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Vehicle-Bridge Interaction Analysis of Railway Bridges by Using Conventional Trains (기존선 철도차량을 이용한 철도교의 상호작용해석)

  • Cho, Eun Sang;Kim, Hee Ju;Hwang, Won Sup
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.1A
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    • pp.31-43
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    • 2009
  • In this study, the numerical method is presented, which can consider the various train types and can solve the equations of motion for a vehicle-bridge interaction analysis by non-iteration procedure through formulating the coupled equations of motion. The coupled equations of motion for the vehicle-bridge interaction are solved by the Newmark ${\beta}$ of a direct integration method, and by composing the effective stiffness matrix and the effective force vector according to a analysis step, those can be solved with the same manner of the solving procedure of equilibrium equations in static analysis. Also, the effective stiffness matrix is reconstructed by the Skyline method for increasing the analysis effectiveness. The Cholesky's matrix decomposition scheme is applied to the analysis procedure for minimizing the numerical errors that can be generated in directly calculating the inverse matrix. The equations of motion for the conventional trains are derived, and the numerical models of the conventional trains are idealized by a set of linear springs and dashpots with 16 degrees of freedom. The bridge models are simplified by the 3 dimensional space frame element which is based on the Euler-Bernoulli theory. The rail irregularities of vertical and lateral directions are generated by the PSD functions of the Federal Railroad Administration (FRA). The results of the vehicle-bridge interaction analysis are verified by the experimental results for the railway plate girder bridges of a span length with 12 m, 18 m, and the experimental and analytical data are applied to the low pass filtering scheme, and the basis frequency of the filtering is a 2 times of the 1st fundamental frequency of a bridge bending.

Effects of Velocity Structures on Tracer Mixing in a Meandering Channel (사행수로에서 유속구조가 추적물질의 혼합에 미치는 영향)

  • Seo, Il Won;Park, Sung Won
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.1B
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    • pp.35-45
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    • 2009
  • In this study, a laboratory experiment has been performed on a S-curved channel with two curved sections. In the experiments, effects of 3-D velocity structures on mixing characteristics of tracer material were investigated. As a result, it was clearly noticed that the primary flow travels taking the shortest course of the meandering channel and has a very ununiform distribution at the bends. The secondary cell which was developing at the first bend disappears at the crossover, and then, at the next bend, secondary cell is re-developing in the opposite direction. The experimental results show that mixing of tracer is significantly affected by the combined action of ununiform primary flow and secondary cell. The ununiform primary flow separates the tracer cloud in the longitudinal direction, and the secondary cell further separates the retarding tracer cloud mainly in the transverse direction. As a result, these complex flow structures cause separation and spreading of tracer cloud both in the longitudinal and in the transverse directions. The measured dimensionless transverse dispersion coefficients calculated using 2-D routing procedure ranges 0.012-0.875, and is generally proportional to width to depth ratio (W/h). The predicted values calculated by the theoretical equation overestimate slightly the measured transverse dispersion coefficients.

A Study on Antecedents of Suicidal Ideation among Korean Older Adults: A test of the Stress-diathesis Model (노인의 자살 생각에 영향을 미치는 선행요인에 관한 연구: 스트레스 소질 모델(Stress-diathesis Model)을 중심으로)

  • Ahn, Joonhee;Chun, Miae
    • 한국노년학
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    • v.29 no.2
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    • pp.489-511
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    • 2009
  • While late-life suicide has been increasing and become an important issue for public health in Korea, little is known about the phenomenon and its contributing risk factors based on which effective preventive measures can be made. Since suicidal ideation is a major precursor to attempted and completed suicide, the objective of the present study was to reveal primary contributors to suicidal ideation. Data were collected from a cross-sectional survey of 247 community-dwelling Korean older adults (age≥60) in the mid-size city in Korea. The statistical methodology employed a robust hierarchical regression procedure that iteratively downweights outliers. Based on the stress-diathesis model, the study examined major diathesis and stressors directly explaining suicidal ideation. The study also explored the significant interaction among these factors. The findings revealed that living alone and depression were significant main antecedents of suicidal ideation. In addition, neuroticism X life events and neuroticism X depression were significant interaction terms with the strongest explanatory power, which provides an empirical evidence to support the stress-diathesis model in explaining suicidal phenomenon of the Korean elderly. The result demonstrates the theoretical implication as well as the practical implication for developing and implementing late-life suicide prevention strategies. Limitations and directions for future research are discussed.

