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Seismic response and energy dissipation in partially restrained and fully restrained steel frames: An analytical study

  • Reyes-Salazar, Alfredo;Haldar, Achintya
    • Steel and Composite Structures
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    • v.1 no.4
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    • pp.459-480
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    • 2001
  • The damage suffered by steel structures during the Northridge (1994) and Kobe (1995) earthquakes indicates that the fully restrained (FR) connections in steel frames did not behave as expected. Consequently, researchers began studying other possibilities, including making the connections more flexible, to reduce the risk of damage from seismic loading. Recent experimental and analytical investigations pointed out that the seismic response of steel frames with partially restrained (PR) connections might be superior to that of similar frames with FR connections since the energy dissipation at PR connections could be significant. This beneficial effect has not yet been fully quantified analytically. Thus, the dissipation of energy at PR connections needs to be considered in analytical evaluations, in addition to the dissipation of energy due to viscous damping and at plastic hinges (if they form). An algorithm is developed and verified by the authors to estimate the nonlinear time-domain dynamic response of steel frames with PR connections. The verified algorithm is then used to quantify the major sources of energy dissipation and their effect on the overall structural response in terms of the maximum base shear and the maximum top displacement. The results indicate that the dissipation of energy at PR connections is comparable to that dissipated by viscous damping and at plastic hinges. In general, the maximum total base shear significantly increases with an increase in the connection stiffness. On the other hand, the maximum top lateral displacement $U_{max}$ does not always increase as the connection stiffness decreases. Energy dissipation is considerably influenced by the stiffness of a connection, defined in terms of the T ratio, i.e., the ratio of the moment the connection would have to carry according to beam line theory (Disque 1964) and the fixed end moment of the girder. A connection with a T ratio of at least 0.9 is considered to be fully restrained. The energy dissipation behavior may be quite different for a frame with FR connections with a T ratio of 1.0 compared to when the T ratio is 0.9. Thus, for nonlinear seismic analysis, a T ratio of at least 0.9 should not be considered to be an FR connection. The study quantitatively confirms the general observations made in experimental results for frames with PR connections. Proper consideration of the PR connection stiffness and other dynamic properties are essential to predict dynamic behavior, no matter how difficult the analysis procedure becomes. Any simplified approach may need to be calibrated using this type of detailed analytical study.

A Survey of the Effect of Nursing Students on Community Health Knowledge (간호학생 실습이 지역주민의 보건지식 및 태도에 미치는 영향 -연세대학교 간호대학 보건간호학 실습을 중심으로-)

  • 조원정;김의숙;이정숙
    • Journal of Korean Academy of Nursing
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    • v.3 no.2
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    • pp.111-119
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    • 1973
  • The purpose of this study was to determine whether or not the delivery of health services effects the health knowledge of the recipients of that service. 10 was hypothesized that the practical application of theory, though health services rendered by public health nursing students during their field experiences. would have a positive relationship with the quantity and quality of health knowledge of the female population of a given community. In April 1970, ninety five women(between an age 15-49) from Koyang-Gun were interviewed regarding their knowledge and attitudes in four areas of health: maternal health, child health. family planning and tuberculosis prevention. After 11 years(Nov. l971), during which time the women received home visits by student nurses, the women were again interviewed using the original questionnaire. Additionally, they were asked where they had received information about each question. During the 1$\frac{1}{2}$ year period the visits were made by a total of 112 students. They visited the community twice a week. The result were as follows: Maternal health There was marked improvement in the knowledge of specific aspects of maternal health such as the proper instruments needed for cutting the cord and nutritional precaution of pregnancy (p<0.05). In each case 42.0 percent of more of this knowledge was attributed to information gained from the nursing students. However even after the nursing students'visits, the knowledge of other general areas of maternal remained poor. Child health There were increases in the knowledge of the respondents for the time to supplement breast feeding and for time to wean infants (p<0.05). In each case 35.0 percent or more of this information was attributed to the student. The increase in knowledge regarding types of immunization was more often attributed to the clinic nurse than to the nursing students. Knowledge of the necessity of booster immunization was poor both before and after the visits by the nursing students. Family planing There were significant increases in correct information regarding the time of I.U.D. insertion (P<0.05) and method of taking the oral pill (P<0.05). More than 42.0 percent of the increase was attributed to the nursing students'visits. However there was a slight decrease in correct information about concept of family planning. Tuberculosis There was a general lack of improvement in all areas concerned with tuberculosis. Two thirds of the respondents felt tuberculosis was hereditary and did not know what B.C.G. was. From this study, it could be concluded that in specific area the health knowledge of the female population studied was positively effected by the visits of the nursing students. The study also, suggests, however, that there was a marked unevenness in the overall increase in health knowledge. This raises serious questions which require further research. Suggested areas for further research are (1) Adequacy of the course content preparing nurses for the field experience. (2) A public health nursing manual for student reference. (3) Where and when specific aspects of health can be taught most effectively.

