This study is aimed at investigating the $H_\infty$ distributed state estimation (DSE) problem for discrete-time systems with unknown parameters subject to state and output nonlinearities over wireless sensor networks (WSNs) under the influence of energy-bounded process disturbances and sensor noise. The study involves the design of a novel distributed estimator for simultaneously estimating the state of the target plant and identifying its unknown parameters in the absence of a fusion center by employing innovations from the sensor itself and its immediate neighbors in the WSN communication topology. A new free-weighting scalar approach is presented; it comprises manipulations of the estimation error, relaxes the requirement regarding global information of connectivity, allows different gains for different estimators, provides less conservative results, and permits an independent design for sensor nodes. The Lyapunov theory and Kronecker product properties are utilized to establish the asymptotic stability of the estimation error dynamics and to satisfy the $H_\infty$ performance constraints regarding disturbance attenuation. The distributed estimator design problem is formulated as a convex optimization problem, which is solved iteratively and autonomously by each sensor node in the WSN topology. Finally, an illustrative example is provided to demonstrate the viability of the suggested estimation strategy.
This paper highlights the design of a controller established on estimated states for one-sided Lipschitz (OSL) nonlinear systems subject to output and input delays. The controller has been devised by involving Luenberger-like estimated states. The stability of the time-delayed nonlinear system is reckoned by assuming a Lyapunov functional for delayed dynamics and for which a delay-range dependent criterion is posed with a delay ranging between known upper and lower bounds. The time derivative of the functional is further exploited with linear matrix inequality (LMI) procedures, and employing Wirtinger’s inequality for the integral terms instead of the traditional and more conservative Jensen’s condition. Moreover, a sufficient and necessary solution is derived for the proposed design by involving the tedious decoupling technique to attain controller and observer gain simultaneously. The proposed methodology validates the observer error stability between observers and states asymptotically. The solution of matrix inequalities was obtained by employing cone-complementary linearization techniques to solve the tiresome constraints through simulation tools by convex optimization. Additionally, a novel scheme of an observer-based controller for the linear counterpart is also derived for one-sided Lipschitz nonlinear systems with multiple delays. Finally, the effectualness of the presented observer-based controller under input and output delays for one-sided Lipschitz nonlinear systems is validated by considering a numerical simulation of mobile systems in Cartesian coordinates.
This paper describes the attitude stabilization problem of a rigid spacecraft. We consider the stabilization problem both in absence and presence of disturbances. To obtain a better disturbance rejection property we use sliding mode controller design technique. Stabilization of rigid spacecraft is a particular type of problem that can be solved with sliding mode control. A discontinuous finite time control law is proposed in presence of disturbances by applying sliding mode method such that the states eventually converge to a small region of origin. After that the results are shown for stabilization for a particular example with specific values of parameters. Numerical simulation results show the effectiveness of the method.
Background: Stroke is one of the leading causes of death for older individuals with hypertension. This research investigates the variations in stroke mortality rates and trends among 65-year-old hypertension patients in the US from 2000 to 2020. Methods: The CDC WONDER database's mortality data from 2000 to 2020 was used for a retrospective analysis. Average Annual Percentage Change (AAPC) and Annual Percent Change (APC) were used to evaluate trends and produce age-adjusted mortality rates (AAMRs) per 100,000 people. Data was stratified by year, sex, race/ethnicity, and geographical regions. Results: Between 2000 and 2020, 598,341 deaths among individuals 65 years of age or older in the United States were related to stroke due to hypertension. Most occurred in nursing homes/long-term care facilities (36.7%). The overall AAMR for stroke in hypertension-related deaths dropped from 86.6 in 2000 to 51.8 in 2020, with an AAPC of -2.86 (95% CI: -3.18 to -2.61, p < 0.000001). Between 2000 and 2012, the AAMR had a considerable reduction (APC: -2.30, p < 0.000001). Subsequently, from 2012 to 2018, there was a more dramatic decrease (APC: -6.85, p < 0.000001) than a notable rise (APC: 6.45, p = 0.024) from 2018 to 2020. Older women had higher AAMRs than older men (women: 66.5; men: 60.1). Both sexes experienced decreases, with the decline more prominent in women (women: AAPC: -3.20, p < 0.000001; men: AAPC: -2.22, p < 0.000001). There were notable racial differences: Black people had the highest AAMRs (31.0), followed by White people (21.8), American Indians and Alaska Natives (18.6), Asians and Pacific Islanders (12.9), and Hispanics (12.5). All racial groups experienced decreases in AAMRs, most pronounced in Asians (AAPC: -4.62, p < 0.000001). Geographically, Massachusetts had the lowest (36.3), and Mississippi had the highest (117.7) AAMRs. The Western region had the highest average AAMR (71.8), while nonmetropolitan areas exhibited higher AAMRs than metropolitan areas (nonmetropolitan: 25.9; metropolitan: 20.7). Conclusion: The study uncovers significant variations in mortality rates among elderly individuals in the US due to stroke and hypertension. The recent uptick emphasizes the necessity for targeted efforts to tackle these disparities and improve the health outcomes of affected communities.
