편평세포암종 임파절 전이에 대한 인공 신경망 시스템의 진단능 평가

허민석,박태원,박상욱,유동수,이삼선,최순철 大韓口腔顎顔面 放射線學會 1999 Imaging Science in Dentistry Vol.29 No.1

Purpose: The purpose of this study was to evaluate cervical lymph node metastasis of oral squamous cell carcinoma patients by MRI film and neural network system. Materials and Methods: The oral squamous cell carcinoma patients(21 patients, 59 lymph nodes) who have visited SNU hospital and been taken by MRI, were included in this study. Neck dissection operations were done and all of the cervical lymph nodes were confirmed with biopsy. In MR images, each lymph node were evaluated by using 6 MR imaging criteria(size, roundness, heterogeneity, rim enhancement, central necrosis, grouping) respectively. Positive predictive value, negative predictive value, and accuracy of each MR imaging criteria were calculated. At neural network system, the layers of neural network system consisted of 10 input layer units, 10 hidden layer units and 1 output layer unit. 6 MR imaging criteria previously described and 4 MR imaging criteria (site I-node level II and submandibular area, site II-other node level, shape I-oval, shape II-bean) were included for input layer units. The training files were made of 39 lymph nodes(24 metastatic lymph nodes, 10 non-metastatic lymph nodes) and the testing files were made of other 20 lymph nodes(10 metastatic lymph nodes, 10 non-metastatic lymph nodes). The neural network system was trained with training files and the output level (metastatic index) of testing files were acquired. Diagnosis was decided according to 4 different standard metastatic index-68, 78, 88, 98 respectively and positive predictive values, negative predictive values and accuracy of each standard metastatic index were calculated. Results: In the diagnosis of using single MR imaging criteria, the rim enhancement criteria had highest positive predictive value (0.95) and the size criteria had highest negative predictive value(0.77). In the diagnosis of using single MR imaging criteria, the highest accurate criteria was heterogeneity (accuracy : 0.81) and the lowest one was central necrosis (accuracy : 0.59). In the diagnosis of using neural network systems, the highest accurate standard metastatic index was 78, and that time, the accuracy was 0.90. Neural network system was more accurate than any other single MR imaging criteria in evaluating cervical lymph node metastasis. Conclusion: Neural network system has been shown to be more useful than any other single MR imaging criteria. In future, Neural network system will be powerful aiding tool in evaluating cervical node metastasis.

전압형 PWM 컨버터의 전압 센서리스 제어

허태원,신동률,안인모,우정인 동아대학교 정보기술연구소 2000 情報通信硏究所論文誌 Vol.8 No.1

This paper presents a control scheme for a three-phase PWM converter system without any voltage sensors. Two input currents and one load current are measured. In a general PWM converter system, the required AC input and DC output voltage values in order to control the converter are estimated using the differential equations of the converter from the measured input currents and load current values in the switch modes of the converter circuit. The PI controller is used as DC voltage controller and sinusoidal tracking controller which tracks directly AC input current is used as input current controller. The proposed method is verified by simulations. This paper describes the estimation method and configuration of the controller, and discusses steady state and transient performances of the converter.

Correction: Direct characterization of graphene doping state by <i>in situ</i> photoemission spectroscopy with Ar gas cluster ion beam sputtering

Yun, Dong-Jin,Kim, Seyun,Jung, Changhoon,Lee, Chang-Seok,Sohn, Hiesang,Won, Jung Yeon,Kim, Yong Su,Chung, JaeGwan,Heo, Sung,Kim, Seong Heon,Seol, Minsu,Shin, Weon Ho The Royal Society of Chemistry 2018 Physical chemistry chemical physics Vol.20 No.4

<P>Correction for ‘Direct characterization of graphene doping state by <I>in situ</I> photoemission spectroscopy with Ar gas cluster ion beam sputtering’ by Dong-Jin Yun <I>et al.</I>, <I>Phys. Chem. Chem. Phys.</I>, 2018, 20, 615-622.</P>

비인강을 침범한 관통성 이물 2예

박동준,박상유,허원,최해명 연세대학교 원주의과대학 2000 원주의대논문집 Vol.13 No.1

당뇨병성 합병증을 가진 환자에서 혈증 Erythropoietin 농도

김동규,유기동,허광식,김상용,윤성호,조영신,권용은,김태원,김건영,정종훈,배학연 조선의대 1998 The Medical Journal of Chosun University Vol.23 No.1

당뇨병성 합병증을 가진 환자에서 혈중 Erythropoietin 농도

김동규,유기동,허광식,김상용,윤성호,조영신,권용은,김태원,김건영,정종훈,배학연 朝鮮大學校 附設 醫學硏究所 1998 The Medical Journal of Chosun University Vol.23 No.1