The Effects of Medical Service Utilizations on Life Satisfaction among the Elderly: Focusing on the Moderating Effects of the Presence of Chronic Illnesses (노년기 의료서비스 이용이 삶의 만족도에 미치는 영향: 만성질환 유무의 조절효과를 중심으로)

  • Jeon, Hae-Sook;Kahng, Sang Kyoung
    • 한국노년학
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    • v.31 no.4
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    • pp.1247-1263
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    • 2011
  • The rapidly aging society entails the increases of medical service utilizations among the elderly. Medical services utilized by the elderly influence their life satisfaction. However, little is known about the effects of medical service utilizations on life satisfaction. Much less is known about whether the effects of medical service utilizations on life satisfaction tend to vary by the presence of chronic health conditions. Including 3,944 individuals aged 65 and over who participated in the 3rd wave of Korean Welfare Panel Study, the current study aims to examine (1) the relationships between medical service utilizations and life satisfaction and (2) whether the effects of medical service utilizations on life satisfaction vary by the presence of chronic health conditions. Data were processed through structural equation modeling(SEM) and multi-group SEM. Results indicate that (1) levels of both outpatient and inpatient service utilizations are related to life satisfaction, whereas levels of health monitoring service utilizations are not and (2) the effects of medical service utilizations varied by the chronic health condition status of the elderly. These results indicate that, in order to enhance levels of life satisfaction, medical services should be strategically utilized by the elderly depending on their chronic health condition status. Based on the findings, we discussed implications for practice and policy, suggesting future research directions based on the limitations of the current study.

A Study on the Effects of Discrimination Experience on Self-image and Self-esteem among the Korean elderly: Moderating Effects of Social and Economic Activity Participation (노인의 차별경험이 자아이미지와 자아존중감에 미치는 영향에 관한 연구: 사회·경제적 참여의 조절효과를 중심으로)

  • Ahn, Joonhee;Kim, Seongyong
    • 한국노년학
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    • v.29 no.4
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    • pp.1645-1663
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    • 2009
  • The purpose of the study is to analyze the mediating effects of self-image on the relationship between experience of discrimination and self-esteem among the elderly in Korea. Furthermore, it is to explore whether these effects are moderated by social and economic activity participation. Data were collected from a cross-sectional survey of 543 community-dwelling Korean older adults (age≥65) drawn from community and senior centers in the mid-size city in Korea. The statistical analysis was performed by a structural equation modeling using LISREL statistical program. The results are fourfold. First, experiences of discrimination exerted the negative effects on physical, dispositional, and competent self-images of the elderly. Second, dispositional and competent self-image brought down by discriminative experiences lowered the levels of self-esteem. Third, social activity participation moderated the negative effects of discrimination experiences on physical and dispositional self-images. It also moderated the effects of dispositional self-image on self-esteem. Fourth, economic activity participation did not show moderating effects on the relationship between experience of discrimination and self-images. Meanwhile, it moderated the effect of competent self-image on self-esteem. These results demonstrate that to improve self-esteem of the elderly population, social welfare policies should make effort to reduce discrimination toward the elderly. Furthermore, social welfare organizations should also try to implement diverse community based programs geared for enhancing social and economic activities for elderly. Limitations and directions for future research are also discussed.

Elderly Women's Adaptation Process on Separation by Death in Rural Areas (농촌여성노인의 배우자 사별 적응과정)

  • Jang, hee Sun;Kim, Yun Jeong
    • 한국노년학
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    • v.31 no.4
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    • pp.939-967
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    • 2011
  • This study observed elderly women's adaptation process on separation by death in rural areas through grounded theory approach and developed its entity theory. Participants for this study were 14 elderly women who have lost their husbands in the last 12 months. The study was conducted for 8 months starting January 2010. Each interview per session took 40 to 90 minutes, study notes were taken on site, and recorded contents were transcribed by the researcher which was myself. The research data were collected by in-depth interview and with help of local community's nurses who were in charge of taking care of the participants. The collected data were analyzed by applying Strauss & Corbin's grounded theory (1998). As a result of study, 80 concepts, 28 subcategories, and 12 categories were deducted during open coding process. Adaptation process on separation by death was process of 'finding a way to live alone' which used strategy of 'attempting a make changes in life', and 'embracing the situation' which were influenced by conciliatory conditions of 'degree on economic condition', 'change in health', and 'supporting system' which focuses on phenomenon of 'bearing life alone' which is influenced by context condition of 'marital chemistry of couples during lifetime', and 'the couple's leadership during lifetime' together with casual conditions of 'the fall of wall'. The adaptation process accordance to time flow were divided into 4 steps which were step of 'shock and release of emotions', step of 'longing and resentment', step of 'resignation and acceptance', and step of 'life's restructure'. Above results suggest right directions for welfare for the aged and process of 'finding a way to live alone' for participants by controlling several factors and using intervention strategy, and provided basic data required for developing and applying practical welfare mediation.

Exploratory Study on the Construction of Sewol Ferry Memorial Space: Focusing on the Perspective of Placeness and Dark Tourism (세월호 기억공간 건립 관련 탐색적 연구: 장소성 및 다크투어리즘 관점을 중심으로)

  • Chun, Myung-Hoon;Ko, Jeong-Min
    • The Journal of the Korea Contents Association
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    • v.22 no.8
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    • pp.126-139
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    • 2022
  • This study aims to present the criteria of location selection and contents composition of Sewol ferry memorial space from the perspective of placeness and dark tourism, one of the main concepts of cultural tourism theory, and to draw academic concepts and implications related to it. First, the location selection of Sewol ferry memorial space was proposed by applying the concept of placeness to each important location, and the direction of the contents composition was presented based on the contents components such as characters, stories, places and dark tourism composition directions. As a result, when the Sewol ferry memorial space is designed in use of systemizing the narrative structure of the storytelling method and implementing it specifically, it is suggested that it is possible to construct a Sewol ferry memorial space by distributing and course-making based on the narrative structure rather than focusing on the location selection of a specific place. In addition, it was argued that the contents composition criteria should be more complex and systematically established and applied considering the connection between placeness and dark tourism when the Sewol ferry memorial space is constructed in various sites like 416 life safety parks and Mokpo New Port. This study, which aims to answer research questions related to major issues based on the perspective of placeness and dark tourism on the Sewol ferry memorial space, is expected to be used as a reference for the construction of the memorial space in the future.

