• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.6
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• pp.453-460
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• 2017

High voltage power transmission lines have been to keep the proper dip for maintenance. Powerline dips at a random point are conventionally measured by the direct or indirect observation but it is not only unsafe but labor-intensive. Therefore in this study we applied the photogrammetric technique to remotely measure the powerline dips. Since it is not easy to extract conjugate points from linear powerlines, we exploited the epipolar lines acrossing the powerlines for 3D mapping of the powerlines and dip measurements. The vertical mapping accuracy estimated at two field-surveyed power line points was 15~16cm that are within 5% of deflection at the points and less than 3% of the powerline dip.

• Korean Journal of Materials Research
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• v.22 no.3
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• pp.155-158
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• 2012

In this work, AlON-$Al_2O_3$ coatings were prepared on Al2021 alloy by the electrolytic plasma processing (EPP) method. The experimental electrolytes include: 2 g/l NaOH as the electrolytic conductive agent, 10 g/l $Na_2AlO_2$ as the alumina formative agent, and 0.5 g/l $NaNO_2$, $NaNO_3$, and $NH_4NO_3$ as the nitride inducing agents. The effects of different nitrogen inducing agents were studied by a combined compositional and structural analyses of the ceramic coatings carried out by Xray diffractometry (XRD) and scanning electron microscopy (SEM) for the specimens EPP-treated at room temperature for 15 min under a hybrid voltage of 260 DC along with an AC 50 Hz power supply (200 V). Microhardness tests and wear tests were carried out to correlate the evolution of the microstructure and the resulting mechanical properties. Potentiodynamic polarizations and immersion corrosion tests were carried out in 3.5wt% NaCl water solutions under static conditions in order to evaluate the corrosion behavior of the coated samples. The results demonstrate that $NaNO_2$ is proven to be a good nitrogen inducing agent to produce high quality AlON-$Al_2O_3$ ceramic coatings.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1302-1307
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• 2011

The Spiral coil is made considering primary, secondary side coil inductance, turn number, size, thickness, and shielding area with the litz wire-type in case of manufacturing a coil, and at this time, the semi-automation winding machine is used. When deciding on primary and secondary side coil specification and manufacturing a coil, the spiral coil of a specification varied in the various litz wire of a specification is required, and at this time, a difficulty is generated by the manufacture cost, period which during, and failure the manufacture is generated in the coil sample making. A difficulty is in the desired coil quality control of a specification. Since improving the rectifier of the secondary side in order to improve this kind of problem, the range of the coil design and the during the manufacture, various coil manufacture specifications can be comprehensively made.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.10
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• pp.166-175
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• 2007

Nowadays, the power quality issue becomes very important in the electric distribution system. Especially, when a distribution transformer is replaced, the customers who are supplied electricity from the transformer feel inconvenience due to electric outage. Therefore, an advanced method for the distribution transformer replacement without outage is strongly required. The conventional method is the primary-secondary high voltage bypass method according to the transformer utilization factor and the field condition. But it is inconvenient and has some problems such as breakdown and security troubles of the workers according to the unauthorized and temporary work. Therefore, the new scheme for the replacement with uninterruptable power supply is demanded. This paper proposes the new replacement method using the phase converter. The proposed method can reduces the process of replacement work and also ensures worker's safety. Therefore, the method is reasonable in comparison with the conventional method. The proposed method is able to contribute the national economy growth and elevate the convenience of national life by uninterruptable power supply.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.5
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• pp.857-864
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• 2020

The multi-functional VoIP phone supports the Ethernet protocol in the TIPS(: Tactical IP Switch), which is one of the sub-systems of the tactical information and communication system (TICN). It provides secured voice / video calls in conjunction with VoIP exchanges and supports differential services such as multi-party calls and command functions. In this paper, improving methods have been proposed to reduce power supply defects in the field of multi-functional VoIP phones. The power supply part was improved by applying TVS of the output voltage inlet of the dedicated adapter of the multi-functional VoIP phone, TVS of the PoE module input, adding blocking diodes, and adding DC / DC converters behind the poly-switch. Also, functional and environmental tests were performed to verify the validity of the proposed methods.