연구 배경 : 고혈당성에 의한 산화환원반응 이상(가저산소증)이 조절 되지않는 당뇨병의 특징으로 혈관과 신경 기능에 대한 진성 저산소증의 효과와 유사하며, 당뇨 합병증의 병태생리에 중요한 역할을 한다. 고혈당이 있는 인슐린 비의존형 당뇨병 환자에서 인슐린 수준이 정상이듯이, 빈혈이 있는 당뇨병 환자에서 EPO의 농도는 실제 혈색소 농도의 감소비율과 차이가 있을 것이라 추측된다. Friedman 등은 당뇨병성 합병증 원인 인자로 가저산소증(pseudohypoxia) 또는 저산소증(hypoxia)을 제기하였고 이런 인자들이 EPO의 상대적 또는 절대적 결핍에 의한 것임을 보고하였다. 방법 : EPO-Trac^(TM 125)I RIA kit을 이용하여 방사면역측정법으로 EPO 수준을 검사하였다. 전혈 3㎖을 5-10㎖ 시험관에 정맥 채혈하였으며, 용혈과 장기간의 보존을 위하여 원심분리를 즉시 시행하여 혈청을 영하 200C에서 냉동 보관 후 일괄적으로 검사 결과를 얻었다. 결과 : 1996년 9월부터 1997년 2월까지 조선대학교 부속병원 내과에 입원한 2형 당뇨병 환자 63례를 대상으로 하여 다음과 같은 결과를 얻었다. 1) 당뇨병성 합병증이 없는 군과 있는 군간의 혈색소, 혈중 EPO농도의 차이는 유의한 차이가 있었으며 혈색소의 감소율보다 혈중 EPO의 감소율이 더 높았다. 2) 당뇨병성 망막증의 유무에 따른 혈색소 농도의 차이는 유의한 차이가 없었으나 혈중 EPO농도는 유의한 차이가 있었다. 증식성군에서만 혈중 EPO의 감소비율이 혈색소에 비해 높았다. 3) 당뇨병성 신증의 유무에 따른 혈색소, 혈중 EPO농도는 유의한 차이가 있었고 혈색소 감소율에 비해 EPO농도의 감소율이 높았다. 신증의 중증도에 따른 혈색소, EPO의 차이는 미세알부민뇨군을 제외하고는 유의한 차이를 보였고 혈색소 감소율에 비해 EPO의 감소율이 더높았다. 4) 당뇨병성 신경병증의 유무에 따른 혈색소 농도의 차이는 유의한 차이가 없었으며 EPO농도는 유의한 차이를 보였다. 혈색소와 EPO의 감소비율은 비슷하였다. 신경병증의 중등도에 따른 혈색소와 EPO농도의 변화는 유의한 차이가 없었으나 stage 3에서는 혈색소감소율보다 EPO감소율이 더높았다. 결론 : 당뇨병성 합병증을 가진 환자에서 빈혈의 정도는 대부분 혈청 EPO치의 절대적 감소에 의함을 간접적으로 밝혀낼 수 있었으며 차후 더 많은 대상으로 비교 분석이 필요하리라 사료된다. Background: Hyperglycemic-induced redox(pseudohypoxia) imbalance is a characteristic feature of poorly controlled diabetes that mimics the effects of true hypoxia on vascular and neural functions and plays an important role on the pathogenesis of diabetic complications. As is true for apparently "normal" insulin levels typically found in NIDDM even in the presence of hyperglycemia, a "normal" erythropoietin level in an anemic diabetic subject may be disproportionally low for the actual red cell mass. Therefore, Friedman et al suggested that pseudohypoxia or hypoxia as an etiological factor of diabetic complications are due to absolute or relative erythropoietin deficiency Method: EPO-TracTM 125I RIA kit was used for the quantitative determination of erythropoietin(EPO) in serum by radioimmunoassay. An adequate sample of blood (3ml whole blood) was collected aseptically by venipuncture in a 5~10ml glass tube to yield a minimum of 400 L of serum per assay. The serum was promptly removed from the clot by centrifugation in order to avoid hemolysis. Then to increase its storage time it was frozen at -200C in a nonself defrosting freezer. Finally, tests were undertaken simultaneously Results We studied 63 cases with diabetes mellitus, who were admitted to Chosun University Hospital from September, 1996 to February, 1997 at the Department of Internal Medicine. We defined the control group, as diabetic patients who did not have anemia(<13mg/dl), diabetic complications(retinopathy, nephropathy, neuropathy) and the remainders were defined as the experimental group(we excluded anemic patients, who had secondary causes of anemia and diabetic patients with end stage renal disease)Data were as follow 1) The relationship of Hb and the 24hr urine protein between diabetic patients with and without complications significantly differed(p=0.02, < 0.001 respectively), but the Hb level was poorly related between diabetic patients with and without retinopathy(except in preproliferative, proliferative subgroups) and neuropathy. 2) Subgroups of patients with diabetic complications had higher 24hr urine protein than patients without diabetic complications, except stage I diabetic neuropathy 3) The EPO level was significantly different between diabetic patients with and without complications. 4) The correlation between EPO and Hb was significantly different, especially in diabetic patients with retinopathy and nephropathy according to severity of diabetic complications, compared with patients who did not have diabetic complications such as retinopathy and nephropathy. Conclusion: We know that anemia induced by diabetic complications is due to relative EPO deficiency than absolute EPO deficiency, and further evaluation and studies are needed on many cases in the future

