This article handles the problem of validating the results of nested (as opposed to ”flat”) clusterings. It shows that standard external validation indices used for partitioning clustering validation, like Rand statistics, Hubert Γ statistic or F-measure are not applicable in nested clustering cases. Additionally to the work, where F-measure was adopted to hierarchical classification as hF-meas...

Based on the generalized Lorenz-Mie theory (GLMT), this paper reveals, for the first time in the literature, the principal characteristics of the optical forces and radiation pressure cross-sections exerted on homogeneous, linear, isotropic and spherical hypothetical negative refractive index (NRI) particles under the influence of focused Gaussian beams in the Mie regime. Starting with ray opti...

Wavefront sensor noise and fidelity place a fundamental limit on achievable image quality in current adaptive optics ophthalmoscopes. Additionally, the wavefront sensor 'beacon' can interfere with visual experiments. We demonstrate real-time (25 Hz), wavefront sensorless adaptive optics imaging in the living human eye with image quality rivaling that of wavefront sensor based control in the sam...

We present multiphoton microendoscopy with a rotational probe and a 1 m fiber-based femtosecond laser. The rotational probe is based on a double-clad photonic crystal fiber, a gradient index lens, a microprism, and a rotational microelectronicmechanical system (MEMS) motor. The MEMS motor has a diameter of 2.2 mm and can provide 360° full-view rotation. The fiber laser provides ultrashort pulse...

The purpose of this report is to present the results of further investigations into the operation and design of two-dimensional Luneburg Lenses at 24 GHz, with the possibility for electronic control of their behavior. Various lens design techniques are illustrated; these include a holey dielectric lens (drilled dielectric) and, a holey plate lens (etched holes on the upper metal plate). Ray tra...

We have analyzed the physical origins of the temperature gradient of the ordinary refractive index ( dn(o) /dT) of liquid crystals. To achieve a large dn(o) /dT , high birefringence and low clearing temperature play crucial roles. Based on these simple guidelines, we formulated two exemplary liquid crystal mixtures, designated as UCF-1 and UCF-2, and compared their physical properties with a co...

Neurons in the dorsal region of the medial superior temporal area (MSTd) have previously been shown to respond to the expanding radial motion that occurs as an observer moves through the environment. In previous experiments, MSTd neurons were tested with radial and circular motion centered in the visual field. However, different directions of observer motion, relative to the direction of gaze, ...