• The Journal of Engineering Geology
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• v.27 no.3
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• pp.305-312
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• 2017

The most effective way to distinguish subsurface interfaces that produce various geophysical responses is through the integration of multiple geophysical methods, with each method detecting both a complementary and unique set of distinct physical properties relating to the subsurface. In this study, shallow seismic reflection (SSR) and ground penetrating radar (GPR) surveys were conducted at the Cheongju-Gadeok site of the Korea National Groundwater Monitoring Network to map the water table, which was measured at 12 m depth during the geophysical surveys. The water table proved to be a good target reflector in both datasets, as the abrupt transition from the overlying unsaturated weathered rock to the underlying saturated weathered rock yielded large acoustic impedance and dielectric constant contrasts. The two datasets were depth converted and integrated into a single section, with the SSR and GPR surveys conducted to ensure subsurface imaging at approximately the same wavelength. The GPR data provided detailed information on the upper ~15 m of the section, whereas the SSR data imaged structures at depths of 10-45 m. The integrated section thus captured the full depth coverage of the sandy clay, water table, weathered rock, soft rock, and hard rock structures, which correlated well with local drillcore and water table observations. Incorporation of these two geophysical datasets yielded a synthetic section that resembled a simplified aquifer model, with the best-fitting seismic velocity, dielectric constant, and porosity of the saturated weathered layer being $v_{seismic}=1000m/s$, ${\varepsilon}_r=16$, and ${\phi}=0.32$, respectively.

• 한국석유지질학회:학술대회논문집
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• autumn
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• pp.14-30
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• 2000

Hierarchically controlled sequence stratigraphic analysis shows that the Lower Ordovician mixed carbonate-siliciclastic Mungok Formation, Korea consists of three depositional sequences: T1, T2, and T3. Sequence boundaries are generally marked by abrupt transition from coarse-grained shallow-water carbonates to fine-grained deeper-water carbonates mixed with fine-grained siliciclastics, and show indication of subaerial exposure such as karstification. Within this sequence stratigraphic framework, facies characteristics indicate that the Mungok sequences were mostly deposited in subtidal ramp environments. High-frequency cycles consist of upward-shallowing facies successions. Cycles of shallow-water and basinal deposits are not represented well, probably due to cycle amalgamation. Cycle stacking patterns do not show a consistent thickness change that reflects a large-scale sea-level change due to unfilled accommodation space. The Mungok sequences show that many factors including relative sea-level change and topography are involved in controlling sequence development on carbonate ramps. The depositional setting evolved from the high-energy ramps in the sequences T1 and T2 into the low-energy ramp in the sequence T3. Topography is interpreted to have been responsible for the different energy regimes of the carbonate ramps in the Mungok sequences. The high ramp gradient in the sequences T1 and T2 seems to be caused by space-time-dissociated differential sedimentation resulting in spatially narrow distribution of sediment filling, which in turn may be related to high rate of relative sea-level change. In contrast, low ramp gradient was maintained in the sequence T3 during slow changes of relative sea level resulting in broad distribution of sediment filling.

• Journal of the Korean Wood Science and Technology
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• v.29 no.3
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• pp.1-13
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• 2001

Compression, lateral, and opposite woods in the stem and branch of rimu (Dacrydium cupressinum Lamb.), a softwood species indigenous to New Zealand, were described and compared in the anatomical aspects. Qualitatively, growth rings were wide in the compression wood, intermediate in the lateral wood, and narrow in the opposite wood. Tracheid transition from early wood to late wood was very gradual in the compression wood but was more abrupt in both the lateral and opposite woods. When viewed transversely, compression wood tracheids showed a roundish outline except at the growth ring boundary but lateral and opposite wood tracheids were angular to rectangular in outline. Intercellular spaces were occasionally detected in the compression wood except in the late wood at the growth ring boundary but were absent from both the lateral and opposite woods. Slit-like extensions of the bordered pit openings caused by the location of pit apertures within short and narrow helical grooves were observed in the compression wood tracheids but not in the opposite or lateral wood tracheids. In the compression wood tracheids, fine striations in the form of fine checks or grooves were observed on the lumen surfaces and the innermost $S_3$ layer of secondary wall was absent. In the tracheids of lateral and opposite woods, the $S_3$ layer was sometimes absent but occasionally highly developed. Cross-field pits in the compression wood appeared to be piceoid due to slit-like pit apertures but those in the lateral and opposite wood tracheids showed cupressoid to taxodioid. Quantitatively, compression wood tracheids were somewhat shorter than those of opposite or lateral wood in stem but not different from the opposite or lateral wood tracheids in branch. The walls were thicker in the compression wood than in the lateral or opposite wood. Uniseriate rays in the compression wood were fewer than in the lateral or opposite wood.

