Prescribed Time Interval Research Articles

Finite-time decentralized event-triggering non-fragile control for fuzzy neural networks with cyber-attack and energy constraints

In this study, we concerned with non-fragile control problem for T-S fuzzy neural networks (TSFNNs) within finite-time domain under decentralized event-triggered scheme, limited network-bandwidth and cyber-attack. Precisely, the event-triggered mechanism and energy constraints are introduced to mitigate the network traffic and to protect the network resources. To be specific, an event-triggered mechanism relieves the network transmission burden and the sensors which decide the measurement transmissions in accordance with event-triggered scheme. The main intention of this work is to design a decentralized event-triggered scheme and non-fragile controller for ensuring the stochastic finite-time boundedness for the desired TSFNNs with optimal mixed H∞ and passivity performance index within the prescribed time interval. In accordance with Lyapunov–Krasovskii stability theory, an adequate condition in the frame of linear matrix inequalities is established to signify the stochastic stability of the resulting closed-loop TSFNNs. Moreover, the projected gain matrix is characterized by the obtained linear matrix inequalities. At long last, a numerical example is framed to substantiate the effectiveness and superiority of the proposed control strategy.

A Differential Game Model of Opinion Dynamics: Accord and Discord as Nash Equilibria

This paper presents a noncooperative differential (dynamic) game model of opinion dynamics with open-loop information structure. In this game, the agents’ motives are shaped by their expectations of the nature of others’ opinions as well as how susceptible they are to get influenced by others, how stubborn they are, and how quick they are willing to change their opinions on a set of issues in a prescribed time interval. These motives are independently formed by all agents. The existence of a Nash equilibrium in the network means that a collective behavior emerges out of local interaction rules and these individual motives. We prove that a unique Nash equilibrium may exist in the game under quite different circumstances. It may exist not only if there is a harmony of perceptions among the agents of the network, but also when agents have different views about the correlation among issues. The first leads to an accord in the network usually expressed as a partial consensus, and the second to a discord in the form of oscillating opinions. In the case of an accord, the harmony in the network may be in the form of similarity in pairwise conceptions about the issues but may also be an agreement on the status of a “leader” in the network. A Nash equilibrium may fail to exist only if the network is in a state of discord.

Finite-time control of perturbed dynamical systems based on a generalized time transformation approach

We study finite-time control of perturbed dynamical systems based on the time transformation approach. For addressing time-critical applications, where the execution of a control algorithm over a prescribed time interval [0,τ) is necessary with τ being a user-defined convergence time, we introduce a new class of scalar, time-varying gain functions entitled as “generalized finite-time gain functions” that have the capability to convert an original baseline control algorithm into a time-varying one. Based on these generalized finite-time gain functions, in particular, the corresponding “generalized time transformation functions” are obtained and used to transform a resulting algorithm over the prescribed time interval [0,τ) to an equivalent algorithm over the stretched infinite-time interval [0,∞) for stability analysis, where the connection between the generalized finite-time gain functions and their corresponding generalized time transformation functions are investigated in detail. A procedure for designing finite-time control algorithms is further proposed and illustrated by numerical examples showing that the method is applicable to, but not limited to, a class of nonlinear systems as well as multiagent systems. In addition, we show all the conditions on the proposed generalized finite-time gain functions that guarantee the boundedness and convergence of the state and control signals. An application of our theoretical findings to the distributed control of networked multiagent systems problem over a prescribed time interval is also presented.

Creating a More Realistic Idealized Supercell Thunderstorm Evolution via Incorporation of Base-State Environmental Variability

Abstract Convective environments are known to be heterogeneous in both time and space, yet idealized models use fixed base-state environments to simulate storm evolution. Recently, the base-state substitution (BSS) technique was devised to account for environmental variability in a controlled manner while maintaining horizontal homogeneity; BSS involves updating the background environment to reflect a new storm-relative proximity sounding at a prescribed time interval. The study herein sought to assess the ability of BSS to more realistically represent the structure and evolution of an observed supercell thunderstorm in comparison to simulations with fixed base-state environments. An extended dual-Doppler dataset of an intensifying supercell thunderstorm in a varying inflow environment was compared to idealized simulations of the same storm; simulations included those with fixed background environments, as well as a BSS simulation that incorporated environmental variability continuously via tendencies to the base-state variables based on changes in a series of observed soundings. While the simulated supercells were generally more intense than what was measured in the observations, broad trends in reflectivity, vertical velocity, and vertical vorticity were more similar between the observed and BSS-simulated supercell; with a fixed environment, the supercell either shrunk in size and weakened over time, or grew upscale into a larger convective system. Quantitative comparisons examining distributions, areas, and volumes of vertical velocity and vorticity further confirm these differences. Overall, BSS provides a more realistic result, supporting the idea that a series of proximity soundings can sufficiently represent the effects of environmental variability, enhancing accuracy over fixed environments.

