• Journal of the Korean Institute of Gas
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• v.12 no.2
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• pp.92-98
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• 2008

A combination of the instrumented indentation and 3D morphology measurement has been tried in order to perform a real-time property measurement of degraded materials in gas pipelines; three-dimensional indent morphologies were recorded using a reflective laser scanner after a series of insturmented indentations on three metallic specimens. Dimensions of the permanent deformation zone and contact boundary were analyzed from the cross-sectional profile over an remnant indent and used for estimating yield strength and hardness, respectively. Estimated yield strength was comparable with that from uniaxial tensile test and actual hardness implying material pile-up effects was lower than the calculated value from indentation curve by $20{\sim}30%$. It means that this 3D image analysis can explain the material pile-up effects on the contact properties. Additionally, a combined system of indentation and laser sensor was newly designed by modifying a shape of the indentation loading fixture.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.447-448
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• 2007

Product development is consisting by trend that accommodate almost function digital cam in camera phone that can speak of Mobile appliance, and competition about number of elemental area of image sensor is consisting for market prior occupation between these. Propose in this research and small size camera phone self-focusing adjustment actuator that do city manufacture is similar with general storehouse pickup actuator drive way, but selected in cylindrical to reduce space that lens holder occupies because there is restriction loading of lens and space enemy. Target number of research established that execute drive displacement more than $600{\mu}m$ in 2.75V that is house voltage that is used in Mobile device that is general. Also, described about maximum transfer displacement characteristic, displacement response characteristic, hysteresis, response characteristic, smallest transfer step characteristic, actuator's drive characteristic that is manufactured to examination item of maximum consumption electric power by special quality estimation system that apply laser displacement sensor that produce itself to evaluate city manufactured actuator's special quality.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.4
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• pp.151-158
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• 2005

An important component of a cooling tower is an axial fan, and there happens distortion in its shape which brings significant loss of efficiency. In this paper, a surface profile measuring system for large size axial fan of cooling towers is developed. A laser sensor is used as a measuring device and aluminum profiles and stepping motors are engaged into the system as frame structure and driving devices respectively. The measuring data are compared to the design data to compute the distortion of the axial fans. Two types of errors, axial and twist errors, are used to represent the precision of axial fan distortion. Genetic algorithm is used to solve the optimization problem during computing the precision. Results are displayed three dimensionally in a solid-modeler as well as 2-D drawings to help users find it with ease.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.1
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• pp.23-30
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• 2009

This paper addresses how to make a formation of multiple unmanned aerial vehicles (UAVs) using only the relative range information. Since the relative range can easily be measured by an on-board range sensor like the laser range finder, the proposed method does not require any expensive and heavy wireless communication system to share the navigation information of each vehicle. Based on the two-dimensional (2-D) nonlinear equations of motion, we propose a nonlinear formation controller using the typical input-output feedback linearization method. The performance of the proposed formation controller is verified by various numerical simulations.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.1
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• pp.35-39
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• 2003

The display technology on the retina is the key role in inspecting the condition of the patients. 2-dimensional retina image is widely used in the eye examination as of today. Recently, 3-dimensional retina image ones have been introduced to this area, but the quality of the image is not fully satisfied to the operator. For the purpose of developing 3-D retina imaging instrument, the optimization of a 3-D retina imaging system using Code-V tool was investigated in this thesis. He-Ne laser having the wavelength 632.8 nm was used to make a power source to detect the retina. Several lenses and mirrors installed on sledge which were developed to perform focus control on 3-D device were designed to make a beam focusing and direct line. Polygon scanner having 24 mirror facets and galvanometer making tilting movement were utilized to make a 2-D laser plane. Also, design of eye ball had been fulfilled to see the focus of the 2-D plane. Reflected ray from retina detected on the sensor array with the same path. All cognitive components were optimized for aberration correction in order to focus on retina. Results of optimization were compared to those of initial designed optics system. On the basis of above results, the result of third aberration has been corrected to stable values to the optical system. MTF evaluating the resolution of an image has been closely correlated to the diffraction limit and PSF indicating the strength distribution of an image has shown the SR value as 0.9998 having high performance. The possibility of new and powerful 3-D retina image instrument was verified by simulating each component of the instrument by Code-V.

• Journal of Sensor Science and Technology
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• v.11 no.6
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• pp.358-364
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• 2002

In this paper, we used U.V.(wavelength, 355nm) laser for adjusting Pt thin films temperature sensor to $100{\Omega}$ at $0^{\circ}C$. Internationally, A-class tolerance of temperature sensor is $0.06{\Omega}$ at $0^{\circ}C$. This is under value of $0.15^{\circ}C$, actually, so high-fine trimming technology is essential to this process. The width of trimmed lines was about $10{\mu}m$ and the best trimming of Pt thin films of $1{\sim}1.5{\mu}m$ was carried out with power : 35mW, rep. rate frequency : 200Hz and bite size : $1.5{\mu}m$. And using photolithography process, 96 resistors were fabricated in $2"{\times}2"$ substrate as the proportion of $79{\sim}90{\Omega}$ and $91{\sim}102{\Omega}$ is 42.7% and 57.3%, respectively. As result of trimming resistors to the target value of $109.73{\Omega}$ at $25^{\circ}C$, 82.3% of resistors had the tolerance within ${\pm}0.30{\Omega}$ and the others(17.7%) were within ${\pm}0.06{\Omega}$ of A-class tolerance.

