• Title/Summary/Keyword: correction

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Atmospheric Correction Issues of Optical Imagery in Land Remote Sensing (육상 원격탐사에서 광학영상의 대기보정)

  • Lee, Kyu-Sung
    • Korean Journal of Remote Sensing
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    • v.35 no.6_3
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    • pp.1299-1312
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    • 2019
  • As land remote sensing applications are expanding to the extraction of quantitative information, the importance of atmospheric correction is increasing. Considering the difficulty of atmospheric correction for land images, it should be applied when it is necessary. The quantitative information extraction and time-series analysis on biophysical variables in land surfaces are two major applications that need atmospheric correction. Atmospheric aerosol content and column water vapor, which are very dynamic in spatial and temporal domain, are the most influential elements and obstacles in retrieving accurate surface reflectance. It is difficult to obtain aerosol and water vapor data that have suitable spatio-temporal scale for high- and medium-resolution multispectral imagery. Selection of atmospheric correction method should be based on the availability of appropriate aerosol and water vapor data. Most atmospheric correction of land imagery assumes the Lambertian surface, which is not the case for most natural surfaces. Further BRDF correction should be considered to remove or reduce the anisotropic effects caused by different sun and viewing angles. The atmospheric correction methods of optical imagery over land will be enhanced to meet the need of quantitative remote sensing. Further, imaging sensor system may include pertinent spectral bands that can help to extract atmospheric data simultaneously.

Precise Gravity Terrain Correction of Gravity Exploration for Small Anomalous Bodies (소규모 이상체의 중력탐사를 위한 정밀지형보정)

  • Lee, Heui-Soon;Rim, Hyoung-Rea
    • Journal of the Korean earth science society
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    • v.31 no.1
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    • pp.1-7
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    • 2010
  • Many studies have successfully developed a number of terrain correction programs in gravity data. Furthermore, terrain data that is a basic data for terrain correction has widely been provided through internet. We have also developed our own precise gravity terrain correction program. The currently existing gravity terrain correction programs have been developed for regional scale gravity survey, thus a more precise gravity terrain correction program needs to be developed to correct terrain effect. This precise gravity terrain program can be applied on small size geologic targets, such as small scale underground resources or underground cavities. The multiquadric equation has been applied to create a mathematical terrain surface from basic terrain data. Users of this terrain correction program can put additional terrain data to make more precise terrain correction. In addition, height differences between terrain and base of gravity meter can be corrected in this program.

Analysis of Cleft Lip Nose Deformities Correction in Adults: Detailed Techniques and Comprehensive Review (성인에서의 구순비변형 교정술에 사용된 상세술기의 분석)

  • Choi, Chi-Won;Kang, Kyung-Dong;Kim, Kyoung-Hoon;Bae, Yong-Chan
    • Archives of Plastic Surgery
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    • v.38 no.6
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    • pp.755-760
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    • 2011
  • Purpose: Correction of cleft lip nose deformity (CLND) in adulthood is different from one in childhood. Usually correction of CLND is final surgery for adult patient who has cleft lip, so many things have to be considered for correction. Of course, it is different from common rhinoplasty, either. The adult patients can be corrected by complete rhinoplasty with various techniques. To recognize how rhinoplasty techniques was used for correction of CLND, authors analyzed detailed techniques which were selected in the adult patients for 10 years and reviewed comprehensive operation. Methods: A retrospective review was conducted involving 64 patients with CLND who underwent surgery and aged after 14 years at operation between 2001 and 2010. Detailed techniques were investigated by medical record review and classified according to incision, septoplasty, osteotomies, correction of vault, tip plasty and etc. Results: Except one, all patients were performed open rhinoplasty. 49 patients were performed septoplasty. 33 patients were performed complete rhinoplasty with osteotomies. Hump nose correction was performed for 10 patients. Dorsal augmentation was performed for 8 patients. And all patients were performed tip plasty. Tip plasty using suture technique was performed for 58 patients and graft was performed for 48 patients. Conclusion: Correction of CLND in adult is one of the most challenging and varied operation of plastic surgery. In this study, the majority of patients were performed complicated and delicated procedures. It seems to be because patient's demand level has been elevated and rhinoplasty procedures have been advanced. This study may help to planning of CLND correction.

