Sample records for visual search patterns

  1. A Temporal Pattern Search Algorithm for Personal History Event Visualization

    E-print Network

    Shneiderman, Ben

    focused on temporal events and their temporal patterns in a variety of domains: health care and electronic1 A Temporal Pattern Search Algorithm for Personal History Event Visualization Taowei David Wang algorithm for searching for temporal patterns of events in historical personal histories. The traditional

  2. NCI Visuals Online: Search

    Cancer.gov

    Skip Navigation NCI Visuals Online Home About My Pictures Browse Search Quick Search Search Search for: Date Created: Any 1900 1920 1940 1960 1980 1990 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 to Any 1900 1920 1940 1960 1980 1990 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Sort

  3. Visual Search Jeremy M. Wolfe

    E-print Network

    and red, both features can guide attention. Some of the rules of the human visual search engine10 Visual Search Jeremy M. Wolfe Abstract This chapter considers the range of visual search tasks, from those involving very brief- ly presented stimuli to those involving search processes that extend

  4. Randomized Pattern Search

    Microsoft Academic Search

    J. P. Lawrence; Kenneth Steiglitz

    1972-01-01

    A random search technique for function minimization is proposed that incorporates the step-size and direction adaptivity of Hooke and Jeeves' [1] pattern search. Experimental results for a variety of functions indicate that the random pattern search is more effective than the corresponding deterministic method for a class of problems with hard constraints.

  5. Visual Pattern Discrimination

    Microsoft Academic Search

    B. Julesz

    1962-01-01

    Visual discrimination experiments were conducted using unfamiliar displays generated by a digital computer. The displays contained two side-by-side fields with different statistical, topological or heuristic properties. Discrimination was defined as that spontaneous visual process which gives the immediate impression of two distinct fields. The condition for such discrimination was found to be based primarily on clusters or lines formed by

  6. Pandemonium and visual search.

    PubMed

    Henderson, L

    1978-01-01

    Pandemonium-like models have played a central role in theories of perceptual recognition. One model is examined which asserts that information is sorted unidirectionally through a hierarchy of increasingly abstract levels only to a depth required by the logical demands of the task and read off from the appropriate level to control response decisions. The support originally claimed for the model in terms of its application to visual search performance is questioned. It is suggested that the pervasiveness of such models is not due to their competition with alternative theories but rather to methatheoretic considerations. PMID:628586

  7. Visualizing search results: evaluating an iconic visualization

    NASA Astrophysics Data System (ADS)

    Erfani Joorabchi, M.; Dalvandi, A.; Seifi, H.; Bartram, L.; Shaw, C. D.

    2010-01-01

    Commercial websites offer many items to potential site users. However, most current websites display results of a search in text lists, or as lists sorted on one or two single criteria. Finding the best item in a text list based on multi-priority criteria is an exhausting task, especially for long lists. Visualizing search results and enabling users to perceive the tradeoffs among the results based on multiple priorities may ease this process. To investigate this, two different techniques for displaying and sorting search results are studied in this paper; Text, and XY Iconic Visualization. The goal is to determine which technique for representing search results would be the most efficient one for a website user. We conducted a user study to compare the usability of the two techniques. Collected data is in the form of participants' task responses, a satisfaction questionnaire, qualitative observations, and participants' comments. According to the results, iconic visualization is better for overview (it gives a good overview in a short amount of time) and search with more than two criteria, while text-based performs better for displaying details.

  8. Innate Visual Learning through Spontaneous Activity Patterns

    Microsoft Academic Search

    Mark V. Albert; Adam Schnabel; David J. Field

    2008-01-01

    Patterns of spontaneous activity in the developing retina, LGN, and cortex are necessary for the proper development of visual cortex. With these patterns intact, the primary visual cortices of many newborn animals develop properties similar to those of the adult cortex but without the training benefit of visual experience. Previous models have demonstrated how V1 responses can be initialized through

  9. Development of a Computerized Visual Search Test

    ERIC Educational Resources Information Center

    Reid, Denise; Babani, Harsha; Jon, Eugenia

    2009-01-01

    Visual attention and visual search are the features of visual perception, essential for attending and scanning one's environment while engaging in daily occupations. This study describes the development of a novel web-based test of visual search. The development information including the format of the test will be described. The test was designed…

  10. Asymmetries in visual search: An introduction

    Microsoft Academic Search

    Jeremy M. Wolfe

    2001-01-01

    In visual search tasks, observers look for a target stimulus among distractor stimuli. A visual search asymmetry is said to\\u000a occur when a search for stimulus A among stimulus B produces different results from a search for B among A. Anne Treisman\\u000a made search asymmetries into an important tool in the study of visual attention. She argued that it was

  11. Characteristic sounds facilitate visual search.

    PubMed

    Iordanescu, Lucica; Guzman-Martinez, Emmanuel; Grabowecky, Marcia; Suzuki, Satoru

    2008-06-01

    In a natural environment, objects that we look for often make characteristic sounds. A hiding cat may meow, or the keys in the cluttered drawer may jingle when moved. Using a visual search paradigm, we demonstrated that characteristic sounds facilitated visual localization of objects, even when the sounds carried no location information. For example, finding a cat was faster when participants heard a meow sound. In contrast, sounds had no effect when participants searched for names rather than pictures of objects. For example, hearing "meow" did not facilitate localization of the word cat. These results suggest that characteristic sounds cross-modally enhance visual (rather than conceptual) processing of the corresponding objects. Our behavioral demonstration of object-based cross-modal enhancement complements the extensive literature on space-based cross-modal interactions. When looking for your keys next time, you might want to play jingling sounds. PMID:18567253

  12. Visual Templates in Pattern Generalization Activity

    ERIC Educational Resources Information Center

    Rivera, F. D.

    2010-01-01

    In this research article, I present evidence of the existence of visual templates in pattern generalization activity. Such templates initially emerged from a 3-week design-driven classroom teaching experiment on pattern generalization involving linear figural patterns and were assessed for existence in a clinical interview that was conducted four…

  13. A visual tool for using design patterns as pattern languages

    Microsoft Academic Search

    Paloma Díaz; Ignacio Aedo; Mary Beth Rosson; John M. Carroll

    2010-01-01

    Design patterns document successful solutions to recurrent problems in a specific software development domain. However, finding the patterns you need can be difficult, often requiring the designer to comprehend a long narrative description to understand the benefits, implications and trade-offs of each pattern and of its relationships with others. In this paper we propose a visual notation supported by a

  14. Visual Field Screening System by Using Overlapped Fixation Patterns

    NASA Astrophysics Data System (ADS)

    Kotani, Kentaro; Yoshikawa, Ryota; Tamura, Toshiki; Asao, Takafumi; Sugiyama, Tetsuya; Ueki, Mari; Kojima, Shota; Shibata, Maho; Ikeda, Tsunehiko

    This study introduces a novel technique for estimating visual field by using overlapped fixation patterns obtained by amounts of displacement in voluntary eye movements during searching-tracking trials, as an alternative screening medical device for visual field examination. Proposed system was evaluated by glaucoma patients, in order to study whether or not the proposed system can be used as a visual field detection device for screening. As a result, the proposed system detected the visual field abnormality to a certain extent. However, there were some cases that detection of Mariotte blind spots was inaccurately performed. The experimental results revealed that there was room to reconsider our understanding regarding the effect of ptosis, overlapped with eye sight as well as calibration of the display position to the correct location to be examined. Results of the evaluation experiment indicated that this proposed system has a potential to be used as a visual field examination device for screening.

  15. Effects of Peripheral Visual Field Loss on Eye Movements During Visual Search

    PubMed Central

    Wiecek, Emily; Pasquale, Louis R.; Fiser, Jozsef; Dakin, Steven; Bex, Peter J.

    2012-01-01

    Natural vision involves sequential eye movements that bring the fovea to locations selected by peripheral vision. How peripheral visual field loss (PVFL) affects this process is not well understood. We examine how the location and extent of PVFL affects eye movement behavior in a naturalistic visual search task. Ten patients with PVFL and 13 normally sighted subjects with full visual fields (FVF) completed 30 visual searches monocularly. Subjects located a 4°?×?4° target, pseudo-randomly selected within a 26°?×?11° natural image. Eye positions were recorded at 50?Hz. Search duration, fixation duration, saccade size, and number of saccades per trial were not significantly different between PVFL and FVF groups (p?>?0.1). A ?2 test showed that the distributions of saccade directions for PVFL and FVL subjects were significantly different in 8 out of 10 cases (p?Visual Field pattern deviations for each subject were compared with the spatial distribution of eye movement directions. There were no significant correlations between saccade directional bias and visual field sensitivity across the 10 patients. Visual search performance was not significantly affected by PVFL. An analysis of eye movement directions revealed patients with PVFL show a biased directional distribution that was not directly related to the locus of vision loss, challenging feed-forward models of eye movement control. Consequently, many patients do not optimally compensate for visual field loss during visual search. PMID:23162511

  16. Statistical templates for visual search.

    PubMed

    Ackermann, John F; Landy, Michael S

    2014-01-01

    How do we find a target embedded in a scene? Within the framework of signal detection theory, this task is carried out by comparing each region of the scene with a "template," i.e., an internal representation of the search target. Here we ask what form this representation takes when the search target is a complex image with uncertain orientation. We examine three possible representations. The first is the matched filter. Such a representation cannot account for the ease with which humans can find a complex search target that is rotated relative to the template. A second representation attempts to deal with this by estimating the relative orientation of target and match and rotating the intensity-based template. No intensity-based template, however, can account for the ability to easily locate targets that are defined categorically and not in terms of a specific arrangement of pixels. Thus, we define a third template that represents the target in terms of image statistics rather than pixel intensities. Subjects performed a two-alternative, forced-choice search task in which they had to localize an image that matched a previously viewed target. Target images were texture patches. In one condition, match images were the same image as the target and distractors were a different image of the same textured material. In the second condition, the match image was of the same texture as the target (but different pixels) and the distractor was an image of a different texture. Match and distractor stimuli were randomly rotated relative to the target. We compared human performance to pixel-based, pixel-based with rotation, and statistic-based search models. The statistic-based search model was most successful at matching human performance. We conclude that humans use summary statistics to search for complex visual targets. PMID:24627458

  17. Statistical templates for visual search

    PubMed Central

    Ackermann, John F.; Landy, Michael S.

    2014-01-01

    How do we find a target embedded in a scene? Within the framework of signal detection theory, this task is carried out by comparing each region of the scene with a “template,” i.e., an internal representation of the search target. Here we ask what form this representation takes when the search target is a complex image with uncertain orientation. We examine three possible representations. The first is the matched filter. Such a representation cannot account for the ease with which humans can find a complex search target that is rotated relative to the template. A second representation attempts to deal with this by estimating the relative orientation of target and match and rotating the intensity-based template. No intensity-based template, however, can account for the ability to easily locate targets that are defined categorically and not in terms of a specific arrangement of pixels. Thus, we define a third template that represents the target in terms of image statistics rather than pixel intensities. Subjects performed a two-alternative, forced-choice search task in which they had to localize an image that matched a previously viewed target. Target images were texture patches. In one condition, match images were the same image as the target and distractors were a different image of the same textured material. In the second condition, the match image was of the same texture as the target (but different pixels) and the distractor was an image of a different texture. Match and distractor stimuli were randomly rotated relative to the target. We compared human performance to pixel-based, pixel-based with rotation, and statistic-based search models. The statistic-based search model was most successful at matching human performance. We conclude that humans use summary statistics to search for complex visual targets. PMID:24627458

  18. The development of organized visual search

    PubMed Central

    Woods, Adam J.; Goksun, Tilbe; Chatterjee, Anjan; Zelonis, Sarah; Mehta, Anika; Smith, Sabrina E.

    2013-01-01

    Visual search plays an important role in guiding behavior. Children have more difficulty performing conjunction search tasks than adults. The present research evaluates whether developmental differences in children's ability to organize serial visual search (i.e., search organization skills) contribute to performance limitations in a typical conjunction search task. We evaluated 134 children between the ages of 2 and 17 on separate tasks measuring search for targets defined by a conjunction of features or by distinct features. Our results demonstrated that children organize their visual search better as they get older. As children's skills at organizing visual search improve they become more accurate at locating targets with conjunction of features amongst distractors, but not for targets with distinct features. Developmental limitations in children's abilities to organize their visual search of the environment are an important component of poor conjunction search in young children. In addition, our findings provide preliminary evidence that, like other visuospatial tasks, exposure to reading may influence children's spatial orientation to the visual environment when performing a visual search. PMID:23584560

  19. Beyond the Search Surface: Visual Search and Attentional Engagement

    Microsoft Academic Search

    John Duncan; Glyn Humphreys

    1992-01-01

    Treisman (1991) described a series of visual search studies testing feature integration theory against an alternative (Duncan & Humphreys, 1989) in which feature and conjunction search are basically similar. Here the latter account is noted to have 2 distinct levels: (a) a summary of search findings in terms of stimulus similarities, and (b) a theory of how visual attention is

  20. Innate Visual Learning through Spontaneous Activity Patterns

    PubMed Central

    Albert, Mark V.; Schnabel, Adam; Field, David J.

    2008-01-01

    Patterns of spontaneous activity in the developing retina, LGN, and cortex are necessary for the proper development of visual cortex. With these patterns intact, the primary visual cortices of many newborn animals develop properties similar to those of the adult cortex but without the training benefit of visual experience. Previous models have demonstrated how V1 responses can be initialized through mechanisms specific to development and prior to visual experience, such as using axonal guidance cues or relying on simple, pairwise correlations on spontaneous activity with additional developmental constraints. We argue that these spontaneous patterns may be better understood as part of an “innate learning” strategy, which learns similarly on activity both before and during visual experience. With an abstraction of spontaneous activity models, we show how the visual system may be able to bootstrap an efficient code for its natural environment prior to external visual experience, and we continue the same refinement strategy upon natural experience. The patterns are generated through simple, local interactions and contain the same relevant statistical properties of retinal waves and hypothesized waves in the LGN and V1. An efficient encoding of these patterns resembles a sparse coding of natural images by producing neurons with localized, oriented, bandpass structure—the same code found in early visual cortical cells. We address the relevance of higher-order statistical properties of spontaneous activity, how this relates to a system that may adapt similarly on activity prior to and during natural experience, and how these concepts ultimately relate to an efficient coding of our natural world. PMID:18670593

  1. Collinearity Impairs Local Element Visual Search

    ERIC Educational Resources Information Center

    Jingling, Li; Tseng, Chia-Huei

    2013-01-01

    In visual searches, stimuli following the law of good continuity attract attention to the global structure and receive attentional priority. Also, targets that have unique features are of high feature contrast and capture attention in visual search. We report on a salient global structure combined with a high orientation contrast to the…

  2. Cue Search and Comparison Processes in Visual Search for

    E-print Network

    Logan, Gordon D.

    information relevant to com- parison may be gained before cue search finishes. Indeed, the two explanationsCue Search and Comparison Processes in Visual Search for Letters* GORDON D. LOGAN Erindale College, subjects searched four- and eight-letter arrays for the presence of a T or an F. The position of the target

  3. Searching social networks for subgraph patterns

    NASA Astrophysics Data System (ADS)

    Ogaard, Kirk; Kase, Sue; Roy, Heather; Nagi, Rakesh; Sambhoos, Kedar; Sudit, Moises

    2013-06-01

    Software tools for Social Network Analysis (SNA) are being developed which support various types of analysis of social networks extracted from social media websites (e.g., Twitter). Once extracted and stored in a database such social networks are amenable to analysis by SNA software. This data analysis often involves searching for occurrences of various subgraph patterns (i.e., graphical representations of entities and relationships). The authors have developed the Graph Matching Toolkit (GMT) which provides an intuitive Graphical User Interface (GUI) for a heuristic graph matching algorithm called the Truncated Search Tree (TruST) algorithm. GMT is a visual interface for graph matching algorithms processing large social networks. GMT enables an analyst to draw a subgraph pattern by using a mouse to select categories and labels for nodes and links from drop-down menus. GMT then executes the TruST algorithm to find the top five occurrences of the subgraph pattern within the social network stored in the database. GMT was tested using a simulated counter-insurgency dataset consisting of cellular phone communications within a populated area of operations in Iraq. The results indicated GMT (when executing the TruST graph matching algorithm) is a time-efficient approach to searching large social networks. GMT's visual interface to a graph matching algorithm enables intelligence analysts to quickly analyze and summarize the large amounts of data necessary to produce actionable intelligence.

  4. SOME TEMPORAL CHARACTERISTICS OF VISUAL PATTERN PERCEPTION

    Microsoft Academic Search

    CHARLES W. ERIKSEN; JAMES F. COLLINS

    1967-01-01

    VISUAL STIMULI WERE CONSTRUCTED SO THAT ANY GIVEN STIMULUS BY ITSELF APPEARED TO BE A RANDOM COLLECTION OF DOTS. HOWEVER, WHEN 2 CORRESPONDING STIMULI WERE SUPERIMPOSED BY MEANS OF A 2-FIELD TACHISTOSCOPE, A 3-LETTER NONSENSE SYLLABLE WAS PERCEIVED. TEMPORAL ORGANIZATION IN PERCEPTION WAS STUDIED IN EXP. I BY VARYING THE INTERVAL BETWEEN THE PRESENTATION OF THE 2 CORRESPONDING PATTERNS OVER

  5. Execution patterns for visualizing web services

    Microsoft Academic Search

    Wim De Pauw; Sophia Krasikov; John F. Morar

    2006-01-01

    Web Services are well on their way to becoming the Lingua Franca for distributed computing. Although tools for building and monitoring web services applications are more powerful and easier to use than ever, they do not yet fully address the horizontal complexity of mature applications built as large nets of interconnected web services. We present a pattern-based visualization that enables

  6. Frontal–Occipital Connectivity During Visual Search

    PubMed Central

    Pantazatos, Spiro P.; Yanagihara, Ted K.; Zhang, Xian; Meitzler, Thomas

    2012-01-01

    Abstract Although expectation- and attention-related interactions between ventral and medial prefrontal cortex and stimulus category-selective visual regions have been identified during visual detection and discrimination, it is not known if similar neural mechanisms apply to other tasks such as visual search. The current work tested the hypothesis that high-level frontal regions, previously implicated in expectation and visual imagery of object categories, interact with visual regions associated with object recognition during visual search. Using functional magnetic resonance imaging, subjects searched for a specific object that varied in size and location within a complex natural scene. A model-free, spatial-independent component analysis isolated multiple task-related components, one of which included visual cortex, as well as a cluster within ventromedial prefrontal cortex (vmPFC), consistent with the engagement of both top-down and bottom-up processes. Analyses of psychophysiological interactions showed increased functional connectivity between vmPFC and object-sensitive lateral occipital cortex (LOC), and results from dynamic causal modeling and Bayesian Model Selection suggested bidirectional connections between vmPFC and LOC that were positively modulated by the task. Using image-guided diffusion-tensor imaging, functionally seeded, probabilistic white-matter tracts between vmPFC and LOC, which presumably underlie this effective interconnectivity, were also observed. These connectivity findings extend previous models of visual search processes to include specific frontal–occipital neuronal interactions during a natural and complex search task. PMID:22708993

  7. Driving forces in free visual search: An ethology.

    PubMed

    MacInnes, W Joseph; Hunt, Amelia R; Hilchey, Matthew D; Klein, Raymond M

    2014-02-01

    Visual search typically involves sequences of eye movements under the constraints of a specific scene and specific goals. Visual search has been used as an experimental paradigm to study the interplay of scene salience and top-down goals, as well as various aspects of vision, attention, and memory, usually by introducing a secondary task or by controlling and manipulating the search environment. An ethology is a study of an animal in its natural environment, and here we examine the fixation patterns of the human animal searching a series of challenging illustrated scenes that are well-known in popular culture. The search was free of secondary tasks, probes, and other distractions. Our goal was to describe saccadic behavior, including patterns of fixation duration, saccade amplitude, and angular direction. In particular, we employed both new and established techniques for identifying top-down strategies, any influences of bottom-up image salience, and the midlevel attentional effects of saccadic momentum and inhibition of return. The visual search dynamics that we observed and quantified demonstrate that saccades are not independently generated and incorporate distinct influences from strategy, salience, and attention. Sequential dependencies consistent with inhibition of return also emerged from our analyses. PMID:24385137

  8. Visual search engine for product images

    NASA Astrophysics Data System (ADS)

    Lin, Xiaofan; Gokturk, Burak; Sumengen, Baris; Vu, Diem

    2008-01-01

    Nowadays there are many product comparison web sites. But most of them only use text information. This paper introduces a novel visual search engine for product images, which provides a brand-new way of visually locating products through Content-based Image Retrieval (CBIR) technology. We discusses the unique technical challenges, solutions, and experimental results in the design and implementation of this system.

  9. Pattern Search Algorithms for Bound Constrained Minimization

    NASA Technical Reports Server (NTRS)

    Lewis, Robert Michael; Torczon, Virginia

    1996-01-01

    We present a convergence theory for pattern search methods for solving bound constrained nonlinear programs. The analysis relies on the abstract structure of pattern search methods and an understanding of how the pattern interacts with the bound constraints. This analysis makes it possible to develop pattern search methods for bound constrained problems while only slightly restricting the flexibility present in pattern search methods for unconstrained problems. We prove global convergence despite the fact that pattern search methods do not have explicit information concerning the gradient and its projection onto the feasible region and consequently are unable to enforce explicitly a notion of sufficient feasible decrease.

  10. Detection of multidimensional targets in visual search

    Microsoft Academic Search

    Patrick Monnier

    2006-01-01

    Search performance for targets defined along multiple dimensions was investigated with an accuracy visual search task. Initially, threshold was measured for targets that differed from homogeneous distractors along a single dimension (e.g., a reddish target among achromatic distractors, or a right-tilted target among vertically oriented distractors). Threshold was then measured for a multidimension- al target (a redundant target) that differed

  11. Search Results using Timeline Visualizations Omar Alonso

    E-print Network

    Gertz, Michael

    Search Results using Timeline Visualizations Omar Alonso Dept. of Computer Science University a new approach in which search results are arranged in a well-defined timeline using a few existing based on the Gregorian Calendar, with a single day being an atomic time interval called chronon. Our

  12. Visually distinct patterns with matching subband statistics.

    PubMed

    Gluckman, Joshua

    2005-02-01

    A commonly used representation of a visual pattern is a statistical distribution measured from the output of a bank of filters (Gaussian, Laplacian, Gabor, etc.). Both marginal and joint distributions of filter responses have been advocated and effectively used for a variety of vision tasks, including texture classification, texture synthesis, object detection, and image retrieval. This paper examines the ability of these representations to discriminate between an arbitrary pair of visual stimuli. Examples of patterns are derived that provably possess the same marginal and joint statistical properties, yet are "visually distinct." This is accomplished by showing sufficient conditions for matching the first k moments of the marginal distributions of a pair of images. Then, given a set of filters, we show how to match the marginal statistics of the subband images formed through convolution with the filter set. Next, joint statistics are examined and images with similar joint distributions of subband responses are shown. Finally, distinct periodic patterns are derived that possess approximately the same subband statistics for any arbitrary filter set. PMID:15688562

  13. ASYNCHRONOUS PARALLEL PATTERN SEARCH FOR NONLINEAR OPTIMIZATION

    E-print Network

    Kolda, Tamara G.

    ASYNCHRONOUS PARALLEL PATTERN SEARCH FOR NONLINEAR OPTIMIZATION PATRICIA D. HOUGH, TAMARA G. KOLDA. 1, pp. 134­156 Abstract. We introduce a new asynchronous parallel pattern search (APPS). Parallel pattern search can be quite useful for engineering optimization problems characterized by a small number

  14. ASYNCHRONOUS PARALLEL PATTERN SEARCH FOR NONLINEAR OPTIMIZATION #

    E-print Network

    Kolda, Tamara G.

    ASYNCHRONOUS PARALLEL PATTERN SEARCH FOR NONLINEAR OPTIMIZATION # PATRICIA D. HOUGH + , TAMARA G Mathematics Vol. 23, No. 1, pp. 134--156 Abstract. We introduce a new asynchronous parallel pattern search (APPS). Parallel pattern search can be quite useful for engineering optimization problems characterized

  15. Conditional probability modulates visual search efficiency

    PubMed Central

    Cort, Bryan; Anderson, Britt

    2013-01-01

    We investigated the effects of probability on visual search. Previous work has shown that people can utilize spatial and sequential probability information to improve target detection. We hypothesized that performance improvements from probability information would extend to the efficiency of visual search. Our task was a simple visual search in which the target was always present among a field of distractors, and could take one of two colors. The absolute probability of the target being either color was 0.5; however, the conditional probability—the likelihood of a particular color given a particular combination of two cues—varied from 0.1 to 0.9. We found that participants searched more efficiently for high conditional probability targets and less efficiently for low conditional probability targets, but only when they were explicitly informed of the probability relationship between cues and target color. PMID:24146645

  16. Features in visual search combine linearly

    PubMed Central

    Pramod, R. T.; Arun, S. P.

    2014-01-01

    Single features such as line orientation and length are known to guide visual search, but relatively little is known about how multiple features combine in search. To address this question, we investigated how search for targets differing in multiple features (intensity, length, orientation) from the distracters is related to searches for targets differing in each of the individual features. We tested race models (based on reaction times) and co-activation models (based on reciprocal of reaction times) for their ability to predict multiple feature searches. Multiple feature searches were best accounted for by a co-activation model in which feature information combined linearly (r = 0.95). This result agrees with the classic finding that these features are separable i.e., subjective dissimilarity ratings sum linearly. We then replicated the classical finding that the length and width of a rectangle are integral features—in other words, they combine nonlinearly in visual search. However, to our surprise, upon including aspect ratio as an additional feature, length and width combined linearly and this model outperformed all other models. Thus, length and width of a rectangle became separable when considered together with aspect ratio. This finding predicts that searches involving shapes with identical aspect ratio should be more difficult than searches where shapes differ in aspect ratio. We confirmed this prediction on a variety of shapes. We conclude that features in visual search co-activate linearly and demonstrate for the first time that aspect ratio is a novel feature that guides visual search. PMID:24715328

  17. Recollection can support hybrid visual memory search.

    PubMed

    Guild, Emma B; Cripps, Jenna M; Anderson, Nicole D; Al-Aidroos, Naseem

    2014-02-01

    On a daily basis, we accomplish the task of searching our visual environment for one of a number of possible objects, like searching for any one of our friends in a crowd, and we do this with ease. Understanding how attention, perception, and long-term memory interact to accomplish this process remains an important question. Recent research (Wolfe in Psychological Science 23:698-703, 2012) has shown that increasing the number of possible targets one is searching for adds little cost to the efficiency of visual search-specifically, that response times increase logarithmically with memory set size. It is unclear, however, what type of recognition memory process (familiarity or recollection) supports a hybrid visual memory search. Previous hybrid search paradigms create conditions that allow participants to rely on the familiarity of perceptually identical targets. In two experiments, we show that hybrid search remains efficient even when the familiarity of targets is minimized (Experiment 1) and when participants are encouraged to flexibly retrieve target information that is perceptually distinct from the information previously studied (Experiment 2). We propose that such efficient and flexible performance on a hybrid search task may engage a rapid from of recollection (Moscovitch in Canadian Journal of Experimental Psychology 62:62-79, 2008). We discuss possible neural correlates supporting simultaneous perception, comparison of incoming information, and recollection of episodic memories. PMID:23884688

  18. Vocal Dynamic Visual Pattern for voice characterization

    NASA Astrophysics Data System (ADS)

    Dajer, M. E.; Andrade, F. A. S.; Montagnoli, A. N.; Pereira, J. C.; Tsuji, D. H.

    2011-12-01

    Voice assessment requires simple and painless exams. Modern technologies provide the necessary resources for voice signal processing. Techniques based on nonlinear dynamics seem to asses the complexity of voice more accurately than other methods. Vocal dynamic visual pattern (VDVP) is based on nonlinear methods and provides qualitative and quantitative information. Here we characterize healthy and Reinke's edema voices by means of perturbation measures and VDVP analysis. VDPD and jitter show different results for both groups, while amplitude perturbation has no difference. We suggest that VDPD analysis improve and complement the evaluation methods available for clinicians.

  19. Auditory psychomotor coordination and visual search performance

    Microsoft Academic Search

    David R. Perrott; Kourosh Saberi; Kathleen Brown; Thomas Z. Strybel

    1990-01-01

    In Experiments 1 and 2, the time to locate and identify a visual target (visual search performance in a two-alternative forced-choice\\u000a paradigm) was measured as a function of the location of the target relative to the subject’s initial line of gaze. In Experiment\\u000a 1, tests were conducted within a 260° region on the horizontal plane at a fixed elevation (eye

  20. Semantic category effects in visual word search

    Microsoft Academic Search

    Martin B. Karlin; Gordon H. Bower

    1976-01-01

    The initial question was whether subjects could categorize a word semantically before they precisely identified the word itself.\\u000a This failed to occur. When searching a visual display for a single target word, subjects searched at the same rate whether\\u000a the distractors were in the same or in a different semantic category. However, when the size of the target set was

  1. Visual pattern recognition in Drosophila is invariant for retinal position.

    PubMed

    Tang, Shiming; Wolf, Reinhard; Xu, Shuping; Heisenberg, Martin

    2004-08-13

    Vision relies on constancy mechanisms. Yet, these are little understood, because they are difficult to investigate in freely moving organisms. One such mechanism, translation invariance, enables organisms to recognize visual patterns independent of the region of their visual field where they had originally seen them. Tethered flies (Drosophila melanogaster) in a flight simulator can recognize visual patterns. Because their eyes are fixed in space and patterns can be displayed in defined parts of their visual field, they can be tested for translation invariance. Here, we show that flies recognize patterns at retinal positions where the patterns had not been presented before. PMID:15310908

  2. Visualizing Search Behavior with Adaptive Discriminations

    PubMed Central

    Cook, Robert G.; Qadri, Muhammad A. J.

    2014-01-01

    We examined different aspects of the visual search behavior of a pigeon using an open-ended, adaptive testing procedure controlled by a genetic algorithm. The animal had to accurately search for and peck a gray target element randomly located from among a variable number of surrounding darker and lighter distractor elements. Display composition was controlled by a genetic algorithm involving the multivariate configuration of different parameters or genes (number of distractors, element size, shape, spacing, target brightness, and distractor brightness). Sessions were composed of random displays, testing randomized combinations of these genes, and selected displays, representing the varied descendants of displays correctly identified by the pigeon. Testing a larger number of random displays than done previously, it was found that the bird’s solution to the search task was highly stable and did not change with extensive experience in the task. The location and shape of this attractor was visualized using multivariate behavioral surfaces in which element size and the number of distractors were the most important factors controlling search accuracy and search time. The resulting visualizations of the bird’s search behavior are discussed with reference to the potential of using adaptive, open-ended experimental techniques for investigating animal cognition and their implications for Bond and Kamil’s innovative development of virtual ecologies using an analogous methodology. PMID:24370702

  3. Visual Search of Food Nutrition Labels

    Microsoft Academic Search

    Joseph H. Goldberg; Claudia K. Probart; Robert E. Zak

    1999-01-01

    Using an eye-tracking methodology, we evaluated food nutrition labels' ability to support rapid and accurate visual search for nutrition information. Participants (5 practiced label readers and 5 nonreaders) viewed 180 trials of nutrition labels on a computer, finding answers to questions (e.g., serving size). Label manipulations included several alternative line arrangements, location of the question target item, and label size.

  4. Modeling Cognitive Effects on Visual Search

    E-print Network

    For Targets In; Magns Snorrason; Harald Ruda; James Hoffman

    To understand how a human operator performs visual search in complex scenes, it is necessary to take into account top-down cognitive biases in addition to bottom-up visual saliency effects. We constructed a model to elucidate the relationship between saliency and cognitive effects in the domain of visual search for distant targets in photo-realistic images of cluttered scenes. In this domain, detecting targets is difficult and requires high visual acuity. Sufficient acuity is only available near the fixation point, i.e. in the fovea. Hence, the choice of fixation points is the most important determinant of whether targets get detected. We developed a model that predicts the 2-D distribution of fixation probabilities directly from an image. Fixation probabilities were computed as a function of local contrast (saliency effect) and proximity to the horizon (cognitive effect: distant targets are more likely to be found close to the horizon). For validation, the model's predictions were compared to ensemble statistics of subjects' actual fixation locations, collected with an eye-tracker. The model's predictions correlated well with the observed data. Disabling the horizon-proximity functionality of the model significantly degraded prediction accuracy, demonstrating that cognitive effects must be accounted for when modeling visual search.

  5. On the Local Convergence of Pattern Search

    NASA Technical Reports Server (NTRS)

    Dolan, Elizabeth D.; Lewis, Robert Michael; Torczon, Virginia; Bushnell, Dennis M. (Technical Monitor)

    2000-01-01

    We examine the local convergence properties of pattern search methods, complementing the previously established global convergence properties for this class of algorithms. We show that the step-length control parameter which appears in the definition of pattern search algorithms provides a reliable asymptotic measure of first-order stationarity. This gives an analytical justification for a traditional stopping criterion for pattern search methods. Using this measure of first-order stationarity, we analyze the behavior of pattern search in the neighborhood of an isolated local minimizer. We show that a recognizable subsequence converges r-linearly to the minimizer.

  6. Pattern Search Methods for Linearly Constrained Minimization

    NASA Technical Reports Server (NTRS)

    Lewis, Robert Michael; Torczon, Virginia

    1998-01-01

    We extend pattern search methods to linearly constrained minimization. We develop a general class of feasible point pattern search algorithms and prove global convergence to a Karush-Kuhn-Tucker point. As in the case of unconstrained minimization, pattern search methods for linearly constrained problems accomplish this without explicit recourse to the gradient or the directional derivative. Key to the analysis of the algorithms is the way in which the local search patterns conform to the geometry of the boundary of the feasible region.

  7. Efficiency of Search Performance through visualizing Search Process

    Microsoft Academic Search

    Daisuke Yamashiro; T. Yoshikawa; T. Furuhashi

    2006-01-01

    Performance in searching solutions by Multi-Objective Genetic Algorithm (MOGA) depends on genetic operators and\\/or their parameters. For comparison of the performance with some genetic operators and\\/or parameters, it has been usually employed the transitions of fitness values through actual applications or the number\\/performance of acquired Pareto solutions in multi-optimization problems. This paper proposes a visualizing method of search process for

  8. Recognition of Facially Expressed Emotions and Visual Search Strategies in Adults with Asperger Syndrome

    ERIC Educational Resources Information Center

    Falkmer, Marita; Bjallmark, Anna; Larsson, Matilda; Falkmer, Torbjorn

    2011-01-01

    Can the disadvantages persons with Asperger syndrome frequently experience with reading facially expressed emotions be attributed to a different visual perception, affecting their scanning patterns? Visual search strategies, particularly regarding the importance of information from the eye area, and the ability to recognise facially expressed…

  9. Investigation of Neural Strategies of Visual Search

    NASA Technical Reports Server (NTRS)

    Krauzlis, Richard J.

    2003-01-01

    The goal of this project was to measure how neurons in the superior colliculus (SC) change their activity during a visual search task. Specifically, we proposed to measure how the activity of these neurons was altered by the discriminability of visual targets and to test how these changes might predict the changes in the subjects performance. The primary rationale for this study was that understanding how the information encoded by these neurons constrains overall search performance would foster the development of better models of human performance. Work performed during the period supported by this grant has achieved these aims. First, we have recorded from neurons in the superior colliculus (SC) during a visual search task in which the difficulty of the task and the performance of the subject was systematically varied. The results from these single-neuron physiology experiments shows that prior to eye movement onset, the difference in activity across the ensemble of neurons reaches a fixed threshold value, reflecting the operation of a winner-take-all mechanism. Second, we have developed a model of eye movement decisions based on the principle of winner-take-all . The model incorporates the idea that the overt saccade choice reflects only one of the multiple saccades prepared during visual discrimination, consistent with our physiological data. The value of the model is that, unlike previous models, it is able to account for both the latency and the percent correct of saccade choices.

  10. Visual pattern discovery in timed event data

    NASA Astrophysics Data System (ADS)

    Schaefer, Matthias; Wanner, Franz; Mansmann, Florian; Scheible, Christian; Stennett, Verity; Hasselrot, Anders T.; Keim, Daniel A.

    2011-01-01

    Business processes have tremendously changed the way large companies conduct their business: The integration of information systems into the workflows of their employees ensures a high service level and thus high customer satisfaction. One core aspect of business process engineering are events that steer the workflows and trigger internal processes. Strict requirements on interval-scaled temporal patterns, which are common in time series, are thereby released through the ordinal character of such events. It is this additional degree of freedom that opens unexplored possibilities for visualizing event data. In this paper, we present a flexible and novel system to find significant events, event clusters and event patterns. Each event is represented as a small rectangle, which is colored according to categorical, ordinal or intervalscaled metadata. Depending on the analysis task, different layout functions are used to highlight either the ordinal character of the data or temporal correlations. The system has built-in features for ordering customers or event groups according to the similarity of their event sequences, temporal gap alignment and stacking of co-occurring events. Two characteristically different case studies dealing with business process events and news articles demonstrate the capabilities of our system to explore event data.

  11. Rapid size scaling in visual search.

    PubMed

    Champion, Rebecca A; Warren, Paul A

    2008-08-01

    In order to compute a representation of an object's size within a 3D scene, the visual system must scale retinal size by an estimate of the distance to the object. Evidence from size discrimination and visual search studies suggests that we have no access to the representation of retinal size when performing such tasks. In this study we investigate whether observers have early access to retinal size prior to scene size. Observer performance was assessed in a visual search task (requiring search within a 3D scene) in which processing was interrupted at a range of short presentation times. If observers have access to retinal size then we might expect to find a presentation time before which observers behave as if using retinal size and after which they behave as if using scene size. Observers searched for a larger or smaller target object within a group of objects viewed against a textured plane slanted at 0 degrees or 60 degrees . Stimuli were presented for 100, 200, 400 or 800ms and immediately followed by a mask. We measured the effect of target location within a stimulus (near vs. far) on task performance and how this was influenced by the background slant. The results of experiments 1 and 2 suggest that background slant had a significant influence on performance at all presentation times consistent with the use of scene size and not retinal size. Experiment 3 shows that this finding cannot be explained by a 2D texture contrast effect. Experiment 4 indicates that contextual information learned across a block of trials could be an important factor in such visual search experiments. In spite of this finding, our results suggest that distance scaling may occur prior to 100ms and we find no clear evidence for explicit access to a retinal representation of size. PMID:18597808

  12. Guidance of Eye Movements During Conjunctive Visual Search: The Distractor-Ratio Effect

    Microsoft Academic Search

    Jiye Shen; Eyal M. Reingold; Marc Pomplun

    2003-01-01

    The distractor-ratio effect refers to the finding that search performance in a conjunctive visual search task depends on the relative frequency of two types or subsets of distractors when the total number of items in a display is fixed. Previously, Shen, Reingold, and Pomplun (2000) examined participants' patterns of eye movements in a distractor-ratio paradigm and demonstrated that on any

  13. Parallel Mechanisms for Visual Search in Zebrafish

    PubMed Central

    Proulx, Michael J.; Parker, Matthew O.; Tahir, Yasser; Brennan, Caroline H.

    2014-01-01

    Parallel visual search mechanisms have been reported previously only in mammals and birds, and not animals lacking an expanded telencephalon such as bees. Here we report the first evidence for parallel visual search in fish using a choice task where the fish had to find a target amongst an increasing number of distractors. Following two-choice discrimination training, zebrafish were presented with the original stimulus within an increasing array of distractor stimuli. We found that zebrafish exhibit no significant change in accuracy and approach latency as the number of distractors increased, providing evidence of parallel processing. This evidence challenges theories of vertebrate neural architecture and the importance of an expanded telencephalon for the evolution of executive function. PMID:25353168

  14. Top-down visual search in Wimmelbild

    NASA Astrophysics Data System (ADS)

    Bergbauer, Julia; Tari, Sibel

    2013-03-01

    Wimmelbild which means "teeming figure picture" is a popular genre of visual puzzles. Abundant masses of small figures are brought together in complex arrangements to make one scene in a Wimmelbild. It is picture hunt game. We discuss what type of computations/processes could possibly underlie the solution of the discovery of figures that are hidden due to a distractive influence of the context. One thing for sure is that the processes are unlikely to be purely bottom-up. One possibility is to re-arrange parts and see what happens. As this idea is linked to creativity, there are abundant examples of unconventional part re-organization in modern art. A second possibility is to define what to look for. That is to formulate the search as a top-down process. We address top-down visual search in Wimmelbild with the help of diffuse distance and curvature coding fields.

  15. Visual search from lab to clinic and back

    NASA Astrophysics Data System (ADS)

    Wolfe, Jeremy M.

    2014-03-01

    Many of the tasks of medical image perception can be understood as demanding visual search tasks (especially if you happen to be a visual search researcher). Basic research on visual search can tell us quite a lot about how medical image search tasks proceed because even experts have to use the human "search engine" with all its limitations. Humans can only deploy attention to one or a very few items at any one time. Human search is "guided" search. Humans deploy their attention to likely target objects on the basis of the basic visual features of object and on the basis of an understanding of the scene containing those objects. This guidance operates in medical images as well as in the mundane scenes of everyday life. The paper reviews some of the dialogue between medical image perception by experts and visual search as studied in the laboratory.

  16. Guided Text Search Using Adaptive Visual Analytics

    SciTech Connect

    Steed, Chad A [ORNL; Symons, Christopher T [ORNL; Senter, James K [ORNL; DeNap, Frank A [ORNL

    2012-10-01

    This research demonstrates the promise of augmenting interactive visualizations with semi- supervised machine learning techniques to improve the discovery of significant associations and insights in the search and analysis of textual information. More specifically, we have developed a system called Gryffin that hosts a unique collection of techniques that facilitate individualized investigative search pertaining to an ever-changing set of analytical questions over an indexed collection of open-source documents related to critical national infrastructure. The Gryffin client hosts dynamic displays of the search results via focus+context record listings, temporal timelines, term-frequency views, and multiple coordinate views. Furthermore, as the analyst interacts with the display, the interactions are recorded and used to label the search records. These labeled records are then used to drive semi-supervised machine learning algorithms that re-rank the unlabeled search records such that potentially relevant records are moved to the top of the record listing. Gryffin is described in the context of the daily tasks encountered at the US Department of Homeland Security s Fusion Center, with whom we are collaborating in its development. The resulting system is capable of addressing the analysts information overload that can be directly attributed to the deluge of information that must be addressed in the search and investigative analysis of textual information.

  17. An active visual search interface for Medline.

    PubMed

    Xuan, Weijian; Dai, Manhong; Mirel, Barbara; Wilson, Justin; Athey, Brian; Watson, Stanley J; Meng, Fan

    2007-01-01

    Searching the Medline database is almost a daily necessity for many biomedical researchers. However, available Medline search solutions are mainly designed for the quick retrieval of a small set of most relevant documents. Because of this search model, they are not suitable for the large-scale exploration of literature and the underlying biomedical conceptual relationships, which are common tasks in the age of high throughput experimental data analysis and cross-discipline research. We try to develop a new Medline exploration approach by incorporating interactive visualization together with powerful grouping, summary, sorting and active external content retrieval functions. Our solution, PubViz, is based on the FLEX platform designed for interactive web applications and its prototype is publicly available at: http://brainarray.mbni.med.umich.edu/Brainarray/DataMining/PubViz. PMID:17951838

  18. Words, Shape, Visual Search and Visual Working Memory in 3-Year-Old Children

    ERIC Educational Resources Information Center

    Vales, Catarina; Smith, Linda B.

    2015-01-01

    Do words cue children's visual attention, and if so, what are the relevant mechanisms? Across four experiments, 3-year-old children (N = 163) were tested in visual search tasks in which targets were cued with only a visual preview versus a visual preview and a spoken name. The experiments were designed to determine whether labels facilitated…

  19. Size Scaling in Visual Pattern Recognition

    ERIC Educational Resources Information Center

    Larsen, Axel; Bundesen, Claus

    1978-01-01

    Human visual recognition on the basis of shape but regardless of size was investigated by reaction time methods. Results suggested two processes of size scaling: mental-image transformation and perceptual-scale transformation. Image transformation accounted for matching performance based on visual short-term memory, whereas scale transformation…

  20. Continuous Subgraph Pattern Search over Graph Streams

    Microsoft Academic Search

    Changliang Wang; Lei Chen

    2009-01-01

    Search over graph databases has attracted much attention recently due to its usefulness in many fields, such as the analysis of chemical compounds, intrusion detection in network traffic data, and pattern matching over users' visiting logs. However, most of the existing work focuses on search over static graph databases while in many real applications graphs are changing over time. In

  1. Meaning Metaphor for Visualizing Search Results Nicolas Bonnel

    E-print Network

    Paris-Sud XI, Université de

    difficult to extract the relevant information for a given search. The search en- gines, which are a way interface enabling him to quickly find the relevant information. The context of our work is web search, soMeaning Metaphor for Visualizing Search Results Nicolas Bonnel France Telecom, Division R&D 4 rue

  2. Periodic-Pattern-selective Cells in Monkey Visual Cortex

    Microsoft Academic Search

    Riidiger von der Heydt; Esther Peterhans

    1992-01-01

    To study the visual processing of periodic and aperiodic patterns, we have analyzed neuronal responses in areas Vl and V2 of the visual cortex of alert monkeys during behav- iorally induced fixation of gaze. Receptive field eccentrici- ties ranged between 0.5\\

  3. Visual Pattern Recognition in Drosophila Is Invariant for

    E-print Network

    Field, David

    of their visual field where they had originally seen them. Tethered flies (Drosophila melanogaster) in a flight before. In the flight simulator (Fig. 1A), the fly's (Drosophila melanogaster) head and thorax and, henceVisual Pattern Recognition in Drosophila Is Invariant for Retinal Position Shiming Tang,1

  4. Supporting the Process of Exploring and Interpreting Space–Time Multivariate Patterns: The Visual Inquiry Toolkit

    PubMed Central

    Chen, Jin; MacEachren, Alan M.; Guo, Diansheng

    2009-01-01

    While many data sets carry geographic and temporal references, our ability to analyze these datasets lags behind our ability to collect them because of the challenges posed by both data complexity and tool scalability issues. This study develops a visual analytics approach that leverages human expertise with visual, computational, and cartographic methods to support the application of visual analytics to relatively large spatio-temporal, multivariate data sets. We develop and apply a variety of methods for data clustering, pattern searching, information visualization, and synthesis. By combining both human and machine strengths, this approach has a better chance to discover novel, relevant, and potentially useful information that is difficult to detect by any of the methods used in isolation. We demonstrate the effectiveness of the approach by applying the Visual Inquiry Toolkit we developed to analyze a data set containing geographically referenced, time-varying and multivariate data for U.S. technology industries. PMID:19960096

  5. Pattern Matching, Searching, and Heuristics in Algebra.

    ERIC Educational Resources Information Center

    Lopez, Antonio M.

    1996-01-01

    Presents a methodology designed to strengthen the cognitive effects of using graphing calculators to solve polynomial equations using pattern matching, searching, and heuristics. Discusses pattern matching as a problem-solving strategy useful in the physical, social, political, and economic worlds of today's students. (DDR)

  6. Eye Movements Reveal How Task Difficulty Moulds Visual Search

    ERIC Educational Resources Information Center

    Young, Angela H.; Hulleman, Johan

    2013-01-01

    In two experiments we investigated the relationship between eye movements and performance in visual search tasks of varying difficulty. Experiment 1 provided evidence that a single process is used for search among static and moving items. Moreover, we estimated the functional visual field (FVF) from the gaze coordinates and found that its size…

  7. Spatial Constraints on Learning in Visual Search: Modeling Contextual Cuing

    ERIC Educational Resources Information Center

    Brady, Timothy F.; Chun, Marvin M.

    2007-01-01

    Predictive visual context facilitates visual search, a benefit termed contextual cuing (M. M. Chun & Y. Jiang, 1998). In the original task, search arrays were repeated across blocks such that the spatial configuration (context) of all of the distractors in a display predicted an embedded target location. The authors modeled existing results using…

  8. Fusing Concept Detection and Geo Context for Visual Search

    E-print Network

    Smeulders, Arnold

    Fusing Concept Detection and Geo Context for Visual Search Xirong Li Cees G.M. Snoek Marcel Worring.nl,m.worring@uva.nl,arnold.smeulders@cwi.nl ABSTRACT Given the proliferation of geo-tagged images, the question of how to exploit geo tags and the underlying geo context for visual search is emerging. Based on the observation that the importance of geo

  9. Global Statistical Learning in a Visual Search Task

    ERIC Educational Resources Information Center

    Jones, John L.; Kaschak, Michael P.

    2012-01-01

    Locating a target in a visual search task is facilitated when the target location is repeated on successive trials. Global statistical properties also influence visual search, but have often been confounded with local regularities (i.e., target location repetition). In two experiments, target locations were not repeated for four successive trials,…

  10. Spatial Constraints on Learning in Visual Search: Modeling Contextual Cuing

    Microsoft Academic Search

    Timothy F. Brady; Marvin M. Chun

    2007-01-01

    Predictive visual context facilitates visual search, a benefit termed contextual cuing (M. M. Chun & Y. Jiang, 1998). In the original task, search arrays were repeated across blocks such that the spatial configuration (context) of all of the distractors in a display predicted an embedded target location. The authors modeled existing results using a connectionist architecture and then designed new

  11. Visual pattern recognition based on spatio-temporal patterns of retinal ganglion cells' activities.

    PubMed

    Jing, Wei; Liu, Wen-Zhong; Gong, Xin-Wei; Gong, Hai-Qing; Liang, Pei-Ji

    2010-09-01

    Neural information is processed based on integrated activities of relevant neurons. Concerted population activity is one of the important ways for retinal ganglion cells to efficiently organize and process visual information. In the present study, the spike activities of bullfrog retinal ganglion cells in response to three different visual patterns (checker-board, vertical gratings and horizontal gratings) were recorded using multi-electrode arrays. A measurement of subsequence distribution discrepancy (MSDD) was applied to identify the spatio-temporal patterns of retinal ganglion cells' activities in response to different stimulation patterns. The results show that the population activity patterns were different in response to different stimulation patterns, such difference in activity pattern was consistently detectable even when visual adaptation occurred during repeated experimental trials. Therefore, the stimulus pattern can be reliably discriminated according to the spatio-temporal pattern of the neuronal activities calculated using the MSDD algorithm. PMID:21886670

  12. Visual pattern recognition based on spatio-temporal patterns of retinal ganglion cells’ activities

    PubMed Central

    Jing, Wei; Liu, Wen-Zhong; Gong, Xin-Wei; Gong, Hai-Qing

    2010-01-01

    Neural information is processed based on integrated activities of relevant neurons. Concerted population activity is one of the important ways for retinal ganglion cells to efficiently organize and process visual information. In the present study, the spike activities of bullfrog retinal ganglion cells in response to three different visual patterns (checker-board, vertical gratings and horizontal gratings) were recorded using multi-electrode arrays. A measurement of subsequence distribution discrepancy (MSDD) was applied to identify the spatio-temporal patterns of retinal ganglion cells’ activities in response to different stimulation patterns. The results show that the population activity patterns were different in response to different stimulation patterns, such difference in activity pattern was consistently detectable even when visual adaptation occurred during repeated experimental trials. Therefore, the stimulus pattern can be reliably discriminated according to the spatio-temporal pattern of the neuronal activities calculated using the MSDD algorithm. PMID:21886670

  13. Visualizing non-functional requirements patterns

    Microsoft Academic Search

    Sam Supakkul; Lawrence Chung

    2010-01-01

    Properly dealing with non-functional requirements (NFRs), such as security and trustworthiness, requires a large body of knowledge about NFRs. Such knowledge can be captured as NFR patterns for reuse. Since knowledge of NFRs can have potentially complex structures and rules, it becomes hard to capture and reuse NFR patterns when they are represented only textually. In this paper, we present

  14. Modeling and visualization of leaf venation patterns

    Microsoft Academic Search

    Adam Runions; Martin Fuhrer; Pavol Federl; Anne-Gaëlle Rolland-Lagan; Przemyslaw Prusinkiewicz

    2005-01-01

    We introduce a class of biologically-motivated algorithms for generating leaf venation patterns. These algorithms simulate the interplay between three processes: (1) development of veins towards hormone (auxin) sources embedded in the leaf blade; (2) modification of the hormone source distribution by the proximity of veins; and (3) modification of both the vein pattern and source distribution by leaf growth. These

  15. Visualizing Predictability of File Access Patterns

    Microsoft Academic Search

    Alison Luo; Ahmed Amer; Newton Der; Darrell D. E. Long; Alex Pang

    We propose a novel method to study storage system pre- dictability based on the visualization of file successor en- tropy, a form of conditional entropy drawn from a file ac- cess trace. First-order conditional entropy is used as a measure of predictability. It is superior to the more com- mon measures such as independent likelihood of data ac- cess. For

  16. Spontaneous pattern formation in primary visual cortex

    E-print Network

    Bressloff, Paul C

    Figure 1.1. The visual pathway a particular local orientation [33]. Cells also show a left/right eye prefer- ence known as ocular dominance and some are also direction selective. The latter is illustrated complete picture of the two­dimensional distribution1 of both orientation preference and ocular dominance

  17. Visual search in a forced-choice paradigm

    Microsoft Academic Search

    John E. Holmgren

    1974-01-01

    The processing of visual information was investigated in the context of two visual search tasks. The first was a forced-choice\\u000a task in which one of two alternative letters appeared in a visual display of from one to five letters. The second task included\\u000a trials on which neither of the two alternatives was present in the display. Search rates were estimated

  18. Decoding complex flow-field patterns in visual working memory.

    PubMed

    Christophel, Thomas B; Haynes, John-Dylan

    2014-05-01

    There has been a long history of research on visual working memory. Whereas early studies have focused on the role of lateral prefrontal cortex in the storage of sensory information, this has been challenged by research in humans that has directly assessed the encoding of perceptual contents, pointing towards a role of visual and parietal regions during storage. In a previous study we used pattern classification to investigate the storage of complex visual color patterns across delay periods. This revealed coding of such contents in early visual and parietal brain regions. Here we aim to investigate whether the involvement of visual and parietal cortex is also observable for other types of complex, visuo-spatial pattern stimuli. Specifically, we used a combination of fMRI and multivariate classification to investigate the retention of complex flow-field stimuli defined by the spatial patterning of motion trajectories of random dots. Subjects were trained to memorize the precise spatial layout of these stimuli and to retain this information during an extended delay. We used a multivariate decoding approach to identify brain regions where spatial patterns of activity encoded the memorized stimuli. Content-specific memory signals were observable in motion sensitive visual area MT+ and in posterior parietal cortex that might encode spatial information in a modality independent manner. Interestingly, we also found information about the memorized visual stimulus in somatosensory cortex, suggesting a potential crossmodal contribution to memory. Our findings thus indicate that working memory storage of visual percepts might be distributed across unimodal, multimodal and even crossmodal brain regions. PMID:24480302

  19. BIDDING PATTERNS IN SEARCH ENGINE AUCTIONS

    Microsoft Academic Search

    KURSAD ASDEMIR

    2006-01-01

    This study analyzes how advertisers bid for search phrases in pay-per-click search engine auctions. These auctions are fundamentally different than traditional auctions in that they have no closing times and they are continuous. We develop an infinite horizon alternative-move game of advertiser bidding behavior. We show that bidding war cycle and static bid patterns frequently observed in these auctions can

  20. Online Multiple Kernel Similarity Learning for Visual Search.

    PubMed

    Xia, Hao; Hoi, Steven C H; Jin, Rong; Zhao, Peilin

    2013-08-13

    Recent years have witnessed a number of studies on distance metric learning to improve visual similarity search in Content-Based Image Retrieval (CBIR). Despite their popularity and success, most existing methods on distance metric learning are limited in two aspects. First, they typically assume the target proximity function follows the family of Mahalanobis distances, which limits their capacity of measuring similarity of complex patterns in real applications. Second, they often cannot effectively handle the similarity measure of multi-modal data that may originate from multiple resources. To overcome these limitations, this paper investigates an online kernel ranking framework for learning kernel-based proximity functions, which goes beyond the conventional linear distance metric learning approaches. Based on the framework, we propose a novel Online Multiple Kernel Ranking (OMKR) method, which learns a flexible nonlinear proximity function with multiple kernels to improve visual similarity search in CBIR. We evaluate the proposed technique for CBIR on a variety of image data sets, in which encouraging results show that OMKR outperforms the state-of-the-art techniques significantly. PMID:23959603

  1. Online multiple kernel similarity learning for visual search.

    PubMed

    Xia, Hao; Hoi, Steven C H; Jin, Rong; Zhao, Peilin

    2014-03-01

    Recent years have witnessed a number of studies on distance metric learning to improve visual similarity search in content-based image retrieval (CBIR). Despite their successes, most existing methods on distance metric learning are limited in two aspects. First, they usually assume the target proximity function follows the family of Mahalanobis distances, which limits their capacity of measuring similarity of complex patterns in real applications. Second, they often cannot effectively handle the similarity measure of multimodal data that may originate from multiple resources. To overcome these limitations, this paper investigates an online kernel similarity learning framework for learning kernel-based proximity functions which goes beyond the conventional linear distance metric learning approaches. Based on the framework, we propose a novel online multiple kernel similarity (OMKS) learning method which learns a flexible nonlinear proximity function with multiple kernels to improve visual similarity search in CBIR. We evaluate the proposed technique for CBIR on a variety of image data sets in which encouraging results show that OMKS outperforms the state-of-the-art techniques significantly. PMID:24457509

  2. Preattentive Segmentation of Objects from Backgrounds in Visual Search

    E-print Network

    experience) shows that observers can search through a relevant set of objects (e.g. all of the carsPreattentive Segmentation of Objects from Backgrounds in Visual Search Aude Oliva, Serena J Butcher & Jeremy M Wolfe Harvard Medical School & Brigham and Women's Hospital, Boston. Email: {oliva,serena,wolfe}@search

  3. EFFECTIVE ORGANIZATION AND VISUALIZATION OF WEB SEARCH Nicolas Bonnel

    E-print Network

    Boyer, Edmond

    the relevant information for a given search since available data on the World Wide Web is con- stantly of the presented approach, which is to offer the user a search interface enabling him to quickly find the relevantEFFECTIVE ORGANIZATION AND VISUALIZATION OF WEB SEARCH RESULTS Nicolas Bonnel IRISA Rennes, France

  4. Visual search behaviour during laparoscopic cadaveric procedures

    NASA Astrophysics Data System (ADS)

    Dong, Leng; Chen, Yan; Gale, Alastair G.; Rees, Benjamin; Maxwell-Armstrong, Charles

    2014-03-01

    Laparoscopic surgery provides a very complex example of medical image interpretation. The task entails: visually examining a display that portrays the laparoscopic procedure from a varying viewpoint; eye-hand coordination; complex 3D interpretation of the 2D display imagery; efficient and safe usage of appropriate surgical tools, as well as other factors. Training in laparoscopic surgery typically entails practice using surgical simulators. Another approach is to use cadavers. Viewing previously recorded laparoscopic operations is also a viable additional approach and to examine this a study was undertaken to determine what differences exist between where surgeons look during actual operations and where they look when simply viewing the same pre-recorded operations. It was hypothesised that there would be differences related to the different experimental conditions; however the relative nature of such differences was unknown. The visual search behaviour of two experienced surgeons was recorded as they performed three types of laparoscopic operations on a cadaver. The operations were also digitally recorded. Subsequently they viewed the recording of their operations, again whilst their eye movements were monitored. Differences were found in various eye movement parameters when the two surgeons performed the operations and where they looked when they simply watched the recordings of the operations. It is argued that this reflects the different perceptual motor skills pertinent to the different situations. The relevance of this for surgical training is explored.

