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Sample records for working memory-a spatiotemporal

  1. Working memory: a proposal for child evaluating

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    Mayra Monteiro Pires

    2015-01-01

    Full Text Available The working memory is a system with limited capacity which allows the temporary storage and manipulation of information to cognitive complex abilities like language, learning and reasoning. This study has as the objective present the construction, the adaptation and the evaluation of four psycholinguistics working memory tests in Brazilian Portuguese that were based in the English battery of tests Memory Test Battery For Children. The tests adapted were applied in a pilot investigation in a group of 15 children with learning school difficulties and compared to a group of 15 children with normal development. The adaptation of the tests was developed in the E-Prime v2.0 Professional® software. The four psycholinguistic tests access the simultaneous storage and processing capacities of information in general domain, as also specific for language information. The results suggest that the four tests are sensible instruments to detect possible difficulties in the working memory processing in children, because they could identify the different performances between the two groups in a statistical analysis. The tests developed perfectly attended their aims for evaluation and can contribute in a near future for other studies with a greater number of subjects, providing a more concrete and evidences of working memory development in children.

  2. What works in auditory working memory? A neural oscillations perspective.

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    Wilsch, Anna; Obleser, Jonas

    2016-06-01

    Working memory is a limited resource: brains can only maintain small amounts of sensory input (memory load) over a brief period of time (memory decay). The dynamics of slow neural oscillations as recorded using magneto- and electroencephalography (M/EEG) provide a window into the neural mechanics of these limitations. Especially oscillations in the alpha range (8-13Hz) are a sensitive marker for memory load. Moreover, according to current models, the resultant working memory load is determined by the relative noise in the neural representation of maintained information. The auditory domain allows memory researchers to apply and test the concept of noise quite literally: Employing degraded stimulus acoustics increases memory load and, at the same time, allows assessing the cognitive resources required to process speech in noise in an ecologically valid and clinically relevant way. The present review first summarizes recent findings on neural oscillations, especially alpha power, and how they reflect memory load and memory decay in auditory working memory. The focus is specifically on memory load resulting from acoustic degradation. These findings are then contrasted with contextual factors that benefit neural as well as behavioral markers of memory performance, by reducing representational noise. We end on discussing the functional role of alpha power in auditory working memory and suggest extensions of the current methodological toolkit. This article is part of a Special Issue entitled SI: Auditory working memory. Published by Elsevier B.V.

  3. Raven's matrices and working memory: a dual-task approach.

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    Rao, K Venkata; Baddeley, Alan

    2013-01-01

    Raven's Matrices Test was developed as a "pure" measure of Spearman's concept of general intelligence, g. Subsequent research has attempted to specify the processes underpinning performance, some relating it to the concept of working memory and proposing a crucial role for the central executive, with the nature of other components currently unclear. Up to this point, virtually all work has been based on correlational analysis of number of correct solutions, sometimes related to possible strategies. We explore the application to this problem of the concurrent task methodology used widely in developing the concept of multicomponent working memory. Participants attempted to solve problems from the matrices under baseline conditions, or accompanied by backward counting or verbal repetition tasks, assumed to disrupt the central executive and phonological loop components of working memory, respectively. As in other uses of this method, number of items correct showed little effect, while solution time measures gave very clear evidence of an important role for the central executive, but no evidence for phonological loop involvement. We conclude that this and related concurrent task techniques hold considerable promise for the analysis of Raven's matrices and potentially for other established psychometric tests.

  4. The Endurance of Children's Working Memory: A Recall Time Analysis

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    Towse, John N.; Hitch, Graham J.; Hamilton, Z.; Pirrie, Sarah

    2008-01-01

    We analyze the timing of recall as a source of information about children's performance in complex working memory tasks. A group of 8-year-olds performed a traditional operation span task in which sequence length increased across trials and an operation period task in which processing requirements were extended across trials of constant sequence…

  5. Is Poor Working Memory a Transdiagnostic Risk Factor for Psychopathology?

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    Huang-Pollock, Cynthia; Shapiro, Zvi; Galloway-Long, Hilary; Weigard, Alex

    2017-11-01

    In contrast to historical conceptualizations that framed psychological disorders as distinct, categorical conditions, it is now widely understood that co- and multi-morbidities between disorders are extensive. As a result, there has been a call to better understand the dimensional liabilities that are common to and influence the development of multiple psychopathologies, as supported and exemplified by the National Institutes of Mental Health (NIMH) Research Domain Criteria (RDoC) framework. We use a latent variable SEM approach to examine the degree to which working memory deficits represent a cognitive liability associated with the development of common and discrete dimensions of psychopathology. In a sample of 415 community recruited children aged 8-12 (n = 170 girls), we fit a bi-factor model to parent reports of behavior from the DISC-4 and BASC-2, and included a latent working memory factor as a predictor of the internalizing, externalizing, and general "p-factor." We found that both the general "p-factor" and externalizing (but not internalizing) latent factor were significantly associated with working memory. When a bi-factor model of externalizing symptomology was fit to further explore this relationship, working memory was only correlated with the general externalizing dimension; correlation with specific inattention, hyperactive/impulsive, and oppositional factors did not survive once the general externalizing dimension was taken into consideration. These findings held regardless of the sex of the child. Our results suggest that working memory deficits represent both a common cognitive liability for mental health disorders, and a specific liability for externalizing disorders.

  6. Object Selection Costs in Visual Working Memory: A Diffusion Model Analysis of the Focus of Attention

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    Sewell, David K.; Lilburn, Simon D.; Smith, Philip L.

    2016-01-01

    A central question in working memory research concerns the degree to which information in working memory is accessible to other cognitive processes (e.g., decision-making). Theories assuming that the focus of attention can only store a single object at a time require the focus to orient to a target representation before further processing can…

  7. Does working memory training lead to generalized improvements in children with low working memory? A randomized controlled trial

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    Dunning, Darren L.; Holmes, Joni; Gathercole, Susan E.

    2013-01-01

    Children with low working memory typically make poor educational progress, and it has been speculated that difficulties in meeting the heavy working memory demands of the classroom may be a contributory factor. Intensive working memory training has been shown to boost performance on untrained memory tasks in a variety of populations. This first randomized controlled trial with low working memory children investigated whether the benefits of training extend beyond standard working memory tasks...

  8. Improving fluid intelligence with training on working memory: a meta-analysis

    National Research Council Canada - National Science Library

    Au, Jacky; Sheehan, Ellen; Tsai, Nancy; Duncan, Greg J; Buschkuehl, Martin; Jaeggi, Susanne M

    2015-01-01

    Working memory (WM), the ability to store and manipulate information for short periods of time, is an important predictor of scholastic aptitude and a critical bottleneck underlying higher-order cognitive processes...

  9. Does Working Memory Training Lead to Generalized Improvements in Children with Low Working Memory? A Randomized Controlled Trial

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    Dunning, Darren L.; Holmes, Joni; Gathercole, Susan E.

    2013-01-01

    Children with low working memory typically make poor educational progress, and it has been speculated that difficulties in meeting the heavy working memory demands of the classroom may be a contributory factor. Intensive working memory training has been shown to boost performance on untrained memory tasks in a variety of populations. This first…

  10. Sex differences in visual-spatial working memory: A meta-analysis.

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    Voyer, Daniel; Voyer, Susan D; Saint-Aubin, Jean

    2017-04-01

    Visual-spatial working memory measures are widely used in clinical and experimental settings. Furthermore, it has been argued that the male advantage in spatial abilities can be explained by a sex difference in visual-spatial working memory. Therefore, sex differences in visual-spatial working memory have important implication for research, theory, and practice, but they have yet to be quantified. The present meta-analysis quantified the magnitude of sex differences in visual-spatial working memory and examined variables that might moderate them. The analysis used a set of 180 effect sizes from healthy males and females drawn from 98 samples ranging in mean age from 3 to 86 years. Multilevel meta-analysis was used on the overall data set to account for non-independent effect sizes. The data also were analyzed in separate task subgroups by means of multilevel and mixed-effects models. Results showed a small but significant male advantage (mean d = 0.155, 95 % confidence interval = 0.087-0.223). All the tasks produced a male advantage, except for memory for location, where a female advantage emerged. Age of the participants was a significant moderator, indicating that sex differences in visual-spatial working memory appeared first in the 13-17 years age group. Removing memory for location tasks from the sample affected the pattern of significant moderators. The present results indicate a male advantage in visual-spatial working memory, although age and specific task modulate the magnitude and direction of the effects. Implications for clinical applications, cognitive model building, and experimental research are discussed.

  11. Gut Taste Stimulants Alter Brain Activity in Areas Related to Working Memory: a Pilot Study

    OpenAIRE

    Meyer-Gersprach Anne Christin; Suenderhauf Claudia; Bereiter Lukas; Zanchi Davide; Beglinger Christoph; Borgwardt Stefan; Wölnerkanssen Bettina K

    2016-01-01

    driving nutrient and energy intake as well as toxin avoidance. Taste receptors in the gastrointestinal tract might as well impact appetitive or aversive behavior and thus influence learning tasks and a close relation of neural taste processing and working memory networks seems plausible. Methods: In the present pilot study we determined the effects of five taste qualities “bitter” (quinine) “sweet” (glucose) “sour” (citric acid) “salty” (NaCl) and “umami” (monosodium glutamate MSG) on working...

  12. The effects of working memory resource availability on prospective memory: a formal modeling approach.

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    Smith, Rebekah E; Bayen, Ute J

    2005-01-01

    The PAM theory of event-based prospective memory (Smith, 2003; Smith & Bayen, 2004a) proposes that successful prospective memory performance demands upon the interaction of preparatory attentional processes and retrospective memory processes. The two experiments in the current study represent the first application of a formal model to investigate the sensitivity of these underlying processes to variations in working memory resource availability. Multinomial modeling of data from prospective-memory tasks showed that working memory span influenced preparatory attentional processes and retrospective-memory processes.

  13. The role of prefrontal cortex in working memory: a mini review

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    Antonio Homero Lara

    2015-12-01

    Full Text Available A prominent account of prefrontal cortex (PFC function is that single neurons within the PFC maintain representations of task-relevant stimuli in working memory. Evidence for this view comes from studies in which subjects hold a stimulus across a delay lasting up to several seconds. Persistent elevated activity in the PFC has been observed in animal models as well as in humans performing these tasks. This persistent activity has been interpreted as evidence for the encoding of the stimulus itself in working memory. However, recent findings have posed a challenge to this notion. A number of recent studies have examined neural data from the PFC and posterior sensory areas, both at the single neuron level in primates, and at a larger scale in humans, and have failed to find encoding of stimulus information in the PFC during tasks with a substantial working memory component. Strong stimulus related information, however, was seen in posterior sensory areas. These results suggest that delay period activity in the PFC might be better understood not as a signature of memory storage per se, but as a top down signal that influences posterior sensory areas where the actual working memory representations are maintained.

  14. When Spatial and Temporal Contiguities Help the Integration in Working Memory: "A Multimedia Learning" Approach

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    Mammarella, Nicola; Fairfield, Beth; Di Domenico, Alberto

    2013-01-01

    Two experiments examined the effects of spatial and temporal contiguities in a working memory binding task that required participants to remember coloured objects. In Experiment 1, a black and white drawing and a corresponding phrase that indicated its colour perceptually were either near or far (spatial study condition), while in Experiment 2,…

  15. Investigating the impact of mindfulness meditation training on working memory : A mathematical modeling approach

    NARCIS (Netherlands)

    van Vugt, Marieke K.; Jha, Amishi P.

    We investigated whether mindfulness training (MT) influences information processing in a working memory task with complex visual stimuli. Participants were tested before (T1) and after (T2) participation in an intensive one-month MT retreat, and their performance was compared with that of an age-

  16. Gut Taste Stimulants Alter Brain Activity in Areas Related to Working Memory: a Pilot Study.

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    Meyer-Gerspach, Anne Christin; Suenderhauf, Claudia; Bereiter, Lukas; Zanchi, Davide; Beglinger, Christoph; Borgwardt, Stefan; Wölnerhanssen, Bettina K

    2016-07-27

    Taste perception is one of the most important primary oral reinforcers, driving nutrient and energy intake as well as toxin avoidance. Taste receptors in the gastrointestinal tract might as well impact appetitive or aversive behavior and thus influence learning tasks and a close relation of neural taste processing and working memory networks seems plausible. In the present pilot study, we determined the effects of five taste qualities "bitter" (quinine), "sweet" (glucose), "sour" (citric acid), "salty" (NaCl) and "umami" (monosodium glutamate, MSG) on working memory processing using functional MRI and their effect on plasma insulin and glucose levels. On six separate occasions, subjects received one of the following test substances dissolved in 200 mL tap water via a nasogastric tube (to circumvent the oral cavity): 1) 2g citric acid corresponding to 52 mM, 2) 2g NaCl; 171 mM, 3) 0.017g quinine; 0.26 mM, 4) 1g monosodium glutamate; 30 mM, 5) 25g glucose; 694 mM and 6) 200 mL tap water (placebo). The taste qualities "bitter" and "umami" significantly altered brain activation patterns in the primary gustatory cortex as well as in subcortical structures, previously reported to be involved in emotional learning and memory. In contrast, glucose did not reveal any statistically significant brain activation difference. Working memory performance was not different over the six treatments. Plasma insulin and glucose levels were not affected by the different taste substances (MSG, quinine, NaCl and citric acid). in this pilot trial, we demonstrate that acute intragastric administration of different taste substances does not affect working memory performance in humans. However, "umami" and "bitter" have effects on brain areas involved in neural working memory, overpowering the effects of "sweet", "salty" and "sour" reception. © 2016 The Author(s) Published by S. Karger AG, Basel.

  17. Gut Taste Stimulants Alter Brain Activity in Areas Related to Working Memory: a Pilot Study

    OpenAIRE

    Anne Christin Meyer-Gerspach; Claudia Suenderhauf; Lukas Bereiter; Davide Zanchi; Christoph Beglinger; Stefan Borgwardt; Bettina K Wölnerhanssen

    2016-01-01

    Background/Aims: Taste perception is one of the most important primary oral reinforcers, driving nutrient and energy intake as well as toxin avoidance. Taste receptors in the gastrointestinal tract might as well impact appetitive or aversive behavior and thus influence learning tasks and a close relation of neural taste processing and working memory networks seems plausible. Methods: In the present pilot study, we determined the effects of five taste qualities “bitter” (quinine), “sweet” (glu...

  18. Caffeine differentially alters cortical hemodynamic activity during working memory: a near infrared spectroscopy study

    OpenAIRE

    Heilbronner, Urs; Hinrichs, Hermann; Heinze, Hans-Jochen; Zaehle, Tino

    2015-01-01

    Background Caffeine is a widely used stimulant with potentially beneficial effects on cognition as well as vasoconstrictive properties. In functional magnetic imaging research, caffeine has gained attention as a potential enhancer of the blood oxygenation level-dependent (BOLD) response. In order to clarify changes of oxy- and deoxyhemoglobin (HbO and HbR) induced by caffeine during a cognitive task, we investigated a working memory (WM) paradigm (visual 2-back) using near-infrared spectrosco...

  19. Effects of the menstrual cycle on language and visual working memory: a pilot study.

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    Konishi, Kiyomi; Kumashiro, Masaharu; Izumi, Hiroyuki; Higuchi, Yoshiyuki; Awa, Yayoi

    2009-10-01

    This study aimed to examine the effects on language and visual working memory of the follicle, luteal, and menstruation phases. The subjects were 12 female students. We added visual information and the assignment of experimental tasks, which requires the faculty of sight, to the previous study; therefore, this study has an index of visual and linguistic working memory. Computer-based tasks formulated by the authors, using the working memory that actively retains the information as the index, were used for experiments of 30 min during the follicle, luteal, and menstruation phases. After completion of the experiment of each phase, blood samples were collected in order to clearly distinguish the three phases of the subjects' menstrual cycle, and the session order was counter-balanced. The results showed that mental workload was higher in the luteal phase and stress was more easily felt. Indefinite complaints were most frequent during the menstruation phase, but task performance was good regardless of the indefinite complaint. It suggested that when the same tasks were performed during three phases, the sympathetic nerve was ascendant.

  20. Schooling, Local Knowledge and Working Memory: A Study among Three Contemporary Hunter-Gatherer Societies.

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    Victoria Reyes-García

    Full Text Available Researchers have analysed whether school and local knowledge complement or substitute each other, but have paid less attention to whether those two learning models use different cognitive strategies. In this study, we use data collected among three contemporary hunter-gatherer societies with relatively low levels of exposure to schooling yet with high levels of local ecological knowledge to test the association between i schooling and ii local ecological knowledge and verbal working memory. Participants include 94 people (24 Baka, 25 Punan, and 45 Tsimane' from whom we collected information on 1 schooling and school related skills (i.e., literacy and numeracy, 2 local knowledge and skills related to hunting and medicinal plants, and 3 working memory. To assess working memory, we applied a multi-trial free recall using words relevant to each cultural setting. People with and without schooling have similar levels of accurate and inaccurate recall, although they differ in their strategies to organize recall: people with schooling have higher results for serial clustering, suggesting better learning with repetition, whereas people without schooling have higher results for semantic clustering, suggesting they organize recall around semantically meaningful categories. Individual levels of local ecological knowledge are not related to accurate recall or organization recall, arguably due to overall high levels of local ecological knowledge. While schooling seems to favour some organization strategies this might come at the expense of some other organization strategies.

  1. Schooling, Local Knowledge and Working Memory: A Study among Three Contemporary Hunter-Gatherer Societies.

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    Reyes-García, Victoria; Pyhälä, Aili; Díaz-Reviriego, Isabel; Duda, Romain; Fernández-Llamazares, Álvaro; Gallois, Sandrine; Guèze, Maximilien; Napitupulu, Lucentezza

    2016-01-01

    Researchers have analysed whether school and local knowledge complement or substitute each other, but have paid less attention to whether those two learning models use different cognitive strategies. In this study, we use data collected among three contemporary hunter-gatherer societies with relatively low levels of exposure to schooling yet with high levels of local ecological knowledge to test the association between i) schooling and ii) local ecological knowledge and verbal working memory. Participants include 94 people (24 Baka, 25 Punan, and 45 Tsimane') from whom we collected information on 1) schooling and school related skills (i.e., literacy and numeracy), 2) local knowledge and skills related to hunting and medicinal plants, and 3) working memory. To assess working memory, we applied a multi-trial free recall using words relevant to each cultural setting. People with and without schooling have similar levels of accurate and inaccurate recall, although they differ in their strategies to organize recall: people with schooling have higher results for serial clustering, suggesting better learning with repetition, whereas people without schooling have higher results for semantic clustering, suggesting they organize recall around semantically meaningful categories. Individual levels of local ecological knowledge are not related to accurate recall or organization recall, arguably due to overall high levels of local ecological knowledge. While schooling seems to favour some organization strategies this might come at the expense of some other organization strategies.

  2. Gut Taste Stimulants Alter Brain Activity in Areas Related to Working Memory: a Pilot Study

    Directory of Open Access Journals (Sweden)

    Anne Christin Meyer-Gerspach

    2016-07-01

    Full Text Available Background/Aims: Taste perception is one of the most important primary oral reinforcers, driving nutrient and energy intake as well as toxin avoidance. Taste receptors in the gastrointestinal tract might as well impact appetitive or aversive behavior and thus influence learning tasks and a close relation of neural taste processing and working memory networks seems plausible. Methods: In the present pilot study, we determined the effects of five taste qualities “bitter” (quinine, “sweet” (glucose, “sour” (citric acid, “salty” (NaCl and “umami” (monosodium glutamate, MSG on working memory processing using functional MRI and their effect on plasma insulin and glucose levels. On six separate occasions, subjects received one of the following test substances dissolved in 200 mL tap water via a nasogastric tube (to circumvent the oral cavity: 1 2g citric acid corresponding to 52 mM, 2 2g NaCl; 171 mM, 3 0.017g quinine; 0.26 mM, 4 1g monosodium glutamate; 30 mM, 5 25g glucose; 694 mM and 6 200 mL tap water (placebo. Results: The taste qualities “bitter” and “umami” significantly altered brain activation patterns in the primary gustatory cortex as well as in subcortical structures, previously reported to be involved in emotional learning and memory. In contrast, glucose did not reveal any statistically significant brain activation difference. Working memory performance was not different over the six treatments. Plasma insulin and glucose levels were not affected by the different taste substances (MSG, quinine, NaCl and citric acid. Conclusions: in this pilot trial, we demonstrate that acute intragastric administration of different taste substances does not affect working memory performance in humans. However, “umami” and “bitter” have effects on brain areas involved in neural working memory, overpowering the effects of “sweet”, “salty” and “sour” reception.

  3. Effects of electromagnetic fields emitted by GSM phones on working memory: a meta-analysis.

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    Zubko, O; Gould, R L; Gay, H C; Cox, H J; Coulson, M C; Howard, R J

    2017-02-01

    Current treatments for Alzheimer's Disease (AD) do not affect the course of the illness and brain stimulation techniques are increasingly promoted as potential therapeutic interventions for AD. This study reviews the effects of electromagnetic field (EMF) exposure versus sham exposure on working memory (WM) performance of healthy human participants. Online literature databases and previous systematic reviews were searched for studies of EMF and WM in participants without reported memory problems. Two thousand eight hundred and fifty seven studies were identified, and 10 studies met the inclusion criteria. An assessment of study quality was completed, and separate, random effects meta-analyses were conducted for each of the three WM tasks included: n-back, substitution and digit span forward. No differences were found between participants exposed to active EMF versus sham conditions in any of the three working memory tasks examined. Results indicate that EMF does not affect WM during the n-back, substitution and digit-span tasks. Future studies should focus on the possible effects of chronic exposure to EMF in older adults with AD using a battery of comparable WM and attention tasks, before EMF can be seriously considered as a potential modulator of WM in AD. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  4. User requirements for geo-collaborative work with spatio-temporal data in a web-based virtual globe environment.

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    Yovcheva, Zornitza; van Elzakker, Corné P J M; Köbben, Barend

    2013-11-01

    Web-based tools developed in the last couple of years offer unique opportunities to effectively support scientists in their effort to collaborate. Communication among environmental researchers often involves not only work with geographical (spatial), but also with temporal data and information. Literature still provides limited documentation when it comes to user requirements for effective geo-collaborative work with spatio-temporal data. To start filling this gap, our study adopted a User-Centered Design approach and first explored the user requirements of environmental researchers working on distributed research projects for collaborative dissemination, exchange and work with spatio-temporal data. Our results show that system design will be mainly influenced by the nature and type of data users work with. From the end-users' perspective, optimal conversion of huge files of spatio-temporal data for further dissemination, accuracy of conversion, organization of content and security have a key role for effective geo-collaboration. Copyright © 2012 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  5. Relationship between impulsivity, hyperactivity and working memory: a differential analysis in the rat

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    Dellu-Hagedorn Françoise

    2006-03-01

    Full Text Available Abstract Background Impulsivity is a behavioural trait that comprises several distinct processes. It is a key feature of many psychopathologies such as mania, addictive disorders or attention deficit-hyperactivity disorders. To date, the aspects of impulsiveness involved in these pathologies have not yet been explicitly defined. In these disorders, sensation or drug seeking and cognitive deficits are closely related, but the nature of these relationships remains largely unknown. A new animal model of impulsiveness based on spontaneous inter-individual differences is proposed here to help clarify the relationship between characteristic aspects of impulsive-related pathologies. Methods Rats were divided into sub-groups according to their scores in three operant tasks with varying degrees of behavioural inhibition, timing and motor vs. cognitive impulsivity demands. These tasks included a fixed consecutive number schedule (ability to complete an action to receive a reinforcer, a multiple fixed-interval/extinction schedule of reinforcement (high level of responding, and a delayed reward task (delay discounting. In addition, measurements of locomotor responses to novelty and to amphetamine in a circular corridor, and working memory in an 8-arm radial maze were obtained. Results Substantial behavioural inter-individual differences were observed in each task, whereas few inter-task relationships were found. Impulsive rats, as defined in a task requiring inhibition of premature responses, presented a higher increase in amphetamine-induced locomotion. Reduced working memory performance was only observed in hyperactive rats in an extinction schedule. Conclusion This novel approach shows that distinct aspects of impulsiveness and hyperactivity can be expressed based on large inter-individual differences that vary from poorly to highly adapted behaviours ones in a normal population of rats. Inhibitory deficit was related to a higher response to

  6. Cinnamon users with prediabetes have a better fasting working memory: a cross-sectional function study.

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    Wahlqvist, Mark L; Lee, Meei-Shyuan; Lee, Jiunn-Tay; Hsu, Chih-Cheng; Chou, Yu-Ching; Fang, Wen-Hui; Liu, Hsiao-Yu; Xiu, Lili; Andrews, Zane B

    2016-04-01

    Working memory (WM) is impaired in prediabetes. We hypothesized that culinary herbs and spices may decrease insulin resistance (IR) and improve WM in prediabetes. Healthy people aged ≥60 years with prediabetes (fasting blood glucose 100-125 mg/dL) (47 men and 46 women) whose food and culinary herb intakes were established with a food frequency questionnaire had body composition assessed and fasting glucose and insulin measured. Working memory and Mini-Mental State Examination (MMSE) were assessed on the same occasion. The contributions to associations between WM and diet, body fat, and IR were estimated by linear regression. Compared with nonusers, cinnamon users had significantly less frequent physical activity (2.9 vs. 4.4 times per week) and more often used fresh ginger (93.3% vs. 64.1%) and ginger in cooking (60.0% vs. 32.1%). Cinnamon users also had a better WM (2.9 vs. 2.5, P < .001). Cinnamon had a significant effect (users were 0.446 higher), but not ginger or curry usage, in predicting WM. For sociodemographic variables, only education (years) was significant in predicting WM (β = 0.065). Other significant determinants of WM were total fat mass (kilograms) (β = -0.024) and MMSE (β = 0.075). After adjustment for age and sex, cinnamon use, education, and MMSE remained significant individual predictors. In the final model, in which all variables listed were adjusted simultaneously, cinnamon users still had a significantly higher WM than nonusers. Cinnamon usage is associated with a better WM, not accounted for by dietary quality or IR, in untreated prediabetes. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Psychotic Experiences and Working Memory: A Population-Based Study Using Signal-Detection Analysis.

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    Rodolfo Rossi

    Full Text Available Psychotic Experiences (PEs during adolescence index increased risk for psychotic disorders and schizophrenia in adult life. Working memory (WM deficits are a core feature of these disorders. Our objective was to examine the relationship between PEs and WM in a general population sample of young people in a case control study. 4744 individuals of age 17-18 from Bristol and surrounding areas (UK were analyzed in a cross-sectional study nested within the Avon Longitudinal Study of Parents and Children (ALSPAC birth cohort study. The dependent variable was PEs, assessed using the semi-structured Psychosis-Like Symptom Interview (PLIKSi. The independent variable was performance on a computerized numerical n-back working memory task. Signal-Detection Theory indices, including standardized hits rate, false alarms rate, discriminability index (d' and response bias (c from 2-Back and 3-Back tasks were calculated. 3576 and 3527 individuals had complete data for 2-Back and 3-Back respectively. Suspected/definite PEs prevalence was 7.9% (N = 374. Strongest evidence of association was seen between PEs and false alarms on the 2-Back, (odds ratio (OR = 1.17 [95% confidence intervals (CI 1.01, 1.35] and 3-back (OR = 1.35 [1.18, 1.54] and with c (OR = 1.59 [1.09, 2.34], and lower d' (OR = 0.76 [0.65, 0.89], on the 3-Back. Adjustment for several potential confounders, including general IQ, drug exposure and different psycho-social factors, and subsequent multiple imputation of missing data did not materially alter the results. WM is impaired in young people with PEs in the general population. False alarms, rather than poor accuracy, are more closely related to PEs. Such impairment is consistent with different neuropsychological models of psychosis focusing on signal-to-noise discrimination, probabilistic reasoning and impaired reality monitoring as a basis of psychotic symptoms.

  8. Mnemonic and attentional roles for states of attenuated alpha oscillations in perceptual working memory: a review.

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    van Ede, Freek

    2017-10-25

    Alpha oscillations are often reported to be amplified during working memory (WM) retention, serving to disengage sensory areas to protect internal representations from external interference. At the same time, contemporary views of WM postulate that sensory areas may often also be recruited for retention. I here review recent evidence that during such 'perceptual' WM, alpha oscillations in mnemonically relevant sensory areas are not amplified but attenuated instead. I will argue that such attenuated alpha states serve a mnemonic role and, further, that larger attenuation may support item-specific attentional prioritisation within perceptual WM. In critically evaluating this role, I also consider (and argue against) four alternatives to a strictly mnemonic account of the available data that may also prove useful to consider in future research. Finally, I highlight key implications of these data for the study of WM and for our understanding of the functional roles of states of attenuated alpha oscillations in cognition. © The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  9. Caffeine differentially alters cortical hemodynamic activity during working memory: a near infrared spectroscopy study.

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    Heilbronner, Urs; Hinrichs, Hermann; Heinze, Hans-Jochen; Zaehle, Tino

    2015-10-01

    Caffeine is a widely used stimulant with potentially beneficial effects on cognition as well as vasoconstrictive properties. In functional magnetic imaging research, caffeine has gained attention as a potential enhancer of the blood oxygenation level-dependent (BOLD) response. In order to clarify changes of oxy- and deoxyhemoglobin (HbO and HbR) induced by caffeine during a cognitive task, we investigated a working memory (WM) paradigm (visual 2-back) using near-infrared spectroscopy (NIRS). Behaviorally, caffeine had no effect on the WM performance but influenced reaction times in the 0-back condition. NIRS data demonstrate caffeine-dependent alterations of the course of the hemodynamic response. The intake of 200 mg caffeine caused a significant decrease of the HbO response between 20 and 40 s after the onset of a 2-back task in the bilateral inferior frontal cortex (IFC). In parallel, the HbR response of the left IFC was significantly increased due to caffeine intake. In line with previous results, we did not detect an effect of caffeine on most aspects of behavior. Effects of caffeine on brain vasculature were detected as general reduction of HbO. Neuronal effects of caffeine are reflected in an increased concentration of HbR in the left hemisphere when performing a verbal memory task and suggest influences on metabolism.

  10. The concentric model of human working memory: A validation study using complex span and updating tasks

    Directory of Open Access Journals (Sweden)

    Velichkovsky B. B.

    2017-09-01

    Full Text Available Background. Working memory (WM seems to be central to most forms of high-level cognition. This fact is fueling the growing interest in studying its structure and functional organization. The influential “concentric model” (Oberauer, 2002 suggests that WM contains a processing component and two storage components with different capacity limitations and sensitivity to interference. There is, to date, only limited support for the concentric model in the research literature, and it is limited to a number of specially designed tasks. Objective. In the present paper, we attempted to validate the concentric model by testing its major predictions using complex span and updating tasks in a number of experimental paradigms. Method. The model predictions were tested with the help of review of data obtained primarily in our own experiments in several research domains, including Sternberg’s additive factors method; factor structure of WM; serial position effects in WM; and WM performance in a sample with episodic long-term memory deficits. Results. Predictions generated by the concentric model were shown to hold in all these domains. In addition, several new properties of WM were identified. In particular, we recently found that WM indeed contains a processing component which functions independent of storage components. In turn, the latter were found to form a storage hierarchy which balances fast access to selected items, with the storing of large amounts of potentially relevant information. Processing and storage in WM were found to be dependent on shared cognitive resources which are dynamically allocated between WM components according to actual task requirements. e implications of these findings for the theory of WM are discussed. Conclusion. The concentric model was shown to be valid with respect to standard WM tasks. The concentric model others promising research perspectives for the study of higher- order cognition, including underlying

  11. Academic Outcomes 2 Years After Working Memory Training for Children With Low Working Memory: A Randomized Clinical Trial.

    Science.gov (United States)

    Roberts, Gehan; Quach, Jon; Spencer-Smith, Megan; Anderson, Peter J; Gathercole, Susan; Gold, Lisa; Sia, Kah-Ling; Mensah, Fiona; Rickards, Field; Ainley, John; Wake, Melissa

    2016-05-02

    Working memory training may help children with attention and learning difficulties, but robust evidence from population-level randomized controlled clinical trials is lacking. To test whether a computerized adaptive working memory intervention program improves long-term academic outcomes of children 6 to 7 years of age with low working memory compared with usual classroom teaching. Population-based randomized controlled clinical trial of first graders from 44 schools in Melbourne, Australia, who underwent a verbal and visuospatial working memory screening. Children were classified as having low working memory if their scores were below the 15th percentile on either the Backward Digit Recall or Mister X subtest from the Automated Working Memory Assessment, or if their scores were below the 25th percentile on both. These children were randomly assigned by an independent statistician to either an intervention or a control arm using a concealed computerized random number sequence. Researchers were blinded to group assignment at time of screening. We conducted our trial from March 1, 2012, to February 1, 2015; our final analysis was on October 30, 2015. We used intention-to-treat analyses. Cogmed working memory training, comprising 20 to 25 training sessions of 45 minutes' duration at school. Directly assessed (at 12 and 24 months) academic outcomes (reading, math, and spelling scores as primary outcomes) and working memory (also assessed at 6 months); parent-, teacher-, and child-reported behavioral and social-emotional functioning and quality of life; and intervention costs. Of 1723 children screened (mean [SD] age, 6.9 [0.4] years), 226 were randomized to each arm (452 total), with 90% retention at 1 year and 88% retention at 2 years; 90.3% of children in the intervention arm completed at least 20 sessions. Of the 4 short-term and working memory outcomes, 1 outcome (visuospatial short-term memory) benefited the children at 6 months (effect size, 0.43 [95% CI, 0

  12. Spatiotemporal oscillatory dynamics during the encoding and maintenance phases of a visual working memory task.

    Science.gov (United States)

    Heinrichs-Graham, Elizabeth; Wilson, Tony W

    2015-08-01

    Many electrophysiology studies have examined neural oscillatory activity during the encoding, maintenance, and/or retrieval phases of various working memory tasks. Together, these studies have helped illuminate the underlying neural dynamics, although much remains to be discovered and some findings have not replicated in subsequent work. In this study, we examined the oscillatory dynamics that serve visual working memory operations using high-density magnetoencephalography (MEG) and advanced time-frequency and beamforming methodology. Specifically, we recorded healthy adults while they performed a high-load, Sternberg-type working memory task, and focused on the encoding and maintenance phases. We found significant 9-16 Hz desynchronizations in the bilateral occipital cortices, left dorsolateral prefrontal cortex (DLPFC), and left superior temporal areas throughout the encoding phase. Our analysis of the dynamics showed that the left DLPFC and superior temporal desynchronization became stronger as a function of time during the encoding period, and was sustained throughout most of the maintenance phase until sharply decreasing in the milliseconds preceding retrieval. In contrast, desynchronization in occipital areas became weaker as a function of time during encoding and eventually evolved into a strong synchronization during the maintenance period, consistent with previous studies. These results provide clear evidence of dynamic network-level processes during the encoding and maintenance phases of working memory, and support the notion of a dynamic pattern of functionally-discrete subprocesses within each working memory phase. The presence of such dynamic oscillatory networks may be a potential source of inconsistent findings in this literature, as neural activity within these networks changes dramatically with time. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Activation and Binding in Verbal Working Memory: A Dual-Process Model for the Recognition of Nonwords

    Science.gov (United States)

    Oberauer, Klauss; Lange, Elke B.

    2009-01-01

    The article presents a mathematical model of short-term recognition based on dual-process models and the three-component theory of working memory [Oberauer, K. (2002). Access to information in working memory: Exploring the focus of attention. "Journal of Experimental Psychology: Learning, Memory, and Cognition, 28", 411-421]. Familiarity arises…

  14. Linking Working Memory and Long-Term Memory: A Computational Model of the Learning of New Words

    Science.gov (United States)

    Jones, Gary; Gobet, Fernand; Pine, Julian M.

    2007-01-01

    The nonword repetition (NWR) test has been shown to be a good predictor of children's vocabulary size. NWR performance has been explained using phonological working memory, which is seen as a critical component in the learning of new words. However, no detailed specification of the link between phonological working memory and long-term memory…

  15. Acute aerobic exercise increases cortical activity during working memory: a functional MRI study in female college students

    National Research Council Canada - National Science Library

    Li, Lin; Men, Wei-Wei; Chang, Yu-Kai; Fan, Ming-Xia; Ji, Liu; Wei, Gao-Xia

    2014-01-01

    .... However, neural correlates of its cognitive plasticity remain largely unknown. The present study examined the effect of a session of acute aerobic exercise on working memory task-evoked brain activity as well as task performance...

  16. Catechol-O-methyltransferase (COMT Genotype Affects Age-Related Changes in Plasticity in Working Memory: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Stephan Heinzel

    2014-01-01

    Full Text Available Objectives. Recent work suggests that a genetic variation associated with increased dopamine metabolism in the prefrontal cortex (catechol-O-methyltransferase Val158Met; COMT amplifies age-related changes in working memory performance. Research on younger adults indicates that the influence of dopamine-related genetic polymorphisms on working memory performance increases when testing the cognitive limits through training. To date, this has not been studied in older adults. Method. Here we investigate the effect of COMT genotype on plasticity in working memory in a sample of 14 younger (aged 24–30 years and 25 older (aged 60–75 years healthy adults. Participants underwent adaptive training in the n-back working memory task over 12 sessions under increasing difficulty conditions. Results. Both younger and older adults exhibited sizeable behavioral plasticity through training (P<.001, which was larger in younger as compared to older adults (P<.001. Age-related differences were qualified by an interaction with COMT genotype (P<.001, and this interaction was due to decreased behavioral plasticity in older adults carrying the Val/Val genotype, while there was no effect of genotype in younger adults. Discussion. Our findings indicate that age-related changes in plasticity in working memory are critically affected by genetic variation in prefrontal dopamine metabolism.

  17. Fluid/Spatial and Crystallized Intelligence in Relation to Domain-Specific Working Memory: A Latent-Variable Approach

    Science.gov (United States)

    Haavisto, Marja-Leena; Lehto, Juhani E.

    2005-01-01

    Fluid/spatial intelligence, crystallized intelligence and their relationships to verbal and visuospatial working memory (WM) were studied. A total of 120 Finnish Air Force recruits participated in this study. Fluid/spatial intelligence was assessed using four different tasks, while crystallized intelligence was defined with the help of test scores…

  18. An energy-efficient intrinsic functional organization of human working memory: A resting-state functional connectivity study.

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    Liu, Huaigui; Yu, Hongxu; Li, Yanjun; Qin, Wen; Xu, Lixue; Yu, Chunshui; Liang, Meng

    2017-01-01

    Working memory (WM) is the active maintenance of currently relevant information that was just experienced or retrieved from long-term memory but no longer exists in the external environment; however, the intrinsic functional organization of the brain underlying human WM performance remains largely unknown. We hypothesize that the intrinsic functional organization of human WM is an energy-efficient system. We tested this hypothesis by analyzing associations between WM performance (reaction times of correct responses) at different task difficulties (2-back and 3-back tasks) and the resting-state functional connectivity density (FCD) and strength (FCS) in 282 healthy young adults. Voxel-based FCD analysis showed that the reaction times were negatively correlated with the FCD values of several brain regions known to be engaged in WM performance: the right inferior parietal lobule and inferior frontal gyrus for both the 2-back and the 3-back tasks and the right superior parietal lobule, supramarginal gyrus, left inferior parietal lobule and bilateral middle occipital gyrus for the 3-back task. Further analyses showed that the FCS values of these regions with several frontal, parietal and occipital regions were also negatively correlated with the reaction times; the 3-back task was associated with much more functional connections than the 2-back task. These findings suggest that the intrinsic working memory network is an energy-efficient and hierarchical system. A simple working memory task is controlled only by the core subsystem; however, a complex working memory task is associated with more nodes and connections of the system. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. From distributed resources to limited slots in multiple-item working memory: a spiking network model with normalization.

    Science.gov (United States)

    Wei, Ziqiang; Wang, Xiao-Jing; Wang, Da-Hui

    2012-08-15

    Recent behavioral studies have given rise to two contrasting models for limited working memory capacity: a "discrete-slot" model in which memory items are stored in a limited number of slots, and a "shared-resource" model in which the neural representation of items is distributed across a limited pool of resources. To elucidate the underlying neural processes, we investigated a continuous network model for working memory of an analog feature. Our model network fundamentally operates with a shared resource mechanism, and stimuli in cue arrays are encoded by a distributed neural population. On the other hand, the network dynamics and performance are also consistent with the discrete-slot model, because multiple objects are maintained by distinct localized population persistent activity patterns (bump attractors). We identified two phenomena of recurrent circuit dynamics that give rise to limited working memory capacity. As the working memory load increases, a localized persistent activity bump may either fade out (so the memory of the corresponding item is lost) or merge with another nearby bump (hence the resolution of mnemonic representation for the merged items becomes blurred). We identified specific dependences of these two phenomena on the strength and tuning of recurrent synaptic excitation, as well as network normalization: the overall population activity is invariant to set size and delay duration; therefore, a constant neural resource is shared by and dynamically allocated to the memorized items. We demonstrate that the model reproduces salient observations predicted by both discrete-slot and shared-resource models, and propose testable predictions of the merging phenomenon.

  20. Acute aerobic exercise increases cortical activity during working memory: a functional MRI study in female college students.

    Science.gov (United States)

    Li, Lin; Men, Wei-Wei; Chang, Yu-Kai; Fan, Ming-Xia; Ji, Liu; Wei, Gao-Xia

    2014-01-01

    There is increasing evidence that acute aerobic exercise is associated with improved cognitive function. However, neural correlates of its cognitive plasticity remain largely unknown. The present study examined the effect of a session of acute aerobic exercise on working memory task-evoked brain activity as well as task performance. A within-subjects design with a counterbalanced order was employed. Fifteen young female participants (M = 19.56, SD = 0.81) were scanned using functional magnetic resonance imaging while performing a working memory task, the N-back task, both following an acute exercise session with 20 minutes of moderate intensity and a control rest session. Although an acute session of exercise did not improve behavioral performance, we observed that it had a significant impact on brain activity during the 2-back condition of the N-back task. Specifically, acute exercise induced increased brain activation in the right middle prefrontal gyrus, the right lingual gyrus, and the left fusiform gyrus as well as deactivations in the anterior cingulate cortexes, the left inferior frontal gyrus, and the right paracentral lobule. Despite the lack of an effect on behavioral measures, significant changes after acute exercise with activation of the prefrontal and occipital cortexes and deactivation of the anterior cingulate cortexes and left frontal hemisphere reflect the improvement of executive control processes, indicating that acute exercise could benefit working memory at a macro-neural level. In addition to its effects on reversing recent obesity and disease trends, our results provide substantial evidence highlighting the importance of promoting physical activity across the lifespan to prevent or reverse cognitive and neural decline.

  1. Propranolol reduces emotional distraction in working memory: a partial mediating role of propranolol-induced cortisol increases?

    Science.gov (United States)

    Oei, Nicole Y L; Tollenaar, Marieke S; Elzinga, Bernet M; Spinhoven, Philip

    2010-03-01

    Noradrenalin modulates prefrontal function, such as working memory (WM), and is associated with enhanced distractibility, and enhanced memory for emotional events and stimuli. The beta-blocker propranolol has been shown to reduce memory for emotional stimuli. Herein we describe investigations aimed at assessing whether the administration of propranolol would reduce the interference by emotional distractions during WM performance. In a between-subjects design, 48 young, healthy men received 80 mg propranolol (n=25) or placebo (n=23), before performing an "emotional Sternberg task" with neutral and negatively arousing distracters. Compared to placebo, propranolol impaired WM at low load, however, it also reduced the interference by emotional distracters at high load. Furthermore, an explorative moderated-mediation analysis indicated that the observed propranolol effects on emotional distraction were partially mediated by cortisol. In future non-clinical and clinical memory studies using propranolol administration, cortisol elevations should be monitored to further investigate the potential mediating role of cortisol. 2009 Elsevier Inc. All rights reserved.

  2. How high level of anxiety in Panic Disorder can interfere in working memory? A computer simulation and electrophysiological investigation.

    Science.gov (United States)

    Di Giorgio Silva, Luiza Wanick; Aprigio, Danielle; Di Giacomo, Jesse; Gongora, Mariana; Budde, Henning; Bittencourt, Juliana; Cagy, Mauricio; Teixeira, Silmar; Ribeiro, Pedro; de Carvalho, Marcele Regine; Freire, Rafael; Nardi, Antonio Egidio; Basile, Luis Fernando; Velasques, Bruna

    2017-12-01

    Panic disorder (PD) is characterized by repeated and unexpected attacks of intense anxiety, which are not restricted to a determined situation or circumstance. The coherence function has been used to investigate the communication among brain structures through the quantitative EEG (qEEG). The objective of this study is to analyze if there is a difference in frontoparietal gamma coherence (GC) between panic disorder patients (PDP) and healthy controls (HC) during the Visual oddball paradigm; and verify if high levels of anxiety (produced by a computer simulation) affect PDP's working memory. Nine PDP (9 female with average age of 48.8, SD: 11.16) and ten HC (1 male and 9 female with average age of 38.2, SD: 13.69) were enrolled in this study. The subjects performed the visual oddball paradigm simultaneously to the EEG record before and after the presentation of computer simulation (CS). A two-way ANOVA was applied to analyze the factors Group and the Moment for each pair of electrodes separately, and another one to analyze the reaction time variable. We verified a F3-P3 GC increased after the CS movie, demonstrating the left hemisphere participation during the anxiety processing. The greater GC in HC observed in the frontal and parietal areas (P3-Pz, F4-F8 and Fp2-F4) points to the participation of these areas with the expected behavior. The greater GC in PDP for F7-F3 and F4-P4 pairs of electrodes assumes that it produces a prejudicial "noise" during information processing, and can be associated to interference on the communication between frontal and parietal areas. This "noise" during information processing is related to PD symptoms, which should be better known in order to develop effective treatment strategies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Meta-analysis of the research impact of Baddeley's multicomponent working memory model and Cowan's embedded-processes model of working memory: A bibliometric mapping approach

    National Research Council Canada - National Science Library

    Aleksandra Gruszka; Jaroslaw Orzechowski

    2016-01-01

      In this study bibliometric mapping method was employed to visualise the current research trends and the impact of the two most influential models of working memory, namely: A. D. Baddeley and G. J. Hitch's (1974...

  4. Working memory load-dependent spatio-temporal activity of single-trial P3 response detected with an adaptive wavelet denoiser.

    Science.gov (United States)

    Zhang, Qiushi; Yang, Xueqian; Yao, Li; Zhao, Xiaojie

    2017-03-27

    Working memory (WM) refers to the holding and manipulation of information during cognitive tasks. Its underlying neural mechanisms have been explored through both functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). Trial-by-trial coupling of simultaneously collected EEG and fMRI signals has become an important and promising approach to study the spatio-temporal dynamics of such cognitive processes. Previous studies have demonstrated a modulation effect of the WM load on both the BOLD response in certain brain areas and the amplitude of P3. However, much remains to be explored regarding the WM load-dependent relationship between the amplitude of ERP components and cortical activities, and the low signal-to-noise ratio (SNR) of the EEG signal still poses a challenge to performing single-trial analyses. In this paper, we investigated the spatio-temporal activities of P3 during an n-back verbal WM task by introducing an adaptive wavelet denoiser into the extraction of single-trial P3 features and using general linear model (GLM) to integrate simultaneously collected EEG and fMRI data. Our results replicated the modulation effect of the WM load on the P3 amplitude. Additionally, the activation of single-trial P3 amplitudes was detected in multiple brain regions, including the insula, the cuneus, the lingual gyrus (LG), and the middle occipital gyrus (MOG). Moreover, we found significant correlations between P3 features and behavioral performance. These findings suggest that the single-trial integration of simultaneous EEG and fMRI signals may provide new insights into classical cognitive functions. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  5. Spatio-temporal elements of articulation work in the achievement of repeat prescribing safety in UK general practice.

    Science.gov (United States)

    Grant, Suzanne; Mesman, Jessica; Guthrie, Bruce

    2016-02-01

    Prescribing is the most common healthcare intervention, and is both beneficial and risky. An important source of risk in UK general practice is the management of 'repeat prescriptions', which are typically requested from and issued by non-clinically trained reception staff with only intermittent reauthorisation by a clinical prescriber. This paper ethnographically examines the formal and informal work employed by GPs and receptionists to safely conduct repeat prescribing work in primary care using Strauss's (1985, 1988, 1993) concept of 'articulation work' across eight UK general practices. The analytical lens of articulation work provided an investigative framing to contextually map the informal, invisible resources of resilience and strength employed by practice team members in the achievement of repeat prescribing safety, where risk and vulnerability were continually relocated across space and time. In particular, the paper makes visible the micro-level competencies and collaborative practices that were routinely employed by both GPs and receptionists across different socio-cultural contexts, with informal, cross-hierarchical communication usually considered more effective than the formal structures of communication that existed (e.g. protocols). While GPs held formal prescribing authority, this paper also examines the key role of receptionists in both the initiation and safe coordination of the repeat prescribing routine. © 2015 Foundation for the Sociology of Health & Illness.

  6. Granger causality analysis reveals distinct spatio-temporal connectivity patterns in motor and perceptual visuo-spatial working memory

    Directory of Open Access Journals (Sweden)

    Foteini eProtopapa

    2014-11-01

    Full Text Available We employed spectral Granger causality analysis on a full set of 56 electroencephalographic recordings acquired during the execution of either a 2D movement pointing or a perceptual (yes/no change detection task with memory and non memory conditions. On the basis of network characteristics across frequency bands, we provide evidence for the full dissociation of the corresponding cognitive processes. Movement-memory trial types exhibited higher degree nodes during the first 2 seconds of the delay period, mainly at central, left frontal and right-parietal areas. Change detection-memory trial types resulted in a three-peak temporal pattern of the total degree with higher degree nodes emerging mainly at central, right frontal and occipital areas. Functional connectivity networks resulting from non memory trial types were characterized by more sparse structures for both tasks. The movement-memory trial types encompassed an apparent coarse flow from frontal to parietal areas while the opposite flow from occipital, parietal to central and frontal areas was evident for the change detection-memory trial types. The differences among tasks and conditions were more profound in α (8-12 Hz and β (12-30 Hz and less in γ (30-45 Hz band. Our results favour the hypothesis which considers spatial working memory as a by-product of specific mental processes that engages common brain areas under different network organizations.

  7. Can the error detection mechanism benefit from training the working memory? A comparison between dyslexics and controls--an ERP study.

    Directory of Open Access Journals (Sweden)

    Tzipi Horowitz-Kraus

    Full Text Available BACKGROUND: Based on the relationship between working memory and error detection, we investigated the capacity of adult dyslexic readers' working memory to change as a result of training, and the impact of training on the error detection mechanism. METHODOLOGY: 27 dyslexics and 34 controls, all university students, participated in the study. ERP methodology and behavioral measures were employed prior to, immediately after, and 6 months after training. The CogniFit Personal Coach Program, which consists of 24 sessions of direct training of working memory skills, was used. FINDINGS: Both groups of readers gained from the training program but the dyslexic readers gained significantly more. In the dyslexic group, digit span increased from 9.84+/-3.15 to 10.79+/-3.03. Working memory training significantly increased the number of words per minute read correctly by 14.73%. Adult brain activity changed as a result of training, evidenced by an increase in both working memory capacity and the amplitude of the Error-related Negativity (ERN component (24.71%. When ERN amplitudes increased, the percentage of errors on the Sternberg tests decreased. CONCLUSIONS: We suggest that by expanding the working memory capacity, larger units of information are retained in the system, enabling more effective error detection. The crucial functioning of the central-executive as a sub-component of the working memory is also discussed.

  8. How music training enhances working memory: a cerebrocerebellar blending mechanism that can lead equally to scientific discovery and therapeutic efficacy in neurological disorders.

    Science.gov (United States)

    Vandervert, Larry

    2015-01-01

    Following in the vein of studies that concluded that music training resulted in plastic changes in Einstein's cerebral cortex, controlled research has shown that music training (1) enhances central executive attentional processes in working memory, and (2) has also been shown to be of significant therapeutic value in neurological disorders. Within this framework of music training-induced enhancement of central executive attentional processes, the purpose of this article is to argue that: (1) The foundational basis of the central executive begins in infancy as attentional control during the establishment of working memory, (2) In accordance with Akshoomoff, Courchesne and Townsend's and Leggio and Molinari's cerebellar sequence detection and prediction models, the rigors of volitional control demands of music training can enhance voluntary manipulation of information in thought and movement, (3) The music training-enhanced blending of cerebellar internal models in working memory as can be experienced as intuition in scientific discovery (as Einstein often indicated) or, equally, as moments of therapeutic advancement toward goals in the development of voluntary control in neurological disorders, and (4) The blending of internal models as in (3) thus provides a mechanism by which music training enhances central executive processes in working memory that can lead to scientific discovery and improved therapeutic outcomes in neurological disorders. Within the framework of Leggio and Molinari's cerebellar sequence detection model, it is determined that intuitive steps forward that occur in both scientific discovery and during therapy in those with neurological disorders operate according to the same mechanism of adaptive error-driven blending of cerebellar internal models. It is concluded that the entire framework of the central executive structure of working memory is a product of the cerebrocerebellar system which can, through the learning of internal models

  9. How music training enhances working memory: a cerebrocerebellar blending mechanism that can lead equally to scientific discovery and therapeutic efficacy in neurological disorders

    OpenAIRE

    Vandervert, Larry

    2015-01-01

    Background Following in the vein of studies that concluded that music training resulted in plastic changes in Einstein’s cerebral cortex, controlled research has shown that music training (1) enhances central executive attentional processes in working memory, and (2) has also been shown to be of significant therapeutic value in neurological disorders. Within this framework of music training-induced enhancement of central executive attentional processes, the purpose of this article is to argue...

  10. Meta-analysis of the research impact of Baddeley’s multicomponent working memory model and Cowan’s embedded-processes model of working memory: A bibliometric mapping approach

    National Research Council Canada - National Science Library

    Aleksandra Gruszka; Jarosław Orzechowski

    2016-01-01

    In this study bibliometric mapping method was employed to visualise the current research trends and the impact of the two most influential models of working memory, namely: A. D. Baddeley and G. J. Hitch’s (1974...

  11. Meta-analysis of the research impact of Baddeley’s multicomponent working memory model and Cowan’s embedded-processes model of working memory: A bibliometric mapping approach

    Directory of Open Access Journals (Sweden)

    Gruszka Aleksandra

    2016-04-01

    Full Text Available In this study bibliometric mapping method was employed to visualise the current research trends and the impact of the two most influential models of working memory, namely: A. D. Baddeley and G. J. Hitch’s (1974 multicomponent working memory model and N. Cowan’s (1988 embedded-processes model of working memory. Using VOSviewer software two maps were generated based on the index-term words extracted from the research papers citing Baddeley (2000 and Cowan (2001, respectively. The maps represent networks of co-occurrences of index terms and can be interpreted as an indication of the main research fields related to the examined models of WM. The results of the analysis revealed that the spheres of influence of the two main conceptualisations of WM are rather different than similar. Although the first two clusters, i.e. “brain mapping” and “higher-level cognition and development” are present in both maps, their relative importance varies. The remaining clusters are unique to each map. Baddeley’s theory seems to have a greater influence on “neuropsychology”, while Cowan’s theory - on basic research on “biological systems”, including the nervous system in humans and animals. The second difference between these theories concerns their relations to functions and dysfunctions associated with particular sensory modalities: in Baddelay’s theory with the “auditory modality” cluster, and in Cowan’s - with the “visual modality” one.

  12. Spatiotemporal Thinking in the Geosciences

    Science.gov (United States)

    Shipley, T. F.; Manduca, C. A.; Ormand, C. J.; Tikoff, B.

    2011-12-01

    Reasoning about spatial relations is a critical skill for geoscientists. Within the geosciences different disciplines may reason about different sorts of relationships. These relationships may span vastly different spatial and temporal scales (from the spatial alignment in atoms in crystals to the changes in the shape of plates). As part of work in a research center on spatial thinking in STEM education, we have been working to classify the spatial skills required in geology, develop tests for each spatial skill, and develop the cognitive science tools to promote the critical spatial reasoning skills. Research in psychology, neurology and linguistics supports a broad classification of spatial skills along two dimensions: one versus many objects (which roughly translates to object- focused and navigation focused skills) and static versus dynamic spatial relations. The talk will focus on the interaction of space and time in spatial cognition in the geosciences. We are working to develop measures of skill in visualizing spatiotemporal changes. A new test developed to measure visualization of brittle deformations will be presented. This is a skill that has not been clearly recognized in the cognitive science research domain and thus illustrates the value of interdisciplinary work that combines geosciences with cognitive sciences. Teaching spatiotemporal concepts can be challenging. Recent theoretical work suggests analogical reasoning can be a powerful tool to aid student learning to reason about temporal relations using spatial skills. Recent work in our lab has found that progressive alignment of spatial and temporal scales promotes accurate reasoning about temporal relations at geological time scales.

  13. Optimization of Spatiotemporal Apertures in Channel Sounding

    DEFF Research Database (Denmark)

    Pedersen, Troels; Pedersen, Claus; Yin, Xuefeng

    2008-01-01

    In this paper we investigate the impact of the spatio-temporal aperture of a channel sounding system equipped with antenna arrays at the transmitter and receiver on the accuracy of joint estimation of Doppler frequency and bi-direction. The contribution of this work is three-fold. Firstly, we state...

  14. Spatio-Temporal Rule Mining

    DEFF Research Database (Denmark)

    Gidofalvi, Gyozo; Pedersen, Torben Bach

    2005-01-01

    Recent advances in communication and information technology, such as the increasing accuracy of GPS technology and the miniaturization of wireless communication devices pave the road for Location-Based Services (LBS). To achieve high quality for such services, spatio-temporal data mining techniques...... are needed. In this paper, we describe experiences with spatio-temporal rule mining in a Danish data mining company. First, a number of real world spatio-temporal data sets are described, leading to a taxonomy of spatio-temporal data. Second, the paper describes a general methodology that transforms...... the spatio-temporal rule mining task to the traditional market basket analysis task and applies it to the described data sets, enabling traditional association rule mining methods to discover spatio-temporal rules for LBS. Finally, unique issues in spatio-temporal rule mining are identified and discussed....

  15. Climate-induced spatio-temporal changes of rock glacier kinematics and temperature regime of permafrost in the Hohe Tauern Range, Austria: One work package within the permAfrost project

    Science.gov (United States)

    Kellerer-Pirklbauer, A.; Avian, M.; Kaufmann, V.; Niesner, E.; Kühnast, B.

    2012-04-01

    High latitude as well as high mountain areas are recognized as being particularly sensitive to the effects of the ongoing climate change. Large areas of mountain permafrost in the European Alps are for instance close to melting conditions and are therefore very sensitive to minor changes in climatic conditions. Degrading permafrost might cause slope instabilities and therefore pose a threat to both infrastructure and humans in alpine and subalpine environments. However, knowledge regarding permafrost distribution and its climatologically driven dynamics in the European Alps is still far from being complete. To increase the knowledge about permafrost occurrence and dynamics in Austria and the Eastern European Alps, the national project "permAfrost - Austrian Permafrost Research Initiative" was launched in 2010. The project consortium consists of permafrost researcher from the University of Innsbruck, Graz University of Technology, University of Leoben, University of Salzburg, and Vienna University of Technology and is coordinated by the Austrian Academy of Sciences. permAfrost is a first step establishing a nation-wide permafrost monitoring program in Austria. One work package (WP) of permAfrost focuses on climate-induced spatio-temporal changes of rock glacier kinematics and temperature regime of permafrost at the three rock glaciers Weissenkar (N46°57´, E12°45´), Hinteres Langtalkar (N46°59´, E12°47´) and Dösen (N46°59´, E13°17´), all located in the Hohe Tauern Range, central Austria. This WP aims to continue and improve previous research in the field of kinematics, volumetric and thermal monitoring of rock glacier and permafrost and to understand the inner structure of the three mentioned rock glaciers. To reach this aim, a synergistic approach by using geodesy, aerial photogrammetry, terrestrial and airborne laser scanning, different geophysical techniques and automatic ground temperature and climate monitoring is applied. First results from the

  16. Spatiotemporal Modeling of Community Risk

    Science.gov (United States)

    2016-03-01

    fire personnel, this spatiotemporal anomaly is a well-known location for prostitution . Police RMS data may reveal similar trends to those seen by the...coincident spatiotemporal patterns. If there is any kind of causal connection, it is reasonable to assume that if the prostitution problem is addressed

  17. Visualization and assessment of spatio-temporal covariance properties

    KAUST Repository

    Huang, Huang

    2017-11-23

    Spatio-temporal covariances are important for describing the spatio-temporal variability of underlying random fields in geostatistical data. For second-order stationary random fields, there exist subclasses of covariance functions that assume a simpler spatio-temporal dependence structure with separability and full symmetry. However, it is challenging to visualize and assess separability and full symmetry from spatio-temporal observations. In this work, we propose a functional data analysis approach that constructs test functions using the cross-covariances from time series observed at each pair of spatial locations. These test functions of temporal lags summarize the properties of separability or symmetry for the given spatial pairs. We use functional boxplots to visualize the functional median and the variability of the test functions, where the extent of departure from zero at all temporal lags indicates the degree of non-separability or asymmetry. We also develop a rank-based nonparametric testing procedure for assessing the significance of the non-separability or asymmetry. Essentially, the proposed methods only require the analysis of temporal covariance functions. Thus, a major advantage over existing approaches is that there is no need to estimate any covariance matrix for selected spatio-temporal lags. The performances of the proposed methods are examined by simulations with various commonly used spatio-temporal covariance models. To illustrate our methods in practical applications, we apply it to real datasets, including weather station data and climate model outputs.

  18. Rainfall spatiotemporal variability relation to wetlands hydroperiods

    Science.gov (United States)

    Serrano-Hidalgo, Carmen; Guardiola-Albert, Carolina; Fernandez-Naranjo, Nuria

    2017-04-01

    Doñana natural space (Southwestern Spain) is one of the largest protected wetlands in Europe. The wide marshes present in this natural space have such ecological value that this wetland has been declared a Ramsar reserve in 1982. Apart from the extensive marsh, there are also small lagoons and seasonally flooded areas which are likewise essential to maintain a wide variety of valuable habitats. Hydroperiod, the length of time each point remains flooded along an annual cycle, is a critical ecological parameter that shapes aquatic plants and animals distribution and determines available habitat for many of the living organisms in the marshes. Recently, there have been published two different works estimating the hydroperiod of Doñana lagoons with Landsat Time Series images (Cifuentes et al., 2015; Díaz-Delgado et al., 2016). In both works the flooding cycle hydroperiod in Doñana marshes reveals a flooding regime mainly driven by rainfall, evapotranspiration, topography and local hydrological management actions. The correlation found between rainfall and hydroperiod is studied differently in both works. While in one the rainfall is taken from one raingauge (Cifuentes et al., 2015), the one performed by Díaz-Delgado (2016) uses annual rainfall maps interpolated with the inverse of the distance method. The rainfall spatiotemporal variability in this area can be highly significant; however the amount of this importance has not been quantified at the moment. In the present work the geostatistical tool known as spatiotemporal variogram is used to study the rainfall spatiotemporal variability. The spacetime package implemented in R (Pebesma, 2012) facilities its computation from a high rainfall data base of more than 100 raingauges from 1950 to 2016. With the aid of these variograms the rainfall spatiotemporal variability is quantified. The principal aim of the present work is the study of the relation between the rainfall spatiotemporal variability and the

  19. Spatiotemporal Data Organization and Application Research

    Science.gov (United States)

    Tan, C.; Yan, S.

    2017-09-01

    Organization and management of spatiotemporal data is a key support technology for intelligence in all fields of the smart city. The construction of a smart city cannot be realized without spatiotemporal data. Oriented to support intelligent applications this paper proposes an organizational model for spatiotemporal data, and details the construction of a spatiotemporal big data calculation, analysis, and service framework for highly efficient management and intelligent application of spatiotemporal data for the entire data life cycle.

  20. Expert memory: a comparison of four theories.

    Science.gov (United States)

    Gobet, F

    1998-05-01

    This paper compares four current theories of expertise with respect to chess players' memory: Chase and Simon's chunking theory, Holding's SEEK theory, Ericsson and Kintsch's long-term working memory theory, and Gobet and Simon's template theory (Chase, W.G., Simon, H.A., 1973a. Perception in chess. Cognitive Psychology 4, 55-81; Holding, D.H., 1985. The Psychology of Chess Skill. Erlbaum, Hillsdale, NJ; Ericsson, K.A., Kintsch, W., 1995. Long-term working memory. Psychological Review 102, 211-245; Gobet, F., Simon, H.A., 1996b. Templates in chess memory: a mechanism for recalling several boards. Cognitive Psychology 31, 1-40). The empirical areas showing the largest discriminative power include recall of random and distorted positions, recall with very short presentation times, and interference studies. Contrary to recurrent criticisms in the literature, it is shown that the chunking theory is consistent with most of the data. However, the best performance in accounting for the empirical evidence is obtained by the template theory. The theory, which unifies low-level aspects of cognition, such as chunks, with high-level aspects, such as schematic knowledge and planning, proposes that chunks are accessed through a discrimination net, where simple perceptual features are tested, and that they can evolve into more complex data structures (templates) specific to classes of positions. Implications for the study of expertise in general include the need for detailed process models of expert behavior and the need to use empirical data spanning the traditional boundaries of perception, memory, and problem solving.

  1. Vortioxetine dose-dependently reverses 5-HT depletion-induced deficits in spatial working and object recognition memory: a potential role for 5-HT1A receptor agonism and 5-HT3 receptor antagonism.

    Science.gov (United States)

    du Jardin, Kristian Gaarn; Jensen, Jesper Bornø; Sanchez, Connie; Pehrson, Alan L

    2014-01-01

    We previously reported that the investigational multimodal antidepressant, vortioxetine, reversed 5-HT depletion-induced memory deficits while escitalopram and duloxetine did not. The present report studied the effects of vortioxetine and the potential impact of its 5-HT1A receptor agonist and 5-HT3 receptor antagonist properties on 5-HT depletion-induced memory deficits. Recognition and spatial working memory were assessed in the object recognition (OR) and Y-maze spontaneous alternation (SA) tests, respectively. 5-HT depletion was induced in female Long-Evans rats using 4-cholro-DL-phenylalanine methyl ester HCl (PCPA) and receptor occupancies were determined by ex vivo autoradiography. Rats were acutely dosed with vortioxetine, ondansetron (5-HT3 receptor antagonist) or flesinoxan (5-HT1A receptor agonist). The effects of chronic vortioxetine administration on 5-HT depletion-induced memory deficits were also assessed. 5-HT depletion reliably impaired memory performance in both the tests. Vortioxetine reversed PCPA-induced memory deficits dose-dependently with a minimal effective dose (MED) ≤0.1mg/kg (∼80% 5-HT3 receptor occupancy; OR) and ≤3.0mg/kg (5-HT1A, 5-HT1B, 5-HT3 receptor occupancy: ∼15%, 60%, 95%) in SA. Ondansetron exhibited a MED ≤3.0μg/kg (∼25% 5-HT3 receptor occupancy; OR), but was inactive in the SA test. Flesinoxan had a MED ≤1.0mg/kg (∼25% 5-HT1A receptor occupancy; SA); only 1.0mg/kg ameliorated deficits in the NOR. Chronic p.o. vortioxetine administration significantly improved memory performance in OR and occupied 95%, 66%, and 9.5% of 5-HT3, 5-HT1B, and 5-HT1A receptors, respectively. Vortioxetine's effects on SA performance may involve 5-HT1A receptor agonism, but not 5-HT3 receptor antagonism, whereas the effects on OR performance may involve 5-HT3 receptor antagonism and 5-HT1A receptor agonism. Copyright © 2013 Elsevier B.V. and ECNP. All rights reserved.

