휴대폰 카메라용 자동초점 구동기의 충격해석

이성민,김봉석,송준호,이수훈,이혜진,이문구,송준엽,이창우 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-

Recently, the robustness against daily impact is important according to portablization and downsizing of mobile electronics. Especially, almost parts of cellular phone should undergo drop test when they fall 1.5 m above ground. This test simulates the case when cellular phone slips through user's fingers while he is talking on the phone. This paper studies a drop test of auto focusing (AF) actuator for camera module in cellular phone. This component is composed of voice coil motor (VCM) as an actuator and leaf spring as a guide and suspension. The leaf spring's deformation is essential for the test because its permanent distortion disables the focusing, and then, a high quality photograph cannot be obtained. Up to now the drop test has been carried out after fabricating real AF actuator. We propose a dropt test model which simulates the drop test based on finite element analysis. This model makes us enable investigate the stress acting on the clamping and curved parts of leaf spring. Stress over Von Mises criterion lets the spring deformed permanently, and then AF actuator malfunctioned, It helps us to design and modify AF actuator without manufacturing the real product. And also, it saves the time and cost for the development of new products.

Ti-6Al-4V 합금의 동적변형특성과 탄도충격성능 : 1. 초고속 폭발충격 특성 1. Ultra-high-speed Exploding Properties

이유환,이동근,이성학,이종수,최준홍,허선무 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.10

The effects of microstructural morphology on ultra-high-speed exploding properties of Ti-6Al-4V alloy were investigated in this study. Exploding bridge wire (EBW) test was conducted on equiaxed and bimodal microstructures, which were processed by different heat treatments. From the test, moving velocity of free surface vs time profiles were obtained to measure strength at Hugoniot elastic limit (HEL) and spall strength and to subsequently predict ballistic mass efficiency. The EBW results indicated that impact resistance of the bimodal microstructure was better than that of the equiaxed microstructure when the measured strength at HEL and spall strength were considered. It was also learned from the observation of fractured EBW specimens that fracture occurred by the initiation and propagation of long cracks in the equiaxed microstructure, whereas a number of microcracks were formed and connected each other in a zig-zag pattern to reduce the driving force for crack propagation in the bimodal microstructure. Since the EBW test helped experimentally estimate ultra-high-speed deformation and fracture behavior, it could be effectively used for the prediction of ballistic impact performance.

Impedance를 이용한 전도성고분자 센서의 가스감응특성

이경문,유준부,이병수,전희권,이상태,이덕동,허증수 경북대학교 센서기술연구소 2002 센서技術學術大會論文集 Vol.13 No.1

수근관 증후군에서의 무증상성 척골신경병증

문준식,이성수,이지용,한범기,권준범,양현덕,이성익 대한신경과학회 1999 대한신경과학회지 Vol.17 No.2

전도성 고분자 센서 어레이를 이용한 휘발성 유기 화합물 가스 인식

이경문,주병수,유준부,황하룡,이병수,이덕동,변형기,허증수 한국센서학회 2002 센서학회지 Vol.11 No.5

휘발성 유기 화합물 가스(Volatile Organic Compounds)를 인식하고 분석하기 위하여 전도성 고분자 센서어레이를 이용한 시스템을 제작하였다. Polypyrrole와 Polyaniline을 화학중합법으로 센서에 전도성고분자막을 형성하였고 이를 통해 VOC 검지용 센서 어레이를 제작하였다. 센서어레이로부터 측정되는 다차원 데이터는 주성분분석법(PCA)과 RBF(Radial Basis Function Network)을 이용하였다. 제안된 시스템으로 VOCs 가스를 인식하는데 있어서 RBF Network이 PCA방식보다 더욱 효율적인 것으로 판단되었다. We fabricated gas recognition system using conducting polymer sensor array for recognizing and analyzing VOCs(Volatile Organic Compounds) gases. The polypyrrole and polyaniline thin film sensors which were made by chemical polymerization were employed to detect VOCs. The multi-dimensional sensor signals obtained from the sensor array were analyzed using PCA(principal component analysis) technique and RBF(radial basis function) Network. Throughout the experimental trails, we confirmed that RBF Network is effective than PCA technique in identifying VOCs.