  5. Image pattern recognition supporting interactive analysis and graphical visualization

    NASA Technical Reports Server (NTRS)

    Coggins, James M.

    1992-01-01

    Image Pattern Recognition attempts to infer properties of the world from image data. Such capabilities are crucial for making measurements from satellite or telescope images related to Earth and space science problems. Such measurements can be the required product itself, or the measurements can be used as input to a computer graphics system for visualization purposes. At present, the field of image pattern recognition lacks a unified scientific structure for developing and evaluating image pattern recognition applications. The overall goal of this project is to begin developing such a structure. This report summarizes results of a 3-year research effort in image pattern recognition addressing the following three principal aims: (1) to create a software foundation for the research and identify image pattern recognition problems in Earth and space science; (2) to develop image measurement operations based on Artificial Visual Systems; and (3) to develop multiscale image descriptions for use in interactive image analysis.

  6. Reinforcing saccadic amplitude variability in a visual search task.

    PubMed

    Paeye, Céline; Madelain, Laurent

    2014-01-01

    Human observers often adopt rigid scanning strategies in visual search tasks, even though this may lead to suboptimal performance. Here we ask whether specific levels of saccadic amplitude variability may be induced in a visual search task using reinforcement learning. We designed a new gaze-contingent visual foraging task in which finding a target among distractors was made contingent upon specific saccadic amplitudes. When saccades of rare amplitudes led to displaying the target, the U values (measuring uncertainty) increased by 54.89% on average. They decreased by 41.21% when reinforcing frequent amplitudes. In a noncontingent control group no consistent change in variability occurred. A second experiment revealed that this learning transferred to conventional visual search trials. These results provide experimental support for the importance of reinforcement learning for saccadic amplitude variability in visual search. PMID:25413626

  7. Visual search in a forced-choice paradigm

    NASA Technical Reports Server (NTRS)

    Holmgren, J. E.

    1974-01-01

    The processing of visual information was investigated in the context of two visual search tasks. The first was a forced-choice task in which one of two alternative letters appeared in a visual display of from one to five letters. The second task included trials on which neither of the two alternatives was present in the display. Search rates were estimated from the slopes of best linear fits to response latencies plotted as a function of the number of items in the visual display. These rates were found to be much slower than those estimated in yes-no search tasks. This result was interpreted as indicating that the processes underlying visual search in yes-no and forced-choice tasks are not the same.

  8. Sequential pattern data mining and visualization

    DOEpatents

    Wong, Pak Chung (Richland, WA); Jurrus, Elizabeth R. (Kennewick, WA); Cowley, Wendy E. (Benton City, WA); Foote, Harlan P. (Richland, WA); Thomas, James J. (Richland, WA)

    2011-12-06

    One or more processors (22) are operated to extract a number of different event identifiers therefrom. These processors (22) are further operable to determine a number a display locations each representative of one of the different identifiers and a corresponding time. The display locations are grouped into sets each corresponding to a different one of several event sequences (330a, 330b, 330c. 330d, 330e). An output is generated corresponding to a visualization (320) of the event sequences (330a, 330b, 330c, 330d, 330e).

  9. Sequential pattern data mining and visualization

    DOEpatents

    Wong, Pak Chung (Richland, WA); Jurrus, Elizabeth R. (Kennewick, WA); Cowley, Wendy E. (Benton City, WA); Foote, Harlan P. (Richland, WA); Thomas, James J. (Richland, WA)

    2009-05-26

    One or more processors (22) are operated to extract a number of different event identifiers therefrom. These processors (22) are further operable to determine a number a display locations each representative of one of the different identifiers and a corresponding time. The display locations are grouped into sets each corresponding to a different one of several event sequences (330a, 330b, 330c. 330d, 330e). An output is generated corresponding to a visualization (320) of the event sequences (330a, 330b, 330c, 330d, 330e).

  10. Searching for intellectual turning points: Progressive knowledge domain visualization

    PubMed Central

    Chen, Chaomei

    2004-01-01

    This article introduces a previously undescribed method progressively visualizing the evolution of a knowledge domain's cocitation network. The method first derives a sequence of cocitation networks from a series of equal-length time interval slices. These time-registered networks are merged and visualized in a panoramic view in such a way that intellectually significant articles can be identified based on their visually salient features. The method is applied to a cocitation study of the superstring field in theoretical physics. The study focuses on the search of articles that triggered two superstring revolutions. Visually salient nodes in the panoramic view are identified, and the nature of their intellectual contributions is validated by leading scientists in the field. The analysis has demonstrated that a search for intellectual turning points can be narrowed down to visually salient nodes in the visualized network. The method provides a promising way to simplify otherwise cognitively demanding tasks to a search for landmarks, pivots, and hubs. PMID:14724295

  11. DTN routing strategies using optimal search patterns

    Microsoft Academic Search

    Minsu Shin; Seongik Hong; Injong Rhee

    2008-01-01

    ABSTRACT Biologists have long shown,that the mobility patterns of many foraging animals and insects are similar to Levy walks and Levy walks are an optimal search strategy when,tar- get objects (i.e., food sources) are sparse and their locations are not known in advance. In this paper, we apply Levy walk patterns to routing in delay tolerant networks (DTN). In DTNs,

  12. Artificial retinal neural network for visual pattern recognition

    NASA Astrophysics Data System (ADS)

    Guo, Donghui; Cheng, Lee Ming; Cheng, L. L.; Chen, Zhenxiang; Liu, Ruitang; Wu, Boxi

    1996-03-01

    With feed-forward adaptive network (FFAN) and feed-back associative network (FBAN) respectively imitating the performances of retina and cerebral cortex, an artificial retinal neural network (ARNN) was presented in this paper for fast recognition of visual patterns. In our ARNN model to be implemented with neural network chip MD1200, every synaption of neurons can be arbitrarily given as an integer value from minus 215 to 215. After these synaptions are trained, the visual pattern not only under geometric transformation but also in the presence of noise can be recognized by the ARNN's system.

  13. Simple drawing and pattern completion techniques for studying visualization and long-term visual knowledge

    Microsoft Academic Search

    D. F. M. Christie; W. A. Phillips

    1979-01-01

    Simple and efficient drawing and completion tasks for studying visual memory are developed. In Experiment I subjects reproduced\\u000a a series of matrix patterns by filling empty matrices. The serial position function was fiat, except that accuracy was much\\u000a higher for final patterns. In Experiment 2 this recency effect was removed by an interpolated pattern classification task.\\u000a Experiments 3 and 4

  14. Hierarchical visual event pattern mining and its applications

    Microsoft Academic Search

    Peng Cui; Zhi-Qiang Liu; Li-Feng Sun; Shi-Qiang Yang

    2011-01-01

    In this paper, we propose a hierarchical visual event pattern mining approach and utilize the patterns to address the key\\u000a problems in video mining and understanding field. We classify events into primitive events (PEs) and compound events (CEs),\\u000a where PEs are the units of CEs, and CEs serve as smooth priors and rules for PEs. We first propose a tensor-based

  15. Recognizing patterns of visual field loss using unsupervised machine learning

    NASA Astrophysics Data System (ADS)

    Yousefi, Siamak; Goldbaum, Michael H.; Zangwill, Linda M.; Medeiros, Felipe A.; Bowd, Christopher

    2014-03-01

    Glaucoma is a potentially blinding optic neuropathy that results in a decrease in visual sensitivity. Visual field abnormalities (decreased visual sensitivity on psychophysical tests) are the primary means of glaucoma diagnosis. One form of visual field testing is Frequency Doubling Technology (FDT) that tests sensitivity at 52 points within the visual field. Like other psychophysical tests used in clinical practice, FDT results yield specific patterns of defect indicative of the disease. We used Gaussian Mixture Model with Expectation Maximization (GEM), (EM is used to estimate the model parameters) to automatically separate FDT data into clusters of normal and abnormal eyes. Principal component analysis (PCA) was used to decompose each cluster into different axes (patterns). FDT measurements were obtained from 1,190 eyes with normal FDT results and 786 eyes with abnormal (i.e., glaucomatous) FDT results, recruited from a university-based, longitudinal, multi-center, clinical study on glaucoma. The GEM input was the 52-point FDT threshold sensitivities for all eyes. The optimal GEM model separated the FDT fields into 3 clusters. Cluster 1 contained 94% normal fields (94% specificity) and clusters 2 and 3 combined, contained 77% abnormal fields (77% sensitivity). For clusters 1, 2 and 3 the optimal number of PCA-identified axes were 2, 2 and 5, respectively. GEM with PCA successfully separated FDT fields from healthy and glaucoma eyes and identified familiar glaucomatous patterns of loss.

  16. Rapid compensation of visual search strategy in patients with chronic visual field defects

    PubMed Central

    Jacquin-Courtois, Sophie; Bays, Paul M.; Salemme, Romeo; Leff, Alexander P.; Husain, Masud

    2014-01-01

    Introduction The aim of this study was to test the effect and specificity of a novel, compensatory eye movement training therapy designed to improve visual search performance in patients with homonymous visual field defects. Methods Seven patients with chronic homonymous visual field defects and six healthy control subjects were tested. All subjects completed the single training period (300 trials). Subjects were assessed on three different saccadic tasks (a visual search task, a rapid scanning task and a reading task) which were evaluated at three time points on the same day: two before and one after the training period. The computer-based training consisted of a novel ramp-step search paradigm that required subjects to pursue a stimulus (ramp phase) and then saccade to find its location when it suddenly jumped (step phase). Results Pre-therapy we confirmed that patients differed from controls on the visual search task. Post-training we demonstrated a clear improvement in terms of reaction time required to complete the visual search. This effect was confined to: (1) the patient group only; (2) targets presented to the blind visual field of the patients only; (3) the visual search task only and not the rapid scanning or reading task. Conclusion These results demonstrate that rapid, compensatory changes can occur in patients with visual field defects that impact on their ability to carry out efficient visual search. We plan to translate this therapy, along with appropriate testing materials, in a free-to-use, internet-based application based on this intervention. PMID:22626007

  17. Fatigue and Structural Change: Two Consequences of Visual Pattern Adaptation

    E-print Network

    Fatigue and Structural Change: Two Consequences of Visual Pattern Adaptation Jeremy M. Wolfe-term fatigue, produced very quickly and (2) long-term structural change, requiring more extended adaptation reductions in the sensitivity of the mechanisms detecting the stimulus. Adaptation fatigues the mechanism

  18. Visual Search in a Multi-Element Asynchronous Dynamic (MAD) World

    ERIC Educational Resources Information Center

    Kunar, Melina A.; Watson, Derrick G.

    2011-01-01

    In visual search tasks participants search for a target among distractors in strictly controlled displays. We show that visual search principles observed in these tasks do not necessarily apply in more ecologically valid search conditions, using dynamic and complex displays. A multi-element asynchronous dynamic (MAD) visual search was developed in…

  19. Pre-exposure of repeated search configurations facilitates subsequent contextual cuing of visual search.

    PubMed

    Beesley, Tom; Vadillo, Miguel A; Pearson, Daniel; Shanks, David R

    2015-03-01

    Contextual cuing is the enhancement of visual search when the configuration of distractors has been experienced previously. It has been suggested that contextual cuing relies on associative learning between the distractor locations and the target position. Four experiments examined the effect of pre-exposing configurations of consistent distractors on subsequent contextual cuing. The findings demonstrate a facilitation of subsequent cuing for pre-exposed configurations compared to novel configurations that have not been pre-exposed. This facilitation suggests that learning of repeated visual search patterns involves acquisition of not just distractor-target associations but also associations between distractors within the search context, an effect that is not captured by the Brady and Chun (2007) connectionist model of contextual cuing. We propose a new connectionist model of contextual cuing that learns associations between repeated distractor stimuli, enabling it to predict an effect of pre-exposure on contextual cuing. (PsycINFO Database Record (c) 2015 APA, all rights reserved). PMID:24999706

  20. Algorithm 856: APPSPACK 4.0: Asynchronous Parallel Pattern Search

    E-print Network

    Kolda, Tamara G.

    Algorithm 856: APPSPACK 4.0: Asynchronous Parallel Pattern Search for Derivative-Free Optimization unconstrained and bound-constrained optimization problems. It implements an asynchronous parallel pattern search-free optimization, pattern search 1. INTRODUCTION APPSPACK is software for solving unconstrained and bound

  1. ON THE CONVERGENCE OF ASYNCHRONOUS PARALLEL PATTERN SEARCH

    E-print Network

    Kolda, Tamara G.

    ON THE CONVERGENCE OF ASYNCHRONOUS PARALLEL PATTERN SEARCH TAMARA G. KOLDA AND VIRGINIA J. TORCZON­964 Abstract. In this paper we prove global convergence for asynchronous parallel pattern search. In standard pattern search, decisions regarding the update of the iterate and the step-length control parameter

  2. Functional MRI mapping of visual function and selective attention for performance assessment and presurgical planning using conjunctive visual search

    PubMed Central

    Parker, Jason G; Zalusky, Eric J; Kirbas, Cemil

    2014-01-01

    Background Accurate mapping of visual function and selective attention using fMRI is important in the study of human performance as well as in presurgical treatment planning of lesions in or near visual centers of the brain. Conjunctive visual search (CVS) is a useful tool for mapping visual function during fMRI because of its greater activation extent compared with high-capacity parallel search processes. Aims The purpose of this work was to develop and evaluate a CVS that was capable of generating consistent activation in the basic and higher level visual areas of the brain by using a high number of distractors as well as an optimized contrast condition. Materials and methods Images from 10 healthy volunteers were analyzed and brain regions of greatest activation and deactivation were determined using a nonbiased decomposition of the results at the hemisphere, lobe, and gyrus levels. The results were quantified in terms of activation and deactivation extent and mean z-statistic. Results The proposed CVS was found to generate robust activation of the occipital lobe, as well as regions in the middle frontal gyrus associated with coordinating eye movements and in regions of the insula associated with task-level control and focal attention. As expected, the task demonstrated deactivation patterns commonly implicated in the default-mode network. Further deactivation was noted in the posterior region of the cerebellum, most likely associated with the formation of optimal search strategy. Conclusion We believe the task will be useful in studies of visual and selective attention in the neuroscience community as well as in mapping visual function in clinical fMRI. PMID:24683515

  3. Visual search, anticipation and expertise in soccer goalkeepers

    Microsoft Academic Search

    Geert J. P. Savelsbergh; A. Mark Williams; John Van Der Kamp; Paul Ward

    2002-01-01

    We used a novel methodological approach to examine skill-based differences in anticipation and visual search behaviour during the penalty kick in soccer. Expert and novice goalkeepers were required to move a joystick in response to penalty kicks presented on film. The proportion of penalties saved was assessed, as well as the frequency and time of initiation of joystick corrections. Visual

  4. Visual processing of contour patterns under conditions of inattentional blindness.

    PubMed

    Pitts, Michael A; Martínez, Antígona; Hillyard, Steven A

    2012-02-01

    An inattentional blindness paradigm was adapted to measure ERPs elicited by visual contour patterns that were or were not consciously perceived. In the first phase of the experiment, subjects performed an attentionally demanding task while task-irrelevant line segments formed square-shaped patterns or random configurations. After the square patterns had been presented 240 times, subjects' awareness of these patterns was assessed. More than half of all subjects, when queried, failed to notice the square patterns and were thus considered inattentionally blind during this first phase. In the second phase of the experiment, the task and stimuli were the same, but following this phase, all of the subjects reported having seen the patterns. ERPs recorded over the occipital pole differed in amplitude from 220 to 260 msec for the pattern stimuli compared with the random arrays regardless of whether subjects were aware of the patterns. At subsequent latencies (300-340 msec) however, ERPs over bilateral occipital-parietal areas differed between patterns and random arrays only when subjects were aware of the patterns. Finally, in a third phase of the experiment, subjects viewed the same stimuli, but the task was altered so that the patterns became task relevant. Here, the same two difference components were evident but were followed by a series of additional components that were absent in the first two phases of the experiment. We hypothesize that the ERP difference at 220-260 msec reflects neural activity associated with automatic contour integration whereas the difference at 300-340 msec reflects visual awareness, both of which are dissociable from task-related postperceptual processing. PMID:21812561

  5. Changing perspective: zooming in and out during visual search.

    PubMed

    Solman, Grayden J F; Cheyne, J Allan; Smilek, Daniel

    2013-04-01

    Laboratory studies of visual search are generally conducted in contexts with a static observer vantage point, constrained by a fixation cross or a headrest. In contrast, in many naturalistic search settings, observers freely adjust their vantage point by physically moving through space. In two experiments, we evaluate behavior during free vantage point (FVP) search, using observer-controlled zooming to simulate movement toward or away from search objects. We focus on scope fluctuations--repeated reversals in the direction of zooming during search. We found increased fluctuation when search items were sparse (Experiment 1) or of mixed size (Experiment 2). We propose that during FVP search, observers attempt to maximize the number of simultaneously discriminable items. Scope fluctuations emerge when maximizing does not enable simultaneous access to all search items, or when observers become disoriented in the search environment, necessitating repeated switches to a broad scope to reorient. PMID:22889185

  6. Bottom-Up Guidance in Visual Search for Conjunctions

    ERIC Educational Resources Information Center

    Proulx, Michael J.

    2007-01-01

    Understanding the relative role of top-down and bottom-up guidance is crucial for models of visual search. Previous studies have addressed the role of top-down and bottom-up processes in search for a conjunction of features but with inconsistent results. Here, the author used an attentional capture method to address the role of top-down and…

  7. Why Is Visual Search Superior in Autism Spectrum Disorder?

    ERIC Educational Resources Information Center

    Joseph, Robert M.; Keehn, Brandon; Connolly, Christine; Wolfe, Jeremy M.; Horowitz, Todd S.

    2009-01-01

    This study investigated the possibility that enhanced memory for rejected distractor locations underlies the superior visual search skills exhibited by individuals with autism spectrum disorder (ASD). We compared the performance of 21 children with ASD and 21 age- and IQ-matched typically developing (TD) children in a standard static search task…

  8. Behavior and neural basis of near-optimal visual search

    Microsoft Academic Search

    Vidhya Navalpakkam; Jeffrey M Beck; Ronald van den Berg; Alexandre Pouget; Wei Ji Ma

    2011-01-01

    The ability to search efficiently for a target in a cluttered environment is one of the most remarkable functions of the nervous system. This task is difficult under natural circumstances, as the reliability of sensory information can vary greatly across space and time and is typically a priori unknown to the observer. In contrast, visual-search experiments commonly use stimuli of

  9. Changing Perspective: Zooming in and out during Visual Search

    ERIC Educational Resources Information Center

    Solman, Grayden J. F.; Cheyne, J. Allan; Smilek, Daniel

    2013-01-01

    Laboratory studies of visual search are generally conducted in contexts with a static observer vantage point, constrained by a fixation cross or a headrest. In contrast, in many naturalistic search settings, observers freely adjust their vantage point by physically moving through space. In two experiments, we evaluate behavior during free vantage…

  10. Pip and Pop: Nonspatial Auditory Signals Improve Spatial Visual Search

    ERIC Educational Resources Information Center

    Van der Burg, Erik; Olivers, Christian N. L.; Bronkhorst, Adelbert W.; Theeuwes, Jan

    2008-01-01

    Searching for an object within a cluttered, continuously changing environment can be a very time-consuming process. The authors show that a simple auditory pip drastically decreases search times for a synchronized visual object that is normally very difficult to find. This effect occurs even though the pip contains no information on the location…

  11. Visual Search and Dual Tasks Reveal Two Distinct Attentional Resources

    E-print Network

    Koch, Christof

    with respect to dual-task performance. We provide examples of targets that do not trigger pop-out even though they can be discrimi- nated from distractors in dual-task situations, and of targets that can be searchedVisual Search and Dual Tasks Reveal Two Distinct Attentional Resources Rufin VanRullen1, *, Lavanya

  12. Asynchronous parallel pattern search for nonlinear optimization

    SciTech Connect

    P. D. Hough; T. G. Kolda; V. J. Torczon

    2000-01-01

    Parallel pattern search (PPS) can be quite useful for engineering optimization problems characterized by a small number of variables (say 10--50) and by expensive objective function evaluations such as complex simulations that take from minutes to hours to run. However, PPS, which was originally designed for execution on homogeneous and tightly-coupled parallel machine, is not well suited to the more heterogeneous, loosely-coupled, and even fault-prone parallel systems available today. Specifically, PPS is hindered by synchronization penalties and cannot recover in the event of a failure. The authors introduce a new asynchronous and fault tolerant parallel pattern search (AAPS) method and demonstrate its effectiveness on both simple test problems as well as some engineering optimization problems

  13. Running head: SACCADIC SELECTIVITY DURING VISUAL SEARCH Saccadic selectivity during visual search: The influence of central processing difficulty

    E-print Network

    Pomplun, Marc

    of Toronto 100 St. George Street Toronto, Ontario, Canada, M5S 3G3 Phone: (416) 978-3990 E-mail: reingold of central discrimination and the efficiency of peripheral selection in visual search tasks. Participants of the central discrimination by introducing a concurrent visual task (Experiment 2) and by presenting a gaze

  14. Reduced Comparison Speed during Visual Search in Late Life Depression

    PubMed Central

    Potter, Guy G.; Madden, David J.; Costello, Mathew C.; Steffens, David C.

    2013-01-01

    Slowed information processing is a prominent deficit in late-life depression (LLD). To better differentiate processing speed components in LLD, we examined characteristics of visual search performance in 32 LLD and 32 control participants. Data showed specific slowing in the comparison stage of visual search in LLD, rather than in encoding/response stages, but also greater overall slowing in LLD during inefficient versus efficient search. We found no group differences on traditional neuropsychological measures of processing speed. Slowed processing speed in LLD may be specific rather than general, which underscores the need to link components of processing speed to underlying neural circuitry. PMID:24219302

  15. Reward-Priming of Location in Visual Search

    PubMed Central

    Hickey, Clayton; Chelazzi, Leonardo; Theeuwes, Jan

    2014-01-01

    Existing visual search research has demonstrated that the receipt of reward will be beneficial for subsequent perceptual and attentional processing of features that have characterized targets, but detrimental for processing of features that have characterized irrelevant distractors. Here we report a similar effect of reward on location. Observers completed a visual search task in which they selected a target, ignored a salient distractor, and received random-magnitude reward for correct performance. Results show that when target selection garnered rewarding outcome attention is subsequently a.) primed to return to the target location, and b.) biased away from the location that was occupied by the salient, task-irrelevant distractor. These results suggest that in addition to priming features, reward acts to guide visual search by priming contextual locations of visual stimuli. PMID:25080218

  16. Appears in ASIST 2004, November 13-18, 2004, Providence, RI, USA. Visual Search Editor for Composing Meta Searches

    E-print Network

    Spoerri, Anselm

    can visually combine the top results retrieved by different search engines to create crystals results returned by different search engines. Users can apply different weights to the search engines fusion of different search engine results by enabling user to visually compose and refine meta searches

  17. A Visualization System for Web Local Search

    Microsoft Academic Search

    Michele Angelaccio; Berta Buttarazzi

    2000-01-01

    World Wide Web visualisation systems are widely used for browsing or viewing search engine results. In the case of a local Web search tool, however, the browsing paradigm is combined with a searching paradigm, thus requiring dynamic visualisation methods. We describe an example of a visualisation system that is an extension of a common JavaScript script that is used as

  18. Pattern Visual Evoked Potentials Elicited by Organic Electroluminescence Screen

    PubMed Central

    Matsumoto, Celso Soiti; Shinoda, Kei; Matsumoto, Harue; Funada, Hideaki; Minoda, Haruka

    2014-01-01

    Purpose. To determine whether organic electroluminescence (OLED) screens can be used as visual stimulators to elicit pattern-reversal visual evoked potentials (p-VEPs). Method. Checkerboard patterns were generated on a conventional cathode-ray tube (S710, Compaq Computer Co., USA) screen and on an OLED (17 inches, 320 × 230?mm, PVM-1741, Sony, Tokyo, Japan) screen. The time course of the luminance changes of each monitor was measured with a photodiode. The p-VEPs elicited by these two screens were recorded from 15 eyes of 9 healthy volunteers (22.0 ± 0.8 years). Results. The OLED screen had a constant time delay from the onset of the trigger signal to the start of the luminescence change. The delay during the reversal phase from black to white for the pattern was 1.0?msec on the cathode-ray tube (CRT) screen and 0.5?msec on the OLED screen. No significant differences in the amplitudes of P100 and the implicit times of N75 and P100 were observed in the p-VEPs elicited by the CRT and the OLED screens. Conclusion. The OLED screen can be used as a visual stimulator to elicit p-VEPs; however the time delay and the specific properties in the luminance change must be taken into account. PMID:25197652

  19. A Summary Statistic Representation in Peripheral Vision Explains Visual Search

    PubMed Central

    Rosenholtz, Ruth; Huang, Jie; Raj, Alvin; Balas, Benjamin J.; Ilie, Livia

    2014-01-01

    Vision is an active process: we repeatedly move our eyes to seek out objects of interest and explore our environment. Visual search experiments capture aspects of this process, by having subjects look for a target within a background of distractors. Search speed often correlates with target-distractor discriminability; search is faster when the target and distractors look quite different. However, there are notable exceptions. A given discriminability can yield efficient searches (where the target seems to “pop-out”) as well as inefficient ones (where additional distractors make search significantly slower and more difficult). Search is often more difficult when finding the target requires distinguishing a particular configuration or conjunction of features. Search asymmetries abound. These puzzling results have fueled three decades of theoretical and experimental studies. We argue that the key issue in search is the processing of image patches in the periphery, where visual representation is characterized by summary statistics computed over a sizable pooling region. By quantifying these statistics, we predict a set of classic search results, as well as peripheral discriminability of crowded patches such as those found in search displays. PMID:22523401

  20. Attention modulates visual-tactile interaction in spatial pattern matching.

    PubMed

    Göschl, Florian; Engel, Andreas K; Friese, Uwe

    2014-01-01

    Factors influencing crossmodal interactions are manifold and operate in a stimulus-driven, bottom-up fashion, as well as via top-down control. Here, we evaluate the interplay of stimulus congruence and attention in a visual-tactile task. To this end, we used a matching paradigm requiring the identification of spatial patterns that were concurrently presented visually on a computer screen and haptically to the fingertips by means of a Braille stimulator. Stimulation in our paradigm was always bimodal with only the allocation of attention being manipulated between conditions. In separate blocks of the experiment, participants were instructed to (a) focus on a single modality to detect a specific target pattern, (b) pay attention to both modalities to detect a specific target pattern, or (c) to explicitly evaluate if the patterns in both modalities were congruent or not. For visual as well as tactile targets, congruent stimulus pairs led to quicker and more accurate detection compared to incongruent stimulation. This congruence facilitation effect was more prominent under divided attention. Incongruent stimulation led to behavioral decrements under divided attention as compared to selectively attending a single sensory channel. Additionally, when participants were asked to evaluate congruence explicitly, congruent stimulation was associated with better performance than incongruent stimulation. Our results extend previous findings from audiovisual studies, showing that stimulus congruence also resulted in behavioral improvements in visuotactile pattern matching. The interplay of stimulus processing and attentional control seems to be organized in a highly flexible fashion, with the integration of signals depending on both bottom-up and top-down factors, rather than occurring in an 'all-or-nothing' manner. PMID:25203102

  1. Eye movements in iconic visual search

    Microsoft Academic Search

    Rajesh P. N. Rao; Gregory J. Zelinsky; Mary M. Hayhoe; Dana H. Ballard

    2002-01-01

    Visual cognition depends critically on the moment-to-moment orientation of gaze. To change the gaze to a new location in space, that location must be computed and used by the oculomotor system. One of the most common sources of information for this computation is the visual appearance of an object. A crucial question is: How is the appearance information contained in

  2. Spontaneous pattern formation and pinning in the visual cortex

    NASA Astrophysics Data System (ADS)

    Baker, Tanya I.

    Bifurcation theory and perturbation theory can be combined with a knowledge of the underlying circuitry of the visual cortex to produce an elegant story explaining the phenomenon of visual hallucinations. A key insight is the application of an important set of ideas concerning spontaneous pattern formation introduced by Turing in 1952. The basic mechanism is a diffusion driven linear instability favoring a particular wavelength that determines the size of the ensuing stripe or spot periodicity of the emerging spatial pattern. Competition between short range excitation and longer range inhibition in the connectivity profile of cortical neurons provides the difference in diffusion length scales necessary for the Turing mechanism to occur and has been proven by Ermentrout and Cowan to be sufficient to explain the generation of a subset of reported geometric hallucinations. Incorporating further details of the cortical circuitry, namely that neurons are also weakly connected to other neurons sharing a particular stimulus orientation or spatial frequency preference at even longer ranges and the resulting shift-twist symmetry of the neuronal connectivity, improves the story. We expand this approach in order to be able to include the tuned responses of cortical neurons to additional visual stimulus features such as motion, color and disparity. We apply a study of nonlinear dynamics similar to the analysis of wave propagation in a crystalline lattice to demonstrate how a spatial pattern formed through the Turing instability can be pinned to the geometric layout of various feature preferences. The perturbation analysis is analogous to solving the Schrodinger equation in a weak periodic potential. Competition between the local isotropic connections which produce patterns of activity via the Turing mechanism and the weaker patchy lateral connections that depend on a neuron's particular set of feature preferences create long wavelength affects analogous to commensurate-incommensurate transitions found in fluid systems under a spatially periodic driving force. In this way we hope to better understand how the intrinsic architecture of the visual cortex can generate patterns of activity that underlie visual hallucinations.

  3. Visual search and attention to faces in early infancy

    PubMed Central

    Frank, Michael C.; Amso, Dima; Johnson, Scott P.

    2013-01-01

    Newborn babies look preferentially at faces and face-like displays; yet over the course of their first year, much changes about both the way infants process visual stimuli and how they allocate their attention to the social world. Despite this initial preference for faces in restricted contexts, the amount that infants look at faces increases considerably in the first year. Is this development related to changes in attentional orienting abilities? We explored this possibility by showing 3-, 6-, and 9-month-olds engaging animated and live-action videos of social stimuli and additionally measuring their visual search performance with both moving and static search displays. Replicating previous findings, looking at faces increased with age; in addition, the amount of looking at faces was strongly related to the youngest infants’ performance in visual search. These results suggest that infants’ attentional abilities may be an important factor facilitating their social attention early in development. PMID:24211654

  4. Memory of clay paste visualized as crack pattern

    NASA Astrophysics Data System (ADS)

    Nakahara, Akio; Matsuo, Yousuke

    2010-05-01

    Clay paste can remember the direction of vibration and flow. These memories are contained as anisotrpoic network structure of clay particles inside paste. It is difficult to see directly microscopic network structure inside paste, but, when the clay paste is broken such as the case of drying process, these memories in paste can be visualized as morphology of macroscopic crack patterns [1]. We have two application of the memory effect of paste. First application is for engineering, where we can control the morphology of crack patterns by controling the memory of paste [1-2]. The other application is for the field of geoscience, because by checking the crack patterns of clay paste or clay rock observed in nature, we can estimate what happened before in the history of earth. [1] A. Nakahara and Y. Matsuo, Phys. Rev. E74 (2006) 045102. [2] Physics Today, September 2007, p. 116.

  5. Cognitive psychology: rare items often missed in visual searches.

    PubMed

    Wolfe, Jeremy M; Horowitz, Todd S; Kenner, Naomi M

    2005-05-26

    Our society relies on accurate performance in visual screening tasks--for example, to detect knives in luggage or tumours in mammograms. These are visual searches for rare targets. We show here that target rarity leads to disturbingly inaccurate performance in target detection: if observers do not find what they are looking for fairly frequently, they often fail to notice it when it does appear. PMID:15917795

  6. Advanced analysis of free visual exploration patterns in schizophrenia

    PubMed Central

    Sprenger, Andreas; Friedrich, Monique; Nagel, Matthias; Schmidt, Christiane S.; Moritz, Steffen; Lencer, Rebekka

    2013-01-01

    Background: Visual scanpath analyses provide important information about attention allocation and attention shifting during visual exploration of social situations. This study investigated whether patients with schizophrenia simply show restricted free visual exploration behavior reflected by reduced saccade frequency and increased fixation duration or whether patients use qualitatively different exploration strategies than healthy controls. Methods: Scanpaths of 32 patients with schizophrenia and age-matched 33 healthy controls were assessed while participants freely explored six photos of daily life situations (20 s/photo) evaluated for cognitive complexity and emotional strain. Using fixation and saccade parameters, we compared temporal changes in exploration behavior, cluster analyses, attentional landscapes, and analyses of scanpath similarities between both groups. Results: We found fewer fixation clusters, longer fixation durations within a cluster, fewer changes between clusters, and a greater increase of fixation duration over time in patients compared to controls. Scanpath patterns and attentional landscapes in patients also differed significantly from those of controls. Generally, cognitive complexity and emotional strain had significant effects on visual exploration behavior. This effect was similar in both groups as were physical properties of fixation locations. Conclusions: Longer attention allocation to a given feature in a scene and less attention shifts in patients suggest a more focal processing mode compared to a more ambient exploration strategy in controls. These visual exploration alterations were present in patients independently of cognitive complexity, emotional strain or physical properties of visual cues implying that they represent a rather general deficit. Despite this impairment, patients were able to adapt their scanning behavior to changes in cognitive complexity and emotional strain similar to controls. PMID:24130547

  7. Visualization of oxygen distribution patterns caused by coral and algae

    PubMed Central

    Smith, Jennifer E.; Abieri, Maria L.; Hatay, Mark; Rohwer, Forest

    2013-01-01

    Planar optodes were used to visualize oxygen distribution patterns associated with a coral reef associated green algae (Chaetomorpha sp.) and a hermatypic coral (Favia sp.) separately, as standalone organisms, and placed in close proximity mimicking coral-algal interactions. Oxygen patterns were assessed in light and dark conditions and under varying flow regimes. The images show discrete high oxygen concentration regions above the organisms during lighted periods and low oxygen in the dark. Size and orientation of these areas were dependent on flow regime. For corals and algae in close proximity the 2D optodes show areas of extremely low oxygen concentration at the interaction interfaces under both dark (18.4 ± 7.7 µmol O2 L- 1) and daylight (97.9 ± 27.5 µmol O2 L- 1) conditions. These images present the first two-dimensional visualization of oxygen gradients generated by benthic reef algae and corals under varying flow conditions and provide a 2D depiction of previously observed hypoxic zones at coral algae interfaces. This approach allows for visualization of locally confined, distinctive alterations of oxygen concentrations facilitated by benthic organisms and provides compelling evidence for hypoxic conditions at coral-algae interaction zones. PMID:23882443

  8. Visual search automation for unmanned aerial vehicles

    Microsoft Academic Search

    ERIC N. JOHNSON; ALISON A. PROCTOR; Jincheol Ha; ALLEN R. TANNENBAUM

    2005-01-01

    The design, development, and testing of an unmanned aerial vehicle (UAV) with automated capabilities is described: searching a prescribed area, identifying a specific building within that area based on a small sign located on one wall, and then identifying an opening into that building. This includes a description of the automated search system along with simulation and flight test results.

  9. Visual Search Asymmetry with Uncertain Targets

    ERIC Educational Resources Information Center

    Saiki, Jun; Koike, Takahiko; Takahashi, Kohske; Inoue, Tomoko

    2005-01-01

    The underlying mechanism of search asymmetry is still unknown. Many computational models postulate top-down selection of target-defining features as a crucial factor. This feature selection account implies, and other theories implicitly assume, that predefined target identity is necessary for search asymmetry. The authors tested the validity of…

  10. Matched filtering determines human visual search in natural images

    NASA Astrophysics Data System (ADS)

    Toet, Alexander

    2011-05-01

    The structural image similarity index (SSIM), introduced by Wang and Bovik (IEEE Signal Processing Letters 9-3, pp. 81-84, 2002) measures the similarity between images in terms of luminance, contrast en structure. It has successfully been deployed to model human visual perception of image distortions and modifications in a wide range of different imaging applications. Chang and Zhang (Infrared Physics & Technology 51-2, pp. 83-90, 2007) recently introduced the target structural similarity (TSSIM) clutter metric, which deploys the SSIM to quantify the similarity of a target to its background in terms of luminance, contrast en structure. They showed that the TSSIM correlates significantly with mean search time and detection probability. However, it is not immediately obvious to what extent each of the three TSSIM components contributes to this correlation. Here we evaluate the TSSIM by deploying it to a set of natural images for which human visual search data are available: the Search_2 dataset. By analyzing the predictive performance of each of the three TSSIM components, we find that it is predominantly the structural similarity component which determines human visual search performance, whereas the luminance and contrast components of the TSSIM show no relation with human performance. Since the structural similarity component of the TSSIM is equivalent to a matched filter, it appears that matched filtering predicts human visual performance when searching for a known target.

  11. Crowded visual search in children with normal vision and children with visual impairment.

    PubMed

    Huurneman, Bianca; Cox, Ralf F A; Vlaskamp, Björn N S; Boonstra, F Nienke

    2014-03-01

    This study investigates the influence of oculomotor control, crowding, and attentional factors on visual search in children with normal vision ([NV], n=11), children with visual impairment without nystagmus ([VI-nys], n=11), and children with VI with accompanying nystagmus ([VI+nys], n=26). Exclusion criteria for children with VI were: multiple impairments and visual acuity poorer than 20/400 or better than 20/50. Three search conditions were presented: a row with homogeneous distractors, a matrix with homogeneous distractors, and a matrix with heterogeneous distractors. Element spacing was manipulated in 5 steps from 2 to 32 minutes of arc. Symbols were sized 2 times the threshold acuity to guarantee visibility for the VI groups. During simple row and matrix search with homogeneous distractors children in the VI+nys group were less accurate than children with NV at smaller spacings. Group differences were even more pronounced during matrix search with heterogeneous distractors. Search times were longer in children with VI compared to children with NV. The more extended impairments during serial search reveal greater dependence on oculomotor control during serial compared to parallel search. PMID:24456806

  12. Visual Exploratory Search of Relationship Graphs on Smartphones

    PubMed Central

    Ouyang, Jianquan; Zheng, Hao; Kong, Fanbin; Liu, Tianming

    2013-01-01

    This paper presents a novel framework for Visual Exploratory Search of Relationship Graphs on Smartphones (VESRGS) that is composed of three major components: inference and representation of semantic relationship graphs on the Web via meta-search, visual exploratory search of relationship graphs through both querying and browsing strategies, and human-computer interactions via the multi-touch interface and mobile Internet on smartphones. In comparison with traditional lookup search methodologies, the proposed VESRGS system is characterized with the following perceived advantages. 1) It infers rich semantic relationships between the querying keywords and other related concepts from large-scale meta-search results from Google, Yahoo! and Bing search engines, and represents semantic relationships via graphs; 2) the exploratory search approach empowers users to naturally and effectively explore, adventure and discover knowledge in a rich information world of interlinked relationship graphs in a personalized fashion; 3) it effectively takes the advantages of smartphones’ user-friendly interfaces and ubiquitous Internet connection and portability. Our extensive experimental results have demonstrated that the VESRGS framework can significantly improve the users’ capability of seeking the most relevant relationship information to their own specific needs. We envision that the VESRGS framework can be a starting point for future exploration of novel, effective search strategies in the mobile Internet era. PMID:24223936

  13. Visualizing patterns of craniofacial shape variation in Homo sapiens.

    PubMed Central

    Zollikofer, Christoph P E; Ponce De León, Marcia S

    2002-01-01

    The geometric morphometric analysis of shape variation in complex biological structures such as the human skull poses a number of specific challenges: the registration of homologous morphologies, the treatment of bilateral symmetry, the graphical representation of form variability in three dimensions and the interpretation of the results in terms of differential growth processes. To visualize complex patterns of shape change, we propose an alternative to classical Cartesian deformation grids in the style of D'Arcy W. Thompson. Reference to the surface structures of the organism under investigation permits a comprehensive visual grasp of shape change and its tentative interpretation in terms of differential growth. The application of this method to the analysis of human craniofacial shape variation reveals distinct modes of growth and development of the neurocranial and viscerocranial regions of the skull. Our data further indicate that variations in the orientation of the viscerocranium relative to the neurocranium impinge on the shapes of the face and the cranial vault. PMID:11958711

  14. Local visual energy mechanisms revealed by detection of global patterns.

    PubMed

    Morgenstern, Yaniv; Elder, James H

    2012-03-14

    A central goal of visual neuroscience is to relate the selectivity of individual neurons to perceptual judgments, such as detection of a visual pattern at low contrast or in noise. Since neurons in early areas of visual cortex carry information only about a local patch of the image, detection of global patterns must entail spatial pooling over many such neurons. Physiological methods provide access to local detection mechanisms at the single-neuron level but do not reveal how neural responses are combined to determine the perceptual decision. Behavioral methods provide access to perceptual judgments of a global stimulus but typically do not reveal the selectivity of the individual neurons underlying detection. Here we show how the existence of a nonlinearity in spatial pooling does allow properties of these early mechanisms to be estimated from behavioral responses to global stimuli. As an example, we consider detection of large-field sinusoidal gratings in noise. Based on human behavioral data, we estimate the length and width tuning of the local detection mechanisms and show that it is roughly consistent with the tuning of individual neurons in primary visual cortex of primate. We also show that a local energy model of pooling based on these estimated receptive fields is much more predictive of human judgments than competing models, such as probability summation. In addition to revealing underlying properties of early detection and spatial integration mechanisms in human cortex, our findings open a window on new methods for relating system-level perceptual judgments to neuron-level processing. PMID:22423090

  15. Operator Choice Modeling for Collaborative UAV Visual Search Tasks

    E-print Network

    Cummings, Mary "Missy"

    mutiple UAV mission. Our results suggest that while requeueing can improve detection accuracy and decreaseOperator Choice Modeling for Collaborative UAV Visual Search Tasks Luca F. Bertuccelli Member, IEEE, and Mary L. Cummings Senior Member, IEEE Abstract--Unmanned Aerial Vehicles (UAVs) provide unprece- dented

  16. Concurrent visual search and time reproduction with cross-talk

    Microsoft Academic Search

    Richard Schweickert; Claudette Fortin; Kyongje Sung

    2007-01-01

    Previous experiments indicate that humans can reproduce a time interval while concurrently searching a visual display presented near the beginning of the reproduced interval (Fortin, C., Rousseau, R., Bourque, P. & Kirouac, E. (1993). Time estimation and concurrent nontemporal processing: Specific interference from short-term-memory demands. Perception & Psychophysics, 53, 536–548.). In the earlier experiments, reproduced intervals were either insensitive to

  17. Continuous processing in macaque frontal cortex during visual search

    Microsoft Academic Search

    Narcisse P. Bichot; S. Chenchal Rao; Jeffrey D. Schall

    2001-01-01

    A central issue in mental chronometry is whether information is transferred between processing stages such as stimulus evaluation and response preparation in a continuous or discrete manner. We tested whether partial information about a stimulus influences the response stage by recording the activity of movement-related neurons in the frontal eye field of macaque monkeys performing a conjunction visual search and

  18. Monitoring mechanisms in visual search: an fMRI study.

    PubMed

    Vallesi, Antonino

    2014-09-01

    This fMRI study investigates the neural underpinning and the cognitive factors associated with monitoring in visual search. A visual search task was designed by pseudo-randomly mixing four experimental conditions, which were obtained through the factorial combination of salience (pop-out vs. non pop-out) and target presence (present vs. absent). The fastest responses were obtained when a salient target was presented, while responses were slowest with target-absent conditions, which required extensive evaluation of the visual scene. Partial Least Square multivariate analysis was used to analyze the fMRI data. The first Latent Variable revealed a set of fronto-parietal and occipital regions, which was cohesively activated especially when the presence of the target stimulus was not easy to discard, such as when all stimuli in the visual scene were non-targets or when one stimulus among the rest was salient (pop-out) but not a target. The most extensive and robust activation within this cohesive set of regions was located in the right inferior/middle frontal gyrus. This finding corroborates evidence in favor of a role of the right lateral prefrontal cortex, and associated regions, for evaluative operations, extending previous findings to the visual search domain. PMID:25046361

  19. Accurate expectancies diminish perceptual distraction during visual search.

    PubMed

    Sy, Jocelyn L; Guerin, Scott A; Stegman, Anna; Giesbrecht, Barry

    2014-01-01

    The load theory of visual attention proposes that efficient selective perceptual processing of task-relevant information during search is determined automatically by the perceptual demands of the display. If the perceptual demands required to process task-relevant information are not enough to consume all available capacity, then the remaining capacity automatically and exhaustively "spills-over" to task-irrelevant information. The spill-over of perceptual processing capacity increases the likelihood that task-irrelevant information will impair performance. In two visual search experiments, we tested the automaticity of the allocation of perceptual processing resources by measuring the extent to which the processing of task-irrelevant distracting stimuli was modulated by both perceptual load and top-down expectations using behavior, functional magnetic resonance imaging, and electrophysiology. Expectations were generated using a trial-by-trial cue that provided information about the likely load of the upcoming visual search task. When the cues were valid, behavioral interference was eliminated and the influence of load on frontoparietal and visual cortical responses was attenuated relative to when the cues were invalid. In conditions in which task-irrelevant information interfered with performance and modulated visual activity, individual differences in mean blood oxygenation level dependent responses measured from the left intraparietal sulcus were negatively correlated with individual differences in the severity of distraction. These results are consistent with the interpretation that a top-down biasing mechanism interacts with perceptual load to support filtering of task-irrelevant information. PMID:24904374

  20. Accurate expectancies diminish perceptual distraction during visual search

    PubMed Central

    Sy, Jocelyn L.; Guerin, Scott A.; Stegman, Anna; Giesbrecht, Barry

    2014-01-01

    The load theory of visual attention proposes that efficient selective perceptual processing of task-relevant information during search is determined automatically by the perceptual demands of the display. If the perceptual demands required to process task-relevant information are not enough to consume all available capacity, then the remaining capacity automatically and exhaustively “spills-over” to task-irrelevant information. The spill-over of perceptual processing capacity increases the likelihood that task-irrelevant information will impair performance. In two visual search experiments, we tested the automaticity of the allocation of perceptual processing resources by measuring the extent to which the processing of task-irrelevant distracting stimuli was modulated by both perceptual load and top-down expectations using behavior, functional magnetic resonance imaging, and electrophysiology. Expectations were generated using a trial-by-trial cue that provided information about the likely load of the upcoming visual search task. When the cues were valid, behavioral interference was eliminated and the influence of load on frontoparietal and visual cortical responses was attenuated relative to when the cues were invalid. In conditions in which task-irrelevant information interfered with performance and modulated visual activity, individual differences in mean blood oxygenation level dependent responses measured from the left intraparietal sulcus were negatively correlated with individual differences in the severity of distraction. These results are consistent with the interpretation that a top-down biasing mechanism interacts with perceptual load to support filtering of task-irrelevant information. PMID:24904374

  1. Interactive Data Visualization and Pattern Discovery with Mirage

    NASA Astrophysics Data System (ADS)

    Ho, T. K.

    2007-11-01

    Pattern discovery often occurs in studying correlations of data viewed from multiple perspectives. For high dimensional, low level sensory data such as images, it is especially important that the input can be examined in its raw form, along with features extracted according to the application's concern, plus all intermediate results of manual or automatic analysis. To facilitate this, flexible and effective exploratory tools that can handle diverse data types, a wide range of objectives, large data volumes, and variable demands on speed are in critical need. I describe our experience with Mirage, a research software tool for open-ended interactive pattern discovery. Applications to analyzing photonics simulations and in the Virtual Observatory raised interesting challenges on the tool's organization and the data visualization algorithms. We describe our progress on designing effective modularization and connection interfaces to local or remote analysis libraries, and approaches to highlighting data relationships between high-dimensional spaces or across contexts of different resolutions and data types.

  2. 3D Pattern of brain abnormalities in williams syndrome Visualized using tensor-based morphometry

    E-print Network

    Thompson, Paul

    Ã?Ã? Ã? Ã?Ã?Ã? Ã? Ã?Ã? 3D Pattern of brain abnormalities in williams syndrome Visualized using tensor., Toga, Arthur W., Thompson, Paul M., 3D Pattern of brain abnormalities in williams syndrome Visualized ABNORMALITIES IN WILLIAMS SYNDROME VISUALIZED USING TENSOR-BASED MORPHOMETRY Ming-Chang Chiang MD1 , Allan L

  3. Visual search for arbitrary objects in real scenes

    PubMed Central

    Alvarez, George A.; Rosenholtz, Ruth; Kuzmova, Yoana I.; Sherman, Ashley M.

