Interval Delay Research Articles

Dissipative analysis for high speed train systems via looped-functional and relaxed condition methods

This study proposes new approaches for the dissipative analysis issue of high-speed train systems. First, an improved boundary circulatory functional approach is introduced for constructing a weak Lyapunov-Krasovskii functional, which can fully excavate some intrinsic relationships between sampling interval and time delay. Based on the looped-functional tactics and recombinant technology, the constraint conditions are further relaxed for obtaining new theoretical results. Second, by using resultful integral inequalities and correlation analysis approaches, several relaxed criteria are established with respect to the asymptotical stable of the considered sampled-data systems. Third, a new reliable memory sampling controller is designed under the desired dissipative performance. Finally, numerical experiments on high-speed trains on the Shinkansen in Japan illustrate the importance of theoretical results.

Synchronization of singular complex networks with time-varying delay via pinning control and linear feedback control

Abstract In this paper, the problem on synchronization is investigated for singular complex networks with time-varying delay via pinning control and linear feedback control. Together with some Lyapunov–Krasovskii functions and effective mathematical techniques, the variation interval of the time delay is divided into several subintervals, several conditions are derived to guarantee a class of singular complex networks with time-varying delay to be synchronized. Finally, examples are given to illustrate the effectiveness of the proposed methods.

The Association Between Antibiotic Delay Intervals and Hospital Mortality Among Patients Treated in the Emergency Department for Suspected Sepsis.

Rapid delivery of antibiotics is a cornerstone of sepsis therapy, although time targets for specific components of antibiotic delivery are unknown. We quantified time intervals comprising the task of antibiotic delivery and evaluated the association between interval delays and hospital mortality among patients treated in the emergency department for suspected sepsis. Retrospective cohort. Twelve hospitals in Southeastern United States from 2014 to 2017. Twenty-four thousand ninety-three encounters among 20,026 adults with suspected sepsis in 12 emergency departments. We divided antibiotic administration into two intervals: time from emergency department triage to antibiotic order (recognition delay) and time from antibiotic order to infusion (administration delay). We used generalized linear mixed models to evaluate associations between these intervals and hospital mortality. Median time from emergency department triage to antibiotic administration was 3.4 hours (interquartile range, 2.0-6.0 hr), separated into a median recognition delay (time from emergency department triage to antibiotic order) of 2.7 hours(interquartile range, 1.5-4.7 hr) and median administration delay (time from antibiotic order to infusion) of 0.6 hours (0.3-1.2 hr). Adjusting for other risk factors, both recognition delay and administration delay were associated with mortality, but pairwise comparison with a no-delay reference group was not significant for up to 6 hours of recognition delay or up to 1.5 hours of administration delay. Both recognition delays and administration delays were associated with increased hospital mortality, but only for longer delays. These results suggest that both metrics may be important to measure and improve for patients with suspected sepsis but do not support targets less than 1 hour.

Development of a Model to Estimate the Association Between Delay in Cancer Treatment and Local Tumor Control and Risk of Metastases

The coronavirus disease 2019 (COVID-19) pandemic has led to treatment delays for many patients with cancer. While published guidelines provide suggestions on which cases are appropriate for treatment delay, there are no good quantitative estimates on the association of delays with tumor control or risk of new metastases. To develop a simplified mathematical model of tumor growth, control, and new metastases for cancers with varying doubling times and metastatic potential and to estimate tumor control probability (TCP) and metastases risk as a function of treatment delay interval. This decision analytical model describes a quantitative model for 3 tumors (ie, head and neck, colorectal, and non-small cell lung cancers). Using accepted ranges of tumor doubling times and metastatic development from the clinical literature from 2001 to 2020, estimates of tumor growth, TCP, and new metastases were analyzed for various treatment delay intervals. Risk estimates for potential decreases in local TCP and increases in new metastases with each interval of treatment delay. For fast-growing head and neck tumors with a 2-month treatment delay, there was an estimated 4.8% (95% CI, 3.4%-6.4%) increase in local tumor control risk and a 0.49% (0.47%-0.51%) increase in new distal metastases risk. A 6-month delay was associated with an estimated 21.3% (13.4-30.4) increase in local tumor control risk and a 6.0% (5.2-6.8) increase in distal metastases risk. For intermediate-growing colorectal tumors, there was a 2.1% (0.7%-3.5%) increase in local tumor control risk and a 2.7% (2.6%-2.8%) increase in distal metastases risk at 2 months and a 7.6% (2.2%-14.2%) increase in local tumor control risk and a 24.7% (21.9%-27.8%) increase in distal metastases risk at 6 months. For slower-growing lung tumors, there was a 1.2% (0.0%-2.8%) increase in local tumor control risk and a 0.19% (0.18%-0.20%) increase in distal metastases risk at 2 months, and a 4.3% (0.0%-10.6%) increase in local tumor control risk and a 1.9% (1.6%-2.2%) increase in distal metastases risk at 6 months. This study proposed a model to quantify the association of treatment delays with local tumor control and risk of new metastases. The detrimental associations were greatest for tumors with faster rates of proliferation and metastasis. The associations were smaller, but still substantial, for slower-growing tumors.

