• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2007년도 추계학술대회 논문집
• /
• pp.1158-1164
• /
• 2007

Recently, the demand on the practical application of life-cycle cost effectiveness for design and rehabilitation of civil infrastructure is rapidly growing unprecedentedly in civil engineering practice. Accordingly, it is expected that the life-cycle cost in the 21st century will become a new paradigm for all engineering decision problems in practice. However, in spite of impressive progress in the researches on the LCC, so far, most researches in Koreahave only focused on roadway bridges, which are not applicable to railway bridges. Thus, this paper presents the formulation models and methods for uncertainty-based LCCA for railroad bridges consideringboth objective statistical data available in the agency database of railroad bridges management and subjective data obtained form interviews with experts of the railway agency, which are used to anew uncertainty-based expected maintenance/repair costs including lifetime indirect costs. For reliable assessment of the life-cycle maintenance/repair costs, statistical analysis considering maintenance history data and survey data including the subjective judgments of railway experts on maintenance/management of railroad bridges, are performed to categorize critical maintenance items and associated expected costs and uncertainty-based deterioration models are developed. Finally, the formulation for simulation-based LCC analysis of railway bridges with uncertainty-based deterioration models are applied to the design-decision problem, which is to select an optimal bridge type having minimum Life-Cycle cost among various railway bridges types such as steel plate girder bridge, and prestressed concrete girder bridge in the basic design phase.

• 대한기계학회논문집A
• /
• 제26권2호
• /
• pp.365-373
• /
• 2002

For gas turbine engines, the safe life methodology has historically been used fur fatigue life management of failure critical engine components. The safe retirement limit is necessarily determined by a conservative life evaluation procedure, thereby many components which have a long residual life are discarded. The objective of this study is to introduce the damage tolerant design concept into the life management for aircraft engine component instead of conservative fatigue life methodology which has been used for both design and maintenance. Crack growth data were collected on a nickel base superalloy which have been subjected to combined static and cyclic loading at elevated temperatures. Stress analysis fur turbine disk was carried out. The program for computing creep-fatigue crack growth was developed. The residual lifes of turbine disk component under various temperatures and conditions using creep-fatigue crack growth data were estimated. As the result of analysis, it was confirmed that retirement fur cause concept was applicable to the evaluation of residual life of retired turbine disk which had been designed based on the conventional fatigue life methodology.

• 국제학술발표논문집
• /
• The 3th International Conference on Construction Engineering and Project Management
• /
• pp.1324-1327
• /
• 2009

Social infrastructure is the basis of public welfare and should be recognized and managed as important assets. Bridge is one of the most important infrastructures to be managed systematically because the impact of the failure is critical. It is essential to monitor the performance of bridges in order to manage them as an asset. But current analytical methods such as predictive modeling and structural analysis are very complicated and difficult to use in practice. To apply these methods, structural and material condition data collection should be performed in each element of bridge. But it is difficult to collect these detailed data in large numbers and various kinds of bridges. Therefore, it is necessary to collect data of major measurement items and predict the life of bridges roughly with advanced information technologies. When certain measurement items reach predefined limits in the monitoring bridges, precise performance measurement will be done by detailed site measurement. This paper describes the selection of major measurement items that can represent the tendency of bridge life and introduces automated bridge data collection test-bed using wireless sensor network technology. The following will be major parts of this paper: 1) Examining the features of conventional bridge management system and data collection method 2) Mileage concept as a bridge life indicator and measuring method of the indicator 3) Test-bed of automated and real-time based bridge life indicator monitoring system using wireless sensor network

• 디지털융복합연구
• /
• 제16권9호
• /
• pp.453-463
• /
• 2018

본 연구는 간호대학생의 생명의료윤리의식, 비판적 사고성향이 연명치료 중단에 대한 태도에 미치는 영향을 파악하기 위한 서술적 조사연구이다. 연구대상은 367명의 간호대학생을 대상으로 2017년 11월부터 12월까지 자료 수집하였으며, 자료 분석은 SPSS Win. 21.0 프로그램을 이용하였다. 연구결과, 연명치료 중단에 대한 태도와 생명의료윤리의식과 유의미한 정적 상관관계가 있었으며, 연명치료중단에 대하 태도에 생명의료윤리의식, 학년, 주관적인 건강상태, 성격으로 나타났으며, 이들 변수의 설명력은 36.6%이었다. 결론적으로 간호대학생의 연명치료 중단에 대한 긍정적 태도 형성을 위해 생명의료 윤리의식을 높일 수 있는 다양하고 체계적인 교육프로그램 개발이 필요하다.

• 영어어문교육
• /
• 제15권3호
• /
• pp.33-57
• /
• 2009

Taking the issues of inequity and power between NES and NNES teachers as a starting point, this qualitative study explores the way the widespread belief of the native speaker fallacy manifests itself in one NNES teacher's teaching life and is linked to the teacher's understanding of herself as an English teacher. Guided by critical applied linguistics (Pennycook, 2001) and using Bourdieu's (1991) theorization of symbolic violence, I conducted an instrumental case study (Stake, 1995) in an ESL writing class at a US university. I collected data through classroom observations and interviews over a nine-month period and analyzed the data using the constant comparison method (Glaser and Strauss, 1967). The findings illustrate the ways the dominant ideology of the native speaker fallacy works to maintain and reproduce the status quo unequal relation between NES and NNES teachers by making all parties involved believe in the artificial sociocultural arrangements that favor NES teachers as legitimate. The findings direct our attention to the importance of critical teacher education that will enable future TESOL professionals to engage in critical reflection on diverse issues and envision transformative change. The findings, in particular, point to the need for language support for NNES teachers in TESOL teacher education.

