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.

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

전력 역변환장치 주요발열부의 열 저감 시스템 변위에 따른 냉각 특성해석

김민석,김용재,Kim, Min-Seok,Kim, Yong-Jae 한국전자통신학회 2015 한국전자통신학회 논문지 Vol.10 No.2

신재생에너지용 발전 시스템은 모듈, 직류 전력을 교류 전력으로 변환시키는 전력 역변환장치, 전력흐름을 제어하고 계통 연계를 담당하는 제어장치로 구성된다. 이러한 시스템은 일사량이 많은 여름철 및 낮 시간에 가장 많은 직류전력을 생산하지만 계통의 연계를 위해 필수적인 전력 역변환장치는 특정 온도 이상으로 상승하면 효율이 급격히 감소하게 된다. 따라서 열전소자를 부착한 열 저감 시스템을 제안하고 가장 발열이 심한 구간을 선정하여 사용개수 및 위치에 따른 온도 특성 해석을 통해 최적 모델을 도출하고자 한다. Power system for renewable energy is composed of module, transform DC power into AC power inverter, control power flow and device for a charge of the grid-connected. Power system for renewable energy produce the most DC power, when this system is much insolation in summer and daytime. But if the certain temperature rises above, the essential grid-connected power inverter is take a nose dive. There, in this paper, we propose an improved reduction of heating system. In addition, selection of the most serious heat region and through analysis of temperature characteristics according to location and distance derive the optimal model.

유완소(劉完素)의 중풍론(中風論)에 관(關)한 고찰(考察)

김민석,정승현,신길조,이원철,Kim, Min-Seok,Jung, Seung-Hyun,Shin, Gil-Cho,Lee, Won-Chul 대한한방내과학회 1997 大韓韓方內科學會誌 Vol.18 No.1

In this study, the purpose was to consider the conception, the causes, the pathology, the treatment and the prescription of 'Zhong Feng(中風)' through Liu Wan-Su's works. The results are obtained as fallows. First, Liu Wan-Su regarded Zhong Feng(中風) as 'Feng Re(風熱)'. He thought the causes and the pathology of Zhong Feng(中風) that pathologically fever was due to excess of feelings and 'Heart-fire(心火)', was due to intemperate living, so he thought the leading causes of Zhong Feng(中風) were Feng Re(風熱) and Heart-fire(心火) and emphasized the internal causes of Zhong Feng(中風). But he excluded absolutely external causes. He also insisted that Feng Re(風熱) was cause in a fat and a thin person. Second, according to symptom of the limbs and 'Jiu Qiao(九竅)', he classified Zhong Feng(中風) into 'Zhong Fu(中腑)' and 'Zhong Zang(中臟)'. And in the treatment of Zhong Feng(中風), the three principle was set up that 'Sweating .method(發表法)' in the case of Zhong Fu(中腑), 'Passing method(通滯法)' in Zhong Zang(中臟) and 'Nutrient method(養筋法)', in case that both symptom would not revealed. And in the prescription of Zhong Feng(中風), he presented 'Xumingtang(續命湯)', 'Sanhuatang(三化湯)' and 'Daqinfantang(大秦?湯)' to them each.

상호운용을 지원하는 코바 기반 공간 데이터 제공자의 설계 및 구현

김민석,안경환,홍봉희,Kim, Min-Seok,An, Kyoung-Hwan,Hong, Bong-Hee 한국공간정보학회 1999 개방형지리정보시스템학회 논문지 = Journal of the Korea Open Geogr Vol.1 No.2

