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This article contains a continuous-time optimal and adaptive control scheme for underwater vehicles moving in six degrees of freedom. The control scheme is an extension of the algorithm in Johansson (1990). The algorithm is optimal in the sense that it minimizes the state errors and the forces which contributes to the vehicle’s kinetic energy that is spend to correct these errors. The performance
To further clarify the mechanisms maintaining chronic atrial fibrillation (CAF). a method for system identification of activation patterns of the atria was developed. Data were obtained as repeated recordings of 8 s duration, each of 56 atrial bipolar electrograms, simultaneously acquired during open-heart surgery at multiple sites in the right atrial free wall in 12 patients with stable sinus rhy
This paper presents theory for extension of the Yakubovich-Kalman-Popov (YKP) lemma for stability analysis relevant for observer-based feedback control systems. We show that minimality is not necessary for existence of Lur'e-Lyapunov functions. Implications for output feedback stabilization, positivity, factorization and passivity are given.
OBJECTIVE: Low-level viraemia (LLV) occurs in some people with HIV (PWH) receiving antiretroviral therapy (ART) and has been linked to inferior treatment outcomes. We investigated factors associated with LLV in a nationwide cohort of Swedish PWH starting ART.METHODS: Participants were identified from the InfCareHIV register, with the following inclusion criteria: ART initiation 2006-2017, age >15
Today most industrial robot systems use dedicated and rather limited sensors, and available control systems provide limited support for feedback control. Aiming towards more autonomous robot systems, we want to improve flexibility. The game Scrabble is used as a test problem capturing these aspects. Our approach is to incorporate visual servoing and a conventional powerful off-line prograrnrning (
Homogeneous Charge Compression Ignition (HCCI) is a promising but challenging combustion engine concept. The potential for good fuel economy and low emissions is high but the transient performance required for automotive applications presents a few problems still to be solved. The focus of this work is identification of the process dynamics. An ARX type model is fitted to input-output data. A meth
The General Data Protection Regulation (GDPR) establishes a right for individuals to get access to information about automated decision-making based on their personal data. However, the application of this right comes with caveats. This paper investigates how European insurance companies have navigated these obstacles. By recruiting volunteering insurance customers, requests for information about
We study an image-based visual servoing system implemented on a non-dedicated network with non-deterministic computational nodes. A problem is that time delays are typically non-deterministic and variable and may cause significant degradation of control system performance, stability and robustness if not compensated for. Another problem is the presence of noise due to information loss and measurem
This paper presents theory for stability analysis and design for a class of observer-based feedback control systems. Relaxation of the controllability and observability conditions imposed in the Yakubovich-Kalman-Popov (YKP) lemma can be made for a class of nonlinear systems described by a linear time-invariant system (LTI) with a feedback-connected cone-bounded nonlinear element. It is shown how
Homogeneous Charge Compression Ignition (HCCI) combustion lacks direct ignition timing control, instead the auto ignition depends on the operating condition. Since auto ignition of a homogeneous mixture is very sensitive to operating condition a fast combustion timing control is necessary for reliable operation, the ignition timing control design requiring appropriate models and system output vari
The paper suggests a method for compensating the impact of friction for the control nonlinear systems, where the original controller (derived without taking into account friction) results from the passivity relation. The illustrative example is given.
System identification of continuous-time model based on discrete-time data can be performed using a algorithm combining linear regression and LQG-balanced model reduction. The approach is applicable also to unstable system dynamics and it provides balanced models for optimal linear prediction and control.
Asthma and rhinitis often co-exist in the same patient. Although some authors observed a higher prevalence and/or greater severity of asthma in patients with rhinitis, this view is not homogeneous and the debate continues. The aim of our study is to describe the prevalence of rhinitis in children and adolescents and to analyse their relationship with the prevalence of asthma. A multicentre study w
Polygenic risk scores (PRS) for prostate cancer incidence have been proposed to optimize prostate cancer screening. Prediction of lethal prostate cancer is key to any stratified screening program to avoid excessive overdiagnosis. Herein, PRS for incident prostate cancer was evaluated in two population-based cohorts of unscreened middle-aged men linked to cancer and death registries: the Västerbott
Background: Some degree of spontaneous recovery is usually observed after stroke. Experimental studies have provided information about molecular mechanisms underlying this recovery. However, the majority of pre-clinical stroke studies are performed in male rodents, and females are not well studied. This is a clear discrepancy when considering the clinical situation. Thus, it is important to includ
This paper presents theory, algorithms and validation results for system identification of continuous-time state-space models from finite non-uniformly sampled input-output sequences. The algorithms developed are methods of model identification and stochastic realization adapted to the continuous-time model context using non-uniformly sampled input-output data. The resulting model can be decompose
This study explores how democracy—often understood as an abstract concept or a location- transcending, intangible phenomenon—is produced, shaped and continuously reshaped through local library practices in certain places and under local conditions at a specific point in time. To better understand potential conflicts and/or tensions that might arise between the three levels of Swedish library polic
