Relaxed Control Research Articles

Relaxed optimal control problem for a finite horizon G-SDE with delay and its application in economics

This paper investigates the existence of a G-relaxed optimal control of a controlled stochastic differential delay equation driven by G-Brownian motion (G-SDDE in short). First, we show that optimal control of G-SDDE exists for the finite horizon case. We present as an application of our result an economic model, which is represented by a G-SDDE, where we studied the optimisation of this model. We connected the corresponding Hamilton–Jacobi–Bellman equation of our controlled system to a decoupled G-forward backward stochastic differential delay equation (G-FBSDDE in short). Finally, we simulate this G-FBSDDE to get the optimal strategy and cost.

Can a mindfulness programme in schools for students with ADHD symptoms improve emotional well-being?

Abstract Background This study employs a cluster randomized controlled trial to investigate the effectiveness of a universal mindfulness-based intervention (MBI) in classrooms in improving emotional well-being and emotion regulation among adolescents with elevated ADHD symptoms. Methods The study comprised 342 students: 164 in an MBI group, 128 in a relaxation control group, and 47 in an inactive control group. Positive and negative emotional states and the emotion regulation strategies of rumination, acceptance, catastrophizing, positive reappraisal, and self-kindness were measured at the pre- (T0) and post-intervention (T9) and the 26-week follow-up (T26). Linear mixed models were used to analyze the intervention effects among all participants and separately by gender and ADHD symptom type. Results The results showed that compared to the controls, there was a beneficial effect on the MBI group concerning acceptance at T9; acceptance remained at the baseline level in the MBI group but decreased in the inactive control group. In contrast, in the inactive control group, rumination decreased at T9, and positive reappraisal increased at T26 compared to the MBI group. The MBI had no detectable effects on self-kindness, catastrophizing, or positive/negative emotional states. Findings on the emotion regulation strategies varied by gender. In boys, the MBI increased acceptance at T9 compared to the inactive control group, whereas in girls, the programme reduced catastrophizing at T9 and T26 compared to the active control group. Contrary in boys, MBI group exhibited less reduction in catastrophizing at T9 compared to the inactive control group. Conclusions Universal MBIs may have some beneficial effects on emotion regulation in adolescents with elevated ADHD symptoms. Both girls and boys might be responsive to universal MBIs as part of the school curriculum, however not all consequences are positive (especially in boys). Key messages • Universal MBIs in classrooms may have some beneficial effects on emotion regulation among adolescent with elevated ADHD symptoms; however, the results are contradictory and more research is needed. • Even though, universal MBIs may have some benefits, they may require modifications to lead to more beneficial effects on emotional well-being when used with this subgroup of students.

Does mindfulness program reduce stress and enhance self-kindness in schools? Healthy Learning Mind

Abstract Introduction There is a scarcity of research with high quality methods on the effectiveness of mindfulness-based interventions (MBIs) on adolescents’ mental well-being. This study investigates the MBI effects on adolescents’ stress and self-kindness with an extensive cluster RCT design, and a role of self-kindness as a mediator for the association between the MBI and stress. Additionally, the study explores how age, gender, and an independent mindfulness practice moderate the effects on the outcomes. Methods Participants (Finnish students, aged 12-15 years) were randomized to a MBI group (N = 1646), an active relaxation control group (N = 1488), and an inactive control group (N = 385). The outcomes were measured at the baseline (T0), at 9-week post-intervention (T9), and at 26-weeks follow-up (T26). Results Overall, the MBI was more effective in stress reduction when compared to the active control at T9 (β = -0.04, p < 0.01, d = -0.11) and T26 (β = -0.04, p = 0.02, d = -0.11). Furthermore, students in the MBI group who carried out their regular mindfulness home practice showed greater decrease of stress. There were no MBI effects on self-kindness, nor did a change of self-kindness mediate the effects of MBI on stress. Discussion These findings demonstrate that the 9-week MBI is slightly more effective to reduce stress relative to relaxation training. Key messages • The result highlight the potential of MBI in increasing the stress management among students in school context. • To ensure the effectiveness of MBIs in school context we need to teach these skills to teacher students already during their basic education in educational institutions and universities.

