• 제어로봇시스템학회논문지
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• 제7권2호
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• pp.117-124
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• 2001

In a SRM drive, the on/off angles of each phase switch should be accurately controlled in order to control to torque and speed in a stable way, The accuracy of the switching angles is dependent upon the resolution of the encoder and the sampling period of the microprocessor. However, as the speed increase, the amount of the switching angle deviation from the preset values is also increased by the sampling period of the microprocessor. Therefore, a low cost encoder suitable for a practical and stable SRM drive is proposed and the control algorithm to provide the switching signals using the simple digital logic circuit is also presented in this paper. It is verified from the experiments that the proposed encoder and logic controller can be a powerful candidate a the practical low cost SRM drive.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.523-524
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• 2006

Successive approximation A/D converters have an advantage of small chip area and simple algorithm. We propose an improved non-redundant successive approximation register (SAR) which can be incorporated in successive approximation A/D converters. The proposed SAR validates the preset state as the $1^{st}$ reference voltage to the comparator. Two redundant clock cycles in the typical design could be eliminated in the proposed A/D converter.

• 대한가정학회지
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• 제34권4호
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• pp.309-326
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• 1996

The purpose of the study was to preset the relationships between role conflict and psychological/physical distress of dual/earner families in Pusan. the questionnaire was composed of socio-economic status, wives' work time, spouse's emotional support scale, husbands' housework participation, role conflict scale, psychologica/physical distress scale. The major findings were as follows : 1. The level of role conflict and psychological/physical distress were higher among wives than among husbands. 2. Role conflict were the most important factor affecting the level of psychological/physical distress directly. 3. Wives' psychological/physical distress were significantly affected by role conflict and socio-economic status directly. Wives' psychological/physical distress were affected by wives' work time, husbands' emotional support, husbands' housework participation indirectly. 4. Husbands' psychological distress was significantly affected by role conflict and husbands' housework participation directly. Husbands' physical distress was significantly affected by role conflict directly. Husbands' psychological/physical distress were affected by wives' work time, wives' emotional support indirectly.

• 한국항해학회지
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• 제10권2호
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• pp.11-29
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• 1986

As per the expanding needs of marine exploitation, many floating structures have been built. Among these, box-type vessel is considered as the most basic shape, to which plant barges and crane barges belong. Stability problem is very important for vessel. In order to increase transverse stability, this paper employs bulwarks along the upper deck sides of box-type vessels and the emphasis is laid upon the effect of bulwarks on transverse stability. In the present paper, the calculation method of heeling moment acting to the ship due to hydrostatic pressure is suggested, and actual procedures of the calculation for box-type vessels with bulwarks are shown. Furthermore corresponding model tests are carried out in small water tank. Through the comparison between calculated and measured values, it is confirmed that the preset calculation method is useful. And employing bulwarks on box-type vessels is very effective for increase of transverse stability at the heeling angles from about 15 degrees to about degrees.

• Journal of Power Electronics
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• 제3권3호
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• pp.167-174
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• 2003

In a switched reluctance motor drive, it is important to synchronize the stator phase excitation with the rotor position, because the position of rotor is an essential information. Although high resolution optical encoders or resolvers are used to provide a precise position information, these sensors are expensive. Moreover, in the high-speed region, switching angles are fluctuated back and forth out of the preset value, which is caused by the sampling period of the microprocessor. In this paper, a low cost analog encoder suitable for practical applications is proposed. And the control algorithm to generate switching signals using a Simple digital logic is presented. The validity of the proposed analog encoder with a proper logic controller is verified from the experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.892-894
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• 1995

This paper deals with developmeant and application of coating thickness control system in hot dip galvanizing process. According to the line conditions, such as line speed, strip size and target coating weight, a predictive preset model sets the initial oprating conditions. Referring the zine coating informations from the gauge, mean coating value controller adjusts the chamber pressure and horizontal distance between strip and air knife, while coating deviation controller adjusts the lip gap profile of the air knife. All adaptive gains are interactively calculated by numeric models based on the theoretical analysis. The operating result with this system effectively reduces the coating deviation in transverse direction as well as in longitudinal direction.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 춘계학술대회 논문집
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• pp.511-513
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• 2004

In a switched reluctance motor drive, it is important to synchronize the stator phase excitation with the rotor position, because the position of rotor is an essential information. In the high-speed region, switching angles are fluctuated back and forth out of the preset value, which is caused by the sampling period of the microprocessor. In this paper, a low cost analog encoder suitable for practical applications is proposed. The validity of the proposed analog encoder with a proper logic controller is verified from the experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 G
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• pp.3156-3158
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• 1999

Occupancy sensor is a efficient light control system which light on/off automatically and reduces the unnecessary power waste. From now the research on occupancy sensor is restricted to the selection of the appropriate place or sensor. Exist occupancy sensor changes the delay time by manually to the place or situation, so it is unreliable. The delay time can been changed by the average time of the occupied and the preset time, but it is not enough to reliable. In this paper, so to acquire the reliance the average and the standard deviation of the occupied time change the delay time automatically and protect the malfunction from the detector. And to embody it, AT89C52 microcontroller is adopted to the control circuit. It is verified by simulation and experiment results of output characteristic for randomized input.

• 한국정보전자통신기술학회논문지
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• 제13권1호
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• pp.17-26
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• 2020

As more users use mobile devices, shoulder surfing attacks have emerged as an important issue in security. According to research report, in fact, the result showed that about 30% of smartphone users are hit by shoulder surfing attacks. To this end, in this paper, we consider a shoulder surfing attack and propose a partially hidden password system to resistant to its attack. In order to help readers understand, we describe the proposed password system in more detail using one simple example. The core idea behind the proposed system is to place the user's password randomly in the specified grid instead of entering a password directly. As a result, even if an attacker makes a shoulder surfing attack to observe the password, the user can hide the preset password and defend against the attack. We also show how the security of the password system proposed in this paper is improved. In addition, even if there are consecutive shoulder surfing attacks, the security of the proposed password system is robust.

• 조명전기설비학회논문지
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• 제29권8호
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• pp.23-31
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• 2015

This paper proposes an advanced distance relaying based on the DC offset removal filter to minimize the effects of DC offset on a double circuit transmission line. The proposed DC offset removal filter uses only one cycle of data for phasor extraction computation, which does not need to preset the time constant of the DC offset component. This proposed distance relaying uses not only the residual current of the faulted circuit but also mutual current of the healthy adjacent circuit. A series of off-line test results using ATP simulation data show the effectiveness of the an advanced distance relaying.