• KIPS Transactions on Software and Data Engineering
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• v.6 no.4
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• pp.211-216
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• 2017

This paper proposes image processing techniques that improve usability and performance in a diagnostic system of the contrast-enhanced ultrasonography. For a methodology for visualizing diagnostic parameter data in an ultrasonic medical image, an expression of transition time data with successive pixel values and a method of generating a lesion diagnostic parameter image with four categorized values are presented. We also introduce a MRF-based image enhancement technique to eliminate noises from generated parametric images. Such parametric image generation technique can overcome the difficulty of discriminating dynamic change in patterns in the ultrasonography. The technique clarifies the contour of the region in the original image and facilitates visual determination of the characteristics of the lesion through four colors. With regard to this MRF-based image enhancement, we define the energy function of consecutive pixel values and develop a technique to optimize it, and the usability of the proposed theory is examined through experiments with medical images.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.1
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• pp.63-68
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• 2013

Some essential components in nuclear power plants are periodically inspected using non-destructive examinations, for example ultrasonic, eddy current and radiographic examinations, in order to determine their integrity. These components include nuclear power plant items such as vessels, containments, piping systems, pumps, valves, tubes and core support structure. Steam generator tubes have an important safety role because they constitute one of the primary barriers between the radioactive and non-radioactive sides of the nuclear power plant. There is potential that if a tube bursts while a plant is operating, radioactivity from the primary coolant system could escape directly to the atmosphere. Therefore, in-service inspections are critical in maintaining steam generator tube integrity. In general, the eddy current testing is widely used for the inspection of steam generator tubes due to its high inspection speed and flaw detectability on non-magnetic tubes. However, it is not easy to analyze correctly eddy current signals because they are influenced by many factors. Therefore, the performance of eddy current data analysts for steam generator tubing should be demonstrated comprehensively. In Korea, the performance of steam generator tubing analysts has been demonstrated using the Qualified Data Analyst program. This paper describes the performance demonstration program for steam generator tubing analysts and its implementation results in Korea. The pass rate of domestic analysts for this program was 71.4%.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.6
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• pp.525-532
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• 2017

The development of an inkjet-based manufacturing machine for the production of next-generation displays using organic and quantum-dot light emitting diodes at a low cost has been conducted. To employ inkjet printing in production lines of displays, the development of a high-speed inkjet-monitoring device to verify the reliable droplet jetting status from multiple nozzles is required. In this study, an inkjet monitoring device using a rotatable mirror with rotary and linear ultrasonic motors is developed in place of a conventional, linear reciprocating, motion-based inkjet monitoring device. Its performance is also demonstrated. The measurements of circular patterns with diameters of $10{\mu}m$, $30{\mu}m$, and $50{\mu}m$ are performed with the accuracies of $0.5{\pm}1.0{\mu}m$, $-1.2{\pm}0.3{\mu}m$, and $0.2{\pm}0.5{\mu}m$, respectively, within 17 sec. By optimizing the control program, the takt time can be reduced to as short as 8.6 sec.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.1198-1202
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• 2004

초음파를 이용한 측정은 하천의 반대편에 흐름방향에 경사지게 초음파를 발사하여 다시 반사되어 오는 시간차를 기록함으로써 주어진 길이에서 유속을 연속적으로 측정하는 것이다. 하류로 내려가는 음파는 음향 측선(acoustic path)과 평행한 유속 성분 때문에 상류로 올라가는 음파보다 빠른 속도를 가진다. 탄천 및 괴산댐에 초음파 유량 측정시스템을 시험 설치하고 운영 결과를 검토하였다. 시험적용결과 연속적인 유량자료 획득이 가능하였으며, 기존 유속면적법 대비 $4.21\%$의 상대오차를 지니고 있어 기존 방법과 비교적 일치하는 측정결과를 나타냈다. 또한 지표유속(Index Velocity)를 활용한 단일회선 유량산정법을 검토한 결과, 다회선에 의해 운영한 결과와 평균 $2.9\%$의 상대오차를 지니고 있었다. 이 방법은 조석구간 및 배수영향을 받는 구간에서 작은 비용으로 연속유량자료를 획득할 수 있는 방법으로 판단된다. 시험적용 결과 개선해야 할 사항으로는 안정적인 자료 획득을 위한 초음파 변환기의 개선, 자료의 필터링 기술의 정밀화, 그리고 유량산정 방법에서 정확도 향상 기술 개발 등이 도출되었다. 초음파 유량 측정시스템은 자료의 연속성을 확보할 수 있는 점에서 매우 중요한 의미를 지니고 있다. 지금까지의 연속 유량 산출법은 연속적인 수위를 측정하고 각 수위에 따른 유량 측정 후 수위-유량관계를 통하여 연속적인 유량을 산출하였다. 그러나 초음파 유량 측정 시스템은 직접 유속과 수위를 측정하여 연속유량이 산출되기 때문에 연속유량 산출에 비교적 간편하다고 할 수 있다. 또한 정확도 면에서 기존 유량 측정법인 유속-면적법의 불확실도 $5\%\~10\%$에 비교하여 $5\%$ 내외의 정확도 수준을 지니고 있어 정확도 향상을 기대할 수 있다. 경제적인 측면에서도 매년 측정사업에 소요되는 비용과 비교하였을 때 장기적으로는 경제적인 방법이 될 수 있다.

