• 제목/요약/키워드: Curvature Correction

검색결과 91건 처리시간 0.027초

A Note on Test for Model Adequacy in Nonlinear Regression

  • Kahng, Myung-Wook
    • Journal of the Korean Data and Information Science Society
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    • 제15권3호
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    • pp.689-694
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    • 2004
  • We investigate the test for model adequacy in nonlinear regression. We can expect the usual likelihood ratio statistic to be unaffected by any parametric- effect curvature; only the effect of intrinsic curvature needs to be considered. Multiplicative correction factor is derived for the limiting distribution of test statistic, which is a function of the intrinsic curvature arrays.

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척추측만증보조기 착용에 따른 만곡각도와 체질량지수의 관계 (Relationship Between Curvature Angle and BMI According to Wearing a Scoliosis Brace)

  • 이광호
    • 대한통합의학회지
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    • 제7권3호
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    • pp.149-157
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    • 2019
  • Purpose : This study aims to check the relationship between the size of curvature in scoliosis patients and the reduction rate of curvature after wearing a brace and the relationships of the size of curvature and correction angle with Body Mass Index (BMI). Methods : With 30 adolescent girls who had never worn a brace, their Cobb angle and BMI were measured before manufacturing braces, and their corrected Cobb angle was measured after wearing the manufactured scoliosis braces. Results : The size of the major curvature before wearing the brace and the reduction rate of the curvature after putting it on had a negative correlation in both the major curvature (r=-.465, p<.01) and the minor curvature (r=-.516, p<.01). The size of the minor curvature and the reduction rate of the minor curvature before and after putting it on also had a negative correlation (r=-.429, p<.05). As for the relationship between the size of curvature and BMI, they had a negative correlation in both the major curvature (r=-.141) and the minor curvature (r=-.123), and as for the relationship between the reduction rate of curvature and BMI after wearing the brace, they had a positive correlation in both the major curvature (r=.251) and the minor curvature (r=.136); however, it was not statistically significant (p>.05). Conclusion : In conclusion, the larger the size of curvature, the lower the reduction rate of curvature after wearing the brace became. The larger the size of curvature, the lower the BMI became. The higher the BMI, the higher the correction ratio of the brace became. Therefore, it is judged that it is necessary to provide early treatment and manage body composition before scoliosis progresses.

ECG 신호의 global curvature를 이용한 ST-T 에피소드 검출 (Detection of ST-T Episode Based on the Global Curvature of Isoelectric Level in ECG)

  • 강동원;전대근;이경중;윤형로
    • 대한전기학회논문지:시스템및제어부문D
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    • 제50권4호
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    • pp.201-207
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    • 2001
  • This paper describes an automated detection algorithm of ST-T episodes using global curvature which can connect the isoelectric level in ECG and can eliminate not only the slope of ST segment, but also difference of the baseline and global curve. This above method of baseline correction is very faster than the classical baseline correction methods. The optimal values of parameters for baseline correction were found as the value having the highest detection rate of ST episode. The features as input of backpropagation Neural Network were extracted from the whole ST segment. The European ST-T database was used as training and test data. Finally, ST elevation, ST depression and normal ST were classified. The average ST episode sensitivity and predictivity were 85.42%, 80.29%, respectively. This result shows the high speed and reliability in ST episode detection. In conclusion, the proposed method showed the possibility in various applications for the Holter system.

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레이저 주사 장치의 곡률 보정에 관한 연구 (A Study on the Curvature Correction in Laser Scanner)

  • 윤남일;김남;박한규
    • 한국통신학회:학술대회논문집
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    • 한국통신학회 1986년도 추계학술발표회 논문집
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    • pp.194-197
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    • 1986
  • In this paper, for the curvature correction on the scanning plane in laser scanning system, aberration correction method using holographic optical element is suggested. Holoens is selected as a type of holographic zone plate which has aberration correction property. And hologram recording condition is analyzed to find fo property. This hololens is implemented by computer-generated hologram technique. Laser scanning system is organized using desinged hololens and scanning properties of this system are investigated. Using this method optical system structure in laser scanning system can be simplified satisfying both scan linearity and field flatness.

