Pre-defined Time Research Articles

Predefined-time synchronization of incommensurate fractional-order competitive neural networks with time-varying delays

This paper focuses on the predefined-time synchronization (PTS) of incommensurate fractional-order competitive neural networks (IFCNNs) with bounded or unbounded time-varying delays in the sense of Caputo fractional derivative (CFD). To this end, based on the piecewise Lyapunov function, a novel predefined-time stability theorem (PTST) is presented, where the setting of an adjustable time parameter in the deduced results makes it to be more versatile and more flexible, which refines former studies and can infer a series of new results. Besides, a double-layers predefined-time controller with two different fractional-order integrals is proposed, where the predefined time (PT) is predefined during the control design and can ensure that before a known time. Using this new PTST and some inequality techniques, an effective criteria for ensuring the PTS for two IFCNNs is derived in terms of algebraic inequalities. The PT is set to any positive parameter in the controllers and wholly independent of the initial values. Finally, examples are given to verify the proposed results.

Simulation Modelling of Cloud Mini and Mega Data Centers Using Cloud Analyst

Cloud Computing has now become a base technology for various other technologies including Internet of Things, Big Data Technologies and many other technologies, the responsibility of Cloud become critical in case of real time applications where the cloud services are required in real time. Delay in the response from Cloud may lead to serious consequences even loss of lives where the processes data from cloud must reach within predefined time interval. The performance of Cloud has experienced delays with the current infrastructure due to multiple issues in Traditional Cloud Network Model. The Paper suggests a proposed architecture Cloud Mini Data Centers simulated using Cloud Analyst to minimize the delays of Cloud Service delivery. The paper also simulate traditional cloud Network model using Cloud Analyst and provides a comparative study of both models.

Planning insect surveys in alpine ecosystems

Most biological survey programs rely on multi-species inventories (e.g. birds, amphibians, butterflies, dragonflies). These programs usually rely on multiple visits during pre-defined time windows. The implicit goal of this popular approach is to maximize the observed species richness. Here, we present a novel method to optimize the timing of survey windows using a framework maximizing the detectable species pool. We present a proof of concept using 20 years of entomological records in Switzerland using butterflies, dragonflies, and grasshoppers. The general framework presented can potentially be applied to a wide range of biological survey schemes. It offers a new practical tool for adaptive entomological monitoring under climate change.

Implementation of Standardized Outcome Measures for Motor Function in a Neurorehabilitation Hospital

International guidelines recommend the use of standardized outcome measures post-stroke. The aim of this study was to delineate and evaluate the implementation of four motor function outcome measures. This study describes the application of a multifaceted strategy that integrates various approaches to augment implementation. The study was conducted among physical therapists in a sub-acute neurorehabilitation hospital. The implementation process was guided by the Knowledge-to-Action Cycle, and a taxonomy for implementation outcomes was systematically employed to analyze and evaluate the implementation process. Focus group interviews were conducted both prior and 6 months subsequent to an implementation period. Additionally, data from healthcare records were extracted to monitor the penetration of the new procedures. All 70 employed physical therapists underwent training on the application of the four selected outcome measures. Barriers identified in the focus group interviews encompassed perceived acceptability and appropriateness of the outcome measures, time consumption for testing, and perceived lack of relevance for certain patients. These barriers were mitigated through local adaptions. However, 6 months post-implementation, the adoption and penetration of the new procedures were only partially satisfactory. Some physical therapists still expressed reluctance toward employing outcome measures, and findings from the healthcare records corroborated the interview results. Specifically, adherence to testing procedures surpassed the pre-defined threshold of 75% for only one outcome measure at one pre-defined time point. A persistent effort is required to enhance acceptability, adoption, penetration, and to ensure the sustainability of the new procedures.

