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CFD/Kirchhoff Integral Method for the Prediction of the Air-Pumping Noise by a Car Tyre (CFD/Kirchhoff 적분 방법을 이용한 자동차 타이어의 Air-Pumping 소음 예측)

  • Kim, Sung-Tae;Lee, Soo-Gab
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.11a
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    • pp.916-919
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    • 2004
  • The monopole theory has long been used to model air-pumped effect from the elastic cavities in car tire. This approach models the change of an air as a piston moving backward and forward on a spring and equates local air movements exactly with the volume changes of the system. Thus, the monopole theory has a restricted domain of applicability due to the usual assumption of a small amplitude acoustic wave equation and acoustic monopole theory. This paper describes an approach to predict the air-pumping noise of a car ave with CFD/Kirchhoff integral method. The type groove is simply modeled as piston-cavity-sliding door geometry and with the aid of CFD technique flow properties in the groove of rolling car tyre are acquired. And these unsteady flow data are used as a air-pumping source in the next Cm calculation of full tyre-road geometry. Acoustic far field is predicted from Kirchhoff integral method by using unsteady flow data in space and time, which is provided by the CFD calculation of full tyre-road domain. This approach can cover the non-linearity of acoustic monopole theory with the aid of using Non-linear governing equation in CFD calculation. The method proposed in this paper is applied to the prediction of air-pumping noise of modeled car tyre and the predicted results are qualitatively compared with the experimental data.

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Estimation and Feature of Greenhouse Gas Emission in Building Sector by National Energy Statistic (국가 에너지통계에 따른 건물부문 온실가스 배출량 추계 및 특성)

  • Jeong, Young-Sun;Kim, Tae-Hyoung
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.35 no.7
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    • pp.187-195
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    • 2019
  • In December 2015, The Paris Agreement was adopted to undertake ambitious efforts to combat climate change. Korean government announced its goal of reducing the country's greenhouse gas emissions by up to 37% below business as usual projections by 2030 in 2015. The purpose of this study was to set up the calculation methodology of GHG emission($CO_{2e}$) in building sector and to estimate the annual GHG emission in building sector based on national energy consumption statistic. The GHG emission from buildings is about 135.8 million ton $CO_{2e}$ as of 2015, taking up about 19.6% of Korea's entire emission and is about 144.7 million ton $CO_{2e}$ in 2017. The GHG emission of building sector is increasing at annual rate of 2.0% from 2001 to 2017. The GHG emission from electricity consumption in buildings is 91.8 million ton $CO_{2e}$ in 2017, is the highest $CO_2$ emission by energy source. The results show that the intensity of GHG emission of residential building sector is $40.6kg-CO_{2e}/m^2{\cdot}yr$ and that of commercial building sector is $68.4kg-CO_{2e}/m^2{\cdot}yr$.

Greenhouse Gas Reduction Scenario from LEAP Model Application to a University Campus-For Hanyang University Ansan Campus (LEAP 모델 적용을 통한 대학단위 온실가스 감축안 도출 - 한양대학교 안산캠퍼스 대상으로)

  • Park, Hyo-Jeong;Jung, Hye-Jin;Yi, Seung-Muk;Park, Jae-Woo
    • Journal of Korean Society of Environmental Engineers
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    • v.34 no.4
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    • pp.280-287
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    • 2012
  • The sources of greenhouse gases (GHG) at Hanyang University Ansan campus, including direct sources, indirect sources, and others, were investigated in order to establish the GHG inventory. Emission of GHG was calculated with the energy use from each source from 2007 and 2009. The indirect emission (56.7%) due to the electricity significantly contributed to total GHG emission. The scenario for the GHG reduction was designed for both campus administration and members. The reduction potential of GHG was simulated from 2007 to 2020 using Long-range Energy Alternatives Planning (LEAP) model. In case of GHG reduction scenario by campus administration, the GHG can be reduced by 63.34 ton $CO_{2eq}/yr$ for stationary combustion in the direct source, by 221.1 ton $CO_{2eq}/yr$ for mobile combustion in the direct source, and by 4,637.34 ton $CO_{2eq}/yr$ for lighting in the indirect source, compared to 2020 Business As Usual (BAU). In case of GHG reduction action scenario by campus members, the reduction potential of GHG was 1293.76 ton $CO_{2eq}/yr$. Overall, the total GHG emissions in 2020 by the both scenarios can be decreased by 24% compared to 2020 BAU.

