이명의 유병률 및 이명유무에 따른 청력역치수준

이원철,최병철,오민화,박정일,김현욱,구정완 大韓産業醫學會 1999 대한직업환경의학회지 Vol.11 No.3

Objectives: In order to establish prevalence and characteristics of tinnitus and hearing thresholes according to tinnitus, this study was carried out. Methods: Nine hundred and thirty two subjects, undergone human dock or general health check-up and been in college, were surveyed to the questionnaire on the general characteristics, past medical histories, life styles, subjective symptoms about hearing, taking ototoxic drugs and were conducted on the hearing thresholds by pure tone audiometry. Results: Of the total population, 98 reported tinnitus, giving an overall prevalence of 10.5%, prevalence of tinnitus in the subjects with the factors influencing hearing thresholds were 17.4%, prevalence without the factors influencing hearing thresholds were 7.5%. Frequency of tinnitus of the total population was the highest in 'once per several months' (39.6%) and followed by 'once per several days'(29.7%), 'all day long' (16.5%) and 'several times per day' (14.3%). Complaint site of tinnitus was 41.8% in left ear or right ear, 39.6% in both ear and 18.7% in head. The 13.6% of the total subjects complained sleep disturbance. Hearing thresholds in the subjects without the factors influencing hearing thresholds tended to increase or decrease in 20 and 30 years old according to tinnitus, but those with tinnitus tended to increase more than those without tinnitus in 40 and 50 years old. Conclusions: Results also provide evidence that reports of tinnitus at the time of annual audiometric testing may be useful in identifying workers at greater risk for developing significant shifts in hearing thresholds. Awareness of the possible occurrence of tinnitus may encourage workers to cooperate more actively in a company hearing conservation programme.

Capsular serotypes, virulence-associated genes and antimicrobial susceptibility of <i>Streptococcus suis</i> isolates from pigs in Korea

OH, Sang-Ik,JEON, Albert Byungyun,JUNG, Byeong-Yeal,BYUN, Jae-Won,GOTTSCHALK, Marcelo,KIM, Aeran,KIM, Jong Wan,KIM, Ha-Young JAPANESE SOCIETY OF VETERINARY SCIENCE 2017 The Journal of veterinary medical science Vol.79 No.4

<P><I>Streptococcus suis</I> is an important pig pathogen with potential for human transmission. The serotype distributions and phenotypic characteristics vary over time and among regions; however, little is known about the characteristics of <I>S. suis</I> isolates in Korea. In this study, 240 <I>S. suis</I> isolates collected from pigs in Korea in 2009–2010 were serotyped by coagglutination tests, subsequently screened for three virulence-associated genes (<I>mrp</I>, <I>epf</I> and <I>sly</I>) and tested for antimicrobial susceptibility. As for 80 isolates, the serotypes of which were relevant to human infections, clonal complexes (CCs) were further identified by PCR. Serotype 3 was the most prevalent (15.8%), followed by serotype 2 (15.0%), with geographical variation for each serotype. Overall, 55.4% of the isolates carried <I>mrp</I>, whereas only 3.8% carried <I>epf.</I> CC25 was the most prevalent (41.3%) and was related to serotypes 2 and 9. The isolates showed higher susceptibility to ampicillin (93.4%) and ceftiofur (90.8%) than to the other antimicrobial agents tested. The highest resistance rate was observed to tetracycline (98.0%), followed by erythromycin (88.8%). In addition, the resistance to certain antimicrobials was significantly associated, in part, with virulence-associated genes or serotypes. Therefore, continuous characterization of <I>S. suis</I> is essential for the benefit of veterinary and human medicine.</P>