Predefined-Time Adaptive Fault-Tolerant Control for Switched Odd-Rational-Power Multi-Agent Systems

This paper studies the distributed adaptive neural network (NN) predefined-time (PT) fault-tolerant consensus tracking control for unknown non-strict feedback nonlinear multi-agent systems (MASs) with time-varying full state constraints (TVFSCs), arbitrary switching behavior functions (possibly asynchronous), actuator faults and high powers. Compared with existing results, the convergence time estimation bound in this paper is less conservative due to the upper bound of convergence time presents as a tuning parameter. This paper avoids the control gain of each virtual controller to appear in the next virtual controller by using separable function technique, so it can reduce the control action complexity. Besides, this paper does not use any filters or piecewise continuous function in the controller design process, which can effectively avoid the potential singularity problem. An adaptive NN fault-tolerant consensus tracking controller is designed via backstepping technique and tangent barrier Lyapunov functions (BLF-Tans), which can ensure that all the closed-loop signals are bounded within a PT and the TVFSC bounds are not violated. Finally, numerical simulation and practical example further verify the effectiveness of the presented control algorithm. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —Many practical (underactuated, weakly coupled and unstable mechanical systems) control systems can be modeled as uncertain high-order MAS with high powers. Due to the influence of environment and other factors, the values of some variables in the practical systems are limited and cannot be arbitrarily selected. In addition, the actual systems may fail due to human factors and in most of the relevant literatures, it is often assumed that the powers are equal to 1 and only achieve the controlled systems asymptotic stability as time approaches infinity. Therefore, in this paper, an adaptive PT fault-tolerant control scheme is developed for MASs with high powers, time-varying full state constraints and actuator faults. The effectiveness of the control scheme is illustrated based on simulation study.

Nonlinear disturbance observer-based robust predefined time tracking and vibration suppression control for the rigid-flexible coupled robotic mechanisms with large beam-deformations

Nonlinear disturbance observer-based robust predefined time tracking and vibration suppression control for the rigid-flexible coupled robotic mechanisms with large beam-deformations

Long-Term Outcome in Stroke: The Need of Individualized Follow-Up

Introduction: It is well established that in the long-term, many stroke patients potentially have relevant functional incapacity related to deficits in domains other than motor; the burden of unmet long-term needs likely varies between different types of stroke or different healthcare systems. On the other hand, we can say that the ideal length of follow-up in a specialized consultation after ischemic stroke has not been established. Methods: We evaluated long-term stroke patients who underwent endovascular treatment of anterior circulation in our stroke center and that were classified as “therapeutic success” (modified Rankin scale - mRS &lt;3) at 3 months, to participate in an observational, cross-sectional study. Participants underwent a comprehensive interview and examination using validated standard questionnaires for Portuguese population to assess different life aspects after stroke as Post-Stroke Checklist, EQ-5D-3L scale, mRS, Barthel Index (BI), Burden Scale for Family Caregivers and Hamilton scale. Results: We evaluated 36 patients. The mean age was 67.6 years old (±13,8) and the mean time for the interview was 52,8 (±9,9) months after the stroke. Most patients were independent, with a mean mRS of 1 (ranging from 0–3) and BI 95,4 (70-100). Sixty one percent had a clinically significant deficit in at least one domain. On the Post Stroke Checklist (PSC), 77,8% of participants demonstrated a not good perceived health status. EuroQoL index value was 0.750 (IQR 0.664–1.00). The two major disability parameters identified were in cognition (52,8%) and depression (27,8%). After review of the ongoing care by stroke specialists, in almost 2/3 of the patients, additional measures were proposed: additional etiological investigation (44%), physical or speech rehabilitation (~14%) or changes in pharmacological therapy (~3%). Conclusion: These results highlight the prevalence and importance of non-motor disabilities in long-term stroke patients, even after short-term classification as “therapeutic success”. We also point out that even after more than 3 years of the stroke, additional therapeutic or etiological investigation measures were taken, reinforcing the need for individualized follow-up, without a pre-defined maximum follow-up time in a specialized cerebrovascular pathology consultation.

