복시환자의 임상양상

김민석,최진,김정훈,김재석,이주화,Min Seok Kim,Jin Choi,Jung Hoon Kim,Jae Suk Kim,Joo Hwa Lee 대한안과학회 2013 대한안과학회지 Vol.54 No.11

Purpose: To evaluate the clinical features, causes and outcomes of patients with diplopia. Methods: All patients presenting with diplopia from October 2010 to March 2012 and followed up for more than 3 months were retrospectively investigated. Results: During the study period, 59 patients with diplopia were identified. There were 42 males and 17 females with an average age of 50 years. Binocular diplopia accounted for 54 cases (92%) and 5 cases (8%) had monocular diplopia. Cranial nerve palsies were the most common cause of binocular diplopia (28 cases, 52%). Within the cranial nerve palsies group, 14 cases (50%) were accompanied by hypertension or diabetes mellitus. Binocular diplopia spontaneously resolved in 35 cases (65%) by 3 months rising to 41 cases (76%) by 7 months. Thirteen (93%) out of 14 cases of cranial nerve palsies with hypertension or diabetes resolved spontaneously by 3 months. Conclusions: Binocular diplopia was caused most commonly by cranial nerve palsy and resolved after 3 months in 65% of patients. A spontaneous recovery from diplopia was observed after 3 months in 93% of patients with cranial nerve palsies and microvascular disease such as hypertension or diabetes. Therefore, the initial observation without additional treatment would be sufficient in these patients. J Korean Ophthalmol Soc 2013;54(11):1772-1777

열처리 및 단조조건에 따른 알루미늄 6056 소재의 특성변화 및 자동차의 피스톤 블록 설계

김민석,정병덕,박효영,최정묵,김정민,박준식,Kim, Min Seok,Jung, Hyung Duck,Park, Hyo young,Choi, Jeong Mook,Kim, Jeong Min,Park, Joon Sik 한국재료학회 2015 한국재료학회지 Vol.25 No.10

The mechanical properties and microstructures of Aluminum 6056 alloys were investigated for their use in the fabrication of a piton block. The EN-AW6056 alloys exhibited a tensile strength of 375 MPa for a solution treatment temperature of $550^{\circ}C$ for 2 h followed by an aging treatment at $190^{\circ}C$ for 4 h. The microstructures of the heat treated specimen showed that the $Mg_2Si$ phase with a size of 3~5 um was dispersed throughout the aluminum matrix when the heat treatment was done. Moreover, in order to identify the forgeability of the specimen, upsetting tests were done. For up to 80 % of the upsetting ratio, the specimen maintained its original shape, and at above 80 % of the upsetting ratio, the specimen underwent crack development. The specimen was successfully forged without any defects with the examined material conditions. The material conditions together with the forging conditions are discussed in terms of the microstructures and mechanical properties.

영상처리 기법을 이용한 샥-하트만 파면 센서의 측정범위 확장에 대한 연구

김민석,김지연,엄태경,윤성기,이준호,Kim, Min-Seok,Kim, Ji-Yeon,Uhm, Tae-Kyung,Youn, Sung-Kie,Lee, Jun-Ho 한국광학회 2007 한국광학회지 Vol.18 No.6

