• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제34권6호
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• pp.622-627
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• 2008

In orthognathic surgery, precise analysis and diagnosis are essential for successful results. In facial asymmetric patient, traditional 2D image analysis has been used by lateral and P-A Cephalometric view, Skull PA, Panorama, Submentovertex view etc. But clinicians sometimes misdiagnose because they cannot find exact landmark due to superimposition, moreover image can be magnified and distorted by projection technique or patient's skull position, when using these analysis and method. For overcome these defects, analysis by using of 3D CT has been introduced. In this way we can analysis precisely by getting the exact image free of artifact and finding exact landmark with no interruption of superimposition. So we want to review of relationship between various skeletal landmarks of mandible or cranial base and facial asymmetry by predictable analysis using 3D CT. We select the cases of the patients who visited our department for correction of facial asymmetry during 2003-2007 and who were taken image of 3D CT for diagnosis. 3D CT images were reconstructed to 3D image by using V-Work program (Cybermed Inc., Seoul, Korea). And we analysis the relationship between facial asymmetry and various affecting factor of skeletal pattern. The mandibular ramus hight difference between right and left was most affecting factor that express facial asymmetry. And in this research, there was no relationship between cranial base and facial asymmetry. The angulation between facial midline and mandibular ramus divergency has significant relationship with facial asymmetry

• Maxillofacial Plastic and Reconstructive Surgery
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• 제31권3호
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• pp.229-236
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• 2009

Purpose: Some recent literatures report that it is possible to recover defected areas caused by enucleation of relatively large jaw cysts without using bone grafts. The aim was to find out whether spontaneous recovery of defected area with time occurred and what the contributing factors were. Materials and methods: In total, 194 patients were considered as patients. Out of these 194 patients, 74 patients who had no wound dehiscence and who were available for follow-up studies were selected. They were classified into two groups according to the size of radiolucent area in the preoperative panoramic radiographs: in one group, it was larger than $3{\times}4cm$, while in the other group, it was smaller than $3{\times}4cm$. Follow-up panoramic radiographs were taken immediately after the surgery, then after 3, 6, 9 and 12 months. On those radiographs, changes in size and density of the defected areas were observed using the Gray-level histogram of Adobe photoshop v7.0. Correlation between bone regeneration and factors such as the type and size of the cysts, age, sex, site of the cysts and systemic disease was evaluated using the General repeated measure and Mann-Whitney Test. Results: Analyses of panoramic radiographs showed that the recovery of radiopacity after 12 months was more than 97% on average in defected areas that were smaller than $3{\times}4cm$. in the defected areas that were larger than $3{\times}4cm$, considerable portion showed recovery of radiopacity. No statistically significant change was observed in bone density according to the type of cysts. Young patients under 20 years of age with highly active metabolism presented more significant bone regeneration than patients over 20 years of age. Bone regeneration was more hampered in patients who had medical disease, compared with patients who didn’t have any medical problem. No statistically significant change was seen in bone density according to sex. Changes in bone density according to the site of cysts such as maxilla, mandible, anterior or posterior region were not considered to be significant. Conclusion: Analyses of panoramic radiographs suggest that in approximately 12 months after the enucleation of cysts, clinically acceptable spontaneous bone regeneration can be observed even though normal bone graft procedures have not been applied.

• 방송공학회논문지
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• 제22권4호
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• pp.484-495
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• 2017

최근 디스플레이 기기의 발전과 기가 네트워크 등의 전송 대역폭 확대로 인해 대형 파노라마 영상, 4K Ultra High-Definition 방송, Ultra-Wide Viewing 영상 등 2K 이상의 초고해상도 영상의 수요가 폭발적으로 증가하고 있다. 이러한 초고해상도 영상은 데이터양이 매우 많기 때문에 부호화 효율이 가장 높은 High Efficiency Video Coding(HEVC) 비디오 부호화 표준을 사용하는 추세이다. HEVC는 가장 최신의 비디오 부호화 표준으로 다양한 부호화 툴을 이용하여 높은 부호화 효율을 제공하지만 복잡도 또한 이전 부호화 표준과 비교하여 매우 높다. 특히 초고해상도 영상을 HEVC 복호기로 실시간 복호화 하는 것은 매우 높은 복잡도를 요구한다. 따라서 본 논문에서는 고해상도 및 초고해상도 영상에 대한 HEVC 복호기의 복호화 속도를 개선시키고자 HEVC에서 지원하는 슬라이스(Slice)와 타일(Tile) 부호화 툴을 사용하여 각 슬라이스 혹은 타일을 동시에 처리하며 디블록킹 필터 과정에서도 소정의 블록 크기만큼 동시에 처리하는 데이터-레벨 병렬 처리 방법을 소개한다. 이는 독립 복호화가 가능한 타일, 슬라이스, 혹은 디블록킹 필터에서 동일 연산을 다중 스레드에 분배하는 방법으로 복호화 속도를 향상 시킬 수 있다. 실험에서 제안 방법이 HEVC 참조 소프트웨어 대비 4K 영상에 대해 최대 2.0배의 복호화 속도 개선을 얻을 수 있음을 보인다.

