• 제목/요약/키워드: precise reproducibility

검색결과 37건 처리시간 0.024초

초음파 골밀도 측정에서 재현성 향상 방법에 관한 연구 (A Study on Method for Improving Reproducibility in the Ultrasonic Measurement of Bone Mineral Density)

  • 신정식;안중환;김화영;김형준;한승무
    • 대한기계학회논문집A
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    • 제29권10호
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    • pp.1430-1437
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    • 2005
  • It is very important to achieve a high reproducibility in the ultrasonic measurement of bone mineral density. In this study, we examined number of sampling waveform, control of temperature, diameter of region of interest as factors to improve reproducibility. We decided the optimal number of waveforms to be converted to frequency domain as period of 1. We have minimized the effects of variable temperature and constrained generation of micro bubble by keeping temperature within a range of $32\pm0.5^{\circ}C$ with a precise temperature controlling algorithm. We also found the optimal diameter of region of interest to be 13mm. In this paper, we demonstrated the improved reproducibility by controlling various factors affecting the ultrasonic measurement of bone mineral density.

사출성형기의 사출온도에 대한 측정 불확도 추정 (Measurement Uncertainty Estimation of Injection Temperature in Injection Molding Machine)

  • 정현석;유중학
    • 한국생산제조학회지
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    • 제22권1호
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    • pp.145-149
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    • 2013
  • The performance of injection molding machine's control system, such as reproducibility, repeatability, etc, is widely studied nowadays. Since screw stroke, injection cylinder body pressure and barrel temperature are the most important terms of injection unit, interval linearity and repeatability to each parameter are analyzed here. Barrel temperature is analyzed according to the repeatability of the thermocouple at $150^{\circ}C$, $210^{\circ}C$, $300^{\circ}C$ using a precise oven. The result temperature is within ${\pm}0.5^{\circ}C$ Through the reliability evaluation of the most important terms of injection unit, the method of evaluating the linearity and repeatability is proposed and verified.

초음파 변환기의 감도 교정 시스템 구성 (Design of the Calibration System for Determining the Sensitivity of Ultrasonic Transducer)

  • 사공성대;조문재;최봉열
    • 제어로봇시스템학회논문지
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    • 제5권2호
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    • pp.200-207
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    • 1999
  • In this paper, a precise sensitivity measurement system of ultrasonic transducer in the frequency range from 1 MHz to 15 MHz, which can implement the reciprocity principle is constructed. All of the elements of this system such as the ultrasonic preamplifier, ultrasonic absorber, water tank, water degassing system, and four-axes translator and reflector are constructed. For the performance evaluation of the calibration system, a standard hydrophone precisely calibrated from PTB(Physikalisch Technische Bundesanstalt) in Germany are used. And the system parameters which affected the evaluation of the measurement accuracy and the reproducibility in various measuring conditions are considered. The measurement uncertainty of the calibration system is estimated within $\pm$ 2.0㏈.

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스크류 유량계의 개발 및 정밀 성능평가에 관한 연구 (A Study on the Development and Precise Performance Test of a Screw Type Flowmeter)

  • 황종대;오지영;정윤교;이상렬
    • 한국정밀공학회지
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    • 제26권5호
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    • pp.87-95
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    • 2009
  • This research introduces the efficient modeling and manufacturing method using reverse engineering combined with rotational simulation of a pair of screw and mill-turn machining realized a proposed NC program. Because previously developed model had insufficient flow measuring accuracy, we considered that matter in the aspect of method of modeling and performance test. For that reason we modified the modeling which could minimize a gab between male and female screw, and developed precise tester which consists of constant tank, flowmeter and load cell, etc., and then conducted the test for defining characteristic and accuracy of flowmeter and repeated same test 5-times. Consequently we could obtain satisfied measuring accuracy and reproducibility indicated in the catalog of master model. Hence we give our conclusion as to the validity of developing accurate screw type flowmeter using the proposed process such as reverse engineering, mill-turn machining and precise performance test.

