a successive cue and target was the same, a right visual field advantage was observed, suggesting a LH's preference for processing semantic-categorical information in a non-verbal format. In the visuospatial-categorical matching task, in which the participants judged if the visuospatial-categorical information of a successive cue and target was identical, a left visual field advantage was obtained. These results suggest that the processing of semantic-categorical information is lateralized in LH, and we discuss the dissociation between the two types of categorical information. PMID:23290044

  4. A novel semi-supervised hyperspectral image classification approach based on spatial neighborhood information and classifier combination

    NASA Astrophysics Data System (ADS)

    Tan, Kun; Hu, Jun; Li, Jun; Du, Peijun

    2015-07-01

    In the process of semi-supervised hyperspectral image classification, spatial neighborhood information of training samples is widely applied to solve the small sample size problem. However, the neighborhood information of unlabeled samples is usually ignored. In this paper, we propose a new algorithm for hyperspectral image semi-supervised classification in which the spatial neighborhood information is combined with classifier to enhance the classification ability in determining the class label of the selected unlabeled samples. There are two key points in this algorithm: (1) it is considered that the correct label should appear in the spatial neighborhood of unlabeled samples; (2) the combination of classifier can obtains better results. Two classifiers multinomial logistic regression (MLR) and k-nearest neighbor (KNN) are combined together in the above way to further improve the performance. The performance of the proposed approach was assessed with two real hyperspectral data sets, and the obtained results indicate that the proposed approach is effective for hyperspectral classification.

  5. The potential of spatial information in human biomonitoring by example of two German environmental epidemiology studies.

    PubMed

    Schmidt, Gunther; Pesch, Roland; Schröder, Winfried; Conrad, André; Kolossa-Gehring, Marike; Feigenspan, Stefan; Dobler, Lorenz; Wiesmüller, Gerhard A; Birke, Manfred; Utermann, Jens

    2011-08-01

    This study aimed at statistically investigating the association between the internal exposure of children and young adults to uranium (U) and epidemiologically relevant external determinants of exposure. The investigation was performed with data from two studies within the framework of the German health-related environmental monitoring program: The German Environmental Survey for Children (GerES IV) conducted by the Federal Environment Agency (Umweltbundesamt) with data on 1,780 children 3-14 years of age and their home environment and the German Environmental Specimen Bank (ESB, section: human specimens) with data on 2,253 students 20-29 years of age. Both studies provided data on the U levels in human urine for all probands. GerES IV furthermore provided an extensive environmental and demographic database on, e.g., U levels in drinking water. The data from GerES IV and ESB were linked by GIS to spatially relevant exposure information, including background values of U in stream sediments and in upper and lower soils, U levels in mosses and particulate matter in the lower atmosphere, precipitation and elevation as well as forest density. Bivariate correlation analysis and two decision tree models showed moderate but significant associations between U in human urine and U levels in drinking water, stream sediments and upper and lower soils. Future investigations considering additional epidemiologically relevant data sets may differentiate the results. Furthermore, the sample design of future environmental epidemiology studies should take the spatial evaluation of the data into greater account. PMID:21424229

  6. Mapping of groundwater potential zones across Ghana using remote sensing, geographic information systems, and spatial modeling.

    PubMed

    Gumma, Murali Krishna; Pavelic, Paul

    2013-04-01

    Groundwater development across much of sub-Saharan Africa is constrained by a lack of knowledge on the suitability of aquifers for borehole construction. The main objective of this study was to map groundwater potential at the country-scale for Ghana to identify locations for developing new supplies that could be used for a range of purposes. Groundwater potential zones were delineated using remote sensing and geographical information system (GIS) techniques drawing from a database that includes climate, geology, and satellite data. Subjective scores and weights were assigned to each of seven key spatial data layers and integrated to identify groundwater potential according to five categories ranging from very good to very poor derived from the total percentage score. From this analysis, areas of very good groundwater potential are estimated to cover 689,680 ha (2.9 % of the country), good potential 5,158,955 ha (21.6 %), moderate potential 10,898,140 ha (45.6 %), and poor/very poor potential 7,167,713 ha (30 %). The results were independently tested against borehole yield data (2,650 measurements) which conformed to the anticipated trend between groundwater potential and borehole yield. The satisfactory delineation of groundwater potential zones through spatial modeling suggests that groundwater development should first focus on areas of the highest potential. This study demonstrates the importance of remote sensing and GIS techniques in mapping groundwater potential at the country-scale and suggests that similar methods could be applied across other African countries and regions. PMID:22892995

  7. Including land use information for the spatial estimation of groundwater quality parameters - 1. Local estimation based on neighbourhood composition

    NASA Astrophysics Data System (ADS)

    Heißerer, T.; Haslauer, C. P.; Bárdossy, A.

    2016-04-01

    Most groundwater recharge comes from the infiltration of water through the land surface. Data analysis shows that solute concentrations at the water table vary between land use categories and depending on the land use composition within a certain neighbourhood. Driven by these observations, the goal of this paper is to estimate the solute distribution at a location depending on the composition of land use in the neighbourhood, even though land use information is categorical. This goal is achieved by mixing pure distributions of homogeneous land use according to their frequency of occurrence in the vicinity of, and their distance from an estimation location. These pure distributions are jointly inverted using a maximum likelihood-based approach. The neighbourhood size is optimized using cross-validation. Measurements below detection limit are included via their probabilities of non-exceedance. A solute-specific, spatially distributed measure of information content of the secondary information is presented. The method is applicable for many types of secondary information and can be used as drift for spatial estimation of the primary variable. This estimation is a local estimation and does not include larger scale spatial information. The information of measurements is included via the optimized concentration distributions for land use groups, not via a model of spatial dependence. The global estimation is described in the companion paper.

  8. The GIS weasel - An interface for the development of spatial information in modeling

    USGS Publications Warehouse

    Viger, R.J.; Markstrom, S.M.; Leavesley, G.H.

    2005-01-01

    The GIS Weasel is a map and Graphical User Interface (GUI) driven tool that has been developed as an aid to modelers in the delineation, characterization of geographic features, and their parameterization for use in distributed or lumped parameter physical process models. The interface does not require user expertise in geographic information systems (GIS). The user does need knowledge of how the model will use the output from the GIS Weasel. The GIS Weasel uses Workstation ArcInfo and its the Grid extension. The GIS Weasel will run on all platforms that Workstation ArcInfo runs (i.e. numerous flavors of Unix and Microsoft Windows).The GIS Weasel requires an input ArcInfo grid of some topographical description of the Area of Interest (AOI). This is normally a digital elevation model, but can be the surface of a ground water table or any other data that flow direction can be resolved from. The user may define the AOI as a custom drainage area based on an interactively specified watershed outlet point, or use a previously created map. The user is then able to use any combination of the GIS Weasel's tool set to create one or more maps for depicting different kinds of geographic features. Once the spatial feature maps have been prepared, then the GIS Weasel s many parameterization routines can be used to create descriptions of each element in each of the user s created maps. Over 200 parameterization routines currently exist, generating information about shape, area, and topological association with other features of the same or different maps, as well many types of information based on ancillary data layers such as soil and vegetation properties. These tools easily integrate other similarly formatted data sets.

  9. The geovisualisation window of the temporal and spatial variability for Volunteered Geographic Information activities

    NASA Astrophysics Data System (ADS)

    Medynska-Gulij, Beata; Myszczuk, Miłosz

    2012-11-01

    This study presents an attempt to design geographical visualisation tools that allow to tackle the immensity of spatial data provided by Volunteered Geographic Information (VGI), both in terms of temporal and spatial aspects. In accordance with the assumptions made at the conceptual stage, the final action was the implementation of the window entitled ‘Geovisualisation of the Panoramio.com Activities in District of Poznan 2011’ into the web browser. The concept has been based on a division of the geovisualisation window into three panels, of which the most important - in order to capture spatial variability - have statistical maps at the general level (dot map and choropleth map), while at the detailed level - a dot map on a topographic reference map or tourist map. For two ranges, temporal variability is presented by graphs, while a review of attributes of individual activities of the social website in question is set forward in the table panel. The element that visually interlinks all of the panels is the emphasised individual activity. Problemem podjetym w tych badaniach stało sie wykorzystanie metod z nurtu geograficznej wizualizacji do wskazania cech fenomenu VGI w zakresie zmiennosci czasowo-przestrzennej. Zgodnie z załozeniami poczynionymi w etapie koncepcyjnym finalnym działaniem stało sie zaimplementowanie do przegladarki internetowej okna pod tytułem: ”Geowizualizacja aktywnosci społecznosci Panoramio.com w powiecie poznanskim w 2011 roku”. Koncepcja została oparta na podziale okna geowizualizacji na trzy panele, z których najwazniejsze znaczenie dla uchwycenia zmiennosci przestrzennej na poziomie ogólnym ma kartogram, natomiast na poziomie szczegółowym mapa kropkowa wyswietlana na podkładzie mapy topograficznej lub turystycznej. Zmiennosc czasowa w dwóch zakresach prezentuja wykresy, a przeglad atrybutów poszczególnych aktywnosci prezentowanego portalu społecznosciowego zapewnia tabela. Elementem spajajacym wizualnie wszystkie

  10. Ambient visual information confers a context-specific, long-term benefit on memory for haptic scenes.

    PubMed

    Pasqualotto, Achille; Finucane, Ciara M; Newell, Fiona N

    2013-09-01

    We investigated the effects of indirect, ambient visual information on haptic spatial memory. Using touch only, participants first learned an array of objects arranged in a scene and were subsequently tested on their recognition of that scene which was always hidden from view. During haptic scene exploration, participants could either see the surrounding room or were blindfolded. We found a benefit in haptic memory performance only when ambient visual information was available in the early stages of the task but not when participants were initially blindfolded. Specifically, when ambient visual information was available a benefit on performance was found in a subsequent block of trials during which the participant was blindfolded (Experiment 1), and persisted over a delay of one week (Experiment 2). However, we found that the benefit for ambient visual information did not transfer to a novel environment (Experiment 3). In Experiment 4 we further investigated the nature of the visual information that improved haptic memory and found that geometric information about a surrounding (virtual) room rather than isolated object landmarks, facilitated haptic scene memory. Our results suggest that vision improves haptic memory for scenes by providing an environment-centred, allocentric reference frame for representing object location through touch. PMID:23764999

  11. Information Requirements for Integrating Spatially Discrete, Feature-Based Earth Observations

    NASA Astrophysics Data System (ADS)

    Horsburgh, J. S.; Aufdenkampe, A. K.; Lehnert, K. A.; Mayorga, E.; Hsu, L.; Song, L.; Zaslavsky, I.; Valentine, D. L.

    2014-12-01

    Several cyberinfrastructures have emerged for sharing observational data collected at densely sampled and/or highly instrumented field sites. These include the CUAHSI Hydrologic Information System (HIS), the Critical Zone Observatory Integrated Data Management System (CZOData), the Integrated Earth Data Applications (IEDA) and EarthChem system, and the Integrated Ocean Observing System (IOOS). These systems rely on standard data encodings and, in some cases, standard semantics for classes of geoscience data. Their focus is on sharing data on the Internet via web services in domain specific encodings or markup languages. While they have made progress in making data available, it still takes investigators significant effort to discover and access datasets from multiple repositories because of inconsistencies in the way domain systems describe, encode, and share data. Yet, there are many scenarios that require efficient integration of these data types across different domains. For example, understanding a soil profile's geochemical response to extreme weather events requires integration of hydrologic and atmospheric time series with geochemical data from soil samples collected over various depth intervals from soil cores or pits at different positions on a landscape. Integrated access to and analysis of data for such studies are hindered because common characteristics of data, including time, location, provenance, methods, and units are described differently within different systems. Integration requires syntactic and semantic translations that can be manual, error-prone, and lossy. We report information requirements identified as part of our work to define an information model for a broad class of earth science data - i.e., spatially-discrete, feature-based earth observations resulting from in-situ sensors and environmental samples. We sought to answer the question: "What information must accompany observational data for them to be archivable and discoverable within

  12. Spatially distributed storm runoff modeling using remote sensing and geographic information systems

    NASA Astrophysics Data System (ADS)

    Melesse, Assefa Mekonnen

    Advances in scientific knowledge and new techniques of remote sensing permit a better understanding of the physical land features governing hydrologic processes, and make possible efficient, large-scale hydrologic modeling. The need for land-cover and hydrologic response change detection at a larger scale and at times of the year when hydrologic studies are critical makes satellite imagery the most cost effective, efficient and reliable source of data. The use of a Geographic Information System (GIS) to store, manipulate and visualize these data, and ultimately to estimate runoff from watersheds, has gained increasing attention in recent years. In this work, remotely-sensed data and GIS tools were used to estimate the changes in land-cover, and to estimate runoff response, for three watersheds (Etonia, Econlockhatchee, and S-65A sub-basins) in Florida. Land-use information from Digital Orthophoto Quarter Quadrangles (DOQQ), Landsat Thematic Mapper (TM), and Enhanced Thematic Mapper Plus (ETM+) were analyzed for the years 1973, 1984, 1990, 1995, and 2000. Spatial distribution of land-cover was assessed over time. The corresponding infiltration excess runoff response of the study areas due to these changes was estimated using the United States Department of Agriculture, Natural Resources Conservation Service Curve Number (USDA-NRCS-CN) method. A Digital Elevation Model (DEM)-GIS technique was developed to predict stream response to runoff events based on the travel time from each grid cell to the watershed outlet. The method was tested on a representative watershed (Simms Creek) in the Etonia sub-basin. Simulated and observed runoff volume and hydrographs were compared for 17 storm events. Isolated storms, with volumes of not less than 12.75 mm (0.5 inch) were selected. This is the minimum amount of rainfall volume recommended for the NRCS-CN method. Results show that the model predicts the runoff response of the study area with an average efficiency of 57

  13. Condensation of earthquake location distributions: Optimal spatial information encoding and application to multifractal analysis of south Californian seismicity.

    PubMed

    Kamer, Yavor; Ouillon, Guy; Sornette, Didier; Wössner, Jochen

    2015-08-01

    We present the "condensation" method that exploits the heterogeneity of the probability distribution functions (PDFs) of event locations to improve the spatial information content of seismic catalogs. As its name indicates, the condensation method reduces the size of seismic catalogs while improving the access to the spatial information content of seismic catalogs. The PDFs of events are first ranked by decreasing location errors and then successively condensed onto better located and lower variance event PDFs. The obtained condensed catalog differs from the initial catalog by attributing different weights to each event, the set of weights providing an optimal spatial representation with respect to the spatially varying location capability of the seismic network. Synthetic tests on fractal distributions perturbed with realistic location errors show that condensation improves spatial information content of the original catalog, which is quantified by the likelihood gain per event. Applied to Southern California seismicity, the new condensed catalog highlights major mapped fault traces and reveals possible additional structures while reducing the catalog length by ∼25%. The condensation method allows us to account for location error information within a point based spatial analysis. We demonstrate this by comparing the multifractal properties of the condensed catalog locations with those of the original catalog. We evidence different spatial scaling regimes characterized by distinct multifractal spectra and separated by transition scales. We interpret the upper scale as to agree with the thickness of the brittle crust, while the lower scale (2.5 km) might depend on the relocation procedure. Accounting for these new results, the epidemic type aftershock model formulation suggests that, contrary to previous studies, large earthquakes dominate the earthquake triggering process. This implies that the limited capability of detecting small magnitude events cannot be used

  14. Condensation of earthquake location distributions: Optimal spatial information encoding and application to multifractal analysis of south Californian seismicity

    NASA Astrophysics Data System (ADS)

    Kamer, Yavor; Ouillon, Guy; Sornette, Didier; Wössner, Jochen

    2015-08-01

    We present the "condensation" method that exploits the heterogeneity of the probability distribution functions (PDFs) of event locations to improve the spatial information content of seismic catalogs. As its name indicates, the condensation method reduces the size of seismic catalogs while improving the access to the spatial information content of seismic catalogs. The PDFs of events are first ranked by decreasing location errors and then successively condensed onto better located and lower variance event PDFs. The obtained condensed catalog differs from the initial catalog by attributing different weights to each event, the set of weights providing an optimal spatial representation with respect to the spatially varying location capability of the seismic network. Synthetic tests on fractal distributions perturbed with realistic location errors show that condensation improves spatial information content of the original catalog, which is quantified by the likelihood gain per event. Applied to Southern California seismicity, the new condensed catalog highlights major mapped fault traces and reveals possible additional structures while reducing the catalog length by ˜25 % . The condensation method allows us to account for location error information within a point based spatial analysis. We demonstrate this by comparing the multifractal properties of the condensed catalog locations with those of the original catalog. We evidence different spatial scaling regimes characterized by distinct multifractal spectra and separated by transition scales. We interpret the upper scale as to agree with the thickness of the brittle crust, while the lower scale (2.5 km) might depend on the relocation procedure. Accounting for these new results, the epidemic type aftershock model formulation suggests that, contrary to previous studies, large earthquakes dominate the earthquake triggering process. This implies that the limited capability of detecting small magnitude events cannot be

  15. Dynamic visual information plays a critical role for spatial navigation in water but not on solid ground.

    PubMed

    Sautter, Chiara Sajidha; Cocchi, Luca; Schenk, Françoise

    2008-12-12

    In the Morris water maze (MWM) task, proprioceptive information is likely to have a poor accuracy due to movement inertia. Hence, in this condition, dynamic visual information providing information on linear and angular acceleration would play a critical role in spatial navigation. To investigate this assumption we compared rat's spatial performance in the MWM and in the homing hole board (HB) tasks using a 1.5 Hz stroboscopic illumination. In the MWM, rats trained in the stroboscopic condition needed more time than those trained in a continuous light condition to reach the hidden platform. They expressed also little accuracy during the probe trial. In the HB task, in contrast, place learning remained unaffected by the stroboscopic light condition. The deficit in the MWM was thus complete, affecting both escape latency and discrimination of the reinforced area, and was thus task specific. This dissociation confirms that dynamic visual information is crucial to spatial navigation in the MWM whereas spatial navigation on solid ground is mediated by a multisensory integration, and thus less dependent on visual information. PMID:18682262

  16. Hippocampal synaptic plasticity: role in spatial learning or the automatic recording of attended experience?

    PubMed Central

    Morris, R G; Frey, U

    1997-01-01

    Allocentric spatial learning can sometimes occur in one trial. The incorporation of information into a spatial representation may, therefore, obey a one-trial correlational learning rule rather than a multi-trial error-correcting rule. It has been suggested that physiological implementation of such a rule could be mediated by N-methyl-D-aspartate (NMDA) receptor-dependent long-term potentiation (LTP) in the hippocampus, as its induction obeys a correlational type of synaptic learning rule. Support for this idea came originally from the finding that intracerebral infusion of the NMDA antagonist AP5 impairs spatial learning, but studies summarized in the first part of this paper have called it into question. First, rats previously given experience of spatial learning in a watermaze can learn a new spatial reference memory task at a normal rate despite an appreciable NMDA receptor blockade. Second, the classical phenomenon of 'blocking' occurs in spatial learning. The latter finding implies that spatial learning can also be sensitive to an animal's expectations about reward and so depend on more than the detection of simple spatial correlations. In this paper a new hypothesis is proposed about the function of hippocampal LTP. This hypothesis retains the idea that LTP subserves rapid one-trial memory, but abandons the notion that it serves any specific role in the geometric aspects of spatial learning. It is suggested that LTP participates in the automatic recording of attended experience': a subsystem of episodic memory in which events are temporarily remembered in association with the contexts in which they occur. An automatic correlational form of synaptic plasticity is ideally suited to the online registration of context event associations. In support, it is reported that the ability of rats to remember the most recent place they have visited in a familiar environment is exquisitely sensitive to AP5 in a delay-dependent manner. Moreover, new studies of the lasting

  17. Incorporating bibliographic information into a spatial data query system for the Savannah River Site

    SciTech Connect

    Cowen, D.J.; Jensen, J.R.; MacCharles, C.V.; Holliday, W.N.; White, T.R.; Mackey, H.E. Jr.

    1995-01-01

    Over the past two years the Environmental Sciences Section of the Westinghouse Savannah River Company and the University of South Carolina have developed a full-featured spatial data query system for the Savannah River Site. This Environmental Data Atlas, which operates across multiple platforms, is designed to provide scientists with easy access to a wide range of GIS and remote sensing data resources. This paper describes the method that has been developed to extend the Environmental Data Atlas to incorporate bibliographical data. The bibliographic search function was determined by the scientists to be an extremely important enhancement that will enable them to utilize geographic keys to locate obscure references and databases. The method uses a Hot Link function to launch a parsing algorithm by pointing to geographic features. The parsing algorithm efficiently sorts through a list of references based on the keyword associated with the feature. The matched bibliographical entries are formatted into a text file that is displayed in a scrollable window. Any graphics associated with the actual reference can also be scanned and linked to an additional Hot Link. An additional parsing system was used to automatically create the bibliographical database from a comprehensive CD-ROM version of the Environmental Information Document prepared by the Environmental Sciences Section. This extensive digital reference represents a summary of much of the recent ecological information available on the site. The methods used in this system are directly linked to a commercially available software and provide a universal approach to establishing a geographically based document retrieval system.

  18. Morphological analysis of the primary center receiving spatial information transferred by the waggle dance of honeybees.

    PubMed

    Ai, Hiroyuki; Hagio, Hiromi

    2013-08-01

    The waggle dancers of honeybees encodes roughly the distance and direction to the food source as the duration of the waggle phase and the body angle during the waggle phase. It is believed that hive-mates detect airborne vibrations produced during the waggle phase to acquire distance information and simultaneously detect the body axis during the waggle phase to acquire direction information. It has been further proposed that the orientation of the body axis on the vertical comb is detected by neck hairs (NHs) on the prosternal organ. The afferents of the NHs project into the prothoracic and mesothoracic ganglia and the dorsal subesophageal ganglion (dSEG). This study demonstrates somatotopic organization within the dSEG of the central projections of the mechanosensory neurons of the NHs. The terminals of the NH afferents in dSEG are in close apposition to those of Johnston's organ (JO) afferents. The sensory axons of both terminate in a region posterior to the crossing of the ventral intermediate tract (VIT) and the maxillary dorsal commissures I and III (MxDCI, III) in the subesophageal ganglion. These features of the terminal areas of the NH and JO afferents are common to the worker, drone, and queen castes of honeybees. Analysis of the spatial relationship between the NH neurons and the morphologically and physiologically characterized vibration-sensitive interneurons DL-Int-1 and DL-Int-2 demonstrated that several branches of DL-Int-1 are in close proximity to the central projection of the mechanosensory neurons of the NHs in the dSEG. PMID:23297020

  19. Geodesic Information Flows: Spatially-Variant Graphs and Their Application to Segmentation and Fusion.

    PubMed

    Cardoso, M Jorge; Modat, Marc; Wolz, Robin; Melbourne, Andrew; Cash, David; Rueckert, Daniel; Ourselin, Sebastien

    2015-09-01

    Clinical annotations, such as voxel-wise binary or probabilistic tissue segmentations, structural parcellations, pathological regions-of-interest and anatomical landmarks are key to many clinical studies. However, due to the time consuming nature of manually generating these annotations, they tend to be scarce and limited to small subsets of data. This work explores a novel framework to propagate voxel-wise annotations between morphologically dissimilar images by diffusing and mapping the available examples through intermediate steps. A spatially-variant graph structure connecting morphologically similar subjects is introduced over a database of images, enabling the gradual diffusion of information to all the subjects, even in the presence of large-scale morphological variability. We illustrate the utility of the proposed framework on two example applications: brain parcellation using categorical labels and tissue segmentation using probabilistic features. The application of the proposed method to categorical label fusion showed highly statistically significant improvements when compared to state-of-the-art methodologies. Significant improvements were also observed when applying the proposed framework to probabilistic tissue segmentation of both synthetic and real data, mainly in the presence of large morphological variability. PMID:25879909

  20. Toward reliable retrieval of functional information of papillary dermis using spatially resolved diffuse reflectance spectroscopy.

    PubMed

    Chen, Yu-Wen; Guo, Jun-Yen; Tzeng, Shih-Yu; Chou, Ting-Chun; Lin, Ming-Jen; Huang, Lynn Ling-Huei; Yang, Chao-Chun; Hsu, Chao-Kai; Tseng, Sheng-Hao

    2016-02-01

    Spatially resolved diffuse reflectance spectroscopy (SRDRS) has been employed to quantify tissue optical properties and its interrogation volume is majorly controlled by the source-to-detector separations (SDSs). To noninvasively quantify properties of dermis, a SRDRS setup that includes SDS shorter than 1 mm is required. It will be demonstrated in this study that Monte Carlo simulations employing the Henyey-Greenstein phase function cannot always precisely predict experimentally measured diffuse reflectance at such short SDSs, and we speculated this could be caused by the non-negligible backward light scattering at short SDSs that cannot be properly modeled by the Henyey-Greenstein phase function. To accurately recover the optical properties and functional information of dermis using SRDRS, we proposed the use of the modified two-layer (MTL) geometry. Monte Carlo simulations and phantom experiment results revealed that the MTL probing geometry was capable of faithfully recovering the optical properties of upper dermis. The capability of the MTL geometry in probing the upper dermis properties was further verified through a swine study, and it was found that the measurement results were reasonably linked to histological findings. Finally, the MTL probe was utilized to study psoriatic lesions. Our results showed that the MTL probe was sensitive to the physiological condition of tissue volumes within the papillary dermis and could be used in studying the physiology of psoriasis. PMID:26977361

  1. Development of a prototype spatial information processing system for hydrologic research

    NASA Technical Reports Server (NTRS)

    Sircar, Jayanta K.

    1991-01-01

    Significant advances have been made in the last decade in the areas of Geographic Information Systems (GIS) and spatial analysis technology, both in hardware and software. Science user requirements are so problem specific that currently no single system can satisfy all of the needs. The work presented here forms part of a conceptual framework for an all-encompassing science-user workstation system. While definition and development of the system as a whole will take several years, it is intended that small scale projects such as the current work will address some of the more short term needs. Such projects can provide a quick mechanism to integrate tools into the workstation environment forming a larger, more complete hydrologic analysis platform. Described here are two components that are very important to the practical use of remote sensing and digital map data in hydrology. Described here is a graph-theoretic technique to rasterize elevation contour maps. Also described is a system to manipulate synthetic aperture radar (SAR) data files and extract soil moisture data.

  2. Spatial analysis of injury-related deaths in Dallas County using a geographic information system

    PubMed Central

    Abdalla, Adil; Gunst, Mark; Ghaemmaghami, Vafa; Gruszecki, Amy C.; Urban, Jill; Barber, Robert C.; Gentilello, Larry M.

    2012-01-01

    This study applied a geographic information system (GIS) to identify clusters of injury-related deaths (IRDs) within a large urban county (26 cities; population, 2.4 million). All deaths due to injuries in Dallas County (Texas) in 2005 (N = 670) were studied, including the geographic location of the injury event. Out of 26 cities in Dallas County, IRDs were reported in 19 cities. Geospatial data were obtained from the local governments and entered into the GIS. Standardized mortality ratios (SMR, with 95% CI) were calculated for each city and the county using national age-adjusted rates. Dallas County had significantly more deaths due to homicides (SMR, 1.76; 95% CI, 1.54–1.98) and IRDs as a result of gunshots (SMR, 1.23; 95% CI, 1.09–1.37) than the US national rate. However, this increase was restricted to a single city (the city of Dallas) within the county, while the rest of the 25 cities in the county experienced IRD rates that were either similar to or better than the national rate, or experienced no IRDs. GIS mapping was able to depict high-risk geographic “hot spots” for IRDs. In conclusion, GIS spatial analysis identified geographic clusters of IRDs, which were restricted to only one of 26 cities in the county. PMID:22754116

  3. Reconstructions of information in visual spatial working memory degrade with memory load.

    PubMed

    Sprague, Thomas C; Ester, Edward F; Serences, John T

    2014-09-22

    Working memory (WM) enables the maintenance and manipulation of information relevant to behavioral goals. Variability in WM ability is strongly correlated with IQ [1], and WM function is impaired in many neurological and psychiatric disorders [2, 3], suggesting that this system is a core component of higher cognition. WM storage is thought to be mediated by patterns of activity in neural populations selective for specific properties (e.g., color, orientation, location, and motion direction) of memoranda [4-13]. Accordingly, many models propose that differences in the amplitude of these population responses should be related to differences in memory performance [14, 15]. Here, we used functional magnetic resonance imaging and an image reconstruction technique based on a spatial encoding model [16] to visualize and quantify population-level memory representations supported by multivoxel patterns of activation within regions of occipital, parietal and frontal cortex while participants precisely remembered the location(s) of zero, one, or two small stimuli. We successfully reconstructed images containing representations of the remembered-but not forgotten-locations within regions of occipital, parietal, and frontal cortex using delay-period activation patterns. Critically, the amplitude of representations of remembered locations and behavioral performance both decreased with increasing memory load. These results suggest that differences in visual WM performance between memory load conditions are mediated by changes in the fidelity of large-scale population response profiles distributed across multiple areas of human cortex. PMID:25201683

  4. Toward reliable retrieval of functional information of papillary dermis using spatially resolved diffuse reflectance spectroscopy

    PubMed Central

    Chen, Yu-Wen; Guo, Jun-Yen; Tzeng, Shih-Yu; Chou, Ting-Chun; Lin, Ming-Jen; Huang, Lynn Ling-Huei; Yang, Chao-Chun; Hsu, Chao-Kai; Tseng, Sheng-Hao

    2016-01-01

    Spatially resolved diffuse reflectance spectroscopy (SRDRS) has been employed to quantify tissue optical properties and its interrogation volume is majorly controlled by the source-to-detector separations (SDSs). To noninvasively quantify properties of dermis, a SRDRS setup that includes SDS shorter than 1 mm is required. It will be demonstrated in this study that Monte Carlo simulations employing the Henyey-Greenstein phase function cannot always precisely predict experimentally measured diffuse reflectance at such short SDSs, and we speculated this could be caused by the non-negligible backward light scattering at short SDSs that cannot be properly modeled by the Henyey-Greenstein phase function. To accurately recover the optical properties and functional information of dermis using SRDRS, we proposed the use of the modified two-layer (MTL) geometry. Monte Carlo simulations and phantom experiment results revealed that the MTL probing geometry was capable of faithfully recovering the optical properties of upper dermis. The capability of the MTL geometry in probing the upper dermis properties was further verified through a swine study, and it was found that the measurement results were reasonably linked to histological findings. Finally, the MTL probe was utilized to study psoriatic lesions. Our results showed that the MTL probe was sensitive to the physiological condition of tissue volumes within the papillary dermis and could be used in studying the physiology of psoriasis. PMID:26977361

  5. [The "tunnel task": a method for examination of cognitive processes in spatial orientation performance].