  2. Spatiotemporal Data Mining: A Computational Perspective

    Directory of Open Access Journals (Sweden)

    Shashi Shekhar

    2015-10-01

    Full Text Available Explosive growth in geospatial and temporal data as well as the emergence of new technologies emphasize the need for automated discovery of spatiotemporal knowledge. Spatiotemporal data mining studies the process of discovering interesting and previously unknown, but potentially useful patterns from large spatiotemporal databases. It has broad application domains including ecology and environmental management, public safety, transportation, earth science, epidemiology, and climatology. The complexity of spatiotemporal data and intrinsic relationships limits the usefulness of conventional data science techniques for extracting spatiotemporal patterns. In this survey, we review recent computational techniques and tools in spatiotemporal data mining, focusing on several major pattern families: spatiotemporal outlier, spatiotemporal coupling and tele-coupling, spatiotemporal prediction, spatiotemporal partitioning and summarization, spatiotemporal hotspots, and change detection. Compared with other surveys in the literature, this paper emphasizes the statistical foundations of spatiotemporal data mining and provides comprehensive coverage of computational approaches for various pattern families. ISPRS Int. J. Geo-Inf. 2015, 4 2307 We also list popular software tools for spatiotemporal data analysis. The survey concludes with a look at future research needs.

  3. Spatio-temporal modeling of nonlinear distributed parameter systems

    CERN Document Server

    Li, Han-Xiong

    2011-01-01

    The purpose of this volume is to provide a brief review of the previous work on model reduction and identifi cation of distributed parameter systems (DPS), and develop new spatio-temporal models and their relevant identifi cation approaches. In this book, a systematic overview and classifi cation on the modeling of DPS is presented fi rst, which includes model reduction, parameter estimation and system identifi cation. Next, a class of block-oriented nonlinear systems in traditional lumped parameter systems (LPS) is extended to DPS, which results in the spatio-temporal Wiener and Hammerstein s

  4. INDEXING AND QUERY PROCESSING TECHNIQUES IN SPATIO-TEMPORAL DATA

    Directory of Open Access Journals (Sweden)

    A John

    2016-04-01

    Full Text Available Indexing and query processing is an emerging research field in spatio - temporal data. Most of the real-time applications such as location based services, fleet management, traffic prediction and radio frequency identification and sensor networks are based on spatiotemporal indexing and query processing. All the indexing and query processing applications is any one of the forms, such as spatio index access and supporting queries or spatio-temporal indexing method and support query or temporal dimension, while in spatial data it is considered as the second priority. In this paper, give the survey of the various uncertain indexing and query processing techniques. Most of the existing survey works on spatio-temporal are based on indexing methods and query processing, but presented separately. Both the indexing and querying are related, hence state - of - art of both the indexing and query processing techniques are considered together. This paper gives the details of spatio-temporal data classification, various types of indexing methods, query processing, application areas and research direction of spatio-temporal indexing and query processing.

  5. REVIEW ARTICLE: Spatio-temporal couplings in ultrashort laser pulses

    Science.gov (United States)

    Akturk, Selcuk; Gu, Xun; Bowlan, Pamela; Trebino, Rick

    2010-09-01

    The electric field of an ultrashort laser pulse often fails to separate into a product of purely temporal and purely spatial factors. These so-called spatio-temporal couplings constitute a broad range of physical effects, which often become important in applications. In this review, we compile some recent experimental and theoretical work on the understanding, avoidance and applications of these effects. We first present a discussion of the characteristics of pulses containing spatio-temporal couplings, including their sources, a mathematical description and the interdependence of different couplings. We then review different experimental methods for their characterization. Finally, we describe different applications of spatio-temporal couplings and suggest further schemes for their exploitation and avoidance.

  6. Spatiotemporal Wave Patterns: Information Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Mikhail Rabinovich; Lev Tsimring

    2006-01-20

    Pattern formation has traditionally been studied in non-equilibrium physics from the viewpoint of describing the basic structures and their interactions. While this is still an important area of research, the emphasis in the last few years has shifted towards analysis of specific properties of patterns in various complex media. For example, diverse and unexpected phenomena occur in neuro-like media that are characterized by highly non-trivial local dynamics. We carried out an active research program on analysis of spatio-temporal patterns in various physical systems (convection, oscillating fluid layer, soap film), as well as in neuro-like media, with an emphasis on informational aspects of the dynamics. Nonlinear nonequilibrium media and their discrete analogs have a unique ability to represent, memorize, and process the information contained in spatio-temporal patterns. Recent neurophysiological experiments demonstrated a certain universality of spatio-temporal representation of information by neural ensembles. Information processing is also revealed in the spatio-temporal dynamics of cellular patterns in nonequilibrium media. It is extremely important for many applications to study the informational aspects of these dynamics, including the origins and mechanisms of information generation, propagation and storage. Some of our results are: the discovery of self-organization of periodically oscillatory patterns in chaotic heterogeneous media; the analysis of the propagation of the information along a chaotic media as function of the entropy of the signal; the analysis of wave propagation in discrete non-equilibrium media with autocatalytic properties, which simulates the calcium dynamics in cellular membranes. Based on biological experiments we suggest the mechanism by which the spatial sensory information is transferred into the spatio-temporal code in the neural media. We also found a new mechanism of self-pinning in cellular structures and the related phenomenon

  7. Compact video synopsis via global spatiotemporal optimization.

    Science.gov (United States)

    Nie, Yongwei; Xiao, Chunxia; Sun, Hanqiu; Li, Ping

    2013-10-01

    Video synopsis aims at providing condensed representations of video data sets that can be easily captured from digital cameras nowadays, especially for daily surveillance videos. Previous work in video synopsis usually moves active objects along the time axis, which inevitably causes collisions among the moving objects if compressed much. In this paper, we propose a novel approach for compact video synopsis using a unified spatiotemporal optimization. Our approach globally shifts moving objects in both spatial and temporal domains, which shifting objects temporally to reduce the length of the video and shifting colliding objects spatially to avoid visible collision artifacts. Furthermore, using a multilevel patch relocation (MPR) method, the moving space of the original video is expanded into a compact background based on environmental content to fit with the shifted objects. The shifted objects are finally composited with the expanded moving space to obtain the high-quality video synopsis, which is more condensed while remaining free of collision artifacts. Our experimental results have shown that the compact video synopsis we produced can be browsed quickly, preserves relative spatiotemporal relationships, and avoids motion collisions.

  8. High Spatiotemporal Resolution Prostate MRI

    Science.gov (United States)

    2017-09-01

    AWARD NUMBER: W81XWH-15-1-0341 TITLE: High Spatiotemporal Resolution Prostate MRI PRINCIPAL INVESTIGATOR: Stephen J. Riederer, Ph.D...Resolution Prostate MRI 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-15-1-0341 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Stephen J. Riederer E-Mail...overall purpose of this project is to develop improved means using MRI for detecting prostate cancer with the potential for differentiating disease

  9. Spatio-Temporal Dynamics in Cellular Neural Networks

    Directory of Open Access Journals (Sweden)

    Liviu GORAS

    2009-07-01

    Full Text Available Analog Parallel Architectures like Cellular Neural Networks (CNN’s have been thoroughly studied not only for their potential in high-speed image processing applications but also for their rich and exciting spatio-temporal dynamics. An interesting behavior such architectures can exhibit is spatio-temporal filtering and pattern formation, aspects that will be discussed in this work for a general structure consisting of linear cells locally and homogeneously connected within a specified neighborhood. The results are generalizations of those regarding Turing pattern formation in CNN’s. Using linear cells (or piecewise linear cells working in the central linear part of their characteristic allows the use of the decoupling technique – a powerful technique that gives significant insight into the dynamics of the CNN. The roles of the cell structure as well as that of the connection template are discussed and models for the spatial modes dynamics are made as well.

  10. Probabilistic signatures of spatiotemporal intermittency in the ...

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... Keywords. Coupled map lattice; spatiotemporal intermittency; cellular automata. Abstract. The phase diagram of the coupled sine circle map system exhibits a variety of interesting phenomena including spreading regions with spatiotemporal intermittency, non-spreading regions with spatial intermittency, ...

  11. Visual Representations Of Non-Separable Spatiotemporal Covariance Models

    Science.gov (United States)

    Kolovos, A.; Christakos, G.; Hristopulos, D. T.; Serre, M. L.

    2003-12-01

    Natural processes that relate to climatic variability (such as air circulation, air-water and air-soil energy exchanges) contain inherently stochastic components. Spatiotemporal random fields are frequently employed to model such processes and deal with the uncertainty involved. Covariance functions are statistical tools that are used to express correlations between process values across space and time. This work focuses on a review and visual representation of a series of useful covariance models that have been introduced in the Modern Spatiotemporal Geostatistics literature. Some of their important features are examined and their application can significantly improve the interpretation of space/time correlations that affect the long-term climatic evolution both on a local or a global scale.

  12. Spatial and spatio-temporal bayesian models with R - INLA

    CERN Document Server

    Blangiardo, Marta

    2015-01-01

    Dedication iiiPreface ix1 Introduction 11.1 Why spatial and spatio-temporal statistics? 11.2 Why do we use Bayesian methods for modelling spatial and spatio-temporal structures? 21.3 Why INLA? 31.4 Datasets 32 Introduction to 212.1 The language 212.2 objects 222.3 Data and session management 342.4 Packages 352.5 Programming in 362.6 Basic statistical analysis with 393 Introduction to Bayesian Methods 533.1 Bayesian Philosophy 533.2 Basic Probability Elements 573.3 Bayes Theorem 623.4 Prior and Posterior Distributions 643.5 Working with the Posterior Distribution 663.6 Choosing the Prior Distr

  13. Mining sensor datasets with spatiotemporal neighborhoods

    Directory of Open Access Journals (Sweden)

    Michael Patrick McGuire

    2013-06-01

    Full Text Available Many spatiotemporal data mining methods are dependent on how relationships between a spatiotemporal unit and its neighbors are defined. These relationships are often termed the neighborhood of a spatiotemporal object. The focus of this paper is the discovery of spatiotemporal neighborhoods to find automatically spatiotemporal sub-regions in a sensor dataset. This research is motivated by the need to characterize large sensor datasets like those found in oceanographic and meteorological research. The approach presented in this paper finds spatiotemporal neighborhoods in sensor datasets by combining an agglomerative method to create temporal intervals and a graph-based method to find spatial neighborhoods within each temporal interval. These methods were tested on real-world datasets including (a sea surface temperature data from the Tropical Atmospheric Ocean Project (TAO array in the Equatorial Pacific Ocean and (b NEXRAD precipitation data from the Hydro-NEXRAD system. The results were evaluated based on known patterns of the phenomenon being measured. Furthermore, the results were quantified by performing hypothesis testing to establish the statistical significance using Monte Carlo simulations. The approach was also compared with existing approaches using validation metrics namely spatial autocorrelation and temporal interval dissimilarity. The results of these experiments show that our approach indeed identifies highly refined spatiotemporal neighborhoods.

  14. Spatiotemporal Frequent Pattern Discovery from Solar Event Metadata

    Science.gov (United States)

    Aydin, B.; Angryk, R.; Filali Boubrahimi, S.; Hamdi, S. M.

    2016-12-01

    Solar physics researchers entered the big data era with the launch of NASA's Solar Dynamics Observatory (SDO) mission, which captures approximately 60,000 high-resolution images every day and generates 0.55 petabytes of raster data each year. The big data trend in solar data is anticipated to be sustained by the ground-based DKIST telescope, which is expected to generate three to five petabytes of data each year. Many software modules continuously work on SDO's image data to detect spatial boundaries of solar events. Recently, a solar event tracking algorithm and interpolation methodologies have been proposed for creating large-scale solar event vector data sets in GSU's Data Mining Lab. The solar event tracking algorithm utilizes the spatial locations and corresponding image parameters for linking the polygon-based instances; therefore, creates spatiotemporal trajectory objects with extended geometric representations. Thus, we can access and make use of vector-based solar event metadata, which is in the form of continuously evolving region trajectories. Spatial and temporal patterns such as co-occurrences, sequences, periodicity and convergences frequently transpire among solar event instances. Here, we will concentrate on spatiotemporal co-occurrences and event sequences. Spatiotemporal co-occurrences are the spatial and temporal overlap among two or more solar event instances. On the other hand, spatiotemporal event sequences appear among the events that are temporally following each other and spatially in close-by locations. Our study includes approximately 120,000 trajectory-based instances of seven solar event types (Active Regions, Coronal Holes, Emerging Flux, Filaments, Flares, Sigmoids, and Sunspots) that occurred between January 2012 and December 2014. The tracked solar events are interpolated at each 10-minute interval. We will present the results of our spatiotemporal co-occurrence pattern mining and spatiotemporal event sequence mining algorithms

  15. Voila: Visual Anomaly Detection and Monitoring with Streaming Spatiotemporal Data.

    Science.gov (United States)

    Cao, Nan; Lin, Chaoguang; Zhu, Qiuhan; Lin, Yu-Ru; Teng, Xian; Wen, Xidao

    2018-01-01

    The increasing availability of spatiotemporal data continuously collected from various sources provides new opportunities for a timely understanding of the data in their spatial and temporal context. Finding abnormal patterns in such data poses significant challenges. Given that there is often no clear boundary between normal and abnormal patterns, existing solutions are limited in their capacity of identifying anomalies in large, dynamic and heterogeneous data, interpreting anomalies in their multifaceted, spatiotemporal context, and allowing users to provide feedback in the analysis loop. In this work, we introduce a unified visual interactive system and framework, Voila, for interactively detecting anomalies in spatiotemporal data collected from a streaming data source. The system is designed to meet two requirements in real-world applications, i.e., online monitoring and interactivity. We propose a novel tensor-based anomaly analysis algorithm with visualization and interaction design that dynamically produces contextualized, interpretable data summaries and allows for interactively ranking anomalous patterns based on user input. Using the "smart city" as an example scenario, we demonstrate the effectiveness of the proposed framework through quantitative evaluation and qualitative case studies.

  16. Spatiotemporal distribution modeling of PET tracer uptake in solid tumors.

    Science.gov (United States)

    Soltani, Madjid; Sefidgar, Mostafa; Bazmara, Hossein; Casey, Michael E; Subramaniam, Rathan M; Wahl, Richard L; Rahmim, Arman

    2017-02-01

    Distribution of PET tracer uptake is elaborately modeled via a general equation used for solute transport modeling. This model can be used to incorporate various transport parameters of a solid tumor such as hydraulic conductivity of the microvessel wall, transvascular permeability as well as interstitial space parameters. This is especially significant because tracer delivery and drug delivery to solid tumors are determined by similar underlying tumor transport phenomena, and quantifying the former can enable enhanced prediction of the latter. We focused on the commonly utilized FDG PET tracer. First, based on a mathematical model of angiogenesis, the capillary network of a solid tumor and normal tissues around it were generated. The coupling mathematical method, which simultaneously solves for blood flow in the capillary network as well as fluid flow in the interstitium, is used to calculate pressure and velocity distributions. Subsequently, a comprehensive spatiotemporal distribution model (SDM) is applied to accurately model distribution of PET tracer uptake, specifically FDG in this work, within solid tumors. The different transport mechanisms, namely convention and diffusion from vessel to tissue and in tissue, are elaborately calculated across the domain of interest and effect of each parameter on tracer distribution is investigated. The results show the convection terms to have negligible effect on tracer transport and the SDM can be solved after eliminating these terms. The proposed framework of spatiotemporal modeling for PET tracers can be utilized to comprehensively assess the impact of various parameters on the spatiotemporal distribution of PET tracers.

  17. Spatiotemporal control of cardiac alternans

    Science.gov (United States)

    Echebarria, Blas; Karma, Alain

    2002-09-01

    Electrical alternans are believed to be linked to the onset of life-threatening ventricular arrhythmias and sudden cardiac death. Recent studies have shown that alternans can be suppressed temporally by dynamic feedback control of the pacing interval. Here we investigate theoretically whether control can suppress alternans both temporally and spatially in homogeneous tissue paced at a single site. We first carry out ionic model simulations in a one-dimensional cable geometry which show that control is only effective up to a maximum cable length that decreases sharply away from the alternans bifurcation point. We then explain this finding by a linear stability analysis of an amplitude equation that describes the spatiotemporal evolution of alternans. This analysis reveals that control failure above a critical cable length is caused by the formation of standing wave patterns of alternans that are eigenfunctions of a forced Helmholtz equation, and therefore remarkably analogous to sound harmonics in an open pipe. We discuss the implications of these results for using control to suppress alternans in the human ventricles as well as to probe fundamental aspects of alternans morphogenesis.

  18. Modelling spatiotemporal change using multidimensional arrays Meng

    Science.gov (United States)

    Lu, Meng; Appel, Marius; Pebesma, Edzer

    2017-04-01

    The large variety of remote sensors, model simulations, and in-situ records provide great opportunities to model environmental change. The massive amount of high-dimensional data calls for methods to integrate data from various sources and to analyse spatiotemporal and thematic information jointly. An array is a collection of elements ordered and indexed in arbitrary dimensions, which naturally represent spatiotemporal phenomena that are identified by their geographic locations and recording time. In addition, array regridding (e.g., resampling, down-/up-scaling), dimension reduction, and spatiotemporal statistical algorithms are readily applicable to arrays. However, the role of arrays in big geoscientific data analysis has not been systematically studied: How can arrays discretise continuous spatiotemporal phenomena? How can arrays facilitate the extraction of multidimensional information? How can arrays provide a clean, scalable and reproducible change modelling process that is communicable between mathematicians, computer scientist, Earth system scientist and stakeholders? This study emphasises on detecting spatiotemporal change using satellite image time series. Current change detection methods using satellite image time series commonly analyse data in separate steps: 1) forming a vegetation index, 2) conducting time series analysis on each pixel, and 3) post-processing and mapping time series analysis results, which does not consider spatiotemporal correlations and ignores much of the spectral information. Multidimensional information can be better extracted by jointly considering spatial, spectral, and temporal information. To approach this goal, we use principal component analysis to extract multispectral information and spatial autoregressive models to account for spatial correlation in residual based time series structural change modelling. We also discuss the potential of multivariate non-parametric time series structural change methods, hierarchical

  19. Spatio-Temporal Analysis of Suicide-Related Emergency Calls

    Directory of Open Access Journals (Sweden)

    Miriam Marco

    2017-07-01

    Full Text Available Considerable effort has been devoted to incorporate temporal trends in disease mapping. In this line, this work describes the importance of including the effect of the seasonality in a particular setting related with suicides. In particular, the number of suicide-related emergency calls is modeled by means of an autoregressive approach to spatio-temporal disease mapping that allows for incorporating the possible interaction between both temporal and spatial effects. Results show the importance of including seasonality effect, as there are differences between the number of suicide-related emergency calls between the four seasons of each year.

  20. Mercury Toolset for Spatiotemporal Metadata

    Science.gov (United States)

    Wilson, Bruce E.; Palanisamy, Giri; Devarakonda, Ranjeet; Rhyne, B. Timothy; Lindsley, Chris; Green, James

    2010-01-01

    Mercury (http://mercury.ornl.gov) is a set of tools for federated harvesting, searching, and retrieving metadata, particularly spatiotemporal metadata. Version 3.0 of the Mercury toolset provides orders of magnitude improvements in search speed, support for additional metadata formats, integration with Google Maps for spatial queries, facetted type search, support for RSS (Really Simple Syndication) delivery of search results, and enhanced customization to meet the needs of the multiple projects that use Mercury. It provides a single portal to very quickly search for data and information contained in disparate data management systems, each of which may use different metadata formats. Mercury harvests metadata and key data from contributing project servers distributed around the world and builds a centralized index. The search interfaces then allow the users to perform a variety of fielded, spatial, and temporal searches across these metadata sources. This centralized repository of metadata with distributed data sources provides extremely fast search results to the user, while allowing data providers to advertise the availability of their data and maintain complete control and ownership of that data. Mercury periodically (typically daily) harvests metadata sources through a collection of interfaces and re-indexes these metadata to provide extremely rapid search capabilities, even over collections with tens of millions of metadata records. A number of both graphical and application interfaces have been constructed within Mercury, to enable both human users and other computer programs to perform queries. Mercury was also designed to support multiple different projects, so that the particular fields that can be queried and used with search filters are easy to configure for each different project.

  1. Spatiotemporal interactions in retinal prosthesis subjects.

    Science.gov (United States)

    Horsager, Alan; Greenberg, Robert J; Fine, Ione

    2010-02-01

    Vision loss due to retinitis pigmentosa affects an estimated 15 million people worldwide. Through collaboration between Second Sight Medical Products, Inc., and the Doheny Eye Institute, six blind human subjects underwent implantation with epiretinal 4 x 4 electrode arrays designed to directly stimulate the remaining cells of the retina, with the goal of restoring functional vision by applying spatiotemporal patterns of stimulation. To better understand spatiotemporal interactions between electrodes during synchronous and asynchronous stimulation, the authors investigated how percepts changed as a function of pulse timing across the electrodes. Pulse trains (20, 40, 80, and 160 Hz) were presented on groups of electrodes with 800, 1600, or 2400 microm center-to-center separation. Stimulation was either synchronous (pulses were presented simultaneously across electrodes) or asynchronous (pulses were phase shifted). Using a same-different discrimination task, the authors were able to evaluate how the perceptual quality of the stimuli changed as a function of phase shifts across multiple electrodes. Even after controlling for electric field interactions, subjects could discriminate between spatiotemporal pulse train patterns based on differences of phase across electrodes as small as 3 ms. These findings suggest that the quality of the percept is affected not only by electric field interactions but also by spatiotemporal interactions at the neural level. During multielectrode stimulation, interactions between electrodes have a significant influence on the quality of the percept. Understanding how these spatiotemporal interactions at the neural level influence percepts during multielectrode stimulation is fundamental to the successful design of a retinal prosthesis.

  2. spacetime : Spatio-Temporal Data in R

    Directory of Open Access Journals (Sweden)

    Edzer Pebesma

    2012-11-01

    Full Text Available This document describes classes and methods designed to deal with different types of spatio-temporal data in R implemented in the R package spacetime, and provides examples for analyzing them. It builds upon the classes and methods for spatial data from package sp, and for time series data from package xts. The goal is to cover a number of useful representations for spatio-temporal sensor data, and results from predicting (spatial and/or temporal interpolation or smoothing, aggregating, or subsetting them, and to represent trajectories. The goals of this paper is to explore how spatio-temporal data can be sensibly represented in classes, and to find out which analysis and visualisation methods are useful and feasible. We discuss the time series convention of representing time intervals by their starting time only. This document is the main reference for the R package spacetime, and is available (in updated form as a vignette in this package.

  3. Spatiotemporal canards in neural field equations

    Science.gov (United States)

    Avitabile, D.; Desroches, M.; Knobloch, E.

    2017-04-01

    Canards are special solutions to ordinary differential equations that follow invariant repelling slow manifolds for long time intervals. In realistic biophysical single-cell models, canards are responsible for several complex neural rhythms observed experimentally, but their existence and role in spatially extended systems is largely unexplored. We identify and describe a type of coherent structure in which a spatial pattern displays temporal canard behavior. Using interfacial dynamics and geometric singular perturbation theory, we classify spatiotemporal canards and give conditions for the existence of folded-saddle and folded-node canards. We find that spatiotemporal canards are robust to changes in the synaptic connectivity and firing rate. The theory correctly predicts the existence of spatiotemporal canards with octahedral symmetry in a neural field model posed on the unit sphere.

  4. Spatio-Temporal Data Exchange Standards

    DEFF Research Database (Denmark)

    Jensen, Christian Søndergaard; Schmidt, Albrecht

    2003-01-01

    We believe that research that concerns aspects of spatio-temporal data management may benefit from taking into account the various standards for spatio-temporal data formats. For example, this may contribute to rendering prototype software “open” and more readily useful. This paper thus identifies...... and briefly surveys standardization in relation to primarily the exchange and integration of spatio-temporal data. An overview of several data exchange languages is offered, along with reviews their potential for facilitating the collection of test data and the leveraging of prototypes. The standards, most...... of which are XML-based, lend themselves to the integration of prototypes into middleware architectures, e.g., as Web services....

  5. Hierarchic spatio-temporal dynamics in glycolysis

    Science.gov (United States)

    Shinjyo, Takahiro; Nakagawa, Yoshiyuki; Ueda, Tetsuo

    Yeast extracts exhibit oscillations when the glycolytic system is far away from equilibrium. Spatio-temporal dynamics in this system was studied in the newly developed gel as well as in the solution. Small regions (about 10 um) with very complex shape with high or low concentrations of NADH appeared, and upon these small structures large-scale dynamics were superimposed. Concentration waves propagated, and the source of wave was induced by contact with high ADP. Sink of waves was generated by contacting the reaction gel to two small gels rich in ADP. Upon these spatio-temporal dynamics were superimposed much slower global oscillations throughout the system with a period of about 40 min. Similar dynamics was seen in a solution of yeast extract, but the size of domains was about ten times larger than that in the gel. In this way, the multi-enzyme system of glycolysis exhibits self-organization of hierarchy in spatio-temporal dynamics.

  6. Spatiotemporal representation of cardiac vectorcardiogram (VCG signals

    Directory of Open Access Journals (Sweden)

    Yang Hui

    2012-03-01

    Full Text Available Abstract Background Vectorcardiogram (VCG signals monitor both spatial and temporal cardiac electrical activities along three orthogonal planes of the body. However, the absence of spatiotemporal resolution in conventional VCG representations is a major impediment for medical interpretation and clinical usage of VCG. This is especially so because time-domain features of 12-lead ECG, instead of both spatial and temporal characteristics of VCG, are widely used for the automatic assessment of cardiac pathological patterns. Materials and methods We present a novel representation approach that captures critical spatiotemporal heart dynamics by displaying the real time motion of VCG cardiac vectors in a 3D space. Such a dynamic display can also be realized with only one lead ECG signal (e.g., ambulatory ECG through an alternative lag-reconstructed ECG representation from nonlinear dynamics principles. Furthermore, the trajectories are color coded with additional dynamical properties of space-time VCG signals, e.g., the curvature, speed, octant and phase angles to enhance the information visibility. Results In this investigation, spatiotemporal VCG signal representation is used to characterize various spatiotemporal pathological patterns for healthy control (HC, myocardial infarction (MI, atrial fibrillation (AF and bundle branch block (BBB. The proposed color coding scheme revealed that the spatial locations of the peak of T waves are in the Octant 6 for the majority (i.e., 74 out of 80 of healthy recordings in the PhysioNet PTB database. In contrast, the peak of T waves from 31.79% (117/368 of MI subjects are found to remain in Octant 6 and the rest (68.21% spread over all other octants. The spatiotemporal VCG signal representation is shown to capture the same important heart characteristics as the 12-lead ECG plots and more. Conclusions Spatiotemporal VCG signal representation is shown to facilitate the characterization of space-time cardiac

  7. Data Flow Analysis and Visualization for Spatiotemporal Statistical Data without Trajectory Information.

    Science.gov (United States)

    Kim, Seokyeon; Jeong, Seongmin; Woo, Insoo; Jang, Yun; Maciejewski, Ross; Ebert, David S

    2018-03-01

    Geographic visualization research has focused on a variety of techniques to represent and explore spatiotemporal data. The goal of those techniques is to enable users to explore events and interactions over space and time in order to facilitate the discovery of patterns, anomalies and relationships within the data. However, it is difficult to extract and visualize data flow patterns over time for non-directional statistical data without trajectory information. In this work, we develop a novel flow analysis technique to extract, represent, and analyze flow maps of non-directional spatiotemporal data unaccompanied by trajectory information. We estimate a continuous distribution of these events over space and time, and extract flow fields for spatial and temporal changes utilizing a gravity model. Then, we visualize the spatiotemporal patterns in the data by employing flow visualization techniques. The user is presented with temporal trends of geo-referenced discrete events on a map. As such, overall spatiotemporal data flow patterns help users analyze geo-referenced temporal events, such as disease outbreaks, crime patterns, etc. To validate our model, we discard the trajectory information in an origin-destination dataset and apply our technique to the data and compare the derived trajectories and the original. Finally, we present spatiotemporal trend analysis for statistical datasets including twitter data, maritime search and rescue events, and syndromic surveillance.

  8. Coding of spatio-temporal attributes: the roles of age and enriched ...

    African Journals Online (AJOL)

    ... the study for assessment of spatio-temporal working memory in preclinical trials. Twenty six naive male long evan rats between the ages of 9-21 months, weighing between 200-400g were use for the study. They were divided into 3 groups: enriched young adults, non-enriched young adults and non-enriched older adults.

  9. Large scale stochastic spatio-temporal modelling with PCRaster

    Science.gov (United States)

    Karssenberg, Derek; Drost, Niels; Schmitz, Oliver; de Jong, Kor; Bierkens, Marc F. P.

    2013-04-01

    PCRaster is a software framework for building spatio-temporal models of land surface processes (http://www.pcraster.eu). Building blocks of models are spatial operations on raster maps, including a large suite of operations for water and sediment routing. These operations are available to model builders as Python functions. The software comes with Python framework classes providing control flow for spatio-temporal modelling, Monte Carlo simulation, and data assimilation (Ensemble Kalman Filter and Particle Filter). Models are built by combining the spatial operations in these framework classes. This approach enables modellers without specialist programming experience to construct large, rather complicated models, as many technical details of modelling (e.g., data storage, solving spatial operations, data assimilation algorithms) are taken care of by the PCRaster toolbox. Exploratory modelling is supported by routines for prompt, interactive visualisation of stochastic spatio-temporal data generated by the models. The high computational requirements for stochastic spatio-temporal modelling, and an increasing demand to run models over large areas at high resolution, e.g. in global hydrological modelling, require an optimal use of available, heterogeneous computing resources by the modelling framework. Current work in the context of the eWaterCycle project is on a parallel implementation of the modelling engine, capable of running on a high-performance computing infrastructure such as clusters and supercomputers. Model runs will be distributed over multiple compute nodes and multiple processors (GPUs and CPUs). Parallelization will be done by parallel execution of Monte Carlo realizations and sub regions of the modelling domain. In our approach we use multiple levels of parallelism, improving scalability considerably. On the node level we will use OpenCL, the industry standard for low-level high performance computing kernels. To combine multiple nodes we will use

  10. Modeling Topological Relationships between Fuzzy Spatio-Temporal Objects

    Directory of Open Access Journals (Sweden)

    Haitao Cheng

    2016-12-01

    Full Text Available Topological relationships between spatio-temporal objects are the most fundamental elements in spatio-temporal database systems, GIS, and image database systems. The research issue of modeling topological relationships has increasingly attracted attention, especially for querying of spatio-temporal objects and reasoning of topological relationships. Currently, topological relationship operating on spatio-temporal objects with precisely defined boundaries has been well studied. However, in the real world, spatio-temporal objects are not always crisp but with the nature of fuzziness and imprecision. Therefore, how to model topological relationship between fuzzy spatio-temporal objects is a significant topic and needs more investigations. This paper presents a study on modeling topological relationships between fuzzy spatio-temporal objects. Firstly, we give a model of fuzzy spatio-temporal objects in three-dimensional space and define those objects as moving fuzzy points, moving fuzzy lines, and moving fuzzy regions. On this basis, we propose a model for identifying basic topological relations between fuzzy spatio-temporal objects. Furthermore, in order to describe the evolution of basic topological relations over time, we give a model of complex topological relationships which are the sequences of basic relationships. The benefit of this model is that the complex topological relationships can be used as fuzzy spatio-temporal query operators in query languages. Finally, we provide some query examples to demonstrate fuzzy spatio-temporal queries in spatio-temporal database.

  11. Spatio-temporal change detection from multidimensional arrays

    NARCIS (Netherlands)

    Lu, Meng; Pebesma, Edzer; Sanchez, Alber; Verbesselt, Jan

    2016-01-01

    Growing availability of long-term satellite imagery enables change modeling with advanced spatio-temporal statistical methods. Multidimensional arrays naturally match the structure of spatio-temporal satellite data and can provide a clean modeling process for complex spatio-temporal analysis over

  12. Probabilistic signatures of spatiotemporal intermittency in the ...

    Indian Academy of Sciences (India)

    Coupled map lattice; spatiotemporal intermittency; cellular automata. PACS Nos 05.45.Ra; 05.45.-a; 05.45.Df; 64.60.Ak. 1. Introduction. The coupled sine circle map lattice has been known to model the mode-locking behaviour [1] seen commonly in coupled oscillators, Josephson junction arrays, etc., and is also found to be ...

  13. The Spatiotemporal Dynamics of Digital News Audiences

    DEFF Research Database (Denmark)

    Peters, Chris

    2016-01-01

    these interrelated changes in the media ecology if we want to grasp the newfound complexity of media consumption. Specifically, it outlines how audience engagement with news and different spatiotemporal configurations made possible by digital technology are trends that complement and reinforce one another in terms...

  14. Spatio-Temporal Saliency for Action Similarity

    NARCIS (Netherlands)

    Burghouts, G.J.; Broek, S.P. van den; Hove, R.J.M. ten

    2013-01-01

    Human actions are spatio-temporal patterns. A popular representation is to describe the action by features at interest points. Because the interest point detection and feature description are generic processes, they are not tuned to discriminate one particular action from the other. In this paper we

  15. Analyzing Spatiotemporal Anomalies through Interactive Visualization

    Directory of Open Access Journals (Sweden)

    Tao Zhang

    2014-06-01

    Full Text Available As we move into the big data era, data grows not just in size, but also in complexity, containing a rich set of attributes, including location and time information, such as data from mobile devices (e.g., smart phones, natural disasters (e.g., earthquake and hurricane, epidemic spread, etc. We are motivated by the rising challenge and build a visualization tool for exploring generic spatiotemporal data, i.e., records containing time location information and numeric attribute values. Since the values often evolve over time and across geographic regions, we are particularly interested in detecting and analyzing the anomalous changes over time/space. Our analytic tool is based on geographic information system and is combined with spatiotemporal data mining algorithms, as well as various data visualization techniques, such as anomaly grids and anomaly bars superimposed on the map. We study how effective the tool may guide users to find potential anomalies through demonstrating and evaluating over publicly available spatiotemporal datasets. The tool for spatiotemporal anomaly analysis and visualization is useful in many domains, such as security investigation and monitoring, situation awareness, etc.

  16. Comparison of Spatiotemporal Fusion Models: A Review

    Directory of Open Access Journals (Sweden)

    Bin Chen

    2015-02-01

    Full Text Available Simultaneously capturing spatial and temporal dynamics is always a challenge for the remote sensing community. Spatiotemporal fusion has gained wide interest in various applications for its superiority in integrating both fine spatial resolution and frequent temporal coverage. Though many advances have been made in spatiotemporal fusion model development and applications in the past decade, a unified comparison among existing fusion models is still limited. In this research, we classify the models into three categories: transformation-based, reconstruction-based, and learning-based models. The objective of this study is to (i compare four fusion models (STARFM, ESTARFM, ISTAFM, and SPSTFM under a one Landsat-MODIS (L-M pair prediction mode and two L-M pair prediction mode using time-series datasets from the Coleambally irrigation area and Poyang Lake wetland; (ii quantitatively assess prediction accuracy considering spatiotemporal comparability, landscape heterogeneity, and model parameter selection; and (iii discuss the advantages and disadvantages of the three categories of spatiotemporal fusion models.

  17. Spatiotemporal distribution and impact of diamondback moth ...

    African Journals Online (AJOL)

    Spatiotemporal distribution and impact of diamondback moth parasitoids in the Dakar Niayes in Senegal. Babacar ... Conservation biological control, which fosters the optimal use of indigenous natural enemies, is a promising way for reducing pesticide .... R Core, Package 'Facto Mine R'). The rate of parasitism is calculated ...

  18. SPATIO-TEMPORAL CLUSTER ANALYSIS OF DISEASE

    Directory of Open Access Journals (Sweden)

    M. S. Abramovich

    2014-01-01

    Full Text Available The robust version of the spatial scanning statistics for clustering is proposed. Spatio-temporal cluster analysis algorithms were used for the cluster detection of incidence of thyroid carcinoma. Me-thods and algorithms of detection and building clusters for disease on studying territories are consi-dered.

  19. Spatiotemporal solitons in quadratic nonlinear media

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 57; Issue 5-6. Spatiotemporal solitons in ... Department of Applied Physics, 212 Clark Hall, Cornell University, Ithaca, New York 14853, USA ... Proceedings of the International Workshop/Conference on Computational Condensed Matter Physics and Materials Science

  20. Chaotic Synchronization of Fractional-Order Spatiotemporal Coupled Lorenz System

    Science.gov (United States)

    Wang, Xing-Yuan; Zhang, Hao

    2012-10-01

    By utilizing the fractional calculus techniques and spatiotemporal chaos theory, this paper brings Lorenz system to fractional-order spatiotemporal coupled differential equation for the first time, and proposes the fractional-order spatiotemporal coupled Lorenz system. Based on that, we study the problem of chaotic synchronization of fractional-order spatiotemporal coupled Lorenz systems, design the linear controller and nonlinear controller by utilizing the Lyapunov stability theory and prove the correctness in theory. The numerical simulation results demonstrate the validity of controllers in high-dimension fractional-order spatiotemporal coupled Lorenz system.

  1. Relaxation Dynamics of Spatiotemporal Chaos in the Nematic Liquid Crystal

    Science.gov (United States)

    Nugroho, Fahrudin; Ueki, Tatsuhiro; Hidaka, Yoshiki; Kai, Shoichi

    2011-11-01

    We are working on the electroconvection of nematic liquid crystals, in which a kind of spatiotemporal chaos called as a soft-mode turbulence (SMT) is observed. The SMT is caused by the nonlinear interaction between the convective modes and the Nambu--Goldstone (NG) modes. By applying an external magnetic field H, the NG mode is suppressed and an ordered pattern can be observed. By removing the suppression effect the ordered state relax to its original SMT pattern. We revealed two types of instability govern the relaxation process: the zigzag instability and the free rotation of wavevector q(r). This work is partially supported by Grant-in-Aid for Scientific Research (Nos. 20111003, 21340110, and 21540391) from the Ministry of Education, Culture, Sport, Science, and Technology of Japan and the Japan Society for the Promotion of Science (JSPS).

  2. Termites promote resistance of decomposition to spatiotemporal variability in rainfall.

    Science.gov (United States)

    Veldhuis, Michiel P; Laso, Francisco J; Olff, Han; Berg, Matty P

    2017-02-01

    The ecological impact of rapid environmental change will depend on the resistance of key ecosystems processes, which may be promoted by species that exert strong control over local environmental conditions. Recent theoretical work suggests that macrodetritivores increase the resistance of African savanna ecosystems to changing climatic conditions, but experimental evidence is lacking. We examined the effect of large fungus-growing termites and other non-fungus-growing macrodetritivores on decomposition rates empirically with strong spatiotemporal variability in rainfall and temperature. Non-fungus-growing larger macrodetritivores (earthworms, woodlice, millipedes) promoted decomposition rates relative to microbes and small soil fauna (+34%) but both groups reduced their activities with decreasing rainfall. However, fungus-growing termites increased decomposition rates strongest (+123%) under the most water-limited conditions, making overall decomposition rates mostly independent from rainfall. We conclude that fungus-growing termites are of special importance in decoupling decomposition rates from spatiotemporal variability in rainfall due to the buffered environment they create within their extended phenotype (mounds), that allows decomposition to continue when abiotic conditions outside are less favorable. This points at a wider class of possibly important ecological processes, where soil-plant-animal interactions decouple ecosystem processes from large-scale climatic gradients. This may strongly alter predictions from current climate change models. © 2016 by the Ecological Society of America.

  3. Insight provenance for spatiotemporal visual analytics: Theory, review, and guidelines

    Directory of Open Access Journals (Sweden)

    Andreas Hall

    2017-12-01

    Full Text Available Research on provenance, which focuses on different ways to describe and record the history of changes and advances made throughout an analysis process, is an integral part of visual analytics. This paper focuses on providing the provenance of insight and rationale through visualizations while emphasizing, first, that this entails a profound understanding of human cognition and reasoning and that, second, the special nature of spatiotemporal data needs to be acknowledged in this process. A recently proposed human reasoning framework for spatiotemporal analysis, and four guidelines for the creation of visualizations that provide the provenance of insight and rationale published in relation to that framework, work as a starting point for this paper. While these guidelines are quite abstract, this paper set out to create a set of more concrete guidelines. On the basis of a review of available provenance solutions, this paper identifies a set of key features that are of relevance when providing the provenance of insight and rationale and, on the basis of these features, produces a new set of complementary guidelines that are more practically oriented than the original ones. Together, these two sets of guidelines provide both a theoretical and practical approach to the problem of providing the provenance of insight and rationale. Providing these kinds of guidelines represents a new approach in provenance research.

  4. Placing invasive species management in a spatiotemporal context.

    Science.gov (United States)

    Baker, Christopher M; Bode, Michael

    2016-04-01

    Invasive species are a worldwide issue, both ecologically and economically. A large body of work focuses on various aspects of invasive species control, including how to allocate control efforts to eradicate an invasive population as cost effectively as possible: There are a diverse range of invasive species management problems, and past mathematical analyses generally focus on isolated examples, making it hard to identify and understand parallels between the different contexts. In this study, we use a single spatiotemporal model to tackle the problem of allocating control effort for invasive species when suppressing an island invasive species, and for long-term spatial suppression projects. Using feral cat suppression as an illustrative example, we identify the optimal resource allocation for island and mainland suppression projects. Our results demonstrate how using a single model to solve different problems reveals similar characteristics of the solutions in different scenarios. As well as illustrating the insights offered by linking problems through a spatiotemporal model, we also derive novel and practically applicable results for our case studies. For temporal suppression projects on islands, we find that lengthy projects are more cost effective and that rapid control projects are only economically cost effective when population growth rates are high or diminishing returns on control effort are low. When suppressing invasive species around conservation assets (e.g., national parks or exclusion fences), we find that the size of buffer zones should depend on the ratio of the species growth and spread rate.

  5. SCREEN MEMORIES: A NEGLECTED FREUDIAN DISCOVERY?

    Science.gov (United States)

    Mahon, Eugene J

    2016-01-01

    In 1899, Freud introduced the concept of screen memories. His insights were revolutionary: screen memories do not emerge into consciousness at the time of recall, he argued; they are formed at that time and, moreover, historical accuracy is not their prime concern. In this article, the author reviews two of Freud's screen memories, as well as two screen memories from a completed analysis of one of his own patients. He argues that, if screen memories are formed, a concept such as screen work must be invoked as the agent of their formation. While screen memories may theoretically be formed at any stage of life, adolescence may be a prime time for their formation. © 2016 The Psychoanalytic Quarterly, Inc.

  6. Energy prediction using spatiotemporal pattern networks

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Zhanhong; Liu, Chao; Akintayo, Adedotun; Henze, Gregor P.; Sarkar, Soumik

    2017-11-01

    This paper presents a novel data-driven technique based on the spatiotemporal pattern network (STPN) for energy/power prediction for complex dynamical systems. Built on symbolic dynamical filtering, the STPN framework is used to capture not only the individual system characteristics but also the pair-wise causal dependencies among different sub-systems. To quantify causal dependencies, a mutual information based metric is presented and an energy prediction approach is subsequently proposed based on the STPN framework. To validate the proposed scheme, two case studies are presented, one involving wind turbine power prediction (supply side energy) using the Western Wind Integration data set generated by the National Renewable Energy Laboratory (NREL) for identifying spatiotemporal characteristics, and the other, residential electric energy disaggregation (demand side energy) using the Building America 2010 data set from NREL for exploring temporal features. In the energy disaggregation context, convex programming techniques beyond the STPN framework are developed and applied to achieve improved disaggregation performance.

  7. Statistical methods for spatio-temporal systems

    CERN Document Server

    Finkenstadt, Barbel

    2006-01-01

    Statistical Methods for Spatio-Temporal Systems presents current statistical research issues on spatio-temporal data modeling and will promote advances in research and a greater understanding between the mechanistic and the statistical modeling communities.Contributed by leading researchers in the field, each self-contained chapter starts with an introduction of the topic and progresses to recent research results. Presenting specific examples of epidemic data of bovine tuberculosis, gastroenteric disease, and the U.K. foot-and-mouth outbreak, the first chapter uses stochastic models, such as point process models, to provide the probabilistic backbone that facilitates statistical inference from data. The next chapter discusses the critical issue of modeling random growth objects in diverse biological systems, such as bacteria colonies, tumors, and plant populations. The subsequent chapter examines data transformation tools using examples from ecology and air quality data, followed by a chapter on space-time co...

  8. What Is Spatio-Temporal Data Warehousing?

    Science.gov (United States)

    Vaisman, Alejandro; Zimányi, Esteban

    In the last years, extending OLAP (On-Line Analytical Processing) systems with spatial and temporal features has attracted the attention of the GIS (Geographic Information Systems) and database communities. However, there is no a commonly agreed definition of what is a spatio-temporal data warehouse and what functionality such a data warehouse should support. Further, the solutions proposed in the literature vary considerably in the kind of data that can be represented as well as the kind of queries that can be expressed. In this paper we present a conceptual framework for defining spatio-temporal data warehouses using an extensible data type system. We also define a taxonomy of different classes of queries of increasing expressive power, and show how to express such queries using an extension of the tuple relational calculus with aggregated functions.

  9. Spatio-Temporal Modeling of Neuron Fields

    DEFF Research Database (Denmark)

    Lund, Adam

    The starting point and focal point for this thesis was stochastic dynamical modelling of neuronal imaging data with the declared objective of drawing inference, within this model framework, in a large-scale (high-dimensional) data setting. Implicitly this objective entails carrying out three......-temporal array data. This framework was developed with neuron field models in mind but may in turn be applied to other settings conforming to the spatio-temporal array data setup....

  10. Spatiotemporal patterns and predictability of cyberattacks.

    Directory of Open Access Journals (Sweden)

    Yu-Zhong Chen

    Full Text Available A relatively unexplored issue in cybersecurity science and engineering is whether there exist intrinsic patterns of cyberattacks. Conventional wisdom favors absence of such patterns due to the overwhelming complexity of the modern cyberspace. Surprisingly, through a detailed analysis of an extensive data set that records the time-dependent frequencies of attacks over a relatively wide range of consecutive IP addresses, we successfully uncover intrinsic spatiotemporal patterns underlying cyberattacks, where the term "spatio" refers to the IP address space. In particular, we focus on analyzing macroscopic properties of the attack traffic flows and identify two main patterns with distinct spatiotemporal characteristics: deterministic and stochastic. Strikingly, there are very few sets of major attackers committing almost all the attacks, since their attack "fingerprints" and target selection scheme can be unequivocally identified according to the very limited number of unique spatiotemporal characteristics, each of which only exists on a consecutive IP region and differs significantly from the others. We utilize a number of quantitative measures, including the flux-fluctuation law, the Markov state transition probability matrix, and predictability measures, to characterize the attack patterns in a comprehensive manner. A general finding is that the attack patterns possess high degrees of predictability, potentially paving the way to anticipating and, consequently, mitigating or even preventing large-scale cyberattacks using macroscopic approaches.

  11. Spatio-temporal Analysis for New York State SPARCS Data.

    Science.gov (United States)

    Chen, Xin; Wang, Yu; Schoenfeld, Elinor; Saltz, Mary; Saltz, Joel; Wang, Fusheng

    2017-01-01

    Increased accessibility of health data provides unique opportunities to discover spatio-temporal patterns of diseases. For example, New York State SPARCS (Statewide Planning and Research Cooperative System) data collects patient level detail on patient demographics, diagnoses, services, and charges for each hospital inpatient stay and outpatient visit. Such data also provides home addresses for each patient. This paper presents our preliminary work on spatial, temporal, and spatial-temporal analysis of disease patterns for New York State using SPARCS data. We analyzed spatial distribution patterns of typical diseases at ZIP code level. We performed temporal analysis of common diseases based on 12 years' historical data. We then compared the spatial variations for diseases with different levels of clustering tendency, and studied the evolution history of such spatial patterns. Case studies based on asthma demonstrated that the discovered spatial clusters are consistent with prior studies. We visualized our spatial-temporal patterns as animations through videos.

  12. Spatio-temporal flow maps for visualizing movement and contact patterns

    Directory of Open Access Journals (Sweden)

    Bing Ni

    2017-03-01

    Full Text Available The advanced telecom technologies and massive volumes of intelligent mobile phone users have yielded a huge amount of real-time data of people’s all-in-one telecommunication records, which we call telco big data. With telco data and the domain knowledge of an urban city, we are now able to analyze the movement and contact patterns of humans in an unprecedented scale. Flow map is widely used to display the movements of humans from one single source to multiple destinations by representing locations as nodes and movements as edges. However, it fails the task of visualizing both movement and contact data. In addition, analysts often need to compare and examine the patterns side by side, and do various quantitative analysis. In this work, we propose a novel spatio-temporal flow map layout to visualize when and where people from different locations move into the same places and make contact. We also propose integrating the spatiotemporal flow maps into existing spatiotemporal visualization techniques to form a suite of techniques for visualizing the movement and contact patterns. We report a potential application the proposed techniques can be applied to. The results show that our design and techniques properly unveil hidden information, while analysis can be achieved efficiently. Keywords: Spatio-temporal data, Flow map, Urban mobility

  13. BioenergyKDF: Enabling Spatiotemporal Data Synthesis and Research Collaboration

    Energy Technology Data Exchange (ETDEWEB)

    Myers, Aaron T [ORNL; Movva, Sunil [ORNL; Karthik, Rajasekar [ORNL; Bhaduri, Budhendra L [ORNL; White, Devin A [ORNL; Thomas, Neil [ORNL; Chase, Adrian S Z [ORNL

    2014-01-01

    The Bioenergy Knowledge Discovery Framework (BioenergyKDF) is a scalable, web-based collaborative environment for scientists working on bioenergy related research in which the connections between data, literature, and models can be explored and more clearly understood. The fully-operational and deployed system, built on multiple open source libraries and architectures, stores contributions from the community of practice and makes them easy to find, but that is just its base functionality. The BioenergyKDF provides a national spatiotemporal decision support capability that enables data sharing, analysis, modeling, and visualization as well as fosters the development and management of the U.S. bioenergy infrastructure, which is an essential component of the national energy infrastructure. The BioenergyKDF is built on a flexible, customizable platform that can be extended to support the requirements of any user community especially those that work with spatiotemporal data. While there are several community data-sharing software platforms available, some developed and distributed by national governments, none of them have the full suite of capabilities available in BioenergyKDF. For example, this component-based platform and database independent architecture allows it to be quickly deployed to existing infrastructure and to connect to existing data repositories (spatial or otherwise). As new data, analysis, and features are added; the BioenergyKDF will help lead research and support decisions concerning bioenergy into the future, but will also enable the development and growth of additional communities of practice both inside and outside of the Department of Energy. These communities will be able to leverage the substantial investment the agency has made in the KDF platform to quickly stand up systems that are customized to their data and research needs.

  14. UNDERSTANDING SEVERE WEATHER PROCESSES THROUGH SPATIOTEMPORAL RELATIONAL RANDOM FORESTS

    Data.gov (United States)

    National Aeronautics and Space Administration — UNDERSTANDING SEVERE WEATHER PROCESSES THROUGH SPATIOTEMPORAL RELATIONAL RANDOM FORESTS AMY MCGOVERN, TIMOTHY SUPINIE, DAVID JOHN GAGNE II, NATHANIEL TROUTMAN,...

  15. Spatiotemporal data visualisation for homecare monitoring of elderly people.

    Science.gov (United States)

    Juarez, Jose M; Ochotorena, Jose M; Campos, Manuel; Combi, Carlo

    2015-10-01

    Elderly people who live alone can be assisted by home monitoring systems that identify risk scenarios such as falls, fatigue symptoms or burglary. Given that these systems have to manage spatiotemporal data, human intervention is required to validate automatic alarms due to the high number of false positives and the need for context interpretation. The goal of this work was to provide tools to support human action, to identify such potential risk scenarios based on spatiotemporal data visualisation. We propose the MTA (multiple temporal axes) model, a visual representation of temporal information of the activity of a single person at different locations. The main goal of this model is to visualize the behaviour of a person in their home, facilitating the identification of health-risk scenarios and repetitive patterns. We evaluate the model's insight capacity compared with other models using a standard evaluation protocol. We also test its practical suitability of the MTA graphical model in a commercial home monitoring system. In particular, we implemented 8VISU, a visualization tool based on MTA. MTA proved to be more than 90% accurate in identify non-risk scenarios, independently of the length of the record visualised. When the spatial complexity was increased (e.g. number of rooms) the model provided good accuracy form up to 5 rooms. Therefore, user preferences and user performance seem to be balanced. Moreover, it also gave high sensitivity levels (over 90%) for 5-8 rooms. Fall is the most recurrent incident for elderly people. The MTA model outperformed the other models considered in identifying fall scenarios (66% of correctness) and was the second best for burglary and fatigue scenarios (36% of correctness). Our experiments also confirm the hypothesis that cyclic models are the most suitable for fatigue scenarios, the Spiral and MTA models obtaining most positive identifications. In home monitoring systems, spatiotemporal visualization is a useful tool for

  16. Frame rate vs resolution: A subjective evaluation of spatiotemporal perceived quality under varying computational budgets

    OpenAIRE

    Debattista, K.; Bugeja, K.; Spina, S.; Bashford-Rogers, T.; V. Hulusic

    2017-01-01

    Maximising performance for rendered content requires making compromises on quality parameters depending on the computational resources available. Yet, it is currently unclear which parameters best maximise perceived quality. This work investigates perceived quality across computational budgets for the primary spatio-temporal parameters of resolution and frame rate. Three experiments are conducted. Experiment 1 (n = 26) shows that participants prefer fixed frame rates of 60 frames per second (...

  17. Frame rate vs resolution : a subjective evaluation of spatiotemporal perceived quality under varying computational budgets

    OpenAIRE

    Debattista, Kurt; Bugeja, Keith; Spina, Sandro; Bashford-Rogers, Thomas; Hulusić, Vedad

    2017-01-01

    Maximizing performance for rendered content requires making compromises on quality parameters depending on the computational resources available . Yet, it is currently unclear which parameters best maximize perceived quality. This work investigates perceived quality across computational budgets for the primary spatiotemporal parameters of resolution and frame rate. Three experiments are conducted. Experiment 1 (n = 26) shows that participants prefer fixed frame rates of 60 frames per second (...

  18. On space, Its time, and Spatiotemporal Expressions

    DEFF Research Database (Denmark)

    Mylov, Peer

    2002-01-01

    From Introduction: "In the article Mylov particularly focuses on three aspects: he analyzes the body-based experience of space, which constitutes basic axes and frames of reference (up-down, left-right), and relations between body and objects in the surroundings. He looks at the relation between...... time and space, for instance as spatial representations of time ("we are getting close to dead­line" vs "deadline is getting close"). And, thirdly, he presents linguistic foundations of spatio-temporal issues and relations. All these issues are important for and must be taken into consideration when we...

  19. Spatio-temporal clustering of wildfires in Portugal

    Science.gov (United States)

    Costa, R.; Pereira, M. G.; Caramelo, L.; Vega Orozco, C.; Kanevski, M.

    2012-04-01

    Several studies have shown that wildfires in Portugal presenthigh temporal as well as high spatial variability (Pereira et al., 2005, 2011). The identification and characterization of spatio-temporal clusters contributes to a comprehensivecharacterization of the fire regime and to improve the efficiency of fire prevention and combat activities. The main goalsin this studyare: (i) to detect the spatio-temporal clusters of burned area; and, (ii) to characterize these clusters along with the role of human and environmental factors. The data were supplied by the National Forest Authority(AFN, 2011) and comprises: (a)the Portuguese Rural Fire Database, PRFD, (Pereira et al., 2011) for the 1980-2007period; and, (b) the national mapping burned areas between 1990 and 2009. In this work, in order to complement the more common cluster analysis algorithms, an alternative approach based onscan statistics and on the permutation modelwas used. This statistical methodallows the detection of local excess events and to test if such an excess can reasonably have occurred by chance.Results obtained for different simulations performed for different spatial and temporal windows are presented, compared and interpreted.The influence of several fire factors such as (climate, vegetation type, etc.) is also assessed. Pereira, M.G., Trigo, R.M., DaCamara, C.C., Pereira, J.M.C., Leite, S.M., 2005:"Synoptic patterns associated with large summer forest fires in Portugal".Agricultural and Forest Meteorology. 129, 11-25. Pereira, M. G., Malamud, B. D., Trigo, R. M., and Alves, P. I.: The history and characteristics of the 1980-2005 Portuguese rural fire database, Nat. Hazards Earth Syst. Sci., 11, 3343-3358, doi:10.5194/nhess-11-3343-2011, 2011 AFN, 2011: AutoridadeFlorestalNacional (National Forest Authority). Available at http://www.afn.min-agricultura.pt/portal.

  20. Asynchronous Visualization of Spatiotemporal Information for Multiple Moving Targets

    Science.gov (United States)

    Wang, Huadong

    2013-01-01

    In the modern information age, the quantity and complexity of spatiotemporal data is increasing both rapidly and continuously. Sensor systems with multiple feeds that gather multidimensional spatiotemporal data will result in information clusters and overload, as well as a high cognitive load for users of these systems. To meet future…

  1. Mining local climate data to assess spatiotemporal dengue fever epidemic patterns in French Guiana.

    Science.gov (United States)

    Flamand, Claude; Fabregue, Mickael; Bringay, Sandra; Ardillon, Vanessa; Quénel, Philippe; Desenclos, Jean-Claude; Teisseire, Maguelonne

    2014-10-01

    To identify local meteorological drivers of dengue fever in French Guiana, we applied an original data mining method to the available epidemiological and climatic data. Through this work, we also assessed the contribution of the data mining method to the understanding of factors associated with the dissemination of infectious diseases and their spatiotemporal spread. We applied contextual sequential pattern extraction techniques to epidemiological and meteorological data to identify the most significant climatic factors for dengue fever, and we investigated the relevance of the extracted patterns for the early warning of dengue outbreaks in French Guiana. The maximum temperature, minimum relative humidity, global brilliance, and cumulative rainfall were identified as determinants of dengue outbreaks, and the precise intervals of their values and variations were quantified according to the epidemiologic context. The strongest significant correlations were observed between dengue incidence and meteorological drivers after a 4-6-week lag. We demonstrated the use of contextual sequential patterns to better understand the determinants of the spatiotemporal spread of dengue fever in French Guiana. Future work should integrate additional variables and explore the notion of neighborhood for extracting sequential patterns. Dengue fever remains a major public health issue in French Guiana. The development of new methods to identify such specific characteristics becomes crucial in order to better understand and control spatiotemporal transmission. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  2. Using nonlinearity and spatiotemporal property modulation to control effective structural properties: dynamic rods

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel; Blekhman, Iliya I.

    2007-01-01

    the effective propagation speed of long waves by varying the amplitude of a superimposed high-frequency standing wave. It should be possible to change most properties related to structural stiffness, energy dissipation, and equilibrium states this way, by exploiting the general effects of stiffening, biasing......, and smoothening that characterize mechanically high-frequency excited structures. This work explores fundamental issues for spatiotemporally modulated nonlinear materials. First the effective stress-strain relation of a generally nonlinear material with a prescribed HF strain field is derived, discussed......, and exemplified. Then simple approximate analytical expressions are derived for the effective wave speed and natural frequencies for one-dimensional wave propagation in a nonlinear elastic rod, where the spatiotemporal modulation is imposed as a high-frequency standing wave, supposed to be given. Finally the more...

  3. Spatiotemporal integration of molecular and anatomical data in virtual reality using semantic mapping.

    Science.gov (United States)

    Soh, Jung; Turinsky, Andrei L; Trinh, Quang M; Chang, Jasmine; Sabhaney, Ajay; Dong, Xiaoli; Gordon, Paul Mk; Janzen, Ryan Pw; Hau, David; Xia, Jianguo; Wishart, David S; Sensen, Christoph W

    2009-01-01

    We have developed a computational framework for spatiotemporal integration of molecular and anatomical datasets in a virtual reality environment. Using two case studies involving gene expression data and pharmacokinetic data, respectively, we demonstrate how existing knowledge bases for molecular data can be semantically mapped onto a standardized anatomical context of human body. Our data mapping methodology uses ontological representations of heterogeneous biomedical datasets and an ontology reasoner to create complex semantic descriptions of biomedical processes. This framework provides a means to systematically combine an increasing amount of biomedical imaging and numerical data into spatiotemporally coherent graphical representations. Our work enables medical researchers with different expertise to simulate complex phenomena visually and to develop insights through the use of shared data, thus paving the way for pathological inference, developmental pattern discovery and biomedical hypothesis testing.

  4. Spatiotemporal Dynamic of Two-dimensional core annular flow in square channel

    Directory of Open Access Journals (Sweden)

    Nsom B.

    2013-04-01

    Full Text Available In this work, we study the spatiotemporal dynamics of a two-dimensional core-annular flow (CAF in a square channel of an oil/water system. The flow rate of oil is fixed at Qo=0.19 l/s and the flow rate of water Qw is varied from 0.20 l/s to 0.46 l/s. For large values of Qw (typically Qw>0.23l/s, the CAF is unstable, and it becomes stable for low values of Qw (typically Qw<0.23l/s. The spatiotemporal diagram technique is used to determine the characteristics of the water-oil interface, namely the entry length, height, parallel length, frequency, wavenumber, phase velocity, amplitude and spatial growth rate of wave amplitudeas function of the water flow rate Qw. Theses characteristics are used to explain the pressure drop as function of the water flow rate.

  5. Real time eye tracking using Kalman extended spatio-temporal context learning

    Science.gov (United States)

    Munir, Farzeen; Minhas, Fayyaz ul Amir Asfar; Jalil, Abdul; Jeon, Moongu

    2017-06-01

    Real time eye tracking has numerous applications in human computer interaction such as a mouse cursor control in a computer system. It is useful for persons with muscular or motion impairments. However, tracking the movement of the eye is complicated by occlusion due to blinking, head movement, screen glare, rapid eye movements, etc. In this work, we present the algorithmic and construction details of a real time eye tracking system. Our proposed system is an extension of Spatio-Temporal context learning through Kalman Filtering. Spatio-Temporal Context Learning offers state of the art accuracy in general object tracking but its performance suffers due to object occlusion. Addition of the Kalman filter allows the proposed method to model the dynamics of the motion of the eye and provide robust eye tracking in cases of occlusion. We demonstrate the effectiveness of this tracking technique by controlling the computer cursor in real time by eye movements.

  6. A Flexible Spatio-Temporal Model for Air Pollution with Spatial and Spatio-Temporal Covariates.

    Science.gov (United States)

    Lindström, Johan; Szpiro, Adam A; Sampson, Paul D; Oron, Assaf P; Richards, Mark; Larson, Tim V; Sheppard, Lianne

    2014-09-01

    The development of models that provide accurate spatio-temporal predictions of ambient air pollution at small spatial scales is of great importance for the assessment of potential health effects of air pollution. Here we present a spatio-temporal framework that predicts ambient air pollution by combining data from several different monitoring networks and deterministic air pollution model(s) with geographic information system (GIS) covariates. The model presented in this paper has been implemented in an R package, SpatioTemporal, available on CRAN. The model is used by the EPA funded Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air) to produce estimates of ambient air pollution; MESA Air uses the estimates to investigate the relationship between chronic exposure to air pollution and cardiovascular disease. In this paper we use the model to predict long-term average concentrations of NOx in the Los Angeles area during a ten year period. Predictions are based on measurements from the EPA Air Quality System, MESA Air specific monitoring, and output from a source dispersion model for traffic related air pollution (Caline3QHCR). Accuracy in predicting long-term average concentrations is evaluated using an elaborate cross-validation setup that accounts for a sparse spatio-temporal sampling pattern in the data, and adjusts for temporal effects. The predictive ability of the model is good with cross-validated R2 of approximately 0.7 at subject sites. Replacing four geographic covariate indicators of traffic density with the Caline3QHCR dispersion model output resulted in very similar prediction accuracy from a more parsimonious and more interpretable model. Adding traffic-related geographic covariates to the model that included Caline3QHCR did not further improve the prediction accuracy.

  7. Associative memory with spatiotemporal chaos control

    Science.gov (United States)

    Kushibe, Masanori; Liu, Yun; Ohtsubo, Junji

    1996-05-01

    Control of spatiotemporal chaos in a neural network with discrete time and continuous state variables is investigated. The chaos control is performed with the knowledge of only a part of the target information in the memory patterns. The success rate for the pattern associations and the dependence of the search time on the sampling number in the proposed chaos neural network are studied. By the introduction of the reinforcement factor in the learning process, the recognition rate of the network can be much enhanced. Random and regular samplings of the pattern for the control are tested and the successful results of the associations are demonstrated. The chaotic behavior and recalling ability of the system are evaluated based on the analysis of the Lyapunov spectrum of the network.

  8. Spatiotemporal dynamics of counterpropagating Airy beams

    Science.gov (United States)

    Wiersma, Noémi; Marsal, Nicolas; Sciamanna, Marc; Wolfersberger, Delphine

    2015-01-01

    We analyse theoretically the spatiotemporal dynamics of two incoherent counterpropagating Airy beams interacting in a photorefractive crystal under focusing conditions. For a large enough nonlinearity strength the interaction between the two Airy beams leads to light-induced waveguiding. The stability of the waveguide is determined by the crystal length, the nonlinearity strength and the beam’s intensities and is improved when comparing to the situation using Gaussian beams. We further identify the threshold above which the waveguide is no longer static but evolves dynamically either time-periodically or even chaotically. Above the stability threshold, each Airy-soliton moves erratically between privileged output positions that correspond to the spatial positions of the lobes of the counterpropagating Airy beam. These results suggest new ways of creating dynamically varying waveguides, optical logic gates and chaos-based computing. PMID:26315530

  9. Using R for large spatiotemporal data sets

    Science.gov (United States)

    Pebesma, Edzer

    2017-04-01

    Writing and sharing scientific software is a means to communicate scientific ideas for finding scientific consensus, no more and no less than writing and sharing scientific papers is. Important factors for successful communication are adopting an open source environment, and using a language that is understood by many. For many scientist, R's combination of rich data abstraction and highly exposed data structures makes it an attractive communication tool. This paper discusses the development of spatial and spatiotemporal data handling and analysis with R since 2000, and will point to some of R's strengths and weaknesses in a historical perspective. We will also discuss a new, S3-based package for feature data ("Simple Features for R"), and point to a way forward into the data science realm, where pipeline-based workflows are assumed. Finally, we will discuss how, in a similar vein, massive satellite or climate model data sets, potentially held in a cloud environment, can be handled and analyzed with R.

  10. Spatiotemporal dynamics of counterpropagating Airy beams

    Science.gov (United States)

    Wiersma, Noémi; Marsal, Nicolas; Sciamanna, Marc; Wolfersberger, Delphine

    2015-08-01

    We analyse theoretically the spatiotemporal dynamics of two incoherent counterpropagating Airy beams interacting in a photorefractive crystal under focusing conditions. For a large enough nonlinearity strength the interaction between the two Airy beams leads to light-induced waveguiding. The stability of the waveguide is determined by the crystal length, the nonlinearity strength and the beam’s intensities and is improved when comparing to the situation using Gaussian beams. We further identify the threshold above which the waveguide is no longer static but evolves dynamically either time-periodically or even chaotically. Above the stability threshold, each Airy-soliton moves erratically between privileged output positions that correspond to the spatial positions of the lobes of the counterpropagating Airy beam. These results suggest new ways of creating dynamically varying waveguides, optical logic gates and chaos-based computing.

  11. Secure communication based on spatiotemporal chaos

    Science.gov (United States)

    Ren, Hai-Peng; Bai, Chao

    2015-08-01

    In this paper, we propose a novel approach to secure communication based on spatiotemporal chaos. At the transmitter end, the state variables of the coupled map lattice system are divided into two groups: one is used as the key to encrypt the plaintext in the N-shift encryption function, and the other is used to mix with the output of the N-shift function to further confuse the information to transmit. At the receiver end, the receiver lattices are driven by the received signal to synchronize with the transmitter lattices and an inverse procedure of the encoding is conducted to decode the information. Numerical simulation and experiment based on the TI TMS320C6713 Digital Signal Processor (DSP) show the feasibility and the validity of the proposed scheme. Project supported by the National Natural Science Foundation of China (Grant No. 61172070) and the Funds from the Science and Technology Innovation Team of Shaanxi Province, China (Grant No. 2013CKT-04).