• Analytical Science and Technology
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• v.15 no.3
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• pp.300-316
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• 2002

The extraction methods of PBBs from environmental samples by soxhlet extraction for solid phase and liquid-liquid extraction for liquid phase were compared. After extraction, silicagel and florisil as column clean up methods were used for the comparison of cleanup efficiency with different solvent system. Also, the analytical instruments were used GC/MSD. The 22 kinds of PBBs standards were used to establish the analytical methods to perform the experiments of recoveries and detection limits in water and soil. The detection limits of PBBs represented 5~10 ng/L for water and 0.5~3.5 ng/g for soil samples, respectively. The recoveries of water samples represented 96~107% in n-hexane, dichloromethane and toluene for water, and 60~80% in combined solvent with n-hexane and acetone. The recoveries of soil sample were surveyed 67~97% in soxhlet extraction and 64~76% in ultrasonic extraction with selected solvents.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.5
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• pp.696-705
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• 2007

Statement of problem: In the Protar articulator, the models are almost parallel with the Camper's plane. The ultrasonic-based ARCUSdigma system is basis for the determination of dynamic function parameters with so-called "articulator related registration". Purpose: The purpose of this study was to compare the sagittal condylar guidance angles found by use of the wax protrusive records in a semi-adjustable articulator(KaVo Protar 7) with those found by use of the Axiograph (ARCUSdigma). 83 volunteers with intact dentition participated in this study after obtainment of informed consent. Material and method: The sagittal condylar guidance angles were measured and estimated statistically by semi-articulator and Axiograph. All the readings were in degrees. No control was used in this project. To test whether there was a significant difference between the 2 independent samples, paired t-test and Kruskal-Wallis test were carried out(p=.05). Results: 1. The mean results for the wax protrusive records were as follow: right side (32.65 degrees, SD 16.48); left side (33.27 degrees, SD 17.49). 2. The mean results for the Axiograph were as follow: right side (32.26 degrees, SD 7.00); left side (33.07 degrees, SD 7.58). 3. There was no statistical difference on the wax protrusive records and Axiograph(p>0.05). Conclusion: Both methods of wax protrusive records and Axiograph are clinically acceptable for measuring the sagittal condylar guidance angles in semi-adjustable articulators.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.8
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• pp.483-488
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• 2016

Ultrasound imaging by using piezoelectric materials, such as lead zirconium titanate (PZT) has been one of the most preferred modes of imaging in the medical field due to its simple, low cost and non-ionizing radiation in comparison to other imaging techniques. Recently, the market demand for portable ultrasound is becoming larger with applications in developing countries, disaster area, military, and emergency purposes. However, most of ultrasound probes used is bulky and high power consumable, so unsuitable for such applications. In this study, the 3 layered ceramic specimen consisted of 128 pitches of $420{\mu}m$ in width and $450{\mu}m$ in thickness were prepared by using the Ti-rich PZT compositions co-fired at $1,050^{\circ}C$. Their electrical and ultrasound pulse-echo properties were investigated and compared to the single layer specimen. The 3 layered ultrasound probe showed 1.584 V of Vp-p, which is 3.2 times higher than single layered one, implying that it would allow effectively such a portable ultrasound probe system. The result were discussed in terms of higher capacitance, lower impedance and higher dielectric coefficient of the 3 layered ultrasound probe.

