• Journal of electromagnetic engineering and science
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• 제7권3호
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• pp.134-137
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• 2007

This paper presents the design of the compact UHF Bandpass filter of CT-type with a novel mixed coupling topology. In further detail, this new coupling structure mathematically equals the transmission zero that enables particularly the better rejection performance in the stopband without increasing the filter's order. To envision this design concept, we fabricated a microstrip filter whose measurement proves to agree with the predicted performance and the suggested coupling structure reduces the overall size, and will be possibly used in the miniaturized UHF apparatus such as the RFID system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.491-494
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• 1992

This paper described the development example of optical CT(Current Transformer) and optical PT (Potential Transformer) which is measurement system of current and voltage of electric power line using Electro-Optic effect and Magneto-Optic effect. We designed the optical CT of 22KV class and 154KV class and an optical PT of 22KV class. And now the filed testing is in progress in a KEPCO's substation.

• 한국공작기계학회논문집
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• 제11권1호
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• pp.83-90
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• 2002

As high-precision parts are needed with manufacturing techniques improved. the demand of high-precision machine tools has been increasing They are made to developed the precision measuring skill to maintenance the accuracy of themselves as a matter or course We one paper measured straightness and orthogonality of the square to verify that it is possible for CT(circular test) method by 2-dimensional probe and the square to measure orthogonality Furthemore we compared the result of the study with the computer simulation's to prove its possibility and made an improvement of measuring method.

• Journal of the Optical Society of Korea
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• 제13권3호
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• pp.304-309
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• 2009

We tested the feasibility of measuring fat thickness using a miniaturized chip LED sensor module, testing 12 healthy female subjects. The module consisted of a single detector and four sources at four different source-detector distances (SD). A segmental curve-fitting procedure was applied, using an empirical algorithm obtained by Monte-Carlo simulation, and fat thicknesses were estimated. These thicknesses were compared to computed-tomography (CT) results; the correlation coefficient between CT and optical measurements was 0.932 for bicep sites. The mean percentage error between the two measurements was 13.12%. We conclude that fat thickness can be efficiently measured using the simple sensor module.

• 핵의학기술
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• 제17권1호
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• pp.11-17
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• 2013

고형암의 치료반응 평가 기준을 제시한 PERCIST에서는 제지방체중으로 표준화한 표준화 섭취계수 즉, SUL을 사용하도록 권고하고 있다. 이 연구에서는 전신 CT에서 측정된 제지방체중을 이용해 SUV를 표준화하여 얻은 SUL의 새로운 측정법을 제시하고 관찰자 사이 및 관찰자 내 재현성 여부를 평가하였다. 52명의 대상에서 전신 CT를 포함한 PET/CT를 시행하였고 -140~-30HU를 가지는 지방조직의 용적을 정확히 측정할 수 있었다. 이를 이용하여 개별 환자에서의 제지방체중을 계산하였고, 이를 이용해 SUV를 표준화하여 SUL을 측정하였다. 정상 참고 장기인 간, 복부 대동맥, 비장에 각각 지름 3 cm의 구형 VOI, $1{\times}2cm$의 원통형 VOI, 그리고 지름 2 cm의 구형 VOI를 그렸다. 경험 있는 두 명의 관찰자가 각 장기의 VOI에서 $SUL_{max}$와 $SUL_{mean}$ 을 측정하였다. 관찰자 1이 2주 간격으로 이전 측정결과를 알지 못하는 상태에서 반복 측정하였고 같은 방법으로 관찰자 2가 동일 환자에서 SUL을 측정하였다. 재현성을 평가하기 위해서 대응표본 t-test를 시행하고 Pearson의 상관계수 (CC)를 계산하였고, 측정오차를 알아보기 위해 TEM을 계산하였다. 관찰자 사이 재현성 즉, 관찰자 1과 관찰자 2가 측정한 간, 복부 대동맥, 비장의 $SUL_{max}$ 사이에는 통계적으로 유의한 차이가 없었고 이는 $SUL_{mean}$에서도 마찬가지였다. 관찰자 내 재현성 즉, 간에서 관찰자 1이 2주 간격으로 두 번 측정한 SUL 측정치 사이에도 통계적으로 유의한 차이가 없었다. 이 연구는 정상 참고 장기에서 SUL 측정이 매우 재현성이 있음을 보여준다. $SUL_{mean}$ 측정의 재현성이 $SUL_{max}$보다 약간 우수하였으며 SUL 측정치는 체중 의존성이 개선되었다. 전신 CT를 시행하여 측정한 제지방체중으로 표준화한 SUL의 새로운 측정법은 향후 여러 연구에서 유용하게 이용될 것으로 기대된다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제40권3호
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• pp.123-129
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• 2014