An effective framework to improve the managerial activities in global software development

Abstract Global Software Development (GSD) is a contemporary approach to software development that offers numerous advantages, including enhanced cost-effectiveness and timely delivery. It enables access to a vast pool of skilled developers and facilitates the exchange of best practices and innovative ideas within the software industry. However, effective project management plays a vital role in ensuring successful product development. Organizations that achieve project success consistently adhere to well-defined project management methodologies, resulting in desired outcomes within predefined time frames and allocated resources. The success rate of software projects significantly increases with diligent software management efforts. Nevertheless, the distributed nature of GSD presents significant challenges related to collaboration, information dissemination, and process control, which ultimately impede effective development and compromise software quality. In this study, we identify various challenges associated with the GSD process and propose strategies to overcome obstacles to effective project management. Additionally, we introduce a comprehensive framework designed to enhance managerial activities in GSD.

Comparisons between diluted thrombin time, ecarin chromogenic assays, and UPLC-MS for plasma level dabigatran quantification: Results from DRIVING study.

The knowledge of dabigatran levels is helpful for decision-making in specific situations such as urgent surgery or when the question of reversal arises (uncontrolled bleeding, eligibility for thrombolysis). However, a limited number of observational studies are available regarding comparisons between quantification methods. The objective of the study was to compare dabigatran plasma levels using three assays including the reference method (high-performance liquid chromatography coupled with mass spectrometry), focusing on the agreement around the 30-50 ng/mL clinically relevant thresholds. Sixty healthy volunteers from DRIVING trial (NCT01627665) were given a single 300-mg dabigatran etexilate dose. Serial blood samplings were performed at pre-defined time points (0 to 24 h). We analyzed plasma samples using ultra-performance-liquid chromatography coupled with tandem mass spectrometry (UPLC-MS) (dabigatran reference method); ii/diluted thrombin time (dTT) (Hemoclot-DTI-Hyphen-Biomed); iii/ecarin-based chromogenic assay (ECA-II-Stago). Nine hundred sixty samples were analyzed using the three assays (2759 values). dTT and ECA-II values were highly correlated with those of UPLC-MS (Deming regression). Most values >50 ng/mL were higher using dTT and ECA-II compared to UPLC-MS: biases were constant, +14% and +16% with dTT and ECA-II, respectively (Bland-Altman plots), suggesting that active metabolites accounted for ~15% of thrombin inhibition. Regarding values <30 ng/mL, 30-50 ng/mL, or ≥50 ng/mL, the agreement probability between dTT and ECA-II was of 90.6% [88.4-92.5] (Cohen's kappa coefficient 0.84). dTT and ECA-II assays rapidly provide accurate dabigatran-level results for clinical practice, both assays being suitable in emergency, taking into account the thrombin inhibitory effect of dabigatran metabolites.

Predefined-time synchronization for competitive neural networks with different time scales and external disturbances

This paper presents a study on the predefined-time (PdT) and practical PdT synchronization of competitive neural networks (CNN) in the presence of different time scales and external disturbances. Two types of external disturbances, which satisfy Lipschitz or bounded conditions, are investigated respectively. The new PdT and practical PdT stability theorems are derived in singularly perturbed systems, where the final residual set is given in detail. By employing the newly derived stability theorems, novel autonomous controllers are designed without relying on a continuous linear term and time scale parameters, while enabling PdT or practical PdT synchronization for drive-response CNNs. Additionally, upper bounds for the settling time are estimated, allowing for adjusting the predefined synchronization times regardless of the initial conditions. Finally, numerical simulations are conducted to demonstrate the effectiveness of the main results.