Association of Total Sugar Intakes and Metabolic Syndrome from Korean National Health and Nutrition Examination Survey 2001-2002 (한국 성인의 총당류 섭취와 대사증후군과의 관계 -2001년과 2002년도 국민건강영양조사자료를 이용하여-)

  • Chung, Chin-Eun
    • Journal of Nutrition and Health
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    • v.40 no.sup
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    • pp.29-38
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    • 2007
  • The purpose of this study was to establish an association between the percent of energy from total sugar and disease prevalence of obesity, hypertension, dyslipidemia, insulin resistance, and metabolic syndrome with the context of the current population dietary practice in Korea. The Korean National Health and Nutrition Survey, 2001 and 2002 dataset were used as the source of data for this research. Usual nutritional intakes for over 20 years old people were calculated from the two non-consecutive dietary intake data from KNHANES 2001 and 2002 dataset. SAS and SUDAAN were used for statistical analyses. Sample weighted means, standard errors, and population percentages were calculated, and multiple logistic regression model with adjustment for covariates were used to determine the odds ratios(ORs) and 95% confidence intervals. Subjects were categorized as 3 ways and compared the LS means and ORs for heath factors. First, subjects excluding pregnant women, were categorized according to percent of energy from the usual total sugar intakes as ${\leq}10%$, 11-15%, 16-20%, 21-25%, >25%. Risk of LDL cholesterol showed a tendency to increase in the '>25%' group compared to the '<10%' group. The risks of the other health effects did not show any significant differences. Second, the subjects were categorized considering both Acceptable Macronutrient Distribution Range(AMDR) from carbohydrate and %Energy from total sugar as 'CHO<55% & Total sugar ${\leq}10%$', 'CHO 55-70% & Total sugar 11-25%', and '$CHO{\geq}70%$ & Total sugar ${\geq}25%$'. The risk of obesity tended to increase in the '$CHO{\geq}70%$ & Total sugar ${\geq}25%$' group compared to the 'CHO<55% & Total sugar ${\leq}10%$'. Third, the subjects were categorized as 'CHO<55% & Total sugar ${\leq}10%$', 'CHO 55-70% & Total sugar 11-20%', and '$CHO{\geq}70%$ & Total sugar ${\geq}20%$'. The risk of obesity also tended to increase in the '$CHO{\geq}70%$ & Total sugar ${\geq}20%$' group compared to the 'CHO<55% & Total sugar ${\geq}20%$' group. In conclusion, risk of LDL cholesterol showed a tendency to increase in the over 25% total sugar intake group, and the risk of obesity tended to increase in the 20-25% total sugar intake and high carbohydrate intake group. The risks of hypertension, hyperlipidemia, insulin resistance, and metabolic syndrome were not associated with total sugar intakes. More research to elucidate the association for Korean between the intakes of total sugar, added sugar, glucose, fructose, and sweeteners and diseases prevalences shoud be excuted in the future.

Influence of Nitrogen, Phosphorous, Potassium and Sucrose on the Shoot and Bulb Growth of Allium victorialis var. platyphyllum (산마늘의 신초와 구근생장에 미치는 질소, 인, 칼륨 및 당의 영향)

  • Jeong, Mi-Jin;Song, Hyun-Jin;Sim, Seon-Jeong;Doh, Eun-Soo;Chang, Jun-Pok;Yang, Jae-Kyung;Yun, Chung-Weon;Lee, Cheol-Ho;Karigar, Chandrakant. S.;Choi, Myung-Suk
    • Korean Journal of Medicinal Crop Science
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    • v.20 no.2
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    • pp.101-107
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    • 2012
  • Effects of nitrogen (N), phosphorous (P) and potassium (K) on the shoot and bulb growth of wild garlic ($Allium$ $victorialis$ var. $platyphyllum$) were studied by adopting $in$ $vitro$ culture. These macronutrients influenced the growth of both the shoot and bulb of garlic depending upon their application doses. A minimum of 3% potassium nitrate ($KNO_3$) as a source of nitrogen was found to be critical for shoot elongation while higher concentrations were inhibitory. Garlic bulb growth was profuse on the usual $KNO_3$ strength and sucrose (7%), followed by $KNO_3$ (9.4 mM) supplement. On providing 41.22 mM ammonium nitrate ($NH_4NO_3$) as nitrogen source highest shoot growth was observed while 82.45 mM $NH_4NO_3$ as a source of nitrogen supported high bulb growth. With regard to potassium a good shoot growth was observed in medium that contained 0.31 mM $KH_2PO_4$ and 3% sucrose, while bulb growth was high on 2.5 mM $KH_2PO_4$ and 7% sucrose. These experiments may thus direct the development of excellent growth conditions for the commercial production of edible wild garlic.

