Optimizing Channel Utilization for Wireless Broadcast Databases

2019 ◽  
pp. 178-203
Author(s):  
Agustinus Borgy Waluyo
Keyword(s):  
Data Dissemination ◽  
Arrival Rate ◽  
Wireless Channel ◽  
Data Item ◽  
Analytical Models ◽  
Access Time ◽  
Broadcast Channel ◽  
Service Rate ◽  
Mobile Clients ◽  
Item Size

A very large number of broadcast items affect the access time of mobile clients to retrieve data item of interest. This is due to high waiting time for mobile clients to find the desired data item over wireless channel. In this chapter, the authors propose a method to optimize query access time and hence minimize power consumption. The proposed method is divided into two stages: (1) The authors present analytical models and utilize the analytical models for both query access time over broadcast channel and on-demand channel; (2) they present a global index, an indexing scheme designed to assist data dissemination over multi broadcast channel. Several factors are taken into account, which include request arrival rate, service rate, number of request, size of data item, size of request, number of data item to retrieve, and bandwidth. Simulation models are developed to find out the performance of the analytical model. Finally, the authors compare the performance of the proposed method against the conventional approach.

Broadcast Data Placement over Multiple Wireless Channels

2011 ◽  
pp. 155-176
Author(s):  
Dimitrios Katsaros ◽  
Yannis Manolopoulos
Keyword(s):  
Wireless Channels ◽  
Effective Means ◽  
Communication Technologies ◽  
Wireless Channel ◽  
Optimal Placement ◽  
Access Time ◽  
Portable Devices ◽  
High Bandwidth ◽  
Mobile Clients

The advances in computer and communication technologies made possible an ubiquitous computing environment were clients equipped with portable devices can send and receive data anytime and from anyplace. Due to the asymmetry in communication and the scarceness of wireless resources, data broadcast is widely employed as an effective means in delivering data to the mobile clients. For reasons like heterogeneous communication capabilities and variable quality of service offerings, we may need to divide a single wireless channel into multiple physical or logical channels. Thus, we need efficient algorithms for placing the broadcast data into these multiple channels so as to reduce the client access time. The present chapter discusses algorithms for placing broadcast data to multiple wireless channels, which cannot be coalesced into a lesser number of high-bandwidth channels, assuming that there are no dependencies among the transmitted data. We give an algorithm for obtaining the optimal placement to the channels and explain its limitation since it is computationally very demanding and thus unfeasible. Then, we present heuristic schemes for obtaining suboptimal solutions to the problem of reporting on their implementation cost and their relative performance.

EFFICIENT BROADCAST INDEXING SCHEME FOR LOCATION-DEPENDENT QUERIES IN MULTI CHANNELS WIRELESS ENVIRONMENT

2005 ◽  
Vol 06 (03) ◽  
pp. 303-321 ◽  
Author(s):  
AGUSTINUS BORGY WALUYO ◽  
BALA SRINIVASAN ◽  
DAVID TANIAR
Keyword(s):  
Data Dissemination ◽  
Index Structure ◽  
Access Time ◽  
Global Index ◽  
Mobile Environment ◽  
Indexing Scheme ◽  
Wireless Broadcast ◽  
Current Location ◽  
Wireless Environment ◽  
Mobile Clients

Data dissemination scheme has been of great interest due to its scalability. In mobile environment, the advantage of such scheme is significant considering the inherent limitations of wireless environment. The application of broadcast indexing scheme in a wireless broadcast environment is necessary to help mobile clients to find the desired data instances efficiently. In this paper, we present a novel index structure called global indexing scheme for location-dependent queries. The proposed scheme is applied in a multi channel wireless environment and designed to serve queries efficiently in which the queries result depend on the mobile clients' current location. We develop a simulation model to find out the access time, tuning time and power consumption performance of global indexing scheme as compared to non-global indexing scheme. Additionally, we analyse the efficiency of valid scope used in the global index scheme as compared with an existing valid scope. It is found that global index performs substantially better than the existing indexing concept.

