• The korean journal of orthodontics
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• v.32 no.6 s.95
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• pp.425-434
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• 2002

The purpose of this investigation was to study the spatial changes of the maxillofacial complex following maxillary protraction transmitted to the center of resistance of a dry juvenile human skull by a modified maxillary protraction appliance. Four dry juvenile human skulls (without mandible) with well aligned upper deciduous dentition and early mixed dentition were used as experimental samples. A modified protraction headgear was fabricated from a Delare's facemask, and following an alginate impression, an orthodontic resin maxillary splint was made for each dry skull. Protraction force level was maintained at approximately 1000gm per side for 6 hours. Cephalometric radiographs were taken pre- and post- protraction, and nine reference markers with 1.5 mm length of $.017\times.025$ TMA wire were placed on the right side of the skull for an accurate superimposition of serial cephalometric radiographs. The present investigation demonstrated that vertical changes associated with an anterior displacement of the maxillary complex was observed, and the most prominent effect of protraction headgear was a counterclockwise rotation of the maxilla, that is, a forward and downward tipping around the palatomaxillary region.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.104-112
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• 2012

Recently, the HDR imaging technique that mimics human eye is incorporated with LCD/LED display devices to deal with mismatch between the real world scene and the displayed image. However, HDR image has a veiling glare limit as well as a scale of the local contrast problem. In order to overcome these problems, several color correction methods, CSR(center/surround Retinex), MSR (Multi-Scale Retinex), tone-mapping method, iCAM06 and so on, are proposed. However, these methods have a dominated color throughout the entire resulting image after performing color correction. Accordingly, this paper presents a new color correction method using dynamic cone response function. The proposed color correction method consists of tone-mapping and dynamic cone response. The tone-mapping is obtained by using a linear interpolation between chromatic and achromatic. Thereafter, the resulting image is processed through the dynamic cone response function, which estimates the dynamic responses of human visual system as well as deals with mismatch between the real scene image and the rendered image. The experiment results show that the proposed method yields better performance of color correction over the conventional methods.

• Journal of the Korean Society of Radiology
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• v.10 no.6
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• pp.457-468
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• 2016

The purpose of this study was to investigate factors of perception by inpatients of the Medical Examination institutions about exposure to radioactivity at the time of radioactive examination, providing basic information for making educational materials aimed to change their perception. Most of those patients, 72.0% responded that CT was a type of radioactive examination bringing highest exposure to radiosensitivity. Most of the subjects, 63.5% said that a body part most vulnerable to exposure to radiosensitivity was the genital gland at the time of radiosensitivity examination. And most of the participants, or 29.0% responded that they obtained information about radiation from TVs or newspapers. Among the surveyed patients, men were higher in scores for factors of the perception of radiation such as recognition of radiation, harmfulness of radiation, psychological state at the time of radioactive examination, prevention of exposure to radioactivity and necessity of radiation that women were, with statistically significant differences between the two groups. These findings suggest that it is urgently needed to develop an education program which helps patients better perceive exposure to radioactivity and that radiologists should be very careful to reduce the does of that exposure. If patients better perceive radiation, they would be less anxious and less exposed to radioactivity when receiving the radioactive examination.

• Radiation Oncology Journal
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• v.10 no.1
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• pp.101-105
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• 1992

Authors performed a stereotactic radiosurgery with multiple noncoplanar convergent photon beams of linear accelerator (NELAC-1018 18 MeV, NEC) using a specially designed Yeungnam localization device for two patients with recurrent glioblastoma multiforme. One patient had 2 cm sized and the other 4 cm sized mass on the CT images. After single session of treatment with 15 and 20 Gy, headache was improved in a few days after radiosurgery with no remarkable untoward reactions. Our experience with these two patients were encouraging and we found that our localization device, which is easily adjustable and inexpensive, could be a valuable tool for stereotactic radiosurgery particularly in the treatment of recurrent brain tumor.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1415-1419
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• 2006