    2011-01-01

    How efficient is visual search in real scenes? In searches for targets among arrays of randomly placed distractors, efficiency is often indexed by the slope of the reaction time (RT) × Set Size function. However, it may be impossible to define set size for real scenes. As an approximation, we hand-labeled 100 indoor scenes and used the number of labeled regions as a surrogate for set size. In Experiment 1, observers searched for named objects (a chair, bowl, etc.). With set size defined as the number of labeled regions, search was very efficient (~5 ms/item). When we controlled for a possible guessing strategy in Experiment 2, slopes increased somewhat (~15 ms/item), but they were much shallower than search for a random object among other distinctive objects outside of a scene setting (Exp. 3: ~40 ms/item). In Experiments 4–6, observers searched repeatedly through the same scene for different objects. Increased familiarity with scenes had modest effects on RTs, while repetition of target items had large effects (>500 ms). We propose that visual search in scenes is efficient because scene-specific forms of attentional guidance can eliminate most regions from the “functional set size” of items that could possibly be the target. PMID:21671156

  4. The role of memory for visual search in scenes.

    PubMed

    Le-Hoa Võ, Melissa; Wolfe, Jeremy M

    2015-03-01

    Many daily activities involve looking for something. The ease with which these searches are performed often allows one to forget that searching represents complex interactions between visual attention and memory. Although a clear understanding exists of how search efficiency will be influenced by visual features of targets and their surrounding distractors or by the number of items in the display, the role of memory in search is less well understood. Contextual cueing studies have shown that implicit memory for repeated item configurations can facilitate search in artificial displays. When searching more naturalistic environments, other forms of memory come into play. For instance, semantic memory provides useful information about which objects are typically found where within a scene, and episodic scene memory provides information about where a particular object was seen the last time a particular scene was viewed. In this paper, we will review work on these topics, with special emphasis on the role of memory in guiding search in organized, real-world scenes. PMID:25684693

  5. History effects in visual search for monsters: Search times, choice biases, and liking.

    PubMed

    Chetverikov, Andrey; Kristjansson, Árni

    2015-02-01

    Repeating targets and distractors on consecutive visual search trials facilitates search performance, whereas switching targets and distractors harms search. In addition, search repetition leads to biases in free choice tasks, in that previously attended targets are more likely to be chosen than distractors. Another line of research has shown that attended items receive high liking ratings, whereas ignored distractors are rated negatively. Potential relations between the three effects are unclear, however. Here we simultaneously measured repetition benefits and switching costs for search times, choice biases, and liking ratings in color singleton visual search for "monster" shapes. We showed that if expectations from search repetition are violated, targets are liked to be less attended than otherwise. Choice biases were, on the other hand, affected by distractor repetition, but not by target/distractor switches. Target repetition speeded search times but had little influence on choice or liking. Our findings suggest that choice biases reflect distractor inhibition, and liking reflects the conflict associated with attending to previously inhibited stimuli, while speeded search follows both target and distractor repetition. Our results support the newly proposed affective-feedback-of-hypothesis-testing account of cognition, and additionally, shed new light on the priming of visual search. PMID:25338539

  6. Visual search for simple volumetric shapes.

    PubMed

    Brown, J M; Weisstein, N; May, J G

    1992-01-01

    Five experiments measured reaction time (RT) to detect the presence or absence of a simple volumetric shape (target) dependent on the number of display items (distractors) and their depicted three-dimensional (3-D) orientation. Experiments 1-4 examined every pairwise combination of two different simple volumetric shapes in two 3-D orientations. Conditions exhibiting "pop-out" could be predicted by differences in their two-dimensional (2-D) features. Conditions in which search was slower support previously found search asymmetries for particular 2-D features. When the distractors were a mixture of the other shapes in the same 3-D orientation, search was serial, except when the target had a curved principal axis (Experiment 5). The results suggest that these simple volumetric shapes are not processed preattentively. PMID:1549423

  7. Is pop-out visual search attentive or preattentive? Yes!

    PubMed

    Lagroix, Hayley E P; Di Lollo, Vincent; Spalek, Thomas M

    2015-04-01

    Is the efficiency of "pop-out" visual search impaired when attention is preempted by another task? This question has been raised in earlier experiments but has not received a satisfactory answer. To constrain the availability of attention, those experiments employed an attentional blink (AB) paradigm in which report of the second of 2 targets (T2) is impaired when it is presented shortly after the first (T1). In those experiments, T2 was a pop-out search display that remained on view until response. The main finding was that search efficiency, as indexed by the slope of the search function, was not impaired during the period of the AB. With such long displays, however, the search could be postponed until T1 had been processed, thus allowing the task to be performed with full attention. That pitfall was avoided in the present Experiment 1 by presenting the search array either until response (thus allowing a postponement strategy) or very briefly (making that strategy ineffectual). Level of performance was impaired during the period of the AB, but search efficiency was unimpaired even when the display was brief. Experiment 2 showed that visual search is indeed postponed during the period of the AB, when the array remains on view until response. These findings reveal the action of at least 2 separable mechanisms, indexed by level and efficiency of pop-out search, which are affected in different ways by the availability of attention. The Guided Search 4.0 model can account for the results in both level and efficiency. (PsycINFO Database Record PMID:25706768

  8. Animating streamlines with repeated asymmetric patterns for steady flow visualization

    NASA Astrophysics Data System (ADS)

    Yeh, Chih-Kuo; Liu, Zhanping; Lee, Tong-Yee

    2012-01-01

    Animation provides intuitive cueing for revealing essential spatial-temporal features of data in scientific visualization. This paper explores the design of Repeated Asymmetric Patterns (RAPs) in animating evenly-spaced color-mapped streamlines for dense accurate visualization of complex steady flows. We present a smooth cyclic variable-speed RAP animation model that performs velocity (magnitude) integral luminance transition on streamlines. This model is extended with inter-streamline synchronization in luminance varying along the tangential direction to emulate orthogonal advancing waves from a geometry-based flow representation, and then with evenly-spaced hue differing in the orthogonal direction to construct tangential flow streaks. To weave these two mutually dual sets of patterns, we propose an energy-decreasing strategy that adopts an iterative yet efficient procedure for determining the luminance phase and hue of each streamline in HSL color space. We also employ adaptive luminance interleaving in the direction perpendicular to the flow to increase the contrast between streamlines.

  9. Dynamic Analysis and Pattern Visualization of Forest Fires

    PubMed Central

    Lopes, António M.; Tenreiro Machado, J. A.

    2014-01-01

    This paper analyses forest fires in the perspective of dynamical systems. Forest fires exhibit complex correlations in size, space and time, revealing features often present in complex systems, such as the absence of a characteristic length-scale, or the emergence of long range correlations and persistent memory. This study addresses a public domain forest fires catalogue, containing information of events for Portugal, during the period from 1980 up to 2012. The data is analysed in an annual basis, modelling the occurrences as sequences of Dirac impulses with amplitude proportional to the burnt area. First, we consider mutual information to correlate annual patterns. We use visualization trees, generated by hierarchical clustering algorithms, in order to compare and to extract relationships among the data. Second, we adopt the Multidimensional Scaling (MDS) visualization tool. MDS generates maps where each object corresponds to a point. Objects that are perceived to be similar to each other are placed on the map forming clusters. The results are analysed in order to extract relationships among the data and to identify forest fire patterns. PMID:25137393

  10. Rapid Resumption of Interrupted Search Is Independent of Age-Related Improvements in Visual Search

    ERIC Educational Resources Information Center

    Lleras, Alejandro; Porporino, Mafalda; Burack, Jacob A.; Enns, James T.

    2011-01-01

    In this study, 7-19-year-olds performed an interrupted visual search task in two experiments. Our question was whether the tendency to respond within 500 ms after a second glimpse of a display (the "rapid resumption" effect ["Psychological Science", 16 (2005) 684-688]) would increase with age in the same way as overall search efficiency. The…

  11. Visual search for natural grains in pigeons (Columba livia): Search images and selective attention

    Microsoft Academic Search

    Cynthia M. Langley; Donald A. Riley; Alan B. Bond; Namni Goel

    1996-01-01

    The experiments reported here were designed to test the suggestion of many researchers that selective attention to visual features of a prey can account for search-image effects. In 3 experiments pigeons ate wheat and vetch grains presented on multicolored and gray gravel trays. In Experiment 1 search-image effects were evident when grains were cryptic but not when they were conspicuous.

  12. Results Results Measuring the Timecourse of Guidance in Visual SearchMeasuring the Timecourse of Guidance in Visual Search

    E-print Network

    Measuring the Timecourse of Guidance in Visual Search Evan Palmer1,2 , Michael Van Wert1 , Todd Horowitz1,2 , and Jeremy Wolfe1,2 Evan Palmer1,2 , Michael Van Wert1 , Todd Horowitz1,2 , and Jeremy Wolfe1,2 2 Harvard Medical

  13. Task Specificity and the Influence of Memory on Visual Search: Comment on V and Wolfe (2012)

    E-print Network

    Hollingworth, Andrew

    a preview session, in which participants saw the relevant scenes but did not engage in search, wouldCOMMENTARY Task Specificity and the Influence of Memory on Visual Search: Comment on Võ and Wolfe that the application of memory to visual search may be task specific: Previous experience searching for an object

  14. Video Google: Efficient Visual Search of Videos

    Microsoft Academic Search

    Josef Sivic; Andrew Zisserman

    2006-01-01

    We describe an approach to object retrieval which searches for and localizes all the occurrences of an object in a video, given a query image of the object. The object is represented by a set of viewpoint invariant region descriptors so that recognition can proceed successfully despite changes in viewpoint, illumination and partial occlusion. The temporal continuity of the video

  15. Efficient Visual Search for Objects in Videos

    Microsoft Academic Search

    Josef Sivic; Andrew Zisserman

    2008-01-01

    We describe an approach to generalize the concept of text-based search to nontextual information. In particular, we elaborate on the possibilities of retrieving objects or scenes in a movie with the ease, speed, and accuracy with which Google retrieves web pages containing particular words, by specifying the query as an image of the object or scene. In our approach, each

  16. Curious George: An Integrated Visual Search Platform

    Microsoft Academic Search

    David Meger; Marius Muja; Scott Helmer; Ankur Gupta; Catherine Gamroth; Tomas Hoffman; Matthew Baumann; Tristram Southey; Pooyan Fazli; Walter Wohlkinger; Pooja Viswanathan; James J. Little; David G. Lowe; James Orwell

    2010-01-01

    This paper describes an integrated robot system, known as Curious George, that has demonstrated state-of-the-art capabilities to recognize objects in the real world. We describe the capabilities of this system, including: the ability to access web-based training data automatically and in near real-time, the ability to model the visual appearance and 3D shape of a wide variety of object categories,

  17. The prevalence effect in lateral masking and its relevance for visual search.

    PubMed

    Geelen, B P; Wertheim, A H

    2015-04-01

    In stimulus displays with or without a single target amid 1,644 identical distractors, target prevalence was varied between 20, 50 and 80 %. Maximum gaze deviation was measured to determine the strength of lateral masking in these arrays. The results show that lateral masking was strongest in the 20 % prevalence condition, which differed significantly from both the 50 and 80 % prevalence conditions. No difference was observed between the latter two. This pattern of results corresponds to that found in the literature on the prevalence effect in visual search (stronger lateral masking corresponding to longer search times). The data add to similar findings reported earlier (Wertheim et al. in Exp Brain Res, 170:387-402, 2006), according to which the effects of many well-known factors in visual search correspond to those on lateral masking. These were the effects of set size, disjunctions versus conjunctions, display area, distractor density, the asymmetry effect (Q vs. O's) and viewing distance. The present data, taken together with those earlier findings, may lend credit to a causal hypothesis that lateral masking could be a more important mechanism in visual search than usually assumed. PMID:25567088

  18. Widespread correlation patterns of fMRI signal across visual cortex reflect eccentricity organization.

    PubMed

    Arcaro, Michael J; Honey, Christopher J; Mruczek, Ryan Eb; Kastner, Sabine; Hasson, Uri

    2015-01-01

    The human visual system can be divided into over two-dozen distinct areas, each of which contains a topographic map of the visual field. A fundamental question in vision neuroscience is how the visual system integrates information from the environment across different areas. Using neuroimaging, we investigated the spatial pattern of correlated BOLD signal across eight visual areas on data collected during rest conditions and during naturalistic movie viewing. The correlation pattern between areas reflected the underlying receptive field organization with higher correlations between cortical sites containing overlapping representations of visual space. In addition, the correlation pattern reflected the underlying widespread eccentricity organization of visual cortex, in which the highest correlations were observed for cortical sites with iso-eccentricity representations including regions with non-overlapping representations of visual space. This eccentricity-based correlation pattern appears to be part of an intrinsic functional architecture that supports the integration of information across functionally specialized visual areas. PMID:25695154

  19. PatternHunter: faster and more sensitive homology search

    Microsoft Academic Search

    Bin Ma; John Tromp; Ming Li

    2002-01-01

    Motivation: Genomics and proteomics studies routinely depend on homology searches based on the strategy of finding short seed matches which are then extended. The exploding genomic data growth presents a dilemma for DNA homology search techniques: increasing seed size decreases sensitivity whereas decreasing seed size slows down computation. Results: We present a new homology search algorithm 'PatternHunter' that uses a

  20. How visual edge features influence cuttlefish camouflage patterning Chuan-Chin Chiao a,b,

    E-print Network

    California at Irvine, University of

    How visual edge features influence cuttlefish camouflage patterning Chuan-Chin Chiao a-bodied cuttlefish. Previous studies have shown that cuttlefish body patterns are strongly influenced by visual edges in the substrate. The aim of the pres- ent study was to examine how cuttlefish body patterning is differentially

  1. Visualization of Orbits and Pattern Evocation for the Double Spherical Pendulum

    E-print Network

    Marsden, Jerrold

    Visualization of Orbits and Pattern Evocation for the Double Spherical Pendulum Jerrold E. Marsden and the visualization of orbits of the double spherical pendulum. Pattern evocation is a phenomenon where patterns of this theory are demonstrated for the double spherical pendulum. A dierential-algebraic model is created

  2. Visualization of Orbits and Pattern Evocation for the Double Spherical Pendulum

    E-print Network

    Wendlandt, Jeff

    Visualization of Orbits and Pattern Evocation for the Double Spherical Pendulum Jerrold E. Marsden pattern evocation and the visualization of orbits of the double spherical pendulum. Pattern evocation or symmetry. Examples of this theory are demonstrated for the double spherical pendulum. A differential

  3. Eye-Search: A web-based therapy that improves visual search in hemianopia

    PubMed Central

    Ong, Yean-Hoon; Jacquin-Courtois, Sophie; Gorgoraptis, Nikos; Bays, Paul M; Husain, Masud; Leff, Alexander P

    2015-01-01

    Persisting hemianopia frequently complicates lesions of the posterior cerebral hemispheres, leaving patients impaired on a range of key activities of daily living. Practice-based therapies designed to induce compensatory eye movements can improve hemianopic patients' visual function, but are not readily available. We used a web-based therapy (Eye-Search) that retrains visual search saccades into patients' blind hemifield. A group of 78 suitable hemianopic patients took part. After therapy (800 trials over 11 days), search times into their impaired hemifield improved by an average of 24%. Patients also reported improvements in a subset of visually guided everyday activities, suggesting that Eye-Search therapy affects real-world outcomes. PMID:25642437

  4. Visual search and the N2pc in children.

    PubMed

    Couperus, Jane W; Quirk, Colin

    2015-04-01

    While there is growing understanding of visual selective attention in children, some aspects such as selection in the presence of distractors are not well understood. Adult studies suggest that when presented with a visual search task, an enhanced negativity is seen beginning around 200 ms (the N2pc) that reflects selection of a target item among distractors. However, it is not known if similar selective attention-related activity is seen in children during visual search. This study was designed to investigate the presence of the N2pc in children. Nineteen children (ages 9-12 years) and 21 adults (ages 18-22 years) completed a visual search task in which they were asked to attend to a fixation surrounded by both a target and a distractor stimulus. Three types of displays were analyzed at parietal electrodes P7 and P8; lateral target/lateral distractor, lateral target/midline distractor, and midline target/lateral distractor. Both adults and children showed a significant increased negativity contralateral compared to ipsilateral to the target (reflected in the N2pc) in both displays with a lateral target while no such effect was seen in displays with a midline target. This suggests that children also utilized additional resources to select a target item when distractors are present. These findings demonstrate that the N2pc can be used as a marker of attentional object selection in children. PMID:25678274

  5. Pictures and words in visual search

    Microsoft Academic Search

    Allan Paivio; Ian Begg

    1974-01-01

    Ss in three experiments searched through an array of pictures or words for a target item that had been presented as a picture\\u000a or a word. In Experiments I and II, the pictures were line drawings of familiar objects and the words were their printed labels;\\u000a in Experiment III, the stimuli were photographs of the faces of famous people and

  6. Evolving the stimulus to fit the brain: A genetic algorithm reveals the brain's feature priorities in visual search.

    PubMed

    Van der Burg, Erik; Cass, John; Theeuwes, Jan; Alais, David

    2015-01-01

    How does the brain find objects in cluttered visual environments? For decades researchers have employed the classic visual search paradigm to answer this question using factorial designs. Although such approaches have yielded important information, they represent only a tiny fraction of the possible parametric space. Here we use a novel approach, by using a genetic algorithm (GA) to discover the way the brain solves visual search in complex environments, free from experimenter bias. Participants searched a series of complex displays, and those supporting fastest search were selected to reproduce (survival of the fittest). Their display properties (genes) were crossed and combined to create a new generation of "evolved" displays. Displays evolved quickly over generations towards a stable, efficiently searched array. Color properties evolved first, followed by orientation. The evolved displays also contained spatial patterns suggesting a coarse-to-fine search strategy. We argue that this behavioral performance-driven GA reveals the way the brain selects information during visual search in complex environments. We anticipate that our approach can be adapted to a variety of sensory and cognitive questions that have proven too intractable for factorial designs. PMID:25761347

  7. Visual search characteristics in mammography: malignant vs benign breast masses

    NASA Astrophysics Data System (ADS)

    Mello-Thoms, Claudia

    2007-03-01

    Mammography screening is the most widely utilized tool to screen for breast cancer. Radiologists read a mammogram using a two-pass strategy where the first pass is guided by salient features of the image (the so-called 'pop-out' elements), and the second pass is a systematic search. It is assumed that most breast masses that are reported by the radiologist are in fact detected during the first pass of this search strategy, and that the second pass is useful for the detection of microcalcification clusters. Furthermore, experiments in other visual domains have shown that observers are attracted faster to incongruous elements in a display than to normal (i.e., more expected) elements. In this sense, it can be argued that benign findings constitute more expected findings, because they encompass a large percentage of all abnormalities found on a mammogram. In this experiment we sought to determine whether the search for malignant masses was indeed faster than the search for benign masses. We also aimed to determine whether the observers' overall visual search behavior was different between benign and malignant cases, not only in terms of how long it took the observers to hit the location of the lesion, but also how long the observers took analyzing the case, how different the distribution of false positive responses were between the two types of cases, etc.

  8. Object-based auditory facilitation of visual search for pictures and words with frequent and rare targets

    PubMed Central

    Iordanescu, Lucica; Grabowecky, Marcia; Suzuki, Satoru

    2010-01-01

    Auditory and visual processes demonstrably enhance each other based on spatial and temporal coincidence. Our recent results on visual search have shown that auditory signals also enhance visual salience of specific objects based on multimodal experience. For example, we tend to see an object (e.g., a cat) and simultaneously hear its characteristic sound (e.g., “meow”), to name an object when we see it, and to vocalize a word when we read it, but we do not tend to see a word (e.g., cat) and simultaneously hear the characteristic sound (e.g., “meow”) of the named object. If auditory-visual enhancements occur based on this pattern of experiential associations, playing a characteristic sound (e.g., “meow”) should facilitate visual search for the corresponding object (e.g., an image of a cat), hearing a name should facilitate visual search for both the corresponding object and corresponding word, but playing a characteristic sound should not facilitate visual search for the name of the corresponding object. Our present and prior results together confirmed these experiential-association predictions. We also recently showed that the underlying object-based auditory-visual interactions occur rapidly (within 220 ms) and guide initial saccades towards target objects. If object-based auditory-visual enhancements are automatic and persistent, an interesting application would be to use characteristic sounds to facilitate visual search when targets are rare, such as during baggage screening. Our participants searched for a gun among other objects when a gun was presented on only 10% of the trials. The search time was speeded when a gun sound was played on every trial (primarily on gun-absent trials); importantly, playing gun sounds facilitated both gun-present and gun-absent responses, suggesting that object-based auditory-visual enhancements persistently increase the detectability of guns rather than simply biasing gun-present responses. Thus, object-based auditory-visual interactions that derive from experiential associations rapidly and persistently increase visual salience of corresponding objects. PMID:20864070

  9. Object-based auditory facilitation of visual search for pictures and words with frequent and rare targets.

    PubMed

    Iordanescu, Lucica; Grabowecky, Marcia; Suzuki, Satoru

    2011-06-01

    Auditory and visual processes demonstrably enhance each other based on spatial and temporal coincidence. Our recent results on visual search have shown that auditory signals also enhance visual salience of specific objects based on multimodal experience. For example, we tend to see an object (e.g., a cat) and simultaneously hear its characteristic sound (e.g., "meow"), to name an object when we see it, and to vocalize a word when we read it, but we do not tend to see a word (e.g., cat) and simultaneously hear the characteristic sound (e.g., "meow") of the named object. If auditory-visual enhancements occur based on this pattern of experiential associations, playing a characteristic sound (e.g., "meow") should facilitate visual search for the corresponding object (e.g., an image of a cat), hearing a name should facilitate visual search for both the corresponding object and corresponding word, but playing a characteristic sound should not facilitate visual search for the name of the corresponding object. Our present and prior results together confirmed these experiential association predictions. We also recently showed that the underlying object-based auditory-visual interactions occur rapidly (within 220ms) and guide initial saccades towards target objects. If object-based auditory-visual enhancements are automatic and persistent, an interesting application would be to use characteristic sounds to facilitate visual search when targets are rare, such as during baggage screening. Our participants searched for a gun among other objects when a gun was presented on only 10% of the trials. The search time was speeded when a gun sound was played on every trial (primarily on gun-absent trials); importantly, playing gun sounds facilitated both gun-present and gun-absent responses, suggesting that object-based auditory-visual enhancements persistently increase the detectability of guns rather than simply biasing gun-present responses. Thus, object-based auditory-visual interactions that derive from experiential associations rapidly and persistently increase visual salience of corresponding objects. PMID:20864070

  10. Pie Charts for Visualizing Query Term Frequency in Search Results

    Microsoft Academic Search

    Terry J. Anderson; Ali Hussam; Bill Plummer; Nathan Jacobs

    2002-01-01

    Search engine queries are normally brief but often return\\u000a unmanageably long results, with which users struggle to determine\\u000a document quality and relevance. In recent years, many studies\\u000a have enhanced search results with metadata displayed as visual\\u000a cues. Their success in helping users make faster and more\\u000a accurate document judgments has been uneven, reflecting the wide\\u000a range of information needs and

  11. Visual Iconic Patterns of Instant Messaging: Steps Towards Understanding Visual Conversations

    NASA Astrophysics Data System (ADS)

    Bays, Hillary

    An Instant Messaging (IM) conversation is a dynamic communication register made up of text, images, animation and sound played out on a screen with potentially several parallel conversations and activities all within a physical environment. This article first examines how best to capture this unique gestalt using in situ recording techniques (video, screen capture, XML logs) which highlight the micro-phenomenal level of the exchange and the macro-social level of the interaction. Of particular interest are smileys first as cultural artifacts in CMC in general then as linguistic markers. A brief taxonomy of these markers is proposed in an attempt to clarify their frequency and patterns of their use. Then, focus is placed on their importance as perceptual cues which facilitate communication, while also serving as emotive and emphatic functional markers. We try to demonstrate that the use of smileys and animation is not arbitrary but an organized interactional and structured practice. Finally, we discuss how the study of visual markers in IM could inform the study of other visual conversation codes, such as sign languages, which also have co-produced, physical behavior, suggesting the possibility of a visual phonology.

  12. What can 1 billion trials tell us about visual search?

    PubMed

    Mitroff, Stephen R; Biggs, Adam T; Adamo, Stephen H; Dowd, Emma Wu; Winkle, Jonathan; Clark, Kait

    2015-02-01

    Mobile technology (e.g., smartphones and tablets) has provided psychologists with a wonderful opportunity: through careful design and implementation, mobile applications can be used to crowd source data collection. By garnering massive amounts of data from a wide variety of individuals, it is possible to explore psychological questions that have, to date, been out of reach. Here we discuss 2 examples of how data from the mobile game Airport Scanner (Kedlin Co., http://www.airportscannergame.com) can be used to address questions about the nature of visual search that pose intractable problems for laboratory-based research. Airport Scanner is a successful mobile game with millions of unique users and billions of individual trials, which allows for examining nuanced visual search questions. The goals of the current Observation Report were to highlight the growing opportunity that mobile technology affords psychological research and to provide an example roadmap of how to successfully collect usable data. PMID:25485661

  13. Attentional set interacts with perceptual load in visual search

    Microsoft Academic Search

    Jan Theeuwes; Arthur F. Kramer; Artem V. Belopolsky

    2004-01-01

    In the present study, we examined the hypothesis that perceptual load is the primary factor that determines the efficiency\\u000a of attentional selection. Participants performed a visual search task under conditions of high- and low-load. In line with\\u000a the perceptual load hypothesis, presenting conditions of highand low-load in separate blocks of trials resulted in processing\\u000a of to-be-ignored stimuli only in the

  14. Searching for Pulsars Using Image Pattern Recognition

    NASA Astrophysics Data System (ADS)

    Zhu, W. W.; Berndsen, A.; Madsen, E. C.; Tan, M.; Stairs, I. H.; Brazier, A.; Lazarus, P.; Lynch, R.; Scholz, P.; Stovall, K.; Ransom, S. M.; Banaszak, S.; Biwer, C. M.; Cohen, S.; Dartez, L. P.; Flanigan, J.; Lunsford, G.; Martinez, J. G.; Mata, A.; Rohr, M.; Walker, A.; Allen, B.; Bhat, N. D. R.; Bogdanov, S.; Camilo, F.; Chatterjee, S.; Cordes, J. M.; Crawford, F.; Deneva, J. S.; Desvignes, G.; Ferdman, R. D.; Freire, P. C. C.; Hessels, J. W. T.; Jenet, F. A.; Kaplan, D. L.; Kaspi, V. M.; Knispel, B.; Lee, K. J.; van Leeuwen, J.; Lyne, A. G.; McLaughlin, M. A.; Siemens, X.; Spitler, L. G.; Venkataraman, A.

    2014-02-01

    In the modern era of big data, many fields of astronomy are generating huge volumes of data, the analysis of which can sometimes be the limiting factor in research. Fortunately, computer scientists have developed powerful data-mining techniques that can be applied to various fields. In this paper, we present a novel artificial intelligence (AI) program that identifies pulsars from recent surveys by using image pattern recognition with deep neural nets—the PICS (Pulsar Image-based Classification System) AI. The AI mimics human experts and distinguishes pulsars from noise and interference by looking for patterns from candidate plots. Different from other pulsar selection programs that search for expected patterns, the PICS AI is taught the salient features of different pulsars from a set of human-labeled candidates through machine learning. The training candidates are collected from the Pulsar Arecibo L-band Feed Array (PALFA) survey. The information from each pulsar candidate is synthesized in four diagnostic plots, which consist of image data with up to thousands of pixels. The AI takes these data from each candidate as its input and uses thousands of such candidates to train its ~9000 neurons. The deep neural networks in this AI system grant it superior ability to recognize various types of pulsars as well as their harmonic signals. The trained AI's performance has been validated with a large set of candidates from a different pulsar survey, the Green Bank North Celestial Cap survey. In this completely independent test, the PICS ranked 264 out of 277 pulsar-related candidates, including all 56 previously known pulsars and 208 of their harmonics, in the top 961 (1%) of 90,008 test candidates, missing only 13 harmonics. The first non-pulsar candidate appears at rank 187, following 45 pulsars and 141 harmonics. In other words, 100% of the pulsars were ranked in the top 1% of all candidates, while 80% were ranked higher than any noise or interference. The performance of this system can be improved over time as more training data are accumulated. This AI system has been integrated into the PALFA survey pipeline and has discovered six new pulsars to date.

  15. Levy flight as a robotic search pattern

    E-print Network

    Saldivar, Orlando

    2012-01-01

    Levy flights have been recently found to approximate the trajectories of animal foragers in their search for resources and food. Levy flights have proved to be effective in searching tasks because of their characteristic ...

  16. How Temporal and Spatial Aspects of Presenting Visualizations Affect Learning about Locomotion Patterns

    ERIC Educational Resources Information Center

    Imhof, Birgit; Scheiter, Katharina; Edelmann, Jorg; Gerjets, Peter

    2012-01-01

    Two studies investigated the effectiveness of dynamic and static visualizations for a perceptual learning task (locomotion pattern classification). In Study 1, seventy-five students viewed either dynamic, static-sequential, or static-simultaneous visualizations. For tasks of intermediate difficulty, dynamic visualizations led to better…

  17. LOCAL DENSITY GUIDES VISUAL SEARCH: SPARSE GROUPS ARE FIRST AND FASTER

    E-print Network

    Hornof, Anthony

    modeling to investigate the effect of local density on the visual search of structured layouts of words, and searched sparse groups before dense groups. Participants made slightly more fixations per word in sparse strip. Ojanpää, Näsänen, and Kojo (2002) studied the effect of spacing on the visual search of word

  18. Searching for Signs, Symbols, and Icons: Effects of Time of Day, Visual Complexity, and Grouping

    ERIC Educational Resources Information Center

    McDougall, Sine; Tyrer, Victoria; Folkard, Simon

    2006-01-01

    Searching for icons, symbols, or signs is an integral part of tasks involving computer or radar displays, head-up displays in aircraft, or attending to road traffic signs. Icons therefore need to be designed to optimize search times, taking into account the factors likely to slow down visual search. Three factors likely to adversely affect visual

  19. QueryMarvel: A visual query language for temporal patterns using comic strips

    Microsoft Academic Search

    Jing Jin; Pedro A. Szekely

    2009-01-01

    In many domains, decision makers want to find and understand patterns of events as these patterns often give insight into the causal relationships among events. Current systems to specify patterns are either too difficult to use or only support simple patterns. We present QueryMarvel, an interactive visual query environment that allows ordinary users to easily and efficiently specify complex temporal

  20. Surgically created neural pathways mediate visual pattern discrimination

    NASA Astrophysics Data System (ADS)

    Frost, Douglas O.; Boire, Denis; Gingras, Guy; Ptito, Maurice

    2000-09-01

    Combined lesions of retinal targets and ascending auditory pathways can induce, in developing animals, permanent retinal projections to auditory thalamic nuclei and to visual thalamic nuclei that normally receive little direct retinal input. Neurons in the auditory cortex of such animals have visual response properties that resemble those of neurons in the primary visual cortex of normal animals. Therefore, we investigated the behavioral function of the surgically induced retino-thalamo-cortical pathways. We showed that both surgically induced pathways can mediate visually guided behaviors whose normal substrate, the pathway from the retina to the primary visual cortex via the primary thalamic visual nucleus, is missing.

  1. Continuous Subgraph Pattern Search over Certain and Uncertain Graph Streams

    Microsoft Academic Search

    Lei Chen; Changliang Wang

    2010-01-01

    Search over graph databases has attracted much attention recently due to its usefulness in many fields, such as the analysis of chemical compounds, intrusion detection in network traffic data, and pattern matching over users' visiting logs. However, most of the existing works focus on search over static graph databases, while in many real applications, graphs are changing over time. In

  2. Patterns of Search: Analyzing and Modeling Web Query Refinement

    Microsoft Academic Search

    Tessa Lau; Eric Horvitz

    1998-01-01

    We discuss the construction of probabilistic models centering on temporal pat- terns of query refinement. Our analyses are derived from a large corpus of Web search queries extracted from server logs recorded by a popular Internet search service. We frame the modeling task in terms of pursuing an understanding of probabilistic relationships among temporal patterns of activity, informational goals, and

  3. Visual height intolerance and acrophobia: clinical characteristics and comorbidity patterns.

    PubMed

    Kapfhammer, Hans-Peter; Huppert, Doreen; Grill, Eva; Fitz, Werner; Brandt, Thomas

    2014-09-28

    The purpose of this study was to estimate the general population lifetime and point prevalence of visual height intolerance and acrophobia, to define their clinical characteristics, and to determine their anxious and depressive comorbidities. A case-control study was conducted within a German population-based cross-sectional telephone survey. A representative sample of 2,012 individuals aged 14 and above was selected. Defined neurological conditions (migraine, Menière's disease, motion sickness), symptom pattern, age of first manifestation, precipitating height stimuli, course of illness, psychosocial impairment, and comorbidity patterns (anxiety conditions, depressive disorders according to DSM-IV-TR) for vHI and acrophobia were assessed. The lifetime prevalence of vHI was 28.5 % (women 32.4 %, men 24.5 %). Initial attacks occurred predominantly (36 %) in the second decade. A rapid generalization to other height stimuli and a chronic course of illness with at least moderate impairment were observed. A total of 22.5 % of individuals with vHI experienced the intensity of panic attacks. The lifetime prevalence of acrophobia was 6.4 % (women 8.6 %, men 4.1 %), and point prevalence was 2.0 % (women 2.8 %; men 1.1 %). VHI and even more acrophobia were associated with high rates of comorbid anxious and depressive conditions. Migraine was both a significant predictor of later acrophobia and a significant consequence of previous acrophobia. VHI affects nearly a third of the general population; in more than 20 % of these persons, vHI occasionally develops into panic attacks and in 6.4 %, it escalates to acrophobia. Symptoms and degree of social impairment form a continuum of mild to seriously distressing conditions in susceptible subjects. PMID:25262317

  4. Age mediation of frontoparietal activation during visual feature search.

    PubMed

    Madden, David J; Parks, Emily L; Davis, Simon W; Diaz, Michele T; Potter, Guy G; Chou, Ying-hui; Chen, Nan-kuei; Cabeza, Roberto

    2014-11-15

    Activation of frontal and parietal brain regions is associated with attentional control during visual search. We used fMRI to characterize age-related differences in frontoparietal activation in a highly efficient feature search task, detection of a shape singleton. On half of the trials, a salient distractor (a color singleton) was present in the display. The hypothesis was that frontoparietal activation mediated the relation between age and attentional capture by the salient distractor. Participants were healthy, community-dwelling individuals, 21 younger adults (19-29 years of age) and 21 older adults (60-87 years of age). Top-down attention, in the form of target predictability, was associated with an improvement in search performance that was comparable for younger and older adults. The increase in search reaction time (RT) associated with the salient distractor (attentional capture), standardized to correct for generalized age-related slowing, was greater for older adults than for younger adults. On trials with a color singleton distractor, search RT increased as a function of increasing activation in frontal regions, for both age groups combined, suggesting increased task difficulty. Mediational analyses disconfirmed the hypothesized model, in which frontal activation mediated the age-related increase in attentional capture, but supported an alternative model in which age was a mediator of the relation between frontal activation and capture. PMID:25102420

  5. Visual search strategy, selective attention, and expertise in soccer.

    PubMed

    Williams, A M; Davids, K

    1998-06-01

    This research examined the relationship between visual search strategy, selective attention, and expertise in soccer. Experienced (n = 12) and less experienced (n = 12) soccer players moved in response to filmed offensive sequences. Experiment 1 examined differences in search strategy between the two groups, using an eye movement registration system. Experienced players demonstrated superior anticipation in 3-on-3 and 1-on-1 soccer simulations. There were no differences in search strategy in 3-on-3 situations. In 1-on-1 simulations, the experienced players had a higher search rate, involving more fixations of shorter duration, and fixated for longer on the hip region, indicating that this area was important in anticipating an opponent's movements. Experiment 2 examined the relationship between visual fixation and selective attention, using a spatial occlusion approach. In 3-on-3 situations, masking information "pick up" from areas other than the ball or ball passer had a more detrimental effect on the experienced players' performances, suggesting differences in selective attention. In 1-on-1 situations, occluding an oncoming dribbler's head and shoulders, hips, or lower leg and ball region did not affect the experienced players' performances more than the less experienced group. The disparities in search strategy observed in Experiment 1 did not directly relate to differences in information extraction. Experiment 3 used concurrent verbal reports to indicate where participants extracted information from while viewing 3-on-3 sequences. Experienced players spent less time attending to the ball or ball passer and more time on other areas of the display. Findings highlight the advantages of integrating eye movements with more direct measures of selective attention. PMID:9635326

  6. A pyramidal neural network for visual pattern recognition.

    PubMed

    Phung, Son Lam; Bouzerdoum, Abdesselam

    2007-03-01

    In this paper, we propose a new neural architecture for classification of visual patterns that is motivated by the two concepts of image pyramids and local receptive fields. The new architecture, called pyramidal neural network (PyraNet), has a hierarchical structure with two types of processing layers: Pyramidal layers and one-dimensional (1-D) layers. In the new network, nonlinear two-dimensional (2-D) neurons are trained to perform both image feature extraction and dimensionality reduction. We present and analyze five training methods for PyraNet [gradient descent (GD), gradient descent with momentum, resilient back-propagation (RPROP), Polak-Ribiere conjugate gradient (CG), and Levenberg-Marquadrt (LM)] and two choices of error functions [mean-square-error (mse) and cross-entropy (CE)]. In this paper, we apply PyraNet to determine gender from a facial image, and compare its performance on the standard facial recognition technology (FERET) database with three classifiers: The convolutional neural network (NN), the k-nearest neighbor (k-NN), and the support vector machine (SVM). PMID:17385623

  7. Mouse Visual Neocortex Supports Multiple Stereotyped Patterns of Microcircuit Activity

    PubMed Central

    Sadovsky, Alexander J.

    2014-01-01

    Spiking correlations between neocortical neurons provide insight into the underlying synaptic connectivity that defines cortical microcircuitry. Here, using two-photon calcium fluorescence imaging, we observed the simultaneous dynamics of hundreds of neurons in slices of mouse primary visual cortex (V1). Consistent with a balance of excitation and inhibition, V1 dynamics were characterized by a linear scaling between firing rate and circuit size. Using lagged firing correlations between neurons, we generated functional wiring diagrams to evaluate the topological features of V1 microcircuitry. We found that circuit connectivity exhibited both cyclic graph motifs, indicating recurrent wiring, and acyclic graph motifs, indicating feedforward wiring. After overlaying the functional wiring diagrams onto the imaged field of view, we found properties consistent with Rentian scaling: wiring diagrams were topologically efficient because they minimized wiring with a modular architecture. Within single imaged fields of view, V1 contained multiple discrete circuits that were overlapping and highly interdigitated but were still distinct from one another. The majority of neurons that were shared between circuits displayed peri-event spiking activity whose timing was specific to the active circuit, whereas spike times for a smaller percentage of neurons were invariant to circuit identity. These data provide evidence that V1 microcircuitry exhibits balanced dynamics, is efficiently arranged in anatomical space, and is capable of supporting a diversity of multineuron spike firing patterns from overlapping sets of neurons. PMID:24899701

  8. Adaptation improves performance on a visual search task

    PubMed Central

    Wissig, Stephanie C.; Patterson, Carlyn A.; Kohn, Adam

    2013-01-01

    Temporal context, or adaptation, profoundly affects visual perception. Despite the strength and prevalence of adaptation effects, their functional role in visual processing remains unclear. The effects of spatial context and their functional role are better understood: these effects highlight features that differ from their surroundings and determine stimulus salience. Similarities in the perceptual and physiological effects of spatial and temporal context raise the possibility that they serve similar functions. We therefore tested the possibility that adaptation can enhance stimulus salience. We measured the effects of prolonged (40 s) adaptation to a counterphase grating on performance in a search task in which targets were defined by an orientation offset relative to a background of distracters. We found that, for targets with small orientation offsets, adaptation reduced reaction times and decreased the number of saccades made to find targets. Our results provide evidence that adaptation may function to highlight features that differ from the temporal context in which they are embedded. PMID:23390320

  9. Learning to Recognize Patterns: Changes in the Visual Field with Familiarity

    NASA Astrophysics Data System (ADS)

    Bebko, James M.; Uchikawa, Keiji; Saida, Shinya; Ikeda, Mitsuo

    1995-01-01

    Two studies were conducted to investigate changes which take place in the visual information processing of novel stimuli as they become familiar. Japanese writing characters (Hiragana and Kanji) which were unfamiliar to two native English speaking subjects were presented using a moving window technique to restrict their visual fields. Study time for visual recognition was recorded across repeated sessions, and with varying visual field restrictions. The critical visual field was defined as the size of the visual field beyond which further increases did not improve the speed of recognition performance. In the first study, when the Hiragana patterns were novel, subjects needed to see about half of the entire pattern simultaneously to maintain optimal performance. However, the critical visual field size decreased as familiarity with the patterns increased. These results were replicated in the second study with more complex Kanji characters. In addition, the critical field size decreased as pattern complexity decreased. We propose a three component model of pattern perception. In the first stage a representation of the stimulus must be constructed by the subject, and restricting of the visual field interferes dramatically with this component when stimuli are unfamiliar. With increased familiarity, subjects become able to reconstruct a previous representation from very small, unique segments of the pattern, analogous to the informativeness areas hypothesized by Loftus and Mackworth [J. Exp. Psychol., 4 (1978) 565].

  10. Task Specificity and the Influence of Memory on Visual Search: Comment on Vo and Wolfe (2012)

    ERIC Educational Resources Information Center

    Hollingworth, Andrew

    2012-01-01

    Recent results from Vo and Wolfe (2012b) suggest that the application of memory to visual search may be task specific: Previous experience searching for an object facilitated later search for that object, but object information acquired during a different task did not appear to transfer to search. The latter inference depended on evidence that a…

  11. VISUAL INTERFACE FOR THE CONCEPT DISTRIBUTION ANALYSIS IN VIDEO SEARCH RESULTS

    E-print Network

    Paris-Sud XI, Université de

    . Despite the current performance of the 'traditional' search engines, the video search engines.2 Indexation and Tagging 2.2.1 Tagging The method currently most used in search engines is the tagging (ChengVISUAL INTERFACE FOR THE CONCEPT DISTRIBUTION ANALYSIS IN VIDEO SEARCH RESULTS Multi

  12. Modeling and Visualization of Flower Color Patterns Department of Computer Science and Technology

    E-print Network

    Paris-Sud XI, Université de

    Modeling and Visualization of Flower Color Patterns Ning Zhou Department of Computer Science@mail.tsinghua.edu.cn Abstract Flowers are familiar in virtual scenes, however, the de- sign of flower patterns is still mainly done by hand. To produce a number of flower color patterns required by a large scene can be very labor

  13. Rapid resumption of interrupted search is independent of age-related improvements in visual search.

    PubMed

    Lleras, Alejandro; Porporino, Mafalda; Burack, Jacob A; Enns, James T

    2011-05-01

    In this study, 7-19-year-olds performed an interrupted visual search task in two experiments. Our question was whether the tendency to respond within 500ms after a second glimpse of a display (the rapid resumption effect [Psychological Science, 16 (2005) 684-688]) would increase with age in the same way as overall search efficiency. The results indicated no correlation of rapid resumption with search speed either across age groups (7, 9, 11, and 19years) or at the level of individual participants. Moreover, relocating the target randomly between looks reduced the rate of rapid resumption in a very similar way at each age. These results imply that implicit perceptual prediction during search is invariant across this age range and is distinct from other critical processes such as feature integration and control over spatial attention. PMID:21109252

  14. Neuropsychologia 44 (2006) 19621977 Visual search deficits in Parkinson's disease are attenuated by

    E-print Network

    Neuropsychologia 44 (2006) 1962­1977 Visual search deficits in Parkinson's disease are attenuated, exhibit deficits in selecting task-relevant stimuli in the presence of irrelevant stimuli, such as in visual search tasks. However, results from previous studies suggest that these deficits may vary

  15. Is There a Limit to the Superiority of Individuals with ASD in Visual Search?

    ERIC Educational Resources Information Center

    Hessels, Roy S.; Hooge, Ignace T. C.; Snijders, Tineke M.; Kemner, Chantal

    2014-01-01

    Superiority in visual search for individuals diagnosed with autism spectrum disorder (ASD) is a well-reported finding. We administered two visual search tasks to individuals with ASD and matched controls. One showed no difference between the groups, and one did show the expected superior performance for individuals with ASD. These results offer an…

  16. Parafoveal Retinal Vascular Response to Pattern Visual Stimulation Assessed with OCT Angiography

    E-print Network

    Wei, Eric

    We used optical coherence tomography (OCT) angiography with a high-speed swept-source OCT system to investigate retinal blood flow changes induced by visual stimulation with a reversing checkerboard pattern. The split-spectrum ...

  17. Aberrant Patterns of Visual Facial Information Usage in Schizophrenia Cameron M. Clark

    E-print Network

    Gosselin, Frédéric

    Aberrant Patterns of Visual Facial Information Usage in Schizophrenia Cameron M. Clark University emotion perception have been linked to poorer functional outcome in schizophrenia. However understand the nature of facial emotion perception deficits in schizophrenia, we used the Bubbles Facial

  18. Disruptive Body Patterning of Cuttlefish (Sepia officinalis) Requires Visual Information Regarding

    E-print Network

    Hanlon, Roger T.

    Disruptive Body Patterning of Cuttlefish (Sepia officinalis) Requires Visual Information Regarding of Sussex, Brighton, UK Cuttlefish (Sepia officinalis Linnaeus, 1758) on mixed light and dark gravel show of natural substrates that cuttlefish cue on visually are largely unknown. Therefore, we aimed to identify

  19. Visual Working Memory Supports the Inhibition of Previously Processed Information: Evidence from Preview Search

    ERIC Educational Resources Information Center

    Al-Aidroos, Naseem; Emrich, Stephen M.; Ferber, Susanne; Pratt, Jay

    2012-01-01

    In four experiments we assessed whether visual working memory (VWM) maintains a record of previously processed visual information, allowing old information to be inhibited, and new information to be prioritized. Specifically, we evaluated whether VWM contributes to the inhibition (i.e., visual marking) of previewed distractors in a preview search.…

  20. Bicycle accidents and drivers' visual search at left and right turns.

    PubMed

    Summala, H; Pasanen, E; Räsänen, M; Sievänen, J

    1996-03-01

    The accident data base of the City of Helsinki shows that when drivers cross a cycle path as they enter a non-signalized intersection, the clearly dominant type of car-cycle crashes is that in which a cyclist comes from the right and the driver is turning right, in marked contrast to the cases with drivers turning left (Pasanen 1992; City of Helsinki, Traffic Planning Department, Report L4). This study first tested an explanation that drivers turning right simply focus their attention on the cars coming from the left-those coming from the right posing no threat to them-and fail to see the cyclist from the right early enough. Drivers' scanning behavior was studied at two T-intersections. Two well-hidden video cameras were used, one to measure the head movements of the approaching drivers and the other one to measure speed and distance from the cycle crossroad. The results supported the hypothesis: the drivers turning right scanned the right leg of the T-intersection less frequently and later than those turning left. Thus, it appears that drivers develop a visual scanning strategy which concentrates on detection of more frequent and major dangers but ignores and may even mask visual information on less frequent dangers. The second part of the study evaluated different countermeasures, including speed humps, in terms of drivers' visual search behavior. The results suggested that speed-reducing countermeasures changed drivers' visual search patterns in favor of the cyclists coming from the right, presumably at least in part due to the fact that drivers were simply provided with more time to focus on each direction. PMID:8703272

  1. Strategies of the honeybee Apis mellifera during visual search for vertical targets presented at various heights: a role for spatial attention?

    PubMed Central

    Morawetz, Linde; Chittka, Lars; Spaethe, Johannes

    2014-01-01

    When honeybees are presented with a colour discrimination task, they tend to choose swiftly and accurately when objects are presented in the ventral part of their frontal visual field. In contrast, poor performance is observed when objects appear in the dorsal part. Here we investigate if this asymmetry is caused by fixed search patterns or if bees can use alternative search mechanisms such as spatial attention, which allows flexible focusing on different areas of the visual field. We asked individual honeybees to choose an orange rewarded target among blue distractors. Target and distractors were presented in the ventral visual field, the dorsal field or both. Bees presented with targets in the ventral visual field consistently had the highest search efficiency, with rapid decisions, high accuracy and direct flight paths. In contrast, search performance for dorsally located targets was inaccurate and slow at the beginning of the test phase, but bees increased their search performance significantly after a few learning trials: they found the target faster, made fewer errors and flew in a straight line towards the target. However, bees needed thrice as long to improve the search for a dorsally located target when the target’s position changed randomly between the ventral and the dorsal visual field. We propose that honeybees form expectations of the location of the target’s appearance and adapt their search strategy accordingly. Different possible mechanisms of this behavioural adaptation are discussed. PMID:25254109

  2. Relationships among balance, visual search, and lacrosse-shot accuracy.

    PubMed

    Marsh, Darrin W; Richard, Leon A; Verre, Arlene B; Myers, Jay

    2010-06-01

    The purpose of this study was to examine variables that may contribute to shot accuracy in women's college lacrosse. A convenience sample of 15 healthy women's National Collegiate Athletic Association Division III College lacrosse players aged 18-23 (mean+/-SD, 20.27+/-1.67) participated in the study. Four experimental variables were examined: balance, visual search, hand grip strength, and shoulder joint position sense. Balance was measured by the Biodex Stability System (BSS), and visual search was measured by the Trail-Making Test Part A (TMTA) and Trail-Making Test Part B (TMTB). Hand-grip strength was measured by a standard hand dynamometer, and shoulder joint position sense was measured using a modified inclinometer. All measures were taken in an indoor setting. These experimental variables were then compared with lacrosse-shot error that was measured indoors using a high-speed video camera recorder and a specialized L-shaped apparatus. A Stalker radar gun measured lacrosse-shot velocity. The mean lacrosse-shot error was 15.17 cm with a mean lacrosse-shot velocity of 17.14 m.s (38.35 mph). Lower scores on the BSS level 8 eyes open (BSS L8 E/O) test and TMTB were positively related to less lacrosse-shot error (r=0.760, p=0.011) and (r=0.519, p=0.048), respectively. Relations were not significant between lacrosse-shot error and grip strength (r=0.191, p = 0.496), lacrosse-shot error and BSS level 8 eyes closed (BSS L8 E/C) (r=0.501, p=0.102), lacrosse-shot error and BSS level 4 eyes open (BSS L4 E/O) (r=0.313, p=0.378), lacrosse-shot error and BSS level 4 eyes closed (BSS L4 E/C) (r=-0.029, p=0.936) lacrosse-shot error and shoulder joint position sense (r=-0.509, p=0.055) and between lacrosse-shot error and TMTA (r=0.375, p=0.168). The results reveal that greater levels of shot accuracy may be related to greater levels of visual search and balance ability in women college lacrosse athletes. PMID:20508452

  3. Visual-auditory integration for visual search: a behavioral study in barn owls.

    PubMed

    Hazan, Yael; Kra, Yonatan; Yarin, Inna; Wagner, Hermann; Gutfreund, Yoram

    2015-01-01

    Barn owls are nocturnal predators that rely on both vision and hearing for survival. The optic tectum of barn owls, a midbrain structure involved in selective attention, has been used as a model for studying visual-auditory integration at the neuronal level. However, behavioral data on visual-auditory integration in barn owls are lacking. The goal of this study was to examine if the integration of visual and auditory signals contributes to the process of guiding attention toward salient stimuli. We attached miniature wireless video cameras on barn owls' heads (OwlCam) to track their target of gaze. We first provide evidence that the area centralis (a retinal area with a maximal density of photoreceptors) is used as a functional fovea in barn owls. Thus, by mapping the projection of the area centralis on the OwlCam's video frame, it is possible to extract the target of gaze. For the experiment, owls were positioned on a high perch and four food items were scattered in a large arena on the floor. In addition, a hidden loudspeaker was positioned in the arena. The positions of the food items and speaker were changed every session. Video sequences from the OwlCam were saved for offline analysis while the owls spontaneously scanned the room and the food items with abrupt gaze shifts (head saccades). From time to time during the experiment, a brief sound was emitted from the speaker. The fixation points immediately following the sounds were extracted and the distances between the gaze position and the nearest items and loudspeaker were measured. The head saccades were rarely toward the location of the sound source but to salient visual features in the room, such as the door knob or the food items. However, among the food items, the one closest to the loudspeaker had the highest probability of attracting a gaze shift. This result supports the notion that auditory signals are integrated with visual information for the selection of the next visual search target. PMID:25762905

  4. Visual-auditory integration for visual search: a behavioral study in barn owls

    PubMed Central

    Hazan, Yael; Kra, Yonatan; Yarin, Inna; Wagner, Hermann; Gutfreund, Yoram

    2015-01-01

    Barn owls are nocturnal predators that rely on both vision and hearing for survival. The optic tectum of barn owls, a midbrain structure involved in selective attention, has been used as a model for studying visual-auditory integration at the neuronal level. However, behavioral data on visual-auditory integration in barn owls are lacking. The goal of this study was to examine if the integration of visual and auditory signals contributes to the process of guiding attention toward salient stimuli. We attached miniature wireless video cameras on barn owls’ heads (OwlCam) to track their target of gaze. We first provide evidence that the area centralis (a retinal area with a maximal density of photoreceptors) is used as a functional fovea in barn owls. Thus, by mapping the projection of the area centralis on the OwlCam’s video frame, it is possible to extract the target of gaze. For the experiment, owls were positioned on a high perch and four food items were scattered in a large arena on the floor. In addition, a hidden loudspeaker was positioned in the arena. The positions of the food items and speaker were changed every session. Video sequences from the OwlCam were saved for offline analysis while the owls spontaneously scanned the room and the food items with abrupt gaze shifts (head saccades). From time to time during the experiment, a brief sound was emitted from the speaker. The fixation points immediately following the sounds were extracted and the distances between the gaze position and the nearest items and loudspeaker were measured. The head saccades were rarely toward the location of the sound source but to salient visual features in the room, such as the door knob or the food items. However, among the food items, the one closest to the loudspeaker had the highest probability of attracting a gaze shift. This result supports the notion that auditory signals are integrated with visual information for the selection of the next visual search target.

  5. EVALUATION OF A VISUALLY CATEGORIZED SEARCH ENGINE Berrin Dogusoy, Kursat Cagiltay

    E-print Network

    Paris-Sud XI, Université de

    EVALUATION OF A VISUALLY CATEGORIZED SEARCH ENGINE Berrin Dogusoy, Kursat Cagiltay Department and the search engines are becoming an indispensable tool in order to find information in Internet. While web, the intensive workload requires that people should use the time properly. Using search engines effectively turns

  6. Visual Intelligence: Using the Deep Patterns of Visual Language to Build Cognitive Skills

    ERIC Educational Resources Information Center

    Sibbet, David

    2008-01-01

    Thirty years of work as a graphic facilitator listening visually to people in every kind of organization has convinced the author that visual intelligence is a key to navigating an information economy rich with multimedia. He also believes that theory and disciplines developed by practitioners in this new field hold special promise for educators…

  7. Case role filling as a side effect of visual search

    SciTech Connect

    Marburger, H.; Wahlster, W.

    1983-01-01

    This paper addresses the problem of generating communicatively adequate extended responses in the absence of specific knowledge concerning the intentions of the questioner. The authors formulate and justify a heuristic for the selection of optional deep case slots not contained in the question as candidates for the additional information contained in an extended response. It is shown that, in a visually present domain of discourse, case role filling for the construction of an extended response can be regarded as a side effect of the visual search necessary to answer a question containing a locomotion verb. The paper describes the various representation constructions used in the German language dialog system HAM-ANS for dealing with the semantics of locomotion verbs and illustrates their use in generating extended responses. In particular, it outlines the structure of the geometrical scene description, the representation of events in a logic-oriented semantic representation language, the case-frame lexicon and the representation of the referential semantics based on the flavor system. The emphasis is on a detailed presentation of the application of object-oriented programming methods for coping with the semantics of locomotion verbs. The process of generating an extended response is illustrated by an extensively annotated trace. 13 references.