  12. Bilinearity in spatiotemporal integration of synaptic inputs.

    Directory of Open Access Journals (Sweden)

    Songting Li

    2014-12-01

    Full Text Available Neurons process information via integration of synaptic inputs from dendrites. Many experimental results demonstrate dendritic integration could be highly nonlinear, yet few theoretical analyses have been performed to obtain a precise quantitative characterization analytically. Based on asymptotic analysis of a two-compartment passive cable model, given a pair of time-dependent synaptic conductance inputs, we derive a bilinear spatiotemporal dendritic integration rule. The summed somatic potential can be well approximated by the linear summation of the two postsynaptic potentials elicited separately, plus a third additional bilinear term proportional to their product with a proportionality coefficient [Formula: see text]. The rule is valid for a pair of synaptic inputs of all types, including excitation-inhibition, excitation-excitation, and inhibition-inhibition. In addition, the rule is valid during the whole dendritic integration process for a pair of synaptic inputs with arbitrary input time differences and input locations. The coefficient [Formula: see text] is demonstrated to be nearly independent of the input strengths but is dependent on input times and input locations. This rule is then verified through simulation of a realistic pyramidal neuron model and in electrophysiological experiments of rat hippocampal CA1 neurons. The rule is further generalized to describe the spatiotemporal dendritic integration of multiple excitatory and inhibitory synaptic inputs. The integration of multiple inputs can be decomposed into the sum of all possible pairwise integration, where each paired integration obeys the bilinear rule. This decomposition leads to a graph representation of dendritic integration, which can be viewed as functionally sparse.

  13. Spatiotemporal complexity of the aortic sinus vortex

    Science.gov (United States)

    Moore, Brandon; Dasi, Lakshmi Prasad

    2014-07-01

    The aortic sinus vortex is a classical flow structure of significant importance to aortic valve dynamics and the initiation and progression of calcific aortic valve disease. We characterize the spatiotemporal characteristics of aortic sinus vortex dynamics in relation to the viscosity of blood analog solution as well as heart rate. High-resolution time-resolved (2 kHz) particle image velocimetry was conducted to capture 2D particle streak videos and 2D instantaneous velocity and streamlines along the sinus midplane using a physiological but rigid aorta model fitted with a porcine bioprosthetic heart valve. Blood analog fluids used include a water-glycerin mixture and saline to elucidate the sensitivity of vortex dynamics to viscosity. Experiments were conducted to record 10 heart beats for each combination of blood analog and heart rate condition. Results show that the topological characteristics of the velocity field vary in timescales as revealed using time bin-averaged vectors and corresponding instantaneous streamlines. There exist small timescale vortices and a large timescale main vortex. A key flow structure observed is the counter vortex at the upstream end of the sinus adjacent to the base (lower half) of the leaflet. The spatiotemporal complexity of vortex dynamics is shown to be profoundly influenced by strong leaflet flutter during systole with a peak frequency of 200 Hz and peak amplitude of 4 mm observed in the saline case. While fluid viscosity influences the length and timescales as well as the introduction of leaflet flutter, heart rate influences the formation of counter vortex at the upstream end of the sinus. Higher heart rates are shown to reduce the strength of the counter vortex that can greatly influence the directionality and strength of shear stresses along the base of the leaflet. This study demonstrates the impact of heart rate and blood analog viscosity on aortic sinus hemodynamics.

  14. Principles for statistical inference on big spatio-temporal data from climate models

    KAUST Repository

    Castruccio, Stefano

    2018-02-24

    The vast increase in size of modern spatio-temporal datasets has prompted statisticians working in environmental applications to develop new and efficient methodologies that are still able to achieve inference for nontrivial models within an affordable time. Climate model outputs push the limits of inference for Gaussian processes, as their size can easily be larger than 10 billion data points. Drawing from our experience in a set of previous work, we provide three principles for the statistical analysis of such large datasets that leverage recent methodological and computational advances. These principles emphasize the need of embedding distributed and parallel computing in the inferential process.

  15. Brain areas involved in spatial working memory.

    NARCIS (Netherlands)

    Asselen, M. van; Kessels, R.P.C.; Neggers, S.F.W.; Kappelle, L.J.; Frijns, C.J.M.; Postma, A.

    2006-01-01

    Spatial working memory entails the ability to keep spatial information active in working memory over a short period of time. To study the areas of the brain that are involved in spatial working memory, a group of stroke patients was tested with a spatial search task. Patients and healthy controls

  16. Optimizing Cruising Routes for Taxi Drivers Using a Spatio-Temporal Trajectory Model

    Directory of Open Access Journals (Sweden)

    Liang Wu

    2017-11-01

    Full Text Available Much of the taxi route-planning literature has focused on driver strategies for finding passengers and determining the hot spot pick-up locations using historical global positioning system (GPS trajectories of taxis based on driver experience, distance from the passenger drop-off location to the next passenger pick-up location and the waiting times at recommended locations for the next passenger. The present work, however, considers the average taxi travel speed mined from historical taxi GPS trajectory data and the allocation of cruising routes to more than one taxi driver in a small-scale region to neighboring pick-up locations. A spatio-temporal trajectory model with load balancing allocations is presented to not only explore pick-up/drop-off information but also provide taxi drivers with cruising routes to the recommended pick-up locations. In simulation experiments, our study shows that taxi drivers using cruising routes recommended by our spatio-temporal trajectory model can significantly reduce the average waiting time and travel less distance to quickly find their next passengers, and the load balancing strategy significantly alleviates road loads. These objective measures can help us better understand spatio-temporal traffic patterns and guide taxi navigation.

  17. Spatio-temporal Visualisation and Data Exploration of Traditional Ecological Knowledge/Indigenous Knowledge

    Directory of Open Access Journals (Sweden)

    Kierin Mackenzie

    2017-01-01

    Full Text Available Traditional Ecological Knowledge (TEK has been at the centre of mapping efforts for decades. Indigenous knowledge (IK is a critical subset of TEK, and Indigenous peoples utilise a wide variety of techniques for keeping track of time. Although techniques for mapping and visualising the temporal aspects of TEK/IK have been utilised, the spatio-temporal dimensions of TEK are not well explored visually outside of seasonal data and narrative approaches. Existing spatio-temporal models can add new visualisation approaches for TEK but are limited by ontological constraints regarding time, particularly the poor support for multi-cyclical data and localised timing. For TEK to be well represented, flexible systems are needed for modelling and mapping time that correspond well with traditional conceptions of time and space being supported. These approaches can take cues from previous spatio-temporal visualisation work in the Geographic(al Information System(s/Science(s GIS community, and from temporal depictions extant in existing cultural traditions.

  18. Spatiotemporal analysis of tropical disease research combining Europe PMC and affiliation mapping web services.

    Science.gov (United States)

    Palmblad, Magnus; Torvik, Vetle I

    2017-01-01

    Tropical medicine appeared as a distinct sub-discipline in the late nineteenth century, during a period of rapid European colonial expansion in Africa and Asia. After a dramatic drop after World War II, research on tropical diseases have received more attention and research funding in the twenty-first century. We used Apache Taverna to integrate Europe PMC and MapAffil web services, containing the spatiotemporal analysis workflow from a list of PubMed queries to a list of publication years and author affiliations geoparsed to latitudes and longitudes. The results could then be visualized in the Quantum Geographic Information System (QGIS). Our workflows automatically matched 253,277 affiliations to geographical coordinates for the first authors of 379,728 papers on tropical diseases in a single execution. The bibliometric analyses show how research output in tropical diseases follow major historical shifts in the twentieth century and renewed interest in and funding for tropical disease research in the twenty-first century. They show the effects of disease outbreaks, WHO eradication programs, vaccine developments, wars, refugee migrations, and peace treaties. Literature search and geoparsing web services can be combined in scientific workflows performing a complete spatiotemporal bibliometric analyses of research in tropical medicine. The workflows and datasets are freely available and can be used to reproduce or refine the analyses and test specific hypotheses or look into particular diseases or geographic regions. This work exceeds all previously published bibliometric analyses on tropical diseases in both scale and spatiotemporal range.

  19. Spatiotemporal meta-analysis: reviewing health psychology phenomena over space and time.

    Science.gov (United States)

    Johnson, Blair T; Cromley, Ellen K; Marrouch, Natasza

    2017-09-01

    Individual studies of health psychology are samples taken in particular places at particular times. The results of such studies manifest multiple processes, including those associated with individual, sample, intervention, and study design characteristics. Although extant meta-analyses of health phenomena have routinely considered these factors to explain heterogeneity, they have tended to neglect the environments where studies are conducted, which is ironic, as health phenomena cluster in space and times (e.g., epidemics). The settings in which study participants live, work, and recreate can be characterised by such environmental factors such as disease, weather, local and broad economic trends, the level of stigmatisation of minority groups, and allostatic load due to all causes. We introduce spatiotemporal meta-analysis, designed to address heterogeneity in study environments. We list potential challenges in developing spatiotemporal meta-analyses, and discuss future directions for this form of systematic reviewing methodology. Logically, to the extent that relevant spatiotemporal information on environmental conditions is available and varies widely, it can help to explain variability in study results that is not explained by individual, sample, study, or intervention features.

  20. Theta variation and spatiotemporal scaling along the septotemporal axis of the hippocampus

    Directory of Open Access Journals (Sweden)

    Lauren L Long

    2015-03-01

    Full Text Available Hippocampal theta has been related to locomotor speed, attention, anxiety, sensorimotor integration and memory among other emergent phenomena. One difficulty in understanding the function of theta is that the hippocampus (HPC modulates voluntary behavior at the same time that it processes sensory input. Both functions are correlated with characteristic changes in theta indices. The current review highlights a series of studies examining theta local field potential (LFP signals across the septotemporal or longitudinal axis of the HPC. While the theta signal is coherent throughout the entirety of the HPC, the amplitude, but not the frequency, of theta varies significantly across its three-dimensional expanse. We suggest that the theta signal offers a rich vein of information about how distributed neuronal ensembles support emergent function. Further, we speculate that emergent function across the long axis varies with respect to spatiotemporal scale. Thus, septal hippocampus processes details of the proximal spatiotemporal environment while more temporal aspects process larger spaces and wider time-scales. The degree to which emergent functions are supported by the synchronization of theta across the septotemporal axis is an open question. Our working model is that theta synchrony serves to bind ensembles representing varying resolutions of spatiotemporal information at interdependent septotemporal areas of the HPC. Such synchrony and cooperative interactions along the septotemporal axis likely support memory formation and subsequent consolidation and retrieval.

  1. DETERMINING SPATIO-TEMPORAL CADASTRAL DATA REQUIREMENT FOR INFRASTRUCTURE OF LADM FOR TURKEY

    Directory of Open Access Journals (Sweden)

    M. Alkan

    2016-06-01

    Full Text Available Nowadays, the nature of land title and cadastral (LTC data in the Turkey is dynamic from a temporal perspective which depends on the LTC operations. Functional requirements with respect to the characteristics are investigated based upon interviews of professionals in public and private sectors. These are; Legal authorities, Land Registry and Cadastre offices, Highway departments, Foundations, Ministries of Budget, Transportation, Justice, Public Works and Settlement, Environment and Forestry, Agriculture and Rural Affairs, Culture and Internal Affairs, State Institute of Statistics (SIS, execution offices, tax offices, real estate offices, private sector, local governments and banks. On the other hand, spatio-temporal LTC data very important component for creating infrastructure of Land Administration Model (LADM. For this reason, spatio-temporal LTC data needs for LADM not only updated but also temporal. The investigations ended up with determine temporal analyses of LTC data, traditional LTC system and tracing temporal analyses in traditional LTC system. In the traditional system, the temporal analyses needed by all these users could not be performed in a rapid and reliable way. The reason for this is that the traditional LTC system is a manual archiving system. The aims and general contents of this paper: (1 define traditional LTC system of Turkey; (2 determining the need for spatio-temporal LTC data and analyses for core domain model for LADM. As a results of temporal and spatio-temporal analysis LTC data needs, new system design is important for the Turkish LADM model. Designing and realizing an efficient and functional Temporal Geographic Information Systems (TGIS is inevitable for the Turkish LADM core infrastructure. Finally this paper outcome is creating infrastructure for design and develop LADM for Turkey.

  2. Spatiotemporal modelling and mapping of the bubonic plague epidemic in India

    Directory of Open Access Journals (Sweden)

    Christakos George

    2006-03-01

    Full Text Available Abstract Background This work studies the spatiotemporal evolution of bubonic plague in India during 1896–1906 using stochastic concepts and geographical information science techniques. In the past, most investigations focused on selected cities to conduct different kinds of studies, such as the ecology of rats. No detailed maps existed incorporating the space-time dependence structure and uncertainty sources of the epidemic system and providing a composite space-time picture of the disease propagation characteristics. Results Informative spatiotemporal maps were generated that represented mortality rates and geographical spread of the disease, and epidemic indicator plots were derived that offered meaningful characterizations of the spatiotemporal disease distribution. The bubonic plague in India exhibited strong seasonal and geographical features. During its entire duration, the plague continued to invade new geographical areas, while it followed a re-emergence pattern at many localities; its rate changed significantly during each year and the mortality distribution exhibited space-time heterogeneous patterns; prevalence usually occurred in the autumn and spring, whereas the plague stopped moving towards new locations during the summers. Conclusion Modern stochastic modelling and geographical information science provide powerful means to study the spatiotemporal distribution of the bubonic plague epidemic under conditions of uncertainty and multi-sourced databases; to account for various forms of interdisciplinary knowledge; and to generate informative space-time maps of mortality rates and propagation patterns. To the best of our knowledge, this kind of plague maps and plots become available for the first time, thus providing novel perspectives concerning the distribution and space-time propagation of the deadly epidemic. Furthermore, systematic maps and indicator plots make possible the comparison of the spatial-temporal propagation

  3. Determining Spatio-Temporal Cadastral Data Requirement for Infrastructure of Ladm for Turkey

    Science.gov (United States)

    Alkan, M.; Polat, Z. A.

    2016-06-01

    Nowadays, the nature of land title and cadastral (LTC) data in the Turkey is dynamic from a temporal perspective which depends on the LTC operations. Functional requirements with respect to the characteristics are investigated based upon interviews of professionals in public and private sectors. These are; Legal authorities, Land Registry and Cadastre offices, Highway departments, Foundations, Ministries of Budget, Transportation, Justice, Public Works and Settlement, Environment and Forestry, Agriculture and Rural Affairs, Culture and Internal Affairs, State Institute of Statistics (SIS), execution offices, tax offices, real estate offices, private sector, local governments and banks. On the other hand, spatio-temporal LTC data very important component for creating infrastructure of Land Administration Model (LADM). For this reason, spatio-temporal LTC data needs for LADM not only updated but also temporal. The investigations ended up with determine temporal analyses of LTC data, traditional LTC system and tracing temporal analyses in traditional LTC system. In the traditional system, the temporal analyses needed by all these users could not be performed in a rapid and reliable way. The reason for this is that the traditional LTC system is a manual archiving system. The aims and general contents of this paper: (1) define traditional LTC system of Turkey; (2) determining the need for spatio-temporal LTC data and analyses for core domain model for LADM. As a results of temporal and spatio-temporal analysis LTC data needs, new system design is important for the Turkish LADM model. Designing and realizing an efficient and functional Temporal Geographic Information Systems (TGIS) is inevitable for the Turkish LADM core infrastructure. Finally this paper outcome is creating infrastructure for design and develop LADM for Turkey.

  4. Spatiotemporal modelling and mapping of the bubonic plague epidemic in India.

    Science.gov (United States)

    Yu, Hwa-Lung; Christakos, George

    2006-03-17

    This work studies the spatiotemporal evolution of bubonic plague in India during 1896-1906 using stochastic concepts and geographical information science techniques. In the past, most investigations focused on selected cities to conduct different kinds of studies, such as the ecology of rats. No detailed maps existed incorporating the space-time dependence structure and uncertainty sources of the epidemic system and providing a composite space-time picture of the disease propagation characteristics. Informative spatiotemporal maps were generated that represented mortality rates and geographical spread of the disease, and epidemic indicator plots were derived that offered meaningful characterizations of the spatiotemporal disease distribution. The bubonic plague in India exhibited strong seasonal and geographical features. During its entire duration, the plague continued to invade new geographical areas, while it followed a re-emergence pattern at many localities; its rate changed significantly during each year and the mortality distribution exhibited space-time heterogeneous patterns; prevalence usually occurred in the autumn and spring, whereas the plague stopped moving towards new locations during the summers. Modern stochastic modelling and geographical information science provide powerful means to study the spatiotemporal distribution of the bubonic plague epidemic under conditions of uncertainty and multi-sourced databases; to account for various forms of interdisciplinary knowledge; and to generate informative space-time maps of mortality rates and propagation patterns. To the best of our knowledge, this kind of plague maps and plots become available for the first time, thus providing novel perspectives concerning the distribution and space-time propagation of the deadly epidemic. Furthermore, systematic maps and indicator plots make possible the comparison of the spatial-temporal propagation patterns of different diseases.

  5. Neighborhood detection for the identification of spatiotemporal systems.

    Science.gov (United States)

    Pan, Y; Billings, S A

    2008-06-01

    Neighborhood detection and local state vector construction for the identification of spatiotemporal systems is considered in this paper. Determining the neighborhood size both in the space and time domain can considerably reduce the complexity of the set of candidate model terms for the identification of coupled map lattice models. The computation requirements of the model identification algorithm can also be greatly reduced instead of the more direct identification approach of searching over the entire spatiotemporal neighborhood in the original space. In this paper, a new neighborhood detection method is introduced based on embedding theory for nonlinear dynamical systems to produce an initial spatiotemporal neighborhood for the identification of spatiotemporal systems. Numerical examples are provided to demonstrate the feasibility and applicability of the new neighborhood detection method.

  6. Spatio-temporal distribution of the infestations of ...

    African Journals Online (AJOL)

    Spatio-temporal distribution of the infestations of Coelaenomenodera lameensis Berti and Mariau ( Coleoptera, Chrysomelidae ) an oil palm tree ( Elaeis guineensis Jacq.) pest in Toumanguié (Côte d'Ivoire)

  7. Spatiotemporal modeling of WNV in mosquitoes in Suffolk County

    Data.gov (United States)

    U.S. Environmental Protection Agency — R code and dataset to produce spatial models. This dataset is associated with the following publication: Meyer, M., S. Campbell, and J. Johnston. Spatiotemporal...

  8. Exploring the spatio-temporal neural basis of face learning.

    Science.gov (United States)

    Yang, Ying; Xu, Yang; Jew, Carol A; Pyles, John A; Kass, Robert E; Tarr, Michael J

    2017-06-01

    Humans are experts at face individuation. Although previous work has identified a network of face-sensitive regions and some of the temporal signatures of face processing, as yet, we do not have a clear understanding of how such face-sensitive regions support learning at different time points. To study the joint spatio-temporal neural basis of face learning, we trained subjects to categorize two groups of novel faces and recorded their neural responses using magnetoencephalography (MEG) throughout learning. A regression analysis of neural responses in face-sensitive regions against behavioral learning curves revealed significant correlations with learning in the majority of the face-sensitive regions in the face network, mostly between 150-250 ms, but also after 300 ms. However, the effect was smaller in nonventral regions (within the superior temporal areas and prefrontal cortex) than that in the ventral regions (within the inferior occipital gyri (IOG), midfusiform gyri (mFUS) and anterior temporal lobes). A multivariate discriminant analysis also revealed that IOG and mFUS, which showed strong correlation effects with learning, exhibited significant discriminability between the two face categories at different time points both between 150-250 ms and after 300 ms. In contrast, the nonventral face-sensitive regions, where correlation effects with learning were smaller, did exhibit some significant discriminability, but mainly after 300 ms. In sum, our findings indicate that early and recurring temporal components arising from ventral face-sensitive regions are critically involved in learning new faces.

  9. Mobile technologies and the spatiotemporal configurations of institutional practice

    DEFF Research Database (Denmark)

    Shklovski, Irina; Troshynski, Emily; Dourish, Paul

    2015-01-01

    One of the most significant contemporary technological trends is institutional adoption and use of mobile and location-based systems and services. We argue that the notion of “location” as it manifests itself in location-based systems is being produced as an object of exchange. Here we are specif......One of the most significant contemporary technological trends is institutional adoption and use of mobile and location-based systems and services. We argue that the notion of “location” as it manifests itself in location-based systems is being produced as an object of exchange. Here we...... are specifically concerned with what happens to institutional roles, power relationships, and decision-making processes when a particular type of information—that of spatiotemporal location of people—is made into a technologically tradable object through the use of location-based systems. We examine...... the introduction of GPS (Global Positioning Systems) technologies by the California criminal justice system and the institution of parole for monitoring the movements of parolees, with consequences both for the everyday lives of these parolees and the work practices of their parole officers. We document the ways...

  10. Flying Focus: Spatiotemporal Control of the Laser Beam Intensity

    Science.gov (United States)

    Froula, D. H.; Turnbull, D.; Kessler, T. J.; Haberberger, D.; Bahk, S.-W.; Begishev, I. A.; Boni, R.; Bucht, S.; Davies, A.; Katz, J.; Sefkow, A. B.; Shaw, J. L.

    2017-10-01

    A ``flying focus'' is presented: this advanced focusing scheme provides unprecedented spatiotemporal control over the laser focal volume. A chromatic focusing system combined with chirped laser pulses enabled the speed of a small-diameter laser focus to propagate over nearly 100 × its Rayleigh length. Furthermore, the flying focus decouples the speed at which the peak intensity propagates from the group velocity of the laser pulse, allowing the laser focus to co- or counter-propagate along its axis at any velocity. Experiments have demonstrated a nearly constant intensity over 4.5 mm while the velocity of the focus ranged from subluminal (0.01 c) to superluminal (15 c) . These properties could provide the opportunity to overcome current fundamental limitations in laser-plasma amplifiers, laser-wakefield accelerators, photon accelerators, ion accelerators, and high-order frequency conversion. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  11. Spatiotemporal hydrological patterns in the landscape: Water quality implications

    Science.gov (United States)

    Walter, M.; Lyon, S.; Steenhuis, T. S.; Seifert, S. L.

    2006-05-01

    Linking spatiotemporally varying hydrologic processes and streamwater quality remains an important research challenge and a critical knowledge gap for improving management strategies. Indeed, the very term "nonpoint source pollution" implies that we cannot generally identify specific flowpaths connecting streams with their surrounding watersheds. Areas where the soil is saturated to the surface play important roles in terrestrial biogeochemistry and watershed hydrology, especially in humid, well-vegetated areas, like the northeastern US. In this talk we present an overview of our work to identify and predict the spatial and temporal distributions of surface saturation and to improve our understanding of how these areas impact water quality. We are finding that areas especially prone to saturation, i.e., hydrologically sensitive areas, account for a disproportionately large fraction of storm runoff and nutrient loss. We suggest targeting these areas when developing water quality protection strategies and will present some recent examples. As our understanding of the relevant hydrological and biogeochemical processes controlling water quality improves, we are making simultaneous improvements in the tools available for environmental-protection professionals, taking advantage of new technologies. At the same time, technological advances in areas like molecular biogeochemistry and nanotechnology are providing exciting new opportunities to investigate landscape hydrological and transport dynamics.

  12. Spatiotemporal Dynamics of Virus Infection Spreading in Tissues

    Science.gov (United States)

    Meyerhans, Andreas; Bessonov, Nickolai; Trofimchuk, Sergei; Volpert, Vitaly

    2016-01-01

    Virus spreading in tissues is determined by virus transport, virus multiplication in host cells and the virus-induced immune response. Cytotoxic T cells remove infected cells with a rate determined by the infection level. The intensity of the immune response has a bell-shaped dependence on the concentration of virus, i.e., it increases at low and decays at high infection levels. A combination of these effects and a time delay in the immune response determine the development of virus infection in tissues like spleen or lymph nodes. The mathematical model described in this work consists of reaction-diffusion equations with a delay. It shows that the different regimes of infection spreading like the establishment of a low level infection, a high level infection or a transition between both are determined by the initial virus load and by the intensity of the immune response. The dynamics of the model solutions include simple and composed waves, and periodic and aperiodic oscillations. The results of analytical and numerical studies of the model provide a systematic basis for a quantitative understanding and interpretation of the determinants of the infection process in target organs and tissues from the image-derived data as well as of the spatiotemporal mechanisms of viral disease pathogenesis, and have direct implications for a biopsy-based medical testing of the chronic infection processes caused by viruses, e.g. HIV, HCV and HBV. PMID:27997613

  13. Sex & vision I: Spatio-temporal resolution

    Directory of Open Access Journals (Sweden)

    Abramov Israel

    2012-09-01

    Full Text Available Abstract Background Cerebral cortex has a very large number of testosterone receptors, which could be a basis for sex differences in sensory functions. For example, audition has clear sex differences, which are related to serum testosterone levels. Of all major sensory systems only vision has not been examined for sex differences, which is surprising because occipital lobe (primary visual projection area may have the highest density of testosterone receptors in the cortex. We have examined a basic visual function: spatial and temporal pattern resolution and acuity. Methods We tested large groups of young adults with normal vision. They were screened with a battery of standard tests that examined acuity, color vision, and stereopsis. We sampled the visual system’s contrast-sensitivity function (CSF across the entire spatio-temporal space: 6 spatial frequencies at each of 5 temporal rates. Stimuli were gratings with sinusoidal luminance profiles generated on a special-purpose computer screen; their contrast was also sinusoidally modulated in time. We measured threshold contrasts using a criterion-free (forced-choice, adaptive psychophysical method (QUEST algorithm. Also, each individual’s acuity limit was estimated by fitting his or her data with a model and extrapolating to find the spatial frequency corresponding to 100% contrast. Results At a very low temporal rate, the spatial CSF was the canonical inverted-U; but for higher temporal rates, the maxima of the spatial CSFs shifted: Observers lost sensitivity at high spatial frequencies and gained sensitivity at low frequencies; also, all the maxima of the CSFs shifted by about the same amount in spatial frequency. Main effect: there was a significant (ANOVA sex difference. Across the entire spatio-temporal domain, males were more sensitive, especially at higher spatial frequencies; similarly males had significantly better acuity at all temporal rates. Conclusion As with other sensory systems

  14. Sex & vision I: Spatio-temporal resolution.

    Science.gov (United States)

    Abramov, Israel; Gordon, James; Feldman, Olga; Chavarga, Alla

    2012-09-04

    Cerebral cortex has a very large number of testosterone receptors, which could be a basis for sex differences in sensory functions. For example, audition has clear sex differences, which are related to serum testosterone levels. Of all major sensory systems only vision has not been examined for sex differences, which is surprising because occipital lobe (primary visual projection area) may have the highest density of testosterone receptors in the cortex. We have examined a basic visual function: spatial and temporal pattern resolution and acuity. We tested large groups of young adults with normal vision. They were screened with a battery of standard tests that examined acuity, color vision, and stereopsis. We sampled the visual system's contrast-sensitivity function (CSF) across the entire spatio-temporal space: 6 spatial frequencies at each of 5 temporal rates. Stimuli were gratings with sinusoidal luminance profiles generated on a special-purpose computer screen; their contrast was also sinusoidally modulated in time. We measured threshold contrasts using a criterion-free (forced-choice), adaptive psychophysical method (QUEST algorithm). Also, each individual's acuity limit was estimated by fitting his or her data with a model and extrapolating to find the spatial frequency corresponding to 100% contrast. At a very low temporal rate, the spatial CSF was the canonical inverted-U; but for higher temporal rates, the maxima of the spatial CSFs shifted: Observers lost sensitivity at high spatial frequencies and gained sensitivity at low frequencies; also, all the maxima of the CSFs shifted by about the same amount in spatial frequency. Main effect: there was a significant (ANOVA) sex difference. Across the entire spatio-temporal domain, males were more sensitive, especially at higher spatial frequencies; similarly males had significantly better acuity at all temporal rates. As with other sensory systems, there are marked sex differences in vision. The CSFs we measure

  15. Spatio-temporal evolution of forest fires in Portugal

    Science.gov (United States)

    Tonini, Marj; Pereira, Mário G.; Parente, Joana

    2017-04-01

    southern areas spread hot-spot are spatially randomly distributed and temporally more concentrated in the frame 2000 - 2004. To conclude, this study let us to identify a multitude of clustering space-time features of forest fires in Portugal, which can be useful for a better planning of educational activities and prevention campaigns as well as for a better allocation of monitoring systems and firefighting. References: Tonini M., Pereira M. G., Parente J. (2016) - Evolution of forest fires in Portugal: from spatio-temporal point events to smoothed density maps. Natural Hazard, doi:10.1007/s11069-016-2637-x Lu B., Harris P., Charlton M., Brunsdon C. (2014) - The GWmodel R package: further topics for exploring spatial heterogeneity using geographically weighted models. Geo-spatial Information Science, Vol. 17: 85-101 Rowlingson B., Diggle P., Bivand M.R. (2012) - Splancs: spatial point pattern analysis code in S-Plus. Computers and Geosciences, Vol. 19: 627-655 Acknowledgements: This work was supported by: (i) the FIREXTR project, PTDC/ATP¬GEO/0462/2014; (ii) the project Interact - Integrative Research in Environment,Agro-Chain and Technology, NORTE-01-0145-FEDER-000017, research line BEST, cofinanced by FEDER/NORTE 2020; and, (iii) European Investment Funds by FEDER/COMPETE/POCI-Operacional Competitiveness and Internacionalization Programme, under Project POCI-01-0145-FEDER-006958 and National Funds by FCT - Portuguese Foundation for Science and Technology, under the project UID/AGR/04033. We are especially grateful to ICNF for providing the fire.

  16. A bio-inspired system for spatio-temporal recognition in static and video imagery

    Science.gov (United States)

    Khosla, Deepak; Moore, Christopher K.; Chelian, Suhas

    2007-04-01

    This paper presents a bio-inspired method for spatio-temporal recognition in static and video imagery. It builds upon and extends our previous work on a bio-inspired Visual Attention and object Recognition System (VARS). The VARS approach locates and recognizes objects in a single frame. This work presents two extensions of VARS. The first extension is a Scene Recognition Engine (SCE) that learns to recognize spatial relationships between objects that compose a particular scene category in static imagery. This could be used for recognizing the category of a scene, e.g., office vs. kitchen scene. The second extension is the Event Recognition Engine (ERE) that recognizes spatio-temporal sequences or events in sequences. This extension uses a working memory model to recognize events and behaviors in video imagery by maintaining and recognizing ordered spatio-temporal sequences. The working memory model is based on an ARTSTORE1 neural network that combines an ART-based neural network with a cascade of sustained temporal order recurrent (STORE)1 neural networks. A series of Default ARTMAP classifiers ascribes event labels to these sequences. Our preliminary studies have shown that this extension is robust to variations in an object's motion profile. We evaluated the performance of the SCE and ERE on real datasets. The SCE module was tested on a visual scene classification task using the LabelMe2 dataset. The ERE was tested on real world video footage of vehicles and pedestrians in a street scene. Our system is able to recognize the events in this footage involving vehicles and pedestrians.

  17. Large dynamic characterizers of spatiotemporal intermittency

    Science.gov (United States)

    Gupte, Neelima

    2006-11-01

    Systems of coupled sine circle maps show regimes of spatiotemporally intermittent behaviour with associated scaling exponents which belong to the DP class, as well as regimes of spatially intermittent behaviour (with associated regular dynamical behaviour) which do not belong to the DP class. Both types of behaviour are seen along the bifurcation boundaries of the synchronized solutions, and contribute distinct signatures to the dynamical characterizers of the system, viz. the distribution of eigenvalues of the one step stability matrix. Within the spatially intermittent (SI) class, the temporal behaviour of the burst solutions can be quasi-periodic or travelling wave. The usual characterizers of bifurcations, i.e. the eigenvalues of the stability matrix crossing the unit circle, pick up the bifurcation from the synchronized solution to SI with quasi-periodic bursts but are unable to pick up the bifurcation of the synchronized solution to SI with TW bursts. Other characterizers, such as the Shannon entropy of the eigenvalue distribution, and the rate of change of the largest eigenvalue with parameter are required to pick up this bifurcation. This feature has also been seen for other bifurcations in this system, e.g. that from the synchronized solution to kink solutions. We therefore conjecture that in the case of high dimensional systems, entropic characterizers provide better signatures of bifurcations from one ordered solution to another.

  18. Spatiotemporal video deinterlacing using control grid interpolation

    Science.gov (United States)

    Venkatesan, Ragav; Zwart, Christine M.; Frakes, David H.; Li, Baoxin

    2015-03-01

    With the advent of progressive format display and broadcast technologies, video deinterlacing has become an important video-processing technique. Numerous approaches exist in the literature to accomplish deinterlacing. While most earlier methods were simple linear filtering-based approaches, the emergence of faster computing technologies and even dedicated video-processing hardware in display units has allowed higher quality but also more computationally intense deinterlacing algorithms to become practical. Most modern approaches analyze motion and content in video to select different deinterlacing methods for various spatiotemporal regions. We introduce a family of deinterlacers that employs spectral residue to choose between and weight control grid interpolation based spatial and temporal deinterlacing methods. The proposed approaches perform better than the prior state-of-the-art based on peak signal-to-noise ratio, other visual quality metrics, and simple perception-based subjective evaluations conducted by human viewers. We further study the advantages of using soft and hard decision thresholds on the visual performance.

  19. Spatiotemporal pattern of bacterioplankton in Donghu Lake

    Science.gov (United States)

    Zhang, Xiang; Yan, Qingyun; Yu, Yuhe; Dai, Lili

    2014-05-01

    Bacterioplankton play key roles in the biogeochemical cycle and in organic contaminant degradation. The species richness and abundance of bacterial subgroups are generally distinct from each other, and this is attributed to their different functions in aquatic ecosystems. The spatiotemporal variations of eight phylogenetic subgroups (Actinobacteria, Bacteroidetes, Cyanobacteria, Firmicutes, Planctomycetes, alpha-, beta-, and gamma-Proteobacteria) derived from Donghu Lake were investigated using PCR-DGGE fingerprinting, to explore their responses to environmental factors. Results indicate that Actinobacteria and beta-Proteobacteria were the two largest bacterial subgroups detected. These two groups and Bacteroidetes showed clear seasonal patterns in composition of the operational taxonomic unit. Results also suggest that the bacterioplankton subgroups in Donghu Lake were significantly correlated with different environmental factors. In brief, the total nitrogen was one of the major factors regulating all the bacterioplankton except for Actinobacteria. However, total phosphorus, another important eutrophication factor, contributed to the two largest bacterial groups (Actinobacteria and beta-Proteobacteria), as well as to the Cyanobacteria and Firmicutes. Therefore, the responses of bacterioplankton subgroups to environmental factors were different, and this should be attributed to the differences in the functions of different groups.

  20. Multisensory control of hippocampal spatiotemporal selectivity.

    Science.gov (United States)

    Ravassard, Pascal; Kees, Ashley; Willers, Bernard; Ho, David; Aharoni, Daniel A; Cushman, Jesse; Aghajan, Zahra M; Mehta, Mayank R

    2013-06-14

    The hippocampal cognitive map is thought to be driven by distal visual cues and self-motion cues. However, other sensory cues also influence place cells. Hence, we measured rat hippocampal activity in virtual reality (VR), where only distal visual and nonvestibular self-motion cues provided spatial information, and in the real world (RW). In VR, place cells showed robust spatial selectivity; however, only 20% were track active, compared with 45% in the RW. This indicates that distal visual and nonvestibular self-motion cues are sufficient to provide selectivity, but vestibular and other sensory cues present in RW are necessary to fully activate the place-cell population. In addition, bidirectional cells preferentially encoded distance along the track in VR, while encoding absolute position in RW. Taken together, these results suggest the differential contributions of these sensory cues in shaping the hippocampal population code. Theta frequency was reduced, and its speed dependence was abolished in VR, but phase precession was unaffected, constraining mechanisms governing both hippocampal theta oscillations and temporal coding. These results reveal cooperative and competitive interactions between sensory cues for control over hippocampal spatiotemporal selectivity and theta rhythm.

  1. Spatiotemporal characteristics of drought in Serbia

    Science.gov (United States)

    Gocic, Milan; Trajkovic, Slavisa

    2014-03-01

    The evaluation of spatiotemporal characteristics of drought was based on monthly precipitation data from 29 synoptic stations for the period of 1948-2012. The percent of normal precipitation was applied to illustrate the driest years in Serbia (1990, 2000, and 2011). The Standardized Precipitation Index (SPI) and S-mode principal component analysis (PCA) were used to capture the drought patterns. Agglomerative hierarchical cluster analysis was applied to identify three different drought sub-regions: (1) region R1 includes the north and the northeast part of Serbia; (2) region R2 includes the western part of Central Serbia and southwestern part of Serbia; and (3) region R3 includes central, east, south and southeast part of Serbia. The R2 had the monthly precipitation values above average, while R1 and R3 had the precipitation values under average of Serbia. The year 2000 was the driest and 1955 was the wettest during the observed period. The characteristics of drought were analyzed in terms of the temporal evolution of the SPI-12 values and the frequency of drought for the three identified regions. The percentage of years characterized by drought was 44.62% for R1, 50.77% for R2 and 46.15% for R3. Approximately 70% of the frequency of drought belongs to the near normal drought category.

  2. Spatiotemporal Dynamic of Two-dimensional core annular flow in square channel

    Science.gov (United States)

    Latrache, N.; Nsom, B.; Decruppe, J.-P.

    2013-04-01

    In this work, we study the spatiotemporal dynamics of a two-dimensional core-annular flow (CAF) in a square channel of an oil/water system. The flow rate of oil is fixed at Qo=0.19 l/s and the flow rate of water Qw is varied from 0.20 l/s to 0.46 l/s. For large values of Qw (typically Qw>0.23l/s), the CAF is unstable, and it becomes stable for low values of Qw (typically Qwflow rate Qw. Theses characteristics are used to explain the pressure drop as function of the water flow rate.

  3. Spatiotemporal Dynamic of Two-dimensional core annular flow in square channel

    OpenAIRE

    Nsom B.; Latrache N.; Decruppe J-P.

    2013-01-01

    In this work, we study the spatiotemporal dynamics of a two-dimensional core-annular flow (CAF) in a square channel of an oil/water system. The flow rate of oil is fixed at Qo=0.19 l/s and the flow rate of water Qw is varied from 0.20 l/s to 0.46 l/s. For large values of Qw (typically Qw>0.23l/s), the CAF is unstable, and it becomes stable for low values of Qw (typically Qw

  4. Spatio-Temporal Analysis of Human Activities in Indoor Environments through Mobile Sensing

    DEFF Research Database (Denmark)

    Prentow, Thor Siiger

    methods for spatio-temporal analysis of human activities in indoor environments based on mobile sensing. The methods aim to improve scheduling and facility utilization by providing information on the used route networks, transportation modes, travel times, and the flow of people through buildings......For large-scale outdoor and indoor operations, improvement of work task logistics is an important focus area. Efficient handling of work task logistics is especially crucial for operations involving spatially distributed work tasks, such as hospital service logistics, large-scale manufacturing...... plants, or airports. For spatially distributed tasks, delays in a single task may propagate to multiple other tasks, causing large amounts of wasted time. The planning and delegation of work tasks has traditionally been performed manually, using historical information on task execution combined...

  5. WORLD SPATIOTEMPORAL ANALYTICS AND MAPPING PROJECT (WSTAMP: DISCOVERING, EXPLORING, AND MAPPING SPATIOTEMPORAL PATTERNS ACROSS THE WORLD’S LARGEST OPEN SORUCE DATA SETS

    Directory of Open Access Journals (Sweden)

    R. Stewart

    2015-07-01

    Full Text Available The application of spatiotemporal (ST analytics to integrated data from major sources such as the World Bank, United Nations, and dozens of others holds tremendous potential for shedding new light on the evolution of cultural, health, economic, and geopolitical landscapes on a global level. Realizing this potential first requires an ST data model that addresses challenges in properly merging data from multiple authors, with evolving ontological perspectives, semantical differences, and changing attributes, as well as content that is textual, numeric, categorical, and hierarchical. Equally challenging is the development of analytical and visualization approaches that provide a serious exploration of this integrated data while remaining accessible to practitioners with varied backgrounds. The WSTAMP project at Oak Ridge National Laboratory has yielded two major results in addressing these challenges: 1 development of the WSTAMP database, a significant advance in ST data modeling that integrates 10,000+ attributes covering over 200 nation states spanning over 50 years from over 30 major sources and 2 a novel online ST exploratory and analysis tool providing an array of modern statistical and visualization techniques for analyzing these data temporally, spatially, and spatiotemporally under a standard analytic workflow. We discuss the status of this work and report on major findings.

  6. Spatiotemporal analysis of normal and pathological human vocal fold vibrations.

    Science.gov (United States)

    Krausert, Christopher R; Liang, Yufang; Zhang, Yu; Rieves, Adam L; Geurink, Kyle R; Jiang, Jack J

    2012-01-01

    For spatiotemporal analysis to become a relevant clinical tool, it must be applied to human vocal fold vibration. Receiver operating characteristic (ROC) analysis will help assess the ability of spatiotemporal parameters to detect pathological vibration. Spatiotemporal parameters of correlation length and entropy were extracted from high-speed videos of 124 subjects, 67 without vocal fold pathology and 57 with either vocal fold polyps or nodules. Mann-Whitney rank sum tests were performed to compare normal vocal fold vibrations to pathological vibrations, and ROC analysis was used to assess the diagnostic value of spatiotemporal analysis. A statistically significant difference was found between the normal and pathological groups in both correlation length (P nodules and polyps groups in either correlation length (P = .227) or entropy (P = .943). The ROC analysis showed an area under the curve of 0.63 for correlation length and 0.51 for entropy. Although they could not effectively distinguish vibration of vocal folds with nodules from those with polyps, the spatiotemporal parameters correlation length and entropy exhibit the ability to differentiate normal and pathological vocal fold vibration and may represent a diagnostic tool for objectively detecting abnormal vibration in the future, especially in neurological voice disorders and vocal folds without a visible lesion. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Learning-Based Video Superresolution Reconstruction Using Spatiotemporal Nonlocal Similarity

    Directory of Open Access Journals (Sweden)

    Meiyu Liang

    2015-01-01

    Full Text Available Aiming at improving the video visual resolution quality and details clarity, a novel learning-based video superresolution reconstruction algorithm using spatiotemporal nonlocal similarity is proposed in this paper. Objective high-resolution (HR estimations of low-resolution (LR video frames can be obtained by learning LR-HR correlation mapping and fusing spatiotemporal nonlocal similarities between video frames. With the objective of improving algorithm efficiency while guaranteeing superresolution quality, a novel visual saliency-based LR-HR correlation mapping strategy between LR and HR patches is proposed based on semicoupled dictionary learning. Moreover, aiming at improving performance and efficiency of spatiotemporal similarity matching and fusion, an improved spatiotemporal nonlocal fuzzy registration scheme is established using the similarity weighting strategy based on pseudo-Zernike moment feature similarity and structural similarity, and the self-adaptive regional correlation evaluation strategy. The proposed spatiotemporal fuzzy registration scheme does not rely on accurate estimation of subpixel motion, and therefore it can be adapted to complex motion patterns and is robust to noise and rotation. Experimental results demonstrate that the proposed algorithm achieves competitive superresolution quality compared to other state-of-the-art algorithms in terms of both subjective and objective evaluations.

  8. Spatiotemporal dynamics of argument retrieval and reordering: an FMRI and EEG study on sentence processing.

    Science.gov (United States)

    Meyer, Lars; Obleser, Jonas; Kiebel, Stefan J; Friederici, Angela D

    2012-01-01

    In sentence processing, it is still unclear how the neural language network successfully establishes argument-verb dependencies in its spatiotemporal neuronal dynamics. Previous work has suggested that the establishment of subject-verb and object-verb dependencies requires argument retrieval from working memory, and that dependency establishment in object-first sentences additionally necessitates argument reordering. We examine the spatiotemporal neuronal dynamics of the brain regions that subserve these sub-processes by crossing an argument reordering factor (i.e., subject-first versus object-first sentences) with an argument retrieval factor (i.e., short versus long argument-verb dependencies) in German. Using functional magnetic resonance imaging (fMRI), we found that reordering demands focally activate the left pars opercularis (Broca's area), while storage and retrieval demands activated left temporo-parietal (TP) regions. In addition, when analyzing the time course of fMRI-informed equivalent current dipole sources in the EEG at the subcategorizing verb, we found that activity in the TP-region occurs relatively early (40-180 ms), followed by activity in Broca's area (300-500 ms). These findings were matched by topographical correlation analyses of fMRI activations in EEG sensor space, showing that, in the scalp potential, TP-region activity surfaces as an early positivity and IFG activity as a later positivity in the scalp potential. These results provide fine-grained evidence for spatiotemporally separable sub-processes of argument retrieval and reordering in sentence processing.

  9. Bridge damage detection using spatiotemporal patterns extracted from dense sensor network

    Science.gov (United States)

    Liu, Chao; Gong, Yongqiang; Laflamme, Simon; Phares, Brent; Sarkar, Soumik

    2017-01-01

    The alarmingly degrading state of transportation infrastructures combined with their key societal and economic importance calls for automatic condition assessment methods to facilitate smart management of maintenance and repairs. With the advent of ubiquitous sensing and communication capabilities, scalable data-driven approaches is of great interest, as it can utilize large volume of streaming data without requiring detailed physical models that can be inaccurate and computationally expensive to run. Properly designed, a data-driven methodology could enable fast and automatic evaluation of infrastructures, discovery of causal dependencies among various sub-system dynamic responses, and decision making with uncertainties and lack of labeled data. In this work, a spatiotemporal pattern network (STPN) strategy built on symbolic dynamic filtering (SDF) is proposed to explore spatiotemporal behaviors in a bridge network. Data from strain gauges installed on two bridges are generated using finite element simulation for three types of sensor networks from a density perspective (dense, nominal, sparse). Causal relationships among spatially distributed strain data streams are extracted and analyzed for vehicle identification and detection, and for localization of structural degradation in bridges. Multiple case studies show significant capabilities of the proposed approach in: (i) capturing spatiotemporal features to discover causality between bridges (geographically close), (ii) robustness to noise in data for feature extraction, (iii) detecting and localizing damage via comparison of bridge responses to similar vehicle loads, and (iv) implementing real-time health monitoring and decision making work flow for bridge networks. Also, the results demonstrate increased sensitivity in detecting damages and higher reliability in quantifying the damage level with increase in sensor network density.

  10. Annual spatiotemporal migration schedules in three larger insectivorous birds

    DEFF Research Database (Denmark)

    Jacobsen, Lars Bo; Jensen, Niels Odder; Willemoes, Mikkel

    2017-01-01

    Background: Knowledge of spatiotemporal migration patterns is important for our understanding of migration ecology and ultimately conservation of migratory species. We studied the annual migration schedules of European nightjar, a large nocturnal insectivore and compared it with two other larger ...... for understanding spatiotemporal migration patterns and causes of declines in migratory species.......Background: Knowledge of spatiotemporal migration patterns is important for our understanding of migration ecology and ultimately conservation of migratory species. We studied the annual migration schedules of European nightjar, a large nocturnal insectivore and compared it with two other larger...... the annual migrations of nightjars and swifts and compared these with satellite tracking of cuckoo migration. Results: Individuals of the three species migrated to wintering grounds centered in Central Africa, except some common swifts that remained in West Africa, crossing or circumventing the Sahara along...

  11. Audio-Visual Speaker Diarization Based on Spatiotemporal Bayesian Fusion.

    Science.gov (United States)

    Gebru, Israel; Ba, Sileye; Li, Xiaofei; Horaud, Radu

    2017-01-05

    Speaker diarization consists of assigning speech signals to people engaged in a dialogue. An audio-visual spatiotemporal diarization model is proposed. The model is well suited for challenging scenarios that consist of several participants engaged in multi-party interaction while they move around and turn their heads towards the other participants rather than facing the cameras and the microphones. Multiple-person visual tracking is combined with multiple speech-source localization in order to tackle the speech-to-person association problem. The latter is solved within a novel audio-visual fusion method on the following grounds: binaural spectral features are first extracted from a microphone pair, then a supervised audio-visual alignment technique maps these features onto an image, and finally a semisupervised clustering method assigns binaural spectral features to visible persons. The main advantage of this method over previous work is that it processes in a principled way speech signals uttered simultaneously by multiple persons. The diarization itself is cast into a latent-variable temporal graphical model that infers speaker identities and speech turns, based on the output of an audio-visual association process, executed at each time slice, and on the dynamics of the diarization variable itself. The proposed formulation yields an efficient exact inference procedure. A novel dataset, that contains audio-visual training data as well as a number of scenarios involving several participants engaged in formal and informal dialogue, is introduced. The proposed method is thoroughly tested and benchmarked with respect to several state-of-the art diarization algorithms.

  12. Spatiotemporal dynamics of large-scale brain activity

    Science.gov (United States)

    Neuman, Jeremy

    Understanding the dynamics of large-scale brain activity is a tough challenge. One reason for this is the presence of an incredible amount of complexity arising from having roughly 100 billion neurons connected via 100 trillion synapses. Because of the extremely high number of degrees of freedom in the nervous system, the question of how the brain manages to properly function and remain stable, yet also be adaptable, must be posed. Neuroscientists have identified many ways the nervous system makes this possible, of which synaptic plasticity is possibly the most notable one. On the other hand, it is vital to understand how the nervous system also loses stability, resulting in neuropathological diseases such as epilepsy, a disease which affects 1% of the population. In the following work, we seek to answer some of these questions from two different perspectives. The first uses mean-field theory applied to neuronal populations, where the variables of interest are the percentages of active excitatory and inhibitory neurons in a network, to consider how the nervous system responds to external stimuli, self-organizes and generates epileptiform activity. The second method uses statistical field theory, in the framework of single neurons on a lattice, to study the concept of criticality, an idea borrowed from physics which posits that in some regime the brain operates in a collectively stable or marginally stable manner. This will be examined in two different neuronal networks with self-organized criticality serving as the overarching theme for the union of both perspectives. One of the biggest problems in neuroscience is the question of to what extent certain details are significant to the functioning of the brain. These details give rise to various spatiotemporal properties that at the smallest of scales explain the interaction of single neurons and synapses and at the largest of scales describe, for example, behaviors and sensations. In what follows, we will shed some

  13. Real-Time Earthquake Monitoring with Spatio-Temporal Fields

    Science.gov (United States)

    Whittier, J. C.; Nittel, S.; Subasinghe, I.

    2017-10-01

    With live streaming sensors and sensor networks, increasingly large numbers of individual sensors are deployed in physical space. Sensor data streams are a fundamentally novel mechanism to deliver observations to information systems. They enable us to represent spatio-temporal continuous phenomena such as radiation accidents, toxic plumes, or earthquakes almost as instantaneously as they happen in the real world. Sensor data streams discretely sample an earthquake, while the earthquake is continuous over space and time. Programmers attempting to integrate many streams to analyze earthquake activity and scope need to write code to integrate potentially very large sets of asynchronously sampled, concurrent streams in tedious application code. In previous work, we proposed the field stream data model (Liang et al., 2016) for data stream engines. Abstracting the stream of an individual sensor as a temporal field, the field represents the Earth's movement at the sensor position as continuous. This simplifies analysis across many sensors significantly. In this paper, we undertake a feasibility study of using the field stream model and the open source Data Stream Engine (DSE) Apache Spark(Apache Spark, 2017) to implement a real-time earthquake event detection with a subset of the 250 GPS sensor data streams of the Southern California Integrated GPS Network (SCIGN). The field-based real-time stream queries compute maximum displacement values over the latest query window of each stream, and related spatially neighboring streams to identify earthquake events and their extent. Further, we correlated the detected events with an USGS earthquake event feed. The query results are visualized in real-time.

  14. REAL-TIME EARTHQUAKE MONITORING WITH SPATIO-TEMPORAL FIELDS

    Directory of Open Access Journals (Sweden)

    J. C. Whittier

    2017-10-01

    Full Text Available With live streaming sensors and sensor networks, increasingly large numbers of individual sensors are deployed in physical space. Sensor data streams are a fundamentally novel mechanism to deliver observations to information systems. They enable us to represent spatio-temporal continuous phenomena such as radiation accidents, toxic plumes, or earthquakes almost as instantaneously as they happen in the real world. Sensor data streams discretely sample an earthquake, while the earthquake is continuous over space and time. Programmers attempting to integrate many streams to analyze earthquake activity and scope need to write code to integrate potentially very large sets of asynchronously sampled, concurrent streams in tedious application code. In previous work, we proposed the field stream data model (Liang et al., 2016 for data stream engines. Abstracting the stream of an individual sensor as a temporal field, the field represents the Earth’s movement at the sensor position as continuous. This simplifies analysis across many sensors significantly. In this paper, we undertake a feasibility study of using the field stream model and the open source Data Stream Engine (DSE Apache Spark(Apache Spark, 2017 to implement a real-time earthquake event detection with a subset of the 250 GPS sensor data streams of the Southern California Integrated GPS Network (SCIGN. The field-based real-time stream queries compute maximum displacement values over the latest query window of each stream, and related spatially neighboring streams to identify earthquake events and their extent. Further, we correlated the detected events with an USGS earthquake event feed. The query results are visualized in real-time.

  15. Modelling Spatio-Temporal Relevancy in Urban Context-Aware Pervasive Systems Using Voronoi Continuous Range Query and Multi-Interval Algebra

    Directory of Open Access Journals (Sweden)

    Najmeh Neysani Samany

    2013-01-01

    Full Text Available Space and time are two dominant factors in context-aware pervasive systems which determine whether an entity is related to the moving user or not. This paper specifically addresses the use of spatio-temporal relations for detecting spatio-temporally relevant contexts to the user. The main contribution of this work is that the proposed model is sensitive to the velocity and direction of the user and applies customized Multi Interval Algebra (MIA with Voronoi Continuous Range Query (VCRQ to introduce spatio-temporally relevant contexts according to their arrangement in space. In this implementation the Spatio-Temporal Relevancy Model for Context-Aware Systems (STRMCAS helps the tourist to find his/her preferred areas that are spatio-temporally relevant. The experimental results in a scenario of tourist navigation are evaluated with respect to the accuracy of the model, performance time and satisfaction of users in 30 iterations of the algorithm. The evaluation process demonstrated the efficiency of the model in real-world applications.

  16. Spatial eigenvector filtering for spatiotemporal crime mapping and spatial crime analysis

    NARCIS (Netherlands)

    Helbich, M; Jokar Arsanjani, J

    2015-01-01

    Spatial and spatiotemporal analyses are exceedingly relevant to determine criminogenic factors. The estimation of Poisson and negative binomial models (NBM) is complicated by spatial autocorrelation. Therefore, first, eigenvector spatial filtering (ESF) is introduced as a method for spatiotemporal

  17. Spatio-Temporal Data Mining for Location-Based Services

    DEFF Research Database (Denmark)

    Gidofalvi, Gyozo

    . The objectives of the presented thesis are three-fold. First, to extend popular data mining methods to the spatio-temporal domain. Second, to demonstrate the usefulness of the extended methods and the derived knowledge in promising LBS examples. Finally, to eliminate privacy concerns in connection with spatio......-temporal data mining by devising systems for privacy-preserving location data collection and mining.......Location-Based Services (LBS) are continuously gaining popularity. Innovative LBSes integrate knowledge about the users into the service. Such knowledge can be derived by analyzing the location data of users. Such data contain two unique dimensions, space and time, which need to be analyzed...

  18. Coexistence of collapse and stable spatiotemporal solitons in multimode fibers

    Science.gov (United States)

    Shtyrina, Olga V.; Fedoruk, Mikhail P.; Kivshar, Yuri S.; Turitsyn, Sergei K.

    2018-01-01

    We analyze spatiotemporal solitons in multimode optical fibers and demonstrate the existence of stable solitons, in a sharp contrast to earlier predictions of collapse of multidimensional solitons in three-dimensional media. We discuss the coexistence of blow-up solutions and collapse stabilization by a low-dimensional external potential in graded-index media, and also predict the existence of stable higher-order nonlinear waves such as dipole-mode spatiotemporal solitons. To support the main conclusions of our numerical studies we employ a variational approach and derive analytically the stability criterion for input powers for the collapse stabilization.

  19. Spatio-temporal databases complex motion pattern queries

    CERN Document Server

    Vieira, Marcos R

    2013-01-01

    This brief presents several new query processing techniques, called complex motion pattern queries, specifically designed for very large spatio-temporal databases of moving objects. The brief begins with the definition of flexible pattern queries, which are powerful because of the integration of variables and motion patterns. This is followed by a summary of the expressive power of patterns and flexibility of pattern queries. The brief then present the Spatio-Temporal Pattern System (STPS) and density-based pattern queries. STPS databases contain millions of records with information about mobi

  20. Spatiotemporal Information Organization and Visualization on Tidal Level

    Science.gov (United States)

    Huang, B.; Zhang, Y.; Wang, Y.; Liu, Q.

    2015-07-01

    The amount and location of oceanographic stations vary in different time and the observation information of the same station shows temporality. Hence, ocean observation information has strong spatiotemporal characteristics. This article firstly introduces storage strategy and representation method of spatiotemporal information on tidal level. Then the prototype system was built with the ability of storing, updating, analyzing, and early warning of tidal level in Shandong Peninsula of China. The system achieves the inquiry and visualization of realtime and historical information of oceanographic stations, which provides technical support for oceanographers and decisionmakers.

  1. Tensor analysis methods for activity characterization in spatiotemporal data

    Energy Technology Data Exchange (ETDEWEB)

    Haass, Michael Joseph; Van Benthem, Mark Hilary; Ochoa, Edward M

    2014-03-01

    Tensor (multiway array) factorization and decomposition offers unique advantages for activity characterization in spatio-temporal datasets because these methods are compatible with sparse matrices and maintain multiway structure that is otherwise lost in collapsing for regular matrix factorization. This report describes our research as part of the PANTHER LDRD Grand Challenge to develop a foundational basis of mathematical techniques and visualizations that enable unsophisticated users (e.g. users who are not steeped in the mathematical details of matrix algebra and mulitway computations) to discover hidden patterns in large spatiotemporal data sets.

  2. Advaced Spatio-Temporal Thermal Analysis of Electronic Systems

    Directory of Open Access Journals (Sweden)

    Miroslav Hrianka

    2003-01-01

    Full Text Available The article gives a brief review the of diagnostics and analysis possibilities by a spatio-temporal approach into electronic system in infrared bandwidth. The two dimensional image grabbed by the thermo vision camera provides information about the surface temperature distribution of an electronic system. The main idea is based on the analysis of the object which consists of a temporal sequence of a spatial thermal images. Advanced analysis is achieved by morphological image gradient spatio-temporal model: The mentioned method provides a total temperature system evaluation as well as it allows separate analysis in the chosen determined temperature area.

  3. Size-dependent diffusion promotes the emergence of spatiotemporal patterns

    DEFF Research Database (Denmark)

    Zhang, Lai; Thygesen, Uffe Høgsbro; Banerjee, Malay

    2014-01-01

    intraspecific physiological variations at the individual level. Here we explore the impacts of size variation within species resulting from individual ontogeny, on the emergence of spatiotemporal patterns in a fully size-structured population model. We found that size dependency of animal's diffusivity greatly...... populations. Due to the ubiquity of individual ontogeny in natural ecosystems we conclude that diffusion variability within populations is a significant driving force for the emergence of spatiotemporal patterns. Our results offer a perspective on self-organized phenomena, and pave a way to understand...

  4. Spatio-temporal data analytics for wind energy integration

    CERN Document Server

    Yang, Lei; Zhang, Junshan

    2014-01-01

    This SpringerBrief presents spatio-temporal data analytics for wind energy integration using stochastic modeling and optimization methods. It explores techniques for efficiently integrating renewable energy generation into bulk power grids. The operational challenges of wind, and its variability are carefully examined. A spatio-temporal analysis approach enables the authors to develop Markov-chain-based short-term forecasts of wind farm power generation. To deal with the wind ramp dynamics, a support vector machine enhanced Markov model is introduced. The stochastic optimization of economic di

  5. Time reversal and the spatio-temporal matched filter

    Energy Technology Data Exchange (ETDEWEB)

    Lehman, S K; Poggio, A J; Kallman, J S; Meyer, A W; Candy, J V

    2004-03-08

    It is known that focusing of an acoustic field by a time-reversal mirror (TRM) is equivalent to a spatio-temporal matched filter under conditions where the Green's function of the field satisfies reciprocity and is time invariant, i.e. the Green's function is independent of the choice of time origin. In this letter, it is shown that both reciprocity and time invariance can be replaced by a more general constraint on the Green's function that allows a TRM to implement the spatio-temporal matched filter even when conditions are time varying.

  6. Statistical analysis of spatial and spatio-temporal point patterns

    CERN Document Server

    Diggle, Peter J

    2013-01-01

    Written by a prominent statistician and author, the first edition of this bestseller broke new ground in the then emerging subject of spatial statistics with its coverage of spatial point patterns. Retaining all the material from the second edition and adding substantial new material, Statistical Analysis of Spatial and Spatio-Temporal Point Patterns, Third Edition presents models and statistical methods for analyzing spatially referenced point process data. Reflected in the title, this third edition now covers spatio-temporal point patterns. It explores the methodological developments from th

  7. Classification with spatio-temporal interpixel class dependency contexts

    Science.gov (United States)

    Jeon, Byeungwoo; Landgrebe, David A.

    1992-01-01

    A contextual classifier which can utilize both spatial and temporal interpixel dependency contexts is investigated. After spatial and temporal neighbors are defined, a general form of maximum a posterior spatiotemporal contextual classifier is derived. This contextual classifier is simplified under several assumptions. Joint prior probabilities of the classes of each pixel and its spatial neighbors are modeled by the Gibbs random field. The classification is performed in a recursive manner to allow a computationally efficient contextual classification. Experimental results with bitemporal TM data show significant improvement of classification accuracy over noncontextual pixelwise classifiers. This spatiotemporal contextual classifier should find use in many applications of remote sensing, especially when the classification accuracy is important.

  8. The Role of the Beetle Hypocryphalus mangiferae (Coleoptera: Curculionidae) in the Spatiotemporal Dynamics of Mango Wilt.

    Science.gov (United States)

    Galdino, Tarcísio Visintin da Silva; Ferreira, Dalton de Oliveira; Santana Júnior, Paulo Antônio; Arcanjo, Lucas de Paulo; Queiroz, Elenir Aparecida; Sarmento, Renato Almeida; Picanço, Marcelo Coutinho

    2017-06-01

    The knowledge of the spatiotemporal dynamics of pathogens and their vectors is an important step in determining the pathogen dispersion pattern and the role of vectors in disease dynamics. However, in the case of mango wilt little is known about its spatiotemporal dynamics and the relationship of its vector [the beetle Hypocryphalus mangiferae (Stebbing 1914)] to these dynamics. The aim of this work was to determine the spatial-seasonal dynamic of H. mangiferae attacks and mango wilt in mango orchards and to verify the importance of H. mangiferae in the spatiotemporal dynamics of the disease. Two mango orchards were monitored during a period of 3 yr. The plants in these orchards were georeferenced and inspected monthly to quantify the number of plants attacked by beetles and the fungus. In these orchards, the percentage of mango trees attacked by beetles was always higher than the percentage infected by the fungus. The colonization of mango trees by beetles and the fungus occurred by colonization of trees both distant and proximal to previously attacked trees. The new plants attacked by the fungus emerged in places where the beetles had previously begun their attack. This phenomenon led to a large overlap in sites of beetle and fungal occurrence, indicating that establishment by the beetle was followed by establishment by the fungus. This information can be used by farmers to predict disease infection, and to control bark beetle infestation in mango orchards. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Spatiotemporal characterization and mapping of PM2.5concentrations in southern Jiangsu Province, China.

    Science.gov (United States)

    Yang, Yong; Christakos, George; Yang, Xue; He, Junyu

    2018-03-01

    As a result of rapid industrialization and urbanization, China is experiencing severe air pollution problems. Understanding the spatiotemporal variation and trends of air pollution is a key element of an improved understanding of the underlying physical mechanisms and the implementation of the most effective risk assessment and environmental policy in the region. The motivation behind the present work is that the study region of southern Jiangsu province of China is one of the most populated and developed regions in China. The daily concentrations of particulate matter with particle diameter smaller than 2.5 μm (PM 2.5 ) in southern Jiangsu province obtained during the year 2014 were used to derive the variogram model that provided a quantitative characterization of the spatiotemporal (ST) variation of PM 2.5 concentrations in the study region. A spatiotemporal ordinary kriging (STOK) technique was subsequently employed to generate informative maps of the ST pollutant distribution in southern Jiangsu province. The results generated by STOK showed that during 2014 about 29.3% of the area was PM 2.5 polluted (at various severity levels, according to the criteria established by the Chinese government), and that the number of days characterized as polluted varied from 59 to 164 at different parts of the study region. Nanjing, the capital of Jiangsu province, was the place with the highest PM 2.5 pollution (including 3 days of serious pollution). The PM 2.5 pollution exhibited a decreasing spatial trend from the western to the eastern part of southern Jiangsu. A similar temporal PM 2.5 pattern was found from the western to the eastern part of southern Jiangsu, which was characterized by 4 peaks and 3 troughs linked to different meteorological conditions and human factors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Spatiotemporal Distribution of Chinavia hilaris (Hemiptera: Pentatomidae) in Peanut-Cotton Farmscapes.

    Science.gov (United States)

    Tillman, P Glynn; Cottrell, Ted E

    2015-01-01

    The green stink bug, Chinavia hilaris (Say) (Hemiptera: Pentatomidae), is a pest of cotton in the southeastern United States, but little is known concerning its spatiotemporal distribution in agricultural farmscapes. Therefore, spatiotemporal distribution of C. hilaris in farmscapes where cotton fields adjoined peanut was examined weekly. Spatial patterns of C. hilaris counts were analyzed using SADIE (Spatial Analysis by Distance Indices) methodology. Interpolated maps of C. hilaris density were used to visualize abundance and distribution of C. hilaris in crops. For the six peanut-cotton farmscapes studied, the frequency of C. hilaris in cotton (94.8%) was significantly higher than in peanut (5.2%), and nymphs were rarely detected in peanut, indicating that peanut was not a source of C. hilaris into cotton. Significantly, aggregated spatial distributions were detected in cotton. Maps of local clustering indices depicted patches of C. hilaris in cotton, mainly at field edges including the peanut-to-cotton interface. Black cherry (Prunus serotina Ehrh.) and elderberry (Sambucus nigra subsp. canadensis [L.] R. Bolli) grew in habitats adjacent to crops, C. hilaris were captured in pheromone-baited stink bug traps in these habitats, and in most instances, C. hilaris were observed feeding on black cherry and elderberry in these habitats before colonization of cotton. Spatial distribution of C. hilaris in these farmscapes revealed that C. hilaris colonized cotton field edges near these two noncrop hosts. Altogether, these findings suggest that black cherry and elderberry were sources of C. hilaris into cotton. Factors affecting the spatiotemporal dynamics of C. hilaris in peanut-cotton farmscapes are discussed. Published by Oxford University Press on behalf of the Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

  11. Spatio-temporal pattern of rainfall distribution over Ilorin metropolis ...

    African Journals Online (AJOL)

    Rainfall varies over time and space and the study of its variability cannot be over emphasized. This paper examines spatio-temporal patterns of rainfall in Ilorin metropolis, Nigeria. 30 years data were collected in 3 locations [Nigeria Meteorological Agency (NIMET), Lower Niger River Basin Development Authority (LNRBDA) ...

  12. Spatio-temporal variations in phytoplankton community structure in ...

    African Journals Online (AJOL)

    OMARI

    2013-09-06

    Sep 6, 2013 ... Spatio-temporal variations of phytoplankton, expressed in terms of species composition and diversity collected at various sampling sites in small water bodies (SWBs) within Lake Victoria basin, Kenya, were investigated monthly from November 2010 to June 2011, in relation to selected physical and.

  13. Spatio-temporal variations in phytoplankton community structure in ...

    African Journals Online (AJOL)

    OMARI

    2013-09-06

    Sep 6, 2013 ... Spatio-temporal variations of phytoplankton, expressed in terms of species composition and diversity collected at various sampling ... chemical and biological properties of water most often lead to the production of .... Persulfate digestion methods, respectively in the laboratory (APHA,. 2000). Data analysis.

  14. Spatiotemporal variability of marine renewable energy resources in Norway

    NARCIS (Netherlands)

    Varlas, George; Christakos, Konstantinos; Cheliotis, Ioannis; Papadopoulos, A.; Steeneveld, G.J.

