Head coupled perspective is often considered to be an essential aspect of stereoscopic desktop virtual reality (VR) systems. Such systems use a tracking device to determine the user’s head pose in up to six degrees of freedom (DOF). Users of desktop VR systems perform their task while sitting down and therefore the extent of head movements is limited. This paper investigates the validity of usi...

Background: Forward head posture is one of the most prevalent abnormal postures in patients with neck disorders. The aim of this study was to evaluate the effects of forward head posture on gait ground reaction force characteristics in children. Methods: Twelve children with forward head posture (age: 11.8±1.3 years) and sixteen healthy control children (...

Tracking also called Position and Orientation Tracking or Position Tracking and mapping, is used in VEs where the orientation and the position of a real physical object is required. Specifying a point in 3-D requires the transition position, that is the Cartesian coordinates x, y, and z. However, many VE applications manipulate entire objects and this requires the orientation to be specified by...

This study assessed the relative contributions of visual and proprioceptive/motor information during self-motion in a virtual environment using a speed discrimination task. Subjects wore a head-mounted display and rode a stationary bicycle along a straight path in an empty, seemingly infinite hallway with random surface texture. For each trial, subjects were required to pedal the bicycle along ...

BACKGROUND While most reports of component fracture following alumina-on-alumina total hip arthroplasty have involved the acetabular liner, few have involved fracture of the alumina femoral head. In the present multicenter study, we investigated ceramic head fractures in a cohort of patients who underwent third-generation alumina-on-alumina total hip arthroplasty. METHODS We performed a retro...

Pilomatrixomas are benign neoplasms of the hair follicle, presenting as a mass in the head and neck region. Those arising from the parotid region may pose a diagnostic challenge. We present six patients (age range 6 to 68 years) with pilomatrixoma in the head and neck region. The lesions were located in the preauricular region in two cases, and in the periorbital region, the forehead, the neck,...

The existing five degree of freedom HITS sensor used to measure head accelerations is incapable of measuring rotational head acceleration about the z-axis. A new six degree of freedom (6DOF) sensor has been developed capable of measuring linear and rotational accelerations for each axis. The 6DOF sensor consists of 12 accelerometers that integrate into football helmets and communicate wirelessl...