Aerodynamic Corrections for Load Analysis of Micro Aerial Vehicle (초소형 비행체 하중해석을 위한 공력보정)

  • Koo, Kyo-Nam
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.6
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    • pp.31-38
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    • 2005
  • Aerodynamic influence coefficient linearly relates pressure with downwash in panel method for load analysis in which the viscosity of a flow is ignored and the compressibility cannot be taken into account in transonic region. Since the planform of an aerodynamic surface determines the coefficient, the panel method has a limit to the analysis of low Reynolds number flow. The accuracy of the pressure distribution can be improved by a direct correction to the pressure or a correction to the downwash, which is considered the change of camber or thickness, using the aerodynamic coefficients from wind tunnel test as constraints. A premultiplying correction method as well as a postmultiplying correction method is applied to a micro air vehicle to provide more accurate aerodynamic pressure for trim and load analyses. Theoretical aerodynamic pressure is obtained from the panel method. Correction factor matrix and correct pressure coefficient are computed for the conditions with two constraints in addition to single constraint. The postmultiplying correction method gives a better improvement in pressure distribution on micro air vehicle due to the flow characteristics on it.

A Study on the Posture Maintenance Performance and Self-Efficacy in accordance with Posture Correction Program (자세교정프로그램에 따른 자세유지 수행과 자기효능감에 관한 연구)

  • Jang, Su-Gyeong
    • Journal of Korean Physical Therapy Science
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    • v.7 no.2
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    • pp.459-474
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    • 2000
  • The purpose of this study is to identify the posture correction program as the development of the posture maintenance performance, and search for the more efficient posture correction program. The data analysis was processed by SPSS. The data was analysed with $x^2$-test, t-test, pearson product moment correlation, and stepwise regression analysis. The finding of this study is as follows: There are the homogeneity between two groups was verified on the know ledges CF=.697, df=2, P>.05), self-efficacy(F=.098, df=2, P>.05) about the posture. The developed posture correction program has proved to enhance the posture maintenance performance(knowledge t=1.60, P<.05 ; posture manintenance t=7.69, P<.01). The type of posture correction program showed some significant differences (t=5.62, P<.01) in the accuracy of movement way among the factors of the posture maintenance performance. The posture maintenance performance affected self-efficacy. Therefore, the major conclusion is as follows: The posture correction program was meaningfully effective on developing the posture maintenance, and with practice created accuracy much more on the posture maintenance movement way. The development of the posture maintenance performance affected the increase of self-efficacy about the posture. The self-efficacy has proved so powerful factor to influence on the posture maintenance performance development. So, the posture correction program should be done systematically and continually, and developing the posture maintenance performance should be done with practice. After the education, it should be reinforced through practice, midterm identification and reeducation and motivated with recognizing the accurate posture measurement. And it should be created the correction program to develop the high self-efficacy about the posture. It needs the strategy to educate the correct posture individually, and to spread to the society for healthy life style.

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A Spelling Error Correction Model in Korean Using a Correction Dictionary and a Newspaper Corpus (교정사전과 신문기사 말뭉치를 이용한 한국어 철자 오류 교정 모델)

  • Lee, Se-Hee;Kim, Hark-Soo
    • The KIPS Transactions:PartB
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    • v.16B no.5
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    • pp.427-434
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    • 2009
  • With the rapid evolution of the Internet and mobile environments, text including spelling errors such as newly-coined words and abbreviated words are widely used. These spelling errors make it difficult to develop NLP (natural language processing) applications because they decrease the readability of texts. To resolve this problem, we propose a spelling error correction model using a spelling error correction dictionary and a newspaper corpus. The proposed model has the advantage that the cost of data construction are not high because it uses a newspaper corpus, which we can easily obtain, as a training corpus. In addition, the proposed model has an advantage that additional external modules such as a morphological analyzer and a word-spacing error correction system are not required because it uses a simple string matching method based on a correction dictionary. In the experiments with a newspaper corpus and a short message corpus collected from real mobile phones, the proposed model has been shown good performances (a miss-correction rate of 7.3%, a F1-measure of 97.3%, and a false positive rate of 1.1%) in the various evaluation measures.

