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Dynamic Response Analyses of Fixed Type Substructures for 2.5MW Class Offshore Wind Turbine

  • Song, Chang Yong;Yoo, Jaehoon
    • Journal of Advanced Research in Ocean Engineering
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    • v.3 no.1
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    • pp.15-24
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    • 2017
  • This paper explores a series of numerical simulations of dynamic responses of multi-piles (dolphin) type substructures for 2.5MW class offshore wind turbine. Firstly computational fluid dynamics (CFD) simulation was performed to evaluate wave loads on the dolphin type substructures with the design wave condition for the west-south region of Korea. Numerical wave tank (NWT) based on CFD was adopted to generate numerically a progressive regular wave using a virtual piston type wave maker. It was found that the water-piercing area of piles of the substructure is a key parameter determining the wave load exerted in horizontal direction. In the next the dynamic structural responses of substructure members under the wave load were calculated using finite element analysis (FEA). In the FEA approach, the dynamic structural responses were able to be calculated including a deformable body effect of substructure members when wave load on each member was determined by Morison's formula. The paper numerically identifies dynamic response characteristics of dolphin type substructures for 2.5MW class offshore wind turbine.

Characteristics of Electric-Power Use in Residential Building by Family Composition and Their Income Level (거주자 구성유형 및 소득수준에 따른 주거용 건물 내 전력소비성향)

  • Seo, Hyun-Cheol;Hong, Won-Hwa;Nam, Gyeong-Mok
    • Journal of the Korean housing association
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    • v.23 no.6
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    • pp.31-38
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    • 2012
  • In this paper, we draws tendency of the electricity consumption in residential buildings according to inhabitants Composition types and the level of incomes. it is necessary to reduce energy cost and keep energy security through the electricity demand forecasting and management technology. Progressive social change such as increases of single household, the aging of society, increases in the income level will replace the existing residential electricity demand pattern. However, Only with conventional methods that using only the energy consumption per-unit area are based on Energy final consumption data can not respond to those social and environmental change. To develop electricity demand estimation model that can cope flexibly to changes in the social and environmental, In this paper researches propensity of electricity consumption according to the type of residents configuration, the level of income. First, we typed form of inhabitants in residential that existed in Korea. after that we calculated hourly electricity consumption for each type through National Time-Use Survey performed at the National Statistical Office with considering overlapping behavior. Household appliances and retention standards according to income level is also considered.

Associated Factors of Clinical sign in Herniated Lumbar Intervertebral Disc (요추간판탈출증의 임상증상에 관련요인)

  • Kang, Jeom-Deok
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.16 no.2
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    • pp.88-92
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    • 2010
  • Purpose: This study was undertaken to evaluate the effect analysis of clinical sing in 40 patients with lumbar intervertebral disc. Methods: All patients were assessed by the low back pain protocol which was composed of symptom, clinical sing before and after the treatment. The effect of clinical sing was analyzed by age, occupation, duration of symptom. Results: Occupation by clinical sing of after the treatment was desking job s from 3.6 to 5.2 scores(p<0.05). Duration of symptoms by clinical sing of after the treatment was over 4 months from 3.8 to 5.5 scores(p<0.05). Clinical sing of after the treatment was straight leg raising test from 1.275 to 1.850 scores, sensory disturbances from 1.425 to 2.575 scores, manual muscle testing from 1.525 to 4.625 scores. Conclusion: Herniated disks are most common in middle age, especially between 35 and 45, due to aging-related degeneration of the disks. Significant or increasing pain, numbness or weakness spreading to one or both legs. Progressive loss of sensation in areas that would touch a saddle (inner thighs, back of legs and area around the rectum).

