• Journal of the Korean Vacuum Society
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• v.22 no.4
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• pp.175-180
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• 2013

We developed the contamination prevention module of an optical window for an In-Situ Particle Monitor (ISPM) system. the core part of the module is the generator of an ultrasonic wave and the module is to remove particles stuck to the window by the transfer of the wave force to the window surface. In order to enhance transfer efficiency of the waves the frequency of the ultrasonic wave was optimized and a low impedance material (plexiglass) and a soft sealing material (Si rubber) were used. The ISPM with the developed module was installed at the exhaust line of a BPSG CVD equipment and the effect of the module was verified.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.711-717
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• 2017

Startability and harmful emissions are the main issues in diesel engine development under cold conditions. The characteristics of combustion with multiple injection were investigated under cold start conditions. For quantitative analysis, the in-chamber pressure profile was measured and combustion visualization using direct imaging was accomplished. With multiple injection, the peak in-chamber pressure and heat release rate were increased compared to single injection. In addition, the period of flame luminosity detection was shortened using multiple injection. Combustion by main injection was improved with an increase in heat released by pilot combustion when the pilot injection quantity was increased. Finally, an increase in injection pressure also showed the possibility of combustion improvement. On the other hand, an increase of in the pilot injection quantity and injection pressure can cause an increase in harmful emissions, such as HC and CO due to wall wetting. Therefore, more sensitive calibration will be needed when applying a multiple injection strategy under cold start conditions.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.7
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• pp.93-99
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• 2015

In this paper, we propose a gaze correction method for realistic video teleconferencing. Typically, cameras used in teleconferencing are installed at the side of the display monitor, but not in the center of the monitor. This system makes it too difficult for users to contact each eyes. Therefore, eys contact is the most important in the immersive videoconferencing. In the proposed method, we use the stereo camera and the depth camera to correct the eye contact. The depth camera is the kinect camera, which is the relatively cheap price, and estimate the depth information efficiently. However, the kinect camera has some inherent disadvantages. Therefore, we fuse the kinect camera with stereo camera to compensate the disadvantages of the kinect camera. Consecutively, for the gaze-corrected image, view synthesis is performed by 3D warping according to the depth information. Experimental results verify that the proposed system is effective in generating natural gaze-corrected images.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.123-123
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• 2016

만곡부, 합류부 등의 복잡한 지형을 갖는 자연하천에서의 오염물의 혼합 거동에 대한 이해는 수자원의 관리에 있어서 매우 중요하다. 특히 하폐수처리장과 같은 처리시설의 방류수와 같이 연속적으로 유입되는 오염물의 경우 하천 생태계에 지속적인 영향을 끼치며, 이러한 방류수는 대부분 지류를 통해 본류로 유입되게 된다. 이러한 오염물질이 지류로부터 본류로 합류되는 초기구간(near-field)의 경우, 횡방향 및 연직방향의 혼합 거동에 대한 상세한 분석이 필요하다. 본 연구에서는 금호강과 진천천이 좌안으로부터 합류되는 낙동강 중류 구간에서의 초기 혼합 구간의 연구를 위하여 전기전도도(electrical conductivity: EC)를 이용한 농도 추적 실험을 수행하였다. 수온, 전기전도도, 이온화 물질 등과 같은 자연 추적자(natural tracers)를 이용하는 농도 추적 실험은 인공추적자 물질을 이용한 실험을 대체할 수 있는 방안으로서, 기존 추적자 실험과 비교하여 경제적, 환경적인 효과와 하폭이 넓은 중규모 이상의 하천에서도 수행할 수 있다는 장점을 가지고 있다. 실험 구간에서 합류되는 2개의 지류 모두 인근 하폐수처리장으로부터 방류수가 연속적으로 유입된다. 본류에서 정해진 측선을 따라 센서가 설치된 보트를 이용하여 실시간으로 농도, 수리량 데이터를 GPS 위치 데이터와 함께 취득하였다. 실험 수행 결과, 지류인 금호강과 진천천의 EC 농도가 합류 전 낙동강 본류의 EC 기저농도보다 더 높은 값을 나타내었다. 이후 지류가 합류된 직후의 측선에서 측정한 EC 농도분포를 분석한 결과, 연직방향의 편차가 크게 나타나는 것으로 나타났으며 특히 유량이 낮을수록 연직 방향 편차가 커지는 경향을 보였다. 전반적으로 수심이 깊은 구간의 저층부로 갈수록 전기전도도의 값이 증가하는 경향을 나타났으며 흐름방향으로 진행됨에 따라 연직 편차가 줄어드는 경향을 보였다. 횡방향 혼합의 경우 지류의 유입으로 인하여 본류 좌안 쪽에서 전기전도도의 값의 상승을 확인할 수 있었으며 하류로 이동할수록 불균등했던 전기전도도의 분포가 횡방향 혼합을 통하여 균등한 분포로 전환되는 것으로 나타났다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.355-358
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• 2009

