• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.5
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• pp.201-206
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• 2018

This study investigated the changes in pore water quality of polluted sediment by mixing ratio of granulated coal ash. The mesocosm experiments were carried out with 0%, 10%, 30% and 50%, respectively, of the material mixture ratio relative to the sediments. According to the results of the experiments, pH increased depending on the mixing ratio. Phosphate and ammonia concentrations were significantly decreased in the mixing ratio of 30% and 50% compared to the control (p < 0.05). The concentration of hydrogen sulfide was reduced by 72% at the mixing ratio of 10%, and it was not detected at the mixing ratio of 30% and 50%. This study was confirmed that granulated coal ash can change the pore water quality of polluted sediments in proportion to the amount of material. However, the effect of the mixing ratio between 30% and 50% was not significantly different, thus it is concluded that mixing of 30% of the volume of the sediment is economically feasible.

• Aerospace Engineering and Technology
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• v.4 no.1
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• pp.86-94
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• 2005

This paper shows the results of design, analysis, manufacturing and test performed to develop the CTU(Command Telemetry Unit) EQM(Engineering Qualification Model). According to the key requirement specifications, the logics and circuits of each board are designed. In order to validate designs, some worst case, part stress, reliability, FMECA, radiation environment and launch environment analyses are performed. After manufacturing and assembling all boards, all functions of CTU EQM are verified through the functional test, environmental test and ETB test.

• 대한공업교육학회지
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• v.45 no.2
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• pp.1-20
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• 2020

The purpose of this study is to develop an assembly-type liquid level control experimental equipment and a hands-on activity task that can be applied to the class so that students studying the chemical industry can easily understand the liquid level control. For this purpose, the content elements related to liquid level control in the chemical industry practice course of the 2015 revised curriculum was analyzed, a hands-on activity task with an assembly-type liquid level control experimental equipment was and developed. And then, expert verification was also performed and the hands-on activity task was applied to 19 students of S meister high school. The results obtained through this are as follows. First, the existing completion-type liquid level control experimental equipment was explored, and based on this, a new assembly-type liquid level control experimental equipment that can be assembled by students and used for practices was designed and manufactured. Second. by analyzing the contents of the NCS-based 'Chemical Process Maintenance Operation' practical course of the 2015 revised curriculum, learning contents related to level control were extracted. Among the contents related to the level control, the practice with understanding the process flow chart, manufacturing the level control experimental equipment, measuring the flow rate, and checking the level control phenomenon were conducted with the assembly-type liquid level control experimental equipment to systematically learn the level control.

• Korean Journal of Optics and Photonics
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• v.16 no.6
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• pp.521-526
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• 2005

We assembled the optical beam director with diameter 300 mm. This consists of primary, secondary mirrors and 5 folding mirrors. Among them, the primary mirror is the most important component so that we measure any possible deformation on it at every step of assembly. Also, we developed the systematic alignment algorithm, which is essential because the number of mirrors is 7. The final wavefront error of the system is 1.9 wave rms (wave=633 nm) which is 7 times larger than we expected. The main source is the deformation of the 131ding mirrors. We expect that what we have learned from the assembly of this system would be helpful when we deal with a larger system in the future.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04c
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• pp.118-120
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• 2003

컴포넌트 기반 개발 방법은 조립 가능한 컴포넌트들을 이용하여 소프트웨어를 구현하는 기술로써, 소프트웨어의 생산성 및 품질을 높이는 효과적인 방법으로 알려져 있다. 향후 성장이 예상되는 컴포넌트 시장에서는 여러 컴포넌트 공급자들에 의해 COTS나 Web Services의 형태로 동일 내지는 유사 기능을 수행하는 대체 가능한 컴포넌트들이 나타나게 될 것이다. 개발되는 컴포넌트 기반 소프트웨어의 품질을 위해서는 여러 경쟁 컴포넌트들 중에서 우수한 성능을 가진 컴포넌트를 선택하는 기술이 중요한 요소의 하나라고 할 수 있다. 일반적으로 컴포넌트는 컴포넌트 모델에 종속적이기 때문에 컴포넌트의 성능 측정기도 측정 대상 컴포넌트뿐만 아니라 컴포넌트 모델에 종속적으로 구현된다. 본 논문은 컴포넌트 모델과 미들웨어 프레임워크에 중립적인 분산 컴포넌트의 성능 측정 모델에 대하여 설명한다. 이 모델을 이용하여 컴포넌트 모델에 중립 적인 성능측정기를 개발할 수 있으며 컴포넌트의 비교와 검증에 필요한 객관적인 성능 측정 결과를 얻을 수 있다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.9
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• pp.685-697
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• 2017

In this paper, it is presented the result of design and fabrication for C-band solid state high power amplifier unit and components using in search radar. The solid state power amplifier(SSPA) assembly was fabricated using GaN(Gallium Nitride), which is semiconductor device, and the transmit signal output power of the solid state high power amplifier unit is generated by combining the transmit signal power of the solid state power amplifier configured in parallel through a design and fabricated waveguide type transmit signal combine assembler. Designed solid state high power amplifier unit demonstrated C-band 500 MHz bandwidth, maximum 10.5% duty cycle, transmit pulse width from $0.0{\mu}s{\sim}000{\mu}s$, and transmit signal power is 44.98 kW(76.53 dBm).