    PubMed

    Schönebeck, B; Thanhäuser, J; Debus, G

    2001-01-01

    We report on the theoretical development and empirical testing of a new spatial cognition task, during which participants complete a tour through a virtual tunnel. Upon arrival they are asked to specify a "homing" vector by pointing an arrow towards the starting point of their virtual journey. Systematic experimental variations include number, length and sharpness of turns. Solving the task requires the development of a spatial representation, as alternative strategic cues (e.g., visual landmarks) are not available. Performance measures discriminate between general training effects and specific task variables. As an example, "side errors" indicate a loss of orientation and "position hits" reflect the accuracy of the spatial representation. Participants use either an egocentric or allocentric frame of reference. The task does not imply the use of egocentric vs. allocentric spatial co-ordinates, yet it allows for a reliable a-priori identification of individually preferred strategies. Our data indicate that the spatial representations formed by both groups are functionally equivalent. However, the groups differ with respect to specific patterns of orientation errors. PMID:11688148

  6. Considering the Spatial Layout Information of Bag of Features (BoF) Framework for Image Classification

    PubMed Central

    Mu, Guangyu; Liu, Ying; Wang, Limin

    2015-01-01

    The spatial pooling method such as spatial pyramid matching (SPM) is very crucial in the bag of features model used in image classification. SPM partitions the image into a set of regular grids and assumes that the spatial layout of all visual words obey the uniform distribution over these regular grids. However, in practice, we consider that different visual words should obey different spatial layout distributions. To improve SPM, we develop a novel spatial pooling method, namely spatial distribution pooling (SDP). The proposed SDP method uses an extension model of Gauss mixture model to estimate the spatial layout distributions of the visual vocabulary. For each visual word type, SDP can generate a set of flexible grids rather than the regular grids from the traditional SPM. Furthermore, we can compute the grid weights for visual word tokens according to their spatial coordinates. The experimental results demonstrate that SDP outperforms the traditional spatial pooling methods, and is competitive with the state-of-the-art classification accuracy on several challenging image datasets. PMID:26121038

  7. Viewing a Map versus Reading a Description of a Map: Modality-Specific Encoding of Spatial Information

    ERIC Educational Resources Information Center

    Tlauka, Michael; Keage, Hannah; Clark, C. Richard

    2005-01-01

    This study investigated whether brain neural activity that accompanied the processing of previously learned map information was influenced by the modality in which the spatial parameters of the maps were originally learned. Participants learned a map by either viewing it directly or by reading an equivalent verbal description. Following learning,…

  8. Geographic Information Systems and Libraries: Patrons, Maps, and Spatial Information. Papers presented at the Clinic on Library Applications of Data Processing (Champaign, Illinois, April 10-12, 1995).

    ERIC Educational Resources Information Center

    Smith, Linda C., Ed.; Gluck, Myke, Ed.

    This document assembles conference papers which focus on how electronic technologies are creating new ways of meeting user needs for spatial and cartographic information. Contents include: (1) "Mapping Technology in Transition" (Mark Monmonier); (2) "Cataloging Planetospatial Data in Digital Form: Old Wine, New Bottles--New Wine, Old Bottles"…

  9. Spatial information technologies for remote sensing today and tomorrow; Proceedings of the Ninth Pecora Symposium, Sioux Falls, SD, October 2-4, 1984

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Topics discussed at the symposium include hardware, geographic information system (GIS) implementation, processing remotely sensed data, spatial data structures, and NASA programs in remote sensing information systems. Attention is also given GIS applications, advanced techniques, artificial intelligence, graphics, spatial navigation, and classification. Papers are included on the design of computer software for geographic image processing, concepts for a global resource information system, algorithm development for spatial operators, and an application of expert systems technology to remotely sensed image analysis.

  10. Similarity in Spatial Origin of Information Facilitates Cue Competition and Interference

    ERIC Educational Resources Information Center

    Amundson, Jeffrey C.; Miller, Ralph R.

    2007-01-01

    Two lick suppression studies were conducted with water-deprived rats to investigate the influence of spatial similarity in cue interaction. Experiment 1 assessed the influence of similarity of the spatial origin of competing cues in a blocking procedure. Greater blocking was observed in the condition in which the auditory blocking cue and the…

  11. Numbers Are Associated with Different Types of Spatial Information Depending on the Task

    ERIC Educational Resources Information Center

    van Dijck, Jean-Philippe; Gevers, Wim; Fias, Wim

    2009-01-01

    In this study, we examined the nature of the spatial-numerical associations underlying the SNARC-effect by imposing a verbal or spatial working memory load during a parity judgment and a magnitude comparison task. The results showed a double dissociation between the type of working memory load and type of task. The SNARC-effect disappeared under…

  12. Brain and Behavior Processing of Contrast Information by Human Infants: Spatial and Temporal Changes.

    ERIC Educational Resources Information Center

    Karmel, Bernard Z.

    The purpose of this paper is to demonstrate that specific spatial and possibly temporal rates of change dominate early infants' looking, that these spatial and temporal events have meaningful and specific empirical correlates in neurophysiology as a function of age, and finally that neurophysiologically constrained models provide testable…

  13. Chronic Enhancement of CREB Activity in the Hippocampus Interferes with the Retrieval of Spatial Information

    ERIC Educational Resources Information Center

    Viosca, Jose; Malleret, Gael; Bourtchouladze, Rusiko; Benito, Eva; Vronskava, Svetlana; Kandel, Eric R.; Barco, Angel

    2009-01-01

    The activation of cAMP-responsive element-binding protein (CREB)-dependent gene expression is thought to be critical for the formation of different types of long-term memory. To explore the consequences of chronic enhancement of CREB function on spatial memory in mammals, we examined spatial navigation in bitransgenic mice that express in a…

  14. 6-Hydroxydopamine-Induced Dopamine Reductions in the Nucleus Accumbens, but not the Medial Prefrontal Cortex, Impair Cincinnati Water Maze Egocentric and Morris Water Maze Allocentric Navigation in Male Sprague-Dawley Rats.

    PubMed

    Braun, Amanda A; Amos-Kroohs, Robyn M; Gutierrez, Arnold; Lundgren, Kerstin H; Seroogy, Kim B; Vorhees, Charles V; Williams, Michael T

    2016-08-01

    The nucleus accumbens (Nacc) and medial prefrontal cortex (mPFC) receive dopaminergic innervation from the ventral tegmental area and are involved in learning. Male rats with 6-hydroxydopamine (6-OHDA)-induced dopaminergic and noradrenergic reductions in the Nacc or mPFC were tested for allocentric and egocentric learning to determine their role in these forms of neuroplasticity. mPFC dopaminergic and noradrenergic reductions did not result in changes to either type of learning or memory. Nacc dopaminergic and noradrenergic reductions resulted in allocentric learning and memory deficits in the Morris water maze (MWM) on acquisition, reversal, and probe trials. MWM cued performance was also affected, but straight-channel swim times and swim speed during hidden platform trials in the MWM were not affected. Nacc dopaminergic and noradrenergic reductions also impaired egocentric learning in the Cincinnati water maze (CWM). Nacc-lesioned animals tested in the CWM in an alternate path through the maze were not significantly affected. 6-OHDA injections in the Nacc resulted in 63 % dopamine and 62 % norepinephrine reductions in the Nacc and 23 % reductions in adjacent dorsal striatum. 6-OHDA injections in the mPFC resulted in 88 % reductions in dopamine and 59 % reductions in norepinephrine. Hence, Nacc dopamine and/or norepinephrine play a role in egocentric and allocentric learning and memory, while mPFC dopamine and norepinephrine do not. PMID:27003940

  15. Using a Novel Spatial Tool to Inform Invasive Species Early Detection and Rapid Response Efforts

    NASA Astrophysics Data System (ADS)

    Davidson, Alisha D.; Fusaro, Abigail J.; Kashian, Donna R.

    2015-07-01

    Management of invasive species has increasingly emphasized the importance of early detection and rapid response (EDRR) programs in limiting introductions, establishment, and impacts. These programs require an understanding of vector and species spatial dynamics to prioritize monitoring sites and efficiently allocate resources. Yet managers often lack the empirical data necessary to make these decisions. We developed an empirical mapping tool that can facilitate development of EDRR programs through identifying high-risk locations, particularly within the recreational boating vector. We demonstrated the utility of this tool in the Great Lakes watershed. We surveyed boaters to identify trips among water bodies and to quantify behaviors associated with high likelihood of species transfer (e.g., not removing organic materials from boat trailers) during that trip. We mapped water bodies with high-risk inbound and outbound boater movements using ArcGIS. We also tested for differences in high-risk behaviors based on demographic variables to understand risk differences among boater groups. Incorporation of boater behavior led to identification of additional high-risk water bodies compared to using the number of trips alone. Therefore, the number of trips itself may not fully reflect the likelihood of invasion. This tool can be broadly applied in other geographic contexts and with different taxa, and can be adjusted according to varying levels of information concerning the vector or species of interest. The methodology is straightforward and can be followed after a basic introduction to ArcGIS software. The visual nature of the mapping tool will facilitate site prioritization by managers and stakeholders from diverse backgrounds.

  16. Improvements in Virtual Sensors: Using Spatial Information to Estimate Remote Sensing Spectra

    NASA Technical Reports Server (NTRS)

    Oza, Nikunj C.; Srivastava, Ashok N.; Stroeve, Julienne

    2005-01-01

    Various instruments are used to create images of the Earth and other objects in the universe in a diverse set of wavelength bands with the aim of understanding natural phenomena. Sometimes these instruments are built in a phased approach, with additional measurement capabilities added in later phases. In other cases, technology may mature to the point that the instrument offers new measurement capabilities that were not planned in the original design of the instrument. In still other cases, high resolution spectral measurements may be too costly to perform on a large sample and therefore lower resolution spectral instruments are used to take the majority of measurements. Many applied science questions that are relevant to the earth science remote sensing community require analysis of enormous amounts of data that were generated by instruments with disparate measurement capabilities. In past work [1], we addressed this problem using Virtual Sensors: a method that uses models trained on spectrally rich (high spectral resolution) data to "fill in" unmeasured spectral channels in spectrally poor (low spectral resolution) data. We demonstrated this method by using models trained on the high spectral resolution Terra MODIS instrument to estimate what the equivalent of the MODIS 1.6 micron channel would be for the NOAA AVHRR2 instrument. The scientific motivation for the simulation of the 1.6 micron channel is to improve the ability of the AVHRR2 sensor to detect clouds over snow and ice. This work contains preliminary experiments demonstrating that the use of spatial information can improve our ability to estimate these spectra.

  17. Technical note: The use of geographical information systems software for the spatial analysis of bone microstructure.

    PubMed

    Rose, David C; Agnew, Amanda M; Gocha, Timothy P; Stout, Sam D; Field, Julie S

    2012-08-01

    Geographic information systems (GIS) software is typically used for analyzing geographically distributed data, allowing users to annotate points or areas on a map and attach data for spatial analyses. While traditional GIS-based research involves geo-referenced data (points tied to geographic locations), the use of this technology has other constructive applications for physical anthropologists. The use of GIS software for the study of bone histology offers a novel opportunity to analyze the distribution of bone nano- and microstructures, relative to macrostructure and in comparison to other variables of interest, such as biomechanical loading history. This approach allows for the examination of characteristics of single histological features while considering their role at the macroscopic level. Such research has immediate promise in examining the load history of bone by surveying the functional relationship between collagen fiber orientation (CFO) and strain mode. The diversity of GIS applications that may be utilized in bone histology research is just beginning to be explored. The goal of this study is to introduce a reliable methodology for such investigation and our objective is to quantify the heterogeneity of bone microstructure over an entire cross-section of bone using ArcGIS v 9.3 (ESRI). This was accomplished by identifying the distribution of remodeling units in a human metatarsal relative to bending axes. One biomechanical hypothesis suggests that CFO, manifested by patterns of birefringence, is indicative of mode of strain during formation. This study demonstrates that GIS can be used to investigate, describe, and compare such patterns through histological mapping. PMID:22700420

  18. Monitoring the Environment using High-Spatial Resolution Remote Sensing: Contribution to Health Information Systems

    NASA Astrophysics Data System (ADS)

    Tourre, Y. M.; Lacaux, J.

    2007-12-01

    Presence (density) of mosquitoes linked to Rift Valley Fever (RVF) epidemics in the Ferlo (Senegal) is evaluated by monitoring the environment from space. Using five SPOT-5 high-resolution images (~10m spatial resolution, on August 17th, 2006) a meridional transect of 290 x 60 km2 is analyzed for the first time. Four major ecozones are thus identified: Senegal River valley; sandy Ferlo; sandy-clayey Ferlo; and steppe/cultivated areas, from north to south, respectively. An integrated/multidisciplinary approach using remote-sensing leads to a composited Zones Potentially Occupied by Mosquitoes (or ZPOMs, with extrema). It is found that at the peak of the rainy season, the area occupied by ponds is of 12,817 ha ± 10% (i.e., ~ 0.8 % of the transect) with a mean ZPOM 17 times larger i.e.: 212,813 ha ± 10 % (or ~14 % of the transect). ZPOMs characteristics (minimum and maximum) at the ecozones levels with different hydrological mechanisms, are presented. Ponds and ZPOMs inter-annual variabilities and RVF risks, are subsequently highlighted by comparing statistics in the so-called Barkedji zone (sandy-clayey Ferlo with a hydrofossil riverbed), for the very humid year of 2003, and the near normal rainfall year of 2006. It is shown that at the end of August 2003/2006, ponds (ZPOMs) areas, were already ~22 (~5) times larger. The key roles played by isolated ponds for animals' exposure to RVF risks are thus identified. These results highlight the importance of monitoring the changing environment when linkages with public health exist. The ZPOM approach is to be adapted for other vector-borne diseases such as malaria, dengue fever, in different places of the world. Results are meant to be included into Health Information Systems (HIS) on an operational basis, in order to minimize socio-economical impacts from epidemics.

  19. The hippocampus and spatial constraints on mental imagery

    PubMed Central

    Bird, Chris M.; Bisby, James A.; Burgess, Neil

    2012-01-01

    We review a model of imagery and memory retrieval based on allocentric spatial representation by place cells and boundary vector cells (BVCs) in the medial temporal lobe, and their translation into egocentric images in retrosplenial and parietal areas. In this model, the activity of place cells constrain the contents of imagery and retrieval to be coherent and consistent with the subject occupying a single location, while the activity of head-direction cells along Papez's circuit determine the viewpoint direction for which the egocentric image is generated. An extension of this model is discussed in which a role for grid cells in dynamic updating of representations (mental navigation) is included. We also discuss the extension of this model to implement a version of the dual representation theory of post-traumatic stress disorder (PTSD) in which PTSD arises from an imbalance between weak allocentric hippocampal-mediated contextual representations and strong affective/sensory representations. The implications of these models for behavioral, neuropsychological, and neuroimaging data in humans are explored. PMID:22629242

  20. 76 FR 44354 - Agency Information Collection Activities: Comment Request for National Spatial Data...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-25

    ... Infrastructure, Cooperative Agreements Program (NSDI CAP) AGENCY: United States Geological Survey (USGS... (IC) for the National Spatial Data Infrastructure, Cooperative Agreements Program (NSDI CAP). This... Respondents are submitting proposals to acquire funding for projects to help build the...

  1. Mapping the physical location of Telecenter using the geospatial information systems: A requirement of spatial digital mapping

    NASA Astrophysics Data System (ADS)

    Bohari, Abdul Manaf; Hin, Cheng Wei; Fuad, Nurwahida

    2016-08-01

    Recently, a study of Telecenter lifetime value is vital to academician, government and non-profit organization where Telecenter has great contribute to the nation development of rural community. Telecenter as important location of enhance the relationship of socio-economic, where placed all non-profit activity into single location platform. Consistently, previous studies mentioned Telecenter have significance contribution toward the nation, however, research and knowledge still lacking regarding the location factors that affecting the Telecenter specifically on spatial aspects of physical location environment. This research aimed to understand the requirement of spatial digital mapping the physical location of Telecenter, according to location of user and it environment, by using the geospatial information systems references, as called grid coordinate systems. The suggestion and implications of this study are briefly explored where spatial location factor plays important role in determine the lifetime value of Telecenter.

  2. Effects of age on spatial information processing: relationship to senescent changes in brain noradrenergic and opioid systems

    SciTech Connect

    Rapp, P.R.

    1985-01-01

    A major focus in current research on aging is the identification of senescent changes in cognitive function in laboratory animals. This literature indicates that the processing of spatial information may be particularly impaired during senescence. The degree to which nonspecific factors (eg. sensory of motor deficits) contribute to behavioral impairments in aging, however, remains largely uninvestigated. In addition, few studies have attempted to identify senescent changes in brain structure and function which might underlie the behavioral manifestations of aging. In the behavioral experiments reported here, the authors tested young, middle-age, and senescent rates in several versions of a spatial memory task, the Morris water maze. The results of these investigations demonstrate that aged rats are significantly impaired in the Morris task compared to young or middle-age animals. In addition, these studies indicate that age-related deficits in the water maze reflect a specific dysfunction in the ability of older animals to effectively process spatial information rather than a senescent decline in sensory or motor functions. Using the subjects from the behavioral studies, additional investigations assessed whether age-dependent changes in neurochemical and neuroanatomical systems which are known to mediate spatial learning in young animals were related to the behavioral deficits exhibited by aged rats. The results of these studies demonstrate that a portion of senescent animals exhibit significant increases in lateral septal /sup 3/H-desmethylimipramine binding and decrease in /sup 3/H-naloxone binding in this same region as assessed by quantitative in vitro autoradiography.

  3. Spatial release from energetic and informational masking in a divided speech identification task.

    PubMed

    Ihlefeld, Antje; Shinn-Cunningham, Barbara

    2008-06-01

    When listening selectively to one talker in a two-talker environment, performance generally improves with spatial separation of the sources. The current study explores the role of spatial separation in divided listening, when listeners reported both of two simultaneous messages processed to have little spectral overlap (limiting "energetic masking" between the messages). One message was presented at a fixed level, while the other message level varied from equal to 40 dB less than that of the fixed-level message. Results demonstrate that spatial separation of the competing messages improved divided-listening performance. Most errors occurred because listeners failed to report the content of the less-intense talker. Moreover, performance generally improved as the broadband energy ratio of the variable-level to the fixed-level talker increased. The error patterns suggest that spatial separation improves the intelligibility of the less-intense talker by improving the ability to (1) hear portions of the signal that would otherwise be masked, (2) segregate the two talkers properly into separate perceptual streams, and (3) selectively focus attention on the less-intense talker. Spatial configuration did not noticeably affect the ability to report the more-intense talker, suggesting that it was processed differently than the less-intense talker, which was actively attended. PMID:18537389

  4. The effect of TOMM40 on spatial navigation in amnestic mild cognitive impairment.

    PubMed

    Laczó, Jan; Andel, Ross; Vyhnalek, Martin; Matoska, Vaclav; Kaplan, Vojtech; Nedelska, Zuzana; Lerch, Ondrej; Gazova, Ivana; Moffat, Scott D; Hort, Jakub

    2015-06-01

    The very long (VL) poly-T variant at rs10524523 ("523") of the TOMM40 gene may hasten the onset of late-onset Alzheimer's disease (LOAD) and induce more profound cognitive impairment compared with the short (S) poly-T variant. We examined the influence of TOMM40 "523" polymorphism on spatial navigation and its brain structural correlates. Participants were apolipoprotein E (APOE) ε3/ε3 homozygotes with amnestic mild cognitive impairment (aMCI). The homozygotes were chosen because APOE ε3/ε3 variant is considered "neutral" with respect to LOAD risk. The participants were stratified according to poly-T length polymorphisms at "523" into homozygous for S (S/S; n = 16), homozygous for VL (VL/VL; n = 15) TOMM40 poly-T variant, and heterozygous (S/VL; n = 28) groups. Neuropsychological examination and testing in real-space human analog of the Morris Water Maze were administered. Both self-centered (egocentric) and world-centered (allocentric) spatial navigation was assessed. Brain magnetic resonance imaging scans were analyzed using FreeSurfer software. The S/S group, although similar to S/VL and VL/VL groups in demographic and neuropsychological profiles, performed better on allocentric navigation (p ≤ 0.004) and allocentric delayed recall (p ≤ 0.014), but not on egocentric navigation. Both S/VL and VL/VL groups had thinner right entorhinal cortex (p ≤ 0.043) than the S/S group, whereas only the VL/VL group had thinner left entorhinal cortex (p = 0.043) and left posterior cingulate cortex (p = 0.024) than the S/S group. In conclusion, TOMM40 "523" VL variants are related to impairment in allocentric spatial navigation and reduced cortical thickness of specific brain regions among aMCI individuals with (LOAD neutral) APOE ε3/ε3 genotype. This may reflect a specific role of TOMM40 "523" in the pathogenesis of LOAD. PMID:25862420

  5. Functional equivalence of verbal and spatial information in serial short-term memory.

    PubMed

    Jones, D; Farrand, P; Stuart, G; Morris, N

    1995-07-01

    Performance on a test of serial memory for the spatial position of a sequence of dots showed similarities to typical results from the serial recall of verbal material: a marked increase in error with increasing list length, a modest rise in error as retention interval increased, and bow-shaped serial position curves. This task was susceptible to interference from both a spatial task (rote tapping) and a verbal task (mouthed articulatory suppression) and also from the presence of irrelevant speech. Effects were comparable to those found with a serial verbal task that was generally similar in demand characteristics to the spatial task. As a generalization, disruption of the serial recall of visuospatial material was more marked if the interference conditions involved a changing sequence of actions or materials, but not if a single event (tap, mouthed utterance, or sound) was repeated. PMID:7673864

  6. Spatial neglect clinical and neuroscience review: a wealth of information on the poverty of attention

    PubMed Central

    Adair, John C.; Barrett, Anna M.

    2010-01-01

    Hemispatial neglect (HSN) is a frequent, conspicuous neurobehavioral accompaniment of brain injury. Patients with HSN share several superficial similarities, leading earlier clinical neuroscientists to view neglect as a unitary condition associated with brain structures that mediate relatively discrete spatial cognitive mechanisms. Over the last two decades, research largely deconstructed the neglect syndrome, revealing a remarkable heterogeneity of behaviors and providing insight into multiple component processes, both spatial and nonspatial, that contribute to hemispatial neglect. This review surveys visual HSN, presenting first the means for detection and diagnosis in its manifold variations. We summarize cognitive operations relevant to spatial attention and evidence for their role in neglect behaviors and then briefly consider neural systems that may subserve the component processes. Finally, we propose several methods for rehabilitating HSN, including the challenges facing remediation of such a heterogeneous cognitive disorder. PMID:18990119

  7. Urban spatial information services based on service-oriented grid architecture

    NASA Astrophysics Data System (ADS)

    Mou, Naixia; Zhang, Lingxian; Ai, Bo; Liu, Wenbao

    2007-11-01

    The need of spatial data sharing is increasing with the rapid urban expansion. However, the methods for spatial data sharing have not been well developed so far. In this paper, we establish a tri-layer geoinformation service framework using the Grid, SOA and web service. First, we integrated three modes that use geoinformation, which were: 1) the simple mode of viewing spatial data, 2) the analysis mode of querying and analyzing geoinformation, and 3) the peer mode of complex computing capabilities. Second, we designed a reasonable, flexible architecture of geoinformation service according to the three modes and expatiated the principles of each part. Then we argued that the middleware should be context-sensitive to provide intelligent services. We also discussed how to decide context detailedly and illustrated the principles of context-sensitive middleware. We found that the service-oriented grid architecture could realize data sharing and service more smoothly and accessibly.

  8. From Capture to Inhibition: How does Irrelevant Information Influence Visual Search? Evidence from a Spatial Cuing Paradigm

    PubMed Central

    Mertes, Christine; Wascher, Edmund; Schneider, Daniel

    2016-01-01

    Even though information is spatially and temporally irrelevant, it can influence the processing of subsequent information. The present study used a spatial cuing paradigm to investigate the origins of this persisting influence by means of event-related potentials (ERPs) of the EEG. An irrelevant color cue that was either contingent (color search) or non-contingent (shape search) on attentional sets was presented prior to a target array with different stimulus-onset asynchronies (SOA; 200, 400, 800 ms). Behavioral results indicated that color cues captured attention only when they shared target-defining properties. These same-location effects persisted over time but were pronounced when cue and target array were presented in close succession. N2 posterior contralateral (N2pc) showed that the color cue generally drew attention, but was strongest in the contingent condition. A subsequently emerging contralateral posterior positivity referred to the irrelevant cue (i.e., distractor positivity, Pd) was unaffected by the attentional set and therefore interpreted as an inhibitory process required to enable a re-direction of the attentional focus. Contralateral delay activity (CDA) was only observable in the contingent condition, indicating the transfer of spatial information into working memory and thus providing an explanation for the same-location effect for longer SOAs. Inhibition of this irrelevant information was reflected by a second contralateral positivity triggered through target presentation. The results suggest that distracting information is actively maintained when it resembles a sought-after object. However, two independent attentional processes are at work to compensate for attentional distraction: the timely inhibition of attentional capture and the active inhibition of mental representation of irrelevant information. PMID:27242493

  9. From Capture to Inhibition: How does Irrelevant Information Influence Visual Search? Evidence from a Spatial Cuing Paradigm.

    PubMed

    Mertes, Christine; Wascher, Edmund; Schneider, Daniel

    2016-01-01

    Even though information is spatially and temporally irrelevant, it can influence the processing of subsequent information. The present study used a spatial cuing paradigm to investigate the origins of this persisting influence by means of event-related potentials (ERPs) of the EEG. An irrelevant color cue that was either contingent (color search) or non-contingent (shape search) on attentional sets was presented prior to a target array with different stimulus-onset asynchronies (SOA; 200, 400, 800 ms). Behavioral results indicated that color cues captured attention only when they shared target-defining properties. These same-location effects persisted over time but were pronounced when cue and target array were presented in close succession. N2 posterior contralateral (N2pc) showed that the color cue generally drew attention, but was strongest in the contingent condition. A subsequently emerging contralateral posterior positivity referred to the irrelevant cue (i.e., distractor positivity, Pd) was unaffected by the attentional set and therefore interpreted as an inhibitory process required to enable a re-direction of the attentional focus. Contralateral delay activity (CDA) was only observable in the contingent condition, indicating the transfer of spatial information into working memory and thus providing an explanation for the same-location effect for longer SOAs. Inhibition of this irrelevant information was reflected by a second contralateral positivity triggered through target presentation. The results suggest that distracting information is actively maintained when it resembles a sought-after object. However, two independent attentional processes are at work to compensate for attentional distraction: the timely inhibition of attentional capture and the active inhibition of mental representation of irrelevant information. PMID:27242493

  10. GeoCREV: veterinary geographical information system and the development of a practical sub-national spatial data infrastructure.

    PubMed

    Ferrè, Nicola; Mulatti, Paolo; Mazzucato, Matteo; Lorenzetto, Monica; Trolese, Matteo; Pandolfo, Dario; Vio, Piero; Sitta, Guido; Marangon, Stefano

    2011-05-01

    This paper illustrates and discusses the key issues of the geographical information system (GIS) developed by the Unit of Veterinary Epidemiology of the Veneto region (CREV), defined according to user needs, spatial data (availability, accessibility and applicability), development, technical aspects, inter-institutional relationships, constraints and policies. GeoCREV, the support system for decision-making, was designed to integrate geographic information and veterinary laboratory data with the main aim to develop a sub-national, spatial data infrastructure (SDI) for the veterinary services of the Veneto region in north-eastern Italy. Its implementation required (i) collection of data and information; (ii) building a geodatabase; and (iii) development of a WebGIS application. Tools for the management, collection, validation and dissemination of the results (public access and limited access) were developed. The modular concept facilitates the updating and development of the system according to user needs and data availability. The GIS management practices that were followed to develop the system are outlined, followed by a detailed discussion of the key elements of the GIS implementation process (data model, technical aspects, inter-institutional relationship, user dimension and institutional framework). Problems encountered in organising the non-spatial data and the future work directions are also described. PMID:21590678

  11. Exploring the potentials of volunteered geographic Information as a source for spatial data acquisition

    NASA Astrophysics Data System (ADS)

    Ariffin, Izyana; Solemon, Badariah; Anwar, Rina Md; Din, Marina Md; Nashrah Azmi, Nor

    2014-06-01

    The advancement of technologies nowadays enables participation by nonprofessionals, known as volunteers to participate in producing, sharing and consuming geographic information. Such information, termed as volunteered geographic Information (VGI) has created a new approach of gathering geographic information. This paper discusses the traditional way of acquiring geographic information and potentials of VGI as an information source in GIS applications. We also review four commonly cited applications which rely on volunteers for their geographic information based on five criteria; the geometry type available in the applications, availability of user profile, average number of attributes used in the applications, data type of the information (raster or vector) and the domain the application belongs to. This review serves as a preliminarv study in designing a GIS application used for asset management which aims at exploiting volunteers to produce geographic information related to assets.

  12. Anticipatory control and spatial cognition in locomotion and navigation through typical development and in cerebral palsy.

    PubMed

    Belmonti, Vittorio; Cioni, Giovanni; Berthoz, Alain

    2016-03-01

    Behavioural evidence, summarized in this narrative review, supports a developmental model of locomotor control based on increasing neural integration of spatial reference frames. Two consistent adult locomotor behaviours are head stabilization and head anticipation: the head is stabilized to gravity and leads walking direction. This cephalocaudal orienting organization aligns gaze and vestibula with a reference frame centred on the upcoming walking direction, allowing anticipatory control on body kinematics, but is not fully developed until adolescence. Walking trajectories and those of hand movements share many aspects, including power laws coupling velocity to curvature, and minimized spatial variability. In fact, the adult brain can code trajectory geometry in an allocentric reference frame, irrespective of the end effector, regulating body kinematics thereafter. Locomotor trajectory formation, like head anticipation, matures in early adolescence, indicating common neurocomputational substrates. These late-developing control mechanisms can be distinguished from biomechanical problems in children with cerebral palsy (CP). Children's performance on a novel navigation test, the Magic Carpet, indicates that typical navigation development consists of the increasing integration of egocentric and allocentric reference frames. In CP, right-brain impairment seems to reduce navigation performance due to a maladaptive left-brain sequential egocentric strategy. Spatial integration should be considered more in rehabilitation. PMID:27027604

  13. Perirhinal Cortex Lesions Produce Retrograde Amnesia for Spatial Information in Rats: Consolidation or Retrieval?

    ERIC Educational Resources Information Center

    Ramos, Juan M. J.