PF-BERxiT: Early exiting for BERT with parameter-efficient fine-tuning and flexible early exiting strategy

The industrial usage of huge pre-training language models such as BERT and ALBERT are limited by the computational probability problem in the fine-tuning process and overthinking problem in the inference process. PF-BERxiT has been proposed to optimize the pre-trained languages with a novel parameter-efficient fine-tuning method and a flexible early exiting strategy. Significantly, the new parameter-efficient fine-tuning model integrates a bottleneck adapter architecture parallel to the transformer architecture, and only the adapter's parameters are adjusted. In addition, we integrate an extra sub-learning module to learn the samples' characteristics, improving the accuracy and efficiency simultaneously. The flexible exiting strategy allows the model to exit early if the similarity score of adjacent layers is less than the threshold for pre-defined times. It is more flexible than previous early exiting methods, for it can simultaneously adjust the similarity score thresholds and patience parameters according to the request traffic. Extensive experiments are conducted on the GLUE benchmark, demonstrating that: (1) PF-BERxiT outperforms conventional training and parameter-efficient strategies with only a few parameters fine-tuned. (2) PF-BERxiT strikes a better balance between model performances and speedup ratios than previous state-of-the-art (SOTA) early exiting methods such as PABEE and BERxiT. (3) Ablation studies in the fine-tuning process demonstrate that the best bottleneck dimension r of the adapters is 32, and the adapters placed parallel to the feed-forward module are more efficient. (4) Ablation studies in the inference process demonstrate that for variants of PF-BERxiT with different similarity scores, PF-BERxiT-kl and PF-BERxiT-bikl attain better speedup-accuracy trade-offs than PF-BERxiT-rekl. Our PF-BERxiT helps attain a better trade-off between performance and efficiency, providing a reference for the efficient application of neural computing.

Vector Control Lyapunov Function Based Stabilization of Nonlinear Systems in Predefined Time

Predefined-time stability is the stability of dynamical systems whose solutions approach the equilibrium point within a pre-decided time duration. In this technical note, we develop general results of predefined-time stability of nonlinear systems using vector Lyapunov functions. A vector comparison system, which is predefined time convergent, is constructed, and after that the stability of the original dynamical system is proved using differential inequalities and comparison principles. Moreover, we design predefined-time controllers for large-scale systems using vector control Lyapunov functions (VCLFs). Sliding mode control is introduced in the design approach to mitigate matched bounded disturbances/uncertainties. Also, we aggregate comparison systems to reduce their dimensionality in order to effectively apply the derived results on practical systems. The theoretical results are implemented on a 2 DOF Helicopter model.

Predefined-time synchronization of fractional-order memristive competitive neural networks with time-varying delays

This article focuses on the predefined-time synchronization (PTS) of fractional-order memristive competitive neural networks (FMCNNs) with time-varying delays. According to the two-layer structural characteristics of CNNs, two kinds of distinctive discontinuous bilayer predefined-time control schemes with the fractional integrals are proposed: one is the double controllers based on piecewise Lyapunov function and the other is a controller with Lyapunov function and exponential function. Using the predefined-time stability theorems and applying fractional-order differential inequalities and other inequality techniques, some effective criteria are obtained to assure the PTS of two FMCNNs in terms of algebraic inequalities, which are very succinct and avert complicated calculations. Besides, the predefined time (PT) is set to an arbitrary positive parameter in these controllers and is entirely irrelevant to the initial values. Finally, two concrete examples are given to verify the theoretical results.

Fixed/predefined-time synchronization of coupled memristor-based neural networks with stochastic disturbance

In this paper, with the design of a unified adaptive controller, the fixed-time (FXT) and predefined-time (PDT) synchronization problems of coupled memristor-based neural networks (CMNNs) with stochastic disturbance is studied. The FXT synchronization of CMNNs with stochastic disturbance via adaptive control is investigated, some sufficient conditions for FXT synchronization and a less conservative settling time independent of the initial state are given. By modifying the parameters of the same controller, the synchronization scheme of CMMNs within an arbitrary predefined time, which is not related to the system and controller parameters, is designed. Numerical simulations are finally given to verify the validity of the obtained theoretical results and the feasibility of the secure communication scheme.

