Journal articles: 'System Delays'

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He, Ping, and Tao Fan. "Delay-independent stabilization of nonlinear systems with multiple time-delays and its application in chaos synchronization of Rössler system." International Journal of Intelligent Computing and Cybernetics 9, no. 2 (June 13, 2016): 205–16. http://dx.doi.org/10.1108/ijicc-02-2016-0008.

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Purpose – The purpose of this paper is with delay-independent stabilization of nonlinear systems with multiple time-delays and its application in chaos synchronization of Rössler system. Design/methodology/approach – Based on linear matrix inequality and algebra Riccati matrix equation, the stabilization result is derived to guarantee asymptotically stable and applicated in chaos synchronization of Rössler chaotic system with multiple time-delays. Findings – A controller is designed and added to the nonlinear system with multiple time-delays. The stability of the nonlinear system at its zero equilibrium point is guaranteed by applying the appropriate controller signal based on linear matrix inequality and algebra Riccati matrix equation scheme. Another effective controller is also designed for the global asymptotic synchronization on the Rössler system based on the structure of delay-independent stabilization of nonlinear systems with multiple time-delays. Numerical simulations are demonstrated to verify the effectiveness of the proposed controller scheme. Originality/value – The introduced approach is interesting for delay-independent stabilization of nonlinear systems with multiple time-delays and its application in chaos synchronization of Rössler system.

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BAUER, PETER H., MIHAIL L. SICHITIU, and KAMAL PREMARATNE. "QUEUE CONTROL UNDER TIME-VARIANT DELAYS: A DISCRETE TIME SYSTEM APPROACH." Journal of Circuits, Systems and Computers 11, no. 02 (April 2002): 187–211. http://dx.doi.org/10.1142/s0218126602000380.

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This paper introduces a discrete time model for time-variant delays and investigates the very nature of such delays. It is shown that a linear system-delay interface is a system theoretic necessity for the construction of composite linear systems with time-variant delays. Based on this analysis, two interfaces of particular importance are presented and used to obtain new, simple to check stability results for queue control systems. The relevance of the presented modeling and stability results on queue control systems to QoS control in modern communication networks is illustrated via several examples.

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Klamka, Jerzy. "Stochastic Controllability of Linear Systems With State Delays." International Journal of Applied Mathematics and Computer Science 17, no. 1 (March 1, 2007): 5–13. http://dx.doi.org/10.2478/v10006-007-0001-8.

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Stochastic Controllability of Linear Systems With State DelaysA class of finite-dimensional stationary dynamic control systems described by linear stochastic ordinary differential state equations with a single point delay in the state variables is considered. Using a theorem and methods adopted directly from deterministic controllability problems, necessary and sufficient conditions for various kinds of stochastic relative controllability are formulated and proved. It will be demonstrated that under suitable assumptions the relative controllability of an associated deterministic linear dynamic system is equivalent to the stochastic relative exact controllability and the stochastic relative approximate controllability of the original linear stochastic dynamic system. Some remarks and comments on the existing results for the controllability of linear dynamic systems with delays are also presented. Finally, a minimum energy control problem for a stochastic dynamic system is formulated and solved.

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Yang, Xianqiang, Weili Xiong, Zeyuan Wang, and Xin Liu. "Parameter identification of nonlinear multirate time-delay system with uncertain output delays." Transactions of the Institute of Measurement and Control 40, no. 12 (October 16, 2017): 3498–506. http://dx.doi.org/10.1177/0142331217733326.

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The joint parameter and time-delay estimation problems for a class of nonlinear multirate time-delay system with uncertain output delays are addressed in this paper. The practical process typically has time-delay properties and the process data are often multirate, sampled with output data inevitably corrupted by uncertain delays. The linear parameter varying (LPV) finite impulse response (FIR) multirate time-delay model is initially built to describe the considered system. The problems of over-parameterization and the existence of both continuous model parameters and discrete time-delays have made the conventional maximum likelihood difficult to solve the considered problems. In order to handle these problems, the joint parameter and time-delay estimation for the LPV FIR multirate time-delay model are formulated in the expectation-maximization scheme, and the algorithm to estimate the model parameters and time-delays is derived, simultaneously based on multirate process data. The efficacy of the proposed method is verified through a numerical simulation and a practical chemical plant.

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Garcia-Lozano, Hiram, and Vladimir L. Kharitonov. "Lyapunov Matrices for Time Delay System with Commensurate Delays." IFAC Proceedings Volumes 37, no. 21 (December 2004): 91–95. http://dx.doi.org/10.1016/s1474-6670(17)30449-4.

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Jiang, Zhichao, and Yanfen Guo. "Hopf Bifurcation and Stability Crossing Curve in a Planktonic Resource–Consumer System with Double Delays." International Journal of Bifurcation and Chaos 30, no. 13 (October 2020): 2050190. http://dx.doi.org/10.1142/s0218127420501904.

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In this paper, a planktonic resource–consumer system with two delays is investigated and the coefficients depend on [Formula: see text] one of the two delays. Firstly, the property of solution and the existence of equilibrium are given. The dynamical analysis of the system including stability and Hopf bifurcation by using the delays as parameters is carried out. Both the single delay and two delays can cause the system to produce Hopf bifurcation and the stable switching phenomena may exist. Furthermore, using the crossing curve methods, we obtain the stable changes of equilibrium in two-delay parameter plane, which generalizes the results of the system that the coefficients do not depend on delay. Furthermore, the numerical simulation results show that the theoretical analyses are correct when the delays change.

