• Restorative Dentistry and Endodontics
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• 제20권2호
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• pp.812-817
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• 1995

Endodontically treated teeth are usually restored for crown protection, aesthetics, and prevention of root canal recontamination. Restoration of these teeth, however, often requires intracanal posts. Various depths and techniques have been recommended for the preparation of post space. Therefore the purpose of this study was to evaluate the effect that pst preparation has on the coronal seal by linear dye penetration of root canals obturated by lateral condensation, vertical condensation, and thermafil techniques. Forty canals of roots of incisors and canines were cleaned and shaped with the use of a step-back technique. Thirty canals were obturated, 10 each with lateral, vertical, and thermafil techhniques. Five root canals were obturated without a root canal sealer and served as positive controls. Another five root canals were obturated, and their coronal half was sealed with sticky wax and served as negative controls. The apical 5 to 6mm of the filling materials were exposed to india ink for 48 hours. The depth of dye penetration was measured in all groups and statistically analyzed (ANOVA). The results were as follows. 1. The apical plugs in the thermafil groups had the highest degree of coronal dye leakage. 2. The group filled by vertical condensation technique had the lowest degree of coronal dye leakage. 3. No significant statistical difference was found in the amount of coronal dye leakage in canals filled by lateral condensation versus those filled by the veritcal condensation technique. 4. Significant statistical differences in coronal dye penetration were found between the canals filled by thermafil and those filled by the lateral or vertical condensation techniques (p<0.05).

• 대한기계학회논문집A
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• 제41권3호
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• pp.181-186
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• 2017

점진 판재 성형은 금형을 제작하지 않고 판재를 가공하는 방법으로써 빠른 시제품 제작과 소량 생산에 적합한 성형법이다. 이러한 점진 판재 성형의 공정 변수로 공구 직경, 매 스탭당 z-방향 깊이, 공구 이송속도, 공구 회전 속도 등은 성형품의 품질에 크게 영향을 미친다. 본 연구에서는 Al5052-O(0.8mm) 판재를 사용하여 Varying Wall Angle Conical Frustum 모델의 점진성형을 실시하였으며, 각각의 변수들의 조합에서 성형성을 판단하였다. 다구찌 기법을 사용하여 점진성형 변수들의 조합을 찾아내고, 그레이 관계형 최적화를 통하여 최적 성형 변수 값의 조합을 찾아 내였다. 최종 성형물의 품질은 성형성, 스프링 백, 두께 감소량을 측정하여 판단하였다. 본 연구의 실험 조건에서의 최적의 변수 조합은 공구직경 6 mm, 회전속도 60rpm, 매 스탭당 z-방향 깊이 0.3 mm, 이송속도 500 mm/min으로 판단되었다.

• 한국산학기술학회논문지
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• 제10권2호
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• pp.320-326
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• 2009

자동차 운전에 있어 운전자의 시야확보는 안전운행을 위한 가장 중요한 요소 중에 하나이다. 따라서 빠른 시간 안에 자동차 전후방에서 펼쳐지는 상황을 파악하는 일이 안전운전의 첫걸음이다. 특히, 사고 발생률 대비 치사율이 가장 높은 안개가 자주 발생하는 지역에서의 시야확보는 필수적이다. 본 논문에서는 GPS를 이용하여 차량내부에 설치되어 있는 임베디드 보드 네비게이션 모니터링 시스템을 통해 다른 차량의 위치를 실시간으로 보여줌으로써 운전자의 시야확보를 제공한다. 본 시스템을 이용하여 안전운행을 할 수 있고 갑자기 일어나는 돌발 상황에 대처하여 추돌사고의 확률을 낮출 수 있다.

• International Journal of Contents
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• 제7권1호
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• pp.14-22
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• 2011

Temporal Sign Language Recognition (TSLR) from hand motion is an active area of gesture recognition research in facilitating efficient communication with deaf people. TSLR systems consist of two stages: a motion sensing step which extracts useful features from signers' motion and a classification process which classifies these features as a performed sign. This work focuses on two of the research problems, namely unknown time varying signal of sign languages in feature extraction stage and computing complexity and time consumption in classification stage due to a very large sign sequences database. In this paper, we propose a combination of Dynamic Time Warping (DTW) and application of the Single hidden Layer Feedforward Neural networks (SLFNs) trained by Extreme Learning Machine (ELM) to cope the limitations. DTW has several advantages over other approaches in that it can align the length of the time series data to a same prior size, while ELM is a useful technique for classifying these warped features. Our experiment demonstrates the efficiency of the proposed method with the recognition accuracy up to 98.67%. The proposed approach can be generalized to more detailed measurements so as to recognize hand gestures, body motion and facial expression.