Eddy Current Array Inspection of Zlin 142 Fuselage Riveted Joints

Abstract Aircraft fuselage is subject under the influence of many negative factors during its operation. Non-destructive testing methods are primarily used to minimize the possibility of possible failure. For early detection of any anomalies that may occur at aircraft fuselage are used mainly electromagnetic non-destructive testing and evaluation methods. This paper deals with inspection of riveted joints of the fuselage and wings of aircraft Zlin 142. The aircraft manufacturer determines the prescribed time intervals for the inspection of the fuselage. During the inspection, we will try to detect possible cracks and reveal a presence of hidden corrosion. A suitable method for the inspection of these riveted joints is eddy current testing method (ECT). Eddy current testing is one of the widely utilized electromagnetic NDE methods. It works based on an interaction of time-varying electromagnetic field with a conductive structure according to the Faraday’s electromagnetic induction law. This electromagnetic method is suitable for reliable detection of surface and subsurface defects of the riveted joints. Experiments will utilize Olympus OmniScan MX device with presence of ECA module. Eddy current array probes SAB-067-005-032 and SBB-051-150-032 are used, respectively. Harmonic eddy current excitation is used for this purpose.

Nucleation and growth of metal nanoparticles on a planar electrode: A new model based on iso-nucleation-time classes of particles

An assembly of hemispherical particles continuously nucleating on a planar electrode and growing under mixed kinetic-diffusion control is here considered. A model is derived, from the exact boundary integral formulation of the diffusion equation, to predict the overall current evolution, and the radii distribution of particles nucleating within any prescribed time interval. Iso-nucleation-time classes are introduced in the model, grouping particles (almost) simultaneously nucleating over the underlying substrate. The dynamics of particles belonging to a given iso-nucleation-time class are assumed to be identical. By this approximation, hereby referred to as Averaged Class Approximation (ACA), the computation of the average radius of any iso-nucleation-time class is reduced to the solution of an integro-differential equation, parameterized by the nucleation time. An effective computational method is also presented to solve the model equations, giving predictions that fairly well agree with the results of direct multi-particle numerical simulations.

Absorption of polycyclic aromatic hydrocarbons by a highly absorptive polymeric medium

The efficacy of a lightly cross-linked polymeric bead to absorb polycyclic aromatic hydrocarbons (PAHs) from the surface of fresh- and salt-water in a simulated oil-spill scenario was assessed in this study. A layer of PAHs at the water surface was created by first preparing the PAHs in hexane and then carefully spiking this mixture onto the surface of water. Beads were then applied to the surface of the organic phase and the amount of hydrocarbons absorbed by the beads was examined at prescribed time intervals and at different temperatures. Absorption of PAHs into the beads was exhaustive with ∼86 ± 4% being selectively removed from the organic phase by 120 s. First order reaction rates best described the uptake kinetics and absorption rates ranged from 0.0085 (naphthalene) to 0.0325 sˉ1 (dibenzo[a,h]anthracene). Absorption of PAHs into the beads was driven by molecular volume (A3). Uptake rates increased markedly for PAHs with molecular volumes between 130 A3 and 190 A3. Beyond this molecular volume there was no apparent change in the rate of uptake. This study shows that these polymeric beads have a high affinity for PAHs and can be used under various environmental conditions with negligible difference in absorptive efficacy.

