• 대한치과의사협회지
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• 제57권12호
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• pp.747-756
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• 2019

This paper reviews the adaptation accuracy and mechanical properties of currently used denture processing systems with base resin materials and introduces the latest research on the development of antimicrobial denture base resins. Poly(methyl methacrylate) has been successfully used as a dental denture base resin material by the compress-molding method and heat polymerization for a long time, but recently, new processing techniques, injection molding-methods or fluid-resin technique are also used for fabricating denture base. However, studies indicated that there was no difference between the injectionmolding and the conventional compression-molding method in terms of adaption accuracy of denture base. The fluid-resin fabrication and one injection-molding systems exhibited better adaptation accuracy than the other processing methods. Resin denture bases in the oral cavity may undergo midline fractures due to flexural fatigue from repeated masticatory loading. For those patients, impact resistant denture base resins are recommended to prevent denture fracture during service. Thermoplastic denture base resins can be helpful for patients suffering from allergic reaction to resin monomers with a soft-fit, however, thermoplastic resins with low stiffness can irritate gum tissues and accelerate abnormal alveolar ridge resorption. Moreover, due to low chemical durability in oral cavity, those should be used for a limited period of time.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 춘계학술대회 논문요약집
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• pp.300-300
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• 2004

본 연구에서는 언어과제 수행 시 일반 공기 중의 산소 농도 (21%) 환경에 비해 외부에서 고 농도 (30%)의 산소 공급이 혈중 산소 포화도(SPO$_2$), 심박동율(Heart Rate), 정답률(Accuracy), 반응속도(Reaction Time)에 어떠한 영향을 미치는지를 검증하고자 한다. 30%와 21%의 산소를 8L/min의 양으로 일정하게 공급할 수 있는 산소 공급 장치를 이용하였고, 10명의 대학생(오른손잡이, 평균나이 23.4세)을 대상으로 실험을 수행하였다. 난이도가 비슷한 두 가지 언어과제를 28문제씩 피험자에게 풀게하여 정답률과 반응속도를 계산하였다.(중략)

• 한국전산구조공학회논문집
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• 제29권6호
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• pp.499-512
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• 2016

경계반력법은 일반적인 복합법에서 필요한 진동수영역과 시간영역의 반복 작업이 필요없는 두 단계의 시간수영역 부구조법이다. 경계반력법은 다음의 두 단계로 나누어진다: (1) 진동수영역에서 선형구간과 비선형구간 경계에서 경계반력계산, (2) 시간영역에서 경계반력을 이용한 파동방사형문제 해석. 이때 시간영역에서는 파동방사형문제를 모사하기 위해 근역지반을 모델링한다. 이 연구에서는 면진원전구조물의 비선형 SSI 해석을 위한 BRM 해석의 근역지반 모델링 범위에 따른 응답을 평가하였다. 이를 위해 등가선형 SSI 문제를 이용하여 매개변수해석을 수행하였다. BRM 응답의 정확성을 평가하기 위해 BRM 응답은 재래의 SSI 해석의 응답과 비교하였다. 수치해석결과 BRM 해석을 위한 근역지반 모델링 범위는 기초의 크기뿐만 아니라 지반조건의 영향을 받았다. 마지막으로, BRM 해석을 면진원전구조물의 비선형 SSI 해석에 적용하므로 BRM의 정확성과 효율성을 입증하였다.

• Advances in pediatric surgery
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• 제7권2호
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• pp.105-111
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• 2001

To investigate the diagnostic accuracy and applicability of barium enema(BE) and rectal suction biopsy with acetyl cholinesterase(AChE) histochemistry in the diagnosis of neonatal Hirschsprung's disease(HD), we retrospectively reviewed the findings of BE and AChE staining in 96 neonates with suspected HD during a 10-year period from January 1991 to December 2000. Sixty-nine cases of HD(58 males and 11 females) and 27 cases of non-HD are included in this study. In regard to BE, HD was based on definite transitional zone, suspicious HD on reversed rectosigmoid index(RSI <1), and non-HD on normal RSI(RSI>1). The histochemical criterion used for the diagnosis of HD was that of Chow et al(1977), i.e., the presence of many coarse discrete cholinergic nerve fibers in the muscularis mucosae and in the immediately subjacent submucosa regardless of infiltration of cholinergic nerve fibers in the lamina propria. Of 66 neonates with HD who underwent BE, transitional zone was identified in 33 cases(50 %) and reversed RSI in 19 cases(21 %), microcolon in 4 cases and normal finding in 10 cases(15 %) while of 27 neonates with non-HD, there was normal finding in 16 cases and reversed RSI in 9 cases(41 %). Thus diagnostic accuracy based on transitional zone was 64 %. The positive predictive value of reversed RSI for the diagnosis of HD was 68 %. Of 42 neonates with HD who underwent AChE histochemistry, there were 41 AChE-positive reactions and one AChE-negative reaction in a neonate with total colonic aganglionosis, while of 27 cases of non-HD, there were one equivocal AChE-positive reaction and 26 AChE-negative reactions. Thus AChE histochemical study showed a 97 % diagnostic accuracy with a 98 % sensitivity and a 96 % specificity. In conclusion, we believe that BE is valuable as a first diagnostic step since about 80 % of neonates with HD show significant radiologic findings such as a transitional zone or reversed RSI. AChE histochemical study was a more reliable diagnos tic tool showing a 97 % diagnostic accuracy, and is part.