• Restorative Dentistry and Endodontics
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• v.26 no.5
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• pp.379-386
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• 2001

This study was performed to evaluate the sealing ability of various retrograde filling materials by using bacterial penetration and dye penetration test. One hundred and forty extracted human teeth with single, straight canals and mature apiece were collected and used for this study. All canals were instrumented using an engine driven Ni-Ti file (ProFile). After removing 3mm from the apex of tooth, a standardized 3mm root end cavity was prepared using an ultrasonic instrument. The 70 teeth were randomly divided into 7 groups : 6 groups for retrograde filling using Super-EBA, ZOE, Chelon-Silver, IRM, ZPC and amalgam. The 7th group was used as a negative control. Nail varnish was applied to all external root surfaces to the level of the reseated root ends to prevent lateral microleakages. The specimens were then sterilized in an ethylene oxide sterilizer for 24 hours. 2 mm of the reseated root was immersed in a culture chamber containing a Tripticase Soy Broth with a phenol red indicator. The coronal access of each specimen was inoculated every 72 hours with suspension of Proteus vulgaris. The culture media were observed every 24hours for color change indicating bacterial contamination. The specimens were observed for 4weeks. The remaining 70 teeth were submitted to a dye penetration test. The canals of all teeth were first sealed with AH26 and obturated using an Obtura II system. Root resection, root end preparation and retrograde filling was performed as above. All specimens were suspended in 2% methylene blue dye for 72 hours before being ion gitudinally split. The degree of dye penetration was then measured using a stereomicroscope at 10 magnification and evaluated. The results were as floows : 1. In the bacterial penetration, the degree of leakage was the lowest in the Super-EBA, followed by, in ascending order, ZOE, Chelon-Silver IRM and ZPC. The amalgam showed highest bacterial leakage of all(p<0.01). 2. In the dye penetration, the degree of microleakage was the lowest in the Chelon-Silver and Super-EBA, followed by, in ascending order, IRM, ZPC. The ZOE and amalgam showed the highest microleakage of all (p<0.05). These results suggested that the eugenol based cement, Super-EBA, have excellent sealing ability as a retrograde filling material.

• Physical Therapy Korea
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• v.27 no.1
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• pp.87-92
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• 2020

Background: Bridging exercises are used to enhance the functional stability of the lumbopelvic region in clinical settings. Although most of the studies on bridging exercises have compared the complete activation of the trunk muscles, some recent studies have examined the functional stability of the trunk and the lumbopelvic region and assessed the appropriate recruitment of the local and global muscles during different task levels. Objects: The purpose of this study was to investigate the changes in muscle thickness in the transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles during a common bridging exercise on an unstable surface and to determine whether these changes differ based on the surface used. Methods: Twenty-five healthy young adults (8 males, 17 females) were recruited. The subjects were randomly assigned to either the exercise progression with a sling bridge group or the ball bridging exercise progression group, each with three stages of increasing difficulty. Each position was measured three times with an ultrasonic diagnostic imaging system, and the mean values were recorded for analysis. Results: No significant differences were observed between the TrA, IO, or EO muscle thickness ratios between the sling and ball exercise groups (p > 0.05). There were also no significant differences in the EO muscle thickness ratios between the tasks irrespective of whether the sling or ball was used. However, the TrA and IO thickness ratios in both groups were significantly greater during stages 2 and 3 compared to stage 1. Conclusion: The results suggest that the use of slings and balls during bridging exercises is effective in activating the deep abdominal muscles.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1809-1811
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• 2000

High power piezoelectric materials are presently being extensively developed for applications such as ultrasonic motors and piezoelectric transformer In this study, the piezoelectric and dielectric properties of $MnO_2$ doped $0.36Pb(Sc_{1/2}Nb_{1/2})O_{3}-0.25Pb(Ni_{1/3}Nb_{2/3})O_{3}-0.39PbTiO_3$ (hereafter PSNNT), which is the morphotropic phase boundary composition of the PSN-PNN-PT system were investigated. $MnO_2$-addition into the $0.36Pb(Sc_{1/2}Nb_{1/2})O_{3}-0.25Pb(Ni_{1/3}Nb_{2/3})O_{3}-0.39PbTiO_3$ composition increases the piezoelectric coefficient up to $k_{p}{\fallingdotseq}$55.6[%] and $Q_{m}{\fallingdotseq}$252. Moreover, $MnO_2$ addition makes tetragonal phase more stable with respect to rhombohedral phase.