율-왜곡 이론에 의한 H.263부호기의 성능 분석

황재정,황치규,박종필 群山大學校 情報通信技術硏究所 1998 情報通信技術硏究論文集 Vol.2 No.-

Rate-distortion theory means that the lower limit of transmission rate is determind according to the distortion quantity. This theory is fundamentally important factor in the visual system without visually sensitive distortion. Rate-distortion theory originating in the notion of information quantity is derived using probability distribution of orignal signal and measurement of distortion. In this paper, we develop the R(D) function with the distribution function of Gaussian and Laplacian, using the absolute error criteria and the square error criteria. Then we applied these functions to H.263 video coder at very low-bitrate. Though the Laplacian and Gaussian distribution can be applied, we show that the lowest point on which the rate becomes zero is lower in the case of Laplacian than in the case of Gaussian.

2종 전자근관장측정기의 일관성에 관한 in vitro 연구

황규용,노병덕,김의성,이승종 大韓齒科保存學會 2008 Restorative Dentistry & Endodontics Vol.33 No.1

정확한 근관장 측정은 성공적인 근관치료를 위해 필수적이다. Kuttler는 근관협착부는 주근단공에서 0.5 mm 상방에 위치한다고 하였고 Lee는 상아백악질경계점부위보다 주근단공이 재현성이 높고 임상적으로 관찰하기 용이하다고 보고하였다. 본 연구는 alginate model상에서 2개의 전자근관장측정기를 사용하여 얻은 측정치의 정확성(accuracy)을 평가하고 각각 0.5 mark와 Apex mark중에서 어느 지점에서 더 일관성(consistency)을 보이는지를 비교하고 또한 근관장을 측정할 때 파일을 전진시키면서 Apex mark를 측정한 값과 치근단부위를 지나친 후 다시 후퇴하면서 측정한 값의 차이를 비교하고자 하였다. 52개의 발거된 건전한 제 1, 2소구치를 대상으로 하였으며 Root ZX와 E-Magic Finder Deluxe를 이용하여 각각 26개중 13개는 파일을 전진하면서 0.5 mark에서 근관장을 측정하고 Apex mark에서 근관장을 측정한 후 0.5 mark에서 고정하였다. 나머지 13개는 0.5 mark에서 근관장을 측정한 후 Apex mark에서 근관장을 측정하고 다시 치근단 부위를 넘어선 후 후퇴하면서 Apex mark에서 근관장을 측정하고 고정한 후 치근단부 4 mm를 삭제하여 현미경상에서 파일 끝부터 주근단공까지의 거리를 측정하였다. 그 결과 Root ZX와 E-Magic Finder 모두, 실험군 100%에서 주근단공과 file tip간의 거리가 임상적 허용범위인 ± 0.5 mm 내에 있었으며 0.5 mark보다 Apex mark에서 더 높은 일관성을 보였다. 주근단공에서 file tip 사이의 거리는 Root ZX의 0.5 mark에서 -0.18 mm, Apex mark에서 -0.07 mm 이고 E-Magic Finder의 0.5 mark에서 -0.25 mm, Apex mark에서 -0.02 mm를 나타내었다. Apex band는 0.04 mm였다. 따라서 Alginate model을 사용한 본 실험조건에서는 Apex mark에서 근관장을 측정한 결과 거의 주근단공과 일치하고 다른 여러 연구에서 주근단공에서 0.5 mm 상방에 근관협착부가 위치한다고 보고하였으므로 임상적인 측면에서 Apex mark에서 측정한 근관장에서 0.5 mm 를 빼서 근관장으로 사용하는 것이 임상적으로 더 좋으리라고 사료된다. The purpose of this study was to evaluate the consistency of two electronic apex locators in vitro model. Materials consisted of fifty two extracted premolars and two electronic apex locators: Root ZX (J.Morita. Osaka, Japan) and E-Magic Finder Deluxe (S-Denti, Cheonan, Korea). After access preparation, the teeth were embedded in a saline-mixed alginate model. Canal lengths of each tooth were measured at "0.5" and "Apex" mark of the apex locators, respectively so that each tooth had two measurements from 0.5 and Apex points. The file was fixed at final measurement using a glass ionomer cement. The apical 4 mm from the apex was exposed to measure the distance from the file tip to the major apical foramen of each tooth. Average distances and standard deviations were used to evaluate the consistency. Results showed that all measurements of both Root ZX and E-Magic Finder located the major foramen the range of ± 0.5 mm level. Both apex locators showed better consistency at Apex mark than at 0.5 mark. The average distance of file tip-major foramen was - 0.18 mm at 0.5 mark and - 0.07 mm at Apex mark in Root ZX, - 0.25 mm at 0.5 mark and - 0.02 mm at Apex mark in E-Magic Finder. Standard deviation was 0.21 at 0.5 mark and 0.12 at Apex mark in Root ZX, 0.12 at 0.5 mark and 0.09 at Apex mark in E-Magic Finder.