    2008-01-01

    Several lines of evidence in humans and experimental animals suggest that the hippocampus is critical for the formation and retrieval of spatial memory. However, although the hippocampus is reciprocally connected to adjacent cortices within the medial temporal lobe and they, in turn, are connected to the neocortex, little is known regarding the…

  14. Nitrogen, ecosystem services and environmental justice: How can a spatial valuation approach inform responsible nutrient management?

    EPA Science Inventory

    Spatially-explicit ecosystem service valuation (ESV) allows for the identification of the location and magnitude of services provided by natural ecosystems along with an economic measure of their value based upon benefit transfer. While this provides an important function in term...

  15. Characterizing the multi–scale spatial structure of remotely sensed evapotranspiration with information theory

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A more thorough understanding of the multi-scale spatial structure of land surface heterogeneity will enhance understanding of the relationships and feedbacks between land surface conditions,mass and energy exchanges between the surface and the atmosphere, and regional meteorological and climatologi...

  16. Sound-Diffracting Flap in the Ear of a Bat Generates Spatial Information

    NASA Astrophysics Data System (ADS)

    Müller, Rolf; Lu, Hongwang; Buck, John R.

    2008-03-01

    Sound diffraction by the mammalian ear generates source-direction information. We have obtained an immediate quantification of this information from numerical predictions. We demonstrate the power of our approach by showing that a small flap in a bat’s pinna generates useful information over a large set of directions in a central band of frequencies: presence of the flap more than doubled the solid angle with direction information above a given threshold. From the workings of the employed information measure, the Cramér-Rao lower bound, we can explain how physical shape is linked to sensory information via a strong sidelobe with frequency-dependent orientation in the directivity pattern. This method could be applied to any other mammal species with pinnae to quantify the relative importance of pinna structures’ contributions to directional information and to facilitate interspecific comparisons of pinna directivity patterns.

  17. Remote sensing, geographical information systems, and spatial modeling for analyzing public transit services

    NASA Astrophysics Data System (ADS)

    Wu, Changshan

    Public transit service is a promising transportation mode because of its potential to address urban sustainability. Current ridership of public transit, however, is very low in most urban regions, particularly those in the United States. This woeful transit ridership can be attributed to many factors, among which poor service quality is key. Given this, there is a need for transit planning and analysis to improve service quality. Traditionally, spatially aggregate data are utilized in transit analysis and planning. Examples include data associated with the census, zip codes, states, etc. Few studies, however, address the influences of spatially aggregate data on transit planning results. In this research, previous studies in transit planning that use spatially aggregate data are reviewed. Next, problems associated with the utilization of aggregate data, the so-called modifiable areal unit problem (MAUP), are detailed and the need for fine resolution data to support public transit planning is argued. Fine resolution data is generated using intelligent interpolation techniques with the help of remote sensing imagery. In particular, impervious surface fraction, an important socio-economic indicator, is estimated through a fully constrained linear spectral mixture model using Landsat Enhanced Thematic Mapper Plus (ETM+) data within the metropolitan area of Columbus, Ohio in the United States. Four endmembers, low albedo, high albedo, vegetation, and soil are selected to model heterogeneous urban land cover. Impervious surface fraction is estimated by analyzing low and high albedo endmembers. With the derived impervious surface fraction, three spatial interpolation methods, spatial regression, dasymetric mapping, and cokriging, are developed to interpolate detailed population density. Results suggest that cokriging applied to impervious surface is a better alternative for estimating fine resolution population density. With the derived fine resolution data, a multiple

  18. Hippocampal Synaptic Expansion Induced by Spatial Experience in Rats Correlates with Improved Information Processing in the Hippocampus

    PubMed Central

    Carasatorre, Mariana; Ochoa-Alvarez, Adrian; Velázquez-Campos, Giovanna; Lozano-Flores, Carlos; Díaz-Cintra, Sofía Y.; Ramírez-Amaya, Víctor

    2015-01-01

    Spatial water maze (WM) overtraining induces hippocampal mossy fiber (MF) expansion, and it has been suggested that spatial pattern separation depends on the MF pathway. We hypothesized that WM experience inducing MF expansion in rats would improve spatial pattern separation in the hippocampal network. We first tested this by using the the delayed non-matching to place task (DNMP), in animals that had been previously trained on the water maze (WM) and found that these animals, as well as animals treated as swim controls (SC), performed better than home cage control animals the DNMP task. The “catFISH” imaging method provided neurophysiological evidence that hippocampal pattern separation improved in animals treated as SC, and this improvement was even clearer in animals that experienced the WM training. Moreover, these behavioral treatments also enhance network reliability and improve partial pattern separation in CA1 and pattern completion in CA3. By measuring the area occupied by synaptophysin staining in both the stratum oriens and the stratun lucidum of the distal CA3, we found evidence of structural synaptic plasticity that likely includes MF expansion. Finally, the measures of hippocampal network coding obtained with catFISH correlate significantly with the increased density of synaptophysin staining, strongly suggesting that structural synaptic plasticity in the hippocampus induced by the WM and SC experience is related to the improvement of spatial information processing in the hippocampus. PMID:26244549

  19. Enhancement of Spatial Ability in Girls in a Single-Sex Environment through Spatial Experience and the Impact on Information Seeking

    ERIC Educational Resources Information Center

    Swarlis, Linda L.

    2008-01-01

    The test scores of spatial ability for women lag behind those of men in many spatial tests. On the Mental Rotations Test (MRT), a significant gender gap has existed for over 20 years and continues to exist. High spatial ability has been linked to efficiencies in typical computing tasks including Web and database searching, text editing, and…

  20. Background updating and shadow detection based on spatial, color, and texture information of detected objects

    NASA Astrophysics Data System (ADS)

    Hamad, Ahmed Mahmoud; Tsumura, Norimichi

    2012-05-01

    Background model updating is a vital process for any background subtraction technique. This paper presents an updating mechanism that can be applied efficiently to any background subtraction technique. This updating mechanism exploits the color and spatial features to characterize each detected object. Spatial and color features are used to classify each detected object as a moving background object, a ghost, or a real moving object. The starting position of each detected object is the cue for updating background images. In addition, this paper presents a hybrid scheme to detect and remove cast shadows based on texture and color features. The robustness of the proposed method and its effectiveness in overcoming challenging problems such as gradual and sudden illumination changes, ghost appearance, non-stationary background objects, the stability of moving objects most of the time, and cast shadows are verified quantitatively and qualitatively.

  1. Locating Sensors for Detecting Source-to-Target Patterns of Special Nuclear Material Smuggling: A Spatial Information Theoretic Approach

    PubMed Central

    Przybyla, Jay; Taylor, Jeffrey; Zhou, Xuesong

    2010-01-01

    In this paper, a spatial information-theoretic model is proposed to locate sensors for detecting source-to-target patterns of special nuclear material (SNM) smuggling. In order to ship the nuclear materials from a source location with SNM production to a target city, the smugglers must employ global and domestic logistics systems. This paper focuses on locating a limited set of fixed and mobile radiation sensors in a transportation network, with the intent to maximize the expected information gain and minimize the estimation error for the subsequent nuclear material detection stage. A Kalman filtering-based framework is adapted to assist the decision-maker in quantifying the network-wide information gain and SNM flow estimation accuracy. PMID:22163641

  2. Locating sensors for detecting source-to-target patterns of special nuclear material smuggling: a spatial information theoretic approach.

    PubMed

    Przybyla, Jay; Taylor, Jeffrey; Zhou, Xuesong

    2010-01-01

    In this paper, a spatial information-theoretic model is proposed to locate sensors for detecting source-to-target patterns of special nuclear material (SNM) smuggling. In order to ship the nuclear materials from a source location with SNM production to a target city, the smugglers must employ global and domestic logistics systems. This paper focuses on locating a limited set of fixed and mobile radiation sensors in a transportation network, with the intent to maximize the expected information gain and minimize the estimation error for the subsequent nuclear material detection stage. A Kalman filtering-based framework is adapted to assist the decision-maker in quantifying the network-wide information gain and SNM flow estimation accuracy. PMID:22163641

  3. When are new hippocampal neurons, born in the adult brain, integrated into the network that processes spatial information?

    PubMed

    Sandoval, C Jimena; Martínez-Claros, Marisela; Bello-Medina, Paola C; Pérez, Oswaldo; Ramírez-Amaya, Víctor

    2011-01-01

    Adult-born neurons in the dentate gyrus (DG) functionally integrate into the behaviorally relevant hippocampal networks, showing a specific Arc-expression response to spatial exploration when mature. However, it is not clear when, during the 4- to 6-week interval that is critical for survival and maturation of these neurons, this specific response develops. Therefore, we characterized Arc expression after spatial exploration or cage control conditions in adult-born neurons from rats that were injected with BrdU on one day and were sacrificed 1, 7, 15, 30, and 45 days post-BrdU injection (PBI). Triple immunostaining for NeuN, Arc, and BrdU was analyzed through the different DG layers. Arc protein expression in BrdU-positive cells was observed from day 1 to day 15 PBI but was not related to behavioral stimulation. The specific Arc-expression response to spatial exploration was observed from day 30 and 45 in about 5% of the BrdU-positive cell population. Most of the BrdU-positive neurons expressing Arc in response to spatial exploration (∼90%) were located in DG layer 1, and no Arc expression was observed in cells located in the subgranular zone (SGZ). Using the current data and that obtained previously, we propose a mathematical model suggesting that new neurons are unlikely to respond to exploration by expressing Arc after they are 301 days old, and also that in a 7-month-old rat the majority (60%) of the neurons that respond to exploration must have been born during adulthood; thus, suggesting that adult neurogenesis in the DG is highly relevant for spatial information processing. PMID:21408012

  4. When Are New Hippocampal Neurons, Born in the Adult Brain, Integrated into the Network That Processes Spatial Information?

    PubMed Central

    Sandoval, C. Jimena; Pérez, Oswaldo; Ramírez-Amaya, Víctor

    2011-01-01

    Adult-born neurons in the dentate gyrus (DG) functionally integrate into the behaviorally relevant hippocampal networks, showing a specific Arc-expression response to spatial exploration when mature. However, it is not clear when, during the 4- to 6-week interval that is critical for survival and maturation of these neurons, this specific response develops. Therefore, we characterized Arc expression after spatial exploration or cage control conditions in adult-born neurons from rats that were injected with BrdU on one day and were sacrificed 1, 7, 15, 30, and 45 days post-BrdU injection (PBI). Triple immunostaining for NeuN, Arc, and BrdU was analyzed through the different DG layers. Arc protein expression in BrdU-positive cells was observed from day 1 to day 15 PBI but was not related to behavioral stimulation. The specific Arc-expression response to spatial exploration was observed from day 30 and 45 in about 5% of the BrdU-positive cell population. Most of the BrdU-positive neurons expressing Arc in response to spatial exploration (∼90%) were located in DG layer 1, and no Arc expression was observed in cells located in the subgranular zone (SGZ). Using the current data and that obtained previously, we propose a mathematical model suggesting that new neurons are unlikely to respond to exploration by expressing Arc after they are 301 days old, and also that in a 7-month-old rat the majority (60%) of the neurons that respond to exploration must have been born during adulthood; thus, suggesting that adult neurogenesis in the DG is highly relevant for spatial information processing. PMID:21408012

  5. Low Spatial Frequency Bias in Schizophrenia is Not Face Specific: When the Integration of Coarse and Fine Information Fails

    PubMed Central

    Laprevote, Vincent; Oliva, Aude; Ternois, Anne-Sophie; Schwan, Raymund; Thomas, Pierre; Boucart, Muriel

    2013-01-01

    Studies have shown that patients with schizophrenia exhibit visual processing impairments, particularly regarding the processing of spatial frequencies. In a previous work, we found that, compared to healthy volunteers, patients were biased toward low spatial frequencies (LSF) to identify facial expression at a glance. Given the ubiquity of faces in visual perception, it remains an open question whether the LSF bias is face specific or also occurs with other visual objects. Here, 15 patients with schizophrenia and 11 healthy control adults performed a categorization task with hybrid stimuli. These stimuli were single images consisting of two different objects, a fruit and an animal, each in a specific spatial frequency range, either low (LSF) or high (HSF). Observers were asked to report if they saw an animal or a fruit. The reported category demonstrated which spatial scale was preferentially perceived in each trial. In a control experiment, participants performed the same task but with images of only a single object, either a LSF or HSF filtered animal or fruit, to verify that participants could perceive both HSF or LSF when presented in isolation. The results on the categorization task showed that patients chose more frequently LSF with hybrid stimuli compared to healthy controls. However, both populations performed equally well with HSF and LSF filtered pictures in the control experiment, demonstrating that the LSF preference found with hybrid stimuli in patients was not due to an inability to perceive HSF. The LSF preference found in schizophrenia confirms our previous study conducted with faces, and shows that this LSF bias generalizes to other categories of objects. When a broad range of spatial frequencies are present in the image, as in normal conditions of viewing, patients preferentially rely on coarse visual information contained in LSF. This result may be interpreted as a dysfunction of the guidance of HSF processing by LSF processing. PMID:23653616

  6. It wasn’t me! Motor activation from irrelevant spatial information in the absence of a response

    PubMed Central

    Bundt, Carsten; Bardi, Lara; Abrahamse, Elger L.; Brass, Marcel; Notebaert, Wim

    2015-01-01

    Embodied cognition postulates that perceptual and motor processes serve higher-order cognitive faculties like language. A major challenge for embodied cognition concerns the grounding of abstract concepts. Here we zoom in on abstract spatial concepts and ask the question to what extent the sensorimotor system is involved in processing these. Most of the empirical support in favor of an embodied perspective on (abstract) spatial information has derived from so-called compatibility effects in which a task-irrelevant feature either facilitates (for compatible trials) or hinders (in incompatible trials) responding to the task-relevant feature. This type of effect has been interpreted in terms of (task-irrelevant) feature-induced response activation. The problem with such approach is that incompatible features generate an array of task-relevant and –irrelevant activations [e.g., in primary motor cortex (M1)], and lateral hemispheric interactions render it difficult to assign credit to the task-irrelevant feature per se in driving these activations. Here, we aim to obtain a cleaner indication of response activation on the basis of abstract spatial information. We employed transcranial magnetic stimulation (TMS) to probe response activation of effectors in response to semantic, task-irrelevant stimuli (i.e., the words left and right) that did not require an overt response. Results revealed larger motor evoked potentials (MEPs) for the right (left) index finger when the word right (left) was presented. Our findings provide support for the grounding of abstract spatial concepts in the sensorimotor system. PMID:26483658

  7. Mutual information spectrum for selection of event-related spatial components. Application to eloquent motor cortex mapping

    PubMed Central

    Ossadtchi, Alexei; Pronko, Platon; Baillet, Sylvain; Pflieger, Mark E.; Stroganova, Tatiana

    2014-01-01

    Spatial component analysis is often used to explore multidimensional time series data whose sources cannot be measured directly. Several methods may be used to decompose the data into a set of spatial components with temporal loadings. Component selection is of crucial importance, and should be supported by objective criteria. In some applications, the use of a well defined component selection criterion may provide for automation of the analysis. In this paper we describe a novel approach for ranking of spatial components calculated from the EEG or MEG data recorded within evoked response paradigm. Our method is called Mutual Information (MI) Spectrum and is based on gauging the amount of MI of spatial component temporal loadings with a synthetically created reference signal. We also describe the appropriate randomization based statistical assessment scheme that can be used for selection of components with statistically significant amount of MI. Using simulated data with realistic trial to trial variations and SNR corresponding to the real recordings we demonstrate the superior performance characteristics of the described MI based measure as compared to a more conventionally used power driven gauge. We also demonstrate the application of the MI Spectrum for the selection of task-related independent components from real MEG data. We show that the MI spectrum allows to identify task-related components reliably in a consistent fashion, yielding stable results even from a small number of trials. We conclude that the proposed method fits naturally the information driven nature of ICA and can be used for routine and automatic ranking of independent components calculated from the functional neuroimaging data collected within event-related paradigms. PMID:24478692

  8. Nitrogen, Ecosystem Services and Environmental Justice: how can a Spatial Valuation Approach Inform Responsible Nutrient Management?

    NASA Astrophysics Data System (ADS)

    Crowell, M.; Compton, J.

    2012-12-01

    Spatially-explicit ecosystem service valuation (ESV) allows for the identification of the location and magnitude of services provided by natural ecosystems along with an economic measure of their significance based upon value transfer. While this provides an important function in terms of land use management, the connection between the relative values of ecosystem services, sensitivity to nutrient loading and nutrient load estimates is unexplored within both the GIS-based, benefit transfer ESV literature and among research on nutrients and ecosystem services. This research combines a GIS-based, value transfer approach to map ecosystem services in the Lower Yakima River Basin (LYRB), Washington, USA, along with estimates of nitrogen loading and demographic data to identify how nutrient management may affect ecosystem services in the basin, and who may be most connected to potential changes in ecosystem services. Our analysis combines relative values of ecosystem services with estimates of nitrogen loading and identifies subwatersheds most susceptible to reductions in valuable ecosystem services due to excess nitrogen loading. Additionally, by including demographic data as a component of the spatial analysis, we examine the connections between population income, ethnicity, N loading, and risk of ecosystem service reductions due to nutrient management practices. Based on the benefit transfer analysis, wetlands and forested areas have disproportionately high values of ecosystem services when compared to their land area in the LYRB, while pasture and cultivated crops contribute much less to the total value of ecosystem service flows in proportion to the total area for these areas in the LYRB. Further economic valuation data on specific land cover types whether from primary studies or meta-analysis is needed to refine relative measures of ecosystem service values and more confidently describe these values in specific dollar amounts. Additionally, limits in spatial data

  9. Converting local spectral and spatial information from a priori classifiers into contextual knowledge for impervious surface classification

    NASA Astrophysics Data System (ADS)

    Luo, Li; Mountrakis, Giorgos

    2011-09-01

    A classification model was demonstrated that explored spectral and spatial contextual information from previously classified neighbors to improve classification of remaining unclassified pixels. The classification was composed by two major steps, the a priori and the a posteriori classifications. The a priori algorithm classified the less difficult image portion. The a posteriori classifier operated on the more challenging image parts and strived to enhance accuracy by converting classified information from the a priori process into specific knowledge. The novelty of this work relies on the substitution of image-wide information with local spectral representations and spatial correlations, in essence classifying each pixel using exclusively neighboring behavior. Furthermore, the a posteriori classifier is a simple and intuitive algorithm, adjusted to perform in a localized setting for the task requirements. A 2001 and a 2006 Landsat scene from Central New York were used to assess the performance on an impervious classification task. The proposed method was compared with a back propagation neural network. Kappa statistic values in the corresponding applicable datasets increased from 18.67 to 24.05 for the 2006 scene, and from 22.92 to 35.76 for the 2001 scene classification, mostly correcting misclassifications between impervious and soil pixels. This finding suggests that simple classifiers have the ability to surpass complex classifiers through incorporation of partial results and an elegant multi-process framework.

  10. Spatial integration of optic flow information in direction of heading judgments

    PubMed Central

    Issen, Laurel; Huxlin, Krystel R.; Knill, David

    2015-01-01

    While we know that humans are extremely sensitive to optic flow information about direction of heading, we do not know how they integrate information across the visual field. We adapted the standard cue perturbation paradigm to investigate how young adult observers integrate optic flow information from different regions of the visual field to judge direction of heading. First, subjects judged direction of heading when viewing a three-dimensional field of random dots simulating linear translation through the world. We independently perturbed the flow in one visual field quadrant to indicate a different direction of heading relative to the other three quadrants. We then used subjects' judgments of direction of heading to estimate the relative influence of flow information in each quadrant on perception. Human subjects behaved similarly to the ideal observer in terms of integrating motion information across the visual field with one exception: Subjects overweighted information in the upper half of the visual field. The upper-field bias was robust under several different stimulus conditions, suggesting that it may represent a physiological adaptation to the uneven distribution of task-relevant motion information in our visual world. PMID:26024461

  11. Sustained maintenance of somatotopic information in brain regions recruited by tactile working memory.

    PubMed

    Katus, Tobias; Müller, Matthias M; Eimer, Martin

    2015-01-28

    To adaptively guide ongoing behavior, representations in working memory (WM) often have to be modified in line with changing task demands. We used event-related potentials (ERPs) to demonstrate that tactile WM representations are stored in modality-specific cortical regions, that the goal-directed modulation of these representations is mediated through hemispheric-specific activation of somatosensory areas, and that the rehearsal of somatotopic coordinates in memory is accomplished by modality-specific spatial attention mechanisms. Participants encoded two tactile sample stimuli presented simultaneously to the left and right hands, before visual retro-cues indicated which of these stimuli had to be retained to be matched with a subsequent test stimulus on the same hand. Retro-cues triggered a sustained tactile contralateral delay activity component with a scalp topography over somatosensory cortex contralateral to the cued hand. Early somatosensory ERP components to task-irrelevant probe stimuli (that were presented after the retro-cues) and to subsequent test stimuli were enhanced when these stimuli appeared at the currently memorized location relative to other locations on the cued hand, demonstrating that a precise focus of spatial attention was established during the selective maintenance of tactile events in WM. These effects were observed regardless of whether participants performed the matching task with uncrossed or crossed hands, indicating that WM representations in this task were based on somatotopic rather than allocentric spatial coordinates. In conclusion, spatial rehearsal in tactile WM operates within somatotopically organized sensory brain areas that have been recruited for information storage. PMID:25632117

  12. Sustained Maintenance of Somatotopic Information in Brain Regions Recruited by Tactile Working Memory

    PubMed Central

    Katus, Tobias; Eimer, Martin

    2015-01-01

    To adaptively guide ongoing behavior, representations in working memory (WM) often have to be modified in line with changing task demands. We used event-related potentials (ERPs) to demonstrate that tactile WM representations are stored in modality-specific cortical regions, that the goal-directed modulation of these representations is mediated through hemispheric-specific activation of somatosensory areas, and that the rehearsal of somatotopic coordinates in memory is accomplished by modality-specific spatial attention mechanisms. Participants encoded two tactile sample stimuli presented simultaneously to the left and right hands, before visual retro-cues indicated which of these stimuli had to be retained to be matched with a subsequent test stimulus on the same hand. Retro-cues triggered a sustained tactile contralateral delay activity component with a scalp topography over somatosensory cortex contralateral to the cued hand. Early somatosensory ERP components to task-irrelevant probe stimuli (that were presented after the retro-cues) and to subsequent test stimuli were enhanced when these stimuli appeared at the currently memorized location relative to other locations on the cued hand, demonstrating that a precise focus of spatial attention was established during the selective maintenance of tactile events in WM. These effects were observed regardless of whether participants performed the matching task with uncrossed or crossed hands, indicating that WM representations in this task were based on somatotopic rather than allocentric spatial coordinates. In conclusion, spatial rehearsal in tactile WM operates within somatotopically organized sensory brain areas that have been recruited for information storage. PMID:25632117

  13. Climate-physiographically differentiated Pan-European landslide susceptibility assessment using spatial multi-criteria evaluation and transnational landslide information

    NASA Astrophysics Data System (ADS)

    Günther, Andreas; Van Den Eeckhaut, Miet; Malet, Jean-Philippe; Reichenbach, Paola; Hervás, Javier

    2014-11-01

    With the adoption of the EU Thematic Strategy for Soil Protection in 2006, small-scale (1:1 M) assessments of threats affecting soils over Europe received increasing attention. As landslides have been recognized as one of eight threats requiring a Pan-European evaluation, we present an approach for landslide susceptibility evaluation at the continental scale over Europe. Unlike previous continental and global scale landslide susceptibility studies not utilizing spatial information on the events, we collected more than 102,000 landslide locations in 22 European countries. These landslides are heterogeneously distributed over Europe, but are indispensable for the evaluation and classification of Pan-European datasets used as spatial predictors, and the validation of the resulting assessments. For the analysis we subdivided the European territory into seven different climate-physiographical zones by combining morphometric and climatic data for terrain differentiation, and adding a coastal zone defined as a 1 km strip inland from the coastline. Landslide susceptibility modeling was performed for each zone using heuristic spatial multicriteria evaluations supported by analytical hierarchy processes, and validated with the inventory data using the receiver operating characteristics. In contrast to purely data-driven statistical modeling techniques, our semi-quantitative approach is capable to introduce expert knowledge into the analysis, which is indispensable considering quality and resolution of the input data, and incompleteness and bias in the inventory information. The reliability of the resulting susceptibility map ELSUS 1000 Version 1 (1 km resolution) was examined on an administrative terrain unit level in areas with landslide information and through the comparison with available national susceptibility zonations. These evaluations suggest that although the ELSUS 1000 is capable for a correct synoptic prediction of landslide susceptibility in the majority of the

  14. Familiar environments enhance object and spatial memory in both younger and older adults.

    PubMed

    Merriman, Niamh A; Ondřej, Jan; Roudaia, Eugenie; O'Sullivan, Carol; Newell, Fiona N

    2016-06-01

    Recent evidence suggests that familiarity with an environment may protect against spatial memory decline for familiar objects in older adults. We investigated whether a familiar context also reduces age-related decline in spatial memory for novel objects. Twenty-four younger and 23 older participants viewed a virtual rendering of a local environment along two different routes, each through a well-known (West) or lesser-known (East) area within the environment. Older and younger participants reported being more familiar with one (i.e. West) area than the other. In each trial, participants were presented with one route and were instructed to learn ten novel objects and their locations along the route. Following learning, participants immediately completed five test blocks: an object recognition task, an egocentric spatial processing (direction judgement) task, an allocentric spatial processing (proximity judgement) task and two pen-and-paper tests to measure cognitive mapping abilities. First we found an age effect with worse performance by older than younger adults in all spatial tasks, particularly in allocentric spatial processing. However, our results suggested better memory for objects and directions, but not proximity judgements, when the task was associated with more familiar than unfamiliar contexts, in both age groups. There was no benefit of context when a separate young adult group (N = 24) was tested, who reported being equally familiar with both areas. These results suggest an important facilitatory role of context familiarity on object recognition, and in particular egocentric spatial memory, and have implications for enhancing spatial memory in older adults. PMID:26821318

  15. The use of a spatial information system in the management of HIV/AIDS in South Africa

    PubMed Central

    Busgeeth, Karishma; Rivett, Ulrike

    2004-01-01

    Background South Africa is experiencing an HIV/AIDS pandemic of shattering dimensions. The availability and provision of antiretroviral (ARV) drugs could bring relief to the situation, but the treatment is unfortunately complex with each patient being assigned a different antiretroviral therapy varying in diet-medication regiment. The context of South Africa, its variety of urban and rural settings adds to the challenge of administering and monitoring the HIV+ person throughout the treatment, which will last for the rest of their lives. The lack of physical infrastructure, reliable statistics and adequate resources hinder the efficient management of HIV/AIDS. Results The collection of reliable data will be a first step to assess the status of HIV/AIDS in communities. A number of hospitals have started this process using the conventional approach to collect information about their patients using a paper-based system. Since time is of essence in the fight against the pandemic, data exchange between various hospitals, municipalities and decision-making bodies is becoming more and more important. The logical response to such a need is a computerised system, which will collect and administer HIV/AIDS related information within the local context and allow a monitored access to the data from a number of stakeholders. Conclusions The purpose of this study was to design and develop an HIV/AIDS database, which is embedded in a Spatial Information Management System. The pilot study area is the Gugulethu township in Cape Town where more than 27% of the 325 000 residents are HIV+. It is shown that the implementation of the HIV/AIDS database and the Spatial Information Management System can play a critical role in determining where and when to intervene, improving the quality of care for HIV+ patients, increasing accessibility of service and delivering a cost-effective mode of information. PMID:15239839

  16. Spatial Displays and Spatial Instruments

    NASA Technical Reports Server (NTRS)

    Ellis, Stephen R. (Editor); Kaiser, Mary K. (Editor); Grunwald, Arthur J. (Editor)

    1989-01-01

    The conference proceedings topics are divided into two main areas: (1) issues of spatial and picture perception raised by graphical electronic displays of spatial information; and (2) design questions raised by the practical experience of designers actually defining new spatial instruments for use in new aircraft and spacecraft. Each topic is considered from both a theoretical and an applied direction. Emphasis is placed on discussion of phenomena and determination of design principles.

  17. Maintaining Consistency of Spatial Information in the Hippocampal Network: A Combinatorial Geometry Model.

    PubMed

    Dabaghian, Y

    2016-06-01

    Place cells in the rat hippocampus play a key role in creating the animal's internal representation of the world. During active navigation, these cells spike only in discrete locations, together encoding a map of the environment. Electrophysiological recordings have shown that the animal can revisit this map mentally during both sleep and awake states, reactivating the place cells that fired during its exploration in the same sequence in which they were originally activated. Although consistency of place cell activity during active navigation is arguably enforced by sensory and proprioceptive inputs, it remains unclear how a consistent representation of space can be maintained during spontaneous replay. We propose a model that can account for this phenomenon and suggest that a spatially consistent replay requires a number of constraints on the hippocampal network that affect its synaptic architecture and the statistics of synaptic connection strengths. PMID:27137840

  18. Disease Prediction based on Functional Connectomes using a Scalable and Spatially-Informed Support Vector Machine

    PubMed Central

    Watanabe, Takanori; Kessler, Daniel; Scott, Clayton; Angstadt, Michael; Sripada, Chandra

    2014-01-01

    Substantial evidence indicates that major psychiatric disorders are associated with distributed neural dysconnectivity, leading to strong interest in using neuroimaging methods to accurately predict disorder status. In this work, we are specifically interested in a multivariate approach that uses features derived from whole-brain resting state functional connectomes. However, functional connectomes reside in a high dimensional space, which complicates model interpretation and introduces numerous statistical and computational challenges. Traditional feature selection techniques are used to reduce data dimensionality, but are blind to the spatial structure of the connectomes. We propose a regularization framework where the 6-D structure of the functional connectome (defined by pairs of points in 3-D space) is explicitly taken into account via the fused Lasso or the GraphNet regularizer. Our method only restricts the loss function to be convex and margin-based, allowing non-differentiable loss functions such as the hinge-loss to be used. Using the fused Lasso or GraphNet regularizer with the hinge-loss leads to a structured sparse support vector machine (SVM) with embedded feature selection. We introduce a novel efficient optimization algorithm based on the augmented Lagrangian and the classical alternating direction method, which can solve both fused Lasso and GraphNet regularized SVM with very little modification. We also demonstrate that the inner subproblems of the algorithm can be solved efficiently in analytic form by coupling the variable splitting strategy with a data augmentation scheme. Experiments on simulated data and resting state scans from a large schizophrenia dataset show that our proposed approach can identify predictive regions that are spatially contiguous in the 6-D “connectome space,” offering an additional layer of interpretability that could provide new insights about various disease processes. PMID:24704268

  19. Combining time-frequency and spatial information for the detection of sleep spindles

    PubMed Central

    O'Reilly, Christian; Godbout, Jonathan; Carrier, Julie; Lina, Jean-Marc

    2015-01-01

    EEG sleep spindles are short (0.5–2.0 s) bursts of activity in the 11–16 Hz band occurring during non-rapid eye movement (NREM) sleep. This sporadic activity is thought to play a role in memory consolidation, brain plasticity, and protection of sleep integrity. Many automatic detectors have been proposed to assist or replace experts for sleep spindle scoring. However, these algorithms usually detect too many events making it difficult to achieve a good tradeoff between sensitivity (Se) and false detection rate (FDr). In this work, we propose a semi-automatic detector comprising a sensitivity phase based on well-established criteria followed by a specificity phase using spatial and spectral criteria. In the sensitivity phase, selected events are those which amplitude in the 10–16 Hz band and spectral ratio characteristics both reject a null hypothesis (p < 0.1) stating that the considered event is not a spindle. This null hypothesis is constructed from events occurring during rapid eye movement (REM) sleep epochs. In the specificity phase, a hierarchical clustering of the selected candidates is done based on events' frequency and spatial position along the anterior-posterior axis. Only events from the classes grouping most (at least 80%) spindles scored by an expert are kept. We obtain Se = 93.2% and FDr = 93.0% in the first phase and Se = 85.4% and FDr = 86.2% in the second phase. For these two phases, Matthew's correlation coefficients are respectively 0.228 and 0.324. Results suggest that spindles are defined by specific spatio-spectral properties and that automatic detection methods can be improved by considering these features. PMID:25745392

  20. Optical encryption in spatially-incoherent light using two LC SLMs for both information input and encryption element imaging

    NASA Astrophysics Data System (ADS)

    Bondareva, Alyona P.; Cheremkhin, Pavel A.; Evtikhiev, Nikolay N.; Krasnov, Vitaly V.; Rodin, Vladislav G.; Starikov, Sergey N.

