• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.2
• /
• pp.61-67
• /
• 1998

Dynamic stability in rotation of the head drum of digital VCR is very important due to the nature of high rotation speed and small angular inertia. Therefore special considerations on reducing the unbalance and assuring the stability are required the design and manufacturing process. In this paper, newly developed digital head drum is introduced. And advanced methods in analyzing and reducing the unbalance is suggested. LDV(Laser Doppler Vibrometer) was used as a measurement system verifying our modeling and new method for balancing. Experiments show that the theoretical data estimated by modeling of shaft bending caused by unbalance mass and the measured data are almost identical. The deflection was reduced to 30％ by applying the suggested balancing method.

• The Journal of the Korean dental association
• /
• v.19 no.4 s.143
• /
• pp.347-352
• /
• 1981

This experiment was performed to estimate the changes on blood flow of the oral structures in hemorrhagic shock. Rabbits were anesthetized by intravenous injection of nembutal(30mg/kg). The Femoral artery was exposed and cannulated with polyethylene tubing filled with heparinized saline. Hypovolemic shock was induced by collecting the bloos of which amount was equaled as 2 % of body weight through arterial cannula for about 30 minutes. During hemorrhage, arterial blood pressure was recorded on recorder. In hypovolemic shock, arterial blood pressure decreased from 116.2±4.1 mmHg to 62.6±4.0 mmHg. Distribution of blood flow in oral tissues decreased to 30-50 % of control group. But blood flow of the masseter muscle was increased and the mandibular angle was not changed.

• Journal of Electrical Engineering and Technology
• /
• v.1 no.1
• /
• pp.35-41
• /
• 2006

This paper presents a new numerical algorithm for fault location estimation and for faults recognition based on the synchronized phasors. The proposed algorithm is based on the synchronized phasor measured from the synchronized PMUs installed at two-terminals of the transmission lines. In order to discriminate the fault type, the arc voltage wave shape is modeled numerically on the basis of a great number of arc voltage records obtained by transient recorder. From the calculated arc voltage amplitude it can make a decision whether the fault is permanent or transient. The results of the proposed algorithm testing through computer simulation are given.

• Proceedings of the KIEE Conference
• /
• 2002.07a
• /
• pp.235-237
• /
• 2002

Whenever the large-capacitor and high-voltage pump motor is opened and closed, the power factor improvement condenser and the low-voltage equipment are often damaged by the sparking and the on-off power serge. In order to find the reason and resolve the problem, we have installed a transition wave recorder for obtaining the transient on-off power serge wave and a power disturbance analyzer for long-time monitoring. In this way we measured and analysed the condition of the high-voltage pump motor whenever it is opened and closed.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.8
• /
• pp.1595-1604
• /
• 2009

An Optical disk driver is used in many electronic products besides the computers. In particular, the demands are recently increased as an optical disk player/recorder in the mobile products such as camcorder, portable player or in the home theater appliances, etc. However, the more the mobility is emphasized, the more the optical disk player is exposed to the disturbance inputs. For reducing the possibility of malfunction of the optical disk, we propose a nonlinear controller using the disturbance detecting algorithm based on the Kalman filter. Actual experiments were executed to verify the performance of the proposed method. The proposed method controls the tracking error signal within ${\pm}0.1{\mu}m$.

• Electronics and Telecommunications Trends
• /
• v.27 no.4
• /
• pp.123-129
• /
• 2012

최근 교통사고가 발생하는 경우, 사고 발생의 책임 소재에 대한 판단을 용이하게하고, 사고예방의 효과가 높은 이유로 택시, 버스와 같은 대중교통 시설과 개인 차량에 교통사고 상황을 영상으로 기록할 수 있는 차량용 영상기록 블랙박스(VEDR: Video Event Data Recorder)의 장착이 증가하고 있다. 그러나 이러한 블랙박스의 설치 및 활용에 대한 법적 규정이 미비하여 개인의 사생활 침해 가능성과 범죄에의 악용 우려가 높다. 본고에서는 차량용 블랙박스의 사용과 함께 발생할 수 있는 보안적인 문제점들을 살펴보았다. 특히 차량용 블랙박스에서 발생할 수 있는 보안적인 문제들 중에서 현재 사회적으로 가장 이슈가 되고 있는 블랙박스에 저장된 데이터의 위 변조 문제와 개인의 프라이버시 보호 문제를 중심으로 살펴보았다. 또한 이러한 보안 문제와 관련한 국내 외의 법률 동향을 살펴보았으며, 향후 제정될 이러한 법률들을 지원하기 위하여 보완하여야 할 문제와 추가로 고려되어야 하는 문제 등을 함께 살펴보았다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.98-101
• /
• 2001

Linear motor feature a direct connection to the machine tool, therefore a direct route for heat transfer. The heat dissipation of linear motor machine is affected by the maximum temperature rise of the primary part, coil and the cooling method. To minimize temperature induced dimension changes and decrements of performance, linear motor machine require effective cooling mechanism. To evaluate cooling performance of existing linear motor machine, some experiments about temperature profile are performed using thermocouple recorder. Due to the lack of information about internal structure, only some finite element modeling is prepared and analyzed.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2006.06a
• /
• pp.201-204
• /
• 2006

In the side scan sonar method, use is made of the back-scattering, at low grazing angles of incidence to the seabed, of relatively high-frequency acoustic waves radiated in a fan-shaped beam from a transducer contained in a towed body. The fan beam is oriented so that the wider angle is in the vertical plane (scan range) and the narrower angle in the horizontal plane (beam width) with the axis of the beam normal to the ship track. The display of the returns is usually realized as a series of closely spaced intensity-modulated lines on a paper recorder or computer screen display. In this way a two-dimensional picture of the seabed is build up.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.414-419
• /
• 1997

Linear motor feature a direct connection to the machine tool, therefore a direct route for heat transfer. The heat dissipation of linear motor machine is affected by the maximum temperature rise of the primary part, coil and the cooling method. To minimize temperature induced dimension changes and decrements of performance, linear motor machine require effective cooling mechanism. 1'0 evaluate cooling performance of existing linear motor machine, some experiments about temperature profile are performed and evaluated using thermocouple recorder. Due to the lack of information about internal structure. only some finite element modelling is prepared and analyzed.

• Journal of KSNVE
• /
• v.8 no.1
• /
• pp.87-98
• /
• 1998

A Precise actuator in the pick-up of a DVDR/P(Digital Video Disk Recorder/Player) is required to control position accurately. Therefore, in order to develop a reliable actuator, dynamic characteristics of each part in an actuator should be examined closely. This paper presents systematic design process of an actuator using various analysis methods to confirm fundamental capability and solve performance problems related to dynamic characteristics of an actuator beforehand. Particularly, sensitivity analysis is presented through the program using mass moment of inertia and general equations of rigid body. Through the result of sensitivity analysis, important inferiority causes of actuator are selected and reduced. In the end, dynamic characteristics of manufactured actuators are improved considerably.