A qualitative exploratory study of delay in the presentation of gastrointestinal cancer

Introduction:Patients with gastrointestinal (GI) cancers often present late in the advanced stages, due to various reasons and may experience delays in treatment. Hence, we have attempted to find the factors leading to this delay.Methods:This was an exploratory qualitative study, in a tertiary care hospital, including 20 patients with advanced GI cancers. They were interviewed to assess the reasons for delays in presentation, diagnosis and treatment, and the factors were analysed based on the interval of delay and the cause.Results:This study found that there was an interval of delay of 8 months from the onset of symptoms till primary treatment, more than half of which occurred in the pre-hospital phase (56.4%). We classified the causes for the delay into different intervals such as the appraisal interval, health-seeking interval, diagnostic interval and the pre-treatment interval. Lapses at the individual, societal and institutional level lead to the delay. The major causes included ignorance, substance abuse, poverty, social stigma, vague symptoms and missed diagnosis, miscommunication, resource constrain, very poor doctor-patient ratio and delay in investigation and treatment.Conclusion:This study noted a significant delay in the treatment of patients with advanced gastrointestinal cancers. Reasons for delay have been noted at various levels. Further action based on this study, at the community and hospital level could potentially reduce the delay and result in better survival and improved quality of life.

Synchronization of Coupled Nonlinear Systems via Bidirectional Sampled-Data Couplings with Delay

Abstract This paper deals with the synchronization problem of two nonlinear systems via bidirectional sampled-data couplings with delay. In particular, we consider the synchronization problems for the following two cases: (a) output-delay systems with sampled-data coupling, (b) sampled-data systems with transmission delay. First, we derive a sufficient condition for synchronization in the first case. The obtained condition clarifies the relationship among the sampling interval, coupling strength, and time delay to achieve synchronization. After that, we show that the synchronization condition for the second case is the same as that of the first case if the time delay is constant. Numerical simulations illustrate the validity of the obtained results.

Identifying Delay Time of Detonator for a Millisecond Blasting

Based on wavelet transform, the blasting vibration signals are analyzed here. For millisecond blasting, the blasting effect is mostly affected by the actual delay time. Local characteristics of the analyzed signals could be highlighted by the wavelet transform. The simultaneous initiation of large explosive quantity could be avoided by the use of multistage detonators, while the vibration resistance effect could be better. For the same level of detonator segment, the larger the arranged time interval, the less the possibility of initiation at the same time, which is not conducive to the vibration resistance. Therefore, it is suggested to use high‐level detonators with detonating cord or high‐precision digital electronic detonators to minimize the initiation error. Furthermore, by identifying the delay time using wavelet transform, the interval delay time of different detonator segments could be obtained. Moreover, the nominal delay time, actual delay time, and interval delay time are further compared and analyzed. It is suggested that the millisecond delay series of detonators should be selected in the whole section blasting, and the segment should be jumped as much as possible, so as to increase the secondary breakage time. Detonators with longer interval delay time should be avoided to the full.