    2014-10-01

    At present time methods of optical encryption are actively developed. The majority of existing methods of optical encryption use not only light intensity distribution, easily registered with photosensors, but also its phase distribution which require application of complex holographic schemes in conjunction with spatially coherent monochromatic illumination. This leads to complex optical schemes and low decryption quality. To eliminate these disadvantages it is possible to implement optical encryption using spatially incoherent monochromatic illumination which requires registration of light intensity distribution only. Encryption is accomplished by means of optical convolution of image of scene to be encrypted and encryption diffractive optical element (DOE) point spread function (PSF) which serves as encryption key. Encryption process is described as follows. Scene is illuminated with spatially-incoherent monochromatic light. In the absence of encryption DOE lens forms image of scene in photosensor plane. DOE serves as encryption element, its PSF - encryption key. Light passing through DOE forms convolution of object image and DOE PSF. Registered by photosensor convolution is encrypted image. Decryption was conducted numerically on computer by means of inverse filtration with regularization. Kinoforms were used as encryption DOE because they have single diffraction order. Two liquid crystal (LC) spatial light modulators (SLM) were used to implement dynamic digital information input and dynamic encryption key change. As input scene amplitude LC SLM HoloEye LC2002 with 800×600 pixels 32×32 μm2 and 256 gray levels was used. To image synthesized encryption kinoforms phase LC SLM HoloEye PLUTO VIS with 1920×1080 pixels 8×8 μm2 and 256 phase levels was used. Set of test images was successfully optically encrypted and then numerically decrypted. Encrypted images contents are hidden. Decrypted images despite quite high noise levels are positively recognizable

  1. Concepts for conformal and body-axis attitude information for spatial awareness presented in a helmet-mounted display

    NASA Technical Reports Server (NTRS)

    Jones, Denise R.; Abbott, Terence S.; Burley, James R., II

    1993-01-01

    A piloted simulation study has been conducted to evaluate two methods of presenting attitude information in a helmet-mounted display (HMD) for spatial awareness in a fighter airplane. One method, the body-axis concept, displayed the information relative to the body axis of the airplane. The quantitative results of this study favored the body-axis concept. Although no statistically significant differences were noted for either the pilots' understanding of roll attitude or target position, the pilots made pitch judgment errors three times more often with the conformal display. The subjective results showed the body-axis display did not cause attitude confusion, a prior concern with this display. In the posttest comments, the pilots overwhelmingly selected the body-axis display as the display of choice.

  2. Extraction of residential information from high-spatial resolution image integrated with upscaling methods and object multi-features

    NASA Astrophysics Data System (ADS)

    Dong, Lixin; Wu, Bingfang

    2007-11-01

    Monitoring residential areas at a regional scale, and even at a global scale, has become an increasingly important topic. However, extraction of residential information was still a difficulty and challenging task, such as multiple usable data selection and automatic or semi-automatic techniques. In metropolitan area, such as Beijing, urban sprawl has brought enormous pressure on rural and natural environments. Given a case study, a new strategy of extracting of residential information integrating the upscaling methods and object multi-features was introduced in high resolution SPOT fused image. Multi-resolution dataset were built using upscaling methods, and optimal resolution image was selected by semi-variance analysis approach. Relevant optimal spatial resolution images were adopted for different type of residential area (city, town and rural residence). Secondly, object multi-features, including spectral information, generic shape features, class related features, and new computed features, were introduced. An efficient decision tree and Class Semantic Representation were set up based on object multi-features. And different classes of residential area were extracted from multi-resolution image. Afterwards, further discussion and comparison about improving the efficiency and accuracy of classification with the proposed approach were presented. The results showed that the optimal resolution image selected by upscaling and semi-variance method successfully decreased the heterogeneous, smoothed the noise influence, decreased computational, storage burdens and improved classification efficiency in high spatial resolution image. The Class Semantic Representation and decision tree based on object multi-features improved the overall accuracy and diminished the 'salt and pepper effect'. The new image analysis approach offered a satisfactory solution for extracting residential information quickly and efficiently.

  3. Gravity and spatial orientation in virtual 3D-mazes.

    PubMed

    Vidal, Manuel; Lipshits, Mark; McIntyre, Joseph; Berthoz, Alain

    2003-01-01

    In order to bring new insights into the processing of 3D spatial information, we conducted experiments on the capacity of human subjects to memorize 3D-structured environments, such as buildings with several floors or the potentially complex 3D structure of an orbital space station. We had subjects move passively in one of two different exploration modes, through a visual virtual environment that consisted of a series of connected tunnels. In upright displacement, self-rotation when going around corners in the tunnels was limited to yaw rotations. For horizontal translations, subjects faced forward in the direction of motion. When moving up or down through vertical segments of the 3D tunnels, however, subjects facing the tunnel wall, remaining upright as if moving up and down in a glass elevator. In the unconstrained displacement mode, subjects would appear to climb or dive face-forward when moving vertically; thus, in this mode subjects could experience visual flow consistent with rotations about any of the 3 canonical axes. In a previous experiment, subjects were asked to determine whether a static, outside view of a test tunnel corresponded or not to the tunnel through which they had just passed. Results showed that performance was better on this task for the upright than for the unconstrained displacement mode; i.e. when subjects remained "upright" with respect to the virtual environment as defined by subject's posture in the first segment. This effect suggests that gravity may provide a key reference frame used in the shift between egocentric and allocentric representations of the 3D virtual world. To check whether it is the polarizing effects of gravity that leads to the favoring of the upright displacement mode, the experimental paradigm was adapted for orbital flight and performed by cosmonauts onboard the International Space Station. For these flight experiments the previous recognition task was replaced by a computerized reconstruction task, which proved

  4. Current practices in spatial analysis of cancer data: mapping health statistics to inform policymakers and the public

    PubMed Central

    Bell, B Sue; Hoskins, Richard E; Pickle, Linda Williams; Wartenberg, Daniel

    2006-01-01

    Background To communicate population-based cancer statistics, cancer researchers have a long tradition of presenting data in a spatial representation, or map. Historically, health data were presented in printed atlases in which the map producer selected the content and format. The availability of geographic information systems (GIS) with comprehensive mapping and spatial analysis capability for desktop and Internet mapping has greatly expanded the number of producers and consumers of health maps, including policymakers and the public. Because health maps, particularly ones that show elevated cancer rates, historically have raised public concerns, it is essential that these maps be designed to be accurate, clear, and interpretable for the broad range of users who may view them. This article focuses on designing maps to communicate effectively. It is based on years of research into the use of health maps for communicating among public health researchers. Results The basics for designing maps that communicate effectively are similar to the basics for any mode of communication. Tasks include deciding on the purpose, knowing the audience and its characteristics, choosing a media suitable for both the purpose and the audience, and finally testing the map design to ensure that it suits the purpose with the intended audience, and communicates accurately and effectively. Special considerations for health maps include ensuring confidentiality and reflecting the uncertainty of small area statistics. Statistical maps need to be based on sound practices and principles developed by the statistical and cartographic communities. Conclusion The biggest challenge is to ensure that maps of health statistics inform without misinforming. Advances in the sciences of cartography, statistics, and visualization of spatial data are constantly expanding the toolkit available to mapmakers to meet this challenge. Asking potential users to answer questions or to talk about what they see is

  5. Spatial Heat Maps from Fast Information Matching of Fast and Slow Degrees of Freedom: Application to Molecular Dynamics Simulations.

    PubMed

    Kovacs, Julio A; Wriggers, Willy

    2016-08-25

    We introduce a fast information matching (FIM) method for transforming time domain data into spatial images through handshaking between fast and slow degrees of freedom. The analytics takes advantage of the detailed time series available from biomolecular computer simulations, and it yields spatial heat maps that can be visualized on 3D molecular structures or in the form of interaction networks. The speed of our efficient mutual information solver is on the order of a basic Pearson cross-correlation calculation. We demonstrate that the FIM method is superior to linear cross-correlation for the detection of nonlinear dependence in challenging situations where measures for the global dynamics (the "activity") diverge. The analytics is applied to the detection of hinge-bending hot spots and to the prediction of pairwise contacts between residues that are relevant for the global activity exhibited by the molecular dynamics (MD) trajectories. Application examples from various MD laboratories include the millisecond bovine pancreatic trypsin inhibitor (BPTI) trajectory using canonical MD, a Gaussian accelerated MD folding trajectory of chignolin, and the heat-induced unfolding of engrailed homeodomain (EnHD). The FIM implementation will be freely disseminated with our open-source package, TimeScapes. PMID:27169521

  6. Forming first impressions of others in schizophrenia: impairments in fast processing and in use of spatial frequency information.

    PubMed

    Vakhrusheva, J; Zemon, V; Bar, M; Weiskopf, N G; Tremeau, F; Petkova, E; Su, Z; Abeles, I Y; Butler, P D

    2014-12-01

    Individuals form first impressions of others all the time, which affects their social functioning. Typical adults form threat impressions in faces with neutral expressions quickly, requiring less than 40 ms. These impressions appear to be mediated by low spatial frequency (LSF) content in the images. Little is known, however, about mechanisms of first impression formation in schizophrenia. The current study investigated how quickly individuals with schizophrenia can form consistent impressions of threat compared with controls and explored the mechanisms involved. Patients and controls were presented intact, LSF- or high spatial frequency (HSF)-filtered faces with durations that varied from 39 to 1703 ms and were asked to rate how threatening each face was on a scale from 1 to 5. In order to assess the speed of impression formation for intact faces, correlations were calculated for ratings made at each duration compared to a reference duration of 1703 ms for each group. Controls demonstrated a significant relation for intact faces presented for 39 ms, whereas patients required 390 ms to demonstrate a significant relation with the reference duration. For controls, LSFs primarily contributed to the formation of consistent threat impressions at 39 ms, whereas patients showed a trend for utilizing both LSF and HSF information to form consistent threat impressions at 390 ms. Results indicate that individuals with schizophrenia require a greater integration time to form a stable "first impression" of threat, which may be related to the need to utilize compensatory mechanisms such as HSF, as well as LSF, information. PMID:25458862

  7. USING INFORMATION ON SPATIAL VARIABILITY OF SMALL ESTUARIES IN DESIGNING LARGE GEOGRAPHIC SCALE ESTUARINE MONITORING PROGRAMS

    EPA Science Inventory

    In the early 1990s, EPA's Environmental Monitoring and Assessment Program (EMAP) documented the ecological condition of the overall population of small estuaries along the Mid-Atlantic coast of the United States. However, the Program did not provide information on the condition o...

  8. USING INFORMATION ON SPATIAL VARIABILITY OF SMALL ESTUARIES IN DESIGNING LARGE SCALE ESTUARINE MONITORING PROGRAMS

    EPA Science Inventory

    In the early 1990's, EPA's Environmental Monitoring and Assessment program (EMAP) documented the ecological condition of the overall population of small estuaries along the mid-Atlantic coast of the United States. However, the Program did not provide detailed information on the c...

  9. Using JournalMap to link spatial information with ecological site descriptions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    JournalMap is a scientific literature search engine that empowers you to find relevant research based on location and biophysical variables as well as traditional keyword searches. All publications are geotagged based on reported location information and plotted on a world map showing where the rese...

  10. 75 FR 16749 - Federal Geospatial Summit To Provide Information on Upcoming Improvements To the National Spatial...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-02

    ...: National Geodetic Survey (NGS), National Ocean Service (NOS), National Oceanic and Atmospheric Administration (NOAA), Commerce. ACTION: Public meeting. SUMMARY: The National Geodetic Survey (NGS) will host a... . SUPPLEMENTARY INFORMATION: Abstract In January 2008, NGS adopted a 10-year plan identifying the need to...

  11. Spatially invariant coding of numerical information in functionally defined subregions of human parietal cortex.

    PubMed

    Eger, E; Pinel, P; Dehaene, S; Kleinschmidt, A

    2015-05-01

    Macaque electrophysiology has revealed neurons responsive to number in lateral (LIP) and ventral (VIP) intraparietal areas. Recently, fMRI pattern recognition revealed information discriminative of individual numbers in human parietal cortex but without precisely localizing the relevant sites or testing for subregions with different response profiles. Here, we defined the human functional equivalents of LIP (feLIP) and VIP (feVIP) using neurophysiologically motivated localizers. We applied multivariate pattern recognition to investigate whether both regions represent numerical information and whether number codes are position specific or invariant. In a delayed number comparison paradigm with laterally presented numerosities, parietal cortex discriminated between numerosities better than early visual cortex, and discrimination generalized across hemifields in parietal, but not early visual cortex. Activation patterns in the 2 parietal regions of interest did not differ in the coding of position-specific or position-independent number information, but in the expression of a numerical distance effect which was more pronounced in feLIP. Thus, the representation of number in parietal cortex is at least partially position invariant. Both feLIP and feVIP contain information about individual numerosities in humans, but feLIP hosts a coarser representation of numerosity than feVIP, compatible with either broader tuning or a summation code. PMID:24293562

  12. A bayesian integrative model for genetical genomics with spatially informed variable selection.

    PubMed

    Cassese, Alberto; Guindani, Michele; Vannucci, Marina

    2014-01-01

    We consider a Bayesian hierarchical model for the integration of gene expression levels with comparative genomic hybridization (CGH) array measurements collected on the same subjects. The approach defines a measurement error model that relates the gene expression levels to latent copy number states. In turn, the latent states are related to the observed surrogate CGH measurements via a hidden Markov model. The model further incorporates variable selection with a spatial prior based on a probit link that exploits dependencies across adjacent DNA segments. Posterior inference is carried out via Markov chain Monte Carlo stochastic search techniques. We study the performance of the model in simulations and show better results than those achieved with recently proposed alternative priors. We also show an application to data from a genomic study on lung squamous cell carcinoma, where we identify potential candidates of associations between copy number variants and the transcriptional activity of target genes. Gene ontology (GO) analyses of our findings reveal enrichments in genes that code for proteins involved in cancer. Our model also identifies a number of potential candidate biomarkers for further experimental validation. PMID:25288877

  13. Integrating geographic information systems and remote sensing with spatial econometric and mixed logit models for environmental valuation

    NASA Astrophysics Data System (ADS)

    Wells, Aaron Raymond

    This research focuses on the Emory and Obed Watersheds in the Cumberland Plateau in Central Tennessee and the Lower Hatchie River Watershed in West Tennessee. A framework based on market and nonmarket valuation techniques was used to empirically estimate economic values for environmental amenities and negative externalities in these areas. The specific techniques employed include a variation of hedonic pricing and discrete choice conjoint analysis (i.e., choice modeling), in addition to geographic information systems (GIS) and remote sensing. Microeconomic models of agent behavior, including random utility theory and profit maximization, provide the principal theoretical foundation linking valuation techniques and econometric models. The generalized method of moments estimator for a first-order spatial autoregressive function and mixed logit models are the principal econometric methods applied within the framework. The dissertation is subdivided into three separate chapters written in a manuscript format. The first chapter provides the necessary theoretical and mathematical conditions that must be satisfied in order for a forest amenity enhancement program to be implemented. These conditions include utility, value, and profit maximization. The second chapter evaluates the effect of forest land cover and information about future land use change on respondent preferences and willingness to pay for alternative hypothetical forest amenity enhancement options. Land use change information and the amount of forest land cover significantly influenced respondent preferences, choices, and stated willingness to pay. Hicksian welfare estimates for proposed enhancement options ranged from 57.42 to 25.53, depending on the policy specification, information level, and econometric model. The third chapter presents economic values for negative externalities associated with channelization that affect the productivity and overall market value of forested wetlands. Results of robust

  14. Development of an integrated application portal for environmental spatial information dissemination in the Nestos river basin

    NASA Astrophysics Data System (ADS)

    Zalidis, George; Karapetsas, Nikolaos; Skoulikaris, Charalampos; Misopolinos, Lazaros; Manesis, Charalampos

    2013-08-01

    Water resources management is a comprehensive planning process dimensioning all water related components. With this in mind, the EU Water Framework Directive (WFD) requires reliable and continuous water monitoring and collection of qualitative information in order to support decision making concerning water pollution events, focusing primarily on civil protection. The present research study initiates the coupling of water quality - quantity monitoring techniques and telemetric systems with geographic information system (GIS) based map server technologies for the near real time warning about potential water pollution events. The study is being implemented in the Greek part of the transboundary Nestos river basin and forms part of the Bulgarian and Greek European Territorial Cooperation Programme 2007-2013. The aim of this partnership is to develop an operational supportive mechanism for the Competent Authorities of water management in both countries in order to facilitate the planning and implementation of sustainable water management along with civil protection.

  15. Spatial database for the management of "urban geology" geothematic information: the case of Drama City, Greece

    NASA Astrophysics Data System (ADS)

    Pantelias, Eustathios; Zervakou, Alexandra D.; Tsombos, Panagiotis I.; Nikolakopoulos, Konstantinos G.

    2008-10-01

    The aggregation of population in big cities leads to the concentration of human activities, economic wealth, over consumption of natural resources and urban growth without planning and sustainable management. As a result, urban societies are exposed to various dangers and threats with economical, social, ecological - environmental impacts on the urban surroundings. Problems associated with urban development are related to their geological conditions and those of their surroundings, e.g. flooding, land subsidence, groundwater pollution, soil contamination, earthquakes, landslides, etc. For these reasons, no sustainable urban planning can be done without geological information support. The first systematic recording, codification and documentation of "urban geology" geothematic information in Greece is implemented by the Institute of Geological and Mineral Exploration (I.G.M.E.) in the frame of project "Collection, codification and documentation of geothematic information for urban and suburban areas in Greece - pilot applications". Through the implementation of this project, all geothematic information derived from geological mapping, geotechnical - geochemical - geophysical research and measurements in four pilot areas of Greece Drama (North Greece), Nafplio & Sparti (Peloponnesus) and Thrakomakedones (Attica) is stored and processed in specially designed geodatabases in GIS environment containing vector and raster data. For the specific GIS application ArcGIS Personal Geodatabase is used. Data is classified in geothematic layers, grouped in geothematic datasets (e.g. Topography, Geology - Tectonics, Submarine Geology, Technical Geology, Hydrogeology, Soils, Radioactive elements, etc) and being processed in order to produced multifunctional geothematic maps. All compiled data constitute the essential base for land use planning and environmental protection in specific urban areas. With the termination of the project the produced geodatabase and other digital data

  16. DUAL PATHWAYS FOR HAPTIC AND VISUAL PERCEPTION OF SPATIAL AND TEXTURE INFORMATION

    PubMed Central

    Sathian, K.; Lacey, Simon; Stilla, Randall; Gibson, Gregory O.; Deshpande, Gopikrishna; Hu, Xiaoping; LaConte, Stephen; Glielmi, Christopher

    2011-01-01

    Segregation of information flow along a dorsally directed pathway for processing object location and a ventrally directed pathway for processing object identity is well established in the visual and auditory systems, but is less clear in the somatosensory system. We hypothesized that segregation of location vs. identity information in touch would be evident if texture is the relevant property for stimulus identity, given the salience of texture for touch. Here, we used functional magnetic resonance imaging (fMRI) to investigate whether the pathways for haptic and visual processing of location and texture are segregated, and the extent of bisensory convergence. Haptic texture-selectivity was found in the parietal operculum and posterior visual cortex bilaterally, and in parts of left inferior frontal cortex. There was bisensory texture-selectivity at some of these sites in posterior visual and left inferior frontal cortex. Connectivity analyses demonstrated, in each modality, flow of information from unisensory non-selective areas to modality-specific texture-selective areas and further to bisensory texture-selective areas. Location-selectivity was mostly bisensory, occurring in dorsal areas, including the frontal eye fields and multiple regions around the intraparietal sulcus bilaterally. Many of these regions received input from unisensory areas in both modalities. Together with earlier studies, the activation and connectivity analyses of the present study establish that somatosensory processing flows into segregated pathways for location and object identity information. The location-selective somatosensory pathway converges with its visual counterpart in dorsal frontoparietal cortex, while the texture-selective somatosensory pathway runs through the parietal operculum before converging with its visual counterpart in visual and frontal cortex. Both segregation of sensory processing according to object property and multisensory convergence appear to be universal

  17. Spatial representation of alarm pheromone information in a secondary olfactory centre in the ant brain.

    PubMed

    Yamagata, Nobuhiro; Mizunami, Makoto

    2010-08-22

    Pheromones play major roles in intraspecific communication in many animals. Elaborated communication systems in eusocial insects provide excellent materials to study neural mechanisms for social pheromone processing. We previously reported that alarm pheromone information is processed in a specific cluster of glomeruli in the antennal lobe of the ant Camponotus obscuripes. However, representation of alarm pheromone information in a secondary olfactory centre is unknown in any animal. Olfactory information in the antennal lobe is transmitted to secondary olfactory centres, including the lateral horn, by projection neurons (PNs). In this study, we compared distributions of terminal boutons of alarm pheromone-sensitive and -insensitive PNs in the lateral horn of ants. Distributions of their dendrites largely overlapped, but there was a region where boutons of pheromone-sensitive PNs, but not those of pheromone-insensitive PNs, were significantly denser than in the rest of the lateral horn. Moreover, most of a major type of pheromone-sensitive efferent neurons from the lateral horn extended dendritic branches in this region, suggesting specialization of this region for alarm pheromone processing. This study is the first study to demonstrate the presence of specialized areas for the processing of a non-sexual, social pheromone in the secondary olfactory centre in any animal. PMID:20375054

  18. Using Spatial Information Technologies as Monitoring Devices in International Watershed Conservation along the Senegal River Basin of West Africa

    PubMed Central

    Merem, Edmund C.; Twumasi, Yaw A.

    2008-01-01

    In this paper, we present the applications of spatial technologies—Geographic Information Systems (GIS) and remote sensing—in the international monitoring of river basins particularly analyzing the ecological, hydrological, and socio-economic issues along the Senegal River. The literature on multinational water crisis has for decades focused on mediation aspects of trans-boundary watershed management resulting in limited emphasis placed on the application of advances in geo-spatial information technologies in multinational watershed conservation in the arid areas of the West African sub-region within the Senegal River Basin for decision-making and monitoring. While the basin offers life support in a complex ecosystem that stretches across different nations in a mostly desert region characterized by water scarcity and subsistence economies, there exists recurrent environmental stress induced by both socio-economic and physical factors. Part of the problems consists of flooding, drought and limited access to sufficient quantities of water. These remain particularly sensitive issues that are crucial for the health of a rapidly growing population and the economy. The problems are further compounded due to the threats of climate change and the resultant degradation of almost the region’s entire natural resources base. While the pace at which the institutional framework for managing the waters offers opportunities for hydro electricity and irrigated agriculture through the proliferation of dams, it has raised other serious concerns in the region. Even where data exists for confronting these issues, some of them are incompatible and dispersed among different agencies. This not only widens the geo-spatial data gaps, but it hinders the ability to monitor water problems along the basin. This study will fill that gap in research through mix scale methods built on descriptive statistics, GIS and remote sensing techniques by generating spatially referenced data to

  19. Using spatial information technologies as monitoring devices in international watershed conservation along the Senegal River Basin of West Africa.

    PubMed

    Merem, Edmund C; Twumasi, Yaw A

    2008-12-01

    In this paper, we present the applications of spatial technologies-Geographic Information Systems (GIS) and remote sensing-in the international monitoring of river basins particularly analyzing the ecological, hydrological, and socio-economic issues along the Senegal River. The literature on multinational water crisis has for decades focused on mediation aspects of trans-boundary watershed management resulting in limited emphasis placed on the application of advances in geo-spatial information technologies in multinational watershed conservation in the arid areas of the West African sub-region within the Senegal River Basin for decision-making and monitoring. While the basin offers life support in a complex ecosystem that stretches across different nations in a mostly desert region characterized by water scarcity and subsistence economies, there exists recurrent environmental stress induced by both socio-economic and physical factors. Part of the problems consists of flooding, drought and limited access to sufficient quantities of water. These remain particularly sensitive issues that are crucial for the health of a rapidly growing population and the economy. The problems are further compounded due to the threats of climate change and the resultant degradation of almost the region's entire natural resources base. While the pace at which the institutional framework for managing the waters offers opportunities for hydro electricity and irrigated agriculture through the proliferation of dams, it has raised other serious concerns in the region. Even where data exists for confronting these issues, some of them are incompatible and dispersed among different agencies. This not only widens the geo-spatial data gaps, but it hinders the ability to monitor water problems along the basin. This study will fill that gap in research through mix scale methods built on descriptive statistics, GIS and remote sensing techniques by generating spatially referenced data to supplement

  20. Image segmentation: its application to information extraction for updating geo-spatial databases

    NASA Astrophysics Data System (ADS)

    Gu, Juan; Chen, Jun; Zhou, Qiming

    2005-10-01

    The unsatisfactory result of traditional pixel-based classification methods in classifying high resolution remotely sensed imagery may be improved by employing image segmentation. Based on a brief review of image segmentation, this paper introduces an image segmentation method--FNEA--which is used in eCognition, the first commercial object-oriented image processing software in the world, for automatic object extraction from high-resolution satellite images and automatic updating of GIS databases. From the point of information extraction, the author analyzes the advantages and disadvantages of the algorithm by using several examples and put forward possible improvements.

  1. Cancer diagnosis by nuclear morphometry using spatial information ☆,☆☆

    PubMed Central

    Huang, Hu; Tosun, Akif Burak; Guo, Jia; Chen, Cheng; Wang, Wei; Ozolek, John A.; Rohde, Gustavo K.

    2014-01-01

    Methods for extracting quantitative information regarding nuclear morphology from histopathology images have been long used to aid pathologists in determining the degree of differentiation in numerous malignancies. Most methods currently in use, however, employ the naïve Bayes approach to classify a set of nuclear measurements extracted from one patient. Hence, the statistical dependency between the samples (nuclear measurements) is often not directly taken into account. Here we describe a method that makes use of statistical dependency between samples in thyroid tissue to improve patient classification accuracies with respect to standard naïve Bayes approaches. We report results in two sample diagnostic challenges. PMID:24910485

  2. E-Learning in Photogrammetry, Remote Sensing and Spatial Information Science

    NASA Astrophysics Data System (ADS)

    Vyas, Anjana; König, Gerhard

    2016-06-01

    Science and technology are evolving leaps and bounds. The advancements in GI-Science for natural and built environment helps in improving the quality of life. Learning through education and training needs to be at par with those advancements, which plays a vital role in utilization of technology. New technologies that creates new opportunities have enabled Geomatics to broaden the horizon (skills and competencies). Government policies and decisions support the use of geospatial science in various sectors of governance. Mapping, Land management, Urban planning, Environmental planning, Industrialization are some of the areas where the geomatics has become a baseline for decision making at national level. There is a need to bridge the gap between developments in geospatial science and its utilization and implementation. To prepare a framework for standardisation it is important to understand the theories of education and prevailing practices, with articulate goals exploring variety of teaching techniques. E-Learning is an erudition practice shaped for facilitating learning and improving performance by creating, using and managing appropriate technological processes and resources through digital and network-enabled technology. It is a shift from traditional education or training to ICT-based flexible and collaborative learning based on the community of learners, academia, professionals, experts and facilitators. Developments in e-learning is focussed on computer assisted learning which has become popular because of its potential for providing more flexible access to content and instruction at any time, from any place (Means et al, 2009). With the advent of the geo-spatial technology, fast development in the software and hardware, the demand for skilled manpower is increasing and the need is for training, education, research and dissemination. It suggests inter-organisational cooperation between academia, industry, government and international collaboration. There is a

  3. Informing disease models with temporal and spatial contact structure among GPS-collared individuals in wild populations.

    PubMed

    Williams, David M; Dechen Quinn, Amy C; Porter, William F

    2014-01-01

    Contacts between hosts are essential for transmission of many infectious agents. Understanding how contacts, and thus transmission rates, occur in space and time is critical to effectively responding to disease outbreaks in free-ranging animal populations. Contacts between animals in the wild are often difficult to observe or measure directly. Instead, one must infer contacts from metrics such as proximity in space and time. Our objective was to examine how contacts between white-tailed deer (Odocoileus virginianus) vary in space and among seasons. We used GPS movement data from 71 deer in central New York State to quantify potential direct contacts between deer and indirect overlap in space use across time and space. Daily probabilities of direct contact decreased from winter (0.05-0.14), to low levels post-parturition through summer (0.00-0.02), and increased during the rut to winter levels. The cumulative distribution for the spatial structure of direct and indirect contact probabilities around a hypothetical point of occurrence increased rapidly with distance for deer pairs separated by 1,000 m-7,000 m. Ninety-five percent of the probabilities of direct contact occurred among deer pairs within 8,500 m of one another, and 99% within 10,900 m. Probabilities of indirect contact accumulated across greater spatial extents: 95% at 11,900 m and 99% at 49,000 m. Contacts were spatially consistent across seasons, indicating that although contact rates differ seasonally, they occur proportionally across similar landscape extents. Distributions of contact probabilities across space can inform management decisions for assessing risk and allocating resources in response. PMID:24409293

  4. Informing Disease Models with Temporal and Spatial Contact Structure among GPS-Collared Individuals in Wild Populations

    PubMed Central

    Williams, David M.; Dechen Quinn, Amy C.; Porter, William F.