Due to growth of electronics and control devices, automation and situational awareness systems have been applied by automobile. Vision systems with the introduction of unmanned system being actively developed, but are still high price and visual information is passed through the cable, because of cars are difficult to install. In this paper, can be installed inside the car at low-cost, simple image processing device through a wireless communication know the obstacles and the alarm system based on Zigbee wireless communication, infrared and ultrasonic sensors to monitor the situation through with easy parking cars outside the system design was implemented.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.629-632
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• 2009

The interactive art and design can be interpreted as an intelligent system in the aspect of engineering. Because this information is treated and analyzed in real time and then such results is expressed in various media such as image, graphic, sound and etc. after these information are input through the sensor, camera and etc., for the efficient communication between human and production, namely, to communicate the interactive reaction, The image utilizing such interactive is being gradually developed as it widens its region in various art design fields. This research is purposed to make the system, which lets the citizens contact the information naturally by mixing the information for the environment with the interactive art of the arty type, and which lets the citizens feel the surrounding environment directly. This research will construct the live mood in the space itself and is utilized for the public art that can be directly experienced. It can provide the experience in the participation type that acquires the information being harmonized with the human naturally in the more developed type than the concept of the existing static installation. Therefore, it is sincerely required to research the interactive art in utilizing the public design.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.381-384
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• 2011

Wave drag reduction due to the repetitive laser induced energy deposition over a flat-nosed cylinder is experimentally conducted in this study. Irradiated laser pulses are focused by a convex lens installed in side of the in-draft wind tunnel of Mach 1.94. The maximum frequency of the energy deposition is limited up to 80. Time-averaged drag force is measured using a low friction piston which was backed by a load cell in a cavity as a controlled pressure. Stagnation pressure history, which is measured at the nose of the model, is synchronized with corresponding sequential schlieren images. With cylinder model, amount of drag reduction is linearly increased with input laser power. The power gain only depends upon the pulse energy. A drag reduction about 21% which corresponds to power gain of energy deposition of approximately 10 was obtained.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.4
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• pp.12-17
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• 2018

A natural cavitation-type high-speed underwater vehicle with solid rocket motor is tested, and its speed and running distance are measured. The outputs from pressure sensors on the surface of the vehicle reveal a pressure-time history reflecting the development of supercavitation. Underwater cameras installed on the wall of the test pool record the entire process from the onset of supercavitation to its full development. CNU-SuperCT, based on two-dimensional inviscid theoretical analysis, is used to simulate test results. Considering CNU-SuperCT does not include the control fins of the vehicle, simulation results agree with test results very well. Additionally, pictures from underwater cameras support the test results.

• Korean Journal of Optics and Photonics
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• v.22 no.3
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• pp.151-158
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• 2011

This paper reports design and demonstration of optical systems for reflective-type remote optical displacement sensors. Optical systems for light illumination sources and a position sensitive detector (PSD) for the displacement sensor were developed to sense displacement of bridges and instability of skyscrapers in a distance range from 10 m to 250 m to an accuracy better than a few mm. Performance of the optical systems was verified by composing a displacement sensor and by using it in measurement of displacement of a remote target with proper reflective optics depending on distance. The displacement sensor was composed of two LED light sources, each with collimating optics, and a two-dimensional PSD with telescope-type optics. Its displacement resolutions was measured to be 0.1 mm at a distance of 10 m and less than 3 mm at a distance of 250 m.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.1163-1175
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• 2021

In autonomous driving, road markings are an essential element for object tracking, path planning and they are able to provide important information for localization. This paper presents an approach to update and measure road surface markers with HD maps as well as matching using inverse perspective mapping. The IPM removes perspective effects from the vehicle's front camera image and remaps them to the 2D domain to create a bird-view region to fit with HD map regions. In addition, letters and arrows such as stop lines, crosswalks, dotted lines, and straight lines are recognized and compared to objects on the HD map to determine whether they are updated. The localization of a newly installed object can be obtained by referring to the measurement value of the surrounding object on the HD map. Therefore, we are able to obtain high accuracy update results with very low computational costs and low-cost cameras and GNSS/INS sensors alone.