    2017-01-01

    Marine Renewable Energy (MRE) resources such as wind and wave energy depend on the complex behaviour of weather and climatic conditions which determine the development of MRE technologies, energy grid, supply and prices. This study investigates the spatiotemporal variability of MRE resources along

  15. Spatiotemporal variability in carbon exchange fluxes across the Sahel

    DEFF Research Database (Denmark)

    Tagesson, Håkan Torbern; Fensholt, Rasmus; Cappelaere, Bernard

    2016-01-01

    Semi-arid regions play an increasingly important role as a sink within the global carbon (C) cycle and is the main biome driving inter-annual variability in carbon dioxide (CO2) uptake by terrestrial ecosystems. This indicates the need for detailed studies of spatiotemporal variability in C cycling...

  16. Scalable Top-k Spatio-Temporal Term Querying

    DEFF Research Database (Denmark)

    Skovsgaard, Anders; Sidlauskas, Darius; Jensen, Christian S.

    2014-01-01

    that are capable of providing the top-k terms seen in posts in a user-specified spatio-temporal range. The techniques enable interactive response times in the millisecond range in a realistic setting where the arrival rate of posts exceeds today's average tweet arrival rate by a factor of 4-10. The techniques...

  17. Elastic Cloud Computing Architecture and System for Heterogeneous Spatiotemporal Computing

    Science.gov (United States)

    Shi, X.

    2017-10-01

    Spatiotemporal computation implements a variety of different algorithms. When big data are involved, desktop computer or standalone application may not be able to complete the computation task due to limited memory and computing power. Now that a variety of hardware accelerators and computing platforms are available to improve the performance of geocomputation, different algorithms may have different behavior on different computing infrastructure and platforms. Some are perfect for implementation on a cluster of graphics processing units (GPUs), while GPUs may not be useful on certain kind of spatiotemporal computation. This is the same situation in utilizing a cluster of Intel's many-integrated-core (MIC) or Xeon Phi, as well as Hadoop or Spark platforms, to handle big spatiotemporal data. Furthermore, considering the energy efficiency requirement in general computation, Field Programmable Gate Array (FPGA) may be a better solution for better energy efficiency when the performance of computation could be similar or better than GPUs and MICs. It is expected that an elastic cloud computing architecture and system that integrates all of GPUs, MICs, and FPGAs could be developed and deployed to support spatiotemporal computing over heterogeneous data types and computational problems.

  18. Spatiotemporal soliton clusters in the (3+ 1)-dimensional nonlinear ...

    Indian Academy of Sciences (India)

    Logo of the Indian Academy of Sciences. Indian Academy of Sciences. Home · About ... Home; Journals; Pramana – Journal of Physics; Volume 89; Issue 3. Spatiotemporal soliton clusters in the ( 3 + ... HONG-YU WU1 LI-HONG JIANG1. College of Engineering and Design, Lishui University, Lishui 323000, Zhejiang, China ...

  19. Spatiotemporal radiotherapy planning using a global optimization approach.

    Science.gov (United States)

    Adibi, Ali; Salari, Ehsan

    2018-01-12

    This paper aims at quantifying the extent of potential therapeutic gain, measured using biologically effective dose (BED), that can be achieved by altering the radiation dose distribution over treatment sessions in fractionated radiotherapy. To that end, a spatiotemporally integrated planning approach is developed, where the spatial and temporal dose modulations are optimized simultaneously. The concept of equivalent uniform BED (EUBED) is used to quantify and compare the clinical quality of spatiotemporally heterogeneous dose distributions in target and critical structures. This gives rise to a large-scale non-convex treatment-plan optimization problem, which is solved using global optimization techniques. The proposed spatiotemporal planning approach is tested on two stylized cancer cases resembling two different tumor sites and sensitivity analysis is performed for radio-biological and EUBED parameters. Numerical results validate that spatiotemporal plans are capable of delivering a larger BED to the target volume without increasing the BED in critical structures compared to conventional time-invariant plans. In particular, this additional gain is attributed to the irradiation of different regions of the target volume at different treatment sessions. Additionally, the trade-off between the potential therapeutic gain and the number of distinct dose distributions is quantified, which suggests a diminishing marginal gain as the number of dose distributions increases. © 2018 Institute of Physics and Engineering in Medicine.

  20. Spatiotemporal response of crystals in x-ray Bragg diffraction

    Science.gov (United States)

    Shvyd'ko, Yuri; Lindberg, Ryan

    2012-10-01

    The spatiotemporal response of crystals in x-ray Bragg diffraction resulting from excitation by an ultrashort, laterally confined x-ray pulse is studied theoretically. The theory presents an extension of the analysis in symmetric reflection geometry [R. R. Lindberg and Y. V. Shvyd’ko, Phys. Rev. ST Accel. Beams 15, 050706 (2012)PRABFM1098-440210.1103/PhysRevSTAB.15.050706] to the generic case, which includes Bragg diffraction both in reflection (Bragg) and transmission (Laue) asymmetric scattering geometries. The spatiotemporal response is presented as a product of a crystal-intrinsic plane-wave spatiotemporal response function and an envelope function defined by the crystal-independent transverse profile of the incident beam and the scattering geometry. The diffracted wave fields exhibit amplitude modulation perpendicular to the propagation direction due to both angular dispersion and the dispersion due to Bragg’s law. The characteristic measure of the spatiotemporal response is expressed in terms of a few parameters: the extinction length, crystal thickness, Bragg angle, asymmetry angle, and the speed of light. Applications to self-seeding of hard x-ray free-electron lasers are discussed, with particular emphasis on the relative advantages of using either the Bragg or Laue scattering geometries. Intensity front inclination in asymmetric diffraction can be used to make snapshots of ultrafast processes with femtosecond resolution.

  1. Spatiotemporal response of crystals in x-ray Bragg diffraction

    Directory of Open Access Journals (Sweden)

    Yuri Shvyd’ko

    2012-10-01

    Full Text Available The spatiotemporal response of crystals in x-ray Bragg diffraction resulting from excitation by an ultrashort, laterally confined x-ray pulse is studied theoretically. The theory presents an extension of the analysis in symmetric reflection geometry [R. R. Lindberg and Y. V. Shvyd’ko, Phys. Rev. ST Accel. Beams 15, 050706 (2012PRABFM1098-440210.1103/PhysRevSTAB.15.050706] to the generic case, which includes Bragg diffraction both in reflection (Bragg and transmission (Laue asymmetric scattering geometries. The spatiotemporal response is presented as a product of a crystal-intrinsic plane-wave spatiotemporal response function and an envelope function defined by the crystal-independent transverse profile of the incident beam and the scattering geometry. The diffracted wave fields exhibit amplitude modulation perpendicular to the propagation direction due to both angular dispersion and the dispersion due to Bragg’s law. The characteristic measure of the spatiotemporal response is expressed in terms of a few parameters: the extinction length, crystal thickness, Bragg angle, asymmetry angle, and the speed of light. Applications to self-seeding of hard x-ray free-electron lasers are discussed, with particular emphasis on the relative advantages of using either the Bragg or Laue scattering geometries. Intensity front inclination in asymmetric diffraction can be used to make snapshots of ultrafast processes with femtosecond resolution.

  2. Visual experience modulates spatio-temporal dynamics of circuit activation

    Directory of Open Access Journals (Sweden)

    Lang eWang

    2011-06-01

    Full Text Available Persistent reduction in sensory drive in early development results in multiple plastic changes of different cortical synapses. How these experience-dependent modifications affect the spatio-temporal dynamics of signal propagation in neocortical circuits is poorly understood. Here we demonstrate that brief visual deprivation significantly affects the propagation of electrical signals in the primary visual cortex. The spatio-temporal spread of circuit activation upon direct stimulation of its input layer (Layer 4 is reduced, as is the activation of Layer 2/3 – the main recipient of the output from Layer 4. Our data suggest that the decrease in spatio-temporal activation of L2/3 depends on reduced L4 output, and is not intrinsically generated within L2/3. The data shown here suggest that changes in the synaptic components of the visual cortical circuit result not only in alteration of local integration of excitatory and inhibitory inputs, but also in a significant decrease in overall circuit activation. Furthermore, our data indicate a differential effect of visual deprivation on L4 and L2/3, suggesting that while feedforward activation of L2/3 is reduced, its activation by long range, within layer inputs is unaltered. Thus, brief visual deprivation induces experience-dependent circuit re-organization by modulating not only circuit excitability, but also the spatio-temporal patterns of cortical activation within and between layers.

  3. Online identification of nonlinear spatiotemporal systems using kernel learning approach.

    Science.gov (United States)

    Ning, Hanwen; Jing, Xingjian; Cheng, Li

    2011-09-01

    The identification of nonlinear spatiotemporal systems is of significance to engineering practice, since it can always provide useful insight into the underlying nonlinear mechanism and physical characteristics under study. In this paper, nonlinear spatiotemporal system models are transformed into a class of multi-input-multi-output (MIMO) partially linear systems (PLSs), and an effective online identification algorithm is therefore proposed by using a pruning error minimization principle and least square support vector machines. It is shown that many benchmark physical and engineering systems can be transformed into MIMO-PLSs which keep some important physical spatiotemporal relationships and are very helpful in the identification and analysis of the underlying system. Compared with several existing methods, the advantages of the proposed method are that it can make full use of some prior structural information about system physical models, can realize online estimation of the system dynamics, and achieve accurate characterization of some important nonlinear physical characteristics of the system. This would provide an important basis for state estimation, control, optimal analysis, and design of nonlinear distributed parameter systems. The proposed algorithm can also be applied to identification problems of stochastic spatiotemporal dynamical systems. Numeral examples and comparisons are given to demonstrate our results.

  4. Large scale stochastic spatio-temporal modelling with PCRaster

    NARCIS (Netherlands)

    Karssenberg, D.J.; Drost, N.; Schmitz, O.; Jong, K. de; Bierkens, M.F.P.

    2013-01-01

    PCRaster is a software framework for building spatio-temporal models of land surface processes (http://www.pcraster.eu). Building blocks of models are spatial operations on raster maps, including a large suite of operations for water and sediment routing. These operations are available to model

  5. Remote sensing monitoring the spatio-temporal changes of ...

    Indian Academy of Sciences (India)

    Xiaoming Cao

    2017-06-16

    Jun 16, 2017 ... the spatio-temporal variations of drought based on the temperature vegetation dryness index (TVDI). The results indicated that ... MODIS remote sensing data would be an effective method to monitor regional drought, moreover, it would be more ...... in high biomass ecosystems; Remote Sens. Environ. 115.

  6. Spatio-temporal analysis of Salmonella surveillance data in Thailand

    DEFF Research Database (Denmark)

    Coutinho Calado Domingues, Ana Rita; Vieira, Antonio; Hendriksen, Rene S.

    2014-01-01

    This study evaluates the usefulness of spatio-temporal statistical tools to detect outbreaks using routine surveillance data where limited epidemiological information is available. A dataset from 2002 to 2007 containing information regarding date, origin, source and serotype of 29 586 Salmonella...... that monitoring non-human reservoirs can be relevant in predicting future Salmonella human cases....

  7. Spatio-temporal distribution of the infestations of ...

    African Journals Online (AJOL)

    1 Entomology and soil fauna unity, UFR Biosciences, Cocody University, Abidjan (Côte d'Ivoire). 2 Pierre ... relative humidity). Larvae at stages 1, 2, 3 and 4 are mostly responsible of the damages observed in the fields. Key words: Coelaenomenodera lameensis; Elaeis guineensis; spatio-temporal distribution; Côte d'Ivoire.

  8. Spatiotemporal variations in microbial communities in a landfill leachate plume

    NARCIS (Netherlands)

    Brad, T.; Obergfell, C.; van Breukelen, B.M.; van Straalen, N.M.; Roling, W.F.M.

    2013-01-01

    We examined the spatiotemporal changes of microbial communities in relation to hydrochemistry variation over time and space in an aquifer polluted by landfill leachate (Banisveld, The Netherlands). Sampling in 1998, 1999, and 2004 at the same time of the year revealed that the center of the

  9. A dynamic spatio-temporal model for spatialdata

    Science.gov (United States)

    Hefley, Trevor J.; Hooten, Mevin B.; Hanks, Ephraim M.; Russell, Robin; Walsh, Daniel P.

    2017-01-01

    Analyzing spatial data often requires modeling dependencies created by a dynamic spatio-temporal data generating process. In many applications, a generalized linear mixed model (GLMM) is used with a random effect to account for spatial dependence and to provide optimal spatial predictions. Location-specific covariates are often included as fixed effects in a GLMM and may be collinear with the spatial random effect, which can negatively affect inference. We propose a dynamic approach to account for spatial dependence that incorporates scientific knowledge of the spatio-temporal data generating process. Our approach relies on a dynamic spatio-temporal model that explicitly incorporates location-specific covariates. We illustrate our approach with a spatially varying ecological diffusion model implemented using a computationally efficient homogenization technique. We apply our model to understand individual-level and location-specific risk factors associated with chronic wasting disease in white-tailed deer from Wisconsin, USA and estimate the location the disease was first introduced. We compare our approach to several existing methods that are commonly used in spatial statistics. Our spatio-temporal approach resulted in a higher predictive accuracy when compared to methods based on optimal spatial prediction, obviated confounding among the spatially indexed covariates and the spatial random effect, and provided additional information that will be important for containing disease outbreaks.

  10. An effective dissolve detector using spatio-temporal slice

    Science.gov (United States)

    Cai, Cheng; Lam, Kin-Man; Tan, Zheng

    2005-07-01

    The detection of edits in a video sequence is the first step in video analysis, which segments a video into its basic components. Spatio-temporal slice analysis is an effective method for video partitioning because it can detect and classify different scene breaks. In a spatio-temporal slice, cut and wipe can be detected successfully based on measuring the changes of the color-texture properties of the slices. Dissolve can be measured by means of the parabolic variance curve (PVC) method. However, the statistical information extracted from the horizontal, vertical, and diagonal slices is not enough to show the PVC features. Thus, Support Vector Machine (SVM)-based dissolve detector was proposed, which extracts features based on the Gabor wavelets from a spatio-temporal slice and then identifies dissolves by means of the SVM-based classifier. However, this method is computationally intensive. In our method, we propose an efficient dissolve detector based on the spatio-temporal slices by using three simple second-order filters. Based on the linear estimation of the successive frames in a video shot, dissolve and static scenes exhibit different patterns in the temporal dimension. By applying the three simple filters, we can identify dissolves with arbitrary lengths accurately. Experiments based on the MPEG-7 standard sequences show encouraging results.

  11. Spatio-temporal variations in phytoplankton community structure in ...

    African Journals Online (AJOL)

    Spatio-temporal variations of phytoplankton, expressed in terms of species composition and diversity collected at various sampling sites in small water bodies (SWBs) within Lake Victoria basin, Kenya, were investigated monthly from November 2010 to June 2011, in relation to selected physical and chemical water quality ...

  12. Spatio-Temporal Ensemble Prediction on Mobile Broadband Network Data

    DEFF Research Database (Denmark)

    Samulevicius, Saulius; Pitarch, Yoann; Pedersen, Torben Bach

    2013-01-01

    network nodes, fully or partly, in low traffic loads. To accomplish such a dynamic network optimization, it is crucial to predict very accurately low traffic periods. In this paper, we tackle this problem using data mining and propose Spatio-Temporal Ensemble Prediction (STEP). In a nutshell, STEP...

  13. Circuit Formation by Spatio-Temporal Control of Messenger RNA ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Circuit Formation by Spatio-Temporal Control of Messenger RNA Translation. The connections inside the brain need to be wired in a precise manner during development to ensure its proper function. This project will provide insight into circuit formation to help us understand how axon regeneration can improve clinical ...

  14. Using collective Metrics to inspect Spatio-Temporal relationships ...

    African Journals Online (AJOL)

    Using collective Metrics to inspect Spatio-Temporal relationships between football players. ... Four collective metrics (weighted Centroid, weighted Stretch Index, Surface Area and Effective Area of Play) were computed based on the location of the players at each second of a match. Three matches of a team were analysed ...

  15. Spatiotemporal variations in precipitation on the Huang-Huai-Hai ...

    Indian Academy of Sciences (India)

    47

    context of climate change. Based on daily precipitation data from 63 national meteorological stations on the Huang-Huai-Hai Plain from 1963 to 2012, this paper analyzed the spatiotemporal variations in precipitation in terms of precipitation days and intensity, using spatial interpolation, linear trend estimation and wavelet ...

  16. Implicit learning of spatiotemporal contingencies in spatial cueing.

    Science.gov (United States)

    Rieth, Cory A; Huber, David E

    2013-08-01

    We investigated the role of implicit spatiotemporal learning in the Posner spatial cueing of attention task. During initial training, the proportion of different trial types was altered to produce a complex pattern of spatiotemporal contingencies between cues and targets. For example, in the short invalid and long valid condition, targets reliably appeared either at an uncued location after a short stimulus onset asynchrony (SOA; 100 ms) or at a cued location after a long SOA (350 ms). As revealed by postexperiment questioning, most participants were unaware of these manipulations. Whereas prior studies have examined reaction times during training, the current study examined the long-term effect of training on subsequent testing that removed these contingencies. An initial experiment found training effects only for the long SOAs that typically produce inhibition of return (IOR) effects. For instance, after short invalid and long valid training, there was a benefit at long SOAs rather than an IOR effect. A 2nd experiment ruled out target-cue overlap as an explanation of the difference between learning for long versus short SOAs. Rather than a mix of perfectly predictable spatiotemporal contingencies, Experiment 3 used only short SOA trials during training with a probabilistic spatial contingency. There was a smaller but reliable training effect in subsequent testing. These results demonstrate that implicit learning for specific combinations of location and SOA can affect behavior in spatial cueing paradigms, which is a necessary result if more generally spatial cueing reflects learned spatiotemporal regularities. 2013 APA, all rights reserved

  17. Spatiotemporal Coupling of the Tongue in Amyotrophic Lateral Sclerosis

    Science.gov (United States)

    Kuruvilla, Mili S.; Green, Jordan R.; Yunusova, Yana; Hanford, Kathy

    2012-01-01

    Purpose: The primary aim of the investigation was to identify deficits in spatiotemporal coupling between tongue regions in amyotrophic lateral sclerosis (ALS). The relations between disease-related changes in tongue movement patterns and speech intelligibility were also determined. Methods: The authors recorded word productions from 11…

  18. GISpark: A Geospatial Distributed Computing Platform for Spatiotemporal Big Data

    Science.gov (United States)

    Wang, S.; Zhong, E.; Wang, E.; Zhong, Y.; Cai, W.; Li, S.; Gao, S.

    2016-12-01

    Geospatial data are growing exponentially because of the proliferation of cost effective and ubiquitous positioning technologies such as global remote-sensing satellites and location-based devices. Analyzing large amounts of geospatial data can provide great value for both industrial and scientific applications. Data- and compute- intensive characteristics inherent in geospatial big data increasingly pose great challenges to technologies of data storing, computing and analyzing. Such challenges require a scalable and efficient architecture that can store, query, analyze, and visualize large-scale spatiotemporal data. Therefore, we developed GISpark - a geospatial distributed computing platform for processing large-scale vector, raster and stream data. GISpark is constructed based on the latest virtualized computing infrastructures and distributed computing architecture. OpenStack and Docker are used to build multi-user hosting cloud computing infrastructure for GISpark. The virtual storage systems such as HDFS, Ceph, MongoDB are combined and adopted for spatiotemporal data storage management. Spark-based algorithm framework is developed for efficient parallel computing. Within this framework, SuperMap GIScript and various open-source GIS libraries can be integrated into GISpark. GISpark can also integrated with scientific computing environment (e.g., Anaconda), interactive computing web applications (e.g., Jupyter notebook), and machine learning tools (e.g., TensorFlow/Orange). The associated geospatial facilities of GISpark in conjunction with the scientific computing environment, exploratory spatial data analysis tools, temporal data management and analysis systems make up a powerful geospatial computing tool. GISpark not only provides spatiotemporal big data processing capacity in the geospatial field, but also provides spatiotemporal computational model and advanced geospatial visualization tools that deals with other domains related with spatial property. We

  19. Second-order analysis of structured inhomogeneous spatio-temporal point processes

    DEFF Research Database (Denmark)

    Møller, Jesper; Ghorbani, Mohammad

    Statistical methodology for spatio-temporal point processes is in its infancy. We consider second-order analysis based on pair correlation functions and K-functions for first general inhomogeneous spatio-temporal point processes and second inhomogeneous spatio-temporal Cox processes. Assuming......-temporal Gaussian process. Another concerns shot-noise Cox processes with a separable spatio-temporal covariance density. We propose diagnostic procedures for checking hypotheses of second-order spatio-temporal separability, which we apply on simulated and real data (the UK 2001 epidemic foot and mouth disease data)....

  20. Recent results on the spatiotemporal modelling and comparative analysis of Black Death and bubonic plague epidemics

    Science.gov (United States)

    Christakos, G.; Olea, R.A.; Yu, H.-L.

    2007-01-01

    Background: This work demonstrates the importance of spatiotemporal stochastic modelling in constructing maps of major epidemics from fragmentary information, assessing population impacts, searching for possible etiologies, and performing comparative analysis of epidemics. Methods: Based on the theory previously published by the authors and incorporating new knowledge bases, informative maps of the composite space-time distributions were generated for important characteristics of two major epidemics: Black Death (14th century Western Europe) and bubonic plague (19th-20th century Indian subcontinent). Results: The comparative spatiotemporal analysis of the epidemics led to a number of interesting findings: (1) the two epidemics exhibited certain differences in their spatiotemporal characteristics (correlation structures, trends, occurrence patterns and propagation speeds) that need to be explained by means of an interdisciplinary effort; (2) geographical epidemic indicators confirmed in a rigorous quantitative manner the partial findings of isolated reports and time series that Black Death mortality was two orders of magnitude higher than that of bubonic plague; (3) modern bubonic plague is a rural disease hitting harder the small villages in the countryside whereas Black Death was a devastating epidemic that indiscriminately attacked large urban centres and the countryside, and while the epidemic in India lasted uninterruptedly for five decades, in Western Europe it lasted three and a half years; (4) the epidemics had reverse areal extension features in response to annual seasonal variations. Temperature increase at the end of winter led to an expansion of infected geographical area for Black Death and a reduction for bubonic plague, reaching a climax at the end of spring when the infected area in Western Europe was always larger than in India. Conversely, without exception, the infected area during winter was larger for the Indian bubonic plague; (5) during the

  1. Recent results on the spatiotemporal modelling and comparative analysis of Black Death and bubonic plague epidemics.

    Science.gov (United States)

    Christakos, G; Olea, R A; Yu, H-L

    2007-09-01

    This work demonstrates the importance of spatiotemporal stochastic modelling in constructing maps of major epidemics from fragmentary information, assessing population impacts, searching for possible etiologies, and performing comparative analysis of epidemics. Based on the theory previously published by the authors and incorporating new knowledge bases, informative maps of the composite space-time distributions were generated for important characteristics of two major epidemics: Black Death (14th century Western Europe) and bubonic plague (19th-20th century Indian subcontinent). The comparative spatiotemporal analysis of the epidemics led to a number of interesting findings: (1) the two epidemics exhibited certain differences in their spatiotemporal characteristics (correlation structures, trends, occurrence patterns and propagation speeds) that need to be explained by means of an interdisciplinary effort; (2) geographical epidemic indicators confirmed in a rigorous quantitative manner the partial findings of isolated reports and time series that Black Death mortality was two orders of magnitude higher than that of bubonic plague; (3) modern bubonic plague is a rural disease hitting harder the small villages in the countryside whereas Black Death was a devastating epidemic that indiscriminately attacked large urban centres and the countryside, and while the epidemic in India lasted uninterruptedly for five decades, in Western Europe it lasted three and a half years; (4) the epidemics had reverse areal extension features in response to annual seasonal variations. Temperature increase at the end of winter led to an expansion of infected geographical area for Black Death and a reduction for bubonic plague, reaching a climax at the end of spring when the infected area in Western Europe was always larger than in India. Conversely, without exception, the infected area during winter was larger for the Indian bubonic plague; (5) during the Indian epidemic, the disease

  2. Spatiotemporal Effects of Climate Variability and Urban Growth on the "Valle de Toluca" Aquifer (Mexico)

    Science.gov (United States)

    Mastachi-Loza, C. A.; Diaz-Delgado, C.; Esteller, M. V.; Gomez-Albores, M. A.; Becerril, R.; Ruiz-Gomez, M. D.

    2013-05-01

    Toluca city is located in the "Valle de Toluca" at the upper course of the Lerma river basin, is an important economic center which contributes with 1.2% of Gross National Product (GNP) since it is an industrial city, The city has grown due to the economic development sustained by the "Valle de Toluca" aquifer which provides water for human consumption, industrial facilities and crop irrigation. Recent studies have shown that in the last 50 years the annual precipitation rate in Toluca has increased 122 mm, whereas the daily minimum temperature has increased 1.1 °C and the daily maximum temperature has also increased 0.8 °C. These results show a general overview of the change in the climate conditions of the city; however they do not show the spatial distribution of the change. For this reason, the aim of this work was to evaluate the spatiotemporal change of precipitation rates and urban growth in order to determine their effects over the "Valle de Toluca" aquifer. In order to detect the urban growth, a supervised classification technique has been used taking into account Landsat TM satellite images between 1973, 1986, 2000 and 2005. A yearly spatiotemporal raster set of rainfall rates from 1980 to 2010 were obtained interpolating data from 812 climatologic stations. To evaluate the effect in annual precipitation rates and urban growth over the aquifer, we interpolate data from 38 piezometers from 1980 to 2010 to obtain a spatiotemporal raster set. The piezometric values correspond to the aquifer's upper level. The spatiotemporal raster sets were analyzed with the non-parametric Theil-Sen test to determine trends in piezometric levels and precipitation rates. Finally the urban growth, spatial-temporal trends of precipitation rates and piezometric levels were displayed in a GIS and then subjectively analyzed to figure out coincidences. An increase in annual precipitation rates (+87 mm) over Toluca's Valley during the last three decades was observed specially

  3. Interesting Spatio-Temporal Region Discovery Computations Over Gpu and Mapreduce Platforms

    Science.gov (United States)

    McDermott, M.; Prasad, S. K.; Shekhar, S.; Zhou, X.

    2015-07-01

    Discovery of interesting paths and regions in spatio-temporal data sets is important to many fields such as the earth and atmospheric sciences, GIS, public safety and public health both as a goal and as a preliminary step in a larger series of computations. This discovery is usually an exhaustive procedure that quickly becomes extremely time consuming to perform using traditional paradigms and hardware and given the rapidly growing sizes of today's data sets is quickly outpacing the speed at which computational capacity is growing. In our previous work (Prasad et al., 2013a) we achieved a 50 times speedup over sequential using a single GPU. We were able to achieve near linear speedup over this result on interesting path discovery by using Apache Hadoop to distribute the workload across multiple GPU nodes. Leveraging the parallel architecture of GPUs we were able to drastically reduce the computation time of a 3-dimensional spatio-temporal interest region search on a single tile of normalized difference vegetative index for Saudi Arabia. We were further able to see an almost linear speedup in compute performance by distributing this workload across several GPUs with a simple MapReduce model. This increases the speed of processing 10 fold over the comparable sequential while simultaneously increasing the amount of data being processed by 384 fold. This allowed us to process the entirety of the selected data set instead of a constrained window.

  4. Spatio-Temporal Feature Exploration in Combined Particle/Volume Reference Frames.

    Science.gov (United States)

    Sauer, Franz; Ma, Kwan-Liu

    2017-06-01

    The use of large-scale scientific simulations that can represent physical systems using both particle and volume data simultaneously is gaining popularity as each of these reference frames has an inherent set of advantages when studying different phenomena. Furthermore, being able to study the dynamic evolution of these time varying data types is an integral part of nearly all scientific endeavors. However, the techniques available to scientists generally limit them to studying each reference frame separately making it difficult to draw connections between the two. In this work we present a novel method of feature exploration that can be used to investigate spatio-temporal patterns in both data types simultaneously. More specifically, we focus on how spatio-temporal subsets can be identified from both reference frames, and develop new ways of visually presenting the embedded information to a user in an intuitive manner. We demonstrate the effectiveness of our method using case studies of real world scientific datasets and illustrate the new types of exploration and analyses that can be achieved through this technique.

  5. Neural avalanches at the critical point between replay and non-replay of spatiotemporal patterns.

    Directory of Open Access Journals (Sweden)

    Silvia Scarpetta

    Full Text Available We model spontaneous cortical activity with a network of coupled spiking units, in which multiple spatio-temporal patterns are stored as dynamical attractors. We introduce an order parameter, which measures the overlap (similarity between the activity of the network and the stored patterns. We find that, depending on the excitability of the network, different working regimes are possible. For high excitability, the dynamical attractors are stable, and a collective activity that replays one of the stored patterns emerges spontaneously, while for low excitability, no replay is induced. Between these two regimes, there is a critical region in which the dynamical attractors are unstable, and intermittent short replays are induced by noise. At the critical spiking threshold, the order parameter goes from zero to one, and its fluctuations are maximized, as expected for a phase transition (and as observed in recent experimental results in the brain. Notably, in this critical region, the avalanche size and duration distributions follow power laws. Critical exponents are consistent with a scaling relationship observed recently in neural avalanches measurements. In conclusion, our simple model suggests that avalanche power laws in cortical spontaneous activity may be the effect of a network at the critical point between the replay and non-replay of spatio-temporal patterns.

  6. Spatiotemporal analysis of vehicle collisions involving wild boar and roe deer in NW Spain.

    Science.gov (United States)

    Rodríguez-Morales, Beatriz; Díaz-Varela, Emilio Rafael; Marey-Pérez, Manuel Francisco

    2013-11-01

    Ungulate-vehicle collisions pose a serious traffic safety hazard in the North of Spain. The understanding of underlying temporal and spatial structure of these non-random events is imperative to develop appropriate mitigation measures. This study analyses the temporal, spatial and spatiotemporal patterns of car crashes involving wild boar and roe deer in the province of Lugo (NW Spain) in the period 2006-2010 using geographic information systems (GIS) and spatial statistics. The temporal analysis--conducted at three scales: daily, weekly and seasonal--revealed that accidents are related to specific animal's life cycles and to interactions with human activities. The localization of collision points with GIS discovered the sections of the autonomic road network where accidents with the two studied species concentrate. Besides, the spatial arrangement of significant hotspots was mapped through kernel density estimation over two time scales (daily and seasonal), distinguishing among 41 sets, sequentially arranged to facilitate clustering comparison and determination of spatiotemporal risky areas. This work is of valuable help for road managers to design the appropriate mitigation measures that will improve traffic safety and animal welfare. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Spatiotemporal Co-existence of Female Thyroid and Breast Cancers in Hangzhou, China

    Science.gov (United States)

    Fei, Xufeng; Christakos, George; Lou, Zhaohan; Ren, Yanjun; Liu, Qingmin; Wu, Jiaping

    2016-06-01

    Thyroid and breast cancers (TC, BC) are common female malignant tumors worldwide. Studies suggest that TC patients have a higher BC risk, and vice versa. However, it has not been investigated quantitatively if there is an association between the space-time TC and BC incidence distributions at the population level. This work aims to answer this question. 5358 TC and 8784 BC (female) cases were diagnosed in Hangzhou (China, 2008-2012). Pearson and Spearman rank correlation coefficients of the TC and BC incidences were high, and their patterns were geographically similar. The spatiotemporal co-existence of TC and BC distributions was investigated using the integrative disease predictability (IDP) criterion: if TC-BC association is part of the disease mapping knowledge bases, it should yield improved space-time incidence predictions. Improved TC (BC) incidence predictions were generated when integrating both TC and BC data than when using only TC (BC) data. IDP consistently demonstrated the spatiotemporal co-existence of TC and BC distributions throughout Hangzhou (2008-2012), which means that when the population experiences high incidences of one kind of cancer attention should be paid to the other kind of cancer too. The strength of TC-BC association was measured by the IDP coefficients and incidence prediction accuracy.

  8. Spatiotemporal analysis of the appearance of gamma-band Microstates in resting state MEG.

    Science.gov (United States)

    Kelsey, Matthew; Prior, Fred W; Larson-Prior, Linda J

    2015-01-01

    Spatiotemporal analysis of EEG signal has revealed a rich set of methods to quantify neuronal activity using spatially global topographic templates, called Microstates. These methods complement more traditional spectral analysis, which uses band limited source data to determine defining differences in band power and peak characteristics. The high sampling rate and increased resistance to high frequency noise of MEG data offers an opportunity to explore the utility of spatiotemporal analysis over a wider spectrum than in EEG. In this work, we explore the utility of representing band limited MEG source data using established microstate techniques, especially in gamma frequency bands - a range yet unexplored using these techniques. We develop methods for gauging the goodness-of-fit achieved by resultant microstate templates and demonstrate sensor-level dispersion characteristics across wide-band signals as well as across signals filtered by canonical bands. These analyses reveal that, while high-frequency-band derived microstate templates are visually lawful, they fail to exhibit important explained variance and dispersion characteristics present in low- and full-band data necessary to meet the requirements of a microstate model.

  9. Spatio-Temporal Variations and Source Apportionment of Water Pollution in Danjiangkou Reservoir Basin, Central China

    Directory of Open Access Journals (Sweden)

    Pan Chen

    2015-05-01

    Full Text Available Understanding the spatio-temporal variation and the potential source of water pollution could greatly improve our knowledge of human impacts on the environment. In this work, data of 11 water quality indices were collected during 2012–2014 at 10 monitoring sites in the mainstream and major tributaries of the Danjiangkou Reservoir Basin, Central China. The fuzzy comprehensive assessment (FCA, the cluster analysis (CA and the discriminant analysis (DA were used to assess the water pollution status and analyze its spatio-temporal variation. Ten sites were classified by the high pollution (HP region and the low pollution (LP region, while 12 months were divided into the wet season and the dry season. It was found that the HP region was mainly in the small tributaries with small drainage areas and low average annual discharges, and it was also found that most of these rivers went through urban areas with industrial and domestic sewages input into the water body. Principal component analysis/factor analysis (PCA/FA was applied to reveal potential pollution sources, whereas absolute principal component score-multiple linear regression (APCS-MLR was used to identify their contributions to each water quality variable. The study area was found as being generally affected by industrial and domestic sewage. Furthermore, the HP region was polluted by chemical industries, and the LP region was influenced by agricultural and livestock sewage.

  10. Low-dose 4D cone-beam CT via joint spatiotemporal regularization of tensor framelet and nonlocal total variation

    Science.gov (United States)

    Han, Hao; Gao, Hao; Xing, Lei

    2017-08-01

    Excessive radiation exposure is still a major concern in 4D cone-beam computed tomography (4D-CBCT) due to its prolonged scanning duration. Radiation dose can be effectively reduced by either under-sampling the x-ray projections or reducing the x-ray flux. However, 4D-CBCT reconstruction under such low-dose protocols is prone to image artifacts and noise. In this work, we propose a novel joint regularization-based iterative reconstruction method for low-dose 4D-CBCT. To tackle the under-sampling problem, we employ spatiotemporal tensor framelet (STF) regularization to take advantage of the spatiotemporal coherence of the patient anatomy in 4D images. To simultaneously suppress the image noise caused by photon starvation, we also incorporate spatiotemporal nonlocal total variation (SNTV) regularization to make use of the nonlocal self-recursiveness of anatomical structures in the spatial and temporal domains. Under the joint STF-SNTV regularization, the proposed iterative reconstruction approach is evaluated first using two digital phantoms and then using physical experiment data in the low-dose context of both under-sampled and noisy projections. Compared with existing approaches via either STF or SNTV regularization alone, the presented hybrid approach achieves improved image quality, and is particularly effective for the reconstruction of low-dose 4D-CBCT data that are not only sparse but noisy.

  11. Uncertainty assessment of PM2.5 contamination mapping using spatiotemporal sequential indicator simulations and multi-temporal monitoring data.

    Science.gov (United States)

    Yang, Yong; Christakos, George; Huang, Wei; Lin, Chengda; Fu, Peihong; Mei, Yang

    2016-04-12

    Because of the rapid economic growth in China, many regions are subjected to severe particulate matter pollution. Thus, improving the methods of determining the spatiotemporal distribution and uncertainty of air pollution can provide considerable benefits when developing risk assessments and environmental policies. The uncertainty assessment methods currently in use include the sequential indicator simulation (SIS) and indicator kriging techniques. However, these methods cannot be employed to assess multi-temporal data. In this work, a spatiotemporal sequential indicator simulation (STSIS) based on a non-separable spatiotemporal semivariogram model was used to assimilate multi-temporal data in the mapping and uncertainty assessment of PM2.5 distributions in a contaminated atmosphere. PM2.5 concentrations recorded throughout 2014 in Shandong Province, China were used as the experimental dataset. Based on the number of STSIS procedures, we assessed various types of mapping uncertainties, including single-location uncertainties over one day and multiple days and multi-location uncertainties over one day and multiple days. A comparison of the STSIS technique with the SIS technique indicate that a better performance was obtained with the STSIS method.

  12. World Spatiotemporal Analytics and Mapping Project (WSTAMP): Discovering, Exploring, and Mapping Spatiotemporal Patterns across the World s Largest Open Source Geographic Data Sets

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Robert N [ORNL; Piburn, Jesse O [ORNL; Sorokine, Alexandre [ORNL; Myers, Aaron T [ORNL; White, Devin A [ORNL

    2015-01-01

    The application of spatiotemporal (ST) analytics to integrated data from major sources such as the World Bank, United Nations, and dozens of others holds tremendous potential for shedding new light on the evolution of cultural, health, economic, and geopolitical landscapes on a global level. Realizing this potential first requires an ST data model that addresses challenges in properly merging data from multiple authors, with evolving ontological perspectives, semantical differences, and changing attributes, as well as content that is textual, numeric, categorical, and hierarchical. Equally challenging is the development of analytical and visualization approaches that provide a serious exploration of this integrated data while remaining accessible to practitioners with varied backgrounds. The WSTAMP project at Oak Ridge National Laboratory has yielded two major results in addressing these challenges: 1) development of the WSTAMP database, a significant advance in ST data modeling that integrates 10,000+ attributes covering over 200 nation states spanning over 50 years from over 30 major sources and 2) a novel online ST exploratory and analysis tool providing an array of modern statistical and visualization techniques for analyzing these data temporally, spatially, and spatiotemporally under a standard analytic workflow. We discuss the status of this work and report on major findings. Acknowledgment Prepared by Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6285, managed by UT-Battelle, LLC for the U. S. Department of Energy under contract no. DEAC05-00OR22725. Copyright This manuscript has been authored by employees of UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the U.S. Department of Energy. Accordingly, the United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or

  13. Spatio-Temporal Analysis of Water Quality Parameters in Machángara River with Nonuniform Interpolation Methods

    Directory of Open Access Journals (Sweden)

    Iván P. Vizcaíno

    2016-11-01

    Full Text Available Water quality measurements in rivers are usually performed at intervals of days or months in monitoring campaigns, but little attention has been paid to the spatial and temporal dynamics of those measurements. In this work, we propose scrutinizing the scope and limitations of state-of-the-art interpolation methods aiming to estimate the spatio-temporal dynamics (in terms of trends and structures of relevant variables for water quality analysis usually taken in rivers. We used a database with several water quality measurements from the Machángara River between 2002 and 2007 provided by the Metropolitan Water Company of Quito, Ecuador. This database included flow rate, temperature, dissolved oxygen, and chemical oxygen demand, among other variables. For visualization purposes, the absence of measurements at intermediate points in an irregular spatio-temporal sampling grid was fixed by using deterministic and stochastic interpolation methods, namely, Delaunay and k-Nearest Neighbors (kNN. For data-driven model diagnosis, a study on model residuals was performed comparing the quality of both kinds of approaches. For most variables, a value of k = 15 yielded a reasonable fitting when Mahalanobis distance was used, and water quality variables were better estimated when using the kNN method. The use of kNN provided the best estimation capabilities in the presence of atypical samples in the spatio-temporal dynamics in terms of leave-one-out absolute error, and it was better for variables with slow-changing dynamics, though its performance degraded for variables with fast-changing dynamics. The proposed spatio-temporal analysis of water quality measurements provides relevant and useful information, hence complementing and extending the classical statistical analysis in this field, and our results encourage the search for new methods overcoming the limitations of the analyzed traditional interpolators.

  14. Acoustic goniometry: a spatio-temporal approach

    OpenAIRE

    Van Lancker, Eric; Rossi, Mario

    2005-01-01

    This work was motivated by the increasing need for acoustic localization systems. The various localization systems that were implemented during this PhD include localization of snow avalanches, artillery and supersonic aircraft in the infrasound domain, the localization of helicopters, civilian aircraft, speakers and auditorium reflections in the audio domain and the localization of chirps in the underwater ultrasound domain. The "goniometer" is defined as an instrument that measures angles. ...

  15. Nonlinear Spatio-Temporal Dynamics and Chaos in Semiconductors

    Science.gov (United States)

    Schöll, Eckehard

    2005-08-01

    Nonlinear transport phenomena are an increasingly important aspect of modern semiconductor research. This volume deals with complex nonlinear dynamics, pattern formation, and chaotic behavior in such systems. It bridges the gap between two well-established fields: the theory of dynamic systems and nonlinear charge transport in semiconductors. This unified approach helps reveal important electronic transport instabilities. The initial chapters lay a general framework for the theoretical description of nonlinear self-organized spatio-temporal patterns, such as current filaments, field domains, fronts, and analysis of their stability. Later chapters consider important model systems in detail: impact ionization induced impurity breakdown, Hall instabilities, superlattices, and low-dimensional structures. State-of-the-art results include chaos control, spatio-temporal chaos, multistability, pattern selection, activator-inhibitor kinetics, and global coupling, linking fundamental issues to electronic device applications. This book will be of great value to semiconductor physicists and nonlinear scientists alike.

  16. Pain Recognition using Spatiotemporal Oriented Energy of Facial Muscles

    DEFF Research Database (Denmark)

    Irani, Ramin; Nasrollahi, Kamal; Moeslund, Thomas B.

    2015-01-01

    Pain is a critical sign in many medical situations and its automatic detection and recognition using computer vision techniques is of great importance. Utilizes this fact that pain is a spatiotemporal process, the proposed system in this paper employs steerable and separable filters to measures e...... energies released by the facial muscles during the pain process. The proposed system not only detects the pain but recognizes its level. Experimental results on the publicly available pain database of UNBC show promising outcome for automatic pain detection and recognition.......Pain is a critical sign in many medical situations and its automatic detection and recognition using computer vision techniques is of great importance. Utilizes this fact that pain is a spatiotemporal process, the proposed system in this paper employs steerable and separable filters to measures...

  17. Annual spatiotemporal migration schedules in three larger insectivorous birds

    DEFF Research Database (Denmark)

    Jacobsen, Lars Bo; Jensen, Niels Odder; Willemoes, Mikkel

    2017-01-01

    Background: Knowledge of spatiotemporal migration patterns is important for our understanding of migration ecology and ultimately conservation of migratory species. We studied the annual migration schedules of European nightjar, a large nocturnal insectivore and compared it with two other larger...... the annual migrations of nightjars and swifts and compared these with satellite tracking of cuckoo migration. Results: Individuals of the three species migrated to wintering grounds centered in Central Africa, except some common swifts that remained in West Africa, crossing or circumventing the Sahara along...... different routes in spring and fall. Overall, all species showed similar regional and seasonal use of several stopover areas during migration. Among the three species, European nightjars and common cuckoos showed the most similar spatiotemporal migration patterns. The nightjars wintered in SW Central Africa...

  18. Spatiotemporal Scaling Effect on Rainfall Network Design Using Entropy

    Directory of Open Access Journals (Sweden)

    Chiang Wei

    2014-08-01

    Full Text Available Because of high variation in mountainous areas, rainfall data at different spatiotemporal scales may yield potential uncertainty for network design. However, few studies focus on the scaling effect on both the spatial and the temporal scale. By calculating the maximum joint entropy of hourly typhoon events, monthly, six dry and wet months and annual rainfall between 1992 and 2012 for 1-, 3-, and 5-km grids, the relocated candidate rain gauges in the National Taiwan University Experimental Forest of Central Taiwan are prioritized. The results show: (1 the network exhibits different locations for first prioritized candidate rain gauges for different spatiotemporal scales; (2 the effect of spatial scales is insignificant compared to temporal scales; and (3 a smaller number and a lower percentage of required stations (PRS reach stable joint entropy for a long duration at finer spatial scale. Prioritized candidate rain gauges provide key reference points for adjusting the network to capture more accurate information and minimize redundancy.

  19. The effects of spatiotemporal coherence on interferometric imaging

    CERN Document Server

    Shin, Seungwoo; Lee, KyeoReh; Lee, SangYun; Park, YongKeun

    2016-01-01

    Illumination coherence plays a major role in various imaging systems, from microscopy, metrology, digital holography, optical coherence tomography, to ultrasound imaging. Here, we present a systematic study on the effects of degrees of spatiotemporal coherence of an illumination (DSTCI) on imaging quality. An optical field with arbitrary DSTCI was decomposed into wavelets with constituent spatiotemporal frequencies, and the effects on image quality were quantitatively investigated. The results show the synergistic effects on reduction of speckle noise when DSTCI is decreased. This study presents a method to systematically control DSTCI, and the result provides an essential reference on the effects of DSTCI on imaging quality. We believe that the presented methods and results can be implemented in various imaging systems for characterising and improving imaging quality.

  20. A Framework for Discovering Evolving Domain Related Spatio-Temporal Patterns in Twitter

    Directory of Open Access Journals (Sweden)

    Yan Shi

    2016-10-01

    Full Text Available In massive Twitter datasets, tweets deriving from different domains, e.g., civil unrest, can be extracted to constitute spatio-temporal Twitter events for spatio-temporal distribution pattern detection. Existing algorithms generally employ scan statistics to detect spatio-temporal hotspots from Twitter events and do not consider the spatio-temporal evolving process of Twitter events. In this paper, a framework is proposed to discover evolving domain related spatio-temporal patterns from Twitter data. Given a target domain, a dynamic query expansion is employed to extract related tweets to form spatio-temporal Twitter events. The new spatial clustering approach proposed here is based on the use of multi-level constrained Delaunay triangulation to capture the spatial distribution patterns of Twitter events. An additional spatio-temporal clustering process is then performed to reveal spatio-temporal clusters and outliers that are evolving into spatial distribution patterns. Extensive experiments on Twitter datasets related to an outbreak of civil unrest in Mexico demonstrate the effectiveness and practicability of the new method. The proposed method will be helpful to accurately predict the spatio-temporal evolution process of Twitter events, which belongs to a deeper geographical analysis of spatio-temporal Big Data.

  1. The spatio-temporal dynamics of neutral genetic diversity

    OpenAIRE

    Bonnefon, Olivier; Coville, Jérôme; Garnier, Jimmy; Hamel, François; Roques, Lionel

    2014-01-01

    International audience; The notions of pulled and pushed solutions of reaction-dispersal equations introduced by Garnier et al. (2012) and Roques et al. (2012) are based on a decomposition of the solutions into several components. In the framework of population dynamics, this decomposition is related to the spatio-temporal evolution of the genetic structure of a population. The pulled solutions describe a rapid erosion of neutral genetic diversity, while the pushed solutions are associated wi...

  2. Characteristics and Applications of Spatiotemporally Focused Femtosecond Laser Pulses

    Directory of Open Access Journals (Sweden)

    Chenrui Jing

    2016-12-01

    Full Text Available Simultaneous spatial and temporal focusing (SSTF of femtosecond laser pulses gives rise to strong suppression of nonlinear self-focusing during the propagation of the femtosecond laser beam. In this paper, we begin with an introduction of the principle of SSTF, followed by a review of our recent experimental results on the characterization and application of the spatiotemporally focused pulses for femtosecond laser micromachining. Finally, we summarize all of the results and give a future perspective of this technique.

  3. Spatiotemporal causal modeling for the management of Dengue Fever

    Science.gov (United States)

    Yu, Hwa-Lung; Huang, Tailin; Lee, Chieh-Han

    2015-04-01

    Increasing climatic extremes have caused growing concerns about the health effects and disease outbreaks. The association between climate variation and the occurrence of epidemic diseases play an important role on a country's public health systems. Part of the impacts are direct casualties associated with the increasing frequency and intensity of typhoons, the proliferation of disease vectors and the short-term increase of clinic visits on gastro-intestinal discomforts, diarrhea, dermatosis, or psychological trauma. Other impacts come indirectly from the influence of disasters on the ecological and socio-economic systems, including the changes of air/water quality, living environment and employment condition. Previous risk assessment studies on dengue fever focus mostly on climatic and non-climatic factors and their association with vectors' reproducing pattern. The public-health implication may appear simple. Considering the seasonal changes and regional differences, however, the causality of the impacts is full of uncertainties. Without further investigation, the underlying dengue fever risk dynamics may not be assessed accurately. The objective of this study is to develop an epistemic framework for assessing dynamic dengue fever risk across space and time. The proposed framework integrates cross-departmental data, including public-health databases, precipitation data over time and various socio-economic data. We explore public-health issues induced by typhoon through literature review and spatiotemporal analytic techniques on public health databases. From those data, we identify relevant variables and possible causal relationships, and their spatiotemporal patterns derived from our proposed spatiotemporal techniques. Eventually, we create a spatiotemporal causal network and a framework for modeling dynamic dengue fever risk.

  4. Forecasting intentional wildfires using temporal and spatiotemporal autocorrelations

    Science.gov (United States)

    Jeffrey P. Prestemon; María L. Chas-Amil; Julia M. Touza; Scott L. Goodrick

    2012-01-01

    We report daily time series models containing both temporal and spatiotemporal lags, which are applied to forecasting intentional wildfires in Galicia, Spain. Models are estimated independently for each of the 19 forest districts in Galicia using a 1999–2003 training dataset and evaluated out-of-sample with a 2004–06 dataset. Poisson autoregressive models of order P –...

  5. A Spatio-Temporal Analysis of Mitochondrial DNA Haplogroup I

    Directory of Open Access Journals (Sweden)

    Revesz Peter Z.

    2016-01-01

    Full Text Available The recent recovery of ancient DNA from a growing number of human samples shows that mitochondrial DNA haplogroup I was introduced to Europe after the end of the Last Glacial Maximum. This paper provides a spatio-temporal analysis of the various subhaplogroups of mitochondrial DNA I. The study suggests that haplogroup I diversified into haplogroups I1, I2’3, I4 and I5 at specific regions in Eurasia and then spread southward to Crete and Egypt.

  6. Mapping Global Atmospheric CO2 Concentration at High Spatiotemporal Resolution

    Directory of Open Access Journals (Sweden)

    Yingying Jing

    2014-11-01

    Full Text Available Satellite measurements of the spatiotemporal distributions of atmospheric CO2 concentrations are a key component for better understanding global carbon cycle characteristics. Currently, several satellite instruments such as the Greenhouse gases Observing SATellite (GOSAT, SCanning Imaging Absorption Spectrometer for Atmospheric CHartographY (SCIAMACHY, and Orbiting Carbon Observatory-2 can be used to measure CO2 column-averaged dry air mole fractions. However, because of cloud effects, a single satellite can only provide limited CO2 data, resulting in significant uncertainty in the characterization of the spatiotemporal distribution of atmospheric CO2 concentrations. In this study, a new physical data fusion technique is proposed to combine the GOSAT and SCIAMACHY measurements. On the basis of the fused dataset, a gap-filling method developed by modeling the spatial correlation structures of CO2 concentrations is presented with the goal of generating global land CO2 distribution maps with high spatiotemporal resolution. The results show that, compared with the single satellite dataset (i.e., GOSAT or SCIAMACHY, the global spatial coverage of the fused dataset is significantly increased (reaching up to approximately 20%, and the temporal resolution is improved by two or three times. The spatial coverage and monthly variations of the generated global CO2 distributions are also investigated. Comparisons with ground-based Total Carbon Column Observing Network (TCCON measurements reveal that CO2 distributions based on the gap-filling method show good agreement with TCCON records despite some biases. These results demonstrate that the fused dataset as well as the gap-filling method are rather effective to generate global CO2 distribution with high accuracies and high spatiotemporal resolution.

  7. A Multiple Regression Approach to Normalization of Spatiotemporal Gait Features.

    Science.gov (United States)

    Wahid, Ferdous; Begg, Rezaul; Lythgo, Noel; Hass, Chris J; Halgamuge, Saman; Ackland, David C

    2016-04-01

    Normalization of gait data is performed to reduce the effects of intersubject variations due to physical characteristics. This study reports a multiple regression normalization approach for spatiotemporal gait data that takes into account intersubject variations in self-selected walking speed and physical properties including age, height, body mass, and sex. Spatiotemporal gait data including stride length, cadence, stance time, double support time, and stride time were obtained from healthy subjects including 782 children, 71 adults, 29 elderly subjects, and 28 elderly Parkinson's disease (PD) patients. Data were normalized using standard dimensionless equations, a detrending method, and a multiple regression approach. After normalization using dimensionless equations and the detrending method, weak to moderate correlations between walking speed, physical properties, and spatiotemporal gait features were observed (0.01 multiple regression method reduced these correlations to weak values (|r| multiple regression approach revealed significant differences in these features as well as in cadence, stance time, and stride time. The proposed multiple regression normalization may be useful in machine learning, gait classification, and clinical evaluation of pathological gait patterns.

  8. Improved kinect-based spatiotemporal and kinematic treadmill gait assessment.

    Science.gov (United States)

    Eltoukhy, Moataz; Oh, Jeonghoon; Kuenze, Christopher; Signorile, Joseph

    2017-01-01

    A cost-effective, clinician friendly gait assessment tool that can automatically track patients' anatomical landmarks can provide practitioners with important information that is useful in prescribing rehabilitative and preventive therapies. This study investigated the validity and reliability of the Microsoft Kinect v2 as a potential inexpensive gait analysis tool. Ten healthy subjects walked on a treadmill at 1.3 and 1.6m·s-1, as spatiotemporal parameters and kinematics were extracted concurrently using the Kinect and three-dimensional motion analysis. Spatiotemporal measures included step length and width, step and stride times, vertical and mediolateral pelvis motion, and foot swing velocity. Kinematic outcomes included hip, knee, and ankle joint angles in the sagittal plane. The absolute agreement and relative consistency between the two systems were assessed using interclass correlations coefficients (ICC2,1), while reproducibility between systems was established using Lin's Concordance Correlation Coefficient (rc). Comparison of ensemble curves and associated 90% confidence intervals (CI90) of the hip, knee, and ankle joint angles were performed to investigate if the Kinect sensor could consistently and accurately assess lower extremity joint motion throughout the gait cycle. Results showed that the Kinect v2 sensor has the potential to be an effective clinical assessment tool for sagittal plane knee and hip joint kinematics, as well as some spatiotemporal temporal variables including pelvis displacement and step characteristics during the gait cycle. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Artificial spatiotemporal touch inputs reveal complementary decoding in neocortical neurons.

    Science.gov (United States)

    Oddo, Calogero M; Mazzoni, Alberto; Spanne, Anton; Enander, Jonas M D; Mogensen, Hannes; Bengtsson, Fredrik; Camboni, Domenico; Micera, Silvestro; Jörntell, Henrik

    2017-04-04

    Investigations of the mechanisms of touch perception and decoding has been hampered by difficulties in achieving invariant patterns of skin sensor activation. To obtain reproducible spatiotemporal patterns of activation of sensory afferents, we used an artificial fingertip equipped with an array of neuromorphic sensors. The artificial fingertip was used to transduce real-world haptic stimuli into spatiotemporal patterns of spikes. These spike patterns were delivered to the skin afferents of the second digit of rats via an array of stimulation electrodes. Combined with low-noise intra- and extracellular recordings from neocortical neurons in vivo, this approach provided a previously inaccessible high resolution analysis of the representation of tactile information in the neocortical neuronal circuitry. The results indicate high information content in individual neurons and reveal multiple novel neuronal tactile coding features such as heterogeneous and complementary spatiotemporal input selectivity also between neighboring neurons. Such neuronal heterogeneity and complementariness can potentially support a very high decoding capacity in a limited population of neurons. Our results also indicate a potential neuroprosthetic approach to communicate with the brain at a very high resolution and provide a potential novel solution for evaluating the degree or state of neurological disease in animal models.

  10. Spatiotemporal Distribution of Chinavia hilaris (Hemiptera: Pentatomidae) in Corn Farmscapes

    Science.gov (United States)

    Cottrell, Ted E.; Tillman, P. Glynn

    2015-01-01

    The green stink bug, Chinavia hilaris (Say) (Hemiptera: Pentatomidae), is a pest of cotton in the southeastern United States but little is known concerning its spatiotemporal distribution in corn cropping systems. Therefore, the spatiotemporal distribution of C. hilaris in farmscapes, when corn was adjacent to cotton, peanut, or both, was examined weekly. The spatial patterns of C. hilaris counts were analyzed using Spatial Analysis by Distance Indices methodology. Interpolated maps of C. hilaris density were used to visualize abundance and distribution of C. hilaris in crops in corn–peanut–cotton farmscapes. This stink bug was detected in six of seven corn–cotton farmscapes, four of six corn–peanut farmscapes, and in both corn–peanut–cotton farmscapes. The frequency of C. hilaris in cotton (89.47%) was significantly higher than in peanut (7.02%) or corn (3.51%). This stink bug fed on noncrop hosts that grew in field borders adjacent to crops. The spatial distribution of C. hilaris in crops and the capture of C. hilaris adults and nymphs in pheromone-baited traps near noncrop hosts indicated that these hosts were sources of this stink bug dispersing into crops, primarily cotton. Significant aggregated spatial distributions were detected in cotton on some dates within corn–peanut–cotton farmscapes. Maps of local clustering indices depicted small patches of C. hilaris in cotton or cotton–sorghum at the peanut–cotton interface. Factors affecting the spatiotemporal dynamics of C. hilaris in corn farmscapes are discussed. PMID:25843581

  11. Spatiotemporal organization of exocytosis emerges during neuronal shape change.

    Science.gov (United States)

    Urbina, Fabio L; Gomez, Shawn M; Gupton, Stephanie L

    2018-01-19

    Neurite elongation and branching in developing neurons requires plasmalemma expansion, hypothesized to occur primarily via exocytosis. We posited that exocytosis in developing neurons and nonneuronal cells would exhibit distinct spatiotemporal organization. We exploited total internal reflection fluorescence microscopy to image vesicle-associated membrane protein (VAMP)-pHluorin-mediated exocytosis in mouse embryonic cortical neurons and interphase melanoma cells, and developed computer-vision software and statistical tools to uncover spatiotemporal aspects of exocytosis. Vesicle fusion behavior differed between vesicle types, cell types, developmental stages, and extracellular environments. Experiment-based mathematical calculations indicated that VAMP2-mediated vesicle fusion supplied excess material for the plasma membrane expansion that occurred early in neuronal morphogenesis, which was balanced by clathrin-mediated endocytosis. Spatial statistics uncovered distinct spatiotemporal regulation of exocytosis in the soma and neurites of developing neurons that was modulated by developmental stage, exposure to the guidance cue netrin-1, and the brain-enriched ubiquitin ligase tripartite motif 9. In melanoma cells, exocytosis occurred less frequently, with distinct spatial clustering patterns. © 2018 Urbina et al.

  12. Artificial spatiotemporal touch inputs reveal complementary decoding in neocortical neurons

    Science.gov (United States)

    Oddo, Calogero M.; Mazzoni, Alberto; Spanne, Anton; Enander, Jonas M. D.; Mogensen, Hannes; Bengtsson, Fredrik; Camboni, Domenico; Micera, Silvestro; Jörntell, Henrik

    2017-01-01

    Investigations of the mechanisms of touch perception and decoding has been hampered by difficulties in achieving invariant patterns of skin sensor activation. To obtain reproducible spatiotemporal patterns of activation of sensory afferents, we used an artificial fingertip equipped with an array of neuromorphic sensors. The artificial fingertip was used to transduce real-world haptic stimuli into spatiotemporal patterns of spikes. These spike patterns were delivered to the skin afferents of the second digit of rats via an array of stimulation electrodes. Combined with low-noise intra- and extracellular recordings from neocortical neurons in vivo, this approach provided a previously inaccessible high resolution analysis of the representation of tactile information in the neocortical neuronal circuitry. The results indicate high information content in individual neurons and reveal multiple novel neuronal tactile coding features such as heterogeneous and complementary spatiotemporal input selectivity also between neighboring neurons. Such neuronal heterogeneity and complementariness can potentially support a very high decoding capacity in a limited population of neurons. Our results also indicate a potential neuroprosthetic approach to communicate with the brain at a very high resolution and provide a potential novel solution for evaluating the degree or state of neurological disease in animal models. PMID:28374841

  13. Modeling spatiotemporal dynamics of DNA methylation

    DEFF Research Database (Denmark)

    Lövkvist, Cecilia Elisabet

    Epigenetics explains how cells with identical genetic material can have different gene expression patterns and thereby varying phenotypes. By the definition used in this thesis, a “mark” is considered to be epigenetic, if it affects gene expression, is stable over time, and is inherited upon cell...... division. The patterns of epigentic marks depend on enzymes that ensure their maintenance and introduction. Using theoretical models, this thesis proposes new mechanisms for how enzymes operate to maintain patterns of epigenetic marks. Through analysis of experimental data this work gives new insight...... into how epigenetic marks are distributed in the human genome. In the first part of the thesis, we investigate DNA methylation and maintenance of methylation patterns throughout cell division. We argue that collaborative models, those where the methylation of CpG sites depends on the methylation status...

  14. Exploiting Spatio-Temporal Correlation for Reliable Information Transport in WSNs

    Directory of Open Access Journals (Sweden)

    Faisal Karim Shaikh

    2011-01-01

    Full Text Available Delivering reliable services in service oriented architectures entails the underlying basis of having communication network models and well structured systems. With the rapid proliferation of ad-hoc mode of communication the reliable delivery of services increasingly encounter new communication and network perturbations. Empirically the core of service delivery in WSNs (Wireless Sensor Networks is information transport from the sensor nodes to the sink node where the service resides. In this work we provide a reliable information transport for enhanced service delivery by using spatio-temporal correlation in WSN. The classification for different types of information required by the services is also presented. To overcome dynamic network conditions and evolving service requirements an adaptive retransmission mechanism based on spatial correlation is utilized. Simulation results show that the proposed solutions provide service specific reliability and save expensive retransmissions and thus provide energy efficient solution.

  15. REVIEWS OF TOPICAL PROBLEMS: Spatio-temporal problems of locomotion control

    Science.gov (United States)

    Smolyaninov, Vladimir V.

    2000-10-01

    The problem of the spatio-temporal construction of legged movements involves structural freedoms due to the multi-link structure of the extremities, kinematic freedoms of the stepping cycle, and interextremity coordination freedoms, whose purposive organization is established by means of appropriate synergies, i.e. additional functional links the brain's control system forms. The main focus of attention in this work is on the kinematic and coordination synergies of the legged movements of humans and animals. The comparative historical analysis of experimental data and modelling metaphors concentrates on obtaining a unified description, whereas the ultimate mathematical metaphor reduces to space-time geometry, with base step synergies as its invariants. Thus, the concept of a synergetic organization for biomechanical movement freedoms is transformed to the geochronometry concept, actually a modification of Minkowskian geometry. To determine the spectrum of possible geochronometries, the consequences of a generalized 'postulate of a constant speed of light' are studied and different models of wave chronometers compared.

  16. Neurobiological mechanisms behind the spatiotemporal illusions of awareness that are used for advocating prediction or postdiction

    Directory of Open Access Journals (Sweden)

    Talis eBachmann

    2013-01-01

    Full Text Available The fact that it takes time for the brain to process information from the changing environment underlies many experimental phenomena of awareness of spatiotemporal events, including a number of astonishing illusions. These phenomena have been explained from the predictive and postdictive theoretical perspectives. Here I describe the most extensively studied phenomena in order to see how well the two perspectives can explain them. Next, the neurobiological perceptual retouch mechanism of producing stimulation awareness is characterized and its work in causing the listed illusions is described. A perspective on how brain mechanisms of conscious perception produce the phenomena supportive of the postdictive view is presented in this article. At the same time, some of the phenomena cannot be explained by the traditional postdictive account, but can be interpreted from the perceptual retouch theory perspective.

  17. Vortex-based spatiotemporal characterization of nonlinear flows

    Science.gov (United States)

    Byrne, Gregory A.

    Although the ubiquity of vortices in nature has been recognized by artists for over seven centuries, it was the work of artist and scientist Leonardo da Vinci that provided the monumental transition from an aesthetic form to a scientific tool. DaVinci used vortices to describe the motions he observed in air currents, flowing water and blood flow in the human heart. Five centuries later, the Navier-Stokes equations allow us to recreate the swirling motions of fluid observed in nature. Computational fluid dynamic (CFD) simulations have provided a lens through which to study the role of vortices in a wide variety of modern day applications. The research summarized below represents an effort to look through this lens and bring into focus the practical use of vortices in describing nonlinear flows. Vortex-based spatiotemporal characterizations are obtained using two specific mathematical tools: vortex core lines (VCL) and proper orthogonal decomposition (POD). By applying these tools, we find that vortices continue to provide new insights in the realm of biofluids, urban flows and the phase space of dynamical systems. The insights we have gained are described in this thesis. Our primary focus is on biofluids. Specifically, we seek to gain new insights into the connection between vortices and vascular diseases in order to provide more effective methods for clinical diagnosis and treatment. We highlight several applications in which VCL and POD are used to characterize the flow conditions in a heart pump, identify stenosis in carotid arteries and validate numerical models against PIV-based experimental data. Next, we quantify the spatial complexity and temporal stability of hemodynamics generated by a database of 210 patient-specific aneurysm geometries. Visual classifications of the hemodynamics are compared to the automated, quantitative classifications. The quantities characterizing the hemodynamics are then compared to clinical data to determine conditions that are

  18. Ensemble reconstruction of spatio-temporal extreme low-flow events in France since 1871

    Science.gov (United States)

    Caillouet, Laurie; Vidal, Jean-Philippe; Sauquet, Eric; Devers, Alexandre; Graff, Benjamin

    2017-06-01

    The length of streamflow observations is generally limited to the last 50 years even in data-rich countries like France. It therefore offers too small a sample of extreme low-flow events to properly explore the long-term evolution of their characteristics and associated impacts. To overcome this limit, this work first presents a daily 140-year ensemble reconstructed streamflow dataset for a reference network of near-natural catchments in France. This dataset, called SCOPE Hydro (Spatially COherent Probabilistic Extended Hydrological dataset), is based on (1) a probabilistic precipitation, temperature, and reference evapotranspiration downscaling of the Twentieth Century Reanalysis over France, called SCOPE Climate, and (2) continuous hydrological modelling using SCOPE Climate as forcings over the whole period. This work then introduces tools for defining spatio-temporal extreme low-flow events. Extreme low-flow events are first locally defined through the sequent peak algorithm using a novel combination of a fixed threshold and a daily variable threshold. A dedicated spatial matching procedure is then established to identify spatio-temporal events across France. This procedure is furthermore adapted to the SCOPE Hydro 25-member ensemble to characterize in a probabilistic way unrecorded historical events at the national scale. Extreme low-flow events are described and compared in a spatially and temporally homogeneous way over 140 years on a large set of catchments. Results highlight well-known recent events like 1976 or 1989-1990, but also older and relatively forgotten ones like the 1878 and 1893 events. These results contribute to improving our knowledge of historical events and provide a selection of benchmark events for climate change adaptation purposes. Moreover, this study allows for further detailed analyses of the effect of climate variability and anthropogenic climate change on low-flow hydrology at the scale of France.

  19. Measures of short-term memory: a historical review.

    Science.gov (United States)

    Richardson, John T E

    2007-07-01

    Following Ebbinghaus (1885/1964), a number of procedures have been devised to measure short-term memory using immediate serial recall: digit span, Knox's (1913) cube imitation test and Corsi's (1972) blocks task. Understanding the cognitive processes involved in these tasks was obstructed initially by the lack of a coherent concept of short-term memory and later by the mistaken assumption that short-term and long-term memory reflected distinct processes as well as different kinds of experimental task. Despite its apparent conceptual simplicity, a variety of cognitive mechanisms are responsible for short-term memory, and contemporary theories of working memory have helped to clarify these. Contrary to the earliest writings on the subject, measures of short-term memory do not provide a simple measure of mental capacity, but they do provide a way of understanding some of the key mechanisms underlying human cognition.