샥-하트만 센서는 렌즐릿 배열을 이용하여 파면의 국부적인 기지를 계산하고 이로부터 파면의 왜곡된 정도를 측정하는 파면측정 센서이다. 일반적으로 하나의 점영상에 대한 중심점을 추출하여 기준 점영상의 중심점에 대한 상대적 이동량을 통해 파면의 국부 기울기를 계산, 전체 파면을 복원하는 원리이다. 따라서 하나의 점영상에 대한 정확한 중심점의 추출을 위하여 해당하는 하부개구 내에 점영상이 존재하여야 한다. 하지만 큰 기울기의 파면이 샥-하트만 센서에 입사하게 되면 측정범위를 벗어나게 되어 일반적인 방법으로는 파면의 국부적인 기울기를 계산할 수 없게 되는 문제점이 있다. 이를 해결하기 위해 특정 측정시스템에만 국한된 알고리즘이 아닌 모든 파면에 대해 측정 가능하면서도 추가적인 장비 없이 일반적인 샥-하트만 파면 센서가 지니고 있는 측정범위의 한계를 극복할 수 있는 알고리즘이 필요하다. 본 연구에서는 영상처리 기법을 이용하여 각 점영상에 대한 유동적인 탐색영역을 설정하고 이러한 탐색영역 내에서 중심점을 추출하는 방법을 제안하였다. 또 점영상 대응법을 적용하여 측정 점영상과 기준 점영상을 일대일 대응시킴으로써 전체 측정파면을 복원할 수 있는 알고리즘을 제안함으로써 측정범위에 제한 없이 파면왜곡을 측정할 수 있는 측정방법을 제시하였다. 이렇게 제안된 알고리즘을 샥-하트만 파면 센서 시스템을 이용한 초점벗어남 측정실험을 통하여 검증하였다. The Shack-Hartmann wavefront sensor is composed of a lenslet array generating the spot images from which local slope is calculated and overall wavefront is measured. Generally the principle of wavefront reconstruction is that the spot centroid of each lenslet array is calculated from pixel intensity values in its subaperture, and then overall wavefront is reconstructed by the local slope of the wavefront obtained by deviations from reference positions. Hence the spot image of each lenslet array has to remain in its subaperture for exact measurement of the wavefront. However the spot of each lenslet array deviates from its subaperture area when a wavefront with large local slopes enters the Shack-Hartmann sensor. In this research, we propose a spot image searching method that finds the area of each measured spot image flexibly and determines the centroid of each spot in its area Also the algorithms that match these centroids to their reference points unequivocally, even if some of them are situated off the allocated subaperture, are proposed. Finally we verify the proposed algorithm with the test of a defocus measurement through experimental setup for the Shack-Hartmann wavefront sensor. It has been shown that the proposed algorithm can expand the dynamic range without additional devices.

강우의 시간해상도와 자료기간에 따른 설계홍수량의 변동성

김민석,이정환,문영일,Kim, Min-Seok,Lee, Jung-Hwan,Moon, Young-Il 한국수자원학회 2018 한국수자원학회논문집 Vol.51 No.7

대부분의 수문분석은 시 단위 강우를 기반으로 확률강우량과 강우시간분포를 산정하고, 확률강우량과 강우시간분포의 자료기간을 달리 적용하는 방법으로 강우-유출분석을 수행하고 있다. 본 연구에서는 자료형태(시 단위와 분 단위 강우자료)와 확률강우량과 강우시간분포의 다른 자료기간 적용에 따른 설계홍수량 변화를 정량화 하고자, 자료형태와 자료기간에 따라 지점빈도해석을 통한 확률강우량 산정과 Huff의 4분위 방법을 통한 강우시간분포를 산정하였다. 또한, 확률강우량과 설계강우 시간분포의 자료기간을 달리 적용한 강우-유출분석으로 설계홍수량 변동분석을 실시하였다. 분석결과, 자료형태에서는 분 단위 강우가 시 단위 강우보다 더욱 정확하고 효과적인 강우분석을 수행할 수 있는 것으로 나타났으며, 확률 강우량과 강우시간분포의 다른 자료기간을 적용하여 산정된 설계홍수량의 차 보다 자료형식에 따른 설계홍수량 결과가 보다 큰 차이를 보이는 것으로 나타났다. 이는 향후 분 단위 강우를 활용한 수문분석에 크게 기여할 것으로 판단된다. Most hydrological analysis such as probability rainfall and rainfall time distributions have typically carried out based on hourly rainfall and rainfall - runoff analysis have carried out by applying different periods of rainfall time distribution and probability rainfall. In this study, to quantify the change of design flood due to the data type (hourly and minutely rainfall data) and the probability rainfall and application of different data period to the rainfall time distribution, probability rainfall is calculated by point frequency analysis according to data type and period and rainfall time distribution was calculated by Huff's quartile distributions. In addition, the change analysis of design flood was carried out by rainfall - runoff analysis applying different data periods of design rainfall time distribution. and probability rainfall. As a result, rainfall analysis using minute rainfall data was more accurate and effective than using hourly rainfall data. And the design flood calculated by applying different data period of rainfall time distribution and probability rainfall made a large difference than by applying different data type. It is expected that this will contribute to the hydrological analysis using minutely rainfall.