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A Study on the Color Environmental of Neighborhood Parks Considering the Visual Characteristics of Senior Citizens -Focused on the Busan City- (고령자의 시각특성을 고려한 근린공원 환경색채 연구 -부산광역시를 중심으로-)

  • Kim, Hyeyeong;Oh, Jiyoung;Park, Heykyung
    • The Journal of the Convergence on Culture Technology
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    • v.6 no.1
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    • pp.163-169
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    • 2020
  • The purpose of this study is to find out whether the environment is based on the Color Universal Design (CUD, CUD Recommended Color Set Guidebook), which is located in the area with the highest proportion of elderly people in the city of Busan in Korea. Five nearby parks in the walking district of Busan were selected to measure the environmental color with a spectrophotometer(Minolta CM-2600d) and web color search. The range of the color survey was limited to the pavement; public facilities(sign, benches, restroom), and exercise&sports facilities. The results of the study are as follows. Overall, the Y color group was dominant, with similar color usage and intensity, and similar levels of saturation. This was analyzed based on the Color Universal Design theory, suggesting that the visual characteristics of the elderly were not taken into account, and the Neighborhood Park located in Busan was found to lack the environmental color of consideration for the visual characteristics. In addition, this study could act as a basic study that can be applied to social and environmental colors that reflect the color perception and cognitive characteristics of the elderly.

Modeling the Controllable Parameters of Radon Environment System with Dose Sensitivity Analysis (실내 라돈환경계의 선량감도분석에 의한 제어매개변수 모델링)

  • Zoo, Oon-Pyo;Chang, Yi-Young;Kim, Kern-Joong
    • Journal of Radiation Protection and Research
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    • v.16 no.2
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    • pp.41-54
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    • 1991
  • This paper aimed to analyse dose sensitivity to the controllable parameters of indoor radon $(^{222}Rn)$ and its decay products (Rn-D) by applying the input~output linear system theory. Physical behaviors of $^{222}Rn\;&\;Rn-D$ were analyzed in terms of $(^{222}Rn)$ gas -generation, -migation and -infiltration to indoor environments, and the performance output-function, i. e. mean dose equivalent to Tracho-Bronchial (TB) lung region, was assessed to the following extented ranges of the controllable paramenters; a) the ventilation rate $constant({\lambda}_v)\;:\;0{\sim}50[h^{-l}].\;b)$ the attachment rate $constant({\lambda}_a)\;:\;0{\sim}500[h^{-l}].\;c)$ the unattached-deposition rate constant (${\lambda}^u_d)\;:\;0-50[h-l]$. A linear input-output model was reconstructed from the original models in literatures, as follows, which was modified into the matrices consisting of 111 nodal equations; a) indoor $^{222}Rn\;&\;Rn-D$ Behaviour; Jacobi-Porstendoerfer-Bruno model.