Discrepancy between Parent and Child Report on Quality of Life and Behavioral Problems in Child and Adolescent cancer survivors and Healthy Control Group (소아암 생존자 집단과 건강통제 집단의 삶의 질과 문제행동 비교 및 부모보고와 자기보고의 차이 연구)

  • Kim, M.H.;Chung, C.M.;Rhee, M.A.;Ryu, C.J.;Won, S.C.;Shin, Y. J.
    • Korean Journal of Health Psychology
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    • v.16 no.3
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    • pp.483-500
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    • 2011
  • Since the introductionof modern therapies, more children with cancer have survived their illness. As a result, an interest in the degree of adjustment achieved by cancer survivors has increased. In this study, quality of life and behavior problemsof child and adolescent cancer survivors were compared with those of healthy controls. Also, the patternsof the discrepancy between parent-report and self-report were compared. Childhood cancer survivors aged 8-18 and their mothers were participated in the study. Parent and self report versions of PedQL were administered to assess the quality of life. K-CBCL and K-YSR were further completed to assess internalizing and externalizing behavior problem. Results suggested that cancer survivors generally showed lower quality of life in physical and social domains and more internalizing behavior problem than healthy control group. However, the results were affected by the domain, age group, and informant. The pattern of discrepancy between parent and self report was similar. All parents reported higher levelsof quality of life and lower levels of behavior problems compared to the self reports of their siblings. In assessing internalizing problem behaviors, cancer survivor group showed greater discrepancy than the healthy control group.The implications, limitations, and directions for future research were also discussed.

Identifying Latent Classes in Adolescent's Self-Determination Motivation and Testing Determinants of Classes (자기결정성 이론에 따른 학습동기 변화의 잠재프로파일 분류 및 영향요인 검증)

  • Choi, Hyunju;Cho, Minhee
    • Korean Journal of School Psychology
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    • v.11 no.1
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    • pp.253-274
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    • 2014
  • The present study classified groups based on latent profile of self-determination motivation(amotivation, external motivation, intrinsic motivation), and examined the determinants for each group. The data was collected through panel data of Korea Education Longitudinal Study(KELS), total 5,459 participants who answered questionnaires of self-determination motivation of two times both second grade of middle school and second grade of high school. To identify the change motivational type, standardized residual was conducted using SPSS 17.0., and the latent classes for the change of motivational type was investigated using M-Plus in the frame work of Latent Profile Analysis(LPA). The results indicated that five groups(increase of self-determination, self-determination maintenance, self-determination developmental delay, elf-determination confusion, decrease of self-determination group) were classified based on latent profile. In addition, parental control, academic self-concept, teacher-student relationship, test anxiety, avoidance orientation, gender, father's education, and income were significantly related to each group. Lastly, the implications for directions of the adolescent counseling, limitations and future research are discussed.

An Analysis of Gyeonggi Sinawi Dance in the Fashion of Kim Sukja (김숙자류 경기시나위춤에 관한 고찰)

  • Han, soomoon
    • (The) Research of the performance art and culture
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    • no.22
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    • pp.413-439
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    • 2011
  • This study aims to look for the proper directions of following and developing Gyeonggi sinawi dance in the fashion of Kim Sukja by closely examining its kinds and patterns. First, its characteristics and education reality were investigated. Second, the seven kinds of Gyeonggi sinawi dance Kim Sukja allegedly handed down (according to the 121st Report of the Intangible Cultural Assets) were concretely examined. Third, the composition of each dance pattern was studied. Fourth, various beats used in Gyeonggi sinawi dance were revealed. The late Kim Sukja had outstanding artistic talent and ability in Gyeonggi sinawi dance movements, musical composition, gayageum accompanied singing, and pansori episodes. Behind her were master singer Kim Seokchang (grandfather), father Kim Deoksun (belonging to Hwaseong Artist Board), shaman-mother Jeong Gwiseong, and great dancer Jo Jinyeong. Kim sukja's seven Gyeonggi sinawi dance types were bujeong nori, teo beollim, jinsoe, jeseok, kkaekkeum, ollimchae, and dosal puri (designated as Important Intangible Cultural Asset in 1990). Such beats as seopchae (dosal puri), mori, bal ppeodeurae, bujeong nori, ollimchae, jinsoe, and teo beollim (ban seoreum) were mainly used in Gyeonggi sinawi dance. In sum, Kim Sukja's dance was more than an individual's dance to represent the cultural types and life at that time in Gyeonggi-do and be a very important academic historic material. Therefore, it is the responsibility of the present generation to hand down and develop such invaluable traditional cultural materials.