Relaxed Control Research Articles

Shape‐Mediated Magnetocrystalline Anisotropy and Relaxation Controls by Cobalt Ferrite Core–Shell Heterostructures for Magnetothermal Penetration Delivery (Adv. Mater. Interfaces 12/2022)

Shape‐Mediated Magnetocrystalline Anisotropy and Relaxation Controls by Cobalt Ferrite Core–Shell Heterostructures for Magnetothermal Penetration Delivery (Adv. Mater. Interfaces 12/2022)

Mean-field Markov decision processes with common noise and open-loop controls

We develop an exhaustive study of Markov decision process (MDP) under mean field interaction both on states and actions in the presence of common noise, and when optimization is performed over open-loop controls on infinite horizon. Such model, called CMKV-MDP for conditional McKean–Vlasov MDP, arises and is obtained here rigorously with a rate of convergence as the asymptotic problem of N-cooperative agents controlled by a social planner/influencer that observes the environment noises but not necessarily the individual states of the agents. We highlight the crucial role of relaxed controls and randomization hypothesis for this class of models with respect to classical MDP theory. We prove the correspondence between CMKV-MDP and a general lifted MDP on the space of probability measures, and establish the dynamic programming Bellman fixed point equation satisfied by the value function, as well as the existence of ϵ-optimal randomized feedback controls. The arguments of proof involve an original measurable optimal coupling for the Wasserstein distance. This provides a procedure for learning strategies in a large population of interacting collaborative agents.

On the stability of mean-field stochastic differential equations with irregular expectation functional

In this paper, we consider multidimensional mean-field stochastic differential equations where the coefficients depend on the law in the form of a Lebesgue integral with respect to the measure of the solution. Under the pathwise uniqueness property, we establish various strong stability results. As a consequence, we give an application for optimal control of diffusions. Namely, we propose a result on the approximation of the solution associated to a relaxed control.

Weaving Synchronous Reactions into the Fabric of SSA-form Compilers

We investigate the programming of reactive systems combining closed-loop control with performance-intensive components such as Machine Learning (ML). Reactive control systems are often safety-critical and associated with real-time execution requirements, a domain of predilection for synchronous programming languages. Extending the high levels of assurance found in reactive control systems to computationally intensive code remains an open issue. We tackle it by unifying concepts and algorithms from synchronous languages with abstractions commonly found in general-purpose and ML compilers. This unification across embedded and high-performance computing enables a high degree of reuse of compiler abstractions and code. We first recall commonalities between dataflow synchronous languages and the static single assignment (SSA) form of general-purpose/ML compilers. We highlight the key mechanisms of synchronous languages that SSA does not cover—denotational concepts such as synchronizing computations with an external time base, cyclic and reactive I/O, as well as the operational notions of relaxing control flow dominance and the modeling of absent values. We discover that initialization-related static analyses and code generation aspects can be fully decoupled from other aspects of synchronous semantics such as memory management and causality analysis, the latter being covered by existing dominance-based algorithms of SSA-form compilers. We show how the SSA form can be seamlessly extended to enable all SSA-based transformations and optimizations on reactive programs with synchronous concurrency. We derive a compilation flow suitable for both high-performance and reactive aspects of a control application, by embedding the Lustre dataflow synchronous language into the SSA-based MLIR/LLVM compiler infrastructure. This allows the modeling of signal processing and deep neural network inference in the (closed) loop of feedback-directed control systems. With only minor efforts leveraging the MLIR infrastructure, the generated code matches or outperforms state-of-the-art synchronous language compilers on computationally intensive ML applications.

