Formulation of a reference coordinate system of threedimensional head & neck images : Part Ⅱ. Reproducibitity Ⅱ부 수평기준면과 정중사상면의 재현성

Kim, Nam-Kug,Park, Jae-Woo,Chang, Young-Il 대한치과교정학회 발행 2005 대한치과교정학회지 Vol.35 No.6

This study was performed to investigate the reproducibility of the horizontal and midsagittal planes, and to suggest a stable coordinate system for three-dimensional (3D) cephalometric analysis. Eighteen CT scans were taken and the coordinate system was established using 7 reference points marked by a volume model, with no more than 4 points on the same plane. The 3D landmarks were selected on V works (Cybermed Inc., Seoul, Korea), then exported to V surgery (Cybermed Inc., Seoul, Korea) to calculate the coordinate values. All the landmarks were taken twice with a lapse of 2 weeks. The horizontal and midsagittal planes were constructed and its reproducibility was evaluated. There was no significant difference in the reproducibility of the horizontal reference planes. But, FH planes were more reproducible than other horizontal planes. FH planes showed no difference between the planes constructed with 3 out of 4 points. The angle of infersection made by 2 FH planes, composed of both Po and one Or showed less than 1° difference. This was identical when 2 FH planes were composed of both Or and one Po. But, the latter cases showed a significantly smaller error. The reproducibility of the midsagittal plane was reliable with an error range of 0.61 to 1.93° except for 5 establishments (FMS-Nc, Na-Rh, Na-ANS, Rh-ANS, and FR-PNS). The 3D coordinate system may be constructed with 3 planes; the horizontal plane constructed by both Po and right Or; the midsagittal plane perpendicular to the horizontal plane, including the midpoint of the Foramen Spinosum and Nc; and coronal plane perpendicular to the horizontal and midsagittal planes, including point clinodale, or sella, or PNS. 본연구는 삼차원 두부 영상을 위치시키기 위한 좌표계를 구성하는 방법에 대한 제안하기 위해, CT data에서 기존의 두부방사선 계측사진에서 쓰이는 점들을 선정하고, 이를 바탕으로 수평, 수직평면의 안정성을 조사하였다. 서울대학교 치과병원에 내원한 환자 18명의 CT자료를 채득하였으며, 모든 환자는 서울대학교 병원 진단방사선과에서 촬영하였다. (Somatom Plus 4: Siemens, Eriange, Germany). V works for surgery 4.0 (Cybermed Inc., Seoul, Korea)을 이용하여 3차원 좌측표를 선정하고, 계측점을 선택하였다. 좌표축을 동일하게 설정하기 위해 7개의 점(reference point)을 4·4·2 pixel size의 voxel로 따로 표시하였다. 계측점을 선정한 후 V surgery (Cybermed Inc., Seoul, Korea)에서 각 점의 좌표값을 추출하였다. 각각의 점들은 2회 반복 선정한 후 점들을 조합하여 수평, 수직평면의 재현성을 평가한 결과 다음과 같은 결론을 얻었다 수평 기준면의 재현도는 S-CI평면을 제외하고는 통계적으로 유의한 차이를 보이지 않았으나, 사잇각은 FH평면이 가장 작게 나타났다. FH평면은 Po과 Or중 어느 3점을 선택하더라도, 통계적으로 유사한 재현도를 보였다. FH1과 FH2의 사잇각과 FH3과 FH4의 사잇각은 1° 이하의 적은 오차를 보이며, FH3과 FH4의 사잇각이 통계적으로 더 작은 차이를 보였다. 정중시상면의 재현도는 FMS-Nc, Na-Rh, Na-ANS, Rh-ANS, FR-PNS를 기준으로 설정한 경우를 제외하면, 0.61~1.93° 의 양호한 값을 보였다. 이상의 결과에 의하면 공간에서 정의되는 평면의 재현도는 평면을 정의하는 점 자체의 식별오차뿐 아니라, 각 점의 위치관게에도 영향을 받는 것을 알 수 있었다. 따라서, 안정적인 3차원 기준좌표계를 구성하려면 양측 Po과 편측 Or으로 구성되는 평면을 수평기준면으로, 수평면에 수직이고, Foramen Spinosum의 중점과 Nc를 포함하는 평면을 수직기준면으로, 수평면과 수직면에 수직이고, clinoidale나 sella, PNS를 지나는 평면을 전두면으로 설정하는 것이 바람직할 것으로 생각된다.

運動量(Momentum)이동이 경기기록에 끼치는 影響에 關한 硏究 : 垂直路를 中心으로

徐國雄 서울대학교 교양과정부 1974 論文集 Vol.6 No.-

The purpose of this study was to investigate the relationship between record of atheletics and transfor of momentum. The subjects (male 95 female 16) were tested transfor of momentum. The way of test as follows (1) Stand facing a wall with both arms stretched, overhead jump as high as possible and recorded the score. (2) Perform the same jump with the use of the arms starting at a position at the side of the body. Recorded that score. The results show that transfor of momentum effects seriously on the record of atheletics and especially the height is highest coefficient of corretation among physique. In order to develop the record of atheletics, we should try to investigate transofr momentum on all kinds of physical activities.

