• Journal of the Microelectronics and Packaging Society
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• v.24 no.1
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• pp.57-65
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• 2017

The electronic components in mobile device are composed of electronic chips and various other materials. These components become extremely thin and the constituent materials have different coefficient of thermal expansion, so that considerable warpages occurs easily due to temperature change or external load. Shadow $moir{\acute{e}}$ is non-contact, whole field technique for measuring out-of-plane displacement, but the measurement sensitivity is not less than $50{\mu}m/fringe$, which is not suitable for measuring the warpage of the electronic components. In this paper, we implemented a measurement method with enhanced sensitivity of $25{\mu}m/fringe$ by investigating and optimizing various experimental conditions of the shadow $moir{\acute{e}}$. In addition, four $moir{\acute{e}}$ fringe patterns recorded by the phase shift are processes to obtain a $moir{\acute{e}}$ fringe patterns with a sensitivity four times higher. The measurement technique is applied to small electronic components of a smart phone for measuring warpage with a high sensitivity of $5{\mu}m/fringe$ at room temperature and at the temperature of $100^{\circ}C$.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1344-1368
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• 2007

The Advanced countries including Japan, USA and European countries are adopting automatic system(e.g., auto-measurement using CCD camera) for measuring pantograph sliding plate and wheel abrasion to minimize manpower for E.M.U(Electric Multiple Unit) inspection and maintenance as part of management rationalization of railroad Corporation since late 1980's. In Korea, as part of scheme of business rationalization, automatic system for measuring pantograph sliding plate and wheel abrasion started to draw industry attention since late 1990s, and the system started to be installed in newly built depots of Korea Railroad Corporation since 2002. This study hopefully provides the base for realizing business rationalization and applying the advanced technology developed by Korea, the country of powerful IT basis, to overseas railroad organizations by examining automatic system for measuring pantograph sliding plate abrasion using existing CCD cameras produced domestically and in foreign countries to study cases(organizations in Korea) for improvement of measurement, management and inspection of pantograph sliding plate abrasion using CCD cameras with new cutting-edge technology; and by applying the study result to railroad organizations in metropolitan areas in Korea.

• The Journal of the Convergence on Culture Technology
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• v.5 no.3
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• pp.263-269
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• 2019

In this study, the characteristics and operation of a multi-purpose loader equipped with various sensors such as a sensor capable of measuring the boom length, an angle sensor capable of measuring the tilt of the left and right sides of the boom and the loader, and a load cell capable of measuring the weight during lifting We have implemented a system that displays related data values. The configuration of the system reads the values from the sensors, sends them to the vehicle controller, and transmits the calculated results of the overturn rate and other important information to the display device using the CANOpen protocol. Also, in the calculation of the overturn ratio, the structure of the multi-purpose loader is similar to that of the crane belonging to the heavy equipment, and the crane overturn rate calculation method is used. Through this study, we can observe the condition of the heavy equipment and recognize the emergency situations such as abalone through the display device.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.4
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• pp.11-17
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• 2015

While most switching devices are based on PN junctions, a single layer can realize a switching device in the case of vanadium dioxide($VO_2$) thin films. In this paper, bidirectional current triggering(switching) is demonstrated in a two-terminal planar device based on a $VO_2$ thin film by illuminating the film with an infrared laser at 1550nm. To begin with, a two-terminal planar device, which had a $30{\mu}m$-wide $VO_2$ conducting layer and an electrode separation of $10{\mu}m$, was fabricated. A specific bias voltage range for stable bidirectional laser triggering was experimentally obtained by measuring the current-voltage characteristics of the fabricated device in a current-controlled mode. Then, by constructing a test circuit composed of the device, a standard resistor, and a DC voltage source, connected in series, the transient response of laser-triggered current and its response time were investigated with a DC bias voltage, included in the above specific bias voltage range, applied to the device. In the test circuit with a DC voltage source of 3.35V and a $10{\Omega}$ resistor, bidirectional laser triggering could be realized with a maximum on-state current of 15mA and a switching contrast of ~78.95.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.4
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• pp.165-170
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• 2016

The XLPE(or CV) cables installed to deliver high electric power from generator at the power station have operating for the last 40 years in Korea. In 6-8 years from the time of initial operation, the cables in operation start a deteriorating process, depending on the installation and usage conditions. Some cables, even before 6-8 years from the installation, can cause accidents due to the faulty construction or other inadequate environments. In order to prevent cable accident in advance, the regular auditing of power cables are required. For a systematic realization of surveillance and prevention of accidents, we have invented a measuring device. In this paper, we present the device installed at Korean Western Power Co. Ltd., in order to detect the deterioration status of insulation resistances of dielectrics in the cables. We present that the measured results by the device we developed show the deteriorating processes in the cables in operation.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.2
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• pp.206-214
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• 2017

