• 지질공학
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• 제5권2호
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• pp.233-235
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• 1995

단순히 일축성으로만 보이는 선현 구조의 정향은 다른 조직 요소와 결합되어 있을 경우 입체적으로 이해되어야 한다. 그것은 측정과 보정 뿐만 아니라 분석 과정에도 필요하다.

• 열처리공학회지
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• 제31권5호
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• pp.237-243
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• 2018

In-rich InGaN epilayers were grown on (0001) sapphire substrates by radio-frequency plasma-assisted molecular beam epitaxy (RF-MBE). InGaN epilayers grown at various growth condition were observed by SEM, XRD, and RHEED. When plasma power of nitrogen increased from 290 to 350 W, surface morphology and crystal quality became worse according to more active nitrogen on the surface of InGaN at N-rich growth condition. As In composition was reduced from 89 to 71% by changing the incoming flux of In and Ga, surface morphology and crystal quality became worse. In addition, weak peaks of cubic InGaN phase was observed from InGaN layer with 71% In composition by XRD ${\Phi}$ scan measurement. When growth temperature decreased from 500 to $400^{\circ}C$, RHEED diffraction pattern was changed to be from streaky to spotty which means atomically rough surface, and spotty pattern showed cubic symmetry of InGaN clearly. XRD ${\Phi}$ scan measurement gave clear evidence that more cubic InGaN phase was formed at low growth temperature. All these results indicates that extremely low surface mobility of Ga adatom caused inferior crystal quality and cubic InGaN phase.

• 한국정밀공학회지
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• 제20권2호
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• pp.184-191
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• 2003

A parallel manipulator has high stiffness and all the joint errors on the device are not accumulated at the end -effector unlike a serial manipulator. These are the reasons why the parallel manipulator has been widely used in many fields of industry. In the parallel manipulator, it is very important to predict the exact pose of the end-effector when we want to control the end-effector motion. Installation errors have to be determined in order to predict and control the actual position and pose of the end-effector. This paper presents an algorithm to find the whole 36 joint error components with joint clearance errors and measurement errors considered, when a link length measurement sensor is used and data more than 36 times are acquired for 36 different configurations. A simulation test using this algorithm is performed with a Matlab program which uses the Levenberg-Marquardt method that is known to be efficient for non-linear optimization.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2007년도 추계종합학술대회
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• pp.285-288
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• 2007

3차원 초음파 센싱에 의해 획득한 데이터로부터 물체의 부피를 자동으로 측정하고 분류적재 관리하는 임베디드시스템을 프로세서 기반으로 구현한다. 부피측정은 3개의 초음파 센서에서 획득한 데이터에서 높이와 폭은 물체가 컨베이어를 통과할 때 3 값을 기준 값과 비교하여 측정하고 길이는 물체가 처음 감지된 시점부터 범위를 벗어날 때까지의 시간을 물체의 이동속도에 대입하여 측정한다. 또한 센서의 온도 변화에 속도가 변하기 때문에 환경에 따라 보정하고 물체가 정방향이 아닐 경우 센싱값을 평균하여 오차를 줄인다. 실험은 직육면체를 기준하였으며 포장된 물류를 크기별로 분류하고 창고 및 이동체에 적재 할 경우 실용적으로 활용가능성을 높인다.

• 센서학회지
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• 제18권6호
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• pp.441-448
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• 2009

Magnesia partially stabilized zirconia(Mg-PSZ) solid electrolytes for an improvement of thermal shock resistance, which is suitable for the measurement of oxygen activity in a molten steel, were prepared by post-thermal aging treatment. The steelmaking oxygen sensor elements were formed by an injection molding method, sintered at $1650^{\circ}C$, and then thermal aged ranged from 1250 to $1400^{\circ}C$. Sintered density and porosity were decreased as increasing the magnesia content in a zirconia-magnesia solid solution. Fractions of cubic phase to the synthesized Mg-PSZ solid electrolytes were ranged from 13.13 to 79.54.% after post-thermal aging treatment. Very dense microstructure without voids in the grains was obtained by the post-thermal aging process. Fine tetragonal phase crystallites precipitated on the cubic surface during post-thermal aging up to $1300^{\circ}C$ improve a thermal shock resistance and reappearance of electro motive force(EMF) curve.

• Journal of the Optical Society of Korea
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• 제17권5호
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• pp.399-404
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• 2013

This article proposes a digital image correlation (DIC) strain measurement method based on a finite element (FE) algorithm. A two-step digital image correlation is presented. In the first step, the gradient-based subpixels technique is used to search the displacements of a region of interest of the specimen, and then the strain fields are obtained by utilizing the finite element method in the second step. Both simulation and experiment processing, including tensile strain deformation, show that the proposed method can achieve nearly the same accuracy as the cubic spline interpolation method in most cases and higher accuracy in some cases, such as the simulations of uniaxial tension with and without noise. The results show that it also has a good noise-robustness. Finally, this method is used in the uniaxial tensile testing for Dahurian Larch wood specimens with or without a hole, and the obtained strain values are close to the results which were obtained from the strain gauge and the cubic spline interpolation method.