태양광 발전전력을 입력으로한 DC/DC 컨버터의 일정출력제어

조용길,허태원,신동률,조광승,우정인 東亞大學校 大學院 2000 大學院論文集 Vol.25 No.-

In this paper, it is proposed to constant power control of solar power system. The solar power system has disadvantage that low power density and variable power output. Proposed strategy is controled by DC/DC converter using phase shift PWM and I-PD type control applying type 1 digital system. The validity of proposed control strategy is verified from simulations results using PSIM.

신경회로망을 이용한 원공 결함 패턴 인식에 관한 연구

홍순혁,이동우,허건,조석수,주원식 동아대학교 생산기술연구소 2000 生産技術硏究所硏究論文集 Vol.5 No.1

Ultrasonic inspection of defects has been focused on the existence of defect in structural material and need has much time and expenses in inspecting all the coordinates (x, y) on material surface. Neural networks is information processing system modeling human brain and can have an application to coordinates (x, y) of defects by multi-point inspection method. Ultrasonic inspection modeling is optimized by neural networks which makes defect echo, back-wall echo and ultrasonic transducer units of input layer and absolute and relative coordinates of defects and defect pattern units of output layer. This method can predict coordinates (x, y) of defects within engineering estimated mean error Ψ.

영구자석형 선형동기전동기의 위치제어를 위한 가변구조 벡터제어 시스템에 관한 연구

우정인,신동률,허태원,조광승 東亞大學校 2000 東亞論叢 Vol.37 No.-

OA, FA기기 등에 에너지 밀집도를 높일 수 있는 영구자석형 선형동기전동기(PMLSM)를 적용하고자하는 연구가 활발하게 진행되고 있다. PMLSM은 파라메터의 변동과 외부의 외란에 매우 민감하다. 이러한 PMLSM의 구동에 있어서 요구되는 것은 파라미터 변동과 부하 토크 외란에 견실하면서 빠른 응답속도를 가지는 제어기이다. 따라서, 본 논문에서는 PMLSM의 위치제어를 위한 가변구조 벡터제어시스템을 제안하고자 한다. 파라메터 변동과 외부외란의 변화에 강인한 가변구조 기법을 이용한 슬라이딩 모드제어의 타당성을 시뮬레이션을 통하여 검증하고자 한다.

경골 분절 골절의 골수강내 금속정을 이용한 수술적 치료

하상호,유재원,이상홍,신동민,표영배,허민 조선대학교 1994 The Medical Journal of Chosun University Vol.19 No.2

The Fracture of the tibia is the most common on fracture of the long bone and has high complication rates due to it's anatomical property. Segmental fractures are characterized by two or more fractures on different levels of the shaft with an intermediate segment. In addition to general characteristics of tibial fracture, segmental fractures are commonly combined with extensive soft tissue injury comminution and displacement with poor blood supply in it's intermediate segment. Recently, closed intramedullary nailing under the image intensifier has been widely used and its good results have been reported. The purpose of this study is to compart the bony union, functional result and complication between Ender nail and interlocking nail which we treated with intramedullary nailing in 20 segmental tibial fractures of 19 patients from 1990 to 1991. Minimum follow up period was 12 months. The results were as follows : 1. The most common type of fractures was Melis type Ⅰ. 2. All fractures were united and average union time was 24.9 weeks. 3. The major complications were delayed union (6 cases) joint stiffness (6 cases), superficial infection (3 cases), and angular deformity (2 cases). The complication rate in Ender nail was higher than Interlocking nail. 4. According to the criteria of functional results by Klemm and Borner. we obtained a 87.5% of excellent and good resulted in Ender nailing group and 91.7% of excellent and good results in Interlocking nail group.