  8. A Pattern Search Filter Method for Nonlinear Programming without Derivatives

    Microsoft Academic Search

    Charles Audet; J. E. Dennis

    2004-01-01

    This paper formulates and analyzes a pattern search method for general constrained optimization based on filter methods for step acceptance. Roughly, a filter method accepts a step that either improves the objec- tive function value or the value of some function that measures the constraint violation. The new algorithm does not compute or approximate any derivatives, penalty constants or Lagrange

  9. Searching for Concurrent Design Patterns in Video Games

    E-print Network

    Fedorova, Alexandra

    Searching for Concurrent Design Patterns in Video Games Micah J Best1 , Alexandra Fedorova1 , Ryan, most existing video game engines are essentially sequential and thus cannot easily take ad- vantage-source video game Cube 2. We analyze the structure and unique requirements of this complex applica- tion domain

  10. Query suggestions for mobile search: understanding usage patterns

    Microsoft Academic Search

    Maryam Kamvar; Shumeet Baluja

    2008-01-01

    Entering search terms on mobile phones is a time consuming and cumbersome task. In this paper, we explore the usage patterns of query entry interfaces that display suggestions. Our primary goal is to build a usage model of query suggestions in order to provide user interface guidelines for mobile text prediction interfaces. We find that users who were asked to

  11. Prediction of shot success for basketball free throws: visual search strategy.

    PubMed

    Uchida, Yusuke; Mizuguchi, Nobuaki; Honda, Masaaki; Kanosue, Kazuyuki

    2014-01-01

    In ball games, players have to pay close attention to visual information in order to predict the movements of both the opponents and the ball. Previous studies have indicated that players primarily utilise cues concerning the ball and opponents' body motion. The information acquired must be effective for observing players to select the subsequent action. The present study evaluated the effects of changes in the video replay speed on the spatial visual search strategy and ability to predict free throw success. We compared eye movements made while observing a basketball free throw by novices and experienced basketball players. Correct response rates were close to chance (50%) at all video speeds for the novices. The correct response rate of experienced players was significantly above chance (and significantly above that of the novices) at the normal speed, but was not different from chance at both slow and fast speeds. Experienced players gazed more on the lower part of the player's body when viewing a normal speed video than the novices. The players likely detected critical visual information to predict shot success by properly moving their gaze according to the shooter's movements. This pattern did not change when the video speed was decreased, but changed when it was increased. These findings suggest that temporal information is important for predicting action outcomes and that such outcomes are sensitive to video speed. PMID:24319995

  12. RF antenna-pattern visual aids for field use

    NASA Technical Reports Server (NTRS)

    Williams, J. H.

    1973-01-01

    Series of plots must be made of antenna pattern on polar-coordinate sheet depicting vertical planes. Separate sheets are plotted depicting antenna patterns in vertical plane at azimuth positions. After all polar plots are drawn, they are labeled according to their azimuthal positions. Transparencies are then stiffened with regular wire, cardboard, or molded plastic.

  13. 1 Introduction In visual search tasks, observers typically look for a target item in a display with

    E-print Network

    search through visual displays. DOI:10.1068/p3414 #12;the relevant features are the terminators on the C1 Introduction In visual search tasks, observers typically look for a target item in a display of the efficiency of search (or of the cost of adding a distractor). In some cases, search is very efficient

  14. Finding an emotional face in a crowd: Emotional and perceptual stimulus factors influence visual search efficiency.

    PubMed

    Lundqvist, Daniel; Bruce, Neil; Öhman, Arne

    2015-06-01

    In this article, we examine how emotional and perceptual stimulus factors influence visual search efficiency. In an initial task, we run a visual search task, using a large number of target/distractor emotion combinations. In two subsequent tasks, we then assess measures of perceptual (rated and computational distances) and emotional (rated valence, arousal and potency) stimulus properties. In a series of regression analyses, we then explore the degree to which target salience (the size of target/distractor dissimilarities) on these emotional and perceptual measures predict the outcome on search efficiency measures (response times and accuracy) from the visual search task. The results show that both emotional and perceptual stimulus salience contribute to visual search efficiency. The results show that among the emotional measures, salience on arousal measures was more influential than valence salience. The importance of the arousal factor may be a contributing factor to contradictory history of results within this field. PMID:24933527

  15. Visual cluster analysis and pattern recognition template and methods

    DOEpatents

    Osbourn, Gordon Cecil (Albuquerque, NM); Martinez, Rubel Francisco (Albuquerque, NM)

    1999-01-01

    A method of clustering using a novel template to define a region of influence. Using neighboring approximation methods, computation times can be significantly reduced. The template and method are applicable and improve pattern recognition techniques.

  16. Visual cluster analysis and pattern recognition template and methods

    DOEpatents

    Osbourn, G.C.; Martinez, R.F.

    1999-05-04

    A method of clustering using a novel template to define a region of influence is disclosed. Using neighboring approximation methods, computation times can be significantly reduced. The template and method are applicable and improve pattern recognition techniques. 30 figs.

  17. Hypothesis Support Mechanism for Mid-Level Visual Pattern Recognition

    NASA Technical Reports Server (NTRS)

    Amador, Jose J (Inventor)

    2007-01-01

    A method of mid-level pattern recognition provides for a pose invariant Hough Transform by parametrizing pairs of points in a pattern with respect to at least two reference points, thereby providing a parameter table that is scale- or rotation-invariant. A corresponding inverse transform may be applied to test hypothesized matches in an image and a distance transform utilized to quantify the level of match.

  18. Visualization and analysis of 3D gene expression patterns in zebrafish using web services

    NASA Astrophysics Data System (ADS)

    Potikanond, D.; Verbeek, F. J.

    2012-01-01

    The analysis of patterns of gene expression patterns analysis plays an important role in developmental biology and molecular genetics. Visualizing both quantitative and spatio-temporal aspects of gene expression patterns together with referenced anatomical structures of a model-organism in 3D can help identifying how a group of genes are expressed at a certain location at a particular developmental stage of an organism. In this paper, we present an approach to provide an online visualization of gene expression data in zebrafish (Danio rerio) within 3D reconstruction model of zebrafish in different developmental stages. We developed web services that provide programmable access to the 3D reconstruction data and spatial-temporal gene expression data maintained in our local repositories. To demonstrate this work, we develop a web application that uses these web services to retrieve data from our local information systems. The web application also retrieve relevant analysis of microarray gene expression data from an external community resource; i.e. the ArrayExpress Atlas. All the relevant gene expression patterns data are subsequently integrated with the reconstruction data of the zebrafish atlas using ontology based mapping. The resulting visualization provides quantitative and spatial information on patterns of gene expression in a 3D graphical representation of the zebrafish atlas in a certain developmental stage. To deliver the visualization to the user, we developed a Java based 3D viewer client that can be integrated in a web interface allowing the user to visualize the integrated information over the Internet.

  19. ON THE LOCAL CONVERGENCE OF PATTERN SEARCH ELIZABETH D. DOLAN, ROBERT MICHAEL LEWIS, AND VIRGINIA TORCZON

    E-print Network

    Torczon, Virginia

    ON THE LOCAL CONVERGENCE OF PATTERN SEARCH ELIZABETH D. DOLAN, ROBERT MICHAEL LEWIS, AND VIRGINIA TORCZON Abstract. We examine the local convergence properties of pattern search methods, comple- menting-length control parameter which appears in the definition of pattern search al- gorithms provides a reliable

  20. ON THE LOCAL CONVERGENCE OF PATTERN SEARCH ELIZABETH D. DOLAN, ROBERT MICHAEL LEWIS, AND VIRGINIA TORCZON

    E-print Network

    Lewis, Robert Michael

    ON THE LOCAL CONVERGENCE OF PATTERN SEARCH ELIZABETH D. DOLAN, ROBERT MICHAEL LEWIS, AND VIRGINIA­583 Abstract. We examine the local convergence properties of pattern search methods, comple- menting-length control parameter which appears in the definition of pattern search al- gorithms provides a reliable

  1. Dementia alters standing postural adaptation during a visual search task in older adult men.

    PubMed

    Jor'dan, Azizah J; McCarten, J Riley; Rottunda, Susan; Stoffregen, Thomas A; Manor, Brad; Wade, Michael G

    2015-04-23

    This study investigated the effects of dementia on standing postural adaptation during performance of a visual search task. We recruited 16 older adults with dementia and 15 without dementia. Postural sway was assessed by recording medial-lateral (ML) and anterior-posterior (AP) center-of-pressure when standing with and without a visual search task; i.e., counting target letter frequency within a block of displayed randomized letters. ML sway variability was significantly higher in those with dementia during visual search as compared to those without dementia and compared to both groups during the control condition. AP sway variability was significantly greater in those with dementia as compared to those without dementia, irrespective of task condition. In the ML direction, the absolute and percent change in sway variability between the control condition and visual search (i.e., postural adaptation) was greater in those with dementia as compared to those without. In contrast, postural adaptation to visual search was similar between groups in the AP direction. As compared to those without dementia, those with dementia identified fewer letters on the visual task. In the non-dementia group only, greater increases in postural adaptation in both the ML and AP direction, correlated with lower performance on the visual task. The observed relationship between postural adaptation during the visual search task and visual search task performance-in the non-dementia group only-suggests a critical link between perception and action. Dementia reduces the capacity to perform a visual-based task while standing and thus, appears to disrupt this perception-action synergy. PMID:25770830

  2. Investigating the role of visual and auditory search in reading and developmental dyslexia

    PubMed Central

    Lallier, Marie; Donnadieu, Sophie; Valdois, Sylviane

    2013-01-01

    It has been suggested that auditory and visual sequential processing deficits contribute to phonological disorders in developmental dyslexia. As an alternative explanation to a phonological deficit as the proximal cause for reading disorders, the visual attention span hypothesis (VA Span) suggests that difficulties in processing visual elements simultaneously lead to dyslexia, regardless of the presence of a phonological disorder. In this study, we assessed whether deficits in processing simultaneously displayed visual or auditory elements is linked to dyslexia associated with a VA Span impairment. Sixteen children with developmental dyslexia and 16 age-matched skilled readers were assessed on visual and auditory search tasks. Participants were asked to detect a target presented simultaneously with 3, 9, or 15 distracters. In the visual modality, target detection was slower in the dyslexic children than in the control group on a “serial” search condition only: the intercepts (but not the slopes) of the search functions were higher in the dyslexic group than in the control group. In the auditory modality, although no group difference was observed, search performance was influenced by the number of distracters in the control group only. Within the dyslexic group, not only poor visual search (high reaction times and intercepts) but also low auditory search performance (d?) strongly correlated with poor irregular word reading accuracy. Moreover, both visual and auditory search performance was associated with the VA Span abilities of dyslexic participants but not with their phonological skills. The present data suggests that some visual mechanisms engaged in “serial” search contribute to reading and orthographic knowledge via VA Span skills regardless of phonological skills. The present results further open the question of the role of auditory simultaneous processing in reading as well as its link with VA Span skills. PMID:24093014

  3. Why is visual search superior in autism spectrum disorder? Robert M. Joseph,1

    E-print Network

    PAPER Why is visual search superior in autism spectrum disorder? Robert M. Joseph,1 Brandon Keehn,1, van Ewijk, van Engeland & Hooge, 2008; O'Riordan & Plaisted, 2001; O'Riordan, Plaisted, Driver & Baron

  4. What are the shapes of response time distributions in visual search?

    E-print Network

    Palmer, Evan M.

    Many visual search experiments measure response time (RT) as their primary dependent variable. Analyses typically focus on mean (or median) RT. However, given enough data, the RT distribution can be a rich source of ...

  5. The NLP Swish Pattern: An Innovative Visualizing Technique.

    ERIC Educational Resources Information Center

    Masters, Betsy J.; And Others

    1991-01-01

    Describes swish pattern, one of many innovative therapeutic interventions that developers of neurolinguistic programing (NLP) have contributed to counseling profession. Presents brief overview of NLP followed by an explanation of the basic theory and expected outcomes of the swish. Presents description of the intervention process and case studies…

  6. PATTERN REVERSAL VISUAL EVOKED POTENTIALS IN AWAKE RATS

    EPA Science Inventory

    A method for recording pattern reversal evoked potentials (PREPs) from awake restrained rats has been developed. The procedure of Onofrj et al. was modified to eliminate the need for anesthetic, thereby avoiding possible interactions of the anesthetic with other manipulations of ...

  7. Levels of feature analysis in processing visual patterns.

    PubMed

    Ward, L M; Wexler, D A

    1976-01-01

    In this paper, a revised Pandemonium-like model of visual-feature processing is formulated and a preliminary test of its feasibility is reported. The model differentiates visual-feature processing into a series of hierarchical stages organized by increasing complexity, with the output of each stage going both to the next higher stage, and directly to a more central processor. In the experiment, subjects sorted decks of cards into piles according to the presence or absence of a target stimulus which differed from nontargets in a variety of different features; detection of a feature was sufficient for detection of a target. The data generally supported the revised Pandemonium model, in that targets which differed from nontargets in features thought to be low in the hierarchy were processed faster than targets whose difference was in a high level feature. An extension of the revised model did somewhat less well in predicting the results of sorting for targets in which detection of any one of several features was sufficient for target detection. PMID:1005018

  8. Use of a twin dataset to identify AMD-related visual patterns controlled by genetic factors

    NASA Astrophysics Data System (ADS)

    Quellec, Gwénolé; Abràmoff, Michael D.; Russell, Stephen R.

    2010-03-01

    The mapping of genotype to the phenotype of age-related macular degeneration (AMD) is expected to improve the diagnosis and treatment of the disease in a near future. In this study, we focused on the first step to discover this mapping: we identified visual patterns related to AMD which seem to be controlled by genetic factors, without explicitly relating them to the genes. For this purpose, we used a dataset of eye fundus photographs from 74 twin pairs, either monozygotic twins, who have the same genotype, or dizygotic twins, whose genes responsible for AMD are less likely to be identical. If we are able to differentiate monozygotic twins from dizygotic twins, based on a given visual pattern, then this pattern is likely to be controlled by genetic factors. The main visible consequence of AMD is the apparition of drusen between the retinal pigment epithelium and Bruch's membrane. We developed two automated drusen detectors based on the wavelet transform: a shape-based detector for hard drusen, and a texture- and color- based detector for soft drusen. Forty visual features were evaluated at the location of the automatically detected drusen. These features characterize the texture, the shape, the color, the spatial distribution, or the amount of drusen. A distance measure between twin pairs was defined for each visual feature; a smaller distance should be measured between monozygotic twins for visual features controlled by genetic factors. The predictions of several visual features (75.7% accuracy) are comparable or better than the predictions of human experts.

  9. Multimodal signals: enhancement and constraint of song motor patterns by visual display.

    PubMed

    Cooper, Brenton G; Goller, Franz

    2004-01-23

    Many birds perform visual signals during their learned songs, but little is known about the interrelationship between visual and vocal displays. We show here that male brown-headed cowbirds (Molothrus ater) synchronize the most elaborate wing movements of their display with atypically long silent periods in their song, potentially avoiding adverse biomechanical effects on sound production. Furthermore, expiratory effort for song is significantly reduced when cowbirds perform their wing display. These results show a close integration between vocal and visual displays and suggest that constraints and synergistic interactions between the motor patterns of multimodal signals influence the evolution of birdsong. PMID:14739462

  10. The effects of task difficulty on visual search strategy in virtual 3D displays

    PubMed Central

    Pomplun, Marc; Garaas, Tyler W.; Carrasco, Marisa

    2013-01-01

    Analyzing the factors that determine our choice of visual search strategy may shed light on visual behavior in everyday situations. Previous results suggest that increasing task difficulty leads to more systematic search paths. Here we analyze observers' eye movements in an “easy” conjunction search task and a “difficult” shape search task to study visual search strategies in stereoscopic search displays with virtual depth induced by binocular disparity. Standard eye-movement variables, such as fixation duration and initial saccade latency, as well as new measures proposed here, such as saccadic step size, relative saccadic selectivity, and x?y target distance, revealed systematic effects on search dynamics in the horizontal-vertical plane throughout the search process. We found that in the “easy” task, observers start with the processing of display items in the display center immediately after stimulus onset and subsequently move their gaze outwards, guided by extrafoveally perceived stimulus color. In contrast, the “difficult” task induced an initial gaze shift to the upper-left display corner, followed by a systematic left-right and top-down search process. The only consistent depth effect was a trend of initial saccades in the easy task with smallest displays to the items closest to the observer. The results demonstrate the utility of eye-movement analysis for understanding search strategies and provide a first step toward studying search strategies in actual 3D scenarios. PMID:23986539

  11. System reconfiguration, not resource depletion, determines the efficiency of visual search

    Microsoft Academic Search

    Vincent Di Lollo; Daniel Smilek; Jun-Ichiro Kawahara; S. M. Shahab Ghorashi

    2005-01-01

    We examined two theories of visual search: resource depletion, grounded in a static, built-in brain architecture, with attention\\u000a seen as a limited depletable resource, and system reconfiguration, in which the visual system is dynamically reconfigured\\u000a from moment to moment so as to optimize performance on the task at hand. In a dual-task paradigm, a search display was preceded\\u000a by a

  12. Graph Use to Visualize Web Search Results: MyWish 3.0

    Microsoft Academic Search

    Michele Angelaccio; Berta Buttarazzi; M. Patrignanelli

    2007-01-01

    This work suggests a search tool, MyWISH 3.0, as a solution for common web search results visualization limits. This tool unifies performance standards of a stable tool with the advanced visualization ability of a Java-based, highly configurable component. The data flow of these two modules ends up in an XML interface. Moreover, because of its accurate caching techniques and its

  13. Exploiting visual search theory to infer social interactions

    NASA Astrophysics Data System (ADS)

    Rota, Paolo; Dang-Nguyen, Duc-Tien; Conci, Nicola; Sebe, Nicu

    2013-03-01

    In this paper we propose a new method to infer human social interactions using typical techniques adopted in literature for visual search and information retrieval. The main piece of information we use to discriminate among different types of interactions is provided by proxemics cues acquired by a tracker, and used to distinguish between intentional and casual interactions. The proxemics information has been acquired through the analysis of two different metrics: on the one hand we observe the current distance between subjects, and on the other hand we measure the O-space synergy between subjects. The obtained values are taken at every time step over a temporal sliding window, and processed in the Discrete Fourier Transform (DFT) domain. The features are eventually merged into an unique array, and clustered using the K-means algorithm. The clusters are reorganized using a second larger temporal window into a Bag Of Words framework, so as to build the feature vector that will feed the SVM classifier.

  14. Patterned-String Tasks: Relation between Fine Motor Skills and Visual-Spatial Abilities in Parrots

    PubMed Central

    Krasheninnikova, Anastasia

    2013-01-01

    String-pulling and patterned-string tasks are often used to analyse perceptual and cognitive abilities in animals. In addition, the paradigm can be used to test the interrelation between visual-spatial and motor performance. Two Australian parrot species, the galah (Eolophus roseicapilla) and the cockatiel (Nymphicus hollandicus), forage on the ground, but only the galah uses its feet to manipulate food. I used a set of string pulling and patterned-string tasks to test whether usage of the feet during foraging is a prerequisite for solving the vertical string pulling problem. Indeed, the two species used techniques that clearly differed in the extent of beak-foot coordination but did not differ in terms of their success in solving the string pulling task. However, when the visual-spatial skills of the subjects were tested, the galahs outperformed the cockatiels. This supports the hypothesis that the fine motor skills needed for advanced beak-foot coordination may be interrelated with certain visual-spatial abilities needed for solving patterned-string tasks. This pattern was also found within each of the two species on the individual level: higher motor abilities positively correlated with performance in patterned-string tasks. This is the first evidence of an interrelation between visual-spatial and motor abilities in non-mammalian animals. PMID:24376885

  15. A Bio-inspired Architecture of an Active Visual Search Model

    Microsoft Academic Search

    Vassilis Cutsuridis

    2008-01-01

    A novel brain inspired cognitive system architecture of an active visual search model is presented. The model is multi-modular consisting of spatial and object visual processing, attention, reinforce- ment learning, motor plan and motor execution modules. The novelty of the model lies on its decision making mechanisms. In contrast to previ- ous models, decisions are made from the interplay of

  16. The Role of Target-Distractor Relationships in Guiding Attention and the Eyes in Visual Search

    ERIC Educational Resources Information Center

    Becker, Stefanie I.

    2010-01-01

    Current models of visual search assume that visual attention can be guided by tuning attention toward specific feature values (e.g., particular size, color) or by inhibiting the features of the irrelevant nontargets. The present study demonstrates that attention and eye movements can also be guided by a relational specification of how the target…

  17. Detection of Emotional Faces: Salient Physical Features Guide Effective Visual Search

    ERIC Educational Resources Information Center

    Calvo, Manuel G.; Nummenmaa, Lauri

    2008-01-01

    In this study, the authors investigated how salient visual features capture attention and facilitate detection of emotional facial expressions. In a visual search task, a target emotional face (happy, disgusted, fearful, angry, sad, or surprised) was presented in an array of neutral faces. Faster detection of happy and, to a lesser extent,…

  18. Visualizing temporal patterns of demand, throughput and crowding in an emergency department.

    PubMed

    Calvitti, Alan; Hoot, Nathan

    2007-01-01

    Emergency department (ED) operational data were calculated at 10-minute intervals throughout 2006 (n = 52561) in the adult ED of an academic medical center. Several operational parameters per observation were measured to better understand temporal patterns of input, throughput, and output of medical services. This may allow for improvement of predictive models of overcrowding. Visualization of this dataset is structured by a calendar template, facilitating discovery of cyclic patterns at diurnal, weekly, and monthly scales. PMID:18693989

  19. Contextual Cueing in Multiconjunction Visual Search Is Dependent on Color- and Configuration-Based Intertrial Contingencies

    ERIC Educational Resources Information Center

    Geyer, Thomas; Shi, Zhuanghua; Muller, Hermann J.

    2010-01-01

    Three experiments examined memory-based guidance of visual search using a modified version of the contextual-cueing paradigm (Jiang & Chun, 2001). The target, if present, was a conjunction of color and orientation, with target (and distractor) features randomly varying across trials (multiconjunction search). Under these conditions, reaction times…

  20. Transformation of an Uncertain Video Search Pipeline to a Sketch-based Visual Analytics Loop

    E-print Network

    Jones, Mark W.

    Transformation of an Uncertain Video Search Pipeline to a Sketch-based Visual Analytics Loop Philip Chen Abstract-- Traditional sketch-based image or video search systems rely on machine learning since videos may not be semantically annotated sufficiently, there may be a lack of suitable training

  1. Cortical Dynamics of Contextually Cued Attentive Visual Learning and Search: Spatial and Object Evidence Accumulation

    ERIC Educational Resources Information Center

    Huang, Tsung-Ren; Grossberg, Stephen

    2010-01-01

    How do humans use target-predictive contextual information to facilitate visual search? How are consistently paired scenic objects and positions learned and used to more efficiently guide search in familiar scenes? For example, humans can learn that a certain combination of objects may define a context for a kitchen and trigger a more efficient…

  2. 3D pattern of brain abnormalities in Williams syndrome visualized using tensor-based morphometry

    E-print Network

    Bellugi, Ursula

    3D pattern of brain abnormalities in Williams syndrome visualized using tensor-based morphometry Williams syndrome (WS) is a neurodevelopmental disorder associated with deletion of 20 contiguous genes reserved. Introduction Williams syndrome (WS) is a neurodevelopmental microdele- tion disorder, resulting

  3. Visualizing and Discovering Web Navigational Patterns Jiyang Chen, Lisheng Sun, Osmar R. Zaiane, Randy Goebel

    E-print Network

    Zaiane, Osmar R.

    Visualizing and Discovering Web Navigational Patterns Jiyang Chen, Lisheng Sun, Osmar R. Za, lisheng, zaiane, goebel}@cs.ualberta.ca ABSTRACT Web site structures are complex to analyze. Cross-referencing the web structure with navigational behaviour adds to the complexity of the analysis. However

  4. Discovering interesting usage patterns in text collections: integrating text mining with visualization

    Microsoft Academic Search

    Anthony Don; Elena Zheleva; Machon Gregory; Sureyya Tarkan; Loretta Auvil; Tanya Clement; Ben Shneiderman; Catherine Plaisant

    2007-01-01

    This paper addresses the problem of making text mining results more comprehensible to humanities scholars, journalists, intelligence analysts, and other researchers, in order to support the analysis of text collections. Our system, FeatureLens, visualizes a text collection at several levels of granularity and enables users to explore interesting text patterns. The current implementation focuses on frequent itemsets of n-grams, as

  5. Effects of Food Deprivation and Olfactory and Visual Cues on Movement Patterns of Two Eleodes Species

    E-print Network

    McIntyre, Nancy E.

    they orient to food by means of vision, olfaction, or both. Hunger affected foraging behavior with respectBEHAVIOR Effects of Food Deprivation and Olfactory and Visual Cues on Movement Patterns of Two-deprived and fed individuals did not significantly differ, indicating that food deprivation affects the ethological

  6. Advances in the Use of Neurophysiologycally-based Fusion for Visualization and Pattern Recognition of

    E-print Network

    Wang, Xiaorui "Ray"

    .e. MRI, CT, PET, SPECT, etc.). By providing a single fused image, this architecture can increase userAdvances in the Use of Neurophysiologycally-based Fusion for Visualization and Pattern Recognition and information maximization. To this end, we have improved on an image fusion architecture first developed

  7. Fault diagnosis of internal combustion engines using visual dot patterns of acoustic and vibration signals

    Microsoft Academic Search

    Jian-Da Wu; Chao-Qin Chuang

    2005-01-01

    An investigation of the fault diagnosis technique in internal combustion engines based on the visual dot pattern of acoustic and vibration signals is presented in this paper. Acoustic emissions and vibration signals are well known as being able to be used for monitoring the conditions of rotating machineries. Most of the conventional methods for fault diagnosis using acoustic and vibration

  8. Stochastic Nature of Precisely Timed Spike Patterns in Visual System Neuronal Responses

    E-print Network

    Oram, Mike

    ,1 M. C. WIENER,1 R. LESTIENNE,2 AND B. J. RICHMOND1 1 National Institute of Mental Health, National., M. C. Wiener, R. Lestienne, and B. J. Richmond. Stochastic nature of precisely timed spike patterns in visual system neuronal responses. J. Neurophysiol. 81: 3021­3033, 1999. It is not clear how information

  9. FlyExpress: Visual mining of spatiotemporal patterns for genes and publications in Drosophila embryogenesis

    E-print Network

    Ye, Jieping

    melanogaster is a canonical model organism for understanding animal development. More than one hundred thousand Drosophila melanogaster embryogenesis. By clicking on specific locations in pictures of fly embryos from1 FlyExpress: Visual mining of spatiotemporal patterns for genes and publications in Drosophila

  10. Nurses' Behaviors and Visual Scanning Patterns May Reduce Patient Identification Errors

    ERIC Educational Resources Information Center

    Marquard, Jenna L.; Henneman, Philip L.; He, Ze; Jo, Junghee; Fisher, Donald L.; Henneman, Elizabeth A.

    2011-01-01

    Patient identification (ID) errors occurring during the medication administration process can be fatal. The aim of this study is to determine whether differences in nurses' behaviors and visual scanning patterns during the medication administration process influence their capacities to identify patient ID errors. Nurse participants (n = 20)…

  11. STATIONARY PATTERN ADAPTATION AND THE EARLY COMPONENTS IN HUMAN VISUAL EVOKED POTENTIALS

    EPA Science Inventory

    Pattern-onset visual evoked potentials were elicited from humans by sinusoidal gratings of 0.5., 1, 2 and 4 cpd (cycles/degree) following adaptation to a blank field or one of the gratings. The wave forms recorded after blank field adaptation showed an early positive component, P...

  12. Flexibility and Coordination among Acts of Visualization and Analysis in a Pattern Generalization Activity

    ERIC Educational Resources Information Center

    Nilsson, Per; Juter, Kristina

    2011-01-01

    This study aims at exploring processes of flexibility and coordination among acts of visualization and analysis in students' attempt to reach a general formula for a three-dimensional pattern generalizing task. The investigation draws on a case-study analysis of two 15-year-old girls working together on a task in which they are asked to calculate…

  13. Visualization of Flow Patterns in the Bonneville 2nd Powerhouse Forebay

    SciTech Connect

    Serkowski, John A.; Rakowski, Cynthia L.; Ebner, Laurie L.

    2002-12-31

    Three-dimensional (3D) computational fluid dynamics (CFD) models are increasingly being used to study forebay and tailrace flow systems associated with hydroelectric projects. This paper describes the fundamentals of creating effective 3D data visualizations from CFD model results using a case study from the Bonneville Dam. These visualizations enhance the utility of CFD models by helping the researcher and end user better understand the model results. To develop visualizations for the Bonneville Dam forebay model, we used specialized, but commonly available software and a standard high-end microprocessor workstation. With these tools we were able to compare flow patterns among several operational scenarios by producing a variety of contour, vector, stream-trace, and vortex-core plots. The differences in flow patterns we observed could impact efforts to divert downstream-migrating fish around powerhouse turbines.

  14. Patterns of visual attention to faces and objects in autism spectrum disorder

    PubMed Central

    McPartland, James C.; Webb, Sara Jane; Keehn, Brandon; Dawson, Geraldine

    2011-01-01

    This study used eye-tracking to examine visual attention to faces and objects in adolescents with autism spectrum disorder (ASD) and typical peers. Point of gaze was recorded during passive viewing of images of human faces, inverted human faces, monkey faces, three-dimensional curvilinear objects, and two-dimensional geometric patterns. Individuals with ASD obtained lower scores on measures of face recognition and social-emotional functioning but exhibited similar patterns of visual attention. In individuals with ASD, face recognition performance was associated with social adaptive function. Results highlight heterogeneity in manifestation of social deficits in ASD and suggest that naturalistic assessments are important for quantifying atypicalities in visual attention. PMID:20499148

  15. On Assisting a Visual-Facial Affect Recognition System with Keyboard-Stroke Pattern Information

    NASA Astrophysics Data System (ADS)

    Stathopoulou, I.-O.; Alepis, E.; Tsihrintzis, G. A.; Virvou, M.

    Towards realizing a multimodal affect recognition system, we are considering the advantages of assisting a visual-facial expression recognition system with keyboard-stroke pattern information. Our work is based on the assumption that the visual-facial and keyboard modalities are complementary to each other and that their combination can significantly improve the accuracy in affective user models. Specifically, we present and discuss the development and evaluation process of two corresponding affect recognition subsystems, with emphasis on the recognition of 6 basic emotional states, namely happiness, sadness, surprise, anger and disgust as well as the emotion-less state which we refer to as neutral. We find that emotion recognition by the visual-facial modality can be aided greatly by keyboard-stroke pattern information and the combination of the two modalities can lead to better results towards building a multimodal affect recognition system.

  16. Visual motion modulates pattern sensitivity ahead, behind, and beside motion

    PubMed Central

    Arnold, Derek H.; Marinovic, Welber; Whitney, David

    2014-01-01

    Retinal motion can modulate visual sensitivity. For instance, low contrast drifting waveforms (targets) can be easier to detect when abutting the leading edges of movement in adjacent high contrast waveforms (inducers), rather than the trailing edges. This target-inducer interaction is contingent on the adjacent waveforms being consistent with one another – in-phase as opposed to out-of-phase. It has been suggested that this happens because there is a perceptually explicit predictive signal at leading edges of motion that summates with low contrast physical input – a ‘predictive summation’. Another possible explanation is a phase sensitive ‘spatial summation’, a summation of physical inputs spread across the retina (not predictive signals). This should be non-selective in terms of position – it should be evident at leading, adjacent, and at trailing edges of motion. To tease these possibilities apart, we examined target sensitivity at leading, adjacent, and trailing edges of motion. We also examined target sensitivity adjacent to flicker, and for a stimulus that is less susceptible to spatial summation, as it sums to grey across a small retinal expanse. We found evidence for spatial summation in all but the last condition. Finally, we examined sensitivity to an absence of signal at leading and trailing edges of motion, finding greater sensitivity at leading edges. These results are inconsistent with the existence of a perceptually explicit predictive signal in advance of drifting waveforms. Instead, we suggest that phase-contingent target-inducer modulations of sensitivity are explicable in terms of a directionally modulated spatial summation. PMID:24699250

  17. “A Textbook Case Revisited”: Visual Rhetoric and Series Patterning in the American Museum of Natural History's Horse Evolution Displays

    Microsoft Academic Search

    Jeremiah Dyehouse

    2011-01-01

    This article describes the development of visual rhetoric in a historically significant museum exhibit. The study documents rhetorical change in the museum's displays, specifically in visual series depicting the horse's evolutionary development. The study also exposes the purpose of series patterning in the renovated display and the multiple views on scientific visualization this display implies. Such an analysis suggests the

  18. Effects of contour enhancement on low-vision preference and visual search

    PubMed Central

    Satgunam, PremNandhini; Woods, Russell L; Luo, Gang; Bronstad, P Matthew; Reynolds, Zachary; Ramachandra, Chaithanya; Mel, Bartlett W.; Peli, Eli

    2012-01-01

    PURPOSE To determine whether image enhancement improves visual search performance and whether enhanced images were also preferred by subjects with vision impairment. METHOD Subjects (n=24) with vision impairment (vision: 20/52 to 20/240) completed visual search and preference tasks for 150 static images that were enhanced to increase object contours’ visual saliency. Subjects were divided into two groups and were shown three enhancement levels. Original and Medium enhancement were shown to both groups. High enhancement was shown to Group 1 and Low was shown to Group 2. For search, subjects pointed to an object that matched a search target displayed at the top left of the screen. An “integrated search performance” measure (area under the curve of cumulative correct response rate over search time) quantified performance. For preference, subjects indicated the preferred side when viewing the same image with different enhancement levels on side-by-side HDTVs. RESULTS Contour enhancement did not improve performance in the visual search task. Group 1 subjects significantly (p<0.001) rejected the High enhancement, and showed no preference for Medium enhancement over the Original images. Group 2 subjects significantly preferred (p<0.001) both the Medium and the Low enhancement levels over Original. Contrast sensitivity was correlated with both preference and performance; subjects with worse contrast sensitivity performed worse in the search task (?=0.77, p<0.001) and preferred more enhancement (?=?0.47, p=0.02). No correlation between visual search performance and enhancement preference was found. However, a small group of subjects (n=6) in a narrow range of mid-contrast sensitivity performed better with the enhancement and most (n=5) also preferred the enhancement. CONCLUSIONS Preferences for image enhancement can be dissociated from search performance in people with vision impairment. Further investigations are needed to study the relationships between preference and performance for a narrow range of mid-contrast sensitivity where a beneficial effect of enhancement may exist. PMID:22863793

  19. Activation of New Attentional Templates for Real-world Objects in Visual Search.

    PubMed

    Nako, Rebecca; Smith, Tim J; Eimer, Martin

    2015-05-01

    Visual search is controlled by representations of target objects (attentional templates). Such templates are often activated in response to verbal descriptions of search targets, but it is unclear whether search can be guided effectively by such verbal cues. We measured ERPs to track the activation of attentional templates for new target objects defined by word cues. On each trial run, a word cue was followed by three search displays that contained the cued target object among three distractors. Targets were detected more slowly in the first display of each trial run, and the N2pc component (an ERP marker of attentional target selection) was attenuated and delayed for the first relative to the two successive presentations of a particular target object, demonstrating limitations in the ability of word cues to activate effective attentional templates. N2pc components to target objects in the first display were strongly affected by differences in object imageability (i.e., the ability of word cues to activate a target-matching visual representation). These differences were no longer present for the second presentation of the same target objects, indicating that a single perceptual encounter is sufficient to activate a precise attentional template. Our results demonstrate the superiority of visual over verbal target specifications in the control of visual search, highlight the fact that verbal descriptions are more effective for some objects than others, and suggest that the attentional templates that guide search for particular real-world target objects are analog visual representations. PMID:25321485

  20. Eye fixation determined by the visual shape and semantic matches in language-mediated visual search 

    E-print Network

    Shi, Lei

    2007-08-24

    When participants are presented simultaneously a visual display with spoken input, eye fixation could be determined by a match between representations from spoken input and visual objects. Previous studies found that eye fixation on the semantic...

  1. Pattern Rate and Interpattern Interval in Development of Matching Simple Auditory-Visual Patterns

    ERIC Educational Resources Information Center

    Alexander, Richard

    1977-01-01

    Experiment 1 compared 6- and 8-year-old boys in inter- and intramodal matching of fast or slow spatiotemporal patterns with long or short interpattern intervals. Experiment 2 made the same comparisons for 7- and 9-year-old boys using temporal patterns. (Author/JMB)

  2. Repetition Suppression and Multi-Voxel Pattern Similarity Differentially Track Implicit and Explicit Visual Memory

    PubMed Central

    Chun, Marvin M.; Kuhl, Brice A.

    2013-01-01

    Repeated exposure to a visual stimulus is associated with corresponding reductions in neural activity, particularly within visual cortical areas. It has been argued that this phenomenon of repetition suppression is related to increases in processing fluency or implicit memory. However, repetition of a visual stimulus can also be considered in terms of the similarity of the pattern of neural activity elicited at each exposure—a measure that has recently been linked to explicit memory. Despite the popularity of each of these measures, direct comparisons between the two have been limited, and the extent to which they differentially (or similarly) relate to behavioral measures of memory has not been clearly established. In the present study, we compared repetition suppression and pattern similarity as predictors of both implicit and explicit memory. Using functional magnetic resonance imaging, we scanned 20 participants while they viewed and categorized repeated presentations of scenes. Repetition priming (facilitated categorization across repetitions) was used as a measure of implicit memory, and subsequent scene recognition was used as a measure of explicit memory. We found that repetition priming was predicted by repetition suppression in prefrontal, parietal, and occipitotemporal regions; however, repetition priming was not predicted by pattern similarity. In contrast, subsequent explicit memory was predicted by pattern similarity (across repetitions) in some of the same occipitotemporal regions that exhibited a relationship between priming and repetition suppression; however, explicit memory was not related to repetition suppression. This striking double dissociation indicates that repetition suppression and pattern similarity differentially track implicit and explicit learning. PMID:24027275

  3. An instructive role for patterned spontaneous retinal activity in mouse visual map development

    PubMed Central

    Xu, Hong-ping; Furman, Moran; Mineur, Yann S.; Chen, Hui; King, Sarah L.; Zenisek, David; Zhou, Z. Jimmy; Butts, Daniel A.; Tian, Ning; Picciotto, Marina R.; Crair, Michael C.

    2011-01-01

    SUMMARY Complex neural circuits in the mammalian brain develop through a combination of genetic instruction and activity-dependent refinement. The relative role of these factors and the form of neuronal activity responsible for circuit development is a matter of significant debate. In the mammalian visual system, retinal ganglion cell projections to the brain are mapped with respect to retinotopic location and eye of origin. We manipulated the pattern of spontaneous retinal waves present during development without changing overall activity levels through the transgenic expression of ?2-nicotinic acetylcholine receptors in retinal ganglion cells of mice. We used this manipulation to demonstrate that spontaneous retinal activity is not just permissive, but instructive in the emergence of eye-specific segregation and retinotopic refinement in the mouse visual system. This suggests that specific patterns of spontaneous activity throughout the developing brain are essential in the emergence of specific and distinct patterns of neuronal connectivity. PMID:21689598

  4. Disturbance of visual search by stimulating to posterior parietal cortex in the brain using transcranial magnetic stimulation

    NASA Astrophysics Data System (ADS)

    Iramina, Keiji; Ge, Sheng; Hyodo, Akira; Hayami, Takehito; Ueno, Shoogo

    2009-04-01

    In this study, we applied a transcranial magnetic stimulation (TMS) to investigate the temporal aspect for the functional processing of visual attention. Although it has been known that right posterior parietal cortex (PPC) in the brain has a role in certain visual search tasks, there is little knowledge about the temporal aspect of this area. Three visual search tasks that have different difficulties of task execution individually were carried out. These three visual search tasks are the "easy feature task," the "hard feature task," and the "conjunction task." To investigate the temporal aspect of the PPC involved in the visual search, we applied various stimulus onset asynchronies (SOAs) and measured the reaction time of the visual search. The magnetic stimulation was applied on the right PPC or the left PPC by the figure-eight coil. The results show that the reaction times of the hard feature task are longer than those of the easy feature task. When SOA=150 ms, compared with no-TMS condition, there was a significant increase in target-present reaction time when TMS pulses were applied. We considered that the right PPC was involved in the visual search at about SOA=150 ms after visual stimulus presentation. The magnetic stimulation to the right PPC disturbed the processing of the visual search. However, the magnetic stimulation to the left PPC gives no effect on the processing of the visual search.

  5. Effects of Spatial Configuration on Search of Visual Displays. Umea Psychological Reports No. 151.

    ERIC Educational Resources Information Center

    Brannstrom, Lauritz

    The visual scanning of redundant and random spatial configurations of two-digit numbers was investigated in a target recognition task. The experimental technique involved a brief exposure of a probe (a two-digit number) at the center of the visual field, followed by a spatial pattern of 16 two-digit numbers which included the matching target in…

  6. A ground-like surface facilitates visual search in chimpanzees (Pan troglodytes).

    PubMed

    Imura, Tomoko; Tomonaga, Masaki

    2013-01-01

    Ground surfaces play an important role in terrestrial species' locomotion and ability to manipulate objects. In humans, ground surfaces have been found to offer significant advantages in distance perception and visual-search tasks ("ground dominance"). The present study used a comparative perspective to investigate the ground-dominance effect in chimpanzees, a species that spends time both on the ground and in trees. During the experiments chimpanzees and humans engaged in a search for a cube on a computer screen; the target cube was darker than other cubes. The search items were arranged on a ground-like or ceiling-like surface, which was defined by texture gradients and shading. The findings indicate that a ground-like, but not a ceiling-like, surface facilitated the search for a difference in luminance among both chimpanzees and humans. Our findings suggest the operation of a ground-dominance effect on visual search in both species. PMID:23917381

  7. Human cortical mechanisms of visual attention during orienting and search.

    PubMed Central

    Corbetta, M; Shulman, G L

    1998-01-01

    Functional anatomical studies indicate that a set of neural signals in parietal and frontal cortex mediates the covert allocation of attention to visual locations across a wide variety of visual tasks. This frontoparietal network includes areas, such as the frontal eye field and supplementary eye field. This anatomical overlap suggests that shifts of attention to visual locations of objects recruit areas involved in oculomotor programming and execution. Finally, the fronto-parietal network may be the source of spatial attentional modulations in the ventral visual system during object recognition or discrimination. PMID:9770228

  8. Acute exercise and aerobic fitness influence selective attention during visual search

    PubMed Central

    Bullock, Tom; Giesbrecht, Barry

    2014-01-01

    Successful goal directed behavior relies on a human attention system that is flexible and able to adapt to different conditions of physiological stress. However, the effects of physical activity on multiple aspects of selective attention and whether these effects are mediated by aerobic capacity, remains unclear. The aim of the present study was to investigate the effects of a prolonged bout of physical activity on visual search performance and perceptual distraction. Two groups of participants completed a hybrid visual search flanker/response competition task in an initial baseline session and then at 17-min intervals over a 2 h 16 min test period. Participants assigned to the exercise group engaged in steady-state aerobic exercise between completing blocks of the visual task, whereas participants assigned to the control group rested in between blocks. The key result was a correlation between individual differences in aerobic capacity and visual search performance, such that those individuals that were more fit performed the search task more quickly. Critically, this relationship only emerged in the exercise group after the physical activity had begun. The relationship was not present in either group at baseline and never emerged in the control group during the test period, suggesting that under these task demands, aerobic capacity may be an important determinant of visual search performance under physical stress. The results enhance current understanding about the relationship between exercise and cognition, and also inform current models of selective attention. PMID:25426094

  9. Playing shooter and driving videogames improves top-down guidance in visual search.

    PubMed

    Wu, Sijing; Spence, Ian

    2013-05-01

    Playing action videogames is known to improve visual spatial attention and related skills. Here, we showed that playing action videogames also improves classic visual search, as well as the ability to locate targets in a dual search that mimics certain aspects of an action videogame. In Experiment 1A, first-person shooter (FPS) videogame players were faster than nonplayers in both feature search and conjunction search, and in Experiment 1B, they were faster and more accurate in a peripheral search and identification task while simultaneously performing a central search. In Experiment 2, we showed that 10 h of play could improve the performance of nonplayers on each of these tasks. Three different genres of videogames were used for training: two action games and a 3-D puzzle game. Participants who played an action game (either an FPS or a driving game) achieved greater gains on all search tasks than did those who trained using the puzzle game. Feature searches were faster after playing an action videogame, suggesting that players developed a better target template to guide search in a top-down manner. The results of the dual search suggest that, in addition to enhancing the ability to divide attention, playing an action game improves the top-down guidance of attention to possible target locations. The results have practical implications for the development of training tools to improve perceptual and cognitive skills. PMID:23460295

  10. JOB SEARCH PATTERNS OF COLLEGE GRADUATES: THE ROLE OF SOCIAL CAPITAL

    E-print Network

    Coonfield, Emily Suzanne

    2012-12-31

    This dissertation addresses job search patterns of college graduates and the implications of social capital by race and class. The purpose of this study is to explore (1) how the job search transpires for recent college graduates, (2) how potential...

  11. Binocular saccade coordination in reading and visual search: a developmental study in typical reader and dyslexic children

    PubMed Central

    Seassau, Magali; Gérard, Christophe Loic; Bui-Quoc, Emmanuel; Bucci, Maria Pia

    2014-01-01

    Studies dealing with developmental aspects of binocular eye movement behavior during reading are scarce. In this study we have explored binocular strategies during reading and visual search tasks in a large population of dyslexic and typical readers. Binocular eye movements were recorded using a video-oculography system in 43 dyslexic children (aged 8–13) and in a group of 42 age-matched typical readers. The main findings are: (i) ocular motor characteristics of dyslexic children are impaired in comparison to those reported in typical children in reading task; (ii) a developmental effect exists in reading in control children, in dyslexic children the effect of development was observed only on fixation durations; and (iii) ocular motor behavior in the visual search tasks is similar for dyslexic children and for typical readers, except for the disconjugacy during and after the saccade: dyslexic children are impaired in comparison to typical children. Data reported here confirms and expands previous studies on children’s reading. Both reading skills and binocular saccades coordination improve with age in typical readers. The atypical eye movement’s patterns observed in dyslexic children suggest a deficiency in the visual attentional processing as well as an impairment of the ocular motor saccade and vergence systems interaction. PMID:25400559

  12. Does crossmodal correspondence modulate the facilitatory effect of auditory cues on visual search?

    PubMed

    Klapetek, Anna; Ngo, Mary Kim; Spence, Charles

    2012-08-01

    The "pip-and-pop effect" refers to the facilitation of search for a visual target (a horizontal or vertical bar whose color changes frequently) among multiple visual distractors (tilted bars also changing color unpredictably) by the presentation of a spatially uninformative auditory cue synchronized with the color change of the visual target. In the present study, the visual stimuli in the search display changed brightness instead of color, and the crossmodal congruency between the pitch of the auditory cue and the brightness of the visual target was manipulated. When cue presence and cue congruency were randomly varied between trials (Experiment 1), both congruent cues (low-frequency tones synchronized with dark target states or high-frequency tones synchronized with bright target states) and incongruent cues (the reversed mapping) facilitated visual search performance equally, relative to a no-cue baseline condition. However, when cue congruency was blocked and the participants were informed about the pitch-brightness mapping in the cue-present blocks (Experiment 2), performance was significantly enhanced when the cue and target were crossmodally congruent as compared to when they were incongruent. These results therefore suggest that the crossmodal congruency between auditory pitch and visual brightness can influence performance in the pip-and-pop task by means of top-down facilitation. PMID:22648604

  13. Visual pattern discrimination by population retinal ganglion cells' activities during natural movie stimulation.

    PubMed

    Zhang, Ying-Ying; Wang, Ru-Bin; Pan, Xiao-Chuan; Gong, Hai-Qing; Liang, Pei-Ji

    2014-02-01

    In the visual system, neurons often fire in synchrony, and it is believed that synchronous activities of group neurons are more efficient than single cell response in transmitting neural signals to down-stream neurons. However, whether dynamic natural stimuli are encoded by dynamic spatiotemporal firing patterns of synchronous group neurons still needs to be investigated. In this paper we recorded the activities of population ganglion cells in bullfrog retina in response to time-varying natural images (natural scene movie) using multi-electrode arrays. In response to some different brief section pairs of the movie, synchronous groups of retinal ganglion cells (RGCs) fired with similar but different spike events. We attempted to discriminate the movie sections based on temporal firing patterns of single cells and spatiotemporal firing patterns of the synchronous groups of RGCs characterized by a measurement of subsequence distribution discrepancy. The discrimination performance was assessed by a classification method based on Support Vector Machines. Our results show that different movie sections of the natural movie elicited reliable dynamic spatiotemporal activity patterns of the synchronous RGCs, which are more efficient in discriminating different movie sections than the temporal patterns of the single cells' spike events. These results suggest that, during natural vision, the down-stream neurons may decode the visual information from the dynamic spatiotemporal patterns of the synchronous group of RGCs' activities. PMID:24465283

  14. Mining patterns in persistent surveillance systems with smart query and visual analytics

    NASA Astrophysics Data System (ADS)

    Habibi, Mohammad S.; Shirkhodaie, Amir

    2013-05-01

    In Persistent Surveillance Systems (PSS) the ability to detect and characterize events geospatially help take pre-emptive steps to counter adversary's actions. Interactive Visual Analytic (VA) model offers this platform for pattern investigation and reasoning to comprehend and/or predict such occurrences. The need for identifying and offsetting these threats requires collecting information from diverse sources, which brings with it increasingly abstract data. These abstract semantic data have a degree of inherent uncertainty and imprecision, and require a method for their filtration before being processed further. In this paper, we have introduced an approach based on Vector Space Modeling (VSM) technique for classification of spatiotemporal sequential patterns of group activities. The feature vectors consist of an array of attributes extracted from generated sensors semantic annotated messages. To facilitate proper similarity matching and detection of time-varying spatiotemporal patterns, a Temporal-Dynamic Time Warping (DTW) method with Gaussian Mixture Model (GMM) for Expectation Maximization (EM) is introduced. DTW is intended for detection of event patterns from neighborhood-proximity semantic frames derived from established ontology. GMM with EM, on the other hand, is employed as a Bayesian probabilistic model to estimated probability of events associated with a detected spatiotemporal pattern. In this paper, we present a new visual analytic tool for testing and evaluation group activities detected under this control scheme. Experimental results demonstrate the effectiveness of proposed approach for discovery and matching of subsequences within sequentially generated patterns space of our experiments.

  15. How fast can you change your mind? The speed of top-down guidance in visual search

    E-print Network

    conjunction search. Word cues were slower and never as effective. Experiment 3 replicated this resultHow fast can you change your mind? The speed of top-down guidance in visual search Jeremy M. Wolfe search tasks involve many searches for the same target, while in the real world we typically change our

  16. Case study of visualizing global user download patterns using Google Earth and NASA World Wind

    NASA Astrophysics Data System (ADS)

    Zong, Ziliang; Job, Joshua; Zhang, Xuesong; Nijim, Mais; Qin, Xiao

    2012-01-01

    Geo-visualization is significantly changing the way we view spatial data and discover information. On the one hand, a large number of spatial data are generated every day. On the other hand, these data are not well utilized due to the lack of free and easily used data-visualization tools. This becomes even worse when most of the spatial data remains in the form of plain text such as log files. This paper describes a way of visualizing massive plain-text spatial data at no cost by utilizing Google Earth and NASA World Wind. We illustrate our methods by visualizing over 170,000 global download requests for satellite images maintained by the Earth Resources Observation and Science (EROS) Center of U.S. Geological Survey (USGS). Our visualization results identify the most popular satellite images around the world and discover the global user download patterns. The benefits of this research are: 1. assisting in improving the satellite image downloading services provided by USGS, and 2. providing a proxy for analyzing the "hot spot" areas of research. Most importantly, our methods demonstrate an easy way to geo-visualize massive textual spatial data, which is highly applicable to mining spatially referenced data and information on a wide variety of research domains (e.g., hydrology, agriculture, atmospheric science, natural hazard, and global climate change).