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Three-Dimensional Flow Analysis and Improvement of Slip Factor Model for Forward-Curved Blades Centrifugal Fan

  • Guo, En-Min;Kim, Kwang-Yong
    • Journal of Mechanical Science and Technology
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    • 제18권2호
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    • pp.302-312
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    • 2004
  • This work developed improved slip factor model and correction method to predict flow through impeller in forward-curved centrifugal fan. Both steady and unsteady three-dimensional CFD analyses were performed to validate the slip factor model and the correction method. The results show that the improved slip factor model presented in this paper could provide more accurate predictions for forward-curved centrifugal impeller than the other slip factor models since the present model takes into account the effect of blade curvature. The correction method is provided to predict mass-averaged absolute circumferential velocity at the exit of impeller by taking account of blockage effects induced by the large-scale backflow near the front plate and flow separation within blade passage. The comparison with CFD results also shows that the improved slip factor model coupled with the present correction method provides accurate predictions for mass-averaged absolute circumferential velocity at the exit of impeller near and above the flow rate of peak total pressure coefficient.

Field-Curvature Correction According to the Curvature of a CMOS Image-Sensor Using Air-Gap Optimization

  • Kwon, Jong-Hoon;Rhee, Hyug-Gyo;Ghim, Young-Sik;Lee, Yun-Woo
    • Journal of the Optical Society of Korea
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    • 제19권6호
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    • pp.658-664
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    • 2015
  • Lens designers generally refer to flat image fields and attempt to minimize the field curvature. Present-day CMOS image sensors for mobile phone cameras, however, are not flat, but curved. Sometimes it is necessary to generate an intentional field curvature according to the degree and direction of the CMOS image-sensor’s curvature. This paper presents the degree of curvature of a CMOS image sensor measured using an interferometer, and proposes an effective compensation method that minimizes the net field curvature through optimizing the air gap between lens elements, which is demonstrated using simulations and experiments.

곡률을 가진 판재의 편평도 개선을 위한 인자 연구 (A Study on the Enhancement of Flatness for the Metal Sheet with Curvature)

  • 우동욱;김지영;김정현;이상욱
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2006년도 춘계학술대회 논문집
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    • pp.273-276
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    • 2006
  • The focus of this study is on the enhancement of flatness for the shielded slot plate, one of main components of the MCFC stack. The shielded slot plate is to get curvature during manufacturing process since it is produced by forming operation from only one side of it. Therefore, a correction die is proposed to place just after the main die to apply unbending on the curved plate to get almost flat product. In the design for the correction die, four kinds of design factors are selected to study which factor is the most influencing one affecting the flatness of the plate. From the experimental results using Taguchi method, it has been revealed that the Young's modulus of urethane die is the most critical factor.

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판재 변형률 자동측정시스템의 발전 (Recent Development of Automated Strain Measurement System for Sheet Metal Parts)

  • 김형종
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2000년도 춘계학술대회논문집
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    • pp.129-133
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    • 2000
  • It is reasonable to use the stereo vision and image processing technique to digitize 3D coordinates of grid points and to evaluate surface strains on a sheet metal parts. However this method has its intrinsic problems such as the difficulty in enhancement of bad images inevitable error due to digital image resolution of camera and frame grabber unreliability of strains and thickness evaluated from coarse grid on the corner area with large curvature and the limitation of the area that can be measured at a time. Therefore it is still hard to measure strain distribution over the entire surface of a medium,- or large-sized stamped part at a time even by using an automated strain measurement system. In this study the curvature correction algorithm based on the grid refinement and the geometry assembling algorithm based on the global error minimization (GEM) scheme are suggested. Several applications are presented to show the reliability and efficiency of these algorithms.

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곡률을 가진 쉴드슬롯판의 편평도 향상 연구 (A Study on the Enhancement of Flatness for the Shield Slot Plate with Curvature)

  • 우동욱;이상욱
    • 한국기계가공학회지
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    • 제5권3호
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    • pp.23-28
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    • 2006
  • The focus of this study is placed on the enhancement of flatness for the shielded slot plate, one of main components of the MCFC stack. The shielded slot plate is to get curvature during manufacturing process since it is produced by forming operation from only one side of it. Therefore, a correction die is proposed to place just after the main die to apply unbending on the curved plate to get almost flat product. In the design for the correction die, four kinds of design factors are selected to study which factor is the most influencing one affecting the flatness of the plate. From the experimental results using Taguchi method, it has been revealed that the Young's modulus of urethane die is the most critical factor.

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