• Imaging Science in Dentistry
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• 제30권1호
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• pp.23-32
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• 2000

Purpose : The purpose of this study is to compare radiographic techniques for the diagnostic accuracy in the detection of osteophytes of the mandibular condyle. Material and Methods : A series of bone chips were placed at four locations on the condylar head of a dried human skull. Eight radiographic techniques such as panoramic, transcranial, infracranial, transorbital, reverse-Towne's, submentovertex, multidirectional tomographic and computed tomographic techniques were compared. Three oral radiologists were asked to rate the lesions by four stage score. The statistical analysis was performed by ANOVA test. Results: For the detection of lateral osteophyte, transcranial, infracranial, transorbital and reverse-Towne' s views showed superiority. Also, transcranial and infracranial views showed superiority for medial osteophyte. While for the detection of superior and anterior osteophyte, panoramic, transcranial, infracranial, transorbital views showed superiority. Lateral tomograph showed superiority for the detection of superior and anterior osteophyte, but it showed inferiority for lateral and medial osteophyte. And antero-posterior tomograph showed superiority for the detection of all osteophytes. Axial computed tomograph showed superiority for the detection of all osteophytes, and coronal computed tomograph showed superiority for lateral, medial and superior osteophytes. While reconstructed sagittal computed tomograph showed relatively superiority for the detection of anterior and superior osteophytes. Conclusion : The conventional radiographs can be used for the detection of bony changes of the mandibular condyle, and tomograph or computed tomograph can be used additionally when it is difficult to detect bony changes on conventional radiographs.

• 한국환경복원기술학회지
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• 제17권2호
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• pp.73-83
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• 2014

This study was conducted to evaluate defects in Zelkova serrata trees using an ultrasonic tomograph (PICUS) and suggest a management plan to maintain it as a natural and cultural resource. In previous study, health information of 16 protected trees were obtained by surveying the following categories; tree appearance, crown, bark, root exposure, water and nutrition, deterioration, pest, vitality, ground status, and pollutant. The average score of health was 16.5 in 16 trees, which means that general monitor is needed for management. In this study, the evaluation result of tree's inside defects using an ultrasonic tomograph showed that 43.8% of decay rate has been found in 16 trees. In fact, some trees look to be good even though they actually have a defects causing broken by natural disaster such as strong wind. Therefore, it is urgent to put some support to the trees and come up with a protective plan. The results of this study would be useful as basic data in developing a guideline for the efficient conservation and management of big and old trees.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2003년도 춘계학술발표회 논문집
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• pp.69-74
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• 2003

GPS/Meteorology technique for PWV monitoring is currently actively being researched an advanced nation. But, there is no detailed research on an evaluation of precision of GPS derived PWV measurements during the period of foul weather condition. Here, we deal with the precision of GPS derived PWV during the passage of Typhoon RUSA. Typhoon RUSA which caused a series damage was passed over in Korea from August 30 to September 1, 2002. We compared th tropospheric wet delay estimated from GPS observation and radio-sonde data at four sites(Suwon, Kwangju, Taegu, Cheju). The mean standard deviation of PWV differences at each site is ${\pm}$0.005mm. We also obtained GPS PWV at 13 GPS permanent stations(Seoul, Wonju, Seosan, Sangju, Junju, Cheongju, Taegu, Wuljin, Jinju, Daejeon, Mokpo, Sokcho, Jeju). GPS PWV time series shows, in general, peak value before and during th passage of RUSA, and low after the RUSA. GPS PWV peak time at each station is related to the progress of a typhoon RUSA. We obtained very similar result as we compare GMS satellite image with tomograph using GPS PWV and we could present th possibility of practical use by numerical model for weather forecast.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2005년도 춘계학술대회 논문집
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• pp.91-96
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• 2005

In this study, researchers developed the estimative algorithm for artificial defects in semiconductor packages and performed it by pattern recognition technology. For this purpose, the estimative algorithm was included that researchers made software with MATLAB. The software consists of some procedures including ultrasonic image acquisition, equalization filtering, Self-Organizing Map and Backpropagation Neural Network. Self-Organizing Map and Backpropagation Neural Network are belong to methods of Neural Networks. And the pattern recognition technology has applied to classify three kinds of detective patterns in semiconductor packages: Crack, Delamination and Normal. According to the results, we were confirmed that estimative algorithm was provided the recognition rates of $75.7\%$ (for Crack) and $83_4\%$ (for Delamination) and $87.2\%$ (for Normal).

• 한국측량학회지
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• 제21권1호
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• pp.9-17
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• 2003

한반도에 막대한 피해를 입힌 태풍 RUSA는 2002년 8월 30일에서 9월 1일간 한반도를 지나갔다. 이 태풍 RUSA가 진행하는 동안 GPS 수신 자료와 기상 자료를 이용하여 대류권에서의 습윤 지연량을 산출하고, 이 습윤지연량을 천정방향의 수증기량(IWV)으로 환산하여 이 수증기량으로부터 PWV(Precipitable Water Vapor)를 산출하였다. 본 연구에서는 서울, 원주, 서산, 상주, 전주, 청주, 대구, 울진, 진주, 대전, 목포, 속초, 제주의 13개 GPS 상시관측소 데이터를 이용하여 PWV를 산출하였다. 산출한 PWV의 시계열 분석을 통해 실제 강수량과 비교한 결과 태풍 RUSA가 진행하는 동안 PWV가 정점을 보이는 부근에서 실제 강수량이 발생하였다. 또한, 태풍 RUSA의 이동 경로와 PWV가 최고조를 이루는 시간을 분석한 결과 밀접한 관계가 있음을 알 수 있었다. GPS 자료로부터 산정된 PWV를 이용하여 tomograph를 작성하고 GMS 위성 영상과 비교한 결과 매우 근접한 결과를 얻을수 있었으므로 기상 예보를 위한 수치예보모델로의 활용 가능성을 제시할 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.697-698
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• 2012