Risk of Infection in Older Adults With Type 2 Diabetes With Relaxed Glycemic Control.

To compare the risk of hospitalization for infection among patients who achieve intensive versus relaxed glycemic control. This retrospective cohort study included adults age ≥65 years with type 2 diabetes from an integrated health care delivery system. Negative binomial models were used to estimate incidence rates and relative risk (RR) of hospitalization for infections (respiratory; genitourinary; skin, soft tissue, and bone; and sepsis), comparing two levels of relaxed (hemoglobin A1c [HbA1c] 7% to <8% and 8% to <9%) with intensive (HbA1c 6% to <7%) glycemic control from 1 January 2019 to 1 March 2020. Among 103,242 older patients (48.5% with HbA1c 6% to <7%, 35.3% with HbA1c 7% to <8%, and 16.1% with HbA1c 8% to <9%), the rate of hospitalization for infections was 51.3 per 1,000 person-years. Compared with HbA1c 6% to <7%, unadjusted risk of hospitalization for infections was significantly elevated among patients with HbA1c 8% to <9% (RR 1.25; 95% CI 1.13, 1.39) but not among patients with HbA1c 7% to <8% (RR 0.99; 95% CI 0.91, 1.08), and the difference became nonsignificant after adjustment. Across categories of infections, the adjusted RR of hospitalization was significantly higher among patients with HbA1c 8% to <9% only for skin, soft tissue, and bone infection (RR 1.33; 95% CI 1.05, 1.69). Older patients with type 2 diabetes who achieve relaxed glycemic control levels endorsed by clinical guidelines are not at significantly increased risk of hospitalization for most infections, but HbA1c 8% to <9% is associated with an increased risk of hospitalization for skin, soft tissue, and bone infections.

On optimal control of coupled mean-field forward-backward stochastic equations

Abstract We consider a control problem for a mean-field coupled forward-backward stochastic differential equations, called also McKean–Vlasov equation (MF-FBSDE). For this type of equations, the coefficients depend not only on the state of the system, but also on its marginal distributions. They arise naturally in mean-field control problems and mean-field games. We consider the relaxed control problem where admissible controls are measure-valued processes. We prove the existence of a relaxed optimal control by using a suitable form of Skorokhod representation theorem and Jakubowski’s topology, on the space of càdlàg functions. We use martingale measure to define the relaxed state process. Our results extend to MF-FBSDEs those already known for forward and backward stochastic equations of Itô type.

Comparative analysis of hospital-acquired and community-acquired infections at a tertiary hospital in China before and during COVID-19: A 7-year longitudinal study (2017-2023)

This 7-year longitudinal survey (2017-2023) assessed the point prevalence of hospital-acquired infections (HAIs) and community-acquired infections (CAIs) at a first-class tertiary hospital in China, both prior to and during the Corona Virus Disease 2019 (COVID-19) pandemic. Patients were stratified into prepandemic and pandemic periods, as well as into stringent and relaxed infection prevention and control (IPC) phases, to compare the point prevalence of HAIs and CAIs. The overall point prevalence of HAIs was 1.50% (95% confidence interval [CI], 1.32%-1.71%), showing a significant downward trend (P=.021). Among patients receiving pathogen testing, the point prevalence of HAIs significantly declined during the pandemic (6.26% vs9.89%, P<.001). The point prevalence of CAIs demonstrated a notable increase in 2023 compared with 2020 to 2022 among pathogen-tested patients (81.37% vs74.18%, P=.001). Multivariate analysis identified hospitalization during the pandemic as a protective factor against HAIs (adjusted odds ratio 0.49, 95% CI, 0.36-0.67). The comprehensive IPC strategy implemented during the COVID-19 pandemic at this tertiary hospital significantly reduced the point prevalence of HAIs. However, CAIs exhibited a rising trend following the relaxation of COVID-19 IPC measures.