• Journal of the Korean Wood Science and Technology
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• v.15 no.2
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• pp.79-89
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• 1987

This study was executed to examine helical structure and other feature, of Taxus cuspidata S. et Z. and Larix gmelinii var. principis-ruprechtii Pilger through photomicroscopic and scanning electron microscopic observation, and the obtained result, were summarized as follows: 1. Tracheid transition from springwood to summerwood was abrupt, mel slightly gradual in Taxus cuspidata S. et Z. and summerwood width of Larix gmelinii var. principis-ruprechtii Pilger was wider than that of Taxus cuspidata S. et Z. 2. Normal vertical and horizontal resin canals and surrounding thick epithelial cells were present in Larix gmelinii var. principis-ruprechtii Pilger but not present in Taxus cuspidata S. et Z. 3. Instead of helical thickening, helical chicks were observed only in summerwood trachieds of Larix gmelinii var. principis-ruprechtii Pilger. However, helical thickenings forming S, Z., and horizontal helix perpendicular to long axis of tracheid were observed in springood and summerwood tracheids of Taxus cuspidata S. et Z. and these helical thickenings were considered as analogous to the innermost layer of secondary wall. 4. Uniseriate and fusiform rays were appeared on tangential surface of Larix gmelinii var. principis-ruprechtii Pilger but oly uniserate ray was observed on tangential surface ot Taxus cuspidata S. et Z. The fusiform rays of Larix gmelinii var. principis-ruprechtii Pilger usually contained one horizontal resin canal bot occasionally two horizontal resin canals were contained in a fusiform ray. 5. Trabeculae and crassulae were observed in the tracheids of Larix gmelimii var. principis-ruprechtii Pilger but not observed in the tracheids of Taxus cuspidata S. et Z.

• Wind and Structures
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• v.30 no.4
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• pp.393-403
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• 2020

One of the growing concerns of the wind energy production is wind ramp events. To improve the wind ramp event forecasts, the nonlinear Kalman filter bias correction method was applied to 24-h wind speed forecasts issued from the WRF model at 70-m height in Zhangbei wind farm, Hebei Province, China for a two-year period. The Kalman filter shows the remarkable ability of improving forecast skill for real-time wind speed forecasts by decreasing RMSE by 32% from 3.26 m s_-1 to 2.21 m s_-1, reducing BIAS almost to zero, and improving correlation from 0.58 to 0.82. The bias correction improves the forecast skill especially in wind speed intervals sensitive to wind power prediction. The fact shows that the Kalman filter is especially suitable for wind power prediction. Moreover, the bias correction method performs well under abrupt weather transition. As to the overall performance for improving the forecast skill of ramp events, the Kalman filter shows noticeable improvements based on POD and TSS. The bias correction increases the POD score of up-ramps from 0.27 to 0.39 and from 0.26 to 0.38 for down-ramps. After bias correction, the TSS score is significantly promoted from 0.12 to 0.26 for up-ramps and from 0.13 to 0.25 for down-ramps.

• Elastomers and Composites
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• v.42 no.3
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• pp.143-150
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• 2007

Hardness of rubbery materials, which is important for dimensional stability and product performance, was investigated upon temperature change in this study. A newly developed IRHD (International Rubber Hardness Degree) tester was used to measure the hardness changes of NR and SBR specimens at various temperatures and the hardness values were compared with the Young's modulus. The harness and Young's modulus of NR and SBR showed an abrupt change near the glass transition temperatures. The hardness and Young's modulus were increased by increasing temperature due to the increased random chain conformation of molecules. The effect of temperature on hardness and Young's modulus of NR and SBR specimens filled with carbon black and silica was decreased by increasing filler content.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1996.06b
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• pp.285-309
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• 1996

Non oxide ceramics such as nitrides of transition metals have shown significant potential for future economic impact, in diverse applications in ceramic, aerospace and electronic industries, as refractory products, abrasives and cutting tools, aircraft components, and semi-conductor substrates amid others. Combustion synthesis has become an attractive alternative to the conventional furnace technology to produce these materials cheaply, faster and at a higher level of purity. However he process os highly exothermic and manifests complex dynamics due to its strongly non-linear nature. In order to develop an understanding of this process and to study the effect of operational parameters on the final outcome, numerical modeling is necessary, which would generated essential knowledge to help scale-up the process. the model is based on a system of parabolic-hyperbolic partial differential equations representing the heat, mass and momentum conservation relations. The model also takes into account structural change due to sintering and volumetric expansion, and their effect on the transport properties of the system. The solutions of these equations exhibit steep moving spatial gradients in the form of reaction fronts, propagating in space with variable velocity, which gives rise to varying time scales. To cope with the possibility of extremely abrupt changes in the values of the solution over very short distances, adaptive mesh techniques can be applied to resolve the high activity regions by ordering grid points in appropriate places. To avoid a control volume formulation of the solution of partial differential equations, a simple orthogonal, adaptive-mesh technique is employed. This involves separate adaptation in the x and y directions. Through simple analysis and numerical examples, the adaptive mesh is shown to give significant increase in accuracy in the computations.