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Utomo Dwi Hatmoko, Jati, Hery Priyono, Mochamad Agung Wibowo, and Riqi Radian Khasani. "Developing a Prototype of Early Warning System of Delay Risks for Public Projects (EWaSDRiP)." MATEC Web of Conferences 159 (2018): 01015. http://dx.doi.org/10.1051/matecconf/201815901015.

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Delays may occur during pre-construction or construction phases, or both. The aim of this research is to develop a prototype of an early warning system of delay risks for public projects in pre-construction phase (EWaSDRiP). These delays are attributed to owner, consultant, project characteristics, and external factors. Data was collected through literature review, observations on project reports, interview, and questionnaire surveys with 30 respondents from government client teams, contractors and consultants. The respondents were asked to validate the indicators, and estimate their weight and the degree of accuracy. A 1 to 10 Likert scale reflecting worst to excellent is used to score the state of each of the delay indicators within three zones, i.e. red (scale 1-3), yellow (4-6), green (7-10). The delays in red zone indicates that they pose dangerous threats to the project and must be monitored closely, delays within yellow zone indicate moderate threats to the project, while delays in green zone means that they are unlikely to delay the project. EWaSDRiP gives a visual indication of which zone most delays are distributed. This prototype is potentially beneficial for the owner or government client team to prepare strategic actions for the relevant pre-construction delays accordingly.

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Whitaker, John, Nollaig O'Donohoe, Max Denning, Dan Poenaru, Elena Guadagno, Andrew J. M. Leather, and Justine I. Davies. "Assessing trauma care systems in low-income and middle-income countries: a systematic review and evidence synthesis mapping the Three Delays framework to injury health system assessments." BMJ Global Health 6, no. 5 (May 2021): e004324. http://dx.doi.org/10.1136/bmjgh-2020-004324.

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BackgroundThe large burden of injuries falls disproportionately on low/middle-income countries (LMICs). Health system interventions improve outcomes in high-income countries. Assessing LMIC trauma systems supports their improvement. Evaluating systems using a Three Delays framework, considering barriers to seeking (Delay 1), reaching (Delay 2) and receiving care (Delay 3), has aided maternal health gains. Rapid assessments allow timely appraisal within resource and logistically constrained settings. We systematically reviewed existing literature on the assessment of LMIC trauma systems, applying the Three Delays framework and rapid assessment principles.MethodsWe conducted a systematic review and narrative synthesis of articles assessing LMIC trauma systems. We searched seven databases and grey literature for studies and reports published until October 2018. Inclusion criteria were an injury care focus and assessment of at least one defined system aspect. We mapped each study to the Three Delays framework and judged its suitability for rapid assessment.ResultsOf 14 677 articles identified, 111 studies and 8 documents were included. Sub-Saharan Africa was the most commonly included region (44.1%). Delay 3, either alone or in combination, was most commonly assessed (79.3%) followed by Delay 2 (46.8%) and Delay 1 (10.8%). Facility assessment was the most common method of assessment (36.0%). Only 2.7% of studies assessed all Three Delays. We judged 62.6% of study methodologies potentially suitable for rapid assessment.ConclusionsWhole health system injury research is needed as facility capacity assessments dominate. Future studies should consider novel or combined methods to study Delays 1 and 2, alongside care processes and outcomes.

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9

Young, G. E., K. S. Suresh Rao, and Vijay R. Chatufale. "Block-Recursive Identification of Parameters and Delay in the Presence of Noise." Journal of Dynamic Systems, Measurement, and Control 117, no. 4 (December 1, 1995): 600–607. http://dx.doi.org/10.1115/1.2801120.

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This paper presents a method for identification of parameters and delays of a linear system in the presence of noise. The estimation procedure is based on transforming the input-output data into the discrete Fourier domain. The transformed data is then solved block recursively to obtain both the system parameters and unknown delay. For systems with no delays or known delays, the equations are linear in the parameters and the standard estimation techniques can be applied. For systems with unknown delays, the resulting equations are nonlinear in the delay term. A recursive nonlinear estimation technique similar to the least-squares in the time domain has been developed. In the presence of Gaussian white noise, simulation studies indicate that the parameters converge to their true values in the mean.

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Yang, Bao Sheng, Bao Sheng Yang, and Li Li Chen. "Algorithm Design and Convergence Analysis of Iterative Adaptive Dynamic Programming." Applied Mechanics and Materials 336-338 (July 2013): 852–55. http://dx.doi.org/10.4028/www.scientific.net/amm.336-338.852.

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Time delays are tremendous difficulties to system stability analysis and controller design, and often cause system instability or even lead to the deterioration of the system performance. The optimal control law is solved for a class of nonlinear discrete affine systems with multiple time delays. The systems HJB equation of optimal control is solved by adaptive dynamic iterative algorithm and minimized system performance index function, given the convergence proof of the algorithm. Neural networks are adopted to realize iterative algorithm for optimal control law of time delay systems. The simulation results show that the adaptive dynamic programming can solve for the optimal control of delay nonlinear systems, make the system to achieve stability.

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11

Dou, Chun-xia, Zhi-sheng Duan, Xing-bei Jia, Xiao-gang Li, Jin-zhao Yang, Ting Gui, and Ye-fei Bi. "Delay-Dependent Robust Stabilization for Nonlinear Large Systems via Decentralized Fuzzy Control." Mathematical Problems in Engineering 2011 (2011): 1–20. http://dx.doi.org/10.1155/2011/605794.

