• The korean journal of orthodontics
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• v.13 no.2
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• pp.185-192
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• 1983

The purpose of this study was to determine the mean value of overbite and overjet, and to find the correlation among overbite, overjet and relative maxillofacial structures using the data from orthodontic casts and cephalometric films of boys and girls aged from 9 to 18 years with normal occlusions. The results were obtained as follows: 1. Incisal overbite depth was decreased from Group I to Group III. 2. The highest value of correlation coefficient with incisal overbite was 0.368 of incisal angle. in Group III. 3. Overjet was not significantly correlated with the age and sex. 4. Ratio of mesiodistal diameters of upper and lower incisors was not significantly correlated with overbite and overjet.

• Journal of Ocean Engineering and Technology
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• v.13 no.4 s.35
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• pp.45-54
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• 1999

Non destructive test is applied to revise mechanical strength and assume material strength or defect of material, equipment and structure, instead of fracture test. Especially, ultrasonic test has the characteristics such as an excellent permeability high-sensitiveness to fine defect and an almost exact measurement for position, size and direction of inner defect which differ from other non destructive tests. In this study, the program is developed to evaluate optimal testing condition, to distinguish obstacle echo and defect position. This program on the basic of Ray-Tracing model shows generation and processing of ultrasonic pulse. The simulation is compared with testing in the 3 cases of an oblique angle transducer like $45^{\circ},\;60^{\circ}\;and\;70^{\circ}$. The test result for all conditions is well compared with simulation result when relative not is within $0.1{\sim}7.2%$. And the course of several echos is simply assumed through simulation.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1028-1033
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• 2004

The heat and flow characteristics in a single-phase parallel-flow heat exchanger was examined numerically to obtain its optimal shape. A response surface method was introduced to predict its performance approximately with respect to design parameters over design domain. Design parameters are inflow and outflow angle of the working fluid and horizontal and vertical location of inlet and outlet. The evaluation of the relative priority of the design parameters was performed to choose three important parameters in order to use a response surface method. A JF factor was used as an evaluation characteristic value to consider the heat transfer and the pressure drop simultaneously. The JF factor of the optimum model, compared to that of the base model, was increased by about 5.3%.

• Design & Manufacturing
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• v.6 no.2
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• pp.42-47
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• 2012

The paper deals with an analysis of an extrusion process with a divided material flow in a combined radial - backward extrusion. We have discussed the influences of tool geometry such as punch nose angle, relative gap height, die corner radius on material flow and surface expansion into can and flange region. To analyse the process, numerical simulations by the FEM and experiment by physical modeling using Al alloy as a model material have been performed. Based on the results, the influence of fixed parameters on the distribution of divided material flow and surface expansion are obtained.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.8
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• pp.673-680
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• 2015

A roll-to-roll (R2R) continuous manufacturing system for a carbon-nanotube (CNT)-/silver-nanowire (AgNW)- based large-area transparent conductive film was introduced in this study. The systemic guidelines of the R2R slot-die coating process including roll eccentricity, wrap angle, pump accuracy, and blower influence were discussed. To simulate the coating phenomenon, we investigated the governing parameters of the coating process by incorporating the estimated relative thickness that was defined by combining the viscocapillary model and volume model. By using experimental and mathematical approaches, an excellent transparent conductive layer with a $40{\Omega}/{\Box}$ sheet resistance and 88 % transmittance was obtained; moreover, a dimensionless number identifies the correlation between the transparent conductive film and the anti-reflection film.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.400-402
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• 1994

This paper presents a digital implementation of delta modulation Technique for Active Power Filters. Delta modulated scheme is to control the harmonic-compensating current indirectly by adjusting the capacitor voltage to be sinusoidal. The overall control system has two feedback loops. One is the outer propotional feedback for loop regulating the dc current of active filters and the other is the inner feedback loop for maintaining the ac current waveform to be sinusoidal, and have zero power factor angle(i.e. unity power factor). The characteristics of the proposed is investigated by digital simulation using ACSL and experimental results are obtained by TMS370C756 Single-Chip Microprocessor relative to analog delta modulation technique.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.6 no.3
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• pp.148-151
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• 2013

A new direction of arrival estimation method using effects of model errors and sensitivity analysis is proposed. Since a desired signal is obtained after interference rejection through correction effects of model error, the effect of channel interference on the estimation is significantly reduced. Through simulation, we show that the proposed method offers significantly improved estimation resolution and accuracy relative to existing method.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.185-190
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• 2007

This article describes a development CDMA LBS in order to apply to "Control System of Underground Infrastructure Fire Accident" which one of U-City Projects of Seoul City. Our goal guides taking shelter of the sufferer it will not be able to use a GPS when the fire occurs from subway station. There are Location measurement methods which measures the AOA(Angle of Arrival) of the signal which it sends with the MS(Mobile station) from the BS(Base station), an electronic delivery time (TOA:Time of Arrival) and the relative difference of electronic arrival time from Base stations (TDOA:Time Difference of Arrival). This time the error due to a multiplex course error and near-far problem and NLOS(Non Line of Sight). We are planning to construct the Test Bed which is an error below 1 meter.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.9 no.3
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• pp.113-119
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• 1984

In the scattering of a monochromatic plane wave from a dielectric column oscillating sinusoidally prependicular to its axis, one could assume that the boundary moves with a uniform velocity equal to its instantaneous oscilaating velocity. The scattered fields are abtained according to the postulates of special relativitiy and extended for the osdillating period. The angle distribution of average scattering radiation, the average of total scattering cross sections and radar cross sections for a period are illustrated as the function of the relative maximum oscillating velocity and the incident angles of plane waves.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.1114-1119
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• 1995

This paper presents the development of estimation model and control method based on the new computer vision. This proposed control method is accomplished using a sequential estimation scheme that permits placement of the rigid body in each of the two-dimensional image planes of monitoring cameras. Estimation model with six parameters is developed based on a model that generalizes known 4-axis scara robot kinematics to accommodate unknown relative camera position and orientation, etc. Based on the estimated parameters,depending on each camers the joint angle of robot is estimated by the iteration method. The method is tested experimentally in two ways, the estimation model test and a three-dimensional rigid body placement task. Three results show that control scheme used is precise and robust. This feature can open the door to a range of application of multi-axis robot such as assembly and welding.