TOA-based indoor localization and tracking with inaccurate floor plan map via MRMSC-PHD filter

This paper proposes a novel indoor localization scheme to jointly track a mobile device (MD) and update an inaccurate floor plan map using the time-of-arrival measured at multiple reference devices (RDs). By modeling the floor plan map as a collection of map features, the map and MD position can be jointly estimated via a multi-RD single-cluster probability hypothesis density (MSC-PHD) filter. Conventional MSC-PHD filters assume that each map feature generates at most one measurement for each RD. If single reflections of the detected signal are considered as measurements generated by map features, then higher-order reflections, which also carry information on the MD and map features, must be treated as clutter. The proposed scheme incorporates multiple reflections by treating them as virtual single reflections reflected from inaccurate map features and traces them to the corresponding virtual RDs (VRDs), referred to as a multi-reflection-incorporating MSC-PHD (MRMSC-PHD) filter. The complexity of using multiple reflection paths arises from the inaccuracy of the VRD location due to inaccuracy in the map features. Numerical results show that these multiple reflection paths can be modeled statistically as a Gaussian distribution. A computationally tractable implementation combining a new greedy partitioning scheme and a particle-Gaussian mixture filter is presented. A novel mapping error metric is then proposed to evaluate the estimated map's accuracy for plane surfaces. Simulation and experimental results show that our proposed MRMSC-PHD filter outperforms the existing MSC-PHD filters by up to 95% in terms of average localization and by up to 90% in terms of mapping accuracy

An Indoor Localization and Tracking System Using Successive Weighted RSS Projection

This letter proposes a novel successive weighted received signal strength (RSS) indoor localization and tracking system that projects previous time instance estimated mobile device (MD) position to provide projected RSS values. Such RSS projection increases the number of available RSS from Nm to Nm + N AP , where N AP is the total number of access points and Nm is the number of RSS values measured by MD, ranging from 0 to N AP . Our proposed system thus resolves the issues associated with insufficient or no RSS values received by MD. Inertial navigation system (INS) is merged with RSS localization system to provide a weighted fusion of projected and measured RSS values. The weighting factors are derived based on the INS and RSS localization accuracy where the former is initially accurate but deteriorates with time and the latter is time-independent but environment-dependent. The proposed system was tested in indoor environments and outperformed other existing localization systems such as RSS and INS fusion using extended Kalman filter and non-line-of-sight (NLOS) selection scheme, especially in heavy multipath environment, by 42% and 75%, respectively

Localization in GPS denied environment

No abstract available

Cutaneous leukocytoclastic vasculitis due to anti-tuberculosis medications, rifampin and pyrazinamide

Anti-tuberculosis drugs frequently result in cutaneous adverse reactions, including pruritus, maculopapular exanthems, and urticaria. However, anti-tuberculosis drug-associated cutaneous leukocytoclastic vasculitis (CLV) has been rarely reported. We describe a case of CLV induced by rifampin and pyrazinamide. A 38-year-old male had been diagnosed with pulmonary tuberculosis two months ago and then he started standard anti-tuberculosis therapy with isoniazid, rifampin, ethambutol, and pyrazinamide. Purpuric lesions developed in the extremities after 1.5 months of anti-tuberculosis medication; the lesions progressively spread over the entire body. Histopathology of the purpuric skin lesion was consistent with leukocytoclastic vasculitis. The skin lesion improved after cessation of anti-tuberculosis medications and treatment with oral corticosteroids and antihistamines. Anti-tuberculosis drugs were rechallenged one at a time over 3 days. Purpura recurred on the right forearm and forehead after taking 300 mg of rifampin. The skin lesion disappeared after taking oral prednisolone. Finally, 1,500 mg of pyrazinamide was readministrated, and then purpuric lesions recurred on both forearms. This report describes a case of leukocytoclastic vasculitis secondary to rifampin and pyrazinamide therapy

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

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

Abstract 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

Modelling and measurements for an indoor microcellular communication system

This project contains the formulation of theoretical models and the results of experimental studies for the problem of microwave propagation and scattering in indoor microcellular environments.RG 15/9

Propagation models and measurements for microcellular communication systems

This thesis contains the formulation of theoretical models and the results of experimental studies for the problem of microwave propagation and scattering in microcellular communications systems for urban areas and for indoor scenes. In an urban environment, a quasi-three-dimensional vector propagation model based on the uniform theory of diffraction (UTD) has been developed, using multiple-image theory and a ray launching technique to describe the multiple reflections and diffractions. The model is applicable to a general street scene with various distributions of streets, buildings with complex geometries such as empty squares, re-entrant building geometries, angled streets with wedge-shaped corners at the junctions, rounded building corners, open areas etc.Doctor of Philosophy (EEE

Non-line-of-sight localization in multipath environments

This paper presents a comprehensive Non Line of Sight (NLOS) localization scheme and a least square estimator that leverages on the bi-directional estimation of the Angle of Arrival (AOA) and Time of Arrival (TOA) of signals exchanged between mobile and reference devices. The proposed localization scheme requires two or more signal paths which can be either Line of Sight (LOS) signals or Non-line of Sight (NLOS) multipath signals that undergo one bound scattering. Our multipath selection scheme is shown to be able to discard multiple bound scattering paths with a high degree accuracy. We used empirical data obtained through experimentation in a real environment to analyse the performance of our proposed localization scheme, and to compare it to the existing methods. The results of this experiment show that the proposed localization scheme that just uses two signal paths, is able to outperform the existing localization schemes in both LOS and extreme NLOS situations where all reference devices are in NLOS with the mobile device. This localization approach is very useful in multipath environments where it may not always be possible to have at least three reference devices in LOS with the mobile device

Inertial Navigation System Positioning Error Analysis and Cramér-Rao Lower Bound

Self-contained inertial navigation system (INS) has generated enough attention inside indoor positioning and navigation sector in recent years. However stand-alone low-cost INS suffers severe position drift after using for a short period of time due to the noises in both gyroscope and accelerometer. This paper presents the theoretical analysis of INS's position root mean squared error (RMSE) caused by white Gaussian noise within body frame sensors. Standard deviations of Gaussian noise in tri-axial accelerometer and tri-axial gyroscope are acquired through Allan Variance analysis. Up to second order of Taylor expansion is considered when approximating transformation matrix formed by gyroscope values from beginning, which is used to project acceleration collected from body frame onto local navigation frame. No particular IMU mounting position is assumed for the derivation. In addition, Cramér-Rao Lower Bound (CRLB) for INS perturbed by the same white Gaussian noise is derived for comparison with RMS error on the same route to test our proposed methodology. Monte Carlo simulation is performed to compare with derived RMS error and CRLB. The plot of RMS error is shown to be close to CRLB especially at the early stage of the route. Our proposed RMS error analysis proves to be efficient by staying close to CRLB along the route where CRLB serves as a lower benchmark of position error growth. It can also provide insight of performance for any other INS if the mean and variances of sensors noises are known. In conclusion, the main contribution of this paper is that our proposed position RMS error methodology can serve as an efficient alternative to CRLB