InPhase: Phase-based Ranging and Localization

Ranging and subsequent localization have become more and more critical in today’s factories and logistics. Tracking goods precisely enables just-in-time manufacturing processes. We present the InPhase system for ranging and localization applications. It employs narrowband 2.4 GHz IEEE 802.15.4 radio transceivers to acquire the radio channel’s phase response. In comparison, most other systems employ time-of-flight schemes with Ultra Wideband transceivers. Our software can be used with existing wireless sensor network hardware, providing ranging and localization for existing devices at no extra cost. The introduced Complex-valued Distance Estimation algorithm evaluates the phase response to compute the distance between two radio devices. We achieve high ranging accuracy and precision with a mean absolute error of 0.149 m and a standard deviation of 0.104 m. We show that our algorithm is resilient against noise and burst errors from the phase-data acquisition. Further, we present a localization algorithm based on a particle filter implementation. It achieves a mean absolute error of 0.95 m in a realistic 3D live tracking scenario.

Characteristics Associated with Acute-Phase Response following First Zoledronic Acid Infusion in Brazilian Population with Osteoporosis

We aimed to evaluate characteristics associated with acute-phase response (APR) following first zoledronic acid infusion in a Brazilian cohort. This retrospective cohort study enrolled all adults with osteoporosis who underwent a first zoledronic acid infusion at our centre between June 2015 and June 2019. Clinical demographics (age, sex, diabetes, smoking, body mass index, and previous oral bisphosphonate use) and laboratory data (calcium, parathyroid hormone, renal function, and serum 25-hydroxyvitamin D and carboxy-terminal crosslinked telopeptide of type 1 collagen [CTX], both before and after infusion) were compared between patients with and without APR. We evaluated association magnitude between the presence of APR and clinical variables through logistic regression. This study enrolled 400 patients (women, 80%). APR was observed in 24.5% (n = 98) of patients. The mean symptom duration in days was 3.5 ± 2.8. Patients with APR were younger (67 ± 12 vs. 71 ± 11 years; p = 0.001 ), used oral bisphosphonates less frequently (34% × 50%; p = 0.005 ), and had greater baseline CTX (0.535 ng/mL [0.375, 0.697] × 0.430 [0.249, 0.681]; p = 0.03 ) and ΔCTX (−69 [−76; −50] × −54 [−72; −23]; p = 0.002 ) than those without APR. The other variables were similar between the groups. Only ΔCTX was associated (OR, 0.62; 95% CI 0.41–0.98) with APR after accounting for age and bisphosphonate use. APR occurred in 24.5% of the cohort. Younger age and absence of prior oral bisphosphonate use were associated with APR following first zoledronic acid infusion. APR was associated with ΔCTX (but no other variables) after adjusting for these factors.

Numerical simulation of the frequency response and phase response of combined UWB antennas in the receiving-transmitting mode

Results of a simulation and experimental study of a combined ultra-wideband antenna, which is a combination of electric and magnetic dipoles, are presented. The input signal recovery of the transceiver path of combined antennas made by the MathCad code and the experimental one were compared. The reconstruction took place according to the frequency and phase responses of the transceiver path of these antennas.