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Analytical Approach of Sliding Installation Method with Spar Structure

  • Lee, Jong-Hyun
    • Journal of Navigation and Port Research
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    • v.35 no.7
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    • pp.575-580
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    • 2011
  • It is important to understand the trajectory of structure in launching process because of the short time of launching process may result in unexpected accidents or damage to structures. The high risk of structural failure is not avoidable without the fully comprehension of changing forces in launching procedure. The commercial software can evaluate the motion of launching event in calm water condition but there is the limitation of research application because of the programmed commercial software. The launching process of the spar hull is suggested with stage concept that is divided into 10 stages in time domain. A force equilibrium diagram is derived for each stage where the changes of force vector and motion characteristics take place. In particular, the effects of changes in buoyancy and drag force due to the progressive submergence of the spar hull are taken into account by means of a touch length concept. The results contained in this paper provide the valuable information of the trajectory motion evaluation with suggested methods in spar launching process with sliding barge. Furthermore, the presented stage concept and touch length concept will provide basic knowledge for understanding launching process and help to develop further research area for launching analysis.

A Case of Localized Subaortic Stenosis Associated with Aortic Regurgitation (대동맥판폐쇄부전을 동반한 국소성)

  • 김삼현;서필원
    • Journal of Chest Surgery
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    • v.29 no.7
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    • pp.780-784
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    • 1996
  • The localized form of subaortic stenosis shows a spectrum of pathological lesions varing from dis- crete membrane to a thickened flbromuscular collar. Aortic valve is commonly involved late in the pro- cess resulting in regurgitation. Because of the likelihood o the progressive obstruction and aortic regurgitation, early elective oper- ation should be considered for the patient with subaortic stenosis. We experienced a case of localized fibromuscular subaortic stenosis associated with aortic regurgi- tation. Excision of the fibromuscular ridge and septal myectomy-myotomy relieved the subaortic seen- osis. Regurgitant aortic valve was repaired by peeling away the Hbrotic tissue on the cusps and subcommissural annuloplasty at the each commissural area. On postoperative echocardiographic examination, the systolic pressure gradient between left ventricle and aorta decreased markedly and the aortic regurgitation was not detected at all.

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Increase of diesel car raises health risk in spite of recent development in engine technology

  • Leem, Jong Han;Jang, Young-Kee
    • Environmental Analysis Health and Toxicology
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    • v.29
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    • pp.9.1-9.3
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    • 2014
  • Diesel exhaust particles (DEP) contain elemental carbon, organic compounds including Polyaromatic hydrocarbons (PAHs), metals, and other trace compounds. Diesel exhaust is complex mixture of thousands of chemicals. Over forty air contaminants are recognized as toxicants, such as carcinogens. Most diesel exhaust particles have aerodynamic diameters falling within a range of 0.1 to $0.25{\mu}m$. DEP was classified as a definite human carcinogen (group 1) by the International Agency for Research on Cancer at 2012 based on recently sufficient epidemiological evidence for lung cancer. Significant decreases in DEP and other diesel exhaust constituents will not be evident immediately, and outworn diesel car having longer mileage still threatens health of people in spite of recent remarkable development in diesel engine technology. Policy change in South Korea, such as introduction of diesel taxi, may raise health risk of air pollution in metropolitan area with these limitations of diesel engine. To protect people against DEP in South Korea, progressive strategies are needed, including disallowance of diesel taxi, more strict regulation of diesel engine emission, obligatory diesel particulate filter attachment in outworn diesel car, and close monitoring about health effects of DEP.

Glioblastoma Misdiagnosed as Brain Abscess after Surgical Evacuation of Spontaneous Basal Ganglia Hemorrhage (기저핵부 뇌실질내 출혈에 대한 수술후 뇌농양으로 오인한 다형성 교아세포종)