• Korean Journal of Materials Research
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• v.8 no.3
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• pp.263-267
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• 1998

In this study, we have fabricated in-situ multilayer $YBa_2Cu_3O_{7-\delta}$/$SrTiO_{3}$/$YBa_2Cu_3O_{7-\delta}$ ramp edge type junctions by using a metal mask and pulsed laser deposition method and studied the junction properties. The junctions showed RSJ-like I-V characteristics. The normal state junction resistance R, of $18 \omega$ was nearly constant with temperature. The dc-SQUID sensors fabricated with the junctions show a sensitivity that transfer function dV/$d\Phi$)~$22\mu$V/$\Phi_{0}$, indicating that the in-situ ramp edge type junction is potentially useful for sensor application.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.4
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• pp.389-394
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• 2006

Inaccurate localization exposes a robot to many dangerous conditions. It could make a robot be moved to wrong direction or damaged by collision with surrounding obstacles. There are numerous approaches to self-localization, and there are different modalities as well (vision, laser range finders, ultrasonic sonars). Since sensor information is generally uncertain and contains noise, there are many researches to reduce the noise. But, the correctness is limited because most researches are based on statistical approach. The goal of our research is to measure more exact robot location by matching between built VRML 3D model and real vision image. To determine the position of mobile robot, landmark-localization technique has been applied. Landmarks are any detectable structure in the physical environment. Some use vertical lines, others use specially designed markers, In this paper, specially designed markers are used as landmarks. Given known focal length and a single image of three landmarks it is possible to compute the angular separation between the lines of sight of the landmarks. The image-processing and neural network pattern matching techniques are employed to recognize landmarks placed in a robot working environment. After self-localization, the 2D scene of the vision is overlaid with the VRML scene.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.318-320
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• 2006

Inaccurate localization exposes a robot to many dangerous conditions. It could make a robot be moved to wrong direction or damaged by collision with surrounding obstacles. There are numerous approaches to self-localization, and there are different modalities as well (vision, laser range finders, ultrasonic sonars). Since sensor information is generally uncertain and contains noise, there are many researches to reduce the noise. But, the correctness is limited because most researches are based on statistical approach. The goal of our research is to measure more exact robot location by matching between built VRML 3D model and real vision image. To determine the position of mobile robot, landmark-localitzation technique has been applied. Landmarks are any detectable structure in the physical environment. Some use vertical lines, others use specially designed markers, In this paper, specially designed markers are used as landmarks. Given known focal length and a single image of three landmarks it is possible to compute the angular separation between the lines of sight of the landmarks. The image-processing and neural network pattern matching techniques are employed to recognize landmarks placed in a robot working environment. After self-localization, the 2D scene of the vision is overlaid with the VRML scene.

• Journal of Korea Water Resources Association
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• v.55 no.11
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• pp.931-939
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• 2022

In Korea, about two-thirds of the precipitation is concentrated in the summer season, so the problem of turbidity in the summer flood season varies from year to year. Concentrated rainfall due to abnormal rainfall and extreme weather is on the rise. The inflow of turbidity caused a sudden increase in turbidity in the water, causing a problem of turbidity in the dam reservoir. In particular, in Korea, where rivers and dam reservoirs are used for most of the annual average water consumption, if turbidity problems are prolonged, social and environmental problems such as agriculture, industry, and aquatic ecosystems in downstream areas will occur. In order to cope with such turbidity prediction, research on turbidity modeling is being actively conducted. Flow rate, water temperature, and SS data are required to model turbid water. To this end, the national measurement network measures turbidity by measuring SS in rivers and dam reservoirs, but there is a limitation in that the data resolution is low due to insufficient facilities. However, there is an unmeasured period depending on each dam and weather conditions. As a sensor for measuring turbidity, there are Optical Backscatter Sensor (OBS) and YSI, and a sensor for measuring SS uses equipment such as Laser In-Situ Scattering and Transmissometry (LISST). However, in the case of such a high-tech sensor, there is a limit due to the stability of the equipment. Therefore, there is an unmeasured period through analysis based on the acquired flow rate, water temperature, SS, and turbidity data, so it is necessary to develop a relational expression to calculate the SS used for the input data. In this study, the AEM3D model used in the Water Resources Corporation SURIAN system was used to improve the accuracy of prediction of turbidity through the turbidity-SS relationship developed based on the measurement data near the dam outlet.