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A delay-dependent robust fuzzy control approach is developed for a class of nonlinear uncertain interconnected time delay large systems in this paper. First, an equivalent T–S fuzzy model is extended in order to accurately represent nonlinear dynamics of the large system. Then, a decentralized state feedback robust controller is proposed to guarantee system stabilization with a prescribedH∞disturbance attenuation level. Furthermore, taking into account the time delays in large system, based on a less conservative delay-dependent Lyapunov function approach combining with linear matrix inequalities (LMI) technique, some sufficient conditions for the existence ofH∞robust controller are presented in terms of LMI dependent on the upper bound of time delays. The upper bound of time-delay and minimizedH∞performance index can be obtained by using convex optimization such that the system can be stabilized and for all time delays whose sizes are not larger than the bound. Finally, the effectiveness of the proposed controller is demonstrated through simulation example.

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Freitas, Angela Gabrielly Quirino, and Mathias Weller. "Patient delays and system delays in breast cancer treatment in developed and developing countries." Ciência & Saúde Coletiva 20, no. 10 (October 2015): 3177–89. http://dx.doi.org/10.1590/1413-812320152010.19692014.

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AbstractDelays in treating breast cancer have been associated with a more advanced stage of the disease and a decrease in patient survival rates. The scope of this integrative review was to analyze the main causal factors and types of patient and system delays. The underlying causal factors of delays were compared among studies conducted in developing and developed countries. Of the 53 studies selected, 24 were carried out in developing countries and 29 in developed countries, respectively. Non-attribution of symptoms to cancer, fear of the disease and treatment and low educational level were the most frequent causes of patient delay. Less comprehensive health insurance coverage, older/younger age and false negative diagnosis tests were the three most common causal factors of system delay. The effects of factors such as age were not decisive per se and depended mainly on the social and cultural context. Some factors caused both patient delay and system delay. Studies conducted in developing countries identified more causal factors of patient delay and had a stronger focus on patient delay or the combination of both. Studies conducted in developed countries had a stronger focus on aspects of system delay during treatment and guidance of breast cancer patients in the health care system.

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13

Meng, Xiang Yin, Shi De Xiao, and Hui Ping Huang. "Observable State Space Realization of Networked MIMO System for a Novel Virtual Observer-Based Delay Compensation." Advanced Materials Research 482-484 (February 2012): 1840–50. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.1840.

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With the ever increasing complexity of cyber-physical system, the coupling and interconnection between distributed nodes lead to a complicated description in mathematics. For example, time delays cannot be ignored in the cyber-physical system modeling. And delay compensation often requires the delayed Multi-Input-Multi-Output (MIMO) system to be presented in state space model and all time delays to be combined to sole side of input or output. The aim of this paper is to model the MIMO system with multiple delays in state space form and simultaneously combine both input and output delays into output channel only. In this paper, following up with the modeling of Networked MIMO System, an observable state-space realization of delayed transfer function matrix is developed, including the case with repeated poles. Meanwhile, multiple time delays are combined and allocated to the output side only. Based on the observable state space model, an observer can be designed and contributed to the delay compensation. Derivation and simulation results prove that the resulting model of Networked Control System (NCS) through the proposed modeling method is equivalent with the original networked MIMO system with both input and output delays in terms of input-output relationship, and thus it can be used in the prospective observer-based delay.

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Li, Li. "New Approach to Non-Fragile Control of Uncertain Fuzzy Systems with Time-Delay." Applied Mechanics and Materials 433-435 (October 2013): 1131–35. http://dx.doi.org/10.4028/www.scientific.net/amm.433-435.1131.

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This paper focuses on the delay-dependent stability analysis and stabilization for T-S fuzzy system systems with state and input delays. Some new and less conservative delay-dependent small stability conditions are explicitly obtained. The upper bounds of time-delays are obtained by using small convex optimization.Finally, a numerical example is included to show the effectiveness.

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Saleem, M., and Tanuja Agrawal. "Chaos in a Tumor Growth Model with Delayed Responses of the Immune System." Journal of Applied Mathematics 2012 (2012): 1–16. http://dx.doi.org/10.1155/2012/891095.

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A simple prey-predator-type model for the growth of tumor with discrete time delay in the immune system is considered. It is assumed that the resting and hunting cells make the immune system. The present model modifies the model of El-Gohary (2008) in that it allows delay effects in the growth process of the hunting cells. Qualitative and numerical analyses for the stability of equilibriums of the model are presented. Length of the time delay that preserves stability is given. It is found that small delays guarantee stability at the equilibrium level (stable focus) but the delays greater than a critical value may produce periodic solutions through Hopf bifurcation and larger delays may even lead to chaotic attractors. Implications of these results are discussed.

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16

Otto, A., W. Just, and G. Radons. "Nonlinear dynamics of delay systems: an overview." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 377, no. 2153 (July 22, 2019): 20180389. http://dx.doi.org/10.1098/rsta.2018.0389.

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Time delays play an important role in many fields such as engineering, physics or biology. Delays occur due to finite velocities of signal propagation or processing delays leading to memory effects and, in general, infinite-dimensional systems. Time delay systems can be described by delay differential equations and often include non-negligible nonlinear effects. This overview article introduces the theme issue ‘Nonlinear dynamics of delay systems’, which contains new fundamental results in this interdisciplinary field as well as recent developments in applications. Fundamentally, new results were obtained especially for systems with time-varying delay and state-dependent delay and for delay system with noise, which do often appear in real systems in engineering and nature. The applications range from climate modelling over network dynamics and laser systems with feedback to human balancing and machine tool chatter. This article is part of the theme issue ‘Nonlinear dynamics of delay systems’.

