• Digital Contents
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• no.1 s.8
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• pp.61-63
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• 1994

• Korean Journal of Remote Sensing
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• v.13 no.2
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• pp.133-150
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• 1997

The purpose of this paper is to develop an algorithm of classification and interpretation of seafloor based on side scan sonar data. The algorithm consists of mosaicking of sonar data using navigation data, correction and compensation of the acouctic amplitude data considering the charateristics of the side scan sonar system, and segmentation of the seafloor using digital image processing techniques. The correction and compensation process is essential because there is usually difference in acoustic amplitudes from the same distance of the port-side and the starboard-side and the amplitudes become attenuated as the distance is increasing. In this paper, proposed is an algorithm of compensating the side scan sonar data, and its result is compared with the mosaicking result without any compensation. The algorithm considers the amplitude characteristics according to the tow-fish's depth as well as the attenuation trend of the side scan sonar along the beam positions. This paper also proposes an image segmentation algorithm based on the texture, where the criterion is the maximum occurence related with gray level. The preliminary experiment has been carried out with the side scan sonar data and its result is demonstrated.

• Journal of the Korean Geotechnical Society
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• v.21 no.9
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• pp.5-12
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• 2005

SPT hammer energy and its delivery are hon to influence the N value. The SPT hammer energy is classified into theoretical energy, velocity energy, rod energy and dynamic efficiency. In this study, the rod energy and the velocity energy are measured directly by PDA and Digital Line-Scan Camera which are most widely used type of SPT apparatus in Korea. The Dynamic efficiency is calculated through measured data. As the results of this study, the averages of rod energy ratio of donut, safety and automatic hammer are measured at 49.57, 61.60, and at $87.04\%$ by FV method. The averages of hammer velocity of donut, safety and automatic hammer are measured at $3.177{\pm}0.872$, $3.385{\pm}0.681$, and at $3.651{\pm}0.550$ m/s by Digital Line-Scan Camera, with the dynamic efficiencies at 0.732, 0.801, and 0.973 respectively.

• Journal of Biomedical Engineering Research
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• v.21 no.4
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• pp.419-431
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• 2000

In this paper, a new beamforming technique is proposed, which can completely eliminate all the artifacts caused by digital scan converter. In the proposed method, named display-pixel-based focusing(DPBF) by the authors, ultrasound waves are focused directly at the display pixels instead of sampling points on the polar coordinate. Consequently. the DPBF system does not require the digital scan converter. To verify the proposed method, we modified a commercial scanner and performed experiments with a 3.5 MHz convex array and a 7.5 MHz linear array. We also defined and measured ICRA/B(Image Coarseness Ratio) to compare the image quality quantitatively. The experimental results with in vivo and in vitro data show that the proposed method improves the ICRA/B considerably, resulting in much smoother and finer images.

• The Journal of Korean Academy of Prosthodontics
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• v.62 no.1
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• pp.82-94
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• 2024

This is a case report of complete mouth rehabilitation in a patient with generalized attrition and loss of posterior support. After analyzing the condition of the temporomandibular joint, multiple implants were placed to restore collapsed occlusion. Fixture/abutment level intraoral scanning was done instead of using conventional impression materials which entail multiple bite registration for cross-mounting. A 'jaw motion tracking'device, 'digital face-bow transfer', and 'double scan technique' which enables duplicating temporary restoration to definitive restoration were used to fabricate definitive prostheses. By using various digital techniques, complete mouth rehabilitation was done with minimal chair time in a patient with unstable occlusion.

• The Journal of the Korean dental association
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• v.58 no.8
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• pp.505-512
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• 2020

With the fourth industrial revolution, digitization is accelerating in all healthcare areas. In the field of dentistry, active discussions on digital dental technologies are ongoing, with increasing interest from clinicians daily. Thus far, accuracy and efficiency have primarily been emphasized in digital dentistry, and interest in occlusion has been relatively low. This is because digital dentistry has been predominantly used to restore small numbers of teeth rather than extensive prosthetic reconstruction. However, in the future, most dental treatments will undergo a digital transformation that will require the application of digital technology to more extensive prosthetic rehabilitation, for which discussion of occlusion is essential. In extensive prosthetic reconstruction, occlusion and articulation involve determining the position of the dental arch in relation to the reference plane of the skull or the long axis of the face and the position of the transverse horizontal axis. It also includes determining an occlusal surface with a shape that allows the mandible to move in an eccentric path and masticate most efficiently without any occlusal interference. To better understand how digitization will impact dentistry, this review article summarizes and discusses occlusion and articulation using digital dental technologies. This discussion is divided into several aspects, including facial scan, virtual articulation, augmented reality, and virtual reality.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.5
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• pp.749-758
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• 1995

There are many testable design techniques, among which Scan path and BIST techniques are mainly used. In this paper, the increase of design effectiveness is discussed, when these techniques are applied to the practical implementation of chips. The following techniques are presented : 1) Blocks are commonly used to reduce test time without hardware increase, 2) MUX is used to implement the shortest Scan path, 3) Scan register is used which controls and/or observes several blocks to avoid the increase of hardware.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.1
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• pp.48-53
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• 2000

In this paper, we develop a TMS320C31 (60MHz) digital signal processor (DSP) board to synthesize gradient waveforms for Spiral Scan Imaging (SSI), which is one of the ultra fast magnetic resonance imaging (MRI) methods widely used. In SSI, accurate gradient waveforms are very essential to high quality magnetic resonance images. For this purpose, sampling rate for synthesizing the gradient waveforms is set twice as high as the data sampling rate. With the developed DSP boards accurate gradient waveforms are obtained. Ultra fast spiral scan imaging with the developed with the developed DSP board is currently under development.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1250-1254
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• 1992

This paper describes the designed and fabricated thermal imaging system with the SPRITE(Signal PRocessing in The Element) detector, operating in the 3-12 micron band. This system consists of an afocal telescope, a scan unit containing the SPRITE detector, an electronic processor unit and a cooler. The optical scan system utilizing rotating polygon and oscillating mirror, is 2-dimensional serial/parallel scan type using five elements of the detector. And the electronic processor unit performs digital scan conversion to reform the parallel data stream into serial analog data compatable with conventional RS-170 video. The scan field of view is 40 ${\times}$ 26.7 and the MRTD(Minium Resolvable Temperature Difference) is 0.6 K at 7.5 cycles/mm. The acquired thermal image indicates that this system has a satisfactory performance.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.9
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• pp.1161-1166
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• 1999

Delay testing has become highlighted in the field of digital circuits as the speed and the density of the circuits improve greatly. However, delay faults in sequential circuits cannot be detected easily due to the existence of state registers. To overcome this difficulty a new scan filp-flop is devised which can be used for both stuck-at testing and delay testing. In addition, the new scan flip-flop can be applied to both the existing functional justification method and the newly-developed reverse functional justification method which uses scan flip-flops as storing the second test patterns rather than the first test patterns. Experimental results on ISCAS 89 benchmark circuits show that the number of testable paths can be increased by about 10% on the average.