관통구를 갖는 판구조물의 강도평가 방법에 관한 연구

김을년,장준태 대한조선학회 2017 大韓造船學會 論文集 Vol.54 No.6

The purpose of this paper is to verify the structural integrity of a region with numerous penetration-holes in offshore structures such as semi-submersible rig and FPSO. In order to effectively check the yielding and buckling strength of plate members with penetration-holes, a screening analysis program was developed with the FE analysis tool to generate fine meshed model using the theoretical and analysis methods. When a hole is appeared in the plate structure members, the flow of stress is altered such that concentrations of stress form near the hole. Stress concentrations are of concern during both preliminary and detail design and need to be addressed from the perspectives of strength. To configure the geometrical shape, very fine meshed FE analysis is needed as the most accurate method. However, this method is practically impossible to apply for the strength verifications for all perforated plates. In this paper, screening analysis method was introduced to reduce analysis tasks prior to detailed FE analysis. This method is applied to not only the peak stress calculation combined stress concentration factor with nominal stress but also nominal equivalent stress calculation considering cutout effects. The areas investigated by very fine meshed analysis were to be chosen through screening analysis without any reinforcements for penetration-holes. If screening analysis results did not satisfy the acceptance criteria, direct FE analysis method as the 2nd step approach were applied with one of the coarse meshed model considering hole or with the very fine meshed model considering the hole shape and size. In order to effectively perform the local fine meshed analysis, automatic model generating program was developed based on the MSC/PATRAN which is pre-post FE analysis program. Buckling strength was also evaluated by Common Structure Rule (CSR) adopted by IACS as the stress obtained from very fine meshed FE analysis. Due to development of the screening analysis program and automatic FE modeling program, it was able to reduce the design periods and structural analysis costs.

위기상황 스트레스 해소 교육 프로그램 제작을 위한 소방공무원의 외상 후 스트레스 장애 분석

최혜경,김지희 한국자료분석학회 2009 Journal of the Korean Data Analysis Society Vol.11 No.4

The purpose of this study was focused on the posttraumatic stress disorder analysis in Korea fire officers for the critical incident stress debriefing program development. In order to obtain the purpose, following variables were used; 3 independent variables(work burden, stress, stress response), 1 intermediating variable(on-scene stress), and 1 dependent variable (physical symptoms). The respondents were 970 fire officers in Korea from March to December in 2007 by using questionnaires developed by the researchers. Data was analyzed by SPSS 14.0 and AMOS 7.0 programs. Data cleaning was done for the exact data input. For the reliability and validity, exploratory factor analysis and Cronbach's alpha were analyzed. The general peculiarity of the respondents was shown by frequency analysis and descriptive analysis. In order to fulfill this study, the researchers proposed the hypothesis as follows : Work burden and stress will influence upon on-scene stress. Work burden, stress, on-scene stress and stress response will influence upon physical symptoms. Through the structured equation model analysis, the lower the level of work burden, stress and on-scene stress was, the lower the level of physical symptoms became. On the other hand, the higher the stress response was, the lower the level of physical symptoms became. 본 연구의 목적은 소방공무원이 현장에서 겪는 충격 스트레스로 발생하는 외상 후 스트레스장애 분석을 통해 위기상황 스트레스 해소 교육 프로그램 기초 자료를 제시하고자 하는 데 있다. 연구 목적을 달성하기 위하여 독립변인(업무부담감, 스트레스, 스트레스 대응) 3개, 매개변인(현장충격 스트레스) 1개, 종속변인(신체적 증상)으로 구성하여 영향력을 파악하였다. 본 연구 대상자는 전국 970명 소방공무원으로 2007년 3월부터 12월까지 구조화된 설문지를 이용하여 조사하였다. 자료분석은 SPSS 14.0과 AMOS 7.0 통계패키지를 사용하였으며, 정확한 코딩데이터의 입력확인을 위해 데이터클리닝(data cleaning) 작업을 실시하였다. 신뢰도와 타당도를 검정하기 위하여 탐색적 요인분석(exploratory factor analysis)과 Cronbach's 검증을 하였다. 연구대상의 일반적인 특성을 파악하기 위하여 빈도분석(frequency analysis)을 실시하였고, 각 요인에 대한 기술통계분석(descriptive analysis)을 실시하였다. 이 연구의 목적을 달성하기 위하여 설계한 연구가설은 선행 연구의 이론적 근거를 토대로 다음과 같이 설정하였다. 업무 부담감과 스트레스는 현장충격 스트레스에, 업무부담감, 스트레스, 현장충격스트레스, 스트레스대응은 신체적 증상에 영향을 줄 것이다. 가설검증을 위하여 구조방정식 모형분석을 실시한 결과, 업무부담감, 스트레스, 현장충격 스트레스가 낮고, 스트레스 대응이 높을 때 신체적 증상이 낮아지는 것으로 나타났다.