    2014-01-01

    Contacts between hosts are essential for transmission of many infectious agents. Understanding how contacts, and thus transmission rates, occur in space and time is critical to effectively responding to disease outbreaks in free-ranging animal populations. Contacts between animals in the wild are often difficult to observe or measure directly. Instead, one must infer contacts from metrics such as proximity in space and time. Our objective was to examine how contacts between white-tailed deer (Odocoileus virginianus) vary in space and among seasons. We used GPS movement data from 71 deer in central New York State to quantify potential direct contacts between deer and indirect overlap in space use across time and space. Daily probabilities of direct contact decreased from winter (0.05–0.14), to low levels post-parturition through summer (0.00–0.02), and increased during the rut to winter levels. The cumulative distribution for the spatial structure of direct and indirect contact probabilities around a hypothetical point of occurrence increased rapidly with distance for deer pairs separated by 1,000 m – 7,000 m. Ninety-five percent of the probabilities of direct contact occurred among deer pairs within 8,500 m of one another, and 99% within 10,900 m. Probabilities of indirect contact accumulated across greater spatial extents: 95% at 11,900 m and 99% at 49,000 m. Contacts were spatially consistent across seasons, indicating that although contact rates differ seasonally, they occur proportionally across similar landscape extents. Distributions of contact probabilities across space can inform management decisions for assessing risk and allocating resources in response. PMID:24409293

  5. Estimating Regional Spatial and Temporal Variability of PM2.5 Concentrations Using Satellite Data, Meteorology, and Land Use Information

    PubMed Central

    Liu, Yang; Paciorek, Christopher J.; Koutrakis, Petros

    2009-01-01

    Background Studies of chronic health effects due to exposures to particulate matter with aerodynamic diameters ≤ 2.5 μm (PM2.5) are often limited by sparse measurements. Satellite aerosol remote sensing data may be used to extend PM2.5 ground networks to cover a much larger area. Objectives In this study we examined the benefits of using aerosol optical depth (AOD) retrieved by the Geostationary Operational Environmental Satellite (GOES) in conjunction with land use and meteorologic information to estimate ground-level PM2.5 concentrations. Methods We developed a two-stage generalized additive model (GAM) for U.S. Environmental Protection Agency PM2.5 concentrations in a domain centered in Massachusetts. The AOD model represents conditions when AOD retrieval is successful; the non-AOD model represents conditions when AOD is missing in the domain. Results The AOD model has a higher predicting power judged by adjusted R2 (0.79) than does the non-AOD model (0.48). The predicted PM2.5 concentrations by the AOD model are, on average, 0.8–0.9 μg/m3 higher than the non-AOD model predictions, with a more smooth spatial distribution, higher concentrations in rural areas, and the highest concentrations in areas other than major urban centers. Although AOD is a highly significant predictor of PM2.5, meteorologic parameters are major contributors to the better performance of the AOD model. Conclusions GOES aerosol/smoke product (GASP) AOD is able to summarize a set of weather and land use conditions that stratify PM2.5 concentrations into two different spatial patterns. Even if land use regression models do not include AOD as a predictor variable, two separate models should be fitted to account for different PM2.5 spatial patterns related to AOD availability. PMID:19590678

  6. Spatial cognition, body representation and affective processes: the role of vestibular information beyond ocular reflexes and control of posture

    PubMed Central

    Mast, Fred W.; Preuss, Nora; Hartmann, Matthias; Grabherr, Luzia

    2014-01-01

    A growing number of studies in humans demonstrate the involvement of vestibular information in tasks that are seemingly remote from well-known functions such as space constancy or postural control. In this review article we point out three emerging streams of research highlighting the importance of vestibular input: (1) Spatial Cognition: Modulation of vestibular signals can induce specific changes in spatial cognitive tasks like mental imagery and the processing of numbers. This has been shown in studies manipulating body orientation (changing the input from the otoliths), body rotation (changing the input from the semicircular canals), in clinical findings with vestibular patients, and in studies carried out in microgravity. There is also an effect in the reverse direction; top-down processes can affect perception of vestibular stimuli. (2) Body Representation: Numerous studies demonstrate that vestibular stimulation changes the representation of body parts, and sensitivity to tactile input or pain. Thus, the vestibular system plays an integral role in multisensory coordination of body representation. (3) Affective Processes and Disorders: Studies in psychiatric patients and patients with a vestibular disorder report a high comorbidity of vestibular dysfunctions and psychiatric symptoms. Recent studies investigated the beneficial effect of vestibular stimulation on psychiatric disorders, and how vestibular input can change mood and affect. These three emerging streams of research in vestibular science are—at least in part—associated with different neuronal core mechanisms. Spatial transformations draw on parietal areas, body representation is associated with somatosensory areas, and affective processes involve insular and cingulate cortices, all of which receive vestibular input. Even though a wide range of different vestibular cortical projection areas has been ascertained, their functionality still is scarcely understood. PMID:24904327

  7. The role of spatial information in the preservation of the shrimp nursery function of mangroves: a spatially explicit bio-economic model for the assessment of land use trade-offs.

    PubMed

    Zavalloni, Matteo; Groeneveld, Rolf A; van Zwieten, Paul A M

    2014-10-01

    Conversion to aquaculture affects the provision of important ecosystem services provided by mangrove ecosystems, and this effect depends strongly on the location of the conversion. We introduce in a bio-economic mathematical programming model relevant spatial elements that affect the provision of the nursery habitat service of mangroves: (1) direct or indirect connection of mangroves to watercourses; (2) the spatial allocation of aquaculture ponds; and (3) the presence of non-linear relations between mangrove extent and juvenile recruitment to wild shrimp populations. By tracing out the production possibilities frontier of wild and cultivated shrimp, the model assesses the role of spatial information in the trade-off between aquaculture and the nursery habitat function using spatial elements relevant to our model of a mangrove area in Ca Mau Province, Viet Nam. Results show that where mangrove forests have to coexist with shrimp aquaculture ponds, the inclusion of specific spatial information on ecosystem functions in considerations of land allocation can achieve aquaculture benefits while largely preserving the economic benefits generated by the nursery habitat function. However, if spatial criteria are ignored, ill-advised land allocation decisions can easily lead to a collapse of the mangrove's nursery function. PMID:24833524

  8. Approximate spatial reasoning

    NASA Technical Reports Server (NTRS)

    Dutta, Soumitra

    1988-01-01

    A model for approximate spatial reasoning using fuzzy logic to represent the uncertainty in the environment is presented. Algorithms are developed which can be used to reason about spatial information expressed in the form of approximate linguistic descriptions similar to the kind of spatial information processed by humans. Particular attention is given to static spatial reasoning.

  9. The design and implementation of urban police spatial decision support information systems based on COM GIS technology

    NASA Astrophysics Data System (ADS)

    Kun, Yang

    2006-10-01

    Based on a practical project and urban police professional work requirements, this paper has offered a solution for constructing the police spatial information decision support systems based on COM GIS technologies. According to the principles of software engineering, the systems development work contains the general system structure design, data requirements design, system function design, software interface design as well as the systems function realization methods. The main software technologies used in the systems development contain the spatial database, COM GIS, Web GIS, Oracle Objects for OLE (OO4O), and Police Decision Analysis Modeling technologies. In order to illustrate the basic principles and methods for the systems development, the realization process and relevant sample codes for crime case precaution function component has been described in the paper as an example for integrating GIS functions with police professional work models by using VC and VB developing tools. The realized systems function interfaces have also been offered in the paper for displaying the real effects of the systems. The development practice has proved that the COM GIS technology is very suitable for integrating police professional work models with GIS functions.

  10. Including land use information for the spatial estimation of groundwater quality parameters - 2. Interpolation methods, results, and comparison

    NASA Astrophysics Data System (ADS)

    Haslauer, C. P.; Heißerer, T.; Bárdossy, A.

    2016-04-01

    Two dominant processes determine solute concentration in groundwater: vertical infiltration and horizontal advection. The goal of this paper is to incorporate both processes into a geostatistical model for spatial estimation of solute concentrations in groundwater. A multivariate copula-based methodology is demonstrated that considers infiltration via the marginal distribution and solute transport via the multivariate spatial dependence structure. The novel approach is compared to traditional methods as Ordinary- and External Drift Kriging. Leave-one-out cross-validation demonstrates that the novel approach estimates better both in concentration and in probability space, and improves the quantification and quality of uncertainty. The gain in uncertainty reduction is equivalent to at least a few hundred additional observations when Ordinary Kriging was used. Both censored and not-censored measurements are included. An ideal neighborhood size is estimated via cross-validation. The methodology is general and can incorporate other kinds of secondary information. It can be used to evaluate effects of land use changes.

  11. Spatial accessibility of the population to urban health centres in Kermanshah, Islamic Republic of Iran: a geographic information systems analysis.

    PubMed

    Reshadat, S; Saedi, S; Zangeneh, A; Ghasemi, S R; Gilan, N R; Karbasi, A; Bavandpoor, E

    2015-06-01

    Geographic information systems (GIS) analysis has not been widely used in underdeveloped countries to ensure that vulnerable populations have accessibility to primary health-care services. This study applied GIS methods to analyse the spatial accessibility to urban primary-care centres of the population in Kermanshah city, Islamic Republic of Iran, by age and sex groups. In a descriptive-analytical study over 3 time periods, network analysis, mean centre and standard distance methods were applied using ArcGIS 9.3. The analysis was based on a standard radius of 750 m distance from health centres, walking speed of 1 m/s and desired access time to health centres of 12.5 mins. The proportion of the population with inadequate geographical access to health centres rose from 47.3% in 1997 to 58.4% in 2012. The mean centre and standard distance mapping showed that the spatial distribution of health centres in Kermanshah needed to be adjusted to changes in population distribution. PMID:26369997

  12. Geostatistics and Geographic Information Systems to Study the Spatial Distribution of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) in Peach Fields.

    PubMed

    Duarte, F; Calvo, M V; Borges, A; Scatoni, I B

    2015-08-01

    The oriental fruit moth, Grapholita molesta (Busck), is the most serious pest in peach, and several insecticide applications are required to reduce crop damage to acceptable levels. Geostatistics and Geographic Information Systems (GIS) are employed to measure the range of spatial correlation of G. molesta in order to define the optimum sampling distance for performing spatial analysis and to determine the current distribution of the pest in peach orchards of southern Uruguay. From 2007 to 2010, 135 pheromone traps per season were installed and georeferenced in peach orchards distributed over 50,000 ha. Male adult captures were recorded weekly from September to April. Structural analysis of the captures was performed, yielding 14 semivariograms for the accumulated captures analyzed by generation and growing season. Two sets of maps were constructed to describe the pest distribution. Nine significant models were obtained in the 14 evaluated periods. The range estimated for the correlation was from 908 to 6884 m. Three hot spots of high population level and some areas with comparatively low populations were constant over the 3-year period, while there is a greater variation in the size of the population in different generations and years in other areas. PMID:26174957

  13. Modelling hen harrier dynamics to inform human-wildlife conflict resolution: a spatially-realistic, individual-based approach.

    PubMed

    Heinonen, Johannes P M; Palmer, Stephen C F; Redpath, Steve M; Travis, Justin M J

    2014-01-01

    Individual-based models have gained popularity in ecology, and enable simultaneous incorporation of spatial explicitness and population dynamic processes to understand spatio-temporal patterns of populations. We introduce an individual-based model for understanding and predicting spatial hen harrier (Circus cyaneus) population dynamics in Great Britain. The model uses a landscape with habitat, prey and game management indices. The hen harrier population was initialised according to empirical census estimates for 1988/89 and simulated until 2030, and predictions for 1998, 2004 and 2010 were compared to empirical census estimates for respective years. The model produced a good qualitative match to overall trends between 1989 and 2010. Parameter explorations revealed relatively high elasticity in particular to demographic parameters such as juvenile male mortality. This highlights the need for robust parameter estimates from empirical research. There are clearly challenges for replication of real-world population trends, but this model provides a useful tool for increasing understanding of drivers of hen harrier dynamics and focusing research efforts in order to inform conflict management decisions. PMID:25405860

  14. Modelling Hen Harrier Dynamics to Inform Human-Wildlife Conflict Resolution: A Spatially-Realistic, Individual-Based Approach

    PubMed Central

    Heinonen, Johannes P. M.; Palmer, Stephen C. F.; Redpath, Steve M.; Travis, Justin M. J.

    2014-01-01

    Individual-based models have gained popularity in ecology, and enable simultaneous incorporation of spatial explicitness and population dynamic processes to understand spatio-temporal patterns of populations. We introduce an individual-based model for understanding and predicting spatial hen harrier (Circus cyaneus) population dynamics in Great Britain. The model uses a landscape with habitat, prey and game management indices. The hen harrier population was initialised according to empirical census estimates for 1988/89 and simulated until 2030, and predictions for 1998, 2004 and 2010 were compared to empirical census estimates for respective years. The model produced a good qualitative match to overall trends between 1989 and 2010. Parameter explorations revealed relatively high elasticity in particular to demographic parameters such as juvenile male mortality. This highlights the need for robust parameter estimates from empirical research. There are clearly challenges for replication of real-world population trends, but this model provides a useful tool for increasing understanding of drivers of hen harrier dynamics and focusing research efforts in order to inform conflict management decisions. PMID:25405860

  15. Combining qualitative and quantitative spatial and temporal information in a hierarchical structure: Approximate reasoning for plan execution monitoring

    NASA Technical Reports Server (NTRS)

    Hoebel, Louis J.

    1993-01-01

    The problem of plan generation (PG) and the problem of plan execution monitoring (PEM), including updating, queries, and resource-bounded replanning, have different reasoning and representation requirements. PEM requires the integration of qualitative and quantitative information. PEM is the receiving of data about the world in which a plan or agent is executing. The problem is to quickly determine the relevance of the data, the consistency of the data with respect to the expected effects, and if execution should continue. Only spatial and temporal aspects of the plan are addressed for relevance in this work. Current temporal reasoning systems are deficient in computational aspects or expressiveness. This work presents a hybrid qualitative and quantitative system that is fully expressive in its assertion language while offering certain computational efficiencies. In order to proceed, methods incorporating approximate reasoning using hierarchies, notions of locality, constraint expansion, and absolute parameters need be used and are shown to be useful for the anytime nature of PEM.

  16. Information Leakage Problem in Efficient Bidirectional Quantum Secure Direct Communication with Single Photons in Both Polarization and Spatial-Mode Degrees of Freedom

    NASA Astrophysics Data System (ADS)

    Liu, Zhi-Hao; Chen, Han-Wu; Liu, Wen-Jie

    2016-06-01

    The information leakage problem in the efficient bidirectional quantum secure direct communication protocol with single photons in both polarization and spatial-mode degrees of freedom is pointed out. Next, a way to revise this protocol to a truly secure one is given. We hope people pay more attention to the information leakage problem in order to design truly secure quantum communication protocols.

  17. Extracting Temporal and Spatial Distributions Information about Algal Glooms Based on Multitemporal Modis

    NASA Astrophysics Data System (ADS)

    Chunguang, L.; Qingjiu, T.

    2012-07-01

    Based on MODIS remote sensing data, method and technology to extraction the time and space distribution information of algae bloom is studied and established. The dynamic feature of time and space in Taihu Lake from 2009 to 2011 can be obtained by extracted method. Variation of cyanobacterial bloom in the Taihu Lake is analyzed and discussed. The algae bloom frequency index (AFI) and algae bloom sustainability index (ASI) is important criterion which can show the interannual and inter-monthly variation in the whole area or the subregion of Taihu Lake. Utilizing the AFI and ASI from 2009 to 2011, it found some phenomena that: the booming frequency decreased from the north and west to the East and South of Taihu Lake. The annual month algae bloom variation of AFI reflect the booming existing twin peaks in the high shock level and lag trend in general. In the subregion statistics, the IBD and ASI in 2011 show the abnormal condition in the border between the Gongshan Bay and Central Lake. The date is obvious earlier than that on the same subregion in previous years and that on others subregion in the same year.

  18. Gestalt grouping effects on tactile information processing: when touching hands override spatial proximity.

    PubMed

    Frings, Christian; Spence, Charles

    2013-04-01

    Using a tactile variant of the negative-priming paradigm, we analyzed the influence of Gestalt grouping on the ability of participants to ignore distracting tactile information. The distance between participants' hands, to which the target and distractor stimuli were simultaneously delivered, was varied (near/touching hands vs. hands far apart). In addition, the influence of touching hands was controlled, as participants wore gloves and their hands were blocked from vision by a cover. The magnitude of the tactile negative-priming effect was modulated by the interaction between hand separation and whether or not gloves were worn. When the hands were touching, negative priming emerged only while wearing gloves that prevented direct skin-to-skin contact. In contrast, when the separation between the participants' hands was larger, negative priming emerged only when gloves were not worn. This pattern of results is interpreted in terms of the competing influences of two interacting Gestalt principles--namely, connectedness and proximity--on the processing of tactile distractors. PMID:23307427

  19. Robust Point Sets Matching by Fusing Feature and Spatial Information Using Nonuniform Gaussian Mixture Models.

    PubMed

    Tao, Wenbing; Sun, Kun

    2015-11-01

    Most of the traditional methods that handle the point sets matching between two images are based on local feature descriptors and the succedent mismatch eliminating strategies, which usually suffers from the sparsity of the initial match set because some correct ambiguous associations are easily filtered out by the ratio test of SIFT matching due to their second ranking in feature similarity. In this paper, we propose a nonuniform Gaussian mixture model (NGMM) for point sets matching between a pair of images which combines feature with position information of the local feature points extracted from the image pair to achieve point sets matching in a GMM framework. The proposed point set matching using an NGMM is able to change the correspondence assignments throughout the matching process and has the potential to match up even ambiguous matches correctly. The proposed NGMM framework can be either used to directly find matches between two point sets obtained from two images or applied to remove outliers in a match set. When finding matches, NGMM tries to learn a nonrigid transformation between the two point sets and provide a probability for every found match to measure the reliability of the match. Then, a probability threshold can be used to get the final robust match set. When removing outliers, NGMM requires that the vector field formed by the correct matches to be coherent and the matches contradicting the coherent vector field will be regarded as mismatches to be removed. A number of comparison and evaluation experiments reveal the good performance of the proposed NGMM framework in both finding matches and discarding mismatches. PMID:26111398

  20. Development of an intelligent interface for adding spatial objects to a knowledge-based geographic information system

    NASA Technical Reports Server (NTRS)

    Campbell, William J.; Goettsche, Craig

    1989-01-01

    Earth Scientists lack adequate tools for quantifying complex relationships between existing data layers and studying and modeling the dynamic interactions of these data layers. There is a need for an earth systems tool to manipulate multi-layered, heterogeneous data sets that are spatially indexed, such as sensor imagery and maps, easily and intelligently in a single system. The system can access and manipulate data from multiple sensor sources, maps, and from a learned object hierarchy using an advanced knowledge-based geographical information system. A prototype Knowledge-Based Geographic Information System (KBGIS) was recently constructed. Many of the system internals are well developed, but the system lacks an adequate user interface. A methodology is described for developing an intelligent user interface and extending KBGIS to interconnect with existing NASA systems, such as imagery from the Land Analysis System (LAS), atmospheric data in Common Data Format (CDF), and visualization of complex data with the National Space Science Data Center Graphics System. This would allow NASA to quickly explore the utility of such a system, given the ability to transfer data in and out of KBGIS easily. The use and maintenance of the object hierarchies as polymorphic data types brings, to data management, a while new set of problems and issues, few of which have been explored above the prototype level.

  1. Spatial Analysis in Determination Of Flood Prone Areas Using Geographic Information System and Analytical Hierarchy Process at Sungai Sembrong's Catchment

    NASA Astrophysics Data System (ADS)

    Bukari, S. M.; Ahmad, M. A.; Wai, T. L.; Kaamin, M.; Alimin, N.

    2016-07-01

    Floods that struck Johor state in 2006 and 2007 and the East Coastal in 2014 have triggered a greatly impact to the flood management here in Malaysia. Accordingly, this study conducted to determine potential areas of flooding, especially in Batu Pahat district since it faces terrifying experienced with heavy flood. This objective is archived by using the application of Geographic Information Systems (GIS) on study area of flood risk location at the watershed area of Sungai Sembrong. GIS functions as spatial analysis is capable to produce new information based on analysis of data stored in the system. Meanwhile the Analytical Hierarchy Process (AHP) was used as a method for setting up in decision making concerning the existing data. By using AHP method, preparation and position of the criteria and parameters required in GIS are neater and easier to analyze. Through this study, a flood prone area in the watershed of Sungai Sembrong was identified with the help of GIS and AHP. Analysis was conducted to test two different cell sizes, which are 30 and 5. The analysis of flood prone areas were tested on both cell sizes with two different water levels and the results of the analysis were displayed by GIS. Therefore, the use of AHP and GIS are effective and able to determine the potential flood plain areas in the watershed area of Sungai Sembrong.

  2. Probability Mapping to Determine the Spatial Risk Pattern of Acute Gastroenteritis in Coimbatore District, India, Using Geographic Information Systems (GIS)

    PubMed Central

    Joseph, Pawlin Vasanthi; Balan, Brindha; Rajendran, Vidhyalakshmi; Prashanthi, Devi Marimuthu; Somnathan, Balasubramanian

    2015-01-01

    Background: Maps show well the spatial configuration of information. Considerable effort is devoted to the development of geographical information systems (GIS) that increase understanding of public health problems and in particular to collaborate efforts among clinicians, epidemiologists, ecologists, and geographers to map and forecast disease risk. Objectives: Small populations tend to give rise to the most extreme disease rates, even if the actual rates are similar across the areas. Such situations will follow the decision-maker's attention on these areas when they scrutinize the map for decision making or resource allocation. As an alternative, maps can be prepared using P-values (probabilistic values). Materials and Methods: The statistical significance of rates rather than the rates themselves are used to map the results. The incidence rates calculated for each village from 2000 to 2009 is used to estimate λ, the expected number of cases in the study area. The obtained results are mapped using Arc GIS 10.0. Results: The likelihood of infections from low to high is depicted in the map and it is observed that five villages namely, Odanthurai, Coimbatore Corporation, Ikkaraiboluvampatti, Puliakulam, and Pollachi Corporation are more likely to have significantly high incidences. Conclusion: In the probability map, some of the areas with exceptionally high or low rates disappear. These are typically small unpopulated areas, whose rates are unstable due to the small numbers problem. The probability map shows more specific regions of relative risks and expected outcomes. PMID:26170544

  3. On the use of a spatial cue as prior information for stereo sound source separation based on spatially weighted non-negative tensor factorization

    NASA Astrophysics Data System (ADS)

    Mitsufuji, Yuki; Roebel, Axel

    2014-12-01

    This paper proposes a new method to enhance the performance of non-negative tensor factorization (NTF), one of the most prevalent source separation techniques nowadays. The enhancement is mainly achieved by introducing weights on bin-wise NTF cost functions, which differentiates NTF target components from other components so that the target should be approximated more precisely than others. Assuming sources are distributed sparsely in a 2-D sound field, the target components approximating a target source are exclusively selected by a user, or from accompanying images by means of providing a spatial cue to an NTF framework. The spatial cue is given in a similar format to the well-known binaural feature, inter-channel level difference (IID). This helps incorporate the spatial cue into the system, since the similar features of this format can be easily calculated from every spectrogram bin. The weighting functions are designed taking into account the distance between the spatial cue and the calculated features. Namely, the largest values are assigned to the spectrogram bins where the features present the highest similarity to the spatial cue, and the value decreases in proportion to the distance between them. The method is evaluated in terms of separation quality, comparing the proposed algorithm to the conventional NTF technique, PARAFAC-NTF, as well as other source separation techniques. The evaluation results measured by the metric signal-to-distortion ratio (SDR), signal-to-interference ratio (SIR), and signal-to-artifact ratio (SAR) demonstrate the effectiveness of the new method, improved primarily by the weighting function and the initialization based on IID, while demonstrating a decrease in computational costs, a significant problem with NTF.

  4. Coarse-to-Fine Encoding of Spatial Frequency Information into Visual Short-Term Memory for Faces but Impartial Decay

    ERIC Educational Resources Information Center

    Gao, Zaifeng; Bentin, Shlomo

    2011-01-01

    Face perception studies investigated how spatial frequencies (SF) are extracted from retinal display while forming a perceptual representation, or their selective use during task-imposed categorization. Here we focused on the order of encoding low-spatial frequencies (LSF) and high-spatial frequencies (HSF) from perceptual representations into…

  5. Geographic Informations Systems and Pharmacoepidemiology: Using spatial cluster detection to monitor local patterns of prescription opioid abuse

    PubMed Central

    Brownstein, John S.; Green, Traci C.; Cassidy, Theresa A.; Butler, Stephen F.

    2010-01-01

    Purpose Understanding the spatial distribution of opioid abuse at the local level may facilitate public health interventions. Methods Using patient-level data from addiction treatment facilities in New Mexico from ASI-MV® Connect, we applied geographic information system in combination with a spatial scan statistics to generate risk maps of prescription opioid abuse and identify clusters of product- and compound-specific abuse. Prescribed opioid volume data was used to determine whether identified clusters are beyond geographic differences in availability. Results Data on 24,452 patients residing in New Mexico was collected. Among those patients, 1779 (7.3%) reported abusing any prescription opioid (past 30 days). According to opioid type, 979 patients (4.0%) reported abuse of any hydrocodone, 1007 (4.1%) for any oxycodone, 108 (0.4%) for morphine, 507 (2.1%) for Vicodin® or generic equivalent, 390 (1.6%) for OxyContin®, and 63 (0.2%) for MS Contin® or generic equivalent. Highest rates of abuse were found in the area surrounding Albuquerque with 8.6 patients indicating abuse per 100 interviewed patients. We found clustering of abuse around Albuquerque (P=0.001; Relative Risk=1.35 and a radius of 146 km). At the compound level, we found that drug availability was partly responsible for clustering of prescription opioid abuse. After accounting for drug availability, we identified a second foci of Vicodin® abuse in the southern rural portion of the state near Las Cruces, NM and El Paso, Texas and bordering Mexico (RR=2.1; P=0.001). Conclusions A better understanding of local risk distribution may have implications for response strategies to future introductions of prescription opioids. PMID:20535759

  6. Assessing habitat risk from human activities to inform coastal and marine spatial planning: a demonstration in Belize

    NASA Astrophysics Data System (ADS)

    Arkema, Katie K.; Verutes, Gregory; Bernhardt, Joanna R.; Clarke, Chantalle; Rosado, Samir; Canto, Maritza; Wood, Spencer A.; Ruckelshaus, Mary; Rosenthal, Amy; McField, Melanie; de Zegher, Joann

    2014-11-01

    Integrated coastal and ocean management requires transparent and accessible approaches for understanding the influence of human activities on marine environments. Here we introduce a model for assessing the combined risk to habitats from multiple ocean uses. We apply the model to coral reefs, mangrove forests and seagrass beds in Belize to inform the design of the country’s first Integrated Coastal Zone Management (ICZM) Plan. Based on extensive stakeholder engagement, review of existing legislation and data collected from diverse sources, we map the current distribution of coastal and ocean activities and develop three scenarios for zoning these activities in the future. We then estimate ecosystem risk under the current and three future scenarios. Current levels of risk vary spatially among the nine coastal planning regions in Belize. Empirical tests of the model are strong—three-quarters of the measured data for coral reef health lie within the 95% confidence interval of interpolated model data and 79% of the predicted mangrove occurrences are associated with observed responses. The future scenario that harmonizes conservation and development goals results in a 20% reduction in the area of high-risk habitat compared to the current scenario, while increasing the extent of several ocean uses. Our results are a component of the ICZM Plan for Belize that will undergo review by the national legislature in 2015. This application of our model to marine spatial planning in Belize illustrates an approach that can be used broadly by coastal and ocean planners to assess risk to habitats under current and future management scenarios.

  7. Anticipating Knowledge to Inform Species Management: Predicting Spatially Explicit Habitat Suitability of a Colonial Vulture Spreading Its Range

    PubMed Central

    Mateo-Tomás, Patricia; Olea, Pedro P.

    2010-01-01

    Background The knowledge of both potential distribution and habitat suitability is fundamental in spreading species to inform in advance management and conservation planning. After a severe decline in the past decades, the griffon vulture (Gyps fulvus) is now spreading its breeding range towards the northwest in Spain and Europe. Because of its key ecological function, anticipated spatial knowledge is required to inform appropriately both vulture and ecosystem management. Methodology/Findings Here we used maximum entropy (Maxent) models to determine the habitat suitability of potential and current breeding distribution of the griffon vulture using presence-only data (N = 124 colonies) in north-western Spain. The most relevant ecological factors shaping this habitat suitability were also identified. The resulting model had a high predictive performance and was able to predict species' historical distribution. 7.5% (∼1,850 km2) of the study area resulted to be suitable breeding habitat, most of which (∼70%) is already occupied by the species. Cliff availability and livestock density, especially of sheep and goats, around 10 km of the colonies were the fundamental factors determining breeding habitat suitability for this species. Conclusions/Significance Griffon vultures could still spread 50–60 km towards the west, increasing their breeding range in 1,782 km2. According to our results, 7.22% of the area suitable for griffon vulture will be affected by wind farms, so our results could help to better plan wind farm locations. The approach here developed could be useful to inform management of reintroductions and recovery programmes currently being implemented for both the griffon vulture and other threatened vulture species. PMID:20811501

  8. Decoding implicit information from the soil map of Belgium and implications for spatial modelling and soil classification

    NASA Astrophysics Data System (ADS)

    Dondeyne, Stefaan; Legrain, Xavier; Colinet, Gilles; Van Ranst, Eric; Deckers, Jozef

    2014-05-01

    (Anthrosols) are distinguished for their specific profile development (code "..m"). Obviously, when assessing soil organic carbon content these soil types need particular consideration. Soils in the Campine region with anthropogenic layers only 30 to 40 cm thick, not being Anthrosols, got a specific suffix code ("…3"). Still, as these soils may have a buried Ah horizon of up to 20 cm, their soil organic carbon content can be comparable to those of Anthrosols. The buried Ah horizon is however not explicitly mapped; its presence needs to be inferred from other environmental information. In conclusion, conventional soil maps convey more information than what transpires from just the explicit legend's semantics. Although a challenge, decoding the implicit information should be particularly useful for spatial modeling. The cases also point to the importance of classifying soil characteristics explicitly, wherever possible, and in particularly when soil maps are integrated into geographical information systems.