Control charts for chronic disease surveillance: testing algorithm sensitivity to changes in data coding

BackgroundAlgorithms used to identify disease cases in administrative health data may be sensitive to changes in the data over time. Control charts can be used to assess how variations in administrative health data impact the stability of estimated trends in incidence and prevalence for administrative data algorithms. We compared the stability of incidence and prevalence trends for multiple juvenile diabetes algorithms using observed-expected control charts.MethodsEighteen validated algorithms for juvenile diabetes were applied to administrative health data from Manitoba, Canada between 1975 and 2018. Trends in disease incidence and prevalence for each algorithm were modelled using negative binomial regression and generalized estimating equations; model-predicted case counts were plotted against observed counts. Control limits were set as predicted case count ±0.8*standard deviation. Differences in the frequency of out-of-control observations for each algorithm were assessed using McNemar’s test with Holm-Bonferroni adjustment.ResultsThe proportion of out-of-control observations for incidence and prevalence ranged from 0.57 to 0.76 and 0.45 to 0.83, respectively. McNemar’s test revealed no difference in the frequency of out-of-control observations across algorithms. A sensitivity analysis with relaxed control limits (2*standard deviation) detected fewer out-of-control years (incidence 0.19 to 0.33; prevalence 0.07 to 0.52), but differences in stability across some algorithms for prevalence.ConclusionsOur study using control charts to compare stability of trends in incidence and prevalence for juvenile diabetes algorithms found no differences for disease incidence. Differences were observed between select algorithms for disease prevalence when using wider control limits.

Shape‐Mediated Magnetocrystalline Anisotropy and Relaxation Controls by Cobalt Ferrite Core–Shell Heterostructures for Magnetothermal Penetration Delivery

AbstractSimultaneous delivery of therapeutic agents and energy by magnetic nanoparticles (MNPs) at targeted sites can boost cancer therapy and alleviate side effects. To achieve this goal, however, the magnetic fluid hyperthermia (MFH) usually exhibits the unsufficient thermal efficiency due to their narrow magnetization curves. Besides, an inappropriately large administration concentration also causes health deterioration as shown in an animal model. In this study, the core–shell cube that enhances the coercivity and magnetization related to single‐compositional MNPs by elaborately tuning their interface relaxation via the magnetocrystalline and surface anisotropy is developed. Néel and Brownian relaxation can be adjusted by the particles’ structures to maximize the hyperthermia efficacy upon an alternating‐magnetic‐field (AMF). Furthermore, temozolomide and lactoferrin‐coated CoFe2O4@Fe3O4 core–shell cubes are rapidly internalized by targeting cancer cells and penetrate into tumor spheroids while subjecting to AMF. The targeted cubes with the capabilities of enhanced coercivity, AMF‐induced drug penetration into tumors, and magnetothermal ablation for cancer therapy display potentials for clinical uses.

A COVID-19 vaccination model for Aotearoa New Zealand

We develop a mathematical model to estimate the effect of New Zealand’s vaccine rollout on the potential spread and health impacts of COVID-19. The main purpose of this study is to provide a basis for policy advice on border restrictions and control measures in response to outbreaks that may occur during the vaccination roll-out. The model can be used to estimate the theoretical population immunity threshold, which represents a point in the vaccine rollout at which border restrictions and other controls could be removed and only small, occasional outbreaks would take place. We find that, with a basic reproduction number of 6, approximately representing the Delta variant of SARS-CoV-2, and under baseline vaccine effectiveness assumptions, reaching the population immunity threshold would require close to 100% of the total population to be vaccinated. Since this coverage is not likely to be achievable in practice, relaxing controls completely would risk serious health impacts. However, the higher vaccine coverage is, the more collective protection the population has against adverse health outcomes from COVID-19, and the easier it will become to control outbreaks. There remains considerable uncertainty in model outputs, in part because of the potential for the evolution of new variants. If new variants arise that are more transmissible or vaccine resistant, an increase in vaccine coverage will be needed to provide the same level of protection.

Statistical design of an adaptive synthetic X¯$\bar{X}$ control chart for autocorrelated processes

AbstractThis paper aims to design a variable parameters synthetic control chart for first‐order AR(1) autocorrelated data following a Gaussian process. To improve the statistical performance in detecting small changes and maintaining a low false alarm rate, the variable parameters control chart was combined with the Conforming Run Length (CRL) sub‐chart to determine when to implement tight or relaxed control and intervene to identify an assignable cause. The statistical design of the proposed chart was performed under a discrete‐time Markov chain approach and a non‐linear programming mathematical model to obtain, using a genetic algorithm (GA), the values of the design parameters that minimise the average time to signal the out‐of‐control state (). A sensitivity analysis was performed to examine the behaviour of the in the face on changes in the parameters. Also, a performance evaluation was conducted to compare the proposed chart with other adaptive synthetic charts, the synthetic control chart and the chart developed by Costa and Machado. Our results indicate that this proposal is faster to detect small changes in the process mean considering the autocorrelation of the data.

