• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.8
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• pp.81-86
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• 2007

This paper proposes the scheme to improve the current direct load control(DLC) program by inspecting the problems of the DLC program. In order to increase the number of the customers participating DLC program, a reduction of the base incentive and an increase of the direct load control incentive are suggested based on the interruption cost of electric power considering the characteristics of load types and the introduction of demand side bidding is recommended. Secondly, the standards of power system operations is required to control DLC program efficiently for the penalty, interruption times, the number of interrupting loads, notice time for the load interruption and the periods of the DLC program contract.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.50-57
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• 2010

Various installation faults may lie in fasteners in the construction of a direct-fixation track by the top-down method. At an extreme, they may cause excessive interaction between the train and track, compromise the running safety of the train, and cause damage to the track components. Therefore, the faults need to be kept within the allowable level through an investigation of their effects on the interactions between the train and track. In this study, the vertical dynamic stiffness of fasteners in installation faults was measured based on the dynamic stiffness test by means of an experimental apparatus that was devised to feasibly reproduce gap faults. This study proposes an effective analytical model for a train-track interaction system in which most elements, except the nonlinear wheel-rail contact and some components that behave bi-linearly, exhibit linear behavior. To investigate the effect of the behavior of fasteners in gap faults in a direct-fixation track on the vehicle and track, vehicle-track interaction analyses were carried out, targeting key review parameters such as the wheel load reduction factor, vertical rail displacement, rail bending stress, and mean stress of the elastomer. From the results, it was noted that the gap faults in the concrete bearing surface of a direct-fixation track need to be limited for the sake of the long-term durability of the elastomer than for the running safety of the train or the structural safety of the track.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.97-101
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• 1999

No-till direct seeding cultivation of rice has major advantages such as saving of labor and cost by eliminating tillage, preparation of seed bed and trans-planting procedure compared to the conventional transplanting cultivation. A field experiment was conducted to evaluate the effects of straw treatment and nitrogen levels on the rice growth in no-till direct-seeding cultivation. Rice straw, vetch straw, and the mixture of both of the straws were mulched on the surface of soil before seeding while 4 levels of nitrogen fertilizer, 0, 7, 9, and 11 kkg/10a respectively, were applied at 3 split times, 3-weeks after sowing, 5-weeks after sowing and the panicle initiation stage. Mulching of vetch straw significantly reduced seedling establishment of rice which may be attributed to low oxidation-reduction potential of soil by vetch mulching treatment. Vetch straw increased the concentration of soil ammonium leading to an extension of the greenish leaf to panicle initiation stage. Agronomic nitrogen use efficiency (AD $E_{N}$) in heavy-mixed straw mulching plots was lower than other treatments. Grain yield and AU $E_{N}$ in the vetch treatment were less affected by fertilized N levels. Conclusively, it is suggested that heavy straw mulching was not efficient for rice seedling establishment and nitrogen usage.e.

• Journal of the Korean Society for Railway
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• v.11 no.4
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• pp.398-403
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• 2008

The propulsion for locomotive application has changed from the DC motor system to the induction motor system. Although the induction motor system has almost reached the stage of maturity, this system also needs to be changed to the PM motor system for the direct drive without using reduction gear. Thus, the IPMSM (Interior buried Permanent Magnet Synchronous Motor) has been adopted to meet the locomotive driving specification. Where the wheel is directly dirven by the traction motor. In this paper, the investigation on IPMSM satisfying driving specifications for the direct drive has been performed using the advanced FEM.

• KIEAE Journal
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• v.7 no.2
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• pp.57-62
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• 2007

Recently Among indoor noises plumbing noise from supply and drain water pipe is being pointed out as a annoying noise following to floor impact noise, and it is increasing the rate to point the noise due to the following several reasons: water pressure, vibration by fabricated structures and direct noise propagation from upper floor through ceiling This study aims to analyse the characteristics of toilet stool plumbing noise in apartment bathroom which are generated by crossing plumbings and elbows. And it analyse the effect of noise reduction by soundproofing and insulations which are covered at crossing plumbings. And also analyse the characteristics of noise about a type of elbows, crossing plumbing and result of dB(A). At last it provide a fundamental data for the purpose of reduction of plumbing noise in apartment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.2
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• pp.209-215
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• 2012

This paper deals with a reduction of cogging torque and estimate of inductance for IPMSM. The flux barriers(Barrier) and the auxiliary slot(Notch) for the reduction of cogging torque was installed for increase of driving characteristic in IPMSM. The cogging torque, driving torque and inductance are analyzed by using FEM(Finite Element Method) and the results of inductance calculation are compared to experimentation ones.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.64-68
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• 1996

In this note, we propose the discrete model reduction method over disc-type analytic domains. We define Hankel singular value over the disc that is mapped by standard bilinear mapping. And GSPA(generalized singular perturbation approximation) and DT(direct truncation) are generalized to GSPA and DT over a disc. Furthermore we show that the reduced order model over a smaller domain has a smaller L$_{\infty}$ norm error bound..

• Journal of the Korean Chemical Society
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• v.28 no.2
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• pp.130-134
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• 1984

The polarographic behavior of benzeneazoresorcinol (BAR) in acetonitrile as an aprotic solvent has been investigated by direct current polarography and controlled-potential coulometry. The reduction of BAR in $1.0{\times}10^{-2}$M tetraethylammonium perchrolate solution proceeds along four one-electron steps to give the corresponding amine compounds. Each reduction wave was considerably diffusion-controlled and not completely reversible.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.170.2-170
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• 2001

In this paper, the dynamic system modeling and the state sensitivity analysis of the spin-coater system for the reduction of the vibration are proposed. In the respect of modeling, the spin-coater system is composed of components of servomotor, belt, spindle, and a supported base. Each component is defined and combined modeling is derived to 3dimensional equations. Verification of modeling is verified by experimental values of actual system in the frequency domain. By direct differentiation the constraint equations with respect to kinematic design variables, such as eccentricity of spindle, moment of inertia, torsional stiffness and damping of supported base, sensitivity equations are derived to the verified state equations. Sensitivity of design variables could be used for vibration reduction and natural frequency shift in the frequency domain. Finally, dominant design variables ...

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.6
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• pp.465-470
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• 2001

This paper considers a new weighed model reduction method using block diagonal solutions of Lyapunov inequalities. With the input and/or output weighting function, the stability of the reduced order system is guaranteed and an a priori error bound is proposed. to achieve this after finding the solutions of two Lyapunov inequalities and balancing the full order system, we find the reduced order systems using the direct truncation and the singular perturbation approximation. The proposed method is compared with other existing methods using numerical examples.