• Title/Summary/Keyword: Research Methodology

Search Result 10,414, Processing Time 0.042 seconds

Shear Force Variation of Stiffening Girder caused by Vibration of Stay Cable (사장 케이블 진동에 의한 보강형의 전단력 변화)

  • Kim, Hyeon Kyeom;Hwang, Jae Woong;Lee, Myeong Jae
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.29 no.1A
    • /
    • pp.1-8
    • /
    • 2009
  • Stay cable is easily exposed to vibration induced rainy wind effects. There are some problems for not only unexpected vibration but also well-known vibration. An outbreak of displacement by the said effects brings damages such as over-tension of cables and barriers, fatigue of anchorages and dampers, and additional shear force variation of stiffening girders. This study suggests analytic methodology for dynamic tension variation of cables and shear force variation of stiffening girders. Additionally this study announces with dynamic problems for cable stayed bridge briefly. To realize this subject, we divide restoring force into chord component and normal component and then make up the differential equations which can satisfy physical phenomenon for each component. Finally we apply adequate functions such as sinusoidal and parabola in order to reduce these differential equations. Therefore we can meet with good results through a series of above process. As a remarkable result, CIP recommendations (2002) give inadequate solution with over 10% error. However it gives very good solution if parts of our study are reflected at the said recommendations. The fact means that CIP recommendations (2002) well-known as international standard of stay cables are not even concern about this subject yet. For verification of this study, F.E. analysis using E.C.C. with external forces was fulfilled, and the accuracy and conciseness of this study were shown.

Seismic Fragility Analysis for Probabilistic Performance Evaluation of PSC Box Girder Bridges (확률론적 내진성능평가를 위한 PSC Box 거더교의 지진취약도 해석)

  • Song, Jong-Keol;Jin, He-Shou;Lee, Tae-Hyung
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.29 no.2A
    • /
    • pp.119-130
    • /
    • 2009
  • Seismic fragility curves of a structure represent the probability of exceeding the prescribed structural damage state for a given various levels of ground motion intensity such as peak ground acceleration (PGA), spectral acceleration ($S_a$) and spectral displacement ($S_d$). So those are very essential to evaluate the structural seismic performance and seismic risk. The purpose of this paper is to develop seismic fragility curves for PSC box girder bridges. In order to construct numerical fragility curve of bridge structure using nonlinear time history analysis, a set of ground motions corresponding to design spectrum are artificially generated. Assuming a lognormal distribution, the fragility curve is estimated by using the methodology proposed by Shinozuka et al. PGA is simple and generally used parameter in fragility curve as ground motion intensity. However, the PGA has not good relationship with the inelastic structural behavior. So, $S_a$ and $S_d$ with more direct relationship for structural damage are used in fragility analysis as more useful intensity measures instead of PGA. The numerical fragility curves based on nonlinear time history analysis are compared with those obtained from simple method suggested in HAZUS program.

Cracking Behavior of Concrete Bridge Deck Due to Differential Drying Shrinkage (교량 바닥판 콘크리트의 부등건조수축 균열특성에 관한 연구)

  • Yang, Joo Kyoung;Lee, Yun;Yang, Eun Ik;Park, Hae Geun
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.29 no.4A
    • /
    • pp.329-335
    • /
    • 2009
  • The purpose of this study is to provide the efficient method and guideline of controlling the cracking in bridge deck concrete due to differential drying shrinkage. Drying shrinkage cracking is mainly influenced by the moisture diffusion coefficient that determines moisture diffusion rate inside concrete structures. In addition to the diffusion coefficient, surface coefficient of concrete surface and relative humidity of ambient air simultaneously affect the moisture evaporation from concrete inside to external air outside. Within the framework of cracking shrinkage cracking mechanism, it is necessary to conceive the numerical analysis, which involves these three influencing factors to predict and control the shrinkage cracking of concrete. In this study, moisture diffusion and stress analysis corresponding to drying shrinkage on bridge deck are performed with consideration of diffusion coefficient, surface coefficient, and relative humidity of ambient air. From the numerical results, it is found that cracking behavior due to differential drying shrinkage of bridge deck concrete shows different feature according to three influencing factors and the methodology of controlling of drying shrinkage cracks can be suggested from this study.

