CBCT를 이용한 3차원 안면비대칭분석

Yoon, Suk-Ja,Wang, Rui-Feng,Palomo, J. Martin 대한치과의사협회 2010 대한치과의사협회지 Vol.48 No.10

Accurate analysis of facial asymmetry prior to any orthognathic or orthodontic treatment plan is essential in ensuring good treatment result. Dental CBCT (Cone-beam Computed Tomography) provides as actual three-dimensional measurements of distance and angle without any radiographic magnification as medical CT provides, while its field of view is limited to the oral and maxillofacial area. CBCT is a useful tool for the diagnosis of facial asymmetry. The coordinates of facial landmarks are obtained from the 3D reconstruction software which enables the establishment of perpendicular planes and the identification of the landmarks. Then, the bilateral discrepancies of the landmarks are obtained as spherical polar coordinates which can show the amount of asymmetry and its direction. A method of 3D analysis of facial asymmetry using CBCT is introduced in this report.

파노라마방사선사진에서 석회화가 발견되는 경동맥의 협착 정도

조소양,오원만,윤숙자,윤웅,이재서,Juan M. Palomo,강병철 대한구강악안면방사선학회 2009 Imaging Science in Dentistry Vol.39 No.3

Purpose : This study aimed to investigate the luminal stenosis of the internal carotid artery with calcification detected on panoramic radiographs. Materials and Methods : This study used fifty carotid arteries of 36 dental patients whose panoramic radiograph and computed tomography angiography (CTA) revealed the presence of carotid artery calcification. A neuroradiologist interpreted CTA to determine the degree of stenosis of the internal carotid arteries. The degree of stenosis was stratified in four stages; normal (no stenosis), mild stenosis (1-49%), moderate stenosis (50-69%) and severe stenosis (70-99%). Results : Among the fifty carotid arteries with calcification detected on both panoramic radiography and CTA, 20 carotid arteries (40%) were normal, 29 carotid arteries (18%) had mild stenosis, 1 carotid artery (2%) had moderate stenosis, and there was none with severe stenosis. Conclusion : Sixty percent of the carotid arteries with calcification detected on both panoramic radiography and CTA had internal luminal stenosis, and two percent had moderate stenosis. When carotid atheroma is detected on panoramic radiograph, it is possible that the dental patient has luminal stenosis of the internal carotid artery. (Korean J Oral Maxillofac Radiol 2009; 39 : 157-61)

Averaged current mode control for maximum power point tracking in high-gain photovoltaic applications

Romo, David de la Rosa,Loera-Palomo, Rodrigo,Rivero, Michel,Sellschopp-Sanchez, Francisco S. The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.6

Efficient extraction of the maximum power from photovoltaic (PV) systems under inherently variable weather conditions is a key issue that has been tackled in recent years. Maximum power extraction techniques are relevant for increasing the penetration of PV systems into electric systems. This paper presents an averaged current mode control strategy as a maximum power extraction technique in a photovoltaic high step-up dc-dc converter, which can be applied to dc microgrids or ac networks through power inverters. Since the generated power of a photovoltaic system is related to the terminal voltage, power extraction is given through the regulation of the converter's input voltage. For this purpose, in the proposed averaged current mode control, the inner current loop uses the inductor current as a feedback signal, which improves the dynamic behavior of the converter with a simple gain. Meanwhile, the outer voltage loop is built with a proportional-integrative controller for regulation. The converter and control strategy are able to track rapid irradiance changes. They are also able to maintain the photovoltaic voltage regulation under dc bus voltage variations. The performance of the proposed control scheme is validated experimentally with a 100 W converter prototype.

중앙아메리카 북부삼각지대 이주, 폭력, 마약의 상관관계

림수진(SU JIN LIM),알렉산드로 팔로모 가리도(Aleksandro Palomo Garrido) 한국문화역사지리학회 2017 문화 역사 지리 Vol.29 No.2

