• Title/Summary/Keyword: middle span

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Real-time Vibration Control of Bridges by MR damper and Lyapunov Control Algorithm (MR댐퍼 및 Lyapunov제어알고리즘을 이용한 교량 구조물의 실시간 진동제어)

  • Heo, Gwang-Hee;Jeon, Joon-Ryong;Park, Seung-Bum;Oh, Sung-Keun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.4
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    • pp.55-61
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    • 2010
  • This paper is concerned with an experimental research to random vibration control caused by external loads specially in bridges which tend to be structurally flexible. Experimenting on a reduced structure modelled on Seohae Grand Bridge, we inflicted a reduced form of El-centro wave on the model structure to a proper proportion. On the center of its middle span, we placed a shear type MR damper which was to control its vibration and also acquire its structural responses such as displacement and acceleration at the same site. The experiments concerning controlling vibration were performed according to a variety of theories including un-control, passive on/off control, and Lyapunov stability theory. Its control performance was evaluated in terms of the peak absolute displacements, the peak absolute accelerations and the total power required to control the bridge which differ from each different experiment method. Among all the methods applied in this paper, case of Lyapunov control method turned out to be the most effective to reduces of displacement and acceleration. Also, this method could to decrease consuming of external power for vibration control. Finally, it was noteworthy that Lyapunov control method was specially effective in the vibration control employing a semi-active damper such MR damper.

Effects of Omahwan(OMH) on CD4+, CD8+ T cell and Immune Organ Index in Rat (오마환(烏麻丸)이 백서(白鼠)의 혈액내(血液內) CD4+, CD8+ T cell 및 면역기관(免疫器官) 장기지수(臟器指數)에 미치는 영향(影響))

  • Lee Song-Shil;Lee Sang-Jae;Kim Kwang-Ho
    • Journal of Society of Preventive Korean Medicine
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    • v.5 no.1
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    • pp.76-89
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    • 2001
  • OMH which is known for its properties of recruiting vitality, is composed of Polygonum multiflorum Thunb. and Sesamum indicum DC.. This formula is known to possess the properties of recruiting vitality, blackening white hair and expanding life span. 16-week-old SD-Rats were treated with OMH for 16 days. After 24 hours, the rats were treated with MTX(Mthotrexate is oral administrated for 4 days(1mg/kg/day), in order to lower immunity. Then, These rats were classified in to groups, the N-16 group(not specially tested), the Control group(MTX), the OMH-L group(2.5% OMH+MTX)&the OMH-H group(10% OMH+MTX) and 6 rats were assigned to each group. After 18 hours from MTX treatment the organ index of the rats from each group Thymus and Spleen were measured. The percentage of CD+4, CD8+ T cell were measured and compared by flow cytometer. 1) Rats from the OHM-L&OMH-H group showed higher organ indexes of the Thymus and Spleen compared to the rats from the Control Group. This proves that OMH possesses the properties to mitigate degenerations of immunity($F_{thymus}=20.162,\;F_{spleen}=5.882$, ANDVA, p<0.05). 2) The rats from the two OMH groups showed higher rates of CD4+ T cell counts compared to the control group(F=26.906, ANOVA, p<0.05). CD8+ T cell showed lower rates compared to the Control group, but showed no differences within the two OMH groups(F=1.254, ANOYA, p>0.05). CD4+/CD8+ showed higher rates in the two OMH groups compared to the control group which can be thought as a proof that OMH prevents depression of immune response(F=10.554, ANOVA, p<0.05). In this test 16 week-old rats were used, which can be considered as the middle and prime age of the human being. These rats were treated with OMH which ended up showing properties of mitigating degeneration of immune responses and maintaining T-cell rates within the blood. It was possible to study that OMH possesses the properties to increase immune responses.

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The Meaning of Dating and Marriage among Well-Educated Korean Couples at the Optimal Marriageable Age (고학력 결혼적령기 커플들의 연애와 결혼에 대한 의미 및 젠더 정체성)