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MENG, XINZHU, and LANSUN CHEN. "PERMANENCE AND GLOBAL STABILITY IN AN IMPULSIVE LOTKA–VOLTERRA N-SPECIES COMPETITIVE SYSTEM WITH BOTH DISCRETE DELAYS AND CONTINUOUS DELAYS." International Journal of Biomathematics 01, no. 02 (June 2008): 179–96. http://dx.doi.org/10.1142/s1793524508000151.

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In this paper, we formulate a robust impulsive Lotka–Volterra n-species competitive system with both discrete delays and continuous delays. Our results in this paper indicate that under the appropriate linear bounded impulsive perturbations, the impulsive delay Lotka–Volterra system remains the original permanence and globally asymptotical stability of the nonimpulsive delay Lotka–Volterra system. We show that the conditions for the permanence and globally asymptotical stability of the system depend on time delays, so, we call it "profitless".

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Li, Yuling. "Stabilization of Teleoperation Systems with Communication Delays: An IMC Approach." Journal of Robotics 2018 (2018): 1–9. http://dx.doi.org/10.1155/2018/1018086.

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The presence of time delays in communication introduces a limitation to the stability of bilateral teleoperation systems. This paper considers internal model control (IMC) design of linear teleoperation system with time delays, and the stability of the closed-loop system is analyzed. It is shown that the stability is guaranteed delay-independently. The passivity assumption for external forces is removed for the proposed design of teleoperation systems. The behavior of the resulting teleoperation system is illustrated by simulations.

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Thangaiah, Jesintha Mary, and Rangarajan Parthasarathy. "Delay-dependent stability analysis of power system considering communication delays." International Transactions on Electrical Energy Systems 27, no. 3 (August 22, 2016): e2260. http://dx.doi.org/10.1002/etep.2260.

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Delgado, Emma, Miguel Díaz-Cacho, and Antonio Barreiro. "Stability of Teleoperation Systems for Time-Varying Delays by Neutral LMI Techniques." Mathematical Problems in Engineering 2012 (2012): 1–17. http://dx.doi.org/10.1155/2012/467629.

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This paper investigates the delay-dependent stability of a teleoperation system based on the transparent Generalized Four-Channel control (G-4C) scheme under time-varying communication delays. To address stability we choose here a primitive result providing a Linear Matrix Inequalities (LMIs) approach based on Lyapunov-Krasovskii functionals. Firstly, the scheme is modeled as the neutral-type differential-delayed equation; that is, the delay affects not only the state but also the state derivative. Secondly, we apply a less conservative stability criteria based on LMIs that are delay dependent and delay's time-derivative dependent. The reason is that, for better performance in the case of small delays, we must accept the possibility that stability is lost for large delays. The approach is applied to an example, and its advantages are discussed. As a result, we propose to modify the values of standard controllers in G-4C defining theμ-4C scheme, which introduces a tuning factorμto increase in practical conditions the stable region fixing the desired bounds on time-varying delay, with the particularity of maintaining the tracking properties provided by this transparent control scheme. The simulation results justify the proposed control architecture and confirm robust stability and performance.

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Cao, Yiran, Toshiki Oguchi, Paul Verhoeckx, and Henk Nijmeijer. "Consensus Control for a Multiagent System with Time Delays." Mathematical Problems in Engineering 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/4063184.

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In this paper, we consider the consensus control problem for a multiagent system (MAS) consisting of integrator dynamics with input and output time delays. First, we investigate a consensus condition for the MAS with a linear controller and without any delay compensation. We then propose a consensus controller with a state predictor to compensate the effect of time delay. The consensus condition for this controller is derived and investigated. Finally, we present an example of solving the consensus control problem for two-wheel mobile robots with feedback loops that pass through a computer network with time delays. To demonstrate the validity of the predictor-based controller, we conduct experiments with two-wheel mobile robots and present the results.

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Bai, Yu, Zhao Di Xu, Chao Deng, and Chang Liu. "Delay-Dependent Absolute Stability Analysis of Lurie Control System with Multiple Delays." Advanced Materials Research 631-632 (January 2013): 1195–200. http://dx.doi.org/10.4028/www.scientific.net/amr.631-632.1195.

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This paper investigates the stability problem for Lurie control system with multiple delays. The system with multiple time-delays is transformed, then the delay divided into several segments, a novel Lyapunov functional is introduced and some new delay-dependent stability criteria are derived by employed integral-equality technique. It is theoretically proved that the obtained criteria are less conservative than some existing ones. An example is given to illustrate the effectiveness of the proposed results.

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Yi, Hyun-Chul, Cheol-Jin An, and Joon-Young Choi. "Compensation of Time-Varying Delay in Networked Control System over Wi-Fi Network." International Journal of Computers Communications & Control 12, no. 3 (April 23, 2017): 415. http://dx.doi.org/10.15837/ijccc.2017.3.2617.

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In this study, we design a state predictor-based output feedback controller that compensates for unavoidable time-varying network delays in networked control systems (NCSs) over Wi-Fi networks. We model time-varying network delays as timevarying input delays of NCSs over Wi-Fi networks. The designed controller consists of a linear quadratic regulator (LQR), a full-order observer, and a time-varying stepahead state predictor. The state predictor plays a key role in compensating for the time-varying input delay by providing the LQR with an estimation of future states ahead by the current network delay time. The time-varying network delays are acquired in real time by measuring the time differences between sent and received control data packets. We verify the stability and compensation performance of the designed controller by performing extensive experiments for an NCS in which a rotary inverted pendulum is controlled over Wi-Fi networks.