• 한국멀티미디어학회논문지
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• 제5권5호
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• pp.505-514
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• 2002

본 논문에서는 내용기반 영상 분류를 위한 방법론으로써 신경망을 이용한 방법을 제안한다. 분류 대상 영상은 인터넷상의 다양한 영상들 중에서 전경과 배경의 구분이 있는 객체 영상이다. 전처리 과정에서 영역 분할을 이용하여 영상 내에서 배경을 제거하고 객체 영역을 추출한다. 분류를 위한 특징은 웨이블릿 변환 후 푸출된 형태 특징과 질감특징을 이용한다 추출된 특징 값들을 이용하여 영상들에 대한 학습패턴을 생성하고 신경망 분류기를 구성 한다. 신경망의 학습 알고리즘은 역전파 알고리즘을 사용한다. 가장 효과적인 질감특징을 선 택 하기 위한 실험에서는 대각 모멘트가 가장 높은 분류률을 보여 주었다. 배경을 제거 하고 대각 모멘트를 특징으로 사용하여 실험하였을 때, 30종류에서 각 10개씩 총 300개의 학습 데이터와300개의 테스트 데이터에 대하여 각각 72.3%와 67%의 정분류률을 보였다.

• Nuclear Engineering and Technology
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• 제35권2호
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• pp.165-170
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• 2003

We developed an improved 3-PM liquid scintillation counting (3-PM LSC) method in which three detectors can be displaced to back and forth directions, and a data acquisition system being able to provide the values for all parameters required for the method. The detectors are entirely located in a 20-mm lead chamber of an inner diameter of 500 mm. A saw-toothed gear ties up all detectors so as to move them uniformly, up to 50 mm with unit of 1 mm. The data acquisition system was designed in an integrated circuit to perform the necessary works such as fast amplification, discrimination, coincidence and logic analysis. It generates values of nine parameters among twelve's generated in the 3-PH LSC method. The dead time of each counting channel is of extending type, valving from 10 to 100 $mutextrm{s}$. We measured the TDCR values with an unquenched liquid scintillation source 1"C by displacing the detectors with a step of 2.5 mm away from counting vial. Their values were derived on the range from 0.9 to 0.6. The extent is three times wider than those regions observed by applying the defocalization technique.ique.

• 한국도서관정보학회지
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• 제26권
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• pp.365-400
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• 1997

The interface design for most present query-base model of OPAC systems does not include the function to implement an iterative feedback process till the user arrives at satisfied search results through the interaction with the system. Also, the interface doesn't provide the help function for a user to select pertinent search terms. To formulate a query at the present OPAC system, a user should learn a set of syntax different from system to system. All of above mentioned things make an end-user feel difficult to utilize an OPAC system effectively. This experimental system is attempted to alleviate a few limitations of the present OPAC system by a n.0, pplying the direct-manipulation technique as well as the feedback principle. First, this system makes it unnecessary for a user to learn some syntax for query formulation by providing option buttons for access points. Second, this system makes it possible for a user to decide whether each displayed record is relevant or not, and for keywords included in the relevant records to be automatically stored in order to be used for later feedback. Third, in this system, the keywords stored in [sayongja yongeu bogyanham] can be deleted if unnecessary or can selected as search terms for a query expansion as well as a query modification. Fourth, in this system, after inputting the original query, the feedback process can be proceed without coming back to the previous search step until a user becomes satisfied with the search results. In conclusion, the searching behaviors of heterogeneous users should be continuously observed, analysed, and studied, the findings of which should be integrated into the design for the interface of the OPAC system.