  • Sin, Hye Lim;Joo, Susanna
    • Journal of Family Relations
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    • v.21 no.1
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    • pp.77-98
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    • 2016
  • Objectives: The aim of this study was to explore perceived meanings of dating and marriage among well-educated Korean couples who were in optimal marriageable ages. Particularly, an emphasis was placed on finding out where the traditional gender norms and post-modern contexts intersect on the couples' course of dating and marriage. Method: We undertook a qualitative analysis of 8 couples (age: 26-34) dating. Participants were limited to university graduates of upper-middle rank universities in Seoul, South Korea. The rationale for choosing such sample was based on the idea that characteristics of class is inherent in the act of dating and marriage, and that such characteristics lead to different contextual experiences in dating and marriage. This study was based on interviews conducted over a three-month time span. The interviews were first transcribed into research text and then subjects and key categories were drawn from the transcripts for analysis. Results: Participants sought meanings of joy, learning, and self-improvement in dating, and they were free from traditional gender norms in their romantic relationships. They viewed marriage as having a permanent companionship with their partner, becoming independent from their parents, and/or a social norm to be followed. Participants reported mixed perceptions about marriage in such fashion that they described their parents' relationship in terms of a gendered leader-supporter relationship, while viewing their own relationship as being genderless partners. In transition to parenthood, however, they regressed to traditional gender norms dichotomized as women being a homemaker and men being a breadwinner. In sum, participants displayed expectations that were inconsistent with regard to dating and marriage over the study period. That is, during the course of dating and early marriage, they did not hold separated gender norms; however, when transitioning from being a newly married couple to giving their first childbirth, expectations shifted to traditional gender norms and values. Conclusion: This suggests that it is not marriage, but the experience of childbirth and motherhood, which strengthen traditional gendered norms, engendering regeneration of the gender norms in families. The results indicate that there is a need to promote co-parenting behavior among the newly-married couples and to educate gender equality about parent roles or for parents in South Korea so that they can overcome traditional gendered norms in family.

Experimental Investigation on Post-Fire Performances of Fly Ash Concrete Filled Hollow Steel Column

  • Nurizaty, Z.;Mariyana, A.A.K;Shek, P.N.;Najmi, A.M. Mohd;Adebayo, Mujedu K.;Sif, Mohamed Tohami M.A;Putra Jaya, Ramadhansyah
    • International Journal of High-Rise Buildings
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    • v.10 no.4
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    • pp.335-344
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    • 2021
  • In structural engineering practice, understanding the performance of composite columns under extreme loading conditions such as high-rise bulding, long span and heavy loads is essential to accuratly predicting of material responses under severe loads such as fires or earthquakes. Hitherto, the combined effect of partial axial loads and subsequent elevated temperatures on the performance of hollow steel column filled fly ash concrete have not been widely investigated. Comprehensive test was carried out to investigate the effect of elevated temperatures on partial axially loaded square hollow steel column filled fly ash concrete as reported in this paper. Four batches of hollow steel column filled fly ash concrete ( 30 percent replacement of fly ash), (HySC) and normal concrete (CFHS) were subjected to four different load levels, nf of 20%, 30%, 40% and 50% based on ultimate column strength. Subsequently, all batches of the partially damage composite columns were exposed to transient elevated temperature up to 250℃, 450℃ and 650℃ for one hour. The overall stress - strain relationship for both types of composited columns with different concrete fillers were presented for each different partial load levels and elevated temperature exposure. Results show that CFHS column has better performance than HySC at ambient temperature with 1.03 relative difference. However, the residual ultimate compressive strength of HySC subjected to partial axial load and elevated temperature exposure present an improvement compared to CFHS column with percentage difference in range 1.9% to 18.3%. Most of HySC and CFHS column specimens failed due to local buckling at the top and middle section of the column caused by concrete crushing. The columns failed due to global buckling after prolong compression load. After the compression load was lengthened, the columns were found to fail due to global buckling except for HySC02.

Study on Affecting Factors for the Segmental Joint Behavior of Spliced Girder Bridges (분절교량 접합부 거동의 영향인자에 대한 연구)

  • Nam, Jin-Won
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.23 no.3
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    • pp.9-16
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    • 2019
  • Recently, precast PSC girder bridges have been widely applied for short and middle span bridges. The construction of the spliced girder bridges has been increasing to overcome the length limit of girder and transportation restrictions. In case of the spliced girder, the integrity of the segmental joints is very important to secure the structural soundness of bridge because the discontinuity on the segmental joints between adjacent segments could be vulnerable point. The study of segmental joint behavior with different influence factors of joint type, shear key installation, confining force is very important. In this research, finite element analysis and scaled model test with different shear key shapes and confining forces were carried out and the comparative study was performed to evaluate the segmental joint behavior of precast spliced PSC girder bridge. It was confirmed that the installation of shear key with height and depth ratio of 1/2~1/3 and applying of confining force of 1/2 of the concrete strength at the joint was effective in improving the integrity of segmental joint. In addition, the field loading test for existed precast spliced PSC girder bridge was performed and the measurement of the difference of deflection between adjacent segments at segmental joint was proposed as the assessment solution of the integrity of segmental joint.

