No abstract

Smooth pursuit eye movements superimpose additional motion on the retinal image of untracked visual targets, potentially leading to the perception of motion smear and a distortion of the perceived direction of motion. Previously, we demonstrated an attenuation of perceived motion smear when the untracked target moves in the opposite direction of an ongoing pursuit eye movement. In this study, the extent of perceived motion smear and the direction of perceived smear were compared for a single bright dot that moved in a wide range of directions with respective to horizontal pursuit at 8 deg/s. Comparable data were obtained during fixation as a control. The results indicate that a significant attenuation of perceived motion smear occurs when the dot's motion includes a horizontal component in the opposite direction of eye movement. In contrast, the direction of perceived smear approximates the trajectory of the retinal image motion, during both fixation and pursuit. These results suggest a selective application of extra-retinal signals to compensate specific aspects of visual perception that results from the retinal image motion during smooth pursuit eye movements.

Purpose The purpose of this paper is to increase flight performance of small unmanned aerial vehicle (UAV) using simultaneous UAV and autopilot system design. Design/methodology/approach A small UAV is manufactured in Erciyes University, College of Aviation, Model Aircraft Laboratory. Its wing and tail is able to move forward and backward in the nose-to-tail direction in prescribed interval. Autopilot parameters and assembly position of wing and tail to fuselage are simultaneously designed to maximize flight performance using a stochastic optimization method. Results are obtained are used for simulations. Findings Using simultaneous UAV and autopilot system design idea, flight performance is maximized. Research limitations/implications Permission of Directorate General of Civil Aviation in Turkey is required for testing UAVs in long range. Practical implications Simultaneous design idea is very beneficial for improving UAV flight performance. Originality/value Creating a novel method to improve flight performance of UAV and developing an algorithm performing simultaneous design idea.

When a figure moves behind a stationary narrow slit, observers often report seeing the figure as an integrated whole, a phenomenon known as slit viewing or anorthoscopic perception. Interestingly, in slit viewing, the figure is perceived compressed along the axis of motion, e.g., a circle is perceived as an ellipse. Underestimation of the speed of the moving object was offered as an explanation for this apparent compression. We measured perceived speed and compression in anorthoscopic perception and found results that are inconsistent with this hypothesis. We found evidence for an alternative hypothesis according to which apparent compression results from perceived speed differences between different parts of the figure, viz., the trailing parts are perceived to move faster than the leading parts. These differences in the perceived speeds of the trailing and the leading edges may be due to differences in the visibilities of the leading and trailing parts. We discuss our findings within a non-retinotopic framework of form analysis for moving objects.

Thanks to their superior mechanical properties, polymer matrix composites have gained considerable importance. In order to improve the impact resistance of polymer matrix composite materials, a new hybrid material known as fiber metal laminate (FML) has been developed. The aim of this study was to reveal the effect of stacking sequence (SS), metal volume fraction (MVF), and number of layers on ballistic resistance in fiber metal laminates (FMLs). Four types of FMLs in different sequences and MVF (25% and 50%) were produced with hot press and vacuum. Ballistic tests were carried out with a single stage gas gun system. The absorbed energy was calculated from the energy difference that occurred by taking into account the FMLs entry and exit velocity of the projectile and the projectile mass. Damage types were examined after ballistic testing. It was determined that the stacking sequence and MVF significantly affect the impact resistance of FMLs. It was determined that the metal layer, which first encounters the projectile, compared to the polymer matrix composite, is more effective on the impact resistance of FMLs, and the impact resistance increased with the increase of MVF. In addition, the increase in the number of layers, if the top layers remain the same, adversely affected the impact resistance. It was observed that the first layer that encounters the projectile and the amount of MVF have a significant effect on the ballistic impact strength. As the amount of MVF increases, the ballistic impact resistance increases.