• 전기의세계
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• v.29 no.6
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• pp.349-353
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• 1980

본고에서는 기체중에서 전자의 전이과정을 관찰하기 위하여 많이 적용되어지는 방법에 대해서 기초적인 사항만 언급을 하였으나 이러한 technique를 사용함으로써 전하의 공간적인 분포상태를 파악할 수 있으며 avalanch의 전자나 이온의 이동으로 인하여 외부회로에 전류를 발생시키는데 이것은 amplifier와 oscilloscope에 의하여 측정을 할 수 있다. 또한 인가한 전계의 작용으로 전자가 양극으로 이동할 때 충돌전리작용에 의하여 새로운 전자를 생성할 뿐만 아니라 여기방사작용에 의하여 광자를 생성시킨다. 이러한 광자는 photomultiplier나 image-intensifier를 사용하므로써 감지할 수 있다. 이러한 결과로부터 우리는 전이현상의 기본적인 Data 즉 전자, 양이온 및 음이온의 이동속도, 전리계수 .alpha.와 부착계수 .eta.등을 유도할 수 있다.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.4
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• pp.471-480
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• 1999

This paper presents design and performance improvement of a new digital tomosynthesis (DTS) system for object-detector synchronous rotation. Firstly, a new DTS system, called OSDR (Object-Detector Synchronous Rotation) is suggested and designed to acquire X-ray digital images. Secondly, the shape distortion of DTS images generated by an image intensifier is modeled. And a new synthesis algorithm, which overcomes the limitations of the existing synthesis algorithm, is suggested to improve the sharpness of the synthesized image. Also an artifact analysis of the DTS system is performed. Thirdly, some performance indices, which evaluate quantitatively performance improvement, are defined. And the experimental verification of the performance improvement is accomplished by the ODSR system newly designed. The advantages of the ODSR system are expressed quantitatively, compared with an existing system.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.109-112
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• 1996

The more integrated and smaller SMD are needed, new solder joints packaging technologies are developed in these days such as BGA(Ball Grid Array), Flip Chip, J-lead etc. But, it's unable to inspect solder joints in those devices by visual inspection methods, because they are hided by it's packages. To inspect those new SMD packages, an X-ray system for acquiring a cross-sectional image of a arbitrary plane is necessary. In this paper, an analysis for designing X-ray cross sectional imaging system is presented including the way for correcting the distortion of image intensifier. And we show computer simulation of that system with a simple PCB model to show it's usefulness in applying PCB solder joint inspection.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.294-296
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• 1996

The process of detecting edge in an image is an important component of many Pattern Recognition and Computer Vision applications. In many practical cases, there exist blurred images due to defocussing, movement of an object and so on. In addition, local perturbation noise can be added to the images. We propose the edge detection technique in blurred and noisy image. For this, we use Fuzzy pyramid linking mothod to remove noise and enhance the edge in images. We develop contrast intensifier using the concept of Fuzzy sets as a postprocessing.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.29 no.2
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• pp.387-396
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• 1999

In dentistry. RadioVisioGraphy was introduced as a first electronic dental x-ray imaging modality in 1989. Thereafter. many types of direct digital radiographic system have been produced in the last decade. They are based either on charge-coupled device(CCD) or on storage phosphor technology. In addition. new types of digital radiographic system using amorphous selenium. image intensifier etc. are under development. Advantages of digital radiographic system are elimination of chemical processing, reduction in radiation dose. image processing, computer storage. electronic transfer of images and so on. Image processing includes image enhancement. image reconstruction. digital subtraction, etc. Especially digital subtraction and reconstruction can be applied in many aspects of clinical practice and research. Electronic transfer of images enables filmless dental hospital and teleradiology/teledentistry system. Since the first image management and communications system(IMACS) for dentomaxillofacial radiology was reported in 1992. IMACS in dental hospital has been increasing. Meanwhile. researches about computer-assisted diagnosis, such as structural analysis of bone trabecular patterns of mandible. feature extraction, automated identification of normal landmarks on cephalometric radiograph and automated image analysis for caries or periodontitis. have been performed actively in the last decade. Further developments in digital radiographic imaging modalities. image transmission system. imaging processing and automated analysis software will change the traditional clinical dental practice in the 21st century.