보일러 헤더 기동시의 탄성 크리프 해석에 의한 열응력 평가

신규인 ( Kyu In Shin ),윤기봉 ( Kee Bong Yoon ) 한국안전학회 2009 한국안전학회지 Vol.24 No.4

Thermal stress and elastic creeping stress analysis was conducted by finite element method to simulate start-up process of a boiler header of 500MW standard fossil power plant. Start-up temperature and operating pressure history were simplified from the real field data and they were used for the thermal stress analysis. Two kinds of thermal stress analysis were considered. In the first case only temperature increase was considered and in the second case both of temperature and operating pressure histories were considered. In the first analysis peak stress was occurred during the temperature increase from the room temperature. Hence cracking or fracture may occur at the temperature far below the operating maximum temperature. In the results of the second analysis von Mises stress appeared to be higher after the second temperature increase. This is due to internal pressure increase not due to the thermal stress. When the stress components of radial(r), hoop(θ) and longitudinal(z) stress were investigated, compression hoop stress was occurred at inner surface of the stub tube when the temperature increased from room temperature to elevated temperature. Then it was changed to tension hoop stress and increased because of the operating pressure. It was expected that frequent start-up and shut-down operations could cause thermal fatigue damage and cracking at the stub tube hole in the header. Elastic-creeping analysis was also carried out to investigate the stress relaxation due to creep and stabilized stress after considerable elapsed time. The results could be used for assessing the creep damage and the residual life of the boiler header during the long-term service.