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Nijhawan, Romi. "Visual prediction: Psychophysics and neurophysiology of compensation for time delays." Behavioral and Brain Sciences 31, no. 2 (April 2008): 179–98. http://dx.doi.org/10.1017/s0140525x08003804.

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AbstractA necessary consequence of the nature of neural transmission systems is that as change in the physical state of a time-varying event takes place, delays produce error between the instantaneous registered state and the external state. Another source of delay is the transmission of internal motor commands to muscles and the inertia of the musculoskeletal system. How does the central nervous system compensate for these pervasive delays? Although it has been argued that delay compensation occurs late in the motor planning stages, even the earliest visual processes, such as phototransduction, contribute significantly to delays. I argue that compensation is not an exclusive property of the motor system, but rather, is a pervasive feature of the central nervous system (CNS) organization. Although the motor planning system may contain a highly flexible compensation mechanism, accounting not just for delays but also variability in delays (e.g., those resulting from variations in luminance contrast, internal body temperature, muscle fatigue, etc.), visual mechanisms also contribute to compensation. Previous suggestions of this notion of “visual prediction” led to a lively debate producing re-examination of previous arguments, new analyses, and review of the experiments presented here. Understanding visual prediction will inform our theories of sensory processes and visual perception, and will impact our notion of visual awareness.

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Rahman, B. "Time-Delay Systems: An Overview." Nonlinear Phenomena in Complex Systems 23, no. 2 (July 9, 2020): 192–95. http://dx.doi.org/10.33581/1561-4085-2020-23-2-192-195.

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Time-delay naturally arises in many real-world systems, due to the fact that the instantaneous rate of change of such systems does not only depend on their current time but rather on their previous history as well. Hence, time-delays are ubiquitous, their introduction often leads to suppression of oscillations, multistability and chaotic motion in the dynamical systems. This review presents some models with different kinds of time-delays such as discrete, distributed and combination of both discrete and distributed time-delays with special emphasis on the reason of incorporating such delays into the system.

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Li, Chong. "Robust Reliable Control for a Class of Uncertain Discrete-Time Systems with Multiple Time-Varying Delays." Advanced Materials Research 630 (December 2012): 396–401. http://dx.doi.org/10.4028/www.scientific.net/amr.630.396.

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The robust reliable control design problem of uncertain discrete-time control systems with multiple time-varying delays is addressed in this article. Uncertainty in system is assumed to satisfy the norm-bounded condition and the time-delay parameter is time-varying unstructured. Under the proposed concepts of exponentially robust stability and exponentially robust stabilization, the delay-dependent exponential stability condition for the robust reliable control system is derived and a new delay-dependent state feedback controller design method is provided. The relationship between system stability and time-delays is also studied. Simulation study shows the effectiveness and feasibility of the proposed controller design method.

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Gerdes, Mike, Dieter Scholz, and Diego Galar. "Effects of condition-based maintenance on costs caused by unscheduled maintenance of aircraft." Journal of Quality in Maintenance Engineering 22, no. 4 (October 10, 2016): 394–417. http://dx.doi.org/10.1108/jqme-12-2015-0062.

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Purpose The purpose of this paper is to analyze the effects of condition-based maintenance based on unscheduled maintenance delays that were caused by ATA chapter 21 (air conditioning). The goal is to show the introduction of condition monitoring in aircraft systems. Design/methodology/approach The research was done using the Airbus In-Service database to analyze the delay causes, delay length and to check if they are easy to detect via condition monitoring or not. These results were then combined with delay costs. Findings Analysis shows that about 80 percent of the maintenance actions that cause departure delays can be prevented when additional sensors are introduced. With already existing sensors it is possible to avoid about 20 percent of the delay causing maintenance actions. Research limitations/implications The research is limited on the data of the Airbus in-service database and on ATA chapter 21 (air conditioning). Practical implications The research shows that delays can be prevented by using existing sensors in the air conditioning system for condition monitoring. More delays can be prevented by installing new sensors. Originality/value The research focuses on the effect of the air conditioning system of an aircraft on the delay effects and the impact of condition monitoring on delays.

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Lu, Hongying. "Permanence of a Discrete Nonlinear Prey-Competition System with Delays." Discrete Dynamics in Nature and Society 2009 (2009): 1–15. http://dx.doi.org/10.1155/2009/605254.

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A discrete nonlinear prey-competition system withm-preys and (n-m)-predators and delays is considered. Two sets of sufficient conditions on the permanence of the system are obtained. One set is delay independent, while the other set is delay dependent.

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Sun, Yuangong. "Delay-Independent Stability of Switched Linear Systems with Unbounded Time-Varying Delays." Abstract and Applied Analysis 2012 (2012): 1–11. http://dx.doi.org/10.1155/2012/560897.

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This paper is focused on delay-independent stability analysis for a class of switched linear systems with time-varying delays that can be unbounded. When the switched system is not necessarily positive, we first establish a delay-independent stability criterion under arbitrary switching signal by using a new method that is different from the methods to positive systems in the literature. We also apply this method to a class of time-varying switched linear systems with mixed delays.

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Dalwai, Ebrahim, and Ines Buccimazza. "System delays in breast cancer." South African Journal of Surgery 53, no. 2 (September 25, 2015): 40. http://dx.doi.org/10.7196/sajsnew.7741.

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de Boeij, Jeroen, Maarten Haazen, Peter Smulders, and Elena Lomonova. "Low-Latency Wireless Data Transfer for Motion Control." Journal of Control Science and Engineering 2009 (2009): 1–11. http://dx.doi.org/10.1155/2009/591506.

