• Korean Journal of Optics and Photonics
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• v.15 no.4
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• pp.349-354
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• 2004

As a transmitter sub-assembly in the XFP(10 Gb/s Small Form Factor Pluggable) transceiver module, a transmitter optical sub-assembly(TOSA) is designed, fabricated and characterized in view of electrical and thermal performances. For a low-cost and compact packaging TOSA, the bias-tee and the matching resistor are monolithically integrated on the AlN sub-mount and a newly designed coplanar waveguide is drawn in the TO-stem. All optoelectronic components packaged in the TOSA are modeled by the equivalent circuit, which helps to improve and characterize the TOSA performance. The fabricated TOSA shows the -3㏈ bandwidth as high as 11 GHz at an elevated temperature of 85$^{\circ}C$.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.510-513
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• 2016

Detecting of the object in image processing is substantial but it depends on the object itself and the environment. An object can be detected either by its shape or color. Color is an essential for pattern recognition and computer vision. It is an attractive feature because of its simplicity and its robustness to scale changes and to detect the positions of the object. Generally, color of an object depends on its characteristics of the perceiving eye and brain. Physically, objects can be said to have color because of the light leaving their surfaces. Here, we conducted experiment in the aquarium fish tank. Different color of fish robots are mimic the natural swim of fish. Unfortunately, in the underwater medium, the colors are modified by attenuation and difficult to identify the color for moving objects. We consider the fish motion as a moving object and coordinates are found at every instinct of the aquarium to detect the position of the fish robot using OpenCV color detection. In this paper, we proposed to identify the position of the fish robot by their color and use the position data to control the fish robot gathering in one point in the fish tank through serial communication using RF module. It was verified by the performance test of detecting the position of the fish robot.

• The Journal of the Korea Contents Association
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• v.9 no.3
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• pp.39-48
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• 2009

The Spectrum Sensing technology is the core technology of the Cognitive Radio (CR) system that is one of the future wireless communication technologies. This is the technology that temporarily allocates the frequency bandwidth by scanning surrounding wireless environments to keep licensed terminals and search the unused frequency bandwidth. In this paper, we implement the efficient Spectrum Sensing methods based on CR technology in an embedded board. The DVB-H signal with the 6MHz bandwidth is used as the RF input signal. And we confirm the Spectrum Sensing result using Modified Periodogram Method, Welch's Method, SCF Method. And also, We examine the execution speed of each of detailed functions and the performance of Spectrum Sensing methods on TI320C6416 DSP board inserted in an embedded board.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.3_1spc
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• pp.607-614
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• 2013

This paper proposes a robot driving system and sensor implementation for use with an education robot. This robot has multiple functions and was designed so that children could use it with interest and ease. The robot recognizes the location of a user and follows that user at a specific distance when the robot and user communicate with each other. In this work, the robot was designed and manufactured to evaluate its performance. In addition, an embedded board was installed with the purpose of communicating with a smart phone, and a camera mounted on the robot allowed it to monitor the environment. To allow the robot to follow a moving user, a set of sensors combined with an RF module and ultrasonic sensors were adopted to measure the distance between the user and the robot. With the help of this ultrasonic sensors arrangement, the location of the user couldbe identified in all directions, which allowed the robot to follow the moving user at the desired distance. Experiments were carried out to see how well the user's location could be recognized and to investigate how accurately the robot trackedthe user, which eventually yielded a satisfactory performance.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.231-231
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• 2012

7개 나라가 참여해서 공동으로 제작하고 있는 국제핵융합실험로(ITER)는 2020년경에 제작 설치가 완료될 예정이다. ITER 장치에는 6개의 시험 블랑켓 모듈(Test Blanket Module : TBM)이 장착될 예정이며, 그 중에서 한국도 1개를 독자적으로 제작해서 설치할 예정이다. 한국형 헬륨 냉각 고체형 증식(Helium Cooled Solid Breeder : HCSB) TBM이며, 한국은 ITER 참여국 중 유일하게 중성자 반사 재료를 채택한 것이 특징이다. 중성자 반사재료로는 지름 1 mm 내외의 흑연 페블에 SiC를 코팅해서 사용할 예정이다. SiC는 고온저방사화 물질로 차세대 핵융합로의 구조 재료로도 개발되고 있는 물질로, 이렇게 하면 흑연의 단점인 기계적 특성 향상뿐만 아니라, 산화나 화재 등에 대한 사고의 부담도 크게 줄일 수 있는 장점이 있다. 흑연위에 SiC를 코팅하는 방법은 여러 가지가 있으며, 그 중에서 비교적 간단한 건식 방법은 RF Sputtering, PECVD 등이 있다. 건식은 코팅방법이 간단하고 비교적 쉬운 편이지만 페블표면에 양질의 SiC 박막을 얻기가 쉽지 않은 단점이 있다. 이들 방법보다 습식법은 코팅이 까다롭지만 양질의 코팅막을 비교적 쉽게 얻을 수 있는 장점이 있다. CVD의 경우 전구체 물질로 여러 가지 물질이 사용될 수 있으며 대표적으로 $SiH_4$, $Si(CH_3)_4$, $CH_3SiCl_3$ 등이 있으며, 캐리어 가스로는 $H_2$가 사용된다. 이렇게 얻어진 SiC 코팅페블은 흑연에 비해 파괴강도도 향상되고 마모 등에 강한 것을 확인할 수 있었다.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.2
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• pp.234-242
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• 2002