  20. Adaptive changes in human memory: a literature review

    Directory of Open Access Journals (Sweden)

    Agnieszka Laura Sabiniewicz

    2017-07-01

    Full Text Available The paper contains a review of the literature concerning memory abilities and human senses performance under different environmental circumstances. A number of studies indicated that environment has a significant impact on human senses functioning. It can affect it in a mechanical way, by a chronic exposure to potentially harmful substances or processes in different work environments. Also, some cognitive abilities that have evolved to perform evolutionary essential functions lost their importance because of the change of environment impact. Moreover, training can be a source of improvement of both human senses and cognitive abilities, as well. That might suggest that, while using, under different environmental circumstances different cognitive abilities develop. We take into a particular consideration human memory and its role, show current studies in this field and suggest new research directions.

  1. Data-driven spatio-temporal RGBD feature encoding for action recognition in operating rooms.

    Science.gov (United States)

    Twinanda, Andru P; Alkan, Emre O; Gangi, Afshin; de Mathelin, Michel; Padoy, Nicolas

    2015-06-01

    -rigid spatio-temporal feature encoding scheme provides more discriminative histogram representations than the rigid counterpart. To the best of our knowledge, this is also the first work that presents action recognition results on multi-view RGBD data recorded in the OR.

  2. Classification of motor intent in transradial amputees using sonomyography and spatio-temporal image analysis

    Science.gov (United States)

    Hariharan, Harishwaran; Aklaghi, Nima; Baker, Clayton A.; Rangwala, Huzefa; Kosecka, Jana; Sikdar, Siddhartha

    2016-04-01

    In spite of major advances in biomechanical design of upper extremity prosthetics, these devices continue to lack intuitive control. Conventional myoelectric control strategies typically utilize electromyography (EMG) signal amplitude sensed from forearm muscles. EMG has limited specificity in resolving deep muscle activity and poor signal-to-noise ratio. We have been investigating alternative control strategies that rely on real-time ultrasound imaging that can overcome many of the limitations of EMG. In this work, we present an ultrasound image sequence classification method that utilizes spatiotemporal features to describe muscle activity and classify motor intent. Ultrasound images of the forearm muscles were obtained from able-bodied subjects and a trans-radial amputee while they attempted different hand movements. A grid-based approach is used to test the feasibility of using spatio-temporal features by classifying hand motions performed by the subjects. Using the leave-one-out cross validation on image sequences acquired from able-bodied subjects, we observe that the grid-based approach is able to discern four hand motions with 95.31% accuracy. In case of the trans-radial amputee, we are able to discern three hand motions with 80% accuracy. In a second set of experiments, we study classification accuracy by extracting spatio-temporal sub-sequences the depict activity due to the motion of local anatomical interfaces. Short time and space limited cuboidal sequences are initially extracted and assigned an optical flow behavior label, based on a response function. The image space is clustered based on the location of cuboids and features calculated from the cuboids in each cluster. Using sequences of known motions, we extract feature vectors that describe said motion. A K-nearest neighbor classifier is designed for classification experiments. Using the leave-one-out cross validation on image sequences for an amputee subject, we demonstrate that the classifier is

  3. Nano-islands Based Charge Trapping Memory: A Scalability Study

    KAUST Repository

    Elatab, Nazek

    2017-10-19

    Zinc-oxide (ZnO) and zirconia (ZrO2) metal oxides have been studied extensively in the past few decades with several potential applications including memory devices. In this work, a scalability study, based on the ITRS roadmap, is conducted on memory devices with ZnO and ZrO2 nano-islands charge trapping layer. Both nano-islands are deposited using atomic layer deposition (ALD), however, the different sizes, distribution and properties of the materials result in different memory performance. The results show that at the 32-nm node charge trapping memory with 127 ZrO2 nano-islands can provide a 9.4 V memory window. However, with ZnO only 31 nano-islands can provide a window of 2.5 V. The results indicate that ZrO2 nano-islands are more promising than ZnO in scaled down devices due to their higher density, higher-k, and absence of quantum confinement effects.

  4. Reasoning and dyslexia: is visual memory a compensatory resource?

    Science.gov (United States)

    Bacon, Alison M; Handley, Simon J

    2014-11-01

    Effective reasoning is fundamental to problem solving and achievement in education and employment. Protocol studies have previously suggested that people with dyslexia use reasoning strategies based on visual mental representations, whereas non-dyslexics use abstract verbal strategies. This research presents converging evidence from experimental and individual differences perspectives. In Experiment 1, dyslexic and non-dyslexic participants were similarly accurate on reasoning problems, but scores on a measure of visual memory ability only predicted reasoning accuracy for dyslexics. In Experiment 2, a secondary task loaded visual memory resources during concurrent reasoning. Dyslexics were significantly less accurate when reasoning under conditions of high memory load and showed reduced ability to subsequently recall the visual stimuli, suggesting that the memory and reasoning tasks were competing for the same visual cognitive resource. The results are consistent with an explanation based on limitations in the verbal and executive components of working memory in dyslexia and the use of compensatory visual strategies for reasoning. There are implications for cognitive activities that do not readily support visual thinking, whether in education, employment or less formal everyday settings. Copyright © 2014 John Wiley & Sons, Ltd.

  5. Australian Aboriginal Memoir and Memory: A Stolen Generations Trauma Narrative

    Directory of Open Access Journals (Sweden)

    Justine Seran

    2015-10-01

    Full Text Available This article proposes a re-reading of Aboriginal author Sally Morgan’s Stolen Generations narrative My Place (1987 in post-Apology Australia (2008–present. The novel tells the story of Morgan’s discovery of her maternal Aboriginal origins through the life-stories of her mother and grandmother; the object of a quest for the past that is both relational and matrilineal; incorporating elements of autobiography and as-told-to memoirs to create a form of choral autoethnography. Morgan’s text explores the intergenerational consequences of child removal in the Aboriginal context and is representative of Indigenous-authored narratives in its suggestion that the children and grand-children of victims of colonial policies and practices can work through the trauma of their ancestors. I examine the literary processes of decolonization of the Indigenous writing/written self and community; as well as strategies for individual survival and cultural survivance in the Australian settler colonial context; especially visible through the interactions between traumatic memories and literary memoirs, a genre neglected by trauma theory’s concern with narrative fragmentation and the proliferation of “themed” life-writing centered on a traumatic event. This article calls for a revision of trauma theory’s Eurocentrism through scholarly engagement with Indigenous experiences such as Morgan’s and her family in order to broaden definitions and take into account collective, historical, and inherited trauma.

  6. Gender differences in object location memory: a meta-analysis.

    Science.gov (United States)

    Voyer, Daniel; Postma, Albert; Brake, Brandy; Imperato-McGinley, Julianne

    2007-02-01

    The goal of the present study was to quantify the magnitude of gender differences in object location memory tasks. A total of 123 effect sizes (d) drawn from 36 studies were included in a meta-analysis using a hierarchical approach. Object identity memory (37 effect sizes) and object location memory (86 effect sizes) tasks were analyzed separately. Object identity memory task showed significant gender differences that were homogeneous and in favor of women. For the object location memory tasks, effect sizes had to be partitioned by age (younger than 13, between 13 and 18, older than 18), object type (common, uncommon, gender neutral, geometric, masculine, feminine), scoring method (accuracy, time, distance), and type of measure (recall, recognition) to achieve homogeneity. Significant gender differences in favor of females were obtained in all clusters above the age of 13, with the exception of feminine, uncommon, and gender-neutral objects. Masculine objects and measures of distance produced significant effects in favor of males. Implications of these results for future work and for theoretical interpretations are discussed.

  7. Spatiotemporal dynamics of argument retrieval and reordering: an fMRI and EEG study on sentence processing

    Directory of Open Access Journals (Sweden)

    Lars eMeyer

    2012-12-01

    Full Text Available In sentence processing, it is still unclear how the neural language network successfully establishes argument–verb dependencies in its spatiotemporal neuronal dynamics. Previous work has suggested that the establishment of subject-verb and object–verb dependencies requires argument retrieval from working memory, and that dependency establishment in object-first sentences additionally necessitates argument reordering. We examine the spatiotemporal neuronal dynamics of the brain regions that subserve these sub-processes by crossing an argument-reordering factor (i.e., subject-first vs. object-first sentences with an argument retrieval factor (i.e., short vs. long argument–verb dependencies in German. Using functional magnetic resonance imaging (fMRI, we found that reordering demands focally activate the left pars opercularis (Broca’s area, while storage and retrieval demands activated left temporo-parietal (TP regions. In addition, when analyzing the time course of fMRI-informed equivalent current dipole sources in the EEG at the subcategorizing verb, we found that activity in the TP region occurs relatively early (40–180 ms, followed by activity in Broca’s area (300–500 ms. These findings were matched by topographical correlation analyses of fMRI activations in EEG sensor space, showing that, in the scalp potential, TP region activity surfaces as an early positivity and IFG activity as a later positivity in the scalp potential. These results provide fine-grained evidence for spatiotemporally separable sub-processes of argument retrieval and reordering in sentence processing.

  8. Spatio-Temporal Encoding in Medical Ultrasound Imaging

    DEFF Research Database (Denmark)

    Gran, Fredrik

    2005-01-01

    In this dissertation two methods for spatio-temporal encoding in medical ultrasound imaging are investigated. The first technique is based on a frequency division approach. Here, the available spectrum of the transducer is divided into a set of narrow bands. A waveform is designed for each band...... are also included in the dissertation. The second method is based on encoding the transmitters with pseudo-random sequences. The signals can be separated after only one transmission using an estimation based technique. Broadband decoding can, therefore, be performed at the receiver after a single...

  9. Instability and Spatiotemporal Dynamics of Alternans in Paced Cardiac Tissue

    Science.gov (United States)

    Echebarria, Blas; Karma, Alain

    2002-05-01

    We derive an equation that governs the spatiotemporal dynamics of small amplitude alternans in paced cardiac tissue. We show that a pattern-forming linear instability leads to the spontaneous formation of stationary or traveling waves whose nodes divide the tissue into regions with opposite phase of oscillation of action potential duration. This instability is important because it creates dynamically a heterogeneous electrical substrate for the formation of conduction blocks and the induction of fibrillation if the tissue size exceeds a fraction of the pattern wavelength. We derive an analytical expression for this wavelength as a function of three basic length scales related to dispersion and intercellular electrical coupling.

  10. Parallel Spatiotemporal Spectral Clustering with Massive Trajectory Data

    Science.gov (United States)

    Gu, Y. Z.; Qin, K.; Chen, Y. X.; Yue, M. X.; Guo, T.

    2017-09-01

    Massive trajectory data contains wealth useful information and knowledge. Spectral clustering, which has been shown to be effective in finding clusters, becomes an important clustering approaches in the trajectory data mining. However, the traditional spectral clustering lacks the temporal expansion on the algorithm and limited in its applicability to large-scale problems due to its high computational complexity. This paper presents a parallel spatiotemporal spectral clustering based on multiple acceleration solutions to make the algorithm more effective and efficient, the performance is proved due to the experiment carried out on the massive taxi trajectory dataset in Wuhan city, China.

  11. Spatiotemporal resonances in mixing of open viscous fluids

    DEFF Research Database (Denmark)

    Okkels, Fridolin; Tabeling, Patrick

    2004-01-01

    In this Letter, we reveal a new dynamical phenomenon, called "spatiotemporal resonance," which is expected to take place in a broad range of viscous, periodically forced, open systems. The observation originates from a numerical and theoretical analysis of a micromixer, and is supported...... by preliminary experimental observations. The theoretical model nicely matches the numerical results, which again is supported by the experiment. Because of the general nature of the phenomenon, this phenomenon is not limited to microsystems. Because of the resonances, a slight tuning of the control parameters...

  12. Spatiotemporal extreme events in a laser with a saturable absorber

    Science.gov (United States)

    Rimoldi, Cristina; Barland, Stéphane; Prati, Franco; Tissoni, Giovanna

    2017-02-01

    We study extreme events occurring in the transverse (x ,y ) section of the field emitted by a broad-area semiconductor laser with a saturable absorber. The spatiotemporal events on which we perform the statistical analysis are identified as maxima of the field intensity in the three-dimensional space (x ,y ,t ) . We identify regions in the parameter space where extreme events are more likely to occur and we study the connection of those extreme events with the cavity solitons that are known to exist in the same system, both stationary and self-pulsing.

  13. Spatiotemporal Chaos Induces Extreme Events in an Extended Microcavity Laser

    Science.gov (United States)

    Selmi, F.; Coulibaly, S.; Loghmari, Z.; Sagnes, I.; Beaudoin, G.; Clerc, M. G.; Barbay, S.

    2016-01-01

    Extreme events such as rogue waves in optics and fluids are often associated with the merging dynamics of coherent structures. We present experimental and numerical results on the physics of extreme event appearance in a spatially extended semiconductor microcavity laser with an intracavity saturable absorber. This system can display deterministic irregular dynamics only, thanks to spatial coupling through diffraction of light. We have identified parameter regions where extreme events are encountered and established the origin of this dynamics in the emergence of deterministic spatiotemporal chaos, through the correspondence between the proportion of extreme events and the dimension of the strange attractor.

  14. Spatiotemporal mathematical modelling of mutations of the dhps gene in African Plasmodium falciparum.

    Science.gov (United States)

    Flegg, Jennifer A; Patil, Anand P; Venkatesan, Meera; Roper, Cally; Naidoo, Inbarani; Hay, Simon I; Sibley, Carol Hopkins; Guerin, Philippe J

    2013-07-17

    Plasmodium falciparum has repeatedly evolved resistance to first-line anti-malarial drugs, thwarting efforts to control and eliminate the disease and in some period of time this contributed largely to an increase in mortality. Here a mathematical model was developed to map the spatiotemporal trends in the distribution of mutations in the P. falciparum dihydropteroate synthetase (dhps) gene that confer resistance to the anti-malarial sulphadoxine, and are a useful marker for the combination of alleles in dhfr and dhps that is highly correlated with resistance to sulphadoxine-pyrimethamine (SP). The aim of this study was to present a proof of concept for spatiotemporal modelling of trends in anti-malarial drug resistance that can be applied to monitor trends in resistance to components of artemisinin combination therapy (ACT) or other anti-malarials, as they emerge or spread. Prevalence measurements of single nucleotide polymorphisms in three codon positions of the dihydropteroate synthetase (dhps) gene from published studies of dhps mutations across Africa were used. A model-based geostatistics approach was adopted to create predictive surfaces of the dhps540E mutation over the spatial domain of sub-Saharan Africa from 1990-2010. The statistical model was implemented within a Bayesian framework and hence quantified the associated uncertainty of the prediction of the prevalence of the dhps540E mutation in sub-Saharan Africa. The maps presented visualize the changing prevalence of the dhps540E mutation in sub-Saharan Africa. These allow prediction of space-time trends in the parasite resistance to SP, and provide probability distributions of resistance prevalence in places where no data are available as well as insight on the spread of resistance in a way that the data alone do not allow. The results of this work will be extended to design optimal sampling strategies for the future molecular surveillance of resistance, providing a proof of concept for similar

  15. A flexible spatiotemporal method for fusing satellite images with different resolutions

    Science.gov (United States)

    Xiaolin Zhu; Eileen H. Helmer; Feng Gao; Desheng Liu; Jin Chen; Michael A. Lefsky

    2016-01-01

    Studies of land surface dynamics in heterogeneous landscapes often require remote sensing datawith high acquisition frequency and high spatial resolution. However, no single sensor meets this requirement. This study presents a new spatiotemporal data fusion method, the Flexible Spatiotemporal DAta Fusion (FSDAF) method, to generate synthesized frequent high spatial...

  16. Assessment of spatio-temporal gait parameters from trunk accelerations during human walking

    NARCIS (Netherlands)

    Zijlstra, W; Hof, AL

    2003-01-01

    This paper studies the feasibility of an analysis of spatio-temporal gait parameters based upon accelerometry. To this purpose, acceleration patterns of the trunk and their relationships with spatio-temporal gait parameters were analysed in healthy subjects. Based on model predictions of the body's

  17. Spatiotemporal suicide risk in Germany: A longitudinal study 2007-11

    NARCIS (Netherlands)

    Helbich, M|info:eu-repo/dai/nl/370530349; Plener, P; Hartung, S; Blüml, V

    2017-01-01

    Despite comprehensive prevention programs in Germany, suicide has been on the rise again since 2007. The underlying reasons and spatiotemporal risk patterns are poorly understood. We assessed the spatiotemporal risk of suicide per district attributable to multiple risk and protective factors

  18. Spatiotemporal coupled-mode theory in dispersive media under a dynamic modulation

    CERN Document Server

    Dana, Brenda; Bahabad, Alon

    2014-01-01

    A simple and general formalism for mode coupling by a spatial, temporal or spatiotemporal perturbation in dispersive materials is developed. This formalism can be used for studying various linear and non-linear optical interactions involving a dynamic modulation of the interaction parameters such as non-reciprocal phenomena, time reversal of signals and spatiotemporal quasi phase matching

  19. An implicit spatiotemporal shape model for human activity localization and recognition

    NARCIS (Netherlands)

    Oikonomopoulos, A.; Patras, I.; Pantic, Maja

    2009-01-01

    In this paper we address the problem of localisation and recognition of human activities in unsegmented image sequences. The main contribution of the proposed method is the use of an implicit representation of the spatiotemporal shape of the activity which relies on the spatiotemporal localization

  20. SPATIOTEMPORAL VISUALIZATION OF TSUNAMI WAVES USING KML ON GOOGLE EARTH

    Directory of Open Access Journals (Sweden)

    H. Mohammadi

    2017-09-01

    Full Text Available Disaster risk is a function of hazard and vulnerability. Risk is defined as the expected losses, including lives, personal injuries, property damages, and economic disruptions, due to a particular hazard for a given area and time period. Risk assessment is one of the key elements of a natural disaster management strategy as it allows for better disaster mitigation and preparation. It provides input for informed decision making, and increases risk awareness among decision makers and other stakeholders. Virtual globes such as Google Earth can be used as a visualization tool. Proper spatiotemporal graphical representations of the concerned risk significantly reduces the amount of effort to visualize the impact of the risk and improves the efficiency of the decision-making process to mitigate the impact of the risk. The spatiotemporal visualization of tsunami waves for disaster management process is an attractive topic in geosciences to assist investigation of areas at tsunami risk. In this paper, a method for coupling virtual globes with tsunami wave arrival time models is presented. In this process we have shown 2D+Time of tsunami waves for propagation and inundation of tsunami waves, both coastal line deformation, and the flooded areas. In addition, the worst case scenario of tsunami on Chabahar port derived from tsunami modelling is also presented using KML on google earth.

  1. plotKML: Scientific Visualization of Spatio-Temporal Data

    Directory of Open Access Journals (Sweden)

    Tomislav Hengl

    2015-02-01

    Full Text Available plotKML is an R package that provides methods for writing the most common R spatial classes into KML files. It builds up on the existing XML parsing functionality (XML package, and provides similar plotting functionality as the lattice package. Its main objective is to provide a simple interface to generate KML files with a small number of arguments, and allows users to visually explore spatio-temporal data available in R: points, polygons, gridded maps, trajectory-type data, vertical profiles, ground photographs, time series vector objects or raster images, along with the results of spatial analysis such as geostatistical mapping, spatial simulations of vector and gridded objects, optimized sampling designs, species distribution models and similar. A generic plotKML( function automatically determines the parsing order and visualizes data directly from R; lower level functions can be combined to allow for new user-created visualization templates. In comparison to other packages writing KML, plotKML seems to be more object oriented, it links more closely to the existing R classes for spatio-temporal data (sp, spacetime and raster packages than the alternatives, and provides users with the possibility to create their own templates.

  2. Spatiotemporal Visualization of Tsunami Waves Using Kml on Google Earth

    Science.gov (United States)

    Mohammadi, H.; Delavar, M. R.; Sharifi, M. A.; Pirooz, M. D.

    2017-09-01

    Disaster risk is a function of hazard and vulnerability. Risk is defined as the expected losses, including lives, personal injuries, property damages, and economic disruptions, due to a particular hazard for a given area and time period. Risk assessment is one of the key elements of a natural disaster management strategy as it allows for better disaster mitigation and preparation. It provides input for informed decision making, and increases risk awareness among decision makers and other stakeholders. Virtual globes such as Google Earth can be used as a visualization tool. Proper spatiotemporal graphical representations of the concerned risk significantly reduces the amount of effort to visualize the impact of the risk and improves the efficiency of the decision-making process to mitigate the impact of the risk. The spatiotemporal visualization of tsunami waves for disaster management process is an attractive topic in geosciences to assist investigation of areas at tsunami risk. In this paper, a method for coupling virtual globes with tsunami wave arrival time models is presented. In this process we have shown 2D+Time of tsunami waves for propagation and inundation of tsunami waves, both coastal line deformation, and the flooded areas. In addition, the worst case scenario of tsunami on Chabahar port derived from tsunami modelling is also presented using KML on google earth.

  3. MINING SPATIOTEMPORAL PATTERNS OF THE ELDER’S DAILY MOVEMENT

    Directory of Open Access Journals (Sweden)

    C. R. Chen

    2016-06-01

    Full Text Available With rapid developments in wearable device technology, a vast amount of spatiotemporal data, such as people’s movement and physical activities, are generated. Information derived from the data reveals important knowledge that can contribute a long-term care and psychological assessment of the elders’ living condition especially in long-term care institutions. This study aims to develop a method to investigate the spatial-temporal movement patterns of the elders with their outdoor trajectory information. To achieve the goal, GPS based location data of the elderly subjects from long-term care institutions are collected and analysed with geographic information system (GIS. A GIS statistical model is developed to mine the elderly subjects’ spatiotemporal patterns with the location data and represent their daily movement pattern at particular time. The proposed method first finds the meaningful trajectory and extracts the frequent patterns from the time-stamp location data. Then, a density-based clustering method is used to identify the major moving range and the gather/stay hotspot in both spatial and temporal dimensions. The preliminary results indicate that the major moving area of the elderly people encompasses their dorm and has a short moving distance who often stay in the same site. Subjects’ outdoor appearance are corresponded to their life routine. The results can be useful for understanding elders’ social network construction, risky area identification and medical care monitoring.

  4. Unique spatiotemporal requirements for intraflagellar transport genes during forebrain development.

    Directory of Open Access Journals (Sweden)

    John Snedeker

    Full Text Available Primary cilia are organelles extended from virtually all cells and are required for the proper regulation of a number of canonical developmental pathways. The role in cortical development of proteins important for ciliary form and function is a relatively understudied area. Here we have taken a genetic approach to define the role in forebrain development of three intraflagellar transport proteins known to be important for primary cilia function. We have genetically ablated Kif3a, Ift88, and Ttc21b in a series of specific spatiotemporal domains. The resulting phenotypes allow us to draw several conclusions. First, we conclude that the Ttc21b cortical phenotype is not due to the activity of Ttc21b within the brain itself. Secondly, some of the most striking phenotypes are from ablations in the neural crest cells and the adjacent surface ectoderm indicating that cilia transduce critical tissue-tissue interactions in the developing embryonic head. Finally, we note striking differences in phenotypes from ablations only one embryonic day apart, indicating very discrete spatiotemporal requirements for these three genes in cortical development.

  5. Spatio-temporal statistical models with applications to atmospheric processes

    Energy Technology Data Exchange (ETDEWEB)

    Wikle, Christopher K. [Iowa State Univ., Ames, IA (United States)

    1996-01-01

    This doctoral dissertation is presented as three self-contained papers. An introductory chapter considers traditional spatio-temporal statistical methods used in the atmospheric sciences from a statistical perspective. Although this section is primarily a review, many of the statistical issues considered have not been considered in the context of these methods and several open questions are posed. The first paper attempts to determine a means of characterizing the semiannual oscillation (SAO) spatial variation in the northern hemisphere extratropical height field. It was discovered that the midlatitude SAO in 500hPa geopotential height could be explained almost entirely as a result of spatial and temporal asymmetries in the annual variation of stationary eddies. It was concluded that the mechanism for the SAO in the northern hemisphere is a result of land-sea contrasts. The second paper examines the seasonal variability of mixed Rossby-gravity waves (MRGW) in lower stratospheric over the equatorial Pacific. Advanced cyclostationary time series techniques were used for analysis. It was found that there are significant twice-yearly peaks in MRGW activity. Analyses also suggested a convergence of horizontal momentum flux associated with these waves. In the third paper, a new spatio-temporal statistical model is proposed that attempts to consider the influence of both temporal and spatial variability. This method is mainly concerned with prediction in space and time, and provides a spatially descriptive and temporally dynamic model.

  6. Research on Process-oriented Spatio-temporal Data Model

    Directory of Open Access Journals (Sweden)

    XUE Cunjin

    2016-02-01

    Full Text Available According to the analysis of the present status and existing problems of spatio-temporal data models developed in last 20 years,this paper proposes a process-oriented spatio-temporal data model (POSTDM,aiming at representing,organizing and storing continuity and gradual geographical entities. The dynamic geographical entities are graded and abstracted into process objects series from their intrinsic characteristics,which are process objects,process stage objects,process sequence objects and process state objects. The logical relationships among process entities are further studied and the structure of UML models and storage are also designed. In addition,through the mechanisms of continuity and gradual changes impliedly recorded by process objects,and the modes of their procedure interfaces offered by the customized ObjcetStorageTable,the POSTDM can carry out process representation,storage and dynamic analysis of continuity and gradual geographic entities. Taking a process organization and storage of marine data as an example,a prototype system (consisting of an object-relational database and a functional analysis platform is developed for validating and evaluating the model's practicability.

  7. Gait recognition using spatio-temporal silhouette-based features

    Science.gov (United States)

    Sabir, Azhin; Al-jawad, Naseer; Jassim, Sabah

    2013-05-01

    This paper presents a new algorithm for human gait recognition based on Spatio-temporal body biometric features using wavelet transforms. The proposed algorithm extracts the Gait cycle depending on the width of boundary box from a sequence of Silhouette images. Gait recognition is based on feature level fusion of three feature vectors: the gait spatio-temporal feature represented by the distances between (feet, knees, hands, shoulders, and height); binary difference between consecutive frames of the silhouette for each leg detected separately based on hamming distance; a vector of statistical parameters captured from the wavelet low frequency domain. The fused feature vector is subjected to dimension reduction using linear discriminate analysis. The Nearest Neighbour with a certain threshold used for classification. The threshold is obtained by experiment from a set of data captured from the CASIA database. We shall demonstrate that our method provides a non-traditional identification based on certain threshold to classify the outsider members as non-classified members.

  8. The Effects of Ageing on Visual Spatiotemporal Processing

    Directory of Open Access Journals (Sweden)

    M Kunchulia

    2014-08-01

    Full Text Available In a previous study, we showed that visual spatiotemporal processing deteriorates with healthy ageing (Roinishvili et al, 2011, Vision Research, 51(4:417-23. Here, we used backward masking to investigate the underlying mechanisms. First, thirty-three older (M = 65.3 years and ten younger adults (M = 24.3 years had to indicate the offset direction of a vernier that was masked by a 5- or 25-element grating. We replicated results from our previous study with stronger masking effects in older compared to younger adults. Interestingly, stimulus onset asynchronies (SOAs between target and mask were significantly longer in older adults with individually determined vernier durations above 30msec, compared to older adults with vernier durations similar to younger adults. Second, we used two different masks with either a spatial or a temporal inhomogeneity. Older adults with vernier durations that were similar to young controls were sensitive to temporal and spatial inhomogeneities in the mask indicating fast and spatially intact processing. However, older adults whose individually determined vernier durations were significantly longer than those of younger adults were not as sensitive to temporal and spatial inhomogeneities in the mask, indicating that small spatiotemporal details are filtered out, which is highly likely due to low-pass filtered vision.

  9. Spatio-temporal avalanche forecasting with Support Vector Machines

    Directory of Open Access Journals (Sweden)

    A. Pozdnoukhov

    2011-02-01

    Full Text Available This paper explores the use of the Support Vector Machine (SVM as a data exploration tool and a predictive engine for spatio-temporal forecasting of snow avalanches. Based on the historical observations of avalanche activity, meteorological conditions and snowpack observations in the field, an SVM is used to build a data-driven spatio-temporal forecast for the local mountain region. It incorporates the outputs of simple physics-based and statistical approaches used to interpolate meteorological and snowpack-related data over a digital elevation model of the region. The interpretation of the produced forecast is discussed, and the quality of the model is validated using observations and avalanche bulletins of the recent years. The insight into the model behaviour is presented to highlight the interpretability of the model, its abilities to produce reliable forecasts for individual avalanche paths and sensitivity to input data. Estimates of prediction uncertainty are obtained with ensemble forecasting. The case study was carried out using data from the avalanche forecasting service in the Locaber region of Scotland, where avalanches are forecast on a daily basis during the winter months.

  10. Environmental Data Science: Discovering Hidden System of Spatiotemporal Groundwater

    Science.gov (United States)

    Lee, C. H.; Yu, H. L.

    2016-12-01

    Groundwater has been well known as one of the major water resources in the regions with water scarcity problems. As the results of the increasing water shortage concerns around the world recently, it is essential to realize the spatial and temporal variation of groundwater levels for water resources management. In general, hydrological models have been developed to describe groundwater flow system across space and time. Since hydrological models are simplified and conceptual representations, both parameter and model uncertainties play important roles while constructing. The performance of hydrological models depends on the subjective of hydrologists due to the uncertainties. However, environmental data like groundwater level observations is abundant and prevalent nowadays. It provides an opportunity to enhance previous subjective modeling in hydrological research. The present study will conduct feature extraction on groundwater levels to identify the spatiotemporal characteristics of groundwater. A three-dimensional groundwater model (MODFLOW) is used to create artificial cases that make sure the results will conform to the physical laws. By tuning parameters in model, the extracted features can show natural and anthropogenic disturbances under different scenarios. The data-driven analysis can effectively reveal insights of interactions between important variables of groundwater system. With a better view of spatiotemporal groundwater variations, it is useful for governmental agency to manage water resources.

  11. A SPATIOTEMPORAL APPROACH FOR HIGH RESOLUTION TRAFFIC FLOW IMPUTATION

    Energy Technology Data Exchange (ETDEWEB)

    Han, Lee [University of Tennessee, Knoxville (UTK); Chin, Shih-Miao [ORNL; Hwang, Ho-Ling [ORNL

    2016-01-01

    Along with the rapid development of Intelligent Transportation Systems (ITS), traffic data collection technologies have been evolving dramatically. The emergence of innovative data collection technologies such as Remote Traffic Microwave Sensor (RTMS), Bluetooth sensor, GPS-based Floating Car method, automated license plate recognition (ALPR) (1), etc., creates an explosion of traffic data, which brings transportation engineering into the new era of Big Data. However, despite the advance of technologies, the missing data issue is still inevitable and has posed great challenges for research such as traffic forecasting, real-time incident detection and management, dynamic route guidance, and massive evacuation optimization, because the degree of success of these endeavors depends on the timely availability of relatively complete and reasonably accurate traffic data. A thorough literature review suggests most current imputation models, if not all, focus largely on the temporal nature of the traffic data and fail to consider the fact that traffic stream characteristics at a certain location are closely related to those at neighboring locations and utilize these correlations for data imputation. To this end, this paper presents a Kriging based spatiotemporal data imputation approach that is able to fully utilize the spatiotemporal information underlying in traffic data. Imputation performance of the proposed approach was tested using simulated scenarios and achieved stable imputation accuracy. Moreover, the proposed Kriging imputation model is more flexible compared to current models.

  12. Unsupervised Discovery of Coherent Structures in Spatiotemporal Systems

    Science.gov (United States)

    Rupe, A.; Kashinath, K.; Prabhat, M.; Crutchfield, J. P.

    2016-12-01

    Coherent structures are ubiquitous in spatiotemporal systems far from equilibrium. These structures provide concise descriptions of the system and its dynamics, and there is often interest in these structures themselves. We present a novel method for automated detection and labeling of coherent structures that can be applied universally to spatiotemporal systems with local dynamics. Adapted from its original development in strictly temporal systems, computational mechanics is a method of inferring a hidden-state model from data which extracts and quantifies structure in the data. Significantly, the structures discovered by computational mechanics are not always readily identifiable from the raw data. Computational mechanics has been successfully applied to identify known structures in cellular automata. Here, we demonstrate the method on two-dimensional DNS hydrodynamic models of vortex shedding. Ultimately, we hope to analyze large-scale climate data for automated detection of extreme weather systems and other (possibly hidden) climatological structures. Current capabilities of the Computational Mechanics in Python (CMPy) software package allows for data parallelization using Berkeley Lab's Cori system, but significant scalability challenges remain to reach more realistic climate simulations. High-resolution simulations produce terabyte-size intermediates that require fully-distributed execution.

  13. Spatiotemporal variations of radar glacier zones in the Karakoram Mountains

    Science.gov (United States)

    Lund, Jewell

    2017-04-01

    Glaciers of the Karakoram Mountains are important climate indicators for densely populated South Central Asia. Glacial meltwater is a significant source of runoff in the Indus River Basin, upon which 60 million people rely for food security, economy and hydropower in Pakistan and India. Contrary to worldwide and also Himalayan trends, Karakoram glaciers have recently been verified in near balance, with some glaciers even gaining mass or surging. This 'Karakoram anomaly' is of interest, and many hypotheses exist for its causes. Complex climatology, coupled with the challenges of field study in this region, illicit notable uncertainties both in observation and prediction of glacial status. Constraining spatiotemporal variations in glacial mass balance will elucidate the extent and possible longevity of this anomaly, and its implications for water resources, as climate continues to change. Depending on snowpack conditions during image acquisition, different snow and ice zones on a glacier are identifiable in synthetic aperture radar (SAR) images. The identification and monitoring of radar glacier zones over time can provide indicators of relative glacial mass balance to compliment field studies in a region with sparse field measurement. We will present spatiotemporal evolution of basic radar glacier zones such as wet snow, bare ice, percolation, and firn for glaciers feeding into the Upper Indus Basin. We will incorporate both ascending and descending passes of Sentinel-1 series C -band sensors, and possibly ALOS-2 PALSAR-2 L-band images. We may also explore the impacts of these variations on timing and intensity of runoff.

  14. Spatiotemporal Features for Asynchronous Event-based Data

    Directory of Open Access Journals (Sweden)

    Xavier eLagorce

    2015-02-01

    Full Text Available Bio-inspired asynchronous event-based vision sensors are currently introducing a paradigm shift in visual information processing. These new sensors rely on a stimulus-driven principle of light acquisition similar to biological retinas. They are event-driven and fully asynchronous, thereby reducing redundancy and encoding exact times of input signal changes, leading to a very precise temporal resolution. Approaches for higher-level computer vision often rely on the realiable detection of features in visual frames, but similar definitions of features for the novel dynamic and event-based visual input representation of silicon retinas have so far been lacking. This article addresses the problem of learning and recognizing features for event-based vision sensors, which capture properties of truly spatiotemporal volumes of sparse visual event information. A novel computational architecture for learning and encoding spatiotemporal features is introduced based on a set of predictive recurrent reservoir networks, competing via winner-take-all selection. Features are learned in an unsupervised manner from real-world input recorded with event-based vision sensors. It is shown that the networks in the architecture learn distinct and task-specific dynamic visual features, and can predict their trajectories over time.

  15. Mining Spatiotemporal Patterns of the Elder's Daily Movement

    Science.gov (United States)

    Chen, C. R.; Chen, C. F.; Liu, M. E.; Tsai, S. J.; Son, N. T.; Kinh, L. V.

    2016-06-01

    With rapid developments in wearable device technology, a vast amount of spatiotemporal data, such as people's movement and physical activities, are generated. Information derived from the data reveals important knowledge that can contribute a long-term care and psychological assessment of the elders' living condition especially in long-term care institutions. This study aims to develop a method to investigate the spatial-temporal movement patterns of the elders with their outdoor trajectory information. To achieve the goal, GPS based location data of the elderly subjects from long-term care institutions are collected and analysed with geographic information system (GIS). A GIS statistical model is developed to mine the elderly subjects' spatiotemporal patterns with the location data and represent their daily movement pattern at particular time. The proposed method first finds the meaningful trajectory and extracts the frequent patterns from the time-stamp location data. Then, a density-based clustering method is used to identify the major moving range and the gather/stay hotspot in both spatial and temporal dimensions. The preliminary results indicate that the major moving area of the elderly people encompasses their dorm and has a short moving distance who often stay in the same site. Subjects' outdoor appearance are corresponded to their life routine. The results can be useful for understanding elders' social network construction, risky area identification and medical care monitoring.

  16. BICAR: A New Algorithm for Multiresolution Spatiotemporal Data Fusion

    Science.gov (United States)

    Brown, Kevin S.; Grafton, Scott T.; Carlson, Jean M.

    2012-01-01

    We introduce a method for spatiotemporal data fusion and demonstrate its performance on three constructed data sets: one entirely simulated, one with temporal speech signals and simulated spatial images, and another with recorded music time series and astronomical images defining the spatial patterns. Each case study is constructed to present specific challenges to test the method and demonstrate its capabilities. Our algorithm, BICAR (Bidirectional Independent Component Averaged Representation), is based on independent component analysis (ICA) and extracts pairs of temporal and spatial sources from two data matrices with arbitrarily different spatiotemporal resolution. We pair the temporal and spatial sources using a physical transfer function that connects the dynamics of the two. BICAR produces a hierarchy of sources ranked according to reproducibility; we show that sources which are more reproducible are more similar to true (known) sources. BICAR is robust to added noise, even in a “worst case” scenario where all physical sources are equally noisy. BICAR is also relatively robust to misspecification of the transfer function. BICAR holds promise as a useful data-driven assimilation method in neuroscience, earth science, astronomy, and other signal processing domains. PMID:23209693

  17. BICAR: a new algorithm for multiresolution spatiotemporal data fusion.

    Directory of Open Access Journals (Sweden)

    Kevin S Brown

    Full Text Available We introduce a method for spatiotemporal data fusion and demonstrate its performance on three constructed data sets: one entirely simulated, one with temporal speech signals and simulated spatial images, and another with recorded music time series and astronomical images defining the spatial patterns. Each case study is constructed to present specific challenges to test the method and demonstrate its capabilities. Our algorithm, BICAR (Bidirectional Independent Component Averaged Representation, is based on independent component analysis (ICA and extracts pairs of temporal and spatial sources from two data matrices with arbitrarily different spatiotemporal resolution. We pair the temporal and spatial sources using a physical transfer function that connects the dynamics of the two. BICAR produces a hierarchy of sources ranked according to reproducibility; we show that sources which are more reproducible are more similar to true (known sources. BICAR is robust to added noise, even in a "worst case" scenario where all physical sources are equally noisy. BICAR is also relatively robust to misspecification of the transfer function. BICAR holds promise as a useful data-driven assimilation method in neuroscience, earth science, astronomy, and other signal processing domains.

  18. Interpolation of daily rainfall using spatiotemporal models and clustering

    KAUST Repository

    Militino, A. F.

    2014-06-11

    Accumulated daily rainfall in non-observed locations on a particular day is frequently required as input to decision-making tools in precision agriculture or for hydrological or meteorological studies. Various solutions and estimation procedures have been proposed in the literature depending on the auxiliary information and the availability of data, but most such solutions are oriented to interpolating spatial data without incorporating temporal dependence. When data are available in space and time, spatiotemporal models usually provide better solutions. Here, we analyse the performance of three spatiotemporal models fitted to the whole sampled set and to clusters within the sampled set. The data consists of daily observations collected from 87 manual rainfall gauges from 1990 to 2010 in Navarre, Spain. The accuracy and precision of the interpolated data are compared with real data from 33 automated rainfall gauges in the same region, but placed in different locations than the manual rainfall gauges. Root mean squared error by months and by year are also provided. To illustrate these models, we also map interpolated daily precipitations and standard errors on a 1km2 grid in the whole region. © 2014 Royal Meteorological Society.

  19. Prediction of Suspect Location Based on Spatiotemporal Semantics

    Directory of Open Access Journals (Sweden)

    Lian Duan

    2017-06-01

    Full Text Available The prediction of suspect location enables proactive experiences for crime investigations and offers essential intelligence for crime prevention. However, existing studies have failed to capture the complex social location transition patterns of suspects and lack the capacity to address the issue of data sparsity. This paper proposes a novel location prediction model called CMoB (Crime Multi-order Bayes model based on the spatiotemporal semantics to enhance the prediction performance. In particular, the model groups suspects with similar spatiotemporal semantics as one target suspect. Then, their mobility data are applied to estimate Markov transition probabilities of unobserved locations based on a KDE (kernel density estimating smoothing method. Finally, by integrating the total transition probabilities, which are derived from the multi-order property of the Markov transition matrix, into a Bayesian-based formula, it is able to realize multi-step location prediction for the individual suspect. Experiments with the mobility dataset covering 210 suspects and their 18,754 location records from January to June 2012 in Wuhan City show that the proposed CMoB model significantly outperforms state-of-the-art algorithms for suspect location prediction in the context of data sparsity.

  20. Differential Effects of Alcohol Consumption Behaviours on Working Memory Processes

    OpenAIRE

    Shaunak Sanjay Deshpande

    2015-01-01

    Alcohol exposure in a clinical population impairs working memory. In order to establish the effects of alcohol on working memory in typical young adults, this study looked at their alcohol consumption behaviours and how they predict working memory. A battery of cognitive tasks and a recreational drug use questionnaire assessed working memory and alcohol consumption of 100 participants. The results revealed that alcohol abstinence predicted set-shifting, verbal executive, phonological loop, sp...

  1. Full-Scale Approximations of Spatio-Temporal Covariance Models for Large Datasets

    KAUST Repository

    Zhang, Bohai

    2014-01-01

    Various continuously-indexed spatio-temporal process models have been constructed to characterize spatio-temporal dependence structures, but the computational complexity for model fitting and predictions grows in a cubic order with the size of dataset and application of such models is not feasible for large datasets. This article extends the full-scale approximation (FSA) approach by Sang and Huang (2012) to the spatio-temporal context to reduce computational complexity. A reversible jump Markov chain Monte Carlo (RJMCMC) algorithm is proposed to select knots automatically from a discrete set of spatio-temporal points. Our approach is applicable to nonseparable and nonstationary spatio-temporal covariance models. We illustrate the effectiveness of our method through simulation experiments and application to an ozone measurement dataset.

  2. Study on quantile estimates of extreme precipitation and their spatiotemporal consistency adjustment over the Huaihe River basin

    Science.gov (United States)

    Shao, Yuehong; Wu, Junmei; Li, Min

    2017-01-01

    The quantile estimates and spatiotemporal consistency of extreme precipitation are studied by regional linear frequency analysis for Huaihe River basin in China. Firstly, the study area can be categorized into six homogeneous regions by using cluster analysis, heterogeneity measure, and discordancy measure. In the next step, we determine the optimum distribution for each homogeneous region by using two criteria of Monte Carlo simulations and the root-mean-square error (RMSE) of the sample L-moments. A diagram of L-moments ratio is used to further judge and validate the optimum distribution. The generalized extreme value (GEV), generalized normal (GNO), and generalized logistic (GLO) for 24-h duration are determined to be the more appropriate distribution based on the two criteria, L-moments ratio plot, and the tail thickness of curve in adjacent regions. A summary assessment can provide the more reasonable distribution, which avoids arbitrary results from single test. An important practical element of this study that was missing from previous works is the quantile spatiotemporal consistency analysis, which helps identify non-monotonicity among quantiles at different durations and reduces the gradient of estimates in the adjacent regions. Abnormality and spatial discontinuation can be removed by distributing the surplus of the ratio and twice different interpolation. A complete set of spatiotemporal consistent quantile estimates for various duration (24 h, 3 days, 5 days, and 7 days) and return periods (from 2 to 1000 years) can be obtained by using the abovementioned method in the study area, which are in the agreement with the observed precipitation extremes. It will provide important basis for hydrometeorological research, which is of significant scientific and practical merit.

  3. From distributed resources to limited slots in multiple-item working memory: a spiking network model with normalization

    National Research Council Canada - National Science Library

    Wei, Ziqiang; Wang, Xiao-Jing; Wang, Da-Hui

    2012-01-01

    ...: a "discrete-slot" model in which memory items are stored in a limited number of slots, and a "shared-resource" model in which the neural representation of items is distributed across a limited pool of resources...

  4. A spatio-temporal analysis of suicide in El Salvador

    Directory of Open Access Journals (Sweden)

    Carlos Carcach

    2017-04-01

    Full Text Available Abstract Background In 2012, international statistics showed El Salvador’s suicide rate as 40th in the world and the highest in Latin America. Over the last 15 years, national statistics show the suicide death rate declining as opposed to an increasing rate of homicide. Though completed suicide is an important social and health issue, little is known about its prevalence, incidence, etiology and spatio-temporal behavior. The primary objective of this study was to examine completed suicide and homicide using the stream analogy to lethal violence within a spatio-temporal framework. Methods A Bayesian model was applied to examine the spatio-temporal evolution of the tendency of completed suicide over homicide in El Salvador. Data on numbers of suicides and homicides at the municipal level were obtained from the Instituto de Medicina Legal (IML and population counts, from the Dirección General de Estadística y Censos (DIGESTYC, for the period of 2002 to 2012. Data on migration were derived from the 2007 Population Census, and inequality data were obtained from a study by Damianović, Valenzuela and Vera. Results The data reveal a stable standardized rate of total lethal violence (completed suicide plus homicide across municipalities over time; a decline in suicide; and a standardized suicide rate decreasing with income inequality but increasing with social isolation. Municipalities clustered in terms of both total lethal violence and suicide standardized rates. Conclusions Spatial effects for suicide were stronger among municipalities located in the north-east and center-south sides of the country. New clusters of municipalities with large suicide standardized rates were detected in the north-west, south-west and center-south regions, all of which are part of time-stable clusters of homicide. Prevention efforts to reduce income inequality and mitigate the negative effects of weak relational systems should focus upon municipalities forming time

  5. A spatio-temporal analysis of suicide in El Salvador.

    Science.gov (United States)

    Carcach, Carlos

    2017-04-20

    In 2012, international statistics showed El Salvador's suicide rate as 40th in the world and the highest in Latin America. Over the last 15 years, national statistics show the suicide death rate declining as opposed to an increasing rate of homicide. Though completed suicide is an important social and health issue, little is known about its prevalence, incidence, etiology and spatio-temporal behavior. The primary objective of this study was to examine completed suicide and homicide using the stream analogy to lethal violence within a spatio-temporal framework. A Bayesian model was applied to examine the spatio-temporal evolution of the tendency of completed suicide over homicide in El Salvador. Data on numbers of suicides and homicides at the municipal level were obtained from the Instituto de Medicina Legal (IML) and population counts, from the Dirección General de Estadística y Censos (DIGESTYC), for the period of 2002 to 2012. Data on migration were derived from the 2007 Population Census, and inequality data were obtained from a study by Damianović, Valenzuela and Vera. The data reveal a stable standardized rate of total lethal violence (completed suicide plus homicide) across municipalities over time; a decline in suicide; and a standardized suicide rate decreasing with income inequality but increasing with social isolation. Municipalities clustered in terms of both total lethal violence and suicide standardized rates. Spatial effects for suicide were stronger among municipalities located in the north-east and center-south sides of the country. New clusters of municipalities with large suicide standardized rates were detected in the north-west, south-west and center-south regions, all of which are part of time-stable clusters of homicide. Prevention efforts to reduce income inequality and mitigate the negative effects of weak relational systems should focus upon municipalities forming time-persistent clusters with a large rate of death by suicide. In

  6. Cartography in the Age of Spatio-temporal Big Data

    Directory of Open Access Journals (Sweden)

    WANG Jiayao

    2017-10-01

    Full Text Available Cartography is an ancient science with almost the same long history as the world's oldest culture.Since ancient times,the movement and change of anything and any phenomena,including human activities,have been carried out in a certain time and space.The development of science and technology and the progress of social civilization have made social management and governance more and more dependent on time and space.The information source,theme,content,carrier,form,production methods and application methods of map are different in different historical periods,so that its all-round value is different. With the arrival of the big data age,the scientific paradigm has now entered the era of "data-intensive" paradigm,so is the cartography,with obvious characteristics of big data science.All big data are caused by movement and change of all things and phenomena in the geographic world,so they have space and time characteristics and thus cannot be separated from the spatial reference and time reference.Therefore,big data is big spatio-temporal data essentially.Since the late 1950s and early 1960s,modern cartography,that is,the cartography in the information age,takes spatio-temporal data as the object,and focuses on the processing and expression of spatio-temporal data,but not in the face of the large scale multi-source heterogeneous and multi-dimensional dynamic data flow(or flow datafrom sky to the sea.The real-time dynamic nature,the theme pertinence,the content complexity,the carrier diversification,the expression form personalization,the production method modernization,the application ubiquity of the map,is incomparable in the past period,which leads to the great changes of the theory,technology and application system of cartography.And all these changes happen to occur in the 60 years since the late 1950s and early 1960s,so this article was written to commemorate the 60th anniversary of the "Acta Geodaetica et Cartographica Sinica".

  7. GIS Modeling of Solar Neighborhood Potential at a Fine Spatiotemporal Resolution

    Directory of Open Access Journals (Sweden)

    Annie Chow

    2014-05-01

    Full Text Available This research presents a 3D geographic information systems (GIS modeling approach at a fine spatiotemporal resolution to assess solar potential for the development of smart net-zero energy communities. It is important to be able to accurately identify the key areas on the facades and rooftops of buildings that receive maximum solar radiation, in order to prevent losses in solar gain due to obstructions from surrounding buildings and topographic features. A model was created in ArcGIS, in order to efficiently compute and iterate the hourly solar modeling and mapping process over a simulated year. The methodology was tested on a case study area located in southern Ontario, where two different 3D models of the site plan were analyzed. The accuracy of the work depends on the resolution and sky size of the input model. Future work is needed in order to create an efficient iterative function to speed the extraction process of the pixelated solar radiation data.

  8. Compressing an Ensemble with Statistical Models: An Algorithm for Global 3D Spatio-Temporal Temperature

    KAUST Repository

    Castruccio, Stefano

    2015-04-02

    One of the main challenges when working with modern climate model ensembles is the increasingly larger size of the data produced, and the consequent difficulty in storing large amounts of spatio-temporally resolved information. Many compression algorithms can be used to mitigate this problem, but since they are designed to compress generic scientific data sets, they do not account for the nature of climate model output and they compress only individual simulations. In this work, we propose a different, statistics-based approach that explicitly accounts for the space-time dependence of the data for annual global three-dimensional temperature fields in an initial condition ensemble. The set of estimated parameters is small (compared to the data size) and can be regarded as a summary of the essential structure of the ensemble output; therefore, it can be used to instantaneously reproduce the temperature fields in an ensemble with a substantial saving in storage and time. The statistical model exploits the gridded geometry of the data and parallelization across processors. It is therefore computationally convenient and allows to fit a non-trivial model to a data set of one billion data points with a covariance matrix comprising of 10^18 entries.

  9. Active processing of spatio-temporal input patterns in silicon dendrites.

    Science.gov (United States)

    Wang, Yingxue; Liu, Shih-Chii

    2013-06-01

    Capturing the functionality of active dendritic processing into abstract mathematical models will help us to understand the role of complex biophysical neurons in neuronal computation and to build future useful neuromorphic analog Very Large Scale Integrated (aVLSI) neuronal devices. Previous work based on an aVLSI multi-compartmental neuron model demonstrates that the compartmental response in the presence of either of two widely studied classes of active mechanisms, is a nonlinear sigmoidal function of the degree of either input temporal synchrony OR input clustering level. Using the same silicon model, this work expounds the interaction between both active mechanisms in a compartment receiving input patterns of varying temporal AND spatial clustering structure and demonstrates that this compartmental response can be captured by a combined sigmoid and radial-basis function over both input dimensions. This paper further shows that the response to input spatio-temporal patterns in a one-dimensional multi-compartmental dendrite, can be described by a radial-basis like function of the degree of temporal synchrony between the inter-compartmental inputs.

  10. Neural speech recognition: continuous phoneme decoding using spatiotemporal representations of human cortical activity

    Science.gov (United States)

    Moses, David A.; Mesgarani, Nima; Leonard, Matthew K.; Chang, Edward F.

    2016-10-01

    Objective. The superior temporal gyrus (STG) and neighboring brain regions play a key role in human language processing. Previous studies have attempted to reconstruct speech information from brain activity in the STG, but few of them incorporate the probabilistic framework and engineering methodology used in modern speech recognition systems. In this work, we describe the initial efforts toward the design of a neural speech recognition (NSR) system that performs continuous phoneme recognition on English stimuli with arbitrary vocabulary sizes using the high gamma band power of local field potentials in the STG and neighboring cortical areas obtained via electrocorticography. Approach. The system implements a Viterbi decoder that incorporates phoneme likelihood estimates from a linear discriminant analysis model and transition probabilities from an n-gram phonemic language model. Grid searches were used in an attempt to determine optimal parameterizations of the feature vectors and Viterbi decoder. Main results. The performance of the system was significantly improved by using spatiotemporal representations of the neural activity (as opposed to purely spatial representations) and by including language modeling and Viterbi decoding in the NSR system. Significance. These results emphasize the importance of modeling the temporal dynamics of neural responses when analyzing their variations with respect to varying stimuli and demonstrate that speech recognition techniques can be successfully leveraged when decoding speech from neural signals. Guided by the results detailed in this work, further development of the NSR system could have applications in the fields of automatic speech recognition and neural prosthetics.

  11. Approximate Bayesian computation methods for daily spatiotemporal precipitation occurrence simulation

    Science.gov (United States)

    Olson, Branden; Kleiber, William

    2017-04-01

    Stochastic precipitation generators (SPGs) produce synthetic precipitation data and are frequently used to generate inputs for physical models throughout many scientific disciplines. Especially for large data sets, statistical parameter estimation is difficult due to the high dimensionality of the likelihood function. We propose techniques to estimate SPG parameters for spatiotemporal precipitation occurrence based on an emerging set of methods called Approximate Bayesian computation (ABC), which bypass the evaluation of a likelihood function. Our statistical model employs a thresholded Gaussian process that reduces to a probit regression at single sites. We identify appropriate ABC penalization metrics for our model parameters to produce simulations whose statistical characteristics closely resemble those of the observations. Spell length metrics are appropriate for single sites, while a variogram-based metric is proposed for spatial simulations. We present numerical case studies at sites in Colorado and Iowa where the estimated statistical model adequately reproduces local and domain statistics.

  12. Spatiotemporal patterns of infant bronchiolitis in a Tennessee Medicaid population.

    Science.gov (United States)

    Sloan, Chantel D; Gebretsadik, Tebeb; Wu, Pingsheng; Carroll, Kecia N; Mitchel, Edward F; Hartert, Tina V

    2013-09-01

    Respiratory syncytial virus (RSV) is a major cause of worldwide morbidity and mortality in infants, primarily through the induction of bronchiolitis. RSV epidemics are highly seasonal, occurring in the winter months in the northern hemisphere. Within the United States, RSV epidemic dynamics vary both spatially and temporally. This analysis employs a retrospective space–time scan statistic to locate spatiotemporal clustering of infant bronchiolitis in a very large Tennessee (TN) Medicaid cohort. We studied infants less than 6 months of age (N = 52,468 infants) who had an outpatient visit, emergency department visit, or hospitalization for bronchiolitis between 1995 and 2008. The scan statistic revealed distinctive and consistent patterns of deviation in epidemic timing. Eastern TN (Knoxville area) showed clustering in January and February, and Central TN (Nashville area) in November and December. This is likely due to local variation in geography-associated factors which should be taken into consideration in future modeling of RSV epidemics.

  13. Parametric spatiotemporal oscillation in reaction-diffusion systems.

    Science.gov (United States)

    Ghosh, Shyamolina; Ray, Deb Shankar

    2016-03-01

    We consider a reaction-diffusion system in a homogeneous stable steady state. On perturbation by a time-dependent sinusoidal forcing of a suitable scaling parameter the system exhibits parametric spatiotemporal instability beyond a critical threshold frequency. We have formulated a general scheme to calculate the threshold condition for oscillation and the range of unstable spatial modes lying within a V-shaped region reminiscent of Arnold's tongue. Full numerical simulations show that depending on the specificity of nonlinearity of the models, the instability may result in time-periodic stationary patterns in the form of standing clusters or spatially localized breathing patterns with characteristic wavelengths. Our theoretical analysis of the parametric oscillation in reaction-diffusion system is corroborated by full numerical simulation of two well-known chemical dynamical models: chlorite-iodine-malonic acid and Briggs-Rauscher reactions.

  14. Spatiotemporal reconstruction of list-mode PET data

    CERN Document Server

    Nichols, T E; Asma, E; Leahy, R M

    2002-01-01

    We describe a method for computing a continuous time estimate of tracer density using list-mode positron emission tomography data. The rate function in each voxel is modeled as an inhomogeneous Poisson process whose rate function can be represented using a cubic B-spline basis. The rate functions are estimated by maximizing the likelihood of the arrival times of detected photon pairs over the control vertices of the spline, modified by quadratic spatial and temporal smoothness penalties and a penalty term to enforce non-negativity. Randoms rate functions are estimated by assuming independence between the spatial and temporal randoms distributions. Similarly, scatter rate functions are estimated by assuming spatiotemporal independence and that the temporal distribution of the scatter is proportional to the temporal distribution of the trues. A quantitative evaluation was performed using simulated data and the method is also demonstrated in a human study using 11C-raclopride.

  15. Spatiotemporal Patterns in Ultraslow Domain Wall Creep Dynamics.

    Science.gov (United States)

    Ferrero, Ezequiel E; Foini, Laura; Giamarchi, Thierry; Kolton, Alejandro B; Rosso, Alberto

    2017-04-07

    In the presence of impurities, ferromagnetic and ferroelectric domain walls slide only above a finite external field. Close to this depinning threshold, they proceed by large and abrupt jumps called avalanches, while, at much smaller fields, these interfaces creep by thermal activation. In this Letter, we develop a novel numerical technique that captures the ultraslow creep regime over huge time scales. We point out the existence of activated events that involve collective reorganizations similar to avalanches, but, at variance with them, display correlated spatiotemporal patterns that resemble the complex sequence of aftershocks observed after a large earthquake. Remarkably, we show that events assemble in independent clusters that display at large scales the same statistics as critical depinning avalanches. We foresee these correlated dynamics being experimentally accessible by magnetooptical imaging of ferromagnetic films.

  16. Patterning Biomaterials for the Spatiotemporal Delivery of Bioactive Molecules

    Science.gov (United States)

    Minardi, Silvia; Taraballi, Francesca; Pandolfi, Laura; Tasciotti, Ennio

    2016-01-01

    The aim of tissue engineering is to promote the repair of functional tissues. For decades, the combined use of biomaterials, growth factors (GFs), and stem cells has been the base of several regeneration strategies. Among these, biomimicry emerged as a robust strategy to efficiently address this clinical challenge. Biomimetic materials, able to recapitulate the composition and architecture of the extracellular matrix, are the materials of choice, for their biocompatibility and higher rate of efficacy. In addition, it has become increasingly clear that restoring the complex biochemical environment of the target tissue is crucial for its regeneration. Toward this aim, the combination of scaffolds and GFs is required. The advent of nanotechnology significantly impacted the field of tissue engineering by providing new ways to reproduce the complex spatial and temporal biochemical patterns of tissues. This review will present the most recent approaches to finely control the spatiotemporal release of bioactive molecules for various tissue engineering applications. PMID:27313997

  17. Patterning biomaterials for the spatiotemporal delivery of bioactive molecules

    Directory of Open Access Journals (Sweden)

    Silvia eMinardi

    2016-06-01

    Full Text Available The aim of tissue engineering is to promote the repair of functional tissues. For decades, the combined use of biomaterials, growth factors, and stem cells has been at the base of several regeneration strategies. Among these, biomimicry emerged as a robust strategy to efficiently address this clinical challenge. Biomimetic materials, able to recapitulate the composition and architecture of the extracellular matrix, are the materials of choice, for their biocompatibility and higher rate of efficacy. In addition, it has become increasingly clear that restoring the complex biochemical environment of the target tissue is crucial for its regeneration. Towards this aim, the combination of scaffolds and growth factors is required. The advent of nanotechnology significantly impacted the field of tissue engineering by providing new ways to reproduce the complex spatial and temporal biochemical patterns of tissues. This review will present the most recent approaches to finely control the spatiotemporal release of bioactive molecules for various tissue engineering applications.

  18. Spatiotemporal mode-locking in multimode fiber lasers

    Science.gov (United States)

    Wright, Logan G.; Christodoulides, Demetrios N.; Wise, Frank W.

    2017-10-01

    A laser is based on the electromagnetic modes of its resonator, which provides the feedback required for oscillation. Enormous progress has been made toward controlling the interactions of longitudinal modes in lasers with a single transverse mode. For example, the field of ultrafast science has been built on lasers that lock many longitudinal modes together to form ultrashort light pulses. However, coherent superposition of longitudinal and transverse modes in a laser has received little attention. We show that modal and chromatic dispersions in fiber lasers can be counteracted by strong spatial and spectral filtering. This allows locking of multiple transverse and longitudinal modes to create ultrashort pulses with a variety of spatiotemporal profiles. Multimode fiber lasers thus open new directions in studies of nonlinear wave propagation and capabilities for applications.

  19. Spatiotemporal reconstruction of list-mode PET data

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, Thomas E.; Qi, Jinyi; Asma, Evren; Leahy, Richard M.

    2002-03-01

    We describe a method for computing a continuous time estimate of tracer density using list-mode positron emission tomography data. The rate function in each voxel is modeled as an inhomogeneous Poisson process whose rate function can be represented using a cubic B-spline basis. The rate functions are estimated by maximizing the likelihood of the arrival times of detected photon pairs over the control vertices of the spline, modified by quadratic spatial and temporal smoothness penalties and a penalty term to enforce nonnegativity. Randoms rate functions are estimated by assuming independence between the spatial and temporal randoms distributions. Similarly, scatter rate functions are estimated by assuming spatiotemporal independence and that the temporal distribution of the scatter is proportional to the temporal distribution of the trues. A quantitative evaluation was performed using simulated data and the method is also demonstrated in a human study using 11C-raclopride.

  20. Entropy quantification of human brain spatio-temporal dynamics

    Science.gov (United States)

    Pezard, Laurent; Martinerie, Jacques; Müller-Gerking, Johannes; Varela, Francisco J.; Renault, Bernard

    We present a procedure to quantify spatio-temporal dynamics applied here to brain surface recordings during three distinct cognitive tasks. The method uses 19 sites of EEG recording as spatial embedding for the reconstruction of trajectories, global and local linear indices, and non-linear forecasting methods to quantify the global and local information loss of the dynamics (K-entropy). We show that K-entropy can differentiate between raw and multivariate phase random surrogate data in a significant percentage of EEG segments, and that relevant non-linear indices are best studied in time segments not longer than 4s. We also find a certain complementarity between local non-linear and linear indices for the discrimination between the three cognitive tasks. Moreover, localized projections onto electrode site of K-entropy provide a new kind of brain mapping with functional significance.

  1. BUILDING SPATIOTEMPORAL CLOUD PLATFORM FOR SUPPORTING GIS APPLICATION

    Directory of Open Access Journals (Sweden)

    W. W. Song

    2015-07-01

    Full Text Available Traditional geospatial information platforms are built, managed and maintained by the geoinformation agencies. They integrate various geospatial data (such as DLG, DOM, DEM, gazetteers, and thematic data to provide data analysis services for supporting government decision making. In the era of big data, it is challenging to address the data- and computing- intensive issues by traditional platforms. In this research, we propose to build a spatiotemporal cloud platform, which uses HDFS for managing image data, and MapReduce-based computing service and workflow for high performance geospatial analysis, as well as optimizing auto-scaling algorithms for Web client users’ quick access and visualization. Finally, we demonstrate the feasibility by several GIS application cases.

  2. Factor copula models for data with spatio-temporal dependence

    KAUST Repository

    Krupskii, Pavel

    2017-10-13

    We propose a new copula model for spatial data that are observed repeatedly in time. The model is based on the assumption that there exists a common factor that affects the measurements of a process in space and in time. Unlike models based on multivariate normality, our model can handle data with tail dependence and asymmetry. The likelihood for the proposed model can be obtained in a simple form and therefore parameter estimation is quite fast. Simulation from this model is straightforward and data can be predicted at any spatial location and time point. We use simulation studies to show different types of dependencies, both in space and in time, that can be generated by this model. We apply the proposed copula model to hourly wind data and compare its performance with some classical models for spatio-temporal data.

  3. Spatio-temporal joins on symbolic indoor tracking data

    DEFF Research Database (Denmark)

    Lu, Hua; Yang, Bin; Jensen, Christian S.

    2011-01-01

    To facilitate a variety of applications, positioning systems are deployed in indoor settings. For example, Bluetooth and RFID positioning are deployed in airports to support real-time monitoring of delays as well as off-line flow and space usage analyses. Such deployments generate large collections...... of tracking data. Like in other data management applications, joins are indispensable in this setting. However, joins on indoor tracking data call for novel techniques that take into account the limited capabilities of the positioning systems as well as the specifics of indoor spaces. This paper proposes...... and studies probabilistic, spatio-temporal joins on historical indoor tracking data. Two meaningful types of join are defined. They return object pairs that satisfy spatial join predicates either at a time point or during a time interval. The predicates considered include “same X,” where X is a semantic...

  4. Building Spatiotemporal Cloud Platform for Supporting GIS Application

    Science.gov (United States)

    Song, W. W.; Jin, B. X.; Li, S. H.; Wei, X. Y.; Li, D.; Hu, F.

    2015-07-01

    Traditional geospatial information platforms are built, managed and maintained by the geoinformation agencies. They integrate various geospatial data (such as DLG, DOM, DEM, gazetteers, and thematic data) to provide data analysis services for supporting government decision making. In the era of big data, it is challenging to address the data- and computing- intensive issues by traditional platforms. In this research, we propose to build a spatiotemporal cloud platform, which uses HDFS for managing image data, and MapReduce-based computing service and workflow for high performance geospatial analysis, as well as optimizing auto-scaling algorithms for Web client users' quick access and visualization. Finally, we demonstrate the feasibility by several GIS application cases.

  5. Anchoring of FRET Sensors-A Requirement for Spatiotemporal Resolution.

    Science.gov (United States)

    Ivanova, Elena V; Figueroa, Ricardo A; Gatsinzi, Tom; Hallberg, Einar; Iverfeldt, Kerstin

    2016-05-16

    FRET biosensors have become a routine tool for investigating mechanisms and components of cell signaling. Strategies for improving them for particular applications are continuously sought. One important aspect to consider when designing FRET probes is the dynamic distribution and propagation of signals within living cells. We have addressed this issue by directly comparing an anchored (taFS) to a non-anchored (naFS) cleavable FRET sensor. We chose a microtubule-associated protein tau as an anchor, as microtubules are abundant throughout the cytosol of cells. We show that tau-anchored FRET sensors are concentrated at the cytoskeleton and enriched in the neurite-like processes of cells, providing high intensity of the total signal. In addition, anchoring limits the diffusion of the sensor, enabling spatiotemporally resolved monitoring of subcellular variations in enzyme activity. Thus, anchoring is an important aspect to consider when designing FRET sensors for deeper understanding of cell signaling.

  6. ESIPT-Based Photoactivatable Fluorescent Probe for Ratiometric Spatiotemporal Bioimaging

    Directory of Open Access Journals (Sweden)

    Xiaohong Zhou

    2016-10-01

    Full Text Available Photoactivatable fluorophores have become an important technique for the high spatiotemporal resolution of biological imaging. Here, we developed a novel photoactivatable probe (PHBT, which is based on 2-(2-hydroxyphenylbenzothiazole (HBT, a small organic fluorophore known for its classic luminescence mechanism through excited-state intramolecular proton transfer (ESIPT with the keto form and the enol form. After photocleavage, PHBT released a ratiometric fluorophore HBT, which showed dual emission bands with more than 73-fold fluorescence enhancement at 512 nm in buffer and more than 69-fold enhancement at 452 nm in bovine serum. The probe displayed a high ratiometric imaging resolution and is believed to have a wide application in biological imaging.