• 대한가정학회지
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• 제20권3호
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• pp.9-18
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• 1982

In this study, we attempted to make an original pattern of clothing for an abnormal type of figure, especially for the type of kyphosis. We measured the curvature of the spine of a woman with kyphosis with a Martin measuring instrument and a silhouetter in the following ways. First, we counted the rate of shrinkage of the standard lines drawn on the surface of the body according as the body moved. Secondly, placing the front and back darts, the front and back shoulder darts and the side darts according to“Munhwa”pattern, we made cubic cuttings of four moving postures as well as the standing one. Thirdly, we superposed the developed patterns of the standing and the moving postures, measuring the position change and the amount of the chaange of the darts, and compared them. The results are as follows: 1) In the developed pattern of a cubic cutting of the basic pattern and the standing posture, the neckhole became larger than that of the basic pattern, and the waist line was lowered than that of the basic pattern because the center back line was shortened due to the curved backbone. 2) As for the change of the standard line according to the movement, we found that the waist line, the center front line, the center back line, the bust width line, the upper back width line and the back width line became longer. Special consideration must be given to the function of the clothing for an abnormal type of figure. 3) The difference of the measurements between the cubic cutting and the body measurement regardless of the body movement is due to a gap by an acute angle at the jutted place between the developed pattern and the body surface. We found that the body measurement of the upper back width line, the back width line and the bust line became larger. Consequently, in making an original clothing pattern, it is desirable that we must not place the front and the back waist darts at the jutted place on the back from the functional and the aesthetic viewpoint of clothing. It is also desirable that we must widen the neckhole because the shoulder angle is close to a straight line due to a jut of the upper back width line.

• Nuclear Engineering and Technology
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• 제42권1호
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• pp.9-16
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• 2010

Experimental examinations for evaluating fracutres were conducted by using transparent replicas of a single fracture in order to obtain the fracture data to contribute to the methodlogy on how to improve the definitaion of representative parameter values used for a parallel plate fracture model. Quantitative aperture distribution and quantitative tracer concentration data at each point in time were obtained by measuring the attenuation of transmitted light through the fracture in high spatial resolution. the representative aperture values evaluated from the multiple different measurement methods, such as arithmetic mean of aperture distribution measured by the optical method, transport aperture evaluated from the tracer test, and average aperture evaluated from the fracture void volume measurement converged to a unique value that indicates the accuracy of this experimental study. The aperture data was employed for verifying the numerical simulation under the assuption of Local Cubic Law and showed that the calculated flow rate through the fracture is 10%-100% larger than hydraulic test results. The quantitative tracer concentration data is also very valuable for validating existing numerical code for advection dispersion transport in-plane heterogeneous fractures.

• Korean Chemical Engineering Research
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• 제43권5호
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• pp.637-640
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• 2005

극성과 비극성의 물질인 methyl tert-butyl ether(MTBE)와 2,2,4-trimethylpentane 혼합물과 methyl ethyl ketone(MEK)와 2,2,4-trimethylpentane 2성분의 액체혼합물 그리고 극성의 물질인 MTBE과 MEK 2성분 액체혼합물의 밀도를 densitometer를 사용하여 278.15 K, 288.15 K, 298.15 K에서 각각 측정하였다. 측정한 밀도로부터 얻은 2성분계 과잉몰부피의 측정값과 Huron-Vidal의 혼합법칙을 사용한 Peng-Robinson-Stryjek-Vera(PRSV)의 3차 상태방정식으로부터 계산한 계산값이 잘 일치하였으며 극성물질을 포함한 혼합물의 몰부피 계산에 3차의 PRSV 상태방정식이 이용될 수 있음을 확인하였다.

• 한국시뮬레이션학회논문지
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• 제17권3호
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• pp.19-26
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• 2008

본 논문에서는 중기 국채(Treasure Note; T-Note)의 실제 자료를 이용하여 채권 가격에 대한 이자율을 예측하는 동적인 예측 알고리즘을 제안하고 있다. 제안한 알고리즘은 이자율 기간 구조를 근본으로 하고 있으며 표준 위너 과정(standard Wiener process)과 같은 다양한 금융 모형의 대안으로 활용 가능하다. 본 논문에서는 실제 자료의 누적 분포 함수(Cumulative Distribution Function; CDF)를 이용하여 이자율을 측정하였으며 CDF는 수치적 방법인 보간법 중에 자주 활용되는 내츄럴 큐빅 스플라인(natural cubic spline; NCS)방법을 통하여 얻었다. 위에서 얻은 CDF를 통하여 난수 생성기법(random number generation scheme; RNGS)을 이용하여 채권의 가격를 계산하였다. 컴퓨터 시뮬레이션을 통해 얻은 실험결과로부터 제안된 예측 알고리즘에서 엄밀도(precision)의 낮은 값을 얻음으로써 채권의 가치가 더욱 예리하고 정확하게 평가되었음을 확인할 수 있었으며, 이는 매우 근거 있는 예측이라 할 수 있다.