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This paper discusses a new approach for wireless motion control. Existing wireless techniques suffer from large closed loop delays of several milliseconds, which is unacceptable in precision motion systems. These large delays are mainly caused by the protocol used, since these are optimized for transferring large amounts of data, not to minimize transmission delay. A new protocol and wireless system are proposed that reduce the closed loop transmission delay to less than 300 microseconds. The system has been verified in a real control system, and measurements show the performance, which is more than ten times better than existing techniques.

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Kai, Lei, Huang Huai, Wen Min Wang, and Qiang Ma. "A Scheduler Designed for the P2P Live Streaming System." Advanced Materials Research 756-759 (September 2013): 1889–93. http://dx.doi.org/10.4028/www.scientific.net/amr.756-759.1889.

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P2P(peer to peer) live streaming is currently a popular research topic, but for the defective of system architecture and scheduling policy, existing P2P streaming applications have poor user experience, such as long startup delay, long playback delay, and low playback continuity. In this paper, we aim at reducing the playback delay from the source in the environment of heterogeneous upload bandwidth, heterogeneous and dynamic propagation delays. We propose a neighbor selection method in order to utilize the capacity of the peer and consider their scheduler playback deadline. This new peering strategy typically leads to low scheduling delays and improve the playback continuity. Finally we apply a receiver driven chunk selection with a mix scheduling algorithm. Through simulation, we can observe that our scheduler can outperform.

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Ottensmeyer, Mark P., Jianjuen Hu, James M. Thompson, Jie Ren, and Thomas B. Sheridan. "Investigations into Performance of Minimally Invasive Telesurgery with Feedback Time Delays." Presence: Teleoperators and Virtual Environments 9, no. 4 (August 2000): 369–82. http://dx.doi.org/10.1162/105474600566871.

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This paper describes the testbed telesurgery system that was developed in MIT's Human Machine Systems Laboratory. This system was used to investigate the effects of communication time delays on controller stability and on the performance of surgical tasks. The system includes a bilateral force-reflecting teleoperator system, interchangeable surgical tools, audio and video communication between the master and slave sites, and methods to generate time delays between the sites. To compensate for the time delays, various control schemes were investigated, leading to the development and selection of fuzzy sliding control (FSC). With a stable teleoperator system, experiments in performing a variety of surgical exercises were conducted. These looked at the performance of a team of a telesurgeon and local assistant given a number of different time-delay scenarios, including synchronous and asynchronous force and audio/video feedback. The results of the research project include the development of the novel FSC algorithm, data on how time delays degrade performance of surgical tasks, and recommendations on how telesurgery should be performed to accommodate telecommunication time delays.

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Shi, Mengji, and Kaiyu Qin. "Distributed Control for Multiagent Consensus Motions with Nonuniform Time Delays." Mathematical Problems in Engineering 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/3567682.

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This paper solves control problems of agents achieving consensus motions in presence of nonuniform time delays by obtaining the maximal tolerable delay value. Two types of consensus motions are considered: the rectilinear motion and the rotational motion. Unlike former results, this paper has remarkably reduced conservativeness of the consensus conditions provided in such form: for each system, if all the nonuniform time delays are bounded by the maximal tolerable delay value which is referred to as “delay margin,” the system will achieve consensus motion; otherwise, if all the delays exceed the delay margin, the system will be unstable. When discussing the system which is intended to achieve rotational consensus motion, an expanded system whose state variables are real numbers (those of the original system are complex numbers) is introduced, and corresponding consensus condition is given also in the form of delay margin. Numerical examples are provided to illustrate the results.

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Rebenda, Josef, and Zdeněk Šmarda. "Stability of a Functional Differential System with a Finite Number of Delays." Abstract and Applied Analysis 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/853134.

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The paper is devoted to the study of asymptotic properties of a real two-dimensional differential system with unbounded nonconstant delays. The sufficient conditions for the stability and asymptotic stability of solutions are given. Used methods are based on the transformation of the considered real system to one equation with complex-valued coefficients. Asymptotic properties are studied by means of Lyapunov-Krasovskii functional. The results generalize some previous ones, where the asymptotic properties for two-dimensional systems with one or more constant delays or one nonconstant delay were studied.

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Wiyandra, Yogi, and Firna Yenila. "Expert System Delayed Walking in the Toddler." Jurnal KomtekInfo 7, no. 2 (April 18, 2020): 152–58. http://dx.doi.org/10.35134/komtekinfo.v7i2.75.

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Delayed walking is a disorder of walking delay in the toddler aged 9-18 months. There are several indicators that cause delays in walking on children including motor, genetic and temperament. These factors are rarely understood by parents. And sometimes the delays seem to be left unchecked and that can cause its own failure. The lack of time to consult with a child specialist has resulted in such cases seeming to be left unchecked. Expert systems are built to provide knowledge to the public about the phenomena of walking delays that occur in children and the causes and solutions that will be obtained by parents. This system was built using a forward chaining method whose data reading was traced to the daily activities of toddlers. This system is designed to adapt information directly from child experts or child specialists who understand firsthand the condition of the child and delayed walking.

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Liu, Juan, and Qingdao Huang. "RobustH∞Control for Switched Nonlinear System with Multiple Delays." Mathematical Problems in Engineering 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/852303.