• 한국생산제조학회지
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• 제23권1호
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• pp.27-31
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• 2014

This paper describes a tomographic imaging technique for evaluating the thickness reduction of a plate-like structure using a noncontact sensor network based on an electromagnetic acoustic transducer that generates shear horizontal plate waves. Because this technique is based on the effect of mode cutoff and time of flight of guided waves caused by a change in thickness, the tomographic image provides information on the presence of defects in the structure. To verify the performance of the method, artificial defects with various thickness reduction ratios were machined in an aluminum plate, and the tomographic imaging results are reported. The results show that the generated tomographic image displays the thickness reductions and can identify their locations. Therefore, the proposed technique has good potential as a tool for health monitoring of the integrity of plate-like structures.

• 치과방사선
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• 제24권2호
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• pp.227-236
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• 1994

The purpose of this study was to observe mandibular condyle shape in an asymptomatic population. In order to carry out this study, 96 temporomandibular joints in 48 adults(22 males, 26 females), who were asymptomatic for temporomandibular disturbances and had no history of prosthodontic or orthodontic treatments, were selected, and radiographed using the Sectograph(Denar Co., U.S.A.) for lateral and frontal individualized corrected TMJ tomograph and submentovertex radiograph. Mandibular condyles were classified morphologically, and measured medioateral and anteroposterior dimensions and condylar angulation. The obtained results were as follows. 1. In the classification of condyle shape on lateral tomographs, 94.8% were convex type and 5.2% were angled type. 2. In the classification of condyle shape on frontal tomographs, 45.3% were convex type, 32.0% were round type, 16.0% were flat type, and 6.7% were angled type. 3. In the classification of condyle shape on submentovertex radiographs, 34.5% were flat-convex type, 22.9% were flat-flat type, 20.8% were concave-convex type, 19.8% were convex-convex type, and 1.0% were concave-flat type and convex-flat type. Concave-concave type, convex-concave type, and flat-concave type were not observed. 4. The average mediolateral legth of the condyle was 19.3㎜ and the average anteroposterior length was 9.4㎜. The average angle between the long axis of condyle and the coronal plane made on submentovertex view was 19.6 degrees.

• Journal of Oral Medicine and Pain
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• 제37권2호
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• pp.125-133
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• 2012

측두하악관절 골관절염은 관절조직에 가해지는 과부하에 의해 관절면과 하부 골조직에서 일련의 퇴행성과정과 함께 관절부의 국소적 압통, 하악운동에 의한 관절의 염발음, 하악의 운동범위 제한, 심한 경우에는 과두지지가 없어져 구치부 과다접촉과 전치부 개교합이 나타날 수 있는 퇴행성질환이다. 일반적으로는 임상검사 후 파노라마방사선사진, 측두하악관절 파노라마, 경두개방사선사진을 촬영한 뒤 진단하게 되는데 이들 일반적인 방사선사진들은 질환 초기의 미세한 골변화를 평가하는데 제한적이다. 따라서 본 연구에서는 일반방사선학적 검사에서 골조직의 퇴행성변화가 의심되어 확진을 위해 단층촬영 및 골스캔 검사를 시행한 환자의 영상의학적 검사소견들 간의 일치도와 임상소견과의 관계를 평가하여 골관절염의 진단에서 이들 다양한 검사법들의 한계와 그 유용성을 평가하고 향후 추가연구를 위한 예비자료를 얻기위해 시행하였다. 골관절염의 진단에서 일반방사선사진과 단층촬영, 골스캔 검사의 결과 일치도가 비교적 높게 나타났지만 위음성 가능성이 존재하므로 임상검사소견에 따른 단계적인 영상의학적 검사 시행이 바람직할 것으로 사료된다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제31권6호
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• pp.492-498
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• 2009

We sought to evaluate the relationship between the mandibular canal and impacted mandibular third molars by using dental cone beam computed tomograph(CBCT) for third molar surgery. A total of 111 patients(177 teeth) offered the images through CBCT and panoramic radiography for the extraction of the mandibular third molars. In CBCT, the accurate relationship between the third molar and the mandibular canal were evaluated. In panoramic radiographies, we evaluated the impacted level and superimposition sign of the mandibular third molar with the mandibular canal, and also, the radiopacity of the white line in the canal. Data were statistically analyzed and estimated by $X^2$-test. In CBCT finding, high prevalence of contact between the mandibular canal and roots occured in the deep impacted third molars, narrowing mandibular canals, bending mandibular canals and cases where the radiopacity of white line of canals were "absence" on panoramic images. It showed statistical significance (P<0.05). When evaluating the mandibular canal and the roots through the panoramic radiography for third molar extraction, it could be difficult to diagnosis accurately. Thus, it is required to have an accurate diagnostic approach through CBCT that could evaluated the location between mandibular canal and root.