• 제목/요약/키워드: Reference Value

검색결과 2,287건 처리시간 0.039초

다양한 CAD/CAM 제조 방식으로 제작한 3본 고정성 임시 치과 보철물의 정확도 비교 (Accuracy comparison of 3-unit fixed dental provisional prostheses fabricated by different CAD/CAM manufacturing methods)

  • 이혁준;이하빈;노미준;김지환
    • 대한치과기공학회지
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    • 제45권2호
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    • pp.31-38
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    • 2023
  • Purpose: This in vitro study aimed to compare the trueness of 3-unit fixed dental provisional prostheses (FDPs) fabricated by three different additive manufacturing and subtractive manufacturing procedures. Methods: A reference model with a maxillary left second premolar and the second molar prepped and the first molar missing was scanned for the fabrication of 3-unit FDPs. An anatomically shaped 3-unit FDP was designed on computer-aided design software. 10 FDPs were fabricated by subtractive (MI group) and additive manufacturing (stereolithography: SL group, digital light processing: DL group, liquid crystal displays: LC group) methods, respectively (N=40). All FDPs were scanned and exported to the standard triangulated language file. A three-dimensional analysis program measured the discrepancy of the internal, margin, and pontic base area. As for the comparison among manufacturing procedures, the Kruskal-Wallis test and the Mann-Whitney test with Bonferroni correction were evaluated statistically. Results: Regarding the internal area, the root mean square (RMS) value of the 3-unit FDPs was the lowest in the MI group (31.79±6.39 ㎛) and the highest in the SL group (69.34±29.88 ㎛; p=0.001). In the marginal area, those of the 3-unit FDPs were the lowest in the LC group (25.39±4.36 ㎛) and the highest in the SL group (48.94±18.98 ㎛; p=0.001). In the pontic base area, those of the 3-unit FDPs were the lowest in the LC group (8.72±2.74 ㎛) and the highest in the DL group (20.75±2.03 ㎛; p=0.001). Conclusion: A statistically significant difference was observed in the RMS mean values of all the groups. However, in comparison to the subtractive manufacturing method, all measurement areas of 3-unit FDPs fabricated by three different additive manufacturing methods are within a clinically acceptable range.

탄성계수 감소곡선에 근거한 철도노반의 회복탄성계수 모델 개발 및 평가 (Development and Assessment for Resilient Modulus Prediction Model of Railroad Trackbeds Based on Modulus Reduction Curve)

  • 박철수;황선근;최찬용;목영진
    • 대한토목학회논문집
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    • 제29권2C호
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    • pp.71-79
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    • 2009
  • 본 연구에서는 국내 철도 토공노반 재료로 가장 흔히 사용되는 입도조정쇄석, 화강풍화토, 암버럭-토사 혼합 재료에 대해 평균유효주응력과 축변형률의 함수로 표현되는 회복탄성계수 예측모델을 결정하였다. 회복탄성계수 예측모델은 대표적인 동적물성치인 변형률에 따른 전단탄성계수 감소곡선의 표현과 같이 최대영탄성계수와 정규화 영탄성계수 감소곡선으로 구성된다. 평균유효주응력의 함수로 표현되는 최대영탄성계수의 모델인자는 $A_E$$n_E$이고, 비선형 영역의 정규화 영탄성계수 감소곡선은 기준변형률(${\varepsilon}_r$)과 곡률계수(a)를 모델인자로 하는 수정 쌍곡선 모델로 표현된다. 제안된 회복탄성계수 예측모델을 검증하기 위해 3차원 다층탄성해석 프로그램(GEOTRACK)을 이용하여 평택 시험 철도노반의 탄성거동을 평가하였고, 화물열차 및 여객열차가 시험구간을 통과할 때 계측한 노반의 수직 탄성변위와 비교하였다. 현장계측은 자갈도상 아래의 재료가 각각 입도조정쇄석과 양질의 화강풍화토인 두 개소에서 수행되었다. 자갈도상 아래에서 계산된 수직 탄성변위는 대략 0.6mm 이내였고 계측 결과와 잘 일치하였다. 본 연구를 통해 제안된 회복탄성계수 예측모델이 열차하중에 의한 노반의 탄성거동을 적절히 표현하고 있음을 확인하였다.

