• Journal of the Korean earth science society
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• v.33 no.5
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• pp.395-400
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• 2012

One of the main problems concerning the shallow seismic survey is how to generate high frequency signals with large amplitudes using small seismic sources. If one could focus the seismic energy in the direction of the survey line, it will be much helpful in identifying the first break. In this research, we have used hammer as an impulsive source and compared the signal powers generated by different shapes of the hammer plates: circular, square, and rectangular. The experiment was conducted by calculating the power spectral density function to compare the frequency spectrum and signal power. In the direction perpendicular to the long side of the rectangular plate, the largest seismic energy with the highest frequency was achieved even with the same weights of hammer plates. Our conclusion is that it is more efficient to use a rectangular plate than a circular (or square) one when conducting a 2-D shallow seismic survey.

• The Journal of the Korean dental association
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• v.51 no.11
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• pp.586-594
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• 2013

The critical factors affecting the esthetics of anterior implants can be summarized as following: 1) Correct positioning of implant fixture 2) Enough amount of alveolar bone 3) Optimum volume of soft tissue. The position of implant is probably the most important factor in obtaining esthetic treatment outcome. The 3-dimensional orientation of implant is determined by the position on the alveolar ridge and its direction. Clinicians often try to mimic natural teeth when fabricating restorations. During the course of esthetic diagnosis and treatment, however, one should not forget to consider the correlation between facial pattern, lips, gingiva, alveolar ridge, as well as remaining dentition. Since anterior region is biologically unfavorable when compared with posterior region, one minor discrepancy in positioning of implant can cause esthetically undesirable treatment outcome. If one understands the biological and prosthetic meaning of implant's 3-dimensional position, he or she can achieve superior esthetic outcome in anterior region.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.946-948
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• 1996

In this paper, we consider a 2-dimensional pursuit-evasion game between a maneuvering target and a coasting missile using qualitative game theory. The optimal evasion algorithm of the target and the optimal guidance algorithm of the missile are determined and the barrier trajectories of this game are obtained through computer simulation. The optimal strategy of the missile and target is to turn toward the final line of sight direction using maximum input and maintain its direction. The capture set of the missile can be obtained by backward integration from the BUP.

• Educational Technology International
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• v.7 no.2
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• pp.23-44
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• 2006

As the educational paradigm has shifted from the traditional knowledge oriented instruction learning to the knowledge product oriented instructional learning, the development of student's creativity becomes one of the most important educational goals, because the ability that can produce the knowledge creatively is required in the digital information knowledge based society. The purpose of this study is to make a basic direction and strategy for the instructional design to develop an on and off line blended instructional design which will help a learning community to be a more collaborative and creative learning community. This research has investigated the concept and the characteristics of collaborative creativity and creative problem solving as the theoretical basis of the design. After that, on the basis of the theories connected with the collaborative creativity theory, the direction and the strategies for the development of collaborative creativity was designed. The design was applied into the real learning community and finally proved the effectiveness of the learning model for the development of the collaborative creativity by the quantitative evaluation.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1190-1195
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• 2003

In this paper, it is shown how a robot with n passive trailers can be controlled in backward direction. When driving backward direction, a kinematic model of the system is represented highly nonlinear equations. The problem is formulated as a trajectory following problem, rather than control of independent generalized coordinates. Also, the state and input saturation problems are formulated as a trajectory generation problem. The trajectory is traced by a rear hinge point of the last trailer, and reference trajectories include line segments, circular shapes and rectangular turns. Experimental verifications were carried out with the PSR-2(public service robot $2^{nd}$ version) with three passive trailers. Experimental result showed that the backward motion control can be successfully carried out using the proposed control scheme.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.4
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• pp.539-544
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• 2009

The constraint effect $A_2$ has to be evaluated within plastic region near crack tip front using opening displacement. Plastic boundary and stress or strain conditions in the vicinity of the crack tip using recrystallization heat treatment was represented. It was found that the plastic deformation boundary by recrystallization heat treatment method was the true strain of ${\epsilon}t$ = 0.05mm/mm. With the estimation of constraint effects $A_2$, the region of proper displacement measurement point near crack tip was between 0mm and 1mm distance toward direction of crack propagation, and was between 1mm to 3mm distance toward direction of load line.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.1
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• pp.43-48
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• 2009

The fatigue crack growth behavior of high strength X80 pipeline steel was investigated with compact tension specimens that crack growth directions were aligned either parallel or normal to the rolling direction of the pipeline. Also, the fatigue crack growth rates for welded joint of X80 pipeline steel were investigated with compact tension specimens that crack growth directions were aligned either parallel or normal to the welding line. The experimental results indicated the fatigue crack growth behavior was markedly different in three zones, weld metal, heat affected zone and base metal of welded joints. There was a trend toward increment in the fatigue life of weld metal and heat affected zone as compared with the X80 pipeline steel.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2413-2425
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• 2008

Until now, Many papers were written by graduate school students and consultents about railway station as main consideration. But there is no paper about specific private-invested station development. So in this paper, Just consider limiting Dong-Incheon private-invested station on a noncompetitive point of view that also constructed as a part of railway station development. This paper will be referenced of private-invested station management and direction of development in Korail railway station development. Private-invested station development is actively drived to now after Seoul private-invested station in 1989 as Korail's first induced private capital. Dong-Incheon private-invested station also built in 1989 and operated to now, but it can't keep up with current market and can't meet changeable commercial business. So in this paper, comparing Dong-Incheon private-invested station with one of the successful private-invested stations which is youngdengpo private-invested station and seeking the improvement direction of Dong-Incheon private-invested station as considering Dong-Incheon private-invested station's floating, traffic system, walking line, the range of station, the development type, facilities, and other nation's developing cases.

• Journal of Information Technology Services
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• v.7 no.4
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• pp.61-86
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• 2008

Korea 5MBA(Small and Medium Business Administration) is operating SMEs Policy Information System called SPi-1357 as a part of electronic government business, G4B. SPi-1357 system is offering tailor made policy information to a nation through on-off line system. In this paper, I provide the offering status of policy information, the status of SPi-1357 system, political results of SPi-1357 system, comparison with other country's policy information system, and the development direction of SPi-1357 system. Until now, most Policy Information Systems documents have focused on policy maker but the focus of this paper is functionally oriented SMEs.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.12
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• pp.2300-2307
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• 2008

This study receives the noise transmitted in a constant audio frequency range through a microphone array in which the noise(like grease in a pan) occurs on the power supply line due to the troublesome partial discharge(arc). Then by going through a series of signal processing of removing noise, this study measures the distance and direction up to the noise caused by the troublesome partial discharge(arc) and monitors the result by displaying in the analog and digital method. After these, it determines the state of each size and judges the distance and direction of problematic part. When the signal sound transmitted by the signal source of bad insulator is received on each microphone, the signal comes only in the frequency range of 20 kHz by passing through the circuit of amplification and 6th low pass filter. Then, this signal is entered in a digital value of digital signal processing(TMS320F2812) through the 16-bit A/D conversion. By doing so, the sound distance, direction and coordinate of bad insulator can be detected by realizing the correlation method of detecting the arriving time difference occurring on each microphone and the algorithm of detecting maximum time difference.