Kilhwan Kim

T-preemptive priority queue and its application to the analysis of an opportunistic spectrum access in cognitive radio networks

We propose a new priority discipline called the T-preemptive priority discipline. Under this discipline, during the service of a customer, at every T time units the server periodically reviews the queue states of each class with different queue-review processing times. If the server finds any customers with higher priorities than the customer being serviced during the queue-review process, then the service of the customer being serviced is preempted and the service for customers with higher priorities is started immediately. We derive the waiting-time distributions of each class in the M/G/1 priority queue with multiple classes of customers under the proposed T-preemptive priority discipline. We also present lower and upper bounds on the offered loads and the mean waiting time of each class, which hold regardless of the arrival processes and service-time distributions of lower-class customers. To demonstrate the utility of the T-preemptive priority queueing model, we take as an example an opportunistic spectrum access in cognitive radio networks, where one primary (licensed) user and multiple (unlicensed) users with distinct priorities can share a communication channel. We analyze the queueing delays of the primary and secondary users in the proposed opportunistic spectrum access model, and present numerical results of the queueing analysis.

(N,n)-preemptive priority queues

In this paper, we propose a new priority discipline, called the (N,n)-preemptive priority discipline. Under this discipline, the preemption of the service of a low-class customer is determined by two thresholds N and n of the queue length of high-class customers. We consider M/G/1 priority queueing models with two customer classes under two different (N,n)-preemptive priority disciplines and derive the Probability Generating Functions (PGFs) of queue lengths of each class. We also show that, under the (N,n)-preemptive priority discipline, the QoS for high-class customers can be controlled within a certain bound, regardless of the restarting mode of a preempted service.

Service Deployment and Priority Optimization for Multiple Service-Oriented Applications in the Cloud

Submitted:January 24, 2014 1 Revision:September 8, 2014 Accepted:September 12, 2014 * 본 연구는 미래창조과학부 및 정보통신기술진흥센터의 정보통신.방송 연구개발 사업의 일환으로 수행하였음 (09-911-05-001, 네트워크 기반 수요자 지향 융합서비스 공통플랫폼 기술개발). ** 상명대학교 경영공학과 *** 한국전자통신연구원 통신인터넷연구소 This paper considers service deployment and priority optimization for multiple service-oriented applications sharing reusable services, which are deployed as multiple instances in the cloud. In order to handle variations in the workloads of the multiple applications, service instances of the individual reusable services are dynamically provisioned in the cloud. Also service priorities for each application in a particular reusable service are dynamically adjusted. In this paper, we propose an analytic performance model, based on a queueing network model, to predict the expected sojourn times of multiple service-oriented applications, given the number of service instances and priority disciplines in individual reusable services. We also propose a simple heuristic algorithm to search an optimal number of service instances in the cloud and service priority disciplines for each application in individual reusable services. A numerical example is also presented to demonstrate the applicability of the proposed performance model and algorithm to the proposed optimal decision problem. Keyword:Performance Analysis, Service-Oriented Application, Cloud Computing, Service Priority Discipline, Queueing Network 韓國IT서비스學會誌 第13卷 第3號 2014年 9月, pp.201-219 202 Kilhwan Kim.Changsup Keum.Hyun Joo Bae

preemptive priority queues

In this paper, we propose a new priority discipline, called the (N,n)-preemptive priority discipline. Under this discipline, the preemption of the service of a low-class customer is determined by two thresholds N and n of the queue length of high-class customers. We consider M/G/1 priority queueing models with two customer classes under two different (N,n)-preemptive priority disciplines and derive the Probability Generating Functions (PGFs) of queue lengths of each class. We also show that, under the (N,n)-preemptive priority discipline, the QoS for high-class customers can be controlled within a certain bound, regardless of the restarting mode of a preempted service.

(N,n)(N,n)-preemptive priority queues

In this paper, we propose a new priority discipline, called the (N,n)-preemptive priority discipline. Under this discipline, the preemption of the service of a low-class customer is determined by two thresholds N and n of the queue length of high-class customers. We consider M/G/1 priority queueing models with two customer classes under two different (N,n)-preemptive priority disciplines and derive the Probability Generating Functions (PGFs) of queue lengths of each class. We also show that, under the (N,n)-preemptive priority discipline, the QoS for high-class customers can be controlled within a certain bound, regardless of the restarting mode of a preempted service.