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Search Results: 1 - 10 of 23380 matches for " Zhuanghua Shi "
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Motion Extrapolation in the Central Fovea
Zhuanghua Shi, Romi Nijhawan
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0033651
Abstract: Neural transmission latency would introduce a spatial lag when an object moves across the visual field, if the latency was not compensated. A visual predictive mechanism has been proposed, which overcomes such spatial lag by extrapolating the position of the moving object forward. However, a forward position shift is often absent if the object abruptly stops moving (motion-termination). A recent “correction-for-extrapolation” hypothesis suggests that the absence of forward shifts is caused by sensory signals representing ‘failed’ predictions. Thus far, this hypothesis has been tested only for extra-foveal retinal locations. We tested this hypothesis using two foveal scotomas: scotoma to dim light and scotoma to blue light. We found that the perceived position of a dim dot is extrapolated into the fovea during motion-termination. Next, we compared the perceived position shifts of a blue versus a green moving dot. As predicted the extrapolation at motion-termination was only found with the blue moving dot. The results provide new evidence for the correction-for-extrapolation hypothesis for the region with highest spatial acuity, the fovea.
Multisensory perception and action: development, decision-making, and neural mechanisms
Zhuanghua Shi,Hermann J. Müller
Frontiers in Integrative Neuroscience , 2013, DOI: 10.3389/fnint.2013.00081
Modulation of tactile duration judgments by emotional pictures
Zhuanghua Shi,Hermann J. Müller
Frontiers in Integrative Neuroscience , 2012, DOI: 10.3389/fnint.2012.00024
Abstract: Judging the duration of emotional stimuli is known to be influenced by their valence and arousal values. However, whether and how perceiving emotion in one modality affects time perception in another modality is still unclear. To investigate this, we compared the influence of different types of emotional pictures—a picture of threat, disgust, or a neutral picture presented at the start of a trial—on temporal bisection judgments of the duration of a subsequently presented vibrotactile stimulus. We found an overestimation of tactile duration following exposure to pictures of threat, but not pictures of disgust (even though these scored equally high on arousal), in a short-range temporal bisection task (range 300/900 ms). Follow-up experiments revealed that this duration lengthening effect was abolished when the range to be bisected was increased (1000/1900 ms). However, duration overestimation was maintained in the short-range bisection task regardless of whether the interval between the visual and tactile events was short or long. This pattern is inconsistent with a general arousal interpretation of duration distortion and suggests that crossmodal linkages in the processing of emotions and emotional regulation are two main factors underlying the manifestation of crossmodal duration modulation.
Interaction of Perceptual Grouping and Crossmodal Temporal Capture in Tactile Apparent-Motion
Lihan Chen,Zhuanghua Shi,Hermann J. Müller
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0017130
Abstract: Previous studies have shown that in tasks requiring participants to report the direction of apparent motion, task-irrelevant mono-beeps can “capture” visual motion perception when the beeps occur temporally close to the visual stimuli. However, the contributions of the relative timing of multimodal events and the event structure, modulating uni- and/or crossmodal perceptual grouping, remain unclear. To examine this question and extend the investigation to the tactile modality, the current experiments presented tactile two-tap apparent-motion streams, with an SOA of 400 ms between successive, left-/right-hand middle-finger taps, accompanied by task-irrelevant, non-spatial auditory stimuli. The streams were shown for 90 seconds, and participants' task was to continuously report the perceived (left- or rightward) direction of tactile motion. In Experiment 1, each tactile stimulus was paired with an auditory beep, though odd-numbered taps were paired with an asynchronous beep, with audiotactile SOAs ranging from ?75 ms to 75 ms. Perceived direction of tactile motion varied systematically with audiotactile SOA, indicative of a temporal-capture effect. In Experiment 2, two audiotactile SOAs—one short (75 ms), one long (325 ms)—were compared. The long-SOA condition preserved the crossmodal event structure (so the temporal-capture dynamics should have been similar to that in Experiment 1), but both beeps now occurred temporally close to the taps on one side (even-numbered taps). The two SOAs were found to produce opposite modulations of apparent motion, indicative of an influence of crossmodal grouping. In Experiment 3, only odd-numbered, but not even-numbered, taps were paired with auditory beeps. This abolished the temporal-capture effect and, instead, a dominant percept of apparent motion from the audiotactile side to the tactile-only side was observed independently of the SOA variation. These findings suggest that asymmetric crossmodal grouping leads to an attentional modulation of apparent motion, which inhibits crossmodal temporal-capture effects.
Reducing Bias in Auditory Duration Reproduction by Integrating the Reproduced Signal
Zhuanghua Shi, Stephanie Ganzenmüller, Hermann J. Müller
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0062065
Abstract: Duration estimation is known to be far from veridical and to differ for sensory estimates and motor reproduction. To investigate how these differential estimates are integrated for estimating or reproducing a duration and to examine sensorimotor biases in duration comparison and reproduction tasks, we compared estimation biases and variances among three different duration estimation tasks: perceptual comparison, motor reproduction, and auditory reproduction (i.e. a combined perceptual-motor task). We found consistent overestimation in both motor and perceptual-motor auditory reproduction tasks, and the least overestimation in the comparison task. More interestingly, compared to pure motor reproduction, the overestimation bias was reduced in the auditory reproduction task, due to the additional reproduced auditory signal. We further manipulated the signal-to-noise ratio (SNR) in the feedback/comparison tones to examine the changes in estimation biases and variances. Considering perceptual and motor biases as two independent components, we applied the reliability-based model, which successfully predicted the biases in auditory reproduction. Our findings thus provide behavioral evidence of how the brain combines motor and perceptual information together to reduce duration estimation biases and improve estimation reliability.