동위원소희석 ICP-MS분석법에 의한 남극 세종기지 주변 토양의 중금속 측정 (Measurement of heavy metals in antarctic soil at the king sejong station: application of isotope dilution inductively coupled plasma mass spectrometry)

  • 서정기;황의진;민형식
    • 분석과학
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    • 제21권5호
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    • pp.364-374
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    • 2008
  • 2000년도에 COMNAP/SCAR에 의해 극지지역의 환경모니터링에 관한 표준기술지침서인 'Antarctic Environmental Monitoring Handbook'이 발간되었다. 이 지침서에 따라 남극세종기지주변지역의 토양시료중의 중금속을 분석하였다. 시료분해방법은 고압산분해 방법을 사용하였고, 분석방법으로는 동위원소희석 유도결합플라스마질량분석법을 사용하여 토양중의 Pb, Cu, Zn 성분을 분석하였다. 분석방법의 정확성을 확인하기 위해 표준시료인 NIST 2702를 분석한 결과 인증값의 99.5~100.8% 범위내에서 일치하였다. Chelex 100 이온교환수지를 사용하여 간섭이온을 제거하기 위해 매질을 분리하였다. 측정결과 인위적오염이 예상되는 기지주변지역의 중금속의 평균농도는 각각 Pb 332.9 mg/kg, Cu 95.6 mg/kg, Zn 115.3 mg/kg로 나타났으며, 기지에서 멀리 떨어진 지역의 평균농도는 각각 Pb 28.1 mg/kg, Cu 101.8 mg/kg, Zn 115.6 mg/kg로 나타났다. Pb 농도는 기지주변지역과 멀리 떨어진 지점에서 현저한 차이를 보였다.

다양한 중력학적 환산방법을 적용한 한국의 합성지오이드 개발 (Development of Hybrid Geoid using the Various Gravimetric Reduction Methods in Korea)

  • 이동하;이석배;권재현;윤홍식
    • 대한토목학회논문집
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    • 제28권5D호
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    • pp.741-747
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    • 2008
  • 오늘날 미국, 일본과 같은 선진국에서는 전통적인 방법의 중력지오이드에 GPS/Leveling데이터에 의한 기하학적 지오이드를 합성한 합성지오이드를 개발하여 지오이드모델의 정확도를 높이고 있다. 따라서 하이브리드지오이드라 불리우는 합성지오이드모델을 개발하는 것이 세계적으로 지오이드모델 개발의 최신 방법이 되고 있다. 본 연구에서는 우리나라의 하이브리드지오이드 모델을 개발하기 위한 기초연구로 Remove and restore 방법에 의하여 중력지오이드를 결정하고 498점의 GPS/Leveling 데이터에 의한 기하학적 지오이드를 합성하여 우리나라의 합성지오이드모델을 개발하였다. 지구중력장모델은 EIGEN-CG03C 모델을 사용하였고 중력자료와 우리나라의 DEM을 이용하여 중력지오이드 모델을 개발하였다. 지형효과 계산을 위하여 3가지의 중력학적 환산방법(Helmert 응축 방법, RTM 방법, Airy-isostatic 방법)을 이용하여 지형효과를 산출하였고, 산출된 지형효과를 적용하여 개발되는 중력지오이드의 정확도를 분석하여 가장 적합한 중력학적 환산방법을 결정하였다. 아울러 산출된 중력지오이드에 총 498개의 GPS/Leveling 자료를 이용한 LSC 적합을 수행하여 우리나라의 수직기준에 적합한 합성지오이드를 결정하고 정확도 분석을 수행하였으며, 그 결과 RTM 환산방법을 적용하여 결정된 합성지오이드의 정확도가 $0.001{\pm}0.053m$로서 가장 높게 나타났음을 알 수 있었다.

