• Journal of the Korean Operations Research and Management Science Society
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• v.40 no.1
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• pp.1-4
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• 2015

This paper presents a heuristic approach to derive the Laplace-Stieltjes transform (LST) and the probability generating function (PGF) of the waiting time distributions of a continuous- and a discrete-time GI/G/1 queue, respectively. This is a new idea to derive the well-known results, the waiting time distribution of GI/G/1 queue, in a different way.

• Structural Engineering and Mechanics
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• v.68 no.2
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• pp.215-226
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• 2018

In this article, the theory of fractional order two temperature generalized thermoelasticity is employed to study the wave propagation in a fiber reinforced anisotropic thermoelastic half space in the presence of moving internal heat source. The whole space is assumed to be under the influence of gravity. The surface of the half-space is subjected to an inclined load. Laplace and Fourier transform techniques are employed to solve the problem. Expressions for different field variables in the physical domain are derived by the application of numerical inversion technique. Physical fields are presented graphically to study the effects of gravity and heat source. Effects of time, reinforcement, fractional parameter and inclination of load have also been reported. Results of some earlier workers have been deduced from the present analysis.

• Steel and Composite Structures
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• v.22 no.2
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• pp.369-386
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• 2016

In this work, the two-dimensional generalized magneto-thermoelastic problem of a fiber-reinforced anisotropic material is investigated under Green and Naghdi theory of type III. The solution will be obtained for a certain model when the half space subjected to ramp-type heating and traction free surface. Laplace and exponential Fourier transform techniques are used to obtain the analytical solutions in the transformed domain by the eigenvalue approach. The inverses of Fourier transforms are obtained analytically. The results have been verified numerically and are represented graphically. Comparisons are made with the results predicted by the presence and absence of reinforcement and magnetic field.

• Journal of the Korean Operations Research and Management Science Society
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• v.18 no.3
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• pp.179-186
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• 1993

We derive the arbitrary time point system size distribution of M/ $G^{B}$1 queue in which late arrivals are not allowed to join the on-going service. The distribution is given by P(z) = $P_{4}$(z) $S^{*}$ (.lambda.-.lambda.z) where $P_{4}$ (z) is the probability generating function of the queue size and $S^{*}$(.theta.) is the Laplace-Stieltjes transform of the service time distribution function. We also derive the distribution of the service siez at arbitrary point of time. time.

• Journal of the Korean Operations Research and Management Science Society
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• v.29 no.4
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• pp.1-10
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• 2004

In this paper we study bounds for characteristics of stationary waiting times in (max, +)-linear systems with a Poisson arrival process. which are prevalent in manufacturing systems, kanban systems, cyclic and acyclic fork-and-join type systems, finite or infinite capacity tandem queues with various kinds of blocking, transportation systems, and telecommunication networks, and so on. Recently, some results on series expansion for characteristics, such as higher moments, Laplace transform, and tail probability, of transient and stationary waiting times in a class of (max, +)-linear systems via Taylor series expansions have been studied. In order to overcome the computational complexity in those results, we consider bounds for characteristics of stationary waiting times using valuable stochastic ordering results. Some numerical examples are also provided.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.388-393
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• 1988

New circuit D-Q transformation concept is introduced to analyze AC converters such as inverters, rectifiers and cyclo-converters with ease. The equivalent linear time invariant circuit is obtained by substituting switches with equivalent turn-ratio variable transformers and changing balanced AC reactors into equivalent DC reactors combined by gyrators. This circuit enables us to utilize the powerful linear system analysis techniques such as Laplace transform otherwise which could not be applied to the time varying switching systems. Direct substitution of switches of DC converters with transformers is shown as a preliminary. Then the modeling procedure is shown for a controlled rectifier-inverter circuit. Finally an analysis example is proposed for a buck-boost inverter and the result is compared with the conventional approach. This approach is applicable to all AC converter families to determine the AC transfer functions and the DC operating points. It is identified that the switching systems are equivalent to the RLC filter circuits with transformers and gyrators.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1036-1041
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• 1993

The tip of the flexible robot arm has to be controlled by the active control reducing vibration because it has residual vibration after getting to desired position. This paper presents an end-point position control of a 1-link flexible robot arm having tip mass by the PID control algorithm. The system is composed of a flexible arm with tip mass, dc servomotor and ballscrew mechanism under translational motion. The feedback signal composed of the tip displacement measured by laser sensor, estimated velocity and acceleration is used to control the base motion. Theoretical results are obtained by applying the Laplace transform and the numerical inversion method to the governing equations. After the flexible robot arm reaches to. the desired position, the residual vibration is controlled by the PID algorithm. This paper gives the simulation and experimental results of end-point responses according to changing tip-mass and arm length. And this algorithm shows good effects of reducing the residual vibration. Approximately, theoretical response is in good agreement with experimental one.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.96.1-96
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• 2001

This paper is shown that the impulse and unit step response of second-order system can be computed by the analytic methods using Laplace transform. Also, the transient response specifications are explicitly formulated by the peak undershoot and maximum overshoot of the step response. Three different second-order systems are investigated: prototype system, system with LHP(left half plane) real zero, and system with RHP(right half plane) real zero. Based on these analytic results, this paper presents the sufficient and necessary conditions for the second-order linear SISO(single-input/single-output) stable system to have the nonovershooting or monotone nondecreasing step response.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.9-13
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• 1997

This parer is a study on the inverse dynamics of a one-link flexible robot arm which is controlled by translational base motion. The system is composed of a flexible arm, a base for driving arm, a DC servomotor, and a computer. The arm base is moved so that the arm tip follows a desired function. The governing equations are based on the Bernoullie-Euler beam theory and solved by applying the Laplace transform method and then the numerical inversion method. Moter voltage is obtained by simulation for tip trajectory functions i. e. Bang-Bang, Cosine and Gauss Function. And, the tip motion is measured while simulation results are applying. Then the results are investigated to select most proper input and to compare their chateristics. Experimental results show the Cosine function is most proper with respect to low maximum voltage and steady state error.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.3
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• pp.623-630
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• 1995

The impulse response functions (force-strain relations) for Euler-Bernoulli and Timoshenko beams are considered. The response of a beam to a transverse impact force is numerically obtained with the convolution approach using the impulse response function obtained by Laplace transform. Using this relation, the impact force history is determined in the time domain and results are compared with those from Hertz's contact law. The parameters of timpact force model are identified using the recovered force and compared with the Hertz's contact model. In order to verify the proposed algorithm, measurements were done using an impact hammer and a steel ball drop test and these results are also compared with the simulated values.