Types of Retirement Satisfaction and Life Satisfaction among Middle and Older Adults: Focusing on Gender Differences (중고령자의 은퇴 만족 유형과 삶의 만족도 : 성별에 따른 차이를 중심으로)

  • Cho, Kyuyoung;Jun, Hey Jung;Lee, Eun Jee
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.4
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    • pp.371-381
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    • 2019
  • This study explored how retirement satisfaction or dissatisfaction influences on retirees' life satisfaction, comparing to workers and the gender differences were examined. The study sample was 2,609 persons (1,886 workers, 723 retirees) aged 45 or older who participated in the 1-2 waves of the Korean Longitudinal Study of Ageing (KLoSA), and the retirees were classified into continuously dissatisfied retirees and satisfied retirees during wave 1 and 2. Using SPSS 21.0, the multiple regression models were examined, and in order to clarify the gender difference, the multi-group analysis and the wald-test were conducted to test the difference of the regression coefficients according to gender using Mplus 7.3. According to the results, the life satisfaction of dissatisfied retirees was lower than that of the employed, but when satisfied with retirement, the life satisfaction was higher than that of the employed. In addition, the dissatisfied retirees in both gender were less satisfied with life than the employed, and this effect was greater in female group. However, the life satisfaction of female satisfied with retirement was higher than that of the employed, whereas the evidence of the male influence was not found to be significant. Based on the results of this study, discussion about heterogeneity of retirees and gender differences in life span were presented.

Investigation of Impact Factor Variation of Open-Spandrel Arch Bridges According to Spacing Ratio of Vertical Members (수직재 간격비에 따른 개복식 상로 아치교의 충격계수 변화 분석)

  • Hong, Sanghyun;Oh, Jongwon;Roh, Hwasung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.24 no.5
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    • pp.45-52
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    • 2020
  • An open-spandrel arch bridges, which consists of slab deck, arch rib, and vertical members, shows a various level of moment and axial forces according to the supporting boundary condition of arch rib and vehicle speeds. Also, the definition of impact factor accepts any kind of response parameters, not only displacement response at slab deck. The present study considers concrete open-spandrel arch bridges constrained with fixed conditions at the ends of arch rib and investigates the impact factor variation due to moving load speeds, response parameters, measuring locations, and vertical member spacing ratio of the bridges. The results of Reference model show that the impact factor is biggest when the reactive moment resulted at the vehicle-inducing opposite end of the arch rib is applied. The peak impact factor is a similar level obtained for the middle of the span adjacent to the slab deck center, but it is 19% higher than the peak impact factor calculated using the axial force developed at the same location. Reducing the spacing ratio of the vertical members as half as the reference model whose ratio is 1/9.375 produces a similar level of the moment-based peak impact factor compared to the reference model. However, when the spacing ratio is doubled, the peak impact factor is 4.4 times greater than the reference model.

Chronic pain control in patients with rheumatoid arthritis (만성통증 환자의 통증 조절)

