Under the current scenario, many applications, across various domains of real world, are utilizin... more Under the current scenario, many applications, across various domains of real world, are utilizing the Wireless LAN (WLAN) technology. With its growing usage, the requirement for QoS in WLAN has also gained significance. The most prevalent WLAN standard IEEE 802.11 does not provide QoS. In order to render service differentiation in the existing IEEE 802.11 scheme, we have presented a priority based differentiation scheme. The proposed scheme is implemented during the contention process of the existing DCF method. The contention window is divided with respect to various priority levels. The priority levels are decided on the basis of the data sensed by the station. The higher priority levels contend with a lower random back-off value and thus, are favored during transmission. Although, IEEE802.11e, the enhanced version of IEEE802.11, does provide QoS, our scheme is easier to implement on the existing legacy DCF systems. The proposed scheme modifies only the contention window and not parameters like Inter Frame Space, unlike IEEE 802.11e. We have presented the analysis of this suggested prioritization strategy on the basis of average delay, average throughput and packet received to packet sent ratio through the simulation result.
Quality Technology and Quantitative Management, 2013
Abstract This paper analyzes a discrete-time single server queueing system with balking and multi... more Abstract This paper analyzes a discrete-time single server queueing system with balking and multiple working vacations. The arriving customers balk (that is, do not join the queue) with a probability. The inter-arrival times of customers are assumed to be independent and geometrically distributed. The server works at a different rate rather than completely stopping service during vacations. The service times during a service period, service times during a vacation period and vacation times are assumed to be geometrically distributed. We obtain the closed form expressions for the steady-state probabilities at arbitrary and outside observer’s observation epochs. Computational experiences with a variety of numerical results are discussed in the form of tables and graphs. Moreover, some queueing models discussed in the literature are derived as special cases of our model.
This paper analyzes a discrete-time multi-server queue in which service capacity of each server i... more This paper analyzes a discrete-time multi-server queue in which service capacity of each server is a minimum of one and a maximum of b customers. The interarrival-and service-times are assumed to be independent and geometrically distributed. The queue is analyzed under the assumptions of early arrival system and late arrival system with delayed access. Besides, obtaining state probabilities at arbitrary and outside observer's observation epochs, some performance measures and waiting-time distribution in the queue have also been discussed. Finally, it is shown that in limiting case the results obtained in this paper tend to the continuous-time counterpart.
Discrete-time queues are extensively used in modelling the ATM environment at the cell level. In ... more Discrete-time queues are extensively used in modelling the ATM environment at the cell level. In this paper, we model a single-server queue with finite buffer space in a discrete-time environment where the services are performed in batches of maximum size 'b' with a ...
international journal of management science and engineering management, Jun 17, 2014
This paper presents a renewal input finite buffer queueing system with balking, reneging and mult... more This paper presents a renewal input finite buffer queueing system with balking, reneging and multiple working vacations. Arriving customers decide either to enter the system or to balk, and renege (leave the queue after entering) without being served, based on their desire for service, or their unwillingness for waiting. The inter-arrival times of customers are assumed to be arbitrarily distributed. Service times during a service period, vacation times and service times during vacation are assumed to be exponentially distributed. Employing the supplementary variable technique, we provide a recursive algorithm to compute the stationary system length distributions during vacations and regular busy periods. Based on the various system length distributions, various performance measures of the model and some special cases have been investigated. Numerical results illustrating the effect of the parameters on several performance characteristics are also presented.
Computers & mathematics with applications, Jul 1, 2007
This paper analyzes a discrete-time multiserver finite-buffer queueing system with batch renewal ... more This paper analyzes a discrete-time multiserver finite-buffer queueing system with batch renewal arrivals in which inter-batch time of batches and service times of customers are, respectively, arbitrarily and geometrically distributed. Each customer gets service from only one server. Using the supplementary variable and the imbedded Markov chain techniques, we obtain the state probabilities at prearrival, arbitrary and outside observer's observation epochs for partial-and total-batch rejection policies. The blocking probability of the first-, an arbitrary-and the last-customer in a batch, and other performance measures along with some numerical results have been discussed. The analysis of actual waiting-time distributions measured in slots of the first-, an arbitraryand the last-customer in an accepted batch has also been investigated. Finally, it is shown that in the limiting case the results obtained in this paper tend to the continuous-time counterpart.
