• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.142-147
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• 2003

This paper is concerned with the experiment of vibration isolation device whit can cope with heave, pitch and roll type vibrations. This new device consists of S-shaped piezoceramic actuators supporting each corner of the plate. Small piezoceramic sensors are located at the middle of each side. This paper also presents the development and the movement of the system. The active control technique was also developed to cope with base excitation. Experimental results show that vibrations can be reduced by the new device in the case of base excitation of harmonic type.

• Speech Sciences
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• v.10 no.4
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• pp.137-147
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• 2003

Speech synthesis can classify by synthesis way, that is waveform coding, source coding and mixture coding. Specially, waveform coding is suitable for high quality synthesis. However, it is not desirable by synthesis techniques of syllable or phoneme unit because it do not separate and handles excitation and formant part. Therefore, there is a need for pitch alteration method applied in synthesis by the rule in waveform coding. This study propose about pitch alteration method that use spectrum scaling after do to flatten spectra by subband linear approximation to minimize spectrum distortion. This paper show evaluation whether show excellency of some measure compared with LPC, Cepstrum, lifter function and method that propose. estimation method seeks distribution of each flattened signal and measured degree of flattened spectra Signal flattened is normalized, So that highest point amounts to zero, and distribution of signal ,whose average is zero, is calculated. this show result that measure the spectrum distortion rate to estimate performance of method that propose. The average spectrum distortion rate was kept below the average 2.12%, so the method that propose is superiors than existent method.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.1
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• pp.1-8
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• 2003

Generally, thrust force of double-sided LPM is more powerful than that of single-sided LPM. Also, double-sided LMP can be effectively applied to the high-precision position system with its simple control scheme. However, An equality between two airgap lengths Is a necessary condition for its high performance. If a little difference between two airgaps is existed, unbalanced normal force and undesirable vibration will be generated. Additionally, even though two airgap lengths are absolutely same, undesirable vibration can be generated because the direction of instantaneous normal force on mover is changed according to excitation methods. An effect of inequality of two airgap lengths is presented in this paper. Distribution of airgap permeance vs. relative displacement is analyzed by two dimensional finite element method. Excitation From this results, current waveforms to reduce the undesirable vibration is proposed.

• Transactions of the Society of Information Storage Systems
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• v.11 no.2
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• pp.22-25
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• 2015

In this paper, we demonstrate solid-immersion lens based confocal microscopy using super-continuum generation effect. Using super-continuum generation effect, we could diversify the excitation wavelength of confocal microscopy. Further, high refractive index of solid-immersion lens would increase the resolution of confocal microscopy. As a result, by applying the super-continuum generation effect and solid-immersion lens to confocal microscopy, some problems of confocal fluorescent microscopy, the excitation wavelength and the resolution, could be overcome. To verify it, we made home-built solid-immersion lens based confocal microscopy using super-continuum generation effect, and evaluate the performance of the system.

• 연구논문집
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• s.31
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• pp.65-75
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• 2001

A dynamic model of pump having one step gearbox and two step gearbox is developed by the lumped parameter method. The model accounts for shafts, ball bearings and journal bearings flexibilities, gyroscopic effects and the force couplings among the transverse and torsion motions due to gearing. Excitation forces of pump having one step gearbox and two step gearbox are considered as the mass unbalance of the rotors and gear transmission error which comes from the modified tooth surface. A Campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors and the transmitted errors of the gearing are considered, shows that there are no critical speeds at the operating speeds. One step and two step gearboxes are manufactured and are estimated for vibration/noise, lubrication and performance.