  • Cheong, Jin Hwan;Kim, Jae Min;Bak, Koang Hum;Park, Yong Wook;Kim, Choong Hyun;Oh, Suck Jun
    • Journal of Korean Neurosurgical Society
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    • v.30 no.3
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    • pp.384-388
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    • 2001
  • A 51-year-old woman presented with sudden severe headache, vomiting, and right hemiparesis at first admission. Computed tomography(CT) scans revealed an hemorrhagic density at left basal ganglia. Preoperative cerebral angiography showed no vascular lesion. Under the diagnosis of hypertensive intracerebral hemorrhage(ICH), total extirpation of hematoma was done. The postoperative neurological condition improved gradually and discharged without any neurological sequelae. Two months later, she revisited with headache, vomiting and progressive right hemiparesis. CT scans at second admission showed an irregular rim enhanced mass with central low density with surrounding edema at the initial bleeding area. Repeated craniotomy was performed and the mass was partially removed. The histopathological diagnosis of the specimen was confirmed as glioblastoma. The authors report a glioblastoma, which occurred at initial ICH site and regarded as a brain abscess with literature review.

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Atypical Intramuscular Myxoma of the Lumbosacral Paraspinal Muscle : The First Case Report in Asian

  • Choi, Doo Yong;Kim, Jong Tae;Kim, Jiyoung;Lee, Ho Jin
    • Journal of Korean Neurosurgical Society
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    • v.58 no.6
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    • pp.566-570
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    • 2015
  • Intramuscular myxoma (IM) is a benign neoplasm of mesenchymal origin. We report a rare case of IM which was located in the lumbosacral paraspinal muscles. A 62-year-old female patient presented with progressive low back pain for 2 months, and the radiologic findings showed a large mass ($4.0{\times}3.5{\times}6.5cm$) in the right lumbosacral paraspinal area. Total resection of the tumor was performed and the symptom was nearly resolved after surgery. Although the immuno-histopathological analysis was consistent with IM, there were some different findings from typical pathological characteristics of IM in this case. Firstly, the symptomatic change of the mass took relatively short time (less than 3 months), and this change was accompanied by partial calcification inside the mass. Moreover, iatrogenic interruption of paravertebral muscle by the other previous operation might be the promoting factor of the fibrous dysplasia, which can explain the pathogenesis of IM. To our knowledge, this is the eighth case of the lumbar paraspinal myxoma reported in the literatures and the first case in Asian population.

Analysis of FRP-Confined Concrete According to Lateral Strain History (횡변형률 이력에 근거한 FRP-구속 콘크리트의 해석)

  • Cho, Soon-Ho
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.201-204
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    • 2008
  • The proposed method, capable of predicting various stress-strain responses in axially loaded concrete confined with FRP (Fiber Reinforced Polymers) composites in a rational manner, is based on the fact that the volumetric expansion due to progressive microcracking in mechanically loaded concrete is an important measure of the extent of damage in the material microstructure. The elastic modulus expressed as a function of area strain and concrete porosity, the energy-balance equation relating the dilating concrete to the confining device interactively, the varying confining pressure, and an incremental calculation algorithm are included in the solution procedure. This procedure enables the evaluation of lateral strains consecutively according to the related mechanical model and the energy-balance equation, rather than using an empirically derived equation for Poisson's ratio or dilation rate as in other analytical methods.

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A Study on the Content Framework of Algorithm Education in Primary and Middle Schools (초등학교와 중학교에서의 정보과학 교과를 위한 알고리즘 교육내용체계에 관한 연구)

  • Jeong, Young-Sik
    • Journal of The Korean Association of Information Education
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    • v.18 no.2
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    • pp.275-284
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    • 2014
  • In this study, we analyzed algorithm curriculum in Korea, the United Kingdom, the United States, India, and Estonia. In order to teach 1st - 9th grade students computer algorithm, we suggested the algorithm framework based on the spiral curriculum, which is repeatable and progressive. The framework is divided into 4 areas, which includes understanding, expressing, evaluating, and using algorithms in daily life. Each area has 4 levels which are based on the students grade. We have to offer lectures for about computer OS to student teachers at the National Universities of Education; to develop textbooks and materials about algorithm; and to establish Information Science as a part of the primary school curriculum.