  • Eun, Young
    • Journal of muscle and joint health
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    • v.2 no.1
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    • pp.17-40
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    • 1995
  • Rheumatoid arthritis is the one of the chronic diseases, one of its major symptoms is a chronic pain. Despite developing medical treatment and surgical techniques, it is suggested that to control the pain is the goal of the treatment. But pain is an inner experience and even those closest to the patient cannot truly observe its progress or share in its suffering. The National Academy of Sciences Institute of Medicine's report on Pain and Disability concluded that there is no objective measure of pain-(exactly) no pain thermometer-nor can there ever be one, because the experience of pain is inseparable from personal perception and social influence such as culture. To explore chronic pain experience is to understand the process and property of the patient's perception of pain through the response to pain, the coping with pain, and the adaptation to pain. Therefore a qualitative study was conducted in order to gain an understanding of pain experience of patients with RA in korea. I used naturalistic inquiry as a research methodology, which had 5 axioms, the first is that realities are multiple, constructed, and holistic, the second is that knower and known are interactive, inseparable, the third is only time and context bound working hypotheses(idiographic statements) are possible, the forth is all entities are in a state of mutual simultaneous shaping, so that it is impossible to distinguish causes from effects and the last is that inquiry is value-bound. Purposive sampling was conducted as a sampling. 20 subjects who experienced pain over 10 years, lived in middle-sized city and big city in Korea, and 17 women and 3 men. The subject's age was from 32 to 62 (average 48.8), all were married, living with their spouse and children, except two-one divorced and the other widow before they became ill. I collected data using In depth structured interview. I had interviews two or three times with each subject, and the interviews were conducted at each subject's home. Each interview lasted about two hours an average. A recording was taken with the consent of the subject. I used inductive data analysis-such as unitizing and categorizing. unitizing is a process of coding, whereby raw data are systematically transformed and aggregated into units. Categorizing is a process wherby previously unitized data are organized into categories that provide descriptive or inferential information about the context or setting from which the units were derived. This process is used constant comparative method. The pain controlling process is composed of behavior of pain control. The behaviors of pain control are rearranging of ADL, hiddening role conflict, balancing treatment, and changing social relation. Rearranging of ADL includes diet management, sleep management, and the adjustment of daily life activities. The subjects try to rearrange their daily activities by modified style of motions, rearranging time span & range of activities, using auxillary facilities, and getting help in order to keep on the pace of daily life. Hiddening role conflict means to reduce conflicts between sick role and their role as a family member. In this process, the subjects use two modes, one is to control the pain complaints, and the other is to internalize the value which is to stay home is good for caring her children and being a good mother. To control pain complaints is done by 'enduring', 'understanding' the other family members, or making them undersood in order to reduce pain. Balancing treatment is composed of two aspects. One is to keep the pain within the endurable level, the other is to keep in touch with medical personnel in order to get the information of treatment and emotional support. Changing social relation is made by information seeking and sharing, formation of mutual support relation, and finally simplification of social relationships. The subjects simplify their social relationships by refraining from relations with someone who makes them physically and psychologically strained. In particular the subjects are apt to avoid contact with in-laws, and the change of relation to in-laws results in lessening the family boundary. In the course of this process, they confront the crisis of family confict result in family dissolution. This crisis is related to the threat of self-existence. Findings from this study contribute to understanding the chronic pain experience. To advance this study, we should compare this result with other cases in different cultural contexts. I think to interpret these results, korean cultural background should be considered. Especially the different family concept, more broader family members and kinship network, and the traditional medical knowledge influences patients' behavior.

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Effect of temperature on oviposition of Spodoptera frugiperda (Lepidoptera: Noctuidae) and ovipositional characteristics in corn fields (온도가 열대거세미나방 산란에 미치는 영향 및 옥수수 포장에서의 산란 특성)

  • Hyung Cheol Moon;Min Kyung Choi;Su Ji Jang;Jang Ho Lee;Ju Hee Kim;Hyong Gwon Chon
    • Korean Journal of Environmental Biology
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    • v.40 no.3
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    • pp.281-289
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    • 2022
  • The effect of five different constant temperatures (18, 21, 24, 27, and 30±1℃) and a photoperiod of 14 : 10 (L :D) h on the reproduction parameters of Spodoptera frugiperda was studied. The longevity of adult female S. frugiperda decreased with increasing temperature (22.4 days at 21℃ and 13.9 days at 30℃) but not at 18℃. The pre-oviposition period and oviposition period was the shortest at 30℃ compared to the other temperatures. The total fecundity egg count was 887.4, 1,246.4, 1,348.9, 1,154.9, and 1,034.2 at 18, 21, 24, 27 and 30℃, respectively, during its life span. The survival rate of female S. frugiperda decreased rapidly after 13 days at 18℃, after 14 days at 21℃, after 15 days at 27℃, and after 9 days at 24℃, and 30℃. On the third day after the start of oviposition, 50% of the total fecundity was accomplished. In corn fields at less than the 10-leaf stage, the distribution of S. frugiperda egg masses was observed in the middle and lower plant regions, corresponding to 46.8% and 41.4% of the total egg masses, respectively. Egg masses were mostly found on the underside of the leaf blade (abaxial) of corn(66.7%). After releasing S. frugiperda adults on May 12, May 17, May 25, and May 30, the number of eggs per egg mass was 89.9, 88.5, 126.6, and 127.9, respectively. Egg masses of the subsequent generations of S. frugiperda were observed from late June, and the number of eggs per egg mass was 155.8 in late June, 270.7 in early July, and 303.5 in mid-July.