In-depth morphological study of mesiobuccal root canal systems in maxillary first molars: review

장석우,이종기,이윤,금기연 대한치과보존학회 2013 Restorative Dentistry & Endodontics Vol.38 No.1

A common failure in endodontic treatment of the permanent maxillary first molars is likely to be caused by an inability to locate, clean, and obturate the second mesiobuccal (MB) canals. Because of the importance of knowledge on these additional canals, there have been numerous studies which investigated the maxillary first molar MB root canal morphology using in vivo and laboratory methods. In this article, the protocols, advantages and disadvantages of various methodologies for in-depth study of maxillary first molar MB root canal morphology were discussed. Furthermore, newly identified configuration types for the establishment of new classification system were suggested based on two image reformatting techniques of micro-computed tomography, which can be useful as a further ‘Gold Standard’ method for in-depth morphological study of complex root canal systems. (Restor Dent Endod 2013;38(1):2-10)

자연의 초음파 소리와 알파파의 상관관계 연구

장석우,심한뫼,조옥희 사단법인 인문사회과학기술융합학회 2013 예술인문사회융합멀티미디어논문지 Vol.3 No.2

In this study, in order to study the effect of ultrasonic waves on human body, and see analyzes Examine ultrasound particular generated sound waves to promote the analysis of the electroencephalogram how they affected the brain is significant. The sound of the waves, that the most effective in order to be able to relax and degree of concentration as compared to the sounds of nature the other is known. It is utilized for the purpose of inducing relaxation of tension natural music with the help of this, the recorded sound waves to or utilize learning and rehabilitation and psychological therapy, with respect to the frequency delta waves it is classified as gamma waves (Gamma30 Hz or more) - (7 Hz Theta4), alpha wave (Alpha8-13 Hz), and beta waves (Beta14-30 Hz) (Delta1-3 Hz), sweater school. The present study, it was to be implemented separately only a specific frequency 40khz the effect of increasing the alpha waves emerging from the results of previous studies related appeared, the experiments were performed and produced by another device. 본 연구는 초음파가 인체에 미치는 영향을 연구하기 위해 뇌파 분석을 진행하여 파도소리에서 발생되는 특정 초음파가 두뇌에 어떤 영향을 미치는지 알아보고 분석해 보는데 의의가 있다. 파도소리는 다른 자연의 소리에 비해 집중도와 긴장이완을 하는 데 가장 효과적인 것으로 알려져 있다. 이를 활용하여 파도소리를 녹음한 자연음악들이 심리치료나 재활치료 또는 학습에 활용하기도 하며 긴장이완을 유도하는 용도로 활용되고 있는데 주파수에 따라 델타파(Delta 1-3 Hz), 세타파(Theta 4-7 Hz), 알파파(Alpha 8-13 Hz), 베타파(Beta 14-30 Hz) 및 감마파(Gamma 30 Hz 이상)로 분류된다. 이번 실험은 관련 선행 연구의 결과에서 나온 알파파의 증가의 효과가 나타난 40khz의 특정 주파수만 따로 구현하도록 하여 별도 기기로 제작하여 실험하였다.

17. 상추

장석우 한국원예학회 2013 한국원예학회 기타간행물 Vol.2013 No.5

Chemical characteristics of mineral trioxide aggregate and its hydration reaction

장석우 대한치과보존학회 2012 Restorative Dentistry & Endodontics Vol.37 No.4

Mineral trioxide aggregate (MTA) was developed in early 1990s and has been successfully used for root perforation repair, root end filling, and one-visit apexification. MTA is composed mainly of tricalcium silicate and dicalcium silicate. When MTA is hydrated, calcium silicate hydrate (CSH) and calcium hydroxide is formed. Formed calcium hydroxide interacts with the phosphate ion in body fluid and form amorphous calcium phosphate (ACP) which finally transforms into calcium deficient hydroxyapatite (CDHA). These mineral precipitate were reported to form the MTAdentin interfacial layer which enhances the sealing ability of MTA. Clinically, the use of zinc oxide euginol (ZOE) based materials may retard the setting of MTA. Also, the use of acids or contact with excessive blood should be avoided before complete set of MTA, because these conditions could adversely affect the hydration reaction of MTA. Further studies on the chemical nature of MTA hydration reaction are needed. Mineral trioxide aggregate (MTA) was developed in early 1990s and has been successfully used for root perforation repair, root end filling, and one-visit apexification. MTA is composed mainly of tricalcium silicate and dicalcium silicate. When MTA is hydrated, calcium silicate hydrate (CSH) and calcium hydroxide is formed. Formed calcium hydroxide interacts with the phosphate ion in body fluid and form amorphous calcium phosphate (ACP) which finally transforms into calcium deficient hydroxyapatite (CDHA). These mineral precipitate were reported to form the MTAdentin interfacial layer which enhances the sealing ability of MTA. Clinically, the use of zinc oxide euginol (ZOE) based materials may retard the setting of MTA. Also, the use of acids or contact with excessive blood should be avoided before complete set of MTA, because these conditions could adversely affect the hydration reaction of MTA. Further studies on the chemical nature of MTA hydration reaction are needed.

