Suboptimal Parameters Research Articles

Distributed event-triggered consensus of multi-agent systems under periodic DoS jamming attacks

This paper is concerned with distributed event-triggered consensus of a generally linear multi-agent system subjected to periodic denial-of-service (DoS) jamming attacks. First, a novel switched time-varying delay system model is established to describe consensus error dynamics. By virtue of the switched system and time delay system approaches, one constraint is obtained as a tradeoff between exponential convergence rate of consensus error and uniform lower bound of sleep intervals of periodic DoS jamming attacks. Second, sufficient conditions are derived to guarantee exponential consensus of the multi-agent system. Third, a co-design method is presented to determine the parameters of both the distributed event-triggered mechanism and consensus protocol. Furthermore, an algorithm is given to find the allowable uniform lower bound of sleep intervals and suboptimal distributed event-triggering parameters. Finally, an illustrative example is provided to verify the effectiveness of the proposed resilient event-triggering consensus design method against periodic DoS jamming attacks.

Sub-Optimal Second-Order Sliding Mode Controller Parameters’ Selection for a Positioning System with a Synchronous Reluctance Motor

This paper discusses nonlinear controller structure design for a synchronous reluctance motor (SynRM). The SynRM is represented with a nonlinear dynamic model. All presented nonlinearities of the SynRM are respected in the controller design procedure. A nonlinear controller policy is used for a SynRM positing system. The nonlinear controller design is based on the chattering alleviation technique for the super-twisted algorithm (STA). The alleviation technique assumes the presence of a fast parasitic dynamic, or fast, actuator. Based on the motor structure, the STA controller is designed only for the mechanical subsystem, where the electrical part presents the parasitic dynamic, and is taken in to account in the chattering suppression procedure. Chattering rejection is based on the STA describing function and harmonic balance equation. The approach allows determination of fast oscillation parameters, such as amplitude and frequency of oscillation. The conditions for the controller parameters’ selection are derived with regard to the given oscillation parameters. The derived conditions cover the stability analysis for the STA controller, as well as the stability condition for current controllers and chattering amplitude minimization. The result is confirmed with an example.

A two-parameter modified splitting preconditioner for the Bidomain equations

We study preconditioned iterative methods for the linear system arising in the numerical discretization of the Bidomain equations in electrocardiology. In each step of the time integration, a block two-by-two linear system is obtained and needed to be solved numerically. A preconditioning strategy based on an alternating splitting of the coefficient matrix is proposed to solve such linear systems. The method is a two-parameter modification of the splitting method recently introduced by Chen et al. (J Comput Appl Math 321:487–498, 2017). Theoretically, we demonstrate that the spectrum of the resulting preconditioned matrix shows a tight cluster at unity. The analytic values of the sub-optimal iteration parameters are established and numerical experiments are presented to illustrate the effectiveness of this approach.

Data-driven Minimum Variance Regulatory Control for Linear Parametrized Controllers

The paper proposes a linearly parametrized data-driven controller design method based on minimum variance evaluation. The approach updates control parameters that improves disturbance attenuation properties from regulatory control input and output measurements. The proposed method uses linearly parametrized controllers, and obtains sub-optimal control parameters based on variance evaluation. The paper considers a new data-driven cost criterion on the assumption that disturbance model is unknown. Then, the analysis using the approach of “Domain of Attraction (DOA)” is provided to confirm that minimization of the proposed cost criterion reduces the value of the original cost criterion. Finally, the paper shows the effectiveness of the proposed method through a numerical example.

Factors Associated With High-Voltage Impedance and Subcutaneous Implantable Defibrillator Ventricular Fibrillation Conversion Success.

