The trajectory of a photon emitted by an accelerating light source. The apparent motion of a light source

In this article the concept of ``tachy-photons'' is introduced. The tachy-photons are photons emitted by an accelerating light source. The tachy-photons can travel faster than the speed of light, but their average speed is equal to the speed of light. Using the trajectories of tachy-photons, the apparent motion of an accelerating light source is calculated. This apparent motion of the light source is dramatically different from its actual motion.

The Ring Rotation Illusion: Properties and Links of a Novel Illusion of Motion

We report a novel visual illusion we call the Ring Rotation Illusion (RRI). When a ring of stationary points replaces a circular outline, the ring of points appears to rotate to a halt, although no actual motion has been displayed. Three experiments evaluate the clarity of the illusory rotation. Clarity decreased as the diameter of the circle and ring increased and increased as the number of points forming the ring increased. The optimal interstimulus interval (ISI) between the circle and ring was 90 ms when stimulus presentations lasted 100 ms but 0 ms with 500 ms presentations. We compare the RRI to the Motion Bridging Effect (MBE), a similar illusion in which a stationary ring of points replaces an initial ring of points that spins so rapidly it looks like a stationary outline. A rotation of the stationary ring is seen that usually matches the direction of the initial ring’s invisible spin. Participants reported a slightly more frequent and clearer motion percept with the MBE than RRI. ISI manipulations had similar effects on the two illusions, but the effects of number of points and ring diameter were largely restricted to the RRI. We suggest that both the RRI and MBE motion percepts are produced by a visual heuristic that holds that the transition from an outline circle to a ring of points is plausibly explained by a rapid spin decelerating to a halt, but in the case of the MBE, an additional direction-sensitive mechanism contributes to this percept.

Beyond sensory conflict: The role of beliefs and perception in motion sickness

Illusory self-motion often provokes motion sickness, which is commonly explained in terms of an inter-sensory conflict that is not in accordance with previous experience. Here we address the influence of cognition in motion sickness and show that such a conflict is not provocative when the observer believes that the motion illusion is indeed actually occurring. Illusory self-motion and motion sickness were elicited in healthy human participants who were seated on a stationary rotary chair inside a rotating optokinetic drum. Participants knew that both chair and drum could rotate but were unaware of the actual motion stimulus. Results showed that motion sickness was correlated with the discrepancy between participants’ perceived self-motion and participants’ beliefs about the actual motion. Together with the general motion sickness susceptibility, this discrepancy accounted for 51% of the variance in motion sickness intensity. This finding sheds a new light on the causes of visually induced motion sickness and suggests that it is not governed by an inter-sensory conflict per se, but by beliefs concerning the actual self-motion. This cognitive influence provides a promising tool for the development of new countermeasures.

Dynamic research and analysis for a wheel-legged harvester chassis during tilting process

This article aims to analyze the dynamic tilting characteristics of a four-wheel-legged harvester chassis. In order to achieve the pose and position of the chassis, kinematic model of a four-wheel-legged harvester chassis was established by the screw theory method. After analyzing the actual motion of the chassis during tilting process, dynamic tilting model of the wheel-legged articulated steering chassis was achieved based on the Lagrange’s equation. To prove the accuracy of the dynamic model, simulations of the chassis was conducted under ADAMS environment. Three series of comparisons showed that results between simulations and calculations were highly consistent. Both results showed that lifting the tilting side wheel-legs, shortening the other side legs, and steering to the tilting side could help prevent tilting of the chassis. Lifting the tilting side wheel-legs was proved to be more efficient than shortening that of the other sides. Average error of the change rates between simulations and calculations were 2.4%, 0.67%, and 2.75%.

The Role of Motion Verbs in Conveying Path-Related Information in English and Slovene Fictive Motion Expressions

The paper presents a study on fictive motion (FM) uses of motion verbs in English and slovene from the point of view of conveying path-related information. An FM expression describes a static scene in terms of motion (e.g. The road weaves through a range of hills). Motion verbs in FM uses do not describe actual motion events, but may refer to certain properties of the path by virtue of their meanings. English and slovene FM expressions exhibit different behaviours in this respect. Many English verbs display meaning components that can be metonymically mapped onto the properties of the path. The meanings of slovene verbs are less specific, so that such properties need to be expressed verb-externally in slovene FM expressions.

The post-Newtonian approximation

This chapter embarks on a study of the two-body problem in general relativity. In other words, it seeks to describe the motion of two compact, self-gravitating bodies which are far-separated and moving slowly. It limits the discussion to corrections proportional to v2 ~ m/R, the so-called post-Newtonian or 1PN corrections to Newton’s universal law of attraction. The chapter first examines the gravitational field, that is, the metric, created by the two bodies. It then derives the equations of motion, and finally the actual motion, that is, the post-Keplerian trajectories, which generalize the post-Keplerian geodesics obtained earlier in the chapter.