Underwater Terrain Positioning Method Based on Least Squares Estimation for AUV

To achieve accurate positioning of autonomous underwater vehicles, an appropriate underwater terrain database storage format for underwater terrain-matching positioning is established using multi-beam data as underwater terrainmatching data. An underwater terrain interpolation error compensation method based on fractional Brownian motion is proposed for defects of normal terrain interpolation, and an underwater terrain-matching positioning method based on least squares estimation（LSE） is proposed for correlation analysis of topographic features. The Fisher method is introduced as a secondary criterion for pseudo localization appearing in a topographic features flat area, effectively reducing the impact of pseudo positioning points on matching accuracy and improving the positioning accuracy of terrain flat areas. Simulation experiments based on electronic chart and multi-beam sea trial data show that drift errors of an inertial navigation system can be corrected effectively using the proposed method. The positioning accuracy and practicality are high, satisfying the requirement of underwater accurate positioning.

THE ROLE OF FRONTAL NEURONS IN PAIN AND ACUPUNCTURE ANALGESIA

To study the role of frontal neurons in pain and acupuncture analgesia, experiments were carried out on 4 monkeys (Macaca mulatta) during performing two tasks, the Heat Discrimination Response GO/NO-GO Task (Task Ⅰ) and the Heat Delayed Discrimination GO/NO-GO Task (Task Ⅱ). After a criterion of 90% of correct performances over three successive days had been reached, activity of single neurons was recorded from the frontal cortex. Of 276 Task Ⅰ-related neurons, 211 responded to noxious and/or innocuous heat stimuli. Of 73 Task Ⅱ-related neurons, 59 responded to noxious and/or innocuous heat stimuli. During acupuncture, the nociceptive reaction time for lever release to avoid painful stimuli was increased, the percentage of correct performances was lowered, and the neuronal responses to noxious and/or innocuous stimuli were suppressed. These neurons were mainly located in a circumscribed area medial to the superior ramus of the arcuate sulcus in frontal cortex, including the prefrontal and premotor

COMPUTER SIMULATIONS OF FIGURE-GROUND DISCRIMINATION IN THE VISUAL SYSTEM OF THE FLY

Figure-ground discrimination and pattern discrimination represent one of the most important problems in computer vision. Based on computational neuronal network model proposed by Reichardt et al. for figure-ground discrimination in the visual system of the fly, entire systematic computer simulations were carried out under nonstationary conditions. Results show that the model network and simulations have predictive power for behavioural experimental results. This paper proposes that motion perception and elementary pattern discrimination in human visual system may be mediated by some kind of figure-ground system with movement detectors as input layer.