  9. Investigating the Potential of Using the Spatial and Spectral Information of Multispectral LiDAR for Object Classification.

    PubMed

    Gong, Wei; Sun, Jia; Shi, Shuo; Yang, Jian; Du, Lin; Zhu, Bo; Song, Shalei

    2015-01-01

    The abilities of multispectral LiDAR (MSL) as a new high-potential active instrument for remote sensing have not been fully revealed. This study demonstrates the potential of using the spectral and spatial features derived from a novel MSL to discriminate surface objects. Data acquired with the MSL include distance information and the intensities of four wavelengths at 556, 670, 700, and 780 nm channels. A support vector machine was used to classify diverse objects in the experimental scene into seven types: wall, ceramic pots, Cactaceae, carton, plastic foam block, and healthy and dead leaves of E. aureum. Different features were used during classification to compare the performance of different detection systems. The spectral backscattered reflectance of one wavelength and distance represented the features from an equivalent single-wavelength LiDAR system; reflectance of the four wavelengths represented the features from an equivalent multispectral image with four bands. Results showed that the overall accuracy of using MSL data was as high as 88.7%, this value was 9.8%-39.2% higher than those obtained using a single-wavelength LiDAR, and 4.2% higher than for multispectral image. PMID:26340630

  10. Prediction of hot spots in protein interfaces using extreme learning machines with the information of spatial neighbour residues.

    PubMed

    Wang, Lin; Zhang, Wenjuan; Gao, Qiang; Xiong, Congcong

    2014-08-01

    The identification of hot spots, a small subset of protein interfaces that accounts for the majority of binding free energy, is becoming increasingly important for the research on protein-protein interaction and drug design. For each interface residue or target residue to be predicted, the authors extract hybrid features which incorporate a wide range of information of the target residue and its spatial neighbor residues, that is, the nearest contact residue in the other face (mirror-contact residue) and the nearest contact residue in the same face (intra-contact residue). Here, feature selection is performed using random forests to avoid over-fitting. Thereafter, the extreme learning machine is employed to effectively integrate these hybrid features for predicting hot spots in protein interfaces. By the 5-fold cross validation in the training set, their method can achieve accuracy (ACC) of 82.1% and Matthew's correlation coefficient (MCC) of 0.459, and outperforms some alternative machine learning methods in the comparison study. Furthermore, their method achieves ACC of 76.8% and MCC of 0.401 in the independent test set, and is more effective than the major existing hot spot predictors. Their prediction method offers a powerful tool for uncovering candidate residues in the studies of alanine scanning mutagenesis for functional protein interaction sites. PMID:25075532

  11. Investigating the Potential of Using the Spatial and Spectral Information of Multispectral LiDAR for Object Classification

    PubMed Central

    Gong, Wei; Sun, Jia; Shi, Shuo; Yang, Jian; Du, Lin; Zhu, Bo; Song, Shalei

    2015-01-01

    The abilities of multispectral LiDAR (MSL) as a new high-potential active instrument for remote sensing have not been fully revealed. This study demonstrates the potential of using the spectral and spatial features derived from a novel MSL to discriminate surface objects. Data acquired with the MSL include distance information and the intensities of four wavelengths at 556, 670, 700, and 780 nm channels. A support vector machine was used to classify diverse objects in the experimental scene into seven types: wall, ceramic pots, Cactaceae, carton, plastic foam block, and healthy and dead leaves of E. aureum. Different features were used during classification to compare the performance of different detection systems. The spectral backscattered reflectance of one wavelength and distance represented the features from an equivalent single-wavelength LiDAR system; reflectance of the four wavelengths represented the features from an equivalent multispectral image with four bands. Results showed that the overall accuracy of using MSL data was as high as 88.7%, this value was 9.8%–39.2% higher than those obtained using a single-wavelength LiDAR, and 4.2% higher than for multispectral image. PMID:26340630

  12. When Distractors and To-Be-Remembered Items Compete for the Control of Action: A New Perspective on Serial Memory for Spatial Information

    ERIC Educational Resources Information Center

    Guerard, Katherine; Tremblay, Sebastien

    2011-01-01

    In serial memory for spatial information, performance is impaired when distractors are interpolated between to-be-remembered (TBR) stimuli (Tremblay, Nicholls, Parmentier, & Jones, 2005). The so-called sandwich effect, combined with the use of eye tracking, served as a tool for examining the role of the oculomotor system in serial memory for…

  13. The Implementation of a Geospatial Information Technology (GIT)-Supported Land Use Change Curriculum with Urban Middle School Learners to Promote Spatial Thinking

    ERIC Educational Resources Information Center

    Bodzin, Alec M.

    2011-01-01

    This study investigated whether a geospatial information technology (GIT)-supported science curriculum helped students in an urban middle school understand land use change (LUC) concepts and enhanced their spatial thinking. Five 8th grade earth and space science classes in an urban middle school consisting of three different ability level tracks…

  14. Lateralized Contribution of Prefrontal Cortex in Controlling Task-Irrelevant Information during Verbal and Spatial Working Memory Tasks: rTMS Evidence

    ERIC Educational Resources Information Center

    Sandrini, Marco; Rossini, Paolo Maria; Miniussi, Carlo

    2008-01-01

    The functional organization of working memory (WM) in the human prefrontal cortex remains unclear. The present study used repetitive transcranial magnetic stimulation (rTMS) to clarify the role of the dorsolateral prefrontal cortex (dlPFC) both in the types of information (verbal vs. spatial), and the types of processes (maintenance vs.…

  15. Integrating geospatial data and cropping system simulation within a geographic information system to analyze spatial seed cotton yield, water use, and irrigation requirements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development of sensors that provide geospatial information on crop and soil conditions has been a primary success for precision agriculture. However, further developments are needed to integrate geospatial data into computer algorithms that spatially optimize crop production while considering po...

  16. Prediction of seizure incidence probability in PTZ model of kindling through spatial learning ability in male and female rats.

    PubMed

    Haeri, Narges-Al-Sadat; Palizvan, Mohammad Reza; Sadegh, Mehdi; Aghaei, Zohre; Rafiei, Mohammad

    2016-07-01

    Epilepsy is a common neurological disease characterized by periodic seizures. Cognitive deficits and impairments in learning and memory are also associated with epilepsy. Neuronal changes and synaptic modifications in kindling model of epilepsy are similar to those occur during the learning procedure and memory formation. Herein we investigated whether seizure susceptibility in pentylenetetrazol (PTZ) model of kindling is predictable based on the learning ability in the Morris water maze (MWM) task in male and female rats. Allocentric learning was tested using MWM in present of light while egocentric learning was evaluated by MWM in dark room. The results indicated no significant differences in allocentric learning abilities between male and female rats. However, male rats were able to memorize the location of the platform more effectively compared to females in egocentric test. In addition, a statistically significant negative correlation between learning abilities (working memory) and seizure susceptibility in male rats was found while this correlation was positive in female rats. On the other hand, although there was no significant correlation between retrieval (reference memory) of spatial memories and seizure parameters in male rats, female rats showed a significant negative correlation. These findings may provide some evidences for prediction of seizure susceptibility according to learning ability and memory retention. PMID:27098273

  17. Improving urban land use and land cover classification from high-spatial-resolution hyperspectral imagery using contextual information

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this paper, we propose approaches to improve the pixel-based support vector machine (SVM) classification for urban land use and land cover (LULC) mapping from airborne hyperspectral imagery with high spatial resolution. Class spatial neighborhood relationship is used to correct the misclassified ...

  18. Place-Based Education and Geographic Information Systems: Enhancing the Spatial Awareness of Middle School Students in Maine

    ERIC Educational Resources Information Center

    Perkins, Nancy; Hazelton, Eric; Erickson, Jeryl; Allan, Walter

    2010-01-01

    Spatial literacy is a new frontier in K-12 education. This article describes a place-based introductory GIS/GPS middle school curriculum unit in which students used measuring tools, GPS units, and My World GIS software to collect physical and spatial data of trees to create a schoolyard tree inventory. Maine students completed "memory maps" of…

  19. Spatial Techniques

    NASA Astrophysics Data System (ADS)

    Jabeur, Nafaa; Sahli, Nabil

    The environment, including the Earth and the immense space, is recognized to be the main source of useful information for human beings. During several decades, the acquisition of data from this environment was constrained by tools and techniques with limited capabilities. However, thanks to continuous technological advances,spatial data are available in huge quantities for different applications. The technological advances have been achieved in terms of hardware and software as well. They are allowing for better accuracy and availability, which in turn improves the quality and quantity of useful knowledge that can be extracted from the environment. They have been applied to geography, resulting in geospatial techniques. Applied to both science and technology, geospatial techniques resulted in areas of expertise, such as land surveying, cartography, navigation, remote sensing, Geographic Infor-mation Systems (GISs), and Global Positioning Systems (GPSs). They had evolved quickly with advances in computing, satellite technology and a growing demand to understand our global environment. In this chapter, we will discuss three important techniques that are widely used in spatial data acquisition and analysis: GPS and remote sensing techniques that are used to collect spatial data and a GIS that is used to store, manipulate, analyze, and visualize spatial data. Later in this book, we will discuss the techniques that are currently available for spatial knowledge discovery.

  20. Seamless integration of data services between spatial information Grid and TeraGrid based on broker-based data management model

    NASA Astrophysics Data System (ADS)

    Zeng, Yi; Liu, Dingsheng; Li, Guoqing; Yu, Wenyang; Huang, Zhenchun; Song, Carol

    2009-10-01

    Most of the space agencies have built Grid systems to manage large volumes of spatial data archives and products. However, the heterogeneous data structure, the distributed storage location, and the gradual progress of building data service systems, make such spatial grid systems to be grid islands. The broker-based manage model can hide complexity and heterogeneity of spatial data sources, so that the research on broker-based data service is meaningful to promote inter-Grid collaboration for earth observation applications. This paper discusses the special problems of spatial information integration and some features of broker-based data management model. We demonstrate the prototype of building broker-based model to integrate heterogeneous data grid. This work securely provides querying and managing geospatial data and services, and transparent access to the related sources under Grid and Web Service environment. The paper also describe our experiences of case study on seamless integration with Purdue TeraGrid Data by using Storage Resource Broker, which is based on the extensible data service interfaces of China Spatial Information Grid.

  1. Mining spatial information to investigate the evolution of karst rocky desertification and its human driving forces in Changshun, China.

    PubMed

    Xu, Erqi; Zhang, Hongqi; Li, Mengxian

    2013-08-01

    The processes of karst rocky desertification (KRD) have been found to cause the most severe environmental degradation in southwestern China. Understanding the driving forces that cause KRD is essential for managing and restoring the areas that it impacts. Studies of the human driving forces of KRD are limited to the county level, a specific administrative unit in China; census data are acquired at this scale, which can lead to scale biases. Changshun County is studied here as a representative area and anthropogenic influences in the county are accounted for by using Euclidean distances for the proximity to roads and settlements. We propose a standard coefficient of human influence (SOI) that standardizes the Euclidean distances for different KRD transformations to compare the effects of human activities in different areas. In Changshun County, the individual influences of roads and settlements share similar characteristics. The SOIs of improved KRD transformation types are almost negative, but the SOIs of deteriorated types are nearly positive except for one form of KRD turning to the extremely severe KRD. The results indicated that the distribution and evolution of the KRD areas from 2000 to 2010 in Changshun were affected positively by human activities (e.g., KRD restoration projects) and also negatively (e.g., by intense and irrational land use). Our results demonstrate that the spatial techniques and SOI used in this study can effectively incorporate information concerning human influences and internal KRD transformations. This provides a suitable approach for studying the relationships between human activities and KRD processes at fine scales. PMID:23685367

  2. Using 2D correlation analysis to enhance spectral information available from highly spatially resolved AFM-IR spectra

    NASA Astrophysics Data System (ADS)

    Marcott, Curtis; Lo, Michael; Hu, Qichi; Kjoller, Kevin; Boskey, Adele; Noda, Isao

    2014-07-01

    The recent combination of atomic force microscopy and infrared spectroscopy (AFM-IR) has led to the ability to obtain IR spectra with nanoscale spatial resolution, nearly two orders-of-magnitude better than conventional Fourier transform infrared (FT-IR) microspectroscopy. This advanced methodology can lead to significantly sharper spectral features than are typically seen in conventional IR spectra of inhomogeneous materials, where a wider range of molecular environments are coaveraged by the larger sample cross section being probed. In this work, two-dimensional (2D) correlation analysis is used to examine position sensitive spectral variations in datasets of closely spaced AFM-IR spectra. This analysis can reveal new key insights, providing a better understanding of the new spectral information that was previously hidden under broader overlapped spectral features. Two examples of the utility of this new approach are presented. Two-dimensional correlation analysis of a set of AFM-IR spectra were collected at 200-nm increments along a line through a nucleation site generated by remelting a small spot on a thin film of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate). There are two different crystalline carbonyl band components near 1720 cm-1 that sequentially disappear before a band at 1740 cm-1 due to more disordered material appears. In the second example, 2D correlation analysis of a series of AFM-IR spectra spaced every 1 μm of a thin cross section of a bone sample measured outward from an osteon center of bone growth. There are many changes in the amide I and phosphate band contours, suggesting changes in the bone structure are occurring as the bone matures.

  3. Content-based image retrieval using spatial layout information in brain tumor T1-weighted contrast-enhanced MR images.

    PubMed

    Huang, Meiyan; Yang, Wei; Wu, Yao; Jiang, Jun; Gao, Yang; Chen, Yang; Feng, Qianjin; Chen, Wufan; Lu, Zhentai

    2014-01-01

    This study aims to develop content-based image retrieval (CBIR) system for the retrieval of T1-weighted contrast-enhanced MR (CE-MR) images of brain tumors. When a tumor region is fed to the CBIR system as a query, the system attempts to retrieve tumors of the same pathological category. The bag-of-visual-words (BoVW) model with partition learning is incorporated into the system to extract informative features for representing the image contents. Furthermore, a distance metric learning algorithm called the Rank Error-based Metric Learning (REML) is proposed to reduce the semantic gap between low-level visual features and high-level semantic concepts. The effectiveness of the proposed method is evaluated on a brain T1-weighted CE-MR dataset with three types of brain tumors (i.e., meningioma, glioma, and pituitary tumor). Using the BoVW model with partition learning, the mean average precision (mAP) of retrieval increases beyond 4.6% with the learned distance metrics compared with the spatial pyramid BoVW method. The distance metric learned by REML significantly outperforms three other existing distance metric learning methods in terms of mAP. The mAP of the CBIR system is as high as 91.8% using the proposed method, and the precision can reach 93.1% when the top 10 images are returned by the system. These preliminary results demonstrate that the proposed method is effective and feasible for the retrieval of brain tumors in T1-weighted CE-MR Images. PMID:25028970

  4. Transforming Spatial Reasoning Skills in the Upper-Level Undergraduate Geoscience Classroom Through Curricular Materials Informed by Cognitive Science Research

    NASA Astrophysics Data System (ADS)

    Ormand, C. J.; Shipley, T. F.; Dutrow, B. L.; Goodwin, L. B.; Hickson, T. A.; Tikoff, B.; Atit, K.; Gagnier, K. M.; Resnick, I.

    2014-12-01

    Spatial visualization is an essential skill in the STEM disciplines, including the geosciences. Undergraduate students, including geoscience majors in upper-level courses, bring a wide range of spatial skill levels to the classroom. Students with weak spatial skills may be unable to understand fundamental concepts and to solve geological problems with a spatial component. However, spatial thinking skills are malleable. As a group of geoscience faculty members and cognitive psychologists, we have developed a set of curricular materials for Mineralogy, Sedimentology & Stratigraphy, and Structural Geology courses. These materials are designed to improve students' spatial skills, and in particular to improve students' abilities to reason about spatially complex 3D geological concepts and problems. Teaching spatial thinking in the context of discipline-based exercises has the potential to transform undergraduate STEM education by removing one significant barrier to success in the STEM disciplines. The curricular materials we have developed are based on several promising teaching strategies that have emerged from cognitive science research on spatial thinking. These strategies include predictive sketching, making visual comparisons, gesturing, and the use of analogy. We have conducted a three-year study of the efficacy of these materials in strengthening the spatial skills of students in upper-level geoscience courses at three universities. Our methodology relies on a pre- and post-test study design, with several tests of spatial thinking skills administered at the beginning and end of each semester. In 2011-2012, we used a "business as usual" approach to gather baseline data, measuring how much students' spatial thinking skills improved in response to the existing curricula. In the two subsequent years we have incorporated our new curricular materials, which can be found on the project website: http://serc.carleton.edu/spatialworkbook/activities.html Structural Geology

  5. Micro and Macro Pattern Analyses of fMRI Data Support Both Early and Late Interaction of Numerical and Spatial Information

    PubMed Central

    Koten, Jan Willem; Lonnemann, Jan; Willmes, Klaus; Knops, André

    2011-01-01

    Numbers and space are two semantic primitives that interact with each other. Both recruit brain regions along the dorsal pathway, notably parietal cortex. This makes parietal cortex a candidate for the origin of numerical–spatial interaction. The underlying cognitive architecture of the interaction is still under scrutiny. Two classes of explanations can be distinguished. The early interaction approach assumes that numerical and spatial information are integrated into a single representation at a semantic level. A second approach postulates independent semantic representations. Only at the stage of response selection and preparation these two streams interact. In this study we used a numerical landmark task to identify the locus of the interaction between numbers and space. While lying in an MR scanner participants decided on the smaller of two numerical intervals in a visually presented number triplet. The spatial position of the middle number was varied; hence spatial intervals were congruent or incongruent with the numerical intervals. Responses in incongruent trials were slower and less accurate than in congruent trials. By combining across-vertex correlations (micro pattern) with a cluster analysis (macro pattern) we identified large-scale networks that were devoted to number processing, eye movements, and sensory–motor functions. Using support vector classification in different regions of interest along the intraparietal sulcus, the frontal eye fields, and supplementary motor area we were able to distinguish between congruent and incongruent trials in each of the networks. We suggest that the identified networks participate in the integration of numerical and spatial information and that the exclusive assumption of either an early or a late interaction between numerical and spatial information does not do justice to the complex interaction between both dimensions. PMID:22028688

  6. Information Leakage in Efficient Bidirectional Quantum Secure Direct Communication with Single Photons in Both Polarization and Spatial-Mode Degrees of Freedom

    NASA Astrophysics Data System (ADS)

    Zhang, Cai; Situ, Haozhen

    2016-06-01

    Recently, Wang et al. presented a bidirectional quantum secure direct communication protocol with single photons in both polarization and spatial-mode degrees of freedom (Int. J. Theor. Phys. 54(10): 3443-3453, 2015). They claimed that their protocol was efficient and removed the drawback of information leakage. However, we found that the information leakage actually exists in their protocol. In this paper, we analyze Wang et al.'s protocol in detail. In addition, we propose an improvement to avoid the information leakage. The security of the improved protocol has also been discussed.

  7. The Spatial Analysis on Hemorrhagic Fever with Renal Syndrome in Jiangsu Province, China Based on Geographic Information System

    PubMed Central

    Zhu, Yefei; Liu, Wendong; Hu, Jianli; Liang, Qi; Cheng, Yuejia; Wu, Ying; Yu, Rongbin; Zhou, Minghao; Shen, Hongbing; Chen, Feng; Tang, Fenyang; Peng, Zhihang

    2014-01-01

    Background Hemorrhagic fever with renal syndrome (HFRS) is endemic in mainland China, accounting for 90% of total reported cases worldwide, and Jiangsu is one of the most severely affected provinces. In this study, the authors conducted GIS-based spatial analyses in order to determine the spatial distribution of the HFRS cases, identify key areas and explore risk factors for public health planning and resource allocation. Methods Interpolation maps by inverse distance weighting were produced to detect the spatial distribution of HFRS cases in Jiangsu from 2001 to 2011. Spatio-temporal clustering was applied to identify clusters at the county level. Spatial correlation analysis was conducted to detect influencing factors of HFRS in Jiangsu. Results HFRS cases in Jiangsu from 2001 to 2011 were mapped and the results suggested that cases in Jiangsu were not distributed randomly. Cases were mainly distributed in northeastern and southwestern Jiangsu, especially in Dafeng and Sihong counties. It was notable that prior to this study, Sihong county had rarely been reported as a high-risk area of HFRS. With the maximum spatial size of 50% of the total population and the maximum temporal size of 50% of the total population, spatio-temporal clustering showed that there was one most likely cluster (LLR = 624.52, P<0.0001, RR = 8.19) and one second-most likely cluster (LLR = 553.97, P<0.0001, RR = 8.25), and both of these clusters appeared from 2001 to 2004. Spatial correlation analysis showed that the incidence of HFRS in Jiangsu was influenced by distances to highways, railways, rivers and lakes. Conclusion The application of GIS together with spatial interpolation, spatio-temporal clustering and spatial correlation analysis can effectively identify high-risk areas and factors influencing HFRS incidence to lay a foundation for researching its pathogenesis. PMID:25207806

  8. Spatial cognition through the keyhole: how studying a real-world domain can inform basic science--and vice versa.

    PubMed

    Keehner, Madeleine

    2011-10-01

    This paper discusses spatial cognition in the domain of minimally invasive surgery. It draws on studies from this domain to shed light on a range of spatial cognitive processes and to consider individual differences in performance. In relation to modeling, the aim is to identify potential opportunities for characterizing the complex interplay between perception, action, and cognition, and to consider how theoretical models of the relevant processes might prove valuable for addressing applied questions about surgical performance and training. PMID:25164502

  9. The orientation behaviour of the lesser spearnosed bat, Phyllostomus discolor (Chiroptera) in a model roost. Concurrence of visual, echoacoustical and endogenous spatial information.

    PubMed

    Höller, P; Schmidt, U

    1996-08-01

    The orientation behaviour of bats (Phyllostomus discolor, Phyllostomidae), flying inside an octagonal "roost-like" chamber (phi: 100 cm; h: 150 cm) was examined. It has been shown that the bats begin turning manoeuvres during flight by turning their head towards the direction they intend to proceed to. During early phases of the flights, cumulative navigation errors were evident, indicating that endogenous spatial information plays a major role in the orientation of the bats. During later phases of the flight this error is diminished again. So it can be concluded that the bats start to use exogenous spatial information for orientation while approaching the target. In order to investigate the relative importance of vision, echolocation and endogenous spatial information for approaching the roost, the landing lattices inside the test arena were changed for non-grid dummies. We found that: 1. combined visual and endogenous information are more important than echoacoustical cues, 2. the bats learned quickly to switch their orientation behaviour in order to get a better performance in avoiding the dummies, 3. the learning performance was influenced by the visual similarity of dummies and the real landing lattice. PMID:8765560

  10. Reference frames in virtual spatial navigation are viewpoint dependent

    PubMed Central

    Török, Ágoston; Nguyen, T. Peter; Kolozsvári, Orsolya; Buchanan, Robert J.; Nadasdy, Zoltan

    2014-01-01

    Spatial navigation in the mammalian brain relies on a cognitive map of the environment. Such cognitive maps enable us, for example, to take the optimal route from a given location to a known target. The formation of these maps is naturally influenced by our perception of the environment, meaning it is dependent on factors such as our viewpoint and choice of reference frame. Yet, it is unknown how these factors influence the construction of cognitive maps. Here, we evaluated how various combinations of viewpoints and reference frames affect subjects' performance when they navigated in a bounded virtual environment without landmarks. We measured both their path length and time efficiency and found that (1) ground perspective was associated with egocentric frame of reference, (2) aerial perspective was associated with allocentric frame of reference, (3) there was no appreciable performance difference between first and third person egocentric viewing positions and (4) while none of these effects were dependent on gender, males tended to perform better in general. Our study provides evidence that there are inherent associations between visual perspectives and cognitive reference frames. This result has implications about the mechanisms of path integration in the human brain and may also inspire designs of virtual reality applications. Lastly, we demonstrated the effective use of a tablet PC and spatial navigation tasks for studying spatial and cognitive aspects of human memory. PMID:25249956

  11. Electrophysiological correlates of top-down effects facilitating natural image categorization are disrupted by the attenuation of low spatial frequency information.

    PubMed

    Rokszin, Adrienn Aranka; Győri-Dani, Dóra; Nyúl, László G; Csifcsák, Gábor

    2016-02-01

    The modulatory effects of low and high spatial frequencies on the posterior C1, P1 and N1 event-related potential (ERP) amplitudes have long been known from previous electrophysiological studies. There is also evidence that categorization of complex natural images relies on top-down processes, probably by facilitating contextual associations during the recognition process. However, to our knowledge, no study has investigated so far how such top-down effects are manifested in scalp ERPs, when presenting natural images with attenuated low or high spatial frequency information. Twenty-one healthy subjects participated in an animal vs. vehicle categorization task with intact grayscale stimuli and images predominantly containing high (HSF) or low spatial frequencies (LSF). ERP scalp maps and amplitudes/latencies measured above occipital, parietal and frontocentral sites were compared among the three stimulus conditions. Although early occipital components (C1 and P1) were modulated by spatial frequencies, the time range of the N1 was the earliest to show top-down effects for images with unmodified low spatial frequency spectrum (intact and LSF stimuli). This manifested in ERP amplitude changes spreading to anterior scalp sites and shorter posterior N1 latencies. Finally, the frontocentral N350 and the centroparietal LPC were differently influenced by spatial frequency filtering, with the LPC being the only component to show an amplitude and latency modulation congruent with the behavioral responses (sensitivity index and reaction times). Our results strengthen the coarse-to-fine model of object recognition and provide electrophysiological evidence for low spatial frequency-based top-down effects within the first 200ms of visual processing. PMID:26707649

  12. Presentation of information for spatial decision support A survey on the use of maps by participants in quantitative water management in the IJsselmeer region, The Netherlands

    NASA Astrophysics Data System (ADS)

    Janssen, Ron; Uran, Oddrun

    Spatial decision support systems generate a diversity of information presented in tables, graphs, text and maps. Which form is used is dictated partially by the nature of the information but also by those who prepare information to be used in a decision-making process. The users of the information do not necessarily have the same preference for the way the information is presented. A survey has been conducted amongst stakeholders in a decision-making process to see what their preferences are. The purpose of the survey was to gain insight into the ability of stakeholders to use information presented at different levels of detail when comparing alternatives. This paper reports on the survey’s results. Possible relations between level of detail, the ease of use of information, confidence in correctness and value of the information are presented. The results show that maps and graphs are preferred above tables and text. A high preference for maps is, however, not a measure of the ability to use maps. In addition, the results show that even though the ability to use the information increased with decreasing level of detail, detailed information is found more valuable.

  13. A test of the role of two prefrontal/ subcortical networks in the "sequencing" of non-motor, visuo-spatial information.

    PubMed

    Tracy, Joseph I; La, Quan; Osipowicz, Karol; Mamtani, Anita; Schwartz, Daniel P; Uzelac, Giovanna

    2011-09-01

    There are a number of prefrontal/sub-cortical networks in the brain (e.g., cerebellar-thalamic-prefrontal or basal ganglia/supplementary motor cortex circuits) that despite having a clear role in motor function have been shown to be involved in non-motor tasks. In this project we test for the involvement of these networks in a dimensional judgment task that utilizes visual perceptual, visual spatial processing and requires the ordering of dimensional (height) information. Unlike previous studies examining non-motor sequencing, we directly compare both non-motor and motor versions of our dimensional judgment task. In addition, we examine activation uniquely associated with correct task responses. The findings provide evidence for the role of cortical not subcortical structures in the sequencing of visuo-spatial material apart from any motor output requirements. Our results suggest that the inferior parietal cortex (BA 7, 40) and medial frontal regions (BA 6, 8, 9 including the SMA) are instrumental to the task. Based on these results, we propose a prefrontal/parietal network plays a role in the implementation of a comparator mechanism that makes accurate comparisons along the dimension of interest, holds the information in working memory, and then (regardless of whether the information is correct or incorrect) generates a tag or abstract code that assigns the information a place in an ordered sequence. Most important, the information involved can be visual/symbolic and non-motor (not just motor) in nature. PMID:21503630

  14. Modeling Spatial Patterns of Soil Respiration in Maize Fields from Vegetation and Soil Property Factors with the Use of Remote Sensing and Geographical Information System

    PubMed Central

    Huang, Ni; Wang, Li; Guo, Yiqiang; Hao, Pengyu; Niu, Zheng

    2014-01-01

    To examine the method for estimating the spatial patterns of soil respiration (Rs) in agricultural ecosystems using remote sensing and geographical information system (GIS), Rs rates were measured at 53 sites during the peak growing season of maize in three counties in North China. Through Pearson's correlation analysis, leaf area index (LAI), canopy chlorophyll content, aboveground biomass, soil organic carbon (SOC) content, and soil total nitrogen content were selected as the factors that affected spatial variability in Rs during the peak growing season of maize. The use of a structural equation modeling approach revealed that only LAI and SOC content directly affected Rs. Meanwhile, other factors indirectly affected Rs through LAI and SOC content. When three greenness vegetation indices were extracted from an optical image of an environmental and disaster mitigation satellite in China, enhanced vegetation index (EVI) showed the best correlation with LAI and was thus used as a proxy for LAI to estimate Rs at the regional scale. The spatial distribution of SOC content was obtained by extrapolating the SOC content at the plot scale based on the kriging interpolation method in GIS. When data were pooled for 38 plots, a first-order exponential analysis indicated that approximately 73% of the spatial variability in Rs during the peak growing season of maize can be explained by EVI and SOC content. Further test analysis based on independent data from 15 plots showed that the simple exponential model had acceptable accuracy in estimating the spatial patterns of Rs in maize fields on the basis of remotely sensed EVI and GIS-interpolated SOC content, with R2 of 0.69 and root-mean-square error of 0.51 µmol CO2 m−2 s−1. The conclusions from this study provide valuable information for estimates of Rs during the peak growing season of maize in three counties in North China. PMID:25157827

  15. Modeling spatial patterns of soil respiration in maize fields from vegetation and soil property factors with the use of remote sensing and geographical information system.