직무스트레스 연구의 동향과 향후 방향

문형구,최병권,고욱 한국인사관리학회 2010 조직과 인사관리연구 Vol.34 No.3

In this study, we critically analyzed 56 studies on job stress published in academic journals in the field of human resource management and organizational behavior in Korea. Three analytical procedures were used to analyze, derive key features and limitation and provide implication for future researches regarding job stress in Korea. First is to general overview of the studies, hence we overally examined the number of studies per year, antecedents and consequence studies,study method. Second analysis was conducted in the aspects of a definition and dimensions, theory and type of study, and research method such as measures. Finally, we analyzed major findings of empirical studies, focused on antecedents,consequences and moderating variables of job stress. We discovered a few limitations through our analyses. First, related to definition and dimension, many researches did not clearly define the conceptual definition of job stress and job burnout. Also there is no discussion on the distinction and relation between these two terms, and hypotheses are verified without considering the subordinate dimensions of job stress and job exhaustion. A few studies did not use the exact terms of antecedents of job stress, job stress, and outcomes of job stress. Second, related to theory and research type, there were many studies that fragmentarily listed previous studies that used similar variables or hypotheses,without applying various theories related to job stress and job burnout. Many studies were repetitions of previous studies, using different models or theories or situations, and even those that verified new variables or models added new variables or models to existing research models. Also, there were studies that verified the relation between antecedents and outcomes of job stress without considering job stress itself. Thirdly, related to research method, while foreign studies are conducted on a wide range, including theory, term, measurement tools,sub-dimensions, qualitative analysis, and literature review, domestic researches are limited to empirical researches that conduct surveys based on foreign job stress theories and models, and therefore do not reflect the situations of Korea. Also a longitudinal study is needed in order to understand the cause and effect of job stress, but all domestic empirical studies use a cross-sectional analysis. Fourth,related to the level of analysis, there were no studies on groups or organizations and all empirical studies were limited to a personal level. There were various measurement tools for job stress, which made it difficult to combine the research results. Also a few studies neglected to provide basic information on measurement tools and measurement methods. Finally related to substantive analysis, many domestic studies on job stress were limited to examining the antecedents related to job or role. They were also more focused on examining antecedents and moderators of job stress rather than outcomes. Most researches presumed that job stress had a negative effect on the attitude and behavior of organization members,and there seemed to be a lack of consideration on whether this was true. Unlike foreign researches, domestic researches showed an insufficiency on personal and organizational methods on coping with job stress. In this study we suggest the following research directions for domestic researches on job stress. (1) Concept and dimension - A determination on the conceptual definition of job stress and job burnout, researches that examine the conceptual difference and relationship between job stress and job burnout,researches that consider the sub-dimensions of job stress and job burnout,researches that clarify the antecedents and outcomes that affect the sub-distentions of job stress and job burnout, researches that verify the effects of outcome variables, and a accurate use of job stress related terms. (2) Theory and research type - In-depth researches that apply various theories rel... 본 연구에서는 국내 주요 학술지에 발표된 총 56편의 직무스트레스 관련 연구들을 비판적으로 고찰하고 향후 연구방향을 제시하였다. 직무스트레스 연구에 대한 고찰은 전반적 현황 분석, 개념․이론․연구형태․연구방법 분석, 그리고 실질적 분석 등 세 가지 측면에서 이루어졌다. 국내 직무스트레스 연구의 주요 한계점들로 1) 전반적 현황 분석에서 직무 스트레스의 선행요인 중 주로 직무 및 역할 관련 요인들에 치중, 직무스트레스의 개념과 차원에 대한 개념적 연구의 부족, 종단면적 연구의 부족 등, 2) 개념․이론․연구형태․연구방법 분석에서는 직무스트레스에 대한 개념적 정의 부족, 직무스트레스와 직무소진간의 관계에 대한 논의의 미흡, 직무스트레스와 직무소진 하위차원에 대한 연구 부족, 직무스트레스 이론의 다양성 및 심층적 분석의 부족 등, 3) 실질적 분석에서는 직무스트레스의 조직 수준에서의 조절변수에 대한 연구 부족, 직무스트레스의 결과변수에 대한 연구 부족, 직무만족․조직몰입․이직의향 등 몇몇 결과변수에 치중 등을 지적하였다. 직무스트레스의 향후 연구방향으로, (1) 개념 측면에서 직무스트레스․직무소진의 개념적 정의의 명확화, 직무스트레스와 직무소진의 개념적 차이 및 이 두 개념간의 관계의 심층적규명, 직무스트레스와 직무소진의 하위차원에 따른 선행요인 및 결과변수의 규명과 관련한 연구의 필요성 등을 제시하였다. (2) 이론․연구형태와 관련해서는 다양한 이론을 활용한 직무스트레스 연구, 직무스트레스의 결과변수 및 매개변수 규명 연구의 활성화, 직무스트레스 연구 시에 직무스트레스 직접 측정의 필요성 등을 제시하였다. (3) 연구방법과 관련해서는 직무스트레스 측정도구의 지속적인 활용, 측정도구와 측정방법에 대한 충실한 정보 제공, 직무스트레스 연구방법의 다양화, 한국적 상황을 고려한 연구의 필요성 등을 제시하였다. 마지막으로 (4) 실증 연구와 관련해서는 다양한 직무스트레스의 선행요인 및 결과요인 규명 연구, 직무스트레스 대처 방식에 대한 연구, 조직 차원에서 직무스트레스의 완화 방안에 대한 연구, 연구의 표본 선정에의 주의 등을 제시하였다.