  17. Long-Term Memory Search across the Visual Brain

    PubMed Central

    Fedurco, Milan

    2012-01-01

    Signal transmission from the human retina to visual cortex and connectivity of visual brain areas are relatively well understood. How specific visual perceptions transform into corresponding long-term memories remains unknown. Here, I will review recent Blood Oxygenation Level-Dependent functional Magnetic Resonance Imaging (BOLD fMRI) in humans together with molecular biology studies (animal models) aiming to understand how the retinal image gets transformed into so-called visual (retinotropic) maps. The broken object paradigm has been chosen in order to illustrate the complexity of multisensory perception of simple objects subject to visual —rather than semantic— type of memory encoding. The author explores how amygdala projections to the visual cortex affect the memory formation and proposes the choice of experimental techniques needed to explain our massive visual memory capacity. Maintenance of the visual long-term memories is suggested to require recycling of GluR2-containing ?-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR) and ?2-adrenoreceptors at the postsynaptic membrane, which critically depends on the catalytic activity of the N-ethylmaleimide-sensitive factor (NSF) and protein kinase PKM?. PMID:22900206

  18. Geometrical illusions and the response of neurones in the cat's visual cortex to angle patterns

    PubMed Central

    Burns, B. Delisle; Pritchard, Roy

    1971-01-01

    1. This report describes the responses of thirty-six single neurones in the primary visual area of the cat's neurologically isolated and unanaesthetized forebrain, to movements of thin white lines across the visual field. The experiments were designed to record the effects upon the response to a single test line of an added line, which was either parallel to the test line or joined it, making an angle-pattern of 30°. Unit responses were measured in terms of the peak probability of firing derived from a post-stimulus histogram. 2. All of the cortical neurones tested exhibited a preferred orientation for stimulation by the test line, i.e. an orientation of the line which produced a maximal response when the line passed through the centre of the unit's receptive field. 3. There was no evidence that the orientation of a single test line preferred by cortical neurones was different from that preferred by the same cell when excited by an angle pattern, one arm of which was the original test line. 4. The position of a test line (with preferred orientation) in the visual field that produced a maximal response from cortical neurones, was not always the same as the position for maximal response, when a second line was added to make either an angle pattern or to make a pattern of two parallel lines. 5. Where the two lines of these patterns were close together and separated by less than the radius of the receptive field, the position for maximal response to the test line was shifted towards the added line. Where the two lines were further apart than this but separated by less than a receptive field diameter, the optimal position for the test line was displaced away from the added line. 6. Some evidence was found of a lateral inhibition in the visual system, sufficient to account for the displacements described in paragraphs 4 and 5 above. 7. It is concluded that the tip of an angle pattern of 30° produces a distorted cortical image within the primary visual area. 8. This neural distortion of sensory information seems adequate to explain the well known illusions of orientation that are associated with human perception of patterns containing acute angles. PMID:5102531

  19. White Matter Tract Integrity Predicts Visual Search Performance in Young and Older Adults

    PubMed Central

    Bennett, Ilana J.; Motes, Michael A.; Rao, Neena K.; Rypma, Bart

    2011-01-01

    Functional imaging research has identified fronto-parietal attention networks involved in visual search, with mixed evidence regarding whether different networks are engaged when the search target differs from distracters by a single (elementary) versus multiple (conjunction) features. Neural correlates of visual search, and their potential dissociation, were examined here using integrity of white matter connecting the fronto-parietal networks. The effect of aging on these brain-behavior relationships was also of interest. Younger and older adults performed a visual search task and underwent diffusion tensor imaging (DTI) to reconstruct two fronto-parietal (superior and inferior longitudinal fasciculus, SLF and ILF) and two midline (genu, splenium) white matter tracts. As expected, results revealed age-related declines in conjunction, but not elementary, search performance; and in ILF and genu tract integrity. Importantly, integrity of the SLF, ILF, and genu tracts predicted search performance (conjunction and elementary), with no significant age group differences in these relationships. Thus, integrity of white matter tracts connecting fronto-parietal attention networks contributes to search performance in younger and older adults. PMID:21402431

  20. Visual Search Performance in the Autism Spectrum II: The Radial Frequency Search Task with Additional Segmentation Cues

    ERIC Educational Resources Information Center

    Almeida, Renita A.; Dickinson, J. Edwin; Maybery, Murray T.; Badcock, Johanna C.; Badcock, David R.

    2010-01-01

    The Embedded Figures Test (EFT) requires detecting a shape within a complex background and individuals with autism or high Autism-spectrum Quotient (AQ) scores are faster and more accurate on this task than controls. This research aimed to uncover the visual processes producing this difference. Previously we developed a search task using radial…

  1. Analysis of microsaccades and pupil dilation reveals a common decisional origin during visual search.

    PubMed

    Privitera, Claudio M; Carney, Thom; Klein, Stanley; Aguilar, Mario

    2014-02-01

    During free viewing visual search, observers often refixate the same locations several times before and after target detection is reported with a button press. We analyzed the rate of microsaccades in the sequence of refixations made during visual search and found two important components. One related to the visual content of the region being fixated; fixations on targets generate more microsaccades and more microsaccades are generated for those targets that are more difficult to disambiguate. The other empathizes non-visual decisional processes; fixations containing the button press generate more microsaccades than those made on the same target but without the button press. Pupil dilation during the same refixations reveals a similar modulation. We inferred that generic sympathetic arousal mechanisms are part of the articulated complex of perceptual processes governing fixational eye movements. PMID:24333280

  2. Comparison of visualized turbine endwall secondary flows and measured heat transfer patterns

    NASA Technical Reports Server (NTRS)

    Gaugler, R. E.; Russell, L. M.

    1984-01-01

    Various flow visualization techniques were used to define the seondary flows near the endwall in a large heat transfer data. A comparison of the visualized flow patterns and the measured Stanton number distribution was made for cases where the inlet Reynolds number and exit Mach number were matched. Flows were visualized by using neutrally buoyant helium-filled soap bubbles, by using smoke from oil soaked cigars, and by a few techniques using permanent marker pen ink dots and synthetic wintergreen oil. Details of the horseshoe vortex and secondary flows can be directly compared with heat transfer distribution. Near the cascade entrance there is an obvious correlation between the two sets of data, but well into the passage the effect of secondary flow is not as obvious. Previously announced in STAR as N83-14435

  3. Comparison of visualized turbine endwall secondary flows and measured heat transfer patterns

    NASA Technical Reports Server (NTRS)

    Gaugler, R. E.; Russell, L. M.

    1983-01-01

    Various flow visualization techniques were used to define the secondary flows near the endwall in a large heat transfer data. A comparison of the visualized flow patterns and the measured Stanton number distribution was made for cases where the inlet Reynolds number and exit Mach number were matched. Flows were visualized by using neutrally buoyant helium-filled soap bubbles, by using smoke from oil soaked cigars, and by a few techniques using permanent marker pen ink dots and synthetic wintergreen oil. Details of the horseshoe vortex and secondary flows can be directly compared with heat transfer distribution. Near the cascade entrance there is an obvious correlation between the two sets of data, but well into the passage the effect of secondary flow is not as obvious.

  4. Visualizing magnetocrystalline anisotropy field distribution of patterned triangular L10 FePt nanodots

    NASA Astrophysics Data System (ADS)

    Zhong, Hai; Zhang, Kaiming; Wei, Dan; Wang, Sumei; Yuan, Jun

    2015-02-01

    Measuring magnetocrystalline anisotropy field distribution of patterned magnetic nanodots using a microscopically visualizing way is important for understanding some important magnetic behaviors such as switching field distribution (SFD) of patterned recording media. We present a detailed analysis of the remanent domain structures of L10-FePt triangular nanodots as revealed by high resolution magnetic force microscopy (MFM) with the help of micromagnetic simulation, showing that the domain structure diversity can effectively account for a dot-to-dot variation of the magnetocrystalline anisotropy field. Our method could shed light not only on understanding the fundamental causes of a wider SFD but also on designing future nanostructured magnetic devices.

  5. Giant honeybees (Apis dorsata) mob wasps away from the nest by directed visual patterns.

    PubMed

    Kastberger, Gerald; Weihmann, Frank; Zierler, Martina; Hötzl, Thomas

    2014-11-01

    The open nesting behaviour of giant honeybees (Apis dorsata) accounts for the evolution of a series of defence strategies to protect the colonies from predation. In particular, the concerted action of shimmering behaviour is known to effectively confuse and repel predators. In shimmering, bees on the nest surface flip their abdomens in a highly coordinated manner to generate Mexican wave-like patterns. The paper documents a further-going capacity of this kind of collective defence: the visual patterns of shimmering waves align regarding their directional characteristics with the projected flight manoeuvres of the wasps when preying in front of the bees' nest. The honeybees take here advantage of a threefold asymmetry intrinsic to the prey-predator interaction: (a) the visual patterns of shimmering turn faster than the wasps on their flight path, (b) they "follow" the wasps more persistently (up to 100 ms) than the wasps "follow" the shimmering patterns (up to 40 ms) and (c) the shimmering patterns align with the wasps' flight in all directions at the same strength, whereas the wasps have some preference for horizontal correspondence. The findings give evidence that shimmering honeybees utilize directional alignment to enforce their repelling power against preying wasps. This phenomenon can be identified as predator driving which is generally associated with mobbing behaviour (particularly known in selfish herds of vertebrate species), which is, until now, not reported in insects. PMID:25169944

  6. Giant honeybees ( Apis dorsata) mob wasps away from the nest by directed visual patterns

    NASA Astrophysics Data System (ADS)

    Kastberger, Gerald; Weihmann, Frank; Zierler, Martina; Hötzl, Thomas

    2014-11-01

    The open nesting behaviour of giant honeybees ( Apis dorsata) accounts for the evolution of a series of defence strategies to protect the colonies from predation. In particular, the concerted action of shimmering behaviour is known to effectively confuse and repel predators. In shimmering, bees on the nest surface flip their abdomens in a highly coordinated manner to generate Mexican wave-like patterns. The paper documents a further-going capacity of this kind of collective defence: the visual patterns of shimmering waves align regarding their directional characteristics with the projected flight manoeuvres of the wasps when preying in front of the bees' nest. The honeybees take here advantage of a threefold asymmetry intrinsic to the prey-predator interaction: (a) the visual patterns of shimmering turn faster than the wasps on their flight path, (b) they "follow" the wasps more persistently (up to 100 ms) than the wasps "follow" the shimmering patterns (up to 40 ms) and (c) the shimmering patterns align with the wasps' flight in all directions at the same strength, whereas the wasps have some preference for horizontal correspondence. The findings give evidence that shimmering honeybees utilize directional alignment to enforce their repelling power against preying wasps. This phenomenon can be identified as predator driving which is generally associated with mobbing behaviour (particularly known in selfish herds of vertebrate species), which is, until now, not reported in insects.

  7. Giant honeybees (Apis dorsata) mob wasps away from the nest by directed visual patterns

    NASA Astrophysics Data System (ADS)

    Kastberger, Gerald; Weihmann, Frank; Zierler, Martina; Hötzl, Thomas

    2014-08-01

    The open nesting behaviour of giant honeybees (Apis dorsata) accounts for the evolution of a series of defence strategies to protect the colonies from predation. In particular, the concerted action of shimmering behaviour is known to effectively confuse and repel predators. In shimmering, bees on the nest surface flip their abdomens in a highly coordinated manner to generate Mexican wave-like patterns. The paper documents a further-going capacity of this kind of collective defence: the visual patterns of shimmering waves align regarding their directional characteristics with the projected flight manoeuvres of the wasps when preying in front of the bees' nest. The honeybees take here advantage of a threefold asymmetry intrinsic to the prey-predator interaction: (a) the visual patterns of shimmering turn faster than the wasps on their flight path, (b) they "follow" the wasps more persistently (up to 100 ms) than the wasps "follow" the shimmering patterns (up to 40 ms) and (c) the shimmering patterns align with the wasps' flight in all directions at the same strength, whereas the wasps have some preference for horizontal correspondence. The findings give evidence that shimmering honeybees utilize directional alignment to enforce their repelling power against preying wasps. This phenomenon can be identified as predator driving which is generally associated with mobbing behaviour (particularly known in selfish herds of vertebrate species), which is, until now, not reported in insects.

  8. 3D pattern of brain abnormalities in Williams syndrome visualized using tensor-based morphometry

    Microsoft Academic Search

    Ming-Chang Chiang; Allan L. Reiss; Agatha D. Lee; Ursula Bellugi; Albert M. Galaburda; Julie R. Korenberg; Debra L. Mills; Arthur W. Toga; Paul M. Thompson

    2007-01-01

    Williams syndrome (WS) is a neurodevelopmental disorder associated with deletion of ?20 contiguous genes in chromosome band 7q11.23. Individuals with WS exhibit mild to moderate mental retardation, but are relatively more proficient in specific language and musical abilities. We used tensor-based morphometry (TBM) to visualize the complex pattern of gray\\/white matter reductions in WS, based on fluid registration of structural

  9. Facilitation of visual pattern recognition by extraction of relevant features from microscopic traffic data

    E-print Network

    Fields, Matthew James

    2009-05-15

    FACILITATION OF VISUAL PATTERN RECOGNITION BY EXTRACTION OF RELEVANT FEATURES FROM MICROSCOPIC TRAFFIC DATA A Thesis by MATTHEW JAMES FIELDS Submitted to the Office of Graduate Studies of Texas A&M University in partial... Thesis by MATTHEW JAMES FIELDS Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Paul Nelson Committee Members...

  10. Facilitation of visual pattern recognition by extraction of relevant features from microscopic traffic data

    E-print Network

    Fields, Matthew James

    2008-10-10

    FACILITATION OF VISUAL PATTERN RECOGNITION BY EXTRACTION OF RELEVANT FEATURES FROM MICROSCOPIC TRAFFIC DATA A Thesis by MATTHEW JAMES FIELDS Submitted to the Office of Graduate Studies of Texas A&M University in partial... Thesis by MATTHEW JAMES FIELDS Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Paul Nelson Committee Members...

  11. EEG alpha rhythms and transient chromatic and achromatic pattern visual evoked potentials in children and adults

    Microsoft Academic Search

    Mei Ying Boon; Kar Ying Chan; Jaclyn Chiang; Rebecca Milston; Catherine Suttle

    2011-01-01

    Transient chromatic pattern visual evoked potentials (VEPs) have been found to be less repeatable in morphology in children\\u000a than in adults at low to moderate chromatic contrasts. The purpose of this study is to investigate whether low repeatability\\u000a of VEP components can be associated with high alpha power, in a comparison of alpha activity in children and adults. Transient\\u000a chromatic

  12. Eye Movements, Visual Search and Scene Memory, in an Immersive Virtual Environment

    PubMed Central

    Sullivan, Brian; Snyder, Kat; Ballard, Dana; Hayhoe, Mary

    2014-01-01

    Visual memory has been demonstrated to play a role in both visual search and attentional prioritization in natural scenes. However, it has been studied predominantly in experimental paradigms using multiple two-dimensional images. Natural experience, however, entails prolonged immersion in a limited number of three-dimensional environments. The goal of the present experiment was to recreate circumstances comparable to natural visual experience in order to evaluate the role of scene memory in guiding eye movements in a natural environment. Subjects performed a continuous visual-search task within an immersive virtual-reality environment over three days. We found that, similar to two-dimensional contexts, viewers rapidly learn the location of objects in the environment over time, and use spatial memory to guide search. Incidental fixations did not provide obvious benefit to subsequent search, suggesting that semantic contextual cues may often be just as efficient, or that many incidentally fixated items are not held in memory in the absence of a specific task. On the third day of the experience in the environment, previous search items changed in color. These items were fixated upon with increased probability relative to control objects, suggesting that memory-guided prioritization (or Surprise) may be a robust mechanisms for attracting gaze to novel features of natural environments, in addition to task factors and simple spatial saliency. PMID:24759905

  13. The Importance of the Eye Area in Face Identification Abilities and Visual Search Strategies in Persons with Asperger Syndrome

    ERIC Educational Resources Information Center

    Falkmer, Marita; Larsson, Matilda; Bjallmark, Anna; Falkmer, Torbjorn

    2010-01-01

    Partly claimed to explain social difficulties observed in people with Asperger syndrome, face identification and visual search strategies become important. Previous research findings are, however, disparate. In order to explore face identification abilities and visual search strategies, with special focus on the importance of the eye area, 24…

  14. Case study of visualizing global user download patterns using Google Earth and NASA World Wind

    SciTech Connect

    Zong, Ziliang; Job, Joshua; Zhang, Xuesong; Nijim, Mais; Qin, Xiao

    2012-10-09

    Geo-visualization is significantly changing the way we view spatial data and discover information. On the one hand, a large number of spatial data are generated every day. On the other hand, these data are not well utilized due to the lack of free and easily used data-visualization tools. This becomes even worse when most of the spatial data remains in the form of plain text such as log files. This paper describes a way of visualizing massive plain-text spatial data at no cost by utilizing Google Earth and NASAWorld Wind. We illustrate our methods by visualizing over 170,000 global download requests for satellite images maintained by the Earth Resources Observation and Science (EROS) Center of U.S. Geological Survey (USGS). Our visualization results identify the most popular satellite images around the world and discover the global user download patterns. The benefits of this research are: 1. assisting in improving the satellite image downloading services provided by USGS, and 2. providing a proxy for analyzing the hot spot areas of research. Most importantly, our methods demonstrate an easy way to geovisualize massive textual spatial data, which is highly applicable to mining spatially referenced data and information on a wide variety of research domains (e.g., hydrology, agriculture, atmospheric science, natural hazard, and global climate change).

  15. Examining perceptual and conceptual set biases in multiple-target visual search.

    PubMed

    Biggs, Adam T; Adamo, Stephen H; Dowd, Emma Wu; Mitroff, Stephen R

    2015-04-01

    Visual search is a common practice conducted countless times every day, and one important aspect of visual search is that multiple targets can appear in a single search array. For example, an X-ray image of airport luggage could contain both a water bottle and a gun. Searchers are more likely to miss additional targets after locating a first target in multiple-target searches, which presents a potential problem: If airport security officers were to find a water bottle, would they then be more likely to miss a gun? One hypothetical cause of multiple-target search errors is that searchers become biased to detect additional targets that are similar to a found target, and therefore become less likely to find additional targets that are dissimilar to the first target. This particular hypothesis has received theoretical, but little empirical, support. In the present study, we tested the bounds of this idea by utilizing "big data" obtained from the mobile application Airport Scanner. Multiple-target search errors were substantially reduced when the two targets were identical, suggesting that the first-found target did indeed create biases during subsequent search. Further analyses delineated the nature of the biases, revealing both a perceptual set bias (i.e., a bias to find additional targets with features similar to those of the first-found target) and a conceptual set bias (i.e., a bias to find additional targets with a conceptual relationship to the first-found target). These biases are discussed in terms of the implications for visual-search theories and applications for professional visual searchers. PMID:25678271

  16. Noun representation in AAC grid displays: visual attention patterns of people with traumatic brain injury.

    PubMed

    Brown, Jessica; Thiessen, Amber; Beukelman, David; Hux, Karen

    2015-03-01

    Clinicians supporting the communication of people with traumatic brain injury (TBI) must determine an efficient message representation method for augmentative and alternative communication (AAC) systems. Due to the frequency with which visual deficits occur following brain injury, some adults with TBI may have difficulty locating items on AAC displays. The purpose of this study was to identify aspects of graphic supports that increase efficiency of target-specific visual searches. Nine adults with severe TBI and nine individuals without neurological conditions located targets on static grids displaying one of three message representation methods. Data collected through eye tracking technology revealed significantly more efficient target location for icon-only grids than for text-only or icon-plus-text grids for both participant groups; no significant differences emerged between participant groups. PMID:25685881

  17. Visualizing a High Recall Search Strategy Output for Undergraduates in an Exploration Stage of Researching a Term Paper.

    ERIC Educational Resources Information Center

    Cole, Charles; Mandelblatt, Bertie; Stevenson, John

    2002-01-01

    Discusses high recall search strategies for undergraduates and how to overcome information overload that results. Highlights include word-based versus visual-based schemes; five summarization and visualization schemes for presenting information retrieval citation output; and results of a study that recommend visualization schemes geared toward…

  18. Neuronal dynamics of bottom-up and top-down processes in area V4 of macaque monkeys performing a visual search

    Microsoft Academic Search

    Tadashi Ogawa; Hidehiko Komatsu

    2006-01-01

    Visual selection is thought to be guided by both bottom-up intrinsic visual saliency and top-down visual attention. We examined how the relative importance of each of these processes dynamically changes over the course of a visual search in area V4 of two macaque monkeys. The animals were trained to perform a multidimensional visual search task in which a search array

  19. Timescales of Multineuronal Activity Patterns Reflect Temporal Structure of Visual Stimuli

    PubMed Central

    Jurju?, Ovidiu F.; Nikoli?, Danko; Singer, Wolf; Yu, Shan; Havenith, Martha N.; Mure?an, Raul C.

    2011-01-01

    The investigation of distributed coding across multiple neurons in the cortex remains to this date a challenge. Our current understanding of collective encoding of information and the relevant timescales is still limited. Most results are restricted to disparate timescales, focused on either very fast, e.g., spike-synchrony, or slow timescales, e.g., firing rate. Here, we investigated systematically multineuronal activity patterns evolving on different timescales, spanning the whole range from spike-synchrony to mean firing rate. Using multi-electrode recordings from cat visual cortex, we show that cortical responses can be described as trajectories in a high-dimensional pattern space. Patterns evolve on a continuum of coexisting timescales that strongly relate to the temporal properties of stimuli. Timescales consistent with the time constants of neuronal membranes and fast synaptic transmission (5–20 ms) play a particularly salient role in encoding a large amount of stimulus-related information. Thus, to faithfully encode the properties of visual stimuli the brain engages multiple neurons into activity patterns evolving on multiple timescales. PMID:21346812

  20. Searching for intellectual turning points: Progressive knowledge domain visualization

    E-print Network

    Indiana University

    network. The method provides a promising way to simplify otherwise cognitively demanding tasks to a search, this is an ambitious and challenging quest because of the scale, diversity, and dynamic nature of scientific networks

  1. Patent semantics : analysis, search and visualization of large text corpora

    E-print Network

    Lucas, Christopher G

    2004-01-01

    Patent Semantics is system for processing text documents by extracting features capturing their semantic content, and searching, clustering, and relating them by those same features. It is set apart from existing methodologies ...

  2. Visual information and multi-joint coordination patterns in one-leg stance.

    PubMed

    Wang, Zheng; Molenaar, Peter C M; Challis, John H; Jordan, Kimberlee; Newell, Karl M

    2014-03-01

    This study examined the influence of visual information on the multi-joint coordination patterns in maintaining one-leg stance. 12 participants stood still on their left leg for two 1 min trials with and without visual information. The multi-joint coordination patterns in the frontal plane were examined using a frequency domain principal component analysis (PCAf) on 14 joint angular motion time series. The factor loading spectra of PC1 showed two distinct multi-joint postural coordination strategies that relate to the mechanical constraints on balance identified by Hof (2007) [7]. The more prevalent strategy was the coordination of the left ankle-left knee or the left ankle only motion that is related to the "moving the center of pressure" strategy. A 2nd multi-joint coordination strategy showed larger factor loading of the trunk and upper limbs (i.e., shoulders and elbows) in addition to the left ankle implying the role of the upper limbs to generate "counter-rotational torque against the sway of the center of mass (COM)". With eyes open, the participants predominantly utilized the 1st strategy to maintain balance but switched to the 2nd strategy when visual information was not available during the stance. The role of visual information in determining the prevalence of two dominant multi-joint coordination kinematic patterns in one-leg stance reflects the redundant and emergent properties of the postural control system that channel the biomechanical constraints on balance arising from the interaction of the task, environment and the individual. PMID:24388780

  3. Target grouping in visual search for multiple digits.

    PubMed

    Sobel, Kenith V; Puri, Amrita M; Hogan, Jared

    2015-01-01

    In four experiments in which participants searched for multiple target digits we hypothesized that search should be fastest when the targets are arranged closely together on the number line without any intervening distractor digits, i.e., the targets form a contiguous and coherent group. In Experiment 1 search performance was better for targets defined by numerical magnitude than parity (i.e., evenness); this result supports our hypothesis but could also be due to the linear separability of targets from distractors or the numerical distance between them. Experiment 2 controlled for target-distractor linear separability and numerical distance, yielding faster search when targets were surrounded by distractors on the number line than when they surrounded distractors. This result is consistent with target contiguity and coherence but also with grouping by similarity of target shapes. Experiment 3 controlled for all three alternative explanations (linear separability, numerical distance, and shape similarity) and search performance was better for contiguous targets than separated targets. In Experiment 4 search performance was better for a coherent target group than one with intervening distractors. Of the possibilities we considered, only the hypothesis based on the contiguity and coherence of the target group on the number line can account for the results from all four experiments. PMID:25156757

  4. Spatial patterns of visual cortical fast EEG during conditioned reflex in a rhesus monkey.

    PubMed

    Freeman, W J; van Dijk, B W

    1987-10-01

    A preliminary assay was made of the existence of time-space coherence patterns of fast EEG activity in the visual cortex of a Rhesus monkey. The primary intent of the present study was to evaluate the similarities and differences in relation to the olfactory bulb, where such coherences have been described and have been demonstrated to be associated with behaviour. Segments 1.5 s in duration were recorded simultaneously without averaging from 16 to 35 subdural electrodes fixed over the left occipital lobe in an array 3.6 cm X 2.8 cm. Each segment was taken during the delivery of a visual conditioned stimulus (CS) and the performance of a conditioned response (CR) by a well-trained Rhesus monkey. The EEGs appeared chaotic with irregular bursts lasting 75-200 ms, resembling those in the olfactory EEG but with lower peak frequencies. Fourier spectra showed broad distributions of power resembling '1/f noise' with multiple peaks in the range of 20-40 Hz. Time intervals were selected where coherent activity seemed to be present at a number of electrodes. A dominant component waveform that was common to all channels was extracted by principal components analysis (PCA) of each segment. The distribution of the power of this component across the electrodes (the factor loadings) was used to describe the spatial pattern of the coherent cortical activity. Statistical analyses suggested that different patterns could be associated to the CS and the CR, as has been found in the olfactory system. These patterns remained stable over a 6 week recording interval. The patterns can be better discriminated, when the factor loadings of each channel are normalized to zero mean and unit variance, to discard a basic pattern of power distribution, which may reflect anatomical and electrode positioning factors that are related to behavioral information processing by the cortex. The wide spatial distribution of the common patterns found suggests that EEG patterns that manifest differing states of the visual cortex may also be accessible with scalp electrodes. PMID:3676788

  5. Optimization of boiling water reactor control rod patterns using linear search

    Microsoft Academic Search

    T. Kiguchi; K. Doi; T. Fikuzaki; B. Frogner; C. Lin; A. B. Long

    1984-01-01

    A computer program for searching the optimal control rod pattern has been developed. The program is able to find a control rod pattern where the resulting power distribution is optimal in the sense that it is the closest to the desired power distribution, and it satisfies all operational constraints. The search procedure consists of iterative uses of two steps: sensitivity

  6. Price Information Patterns in Web Search Advertising: An Empirical Case Study on Accommodation Industry

    E-print Network

    Pei, Jian

    empirical findings shed new light on how to effectively manage price information in search advertisingPrice Information Patterns in Web Search Advertising: An Empirical Case Study on Accommodation--Unlike advertising in traditional media, web search advertising content can be easily customized with little cost

  7. Children with Fetal Alcohol Syndrome and Fetal Alcohol Effects: Patterns of Performance on IQ and Visual Motor Ability.

    ERIC Educational Resources Information Center

    Kopera-Frye, Karen; Zielinski, Sharon

    This study explored relationships between intelligence and visual motor ability and patterns of impairment of visual motor ability in children prenatally affected by alcohol. Fourteen children (mean age 8.2 years) diagnosed with fetal alcohol syndrome (FAS) and 50 children with possible fetal alcohol effects (FAE) were assessed with the Bender…

  8. Differential Roles of the Fan-Shaped Body and the Ellipsoid Body in "Drosophila" Visual Pattern Memory

    ERIC Educational Resources Information Center

    Pan, Yufeng; Zhou, Yanqiong; Guo, Chao; Gong, Haiyun; Gong, Zhefeng; Liu, Li

    2009-01-01

    The central complex is a prominent structure in the "Drosophila" brain. Visual learning experiments in the flight simulator, with flies with genetically altered brains, revealed that two groups of horizontal neurons in one of its substructures, the fan-shaped body, were required for "Drosophila" visual pattern memory. However, little is known…

  9. Implications of sustained and transient channels for theories of visual pattern masking, saccadic suppression, and information processing

    Microsoft Academic Search

    Bruno G. Breitmeyer; Leo Ganz

    1976-01-01

    Reviews the visual masking literature in the context of known neurophysiological and psychophysical properties of the visual system's spatiotemporal response. The literature indicates that 3 consistent and typical pattern masking effects––(a) Type B forward or paracontrast, (b) Type B backward or metacontrast, and (c) Type A forward and backward––can be explained in terms of 3 simple sensory processes. It is

  10. What Are the Shapes of Response Time Distributions in Visual Search?

    ERIC Educational Resources Information Center

    Palmer, Evan M.; Horowitz, Todd S.; Torralba, Antonio; Wolfe, Jeremy M.

    2011-01-01

    Many visual search experiments measure response time (RT) as their primary dependent variable. Analyses typically focus on mean (or median) RT. However, given enough data, the RT distribution can be a rich source of information. For this paper, we collected about 500 trials per cell per observer for both target-present and target-absent displays…

  11. Visual Search Asymmetries within Color-Coded and Intensity-Coded Displays

    ERIC Educational Resources Information Center

    Yamani, Yusuke; McCarley, Jason S.

    2010-01-01

    Color and intensity coding provide perceptual cues to segregate categories of objects within a visual display, allowing operators to search more efficiently for needed information. Even within a perceptually distinct subset of display elements, however, it may often be useful to prioritize items representing urgent or task-critical information.…

  12. Low Target Prevalence Is a Stubborn Source of Errors in Visual Search Tasks

    ERIC Educational Resources Information Center

    Wolfe, Jeremy M.; Horowitz, Todd S.; Van Wert, Michael J.; Kenner, Naomi M.; Place, Skyler S.; Kibbi, Nour

    2007-01-01

    In visual search tasks, observers look for targets in displays containing distractors. Likelihood that targets will be missed varies with target prevalence, the frequency with which targets are presented across trials. Miss error rates are much higher at low target prevalence (1%-2%) than at high prevalence (50%). Unfortunately, low prevalence is…

  13. Visual Search for Object Orientation Can Be Modulated by Canonical Orientation

    ERIC Educational Resources Information Center

    Ballaz, Cecile; Boutsen, Luc; Peyrin, Carole; Humphreys, Glyn W.; Marendaz, Christian

    2005-01-01

    The authors studied the influence of canonical orientation on visual search for object orientation. Displays consisted of pictures of animals whose axis of elongation was either vertical or tilted in their canonical orientation. Target orientation could be either congruent or incongruent with the object's canonical orientation. In Experiment 1,…

  14. Visual Search for Object Orientation Can Be Modulated by Canonical Orientation

    Microsoft Academic Search

    Cécile Ballaz; Luc Boutsen; Carole Peyrin; Glyn W. Humphreys; Christian Marendaz

    2005-01-01

    The authors studied the influence of canonical orientation on visual search for object orientation. Displays consisted of pictures of animals whose axis of elongation was either vertical or tilted in their canonical orientation. Target orientation could be either congruent or incongruent with the object's canonical orientation. In Experiment 1, vertical canonical targets were detected faster when they were tilted (incongruent)

  15. Masked target transform volume clutter metric for human observer visual search modeling

    Microsoft Academic Search

    Richard Kirk Moore

    2009-01-01

    The Night Vision and Electronic Sensors Directorate (NVESD) develops an imaging system performance model to aid in the design and comparison of imaging systems for military use. It is intended to approximate visual task performance for a typical human observer with an imaging system of specified optical, electrical, physical, and environmental parameters. When modeling search performance, the model currently uses

  16. Low Target Prevalence Is a Stubborn Source of Errors in Visual Search Tasks

    E-print Network

    Low Target Prevalence Is a Stubborn Source of Errors in Visual Search Tasks Jeremy M. Wolfe and Todd S. Horowitz Brigham and Women's Hospital and Harvard Medical School Michael J. Van Wert, Naomi M with target prevalence, the frequency with which targets are presented across trials. Miss error rates

  17. "Self pop-out": agency enhances self-recognition in visual search.

    PubMed

    Salomon, R; Lim, M; Kannape, O; Llobera, J; Blanke, O

    2013-07-01

    In real-life situations, we are often required to recognize our own movements among movements originating from other people. In social situations, these movements are often correlated (for example, when dancing or walking with others) adding considerable difficulty to self-recognition. Studies from visual search have shown that visual attention can selectively highlight specific features to make them more salient. Here, we used a novel visual search task employing virtual reality and motion tracking to test whether visual attention can use efferent information to enhance self-recognition of one's movements among four or six moving avatars. Active movements compared to passive movements allowed faster recognition of the avatar moving like the subject. Critically, search slopes were flat for the active condition but increased for passive movements, suggesting efficient search for active movements. In a second experiment, we tested the effects of using the participants' own movements temporally delayed as distractors in a self-recognition discrimination task. We replicated the results of the first experiment with more rapid self-recognition during active trials. Importantly, temporally delayed distractors increased reaction times despite being more perceptually different than the spatial distractors. The findings demonstrate the importance of agency in self-recognition and self-other discrimination from movement in social settings. PMID:23665753

  18. Visual search in children and adults: top-down and bottom-up mechanisms.

    PubMed

    Donnelly, Nick; Cave, Kyle; Greenway, Rebecca; Hadwin, Julie A; Stevenson, Jim; Sonuga-Barke, Edmund

    2007-01-01

    Three experiments investigated visual search for targets that differed from distractors in colour, size, or orientation. In one condition the target was defined by a conjunction of these features, while in the other condition the target was the odd one out. In all experiments, 6-7- and 9-10-year-old children were compared with young adults. Experiment 1 showed that children's search differed from adults' search in two ways. In conjunction searches children searched more slowly and took longer to reject trials when no target was present. In the odd-one-out experiments, 6-7-year-old children were slower to respond to size targets than to orientation targets, and slower for orientation targets than for colour targets. Both the other groups showed no difference in their rate of responding to colour and orientation. Experiments 2 and 3 highlighted that these results were not a function of either differential density across set sizes (Experiment 2) or discriminability of orientation and colour (Experiment 3). Across all three experiments, the results of both conjunction and odd-one-out searches highlighted a development in visual search from middle to late childhood. PMID:17162511

  19. A Globally Convergent Augmented Lagrangian Pattern Search Algorithm for Optimization with General Constraints and Simple Bounds

    NASA Technical Reports Server (NTRS)

    Lewis, Robert Michael; Torczon, Virginia

    1998-01-01

    We give a pattern search adaptation of an augmented Lagrangian method due to Conn, Gould, and Toint. The algorithm proceeds by successive bound constrained minimization of an augmented Lagrangian. In the pattern search adaptation we solve this subproblem approximately using a bound constrained pattern search method. The stopping criterion proposed by Conn, Gould, and Toint for the solution of this subproblem requires explicit knowledge of derivatives. Such information is presumed absent in pattern search methods; however, we show how we can replace this with a stopping criterion based on the pattern size in a way that preserves the convergence properties of the original algorithm. In this way we proceed by successive, inexact, bound constrained minimization without knowing exactly how inexact the minimization is. So far as we know, this is the first provably convergent direct search method for general nonlinear programming.

  20. Saliency, attention, and visual search: An information theoretic approach

    E-print Network

    , or in considering the control of focal cortical processing. Consideration of fixational eye movements necessarily, and the second characterized by bottom-up stimulus-driven factors governed by the specific nature of the visual stimulus. The importance of the former of these categories is well documented and perhaps most prominently

  1. Gene prediction by pattern recognition and homology search

    SciTech Connect

    Xu, Y.; Uberbacher, E.C.

    1996-05-01

    This paper presents an algorithm for combining pattern recognition-based exon prediction and database homology search in gene model construction. The goal is to use homologous genes or partial genes existing in the database as reference models while constructing (multiple) gene models from exon candidates predicted by pattern recognition methods. A unified framework for gene modeling is used for genes ranging from situations with strong homology to no homology in the database. To maximally use the homology information available, the algorithm applies homology on three levels: (1) exon candidate evaluation, (2) gene-segment construction with a reference model, and (3) (complete) gene modeling. Preliminary testing has been done on the algorithm. Test results show that (a) perfect gene modeling can be expected when the initial exon predictions are reasonably good and a strong homology exists in the database; (b) homology (not necessarily strong) in general helps improve the accuracy of gene modeling; (c) multiple gene modeling becomes feasible when homology exists in the database for the involved genes.

  2. A reference web architecture and patterns for real-time visual analytics on large streaming data

    NASA Astrophysics Data System (ADS)

    Kandogan, Eser; Soroker, Danny; Rohall, Steven; Bak, Peter; van Ham, Frank; Lu, Jie; Ship, Harold-Jeffrey; Wang, Chun-Fu; Lai, Jennifer

    2013-12-01

    Monitoring and analysis of streaming data, such as social media, sensors, and news feeds, has become increasingly important for business and government. The volume and velocity of incoming data are key challenges. To effectively support monitoring and analysis, statistical and visual analytics techniques need to be seamlessly integrated; analytic techniques for a variety of data types (e.g., text, numerical) and scope (e.g., incremental, rolling-window, global) must be properly accommodated; interaction, collaboration, and coordination among several visualizations must be supported in an efficient manner; and the system should support the use of different analytics techniques in a pluggable manner. Especially in web-based environments, these requirements pose restrictions on the basic visual analytics architecture for streaming data. In this paper we report on our experience of building a reference web architecture for real-time visual analytics of streaming data, identify and discuss architectural patterns that address these challenges, and report on applying the reference architecture for real-time Twitter monitoring and analysis.

  3. VisualRank: applying PageRank to large-scale image search.

    PubMed

    Jing, Yushi; Baluja, Shumeet

    2008-11-01

    Because of the relative ease in understanding and processing text, commercial image-search systems often rely on techniques that are largely indistinguishable from text-search. Recently, academic studies have demonstrated the effectiveness of employing image-based features to provide alternative or additional signals. However, it remains uncertain whether such techniques will generalize to a large number of popular web queries, and whether the potential improvement to search quality warrants the additional computational cost. In this work, we cast the image-ranking problem into the task of identifying "authority" nodes on an inferred visual similarity graph and propose VisualRank to analyze the visual link structures among images. The images found to be "authorities" are chosen as those that answer the image-queries well. To understand the performance of such an approach in a real system, we conducted a series of large-scale experiments based on the task of retrieving images for 2000 of the most popular products queries. Our experimental results show significant improvement, in terms of user satisfaction and relevancy, in comparison to the most recent Google Image Search results. Maintaining modest computational cost is vital to ensuring that this procedure can be used in practice; we describe the techniques required to make this system practical for large scale deployment in commercial search engines. PMID:18787237

  4. On the Role of Consonants and Vowels in Visual-Word Processing: Evidence with a Letter Search Paradigm

    ERIC Educational Resources Information Center

    Acha, Joana; Perea, Manuel

    2010-01-01

    Prior research has shown that the search function in the visual letter search task may reflect the regularities of the orthographic structure of a given script. In the present experiment, we examined whether the search function of letter detection was sensitive to consonant-vowel status of a pre-cued letter. Participants had to detect the…

  5. Incidental Learning Speeds Visual Search by Lowering Response Thresholds, Not by Improving Efficiency: Evidence from Eye Movements

    ERIC Educational Resources Information Center

    Hout, Michael C.; Goldinger, Stephen D.

    2012-01-01

    When observers search for a target object, they incidentally learn the identities and locations of "background" objects in the same display. This learning can facilitate search performance, eliciting faster reaction times for repeated displays. Despite these findings, visual search has been successfully modeled using architectures that maintain no…

  6. Epistemic Beliefs, Online Search Strategies, and Behavioral Patterns While Exploring Socioscientific Issues

    NASA Astrophysics Data System (ADS)

    Hsu, Chung-Yuan; Tsai, Meng-Jung; Hou, Huei-Tse; Tsai, Chin-Chung

    2014-06-01

    Online information searching tasks are usually implemented in a technology-enhanced science curriculum or merged in an inquiry-based science curriculum. The purpose of this study was to examine the role students' different levels of scientific epistemic beliefs (SEBs) play in their online information searching strategies and behaviors. Based on the measurement of an SEB survey, 42 undergraduate and graduate students in Taiwan were recruited from a pool of 240 students and were divided into sophisticated and naïve SEB groups. The students' self-perceived online searching strategies were evaluated by the Online Information Searching Strategies Inventory, and their search behaviors were recorded by screen-capture videos. A sequential analysis was further used to analyze the students' searching behavioral patterns. The results showed that those students with more sophisticated SEBs tended to employ more advanced online searching strategies and to demonstrate a more metacognitive searching pattern.

  7. Visualizing the Entire Cortical Myelination Pattern in Marmosets with Magnetic Resonance Imaging

    PubMed Central

    Bock, Nicholas A.; Kocharyan, Ara; Liu, Junjie V.; Silva, Afonso C.

    2009-01-01

    Myeloarchitecture, the pattern of myelin density across the cerebral cortex, has long been visualized in histological sections to identify distinct anatomical areas of the cortex. In humans, two-dimensional (2D) magnetic resonance imaging (MRI) has been used to visualize myeloarchitecture in select areas of the cortex, such as the stripe of Gennari in the primary visual cortex and Heschl’s gyrus in the primary auditory cortex. Here, we investigated the use of MRI contrast based on longitudinal relaxation time (T1) to visualize myeloarchitecture in vivo over the entire cortex of the common marmoset (Callithrix jacchus), a small non-human primate that is becoming increasingly important in neuroscience and neurobiology research. Using quantitative T1 mapping, we found that T1 at 7 Tesla in a cortical region with a high myelin content was 15% shorter than T1 in a region with a low myelin content. To maximize this T1 contrast for imaging cortical myelination patterns, we optimized a magnetization-prepared rapidly-acquired gradient echo (MP-RAGE) sequence. In whole-brain, 3D T1-weighted images made in vivo with the sequence, we identified six major cortical areas with high myelination and confirmed the results with histological sections stained for myelin. We also identified several subtle features of myeloarchitecture, showing the sensitivity of our technique. The ability to image myeloarchitecture over the entire cortex may prove useful in studies of longitudinal changes of the topography of the cortex associated with development and neuronal plasticity, as well as for guiding and confirming the location of functional measurements. PMID:19737577

  8. Adaptation in the Visual Cortex: Influence of Membrane Trajectory and Neuronal Firing Pattern on Slow Afterpotentials

    PubMed Central

    Descalzo, Vanessa F.; Gallego, Roberto; Sanchez-Vives, Maria V.

    2014-01-01

    The input/output relationship in primary visual cortex neurons is influenced by the history of the preceding activity. To understand the impact that membrane potential trajectory and firing pattern has on the activation of slow conductances in cortical neurons we compared the afterpotentials that followed responses to different stimuli evoking similar numbers of action potentials. In particular, we compared afterpotentials following the intracellular injection of either square or sinusoidal currents lasting 20 seconds. Both stimuli were intracellular surrogates of different neuronal responses to prolonged visual stimulation. Recordings from 99 neurons in slices of visual cortex revealed that for stimuli evoking an equivalent number of spikes, sinusoidal current injection activated a slow afterhyperpolarization of significantly larger amplitude (8.5±3.3 mV) and duration (33±17 s) than that evoked by a square pulse (6.4±3.7 mV, 28±17 s; p<0.05). Spike frequency adaptation had a faster time course and was larger during plateau (square pulse) than during intermittent (sinusoidal) depolarizations. Similar results were obtained in 17 neurons intracellularly recorded from the visual cortex in vivo. The differences in the afterpotentials evoked with both protocols were abolished by removing calcium from the extracellular medium or by application of the L-type calcium channel blocker nifedipine, suggesting that the activation of a calcium-dependent current is at the base of this afterpotential difference. These findings suggest that not only the spikes, but the membrane potential values and firing patterns evoked by a particular stimulation protocol determine the responses to any subsequent incoming input in a time window that spans for tens of seconds to even minutes. PMID:25380063

  9. Underwater and above-water search patterns of an Arctic seabird: reduced searching at small spatiotemporal scales

    Microsoft Academic Search

    Kyle Hamish Elliott; Roger D. Bull; Anthony J. Gaston; Gail K. Davoren

    2009-01-01

    How predators vary search patterns in response to prey predictability is poorly known. For example, marine invertebrates may\\u000a be predictable but of low energy value, while fish may be of higher energy value but unpredictable at large (pelagic schools)\\u000a or small (solitary benthics) spatial scales. We investigated the search patterns of the thick-billed murre (Uria lomvia), an Arctic seabird feeding

  10. Initial Scene Representations Facilitate Eye Movement Guidance in Visual Search

    ERIC Educational Resources Information Center

    Castelhano, Monica S.; Henderson, John M.

    2007-01-01

    What role does the initial glimpse of a scene play in subsequent eye movement guidance? In 4 experiments, a brief scene preview was followed by object search through the scene via a small moving window that was tied to fixation position. Experiment 1 demonstrated that the scene preview resulted in more efficient eye movements compared with a…

  11. Informed visual search: Combining attention and object recognition

    Microsoft Academic Search

    Per-erik Forssén; David Meger; Kevin Lai; Scott Helmer; James J. Little; David G. Lowe

    2008-01-01

    This paper studies the sequential object recogni- tion problem faced by a mobile robot searching for specific objects within a cluttered environment. In contrast to current state-of-the-art object recognition solutions which are evaluated on databases of static images, the system described in this paper employs an active strategy based on identifying potential objects using an attention mechanism and planning to

  12. Efficient Visual Search of Videos Cast as Text Retrieval

    Microsoft Academic Search

    Josef Sivic; Andrew Zisserman

    2009-01-01

    We describe an approach to object retrieval which searches for and localizes all the occurrences of an object in a video, given a query image of the object. The object is represented by a set of viewpoint invariant region descriptors so that recognition can proceed successfully despite changes in viewpoint, illumination and partial occlusion. The temporal continuity of the video

  13. Heuristic Search and Information Visualization Methods for School Redistricting

    Microsoft Academic Search

    Marie Desjardins; Blazej Bulka; Ryan Carr; Andrew Hunt; Priyang Rathod; Penny Rheingans

    2006-01-01

    We describe an application of AI search and information visu- alization techniques to the problem of school redistricting, in which students are assigned to home schools within a county or school district. This is a multicriteria optimization prob- lem in which competing objectives must be considered, such as school capacity, busing costs, and socioeconomic distri- bution. Because of the complexity

  14. Precue effects in visual search: Data or resource limited?

    Microsoft Academic Search

    Ronald A. Kinchla; Zhe Chen; Denise Evert

    1995-01-01

    Precuing an observer as to where a target is more likely to occur in a subsequent visual array can increase the detectability\\u000a (d?) of a target at that location. This is often attributed to the observer’s increased allocation of some limited cognitive\\u000a resource (“attention”) to the cued location. Two experiments are reported which are difficult to interpret in this way

  15. Ocular dominance patterns in mammalian visual cortex: A wire length minimization approach

    E-print Network

    Dmitri B. Chklovskii; Alexei A. Koulakov

    1999-06-14

    We propose a theory for ocular dominance (OD) patterns in mammalian primary visual cortex. This theory is based on the premise that OD pattern is an adaptation to minimize the length of intra-cortical wiring. Thus we can understand the existing OD patterns by solving a wire length minimization problem. We divide all the neurons into two classes: left-eye dominated and right-eye dominated. We find that segregation of neurons into monocular regions reduces wire length if the number of connections with the neurons of the same class differs from that with the other class. The shape of the regions depends on the relative fraction of neurons in the two classes. If the numbers are close we find that the optimal OD pattern consists of interdigitating stripes. If one class is less numerous than the other, the optimal OD pattern consists of patches of the first class neurons in the sea of the other class neurons. We predict the transition from stripes to patches when the fraction of neurons dominated by the ipsilateral eye is about 40%. This prediction agrees with the data in macaque and Cebus monkeys. This theory can be applied to other binary cortical systems.

  16. A wire length minimization approach to ocular dominance patterns in mammalian visual cortex

    NASA Astrophysics Data System (ADS)

    Chklovskii, Dmitri B.; Koulakov, Alexei A.

    2000-09-01

    The primary visual area (V1) of the mammalian brain is a thin sheet of neurons. Because each neuron is dominated by either right or left eye one can treat V1 as a binary mixture of neurons. The spatial arrangement of neurons dominated by different eyes is known as the ocular dominance (OD) pattern. We propose a theory for OD patterns based on the premise that they are evolutionary adaptations to minimize the length of intra-cortical connections. Thus, the existing OD patterns are obtained by solving a wire length minimization problem. We divide all the neurons into two classes: right- and left-eye dominated. We find that if the number of connections of each neuron with the neurons of the same class differs from that with the other class, the segregation of neurons into monocular regions indeed reduces the wire length. The shape of the regions depends on the relative number of neurons in the two classes. If both classes are equally represented we find that the optimal OD pattern consists of alternating stripes. If one class is less numerous than the other, the optimal OD pattern consists of patches of the underrepresented (ipsilateral) eye dominated neurons surrounded by the neurons of the other class. We predict the transition from stripes to patches when the fraction of neurons dominated by the ipsilateral eye is about 40%. This prediction agrees with the data in macaque and Cebus monkeys. Our theory can be applied to other binary cortical systems.

  17. Visual Servoing: A technology in search of an application

    SciTech Connect

    Feddema, J.T.

    1994-05-01

    Considerable research has been performed on Robotic Visual Servoing (RVS) over the past decade. Using real-time visual feedback, researchers have demonstrated that robotic systems can pick up moving parts, insert bolts, apply sealant, and guide vehicles. With the rapid improvements being made in computing and image processing hardware, one would expect that every robot manufacturer would have a RVS option by the end of the 1990s. So why aren`t the Fanucs, ABBs, Adepts, and Motomans of the world investing heavily in RVS? I would suggest four seasons: cost, complexity, reliability, and lack of demand. Solutions to the first three are approaching the point where RVS could be commercially available; however, the lack of demand is keeping RVS from becoming a reality in the near future. A new set of applications is needed to focus near term RVS development. These must be applications which currently do not have solutions. Once developed and working in one application area, the technology is more likely to quickly spread to other areas. DOE has several applications that are looking for technological solutions, such as agile weapons production, weapons disassembly, decontamination and dismantlement of nuclear facilities, and hazardous waste remediation. This paper will examine a few of these areas and suggest directions for application-driven visual servoing research.

  18. Masked target transform volume clutter metric for human observer visual search modeling

    NASA Astrophysics Data System (ADS)

    Moore, Richard Kirk

    The Night Vision and Electronic Sensors Directorate (NVESD) develops an imaging system performance model to aid in the design and comparison of imaging systems for military use. It is intended to approximate visual task performance for a typical human observer with an imaging system of specified optical, electrical, physical, and environmental parameters. When modeling search performance, the model currently uses only target size and target-to-background contrast to describe a scene. The presence or absence of other non-target objects and textures in the scene also affect search performance, but NVESD's targeting task performance metric based time limited search model (TTP/TLS) does not currently account for them explicitly. Non-target objects in a scene that impact search performance are referred to as clutter. A universally accepted mathematical definition of clutter does not yet exist. Researchers have proposed a number of clutter metrics based on very different methods, but none account for display geometry or the varying spatial frequency sensitivity of the human visual system. After a review of the NVESD search model, properties of the human visual system, and a literature review of clutter metrics, the new masked target transform volume clutter metric will be presented. Next the results of an experiment designed to show performance variation due to clutter alone will be presented. Then, the results of three separate perception experiments using real or realistic search imagery will be used to show that the new clutter metric better models human observer search performance than the current NVESD model or any of the reviewed clutter metrics.

  19. Memories in clay paste of vibration and flow: their visualization as crack patterns

    NASA Astrophysics Data System (ADS)

    Nakahara, A.; Matsuo, Y.

    2009-12-01

    We experimentally find that a clay paste (densely packed disk-like colloidal suspension with plasticity) has memories of external mechanical fields it suffered, such as vibration and flow. These memories are sustained as microscopically anisotropic network structures of colloidal particles. By drying these pastes, memories in pastes can be visualized as macroscopically anisotropic crack patterns. When a clay paste is vibrated before drying, it remembers a direction of vibration even after we stop vibration, and the direction of cracks which appears at the drying process becomes perpendicular to the direction of the vibration. That is, we get a lamellar crack pattern, the direction of which is perpendicular to the direction of the initial vibration [1]. On the other hand, when a clay paste is vibrated so strongly that it becomes fluidized, it comes to remember a flow direction, and the direction of the resultant crack pattern becomes parallel to the direction of the flow. That is, we can imprint flow pattern into clay paste as memory [2]. There are many applications which can be enabled by using memory effects of paste. One is a control on morphology of future crack patterns. By using the memory effect of paste, we can control and make various crack patterns, such as cellular, lamellar, radial, ring, and spiral, shown in figures [3]. The other application becomes very important in the field of geoscience. Since clay paste remembers external mechanical fields it suffered, such as vibration and flow, its memory effect becomes a strong tool to know what happened in the past in a history of earth. [1] A. Nakahara and Y. Matsuo, J. Phys. Soc, Jpn., 74, 1362 (2005). [2] A. Nakahara and Y. Matsuo, Phys. Rev. E 74, 045102 (2006). [3] Physics Today 60: no. 9, p. 116 (2007). Radial and spiral crack patterns

  20. Global statistical regularities modulate the speed of visual search in patients with focal attentional deficits

    PubMed Central

    Lanzoni, Lucilla; Melcher, David; Miceli, Gabriele; Corbett, Jennifer E.

