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To examine the issue of whether attentional focus can split among noncontiguous locations, Wright and Richard (2003) used a multiple-cue display and found the validity effect for each of the multiple cues. However, they argued against the multiple foci account by claiming that the multiple-cue effect they obtained was stimulus-driven. We doubt whether their cues were indeed exogenous as they claimed since their target could appear in any one of the eight possible locations but the cue validity was set at 50%. In this case, the cue was in fact predictive as to the target location. In the current study, we showed that when the cues were designed to be truly nonproductive (12.5%), the multiple-cue effect was eliminated (Experiment 2). We replicated the multiple-cue effect when the cue validity was 50%, as in Wright and Richard (Experiment 1), and showed that there was a cue-triggered, attentional-orienting effect but not visual search advantage when the cue remained on the target display (Experiment 3). Our results, therefore, highlight the possibility of involvements of top-down controls in the validity effect found for multiple-cue displays and the importance of taking predictability into consideration in the testing of hypotheses derived from attention theories. Keywords: top-down, bottom-up, spatial cueing, cue validity, probability In the debate on whether attentional focus can split into different spatial locations, some argue that attention can split and process multiple stimuli at nonadjacent spatial locations (e.g., Awh & Pashler, 2000; Alvarez & Cavanagh, 2005; McMains & Somers, 2004; Schmidt, Fisher, & Pylyshyn, 1998), while others argue that attention cannot split and the effects observed from multiple locations are in fact achieved by a unitary focus. For those who defended the latter position, they explained the apparent effect of multiple foci by a unitary focal attention that shifts rapidly between locations (e.g., Kramer & Hahn, 1995; VanRullen, Carlson, & Cavanagh, 2007), distributes across continuous space in a grathent fashion (e.g., LaBerge & Brown, 1989), or is mediated by preattentive, stimulus-driven "indexes" (e.g., Pylyshyn & Storm, 1988; Solomon, 2004; Wright, 1994; Wright & Richard, 2003). Among those advocates of the unitary-attentional-focus view, Wright and Richard (2003) emphasised that while attentional focus is unitary, multiple locations can be "registered" preattentively (i.e., stimulus driven) and receive higher priority in further processing. For this argument to be valid, ensuring that the multiplelocation effect is purely stimulus-driven rather than controlled by several top-down attentional foci is important. Wright and Richard reported such a case in a multiple-cue display. However, we suspect that their multiple-cue conditions were confounded with the validity manipulation of the cues, making part of their findings not purely stimulus-driven. Specifically, we argue that the cues they used were not exogenous because their target could appear at one of eight possible locations but the cue validity was set at 50%. We aimed at empirically demonstrating that once the cue validity is manipulated at chance level according to the number of the cues (i.e., 12.5% for one cue and 25% for two cues, etc.), the multiplecue effect should disappear. If so, this should indicate the involvement of top-down controls, and thus, it cannot be purely stimulusdriven. In Wright and Richard (2003)'s Experiment 1, one, two, three, or four cues were shown before the presence of the target. (Figure 1 shows the two-cue condition). The task was to judge the orientation of the target, which was a tilt bar. The cues were horizontal bars presented at the possible locations of the target. When the target was presented on top of any one of the cues, it was defined as the valid condition (Figure 1C), and when the target was presented at an empty space that was not preoccupied by any cue, it was defined as the invalid condition. …

Due to the bandwidth constraints of multi-view autostereoscopic display that severely restrict number of views simultaneously displayed without degrading resolution or increasing display cost unacceptably. The alternative way is the eye tracking technology, which can fluently rendering and accurately projecting the stereo video to the viewer. In order to render stereo content with respect to user's view points and to optically project the content onto the left and right eyes of the user accurately, the real-time viewer tracking technique that allows the user to move around freely when watching the autostereoscopic display is developed in this study. It comprises the face detection by using multiple eigenspaces of various lighting conditions, fast block matching for tracking four motion parameters of the user's face region. The Edge Orientation Histogram (EOH) on Real AdaBoost to improve the performance of original AdaBoost algorithm using Haar feature in OpenCV library developed by Intel is also applied in this study. Since performance of the viewer tracking autostereoscopic display is still influenced under variant environmental conditions, the robustness and efficiency of the viewer-tracking system are evaluated in this study.

An autostereoscopic display provides users great enjoyment of stereo visualization without uncomfortable and inconvenient drawbacks of wearing stereo glasses. However, bandwidth constraints of current multi-view 3D display severely restrict the number of views that can be simultaneously displayed without degrading resolution or increasing display cost unacceptably. An alternative to multiple view presentation is that the position of observer can be measured by using viewer-tracking sensor. It is a very important module of the viewer-tracking component for fluently rendering and accurately projecting the stereo video. In order to render stereo content with respect to user's view points and to optically project the content onto the left and right eyes of the user accurately, the real-time viewer tracking technique that allows the user to move around freely when watching the autostereoscopic display is developed in this study. It comprises the face detection by using multiple eigenspaces of various lighting conditions, fast block matching for tracking four motion parameters of the user's face region. The Edge Orientation Histogram (EOH) on Real AdaBoost to improve the performance of original AdaBoost algorithm is also applied in this study. The AdaBoost algorithm using Haar feature in OpenCV library developed by Intel to detect human face and enhance the accuracy performance with rotating image. The frame rate of viewer tracking process can achieve up to 15 Hz. Since performance of the viewer tracking autostereoscopic display is still influenced under variant environmental conditions, the accuracy, robustness and efficiency of the viewer-tracking system are evaluated in this study.

There are lots of handicaps and elders in the world. Many of them are not able to move as easily as normal people. It is useful if we develop an automatic wheelchair to help them move more freely. In this paper we proposed a design of small-area automatic wheelchair to help handicaps or elders be able to move easily in a small area. The most concern in this project is low cost with acceptable performance rather than high velocity or high accuracy. The design integrates several technologies to apply on the wheelchair, including wireless positioning, automatic mobile technology, and wireless communication. On the other hand, we proposed a design that duplicable information can be computed on server side, and information which is not duplicable can be computed in constant time. Therefore, our design of small-area automatic wheelchair can cost very little. We also proposed a design of building map information to make the whole design more complete.