위탁선사 실습생의 승선실습 스트레스 요인 분석에 관한 연구

최경훈(Kyoung-Hoon CHOI),신호식(Ho-Sig SIN) 한국수산해양교육학회 2022 수산해양교육연구 Vol.34 No.2

The purpose of this study is to analyze the factors influencing the stress that the cadet feel during the on-board training by measuring the stress. The participants of this study were 129 cadets from Mokpo Maritime University who completed the on-board training in shipping company and the collected data were analyzed by SPSS Statistics 27. In this study, stress measurement, general characteristic analysis for participants, stress difference analysis, correlation analysis, multiple regression analysis, and multinomial logistic regression analysis were performed. As a result of this study, the overall average stress score was 2.88±0.65, in the order of technical factors, psychological factors, crews attitude, academic calendar, and social factors, these were analyzed as above-average stress levels. and stress analysis according to the general characteristics showed statistically significant results only in major satisfaction, job pride, and crew composition. correlation analysis showed statistically significant results as a whole, and in particular, the attitude of crew and psychological factors had a relatively high correlation. finally, it was analyed that attitude of crew and psychological factors affect overall stress through multiple regression analysis and multinomial logistic regression analysis. Therefore, it is necessary to make an effort for cadets to become effective on-board training by providing education that reflects these results in the education of the ship and university.

통합 센싱 시스템 기반의 스트레스 분석 웨어러블 설계

김봉현 국제차세대융합기술학회 2020 차세대융합기술학회논문지 Vol.4 No.4

현대사회에서 스트레스는 비만과 함께 만성질환의 원인으로 특별한 관리가 요구되고 있다. 특히, 과도한 스트레스는 사회적으로 매우 중요한 문제로 지적되고 있으며 이로 인해 스트레스성 질병과 사망, 흡연과 음주 그 리고 각종 범죄를 야기시키고 있다. 따라서, 본 논문에서는 통합 센싱 시스템 기반의 스트레스 분석 웨어러블 개 발에 관한 설계를 수행하였다. 이를 위해, 음성신호 체계 분석, 맥박 체계 분석, 피부저항 및 긴장도 분석 및 체온 분석 등을 통합적으로 연계하여 최적의 스트레스 측정 지표를 설계하는 연구를 수행하였다. 또한, 통합 데이터 분 석을 기반으로 하여 설계된 스트레스 측정 지표를 스마트 디바이스와의 연동으로 실시간 스트레스 측정 및 해결 방안을 출력하는 스트레스 분석 웨어러블을 설계하였다. In modern society, stress is a cause of chronic diseases along with obesity, and special management is required. In particular, excessive stress has been pointed out as a very important social issue. This leads to stressful illness and death, smoking and drinking and various crimes. Therefore, in this paper, the design of the stress analysis wearable development based on the integrated sensing system was performed. To this end, a study was conducted to design an optimal stress measurement index by integrating voice signal system analysis, pulse system analysis, skin resistance and tension analysis, and body temperature analysis. In addition, a stress measurement index designed based on integrated data analysis was linked with a smart device. And, a stress analysis wearable was designed to output real-time stress measurement and solution.

정지궤도복합위성 추진계 배관망 구조해석

정규,임재혁,채종원,전형열 항공우주시스템공학회 2018 항공우주시스템공학회지 Vol.12 No.1

In this paper, the structural analysis of the Geostationary Korea Multi-Purpose Satellite-2 (GEO-KOMPSAT-2) tubing system is discussed, and the structural integrity of the tubing system is assessed by comparative analysis with the results of overseas partner AIRBUS. Securing structural reliability of the tubing system is a very important key element of the propulsion system of the GEO-KOMPSAT-2 satellite. Therefore, FE modeling of the propulsion tubing was carried out directly using the CAE program, and structural analysis was performed to evaluate the stress state under launch conditions. Hoop stress, axial stress, bending stress, and torsion stress were calculated according to diverse load conditions by using pressure stress analysis, thruster alignment analysis, sine qualification load analysis, and random qualification load analysis. From the results, the Margin of Safety (MoS) of the tubing system is evaluated, and we can verify the structural integrity of the tubing system when subjected to various launch loads. 본 논문에서는 정지궤도복합위성 추진계 배관망의 독자적인 구조해석을 실시하였고, AIRBUS의 구조해석결과와 비교분석을 통해 추진계 배관망의 구조적 건전성 및 해석방법의 신뢰성을 평가하였다. 추진계 배관망의 구조적 신뢰성 확보는 정지궤도복합위성 추진계의 매우 중요한 핵심요소이다. 따라서 CAE 프로그램을 통해 직접 추진계 배관망 모델링을 수행하였고, 발사환경에서 구조해석을 실시하여 응력을도출하였다. 내압응력해석, 조립정렬해석, 정현파진동해석, 랜덤진동해석의 하중조건에 따라 Hoop stress, Axial stress, Bending stress, Torsion stress를 구하였고, 이를 모두 고려한 von Mises 응력 계산 후 안전여유 결과 값을 도출함으로써 추진계 배관망의 구조적 건전성을 판단하였다.

