• 대한기계학회논문집B
• /
• 제30권3호
• /
• pp.270-277
• /
• 2006

Inverse radiation problems were solved for estimating boundary temperature distribution in a way of function estimation approach in an axisymmetric absorbing, emitting and scattering medium, given the measured radiative data. In order to reduce the computational time fur the calculation of sensitivity matrix, automatic differentiation and Broyden combined method were adopted, and their computational precision and efficiency were compared with the result obtained by finite difference approximation.. In inverse analysis, the effects of the precision of sensitivity matrix, the number of measurement points and measurement error on the estimation accuracy had been inspected using quasi-Newton method as an inverse method. Inverse solutions were validated with the result acquired by additional inverse methods of conjugate-gradient method or Levenberg-Marquardt method.

• 오토저널
• /
• 제9권5호
• /
• pp.6-18
• /
• 1987

Owing to remarkable development in automotive industry, vehicle performance comes close to perfection and guarantee of stability is getting emphasized in accordance with high speed trend in vehicle. In recent years, the utilization of automatic test method for research and development of automotive brake system is being propelled actively, which pursue whole automatic control from simple measurement to data acquisition. The main subject of this paper is to make a brief explanation on Micro computer controlled Automatic Test Method for Automotive Brake System which makes it possible to test with high accuracy and speed.

• 대한원격탐사학회지
• /
• 제24권4호
• /
• pp.341-349
• /
• 2008

본 논문은 위성영상을 이용한 변화정보를 취득하는데 있어 중요한 과정인 임계값 결정에 관한 새로운 기법을 제안하고 있다. 화소간 유사도 측정을 통해 도출된 결과 값을 일정 간격으로 누적 계산하고, 급격하게 변하는 지점을 임계값으로 결정하였다. 의사영상을 통해 기대최대화 기법, 교점방법과 성능을 비교하였으며, 두 시기의 ALI 영상과 Hyperion 영상에 실제 적용하여 변화탐지 결과를 확인하였다. 제안된 기법은 기존의 기법과 비슷한 수준의 변화탐지 결과 정확도를 확보할 수 있었으며, 기대최대화 기법에 비해 간단하게 적용할 수 있고, 교점방법과 달리 최빈 값을 둘 이상 가지는 히스토그램에도 적용할 수 있는 장점이 있어 향후 변화유무 정보 취득에 효과적으로 사용할 수 있을 것으로 기대한다.

• 대한통합의학회지
• /
• 제5권1호
• /
• pp.75-83
• /
• 2017

Purpose : The parameters used in architectural analysis are muscle thickness, fascicle length, pennation angle, etc. Pennation angle is an important muscle characteristic that plays a significant role in determining a fascicle's force contribution to movement. Ultrasonography has been widely used to obtain the image for measurement of a pennation angle since it is non-invasive and real-time. However, manual assessment in ultrasonographic images is time-consuming and subjective, making it difficult for using in muscle function analysis. Thus, in this study, I proposed an automatic method to extract the pennation angle from the ultrasonographic images of gastrocnemius muscle. Method : The ultrasonographic image obtained from 10 healthy participants's gastrocnemius muscle using for developed automatic measuring program. Automatic measuring program algorithm consists with preprocessing, line detection, line classification, and angle calculation. The resulting image was then used to detect the fascicles and aponeuroses for calculating the pennation angle with the consideration of their distribution in ultrasonographic image. Result : The proposed automatic measurement program showed the stable repeatability of pennation angle calculation. Conclusion : This study demonstrated that the proposed method was able to automatically measure the pennation angle of gastrocnemius, which made it possible to easily and reliably investigate pennation angle more.

• 제어로봇시스템학회논문지
• /
• 제9권3호
• /
• pp.227-235
• /
• 2003

We propose an algorithm for the automatic measurement of concentricity and roundness using image processing technique. The proposed measuring method consists of the preprocessing process and the measuring process. In the measuring process, two types of concentricity measurement algorithm and one type of roundness measurement algorithm are proposed. We could measure the concentricity and roundness using input image from CCD camera, without using special measurement equipment. From the experimental results, we could find that the required measurement accuracy specification is sufficiently satisfied using our proposed method.