  7. Delay-driven irregular spatiotemporal patterns in a plankton system.

    Science.gov (United States)

    Tian, Canrong; Zhang, Lai

    2013-07-01

    An inhomogeneous distribution of species density over physical space is a widely observed scenario in plankton systems. Understanding the mechanisms resulting in these spatial patterns is a central topic in plankton ecology. In this paper we explore the impact of time delay on spatiotemporal patterns in a prey-predator plankton system. We find that time delay can trigger the emergence of irregular spatial patterns via a Hopf bifurcation. Moreover, a phase transition from a regular spiral pattern to an irregular one was observed and the latter gradually replaced the former and persisted indefinitely. The characteristic length of the emergent spatial pattern is consistent with the scale of plankton patterns observed in field studies.

  8. Spatio-temporal structure of hooded gull flocks.

    Science.gov (United States)

    Yomosa, Makoto; Mizuguchi, Tsuyoshi; Hayakawa, Yoshinori

    2013-01-01

    We analyzed the spatio-temporal structure of hooded gull flocks with a portable stereo camera system. The 3-dimensional positions of individuals were reconstructed from pairs of videos. The motions of each individual were analyzed, and both gliding and flapping motions were quantified based on the velocity time series. We analyzed the distributions of the nearest neighbor's position in terms of coordinates based on each individual's motion. The obtained results were consistent with the aerodynamic interaction between individuals. We characterized the leader-follower relationship between individuals by a delay time to mimic the direction of a motion. A relation between the delay time and a relative position was analyzed quantitatively, which suggested the basic properties of the formation flight that maintains order in the flock.

  9. Spatio-temporal structure of hooded gull flocks.

    Directory of Open Access Journals (Sweden)

    Makoto Yomosa

    Full Text Available We analyzed the spatio-temporal structure of hooded gull flocks with a portable stereo camera system. The 3-dimensional positions of individuals were reconstructed from pairs of videos. The motions of each individual were analyzed, and both gliding and flapping motions were quantified based on the velocity time series. We analyzed the distributions of the nearest neighbor's position in terms of coordinates based on each individual's motion. The obtained results were consistent with the aerodynamic interaction between individuals. We characterized the leader-follower relationship between individuals by a delay time to mimic the direction of a motion. A relation between the delay time and a relative position was analyzed quantitatively, which suggested the basic properties of the formation flight that maintains order in the flock.

  10. StatCast Dashboard: Exploration of Spatiotemporal Baseball Data.

    Science.gov (United States)

    Lage, Marcos; Ono, Jorge Piazentin; Cervone, Daniel; Chiang, Justin; Dietrich, Carlos; Silva, Claudio T

    2016-01-01

    Major League Baseball (MLB) has a long history of providing detailed, high-quality data, leading to a tremendous surge in sports analytics research in recent years. In 2015, MLB.com released the StatCast spatiotemporal data-tracking system, which has been used in approximately 2,500 games since its inception to capture player and ball locations as well as semantically meaningful game events. This article presents a visualization and analytics infrastructure to help query and facilitate the analysis of this new tracking data. The goal is to go beyond descriptive statistics of individual plays, allowing analysts to study diverse collections of games and game events. The proposed system enables the exploration of the data using a simple querying interface and a set of flexible interactive visualization tools.

  11. A Hybrid Spatio-Temporal Data Indexing Method for Trajectory Databases

    Directory of Open Access Journals (Sweden)

    Shengnan Ke

    2014-07-01

    Full Text Available In recent years, there has been tremendous growth in the field of indoor and outdoor positioning sensors continuously producing huge volumes of trajectory data that has been used in many fields such as location-based services or location intelligence. Trajectory data is massively increased and semantically complicated, which poses a great challenge on spatio-temporal data indexing. This paper proposes a spatio-temporal data indexing method, named HBSTR-tree, which is a hybrid index structure comprising spatio-temporal R-tree, B*-tree and Hash table. To improve the index generation efficiency, rather than directly inserting trajectory points, we group consecutive trajectory points as nodes according to their spatio-temporal semantics and then insert them into spatio-temporal R-tree as leaf nodes. Hash table is used to manage the latest leaf nodes to reduce the frequency of insertion. A new spatio-temporal interval criterion and a new node-choosing sub-algorithm are also proposed to optimize spatio-temporal R-tree structures. In addition, a B*-tree sub-index of leaf nodes is built to query the trajectories of targeted objects efficiently. Furthermore, a database storage scheme based on a NoSQL-type DBMS is also proposed for the purpose of cloud storage. Experimental results prove that HBSTR-tree outperforms TB*-tree in some aspects such as generation efficiency, query performance and query type.

  12. Spatiotemporal memory is an intrinsic property of networks of dissociated cortical neurons.

    Science.gov (United States)

    Ju, Han; Dranias, Mark R; Banumurthy, Gokulakrishna; VanDongen, Antonius M J

    2015-03-04

    The ability to process complex spatiotemporal information is a fundamental process underlying the behavior of all higher organisms. However, how the brain processes information in the temporal domain remains incompletely understood. We have explored the spatiotemporal information-processing capability of networks formed from dissociated rat E18 cortical neurons growing in culture. By combining optogenetics with microelectrode array recording, we show that these randomly organized cortical microcircuits are able to process complex spatiotemporal information, allowing the identification of a large number of temporal sequences and classification of musical styles. These experiments uncovered spatiotemporal memory processes lasting several seconds. Neural network simulations indicated that both short-term synaptic plasticity and recurrent connections are required for the emergence of this capability. Interestingly, NMDA receptor function is not a requisite for these short-term spatiotemporal memory processes. Indeed, blocking the NMDA receptor with the antagonist APV significantly improved the temporal processing ability of the networks, by reducing spontaneously occurring network bursts. These highly synchronized events have disastrous effects on spatiotemporal information processing, by transiently erasing short-term memory. These results show that the ability to process and integrate complex spatiotemporal information is an intrinsic property of generic cortical networks that does not require specifically designed circuits. Copyright © 2015 the authors 0270-6474/15/354040-12$15.00/0.

  13. A hybrid spatio-temporal data indexing method for trajectory databases.

    Science.gov (United States)

    Ke, Shengnan; Gong, Jun; Li, Songnian; Zhu, Qing; Liu, Xintao; Zhang, Yeting

    2014-07-21

    In recent years, there has been tremendous growth in the field of indoor and outdoor positioning sensors continuously producing huge volumes of trajectory data that has been used in many fields such as location-based services or location intelligence. Trajectory data is massively increased and semantically complicated, which poses a great challenge on spatio-temporal data indexing. This paper proposes a spatio-temporal data indexing method, named HBSTR-tree, which is a hybrid index structure comprising spatio-temporal R-tree, B*-tree and Hash table. To improve the index generation efficiency, rather than directly inserting trajectory points, we group consecutive trajectory points as nodes according to their spatio-temporal semantics and then insert them into spatio-temporal R-tree as leaf nodes. Hash table is used to manage the latest leaf nodes to reduce the frequency of insertion. A new spatio-temporal interval criterion and a new node-choosing sub-algorithm are also proposed to optimize spatio-temporal R-tree structures. In addition, a B*-tree sub-index of leaf nodes is built to query the trajectories of targeted objects efficiently. Furthermore, a database storage scheme based on a NoSQL-type DBMS is also proposed for the purpose of cloud storage. Experimental results prove that HBSTR-tree outperforms TB*-tree in some aspects such as generation efficiency, query performance and query type.

  14. A Hybrid Spatio-Temporal Data Indexing Method for Trajectory Databases

    Science.gov (United States)

    Ke, Shengnan; Gong, Jun; Li, Songnian; Zhu, Qing; Liu, Xintao; Zhang, Yeting

    2014-01-01

    In recent years, there has been tremendous growth in the field of indoor and outdoor positioning sensors continuously producing huge volumes of trajectory data that has been used in many fields such as location-based services or location intelligence. Trajectory data is massively increased and semantically complicated, which poses a great challenge on spatio-temporal data indexing. This paper proposes a spatio-temporal data indexing method, named HBSTR-tree, which is a hybrid index structure comprising spatio-temporal R-tree, B*-tree and Hash table. To improve the index generation efficiency, rather than directly inserting trajectory points, we group consecutive trajectory points as nodes according to their spatio-temporal semantics and then insert them into spatio-temporal R-tree as leaf nodes. Hash table is used to manage the latest leaf nodes to reduce the frequency of insertion. A new spatio-temporal interval criterion and a new node-choosing sub-algorithm are also proposed to optimize spatio-temporal R-tree structures. In addition, a B*-tree sub-index of leaf nodes is built to query the trajectories of targeted objects efficiently. Furthermore, a database storage scheme based on a NoSQL-type DBMS is also proposed for the purpose of cloud storage. Experimental results prove that HBSTR-tree outperforms TB*-tree in some aspects such as generation efficiency, query performance and query type. PMID:25051028

  15. Spatiotemporal volumetric analysis of dynamic plantar pressure data.

    Science.gov (United States)

    Pataky, Todd Colin; Maiwald, Christian

    2011-08-01

    The purposes of this study were (i) to develop a three-dimensional interactive visualization tool for exploring plantar pressure time series and spatiotemporal statistical volumes and (ii) to demonstrate the benefits of volumetric analyses using various running and walking data sets. A data exploration tool was developed in Python using the open-source Visualization Toolkit. Multiple-pressure isosurfaces were computed and were then rendered with interactive rotation and adjustable thresholds and transparencies. Plantar pressure data were collected: (i) from two running subjects, one with a heel-loading pattern and one with a forefoot-loading pattern; (ii) from one individual while running straight and then while performing a cutting maneuver; and (iii) from one subject walking at three different speeds. All data were spatiotemporally aligned, and mean volumes were computed. Statistical volumes were also computed for the walking data set, and significance was assessed topologically using techniques from three-dimensional brain imaging. After converting raw plantar pressure data into a rapidly readable format, volumetric renderings were presented in ∼50 ms, a negligible time lag for interactive data exploration. We observed that consideration of only spatial two-dimensional variables yielded "impulse illusions" that could be resolved most effectively with three-dimensional renderings. For all data sets, we found that dynamic foot behavior was clearest through interactive three-dimensional exploration. Plantar pressure data contain high-quality biomechanical information in their original three-dimensional form. The main benefit of the proposed visualization technique is that it affords qualitatively rich and unique holistic explorations of dynamic foot behavior.

  16. Long-term spatio-temporal drought variability in Turkey

    Science.gov (United States)

    Dabanlı, İsmail; Mishra, Ashok K.; Şen, Zekai

    2017-09-01

    The spatio-temporal variability of drought is presented by evaluating homogeneously distributed 250 station records from 1931 to 2010 for 80 years' duration in Turkey. The drought analysis is implemented using Standardized Precipitation Index (SPI) in terms of SPI-1, SPI-3, SPI-6, SPI-6AS (SPI-6 April to September) and SPI-12. The principle component analysis (PCA) is applied to SPI time series to identify spatial and temporal drought patterns. SPI time series are classified into two groups (1st group: SPI-1, SPI-3, SPI-6AS; and 2nd group: SPI-6 and SPI-12) according to the similarity in spatial drought patterns. SPI-3 and SPI-12 are selected as representative members of each group for spatio-temporal analysis. A relationship among correlation area (An), correlation coefficient (CC), principle component numbers (Fn) and total variances explained (Vexp) are investigated for identifying four well-defined drought vulnerable homogeneous regions over Turkey mainland. Mean percentages of extreme, severe, and moderate drought areas are calculated as 3.13% (2.81%), 3.75% (4.06%) and 7.19% (7.50%) for SPI-3 (SPI-12) based on 80 years in all drought vulnerable regions. Spectral characteristics of drought are also investigated based on fast Fourier transform (FFT) method. It is observed that while southeastern and western parts of Turkey are more stable due to the highly-correlated variances of spatial patterns; central parts and few pockets in northern areas of Turkey are less stable regions because of the low-correlated variance scores (below 10%). Furthermore, the impact of extreme phases of the ENSO (El Nino/La Nina) on droughts in four drought regions over Turkey is discussed.

  17. SPATIO-TEMPORAL COMPLEXITY OF THE AORTIC SINUS VORTEX.

    Science.gov (United States)

    Moore, Brandon; Dasi, Lakshmi Prasad

    2014-06-01

    The aortic sinus vortex is a classical flow structure of significant importance to aortic valve dynamics and the initiation and progression of calific aortic valve disease. We characterize the spatio-temporal characteristics of aortic sinus voxtex dynamics in relation to the viscosity of blood analog solution as well as heart rate. High resolution time-resolved (2KHz) particle image velocimetry was conducted to capture 2D particle streak videos and 2D instantaneous velocity and streamlines along the sinus midplane using a physiological but rigid aorta model fitted with a porcine bioprosthetic heart valve. Blood analog fluids used include a water-glycerin mixture and saline to elucidate the sensitivity of vortex dynamics to viscosity. Experiments were conducted to record 10 heart beats for each combination of blood analog and heart rate condition. Results show that the topological characteristics of the velocity field vary in time-scales as revealed using time bin averaged vectors and corresponding instantaneous streamlines. There exist small time-scale vortices and a large time-scale main vortex. A key flow structure observed is the counter vortex at the upstream end of the sinus adjacent to the base (lower half) of the leaflet. The spatio-temporal complexity of vortex dynamics is shown to be profoundly influenced by strong leaflet flutter during systole with a peak frequency of 200Hz and peak amplitude of 4 mm observed in the saline case. While fluid viscosity influences the length and time-scales as well as the introduction of leaflet flutter, heart rate influences the formation of counter vortex at the upstream end of the sinus. Higher heart rates are shown to reduce the strength of the counter vortex that can greatly influence the directionality and strength of shear stresses along the base of the leaflet. This study demonstrates the impact of heart rate and blood analog viscosity on aortic sinus hemodynamics.

  18. Climate-mediated spatiotemporal variability in terrestrial productivity across Europe

    Science.gov (United States)

    Wu, X.; Babst, F.; Ciais, P.; Frank, D.; Reichstein, M.; Wattenbach, M.; Zang, C.; Mahecha, M. D.

    2014-06-01

    Quantifying the interannual variability (IAV) of the terrestrial ecosystem productivity and its sensitivity to climate is crucial for improving carbon budget predictions. In this context it is necessary to disentangle the influence of climate from impacts of other mechanisms underlying the spatiotemporal patterns of IAV of the ecosystem productivity. In this study we investigated the spatiotemporal patterns of IAV of historical observations of European crop yields in tandem with a set of climate variables. We further evaluated if relevant remote-sensing retrievals of NDVI (normalized difference vegetation index) and FAPAR (fraction of absorbed photosynthetically active radiation) depict a similar behaviour. Our results reveal distinct spatial patterns in the IAV of the analysed proxies linked to terrestrial productivity. In particular, we find higher IAV in water-limited regions of Europe (Mediterranean and temperate continental Europe) compared to other regions in both crop yield and remote-sensing observations. Our results further indicate that variations in the water balance during the active growing season exert a more pronounced and direct effect than variations of temperature on explaining the spatial patterns in IAV of productivity-related variables in temperate Europe. Overall, we observe a temporally increasing trend in the IAV of terrestrial productivity and an increasing sensitivity of productivity to water availability in dry regions of Europe during the 1975-2009 period. In the same regions, a simultaneous increase in the IAV of water availability was detected. These findings suggest intricate responses of carbon fluxes to climate variability in Europe and that the IAV of terrestrial productivity has become potentially more sensitive to changes in water availability in the dry regions in Europe. The changing sensitivity of terrestrial productivity accompanied by the changing IAV of climate is expected to impact carbon stocks and the net carbon balance

  19. Spatiotemporal Coding of Individual Chemicals by the Gustatory System.

    Science.gov (United States)

    Reiter, Sam; Campillo Rodriguez, Chelsey; Sun, Kui; Stopfer, Mark

    2015-09-02

    Four of the five major sensory systems (vision, olfaction, somatosensation, and audition) are thought to use different but partially overlapping sets of neurons to form unique representations of vast numbers of stimuli. The only exception is gustation, which is thought to represent only small numbers of basic taste categories. However, using new methods for delivering tastant chemicals and making electrophysiological recordings from the tractable gustatory system of the moth Manduca sexta, we found chemical-specific information is as follows: (1) initially encoded in the population of gustatory receptor neurons as broadly distributed spatiotemporal patterns of activity; (2) dramatically integrated and temporally transformed as it propagates to monosynaptically connected second-order neurons; and (3) observed in tastant-specific behavior. Our results are consistent with an emerging view of the gustatory system: rather than constructing basic taste categories, it uses a spatiotemporal population code to generate unique neural representations of individual tastant chemicals. Our results provide a new view of taste processing. Using a new, relatively simple model system and a new set of techniques to deliver taste stimuli and to examine gustatory receptor neurons and their immediate followers, we found no evidence for labeled line connectivity, or basic taste categories such as sweet, salty, bitter, and sour. Rather, individual tastant chemicals are represented as patterns of spiking activity distributed across populations of receptor neurons. These representations are transformed substantially as multiple types of receptor neurons converge upon follower neurons, leading to a combinatorial coding format that uniquely, rapidly, and efficiently represents individual taste chemicals. Finally, we found that the information content of these neurons can drive tastant-specific behavior. Copyright © 2015 the authors 0270-6474/15/3512309-13$15.00/0.

  20. Spatiotemporal Analysis of AIDS Incidence Among Adults in Brazil.

    Science.gov (United States)

    da Silva Lizzi, Elisangela Aparecida; Nunes, Altacilio Aparecido; Martinez, Edson Zangiacomi

    2016-01-01

    AIDS is the fourth leading cause of death worldwide and, currently, the overall prevalence rate of HIV infection in Brazil is 0.5% among men and 0.3% among women. To evaluate the spatiotemporal trend of AIDS in Brazil from 2006 to 2012 and its relationship with human development index (HDI) and their components income, education and life expectancy. This ecological study evaluate the spatiotemporal trend of standardized incidence ratio of AIDS among adults in Brazil from 2006 to 2012 and its relationship with HDI by using a Bayesian analysis, considering the Brazilian Federal Units as units of analysis. The proposed statistical model allows obtaining a standardized incidence ratio (SIR, adjusted by gender and age). Among the men, our results show higher incidence rates in the States of the Southern regions as well as in the state of Amazonas (Northern Brazil). In females, we found other patterns for SIR, with higher incidence rates in the states of Rio de Janeiro (Southeast region), Rio Grande do Sul and Santa Catarina (both in Southern region). Among men it was observed as an expressive association between the SIR values and the overall HDI and income and education components, but it was observed to have an inverse association with the life expectancy component. Among women, it is noted that the SIR values are associated with the overall HDI and the education components only at the beginning of the studied period. AIDS remains a major public health problem in Brazil, mainly in the southern and southeastern regions of the country. Considering its association with HDI, it is noted that the disease still remains related to the pattern observed in the early years of the studied period, at least in the more developed regions of Brazil. This certainly happened because of the chronicity of the disease, thus affecting people with good socioeconomic status.

  1. Differences in Spatiotemporal Parameters Between Trained Runners and Untrained Participants.

    Science.gov (United States)

    Gómez-Molina, Josué; Ogueta-Alday, Ana; Stickley, Christopher; Cámara, Jesús; Cabrejas-Ugartondo, Jon; García-López, Juan

    2017-08-01

    Gómez-Molina, J, Ogueta-Alday, A, Stickley, C, Tobalina, JC, Cabrejas-Ugartondo, J, and García-López, J. Differences in spatiotemporal parameters between trained runners and untrained participants. J Strength Cond Res 31(8): 2169-2175, 2017-The aim of this study was to compare the spatiotemporal parameters of trained runners and untrained participants with the same foot strike pattern (rearfoot) during running at controlled speeds. Twenty-one participants were classified in 2 groups according to their training experience: Trained (n = 10, amateur runners with long distance training experience) and Untrained (n = 11, healthy untrained participants). Anthropometric variables were recorded, and the participants performed both a submaximal (between 9 and 15 km·h) and a graded exercise running test (from 6 km·h until exhaustion) on a treadmill. Physiological (V[Combining Dot Above]O2max, heart rate, running economy [RE], peak speed …) and biomechanical variables (contact and flight times, step rate, and length) were simultaneously registered. Trained runners showed higher step rate and shorter step length than the Untrained group at the same running speeds (between 4 and 7%, p ≤ 0.05) and at the same physiological intensities (between 7 and 11%, p ≤ 0.05). However, there were no differences in contact and flight times between groups. Significant differences (p ≤ 0.05) and large effect sizes (Cohen's d) between groups were found for body mass, sum of 6 skinfolds, V[Combining Dot Above]O2max, peak speed, and ventilatory threshold and respiratory compensation threshold speeds. The Trained group also showed a ∼7% better RE (ml·kg·km) than the Untrained group. In conclusion, adopting higher step rate and shorter step length may be an adaptive mechanism of the Trained group to reduce injury risk and possibly improve RE. However, contact and flight times were consistent regardless of training level.

  2. A spatio-temporal reference model of the aging brain.

    Science.gov (United States)

    Huizinga, W; Poot, D H J; Vernooij, M W; Roshchupkin, G V; Bron, E E; Ikram, M A; Rueckert, D; Niessen, W J; Klein, S

    2017-12-05

    Both normal aging and neurodegenerative disorders such as Alzheimer's disease (AD) cause morphological changes of the brain. It is generally difficult to distinguish these two causes of morphological change by visual inspection of magnetic resonance (MR) images. To facilitate making this distinction and thus aid the diagnosis of neurodegenerative disorders, we propose a method for developing a spatio-temporal model of morphological differences in the brain due to normal aging. The method utilizes groupwise image registration to characterize morphological variation across brain scans of people with different ages. To extract the deformations that are due to normal aging we use partial least squares regression, which yields modes of deformations highly correlated with age, and corresponding scores for each input subject. Subsequently, we determine a distribution of morphologies as a function of age by fitting smooth percentile curves to these scores. This distribution is used as a reference to which a person's morphology score can be compared. We validate our method on two different datasets, using images from both cognitively normal subjects and patients with Alzheimer disease (AD). Results show that the proposed framework extracts the expected atrophy patterns. Moreover, the morphology scores of cognitively normal subjects are on average lower than the scores of AD subjects, indicating that morphology differences between AD subjects and healthy subjects can be partly explained by accelerated aging. With our methods we are able to assess accelerated brain aging on both population and individual level. A spatio-temporal aging brain model derived from 988 T1-weighted MR brain scans from a large population imaging study (age range 45.9-91.7y, mean age 68.3y) is made publicly available at www.agingbrain.nl. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  3. Spatiotemporal study of elderly suicide in Korea by age cohort.

    Science.gov (United States)

    Joo, Y

    2017-01-01

    This study analyzed the spatiotemporal pattern and spatial diffusion of elderly suicide by age cohort, in Korea. The research investigated the elderly suicide rates of the 232 municipal units in South Korea between 2001 and 2011. The Gi* score, which is a spatially weighted indicator of area attributes, was used to identify hot spots and the spatiotemporal pattern of elderly suicide in the nation during the last 10 years. The spatial Markov matrix and spatial dynamic panel data model were employed to identify and estimate the diffusion effect. The suicide rate among elderly individuals 75 years and older was substantially higher than the rate for those between 65 and 74 years of age; however, the spatial patterns of the suicide clusters were similar between the two groups. From 2001 to 2011, the spatial distribution of elderly suicide hot spots differed each year. For both age cohorts, elderly suicide hot spots developed around the north area of South Korea in 2001 and moved to the mid-east area and the mid-western coastal area over 10 years. The spatial Markov matrix indicates that the change in the suicide rate of one area was affected by the suicide rates of neighbouring areas from the previous year, which suggests that suicide increase in one area inflates a neighbouring area's suicide rate over time. Using a spatial dynamic panel data model, elderly suicide diffusion effects were found to be statistically significant for both age cohorts even after economic and demographic indicators and a time variable are included. For individuals 75 years and older, the diffusion effect appeared to be larger. This study demonstrates that elderly suicide can spread spatially over time in both age cohorts. Thus, it is necessary to design a place-based and age-differentiated intervention policy that precisely considers the spatial diffusion of elderly suicide. Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  4. Patterns of urban violent injury: a spatio-temporal analysis.

    Directory of Open Access Journals (Sweden)

    Michael Cusimano

    2010-01-01

    Full Text Available Injury related to violent acts is a problem in every society. Although some authors have examined the geography of violent crime, few have focused on the spatio-temporal patterns of violent injury and none have used an ambulance dataset to explore the spatial characteristics of injury. The purpose of this study was to describe the combined spatial and temporal characteristics of violent injury in a large urban centre.Using a geomatics framework and geographic information systems software, we studied 4,587 ambulance dispatches and 10,693 emergency room admissions for violent injury occurrences among adults (aged 18-64 in Toronto, Canada, during 2002 and 2004, using population-based datasets. We created kernel density and choropleth maps for 24-hour periods and four-hour daily time periods and compared location of ambulance dispatches and patient residences with local land use and socioeconomic characteristics. We used multivariate regressions to control for confounding factors. We found the locations of violent injury and the residence locations of those injured were both closely related to each other and clearly clustered in certain parts of the city characterised by high numbers of bars, social housing units, and homeless shelters, as well as lower household incomes. The night and early morning showed a distinctive peak in injuries and a shift in the location of injuries to a "nightlife" district. The locational pattern of patient residences remained unchanged during those times.Our results demonstrate that there is a distinctive spatio-temporal pattern in violent injury reflected in the ambulance data. People injured in this urban centre more commonly live in areas of social deprivation. During the day, locations of injury and locations of residences are similar. However, later at night, the injury location of highest density shifts to a "nightlife" district, whereas the residence locations of those most at risk of injury do not change.

  5. Patterns of urban violent injury: a spatio-temporal analysis.

    Science.gov (United States)

    Cusimano, Michael; Marshall, Sean; Rinner, Claus; Jiang, Depeng; Chipman, Mary

    2010-01-13

    Injury related to violent acts is a problem in every society. Although some authors have examined the geography of violent crime, few have focused on the spatio-temporal patterns of violent injury and none have used an ambulance dataset to explore the spatial characteristics of injury. The purpose of this study was to describe the combined spatial and temporal characteristics of violent injury in a large urban centre. Using a geomatics framework and geographic information systems software, we studied 4,587 ambulance dispatches and 10,693 emergency room admissions for violent injury occurrences among adults (aged 18-64) in Toronto, Canada, during 2002 and 2004, using population-based datasets. We created kernel density and choropleth maps for 24-hour periods and four-hour daily time periods and compared location of ambulance dispatches and patient residences with local land use and socioeconomic characteristics. We used multivariate regressions to control for confounding factors. We found the locations of violent injury and the residence locations of those injured were both closely related to each other and clearly clustered in certain parts of the city characterised by high numbers of bars, social housing units, and homeless shelters, as well as lower household incomes. The night and early morning showed a distinctive peak in injuries and a shift in the location of injuries to a "nightlife" district. The locational pattern of patient residences remained unchanged during those times. Our results demonstrate that there is a distinctive spatio-temporal pattern in violent injury reflected in the ambulance data. People injured in this urban centre more commonly live in areas of social deprivation. During the day, locations of injury and locations of residences are similar. However, later at night, the injury location of highest density shifts to a "nightlife" district, whereas the residence locations of those most at risk of injury do not change.

  6. Guidelines for Assessment of Gait and Reference Values for Spatiotemporal Gait Parameters in Older Adults: The Biomathics and Canadian Gait Consortiums Initiative.

    Science.gov (United States)

    Beauchet, Olivier; Allali, Gilles; Sekhon, Harmehr; Verghese, Joe; Guilain, Sylvie; Steinmetz, Jean-Paul; Kressig, Reto W; Barden, John M; Szturm, Tony; Launay, Cyrille P; Grenier, Sébastien; Bherer, Louis; Liu-Ambrose, Teresa; Chester, Vicky L; Callisaya, Michele L; Srikanth, Velandai; Léonard, Guillaume; De Cock, Anne-Marie; Sawa, Ryuichi; Duque, Gustavo; Camicioli, Richard; Helbostad, Jorunn L

    2017-01-01

    Background: Gait disorders, a highly prevalent condition in older adults, are associated with several adverse health consequences. Gait analysis allows qualitative and quantitative assessments of gait that improves the understanding of mechanisms of gait disorders and the choice of interventions. This manuscript aims (1) to give consensus guidance for clinical and spatiotemporal gait analysis based on the recorded footfalls in older adults aged 65 years and over, and (2) to provide reference values for spatiotemporal gait parameters based on the recorded footfalls in healthy older adults free of cognitive impairment and multi-morbidities. Methods: International experts working in a network of two different consortiums (i.e., Biomathics and Canadian Gait Consortium) participated in this initiative. First, they identified items of standardized information following the usual procedure of formulation of consensus findings. Second, they merged databases including spatiotemporal gait assessments with GAITRite® system and clinical information from the "Gait, cOgnitiOn & Decline" (GOOD) initiative and the Generation 100 (Gen 100) study. Only healthy-free of cognitive impairment and multi-morbidities (i.e., ≤ 3 therapeutics taken daily)-participants aged 65 and older were selected. Age, sex, body mass index, mean values, and coefficients of variation (CoV) of gait parameters were used for the analyses. Results: Standardized systematic assessment of three categories of items, which were demographics and clinical information, and gait characteristics (clinical and spatiotemporal gait analysis based on the recorded footfalls), were selected for the proposed guidelines. Two complementary sets of items were distinguished: a minimal data set and a full data set. In addition, a total of 954 participants (mean age 72.8 ± 4.8 years, 45.8% women) were recruited to establish the reference values. Performance of spatiotemporal gait parameters based on the recorded footfalls

  7. Guidelines for Assessment of Gait and Reference Values for Spatiotemporal Gait Parameters in Older Adults: The Biomathics and Canadian Gait Consortiums Initiative

    Directory of Open Access Journals (Sweden)

    Olivier Beauchet

    2017-08-01

    Full Text Available Background: Gait disorders, a highly prevalent condition in older adults, are associated with several adverse health consequences. Gait analysis allows qualitative and quantitative assessments of gait that improves the understanding of mechanisms of gait disorders and the choice of interventions. This manuscript aims (1 to give consensus guidance for clinical and spatiotemporal gait analysis based on the recorded footfalls in older adults aged 65 years and over, and (2 to provide reference values for spatiotemporal gait parameters based on the recorded footfalls in healthy older adults free of cognitive impairment and multi-morbidities.Methods: International experts working in a network of two different consortiums (i.e., Biomathics and Canadian Gait Consortium participated in this initiative. First, they identified items of standardized information following the usual procedure of formulation of consensus findings. Second, they merged databases including spatiotemporal gait assessments with GAITRite® system and clinical information from the “Gait, cOgnitiOn & Decline” (GOOD initiative and the Generation 100 (Gen 100 study. Only healthy—free of cognitive impairment and multi-morbidities (i.e., ≤ 3 therapeutics taken daily—participants aged 65 and older were selected. Age, sex, body mass index, mean values, and coefficients of variation (CoV of gait parameters were used for the analyses.Results: Standardized systematic assessment of three categories of items, which were demographics and clinical information, and gait characteristics (clinical and spatiotemporal gait analysis based on the recorded footfalls, were selected for the proposed guidelines. Two complementary sets of items were distinguished: a minimal data set and a full data set. In addition, a total of 954 participants (mean age 72.8 ± 4.8 years, 45.8% women were recruited to establish the reference values. Performance of spatiotemporal gait parameters based on the recorded

  8. Mobility Work

    DEFF Research Database (Denmark)

    Bardram, Jakob Eyvind; Bossen, Claus

    2005-01-01

    We posit the concept of Mobility Work to describe efforts of moving about people and things as part of accomplishing tasks. Mobility work can be seen as a spatial parallel to the concept of articulation work proposed by the sociologist Anselm Strauss. Articulation work describes efforts...... of coordination necessary in cooperative work, but focuses, we argue, mainly on the temporal aspects of cooperative work. As a supplement, the concept of mobility work focuses on the spatial aspects of cooperative work. Whereas actors seek to diminish the amount of articulation work needed in collaboration...... by constructing Standard Operation Procedures (SOPs), actors minimise mobility work by constructing Standard Operation Configurations (SOCs). We apply the concept of mobility work to the ethnography of hospital work, and argue that mobility arises because of the need to get access to people, places, knowledge and...

  9. A Hierarchical Bayesian M/EEG Imaging Method Correcting for Incomplete Spatio-Temporal Priors

    DEFF Research Database (Denmark)

    Stahlhut, Carsten; Attias, Hagai T.; Sekihara, Kensuke

    2013-01-01

    In this paper we present a hierarchical Bayesian model, to tackle the highly ill-posed problem that follows with MEG and EEG source imaging. Our model promotes spatiotemporal patterns through the use of both spatial and temporal basis functions. While in contrast to most previous spatio-temporal ......In this paper we present a hierarchical Bayesian model, to tackle the highly ill-posed problem that follows with MEG and EEG source imaging. Our model promotes spatiotemporal patterns through the use of both spatial and temporal basis functions. While in contrast to most previous spatio...

  10. Spatio-temporal characterization of the multiple current pulse regime of diffuse barrier discharges in helium with nitrogen admixtures

    Science.gov (United States)

    Bogaczyk, Marc; Tschiersch, Robert; Nemschokmichal, Sebastian; Meichsner, Jürgen

    2017-10-01

    This work reports on the spatio-temporal characterization of the multiple current pulse regime of diffuse barrier discharges driven by sine-wave feeding voltage at a frequency of 2~kHz in helium with small nitrogen admixtures. The discharge gap of 3~mm is bounded by glass plates on both plane electrodes. Priority is given to the lateral discharge inhomogeneities, underlying volume- and surface-memory effects, and the breakdown mechanism. Therefore, relevant processes in the discharge volume and on the dielectric surfaces were investigated by ICCD camera imaging and optical emission spectroscopy in combination with electrical measurements and surface charge diagnostics using the electro-optic Pockels effect of a bismuth silicon oxide crystal. The number of current pulses per half-cycle of the sine-wave voltage rises with increasing nitrogen admixture to helium due to the predominant role of the Penning ionization. Here, the transition from the first glow-like breakdown to the last Townsend-like breakdown is favored by residual species from the former breakdowns which enhance the secondary electron emission during the pre-phase of the later breakdowns. Moreover, the surface charge measurements reveal that the consecutive breakdowns occur alternately at central and peripheral regions on the electrode surface. These spatial inhomogeneities are conserved by the surface charge memory effect as pointed out by the recalculated spatio-temporal development of the gap voltage.

  11. Asymmetry of light absorption upon propagation of focused femtosecond laser pulses with spatiotemporal coupling through glass materials

    Science.gov (United States)

    Zhukov, Vladimir P.; Bulgakova, Nadezhda M.

    2017-05-01

    Ultrashort laser pulses are usually described in terms of temporal and spatial dependences of their electric field, assuming that the spatial dependence is separable from time dependence. However, in most situations this assumption is incorrect as generation of ultrashort pulses and their manipulation lead to couplings between spatial and temporal coordinates resulting in various effects such as pulse front tilt and spatial chirp. One of the most intriguing spatiotemporal coupling effects is the so-called "lighthouse effect", the phase front rotation with the beam propagation distance [Akturk et al., Opt. Express 13, 8642 (2005)]. The interaction of spatiotemporally coupled laser pulses with transparent materials have interesting peculiarities, such as the effect of nonreciprocal writing, which can be used to facilitate microfabrication of photonic structures inside optical glasses. In this work, we make an attempt to numerically investigate the influence of the pulse front tilt and the lighthouse effect on the absorption of laser energy inside fused silica glass. The model, which is based on nonlinear Maxwell's equations supplemented by the hydrodynamic equations for free electron plasma, is applied. As three-dimensional solution of such a problem would require huge computational resources, a simplified two-dimensional model has been proposed. It has enabled to gain a qualitative insight into the features of propagation of ultrashort laser pulses with the tilted front in the regimes of volumetric laser modification of transparent materials, including directional asymmetry upon direct laser writing in glass materials.

  12. Human Depth Sensors-Based Activity Recognition Using Spatiotemporal Features and Hidden Markov Model for Smart Environments

    Directory of Open Access Journals (Sweden)

    Ahmad Jalal

    2016-01-01

    Full Text Available Nowadays, advancements in depth imaging technologies have made human activity recognition (HAR reliable without attaching optical markers or any other motion sensors to human body parts. This study presents a depth imaging-based HAR system to monitor and recognize human activities. In this work, we proposed spatiotemporal features approach to detect, track, and recognize human silhouettes using a sequence of RGB-D images. Under our proposed HAR framework, the required procedure includes detection of human depth silhouettes from the raw depth image sequence, removing background noise, and tracking of human silhouettes using frame differentiation constraints of human motion information. These depth silhouettes extract the spatiotemporal features based on depth sequential history, motion identification, optical flow, and joints information. Then, these features are processed by principal component analysis for dimension reduction and better feature representation. Finally, these optimal features are trained and they recognized activity using hidden Markov model. During experimental results, we demonstrate our proposed approach on three challenging depth videos datasets including IM-DailyDepthActivity, MSRAction3D, and MSRDailyActivity3D. All experimental results show the superiority of the proposed approach over the state-of-the-art methods.

  13. Tracking and mapping of spatiotemporal quantities using unicellular swarm intelligence visualisation of invisible hazardous substances using unicellular swarm intelligence

    CERN Document Server

    Oyekan, John Oluwagbemiga

    2016-01-01

    The book discusses new algorithms capable of searching for, tracking, mapping and providing a visualization of invisible substances. It reports on the realization of a bacterium-inspired robotic controller that can be used by an agent to search for any environmental spatial function such as temperature or pollution. Using the parameters of a mathematical model, the book shows that it is possible to control the exploration, exploitation and sensitivity of the agent. This feature sets the work apart from the usual method of applying the bacterium behavior to robotic agents. The book also discusses how a computationally tractable multi-agent robotic controller was developed and used to track as well as provide a visual map of a spatio-temporal distribution of a substance. On the one hand, this book provides biologists and ecologists with a basis to perform simulations related to how individual organisms respond to spatio-temporal factors in their environment as well as predict and analyze the behavior of organis...

  14. Spatio-Temporal Characteristics of Resident Trip Based on Poi and OD Data of Float CAR in Beijing

    Science.gov (United States)

    Mou, N.; Li, J.; Zhang, L.; Liu, W.; Xu, Y.

    2017-09-01

    Due to the influence of the urban inherent regional functional distribution, the daily activities of the residents presented some spatio-temporal patterns (periodic patterns, gathering patterns, etc.). In order to further understand the spatial and temporal characteristics of urban residents, this paper research takes the taxi trajectory data of Beijing as a sample data and studies the spatio-temporal characteristics of the residents' activities on the weekdays. At first, according to the characteristics of the taxi trajectory data distributed along the road network, it takes the Voronoi generated by the road nodes as the research unit. This paper proposes a hybrid clustering method - based on grid density, which is used to cluster the OD (origin and destination) data of taxi at different times. Then combining with the POI data of Beijing, this research calculated the density of the POI data in the clustering results, and analyzed the relationship between the activities of residents in different periods and the functional types of the region. The final results showed that the residents were mainly commuting on weekdays. And it found that the distribution of travel density showed a concentric circle of the characteristics, focusing on residential areas and work areas. The results of cluster analysis and POI analysis showed that the residents' travel had experienced the process of "spatial relative dispersion - spatial aggregation - spatial relative dispersion" in one day.

  15. SPATIO-TEMPORAL CHARACTERISTICS OF RESIDENT TRIP BASED ON POI AND OD DATA OF FLOAT CAR IN BEIJING

    Directory of Open Access Journals (Sweden)

    N. Mou

    2017-09-01

    Full Text Available Due to the influence of the urban inherent regional functional distribution, the daily activities of the residents presented some spatio-temporal patterns (periodic patterns, gathering patterns, etc.. In order to further understand the spatial and temporal characteristics of urban residents, this paper research takes the taxi trajectory data of Beijing as a sample data and studies the spatio-temporal characteristics of the residents' activities on the weekdays. At first, according to the characteristics of the taxi trajectory data distributed along the road network, it takes the Voronoi generated by the road nodes as the research unit. This paper proposes a hybrid clustering method – based on grid density, which is used to cluster the OD (origin and destination data of taxi at different times. Then,combining with the POI data of Beijing, this research calculated the density of the POI data in the clustering results, and analyzed the relationship between the activities of residents in different periods and the functional types of the region. The final results showed that the residents were mainly commuting on weekdays. And it found that the distribution of travel density showed a concentric circle of the characteristics, focusing on residential areas and work areas. The results of cluster analysis and POI analysis showed that the residents' travel had experienced the process of "spatial relative dispersion – spatial aggregation – spatial relative dispersion" in one day.

  16. Working memory for braille is shaped by experience.

    Science.gov (United States)

    Cohen, Henri; Scherzer, Peter; Viau, Robert; Voss, Patrice; Lepore, Franco

    2011-03-01

    Tactile working memory was found to be more developed in completely blind (congenital and acquired) than in semi-sighted subjects, indicating that experience plays a crucial role in shaping working memory. A model of working memory, adapted from the classical model proposed by Baddeley and Hitch1 and Baddeley2 is presented where the connection strengths of a highly cross-modal network are altered through experience.

  17. Meta-Analisis: Working Memory Dan Literasi Pada Anak Disleksia

    OpenAIRE

    Raharjo, Trubus

    2017-01-01

    This meta-analysis aims to find out the working memory relationship with literacy reading in dyslexic children. Neuropsychological disorders can occur in individuals with dyslexia and this is related to reading literacy. Reading literacy is a cognitive ability to generate information, store stimuli and process phonology. Individuals with poor reading ability may be affected by working memory. A total of 2,324 samples and 29 working memory data relationships with literacy reading were collecte...

  18. Bit-depth extension using spatiotemporal microdither based on models of the equivalent input noise of the visual system

    Science.gov (United States)

    Daly, Scott J.; Feng, Xiaofan

    2003-01-01

    Continuous tone, or "contone", imagery usually has 24 bits/pixel as a minimum, with eight bits each for the three primaries in typical displays. However, lower-cost displays constrain this number because of various system limitations. Conversely, high quality displays seek to achieve 9-10 bits/pixel/color, though there may be system bottlenecks limited at 8. The two main artifacts from reduced bit-depth are contouring and loss of amplitude detail; these can be prevented by dithering the image prior to these bit-depth losses. Early work in this area includes Roberts" noise modulation technique, Mista"s blue noise mask, Tyler"s technique of bit-stealing, and Mulligan"s use of the visual system"s spatiotemporal properties for spatiotemporal dithering. However, most halftoning/dithering work was primarily directed to displays at the lower end of bits/pixel (e.g., 1 bit as in halftoning) and higher ppi. Like Tyler, we approach the problem from the higher end of bits/pixel/color, say 6-8, and use available high frequency color content to generate even higher luminance amplitude resolution. Bit-depth extension with a high starting bit-depth (and often lower spatial resolution) changes the game substantially from halftoning experience. For example, complex algorithms like error diffusion and annealing are not needed, just the simple addition of noise. Instead of a spatial dither, it is better to use an amplitude dither, termed microdither by Pappas. We have looked at methods of generating the highest invisible opponent color spatiotemporal noise and other patterns, and have used Ahumada"s concept of equivalent input noise to guide our work. This paper will report on techniques and observations made in achieving contone quality on ~100 ppi 6 bits/pixel/color LCD displays with no visible dither patterns, noise, contours, or loss of amplitude detail at viewing distances as close as the near focus limit (~120 mm). These include the interaction of display nonlinearities and

  19. Ethnicity and spatiotemporal parameters of bilateral and unilateral transtibial amputees in a 100-m sprint

    National Research Council Canada - National Science Library

    Hobara, Hiroaki; Hashizume, Satoru; Kobayashi, Yoshiyuki; Usami, Yuko; Mochimaru, Masaaki

    2016-01-01

    ...) amputee sprinters, not Asian (AS) sprinters. Although these results indicate differences in sprint performance due to ethnicity, little is known about the ethnicity and spatiotemporal parameters of the 100-m sprint for amputee sprinters...

  20. Predicting the spatiotemporal dynamics of hair follicle patterns in the developing mouse

    National Research Council Canada - National Science Library

    Chi Wa Cheng; Ben Niu; Mya Warren; Larysa Halyna Pevny; Robin Lovell-Badge; Terence Hwa; Kathryn S. E. Cheah

    2014-01-01

    .... We used the expression of sex-determining region Y box 2 to identify and distinguish the primary and secondary hair follicles and to infer the spatiotemporal dynamics of the follicle formation process...

  1. ANALYZING THE SPATIOTEMPORAL DISTRIBUTION OF DIFFERENT INDUSTRIES IN WUHAN CITY USING ENTERPRISE REGISTRATION DATA

    National Research Council Canada - National Science Library

    Z. Cui; G. Xie; Z. Gui; H. Wu

    2017-01-01

    .... Based on the enterprises registration data of Administrator for Industry and Commerce of Wuhan from 1996 to 2007, in this paper, we analysed the spatiotemporal distribution of enterprises in Wuhan city...

  2. Spatiotemporal High-Resolution Cloud Mapping with a Ground-Based IR Scanner

    NARCIS (Netherlands)

    Brede, Benjamin; Thies, Boris; Bendix, Jörg; Feister, Uwe

    2017-01-01

    The high spatiotemporal variability of clouds requires automated monitoring systems. This study presents a retrieval algorithm that evaluates observations of a hemispherically scanning thermal infrared radiometer, the NubiScope, to produce georeferenced, spatially explicit cloud maps. The algorithm

  3. Spatiotemporal Changes in Crop Residues with Potential for Bioenergy Use in China from 1990 to 2010

    National Research Council Canada - National Science Library

    Xinliang Xu; Ying Fu; Shuang Li

    2013-01-01

      China has abundant crop residues (CRE) that could be used for bioenergy. The spatiotemporal characteristics of bioenergy production are crucial for high-efficiency use and appropriate management of bioenergy enterprises...

  4. Bayesian spatio-temporal modeling of particulate matter concentrations in Peninsular Malaysia

    Science.gov (United States)

    Manga, Edna; Awang, Norhashidah

    2016-06-01

    This article presents an application of a Bayesian spatio-temporal Gaussian process (GP) model on particulate matter concentrations from Peninsular Malaysia. We analyze daily PM10 concentration levels from 35 monitoring sites in June and July 2011. The spatiotemporal model set in a Bayesian hierarchical framework allows for inclusion of informative covariates, meteorological variables and spatiotemporal interactions. Posterior density estimates of the model parameters are obtained by Markov chain Monte Carlo methods. Preliminary data analysis indicate information on PM10 levels at sites classified as industrial locations could explain part of the space time variations. We include the site-type indicator in our modeling efforts. Results of the parameter estimates for the fitted GP model show significant spatio-temporal structure and positive effect of the location-type explanatory variable. We also compute some validation criteria for the out of sample sites that show the adequacy of the model for predicting PM10 at unmonitored sites.

  5. Spatio-Temporal Analysis of Epidemic Phenomena Using the R Package surveillance

    National Research Council Canada - National Science Library

    Meyer, Sebastian; Held, Leonhard; Höhle, Michael

    2017-01-01

    The availability of geocoded health data and the inherent temporal structure of communicable diseases have led to an increased interest in statistical models and software for spatio-temporal data with epidemic features...

  6. Spatiotemporal characteristics of organic contaminant concentrations and ecological risk assessment in the Songhua River, China

    Science.gov (United States)

    To control source pollution and improve water quality, an understanding of the spatiotemporal characteristics of organic contaminant concentrations in affected receiving waters is necessary. The Songhua River in northeast China is the country's third-largest domestic river and lo...

  7. Spatiotemporal and Kinematic Parameters Relating to Oriented Gait and Turn Performance in Patients with Chronic Stroke

    National Research Council Canada - National Science Library

    Bonnyaud, Céline; Pradon, Didier; Vuillerme, Nicolas; Bensmail, Djamel; Roche, Nicolas

    2015-01-01

    ... and therefore may help to guide rehabilitation. The aim of this study was thus to determine the spatiotemporal and kinematic parameters which were most related to the walking and turning sub-tasks of TUG performance in stroke patients...

  8. Spatio-temporal analysis of the national parks in Nigeria using ...

    African Journals Online (AJOL)

    Spatio-temporal analysis of the national parks in Nigeria using geographic information system. S O Mohammed, E N Gajere, E O Eguaroje, H Shaba, J O Ogbole, Y S Mangut, N D Onyeuwaoma, I S Kolawole ...

  9. Kronecker PCA based spatio-temporal modeling of video for dismount classification

    Science.gov (United States)

    Greenewald, Kristjan H.; Hero, Alfred O.

    2014-06-01

    We consider the application of KronPCA spatio-temporal modeling techniques1, 2 to the extraction of spatiotemporal features for video dismount classification. KronPCA performs a low-rank type of dimensionality reduction that is adapted to spatio-temporal data and is characterized by the T frame multiframe mean μ and covariance ∑ of p spatial features. For further regularization and improved inverse estimation, we also use the diagonally corrected KronPCA shrinkage methods we presented in.1 We apply this very general method to the modeling of the multivariate temporal behavior of HOG features extracted from pedestrian bounding boxes in video, with gender classification in a challenging dataset chosen as a specific application. The learned covariances for each class are used to extract spatiotemporal features which are then classified, achieving competitive classification performance.

  10. Comparing infants' use of featural and spatiotemporal information when individuating objects in an event monitoring design

    DEFF Research Database (Denmark)

    Krøjgaard, Peter

    , to what extent infants rely on spatiotemporal or featural object information when individuating objects is currently under debate. Hitherto, infants' use of spatiotemporal and featural object information has only been compared directly using the rather cognitively demanding event mapping design....... The results obtained using this design reveal that infants are more successful using spatiotemporal object information than when using featural information. However, recent studies using the less cognitively demanding event monitoring design have revealed that even younger infants are capable of object...... in the present series of experiments in which infants' use of spatiotemporal and featural information is compared directly using the less demanding event monitoring design. The results are discussed in relation to existing empirical evidence....

  11. Seasonal and spatial heterogeneities in host and vector abundances impact the spatiotemporal spread of bluetongue

    National Research Council Canada - National Science Library

    Charron, Maud V P; Kluiters, Georgette; Langlais, Michel; Seegers, Henri; Baylis, Matthew; Ezanno, Pauline

    2013-01-01

    .... Our objective was to assess, using a modelling approach, how spatiotemporal heterogeneities in abundance and distribution of hosts and vectors impact the occurrence and amplitude of local and regional BT epidemics...

  12. INCREMENTAL PRINCIPAL COMPONENT ANALYSIS BASED OUTLIER DETECTION METHODS FOR SPATIOTEMPORAL DATA STREAMS

    Directory of Open Access Journals (Sweden)

    A. Bhushan

    2015-07-01

    Full Text Available In this paper, we address outliers in spatiotemporal data streams obtained from sensors placed across geographically distributed locations. Outliers may appear in such sensor data due to various reasons such as instrumental error and environmental change. Real-time detection of these outliers is essential to prevent propagation of errors in subsequent analyses and results. Incremental Principal Component Analysis (IPCA is one possible approach for detecting outliers in such type of spatiotemporal data streams. IPCA has been widely used in many real-time applications such as credit card fraud detection, pattern recognition, and image analysis. However, the suitability of applying IPCA for outlier detection in spatiotemporal data streams is unknown and needs to be investigated. To fill this research gap, this paper contributes by presenting two new IPCA-based outlier detection methods and performing a comparative analysis with the existing IPCA-based outlier detection methods to assess their suitability for spatiotemporal sensor data streams.

  13. Spatiotemporal evolution of water storage changes in India from the updated GRACE‐derived gravity records

    National Research Council Canada - National Science Library

    Panda, Dileep K; Wahr, John

    2016-01-01

    ...). The spatiotemporal evolution of GRACE data reflects consistent patterns with that of several hydroclimatic variables and also shows that most of the water loss has occurred in the northern parts of India...

  14. Activity fragmentation, ICT and travel : An exploratory path analysis of spatiotemporal interrelationships

    NARCIS (Netherlands)

    Ben-Elia, Eran; Alexander, Bayarma; Hubers, Christa; Ettema, Dick

    2014-01-01

    This paper focuses on the interrelationships between ICT, activity fragmentation and travel behaviour. The concept of fragmentation relates to how activities are spatiotemporally reorganized, by subdividing activities into smaller components that are then performed at different times and/or

  15. General Spatiotemporal Patterns of Urbanization: An Examination of 16 World Cities

    OpenAIRE

    Zhifeng Liu; Chunyang He; Jianguo Wu

    2016-01-01

    Urbanization is the most dramatic form of land use change that has profoundly influenced environmental and socioeconomic conditions around the world. To assess these impacts and promote urban sustainability, a better understanding of urbanization patterns is needed. Recent studies have suggested several spatiotemporal patterns of urbanization, but their generality is yet to be adequately tested with long-term data. Thus, the main goal of our study was two-fold: (1) to examine the spatiotempor...

  16. Multivariate exploration of non-intrusive load monitoring via spatiotemporal pattern network

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chao; Akintayo, Adedotun; Jiang, Zhanhong; Henze, Gregor P.; Sarkar, Soumik

    2018-02-01

    Non-intrusive load monitoring (NILM) of electrical demand for the purpose of identifying load components has thus far mostly been studied using univariate data, e.g., using only whole building electricity consumption time series to identify a certain type of end-use such as lighting load. However, using additional variables in the form of multivariate time series data may provide more information in terms of extracting distinguishable features in the context of energy disaggregation. In this work, a novel probabilistic graphical modeling approach, namely the spatiotemporal pattern network (STPN) is proposed for energy disaggregation using multivariate time-series data. The STPN framework is shown to be capable of handling diverse types of multivariate time-series to improve the energy disaggregation performance. The technique outperforms the state of the art factorial hidden Markov models (FHMM) and combinatorial optimization (CO) techniques in multiple real-life test cases. Furthermore, based on two homes' aggregate electric consumption data, a similarity metric is defined for the energy disaggregation of one home using a trained model based on the other home (i.e., out-of-sample case). The proposed similarity metric allows us to enhance scalability via learning supervised models for a few homes and deploying such models to many other similar but unmodeled homes with significantly high disaggregation accuracy.

  17. Water Quality Sensing and Spatio-Temporal Monitoring Structure with Autocorrelation Kernel Methods

    Directory of Open Access Journals (Sweden)

    Iván P. Vizcaíno

    2017-10-01

    Full Text Available Pollution on water resources is usually analyzed with monitoring campaigns, which consist of programmed sampling, measurement, and recording of the most representative water quality parameters. These campaign measurements yields a non-uniform spatio-temporal sampled data structure to characterize complex dynamics phenomena. In this work, we propose an enhanced statistical interpolation method to provide water quality managers with statistically interpolated representations of spatial-temporal dynamics. Specifically, our proposal makes efficient use of the a priori available information of the quality parameter measurements through Support Vector Regression (SVR based on Mercer’s kernels. The methods are benchmarked against previously proposed methods in three segments of the Machángara River and one segment of the San Pedro River in Ecuador, and their different dynamics are shown by statistically interpolated spatial-temporal maps. The best interpolation performance in terms of mean absolute error was the SVR with Mercer’s kernel given by either the Mahalanobis spatial-temporal covariance matrix or by the bivariate estimated autocorrelation function. In particular, the autocorrelation kernel provides with significant improvement of the estimation quality, consistently for all the six water quality variables, which points out the relevance of including a priori knowledge of the problem.

  18. YAG:Nd scanning laser with intracavity PLZT-based spatio-temporal light modulator

    Science.gov (United States)

    Alekseev, V. N.; Kotylev, V. N.; Liber, V. I.

    2003-08-01

    We report advancements in electrically controlled scanning of the direction of laser radiation preceded in 1-3 with application to the YAG:Nd and Cu vapor lasers its key specifications determined by intracavity PLZT spatio-temporal light modulator (STLM) located within a linear conjugate cavity. In the present work the results of an experimental research into the radiation characteristics of the laser with a polarizing output of radiation from the resonator are given. One of the lenses of the conjugate laser resonator is a cylindrical lens. Due to optical relief of the STLM and use of a cylindrical lens the output energy of a lasing pulse is increased signifciantly. The laser radiation scans along the vertical coordinate and is specified by packets of 10-20 pulses with the 15-50 kHz repetition frequency in a packet, up to 10 mJ energy, and the 150-250 ns pulse duration. The laser is operating in the 5-10Hz pulse repetition regime with 1 millisecond duration pumping pulse. Movement of the article during marking provides the second coordiate. STLM based scanning laser is an effective alternative both to jet markers for articles moving on a conveyor belt and the existing laser markers with optomechanical scanning. Capabilities to enhance overall performance of the scanning laser are discussed and samples of markings obtained on different materials demonstrated.

  19. Spatiotemporal review of the torrential flood phenomenon in the Morava river basin

    Directory of Open Access Journals (Sweden)

    Petrović Ana M.

    2015-01-01

    Full Text Available Phenomenon of torrential floods as the most destructive and the most frequent natural hazards in Serbia with serious socioeconomic, cultural and environmental consequences deserve special attention. In this paper, data collection strategy and data analysis with the aim of spatiotemporal characterization of the torrential flood phenomenon in the largest national, Morava river basin, are presented. A dataset (derived from the Inventory of torrential floods in Serbia of 479 registered torrential flood events with over 84 casualties for the period 1926-2013 is presented. Monthly distribution of registered torrential floods indicates that the majority of events with the highest share of death toll occurred in the late spring, from May to the end of June. According to the annual distribution there is a linear increase of torrential flood occurrence in the course of 88 years, but decrease of death toll is found. The greatest number of torrential flood events and casualties is registered in the Južna Morava river basin (watersheds of Nišava, Toplica, Veternica, Jablanica. The results of this work can be of great value in the implementation of the Flood Directive of the European Commission on a river basin level as well as for the future natural hazards information system in Serbia. [Projekat Ministarstva nauke Republike Srbije, br. 47007III

  20. Spatiotemporal chemical dynamics in living cells: from information trafficking to cell physiology.

    Science.gov (United States)

    Petty, Howard R

    2006-01-01

    Biological thought in the 20th century was dominated by the study of structures at increasingly minute levels. For biology to advance beyond structural reductionism and contribute its full measure to clinical care, living biological structures must be understood in the context of their collective chemical processes at the relevant chemical time-scales. Using high-speed fluorescence microscopy, we have studied intra- and inter-cellular signaling using shutter speeds ( approximately 100 ns) that remove the effects of wave motion and diffusion from optical images. By collecting a series of such images, stop-action movies of signal trafficking in living cells are created; these have revealed a new level of spatiotemporal chemical organization within cells. Numerous types of chemical waves have been found in living cells expressing a great variety of physical properties. In this article I will review some of these basic findings, discuss these events in the context of information trafficking, and illustrate the potential implications of this work in medicine.

  1. The spatiotemporal characteristics of elementary audiovisual speech and music processing in musically untrained subjects.

    Science.gov (United States)

    Elmer, Stefan; Meyer, Martin; Jäncke, Lutz

    2012-03-01

    Previously, the EEG technique has been used to investigate the spatiotemporal properties of audiovisual (AV) processing by taking advantage of the violation of the "additive model", which is considered to be a very conservative approach. In the present work, we used a less conservative and novel approach than the criterion of superadditivity for estimating AV interactions. Hence, we estimated AV interaction patterns by comparing the responses to AV stimuli with the averaged responses to the unimodal visual and auditory stimuli in musically untrained subjects and by presenting syllables and piano tones coupled with flashlights. Our results suggest that the two AV objects elicited consistent interaction patterns within the time course of unisensory processing in the time range between 80 and 250ms post stimulus onset. The scalp topographies, as well as the source estimation approach we adopted, indicate that the first interaction pattern at around 100ms was partially driven by auditory-related cortical regions. Additionally, we found evidence for a second interaction pattern at around 200ms that was mainly associated with the responsiveness of extra-sensory brain regions. During this later processing stage, only the music condition was associated with putative responses that originated from auditory-related cortical fields. This study provides a novel approach to investigate the basic principles underlying elementary AV speech and music processing in subjects without formal musical education. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Methods for generating non-separable spatiotemporal covariance models with potential environmental applications

    Science.gov (United States)

    Kolovos, A.; Christakos, G.; Hristopulos, D. T.; Serre, M. L.

    2004-08-01

    Environmental processes (e.g., groundwater contaminants, air pollution patterns, air-water and air-soil energy exchanges) are characterized by variability and uncertainty. Spatiotemporal random fields are used to represent correlations between fluctuations in the composite space-time domain. Modelling the effects of fluctuations with suitable covariance functions can improve our ability to characterize and predict space-time variations in various natural systems (e.g., environmental media, long-term climatic evolutions on local/global scales, and human exposure to pollutants). The goal of this work is to present the reader with various methods for constructing space-time covariance models. In this context, we provide a mathematical exposition and visual representations of several theoretical covariance models. These include non-separable (in space and time) covariance models derived from physical laws (i.e., differential equations and dynamic rules), spectral functions, and generalized random fields. It is also shown that non-separability is often a direct result of the physical laws that govern the process. The proposed methods can generate covariance models for homogeneous/stationary as well as for non-homogeneous/non-stationary environmental processes across space and time. We investigate several properties (short-range and asymptotic behavior, shape of the covariance function etc.) of these models and present plots of the space-time dependence for various parameter values.

  3. Water Quality Sensing and Spatio-Temporal Monitoring Structure with Autocorrelation Kernel Methods.

    Science.gov (United States)

    Vizcaíno, Iván P; Carrera, Enrique V; Muñoz-Romero, Sergio; Cumbal, Luis H; Rojo-Álvarez, José Luis

    2017-10-16

    Pollution on water resources is usually analyzed with monitoring campaigns, which consist of programmed sampling, measurement, and recording of the most representative water quality parameters. These campaign measurements yields a non-uniform spatio-temporal sampled data structure to characterize complex dynamics phenomena. In this work, we propose an enhanced statistical interpolation method to provide water quality managers with statistically interpolated representations of spatial-temporal dynamics. Specifically, our proposal makes efficient use of the a priori available information of the quality parameter measurements through Support Vector Regression (SVR) based on Mercer's kernels. The methods are benchmarked against previously proposed methods in three segments of the Machángara River and one segment of the San Pedro River in Ecuador, and their different dynamics are shown by statistically interpolated spatial-temporal maps. The best interpolation performance in terms of mean absolute error was the SVR with Mercer's kernel given by either the Mahalanobis spatial-temporal covariance matrix or by the bivariate estimated autocorrelation function. In particular, the autocorrelation kernel provides with significant improvement of the estimation quality, consistently for all the six water quality variables, which points out the relevance of including a priori knowledge of the problem.

  4. Parallel Multivariate Spatio-Temporal Clustering of Large Ecological Datasets on Hybrid Supercomputers

    Energy Technology Data Exchange (ETDEWEB)

    Sreepathi, Sarat [ORNL; Kumar, Jitendra [ORNL; Mills, Richard T. [Argonne National Laboratory; Hoffman, Forrest M. [ORNL; Sripathi, Vamsi [Intel Corporation; Hargrove, William Walter [United States Department of Agriculture (USDA), United States Forest Service (USFS)

    2017-09-01

    A proliferation of data from vast networks of remote sensing platforms (satellites, unmanned aircraft systems (UAS), airborne etc.), observational facilities (meteorological, eddy covariance etc.), state-of-the-art sensors, and simulation models offer unprecedented opportunities for scientific discovery. Unsupervised classification is a widely applied data mining approach to derive insights from such data. However, classification of very large data sets is a complex computational problem that requires efficient numerical algorithms and implementations on high performance computing (HPC) platforms. Additionally, increasing power, space, cooling and efficiency requirements has led to the deployment of hybrid supercomputing platforms with complex architectures and memory hierarchies like the Titan system at Oak Ridge National Laboratory. The advent of such accelerated computing architectures offers new challenges and opportunities for big data analytics in general and specifically, large scale cluster analysis in our case. Although there is an existing body of work on parallel cluster analysis, those approaches do not fully meet the needs imposed by the nature and size of our large data sets. Moreover, they had scaling limitations and were mostly limited to traditional distributed memory computing platforms. We present a parallel Multivariate Spatio-Temporal Clustering (MSTC) technique based on k-means cluster analysis that can target hybrid supercomputers like Titan. We developed a hybrid MPI, CUDA and OpenACC implementation that can utilize both CPU and GPU resources on computational nodes. We describe performance results on Titan that demonstrate the scalability and efficacy of our approach in processing large ecological data sets.

  5. Spatio-temporal articulatory movement primitives during speech production: extraction, interpretation, and validation.

    Science.gov (United States)

    Ramanarayanan, Vikram; Goldstein, Louis; Narayanan, Shrikanth S

    2013-08-01

    This paper presents a computational approach to derive interpretable movement primitives from speech articulation data. It puts forth a convolutive Nonnegative Matrix Factorization algorithm with sparseness constraints (cNMFsc) to decompose a given data matrix into a set of spatiotemporal basis sequences and an activation matrix. The algorithm optimizes a cost function that trades off the mismatch between the proposed model and the input data against the number of primitives that are active at any given instant. The method is applied to both measured articulatory data obtained through electromagnetic articulography as well as synthetic data generated using an articulatory synthesizer. The paper then describes how to evaluate the algorithm performance quantitatively and further performs a qualitative assessment of the algorithm's ability to recover compositional structure from data. This is done using pseudo ground-truth primitives generated by the articulatory synthesizer based on an Articulatory Phonology frame-work [Browman and Goldstein (1995). "Dynamics and articulatory phonology," in Mind as motion: Explorations in the dynamics of cognition, edited by R. F. Port and T.van Gelder (MIT Press, Cambridge, MA), pp. 175-194]. The results suggest that the proposed algorithm extracts movement primitives from human speech production data that are linguistically interpretable. Such a framework might aid the understanding of longstanding issues in speech production such as motor control and coarticulation.

  6. Large-Scale Spatio-Temporal Patterns of Mediterranean Cephalopod Diversity.

    Directory of Open Access Journals (Sweden)

    Stefanie Keller

    Full Text Available Species diversity is widely recognized as an important trait of ecosystems' functioning and resilience. Understanding the causes of diversity patterns and their interaction with the environmental conditions is essential in order to effectively assess and preserve existing diversity. While diversity patterns of most recurrent groups such as fish are commonly studied, other important taxa such as cephalopods have received less attention. In this work we present spatio-temporal trends of cephalopod diversity across the entire Mediterranean Sea during the last 19 years, analysing data from the annual bottom trawl survey MEDITS conducted by 5 different Mediterranean countries using standardized gears and sampling protocols. The influence of local and regional environmental variability in different Mediterranean regions is analysed applying generalized additive models, using species richness and the Shannon Wiener index as diversity descriptors. While the western basin showed a high diversity, our analyses do not support a steady eastward decrease of diversity as proposed in some previous studies. Instead, high Shannon diversity was also found in the Adriatic and Aegean Seas, and high species richness in the eastern Ionian Sea. Overall diversity did not show any consistent trend over the last two decades. Except in the Adriatic Sea, diversity showed a hump-shaped trend with depth in all regions, being highest between 200-400 m depth. Our results indicate that high Chlorophyll a concentrations and warmer temperatures seem to enhance species diversity, and the influence of these parameters is stronger for richness than for Shannon diversity.

  7. Fish in a ring: spatio-temporal pattern formation in one-dimensional animal groups.

    Science.gov (United States)

    Abaid, Nicole; Porfiri, Maurizio

    2010-10-06

    In this work, we study the collective behaviour of fish shoals in annular domains. Shoal mates are modelled as self-propelled particles moving on a discrete lattice. Collective decision-making is determined by information exchange among neighbours. Neighbourhoods are specified using the perceptual limit and numerosity of fish. Fish self-propulsion and obedience to group decisions are described through random variables. Spatio-temporal schooling patterns are measured using coarse observables adapted from the literature on coupled oscillator networks and features of the time-varying network describing the fish-to-fish information exchange. Experiments on zebrafish schooling in an annular tank are used to validate the model. Effects of group size and obedience parameter on coarse observables and network features are explored to understand the implications of perceptual numerosity and spatial density on fish schooling. The proposed model is also compared with a more traditional metric model, in which the numerosity constraint is released and fish interactions depend only on physical configurations. Comparison shows that the topological regime on which the proposed model is constructed allows for interpreting characteristic behaviours observed in the experimental study that are not captured by the metric model.