Development and Effectiveness Analysis of Team Based learning (TBL) for Students Majoring in Skin Care - Focus on Problem Solving Competency and Cooperative Self Efficacy - (피부미용 전공 학생들을 위한 팀기반학습(TBL) 수업 개발 및 적용 효과 분석- 문제해결능력과 협력적 자기효능감을 중심으로 -)

  • Park, Jeong-Yeon
    • Journal of Korea Entertainment Industry Association
    • /
    • v.13 no.7
    • /
    • pp.469-477
    • /
    • 2019
  • The purpose of this study was to develop Team Based Learning (TBL) course for students majoring skin care and analyze the effectiveness as well as derive improvement plans. TBL focuses on putting pre-class learning about learning content and the time saved by it into practice activities that apply what is learned. The ADDIE model and the TBL model were applied as the developmental research methodology, and the 'skin care' subject, which was previously taught by lecture base, was redesigned as a TBL class. In addition, the study developed weekly based pre-class learning materials, quiz items for checking pre-class learning, and the team activities' plan. Then, an experimental study was conducted with 43 university students and the effects of TBL instruction were analyzed as follows. First, students who participated in the TBL class showed higher achievement than those who participated in the lecture class, which is a comparative group, especially in the academic achievement that evaluated the acquisition and application of the major concept. Second, there was no significant difference in pretest and posttest results on problem solving ability and cooperative self-efficacy for TBL students. Third, overall satisfaction with TBL class was 4.0, which is high. The discussion of these findings was described, and three suggestions for improving and researching TBL classes were presented.

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
    • /
    • v.29 no.2
    • /
    • pp.489-511
    • /
    • 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 Empirical Research on Relationship of Consumption Value, Satisfaction, Trust, Loyalty of Green Product in Elderly Consumer (실버 소비자의 친환경 제품에 대한 소비 가치가 만족도, 신뢰, 충성도에 미치는 영향 - 하이브리드 카를 중심으로 -)

  • Hur, Won-Moo;Ahn, Joonhee
    • 한국노년학
    • /
    • v.29 no.1
    • /
    • pp.195-213
    • /
    • 2009
  • The purpose of this study is to analyse how consumption value affects the loyalty of green product through satisfaction and trust among elderly consumers. Data were collected from a cross-sectional survey of 314 older adults (age≥60) in the U. S., who bought and possessed a hybrid car, a representative green product. The statistical methodology is employed a structural equation model. The results demonstrated several important findings. First, perceived social value among elderly population had significant effects on green product satisfaction, while hedonic value did not. Second, both perceived functional value and environment friendly value had a significant positive effect on trust in green products. Third, satisfaction with green products also led to trust in green products. Finally, trust in green products showed their significant effects on loyalty in green product. These results provide practical implications to improve the trust and loyalty in green products among the elderly consumers. Furthermore, by deriving major components of consumption values in green products among the elderly, and analyzing the mechanism of satisfaction, trust, and loyalty, the study emphasizes relationship marketing in implementing "green" marketing strategies.

Honors Program for Gifted Students at University-level ; on Selection and Curriculum (대학 단계의 과학영재 특화교육 프로그램 - 학생 선발 및 교육과정을 중심으로 -)

  • Kwon, Sung-ho;Tschoe, Dong-Seok;Kim, Myung-Sook;Kim, Young-Ah;Kang, Kyung-hee
    • Korean Journal of General Education
    • /
    • v.4 no.1
    • /
    • pp.237-254
    • /
    • 2010
  • For years, poor research and working conditions in the field of science and engineering in Korea led to the migration of gifted students to seek a better academic environment. The primary reason for such a phenomenon is the lack of a coherent education system for gifted students. With the support from the Ministry of Education, Science and Technology and the Korea Foundation for the Advancement of Science & Creativity, Hanyang University launched an exploring project to introduce an Honors Program, aiming to provide specialized and systematic learning opportunities as well as supporting greater academic achievements for gifted students at university-level. Students admitted to this program were selected not by conventional standards but by competency-based selection process, assessed through an in-depth interview. The specific goal of this program is to prepare gifted and talented students not only for an academic pioneer with the highest caliber in the field of science, but also for a global leader equipped with a creative view as well as integrity and a convergent mind. Distinctive features of this program include emphasis on fundamental science and consilience, problem solving skills, first-hand education, interpersonal skills, and global communication skills as well as individualization of the learning experience, among many others. This paper provides a short glimpse of the focus and methodology Honors Program in Hanyang University offers.