A study on Architectural Characteristics of Exhibited Houses at the Choseon Exhibition(1929) - Focused on the Relationship of Exhibited Houses in Japan - (조선박람회 출품주택의 건축계획 특성에 관한 연구 - 일본의 박람회 출품주택과 관계를 중심으로 -)

  • Chung, Soon-Young
    • Journal of architectural history
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    • v.17 no.2
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    • pp.7-25
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    • 2008
  • This study aims to clarify the architectural characteristics of three houses of Choseon Exhibition. Exposition/exhibitions were thought to be a model for the world. It shows the real status of the development, and thinking with visions at that times; therefore, exhibited house models would be a good source for what to be considered for the ideal houses of that times. Through the study, we could find out as belows. 1. The houses exhibited conserved the sitting-on-floor living style, otherwise the most proposals for house improvement suggested a chair-and-table style because of its hygienic quality and integration of the life at home and at work(school, too). 2. The spacial scheme for-family prior over for-guest was emphasized, but models at the exhibition were structured with Japanese traditional spacial program, such as Jashiki(座敷), Kyakunoma(客の間) or Tsuginoma(次の間), which were all Tatami-floored. 3. Through this exhibition, it is clarified that the architectural society in colonial Korea also tried to improve the modern housings, not only direct reception of the developed proposals. These houses was planned with the acceptance of the locality, such like Ondol, a floor heating facility which the Japanese engineer improve the efficiency. 4. Also these exhibited houses became a start to recognize a house as a product, and spurred on commercialization. As the result, we could find out that these exhibited houses accepted the modern housing proposals selectively, and that even if the exhibitions shows the advance in usual these houses were planned with the very conservative notions.

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The Treatment of Uterine Cervical Cancer Using High Dose Rate Co-60 Sources (고선량율(高線量率) 강내조사법(腔內照射法)을 이용(利用)한 자궁경암(子宮頸癌) 방사선(放射線) 치료(治療))

  • Kim, G.E.;Suh, C.O.;Lee, D.H.;Park, C.Y.
    • Radiation Oncology Journal
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    • v.1 no.1
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    • pp.95-102
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    • 1983
  • The radical treatment of uterine cervical cancer by interacavitary radium or cesium, in combination with teletherapy are well known. Although the result of such treatment should not give rise to complacency, problem of radiation exposure to medical staff had not been resolved. Fortunately, many attempts have been made to reduce this hazard, most of which take the form of afterloading applicators with a suitably shielded radioisotope. In order to avoid hazardous radiation exposure to staffs concerned with brachytherapy, RALS using high intensity source of Co-60, have been employed at Yonsei Cancer Center since May, 1979. It allows rectal and bladder doses to be kept low, while maintaining a satifactory usual dose distribution of the other type of applicators, and the short treatment time allow four or five patients to be treated per hour. It also removes much patient's discomfort and the difficulties of nursing these patients. Since the first introduction in Korea, over seven hundred cases with various stage of uterine cervical cancer have been treated on a radical basis at this center last 4 years. These authors have strongly attracted attention to the results in terms of local control rate, survival s and morbidity compared with those of conventional low dose rate radiotherapy. Retrospective interim analysis of data was preliminarily accomplished through the labored follow-up study of 340 cases treated during initial 2 years and the radiobiologic standpoint of high dose rate intracavitary irradiation will be discussed.