이 논문은 중앙아메리카 북부삼각지대에 속하는 과테말라, 온두라스, 엘살바도르 3개 국에서 멕시코를 거쳐 미국에 이르는 이주자들에 관한 연구다. 최근 해당 국가들 뿐 아니라 세계 언론과 이주관련 기관이 우려를 표하는 이유는 이들이 멕시코를 관통하는 과정에서 직면하는 여정의 참혹함 때문이다. ‘죽음의 열차’라 불리는 화물열차의 지붕에 올라탄 채 미국에 이르기까지 짧게는 1000km, 길게는 3000km를 육로로 이동한다. 본 논문은 언급된 이주 현상의 요인을 분석한다. 본 논문의 구성은 다음과 같다. 첫째, 중아아메리카 북부 삼각지대에서 미국을 향해 가는 이주 증가 현상을 설명한다. 둘째, 배출요인으로 해당 각 국의 폭력 양상을 언급하고 기원을 분석한다. 셋째 해당 지역에 폭력이 극대화되는 요인으로 멕시코 마약 카르텔 조직과의 연계를 분석한다. 이를 통해 중앙아메리카 북부삼각지대 3개 국의 이주 현상이 폭력이라는 자국의 배출요인에서 기인하지만 그 이면에 마약과 관련한 각 국의 이해관계와 내전 시기 전후 미국 이민정책 변화가 배태되어 있음을 밝힌다. This article traces the migratory phenomena caused by the Central Americans. Most of them cross Mexican territory for the purpose to reach the United States of America. To get to the north, most of them hop on the top of a freight train known as “la bestia” or the beast and also known as “tren muerte” or the death train. This article focuses on the reasons for which Central Americans have chosen such a dangerous and abnormal migration these past years. This article consists of three parts. First, it explains the different characteristics that possess these migratory phenomena of the Central Americans who cross Mexico to get to the United States. Second, it analyzes the factors that cause the exodus of the Central American migrants focusing on ongoing violence and its origin. Third, it analyzes the reason of such severe violence in Central America’s Northern Triangle considering the relation between the local crime organizations and the Mexican drug cartels which have lowered the Central American countries due to the “war against drugs” in Mexico since 2006. In conclusion, this article detects the relation between migration, violence and drug in the Northern Triangle of Central America.

Deviation of landmarks in accordance with methods of establishing reference planes in three-dimensional facial CT evaluation

윤경원,윤숙자,강병철,김영희,국민석,이재서,Juan Martin Palomo 대한영상치의학회 2014 Imaging Science in Dentistry Vol.44 No.3

Purpose: This study aimed to investigate the deviation of landmarks from horizontal or midsagittal reference planes according to the methods of establishing reference planes. Materials and Methods: Computed tomography (CT) scans of 18 patients who received orthodontic and orthognathic surgical treatment were reviewed. Each CT scan was reconstructed by three methods for establishing three orthogonal reference planes (namely, the horizontal, midsagittal, and coronal reference planes). The horizontal (bilateral porions and bilateral orbitales) and midsagittal (crista galli, nasion, prechiasmatic point, opisthion, and anterior nasal spine) landmarks were identified on each CT scan. Vertical deviation of the horizontal landmarks and horizontal deviation of the midsagittal landmarks were measured. Results: The porion and orbitale, which were not involved in establishing the horizontal reference plane, were found to deviate vertically from the horizontal reference plane in the three methods. The midsagittal landmarks, which were not used for the midsagittal reference plane, deviated horizontally from the midsagittal reference plane in thethree methods. Conclusion: In a three-dimensional facial analysis, the vertical and horizontal deviations of the landmarks from the horizontal and midsagittal reference planes could vary depending on the methods of establishing reference planes.

Diagnostic methods for assessing maxillary skeletal and dental transverse deficiencies

Dena Sawchuk,Kris Currie,Manuel Lagravere Vich,Juan Martin Palomo,Carlos Flores-Mir 대한치과교정학회 2016 대한치과교정학회지 Vol.46 No.5

Objective: To evaluate the accuracy and reliability of the diagnostic tools available for assessing maxillary transverse deficiencies. Methods: An electronic search of three databases was performed from their date of establishment to April 2015, with manual searching of reference lists of relevant articles. Articles were considered for inclusion if they reported the accuracy or reliability of a diagnostic method or evaluation technique for maxillary transverse dimensions in mixed or permanent dentitions. Risk of bias was assessed in the included articles, using the Quality Assessment of Diagnostic Accuracy Studies tool-2. Results: Nine articles were selected. The studies were heterogeneous, with moderate to low methodological quality, and all had a high risk of bias. Four suggested that the use of arch width prediction indices with dental cast measurements is unreliable for use in diagnosis. Frontal cephalograms derived from cone-beam computed tomography (CBCT) images were reportedly more reliable for assessing intermaxillary transverse discrepancies than posteroanterior cephalograms. Two studies proposed new three-dimensional transverse analyses with CBCT images that were reportedly reliable, but have not been validated for clinical sensitivity or specificity. No studies reported sensitivity, specificity, positive or negative predictive values or likelihood ratios, or ROC curves of the methods for the diagnosis of transverse deficiencies. Conclusions: Current evidence does not enable solid conclusions to be drawn, owing to a lack of reliable high quality diagnostic studies evaluating maxillary transverse deficiencies. CBCT images are reportedly more reliable for diagnosis, but further validation is required to confirm CBCT’s accuracy and diagnostic superiority.