Most recent research on healthcare systems has focused on integrating the Internet of Things (IoT... more Most recent research on healthcare systems has focused on integrating the Internet of Things (IoT), Blockchain technology, and cloud computing to enhance the performance of IoT devices with limited resource availability, create smart healthcare platforms, and offer patients the best possible healthcare service. Modern healthcare systems use large-scale sensor devices to address many challenges brought on by the conventional delivery of healthcare services. Most studies have lately identified data collection, massive data processing, geolocating, access management, device prioritization, and storing as primary issues in most IoT healthcare systems. Decentralization, privacy, security, scalability, trust, anonymity, and building geospatial-based intelligent healthcare systems for patient care are significant difficulties that most healthcare systems today must overcome. Blockchain technology in healthcare platforms is noteworthy and innovative since it opens platforms for data privacy, anonymity, and validity through the consensus process. In this work, we proposed a novel decentralized Blockchain-enabled geospatial service architecture for smart healthcare systems called BCGeo. The proposed framework offers an online geospatial healthcare service for residents of Bhubaneswar, a city in India, who are newcomers to the city and are less familiar with its local healthcare organizations. An analytical queueing method prioritizes serving Critical patients more than other patients. In contrast to previously proposed frameworks, the proposed framework includes immutability, scalability, geospatial mapping, patient prioritizing, and decentralized privacy protection policies for addressing the technical challenges in most of the current healthcare systems. Additionally, it explains the performance analysis of BCGeo. It includes graphs showing the various possible outcomes of arithmetic operations, performance measurement, and experimental results on the proposed architecture. INDEX TERMS Blockchain, geospatial web services, medical data, healthcare, queueing model, IoT.
In this paper, we discuss the waiting-time distribution for a finite-space, single-server queuein... more In this paper, we discuss the waiting-time distribution for a finite-space, single-server queueing system, in which customers arrive singly following a Poisson process and the server operates under (a,b)-bulk service rule. The queueing system has a finite-buffer capacity ‘N’ excluding the batch in service. The service-time distribution of batches follows a general distribution, which is independent of the arrival process. We first develop an alternative approach of obtaining the probability distribution for the queue length at a post-departure epoch of a batch and, subsequently, the probability distribution for the queue length at a random epoch using an embedded Markov chain, Markov renewal theory and the semi-Markov process. The waiting-time distribution (in the queue) of a random customer is derived using the functional relation between the probability generating function (pgf) for the queue-length distribution and the Laplace–Stieltjes transform (LST) of the queueing-time distri...
A simple and complete solution to determine the distributions of queue lengths at different obser... more A simple and complete solution to determine the distributions of queue lengths at different observation epochs for the model GI X /Geo/c/N is presented. In the past, various discrete-time queueing models, particularly the multi-server bulk-arrival queues with finite-buffer have been solved using complicated methods that lead to results in a non-explicit form. The purpose of this paper is to present a simple derivation for the model GI X /Geo/c/N that leads to a complete solution in an explicit form. The same method can also be used to solve the GI X /Geo/c/N queues with heavy-tailed inter-batch-arrival time distributions. The roots of the underlying characteristic equation form the basis for all distributions of queue lengths at different time epochs. All queue-length distributions are in the form of sums of geometric terms.
Under the current scenario, many applications, across various domains of real world, are utilizin... more Under the current scenario, many applications, across various domains of real world, are utilizing the Wireless LAN (WLAN) technology. With its growing usage, the requirement for QoS in WLAN has also gained significance. The most prevalent WLAN standard IEEE 802.11 does not provide QoS. In order to render service differentiation in the existing IEEE 802.11 scheme, we have presented a priority based differentiation scheme. The proposed scheme is implemented during the contention process of the existing DCF method. The contention window is divided with respect to various priority levels. The priority levels are decided on the basis of the data sensed by the station. The higher priority levels contend with a lower random back-off value and thus, are favored during transmission. Although, IEEE802.11e, the enhanced version of IEEE802.11, does provide QoS, our scheme is easier to implement on the existing legacy DCF systems. The proposed scheme modifies only the contention window and not parameters like Inter Frame Space, unlike IEEE 802.11e. We have presented the analysis of this suggested prioritization strategy on the basis of average delay, average throughput and packet received to packet sent ratio through the simulation result.
Quality Technology and Quantitative Management, 2013
Abstract This paper analyzes a discrete-time single server queueing system with balking and multi... more Abstract This paper analyzes a discrete-time single server queueing system with balking and multiple working vacations. The arriving customers balk (that is, do not join the queue) with a probability. The inter-arrival times of customers are assumed to be independent and geometrically distributed. The server works at a different rate rather than completely stopping service during vacations. The service times during a service period, service times during a vacation period and vacation times are assumed to be geometrically distributed. We obtain the closed form expressions for the steady-state probabilities at arbitrary and outside observer’s observation epochs. Computational experiences with a variety of numerical results are discussed in the form of tables and graphs. Moreover, some queueing models discussed in the literature are derived as special cases of our model.
This paper analyzes a discrete-time multi-server queue in which service capacity of each server i... more This paper analyzes a discrete-time multi-server queue in which service capacity of each server is a minimum of one and a maximum of b customers. The interarrival-and service-times are assumed to be independent and geometrically distributed. The queue is analyzed under the assumptions of early arrival system and late arrival system with delayed access. Besides, obtaining state probabilities at arbitrary and outside observer's observation epochs, some performance measures and waiting-time distribution in the queue have also been discussed. Finally, it is shown that in limiting case the results obtained in this paper tend to the continuous-time counterpart.