McKean–Vlasov Optimal Control: Limit Theory and Equivalence Between Different Formulations

We study a McKean–Vlasov optimal control problem with common noise in order to establish the corresponding limit theory as well as the equivalence between different formulations, including strong, weak, and relaxed formulations. In contrast to the strong formulation, in which the problem is formulated on a fixed probability space equipped with two Brownian filtrations, the weak formulation is obtained by considering a more general probability space with two filtrations satisfying an (H)-hypothesis type condition from the theory of enlargement of filtrations. When the common noise is uncontrolled, our relaxed formulation is obtained by considering a suitable controlled martingale problem. As for classic optimal control problems, we prove that the set of all relaxed controls is the closure of the set of all strong controls when considered as probability measures on the canonical space. Consequently, we obtain the equivalence of the different formulations of the control problem under additional mild regularity conditions on the reward functions. This is also a crucial technical step to prove the limit theory of the McKean–Vlasov control problem, that is, proving that it consists in the limit of a large population control problem with common noise.

NON-PHARMACHOLOGICAL THERAPY IN DECREASING BLOOD PRESSURE AMONG PREGNANT WOMEN: LITERATURE REVIEW

Pregnancy in which the body of a pregnant woman undergoes physical changes, and psychological changes due to increased pregnancy hormones. Hormonal changes during pregnancy cause changes in the cardiovascular system with increased blood pressure in pregnant women and triggers preeclampsia in pregnancy. The purpose of the literature study was to identify several non-pharmacological therapies in reducing blood pressure in pregnant women with preeclampsia. The research method used is a literature study with a narrative review approach. Search data using databases such as PubMed, EBSCO, and Google Scholar. The keywords used were “hypertension”, “non-pharmachological therapies”, “preeclampsia”, “pregnancy”. There were 7 articles that discussed non-pharmacological therapy by means of aerobic exercise, foot massage, progressive muscle relaxation and breathing control techniques, autogenic training, hydrotherapy, mushroom diet, cognitive behavioral therapy. Non-pharmacological therapy by reducing blood pressure in preeclampsia in pregnant women affects systolic and diastolic blood pressure during the therapy program with a period of time and a relaxation phase. In addition, other therapies reduce arterial stiffness in pregnant women with chronic hypertension.

Strain-rate of stretch affects crossbridge detachment kinetics during relaxation in twitching, intact cardiac trabeculae

We have recently shown that Mechanical Control of Relaxation (MCR), or the acceleration of relaxation by fast stretch, exists in intact cardiac trabeculae. Relaxation mechanisms include both calcium and crossbridge kinetics, but early studies of MCR suggest that crossbridge detachment may be accelerated by fast stretch (strain-rate). This study was undertaken to investigate strain-rate dependent crossbridge kinetics after a ramp-stretch during the relaxation phase of a twitch in intact cardiac trabeculae.

PENGARUH HIPNOTERAPI TERHADAP PENURUNAN KECEMASAN IBU HAMIL DAN BERSALIN

Psychological problems underlying the fear and anxiety will be embedded in the mother's subconscious mind, becoming negative thoughts. The psychological burden can lead to problems with labor complications, which interfere with the normal process of pregnancy and childbirth. The psychological condition of the mother who is less supportive can cause stress which can cause tense muscles, stiffness, labor pain and hard, inelastic birth canal. Negative thoughts accompanied by pain, will improve the work of the sympathetic nervous system. The hypothalamus sends a signal to the pituitary gland, to reduce the hormone cortisol, which is a stress hormone, so that the autonomic nervous system activates the adrenal glands causing physical tension in pregnant women which causes more pain. The purpose of this study was to determine the effect of hypnotherayi on reducing anxiety of pregnant and maternal mothers. This research article reviewed from electronic databases including Science Direct, Google Scholar and other related websites. The number of keywords used included 7 "Hypnotherapy" and "anxiety" From 1484 Publications ranging from 2008 to 2018, the use of the hypnotherapy method to reduce anxiety in pregnant women was presented in English, included in this review. Pregnant women who take hypnotherapy can reduce anxiety, gain peace of mind and instill positive thoughts on the subconscious mind because during the hypnotherapy process the mother experiences deep physical relaxation, focused attention, increased sensory ability, and relaxed control.

