The effect of delayed feedback on oscillatory behaviour is investigated in the classical van der Pol’s oscillator. It is shown how the presence of delay can change the amplitude of limit cycle oscillations, or suppress them altogether. The result is compared to the conventional proportional-andderivative feedback. The derivative-like effect of delay is also demonstrated in a modified equation w...

Our aim was to determine the effect of delay to surgery on the time to discharge, in-hospital death, the presence of major and minor medical complications and the incidence of pressure sores in patients with a fracture of the hip. All patients admitted to Vancouver General Hospital with this injury between 1998 and 2001 inclusive were identified from our trauma registry. A review of the case no...

We examine a design method for robust stabilizing modified proportional– integral–derivative (PID) controllers for time-delay plants with uncertainty. The PID controller structure is very widely used in industrial applications. However, the plants to which the PID controller is applicable are restricted. Yamada, Hagiwara and Shimizu proposed a design method for robust stabilizing modified PID c...

Abstract: We consider the tradeoffs in computation complexity and network delay for a multiuser wireless network with dynamic routing and power allocation. Data arrives to each node of the network randomly, and power allocation and routing decisions are made under the assumption that the computational processing speed at each node is constrained to C floating point operations per second. We dev...

IEEE 802.16 is a standardisation for a broadband wireless access in metropolitan area networks (MAN). Since the IEEE 802.16 standard defines the concrete quality of service (QoS) requirement, a scheduling scheme is necessary to achieve the QoS requirement. Many scheduling schemes are proposed with the purpose of throughput optimisation and fairness enhancement, however, few scheduling schemes s...

The measured distribution of the single-channel delay time of localized microwave radiation and its correlation with intensity differ sharply from the behavior of diffusive waves. The delay time is found to increase with intensity, while its variance is inversely proportional to the fourth root of the intensity. The distribution of the delay time weighted by the intensity is found to be a doubl...

This paper reports the measurement and analysis of wideband radio channel at 1900 MHz within a special propagation environment as the Olympic Stadium of Athens. RMS delay spread values are evaluated as well as the coherence bandwidth of the channel is derived by the frequency correlation function. Mean delay spread was found 0.314 μs and 0.731 μs for LoS and NLoS conditions respectively. The me...

The equalizer tap length requirement is investigated analytically and numerically for differential modal group delay (DMGD) compensated fiber link with weakly random mode coupling. Each span of the DMGD compensated link comprises multiple pairs of fibers which have opposite signs of DMGD. The result reveals that under weak random mode coupling, the required tap length of the equalizer is propor...

QoS support is necessary for the Internet new applications to meet end-to-end requirements such as bandwidth, delay, jitter and packet loss. Unfortunately, DiffServ architecture can only provide limited service assurance. Thus, a trade-off between simplicity of the implementation and strength of the service guarantees has to be made. In this paper, we have focused on DiffServ architecture to im...

We discuss a new packet service paradigm, called “Less Impact Better Service” (LIBS). In simple terms, LIBS primarily schedules packets based on the delay they cause and cancels service differentiation policies when the cumulative delay due to prioritization becomes significant for non-prioritized packets. Based on LIBS, we evaluate different service policies that prioritize small packets using...