메탄을 탄소원 및 에너지원으로 이용하는 메탄산화균은 물질대사과정 중에 다량의 세포외 고분자물질인 Extracellular polymeric substances(EPS)를 생성하는데, EPS는 카르복실기와 같은 표면흡착 기능을 가지고 있어 생체흡착제로 사용이 가능하다. 따라서 본 연구에서는 메탄산화세균을 이용하여 중금속인 Cd의 흡착성능을 파악하여 활성슬러지의 흡착능과 비교하고, EPS 농도별, pH별 흡착량의 변화를 실험한 후 Freundlich 흡착모델식에 적용하여 흡착공정의 기본적인 설계인자를 도출하고자 하였다. 실험에 사용한 메탄산화세균은 매립지 복토층 상부 토양에서 분리하여 실험실에서 대량으로 배양하였으며, EPS 생성을 위해 메탄을 Head space의 20%를 주입하고 $30^{\circ}C$, 150rpm에서 질소원이 부족한 조건으로 48hr 동안 배양하였다. Cd의 흡착실험은 용액의 pH를 3에서 8까지 변화를 주면서 활성슬러지와 메탄산화세균의 시간별 흡착능을 측정하였다. 또한 중금속의 농도별 흡착능을 측정하여 흡착평형 상수를 파악하였으며, 중금속 흡착 전, 후 미생물의 SEM 촬영, FT-IR 분석, 전자현미분석(EPMA)을 통하여 무기성분 분석 및 표면관찰을 수행하였다. 실험결과 메탄산화세균에 의해 생성된 EPS 물질은 중금속에 대한 강한 결합능력이 있으며, Cd에 대한 최고 흡착능은 26mg Cd(Ⅱ)/g VSS의 값을 보였다. 이러한 미생물의 EPS의 흡착능은 pH와 칼슘이온의 영향을 많이 받았으며, 메탄산화세균의 FT-IR 분석결과 EPS에는 sulfate ester, pyruvate 등과 같은 작용기와 amino sugar, carboxyl 작용기들이 많이 존재하여 활성슬러지에 비해 중금속의 흡착능이 높은 것으로 사료되었다.X>${\mu}_{max,A}$는 최대암모니아 섭취률을 이용하여 구한 결과 $0.65d^{-1}$로 나타났다.EX>$60%{\sim}87%$가 수심 10m 이내에 분포하였고, 녹조강과 남조강이 우점하는 하절기에는 5m 이내에 주로 분포하였다. 취수탑 지점의 수심이 연중 $25{\sim}35m$를 유지하는 H호의 경우 간헐식 폭기장치를 가동하는 기간은 물론 그 외 기간에도 취수구의 심도를 표층 10m 이하로 유지 할 경우 전체 조류 유입량을 60% 이상 저감할 수 있을 것으로 조사되었다.심볼 및 색채 디자인 등의 작업이 수반되어야 하며, 이들을 고려한 인터넷용 GIS기본도를 신규 제작한다. 상습침수지구와 관련된 각종 GIS데이타와 각 기관이 보유하고 있는 공공정보 가운데 공간정보와 연계되어야 하는 자료를 인터넷 GIS를 이용하여 효율적으로 관리하기 위해서는 단계별 구축전략이 필요하다. 따라서 본 논문에서는 인터넷 GIS를 이용하여 상습침수구역관련 정보를 검색, 처리 및 분석할 수 있는 상습침수 구역 종합정보화 시스템을 구축토록 하였다.N, 항목에서 보 상류가 높게 나타났으나, 철거되지 않은 검전보나 안양대교보에 비해 그 차이가 크지 않은 것으로 나타났다.의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행태적 측면과 투자성과측면의 실증결과를 통하여 한국주식시장에 있어서 시장수익률을 평균적으로 초과할 수 있는 거래전

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1341-1349
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• 2011

This research is focused on an analysis on the structure of RAW image file and the development of a RAW image file viewer for an embedded device. Recently, several RAW image file formats are being used for saving and displaying the images created by various DSLR cameras, and the necessity of handing RAW images in mobile multimedia devices is increasing. For the development of RAW image decoding/encoding library applicable to WinCE-based embedded devices viewer, an analysis of RAW image file formats, such as CRW, CR2, PEF, NEF, MRW, have been performed because their formats are not released in public. By using the library, the analysis software which can extract RAW image data, 2~3 JPEG image files and other informations such as the specification of a camera and various photographic parameters from RAW image files, were developped and a RAW image file viewer which can run in WinCE-based embedded devices. The experimental result has shown that the viewer could encode and decode RAW image files successfully and it took approximately 10secs to load them to the screen in S3C6410 based embedded platform. The outcomes of this research cloud be a good information and solution to multimedia application developers.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.96-99
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• 2004