Discrete-time queues are extensively used in modelling the ATM environment at the cell level. In ... more Discrete-time queues are extensively used in modelling the ATM environment at the cell level. In this paper, we model a single-server queue with finite buffer space in a discrete-time environment where the services are performed in batches of maximum size 'b' with a ...
international journal of management science and engineering management, Jun 17, 2014
This paper presents a renewal input finite buffer queueing system with balking, reneging and mult... more This paper presents a renewal input finite buffer queueing system with balking, reneging and multiple working vacations. Arriving customers decide either to enter the system or to balk, and renege (leave the queue after entering) without being served, based on their desire for service, or their unwillingness for waiting. The inter-arrival times of customers are assumed to be arbitrarily distributed. Service times during a service period, vacation times and service times during vacation are assumed to be exponentially distributed. Employing the supplementary variable technique, we provide a recursive algorithm to compute the stationary system length distributions during vacations and regular busy periods. Based on the various system length distributions, various performance measures of the model and some special cases have been investigated. Numerical results illustrating the effect of the parameters on several performance characteristics are also presented.
Computers & mathematics with applications, Jul 1, 2007
This paper analyzes a discrete-time multiserver finite-buffer queueing system with batch renewal ... more This paper analyzes a discrete-time multiserver finite-buffer queueing system with batch renewal arrivals in which inter-batch time of batches and service times of customers are, respectively, arbitrarily and geometrically distributed. Each customer gets service from only one server. Using the supplementary variable and the imbedded Markov chain techniques, we obtain the state probabilities at prearrival, arbitrary and outside observer's observation epochs for partial-and total-batch rejection policies. The blocking probability of the first-, an arbitrary-and the last-customer in a batch, and other performance measures along with some numerical results have been discussed. The analysis of actual waiting-time distributions measured in slots of the first-, an arbitraryand the last-customer in an accepted batch has also been investigated. Finally, it is shown that in the limiting case the results obtained in this paper tend to the continuous-time counterpart.
Most recent research on healthcare systems has focused on integrating the Internet of Things (IoT... more Most recent research on healthcare systems has focused on integrating the Internet of Things (IoT), Blockchain technology, and cloud computing to enhance the performance of IoT devices with limited resource availability, create smart healthcare platforms, and offer patients the best possible healthcare service. Modern healthcare systems use large-scale sensor devices to address many challenges brought on by the conventional delivery of healthcare services. Most studies have lately identified data collection, massive data processing, geolocating, access management, device prioritization, and storing as primary issues in most IoT healthcare systems. Decentralization, privacy, security, scalability, trust, anonymity, and building geospatial-based intelligent healthcare systems for patient care are significant difficulties that most healthcare systems today must overcome. Blockchain technology in healthcare platforms is noteworthy and innovative since it opens platforms for data privacy, anonymity, and validity through the consensus process. In this work, we proposed a novel decentralized Blockchain-enabled geospatial service architecture for smart healthcare systems called BCGeo. The proposed framework offers an online geospatial healthcare service for residents of Bhubaneswar, a city in India, who are newcomers to the city and are less familiar with its local healthcare organizations. An analytical queueing method prioritizes serving Critical patients more than other patients. In contrast to previously proposed frameworks, the proposed framework includes immutability, scalability, geospatial mapping, patient prioritizing, and decentralized privacy protection policies for addressing the technical challenges in most of the current healthcare systems. Additionally, it explains the performance analysis of BCGeo. It includes graphs showing the various possible outcomes of arithmetic operations, performance measurement, and experimental results on the proposed architecture. INDEX TERMS Blockchain, geospatial web services, medical data, healthcare, queueing model, IoT.
In this paper, we discuss the waiting-time distribution for a finite-space, single-server queuein... more In this paper, we discuss the waiting-time distribution for a finite-space, single-server queueing system, in which customers arrive singly following a Poisson process and the server operates under (a,b)-bulk service rule. The queueing system has a finite-buffer capacity ‘N’ excluding the batch in service. The service-time distribution of batches follows a general distribution, which is independent of the arrival process. We first develop an alternative approach of obtaining the probability distribution for the queue length at a post-departure epoch of a batch and, subsequently, the probability distribution for the queue length at a random epoch using an embedded Markov chain, Markov renewal theory and the semi-Markov process. The waiting-time distribution (in the queue) of a random customer is derived using the functional relation between the probability generating function (pgf) for the queue-length distribution and the Laplace–Stieltjes transform (LST) of the queueing-time distri...
A simple and complete solution to determine the distributions of queue lengths at different obser... more A simple and complete solution to determine the distributions of queue lengths at different observation epochs for the model GI X /Geo/c/N is presented. In the past, various discrete-time queueing models, particularly the multi-server bulk-arrival queues with finite-buffer have been solved using complicated methods that lead to results in a non-explicit form. The purpose of this paper is to present a simple derivation for the model GI X /Geo/c/N that leads to a complete solution in an explicit form. The same method can also be used to solve the GI X /Geo/c/N queues with heavy-tailed inter-batch-arrival time distributions. The roots of the underlying characteristic equation form the basis for all distributions of queue lengths at different time epochs. All queue-length distributions are in the form of sums of geometric terms.
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Papers by Veena Goswami