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This paper focuses on the problem of robustH∞control for a class of switched nonlinear systems with multiple time delays which are allowed to appear not only in state but also in input. We will design a controller and a switching law under which the system is “robust stable” and has performanceL2-gainγ. Besides, multiple Lyapunov-Razumikhin functions which are relatively less conservative are introduced to investigate the stability of the candidate switched system. In detail, firstly, for uncertain nonlinear switched system with time-varying delays, sufficient condition is given by inequalities which are equivalent to LMIs, so it is easy to be solved; then, as a special case, nonlinear switched system with constant time delay is also considered. Finally, by providing numerical examples, the feasibility of the proposed approach is demonstrated.

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Pak, H. Ali, and G. Q. Li. "Estimation of Subsample Delays for Computer Control Systems." Journal of Dynamic Systems, Measurement, and Control 114, no. 4 (December 1, 1992): 714–17. http://dx.doi.org/10.1115/1.2897745.

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A new method is described for estimating input time delays in linear plants. The method is based on discrete-time domain identification of such delays, and provides direct estimates in real-time. For computer control systems, the delay is allowed to be a noninteger multiple of the sampling period. Both input (actuator) delays and subsample (computational) delays can be estimated. The identification algorithm is based on a recursive Gaussian-Newton prediction error search technique. A simulation study indicating fast convergence for a second order delayed system is included.

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Zhang, Mingyuan, Xuting Zhou, Yu Zhang, Lijun Sun, Ming Dun, Wenbo Du, and Xianbin Cao. "Propagation Index on Airport Delays." Transportation Research Record: Journal of the Transportation Research Board 2673, no. 8 (April 28, 2019): 536–43. http://dx.doi.org/10.1177/0361198119844240.

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This paper explores the propagation effect of flight delays among airports in the aviation system and proposes a new measure, the propagation index, to effectively analyze the interrelationship among airports in relation to flight delays. This index quantifies the effect of delay propagation by measuring the causality among delay time series. To assess the effectiveness of the proposed index on airport delays, three neural network-based regression models are built. The comparative experiments demonstrate that the propagation index proposed is highly correlated with observed airport delays.

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Skardal, Per Sebastian. "Stability Diagram, Hysteresis, and Critical Time Delay and Frequency for the Kuramoto Model with Heterogeneous Interaction Delays." International Journal of Bifurcation and Chaos 28, no. 05 (May 2018): 1830014. http://dx.doi.org/10.1142/s0218127418300148.

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We investigate the dynamics of large, globally-coupled systems of Kuramoto oscillators with heterogeneous interaction delays. For the case of exponentially distributed time delays we derive the full stability diagram that describes the bifurcations in the system. Of particular interest is the onset of hysteresis where both the incoherent and partially synchronized states are stable for a range of coupling strengths — this occurs at a codimension-two point at the intersection between a Hopf bifurcation and saddle node bifurcation of cycles. By studying this codimension-two point we find the full set of characteristic time delays and natural frequencies where bistability exists and identify the critical time delay and critical natural frequency below which bistability does not exist. Finally, we examine the dynamics of the more general system where time delays are drawn from a Gamma distribution, finding that more homogeneous time delay distributions tend to both promote the onset of synchronization and inhibit the presence of hysteresis.

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Fan, Zeming, Xiaojun Yu, Hao Wan, Meilin Kang, Yuan Liu, Yuye He, and Gaoxi Xiao. "A Time-Delay-Bounded Data Scheduling Algorithm for Delay Reduction in Distributed Networked Control Systems." Mathematical Problems in Engineering 2020 (July 21, 2020): 1–12. http://dx.doi.org/10.1155/2020/8290879.

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As a key feature of networked control systems (NCSs), the time delays induced by communication medium sharing and data exchange over the system components could largely degrade the NCS performances or may even cause system instability, and thus, it is of critical importance to reduce time delays within NCSs. This paper studies the time-delay reduction problem in distributed NCSs and presents a dual-way data scheduling mechanism for time-delay reductions in delay-bounded NCSs with time-varying delays. We assess the time delays and their influences on the NCSs first with various delay factors being considered and then describe a one-way scheduling mechanism for network-delay reductions in NCSs. Based upon such a method, a dual-way scheduling algorithm is finally proposed for distributed NCSs with different types of transmitted data packets. Experiments are conducted on a remote teaching platform to verify the effectiveness of the proposed dual-way scheduling mechanism. Results demonstrate that, with the stability time-delay bound considered within the scheduling process, the proposed mechanism is effective for NCS time-delay reductions while addressing the stability, control accuracy, and settling time issues efficiently. Such a proposed mechanism could also be implemented together with some other existing control algorithms for time-delay reductions in NCSs. Our work could provide both useful theoretical guidance and application references for stable tracking control of delay-bounded NCSs.

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Wang, Yilin, Hamid Reza Karimi, and Zhengrong Xiang. "Delay-Dependent Control for Networked Control Systems with Large Delays." Mathematical Problems in Engineering 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/643174.

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We consider the problems of robust stability and control for a class of networked control systems with long-time delays. Firstly, a nonlinear discrete time model with mode-dependent time delays is proposed by converting the uncertainty of time delay into the uncertainty of parameter matrices. We consider a probabilistic case where the system is switched among different subsystems, and the probability of each subsystem being active is defined as its occurrence probability. For a switched system with a known subsystem occurrence probabilities, we give a stochastic stability criterion in terms of linear matrix inequalities (LMIs). Then, we extend the results to a more practical case where the subsystem occurrence probabilities are uncertain. Finally, a simulation example is presented to show the efficacy of the proposed method.

