• Journal of applied mathematics & informatics
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• v.22 no.1_2
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• pp.523-533
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• 2006

We analyze two finite buffers queueing system with priority scheduling dependent upon queue length. Customers are classified into two types ( type-l and type-2 ) according to their characteristics. Here, the customers can be considered as traffics such as voice and data in telecommunication networks. In order to support customers with characteristics of burstiness and time-correlation between interarrival, the arrival of the type-2 customer is assumed to be an Markov- modulated Poisson process(MMPP). The service order of customers in each buffer is determined by the queue length of two buffers. Methods of embedded Markov chain and supplementary variable give us information for queue length of two buffers. Finally, performance measures such as loss and mean delay are derived.

• Journal of applied mathematics & informatics
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• v.12 no.1_2
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• pp.291-297
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• 2003

This paper considers discrete-time two-class Ge $o^{X/}$G/1 queues with preemptive repeat priority. Service times of messages of each priority class are i.i.d. according to a general discrete distribution function that may differ between two classes. Completion times are derived for the preemptive repeat identical and different priority disciplines. By using the completion time, the stability condition for our system is investigated.d.

• Journal of Korea Society of Industrial Information Systems
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• v.11 no.3
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• pp.1-9
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• 2006

The handoff in IEEE 802.11 WLAN is a hard handoff. In hard handoff, a station has to stop the communication. As a result, the station is likely to miss some packets that arrival during the handoff process. To recover these lost packets, buffer-and-forward scheme is used. But, buffer-and-forward scheme is not efficient for real time service. In this paper, we propose new handoff scheme for real time service in home network based WLAN. The scheme uses priority queue which is recommended in IEEE 802.lie, and priority of priority queue is given to real time handoff calls. The simulation results show that the proposed scheme reduces traffic loss and transmission sequence error.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.2
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• pp.1-9
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• 1998

ATM was adopted as the switching and multiplexing technique for BISDN which aims at transmitting traffics with various characteristics in a unified network. To construct these ATM networks, the most important aspect is the design of the switching system with high performance and different service capabilities. In this paepr, we analyze the performance of an input and output queueing switch with preemptive priority which is considered to be most suitable for ATM networks. For the analysis of an input queue, we model each input queue as two separate virtual input queues for each priority class and we approximage them asindependent Geom/Geom/1 queues. And we model a virtual HOL queue which consists of HOL cells of all virtual input queues which have the same output address to obtain the mean service time at each virtual input queue. For the analysis of an output quque, we obtain approximately the arrival process into the output queue from the state of the virtual HOL queue. We use a Markov chain method to analyze these two models and obtain the maximum throughput of the switch and the mean queueing delay of cells. and analysis results are compared with simulation to verify that out model yields accurate results.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.2
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• pp.9-17
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• 1994

This paper proposes Double queue threshold QLT(Queue Length Threshold) algorithm and Hysteresis effect QLT algorithm. as being DPS(Dynamic Priority Scheduling) techniques. in order to advance the processing of multiple class traffics. Also, the performance of the proposed algorithms is analyzed through computer simulations,and the priority scheduling is analyzed using a retrial queue with two types of calls. Our simulation results show that the performance of the proposed Double queue length threshold QLT algorithm is superior to that of the conventinal QLT algorithm for 2 or more classes delay sensitive traffics. Also we find that Hysteresis effecT QLT algorithm is better mechanism than that of the existing QLT for real time and non-real time traffics.

• Journal of applied mathematics & informatics
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• v.30 no.5_6
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• pp.749-757
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• 2012

We consider the M/PH,G/1 queue with two classes of customers in which class-1 customers have deterministic impatience time and have preemptive priority over class-2 customers who are assumed to be infinitely patient. The service times of class-1 and class-2 customers have a phase-type distribution and a general distribution, respectively. We obtain performance measures of class-2 customers such as the queue length distribution, the waiting time distribution and the sojourn time distribution, by analyzing the busy period of class-1 customers. We also compute the moments of the queue length and the waiting and sojourn times.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.6
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• pp.614-620
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• 2006

Today the automobile has been changed from a mechanical system to an electronic control system fly the development of the electronic technology. In the automobile body, most of these electronic control devices are networked and managed fully by the CAN protocol. But, when a network system is overloaded, unexpected transmission delay for relative low priority objects occurs due to the static priority definition of the CAN protocol. To resolve this problem, this paper proposes a dynamic precedence queue mechanism that creates a queue for the low priority object and its relevant objects to be transmitted, which becomes urgent in an overloaded network system to keep the maximum allowable time delay. For the generated queue, the highest priority is assigned to transmit the queued objects within the shortest time. The mechanism is implemented in the logical link layer of CAN, which does not require any modification of the old CAN hardware. Effectiveness of the proposed mechanism is verified by the real experiments with an automobile network system.

• Bulletin of the Korean Mathematical Society
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• v.46 no.1
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• pp.107-116
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• 2009

We consider a single server multi-class queueing model with Poisson arrivals and relative priorities. For this queue, we derive a system of equations for the transform of the queue length distribution. Using this system of equations we find the moments of the queue length distribution as a solution of linear equations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1A
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• pp.81-89
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• 2000

In this paper, we analyzed the performance for CATV/LAN added priority problem. Upstrea nm channel which analyzed very deeply for CATV/LAN network have the preferential access property depending upon that positionand unidirectional property. To solve that fairness problem and priority, we propose the CSMA-CD/U/P-P protocolthat transmit as P1 probability if data packets happen. We assumed 2-Class priority(high, low). As the analyticresult and simulation, we obtained P1, value and its average delay time under priority problem assumed twoscenarios. Also, we get its variance value and queue length. Especially, the mean delay time increases nearer thanposition from H/E

• Journal of KIBIM
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• v.11 no.3
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• pp.1-11
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• 2021

BIM is one of the means of reducing the economic loss caused by design errors. These features of BIM have led to increased use of BIM. With the increasing use of BIM, several studies have been conducted to analyze the performance of BIM. As the importance of BIM staff is emphasized in the performance analysis of BIM, the human resource allocation of BIM staff can become an important research issue. However, there are few studies to measure the workforce effectiveness of BIM staff. Ham et al (2020) measured BIM workforce efficiency using FCFS queue model rules. Since design errors can have different effects on the project depending on the type, there are design errors that must be dealt with first. Therefore, in this study, a priority queue was used to solve design errors with high priority first. The performance of BIM-based design verification was analyzed by quantitatively analyzing the performance of BIM staff when the priority rule was applied to the design error processing sequence.