• Earthquakes and Structures
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• 제17권3호
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• pp.245-256
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• 2019

An experimental study was conducted to evaluate the dynamic behavior of a free-standing frame equipped with a movable base system using cast iron and mortar as the bearing materials. The preliminary friction test indicated that a graphite layer developed on the interface and exhibited stable friction behavior. The friction coefficient ranged from 0.33 to 0.36 when the applied normal compression stress ranged from 2.6 to 5.2 MPa. The effect of the variation of normal compression stress would be small. Shaking table tests on the free-standing frame showed that rock, slide, and rock-slide responses occurred. The cumulative slide distance reached 381 mm under JMA Kobe wave excitation; however, only a few cyclic slides occurred at the same locations along the moving track. Most surfaces sustained single slides. Similar results can be observed in other shaking conditions. The insufficient cyclic sliding and significant rocking resulted in a few graphite layers on the mortar surfaces. Friction coefficients were generally similar to those obtained in the preliminary friction tests; however, the values fluctuated when the rocking became significant. The collisions due to rocking caused strong horizontal acceleration responses and resulted in high friction coefficient. In addition, the strong horizontal acceleration responses caused by the collisions made the freestanding specimen unable to reduce the input horizontal acceleration notably, even when slippage occurred. Compared with the counterpart fixed-base specimen, the specimen equipped with the iron-mortar base could reduce the horizontal acceleration amplification response and the structural deformation, whereas the vertical acceleration response was doubled due to collisions from rocking.

• Earthquakes and Structures
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• 제26권4호
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• pp.261-267
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• 2024

With the increase in the exploitation depth of offshore oil and gas, it is possible to control the global buckling of deep-sea pipelines by the snake lay method. Previous studies mainly focused on the analysis of critical buckling force and critical temperature of pipelines under the snake-like laying method, and pipelines often suffer structural failure due to seismic disasters during operation. Therefore, seismic action is a necessary factor in the design and analysis of submarine pipelines. In this paper, the seismic action of steel pipes in the operation stage after global buckling has occurred under the active control method is analyzed. Firstly, we have established a simplified finite element model for the entire process cycle and found that this modeling method is accurate and efficient, solving the problem of difficult convergence of seismic wave and soil coupling in previous solid analysis, and improving the efficiency of calculations. Secondly, through parameter analysis, it was found that under seismic action, the pipe diameter mainly affects the stress amplitude of the pipeline. When the pipe wall thickness increases from 0.05 m to 0.09 m, the critical buckling force increases by 150%, and the maximum axial stress decreases by 56%. In the pipe soil interaction, the greater the soil viscosity, the greater the pipe soil interaction force, the greater the soil constraint on the pipeline, and the safer the pipeline. Finally, the pipeline failure determination formula was obtained through dimensionless analysis and verified, and it was found that the formula was accurate.

• 보건행정학회지
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• 제34권2호
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• pp.129-140
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• 2024

연구배경: 트라우마가 초래한 정신건강 문제는 사건의 특성에 따라 다르게 나타날 수 있다. 특히 성적 외상사건 경험자는 다른 유형의 외상사건을 경험한 사람들보다 정신건강 결과가 부정적이라고 알려져 있을 뿐만 아니라, 디지털 성범죄 등 성적 사건에 노출될 수 있는 새로운 형태의 위협이 커지고 있다. 이 연구는 성적 트라우마 사건을 중심으로 트라우마 사건의 유형이 정신건강의 차이를 유발하는지 확인하고, 자살생각과 잠재적 post-traumatic stress disorder (PTSD) 위험수준에 영향을 미치는 요인을 확인하고자 하였다. 방법: 전국 20대부터 50대까지 성인을 대상으로 실시한 온라인 설문조사를 토대로, 경험한 트라우마 사건의 유형에 따라 분석대상자를 구분하였다(성적 트라우마 경험자, 비성적 트라우마 경험자). 성적 트라우마 사건 경험 여부를 제외하고 정신건강(자살생각, 잠재적 PTSD 위험수준)에 영향을 미칠 수 있는 인구사회학적 요인(성, 연령, 주관적 경제수준, 결혼상태)과 회복 보호요인(사회적 지지, 회복 가능성 인지, 아동기 보호경험)을 공변량으로 propensity score matching (PSM)을 실시하였다. 이후 정신건강에 영향을 미치는 요인을 확인하기 위해 이분형 로지스틱 회귀분석을 하였다. 결과: PSM 후에도 성적 트라우마 경험자는 비성적 트라우마 경험자보다 자살생각과 잠재적 PTSD 위험수준이 부정적이었다. 이분형 로지스틱 회귀분석 결과, 성적 트라우마 경험자는 비성적 트라우마 경험자보다 자살생각이 1.9배(odds ratio [OR], 1.911), 잠재적 PTSD 위험수준은 2.5배(OR, 2.472) 높았다. 또한 트라우마 회복 인식, 사회적 지지, 아동기 보호 경험과 같은 회복 보호요인이 부정적일수록 자살생각과 잠재적 PTSD 위험수준의 가능성이 높아졌다. 결론: 이 연구는 성적 트라우마 경험에 대한 이해와 지원의 중요성을 강조하고, 성적 트라우마 경험자의 자살생각과 잠재적 PTSD 위험을 완화하고 회복을 돕기 위해 회복 보호요인을 촉진하는 전략의 필요성을 시사한다.

