BACKGROUND Early detection of high-risk population for osteoporosis is the key to preventing this disease. METHODOLOGY In this cross-sectional study a continuous sample of 270 women and 89 men (age: 20-90 years) was divided into four groups by age (≤ 55 or > 55 years) and sex. Participants completed the IOF test. Low-, medium-, and high-risk grades were defined by an OSTA index of greater tha...

deadline 14 November 2003 IOF awards are available for scientists: IOF Claus Christiansen Research Fellow-

New magnitude bounds of the frequency response functions for the Nonlinear AutoRegressive model with eXogenous input (NARX) are investigated by exploiting the symmetry of the nth-order generalized frequency response function (GFRF) in its n frequency variables. The new magnitude bound of the nth-order symmetric GFRF is frequency-dependent, and is a polynomial function of the magnitude of the fi...

THE INTERNATIONAL SOCIETY for Clinical Densitometry (ISCD) periodically convenes a Position Development Conference (PDC) for the purpose of making recommendations on quality control, acquisition, analysis, interpretation, and reporting of bone densitometry. Questions regarding relevant topics are assigned to subcommittees for a comprehensive medical literature review and presentation of a repor...

A kernel method has been developed to model finite degree, finite memory length and infinite degree, finite memory length Volterra series using polynomial and exponential kernels, respectively. Here, the kernel method is extended to identify NARX (Nonlinear AutoRegressive with eXogenous inputs) models. To verify its effectiveness, the proposed approach is used in modeling friction dynamics, whi...

People find their way through cluttered environments with ease and without injury. How do they do it? Two approaches to wayfinding are considered: Differential motion parallax (DMP) is a retinal motion invariant of near and far objects moving against fixation; the information in optical flow (IOF) is a radial pattern of vectors, relying on decomposition of retinal flow. Evidence is presented th...

The field of Operational Modal Analysis (OMA) has recently become an emerging research interest. OMA, also known as Response-Only Modal Analysis, extracts the modal parameters by processing only the system response data. In many experimental measurement situations, the system’s output data series is short in length and buried under potentially correlated noise. In such cases, the separation of ...