In this study, measurement of thermophysical properties of materials at high temperatures was performed. This experiment employed a heater device to heat the material to a high temperature. The images of the specimen surface due to thermal load at various temperatures were recorded using charge-coupled device (CCD) cameras. Afterwards, the full-field thermal deformation of the specimen was determined using the digital image correlation (DIC) method. The capability and accuracy of the proposed technique are verified by two experiments: (1) thermal deformation and strain measurement of a stainless steel specimen that was heated to $590^{\circ}C$ and (2) thermal expansion and thermal contraction measurements of specimen in the process of heating and cooling. This research focused on two goals: first, obtaining the temperature dependence of the coefficient of thermal expansion, which can be used as data input for finite element simulation; and second, investigating the capability of the DIC method in measuring full-field thermal deformation and strain. The results of the measured coefficient of thermal expansion were close to the values available in the handbook. The measurement results were in good agreement with finite element method simulation results. The results reveal that DIC is an effective and accurate technique for measuring full-field high-temperature thermal strain in engineering fields such as aerospace engineering.

• Journal of IKEEE
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• v.14 no.3
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• pp.173-181
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• 2010

The high flowability performance evaluation device for the concrete is the device which was designed to compensate from the incorrect data detection of the viscosimetry examination of the existing concrete. As for the existing concrete viscosimetry method, the measuring data for a viscosity are very irregular by the point of view of an experimenter and a supervisor, Therefore there were some problems to have many different opinions by a small numerical value difference according to the job characteristic. In this paper, we suggested some mechanism to compensate the problem and some driving electronics including the related algorithm, and the communication structure with wireless sensor network between the devices and users are also presented. The effectiveness of the suggested method was verified with a real experiment.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.448-455
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• 2020

This study was carried out to investigate reduction of the frost damage using the mesh net used for the purpose of non-bagged cultivation. A device measuring the weight of frost was developed and installed in both the control and the experimental, and the effect of frost reduction was evaluated with their weights. As a result, weight of frost in the control was reduced from 37% to 59% with mesh net on the day the frost was observed. In addition, the device for automatically observing the amount of frost was developed and the height of the windbreak of the frost measuring device was determined to be 30 cm through wind tunnel experiment. The results of this study are expected to reduce frost damage during the flowering season of fruit trees by installing mesh net and it is expected to be used as basic data for agricultural use of mesh net.

• Korean Journal of Optics and Photonics
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• v.30 no.6
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• pp.237-242
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• 2019

A compact virtual-reality (VR) device with wider field of view provides users with a more realistic experience and comfortable fit, but VR lens distortion is inevitable, and the amount of distortion must be measured for correction. In this paper, we propose two different full-field distortion-measurement methods, considering the characteristics of the VR device. The first is the distortion-measurement method using multiple images based on camera calibration, which is a well-known technique for the correction of camera-lens distortion. The other is the distortion-measurement method by measuring lens distortion at multiple measurement points by rotating a camera. Our proposed methods are verified by measuring the lens distortion of Google Cardboard, as a representative sample of a commercial VR device, and comparing our measurement results to a simulation using the nominal values.

• Particle and aerosol research
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• v.10 no.1
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• pp.1-8
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• 2014

In this study, we have developed a real-time monitoring device for measuring $PM_{10/2.5/1}$ of ambient aerosol particles. The real-time PM (Particulate Matter) monitor was based on the light scattering method and had 16 channels in particle size. The laboratory and field tests were carried out to evaluate the performance of the PM monitor developed. Arizona Road Dust particles ranging from diameter of 0.1 to $20{\mu}m$ were generated as test particles in the laboratory test. The field test was carried out at the Seoul Meteorological Observatory. We can obtain the particle size and number concentration (particle size distribution) only from the real-time PM monitor developed. Therefore, the average density of aerosol particles was used to obtain the PM data from the particle size distribution. The $PM_{10/2.5/1}$ results of the PM monitor were compared with the data of the Grimm Dust Monitor (Model 1.108) and a beta ray gauge (Thermo Fisher Scientific). As a result, it was shown that the $PM_{10/2.5/1}$ results obtained by the real-time PM monitor agreed well with the data of the reference devices, and overall, the real-time PM monitor could be used as a PM monitoring device for real-time monitoring of the ambient particles.