    PubMed

    Huang, Ni; Wang, Li; Guo, Yiqiang; Hao, Pengyu; Niu, Zheng

    2014-01-01

    To examine the method for estimating the spatial patterns of soil respiration (Rs) in agricultural ecosystems using remote sensing and geographical information system (GIS), Rs rates were measured at 53 sites during the peak growing season of maize in three counties in North China. Through Pearson's correlation analysis, leaf area index (LAI), canopy chlorophyll content, aboveground biomass, soil organic carbon (SOC) content, and soil total nitrogen content were selected as the factors that affected spatial variability in Rs during the peak growing season of maize. The use of a structural equation modeling approach revealed that only LAI and SOC content directly affected Rs. Meanwhile, other factors indirectly affected Rs through LAI and SOC content. When three greenness vegetation indices were extracted from an optical image of an environmental and disaster mitigation satellite in China, enhanced vegetation index (EVI) showed the best correlation with LAI and was thus used as a proxy for LAI to estimate Rs at the regional scale. The spatial distribution of SOC content was obtained by extrapolating the SOC content at the plot scale based on the kriging interpolation method in GIS. When data were pooled for 38 plots, a first-order exponential analysis indicated that approximately 73% of the spatial variability in Rs during the peak growing season of maize can be explained by EVI and SOC content. Further test analysis based on independent data from 15 plots showed that the simple exponential model had acceptable accuracy in estimating the spatial patterns of Rs in maize fields on the basis of remotely sensed EVI and GIS-interpolated SOC content, with R2 of 0.69 and root-mean-square error of 0.51 µmol CO2 m(-2) s(-1). The conclusions from this study provide valuable information for estimates of Rs during the peak growing season of maize in three counties in North China. PMID:25157827

  16. Ecological Status of the St. Louis River System, as Informed by Spatially Comprehensive Surveys and Comparison to Coastal Wetlands Elsewhere

    EPA Science Inventory

    Extensive data on biota and the physical/chemical environment were collected across the lower St. Louis River in 2004-2007 as part of multiple studies undertaken by EPA. The 2005-2007 work provides a spatially highly-resolved assessment of conditions across the system, while the ...

  17. Joining up health and planning: how Joint Strategic Needs Assessment (JSNA) can inform health and wellbeing strategies and spatial planning.

    PubMed

    Tomlinson, Paul; Hewitt, Stephen; Blackshaw, Neil

    2013-09-01

    There has been a welcome joining up of the rhetoric around health, the environment and land use or spatial planning in both the English public health white paper and the National Planning Policy Framework. However, this paper highlights a real concern that this is not being followed through into practical guidance needed by local authorities (LAs), health bodies and developers about how to deliver this at the local level. The role of Joint Strategic Needs Assessments (JSNAs) and Health and Wellbeing Strategies (HWSs) have the potential to provide a strong basis for integrated local policies for health improvement, to address the wider determinants of health and to reduce inequities. However, the draft JSNA guidance from the Department of Health falls short of providing a robust, comprehensive and practical guide to meeting these very significant challenges. The paper identifies some examples of good practice. It recommends that action should be taken to raise the standards of all JSNAs to meet the new challenges and that HWSs should be aligned spatially and temporally with local plans and other LA strategies. HWSs should also identify spatially targeted interventions that can be delivered through spatial planning or transport planning. Steps need to be taken to ensure that district councils are brought into the process. PMID:23765329

  18. Effects of spatial resolution

    NASA Technical Reports Server (NTRS)

    Abrams, M.

    1982-01-01

    Studies of the effects of spatial resolution on extraction of geologic information are woefully lacking but spatial resolution effects can be examined as they influence two general categories: detection of spatial features per se; and the effects of IFOV on the definition of spectral signatures and on general mapping abilities.

  19. Spatial networks

    NASA Astrophysics Data System (ADS)

    Barthélemy, Marc

    2011-02-01

    Complex systems are very often organized under the form of networks where nodes and edges are embedded in space. Transportation and mobility networks, Internet, mobile phone networks, power grids, social and contact networks, and neural networks, are all examples where space is relevant and where topology alone does not contain all the information. Characterizing and understanding the structure and the evolution of spatial networks is thus crucial for many different fields, ranging from urbanism to epidemiology. An important consequence of space on networks is that there is a cost associated with the length of edges which in turn has dramatic effects on the topological structure of these networks. We will thoroughly explain the current state of our understanding of how the spatial constraints affect the structure and properties of these networks. We will review the most recent empirical observations and the most important models of spatial networks. We will also discuss various processes which take place on these spatial networks, such as phase transitions, random walks, synchronization, navigation, resilience, and disease spread.

  20. Spatial analysis of lymphatic filariasis distribution in the Nile Delta in relation to some environmental variables using geographic information system technology.

    PubMed

    Hassan, A N; Dister, S; Beck, L

    1998-04-01

    Geographic information system (GIS) was used to analyze the spatial distribution of filariasis in the Nile Delta. The study involved 201 villages belonging to Giza, Qalubiya, Monoufiya, Gharbiya, and Dakahliya governorates. Villages with similar microfilarial (mf) prevalence rates were observed to cluster within 1-2 km distance, then, clustering started to decrease significantly with distance up to 5 km (Pearson correlation coefficient = -0.98). the likelihood of negative and high prevalence villages being contiguous was very low (approximately 1.8%, n = 612 village-pairs) indicating homogeneity in disease processes within the defined spatial scales. Of the villages located within 2 km from the main Nile branches (n = 46), 95% exhibited low prevalence. In addition, the spatial pattern of mf prevalence was shown to be negatively associated with annual rainfall and relative humidity, while it was positively associated with annual daily temperature. Average mf prevalence in warmer, relatively drier areas receiving 25 mm of rain was significantly higher (3.9%) than that in less warmer but more humid areas receiving 50 mm of rain (1.6%) (P < 0.0001). Based on the results of the present study, GIS was used to generate a "filariasis risk map" that could be used by health authorities to efficiently direct surveillance and control efforts. This investigation identified some of the factors underlying filariasis spatial pattern, quantified clustering and demonstrated the potential of GIS application in vector-borne disease epidemiology. PMID:9617048

  1. Making the most of spatial information in health: a tutorial in Bayesian disease mapping for areal data.

    PubMed

    Kang, Su Yun; Cramb, Susanna M; White, Nicole M; Ball, Stephen J; Mengersen, Kerrie L

    2016-01-01

    Disease maps are effective tools for explaining and predicting patterns of disease outcomes across geographical space, identifying areas of potentially elevated risk, and formulating and validating aetiological hypotheses for a disease. Bayesian models have become a standard approach to disease mapping in recent decades. This article aims to provide a basic understanding of the key concepts involved in Bayesian disease mapping methods for areal data. It is anticipated that this will help in interpretation of published maps, and provide a useful starting point for anyone interested in running disease mapping methods for areal data. The article provides detailed motivation and descriptions on disease mapping methods by explaining the concepts, defining the technical terms, and illustrating the utility of disease mapping for epidemiological research by demonstrating various ways of visualising model outputs using a case study. The target audience includes spatial scientists in health and other fields, policy or decision makers, health geographers, spatial analysts, public health professionals, and epidemiologists. PMID:27245803

  2. Spatial distribution and accessibility to public sector tertiary care teaching hospitals in Karachi: A Geographic Information Systems application.

    PubMed

    Shaikh, Masood Ali; Ali, Mir Shabbar

    2016-07-01

    Optimal utilization of specialized curative healthcare services is contingent on spatial access to tertiary-care hospitals by the targeted population. The objectives of this study were to determine the spatial distribution of public sector tertiary-care teaching hospitals in Karachi, and to use GIS and network analysis for modeling the accessibility to these hospitals for Karachi residents. Maps of three, six, and nine kilometer buffers were created around the five selected hospitals to determine which towns of Karachi are either entirely or partially covered/accessible. Most of the towns in Karachi were covered either partially or completely by the three buffers and service areas of 3,6, and 9 kilometers around the five selected hospitals. This study highlights the limitations of using publicly available data for road network, and the need for creating and making available in public domain, comprehensive road network vector dataset in conjunction with population breakdowns by administrative subdivisions. PMID:27427142

  3. Spatial Patterns of Ischemic Heart Disease in Shenzhen, China: A Bayesian Multi-Disease Modelling Approach to Inform Health Planning Policies

    PubMed Central

    Du, Qingyun; Zhang, Mingxiao; Li, Yayan; Luan, Hui; Liang, Shi; Ren, Fu

    2016-01-01

    Incorporating the information of hypertension, this paper applies Bayesian multi-disease analysis to model the spatial patterns of Ischemic Heart Disease (IHD) risks. Patterns of harmful alcohol intake (HAI) and overweight/obesity are also modelled as they are common risk factors contributing to both IHD and hypertension. The hospitalization data of IHD and hypertension in 2012 were analyzed with three Bayesian multi-disease models at the sub-district level of Shenzhen. Results revealed that the IHD high-risk cluster shifted slightly north-eastward compared with the IHD Standardized Hospitalization Ratio (SHR). Spatial variations of overweight/obesity and HAI were found to contribute most to the IHD patterns. Identified patterns of IHD risk would benefit IHD integrated prevention. Spatial patterns of overweight/obesity and HAI could supplement the current disease surveillance system by providing information about small-area level risk factors, and thus benefit integrated prevention of related chronic diseases. Middle southern Shenzhen, where high risk of IHD, overweight/obesity, and HAI are present, should be prioritized for interventions, including alcohol control, innovative healthy diet toolkit distribution, insurance system revision, and community-based chronic disease intervention. Related health resource planning is also suggested to focus on these areas first. PMID:27104551

  4. Spatial Patterns of Ischemic Heart Disease in Shenzhen, China: A Bayesian Multi-Disease Modelling Approach to Inform Health Planning Policies.

    PubMed

    Du, Qingyun; Zhang, Mingxiao; Li, Yayan; Luan, Hui; Liang, Shi; Ren, Fu

    2016-04-01

    Incorporating the information of hypertension, this paper applies Bayesian multi-disease analysis to model the spatial patterns of Ischemic Heart Disease (IHD) risks. Patterns of harmful alcohol intake (HAI) and overweight/obesity are also modelled as they are common risk factors contributing to both IHD and hypertension. The hospitalization data of IHD and hypertension in 2012 were analyzed with three Bayesian multi-disease models at the sub-district level of Shenzhen. Results revealed that the IHD high-risk cluster shifted slightly north-eastward compared with the IHD Standardized Hospitalization Ratio (SHR). Spatial variations of overweight/obesity and HAI were found to contribute most to the IHD patterns. Identified patterns of IHD risk would benefit IHD integrated prevention. Spatial patterns of overweight/obesity and HAI could supplement the current disease surveillance system by providing information about small-area level risk factors, and thus benefit integrated prevention of related chronic diseases. Middle southern Shenzhen, where high risk of IHD, overweight/obesity, and HAI are present, should be prioritized for interventions, including alcohol control, innovative healthy diet toolkit distribution, insurance system revision, and community-based chronic disease intervention. Related health resource planning is also suggested to focus on these areas first. PMID:27104551

  5. Landfills in Jiangsu province, China, and potential threats for public health: Leachate appraisal and spatial analysis using geographic information system and remote sensing

    SciTech Connect

    Yang Kun; Zhou Xiaonong Yan Weian; Hang Derong; Steinmann, Peter

    2008-12-15

    Waste disposal is of growing environmental and public health concern in China where landfilling is the predominant method of disposal. The assessment of potential health hazards posed by existing landfills requires sound information, and processing of a significant amount of spatial data. Geographical information system (GIS) and remote sensing (RS) are valuable tools for assessing health impacts due to landfills. The aims of this study were: (i) to analyze the leachate and gas emissions from landfills used for domestic waste disposal in a metropolitan area of Jiangsu province, China, (ii) to investigate remotely-sensed environmental features in close proximity to landfills, and (iii) to evaluate the compliance of their location and leachate quality with the relevant national regulations. We randomly selected five landfills in the metropolitan areas of Wuxi and Suzhou city, Jiangsu province, established a GIS database and examined whether data were in compliance with national environmental and public health regulations. The leachates of the sampled landfills contained heavy metals (Pb, As, Cr{sup 6+} and Hg) and organic compounds in concentrations considered harmful to human health. Measured methane concentrations on landfill surfaces were low. Spatial analysis of the location of landfills with regard to distance from major water bodies, sensible infrastructure and environmental conditions according to current national legislation resulted in the rejection of four of the five sites as inappropriate for landfills. Our results call for rigorous evaluation of the spatial location of landfills in China that must take into consideration environmental and public health criteria.

  6. Landfills in Jiangsu province, China, and potential threats for public health: leachate appraisal and spatial analysis using geographic information system and remote sensing.

    PubMed

    Yang, Kun; Zhou, Xiao-Nong; Yan, Wei-An; Hang, De-Rong; Steinmann, Peter

    2008-12-01

    Waste disposal is of growing environmental and public health concern in China where landfilling is the predominant method of disposal. The assessment of potential health hazards posed by existing landfills requires sound information, and processing of a significant amount of spatial data. Geographical information system (GIS) and remote sensing (RS) are valuable tools for assessing health impacts due to landfills. The aims of this study were: (i) to analyze the leachate and gas emissions from landfills used for domestic waste disposal in a metropolitan area of Jiangsu province, China, (ii) to investigate remotely-sensed environmental features in close proximity to landfills, and (iii) to evaluate the compliance of their location and leachate quality with the relevant national regulations. We randomly selected five landfills in the metropolitan areas of Wuxi and Suzhou city, Jiangsu province, established a GIS database and examined whether data were in compliance with national environmental and public health regulations. The leachates of the sampled landfills contained heavy metals (Pb, As, Cr(6+) and Hg) and organic compounds in concentrations considered harmful to human health. Measured methane concentrations on landfill surfaces were low. Spatial analysis of the location of landfills with regard to distance from major water bodies, sensible infrastructure and environmental conditions according to current national legislation resulted in the rejection of four of the five sites as inappropriate for landfills. Our results call for rigorous evaluation of the spatial location of landfills in China that must take into consideration environmental and public health criteria. PMID:18396395

  7. The Importance of Temporal and Spatial Vegetation Structure Information in Biotope Mapping Schemes: A Case Study in Helsingborg, Sweden

    NASA Astrophysics Data System (ADS)

    Gao, Tian; Qiu, Ling; Hammer, Mårten; Gunnarsson, Allan

    2012-02-01

    Temporal and spatial vegetation structure has impact on biodiversity qualities. Yet, current schemes of biotope mapping do only to a limited extend incorporate these factors in the mapping. The purpose of this study is to evaluate the application of a modified biotope mapping scheme that includes temporal and spatial vegetation structure. A refined scheme was developed based on a biotope classification, and applied to a green structure system in Helsingborg city in southern Sweden. It includes four parameters of vegetation structure: continuity of forest cover, age of dominant trees, horizontal structure, and vertical structure. The major green structure sites were determined by interpretation of panchromatic aerial photographs assisted with a field survey. A set of biotope maps was constructed on the basis of each level of modified classification. An evaluation of the scheme included two aspects in particular: comparison of species richness between long-continuity and short-continuity forests based on identification of woodland continuity using ancient woodland indicators (AWI) species and related historical documents, and spatial distribution of animals in the green space in relation to vegetation structure. The results indicate that (1) the relationship between forest continuity: according to verification of historical documents, the richness of AWI species was higher in long-continuity forests; Simpson's diversity was significantly different between long- and short-continuity forests; the total species richness and Shannon's diversity were much higher in long-continuity forests shown a very significant difference. (2) The spatial vegetation structure and age of stands influence the richness and abundance of the avian fauna and rabbits, and distance to the nearest tree and shrub was a strong determinant of presence for these animal groups. It is concluded that continuity of forest cover, age of dominant trees, horizontal and vertical structures of vegetation

  8. Verbal Shadowing and Visual Interference in Spatial Memory

    PubMed Central

    Meilinger, Tobias; Bülthoff, Heinrich H.

    2013-01-01

    Spatial memory is thought to be organized along experienced views and allocentric reference axes. Memory access from different perspectives typically yields V-patterns for egocentric encoding (monotonic decline in performance along with the angular deviation from the experienced perspectives) and W-patterns for axes encoding (better performance along parallel and orthogonal perspectives than along oblique perspectives). We showed that learning an object array with a verbal secondary task reduced W-patterns compared with learning without verbal shadowing. This suggests that axes encoding happened in a verbal format; for example, by rows and columns. Alternatively, general cognitive load from the secondary task prevented memorizing relative to a spatial axis. Independent of encoding, pointing with a surrounding room visible yielded stronger W-patterns compared with pointing with no room visible. This suggests that the visible room geometry interfered with the memorized room geometry. With verbal shadowing and without visual interference only V-patterns remained; otherwise, V- and W-patterns were combined. Verbal encoding and visual interference explain when W-patterns can be expected alongside V-patterns and thus can help in resolving different performance patterns in a wide range of experiments. PMID:24019953

  9. The Impacts of Information-Sharing Mechanisms on Spatial Market Formation Based on Agent-Based Modeling

    PubMed Central

    Li, Qianqian; Yang, Tao; Zhao, Erbo; Xia, Xing’ang; Han, Zhangang

    2013-01-01

    There has been an increasing interest in the geographic aspects of economic development, exemplified by P. Krugman’s logical analysis. We show in this paper that the geographic aspects of economic development can be modeled using multi-agent systems that incorporate multiple underlying factors. The extent of information sharing is assumed to be a driving force that leads to economic geographic heterogeneity across locations without geographic advantages or disadvantages. We propose an agent-based market model that considers a spectrum of different information-sharing mechanisms: no information sharing, information sharing among friends and pheromone-like information sharing. Finally, we build a unified model that accommodates all three of these information-sharing mechanisms based on the number of friends who can share information. We find that the no information-sharing model does not yield large economic zones, and more information sharing can give rise to a power-law distribution of market size that corresponds to the stylized fact of city size and firm size distributions. The simulations show that this model is robust. This paper provides an alternative approach to studying economic geographic development, and this model could be used as a test bed to validate the detailed assumptions that regulate real economic agglomeration. PMID:23484007

  10. The impacts of information-sharing mechanisms on spatial market formation based on agent-based modeling.

    PubMed

    Li, Qianqian; Yang, Tao; Zhao, Erbo; Xia, Xing'ang; Han, Zhangang

    2013-01-01

    There has been an increasing interest in the geographic aspects of economic development, exemplified by P. Krugman's logical analysis. We show in this paper that the geographic aspects of economic development can be modeled using multi-agent systems that incorporate multiple underlying factors. The extent of information sharing is assumed to be a driving force that leads to economic geographic heterogeneity across locations without geographic advantages or disadvantages. We propose an agent-based market model that considers a spectrum of different information-sharing mechanisms: no information sharing, information sharing among friends and pheromone-like information sharing. Finally, we build a unified model that accommodates all three of these information-sharing mechanisms based on the number of friends who can share information. We find that the no information-sharing model does not yield large economic zones, and more information sharing can give rise to a power-law distribution of market size that corresponds to the stylized fact of city size and firm size distributions. The simulations show that this model is robust. This paper provides an alternative approach to studying economic geographic development, and this model could be used as a test bed to validate the detailed assumptions that regulate real economic agglomeration. PMID:23484007

  11. Dopamine Depletion In Either The Dorsomedial Or Dorsolateral Striatum Impairs Egocentric Cincinnati Water Maze Performance While Sparing Allocentric Morris Water Maze Learning

    PubMed Central

    Braun, Amanda A.; Amos-Kroohs, Robyn M.; Guetierez, Arnold; Lundgren, Kerstin H.; Seroogy, Kim B.; Skelton, Matthew R.; Vorhees, Charles V.; Williams, Michael T.

    2014-01-01

    Both egocentric route-based learning and spatial learning, as assessed by the Cincinnati water maze (CWM) and Morris water maze (MWM), respectively, are impaired following an 80% dopamine (DA) loss in the neostriatum after 6-hydroxydopamine (6-OHDA) administration in rats. The dorsolateral striatum (DLS) and the dorsomedial striatum (DMS) are implicated in different navigational learning types, namely the DLS is implicated in egocentric learning while the DMS is implicated in spatial learning. This experiment tested whether selective DA loss through 6-OHDA lesions in the DMS or DLS would impair one or both types of navigation. Both DLS and DMS DA loss significantly impaired route-based CWM learning, without affecting spatial or cued MWM performance. DLS 6-OHDA lesions produced a 75% DA loss in this region, with no changes in other monoamine levels in the DLS or DMS. DMS 6-OHDA lesions produced a 62% DA loss in this region, without affecting other monoamine levels in the DMS or DLS. The results indicate a role for DA in DLS and DMS regions in route-based egocentric but not spatial learning and memory. Spatial learning deficits may require more pervasive monoamine reductions within each region before deficits are exhibited. This is the first study to implicate DLS and DMS DA in route-based egocentric navigation. PMID:25451306

  12. Dopamine depletion in either the dorsomedial or dorsolateral striatum impairs egocentric Cincinnati water maze performance while sparing allocentric Morris water maze learning.

    PubMed

    Braun, Amanda A; Amos-Kroohs, Robyn M; Gutierrez, Arnold; Lundgren, Kerstin H; Seroogy, Kim B; Skelton, Matthew R; Vorhees, Charles V; Williams, Michael T

    2015-02-01

    Both egocentric route-based learning and spatial learning, as assessed by the Cincinnati water maze (CWM) and Morris water maze (MWM), respectively, are impaired following an 80% dopamine (DA) loss in the neostriatum after 6-hydroxydopamine (6-OHDA) administration in rats. The dorsolateral striatum (DLS) and the dorsomedial striatum (DMS) are implicated in different navigational learning types, namely the DLS is implicated in egocentric learning while the DMS is implicated in spatial learning. This experiment tested whether selective DA loss through 6-OHDA lesions in the DMS or DLS would impair one or both types of navigation. Both DLS and DMS DA loss significantly impaired route-based CWM learning, without affecting spatial or cued MWM performance. DLS 6-OHDA lesions produced a 75% DA loss in this region, with no changes in other monoamine levels in the DLS or DMS. DMS 6-OHDA lesions produced a 62% DA loss in this region, without affecting other monoamine levels in the DMS or DLS. The results indicate a role for DA in DLS and DMS regions in route-based egocentric but not spatial learning and memory. Spatial learning deficits may require more pervasive monoamine reductions within each region before deficits are exhibited. This is the first study to implicate DLS and DMS DA in route-based egocentric navigation. PMID:25451306

  13. The Contribution of Visual and Vestibular Information to Spatial Orientation by 6- to 14-Month-Old Infants and Adults

    ERIC Educational Resources Information Center

    Bremner, J. Gavin; Hatton, Fran; Foster, Kirsty A.; Mason, Uschi

    2011-01-01

    Although there is much research on infants' ability to orient in space, little is known regarding the information they use to do so. This research uses a rotating room to evaluate the relative contribution of visual and vestibular information to location of a target following bodily rotation. Adults responded precisely on the basis of visual flow…

  14. Combined administration of levetiracetam and valproic acid attenuates age-related hyperactivity of CA3 place cells, reduces place field area, and increases spatial information content in aged rat hippocampus.

    PubMed

    Robitsek, Jonathan; Ratner, Marcia H; Stewart, Tara; Eichenbaum, Howard; Farb, David H

    2015-12-01

    Learning and memory deficits associated with age-related mild cognitive impairment have long been attributed to impaired processing within the hippocampus. Hyperactivity within the hippocampal CA3 region that is associated with aging is mediated in part by a loss of functional inhibitory interneurons and thought to underlie impaired performance in spatial memory tasks, including the abnormal tendency in aged animals to pattern complete spatial representations. Here, we asked whether the spatial firing patterns of simultaneously recorded CA3 and CA1 neurons in young and aged rats could be manipulated pharmacologically to selectively reduce CA3 hyperactivity and thus, according to hypothesis, the associated abnormality in spatial representations. We used chronically implanted high-density tetrodes to record the spatial firing properties of CA3 and CA1 units during animal exploration for food in familiar and novel environments. Aged CA3 place cells have higher firing rates, larger place fields, less spatial information content, and respond less to a change from a familiar to a novel environment than young CA3 cells. We also find that the combination of levetiracetam (LEV) + valproic acid (VPA), previously shown to act as a cognitive enhancer in tests of spatial memory, attenuate CA3 place cell firing rates, reduce place field area, and increase spatial information content in aged but not young adult rats. This is consistent with drug enhancing the specificity of neuronal firing with respect to spatial location. Contrary to expectation, however, LEV + VPA reduces place cell discrimination between novel and familiar environments, i.e., spatial correlations increase, independent of age even though drug enhances performance in cognitive tasks. The results demonstrate that spatial information content, or the number of bits of information encoded per action potential, may be the key correlate for enhancement of spatial memory by LEV + VPA. PMID:25941121

  15. Feeling happy enhances early spatial encoding of peripheral information automatically: electrophysiological time-course and neural sources.

    PubMed

    Vanlessen, Naomi; Rossi, Valentina; De Raedt, Rudi; Pourtois, Gilles

    2014-09-01

    Previous research has shown that positive mood may broaden attention, although it remains unclear whether this effect has a perceptual or a postperceptual locus. In this study, we addressed this question using high-density event-related potential methods. We randomly assigned participants to a positive or a neutral mood condition. Then they performed a demanding oddball task at fixation (primary task ensuring fixation) and a localization task of peripheral stimuli shown at three positions in the upper visual field (secondary task) concurrently. While positive mood did not influence behavioral performance for the primary task, it did facilitate stimulus localization on the secondary task. At the electrophysiological level, we found that the amplitude of the C1 component (reflecting an early retinotopic encoding of the stimulus in V1) was enhanced in the positive, as compared with the neutral, mood group. Importantly, this effect appeared to be largely automatic, because it occurred regardless of the task relevance of the peripheral stimulus and prior to top-down gain control effects seen at the level of the subsequent P1 component. This early effect was also observed irrespective of a change of the target-related P300 component (primary task) by positive mood. These results suggest that positive mood can automatically boost the spatial encoding of peripheral stimuli early on following stimulus onset. This effect can eventually underlie the broadening of spatial attention, which has been associated with this specific mood state. PMID:24570275

  16. USING SPATIAL INFORMATION SYSTEM TECHNOLOGIES TO DETECT AND MAP WATERHYACINTH AND HYDRILLA INFESTATIONS IN THE RIO GRANDE RIVER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper describes a study conducted in 2002 on the application of aerial photography and videography, global positioning system (GPS), and geographic information system (GIS) technologies for detecting and mapping waterhyacinth [Eichhornia crassipes (Mort.) Solms] and hydrilla [Hydrilla verticill...

  17. Spatial query for decision support of cross-country movement. [in image-based geographic information system

    NASA Technical Reports Server (NTRS)

    Hepner, George F.; Logan, Thomas L.; Bryant, Nevin A.

    1988-01-01

    The use of a query language processor for decision support of cross-country movement in an image-based geographic information system is evaluated. It is found that query processing yields results which are comparable to those obtained using conventional cross-country movement techniques and analysis. Query processing also provides a flexibility of information extraction, rapid display, and flexible decision support in time-critical, limited data situations.

  18. The Development, Testing, and Use of a Computer Interface To Evaluate an Information Processing Model Describing the Rates of Encoding and Mental Rotation in High School Students of High and Low Spatial Ability.

    ERIC Educational Resources Information Center

    Donelson, Frederick Loye

    This study investigated the speed of encoding and rotation of images during simple spatial rotational operations to discover any similarities or differences in groups of differing spatial ability. This project was subdivided into five basic subproblems. First, research was done to arrive at a simple, easily testable information processing model…

  19. Towards a general framework for predicting threat status of data-deficient species from phylogenetic, spatial and environmental information

    PubMed Central

    Jetz, Walter; Freckleton, Robert P.

    2015-01-01

    In taxon-wide assessments of threat status many species remain not included owing to lack of data. Here, we present a novel spatial-phylogenetic statistical framework that uses a small set of readily available or derivable characteristics, including phylogenetically imputed body mass and remotely sensed human encroachment, to provide initial baseline predictions of threat status for data-deficient species. Applied to assessed mammal species worldwide, the approach effectively identifies threatened species and predicts the geographical variation in threat. For the 483 data-deficient species, the models predict highly elevated threat, with 69% ‘at-risk’ species in this set, compared with 22% among assessed species. This results in 331 additional potentially threatened mammals, with elevated conservation importance in rodents, bats and shrews, and countries like Colombia, Sulawesi and the Philippines. These findings demonstrate the future potential for combining phylogenies and remotely sensed data with species distributions to identify species and regions of conservation concern. PMID:25561677

  20. Informing Marine Spatial Planning (MSP) with numerical modelling: A case-study on shellfish aquaculture in Malpeque Bay (Eastern Canada).

    PubMed

    Filgueira, Ramón; Guyondet, Thomas; Bacher, Cédric; Comeau, Luc A

    2015-11-15

    A moratorium on further bivalve leasing was established in 1999-2000 in Prince Edward Island (Canada). Recently, a marine spatial planning process was initiated explore potential mussel culture expansion in Malpeque Bay. This study focuses on the effects of a projected expansion scenario on productivity of existing leases and available suspended food resources. The aim is to provide a robust scientific assessment using available datasets and three modelling approaches ranging in complexity: (1) a connectivity analysis among culture areas; (2) a scenario analysis of organic seston dynamics based on a simplified biogeochemical model; and (3) a scenario analysis of phytoplankton dynamics based on an ecosystem model. These complementary approaches suggest (1) new leases can affect existing culture both through direct connectivity and through bay-scale effects driven by the overall increase in mussel biomass, and (2) a net reduction of phytoplankton within the bounds of its natural variation in the area. PMID:26371845

  1. Spatial Distributions of HIV Infection in an Endemic Area of Western Kenya: Guiding Information for Localized HIV Control and Prevention.

