• 대한화학회지
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• 제67권2호
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• pp.106-115
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• 2023

이 연구의 목적은 전국과학전람회에서 장려상을 수상한 학생의 과학탐구 연구보고서 오류를 조사하고, 학교급별 오류 유형 빈도를 분석하는 것이다. 학생 과학탐구 연구보고서 목차를 바탕으로 분석틀을 구성하고 연구 문제/가설, 선행연구, 실험 수행, 결과, 결론, 참고문헌 6단계로 나누어 오류를 분석하였다. 연구 문제/가설에서 '잘못된 연구 문제 설정', '잘못된 가설' 실험 수행에서 '변인 설정 오류', '제한된 조건만 고려', '측정의 오류', '실험기구 부정확한 사용', '기구 및 재료 선택의 오류', '불충분한 실험 회수'등 각 단계별로 여러 유형의 오류를 확인하였다. 연구결과, 실험 수행은 모든 학교급에서 오류 비율이 가장 높았으며, 실험 수행을 제외한 오류 유형의 비율은 학교급별로 차이가 있었다. 학교급별 오류 유형 비율은 초등학생은 실험 수행(36.88%), 선행연구(17.02%), 결론(16.31%), 연구 문제/가설(13.48%), 중학생은 실험 수행(42.86%), 결론(20.00%), 선행연구(14.28%), 결과(11.43%), 연구 문제/가설(10.01%), 고등학생은 실험 수행(45.16%), 연구 문제/가설(16.13%), 결론(16.13%), 선행연구(11.83%) 순으로 나타났다. 이 연구 결과는 교사가 학생 과학탐구 연구 및 보고서 작성을 지도할 때 지도계획을 수립하는데 활용할 수 있을 것으로 기대된다.

• Advances in pediatric surgery
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• 제4권2호
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• pp.100-109
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• 1998

The anomalous pancreaticobiliary duct union (APBDU) might cause the formation of choledochal cyst and malignancies of hepatopancreaticobiliary system. The purpose of this study is to make an experimental animal model of APBDU similar to that of human. One to two-month-old Mongrel dogs (n=12) were divided into two groups; the control group (n=2) had a sham operation performed, and in the experimental group (n=10) the end of distal ' common bile duct (CBD) was anastomosed to the side of the dorsal pancreatic duct making APBDD. Serum was obtained for chemical analysis on the 10th postoperative day. The dogs were sacrificed at the 5th week (n=3), the 6th week (n=3), the 7th week (n=2), the 8th week (n=2) and the 6th month (n=2) after the experimental surgery. With sacrifice, operative cholangiogram was taken, and bile juice was obtained for chemistry and bacterial culture. The en-bloc specimens of the hepatopancreaticobiliary system were removed for microscopic examination. Serum and bile juice amylase levels were elevated in the experimental group(n=10), but not in the control group(n=2). Operative cholangiograms of control group revealed no evidence of bile duct dilatation.. On the other hand, the bile duct in the experimental group was markedly dilated without any evidence of stenosis at the anastomosis site (n=10). Histologic examination of the hepatopancreaticobiliary system in the experimental group resembled the findings of choledochal cyst in human. The APBDU of this animal model can produce bile duct dilatation by pancreaticobiliary reflux. We think that this animal model can be potentially promising for the research about the APBDU associated hepatopancreaticobiliary diseases.

• 방송공학회논문지
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• 제16권3호
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• pp.471-482
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• 2011

본 논문에서는 실험방송용으로 개발된 고화질 3DTV 실험방송 시스템 및 이의 성능 분석 결과에 대해 소개한다. 2010년 말에 성공적으로 실시된 고화질 3DTV 실험방송은 지상파, 케이블, 위성 3개의 방송매체를 대상으로 하고 있으며, 역방향 호환성을 보장하면서 고화질의 입체감 제공을 위해 듀얼스트림 방식을 채택하고 있다. 듀얼스트림 방식은 MPEG-2 시스템의 다중화 기술을 응용한 것으로서, 특히 지상파 방송의 경우 좌영상 인코딩은 기존의 비디오 코덱을 그대로 사용하고 동시에 우영상 인코딩은 효율이 향상된 비디오 코덱 기법을 사용하고 있다. 본 논문에는 고화질 3DTV 실험방송을 실시하기 위해 개발된 송수신 시스템의 구현 방법을 3DTV 재다중화기 및 수신기 위주로 기술하며, 마지막으로 시스템의 구현결과 및 지상파 3DTV 실험방송 실시 결과에 대해 객관적 및 주관적인 평가를 통해 검증한다.

• Journal of Periodontal and Implant Science
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• 제34권1호
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• pp.177-193
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• 2004