• Journal of the Korean Institute of Gas
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• v.11 no.1 s.34
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• pp.40-45
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• 2007

This paper describes NDIR $CO_{2}$ gas sensor that shows the characteristics of temperature compensation. It consists of novel optical cavity that has two elliptical mirrors and a thermopile that includes ASIC chip in the same metal package for the amplification of detector output voltage and temperature sensor. The newly developed sensor module shows high accuracy ($less\;than {\pm}40\;ppm$) throughout the measuring concentration of $CO_{2}$ gas from 0 ppm to 2,000 ppm. After implementing the calculation methods of gas concentration, which is based upon the experimental results, the sensor module shows high accuracy less than ${\pm}5\;ppm$ error throughout the measuring temperature range ($15^{\circ}C\;to\;35$^{\circ}C$) and gas concentrations with self-temperature compensation.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.8
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• pp.475-481
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• 2005

In the existing ICT technique, the mounted electronic devices on the printed circuit board are tested whether the devices are good or not by comparing and measuring the value of the devices after separating the devices to be tested from around it based on the guarding method. But, in case that resistance, inductor and capacitor are configured as a parallel circuit on the circuit pattern, values for each device can not be measured because the total impedance value of the parallel circuit is measured. Accordingly, it is impossible to test whether the parallel circuit is good or not in case that the measured impedance value is within the tolerance error. Also, it is difficult to identify that which device among R, L and C of the parallel circuit is bad in case that the measured impedance value is out of the tolerance error. Accordingly, this paper proposes a test method which can enhance the quality and productivity by separating and measuring accurately R, L and C components from the RLC parallel circuits on the device-mounted printed circuit board. First, the RLC parallel circuit to be test is separated electrically from around it using three-terminal guarding technique. And then R, L and C values are computed based on the total impedance values and phase angles between voltage and current of the parallel circuit measured from two AC input signals with other frequency, Finally, the availability and accuracy of the proposed test method is verified by reviewing the simulation results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.10
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• pp.1795-1803
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• 2011

Advanced Metering Infrastructure (AMI) is one of the important components to form a smart-gird, which is an advanced power system by combining the power system with the communication systems. This AMI makes it possible to exchange information between operators and consumers for the efficient and reliable operation of the power system through a smart meter or a In-Home Display. However, according to the increase of the demanded information such as the power quality, the accurate load-profile, and the billing data to help customers manage their power consumption, it is necessary to gather more accurate analytical data from each house appliances and transfer it to the smart meter for synthesizing the information and controlling each loads. In this paper, the development of the wireless data acquisition device for the individual load data metering, which is connected with the smart meter for advanced functions, is proposed. AVR, a kind of microcontroller, and Bluetooth are used and integrated into the proposed the wireless data acquisition device to transmit the detailed power data (voltage and current) to the smart meter. To verify the effectiveness of the proposed system, a hardware experiment is carried out including the confirmation of the possibility for providing the more various information by applying analysis algorithms to the obtained data. Also, the application structure of the wireless data acquisition device to gather the data from the various house appliances is presented.

• Journal of the Korean Society of Radiology
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• v.12 no.3
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• pp.289-295
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• 2018

Most diagnostic devices in the medical field use X-ray sources, which emit energy spectra. In radiological diagnosis, the quantitative and qualitative analyses of X-rays are essential for maintaining the image quality and minimizing the radiation dose to patients. This work aims to obtain the X-ray energy spectra used in diagnostic imaging by Monte Carlo simulation. Various X-ray spectra are simulated using a Monte Carlo simulation tool. These spectra are then compared to the reference data obtained with a tungsten anode spectral model using the interpolating polynomial (TASMIP) code. The X-ray tube voltages used are 50, 60, 80, 100, and 110 kV, respectively. CdTe and a-Se detector are used as the detectors for obtaining the X-ray spectra. Simulation results demonstrate that the various X-ray spectra are well matched with the reference data. Based on the simulation results, an appropriate X-ray spectrum, in accordance with the tube voltage, can be selected when generating an image for diagnostic imaging. The dose to be delivered to the patient can be predicted prior to examination in the diagnostic field.

• Journal of Sensor Science and Technology
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• v.29 no.5
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• pp.354-359
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• 2020

The high vacuum hermetic sealing technique ensures excellent performance of MEMS resonators. For the high vacuum hermetic sealing, the customization of anodic bonding equipment was conducted for the glass/Si/glass triple-stack anodic bonding process. Figure 1 presents the schematic of the MEMS resonator with triple-stack high-vacuum anodic bonding. The anodic bonding process for vacuum sealing was performed with the chamber pressure lower than 5 × 10^-6 mbar, the piston pressure of 5 kN, and the applied voltage was 1 kV. The process temperature during anodic bonding was 400 ℃. To maintain the vacuum condition of the glass cavity, a getter material, such as a titanium thin film, was deposited. The getter materials was active at the 400 ℃ during the anodic bonding process. To read out the electrical signals from the Si resonator, a vertical feed-through was applied by using through glass via (TGV) which is formed by sandblasting technique of cap glass wafer. The aluminum electrodes was conformally deposited on the via-hole structure of cap glass. The TGV process provides reliable electrical interconnection between Si resonator and aluminum electrodes on the cap glass without leakage or electrical disconnection through the TGV. The fabricated MEMS resonator with proposed vacuum packaging using three-layer anodic bonding process has resonance frequency and quality factor of about 16 kHz and more than 40,000, respectively.