• Journal of Audiology & Otology
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• v.23 no.2
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• pp.69-75
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• 2019

Background and Objectives: The antioxidant ebselen will be able to limit or prevent the ototoxicity arising from 2-hydroxypropyl-β-cyclodextrin (HPβCD). Niemann-Pick Type C (NPC) disease is a disorder of lysosomal storage manifested in sphingolipidosis. Recently, it was noted that experimental use of HPβCD could partially resolve the symptoms in both animals and human patients. Despite its desirable effect, HPβCD can induce hearing loss, which is the only major side effect noted to date. Understanding of the pathophysiology of hearing impairment after administration of HPβCD and further development of preventive methods are essential to reduce the ototoxic side effect. The mechanisms of HPβCD-induced ototoxicity remain unknown, but the resulting pathology bears some resemblance to other ototoxic agents, which involves oxidative stress pathways. To indirectly determine the involvement of oxidative stress in HPβCD-induced ototoxicity, we tested the efficacy of an antioxidant reagent, ebselen, on the extent of inner ear side effects caused by HPβCD. Materials and Methods: Ebselen was applied prior to administration of HPβCD in mice. Auditory brainstem response thresholds and otopathology were assessed one week later. Bilateral effects of the drug treatments also were examined. Results: HPβCD-alone resulted in bilateral, severe, and selective loss of outer hair cells from base to apex with an abrupt transition between lesions and intact areas. Ebselen co-treatment did not ameliorate HPβCD-induced hearing loss or alter the resulting histopathology. Conclusions: The results indirectly suggest that cochlear damage by HPβCD is unrelated to reactive oxygen species formation. However, further research into the mechanism(s) of HPβCD otopathology is necessary.

• Korean Journal of Audiology
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• v.23 no.2
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• pp.69-75
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• 2019

Background and Objectives: The antioxidant ebselen will be able to limit or prevent the ototoxicity arising from 2-hydroxypropyl-β-cyclodextrin (HPβCD). Niemann-Pick Type C (NPC) disease is a disorder of lysosomal storage manifested in sphingolipidosis. Recently, it was noted that experimental use of HPβCD could partially resolve the symptoms in both animals and human patients. Despite its desirable effect, HPβCD can induce hearing loss, which is the only major side effect noted to date. Understanding of the pathophysiology of hearing impairment after administration of HPβCD and further development of preventive methods are essential to reduce the ototoxic side effect. The mechanisms of HPβCD-induced ototoxicity remain unknown, but the resulting pathology bears some resemblance to other ototoxic agents, which involves oxidative stress pathways. To indirectly determine the involvement of oxidative stress in HPβCD-induced ototoxicity, we tested the efficacy of an antioxidant reagent, ebselen, on the extent of inner ear side effects caused by HPβCD. Materials and Methods: Ebselen was applied prior to administration of HPβCD in mice. Auditory brainstem response thresholds and otopathology were assessed one week later. Bilateral effects of the drug treatments also were examined. Results: HPβCD-alone resulted in bilateral, severe, and selective loss of outer hair cells from base to apex with an abrupt transition between lesions and intact areas. Ebselen co-treatment did not ameliorate HPβCD-induced hearing loss or alter the resulting histopathology. Conclusions: The results indirectly suggest that cochlear damage by HPβCD is unrelated to reactive oxygen species formation. However, further research into the mechanism(s) of HPβCD otopathology is necessary.

• Journal of Korea Multimedia Society
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• v.14 no.10
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• pp.1252-1261
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• 2011

In this paper, we propose the comparison method of pattern similarity for video segmentation algorithm. The shot boundary type is categorized as 2 types, abrupt change and gradual change. The representative examples of gradual change are dissolve, fade-in, fade-out or wipe transition. The proposed method consider the problem to detect shot boundary as 2-class problem. We concentrated if the shot boundary event happens or not. It is essential to define similarity between frames for shot boundary detection. We proposed 2 similarity measures, within similarity and between similarity. The within similarity is defined by feature comparison between frames belong to same shot. The between similarity is defined by feature comparison between frames belong to different scene. Finally we calculated the statistical patterns comparison between the within similarity and between similarity. Because this measure is robust to flash light or object movement, our proposed algorithm make contribution towards reducing false positive rate. We employed color histogram and mean of sub-block on frame image as frame feature. We performed the experimental evaluation with video dataset including set of TREC-2001 and TREC-2002. The proposed algorithm shows the performance, 91.84% recall and 86.43% precision in experimental circumstance.