• Journal of Korea Water Resources Association
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• v.36 no.5
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• pp.799-810
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• 2003

Hydrologic models generally require land surface analysis to different topographic parameters defined as direct or indirect input variables to the model. Specially GIS supply the these parameters from digital data set of land surface The sensitivity analysis to DEM(Digital Elevation Model) resolution and the threshold area are of GIS extracted digital data set applied GIUH(Geomorphological Instantaneous Unit Hydrograph)model is investigated. Also it is compared the responses of GIUH model as input data of stream networks from digital data set(blue line) of NGIS and those extracted from DEM of various grid sizes. The results shows that the GIUH model is significantly affected by the DEM resolution and threshold area. According to the results, DEM grid size is suitable from 25m to 50m. Also threshold area is in the range of 30%∼50% for exceedance probability.

• The Journal of Korean Physical Therapy
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• v.32 no.2
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• pp.121-125
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• 2020

Purpose: The purpose of this study was to evaluate the forced vital capacity and sway area of respiratory muscles taping with threshold inspiratory muscles training for 1 week. Methods: Nineteen stroke patients were divided into two groups: experimental group (respiratory muscles taping with threshold inspiratory muscles training, n=10) and control group (threshold inspiratory muscles training, n=9). Forced vital capacity tests were performed using a spirometer. The instrument records the forced vital capacity (FVC). COP excursion test was performed using Zebris. The instrument records the sway area. All tests were measured before and after intervention. Results: The experimental group and control group showed significant increase in FVC (p<0.05). The sway area showed a significant decrease only in the experimental group (p<0.05). The FVC and sway area was no significant difference between the two groups (p>0.05). Conclusion: Threshold inspiratory muscles training is an effective intervention for improving FVC. Threshold inspiratory muscles training with respiratory taping is an effective intervention for improving FVC and sway area. Threshold inspiratory muscles training with respiratory taping can improve balance ability.

• Korean Journal of Remote Sensing
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• v.25 no.3
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• pp.271-285
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• 2009

Multi-temporal satellite imagery can be changed into a transform image that emphasizes the changed area only through the application of various change detection techniques. From the transform image, an automated change detection model calculates the optimal threshold value for classifying the changed and unchanged areas. However, the model can cause undesirable results when the histogram of the transform image is unbalanced. This is because the model uses a single threshold value in which the sign is either positive or negative and its value is constant (e.g. -1, 1), regardless of the imbalance between changed pixels. This paper proposes an advanced method that can improve accuracy by applying separate threshold values according to the increased or decreased range of the changed pixels. It applies multiple threshold values based on the cumulative producer's and user's accuracies in the automated binary change detection model, and the analyst can automatically extract more accurate optimal threshold values. Multi-temporal IKONOS satellite imagery for the Daejeon area was used to test the proposed method. A total of 16 transformation results were applied to the two study sites, and optimal threshold values were determined using accuracy assessment curves. The experiment showed that the accuracy of most transform images is improved by applying multiple threshold values. The proposed method is expected to be used in various study fields, such as detection of illegal urban building, detection of the damaged area in a disaster, etc.

• Journal of Environmental Science International
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• v.14 no.1
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• pp.33-40
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• 2005

The size of minimum order stream has a very sensitive effect on runoff analysis model using the divergence characteristic of stream. Therefore, in this study, the threshold area of minimum order stream has been examined the change characteristic of topographical parameters. The subject basin of the research was the upper basin of the Kumho water gage station which is located in the middle of the Kumho river. The 1:25,000 numerical geography which was constructed $10{\times}10m$ mesh was used. The range of investigation of topographical parameters are number of stream order, length, area, slope, basin relief, sinuosity ratio, drainage density and total stream length etc. It was found from the result of analysis that the threshold value of minimum order stream has a very big effect on topographical parameters of basin. It was found that the threshold area of minimum ord er stream revealed under $0.10km^{2}.$ Furthermore, the parameters showed a serious change except for over $0.10km^{2}.$

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.1B
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• pp.1-11
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• 2011

Channel network delineation from DEM (Digital Elevation Model) is a fundamental pre-process for hydrologic model application since it determines the drainage system in a watershed. This study aims to propose an effective and efficient channel network delineation process and assess the effects of DEM-based channel networks on the watershed drainage system. For these objectives, we applied two methods to generate the channel networks of the Jinan-cheon catchment with $18.28km^2$ from the 20 m resolution DEM: a widely-used area-threshold method and a slope-area threshold method based on the relationship between contributing areas and local slopes. The results showed that the area-threshold method led to unreliable drainage system, which did not satisfy geomorphological laws with respect to drainage density and source area representation whereas the slope-area threshold method provided acceptable results under the geomorphological laws. Our suggestions in this study can give valuable pre-processing information in DEM-based hydrologic modeling.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.65-68
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• 2005

In this paper, an algorithm to extract bar-space area is suggested. In a section of bar-code space area the threshold value is computed, and bar and space are extracted according to threshold value. PDF417 is used everyday life and printed in many different materials. The printed PDF417 is especially influenced by various light source. The decision of bar and space is very hard under the change of illumination. The fixed threshold value to distinguish the bar and space can not be applied. in these cases, The proposed algorithm is developed to investigate variable threshold. The variable threshold can be obtained by simple calculation.