scholarly journals Pathwise optimality of the exponential scheduling rule for wireless channels

2004 ◽  
Vol 36 (04) ◽  
pp. 1021-1045 ◽  
Author(s):  
Sanjay Shakkottai ◽  
R. Srikant ◽  
Alexander L. Stolyar
Keyword(s):  
Queue Length ◽  
Wireless Channels ◽  
Unique Feature ◽  
Heavy Traffic ◽  
Wireless Channel ◽  
Service Rate ◽  
Resource Pooling ◽  
Scheduling Policy ◽  
Multiple Data ◽  
Heavy Traffic Limit

We consider the problem of scheduling the transmissions of multiple data users (flows) sharing the same wireless channel (server). The unique feature of this problem is the fact that the capacity (service rate) of the channel varies randomly with time and asynchronously for different users. We study a scheduling policy called the exponential scheduling rule, which was introduced in an earlier paper. Given a system withNusers, and any set of positive numbers {an},n= 1, 2,…,N, we show that in a heavy-traffic limit, under a nonrestrictive ‘complete resource pooling’ condition, this algorithm has the property that, for each timet, it (asymptotically) minimizes maxnanq̃n(t), whereq̃n(t) is the queue length of usernin the heavy-traffic regime.

scholarly journals Performance Modelling of Health-care Service Delivery in Adekunle Ajasin University, Akungba-Akoko, Nigeria Using Queuing Theory

2020 ◽  
pp. 119-127
Author(s):  
Orimoloye Segun Michael
Keyword(s):  
Health Care ◽  
Service Delivery ◽  
Queuing Theory ◽  
Health Care Service ◽  
Health Centre ◽  
Arrival Rate ◽  
Queuing System ◽  
Service Rate ◽  
Suitable Model ◽  
The Mean

The queuing theory is the mathematical approach to the analysis of waiting lines in any setting where arrivals rate of the subject is faster than the system can handle. It is applicable to the health care setting where the systems have excess capacity to accommodate random variation. Therefore, the purpose of this study was to determine the waiting, arrival and service times of patients at AAUA Health- setting and to model a suitable queuing system by using simulation technique to validate the model. This study was conducted at AAUA Health- Centre Akungba Akoko. It employed analytical and simulation methods to develop a suitable model. The collection of waiting time for this study was based on the arrival rate and service rate of patients at the Outpatient Centre. The data was calculated and analyzed using Microsoft Excel. Based on the analyzed data, the queuing system of the patient current situation was modelled and simulated using the PYTHON software. The result obtained from the simulation model showed that the mean arrival rate of patients on Friday week1 was lesser than the mean service rate of patients (i.e. 5.33> 5.625 (λ > µ). What this means is that the waiting line would be formed which would increase indefinitely; the service facility would always be busy. The analysis of the entire system of the AAUA health centre showed that queue length increases when the system is very busy. This work therefore evaluated and predicted the system performance of AAUA Health-Centre in terms of service delivery and propose solutions on needed resources to improve the quality of service offered to the patients visiting this health centre.

scholarly journals Large Deviations for the Single-Server Queue and the Reneging Paradox

2021 ◽  
Author(s):  
Rami Atar ◽  
Amarjit Budhiraja ◽  
Paul Dupuis ◽  
Ruoyu Wu
Keyword(s):  
Large Deviations ◽  
Decay Rate ◽  
Sample Path ◽  
Arrival Rate ◽  
Rate Function ◽  
Service Rate ◽  
Single Server ◽  
Large Deviations Principle ◽  
Long Run ◽  
The Individual

For the M/M/1+M model at the law-of-large-numbers scale, the long-run reneging count per unit time does not depend on the individual (i.e., per customer) reneging rate. This paradoxical statement has a simple proof. Less obvious is a large deviations analogue of this fact, stated as follows: the decay rate of the probability that the long-run reneging count per unit time is atypically large or atypically small does not depend on the individual reneging rate. In this paper, the sample path large deviations principle for the model is proved and the rate function is computed. Next, large time asymptotics for the reneging rate are studied for the case when the arrival rate exceeds the service rate. The key ingredient is a calculus of variations analysis of the variational problem associated with atypical reneging. A characterization of the aforementioned decay rate, given explicitly in terms of the arrival and service rate parameters of the model, is provided yielding a precise mathematical description of this paradoxical behavior.