컴포머의 불소 유리 및 항우식 효과에 관한 비교 연구

황규선,김종수,권순원 大韓小兒齒科學會 2002 大韓小兒齒科學會誌 Vol.29 No.1

소아치과 임상에서 널리 사용되고 있는 심미수복 재료인 컴포머의 불소 유리와 수복물 인접 법랑질에 대한 항우식 효과를 평가해 보고자 본 연구를 시행하였다. 음성대조군으로 복합레진인 Z-100을 Ⅰ군으로, 양성 대조군으로 글라스 아이오노머인 Fuji Ⅱ LC를 Ⅳ군으로 설정하였으며, 실험군으로는 Dyract AP를 Ⅱ군으로, F-2000을 Ⅲ군으로 설정하였다. 불소 유리량은 1일부터 7일까지는 매일, 그 후로는 각각 2일, 3일 또는 4일 간격으로 4주간 측정하였다. 또한 우전치의 순면에 동일한 와동을 형성하고 각 실험재료를 충전한 후 인공 우식을 유발시켜 항우식 효과 비교실험을 시행하였다. 음성 실험군인 Ⅰ군은 불소 유리를 하지 않았으며, Ⅳ군에서 전반적으로 가장 높은 불소 유리량을 나타냈다. Ⅱ군과 Ⅲ군은 Ⅳ군보다 전반적으로 낮은 불소 유리량을 보였으며, Ⅲ군은 Ⅱ군보다 불소 유리량이 많았다. 우식 병소의 관찰 결과 복합레진을 제외한 나머지 군에서는 수복물 인접부 우식 병소가 감소하는 양상을 나타냈으며, 컴포머 군인 F-2000과 Dyract AP 간에는 별다른 차이를 관찰할 수 없었다. The purpose of this study was to evaluate the fluoride release and anticariogenic effect of two compomers which is known to have been developed to improve the weak properties of glass ionomer cement and composite resin. Z-100 as composite resin(Group Ⅰ), Dyract AP(Group Ⅱ) and F-2000(Group Ⅲ) as compomer and Fuji Ⅱ LC as glass ionomer cement(Group Ⅳ) were used as test materials and evaluations were performed by pH/ISE meter for analyses of fluoride and polarizing microscope for analyses of anticariogenicity. The results can be summarized as follows : 1. The amount of fluoride release in compoite resin and compomer groups showed general pattern of decline during test period. Z-100 showed no fluoride release during test period. Fuji Ⅱ LC showed the highest fluoride release among test groups and then F-2000 were followed. 2. The least resistance to dimineralization was observed microscopically in Z-100 group which has no fluoride in it. The best resistance to dimineralization was observed microscopically in Fuji Ⅱ LC group and then compomer groups were followed. 3. Significant difference in lesion area was found between Fuji Ⅱ LC group and another groups. Significant difference in lesion area was found between compomer groups and Z-100 group. No significant difference in lesion area was found between Dyract AP group and F-2000 group. 4. Two compomers showed continual fluoride release and anticariogenic effect around filling materials. therefore, compomer was evaluated bery attractive restorative material in pediatric dentistry.

전기 화상 환자의 수술 전 평가,고압손상과 저압손상 비교

황정원,이정기,전영태,강종만,오용석,노규정,김현철 대한정맥마취학회 2004 정맥마취 Vol.8 No.1

신호인자와 목표치가 디지털 변수인 경우를 고려한 동적 파라미터 설계 적용(2)

