• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.9
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• pp.977-982
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• 2011

The horizontal force acting on a work roll was examined. This force results from the contact force between the work roll and backup roll in a backup-roll-drive 4-high cold-rolling mill. This horizontal force bends the work roll horizontally and therefore exerts reciprocal action on the roll-gap contour. An analytical model for predicting the horizontal force acting on a work roll, which generates a mean value in the steady state, was presented. The material used for the analysis was high-silicon steel (about 3% Si). A three-dimensional finite element (FE) model was also employed to investigate the non-steady-state behavior of the horizontal force. Results showed that the horizontal force varied with the off-center distance between the work roll and backup roll. In addition, the optimal off-center distance was determined to minimize the horizontal force.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.3
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• pp.313-321
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• 2002

Supplying high-resolution satellite image, we take much interest in the update and the revision of digital map and thematic map based on the satellite image. This study presented the possibility of the update and the revision to the existing digital map on a scale of l/5,000 and 1/25,000 to take advantage of the IKONOS satellite image. We performed geometric correction to make use of the ground control points of the existing digital map in IKONOS mono-image and created ortho-image by extracting digital elevation model from three dimensional contour data and altitude on the existing digital map. We revised changed features in the method of screen digitizing by overlapping orthorectified satellite image and existing digital map and flawed features of the unchanged area on the satellite images for positional accuracy analysis. As a result, rectification error is calculated at $\pm$3.35m by RMSE. There is a good possibility of update of digital map under the scale of 1/10,000. It is possible to the update of the large scale digital map over the scale of l/5,000, as if we used the method of stereo image and ground control point surveying.

• Journal of Korean Neurosurgical Society
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• v.39 no.4
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• pp.256-259
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• 2006

Objective : Having a reliable and reproducible measurement technique to measure the sagittal contour in vertebral fractures is paramount to clinical decision making. This study is designed to determine the most reliable measurement technique in osteoporotic vertebral compression fracture. Methods : Fifteen lateral radiographs of thoracic and lumbar fractures were selected and measured on two separate occasions by three spine surgeons using six different measurement techniques [Centroid, Harrison Posterior Tangent Methods and 4 different types of modified Cobb method]. The radiograph quality was assessed and the center beam location was determined. Statistical analysis including ANOVA for repeated measures was carried out using the SAS software [v 8.0]. Results : The inter and intraobserver variance of the Cobb method 4 and Harrison posterior tangent method were significantly lower than the other four methods. The intraobserver correlation coefficients were the most consistent using the Cobb method 4 [0.982]. which was followed by the Harrison posterior tangent [0.953] and Cobb methods 1 [0.874]. The intraobserver agreement [% of repeated measures within 5 degrees of the original measurement] ranged from 42% to 98% for each technique for all three observers, with the Cobb method 4 showing the best agreement [97.8%] followed by the Harrison posterior tangent method [937%]. Conclusion : The Cobb method-4 and Harrison posterior tangent methods, when applied to measuring the kyphosis, are reliable and have a similar small error range. The Cobb method 4 shows the best overall reliability. However, the centroid method and Cobb method using a fractured endplate do not produce an accurate result due to inter and intraobserver differences in determining the baseline.

• International Journal of Industrial Entomology and Biomaterials
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• v.22 no.2
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• pp.65-74
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• 2011

The Scarites aterrimus (Coleoptera: Carabidae), is one of the carabid beetles dwelling exclusively on coastal sandy dunes. Habitat deterioration and equivalent activity have greatly concerned population declines in several species dwelling on the coastal sandy dunes. As a first step to establish long-term conservation strategy, we investigated the nation-wide magnitude and nature of genetic diversity of the species. As a first step, we sequenced a portion of mitochondrial COI gene, corresponding to "DNA Barcode" region (658 bp) from a total of 24 S. aterrimus individuals collected over nine sandy dunes belonging to four Korean provinces. The sequence analysis evidenced moderate to low magnitude of sequence diversity compared with other insect species distributed in Korean peninsula (0.152% to 0.912%). The presence of closely related haplotypes and relatively high gene flow estimate collectively suggest that there had been no historical barriers that bolster genetic subdivision. Population decline was postulated on the basis of several missing haplotypes that are well found in the species with a large population size. This interpretation is consistent with field observation of small population size in the coastal sandy dune habitats. The highest genetic diversity estimates were found in the coastal sand dune population of Seogwipo, Jeju Island, justifying a prior attention to the population, in order to sustain overall genetic diversity of the species. Further scrutinized study might be required for further robust conclusion.