• 방송공학회논문지
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• 제23권4호
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• pp.559-573
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• 2018

최근 가상현실(VR, Virtual Reality) 등 가장 많은 분야에서 가장 활발히 응용되고 있는 영상매체 중 하나가 전방위 영상 또는 파노라마 영상이다. 이 영상은 다양한 방법으로 획득된 영상들을 스티칭하여 생성하는데, 그 과정에서 스티칭에 필요한 특징점들을 추출하는데 가장 많은 시간이 소요된다. 이에 본 논문은 현재 가장 널리 사용되고 있는 SIFT 특징점을 추출하는 연산시간을 감소하는 것에 목적을 두고 SIFT 특징점들을 추출에 관여하는 파라미터들을 분석한다. 본 논문에서 고려하는 파라미터는 가우시안 필터링에 사용되는 가우시안 커널의 초기 표준편차, 국소극점을 추출하기 위한 가우시안 차영상군의 수, 그리고 옥타브 수의 세 가지이다. SIFT 알고리즘으로는 이 알고리즘을 제안한 Lowe 방식과 컨볼루션 캐스캐이드(convolution cascade) 방식인 Hess 방식을 고려한다. 먼저 각 파라미터 값이 연산시간에 미치는 영향을 분석하고, 실제 스티칭 실험을 수행하여 각 파라미터가 스티칭 성능에 미치는 영향을 분석한다. 마지막으로 두 분석결과를 토대로 성능저하 없이 연산시간을 최소로 하는 파라미터 값들을 추출한다.

• 디자인학연구
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• 제18권4호
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• pp.215-224
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• 2005

최근 장식에 대한 관심이 증가하면서 제품의 외관을 다루는 작업의 중요성이 강조되고 있다 이는 색채 디자인 활동의 전문성으로 이어지고 있으며 이러 찬 상황에서 색채 디자인에 대한 개념의 재정립과 방향성의 제고는 불가피하다고 하겠다. 이와 같은 맥락에서 우리나라 색채 디자인의 출발점인 1960-70년대의 색채를 살펴봄으로써 색채 디자인의 적극적 도입 과정과 그 매커니즘에 대한 이해에 도움이 되고자 한다. 본 연구를 위해 60-70년대의 산업 재효의 색채에 관한 문헌을 조사 분석하여 색채의 특징을 구분하고 각각의 색채에 대한 배경과 의미를 고찰하였다. 연구 결과, 우리나라의 제품 색채는 산업화 속에서 제품의 기능적, 시각적인 마무리를 위한 개념에서 설정된 생산과 판매중심의 접근임을 알 수 있었다. 색채는 경제 성장을 향하는 물질가치 중심의 산업화의 이념과 제품에 대한 인식틀 속에서 그 방향성이 결정되었고 따라서 단순한 모방이나 기능적 보완, 또는 시각적인 주목성과 차별화기 기능 역할을 부여 받았다. 이러한 인식은 가전 제품을 중심으로 하는 백색, 소규모 일상용품을 중심으로 하는 순색, 가구와 같은 장식 개념의 제품을 중심으로 하는 자연 소재색의 3영역으로 나타났다. 이와 같은 연구는 제품 색채에 대한 연구가 미흡했던 점, 특히 제품 디자인에 대한 연구가 외형적 특성에만 집중하는 기존의 연구 태도로 인해 중요성의 인식이 부족하였던 색채에 대한 고찰이라는 면에서 의의를 갖는다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제23권2호
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• pp.107-114
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• 2001