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.1
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• pp.69-76
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• 2005

The purpose of this study was to establish the accuracy of the industrial photogrammetry system constructed with INCA2 metric camera and V-STARS system on steel box girder measurement under industrial measurement condition. The objective of the measurement was to determine the distances of plane to plane or plane to libs, precise positions of the bolt holes and angles of the plane to plane on the steel box girder using coded targets, tape targets, edge targets and target adapters. The measurement undertaken has shown that industrial photogrammetry method were a very accurate and more importantly were produced quickly to measure the steel box girder.

• Journal of Preventive Medicine and Public Health
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• v.29 no.4 s.55
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• pp.785-799
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• 1996

We investigated the 1,004 workers who worked in a automobile factory to study the epidemiologic characterists of dermatoses due to cutting oils. Among the workers, 667(66.4%) answered the questionaire. They are belong to 5 departments of the factory-the Engine-Work(258 workers), Gasoline engine Assembly(210), Diesel engine Assembly(96), Power train Work(86), Power train Assembly(17). We measured the oil mist concentration in air of the departments and examined the workers who had dermatologic symptoms. The results were follows; 1) Oil mist concentration ; Of all measured points(52),9 points(17.2%) exeeded $5mg/m^3$- the time-weighed PEL-and one department had a upper confidence limit(95%) higher than $5mg/m^3$. 2) Dermatologists examined 213 workers. 172 of them complained any skin symptoms at that time - itching(32.5%), papule(21.6%), scale(15.7%), vesicle(12.5%) in order. The abnormal skin site found by dermatologist were palm(29.3%), finger & nail(24.6%), forearm(16.2%), back of hand(8.4%) in order. 3) As the result of physical examination, we found that 160 workers had skin diseases. Contact dermatitis was the most common; 69 workers had contact dermatitis alone(43.1%), 11 had contact dermatitis with acne(6.9%), 10 had contact dermatitis with folliculitis(6.3%), 1 had contact dermatitis with acne & folliculitis, and 1 had contact dermatitis with abnormal pigmentation. Others were folliculitis(9 workers, 5.6%), acne(8, 5.0%), folliculitis & acne (2, 1.2%), keratosis(1, 0.6%), abnormal pigmentation (1, 0.6%), and non-specific hand eczema (47, 29.3%). 4) The prevalence of any skin diseases was 34.0 pet 100 in cutting oil users, and 13.3 per 100 in non- users. Especially, the prevalence of contact dermatitis was 23.0 per 100 in cutting oil users and 23.0 per 100 in non-users. 5) We tried patch test(standard serise, oil serise, organic solvents) on 49 patients to differentiate allergic contact dermatitis from irritant contact dermatitis and found 20 were positive. 6) In a multivariate analysis(independant=age, tenure, kinds of cutting oil), the risk of skin diseases was higher in the water-based cutting oil user and both oil user than non-user or neat oil user(odds ratio were 2.16 and 2.78, respectively). And the risk of contact dermatitis was much higher at the same groups(odds ratio were 5.16 and 6.82, respectively).

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.172.2-172.2
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• 2012

위성은 발사 후 임무수행을 위하여 자세획득 및 자세결정이 필수적이다. 저궤도 위성에서 자이로센서는 별 센서와 함께 사용되거나, 별 추적기와 사용하여 자세의 변화량을 읽고 자세제어를 수행한다. 자이로센서는 크게 전력공급부와 각속도 측정부, 그리고 전자처리부 등으로 구성된다. 위성은 발사 전 조립시험 기간 동안 전자파, 진동, 열/진공 등의 환경시험 통하여 수차례의 성능 유무를 확인한다. 본고에서는 열진공시험 전과 후, 그리고 열진공시험 진행중에 측정한 결과를 통하여, 시스템적인 측면에서의 자이로센서 건강상태 및 성능을 분석하였다. 위성시스템 상태의 자이로 시험은 자이로센서가 가질 수 있는 조합에 따라 위성의 방향에 따른 지구각속도를 확인 및 관련 데이터를 분석하였다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1995.06a
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• pp.1-10
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• 1995

베어링은 상대운동을 지지하거나 안내하는데 사용되는 부품으로 이의 특성은 원활하게 회전(또는 운동)할 수 있어야 하며 이와 관련된 내구성이 우수해야 하고 또한 신뢰성이 높아야 한다는 것이다. 원활한 회전을 하기위해서는 정밀도 높은 진원가공을 할 수 있어야 하며 이 특성은 베어링이 양산품 이라는 관점에서 경제성있는 생산을 해내야 하는 요구조선이 있다. 양산가공 기술로는 궤도륜에 해당하는 것으로 단조, 전조, 선삭, 연삭 가공기술이 있으며, 부품과 관련해서는 압출, 압조, 사출 가공기술이 있다. 이와 맞물려 양산 조립기술, 공작기계 제작 보수 기술, 정밀 측정기술이 필요하다고 하겠다.