COVID-19 attributed mortality and ambient temperature: a global ecological study using a two-stage regression model

ABSTRACT A negative correlation between ambient temperature and COVID-19 mortality has been observed. However, the World Meteorological Organization (WMO) has reinforced the importance of government interventions and warned countries against relaxing control measures due to warmer temperatures. Further understanding of this relationship is needed to help plan vaccination campaigns opportunely. Using a two-stage regression model, we conducted cross-sectional and longitudinal analyses to evaluate the association between monthly ambient temperature lagged by one month with the COVID-19 number of deaths and the probability of high-level of COVID-19 mortality in 150 countries during time t = 60, 90, and 120 days since the onset. First, we computed a log-linear regression to predict the pre-COVID-19 respiratory disease mortality to homogenize the baseline disease burden within countries. Second, we employed negative binomial and logistic regressions to analyze the linkage between the ambient temperature and our outcomes, adjusting by pre-COVID-19 respiratory disease mortality rate, among other factors. The increase of one Celsius degree in ambient temperature decreases the incidence of COVID-19 deaths (IRR = 0.93; SE: 0.026, p-value<0.001) and the probability of high-level COVID-19 mortality (OR = 0.96; SE: 0.019; p-value<0.001) over time. High-income countries from the northern hemisphere had lower temperatures and were most affected by pre-COVID respiratory disease mortality and COVID-19 mortality. This study provides a global perspective corroborating the negative association between COVID-19 mortality and ambient temperature. Our longitudinal findings support the statement made by the WMO. Effective, opportune, and sustained reaction from countries can help capitalize on higher temperatures’ protective role including the timely rollout of vaccination campaigns.

Optimal control of a class of semilinear systems on Banach spaces driven by vector measures and relaxed controls

Optimal control of a class of semilinear systems on Banach spaces driven by vector measures and relaxed controls

A Safer World after Vaccination against COVID-19, Government Responses and Health Outcomes: A Comparative Study

During the first year of the COVID-19 Pandemic in 2020, world governments were split between the herd immunity strategy and that of strict social distancing. Health outcomes of 14 countries analyzed revealed unexpectedly high levels of deaths due to the disease, particularly among those countries which relaxed control as early as April 2020. Public health experts predicted that the COVID-19 Pandemic, though mutated into Delta, would come to an end in mid-2021 when vaccination became available. Unfortunately, the situation was more complicated and disappointing as the coronavirus mutated further into another generation. Omicron spread faster but was less fatal than the Delta, some early records showed. Some countries therefore have declared that the Pandemic was over while China, sticking to its zero infection policy, was still fighting to contain the Omicron variant. As Hong Kong has lost 3875 lives in the spring of 2022, a similar death rate projected for China would be astronomical. In China, the public health crisis has been prolonged, policies of social distancing remain upheld, and international doors cannot be opened. This study reviewed government responses and health performances of 14 countries in 2020, 2021, and early 2022. The 3 periods were characterized by the impact of COVID-19, Delta, and Omicron. Major indicators analyzed include data from Government Responses and Stringency Index developed by Oxford Tracker and health data provided by the WHO and John Hopkins University. Effects on economies and health care financing, mostly reported by the Economist Intelligence Unit, were also discussed.

Effect of Relaxation Therapy on Pre-Induction Blood Pressure and Anxiety in Hypertensive Patients