CORBA와 같은 분산 컴퓨팅 환경에서 이종의 시스템 및 데이타베이스들의 통합을 위해 기존에는 포장자(wrapper)를 사용하였다. 이러한 여러 분야에 적용되는 포장자들 중에는 클라이언트에게 공통의 인터페이스를 제공하는 공간 데이타 제공자가 있다. 기존에는 공간 데이타 제공자를 데이타 소스별로 작성해야 하기 때문에 중복 구현과 구현 후의 변경 확장에 대한 문제가 있다. 이 논문에서는 공간 데이타 세공자의 재사용과 확장성을 위해 독립 포장자 객체와 종속 포장자 객체의 두개의 층으로 이루어진 새로운 구조를 제시한다. 종속 포장자 객체는 각 데이타소스에 대한 공간 데이타 작성시에 새로이 작성되야 하는 객체이고, 독립포장자 객체는 재사용될 수 있는 객체를 말한다. 또한 이 논문에서는 미들웨어에서 질의 처리 결과 유지 방법에 따른 구현 방법론을 제시한다. 질의 결과 유지 방법에는 질의 결과를 데이타로 유지하는 방법과 CORBA 객체로 변환하여 유지하는 방법으로 나뉘어진다. 각 방법에 대한 성능 평가 결과 CORBA 객체를 생성하는 방법의 비용이 상당히 높은 것을 알 수 있다. In distributed computing platforms like CORBA, wrappers are used to integrate heterogeneous systems or databases. A spatial data provider is one of the wrappers because it provides clients with uniform access interfaces to diverse data sources. The individual implementation of spatial data providers for each of different data sources is not efficient because of redundant coding of the wrapper modules. This paper presents a new architecture of the spatial data provider which consists of two layered objects : independent wrapper components and dependent wrapper components. Independent wrapper components would be reused for implementing a new data provider for a new data source, which dependent wrapper components should be newly coded for every data source. This paper furthermore discussed the issues of implementing the representation of query results in the middleware. There are two methods of keeping query results in the middleware. One is to keep query results as non-CORBA objects and the other is to transform query results into CORBA objects. The evaluation of the above two methods shows that the cost of making CORBA objects is very expensive.

승차감 관련 주관평가와 객관평가의 상관성 연구

김민석,김연태,문원길,안세진,유완석,Kim, Min-Seok,Kim, Yon-Tae,Moon, Won-Kil,Ahn, Se-Jin,Yoo, Wan-Suk 한국자동차공학회 2007 한국 자동차공학회논문집 Vol.15 No.5

In order to compare subjective and objective assessments, a passenger car was driven at several speeds over several road profiles. To measure the acceleration signals experienced by the seated subject who provided an subjective assessment, four triaxial translational accelerometers and one triaxial gyro sensor were mounted on the steering wheel and on the passenger seat and floor, respectively. Correlations were determined between the measured accelerations and the subjective assessments of 3 expert subjects and 9 general subjects using psychophysical power law.

Prone Breast Phantom을 이용한 couch 산란영향 평가

김민석,전수동,배선명,백금문,송흥권,Kim, Min Seok,Jeon, Soo Dong,Bae, Sun Myeong,Baek, Geum Mun,Song, Heung Gwon 대한방사선치료학회 2017 대한방사선치료학회지 Vol.29 No.2