Diversification Strategy through Market Creation: The Case of CJ Group

  • Jeong, Jaeseok;Kim, Nam Jung;Lim, Hyunjoo;Kang, Hyoung Goo;Moon, Junghoon
    • Asia Marketing Journal
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    • 제15권4호
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    • pp.1-32
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    • 2014
  • The purpose of this paper is to investigate upon a diversification strategy through market creation of CJ Group, which has contributed in positioning of the firm as one of the leading conglomerates in South Korea. With such objective, the background of CJ Group, followed by its business diversification strategies were explored, with reference to several case studies. The history of CJ Group began with establishment of CheilJedang Industrial Corporation in 1953, as the first domestic sugar producer and exporter of South Korea. The corporation gradually expanded its business ever since at both national and global level, to include the fields of food production, pharmaceutical, biotechnology, and life chemicals. Later, CheilJedang (CJ) Group was established as an affiliate of CheilJedang Industrial Corporation. With such independence, extension of business has been witnessed across the industries of media, entertainment, finance, information technology and distribution. Thus, the current CJ Group pursues to define itself as a progressive global living culture company with four major business categories from food and food service, biotechnology, entertainment and media, and logistics. Despite its success in today's market, CJ Group underwent hardships in its business diversification in 1990s due to indiscreet management, along with the Asian financial crisis. Here, many firms overcame the financial difficulties by taking advantage of the exchange rate for overseas expansion. Though, CJ Group tried to differentiate itself by focusing on the domestic market by creating something out of nothing. Hence, CJ Group takes a unique position among many cases of business diversification and their categorization. In an effort to identify and classify the types of growth experienced by the top 30 companies in South Korea, the firms were categorized into four groups according to their diversification strategies adapted after the Asian financial crisis. Based on the mode and time of entry, corporations were identified either as the 'Explorer', 'Invader', 'Venture Capitalist', or 'Assimilator'. Here, the majority of the firms showed the qualities of Invader, entering mature markets through large-scaled mergers and acquisitions. However, CJ Group was the only firm that was categorized as an Explorer, for its focus on the newly emerging service sector in culture-contents industry. This diversification strategy through market creation is worth examining, due to its contribution in generating simultaneous growth between the market and the company itself. Diverse brands of CJ Group have been referred to as case studies in this regard, from 'Hatban', 'Cine de Chef', 'VIPS' to 'CJ GLS'. These four businesses, each to represent processed food, film, restaurant service, and logistics industries respectively, show CJ Group's effectiveness in creating a whole new category of goods and services that are innovative. In fact, such businesses not only contributed in advancement of consumers' wellbeing, but toward generating additional value and employment. It is true that the diversification strategy of CJ Group requires long-term capital investment with high risk, compared to the other strategies mentioned in the paper. However, this model does create high employment and additional values that are positive to both the society and the firm itself. Therefore, the paper comes to a conclusion that the diversification strategy through market creation conveys the most positive impact relative to the others.

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The Philippines Coconut Genomics Initiatives: Updates and Opportunities for Capacity Building and Genomics Research Collaboration

  • Hayde Flandez-Galvez;Darlon V. Lantican;Anand Noel C. Manohar;Maria Luz J. Sison;Roanne R. Gardoce;Barbara L. Caoili;Alma O. Canama-Salinas;Melvin P. Dancel;Romnick A. Latina;Cris Q. Cortaga;Don Serville R. Reynoso;Michelle S. Guerrero;Susan M. Rivera;Ernesto E. Emmanuel;Cristeta Cueto;Consorcia E. Reano;Ramon L. Rivera;Don Emanuel M. Cardona;Edward Cedrick J. Fernandez ;Robert Patrick M. Cabangbang;Maria Salve C. Vasquez;Jomari C. Domingo;Reina Esther S. Caro;Alissa Carol M. Ibarra;Frenzee Kroeizha L. Pammit;Jen Daine L. Nocum;Angelica Kate G. Gumpal;Jesmar Cagayan;Ronilo M. Bajaro;Joseph P. Lagman;Cynthia R. Gulay;Noe Fernandez-Pozo;Susan R. Strickler;Lukas A. Mueller
    • 한국작물학회:학술대회논문집
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    • 한국작물학회 2022년도 추계학술대회
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    • pp.30-30
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    • 2022
  • Philippines is the second world supplier of coconut by-products. As its first major genomics project, the Philippine Genome Center program for Agriculture (PGC-Agriculture) took the challenge to sequence and assemble the whole coconut genome. The project aims to provide advance genetics tools for our collaborating coconut researchers while taking the opportunity to initiate local capacity. Combination of different NGS platforms was explored and the Philippine 'Catigan Green Dwarf' (CATD) variety was selected with the breeders to be the crop's reference genome. A high quality genome assembly of CATD was generated and used to characterize important genes of coconut towards the development of resilient and outstanding varieties especially for added high-value traits. The talk will present the significant results of the project as published in various papers including the first report of whole genome sequence of a dwarf coconut variety. Updates will include the challenges hurdled and specific applications such as gene mining for host insect resistance and screening for least damaged coconuts (thus potentially insect resistant varieties). Genome-wide DNA markers as published and genes related to coconut oil qualitative/quantitative traits will also be presented, including initial molecular/biochemical studies that support nutritional and medicinal claims. A web-based genome database is currently built for ease access and wider utility of these genomics tools. Indeed, a major milestone accomplished by the coconut genomics research team, which was facilitated with the all-out government support and strong collaboration among multidisciplinary experts and partnership with advance research institutes.

