• Wind and Structures
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• v.10 no.4
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• pp.399-400
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• 2007

• Proceedings of the Korea Society of Design Studies Conference
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• 2004.10a
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• pp.198-199
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• 2004

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.11
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• pp.441-489
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• 1998

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.1
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• pp.62-68
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• 1999

The attitude of a vehicle can be precisely determined using GPS carrier phase measurements from more than two antennas attached to a vehicle and an efficient integer ambiguity resolution technique. Many methods utilizing the known baseline length as a constraint of independent elements of integer ambiguities are proposed to resolve integer ambiguity at real time. Three-dimensional search space is reduced to two-dimensional search space with this constraint. Thus the true integer ambiguity can be easily determined with less computational burden and fewer number of measurements. But there are still strong requirements for the real time integer ambiguity resolution, which uses single epoch measurement of long baseline. In this paper, a new constraint from the geometry of multiple baselines is derived. With this new constraint, two-dimensional search space is further reduced to one-dimensional search space. It makes possible to determine integer ambiguity with single epoch measurement. The proposed method is applied to real data to show its effectiveness.

• Journal of The Korean Astronomical Society
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• v.43 no.4
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• pp.135-139
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• 2010

We present the result of our investigation on the impact of the low Solar abundance of Asplund and collaborators (2004) on the derived ages for the oldest star clusters based on isochrone fittings. We have constructed new stellar models and corresponding isochrones using this new solar mixture with a proper Solar calibration. We have found that the use of the Asplund et al. (2004) metallicity causes the typical ages for old globular clusters in the Milky Way to be increased roughly by 10%. Although this may appear small, it has a significant impact on the interpretation for the formation epoch of Milky Way globular clusters. The Asplund et al. (2004) abundance may not necessarily threaten the current concordance cosmology but would suggest that Milky Way globular clusters formed before the reionization epoch and before the main galaxy body starts to build up. This is in contrast to the current understanding on the galaxy formation.

• Journal of applied mathematics & informatics
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• v.6 no.2
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• pp.553-568
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• 1999

This paper is of concern to queueing analysis of the dynamic rate leaky bucket(LB) scheme in which the token generation interval changes according to the buffer state at a token generation epoch. Cell arrivals are assumed to follow a Markovian arrival process (MAP) which is weakly dense in the class of the stationary point processes. By using the embedded Markov chain method we obtain the probability distribution of the system state at a token generation epoch and an arbitrary time. Some simple numerical examples also are provided to show the effects of the proposed LB scheme.

• Journal of Korean Institute of Industrial Engineers
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• v.27 no.1
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• pp.11-17
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• 2001

We consider the M/G/1 with Bernoulli feedback, where the served customers wait in the feedback queue for rework with probability p. It is important to decide the moment of dispatching in feedback systems because of the dispatching cost for rework. Up to date, researches have analyzed for the instantaneous-dispatching model or the case that dispatching epoch is determined by the state of feedback queue. In this paper we deal with a dispatching model whose dispatching epoch depends on main queue. We adopt supplementary variable method for our model and a numerical example is given for clarity.

• Journal of the Korean Operations Research and Management Science Society
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• v.18 no.3
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• pp.1-12
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• 1993

Several alternative manufacturing control strategies are under study in the literature. They are, specifically, push system, pull system, conwip system, and as a special case, infinite buffer system. We focus on modeling, comparison analysis and design of these systems. The event epoch sequences of each system are generated which also enable us to compare their performance. Then the stochastic monotonicity of these enent epoch sequences in several important design parameters are established through the structure of the generalized semi-Markov schemes on which they are based. Finally, we solve the stochastic optimization problem which minimizes these event epochs. Our results supplement the applicability of some previously known results in the literature.

• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.4
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• pp.167-172
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• 1997

We present a procedure which finds the probability distribution of number of customers accumulated when the server ends a vacation in the Geo/G/1 gated queueing system, where the service for a customer and the vacation, respectively, takes one slot time. The pp. g. f. for the number of customers accumulated at the gate closing epoch is obtained as a recursive form. The full probabilities, then, are derived using an iterative procedure. This system finds an application in a packet transmitting telecommunications system where the server transmits(serves) packets(customers) accumulated at a gate closing epoch, and takes one slot time vacation thereafter.

• Journal of the Korean Operations Research and Management Science Society
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• v.39 no.3
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• pp.1-5
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• 2014

We study the paper Zhernovyi and Zhernovyi [Zhernovyi, K.Y. and Y.V. Zhernovyi, "An $M^{\Theta}/G/1/m$ system with two-threshold hysteresis strategy of service intensity switching," Journal of Communications and Electronics, Vol.12, No.2(2012), pp.127-140]. In the paper, authors used the Korolyuk potential method to obtain the stationary queue length distribution. Instead, our note makes an attempt to apply the most frequently used methods : the embedded Markov chain and the supplementary variable method. We derive the queue length distribution at a customer's departure epoch and then at an arbitrary epoch.