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Zhang, Jialu, Yong Fang, Chenlong Li, and Wenbo Zhu. "Formation Tracking via Iterative Learning Control for Multiagent Systems with Diverse Communication Time-Delays." Mathematical Problems in Engineering 2019 (January 20, 2019): 1–12. http://dx.doi.org/10.1155/2019/8164297.

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In this paper, we consider the formation tracking problem for multiagent systems with diverse communication time-delays by using iterative learning control (ILC) method based on the frequency domain analysis. A first-order ILC law for multiagent systems with diverse communication time-delays is first proposed and its convergence conditions are given by the general Nyquist stability criterion and Gershgorin’s disk theorem. Then, in order for the system to track accurately, a second-order ILC law is presented. The conditions for system tracking with zero error are established. Numerical simulations show that the proposed ILC laws for multiagent systems with diverse communication time-delays are able to achieve effectively formation tracking. And the convergence speed remains the same as the learning control algorithm without communication delay.

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Li, Xu-Guang, Silviu-Iulian Niculescu, and Arben Çela. "An iterative frequency-sweeping approach for stability analysis of linear systems with multiple delays." IMA Journal of Mathematical Control and Information 36, no. 2 (November 22, 2017): 379–98. http://dx.doi.org/10.1093/imamci/dnx050.

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AbstractIn this article, we study the stability of linear systems with multiple (incommensurate) delays, by extending a recently proposed frequency-sweeping approach. First, we consider the case where only one delay parameter is free while the others are fixed. The complete stability w.r.t. the free delay parameter can be systematically investigated by proving an appropriate invariance property. Next, we propose an iterative frequency-sweeping approach to study the stability under any given multiple delays. Moreover, we may effectively analyse the asymptotic behaviour of the critical imaginary roots (if any) w.r.t. each delay parameter, which provides a possibility for stabilizing the system through adjusting the delay parameters. The approach is simple (graphical test) and can be applied systematically to the stability analysis of linear systems including multiple delays. A deeper discussion on its implementation is also proposed. Finally, various numerical examples complete the presentation.

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Sun, Yutong, Jin Li, Xiaozhong Wei, and Yuling Jiao. "Tandem Design of Bus Priority Based on a Pre-Signal System." Sustainability 13, no. 18 (September 9, 2021): 10109. http://dx.doi.org/10.3390/su131810109.

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Giving buses priority is an important measure to improve the attractiveness of public transport and to reduce urban traffic congestion. Reducing bus service delays as much as possible will have a positive impact on urban traffic. Based on the pre-signal system, a bus at an intersection with a left-turn special phase is optimized by “tandem design”. The design model is applied to the entrance of an intersection to study the process of vehicle arrival and departure at the main signal and pre-signal, and to calculate and analyze the delay changes of buses, straight social vehicles (meaning vehicles other than those required to be open to traffic) and left-turn vehicles before and after the adoption of “tandem design”. The results show that when the vehicle capacity at the intersection is saturated, the delays to buses and the delays of left-turn vehicles will be significantly reduced once the “tandem design” is adopted at the entrance of a cross intersection with a special left-turn phase. However, it has little effect on the delay of straight-on vehicles; with this system, the total delay experienced by straight vehicles will be reduced to one cycle.

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Cao, Qian, Y. D. Song, Lei Wang, and Feng Yang. "Consensus for Multiagent Systems with Nonlinear Dynamics and Time Delays Using a Two-Hop Relay Adaptive Method." Abstract and Applied Analysis 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/792360.

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This paper investigates the consensus problem for multiagent systems with nonlinear dynamics and time delays. A distributed adaptive consensus protocol is proposed in which the time delays are explicitly included in the adaptive algorithm. It is shown that the resultant closed loop system involves doubly larger time delays, making the stability analysis nontrivial. Stability condition on maximum tolerable time delay is established and controlled by the proposed two-hop adaptive algorithm. The explicit expression of the delay margin is derived and analyzed in the frequency domain. Both the agent state errors and the estimation parameter errors converge to zero. A simulation example is illustrated to verify the theory results.

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Abdelkrim, Mohamed Naceur, Abdel Aitouche, Saloua Bel Hadj Ali, Rafika El Harabi, and Hadil Soltani. "Delay dependent stability analysis of Takagi-Sugeno fuzzy time-delays system." International Journal of Digital Signals and Smart Systems 3, no. 1/2/3 (2019): 150. http://dx.doi.org/10.1504/ijdsss.2019.10024899.

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Soltani, Hadil, Rafika El Harabi, Saloua Bel Hadj Ali, Abdel Aitouche, and Mohamed Naceur Abdelkrim. "Delay dependent stability analysis of Takagi-Sugeno fuzzy time-delays system." International Journal of Digital Signals and Smart Systems 3, no. 1/2/3 (2019): 150. http://dx.doi.org/10.1504/ijdsss.2019.103383.

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Schwartz, J. D., I. Arnedo, M. A. G. Laso, T. Lopetegi, J. Azana, and D. Plant. "An Electronic UWB Continuously Tunable Time-Delay System With Nanosecond Delays." IEEE Microwave and Wireless Components Letters 18, no. 2 (February 2008): 103–5. http://dx.doi.org/10.1109/lmwc.2007.915039.

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Chen, Wu-Hua, Xiaomei Lu, Zhi-Hong Guan, and Wei Xing Zheng. "Asymptotic Stability in a Neutral Delay Differential System with Variable Delays." SIAM Journal on Mathematical Analysis 37, no. 5 (January 2006): 1522–34. http://dx.doi.org/10.1137/s0036141004441167.

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Journal articles on the topic 'System Delays'

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