• KIEE International Transaction on Systems and Control
• /
• 제2D권2호
• /
• pp.97-107
• /
• 2002

In this paper, we propose the concept of orthonormalized compressed measurement for the stability analysis of discrete linear time-varying Kalman filters. Unlike previous studies that deal with the homogeneous portion of Kalman filters, the proposed Lyapunov method directly deals with the stochastically-driven system. The orthonorrmalized compressed measurement provides information on the a priori state estimate of the Kalman filter at the k-th step that is propagated from the a posteriori state estimate at the previous block of time. Since the complex multiple-step propagations of a candidate Lyapunov function with process and measurement noises can be simplified to a one-step Lyapunov propagation by the orthonormalized compressed measurement, a stochastic radius of attraction can be derived that would be impractically difficult to obtain by the conventional multiple-step Lyapunov method.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제15권2호
• /
• pp.184-193
• /
• 2015

This paper proposes a cost-efficient and automatic method for large data acquisition from a test chip without expensive equipment to characterize random process variation in an integrated circuit. Our method requires only a test chip, a personal computer, a cheap digital-to-analog converter, a controller and multimeters, and thus large volume measurement can be performed on an office desk at low cost. To demonstrate the proposed method, we designed a test chip with a current model logic driver and an array of 128 current mirrors that mimic the random process variation of the driver's tail current mirror. Using our method, we characterized the random process variation of the driver's voltage due to the random process variation on the driver's tail current mirror from large volume measurement data. The statistical characteristics of the driver's output voltage calculated from the measured data are compared with Monte Carlo simulation. The difference between the measured and the simulated averages and standard deviations are less than 20% showing that we can easily characterize the random process variation at low cost by using our cost-efficient automatic large data acquisition method.

• ETRI Journal
• /
• 제39권1호
• /
• pp.76-86
• /
• 2017

In this study, we propose an automatic contrast enhancement method based on transfer function modification (TFM) by histogram equalization. Previous histogram-based global contrast enhancement techniques employ histogram modification, whereas we propose a direct TFM technique that considers the mean brightness of an image during contrast enhancement. The mean point shifting method using a transfer function is proposed to preserve the mean brightness of an image. In addition, the linearization of transfer function technique, which has a histogram flattening effect, is designed to reduce visual artifacts. An attenuation factor is automatically determined using the maximum value of the probability density function in an image to control its rate of contrast. A new quantitative measurement method called sparsity of a histogram is proposed to obtain a better objective comparison relative to previous global contrast enhancement methods. According to our experimental results, we demonstrated the performance of our proposed method based on generalized measures and the newly proposed measurement.

• 산업경영시스템학회지
• /
• 제41권4호
• /
• pp.248-255
• /
• 2018

Ensuring the quality of molds is one of the major issues in mass production. In general, securing the quality of the molds is achieved by repeating grinding and die spotting after machining the molds based on engineer's decision. However, this heuristic method is affected by the engineer's skill and working environment. Therefore, a lot of time and resources are needed in order to ensure quality. In this study, ensuring the quality of molds using grinding map which is generated using automatic measurement is proposed. An automatic measuring system based on CMM (Coordinate Measuring Machine) is developed for measuring the molds. This system generates the measurement path automatically using the 3D CAD model of products. CAD (ComputerAided-Design), CAM (Computer-Aided-Manufacturing), and CAQ (Computer-Aided-Quality) technology is integrated using DMIS (Dimensional Measuring Interface Standard) format in the automatic measuring system. After measuring the molds, a grinding map is generated using the gap between the CAD model and measured values of mold. The grinding map displays the machining tendency and the required amount of grinding with values on a 3D map. Therefore, the quality of molds can be ensured with exactness and quickness based on the grinding map. This study shows that integrating the planning, measuring, and analyzing based on computer technology can solve the problem of quality assurance of mold using the proposed method, therefore the productivity can be increased.

• 반도체디스플레이기술학회지
• /
• 제14권1호
• /
• pp.7-11
• /
• 2015

In this paper, an automatic focusing method has been proposed for speedy and reliable measurement and inspection in industry. It is very difficult to determine focusing step size and moving direction in one camera autofocusing. The proposed method can improve speed and accuracy of focusing by using the optical axis interval of two cameras, which is automatically set up as focusing step size. Also, it can determine moving direction from focus value comparisons of two cameras, and then solve ambiguity of one camera focusing. Its performance is verified by experiments. It is expected that it can apply to optical system for measurement and inspection in industry fields.