• Restorative Dentistry and Endodontics
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• 제22권2호
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• pp.596-608
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• 1997

The purpose of this study was to compare the apical leakage and adaptation to the dentinal wall of a glass ionomer root canal cement(Ketac-Endo) with those of AH-26 and Tubli-Seal. 102 single-rooted teeth were insrumented with step-back technique and randomly divided into four groups according to kinds of root canal cements: Ketac-Endo, AH-26, Tubli-Seal, and no root canal cement. Four experimental groups were as follows; Group 1 : Filling with gutta-percha and Ketac-Endo Group 2 : Filling with gutta-percha and AH-26 Group 3 : Filling with gutta-percha and Tubli-Seal Group 4 : Filling with gutta-percha without root canal cement All the specimens were obturated with lateral condensation technique, and stored in 100% humidity for 4 days. 20 teeth in each group were placed in centrifuge tube filled with India ink, and then centrifuged for 20 minutes at 3,000 rpm. And they were evaluated for linear dye leakage using a stereoscope and analyzed by one-way ANOVA. 22 teeth were split longitudinally and evaluated the adaptation to the dentinal wall using scanning electron microscope(4 teeth in each group) and stereoscope(2 teeth in 1, 2, 3 group). The obtained results were as follows ; 1. In case of not used root canal cement(Group 4), there was showed much degree of dye penetration comparerd with used root canal cements (Group 1, 2, 3)(P<0.01). 2. In the case of used root canal cements(Group 1, 2, 3), there was no significant difference in linear leakage in groups(P>0.01). 3. In the case of used root canal cements(Group 1, 2, 3), there was showed intimate adaptation to the dentinal wall independent on kinds of root canal cements. 4. Fractured surfaces indicated failure of cohesion in Ketac-Endo, and failure of adhesion to dentine in AH-26 and Tubli-Seal. 5. According to similar apical leakage and adaptability to the dentinal wall to another root canal cements, it is possible to be used glass-ionomer cement as root canal cement.

• Restorative Dentistry and Endodontics
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• 제22권2호
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• pp.648-658
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• 1997

The purpose of this study was to compare the effects of various techniques on the quality and quantity of instrumentation in curved canals. Instrumentation time was evaluated too. Forty eight canals of resin blocks($35^{\circ}$) were divided into three groups and filed. In group A, 16 blocks were instrumented using a step-back technique with stainless steel(SS) K-file(Mani, Matsutani Seisakusho Co.,Japan). In group B, canals were prepared with SS K-files using the Endo-Angle (Nakanishi Dental MFG.CO.,LTD.,Japan). Group C was prepared using N i-Ti engine-driven instruments (Quantec Series $2000^{TM}$ system). Group A and B were filed from # 5 to # 25 at the apex followed by a 1 mm stepback technique, and the coronal half of the canals were flared with Gates Glidden burs(#2,3,4). Group C was instrumented from # 1 to # 8. After the instrumentation time was measured, canals were filled with India ink, and photographed, which to magnify the canal images 8 times. Using these photographs the apical portions were evaluated And scored from 1 to 4 according to the severity of ledging and zipping. On the same photographs, the area of the coronal two thirds of the canals were measured using a personal computer with the computer program Brain and Digitizer (SummaSketch III). The following results were obtained. 1. Instrumentation time was significantly shorter for group C, as opposed to group A and B(ANOVA, P<0.05). 2. The qualitative evaluation of the apical portions of the canals showed no significant difference between the groups(Kruscal-Wallis, p>0.05). 3. The area removed by group C was significantly smaller than group A and B(ANOVA, P<0.05).

• 경영과정보연구
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• 제22권
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• pp.211-229
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• 2007

The ISO/TS16949 APQP goal of defect prevention and decrease of spread waste, is the customer satisfaction which leads a continuous improvement and profit creation. The quality expense where the most is caused by but with increase of production initial quality problem occurrence is increasing to is actuality. Like this confirmation amendment. with the problem which is forecast in the place development at the initial stage which it does completeness it does not confront not to be able, production phase to be imminent, the problem accumulates and it talks the development shedding of which occurs. In opposition, prediction confrontation. is forecast in development early stage to and it is a structure which does not occur a problem to production early stage. Like this development is a possibility of accomplishing competitive company from production phase. Which attains an goal of, chance cause it leads a APQP activity (common cause) with special cause prevention & detection the connection characteristic of the focus technique against a interaction is important. And the customer requirement satisfaction and must convert a APQP goal of attainment at the key characteristics action step. (1) The Prevention - with Design FMEA application prevention of the present design management/detection, (2) the Detection (prevention/detection) - with Process FMEA application prevention of the present process control/detection, (3) Special Cause - statistical process control (SPC) 4M cause spread removal, (4) Common Cause - statistical process control (SPC) the nothing zero defect which leads the continuous improvement back of spread with application it will be able to attain with application.