• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1996년도 추계학술대회 논문
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• pp.91-95
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• 1996

One must observe abrasive grain of grinding wheel and know their behaviors to understand the grinding mechanism. The behaviors of abrasive grain on the wheel surface. such as shapes distributions and changes were studied to make the grinding mechanism clear but the behaviors of abrasive grains on CBN wheel are not known enough. From this paper the working surface of a grinding wheel is observed by photography in which a picture of a wheel surface is taken by the camera through the microscope on the grinding machine and analyzed with the computer.

• 대한의용생체공학회:의공학회지
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• 제28권2호
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• pp.265-270
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• 2007

Polarization imaging systems have been widely used to selectively characterize skin lesions. Nevertheless, current systems are used in single-mode due to the limitations of a fixed polarization mode and a single-working distance of light source, in which uniform light distribution is achieved on target area. To address such limitations, we developed a variable polarization imaging system based on multi-working distance of light source for various clinical diagnoses. In this study, we characterize the imaging system and present experiment results demonstrating its clinical usefulness. The imaging system consists of a CCD color camera, linear polarization filters, and a single-layered LED ring light source which provides uniform light distribution at multi-working distances. The first polarizer was placed on the light source and the second polarizer placed on objective lens provides continuous linear polarization angle from $0^{\circ}\;to\;90^{\circ}$. The clinical efficacy of the imaging system was investigated by acquiring and analyzing clinical images of skin wrinkle and dental plaque. With the experiments, we verified the potential usefulness of the imaging system for other clinical applications.

• 대한기계학회논문집B
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• 제28권12호
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• pp.1475-1483
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• 2004

Loop thermosyphon(LTS) has many good characteristics such as low thermal resistance, no power consumption, noiseless operation and small size. To investigate the overall performance of LTS, we have performed various experiments varying three parameters: input power of the heater, working fluid(water, ethanol, FC3283) and filling ratio of the working fluid. At a combination of these parameters, temperature measurements are made at many locations of the LTS. The temperature difference between the evaporator and the condenser is used to obtain the thermal resistance. In addition, flow visualization using a high speed camera is carried out. The thermal resistance is not constant. It is lower at higher input power, which is one of the distinct merits of LTS. Flow instabilities are frequently observed when changing the working fluid, the input power and the filling ratio. The results show that the LTS can be readily put into practical use. Future practical application in electronic cooling is recommended.

• 한국직업건강간호학회지
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• 제11권2호
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• pp.121-131
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• 2002

Objective: The purpose of this study was to determine the physical load by identifying harmfully working postures and to develop recommendations for improving the existing situation with nurses in ICU, thereby to provide the basis for development of work-related musculoskeletal preventive program. Method: Various types of tasks were recorded with a video camera to chart and analyze different postures by OWAS(Ovako Working Posture Analysing System). Collected data showed that poor postures were adopted, not only for lifting or repositoning a patient, but also for other tasks. Data Analysis: The performed activities were then divided into Nursing Intervention Classification. Altogether 128 postures were selected for analysis. Then they were classified into different OAC (OWAS Action Categories). From all the observation, unhealthy postures, for which corrective measures had to be considered immediately (i.e., 75% classified as OACII+III+IV) were found. Collected data were analyzed in terms of percentage, 2-tail Mann-Whitney U test. Result: Poor postures mainly occur during 'positioning the patient' and 'airway suctioning' in NIC. No difference was found (p=0.060) between the percentage of harmful posture adopted during the patient handling tasks and non-patient handling tasks. Conclusion: This study shows, that in the nursing profession with ICU not only occur during patient handling, but also during other activities. The OWAS method was useful in determining the physical load by locating potential activities due to harmfully working postures, providing a detailed description with analysis, and suggesting successful means to reduce postural load.

