• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.7
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• pp.25-31
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• 1998

Modal transmission-line is utilized to analyze the power coupling of optical directional coupler composed by two parallel guiding slabs. By defining a coupling efficiency .eta. amenable to rigorous supermodes and boundary conditions of modal functions, we evaluate the power transfer for TE mode of gainy coupler. The results reveal that optimized power exchange occurs at a novel wavelength .lambda.$_{op}$ , which is generally different from minimum gap .lambda.$_{min}$ between rigorous modes and phase-matching condition .lambda.$_{ph}$ .

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.9
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• pp.1231-1238
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• 1995

In on-line character recognition, to segment input character is important. This paper proposes an internal character segmentation algorithm. The internal segmentation algorithm produces candidate words by considering possible combinations of Korean alphabets. In this process, we make use of projections of strokes onto the horizontal axis to remove ambiguities among candidate words. As a result of experiments, the internal segmentation algorithm shows better performance than external segmentation algorithm as the gap between sample characters becomes smaller.

• 연구논문집
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• s.24
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• pp.49-61
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• 1994

In this paper, the experimental unit of the cross inductive radio line and two linear induction motors driven by IGBT inverter for train control was made. In actual condition, the track has straight line, but so as to be able to achieve in small space, the unit prepared was shaped into two circular plates. Then by detecting inductive signal, the position data could be obtained. Also the equipment representing speed and thrust of LIM and train position by means of the experimantal unit could be composed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.168-171
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• 2003

Generally RF AGC (Roll Force Automatic Gauge Control) controls the roll gap using the variation of rolling force caused by the roll eccentricity and the entry thickness of material, but RE AGC takes the bad effect of the roll eccentricity. The Feed-forward (FF) AGC method, which controls the next stand roll gap by the estimation of the thickness variation due to skid mark is needed to supplement the shortage of RF AGC. In this paper, an adaptive filtering method which takes account of the kind of material, the final objective thickness and the rolling speed is proposed to predict skid mark thickness variation. In addition, an improved estimation method of control point using a speedometer and looper angle is suggested. Via on line test, the performance improvement of the suggested FF AGC method is verified.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.6
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• pp.897-903
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• 2002

In this paper, a modified feeding structure for microstrip patch antenna is suggested for improving the performances. The proposed antenna has a gap between the transmission line and the recessed part of the radiating patch which makes a capacitive coupling. It shows higher 511(-l4dB) and lower cross polarization level(-2OdB) compare with the conventional inset ftd patch antenna while having a similar characteristics in another evaluating items. Experimental results are examined and considered to apply to the S-Band application, and the effectiveness has been confirmed by FDTD simulation and measurement simultaneously.

• Proceedings of the KWS Conference
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• 2005.11a
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• pp.138-140
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• 2005

Plasma arc welding(PAW) technology is a proven process that has already been adopted by other industrial fields and recently has been considered to join the tank structure of LNG carrier. The purpose of this study is to introduce PAW process for the root welding of stainless steel pipes instead of TIG welding. There are distinctive features of the PAW compared to TIG welding; higher energy density that can increase welding speed by more than twofold, and longer arc length that can be controlled to trace seam line easily because of allowable gap between workpiece and torch. However, PAW process is also very sensitive to the root gap and misalignment due to the characteristics of long and narrow arc shape. So, we have done various experiments to establish the allowable fit-up condition by changing welding parameters including arc length, with or without filler metal, groove shape, and obtained satisfactory result.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.2
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• pp.45-52
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• 2012

Enrichment planting is commonly used for increasing the density of tree species in secondary forests and one of forest rehabilitation programs in Lao PDR. This study aimed to determine the performance of five native species in enrichment planting using different canopy opening treatments, and to examine the suitable species and silviculture techniques applicable to a logged-over forest in Lao PDR. Results of the study showed that only crown height had significant difference among species and planting treatments. The survival rate and crown diameter were significantly different by species, but not by planting treatments. However, root collar diameter (RCD) and height of seedlings showed significant differences among planting treatments. Among the study species, Hopea odorata and Dalbergia cochinchinensis showed significantly higher survival rate and height growth, indicating their suitability in enrichment planting for rehabilitation of forest in Lao PDR. The results also suggested that 2 m width line planting stimulated RCD growth, but wider line planting, such as gap planting, promoted height growth of seedlings.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.1
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• pp.52-57
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• 2005

In the foe of global competition, the requirements for the continuously increasing productivity, flexibility and quality(dimensional accuracy, mechanical properties and surface properties) have imposed a mai or change on steel manufacturing industries. Indeed, one of the keys to achieve this goal is the automation of the steel-making process using AI(Artificial Intelligence) techniques. The automation of hot rolling process requires the developments of several mathematical models for simulation and quantitative description of the industrial operations involved. In this paper, an on-line training neural network for both long-term teaming and short-term teaming was developed in order to improve the prediction of rolling force in hot rolling mill. This analysis shows that the predicted rolling force is very closed to the actual rolling force, and the thickness error of the strip is considerably reduced.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1642-1644
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• 1997

The simulation study of lightning faults reducing effects by the installation of surge arresters on the 154 kV transmission line is stated here. For the purpose of detailed simulation of arcing horn, a flashover model with dynamic characteristics of arcing horn gap was represented as a non-linear inductance which is controlled by EMTP/TACS(Electromagnetic Transient Program/fransient Analysis of Control Systems) switches. The back flashover inducing current was increased from 50 kA to 88 kA by the installation of surge arresters on the transmission line which has one ground wire and 20 ohms of tower footing resistances. The great advantage of surge arrester installation on one circuit of the double circuit transmission line is to prevent the simultaneous back flashover up to 190 kA.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.142-144
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• 2009

We demonstrated narrow and good aspect-ratio inkjet-printed silver lines with multi-time over-printing methods. By using this strategy, narrow silver lines were obtained with 200 nm thickness and their width and gap between printed lines of uniform narrow silver lines were 30 ${\mu}m$ and 17 ${\mu}m$, respectively. It also had good conductivity, sheet resistacne of 0.36 ${\Omega}/{\square}$ and specific resistance of $8{\mu}{\Omega}{\cdot}cm$. In current stress test, narrow silver line with 30 ${\mu}m$ width was able to a current flow up to 50 mA (2.1A/$cm^2$). Using surface treatment on poly-arylate substrate with $UVO_3$, we obtained clean-edge narrow line without any edge waviness.