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A Study on the Information Seeking and Utilization of College Students at the Time of Their Political Decision Making During Elections (정치적 의사결정이 필요한 선거기간동안 대학생의 정보 탐색 및 활용에 관한 연구)

  • Lee, Jeong-Mee
    • Journal of the Korean BIBLIA Society for library and Information Science
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    • v.28 no.1
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    • pp.293-315
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    • 2017
  • This study investigated how college students seek and use information sources at the time of their decision making (especially during elections on this study). More than 360 students in 12 colleges located in Seoul were randomly selected and participated in this study. The survey asked them what kind of information sources they use at the time of their decision making as well as when they use information as usual. Several criteria for information evaluation were adopted to analyze information attributes and information seeking behavior of the population. Compare to the previous studies, Internet resources are more used than ever, information credibility and authority affected more to the population's political decision making. Additional examinations were executed to see deeper story of their information seeking at the end.

A Study on the Fine Structure of Clonorchis sinensis, a Liver Fluke V. The Mature Spermatozoa (간흡충의 미세구조에 관한 연구 V. 정자의 미세구조)

  • 정계환;임한종
    • Parasites, Hosts and Diseases
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    • v.22 no.1
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    • pp.30-36
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    • 1984
  • An ultrastructural study on the mature spermatoBoa oi Cloptorchis sineitsis was carried out. For this study, the liver cukes were collected from the livers of rabbits and rats artificially infected with the metacercariae obtained from the fresh water fish, Pseudorasbora parve. Six-month old worms were used. The collected liver fiukes were washed with 0.85% saline solution and then immediately moved to cold 2% glutaraldehyde buffered with 0.1M Millonig's phosphate buffier (pH 7.4) . The materials were dissected into appropriate pieces in the fixative about 30 minutes after beginning of the fixation. Two hours later the materials containing the seminal receptacle were rinsed several times with the buffier and were secondarily fixed with cold, bugeyed 1% osmium tetroxide(OsO4) for 2 hours. The fully mixed tissue blocks Ivere dehydrated in a series of graded concentrations of acetone and were embedded in Epon 812 mixture. Thin sections obtained from LKB-5 ultramicrotome were stained with uranyl acetate and Reynold's lead citrate. Observations of the sections were carried out with JEM-100CX II electron microscope, In general, the mature sperm was long thread-like form with a sickle-shaped head. According to the longitudinal sectioned view of the sperm tail, the nucleus seemed to be spirally coiled and run a little far along the tail. The acrosome was not observed. The cytoplasm of the tail was biflagellated as usual in trematodes. Unlike other platyhelminth spermatozoa, the sperm tail of Clenorchis sinensis showed the ${\ulcorner}9+2{\lrcorner}$ in the microtubular arrangement. The mitochondria with poorly developed cristae were observed throughout the middle piece. The middle piece of the tail showed dull ladder or triangular shapes with the two flagella at the bottom. But, the principal piece of the tail was slightly flattened cylindrical shape with two aagella within the cytoplasm. The end piece was uniflagellated. It was not clearly identised whether the end piece was subdivided into two by aagellum or the lengths of the two aagella were different. The glycogen granules were rich in the cytoplasm throughout the lenght of the spermatozoa. These granules might be the energy source for the movement of the spermatosoa.

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Performance Analysis of Asynchronous 2.5 Gbps / 622Mbps Optical Subscriber Network with Manchester coded Downstream and NRZ upstream re-modulation (맨체스터 부호로 코딩된 하향신호의 재변조를 이용한 비동기 2.5 Gbps / 622 Mbps 광가입자 망의 성능 분석)

  • Park, Sang-Jo;Kim, Bong-Kyu
    • Korean Journal of Optics and Photonics
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    • v.20 no.3
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    • pp.143-147
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    • 2009
  • We propose an asymmetrical 2.5 Gbps / 622 Mbps bidirectional optical subscriber network with Manchester coded downstream and NRZ (Non-Return-to-Zero) upstream remodulation. The proposed system has important characteristics in the optical network unit (ONU): it does not require a light source or the usual control circuits such as wavelength control and output power control, and it is possible to use a synchronization scheme between upstream and downstream data. We theoretically analyze BER(Bit Error Rate) performance of upstream data remodulated with Manchester coded downstream according to the types of NRZ downstream data and perform simulations with MATLAB. The BER performance and the receiver sensitivity have been improved by 3 dB by adjusting threshold levels compared to the conventional receiver. The results have shown the remodulation scheme with Manchester coded downstream could be a useful technology for asynchronous and asymmetric optical subscriber networks with low cost and simple structures.