송종대,황규완,배홍석 慶南專門大學 2000 論文集 Vol.28 No.1

Cone beam형 전산화단층영상을 이용한 영구치 치근과 근판의 형태 평가

홍종현,김규태,최용석,황의환 대한구강악안면방사선학회 2007 Imaging Science in Dentistry Vol.37 No.3

Purpose : To estimate the shape of root and pulp canal using a dental cone beam computed tomography (CBCT) and to evaluate the accuracy of imaging reformation. Materials and Methods : CBCT images were obtained with incisors, premolars, and molars as the destination by using PSR 9000N™ Dental CT system(Asahi Roentgen Ind. Co., Ltd, Kyoto, Japan) and i-CAT (Imaging Sciences International, Inc, USA) cone beam CT unit that have different kind of detector and field of view, and compared these with the shape and the size of actual root and root canal. Results : When the measuring value of cone beam computed tomography concerning to each root's bucco-lingual diameter and mesio-distal diameter was compared with the value of the actual root, it reveals an error range -0.49 ∼+0.63mm at PSR900N and -0.97 ∼+1.14mm at i-CAT (P>0.05). It was possible to identify and measure PSR 9000N™ Dental CT system to the limit 0.484±0.06mm (P>0.05) and i-CAT CBCT to the limit 0.86±0.09mm (P< 0.05) on estimating the size and the shape of root canal. Two kinds of CBCT images revealed the useful reproducibility to estimate the shape of root, but there was the difference to estimate the shape of root according to apparatus. The reproducibility of root shape in the image of three-dimensions at PSR 900N is low such as 0.65mm in a case of minute root canal. Conclusions : CBCT images revealed higher accuracy of the imaging reformation for root and pulp and clinically CBCT is a useful diagnostic tool for the assessment of root and canal. However, there are different qualities of imaging reformation according to CBCT apparatus and limitation of reproducibility for minute root canals.

능동필터 제어시스템을 위한 검출노이즈 저감방법에 관한 연구

최규하,채영민,황종규 건국대학교 산업기술연구원 1996 건국기술연구논문지 Vol.21 No.-

Active Power Filters(APF) have been developed for several years to solve the harmonics disturbance problems on power system networks. Control scheme of the proposed system is the Voltage Regulated Current Source Power Filter(VR-CSPF) that has a function to control the voltage of inverter output capacitor. Differential term is necessary to calculate voltage drop in VR-CSPF system. Since inverter switching action has occurred inherently in APF both switching or outside white nosis affect seriously at control signal. If control signal with added noise is differentiated, then high frequency noise becomes amplified more and more. Thus high frequency noise reduction method is needed for accurate operation. Hence this paper describes reduction method about amplified differential noise problems and its antinoise performances at VR-CSPF control system are studied by simulation and experiment

성인 급성 신부전의 원인 및 예후인자 분석

구영선,장윤경,양종오,강민규,황평주,김종학,나기량,이강욱,신영태 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.2

Acute renal failure is a frequent complication in hospitalized patients and is strongly related to the mortality. The Clinical outcome and prognostic factors of acute renal failure(ARF) have been analyzed by many authors. The present study describes the etiologic and clinical aspects, as well as other factors related to mortality. All the patients suffering from acute renal failure admitted during the period of January 1993 - August 1998 were included in the study. The average age of the patients was 52±17 years and mortality rate was 24%. The causes of acute renal failure were hemorrhagic fever with renal syndrome(HFRS), sepsis, renal hypoperfusion, urinary tract obstruction, acute tubular necrosis, etc. The etiology of ARF was a significant prognostic factor on mortality in ARF. Other significant prognostic factors were oliguria, organ failure, use of vasoconstrictors, hypotension, serum bicarbonate, premorbid conditions, sepsis, neurologic complications, gastrointestinal bleeding. On the other hands, operation, sex, anemia, thrombocytopenia, hypoalbuminemia, BUN, serum creatinine, and hyperkalemia were not significant factors for the mortality. We conclude that major prognostic factors of acute renal failure arc premorbid conditions, sepsis and multiorgan failure, and they are responsible for persistent high mortality of acute renal failure despite of advances of medical care.

Design of PRT Operating System based Interlocking between Virtual and Real Environment

Jong-Gyu Hwang,Baek-Hyun Kim,Seok-Won Kang,Yoon-Seop Byun,Joo-Hwan Um,Rak-Gyo Jeong 제어로봇시스템학회 2013 제어로봇시스템학회 국제학술대회 논문집 Vol.2013 No.10

Unlike existing general railways, PRT system is the new urban transit system which is operated non-stop to the destination of passengers on an on-demand basis by being operated in the method of off-line station based on operation lines in the form of complex networks. This PRT system is the new means of tranportion that was proposed conceptually long time ago and is being test-operated at some sites in some foreign countries currently. In Korea also, studies on this PRT system which is the new means of tranportion with a new concept were started, and this paper explains contents of design on operation system of PRT system as one of them. Especially, this paper explains contents of design on PRT operation control system through linkage of virtual environment to the real environment in accordance with the impossibility of securing physical spaces and manufacturing multiple vehicles in developing the new means of tranportion.

Locomotive Scheduling Using Constraint Satisfaction Problems Programming Technique

Jong-Gyu Hwang,Jong-Woo Lee,Yong-Jin Park 대한전기학회 2004 KIEE International Transactions on Electrical Mach Vol.4-B No.1