• Journal of Mechanical Science and Technology
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• 제17권10호
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• pp.1507-1519
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• 2003

The two-phase flow patterns for both non-loop and loop type oscillating capillary tube heat pipes (OCHPs) were presented in this study. The detailed flow patterns were recorded by a high-speed digital camera for each experimental condition to understand exactly the operation mechanism of the OCHP. The design and operation conditions of the OCHP such as turn number, working fluid, and heat flux were varied. The experimental results showed that the representative flow pattern in the evaporating section of the OCHP was the oscillation of liquid slugs and vapor plugs based on the generation and growth of bubbles by nucleate boiling. As the oscillation of liquid slugs and vapor plugs was very speedy, the flow pattern changed from the capillary slug flow to a pseudo slug flow near the annular flow. The flow of short vapor-liquid slug-train units was the flow pattern in the adiabatic section. In the condensing section, it was the oscillation of liquid slugs and vapor plugs and the circulation of working fluid. The oscillation flow in the loop type OCHP was more active than that in the non-loop type OCHP due to the circulation of working fluid in the OCHP. When the turn number of the OCHP was increased, the oscillation and circulation of working fluid was more active as well as forming the oscillation wave of long liquid slugs and vapor plugs in the OCHP. The oscillation flow of R-142b as the working fluid was more active than that of ethanol and the high efficiency of the heat transfer performance of R -142b was achieved.

• 한국수소및신에너지학회논문집
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• 제28권1호
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• pp.106-112
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• 2017

The present study describes flow induced noise generated from a ball valve used for a gas pipeline. Noise generation from a ball valve mainly induces by interference between unstable(or fluctuating) leakage flow and pipe wall when the ball valve is working closed or opened. To measure the positions of the noise source and the amplitude of noise with respect to measuring frequencies, a commercial acoustic camera is introduced. Noise characteristics generated by the ball valve have been performed by four valve opening rates: 30, 50, 70 and 100 percents. It is noted that 100 percent opening rate means that the valve is fully opened. Throughout the experimental measurements using the acoustic camera, the location of the noise source and the noise amplitude with respect to the frequencies for the test ball valve are clearly evaluated. It is found that the dominant frequencies come from the fluctuating flow at the downstream of the ball valve for four opening rates are observed between 3,000Hz and 3,200Hz. Maximum noise amplitude comes from the ball valve reaches 75dB at the valve opening rate of 50 percent.

• 한국정보통신학회논문지
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• 제20권4호
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• pp.755-762
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• 2016

모션그래픽이라는 분야는 그 역사가 오래되지 않았다. 최근 영상디자인이 부각되고 있는 것은 세계적인 추세이다. 이러한 세계적 흐름은 영화, 광고, 전시장 영상, 웹, 모바일, 게임영상 및 뉴미디어까지 그 영향을 미치고 있다. 또한 컴퓨터의 새로운 기술이 발달하면서 영상콘테츠의 VFX 분야가 급격하게 변화되고 있다. 이러한 제작기술은 실사와 C.G의 합성기법으로 가상과 허구의 개념을 초월함과 동시에 매치무빙 기술을 이용하여 그래픽과 현실공간에 사실적인 표현방법을 극대화하고 있다. 매치무빙 기술은 실사와 그래픽이 공존하기 위하서 실사카메라와 가상카메라의 합성을 정교하게 매칭하는 기술이다. 본 논문은 입체적 공간에서 매치무빙 기법을 활용하여 실사카메라의 움직임을 3D Layer 방법으로 이어받아 새로운 디자인과 결합된 모션그래픽 영상제작방법을 제안한다.