정위 마스크 시스템을 사용한 방사선수술시 회전중심점의 재현성 (Isocenter Reproducibility with Mask Fixation System in Stereotactic Radiosurgery)

  • 이동준;손문준;이기택;최찬영;황금철;황충진
    • 한국의학물리학회지:의학물리
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    • 제13권3호
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    • pp.135-138
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    • 2002
  • 치료대상 병소에 분할 방사선수술을 시술할 경우 회전중심(isocenter)은 정확하고 재현성 이 있어야 한다. 본 연구는 노발리스 방사선 수술장비와 정위 마스크 시스템을 사용한 분할방사선 수술에서 회전중심의 재현성을 측정하고 평가 하였다. 마스크는 열가소성 재질의 상용을 사용하였고 회전중심의 재현성을 측정하기 위해 고안된 머리 모양의 아크릴 팬텀에 맞도록 제작하였다. 팬텀의 내부에는 직경 5 mm의 아크릴봉을 수직으로 세우고 그 끝단을 회전중심으로 선택하였으며 예상되는 회전중심점에 pin hole을 낸 monochromic 필름을 설치하여 방사선 조사 후 회전중심의 재현성을 측정할 수 있도록 하였다. 측정 결과 회전중심은 공간오차가 평균 1 mm 이내이고 표준편차 또한 2 mm 이내여서 이미 보고된 타 문헌에서의 측정값과 비교해 볼 때 모든 측정값이 제시된 오차범위 내에 있었다. 결론적으로 분할방사선수술에 사용하는 정위 마스크 시스템은 매우 정확하고 재현성이 우수하였으며, 실제로 방사선 수술대상의 병소의 직경이 10 mm 정도 이상이라면 일반적인 한번의 고선량 방사선 수술에 정위 마스크 시스템의 사용이 가능할 것으로 사료된다.

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중.저기압 압력계의 국산화에 관한 연구 (A study on medium-low pressure gauge for domestic production)

  • 백용현
    • 전기의세계
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    • 제29권8호
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    • pp.519-523
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    • 1980
  • The traditional mechanical manometer is improved to develop more convenient and precise manometer in continuous measurement of the gas pressure in medium-low vacuum range (1x10$^{-1}$ -10 Torr.) Glass (solid) is used as a detector material of the improved manometer. Using the strain gauge adhered to thin glass board, mechanical strain corresponding to variation of pressure in measurement system is converted into quantity of electricity, and the quantity of electricity is amplified. Experiments have also shown that the improved manometer have more advantages in reproducibility, measured sensibility, and responsible velocity than taditional one.

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두 가지 CAD software의 맞춤형 지대주 디자인과 출력물 일치도 비교 (Comparative study of two CAD software programs on consistency between custom abutment design and the output)

  • 임현미;이규복;이완선;손큰바다
    • 구강회복응용과학지
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    • 제34권3호
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    • pp.157-166
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    • 2018
  • 목적: 두 가지 CAD software에서 각 software의 맞춤형 지대주 디자인과 출력물의 일치도를 비교 평가한다. 연구 재료 및 방법: 3Shape Dental System과Delta9 CAD 소프트웨어를 이용하여 임플란트 식립 석고모델에 맞춤형 지대주를 디자인하였다(CRM STL file).디자인한 지대주를 밀링 한 후, 접촉식 방식으로 스캔하고(Test STL file), Inspection 소프트웨어에서 각 지대주의 Test STL file과 CRM STL file을 중첩하여 오차값을 측정하였다. 결과: 시편의 전체 스캔 오차 비교와 축면 경사각에 따른 축면부위 오차비교에서 Delta9이 더 나은 밀링 재현성을 보였다(P < .05). 마진설정 시, 반경 0.9 mm에서 Delta9의 디자인과 출력물의 일치도가 더 우수했다(P < .05). 반면, Anti-rotation 형태 부여에 따른 유의할 만한 차이는 없었다. 부위별 오차 값 누적 비교에서는 Delta9이 대부분의 시편에서 더 작은 오차 값을 보였다(P < .05). 결론: Delta9이 대부분의 디자인 설정 환경에서 3Shape보다 더 작은 오차 값을 보였다. 이는 Delta9을 사용했을 때, 계획된 디자인과 출력물의 일치도가 3Shape과 유사하거나 더 좋은 출력물을 얻을 수 있음을 의미한다.

Adaptation and validation of body maps for musculoskeletal pain location in patients with severe obesity

