• Proceedings of the Korean Society of Crop Science Conference
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• 2019.04a
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• pp.180-180
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• 2019

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.3
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• pp.394-403
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• 2009

As the minimally invasive approach against white spot like early caries lesions in proximal surfaces of the teeth, therapeutic sealing has been introduced and studied for effective materials and methods to arrest the early caries lesion effectively, which is still going on. This study was performed for the purpose of evaluating its validity for the non-cavitated lesions according to the depth from surface using therapeutic sealing followed by artificial caries induction and evaluation with micro-CT, and we obtained the results as follows. 1. It was revealed that the deeper the caries lesions are, the lower radiation intensity at lesion body areas in pre-treatment specimen. 2. In the sealed groups, there were no differences in radiation intensity between pre- and post-treatment, whereas there were significant decreases in unsealed groups(p<0.05). 3. Even in the specimens with the lesions reaching deeply into DEJ, the effect of sealing was significant(p<0.05). Conclusively, it was thought therapeutic sealing can be an effective tool against the early caries lesions, regardless of their depth into tooth, unless cavitated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.1957-1963
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• 2015

The purpose of this study is to examine the effect of dynamic stabilization exercise on unstable surface on thickness, muscle density and white area index (WAI) of transverse abdominis muscle and multifidus muscle. The subjects were 20s healthy adults and 27 people were measured for muscle thickness and muscle density, white area index after the experiment conducted during a six-week dynamic stabilization exercises divided into three groups, each in a different plane. The results showed a significant difference between the three groups (p <.05). Repeated measures analysis of variance (repeated ANOVA) results, transverse abdominis muscle and multifidus muscle thickness showed a significant difference between the groups in the time difference (p <.05), and between multifidus muscle density and white area index in the comparison between groups showed a significant difference (p <.05). In conclusion, showed significant difference in lumbar stabilization exercise part. These results seems to be utilized as a basis for future research on the lumbar stabilization exercise.

• Tunnel and Underground Space
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• v.26 no.4
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• pp.327-337
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• 2016

In this study, laboratory hydraulic fracturing tests are carried out to evaluate the effects of the cleavage anisotropy of Pocheon granite. Breakdown pressure is smaller when cracks are generated to the direction of rift plane in constant pressurization rate condition because of higher microcracks density. Besides not only injection rate changes but also the amount of injection pressure for fracture initiation and crack expansion is detected while testing due to internal deformation. Pressurization rate is higher while hydraulic fracture testing with constant injection rate condition in case of the specimen which has rift plane perpendicular to borehole because there are much flow paths to penetrate compared to the specimen which has hardway plane perpendicular to borehole. Observation by X-ray CT scanning shows that almost all of cracks due to hydraulic fracturing are generated to the direction of plane which has higher microcrack density that is rift plane or grain plane.

• The Optical Journal
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• s.91
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• pp.72-75
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• 2004

비구면의 사용으로 광학 설계자들은 최소의 렌즈로 보다 고성능의 광학계를 구현할 수 있게 되었다. 그러나 고정밀 비구면 렌즈는 제작이 까다롭고 비용이 많이 들기 때문에 특별한 용도로만 사용되고 있다. 최근 몇 년 사이에 전통적인 가공 방법과 비교하여 많은 장점을 가지고 있는 자기유동연마(magnetorheolpgical finishing)라는 새로운 비구면 가공기술이 개발되었다. 이 기술은 비구면의 장점을 더욱 다양하게 활용할 수 있도록 하는 첨단의 정밀

• The Journal of the Acoustical Society of Korea
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• v.29 no.4
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• pp.223-228
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• 2010

High-frequency bottom loss measurements for grazing angle of $82^{\circ}$ in frequency range 17-40 kHz were made in Jinhae bay in the southern part of Korea. Observations of bottom loss showed the strong variation as a function of frequency, which were compared to the predicted values using two-layered sediment reflection model. The geoacoustic parameters including sound speed, density and attenuation coefficient for the second sediment layer were predicted from the empirical relations with the mean grain size obtained from sediment core analysis. The geoacoustic parameters for the surficial sediment layer were inverted using Monte Carlo inversion algorithm. A sensitivity study for the geoacoustic parameters showed that the thickness of surficial sediment layer was most sensitive to the variation of the bottom loss.