Background: Stroke in malignancy is a significant cause of mortality among older adults. This study analyzes demographic trends and disparities in mortality rates due to stroke in malignancy among adults aged 65 and older from 1999 to 2020. Methods: A retrospective analysis was conducted using CDC WONDER death certificate data from 1999 to 2020. Age-adjusted mortality rates (AAMRs) were calculated per 100,000 persons stratified by year, sex, race/ethnicity, and geographical regions. Trends were assessed using Average Annual Percentage Change (AAPC) and annual percent change (APC). Results: Between 1999 and 2020, Stroke in Malignancy resulted in 198,659 deaths among adults (≥65 years) in the United States. Fatalities occurred predominantly in medical facilities (36.5%), followed by nursing homes (29.3%), and at decedents’ homes (24.2%). The overall age-adjusted mortality rate (AAMR) for Stroke in Malignancy-related deaths decreased from 32.8 in 1999 to 16.5 in 2020, with an Average Annual Percentage Change (AAPC) of -3.35 (p-value < 0.000001). Notably, there was a significant decline in AAMR from 1999 to 2018 (APC: -4.23, p-value < 0.000001), followed by a notable increase from 2018 to 2020 (APC: 5.33, p-value = 0.025595). Both men and women showed decreased AAMRs, with men having higher rates (men: 28.1; women: 17.5). AAMRs varied among racial/ethnic groups, with Black/African Americans having the highest AAMR (31.0), followed by Whites (21.8), American/Alaska Natives (18.6), Asian/Pacific Islanders (12.9), and Hispanics (12.5). AAMRs decreased across all races, with the most significant decline observed in Asians (AAPC: -4.62, p-value < 0.000001). Geographically, AAMRs varied among states, ranging from 11.0 in Arizona to 33.7 in Mississippi. Across regions, the Midwestern region had the highest mortality (AAMR: 23.4), with nonmetropolitan areas exhibiting slightly higher AAMRs (AAMR: 25.9). Both metropolitan and nonmetropolitan regions experienced decreased AAMRs over the study period (p-value < 0.000001). Conclusion: The analysis reveals substantial demographic disparities in mortality rates attributed to Stroke in malignancy among older adults. While the overall decline in mortality rates indicates progress, the concerning upsurge in recent years necessitates proactive measures. Addressing these disparities through targeted interventions and equitable healthcare access is imperative to optimize outcomes for this at-risk population.
In this paper, the notion of sign-consensus for the Lipschitz nonlinear multi-agents over a signed graph is introduced and controller design conditions are provided for realizing consensus among signs of states of agents. The previous works on sign-consensus are limited to the linear systems only. The attainment of sign-consensus for the nonlinear multi-agent systems is a non-trivial control problem, for which Lipschitz nonlinear dynamics are reformulated using the linear parameter varying (LPV) transformation. To guarantee the sign-consensus in a network of multiple agents, fully-distributed adaptive protocol is applied using reformulated Lipschitz nonlinear dynamics, and two design conditions are provided based on the Lipschitz constant oriented and LPV-based approaches. The first approach is comparatively less computationally complex while LPV approach holds significance for developing less conservative sign-consensus control scheme. To the best of our knowledge, distributed sign consensus methods for Lipschitz systems, based on LPV formulation, have been analyzed for the first time. The proposed approach is adaptive and can be regarded as fully-distributed, as it does not require the central knowledge of graph properties. Further, results are extended for nonlinear systems undergoing disturbances and ultimate boundedness of sign-consensus error is guaranteed. Numerical simulations on groups of Chua’s circuits and mechanical oscillators are presented to validate the results.
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