• Phonetics and Speech Sciences
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• v.13 no.3
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• pp.31-37
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• 2021

The fundamental frequency, or f0, is an important acoustic measure in the prosody of human speech. The current study examined the f0 distribution of a corpus of spontaneous speech in order to provide normative data for Korean speakers. The corpus consists of 40 speakers talking freely about their daily activities and their personal views. Praat scripts were created to collect f0 values, and a majority of obvious errors were corrected manually by watching and listening to the f0 contour on a narrow-band spectrogram. Statistical analyses of the f0 distribution were conducted using R. The results showed that the f0 values of all the Korean speakers were right-skewed, with a pointy distribution. The speakers produced spontaneous speech within a frequency range of 274 Hz (from 65 Hz to 339 Hz), excluding statistical outliers. The mode of the total f0 data was 102 Hz. The female f0 range, with a bimodal distribution, appeared wider than that of the male group. Regression analyses based on age and f0 values yielded negligible R-squared values. As the mode of an individual speaker could be predicted from the median, either the median or mode could serve as a good reference for the individual f0 range. Finally, an analysis of the continuous f0 points of intonational phrases revealed that the initial and final segments of the phrases yielded several f0 measurement errors. From these results, we conclude that an examination of a spontaneous speech corpus can provide linguists with useful measures to generalize acoustic properties of f0 variability in a language by an individual or groups. Further studies would be desirable of the use of statistical measures to secure reliable f0 values of individual speakers.

• The Journal of Engineering Geology
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• v.31 no.3
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• pp.257-267
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• 2021

Constraints on the structure and composition of the active layer are important for understanding permafrost evolution. Soil convection owing to repeated moisture-induced freeze-thaw cycles within the active layer promotes the formation of self-organized patterned ground. Here we present the results of ground penetrating radar (GPR) surveys across a selected sorted circle near King Sejong Station, Antarctica, to better delineate the active layer and its relation to the observed patterned ground structure. We acquire GPR data in both bistatic mode (common mid-points) for precise velocity constraints and monostatic mode (common-offset) for subsurface imaging. Reflections are derived from the active layer-permafrost boundary, organic layer-weathered soil boundary within the active layer, and frozen rock-fracture-filled ice boundary within the permafrost. The base of the imaged sorted circle possesses a convex-down shape in the central silty zone, which is typical for the pattern associated with convection-like soil motion within the active layer. The boundary between the central fine-silty domain and coarse-grained stone border is effectively identified in a radar amplitude contour at the assumed active layer depth, and is further examined in the frequency spectra of the near- and far-offset traces. The far-offset traces and the traces from the lower frequency components dominant on the far-offset traces would be associated with rapid absorption of higher frequency radiowave due to the voids in gravel-rich zone. The presented correlation strategies for analyzing very shallow, thin-layered GPR reflection data can potentially be applied to the various types of patterned ground, particularly for acquiring time-lapse imaging, when electric resistivity tomography is incorporated into the analysis.

• Phonetics and Speech Sciences
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• v.13 no.1
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• pp.73-79
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• 2021

This study investigated the change in lip movement during speech according to aging. For the study, 15 elderly women with an average of 69 years and 15 young women with an average of 22 years were selected. To measure the movement of the lips, the ratio between the minimum point and the maximum point of movement when pronouncing a double vowel was analyzed in pixel units using image analysis software. For clinical utility, the software was produced by applying an automated algorithm and compared with the results of handwork. This study found that the range of the width and length of lips in double vowel tasks was smaller for the elderly than that of the young. A strong positive correlation was found between manual and automated methods, indicating that both methods are useful for extracting lip contours. Based on the above results, it was found that the range of the lips decreased when ignited as aging progressed. Therefore, monitoring the condition of lip performance by simply measuring the movement of lips before aging progresses, and performing exercises to maintain lip range, will prevent pronunciation problems caused by aging.

