• 폴리머
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• 제37권1호
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• pp.47-51
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• 2013

본 연구에서는 알루미나 나노섬유의 함량을 20에서 100 phr까지 달리하여 알루미나 나노섬유와 분말이 첨가된 에폭시 복합재료의 열전도도 및 파괴인성에 미치는 영향에 대해서 살펴보았다. 열전도도는 열전도도분석기로 측정하였고, 파괴인성은 임계응력세기인자($K_{IC}$) 측정을 통하여 고찰하였다. 모폴로지는 주사전자현미경(SEM)으로 관찰하였다. 실험결과, 알루미나 나노섬유의 함량이 증가함에 따라 열전도도가 향상됨을 확인할 수 있었으며, 알루미나 나노섬유의 함량이 열전도도를 결정하는 중요한 요소임을 알 수 있었다. $K_{IC}$ 값도 알루미나 나노섬유의 함량이 증가할수록 큰 값을 가지는 것을 확인할 수 있었으나 40 phr 이상에서는 오히려 감소하였다. 이는 과량의 알루미나 나노섬유가 에폭시 내에서 서로 뭉침으로 인하여 $K_{IC}$ 값을 감소시킨 것으로 판단된다.

• 폴리머
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• 제37권4호
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• pp.449-454
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• 2013

본 연구에서는 무전해 니켈도금에 따른 탄소나노튜브의 표면특성변화가 알루미나강화 에폭시 복합재료의 열전도도 및 파괴인성에 미치는 영향에 대하여 살펴보았다. 무전해 니켈도금된 탄소나노튜브의 표면특성은 주사전자현미경(SEM), X-선 광전자분광기(XPS), X-선 회절분석(XRD)을 통하여 알아보았다. 열전도도는 열전도율 측정 시스템으로 측정하였고, 파괴인성은 만능시험기(UTM)를 이용한 임계응력세기인자($K_{IC}$)를 측정하여 분석하였다. 실험결과, 무전해 니켈도금은 탄소나노튜브의 표면특성의 변화를 가져오며, 니켈도금된 MWCNTs(Ni-MWCNTs)가 들어있는 경우 미처리 MWCNTs와 비교하여 우수한 열전도도 및 파괴인성을 보였다. 이는 Ni-MWCNTs와 에폭시수지와의 분자간 상호작용의 향상 때문이라 판단된다.

• Journal of Welding and Joining
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• 제27권6호
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• pp.68-73
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• 2009

Recently, as titanium and titanium alloys are being increasingly used in wide areas, there are on-going researches to obtain high quality weld zone. In particular, growing interest is being drawn to laser welding, which involves low heat input and large aspect ratio in various welding processes and can facilitate shield in atmospheric condition compared with electron beam welding. The first report covered the analysis of embrittlement by the bead color of weld zone through quantitative analysis of oxygen and nitrogen and measurement of hardness as basic experiment to apply laser welding to titanium. Results indicated that the element that affect embrittlement the most was nitrogen, and as embrittlement and oxygenation go on, bead color changed to silver, gold, brown, blue and gray. This study performed butt welding of pure titanium and STS304 by using 1kW CW Nd:YAG laser, and to find out basic physical properties, evaluated welding performance by laser output, welding speed, root gap and misalignment etc, and examined mechanical properties through tensile stress and Erichsen test. The reason particles of pure titanium welded metal and HAZ are greater than STS304 is because they are pure metal and do not include many impure elements that work as nuclei in case of resolidification, thus becoming coarse columnar crystals eventually. In addition, the reason STS304 requires more energy during welding than pure titanium is because the particle size of base metal is smaller.

