RESUMO
In this paper, in order to overcome certain limitations of previously commercialized platforms, a new integrated unmanned surface vehicle (USV) and unmanned underwater vehicle (UUV) platform connected via underwater cable capable of acquiring real-time underwater data and long-time operation are studied. A catamaran-type USV was designed to overcome the limitations of an ocean environment and to play the role as the hub of power supply and communication for the integrated platform. Meanwhile, the UUV was designed as torpedo-shaped to minimize hydrodynamic resistance and its hardware design was focused on processing and sending the underwater camera and sonar data. The underwater cable driven by a winch system was installed to supply power from the USV to the UUV and to transmit acquired data form underwater sonar sensor or camera. Different from other previously studied cooperation system of USVs and autonomous underwater vehicles (AUVs), the merit of the proposed system is real-time motion coordination control between the USV and UUV while transmitting large amount of data using the tether cable. The main focus of the study is coordination of the UUV with respect to the global positioning system (GPS) attached at USV and verification of its performance throughout field tests. Waypoint tracking control algorithm was designed and implemented on USV and relative heading, distance control for USV-UUV coordination was implemented to UUV. To ensure the integrity of the coordination control of the integrated platform, a study on accurate measurement system of the relative position between the USV and the UUV by using the GPS and the ultrashort baseline (USBL) device was performed. Individual tests were conducted to verify the performance of USBL and AHRS, which provide the position and heading data of UUV among the sensors mounted on the actual platform, and the effectiveness of the obtained sensor data is presented. Using the accurate measurement system, a number of field tests were conducted to verify the performance of the integrated platform.
RESUMO
Previously, phytanoyl-CoA alpha-hydroxylase-associated protein 1 (PAHX-AP1) was isolated as a novel neuron-specific protein to interact with Refsum disease (RfD) gene PAHX. Its expression in the brain increased after eyelid opening, and the elevated level was maintained through adulthood. In this report, to verify the hypothesis that light could trigger this increase, we have examined the developmental distribution pattern of PAHX-AP1 in rat retina and visual cortex, and changes of its expression by binocular deprivation. Northern blot analyses demonstrated PAHX-AP1 expression reached its highest level in the visual cortex and eyeball at 4 weeks after birth, and these levels were maintained through adult life. Two weeks after visual deprivation, its expression in the eyeball and visual cortex decreased compared with the control. In situ hybridization analyses of the retina showed that PAHX-AP1 expression was limited to the ganglionic cell layer at 10 days after birth, but expressed in the inner nuclear cell layer and extended to the outer nuclear cell layer at 2 and 3 weeks after birth, respectively. Two weeks after visual deprivation, however, it decreased in the ganglionic and inner nuclear cell layer, and disappeared in the rod and cone cell layers. In the visual cortex, strong signals of PAHX-AP1 were detected in layers IV and VI, and II-VI at 10 days and 2 weeks after birth, respectively. Its expression decreased after 2 weeks of visual deprivation. These results indicate that visual stimulation is essential for the maintenance of PAHX-AP1 expressions in the retina, especially in the rod and cone cell layers, and visual cortex, and suggest that PAHX-AP1 may be involved in the developmental regulation of the photoreceptor's function.