In this research, a transmission control unit was developed for a wheel loader on the basis of 16-bit microcontroller system. The TCU has the basic functions which include shifting control algorithm, actuation of six proportional solenoid valves, signal conditioning for four speed sensors, remote data monitoring capability with RF-module and duty cycle identification system which could identify the duty cycles from PWM signals. In order to design the control system, the overall transmission structure of the wheel loader was investigated and its characteristics of shifting were analyzed in advance. For the purpose of identifying the existing control algorithm and acquire some information about the shifting performance, the shifting experiments were performed for various shifting conditions with the conventional TCU. From the previous work on the conventional TCU, the shifting scheme was designed with the open-loop control which is based on the experimental data only to verify the feasibility of the developing TCU's shilling capability. The experimental results show comparable shifting characteristics to that of conventional TCU though the tests were performed at restricted shilling conditions. Hence, we could have the confidence for the development of the wheel loader automatic transmission TCU and its shifting quality could be improved with the adoption of appropriate feedback control scheme.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.174.2-174.2
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• 2016

도금은 크게 전해 도금과 무전해 도금으로 나눌 수 있다. 전기적 에너지를 사용하여 이온 상태의 금속을 환원시켜 석출함으로써 도금을 진행하는 전해 도금과는 달리 무전해 도금은 도금액 내의 환원제에 의해 금속 이온을 환원시켜 도금을 진행한다. 무전해 도금법은 전해 도금에 비해 전류 인가 장비가 필요하지 않아 도금 공정이 간단하고, 피도금체에 따른 인가 전류, 전압, 금속의 환원 전위 등을 계산하지 않아도 되기 때문에 전문적인 지식이 없어도 도금을 할 수 있다. 하지만 무전해 도금은 도금이 진행 될수록 도금액 내 금속 이온, 환원제의 농도 등이 수시로 변화하기 때문에 도금액의 조성을 파악하여 원하는 두께의 도금층을 형성하는 방법에 대한 연구가 필요하다. 본 연구에서는 무전해 도금액 내 환원제, 도금액 온도, 도금 시간을 변경하여 Ni 무전해 도금을 형성 하였고 그 특성을 평가하였다. 도금은 각각 플라스틱, RF module 유리 등 다양한 기판에 진행 하였으며, 도금 후 밀착성, 도금 두께 및 microstructure를 분석하였다. 도금 후 밀착성을 분석하기 위해 열처리 후 박리정도를 테스트를 하였고, 도금 두께 및 microstructure를 분석하기 위해 field emission scanning electron microscope (FE-SEM), energy-dispersive spectroscopy (EDS)를 사용하였다. 실험 결과, 두께 $3{\sim}5{\mu}m$ 급의 균일한 도금층이 형성된 것을 확인하였으며, $260^{\circ}C$에서 3회 열처리 후 박리성 평가 결과, 결함 없는 양호한 표면을 나타내었다.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.6
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• pp.686-691
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• 2003

In the paper, an intelligent biped walking robot that can overcome the obstacle is developed. Walking algorithms are designed based on the analysis of the human's manner of walking. Infrared sensors are used to detect the obstacles in the working environment and the remote controller of the biped robot use a RF module. The experiment results show that the developed biped walking robot can perform the stable static walking, attention walking, rotation and side stepping to avoid the obstacle, and hurdling the obstacle using the distance correction algorithm that is designed based on the distance information between the biped robot and the obstacle.

• Journal of electromagnetic engineering and science
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• v.10 no.4
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• pp.316-321
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• 2010

This paper presents a novel fourth harmonic mixer with new structure. The traditional 3-ports fourth harmonic mixer and the novel fourth harmonic mixer are designed by ADS, HFSS and CST simulator. The mixers have been fabricated and tested. The size of the traditional 3-ports fourth harmonic mixer is $12{\times}15$ mm, and the best conversion loss is 18.7 dB according to the measurement. Since the traditional 3-port mixer size is too large to be ranked, we design a novel fourth harmonic mixer for imaging system. The width of the mixing module in the novel fourth harmonic mixer is only 3.65 mm, and this size is fully capable to meet the mixer unit space which is not greater than 5 mm. The simulation result shows that the mixer has good performance, and the experiment result shows that the best conversion loss of the novel fourth harmonic mixer is 16.3 dB at RF signal of 91.3 GHz.

• Journal of electromagnetic engineering and science
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• v.14 no.4
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• pp.321-328
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• 2014

Software defined radar (SDR) is a multi-purpose radar system where most of the hardware processing is performed by software. This paper introduces a concept and technology trends of software defined radar, and addresses the advantages and limitations of the current SDR radar systems. For the advanced SDR concept, the KAU SDR Model (KSM) is presented for the multimode and multiband radar system operating in S-, X-, and K-bands. This SDR consists of a replaceable multiband antenna and RF hardware, common digital processor module with multimode, and open software platform based on MATLAB and LabVIEW. The new concept of the SDR radar can be useful in various applications of the education, traffic monitoring and safety, security, and surveillance depending on the various radar environments.