첨단제조기술 투자의 경제성 평가를 위한 위험조정할인율의 결정방법

오병완,조성구 동국대학교 산업기술연구원 1997 산업기술논문집 Vol.10 No.-

The Discounted Cash Flow(DCF) approach, which has been one of the most frequently used techniques to evaluate industrial investment opportunities, needs to be modified under new manufacturing environments involving high degree of uncertainty and risk. Risk is typically incorporated in DCF analysis in two ways: using certainty equivalent method or via Risk Adjusted Discount Rate(RADR). In this paper, we propose a method to determine RADR for economic evaluation of advanced manufacturing technologies, which are characterized by high initial investment costs and relatively long payback periods. To consider risk characterics of each investment alternative, the proposed method calculates period by period RADRs of each alternative using βcoefficient of capital asset pricing model. A computer simulation was performed to compare the proposed method with the existing ones. The results show that the DCF analysis using the proposed RADRs can be a more reasonable evaluation tool for advanced manufacturing technologies than the existing methods.

Evaluation of User Profile Construction Method by Fuzzy Inference

Byeong Man Kim,Sun-Ok Rho,Sang Yeop Oh,Hyun Ah Lee,Jong-Wan Kim 한국지능시스템학회 2008 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.8 No.3

To construct user profiles automatically, an extraction method for representative keywords from a set of documents is needed. In our previous works, we suggested such a method and showed its usefulness. Here, we apply it to the classification problem and observe how much it contributes to performance improvement. The method can be used as a linear document classifier with few modifications. So, we first evaluate its performance for that case. The method is also applicable to some non-linear classification methods such as GIS (Generalized Instance Set). In GIS algorithm, generalized instances are built from training documents by a generalization function and then the K-NN algorithm is applied to them, where the method can be used as a generalization function. For comparative works, two famous linear classification methods, Rocchio and Widrow-Hoff algorithms, are also used. Experimental results show that our method is better than the others for the case that only positive documents are considered, but not when negative documents are considered together.

Solid-state synthesis of Ti₂Nb₁₀O₂₉/reduced graphene oxide composites with enhanced lithium storage capability

Wang, Wan Lin,Oh, Byeong-Yun,Park, Ju-Young,Ki, Hangil,Jang, Jaewon,Lee, Gab-Yong,Gu, Hal-Bon,Ham, Moon-Ho Elsevier 2015 Journal of Power Sources Vol.300 No.-

<P><B>Abstract</B></P> <P>Owing to their multiple redox couples, titanium–niobium-based oxides are still considered promising candidates for use as anodes for safe, rechargeable lithium ion batteries with high energy and power densities. Titanium–niobium-based oxide electrodes have, however, exhibited relatively poor cycling performance as a result of pulverization. In this study, we report on a simple two-step solid-state reaction route for producing hybrid composites of Ti<SUB>2</SUB>Nb<SUB>10</SUB>O<SUB>29</SUB> (TNO) anchored on reduced graphene oxide (RGO), and the electrochemical performance of the resulting TNO/RGO composites. Solid-state reactions enable both the formation of TNO and the uniform distribution of RGO in the TNO/RGO composites. The TNO/RGO composites exhibited discharge and charge capacities of 261 and 256 mAh g<SUP>−1</SUP>, respectively, with much better cycling performance (182 mAh g<SUP>−1</SUP> after the 50th cycles) and rate capability (165 mAh g<SUP>−1</SUP> at a current density of 500 mA g<SUP>−1</SUP>) compared to the pure TNO.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hybrid composites of Ti<SUB>2</SUB>Nb<SUB>10</SUB>O<SUB>29</SUB> anchored on reduced graphene oxide were fabricated. </LI> <LI> A simple two-step solid-state reaction method was employed. </LI> <LI> The hybrid composites exhibited greatly improved electrochemical performance. </LI> </UL> </P>