The ability to predict defibrillation efficacy at the time of subcutaneous implantable cardioverter-defibrillator implantation without the need to induce ventricular fibrillation might eliminate the need for defibrillation testing. The purpose of this study was to determine the association of high-voltage impedance and system implant position on ventricular fibrillation conversion success with a submaximal 65-J shock. In the subcutaneous implantable cardioverter-defibrillator IDE study (Investigational Device Exemption), a successful conversion test required 2 consecutive ventricular fibrillation conversions at 65 J in either shock vector. Chest radiographs were obtained after implantation. Patients with imaging and impedance data were included. Suboptimal device position was defined as an inferior electrode or pulse generator or electrode coil depth >3 mm anterior to the sternum. Absence of suboptimal positional parameters was defined as appropriate position. Conversion success rate was calculated among all 65-J tests. Of 314 patients who underwent subcutaneous implantable cardioverter-defibrillator implantation, 282 patients were included in this analysis. There were 637 inductions to test defibrillation at 65 J. Sixty-two conversion failures (9.7%) occurred in 42 (14.9%) patients. Lower body mass index and lower shock impedance were associated with higher conversion success rate, whereas white race was associated with lower conversion success rate. Suboptimal position was more common in obese patients. Inferior electrode and greater distance between the lead and sternum were associated with a higher impedance. When appropriate system position was achieved, conversion failure was not associated with high body mass index. Subcutaneous implantable cardioverter-defibrillator shock efficacy is associated with system position and high-voltage system impedance. A high impedance is associated with inferiorly placed pulse generator and electrode system, inadequate coil depth, and a lower rate of defibrillator success. URL: https://www.clinicaltrials.gov . Unique identifier: NCT01064076.

Comparison of respiratory parameters in participants with and without chronic low back pain

BackgroundIndividuals with chronic low back pain (CLBP) may lack coordination between the stabilising and respiratory functions of trunk muscles. The trunk stabilisers compromise breathing to maintain spinal stability, leading to breathing dysfunctions. Maximal voluntary ventilation (MVV) is indicative of the respiratory muscle endurance and strength whereas end-tidal carbon dioxide (PETCO2) gives an estimate of breathing patterns that closely reflect the arterial measurement of CO2.CLBP has been shown to have a significant effect on respiratory functions. However, the impact has not yet been quantified. Further, there is a dearth of literature comparingrespiratory functions between CLBP and healthy individuals. This study investigates respiratory functions in participants with and without CLBP. MethodsThe study compared the respiratory functions of maximal voluntary ventilation (MVV) and End-Tidal Carbon Dioxide (PETCO2) between 14 participants with CLBP and 14 healthy individuals. Participants in both groups were matched for age, height, weight and body surface area. The assessment of MVV and PETCO2 were performed sitting, standing on a stable surface, and on an unstable surface (BOSU ball). ResultsThe mean of measured MVV (L/min) was found to be lower (p < 0.05) in the CLBP group when compared to the healthy group. Mean PETCO2 and respiratory rate was found to be higher in CLBP group when compared to the healthy group in all three positions, although this was not found to be statistically significant. ConclusionThe findings of this study demonstrated sub-optimal respiratory parameters in participants with chronic low back pain. However, when adjusted for gender, the difference was not found to be significant between the two groups.

Computer Model Calibration with Confidence and Consistency

SummaryThe paper proposes and examines a calibration method for inexact models. The method produces a confidence set on the parameters that includes the best parameter with a desired probability under any sample size. Additionally, this confidence set is shown to be consistent in that it excludes suboptimal parameters in large sample environments. The method works and the results hold with few assumptions; the ideas are maintained even with discrete input spaces or parameter spaces. Computation of the confidence sets and approximate confidence sets is discussed. The performance is illustrated in a simulation example as well as two real data examples.

The Effect of Suboptimal Semen Parameters on Male Partner's Ability to Conceive. Is He Really Subfertile Because the Test Says So?