• 한국수정란이식학회지
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• 제15권3호
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• pp.219-230
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• 2000

This study was carried out to determine the factors on achieving good viability of embryos biopsied fur sexing, to investigate pregnancy rate following embryo transfer(ET) with sexed embryos, and to confirm the accuracy for the calves bort following ET with sexed embryos by polymerase chain reaction(PCR). To investigate viability of Hanwoo embryos after biopsy for sexing, fresh and frozen/thawed embryos were biopsied according to different developmental day of blastocysts, different stage of blastocysts, and different biopsy grade and the embryos themselves were incubated for 2 hours in TCM199 after microsection to be evaluated morphologically for recovery as blastocyst. The results obtained were as follows : 1. The rate of oocytes cleaved in vitro and the rate of blastocyst of the cleaved oocytes were 52.5% and 21.6%, respectively. The rate of blastocyst on day 8 was 11.2%, denoting the highest rate during whole culture period posterior to in vitro fertilization(IVF) 2. After biopsy for sexing, the viability rate of blastocyst on day 7, 8 and 9 was 75.0%, 88.4%, and 100.0%, respectively and the viability of early, mid, and expanded blastocyst after biopsy was 75.0%, 88.9%, and 91.1%, respectively The viability rate of fresh and frozen/thawed embryos was 89.9%, 71.4%, respectively. And the viability of expanded, hatching, and hatched blastocyst of frozen/thawed embryos was : 75.0%, 75.0%, and 50.0%, respectively. The viability of embryos according to biopsy grade of 10∼20%, 21∼30%, and 31∼40% was 85.7%, 91.5%, and 71.4%, respectively. 3. Pregnancy rate after transfer with biopsied embryo between flesh and frozen/thawed embryos was 22.6% and 20.0%, respectively. 4. In comparison between sex by PCR method and sex of calves born after embryo transfer, the accuracy of sex deterimination was 92.3% (12/13).

• 분석과학
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• 제24권4호
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• pp.237-242
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• 2011

본 연구에서는 쇠고기 및 돼지고기 중 의약품인 메타미졸(metamizol)의 잔류량을 LC/MS/MS를 이용하여 정량하는 방법을 개발하였다. 분석은 그 주대사체인 4-methylaminoantipyrin (MAA)을 대상으로 하였으며, 식육에서 acetonitrile로 추출하여 간단한 정제를 거쳐 multiple reaction monitoring (MRM) 법으로 분석하였다. 정량을 위해 바탕시료에 MAA를 첨가한 식육을 추출하여 검정곡선을 작성하였다. MAA의 검량선의 결정계수는 위 두 가지의 시료에 대해 > 0.99 이었다. 개발된 시험법으로 본 실험실 내에서 6회 반복실험을 실시하였고 타 기관 두 곳에 의뢰하여 실험실간 비교 시험을 실시하였다. 쇠고기 분석의 실험실내 정확도는 78-102% (CV 5.5-9.1%), 실험실간 정확도 98% (CV 14%), 돼지고기 분석의 실험실내 정확도는 95-99% (CV 3.9-5.6%), 실험실간 정확도는 111% (CV 13%)를 보였다.

• 대한인간공학회지
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• 제26권4호
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• pp.135-142
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• 2007

Icon conveys symbolic information which they have become ubiquitous as main element of GUI. However, users often cannot intuitively understand its functional meanings. Icon has to be designed for users to easily understand functional meanings. In order to evaluate icon, the spreading activation model can be used to effectively understand the process of information retrieval. In asymmetric spreading activation model is that in the two nodes the degree of spreading activation is different according to direction. Thus, asymmetric spreading activation theory was performed evaluating the strength of association when users see visual image to associate their verbal meaning (visual image - verbal meaning pair) and users see verbal meaning to associate their visual image (verbal meaning - visual image pair). According to the direction, this study hypothesizes that the well-designed icons have symmetric relationship rather than asymmetric relationship between the two pairs. The strength of association is measured through the reaction time and the accuracy rate. In performing SAT (spreading activation test), the ten icons were selected as word processing software icons. After first SAT, newly designed icons were developed based on Korean mental model, and second SAT was conducted using them. The results showed that the accuracy rate of newly designed icon has been improved. Also there is significant difference of reaction time between current icons and newly designed icons. Well-designed icon is confirmed that the strength of association relationship arises symmetrically rather than asymmetrically between the two pairs. User centered icons could be designed by improving the strength of association between the two pairs. Asymmetric SAT evaluates the strength of the association between the visual image and the verbal meanings to contribute to the development of icon which it related to human's association structure.