Pick-Up Base의 유연성이 시스템의 고유진동수에 미치는 영향

김국원 순천향대학교 부설 산업기술연구소 2004 순천향 산업기술연구소논문집 Vol.10 No.2

A Slim type disk drive used for a notebook computer has a rubber mount of high stiffness to cope with space restriction and internal pick-up base vibration. In this case, the flexibility of pick-up base may have an effect on the dynamic characteristics of an optical disk system. In this paper, a theoretical model considering the effects of flexibility of pick-up base on the natural frequency of optical disk system is proposed. In the model, the pick-up base is assumed to consist of two mass and one stiffness. The transmissibility experiments are performed, which confirms the usefulness of proposed model.

무인감시시스템 구현을 위한 이동체 인식 알고리즘에 관한 연구

장국렬,방만원,박진홍,박순영 木浦大學校 情報産業硏究所 1996 情報産業硏究誌 Vol.4 No.-

In this paper, an effective algorithm which can detect moving objects from the image sequences and classify an intruder from other moving objects is presented for an implementation of unmanned surveillance system. The proposed algorithm uses a stick figure model for features of the moving object since the stick figure model can be represent the characteristics of the moving objects. The stick figure model is extracted by applying the thining algorithm to the binary difference image between the reference and the image of a moving object. The computer simulation is carried out to analyze the performance of the proposed algorithm. The results show that the algorithm can discriminate a moving person and a moving animal with high degree of reliability.

고무재료의 경도와 변형률 에너지 함수에 관한 연구

김국원 순천향대학교 부설 산업기술연구소 2001 순천향 산업기술연구소논문집 Vol.7 No.1

Up to now, several mathematical theories based on strain energy functions have been developed for rubber materials. These theories, coupled with the finite element method, can be used very effectively by engineers to analyze and design rubber components. However, due to the complexities of the mathematical fomulations and the lack of general guidelines available for the analysis of rubber components, it is a formidable task for a engineer to use these rubber theories. In this paper, a simple method for predicting the strain energy function (Neo-Hookean model and Mooney-Rivlin model) without any experiment is discussed. This method is based on an empirical equation to estimate elastic modulus from hardness. Compared with uniaxial tension tests and Mooney-Rivlin model from the measured data, the usefulness of this method is confirmed.

드릴 공구의 응력 해석을 위한 유한요소법의 적용

김국원 순천향대학교 부설 산업기술연구소 2004 순천향 산업기술연구소논문집 Vol.10 No.2

Drilling process is one of the most common, yet complex operations among manufacturing processes. The performance of a drill is largely dependent upon drilling forces. Many researches focused on the effects of drill parameters on drilling forces. In this paper, the integration of CAD/CAE for the drill tool is performed. The stresses occurring in drilling process are analyzed by finite element method. The analytic drilling forces considering the drill parameters and drilling conditions are used. With ANSYS, geometric modeling and mesh generation of drill is performed automatically. From the study, the optimal drill tool design and the drilling condition determination may be achieved.

日東壯遊歌 硏究 : 作家를 中心으로

金國昭 명지어문학회 1976 明知語文學 Vol.8 No.-

n형 산화물반도체 가스센서의 전기저항 측정을 통한 표면흡착종의 전이특성의 평가

송국현,박재환,박순자 경북대학교 센서기술연구소 1994 센서技術學術大會論文集 Vol.5 No.1

A simple method for evaluation of transition property of surface adsorbates was presented, which is based on electrical resistance of a n-type oxide semiconductor gas sensor in air, CO or H_(2) gas flow. It was explained that temperature on the turning points in a resistance-temperature plot in air is of a function of activation energies on the transition processes of OH, O_(2)^(-), O^(-) and O_(2)^(-) adsorbates. Temperatures showing a maximum gas sensitivity was also assigned to be related to the activation energies. Based on the slope of a log(resistance) vs log(CO concentration) curve, it was described that reaction constants of the transition processes can be known. Absolute value of the slope was also ascribed to be a parameter for the gas sensitivity in a low-concentrated gas flow. It was also narrated that not only the transition properties but also role of OH^(-) or O_(2)^(-) adsorbate in the gas-sensing reaction can be determined from the recovery time characteristics.

장기간 고농도 수유후 발행한 고장성 탈수증 2례

김국환,안영준,양은석,박상기,박영봉,문경래 朝鮮大學校 附設 醫學硏究所 1997 The Medical Journal of Chosun University Vol.22 No.2

Hypernatremia(serum sodium>150meq/L) is caused by conditions that produce an excessive gain of sodium or result in an excessive loss of body fluid that is greater than the loss of sodium. The prognosis for hypernatremic dehydration is poorer than isotonic or hypotonic dehydration, because severe hyperosmolarity may result in cerebral damage( seizures, cerebral hemorrhages, thromboses, and subdural effusions). This cerebral injury may result in a permanent neurologic deficit. We experienced two cases of hypernatremic dehydration. Theses cases may have resulted from faulty preparation of infant formulas, as with the use of condensed milk powder. The first case experienced seizures during treatment, but survived, yet the second case died in spite of intensive care.

유한요소법을 이용한 DC 브러쉬 모터의 동특성 해석

김국원 순천향대학교 부설 산업기술연구소 2001 순천향 산업기술연구소논문집 Vol.7 No.2

In this paper, described is a research on the dynamic characteristics of DS brush motor finite element method. A impact test is performed to obtain the natual frequencies, which valuate the usefulness of the finite element analysis. From the study, It is thought that this finite element model can be applicable for designing a new motor with improvement in dynamic characteristics.