An integrated tri-level model for enhancing the resilience of facilities against intentional attacks

It is paramount to enhance the resilience of many facilities that are known to be critical for modern societies and threatened by intentional attacks. For this purpose, it is important to not only protect them before disruptions, but also recover them after disruptions. To deal with this problem, this paper proposes a tri-level model explicitly integrating the decision making on recovery strategies of disrupted facilities with the decision making on protecting facilities from intentional attacks. The facilities studied in this research are assumed to be capacitated and a recovery strategy is considered to include repairing a subset of disrupted facilities and expanding the capacities of a subset of non-interdicted facilities. We are concerned with the defender’s objective of maximizing the resilience of the given set of facilities making profit within a prescribed time interval. To deal with the complexity of solving the proposed tri-level model, the ant colony system algorithm is employed with necessary adaptations.

Optimal initial condition of passive tracers for their maximal mixing in finite time

The efficiency of a fluid mixing device is often limited by fundamental laws and/or design constraints, such that a perfectly homogeneous mixture cannot be obtained in finite time. Here, we address the natural corollary question: Given the best available mixer, what is the optimal initial tracer pattern that leads to the most homogeneous mixture after a prescribed finite time? For ideal passive tracers, we show that this optimal initial condition coincides with the right singular vector (corresponding to the smallest singular value) of a suitably truncated Perron-Frobenius (PF) operator. The truncation of the PF operator is made under the assumption that there is a small length-scale threshold $\ell_\nu$ under which the tracer blobs are considered, for all practical purposes, completely mixed. We demonstrate our results on two examples: a prototypical model known as the sine flow and a direct numerical simulation of two-dimensional turbulence. Evaluating the optimal initial condition through this framework only requires the position of a dense grid of fluid particles at the final instance and their preimages at the initial instance of the prescribed time interval. As such, our framework can be readily applied to flows where such data is available through numerical simulations or experimental measurements.

Phyllotactic regularity requires the Paf1 complex in Arabidopsis.

In plants, aerial organs are initiated at stereotyped intervals, both spatially (every 137° in a pattern called phyllotaxis) and temporally (at prescribed time intervals called plastochrons). To investigate the molecular basis of such regularity, mutants with altered architecture have been isolated. However, most of them only exhibit plastochron defects and/or produce a new, albeit equally reproducible, phyllotactic pattern. This leaves open the question of a molecular control of phyllotaxis regularity. Here, we show that phyllotaxis regularity depends on the function of VIP proteins, components of the RNA polymerase II-associated factor 1 complex (Paf1c). Divergence angles between successive organs along the stem exhibited increased variance in vip3-1 and vip3-2 compared with the wild type, in two different growth conditions. Similar results were obtained with the weak vip3-6 allele and in vip6, a mutant for another Paf1c subunit. Mathematical analysis confirmed that these defects could not be explained solely by plastochron defects. Instead, increased variance in phyllotaxis in vip3 was observed at the meristem and related to defects in spatial patterns of auxin activity. Thus, the regularity of spatial, auxin-dependent, patterning at the meristem requires Paf1c.

Predicting the Formation of Haloacetonitriles and Haloacetamides by Simulated Distribution System Tests

Unintended chemical reactions between disinfectants and natural organic matter (NOM) or anthropogenic compounds in natural waters result in the formation of disinfection by-products (DBPs) during drinking water treatment. To date, numerous groups of disinfection by-products have been identified in drinking water, some of which are suspected to be of public health importance and thus are regulated in the water industry. Recent studies have suggested that some unregulated nitrogen-containing DBPs, such as haloacetonitriles (HANs) and haloacetamides (HAcAms), may have greater toxicity than the currently regulated groups (trihalomethanes, THMs, and haloacetic acids, HAAs). There is only sparse information on the behaviour of the HANs and HAcAms in distribution systems. It is however known that HANs can be hydrolysed to the HAcAms, which in turn can hydrolyse to form dihaloacetic acids (DHAAs).Simulated distribution systems tests (SDS) have been successfully applied to predict the formation of THMs and HAAs using a simple and inexpensive lab-based technique, and have been recommended by the US Environmental Protection Agency (EPA) to American water utilities for collecting information about the levels of DBPs occurring in their distribution systems. SDS tests aim to simulate the water quality, disinfectant residuals, and water ages of a real distribution system, allowing easy sampling at prescribed time intervals for analysis of DBP formation. These tests are also a useful tool for considering the impact of potential changes to distribution practices, such as switching from chlorination to chloramination, for example.Therefore, a sampling survey was conducted in four surface water treatment plants in the UK to examine the formation of HANs and HAcAms in both real distribution systems and SDS tests. The samples were extracted using liquid-liquid extraction and analysed by gas chromatography with electron capture detection (GC-ECD). The research sought to determine whether SDS can be a useful predictive tool for HANs and HAcAms in distribution systems and what levels of prediction error are to be expected.

