Time Delay Estimation in Room Acoustic Environments: An Overview

<p/> <p>Time delay estimation has been a research topic of significant practical importance in many fields (radar, sonar, seismology, geophysics, ultrasonics, hands-free communications, etc.). It is a first stage that feeds into subsequent processing blocks for identifying, localizing, and tracking radiating sources. This area has made remarkable advances in the past few decades, and is continuing to progress, with an aim to create processors that are tolerant to both noise and reverberation. This paper presents a systematic overview of the state-of-the-art of time-delay-estimation algorithms ranging from the simple cross-correlation method to the advanced blind channel identification based techniques. We discuss the pros and cons of each individual algorithm, and outline their inherent relationships. We also provide experimental results to illustrate their performance differences in room acoustic environments where reverberation and noise are commonly encountered.</p

Time of Arrival Estimation for UWB Localizers in Realistic Environments

This paper investigates time of arrival (ToA) estimation methods for ultra-wide bandwidth (UWB) propagation signals. Different algorithms are implemented in order to detect the direct path in a dense multipath environment. Different suboptimal, low-complex techniques based on peak detection are used to deal with partial overlap of signal paths. A comparison in terms of ranging accuracy, complexity, and parameters sensitivity to propagation conditions is carried out also considering a conventional technique based on threshold detection. In particular, the algorithms are tested on experimental data collected from a measurement campaign performed in a typical office building.Charles Stark Draper Laboratory (Robust Distributed Sensor Networks Program)Institute of Advanced Study (Natural Science & Technology Fellowship)Italy. Ministero dell'istruzione, dell'università e della ricerca (Virtual Immersive Communications (VICom) project)United States. Office of Naval Research (Young Investigator Award N00014- 03-1-0489)National Science Foundation (U.S.) (Grant ANI-0335256

Accuracy of circulating adiponectin for predicting gestational diabetes: a systematic review and meta-analysis

© 2016, The Author(s). Aims/hypothesis: Universal screening for gestational diabetes mellitus (GDM) has not been implemented, and this has had substantial clinical implications. Biomarker-directed targeted screening might be feasible. We sought to determine the accuracy of circulating adiponectin for early prediction of GDM. Methods: A systematic review and meta-analysis of the literature to May 2015 identified studies in which circulating adiponectin was measured prior to a diagnosis of GDM. Data on diagnostic accuracy were synthesised by bivariate mixed effects and hierarchical summary receiver operating characteristic (HSROC) models. Results: Thirteen studies met the eligibility criteria, 11 of which (2,865 women; 794 diagnosed with GDM) had extractable data. Circulating adiponectin had a pooled diagnostic odds ratio (DOR) of 6.4 (95% CI 4.1, 9.9), a summary sensitivity of 64.7% (95% CI 51.0%, 76.4%) and a specificity of 77.8% (95% CI 66.4%, 86.1%) for predicting future GDM. The AUC of the HSROC was 0.78 (95% CI 0.74, 0.81). First trimester adiponectin had a pooled sensitivity of 60.3% (95% CI 46.0%, 73.1%), a specificity of 81.3% (95% CI 71.6%, 88.3%) and a DOR of 6.6 (95% CI 3.6, 12.1). The AUC was 0.79 (95% CI 0.75, 0.82). Pooled estimates were similar after adjustment for age, BMI or specific GDM diagnostic threshold. Conclusions/interpretation: Pre-pregnancy and early pregnancy measurement of circulating adiponectin may improve the detection of women at high risk of developing GDM. Prospective evaluation of the combination of adiponectin and maternal characteristics for early identification of those who do and do not require OGTT is warranted