Comparison of the CAF-DF and sage algorithms in multipath channel parameter estimation

In this paper, performance of the recently proposed Cross Ambiguity Function - Direction Finding (CAF-DF) technique is compared with the Space Alternating Generalized Expectation Maximization (SAGE) technique. The CAF-DF, iteratively estimates direction of arrival (DOA), time-delay, Doppler shift and amplitude corresponding to each impinging signal onto an antenna array by utilizing the cross ambiguity function. On synthetic signals, based on Monte Carlo trials, performances of the algoritms are tested in terms of root Mean Squared Error (rMSE) at different Signal-to-Noise Ratios (SNR). Cramer-Rao lower bound is included for statistical comparisons. Simulation results indicate the superior performance of the CAF-DF technique over SAGE technique for low and medium SNR values. © 2008 IEEE

Particle swarm optimization based channel identification in cross-ambiguity domain

In this paper, a new array signal processing technique by using particle swarm optimization (PSO) is proposed to identify multipath channel parameters. The proposed technique provides estimates to the channel parameters by finding a global minimum of an optimization problem. Since the optimization problem is formulated in the cross-ambiguity function (CAF) domain of the transmitted signal and the received array outputs, the proposed technique is called as PSO-CAF. The performance of the PSO-CAF is compared with the space alternating generalized expectation maximization (SAGE) technique and with another recently proposed PSO based technique for various SNR values. Simulation results indicate the superior performance of the PSO-CAF technique over mentioned techniques for all SNR values. ©2010 IEEE

Enhancements to threshold based range estimation for ultra-wideband systems

Ultra-wideband (UWB) signals have very high time resolution, which makes them a very good candidate for range estimation based wireless positioning. Although the accuracy is the major concern for range estimation, it is also important to have low-complexity algorithms that can be employed in real time. In this study, two low-complexity range estimation algorithms are proposed for UWB signals, which achieve improved performance compared to the state-of-the-art low-complexity ranging algorithms. The proposed algorithms are inspired from two well-known algorithms; 'serial backward search' (SBS) and 'jump back and search forward' (JBSF). Performances of the proposed algorithms are compared with those of the SBS and JBSF algorithms based on real measurements. In addition, theoretical bounds are calculated in order to quantify the statistical performance of the algorithms. © 2014 IEEE

Multiperson tracking with a network of ultrawideband radar sensors based on gaussian mixture PHD filters

In this paper, we investigate the use of Gaussian mixture probability hypothesis density filters for multiple person tracking using ultrawideband (UWB) radar sensors in an indoor environment. An experimental setup consisting of a network of UWB radar sensors and a computer is designed, and a new detection algorithm is proposed. The results of this experimental proof-of-concept study show that it is possible to accurately track multiple targets using a UWB radar sensor network in indoor environments based on the proposed approach. © 2014 IEEE

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Radar micro-doppler parameter estimation of human motion using particle filters Parcacik suzgeci̇ kullanilarak i̇nsan yürüyüş ü radar mi̇kro-doppler parametreleri̇ni̇n kesti̇ rilmesi̇

Guvenlikli b ¨ olgeler c¸evresinde olabilecek insan hareketlerinin tespit ¨ edilip izlenmesi guvenlik ve g ¨ ozetleme uygulamalarının c ¨ ¸ok onemli ¨ bir parc¸asını olus¸turur. ˙Insan vucudu hareket halinde iken, ¨ radar sinyallerinin vucudun de ¨ gis¸ik kısımlarından yansıması sonucu ˘ zaman-frekans duzleminde karakteristik mikro-Doppler ¨ oznitelikleri ¨ olus¸ur. Bu oznitelikler, birles¸ik zaman-frekans analizleri kul- ¨ lanılarak etkili bir s¸ekilde sec¸ilip c¸ıkarılabilinir. Bu makalede, insan hedefin konum ve mikro-Doppler parametrelerinin parc¸acık suzgeci ¨ kullanılarak (PF) es¸zamanlı bir s¸ekilde izlenmesi anlatılacaktır. Bu tip uygulamalar ic¸in ozel gelis¸tirilmis¸ ¨ 77 GHz frekansında c¸alıs¸an bir radarın verileri kullanılarak elde edilen sonuc¸lar insan konum ve hareketini karakterize eden parametrelerin izlenmesinde parc¸acık suzgec¸inin bas¸arılı bir s¸ekilde kullanımı sunulmus¸turHuman activity monitoring and tracking around restricted areas is a very crucial issue in surveillance applications. The specific motion of different parts of the human body generates unique micro-Doppler features which can be extracted effectively using joint time-frequency analysis. In this paper, we describe the simultaneous tracking of both location and radar micro-Doppler signatures of a human target using particle filtering (PF). The results obtained using the data from a specifically developed radar for these kind of applications operating at 77 GHz frequency, prove the successful usage of particle filters in tracking micro-Doppler features of the human gait