Variability Functions for Parametric-Decomposition Approximations of Queueing Networks

Analysis and control of correlated web server queues

The heavy-traffic bottleneck phenomenon in open queueing networks

Mobile operators move quickly from 2G GSM networks in urban areas to remote rural areas, which are 2G networks by offering voice connectivity. As a result, more and more technology is optimizing cellular operators that reduce and perform bandwidth efficiency that will be implemented. The optimization solution for this cellular operator produces voice communication on GSM, in a cost-effective application for satellites. This paper discusses and applies to creating GSM links via satellite communication. The ABIS interface on GSM, which is defined between the Base Transceiver Station (BTS) of GSM remote cells and the Base Station Controller (BSC), is considered here to be transferred via GSM communication with the Modulation and Coding scheme 16 APSK 5/6. The MODCOD scheme determines the efficiency of what MHz is needed to send one Mbps. The efficiency value achieved by allocating, bandwidth (MHz) generated by 1.0 Mhz is an efficiency of 3.222 [bit / baud]. And Info Data Rate is generated from the value (Mbps) of 3,175. The highest traffic intensity with the value of Traffic Volume (Hours) = 3.5, Traffic Intensity (Erlang) 0.145833333. While the lowest traffic intensity with the value of Traffic Volume (Hour) = 2.6, traffic intensity = 0.108333333 (Erlang). The value obtained on Traffic Volume and Traffic Intensity is 0.1%. Service levels are very good at grade of service, because of the small possibility of access fail. Calculation of the availability of link network availability links, using ACM 16APSK LDPC 5/6 techniques that can increase up to 100%.

In this paper, a single-server queue with negative customers is considered. The arrival of a negative customer will remove one positive customer that is being served, if any is present. An alternative approach will be introduced to derive a set of equations which will be solved to obtain the stationary queue length distribution. We assume that the service time distribution tends to a constant asymptotic rate when time t goes to infinity. This assumption will allow for finding the stationary queue length of queueing systems with non-exponential service time distributions. Numerical examples for gamma distributed service time with fractional value of shape parameter will be presented in which the steady-state distribution of queue length with such service time distributions may not be easily computed by most of the existing analytical methods.

In this paper we study a nonparametric estimation problem for stochastic feedforward systems with nodes of type G/G/$\infty.$ We assume that we have observations of the external arrival and external departure processes of customers of the system, but no information about the movements of the indistinguishable customers in the network. Our aim is the construction of estimators for the characteristic functions and the densities of the service time distributions at the nodes as well as for the routing probabilities. Since the system is only partly observed we have to clarify first if the parameters are identifiable from the given data. The crucial point in our approach is the observation that in our stochastic networks under study the influence of the arrival processes on the departure processes can be described in a linear and time-invariant model. This makes it possible to apply cross-spectral techniques for multivariate point processes. The construction of the estimators is then based on smoothed periodograms. We prove asymptotic normality for the estimators. We present the statistical analysis for a tandem system of two nodes in full details and show afterwards how the results can be generalized to feedforward systems of three or more nodes and to systems with positive feedback probabilities at the nodes.

Street characteristics and traffic factors determining road users' exposure to black carbon

We develop an approximation for a queue having an arrival process that is the superposition of independent renewal processes, i.e., ∑GI1/G/1. This model is useful, for example, in analyzing networks of queues where the arrival process to an individual queue is the superposition of departure processes from other queues. If component arrival processes are approximated by renewal processes, the ∑GI1/G/1 model applies. The approximation proposed is a hybrid that combines two basic methods described by Whitt. All these methods approximate the complex superposition process by a renewal process and yield a GI/G/1 queue that can be solved analytically or approximately. In the hybrid method, the moments of the intervals in the approximating renewal process are a convex combination of the moments determined by the basic methods. The weight in the convex combination is identified using the asymptotic properties of the basic methods together with simulation. When compared to simulation estimates, the error in hybrid approximations of the expected number in the queue is 3%; in contrast, the errors of the basic methods are 20–30%. The quality of the approximations suggests that the hybrid approach would be useful in approximating point processes in other contexts.

short-paper Share on Tail asymptotics of the stationary distribution for a two-node generalized Jackson network Author: Masakiyo Miyazawa Tokyo University of Science, Noda, Chiba, Japan Tokyo University of Science, Noda, Chiba, JapanView Profile Authors Info & Claims ACM SIGMETRICS Performance Evaluation ReviewVolume 42Issue 2September 2014pp 70–72https://doi.org/10.1145/2667522.2667545Published:04 September 2014Publication History 1citation26DownloadsMetricsTotal Citations1Total Downloads26Last 12 Months0Last 6 weeks0 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteGet Access