장골의 골단 손상 양상에 대한 역학적 연구

박병문,박희완,오상훈,박상규 대한스포츠의학회 1998 대한스포츠의학회지 Vol.16 No.1

We have had more concern about the epidemiology of eiphyseal injuries, but only a few articles were available. We reviewed 136 children under 16 years of age who have had epiphyseal injuries concerning age, sex, location, causes, monthly incidence, common sites and the types of fractures. We also evaluated the realtionships between age, site and type. Epiphyseal injuries were predominant between 6 and 8 years of age. The monthly incidence was highest between June and August and boys were affected 2.4 times more than girl. The frequent causes were slip down, traffic accident, falling, sports injury and direct blow. Common sites were the distal humerus, the distal radius and the distal tibia, in that order. The upper extremity was affected 2.6 times more than the lower extremity, distal epiphyses were 4.9 times more common than proximal epiphyses in the same long bones and the right side was affected 1.4 times more than the left side. The most common type by Salter & Harris classification was type Ⅱ and the frequent sites of type Ⅰ, Ⅱ and Ⅳ were the distal humerus and type Ⅲ was the distal tibia. Epiphyseal injuries of the humerus and radius were predominant between 6 and 8 years of age and those of the tibia was predominant in the age group over 8 years of age.

The novel perovskite-type Ni-doped Sr_0.92Y_0.08TiO₃ catalyst as a reforming biogas (CH₄ +CO₂) for H₂ production

Kwon, Byeong Wan,Oh, Joo Hyeng,Kim, Ghun Sik,Yoon, Sung Pil,Han, Jonghee,Nam, Suk Woo,Ham, Hyung Chul ELSEVIER 2018 APPLIED ENERGY -BARKING THEN OXFORD- Vol.227 No.-

<P><B>Abstract</B></P> <P>In this study, novel perovskite-type Sr<SUB>0.92</SUB>Y<SUB>0</SUB>.<SUB>08</SUB>TiO<SUB>3</SUB>-based catalysts were investigated for hydrogen production by the dry reforming of biogas (comprising CH<SUB>4</SUB> and CO<SUB>2</SUB>). Ni-doped Sr<SUB>0.92</SUB>Y<SUB>0</SUB>.<SUB>08</SUB>TiO<SUB>3</SUB> catalysts with improved catalytic activity were grown using the Pechini method. The prepared catalysts were characterized using X-ray diffraction to check for impurities introduced in the perovskite structure by doping method. The reforming of methane over perovskite-based catalysts has been extensively investigated; however, detailed understanding of the activating catalytic sites under different conditions is still lacking. To understand the details of the activating catalyst mechanism, transmission electron microscopy, temperature-programed reduction, X-ray photoelectron spectroscopic (XPS) analysis were performed under different activating conditions. XPS analysis of 5mol% Ni-doped Sr<SUB>0.92</SUB>Y<SUB>0.08</SUB>TiO<SUB>3</SUB> revealed that the H<SUB>2</SUB>-activated catalyst lost active lattice oxygen sites and Ni sites due to formation of Ni hydroxide. Thus, the H<SUB>2</SUB>-activated catalyst has lower catalytic activity than the N<SUB>2</SUB>-activated one.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The novel Ni-doped Sr<SUB>0.92</SUB>Y<SUB>0.08</SUB>TiO<SUB>3</SUB> was prepared via Pechini Method. </LI> <LI> The novel Ni-doped Sr<SUB>0.92</SUB>Y<SUB>0.08</SUB>TiO<SUB>3</SUB> was activated under N<SUB>2</SUB> or reduction condition. </LI> <LI> The N<SUB>2</SUB>-activated catalyst showed the better activity than the H<SUB>2</SUB>-activated case. </LI> <LI> The 5mol% Ni-doped Sr<SUB>0.92</SUB>Y<SUB>0.08</SUB>TiO<SUB>3</SUB> catalyst showed excellent long-term stability. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

자동차 수리에 있어서의 표준 작업

민병도(Byeong Do Min),이강원(Gang Won Lee),유승동(Seung Dong Yu),한대희(Dae Hee Han),오재건(Jae Geon Oh),이성만(Sung Man Lee),나완용(Wan Yong Na) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

The standard time(ST) is very important part of management efficiency and cost in automobile repair industry. There are many methods of work measurement of automobile repair time in korea. So we have studied differences of work measurements. The main goal of this study is to make people in automobile repair industry understand work measurement.