혼수상태의 외상환자에서 초음파를 이용한 흉부 및 복부손상의 진단

임경수,이강현,이진웅,이부수,황성오,유수영,강성준 대한응급의학회 1995 대한응급의학회지 Vol.6 No.1

The need for rapid diagnosis and treatment of life-threatening thoracic and intra-abdominal injury result in controversy over the appropriate triage of unconscious blunt trauma patients. To aid in early decisions for these patients, a prospective analysis of 98 patients with glasgow coma scale(GCS) scores≤8 was undertaken. Although intra-thoracic and intra-abdominal injuries were frequently identified based on systolic blood ressure, the use of clinical signs alone resulted in more missed injuries than did using the emergency ultrasonography. In normotensive patients(n=34), intra-thoracic injuries was identified in one patient(2.9%), and intra-abdominal injuries were in 7 patients(20.6%). In shock(systolic blood pressure<90mmHg) Pa-tients(n=64), thoracic injuries and intra-abdominal injuries were diagnosed in 8(12.5%) and 27 patients(42.3%), thoracic and abdominal combined injuries were identified in 11 patients(17.2%). The sensitivity, specificity, and accuracy of emergency ultrasonography were 96.3%, 91.7%, 94.9%. This study suggests that all unconscious trauma patients undergo immediate emergency ultrasonography to prevent missing life-threatening injuries.

소유-지배 괴리도가 경영진단의견서 공시에 미치는 영향

채수준(Chae, Soo-Joon),이아영(Lee, A-Young) 한국경영교육학회 2020 경영교육연구 Vol.35 No.4

[연구목적] 본 연구는 소유지배괴리도가 공시품질에 어떠한 영향을 미치는 지 분석하고자 하였다. 소유지배괴리도는 공정거래위원회가 ‘대규모기업집단 정보공개시스템’을 통해 제공하고 있는 지배주주의 소유권 및 지배권을 사용하여 측정하였으며, 공시품질로는 경영진단의견서(MD&A)를 고려하였다. [연구방법] 본 연구는 소유지배괴리도가 경영진단의견서 공시품질에 미치는 영향을 검증하기 위해서 2010년부터 2013년까지 유가증권시장에 상장된 1,483 기업-연도 표본을 대상으로 선형회귀분석을 실행하였다. [연구결과] 소유지배괴리도와 MD&A 공시품질 간에는 유의한 양(+)의 관련성이 존재하는 것으로 나타났다. 즉, 소유지배괴리도가 큰 기업일수록 MD&A 공시사항을 충실히 기재하고 있음을 확인하였다. 이는 상반된 두개의 해석을 가능하게 한다. 높은 소유지배괴리도로 인한 지배주주의 사익추구 가능성을 은폐하기 위한 수단으로 공시를 적극적으로 활용할 수 있다는 측면과 높은 소유지배괴리도로 인한 기업지배구조에 대한 부정적인 기업이미지를 해소하고 시장과 원활하게 소통하기 위해 공시를 활용할 수 있다는 해석이 가능하다. [연구의 시사점] 본 연구는 소유지배괴리도와 같은 기업의 소유구조가 기업의 공시품질에 영향을 미치는 요소임을 규명한다는 점에서 공헌도가 있다. 본 연구의 실증결과는 괴리도가 큰 기업일수록 MD&A와 같은 재량적 공시를 적극적으로 수행함으로써 소유구조에 따른 대리인 비용 및 정보비대칭을 완화하고자 하고 있음을 보여준다. 아울러, 대규모 기업집단 지정과 같은 규제제도가 기업들에게 스스로를 관리하게 하는 유인이 될 수 있음을 시사한다. [Purpose] The purpose of this study is to analyze how control-ownership wedge affects disclosure quality. We consider Management Discussion and Analysis(MD&A) as a proxy for disclosure quality [Methodology] This study conducted a linear regression analysis for 1,483 firm-year samples listed on the KOSPI market from the period between 2010 to 2013 to verify the effect of the ownership and control wedge on MD&A. [Findings] This paper showed that there is a significant positive (+) relationship between control-ownership wedge and MD&A disclosure quality. The results of this study verified that firms with a greater degree of control-ownership wedge faithfully described MD&A disclosure items. These results can be explained in two opposite directions. One explanation is that managers of firms with a greater degree of control-ownership wedge can actively use the MD&A disclosure as a mean to conceal the pursuit of the interests of the controlling shareholders. The other explanation is that the MD&A disclosure can be used to solve the negative corporate image of the corporate governance structure due to a high degree of control-ownership wedge and to communicate smoothly with the capital market. [Implications] This study has a contribution that the company’s ownership structure, such as the control-ownership wedge, is a factor influencing the disclosure quality of the company. The empirical results of this study show that firms with a greater degree of control-ownership wedge actively disclose the discretionary disclosure such as MD&A to alleviate agency cost and information asymmetries according to the ownership structure.