컬러 영상에서 추적 기능을 활용한 얼굴 영역 검출 및 차단

장석우 한국산학기술학회 2020 한국산학기술학회논문지 Vol.21 No.10

In recent years, the rapid increases in video distribution and viewing over the Internet have increased the risk of personal information exposure. In this paper, a method is proposed to robustly identify areas in images where a person's privacy is compromised and simultaneously blocking the object area by blurring it while rapidly tracking it using a prediction algorithm. With this method, the target object area is accurately identified using artificial neural network-based learning. The detected object area is then tracked using a location prediction algorithm and is continuously blocked by blurring it. Experimental results show that the proposed method effectively blocks private areas in images by blurring them, while at the same time tracking the target objects about 2.5% more accurately than another existing method. The proposed blocking method is expected to be useful in many applications, such as protection of personal information, video security, object tracking, etc. 최근 들어, 동영상의 간편한 촬영 그리고 인터넷을 통한 동영상의 보급 및 시청이 기하급수적으로 늘어남에 따라서 개인 정보의 외부 노출로 인한 피해가 발생하고 있다. 본 논문에서는 연속적으로 들어오는 영상으로부터 사람의 개인 정보가 노출된 목표 객체 영역을 강인하게 추출한 다음, 추출된 객체를 위치 예측 알고리즘을 이용해 빠르게 추적하면서 영상 블러링 기법을 통해 동시에 블로킹하는 새로운 방법을 제안한다. 본 논문에서는 먼저 입력받은 컬러 영상으로부터 개인 정보 영역이 노출된 목표 객체 영역을 인공 신경망 기반의 학습 알고리즘을 이용하여 정확하게 추출한다. 그런 다음, 검출된 객체를 위치 예측 알고리즘을 이용하여 빠르게 추적하면서 영상 블러링을 적용하여 블로킹한다. 실험 결과에서는 제안된 방법이 받아들인 다양한 종류의 컬러 영상 데이터로부터 개인 정보가 노출된 목표 객체를 기존 방법에 비해 2.5% 보다 정확하게 추적하면서 동시에 블러링함으로써 개인 정보 영역을 효과적으로 차단한다는 것을 보여준다. 본 논문에서 제안된 물체 차단 방법은 개인 정보의 보호, 비디오 감시 및 보안, 객체 검출 및 추적 등과 같은 많은 실제적인 응용 분야에서 유용하게 활용될 수 있을 것으로 기대된다.

FRACTURE RESISTANCE OF CROWN-ROOT FRACTURED TEETH REPAIRED WITH DUAL-CURED COMPOSITE RESIN AND HORIZONTAL POSTS

장석우,이용근,경승현,유현미,오태석,박동성,Chang, Seok-Woo,Lee, Yong-Keun,Kyung, Seung-Hyun,Yoo, Hyun-Mi,Oh, Tae-Seok,Park, Dong-Sung The Korean Academy of Conservative Dentistry 2009 Restorative Dentistry & Endodontics Vol.34 No.5