• 기본간호학회지
• /
• 제25권1호
• /
• pp.1-10
• /
• 2018

Purpose: The purpose of this study was to investigate effects of leadership, critical thinking disposition, and professional self-conception of nurse on happiness in nursing students. Methods: Data ware collected from 160 nursing students from March to May 2015, using self reported questionnaire. Descriptive statistics, t-test, ANOVA, correlation analysis and multiple regression were used to analyze the collected data. Results: Happiness in nursing students was correlated with leadership (r=.68, p<.001), critical thinking disposition (r=.36, p<.001) and professional self-conception of nurse (r=.57, p<.001). Factors significantly influencing happiness in nursing students were leadership (${\beta}=.48$, p<.001), professional self-conception of nurse (${\beta}=.17$, p=.032) and life satisfaction (${\beta}=.18$, p=.003), with a total explanatory power of 53.0%. Conclusion: The results of this study showed that leadership, critical thinking disposition, and professional self-conception of nurse should be promoted to increase happiness of nursing students.

• 융합보안논문지
• /
• 제13권2호
• /
• pp.175-183
• /
• 2013

본 연구는 전문대학 신입생의 비판적 사고성향과 문제해결과정의 정도를 파악한 후 이들 간의 상관성과 문제해결과정에 미치는 영향을 파악하고자 수행하였다. 연구대상은 전문대학에 재학 중인 1학년 215명이었고 자료수집은 구조화된 설문지를 이용하여 2012년 11월 20일에서 12월 5일까지 수집하였고 SPSS 18.0으로 분석하였다. 연구결과, 전문대학 신입생의 비판적 사고성향은 연령, 대인관계에서 유의한 차이가 있었고, 문제해결과정은 연령, 대인관계, 전공만족도에서 유의한 차이가 있었다. 전문대학 신입생의 비판적 사고성향과 문제해결과정간의 관계는 통계적으로 유의한 양의 상관관계(r=.605, P<.001)를 나타냈다. 전문대학 신입생의 문제해결과정에 영향을 미치는 요인은 비판적 사고성향과 전공 만족도로 문제해결과정을 38% 설명하였다. 본 연구는 전문대학생의 비판적 사고성향이 문제해결에 미치는 영향에 대한 실증연구를 표준적인 방법론에 의거 체계적으로 수행하여 비판적 사고성향과 전공만족도를 높일 수 있는 합리적인 교수학습 전략 및 교육과정 개발 방향을 제시하였다는 점에서 그 의의를 찾을 수 있다.

• 한국농공학회논문집
• /
• 제65권4호
• /
• pp.25-32
• /
• 2023

KDS (Korean Design Standard) for agricultural drainage is a planning standard that helps determine the appropriate capacity and type of drainage facilities. The objective of this study was to analyze the inundation of the agricultural basin considering the current design standard and the critical rainfall duration. This study used the rainfall durations of 1-48 hour, and the time distribution method with the Chicago and the modified Huff model. For the runoff model, the NRCS (Natural Resources Conservation Service) unit hydrograph method was applied, and the inundation depth and duration were analyzed using area-elevation data. From the inundation analysis using the modified Huff method with different rainfall durations, 4 hours showed the largest peak discharge, and 11 hours showed the largest inundation depth. From the comparison analysis with the current method (Chicago method with a duration of 48 hours) and the modified Huff method applying critical rainfall duration, the current method showed less peak discharge and lower inundation depth compared to the modified Huff method. From the simulation of changing values of drainage rate, the duration of 11 hours showed larger inundation depth and duration compared to the duration of 4 hours. Accordingly, the modified Huff method with the critical rainfall duration would likely be a safer design than the current method. Also, a process of choosing a design hydrograph considering the inundation depth and duration is needed to apply the critical rainfall duration. This study is expected to be helpful for the theoretical basis of the agricultural drainage design standards.

• 중환자간호학회지
• /
• 제17권1호
• /
• pp.1-16
• /
• 2024

Purpose : This study aimed to explore and describe intensive care unit (ICU) nurses' experience of clinical adaptation. Methods : The participants were 14 ICU nurses with more than two years of working experience in the ICU. Data were collected through in-depth individual interviews conducted between July and October 2021. Theoretical sampling was used to the point of theoretical saturation. Data were analyzed using the Strauss and Corbin method. Results : A total of 79 concepts, 37 subcategories, and 16 categories were identified through open coding. Axial coding based on the paradigm model revealed that the central phenomenon was "The harsh adversity faced in the nursing field where life and death are determined" and the core category was "Enduring the adversity of caring for critically ill patients and achieving self-realization." ICU nurses' clinical adaptation process was explained in five phases: "confrontation period," "turbulent period," "seeking period," "struggling period," and "stabilized period." The five phases that affect interventional conditions were "Support from reliable people," "Recognition of administrative and financial support." Conclusion : This study provided novel insights for a comprehensive understanding of ICU nurses' clinical adaptation processes. Furthermore, the findings are expected to be used as basic data to develop multifaceted strategies to help ICU nurses' adaptation to critical care.

• 대한간호
• /
• 제23권2호통권125호
• /
• pp.49-68
• /
• 1984

This study was tried with the purpose of using this one as the basic data of future researches through content analysis according to structure of theory and criteria for evaluating theories, which is based on Hardy''s standard. As a result, there were a l