Abstract 297: Identifying Optimization Targets in 911 Dispatch Workflows for Out-of-hospital Cardiac Arrest Management

Introduction: Dispatch processes for prehospital management of out-of-hospital cardiac arrest (OHCA) vary greatly by region, and so do the barriers and facilitators of rapid time-to-first-treatment within those systems. In order to optimize local OHCA response, we sought to identify improvement targets by tracking time intervals during OHCA 911 calls and evaluating associated barriers and facilitators to timely OHCA prehospital care delivery. Methods: We developed a data abstraction tool to collect quantitative and qualitative data regarding key events in a random sample of 23 of emergency medical services (EMS)-confirmed, second-party, non-traumatic, non-overdose, non-facility adult OHCAs occurring prior to first responder arrival from November 2017 to November 2019 in Washtenaw County, Michigan. Trained abstractors double reviewed calls. We calculated descriptive statistics of key event times to summarize a timeline of care and evaluated qualitative data using thematic analysis to assess event intervals. Results: Based on quantitative and qualitative analyses, we created a timeline with summary data of dispatcher OHCA response based on an aggregate of 23 calls to 911 dispatch (see Figure 1). Data abstractors identified two intervals-of-interest as containing barriers to optimizing time-to-first treatment: 1) time between the first report of abnormal breathing and call taker statement of CPR need (Interval 1), and 2) time from patient positioning to the first compression instruction (Interval 2). Qualitative data suggested that these interval delays were a result of extensive efforts on the part of the call taker to reconfirm breathing status in particular. Additional barriers, such as the callers misunderstanding instruction, and on-scene physical limitations, were also identified. Conclusions: We identified two primary time intervals to target for improvement as well as barriers present in our local 911 system. These data may serve as a foundation to develop targeted interventions to optimize local systems of care for 911 dispatch workflows. Figure 1

Network-based reference model tracking for vehicle turning with event-triggered transmission and interval communication delays

This paper deals with the network-based modelling and reference model tracking control of four-wheel-independent-drive electric vehicles for turning purpose. First, a reference model is designed by adjusting its input to characterise the expected neutral turning of the vehicle. By considering event-triggered transmission and interval communication delays, the network-based tracking control system attaining vehicle turning is modelled as an interval input delay system, where the input delay is bounded by the bounds of communication delays and the sampling period. Second, a new delay-dependent bounded real lemma with less conservatism is derived by proposing a matrix-based binary quadratic convex method, constructing a discontinuous augmented Lyapunov–Krasovskii functional tailored based on second-order Bessel–Legendre inequality, and exploiting the relation among the upper bounds of input delay and interval communication delays, and the sampling period. Third, the network-based tracking controller design result is further established by linear matrix inequalities. Finally, an example is provided to confirm the superiority of the analysis results and the effectiveness of control design.

Stability analysis and output feedback control for stochastic networked systems with multiple communication delays and nonlinearities using fuzzy control technique

This paper addresses the H-infinity Takagi-Sugeno (T-S) fuzzy control for a class of T-S fuzzy discrete networked control systems with random interval communication delays and random sector nonlinearities. Firstly, the T-S fuzzy model is employed to approximate the discrete networked control system and the ℓth-order Rice fading channels model is introduced in the system model. Secondly, the T-S fuzzy dynamic output feedback controller with ℓth-order Rice fading channels output is designed for the T-S fuzzy discrete networked control system. Thirdly, the discrete delay-dependent Lyapunov-Krasovskii functional, stochastic system theory and Bernoulli probability distribution are employed to derive the stability conditions in terms of linear matrix inequalities (LMIs). Compared with previous works, the fading channels in the signal transmission are described clearly by setting the different channels coefficients of the ℓth-order Rice fading channels model. The closed-loop system is exponentially mean-square stable and prescribed H-infinity performance is guaranteed by designing the T-S fuzzy dynamic output feedback controller. The factorizations in the polynomial and the congruence transformation matrices are introduced to solve the LMIs, such that the controller gain matrices are determined. Finally, simulation examples are presented to show the effectiveness of proposed methods.

Distributed Dynamic Self-Triggered Control for Uncertain Complex Networks With Markov Switching Topologies and Random Time-Varying Delay

This paper studies the synchronization of complex networks with probabilistic interval delay and Markov switching topologies by using a novel dynamic self-triggered control (DSTC) scheme. Employing the probability distribution information of the input time-delay, the control protocol is transformed into a new rule with stochastic parameters. Also, a more general case of switching topologies, Markov switching topologies with partial information on transition rate, is discussed. By introducing a free-connection weighting matrix scheme and using the stability theory, a less conservative synchronization result is derived. It is shown by a numerical example that the DSTC method can reduce the sampling frequency apparently, and the tolerable delay upper bound can also be relaxed. In addition, continuous communication and the Zeno-behavior can be avoided.