Finite-time filtering for T–S fuzzy jump neural networks with sector-bounded activation functions

This paper is concerned with the problems of finite-time filter analysis and design for discrete time-delay neural networks with Markovian jump parameters and sector-bounded activation functions represented by Takagi–Sugeno fuzzy model. Firstly, a sufficient admissibility criterion is presented to guarantee that the augmented fuzzy jump neural network without parameter uncertainties is stochastically finite-time bounded in a prescribed time interval. From the admissibility criterion obtained, a sufficient condition on stochastic finite-time boundedness is provided for the augmented fuzzy jump neural networks. Then, a sufficient criterion to design a finite-time fuzzy filter is presented with uncertain parameters and Markovian jumps for discrete time-delay fuzzy neural networks. Moreover, conditions on stochastic finite-time stability are also established for nominal and uncertain delayed fuzzy jump neural networks without the presence of external disturbance. All criteria obtained can be represented as the form of linear matrix inequalities. Finally, numerical examples are given to illustrate the effectiveness of the obtained results.

Color Stability of Heat-cure Acrylic Resin Subjected to Simulated Short-term Immersion in Fast-acting Denture Cleansers.

Background:Regular usage of denture cleansers is recommended in complete denture wearers for effective plaque control, and these cleansers alter the physical properties of acrylic resin over a period of time. Thus, an in vitro study was carried out to assess the effect of denture cleansers on the color stability of heat-cure denture base resin.Aim:The aim of the present study was to evaluate the effect of commercially available fast-acting denture cleansers on the color stability of heat-cure denture base resin at different time intervals.Materials and Methods:Thirty-six heat-cure acrylic resin (Ivoclar Triplex Hot-V) specimens are randomly allocated into four groups – Group A (distilled water as control); Group B (polident – 3 min); Group C (fixodent scope plus); and Group D (stain away plus) comprising of nine samples each. After recording the baseline values, the specimens were immersed in their respective cleansing solutions for a prescribed time interval. This procedure was repeated daily, and the color change (ΔE) was evaluated after 90 and 180 days interval using a colorimeter in a standard “Commission International de l'Eclairage” color system.Statistical Analysis Used:Paired t-test and Dunnett's T3 test.Results:All the groups exhibited a variable color change (ΔE) for an immersion period of 90 days. However, significant color differences (P = 0.001) were noticed among the test groups after 180 days.Conclusion:The color change of denture base resin was greater for Group D followed by Groups B, C, and A respectively after 180 days of immersion. The ΔE values of all test groups increased with time.

The maximum earthquake in future T years: Checking by a real catalog

The studies of disaster statistics are being largely carried out in recent decades. Some recent achievements in the field can be found in Pisarenko and Rodkin (2010). An important aspect in the seismic risk assessment is the using historical earthquake catalogs and the combining historical data with instrumental ones since historical catalogs cover very long time periods and can improve seismic statistics in the higher magnitude domain considerably. We suggest the new statistical technique for this purpose and apply it to two historical Japan catalogs and the instrumental JMA catalog. The main focus of these approaches is on the occurrence of disasters of extreme sizes as the most important ones from practical point of view. Our method of statistical analysis of the size distribution in the uppermost range of extremely rare events was suggested, based on maximum size Mmax(τ) (e.g. earthquake energy, ground acceleration caused by earthquake, victims and economic losses from natural catastrophes, etc.) that will occur in a prescribed time interval τ. A new approach to the problem discrete data that we called “the magnitude spreading” is suggested. This method reduces discrete random value to continuous ones by addition a small uniformly distributed random components. We analyze this method in details and apply it to verification of parameters derived from two historical catalogs: the Usami earthquake catalog (599–1884) and the Utsu catalog (1885–1925). We compare their parameters with ones derived from the instrumental JMA catalog (1926–2014). The results of this verification are following: The Usami catalog is incompatible with the instrumental one, whereas parameters estimated from the Utsu catalog are statistically compatible in the higher magnitude domain with sample of Mmax(τ) derived from the JMA catalog.