Relaxed Control Barrier Function Based Control for Closest Approach by Underactuated USVs

Relaxed Control Barrier Function Based Control for Closest Approach by Underactuated USVs

Potassium Supplementation and Prevention of Atrial Fibrillation After Cardiac Surgery

Supplementing potassium in an effort to maintain high-normal serum concentrations is a widespread strategy used to prevent atrial fibrillation after cardiac surgery (AFACS), but is not evidence-based, carries risks, and is costly. To determine whether a lower serum potassium concentration trigger for supplementation is noninferior to a high-normal trigger. This open-label, noninferiority, randomized clinical trial was conducted at 23 cardiac surgical centers in the United Kingdom and Germany. Between October 20, 2020, and November 16, 2023, patients with no history of atrial dysrhythmias scheduled for isolated coronary artery bypass grafting (CABG) surgery were enrolled. The last study patient was discharged from the hospital on December 11, 2023. Patients were randomly assigned to a strategy of tight or relaxed potassium control (only supplementing if serum potassium concentration fell below 4.5 mEq/L or 3.6 mEq/L, respectively). Patients wore an ambulatory heart rhythm monitor, which was analyzed by a core laboratory masked to treatment assignment. The prespecified primary end point was clinically detected and electrocardiographically confirmed new-onset AFACS in the first 120 hours after CABG surgery or until hospital discharge, whichever occurred first. All primary outcome events were validated by an event validation committee, which was masked to treatment assignment. Noninferiority of relaxed potassium control was defined as a risk difference for new-onset AFACS with associated upper bound of a 1-sided 97.5% CI of less than 10%. Secondary outcomes included other heart rhythm-related events, clinical outcomes, and cost related to the intervention. A total of 1690 patients (mean age, 65 years; 256 [15%] females) were randomized. The primary end point occurred in 26.2% of patients (n = 219) in the tight group and 27.8% of patients (n = 231) in the relaxed group, which is a risk difference of 1.7% (95% CI, -2.6% to 5.9%). There was no difference between the groups in the incidence of at least 1 AFACS episode detected by any means or by ambulatory heart rhythm monitor alone, non-AFACS dysrhythmias, in-patient mortality, or length of stay. Per-patient cost for purchasing and administering potassium was significantly lower in the relaxed group (mean difference, $111.89 [95% CI, $103.60-$120.19]; P <.001). For AFACS prophylaxis, supplementation only when serum potassium concentration fell below 3.6 mEq/L was noninferior to the current widespread practice of supplementing potassium to maintain a serum potassium concentration greater than or equal to 4.5 mEq/L. The lower threshold of supplementation was not associated with any increase in dysrhythmias or adverse clinical outcomes. ClinicalTrials.gov Identifier: NCT04053816.

On Borkar and Young Relaxed Control Topologies and Continuous Dependence of Invariant Measures on Control Policy

On Borkar and Young Relaxed Control Topologies and Continuous Dependence of Invariant Measures on Control Policy

Relaxed Model Predictive Control of T-S Fuzzy Systems via a New Switching-Type Homogeneous Polynomial Technique

Relaxed Model Predictive Control of T-S Fuzzy Systems via a New Switching-Type Homogeneous Polynomial Technique

Optimal Relaxed Control for a Decoupled G-FBSDE

In this paper we study a system of decoupled forward-backward stochastic differential equations driven by a G-Brownian motion (G-FBSDEs) with non-degenerate diffusion. Our objective is to establish the existence of a relaxed optimal control for a non-smooth stochastic optimal control problem. The latter is given in terms of a decoupled G-FBSDE. The cost functional is the solution of the backward stochastic differential equation at the initial time. The key idea to establish existence of a relaxed optimal control is to replace the original control problem by a suitably regularised problem with mollified coefficients, prove the existence of a relaxed control, and then pass to the limit.