Data Dissemination in Mobile Databases

2011 ◽  
pp. 914-920
Author(s):  
Agustinus Borgy Waluyo ◽  
Bala Srinivasan ◽  
David Taniar
Keyword(s):  
Response Time ◽  
Mobile Computing ◽  
Data Dissemination ◽  
Wireless Channel ◽  
Data Broadcasting ◽  
Wireless Technology ◽  
Mobile Databases ◽  
Tuning Time ◽  
Query Performance ◽  
Download Time

The development of wireless technology has led to mobile computing, a new era in data communication and processing (Barbara, 1999; Myers & Beigl, 2003). With this technology, people can now access information anytime and anywhere using a portable, wireless computer powered by battery (e.g., PDAs). These portable computers communicate with a central stationary server via a wireless channel. Mobile computing provides database applications with useful aspects of wireless technology known as mobile databases. The main properties of mobile computing include mobility, severe power and storage restriction, frequency of disconnection that is much greater than a traditional network, bandwidth capacity, and asymmetric communications costs. Radio wireless transmission usually requires a greater amount of power as compared with the reception operation (Xu, Zheng, Zhu, & Lee, 2002). Moreover, the life expectancy of a battery (e.g., nickel-cadmium, lithium ion) was estimated to increase time of effective use by only another 15% (Paulson, 2003). Thus, efficient use of energy is definitely one of the main issues. Data dissemination (can also be called data broadcasting) is one way to overcome these limitations. With this mechanism, a mobile client is able to retrieve information without wasting power to transmit a request to the server. Other characteristics of data dissemination include: scalability as it supports a large number of queries; query performance which is not affected by the number of users in a cell as well as the request rate; and effective to a high-degree of overlap in the user’s request. In this article, the terms data dissemination and data broadcasting are used interchangeably. The ultimate challenge in data dissemination is to minimize the response time and tuning time of retrieving database items. Response time is the total of elapsed time required for the data of interest to arrive in the channel and the download time, while tuning time is the amount of time that a client is required to listen to the channel, which is used to indicate its energy consumption. In some cases, the response time is equal to the tuning time. This article describes a state-of-the art development in data dissemination strategies in mobile databases. Several strategies for improving the query performance by disseminating data to a population of mobile users will be explained.

A Spatio-Temporal Cache Replacement Policy for Location Dependent Data in Mobile Environments

2010 ◽  
Vol 6 (3) ◽  
pp. 31-48 ◽  
Author(s):  
Mary Magdalene Jane.F ◽  
R. Nadarajan ◽  
Maytham Safar
Keyword(s):  
Data Access ◽  
Data Availability ◽  
Replacement Policy ◽  
Dependent Data ◽  
Access Time ◽  
Cache Replacement ◽  
Cache Replacement Policy ◽  
Active Sets ◽  
Mobile Clients ◽  
Spatio Temporal

Data caching in mobile clients is an important technique to enhance data availability and improve data access time. Due to cache size limitations, cache replacement policies are used to find a suitable subset of items for eviction from the cache. In this paper, the authors study the issues of cache replacement for location-dependent data under a geometric location model and propose a new cache replacement policy RAAR (Re-entry probability, Area of valid scope, Age, Rate of Access) by taking into account the spatial and temporal parameters. Mobile queries experience a popularity drift where the item loses its popularity after the user exhausts the corresponding service, thus calling for a scenario in which once popular documents quickly become cold (small active sets). The experimental evaluations using synthetic datasets for regular and small active sets show that this replacement policy is effective in improving the system performance in terms of the cache hit ratio of mobile clients.