• Journal of Power Electronics
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• v.10 no.4
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• pp.444-449
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• 2010

The generation of electric power using self excited induction generation (SEIG) is a viable option in remote and rural areas where grid electricity is not available. The generated voltage and frequency of these machines, however, varies with varying loads. This characteristic can be resolved either by adjusting the values of the excitation capacitance or by controlling the prime mover speed. Further, in a single-point constant power application, where the machines deliver a fixed amount of power, the electronic load controller (ELC) can be used to switch-in or switch-out a dump load whenever the consumer load decreases or increases respectively. This paper presents a detailed analysis and the design of a microcontroller based SEIG -ELC system intended for stand-alone pico hydro power generation. The simulated performance of the controller is supplemented by experimental results.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1002-1004
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• 2005

This paper describes the performance analysis and design of single-phase self-excited induction generators. In this study, it is proposed to design the proper capacitance for self-excitation and voltage regulation, also. This methods are based on the induced MMF equations between main and the auxiliary winding. For the least influence between the two capacitors, the self-excited capacitor is selected under no load condition, while the series capacitor is designed under loaded condition. For the steady state analysis, the equivalent circuit of single-phase induction generators is used as circuit modeling using the double-revolving field theory. The validity of proposal methods and designed generator system will be confirmed by experimental and computed results.

• CELLMED
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• v.12 no.3
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• pp.13.1-13.3
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• 2022

The aim of this study was to evaluate the synergistic effect of Samulnori and Ajaeng combination in music therapy. Samulnori is the Korea's most successful traditional music. The Ajaeng, Korean traditional string instrument, generally plays the bass part in ensemble music. However, we have tried a new kind of musical style. (As you can see in the Youtube, https://youtu.be/QHIciJTTY0w). Samulnori and Ajaeng combination of our style have not been tried by any other musicians in Korea. Results from this study showed that Samulnori-induced excitation and Ajaeng-induced dynamics probably contributed to the synergistic effect of Samulnori and Ajaeng.

• KIEE International Transactions on Power Engineering
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• v.3A no.1
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• pp.17-26
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• 2003

In this paper, the comparative steady-state operating performance analysis algorithms of the stand-alone single-phase self-excited induction generator (SEIG) is presented on the basis of the two nodal admittance approaches using the per-unit frequency in addition to a new state variable de-fined by the per-unit slip frequency. The main significant features of the proposed operating circuit analysis with the per-unit slip frequency as a state variable are that the fast effective solution could be achieved with the simple mathematical computation effort. The operating performance results in the simulation of the single-phase SEIG evaluated by using the per-unit slip frequency state variable are compared with those obtained by using the per-unit frequency state variable. The comparative operating performance results provide the close agreements between two steady-state analysis performance algorithms based on the electro-mechanical equivalent circuit of the single-phase SEIG. In addition to these, the single-phase static VAR compensator; SVC composed of the thyristor controlled reactor; TCR in parallel with the fixed excitation capacitor; FC and the thyristor switched capacitor; TSC is ap-plied to regulate the generated terminal voltage of the single-phase SEIG loaded by a variable inductive passive load. The fixed gain PI controller is employed to adjust the equivalent variable excitation capacitor capacitance of the single-phase SVC.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.10
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• pp.3079-3094
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• 1996

Recently, the high-precision vibration attenuation technology becomes the essence fo the seccessful development of high-integrated and ultra-precision industries, and is expected to continue playing a key role in the enhancement of manufacturing technology. Vibration isolation system using an air-spring is widely employed owing to its excellent isolation characteristics in a wide frequency range. It has, however, some drawbacks such as low-stiffness and low-damping features and can be easily excited by exogenous disturbances, and then vibration of table is remained for a long time. Consequently, the need for active vibration control for an air-spring vibration isolation system becomes inevitable. Furthermore, for an air-spring isolation table to be successfully employed in a variety of manufacturing sites, it should have a guaranteed robust performance not only to exogenous disturbances but also to uncertainties due to various equipments which might be put on the table. In this study, an active vibration suppression control system using H.inf. theory is designed and experiments are performed to verify its robust performance. An air-spring vibration isolation table with voice-coil-motors as its actuators is designed and built. The table is modeled as 3 degree-of-freedom system. An active control system is designed based on $H_\infty$control theory using frequency-shaped weighting functions. Analysis on its performance and frequency responce properties are done through numerical simulations. Robust characteristics of$H_\infty$ control on disturbances and model uncertainties are experimentally verified through (i) the transient response to the impact excitation of the table, (ii) the steady-state response to the harmonic excitation, and (iii) the response to the mass change of the table itself. An LQG controller is also designed and its performance is compared with the $H_\infty$ controller.