Evaluation of User Profile Construction Method by Fuzzy Inference

Kim, Byeong-Man,Rho, Sun-Ok,Oh, Sang-Yeop,Lee, Hyun-Ah,Kim, Jong-Wan Korean Institute of Intelligent Systems 2008 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.8 No.3

To construct user profiles automatically, an extraction method for representative keywords from a set of documents is needed. In our previous works, we suggested such a method and showed its usefulness. Here, we apply it to the classification problem and observe how much it contributes to performance improvement. The method can be used as a linear document classifier with few modifications. So, we first evaluate its performance for that case. The method is also applicable to some non-linear classification methods such as GIS (Generalized Instance Set). In GIS algorithm, generalized instances are built from training documents by a generalization function and then the K-NN algorithm is applied to them, where the method can be used as a generalization function. For comparative works, two famous linear classification methods, Rocchio and Widrow-Hoff algorithms, are also used. Experimental results show that our method is better than the others for the case that only positive documents are considered, but not when negative documents are considered together.

광섬유 브래그 격자 센서를 이용한 복합재 구조물의 충격 모니터링 기법 연구

장병욱 ( Byeong Wook Jang ),박상오 ( Sang Oh Park ),이연관 ( Yeon Gwan Lee ),김천곤 ( Chun Gon Kim ),박찬익 ( Chan Yik Park ),이봉완 ( Bong Wan Lee ) 한국복합재료학회 2011 Composites research Vol.24 No.1

복합재 구조물에서 발생하는 저속 충격에 의한 손상은 대부분 복합재의 내부나 충격을 받은 면의 반대 면에서 발생하기 때문에 검출이 쉽지 않아 시간이 지날수록 구조물이 위험에 처할 확률이 높아진다. 하지만 기존의 비파괴검사 방법은 일정한 주기에 따라 수행되기 때문에 즉각적으로 충격 손상을 감지할 수 없다는 단점이 있다. 따라서 최근에는 이러한 단점을 극복하고자 비파괴검사 장비를 구조물 내에 탑재하여 실시간으로 구조물의 건전성을 확인하는 개념인 구조 건전성 모니터링에 관한 연구가 활발히 진행되고 있다. 그 중의 하나인 충격 모니터링 시스템은 운용 중에 발생한 충격 이벤트를 감지하고 그 위치 및 손상 정도에 대한 정보를 제공해 주어야 한다. 이를 위한 첫 번째 단계로 본 연구에서는 복합재 평판 및 복잡한 복합재 시편 구조물에 FBG센서를 부착하여 충격 위치 검출 시험을 수행하였고, 이와 같은 복합재 시편에 대해 충격 파손 시험을 수행하여 손상 발생 유무를 예측하는 시험을 수행하였다. 저속 충격에 의해 발생하는 음향 파는 ㈜파이버프로에서 개발한 고속 FBG interrogator를 사용하여 4개의 다중화된 FBG 센서로부터 동시에 취득하였고, 신경회로망을 이용한 학습을 거쳐 충격 발생 위치를 검출하였다. 또한 충격 파손 시험으로부터 취득한 음향 파의 웨이블릿 변환을 통해 충격 손상의 발생 유무 예측 가능성을 확인하였다. Low-velocity impact can cause various damages which are mostly hidden inside the laminates or occur in the opposite side. Thus, these damages cannot be easily detected by visual inspection or conventional NDT systems. And if they occurred between the scheduled NDT periods, the possibilities of extensive damages or structural failure can be higher. Due to these reasons, the built-in NDT systems such as real-time impact monitoring system are required in the near future. In this paper, we studied the impact monitoring system consist of impact location detection and damage assessment techniques for composite flat and stiffened panel. In order to acquire the impact-induced acoustic signals, four multiplexed FBG sensors and high-speed FBG interrogator were used. And for development of the impact and damage occurrence detections, the neural networks and wavelet transforms were adopted. Finally, these algorithms were embodied using MATLAB and LabVIEW software for the user-friendly interface.