Encryption algorithm based on fractional order chaotic system combined with adaptive predefined time synchronization

An image encryption and decryption method of fractional order chaotic systems (FOCS) with predefined time synchronization is proposed in this article. Compared with the existing integer order chaotic systems (IOCS), fractional order chaotic systems has the advantage of increasing the complexity of the ciphertext. At the same time, by using the predefined synchronization time, the key space is expanded, the complexity of the key is increased, and the security of the algorithm is improved. To further improve the security of encryption and decryption process, this article uses a combination of DNA encoding, row/column cyclic shift and XOR diffusion, position scrambling and Arnold scrambling. The simulation tests of image encryption and decryption are carried out, and the effectiveness and advantages of the proposed encryption/decryption method are verified by histogram analysis, correlation analysis, entropy analysis, key sensitivity analysis and plaintext sensitivity analysis.

Three-dimensional predefined-time impact angle control guidance law with field-of-view limit

In this paper, an impact angle control guidance (IACG) law with predefined convergence time and seeker’s field-of-view (FOV) limit is proposed in three-dimensional (3D) scenario. First, a predefined-time error dynamic is developed whose significance is revealed by comparison with conventional methods. Second, based on coupled engagement dynamics, a 3D predefined-time IACG law is derived by applying the proposed error dynamic. To tackle the FOV limit, two auxiliary functions are introduced into the IACG law. The robustness against disturbances and uncertainties is further improved by utilizing the terminal sliding mode technique. With the proposed guidance law, the impact-angle error can converge to zero exactly at a tunable predefined time. Finally, the effectiveness and performance of the proposed IACG law are shown by several simulations with comparative study.

SPIDER on-line data visualization tool

SPIDER (Source for Production of Ion of Deuterium Extracted from Radio Frequency plasma), has been operating in Padova since May 2018, with the aim to test and develop the ITER-scale radio-frequency negative ion source, to study the beam characteristics and to verify the source operation. The source produces more than 500 gigabyte per operational day. Extracting as much information as possible from a set of selected signals (plasma light, voltages and currents of power supplies, cameras, tomography, beam emission spectroscopy, caesium oven parameters and others) during an experimental day allows a more efficient use of the largest neutral beam operating source. The simultaneous visualization of signals, related to pre-defined times of interest arrays, monitors the state of the beam and source features from quite different points of view. However, the time evolution of signals of interest often does not represent the expected format for data analysis. The experimental pulse can be divided in phases called ‘blips’, which correspond to a given experimental configuration typically lasting 40 s. Blips are separated by time periods, required for changing the experiment settings to different configurations. Some punctual information is required for visualization, while derived information is then stored in a relational database for subsequent analysis.The derivation of punctual values was performed offline, with the disadvantage of not being able to derive results of interest during the experiment itself. The new tool derives blip-related information during the pulse, as soon as required data have been stored in the pulse file. The availability of such tool represents a big improvement in the exploitation of the scientific results of SPIDER that can be used in this way during the experimental session itself. Furthermore new features are being developed regarding the addition of other signals including secondary ones and the access to the database from multiple platforms.

Finite element analysis criteria for composite steel decking concrete slabs subjected to fire

In composite steel decking concrete slabs, fire design has to be made according to EN 1994-1-2. However, its procedures are questionable by many references. This is due to the divergence between full-scale experimental research methodologies and numerical studies with different analysis criteria, producing different conclusions. This research sought to numerically study the fire performance of composite steel decking concrete slabs according to two criteria (C): C1, assuming the same temperature field in the cross section, corresponding to a pre-defined ISO 834 fire rating of 30, 45, 60, 90, 120, 150 and 180 min, and an applied load increasing over time; and C2, assuming the increasing temperature field (slab is heated following ISO 834 fire curve) and a constant load over time applied to the slab. C1 allows to define the ultimate load for each pre-defined time of ISO 834 fire curve, while C2 the thermo-physical-mechanical effects. For the parametric calibration of the numerical models, 12 full-scale slabs were tested. 6 slabs under four-point bending test for mechanical parameter definition. Other 6 slabs for fire testing according to ISO 834 fire curve, for thermal and thermomechanical parameter definition. It was clearly noticed that current requirements of the standard are based on criterion C1, as it presented results that are close to the simple flexural theory. However, C1 does not allow defining increase in stresses produced by heating, which is noted only in C2. In C2 it was possible to identify the concrete cracks and detachment of the decking. In some cases, the concrete stresses produced in C2 were opposite to those shown in C1. It is understood that C2 shows more realistic results, but generates greater complexity and processing time for defining the ultimate load for each ISO 834 fire curve time.