당뇨망막병증에서 나비라스 레이저 시스템과 기존 범망막광응고술의 소요시간과 통증 비교

김민석,이성우,김재석,Min Seok Kim,Seong Woo Lee,Jae Suk Kim 대한안과학회 2014 대한안과학회지 Vol.55 No.8

Purpose: To compare the pain scale and time necessary for panretinal photocoagulation (PRP) between Navilas<sup><font size=`2`>Ⓡ</font> (OD-OS, Teltow, Germany) and conventional laser in diabetic retinopathy. Methods: Fifteen patients who required PRP for diabetic retinopathy were enrolled in the present study. PRP was performed using Navilas<sup><font size=`2`>Ⓡ</font> (5 x 5 array patterned system) in the superior, nasal and inferior areas, and using conventional laser at the temporal area 1 week later. Total time of laser application and number of laser shots were counted for calculating required time per 100 spots of each laser system. Immediately after the laser photocoagulation, patients were asked to quantify their pain on a visual analog pain scale (0 = no pain; 10 = worst pain). Results: PRP using Navilas<sup><font size=`2`>Ⓡ</font> required shorter time per 100 laser spots (27.7 sec vs. 102.0 sec, <em>p</em> < 0.001) and subjects had lower treatment-related pain than with the conventional laser system (3.3 vs. 6.9,<em> p</em> < 0.001). Conclusions: PRP using Navilas<sup><font size=`2`>Ⓡ</font> can be considered as an efficient method for improving patient and operator's comfort with faster laser application and lower treatment-related pain. J Korean Ophthalmol Soc 2014;55(8):1150-1154

SiOCH 박막의 열처리에 따른 전기적인 특성

김민석,황창수,김홍배,Kim, Min-Seok,Hwang, Chang-Su,Kim, Hong-Bae 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.12

The SiOCH films that low dielectric interlayer dielectric materials were deposited on p-type Si(100) substrates through the dissociation of BTMSM precursors with oxygen gas by using PECVD method. BTMSM precursor was introduced with the flow rates from 42 sccm to 60 sccm by 2 sccm step in the constant flow rate of 60 sccm $O_2$. SiOCH thin films were annealed at $450^{\circ}C$ for 30 minutes. The electrical property of SiOCH thin films was studied by MIS, Al/SiOCH/p-Si(100), structure. Annealed samples showed even greater reductions of the maximum capacitance and the dielectric constant of the SiOCH samples, owing to reductions of surface charge density. we confirmed this result with derivative of C-V characteristic, leakage current density. The maximum capacitance and leakage current density were respectively decreased about 4 pF, 60% after annealing. The average of low-k value is approximatly 2.07 after annealing.