Effectiveness of Pre-and Post-Archwire Insertion Acetaminophen Vs. Non-Pharmacologic Management of Pain During Orthodontic Tooth Movement

Introduction: Some patients undergoing orthodontic treatment perceive discomfort at levels that may negatively impact their feelings about their treatment and decrease their compliance. The purpose of this investigation was to study the effectiveness of either pre- or post-archwire insertion acetaminophen versus a placebo or telephone call in controlling discomfort. Materials/Methods: A total of 120 patients, aged 12 to 18 years, undergoing fixed comprehensive orthodontic treatment were ran - domly assigned to one of six experimental groups: (1) 600 mg acetaminophen pre-treatment, 600 mg acetaminophen post-treatment; (2) lactose placebo pre-treatment, 600 mg acetaminophen post-treatment; (3) 600 mg acetaminophen pre-treatment, lactose placebo post-treatment; (4) lactose placebo pre-treatment and post-treatment; (5) courtesy phone call pre-treatment, courtesy phone call post- treatment; (6) no courtesy phone call pre-treatment or post-treatment. Medication group subjects were instructed to take the oral medications at prescribed time intervals before and after initial archwire insertion. The patient's level of discomfort was assessed using a 100mm visual analogue scale (VAS) approximately 1 hour prior to initial archwire placement and at 3, 7, 19, 24, 31, and 48 hours after archwire placement. Results: The peak level of mild to moderate discomfort occurred 19 hours after archwire placement and the differences in VAS scores between the six groups and gender were not statistically significant. Conclusions: All of the interventions were equally effective in controlling the pain following initial orthodontic appliance placement, indicating a relatively low level of pain.

Localization of flow structures using -norm optimization

AbstractStability theory based on a variational principle and finite-time direct-adjoint optimization commonly relies on the kinetic perturbation energy density ${E}_{1} (t)= (1/ {V}_{\Omega } )\int \nolimits _{\Omega } e(\boldsymbol{x}, t)\hspace{0.167em} \mathrm{d} \Omega $ (where $e(\boldsymbol{x}, t)= \vert \boldsymbol{u}{\vert }^{2} / 2$) as a measure of disturbance size. This type of optimization typically yields optimal perturbations that are global in the fluid domain $\Omega $ of volume ${V}_{\Omega } $. This paper explores the use of $p$-norms in determining optimal perturbations for ‘energy’ growth over prescribed time intervals of length $T$. For $p= 1$ the traditional energy-based stability analysis is recovered, while for large $p\gg 1$, localization of the optimal perturbations is observed which identifies confined regions, or ‘hotspots’, in the domain where significant energy growth can be expected. In addition, the $p$-norm optimization yields insight into the role and significance of various regions of the flow regarding the overall energy dynamics. As a canonical example, we choose to solve the $\infty $-norm optimal perturbation problem for the simple case of two-dimensional channel flow. For such a configuration, several solutions branches emerge, each of them identifying a different energy production zone in the flow: either the centre or the walls of the domain. We study several scenarios (involving centre or wall perturbations) leading to localized energy production for different optimization time intervals. Our investigation reveals that even for this simple two-dimensional channel flow, the mechanism for the production of a highly energetic and localized perturbation is not unique in time. We show that wall perturbations are optimal (with respect to the $\infty $-norm) for relatively short and long times, while the centre perturbations are preferred for very short and intermediate times. The developed $p$-norm framework is intended to facilitate worst-case analysis of shear flows and to identify localized regions supporting dominant energy growth.

Abstract WP409: Hematoma Expansion After Spontaneous Intracerebral Hemorrhage in Children