• Progress in Medical Physics
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• v.13 no.2
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• pp.90-97
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• 2002

The simulator which has a identical geometry with radiotherapy equipments, is a essential equipment to accomplish optimized radiotherapy plan through simulation by using diagnostic low energy X-ray. A Radiotherapy simulator has a combined technology from the therapeutic and diagnostic radiology and needs a periodical test for mechanical and optical properties, X-ray generator, image intensifier of simulator to keep the proper maintenance and radiation safety. Hence, tests were done and classified as i) mechanical and optical parameter for the gantry, collimator, and couch ii) key performance of the X-ray generator such as a kVp, mAs, and timer iii) performance of the image intensifier such as a resolution and contrast for three kinds of simulator, common use in clinic. The above result of tests will be applied to the acceptance test and periodical quality assurance procedure.

• Journal of the Korean Orthopaedic Association
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• v.55 no.3
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• pp.261-265
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• 2020

A lumbar juxtafacet cyst is a rare disease that causes low back pain, radiculopathy and neurological claudication by compressing the nerve roots. A 34-year-old male complained of severe low back pain and radicular pain in the right lower extremity. Magnetic resonance images revealed a cyst at the lateral recess of the spinal canal between the L3-4 disc and posterior facet joint that extended to the L4 body level. Under the guidance of an image intensifier, needle aspiration of the cyst was performed, which extracted 1.5 ml of serous, yellowish colored fluid. After the aspiration, the symptoms subsided dramatically. The follow-up magnetic resonance images showed no recurrence of the cyst. To the best of the author's knowledge, there are no reports of lumbar juxtafacet cyst treated with needle aspiration in Korea. This case is reported with a review of the relevant literature.

• Korean Journal of Optics and Photonics
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• v.9 no.4
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• pp.264-269
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• 1998

The Measurement of concentration patterns for $C_2$, CH and OH radicals in the premixed propane-air flame could be managed through an image processing technique. This technique was applied to the three kinds of flames on a bunsen burner-mixtures of fuel to be lean, optimum and excessive respectively. The image processing system was complished by treating single wavelength flame images around the eac radical luminescence band, which was obtained by using a set of narrow band pass filters, an image intensifier, CCD and PC. It was possible to observe and predict the reaction zone and the concentration distribution of the radicals, Spatial distribution of each radicals in the raaction zone gave us enough informations to analyze the reaction mechanisms in $C_mH_n$ combustion process. According to this informations, the image of $C_2$ radical exists at front zone, following the images of CH and OH radicals at downstream.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.3
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• pp.36-42
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• 2000

A fundamental experimental study for an alternative proposal to super-speed craft propulsion system called underwater ram-jet propulsion by high pressure air ejection as driving force was investigated. For basic study of the effects of ram-jet propulsion performance, a simple underwater ram-jet flow field was established and PIV(Particle Image Velocimetry) method was adopted to analyse the jet-induced flow appearing at ram intake, mixing chamber and nozzle. Some flow dynamics relating to the high-speed ram-jet effect were discussed for the basic understanding of the its propulsion principle.

• Journal of Welding and Joining
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• v.19 no.1
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• pp.88-94
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• 2001

DUPIC (Direct use of spent PWR fuel in CANDU reactors) nuclear fuel is a CANDU fuel fabricated remotely from spent PWR fuel materials in a hot cell. The soundness of the end closure welds of nuclear fuel elements is an important factor for the safety and performance of nuclear fuel. To evaluate the soundness of the end closure welds of DUPIC fuel element, a precise X-ray inspection system is developed using a micro-focus X-ray generator with an image intensifier and a real time camera system. The fuel elements made of Zircaloy-4 and stainless steel by an Nd:YAG laser welding and a TIG welding aye inspected by the developed inspection system. The soundness of the welds of the fuel elements was confirmed by the X-ray inspection process, and the irradiation test of DUPIC fuel elements has been successfully completed at the HANARO research reactor.