    2014-01-01

    There is growing evidence that the statistical properties of ensembles of similar objects are processed in a qualitatively different manner than the characteristics of individual items. It has recently been proposed that these types of perceptual statistical representations are part of a strategy to complement focused attention in order to circumvent the visual system’s limited capacity to represent more than a few individual objects in detail. Previous studies have demonstrated that patients with attentional deficits are nonetheless sensitive to these sorts of statistical representations. Here, we examined how such global representations may function to aid patients in overcoming focal attentional limitations by manipulating the statistical regularity of a visual scene while patients performed a search task. Three patients previously diagnosed with visual neglect searched for a target Gabor tilted to the left or right of vertical in displays of horizontal distractor Gabors. Although the local sizes of the distractors changed on every trial, the mean size remained stable for several trials. Patients made faster correct responses to targets in neglected regions of the visual field when global statistics remained constant over several trials, similar to age-matched controls. Given neglect patients’ attentional deficits, these results suggest that stable perceptual representations of global statistics can establish a context to speed search without the need to represent individual elements in detail. PMID:24971066

  1. No attentional capture for simple visual search: evidence for a dual-route account.

    PubMed

    Chan, Louis K H; Hayward, William G

    2014-12-01

    An enduring question in visual attention research is whether unattended objects are subject to perceptual processing. The traditional view suggests that, whereas focal attention is required for the processing of complex features or for individuating objects, it is not required for detecting basic features. However, other models suggest that detecting basic features may be no different from object identification and also require focal attention. In the present study, we approach this problem by measuring the effect of attentional capture in simple and compound visual search tasks. To make sure measurements did not reflect strategic components of the tasks, we measured accuracy with brief displays. Results show that attentional capture influenced only compound but not basic feature searches, suggestive of a distinction between attentional requirements of the 2 tasks. We discuss our findings, together with recent results of top-down word cue effects and dimension-specific intertrial effects, in terms of the dual-route account for visual search, which suggests that the task that is being completed determines whether search is based on attentive or preattentive mechanisms. PMID:25181370

  2. Visual search performance of patients with vision impairment: Effect of JPEG image enhancement

    PubMed Central

    Luo, Gang; Satgunam, PremNandhini; Peli, Eli

    2012-01-01

    Purpose To measure natural image search performance in patients with central vision impairment. To evaluate the performance effect for a JPEG based image enhancement technique using the visual search task. Method 150 JPEG images were presented on a touch screen monitor in either an enhanced or original version to 19 patients (visual acuity 0.4 to 1.2 logMAR, 6/15 to 6/90, 20/50 to 20/300) and 7 normally sighted controls (visual acuity ?0.12 to 0.1 logMAR, 6/4.5 to 6/7.5, 20/15 to 20/25). Each image fell into one of three categories: faces, indoors, and collections. The enhancement was realized by moderately boosting a mid-range spatial frequency band in the discrete cosine transform (DCT) coefficients of the image luminance component. Participants pointed to an object in a picture that matched a given target displayed at the upper-left corner of the monitor. Search performance was quantified by the percentage of correct responses, the median search time of correct responses, and an “integrated performance” measure – the area under the curve of cumulative correct response rate over search time. Results Patients were able to perform the search tasks but their performance was substantially worse than the controls. Search performances for the 3 image categories were significantly different (p?0.001) for all the participants, with searching for faces being the most difficult. When search time and correct response were analyzed separately, the effect of enhancement led to increase in one measure but decrease in another for many patients. Using the integrated performance, it was found that search performance declined with decrease in acuity (p=0.005). An improvement with enhancement was found mainly for the patients whose acuity ranged from 0.4 to 0.8 logMAR (6/15 to 6/38, 20/50 to 20/125). Enhancement conferred a small but significant improvement in integrated performance for indoor and collection images (p=0.025) in the patients. Conclusion Search performance for natural images can be measured in patients with impaired vision to evaluate the effect of image enhancement. Patients with moderate vision loss might benefit from the moderate level of enhancement used here. PMID:22540926

  3. Case of acute zonal occult outer retinopathy with abnormal pattern visual evoked potentials.

    PubMed

    Chai, Yuzhu; Yamazaki, Hiroko; Fujinami, Kaoru; Tsunoda, Kazushige; Yamamoto, Shuichi

    2011-01-01

    Electrophysiological and morphological findings were studied in a case of acute zonal occult outer retinopathy (AZOOR) showing abnormal pattern visual evoked potentials (VEPs) at the onset and significant functional recovery in the natural course. A 21-year-old woman presented with acute onset of photopsia and a large scotoma in the right eye of 2 weeks duration. Her visual acuity was 20/20 in both eyes with no ophthalmoscopic and fluorescein angiographic abnormalities. However, a relative afferent pupillary defect and an enlarged blind spot were found in the right eye. The pattern VEPs were severely reduced when the right eye was stimulated. The amplitudes of both rod and cone full-field electroretinographics (ERGs) were reduced in the right eye. The amplitudes of the multifocal ERGs were reduced in the area of the enlarged blind spot. Irregularities in the inner segment/outer segment (IS/OS) line of the photoreceptors were observed over the nasal fovea by optical coherence tomography (OCT). The patient was followed without treatment. The enlarged blind spot disappeared in 3 months after the onset. At 5 months, reappearance of the IS/OS line was detected by OCT. At 6 months, the P(100) recovered to normal values. At 1 year, the reduced full-field ERGs were almost normal size and the multifocal ERGs in the area corresponding to the enlarged blind spot were also improved. ERG findings are crucial for differentiating AZOOR from retrobulbar neuritis, especially in patients with abnormal pattern VEPs. The pattern VEPs, full-field ERGs, multifocal ERGs, and OCT images can be abnormal in the early phase of AZOOR, but they can all improve during the natural course. PMID:21966193

  4. Searching for a major locus for male pattern baldness (MPB)

    SciTech Connect

    Anker, R.; Eisen, A.Z.; Donis-Keller, H. [Washington Univ. School of Medicine, St. Louis, MO (United States)

    1994-09-01

    Male pattern baldness (MPB) is a common trait in post-pubertal males. Approximately 50% of adult males present some degree of MPB by age 50. According to the classification provided by Hamilton in 1951 and modified by Norwood in 1975, the trait itself is a continuum that ranges from mild (Type I) to severe (Type VII) cases. In addition, there is extensive variability for the age of onset. The role of androgens in allowing the expression of this trait in males has been well established. This phenotype is uncommonly expressed in females. The high prevalence of the trait, the distribution of MPB as a continuous trait, and several non-allelic mutations identified in the mouse capable of affecting hair pattern, suggest that MPB is genetically heterogeneous. In order to reduce the probability of multiple non-allelic MPB genes within a pedigree, we selected 9 families in which MPB appears to segregate exclusively through the paternal lineage as compared to bilineal pedigrees. There are 32 males expressing this phenotype and females are treated as phenotype unknown. In general, affected individuals expressed the trait before 30 years of age with a severity of at least Type III or IV. We assumed an autosomal dominant model, with a gene frequency of 1/20 for the affected allele, and 90% penetrance. Simulation studies using the SLINK program with these pedigrees showed that these families would be sufficient to detect linkage under the assumption of a single major locus. If heterogeneity is present, the current resource does not have sufficient power to detect linkage at a statistically significant level, although candidate regions of the genome could be identified for further studies with additional pedigrees. Using 53 highly informative microsatellite markers, and a subset of 7 families, we have screened 30% of the genome. This search included several regions where candidate genes for MPB are located.

  5. Saccadic visual search training: a treatment for patients with homonymous hemianopia

    PubMed Central

    Pambakian, A; Mannan, S; Hodgson, T; Kennard, C

    2004-01-01

    Objectives: We describe a novel rehabilitation tool for patients with homonymous hemianopia based on a visual search (VS) paradigm that is portable, inexpensive, and easy to deploy. We hypothesised that by training patients to improve the efficiency of eye movements made in their blind field their disability would be alleviated. Methods: Twenty nine patients with homonymous visual field defects (HVFD) without neglect practised VS paradigms in 20 daily sessions over one month. Search fields comprising randomly positioned target and distracter elements, differing by a single feature, were displayed for three seconds on a dedicated television monitor in the patients' homes. Improvements were assessed by examining response time (RT), error rates in VS, perimetric visual fields (VFs) and visual search fields (VSFs), before and after treatment. Functional improvements were measured using objective visual tasks which represented activities of daily living (ADL) and a subjective questionnaire. Results: As a group the patients had significantly shorter mean RT in VS after training (p<0.001) and demonstrated a variety of mechanisms to account for this. Improvements were confined to the training period and maintained at follow up. Three patients had significantly longer RT after training. They had high initial error rates which improved with training. Patients performed ADL tasks significantly faster after training and reported significant subjective improvements. There was no concomitant enlargement of the VF, but there was a small but significant enlargement of the VSF. Conclusion: Patients can improve VS with practice. This usually involves shorter RTs, but occasionally a longer RT in a complex speed–accuracy trade-off. These changes translate to improved overall visual function, assessed objectively and subjectively, suggesting that they represent robust training effects. The underlying mechanism may involve the adoption of compensatory eye movement strategies. PMID:15377693

  6. The effect of flower-like and non-flower-like visual properties on choice of unrewarding patterns by bumblebees

    NASA Astrophysics Data System (ADS)

    Orbán, Levente L.; Plowright, Catherine M. S.

    2013-07-01

    How do distinct visual stimuli help bumblebees discover flowers before they have experienced any reward outside of their nest? Two visual floral properties, type of a pattern (concentric vs radial) and its position on unrewarding artificial flowers (central vs peripheral on corolla), were manipulated in two experiments. Both visual properties showed significant effects on floral choice. When pitted against each other, pattern was more important than position. Experiment 1 shows a significant effect of concentric pattern position, and experiment 2 shows a significant preference towards radial patterns regardless of their position. These results show that the presence of markings at the center of a flower are not so important as the presence of markings that will direct bees there.

  7. Structural connectivity patterns associated with the putative visual word form area and children's reading ability.

    PubMed

    Fan, Qiuyun; Anderson, Adam W; Davis, Nicole; Cutting, Laurie E

    2014-10-24

    With the advent of neuroimaging techniques, especially functional MRI (fMRI), studies have mapped brain regions that are associated with good and poor reading, most centrally a region within the left occipito-temporal/fusiform region (L-OT/F) often referred to as the visual word form area (VWFA). Despite an abundance of fMRI studies of the putative VWFA, research about its structural connectivity has just started. Provided that the putative VWFA may be connected to distributed regions in the brain, it remains unclear how this network is engaged in constituting a well-tuned reading circuitry in the brain. Here we used diffusion MRI to study the structural connectivity patterns of the putative VWFA and surrounding areas within the L-OT/F in children with typically developing (TD) reading ability and with word recognition deficits (WRD; sometimes referred to as dyslexia). We found that L-OT/F connectivity varied along a posterior-anterior gradient, with specific structural connectivity patterns related to reading ability in the ROIs centered upon the putative VWFA. Findings suggest that the architecture of the putative VWFA connectivity is fundamentally different between TD and WRD, with TD showing greater connectivity to linguistic regions than WRD, and WRD showing greater connectivity to visual and parahippocampal regions than TD. Findings thus reveal clear structural abnormalities underlying the functional abnormalities in the putative VWFA in WRD. PMID:25152466

  8. Effects of Individual Health Topic Familiarity on Activity Patterns During Health Information Searches

    PubMed Central

    Moriyama, Koichi; Fukui, Ken–ichi; Numao, Masayuki

    2015-01-01

    Background Non-medical professionals (consumers) are increasingly using the Internet to support their health information needs. However, the cognitive effort required to perform health information searches is affected by the consumer’s familiarity with health topics. Consumers may have different levels of familiarity with individual health topics. This variation in familiarity may cause misunderstandings because the information presented by search engines may not be understood correctly by the consumers. Objective As a first step toward the improvement of the health information search process, we aimed to examine the effects of health topic familiarity on health information search behaviors by identifying the common search activity patterns exhibited by groups of consumers with different levels of familiarity. Methods Each participant completed a health terminology familiarity questionnaire and health information search tasks. The responses to the familiarity questionnaire were used to grade the familiarity of participants with predefined health topics. The search task data were transcribed into a sequence of search activities using a coding scheme. A computational model was constructed from the sequence data using a Markov chain model to identify the common search patterns in each familiarity group. Results Forty participants were classified into L1 (not familiar), L2 (somewhat familiar), and L3 (familiar) groups based on their questionnaire responses. They had different levels of familiarity with four health topics. The video data obtained from all of the participants were transcribed into 4595 search activities (mean 28.7, SD 23.27 per session). The most frequent search activities and transitions in all the familiarity groups were related to evaluations of the relevancy of selected web pages in the retrieval results. However, the next most frequent transitions differed in each group and a chi-squared test confirmed this finding (P<.001). Next, according to the results of a perplexity evaluation, the health information search patterns were best represented as a 5-gram sequence pattern. The most common patterns in group L1 were frequent query modifications, with relatively low search efficiency, and accessing and evaluating selected results from a health website. Group L2 performed frequent query modifications, but with better search efficiency, and accessed and evaluated selected results from a health website. Finally, the members of group L3 successfully discovered relevant results from the first query submission, performed verification by accessing several health websites after they discovered relevant results, and directly accessed consumer health information websites. Conclusions Familiarity with health topics affects health information search behaviors. Our analysis of state transitions in search activities detected unique behaviors and common search activity patterns in each familiarity group during health information searches. PMID:25783222

  9. Adding a Visualization Feature to Web Search Engines: It’s Time

    SciTech Connect

    Wong, Pak C.

    2008-11-11

    Since the first world wide web (WWW) search engine quietly entered our lives in 1994, the “information need” behind web searching has rapidly grown into a multi-billion dollar business that dominates the internet landscape, drives e-commerce traffic, propels global economy, and affects the lives of the whole human race. Today’s search engines are faster, smarter, and more powerful than those released just a few years ago. With the vast investment pouring into research and development by leading web technology providers and the intense emotion behind corporate slogans such as “win the web” or “take back the web,” I can’t help but ask why are we still using the very same “text-only” interface that was used 13 years ago to browse our search engine results pages (SERPs)? Why has the SERP interface technology lagged so far behind in the web evolution when the corresponding search technology has advanced so rapidly? In this article I explore some current SERP interface issues, suggest a simple but practical visual-based interface design approach, and argue why a visual approach can be a strong candidate for tomorrow’s SERP interface.

  10. Query Suggestions for Mobile Search: Understanding Usage Patterns

    E-print Network

    Tomkins, Andrew

    Inc 1600 Amphitheatre Parkway, Mountain View, CA shumeet@google.com ABSTRACT Entering search terms that users who were asked to enter queries on a search interface with query suggestions rated their workload heavily on suggestions if they are provided. Users who were asked to enter queries on a search interface

  11. Explaining Eye Movements in the Visual Search of Varying Density Layouts Tim Halverson (thalvers@cs.uoregon.edu)

    E-print Network

    Hornof, Anthony

    Explaining Eye Movements in the Visual Search of Varying Density Layouts Tim Halverson (thalvers-justified, vertically-listed black words on a white background. The groups were arranged in three columns and two rows

  12. The Perceptual Interaction of Simple and Complex Point Symbol Shapes and Background Textures in Visual Search on Tourist Maps

    E-print Network

    Alhosani, Naeema M.

    2009-05-31

    This study investigated visual search for simple and complex geometric and pictorial point symbols displayed on light and dark smooth and textured map backgrounds. Group-administered tests asked subjects to count occurrences ...

  13. Serial, Covert, Shifts of Attention during Visual Search are Reflected by the Frontal Eye Fields and Correlated with Population Oscillations

    E-print Network

    Buschman, Timothy J.

    Attention regulates the flood of sensory information into a manageable stream, and so understanding how attention is controlled is central to understanding cognition. Competing theories suggest visual search involves serial ...

  14. Visual search in ecological and non-ecological displays: evidence for a non-monotonic effect of complexity on performance.

    PubMed

    Chassy, Philippe; Gobet, Fernand

    2013-01-01

    Considerable research has been carried out on visual search, with single or multiple targets. However, most studies have used artificial stimuli with low ecological validity. In addition, little is known about the effects of target complexity and expertise in visual search. Here, we investigate visual search in three conditions of complexity (detecting a king, detecting a check, and detecting a checkmate) with chess players of two levels of expertise (novices and club players). Results show that the influence of target complexity depends on level of structure of the visual display. Different functional relationships were found between artificial (random chess positions) and ecologically valid (game positions) stimuli: With artificial, but not with ecologically valid stimuli, a "pop out" effect was present when a target was visually more complex than distractors but could be captured by a memory chunk. This suggests that caution should be exercised when generalising from experiments using artificial stimuli with low ecological validity to real-life stimuli. PMID:23320084

  15. Searching, viewing, and visualizing data in the Biomolecular Interaction Network Database (BIND).

    PubMed

    Willis, Randall C; Hogue, Christopher W V

    2006-01-01

    The Biomolecular Interaction Network Database (BIND) comprises data from peer-reviewed literature and direct submissions. BIND's data model was the first of its kind to be peer-reviewed prior to database development, and is now a mature standard data format spanning molecular interactions, small molecule chemical reactions, and interfaces from three-dimensional structures, pathways, and genetic interaction networks. BIND supports additional file formats to achieve compatibility with other database efforts, including the HUPO PSI Level 2. BIND's latest software spans over 2000 metadata fields and is constructed using the Java Enterprise Systems software platform. Protocols are provided for searching BIND via the Internet, as well as for viewing and exporting search results or individual records. Furthermore, a protocol is provided for visualizing biomolecular interactions within BIND or for transferring this information to the visualization tools Cytoscape and Cn3D. PMID:18428770

  16. Progression of Patterns (POP): A Machine Classifier Algorithm to Identify Glaucoma Progression in Visual Fields

    PubMed Central

    Goldbaum, Michael H.; Lee, Intae; Jang, Giljin; Balasubramanian, Madhusudhanan; Sample, Pamela A.; Weinreb, Robert N.; Liebmann, Jeffrey M.; Girkin, Christopher A.; Anderson, Douglas R.; Zangwill, Linda M.; Fredette, Marie-Josee; Jung, Tzyy-Ping; Medeiros, Felipe A.; Bowd, Christopher

    2012-01-01

    Purpose. We evaluated Progression of Patterns (POP) for its ability to identify progression of glaucomatous visual field (VF) defects. Methods. POP uses variational Bayesian independent component mixture model (VIM), a machine learning classifier (MLC) developed previously. VIM separated Swedish Interactive Thresholding Algorithm (SITA) VFs from a set of 2,085 normal and glaucomatous eyes into nine axes (VF patterns): seven glaucomatous. Stable glaucoma was simulated in a second set of 55 patient eyes with five VFs each, collected within four weeks. A third set of 628 eyes with 4,186 VFs (mean ± SD of 6.7 ± 1.7 VFs over 4.0 ± 1.4 years) was tested for progression. Tested eyes were placed into suspect and glaucoma categories at baseline, based on VFs and disk stereoscopic photographs; a subset of eyes had stereophotographic evidence of progressive glaucomatous optic neuropathy (PGON). Each sequence of fields was projected along seven VIM glaucoma axes. Linear regression (LR) slopes generated from projections onto each axis yielded a degree of confidence (DOC) that there was progression. At 95% specificity, progression cutoffs were established for POP, visual field index (VFI), and mean deviation (MD). Guided progression analysis (GPA) was also compared. Results. POP identified a statistically similar number of eyes (P > 0.05) as progressing compared with VFI, MD, and GPA in suspects (3.8%, 2.7%, 5.6%, and 2.9%, respectively), and more eyes than GPA (P = 0.01) in glaucoma (16.0%, 15.3%, 12.0%, and 7.3%, respectively), and more eyes than GPA (P = 0.05) in PGON eyes (26.3%, 23.7%, 27.6%, and 14.5%, respectively). Conclusions. POP, with its display of DOC of progression and its identification of progressing VF defect pattern, adds to the information available to the clinician for detecting VF progression. PMID:22786913

  17. The Visual Hemifield Asymmetry in the Spatial Blink during Singleton Search and Feature Search

    ERIC Educational Resources Information Center

    Burnham, Bryan R.; Rozell, Cassandra A.; Kasper, Alex; Bianco, Nicole E.; Delliturri, Antony

    2011-01-01

    The present study examined a visual field asymmetry in the contingent capture of attention that was previously observed by Du and Abrams (2010). In our first experiment, color singleton distractors that matched the color of a to-be-detected target produced a stronger capture of attention when they appeared in the left visual hemifield than in the…

  18. Color singleton pop-out does not always poop out: An alternative to visual search

    Microsoft Academic Search

    William Prinzmetal; Nadia Taylor

    2006-01-01

    Folk psychology suggests that when an observer views a scene, a unique item will stand out and draw attention to itself. This\\u000a belief stands in contrast to numerous studies in visual search that have found that a unique target item (e.g., a unique color)\\u000a is not identified more quickly than a nonunique target. We hypothesized that this finding is the

  19. A Model of Object-Based Attention That Guides Active Visual Search to Behaviourally Relevant Locations

    Microsoft Academic Search

    Linda J. Lanyon; Susan L. Denham

    2004-01-01

    \\u000a During active visual search for a colour-orientation conjunction target, scan paths tend to be guided to target coloured locations\\u000a (Motter & Belky, 1998). An active vision model, using biased competition, is able to replicate this behaviour. At the cellular\\u000a level, the model replicates spatial and object-based attentional effects over time courses observed in single cell recordings\\u000a in monkeys (Chelazzi et

  20. VSearch Color: Full-color visual search experiments on the Macintosh II

    Microsoft Academic Search

    James T. Enns; Ronald A. Rensink

    1991-01-01

    We describe an update to our visual search software for the Macintosh line of computers. The new software, VSearch Color,\\u000a gives users access to the full-color capabilites of the Macintosh II line. One of the key features of the new software is\\u000a its ability to treat graphics information separately from color information. This makes it easy to study color independently

  1. Improvement in Visual Search with Practice: Mapping Learning-Related Changes in Neurocognitive Stages of Processing

    PubMed Central

    Clark, Kait; Appelbaum, L. Gregory; van den Berg, Berry; Mitroff, Stephen R.

    2015-01-01

    Practice can improve performance on visual search tasks; the neural mechanisms underlying such improvements, however, are not clear. Response time typically shortens with practice, but which components of the stimulus–response processing chain facilitate this behavioral change? Improved search performance could result from enhancements in various cognitive processing stages, including (1) sensory processing, (2) attentional allocation, (3) target discrimination, (4) motor-response preparation, and/or (5) response execution. We measured event-related potentials (ERPs) as human participants completed a five-day visual-search protocol in which they reported the orientation of a color popout target within an array of ellipses. We assessed changes in behavioral performance and in ERP components associated with various stages of processing. After practice, response time decreased in all participants (while accuracy remained consistent), and electrophysiological measures revealed modulation of several ERP components. First, amplitudes of the early sensory-evoked N1 component at 150 ms increased bilaterally, indicating enhanced visual sensory processing of the array. Second, the negative-polarity posterior–contralateral component (N2pc, 170–250 ms) was earlier and larger, demonstrating enhanced attentional orienting. Third, the amplitude of the sustained posterior contralateral negativity component (SPCN, 300–400 ms) decreased, indicating facilitated target discrimination. Finally, faster motor-response preparation and execution were observed after practice, as indicated by latency changes in both the stimulus-locked and response-locked lateralized readiness potentials (LRPs). These electrophysiological results delineate the functional plasticity in key mechanisms underlying visual search with high temporal resolution and illustrate how practice influences various cognitive and neural processing stages leading to enhanced behavioral performance. PMID:25834059

  2. A distributed architecture for searching, retrieving and visualizing complex 3D models on Personal Digital Assistants

    Microsoft Academic Search

    Andrea Sanna; Claudio Zunino; Fabrizio Lamberti

    2004-01-01

    Mobile devices are significantly changing the human–computer interaction. In particular, the ubiquitous access to remote resources is one of the most interesting characteristics achievable by using mobile devices such as Personal Digital Assistants, cellular phones and tablets.This paper presents an architecture that allows users to search and visualize complex 3D models over Personal Digital Assistants. A peer-to-peer network of brokers

  3. Invisible displacement understanding in domestic dogs ( Canis familiaris ): the role of visual cues in search behavior

    Microsoft Academic Search

    Sylvain Fiset; Valérie LeBlanc

    2007-01-01

    Recently, (Collier-Baker E, Davis JM, Suddendorf T (2004) J Comp Psychol 118:421–433) suggested that domestic dogs do not\\u000a understand invisible displacements. In the present study, we further investigated the hypothesis that the search behavior\\u000a of domestic dogs in invisible displacements is guided by various visual cues inherent to the task rather than by mental representation\\u000a of an object’s past trajectory.

  4. Expectation violations in sensorimotor sequences: shifting from LTM-based attentional selection to visual search.

    PubMed

    Foerster, Rebecca M; Schneider, Werner X

    2015-03-01

    Long-term memory (LTM) delivers important control signals for attentional selection. LTM expectations have an important role in guiding the task-driven sequence of covert attention and gaze shifts, especially in well-practiced multistep sensorimotor actions. What happens when LTM expectations are disconfirmed? Does a sensory-based visual-search mode of attentional selection replace the LTM-based mode? What happens when prior LTM expectations become valid again? We investigated these questions in a computerized version of the number-connection test. Participants clicked on spatially distributed numbered shapes in ascending order while gaze was recorded. Sixty trials were performed with a constant spatial arrangement. In 20 consecutive trials, either numbers, shapes, both, or no features switched position. In 20 reversion trials, participants worked on the original arrangement. Only the sequence-affecting number switches elicited slower clicking, visual search-like scanning, and lower eye-hand synchrony. The effects were neither limited to the exchanged numbers nor to the corresponding actions. Thus, expectation violations in a well-learned sensorimotor sequence cause a regression from LTM-based attentional selection to visual search beyond deviant-related actions and locations. Effects lasted for several trials and reappeared during reversion. PMID:25708482

  5. Developmental changes in the flotillin-1 expression pattern of the rat visual cortex.

    PubMed

    Nakadate, K

    2015-04-30

    Ocular dominance plasticity is activity dependent, changes in response to eye competition, and is transitory during developmental stages. Lipid rafts have modulatory functions in cellular, physiological, and behavioral processes. Although many of these modulatory roles are mediated by flotillin-1, a lipid raft-associated protein, the ontogenetic changes in the cellular and subcellular distribution patterns of flotillin-1 are unclear. I investigated the developmental pattern of the distribution of flotillin-1 in the rat visual cortex with immunohistochemistry at both light and electron microscopic levels. An affinity-purified anti-flotillin-1 antibody reacted with a single band of about 40-50kDa in total proteins prepared from the rat visual cortex. Flotillin-1 levels transiently increased on postnatal days 21-35. Flotillin-1 immunoreactivity at 3weeks of age was broadly distributed though all visual cortical layers, but it exhibited a relatively higher density in layers II/III and V/VI. Flotillin-1 immunoreactivity at 3months of age was significantly decreased compared with that at 3weeks of age. Strong flotillin-1 immunoreactivity was observed in both neuronal perikarya and processes at 3weeks of age. Double-labeling experiments with anti-microtubule-associated protein 2, anti-neurofilament, anti-synaptophysin, anti-vesicular glutamate transporter 1, anti-vesicular glutamate transporter 2, anti-glial fibrillary acidic protein, and flotillin-1 mainly labeled the somata of excitatory neurons and corticocortical synapses. Some flotillin-1 was distributed in excitatory neuron axons, thalamocortical synapses, astrocytes, oligodendrocytes, and microglial cells. Immunoelectron microscopy revealed numerous regions of flotillin-1 immunoreactivity near the rough endoplasmic reticulum in neurons and presynaptic regions at 3weeks of age. These findings illustrate early developmental changes in the cellular and subcellular localization of flotillin-1 protein in the rat visual cortex. Moreover, the ultrastructural distribution of flotillin-1 immunoreactivity suggested that flotillin-1 was transported mainly into presynaptic terminals where it exerts effects at the presynaptic sites of excitatory and inhibitory neurons. PMID:25732136

  6. Modeling the Effect of Selection History on Pop-Out Visual Search

    PubMed Central

    Tseng, Yuan-Chi; Glaser, Joshua I.; Caddigan, Eamon; Lleras, Alejandro

    2014-01-01

    While attentional effects in visual selection tasks have traditionally been assigned “top-down” or “bottom-up” origins, more recently it has been proposed that there are three major factors affecting visual selection: (1) physical salience, (2) current goals and (3) selection history. Here, we look further into selection history by investigating Priming of Pop-out (POP) and the Distractor Preview Effect (DPE), two inter-trial effects that demonstrate the influence of recent history on visual search performance. Using the Ratcliff diffusion model, we model observed saccadic selections from an oddball search experiment that included a mix of both POP and DPE conditions. We find that the Ratcliff diffusion model can effectively model the manner in which selection history affects current attentional control in visual inter-trial effects. The model evidence shows that bias regarding the current trial's most likely target color is the most critical parameter underlying the effect of selection history. Our results are consistent with the view that the 3-item color-oddball task used for POP and DPE experiments is best understood as an attentional decision making task. PMID:24595032

  7. Modeling the effect of selection history on pop-out visual search.

    PubMed

    Tseng, Yuan-Chi; Glaser, Joshua I; Caddigan, Eamon; Lleras, Alejandro

    2014-01-01

    While attentional effects in visual selection tasks have traditionally been assigned "top-down" or "bottom-up" origins, more recently it has been proposed that there are three major factors affecting visual selection: (1) physical salience, (2) current goals and (3) selection history. Here, we look further into selection history by investigating Priming of Pop-out (POP) and the Distractor Preview Effect (DPE), two inter-trial effects that demonstrate the influence of recent history on visual search performance. Using the Ratcliff diffusion model, we model observed saccadic selections from an oddball search experiment that included a mix of both POP and DPE conditions. We find that the Ratcliff diffusion model can effectively model the manner in which selection history affects current attentional control in visual inter-trial effects. The model evidence shows that bias regarding the current trial's most likely target color is the most critical parameter underlying the effect of selection history. Our results are consistent with the view that the 3-item color-oddball task used for POP and DPE experiments is best understood as an attentional decision making task. PMID:24595032

  8. You can detect the trees as well as the forest when adding the leaves: Evidence from visual search tasks containing three-level hierarchical stimuli.

    PubMed

    Krakowski, Claire-Sara; Borst, Grégoire; Pineau, Arlette; Houdé, Olivier; Poirel, Nicolas

    2015-05-01

    The present study investigated how multiple levels of hierarchical stimuli (i.e., global, intermediate and local) are processed during a visual search task. Healthy adults participated in a visual search task in which a target was either present or not at one of the three levels of hierarchical stimuli (global geometrical form made by intermediate forms themselves constituted by local forms). By varying the number of distractors, the results showed that targets presented at global and intermediate levels were detected efficiently (i.e., the detection times did not vary with the number of distractors) whereas local targets were processed less efficiently (i.e., the detection times increased with the number of distractors). Additional experiments confirmed that these results were not due to the size of the target elements or to the spatial proximity among the structural levels. Taken together, these results show that the most local level is always processed less efficiently, suggesting that it is disadvantaged during the competition for attentional resources compared to higher structural levels. The present study thus supports the view that the processing occurring in visual search acts dichotomously rather than continuously. Given that pure structuralist and pure space-based models of attention cannot account for the pattern of our findings, we discuss the implication for perception, attentional selection and executive control of target position on hierarchical stimuli. PMID:25796055

  9. Visualization of Spatial Knowledge with Ontology Trees and Adaptable Search Result Grids in the Era of Web 3.0

    Microsoft Academic Search

    Matthias Loskyll; Dominikus Heckmann; Christian Glahn

    2007-01-01

    With the emerging trend of Web 3.0 and the resulting huge amount of user- generated semantically-enriched data, improved ways of knowledge visualization and human computer interaction are needed. We present several techniques of visualizing particularly spatial knowledge in largely scalable, clear structured ontology trees on the web. In addition, we describe the representation of search results with a combined approach

  10. GOAL DIRECTED VISUAL SEARCH BASED ON COLOR CUES: CO-OPERATIVE EFFECTS OF TOP-DOWN & BOTTOM-UP

    E-print Network

    Canosa, Roxanne

    of the top-down (cognitive cue) and bottom-up (low-level feature conspicuity) processes. Often during visual (1985), where a saliency map reflects the relative saliency of objects from their surrounding. A top-down1 GOAL DIRECTED VISUAL SEARCH BASED ON COLOR CUES: CO-OPERATIVE EFFECTS OF TOP-DOWN & BOTTOM

  11. The Development of Visual Search in Infants and Very Young Children.

    ERIC Educational Resources Information Center

    Gerhardstein, Peter; Rovee-Collier, Carolyn

    2002-01-01

    Trained 1- to 3-year-olds to touch a video screen displaying a unique target and appearing among varying numbers of distracters; correct responses triggered a sound and four animated objects on the screen. Found that children's reaction time patterns resembled those from adults in corresponding search tasks, suggesting that basic perceptual…

  12. Visual Search and Attention in Blue Jays (Cyanocitta cristata): Associative Cuing and Sequential Priming

    PubMed Central

    Goto, Kazuhiro; Bond, Alan B.; Burks, Marianna; Kamil, Alan C.

    2014-01-01

    Visual search for complex natural targets requires focal attention, either cued by predictive stimulus associations or primed by a representation of the most recently detected target. Since both processes can focus visual attention, cuing and priming were compared in an operant search task to evaluate their relative impacts on performance and to determine the nature of their interaction in combined treatments. Blue jays were trained to search for pairs of alternative targets among distractors. Informative or ambiguous color cues were provided prior to each trial, and targets were presented either in homogeneous blocked sequences or in constrained random order. Initial task acquisition was facilitated by priming in general, but was significantly retarded when targets were both cued and primed, indicating that the two processes interfered with each other during training. At asymptote, attentional effects were manifested mainly in inhibition, increasing latency in miscued trials and decreasing accuracy on primed trials following an unexpected target switch. A combination of cuing and priming was found to interfere with performance in such unexpected trials, apparently a result of the limited capacity of working memory. Because the ecological factors that promote priming and cuing are rather disparate, it is not clear whether they ever jointly and simultaneously contribute to natural predatory search. PMID:24893217

  13. Visual search and attention in blue jays (Cyanocitta cristata): Associative cuing and sequential priming.

    PubMed

    Goto, Kazuhiro; Bond, Alan B; Burks, Marianna; Kamil, Alan C

    2014-04-01

    Visual search for complex natural targets requires focal attention, either cued by predictive stimulus associations or primed by a representation of the most recently detected target. Because both processes can focus visual attention, cuing and priming were compared in an operant search task to evaluate their relative impacts on performance and to determine the nature of their interaction in combined treatments. Blue jays were trained to search for pairs of alternative targets among distractors. Informative or ambiguous color cues were provided before each trial, and targets were presented either in homogeneous blocked sequences or in constrained random order. Initial task acquisition was facilitated by priming in general, but was significantly retarded when targets were both cued and primed, indicating that the two processes interfered with each other during training. At asymptote, attentional effects were manifested mainly in inhibition, increasing latency in miscued trials and decreasing accuracy on primed trials following an unexpected target switch. A combination of cuing and priming was found to interfere with performance in such unexpected trials, apparently a result of the limited capacity of working memory. Because the ecological factors that promote priming or cuing are rather disparate, it is not clear whether they ever simultaneously contribute to natural predatory search. PMID:24893217

  14. Modeling visual search using three-parameter probability functions in a hierarchical Bayesian framework.

    PubMed

    Lin, Yi-Shin; Heinke, Dietmar; Humphreys, Glyn W

    2015-04-01

    In this study, we applied Bayesian-based distributional analyses to examine the shapes of response time (RT) distributions in three visual search paradigms, which varied in task difficulty. In further analyses we investigated two common observations in visual search-the effects of display size and of variations in search efficiency across different task conditions-following a design that had been used in previous studies (Palmer, Horowitz, Torralba, & Wolfe, Journal of Experimental Psychology: Human Perception and Performance, 37, 58-71, 2011; Wolfe, Palmer, & Horowitz, Vision Research, 50, 1304-1311, 2010) in which parameters of the response distributions were measured. Our study showed that the distributional parameters in an experimental condition can be reliably estimated by moderate sample sizes when Monte Carlo simulation techniques are applied. More importantly, by analyzing trial RTs, we were able to extract paradigm-dependent shape changes in the RT distributions that could be accounted for by using the EZ2 diffusion model. The study showed that Bayesian-based RT distribution analyses can provide an important means to investigate the underlying cognitive processes in search, including stimulus grouping and the bottom-up guidance of attention. PMID:25678272

  15. A probabilistic model for analysing the effect of performance levels on visual behaviour patterns of young sailors in simulated navigation.

    PubMed

    Manzanares, Aarón; Menayo, Ruperto; Segado, Francisco; Salmerón, Diego; Cano, Juan Antonio

    2015-04-01

    The visual behaviour is a determining factor in sailing due to the influence of the environmental conditions. The aim of this research was to determine the visual behaviour pattern in sailors with different practice time in one star race, applying a probabilistic model based on Markov chains. The sample of this study consisted of 20 sailors, distributed in two groups, top ranking (n = 10) and bottom ranking (n = 10), all of them competed in the Optimist Class. An automated system of measurement, which integrates the VSail-Trainer® sail simulator and the Eye Tracking System(TM) was used. The variables under consideration were the sequence of fixations and the fixation recurrence time performed on each location by the sailors. The event consisted of one of simulated regatta start, with stable conditions of wind, competitor and sea. Results show that top ranking sailors perform a low recurrence time on relevant locations and higher on irrelevant locations while bottom ranking sailors make a low recurrence time in most of the locations. The visual pattern performed by bottom ranking sailors is focused around two visual pivots, which does not happen in the top ranking sailor's pattern. In conclusion, the Markov chains analysis has allowed knowing the visual behaviour pattern of the top and bottom ranking sailors and its comparison. PMID:25296294

  16. White matter hyperintensities are associated with visual search behavior independent of generalized slowing in aging

    PubMed Central

    Lockhart, Samuel N.; Roach, Alexandra E.; Luck, Steven J.; Geng, Joy; Beckett, Laurel; Carmichael, Owen; DeCarli, Charles

    2014-01-01

    A fundamental controversy is whether cognitive decline with advancing age can be entirely explained by decreased processing speed, or whether specific neural changes can elicit cognitive decline, independent of slowing. These hypotheses are anchored by studies of healthy older individuals where age is presumed the sole influence. Unfortunately, advancing age is also associated with asymptomatic brain white matter injury. We hypothesized that differences in white matter injury extent, manifest by MRI white matter hyperintensities (WMH), mediate differences in visual attentional control in healthy aging, beyond processing speed differences. We tested young and cognitively healthy older adults on search tasks indexing speed and attentional control. Increasing age was associated with generally slowed performance. WMH was also associated with slowed search times independent of processing speed differences. Consistent with evidence attributing reduced network connectivity to WMH, these results conclusively demonstrate that clinically silent white matter injury contributes to slower search performance indicative of compromised cognitive control, independent of generalized slowing of processing speed. PMID:24183716

  17. Gaze and visual search strategies of children with Asperger syndrome/high functioning autism viewing a magic trick.

    PubMed

    Joosten, Annette; Girdler, Sonya; Albrecht, Matthew A; Horlin, Chiara; Falkmer, Marita; Leung, Denise; Ordqvist, Anna; Fleischer, Håkan; Falkmer, Torbjörn

    2014-05-27

    Abstract Objective: To examine visual search patterns and strategies used by children with and without Asperger syndrome/high functioning autism (AS/HFA) while watching a magic trick. Limited responsivity to gaze cues is hypothesised to contribute to social deficits in children with AS/HFA. Methods: Twenty-one children with AS/HFA and 31 matched peers viewed a video of a gaze-cued magic trick twice. Between the viewings, they were informed about how the trick was performed. Participants' eye movements were recorded using a head-mounted eye-tracker. Results: Children with AS/HFA looked less frequently and had shorter fixation on the magician's direct and averted gazes during both viewings and more frequently at not gaze-cued objects and on areas outside the magician's face. After being informed of how the trick was conducted, both groups made fewer fixations on gaze-cued objects and direct gaze. Conclusions: Information may enhance effective visual strategies in children with and without AS/HFA. PMID:24866104

  18. Moiré patterns of two different elongated circular gratings for the fine visual measurement of linear displacements

    NASA Astrophysics Data System (ADS)

    Song, Jong Sup; Lee, Young Ho; Jo, Jae Heung; Chang, Soo; Yuk, Keun Cheol

    1998-08-01

    An elongated circular grating having the shape of an athletic track was proposed to determine both the moving displacement and its direction within an accuracy of ten times that of conventional circular gratings. The properties of moiré fringes from two complementary elongated circular gratings were investigated for fine visual measurement of linear displacements. Moiré patterns formed by superposition of two different elongated circular gratings were demonstrated to provide a simple fringe-counting method for determining both the relative linear displacement and its direction within the accuracy of 1/10 pitch of the grating. The measurement of the refractive indices of C 6H 12 and CCl 4 and the thermal expansion coefficient of aluminium, using elongated circular gratings, are presented.

  19. Increasing robustness against background noise: visual pattern recognition by a neocognitron.

    PubMed

    Fukushima, Kunihiko

    2011-09-01

    The neocognitron is a hierarchical multi-layered neural network capable of robust visual pattern recognition. It has been demonstrated that recent versions of the neocognitron exhibit excellent performance for recognizing handwritten digits. When characters are written on a noisy background, however, recognition rate was not always satisfactory. To find out the causes of vulnerability to noise, this paper analyzes the behavior of feature-extracting S-cells. It then proposes the use of subtractive inhibition to S-cells from V-cells, which calculate the average of input signals to the S-cells with a root-mean-square. Together with this, several modifications have also been applied to the neocognitron. Computer simulation shows that the new neocognitron is much more robust against background noise than the conventional ones. PMID:21482455

  20. Preliminary observations on the ability of hyperspectral imaging to provide detection and visualization of bloodstain patterns on black fabrics.

    PubMed

    Schuler, Rebecca L; Kish, Paul E; Plese, Cara A

    2012-11-01

    The analysis of bloodstain patterns can assist investigators in understanding the circumstances surrounding a violent crime. Bloodstains are routinely subjected to pattern analysis, which is inherently dependent upon the ability of the examiner to locate and visualize bloodstain patterns on items of evidence. Often, the ability to properly visualize bloodstain patterns is challenging, especially when the stain patterns occur on dark and/or patterned substrates. In this study, preliminary research was performed to better understand how near-infrared reflectance hyperspectral imaging (HSI) could be used to observe bloodstain patterns on commonly encountered black fabrics. The ability of HSI to visualize latent bloodstains on several commonly encountered substrates is demonstrated. The images acquired through HSI are of sufficient quality to allow for differentiation between stains produced from an impact mechanism or a transfer mechanism. This study also serves as a proof of concept in the differentiation of multiple staining materials. Because of its ability to generate spectral data, the data provide a preliminary separation of stains where more than one type of stain existed. PMID:22563710

  1. Visual Signals Vertically Extend the Perceptual Span in Searching a Text: A Gaze-Contingent Window Study

    ERIC Educational Resources Information Center

    Cauchard, Fabrice; Eyrolle, Helene; Cellier, Jean-Marie; Hyona, Jukka

    2010-01-01

    This study investigated the effect of visual signals on perceptual span in text search and the kinds of signal information that facilitate the search. Participants were asked to find answers to specific questions in chapter-length texts in either a normal or a window condition, where the text disappeared beyond a vertical 3 degrees gaze-contingent…

  2. Errors in low prevalence visual search: Easy to produce,hard to cure Brigham and Women's Hospital

    E-print Network

    Errors in low prevalence visual search: Easy to produce,hard to cure Brigham and Women's Hospital 1 V E R I TAS Harvard Medical School2 1 1,2 1 1,2 Michael J.Van Wert, Todd S.Horowitz, Skyler S 1 Experiment 2 Many socially important search tasks (e.g.,medical screening and airport security

  3. Intracellular Trafficking in Drosophila Visual System Development: A Basis for Pattern Formation Through Simple Mechanisms

    PubMed Central

    Chan, Chih-Chiang; Epstein, Daniel; Hiesinger, P. Robin

    2012-01-01

    Intracellular trafficking underlies cellular functions ranging from membrane remodeling to receptor activation. During multicellular organ development, these basic cell biological functions are required as both passive machinery and active signaling regulators. Exocytosis, endocytosis, and recycling of several key signaling receptors have long been known to actively regulate morphogenesis and pattern formation during Drosophila eye development. Hence, intracellular membrane trafficking not only sets the cell biological stage for receptor-mediated signaling but also actively controls signaling through spatiotemporally regulated receptor localization. In contrast to eye development, the role of intracellular trafficking for the establishment of the eye-to-brain connectivity map has only recently received more attention. It is still poorly understood how guidance receptors are spatiotemporally regulated to serve as meaningful synapse formation signals. Yet, the Drosophila visual system provides some of the most striking examples for the regulatory role of intracellular trafficking during multicellular organ development. In this review we will first highlight the experimental and conceptual advances that motivate the study of intracellular trafficking during Drosophila visual system development. We will then illuminate the development of the eye, the eye-to-brain connectivity map and the optic lobe from the perspective of cell biological dynamics. Finally, we provide a conceptual framework that seeks to explain how the interplay of simple genetically encoded intracellular trafficking events governs the seemingly complex cellular behaviors, which in turn determine the developmental product. PMID:21714102

  4. Discovering anatomical patterns with pathological meaning by clustering of visual primitives in structural brain MRI

    NASA Astrophysics Data System (ADS)

    Leon, Juan; Pulido, Andrea; Romero, Eduardo

    2015-01-01

    Computational anatomy is a subdiscipline of the anatomy that studies macroscopic details of the human body structure using a set of automatic techniques. Different reference systems have been developed for brain mapping and morphometry in functional and structural studies. Several models integrate particular anatomical regions to highlight pathological patterns in structural brain MRI, a really challenging task due to the complexity, variability, and nonlinearity of the human brain anatomy. In this paper, we present a strategy that aims to find anatomical regions with pathological meaning by using a probabilistic analysis. Our method starts by extracting visual primitives from brain MRI that are partitioned into small patches and which are then softly clustered, forming different regions not necessarily connected. Each of these regions is described by a co- occurrence histogram of visual features, upon which a probabilistic semantic analysis is used to find the underlying structure of the information, i.e., separated regions by their low level similarity. The proposed approach was tested with the OASIS data set which includes 69 Alzheimer's disease (AD) patients and 65 healthy subjects (NC).

  5. A comparison of fMRI adaptation and multivariate pattern classification analysis in visual cortex

    PubMed Central

    Sapountzis, Panagiotis; Schluppeck, Denis; Bowtell, Richard; Peirce, Jonathan W.

    2010-01-01

    Functional magnetic resonance imaging (fMRI) has become a ubiquitous tool in cognitive neuroscience. The technique allows noninvasive measurements of cortical responses in the human brain, but only on the millimeter scale. Because a typical voxel contains many thousands of neurons with varied properties, establishing the selectivity of their responses directly is impossible. In recent years, two methods using fMRI aimed at studying the selectivity of neuronal populations on a ‘subvoxel’ scale have been heavily used. The first technique, fMRI adaptation, relies on the observation that the blood oxygen level-dependent (BOLD) response in a given voxel is reduced after prolonged presentation of a stimulus, and that this reduction is selective to the characteristics of the repeated stimuli (adapters). The second technique, multivariate pattern analysis (MVPA), makes use of multivariate statistics to recover small biases in individual voxels in their responses to different stimuli. It is thought that these biases arise due to the uneven distribution of neurons (with different properties) sampled by the many voxels in the imaged volume. These two techniques have not been compared explicitly, however, and little is known about their relative sensitivities. Here, we compared fMRI results from orientation-specific visual adaptation and orientation–classification by MVPA, using optimized experimental designs for each, and found that the multivariate pattern classification approach was more sensitive to small differences in stimulus orientation than the adaptation paradigm. Estimates of orientation selectivity obtained with the two methods were, however, very highly correlated across visual areas. PMID:19815081

  6. Visual-textual joint relevance learning for tag-based social image search.

    PubMed

    Gao, Yue; Wang, Meng; Zha, Zheng-Jun; Shen, Jialie; Li, Xuelong; Wu, Xindong

    2013-01-01

    Due to the popularity of social media websites, extensive research efforts have been dedicated to tag-based social image search. Both visual information and tags have been investigated in the research field. However, most existing methods use tags and visual characteristics either separately or sequentially in order to estimate the relevance of images. In this paper, we propose an approach that simultaneously utilizes both visual and textual information to estimate the relevance of user tagged images. The relevance estimation is determined with a hypergraph learning approach. In this method, a social image hypergraph is constructed, where vertices represent images and hyperedges represent visual or textual terms. Learning is achieved with use of a set of pseudo-positive images, where the weights of hyperedges are updated throughout the learning process. In this way, the impact of different tags and visual words can be automatically modulated. Comparative results of the experiments conducted on a dataset including 370+images are presented, which demonstrate the effectiveness of the proposed approach. PMID:22692911

  7. Latent class modeling of website users’ search patterns: Implications for online market segmentation

    Microsoft Academic Search

    José G. Dias; Jeroen K. Vermunt

    2007-01-01

    Appropriate modeling of web use patterns may yield very relevant marketing and retailing information. We propose using a model-based clustering approach for market segmentation based on website users’ search patterns. We not only provide a detailed discussion of technical issues such as the problem of the selection of the number of segments, but also a very interesting empirical illustration of

  8. Accuracy of Using Visual Identification of White Sharks to Estimate Residency Patterns

    PubMed Central

    Delaney, David G.; Johnson, Ryan; Bester, Marthán N.; Gennari, Enrico

    2012-01-01

    Determining the residency of an aquatic species is important but challenging and it remains unclear what is the best sampling methodology. Photo-identification has been used extensively to estimate patterns of animals' residency and is arguably the most common approach, but it may not be the most effective approach in marine environments. To examine this, in 2005, we deployed acoustic transmitters on 22 white sharks (Carcharodon carcharias) in Mossel Bay, South Africa to quantify the probability of detecting these tagged sharks by photo-identification and different deployment strategies of acoustic telemetry equipment. Using the data collected by the different sampling approaches (detections from an acoustic listening station deployed under a chumming vessel versus those from visual sightings and photo-identification), we quantified the methodologies' probability of detection and determined if the sampling approaches, also including an acoustic telemetry array, produce comparable results for patterns of residency. Photo-identification had the lowest probability of detection and underestimated residency. The underestimation is driven by various factors primarily that acoustic telemetry monitors a large area and this reduces the occurrence of false negatives. Therefore, we propose that researchers need to use acoustic telemetry and also continue to develop new sampling approaches as photo-identification techniques are inadequate to determine residency. Using the methods presented in this paper will allow researchers to further refine sampling approaches that enable them to collect more accurate data that will result in better research and more informed management efforts and policy decisions. PMID:22514662

  9. Low-level image properties of visual objects predict patterns of neural response across category-selective regions of the ventral visual pathway.

    PubMed

    Rice, Grace E; Watson, David M; Hartley, Tom; Andrews, Timothy J

    2014-06-25

    Neuroimaging studies have revealed strong selectivity for object categories in high-level regions of the human visual system. However, it is unknown whether this selectivity is truly based on object category, or whether it reflects tuning for low-level features that are common to images from a particular category. To address this issue, we measured the neural response to different object categories across the ventral visual pathway. Each object category elicited a distinct neural pattern of response. Next, we compared the patterns of neural response between object categories. We found a strong positive correlation between the neural patterns and the underlying low-level image properties. Importantly, this correlation was still evident when the within-category correlations were removed from the analysis. Next, we asked whether basic image properties could also explain variation in the pattern of response to different exemplars from one object category (faces). A significant correlation was also evident between the similarity of neural patterns of response and the low-level properties of different faces, particularly in regions associated with face processing. These results suggest that the appearance of category-selective regions at this coarse scale of representation may be explained by the systematic convergence of responses to low-level features that are characteristic of each category. PMID:24966383

  10. Spatiotemporal changes in neural response patterns to faces varying in visual familiarity.

    PubMed

    Natu, Vaidehi S; O'Toole, Alice J

    2015-03-01

    Increasing experience with a previously unfamiliar face improves human ability to recognize it in challenging and novel viewing conditions. Differential neural responses to familiar versus unfamiliar faces in multiple regions of the ventral-temporal and parietal cortex have been reported in previous work, but with limited attention to how behavioral and neural measures change with increasing familiarity. We examined changes in the spatial and temporal characteristics of neural response patterns elicited by faces that vary in their degree of visual familiarity. First, we developed a behavioral paradigm to familiarize participants to low-, medium-, and high-levels of familiarity with faces. Recognition of novel, naturalistic images of the learned individuals improved with increasing familiarity with faces. Next, a new set of participants learned faces using the behavioral paradigm, outside the fMRI scanner, and subsequently viewed blocks of whole-body images of the learned and novel people, inside the scanner. We found that the face-selective FFA and OFA, and a combination of the ventral-temporal areas (e.g., fusiform gyrus) and parietal areas (e.g., precuneus) contained patterns useful for classifying highly familiar versus unfamiliar faces. Classification along the temporal-sequence of the face blocks revealed an early separation of neural patterns elicited in response to highly familiar versus unfamiliar faces in the FFA and OFA, but not in other regions of interest. This indicates the potential for a rapid assessment of the "known versus unknown" status of faces in core face-selective regions of the brain. The present study provides a first look at the perceptual and neural correlates underlying experience gains with faces as they become familiar. PMID:25524650

  11. Social and Non-Social Visual Attention Patterns and Associative Learning in Infants at Risk for Autism

    ERIC Educational Resources Information Center

    Bhat, A. N.; Galloway, J. C.; Landa, R. J.

    2010-01-01

    Background: Social inattention is common in children with autism whereas associative learning capabilities are considered a relative strength. Identifying early precursors of impairment associated with autism could lead to earlier identification of this disorder. The present study compared social and non-social visual attention patterns as well as…

  12. Discrimination and Comprehension of Synthetic Speech by Students with Visual Impairments: The Case of Similar Acoustic Patterns

    ERIC Educational Resources Information Center

    Papadopoulos, Konstantinos; Argyropoulos, Vassilios S.; Kouroupetroglou, Georgios

    2008-01-01

    This study examined the perceptions held by sighted students and students with visual impairments of the intelligibility and comprehensibility of similar acoustic patterns produced by synthetic speech. It determined the types of errors the students made and compared the performance of the two groups on auditory discrimination and comprehension.

  13. Local Search and Information Visualization Methods for School Redistricting Marie desJardins, Blazej Bulka, Ryan Carr, Andrew Hunt, Priyang Rathod, and Penny Rheingans

    E-print Network

    Rheingans, Penny

    Local Search and Information Visualization Methods for School Redistricting Marie des: Emerging Applications Application Domain: School Redistricting AI Techniques and Issues: Heuristic Search of school redistricting, in which students are assigned to home schools within a county or school district

  14. The interplay of attention and consciousness in visual search, attentional blink and working memory consolidation.

    PubMed

    Raffone, Antonino; Srinivasan, Narayanan; van Leeuwen, Cees

    2014-05-01

    Despite the acknowledged relationship between consciousness and attention, theories of the two have mostly been developed separately. Moreover, these theories have independently attempted to explain phenomena in which both are likely to interact, such as the attentional blink (AB) and working memory (WM) consolidation. Here, we make an effort to bridge the gap between, on the one hand, a theory of consciousness based on the notion of global workspace (GW) and, on the other, a synthesis of theories of visual attention. We offer a theory of attention and consciousness (TAC) that provides a unified neurocognitive account of several phenomena associated with visual search, AB and WM consolidation. TAC assumes multiple processing stages between early visual representation and conscious access, and extends the dynamics of the global neuronal workspace model to a visual attentional workspace (VAW). The VAW is controlled by executive routers, higher-order representations of executive operations in the GW, without the need for explicit saliency or priority maps. TAC leads to newly proposed mechanisms for illusory conjunctions, AB, inattentional blindness and WM capacity, and suggests neural correlates of phenomenal consciousness. Finally, the theory reconciles the all-or-none and graded perspectives on conscious representation. PMID:24639586

  15. Searching for Truth: Internet Search Patterns as a Method of Investigating Online Responses to a Russian Illicit Drug Policy Debate

    PubMed Central

    Gillespie, James A; Quinn, Casey

    2012-01-01

    Background This is a methodological study investigating the online responses to a national debate over an important health and social problem in Russia. Russia is the largest Internet market in Europe, exceeding Germany in the absolute number of users. However, Russia is unusual in that the main search provider is not Google, but Yandex. Objective This study had two main objectives. First, to validate Yandex search patterns against those provided by Google, and second, to test this method's adequacy for investigating online interest in a 2010 national debate over Russian illicit drug policy. We hoped to learn what search patterns and specific search terms could reveal about the relative importance and geographic distribution of interest in this debate. Methods A national drug debate, centering on the anti-drug campaigner Egor Bychkov, was one of the main Russian domestic news events of 2010. Public interest in this episode was accompanied by increased Internet search. First, we measured the search patterns for 13 search terms related to the Bychkov episode and concurrent domestic events by extracting data from Google Insights for Search (GIFS) and Yandex WordStat (YaW). We conducted Spearman Rank Correlation of GIFS and YaW search data series. Second, we coded all 420 primary posts from Bychkov's personal blog between March 2010 and March 2012 to identify the main themes. Third, we compared GIFS and Yandex policies concerning the public release of search volume data. Finally, we established the relationship between salient drug issues and the Bychkov episode. Results We found a consistent pattern of strong to moderate positive correlations between Google and Yandex for the terms "Egor Bychkov" (r s = 0.88, P < .001), “Bychkov” (r s = .78, P < .001) and “Khimki”(r s = 0.92, P < .001). Peak search volumes for the Bychkov episode were comparable to other prominent domestic political events during 2010. Monthly search counts were 146,689 for “Bychkov” and 48,084 for “Egor Bychkov”, compared to 53,403 for “Khimki” in Yandex. We found Google potentially provides timely search results, whereas Yandex provides more accurate geographic localization. The correlation was moderate to strong between search terms representing the Bychkov episode and terms representing salient drug issues in Yandex–“illicit drug treatment” (r s = .90, P < .001), "illicit drugs" (r s = .76, P < .001), and "drug addiction" (r s = .74, P < .001). Google correlations were weaker or absent–"illicit drug treatment" (r s = .12, P = .58), “illicit drugs ” (r s = -0.29, P = .17), and "drug addiction" (r s = .68, P < .001). Conclusions This study contributes to the methodological literature on the analysis of search patterns for public health. This paper investigated the relationship between Google and Yandex, and contributed to the broader methods literature by highlighting both the potential and limitations of these two search providers. We believe that Yandex Wordstat is a potentially valuable, and underused data source for researchers working on Russian-related illicit drug policy and other public health problems. The Russian Federation, with its large, geographically dispersed, and politically engaged online population presents unique opportunities for studying the evolving influence of the Internet on politics and policy, using low cost methods resilient against potential increases in censorship. PMID:23238600

  16. Aging and Attentional Guidance During Visual Search: Functional Neuroanatomy by Positron Emission Tomography

    PubMed Central

    Madden, David J.; Turkington, Timothy G.; Provenzale, James M.; Denny, Laura L.; Langley, Linda K.; Hawk, Thomas C.; Coleman, R. Edward

    2007-01-01

    Positron emission tomography (PET) was used to examine adult age differences in neural activation during visual search. Target detection was less accurate for older adults than for younger adults, but both age groups were successful in using color to guide attention to a subset of display items. Increasing perceptual difficulty led to greater activation of occipitotemporal cortex for younger adults than for older adults, apparently as the result of older adults maintaining higher levels of activation within the easier task conditions. The results suggest that compensation for age-related decline in the efficiency of occipitotemporal cortical functioning was implemented by changes in the relative level of activation within this visual processing pathway, rather than by the recruitment of other cortical regions. PMID:11931285

  17. Visual assessment method of angular performance in medical liquid-crystal displays by use of the ANG test pattern: effect of ambient illuminance and effectiveness of modified scoring.

