• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.203-206
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• 2007

본 논문은 음성 IC를 사용한 다기능 어린이 영어 공부상 제품개발에 관한 것으로 (1) 영어의 알파벳 A~Z까지 26개의 다양한 캐릭터를 어린이 기호에 맞게 도안하여 어린이 정서에 효과가 있도록 하였다. (2) 캐릭터 상부면에 캐릭터를 터치(누름)하면 접속될 수 있도록 FPCB 스위치와 배선을 디자인 하였다. (3) A~Z까지 알파벳의 철자발음, 26개의 단어에 맞는 단어발음, 각각의 단어에 맞는 싸운드(소리), 그리고 3가지 기능에 대한 퀴즈형식의 원어민 발음을 녹음하였다. (4) 이렇게 구동될 수 있는 전자제어 장치를 설계하여 캐릭터를 터치(누름)하면 각각의 기능에 맞게 원어민 발음의 소리를 들으면서 영어학습을 하고 놀이를 할 수 있는 다기능 어린이 영어공부상 제품을 개발하였다.

• The Journal of Korean Society for Radiation Therapy
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• v.18 no.2
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• pp.81-87
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• 2006

Purpose: Few researches have been peformed on the dose distribution of the moving organ for radiotherapy so far. In order to simulate the organ motion caused by respiratory function, multipurpose phantom and moving device was used and dosimetric measurements for dose distribution of the moving organs were conducted in this study. The purpose of our study was to evaluate how dose distributions are changed due to respiratory motion. Materials and Methods: A multipurpose phantom and a moving device were developed for the measurement of the dose distribution of the moving organ due to respiratory function. Acryl chosen design of the phantom was considered the most obvious choice for phantom material. For construction of the phantom, we used acryl and cork with density of $1.14g/cm^3,\;0.32g/cm^3$ respectively. Acryl and cork slab in the phantom were used to simulate the normal organ and lung respectively. The moving phantom system was composed of moving device, moving control system, and acryl and cork phantom. Gafchromic film and EDR2 film were used to measure dose ditrbutions. The moving device system may be driven by two directional step motors and able to perform 2 dimensional movements (x, z axis), but only 1 dimensional movement(z axis) was used for this study. Results: Larger penumbra was shown in the cork phantom than in the acryl phantom. The dose profile and isodose curve of Gafchromic EBT film were not uniform since the film has small optical density responding to the dose. As the organ motion was increased, the blurrings in penumbra, flatness, and symmetry were increased. Most of measurements of dose distrbutions, Gafchromic EBT film has poor flatness and symmetry than EDR2 film, but both penumbra distributions were more or less comparable. Conclusion: The Gafchromic EBT film is more useful as it does not need development and more radiation dose could be exposed than EDR2 film without losing film characteristics. But as response of the optical density of Gafchromic EBT film to dose is low, beam profiles have more fluctuation at Gafchromic EBT. If the multipurpose phantom and moving device are used for treatment Q.A, and its corrections are made, treatment quality should be improved for the moving organs.

• Journal of the Korean Geosynthetics Society
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• v.11 no.4
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• pp.45-53
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• 2012

Ground drilling is a common method to conduct site investigation, soil improvement, and pile installation. In the point of construction ground drilling requires electrical energy to drill a hole in ground in which the energy exerts into the motor located on the head of auger and generates rotational power. In this paper it is verified that the exerted electrical energy is closely related to the strength characteristics of ground. Measurement sensors, recording system, and drilling system were developed to obtain exerted motor current and drilling depth and laboratory soil box tests were carried out. The measured motor current and boring depth were applied to predict SPT N-value and the prediction results were compared to SPT N-value of laboratory tests. The test results show that the exerted electrical energy to bore ground be a good index to estimate SPT N-value.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.411.2-411.2
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• 2016

직접 메탄올 연료전지 (DMFCs)는 친환경적이고 낮은 작동 온도로 인한 빠른 구동, 높은 에너지 밀도 등 다양한 장점을 가지고 있어 차세대 에너지 변환소자로 많은 관심을 받고 있다. 직접 메탄올 연료전지는 메탄올을 연료로 사용하며, 메탄올이 보유하고 있는 화학적 에너지를 전기 에너지로 변환하는 장치로써 음극에서는 백금 촉매로 인한 메탄올 산화반응, 양극에서는 환원 반응이 일어나며 전기화학적 구동을 하게 된다. 하지만 일산화탄소 피독으로 인한 촉매 활성 저하, 메탄올의 cross over, 백금 촉매 사용으로 인한 고비용 등의 문제점을 가지고 있다. 따라서 많은 연구자들이 백금 사용량을 줄이고 백금 촉매를 고르게 분포하기 위해 값이 저렴하고 넓은 비표면적을 갖는 탄소계 (graphite, graphene, carbon nanotube, carbon nanofiber 등) 지지체 재료를 도입하고 있다. 이 중 탄소나노섬유 (carbon nanofibers, CNFs)는 우수한 전기전도도와 열적/화학적 안정성을 가지고 있으며, 특히 넓은 비표면적을 가지고 있어 백금 촉매의 지지체로서 많은 연구가 진행되고 있다[1]. 따라서 우리는 전기방사법을 활용하여 넓은 비표면적을 보유하는 다공성 탄소나노섬유를 성공적으로 합성하였다. 또한, 이를 백금 촉매의 지지체로 도입하여 직접 메탄올 연료전지를 위한 다공성 탄소나노섬유에 담지된 고분산성 백금 촉매를 제조하였다. 제조한 다공성 탄소나노섬유의 형상 및 구조 분석은 주사전자 현미경 (field-emission scanning electron microscopy)와 투과전자 현미경 (transmission electron microscopy)를 이용하여 분석하였고, 결정구조와 화학적 결합상태는 X-선 회절분석 (X-ray diffraction) 및 X-선 광전자 분광법 (X-ray photoelectron spectroscopy)를 이용하여 규명하였다. 전기화학적 특성은 순환 전압 전류법 (cyclic voltammetry)를 이용하였다. 이러한 실험 결과들을 바탕으로 다공성 탄소나노섬유에 담지된 고분산성 백금 촉매의 자세한 특성을 본 학회에서 다루도록 하겠다.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.5
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• pp.79-86
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• 2009