Duration reproduction with sensory feedback delay: differential involvement of perception and action time
Stephanie Ganzenmüller,Zhuanghua Shi,Hermann J. Müller
Frontiers in Integrative Neuroscience , 2012, DOI: 10.3389/fnint.2012.00095
Abstract: Previous research has shown that voluntary action can attract subsequent, delayed feedback events toward the action, and adaptation to the sensorimotor delay can even reverse motor-sensory temporal order judgments. However, whether and how sensorimotor delay affects duration reproduction is still unclear. To investigate this, we injected an onset- or offset-delay to the sensory feedback signal from a duration reproduction task. We compared duration reproductions within (visual, auditory) modality and across audiovisual modalities with feedback signal onset- and offset-delay manipulations. We found that the reproduced duration was lengthened in both visual and auditory feedback signal onset-delay conditions. The lengthening effect was evident immediately, on the first trial with the onset-delay. However, when the onset of the feedback signal was prior to the action, the lengthening effect was diminished. In contrast, a shortening effect was found with feedback signal offset-delay, though the effect was weaker and manifested only in the auditory offset-delay condition. These findings indicate that participants tend to mix the onset of action and the feedback signal more when the feedback is delayed, and they heavily rely on motor-stop signals for the duration reproduction. Furthermore, auditory duration was overestimated compared to visual duration in crossmodal feedback conditions, and the overestimation of auditory duration (or the underestimation of visual duration) was independent of the delay manipulation.
Newman-Watts Particle Swarm Optimization with Group Decision
Zhuanghua Zhu
Journal of Computers , 2011, DOI: 10.4304/jcp.6.8.1578-1584
Abstract: Particle swarm optimization (PSO) is a novel swarm intelligent algorithm inspired by fish schooling and birds flocking. Due to the complex nature of engineering optimization tasks, the standard version can not always meet the optimization requirements. Therefore, in this paper, a new group decision mechanism is introduced to PSO to enhance the escaping capability from local optimum. Furthermore, a Watts Strogatz small-world model is incorporated into PSO to increase the population diversity.Seven famous numerical benchmarks are used to testify the new algorithm. Simulation results show it achieves the best performance when compared with three other variants of particle swarm optimization especially for multi-modal problems.

Shen Mowei,Shi Zhuanghua,Zhang Guangqiang,Zhang Feng,

心理学报 , 2004,
Abstract: Visual completion is constantly used by the visual system to deal with image data that is missing, ambiguous or corrupted. In recent years, there have been a large number of researches on visual completion. Although many researches reported that visual completion is based on Gestalt law in a common depth surface, little is known about the visual completion process among different depth surfaces. In this study fragments of Chinese characters were used to investigate the effects of binocular disparity, color and occlusion in visual completion. The results indicated that binocular disparity and color hinder the visual completion process. Occlusion facilitates global visual integration, and that global visual integration may inhibit those separation effects when high-level perceptual processing is involved under such occlusion conditions.
A High Efficiency Spread Spectrum Scheme Using Approximate Orthogonal Complex Sequences  [PDF]
Xiaohong SHI
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2010, DOI: 10.4236/ijcns.2010.31011
Abstract: This paper presents a high efficiency spread spectrum scheme using approximate orthogonal complex (AOC) sequences. In this scheme, the 64 AOC sequences picked up from 84 complex sequences space are employed for spreading spectrum. In modulation, 6 input bits is used to select one AOC sequence, and the selected sequence is then phase-rotated by another 2 input bits. In demodulator, a complex correlator detects the transmitted AOC sequence. Simulation results show that the proposed scheme has better BER performance than the existing complementary code keying (CCK) modulation scheme. For AOC, additional processing gain of 1.79dB can be obtained when the sequence length is 8.
Foundations of Intelligence Science  [PDF]
Zhongzhi Shi
International Journal of Intelligence Science (IJIS) , 2011, DOI: 10.4236/ijis.2011.11002
Abstract: In order to make significant progress toward achievement of human level machine intelligence a paradigm shift is needed. More specifically, the natural intelligence and artificial intelligence should be closely interacted in Intelligence Science study, instead of separate from each other. In order to reach the paradigm, brain science, cognitive science, artificial intelligence and others should cross-research together. Brain science explores the essence of brain, research on the principle and model of natural intelligence in molecular, cell and behavior level. Cognitive science studies human mental activity, such as perception, learning, memory, thinking, consciousness etc. Artificial intelligence attempts simulation, extension and expansion of human intelligence using artificial methodology and technology. All together pursue to explore the mechanism and principle of intelligence which is the engine of advanced science and technology. The paper will give the definition of intelligence and discuss ten big issues of Intelligence Science. The conclusion and perspective will be given in last section.
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