• Archives of Pharmacal Research
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• 제27권7호
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• pp.720-726
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• 2004

Two Spectrophotometric procedures are presented for the determination of two commonly used H2-receptor antagonists, nizatidine (I) and ranitidine hydrochloride (II). The methods are based mainly on charge transfer complexation reaction of these drugs with either ${\rho}-chloranilic$ acid (${\rho}-CA$) or 2, 3 dichloro-5, 6-dicyanoquinone (DDQ). The produced colored products are quantified spectrophotometrically at 515 and 467 nm in chloranilic acid and 000 methods, respectively. The molar ratios for the reaction products and the optimum assay conditions were studied. The methods determine the cited drugs in concentration ranges of 20-200 and $20-160\;\mu\textrm{g}/mL$ for nizatidine and ranges of 20-240 and $20-140\;\mu\textrm{g}/mL$ for ranitidine with chloranilic acid and DDQ methods, respectively. A more detailed investigation of the complexes formed was made with respect to their composition, association constant, molar absorptivity and free energy change. The proposed procedures were successfully utilized in the determination of the drugs in pharmaceutical preparations. The standard addition method was applied by adding nizatidine and ranitidine to the previously analyzed tablets or capsules. The recovery of each drug was calculated by comparing the concentration obtained from the spiked mixtures with those of the pure drug. The results of analysis of commercial tablets and the recovery study (standard addition method) of the cited drugs suggested that there is no interference from any excipients, which are present in tablets or capsules. Statistical comparison of the results was performed with regard to accuracy and precision using student's t-test and F-ratio at 95％ confidence level. There is no significant difference between the reported and proposed methods with regard to accuracy and precision.

• 한국HCI학회논문지
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• 제14권2호
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• pp.13-20
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• 2019

산업안전을 위한 가상훈련시스템들 중 마중형 햅틱 제시 시스템에서는 가상 및 실제 물체 사이의 자연스러운 상호 작용을 위해 시각-촉각 일치가 필요하며 이를 위해 캘리브레이션이 수행된다. 본 논문에서는 어느 정도의 시각-촉각 일치를 구현한 몰입형 VR 햅틱 시스템의 사용자 평가를 수행하였다. 평가의 목표는 실제 및 가상환경에서 수행하는 일정한 과업들에 대해 두 환경에 대한 사용자 성능 (반응시간 및 거리 정확도)이 크게 다르지 않다는 것을 보이는 것이다. 사용자 평가 결과는 반응 시간에서 통계적으로 유의한 차이가 보이지만 절대 차이는 1초 미만이며 거리 정확도는 가상 환경과 실제 환경 간에 차이가 없는 것을 보여준다. 따라서 개발된 햅틱가상훈련시스템은 값비싼 실제 환경을 대신하여 저렴하게 산업안전 훈련을 할 수 있다고 사료된다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 춘계학술대회
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• pp.198-201
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• 2012

연구는 근육의 기능을 조절하는 신경말단에 전기적인 자극을 가하여 신경의 반응 정도를 측정하는 플랫폼 구현에 관란 연구로써, 전기 자극에 대한 신경반응이 가해지는 전류량, 가해진느 전류지속시간, 전극위치에 따른 반응을 측정하였다. 신경자극의 전극 위치는 표면 말단에 운동신경이면 어느 신경이든지 가능하고, 신경자극 양식에는 단순연축자극(Single Twitch Stimulation), 사연속자극(Train-of-four, TOF), 두 집단 발사자극(Double Burst Stimulation, DBS)이 있다. 임베디드 시스템기반으로 가기위한 저전력 MCU를 선정하고, 기본적인 신경자극반응 측정 센서의 민감도를 알아보기 위해 센서 인터페이스를 구성하여 반응정도를 측정해야 한다. 그리고 측정된 Data의 정확도를 높이기 위해 고성능의 AD Convertor 선정하여 플랫폼을 구현하였다. 또한 본 논문의 플랫폼은 의료기기용으로 개발되었기 때문에 시스템 이용자의 안전을 고려하여 전원회로 구성 시 전원 Isolation를 고려하여 설계하였다.