The purpose of this study was to investigate the fracture resistance of crown-root fractured teeth repaired with dual-cured composite resin and horizontal posts. 48 extracted human premolars were assigned to control group and three experimental groups. Complete crown-root fractures were experimentally induced in all control and experimental teeth. In the control group. the teeth (n=12) were bonded with resin cement and endodontically treated. Thereafter, the access cavities were sealed with dual-cured composite resin. In composite resin core-post group (n=12), the teeth were endodontically treated and access cavities were sealed with dual-cured composite resin. In addition, the fractured segments in this group were fixed using horizontal posts. In composite resin core group (n=12), the teeth were endodontically treated and the access cavities were filled with dual-cured composite resin without horizontal posts. In bonded amalgam group (n = 12), the teeth were endodontically treated and the access cavities were sealed with bonded amalgam. Experimental complete crown-root fractures were induced again on repaired control and experimental teeth. The ratio of fracture resistance to original fracture resistance was analyzed with Kruskal-Wallis test. The results showed that teeth in control and composite resin core-post group showed significantly higher resistance to re-fracture than those in amalgam core group (p < 0.05). The resistance to refracture was high in the order of composite resin - post group, control group, composite resin group and bonded amalgam group. Within the scope of this study, the use of horizontal post could be beneficial in increasing the fracture resistance of previously fractured teeth. 이 연구의 목적은 이중 중합복합레진과 수평 포스트를 이용하여 수복한 치관-치근 복합파절 치아의 수직파절 저항성을 알아보기 위한 것이다. 48개의 발치된 사람의 소구치에 실험적으로 치관-치근 복합파절을 일으킨 후 대조군 및 3개의 실험군에 (n=12) 각각 할당하였다. 대조군에서는 치아 파절편을 레진시멘트를 이용하여 접착한 후 근관치료를 시행하고, 근관와동을 이중중합 복합레진을 사용하여 충전하였다. 실험군에서는, 각각의 치아에 근관치료를 시행한 후 레진-포스트 군에서는 근관와동을 수평 포스트 및 이중중합 복합레진을사용하여 충전하였다. 레진 군에서는 근관와동을 포스트 없이 이중중합 복합레진만 사용하여 수복하였으며 아말감 코어 군에서는 근관와동을 접착 아말감을 사용하여 수복하였다. 이렇게 수복된 치아를 처음과 같은 방법으로 다시 치관-치근 복합파절을 유도하여 이때의 파절 저항성을 기록하고 이 값과 처음 파절을 유도하였을 때의 파절 저항성의 비를 계산하고 각 군별로 차이가 있는 지 검증하기 위해 Kruskal-Wallis test를 시행하였다. 수복된 치아의 파절저항성은 레진-포스트군, 대조군, 레진군, 접착 아말감 순으로 높았으며, 이 실험결과로 볼 때,치관-치근 복합파절 치아의 수복 시 수평 포스트를 사용하는 것이 재파절 방지를 위해 효과적 일 것으로 사료된다.

농업기술 - 봄철 상추재배 품종과 재배기술

장석우,Jang, Seok-U 전국농업기술자협회 2011 농업기술회보 Vol.48 No.3

웰빙 (well-being)시대의 대표적인 채소인 상추는 쌈뿐만 아니라 연하고, 아삭아삭한 독특한 맛 때문에 샐러드로 많이 이용된다. 수분 함량은 95% 정도며 비타민 A, B, C, E 및 다량의 철분을 함유하고 있어 영양가가 매우 풍부하여 생식용으로 적합하다. 또한 상추는 봄, 가을재배가 가장 적합한 작물로 특히 봄 재배는 일조량이 많고 주야간의 온도차가 커서 상추재배에 가장 알맞을 뿐만 아니라 맛 또한 일품이다.

Measurement of Contact Angle and Bond Strength Using 3 Different Self-Etching Primer

장석우,권호범,유현미,박동성,오태석,배광식 대한턱관절교합학회 2008 구강회복응용과학지 Vol.24 No.1

The purpose of this study was to evaluate the contact angle made by 3 kinds of self etching primers (Clearfil SE Bond, AdheSE, and Tyrian) on dentin and to measure the microtensile bond strength of resin composite to dentin using these self-etching primers. Contact angle between each of 3 self etching primers and polished dentin surface was measured (n=30) by contact angle analyzer and the result was analyzed by One-way ANOVA. For the measurement of microtensile bond strength, polished dentin surface was treated with each of 3 self etching primers and dentin adhesives. Z-250 composite resin was built-up with a height of 5 mm on the adhesive-treated surface and light cured for 40s with a halogen light curing unit. Thereafter, each tooth was sectioned into slabs perpendicular to the bonded interface and trimmed (n=45). The microtensile bond strength was measured with universal testing machine and the result was analyzed with Kruskal-Wallis test. AdheSE group showed the highest contact angle followed by Clearfil SE group and Tyrian group (p<0.05). AdheSE group and Clearfil SE group showed significantly higher microtensile bond strength than Tyrian group (P<0.05).

노동조합과 쟁의행위, 집회시위에 대한 공권력 행사의 한계

장석우 민주사회를 위한 변호사모임 2022 노동판례비평 Vol.27 No.-

최근 통상임금 소송에서 신의칙 판단의 경향과 비판

장석우 민주사회를 위한 변호사모임 2021 노동판례비평 Vol.26 No.-