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Water Supply Reliability Revaluation For Agricultural Water Supply Pattern Changes Considering Climate Changes (기후변화에 따른 농업용수공급패턴의 변화로 인한 이수안전도변화분석)

  • Choi, Young-Don;Ahn, Jong-Seo;Shin, Hyun-Suk;Cha, Hyung-Sun
    • Proceedings of the Korea Water Resources Association Conference
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    • 2010.05a
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    • pp.273-277
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    • 2010
  • This research was performed to examine changes in the timing of the growth of crops along with changes in temperatures due tochanges and to analyze the change of water-supply-reliability by adding an analysis of the change of agricultural water supply patterns in the basin area of Miryang dam in Korea. Had-CM3 model from U.K. was the tool adopted for the GCM model, a stochastic, daily-meteorology-generation-model called LARS-WG was alsoused for downscaling and for the climate change scenario (A1B) which represents Korea's circumstances best. First of all, to calculate changes in the timing of the growth of crops during this period, the theory of GDD was applied. Except for the period of transplanting and irrigation, there was no choice but to find the proper accumulated temperature by comparing actual temperature data and the supply pattern of agricultural use due to limited temperature data. As a result, proper temperatures were found for each period. $400^{\circ}C$ for the preparation period of a nursery bed, $704^{\circ}C$ for a nursery bed's period, $1,295^{\circ}C$ for the rice-transplanting period, $1,744^{\circ}C$ for starting irrigation, and $3,972^{\circ}C$ for finishing irrigation. To analyze future agricultural supply patter changes, the A1B scenario of Had-CM3 model was adopted, and then Downscaling was conducted adopting LARS-WG. To conduct a stochastical analysis of LARS-WG, climate scenarios were generated for the periods 2011~2030, 2046~2065, 2080~2099 using the data of precipitation andMax/Min temperatures collected from the Miryang gauging station. Upon reviewing the result of the analysis of accumulated temperatures from 2011~2030, the supply of agricultural water was 10 days earlier, and in the next periods-2046~2065, 2080~2099 it also was 10 days earlier. With these results, it is assumed that the supply of agricultural water should be about 1 month ahead of the existing schedule to meet the proper growth conditions of crops. From the results of the agricultural water supply patterns should be altered, but the reliability of water supply becomes more favorable, which is caused from the high precipitation change. Furthermore, since the unique characteristics of precipitation in Korea, which has high precipitation in the summer, water-supply-reliability has a pattern that the precipitation in September could significantly affect the chances of drought the following winter and spring. It could be more risky to make changes to the constant supply pattern under these conditions due to the high uncertainty of future precipitation. Although, several researches have been conducted concerning climate changes, in the field of water-industry, those researches have been solely dependent on precipitation. Even so, with the high uncertainty of precipitation, it is difficult for it to be reflected in government policy. Therefore, research in the field of water-supply-patterns or evapotranspiration according to the temperature or other diverse effects, which has higher reliability on anticipation, could obtain more reliable results in the future and that could result in water-resource maintenance to be safer and a more advantageous environment.

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An Evaluation on Quality of Field Trial Protocol using Pay Factor and Analysis of Fatigue Life (지불계수를 이용한 시험포장구간의 품질평가와 피로수명 분석)

  • Lee, Jae-Hack;Rhee, Suk-Keun;Kim, Seong-Min;Hwang, Sang-Min
    • International Journal of Highway Engineering
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    • v.11 no.4
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    • pp.133-142
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    • 2009
  • This research is performed to estimate quality of trial pavement for construction and analyze effect of fatigue life by using the pay factor. Specially, asphalt content which is difficult to control the pavement quality, is selected by pay adjustment standard factors and pay factor is calculated by asphalt content. This research is also analyzed to present relation of fatigue life according to asphalt content, to evaluate quality of the road pavement by calculating pay factor of sampling trial field mixture 2 times. This research confirms that it is different quality of road pavement according to pay factor changes. To analyze the fatigue life of pavement by using asphalt mixture for trial field. As a result, it is conformed that high pay factor could be high fatigue life of trial field. This means that pay factor using probability theory reflects road pavement fatigue life. Also, this study is included that beam fatigue test manufacturing specimen such as mixing type of plant which purvey asphalt mixture to trial field, compared with fatigue life of trial field. As a result, the fatigue life of specimen that is manufactured by mix type is higher than trial field specimen. This means that performance of road pavement can be reduced by gradation or other effects. Therefore, to exactly evaluate the quality of road pavement, pay factor should be calculated appling various pay adjustment standard factors such as gradation, air-void in U.S. states which is adopted pay adjustment.