Objective: Hematoma expansion and its predictors like the “spot sign” are important research areas in adults with primary (hypertensive) intracerebral hemorrhage (ICH), but are rarely studied in secondary ICH. At one center, in adults with ICH due to brain arteriovenous malformation (AVM), aneurysm, or tumor, significant hematoma expansion (>33%) occurred in 6/30 (20%) within 24 hours. In children, the frequency of hematoma expansion and the appropriate timing of follow-up neuroimaging are unknown. We assessed the frequency and extent of hematoma expansion in children with non-traumatic ICH. Methods: From 2007 to 2012, 73 children with spontaneous ICH were enrolled in a three-center prospective study (≥37 weeks gestation-17 years). Inclusion for this sub-study: 2 head CTs obtained for clinical indications within 48 hours after presentation with ICH (28 children). Exclusion: Surgical evacuation of hematoma before 2 nd CT was obtained (2 children), IVH only (7 children), neonates <29 days old (20 children). Hematoma volume was assessed via manual volumetric analysis. Results: Of 73 children, 25 (34%) met all inclusion and exclusion criteria. Median age was 9.0 years, interquartile range (IQR) 2.1-14.1. Median time from symptom onset to first CT was 9.4 hours (IQR 4.5-20). ICH was due to coagulopathy or vascular cause in 22/25 children (88%). Median baseline ICH volume was 22.2mL (range 2-86mL). Hematoma expansion occurred in 7/25 (28%) with 2 head CTs. Median ICH volume expansion was 4mL (range 0.1-12mL), 32% (range 2-58%) of baseline ICH volume. Three had significant (>33%) expansion; all had coagulopathy or vascular etiologies of ICH. As expected, children with 2 head CTs had larger baseline ICH volumes (p=0.05) and were more likely to receive treatment for elevated intracranial pressure (ICP) (p=0.001) compared to children with ICH who had fewer than 2 head CTs within 48 hours. Conclusion: Hematoma expansion occurred in 28% of children with clinical concern for hematoma growth and was >33% in 12%. Repeat CT should be considered in those with large ICH and increased ICP. Head CTs were not obtained at prescribed time intervals; research CTs without clear benefit are not feasible in children.

The sinks of dissolved inorganic nitrogen in surface water of wetland mesocosms

The transport of dissolved inorganic nitrogen in wetlands was investigated in the Yeyahu National Preserve of Beijing, China, from July to December 2011. Stable isotope of nitrogen (15N) as NH4+ was added to experimental mesocosms vegetated by seven common wetland plants. The 15N abundance in soil and various plant parts were measured at prescribed time intervals during the 49-day experimental period. Rapid 15N enrichments were found in soil and aquatic plants during the first sampling event at day 3 and typically increased linearly during the experimental period. Highest 15N enrichment was found in submerged plants, followed by emergent plants and soil. No differences in δ15N values were found among leaves and stems of all submerged plants (Potamogeton pusillus, Potamogeton perfoliatus, Najas marina, Ceratophyllum demersum), suggesting that these plant structures are equally effective in nitrogen assimilation. The roots of P. perfoliatus displayed the lowest enrichment compared to the stems and leaves. Such results indicate that submerged plant roots may have a relatively weak role in nitrogen assimilation. The two emergent plants (Phragmites australis and Typha orientalis) showed no differences in δ15N values among all plant parts, suggesting rapid translocation of nitrogen from roots to other portions. This experiment demonstrates that wetland soil and plant stems and leaves are major sinks for dissolved nitrogen from the surface water and provides valuable insight into nitrogen retention and transport pathways in various wetland plants.

How to Visualize the K-root Name Server

We present a novel paradigm to visualize the evolution of the service provided by one of the most popular root name servers, called K-root, operated by the RIPE Network Coordination Centre (RIPE NCC) and distributed in several locations (instances) worldwide. Our approach can be used to either monitor what happened during a prescribed time interval or observe the status of the service in near real-time. We visualize how and when the clients of K-root migrate from one instance to another, how the workload associated with each instance changes over time, and what are the instances that contribute to offer the service to a selected Internet Service Provider. In addition, the visualization aims at distinguishing usual from unusual operational patterns. This helps not only to improve the quality of the service but also to spot security-related issues and to investigate unexpected routing changes.

The Development of an Obstetric Triage Acuity Tool

The purpose of this article is to describe the journey a multicampus hospital system took to improve the obstetric triage process. A review of literature revealed no current comprehensive obstetric acuity tool, and thus our team developed a tool with a patient flow process, revised and updated triage nurse competencies, and then educated the nurses about the new tool and process. Data were collected to assess the functionality of the new process in assigning acuity upon patient arrival, conveying appropriate acuities based on patient complaints, and initiating the medical screening examination, all within prescribed time intervals. Initially data indicated that processes were still not optimal, and re-education was provided for all triage nurses. This improved all data points. The result of this QI project is that our patients are now seen based on their acuity within designated time frames.