• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 G
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• pp.3165-3168
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• 1999

When a input image is extensively magnified on the computer system, it is almost impossible to replicate the original shape because of mismatched coordinates system. In order to resolve the problem, the shape of the magnified image has been reconfigured using the bilinear interpolation method, low pass special filtering interpolation method and B-spline interpolation method. Ferguson curve interpolation method based on the CAD/CAM curve interpolation algorithm.

• Imaging Science in Dentistry
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• 제51권2호
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• pp.167-174
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• 2021

Purpose: Sex determination can be done by morphological analysis of different parts of the body. The mastoid region, with its anatomical location at the skull base, is ideal for sex identification. Statistical shape analysis provides a simultaneous comparison of geometric information on different shapes in terms of size and shape features. This study aimed to investigate the geometric morphometry of the inter-mastoid triangle as a tool for sex determination in the Iranian population. Materials and Methods: The coordinates of 5 landmarks on the mastoid process on the 80 cone-beam computed tomographic images(from individuals aged 17-70 years, 52.5% female) were registered and digitalized. The Cartesian x-y coordinates were acquired for all landmarks, and the shape information was extracted from the principal component scores of generalized Procrustes fit. The t-test was used to compare centroid size. Cross-validated discriminant analysis was used for sex determination. The significance level for all tests was set at 0.05. Results: There was a significant difference in the mastoid size and shape between males and females(P<0.05). The first 2 components of the Procrustes shape coordinates explained 91.3% of the shape variation between the sexes. The accuracy of the discriminant model for sex determination was 88.8%. Conclusion: The application of morphometric geometric techniques will significantly impact forensic studies by providing a comprehensive analysis of differences in biological forms. The results demonstrated that statistical shape analysis can be used as a powerful tool for sex determination based on a morphometric analysis of the inter-mastoid triangle.

• 대한치과교정학회지
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• 제50권1호
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• pp.3-12
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• 2020

Objective: This study compared three prominent midsagittal planes (MSPs) to identify the MSP that best approximates the true symmetrical MSP. Methods: Forty-three patients (mean age, 23.0 ± 8.20 years) were grouped as follows: group 1 consisted of 10 patients with skeletal Class I and a menton (Me) deviation of < 2 mm; group 2, 11 patients with skeletal Class III and a Me deviation < 2 mm; group 3, nine patients with skeletal Class III and a Me deviation of 2 to less than 4 mm; and group 4, 13 patients with skeletal Class III and an Me deviation ≥ 4 mm. The candidate MSPs were established by three-dimensional (3D) cone beam computed tomography (CBCT) reorientation methods (RMs): (1) the MSP perpendicular to the Frankfort horizontal (FH) plane while passing through the crista galli and basion; (2) the MSP including the nasion, incisive foramen, and basion; (3) the MSP including the nasion, anterior nasal spine, and posterior nasal spine. The mean absolute distances (MADs) to the MSPs were calculated from the coordinates of 1,548 points on 129 CBCT images. The differences in the values of the 3D coordinates among RMs were compared. Results: The MADs of the three RMs showed significant differences (p < 0.05). Most of the differences in values of the coordinates were not significant among RMs. Conclusions: Although the differences in distance among the three MSPs were minor, the MSP perpendicular to the FH plane while passing through the crista galli and basion best approximated the true symmetrical MSP.

• 한국산학기술학회논문지
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• 제19권4호
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• pp.593-602
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• 2018

