Upper Bound Of Delay Research Articles

Improving the serialisation of Trajectory approach for switched Ethernet network

Worst-case end-to-end delay analysis is important for real-time applications of switched Ethernet network. The Trajectory approach is one of the mature tools for worst-case delay analysis to calculate the upper bound of delay. The delay analysis based on the Trajectory approach as well as the packet serialisation of such networks is presented. An optimisation of packet serialisation is proposed in order to improve the Trajectory approach. A case study is illustrated to compare the improved Trajectory approach with the classical one, and the result shows that the improved Trajectory approach can get tighter upper bound of end-to-end delay.

Extending Real-Time Analysis for Wormhole NoCs

The delay upper-bound analysis problem is of fundamental importance to real-time applications in Network-on-Chips (NoCs). In the paper, we revisit two state-of-the-art analysis models for real-time communication in wormhole NoCs with priority-based preemptive arbitration and show that the models only support specific router architectures with large buffer sizes. We then propose an extended analysis model to estimate delay upper-bounds for all router architectures and buffer sizes by identifying and analyzing the differences between upstream and downstream indirect interferences according to the relative positions of traffic flows and taking the buffer influence into consideration. Simulated evaluations show that our model supports one more router architecture and applies to small buffer sizes compared to the previous models.

QoS Route Optimization Algorithm for the Dynamic Traffic and Network Service

Transforming the convolution to the (+,-) in legend domain is proposed in this paper. Based on the transformation, the Legend Transformation of service curve and arrive curve is given in the case of independent cross traffic, and the closed expression of stochastic delay and stochastic backlog is obtained. In the paper, we analyze influence of the dynamic of traffic and network to QoS parameter. Based on the analysis result, the QoS analysis in Legend domain is given, and the upper bound of delay and backlog in Legend domain. For the case of non-independent cross traffic, the relationship expression of different traffic is got. And simulation proves that the route optimization algorithm is correct.

A novel approach to delay-fractional-dependent stability criterion for linear systems with interval delay

This paper considers the problem of delay-fractional-dependent stability analysis of linear systems with interval time-varying state delay. By developing a delay variable decomposition approach, both the information of the variable dividing subinterval delay, and the information of the lower and upper bound of delay can be taken into full consideration. Then a new delay-fractional-dependent stability criterion is derived without involving any direct approximation in the time-derivative of the Lyapunov–Krasovskii (LK) functional via some suitable Jensen integral inequalities and convex combination technique. The merits of the proposed result lie in less conservatism, which are realized by choosing different Lyapunov matrices in the variable delay subintervals and estimating the upper bound of some cross term in LK functional more exactly. At last, two well-known numerical examples are employed to show the effectiveness and less conservatism of the proposed method.

Stability of nonlinearly-perturbed systems with time varying delay using LMIs

This paper studies delay dependent robust stability and the stabilization problem of nonlinear perturbed systems with time varying delay. A new set of sufficient conditions for the stability of open as well as close loop systems are obtained in the sense of Lyapunov-Krasovskii. To reduce the conservatism, the work exploits the idea of splitting the delay interval into multiple equal regions so that less information on the time delay can be imposed to derive the results. The derived criterion not only improves the upper bounds of the time delay but also does not require the derivative of the delay to be known at prior. Easily testable sufficient criteria are presented in terms of linear matrix inequalities. It is shown that the derived conditions are very less conservative while comparing the maximum allowable upper bound of delay with the existing results in literature.

Cross-Layer Scheduling for Cooperative Multi-Hop Cognitive Radio Networks

In this paper, a cross-layer optimal scheduling algorithm for cooperative multi-hop Cognitive Radio Networks (CRNs) is presented, where secondary users (SUs) assist primary users' (PUs') multi-hop transmissions and in return gain an immediate time-share of the channel proportional to their assistance. While providing deterministic upper-bounds for PU queue backlogs, the proposed algorithm approaches the optimal PU throughput arbitrarily close, with a tradeoff in the average delay upper-bounds of flows. The analysis is further extended to a model with a more general "long-term reward mechanism", where a time-averaged share of the channel is guaranteed for SUs. The proposed algorithm provides order-optimal delay for the primary traffic. Distributed implementation issues have also been investigated. The properties of the proposed algorithm have also been illustrated through simulation studies.

The impact of network topology on delay bound in wireless Ad Hoc networks

We consider single channel wireless networks with interference constraint among the links that can be activated simultaneously. The traffic flows are assumed to be single hop. Delay performance of the well known throughput optimal maximum weight link scheduling algorithm has been studied recently. In this paper, we study the relation between network topology and delay of maximum weight link scheduling algorithm. First, we consider 1-hop interference model. Under this interference model, an upper bound for the average delay of packets is derived analytically in terms of edge chromatic number of the network graph. Then the results have been extended to the case of general interference model. Under this model of interference, an upper bound for delay as a function of chromatic number of conflict graph is derived. Since chromatic number and edge chromatic number are network topology parameters, the results show that how the upper bound of delay is affected by network topology. Simulation results confirm our analytical relations.

Worst-case flow model of VL for worst-case delay analysis of AFDX

Worst-case delay analysis is important for avionics full duplex switched Ethernet (AFDX) standardised as ARINC 664. The flow model of virtual link (VL) in the worst-case delay analysis of AFDX is inaccurate, which depends only on the parameters of VL and ignores the impact from the network, so it makes the worst-case delay analysis of AFDX impractical. A worst-case flow model of VL, which takes the worst impact from the network into account, is proposed to mend the worst-case delay analysis of AFDX. This worst-case flow model of VL is applied in one of the main theoretical approaches for worst-case delay analysis, the network calculus approach. It assists the network calculus approach to get the real upper bound of delay for VL.