Relaxed static output feedback control for discrete-time Takagi-Sugeno fuzzy systems: A switching sequence convex optimization algorithm

In this paper, a new switching sequence convex optimization (SSCO) algorithm is proposed for solving non-convex optimization problem with complex time-varying relaxation matrix structures that arises during output feedback design. Firstly, the introduced time-varying relaxation matrix combines the membership functions and the designed switching mechanism to adjust the positive and negative terms of the inequality constraints. As a result, relaxed controller design conditions with complex matrix structures are established. The proposed SSCO algorithm employs switching optimization variables and inner approximation strategy, which is able to compute non-convex optimization problems with complex matrix structures more flexibly and converge quickly. It is worth noting that the implementation of the SSCO algorithm requires a set of strictly feasible initial solutions. Therefore, an initialization iterative algorithm is proposed, which overcomes the difficulties of transforming the solving problem into a typical non-convex optimization problem and linearizing multiple different concave parts, by which a set of optimized feasible solutions are obtained. Finally, simulation examples are used to demonstrate the superiority of the design scheme proposed in this paper.

Phase-space analysis of a two-section InP laser as an all-optical spiking neuron: dependency on control and design parameters

Using a rate-equation model we numerically evaluate the carrier concentration and photon number in an integrated two-section semiconductor laser, and analyse its dynamics in three-dimensional phase space. The simulation comprises compact model descriptions extracted from a commercially-available generic InP technology platform, allowing us to model an applied reverse-bias voltage to the saturable absorber. We use the model to study the influence of the injected gain current, reverse-bias voltage, and cavity mirror reflectivity on the excitable operation state, which is the operation mode desired for the laser to act as an all-optical integrated neuron. We show in phase-space that our model is capable of demonstrating four different operation modes, i.e. cw, self-pulsating and an on-set and excitable mode under optical pulse injection. In addition, we show that lowering the reflectivity of one of the cavity mirrors greatly enhances the control parameter space for excitable operation, enabling more relaxed operation parameter control and lower power consumption of an integrated two-section laser neuron.

Humans do not avoid reactively implementing cognitive control.

The ability to exert cognitive control allows us to achieve goals in the face of distraction and competing actions. However, control is costly-people generally aim to minimize its demands. Because control takes many forms, it is important to understand whether such costs apply universally. Specifically, reactive control, which is recruited in response to stimulus or contextual features, is theorized to be deployed automatically, and not depend on attentional resources. Here, we investigated whether people avoided implementing reactive control in three experiments. In all, participants performed a Stroop task in which certain items were mostly incongruent (MI), that is, associated with a high likelihood of conflict (triggering a focused control setting). Other items were mostly congruent, that is, associated with a low likelihood of conflict (triggering a relaxed control setting). Experiment 1 demonstrated that these control settings transfer to a subsequent unbiased transfer phase. In Experiments 2-3, we used a demand selection task to investigate whether people would avoid choice options that yielded items that were previously MI. In all, participants continued to retrieve focused control settings for previously MI items, but they did not avoid them in the demand selection task. Critically, we only found demand avoidance when there was an objective difference in demand between options. These findings are consistent with the idea that implementing reactive control does not register as costly. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The Effect of Auricular Acupressure on Uterine Contractions, Fetal Heart Rate, and Length of Labor in the Active Phase of Primigravida