    PubMed

    Ikushima, Yoichiro; Morishita, Junji; Akamine, Hiroshi; Nakamura, Yasuhiko; Hashimoto, Noriyuki

    2014-01-01

    A visual assessment method of the angular performance in medical liquid-crystal displays (LCDs) by use of the "ANG test pattern" was proposed by Badano and the International Electrotechnical Commission. Our goals were to examine the effect of ambient illuminance on the visual assessment, and to investigate whether our modified visual assessment (with the ANG test pattern) can be used instead of the conventional assessment based on luminance measurements. As the ambient illuminance increased, the original scores obtained with the visual assessment decreased. The modified score of the visual assessment was in reasonable agreement with the results of the luminance-based assessment. We conclude that the visual assessment with the ANG test pattern should be performed in a room with constant ambient illuminance, and the modified visual assessment could have the potential to be used instead of the luminance-based assessment for quality assurance of medical LCDs. PMID:23934325

  18. 3D PATTERN OF BRAIN ABNORMALITIES IN WILLIAMS SYNDROME VISUALIZED USING TENSOR-BASED MORPHOMETRY

    PubMed Central

    Chiang, Ming-Chang; Reiss, Allan L.; Lee, Agatha D.; Bellugi, Ursula; Galaburda, Albert M.; Korenberg, Julie R.; Mills, Debra L.; Toga, Arthur W.; Thompson, Paul M.

    2009-01-01

    Williams syndrome (WS) is a neurodevelopmental disorder associated with deletion of ~20 contiguous genes in chromosome band 7q11.23. Individuals with WS exhibit mild to moderate mental retardation, but are relatively more proficient in specific language and musical abilities. We used tensor-based morphometry (TBM) to visualize the complex pattern of gray/white matter reductions in WS, based on fluid registration of structural brain images. Methods 3D T1-weighted brain MRIs of 41 WS subjects (age: 29.2±9.2SD years; 23F/18M) and 39 age-matched healthy controls (age: 27.5±7.4 years; 23F/16M) were fluidly registered to a minimum deformation target. Fine-scale volumetric differences were mapped between diagnostic groups. Local regions were identified where regional structure volumes were associated with diagnosis, and with intelligence quotient (IQ) scores. Brain asymmetry was also mapped and compared between diagnostic groups. Results WS subjects exhibited widely distributed brain volume reductions (~10–15% reduction; P < 0.0002, permutation test). After adjusting for total brain volume, the frontal lobes, anterior cingulate, superior temporal gyrus, amygdala, fusiform gyrus and cerebellum were found to be relatively preserved in WS, but parietal and occipital lobes, thalamus and basal ganglia, and midbrain were disproportionally decreased in volume (P < 0.0002). These regional volumes also correlated positively with performance IQ in adult WS subjects (age ? 30 years, P = 0.038). Conclusion TBM facilitates 3D visualization of brain volume reductions in WS. Reduced parietal/occipital volumes may be associated with visuospatial deficits in WS. By contrast, frontal lobes, amygdala, and cingulate gyrus are relatively preserved or even enlarged, consistent with unusual affect regulation and language production in WS. PMID:17512756

  19. Modeling peripheral visual acuity enables discovery of gaze strategies at multiple time scales during natural scene search

    PubMed Central

    Ramkumar, Pavan; Fernandes, Hugo; Kording, Konrad; Segraves, Mark

    2015-01-01

    Like humans, monkeys make saccades nearly three times a second. To understand the factors guiding this frequent decision, computational models of vision attempt to predict fixation locations using bottom-up visual features and top-down goals. How do the relative influences of these factors evolve over multiple time scales? Here we analyzed visual features at fixations using a retinal transform that provides realistic visual acuity by suitably degrading visual information in the periphery. In a task in which monkeys searched for a Gabor target in natural scenes, we characterized the relative importance of bottom-up and task-relevant influences by decoding fixated from nonfixated image patches based on visual features. At fast time scales, we found that search strategies can vary over the course of a single trial, with locations of higher saliency, target-similarity, edge–energy, and orientedness looked at later on in the trial. At slow time scales, we found that search strategies can be refined over several weeks of practice, and the influence of target orientation was significant only in the latter of two search tasks. Critically, these results were not observed without applying the retinal transform. Our results suggest that saccade-guidance strategies become apparent only when models take into account degraded visual representation in the periphery.

  20. Modeling peripheral visual acuity enables discovery of gaze strategies at multiple time scales during natural scene search.

    PubMed

    Ramkumar, Pavan; Fernandes, Hugo; Kording, Konrad; Segraves, Mark

    2015-01-01

    LIKE HUMANS, MONKEYS MAKE SACCADES NEARLY THREE TIMES A SECOND TO UNDERSTAND THE FACTORS GUIDING THIS FREQUENT DECISION, COMPUTATIONAL MODELS OF VISION ATTEMPT TO PREDICT FIXATION LOCATIONS USING BOTTOM-UP VISUAL FEATURES AND TOP-DOWN GOALS HOW DO THE RELATIVE INFLUENCES OF THESE FACTORS EVOLVE OVER MULTIPLE TIME SCALES? HERE WE ANALYZED VISUAL FEATURES AT FIXATIONS USING A RETINAL TRANSFORM THAT PROVIDES REALISTIC VISUAL ACUITY BY SUITABLY DEGRADING VISUAL INFORMATION IN THE PERIPHERY IN A TASK IN WHICH MONKEYS SEARCHED FOR A GABOR TARGET IN NATURAL SCENES, WE CHARACTERIZED THE RELATIVE IMPORTANCE OF BOTTOM-UP AND TASK-RELEVANT INFLUENCES BY DECODING FIXATED FROM NONFIXATED IMAGE PATCHES BASED ON VISUAL FEATURES AT FAST TIME SCALES, WE FOUND THAT SEARCH STRATEGIES CAN VARY OVER THE COURSE OF A SINGLE TRIAL, WITH LOCATIONS OF HIGHER SALIENCY, TARGET-SIMILARITY, EDGE-ENERGY, AND ORIENTEDNESS LOOKED AT LATER ON IN THE TRIAL AT SLOW TIME SCALES, WE FOUND THAT SEARCH STRATEGIES CAN BE REFINED OVER SEVERAL WEEKS OF PRACTICE, AND THE INFLUENCE OF TARGET ORIENTATION WAS SIGNIFICANT ONLY IN THE LATTER OF TWO SEARCH TASKS CRITICALLY, THESE RESULTS WERE NOT OBSERVED WITHOUT APPLYING THE RETINAL TRANSFORM OUR RESULTS SUGGEST THAT SACCADE-GUIDANCE STRATEGIES BECOME APPARENT ONLY WHEN MODELS TAKE INTO ACCOUNT DEGRADED VISUAL REPRESENTATION IN THE PERIPHERY. PMID:25814545

  1. Beam angle optimization for intensity-modulated radiation therapy using a guided pattern search method

    NASA Astrophysics Data System (ADS)

    Rocha, Humberto; Dias, Joana M.; Ferreira, Brígida C.; Lopes, Maria C.

    2013-05-01

    Generally, the inverse planning of radiation therapy consists mainly of the fluence optimization. The beam angle optimization (BAO) in intensity-modulated radiation therapy (IMRT) consists of selecting appropriate radiation incidence directions and may influence the quality of the IMRT plans, both to enhance better organ sparing and to improve tumor coverage. However, in clinical practice, most of the time, beam directions continue to be manually selected by the treatment planner without objective and rigorous criteria. The goal of this paper is to introduce a novel approach that uses beam’s-eye-view dose ray tracing metrics within a pattern search method framework in the optimization of the highly non-convex BAO problem. Pattern search methods are derivative-free optimization methods that require a few function evaluations to progress and converge and have the ability to better avoid local entrapment. The pattern search method framework is composed of a search step and a poll step at each iteration. The poll step performs a local search in a mesh neighborhood and ensures the convergence to a local minimizer or stationary point. The search step provides the flexibility for a global search since it allows searches away from the neighborhood of the current iterate. Beam’s-eye-view dose metrics assign a score to each radiation beam direction and can be used within the pattern search framework furnishing a priori knowledge of the problem so that directions with larger dosimetric scores are tested first. A set of clinical cases of head-and-neck tumors treated at the Portuguese Institute of Oncology of Coimbra is used to discuss the potential of this approach in the optimization of the BAO problem.

  2. iPixel: a visual content-based and semantic search engine for retrieving digitized mammograms by using collective intelligence.

    PubMed

    Alor-Hernández, Giner; Pérez-Gallardo, Yuliana; Posada-Gómez, Rubén; Cortes-Robles, Guillermo; Rodríguez-González, Alejandro; Aguilar-Laserre, Alberto A

    2012-09-01

    Nowadays, traditional search engines such as Google, Yahoo and Bing facilitate the retrieval of information in the format of images, but the results are not always useful for the users. This is mainly due to two problems: (1) the semantic keywords are not taken into consideration and (2) it is not always possible to establish a query using the image features. This issue has been covered in different domains in order to develop content-based image retrieval (CBIR) systems. The expert community has focussed their attention on the healthcare domain, where a lot of visual information for medical analysis is available. This paper provides a solution called iPixel Visual Search Engine, which involves semantics and content issues in order to search for digitized mammograms. iPixel offers the possibility of retrieving mammogram features using collective intelligence and implementing a CBIR algorithm. Our proposal compares not only features with similar semantic meaning, but also visual features. In this sense, the comparisons are made in different ways: by the number of regions per image, by maximum and minimum size of regions per image and by average intensity level of each region. iPixel Visual Search Engine supports the medical community in differential diagnoses related to the diseases of the breast. The iPixel Visual Search Engine has been validated by experts in the healthcare domain, such as radiologists, in addition to experts in digital image analysis. PMID:22656866

  3. Low target prevalence is a stubborn source of errors in visual search tasks

    PubMed Central

    Wolfe, Jeremy M.; Horowitz, Todd S.; Van Wert, Michael J.; Kenner, Naomi M.; Place, Skyler S.; Kibbi, Nour

    2009-01-01

    In visual search tasks, observers look for targets in displays containing distractors. Likelihood that targets will be missed varies with target prevalence, the frequency with which targets are presented across trials. Miss error rates are much higher at low target prevalence (1–2%) than at high prevalence (50%). Unfortunately, low prevalence is characteristic of important search tasks like airport security and medical screening where miss errors are dangerous. A series of experiments show this prevalence effect is very robust. In signal detection terms, the prevalence effect can be explained as a criterion shift and not a change in sensitivity. Several efforts to induce observers to adopt a better criterion fail. However, a regime of brief retraining periods with high prevalence and full feedback allows observers to hold a good criterion during periods of low prevalence with no feedback. PMID:17999575

  4. Tracking target and distractor processing in fixed-feature visual search: evidence from human electrophysiology.

    PubMed

    Jannati, Ali; Gaspar, John M; McDonald, John J

    2013-12-01

    Salient distractors delay visual search for less salient targets in additional-singleton tasks, even when the features of the stimuli are fixed across trials. According to the salience-driven selection hypothesis, this delay is due to an initial attentional deployment to the distractor. Recent event-related potential (ERP) studies found no evidence for salience-driven selection in fixed-feature search, but the methods employed were not optimized to isolate distractor ERP components such as the N2pc and distractor positivity (PD; indices of selection and suppression, respectively). Here, we isolated target and distractor ERPs in two fixed-feature search experiments. Participants searched for a shape singleton in the presence of a more-salient color singleton (Experiment 1) or for a color singleton in the presence of a less-salient shape singleton (Experiment 2). The salient distractor did not elicit an N2pc, but it did elicit a PD on fast-response trials. Furthermore, distractors had no effect on the timing of the target N2pc. These results indicate that (a) the distractor was prevented from engaging the attentional mechanism associated with N2pc, (b) the distractor did not interrupt the deployment of attention to the target, and (c) competition for attention can be resolved by suppressing locations of irrelevant items on a salience-based priority map. PMID:23527999

  5. Effect of sevoflurane concentration on visual evoked potentials with pattern stimulation in dogs.

    PubMed

    Ito, Yosuke; Maehara, Seiya; Itoh, Yoshiki; Hayashi, Miri; Kubo, Akira; Itami, Takaharu; Ishizuka, Tomohito; Tamura, Jun; Yamashita, Kazuto

    2015-03-01

    The purpose of this study was to investigate the effects of sevoflurane concentration on canine visual evoked potentials with pattern stimulation (P-VEPs). Six clinically normal laboratory-beagle dogs were used. The minimum alveolar concentration (MAC) of sevoflurane was detected from all subjects by tail clamp method. The refractive power of the right eyes of all subjects was corrected to -2 diopters after skiascopy. For P-VEP recording, the recording and reference electrode were positioned at inion and nasion, respectively, and the earth electrode was positioned on the inner surface. To grasp the state of CNS suppression objectively, the bispectral index (BIS) value was used. The stimulus pattern size and distance for VEP recording were constant, 50.3 arc-min and 50 cm, respectively. P-VEPs and BIS values were recorded under sevoflurane in oxygen inhalational anesthesia at 0.5, 1.0, 1.5, 2.0, 2.5 and 2.75 sevoflurane MAC. For analysis of P-VEP, the P100 implicit time and N75-P100 amplitude were estimated. P-VEPs were detected at 0.5 to 1.5 MAC in all dogs, and disappeared at 2.0 MAC in four dogs and at 2.5 and 2.75 MAC in one dog each. The BIS value decreased with increasing sevoflurane MAC, and burst suppression began to appear from 1.5 MAC. There was no significant change in P100 implicit time and N75-P100 amplitude with any concentration of sevoflurane. At concentrations around 1.5 MAC, which are used routinely to immobilize dogs, sevoflurane showed no effect on P-VEP. PMID:25373729

  6. Effect of sevoflurane concentration on visual evoked potentials with pattern stimulation in dogs

    PubMed Central

    ITO, Yosuke; MAEHARA, Seiya; ITOH, Yoshiki; HAYASHI, Miri; KUBO, Akira; ITAMI, Takaharu; ISHIZUKA, Tomohito; TAMURA, Jun; YAMASHITA, Kazuto

    2014-01-01

    The purpose of this study was to investigate the effects of sevoflurane concentration on canine visual evoked potentials with pattern stimulation (P-VEPs). Six clinically normal laboratory-beagle dogs were used. The minimum alveolar concentration (MAC) of sevoflurane was detected from all subjects by tail clamp method. The refractive power of the right eyes of all subjects was corrected to ?2 diopters after skiascopy. For P-VEP recording, the recording and reference electrode were positioned at inion and nasion, respectively, and the earth electrode was positioned on the inner surface. To grasp the state of CNS suppression objectively, the bispectral index (BIS) value was used. The stimulus pattern size and distance for VEP recording were constant, 50.3 arc-min and 50 cm, respectively. P-VEPs and BIS values were recorded under sevoflurane in oxygen inhalational anesthesia at 0.5, 1.0, 1.5, 2.0, 2.5 and 2.75 sevoflurane MAC. For analysis of P-VEP, the P100 implicit time and N75-P100 amplitude were estimated. P-VEPs were detected at 0.5 to 1.5 MAC in all dogs, and disappeared at 2.0 MAC in four dogs and at 2.5 and 2.75 MAC in one dog each. The BIS value decreased with increasing sevoflurane MAC, and burst suppression began to appear from 1.5 MAC. There was no significant change in P100 implicit time and N75-P100 amplitude with any concentration of sevoflurane. At concentrations around 1.5 MAC, which are used routinely to immobilize dogs, sevoflurane showed no effect on P-VEP. PMID:25373729

  7. Learning about Locomotion Patterns from Visualizations: Effects of Presentation Format and Realism

    ERIC Educational Resources Information Center

    Imhof, Birgit; Scheiter, Katharina; Gerjets, Peter

    2011-01-01

    The rapid development of computer graphics technology has made possible an easy integration of dynamic visualizations into computer-based learning environments. This study examines the relative effectiveness of dynamic visualizations, compared either to sequentially or simultaneously presented static visualizations. Moreover, the degree of realism…

  8. Brain Activity Patterns Uniquely Supporting Visual Feature Integration after Traumatic Brain Injury

    PubMed Central

    Raja Beharelle, Anjali; Tisserand, Danielle; Stuss, Donald T.; McIntosh, Anthony R.; Levine, Brian

    2011-01-01

    Traumatic brain injury (TBI) patients typically respond more slowly and with more variability than controls during tasks of attention requiring speeded reaction time. These behavioral changes are attributable, at least in part, to diffuse axonal injury (DAI), which affects integrated processing in distributed systems. Here we use a multivariate method sensitive to distributed neural activity to compare brain activity patterns of patients with chronic phase moderate to-severe TBI to those of controls during performance on a visual feature integration task assessing complex attentional processes that has previously shown sensitivity to TBI. The TBI patients were carefully screened to be free of large focal lesions that can affect performance and brain activation independently of DAI. The task required subjects to hold either one or three features of a Target in mind while suppressing responses to distracting information. In controls, the multi-feature condition activated a distributed network including limbic, prefrontal, and medial temporal structures. TBI patients engaged this same network in the single-feature and baseline conditions. In multi-feature presentations, TBI patients alone activated additional frontal, parietal, and occipital regions. These results are consistent with neuroimaging studies using tasks assessing different cognitive domains, where increased spread of brain activity changes was associated with TBI. Our results also extend previous findings that brain activity for relatively moderate task demands in TBI patients is similar to that associated with of high task demands in controls. PMID:22180740

  9. Pattern drilling exploration: Optimum pattern types and hole spacings when searching for elliptical shaped targets

    USGS Publications Warehouse

    Drew, L.J.

    1979-01-01

    In this study the selection of the optimum type of drilling pattern to be used when exploring for elliptical shaped targets is examined. The rhombic pattern is optimal when the targets are known to have a preferred orientation. Situations can also be found where a rectangular pattern is as efficient as the rhombic pattern. A triangular or square drilling pattern should be used when the orientations of the targets are unknown. The way in which the optimum hole spacing varies as a function of (1) the cost of drilling, (2) the value of the targets, (3) the shape of the targets, (4) the target occurrence probabilities was determined for several examples. Bayes' rule was used to show how target occurrence probabilities can be revised within a multistage pattern drilling scheme. ?? 1979 Plenum Publishing Corporation.

  10. Two-Phase Pattern Search-based Learning Method for Multi-layer Neural Network

    NASA Astrophysics Data System (ADS)

    Wang, Xugang; Tang, Zheng; Tamura, Hiroki; Ishii, Masahiro

    A new multi-layer artificial neural network learning algorithm based on pattern search method is proposed. The learning model has two phases-a pattern search phase, and a local minimum-escaping phase. In the pattern search phase, our method performs local search iteratively and minimize the error measure function along with the set of descent directions of the error measure directly and finds the nearest minima efficiently. When the network gets stuck in local minima, the local minimum-escaping phase attempts to fill up the valley by modifying temperature parameters in ascent direction of the error measure. Thus, the two phases are repeated until the network gets out of local minima. The learning model is designed to provide a very simple and effective means of searching the minima of objective function directly without any knowledge of its derivatives. We test this algorithm on benchmark problems, such as exclusive-or (XOR), parity, Arabic numerals recognition, function approximation problems and a real world classification task. For all problems, the systems are shown be trained efficiently by our method. As a simple direct search method, it can be applied in hardware implementations easily.

  11. Visual discrimination and short-term memory for random patterns in patients with a focal cortical lesion.

    PubMed

    Greenlee, M W; Koessler, M; Cornelissen, F W; Mergner, T

    1997-01-01

    Visual discrimination and short-term recognition memory for computer-generated random patterns were explored in 23 patients with a postsurgical lesion in one of the cortical hemispheres. Their results are compared with those of 23 age-matched volunteers. In a same-different forced-choice discrimination task, d' and log beta (measures of sensitivity and bias), as well as reaction time (RT) were determined. All participants viewed patterns defined either by luminance contrast or isoluminant red-green color contrast, the amplitude of which was adjusted to be 10 times the respective detection threshold level. Block patterns consisting of a 6 x 6 matrix of light and dark (red and green) checks were randomly configured on each presentation. They were presented in pairs, randomly in two visual quadrants for a duration of 200 msec. Three presentation conditions were used: simultaneous presentation of reference and test stimulus, sequential presentation with a short delay (interstimulus interval, ISI = 3 s), and sequential presentation with a long delay (ISI = 6 s). The results indicate that patients with a lesion in the occipitotemporal cortex, the superior temporal cortex and the frontal cortex were significantly impaired on both luminance-contrast and color-contrast pattern discrimination. Patients with damage in the anterior inferotemporal cortex showed no overall impairment. The results suggest that performance in visual discrimination and recognition memory tasks rely on distributed neural processes with more than one neocortical location. PMID:9143445

  12. Visual search and contextual cueing: differential effects in 10-year-old children and adults.

    PubMed

    Couperus, Jane W; Hunt, Ruskin H; Nelson, Charles A; Thomas, Kathleen M

    2011-02-01

    The development of contextual cueing specifically in relation to attention was examined in two experiments. Adult and 10-year-old participants completed a context cueing visual search task (Jiang & Chun, The Quarterly Journal of Experimental Psychology, 54A(4), 1105-1124, 2001) containing stimuli presented in an attended (e.g., red) and unattended (e.g., green) color. When the spatial configuration of stimuli in the attended and unattended color was invariant and consistently paired with the target location, adult reaction times improved, demonstrating learning. Learning also occurred if only the attended stimuli's configuration remained fixed. In contrast, while 10 year olds, like adults, showed incrementally slower reaction times as the number of attended stimuli increased, they did not show learning in the standard paradigm. However, they did show learning when the ratio of attended to unattended stimuli was high, irrespective of the total number of attended stimuli. Findings suggest children show efficient attentional guidance by color in visual search but differences in contextual cueing. PMID:21264739

  13. Long-term retention of skilled visual search following severe traumatic brain injury

    PubMed Central

    PAVAWALLA, SHITAL P.; SCHMITTER-EDGECOMBE, MAUREEN

    2007-01-01

    We examined the long-term retention of a learned automatic cognitive process in 17 severe TBI participants and 10 controls. Participants had initially received extensive consistent-mapping (CM) training (i.e., 3600 trials) in a semantic category visual search task (Schmitter-Edgecombe & Beglinger, 2001). Following CM training, TBI and control groups demonstrated dramatic performance improvements and the development of an automatic attention response (AAR), indicating task-specific and stimulus-specific skill learning. After a 5- or 10-month retention interval, participants in this study performed a New CM task and the originally trained CM task to assess for retention of task-specific and stimulus-specific visual search skills, respectively. No significant group differences were found in the level of retention for either skill type, indicating that individuals with severe TBI were able to retain the learned skills over a long-term retention interval at a level comparable to controls. Exploratory analyses revealed that TBI participants who returned at the 5-month retention interval showed nearly complete skill retention, and greater skill retention than TBI participants who returned at the 10-month interval, suggesting that “booster” or retraining sessions may be needed when a skill is not continuously in use. PMID:17064444

  14. Multimodal neuroimaging evidence linking memory and attention systems during visual search cued by context.

    PubMed

    Kasper, Ryan W; Grafton, Scott T; Eckstein, Miguel P; Giesbrecht, Barry

    2015-03-01

    Visual search can be facilitated by the learning of spatial configurations that predict the location of a target among distractors. Neuropsychological and functional magnetic resonance imaging (fMRI) evidence implicates the medial temporal lobe (MTL) memory system in this contextual cueing effect, and electroencephalography (EEG) studies have identified the involvement of visual cortical regions related to attention. This work investigated two questions: (1) how memory and attention systems are related in contextual cueing; and (2) how these systems are involved in both short- and long-term contextual learning. In one session, EEG and fMRI data were acquired simultaneously in a contextual cueing task. In a second session conducted 1 week later, EEG data were recorded in isolation. The fMRI results revealed MTL contextual modulations that were correlated with short- and long-term behavioral context enhancements and attention-related effects measured with EEG. An fMRI-seeded EEG source analysis revealed that the MTL contributed the most variance to the variability in the attention enhancements measured with EEG. These results support the notion that memory and attention systems interact to facilitate search when spatial context is implicitly learned. PMID:25586959

  15. Gene Expression Browser: large-scale and cross-experiment microarray data integration, management, search & visualization

    PubMed Central

    2010-01-01

    Background In the last decade, a large amount of microarray gene expression data has been accumulated in public repositories. Integrating and analyzing high-throughput gene expression data have become key activities for exploring gene functions, gene networks and biological pathways. Effectively utilizing these invaluable microarray data remains challenging due to a lack of powerful tools to integrate large-scale gene-expression information across diverse experiments and to search and visualize a large number of gene-expression data points. Results Gene Expression Browser is a microarray data integration, management and processing system with web-based search and visualization functions. An innovative method has been developed to define a treatment over a control for every microarray experiment to standardize and make microarray data from different experiments homogeneous. In the browser, data are pre-processed offline and the resulting data points are visualized online with a 2-layer dynamic web display. Users can view all treatments over control that affect the expression of a selected gene via Gene View, and view all genes that change in a selected treatment over control via treatment over control View. Users can also check the changes of expression profiles of a set of either the treatments over control or genes via Slide View. In addition, the relationships between genes and treatments over control are computed according to gene expression ratio and are shown as co-responsive genes and co-regulation treatments over control. Conclusion Gene Expression Browser is composed of a set of software tools, including a data extraction tool, a microarray data-management system, a data-annotation tool, a microarray data-processing pipeline, and a data search & visualization tool. The browser is deployed as a free public web service (http://www.ExpressionBrowser.com) that integrates 301 ATH1 gene microarray experiments from public data repositories (viz. the Gene Expression Omnibus repository at the National Center for Biotechnology Information and Nottingham Arabidopsis Stock Center). The set of Gene Expression Browser software tools can be easily applied to the large-scale expression data generated by other platforms and in other species. PMID:20727159

  16. Age and distraction are determinants of performance on a novel visual search task in aged Beagle dogs.

    PubMed

    Snigdha, Shikha; Christie, Lori-Ann; De Rivera, Christina; Araujo, Joseph A; Milgram, Norton W; Cotman, Carl W

    2012-02-01

    Aging has been shown to disrupt performance on tasks that require intact visual search and discrimination abilities in human studies. The goal of the present study was to determine if canines show age-related decline in their ability to perform a novel simultaneous visual search task. Three groups of canines were included: a young group (N?=?10; 3 to 4.5 years), an old group (N?=?10; 8 to 9.5 years), and a senior group (N?=?8; 11 to 15.3 years). Subjects were first tested for their ability to learn a simple two-choice discrimination task, followed by the visual search task. Attentional demands in the task were manipulated by varying the number of distracter items; dogs received an equal number of trials with either zero, one, two, or three distracters. Performance on the two-choice discrimination task varied with age, with senior canines making significantly more errors than the young. Performance accuracy on the visual search task also varied with age; senior animals were significantly impaired compared to both the young and old, and old canines were intermediate in performance between young and senior. Accuracy decreased significantly with added distracters in all age groups. These results suggest that aging impairs the ability of canines to discriminate between task-relevant and -irrelevant stimuli. This is likely to be derived from impairments in cognitive domains such as visual memory and learning and selective attention. PMID:21336566

  17. Complex Visual Search in Children and Adolescents: Effects of Age and Performance on fMRI Activation

    PubMed Central

    Lidzba, Karen; Ebner, Kathina; Hauser, Till-Karsten; Wilke, Marko

    2013-01-01

    Complex visuospatial processing relies on distributed neural networks involving occipital, parietal and frontal brain regions. Effects of physiological maturation (during normal brain development) and proficiency on tasks requiring complex visuospatial processing have not yet been studied extensively, as they are almost invariably interrelated. We therefore aimed at dissociating the effects of age and performance on functional MRI (fMRI) activation in a complex visual search task. In our cross-sectional study, healthy children and adolescents (n = 43, 19 females, 7-17 years) performed a complex visual search task during fMRI. Resulting activation was analysed with regard to the differential effects of age and performance. Our results are compatible with an increase in the neural network's efficacy with age: within occipital and parietal cortex, the core regions of the visual exploration network, activation increased with age, and more so in the right than in the left hemisphere. Further, activation outside the visual search network decreased with age, mainly in left inferior frontal, middle temporal, and inferior parietal cortex. High-performers had stronger activation in right superior parietal cortex, suggesting a more mature visual search network. We could not see effects of age or performance in frontal cortex. Our results show that effects of physiological maturation and effects of performance, while usually intertwined, can be successfully disentangled and investigated using fMRI in children and adolescents. PMID:24376871

  18. Visual Search as a Tool for a Quick and Reliable Assessment of Cognitive Functions in Patients with Multiple Sclerosis

    PubMed Central

    Utz, Kathrin S.; Hankeln, Thomas M. A.; Jung, Lena; Lämmer, Alexandra; Waschbisch, Anne; Lee, De-Hyung; Linker, Ralf A.; Schenk, Thomas

    2013-01-01

    Background Despite the high frequency of cognitive impairment in multiple sclerosis, its assessment has not gained entrance into clinical routine yet, due to lack of time-saving and suitable tests for patients with multiple sclerosis. Objective The aim of the study was to compare the paradigm of visual search with neuropsychological standard tests, in order to identify the test that discriminates best between patients with multiple sclerosis and healthy individuals concerning cognitive functions, without being susceptible to practice effects. Methods Patients with relapsing remitting multiple sclerosis (n = 38) and age-and gender-matched healthy individuals (n = 40) were tested with common neuropsychological tests and a computer-based visual search task, whereby a target stimulus has to be detected amongst distracting stimuli on a touch screen. Twenty-eight of the healthy individuals were re-tested in order to determine potential practice effects. Results Mean reaction time reflecting visual attention and movement time indicating motor execution in the visual search task discriminated best between healthy individuals and patients with multiple sclerosis, without practice effects. Conclusions Visual search is a promising instrument for the assessment of cognitive functions and potentially cognitive changes in patients with multiple sclerosis thanks to its good discriminatory power and insusceptibility to practice effects. PMID:24282604

  19. [Dipole sources localization of late components of event-related potentials during effective and ineffective visual search].

    PubMed

    Ermakov, P N; Babenko, V V; Bozhinskaia, M A

    2009-01-01

    The question concerning the mechanisms for choice of relevant information is disputable. One point of view is that competition of entrance information for selective attention may be parallel if a target has a distinguishing character. The other one suggests that a search for relevant information is always successive but takes different rates. We examined the relevancy of these approaches by means of comparison of cortical areas involved in a decision-making process in the visual search tasks realized with the different effectiveness. The method of the ERP dipole sources localization was used. The ERPs to images in visual search tasks with different "difficulty" were recorded. Distribution of cortical sources of the ERP late components was analyzed. A task complication resulted in an activity focus displacement from the occipital to frontal cortical areas. The results suggest different mechanisms for effective and ineffective search and testify that the processes of the relevant information selection may be simultaneous and successive. PMID:19795803

  20. Visual Search Strategies of Soccer Players Executing a Power vs. Placement Penalty Kick

    PubMed Central

    Timmis, Matthew A.; Turner, Kieran; van Paridon, Kjell N.

    2014-01-01

    Introduction When taking a soccer penalty kick, there are two distinct kicking techniques that can be adopted; a ‘power’ penalty or a ‘placement’ penalty. The current study investigated how the type of penalty kick being taken affected the kicker’s visual search strategy and where the ball hit the goal (end ball location). Method Wearing a portable eye tracker, 12 university footballers executed 2 power and placement penalty kicks, indoors, both with and without the presence of a goalkeeper. Video cameras were used to determine initial ball velocity and end ball location. Results When taking the power penalty, the football was kicked significantly harder and more centrally in the goal compared to the placement penalty. During the power penalty, players fixated on the football for longer and more often at the goalkeeper (and by implication the middle of the goal), whereas in the placement penalty, fixated longer at the goal, specifically the edges. Findings remained consistent irrespective of goalkeeper presence. Discussion/conclusion Findings indicate differences in visual search strategy and end ball location as a function of type of penalty kick. When taking the placement penalty, players fixated and kicked the football to the edges of the goal in an attempt to direct the ball to an area that the goalkeeper would have difficulty reaching and saving. Fixating significantly longer on the football when taking the power compared to placement penalty indicates a greater importance of obtaining visual information from the football. This can be attributed to ensuring accurate foot-to-ball contact and subsequent generation of ball velocity. Aligning gaze and kicking the football centrally in the goal when executing the power compared to placement penalty may have been a strategy to reduce the risk of kicking wide of the goal altogether. PMID:25517405

  1. The role of pattern recognition in creative problem solving: a case study in search of new mathematics for biology.

    PubMed

    Hong, Felix T

    2013-09-01

    Rosen classified sciences into two categories: formalizable and unformalizable. Whereas formalizable sciences expressed in terms of mathematical theories were highly valued by Rutherford, Hutchins pointed out that unformalizable parts of soft sciences are of genuine interest and importance. Attempts to build mathematical theories for biology in the past century was met with modest and sporadic successes, and only in simple systems. In this article, a qualitative model of humans' high creativity is presented as a starting point to consider whether the gap between soft and hard sciences is bridgeable. Simonton's chance-configuration theory, which mimics the process of evolution, was modified and improved. By treating problem solving as a process of pattern recognition, the known dichotomy of visual thinking vs. verbal thinking can be recast in terms of analog pattern recognition (non-algorithmic process) and digital pattern recognition (algorithmic process), respectively. Additional concepts commonly encountered in computer science, operations research and artificial intelligence were also invoked: heuristic searching, parallel and sequential processing. The refurbished chance-configuration model is now capable of explaining several long-standing puzzles in human cognition: a) why novel discoveries often came without prior warning, b) why some creators had no ideas about the source of inspiration even after the fact, c) why some creators were consistently luckier than others, and, last but not least, d) why it was so difficult to explain what intuition, inspiration, insight, hunch, serendipity, etc. are all about. The predictive power of the present model was tested by means of resolving Zeno's paradox of Achilles and the Tortoise after one deliberately invoked visual thinking. Additional evidence of its predictive power must await future large-scale field studies. The analysis was further generalized to constructions of scientific theories in general. This approach is in line with Campbell's evolutionary epistemology. Instead of treating science as immutable Natural Laws, which already existed and which were just waiting to be discovered, scientific theories are regarded as humans' mental constructs, which must be invented to reconcile with observed natural phenomena. In this way, the pursuit of science is shifted from diligent and systematic (or random) searching for existing Natural Laws to firing up humans' imagination to comprehend Nature's behavioral pattern. The insights gained in understanding human creativity indicated that new mathematics that is capable of handling effectively parallel processing and human subjectivity is sorely needed. The past classification of formalizability vs. non-formalizability was made in reference to contemporary mathematics. Rosen's conclusion did not preclude future inventions of new biology-friendly mathematics. PMID:23597605

  2. Searching for a major locus for male pattern baldness (MPB)

    Microsoft Academic Search

    R. Anker; A. Z. Eisen; H. Donis-Keller

    1994-01-01

    Male pattern baldness (MPB) is a common trait in post-pubertal males. Approximately 50% of adult males present some degree of MPB by age 50. According to the classification provided by Hamilton in 1951 and modified by Norwood in 1975, the trait itself is a continuum that ranges from mild (Type I) to severe (Type VII) cases. In addition, there is

  3. Pattern-based Similarity Search for Microarray Data Haixun Wang

    E-print Network

    Pei, Jian

    - ciently quantify the similarity between two objects in a meaningful way. In DNA microarray analysis microarray analy- sis [1, 8, 7]. A DNA microarray is a two dimensional matrix where entry dij represents near neighbors based on subspace pattern similarity is important to many applications including DNA

  4. Depth Depending Pattern Recognition (DDPR) - a tool for visualization of spatial and temporal similarities of properties in sediment cores

    NASA Astrophysics Data System (ADS)

    Büttner, Olaf; Baborowski, Martina

    2013-04-01

    Depth Depending Pattern Recognition (DDPR) is a new simple tool for the visualization of spatial and temporal similarities of measured parameters in a set of sediment cores. It was developed to support the multivariate analysis of data of sediment cores taken in a still water area of the River Elbe [1]. The idea behind is the assumption that correlations in spatial or temporal distributions of environmental parameters can be visualized by different ways and that a distance between two patterns can be defined with mathematical methods. So the similarity of two patterns can be quantified and assessed by a catalog of subjective rules. Generally, defining one reference pattern, the computation of a distance matrix for different parameter distributions is easily possible. Consequently, the three main steps of the algorithm are a) the creation of the pattern from the measurements, b) the definition of the distance calculation and c) the interpretation and assessment of the distance matrix. The method can be used in addition to classical uni- or multivariate statistical methods like regression analysis, principal component analysis, correlation analysis etc. DDPR supports hypothesis testing and explanation of relationships. In the poster DDPR is explained and the method is presented for two examples, an artificial one and one with data from sediment cores. Reference [1] Baborowski M., Büttner O., Morgenstern P., Jancke T., Westrich B. (2012) Spatial variability of metal pollution in groyne fields of the Middle Elbe - Implications for sediment monitoring, Environmental Pollution, 167,115-123

  5. Correlation-maximizing surrogate gene space for visual mining of gene expression patterns in developing barley endosperm tissue

    PubMed Central

    Strickert, Marc; Sreenivasulu, Nese; Usadel, Björn; Seiffert, Udo

    2007-01-01

    Background Micro- and macroarray technologies help acquire thousands of gene expression patterns covering important biological processes during plant ontogeny. Particularly, faithful visualization methods are beneficial for revealing interesting gene expression patterns and functional relationships of coexpressed genes. Such screening helps to gain deeper insights into regulatory behavior and cellular responses, as will be discussed for expression data of developing barley endosperm tissue. For that purpose, high-throughput multidimensional scaling (HiT-MDS), a recent method for similarity-preserving data embedding, is substantially refined and used for (a) assessing the quality and reliability of centroid gene expression patterns, and for (b) derivation of functional relationships of coexpressed genes of endosperm tissue during barley grain development (0–26 days after flowering). Results Temporal expression profiles of 4824 genes at 14 time points are faithfully embedded into two-dimensional displays. Thereby, similar shapes of coexpressed genes get closely grouped by a correlation-based similarity measure. As a main result, by using power transformation of correlation terms, a characteristic cloud of points with bipolar sandglass shape is obtained that is inherently connected to expression patterns of pre-storage, intermediate and storage phase of endosperm development. Conclusion The new HiT-MDS-2 method helps to create global views of expression patterns and to validate centroids obtained from clustering programs. Furthermore, functional gene annotation for developing endosperm barley tissue is successfully mapped to the visualization, making easy localization of major centroids of enriched functional categories possible. PMID:17519012

  6. Color pattern-reversal visual evoked potential in eyes with ocular hypertension and primary open-angle glaucoma

    Microsoft Academic Search

    Yi-Hao Shih; Zhu-Jing Huang; Ching-E Chang

    1991-01-01

    Color pattern-reversal visual evoked potential testing was performed in 99 normal eyes, 27 eyes with ocular hypertension and 30 eyes with primary open-angle glaucoma with the use of black-white, black-red and black-blue color checkerboard stimuli. The PI wave peak time and amplitude of the eyes with ocular hypertension and glaucoma were significantly different from those of age-similar normal eyes, especially

  7. Identifying Shared Genetic Structure Patterns among Pacific Northwest Forest Taxa: Insights from Use of Visualization Tools and Computer Simulations

    Microsoft Academic Search

    Mark P. Miller; Susan M. Haig

    2010-01-01

    BackgroundIdentifying causal relationships in phylogeographic and landscape genetic investigations is notoriously difficult, but can be facilitated by use of multispecies comparisons.Methodology\\/Principal FindingsWe used data visualizations to identify common spatial patterns within single lineages of four taxa inhabiting Pacific Northwest forests (northern spotted owl: Strix occidentalis caurina; red tree vole: Arborimus longicaudus; southern torrent salamander: Rhyacotriton variegatus; and western white pine:

  8. The effects of action video game experience on the time course of inhibition of return and the efficiency of visual search

    Microsoft Academic Search

    Alan D. Castel; Jay Pratt; Emily Drummond

    2005-01-01

    The ability to efficiently search the visual environment is a critical function of the visual system, and recent research has shown that experience playing action video games can influence visual selective attention. The present research examined the similarities and differences between video game players (VGPs) and non-video game players (NVGPs) in terms of the ability to inhibit attention from returning

  9. Development of a Web GIS Application for Visualizing and Analyzing Community Out of Hospital Cardiac Arrest Patterns

    PubMed Central

    Semple, Hugh; Qin, Han; Sasson, Comilla

    2013-01-01

    Improving survival rates at the neighborhood level is increasingly seen as a priority for reducing overall rates of out-of-hospital cardiac arrest (OHCA) in the United States. Since wide disparities exist in OHCA rates at the neighborhood level, it is important for public health officials and residents to be able to quickly locate neighborhoods where people are at elevated risk for cardiac arrest and to target these areas for educational outreach and other mitigation strategies. This paper describes an OHCA web mapping application that was developed to provide users with interactive maps and data for them to quickly visualize and analyze the geographic pattern of cardiac arrest rates, bystander CPR rates, and survival rates at the neighborhood level in different U.S. cities. The data comes from the CARES Registry and is provided over a period spanning several years so users can visualize trends in neighborhood out-of-hospital cardiac arrest patterns. Users can also visualize areas that are statistical hot and cold spots for cardiac arrest and compare OHCA and bystander CPR rates in the hot and cold spots. Although not designed as a public participation GIS (PPGIS), this application seeks to provide a forum around which data and maps about local patterns of OHCA can be shared, analyzed and discussed with a view of empowering local communities to take action to address the high rates of OHCA in their vicinity. PMID:23923097

  10. A Performance Analysis of Evolutionary Pattern Search with Generalized Mutation Steps

    E-print Network

    Sadeh, Norman M.

    A Performance Analysis of Evolutionary Pattern Search with Generalized Mutation Steps William E performance of EPSAs. This paper re- visits that analysis and extends it to a more general model of mutation. We evaluate experimentally how the choice of the set of mutation offsets affects optimization perfor

  11. In Search of Naming Patterns: A Survey of Finnish Lake Names

    E-print Network

    Leino, Antti

    1 In Search of Naming Patterns: A Survey of Finnish Lake Names Antti Leino University of Helsinki is an attempt to address the issue: the goals were, first, to find regularities in the naming of Finnish lakes Finnish lake names found on the 1:20 000 Basic Map. These revealed several groups of names that appear

  12. Information Search Patterns of Business Communities: A Comparison Between Small and Medium-sized Businesses

    Microsoft Academic Search

    Liwen Qiu Vaughan

    1997-01-01

    To identify the information search patterns of business communities, two surveys were conducted, one aimed at small businesses and the other at medium-sized businesses. Use of different information sources, especially the public library, for business purposes were examined. Results show that businesses obtain information more through informal sources than formal ones. The customer is the most important business information source.

  13. Flexible Feature-Based Inhibition in Visual Search Mediates Magnified Impairments of Selection: Evidence from Carry-Over Effects under Dynamic Preview-Search Conditions

    ERIC Educational Resources Information Center

    Andrews, Lucy S.; Watson, Derrick G.; Humphreys, Glyn W.; Braithwaite, Jason J.

    2011-01-01

    Evidence for inhibitory processes in visual search comes from studies using preview conditions, where responses to new targets are delayed if they carry a featural attribute belonging to the old distractor items that are currently being ignored--the negative carry-over effect (Braithwaite, Humphreys, & Hodsoll, 2003). We examined whether…

  14. The Relationship between Arithmetic and Reading Achievement and Visual Pattern Recognition in First Grade Children.

    ERIC Educational Resources Information Center

    Bragman, Ruth; Hardy, Robert C.

    1982-01-01

    Results from testing 20 first graders in a remedial class in Maryland indicated that: same pattern recognition was significantly higher than reverse pattern recognition; identical pattern recognition did not affect performance on reading and arithmetic achievement; reverse pattern recognition significantly affected performance on reading and…

  15. Spatial Attention can Bias Search in Visual Short-Term Memory

    PubMed Central

    Nobre, Anna C.; Griffin, Ivan C.; Rao, Anling

    2007-01-01

    Whereas top-down attentional control is known to bias perceptual functions at many levels of stimulus analysis, its possible influence over memory-related functions remains uncharted. Our experiment combined behavioral measures and event-related potentials (ERPs) to test the ability of spatial orienting to bias functions associated with visual short-term memory (VSTM), and to shed light on the neural mechanisms involved. In particular, we investigated whether orienting attention to a spatial location within an array maintained in VSTM could facilitate the search for a specific remembered item. Participants viewed arrays of one, two or four differently colored items, followed by an informative spatial (100% valid) or uninformative neutral retro-cue (1500–2500?ms after the array), and later by a probe stimulus (500–1000?ms after the retro-cue). The task was to decide whether the probe stimulus had been present in the array. Behavioral results showed that spatial retro-cues improved both accuracy and response times for making decisions about the presence of the probe item in VSTM, and significantly attenuated performance decrements caused by increasing VSTM load. We also identified a novel ERP component (N3RS) specifically associated with searching for an item within VSTM. Paralleling the behavioral results, the amplitude and duration of the N3RS systematically increased with VSTM load in neutral retro-cue trials. When spatial retro-cues were provided, this “retro-search” component was absent. Our findings clearly show that the influence of top-down attentional biases extends to mnemonic functions, and, specifically, that searching for items within VSTM can be under flexible voluntary control. PMID:18958218

  16. Neurofilament protein defines regional patterns of cortical organization in the macaque monkey visual system: a quantitative immunohistochemical analysis

    NASA Technical Reports Server (NTRS)

    Hof, P. R.; Morrison, J. H.; Bloom, F. E. (Principal Investigator)

    1995-01-01

    Visual function in monkeys is subserved at the cortical level by a large number of areas defined by their specific physiological properties and connectivity patterns. For most of these cortical fields, a precise index of their degree of anatomical specialization has not yet been defined, although many regional patterns have been described using Nissl or myelin stains. In the present study, an attempt has been made to elucidate the regional characteristics, and to varying degrees boundaries, of several visual cortical areas in the macaque monkey using an antibody to neurofilament protein (SMI32). This antibody labels a subset of pyramidal neurons with highly specific regional and laminar distribution patterns in the cerebral cortex. Based on the staining patterns and regional quantitative analysis, as many as 28 cortical fields were reliably identified. Each field had a homogeneous distribution of labeled neurons, except area V1, where increases in layer IVB cell and in Meynert cell counts paralleled the increase in the degree of eccentricity in the visual field representation. Within the occipitotemporal pathway, areas V3 and V4 and fields in the inferior temporal cortex were characterized by a distinct population of neurofilament-rich neurons in layers II-IIIa, whereas areas located in the parietal cortex and part of the occipitoparietal pathway had a consistent population of large labeled neurons in layer Va. The mediotemporal areas MT and MST displayed a distinct population of densely labeled neurons in layer VI. Quantitative analysis of the laminar distribution of the labeled neurons demonstrated that the visual cortical areas could be grouped in four hierarchical levels based on the ratio of neuron counts between infragranular and supragranular layers, with the first (areas V1, V2, V3, and V3A) and third (temporal and parietal regions) levels characterized by low ratios and the second (areas MT, MST, and V4) and fourth (frontal regions) levels characterized by high to very high ratios. Such density trends may correspond to differential representation of corticocortically (and corticosubcortically) projecting neurons at several functional steps in the integration of the visual stimuli. In this context, it is possible that neurofilament protein is crucial for the unique capacity of certain subsets of neurons to perform the highly precise mapping functions of the monkey visual system.

  17. Scan Patterns Predict Sentence Production in the Cross-Modal Processing of Visual Scenes

    ERIC Educational Resources Information Center

    Coco, Moreno I.; Keller, Frank

    2012-01-01

    Most everyday tasks involve multiple modalities, which raises the question of how the processing of these modalities is coordinated by the cognitive system. In this paper, we focus on the coordination of visual attention and linguistic processing during speaking. Previous research has shown that objects in a visual scene are fixated before they…

  18. Tracking fear in snake and spider fearful participants during visual search: A multi-response domain study

    E-print Network

    Caldara, Roberto

    Tracking fear in snake and spider fearful participants during visual search: A multi snake or spider fearful participants showed shorter reaction times (RTs) to respond to their feared animal (e.g., snake) than to the nonfeared animal (i.e., spider) (O¨ hman, Flykt, & Esteves, 2001). Here

  19. Age-Related Occipito-Temporal Hypoactivation during Visual Search: Relationships between mN2pc Sources and Performance

    ERIC Educational Resources Information Center

    Lorenzo-Lopez, L.; Gutierrez, R.; Moratti, S.; Maestu, F.; Cadaveira, F.; Amenedo, E.

    2011-01-01

    Recently, an event-related potential (ERP) study (Lorenzo-Lopez et al., 2008) provided evidence that normal aging significantly delays and attenuates the electrophysiological correlate of the allocation of visuospatial attention (N2pc component) during a feature-detection visual search task. To further explore the effects of normal aging on the…

  20. The contribution of coping-related variables and heart rate variability to visual search performance under pressure.

    PubMed

    Laborde, Sylvain; Lautenbach, Franziska; Allen, Mark S

    2015-02-01

    Visual search performance under pressure is explored within the predictions of the neurovisceral integration model. The experimental aims of this study were: 1) to investigate the contribution of coping-related variables to baseline, task, and reactivity (task-baseline) high-frequency heart rate variability (HF-HRV), and 2) to investigate the contribution of coping-related variables and HF-HRV to visual search performance under pressure. Participants (n=96) completed self-report measures of coping-related variables (emotional intelligence, coping style, perceived stress intensity, perceived control of stress, coping effectiveness, challenge and threat, and attention strategy) and HF-HRV was measured during a visual search task under pressure. The data show that baseline HF-HRV was predicted by a trait coping-related variable, task HF-HRV was predicted by a combination of trait and state coping-related variables, and reactivity HF-HRV was predicted by a state coping-related variable. Visual search performance was predicted by coping-related variables but not by HF-HRV. PMID:25481358

  1. Effects of Interior Bezels of Tiled-Monitor Large Displays on Visual Search, Tunnel Steering, and Target Selection

    E-print Network

    Balakrishnan, Ravin

    in various application domains. However, how their interior bezels affect user performance and behavior has-tunnel steering, but not to target selection. In addition, we discuss how inte- rior bezels affect user behaviors understand bezel effects on user performances and behaviors in visual search, straight tunnel steering

  2. Search for ?±± with new decay patterns at the LHC

    NASA Astrophysics Data System (ADS)

    Chen, Chuan-Hung; Nomura, Takaaki

    2015-02-01

    A search for the doubly charged Higgs (?±±) is performed in the two-Higgs-doublet extension of the conventional type-II seesaw model. We find that a fantastic mixing effect between the singly charged Higgses of the Higgs doublet and triplet arises from the scalar potential. The mixing leads to the following intriguing phenomena: (i) the mass splittings in triplet particles are magnified; (ii) QCD processes dominate the production of ?±±; and (iii) the new predominant decay channels of ?±± are ?±±?W±[*]H1(2 ) ±(*) , but not ?±?(?±?±,W±W±) , which are usually discussed in the literature. With a luminosity of 40 fb-1 and collision energy of 13 TeV, we demonstrate that a ?±± with mass below 330 GeV could be observed at the 5 ? level. Moreover, when the luminosity approaches 300 fb-1 , the observed mass of ?±± could reach up to 450 GeV.

  3. Target templates: the precision of mental representations affects attentional guidance and decision-making in visual search

    PubMed Central

    Hout, Michael C.; Goldinger, Stephen D.

    2014-01-01

    When people look for things in the environment, they use target templates—mental representations of the objects they are attempting to locate—to guide attention and to assess incoming visual input as potential targets. However, unlike laboratory participants, searchers in the real world rarely have perfect knowledge regarding the potential appearance of targets. In seven experiments, we examined how the precision of target templates affects the ability to conduct visual search. Specifically, we degraded template precision in two ways: 1) by contaminating searchers’ templates with inaccurate features, and 2) by introducing extraneous features to the template that were unhelpful. We recorded eye movements to allow inferences regarding the relative extents to which attentional guidance and decision-making are hindered by template imprecision. Our findings support a dual-function theory of the target template and highlight the importance of examining template precision in visual search. PMID:25214306

  4. HSI-Find: A Visualization and Search Service for Terascale Spectral Image Catalogs

    NASA Astrophysics Data System (ADS)

    Thompson, D. R.; Smith, A. T.; Castano, R.; Palmer, E. E.; Xing, Z.