Objectives: The aim of this study was to verify the concordance of the measurement values when the same cephalometric analysis method was used for two-dimensional (2D) cephalometric radiography and three-dimensional computed tomography (3D CT), and to identify which 3D Frankfort horizontal (FH) plane was the most concordant with FH plane used for cephalometric radiography. Materials and Methods: Reference horizontal plane was FH plane. Palatal angle and occlusal plane angle was evaluated with FH plane. Gonial angle (GA), palatal angle, upper occlusal plane angle (UOPA), mandibular plane angle (MPA), U1 to occlusal plane angle, U1 to FH plane angle, SNA and SNB were obtained on 2D cephalmetries and reconstructed 3D CT. The values measured eight angles in 2D lateral cephalometry and reconstructed 3D CT were evaluated by intraclass correlation coefficiency (ICC). It also was evaluated to identify 3D FH plane with high degree of concordance to 2D one by studying which one in four FH planes shows the highest degree of concordance with 2D FH plane. Results: ICCs of MPA (0.752), UOPA (0.745), SNA (0.798) and SNB (0.869) were high. On the other hand, ICCs of gonial angle (0.583), palatal angle (0.287), U1 to occlusal plane (0.404), U1 to FH plane (0.617) were low respectively. Additionally GA and MPA acquired from 2D were bigger than those on 3D in all 20 patients included in this study. Concordance between one UOPA from 2D and four UOPAs from 3D CT were evaluated by ICC values. Results showed no significant difference among four FH planes defined on 3D CT. Conclusion: FH plane that can be set on 3D CT does not have difference in concordance from FH plane on lateral cephalometry. However, it is desirable to define FH plane on 3D CT with two orbitales and one porion considering the reproduction of orbitale itself.

• 한국수소및신에너지학회논문집
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• 제29권1호
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• pp.97-104
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• 2018

3-dimensional temperature distribution of the exhaust gas of a fire flame of LPG have been measured by the constructed CT-TDLAS system. 3-Dimensional temperature distributions are measured by 2 layers of CT-TDLAS. Each layer has $8{\times}8$ laser beams implying the temperatures of 64 meshes are measured. SMART algorithm has been adopted for reconstructing the absorption coefficients on the meshes. The line strengths at 6 representative wave lengths of $H_2O$ have been used for obtaining the absorption spectra of the exhaust gas. The temperature distributions measured by the constructed CT-TDLAS have been compared with those by the thermocouples. The relative errors measured between by thermocouple and CT-TDLAS were 13% in average and 33% at maximum. The similarity of temperature distribution between by thermocouples and by CT-TDLAS has been shown at the lower layer than the upper layer implying an unstability of combustions.

• 한국멀티미디어학회논문지
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• 제8권5호
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• pp.641-650
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• 2005

본 논문에서는 지오데식 동적 윤곽선 모델에서 곡선을 물체의 경계에 수렴시키기 위하여 사용되는 기존의 에지지시함수를 대신하여 CT 폐영상에서 폐실질 영역의 CT계수를 기반으로 하는 곡선제어함수를 제안하였다. 제안한 방법이 기존의 방법보다 폐실질 영역을 잘 검출할 수 있음을 세 가지 척도를 이용하여 보였다. 실제 폐영상에 적용시켜 폐실질 검출 과정과 결과를 시각적으로 관측함으로써 제안한 방법의 유효성을 검증하였다. 제안한 방법을 이용하여 실제 EBCT(electron beam computer tomography) 폐 영상에서 폐실질 영역이 정확하게 검출되었으므로 폐질환 및 국소적 폐기능 이상을 조기진단에 도움을 줄 수 있음을 확인하였다.

• 대한디지털의료영상학회논문지
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• 제12권2호
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• pp.127-132
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• 2010

In this study, the correlation among the changes of Modulation Transfer Function(MTF) in the noise and high-contrast resolution and the change of Contrast to noise ratio(CNR) in the low-contrast resolution will be examined to investigate the estimation of image quality according to the type of algorithms. The image data obtained by scanning American Association of Physicists in Medicine(AAPM) phantom was applied to each algorithm and the exposure condition of 120 kVp, 250 mAs, and then the CT number and noise were measured. The MTF curved line of the high-contrast resolution was calculated with Point Spread Function(PSF) by using the analysis program by Philips, resulting in 0.5 MTF, 0.1 MTF and 0.02 MTF respectively. The low-contrast resolution was calculated with CNR and the uniformity was measured to each algorithm. Since the measurement value for the uniformity of the equipment was below ${\pm}$ 5 HU, which is the criterion figure, it was found to belong to the normal range. As the algorithm got closer from soft to edge, the standard deviation of CT number increased, which indicates that the noise increased as well. As for MTF, 0.5 MTF, 0.1 MTF and 0.02 MTF were all sharp algorithms, and as the algorithm got closer from soft to edge, it was possible to distinguish more clearly with the naked eye. On the other hand, CNR gradually decreased, because the difference between the contrast hole CT number and the acrylic CT number was the same while the noise of hole increased.

• The Korean Journal of Pain
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• 제12권1호
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• pp.87-94
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• 1999

Backgroud: We have performed the CT-guided celiac plexus block (CPB) using anterior approach to evaluate the safety and efficacy of the procedure and to determine the role of CT. Methods: CPB were done in 10 patients (5 men and 5 women: mean age, 58.1 years) with intractable upper abdominal pain due to terminal malignancy of the stomach (n=3), pancreas (n=4), gallbladder (n=2), and liver (n=1). To permit an anterior approach, patients lay supine on the CT scan table during the procedure. One 21-guage Chiba needle was placed just anterior to the diaphragmatic crus between the celiac and superior mesenteric arteries and 10~12 ml of dehydrated alcohol was injected. Degree of pain relief following the procedure was assessed and pain was graded on a numeric rating scale (NRS) from 0 to 10. Results: The results suggest a direct relation between the degree of celiac invasion and the response to the CPB. With CT guidance, it is possible for us to direct the needle into more accurate region, allowing alcohol to be deposited in specific ganglion area. Conclusions: CT-guided CPB using an anterior approach was an easy and effective way of reducing intractable upper abdominal pain due to terminal malignancies. CT-guidance allowed precise needle placement and safe procedure. Careful classification of cases is important to predict the degree of pain relief using the grading system based on the degree of involvement of the celiac plexus.