The still high maternal mortality rate (MMR) in Indonesia, especially in East Java, is caused by indirect causes or other causes such as prolonged labor, so a method is needed to treat cases of prolonged labor such as auricular acupressure. Auricular acupressure (AKAR) is a non-pharmacological method proven effective for uterine contractions, but its side effects on the fetal heart rate (FHR) are unknown. The research aimed to analyze the AKAR method on uterine contractions, FHR, and labor duration in the first stage's active phase. This type of research is truly experimental, with a pretest-posttest control group design. The research subjects were 41 respondents, primigravida active phase first-stage mothers, selected by consecutive sampling and randomly divided into two groups, namely 21 AKAR groups and 20 deep breathing relaxation control groups. The research results of the Friedman test statistical test ρ-value equal 0.000 in the AKAR group and ρ-value equal 0.000 in the control group, meaning that AKAR influences uterine contractions. The Friedman Test findings show that AKAR does not affect FHR (ρ-value equal 0.618). The Independent Sample Test ρ-value equal 0.29 indicates no statistically significant difference between the two groups' labor lengths throughout the first stage's active phase. The AKAR group's average labor time in the first stage of the active phase was 365.40 minutes, with a minimum of 267 minutes and a high of 395 minutes. Conclusion: The auricular acupressure method affects uterine contractions but does not affect the fetal heart rate. There was no difference in the length of labor in the first active phase of labor between the auricular acupressure and deep breathing relaxation groups, so it is recommended that the auricular acupressure method can be used as an alternative complementary care to prevent prolonged labor.

Long-term follow-up of TREK-1 KO mice reveals the development of bladder hypertrophy and impaired bladder smooth muscle contractility with age.

Stretch-activated two-pore domain K+ (K2P) channels play important roles in many visceral organs, including the urinary bladder. The TWIK-related K+ channel TREK-1 is the predominantly expressed K2P channel in the urinary bladder of humans and rodents. Downregulation of TREK-1 channels was observed in the urinary bladder of patients with detrusor overactivity, suggesting their involvement in the pathogenesis of voiding dysfunction. This study aimed to characterize the long-term effects of TREK-1 on bladder function with global and smooth muscle-specific TREK-1 knockout (KO) mice. Bladder morphology, bladder smooth muscle (BSM) contractility, and voiding patterns were evaluated up to 12 mo of age. Both sexes were included in this study to probe the potential sex differences. Smooth muscle-specific TREK-1 KO mice were used to distinguish the effects of TREK-1 downregulation in BSM from the neural pathways involved in the control of bladder contraction and relaxation. TREK-1 KO mice developed enlarged urinary bladders (by 60.0% for males and by 45.1% for females at 6 mo; P < 0.001 compared with the age-matched control group) and had a significantly increased bladder capacity (by 137.7% at 12 mo; P < 0.0001) and compliance (by 73.4% at 12 mo; P < 0.0001). Bladder strips isolated from TREK-1 KO mice exhibited decreased contractility (peak force after KCl at 6 mo was 1.6 ± 0.7 N/g compared with 3.4 ± 2.0 N/g in the control group; P = 0.0005). The lack of TREK-1 channels exclusively in BSM did not replicate the bladder phenotype observed in TREK-1 KO mice, suggesting a strong neurogenic origin of TREK-1-related bladder dysfunction.NEW & NOTEWORTHY This study compared voiding function and bladder phenotypes in global and smooth muscle-specific TREK-1 KO mice. We found significant age-related changes in bladder contractility, suggesting that the lack of TREK-1 channel activity might contribute to age-related changes in bladder smooth muscle physiology.

Improved differential fault analysis of Grain128-AEAD

The number of smart devices connected to the Internet has been constantly increasing, and as a result, lightweight cryptography (LWC) has become more important in the past decade. The Lightweight Cryptography (LWC) Project is an initiative taken by the National Institute of Standards and Technology (NIST) to standardize such LWC algorithms. Grain128-AEAD, which was submitted to the NIST LWC project, is an encryption algorithm that provides both confidentiality and integrity assurance. Third-party security analysis of the submitted ciphers is an important aspect of the evaluation of the submission to the NIST LWC project. Although several pieces of existing research, such as the bit-flipping attack, random fault attack, and deterministic random fault attack, have examined the security of Grain128-AEAD, there is still room for improvement in the fault attack models of these studies. This work aims to fill this research gap by analyzing the security margin of Grain128-AEAD against a series of improved differential fault attacks. In this study, we developed a probabilistic random fault attack and applied it to Grain128-AEAD. As an improvement of the existing research, a probabilistic approach can be applied to a more relaxed moderate control attack model. The existing moderate control model assumes the fault to be injected within any bit of a given byte, whereas the faults in our improved approach can be injected within any bits of a two-byte/four-byte segment, thereby relaxing the fault precision. The results indicate that the improved moderate control requires 388 keystreams for the two-byte model and 279 for the four-byte model to identify the target fault locations for implementing a state recovery attack. The relaxed fault attack models presented in this work are more practical to implement; hence, the findings of this research have improved the existing studies and narrowed the current research gap on the fault attack models of Grain128-AEAD. % To maintain consistency in terminology, "Grain-128AEAD" has been revised to "Grain128-AEAD" in both the abstract and the main text. Please confirm this revision.