    2013-12-01

    Imaging spectrometers are remote sensing instruments commonly deployed on aircraft and spacecraft. They provide surface reflectance in hundreds of wavelength channels, creating data cubes known as hyperspecrtral images. They provide rich compositional information making them powerful tools for planetary and terrestrial science. These data products can be challenging to interpret because they contain datapoints numbering in the thousands (Dawn VIR) or millions (AVIRIS-C). Cross-image studies or exploratory searches involving more than one scene are rare; data volumes are often tens of GB per image and typical consumer-grade computers cannot store more than a handful of images in RAM. Visualizing the information in a single scene is challenging since the human eye can only distinguish three color channels out of the hundreds available. To date, analysis has been performed mostly on single images using purpose-built software tools that require extensive training and commercial licenses. The HSIFind software suite provides a scalable distributed solution to the problem of visualizing and searching large catalogs of spectral image data. It consists of a RESTful web service that communicates to a javascript-based browser client. The software provides basic visualization through an intuitive visual interface, allowing users with minimal training to explore the images or view selected spectra. Users can accumulate a library of spectra from one or more images and use these to search for similar materials. The result appears as an intensity map showing the extent of a spectral feature in a scene. Continuum removal can isolate diagnostic absorption features. The server-side mapping algorithm uses an efficient matched filter algorithm that can process a megapixel image cube in just a few seconds. This enables real-time interaction, leading to a new way of interacting with the data: the user can launch a search with a single mouse click and see the resulting map in seconds. This allows the user to quickly explore each image, ascertain the main units of surface material, localize outliers, and develop an understanding of the various materials' spectral characteristics. The HSIFind software suite is currently in beta testing at the Planetary Science Institute and a process is underway to release it under an open source license to the broader community. We believe it will benefit instrument operations during remote planetary exploration, where tactical mission decisions demand rapid analysis of each new dataset. The approach also holds potential for public spectral catalogs where its shallow learning curve and portability can make these datasets accessible to a much wider range of researchers. Acknowledgements: The HSIFind project acknowledges the NASA Advanced MultiMission Operating System (AMMOS) and the Multimission Ground Support Services (MGSS). E. Palmer is with the Planetary Science Institute, Tucson, AZ. Other authors are with the Jet Propulsion Laboratory, Pasadena, CA. This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology under a contract with the National Aeronautics and Space Administration. Copyright 2013, California Institute of Technology.

  5. Pattern recognition-assisted infrared library searching of automotive clear coats.

    PubMed

    Fasasi, Ayuba; Mirjankar, Nikhil; Stoian, Razvan-Ionut; White, Collin; Allen, Matthew; Sandercock, Mark P; Lavine, Barry K

    2015-01-01

    Pattern recognition techniques have been developed to search the infrared (IR) spectral libraries of the paint data query (PDQ) database to differentiate between similar but nonidentical IR clear coat paint spectra. The library search system consists of two separate but interrelated components: search prefilters to reduce the size of the IR library to a specific assembly plant or plants corresponding to the unknown paint sample and a cross-correlation searching algorithm to identify IR spectra most similar to the unknown in the subset of spectra identified by the prefilters. To develop search prefilters with the necessary degree of accuracy, IR spectra from the PDQ database were preprocessed using wavelets to enhance subtle but significant features in the data. Wavelet coefficients characteristic of the assembly plant of the vehicle were identified using a genetic algorithm for pattern recognition and feature selection. A search algorithm was then used to cross-correlate the unknown with each IR spectrum in the subset of library spectra identified by the search prefilters. Each cross-correlated IR spectrum was simultaneously compared to an autocorrelated IR spectrum of the unknown using several spectral windows that span different regions of the cross-correlated and autocorrelated data from the midpoint. The top five hits identified in each search window are compiled, and a histogram is computed that summarizes the frequency of occurrence for each selected library sample. The five library samples with the highest frequency of occurrence are selected as potential hits. Even in challenging trials where the clear coat paint samples evaluated were all the same make (e.g., General Motors) within a limited production year range, the model of the automobile from which the unknown paint sample was obtained could be identified from its IR spectrum. PMID:25506887

  6. How Exact is Exact? In visual search a re-sized, re-oriented, or mirrored cue is just as effective as an exact cue.

    E-print Network

    it will be ahead of time makes your search even quicker. 0 250 500 750 1000 1250 1500 N=12 No Cue Word Cue Picture) behave like Word Cues. In search among heterogeneous items (photorealistic pictures, as hereHow Exact is Exact? In visual search a re-sized, re-oriented, or mirrored cue is just as effective

  7. Decoding and encoding of visual patterns using magnetoencephalographic data represented in manifolds.

    PubMed

    Kuo, Po-Chih; Chen, Yong-Sheng; Chen, Li-Fen; Hsieh, Jen-Chuen

    2014-11-15

    Visual decoding and encoding are crucial aspects in investigating the representation of visual information in the human brain. This paper proposes a bidirectional model for decoding and encoding of visual stimulus based on manifold representation of the temporal and spatial information extracted from magnetoencephalographic data. In the proposed decoding process, principal component analysis is applied to extract temporal principal components (TPCs) from the visual cortical activity estimated by a beamforming method. The spatial distribution of each TPC is in a high-dimensional space and can be mapped to the corresponding spatiotemporal component (STC) on a low-dimensional manifold. Once the linear mapping between the STC and the wavelet coefficients of the stimulus image is determined, the decoding process can synthesize an image resembling the stimulus image. The encoding process is performed by reversing the mapping or transformation in the decoding model and can predict the spatiotemporal brain activity from a stimulus image. In our experiments using visual stimuli containing eleven combinations of checkerboard patches, the information of spatial layout in the stimulus image was revealed in the embedded manifold. The correlation between the reconstructed and original images was 0.71 and the correlation map between the predicted and original brain activity was highly correlated to the map between the original brain activity for different stimuli (r=0.89). These results suggest that the temporal component is important in visual processing and manifolds can well represent the information related to visual perception. PMID:25072391

  8. Identification and functional characterization of two patterning genes, Zic4 and Ten_m3, in topographic map formation of the visual pathway

    E-print Network

    Horng, Sam H

    2010-01-01

    A central feature of visual pathway development is its organization into retinotopic maps. The developmental process by which these maps form involves a transition from early patterning cues to arrays of axonal guidance ...

  9. Flexible feature-based inhibition in visual search mediates magnified impairments of selection: evidence from carry-over effects under dynamic preview-search conditions.

    PubMed

    Andrews, Lucy S; Watson, Derrick G; Humphreys, Glyn W; Braithwaite, Jason J

    2011-08-01

    Evidence for inhibitory processes in visual search comes from studies using preview conditions, where responses to new targets are delayed if they carry a featural attribute belonging to the old distractor items that are currently being ignored-the negative carry-over effect (Braithwaite, Humphreys, & Hodsoll, 2003). We examined whether inhibition was applied in the same manner across different types of displays or whether the inhibitory weighting applied to different features varied with their utility for the search task. To test this, we present the first empirical investigation of negative carry-over effects under the ecologically valid conditions of dynamic visual search. Experiment 1 investigated preview search using dynamic moving and static displays. Detection was very poor when new targets carried the color of the old distractors, and this negative carry-over effect was significantly exaggerated with moving, compared with static, displays. Experiments 2a and 2b demonstrated that this effect could not be attributed to an increased role of preattentive grouping between new and old items for dynamic displays. Collectively, the findings suggest that feature-based inhibition contributes strongly to preview search through dynamic displays, and this leads to an amplified attentional blindness to new targets. The data specifically indicate that inhibitory processes in search differentially weight color and location in moving and static displays, and that feature-based inhibition may underlie many instances of sustained inattentional blindness in everyday life. PMID:21553995

  10. A Visual Language for Design Pattern Modelling and Instantiation David Maplesden

    E-print Network

    Grundy, John

    by the seminal "Gang of Four" book (Gamma et al, 1994) and Coplien's Software Patterns #12;(Coplien, 1996). Design patterns have become very widely used in object-oriented software development, and their influence

  11. Scavengers on the Move: Behavioural Changes in Foraging Search Patterns during the Annual Cycle

    PubMed Central

    López-López, Pascual; Benavent-Corai, José; García-Ripollés, Clara; Urios, Vicente

    2013-01-01

    Background Optimal foraging theory predicts that animals will tend to maximize foraging success by optimizing search strategies. However, how organisms detect sparsely distributed food resources remains an open question. When targets are sparse and unpredictably distributed, a Lévy strategy should maximize foraging success. By contrast, when resources are abundant and regularly distributed, simple Brownian random movement should be sufficient. Although very different groups of organisms exhibit Lévy motion, the shift from a Lévy to a Brownian search strategy has been suggested to depend on internal and external factors such as sex, prey density, or environmental context. However, animal response at the individual level has received little attention. Methodology/Principal Findings We used GPS satellite-telemetry data of Egyptian vultures Neophron percnopterus to examine movement patterns at the individual level during consecutive years, with particular interest in the variations in foraging search patterns during the different periods of the annual cycle (i.e. breeding vs. non-breeding). Our results show that vultures followed a Brownian search strategy in their wintering sojourn in Africa, whereas they exhibited a more complex foraging search pattern at breeding grounds in Europe, including Lévy motion. Interestingly, our results showed that individuals shifted between search strategies within the same period of the annual cycle in successive years. Conclusions/Significance Results could be primarily explained by the different environmental conditions in which foraging activities occur. However, the high degree of behavioural flexibility exhibited during the breeding period in contrast to the non-breeding period is challenging, suggesting that not only environmental conditions explain individuals' behaviour but also individuals' cognitive abilities (e.g., memory effects) could play an important role. Our results support the growing awareness about the role of behavioural flexibility at the individual level, adding new empirical evidence about how animals in general, and particularly scavengers, solve the problem of efficiently finding food resources. PMID:23372712

  12. Tests of a 3D visual-search model observer for SPECT

    NASA Astrophysics Data System (ADS)

    Gifford, Howard C.

    2013-03-01

    Observer studies with single 2D images can bias assessments of diagnostic technologies, as physicians usually have access to an entire image volume presented as multiple slices in multiple views. Previously, we introduced a scanning model observer for detection-localization tasks with multislice-multiview (or volumetric) display, but this observer did not compare well against human-observer data. The current work continues our investigation with tests of a 3D visual-search (VS) model observer. The VS framework amounts to an initial holistic search that identifies suspicious locations for analysis by a statistical observer. Our VS model uses a scanning observer for the analysis. The VS model was evaluated against the scanning and human observers in a localization ROC study of mass detection in SPECT lung imaging. The study compared two iterative reconstruction strategies that applied different combinations of corrections for attenuation, scatter, and distance-dependent system resolution. In our earlier work, the scanning and human observers ranked the strategies in opposite order of performance. The ranking from the VS observer matched that of the humans.

  13. Relationships among display features, eye movement characteristics, and reaction time in visual search.

    PubMed

    Murata, Atsuo; Furukawa, Nobuyasu

    2005-01-01

    The relative contribution of number of fixations and fixation duration to reaction time in visual search was investigated. Ten participants (age 20-24 years) took part in each of two experiments. In Experiment 1, the experimental factors were display type (icon and file name), organization (arrangements with and without grouping), and number of stimuli presented (4, 8, and 16). In Experiment 2, a search task for a target stimulus (three prespecified random letters) was conducted, and the experimental factor was the display's layout complexity. Multiple regression analysis was used to examine whether reaction time was explained by a mediational model in which reaction time is mediated by eye movements and display features are not directly related to reaction time. The mediational model was not supported, and the effects of display features on reaction time were not attributable solely to eye movements. The interaction between number of fixations and fixation duration was also explored as a function of display features. As the display feature changed and the task became more difficult, the contribution of the number of fixations to explain the variation in reaction time became dominant for both experiments. Potential applications include measurements of cognitive ability, eye muscle balance disorders, and binocular fusion ability. PMID:16435700

  14. Performance characteristics of a visual-search human-model observer with sparse PET image data

    NASA Astrophysics Data System (ADS)

    Gifford, Howard C.

    2012-02-01

    As predictors of human performance in detection-localization tasks, statistical model observers can have problems with tasks that are primarily limited by target contrast or structural noise. Model observers with a visual-search (VS) framework may provide a more reliable alternative. This framework provides for an initial holistic search that identifies suspicious locations for analysis by a statistical observer. A basic VS observer for emission tomography focuses on hot "blobs" in an image and uses a channelized nonprewhitening (CNPW) observer for analysis. In [1], we investigated this model for a contrast-limited task with SPECT images; herein, a statisticalnoise limited task involving PET images is considered. An LROC study used 2D image slices with liver, lung and soft-tissue tumors. Human and model observers read the images in coronal, sagittal and transverse display formats. The study thus measured the detectability of tumors in a given organ as a function of display format. The model observers were applied under several task variants that tested their response to structural noise both at the organ boundaries alone and over the organs as a whole. As measured by correlation with the human data, the VS observer outperformed the CNPW scanning observer.

  15. Visual search, movement behaviour and boat control during the windward mark rounding in sailing.

    PubMed

    Pluijms, Joost P; Cañal-Bruland, Rouwen; Hoozemans, Marco J M; Savelsbergh, Geert J P

    2015-01-01

    In search of key-performance predictors in sailing, we examined to what degree visual search, movement behaviour and boat control contribute to skilled performance while rounding the windward mark. To this end, we analysed 62 windward mark roundings sailed without opponents and 40 windward mark roundings sailed with opponents while competing in small regattas. Across conditions, results revealed that better performances were related to gazing more to the tangent point during the actual rounding. More specifically, in the condition without opponents, skilled performance was associated with gazing more outside the dinghy during the actual rounding, while in the condition with opponents, superior performance was related to gazing less outside the dinghy. With respect to movement behaviour, superior performance was associated with the release of the trimming lines close to rounding the mark. In addition, better performances were related to approaching the mark with little heel, yet heeling the boat more to the windward side when being close to the mark. Potential implications for practice are suggested for each phase of the windward mark rounding. PMID:25105956

  16. Investigation of Attentional Bias in Obsessive Compulsive Disorder with and without Depression in Visual Search

    PubMed Central

    Morein-Zamir, Sharon; Papmeyer, Martina; Durieux, Alice; Fineberg, Naomi A.; Sahakian, Barbara J.; Robbins, Trevor W.

    2013-01-01

    Whether Obsessive Compulsive Disorder (OCD) is associated with an increased attentional bias to emotive stimuli remains controversial. Additionally, it is unclear whether comorbid depression modulates abnormal emotional processing in OCD. This study examined attentional bias to OC-relevant scenes using a visual search task. Controls, non-depressed and depressed OCD patients searched for their personally selected positive images amongst their negative distractors, and vice versa. Whilst the OCD groups were slower than healthy individuals in rating the images, there were no group differences in the magnitude of negative bias to concern-related scenes. A second experiment employing a common set of images replicated the results on an additional sample of OCD patients. Although there was a larger bias to negative OC-related images without pre-exposure overall, no group differences in attentional bias were observed. However, OCD patients subsequently rated the images more slowly and more negatively, again suggesting post-attentional processing abnormalities. The results argue against a robust attentional bias in OCD patients, regardless of their depression status and speak to generalized difficulties disengaging from negative valence stimuli. Rather, post-attentional processing abnormalities may account for differences in emotional processing in OCD. PMID:24260343

  17. Using Geographic Information System to Visualize Travel Patterns and Market Research Data

    Microsoft Academic Search

    Charles Chancellor; Shu Cole

    2008-01-01

    Travel pattern data collected from a rural county in western North Carolina, United States, was analyzed using a geographic information system. Travel pattern data are valuable to destination marketers as it highlights potential regional promotions and development partners. Geographic information systems (GIS) can easily display in map form spatially oriented concepts such as travel patterns and provides easy viewing of

  18. Estimating the parameters of a model of visual search from ROC data: an alternate method for fitting proper ROC curves

    NASA Astrophysics Data System (ADS)

    Chakraborty, D. P.; Svahn, Tony

    2011-03-01

    The binormal receiver operating characteristic (ROC) model often predicts an unphysical "hook" near the upperright corner (1,1) of the ROC plot. Several models for fitting proper ROC curves avoid this problem. The purpose of this work is to describe another method that involves a model of visual search that models free-response data, and to compare the search-model predicted ROC curves with those predicted by PROPROC (proper ROC) software. The highest rating rule was used to infer ROC data from FROC data. An expression for the search-model ROC likelihood function is derived, maximizing which yielded estimates of the parameters and the fitted ROC curve. The method was applied to a dual-modality 5-reader FROC data set. The relative difference between the average AUCs for the two methods was less than 1%. A linear regression of the AUCs yielded an adjusted R-squared of 0.95 indicative of strong linear correlation between the search model AUC and PROPROC AUC, although the shapes of the predicted ROC curves were qualitatively different. This study shows the feasibility of estimating parameters characterizing visual search from data acquired in a non-search paradigm.

  19. More target features in visual working memory leads to poorer search guidance: Evidence from contralateral delay activity

    PubMed Central

    Schmidt, Joseph; MacNamara, Annmarie; Proudfit, Greg Hajcak; Zelinsky, Gregory J.

    2014-01-01

    The visual-search literature has assumed that the top-down target representation used to guide search resides in visual working memory (VWM). We directly tested this assumption using contralateral delay activity (CDA) to estimate the VWM load imposed by the target representation. In Experiment 1, observers previewed four photorealistic objects and were cued to remember the two objects appearing to the left or right of central fixation; Experiment 2 was identical except that observers previewed two photorealistic objects and were cued to remember one. CDA was measured during a delay following preview offset but before onset of a four-object search array. One of the targets was always present, and observers were asked to make an eye movement to it and press a button. We found lower magnitude CDA on trials when the initial search saccade was directed to the target (strong guidance) compared to when it was not (weak guidance). This difference also tended to be larger shortly before search-display onset and was largely unaffected by VWM item-capacity limits or number of previews. Moreover, the difference between mean strong- and weak-guidance CDA was proportional to the increase in search time between mean strong-and weak-guidance trials (as measured by time-to-target and reaction-time difference scores). Contrary to most search models, our data suggest that trials resulting in the maintenance of more target features results in poor search guidance to a target. We interpret these counterintuitive findings as evidence for strong search guidance using a small set of highly discriminative target features that remain after pruning from a larger set of features, with the load imposed on VWM varying with this feature-consolidation process. PMID:24599946

  20. The hard-won benefits of familiarity in visual search: naturally familiar brand logos are found faster.

    PubMed

    Qin, Xiaoyan Angela; Koutstaal, Wilma; Engel, Stephen A

    2014-05-01

    Familiar items are found faster than unfamiliar ones in visual search tasks. This effect has important implications for cognitive theory, because it may reveal how mental representations of commonly encountered items are changed by experience to optimize performance. It remains unknown, however, whether everyday items with moderate levels of exposure would show benefits in visual search, and if so, what kind of experience would be required to produce them. Here, we tested whether familiar product logos were searched for faster than unfamiliar ones, and also familiarized subjects with previously unfamiliar logos. Subjects searched for preexperimentally familiar and unfamiliar logos, half of which were familiarized in the laboratory, amongst other, unfamiliar distractor logos. In three experiments, we used an N-back-like familiarization task, and in four others we used a task that asked detailed questions about the perceptual aspects of the logos. The number of familiarization exposures ranged from 30 to 84 per logo across experiments, with two experiments involving across-day familiarization. Preexperimentally familiar target logos were searched for faster than were unfamiliar, nonfamiliarized logos, by 8 % on average. This difference was reliable in all seven experiments. However, familiarization had little or no effect on search speeds; its average effect was to improve search times by 0.7 %, and its effect was significant in only one of the seven experiments. If priming, mere exposure, episodic memory, or relatively modest familiarity were responsible for familiarity's effects on search, then performance should have improved following familiarization. Our results suggest that the search-related advantage of familiar logos does not develop easily or rapidly. PMID:24510424

  1. Search of Possible Triggered Seismicity Patterns of Northern Tien Shan

    NASA Astrophysics Data System (ADS)

    Novikov, V.; Vorontsova, E.

    2007-12-01

    Statistical analysis of the Northern Tien Shan seismicity was performed considering the possible triggering impacts of natural and man-made mechanical and electromagnetic factors on seismic activity. Strong distant earthquakes, lunar-solar tides, and magnetic storms are considered as natural triggering factors. The man-made factors include underground nuclear explosions (UNE) and electromagnetic impacts provided by high-power magnetohydrodynamic pulsed (MHD) generators. The representative local earthquake catalog of the region under study (41°-46° N, 74°-82° E) includes 15577 events of M>1.67 from 1975 to 2000. Within this time period 330 UNE and 109 firing runs of MHD generators, which are considered as the possible man-made earthquake triggering factors, have been performed within or adjacent to the analyzed region. Various statistical methods (cross-correlation, spectral analysis, RTL-analysis, etc.) were employed. For the used statement of problem and applied initial data the statistically significant patterns of triggered seismicity of the Northern Tien-Shan due to impacts of UNE and MHD generators were not found. Large common periods of seismicity variation for time series of distant strong earthquakes and local seismic events were selected. There is significant number of common periods (7, 9, 14, 28, 186, and 16384 days) for variation of z-component of the earth tide and release of seismic energy that may point to an influence of the earth tides on the local seismicity.

  2. Fast online and index-based algorithms for approximate search of RNA sequence-structure patterns

    PubMed Central

    2013-01-01

    Background It is well known that the search for homologous RNAs is more effective if both sequence and structure information is incorporated into the search. However, current tools for searching with RNA sequence-structure patterns cannot fully handle mutations occurring on both these levels or are simply not fast enough for searching large sequence databases because of the high computational costs of the underlying sequence-structure alignment problem. Results We present new fast index-based and online algorithms for approximate matching of RNA sequence-structure patterns supporting a full set of edit operations on single bases and base pairs. Our methods efficiently compute semi-global alignments of structural RNA patterns and substrings of the target sequence whose costs satisfy a user-defined sequence-structure edit distance threshold. For this purpose, we introduce a new computing scheme to optimally reuse the entries of the required dynamic programming matrices for all substrings and combine it with a technique for avoiding the alignment computation of non-matching substrings. Our new index-based methods exploit suffix arrays preprocessed from the target database and achieve running times that are sublinear in the size of the searched sequences. To support the description of RNA molecules that fold into complex secondary structures with multiple ordered sequence-structure patterns, we use fast algorithms for the local or global chaining of approximate sequence-structure pattern matches. The chaining step removes spurious matches from the set of intermediate results, in particular of patterns with little specificity. In benchmark experiments on the Rfam database, our improved online algorithm is faster than the best previous method by up to factor 45. Our best new index-based algorithm achieves a speedup of factor 560. Conclusions The presented methods achieve considerable speedups compared to the best previous method. This, together with the expected sublinear running time of the presented index-based algorithms, allows for the first time approximate matching of RNA sequence-structure patterns in large sequence databases. Beyond the algorithmic contributions, we provide with RaligNAtor a robust and well documented open-source software package implementing the algorithms presented in this manuscript. The RaligNAtor software is available at http://www.zbh.uni-hamburg.de/ralignator. PMID:23865810

  3. Systematic search for successful lepton mixing patterns with nonzero theta_13

    E-print Network

    Werner Rodejohann; He Zhang; Shun Zhou

    2011-10-28

    We perform a systematic search for simple but viable lepton mixing patterns. Our main criterion is that the mixing matrix can be parameterized by three rotation angles, which are simple fractions of pi. These simple rotation angles possess exact expressions for their sines and cosines, and often arise in the flavor symmetry models. All possible parameterizations of the mixing matrix are taken into account. In total, twenty successful mixing patterns are found to be consistent with the latest neutrino oscillation data (including the recent T2K results) in the CP conserving case, whereas fifteen mixing patterns are allowed in the maximal CP violating case. Potential radiative corrections to the constant mixing patterns are also calculated by solving the renormalization group equations.

  4. Interactive Visualization and Navigation of Web Search Results Revealing Community Structures and Bridges

    E-print Network

    Paris-Sud XI, Université de

    are presented based on searching different topics on Wikipedia through Exalead's search engine. Keywords of a query launched on a search engine [28]. Search engines such as Google, tend to return a long list [4]. Consider searching for the word Jaguar using Google Search Engine. Looking at the top seven

  5. The Validity of the Cosmic String Pattern Search with the Cosmic Microwave Background

    E-print Network

    E. Jeong; G. F. Smoot

    2007-05-11

    We introduce a new technique to detect the discrete temperature steps that cosmic strings might have left in the cosmic microwave background (CMB) anisotropy map. The technique provides a validity test on the pattern search of cosmic strings that could serve as the groundwork for future pattern searches. The detecting power of the technique is only constrained by two unavoidable features of CMB data: (1) the finite pixelization of the sky map and (2) the Gaussian fluctuation from instrumental noise and primordial anisotropy. We set the upper limit on the cosmic string parameter as $G\\mu\\lesssim 3.7\\times 10^{-6}$ at the 95% confidence level (CL) and find that the amplitude of the temperature step has to be greater than $44\\mu K$ in order to be detected for the {\\it{Wilkinson Microwave Anisotropy Probe (WMAP)}} 3 year data.

  6. Hybrid General Pattern Search and Simulated Annealing for Industrail Production Planning Problems

    NASA Astrophysics Data System (ADS)

    Vasant, P.; Barsoum, N.

    2010-06-01

    In this paper, the hybridization of GPS (General Pattern Search) method and SA (Simulated Annealing) incorporated in the optimization process in order to look for the global optimal solution for the fitness function and decision variables as well as minimum computational CPU time. The real strength of SA approach been tested in this case study problem of industrial production planning. This is due to the great advantage of SA for being easily escaping from trapped in local minima by accepting up-hill move through a probabilistic procedure in the final stages of optimization process. Vasant [1] in his Ph. D thesis has provided 16 different techniques of heuristic and meta-heuristic in solving industrial production problems with non-linear cubic objective functions, eight decision variables and 29 constraints. In this paper, fuzzy technological problems have been solved using hybrid techniques of general pattern search and simulated annealing. The simulated and computational results are compared to other various evolutionary techniques.

  7. Properties of V1 Neurons Tuned to Conjunctions of Visual Features: Application of the V1 Saliency Hypothesis to Visual Search behavior

    PubMed Central

    Zhaoping, Li; Zhe, Li

    2012-01-01

    From a computational theory of V1, we formulate an optimization problem to investigate neural properties in the primary visual cortex (V1) from human reaction times (RTs) in visual search. The theory is the V1 saliency hypothesis that the bottom-up saliency of any visual location is represented by the highest V1 response to it relative to the background responses. The neural properties probed are those associated with the less known V1 neurons tuned simultaneously or conjunctively in two feature dimensions. The visual search is to find a target bar unique in color (C), orientation (O), motion direction (M), or redundantly in combinations of these features (e.g., CO, MO, or CM) among uniform background bars. A feature singleton target is salient because its evoked V1 response largely escapes the iso-feature suppression on responses to the background bars. The responses of the conjunctively tuned cells are manifested in the shortening of the RT for a redundant feature target (e.g., a CO target) from that predicted by a race between the RTs for the two corresponding single feature targets (e.g., C and O targets). Our investigation enables the following testable predictions. Contextual suppression on the response of a CO-tuned or MO-tuned conjunctive cell is weaker when the contextual inputs differ from the direct inputs in both feature dimensions, rather than just one. Additionally, CO-tuned cells and MO-tuned cells are often more active than the single feature tuned cells in response to the redundant feature targets, and this occurs more frequently for the MO-tuned cells such that the MO-tuned cells are no less likely than either the M-tuned or O-tuned neurons to be the most responsive neuron to dictate saliency for an MO target. PMID:22719829

  8. Influence of Satiety and Subjective Valence Rating on Cerebral Activation Patterns in Response to Visual Stimulation with High-Calorie Stimuli among Restrictive Anorectic and Control Women

    Microsoft Academic Search

    Elke R. Gizewski; Christina Rosenberger; Armin de Greiff; Andrea Moll; Wolfgang Senf; Isabel Wanke; Michael Forsting; Stephan Herpertz

    2010-01-01

    Background: There is evidence that patients with anorexia nervosa (AN) demonstrate specific cerebral activation patterns in response to visual food stimulation. We postulated that cerebral activation patterns could represent different perceptions of high-calorie images during hunger and satiety and could be determined by patients’ subjective ratings. Methods: After 6 h of starvation and also in a state of satiety, 12

  9. Exhaustive Generation and Visual Browsing for Radiation Patterns of Linear Array Antennas

    Microsoft Academic Search

    Darren Leigh; Tom Lanning; Neal Lesh; Kathy Ryall

    2004-01-01

    Almost any obtainable radiation pattern can be achieved with a phased array antenna if the phases and amplitudes are chosen correctly. However, if these are quantized, it can be a time consuming and difficult process for a human expert to determine the best Quantized excitation coefficients to produce a desired radiation pattern. In this paper, we explore the use of

  10. Changing Patterns of Expression and Subcellular Localization of TrkB in the Developing Visual System

    Microsoft Academic Search

    Robert J. Cabelli; Karen L. Allendoerfer; Monte J. Radeke; Andrew A. Welcher; Stuart C. Feinstein; Carla J. Shatz

    1996-01-01

    Neurotrophins play important roles in the survival, differentia- tion, and maintenance of CNS neurons. To begin to investigate specific roles for these factors in the mammalian visual system, we have examined the cellular localization of the neurotrophin receptor trkB within the developing cerebral cortex and thala- mus of the ferret using extracellular domain-specific antibodies. At prenatal ages (gestation is 41

  11. Flow visualization studies of transverse fuel injection patterns in a nonreacting Mach 2 combustor

    NASA Technical Reports Server (NTRS)

    Mcdaniel, J. C.

    1987-01-01

    Planar visualization images are recorded of transverse jet mixing in a supersonic combustor flowfield, without chemical reaction, using laser-induced fluorescence from iodine molecules. Digital image processing and three-dimensional display enable complete representations of fuel penetration boundary and shock surfaces corresponding to several injection geometries and pressures.

  12. Gene expression patterns in visual cortex during the critical period: Synaptic stabilization and reversal

    E-print Network

    Sur, Mriganka

    between the two eyes during a restricted postnatal critical period for ocular dominance plasticity parts of visual cortical processing areas. The left-eye versus right-eye responsiveness, or ocular eye and a regression of that of the closed eye. Ocular dominance plasticity depends on coincidence

  13. Experimental analysis and visualization of spatiotemporal patterns in spouted fluidized beds

    Microsoft Academic Search

    Antonio Palacios; Charles Finney; Paul Cizmas; Stuart Daw; Thomas O'Brien

    2004-01-01

    A numerical characterization based on experimental data of the spouting regime in a two-dimensional fluidized bed is presented. The aspect ratio of the bed allowed for good visualization of the spouting and solids circulation as the spouting jet gas velocity was varied to highlight the visited bifurcation sequence. Digital video sequences were recorded and then preprocessed for numerical analysis. In

  14. Visualizing Interaction Patterns in Online Discussions and Indices of Cognitive Presence

    ERIC Educational Resources Information Center

    Gibbs, William J.

    2006-01-01

    This paper discusses Mapping Temporal Relations of Discussions Software (MTRDS), a Web-based application that visually represents the temporal relations of online discussions. MTRDS was used to observe interaction characteristics of three online discussions. In addition, the research employed the Practical Inquiry Model to identify indices of…

  15. Directional responses of visual wulst neurones to grating and plaid patterns in the awake owl.

    PubMed

    Baron, Jerome; Pinto, Lucas; Dias, Marcelo Oliveira; Lima, Bruss; Neuenschwander, Sergio

    2007-10-01

    The avian retinothalamofugal pathway reaches the telencephalon in an area known as visual wulst. A close functional analogy between this area and the early visual cortex of mammals has been established in owls. The goal of the present study was to assess quantitatively the directional selectivity and motion integration capability of visual wulst neurones, aspects that have not been previously investigated. We recorded extracellularly from a total of 101 cells in awake burrowing owls. From this sample, 88% of the units exhibited modulated directional responses to sinusoidal gratings, with a mean direction index of 0.74 +/- 0.03 and tuning bandwidth of 28 +/- 1.16 degrees . A direction index higher than 0.5 was observed in 66% of the cells, thereby qualifying them as direction selective. Motion integration was tested with moving plaids, made by adding two sinusoidal gratings of different orientations. We found that 80% of direction-selective cells responded optimally to the motion direction of the component gratings, whereas none responded to the global motion of plaids, whose direction was intermediate to that of the gratings. The remaining 20% were unclassifiable. The strength of component motion selectivity rapidly increased over a 200 ms period following stimulus onset, maintaining a relatively sustained profile thereafter. Overall, our data suggest that, as in the mammalian primary visual cortex, the visual wulst neurones of owls signal the local orientated features of a moving object. How and where these potentially ambiguous signals are integrated in the owl brain might be important for understanding the mechanisms underlying global motion perception. PMID:17897399

  16. Heuristic Search and Information Visualization Methods for School Redistricting Marie desJardins, Blazej Bulka, Ryan Carr, Eric Jordan, and Penny Rheingans

    E-print Network

    Rheingans, Penny

    Heuristic Search and Information Visualization Methods for School Redistricting Marie des- alization techniques to the problem of school redistricting, in which students are assigned to home schools in finding multiple qual- itatively different redistricting plans that represent different tradeoffs

  17. Perceptual Factors Influence Visual Search for Meaningful Symbols In Individuals with Intellectual Disabilities and Down Syndrome or Autism Spectrum Disorders

    PubMed Central

    Wilkinson, Krista M.; McIlvane, William J.

    2013-01-01

    Augmentative and alternative communication (AAC) systems often supplement oral communication of individuals with intellectual and communication disabilities. Research with nondisabled preschoolers has demonstrated that two visual perceptual factors influence speed and/or accuracy of finding a target - the internal color and spatial organization of symbols. Twelve participants with Down syndrome and 12 with ASD underwent two search tasks. In one, the symbols were clustered by internal color; in the other the identical symbols had no arrangement cue. Visual search was superior in participants with ASD compared to those with Down syndrome. In both groups, responses were significantly faster when the symbols were clustered by internal color. Construction of aided AAC displays may benefit from attention to their physical/perceptual features. PMID:24245729

  18. Changes in pattern-evoked responses in man associated with the vertical and horizontal meridians of the visual field

    PubMed Central

    Halliday, A. M.; Michael, W. F.

    1970-01-01

    1. Averaged responses have been recorded from an array of ten scalp electrodes over the occipital cortex in man to the reversal of a black-and-white checkerboard pattern, presented in different octants of the visual field. 2. In all subjects a prominent wave was seen, with a peak latency of about 100 msec, which showed consistent and systematic changes with variation in the position of the stimulus in the visual field. 3. With stimulation of the octants next to the vertical meridian, this component was of large amplitude, while with stimulation of the octants next to the horizontal meridian, it was small and inconspicuous. 4. With upper field octants, the peak at 100 msec was surface-negative, while with lower field octants it was reversed in polarity. 5. The occipital response was largest 5 or 7·5 cm above the inion, and the amplitude recorded 3 cm lateral to the mid line was larger over the hemisphere contralateral to the half field being stimulated than ipsilaterally. 6. These findings are discussed in relation to the underlying anatomy of the visual cortex, and it is concluded that these responses are likely to arise mainly from extra-striate areas. PMID:5533451

  19. Functionality pattern matching as an efficient complementary structure/reaction search tool: an open-source approach.

    PubMed

    Haider, Norbert

    2010-08-01

    An open-source software package for creating and operating web-based structure and/or reaction databases is presented. Besides standard search capabilities (text, structure/substructure/similarity), the system offers a fast additional search option, entirely based on binary pattern matching, which uses automatically assigned functional group descriptors. PMID:20714286

  20. Assessment of prostate cancer detection with a visual-search human model observer

    NASA Astrophysics Data System (ADS)

    Sen, Anando; Kalantari, Faraz; Gifford, Howard C.

    2014-03-01

    Early staging of prostate cancer (PC) is a significant challenge, in part because of the small tumor sizes in- volved. Our long-term goal is to determine realistic diagnostic task performance benchmarks for standard PC imaging with single photon emission computed tomography (SPECT). This paper reports on a localization receiver operator characteristic (LROC) validation study comparing human and model observers. The study made use of a digital anthropomorphic phantom and one-cm tumors within the prostate and pelvic lymph nodes. Uptake values were consistent with data obtained from clinical In-111 ProstaScint scans. The SPECT simulation modeled a parallel-hole imaging geometry with medium-energy collimators. Nonuniform attenua- tion and distance-dependent detector response were accounted for both in the imaging and the ordered-subset expectation-maximization (OSEM) iterative reconstruction. The observer study made use of 2D slices extracted from reconstructed volumes. All observers were informed about the prostate and nodal locations in an image. Iteration number and the level of postreconstruction smoothing were study parameters. The results show that a visual-search (VS) model observer correlates better with the average detection performance of human observers than does a scanning channelized nonprewhitening (CNPW) model observer.

  1. Visual Pattern Memory Requires "Foraging" Function in the Central Complex of "Drosophila"

    ERIC Educational Resources Information Center

    Wang, Zhipeng; Pan, Yufeng; Li, Weizhe; Jiang, Huoqing; Chatzimanolis, Lazaros; Chang, Jianhong; Gong, Zhefeng; Liu, Li

    2008-01-01

    The role of the "foraging" ("for)" gene, which encodes a cyclic guanosine-3',5'-monophosphate (cGMP)-dependent protein kinase (PKG), in food-search behavior in "Drosophila" has been intensively studied. However, its functions in other complex behaviors have not been well-characterized. Here, we show experimentally in "Drosophila" that the "for"…

  2. Plate Scattering Visualization: Images, Near Fields, Currents, and Far Field Patterns

    NASA Technical Reports Server (NTRS)

    Shaeffer, John; Hom, Kam

    2004-01-01

    This paper presents a case study of a simple yet robust target for demonstration of the EM visualization process. A five lambda square plate exhibits many scattering mechanisms depending on excitation angle and polarization: specular scattering, leading and trailing edge diffraction, traveling wave, and edge wave scattering. Bistatic k space radiation images, currents maps, and near scattered / total fields are examined for each of these scattering mechanisms.

  3. Visualization of significant ERD\\/ERS patterns in multichannel EEG and ECoG data

    Microsoft Academic Search

    B Graimann; J. E Huggins; S. P Levine; G Pfurtscheller

    2002-01-01

    Objectives: Analysis of event-related desynchronization (ERD) and event-related synchronization (ERS) often requires the investigation of diverse frequency bands. Such analysis can be difficult, especially when using multichannel data. Therefore, an effective method for the visualization of event-related changes in oscillatory brain activity is required.Methods: A bootstrap-based method is presented which gives time–frequency maps showing only significant changes of ERD or

  4. Optimal Refueling Pattern Search for a CANDU Reactor Using a Genetic Algorithm

    SciTech Connect

    Quang Binh, DO; Gyuhong, ROH; Hangbok, CHOI [Korea Atomic Energy Research Institute, Dukjindong 150, Yusong, Daejeon, 305-353 (Korea, Republic of)

    2006-07-01

    This paper presents the results from the application of genetic algorithms to a refueling optimization of a Canada deuterium uranium (CANDU) reactor. This work aims at making a mathematical model of the refueling optimization problem including the objective function and constraints and developing a method based on genetic algorithms to solve the problem. The model of the optimization problem and the proposed method comply with the key features of the refueling strategy of the CANDU reactor which adopts an on-power refueling operation. In this study, a genetic algorithm combined with an elitism strategy was used to automatically search for the refueling patterns. The objective of the optimization was to maximize the discharge burn-up of the refueling bundles, minimize the maximum channel power, or minimize the maximum change in the zone controller unit (ZCU) water levels. A combination of these objectives was also investigated. The constraints include the discharge burn-up, maximum channel power, maximum bundle power, channel power peaking factor and the ZCU water level. A refueling pattern that represents the refueling rate and channels was coded by a one-dimensional binary chromosome, which is a string of binary numbers 0 and 1. A computer program was developed in FORTRAN 90 running on an HP 9000 workstation to conduct the search for the optimal refueling patterns for a CANDU reactor at the equilibrium state. The results showed that it was possible to apply genetic algorithms to automatically search for the refueling channels of the CANDU reactor. The optimal refueling patterns were compared with the solutions obtained from the AUTOREFUEL program and the results were consistent with each other. (authors)

  5. Orientation preference patterns in mammalian visual cortex: a wire length minimization approach.

    PubMed

    Koulakov, A A; Chklovskii, D B

    2001-02-01

    In the visual cortex of many mammals, orientation preference changes smoothly along the cortical surface, with the exception of singularities such as pinwheels and fractures. The reason for the existence of these singularities has remained elusive, suggesting that they are developmental artifacts. We show that singularities reduce the length of intracortical neuronal connections for some connection rules. Therefore, pinwheels and fractures could be evolutionary adaptations keeping cortical volume to a minimum. Wire length minimization approach suggests that interspecies differences in orientation preference maps reflect differences in intracortical neuronal circuits, thus leading to experimentally testable predictions. We discuss application of our model to direction preference maps. PMID:11239440

  6. Peripheral Vision of Youths with Low Vision: Motion Perception, Crowding, and Visual Search

    E-print Network

    Tadin, Duje

    Low Vision Peripheral Vision of Youths with Low Vision: Motion Perception, Crowding, and Visual. Effects of low vision on peripheral visual function are poorly understood, especially in children whose visual functions in youths with typical and low vision. Of specific interest was the extent to which

  7. Gender differences in pedestrian rule compliance and visual search at signalized and unsignalized crossroads.

    PubMed

    Tom, Ariane; Granié, Marie-Axelle

    2011-09-01

    Male pedestrians are over-represented in road crashes. Among pedestrians, males violate more rules than females do. For now, it is not known whether gender differences in pedestrian behaviors only concern rule compliance. The objective of this study was to explore gender differences in pedestrian rule compliance and in gaze targets before and during crossing. 400 adult pedestrians were observed at two signalized and two unsignalized crossroads, using a taxonomic observation grid which detailed 13 behavioral categories before, during and after crossing. The results show that the temporal crossing compliance rate is lower among male pedestrians but spatial crossing compliance does not differ between genders. Furthermore, different gaze patterns emerge between genders before and during crossing, notably as women particularly focus on other pedestrians during these two periods whereas men focus on vehicles. Moreover, females' gazes vary with the type of crossroads, but males' gazes do not. Spatial crossing compliance and gaze targets are furthermore modulated by the crossroad configuration. These results are discussed in terms of pedestrian visual strategy and compliance. PMID:21658507

  8. Universal Information Graphs Many pattern detection applications require analysis and visualization of massive

    E-print Network

    marries notions from relational databases to notions from graph theory in order to develop new record database, and we have implemented a method that is able to process a semantic dot product graph with upUniversal Information Graphs Mission Many pattern detection applications require analysis

  9. Analyzing and geo-visualizing individual human mobility patterns using mobile call records

    Microsoft Academic Search

    Chaogui Kang; Song Gao; Xing Lin; Yu Xiao; Yihong Yuan; Yu Liu; Xiujun Ma

    2010-01-01

    Understanding the dynamics of the individuals' daily mobility patterns is very important in a wide range of fields. However, lacking of tools to monitor the time-resolved location of individuals makes this research consume both tremendous time and money in the past. Nowadays, the rapidly developing ability to collect space-time activity (STA) data through new information technologies such as cellular phones,

  10. Elementary Visual Hallucinations and Their Relationships to Neural Pattern-Forming Mechanisms

    ERIC Educational Resources Information Center

    Billock, Vincent A.; Tsou, Brian H.

    2012-01-01

    An extraordinary variety of experimental (e.g., flicker, magnetic fields) and clinical (epilepsy, migraine) conditions give rise to a surprisingly common set of elementary hallucinations, including spots, geometric patterns, and jagged lines, some of which also have color, depth, motion, and texture. Many of these simple hallucinations fall into a…

  11. Visual pattern-discrimination in the vertebrates - I. Problem and methods

    Microsoft Academic Search

    H. M. Johnson

    1914-01-01

    Investigated the factor of vision in sexual selection, in terms of pattern-discrimination. Four problems were studied: (1) stimulus threshold for striation (2) difference threshold for size of visible striation (3) difference threshold for direction of visible striation; and (4) brightness-discrimination. The apparatus for the first 3 problems consisted in an instrument for presenting opaque lines ruled on glass. For the

  12. How Bumblebees First Find Flowers: Habituation of Visual Pattern Preferences, Spontaneous Recovery, and Dishabituation

    ERIC Educational Resources Information Center

    Plowright, C. M. S.; Simonds, V. M.; Butler, M. A.

    2006-01-01

    Two experiments examined the exploratory behaviour of flower-naive bumblebees. Bees were tested four times in a 12-arm radial arm maze in which they never received reward. Patterned and unpatterned stimuli were presented at the end of each corridor and the choices of the bees were recorded. We examined the effects of two variables, time and the…

  13. The influence of spatial pattern on visual short-term memory for contrast.

    PubMed

    Xing, Yue; Ledgeway, Tim; McGraw, Paul; Schluppeck, Denis

    2014-10-01

    Several psychophysical studies of visual short-term memory (VSTM) have shown high-fidelity storage capacity for many properties of visual stimuli. On judgments of the spatial frequency of gratings, for example, discrimination performance does not decrease significantly, even for memory intervals of up to 30 s. For other properties, such as stimulus orientation and contrast, however, such "perfect storage" behavior is not found, although the reasons for this difference remain unresolved. Here, we report two experiments in which we investigated the nature of the representation of stimulus contrast in VSTM using spatially complex, two-dimensional random-noise stimuli. We addressed whether information about contrast per se is retained during the memory interval by using a test stimulus with the same spatial structure but either the same or the opposite local contrast polarity, with respect to the comparison (i.e., remembered) stimulus. We found that discrimination thresholds got steadily worse with increasing duration of the memory interval. Furthermore, performance was better when the test and comparison stimuli had the same local contrast polarity than when they were contrast-reversed. Finally, when a noise mask was introduced during the memory interval, its disruptive effect was maximal when the spatial configuration of its constituent elements was uncorrelated with those of the comparison and test stimuli. These results suggest that VSTM for contrast is closely tied to the spatial configuration of stimuli and is not transformed into a more abstract representation. PMID:24715467

  14. APPSPACK 4.0 : asynchronous parallel pattern search for derivative-free optimization.

    SciTech Connect

    Gray, Genetha Anne; Kolda, Tamara Gibson

    2004-12-01

    APPSPACK is software for solving unconstrained and bound constrained optimization problems. It implements an asynchronous parallel pattern search method that has been specifically designed for problems characterized by expensive function evaluations. Using APPSPACK to solve optimization problems has several advantages: No derivative information is needed; the procedure for evaluating the objective function can be executed via a separate program or script; the code can be run in serial or parallel, regardless of whether or not the function evaluation itself is parallel; and the software is freely available. We describe the underlying algorithm, data structures, and features of APPSPACK version 4.0 as well as how to use and customize the software.

  15. A Performance Analysis of Evolutionary Pattern Search with Generalized Mutation Steps

    SciTech Connect

    Hart, W.; Hunter, K.

    1999-02-10

    Evolutionary pattern search algorithms (EPSAs) are a class of evolutionary algorithms (EAs) that have convergence guarantees on a broad class of nonconvex continuous problems. In previous work we have analyzed the empirical performance of EPSAs. This paper revisits that analysis and extends it to a more general model of mutation. We experimentally evaluate how the choice of the set of mutation offsets affects optimization performance for EPSAs. Additionally, we compare EPSAs to self-adaptive EAs with respect to robustness and rate of optimization. All experiments employ a suite of test functions representing a range of modality and number of multiple minima.

  16. Application of holography to flow visualization within rotating compressor blade row. [to determine three dimensional shock patterns

    NASA Technical Reports Server (NTRS)

    Wuerker, R. F.; Kobayashi, R. J.; Heflinger, L. O.; Ware, T. C.

    1974-01-01

    Two holographic interblade row flow visualization systems were designed to determine the three-dimensional shock patterns and velocity distributions within the rotating blade row of a transonic fan rotor, utilizing the techniques of pulsed laser transmission holography. Both single- and double-exposure bright field holograms and dark field scattered-light holograms were successfully recorded. Two plastic windows were installed in the rotor tip casing and outer casing forward of the rotor to view the rotor blade passage. The viewing angle allowed detailed investigation of the leading edge shocks and shocks in the midspan damper area; limited details of the trailing edge shocks also were visible. A technique was devised for interpreting the reconstructed holograms by constructing three dimensional models that allowed identification of the major shock systems. The models compared favorably with theoretical predictions and results of the overall and blade element data. Most of the holograms were made using the rapid double-pulse technique.

  17. Intrinsic motivation and attentional capture from gamelike features in a visual search task.

    PubMed

    Miranda, Andrew T; Palmer, Evan M

    2014-03-01

    In psychology research studies, the goals of the experimenter and the goals of the participants often do not align. Researchers are interested in having participants who take the experimental task seriously, whereas participants are interested in earning their incentive (e.g., money or course credit) as quickly as possible. Creating experimental methods that are pleasant for participants and that reward them for effortful and accurate data generation, while not compromising the scientific integrity of the experiment, would benefit both experimenters and participants alike. Here, we explored a gamelike system of points and sound effects that rewarded participants for fast and accurate responses. We measured participant engagement at both cognitive and perceptual levels and found that the point system (which invoked subtle, anonymous social competition between participants) led to positive intrinsic motivation, while the sound effects (which were pleasant and arousing) led to attentional capture for rewarded colors. In a visual search task, points were awarded after each trial for fast and accurate responses, accompanied by short, pleasant sound effects. We adapted a paradigm from Anderson, Laurent, and Yantis (Proceedings of the National Academy of Sciences 108(25):10367-10371, 2011b), in which participants completed a training phase during which red and green targets were probabilistically associated with reward (a point bonus multiplier). During a test phase, no points or sounds were delivered, color was irrelevant to the task, and previously rewarded targets were sometimes presented as distractors. Significantly longer response times on trials in which previously rewarded colors were present demonstrated attentional capture, and positive responses to a five-question intrinsic-motivation scale demonstrated participant engagement. PMID:23835649

  18. Cube search, revisited.

    PubMed

    Zhang, Xuetao; Huang, Jie; Yigit-Elliott, Serap; Rosenholtz, Ruth

    2015-01-01

    Observers can quickly search among shaded cubes for one lit from a unique direction. However, replace the cubes with similar 2-D patterns that do not appear to have a 3-D shape, and search difficulty increases. These results have challenged models of visual search and attention. We demonstrate that cube search displays differ from those with "equivalent" 2-D search items in terms of the informativeness of fairly low-level image statistics. This informativeness predicts peripheral discriminability of target-present from target-absent patches, which in turn predicts visual search performance, across a wide range of conditions. Comparing model performance on a number of classic search tasks, cube search does not appear unexpectedly easy. Easy cube search, per se, does not provide evidence for preattentive computation of 3-D scene properties. However, search asymmetries derived from rotating and/or flipping the cube search displays cannot be explained by the information in our current set of image statistics. This may merely suggest a need to modify the model's set of 2-D image statistics. Alternatively, it may be difficult cube search that provides evidence for preattentive computation of 3-D scene properties. By attributing 2-D luminance variations to a shaded 3-D shape, 3-D scene understanding may slow search for 2-D features of the target. PMID:25780063

  19. Cube search, revisited

    PubMed Central

    Zhang, Xuetao; Huang, Jie; Yigit-Elliott, Serap; Rosenholtz, Ruth

    2015-01-01

    Observers can quickly search among shaded cubes for one lit from a unique direction. However, replace the cubes with similar 2-D patterns that do not appear to have a 3-D shape, and search difficulty increases. These results have challenged models of visual search and attention. We demonstrate that cube search displays differ from those with “equivalent” 2-D search items in terms of the informativeness of fairly low-level image statistics. This informativeness predicts peripheral discriminability of target-present from target-absent patches, which in turn predicts visual search performance, across a wide range of conditions. Comparing model performance on a number of classic search tasks, cube search does not appear unexpectedly easy. Easy cube search, per se, does not provide evidence for preattentive computation of 3-D scene properties. However, search asymmetries derived from rotating and/or flipping the cube search displays cannot be explained by the information in our current set of image statistics. This may merely suggest a need to modify the model's set of 2-D image statistics. Alternatively, it may be difficult cube search that provides evidence for preattentive computation of 3-D scene properties. By attributing 2-D luminance variations to a shaded 3-D shape, 3-D scene understanding may slow search for 2-D features of the target. PMID:25780063

  20. Temporal encoding of two-dimensional patterns by single units in primate primary visual cortex. I. Stimulus-response relations.

    PubMed

    Richmond, B J; Optican, L M; Spitzer, H

    1990-08-01

    1. Previously we developed a new approach for investigating visual system neuronal activity in which single neurons are considered to be communication channels transmitting stimulus-dependent codes in their responses. Application of this approach to the stimulus-response relations of inferior temporal (IT) neurons showed that these carry stimulus-dependent information in the temporal modulation as well as in the strength of their responses. IT cortex is a late station in the visual processing stream. Presumably the neuronal properties arise from the properties of the inputs. However, the discovery that IT neuronal spike trains transmit information in stimulus-dependent temporally modulated codes could not be assumed to be true for those earlier stations, so the techniques used in the earlier study were applied to single-striate cortical neurons in the studies reported here. 2. Single-striate cortical neurons were recorded from three awake, fixating rhesus monkeys. The neurons were stimulated by two sets of patterns. The first set was made up of 128 black-and-white patterns based on a complete, orthogonal set of two-dimensional Walsh-Hadamard functions. These stimuli appear as combinations of black-and-white rectangles and squares, and they fully span the range of all possible black-and-white pictures that can be constructed in an 8 x 8 grid. Except for the stimulus that appeared as an all-white or all-black square, each stimulus had equal areas of white and black. The second stimulus set was made up of single bars constructed in the same 8 x 8 grid as the Walsh stimuli. These were presented both as black against a gray background and white against a gray background. The stimuli were centered on the receptive field, and each member of the stimulus set was presented once before any stimulus appeared again. 3. The responses of 21 striate cortical neurons were recorded and analyzed. Two were identified as simple cells and the other 19 as complex cells according to the criteria originally used by Hubel and Wiesel. The stimulus set elicited a wide variety of response strengths and patterns from each neuron. The responses from both the bars and the Walsh set could be used to differentiate and classify simple and complex cells. 4. The responses of both simple and complex cells showed striking stimulus-related strength and temporal modulation. For all of the complex cells there were instances where the responses to a stimulus and its contrast-reversed mate were substantially different in response strength or pattern, or both.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2213122