한국인의 식생활 변화 추이 조사를 통한 영양 개선 방안

이명희,문수재,이민준,김정현 培材大學校 1997 培材論叢 Vol.2 No.-

본 연구에서는 현재까지 진행되어 왔던 국민 영양 조사 보고를 종합하여 한국인의 식생활 행태 변화에 대한 결과를 종적, 횡적으로 분석해 봄으로써 한국인의 영양문제를 파악해 보고자 하였으며, 여기에서 얻어진 결과를 요약하면 다음과 같다. 우리나라 국민 1인 1일당 에너지 섭취는 70년대까지는 증가하다가 그후 서서히 감소하는 경향이었으며 당질 섭취량은 감소하는 반면 지방 섭취량은 80년대 이전부터 조금씩 증가하기 시작하여 80년대 후반기에 이르러 그 변화가 더욱 뚜렷하였다. 곡류로 부터 얻는 열량의 비는 70년대에 82.1%에서 90년대에는 65.8%로 당질 위주의 식사에서 탈피하였다. 단백질 섭취량의 연차적 변화는 동물성 급원에서 얻는 비율이 증가하여 질적 향상을 나타냈다. 무기질중 칼슘의 섭취량은 계속 증가는 하고 있으나 권장량 수준에 미달되고 있으며, 철분의 경우는 섭취량이 꾸준히 증가하여 80년대 전반기에 이미 권장량 이상을 섭취하는 것으로 나타났다. 비타민 A는 변동의 폭이 많아 일관된 변화 양상을 볼 수 없었으며 티아민, 나이아신과 비타민 C는 권장량 이상을 섭취하고 있는 반면 리보플라빈은 연차적으로 우유 섭취의 증가와 함께 증가하여 권장량에 근접하는 섭취 양상을 나타내었다. For the last a few decades, Korea has experienced rapid economic growth, and the lifestyle of Koreans has become more westernized. Specially eating habit and food availability have changed so quickly. The main purpose of this study is to estimate the annual trend of food and nutrient intake, to evaluate the relationship between dietary pattern and the structure of disease and to define the groups that have the risk of nutritional problems. Until mid 1970s total calorie intake was provided by 75% from carbohydrate and less than 10% from fat. While total calorie intake was decreased since 1980, the composition of calorie sources has changed; calorie from fat and protein has increased and that of carbohydrate has decreased. The dietary pattern of the Korean population has rapidly changed with high intake of meat, fish and milk and low intake of cereals. With the change in dietary pattern, it could have been expected to change the major causes of death and morbidity rate.

원전 체크밸브 진단기법 개발을 위한 음향방출기법 및 신경회로망 적용에 관한 연구

이민래,이준현,최상우,김정택,김정수 한국비파괴검사학회 2004 학술대회 논문집 Vol.- No.-

This work performed in support of the International Nuclear Energy Research Initiative(INERI) program, which was to develop and demonstrate advanced sensor and computational technology for on-line monitoring of the condition of components, structures, and systems in advanced and next-generation nuclear power plants(NPPs). The primary objective of this work is to investigate advanced condition monitoring systems based on acoustic emission detection that can provide timely detection of check valve degradation and service aging so that maintenance/replacement could be preformed prior to loss of safety function. The research is focused on the capability of AE technique to provide diagnostic information useful in determining check valve aging and degradation, check valve failures and undesirable operating modes. This work also includes the study to detect failure in check valves using neural networks.

제주도 해안선 주변 부착규조류의 종조성 및 분포

이준백,좌종헌,김일수 제주대학교 해양연구소 1991 해양자원연구소연구보고 Vol.15 No.-

The distribution and species composition of periphytic diatoms around the coast line of Cheju Island have been investigated at four costal stations from April 1991 to June 1991. During the study period, 71 taxa periphytic diatoms are collected, of which are composed of 11 families, 32 genera, 59 species. 12 unidentified species. More than 20% of periphytic diatoms are occupied by the 12 abundant species. Cucconeis scutellum, Cylindrotheca closterium, Licmophora abbreviata are observed in all the coasts and all the attached substratum, and predominated more than 50% so that these species are the most typical dominant species troughout the study period.