• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.9
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• pp.717-724
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• 2020

We study the closing characteristics of a self-sustainable poppet valve which serves as a main oxidizer shut-off valve for liquid rocket engines. Numerical analysis for predicting closing transient responses are presented and the calculated results have been verified by a comparison with experimental data. The effective area of a pilot gas discharge system and the pressure distribution of passage flow around the valve moving part are shown to be main parameters in determining the closing characteristics for dry and cryogenic conditions, respectively. Moreover, it is presented that the passage flow pressure at the valve closing moment as well as the valve closing velocity can be effectively adjusted by the appropriate employment of the pilot gas.

• Korean Public Health Research
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• v.44 no.4
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• pp.15-24
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• 2018

Objective : This study explores whether and how the amount of smoking differs by economic status and perception among the men in working age. Methods : The study utilized the 4th wave of KoWEPS containing the items on perception of economic conditions. Analysis was conducted on ever-married men aged 30-54, who have capacity to work. It used 2 stage regression model methods to examine the mediation effect of perception on economic status. Results : The results shows that the negative perception on economic status has a positive effect on smoking. Disposable income affects smoking only through the perception of economic status. Employment status exerts both direct and indirect effect on smoking. Conclusions : These findings imply that less privileged economic status is related to smoking through anxiety or stress for the negative perception on it.

• Journal of the Korean Geotechnical Society
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• v.40 no.2
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• pp.55-64
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• 2024

While shield tunneling has demonstrated stability in international cases, the new Austrian tunneling method (NATM) encounters challenges in urban environments with shallow cover, weathered ground, and high groundwater levels. This paper introduces two typical collapse scenarios observed in urban areas, specifically within weathered bedrock and uncemented sandy soil layers. The collapses are analyzed using six stability evaluation methods, and the results are synthesized to assess the excavation face stability through a hexagonal diagram. The study finds a consistent agreement between the analysis results of the two collapsed tunnel sites and the evaluation outcomes. The employment of the stability evaluation diagram, a comprehensive method that considers the ground characteristics of the target tunnel, proves crucial for ensuring barrier stability during the tunnel design stage. This method is essential for a holistic evaluation, especially when addressing challenging ground conditions in urban settings.

• Journal of Labour Economics
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• v.26 no.2
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• pp.31-59
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• 2003

This paper analyzes a social insurance system that integrates unemployment insurance with a pension program, allowing workers to borrow against their future wage income to finance consumption during an unemployment episode and thus improving their search incentives while reducing risks. This paper identifies the conditions under which the integration improves welfare and the factors which determine the optimal degree of integration. A fully integrated system is one in which no reliance is placed at all on a separate tax-funded unemployment insurance program. We show that when the duration of unemployment is very short compared to the period of employment or retirement, the optimal system involves an exclusive reliance on pension-funded self-insurance. This system imposes a negligible risk burden for workers while avoiding attenuating search incentives. We also argue that a joint integration of several social insurance programs with a pension program through an individual account is desirable unless the risks are perfectly correlated to each other.

• Korean Institute of Interior Design Journal
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• v.22 no.5
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• pp.3-10
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• 2013

The principle of aging-in-place should be fundamental in designing post-retirement homes to support baby boomers' healthy aging in their current living conditions. This study investigated Korean-American baby boomers' opinions about their life images in their post-retirement homes and the needs for supportive services therein. A questionnaire survey was conducted, and a total of 247 responses were used for statistical analyses. As the most important life image for their post-retirement homes, baby boomers emphasized the living environments offering various recreational activities. They indicated the post-retirement homes close to their children or family members as the next important life image. These opinions differed depending on their socioeconomic characteristics. In particular, baby boomers with higher-income preferred housing environments offering diverse recreational activities while those with lower-income preferred the housing close to more employment opportunities. In terms of supportive services available in the post-retirement homes, they wanted 'healthcare assistance services' and 'diverse recreational programs.' Gender, educational attainment, and annual income affected their preferences in these services, though. Based on the findings, this study concluded that post-retirement housing environments should create spaces to accommodate various recreational activities and include places for them to work in near-home environments. In the community, various need-based customized recreational activities and educational programs should be planned considering different socioeconomic characteristics of baby boomers. All these considerations will provide supportive residential environments for their successful aging in place.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.291-296
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• 2011

