• 조명전기설비학회논문지
• /
• 제23권2호
• /
• pp.154-160
• /
• 2009

본 논문은 친환경 절연재료인 Dry-Air 중 에폭시 수지의 연면절연특성을 구명하여 Dry-Air를 절연매체로 사용한 각종 절연설계 시에 응용 가능한 기초자료를 제공하고자 한다. 사용한 전극은 침 대 평판, 구 대 평판, KS M3015 전극으로써, 동일한 조건 하에서 전극의 종류에 따른 연면 절연 파괴 전압, 연면 거리, 연면방전 전계강도를 비교하였다. 연면전계강도는 침 대 평판 전극 하에서 가장 높게 나타났다. 또한 에폭시 수지의 두께와 지름을 변화시켰을 때의 연면 절연 특성은 에폭시 수지의 두께가 두꺼울수록, 지름이 길수록 연면 절연 파괴 전압이 높게 나타남을 확인하였다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2005년도 춘계학술대회 논문집
• /
• pp.459-466
• /
• 2005

In this paper, we have systematically formulated the equations concerned to the in-plane and out-of-plane motions and deformations of a thick circular beam by using the kinetic and strain energies in order to analyse natural frequencies of a thick ring. The effects of variation of radius of curvature across the cross-section and also the effects of bending shear, extension and twist are considered. The equations of motion for natural vibration analysis of a ring are obtained utilizing the cyclic symmetry of vibration modes of the ring. The frequencies calculated using thick ring model and thin ring model are compared and discussed with the ones obtained from finite element analysis using the method of cyclic symmetry with 20-node hexahedral solid elements for rings with the different ratio of radial thickness to mean radius.

• 치과방사선
• /
• 제6권1호
• /
• pp.7-14
• /
• 1976

This study was done using the 45° oblique lateral old, 18 males and 27 females, with normal occlusion, premolars and molars on upper and lower jaws. Axial inclination to nasal floor, occlusal plane and inter-axial inclination were examined. In addition the position of each tooth was examined in height and depth in upper and lower jaws. The results were obtained as follows; 1. The inclination of long axis of upper 1st premolar was most nearly perpendicular, upper canine was tilted mesially, and 2nd premolar and molars were tilted distally. 2. The inclination of long axis of lowers molar were tilted mesially. 3. There were no severe variation on the inter-axial inclination of canine to mandibular plane, and 2nd molar.

• 한국농공학회지
• /
• 제37권2호
• /
• pp.64-72
• /
• 1995

A series of cubical triaxial tests with three independent principal stresses was per- formed on Baekma river sand( # 40~100). It was found that the major principal strain at failure remained approximately constant for b values larger than about 0.3 for both the drained and undrained condition, and thereafter increased as b value decreased. The test results showed that the direction of the strain increment at failure form acute angles with the failure surfaces for both the drained and undrained condition. The results were thus not in agreement with the normality condition from classic plasticity theory. Howev- er, it was found that the projections of the plastic strain increment vectors on the octahe- dral plane were perpendicular to the failure surface in that plane. Failure strength in terms of effective stress anlaysis was greatly influenced by the variation of intermediate principal stress and so was failure criterion. The effective stress failure surfaces for both the drained and undrained condition were estimated quite well by use of Lade's failure criterion.

• 치과방사선
• /
• 제2권1호
• /
• pp.47-51
• /
• 1972

The author measured the distance from mental foramen to the occusal plane and classified the positional frequency of mental foramen to the tooth site using topography. The results were obtained as follow; 1. Of 964 mental foramen taken, the common site was in 2nd premolar region showing 64.08 per cent in right and 57.17 per cent in left site. 2. The average distance from occlusal plane to the upper border of premolar region was 23.20㎜. and lower border was 25.07㎜. 3. The positional variation of mental foramen was 4.77 per cent were located above the apex of the nearest tooth, and 50.42 per cent were located at the apex of the nearest tooth and 44.81 per cent were located below the apex of the nearest tooth.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1995년도 하계학술대회 논문집 B
• /
• pp.989-991
• /
• 1995