Recently PMSM(Permanent magnet synchronous motor) are used for the various direct drive applications such as index table, telescope system and so on. Because the position/speed control performance of direct drive PMSM is directly affected by the torque ripple, there are lots of studies to reduce the cogging torque in the motor design stage. In order to verify the motor design, the reliable cogging torque measurement system is essentially required. The measured motor must be rotated in the constant speed under 1deg/sec so that the cogging torque profile is measured correctly. In this study, the cogging torque measurement system which uses the direct drive PMSM and the speed controller to rotate the measured motor in 0.1rpm(0.6deg/sec) has been developed. Simulink/xPC target was used for the controller and data acquisition system. Based on PI controller, DOB and AFC have been applied to eliminate the low frequency disturbances and the periodic speed ripple. The experimental results show the good performance of the speed regulation for the reference speed 0.1rpm and the reliable profile of the measured cogging torque by the developed speed controller.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.2
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• pp.97-104
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• 2011

This paper deals with the quick and precise disaster prevention automation system (DPAS) based on information communication technology (IT) that detects fire and disasters in the building automatically and quickly and then activates the facilities to extinguish fire and disasters, monitoring such situation in a real time through wire-wireless communication network. The proposed DPAS is applied a programmable logic controller (PLC) of one-chip type which is smallsize and lightweight and also has highly sensitive-precise reliabilities. The one-chip type PLC analyzes detected signals from sensors in a case of fire and disasters, then activates fire extinguishing facilities for rapid suppression. The detected data is also transferred to a remote situation room through wire-wireless network of RS232c and bluetooth communication. The transferred data sounds an emergency alarm signal, and operates a monitoring program. The proposed DPAS based on IT will minimize the life and wealth loss from rapid measures while prevents fire and disasters.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.492-498
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• 2016

It is well known that since abrupt faults in induction motors tend to lead to subsequent faults and deterioration of the drive apparatus, motor faults may lead to several operating restrictions, such as security problems and economic loss. A lot of research has been done in the area of diagnosis to detect machine faults and to prevent catastrophic hazards in the motor drive system. This paper presents a new method of motor current signature analysis in which the DC-link current of the inverter-driven induction motor system, where a single current sensor is employed instead of three AC current sensors, is measured, and fast Fourier transform analysis is performed. This proposed method makes it possible to easily discern and clearly separate the motor fault current signature from the normal operation current flowing through the stator and rotor windings.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.3
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• pp.121-127
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• 2020

The small tracking radar targets the target in a real-time, fast-moving, fast-moving target against aircraft with a large RCS that is maneuvering at low speed and a small RCS aircraft maneuvering at high speed (fighters, drones, helicopters, etc.) It is a pulsed radar that detects and tracks. Performing a performance test on a tracking radar in a real environment is expensive, and it is difficult to quantitatively measure performance in a real environment. Describes the composition of the laboratory environment's comprehensive performance test facility and the main requirements and implementation of each configuration.Anechoic chambers to simulate the room environment, simulation target generator to simulate the signal of the room target, target It is composed of a horn antenna driving device to simulate the movement of a vehicle and a Flight Motion Simulatior (FMS) to simulate the flight environment of a tracking radar, and each design and implementation has been described.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.251-257
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• 2014

An actuator system is a type of motor designed to control a mechanism operated by a source of energy, in the form of an electric current by converting energy into some kind of motion. As audio actuators, transforming electric voltage signal into audio signal, speakers and amplifiers are commonly used. In applications of industry, high output power systems are required. For these systems to generate high-quality output, it is essential to control output impedance of audio systems. We have developed an adaptable power supply for driving active amplifier systems with variable loads. Depending on the changing values of resistance of the speaker which produces audible sound by transforming electric voltage signal, the power supply source of the active amplifier can generate the maximum power delivered to the speaker by an adaptable change of loads. The amplifier is well protected from the abrupt increment of peak current and an excess of current flow.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.2
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• pp.493-503
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• 2000

There are two types of generators in the MHD generation : linear type Faraday and disk type hall generator. In this paper, it is experimented disk type hall generator. Disk type generator is driven by shock tube that compresses working gas isentropically in a very short time. As a working gas, helium gas seeded with cesium is used. it is difficult to confirm the whole condition thorough oかy experiment because the things happened in MHD generator is very complex. Furthermore we can't how exactly what happen at the inside of generator's channel because the time of generation is very short and working gas flows out very high speed. Expecially it is almost impossible to measure the things occurred in the boundary layer using MHD generation experimental equipment driven shock uk. With above reasons, to know certainly how the several values happened inside disk MHD generator charge, some graphs were drawn linearly through calculation using measured experimental data. For the more, other calculated results which can't be obtained by only experiment are considered in this paper. And these calculated results are compared to experiment data how exactly done the calculation.