Evaluation of DTTV Transmission for SFN with Minimum Threshold in Thailand

The digital terrestrial television (DTTV) transmission based on digital video broadcasting-terrestrial second generation (DVB-T2) for a single frequency network (SFN) shall be studied. The DTTV signal performance is very important. Therefore, the performance of DTTV should be studied. SFN is a key factor in DVB-T2 technology due to the benefits of SFN. In order to evaluate the DVB-T2 performance, this research had investigates broadcasting reception threshold of DVB-T2 signal. The experiment was done in a laboratory of Mass Communication Organization of Thailand company, Thailand, and field experiment was done in urban area of Sing Buri, Thailand. The measurement model was set up to measure the the DTTV performance parameter with respected to guard interval delay time of two SFN transmitters. The acceptable result of minimum power, received signal, CNR, MER, and transmission loss are presented. The reliability of the result was validated by using polynomial. The measurement results provided a useful information for optimization and modeling of DTTV broadcasting for SFN system with DVB-T2 in Thailand.

0157 The Relationship Between Reaction Time, Insomnia Severity, Sleepiness, and Dysfunctional Beliefs About Sleep

Abstract Introduction Poor sleep quality has adverse effects ranging from decreased focus to increased work-related injuries. The Perceptual Vigilance Task (PVT), a measure of reaction time (RT) used to assess alertness is commonly used in sleep research. This study focuses on the relationship between dysfunctional sleep-related cognitions (Dysfunctional Beliefs and Attitudes About Sleep Scale [DBAS]), insomnia severity (Insomnia Severity Index [ISI]), and sleepiness (Epworth Sleepiness Scale [ESS]) and their association to PVT RT. Methods 162 participants were recruited from East Carolina University. Inclusion criteria: right-handed adults; exclusion criteria: history of brain injury, seizure disorder, or vision impairment. Age range 18–39 (M = 20.15; SD = 3.01); 81 (49.1%) females. Results ISI was correlated with PVT RT for inter-stimulus interval delay times of 1000ms r(162) = .155, p =.05, 2000ms r(162) = .204, p = .009, 5000ms r(162) =.164, p = .04, and 6000ms r(162) = .181, p = .02. DBAS was correlated with PVT RT for delay times of 2000ms r(162) = .204, p =.021, 3000ms r(162) = .160, p = .04, 4000ms r(162) = .170, p = .03, 6000ms r(162) = .171, p = .030, 7000ms r(162) = .219, p =.005, and 8000ms r(162) = .158 p = .045. ESS was not correlated with PVT. A regression was calculated to predict reaction time at 7000ms delay based on the DBAS (F(1,151) = 2.51, p = .01), with an R2 of .12. Conclusion There is a diminishing association found between insomnia severity and RT during inter-stimulus delay times (>6000ms). Dysfunctional beliefs about sleep correlate with RT through 8000ms delay, eventually predicting RT. Regardless of severity of sleep disturbance, sleep-related bias may affect subjective feelings of wakefulness and objective levels of alertness (e.g., one who believes they are not obtaining sufficient sleep may act accordingly). Support N/A

The stability and accuracy analysis of automatic steering system with time delay

The paper presents a systematic method of stability analysis for automatic steering system involving a time delay and some external disturbances. The analysis focuses on the stability of automatic steering system with increase of the time delay from zero to infinity. Firstly, the structure and dynamic model of automatic steering system are briefly introduced, and PD control algorithm is adopted to further analysis the time delay mechanism of control system of automatic steering system. Then the time delay dynamic models of automatic steering system with PD control algorithm are derived, the time delay stability interval and critical time delay of automatic steering system are calculated by using the generalized Sturm criterion method. Finally, the accuracy of critical time delay calculation by proposed method, and the stability and accuracy of automatic steering system with time delay and external disturbance are illustrated by numerical simulations.

Robust adaptive sliding mode control for discrete singular systems with randomly occurring mixed time-delays under uncertain occurrence probabilities

This paper is concerned with the problem of robust adaptive sliding mode control (RASMC) for discrete singular systems subject to randomly occurring mixed time-delays (ROMTDs) under uncertain occurrence probabilities. The mixed time delays are considered, which are comprised of both the discrete interval delays and infinite distributed delays. Meantime, two random variables obeying the Bernoulli distribution are utilised to depict the phenomena of randomly occurring discrete time-varying delay and distributed time-delay, in which the uncertain occurrence probabilities are modelled by the known scalars. An appropriate sliding surface function is firstly presented. Furthermore, some sufficient criteria via the free weighting matrices idea are obtained to ensure the admissibility of the resultant sliding motion by introducing new Lyapunov-Krasovskii functional. Subsequently, an RASMC law is synthesised to ensure the reachability criterion of pre-designed sliding surface, where an adaptive mechanism is introduced to estimate the related unknown bounds. Finally, the feasibility of the new RASMC strategy is illustrated by a numerical simulation.