A significant amount of recent research has been focused on the stability of multiclass open networks of queues (MONQs). It has been shown that these networks may be unstable under various queueing disciplines even when at each one of the nodes the arrival rate is less than the service rate. Clearly, in such cases the expected delay and the expected number of customers in the system are infinite. In this paper we propose a new class of scheduling rules that can be used in multiclass queueing networks. We refer to this class as the stable shortfall-based priority (SSBP) rules. This SSBP class itself belongs to a larger class of rules, which we refer to as the shortfall-based priority (SBP) rules. SBP is a generalization of the standard non-preemptive priority rule in which customers of the same priority class are served first-come, first-served (FCFS). Rules from SBP can mimic FCFS as well as the so-called strict or head-of-the-line priority disciplines. We show that the use of any rule from the SSBP class ensures stability in a broad class of MONQs found in practice. We proceed with the construction of a sample path inequality for the work done by an SSBP server and show how this inequality can be used to derive upper bounds for the delay when service times are bounded. Bounds for the expected delay of each class of customers in an MONQ are then obtained under the assumptions that the external arrival processes have i.i.d. interarrival times, the routings are deterministic and the service times at each step of the route are bounded. In order to derive these bounds for the average delay in an MONQ we make use of some of the classical ideas of Kingman.

In this paper, the performance of peer-to-peer (P2P) file sharing service based-on flooding search algorithm is analyzed. We focus on six types of four-terminal four-router physical network, and investigate the impact of topology inconsistency and flooding search on the file retrieval performance. The analysis model is based on a two-layer queueing network in which both logical and physical topologies are taken into account, and the file search time and file transfer delay are analyzed. We observe from numerical examples that an overlay network with high node degree provides a small file search time for a low traffic intensity, while the performance of the high node-degree overlay network rapidly degrades with a high traffic intensity.

Traffic alternatives for harvesting soybean ( Glycine max L.): Effect on yields and soil under a direct sowing system

The research work was conducted to determine the concentration of Arsenic, Cupper, Strontum, and Zinc in some plant leaves (Dodoneae, Eucalyptus, Albizia Lebbeck) grown in different location in Kalar- Sulaymaneyah, Iraq to investigat contamination caused by traffic related pollutant. The samples were collected in (City Center, Industrial Area, Salih Agha village, and Garmian university campus). Concnetration of the selected elemnts were measured by inducively coupled plasma optical emission spectroscopy (ICP-OES) after wet digestion with acid mixture of (HNO3:H2O2). The mean concentration ranges of heavy metals in different plant leaves samples were: As = ND – 0.9; Cu =0.4 – 1.9; Sr =15 – 797.7 Zn = ND - 20 mg/Kg. The highest concentrations of different heavy metals were found in the samples collected from heavy traffic. The study revealed that the concnetration ranges of Sr and Zn in samples collected in higher traffic intensities were several times higher than those collected from lower traffic intensities compared to Cu and As which the increase in thier concnetration is slight.

The influence of heavy goods vehicle traffic on accidents on different types of Spanish interurban roads

Environmental pollution caused by heavy metals is an increasingly pressing ecological issue. One of the main sources of these pollutants is road transport. This study aimed to assess the impact of traffic intensity on heavy metal emissions using locally occurring vegetation as a natural indicator of environmental contamination. The research focused on a common and widely distributed plant species – dandelion (Taraxacum officinale) – analyzing its capacity to accumulate pollutants. Plant samples were collected from four different locations with varying levels of traffic: near a highway, urban roads, and a forest area used as a reference site. The plants differed visually depending on the collection site, indicating the influence of pollution on their physical condition. Laboratory analyses revealed that plants from the area with the highest traffic intensity contained approximately four times higher concentrations of selected heavy metals – including Cd, Fe, Mn, Pb and Zn – compared to samples from the forest site. These results demonstrated the ability of dandelions to accumulate heavy metals in their biomass show that local vegetation can serve as a simple, cost-effective, and non-invasive tool for environmental monitoring, supporting the planning of pollution mitigation efforts and soil phytoremediation strategies in urbanized and traffic-exposed areas.

We propose an alternative approach for studying queues based on robust optimization. We model the uncertainty in the arrivals and services via polyhedral uncertainty sets, which are inspired from the limit laws of probability. Using the generalized central limit theorem, this framework allows us to model heavy-tailed behavior characterized by bursts of rapidly occurring arrivals and long service times. We take a worst-case approach and obtain closed-form upper bounds on the system time in a multi-server queue. These expressions provide qualitative insights that mirror the conclusions obtained in the probabilistic setting for light-tailed arrivals and services and generalize them to the case of heavy-tailed behavior. We also develop a calculus for analyzing a network of queues based on the following key principles: (a) the departure from a queue, (b) the superposition, and (c) the thinning of arrival processes have the same uncertainty set representation as the original arrival processes. The proposed approach (a) yields results with error percentages in single digits relative to simulation, and (b) is to a large extent insensitive to the number of servers per queue, network size, degree of feedback, and traffic intensity; it is somewhat sensitive to the degree of diversity of external arrival distributions in the network.