Comparison of the Wii Balance Board System and Foam Posturography System in Assessing Postural Balance.

OBJECTIVE: Falls are a major cause of disability and mortality in the elderly. Postural balance is associated with falls and can be evaluated by posturography. However, conventional posturography is costly and requires a sufficiently large space to perform. Hence, this study developed a portable system to meet the requirement of field studies, and investigated its reliability and validity. DESIGN: A custom-written software application was developed to link a computer to the Nintendo Wii balance board (WBB) and the center of pressure was acquired, which was then compared with that obtained from commercially available foam posturography (FP). Forty younger adults including 20 patients with peripheral vestibular disorders as well as 20 healthy controls, and 50 older patients with peripheral vestibular disorders were enrolled. All subjects underwent postural balance testing using the WBB system (WBSS) and FP system (FPS) in a randomized order. RESULTS: For the intersystem reliability, although the WBSS obtained a significantly smaller mean sway area than the FPS, both systems revealed adequate to excellent reliability with an intraclass correlation coefficient (ICC) of 0.67 to 0.87. The WBBS showed adequate to excellent test-retest reliability (ICC: 0.53 to 0.88). For the validity, the respective cutoff sway areas were 1.03 and 3.09 cm 2 under conditions C and D via the WBBS for discriminating the fallers from nonfallers. CONCLUSION: The WBBS yielded adequate to excellent reliability and validity for accessing postural balance, and had good performance in discriminating the fallers from nonfallers. The WBBS has advantages over the commercial FPS of low cost, easy portability, programmability, and may be better-suited to mass detection and research programs. Most importantly, this WBBS can be performed outside the hospital for testing postural balance, especially in the elderly.

ConcentrateNet: Multi-Scale Object Detection Model for Advanced Driving Assistance System Using Real-Time Distant Region Locating Technique.

This paper proposes a deep learning based object detection method to locate a distant region in an image in real-time. It concentrates on distant objects from a vehicular front camcorder perspective, trying to solve one of the common problems in Advanced Driver Assistance Systems (ADAS) applications, which is, to detect the smaller and faraway objects with the same confidence as those with the bigger and closer objects. This paper presents an efficient multi-scale object detection network, termed as ConcentrateNet to detect a vanishing point and concentrate on the near-distant region. Initially, the object detection model inferencing will produce a larger scale of receptive field detection results and predict a potentially vanishing point location, that is, the farthest location in the frame. Then, the image is cropped near the vanishing point location and processed with the object detection model for second inferencing to obtain distant object detection results. Finally, the two-inferencing results are merged with a specific Non-Maximum Suppression (NMS) method. The proposed network architecture can be employed in most of the object detection models as the proposed model is implemented in some of the state-of-the-art object detection models to check feasibility. Compared with original models using higher resolution input size, ConcentrateNet architecture models use lower resolution input size, with less model complexity, achieving significant precision and recall improvements. Moreover, the proposed ConcentrateNet architecture model is successfully ported onto a low-powered embedded system, NVIDIA Jetson AGX Xavier, suiting the real-time autonomous machines.

Localization of Interacting Dirac Fermions.

Using exact quantum Monte Carlo calculations, we examine the interplay between localization of electronic states driven by many-body correlations and that by randomness in a two-dimensional system featuring linearly vanishing density of states at the Fermi level. A novel disorder-induced nonmagnetic insulating phase is found to emerge from the zero-temperature quantum critical point separating a semimetal and a Mott insulator. Within this phase, a phase transition from a gapless Anderson-like insulator to a gapped Mott-like insulator is identified. Implications of the phase diagram are also discussed.

Erratum: Pomeranchuk Cooling of SU(2N) Ultracold Fermions in Optical Lattices [Phys. Rev. Lett. 110, 220401 (2013)].

This corrects the article DOI: 10.1103/PhysRevLett.110.220401.

Pomeranchuk cooling of SU(2N) ultracold fermions in optical lattices.

We investigate the thermodynamic properties of a half-filled SU(2N) Hubbard model in the two-dimensional square lattice by the method of the determinant quantum Monte Carlo simulation, which is free of the fermion "sign problem." The large number of hyperfine-spin components enhances spin fluctuations, which facilitates the Pomeranchuk cooling to temperatures comparable to the superexchange energy scale in the case of SU(6). Various physical quantities including entropy, charge fluctuations, and spin correlations are calculated.

Engineering of many-body Majorana states in a topological insulator/s-wave superconductor heterostructure.

We study a vortex chain in a thin film of a topological insulator with proximity-induced superconductivity-a promising platform to realize Majorana zero modes (MZMs)-by modeling it as a two-leg Majorana ladder. While each pair of MZMs hybridizes through vortex tunneling, we hereby show that MZMs can be stabilized on the ends of the ladder with the presence of tilted external magnetic field and four-Majorana interaction. Furthermore, a fruitful phase diagram is obtained by controlling the direction of magnetic field and the thickness of the sample. We reveal many-body Majorana states and interaction-induced topological phase transitions and also identify trivial-superconducting and commensurate/incommensurate charge-density-wave states in the phase diagram.

Direct observation of nodes and twofold symmetry in FeSe superconductor.

We investigated the electron-pairing mechanism in an iron-based superconductor, iron selenide (FeSe), using scanning tunneling microscopy and spectroscopy. Tunneling conductance spectra of stoichiometric FeSe crystalline films in their superconducting state revealed evidence for a gap function with nodal lines. Electron pairing with twofold symmetry was demonstrated by direct imaging of quasiparticle excitations in the vicinity of magnetic vortex cores, Fe adatoms, and Se vacancies. The twofold pairing symmetry was further supported by the observation of striped electronic nanostructures in the slightly Se-doped samples. The anisotropy can be explained in terms of the orbital-dependent reconstruction of electronic structure in FeSe.