• Archives of Plastic Surgery
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• v.48 no.1
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• pp.3-9
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• 2021

Background For an attractive and natural tip contour in Asian rhinoplasty, insertion of a nasal implant and reinforcement of the cartilaginous framework are essential. However, scar contracture, which often results from augmentation with implant insertion and inadequate soft tissue coverage of the framework, is one of the most common causes of alar retraction. This study reports a novel method of redraping soft tissue along the alar rim to prevent alar retraction in Asians. Methods Twenty young Asian men who underwent primary rhinoplasty with septoplasty were retrospectively reviewed. After the usual rhinoplasty procedures, alar rim redraping was conducted for the soft tissue along the transcolumellar and bilateral infracartilaginous incisions. The longest axis of the nostril (a) and the height of the nostril from that axis (b) were measured in anterior-posterior and lateral views. The preoperative and postoperative ratios (b/a) were analyzed using the paired t-test. Results All 20 patients showed natural contours of the nasal tip, nostrils, and alae after a mean follow-up of 53.6 weeks (range, 52-60 weeks). The ratio of the nostril axes significantly decreased postoperatively in all patients except one, by an average of 11.08%±6.52% in the anterior-posterior view and 17.74%±8.49% in the lateral view (P<0.01). There were no complications, including asymmetry, contracture, subdermal plexus injury, flap congestion, or infection. Conclusions A quantitative analysis of alar retraction by evaluating the ratio of nostril axes showed that alar rim redraping is a simple and effective adjuvant technique for preventing alar retraction in rhinoplasty for young Asian men.

• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.96-102
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• 2022

Reactants of PEMFC are hydrogen and oxygen in gas phases and fuel cell overpotential could be reduced when reactants are smoothly transported. Numerous studies to modify cathode flow field design have been conducted because oxygen mass transfer in high current density region is dominant voltage loss factor. Among those cathode flow field designs, a block in flow field is used to forced supply reactant gas to porous gas diffusion layer. In this study, the block was installed on a simple fuel cell model. Using computational fluid dynamics (CFD), effects of forced convection due to blocks on a polarization curve and local current density contour were studied when different air flow rates were supplied. The high current density could be achieved even with low air supply rate due to forced convection to a gas diffusion layer and also with multiple blocks in series compared to a single block due to an increase of forced convection effect.

• Journal of People, Plants, and Environment
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• v.24 no.1
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• pp.39-51
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• 2021

Background and objective: Urban topology can be characterized as impervious, which changes the hydrologic features of an area, increasing surface water flow during local heavy rain events. The pluvial flooding is also influenced by the vertical structures of the urban area. This study suggested a modified digital elevation model (DEM) to identify changes in urban hydrological conditions and segmentalized urban micro catchment areas using a geographical information system (GIS). Methods: This study suggests using a modified DEM creation process based on Rolling Ball Method concepts along with a GIS program. This method proposes adding realized urban vertical data to normal DEM data and simulating hydrological analyses based on RBM concepts. The most important aspect is the combination of the DEM with polygon data, which includes urban vertical data in three datasets: the contour polyline, the locations of buildings and roads, and the elevation point data from the DEM. DEM without vertical data (DCA) were compared with the DEM including vertical data (VCA) to analyze catchment areas in Shin-wol district, Seoul, Korea. Results: The DCA had 136 catchments, and the area of each catchment ranged from 3,406 m² to 423,449 m². The VCA had 2,963 catchments, with the area of each ranging from 50 m² to 16,209 m². The most important finding is that in the overlapped VCA; the boundary of areas directly affected by flooding and the direction of surface water flow could be identified. Flooding data from September 21, 2010 and July 27, 2011 in the Shin-wol district were applied as ground reference data. The finding is that in the overlapped VCA; the boundary of areas directly affected by flooding and the direction of surface water flow could be identified. Conclusion: The analysis of the area vulnerable to surface water flooding (SWF) was more accurately determined using the VCA than using the DCA.