• Wind and Structures
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• 제35권1호
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• pp.55-66
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• 2022

Tall buildings are often subjected to steady and unsteady forces due to external wind flows. Measurement and mitigation of these forces becomes critical to structural design in engineering applications. Over the last few decades, many approaches such as modification of the external geometry of structures have been investigated to mitigate wind-induced load. One such proven geometric modification involved the rounding of sharp corners. In this work, we systematically analyze the impact of rounded corner radii on the reducing the flow-induced loading on a square cylinder. We perform 3-Dimensional (3D) simulations for high Reynolds number flows (Re=1 × 105) which are more likely to be encountered in practical applications. An Improved Delayed Detached Eddy Simulation (IDDES) method capable of capturing flow accurately at large Reynolds numbers is employed in this study. The IDDES formulation uses a k-ω Shear Stress Transport (SST) model for near-wall modelling that prevents mesh-induced separation of the boundary layer. The effects of these corner modifications are analyzed in terms of the resulting variations in the mean and fluctuating components of the aerodynamic forces compared to a square cylinder with no geometric changes. Plots of the angular distribution of the mean and fluctuating coefficient of pressure along the square cylinder's surface illustrate the effects of corner modifications on the different parts of the cylinder. The windward corner's separation angle was observed to decrease with an increase in radius, resulting in a narrower and longer recirculation region. Furthermore, with an increase in radius, a reduction in the fluctuating lift, mean drag, and fluctuating drag coefficients has been observed.

• 한국직업건강간호학회지
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• 제11권2호
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• pp.91-107
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• 2002

In order to evaluate the factors related to therapeutic compliance of hypertensive patients in small and medium scale industry, the questionnaire survey and the blood pressure measurement were performed on 138 hypertensive patients who were reported to have C or $D_2$ result of hypertension at the workers' periodic health examination from March to November 2001. The contents of questionnaire included the informations of factors related to therapeutic compliance of hypertensive patients such as, age, sex, marital status, income, education levels, scale, occupation, work duration, smoking and drinking habits, exercise, family history, stress and A type personality, employer's concern, organizational culture, health status, awareness, knowledge and attitude toward the needs of hypertension treatment, and experience of health education. The results of the study were as follows: 1. The proportion of those who were compliant to the treatment of hypertension was 41.3% of subjects. Among small scale industry less than 50 employees, the rate of therapeutic compliance group was 27.5% and therapeutic noncompliance group was 72.5%. Among medium scale industry more than 50 employees, the rate of therapeutic compliance group was 60.3% and therapeutic noncompliance group was 39.7%. 2. Among therapeutic noncompliance group, 95.1% of patients were aware of the fact that workers have hypertension, and 77.8% of patients got 6-10 marks of hypertension related knowledge. For health education, 27.2% were experienced and 34.6% said no intention to participate. And for hypertension treatment, 9.9% said no need to get the treatment and 44.4% said have no idea whether get treatment or not. 3. The significant factors related to therapeutic compliance of hypertensive patients in small scale industry were work duration, A type personality(anger), health status, attitude toward the needs of hypertension treatment, and experience of health education. 4. The significant factors related to therapeutic compliance of hypertensive patients in medium scale industry were age, occupation, subjective symptom, attitude toward the needs of hypertension treatment, and experience of health education. In consideration of above findings, it was suggested that in order to improve the therapeutic compliance in small and medium scale industry hypertensives, it be necessary to change attitude, perception, knowledge and treatment of hypertension by various methods such as effective health education and individually consulting programs by occupational health professional.

• 한국산업보건학회지
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• 제32권1호
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• pp.64-77
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• 2022

