• Journal of Mechanical Science and Technology
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• 제19권10호
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• pp.1891-1901
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• 2005

Recently the authors tried to find damage position only using measured frequency response functions. According to their work, it seems that the algorithm is very practical since it needs only measured frequency responses while other methods require exact analytic model. But when applying the method to a real structure, it requires lots of experiment. The authors, in this time, propose a method to reduce its experimental load by detecting damage within a substructure. This method searches damages not within an entire structure but within substructures. In addition, damage severity was treated in this paper since it is worthy to know damage severity. Optimization technique is used to estimate damage level using measured responses and damage model. Two test examples, a plate and a jointed structure, are chosen to verify the suggesting method.

• 소성∙가공
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• 제19권5호
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• pp.320-324
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• 2010

Multi-Layer Ceramic Circuit(MLCC) in the face of thousands of fine pitch multi hole is processed. However, the fine pitch multi hole has a size of only a few micrometers. Therefore, in order to curtail the measurement time and reduce error, the image processing measurement method is required. So, we proposed an image processing measurement algorithm which is required to accurately measure the fine pitch multi hole. The proposed algorithm gets image of the fine pitch multi hole, extracts object from the image by morphological process, and extracts the parameters of its position and feature by edge detecting process. In addition, we have used the sub-pixel algorithm to improve accuracy. As a result, the proposed algorithm shows 97% test-retest measurement reliability within 2 ${\mu}m$. We found that the algorithm was wellsuited for measuring the fine pitch multi hole.

• 한국통신학회논문지
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• 제24권7A호
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• pp.1022-1027
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• 1999

본 논문은 CDMA 단말기의 위치추정방법으로 기지국 순방향 Pilot신호의 단말기 도착시간의 차(TDOA)를 이용하는 기법을 제안한다. 단말기 Searcher는 기지국의 Pilot신호를 획득하여 TDOA를 측정한다. 이를 위하여 Searcher의 Processing 이득은 매우 중요하다. 이득은 신호의 동기누적구간에 비례함을 이론적으로 유도하고 분석하였으며 이를 증거함으로서 미약한 Pilot신호의 획득과 안정적인 TDOA값의 측정이 가능함을 Field 시험하였다. 또한, 신호의 세기는 전송거리에 따라 지수적으로 감쇄한다. 그러므로, Searcher 이득의 향상은 기지국에서 멀리 떨어진 곳에서도 Pilot신호의 획득을 가능하게 한다. 셀 내 신호세기에 대하여 가능한 위치추정영역의 변화를 컴퓨터로 모의실험 하였다. Shadow 영향을 무시하고도 90%이상의 영역을 포함하기 위하여 -35dB이하의 신호검출이 필요함을 제시하였다. 따라서, 미약한 Pilot신호 획득을 통한 위치추정영역의 확장과 안정적인 TDOA값의 측정을 위하여 Searcher 동기누적구간의 최대화가 요구된다.

• 전기학회논문지
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• 제56권1호
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• pp.117-122
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• 2007

LB method is one of the most interesting technique to arrange certain molecular groups at precise position relative to others. Also, the LB deposition technique can fabricate extremely thin organic films with a high degree of control over their thickness and molecular architecture. In this way, new thin film materials can be built up at the molecular level, and the relationship between these artificial structures and the properties of materials can be explored. In this paper, evaluation of physical properties was made for dielectric relaxation phenomena by the detection of the surface pressures and displacements current on the monolayer films of phospolipid monomolecular DLPC. Lipid thin films were manufacture by detecting deposition for the accumulation and the current was measured after the electric bias was applied across the manufactured MIM device. It is found that the phospolipid monolayer of dielectric relaxation takes a little time and depend on the molecular area. When electric bias is applied across the manufactured MIM device by the deposition condition of phospolipid mono-layer, it wasn't breakdown when the higher electric field to impress by increase of deposition layers.

• Structural Engineering and Mechanics
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• 제28권5호
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• pp.525-548
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• 2008

This article deals the theory for solving an inverse problem of plate structures using the frequency-domain information instead of classical time-domain delays or free vibration eigenmodes or eigenvalues. A reduced set of output parameters characterizing the defect is used as a regularization technique to drastically overcome noise problems that appear in imaging techniques. A deconvolution scheme from an undamaged specimen overrides uncertainties about the input signal and other coherent noises. This approach provides the advantage that it is not necessary to visually identify the portion of the signal that contains the information about the defect. The theoretical model for Quantitative nondestructive evaluation, the relationship between the real and ideal models, the finite element method (FEM) for the forward problem, and inverse procedure for detecting the defects are developed. The theoretical formulation is experimentally verified using dynamic responses of a steel plate under impact loading at several points. The signal synthesized by FEM, the residual, and its components are analyzed for different choices of time window. The noise effects are taken into account in the inversion strategy by designing a filter for the cost functional to be minimized. The technique is focused toward a exible and rapid inspection of large areas, by recovering the position of the defect by means of a single accelerometer, overriding experimental calibration, and using a reduced number of impact events.

