• 한국수자원학회논문집
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• 제36권5호
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• pp.799-810
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• 2003

일반적으로 수문모형은 직접 또는 간접적으로 정의되는 지형매개변수에 대한 지형학적 해석을 필요로 한다. GIS는 지형의 수치자료로부터 이러한 매개변수를 추출하여 제공할 수 있다. 따라서 본 연구는 수치지형도상의 실제 하천망 및 threshold area를 추출하고, 정방행렬의 고도수치를 표현하는 수치고도모형(Digital Elevation Model :DEM)로부터 하천망을 추출시, 실제 지형도상에서 나타나는 threshold area의 통계적 변화에 따른 변화를 검토하였다. 또한 실제 수치지형도에서 추출한 유역의 지형매개변수와 DEM으로부터 추출한 지형매개변수를 지형학적 순간단위도(Geomorphological Instantaneous Unit Hydrgraph : GIUH)모형의 입력자료로 활용될 때, DEM의 격자 크기와 하천망 추출에 필요한 threshold area의 변화에 대한 유역 특성 고유치의 민감도를 분석한 것이다. 본 연구 결과 DEM의 격자크기와 threshold area의 변화에 따라 GIUH 모형은 민감하게 변화하고 있음을 알 수 있었으며, 보청천 산성교 적용 대상지역의 경우 DEM격자크기는 25m∼50m의 크기가 적정하고, 하천망을 추출할 때 사용되는 threshold area는 초과확률 30%∼5o%크기가 적정함을 보여줬다.

• The Journal of Korean Physical Therapy
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• 제32권2호
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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.

• 대한원격탐사학회지
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• 제25권3호
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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.

• 한국환경과학회지
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• 제14권1호
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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 $0.10km^{2}.$

• 대한토목학회논문집
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• 제31권1B호
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• pp.1-11
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• 2011

DEM을 이용한 수로망의 생성은 수문해석모형의 적용을 위한 전처리 과정으로써 실제 유역시스템의 배수구조를 결정하는 중요한 인자로 활용된다. 본 연구에서는 DEM으로부터 합리적인 수로망 추출과정 수립을 목적으로 보편적으로 사용되고 있는 면적한계기준과 국부경사와 기여면적사이의 특성에 근거한 경사-면적한계기준 기법을 이용하여 수로망을 생성하고 지형법칙에 의거하여 각 기법에 따른 소규모 유역(진안천 유역; $18.28km^2$) 배수구조의 신뢰성을 평가하였다. 그 결과, 면적한계 기준 기법은 수원유역의 크기의 인위적 결정에 의해 지형법칙을 만족시키지 못하고 유역전체의 배수구조를 왜곡되게 묘사한 반면, 경사-면적한계기준 기법의 경우 물리적인 지형법칙을 만족시키는 우수한 결과를 나타냈다. 따라서 경사-면적한계기준 기법은 DEM 기반의 수문모형을 적용 시 효율적이고 객관적인 수로망 생성을 위한 방법론으로서 활용이 가능하리라 판단된다.

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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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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• 제22권3호
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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.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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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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• 제35권1호
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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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• 제41권3호
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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.