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A Study on the Relationship between the Evaluation of Morality on the Korean Drama Characters and the Drama Enjoyment and Quality Evaluation by Foreign Audience (외국 시청자들의 한국 드라마 등장인물에 대한 도덕성 평가와 드라마 '흥미도'와 '질 평가'와의 관계 분석)

  • Lee, Hye Eun;Yu, Sae-Kyung;Chung, Yoonkyung;Lee, Eugene
    • The Journal of the Korea Contents Association
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    • v.17 no.5
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    • pp.357-365
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    • 2017
  • In this study, we examined how the United States, Chinese, and Japanese viewers perceive the morality of the main characters in the family drama 'Take Care of Mom' and the influence of the perceived morality has on drama enjoyment and quality evaluation. Results show that the viewers from all three countries evaluated 'Hoonjae' favorably and evaluated selfish older brother, 'Hyung Kyu', unfavorably. This means there are common norms that exist in all three countries for judging the good and evil in a drama. However, the main female characters that played opposing characteristics were evaluated differently from all three countries. This is because the relationship between parents and children, and the role of mother and woman were perceived differently from each country. These results support the argument that consumption of drama may differ by viewer's cultural background. Additionally, the research hypothesis that 'moral evaluation of major characters will influence the drama enjoyment and evaluation of the drama quality' was not supported in China and Japan, and was only supported by the U.S. viewers.

The Chemical Bond of Cu Atom in Layer and Chain for Y123 and Y124 Superconductors (Y123 초전도체 및 Y124 초전도체에서 층과 사슬에 존재하는 구리 원자의 화학결합)

  • Man Shick Son;U-Hyon Paek;Lee Kee-Hag
    • Journal of the Korean Chemical Society
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    • v.36 no.4
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    • pp.477-484
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    • 1992
  • Using semiempirical molecular orbital method, ASED-MO of extended Huckel Theory, we were investigated chemical bonds and electronic properties of Cu atom in a chain and a layer for Y123 and Y124 superconductors from VEP (valence electron population), DOS (density of state), and COOP (crystal orbital overlap population). In order to investigate environmental effects of Cu atom for Y123 and Y124 superconductors, we introduced charged cluster models with point charge and without point charge into our calculations. As a result of ASED-MO calculations, the Cu atom in the layer acts as electron acceptor and the Cu atom in the chain acts as electron donor for Y123 and Y124 superconductors. The oxidation state of Cu atom for Y123 and Y124 superconductors without point charge is higher in the chain than in the layer. The oxidation state of Cu atom in the layer for Y123 superconductor is higher than that in the layer for Y124 superconductor. The Cu atom in the layer and the chain for Y123 superconductor does not largely affect on the environmental effect. However, the Cu atom in the layer and the chain for Y124 superconductor does largely affect on it. Also, electron population and chemical bonding of Cu1-O4, Cu2-O4, and Cu1-Cu2 for Y123 superconductor are far different from Y124 superconductor.

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CFD ANALYSIS OF TURBULENT JET BEHAVIOR INDUCED BY A STEAM JET DISCHARGED THROUGH A VERTICAL UPWARD SINGLE HOLE IN A SUBCOOLED WATER POOL