• The Journal of Korean Physical Therapy
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• v.22 no.3
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• pp.17-21
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• 2010

Purpose: This study was designed to investigate possibilities for quantitative analysis using the electromyography and sonography. For better understanding, we evaluated the correlation between the pressure pain threshold and sonography, spontaneous electrical activity in trigger points located in the upper trapezius muscle. Methods: Thirty three active subjects volunteered to participate in this study (n=33). They had a palpable taut band, exquisite spot tenderness of a nodule in a taut band, spontaneous pain, referred pain, jump sign, local twitch response, and a painful limit to full stretch range of motion. We measured Pressure pain threshold, density, white area index, root mean square, and reaction. Pearson’s correlation coefficient was calculated to estimate the relationship between the pressure pain threshold and other variables including density, white area index, root mean square, and reaction time. Results: There were significant correlations between pressure pain threshold and density (r=-0.75, p<0.01), and between pressure pain threshold and white area index (r=-0.74, p<0.01). A significant correlations between pressure pain threshold and root mean square (r=-0.59, p<0.01). The significant correlation was found between pressure pain threshold and reaction time (r=-0.64, p<0.01). Conclusion: These should indicate whether quantitative analysis can be done using the characteristics of electromyography and sonography.

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.159-162
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• 1998

Land cover and land use classification on a huge scale, e.g. national or continental scale, has become more and more important because environmental researches need land cover: And land use data on such scales. We developed a crop field extraction method, which is one of the steps in our land cover classification system for a huge area. Firstly, a crop field model is defined to characterize "crop field" in terms of NDVI value and textual information Textual information is represented by the density of straight lines which are extracted by wavelet transform. Secondly, candidates of NDVI threshold value are determined by "scale-space filtering" method. The most appropriate threshold value among the candidates is determined by evaluating the line density of the area extracted by the threshold value. Finally, the crop field is extracted by applying level slicing to Landsat TM image with the threshold value determined above. The experiment demonstrates that the extracted area by this method coincides very well with the one extracted by visual interpretation.

• The Journal of Korean Physical Therapy
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• v.35 no.1
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• pp.31-35
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• 2023

Purpose: This study sought to identify whether fascial therapy using myofascial release (MFR) and Fascial Distortion Model (FDM) techniques affected not only the area where treatment was being given but also remote areas connected to the treatment area by fascial continuity through comparison of the pain pressure threshold (PPT). Methods: The subjects were 16 healthy normal adults in their 20s and 30s who were divided into the MFR and FDM groups before the experiment. The PPT was measured at 4 different points on the body of the subjects. C7, T7, L5, and gastrocnemius along the superficial back line (SBL) before and after the intervention. Results: Only the FDM group subjects showed a significant increase in the PPT at T7 after the intervention. (p<0.05). In addition, the FDM group demonstrated significantly increased PPT at L5 compared to the MFR group. However, neither the FDM nor the MFR group showed a meaningful change in the PPT at the remote area in the lower leg. Conclusion: These findings showed that FDM can affect PPT more and has a positive effect on the pain threshold compared to MFR. However, neither FDM nor MFR showed any effect on the PPT in a remote area.

• Journal of Oral Medicine and Pain
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• v.41 no.3
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• pp.85-90
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• 2016

Purpose: The aim of this study was to develop an automated software to extract tooth and pulpal area from sectional cone-beam computed tomography (CBCT) images, which can guarantee more reproducible, objective and time-saving way to measure pulp/tooth volume ratio. Methods: The software program was developed using MATLAB (MathWorks). To determine the optimal threshold for the region of interest (ROI) extraction, user interface to adjust the threshold for extraction algorithm was added. Default threshold was determined after several trials to make the outline of extracted ROI fitting to the tooth and pulpal outlines. To test the effect of starting point location selected initially in the pulpal area on the final result, pulp/tooth volume ratio was calculated 5 times with different 5 starting points. Results: Navigation interface is composed of image loading, zoom-in, zoom-out, and move tool. ROI extraction process can be shown by check in the option box. Default threshold is adjusted for the extracted tooth area to cover whole tooth including dentin, cementum, and enamel. Of course, the result can be corrected, if necessary, by the examiner as well as by changing the threshold of density of hard tissue. Extracted tooth and pulp area are reconstructed three-dimensional (3D) and pulp/tooth volume ratio is calculated by voxel counting on reconstructed model. The difference between the pulp/tooth volume ratio results from the 5 different extraction starting points was not significant. Conclusions: In further studies based on a large-scale sample, the most proper threshold to present the most significant relationship between age and pulp/tooth volume ratio and the tooth correlated with age the most will be explored. If the software can be improved to use whole CBCT data set rather than just sectional images and to detect pulp canal in the original 3D images generated by CBCT software itself, it will be more promising in practical uses.