• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.276.2-278
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• 2000

In a recent years, a number of approaches have been studied, including passive, active, and hybrid mode-locking of semi-conductor lasers for short pulse generation and research has been devoted to achieve low timing-jitter operation since the timing jitter is unfavorable for system applications. Among the methods of mode locking, passive mode locking does not need external rf drives, and therefore the operation and fabrication procedures are simplified. In spite of these attractive advantages of passive mode-locked laser, it has critical drawbacks such as large timing jitter and the difficulty in synchronization with external circuits. Their inherent large timing jitter value was shown to be suppressed to certain levels by means of hybrid mode-locking technique$^{(1)}$ , where the saturable absorber section was modulated by an external signal with the cavity round trip frequency. Furthermore, the subharmonic mode-locking (SHML) technique alleviates the restrictions of high speed driving electronics. It has been demonstrated experimentally$^{(1)}$ that the hybrid subharmonic mode-locking technique has lead to significant reduction of the timing jitter. (omitted)

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1518-1520
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• 2002

Purpose of this research compares best transfer speed about applied frequency and voltage using characteristic of $L_1-B_4$ mode and $L_1-B_8$ mode linear ultrasonic motor that use piezoelectric effect. By method of study, analyzed best transfer speed measuring and comparison load status that use actuality telephone card in $L_1-B_4$ mode linear ultrasonic motor and no-load status of $L_1-B_8$ mode linear ultrasonic motor. Experiment result is applied frequency(58.4Hz) in $L_1-B_4$ mode linear ultrasonic motor (load state) and the best transfer speed by 19.8[cm/s] at applied voltage(56V) point. Also, $L_1-B_8$ mode linear ultrasonic motor (no-load state) is best transfer speed by applied frequency(27.9kHz) and 32.96[cm/s] at applied voltage (50V) point.

• The Journal of the Acoustical Society of Korea
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• v.16 no.2
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• pp.80-88
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• 1997

In this paper, the implementation of audio/data processor using ETRI DSP to support analog mode in digital/analog dual mode mobile phone is presented. Audio/data processor performs the wideband data processing, audio signal processing, demodulation function, and data rate conversion when it is operated in analog mode. These functions are programmed in assembly language, and then loaded to ETRI DSP together with vocoder program for the digital mode operation. This is a very efficient implementation of the dual mode cellular phone ASIC since the vocoder for the digital mode and audio/data processor for the analog mode are programmed together in the same hardware.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.2
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• pp.99-109
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• 1999

This paper is concerned with instability of flow fields which are dominated by the entropy mode with the presence of usual acoustic and vortical modes. These combined modes lead to nonlinear unstable waves which may occur in automobile, aircraft, or rocket engines. In this study instability in a side-burning rocket is investigated. It is shown that the energy growth rate parameters increase with an increase of the energy growth factor. The energy growth rate parameters for turbulent flows are larger than those for laminar flows. It is further shown that unstable wave motions for the high-temperature side-burning rocket are dictated mostly by the entropy mode, somewhat by the vortical mode, and least by the acoustic mode.

• Journal of Sasang Constitutional Medicine
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• v.29 no.3
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• pp.224-231
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• 2017

Objectives Several researches have been done to develop instruments or questionnaire for diagnosis of sasang constitution. In this study, we developed a user-friendly web system to enhance the utilization of KS-15. Methods The KS-15 Web application was constructed by considering the responsive web design and easy survey answer. This system is designed only to authorized users for security purposes, and provides two modes, simple mode and expert mode, depending on the purpose of using the system. A simple mode do not keep user information and survey answer in the database. An expert mode support management of patients, diagnosis of sasang constitution and statistical functions. Results & Conclusions The developed KS-15 system can be operated from any smart device's web browser. In order to use information in clinic field, it was developed so that it can be accessed only by authorized users. It can be divided into an account which can use only simple mode and an account which can use expert mode by using a difference in access authority. These functions can enhance the applicability of sasang constitution in real life such as clinical or education.

• International Commerce and Information Review
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• v.11 no.4
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• pp.183-214
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• 2009

We identify key theoretical approaches, constructs, and primary variables of interest that exist in the foreign market entry mode articles. This provides fertile ground for continued development in our foreign market entry mode research. Using the integrated framework, this paper examines the determinants of foreign market entry mode choice by Korean firms and the impact of the entry mode choice on performance in a unified model. Using a database of KIS-VALUE in Korea from 2003 to 2005, we find that the hypothesized effects of related factors on entry modes are partially supported.

• Journal of the Optical Society of Korea
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• v.9 no.2
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• pp.54-58
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• 2005

A novel mode analysis method and differential mode delay measurement technique for a multimode optical fiber based on optical frequency domain reflectometry has been proposed for the first time. We have used a conventional OFDR with a tunable external cavity laser and a Michelson interferometer. A few-mode optical multimode fiber was prepared to test our proposed measurement technique. The differential mode delay (DMD) of the sample fiber was measured to be 16.58 ps/m with a resolution of 1.5 ps/m. We have also compared the OFDR measurement results with those obtained using a traditional time-domain measurement method.

• Proceedings of the Acoustical Society of Korea Conference
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• 1996.06a
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• pp.9-12
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• 1996

This paper introduces an analysis of the non-axisymmetric mode due to in-plane vibration of an annular type piezoelectric actuator using FEM(Finite Element Method). The actuator is used as stator of ultrasonec motor. The freqrency charecterisrics and non-axisymmetric mode of the annular piezoelectric acruator are considered at a steady-state condition. The non-axisymmetric mode is occured by two sinusodial voltage sources with $\pi$/2 phase difference on the time domain. The resonant frequency of non-axisymmetric of non-axisymmetric mode is 60.358 kHz and 59.880 kHz for calculation and measurement, respectivly. The error was 0.8% between calculation and measurement. The revolution of the non-axisymmetric mode for actuator is analized at a period of exciting voltage sources using annimation. It is confirmed that the actuator has an usefulness as the stator of ultrasonic motor and the preposed method has a properity.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2290-2292
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• 2000

Robustness characteristics to the modelling imprecision and some disturbances could be achieved in sliding mode control. However, there are drawbacks such as discontinuous control and chattering. Recently, many researches have been developing to solve such the problems. In sliding mode control, overall control input could be divided into two parts which are equivalent control input and sliding mode control input. Sliding mode control input is a function of the switching surfaces and can be designed with their linear combinations. In this paper, the sliding mode control input is designed by TSK fuzzy model. The proposed method gives the continuous sliding control input and reject the chattering phenomenon.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.3
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• pp.231-239
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• 2017

A novel current control technique with fast response and application in an unbalanced system is proposed in this paper. Contrary to the conventional PI and dead-beat current control techniques, the proposed method is adopted to the valley current mode control (VCMC) and average current mode control (ACMC) methods to overcome the phase delay caused by conventional methods. The advantages of the proposed system are simplicity of structure and ease of implementation. The VCMC and ACMC methods are established and applied to the buck converter, boost converter, three-phase PWM converter, and three-phase inverter. The control performances of the proposed systems are shown by computer simulations and verified by experimental results.