Objectives: The purpose of this study is to objectify the level of case management performance and the factors influencing performance, to improve the case management performance at the Korea Worker's Compensation & Welfare Service (KWCWS) on the basis of the recognition of the objective realities of case management by job coordinators at the KWCWS, to develop a model of case management fit for the KWCWS, and to provide a basis for establishing guidelines for standardized case management. Methods: A total of 156 questionnaires were distributed to job coordinators at the KWCWS's headquarters, six regional headquarters, and 55 branches. One hundred forty-one questionnaires were collected and 126 were analyzed statistically using SPSS 21.0. Factor analysis and reliability analysis were conducted to verify the validity and reliability of the main measurement items in the research model. Frequency analysis was conducted for general characteristics of survey subjects. Frequency analysis or descriptive statistics were conducted to identify the level of independent variables (case manager's individual variables, job variables, institutional and organizational variables). Dependent variables (case management performance) and the degree of correlation were analyzed through correlation analysis between research variables. Multiple regression analysis and hierarchical regression analysis were conducted to examine the effect of independent variables on case management performance. Results: The results of the study showed that the level of overall performance in the five stages of case management was ordinary, with an average level of 3.45 on a 5-point scale. Levels of performance by step were institutional approach and intake (3.69), assessment (3.63), goal setting and intervention planning (3.46), implementation of intervention plan (3.32), and evaluation and termination (3.20), in that order. The explanatory power of case management performance (overall) by case managers with the KWCWS was case manager's institutional and organizational variables, job variables, and individual variables, in that order. At each stage of case management, the explanatory power of a case manager's institutional and organizational variables was found to be the greatest. The model changes at each stage of case management assume similar aspects statistically. In hierarchical regression analysis, it was institutional support that had a significant effect on case management performance (overall), and institutional support had the greatest effect. The results of multiple regression analysis in which all variables are input simultaneously showed that institutional support and expertise as well as self-efficacy had a positive effect. However, case management work experience, expertise (technology), and autonomy were found to have a negative effect during the stage of case management performance. Conclusions: As a result of the study, it was confirmed that raising the case manager's expertise and support from the institution and organization are important factors to improve the level of case management performance. The research also derived practical ways of reinforcement of case manager capacity, institutional and organizational support, operation of rehabilitation-case management teams, and occupational health-related aspects.

• Asia pacific journal of information systems
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• 제18권1호
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• pp.53-77
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• 2008