대학생의 스트레스 프로파일링 및 등록금 관련 변인의 관련성 검증

이은진(Eunjin Lee),홍세희(Sehee Hong) 한국자료분석학회 2022 Journal of the Korean Data Analysis Society Vol.24 No.1

대학생은 미래에 대한 다양한 가능성을 탐색하는 성장과 불안정성의 시기를 겪게 된다. 이 과정에서 학생들은 학업 스트레스, 진로 스트레스, 경제적 스트레스 등 다양한 스트레스와 직면하게 된다. 대학 등록금은 대학생의 스트레스를 촉진하는 요인으로, 우리나라의 경우 비교적 높은 등록금과 낮은 장학금 수혜 비율로 인해 그 문제가 더욱 심각하다. 이에 본 연구에서는 4년제대학 재학생의 스트레스의 잠재프로파일을 분류하고, 등록금 관련 변인이 스트레스 유형 분류에 미치는 영향을 검증하였다. 이를 위해 한국장학패널(KOSAPS)의 제2차연도 4년제 대학 재학생의 응답 자료를 토대로 잠재프로파일분석과 다중 로지스틱 회귀분석을 실시하였다. 분석 결과, 첫째, 대학생의 스트레스는 4가지의 잠재프로파일로 분류할 수 있었으며 그 형태에 따라 ‘저스트레스 집단(10.2%)’, ‘중스트레스-경제적 스트레스 집중 집단(26.4%)’, ‘중스트레스-진로 스트레스 집중 집단(27.7%)’, ‘고스트레스 집단(35.7%)’으로 명명하였다. 계층별 개인 특성, 가정 특성, 학교특성 변인의 기술통계치를 통해 각 계층의 특성을 파악하였으며, 장학금 관련 요인으로 다중 로지스틱 회귀분석을 실시하여 영향요인을 검증하였다. 장학금 관련 요인으로는 등록금에 관한 객관적 변인인 소득연계형 장학금(국가장학금Ⅰ·Ⅱ유형, 다자녀 국가장학금), 학자금 대출(취업 후 상환 학자금대출, 일반 상환 학자금대출, 농촌출신대학생 학자금 융자), 등록금에 관한 주관적 변인인 등록금 부담감이 스트레스 계층 분류에 유의하였다. 본 연구는 4년제 대학 재학생 스트레스의 잠재프로파일 유형과 이에 대한 등록금 관련 변인의 효과를 알아봄으로써, 대학생의 스트레스 특성에 대한 이해를 높이고 한국장학재단 지원사업 및 등록금에 대한 주관적 인식이 대학생의 스트레스에 미치는 영향을 검증한 것에 의의가 있다. 이러한 결과를 토대로 학자금 지원정책과 대학생의 스트레스 관리를 위한 정책적 제언 및 시사점을 제시하였다. The youth experience a period of growth and instability that explores various possibilities for the future in university. They often face many kinds of stress, such as academic stress, career stress, and financial stress. University tuition is a factor that causes stress for university students. The problem is even more serious for Korean students due to the relatively high tuition and low scholarship rates. Thus, the current study classified latent profiles of the stress of four-year university students and verified the effect of tuition-related variables on stress type classification. Latent profile analysis and multiple logistic regression analysis were conducted with the 2nd panel of the Korea Student Aid Panel Survey (KOSAPS). Students are classified into four latent classes: low-stress class (10.2%), medium -financial stress concentration class (26.4%), medium-career stress concentration class (27.7%), and high-stress class (35.7%). The current study examined descriptive statistics of individual, family, and school characteristics variables by class to inspect the characteristics of each class. Multinomial logistic regression analysis showed that the factors determining the profiles were need-based aid (National Grant Type I and II, Multi-Child Grant), student loans (Income Contingent Loan, Direct Loan, Loan for Rural Students), and tuition burden. This study has its implication in enhancing the understanding of the stress characteristics of university students and verifying the effect of the Korea Student Aid Foundation (KOSAF) aid project and students’ subjective recognition on tuition by examining the potential profile type and tuition-related variables. Based on the above results, this article presents policy suggestions and implications on university student aid policy and stress management.

