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Introduction: Clinical and radiological parameters might not be sufficient to diagnose the aetiology of exudative pleural effusions accurately. Often, thoracoscopy serve as an important added tool in the correct diagnosis. Aim: To analyse the diagnostic accuracy of initial diagnosis (clinical and radiological) compared with thoracoscopic biopsy. Materials and Methods: This was the retrospective study done on all the consecutive medical thoracoscopic procedures conducted in tertiary care centre (pulmonology wing), Trivandrum, India from May 2010 to April 2016. All thoracoscopic procedures were conducted in adult patients above the age of 18 years. Kappa statistics was performed to find the diagnostic accuracy. Results: During this period, 94 diagnostic medical thoracoscopic procedures were performed. Majority of them were males (68.1%) and mean age was 54.8±13.53 years. Main diagnostic indications were undiagnosed exudative effusions (85.4%) and emphysema (7.1%). Tuberculosis was the most common initial diagnosis prior to the procedure (70.2%). Histopathology reports showed tuberculosis as the most common final diagnosis (45.7%), followed by malignancy (38%) and chronic inflammation (6.4%). Four patients who were not biopsied were excluded from diagnostic accuracy analysis. When thoracoscopic biopsy was taken as the gold standard, sensitivity was found to be 67.4% for initial diagnosis of tuberculosis and only 13.9% for malignancy. But specificity was found to be more for malignancy (81.5%) than tuberculosis (27.7%). Overall diagnostic accuracy of initial diagnosis was found to be 46.7% for tuberculosis and 54.4% for malignancy. There was minimal or no correlation (R=-0.173) between the diagnostic outcome and type of anaesthesia (local or general anaesthesia). There was no significant difference in occurrence of complications between local and general anaesthesia (p-value=0.717). Conclusion: Medical thoracoscopy had an important additional diagnostic value in management of pleural diseases as evidenced by slight agreement between initial and final diagnosis.

Renewable energy‐based energy conversion technologies have become more relevant due to environmental considerations even though they are intermittent in nature. As a result, the concept of microgrid and microgrid control techniques have been evolved as major areas of power system research. Among different inverter control methods, the droop‐based control method is more popular in microgrid systems due to its simplicity and non‐requirement of expensive communication systems. The transient performance, power‐sharing accuracy and decoupling between real and reactive power are improved by modifying the natural droop control method. In this study, the selected microgrid system consists of two inverters operating in parallel, two interconnecting lines and three loads. A state‐space model of the microgrid is created based on the small‐signal stability and the transient response is improved by introducing virtual impedance and dynamic droop gains. The different controller parameters are optimised using particle swarm optimisation ensuring stability. Eigenvalue analysis is done to analyse stability. The analysis of the response of the system for various disturbances validates the effectiveness of the proposed controller. The strategy developed ensures improved power‐sharing capability with high values of natural droop gains without compromising stability by using optimised dynamic droop gains. [ABSTRACT FROM AUTHOR]

Droop control is commonly used for controlling the power flow in microgrids dominated by inverters as it is simple and does not require any communication interface among inverters. Dynamic droop gains are incorporated along with conventional droop gains to improve the dynamic performance of the system without affecting the stability and regulation. The small signal model, which is linearized around an operating point is not sufficient to analyze the response of the droop-controlled system when large disturbances occur. The droop gains play a significant role in rejecting such large disturbances and this has not been investigated adequately. In this correspondence, a nonlinear model is developed for a dynamic droop controlled microgrid system where the emphasis is laid on the effects of dynamic droop gains on disturbance rejection. To achieve this, a Lyapunov based stability analysis is performed to estimate the domain of attraction for the dynamic controlled microgrid system by using Takagi-Sugeno method. In addition, a comparison with conventional droop-controlled method is also performed to illustrate the relative efficacy of the two droop gain methods in rejecting large disturbances. 1 Development of a nonlinear model for conventional and dynamic droop controlled microgrid system. 2 Estimation of Domain of attraction (DOA) for conventional and dynamic droop controlled microgrid system. 3 Analysis of the variation of DOA due to the variation in conventional and dynamic droop gains. [ABSTRACT FROM AUTHOR]