In recent years, although numbers of corporations are bringing in PMO, they seem to be indifferent to PMO performance measurement. This demonstrates that there are also other reasons beside performance measurement of information systems (IS) project being ambiguous by introducing PMO; the lack of acknowledging the concrete function of PMO, and the scarcity of empirical study about the effect of PMO on the project members and project performance. In this sense, this study is aimed at proposing a new research model in which project success factors (i.e., standardization, management advocacy, and staff expertise) affect PMO capability (i.e., knowledge management, resources management, and problem solving competency) positively, leading to project performance (i.e., task outcomes, psychological outcomes, and organizational outcomes) eventually. To empirically test the research model, data are surveyed from PMO department and IS department. To prove the validity of the proposed research model, PLS analysis is applied with valid 132 questionnaires. By employing PLS technique, the measurement reliability and validity of research variables are tested and the path analysis is conducted to do the hypothesis testing. The path analysis results can be organized into 7 ways in large scale. First, standardization of project success factors has a positive association with knowledge management, resources management, and problem solving competency of PMO capabilities. The findings of this result indicate that the multiple or single project management should satisfy standardization in order to operate an effective PMO. Second, management advocacy of project success factors has a positive association with knowledge management, resources management, and problem solving competency. Management advocacy refers to the willingness of management to provide the required resources and authority for project success. There is agreement among researchers regarding the importance of management advocacy for favorable PMO capability. Third, staff expertise of project success factors has a positive association with knowledge management, resources management, and problem solving competency. The findings of this result indicate that the formation of an exceptional consultant or members with a proficient knowledge for staff expertise of project member is the key factor to elevate the PMO capability. Past research suggests that experience and knowledge and the resultant familiarity with the problem faced can be an important determinant of PMO capability. A capable project with appropriate staff expertise means that it enjoys a diversity of abilities and experiences. Fourth, knowledge management competency of PMO capabilities has a positive impact on psychological outcomes but has no direct effect on task outcomes and organizational outcomes. In domestic case of S. Korea, PMO was finally introduced to many other corporations in 2005 though it started bringing in 2000. Therefore, it had neither a significant impact on the task outcomes nor organizational outcomes by lacking the contents and the infrastructure of the knowledge management because the knowledge consolidation and management period of PMO is comparatively shorter by terms than other foreign nations. Fifth, resources management competency of PMO capabilities has a positive association with task outcomes, psychological outcomes, and organizational outcomes. In addition, problem solving competency of PMO capabilities has a positive association with task outcomes, psychological outcomes, and organizational outcomes. Therefore, the findings of this results stress that PMO capabilities has a positive impact on project performance. Sixth, according to the path analysis of the hypothesis, which suggested in this research, problem solving competency is the PMO capability which is the key success factor for task, psychological, and organizational outcomes as an integrated performance model. Further, the analysis reveals that problem solving competency is an important factor for integrated performance model. The finding is in line with past IS research, which affirms that the work of IS projects is essentially a problem solving endeavor. Seventh, in the path analysis of the hypothesis in this research, the path of the management advocacy $\rightarrow$ problem solving competency $\rightarrow$ organizational outcomes appears to be the most important and strongest path. In brief, the finding of this study suggests that project success factors influence PMO capability positively, and project performance as well. From the results, it can be concluded that PMO helped great improve the project success rate and project performance. This study advances research on PMO capability in three important aspects. First, the findings of our study have implications for IS theory and future research. Our study contributes to IS theory by synthesizing concepts from PMO research and project management research with those in IS research. We proposed and tested PMO capability of IS projects and the findings of our investigation provided some preliminary answers to some of the questions raised. Secondly, this thesis does not only help depicting the concept of IT governance but also approaches empirically. It makes a gradual approach to the main content, step by step, in contrary of simple standard, scholastic way of thinking. Finally, we argued that this task-oriented(technical) view is not sufficient to adequately conceptualize IS project performance. Hence, we applied that the research on organization teams, which provides a flip viewpoint to that of project management research in that it gives more weight for psychological outcomes of organizational work groups, can be very helpful in reconceptualizing the IS project performance construct. The limitations of this study are also discussed to provide research directions for future research.

• 한국사회복지학
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• 제61권2호
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• pp.325-348
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• 2009

암은 우리나라의 사망원인 1위로, 환자뿐 아니라 가족의 삶에도 큰 영향을 미친다. 특히, 돌봄책임을 맡고 있는 가족원의 삶의 질은 사회적 지지, 돌봄 부담에 대한 평가, 재평가에 의해 영향을 받는다. 암환자 가족의 삶의 질을 향상시키기 위해서는 이들 요인들 간의 유기적인 관계를 밝혀 사회복지 실천 방법을 발전시킬 필요가 있다. 본 연구에서는 국립암센터를 이용하는 암환자 가족 295명의 사회적 지지, 돌봄 부담감, 내적 성장, 삶의 질을 파악하고, 이들 변수간의 관계를 구조방정식모형을 통해 검증하였다. 연구결과 첫째, 연구모형의 적합성을 검증하였을 때 적합도 지수가 CFI(.951), TLI(.940), RMSEA(.062)으로 좋은 적합도를 보였다. 둘째, 직접효과에 대한 검증결과 사회적 지지의 돌봄 부담감, 내적 성장에 대한 직접효과, 돌봄 부담감의 내적 성장, 삶의 질에 대한 직접효과, 내적 성장의 정신적 삶의 질에 대한 직접효과가 통계적으로 유의하였다. 셋째, 돌봄 부담감, 내적 성장의 매개효과에 대한 검증 결과, 사회적 지지가 삶의 질에 미치는 영향에 대한 돌봄 부담감의 매개효과, 사회적 지지와 돌봄 부담감이 정신적 삶의 질에 미치는 영향에 대한 내적 성장의 매개효과가 통계적으로 유의하였다. 이러한 결과에 따라 암환자 가족의 삶의 질에 영향을 미치는 사회적 지지, 돌봄부담, 내적성장간의 관계에 대하여 논의하고 사회복지 실천 및 연구를 위한 함의를 제언하였다.