Context:In many developing countries, subfertility treatment is not covered by government-funded institutions. It is observed that healthcare providers incriminate male factor for subfertility even when only a slight deviation from presumed normal criteria is observed.Aim:This study aims to provide scientific evidence that pregnancies are possible at semen parameters that are below the generally accepted lower limits of normal.Setting and Design:This was a retrospective cohort study conducted from January 2014 to December 2018.Materials and Methods:During the study period, couples who conceived without any treatment of male partner were included. The World Health Organization (WHO) reference values for semen analysis were utilized to assess the reports. The primary outcome measure was conception despite abnormal semen parameters.Statistical Analysis Used:Data were analyzed using the SPSS software program, version 15.0 (IBM, Armonk, USA).Results:Of the 332 couples included, 233 (70.1%) couples conceived despite suboptimal semen parameters, The most common criterion not satisfied was rapid linear motility –200 (85.8%), 87 (37.3%) men were oligozoospermic, 94 (40.3%) were asthenozoospermic, and 21 (9%) were teratozoospermic. The abnormalities were more common in men having primary subfertility (71.7% vs. 28.3%, P = 0.002). The abnormalities were most common in the age group 40–44 years (n = 91, 39.1%) and those who were overweight (n = 110, 47%).Conclusions:A consensus for defining poor semen criteria is the need of the hour so that these males can be counseled satisfactorily. WHO criteria are a standard commonly employed, but they do not necessarily predict the fertility potential.

Control issues of a fast positioner intended for deflection of a high power laser beam

This paper discusses some crucial aspects of control of a fast positioner intended for positioning of a mirror reflecting high power laser beam. Positioner is driven by a two linear movement piezo actuators acting on a common flexible flat spring bending it in two perpendicular directions. The reflector is fixed to this spring. Clearly, the actuator is a dynamic oscillating system. This makes control of positioner demanding. In order to overcome the effects of static nonlinearity, hysteresis and their time evolution, there were proposed two independent closed loop positioning systems each governing each own axis. The simulation investigations allowed for determining the suboptimal structure and parameters of controllers. Two different control loops were investigated and discussed. The simulation experiments shown, that the most efficient controller is able to “mask” the actuator hysteresis while introducing appropriate dynamic damping and stiffness to the controlled system. The concept of the positioner controller was described and some chosen results of laboratory experiments were presented. Finally, the assessment of the control quality is given together with some general conclusions closing the paper.

Tailored laser vector fields for high-precision micro-manufacturing

Laser processes used in high-precision micro-manufacturing are limited to sub-optimal parameters determined by the inherent characteristics of chosen laser beams and optics. As a result, the processing accuracy and speed can be reduced. Optical techniques for spatial structuring of laser beam fields allow improved resolution imaging, yet this has not widely been used in the context of laser micro-manufacturing. This paper presents materials processing with structured beams to engineer tailored focal fields and produce specific surface structures on silicon. Our results using radial and azimuthal fields combined with vortex wavefronts illustrate the potential of these techniques for micro-processing applications.

Novel Strategies To Activate the Dopamine D1 Receptor: Recent Advances in Orthosteric Agonism and Positive Allosteric Modulation.

The five dopamine receptor subtypes (D1-5) are activated by the endogenous catecholamine dopamine. Sustained research has sought to identify selective ligands for receptor subtypes. In particular, activation of the D1 receptor has attracted attention due to its promising role in neurological diseases. Initial attempts to identify agonists yielded catechol derivatives, mimicking dopamine, with suboptimal DMPK parameters and low selectivity over the D5 subtype. However, more recent efforts to identify ligands capable of activating the D1 receptor have made substantial progress with the identification of non-catechol agonists with suitable properties to progress to clinical studies. In addition, several research groups have identified positive allosteric modulators that offer new potential. Furthermore, structural studies have surprisingly uncovered two potential allosteric binding sites, the most characterized of which appears to be on intracellular loop 2 (ICL2). This review highlights the recent progress in the field, covering both orthosteric and allosteric modes of activation, discusses the elucidation of the allosteric binding sites, and summarizes the clinical development status of various compounds.

