• 제어로봇시스템학회논문지
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• 제13권8호
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• pp.817-823
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• 2007

GPS and INS can be integrated in 3 ways of loose, tight, and ultra-tight configuration. This paper investigates the performance of GPS/INS ultra-tightly integrated system when unscented Kalman filter(UKF) is adopted as well as extended Kalman filter(EKF). Covariance analysis is performed using UFK and EKF for tightly coupled and ultra-tightly coupled systems. Various trajectories such as straight, circle, S-shape, spiral are considered for the simulations of covariance analysis.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.82-85
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• 2002

This paper proposes a new position detection method for train speed control using the PDOA(Phase Difference of Arrival). This method aims to apply to AGT(Automated Guide way Transit) systems, operated with driverless. So it is absolutely required to range, calculate and decide a train position precisely. This system consists of VRS (Vehicle Radio Set) and WRS(Wayside Radio Set). The VRS transmits a wireless signal to the WRS, the controller calculate a straight line with the PDOA. Next step calculate an exact position using track DB. This paper includes the concept, configuration, analysis and results of this method.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 추계학술대회(제116회) 및 13회 Workshop 제3회 한ㆍ일 치과보존학회 공동학술대회 초록집
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• pp.553-553
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• 2001

The purpose of this study is to identificate root canal system including ideal access placement, root curvature, canal configuration, incidence of isthmus in mandibular incisors for success of endodontic treatment. 200 mandibular incisors were selected. The ideal access placement was determimed as follows. The teeth were radiographed from mesiodistal and buccolingual views using intraoral dental film. The image was divided into coronal, middle and apical third using the proximal film. Straight line access was determined by measuring the faciolingual canal width and placing points at midway point between the buccal and lingual wall at the junction of the middle and apical third and at the juntion of coronal and middle third of the root canal.(omitted)

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 추계학술대회(제116회) 및 13회 Workshop 제3회 한ㆍ일 치과보존학회 공동학술대회 초록집
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• pp.562.2-562
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• 2001

The purpose of this study is to identificate root canal system including ideal access placement, root curvature, canal configuration, incidence of isthmus in mandibular incisors for success of endodontic treatment. 200 mandibular incisors were selected. The ideal access placement was determined as follows. The teeth were radiographed from mesiodistal and buccolingual views using intraoral dental film. The image was divided into coronal, middle and apical third using the proximal film. Straight line access was determined by measuring the faciolingual canal width and placing points at midway point between the buccal and lingual wall at the junction of the middle and apical third and at the juntion of coronal and middle third of the root canal.(omitted)

• 에너지공학
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• 제2권1호
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• pp.38-44
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• 1993

Electromagnetic seawater thrusters may be classified into four general categories : internal duct dc, external field dc, internal peristaltic ac, and external peristaltic ac. Internal duct dc thrusters offer the advantages of low magnetic field leakage, simple construction, and potentially high reliability. The most efficient internal duct configuration consists of converging inlet nozzle and a straight discharge duct. Ideal efficiency calculations based on the one-dimensional Bernoulli equation show that thrusters should be designed with large cross-sectional areas and operate at low discharge velocities. In practice, this may be accomplished by using multiple thruster ducts. Conductivity enhancement, high magnetic fields, and long electrodes will also improve efficiency.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2658-2663
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• 2008

In the present study, we designed a microfluidic flatform that generates monodisperse droplets with diameters ranging from hundreds of nanometers to several micrometers. To generate fine droplets, T-junction and flow-focusing geometry are integrated into the microfluidic channel. Relatively large aqueous droplets are generated at the upstream T-junction and transported toward the flow-focusing geometry, where each droplet is broken up into the targeted size by the action of viscous stresses. Because the droplet prior to rupture blocks the straight channel that leads to the flow-focusing geometry, it moves very slowly by the pressure difference applied between the advancing and receding regions of the moving droplet. This configuration enables very low flow rate of inner fluid and higher flow rate ratio between inner and outer fluids at the flow-focusing region. It is shown that the present microfluidic device can generate droplets with diameters about 1 micrometer size and standard deviation less than 3%.

