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임민규,박재용,황승민,오영규,박재용,한석영 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-
The objective of this work is to integrate reliability analysis into topology optimization problems. The reliability index determines design domain and uncertainty value. The elemental sensitivity numbers are calculated from finite element analysis and then converted to the nodal sensitivity numbers in the design domain. A mesh-independency filter using nodal variables is introduced to determine the addition of elements and eliminate unnecessary structural details below a certain length scale in the design. To further enhance the convergence of the optimization process, the accuracy of elemental sensitivity numbers is improved by its historical information. Application of the RBTO model gives a different topology relative to DTO. It is found that the RBTO model yields more reliable optimal topologies than those produced by DTO.
오영규,박재용,황승민,임민규,박재용,한석영 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-
This paper presents a reliability-based shape optimization (RBSO) using the evolutionary structural optimization (ESO). An actual design involves uncertain conditions such as material property, operational load and dimensional variation. The deterministic optimization (DO) is obtained without considering uncertainties related to uncertainty parameters. However, the RBSO can consider the uncertainty variables because it has the probabilistic constraints. In order to determine whether the probabilistic constraint is satisfied or not, simulation techniques and approximation methods are developed. In this paper, the reliability-based shape design optimization method is proposed by utilizing the reliability index approach (RIA), performance measure approach (PMA), single-loop single-vector (SLSV), adaptive-loop (AOL) are adopted to evaluate the probabilistic constraint. In order to apply the ESO method to the RBSO, a sensitivity number is defined as the change in the displacement. Numerical examples are presented to compare the DO with the RBSO. The results of design example show that the RBSO model more reliable than deterministic shape optimization.
황승민,박재용,임민규,오영규,한석영 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-
This paper presents a reliability-based topology optimization (RBTO) using bi-directional evolutionary structural optimization (BESO). Topology optimization is formulated as volume minimization problem with probabilistic displacement constraint. Young's modulus, external load and thickness are considered as uncertain variables. In order to compute reliability index, four methods, i.e., RIA, PMA, SLSV and ADL(adaptive-loop), are used. Reliability-based topology optimization design process is conducted to obtain optimal topology satisfying displacement and reliability index constraints with the above four methods, and then each result is compared with respect to numerical stability and computing time.
임신 제 일삼분기와 제 이삼분기 초음파의 태아기형 진단의 유용성에 대한 고찰
최승도,최규연,이정재,정성윤,이임순,이권해 순천향의학연구소 2003 Journal of Soonchunhyang Medical Science Vol.9 No.2
Objective: Ultrasonographic screening between 9 and 13 weeks for fetal structural abnormalities using transvaginal sonography in unselected population. Visualization of detailed fetal anatomy in the first trimester has improved as a result of technological progress in ultrasound machines and the introduction of transvaginal sonography(TVS). Our study aims to evaluate the accuracy of TVS as a screening tool for detecting fetal malformations in a nonselected population of pregnant women. For this purpose we compared the results obtained by using second trimesster TA scanning with those obtained using TVS at 9-14 weeks' gestation. Methods: From March 2001 to February 2003, 620 unselected consecutive pregnant women were recruited at their initial visit at Soonchunhyang university hospital, department of obstetrics and gynecology and offered a TVS scan at the average gestational age of 9-13 weeks in addition to the TA screening usually performed between 22-26 weeks. To fulfill the technical requirements of a screening test, ultrasonographic examinations were performed by skillful operators with different degrees of experienced using adequate instruments Aloka SSD 5500 (Aloka Co. Ltd., Tokyo, Japan) provided with either a 3.5-5MHz TA probe or a 5-7.5MHZ TV probe) in a fixed scanning time of maximum 30 min, generally considered sufficient for a complete fetal anatomic survey. Results: During the study period we found in our unselected population an overall prevalence of target abnormalities of 2.2%(24 malformed fetuses out of 600 screened). In the fetuses examined by TVS, 16 abnormalities were detected whereas 8 were not; of these, 6 were detected at transabdominal rescreening at 22-26 weeks and the remaining 2 were observed after birth. A nuchal region abnormality was the most frequent type of malformation detected in the early scan, including six cases of nuchal edema, two cases of cystic hygroma associated with hygroma associated with hydrops, three cases of hydronephrosis, one case of fetal neck teratoma, one case of cleft lip. Conclusion: This study has demonstrated the potential of screening a low risk population for fetal abnormalities at 9-13 weeks of gestation using transvaginal sonography and rescreened via transabdominal sonography at 22-26 weeks. Larger studies are required to establish the clinical value of the first trimester scan.
김상호,이수영,윤임중,이승한,조규상,김영제 카톨릭대학산업의학센타 산업의학연구소 1972 韓國의 産業醫學 Vol.11 No.3
Among the pneumoconiosis, the silicosis is an occupational lung disease, ordinally due to prolonged inhalation of air containing free silicon dioxide. We had chance to perform autopsy of three cases of silicotuberculosis. Both lungs with hard and contracted appearance, were showed massive fibrous adhesion to pleura and also revealed gritty appearance on cut sectioning, and the cut surfaces were shown dark greenish to black pigmentation. Characteristically, many dense black or grey colored silicotic nodules measuring upto 1-4 mm in diameter, with anthracotic pigments distributed throughout both lung parenchyma especially along the peribronchial regions in all three cases, commonly. Microscopically, the nodules were noted as the mass of concentrically laminated dense fibrotic tissue. In addition to those findings, the pulmonary parenchymas were replaced by wide areas of fibrosis and also accompanied with exudative and productive form of tuberculosis (common in all three cases), bronchopneumonia (except case-1) and also compensating emphysema, atelectatic lesions. At the peripheral areas of the silicotic nodules, focal accumulation of the plasma cells, lymphocytes and many foci of endarteritis were shown in three cases, commonly. The silica was confirmed by polarizing microscopy as birefringent, white colored crystals.
Im, Eun Ju,Kim, Su Jung,Hong, Seung Bok,Park, Jin-Kyu,Rhee, Man Hee Hindawi Publishing Corporation 2016 Evidence-based Complementary and Alternative Medic Vol.2016 No.-
<P>Bee venom has long been used as a traditional folk medicine in Korea. It has been reportedly used for the treatment of arthritis, cancer, and inflammation. Although its anti-inflammatory activity in lipopolysaccharide- (LPS-) stimulated inflammatory cells has been reported, the exact mechanism of its anti-inflammatory action has not been fully elucidated. Therefore, the aim of this study was to investigate the anti-inflammatory mechanism of bee venom in BV2 microglial cells. We first investigated whether NO production in LPS-activated BV2 cells was inhibited by bee venom, and further iNOS mRNA and protein expressions were determined. The mRNA and protein levels of proinflammatory cytokines were examined using semiquantitative RT-PCR and immunoblotting, respectively. Moreover, modulation of the transcription factor NF-<I>κ</I>B by bee venom was also investigated using a luciferase assay. LPS-induced NO production in BV2 microglial cells was significantly inhibited in a concentration-dependent manner upon pretreatment with bee venom. Bee venom markedly reduced the mRNA expression of COX-2, TNF-<I>α</I>, IL-1<I>β</I>, and IL-6 and suppressed LPS-induced activation of MyD88 and IRAK1 and phosphorylation of TAK1. Moreover, NF-<I>κ</I>B translocation by IKK<I>α</I>/<I>β</I> phosphorylation and subsequent I<I>κ</I>B-<I>α</I> degradation were also attenuated. Thus, collectively, these results indicate that bee venom exerts its anti-inflammatory activity via the IRAK1/TAK1/NF-<I>κ</I>B signaling pathway.</P>