• 한국직업건강간호학회지
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• 제29권3호
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• pp.208-218
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• 2020

Purpose: Nurses' job satisfaction corresponds with personal intrinsic value, and is the strongest predicting turnover and job retention intention. This study identified the effectiveness of job satisfaction interventions related to reinforcing intrinsic motivation (JSI-RIM) for hospital nurses. Methods: This study used four core non-Korean databases (Cochrane Library, CHINHL, EMBASE, PubMed), and five Korean databases to search for RCT and NRCT articles published in English and Korean from inception to June 2019. Meta-analysis was performed using the RevMan 5.3.5 program. Results: Thirteen studies featuring 645 hospital nurses were selected for final analysis. A significant large effect was noted on self-efficacy. The effect size on perceived stress and job satisfaction were moderate; however, the effect on resilience outcomes was not significant. Conclusion: This study generated scientific evidence that would facilitate efficient job adaptation for nurses. Additionally, intrinsic factors, including job identity and meaning of work, need to be included in JSI-RIM.

• 임상간호연구
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• 제22권1호
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• pp.88-98
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• 2016

Purpose: The purpose of this study was to construct and test a structural equation model of burnout of the critical care nurses based on the job demand-resource model. Methods: A structured questionnaire was completed by 414 critical care nurses. The relationships between concepts of job stress, empathic ability, resilience, job satisfaction, compassion fatigue and burnout were analyzed. Using SPSS WIN 22.0 and AMOS 22.0 programs, the direct and indirect effects of factors affecting burnout among critical care nurses were calculated and modelled. Results: The modified model was yielded as follows: Chi-square= 216.59, GFI= .93, AGFI= .89, NFI= .90, CFI= .93, RMSEA= .07, SRMR= .06 and showed good fit indices. Job satisfaction and compassion fatigue had mediation effects between other three exogenous variables and burnout. Conclusion: The major findings of this study indicate that it is important to develop a support program for critical care nurse in order to improve their job satisfaction and ameliorate their compassion fatigue.

• Weed & Turfgrass Science
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• 제4권4호
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• pp.338-347
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• 2015

Reinforcement cells are used to aid grass growth and taken together, this serves to extend greenery beyond the conventional spaces of lawns, tree pits, gardens, and parks, and is advantageous to urban cities since space for greening is often limited. Drought has variable effects on plant life and the resilience of turf to drought resistance also varies with species. Changes in photosynthetic ability were more pronounced for media rather than grass species. The media of sand without organic matter was found to be least suited for drought resistance. Normalized difference vegetation index (NDVI) and digital image analysis (DIA) data were generally in favour of Zoysia species as oppose to A. compressus. In A. compressus, selective traits such as, a more extensive root system and lower specific leaf area (SLA) were not an underlying factor that assisted this grass with enhanced drought resistance. Generally, WUE was found to be strongly related to plant characterises such as overall biomass, photosynthetic features as well as the lushness indexes, and specific leaf area. This study found a strong relationship between WUE and a suite of plant characteristics. These traits should serve as useful selection criteria for species with the ability to resist water stress.