Correction of Fluoroscopic Image for Nucleoplasty in Lumbar Disc (요추디스크 수핵감압술을 위한 투시영상의 교정)

  • Yun, Young Woo;Kang, Se Sik;Choi, Seok Yoon
    • Journal of the Korean Society of Radiology
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    • v.10 no.5
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    • pp.359-365
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    • 2016
  • Fluoroscopy is performed when tissue or organ in the human body is examined, and it is used for diagnosis and procedure in back ailments. With regard to fluoroscopy equipment, distortion occurs on the peripheral part of fluoroscopic image rather than on its central part. This study measured distortion factors of vertical spacing ratio and distortion factor of diagonal spacing ratio before and after correction by applying a correction algorithm. According to measuring the vertical spacing ratio, post-correction standard deviation decreased by 0.04 in comparison with pre-correction one. Also measuring the diagonal spacing ratio, post-correction standard deviation decreased by 0.06 in comparison with pre-correction one. Consequently, the distortion of fluoroscopic image decreased after correction. A decrease in the distortion of image through the application of correction algorithm and the improvement of performance will be helpful in finding a correct position of lumbar puncture in nucleoplasty to treat lumbar disc herniation in the future.

Uncertainty in Regional Climate Change Impact Assessment using Bias-Correction Technique for Future Climate Scenarios (미래 기상 시나리오에 대한 편의 보정 방법에 따른 지역 기후변화 영향 평가의 불확실성)

  • Hwang, Syewoon;Her, Young Gu;Chang, Seungwoo
    • Journal of The Korean Society of Agricultural Engineers
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    • v.55 no.4
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    • pp.95-106
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    • 2013
  • It is now generally known that dynamical climate modeling outputs include systematic biases in reproducing the properties of atmospheric variables such as, preciptation and temerature. There is thus, general consensus among the researchers about the need of bias-correction process prior to using climate model results especially for hydrologic applications. Among the number of bias-correction methods, distribution (e.g., cumulative distribution fuction, CDF) mapping based approach has been evaluated as one of the skillful techniques. This study investigates the uncertainty of using various CDF mapping-based methods for bias-correciton in assessing regional climate change Impacts. Two different dynamicailly-downscaled Global Circulation Model results (CCSM and GFDL under ARES4 A2 scenario) using Regional Spectial Model for retrospective peiod (1969-2000) and future period (2039-2069) were collected over the west central Florida. Total 12 possible methods (i.e., 3 for developing distribution by each of 4 for estimating biases in future projections) were examined and the variations among the results using different methods were evaluated in various ways. The results for daily temperature showed that while mean and standard deviation of Tmax and Tmin has relatively small variation among the bias-correction methods, monthly maximum values showed as significant variation (~2'C) as the mean differences between the retrospective simulations and future projections. The accuracy of raw preciptiation predictions was much worse than temerature and bias-corrected results appreared to be more significantly influenced by the methodologies. Furthermore the uncertainty of bias-correction was found to be relevant to the performance of climate model (i.e., CCSM results which showed relatively worse accuracy showed larger variation among the bias-correction methods). Concludingly bias-correction methodology is an important sourse of uncertainty among other processes that may be required for cliamte change impact assessment. This study underscores the need to carefully select a bias-correction method and that the approach for any given analysis should depend on the research question being asked.

Colour Interpolation of Tongue Image in Digital Tongue Image System Blocking Out External Light (디지털 설진 시스템의 색상 보정)

  • Kim, Ji-Hye;Nam, Dong-Hyun
    • The Journal of the Society of Korean Medicine Diagnostics
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    • v.16 no.1
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    • pp.9-18
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    • 2012
  • Objectives The aim of this study is to propose an optimized tongue colour interpolation method to achieve accurate tongue image rendering. Methods We selected 60 colour chips in the chips of DIC color guide selector, and then divided randomly the colour chips into two groups. The colour chips of a group (Gr I) were used for finding the optimized colour correction factor of error and those of the other group (Gr II) were used for verifying the correction factor. We measured colour value of the Gr I colour chips with spectrophotometer, and took the colour chips image with a digital tongue image system (DTIS). We adjusted colour correction factor of error to equal the chip colour from each method. Through that process, we obtained the optimized colour correction factor. To verify the correction factor, we measured colour value of the Gr II colour chips with a spectrophotometer, and took the colour chips image with the DTIS in the two types of colour interpolation mode (auto white balance mode and optimized colour correction factor mode). And then we calculated the CIE-$L^*ab$ colour difference (${\Delta}E$) between colour values measured with the spectrophotometer and those from images taken with the DTIS. Results In auto white balance mode, The mean ${\Delta}E$ between colour values measured with the spectrophotometer and those from images taken with the DTIS was 13.95. On the other hand, in optimized colour correction factor mode, The mean ${\Delta}E$ was 9.55. The correction rate was over 30%. Conclusions In case of interpolating colour of images taken with the DTIS, we suggest that procedure to search the optimized colour correction factor of error should be done first.