Robust stability analysis of switched uncertain systems with multiple time-varying delays and actuator failures

In this paper, the robust stability issue of switched uncertain multidelay systems resulting from actuator failures is considered. Based on the average dwell time approach, a set of suitable switching signals is designed by using the total activation time ratio between the stable subsystem and the unstable one. It is first proven that the resulting closed-loop system is robustly exponentially stable for some allowable upper bound of delays if the nominal system with zero delay is exponentially stable under these switching laws. Particularly, the maximal upper bound of delays can be obtained from the linear matrix inequalities. At last, the effectiveness of the proposed method is demonstrated by a simulation example.

Time-, wavelength-, and code-domain optical reflection monitoring for next-generation access-metro networks

Distributed optical reflectors are proposed to implement essential fault management operations such as fault detection, localization, and notification, in next generation all-optical access-metro networks in the optical layer. Fixed time-slots, wavelengths, or optical codes are assigned to selected key network locations along the path of a monitoring signal where corresponding mirrors are placed. The reflection received at a transmitting node enables online all-optical monitoring of the selected locations. After detailing the network architecture, we explore fundamental system design issues such as real-time fault localization algorithms, fault notification delay upperbounds, and delay line calculation algorithms for synchronous operation. Our simulation results showcase standard and long-reach passive optical networks, and demonstrate that our algorithms achieve fault notification at light speed using off-the-shelf components.

New exponential stability criteria for stochastic BAM neural networks with impulses

In this paper, we study the global exponential stability of time-delayed stochastic bidirectional associative memory neural networks with impulses and Markovian jumping parameters. A generalized activation function is considered, and traditional assumptions on the boundedness, monotony and differentiability of activation functions are removed. We obtain a new set of sufficient conditions in terms of linear matrix inequalities, which ensures the global exponential stability of the unique equilibrium point for stochastic BAM neural networks with impulses. The Lyapunov function method with the Itô differential rule is employed for achieving the required result. Moreover, a numerical example is provided to show that the proposed result improves the allowable upper bound of delays over some existing results in the literature.

Output Feedback Regulation of a Chain of Integrators With an Unknown Time-Varying Delay in the Input

We consider a problem of global regulation of a chain of integrators that has an unknown time-varying delay in the input. In contrast to the previous works in the literature, the upper bound of delay is not known. Moreover, there is no given information on the time-varying rate of delay, either. Using the dynamic gain approach inspired by the method in and the control structure of together, we construct an adaptive output feedback controller to solve the considered control problem. The only requirement is that the time-varying delay is bounded.

Exponential stability of switched systems with interval time-varying delay

By using the average dwell time approach, we identify a class of switching signals to guarantee exponential stability and L2 gain of the switched linear system with interval time-varying delay excluding zero. By taking both the lower bound and upper bound of delay into consideration in the chosen Lyapunov function, several new stability criteria are presented in terms of linear matrix inequalities. Compared with some results in the literature, it is theoretically established that our results are less restrictive.

Delay-Dependent $\hbox{H}_{\infty }$ Filter Design for Discrete-Time Fuzzy Systems With Time-Varying Delays

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper investigates delay-dependent <formula formulatype="inline"><tex Notation="TeX">$\hbox{H}_{\bm\infty }$</tex></formula> filter design problems for discrete-time fuzzy systems with time-varying delays. First, a novel delay-dependent piecewise Lyapunov–Krasovskii functional (DDPLKF) is proposed in which both the upper bound of delays and the delay interval are considered. Based on this DDPLKF, the delay-dependent stability criteria for discrete-time systems with constant or time-varying delays are obtained, respectively. Then, delay-dependent full-order and reduced-order <formula formulatype="inline"><tex Notation="TeX">$\hbox{H}_{\bm\infty }$</tex></formula> filter design approaches are proposed. The filter parameters can be obtained by solving a set of linear matrix inequalities (LMIs). Simulation examples are also given to illustrate the performance of the proposed approaches. It is shown that our approaches are less conservative and that the corresponding <formula formulatype="inline"><tex Notation="TeX">$\hbox{H}_{\bm\infty }$</tex></formula> filters can achieve better performance than the existing approaches. </para>

Impact of bounded delay on throughput in multi-hop networks

This paper presents a closed form solution relating to the impact of bounded delays on throughput in multi-hop networks. In contrast to contemporary literature that largely focuses on average delay to estimate the Quality of Service, our model focuses on an upper bound of delay, referred to as delay threshold in this paper. Traffic that exceeds the delay threshold is treated as lost throughput. The results obtained can be used in scaling resources in a multi-hop network for attaining specified levels of throughput under different thresholds of acceptable delays. Both single-hop and multi-hop transfers are addressed. The theoretical analysis presented in this paper is further corroborated by simulation. The findings presented in this paper will be very relevant to multi-hop network applications where received data that are older than a specified threshold period are not relevant and must be discarded.

An estimation of upperbound of delays for global asymptotic stability of delayed Hopfield neural networks

This paper provides an upperbound of delays for the global asymptotic stability of the equilibrium of Hopfield neural networks with transmission delays. Such a bound has important significance in both theory and application for the design of the globally stable networks. An example is also given to illustrate that the conditions of our result are feasible.