본 논문에서는 GNSS 단일기선해석과 망조정을 통한 측량기준점 성과 산정에서 종속기선 포함여부가 미치는 영향을 분석하기 위해 망조정 이론을 바탕으로 실험적인 연구를 수행하였다. 이를 위해 국토지리정보원 운영 위성기준점 50 개소의 관측데이터를 이용하여 종속기선 포함여부에 따라 3가지 형태의 기준점 측량망 구성 및 조정실험을 수행하고, 그 결과를 정확도 표현과 산정성과의 차이 측면에서 분석 하였다. GNSS 망조정에 종속기선을 포함하는 경우 조정성과 차이는 밀리미터 수준으로 매우 제한적이었으나, 망의 자유도와 기하강도 왜곡으로 그 정확도가 과대평가되는 결과를 얻었다. 3가지 경우에 대한 조정성과를 국토지리정보원 고시좌표와 비교했으며, 그 결과 독립기선으로만 이루어진 망의 성과가 가장 높은 일치성을 보였다. 그러나 종속기선을 포함한 조정결과는 상대적으로 큰 차이를 나타내어 성과의 정확도 표현에 왜곡이 있음을 확인할 수 있었다. 이와 같은 분석결과에 따라 GNSS 단일기선해석으로 얻어진 기선벡터의 망조정에서는 기존 성과와의 일치성, 현실적인 정확도 표현 그리고 과대한 데이터 처리에 따른 시간 및 비용 부담을 고려할 때 종속기선을 제외하는 것이 타당할 것으로 판단된다.

• 대한공간정보학회지
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• 제18권4호
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• pp.31-39
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• 2010

이 연구에서는 측지 측량 분야의 GPS 사용자들이 해외 기관에서 제공하는 온라인 자료처리 서비스를 이용해 측점의 정밀좌표를 손쉽게 획득할 수 있도록 여러 기관에서 운영 중인 온라인 자료처리 서비스 간의 성능을 비교하였다. 온라인 GPS 자료처리 서비스 간의 성능비교를 위해 APPS, CSRS-PPP, AUSPOS 그리고 OPUS를 이용해 국내외 상시관측소 7곳의 좌표를 산출하였고, IERS와 국토지리정보원에서 제공하는 고시좌표와 비교하여 정확도를 분석하였다. 국외 상시관측소를 이용한 분석에서는 평균 9.3mm의 수평좌표 정확도에서 APPS, AUSPOS, OPUS, CSRS-PPP의 순서로 정확도가 높은 것으로 나타냈다. 국내 관측소의 경우 국외 분석사례와 유사하게 AUSPOS, APPS, OPUS, CSRS-PPP 순서로 높은 정확도를 보인 반면, 수평좌표 정확도는 평균 37.6mm를 기록하였다. 또한 국내 결과는 국외 결과보다 평균 3cm 큰 3차원 좌표오차를 보였으며, 북쪽 방향으로 약 3cm의 편의가 존재함을 확인하였다.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.103-105
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• 2002

Whole body stereotactic radiosurgery (WBSRS) technique is believed to be useful for the metastatic lesions as well as relatively small primary tumors in the trunk. Unlike stereotactic radiosurgery to intracranial lesion, inherent limitation on immobilization of whole body makes it difficult to achieve the reliable setup reproducibility. For this reason, it is essential to develop an objective and quantitative method of evaluating setup error for WBSRS. An evaluation technique using image registration has been developed for this purpose. Point pair image registrations with WBSRS frame coordinates were performed between two sets of CT images acquired before each treatment. Positional displacements could be determined by means of volumetric planning target volume (PTV) comparison between the reference and the registered image sets. Twenty eight sets of CT images from 19 WBSRS patients treated in Asan Medical Center have been analyzed by this method for determination of setup random error of each treatment. It is objective and clinically useful to analyze setup error quantitatively by image registration technique with WBSRS frame coordinates.

• 대한방사선치료학회지
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• 제12권1호
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• pp.20-25
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• 2000

The accuracy of the target localization was evaluated by conventional and spiral CT in stereotactic radiosurgerv. Conventional and spiral CT images were obtained with geometrical phantom, which was designed to produce exact three-dimensional coordinates of several objects within 0.1mm error range. Geometrical phantom was attached by BRW headframe, intermediate head ring, and CT localizer. Twentv-seven slices of conventional CT image were scanned at 3 mm slice thickness. Spiral CT images were scanned at 3 mm slice thickness from the pitch value 1 to 3, and twenty-seven slices of image were obtained per each the pitch value. These CT images were transferred to a treatment planning system(X-knife, Radionics) by ethernet, Three-dimensional coordinates of these images measured from the treatment planning system were compared to known values of geometrical phantom. The mean localization error of the target localization of conventional CT was 1.4mm. In case of spiral CT, the error of the target localization was within 1.6mm from the pitch value 1 to 1.3, but was more than 30mm above the pitch value 1.5. In conclusion, as the localization error of spiral CT was increased in high pitch value compared to conventional CT, the application of spiral CT will be with caution in stereotactic radiosurgery.