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무선국 관리의 합리적 개선방안에 관한 제안 - 무선국의 자기적합성선언 제도 도입 검토를 중심으로 - (The Proposal on the Rational Reorganization of the Radio stations Management : Focusing on the Introduction of SDoC for Radio Inspection for Telco )

  • 김호영;노원일;최성진
    • 한국전자통신학회논문지
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    • 제18권5호
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    • pp.737-746
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    • 2023
  • 전파자원은 4차 산업혁명 시대의 기술혁신을 선도하는 ICT의 핵심기반으로 경제적 가치와 활용도는 급속히 증가하고 있다. 본 연구에서는 국가의 유한자원인 전파를 이용하여 정보를 전달하는 무선국의 확산추세를 인식하고 변화하는 전파기술과 이용환경의 변화에 맞는 무선국 관리제도 개선방안 도출을 목적으로 한다. 특히, 무선국 주파수면허제 도입과 함께 무선국 준공검사를 자기적합성선언으로의 개편을 검토하는 정부계획에 기반하여 제도의 세부시행 절차와 방법을 제안하였다. 자기적합확인제도는 무선국 운용능력을 보유한 것으로 인정되는 이동통신 사업자에게 전파 혼간섭 관리의 자율성과 책임을 부여하는 정책으로 기술규제인 무선국검사 기능을 정부와 민간과 효율적으로 분산한 점에 의미가 크다. 본 연구는 전파관리제도상 사업자에 대한 자율권 부여와 책임의 명확화를 위한 규제개선 정책을 제공하는데 의의를 가진다.

연장음 길이에 따른 비유창성 정도 평가: 등간척도와 직접크기평정 비교 연구 (The perceptual judgment of sound prolongation: Equal-appearing interval and direct magnitude estimation)

  • 박진;차화정;배세진
    • 말소리와 음성과학
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    • 제15권3호
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    • pp.59-67
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    • 2023
  • 본 연구는 연장음의 길이에 따른 비유창성 지각 정도에 대해 각각 등간척도와 직접크기평정을 통한 청지각적 평가를 실시한 후, 두 평가의 결과치가 선형적인 또는 비선형적인 관계를 보이는지를 알아보고자 진행되었다. 이를 통해 연장음의 길이에 따른 비유창성 지각 정도에 대한 적절한 평가 방법을 제안하고자 하였다. 이를 위해 한국어를 모국어로 하는 만 19세 이상 성인 남녀 34명(남: 9명, 여: 25명, 평균연령: 32.9세)이 평가자로 참여였다. 실험참여자는 먼저 한국어 평마찰음 /s/를 원래 길이에서 80 ms씩 연장하여 2,000 ms(i.e., 285 ms, 365 ms., ..., 2,125 ms, 2,205 ms)까지 연장 변조한 총 25개의 자극이 들어 있는 문장을 듣고, 등간척도(1-7점, 1은 '정상', 7은 '심도')로 평가하였다. 이후에 등간척도 평가 결과, '경중도'(4점)에 해당하는 음성샘플을 선정해 이를 기준 평가치(modulus)로 하여 직접크기평정을 실시하였다. 두 평가 결과치에 대한 산포도를 작성한 후, 모형 분석을 통해 두 측정치 간의 관계가 선형적(linear)인지 비선형적(curvilinear)인지 R2값을 통해 조사하였다. 연구 결과, 두 평가 결과치의 관계가 비선형적인 양상을 보이는 것으로 나타났으며 이는 연장음의 길이에 따른 비유창성 정도 평가에 있어 등간척도보다는 직접크기평정이 적절한 평가 방법임을 보여주는 결과이다.