• International Journal of Quality Innovation
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• 제9권1호
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• pp.22-40
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• 2008

Unnatural working postures usually cause musculoskeletal problems for workers in work field, especially in traditional industry. Many analysis and survey methodologies have been developed to identify unnatural postures and disorder risks in workplaces. The Ovako Working Posture Analyzing System (OWAS) and Nordic Musculoskeletal Questionnaire (NMQ) are the representative methods and applied widely. This study applied the both tools to investigate the work field of a manufacturing factory of the water heater's case. We divided the manufacturing process into nine workshops, took the pictures of working motions by DV camera and analyzed the postures on OWAS. From the OW AS results, we could identify the risks level of musculoskeletal symptoms as four Action Categories (AC). And from the comparison of OWAS and NMQ results, we could provide the suggestions to improve the working methods and environment. From the results of OWAS, we found that the operators' head/neck and back were above AC3 in some workshops. If the situation continued in long period, the operators might have the risk to get musculoskeletal symptoms. From the investigation of NMQ, we also found that the percentage of aches on neck, shoulders and lower back were higher than other parts of body. The correlation between aches and jobs was more than 75%. So we provided some suggestions to improve: work rotation and adjustment of work surface/height to fit in with Ergonomics. Then the risks of musculoskeletal symptoms would be reduced.

• 만화애니메이션 연구
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• 통권32호
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• pp.263-288
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• 2013

본고는 영화에서 정평면적 앵글의 특성이 내포하는 효과에 관한 연구이다. 이러한 제한적 카메라 앵글은 수용자로 하여금 무언지 모를 긴장감을 갖게 하는데, 본고는 그 긴장감이 우연성에서 기인하고 있다고 본다. 본고는 하나의 서사물에서 그 우연성이 어떤 가치 면으로 어떻게 작용하여 어떤 효과를 갖는지에 대한 담론적 고찰이다. 러시아 형식주의자들은 내러티브를 완전히 배제함으로써 영화 자체의 미학적 가치에 접근하자는 주장을 해 왔는데, 이는 감각적인 각성이 지나친 감정이입을 막고 반성적 사유를 하게 한다는 브레히트의 소격화의 실천이라고 할 수 있다. 하지만 영화에서 시각적인 각성은 내용과의 관련에 따라서 때로는 반성적 사유보다는 더 깊은 관조로의 침잠을 유도하기도 한다. 본고는 정평면적 앵글이 쓰인 영화의 쇼트들 속에서 우연성의 가치를 조형적으로, 내용적으로 분석함으로써 이에 대한 사례를 찾아보고자 한다. 이를 위해 본고는 우연성에 대한 좀 더 세밀한 정의를 제시한다. 왜냐하면 회화, 사진 같은 정지영상에서 언급되어 왔던 우연성과 서사극에서 말하는 우연성이 성질을 달리 하기 때문이다. 그것은 형식상의 우연과 내용상의 우연으로 분류되어 고려되어질 것이다. 그리고 사실상 영화에서 '정평면적 앵글'의 조형적 범주가 무척 애매하므로 가능한 한 몇 개의 제한을 둠으로써 그 범주를 최대한 구체화시키고자 한다. 사례분석은 형식과 내용 면을 구분하여 담론적으로 서술하고자 한다. 결론적으로, 영화의 정평면적 앵글은 일차적으로 시각적 각성에 의한 주목성의 효과를 갖기는 한다. 하지만 감각적 각성이 항상 서사적 가치의 약화를 가져오는 것은 아니다. 전체 내용에 대한 사건의 인과성에 따라 정평면적 앵글이 갖는 우연성은 각성이 아닌 몰입의 가치에 봉사할 수도 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1953-1957
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• 2004

The machine vision has been applied to a number of industrial applications for quality control and automations to improve the manufacturing processes. In this paper, the automation system using the machine vision is developed, which is applicable to the marking process in a steel production process line. The working environment is very harsh to workers so that the automatic system in the steel industry is required increasingly. The developed automatic marking system consists of several mechanical and electrical elements such as the laser position detecting sensor system for a structured laser beam which is projected to the billet in order to detect the geometry of the billet. An image processing algorithm has been developed to percept the two center positions of a camera and a billet, respectively, and to align two centers. A series of experiments has been conducted to investigate the performance of the proposed algorithm. The results show that two centers of the camera and the billet could be detected very well and differences between two center positions could be also decreased via the proposed tracking algorithm.