  • Mendonca, Carolina Rodrigues;Noll, Matias;Silveira, Erika Aparecida
    • The Korean Journal of Pain
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    • 제31권4호
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    • pp.268-276
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    • 2018
  • Background: Although a variety of instruments implement body maps for the precise identification of pain symptoms, no instrument has been validated for use in people with obesity. This study reports the adaptation and validation of body maps for musculoskeletal pain location in people with obesity. Methods: Nine key anatomical regions were highlighted based on the original images of the Nordic Musculoskeletal Questionnaire body maps. Adult silhouettes were generated from photographs of men and women with obesity. The body dimensions were adjusted to take into account the different body fat distribution patterns of people with obesity. The validity of the images was assessed by 12 experts. Subsequently, a data collection stage was performed with 58 patients with severe obesity from both sexes. The reproducibility of the images was tested by comparison with the original images. Results: The results of the validation pilot study indicated that the adapted images facilitated the location of musculoskeletal pain in men and women with obesity. The reproducibility of the original and adapted versions of the body maps indicated good agreement for pain over the last 12 months and 7 days (80% vs. 79.7%). Pain scores in the last 12 months indicated good and high sensitivity and specificity for all body areas (60.9% vs. 89.1%). Considering pain in the last 7 days, high sensitivity and specificity for all areas of the body (85.1% vs. 70.1%). Conclusions: The body maps developed in this study are reliable and valid to identify the location of pain in people with obesity.

치아크기 계측오차에 관한 연구 (A study on the error of tooth size measurements)

  • 심은주;황현식;문재동
    • 대한치과교정학회지
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    • 제29권4호
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    • pp.491-501
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    • 1999
  • 본 연구는 석고모형 분석 중 치아크기 측정시 발생할 수 있는 오차를 줄이고 측정의 재현도와 정확성을 향상시키는데 도움이 될 수 있는 방안을 모색하고자 시행되었다. 치아밀집 치열 특징을 지닌 상하악 20조의 석고모형을 대상으로 하여, 5명의 조사자가 각 치아의 근원심 폭경을 디지털 버니어 캘리퍼스를 사용하여 2주 간격으로 3회 측정하여 실험측정치를 얻은 다음, 측정에 이용된 석고모형을 근원심 접촉점 부위에서 개개 치아로 분리한 후, 마이크로미터를 이용하여 측정한 표준치와 비교$\cdot$분석하여 다음과 같은 결과를 얻었다. 1. 3회 측정에 따른 재현도는 조사자별 치아별로 큰 차이를 나타내지 않았다. 2. 표준치와 비교한 계측오차는 조사자별 또는 치아별로 차이를 보였다. 3. 표준치와의 오차는 전치에서 구치로 갈수록 증가하여 제1대구치에서 가장 큰 차이를 나타내었다. 4. 표준치와 비교시 전반적으로 작게 측정하는 경향을 보였으며 이에 대한 치아별, 조사자별 차이가 두드러졌다. 5. 전반적인 오차 발생 정도는 치아밀집 정도와 유의한 상관성을 보이지 않았다. 이상의 결과는 교정증례 분석시 치아크기 계측오차 발생 가능성의 고려가 필요함을 시사하였다.

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총 IgE의 신속한 정량 측정을 위한 ImmuneCheck IgE의 임상적 유용성 (Clinical validation of ImmuneCheck IgE for the rapid detection of serum total IgE)

  • 이신행;최진영;최은주;이상철;박경희;이재현;박중원
    • Allergy, Asthma & Respiratory Disease
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    • 제6권6호
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    • pp.310-314
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    • 2018
  • Purpose: Conventional serum IgE assay was costly, required the skills of expert, and relied heavily on expensive equipment. Quantitative measurement of total IgE using Point of Care Test (POCT) device can be the solution for these limitations. This study evaluated and validated the reproducibility of ImmuneCheck IgE. Methods: This study included 120 patients of allergic diseases such as allergic rhinitis, asthma, drug allergy, food allergy, atopic dermatitis, or anaphylaxis. The reliability of POCT ImmuneCheck IgE was evaluated by comparing results from the naked eye and from the Q-Reader. Intratest reproducibility and intertest correlation were analyzed using intraclass correlation coefficient (ICC). Results: Of the 120 enrolled patients, 51 were males and 69 were females. The ages ranged from 19 to 84 years, with an average age of 51.5 years. The concentration of serum total IgE measured by Phadia ImmunoCAP IgE ranged from 5.95 to 5,000 IU/mL. ICC for Intratest reproducibility of ImmuneCheck IgE by naked eye and by Q-Reader were 0.991 (P< 0.001) and 0.989 (P< 0.001), respectively. In addition, intertest correlation between ImmuneCheck IgE and Phadia ImmunoCAP IgE results of naked eye and Q-Reader were 0.968 (P< 0.001) and 0.948 (P< 0.001), respectively. Conclusion: The ImmuneCheck IgE was reproducible and highly correlated with conventional Phadia ImmunoCAP IgE assay. This result suggests that ImmuneCheck IgE can be a useful tool for rapid and precise detection of total IgE.