  8. Spatiotemporal and molecular epidemiology of cutaneous leishmaniasis in Libya.

    Directory of Open Access Journals (Sweden)

    Ahmad Amro

    2017-09-01

    Full Text Available Cutaneous leishmaniasis (CL is a major public health problem in Libya. In this paper, we describe the eco-epidemiological parameters of CL during the armed conflict period from January 2011 till December 2012. Current spatiotemporal distributions of CL cases were explored and projected to the future using a correlative modelling approach. In addition the present results were compared with our previous data obtained for the time period 1995-2008.We investigated 312 CL patients who presented to the Dermatology Department at the Tripoli Central Hospital and came from 81 endemic areas distributed in 10 districts. The patients presented with typical localized lesions which appeared commonly on the face, arms and legs. Molecular identification of parasites by a PCR-RFLP approach targeting the ITS1 region of the rDNA was successful for 81 patients with two causative species identified: L. major and L. tropica comprised 59 (72.8% and 22 (27.2% cases, respectively. Around 77.3% of L. tropica CL and 57.7% of L. major CL caused single lesions. Five CL patients among our data set were seropositive for HIV. L. tropica was found mainly in three districts, Murqub (27.3%, Jabal al Gharbi (27.3% and Misrata (13.7% while L. major was found in two districts, in Jabal al Gharbi (61% and Jafara (20.3%. Seasonal occurrence of CL cases showed that most cases (74.2% admitted to the hospital between November and March, L. major cases from November till January (69.4%, and L. tropica cases mainly in January and February (41%. Two risk factors were identified for the two species; the presence of previously infected household members, and the presence of rodents and sandflies in patient's neighborhoods. Spatiotemporal projections using correlative distribution models based on current case data and climatic conditions showed that coastal regions have a higher level of risk due to more favourable conditions for the transmitting vectors.Future projection of CL until 2060

  9. STSE: Spatio-Temporal Simulation Environment Dedicated to Biology.

    Science.gov (United States)

    Stoma, Szymon; Fröhlich, Martina; Gerber, Susanne; Klipp, Edda

    2011-04-28

    Recently, the availability of high-resolution microscopy together with the advancements in the development of biomarkers as reporters of biomolecular interactions increased the importance of imaging methods in molecular cell biology. These techniques enable the investigation of cellular characteristics like volume, size and geometry as well as volume and geometry of intracellular compartments, and the amount of existing proteins in a spatially resolved manner. Such detailed investigations opened up many new areas of research in the study of spatial, complex and dynamic cellular systems. One of the crucial challenges for the study of such systems is the design of a well stuctured and optimized workflow to provide a systematic and efficient hypothesis verification. Computer Science can efficiently address this task by providing software that facilitates handling, analysis, and evaluation of biological data to the benefit of experimenters and modelers. The Spatio-Temporal Simulation Environment (STSE) is a set of open-source tools provided to conduct spatio-temporal simulations in discrete structures based on microscopy images. The framework contains modules to digitize, represent, analyze, and mathematically model spatial distributions of biochemical species. Graphical user interface (GUI) tools provided with the software enable meshing of the simulation space based on the Voronoi concept. In addition, it supports to automatically acquire spatial information to the mesh from the images based on pixel luminosity (e.g. corresponding to molecular levels from microscopy images). STSE is freely available either as a stand-alone version or included in the linux live distribution Systems Biology Operational Software (SB.OS) and can be downloaded from http://www.stse-software.org/. The Python source code as well as a comprehensive user manual and video tutorials are also offered to the research community. We discuss main concepts of the STSE design and workflow. We

  10. STSE: Spatio-Temporal Simulation Environment Dedicated to Biology

    Directory of Open Access Journals (Sweden)

    Gerber Susanne

    2011-04-01

    Full Text Available Abstract Background Recently, the availability of high-resolution microscopy together with the advancements in the development of biomarkers as reporters of biomolecular interactions increased the importance of imaging methods in molecular cell biology. These techniques enable the investigation of cellular characteristics like volume, size and geometry as well as volume and geometry of intracellular compartments, and the amount of existing proteins in a spatially resolved manner. Such detailed investigations opened up many new areas of research in the study of spatial, complex and dynamic cellular systems. One of the crucial challenges for the study of such systems is the design of a well stuctured and optimized workflow to provide a systematic and efficient hypothesis verification. Computer Science can efficiently address this task by providing software that facilitates handling, analysis, and evaluation of biological data to the benefit of experimenters and modelers. Results The Spatio-Temporal Simulation Environment (STSE is a set of open-source tools provided to conduct spatio-temporal simulations in discrete structures based on microscopy images. The framework contains modules to digitize, represent, analyze, and mathematically model spatial distributions of biochemical species. Graphical user interface (GUI tools provided with the software enable meshing of the simulation space based on the Voronoi concept. In addition, it supports to automatically acquire spatial information to the mesh from the images based on pixel luminosity (e.g. corresponding to molecular levels from microscopy images. STSE is freely available either as a stand-alone version or included in the linux live distribution Systems Biology Operational Software (SB.OS and can be downloaded from http://www.stse-software.org/. The Python source code as well as a comprehensive user manual and video tutorials are also offered to the research community. We discuss main concepts

  11. Spatiotemporal and molecular epidemiology of cutaneous leishmaniasis in Libya.

    Science.gov (United States)

    Amro, Ahmad; Al-Dwibe, Hamida; Gashout, Aisha; Moskalenko, Olga; Galafin, Marlena; Hamarsheh, Omar; Frohme, Marcus; Jaeschke, Anja; Schönian, Gabriele; Kuhls, Katrin

    2017-09-01

    Cutaneous leishmaniasis (CL) is a major public health problem in Libya. In this paper, we describe the eco-epidemiological parameters of CL during the armed conflict period from January 2011 till December 2012. Current spatiotemporal distributions of CL cases were explored and projected to the future using a correlative modelling approach. In addition the present results were compared with our previous data obtained for the time period 1995-2008. We investigated 312 CL patients who presented to the Dermatology Department at the Tripoli Central Hospital and came from 81 endemic areas distributed in 10 districts. The patients presented with typical localized lesions which appeared commonly on the face, arms and legs. Molecular identification of parasites by a PCR-RFLP approach targeting the ITS1 region of the rDNA was successful for 81 patients with two causative species identified: L. major and L. tropica comprised 59 (72.8%) and 22 (27.2%) cases, respectively. Around 77.3% of L. tropica CL and 57.7% of L. major CL caused single lesions. Five CL patients among our data set were seropositive for HIV. L. tropica was found mainly in three districts, Murqub (27.3%), Jabal al Gharbi (27.3%) and Misrata (13.7%) while L. major was found in two districts, in Jabal al Gharbi (61%) and Jafara (20.3%). Seasonal occurrence of CL cases showed that most cases (74.2%) admitted to the hospital between November and March, L. major cases from November till January (69.4%), and L. tropica cases mainly in January and February (41%). Two risk factors were identified for the two species; the presence of previously infected household members, and the presence of rodents and sandflies in patient's neighborhoods. Spatiotemporal projections using correlative distribution models based on current case data and climatic conditions showed that coastal regions have a higher level of risk due to more favourable conditions for the transmitting vectors. Future projection of CL until 2060 showed a

  12. Big Data GPU-Driven Parallel Processing Spatial and Spatio-Temporal Clustering Algorithms

    Science.gov (United States)

    Konstantaras, Antonios; Skounakis, Emmanouil; Kilty, James-Alexander; Frantzeskakis, Theofanis; Maravelakis, Emmanuel

    2016-04-01

    Advances in graphics processing units' technology towards encompassing parallel architectures [1], comprised of thousands of cores and multiples of parallel threads, provide the foundation in terms of hardware for the rapid processing of various parallel applications regarding seismic big data analysis. Seismic data are normally stored as collections of vectors in massive matrices, growing rapidly in size as wider areas are covered, denser recording networks are being established and decades of data are being compiled together [2]. Yet, many processes regarding seismic data analysis are performed on each seismic event independently or as distinct tiles [3] of specific grouped seismic events within a much larger data set. Such processes, independent of one another can be performed in parallel narrowing down processing times drastically [1,3]. This research work presents the development and implementation of three parallel processing algorithms using Cuda C [4] for the investigation of potentially distinct seismic regions [5,6] present in the vicinity of the southern Hellenic seismic arc. The algorithms, programmed and executed in parallel comparatively, are the: fuzzy k-means clustering with expert knowledge [7] in assigning overall clusters' number; density-based clustering [8]; and a selves-developed spatio-temporal clustering algorithm encompassing expert [9] and empirical knowledge [10] for the specific area under investigation. Indexing terms: GPU parallel programming, Cuda C, heterogeneous processing, distinct seismic regions, parallel clustering algorithms, spatio-temporal clustering References [1] Kirk, D. and Hwu, W.: 'Programming massively parallel processors - A hands-on approach', 2nd Edition, Morgan Kaufman Publisher, 2013 [2] Konstantaras, A., Valianatos, F., Varley, M.R. and Makris, J.P.: 'Soft-Computing Modelling of Seismicity in the Southern Hellenic Arc', Geoscience and Remote Sensing Letters, vol. 5 (3), pp. 323-327, 2008 [3] Papadakis, S. and

  13. Spatio-temporal patterns of forest fires: a comprehensive application of the K-function

    Science.gov (United States)

    Tonini, Marj; Vega Orozco, Carmen; Kanevski, Mikhaïl; Conedera, Marco

    2013-04-01

    temporal cluster behaviour at the corresponding temporal scale t. For the analysis of the space-time clustering, we applied the spatio-temporal (bivariate) K-function K(r,t), which evaluates if events are closer in both space and time. Intuitively, if there is no space-time interaction K(r,t) = K(r) * K(t). Accordingly, if K(r,t) minus K(r) * K(t) is positive, this indicates an interaction between space and time in producing clusters, which arise from a well detectable spatial and temporal scales. This study allowed detecting: 1) the purely spatial and the purely temporal scales at which the registered forest fires events are clustered, given by the results of the K(r) and the K(t) computations; and 2) the time period where spatial clusters take place at a given distance scale, exhibited by the results of the K(r,t) computation. Key words: spatio-temporal sequences, cluster, Ripley's K-function, forest fires. Acknowledgements This work was partly supported by the SNFS Project No. 200021-140658, "Analysis and Modelling of Space-Time Patterns in Complex Regions". References - Bivand R., Rowlingson B., and Diggle P. (2012) - splancs package in R project - Diggle P., Chetwynd A., Haggkvist R. and Morris S. (1995) Second-order analysis of space-time clustering. Statistical Methods in Medical Research, vol. 4(2): 124-136. - R Development Core Team (2012). R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria. URL: http://www.R-project.org/. - Vega Orozco C., Tonini M., Conedera M., Kanveski M. (2012) Cluster recognition in spatial-temporal sequences: the case of forest fires, GeoInformatica, vol. 16(4): 653-673.

  14. Developmental Work

    DEFF Research Database (Denmark)

    Møller, Niels; Hvid, Helge; Kristensen, Tage Søndergaard

    2003-01-01

    Human Deveoplment and Working Life - Work for Welfare explores whether the development of human resources at company level can improve individuals' quality of life, companies' possibilities of development, and welfare and democracy in society. Chapter two discuss the concept "developmental work......" from theoretical and empirical perspectives....

  15. Realigning thunder and lightning: temporal adaptation to spatiotemporally distant events.

    Directory of Open Access Journals (Sweden)

    Jordi Navarra

    Full Text Available The brain is able to realign asynchronous signals that approximately coincide in both space and time. Given that many experience-based links between visual and auditory stimuli are established in the absence of spatiotemporal proximity, we investigated whether or not temporal realignment arises in these conditions. Participants received a 3-min exposure to visual and auditory stimuli that were separated by 706 ms and appeared either from the same (Experiment 1 or from different spatial positions (Experiment 2. A simultaneity judgment task (SJ was administered right afterwards. Temporal realignment between vision and audition was observed, in both Experiment 1 and 2, when comparing the participants' SJs after this exposure phase with those obtained after a baseline exposure to audiovisual synchrony. However, this effect was present only when the visual stimuli preceded the auditory stimuli during the exposure to asynchrony. A similar pattern of results (temporal realignment after exposure to visual-leading asynchrony but not after exposure to auditory-leading asynchrony was obtained using temporal order judgments (TOJs instead of SJs (Experiment 3. Taken together, these results suggest that temporal recalibration still occurs for visual and auditory stimuli that fall clearly outside the so-called temporal window for multisensory integration and appear from different spatial positions. This temporal realignment may be modulated by long-term experience with the kind of asynchrony (vision-leading that we most frequently encounter in the outside world (e.g., while perceiving distant events.

  16. Spatiotemporal regulation of autophagy during Caenorhabditis elegans aging

    Science.gov (United States)

    Chang, Jessica T; Kumsta, Caroline; Hellman, Andrew B; Adams, Linnea M; Hansen, Malene

    2017-01-01

    Autophagy has been linked to longevity in many species, but the underlying mechanisms are unclear. Using a GFP-tagged and a new tandem-tagged Atg8/LGG-1 reporter, we quantified autophagic vesicles and performed autophagic flux assays in multiple tissues of wild-type Caenorhabditis elegans and long-lived daf-2/insulin/IGF-1 and glp-1/Notch mutants throughout adulthood. Our data are consistent with an age-related decline in autophagic activity in the intestine, body-wall muscle, pharynx, and neurons of wild-type animals. In contrast, daf-2 and glp-1 mutants displayed unique age- and tissue-specific changes in autophagic activity, indicating that the two longevity paradigms have distinct effects on autophagy during aging. Although autophagy appeared active in the intestine of both long-lived mutants, inhibition of intestinal autophagy significantly abrogated lifespan extension only in glp-1 mutants. Collectively, our data suggest that autophagic activity normally decreases with age in C. elegans, whereas daf-2 and glp-1 long-lived mutants regulate autophagy in distinct spatiotemporal-specific manners to extend lifespan. DOI: http://dx.doi.org/10.7554/eLife.18459.001 PMID:28675140

  17. Methodology for Clustering High-Resolution Spatiotemporal Solar Resource Data

    Energy Technology Data Exchange (ETDEWEB)

    Getman, Dan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lopez, Anthony [National Renewable Energy Lab. (NREL), Golden, CO (United States); Mai, Trieu [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dyson, Mark [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-09-01

    In this report, we introduce a methodology to achieve multiple levels of spatial resolution reduction of solar resource data, with minimal impact on data variability, for use in energy systems modeling. The selection of an appropriate clustering algorithm, parameter selection including cluster size, methods of temporal data segmentation, and methods of cluster evaluation are explored in the context of a repeatable process. In describing this process, we illustrate the steps in creating a reduced resolution, but still viable, dataset to support energy systems modeling, e.g. capacity expansion or production cost modeling. This process is demonstrated through the use of a solar resource dataset; however, the methods are applicable to other resource data represented through spatiotemporal grids, including wind data. In addition to energy modeling, the techniques demonstrated in this paper can be used in a novel top-down approach to assess renewable resources within many other contexts that leverage variability in resource data but require reduction in spatial resolution to accommodate modeling or computing constraints.

  18. Spatio-temporal models of synthetic genetic oscillators.

    Science.gov (United States)

    Macnamara, Cicely K; Chaplain, Mark A J

    2017-02-01

    Signal transduction pathways play a major role in many important aspects of cellular function e.g. cell division, apoptosis. One important class of signal transduction pathways is gene regulatory networks (GRNs). In many GRNs, proteins bind to gene sites in the nucleus thereby altering the transcription rate. Such proteins are known as transcription factors. If the binding reduces the transcription rate there is a negative feedback leading to oscillatory behaviour in mRNA and protein levels, both spatially (e.g. by observing fluorescently labelled molecules in single cells) and temporally (e.g. by observing protein/mRNA levels over time). Recent computational modelling has demonstrated that spatial movement of the molecules is a vital component of GRNs and may cause the oscillations. These numerical findings have subsequently been proved rigorously i.e. the diffusion coefficient of the protein/mRNA acts as a bifurcation parameter and gives rise to a Hopf bifurcation. In this paper we first present a model of the canonical GRN (the Hes1 protein) and show the effect of varying the spatial location of gene and protein production sites on the oscillations. We then extend the approach to examine spatio-temporal models of synthetic gene regulatory networks e.g. n-gene repressilators and activator-repressor systems.

  19. Spatio-temporal effects of low impact development practices

    Science.gov (United States)

    Gilroy, Kristin L.; McCuen, Richard H.

    2009-04-01

    SummaryThe increase in land development and urbanization experienced in the US and worldwide is causing environmental degradation. Traditional off-site stormwater management does not protect small streams. To mitigate the negative effects of land development, best management practices (BMPs) are being implemented into stormwater management policies for the purposes of controlling minor flooding and improving water quality. Unfortunately, the effectiveness of BMPs has not been extensively studied. The purpose of this research was to analyze the effects of both location and quantity of two types of BMPs: cisterns and bioretention pits. A spatio-temporal model of a microwatershed was developed to determine the effects of BMPs on single-family, townhome, and commercial lots. The effects of development and the BMPs on peak runoff rates and volumes were compared to pre-development conditions. The results show that cisterns alone are capable of controlling rooftop runoff for small storms. Both the spatial location and the volume of BMP storage on a microwatershed influences the effectiveness of BMPs. The volume of BMP storage is positively correlated to the percent reduction in the peak discharge rate and total runoff volume; however, location is a factor in the peak reduction and a maximum volume of effective storage for both hydrologic metrics does exist. These results provide guidelines for developing stormwater management policies that can potentially reduce pollution of first-order streams, lower the cost and maintenance requirements, enhance aesthetics, and increase safety.

  20. Spatio-temporal TGV denoising for ASL perfusion imaging.

    Science.gov (United States)

    Spann, Stefan M; Kazimierski, Kamil S; Aigner, Christoph S; Kraiger, Markus; Bredies, Kristian; Stollberger, Rudolf

    2017-08-15

    In arterial spin labeling (ASL) a perfusion weighted image is achieved by subtracting a label image from a control image. This perfusion weighted image has an intrinsically low signal to noise ratio and numerous measurements are required to achieve reliable image quality, especially at higher spatial resolutions. To overcome this limitation various denoising approaches have been published using the perfusion weighted image as input for denoising. In this study we propose a new spatio-temporal filtering approach based on total generalized variation (TGV) regularization which exploits the inherent information of control and label pairs simultaneously. In this way, the temporal and spatial similarities of all images are used to jointly denoise the control and label images. To assess the effect of denoising, virtual ground truth data were produced at different SNR levels. Furthermore, high-resolution in-vivo pulsed ASL data sets were acquired and processed. The results show improved image quality, quantitative accuracy and robustness against outliers compared to seven state of the art denoising approaches. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Understanding the spatiotemporal pattern of grazing cattle movement

    Science.gov (United States)

    Zhao, Kun; Jurdak, Raja

    2016-08-01

    Understanding the drivers of animal movement is significant for ecology and biology. Yet researchers have so far been unable to fully understand these drivers, largely due to low data resolution. In this study, we analyse a high-frequency movement dataset for a group of grazing cattle and investigate their spatiotemporal patterns using a simple two-state ‘stop-and-move’ mobility model. We find that the dispersal kernel in the moving state is best described by a mixture exponential distribution, indicating the hierarchical nature of the movement. On the other hand, the waiting time appears to be scale-invariant below a certain cut-off and is best described by a truncated power-law distribution, suggesting that the non-moving state is governed by time-varying dynamics. We explore possible explanations for the observed phenomena, covering factors that can play a role in the generation of mobility patterns, such as the context of grazing environment, the intrinsic decision-making mechanism or the energy status of different activities. In particular, we propose a new hypothesis that the underlying movement pattern can be attributed to the most probable observable energy status under the maximum entropy configuration. These results are not only valuable for modelling cattle movement but also provide new insights for understanding the underlying biological basis of grazing behaviour.

  2. Spatiotemporal measurement of surfactant distribution on gravity-capillary waves

    CERN Document Server

    Strickland, Stephen L; Daniels, Karen E

    2015-01-01

    Materials adsorbed to the surface of a fluid -- for instance, crude oil, biogenic slicks, or industrial/medical surfactants -- will move in response to surface waves. Due to the difficulty of non-invasive measurement of the spatial distribution of a molecular monolayer, little is known about the dynamics that couple the surface waves and the evolving density field. Here, we report measurements of the spatiotemporal dynamics of the density field of an insoluble surfactant driven by gravity-capillary waves in a shallow cylindrical container. Standing Faraday waves and traveling waves generated by the meniscus are superimposed to create a non-trivial surfactant density field. We measure both the height field of the surface using moir\\'e-imaging, and the density field of the surfactant via the fluorescence of NBD-tagged phosphatidylcholine, a lipid. Through phase-averaging stroboscopically-acquired images of the density field, we determine that the surfactant accumulates on the leading edge of the traveling menis...

  3. Spatio-temporal expression of Sox genes in murine palatogenesis.

    Science.gov (United States)

    Watanabe, Momoko; Kawasaki, Katsushige; Kawasaki, Maiko; Portaveetus, Thantrira; Oommen, Shelly; Blackburn, James; Nagai, Takahiro; Kitamura, Atsushi; Nishikawa, Atsushi; Kodama, Yasumitsu; Takagi, Ritsuo; Maeda, Takeyasu; Sharpe, Paul T; Ohazama, Atsushi

    2016-07-01

    Members of the Sox gene family play critical roles in many biological processes including organogenesis. We carried out comparative in situ hybridisation analysis of seventeen Sox genes (Sox1-14, 17, 18 and 21) during murine palatogenesis from initiation to fusion of the palatal shelves above the dorsal side of the tongue. At palatal shelf initiation (E12.5), the localized expression of six Sox genes (Sox2, 5, 6, 9, 12 and 13) was observed in the shelves, whereas Sox4 and Sox11 showed ubiquitious expression. During the down-growth of palatal shelves (E13.5), Sox4, Sox5, and Sox9 exhibited restricted expression to the interior side of the palatal shelves facing the tongue. Following elevation of the palatal shelves (E14.5), Sox2, Sox11 and Sox21 expression was present in the midline epithelial seam. We thus identify dynamic spatio-temporal expression of Sox gene family during the process of palatogenesis. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Spatial Specificity in Spatiotemporal Encoding and Fourier Imaging

    Science.gov (United States)

    Goerke, Ute

    2015-01-01

    Purpose Ultrafast imaging techniques based on spatiotemporal-encoding (SPEN), such as RASER (rapid acquisition with sequential excitation and refocusing), is a promising new class of sequences since they are largely insensitive to magnetic field variations which cause signal loss and geometric distortion in EPI. So far, attempts to theoretically describe the point-spread-function (PSF) for the original SPEN-imaging techniques have yielded limited success. To fill this gap a novel definition for an apparent PSF is proposed. Theory Spatial resolution in SPEN-imaging is determined by the spatial phase dispersion imprinted on the acquired signal by a frequency-swept excitation or refocusing pulse. The resulting signal attenuation increases with larger distance from the vertex of the quadratic phase profile. Methods Bloch simulations and experiments were performed to validate theoretical derivations. Results The apparent PSF quantifies the fractional contribution of magnetization to a voxel’s signal as a function of distance to the voxel. In contrast, the conventional PSF represents the signal intensity at various locations. Conclusion The definition of the conventional PSF fails for SPEN-imaging since only the phase of isochromats, but not the amplitude of the signal varies. The concept of the apparent PSF is shown to be generalizable to conventional Fourier- imaging techniques. PMID:26712657

  5. Workload induced spatio-temporal distortions and safety of flight

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, C.L.; Weisgerber, S.A. (Los Alamos National Lab., NM (USA); Naval Weapons Center, China Lake, CA (USA))

    1989-01-01

    A theoretical analysis of the relationship between cognitive complexity and the perception of time and distance is presented and experimentally verified. Complex tasks produce high rates of mental representation which affect the subjective sense of duration and, through the subjective time scale, the percept of distance derived from dynamic visual cues (i.e., visual cues requiring rate integration). The analysis of the interrelationship of subjective time and subjective distance yields the prediction that, as a function of cognitive complexity, distance estimates derived from dynamic visual cues will be longer than the actual distance whereas estimates based on perceived temporal duration will be shorter than the actual distance. This prediction was confirmed in an experiment in which subjects (both pilots and non-pilots) estimated distances using either temporal cues or dynamic visual cues. The distance estimation task was also combined with secondary loading tasks in order to vary the overall task complexity. The results indicated that distance estimates based on temporal cues were underestimated while estimates based on visual cues were overestimated. This spatio-temporal distortion effect increased with increases in overall task complexity. 30 refs., 6 figs., 1 tab.

  6. Spatiotemporal characteristics of motor actions by blind long jump athletes

    Science.gov (United States)

    Torralba, Miguel Angel; Padullés, José María; Losada, Jose Luis; López, Jose Luis

    2017-01-01

    Background Blind people depend on spatial and temporal representations to perform activities of daily living and compete in sport. Objective The aim of this study is to determine the spatiotemporal characteristics of long jumps performed by blind athletes and compare findings with those reported for sighted athletes. Methods We analysed a sample of 12 male athletes competing in the F11 Long Jump Finals at the Paralympic Games in London 2012. Performances were recorded using four high-speed cameras, and speeds were measured using a radar speed gun. The images were processed using validated image analysis software. Results The long jump run-up is shorter in blind athletes than in sighted athletes. We observed statistically significant differences for body centre of mass velocity and an increase in speed over the last three strides prior to take-off, contrasting with reports for sighted athletes and athletes with less severe visual impairment, who maintain or reduce their speed during the last stride. Stride length for the last three strides was the only spatial characteristic that was not significantly associated with effective jump distance. Blind long jumpers extend rather than shorten their last stride. Contact time with the take-off board is longer than that reported for sighted athletes. Conclusion The actions of blind long jumpers, unlike those without disabilities, do not vary their leg actions during the final runway approach for optimal placement on the take-off board. PMID:29018542

  7. Spatio-temporal variation in trihalomethanes in New South Wales.

    Science.gov (United States)

    Summerhayes, Richard J; Morgan, Geoffrey G; Lincoln, Douglas; Edwards, Howard P; Earnest, Arul; Rahman, Md Bayzidur; Byleveld, Paul; Cowie, Christine T; Beard, John R

    2011-11-01

    This paper describes the spatio-temporal variation of trihalomethanes in drinking water in New South Wales, Australia from 1997 to 2007 We obtained data on trihalomethanes (THMs) from two metropolitan and 13 rural water utilities and conducted a descriptive analysis of the spatial and temporal trends in THMs and the influence of season and drought. Concetrations of monthly THMs in the two metropolitan water utilities of Sydney/Illawarra (mean 66.8 μg/L) and Hunter (mean 62.7 μg/L) were similar compared to the considerable variation between rural water utilities (range in mean THMs: 14.5-330.7 μg/L). Chloroform was the predominate THM in two-thirds of the rural water utilities. Higher concentrations of THMs were found in chlorinated water distribution systems compared to chloraminated systems, and in distribution systems sourced from surface water compared to ground water or mixed surface and ground water. Ground water sourced supplies had a greater proportion of brominated THMs than surface water sourced supplies. There was substantial variation in concentration of THMs between seasons and between periods of drought or no drought. There was a moderate correlation between heavy rainfall and elevated concentrations of THMs. There is considerable spatial and temporal variation in THMs amongst New South Wales water utilities and these variations are likely related to water source, treatment processes, catchments, drought and seasonal factors. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. The quantum basis of spatiotemporality in perception and consciousness.

    Science.gov (United States)

    Igamberdiev, Abir U; Shklovskiy-Kordi, Nikita E

    2017-11-01

    Living systems inhabit the area of the world which is shaped by the predictable space-time of physical objects and forces that can be incorporated into their perception pattern. The process of selecting a "habitable" space-time is the internal quantum measurement in which living systems become embedded into the environment that supports their living state. This means that living organisms choose a coordinate system in which the influence of measurement is minimal. We discuss specific roles of biological macromolecules, in particular of the cytoskeleton, in shaping perception patterns formed in the internal measurement process. Operation of neuron is based on the transmission of signals via cytoskeleton where the digital output is generated that can be decoded through a reflective action of the perceiving agent. It is concluded that the principle of optimality in biology as formulated by Liberman et al. (BioSystems 22, 135-154, 1989) is related to the establishment of spatiotemporal patterns that are maximally predictable and can hold the living state for a prolonged time. This is achieved by the selection of a habitable space approximated to the conditions described by classical physics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Spatiotemporal expression of Ski after rat spinal cord injury.

    Science.gov (United States)

    Zhou, Kaisheng; Nan, Wei; Feng, Dongliang; Yi, Zhigang; Zhu, Yandong; Long, Zaiyun; Li, Sen; Zhang, Haihong; Wu, Yamin

    2017-02-08

    Ski is an evolutionarily conserved protein and widely participates in the regulation of various pathological and physiological processes such as wound healing, liver regeneration, development of the embryonic nervous system, muscle differentiation, and progression of many kinds of tumors. However, the distribution and function of Ski in central nervous system lesion and disease remain unclear. In this study, we investigated the spatiotemporal expression of Ski in a spinal cord injury (SCI) model in adult rats. Western Blot analysis indicated that Ski was expressed in both normal and injured spinal cord, and showed a significant upregulation after SCI compared with the sham group. Double-labeled immunofluorescence staining showed that Ski was significantly expressed in astrocytes, but not in the neurons. Western Blot analyses of glial fibrillary acidic protein (GFAP) and BBB scores were carried out and correlation analysis showed a positive correlation between them. In addition, the relative expression level of Ski was also positively correlated with the relative expression level of GFAP. Moreover, the conspicuous co-expression band of Ski and GFAP at the lesion border was found in the results of immunofluorescence staining combined with the pattern of glial scar formation reflected by H&E staining; in addition, it was found that Ski was also highly associated with glial scar. On the basis of our data, we speculated that Ski might play an important role in the process of reactive astrogliosis after SCI and our study might provide a basis for further study on the detailed role of Ski in astrocytes.

  10. Spatiotemporal Recurrent Convolutional Networks for Traffic Prediction in Transportation Networks

    Directory of Open Access Journals (Sweden)

    Haiyang Yu

    2017-06-01

    Full Text Available Predicting large-scale transportation network traffic has become an important and challenging topic in recent decades. Inspired by the domain knowledge of motion prediction, in which the future motion of an object can be predicted based on previous scenes, we propose a network grid representation method that can retain the fine-scale structure of a transportation network. Network-wide traffic speeds are converted into a series of static images and input into a novel deep architecture, namely, spatiotemporal recurrent convolutional networks (SRCNs, for traffic forecasting. The proposed SRCNs inherit the advantages of deep convolutional neural networks (DCNNs and long short-term memory (LSTM neural networks. The spatial dependencies of network-wide traffic can be captured by DCNNs, and the temporal dynamics can be learned by LSTMs. An experiment on a Beijing transportation network with 278 links demonstrates that SRCNs outperform other deep learning-based algorithms in both short-term and long-term traffic prediction.

  11. Spatiotemporal Recurrent Convolutional Networks for Traffic Prediction in Transportation Networks

    Science.gov (United States)

    Yu, Haiyang; Wu, Zhihai; Wang, Shuqin; Wang, Yunpeng; Ma, Xiaolei

    2017-01-01

    Predicting large-scale transportation network traffic has become an important and challenging topic in recent decades. Inspired by the domain knowledge of motion prediction, in which the future motion of an object can be predicted based on previous scenes, we propose a network grid representation method that can retain the fine-scale structure of a transportation network. Network-wide traffic speeds are converted into a series of static images and input into a novel deep architecture, namely, spatiotemporal recurrent convolutional networks (SRCNs), for traffic forecasting. The proposed SRCNs inherit the advantages of deep convolutional neural networks (DCNNs) and long short-term memory (LSTM) neural networks. The spatial dependencies of network-wide traffic can be captured by DCNNs, and the temporal dynamics can be learned by LSTMs. An experiment on a Beijing transportation network with 278 links demonstrates that SRCNs outperform other deep learning-based algorithms in both short-term and long-term traffic prediction. PMID:28672867

  12. How spatio-temporal habitat connectivity affects amphibian genetic structure

    Science.gov (United States)

    Watts, Alexander G.; Schlichting, P; Billerman, S; Jesmer, B; Micheletti, S; Fortin, M.-J.; Funk, W.C.; Hapeman, P; Muths, Erin L.; Murphy, M.A.

    2015-01-01

    Heterogeneous landscapes and fluctuating environmental conditions can affect species dispersal, population genetics, and genetic structure, yet understanding how biotic and abiotic factors affect population dynamics in a fluctuating environment is critical for species management. We evaluated how spatio-temporal habitat connectivity influences dispersal and genetic structure in a population of boreal chorus frogs (Pseudacris maculata) using a landscape genetics approach. We developed gravity models to assess the contribution of various factors to the observed genetic distance as a measure of functional connectivity. We selected (a) wetland (within-site) and (b) landscape matrix (between-site) characteristics; and (c) wetland connectivity metrics using a unique methodology. Specifically, we developed three networks that quantify wetland connectivity based on: (i) P. maculata dispersal ability, (ii) temporal variation in wetland quality, and (iii) contribution of wetland stepping-stones to frog dispersal. We examined 18 wetlands in Colorado, and quantified 12 microsatellite loci from 322 individual frogs. We found that genetic connectivity was related to topographic complexity, within- and between-wetland differences in moisture, and wetland functional connectivity as contributed by stepping-stone wetlands. Our results highlight the role that dynamic environmental factors have on dispersal-limited species and illustrate how complex asynchronous interactions contribute to the structure of spatially-explicit metapopulations.

  13. The Phylogeographic and Spatiotemporal Spread of HCV in Pakistani Population.

    Directory of Open Access Journals (Sweden)

    Noor-Ul-Huda Ghori

    Full Text Available Hepatitis C Virus (HCV is the most prevalent human pathogen in Pakistan and is the major cause of liver cirrhosis and hepatocellular carcinoma in infected patients. It has shifted from being hypo-endemic to being hyper-endemic. There was no information about the origin and evolution of the local variants. Here we use newly developed phyloinformatic methods of sequence analysis to conduct the first comprehensive investigation of the evolutionary and biogeographic history in unprecedented detail and breadth. Considering evolutionary rate and molecular-clock hypothesis in context, we reconstructed the spatiotemporal spread of HCV in the whole territory of its circulation using a combination of Bayesian MCMC methods utilizing all sequences available in GenBank. Comparative analysis were performed and were addressed. Whole genome and individual gene analysis have shown that sub-types 1a, 1b and 3a are recognized as epidemic strains and are distributed globally. Here we confirm that the origin of HCV 3a genotypes is in South Asia and HCV has evolved in the region to become stably adapted to the host environment.

  14. Systemic risk and spatiotemporal dynamics of the US housing market

    Science.gov (United States)

    Meng, Hao; Xie, Wen-Jie; Jiang, Zhi-Qiang; Podobnik, Boris; Zhou, Wei-Xing; Stanley, H. Eugene

    2014-01-01

    Housing markets play a crucial role in economies and the collapse of a real-estate bubble usually destabilizes the financial system and causes economic recessions. We investigate the systemic risk and spatiotemporal dynamics of the US housing market (1975-2011) at the state level based on the Random Matrix Theory (RMT). We identify richer economic information in the largest eigenvalues deviating from RMT predictions for the housing market than for stock markets and find that the component signs of the eigenvectors contain either geographical information or the extent of differences in house price growth rates or both. By looking at the evolution of different quantities such as eigenvalues and eigenvectors, we find that the US housing market experienced six different regimes, which is consistent with the evolution of state clusters identified by the box clustering algorithm and the consensus clustering algorithm on the partial correlation matrices. We find that dramatic increases in the systemic risk are usually accompanied by regime shifts, which provide a means of early detection of housing bubbles.

  15. Spatio-Temporal Human Grip Force Analysis via Sensor Arrays

    Science.gov (United States)

    Kutz, Dieter F.; Wölfel, Alexander; Meindl, Tobias; Timmann, Dagmar; Kolb, Florian P.

    2009-01-01

    This study describes a technique for measuring human grip forces exerted on a cylindrical object via a sensor array. Standardised resistor-based pressure sensor arrays for industrial and medical applications have been available for some time. We used a special 20 mm diameter grip rod that subjects could either move actively with their fingers in the horizontal direction or exert reactive forces against opposing forces generated in the rod by a linear motor. The sensor array film was attached to the rod by adhesive tape and covered approximately 45 cm2 of the rod surface. The sensor density was 4/cm2 with each sensor having a force resolution of 0.1 N. A scan across all sensors resulted in a corresponding frame containing force values at a frame repetition rate of 150/s. The force value of a given sensor was interpreted as a pixel value resulting in a false-colour image. Based on remote sensed image analysis an algorithm was developed to distinguish significant force-representing pixels from those affected by noise. This allowed tracking of the position of identified fingers in subsequent frames such that spatio-temporal grip force profiles for individual fingers could be derived. Moreover, the algorithm allowed simultaneous measurement of forces exerted without any constraints on the number of fingers or on the position of the fingers. The system is thus well suited for basic and clinical research in human physiology as well as for studies in psychophysics. PMID:22454588

  16. Spatio-Temporal Human Grip Force Analysis via Sensor Arrays

    Directory of Open Access Journals (Sweden)

    Florian P. Kolb

    2009-08-01

    Full Text Available This study describes a technique for measuring human grip forces exerted on a cylindrical object via a sensor array. Standardised resistor-based pressure sensor arrays for industrial and medical applications have been available for some time. We used a special 20 mm diameter grip rod that subjects could either move actively with their fingers in the horizontal direction or exert reactive forces against opposing forces generated in the rod by a linear motor. The sensor array film was attached to the rod by adhesive tape and covered approximately 45 cm2 of the rod surface. The sensor density was 4/cm2 with each sensor having a force resolution of 0.1 N. A scan across all sensors resulted in a corresponding frame containing force values at a frame repetition rate of 150/s. The force value of a given sensor was interpreted as a pixel value resulting in a false-colour image. Based on remote sensed image analysis an algorithm was developed to distinguish significant force-representing pixels from those affected by noise. This allowed tracking of the position of identified fingers in subsequent frames such that spatio-temporal grip force profiles for individual fingers could be derived. Moreover, the algorithm allowed simultaneous measurement of forces exerted without any constraints on the number of fingers or on the position of the fingers. The system is thus well suited for basic and clinical research in human physiology as well as for studies in psychophysics.

  17. Spatiotemporal inpainting for recovering texture maps of occluded building facades.

    Science.gov (United States)

    Korah, Thommen; Rasmussen, Christopher

    2007-09-01

    We present a technique for constructing a "clean" texture map of a partially occluded building facade from a series of images taken from a moving camera. Building regions blocked by trees, signs, people, and other foreground objects in a minority of views can be recovered via temporal median filtering on a registered image mosaic of the planar facade. However, when such areas are occluded in the majority of camera views, appearance information from other visible portions of the facade provides a critical cue to correctly complete the mosaic. In this paper, we apply a robust measure of spread to infer whether a particular mosaic pixel is occluded in a majority of views, and introduce a novel spatiotemporal timeline-based inpainting algorithm that uses appearance and motion cues in order to fill the texture map in majority-occluded regions. We describe methods for automatically training appearance-based classifiers from a coarse motion-based segmentation to efficiently recognize foreground and background patches in static imagery. Results of recovered building facades are shown for various sequences.

  18. Spatio-temporal image inpainting for video applications

    Directory of Open Access Journals (Sweden)

    Voronin Viacheslav

    2017-01-01

    Full Text Available Video inpainting or completion is a vital video improvement technique used to repair or edit digital videos. This paper describes a framework for temporally consistent video completion. The proposed method allows to remove dynamic objects or restore missing or tainted regions presented in a video sequence by utilizing spatial and temporal information from neighboring scenes. Masking algorithm is used for detection of scratches or damaged portions in video frames. The algorithm iteratively performs the following operations: achieve frame; update the scene model; update positions of moving objects; replace parts of the frame occupied by the objects marked for remove by using a background model. In this paper, we extend an image inpainting algorithm based texture and structure reconstruction by incorporating an improved strategy for video. Our algorithm is able to deal with a variety of challenging situations which naturally arise in video inpainting, such as the correct reconstruction of dynamic textures, multiple moving objects and moving background. Experimental comparisons to state-of-the-art video completion methods demonstrate the effectiveness of the proposed approach. It is shown that the proposed spatio-temporal image inpainting method allows restoring a missing blocks and removing a text from the scenes on videos.

  19. Investigation of spatiotemporal relationship between dengue fever and drought

    Science.gov (United States)

    Lee, Chieh-Han; Yu, Hwa-Lung

    2016-04-01

    Dengue Fever is a vector-borne disease that is transmitted between human and mosquitos in tropical and sub-tropical regions. Previous studies have found significant relationship between the epidemic of dengue cases and climate variables, especially temperature and precipitation. Besides, the natural phenomena (e.g., drought) are considered that significantly drop the number of dengue cases by killing vector's breeding environment. However, in Kaohsiung City, Taiwan, there are evidences that the temporal pattern of dengue is correlated to drought events. Kaohsiung City experienced two main dengue outbreaks in 2002 and 2014 that both years were confirmed with serious drought. Especially in 2014, Kaohsiung City was suffered from extremely dengue outbreak in 2014 that reported the highest number of dengue cases in the history. Otherwise, another nearby city, Tainan City, had reported the biggest outbreak in 2015. This study constructs the spatiotemporal model of dengue incidences and index of drought events (Standardized Precipitation Index, SPI) based on the distributed lag nonlinear model (DLNM). Other meteorological measures are also included in the analysis.

  20. Work Experience and Work Involvement.

    Science.gov (United States)

    Lorence, Jon; Mortimer, Jeylan T.

    1981-01-01

    Examines the interrelations of work experience and psychological involvement in work among male college graduates over a 10-year period. Both the occupational socialization and the occupational selection hypotheses are supported by the data analysis. (Author/JOW)

  1. The spatiotemporal variation analysis of virtual water for agriculture and livestock husbandry: A study for Jilin Province in China.

    Science.gov (United States)

    Ma, Xiaolei; Ma, Yanji

    2017-05-15

    With the rapid development of economic, water crisis is becoming more and more serious and would be an important obstacle to the sustainable development of society. Virtual water theory and its applications in agriculture can provide important strategies for realizing the reasonable utilization and sustainable development of water resources. Using the Penman-Monteith model and Theil index combining the CROPWAT software, this work takes Jilin Province as study area quantifying the virtual water content of agriculture and livestock husbandry and giving a comprehensive evaluation of their spatiotemporal structure evolution. This study aims to help make clear the water consumption of agriculture and livestock husbandry, and offer advice on rational water utilization and agricultural structure adjustment. The results show that the total virtual water (TVW) proportion of agriculture presents a gradual growth trend while that of livestock husbandry reduces during the study period. In space, central Jilin shows the highest virtual water content of agriculture as well as livestock husbandry, the TVW in central Jilin is about 35.8billionm 3 . The TVW of maize is highest among six studied crops, and the cattle shows the highest TVW in the four kinds of animals. The distribution of TVW calculated by us and the distribution of actual water resources have remarkable difference, which leads to the increase of water consumption and cost of agricultural production. Finally, we discuss the driving force of the spatiotemporal variation of the TVW for agriculture and livestock husbandry, and also give some advises for the planting structural adjustment. This work is helpful for the sustainable development of agricultural and livestock husbandry and realizing efficient utilization of water resources. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Spatiotemporal variability and environmental factors of harmful algal blooms (HABs over western Lake Erie.

    Directory of Open Access Journals (Sweden)

    Di Tian

    Full Text Available Over the past decades, numerous studies have been carried out in understanding causes of Harmful Algal Blooms (HABs and their dynamics, yielding great knowledge in this field. Lake Erie, the fourth-largest lake of the five Great Lake, is among those highly vulnerable to the impacts of HABs and has received substantial attention from the public, water management sectors, and academic field. Building upon previous work, this study aims to characterize spatiotemporal variability of Chlorophyll a (Chl-a, which is an important indicator of HABs, and to explore relative importance of environmental factors associated with HABs in the west Lake Erie. Ten years of biweekly Chl-a information over western Lake Erie were derived from MERIS data at the pixel scale. Based on the MERIS-derived information high concentrations of Chl-a were observed in the south near shore area in spring and fall and in the west corner area of western Lake Erie in all three seasons except winter. Wavelet analysis suggested that the 0.5- and 1-year periods were dominant modes for the Chl-a series. The Multivariate Adaptive Regression Splines (MARS analysis was performed to explore factors associated with the dynamics of Chl-a. The results suggested that overall both phenological (e.g. wind and ecological (e.g. nutrient levels factors exhibited significant correlations with the remotely-sensed imagery based observations of Chl-a despite spatial and temporal variations. The important phenological and ecological factors include solar radiation and wind speed in spring, water temperature, solar radiation, and total Kjeldahl nitrogen concentration in summer, wind speed in fall, and water temperature and streamflow in winter. Both consistency and differences of findings of the study with others in the region may suggest strengths and limitations of the remotely sensed imagery-based analysis, offering valuable information for future work.

  3. Brain Network Activation Analysis Utilizing Spatiotemporal Features for Event Related Potentials Classification

    Directory of Open Access Journals (Sweden)

    Yaki Stern

    2016-12-01

    Full Text Available The purpose of this study was to introduce an improved tool for automated classification of event-related potentials (ERPs using spatiotemporally parcellated events incorporated into a functional brain network activation (BNA analysis. The auditory oddball ERP paradigm was selected to demonstrate and evaluate the improved tool. Methods: The ERPs of each subject were decomposed into major dynamic spatiotemporal events. Then, a set of spatiotemporal events representing the group was generated by aligning and clustering the spatiotemporal events of all individual subjects. The temporal relationship between the common group events generated a network, which is the spatiotemporal reference BNA model. Scores were derived by comparing each subject’s spatiotemporal events to the reference BNA model and were then entered into a support vector machine classifier to classify subjects into relevant subgroups. The reliability of the BNA scores (test-retest repeatability using intraclass correlation and their utility as a classification tool were examined in the context of Target-Novel classification. Results: BNA intraclass correlation values of repeatability ranged between 0.51 and 0.82 for the known ERP components N100, P200 and P300. Classification accuracy was high when the trained data were validated on the same subjects for different visits (AUCs 0.93 and 0.95. The classification accuracy remained high for a test group recorded at a different clinical center with a different recording system (AUCs 0.81, 0.85 for 2 visits. Conclusion: The improved spatiotemporal BNA analysis demonstrates high classification accuracy. The BNA analysis method holds promise as a tool for diagnosis, follow-up and drug development associated with different neurological conditions.

  4. Spatiotemporal Psychopathology II: How does a psychopathology of the brain's resting state look like? Spatiotemporal approach and the history of psychopathology.

    Science.gov (United States)

    Northoff, Georg

    2016-01-15

    Psychopathology as the investigation and classification of experience, behavior and symptoms in psychiatric patients is an old discipline that ranges back to the end of the 19th century. Since then different approaches to psychopathology have been suggested. Recent investigations showing abnormalities in the brain on different levels raise the question how the gap between brain and psyche, between neural abnormalities and alteration in experience and behavior can be bridged. Historical approaches like descriptive (Jaspers) and structural (Minkoswki) psychopathology as well as the more current phenomenological psychopathology (Paarnas, Fuchs, Sass, Stanghellini) remain on the side of the psyche giving detailed description of the phenomenal level of experience while leaving open the link to the brain. In contrast, the recently introduced Research Domain Classification (RDoC) aims at explicitly linking brain and psyche by starting from so-called 'neuro-behavioral constructs'. How does Spatiotemporal Psychopathology, as demonstrated in the first paper on depression, stand in relation to these approaches? In a nutshell, Spatiotemporal Psychopathology aims to bridge the gap between brain and psyche. Specifically, as demonstrated in depression in the first paper, the focus is on the spatiotemporal features of the brain's intrinsic activity and how they are transformed into corresponding spatiotemporal features in experience on the phenomenal level and behavioral changes, which can well account for the symptoms in these patients. This second paper focuses on some of the theoretical background assumptions in Spatiotemporal Psychopathology by directly comparing it to descriptive, structural, and phenomenological psychopathology as well as to RDoC. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Ozone Concentration Prediction via Spatiotemporal Autoregressive Model With Exogenous Variables

    Science.gov (United States)

    Kamoun, W.; Senoussi, R.

    2009-04-01

    Forecast of environmental variables are nowadays of main concern for public health or agricultural management. In this context a large literature is devoted to spatio-temporal modelling of these variables using different statistical approaches. However, most of studies ignored the potential contribution of local (e.g. meteorological and/or geographical) covariables as well as the dynamical characteristics of observations. In this study, we present a spatiotemporal short term forecasting model for ozone concentration based on regularly observed covariables in predefined geographical sites. Our driving system simply combines a multidimensional second order autoregressive structured process with a linear regression model over influent exogenous factors and reads as follows: ‘2 ‘q j Z (t) = A (Î&,cedil;D )Ã- [ αiZ(t- i)]+ B (Î&,cedil;D )Ã- [ βjX (t)]+ ɛ(t) i=1 j=1 Z(t)=(Z1(t),…,Zn(t)) represents the vector of ozone concentration at time t of the n geographical sites, whereas Xj(t)=(X1j(t),…,Xnj(t)) denotes the jth exogenous variable observed over these sites. The nxn matrix functions A and B account for the spatial relationships between sites through the inter site distance matrix D and a vector parameter Î&.cedil; Multidimensional white noise ɛ is assumed to be Gaussian and spatially correlated but temporally independent. A covariance structure of Z that takes account of noise spatial dependences is deduced under a stationary hypothesis and then included in the likelihood function. Statistical model and estimation procedure: Contrarily to the widely used choice of a {0,1}-valued neighbour matrix A, we put forward two more natural choices of exponential or power decay. Moreover, the model revealed enough stable to readily accommodate the crude observations without the usual tedious and somewhat arbitrarily variable transformations. Data set and preliminary analysis: In our case, ozone variable represents here the daily maximum ozone

  6. Spatiotemporal Variation in Mangrove Chlorophyll Concentration Using Landsat 8

    Directory of Open Access Journals (Sweden)

    Julio Pastor-Guzman

    2015-11-01

    Full Text Available There is a need to develop indicators of mangrove condition using remotely sensed data. However, remote estimation of leaf and canopy biochemical properties and vegetation condition remains challenging. In this paper, we (i tested the performance of selected hyperspectral and broad band indices to predict chlorophyll concentration (CC on mangrove leaves and (ii showed the potential of Landsat 8 for estimation of mangrove CC at the landscape level. Relative leaf CC and leaf spectral response were measured at 12 Elementary Sampling Units (ESU distributed along the northwest coast of the Yucatan Peninsula, Mexico. Linear regression models and coefficients of determination were computed to measure the association between CC and spectral response. At leaf level, the narrow band indices with the largest correlation with CC were Vogelmann indices and the MTCI (R2 > 0.5. Indices with spectral bands around the red edge (705–753 nm were more sensitive to mangrove leaf CC. At the ESU level Landsat 8 NDVI green, which uses the green band in its formulation explained most of the variation in CC (R2 > 0.8. Accuracy assessment between estimated CC and observed CC using the leave-one-out cross-validation (LOOCV method yielded a root mean squared error (RMSE = 15 mg·cm−2, and R2 = 0.703. CC maps showing the spatiotemporal variation of CC at landscape scale were created using the linear model. Our results indicate that Landsat 8 NDVI green can be employed to estimate CC in large mangrove areas where ground networks cannot be applied, and mapping techniques based on satellite data, are necessary. Furthermore, using upcoming technologies that will include two bands around the red edge such as Sentinel 2 will improve mangrove monitoring at higher spatial and temporal resolutions.

  7. Spatiotemporal Variations and Driving Factors of Air Pollution in China.

    Science.gov (United States)

    Zhan, Dongsheng; Kwan, Mei-Po; Zhang, Wenzhong; Wang, Shaojian; Yu, Jianhui

    2017-12-08

    In recent years, severe and persistent air pollution episodes in China have drawn wide public concern. Based on ground monitoring air quality data collected in 2015 in Chinese cities above the prefectural level, this study identifies the spatiotemporal variations of air pollution and its associated driving factors in China using descriptive statistics and geographical detector methods. The results show that the average air pollution ratio and continuous air pollution ratio across Chinese cities in 2015 were 23.1 ± 16.9% and 16.2 ± 14.8%. The highest levels of air pollution ratio and continuous air pollution ratio were observed in northern China, especially in the Bohai Rim region and Xinjiang province, and the lowest levels were found in southern China. The average and maximum levels of continuous air pollution show distinct spatial variations when compared with those of the continuous air pollution ratio. Monthly changes in both air pollution ratio and continuous air pollution ratio have a U-shaped variation, indicating that the highest levels of air pollution occurred in winter and the lowest levels happened in summer. The results of the geographical detector model further reveal that the effect intensity of natural factors on the spatial disparity of the air pollution ratio is greater than that of human-related factors. Specifically, among natural factors, the annual average temperature, land relief, and relative humidity have the greatest and most significant negative effects on the air pollution ratio, whereas human factors such as population density, the number of vehicles, and Gross Domestic Product (GDP) witness the strongest and most significant positive effects on air pollution ratio.

  8. Basic instinct undressed: early spatiotemporal processing for primary sexual characteristics.

    Directory of Open Access Journals (Sweden)

    Lore B Legrand

    Full Text Available This study investigates the spatiotemporal dynamics associated with conscious and non-conscious processing of naked and dressed human bodies. To this effect, stimuli of naked men and women with visible primary sexual characteristics, as well as dressed bodies, were presented to 20 heterosexual male and female participants while acquiring high resolution EEG data. The stimuli were either consciously detectable (supraliminal presentations or were rendered non-conscious through backward masking (subliminal presentations. The N1 event-related potential component was significantly enhanced in participants when they viewed naked compared to dressed bodies under supraliminal viewing conditions. More importantly, naked bodies of the opposite sex produced a significantly greater N1 component compared to dressed bodies during subliminal presentations, when participants were not aware of the stimulus presented. A source localization algorithm computed on the N1 showed that the response for naked bodies in the supraliminal viewing condition was stronger in body processing areas, primary visual areas and additional structures related to emotion processing. By contrast, in the subliminal viewing condition, only visual and body processing areas were found to be activated. These results suggest that naked bodies and primary sexual characteristics are processed early in time (i.e., <200 ms and activate key brain structures even when they are not consciously detected. It appears that, similarly to what has been reported for emotional faces, sexual features benefit from automatic and rapid processing, most likely due to their high relevance for the individual and their importance for the species in terms of reproductive success.

  9. Charging stations location model based on spatiotemporal electromobility use patterns

    Science.gov (United States)

    Pagany, Raphaela; Marquardt, Anna; Zink, Roland

    2016-04-01

    One of the major challenges for mainstream adoption of electric vehicles is the provision of infrastructure for charging the batteries of the vehicles. The charging stations must not only be located dense enough to allow users to complete their journeys, but the electric energy must also be provided from renewable sources in order to truly offer a transportation with less CO2 emissions. The examination of potential locations for the charging of electric vehicles can facilitate the adaption of electromobility and the integration of electronic vehicles in everyday life. A geographic information system (GIS) based model for optimal location of charging stations in a small and regional scale is presented. This considers parameters such as the forecast of electric vehicle use penetration, the relevant weight of diverse point of interests and the distance between parking area and destination for different vehicle users. In addition to the spatial scale the temporal modelling of the energy demand at the different charging locations has to be considerate. Depending on different user profiles (commuters, short haul drivers etc.) the frequency of charging vary during the day, the week and the year. In consequence, the spatiotemporal variability is a challenge for a reliable energy supply inside a decentralized renewable energy system. The presented model delivers on the one side the most adequate identified locations for charging stations and on the other side the interaction between energy supply and demand for electromobility under the consideration of temporal aspects. Using ESRI ArcGIS Desktop, first results for the case study region of Lower Bavaria are generated. The aim of the concept is to keep the model transferable to other regions and also open to integrate further and more detailed user profiles, derived from social studies about i.e. the daily behavior and the perception of electromobility in a next step.

  10. The timing and spatiotemporal patterning of Neanderthal disappearance.

    Science.gov (United States)

    Higham, Tom; Douka, Katerina; Wood, Rachel; Ramsey, Christopher Bronk; Brock, Fiona; Basell, Laura; Camps, Marta; Arrizabalaga, Alvaro; Baena, Javier; Barroso-Ruíz, Cecillio; Bergman, Christopher; Boitard, Coralie; Boscato, Paolo; Caparrós, Miguel; Conard, Nicholas J; Draily, Christelle; Froment, Alain; Galván, Bertila; Gambassini, Paolo; Garcia-Moreno, Alejandro; Grimaldi, Stefano; Haesaerts, Paul; Holt, Brigitte; Iriarte-Chiapusso, Maria-Jose; Jelinek, Arthur; Jordá Pardo, Jesús F; Maíllo-Fernández, José-Manuel; Marom, Anat; Maroto, Julià; Menéndez, Mario; Metz, Laure; Morin, Eugène; Moroni, Adriana; Negrino, Fabio; Panagopoulou, Eleni; Peresani, Marco; Pirson, Stéphane; de la Rasilla, Marco; Riel-Salvatore, Julien; Ronchitelli, Annamaria; Santamaria, David; Semal, Patrick; Slimak, Ludovic; Soler, Joaquim; Soler, Narcís; Villaluenga, Aritza; Pinhasi, Ron; Jacobi, Roger

    2014-08-21

    The timing of Neanderthal disappearance and the extent to which they overlapped with the earliest incoming anatomically modern humans (AMHs) in Eurasia are key questions in palaeoanthropology. Determining the spatiotemporal relationship between the two populations is crucial if we are to understand the processes, timing and reasons leading to the disappearance of Neanderthals and the likelihood of cultural and genetic exchange. Serious technical challenges, however, have hindered reliable dating of the period, as the radiocarbon method reaches its limit at ∼50,000 years ago. Here we apply improved accelerator mass spectrometry (14)C techniques to construct robust chronologies from 40 key Mousterian and Neanderthal archaeological sites, ranging from Russia to Spain. Bayesian age modelling was used to generate probability distribution functions to determine the latest appearance date. We show that the Mousterian ended by 41,030-39,260 calibrated years bp (at 95.4% probability) across Europe. We also demonstrate that succeeding 'transitional' archaeological industries, one of which has been linked with Neanderthals (Châtelperronian), end at a similar time. Our data indicate that the disappearance of Neanderthals occurred at different times in different regions. Comparing the data with results obtained from the earliest dated AMH sites in Europe, associated with the Uluzzian technocomplex, allows us to quantify the temporal overlap between the two human groups. The results reveal a significant overlap of 2,600-5,400 years (at 95.4% probability). This has important implications for models seeking to explain the cultural, technological and biological elements involved in the replacement of Neanderthals by AMHs. A mosaic of populations in Europe during the Middle to Upper Palaeolithic transition suggests that there was ample time for the transmission of cultural and symbolic behaviours, as well as possible genetic exchanges, between the two groups.

  11. Social biases determine spatiotemporal sparseness of ciliate mating heuristics.

    Science.gov (United States)

    Clark, Kevin B

    2012-01-01

    Ciliates become highly social, even displaying animal-like qualities, in the joint presence of aroused conspecifics and nonself mating pheromones. Pheromone detection putatively helps trigger instinctual and learned courtship and dominance displays from which social judgments are made about the availability, compatibility, and fitness representativeness or likelihood of prospective mates and rivals. In earlier studies, I demonstrated the heterotrich Spirostomum ambiguum improves mating competence by effecting preconjugal strategies and inferences in mock social trials via behavioral heuristics built from Hebbian-like associative learning. Heuristics embody serial patterns of socially relevant action that evolve into ordered, topologically invariant computational networks supporting intra- and intermate selection. S. ambiguum employs heuristics to acquire, store, plan, compare, modify, select, and execute sets of mating propaganda. One major adaptive constraint over formation and use of heuristics involves a ciliate's initial subjective bias, responsiveness, or preparedness, as defined by Stevens' Law of subjective stimulus intensity, for perceiving the meaningfulness of mechanical pressures accompanying cell-cell contacts and additional perimating events. This bias controls durations and valences of nonassociative learning, search rates for appropriate mating strategies, potential net reproductive payoffs, levels of social honesty and deception, successful error diagnosis and correction of mating signals, use of insight or analysis to solve mating dilemmas, bioenergetics expenditures, and governance of mating decisions by classical or quantum statistical mechanics. I now report this same social bias also differentially affects the spatiotemporal sparseness, as measured with metric entropy, of ciliate heuristics. Sparseness plays an important role in neural systems through optimizing the specificity, efficiency, and capacity of memory representations. The present

  12. Spatiotemporal patterns, triggers and anatomies of seismically detected rockfalls

    Science.gov (United States)

    Dietze, Michael; Turowski, Jens M.; Cook, Kristen L.; Hovius, Niels

    2017-11-01

    Rockfalls are a ubiquitous geomorphic process and a natural hazard in steep landscapes across the globe. Seismic monitoring can provide precise information on the timing, location and event anatomy of rockfalls, which are parameters that are otherwise hard to constrain. By pairing data from 49 seismically detected rockfalls in the Lauterbrunnen Valley in the Swiss Alps with auxiliary meteorologic and seismic data of potential triggers during autumn 2014 and spring 2015, we are able to (i) analyse the evolution of single rockfalls and their common properties, (ii) identify spatial changes in activity hotspots (iii) and explore temporal activity patterns on different scales ranging from months to minutes to quantify relevant trigger mechanisms. Seismic data allow for the classification of rockfall activity into two distinct phenomenological types. The signals can be used to discern multiple rock mass releases from the same spot, identify rockfalls that trigger further rockfalls and resolve modes of subsequent talus slope activity. In contrast to findings based on discontinuous methods with integration times of several months, rockfall in the monitored limestone cliff is not spatially uniform but shows a systematic downward shift of a rock mass release zone following an exponential law, most likely driven by a continuously lowering water table. Freeze-thaw transitions, approximated at first order from air temperature time series, account for only 5 out of the 49 rockfalls, whereas 19 rockfalls were triggered by rainfall events with a peak lag time of 1 h. Another 17 rockfalls were triggered by diurnal temperature changes and occurred during the coldest hours of the day and during the highest temperature change rates. This study is thus the first to show direct links between proposed rockfall triggers and the spatiotemporal distribution of rockfalls under natural conditions; it extends existing models by providing seismic observations of the rockfall process prior to

  13. Comparison of two kriging interpolation methods applied to spatiotemporal rainfall

    Science.gov (United States)

    Kebaili Bargaoui, Zoubeida; Chebbi, Afef

    2009-02-01

    SummaryThe variogram structure is an effective tool in order to appraise the rainfall spatial variability. In areas with disperse raingauge network, this paper suggests a 3-D estimation of the variogram, as alternative to the classical 2-D approach for spatiotemporal rainfall analysis. The context deals with the estimation of the spatial variability of maximum intensity of rainfall for a given duration δ. Hence, a 3-coordinate vector (location - rainfall duration - rainfall intensity) is associated to each monitoring location rather than the two coordinate vector, based only on the location in relation to intensity subject to duration. A set of averaging time intervals is taken into account ( δ ranging from 5 min to 2 h). The advantage of the 3-D approach is that it results on a standardized variogram which uniquely characterizes the rainfall event. On the contrary, for the 2-D approach, variograms are subject to intensity duration. The kriging with external drift is performed to make the spatial interpolations and to compute the kriging variance maps. A full comparison of the accuracy of both methods (2-D, 3-D) using cross-validation scheme, shows that the 3-D kriging leads to significantly lower prediction errors than the classical 2-D kriging. It is further suggested to quantify the effect of 3-D and 2-D kriging on the areal rainfall distribution and on the standard deviation of the kriging error SDKE. It is noticed that the 3-D SDKE field displays an empirical distribution which represents a median position among the 2-D distributions corresponding to SDKE ( δ) fields. On the other hand, results are compared to those obtained through ordinary kriging. In the 3-D approach, cross-validation performances and SDKE maps are found to be less sensitive to the kriging method.

  14. Simple models for studying complex spatiotemporal patterns of animal behavior

    Science.gov (United States)

    Tyutyunov, Yuri V.; Titova, Lyudmila I.

    2017-06-01

    Minimal mathematical models able to explain complex patterns of animal behavior are essential parts of simulation systems describing large-scale spatiotemporal dynamics of trophic communities, particularly those with wide-ranging species, such as occur in pelagic environments. We present results obtained with three different modelling approaches: (i) an individual-based model of animal spatial behavior; (ii) a continuous taxis-diffusion-reaction system of partial-difference equations; (iii) a 'hybrid' approach combining the individual-based algorithm of organism movements with explicit description of decay and diffusion of the movement stimuli. Though the models are based on extremely simple rules, they all allow description of spatial movements of animals in a predator-prey system within a closed habitat, reproducing some typical patterns of the pursuit-evasion behavior observed in natural populations. In all three models, at each spatial position the animal movements are determined by local conditions only, so the pattern of collective behavior emerges due to self-organization. The movement velocities of animals are proportional to the density gradients of specific cues emitted by individuals of the antagonistic species (pheromones, exometabolites or mechanical waves of the media, e.g., sound). These cues play a role of taxis stimuli: prey attract predators, while predators repel prey. Depending on the nature and the properties of the movement stimulus we propose using either a simplified individual-based model, a continuous taxis pursuit-evasion system, or a little more detailed 'hybrid' approach that combines simulation of the individual movements with the continuous model describing diffusion and decay of the stimuli in an explicit way. These can be used to improve movement models for many species, including large marine predators.

  15. Photoactivated Spatiotemporally-Responsive Nanosensors of in Vivo Protease Activity.

    Science.gov (United States)

    Dudani, Jaideep S; Jain, Piyush K; Kwong, Gabriel A; Stevens, Kelly R; Bhatia, Sangeeta N

    2015-12-22

    Proteases play diverse and important roles in physiology and disease, including influencing critical processes in development, immune responses, and malignancies. Both the abundance and activity of these enzymes are tightly regulated and highly contextual; thus, in order to elucidate their specific impact on disease progression, better tools are needed to precisely monitor in situ protease activity. Current strategies for detecting protease activity are focused on functionalizing synthetic peptide substrates with reporters that emit detection signals following peptide cleavage. However, these activity-based probes lack the capacity to be turned on at sites of interest and, therefore, are subject to off-target activation. Here we report a strategy that uses light to precisely control both the location and time of activity-based sensing. We develop photocaged activity-based sensors by conjugating photolabile molecules directly onto peptide substrates, thereby blocking protease cleavage by steric hindrance. At sites of disease, exposure to ultraviolet light unveils the nanosensors to allow proteases to cleave and release a reporter fragment that can be detected remotely. We apply this spatiotemporally controlled system to probe secreted protease activity in vitro and tumor protease activity in vivo. In vitro, we demonstrate the ability to dynamically and spatially measure metalloproteinase activity in a 3D model of colorectal cancer. In vivo, veiled nanosensors are selectively activated at the primary tumor site in colorectal cancer xenografts to capture the tumor microenvironment-enriched protease activity. The ability to remotely control activity-based sensors may offer a valuable complement to existing tools for measuring biological activity.

  16. Spatiotemporal Variations and Driving Factors of Air Pollution in China

    Directory of Open Access Journals (Sweden)

    Dongsheng Zhan

    2017-12-01

    Full Text Available In recent years, severe and persistent air pollution episodes in China have drawn wide public concern. Based on ground monitoring air quality data collected in 2015 in Chinese cities above the prefectural level, this study identifies the spatiotemporal variations of air pollution and its associated driving factors in China using descriptive statistics and geographical detector methods. The results show that the average air pollution ratio and continuous air pollution ratio across Chinese cities in 2015 were 23.1 ± 16.9% and 16.2 ± 14.8%. The highest levels of air pollution ratio and continuous air pollution ratio were observed in northern China, especially in the Bohai Rim region and Xinjiang province, and the lowest levels were found in southern China. The average and maximum levels of continuous air pollution show distinct spatial variations when compared with those of the continuous air pollution ratio. Monthly changes in both air pollution ratio and continuous air pollution ratio have a U-shaped variation, indicating that the highest levels of air pollution occurred in winter and the lowest levels happened in summer. The results of the geographical detector model further reveal that the effect intensity of natural factors on the spatial disparity of the air pollution ratio is greater than that of human-related factors. Specifically, among natural factors, the annual average temperature, land relief, and relative humidity have the greatest and most significant negative effects on the air pollution ratio, whereas human factors such as population density, the number of vehicles, and Gross Domestic Product (GDP witness the strongest and most significant positive effects on air pollution ratio.