Racial and Sociodemographic Differences of Semen Parameters Among US Men Undergoing a Semen Analysis

ObjectiveTo characterize sociodemographic differences in semen parameters among US men undergoing a semen analysis. Materials and MethodsMen who provided a semen sample were identified from insurance claims between 2007 and 2016. Differences in semen parameters were characterized according to age, race, education, and region. Mean semen parameters and proportions of men with suboptimal parameters were compared and risks of oligospermia and azoospermia were assessed by logistic regression. ResultsOf the 7263 men included, most men were white (55.1%), Hispanic (20.2%), or Asian (10.2%). Asians had the highest mean semen concentrations (69.2 × 106/mL), whereas blacks had the lowest (51.3 × 106/mL). Men from the Midwest were more likely to have oligospermia (odds ratio [OR] 1.62; 95% confidence interval [CI] 1.34-1.94), whereas men from the West were less likely (OR 0.82; 95% CI 0.82-0.94) when compared with men from South. An association between education and sperm concentration was observed. For example, men with a high school diploma or less were more likely to have oligospermia (OR 1.09; 95% CI 0.95-1.26), whereas men with at least a bachelor degree were less likely (OR 0.87; 95% CI 0.76-1.0) when compared with men with less than a bachelor degree. ConclusionAs we observed differences in semen quality based on sociodemographic factors, these findings may have clinical implications as relying on a single reference value when guiding infertile couples may be problematic given these variations. Further work is warranted to understand the etiology of such differences and determine if different normative reference values may apply for different populations.

His-bundle pacing as a standard approach in patients with permanent atrial fibrillation and bradycardia.

His-bundle (HB) pacing is the most physiological method of ventricular pacing. However, it is also considered a demanding procedure with a low success rate and has suboptimal pacing parameters. There is a scarcity of data concerning HB pacing as a standard approach in patients with symptomatic bradycardia. Our goal was to compare acute and chronic results of two approaches to pacing in patients with permanent atrial fibrillation, narrow QRS complexes, and symptomatic bradycardia: right ventricular myocardial pacing versus HB pacing. Consecutive patients who received HB pacemakers were compared with historical controls-i.e., consecutive patients with classic VVI pacemaker implantations, performed by the same operator before 2014 (commencement of routine HB implantations). Acute and long-term capture threshold, sensing, battery current drain, as well as procedure and fluoroscopy duration, complications, and success rate were compared. One hundred and twenty-five patients were analyzed (including 65 patients with HB pacing): age 73.0 ± 10.5 years, left ventricular ejection fraction of 48.2 ± 13.5%. HB pacing was inferior to right ventricular myocardial pacing in terms of higher threshold, lower sensing amplitude, higher current drain, lower success rate, longer procedure, and fluoroscopy times. However, despite this, HB procedure and fluoroscopy times of 64.4 ± 30.0 and 11.0 ± 10.7minutes, respectively, long-term successful HB pacing in 87.9% of patients, a chronic threshold of 1.5 ± 1.1V, chronic sensing of 3.6 ± 2.5mV, and chronic current drain per pulse of 3.4 ± 4.4μAh seem acceptable. HB pacing can be used as an alternative standard method of pacing in atrial fibrillation patients.

