• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.1
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• pp.32-39
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• 2014

Traveling wave generation in a ring type stator has been studied. The basic working principle to create traveling wave has been modelled by the superposition of two orthogonal standing waves. Theoretical analysis shows that the length to radius ratio affects the frequency gap between two pseudo orthogonal modes used to create traveling wave. FEM simulation is then discussed and applied to validate the analytical model. At last, a possible optimal solution is reported with FEM verification.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1614-1621
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• 2008

I accomplished a curve section traveling safety assessment analysis followed with railway condition for elevation of a curve passage speed of train utilizing trail analysis model. As a result, we confirmed that excess cant influence in badly traveling safety of train followed with cant change and cant shortage influence in badly traveling safety in case of large a curve radius and traveling safety of originally a curve section is most wrong. Also we confirmed that shortage of relief a curve length influence in badly traveling safety followed with change of relief a curve length.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.12
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• pp.1331-1336
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• 2014

In this study, we have implemented a PAM(Power Amplifier Module) with 25W output power using by cooperate divider/Combiner circuit in X-band to minimize combine loss on a Al2O3 substrate. The PAM(Power Amplifier Module) is consisted of MMIC and 10way traveling wave divider/Combiner with proposed structure what have showed that 45.2dBm output power, 16dB gain, PAE 26 % and 17dBc@44dBm IMD3 characteristics. This combine/divider structure can be used when multistage passive divider and combiner needs. especially, power amplifier with very compact size.

• The Journal of the Korea Contents Association
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• v.20 no.11
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• pp.636-643
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• 2020

The differential evolution algorithm is one of the meta-heuristic techniques developed to solve the real optimization problem, which is a continuous problem space. In this study, in order to use the differential evolution algorithm to solve the traveling salesman problem, which is a discontinuous problem space, a random key representation method is applied to the differential evolution algorithm. The differential evolution algorithm searches for a real space and uses the order of the indexes of the solutions sorted in ascending order as the order of city visits to find the fitness. As a result of experimentation by applying it to the benchmark traveling salesman problems which are provided in TSPLIB, it was confirmed that the proposed differential evolution algorithm based on the random key representation method has the potential to solve the traveling salesman problems.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.12
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• pp.126-132
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• 1999

The paper presents the modeling and optimal control for the reduction of transverse vibration of simply supported beam under a moving mass. The equations of motion are derived by using assumed mode method. The coriolis and centripetal accelerations are accommodated in the equations of motion to account for the dynamic effect of the traveling mass. In order to reduce the transverse vibration of the beam, an optimal controller with full state feedback is designed based on the linearized equations of motion. The optimal actuator locations are determined with the evaluation of an optimal cost functional defined by the worst initial condition with the trade-off of controlled mode performance. Numerical simulations are performed with respect to various velocities and different traveling masses. Even if the velocity of the traveling mass reaches to the critical speed which can cause the resonance of the beam, the controller with two piezoelectric actuators shows the excellent performance under severe time-varying disturbances of the system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.192-192
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• 2008

This paper represents a piezoelectric ultrasonic linear motor by traveling wave. The motor which is composed of two piezo ceramics, elastic body, and connecting tip is driven by the frictional force between the connecting tip and the linear motion guide. longitudinal and flexural vibrations are made by traveling wave which is generated when the ultrasonic electrical signals with 90 degree phase difference are applied to two ceramics. These vibrations contribute to elliptical motion by mixed mode between longitudinal and transverse mode. A linear movement can be easily obtained by using the elliptical motion. In this paper, the piezoelectric actuator has been intensively simulated by using ATILA to achieve an optimized elliptical motion of it. We could get the elliptical motion from actual experiment through the simulated result.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.1
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• pp.105-111
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• 2004

DNA computing has been using to solve TSP (Traveling Salesman Problems). However, when the typical DNA computing is applied to TSP, it can`t efficiently express vertices and weights of between vertices. In this paper, we proposed ACO (Algorithm for Code Optimization) that applies DNA coding method to DNA computing to efficiently express vertices and weights of between vertices for TSP. We applied ACO to TSP and as a result ACO could express DNA codes which have variable lengths and weights of between vertices more efficiently than Adleman`s DNA computing algorithm could. In addition, compared to Adleman`s DNA computing algorithm, ACO could reduce search time and biological error rate by 50% and could search for a shortest path in a short time.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.2
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• pp.222-227
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• 2006

Recently the research for Traveling Salesman Problem (TSP) using DNA computing with massive parallelism has been. However, there were difficulties in real biological experiments because the conventional method didn't reflect the precise characteristics of DNA when it express graph. Therefore, we need DNA sequence generation algorithm which can reflect DNA features and reduce biological experiment error. In this paper we proposed a DNA sequence generation algorithm that applied DNA coding method of evolution model to DNA computing. The algorithm was applied to TSP, and compared with a simple genetic algorithm. As a result, the algorithm could generate good sequences which minimize error and reduce the biologic experiment error rate.

• Nuclear Engineering and Technology
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• v.54 no.9
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• pp.3540-3550
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• 2022

The supercritical carbon dioxide (S-CO₂) Brayton cycle is an important energy conversion technology for the fourth generation of nuclear energy. Since the printed circuit heat exchanger (PCHE) used in the S-CO₂ Brayton cycle has narrow channels, Rayleigh-Bénard (RB) convection is likely to exist in the tiny channels. However, there are very few studies on RB convection in supercritical fluids. Current research on RB convection mainly focuses on conventional fluids such as water and air that meet the Boussinesq assumption. It is necessary to study non-Boussinesq fluids. PRB convection refers to RB convection that is affected by horizontal incoming flow. In this paper, the computational fluid dynamics simulation method is used to study the PRB convection phenomenon of non-Boussinesq fluid-supercritical carbon dioxide. The result shows that the inlet Reynolds number (Re) of the horizontal incoming flow significantly affects the PRB convection. When the inlet Re remains unchanged, with the increase of Rayleigh number (Ra), the steady-state convective pattern of the fluid layer is shown in order: horizontal flow, local traveling wave, traveling wave convection. If Ra remains unchanged, as the inlet Re increases, three convection patterns of traveling wave convection, local traveling wave, and horizontal flow will appear in sequence. To characterize the relationship between traveling wave convection and horizontal incoming flow, this paper proposes the relationship between critical Reynolds number and relative Rayleigh number (r).

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.48-51
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• 2000

The traveling salesman problem with precedence relations (TSPPR) is harder than general traveling salesman problem. In this paper we propose an efficient genetic algorithm (GA) to solve the TSPPR. The key concept of the proposed genetic algorithm is a topological sort (TS). The results of numerical experiments show that the proposed GA approach produces an optimal solution for the TSPPR.