  17. Projects Work!

    Science.gov (United States)

    Textor, Martin R.

    2005-01-01

    The great educational value of projects is emphasized by contrasting negative aspects of the life of today's children with the goals of project work. This is illustrated by a project "Shopping." It is shown what children are learning in such projects and what the advantages of project work are. Relevant topic areas, criteria for selecting a…

  18. Sedentary work

    DEFF Research Database (Denmark)

    Eriksen, Dorte; Rosthøj, Susanne; Burr, Hermann

    2015-01-01

    OBJECTIVE: The aim of this study is to investigate the association between five-year changes in occupational sitting and body mass index (BMI) in working adults. METHODS: We analyzed data from The Danish Work Environment Cohort Study (2005 and 2010, n=3.482). Data on occupational sitting, weight...

  19. Case work

    DEFF Research Database (Denmark)

    Shaw, Ian Frank

    2016-01-01

    Answers to the question just what is the ?case? partly defined the fields of sociology and social work in early 20th century Chicago. Drawing on the archives of the University of Chicago, I describe and appraise the way the ?case? figured in social work at Chicago and elsewhere. I ask...

  20. Regional scale spatio-temporal variability of soil moisture and its relationship with meteorological factors over the Korean peninsula

    Science.gov (United States)

    Cho, Eunsang; Choi, Minha

    2014-08-01

    An understanding soil moisture spatio-temporal variability is essential for hydrological and meteorological research. This work aims at evaluating the spatio-temporal variability of near surface soil moisture and assessing dominant meteorological factors that influence spatial variability over the Korean peninsula from May 1 to September 29, 2011. The results of Kolmogorov-Smirnov tests for goodness of fit showed that all applied distributions (normal, log-normal and generalized extreme value: GEV) were appropriate for the datasets and the GEV distribution described best spatial soil moisture patterns. The relationship between the standard deviation and coefficient of variation (CV) of soil moisture with mean soil moisture contents showed an upper convex shape and an exponentially negative pattern, respectively. Skewness exhibited a decreasing pattern with increasing mean soil moisture contents and kurtosis exhibited the U-shaped relationship. In this regional scale (99,720 km2), we found that precipitation indicated temporally stable features through an ANOVA test considering the meteorological (i.e. precipitation, insolation, air temperature, ground temperature and wind speed) and physical (i.e. soil texture, elevation, topography, and land use) factors. Spatial variability of soil moisture affected by the meteorological forcing is shown as result of the relationship between the meteorological factors (precipitation, insolation, air temperature and ground temperature) and the standard deviation of relative difference of soil moisture contents (SDRDt) which implied the spatial variability of soil moisture. The SDRDt showed a positive relationship with the daily mean precipitation, while a negative relationship with insolation, air temperature and ground temperature. The variation of spatial soil moisture pattern is more sensitive to change in ground temperature rather than air temperature changes. Therefore, spatial variability of soil moisture is greatly affected

  1. Spatiotemporal analysis of aquifers salinization in coastal area of Yunlin, Taiwan

    Science.gov (United States)

    Chen, P.-C.; Tan, Y.-C.

    2012-04-01

    In the past, time and space characteristics often discussed separately. This study adopts regionalized variables theory, and describes the water quality in terms of its structure in time and space to assess the situation of Yunlin. This study applied the Quantum Bayesian Maximum Entropy Toolbox (QtBME), which is a spatiotemporal statistics function, can be applied to estimate and map a non-stationary and non-homogeneous spatiotemporal process under the platform of Quantum GIS (QGIS) software. Kernel smoothing method is used to divide the original process into a deterministic trend and a stationary and homogeneous spatiotemporal process, assuming that a spatiotemporal process can be divided into high and low frequency. The covariance model of the process of high frequency is selected objectively by particle swarm optimization (PSO) method and Akaike's information criterion (AIC). Bayesian maximum entropy method is then applied to spatiotemporal mapping of the variable of interest. In this study, QtBME estimated the situation of aquifers salinization at Yunlin coastal area in 1992 to 2010. Finally, one investigated the rainfall and aquifers salinization on the degree of impact.

  2. COMPARISON OF SPATIOTEMPORAL MAPPING TECHNIQUES FOR ENORMOUS ETL AND EXPLOITATION PATTERNS

    Directory of Open Access Journals (Sweden)

    R. Deiotte

    2017-10-01

    Full Text Available The need to extract, transform, and exploit enormous volumes of spatiotemporal data has exploded with the rise of social media, advanced military sensors, wearables, automotive tracking, etc. However, current methods of spatiotemporal encoding and exploitation simultaneously limit the use of that information and increase computing complexity. Current spatiotemporal encoding methods from Niemeyer and Usher rely on a Z-order space filling curve, a relative of Peano’s 1890 space filling curve, for spatial hashing and interleaving temporal hashes to generate a spatiotemporal encoding. However, there exist other space-filling curves, and that provide different manifold coverings that could promote better hashing techniques for spatial data and have the potential to map spatiotemporal data without interleaving. The concatenation of Niemeyer’s and Usher’s techniques provide a highly efficient space-time index. However, other methods have advantages and disadvantages regarding computational cost, efficiency, and utility. This paper explores the several methods using a range of sizes of data sets from 1K to 10M observations and provides a comparison of the methods.

  3. A Spatio-Temporally Explicit Random Encounter Model for Large-Scale Population Surveys.

    Directory of Open Access Journals (Sweden)

    Jussi Jousimo

    Full Text Available Random encounter models can be used to estimate population abundance from indirect data collected by non-invasive sampling methods, such as track counts or camera-trap data. The classical Formozov-Malyshev-Pereleshin (FMP estimator converts track counts into an estimate of mean population density, assuming that data on the daily movement distances of the animals are available. We utilize generalized linear models with spatio-temporal error structures to extend the FMP estimator into a flexible Bayesian modelling approach that estimates not only total population size, but also spatio-temporal variation in population density. We also introduce a weighting scheme to estimate density on habitats that are not covered by survey transects, assuming that movement data on a subset of individuals is available. We test the performance of spatio-temporal and temporal approaches by a simulation study mimicking the Finnish winter track count survey. The results illustrate how the spatio-temporal modelling approach is able to borrow information from observations made on neighboring locations and times when estimating population density, and that spatio-temporal and temporal smoothing models can provide improved estimates of total population size compared to the FMP method.

  4. Research of Cadastral Data Modelling and Database Updating Based on Spatio-temporal Process

    Directory of Open Access Journals (Sweden)

    ZHANG Feng

    2016-02-01

    Full Text Available The core of modern cadastre management is to renew the cadastre database and keep its currentness,topology consistency and integrity.This paper analyzed the changes and their linkage of various cadastral objects in the update process.Combined object-oriented modeling technique with spatio-temporal objects' evolution express,the paper proposed a cadastral data updating model based on the spatio-temporal process according to people's thought.Change rules based on the spatio-temporal topological relations of evolution cadastral spatio-temporal objects are drafted and further more cascade updating and history back trace of cadastral features,land use and buildings are realized.This model implemented in cadastral management system-ReGIS.Achieved cascade changes are triggered by the direct driving force or perceived external events.The system records spatio-temporal objects' evolution process to facilitate the reconstruction of history,change tracking,analysis and forecasting future changes.

  5. Comparison of Spatiotemporal Mapping Techniques for Enormous Etl and Exploitation Patterns

    Science.gov (United States)

    Deiotte, R.; La Valley, R.

    2017-10-01

    The need to extract, transform, and exploit enormous volumes of spatiotemporal data has exploded with the rise of social media, advanced military sensors, wearables, automotive tracking, etc. However, current methods of spatiotemporal encoding and exploitation simultaneously limit the use of that information and increase computing complexity. Current spatiotemporal encoding methods from Niemeyer and Usher rely on a Z-order space filling curve, a relative of Peano's 1890 space filling curve, for spatial hashing and interleaving temporal hashes to generate a spatiotemporal encoding. However, there exist other space-filling curves, and that provide different manifold coverings that could promote better hashing techniques for spatial data and have the potential to map spatiotemporal data without interleaving. The concatenation of Niemeyer's and Usher's techniques provide a highly efficient space-time index. However, other methods have advantages and disadvantages regarding computational cost, efficiency, and utility. This paper explores the several methods using a range of sizes of data sets from 1K to 10M observations and provides a comparison of the methods.

  6. VISUALIZATION OF SPATIO-TEMPORAL RELATIONS IN MOVEMENT EVENT USING MULTI-VIEW

    Directory of Open Access Journals (Sweden)

    K. Zheng

    2017-09-01

    Full Text Available Spatio-temporal relations among movement events extracted from temporally varying trajectory data can provide useful information about the evolution of individual or collective movers, as well as their interactions with their spatial and temporal contexts. However, the pure statistical tools commonly used by analysts pose many difficulties, due to the large number of attributes embedded in multi-scale and multi-semantic trajectory data. The need for models that operate at multiple scales to search for relations at different locations within time and space, as well as intuitively interpret what these relations mean, also presents challenges. Since analysts do not know where or when these relevant spatio-temporal relations might emerge, these models must compute statistical summaries of multiple attributes at different granularities. In this paper, we propose a multi-view approach to visualize the spatio-temporal relations among movement events. We describe a method for visualizing movement events and spatio-temporal relations that uses multiple displays. A visual interface is presented, and the user can interactively select or filter spatial and temporal extents to guide the knowledge discovery process. We also demonstrate how this approach can help analysts to derive and explain the spatio-temporal relations of movement events from taxi trajectory data.

  7. AN ADAPTIVE ORGANIZATION METHOD OF GEOVIDEO DATA FOR SPATIO-TEMPORAL ASSOCIATION ANALYSIS

    Directory of Open Access Journals (Sweden)

    C. Wu

    2015-07-01

    Full Text Available Public security incidents have been increasingly challenging to address with their new features, including large-scale mobility, multi-stage dynamic evolution, spatio-temporal concurrency and uncertainty in the complex urban environment, which require spatio-temporal association analysis among multiple regional video data for global cognition. However, the existing video data organizational methods that view video as a property of the spatial object or position in space dissever the spatio-temporal relationship of scattered video shots captured from multiple video channels, limit the query functions on interactive retrieval between a camera and its video clips and hinder the comprehensive management of event-related scattered video shots. GeoVideo, which maps video frames onto a geographic space, is a new approach to represent the geographic world, promote security monitoring in a spatial perspective and provide a highly feasible solution to this problem. This paper analyzes the large-scale personnel mobility in public safety events and proposes a multi-level, event-related organization method with massive GeoVideo data by spatio-temporal trajectory. This paper designs a unified object identify(ID structure to implicitly store the spatio-temporal relationship of scattered video clips and support the distributed storage management of massive cases. Finally, the validity and feasibility of this method are demonstrated through suspect tracking experiments.

  8. Facile fabrication of a near-infrared responsive nanocarrier for spatiotemporally controlled chemo-photothermal synergistic cancer therapy

    Science.gov (United States)

    Wan, Hao; Zhang, Yi; Liu, Zheyi; Xu, Guiju; Huang, Guang; Ji, Yongsheng; Xiong, Zhichao; Zhang, Quanqing; Dong, Jing; Zhang, Weibing; Zou, Hanfa

    2014-07-01

    Remote-controlled nanocarriers for drug delivery are of great promise to provide timely, sensitive and spatiotemporally selective treatments for cancer therapy. Due to convenient and precise manipulation, deep penetration through tissues and excellent biocompatibility, near-infrared (NIR) irradiation is a preferred external stimulus for triggering the release of loaded drugs. In this work, for spatiotemporally controlled chemo-photothermal synergistic cancer therapy, a NIR responsive nanocarrier was fabricated using reduced graphene oxide nanosheets (rNGO) decorated with mesoporous silica shell and the subsequent functionalization of the thermoresponsive polymer brushes (pNIPAM-co-pAAm) at the outlet of the silica pore channels. rNGO, which combined with the mesoporous silica shell provide a high loading capacity for anticancer drugs (doxorubicin, DOX), was assigned to sense NIR irradiation for the manipulation of pNIPAM-co-pAAm valve to control the diffusion of loaded DOX. Under NIR irradiation, rNGO would generate heat, which could not only elevate the surrounding temperature over the low critical solution temperature (LCST) of pNIPAM-co-pAAm to open the thermoresponsive polymer valve and promote the diffusion of DOX, but also kill the cancer cells through the hypothermia effect. By manipulating NIR irradiation, the nanocarrier exhibited efficiently controlled release of loaded DOX both in the buffer and in living HeLa cells (the model cancer cells), providing powerful and site-targeted treatments, which can be attributed to synergistic effects of chemo-photothermal therapy. To sum up, this novel nanocarrier is an excellent drug delivery platform in remote-controlled chemo-photothermal synergistic cancer therapy via NIR irradiation.Remote-controlled nanocarriers for drug delivery are of great promise to provide timely, sensitive and spatiotemporally selective treatments for cancer therapy. Due to convenient and precise manipulation, deep penetration through

  9. Work Stress

    OpenAIRE

    Roeters, Anne

    2014-01-01

    Most of us agree that stress is a growing problem within organizations. We hear about the postal workers who had killed fellow employees and supervisors, and then hear that a major cause of tension is at work. Friends tell us that they are stressed due to increased workload and he has to work overtime because the company is restructured. We read the polls that employees complain about the stress in trying to balance family life with the work. Stress is a dynamic condition in which an individu...

  10. Does "Social Work Abstracts" Work?

    Science.gov (United States)

    Holden, Gary; Barker, Kathleen; Covert-Vail, Lucinda; Rosenberg, Gary; Cohen, Stephanie A.

    2008-01-01

    Objective: The current study seeks to provide estimates of the adequacy of journal coverage in the Social Work Abstracts (SWA) database. Method: A total of 23 journals listed in the Journal Citation Reports social work category during the 1997 to 2005 period were selected for study. Issue-level coverage estimates were obtained for SWA and…

  11. Music and metronome cues produce different effects on gait spatiotemporal measures but not gait variability in healthy older adults.

    Science.gov (United States)

    Wittwer, Joanne E; Webster, Kate E; Hill, Keith

    2013-02-01

    Rhythmic auditory cues including music and metronome beats have been used, sometimes interchangeably, to improve disordered gait arising from a range of clinical conditions. There has been limited investigation into whether there are optimal cue types. Different cue types have produced inconsistent effects across groups which differed in both age and clinical condition. The possible effect of normal ageing on response to different cue types has not been reported for gait. The aim of this study was to determine the effects of both rhythmic music and metronome cues on gait spatiotemporal measures (including variability) in healthy older people. Twelve women and seven men (>65 years) walked on an instrumented walkway at comfortable pace and then in time to each of rhythmic music and metronome cues at comfortable pace stepping frequency. Music but not metronome cues produced a significant increase in group mean gait velocity of 4.6 cm/s, due mostly to a significant increase in group mean stride length of 3.1cm. Both cue types produced a significant but small increase in cadence of 1 step/min. Mean spatio-temporal variability was low at baseline and did not increase with either cue type suggesting cues did not disrupt gait timing. Study findings suggest music and metronome cues may not be used interchangeably and cue type as well as frequency should be considered when evaluating effects of rhythmic auditory cueing on gait. Further work is required to determine whether optimal cue types and frequencies to improve walking in different clinical groups can be identified. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Detection and Evaluation of Spatio-Temporal Spike Patterns in Massively Parallel Spike Train Data with SPADE

    Directory of Open Access Journals (Sweden)

    Pietro Quaglio

    2017-05-01

    Full Text Available Repeated, precise sequences of spikes are largely considered a signature of activation of cell assemblies. These repeated sequences are commonly known under the name of spatio-temporal patterns (STPs. STPs are hypothesized to play a role in the communication of information in the computational process operated by the cerebral cortex. A variety of statistical methods for the detection of STPs have been developed and applied to electrophysiological recordings, but such methods scale poorly with the current size of available parallel spike train recordings (more than 100 neurons. In this work, we introduce a novel method capable of overcoming the computational and statistical limits of existing analysis techniques in detecting repeating STPs within massively parallel spike trains (MPST. We employ advanced data mining techniques to efficiently extract repeating sequences of spikes from the data. Then, we introduce and compare two alternative approaches to distinguish statistically significant patterns from chance sequences. The first approach uses a measure known as conceptual stability, of which we investigate a computationally cheap approximation for applications to such large data sets. The second approach is based on the evaluation of pattern statistical significance. In particular, we provide an extension to STPs of a method we recently introduced for the evaluation of statistical significance of synchronous spike patterns. The performance of the two approaches is evaluated in terms of computational load and statistical power on a variety of artificial data sets that replicate specific features of experimental data. Both methods provide an effective and robust procedure for detection of STPs in MPST data. The method based on significance evaluation shows the best overall performance, although at a higher computational cost. We name the novel procedure the spatio-temporal Spike PAttern Detection and Evaluation (SPADE analysis.

  13. The spatiotemporal dynamics of microbes in the near-surface atmosphere

    Science.gov (United States)

    Bowers, Robert Michael

    With this dissertation, I present four culture independent studies examining the spatiotemporal distributions of microbial communities in the near-surface atmosphere. The goals of this dissertation work were to examine the biogeographical patterns that airborne microbes exhibit over a variety of spatiotemporal scales, and to determine the likely sources of bacteria to the near-surface environment. First I explored the short-term (two-week) changes in microbial community structure (bacteria, fungi and pollen) of the near surface atmosphere at the high elevation research site, Storm Peak Laboratory, located in northern Colorado, USA. This study revealed that the nearsurface atmosphere is abundant with microbes, and that the airborne communities are composed of taxa that are typical of cold environments. Additionally, the bacteria identified in the air samples showed high sequence similarity to bacterial lineages possessing the ice nucleating phenotype, suggesting the possibility of bacterial induced cloud formation. Second, I examined the spatial diversity of airborne bacterial communities across the three dominant land-use types of the Colorado Front Range: forests, suburban areas, and agricultural sites. The airborne communities exhibited significant community level shifts across the three land-use types, however the differences could not be attributed to the prevailing meteorological conditions, suggesting that the characteristics of the local terrestrial surfaces have a greater influence on the airborne communities than the prevailing meteorology. Overall, the airborne communities above the three land-use types appeared to be unique to potential source environments, however the taxa driving the land-use patterns were related to those taxa that were indicative of either soils or leaf surfaces. Third, I carried out a seasonal (summer and winter) study of the airborne bacterial communities of the Great Lakes region of the USA. The bacterial communities inhabiting

  14. Group Work.

    Science.gov (United States)

    Wilson, Kristy J; Brickman, Peggy; Brame, Cynthia J

    2018-01-01

    Science, technology, engineering, and mathematics faculty are increasingly incorporating both formal and informal group work in their courses. Implementing group work can be improved by an understanding of the extensive body of educational research studies on this topic. This essay describes an online, evidence-based teaching guide published by CBE-Life Sciences Education ( LSE ). The guide provides a tour of research studies and resources related to group work (including many articles from LSE ). Instructors who are new to group work, as well as instructors who have experienced difficulties in implementing group work, may value the condensed summaries of key research findings. These summaries are organized by teaching challenges, and actionable advice is provided in a checklist for instructors. Education researchers may value the inclusion of empirical studies, key reviews, and meta-analyses of group-work studies. In addition to describing key features of the guide, this essay also identifies areas in which further empirical studies are warranted. © 2018 K. J. Wilson et al. CBE—Life Sciences Education © 2018 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  15. A novel method for one-way hash function construction based on spatiotemporal chaos

    Energy Technology Data Exchange (ETDEWEB)

    Ren Haijun [College of Software Engineering, Chongqing University, Chongqing 400044 (China); State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing University, Chongqing 400044 (China)], E-mail: jhren@cqu.edu.cn; Wang Yong; Xie Qing [Key Laboratory of Electronic Commerce and Logistics of Chongqing, Chongqing University of Posts and Telecommunications, Chongqing 400065 (China); Yang Huaqian [Department of Computer and Modern Education Technology, Chongqing Education of College, Chongqing 400067 (China)

    2009-11-30

    A novel hash algorithm based on a spatiotemporal chaos is proposed. The original message is first padded with zeros if needed. Then it is divided into a number of blocks each contains 32 bytes. In the hashing process, each block is partitioned into eight 32-bit values and input into the spatiotemporal chaotic system. Then, after iterating the system for four times, the next block is processed by the same way. To enhance the confusion and diffusion effect, the cipher block chaining (CBC) mode is adopted in the algorithm. The hash value is obtained from the final state value of the spatiotemporal chaotic system. Theoretic analyses and numerical simulations both show that the proposed hash algorithm possesses good statistical properties, strong collision resistance and high efficiency, as required by practical keyed hash functions.

  16. Single-shot spatiotemporal measurements of ultrashort THz waveforms using temporal electric-field cross correlation

    Energy Technology Data Exchange (ETDEWEB)

    Matlis, Nicholas; Plateau, Guillaume; van Tilborg, Jeroen; Leemans, Wim

    2011-06-17

    A new single-shot technique based on linear spectral interferometry between a temporally short reader pulse and a temporally long probe pulse is demonstrated for measuring the spatiotemporal phase and amplitude of an optical probe for use as an ultrafast diagnostic. The probe spatiotemporal field information is recovered, with a resolution set by the duration of the reader pulse, by applying a single Fourier transform operation to the interferogram image, without need of any reference data. The technique was used in conjunction with electro-optic sampling to measure waveforms of coherent, ultrashort THz pulses emitted by electron bunches from a laser-plasma accelerator with sub-50fs resolution. The presence of strong spatiotemporal coupling in the THz waveforms and of complex temporal electron-bunch structure was determined.

  17. Adjusted functional boxplots for spatio-temporal data visualization and outlier detection

    KAUST Repository

    Sun, Ying

    2011-10-24

    This article proposes a simulation-based method to adjust functional boxplots for correlations when visualizing functional and spatio-temporal data, as well as detecting outliers. We start by investigating the relationship between the spatio-temporal dependence and the 1.5 times the 50% central region empirical outlier detection rule. Then, we propose to simulate observations without outliers on the basis of a robust estimator of the covariance function of the data. We select the constant factor in the functional boxplot to control the probability of correctly detecting no outliers. Finally, we apply the selected factor to the functional boxplot of the original data. As applications, the factor selection procedure and the adjusted functional boxplots are demonstrated on sea surface temperatures, spatio-temporal precipitation and general circulation model (GCM) data. The outlier detection performance is also compared before and after the factor adjustment. © 2011 John Wiley & Sons, Ltd.

  18. Plant diversity increases spatio-temporal niche complementarity in plant-pollinator interactions.

    Science.gov (United States)

    Venjakob, Christine; Klein, Alexandra-Maria; Ebeling, Anne; Tscharntke, Teja; Scherber, Christoph

    2016-04-01

    Ongoing biodiversity decline impairs ecosystem processes, including pollination. Flower visitation, an important indicator of pollination services, is influenced by plant species richness. However, the spatio-temporal responses of different pollinator groups to plant species richness have not yet been analyzed experimentally. Here, we used an experimental plant species richness gradient to analyze plant-pollinator interactions with an unprecedented spatio-temporal resolution. We observed four pollinator functional groups (honeybees, bumblebees, solitary bees, and hoverflies) in experimental plots at three different vegetation strata between sunrise and sunset. Visits were modified by plant species richness interacting with time and space. Furthermore, the complementarity of pollinator functional groups in space and time was stronger in species-rich mixtures. We conclude that high plant diversity should ensure stable pollination services, mediated via spatio-temporal niche complementarity in flower visitation.

  19. spate: An R Package for Spatio-Temporal Modeling with a Stochastic Advection-Diffusion Process

    Directory of Open Access Journals (Sweden)

    Fabio Sigrist

    2015-02-01

    This package aims at providing tools for simulating and modeling of spatio-temporal processes using an SPDE based approach. The package contains functions for obtaining parametrizations, such as propagator or innovation covariance matrices, of the spatio-temporal model. This allows for building customized hierarchical Bayesian models using the SPDE based model at the process stage. The functions of the package then provide computationally efficient algorithms needed for doing inference with the hierarchical model. Furthermore, an adaptive Markov chain Monte Carlo (MCMC algorithm implemented in the package can be used as an algorithm for doing inference without any additional modeling. This function is flexible and allows for application specific customizing. The MCMC algorithm supports data that follow a Gaussian or a censored distribution with point mass at zero. Spatio-temporal covariates can be included in the model through a regression term.

  20. Research on target tracking algorithm based on spatio-temporal context

    Science.gov (United States)

    Li, Baiping; Xu, Sanmei; Kang, Hongjuan

    2017-07-01

    In this paper, a novel target tracking algorithm based on spatio-temporal context is proposed. During the tracking process, the camera shaking or occlusion may lead to the failure of tracking. The proposed algorithm can solve this problem effectively. The method use the spatio-temporal context algorithm as the main research object. We get the first frame's target region via mouse. Then the spatio-temporal context algorithm is used to get the tracking targets of the sequence of frames. During this process a similarity measure function based on perceptual hash algorithm is used to judge the tracking results. If tracking failed, reset the initial value of Mean Shift algorithm for the subsequent target tracking. Experiment results show that the proposed algorithm can achieve real-time and stable tracking when camera shaking or target occlusion.

  1. Evaluation of high resolution spatio-temporal precipitation extremes from a stochastic weather generator

    DEFF Research Database (Denmark)

    Sørup, Hjalte Jomo Danielsen; Christensen, O. B.; Arnbjerg-Nielsen, Karsten

    2017-01-01

    gauges in the model area. The spatiotemporal performance of the model with respect to precipitation extremes is evaluated in the points of a 2x2 km regular grid covering the full model area. The model satisfactorily reproduces the extreme behaviour of the observed precipitation with respect to event...... intensity levels and unconditional spatial correlation when evaluated using an event based ranking approach at point scale and an advanced spatiotemporal coupling of extreme events. Prospectively the model can be used as a tool to evaluate the impact of climate change without relying on precipitation output......Spatio-temporal rainfall is modelled for the North-Eastern part of Zealand (Denmark) using the Spatio-Temporal Neyman-Scott Rectangular Pulses model as implemented in the RainSim software. Hourly precipitation series for fitting the model are obtained from a dense network of tipping bucket rain...

  2. Evaluation of high resolution spatio-temporal precipitation extremes from a stochastic weather generator

    DEFF Research Database (Denmark)

    Sørup, Hjalte Jomo Danielsen; Christensen, O. B.; Arnbjerg-Nielsen, Karsten

    gauges in the model area. The spatio-temporal performance of the model with respect to precipitation extremes is evaluated in the points of a 2x2 km regular grid covering the full model area. The model satisfactorily reproduces the extreme behaviour of the observed precipitation with respect to event...... intensity levels and unconditional spatial correlation when evaluated using an event based ranking approach at point scale and an advanced spatio-temporal coupling of extreme events. Prospectively the model can be used as a tool to evaluate the impact of climate change without relying onprecipitation output......Spatio-temporal rainfall is modelled for the North-Eastern part of Zealand (Denmark) using the Spatio-Temporal Neyman-Scott Rectangular Pulses model as implemented in the RainSim software. Hourly precipitation series for fitting the model are obtained from a dense network of tipping bucket rain...

  3. A Comparative Study of Frequent and Maximal Periodic Pattern Mining Algorithms in Spatiotemporal Databases

    Science.gov (United States)

    Obulesu, O.; Rama Mohan Reddy, A., Dr; Mahendra, M.

    2017-08-01

    Detecting regular and efficient cyclic models is the demanding activity for data analysts due to unstructured, vigorous and enormous raw information produced from web. Many existing approaches generate large candidate patterns in the occurrence of huge and complex databases. In this work, two novel algorithms are proposed and a comparative examination is performed by considering scalability and performance parameters. The first algorithm is, EFPMA (Extended Regular Model Detection Algorithm) used to find frequent sequential patterns from the spatiotemporal dataset and the second one is, ETMA (Enhanced Tree-based Mining Algorithm) for detecting effective cyclic models with symbolic database representation. EFPMA is an algorithm grows models from both ends (prefixes and suffixes) of detected patterns, which results in faster pattern growth because of less levels of database projection compared to existing approaches such as Prefixspan and SPADE. ETMA uses distinct notions to store and manage transactions data horizontally such as segment, sequence and individual symbols. ETMA exploits a partition-and-conquer method to find maximal patterns by using symbolic notations. Using this algorithm, we can mine cyclic models in full-series sequential patterns including subsection series also. ETMA reduces the memory consumption and makes use of the efficient symbolic operation. Furthermore, ETMA only records time-series instances dynamically, in terms of character, series and section approaches respectively. The extent of the pattern and proving efficiency of the reducing and retrieval techniques from synthetic and actual datasets is a really open & challenging mining problem. These techniques are useful in data streams, traffic risk analysis, medical diagnosis, DNA sequence Mining, Earthquake prediction applications. Extensive investigational outcomes illustrates that the algorithms outperforms well towards efficiency and scalability than ECLAT, STNR and MAFIA approaches.

  4. WRF added value to capture the spatio-temporal drought variability

    Science.gov (United States)

    García-Valdecasas Ojeda, Matilde; Quishpe-Vásquez, César; Raquel Gámiz-Fortis, Sonia; Castro-Díez, Yolanda; Jesús Esteban-Parra, María

    2017-04-01

    Regional Climate Models (RCM) has been widely used as a tool to perform high resolution climate fields in areas with high climate variability such as Spain. However, the outputs provided by downscaling techniques have many sources of uncertainty associated at different aspects. In this study, the ability of the Weather Research and Forecasting (WRF) model to capture drought conditions has been analyzed. The WRF simulation was carried out for a period that spanned from 1980 to 2010 over a domain centered in the Iberian Peninsula with a spatial resolution of 0.088°, and nested in the coarser EURO-CORDEX domain (0.44° spatial resolution). To investigate the spatiotemporal drought variability, the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) has been computed at two different timescales: 3- and 12-months due to its suitability to study agricultural and hydrological droughts. The drought indices computed from WRF outputs were compared with those obtained from the observational (MOTEDAS and MOPREDAS) datasets. In order to assess the added value provided by downscaled fields, these indices were also computed from the ERA-Interim Re-Analysis database, which provides the lateral and boundary conditions of the WRF simulations. Results from this study indicate that WRF provides a noticeable benefit with respect to ERA-Interim for many regions in Spain in terms of drought indices, greater for SPI than for SPEI. The improvement offered by WRF depends on the region, index and timescale analyzed, being greater at longer timescales. These findings prove the reliability of the downscaled fields to detect drought events and, therefore, it is a remarkable source of knowledge for a suitable decision making related to water-resource management. Keywords: Drought, added value, Regional Climate Models, WRF, SPEI, SPI. Acknowledgements: This work has been financed by the projects P11-RNM-7941 (Junta de Andalucía-Spain) and

  5. Spatio-temporal aspects of the domain propagation in a spin-crossover lattice with defect

    Science.gov (United States)

    Traiche, R.; Oubouchou, H.; Zergoug, M.; Boukheddaden, K.

    2017-07-01

    the collective spatiotemporal dynamics of the metastable high-spin state (HS) upon relaxation towards the low-spin (LS) is investigated using an electro-elastic model which includes the change of the spin states and the lattice volume at the transition. The present work focusses on the case of a lattice in which is embedded a structural defect in the center, represented here by a hole with a fixed size. The simulations are made on a 2D rectangular-shaped and compared to those of an ideal system. To account for the volume change, we set the distances between the sites as spin-dependent which requires the use of Monte Carlo simulations on spin states and atomic positions to solve the present problem. It is found that the presence of the defect affects the dynamics of the spin-crossover transformations which starts stochastically from a corner of the lattice, then propagates in the first stage along the width (shortest distance to the surface), before to proceed via a second longitudinal regime whose velocity slows down significantly at the vicinity of the defect, which plays the role of a pining center. After a while, the interface leaves the defect, and accelerates when it approaches the lattice's border. We have also investigated the spatial dependence of the displacement field, from which we derived the distribution of the divergence and rotational of the displacement field, which directly connects to the trace of the strain tensor and to shear strains respectively. Valuable information on the relaxation process of the elastic field are derived and discussed in direct relation with the presence of the defect.

  6. Spatiotemporal blue noise coded aperture design for multi-shot compressive spectral imaging.

    Science.gov (United States)

    Correa, Claudia V; Arguello, Henry; Arce, Gonzalo R

    2016-12-01

    Multi-shot coded aperture snapshot spectral imaging (CASSI) systems capture the spectral information of a scene using a small set of coded focal plane array (FPA) compressive measurements. Compressed sensing (CS) reconstruction algorithms are then used to reconstruct the underlying spectral 3D data cube from an underdetermined system of linear equations. Multiple snapshots result in a less ill-posed inverse problem and improved reconstructions. The only varying components in CASSI are the coded apertures, whose structure is crucial inasmuch as they determine the minimum number of FPA measurements needed for correct image reconstruction and the corresponding attainable quality. Traditionally, the spatial structures of the coded aperture entries are selected at random, leading to suboptimal reconstruction solutions. This work presents an optimal structure design of a set of coded apertures by optimizing the concentration of measure of the multi-shot CASSI sensing matrix and its incoherence with respect to the sparse representation basis. First, the CASSI matrix system representation in terms of the ensemble of random projections is established. Then, the restricted isometry property (RIP) of the CASSI projections is determined as a function of the coded aperture entries. The optimal coded aperture structures are designed under the criterion of satisfying the RIP with high probability, coined spatiotemporal blue noise (BN) coded apertures. Furthermore, an algorithm that implements the BN ensembles is presented. Extensive simulations and a testbed implementation are developed to illustrate the improvements of the BN coded apertures over the traditionally used coded aperture structures, in terms of spectral image reconstruction PSNR and SSIM.

  7. Spatio-Temporal Data Analysis at Scale Using Models Based on Gaussian Processes

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Michael [Univ. of Chicago, IL (United States)

    2017-03-13

    Gaussian processes are the most commonly used statistical model for spatial and spatio-temporal processes that vary continuously. They are broadly applicable in the physical sciences and engineering and are also frequently used to approximate the output of complex computer models, deterministic or stochastic. We undertook research related to theory, computation, and applications of Gaussian processes as well as some work on estimating extremes of distributions for which a Gaussian process assumption might be inappropriate. Our theoretical contributions include the development of new classes of spatial-temporal covariance functions with desirable properties and new results showing that certain covariance models lead to predictions with undesirable properties. To understand how Gaussian process models behave when applied to deterministic computer models, we derived what we believe to be the first significant results on the large sample properties of estimators of parameters of Gaussian processes when the actual process is a simple deterministic function. Finally, we investigated some theoretical issues related to maxima of observations with varying upper bounds and found that, depending on the circumstances, standard large sample results for maxima may or may not hold. Our computational innovations include methods for analyzing large spatial datasets when observations fall on a partially observed grid and methods for estimating parameters of a Gaussian process model from observations taken by a polar-orbiting satellite. In our application of Gaussian process models to deterministic computer experiments, we carried out some matrix computations that would have been infeasible using even extended precision arithmetic by focusing on special cases in which all elements of the matrices under study are rational and using exact arithmetic. The applications we studied include total column ozone as measured from a polar-orbiting satellite, sea surface temperatures over the

  8. Spatio-temporal modeling of connectome-scale brain network interactions via time-evolving graphs.

    Science.gov (United States)

    Yuan, Jing; Li, Xiang; Zhang, Jinhe; Luo, Liao; Dong, Qinglin; Lv, Jinglei; Zhao, Yu; Jiang, Xi; Zhang, Shu; Zhang, Wei; Liu, Tianming

    2017-11-09

    Many recent literature studies have revealed interesting dynamics patterns of functional brain networks derived from fMRI data. However, it has been rarely explored how functional networks spatially overlap (or interact) and how such connectome-scale network interactions temporally evolve. To explore these unanswered questions, this paper presents a novel framework for spatio-temporal modeling of connectome-scale functional brain network interactions via two main effective computational methodologies. First, to integrate, pool and compare brain networks across individuals and their cognitive states under task performances, we designed a novel group-wise dictionary learning scheme to derive connectome-scale consistent brain network templates that can be used to define the common reference space of brain network interactions. Second, the temporal dynamics of spatial network interactions is modeled by a weighted time-evolving graph, and then a data-driven unsupervised learning algorithm based on the dynamic behavioral mixed-membership model (DBMM) is adopted to identify behavioral patterns of brain networks during the temporal evolution process of spatial overlaps/interactions. Experimental results on the Human Connectome Project (HCP) task fMRI data showed that our methods can reveal meaningful, diverse behavior patterns of connectome-scale network interactions. In particular, those networks' behavior patterns are distinct across HCP tasks such as motor, working memory, language and social tasks, and their dynamics well correspond to the temporal changes of specific task designs. In general, our framework offers a new approach to characterizing human brain function by quantitative description for the temporal evolution of spatial overlaps/interactions of connectome-scale brain networks in a standard reference space. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Soil moisture spatio-temporal behavior of Pinus pinaster stands on sandy flatlands of central Spain.

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Sanz, V.; Garcia-Vinas, J. I.

    2011-07-01

    Pinus pinaster stands in the center of the Iberian Peninsula frequently grow in a unique hydrological system characterized by a variable groundwater table near the soil surface and highly permeable soils (arenosols). Over the last few decades, this superficial aquifer has been overused as a water resource, especially for irrigated crops. Overuse has reached a critical level and has caused various environmental impacts and a water sustainability crisis wherein rainfall variability does not allow for a sufficient level of aquifer recharge by natural means. Within this changing scenario, soil water significantly affects the spatio-temporal ecological response, necessitating more extensive characterization of the complex soil-tree water relationship. The primary goal of the present work was to evaluate the influence of root zone soil moisture on the observed spatial response of Pinus pinaster stands. Volumetric soil moisture content was measured at eleven forest sites, using time-domain reflectometry (TDR), over a two-year observation period. The results demonstrate that the combined effect of groundwater table proximity and dune morphology associated with this area are the main factors driving very different water availability conditions among the monitored hydrological response units, which modulate maritime pine installation and development. Topographically lower areas are more heterogeneous in terms of soil moisture behavior. In these areas, the conifer forests that are connected to the water table may be the most sensitive to land use changes within current environmental change scenarios. Consequently, in these pine ecosystems, the combined influences of geomorphology and water table proximity on variations in root zone soil moisture are essential and must be considered to develop adequate adaptive management models. (Author) 25 refs.

  10. Towards operational hydrology for a thorough spatio-temporal exploration of the Critical Zone

    Science.gov (United States)

    Chatton, Eliot; Labasque, Thierry; Guillou, Aurélie; Aquilina, Luc; Bour, Olivier; Le Borgne, Tanguy; Longuevergne, Laurent

    2017-04-01

    Over the last century, the Critical Zone faced remarkable climate and land use changes increasing the pressures on the Hydrosphere and giving rise to numerous environmental consequences in terms of water quantity and quality. From now on, the Critical Zone must face the challenge to supply 9 billion people with quality food and safe drinking water in a context of global warming. For the Hydrosphere, this challenge could be addressed with a better understanding of the dynamics and resilience of aquatic environments (rivers, lakes, groundwaters, oceans). In view of the spatial and temporal variety and variability of flow dynamics and biogeochemical reactions occurring in the Hydrosphere a new investigation method is needed. This study approaches the concept of "operational hydrology" aiming to enhance either the spatio-temporal distribution and the quality of environmental data for a thorough exploration of the Hydrosphere. To illustrate our approach, we present natural and anthropogenic dissolved gas data (He, Ne, Ar, Kr, Xe, N2, O2, CO2, CH4, N2O, H2, BTEX, and some VOCs) measured in situ with a CF-MIMS (Chatton et al, 2016) installed in a mobile laboratory arranged in an all-terrain truck (CRITEX-Lab). This ongoing work focuses on groundwater and the field investigation of residence time distributions, recharge processes (origins), water flow paths and mixing, biogeochemical reactivity and contamination (sources). The rationale behind "operational hydrology" could be applied to the field measurement at high-frequency of many other environmental parameters (temperature, cations, anions, isotopes, micro-organisms) not only for the investigation of groundwaters but also rivers, lakes and oceans. Eliot Chatton, Thierry Labasque, Jérôme de La Bernardie, Nicolas Guihéneuf, Olivier Bour and Luc Aquilina; Field Continuous Measurement of Dissolved Gases with a CF-MIMS: Applications to the Physics and Biogeochemistry of Groundwater Flow; Environmental Science

  11. Spatiotemporal tracer variability in glacier melt and its influence on hydrograph separation

    Science.gov (United States)

    Schmieder, Jan; Marke, Thomas; Strasser, Ulrich

    2017-04-01

    Glaciers are important seasonal water contributors in many mountainous regions. Knowledge on the timing and amount of glacier melt water is crucial for water resources management, especially in downstream regions where the water is needed (hydropower, drinking water) or where it represents a potential risk (drought, flood). This becomes even more relevant in a changing climate. Environmental tracers are a useful tool in the assessment of ice water resources, because they provide information about the sources, flow paths and traveling times of water contributing to streamflow at the catchment scale. Hydrometric and meteorological measurements combined with tracer analyses help to unravel streamflow composition and improve the understanding of hydroclimatological processes. Empirical studies on runoff composition are necessary to parameterize and validate hydrological models in a process-oriented manner, rather than comparing total measured and simulated runoff only. In the present study three approaches of hydrograph separation are compared to decide which sampling frequency is required to capture the spatiotemporal variability of glacier melt, and to draw implications for future studies of streamflow partitioning. Therefore glacier melt contributions to a proglacial stream at the sub-daily, daily, and seasonal scale were estimated using electrical conductivity and oxygen-18 as tracers. The field work was conducted during December 2015 and September 2016 in the glaciated (34%) high-elevation catchment of the Hochjochbach, a small sub-basin (17 km2) of the Oetztaler Ache river in the Austrian Alps, ranging from 2400 to 3500 m a.s.l. in elevation. Hydroclimatological data was provided by an automatic weather station and a streamflow gauging station equipped with a pressure transducer. Water samples of streamflow, glacier melt, and rain were collected throughout the winter period (December to March) and the ablation season (July to September). In the proposed

  12. Spatio-temporal analysis of aftershock sequences in terms of Non Extensive Statistical Physics.

    Science.gov (United States)

    Chochlaki, Kalliopi; Vallianatos, Filippos

    2017-04-01

    Earth's seismicity is considered as an extremely complicated process where long-range interactions and fracturing exist (Vallianatos et al., 2016). For this reason, in order to analyze it, we use an innovative methodological approach, introduced by Tsallis (Tsallis, 1988; 2009), named Non Extensive Statistical Physics. This approach introduce a generalization of the Boltzmann-Gibbs statistical mechanics and it is based on the definition of Tsallis entropy Sq, which maximized leads the the so-called q-exponential function that expresses the probability distribution function that maximizes the Sq. In the present work, we utilize the concept of Non Extensive Statistical Physics in order to analyze the spatiotemporal properties of several aftershock series. Marekova (Marekova, 2014) suggested that the probability densities of the inter-event distances between successive aftershocks follow a beta distribution. Using the same data set we analyze the inter-event distance distribution of several aftershocks sequences in different geographic regions by calculating non extensive parameters that determine the behavior of the system and by fitting the q-exponential function, which expresses the degree of non-extentivity of the investigated system. Furthermore, the inter-event times distribution of the aftershocks as well as the frequency-magnitude distribution has been analyzed. The results supports the applicability of Non Extensive Statistical Physics ideas in aftershock sequences where a strong correlation exists along with memory effects. References C. Tsallis, Possible generalization of Boltzmann-Gibbs statistics, J. Stat. Phys. 52 (1988) 479-487. doi:10.1007/BF01016429 C. Tsallis, Introduction to nonextensive statistical mechanics: Approaching a complex world, 2009. doi:10.1007/978-0-387-85359-8. E. Marekova, Analysis of the spatial distribution between successive earthquakes in aftershocks series, Annals of Geophysics, 57, 5, doi:10.4401/ag-6556, 2014 F. Vallianatos, G

  13. BRAZILIAN AMAZONIA DEFORESTATION DETECTION USING SPATIO-TEMPORAL SCAN STATISTICS

    Directory of Open Access Journals (Sweden)

    C. A. O. Vieira

    2012-07-01

    Full Text Available The spatio-temporal models, developed for analyses of diseases, can also be used for others fields of study, including concerns about forest and deforestation. The aim of this paper is to quantitatively check priority areas in order to combat deforestation on the Amazon forest, using the space-time scan statistic. The study area location is at the south of the Amazonas State and cover around 297.183 kilometre squares, including the municipality of Boca do Acre, Labrea, Canutama, Humaita, Manicore, Novo Aripuana e Apui County on the north region of Brazil. This area has showed a significant change for land cover, which has increased the number of deforestation's alerts. Therefore this situation becomes a concern and gets more investigation, trying to stop factors that increase the number of cases in the area. The methodology includes the location and year that deforestation’s alert occurred. These deforestation's alerts are mapped by the DETER (Detection System of Deforestation in Real Time in Amazonia, which is carry out by the Brazilian Space Agency (INPE. The software SatScanTM v7.0 was used in order to define space-time permutation scan statistic for detection of deforestation cases. The outcome of this experiment shows an efficient model to detect space-time clusters of deforestation’s alerts. The model was efficient to detect the location, the size, the order and characteristics about activities at the end of the experiments. Two clusters were considered actives and kept actives up to the end of the study. These clusters are located in Canutama and Lábrea County. This quantitative spatial modelling of deforestation warnings allowed: firstly, identifying actives clustering of deforestation, in which the environment government official are able to concentrate their actions; secondly, identifying historic clustering of deforestation, in which the environment government official are able to monitoring in order to avoid them to became

  14. Amplitude equation approach to spatiotemporal dynamics of cardiac alternans

    Science.gov (United States)

    Echebarria, Blas; Karma, Alain

    2007-11-01

    Amplitude equations are derived that describe the spatiotemporal dynamics of cardiac alternans during periodic pacing of one- [B. Echebarria and A. Karma, Phys. Rev. Lett. 88, 208101 (2002)] and two-dimensional homogeneous tissue and one-dimensional anatomical reentry in a ring of homogeneous tissue. These equations provide a simple physical understanding of arrhythmogenic patterns of period-doubling oscillations of action potential duration with a spatially varying phase and amplitude, as well as explicit quantitative predictions that can be compared to ionic model simulations or experiments. The form of the equations is expected to be valid for a large class of ionic models but the coefficients are derived analytically only for a two-variable ionic model and calculated numerically for the original Noble model of Purkinje fiber action potential. In paced tissue, this theory explains the formation of “spatially discordant alternans” by a linear instability mechanism that produces a periodic pattern of out-of-phase domains of alternans. The wavelength of this pattern, equal to twice the spacing between nodes separating out-of-phase domains, is shown to depend on three fundamental length scales that are determined by the strength of cell-to-cell coupling and conduction velocity (CV) restitution. Moreover, the patterns of alternans can be either stationary, with fixed nodes, or traveling, with moving nodes and hence quasiperiodic oscillations of action potential duration, depending on the relative strength of the destabilizing effect of CV restitution and the stabilizing effect of diffusive coupling. For the ring geometry, we recover the results of Courtemanche, Glass, and Keener [Phys. Rev. Lett. 70, 2182 (1993)] with two important modifications due to cell-to-cell diffusive coupling. First, this coupling breaks the degeneracy of an infinite-dimensional Hopf bifurcation such that the most unstable mode of alternans corresponds to the longest quantized wavelength

  15. Predicting and tracking spatiotemporal moments in electrical resistivity tomography

    Science.gov (United States)

    Ward, W. O. C.; Wilkinson, P. B.; Chambers, J.; Bai, L.

    2015-12-01

    Visualisation is an invaluable tool in the study of near sub-surface processes, whether by mathematical modelling or by geophysical imaging. Quantitative analysis can further assist interpretation of the ongoing physical processes, and it is clear that any reliable model should take direct observations into account. Using electrical resistivity tomography (ERT), localised areas can be surveyed to produce 2-D and 3-D time-lapse images. This study investigates combining quantitative results obtained via ERT with spatio-temporal motion models in tracer experiments to interpret and predict fluid flow. As with any indirect imaging technique, ERT suffers specific issues with resolution and smoothness as a result of its inversion process. In addition, artefacts are typical in the resulting volumes. Mathematical models are also a source of uncertainty - and in combining these with ERT images, a trade-off must be made between the theoretical and the observed. Using computational imaging, distinct regions of stable resistivity can be directly extracted from a time-slice of an ERT volume. The automated nature, as well the potential for more than one region-of-interest, means that multiple regions can be detected. Using Kalman filters, it is possible to convert the detections into a process state, taking into account pre-defined models and predicting progression. In consecutive time-steps, newly detected features are assigned, where possible, to existing predictions to create tracks that match the tracer model. Preliminary studies looked at a simple motion model, tracking the centre of mass of a tracer plume with assumed constant velocity and mean resistivity. Extending the model to factor in spatial distribution of the plume, an oriented semi-axis is used to represent the centralised second-order moment, with an increasing factor of magnitude to represent the plume dispersion. Initial results demonstrate the efficacy of the approach, significantly improving reliability as the

  16. Spatiotemporal analysis of dengue fever in Nepal from 2010 to 2014.

    Science.gov (United States)

    Acharya, Bipin Kumar; Cao, ChunXiang; Lakes, Tobia; Chen, Wei; Naeem, Shahid

    2016-08-22

    Due to recent emergence, dengue is becoming one of the major public health problems in Nepal. The numbers of reported dengue cases in general and the area with reported dengue cases are both continuously increasing in recent years. However, spatiotemporal patterns and clusters of dengue have not been investigated yet. This study aims to fill this gap by analyzing spatiotemporal patterns based on monthly surveillance data aggregated at district. Dengue cases from 2010 to 2014 at district level were collected from the Nepal government's health and mapping agencies respectively. GeoDa software was used to map crude incidence, excess hazard and spatially smoothed incidence. Cluster analysis was performed in SaTScan software to explore spatiotemporal clusters of dengue during the above-mentioned time period. Spatiotemporal distribution of dengue fever in Nepal from 2010 to 2014 was mapped at district level in terms of crude incidence, excess risk and spatially smoothed incidence. Results show that the distribution of dengue fever was not random but clustered in space and time. Chitwan district was identified as the most likely cluster and Jhapa district was the first secondary cluster in both spatial and spatiotemporal scan. July to September of 2010 was identified as a significant temporal cluster. This study assessed and mapped for the first time the spatiotemporal pattern of dengue fever in Nepal. Two districts namely Chitwan and Jhapa were found highly affected by dengue fever. The current study also demonstrated the importance of geospatial approach in epidemiological research. The initial result on dengue patterns and risk of this study may assist institutions and policy makers to develop better preventive strategies.

  17. Spatiotemporal processing in crossmodal interactions for perception of the external world: A review

    Directory of Open Access Journals (Sweden)

    Souta eHidaka

    2015-12-01

    Full Text Available Research regarding crossmodal interactions has garnered much interest in the last few decades. A variety of studies have demonstrated that multisensory information (vision, audition, tactile sensation, and so on can perceptually interact with each other in the spatial and temporal domains. Findings regarding crossmodal interactions in the spatiotemporal domain (i.e., motion processing have also been reported, with updates in the last few years. In this review, we summarize past and recent findings on spatiotemporal processing in crossmodal interactions regarding perception of the external world. A traditional view regarding crossmodal interactions holds that vision is superior to audition in spatial processing, but audition is dominant over vision in temporal processing. Similarly, vision is considered to have dominant effects over the other sensory modalities (i.e., visual capture in spatiotemporal processing. However, recent findings demonstrate that sound could have a driving effect on visual motion perception. Moreover, studies regarding perceptual associative learning reported that, after association is established between a sound sequence without spatial information and visual motion information, the sound sequence could trigger visual motion perception. Other sensory information, such as motor action or smell, has also exhibited similar driving effects on visual motion perception. Additionally, recent brain imaging studies demonstrate that similar activation patterns could be observed in several brain areas, including the motion processing areas, between spatiotemporal information from different sensory modalities. Based on these findings, we suggest that multimodal information could mutually interact in spatiotemporal processing in the percept of the external world and that common perceptual and neural underlying mechanisms would exist for spatiotemporal processing.

  18. Using spatiotemporal statistical models to estimate animal abundance and infer ecological dynamics from survey counts

    Science.gov (United States)

    Conn, Paul B.; Johnson, Devin S.; Ver Hoef, Jay M.; Hooten, Mevin B.; London, Joshua M.; Boveng, Peter L.

    2015-01-01

    Ecologists often fit models to survey data to estimate and explain variation in animal abundance. Such models typically require that animal density remains constant across the landscape where sampling is being conducted, a potentially problematic assumption for animals inhabiting dynamic landscapes or otherwise exhibiting considerable spatiotemporal variation in density. We review several concepts from the burgeoning literature on spatiotemporal statistical models, including the nature of the temporal structure (i.e., descriptive or dynamical) and strategies for dimension reduction to promote computational tractability. We also review several features as they specifically relate to abundance estimation, including boundary conditions, population closure, choice of link function, and extrapolation of predicted relationships to unsampled areas. We then compare a suite of novel and existing spatiotemporal hierarchical models for animal count data that permit animal density to vary over space and time, including formulations motivated by resource selection and allowing for closed populations. We gauge the relative performance (bias, precision, computational demands) of alternative spatiotemporal models when confronted with simulated and real data sets from dynamic animal populations. For the latter, we analyze spotted seal (Phoca largha) counts from an aerial survey of the Bering Sea where the quantity and quality of suitable habitat (sea ice) changed dramatically while surveys were being conducted. Simulation analyses suggested that multiple types of spatiotemporal models provide reasonable inference (low positive bias, high precision) about animal abundance, but have potential for overestimating precision. Analysis of spotted seal data indicated that several model formulations, including those based on a log-Gaussian Cox process, had a tendency to overestimate abundance. By contrast, a model that included a population closure assumption and a scale prior on total

  19. Clustering-Based Approaches to the Exploration of Spatio-Temporal Data

    Science.gov (United States)

    Wu, X.; Zurita-Milla, R.; Kraak, M.-J.; Izquierdo-Verdiguier, E.

    2017-09-01

    As one spatio-temporal data mining task, clustering helps the exploration of patterns in the data by grouping similar elements together. However, previous studies on spatial or temporal clustering are incapable of analysing complex patterns in spatio-temporal data. For instance, concurrent spatio-temporal patterns in 2D or 3D datasets. In this study we present two clustering algorithms for complex pattern analysis: (1) the Bregman block average co-clustering algorithm with I-divergence (BBAC_I) which enables the concurrent analysis of spatio-temporal patterns in 2D data matrix, and (2) the Bregman cube average tri-clustering algorithm with I-divergence (BCAT_I) which enables the complete partitional analysis in 3D data cube. Here the use of the two clustering algorithms is illustrated by Dutch daily average temperature dataset from 28 weather stations from 1992 to 2011. For BBAC_I, it is applied to the averaged yearly dataset to identify station-year co-clusters which contain similar temperatures along stations and years, thus revealing patterns along both spatial and temporal dimensions. For BCAT_I, it is applied to the temperature dataset organized in a data cube with one spatial (stations) and two nested temporal dimensions (years and days). By partitioning the whole dataset into clusters of stations and years with similar within-year temperature similarity, BCATI explores the spatio-temporal patterns of intra-annual variability in the daily temperature dataset. As such, both BBACI and BCATI algorithms, combined with suitable geovisualization techniques, allow the exploration of complex spatial and temporal patterns, which contributes to a better understanding of complex patterns in spatio-temporal data.

  20. Spatiotemporal analysis of dengue fever in Nepal from 2010 to 2014

    Directory of Open Access Journals (Sweden)

    Bipin Kumar Acharya

    2016-08-01

    Full Text Available Abstract Background Due to recent emergence, dengue is becoming one of the major public health problems in Nepal. The numbers of reported dengue cases in general and the area with reported dengue cases are both continuously increasing in recent years. However, spatiotemporal patterns and clusters of dengue have not been investigated yet. This study aims to fill this gap by analyzing spatiotemporal patterns based on monthly surveillance data aggregated at district. Methods Dengue cases from 2010 to 2014 at district level were collected from the Nepal government’s health and mapping agencies respectively. GeoDa software was used to map crude incidence, excess hazard and spatially smoothed incidence. Cluster analysis was performed in SaTScan software to explore spatiotemporal clusters of dengue during the above-mentioned time period. Results Spatiotemporal distribution of dengue fever in Nepal from 2010 to 2014 was mapped at district level in terms of crude incidence, excess risk and spatially smoothed incidence. Results show that the distribution of dengue fever was not random but clustered in space and time. Chitwan district was identified as the most likely cluster and Jhapa district was the first secondary cluster in both spatial and spatiotemporal scan. July to September of 2010 was identified as a significant temporal cluster. Conclusion This study assessed and mapped for the first time the spatiotemporal pattern of dengue fever in Nepal. Two districts namely Chitwan and Jhapa were found highly affected by dengue fever. The current study also demonstrated the importance of geospatial approach in epidemiological research. The initial result on dengue patterns and risk of this study may assist institutions and policy makers to develop better preventive strategies.

  1. Real-time spatiotemporal measurement of ultrafast fields from multimode optical fibers

    Science.gov (United States)

    Guang, Zhe; Rhodes, Michelle; Zhu, Ping; Trebino, Rick

    2017-02-01

    Ultrashort pulses emerging from multimode optical fibers are spatiotemporally complex—the multiple fiber modes have different spatial shapes and different propagation velocities and dispersions inside fibers. To measure the complete spatiotemporal field from multimode fibers in real time, we propose and demonstrate a technique for the complete measurement of these pulses using a simple pulse characterization technique, called Spatially and Temporally Resolved Intensity and Phase Evaluation Device: Full Information from a Single Hologram (STRIPED FISH). It yields the complete electric field vs. space and time from multiple digital holograms, simultaneously recorded at different frequencies on a single camera frame.

  2. Actively tailored spatiotemporal images of quantum interference on the picometer and femtosecond scales.

    Science.gov (United States)

    Katsuki, Hiroyuki; Chiba, Hisashi; Meier, Christoph; Girard, Bertrand; Ohmori, Kenji

    2009-03-13

    Interference fringes of quantum waves weave highly regular space-time images, which could be seen in various wave systems such as wave packets in atoms and molecules, Bose-Einstein condensates, and fermions in a box potential. We have experimentally designed and visualized spatiotemporal images of dynamical quantum interferences of two counterpropagating nuclear wave packets in the iodine molecule; the wave packets are generated with a pair of femtosecond laser pulses whose relative phase is locked within the attosecond time scale. The design of the image has picometer and femtosecond resolutions, and changes drastically as we change the relative phase of the laser pulses, providing a direct spatiotemporal control of quantum interferences.

  3. Mortality in Danish Swine herds: Spatio-temporal clusters and risk factors

    DEFF Research Database (Denmark)

    Lopes Antunes, Ana Carolina; Ersbøll, Annette Kjær; Bihrmann, Kristine

    2017-01-01

    The aim of this study was to explore spatio-temporal mortality patterns in Danish swine herds from December 2013 to October 2015, and to discuss the use of mortality data for syndromic surveillance in Denmark. Although it has previously been assessed within the context of syndromic surveillance......-temporal analysis included data description for spatial, temporal, and spatio-temporal cluster analysis for three age groups: weaners (up to 30 kg), sows and finishers. Logistic regression models were used to assess the potential factors associated with finisher and weaner herds being included within multiple...

  4. Stochastic Modeling of the Spatiotemporal Wavelet Coefficients and Applications to Quality Enhancement and Error Concealment

    Directory of Open Access Journals (Sweden)

    Feideropoulou Georgia

    2004-01-01

    Full Text Available We extend a stochastic model of hierarchical dependencies between wavelet coefficients of still images to the spatiotemporal decomposition of video sequences, obtained by a motion-compensated wavelet decomposition. We propose new estimators for the parameters of this model which provide better statistical performances. Based on this model, we deduce an optimal predictor of missing samples in the spatiotemporal wavelet domain and use it in two applications: quality enhancement and error concealment of scalable video transmitted over packet networks. Simulation results show significant quality improvement achieved by this technique with different packetization strategies for a scalable video bit stream.

  5. Working Collaboratively

    DEFF Research Database (Denmark)

    Holder, Anna; Lovett, George

    2009-01-01

    identified as a transformative global force of the last decade, most notably in knowledge and information publishing, communication and creation. This paper presents a structured conversation on changing understandings of collaboration, and the realities of collaborative methodology in architectural work....... Ideas of the platforms and structures necessary to support ‘creative’ collaborations are advanced and tested, and a vocabulary of key terms is developed. The conversation extends to reflect on the role of the architecture profession in supporting or enabling collaboration in architectural works....

  6. Construction work

    CERN Multimedia

    2004-01-01

    Construction work on building 179 will start on the 16th February 2004 and continue until November 2004. The road between buildings 179 and 158 will temporarily become a one way street from Route Democrite towards building 7. The parking places between buildings 179 and 7 will become obsolete. The ISOLDE collaboration would like to apologize for any inconveniences.

  7. Heart Work

    Science.gov (United States)

    Madden, Sandra R.; Gonzales, Alicia C.

    2017-01-01

    It is not every day that a former student greets a teacher with, "Your course changed my life." The authors are the professor and student of the transformative course. Alicia Gonzales wanted to understand how to work with students to co-construct an environment where persistent problem solving in a technologically rich classroom was the…

  8. Road works

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    GS Department

    2010-01-01

    From Monday 11 October until Friday 29 October 2010, the flow of traffic will be disrupted by road works at the roundabout in front of Restaurant No. 2; The number of spaces available in the car park in front of Rest. No. 2 will be reduced. Thank you for your understanding during this period. GS/SEM Group

  9. Demolition work

    CERN Multimedia

    2004-01-01

    Because of demolition work inside Bldg. 251, two containers will be placed on the route Démocrite. For security reasons, the part of this road in front of barrack 553 will be closed to circulation from 5 to 12 November. Thank you, in advance for your understanding. PH-SMI

  10. Wetlands Work

    Science.gov (United States)

    Messina, Linda; Blanchard, Pamela Borne

    2004-01-01

    This article describes how a biology teacher's search for a cross-curricular project in science, math, history, and environmental science, that would help her students connect what they were learning in the classroom to their everyday life, resulted in an ongoing stewardship project. Working together with the Louisiana Sea Grant College Program…

  11. Spatio-temporal keyword queries in social networks

    DEFF Research Database (Denmark)

    Cozza, V.; Messina, Alessandro; Montesi, D.

    2013-01-01

    Due to the large amount of social network data produced at an ever growing speed and their complex nature, recent works have addressed the problem of efficiently querying such data according to social, temporal or spatial dimensions. In this work we propose a data model that keeps into account all...

  12. Attribute Invariant Spatial and Spatio-Temporal Correlators

    Science.gov (United States)

    Monjur, Mehjabin Sultana

    PMT based correlators. We also develop the concept and design of an Automatic Event Recognition (AER) System based on a three-dimensional Spatio-Temporal Correlator (STC), that combines the techniques of holographic correlation and photon echo based temporal pattern recognition to match a video-clip contained in a video file, using atoms stored in a porous-glass material. By employing the nonlinear properties of inhomogenous broadened atomic media we show that it is possible to realize an AER system that can recognize rapidly the occurrence of events, the number of events, and the occurrence times. To model the response of such a system, one requires solving the Schrodinger Equation (SE), which is a computationally extensive task. We develop an analytical model to find the response of the STC and show that the analytical model agrees closely with the results obtained via explicit numerical simulation, but at a speed that is many orders of magnitude faster than the numerical model. We also show how such a practical AER system can be realized using a combination of a porous-glass based Rb vapor cell, a holographic video disc, and a lithium niobate crystal.

  13. Standardization work

    Science.gov (United States)

    Malavallon, Olivier

    1995-04-01

    For several years now, the main civil aircraft manufacturers (Airbus and its partners, Boeing, Fokker, McDonnell Douglas) have been working jointly on the writing of technical recommendations and the drawing up of an international standard. This work concerns the evaluation of the processes and products used to strip aeronautical paint systems. This procedure was initiated on request from the main airlines. In effect, the airlines are faced with situations in which the financial and operational objectives are becoming increasingly important. The need was felt to rationalize and, if possible, harmonize the criteria and technical requirements of the various civil aircraft manufacturers in order to facilitate in-service maintenance of the fleets of airlines operating Airbus, Boeing, Douglas aircraft, etc.

  14. Working memory.

    Science.gov (United States)

    Baddeley, A

    1992-01-31

    The term working memory refers to a brain system that provides temporary storage and manipulation of the information necessary for such complex cognitive tasks as language comprehension, learning, and reasoning. This definition has evolved from the concept of a unitary short-term memory system. Working memory has been found to require the simultaneous storage and processing of information. It can be divided into the following three subcomponents: (i) the central executive, which is assumed to be an attentional-controlling system, is important in skills such as chess playing and is particularly susceptible to the effects of Alzheimer's disease; and two slave systems, namely (ii) the visuospatial sketch pad, which manipulates visual images and (iii) the phonological loop, which stores and rehearses speech-based information and is necessary for the acquisition of both native and second-language vocabulary.

  15. Works notice

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    GS Department

    2009-01-01

    We would like to inform you that renovation work on the road lighting equipment will take place on the Meyrin site between 19 October and 18 December 2009. During this period, traffic will be disrupted on the Schrödinger, Perrin and Siegbahn roads, ie from Building 274 to Building 188. We request that you comply with the road signs and thank you for your understanding. GS-SEM Group

  16. RESUMING WORK

    CERN Multimedia

    Medical Service

    2002-01-01

    In application of the Staff Rules and Regulations, every member of the CERN personnel is required to undergo a medical examination on resuming work after sick leave: if the medical absence has been for 21 calendar days or longer, if absent more than 48 hours due to professional accident. It is incumbent upon the member of the personnel himself/herself to contact the Medical Service 73186, without awaiting its summons. Medical Service

  17. RESUMING WORK

    CERN Multimedia

    Medical Service

    2001-01-01

    In application of the Staff Rules and Regulations, every member of the CERN personnel is required to undergo a medical examination on resuming work after sick leave: if the medical absence has been for 21 calendar days or longer, if absent more than 48 hours due to professional accident. It is incumbent upon the member of the personnel himself/herself to contact the Medical Service 73186, without awaiting its summons.

  18. A FRAMEWORK FOR ONLINE SPATIO-TEMPORAL DATA VISUALIZATION BASED ON HTML5

    Directory of Open Access Journals (Sweden)

    B. Mao

    2012-07-01

    Full Text Available Web is entering a new phase – HTML5. New features of HTML5 should be studied for online spatio-temporal data visualization. In the proposed framework, spatio-temporal data is stored in the data server and is sent to user browsers with WebSocket. Public geo-data such as Internet digital map is integrated into the browsers. Then animation is implemented through the canvas object defined by the HTML5 specification. To simulate the spatio-temporal data source, we collected the daily location of 15 users with GPS tracker. The current positions of the users are collected every minute and are recorded in a file. Based on this file, we generate a real time spatio-temporal data source which sends out current user location every second.By enlarging the real time scales by 60 times, we can observe the movement clearly. The data transmitted with WebSocket is the coordinates of users' current positions, which will can be demonstrated in client browsers.

  19. Probabilistic M/EEG source imaging from sparse spatio-temporal event structure

    DEFF Research Database (Denmark)

    Stahlhut, Carsten; Attias, Hagai T.; Wipf, David

    While MEG and EEG source imaging methods have to tackle a severely ill-posed problem their success can be stated as their ability to constrain the solutions using appropriate priors. In this paper we propose a hierarchical Bayesian model facilitating spatio-temporal patterns through the use of both...

  20. Spatio-temporal variability of hyporheic exchange through a pool-riffle-pool sequence

    Science.gov (United States)

    Frank P. Gariglio; Daniele Tonina; Charles H. Luce

    2013-01-01

    Stream water enters and exits the streambed sediment due to hyporheic fluxes, which stem primarily from the interaction between surface water hydraulics and streambed morphology. These fluxes sustain a rich ecotone, whose habitat quality depends on their direction and magnitude. The spatio-temporal variability of hyporheic fluxes is not well understood over several...