ВИКОРИСТАННЯ БІОРЕЗОНАНСНИХ ТЕХНОЛОГІЙ В УМОВАХ РАЙОННОЇ ПОЛІКЛІНІКИ

Мета – зробити короткий огляд розвитку і трансформації рефлексотерапії в біорезонансну діагностику і терапію в умовах районної поліклініки. На конкретному прикладі показати окремі діагностичні і терапевтичні можливості вегетативного резонансного тесту (ВРТ), використовуючи оптимальний алгоритм діагностики і методику підбору частотних характеристик інформаційних копій гомеопатичних препаратів.Матеріал і методи. Діагностику і терапію проводили на апаратно-програмному комплексі «ИМЕДИС-ЭКСПЕРТ». Використовували програмне забезпечення Імедіс-Експерт, версія 6.30, апарат «МИНИ-ЭКСПЕРТ ДТ», апарат «МИНИ-ЭКСПЕРТ Д+», електронний медикаментозний селектор (версія 25 і вище) , апарат для адаптивної біорезонансної терапії «ИМЕДИС-БРТ», матеріали конференцій і з’їздів.Для пошуку ефективних резонансних препаратів для лікування була використана ідея С. Ганемана про міазми, яка характеризує основні закономірності розвитку і перебігу хронічних захворювань. З сучасних позицій міазм можна уявити як чітко детерміновану програму, за якою прогресивно набуває розвитку патологічний процес, незалежно від етіологічного фактора. Вся багатоманітність цієї програми проявляється в конкретних конституційних типах, закладених в патогенез гомеопатичних препаратів. Всі патологічні коливання, виявлені у конкретного хворого, відповідають неоптимальному рівню тієї чи іншої системи органів, тканин, міжкапілярної і міжклітинної рідин, крові, лімфи, клітини, видів обміну, біохімічних показників та інших процесів. Ця неоптимальність характеризує і неоптимальні міазми в даний конкретний відрізок часу. Використовуючи такий підхід через неоптимальні міазми можна підібрати максимально ефективний препарат для конкретного міазму, поступово нівелюючи всі виявлені неоптимальні параметри, і тим самим повернути організм до фізіологічної норми.Результати. Позитивний результат лікування конкретного пацієнта на основі діагностичних даних, отриманих методом ВРТ, а також результати лікування хворих з іншою патологією підтверджують необхідність ширшого використання методу в клінічній практиці.Висновки. Метод біорезонансної діагностики і терапії заслуговує на більш широке використання лікарями різних спеціальностей як експрес-метод діагностики. Терапія інформаційними копіями гомеопатичних препаратів дає прогнозовані позитивні результати при вмілому користуванні.

Level of NO/nitrite and 3-nitrotyrosine in seminal plasma of infertile men: Correlation with sperm number, motility and morphology

Nitric oxide (NO) is a signaling molecule responsible for initiation of molecular events that influence sperm functionality in a concentration-dependent manner. It is still not fully understood how seminal plasma NO contributes to sperm pathologies. The aim of this study was to elucidate whether and how NO is implicated in etiology of different sperm abnormalities.To this end we determine NO, nitrite and 3-nitrotyrosine (3-NT) content in seminal plasma of infertile men with specific pathologies (terato-, oligoterato- and oligoasthenoteratospermia) and relate it to infertile normospermic samples. To gain further understanding of NO metabolism in seminal plasma we determine protein expression of endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS).Here we show that NO, nitrite and 3-NT levels in seminal plasma of men with suboptimal semen parameters are significantly lower compared to normospermic men. An increase in protein expression of eNOS and no change in protein expression of iNOS is observed in men with sperm pathologies. Association of seminal plasma 3-NT level with functional sperm parameters is observed - positive correlation with sperm count, motility and morphology in normospermia, teratospermia and oligoteratospermia, as well as negative correlation with sperm morphology and motility in oligoasthenoteratospermia.Present study revealed that suboptimal seminal plasma NO content is found in all examined sperm pathologies. This result unequivocally shows the importance of NO for sperm function and involvement of suboptimal NO level in etiology of sperm abnormalities. Lower seminal plasma 3-NT level and its significant association with sperm parameters, found in pathologies, strongly indicates that protein nitration is important for spermatozoa function and that failure to establish this post-translational protein modification might be involved in etiology of sperm abnormalities. According to our results, NO measurement can discriminate infertile men with sperm pathologies from infertile normospermic men but is not indicative of a specific type of sperm pathology.

Clinical associations of maternal thyroid function with foetal brain development: Epidemiological interpretation and overview of available evidence

Thyroid hormone is an important regulator of early brain development, particularly during early stages of gestation during which foetal thyroid hormone availability depends on the maternal transfer of thyroid hormones. There is a wide range of experimental studies showing that low maternal thyroid hormone availability is associated with suboptimal brain development parameters. While few clinical studies have shown that overt maternal hypothyroidism is associated with lower child IQ, the question whether more subclinical changes in maternal thyroid function could also lead to suboptimal foetal brain development. In this review, we put the latter studies in perspective and discuss their interpretation from an epidemiological and clinical perspective. Furthermore, we extend this discussion to also include future perspective and identify important knowledge gaps in the field.