• 한국위성정보통신학회논문지
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• 제8권2호
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• pp.12-16
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• 2013

본 논문에서는 스마트폰을 이용한 모바일 소프트웨어 응용 기술 개발에 관한 연구를 수행하였다. 우선, 스마트폰에 장착된 LED 플래쉬 백라이트를 이용하여 스마트폰의 통신과는 별도로 부가적인 위치 데이터를 전송할 수 있는 기법을 제시하였고, 이와 더불어 스마트폰 사용자의 위치와 연계되는 가시광 기반 빔포밍 통신을 위한 원격제어 기능을 수행하는 스마트폰 리모콘 앱(어플리케이션)을 개발하였다. 스마트폰의 LED 플래쉬 백라이트를 이용한 데이터 전송기법은 송신기로서 기존의 스마트폰의 플래쉬 백라이트를 기반으로 OOK 데이터 전송방식을 적용하였으며 수신부는 포토다이오드 기반의 검출기를 적용하였다. 또한 리모콘 앱의 경우에는 WiFi와 연동하여 언제 어디서나 IP기반으로 스마트폰 사용자의 위치에 부합되는 가시광 빔포밍 통신을 위한 원격 제어 기능으로 구현하였다. 본 논문에서 제안한 스마트폰과 모바일 소프트웨어 기반의 응용기술은 유비쿼터스 위치인식 응용사례로서 널리 활용될 수 있을 것으로 기대된다.

• Journal of Animal Science and Technology
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• 제63권6호
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• pp.1453-1463
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• 2021

Feeding is the most important behavior that represents the health and welfare of weanling pigs. The early detection of feed refusal is crucial for the control of disease in the initial stages and the detection of empty feeders for adding feed in a timely manner. This paper proposes a real-time technique for the detection and recognition of small pigs using a deep-leaning-based method. The proposed model focuses on detecting pigs on a feeder in a feeding position. Conventional methods detect pigs and then classify them into different behavior gestures. In contrast, in the proposed method, these two tasks are combined into a single process to detect only feeding behavior to increase the speed of detection. Considering the significant differences between pig behaviors at different sizes, adaptive adjustments are introduced into a you-only-look-once (YOLO) model, including an angle optimization strategy between the head and body for detecting a head in a feeder. According to experimental results, this method can detect the feeding behavior of pigs and screen non-feeding positions with 95.66%, 94.22%, and 96.56% average precision (AP) at an intersection over union (IoU) threshold of 0.5 for YOLOv3, YOLOv4, and an additional layer and with the proposed activation function, respectively. Drinking behavior was detected with 86.86%, 89.16%, and 86.41% AP at a 0.5 IoU threshold for YOLOv3, YOLOv4, and the proposed activation function, respectively. In terms of detection and classification, the results of our study demonstrate that the proposed method yields higher precision and recall compared to conventional methods.

• 한국멀티미디어학회논문지
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• 제18권6호
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• pp.701-709
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• 2015

Image stitching method is a technique for obtaining an high-resolution image by combining two or more images. In X-ray image for clinical diagnosis, the size of the imaging region taken by one shot is limited due to the field-of-view of the equipment. Therefore, in order to obtain a high-resolution image including large regions such as a whole body, the synthesis of multiple X-ray images is required. In this paper, we propose a rapid stitching method of digital X-ray images using template-based registration. The proposed algorithm use principal component analysis(PCA) and k-nearest neighborhood(k-NN) to determine the location of input images before performing a template-based matching. After detecting the overlapping position using template-based matching, we synthesize input images by alpha blending. To improve the computational efficiency, reduced images are used for PCA and k-NN analysis. Experimental results showed that our method was more accurate comparing with the previous method with the improvement of the registration speed. Our stitching method could be usefully applied into the stitching of 2D or 3D multiple images.

• IEIE Transactions on Smart Processing and Computing
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• 제2권1호
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• pp.27-35
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• 2013

This paper proposes a face tracking algorithm for a viewpoint adaptive multi-view synthesis system. The original scene captured by a depth camera contains a texture image and 8 bit gray-scale depth map. From this original image, multi-view images that correspond to the viewer's position can be synthesized using geometrical transformations, such as rotation and translation. The proposed face tracking technique gives a motion parallax cue by different viewpoints and view angles. In the proposed algorithm, the viewer's dominant face, which is established initially from a camera, can be tracked using the statistical characteristics of face colors and deformable templates. As a result, a motion parallax cue can be provided by detecting the viewer's dominant face area and tracking it, even under a heterogeneous background, and synthesized sequences can be displayed successfully.

• 전자공학회논문지A
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• 제31A권5호
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• pp.113-120
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• 1994

Silicon flow sensor that can detect the velocity and direction of air flow was designed and fabricated by integrated circuit process and bulk micromachining technique. The flow sensor consists of three-layered dielectric diaphragm, a heater at the center of the diaphragm, and four thermopiles surrounding the heater at each side of diaphragm as sensing elements. This diaphragm structure contributes to improve the sensitivity of the sensor due to excellent thermal isolation property of dielectric materials and their tiny thickness. The flow sensor has good axial symmetry to sense 2-D air flow with the optimized sensing position in the proposed structure. The sensor is fabricated using CMOS compatible process followed by the anisotropic etching of silicon in KOH and EDP solutions to form I$\mu$ m thick dielectric diaphragm as the last step. TCR(Temperature Coefficient of Resistance) of the heater of the fabricated sensors was measured to calculate the operating temperature of the heater and the output voltage of the sensor with respect to flow velocity was also measured. The TCR of the polysilicon heater resistor is 697ppm/K, and the operating temperature of the heater is 331$^{\circ}C$ when the applied voltage is 5V. Measured sensitivity of the sensor is 18.7mV/(m/s)$^{1/2}$ for the flow velocity of smaller than 10m/s.