In this paper, we present a new morphological texture spectrum approach to obtain a surface orientation using the variation of texture image caused by projective distortions. Under the assumption that the surface of texture image is smooth continuous, and specially plane or sphere, we apply the mathematical morphology and texture spectrum in order to compute the 3-D surface orientation. If the surface of texture image is plane, the surface orientation can be obtained through a simple procedure. If the surface of texture image is sphere, we find the centroids of texels, and may compute several major axes, their slopes, and vanishing points. Using the texture spectrum between the intersections of the vanishing points and the size of elements in each texels, we can find the surface orientation of texels on the sphere.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
• /
• pp.75-80
• /
• 2002

The mainly used technique to rectify satellite images with distortion is to develop a mathematical relationship between the pixel coordinates on the image and the corresponding points on the ground. By defining the relationship between two coordinate systems, a polynomial model is designed and various linear transformations are used. These GCP based geometric correction has performed overall plane to plane mapping. In the overall plane mapping, overall structure of a scene is considered, but local variation is discarded. The highly variant height of region is resampled with distortion in the rectified image. To solve this problem this paper proposed the TIN-based rectification on a satellite image. The TIN based rectification is good to correct local distortion, but insufficient to reflect overall structure of one scene. So, this paper shows the experimental result and the analysis of each rectification model. It also describes the relationship GCP distribution and rectification model. We can choose a geometric correction model as the structural characteristic of a satellite image and the acquired GCP distribution.

• 한국정보전자통신기술학회논문지
• /
• 제6권3호
• /
• pp.162-167
• /
• 2013

원형 구조를 갖는 평면 모노폴 UWB 안테나에서 접지면의 구조와 크기에 따른 입력 반사계수 특성의 변화를 연구하고, UWB 안테나가 장착되는 응용 기기에 따른 최적 접지면 구조와 크기를 제시하였다. 기준이 되는 원형 모노폴 안테나를 UWB 주파수 대역에서 동작하도록 반경 R 을 설계하였으며, 이 원형 모노폴을 수평면 접지 구조의 중심점에 올리고 시뮬레이션과 측정을 수행하여 양호한 결과를 얻었다. 연구 결과, 원형 모노폴의 반경이 작을 때 접지면의 적정 크기와 모노폴의 반경이 클 때 접지면의 최소 크기를 규정할 수 있었다.

• 한국전자파학회:학술대회논문집
• /
• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
• /
• pp.464-467
• /
• 2003

In this paper, to reduce the patch size of microstrip antenna, folded surface-type patch antenna is designed and fabricated. Size reduction could be achieved because of the downed resonant frequency by the extended current path passing along below the transformated patch surface. Comparison of the patch size at the 1.575 GHz between plane type(length 82 mm${\times}$width 90 mm) and "ㄷ"-shaped folded type is carried and comparision of frequency variation at the same patch size is carried. The result is like that the patch size was reduced than the plane type by 60 mm(73.17 %) at the same frequency. Therefore, it could be checked that "ㄷ"-shaped folded type antenna is advantageous than the plane type in size reduction.

• 제어로봇시스템학회논문지
• /
• 제4권1호
• /
• pp.45-55
• /
• 1998

In this paper, a robust path tracker and depth controller of Autonomous Underwater Vehicle based on sliding mode control is presented. We have also designed augmented equivalent control inputs by analyzing the sliding mode with the reaching mode. This can enhance the reaching rate, and improve chattering problems, that is, noise caused by the control plane actuator of the vehicle, which is one of the problems that occur when sliding mode control is used. Also to resolve the steady state error generated in the path tracker under current effect, a modified sliding plane is constructed. Also a redesigned sliding plane and control input using transformation matrix is proposed to do easy design of MIMO depth controller. For state variables that cannot be measured directly, reduced order sliding mode control is used to design an observer. The performance of designed path tracker and depth controller is investigated by computer simulation. The results show that the proposed control system has robust performance to parameter variation, modelling error and disturbance.