Objectives : To compare jaw bone density of young adults (control group) and post-menopausal women(experimental group) in periapical and panoramic film. Materials and Methods : The bone mineral density values of lumbar and femur were measured by dual-energy X-ray absorptiometry(DEXA) and T scores of lumbar were obtained. T scores were classified into 3 group (T<-2.5, $-2.5{\leqq}T<-1$, $-1{\leqq}T$). Radiographic densities of alveolar bones were measured from interdental bones of premolar, molar areas in the maxilla and mandible and expressed into copper step wedge thickness by Scion $Image^{(R)}$ program. We considered these values of step wedge thickness as bone density of alveolar bone. Panorama mandibular index(PMI) was calculated by the method that the height of the inferior cortex of the mandible was divided by the height from the lower border of the mandible to the superior edge of the mental foramen. Bone density of alveolar bone and PMI were analysed statistically. Results : There were significant differences in bone mineral density of lumbar and femoral neck between control and experimental groups. There were also significant differences in bone density of premolar and molar area of jaw between control and experimental groups by MANOVA test. When considered lumbar T variables, there was only difference in interdental bone density of maxillary molar area between control and experimental group, but there was interaction. Interdental bone density of experimental group was appeared higher in $-1{\leqq}T$ group and lower in T<-2.5 group than control group. There was significant difference in PMI between control and experimental groups, but there was also inter action, thus, PMI of experimental group was appeared higher in $-1{\leqq}T$ group and lower in T<-2.5 group than control group. Conclusion : There were significant differences of alveolar density and cortical bone thickness between young men and post-menopausal women in periapical and panoramic film. These differences were dependent on lumbar T.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제27권2호
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• pp.167-173
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• 2001

Cystic lesion of the jaw are frequently encountered clinically. Although they rarely lead to development of tumors, they can result in resorption of the jaw bone or asymmetry of the face may occur. The purpose of this study is to find the clinical and histopathological pattern of cysts and to help better understanding for the diagnosis and treatment of jaw cysts. The hospital chart, out-patient chart, panorama X-ray, histopathological report and operation report of 246 patients were reviewed who had been diagnosed as cyst. Sex distribution, age distribution, classification, anatomic distribution, clinical sign & symptoms, treatment, post-operation complications, recurrence rate were studied. Then significant difference between the diameter of cyst with bone graft and none-bone graft was calculated with SAS program. The results were as follows. 1. Among the total patient of 246 cases, male were 163 case(67.0%), and female were 83 case(37.0%), male predominated by the ratio of 1.98. 2. By age group, the 20's accounted for the largest proportion of the cases(27.2%) and the 30' accounted for the 2nd largest proportion of the case(19.5%). 3. Radicular cyst and dentigerous cyst were most common cysts, irrespective of 166 case(67.5%) and 62 case(25.2%). 4. Clinical sign & symptoms were swelling(167case), pain(85case), pus discharge(53case), teeth discoloration(28case), indicating that most complaints were related to inflammation and facial asymmetry. 4.9% of the total cases were discovered accidentally. 5. The primary site of cysts were maxillary anterior area(43.9%), the others were, in descending order, mandibular posterior area(25.6%), maxillary posterior area(14.6%). 6. Enucleation with endodontic treatment was a main treatment method(133 case, 54.1%) and 38 cases(15.4%) were enucleation with extraction, and 37 cases(15.0%) were only enucleation, and 21 cases(8.5%) were enucleation with bone graft. 7. The average diameter of cysts with bone graft was significally greater than with non-bone graft(p<0.05). 8. Post-operation complications occurred in 10 case(4.1%), all of this were due to secondary infection.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제46권1호
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• pp.19-27
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• 2020