This paper presents energy self-sufficiency simulated in municipal wastewater treatment plants (WWTPs) by adopting solar energy production systems that vary with installation conditions. Relative to the national average energy consumption in WWTPs, the employment of 100 kW photovoltaics (PVs) was simulated to achieve 2.75% of energy self-sufficiency. The simulated results suggested that the installation of PVs toward South or South west would produce the highest energy self-sufficiency in WWTPs. When super-hydrophilic coating was employed in the conventional PVs, 5% of additional solar energy production was achievable as compared to uncoated conventional PVs. When 100 kW of PVs were installed in a future test-bed site, Kihyeung Respida located in Yougin, Sourth Korea, the energy self-sufficiency by solar energy was simulated to be 1.77% (2010). The simulated energy self-sufficiency by azimuth(direction) will be useful reference for practitioners in designing the solar PV systems in the WWTPs.

• Korean Journal of Social Welfare Studies
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• v.41 no.1
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• pp.203-226
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• 2010

Using the Korean Welfare Panel Study, this study examines the labor-market activities of uninsured persons and discusses policy implications for reforming the National Pension Scheme in Korea. First, despite the short observation period, the data show that pension status is not a static state and can be better understood in terms of dynamic processes. Second, in addition to frequent changes in income-earning activities, complex criteria for pension coverage cause substantial transitions in pension status. Third, a portion of uninsured persons involve in income-earning activities but they tend to face poor working conditions as well as unstable employment. Overall, this study suggests that building solid foundations for developing a financially sustainable and reliable social protection system is more important than rapid increase in pension coverage.

• Journal of dental hygiene science
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• v.15 no.3
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• pp.265-271
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• 2015

This study has an objective not only to be helpful to the understanding about students' career and employment preparation by investigating the present conditions which are related with vocational consciousness and job values of dental hygiene department graduating students. Study subjects were 350 female graduating students in 3-year-course College, dental hygiene department at five areas of Seoul, Gyeonggi, Gangwon and Gyeongnam. Data were analyzed using IBM SPSS Statistics ver. 19.0. Regarding job values, job prospect of dental hygienist is a little developmental (55.2%) and institution hoping to work is dental clinic (43.2%), reasons for employment in major area are good wage and working environment (24.0%). And regarding opinion about job, dental hygienist job is a measure for living income (69.7%). Regarding job selection conditions, 35.0% subjects replied good human relationship. In the questionnaires regarding professional job in vocational consciousness category, results showed high percentages in that 'the occupation is a job in charge of oral health improvement'; regarding academic area, 'scaling should be done better than dentist'; regarding human relationship, 'harmony between colleagues is closely related with job efficiency'; regarding work ethics, 'development of dental hospital (clinic) and dental hygienist is correlated.' In vocational consciousness of study subjects, higher major satisfaction showed significant differences in professional job consciousness and work ethics consciousness (p<0.05) and the correlation results in vocational consciousness areas showed all statistically significant correlations (p<0.01). In case that the characteristic in one type is higher among 4 types, all other types showed high characteristics and also showed high general vocational consciousness.

• Journal of Korean Public Health Nursing
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• v.15 no.2
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• pp.225-238
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• 2001