목 적: 유방암 환자의 방사선치료 시 엎드린 자세를 적용하면 폐와 심장에 들어가는 선량을 줄일 수 있다. 하지만 빔 방향에 포함되는 couch의 영향으로 피부선량 증가 및 심부선량이 감소한다. 따라서 본 실험에서는 air gap을 이용해서 couch로 인한 영향을 줄일 수 있는 방법을 알아보고자 하였다. 대상 및 방법: 본원에서 치료 받은 유방암 환자의 전산화단층영상을 바탕으로 3D 프린터(Builder Extreme 1000)를 이용하여 체적을 동일하게 묘사한 인체모형을 제작하였다. 제작한 인체모형을 전산화단층촬영하고 전산화치료계획시스템(Eclipse 13.6, Varian, USA)을 이용하여 6MV, Field-in-Field technique을 이용한 200 cGy/fx의 치료계획을 수립하였다. 피부선량 측정을 위해 내, 외측 4 지점(Med 1, Med 2, Lat 1, Lat 2)에서 광자극발광선량계(Optically Stimulated Luminescence Detector, OSLD)를 이용한 측정을 진행하였고, 심부선량 측정을 위해 유방의 전면과 후면의 2 지점(Anterior, Posterior)에서 FC65-G ion-chamber를 이용한 측정을 하였다. Couch와 인체모형 사이의 air gap(기준 3 cm)을 1 cm 씩 총 6 cm까지 증가시켜가며 측정하였으며 치료계획 선량을 기준으로 평가하였다. 결 과: 피부선량 측정 결과 외측 지점은 치료계획과 비교하여 ${\pm}5%$ 이내의 유사한 값을 보였다. 내측 1 지점은 air gap이 증가할수록 감소하며 3 cm 이상부터 7 % 이상 감소하였고, 내측 2 지점은 4 % 이상 감소하였다. 심부선량 측정 결과 후면 지점은 air gap 차이에 의한 선량변화가 ${\pm}1%$ 이내의 값을 보였다. 전면 지점의 선량은 air gap이 증가할수록 높아지며 3 cm 이상부터 치료계획 보다 4 % 증가한 값을 보였다. 결 론: 본 실험을 통해 couch와 인체모형 사이의 air gap을 특정 거리까지 증가시켰을 때 couch로 인한 피부선량과 심부선량의 영향이 감소함을 확인하였다. 따라서 유방암 환자에 대한 치료 전 선량평가를 진행하여 각 환자에게 최적의 air gap을 적용한다면 피부보효 효과를 높일 수 있고, 정확한 심부선량의 전달이 가능할 것으로 사료된다. Purpose: The purpose of this study is to evaluate the dosimetric effects of couch attenuation and air gaps using 3D phantom for prone breast radiation therapy. Materials and method: A 3D printer(Builder Extreme 1000) and computed tomography (CT) images of a breast cancer patient were used to manufacture the customized breast phantom. Eclipse External Beam Planning 13.6 (Varian Medical Systems Palo Alto, CA, USA) was used to create the treatment plan with a dose of 200 cGy per fraction with 6 MV energy. The Optically Stimulated Luminescence Detector(OSLD) was used to measure the skin dose at four points (Med 1, Med 2, Lat 1, Lat 2) on the 3D phantom and ion-chamber (FC65-G) were used to perform the in-vivo dosimetry at the two points (Anterior, Posterior). The Skin dose and in-vivo dosimetry were measured with reference air gap (3 cm) and increased air gaps (1, 2, 3, 4, 5, 6 cm) from reference distance between the couch and 3D phantom. Results: As a result, measurement for the skin dose at lateral point showed a similar value within ${\pm}4%$ compared to the plan. While the air gap increased, skin dose at medial 1 was reduced. And it was also reduced over 7 % when the air gap was more than 3 cm compared to radiation therapy plan. At medial 2 it was reduced over 4 % as well. The changes of dose from variety of the air gap showed similar value within ${\pm}1%$ at posterior. As the air gap was increased, the dose at anterior was also increased and it was increased by 1 % from the air gap distance more than 3 cm. Conclusion: Dosimetrical measurement using 3D phantom is very useful to evaluate the dosimetric effects of couch attenuation and air gaps for prone breast radiation therapy. And it is possible to reduce the skin dose and increase the accuracy of the radiation dose delivery by appling the optimized air gap.

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.

대각공분산 GMM에 최적인 선형변환을 이용한 강인한 화자식별

김민석,양일호,유하진,Kim, Min-Seok,Yang, Il-Ho,Yu, Ha-Jin 대한음성학회 2008 말소리 Vol.65 No.-

We have been building a text-independent speaker recognition system that is robust to unknown channel and noise environments. In this paper, we propose a linear transformation to obtain robust features. The transformation is optimized to maximize the distances between the Gaussian mixtures. We use rotation of the axes, to cope with the problem of scaling the transformation matrix. The proposed transformation is similar to PCA or LDA, but can achieve better result in some special cases where PCA and LDA can not work properly. We use YOHO database to evaluate the proposed method and compare the result with PCA and LDA. The results show that the proposed method outperforms all the baseline, PCA and LDA.

SiOCH 박막의 열처리에 따른 전기적인 특성

김민석,황창수,김홍배,Kim, Min-Seok,Hwang, Chang-Su,Kim, Hong-Bae 한국전기전자재료학회 2008 전기전자재료 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.