• Economic and Environmental Geology
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• v.55 no.3
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• pp.295-307
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• 2022

We studied the Cretaceous Jeonggaksan Formation to determine depositional processes of pyroclastic density currents entering into the lacustrine environments. This formation is composed largely of sandstone-mudstone couplets and (tuffaceous) normally graded sandstones deposited in lacustrine environments, interbedded with two pyroclastic beds: welded massive lapilli tuff and normally graded lapilli tuff. The welded massive lapilli tuff (10 m thick) is composed of poorly sorted, structureless lapilli supported by a welded ash matrix. The normally graded lapilli tuff (4 m thick) is characterized by moderately to well sorted natures and multiple normally graded divisions in the lower part of the bed with internal boundaries. The contrasting depositional features between these lapilli tuff are suggestive of different physical characteristics and depositional processes of pyroclastic density currents in the lake. Overall poorly sorted and massive natures of the thick, welded massive lapilli tuff are interpreted to have been formed by rapid settling of pyroclastic sediments from highly concentrated and sustained pyroclastic density currents. In this case, the pyroclastic density currents were able to displace lake water from shoreline and the pyrolclastic density currents preserved their own heat except for frontal parts of the currents. As a result, welded textures can be formed despite entrance of pyroclastic density currents into the lake. The internal boundaries of the normally graded lapilli tuff reflect unsteady natures of the pyroclastic density currents at the time of the deposition and the pyroclastic density currents can not provide sufficient pressure to displace lake water. As a consequence, the pyroclastic density currents transformed into water-saturated turbidity currents, forming relatively well sorted, normally graded lapilli tuff.

• Proceedings of the KSRS Conference
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• 2009.03a
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• pp.360-366
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• 2009

AQUA/AMSR-E 인공위성 자료를 활용하여 3차원 최적내삽 해수면온도 합성장을 생산하였고 시간평균장과 비교하여 문제점과 한계점을 기술하였다. 3-D SST 합성장은 북태평양 중앙부에서 전체적으로 $0.05^{\circ}C$ 이하의 작은 오차를 보였으나, 위성 결측이 있는 연안에서는 $0.4^{\circ}C$ 이상의 비교적 큰 오차를 유발하였다. 강한 강수나 구름으로 인한 결측이 있는 부분에서는 $0.1\sim0.15^{\circ}C$에 달하는 오차를 보였다. 시간평균장과 비교한 결과, 구름 부근의 화소에서는 해수면온도를 낮게 계산하는 경향이 있었으며, 해수면온도의 공간적 구배를 감소시키는 평활화가 전체적으로 나타났다. 저위도에서 OI SST는 실제 해수면온도에는 없는 불연속성을 만드는 경향이 있었고, 이는 OI 과정에서 사용한 윈도우의 크기와 해양 현상의 수평 규모가 위도에 따라 변화하는데서 기인하였다. 현상의 공간 규모의 척도인 로스비 내부 변형 반경은 북태평양에서 O(1) 정도로 위도에 따른 공간적 변화가 큰 것으로 나타났다. 본 연구는 SST 합성장 생산 과정에 위도와 해수의 수직적 밀도 구조와 밀접한 관련이 있는 해양 현상의 수평적 규모의 시공간적 변동 특성을 고려해야 함을 제시한다.

• The KIPS Transactions:PartB
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• v.19B no.3
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• pp.201-208
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• 2012

Accurately segmenting lumen border in intravascular ultrasound images (IVUS) is very important to study vascular wall architecture for diagnosis of the cardiovascular diseases. After each of IVUS image is transformed to a polar coordinated image, initial points are detected using wavelet transform. Then, lumen border is initialized as the set of important points using non parametric probability density function and smoothing function by removing outlier initial points occurred by noises and artifacts. Finally, polynomial curve fitting is applied to obtain real lumen border using filtered important points. The evaluation of proposed method was performed with related method and the proposed method produced accurate lumen contour detection when compared to another method in most types of IVUS images.

• Korean Journal of Optics and Photonics
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• v.11 no.1
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• pp.58-64
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• 2000

Assuming that the performance of holographic storage media is ideal, we estimate the area storage density of disk-type holographic memories, when the method of either angle multiplexing, or rotational multiplexing, or both are used. The area storage density is strongly dependent on the f numbers (ratio of focal length to diameter) of both the Fourier transform lens in the signal arm, denoted by $F/#_2$, and the angle range over which the reference beam is incident (or, the equivalent f number corresponding to the angle range denoted by $F/#_1$). The area storage density is largely independent of the pixel pitch of the spatial light modulator when the Fourier plane holograms are recorded, while it is sensitive to the pixel pitch when the image plane holograms are recorded. In general, to obtain high area storage density, the Fourier or at least near Fourier plane holograms rather than the image plane holograms should be recorded. In addition, when the thickness of the recording materials are less than approximately $500\mu\extrm{m}$, rotational multiplexing gives higher area storage densities than angle multiplexing does. To increase the storage density further, however, it is desirable to use both of the two multiplexing methods in combination.nation.