대규모 자유도 문제의 구조해석을 위한 병렬 알고리즘

김민석,이지호,Kim, Min-Seok,Lee, Jee-Ho 한국전산구조공학회 2010 한국전산구조공학회논문집 Vol.23 No.5

본 논문에서는 대규모 자유도 시스템의 병렬처리를 위하여 2단계로 이루어진 영역분할법(Domain Decomposition Method) 기반의 병렬 알고리즘을 제안하였다. 분할된 영역의 내부 및 외부 경계를 상위영역문제로 정의하고 국부영역문제는 변위 경계조건이 모두 주어지는 분할영역에서의 Dirichlet 문제로 구성한다. 상위영역에서는 전체 상위영역에 대한 강성 행렬의 어셈블이 필요없는 반복법을 통하여 변위를 구하고, 이를 바탕으로 국부영역에서 Multi-Frontal Sparse Solver (MFSS)를 이용하여 변위를 계산한다. 상위영역문제의 연산에서 프로세서 간의 데이터 교환을 최소화하여 계산효율을 유지하며, 동시에 해석 가능한 자유도를 증대시키는 병렬 PCG(Preconditioned Conjugate Gradient)법 기반의 알고리즘을 개발하였다. 제안된 알고리즘을 적용하여 수치해석을 수행한 결과, 프로세서 수가 증가할수록 계산성능의 손실없이 해석 가능한 자유도가 비례하여 증가하는 선형 확장성을 관찰할 수 있었으며, 대규모 자유도 문제에 효과적으로 사용 가능함을 확인하였다. In this paper, an efficient two-level parallel domain decomposition algorithm is suggested to solve large-DOF structural problems. Each subdomain is composed of the coarse problem and local problem. In the coarse problem, displacements at coarse nodes are computed by the iterative method that does not need to assemble a stiffness matrix for the whole coarse problem. Then displacements at local nodes are computed by Multi-Frontal Sparse Solver. A parallel version of PCG(Preconditioned Conjugate Gradient Method) is developed to solve the coarse problem iteratively, which minimizes the data communication amount between processors to increase the possible problem DOF size while maintaining the computational efficiency. The test results show that the suggested algorithm provides scalability on computing performance and an efficient approach to solve large-DOF structural problems.

초소형 프로젝터를 위한 디지털 LCOS 마이크로 디스플레이의 계조 연구

김민석,강정원,Kim, Min-Seok,Kang, Jung-Won 한국반도체디스플레이기술학회 2010 반도체디스플레이기술학회지 Vol.9 No.2

A new SRAM pixel circuit with RESET Transistor of a LCOS display module was designed for a pico-projector application. A dual-block PWM method was also proposed to realize the field sequential color system having only one LCOS panel. 0.29 inch LCOS panel in SVGA resolution was fabricated and the proposed dual-block PWM method was tested with it. Discontinuity of brightness curve was caused due to multi-pulses and it was improved by the adoption of proper mapping table. With the proposed SRAM with RESET pixel circuit and dual-block PWM method, the test images were successfully demonstrated.

소아 환자에서 엡스타인-바 바이러스 뇌염에 동반된 양안 외향신경마비

김민석,최진,정재호,Kim Min Seok,Jin Choi,Jae Ho Jung 대한안과학회 2013 대한안과학회지 Vol.54 No.8

Purpose: To report 2 cases that presented with bilateral abducens nerve palsy associated with Epstein-Barr virus (EBV) encephalitis in children. Case summary: Case 1. A 14-month-old boy presented with fever and esodeviation of the left eye that started 5 days earlier. On the ophthalmic examination, 45-PD esotropia of the left eye and limitation of abduction in both eyes were observed. On neurological examination, there were no abnormalities. Serologic test and polymerase chain reaction (PCR) from cerebrospinal fluid (CSF) were positive for EBV. The patient was treated with systemic acyclovir and prednisolone. Part-time occlusion therapy of the right eye for 2 hours/day was also prescribed. The patient underwent a 6.5-millimeter recession of the medial rectus and a 6-millimeter resection of the lateral rectus on the left eye 7 months after the presentation. The patient showed orthotropia 1 week after the surgery without neurologic sequelae. Case 2. A 13-year-old boy presented with headaches and fever that started 5 days before and altered consciousness with seizures 2 days previously. Serological test for viral infection was normal, except for EBV, and CSF examination showed viral infection. After the patient recovered consciousness, he complained of diplopia. A 30-PD esotropia of his left eye with bilateral limitation of abduction was present. Alternating full-time occlusion of both eyes was prescribed. At 4 months after presentation, diplopia disappeared and the patient showed orthotropia without abduction limitation; however, anticonvulsants were prescribed to control seizures. Conclusions: In children, EBV encephalitis can be accompanied by acquired bilateral abducens nerve palsy. Residual nerve palsy and other neurologic sequelae can remain after several months.

학술발표회 초록 : ( 공정시스템 (2) ) ; 제철소에서의 LDG 배분 감시를 위한 전문가 시스템 개발

김민석,이인범,양대륙,장근수 ( Min Seok Kim,In Beum Lee,Dae Ryook Yang,Kun Soo Chang ) 한국화학공학회 1992 추계학술발표회 Vol.- No.-