scholarly journals Simple and Yet Efficient Estimators for Markovian Multiserver Queues

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Emilio Suyama ◽  
Roberto C. Quinino ◽  
Frederico R. B. Cruz
Keyword(s):  
Maximum Likelihood ◽  
Arrival Rate ◽  
Research Area ◽  
Service Rate ◽  
Traffic Intensity ◽  
Moment Estimator ◽  
Likelihood Estimator ◽  
Future Developments ◽  
Multiserver Queues

Estimators for the parameters of the Markovian multiserver queues are presented, from samples that are the number of clients in the system at arbitrary points and their sojourn times. As estimation in queues is a recognizably difficult inferential problem, this study focuses on the estimators for the arrival rate, the service rate, and the ratio of these two rates, which is known as the traffic intensity. Simulations are performed to verify the quality of the estimations for sample sizes up to 400. This research also relates notable new insights, for example, that the maximum likelihood estimator for the traffic intensity is equivalent to its moment estimator. Some limitations of the results are presented along with a detailed numerical example and topics for future developments in this research area.

Minimum carbon dioxide emission based selection of traffic route with unsignalised junctions in tandem network

2019 ◽  
Vol 30 (3) ◽  
pp. 657-675 ◽  
Author(s):  
Anand Jaiswal ◽  
Cherian Samuel ◽  
Chirag Chandan Mishra
Keyword(s):  
Carbon Dioxide ◽  
Queuing Theory ◽  
Mathematical Formulation ◽  
Carbon Dioxide Emission ◽  
Arrival Rate ◽  
Selection Strategy ◽  
Service Rate ◽  
Content Type ◽  
Fuel Consumption Rate ◽  
Route Choices

Purpose The purpose of this paper is to provide a traffic route selection strategy based on minimum carbon dioxide (CO2) emission by vehicles over different route choices. Design/methodology/approach The study used queuing theory for Markovian M/M/1 model over the road junctions to assess total time spent over each of the junctions for a route with junctions in tandem. With parameters of distance, mean service rate at the junction, the number of junctions and fuel consumption rate, which is a function of variable average speed, the CO2 emission is estimated over each of the junction in tandem and collectively over each of the routes. Findings The outcome of the study is a mathematical formulation, using queuing theory to estimate CO2 emissions over different route choices. Research finding estimated total time spent and subsequent CO2 emission for mean arrival rates of vehicles at junctions in tandem. The model is validated with a pilot study, and the result shows the best vehicular route choice with minimum CO2 emissions. Research limitations/implications Proposed study is limited to M/M/1 model at each of the junction, with no defection of vehicles. The study is also limited to a constant mean arrival rate at each of the junction. Practical implications The work can be used to define strategies to route vehicles on different route choices to reduce minimum vehicular CO2 emissions. Originality/value Proposed work gives a solution for minimising carbon emission over routes with unsignalised junctions in the tandem network.

Data Dissemination in Mobile Databases

2005 ◽  
pp. 691-697
Author(s):  
Agustinus Borgy Waluyo ◽  
Bala Srinivasan ◽  
David Taniar
Keyword(s):  
Mobile Computing ◽  
Data Dissemination ◽  
Data Communication ◽  
Wireless Channel ◽  
Wireless Technology ◽  
Database Applications ◽  
Mobile Databases ◽  
New Era ◽  
Access Information ◽  
Portable Computers

The development of wireless technology has led to mobile computing, a new era in data communication and processing (Barbara, 1999; Myers & Beigl, 2003). With this technology, people can now access information anytime and anywhere using a portable, wireless computer powered by battery (e.g., PDAs). These portable computers communicate with a central stationary server via a wireless channel. Mobile computing provides database applications with useful aspects of wireless technology known as mobile databases.

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