Review of optimum temperature, humidity, and vapour pressure deficit for microclimate evaluation and control in greenhouse cultivation of tomato: a review

Abstract Greenhouse technology is a flexible solution for sustainable year-round cultivation of Tomato (Lycopersicon esculentum Mill), particularly in regions with adverse climate conditions or limited land and resources. Accurate knowledge about plant requirements at different growth stages, and under various light conditions, can contribute to the design of adaptive control strategies for a more cost-effective and competitive production. In this context, different scientific publications have recommended different values of microclimate parameters at different tomato growth stages. This paper provides a detailed summary of optimal, marginal and failure air and root-zone temperatures, relative humidity and vapour pressure deficit for successful greenhouse cultivation of tomato. Graphical representations of the membership function model to define the optimality degrees of these three parameters are included with a view to determining how close the greenhouse microclimate is to the optimal condition. Several production constraints have also been discussed to highlight the short and long-term effects of adverse microclimate conditions on the quality and yield of tomato, which are associated with interactions between suboptimal parameters, greenhouse environment and growth responses.

Depth Map Estimation based on Maximum a Posteriori Probability

In this paper, we consider depth map estimation expressed as an optimization problem. We focus on the fitness function, for which we present a theoretical derivation based on a maximum a posteriori probability (MAP) rule. This is then used to show relations of interest with commonly used similarity metrics: sum of absolute differences (SAD) and sum of squared differences (SSD). The original derivations are also used to propose a depth estimation method. The experimental results are obtained with an implementation made on the basis of Moving Picture Expert Group (MPEG) Depth Estimation Reference Software (DERS). We show that with the proposed approach, it is possible to estimate a depth that allows higher quality of view synthesis (up to 2.8 dB of PSNR – Peak Signal-to-Noise Ratio) versus the original unsupervised DERS, when sub-optimal control parameters are used. If the DERS control parameters are optimized manually, the attained gain is smaller (up to 0.08 dB PSNR) but still does not need manual selection of control parameters.

Male Infertility- Current Concepts and Advances in Evaluation and Management- A Review

Globally Infertility and problems of impaired fecundity have been a concern. Which affects 8-12% of couples worldwide of all infertility cases, approximately 40-50% is due to “male factor” infertility and as many as 2% of all men will exhibit suboptimal sperm parameters. The cause is multifactorial. The rate of infertility in developing countries is markedly higher. In many a cases there is no definite etiology and it is termed as “Idiopathic Male Infertility. However research in the field of genetics, proteomics has changed the face of male infertility. This review is done to bring home the newer trends in evaluation and management of male infertility.

Experimental Study of Inconel 718 Surface Treatment by Edge Robotic Deburring with Force Control

We present the results of investigations into the application of robotics for deburring and chamfering to a predefined geometric quality. The robotic application was used for a part of the manufacturing process of an aircraft engine detail. Aircraft engine diffuser machining requires manual deburring of many edges. Finishing by hand results in several non-conforming quality details for each diffuser. This paper presents the concept of edge deburring with a controlled force progression pneumatic tool. A specific methodology was used to select and optimise the edge deburring process for robotic chamfering processing to a finer machining tolerance. The investigated machining process included a measurement system for the determination of the manufactured chamfer as a function of contact forces with feed force progression. The investigation work discussed in the paper helped to identify a specific interval of processing parameters, including the contact force and TCP motion velocity at which deburring is effective and a chamfer with specific geometric tolerance is produced. The experimental part of the investigation was conducted at a preset feed force of the high-speed machining file, tool ref. FDB150. The experimental machining sample was made from poorly machinable titanium alloy (Inconel 718), a material applied in the aerospace industry. The machining process optimisation included an approximation of the chamfer width definition points. The resulting function provided a derivative, defining the chamfer value change rate and corresponding to the actual machining tool infeed. The experimental measurement results were compared to the assumed quality indicators, by which a group of suboptimal parameters was defined.