• 대한인간공학회지
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• 제36권1호
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• pp.23-36
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• 2017

Objective: This paper presents a study to evaluate the WBGT index for assessing the effects of a wide range of outdoor weather conditions on human responses. Background: The Wet Bulb Globe Temperature (WBGT) index was firstly developed for the assessment of hot outdoor conditions. It is a recognised index that is used world-wide. It may be useful over a range of outdoor conditions and not just for hot climates. Method: Four group experiments, involving people performing a light stepping activity, were conducted to determine human responses to outside conditions in the U.K. They were conducted in September 2007 (autumn), December 2007 (winter), March 2008 (spring) and June 2008 (summer). Environmental measurements included WBGT, air temperature, radiant temperature (including solar load), humidity and wind speed all measured at 1.2m above the ground, as well as weather data measured by a standard weather station at 3m to 4m above the ground. Participants' physiological and subjective responses were measured. When the overall results of the four seasons are considered, WBGT provided a strong prediction of physiological responses as well as subjective responses if aural temperature, heart rate and sweat production were measured. Results: WBGT is appropriate to predict thermal strain on a large group of ordinary people in moderate conditions. Consideration should be given to include the WBGT index in warning systems for a wide range of weather conditions. However, the WBGT overestimated physiological responses of subjects. In addition, tenfold Borg's RPE was significantly different with heart rate measured for the four conditions except autumn (p<0.05). Physiological and subjective responses over 60 minutes consistently showed a similar tendency in the relationships with the $WBGT_{head}$ and $WBGT_{abdomen}$. Conclusion: It was found that either $WBGT_{head}$ or $WBGT_{abdomen}$ could be measured if a measurement should be conducted at only one height. The relationship between the WBGT values and weather station data was also investigated. There was a significant relationship between WBGT values at the position of a person and weather station data. For UK daytime weather conditions ranging from an average air temperature of $6^{\circ}C$ to $21^{\circ}C$ with mean radiant temperatures of up to $57^{\circ}C$, the WBGT index could be used as a simple thermal index to indicate the effects of weather on people. Application: The result of evaluation of WBGT might help to develop the smart clothing for workers in industrial sites and improve the work environment in terms of considering workers' wellness.

• Journal of the Korean Data and Information Science Society
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• 제27권6호
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• pp.1609-1619
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• 2016

본 연구는 한국형 웰니스 생활양식 측정도구의 구성타당도와 신뢰도를 확인하기 위한 도구개발 연구이다. 간호대학생 345명이 99문항의 WEL (wellness evaluation of lifestyle)을 작성하였고, SPSS WIN 22.0와 AMOS 18.0을 이용한 탐색적 요인분석과 확인적 요인분석을 통해 측정도구의 구성타당도를 검증하였다. 최종 한국형 웰니스 생활양식 측정도구는 71문항, 14개 하위척도로 구성되었다. 각 하위척도는 4개의 요인구조를 가지는 것으로 확인되었다: 본질적 자기, 사회적 자기, 신체적 자기, 적응적 자기, 모델의 적합도는 ${\chi}^2=225.12$, p<.001, CMIN/DF=3.17, RMSEA=.08, NFI=.87, IFI=.91, CFI=.91로 나타났다. 도구의 집중타당도를 평가한 결과 기각비 (C.R.)는 2.95~16.84로였고, 표준분산추출 (AVE)도 .61~.69로 수용 가능하였다. 하위척도의 내적 일치도 Cronbach's ${\alpha}$는 .55~.87이었다. 본 연구를 통해 한국형 웰니스 생활양식 측정도구가 한국인의 웰니스를 다차원적으로 측정하기에 타당하고 신뢰성있는 도구임을 확인하였다.