1,721,906 research outputs found
Grouping effects on spatial attention in visual search.
No full textIn visual search tasks, spatial attention selects the locations containing a target or a distractor with one of the target's features, implying that spatial attention is driven by target features (M.-S. Kim & K. R. Cave, 1995). The authors measured the effects of location-based grouping processes in visual search. In searches for a color-shape combination (conjunction search), spatial probes indicated that a cluster of same-color or same-shape elements surrounding the target were grouped and selected together. However, in searches for a shape target (feature search), evidence for grouping by an irrelevant feature dimension was weaker or nonexistent. Grouping processes aided search for a visual target by selecting groups of locations that shared a common feature, although there was little or no grouping by an irrelevant feature when the target was defined by a unique salient feature
Microfluidic 3-Dimensional Encapsulation System by Self-Assembling Peptide Hydrogel
No full textThis article describes a novel microfluidic 3-dimensional encapsulation method via the self-assembling peptide hydrogel. The microfluidic immobilization strategies using a peptide hydrogel have been designed for microfluidic cell-based assays, cocultures, and biomimetic micro blood vessels. A sol-gel transition peptide hydrogel, Puramatrix, is adopted for use in the microfluidic device fabricated by photolithography and a poly(dimethylsiloxane) replica molding process. The peptide hydrogel was hydrodynamically focused by sheath flows of distilled water and cell culture media, and gelled by diffusion of media. After being transitioned from a sol to gel phase, the fabricated scaffold in the middle of the main channel was not washed away via fluid flows. The diffused chemicals in a stripe-shaped peptide scaffold of microchannel formed a linear concentration gradient within the scaffold. Based on application in an in vivo-like 3-dimensional microenvironment, this microfluidic system could be applied to cocultures, angiological research, cytotoxicity tests, cell viability monitoring, and continuous dose-response assays as well as drug-drug interaction studies. ？ 2006 The Association for Laboratory Automation
In-vitro experimental results of real time visual servoing for the laparoscope manipulator
No full textDevelopment of a Combined Optical and X-ray Interferometer (COXI) system for nanometrology
No full textTop-down and Bottom-up Attentional Control: On the Nature of Interference from a Salient Distractor
No full textIn two experiments using spatial probes, we measured the temporal and spatial interactions between top-down control of attention and bottom-up interference from a salient distractor in visual search. The subjects searched for a square among circles, ignoring color. Probe response times showed that a color singleton distractor could draw attention to its location in the early stage of visual processing (before a 100-msec stimulus onset asynchrony [SOA]), but only when the color singleton distractor was located far from the target. Apparently the bottom-up activation of the singleton distractor's location is affected early on by local interactions with nearby stimulus locations. Moreover, probe results showed that a singleton distractor did not receive attention after extended practice. These results suggest that top-down control of attention is possible at an early stage of visual processing. In the long-SOA condition (150-msec SOA), spatial attention selected the target location over distractor locations, and this tendency occurred with or without extended practice.<br/
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