A latent class analysis of life stress among female East Asian college students: A multi-country study

Jeongok Park,Ahyoung Cho,Hyojin Lee 한국성인간호학회 2021 성인간호학회 학술대회 Vol.2021 No.8

Aim(s): College students are known to experience large amounts of stress due to personal and environmental changes as they enter early adulthood. Especially female college students tend to report more life stress than male college students. Since stress has a significant impact on both one’s psychological and physical health, understanding college students’ experienced life stress is important. This study aimed to classify patterns of life stress experienced by female East Asian college students and identify factors associated with it for the purpose of designing appropriate measures to reduce female college students’ level of stress. Method(s): This study was a descriptive study design. The data were collected by on-line survey from June 2019 to October 2019. The whole dataset consisted of 520 female East Asian college students (220 for South Korea and 300 for Hong Kong). The Life Stress Scale for college students was used to measure the frequency of life stress of the participants. The data were analyzed with descriptive analysis, one-way analysis of variance, the chi-square test and latent class analysis. This study was approved by the Institutional Review Board (IRB) of Yonsei University (Y-2020-0205). Result(s): The mean age of the participants was 21.28 for South Korea and 20.36 for Hong Kong. In south Korea, participants were classified into two latent groups: “life stress high” (18.6%), and “life stress low” (81.4%). The two groups were significantly different for all factors in life stress subcategories (p<0.05) and subjective health status was the factor which differentiate between the two groups (X2=6.926, p=0.032). In Hong Kong, on the other hand, participants were classified into three latent groups: “life stress high” (13.7%), “life stress moderate” (43.9%), and “life stress low” (42.4%). Three groups were also significantly different for most factors in life stress subcategories (p<0.05). Each groups were different in financial status of parents (X2=11.484, p=0.019), subjective health status (X2=19.436, p=0.001), and body mass index (X2=10.421, p=0.034). Conclusion(s): This research provides insights into characteristics of life stress experienced by female East Asian students in college and suggests possible intervention measures to reduce stress. Thus, maintaining good health through physical activity and receiving informal social support at the various level like family, society, and nation will be important for female college students to manage their stress levels.

아로마테라피가 스트레스에 미치는 영향에 대한 메타분석

박정연(Jeong Yeon Park),박채영(Chae Young Park) 한국인체미용예술학회 2017 한국인체미용예술학회지 Vol.18 No.3

This study is intended to look into the effects of aromatherapy on stress. To achieve this, it collected at the effects of aromatherapy about stress based on the several accumulating quantitative and qualitative research related to verifying the effectiveness of aromatherapy, and that applied a meta-analysis to calculate the analysis results. The focus of this study was master s and doctoral papers released in Korea from 2004 to 2015. Of these papers, there was a final selection of 12 papers that had identified the effects of stress by conducting experimental aromatherapy treatments with an experimental group and a control group, and had clearly specified statistical figures (mean, standard deviation) for calculating the effect size. Though different results among these studies were produced, the statistical methods of meta analysis, which can indicate the integrated results of high statistical power without being biased toward the results of only some studies, were used to examine the collected data. The effect size and the integrated effect size of individual research for the finally selected 12 papers by dependent variables showed that there were 8 papers concerning stress, 5 concerning psychological stress, 5 concerning physical stress, and 3 about state anxiety. In addition, a meta analysis showed that aromatherapy had significant effects for the management of psychological stress, physical stress, and state anxiety. This suggests that the prevention of various stress diseases and the reduction of stress in everyday life must find ways to use aromatherapy as management therapy. The various programs look likely to be used in the esthetic field by integrating aromatherapy and massage with modern individuals who prefer naturopathy due to side effects of drug toxicity in terms of cosmetology.