• The Journal of Natural Sciences
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• v.7
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• pp.75-82
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• 1995

We obtain the departure process of a D-BMAP/Geo/1/K queue. We also study the burstiness and correlation of the departure process. We have observed that the autocorrelation coefficients of the interdeparture time(correlogram) of the departure process may oscillated.

• The Journal of Natural Sciences
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• v.8 no.2
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• pp.83-91
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• 1996

We first obtain the departure process of a D-BMAP/Geo/1/K queue. The departure process is then exactly characterized by a k-state MMBP in order to capture the burstiness and correlation of the departure process.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.3
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• pp.1-7
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• 2017

This paper proposes a discrete logarithm algorithm that largely reduces execution times of Pollard's Rho and Brent's algorithm in obtaining ${\gamma}$ from ${\alpha}^{\gamma}{\equiv}{\beta}$(mod p). The proposed algorithm can be distinguished from the conventional Brent's algorithm by three major features: it sets an initial value as $x_0={\alpha}{\beta}$ in lieu of $x_0=1$; replaces $y=x_i$, ($i=2^k$) pointer with $y_j{\leftarrow}x_i$, ($i=2^k$, $1{\leq}j{\leq}10$) for a Queue the size 10; and detects collision of ${\beta}_{\gamma}$, ${\beta}_{{\gamma}^{\prime}}$, ${\beta}_{{\gamma}^{-1}}$ instead of ${\beta}_{\gamma}$. This Queue method has reduced the execution time of Pollard's Rho algorithm with $x_0=y_0=1$ by 65.02%, and that of Brent's algorithm with $x_0=1$ by 47.80%.

• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.2
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• pp.31-44
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• 1997

This paper presents an approximate analytical model to estimate the mean packet walting times at the stations in the IEEE 802, 6 subnetwork of a metropolitan area network. Each station is modeled as a two queue single server system, which serves data packets and requests from downstream stations according to the DQDB protocol. The model estimates the mean waiting time of the requests and in turn, using the discrete time work conservation law, estimates the mean waiting time for packets. Simulation experiments shows that the model accurately works even under very high traffic loads.

• Journal of Korea Society of Industrial Information Systems
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• v.25 no.1
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• pp.89-99
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• 2020

In this paper, we consider a dyadic server control policy that combines workload control and single vacation. Customer arrives at the system with Bernoulli process, waits until his or her turn, and then receives service on FCFS(First come first served) discipline. If there is no customer to serve in the system, the idle single server spends a vacation of discrete random variable V. If the total service times of the waiting customers at the end of vacation exceeds predetermined workload threshold D, the server starts service immediately, and if the total workload of the system at the end of the vacation is less than or equal to D, the server stands by until the workload exceeds threshold and becomes busy. For the discrete-time Geo/G/1 queueing system operated under this dyadic server control policy, an idle period is analyzed and the steady-state queue length distribution is derived in a form of generating function.

• Journal of Construction Engineering and Project Management
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• v.4 no.2
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• pp.31-40
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• 2014

The management of vehicular supply of "perishable" construction material, such as concrete mixes, faces a series of uncertainties such as weather, daily traffic patterns and accidents. Presented in this paper is a logistics control model for managing a hauling fleet with interrelated processes at both ends and queue capacities. Discrete event simulation is used to model the complex interactions of production units and the randomness of the real world. Two alternative strategies for ready mix concrete delivery, with and without an off-site waiting queue, are studied to compare supply performance. Secondly, the paper discusses the effect of an agent-based GPS tracking system providing real-time travel data that lessens the uncertainty of trucking time. The results show that the combination of GPS information with off-site queuing reduces productivity loss and process wastes of concrete placement as well as the idleness of supply trucks when crew or pump experience an unexpected stoppage.

• ETRI Journal
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• v.25 no.4
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• pp.238-246
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• 2003

This paper introduces the modeling and analysis of a discrete-time, two-phase queueing system for both exhaustive batch service and gated batch service. Packets arrive at the system according to a Bernoulli process and receive batch service in the first phase and individual services in the second phase. We derive the probability generating function (PGF) of the system size and show that it is decomposed into two PGFs, one of which is the PGF of the system size in the standard discrete-time Geo/G/1 queue without vacations. We also present the PGF of the sojourn time. Based on these PGFs, we present useful performance measures, such as the mean number of packets in the system and the mean sojourn time of a packet.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.1
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• pp.53-63
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• 2018

In this paper, we analyze the waiting time of a queueing system with D-BMAP (discrete-time batch Markovian arrival process) and D-policy. Customer group or packets arrives at the system according to discrete-time Markovian arrival process, and an idle single server becomes busy when the total service time of waiting customer group exceeds the predetermined workload threshold D. Once the server starts busy period, the server provides service until there is no customer in the system. The steady-state waiting time distribution is derived in the form of a generating function. Mean waiting time is derived as a performance measure. Simulation is also performed for the purpose of verification and validation. Two simple numerical examples are shown.

• Journal of the Korean Operations Research and Management Science Society
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• v.19 no.3
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• pp.235-241
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• 1994

We consider a B/G/1 queueing with vacations, where the server closes the gate when it begins a vacation. In this system, customers arrive according to a Bernoulli process. The service time and the vacation time follow discrete distributions. We obtain the distribution of the number of customers at a random point in time, and in turn, the distribution of the residence time (queueing time + service time) for a customer. It is observed that solutions for our discret time B/G/1 gated vacation model are analogous to those for the continuous time M/G/1 gated vacation model.

• Journal of the Korea Society of Computer and Information
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• v.9 no.3
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• pp.163-169
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• 2004

In this paper, a conventional key exchange method simply performs the key exchange setup step based on discrete algebraic subjects. But the mutual-authentication procedure of wireless PKI for reducing authentication time uses an elliptical curve for a key exchange setup step. Proposed handover method shows reduced handover processing time than conventional method since it can reduce CRL retrieval time. Also, we compared proposed authentication structure and conventional algorithm. and simulation results show that proposed authentication method outperforms conventional algorithm in all environment regardless of call arrival rate. queue service rate. queue size.