The purpose of this study is to examine public health nurses for their morale, test the effect of each factor on the morale, determine the variables affecting the morale, and thereby, provide for some basic data useful to the development of personnel affair administration for nurses. The survey on the nurses for public health centers was conducted for 10 days from April 23 to May 2, 2001; 96 nurses from Pusan, 101 from Kyonggi-do and 108 from Kangwon-do. The results of the study are as follows; 1. For the demographic variables, those aged between 31 and 39 accounted for the majority $(50.2\%)$ of the sample. $90.8\%$ was married, and $67.9\%$ of the sample graduated from junior colleges. $29.6\%$ of them had worked for 10-14 years and $62.5\%$ was of the seventh rank. $62.3\%$ of the nurses was recruited, and $59.4\%$ had chosen the public job for its guaranteed status. Half the nurses were working for the county population of which was more than 260 thousands, and $53\%$ of the nurses was serving the public health centers with 11-15 members. $47.3\%$ of them perceived that their living standard is middle or lower. 2. The degree of the moral was found as mean score. 2.65, which is interpreted as low. It has 11 factors. The rank of mean score of the factors is job satisfaction (3.36), sense of belonging (3.36), sense of recognition (3.30), stress due to supervision (3.13), degree of participation (3.05) and self-achievement (3.04), while those scoring lower points were assurance of status (2.58), pay level (2.53), working conditions (2.35) and promotion opportunity (2.31). 3. The degree of moral depending on the demographic variables was significantly affected by such variables as age. academic background, career, rank, employment method, motive for the job, size of the population served and living standards. 4. The result of the Stepwise multiple regression analysis for the morale factors, it was found that self-achievement accounted for $61\%$ of the total variance of the degree of morale, followed by stable status $(18\%)$, working conditions $(8\%)$, job requirements $(4\%)$ and promotion opportunities $(2\%)$; these five factors explained about $94.6\%$ of total variance of the degree of nurses' morale. On the other hand. age $(8\%)$ and academic background $(2\%)$ accounted for $10\%$ of the total variance of the degree of morale. 5. The factors affecting nurses' job life was economic need $(26.7\%)$, personnel management $(17.5\%)$, sense of recognition $(13.2\%)$, human relationship $(11.0\%)$, stable status and personal development in rank. On the other hand, the factors influencing on their possible resignation were children's bringing-up $(27.8\%)$, poor personnel management and promotion $(13.3\%)$, workload $(11.1\%)$ and little personal development $(8.9\%)$, Since such morale factors as promotion opportunity, working condition. pay level and stable status scored lower, it is required to reconsider those factors to improve nurses' morale.

• Research in Community and Public Health Nursing
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• v.6 no.2
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• pp.299-318
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• 1995

This study was conducted in order to grasp the condition of the Worker's knowledge and attitude about health management. And to offer the basic materials for the health promotion in industrial field. The objects were comprised 336 of volunteered who work in E.shoemaking factory. The material of this study was the questionair (chronbach a=.8871) suited to the purposed of this research which has been made through studying references. All the guestionaire were collected inmediately without explanation. The data collected from 18th September to 1st Octover. Analysis of the data was done utilizing SAS program for percentage, mean, ANDVA. The result are as follows: 1. General features of the objects of study. Male was highest (58.6%), mean age was 30.07 years, graduated high school was highest(59.2%), producer in present place of employment was highest (76.2%), mean career was 7.45 years. 2. The conditions of attitude about health man agement. Correct answer of health examination was 77.8%. Having experience of health examination was 69.5%, among them have regularity was 70.9%. Think it too much trouble to do not health examination was 69.7%. Have got to do health examination was 95.6%. The reason of set up health clinic was emergency care 58.9%, health education 22.1%. Using health clinic was 70.4%, by monthly was 53.0%. The reason of think it too much trouble to use not health clinic was 65.2% The need of health clinic was 96.4% 3. The conditions of knowledge about health management. When 5 points was given to 'very affirming' and 1 point was given to 'very deny', the total average was 3.67, the range was 2.96-4.54. Exactly, company must given to employee put in operative health examination was highest, worked 34 hours per week on harmful worked place was lowest. And knowing about kind of harmful work was 2.86, dangerous work was 2.90. 4. Correlation between the general features and attitude variables. Female group may have more knowledge on reason of health examination. Over 50 years aged group, middle school graduated group, white colored group, less then 1 year career group may have more knowledge on health examination. White colored group may have more attitude on health examination$(\chi^2=5.210,\;P<.07)$. High careered group may have more using on health clinic $(\chi^2=12.08,\;P<.007)$. 5. Difference between the general features and knowledge of health management. High educated group were highest score in knowledge (F=5.214, P<.002). White colored group were highest score in knowledge (F=23.019, P<.000). 6. Difference between the attitude and knowledge of health management. Needing of health examination group were highest score in knowledge. (t=2.54, P<.011). Using of health clinic group were highest score in knowledge(t=190, P<.048). Needing of health clinic group were highest score in knowledge(t=5.13, P<.000).