Objectives: Pentoxifylline (PTX) is a methylxanthine derivative that has been implicated in the pathogenesis of peripheral vessel disease and intermittent lameness. The purpose of this study was to investigate the effect of PTX and tocopherol in patients diagnosed with osteoradionecrosis (ORN), bisphosphonate-related osteonecrosis of the jaw (BRONJ), and chronic osteomyelitis using digital panoramic radiographs. Materials and Methods: This study was performed in 25 patients who were prescribed PTX and tocopherol for treatment of ORN, BRONJ, and chronic osteomyelitis between January 2014 and May 2018 in Seoul National University Dental Hospital. Radiographic densities of the dental panorama were compared prior to starting PTX and tocopherol, at 3 months, and at 6 months after prescription. Radiographic densities were measured using Adobe Photoshop CS6 (Adobe System Inc., USA). Blood sample tests showing the degree of inflammation at the initial visit were considered the baseline and compared with results after 3 to 6 months. Statistical analysis was performed using the Mann-Whitney test and repeated measurement ANOVA using IBM SPSS 23.0 (IBM Corp., USA). Results: Eight patients were diagnosed with ORN, nine patients with BRONJ, and the other 8 patients with chronic osteomyelitis. Ten of the 25 patients were men, average age was 66.32±14.39 years, and average duration of medication was 151.8±80.65 days (range, 56-315 days). Statistically significant increases were observed in the changes between 3 and 6 months after prescription (P<0.05). There was no significant difference between ORN, BRONJ, and chronic osteomyelitis. Only erythrocyte sedimentation rate (ESR) was statistically significantly lower than before treatment (P<0.05) among the white blood cell (WBC), ESR, and absolute neutrophil count (ANC). Conclusion: Long-term use of PTX and tocopherol can be an auxiliary method in the treatment of ORN, BRONJ, or chronic osteomyelitis in jaw.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2009년도 춘계 종합학술대회 논문집
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• pp.1118-1123
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• 2009

파노라마 촬영 시 눈과 갑상선의 표면선량 실험은 광주지역 10개 병원을 대상으로 열형광선량계(Thermoluminescent dosimeter, TLD)와 형광유리선량계(Photoluminescent dosimeter, PLD)를 이용하여 각각 병원에서 사용하는 조건으로 측정(measurement)하였다. ICRP 60과 ICRP 73에서 권고한 눈에 대한 허용기준은 15mSv, 갑상선에 대한 허용기준은 연간 1mSv이다. 왼쪽 눈(Left Eye)의 TLD와 PLD값은 각각 0.19mSv와 0.24mSv, 오른쪽 눈(Right Eye)의 TLD와 PLD의 값은 0.23mSv와 0.25mSv, 갑상선의 TLD와 PLD의 값은 0.08mSv와 0.25mSv로 허용기준치를 초과하지 않았다. 또한 각 장기에 대한 TLD와 PLD의 비교에서는 왼쪽 눈과 갑상선이 유의한 차이가 있다고 볼 수 있고(p<0.01), 오른쪽 눈은 유의한 차이가 없다고 볼 수 있다(p>0.05). 각 병원에서 사용하는 파노라마 기기로 눈과 갑상선에 미치는 선량을 TLD와 PLD로 측정 하였을 때 눈과 갑상선의 표면선량은 ICRP 60에서 권고한 선량을 넘지 않았지만, 확률적 영향이 일어날 수 있으므로 모든 준위의 선량에 대해서 고려되어야 한다.

• Imaging Science in Dentistry
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• 제40권1호
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• pp.39-44
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• 2010

Purpose : We want to identify the appearance of the buccolingual root dilaceration teeth in the panoramic views and specify the characteristics of these teeth. Materials and Methods : One thousand-six patients were examined on the basis of both panoramic and CT image criteria. We diagnosed and excluded certain teeth from the samples; both prosthodontic or pathologic lesion appearing teeth and mesiodistally dilacerated ones. We meticulously discerned buccolingually dilacerated teeth in the CT images and total 48 samples were selected. The degree of severity in dilaceration was standardized by 2 types of criteria. The samples were differentiated into 3 groups and again categorized into six types showing from the panoramic views: irregular view on the root apex area, clear blunt on the root tip, stepping on root tip, double lamina dura or double tip, arrow-target shaped root, bull's eye, normal view. Results : The types of teeth selected from total 48 buccolingual root dilaceration samples were mandibular first and second molar, premolars, canines, and lateral incisors. The direction of dilaceration was an even percentage to each buccal and lingual side for most selected teeth, however, that of both canines and lateral incisors were directed in almost a buccal side. In the panoramic views, the root types of the buccolingually dilacerated teeth were irregular view on the root apex area, clear blunt on the root tip, stepping on root tip and normal types were almost always normal view. The more severity in dilareated degree, the more chances of observation in the panoramic views were clear blunt on the root tip and stepping on root tip. Conclusion : As observed in the shape of stepping on root tip or double lamina dura in the panoramic views, there can be much more probability to diagnose as a buccolingually dilacerated root.