We have measured, at various wavelengths, the spiral arm pitch angles of a sample distant galaxies from Hubble Space Telescope eXtreme Deep Field (XDF). According to density wave theory, we should detect colour jumps red-to-blue across arms. Colour are consequence large-scale shocks, which also generate classic blue-to-red age/colour gradients, and only been detected until now in nearby galaxie...

After being neglected during many decades, airships are experiencing a new interest, specially the stratospheric lighter than air vehicle. This paper presents a nonlinear motion control method of a dirigible in a high constant altitude flight, for path tracking. We use the property that the system is input/output linearizable. In path generation, we use the cubic spiral while the polynomial app...

Contemporary cochlear implants with multiple electrode stimulation can produce good speech perception but poor music perception. Hindered by the lack of a gold standard to quantify electric pitch, relatively little is known about the nature and extent of the electric pitch abnormalities and their impact on cochlear implant performance. Here we overcame this obstacle by comparing acoustic and el...

A freeying space robot with a 6 DOF manipulator cannot follow an arbitrary trajectory in the 9D generalized coordinates(3 of the satellite orientation and 6 of the manipulator) with only manipulator joint control, though it was shown to be commonly controllable in the literature. In this paper, we propose a method to approximate the desired 9D path by introducing a perturbation around it. We ca...

A method for family of G Pythagorean hodograph (PH) quintic spiral transition from straight line to circle is discussed in this paper. This method is then extended to a pair of spirals between two straight lines or two circles. We derive a family of quintic transition spiral curves joining them. Due to flexibility and wide range of shape control parameters, our method can be easily applied for ...

A method for family of G planar cubic Bézier spiral transition from straight line to circle is discussed in this paper. This method is then extended to a pair of spirals between two straight lines or two circles. We derive a family of cubic transition spiral curves joining them. Due to flexibility and wide range of shape control parameters, our method can be easily applied for practical applica...

Comparative misalignment disturbance functions (MDF) have been measured for rotations between display and control axes for pure pitch, roll, and yaw misalignments in a high fidelity virtual environment. Twenty participants manually moved a virtual cursor using position control to touch 3-dimensionally, randomly presented nearby targets having a constant Fitts Index of Difficulty. Results show a...