Several experimental studies showed that the application of small amounts of electric current to bone stimulated osteogenesis at the site of the cathode and suggested that electrical currents promote osseointegration around dental implants. The purpose of this study was to determine the effect of direct microcurrent to endosseous titanium implants placed in bone defects. The right and left 2nd, 3rd and 4th mandibular premolars in ten mongrel dogs (15Kg of weight) were extracted. One monthe later, Ti-machined screw type implants(3.8 mm diameter x 8.5 mm length, $AVANA^{(R)}$, Ostem) were placed in surgically created circumferential defect area(width 5mm, depth 4mm). The implants were divided into three groups according to the treatment modalities: Control group- implants without electrical stimulation; Experimental group I- implants with allogenic demineralized freeze dried bone grafting; and Experimental group II-implants allogenic demineralized freeze dried bone grafting and electric stimulation. The animals were sacrificed in the 4th and 8th week after implant placement and un-decalcified specimens were prepared for histological and histometrical evaluation of bone-implant contact ratio (BIC) and bone formation area ratio (BFA) in defect area. Some specimens at 8 weeks after implantation were used for removal torque testing. Histologically, there was connective tissue infiltration in the coronal part of defect area in control and the experimental group I, whereas direct bone contact was found in the experimental group II without connective tissue invasion. Average BIC ratios at 4 weeks of healing were 60.1% in the experimental group II, 47.4% in the experimental group I and 42.7% in the control. Average BIC ratios at 8 weeks after implantation were 67.6% in the experimental group II, 55.9% in the experimental group I and 54.6% in the control. The average BFA ratio was 84.0% in the experimental group II, 71.8% in the experimental group I and 58.8% in the control at 4 weeks, and the BFA ratios were 89.6% in the experimental group II, 81.4% in the experimental group I and 70.5% in the control at 8 weeks after implantation. The experimental group II showed also significantly greater BIC and BFA ratios compared to the control and the experimental group I (p<0.05). The removal torque values at 8 weeks after implantation were 56 Ncm in the experimental group II, 49 Ncm in the experimental group I and 43 Ncm in the control. There was a statistically significant difference among 3 groups (p<0.05). These results suggest that electrical stimulation improve and accelerate bone healing around endosseous titanium implants in bone defect.

• 한국한의학연구원논문집
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• 제1권1호
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• pp.69-99
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• 1995

In order to develop experimental research in oriental medicine, it is necessary to make experimental model of diagnostic pattern(證), On model of the condition of a disease maked in china, there are cold-pattern(寒證), heat-pattern(熱證), deficiency of vital energy-pattern(氣虛證), blood-deficiency-pattern(血虛證), yin-deficiency-pattern(陰虛證), yang-deficiency-pattern(陽虛證), deficiency of both yin and yang-pattern(陰陽俱虛證), yang-exhaustion-pattern(亡陽證), blood stasis-pattern(血瘀證), pattern of defferential diagnosis according to states of viscera(臟腑辨證).

• Structural Engineering and Mechanics
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• 제12권2호
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• pp.119-134
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• 2001

This paper deals with an experimental and numerical study of a mono-strand wedge anchor head mechanism. First, the experimental program is presented and monitored data such as wedge slippage, anchor deflection and strain distributions along external peripheral surfaces of the anchor head are presented and discussed. In accordance with the experimental set up, these data concern only the global behaviour of the mechanism and cannot provide valuable information such as internal stress-strains distributions, stress concentrations and percentage of yielded volume. Therefore, the second part of this paper deals with the development of an efficient numerical finite element model capable of providing mechanism of the core information. The numerical model which includes all kinematics/material/contact non-linearities is first calibrated using experimental data. Subsequently, a numerical study of the anchorage mechanism is performed and its behaviour is compared to the behaviour of a slightly geometrically modified mechanism where the external diameter has been increased by 5 mm. Finally, different topics influencing the anchorage mechanism behaviour are addressed such as lubrication and wedge shape.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.17-17
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• 1996

An experimental research is a useful approach for realizing autonomous mobile robots to work in real environment. We are developing an autonomous mobile robot platform named "Yamabico" as a tool for experimental real world robotics research. The architecture of Yamabico is based on the concept of centralized decision making and functionally modularization. Yamabico robot has two level structure with behavior and function levels, and its hardware and software are functionally distributed for providing incremental development and good maintenancibility. We are using many Yamabico robots in our laboratory to realize the robust navigation technology for autonomous robots. The methodology for experimental and task-oriented approach of mobile robotics will be presented. And some experimental results of real world navigation in indoor and outdoor environment will be shown. be shown.

• 품질경영학회지
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• 제15권2호
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• pp.69-73
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• 1987

The aim of this study is to find out the optimal goods for the marketing research through analysing the factor effecting the marketing survey by using the experimental design method. The decisive effecting factors in relation with the marketing survey were investigated as follows; 1. A row effect (Ai; i = 1, 2, ... n) is the design sorts of woman-clothes bias. 2. A column effect (Bi; i = 1, 2, ... n) is the woman-consumer bias. In this paper the experimental design, execution and statistical analys is were conducted to find out the optimal goods for marketing research.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2002년도 Current Trends in Toxicological Sciences
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• pp.74-74
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• 2002

Ethyl 3-(4'-geranyloxy-3-methoxyphenyl)-2-propenoate (EGMP) and ferulic acid (FA) have been shown to inhibit development of aberrant crypt foci (ACF) in the azoxymethane (AOM)-treated rat colon. In the present study, inhibitory effects of EGMP and FA on the post-initiation stage of AOM-induced colon carcinogenesis were studied in male ddY mice.(omitted)

• Structural Engineering and Mechanics
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• 제50권2호
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• pp.231-240
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• 2014

In the present research, fatigue behavior of chopped strand mat/epoxy composites has been studied with two different techniques. First, the normalized stiffness degradation approach as a well-known model for unidirectional and laminated composites was utilized to predict the fatigue behavior of chopped strand mat/epoxy composites. Then, the capability of the fatigue damage accumulation model for chopped strand mat/epoxy composites was investigated. A series of tests has been performed at different stress levels to evaluate both models with the obtained results. The results of evaluation indicate a better correlation of the normalized stiffness degradation technique with experimental results in comparison with the fatigue damage accumulation model.