On the Delay Interval in Which the Control Delay Systems are Stabilizable

In this paper, we firstly derive some criteria for considered control delay systems to be stabilizable and then get the interval of the control delay, in which the stabilizability of the systems can be kept.

Synchronization of complex networks with time-varying delay of unknown bound via delayed impulsive control

The synchronization problem for complex networks with time-varying delays of unknown bound is investigated in this paper. From the impulsive control point of view, a novel delayed impulsive differential inequality is proposed, where the bounds of time-varying delays in continuous dynamic and discrete dynamic are both unknown. Based on the inequality, a class of delayed impulsive controllers is designed to achieve the synchronization of complex networks, where the restriction between impulses interval and time-varying delays is dropped. A numerical example is presented to illustrate the effectiveness of the obtained results.

Constraining Type Iax supernova progenitor systems with stellar population age dating

ABSTRACT Type Iax supernovae (SNe Iax) are the most common class of peculiar SNe. While they are thought to be thermonuclear white-dwarf (WD) SNe, SNe Iax are observationally similar to, but distinct from SNe Ia. Unlike SNe Ia, where roughly 30 per cent occur in early-type galaxies, only one SN Iax has been discovered in an early-type galaxy, suggesting a relatively short delay time and a distinct progenitor system. Furthermore, one SN Iax progenitor system has been detected in pre-explosion images with its properties consistent with either of two models: a short-lived (<100 Myr) progenitor system consisting of a WD primary and a He-star companion, or a singular Wolf–Rayet progenitor star. Using deep Hubble Space Telescope images of nine nearby SN Iax host galaxies, we measure the properties of stars within 200 pc of the SN position. The ages of local stars, some of which formed with the SN progenitor system, can constrain the time between star formation and SN, known as the delay time. We compare the local stellar properties to synthetic photometry of single-stellar populations, fitting to a range of possible delay times for each SN. With this sample, we uniquely constrain the delay-time distribution for SNe Iax, with a median and 1σ confidence interval delay time of $63_{- 15}^{+ 58} \times 10^{6}$ yr. The measured delay-time distribution provides an excellent constraint on the progenitor system for the class, indicating a preference for a WD progenitor system over a Wolf–Rayet progenitor star.

Improved H-Infinity Hybrid Model Predictive Fault-Tolerant Control for Time-Delayed Batch Processes Against Disturbances

An H-infinity model predictive fault-tolerant control strategy is proposed for multi-phase batch processes with interval delay and actuator failures. First, state variables, state errors and output tracking errors are introduced to establish an extended-state-space switched system model. Then, based on this model, a predictive fault-tolerant control law is designed for tracking the set point by the output that satisfies the requirements of the optimal performance index under input and output constraints. The feasibility conditions for the solvability of the control law are presented in the form of linear matrix inequalities. In addition, the designed switching law is constructed, and the gain of the control law is obtained via the optimization algorithm. This design has several advantages: the output tracking is faster, the tracking performance is superior, and the trace is smoother at the switching time. Finally, through a comparison with traditional methods, the effectiveness and feasibility of this method are demonstrated via injection molding simulation.

Asymptotic Analysis of Linear and Interval Linear Fractional-Order Neutral Delay Differential Systems Described by the Caputo-Fabrizio Derivative

Asymptotic stability of linear and interval linear fractional-order neutral delay differential systems described by the Caputo-Fabrizio (CF) fractional derivatives is investigated. Using Laplace transform, a novel characteristic equation is derived. Stability criteria are established based on an algebraic approach and norm-based criteria are also presented. It is shown that asymptotic stability is ensured for linear fractional-order neutral delay differential systems provided that the underlying stability criterion holds for any delay parameter. In addition, sufficient conditions are derived to ensure the asymptotic stability of interval linear fractional order neutral delay differential systems. Examples are provided to illustrate the effectiveness and applicability of the theoretical results.