• 한국보건간호학회지
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• 제33권3호
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• pp.409-419
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• 2019

Purpose: Factors related to the major satisfaction of nursing students were systematically searched and quantitatively synthesized. Methods: Meta-analysis was conducted upon 47 articles in Korean master and doctorate degree dissertations and academic journals. Meta-analysis of major satisfaction-related variables was conducted using Comprehensive Meta-Analysis (CMA) 2.0 program. The effect size of the related variables was analyzed by converting the statistic r value to Fisher's Z. Results: The overall average effect size of major satisfaction was the largest effect size (ES=.49), followed by cognitive factors (ES=.58), affective factors (ES=.45), and psychomotor factors (ES=.31). The cognitive factors were in the order nursing professionalism(ES=.70), nurse's image (ES=.65), and critical thinking disposition (ES=.36). The affective factors were self-esteem (ES=.59), emotional intelligence (ES=.55), career identity (ES=.49), self-efficacy (ES=.48), college adjustment (ES=.45), practice satisfaction (ES=.45), resilience (ES=.42), (ES=.40), grit (ES=.34), and stress (ES=.26). The psychomotor factors were clinical performance ability (ES=.38) and career search behavior (ES=.31). Conclusion: The results of this study are valuable when giving consideration to the variables related to nursing students' major satisfaction, for developing a strategic model to enhance the satisfaction of nursing students.

• 가정∙방문간호학회지
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• 제28권3호
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• pp.243-255
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• 2021

Purpose: This study was conducted to explore research trends on hospital nurses' happiness. Methods: Studies published from January 1, 2000 to December 31, 2020 were searched. At the first search, 1,898 articles were extracted from academic databases. Twenty-eight articles were used in the systematic review, and 20 included meta-analysis. Results: There were 38 variables explored in relation to nurses' happiness. The variables with the highest meta-analysis value were resilience, positive psychological capabilities, quality of nursing work life, and perceived stress on nursing performance measurement. Among the areas classified based on the nurses' happiness theoretical framework, personal factors (r=.60) and work environment factors (r=.51) showed high meta-correlation values. Conclusion: The relationship between the hospital nurses' happiness and work-related factor in various dimensions has been confirmed. Considering variables related to hospital nurses' happiness in the future, various programs at the individual level and organizational level should be developed.

• Steel and Composite Structures
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• 제32권2호
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• pp.265-279
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• 2019

The self-centering capacity and energy dissipation performance have been recognized critically for increasing the seismic performance of structures. This paper presents an innovative steel moment frame with self-centering steel reinforced concrete (SRC) wall panel incorporating replaceable energy dissipation devices (SF-SCWD). The self-centering mechanism and energy dissipation mechanism of the structure were validated by cyclic tests. The earthquake resilience of wall panel has the ability to limit structural damage and residual drift, while the energy dissipation devices located at wall toes are used to dissipate energy and reduce the seismic response. The oriented post-tensioned strands provide additional overturning force resistance and help to reduce residual drift. The main parameters were studied by numerical analysis to understand the complex structural behavior of this new system, such as initial stress of post-tensioning strands, yield strength of damper plates and height-width ratio of the wall panel. The static push-over analysis was conducted to investigate the failure process of the SF-SCWD. Moreover, nonlinear time history analysis of the 6-story frame was carried out, which confirmed the availability of the proposed structures in permanent drift mitigation.

• Safety and Health at Work
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• 제14권1호
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• pp.1-9
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• 2023

Background: Firefighting involves exposure of firefighters to risks related to this activity, serious injuries, and occupational diseases are recorded. There are other consequences such as thermal and emotional stress. This systematic review is proposed in order to analyze the risks and consequences faced by these workers and thus provide elements to improve safety management systems in institutions. Method: A descriptive observational study of systematic literature review on the risks and consequences of exposure to firefighters' activity was proposed, and the information was analyzed and described based on the available data and according to the variables determined. Results: The studies showed data on mechanical, physical, chemical, psychosocial risks, workers' perception and resilience, and epidemiological data. Information related to firefighters' activity on falls and slips, exposure to noise, and high concentrations of carbon monoxide is detailed. In addition, the relationship between burnout, cognitive, and physical fatigue as adverse effects on health and performance is mentioned. Conclusions: Among the preventive measures, the use of personal protective equipment is suggested, incorporation in prevention programs of information on exposure to risk factors, as well as the implementation of models that can predict the perception of workers, additionally, the generation of management systems with safety climate models for fire departments.