    PubMed

    Hoshi, Tomonori; Fuji, Yoshito; Nzou, Samson Muuo; Tanigawa, Chihiro; Kiche, Ibrahim; Mwau, Matilu; Mwangi, Anne Wanjiru; Karama, Mohamed; Hirayama, Kenji; Goto, Kensuke; Kaneko, Satoshi

    2016-01-01

    HIV is still a major health problem in developing countries. Even though high HIV-risk-taking behaviors have been reported in African fishing villages, local distribution patterns of HIV infection in the communities surrounding these villages have not been thoroughly analyzed. The objective of this study was to investigate the geographical distribution patterns of HIV infection in communities surrounding African fishing villages. In 2011, we applied age- and sex-stratified random sampling to collect 1,957 blood samples from 42,617 individuals registered in the Health and Demographic Surveillance System in Mbita, which is located on the shore of Lake Victoria in western Kenya. We used these samples to evaluate existing antibody detection assays for several infectious diseases, including HIV antibody titers. Based on the results of the assays, we evaluated the prevalence of HIV infection according to sex, age, and altitude of participating households. We also used Kulldorff's spatial scan statistic to test for HIV clustering in the study area. The prevalence of HIV at our study site was 25.3%. Compared with the younger age group (15-19 years), adults aged 30-34 years were 6.71 times more likely to be HIV-positive, and the estimated HIV-positive population among women was 1.43 times larger than among men. Kulldorff's spatial scan statistic detected one marginally significant (P = 0.055) HIV-positive and one significant HIV-negative cluster (P = 0.047) in the study area. These results suggest a homogeneous HIV distribution in the communities surrounding fishing villages. In addition to individual behavior, more complex and diverse factors related to the social and cultural environment can contribute to a homogeneous distribution pattern of HIV infection outside of African fishing villages. To reduce rates of transmission in HIV-endemic areas, HIV prevention and control programs optimized for the local environment need to be developed. PMID:26862764

  2. Spatial Distributions of HIV Infection in an Endemic Area of Western Kenya: Guiding Information for Localized HIV Control and Prevention

    PubMed Central

    Hoshi, Tomonori; Fuji, Yoshito; Nzou, Samson Muuo; Tanigawa, Chihiro; Kiche, Ibrahim; Mwau, Matilu; Mwangi, Anne Wanjiru; Karama, Mohamed; Hirayama, Kenji; Goto, Kensuke; Kaneko, Satoshi

    2016-01-01

    HIV is still a major health problem in developing countries. Even though high HIV-risk-taking behaviors have been reported in African fishing villages, local distribution patterns of HIV infection in the communities surrounding these villages have not been thoroughly analyzed. The objective of this study was to investigate the geographical distribution patterns of HIV infection in communities surrounding African fishing villages. In 2011, we applied age- and sex-stratified random sampling to collect 1,957 blood samples from 42,617 individuals registered in the Health and Demographic Surveillance System in Mbita, which is located on the shore of Lake Victoria in western Kenya. We used these samples to evaluate existing antibody detection assays for several infectious diseases, including HIV antibody titers. Based on the results of the assays, we evaluated the prevalence of HIV infection according to sex, age, and altitude of participating households. We also used Kulldorff’s spatial scan statistic to test for HIV clustering in the study area. The prevalence of HIV at our study site was 25.3%. Compared with the younger age group (15–19 years), adults aged 30–34 years were 6.71 times more likely to be HIV-positive, and the estimated HIV-positive population among women was 1.43 times larger than among men. Kulldorff’s spatial scan statistic detected one marginally significant (P = 0.055) HIV-positive and one significant HIV-negative cluster (P = 0.047) in the study area. These results suggest a homogeneous HIV distribution in the communities surrounding fishing villages. In addition to individual behavior, more complex and diverse factors related to the social and cultural environment can contribute to a homogeneous distribution pattern of HIV infection outside of African fishing villages. To reduce rates of transmission in HIV-endemic areas, HIV prevention and control programs optimized for the local environment need to be developed. PMID:26862764

  3. Using Seabird Habitat Modeling to Inform Marine Spatial Planning in Central California’s National Marine Sanctuaries

    PubMed Central

    McGowan, Jennifer; Hines, Ellen; Elliott, Meredith; Howar, Julie; Dransfield, Andrea; Nur, Nadav; Jahncke, Jaime

    2013-01-01

    Understanding seabird habitat preferences is critical to future wildlife conservation and threat mitigation in California. The objective of this study was to investigate drivers of seabird habitat selection within the Gulf of the Farallones and Cordell Bank National Marine Sanctuaries to identify areas for targeted conservation planning. We used seabird abundance data collected by the Applied California Current Ecosystem Studies Program (ACCESS) from 2004–2011. We used zero-inflated negative binomial regression to model species abundance and distribution as a function of near surface ocean water properties, distances to geographic features and oceanographic climate indices to identify patterns in foraging habitat selection. We evaluated seasonal, inter-annual and species-specific variability of at-sea distributions for the five most abundant seabirds nesting on the Farallon Islands: western gull (Larus occidentalis), common murre (Uria aalge), Cassin’s auklet (Ptychorampus aleuticus), rhinoceros auklet (Cerorhinca monocerata) and Brandt’s cormorant (Phalacrocorax penicillatus). The waters in the vicinity of Cordell Bank and the continental shelf east of the Farallon Islands emerged as persistent and highly selected foraging areas across all species. Further, we conducted a spatial prioritization exercise to optimize seabird conservation areas with and without considering impacts of current human activities. We explored three conservation scenarios where 10, 30 and 50 percent of highly selected, species-specific foraging areas would be conserved. We compared and contrasted results in relation to existing marine protected areas (MPAs) and the future alternative energy footprint identified by the California Ocean Uses Atlas. Our results show that the majority of highly selected seabird habitat lies outside of state MPAs where threats from shipping, oil spills, and offshore energy development remain. This analysis accentuates the need for innovative marine

  4. Development of a spatial decision support system for flood risk management in Brazil that combines volunteered geographic information with wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Horita, Flávio E. A.; Albuquerque, João Porto de; Degrossi, Lívia C.; Mendiondo, Eduardo M.; Ueyama, Jó

    2015-07-01

    Effective flood risk management requires updated information to ensure that the correct decisions can be made. This can be provided by Wireless Sensor Networks (WSN) which are a low-cost means of collecting updated information about rivers. Another valuable resource is Volunteered Geographic Information (VGI) which is a comparatively new means of improving the coverage of monitored areas because it is able to supply supplementary information to the WSN and thus support decision-making in flood risk management. However, there still remains the problem of how to combine WSN data with VGI. In this paper, an attempt is made to investigate AGORA-DS, which is a Spatial Decision Support System (SDSS) that is able to make flood risk management more effective by combining these data sources, i.e. WSN with VGI. This approach is built over a conceptual model that complies with the interoperable standards laid down by the Open Geospatial Consortium (OGC) - e.g. Sensor Observation Service (SOS) and Web Feature Service (WFS) - and seeks to combine and present unified information in a web-based decision support tool. This work was deployed in a real scenario of flood risk management in the town of São Carlos in Brazil. The evidence obtained from this deployment confirmed that interoperable standards can support the integration of data from distinct data sources. In addition, they also show that VGI is able to provide information about areas of the river basin which lack data since there is no appropriate station in the area. Hence it provides a valuable support for the WSN data. It can thus be concluded that AGORA-DS is able to combine information provided by WSN and VGI, and provide useful information for supporting flood risk management.

  5. Visual perception of spatial relations in depth

    NASA Astrophysics Data System (ADS)

    Doumen, M. J. A.

    2006-09-01

    The visual perception of spatial relations of two objects was investigated in a series of experiments. We examined spatial and contextual parameters. The effect of spatial parameters was investigated with various two-dimensional tasks: an exocentric pointing task, a parallelity task and a collinearity task. Whereas spatial parameters like relative distance and visual angle influenced the settings of all observers in a similar way, there were differences between tasks in their dependence on different parameters. For example, whereas the settings of the other tasks were dependent on the relative distance the settings of the parallelity task were not. This can be explained by different task-demands that are specific for each of these tasks. In the exocentric pointing task an observer has to direct a pointer, with a remote control, towards a target. We expanded the exocentric pointing task to a three dimensional version in which the height was also varied. Therefore, we had two dependent variables: the deviations in the horizontal plane (slant) and in the vertical plane (tilt). With this extension of the task, we could conclude that visual space is anisotropic since in contrast to the slant the tilt was not dependent on the relative distance. Another three-dimensional task that has been used is the ball-in-plane task, a task in which the observer has to hang a ball in a plane defined by three other balls by adjusting it in height. We found settings that were best described as concave settings, which is in agreement with most conclusions of the work described above. Furthermore, we investigated the effects of context on the 3D exocentric pointing task. We tested whether the settings of the observer were dependent on an egocentric reference like frontoparallelity or an allocentric reference like parallelity to a wall. It turns out that people differ in the references they use to do the task. However, in another experiment, we concluded that a reference like one's own

  6. Cholinergic parameters and the retrieval of learned and re-learned spatial information: a study using a model of Wernicke-Korsakoff Syndrome.

    PubMed

    Pires, Rita G W; Pereira, Silvia R C; Oliveira-Silva, Ieda F; Franco, Glaura C; Ribeiro, Angela M

    2005-07-01

    This is a factorial (2 x 2 x 2) spatial memory and cholinergic parameters study in which the factors are chronic ethanol, thiamine deficiency and naivety in Morris water maze task. Both learning and retention of the spatial version of the water maze were assessed. To assess retrograde retention of spatial information, half of the rats were pre-trained on the maze before the treatment manipulations of pyrithiamine (PT)-induced thiamine deficiency and post-tested after treatment (pre-trained group). The other half of the animals was only trained after treatment to assess anterograde amnesia (post-trained group). Thiamine deficiency, associated to chronic ethanol treatment, had a significant deleterious effect on spatial memory performance of post-trained animals. The biochemical data revealed that chronic ethanol treatment reduced acetylcholinesterase (AChE) activity in the hippocampus while leaving the neocortex unchanged, whereas thiamine deficiency reduced both cortical and hippocampal AChE activity. Regarding basal and stimulated cortical acetylcholine (ACh) release, both chronic ethanol and thiamine deficiency treatments had significant main effects. Significant correlations were found between both cortical and hippocampal AChE activity and behaviour parameters for pre-trained but not for post-trained animals. Also for ACh release, the correlation found was significant only for pre-trained animals. These biochemical parameters were decreased by thiamine deficiency and chronic ethanol treatment, both in pre-trained and post-trained animals. But the correlation with the behavioural parameters was observed only for pre-trained animals, that is, those that were retrained and assessed for retrograde retention. PMID:15922063

  7. Spatial attention systems in spatial neglect.

    PubMed

    Karnath, Hans-Otto

    2015-08-01

    It has been established that processes relating to 'spatial attention' are implemented at cortical level by goal-directed (top-down) and stimulus-driven (bottom-up) networks. Spatial neglect in brain-damaged individuals has been interpreted as a distinguished exemplar for a disturbance of these processes. The present paper elaborates this assumption. Functioning of the two attentional networks seem to dissociate in spatial neglect; behavioral studies of patients' orienting and exploration behavior point to a disturbed stimulus-driven but preserved goal-directed attention system. When a target suddenly appears somewhere in space, neglect patients demonstrate disturbed detection and orienting if it is located in contralesional direction. In contrast, if neglect patients explore a scene with voluntarily, top-down controlled shifts of spatial attention, they perform movements that are oriented into all spatial directions without any direction-specific disturbances. The paper thus argues that not the top-down control of spatial attention itself, rather a body-related matrix on top of which this process is executed, seems affected. In that sense, the traditional role of spatial neglect as a stroke model for 'spatial attention' requires adjustment. Beyond its insights into the human stimulus-driven attentional system, the disorder most notably provides vistas in how our brain encodes topographical information and organizes spatially oriented action - including the top-down control of spatial attention - in relation to body position. PMID:26004064

  8. Spatial services grid

    NASA Astrophysics Data System (ADS)

    Cao, Jian; Li, Qi; Cheng, Jicheng

    2005-10-01

    This paper discusses the concept, key technologies and main application of Spatial Services Grid. The technologies of Grid computing and Webservice is playing a revolutionary role in studying the spatial information services. The concept of the SSG (Spatial Services Grid) is put forward based on the SIG (Spatial Information Grid) and OGSA (open grid service architecture). Firstly, the grid computing is reviewed and the key technologies of SIG and their main applications are reviewed. Secondly, the grid computing and three kinds of SIG (in broad sense)--SDG (spatial data grid), SIG (spatial information grid) and SSG (spatial services grid) and their relationships are proposed. Thirdly, the key technologies of the SSG (spatial services grid) is put forward. Finally, three representative applications of SSG (spatial services grid) are discussed. The first application is urban location based services gird, which is a typical spatial services grid and can be constructed on OGSA (Open Grid Services Architecture) and digital city platform. The second application is region sustainable development grid which is the key to the urban development. The third application is Region disaster and emergency management services grid.

  9. How Can Geographical Information Systems and Spatial Analysis Inform a Response to Prescription Opioid Misuse? A Discussion in the Context of Existing Literature.

    PubMed

    Mazumdar, Soumya; Mcrae, Ian S; Islam, M Mofizul

    2015-01-01

    The misuse of prescription opioids is a major public health problem in the United States, Canada, Australia and other parts of the developed world. Methods to quantify dimensions of the risk environment in relation to drug usage and law enforcement that are both structural and spatial, draw geography into traditional public health research even though there has been limited attempt to address the prescription opioid misuse problem from a geographic perspective. We discuss how geographic technologies can be utilized to study the landscape of prescription opioids and similar drugs, and target appropriate health services interventions. We use examples drawn from various jurisdictions to present our case and highlight through these examples how a geospatial perspective can help support research on prescription opioid misuse. The prescription drug misuse landscape can be studied through examination of the domains of demand, supply, harms and harm reduction. We discuss how each of these domains can benefit from a local geographic perspective, and subsequent geographic exploration and analyses. PMID:26452451

  10. Design and implementation of spatial knowledge grid for integrated spatial analysis

    NASA Astrophysics Data System (ADS)

    Liu, Xiangnan; Guan, Li; Wang, Ping

    2006-10-01

    Supported by spatial information grid(SIG), the spatial knowledge grid (SKG) for integrated spatial analysis utilizes the middleware technology in constructing the spatial information grid computation environment and spatial information service system, develops spatial entity oriented spatial data organization technology, carries out the profound computation of the spatial structure and spatial process pattern on the basis of Grid GIS infrastructure, spatial data grid and spatial information grid (specialized definition). At the same time, it realizes the complex spatial pattern expression and the spatial function process simulation by taking the spatial intelligent agent as the core to establish space initiative computation. Moreover through the establishment of virtual geographical environment with man-machine interactivity and blending, complex spatial modeling, network cooperation work and spatial community decision knowledge driven are achieved. The framework of SKG is discussed systematically in this paper. Its implement flow and the key technology with examples of overlay analysis are proposed as well.

  11. Language supports young children's use of spatial relations to remember locations.

    PubMed

    Miller, Hilary E; Patterson, Rebecca; Simmering, Vanessa R

    2016-05-01

    Two experiments investigated the role of language in children's spatial recall performance. In particular, we assessed whether selecting an intrinsic reference frame could be improved through verbal encoding. Selecting an intrinsic reference frame requires remembering locations relative to nearby objects independent of one's body (egocentric) or distal environmental (allocentric) cues, and does not reliably occur in children under 5 years of age (Nardini, Burgess, Breckenridge, & Atkinson, 2006). The current studies tested the relation between spatial language and 4-year-olds' selection of an intrinsic reference frame in spatial recall. Experiment 1 showed that providing 4-year-olds with location-descriptive cues during (Exp. 1a) or before (Exp. 1b) the recall task improved performance both overall and specifically on trials relying most on an intrinsic reference frame. Additionally, children's recall performance was predicted by their verbal descriptions of the task space (Exp. 1a control condition). Non-verbally highlighting relations among objects during the recall task (Exp. 2) supported children's performance relative to the control condition, but significantly less than the location-descriptive cues. These results suggest that the ability to verbally represent relations is a potential mechanism that could account for developmental changes in the selection of an intrinsic reference frame during spatial recall. PMID:26896902

  12. Synchronous imitation of continuous action sequences: The role of spatial and topological mapping.

    PubMed

    Ramenzoni, Verónica C; Sebanz, Natalie; Knoblich, Günther

    2015-10-01

    What are the mapping mechanisms that enable people to synchronously imitate continuous action sequences observed in others? We investigated this question in 4 experiments that used a tapping task where participants synchronously performed alternating bimanual hand movements with a model presented in an egocentric or allocentric orientation. Their task was to tap in synchrony, with each hand matching the movements of the ipsilateral model hand as closely as possible. The results show that automatic establishment of topological mappings, where the performer's hand is mapped onto the model's anatomically matching hand even if the 2 are spatially misaligned, can interfere with maintaining spatial mappings (Experiments 1 and 2). The interference was particularly strong in musicians who have expertise in establishing topological mappings in continuous performance (Experiment 4). Adopting an unusual body posture greatly interfered with establishing spatial as well as topological mappings (Experiment 3). Together, the results suggest that synchronous imitation of continuous action sequences depends on flexible predictive models that simultaneously apply spatial and topological mapping constraints to enable an actor to act in synchrony with observed action sequences. PMID:26052697

  13. Towards evidence-based, GIS-driven national spatial health information infrastructure and surveillance services in the United Kingdom

    PubMed Central

    Boulos, Maged N Kamel

    2004-01-01

    The term "Geographic Information Systems" (GIS) has been added to MeSH in 2003, a step reflecting the importance and growing use of GIS in health and healthcare research and practices. GIS have much more to offer than the obvious digital cartography (map) functions. From a community health perspective, GIS could potentially act as powerful evidence-based practice tools for early problem detection and solving. When properly used, GIS can: inform and educate (professionals and the public); empower decision-making at all levels; help in planning and tweaking clinically and cost-effective actions, in predicting outcomes before making any financial commitments and ascribing priorities in a climate of finite resources; change practices; and continually monitor and analyse changes, as well as sentinel events. Yet despite all these potentials for GIS, they remain under-utilised in the UK National Health Service (NHS). This paper has the following objectives: (1) to illustrate with practical, real-world scenarios and examples from the literature the different GIS methods and uses to improve community health and healthcare practices, e.g., for improving hospital bed availability, in community health and bioterrorism surveillance services, and in the latest SARS outbreak; (2) to discuss challenges and problems currently hindering the wide-scale adoption of GIS across the NHS; and (3) to identify the most important requirements and ingredients for addressing these challenges, and realising GIS potential within the NHS, guided by related initiatives worldwide. The ultimate goal is to illuminate the road towards implementing a comprehensive national, multi-agency spatio-temporal health information infrastructure functioning proactively in real time. The concepts and principles presented in this paper can be also applied in other countries, and on regional (e.g., European Union) and global levels. PMID:14748927

  14. A Bio-inspired Collision Avoidance Model Based on Spatial Information Derived from Motion Detectors Leads to Common Routes

    PubMed Central

    Bertrand, Olivier J. N.; Lindemann, Jens P.; Egelhaaf, Martin

    2015-01-01

    Avoiding collisions is one of the most basic needs of any mobile agent, both biological and technical, when searching around or aiming toward a goal. We propose a model of collision avoidance inspired by behavioral experiments on insects and by properties of optic flow on a spherical eye experienced during translation, and test the interaction of this model with goal-driven behavior. Insects, such as flies and bees, actively separate the rotational and translational optic flow components via behavior, i.e. by employing a saccadic strategy of flight and gaze control. Optic flow experienced during translation, i.e. during intersaccadic phases, contains information on the depth-structure of the environment, but this information is entangled with that on self-motion. Here, we propose a simple model to extract the depth structure from translational optic flow by using local properties of a spherical eye. On this basis, a motion direction of the agent is computed that ensures collision avoidance. Flying insects are thought to measure optic flow by correlation-type elementary motion detectors. Their responses depend, in addition to velocity, on the texture and contrast of objects and, thus, do not measure the velocity of objects veridically. Therefore, we initially used geometrically determined optic flow as input to a collision avoidance algorithm to show that depth information inferred from optic flow is sufficient to account for collision avoidance under closed-loop conditions. Then, the collision avoidance algorithm was tested with bio-inspired correlation-type elementary motion detectors in its input. Even then, the algorithm led successfully to collision avoidance and, in addition, replicated the characteristics of collision avoidance behavior of insects. Finally, the collision avoidance algorithm was combined with a goal direction and tested in cluttered environments. The simulated agent then showed goal-directed behavior reminiscent of components of the navigation

  15. Urban vegetation cover extraction from hyperspectral imagery and geographic information system spatial analysis techniques: case of Athens, Greece

    NASA Astrophysics Data System (ADS)

    Petropoulos, George P.; Kalivas, Dionissios P.; Georgopoulou, Iro A.; Srivastava, Prashant K.

    2015-01-01

    The present study aimed at evaluating the performance of two different pixel-based classifiers [spectral angle mapper (SAM) and support vector machines (SVMs)] in discriminating different land-cover classes in a typical urban setting, focusing particularly on urban vegetation cover by utilizing hyperspectral (EO-1 Hyperion) data. As a case study, the city of Athens, Greece, was used. Validation of urban vegetation predictions was based on the error matrix statistics. Additionally, the final urban vegetation cover maps were compared at a municipality level against reference urban vegetation cover estimates derived from the digitization of very high-resolution imagery. To ensure consistency and comparability of the results, the same training and validation points dataset were used to compare the different classifiers. The results showed that SVMs outperformed SAM in terms of both classification and urban vegetation cover mapping with an overall accuracy of 86.53% and Kappa coefficient 0.823, whereas for SAM classification, the accuracy statistics obtained were 75.13% and 0.673, respectively. Our results confirmed the ability of both techniques, when combined with Hyperion imagery, to extract urban vegetation cover for the case of a densely populated city with complex urban features, such as Athens. Our findings offer significant information at the local scale as regards to the presence of open green spaces in the urban environment of Athens. Such information is vital for successful infrastructure development, urban landscape planning, and improvement of urban environment. More widely, this study also contributes significantly toward an objective assessment of Hyperion in detecting and mapping urban vegetation cover.

  16. Geographic information systems (GIS) spatial data compilation of geodynamic, tectonic, metallogenic, mineral deposit, and geophysical maps and associated descriptive data for northeast Asia

    USGS Publications Warehouse

    Naumova, Vera V., (compiler); Patuk, Mikhail I.; Kapitanchuk, Marina Yu.; Nokleberg, Warren J.; Khanchuk, Alexander I.; Parfenov, Leonid M.; Rodionov, Sergey M.; Miller, Robert J.; Diggles, Michael F.

    2006-01-01

    This is the online version of a CD-ROM publication. It contains all of the data that are on the disc but extra files have been removed: index files, software installers, and Windows autolaunch files. The purpose of this publication is to provide a high-quality spatial data compilation (Geographical Information System or GIS) of geodynamic, mineral deposit, and metallogenic belt maps, and descriptive data for Northeast Asia for customers and users. This area consists of Eastern Siberia, Russian Far East, Mongolia, northern China, South Korea, and Japan. The GIS compilation contains integrated spatial data for: (1) a geodynamics map at a scale of 1:5,000,000; (2) a mineral deposit location map; (3) metallogenic belt maps; (4) detailed descriptions of geologic units, including tectonostratigraphic terranes, cratons, major melange zones, and overlap assemblages, with references; (5) detailed descriptions of metallogenic belts with references; (6) detailed mineral deposit descriptions with references; and (7) page-size stratigraphic columns for major terranes.

  17. Three-dimensional electromagnetic model-based scattering center matching method for synthetic aperture radar automatic target recognition by combining spatial and attributed information

    NASA Astrophysics Data System (ADS)

    Ma, Conghui; Wen, Gongjian; Ding, Boyuan; Zhong, JinRong; Yang, Xiaoliang

    2016-01-01

    A three-dimensional electromagnetic model (3-D EM-model)-based scattering center matching method is developed for synthetic aperture radar automatic target recognition (ATR). 3-D EM-model provides a concise and physically relevant description of the target's electromagnetic scattering phenomenon through its scattering centers which makes it an ideal candidate for ATR. In our method, scatters of the 3-D EM-model are projected to the two-dimensional measurement plane to predict scatters' location and scattering intensity properties. Then the identical information is extracted for scatters in measured data. A two-stage iterative operation is applied to match the model-predicted scatters and the measured data-extracted scatters by combining spatial and attributed information. Based on the two scatter sets' matching information, a similarity measurement between model and measured data is obtained and recognition conclusion is made. Meanwhile, the target's configuration is reasoned with 3-D EM-model serving as a reference. In the end, data simulated by electromagnetic computation verified this method's validity.

  18. Biomedical image representation approach using visualness and spatial information in a concept feature space for interactive region-of-interest-based retrieval.

    PubMed

    Rahman, Md Mahmudur; Antani, Sameer K; Demner-Fushman, Dina; Thoma, George R

    2015-10-01

    This article presents an approach to biomedical image retrieval by mapping image regions to local concepts where images are represented in a weighted entropy-based concept feature space. The term "concept" refers to perceptually distinguishable visual patches that are identified locally in image regions and can be mapped to a glossary of imaging terms. Further, the visual significance (e.g., visualness) of concepts is measured as the Shannon entropy of pixel values in image patches and is used to refine the feature vector. Moreover, the system can assist the user in interactively selecting a region-of-interest (ROI) and searching for similar image ROIs. Further, a spatial verification step is used as a postprocessing step to improve retrieval results based on location information. The hypothesis that such approaches would improve biomedical image retrieval is validated through experiments on two different data sets, which are collected from open access biomedical literature. PMID:26730398

  19. Spatial Visualizing in Children

    ERIC Educational Resources Information Center

    Smothergill, Daniel W.; And Others

    1975-01-01

    Reports four experiments with preschool and elementary school children. The first study involved a localization task and the remaining three required the mental manipulation of spatial information. (Author/SDH)

  20. Using a geographical information system for monitoring space shuttle launches: Determining cumulative distribution of deposition and an empirical test of a spatial model

    NASA Astrophysics Data System (ADS)

    Duncan, Brean W.; Schmalzer, Paul A.

    1994-05-01

    Space shuttle launches produce localized hydrochloric acid deposition. The interaction of solid rocket motor exhaust and deluge water released on the pad at the time of launch results in the formation of an exhaust cloud. The spatial pattern and extent of deposition from the launch cloud are predicted by the rocket exhaust effluent diffusion (REED) model. The actual pattern of deposition has been mapped by field surveys for each shuttle launch since 1981. In this paper we use a geographical information system (GIS) to compare model predictions with ground patterns for 49 shuttle launches. We also compile cumulative maps of deposition patterns needed to consider long-term impacts. The direction of launch cloud movement did not differ significantly from model predictions. The REED model overpredicted both the area that received deposition and the maximum distance from the launch pad that deposition occurred. Severe vegetation damage was restricted to near-field deposition areas within 1980 m north of each launch pad. Total area impacted from launches has been 87.0 ha around pad 39A and 52.9 ha around pad 39B. Far-field deposition has caused leaf spotting from acid droplets or aluminum oxide over a wider and more variable area than near-field. A total of 19,397 ha has received deposition, but 63.6% of this area has received deposition only one time and 92.2% not more than three times. GIS techniques provide means to test spatial models and compile information useful for assessing cumulative impacts.

  1. Using Geographic Information Systems and Spatial Analysis Methods to Assess Household Water Access and Sanitation Coverage in the SHINE Trial.

    PubMed

    Ntozini, Robert; Marks, Sara J; Mangwadu, Goldberg; Mbuya, Mduduzi N N; Gerema, Grace; Mutasa, Batsirai; Julian, Timothy R; Schwab, Kellogg J; Humphrey, Jean H; Zungu, Lindiwe I

    2015-12-15

    Access to water and sanitation are important determinants of behavioral responses to hygiene and sanitation interventions. We estimated cluster-specific water access and sanitation coverage to inform a constrained randomization technique in the SHINE trial. Technicians and engineers inspected all public access water sources to ascertain seasonality, function, and geospatial coordinates. Households and water sources were mapped using open-source geospatial software. The distance from each household to the nearest perennial, functional, protected water source was calculated, and for each cluster, the median distance and the proportion of households within <500 m and >1500 m of such a water source. Cluster-specific sanitation coverage was ascertained using a random sample of 13 households per cluster. These parameters were included as covariates in randomization to optimize balance in water and sanitation access across treatment arms at the start of the trial. The observed high variability between clusters in both parameters suggests that constraining on these factors was needed to reduce risk of bias. PMID:26602299

  2. Using Geographic Information Systems and Spatial Analysis Methods to Assess Household Water Access and Sanitation Coverage in the SHINE Trial

    PubMed Central

    Ntozini, Robert; Marks, Sara J.; Mangwadu, Goldberg; Mbuya, Mduduzi N. N.; Gerema, Grace; Mutasa, Batsirai; Julian, Timothy R.; Schwab, Kellogg J.; Humphrey, Jean H.; Zungu, Lindiwe I.

    2015-01-01

    Access to water and sanitation are important determinants of behavioral responses to hygiene and sanitation interventions. We estimated cluster-specific water access and sanitation coverage to inform a constrained randomization technique in the SHINE trial. Technicians and engineers inspected all public access water sources to ascertain seasonality, function, and geospatial coordinates. Households and water sources were mapped using open-source geospatial software. The distance from each household to the nearest perennial, functional, protected water source was calculated, and for each cluster, the median distance and the proportion of households within <500 m and >1500 m of such a water source. Cluster-specific sanitation coverage was ascertained using a random sample of 13 households per cluster. These parameters were included as covariates in randomization to optimize balance in water and sanitation access across treatment arms at the start of the trial. The observed high variability between clusters in both parameters suggests that constraining on these factors was needed to reduce risk of bias. PMID:26602299

  3. Uncertainty in the modelling of spatial and temporal patterns of shallow groundwater flow paths: The role of geological and hydrological site information

    NASA Astrophysics Data System (ADS)

    Woodward, Simon J. R.; Wöhling, Thomas; Stenger, Roland

    2016-03-01

    Understanding the hydrological and hydrogeochemical responses of hillslopes and other small scale groundwater systems requires mapping the velocity and direction of groundwater flow relative to the controlling subsurface material features. Since point observations of subsurface materials and groundwater head are often the basis for modelling these complex, dynamic, three-dimensional systems, considerable uncertainties are inevitable, but are rarely assessed. This study explored whether piezometric head data measured at high spatial and temporal resolution over six years at a hillslope research site provided sufficient information to determine the flow paths that transfer nitrate leached from the soil zone through the shallow saturated zone into a nearby wetland and stream. Transient groundwater flow paths were modelled using MODFLOW and MODPATH, with spatial patterns of hydraulic conductivity in the three material layers at the site being estimated by regularised pilot point calibration using PEST, constrained by slug test estimates of saturated hydraulic conductivity at several locations. Subsequent Null Space Monte Carlo uncertainty analysis showed that this data was not sufficient to definitively determine the spatial pattern of hydraulic conductivity at the site, although modelled water table dynamics matched the measured heads with acceptable accuracy in space and time. Particle tracking analysis predicted that the saturated flow direction was similar throughout the year as the water table rose and fell, but was not aligned with either the ground surface or subsurface material contours; indeed the subsurface material layers, having relatively similar hydraulic properties, appeared to have little effect on saturated water flow at the site. Flow path uncertainty analysis showed that, while accurate flow path direction or velocity could not be determined on the basis of the available head and slug test data alone, the origin of well water samples relative to the