Financial institution agglomeration and corporate labor allocation efficiency—Based on the context of government debt expansion

This study investigates how financial institution agglomeration affects labor allocation efficiency in non-financial firms listed on China's A-share markets, within a context of expanded government debt and relaxed local debt financing controls. Results show that such agglomeration significantly improves labor efficiency, mainly by easing financing constraints. The positive impact is stronger in non-state-owned and manufacturing firms.

On the maximum principle for relaxed control problems of nonlinear stochastic systems

We consider optimal control problems for a system governed by a stochastic differential equation driven by a d-dimensional Brownian motion where both the drift and the diffusion coefficient are controlled. It is well known that without additional convexity conditions the strict control problem does not admit an optimal control. To overcome this difficulty, we consider the relaxed model, in which admissible controls are measure-valued processes and the relaxed state process is governed by a stochastic differential equation driven by a continuous orthogonal martingale measure. This relaxed model admits an optimal control that can be approximated by a sequence of strict controls by the so-called chattering lemma. We establish optimality necessary conditions, in terms of two adjoint processes, extending Peng’s maximum principle to relaxed control problems. We show that relaxing the drift and diffusion martingale parts directly as in deterministic control does not lead to a true relaxed model as the obtained controlled dynamics is not continuous in the control variable.

Exercise Recovery Oxygen Uptake Kinetics in Comorbid Insomnia and Obstructive Sleep Apnea

ABSTRACT Background Delayed recovery following cardiopulmonary exercise testing (CPET) is associated with cardiac morbidity and mortality. Recovery kinetics of oxygen uptake have not been described in people with comorbid obstructive sleep apnea and insomnia (COMISA) who have an increased risk of cardiovascular disease. Our objectives were to (a) describe heart rate recovery (HRR), oxygen recovery slopes (V˙O2/t), and time to half recovery of V˙O2max (T1/2) following CPET in people with COMISA; and (b) investigate their response to 8 weeks of relaxation control intervention (Relax) or exercise training (Ex) consisting of 3 weekly sessions of individualized aerobic and strength training. Methods Participants with confirmed COMISA underwent maximal exercise testing on a cycle ergometer preintervention (n = 16) and postintervention (Ex: n = 6, Relax: n = 8). HRR and V˙O2/t (at minutes 1, 2, and 5) and T1/2 were calculated during recovery following peak exercise intensity. Results At baseline, HRR at minutes 1, 2, and 5 were 20 ± 7, 35 ± 8, and 49 ± 13 b·min−1, respectively, while V˙O2/t slopes were 0.731 ± 0.521, 0.590 ± 0.288, and 0.222 ± 0.096 L·min−2, respectively. T1/2 was 97 ± 64 seconds. Large effect sizes (ESs) of time × group interaction were found for HRR 5 (ηp2 = 0.232) and V˙O2/t 1 (ηp2 = 0.215) and of group for HRR2 (ηp2 = 0.275). Conclusion These findings suggest that recovery kinetics of oxygen uptake are delayed in people with COMISA but can improve following exercise training in comparison with a relaxation control intervention. Future studies including additional comparison groups are warranted to characterize more precisely the impact of COMISA on recovery kinetics of oxygen uptake and confirm the benefits of exercise training.