Economic Effects of Policy Loans: Focusing on Alleviation Effect of Investment Liquidity Constraint (정책융자의 경제적 성과분석: 투자의 유동성 제약완화 중심으로)

  • Nam, Joo-ha
    • International Area Studies Review
    • /
    • v.15 no.1
    • /
    • pp.173-193
    • /
    • 2011
  • Most of the research regarding economic effects of policy loans has thus far been focused on whether policy loans can improve the financial status or the management performance of small and medium enterprises (SMEs). Unlike previous researches, this study implemented an empirical analysis focused on the contribution of policy loans to easing the liquidity restriction of investment. To analyze whether investment liquidity restriction can be alleviated or not, this study attempted an empirical analysis utilizing the nonlinear Euler equation induced through optimization of investment and GMM (generalized method of moments) as its analysis methodology. With the SMEs that received policy financing from the Small and medium Business Corporation (SBC) in 2004, this study analyzed three years of panel data before(2001~2003) and after(2004~2006) receipt of policy loans. According to the empirical results, it appears that policy loans had effects on resolving liquidity restriction of investment, implying that policy financing eases the liquidity restriction of SME investment and would contribute to the growth and development of SMEs. Further, I checked robustness of empirical results using Tobin's q model. The empirical results also support that policy loans help to resolve liquidity constraint. With these results, it is understood that the critical view to date, which has emphasized the ineffectiveness of policy financing due to it having no or insignificant economic effects, may be wrong.

University Student's Beliefs, Attitudes and Intention with Regard to Applying for Jobs in SME (중소기업 취업에 관한 대학생들의 신념, 태도 및 취업의도에 관한 연구)

  • Moon, Sun-Jung
    • Korean small business review
    • /
    • v.39 no.3
    • /
    • pp.57-76
    • /
    • 2017
  • While the unemployment rate is rising rapidly due to recent economic recession at home and abroad, university students' reluctance to apply for jobs in Small and Medium Enterprises (SME's) causes instability in manpower supply and demand and social unrest. To provide insights for solving the problem, this study explores how beliefs and attitudes of university students influence their intention to apply for jobs in SME's using Theory of Planned Behavior proposed by Icek Ajzen. This study followed the 2-stage survey methodology suggested by Ajzen. In the first stage of pilot study, a small sample of university students was used to illicit readily accessible behavioral outcomes, normative referents, and control factors. In the second stage of main study, the standard questionnaire was designed and administered and data were collected and analysed using the PLS Structural Equation Modeling (SEM) technique. PLS-SEM was used instead of Covariance Based (CB)- SEM considering the exploratory nature of this study. In overall, the results showed that TPB is very effective in explaining and predicting the university student's intention to apply for jobs in SEM's. Gender turned out to be a significant moderator variable in the relations between intention and its influence factors. Student's scholastic performance showed a negative correlation with intention. More research efforts need to be exerted to better understand university student's job seeking behavior.

A Study on Dataset Generation Method for Korean Language Information Extraction from Generative Large Language Model and Prompt Engineering (생성형 대규모 언어 모델과 프롬프트 엔지니어링을 통한 한국어 텍스트 기반 정보 추출 데이터셋 구축 방법)

  • Jeong Young Sang;Ji Seung Hyun;Kwon Da Rong Sae
    • KIPS Transactions on Software and Data Engineering
    • /
    • v.12 no.11
    • /
    • pp.481-492
    • /
    • 2023
  • This study explores how to build a Korean dataset to extract information from text using generative large language models. In modern society, mixed information circulates rapidly, and effectively categorizing and extracting it is crucial to the decision-making process. However, there is still a lack of Korean datasets for training. To overcome this, this study attempts to extract information using text-based zero-shot learning using a generative large language model to build a purposeful Korean dataset. In this study, the language model is instructed to output the desired result through prompt engineering in the form of "system"-"instruction"-"source input"-"output format", and the dataset is built by utilizing the in-context learning characteristics of the language model through input sentences. We validate our approach by comparing the generated dataset with the existing benchmark dataset, and achieve 25.47% higher performance compared to the KLUE-RoBERTa-large model for the relation information extraction task. The results of this study are expected to contribute to AI research by showing the feasibility of extracting knowledge elements from Korean text. Furthermore, this methodology can be utilized for various fields and purposes, and has potential for building various Korean datasets.