Delay Spike Research Articles

Performance evaluation of tcp spurious timeout detection methods under delay spike and packet loss emulating lte handover

Performance evaluation of tcp spurious timeout detection methods under delay spike and packet loss emulating lte handover

Rancang Bangun Sistem Pemantauan Infus dan Tekanan Darah pada Pasien Rawat Inap secara Real Time

The problems that often arise in inpatients, especially those that need special handling such as infusion fluids should be given is often the occurrence of negligence in the infusion bottle examination is good condition of fluids in infusion bottles and the number of droplets per minute that is not appropriate. In addition, the patient will also be disrupted when the nurse should take care of the patient's blood pressure periodically. To overcome these problems need to be made a system that can monitor all of it in real time.This system design process requires a hardware and software that is integrated in such a way that it can be used to monitor the infusion and blood pressure of the patient. The main hardware required is the infrared sensor and the pressure sensor where the sensor will be controlled by the microcontroller device which the results can be sent to the monitoring computer wirelessly. From the overall testing of the design that has been made, it can generally be applied but there are still shortcomings that occur in measuring instruments, especially blood pressure gauges where the average error occurred in the measurement of systolic pressure of 8.42% and the average error that Occurs in diastolic measurements of 4.90% and on data delivery there is a significant delay spike when given a barrier.

Performance of TCP on low‐bandwidth wireless links with delay spikes

AbstractWe model the goodput of a single TCP source on a wireless link experiencing sudden increases in Round Trip Time (RTT), that is delay spikes. Such spikes trigger spurious timeouts that reduce the TCP goodput. Renewal reward theory is used to derive a straightforward expression for TCP goodput that takes into account limited sending rates (limited window size), lost packets due to congestion and the delay spike properties such as the average spike duration and distribution of the spike intervals. The basic model is for independent and identically distributed (i.i.d.) spike intervals, and correlated spike intervals are modelled by using a modulating background Markov chain. Validation by ns2 simulations shows excellent agreement for lossless scenarios and good accuracy for moderate loss scenarios (for packet loss probabilities less than 5%). Numerical studies have also been performed to assess the impact of different spike interval distributions on TCP performance. Copyright © 2007 John Wiley & Sons, Ltd.

TCP performance in wireless networks with delay spike and different initial congestion window sizes

Previous research indicates that increasing the initial congestion window size in transmission control protocol (TCP) from one segment to roughly 4 KB can significantly improve its performance for file transfers that are small compared to the link bandwidth-delay product in wireless cellular networks. However, these networks are also likely to experience delay spikes exceeding the typical round-trip-time (RTT) figures, which can cause spurious timeouts that lead to unnecessary retransmissions and reduction of the TCP sender's transmission rate. Consequently, additional unnecessary retransmissions are needed for a large initial congestion window and thus the throughput of the TCP is degraded. This paper presents the research results on using large initial windows over wireless cellular networks. It has been shown that the throughput of TCP connection over a single bottleneck link with first-in-first-out (FIFO) transmission is degraded with enlarging initial window in the presence of delay spikes. Furthermore, TCP throughput performance is kept unchanged in the simple network topology when there is no burst delay. All these findings should be considered while setting up initial congestion window.

Packet audio playout delay adjustment: performance bounds and algorithms

In packet audio applications, packets are buffered at a receiving site and their playout delayed in order to com- pensate for variable network delays. In this paper, we con- sider the problem of adaptively adjusting the playout delay in order to keep this delay as small as possible, while at the same time avoiding excessive "loss" due to the arrival of packets at the receiver after their playout time has al- ready passed. The contributions of this paper are twofold. First, given a trace of packet audio receptions at a receiver, we present efficient algorithms for computing a bound on the achievable performance of any playout delay adjustment algorithm. More precisely, we compute upper and lower bounds (which are shown to be tight for the range of loss and delay values of interest) on the optimum (minimum) average playout delay for a given number of packet losses (due to late arrivals) at the receiver for that trace. Second, we present a new adaptive delay adjustment algorithm that tracks the network delay of recently received packets and efficiently maintains delay percentile information. This in- formation, together with a "delay spike" detection algorithm based on (but extending) our earlier work, is used to dy- namically adjust talkspurt playout delay. We show that this algorithm outperforms existing delay adjustment algorithms over a number of measured audio delay traces and performs close to the theoretical optimum over a range of parameter values of interest.

The Hebbian paradigm reintegrated: Local reverberations as internal representations

AbstractThe neurophysiological evidence from the Miyashita group's experiments on monkeys as well as cognitive experience common to us all suggests that local neuronal spike rate distributions might persist in the absence of their eliciting stimulus. In Hebb's cell-assembly theory, learning dynamics stabilize such self-maintaining reverberations. Quasi-quantitive modeling of the experimental data on internal representations in association-cortex modules identifies the reverberations (delay spike activity) as the internal code (representation). This leads to cognitive and neurophysiological predictions, many following directly from the language used to describe the activity in the experimental delay period, others from the details of how the model captures the properties of the internal representations.