Abstract Background: Anxiety associated with surgical stress can lead to high blood pressure (BP), which may end up with undue last minute cancellation of surgery. Relaxation therapy is now being widely used as a complementary therapy for stress and high BP. We conducted a randomized controlled study to compare the effect of relaxation therapy on pre-induction anxiety and BP in hypertensive patients. Materials and Methods: A randomized controlled study was conducted on hypertensive patients undergoing elective surgery. They were allocated into two groups (relaxation therapy and control) using simple randomization with allocation concealment. The relaxation therapy group received intervention by an audio clip an evening prior and 30 min before the scheduled surgery. Their anxiety score on numerical rating scale (0–10) and BP was recorded before and after each intervention. The control group received standard care only. Pre-induction BP and anxiety score were recorded in both groups. The outcome measures were difference in pre-induction anxiety and BP between relaxation and control groups and difference in pre- and post-relaxation anxiety and BP. Results: Out of 70 patients, 30 received relaxation therapy and 34 received standard pre-operative care. There was a significant reduction in BP and anxiety after relaxation therapy in the intervention group (P &lt; 0.0001). The relaxation therapy group showed significantly lower pre-induction systolic BP (138.93 vs. 156.59, P &lt; 0.0001) and anxiety score (2.5 vs. 5.5, P &lt; 0.0001) than the control group. Requirement of anxiolytic drug was less in the relaxation therapy group. Conclusion: Relaxation therapy significantly reduces pre-induction BP and anxiety.

Optimal vector measures and relaxed controls for a class of nonlinear systems

Optimal vector measures and relaxed controls for a class of nonlinear systems

Supplemental Material for Pilot Study on Students’ Stress Reactivity After Mindfulness Intervention Compared to Relaxation Control Group

Supplemental Material for Pilot Study on Students’ Stress Reactivity After Mindfulness Intervention Compared to Relaxation Control Group

Cognitive Behaviour Therapy And Relaxation Technique on Examination Anxiety among Senior Secondary School Students in the Ibadan Metropolis, Nigeria

Examination anxiety is as old as examination itself, as long as examination exist, anxiety is bound to occur. Many students often feel anxious and exhibits lots of negative emotions towards examinations. These feelings of anxiety exhibited by the students generally has deleterious effects on the students and also on their academics and personality. This study therefore examined the use of Cognitive Behaviour Therapy and Relaxation technique on examination anxiety among Senior Secondary School students in the Ibadan metropolis. The moderating effects of emotional intelligence and academic self-efficacy were also examined. A pretest-posttest control group quasi- experimental design with a 3x2x2 factorial matrix was adopted. Multi-stage sampling procedure was employed. Three local government areas were randomly selected from Ibadan metropolis. One public secondary school were randomly selected from each of the local government area. Ninety (M=37; F= 53) Senior Secondary School students SS 1 and 2 were screened for the test anxiety and were randomly assigned to the Cognitive Behaviour Therapy (30) Relaxation Technique(30) and control group(30). Treatment lasted for eight weeks for the CBT and Relaxation Technique groups. Data were analysed using Analysis of Covariance and Multiple Classification Analysis at the 0.05 level of significance. The results indicated that there was significant main effect of treatments on examination anxiety of secondary school students. There was also significant main effect of emotional intelligence and academic self-efficacy on examination anxiety of secondary school students. Both CBT and relaxation technique were effective in managing examination anxiety among secondary school students. Counsellors and educational Psychologists should utilise these therapies to manage examination anxiety among students.

Relaxed control of sugar utilization in Parageobacillus thermoglucosidasius DSM 2542

Though carbon catabolite repression (CCR) has been intensively studied in some more characterised organisms, there is a lack of information of CCR in thermophiles. In this work, CCR in the thermophile, Parageobacillus thermoglucosidasius DSM 2542 has been studied during growth on pentose sugars in the presence of glucose. Physiological studies under fermentative conditions revealed a loosely controlled CCR when DSM 2542 was grown in minimal medium supplemented with a mixture of glucose and xylose. This atypical CCR pattern was also confirmed by studying xylose isomerase expression level by qRT-PCR. Fortuitously, the pheB gene, which encodes catechol 2, 3-dioxygenase was found to have a cre site highly similar to the consensus catabolite-responsive element (cre) at its 3′ end and was used to confirm that expression of pheB from a plasmid was under stringent CCR control. Bioinformatic analysis suggested that the CCR regulation of xylose metabolism in P. thermoglucosidasius DSM 2542 might occur primarily via control of expression of pentose transporter operons. Relaxed control of sugar utilization might reflect a lower affinity of the CcpA-HPr (Ser46-P) or CcpA-Crh (Ser46-P) complexes to the cre(s) in these operons.