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• This is a qualitative systematic review focusing on the views of patients with COPD on telemedicine. • Most of patients with COPD hold a positive attitude towards telemedicine. • Themes of ease of use, usefulness, difficulty of use and uselessness were defined. There are some qualitative studies on the views of patients with chronic obstructive pulmonary disease (COPD) on telemedicine, however, there are few related qualitative systematic reviews. To systematically review and synthesize qualitative studies involving the perceptions of patients with COPD about telemedicine to understand patients' attitudes and expectations for telemedicine and determine the obstacles and stimulus in the use of telemedicine. We searched PubMed, Web of Science, MEDLINE, Embase and CINAHL for articles published from January 2000 to December 2020. The data were analysed using thematic synthesis. We included 20 articles involving 19 studies and 301 patients, and we identified four themes: perceived ease of use, perceived usefulness, perceived difficulty of use, and perceived uselessness. We found that although patients have different views on telemedicine, most of them have a positive attitude towards it. The synthesis of views will help us determine the factors that promote or hinder the application of telemedicine and guide the design and implementation of telemedicine in the future. [ABSTRACT FROM AUTHOR]

Abstract The remote state estimation problem is considered for general non-Gaussian systems. The estimator runs particle filtering algorithm to track the non-Gaussian probability density function (PDF) of the target state. We are concerned with the reduction of sensor-to-estimator communication while maintaining acceptable estimation accuracy. For this purpose, a novel event-based transmission scheme is proposed where the Kullback–Leibler divergence is used to identify informative measurements. We develop a two-step approximation procedure to obtain a parametric form for the event generator function, thereby enabling each sensor to quantify the informativeness of its current measurement without running a copy of the estimator. Furthermore, a Monte Carlo method is proposed to evaluate the likelihood function of the set-valued measurements. Simulation results demonstrate the effectiveness of our scheme, especially when the predictive PDF of the measurement is strongly non-Gaussian. [ABSTRACT FROM AUTHOR]

In this paper, the filtering problem for systems with fading measurements is considered. Taking advantage of the cascaded structure of the system, the original filtering problem is decomposed into two subproblems: 1) recovery of the original measurements from the faded ones, and 2) state estimation based on the recovered signals. A two-stage particle filtering (PF) algorithm is proposed to achieve simultaneous measurement recovery and state estimation. In our scheme, the second-stage resampling procedure can be implemented concurrently, resulting in a significant reduction of execution time. Two examples are provided to demonstrate the effectiveness of our algorithm. A benchmark problem for nonlinear filtering is tackled in the first example and, in the second example, the proposed algorithm is applied to the object tracking problem where the measured signal is distorted by the communication channel. Simulation results show that, compared with the brute force PF, the two-stage PF can strike better balance between tracking accuracy and execution time. [ABSTRACT FROM AUTHOR]

Abstract As well-known disturbance rejection methods, active disturbance rejection control and disturbance observer-based control can effectively improve the control performances of complex systems in the presence of disturbances. However, the accurate rejection of multiple disturbances for control systems of practical engineering, for example, the attitude control system of flexible spacecraft, is still a bottleneck problem. In order to further improve the anti-disturbance capability and reduce the conservativeness, this paper proposes a novel enhanced anti-disturbance control law for the attitude control system of flexible spacecraft by combining active disturbance rejection control and disturbance observer-based control in a unified framework. More specifically, the disturbance from flexible vibration is described by an uncertain exogenous system based on the partially known information including elastic damping ratios and modal frequencies. The disturbance observer-based control is utilized to estimate and thereby reject this disturbance. On the other hand, the other disturbances such as external environmental disturbance and complex model nonlinearity are merged into a equivalent disturbance with bounded derivative, which is compensated by using the active disturbance rejection control law. Stability and robustness analysis are carried out for the disturbance observer and extended state observer. Finally, simulation results of low-earth-orbit flexible satellite are presented to verify the effectiveness of proposed methods. [ABSTRACT FROM AUTHOR]