Population pharmacokinetics of benznidazole in neonates, infants and children using a new pediatric formulation.

There is a major need for information on pharmacokinetics (PK) of benznidazole (BNZ) in children with Chagas disease (CD). We conducted a multicentre population PK, safety and efficacy study in children, infants and neonates with CD treated with BNZ (formulated in 100 mg tablets or 12.5 mg dispersible tablets, developed by the pharmaceutical company LAFEPE, in a collaboration with DNDi). 81 children 0-12 years old were enrolled at 5 pediatric centers in Argentina. Diagnosis of T. cruzi infection was confirmed by direct microscopic examination, or at least two positive conventional serological tests. Subject enrolment was stratified by age: newborns to 2 years (minimum of 10 newborns) and >2-12 years. BNZ 7.5 mg/kg/d was administered in two daily doses for 60 days. Five blood samples per child were obtained at random times within pre-defined time windows at Day 0 at 2-5 h post-dose; during steady state, one sample at Day 7 and at Day 30; and two samples at 12-24 h after final BNZ dose at Day 60. The primary efficacy endpoint was parasitological clearance by qualitative PCR at the end of treatment. Forty-one (51%) patients were under 2 years of age (including 14 newborns <1 month of age). Median age at enrolment was 22 months (mean: 43.2; interquartile range (IQR) 7-72 months). The median measured BNZ Cmax was 8.32 mg/L (IQR 5.95-11.8; range 1.79-19.38). Median observed BNZ Cmin (trough) concentration was 2 mg/L (IQR 1.25-3.77; range 0.14-7.08). Overall median simulated Css was 6.3 mg/L (IQR 4.7-8.5 mg/L). CL/F increased quickly during the first month of postnatal life and reached adult levels after approximately 10 years of age. Negative qPCR was observed at the end of treatment in all 76 patients who completed the treatment. Five patients discontinued treatment (3 due to AEs and 2 due to lack of compliance). We observed lower BNZ plasma concentrations in infants and children than those previously reported in adults treated with comparable mg/kg doses. Despite these lower concentrations, pediatric treatment was well tolerated and universally effective, with a high response rate and infrequent, mild AEs. Registered in clinicaltrials.gov #NCT01549236.

Transnasal Neuro-Prolozone for the Management of Trigeminal Neuralgia; Dramatic and Long-Term Relief of a Novel Technique

We report two cases of trigeminal neuralgia, dramatically relieved with transnasal neuro- prolozone infiltration of the sphenopalatine ganglion. To be mentioned, we are the first to describe this technique in the treatment of trigeminal neuralgia. The two cases had a history of trigeminal neuralgia for more than 2 years, refractory to pharmacological treatment. Case one is a 63 year-old female, with a 5-year history of trigeminal neuralgia. This patient reported a history of hypertension and atrial fibrillation. The second patient, a 33 year-old male, had a 2-year history of trigeminal neuralgia, and a reported history of type-1 diabetes and ischemic heart disease (IHD). No side effects were reported, along the 6-month follow- up period. The Penn Facial Pain Scale Revised (Penn-FPS-R) was conducted to assess pain interference with the quality of life in the included patients, 1-week before injection, 5 minutes, 15 minutes, one week, 4 weeks and 6 months after injection. The patients’ satisfaction and pain intensity were assessed using the 11-point numeric rating scale (NRS) at the pre-defined time points. The two cases reported long-term improvement, regarding pain intensity and quality of life. In conclusion, transnasal neuro-prolozone infiltration is emerging as an effective, long-term and immediate-acting treatment modality for mitigating the burden of trigeminal neuralgia.