CBCT를 이용한 3차원 안면비대칭분석

윤숙자(Suk-Ja Yoon),Rui-Feng Wang,J. Martin Palomo 대한치과의사협회 2010 대한치과의사협회지 Vol.48 No.10

Accurate analysis of facial asymmetry prior to any orthognathic or orthodontic treatment plan is essential in ensuring good treatment result. Dental CBCT (Cone-beam Computed Tomography) provides as actual three-dimensional measurements of distance and angle without any radiographic magnification as medical CT provides, while its field of view is limited to the oral and maxillofacial area. CBCT is a useful tool for the diagnosis of facial asymmetry. The coordinates of facial landmarks are obtained from the 3D reconstruction software which enables the establishment of perpendicular planes and the identification of the landmarks. Then, the bilateral discrepancies of the landmarks are obtained as spherical polar coordinates which can show the amount of asymmetry and its direction. A method of 3D analysis of facial asymmetry using CBCT is introduced in this report.

Normal range of facial asymmetry in spherical coordinates : a CBCT study

Suk-Ja Yoon,Rui-Feng Wang,Hee Ja Na,Juan Martin Palomo 대한구강악안면방사선학회 2013 Imaging Science in Dentistry Vol.43 No.1

Purpose: This study aimed to measure the bilateral differences of facial lines in spherical coordinates from faces within a normal range of asymmetry utilizing cone-beam computed tomography (CBCT). Materials and Methods: CBCT scans from 22 females with normal symmetric-looking faces (mean age 24 years and 8 months) were selected for the study. The average menton deviation was 1.01±0.66 mm. The spherical coordinates, length, and midsagittal and coronal inclination angles of the ramal and mandibular lines were calculated from CBCT. The bilateral differences in the facial lines were determined. Results: All of the study subjects had minimal bilateral differences of facial lines. The normal range of facial asymmetry of the ramal and mandibular lines was obtained in spherical coordinates. Conclusion: The normal range of facial asymmetry in the spherical coordinate system in this study should be useful as a reference for diagnosing facial asymmetry.

Normal range of facial asymmetry in spherical coordinates: a CBCT study

Yoon, Suk-Ja,Wang, Rui-Feng,Na, Hee Ja,Palomo, Juan Martin Korean Academy of Oral and Maxillofacial Radiology 2013 Imaging Science in Dentistry Vol.43 No.1

Purpose: This study aimed to measure the bilateral differences of facial lines in spherical coordinates from faces within a normal range of asymmetry utilizing cone-beam computed tomography (CBCT). Materials and Methods: CBCT scans from 22 females with normal symmetric-looking faces (mean age 24 years and 8 months) were selected for the study. The average menton deviation was $1.01{\pm}0.66$ mm. The spherical coordinates, length, and midsagittal and coronal inclination angles of the ramal and mandibular lines were calculated from CBCT. The bilateral differences in the facial lines were determined. Results: All of the study subjects had minimal bilateral differences of facial lines. The normal range of facial asymmetry of the ramal and mandibular lines was obtained in spherical coordinates. Conclusion: The normal range of facial asymmetry in the spherical coordinate system in this study should be useful as a reference for diagnosing facial asymmetry.

Use of spherical coordinates to evaluate three-dimensional facial changes after orthognathic surgery

윤숙자,Rui-Feng Wang,유선열,황현식,강병철,이재서,Juan M. Palomo 대한영상치의학회 2014 Imaging Science in Dentistry Vol.44 No.1

Purpose: This study aimed to assess the three-dimensional (3D) facial changes after orthognathic surgery by evaluating the spherical coordinates of facial lines using 3D computed tomography (CT). Materials and Methods: A 19-year-old girl was diagnosed with class III malocclusion and facial asymmetry. Orthognathic surgery was performed after orthodontic treatment. Facial CT scans were taken before and after orthognathic surgery. The patient had a menton deviation of 12.72 mm before surgery and 0.83 mm after surgery. The spherical coordinates of four bilateral facial lines (ramal height, ramal lateral, ramal posterior and mandibular body) were estimated from CT scans before and after surgery on the deviated and opposite side. Results: The spherical coordinates of all facial lines changed after orthognathic surgery. Moreover, the bilateraldifferences of all facial lines changed after surgery, and no bilateral differences were zero. Conclusion: The spherical coordinate system was useful to compare differences between the presurgical and postsurgical changes to facial lines.