Detection of Contralateral Breast Cancer Using Diffusion-Weighted Magnetic Resonance Imaging in Women with Newly Diagnosed Breast Cancer: Comparison with Combined Mammography and Whole-Breast Ultrasound

  • Su Min Ha;Jung Min Chang;Su Hyun Lee;Eun Sil Kim;Soo-Yeon Kim;Yeon Soo Kim;Nariya Cho;Woo Kyung Moon
    • Korean Journal of Radiology
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    • 제22권6호
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    • pp.867-879
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    • 2021
  • Objective: To compare the screening performance of diffusion-weighted (DW) MRI and combined mammography and ultrasound (US) in detecting clinically occult contralateral breast cancer in women with newly diagnosed breast cancer. Materials and Methods: Between January 2017 and July 2018, 1148 women (mean age ± standard deviation, 53.2 ± 10.8 years) with unilateral breast cancer and no clinical abnormalities in the contralateral breast underwent 3T MRI, digital mammography, and radiologist-performed whole-breast US. In this retrospective study, three radiologists independently and blindly reviewed all DW MR images (b = 1000 s/mm2 and apparent diffusion coefficient map) of the contralateral breast and assigned a Breast Imaging Reporting and Data System category. For combined mammography and US evaluation, prospectively assessed results were used. Using histopathology or 1-year follow-up as the reference standard, cancer detection rate and the patient percentage with cancers detected among all women recommended for tissue diagnosis (positive predictive value; PPV2) were compared. Results: Of the 30 cases of clinically occult contralateral cancers (13 invasive and 17 ductal carcinoma in situ [DCIS]), DW MRI detected 23 (76.7%) cases (11 invasive and 12 DCIS), whereas combined mammography and US detected 12 (40.0%, five invasive and seven DCIS) cases. All cancers detected by combined mammography and US, except two DCIS cases, were detected by DW MRI. The cancer detection rate of DW MRI (2.0%; 95% confidence interval [CI]: 1.3%, 3.0%) was higher than that of combined mammography and US (1.0%; 95% CI: 0.5%, 1.8%; p = 0.009). DW MRI showed higher PPV2 (42.1%; 95% CI: 26.3%, 59.2%) than combined mammography and US (18.5%; 95% CI: 9.9%, 30.0%; p = 0.001). Conclusion: In women with newly diagnosed breast cancer, DW MRI detected significantly more contralateral breast cancers with fewer biopsy recommendations than combined mammography and US.

Fully Automatic Coronary Calcium Score Software Empowered by Artificial Intelligence Technology: Validation Study Using Three CT Cohorts

  • June-Goo Lee;HeeSoo Kim;Heejun Kang;Hyun Jung Koo;Joon-Won Kang;Young-Hak Kim;Dong Hyun Yang
    • Korean Journal of Radiology
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    • 제22권11호
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    • pp.1764-1776
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    • 2021
  • Objective: This study aimed to validate a deep learning-based fully automatic calcium scoring (coronary artery calcium [CAC]_auto) system using previously published cardiac computed tomography (CT) cohort data with the manually segmented coronary calcium scoring (CAC_hand) system as the reference standard. Materials and Methods: We developed the CAC_auto system using 100 co-registered, non-enhanced and contrast-enhanced CT scans. For the validation of the CAC_auto system, three previously published CT cohorts (n = 2985) were chosen to represent different clinical scenarios (i.e., 2647 asymptomatic, 220 symptomatic, 118 valve disease) and four CT models. The performance of the CAC_auto system in detecting coronary calcium was determined. The reliability of the system in measuring the Agatston score as compared with CAC_hand was also evaluated per vessel and per patient using intraclass correlation coefficients (ICCs) and Bland-Altman analysis. The agreement between CAC_auto and CAC_hand based on the cardiovascular risk stratification categories (Agatston score: 0, 1-10, 11-100, 101-400, > 400) was evaluated. Results: In 2985 patients, 6218 coronary calcium lesions were identified using CAC_hand. The per-lesion sensitivity and false-positive rate of the CAC_auto system in detecting coronary calcium were 93.3% (5800 of 6218) and 0.11 false-positive lesions per patient, respectively. The CAC_auto system, in measuring the Agatston score, yielded ICCs of 0.99 for all the vessels (left main 0.91, left anterior descending 0.99, left circumflex 0.96, right coronary 0.99). The limits of agreement between CAC_auto and CAC_hand were 1.6 ± 52.2. The linearly weighted kappa value for the Agatston score categorization was 0.94. The main causes of false-positive results were image noise (29.1%, 97/333 lesions), aortic wall calcification (25.5%, 85/333 lesions), and pericardial calcification (24.3%, 81/333 lesions). Conclusion: The atlas-based CAC_auto empowered by deep learning provided accurate calcium score measurement as compared with manual method and risk category classification, which could potentially streamline CAC imaging workflows.