The objective of this study is to assess attenuation correction algorithms utilized in a multipurpose whole-body GSO PET scanner. Four different types of phantoms were tested using different types of attenuation correction techniques. FOV (Field of View) of 256mm was used for brain PET imaging. For compensating attenuation, transmission data of a $^{137}$Cs point source were acquired after the F-18 emission source was infused to the phantoms. Scatter correction were peformed. Reconstructed images of the phantoms were assessed. In addition, reconstructed images of a normal subject were compared and assessed by nuclear medicine physicians. As a result, decreased intensity at the central portion of the attenuation map with cylindrical phantom was noticed during use of the measured attenuation correction. On the other hand, segmentation or remapping attenuation correction provided uniform phantom image. the images reconstructed from the clinical brain data explained the attenuation of a skull, at though reconstructed images of the phantoms couldn't explain it. in conclusion, the complicated and improved attenuation correction methods were required to obtain the better accuracy of the quantitative brain PET images. Our study will be useful in improving quantitative brain PET imaging modalities with attenuation correction of $^{137}$Cs transmission source.

• Journal of the Korean Society of Radiology
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• v.7 no.5
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• pp.365-369
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• 2013

Intravenous injection is administered with radioactive medical isotopes to detect disease on Positron Emission Tomography (PET). In this case, typically, $^{18}FDG$ (Fluorodeoxyglucose) is used as a radioactive medicine. Cassette equipment is needed to synthesize deoxyglucose with $^{18}F$, produced by medical cyclotron. Production of radioactive medicine creates a lot of radiation, thus Hot Cell is used to shield a secondary radiation. We measured the radiation dosage flowing out of the hot cell during synthesis of $^{18}FDG$ or distribution. The purpose of this study is to provide the information of radiation dosage regarding the occupational exposure that unintentionally occurs during the synthesis of $^{18}FDG$. In conclusion, we confirmed the radiation dosage out of the hot cell during the $^{18}FDG$ synthesis. Especially, we observed that the radiation flowed out through the lead window, attached as a view port. Thus, it is considered that the improvement of a lead window is necessary in order to decrease the occupational exposure during the $^{18}FDG$ synthesis.

• Journal of the Korean Society of Radiology
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• v.7 no.2
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• pp.131-136
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• 2013

Panorama of dental radiation generators can observe the wide anatomical structures of oral and maxillofacial areas but there can be distortion of lengths, angles, or shapes. CBCT can diagnose 3D images and get the ones whose errors by superposition and interference are remarkably smaller between anatomical structures. But the quality of the images by movement of subjects can be lowered as it takes long to diagnose them. And if there are impermeable radiation objects like metal in mouths, impermeable radiation lines can radially appear with the objects as center. This study tries to analyze accuracy of panorama and CBCT and get useful anatomical information in dental treatment by comparing the length of wisdom teeth which were measured by Panorama and CBCT with the teeth which were actually extracted and analyzing distortion of the teeth. The test result could be found that Panorama is expanded by average 7.3% as the errors of Panorama and Digital Vernier Caliper range from 110.7% to 103.9%. The length of wisdom teeth which were measured in CBCT and Digital Vernier Caliper could be found that the error range is 1.3%. And the length of wisdom teeth which were measured in Panorama and Digital Vernier Caliper has found that the error range shows 7.3%. So it could be found that the images of CBCT is about 6% more exact than those of Panorama. It could be found that CBCT shows the more exact images than those of Panorama. But because the examination expenses of CBCT are higher than those of Panorama and exposure dose of CBCT is much more than that of Panorama, it is thought to find proper ways in examination.

• Journal of the Korean Society of Radiology
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• v.7 no.5
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• pp.321-331
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• 2013

The purpose of this study was to investigate factors of perception by inpatients of the radiology department about exposure to radioactivity at the time of radioactive examination, providing basic information for making educational materials aimed to change their perception. Most of those patients, 65.5% responded that CT was a type of radioactive examination bringing highest exposure to radiosensitivity. Most of the subjects, 56.1% said that a body part most vulnerable to exposure to radiosensitivity was the genital gland at the time of radiosensitivity examination. And most of the participants, or 26.3% responded that they obtained information about radiation from TVs or newspapers. Among the surveyed patients, men were higher in scores for factors of the perception of radiation such as recognition of radiation, harmfulness of radiation, psychological state at the time of radioactive examination, prevention of exposure to radioactivity and necessity of radiation that women were, with statistically significant differences between the two groups. These findings suggest that it is urgently needed to develop an education program which helps patients better perceive exposure to radioactivity and that radiologists should be very careful to reduce the does of that exposure. If patients better perceive radiation, they would be less anxious and less exposed to radioactivity when receiving the radioactive examination.