• Restorative Dentistry and Endodontics
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• 제7권1호
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• pp.53-57
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• 1981

A total of 130 extracted human maxillary second molars were used to study the configuration of the floor of the pulp chamber. The specimens were ground and the pulp chamber was examined with a magnifier and explored with sharp explorer. The study showed the shape of the pulp chamber, number of root canals, and the type of canal orifice. The results were as follows; 1. In so far as observing the shape of the pulp chamber of the teeth, 16.9% of the teeth were quadrilateral, 70.0% were triangle and 13.1% were ovoid shape. 2. 13.1% of the specimens have 4 root canal orifices. 73.9% have 3 root canal orifices, 11.5% have 2 root canal orifices and 1.5% have single orifice. 3. 13.1% of the specimens have 2 mesio-buccal canal orifices and among the teeth those have 3 canals, 20.8% show 'Y' shape, 29.1% show straight line and 23.8% show obtuse triangle shape.

• 한국멀티미디어학회논문지
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• 제19권8호
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• pp.1329-1336
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• 2016

This paper develops a 360 degree video system using multiple off-the-shelf webcams and a set of embedded boards. Existing 360 degree cameras have shortcomings that they do not support real-time video generation since recorded videos should be copied to computers or smartphones which then provide stitching. Another shortcoming is that wide FoV(Field of View) cameras are not able to provide sufficiently high resolution. Moreover, resulting images are visually distorted bending straight lines. By employing an array of 65 degree FoV webcams, we were able to generate videos on the spot and achieve over 6K resolution with much less distortion. We describe the configuration and algorithms of the proposed system. The performance evaluation results of our early stage prototype system are presented.

• 한국항해학회지
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• 제10권2호
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• pp.97-114
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• 1986

Ship's maneuverability is very important factor in safe ship handling and economical ship operation. Steering characteristics are consisted of course stability and maneuverability. Today in many advanced ship-building countries, they study ship's course stability, using model ship tests, such as straight line tests, rotating arm tests and Planar Motion Mechanism (PMM) etc., in tow in tanks. It is the purpose of this paper to provide ship's handlers with better understanding of steering characteristics and to help them in safe controlling and manevering . In this paper, the author simulated response of various vessels, running straight course with constant speed, and they are disturbed by small external disturbance of one degree yaw angle with no angular velocity . The author used the hydrodynamic derivtives resulted at tests of Davidson's laboratory in Stevens Institute of Technology, New Jersey, U.S.A. Course stability was evaluated and analyzed in various respects, such as block coefficient, ratio of ship's length to beam, draft and rudder area ratio etc. The obtained results are as follows : (1) The ship's course stability is affected by magnitude of block coefficient greatly. In case that the block coefficient is more than 0.7, the deviation varies at nearly same rate but the requistite time to reach the steady course is different. (2) The ship's course stability is affected by magnitude of L/B. When the dimensionless time reaches about 3, the deviation and requisite time to reach the steady course are influenced nearly same. After the dimensionless time is about 3, they change on invariable ratio. (3) The effect to course stability by L/T and RA' can be neglected. (4) The reason why thy VLCC and container feeder vessel are unstable on their course is that their block coefficient is generally more than 0.8 and the ratio of ship's length to beam is about 6.0.

• 한국주거학회논문집
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• 제26권2호
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• pp.47-56
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• 2015

Traditional Hanok in modern society, depending on the improvement of economic and cultural level is evolving as a modern Hanok. An ideal of traditional Hanok and convenience of a modern housing does not match rather conflicting. This study deals the transformation of a new Hanok, which are build in Jeollanam-do province sponsored by local government from 2007. The subjects was selected 34 cases from Sunchon and Damyang which are build sponsored by Jeollanam-do local government from 2009 to 2011. The report is a design drawing of a Hanok, architectural survey of the Hanok research using questionnaires and interviews with the client or a resident, was confirmed by a visit to check and verify for each Hanok houses. Outside shape classification of Hanok were classified as straight, L type, and the interior space was analyzed by focusing on the living room, dining room, kitchen configuration consisting of housing space in public life. This study and the type of Hanok round out the framework from the perspective of residence' demands and realize new Hanok investigated and the evolution of the process is meaningful to find a Hanok.