  • Kang, Hyung-Seok;Song, Chul-Hwa
    • Nuclear Engineering and Technology
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    • v.42 no.4
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    • pp.382-393
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    • 2010
  • Thermal mixing by steam jets in a pool is dominantly influenced by a turbulent water jet generated by the condensing steam jets, and the proper prediction of this turbulent jet behavior is critical for the pool mixing analysis. A turbulent jet flow induced by a steam jet discharged through a vertical upward single hole into a subcooled water pool was subjected to computational fluid dynamics (CFD) analysis. Based on the small-scale test data derived under a horizontal steam discharging condition, this analysis was performed to validate a CFD method of analysis previously developed for condensing jet-induced pool mixing phenomena. In previous validation work, the CFD results and the test data for a limited range of radial and axial directions were compared in terms of profiles of the turbulent jet velocity and temperature. Furthermore, the behavior of the turbulent jet induced by the steam jet through a horizontal single hole in a subcooled water pool failed to show the exact axisymmetric flow pattern with regards to an overall pool mixing, whereas the CFD analysis was done with an axisymmetric grid model. Therefore, another new small-scale test was conducted under a vertical upward steam discharging condition. The purpose of this test was to generate the velocity and temperature profiles of the turbulent jet by expanding the measurement ranges from the jet center to a location at about 5% of $U_m$ and 10 cm to 30 cm from the exit of the discharge nozzle. The results of the new CFD analysis show that the recommended CFD model of the high turbulent intensity of 40% for the turbulent jet and the fine mesh grid model can accurately predict the test results within an error rate of about 10%. In this work, the turbulent jet model, which is used to simply predict the temperature and velocity profiles along the axial and radial directions by means of the empirical correlations and Tollmien's theory was improved on the basis of the new test data. The results validate the CFD model of analysis. Furthermore, the turbulent jet model developed in this study can be used to analyze pool thermal mixing when an ellipsoidal steam jet is discharged under a high steam mass flux in a subcooled water pool.

Director Yim Jin-Taek's Grounded Aesthetics of Community-based Theatre (임진택의 공동체 지향 연출론: 공동체적 세계관과 미학의 발현 -1970년대와 80년대 대학 공동체 마당굿 퍼포먼스 연출 시기에 초점을 맞추어-)

  • Lee, Gangim
    • Journal of Korean Theatre Studies Association
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    • no.48
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    • pp.289-332
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    • 2012
  • In this paper, based on the theory of performance studies and community-based theatre, I venture to explicate the socio-political significance of director Yim Jin-Taek's community-based performance called 'madanggut', which is heavily based on elements of indigenous culture. Yim's madanggut utilizes elements of indigenous cultures and searches for 'the Korean ethnic (arche)type' as 'the ideal Korean type' or 'genuine Korean-ness' for the reconstruction of 'the Korean ethnic community.' This paper interrogates the major task of Yim Jin-Taek's madanggut, which ideologically promulgates the idea of ethnocentric patriarchy supported by the traditional (mainly Confucianist) notion of 'community' - inquiring if this type of theatre can provide useful and practical prospects for imagining a more democratic and plural civilian society in Korea today, when the interaction of globalization, nationalism, regionalism, and localism simultaneously impact our everyday life and cultural identification. Regarding the recent global phenomenon of the resurgence of nationalism, I looked at madanggut's use of symbolic resources from the past for imaginative communal bonding as a nation. But, the claimed homogeneity of the national past by means of 'nation conflation' of different social groups is an illusionary conceptualization, and the national historiography silences memories of the marginalized groups and denies their histories. It is certain that in Korea nationalism has historically performed an important function during the colonization and democratization period. Nevertheless, as Yim's Nokdukkot realized, it cannot be overlooked that as a representative of 'the Korean ethnic community,' 'the protecting man/the sacrificial woman' is contradictory to the plural and lateral thinking of participatory democracy in community-building. It is time to think about a new political language that relates individuals to the community and nation. 'The ethnic type' cannot represent the whole nation and the members of the nation should be the examples of the community they belong to for a more democratic society. I have selected Yim's several community-based works mainly from the 1970s to the 1980s since the works provide grounding images, symbols, metaphors, and allegories pertinent to discussing how 'the Korean ethnic community' has been narrativized through the performances of madanggut during the turbulent epoch of globalization. I hope that this paper presents Yim's grounded aesthetics of community-based theatre with fully contoured critical views and ideas.