• 말소리와 음성과학
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• 제1권4호
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• pp.47-59
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• 2009

The purpose of this paper is to propose an automatic evaluation technique for the prosodic aspect of an English sentence uttered by Korean speakers learning English. The underlying hypothesis is that the consistency of the manual prosody scoring is reflected in an imaginary space of prosody evaluation model constructed out of the three physical properties of the prosody considered in this paper, namely: the fundamental frequency (F0) contour, the intensity contour, and the segmental durations. The evaluation proceeds first by building a prosody evaluation model for the sentence. For the creation of the model, utterances from native speakers of English and Korean learners for the target sentence are manually scored by either native teachers of English or Korean phoneticians in terms of their prosody. Multiple native utterances from the manual scoring are selected as the "model" native utterances against which all the other Korean learners' utterances as well as the model utterances themselves can be semi-automatically evaluated by comparison in terms of the three prosodic aspects [7]. Each learner utterance, when compared to the multiple model native utterances, produces multiple coordinates in a three-dimensional space of prosody evaluation, each axis of which corresponds to the three prosodic aspects. The 3D coordinates from all the comparisons form a prosody evaluation model for the particular sentence and the associated manual scores can display regions of particular scores. The model can then be used as a predictive model against which other Korean utterances of the target sentence can be evaluated. The model from a Korean phonetician appears to support the hypothesis.

• Journal of Biosystems Engineering
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• 제22권2호
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• pp.210-216
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• 1997

A study to select ground colors of Fuji apple for maturity index which are needed to standardize grading of the apples is presented. Two extreme colors of immature and fully mature Fuji and Zonagold apples produced in Korea were determined. Various ground colors of Fuji apple between the two extreme colors were collected and classified by human vision and colors of Fuji apple for maturity index were selected from the classification. Coordinates of the selected colors in xy chromaticity diagram were determined by spectrophotometers to define them in a standard coordinate system. Coordinates of the colors in r-g chromaticity diagram using a color machine vision system were also determined to use the colors in apple grading by the machine vision system. Grading Fuji apples using the machine vision system was performed and result of the grading was compared with Ending results of human vision and colorimeter. The comparison was performed with the same Fuji apple samples and showed 65% md 75% of same grades, respectively, as the grades determined by the machine vision system. Differences of fading performance between the compared three grading methods were explained as mainly because of the differences of observation area of the grading methods.

• 한국응용과학기술학회지
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• 제26권3호
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• pp.357-361
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• 2009

The authors have demonstrated white oraganic light-emitting diodes (WOLED) using 1,4-bis[2-(4'-diphenylaminobiphenyl-4-yl)vinyl]benzene as fluorescent blue emitter and iridium(III) bis(5-acetyl-2-phenylpyridinato-N,C2') acetylacetonate as phosphorescent red emitter. The optimized WOLED using red host material as bis(2-methyl-8-quinolinato) -4-phenylphenolate exhibited proper color stability in comparison with the control device using 4,4'-N,N'-dicarbazole-biphenyl as red host. The white device showed a maximum luminance of 21100 $cd/m^2$ at 14 V, luminous efficiency of 9.7 cd/A at 20 $mA/cm^2$, and Commission Internationale de I'Eclairage ($CIE_{x,y}$)coordinates of (0.32, 0.34) at 1000 $cd/m^2$. The devices also exhibited the color shift with ${\Delta}CIE_{x,y}$ coordinates of ${\pm}$ (0.01,0.01) from 100 to 20000 $cd/m^2$.