• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.321-325
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• 2010

Supersonic ejectors are simple mechanical components, which generally perform mixing and/or recompression of two fluid streams. Ejectors have found many applications in engineering. In aerospace engineering, they are used for altitude testing of a propulsion system by reducing the pressure of a test chamber. It is composed of three major sections: a vacuum test chamber, a propulsive nozzle, and a supersonic exhaust diffuser. This paper aims at the improvement of ejector-diffuser performance by focusing attention on reducing exhaust back flow into the test chamber, since alteration of the backflow or recirculation pattern appears as one of the potential means of significantly improving low supersonic ejector-diffuser performance. The simplest backflow-reduction device was an orifice plate at the duct inlet, which would pass the jet and entrained fluid but impede the movement of fluid upstream along the wall. Results clearly showed that the performance of ejector-diffuser system was improved for certain a range of system pressure ratios, whereas the orifice plate was detrimental to the ejector performance for higher pressure ratios. It is also found that there is no change in the performance of diffuser with orifice at its inlet, in terms of its pressure recovery. Hence an appropriately sized orifice system should produce considerable improvement in the ejector-diffuser performance in the intended range of pressure ratios.

• The Journal of Korean Physical Therapy
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• v.13 no.1
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• pp.107-114
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• 2001

Recently the number of elderly have been increasing at a rapid pace in Korea. Accompanying this aged society are numerous health problems. Whit this in mind health-promotion behaviors such as physical activity. good nutrition and stress management are vitally important to the elderly in reducing the risk of Health problems, maintaining health and improving the overall quality of life. Health promotion programs for the elderly must be developed. The purpose of th is study was to determine influential cognitive factors on health-promotion behaviors and the effects of previously implemented Health promotion programs. For this, previous studies were reviewed and analyzed. The results were as follows. 1. Cognitive factors on health-promotion behaviors were internal locus of control, perceived health status, self-efficacy, concerns about health, social support, attending social activities. 2. Components of health promotion programs were exercise and health education. Exercise was performed in most programs. The effects of exercise programs were improved flexibility, muscle strength. balance, cardiopulmonary function and elevated ability of daily living, perceived health status, quality of lift and a decrease depression. The results strongly suggest that complex health promotion programs should be developed. Health promotion programs need to include exercise, health education, health counseling and social activities. We have to consider cognitive factors on health-promotion behaviors.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.1
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• pp.98-103
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• 2007

In the present study, the author intended to investigate whether Gamiyukgunja-tang (Jiaweiliujunzi-tang, GYGT) significantly affect both mucin release from and MUC5AC gene expression in cultured hamster tracheal surface epithelial (HTSE) cells. Confluent HTSE cells were metabolically radiolabeled with 3H-glucosamine for 24 hrs and chased for 30 min in the presence of GYGT to assess the effect on 3H-mucin release. Possible cytotoxicity of the agent was assessed by measuring lactate dehydrogenase (LDH) release. Total elution profiles of control spent media and treatment sample through Sepharose CL-4B column were analysed and effect of GYGT on MUC5AC gene expression in cultured HTSE cells were investigated. GYGT did not affect mucin release from cultured HTSE cells. GYGT did not show significant cytotoxicity. GYGT also did not affect the secretion of the other releasable glycoproteins with less molecular weight than mucin. GYGT increased the expression level of MUC5AC gene. We suggest that the effect of GYGT with their components should be further investigated through ongoing research.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1994-1998
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• 2005

Characteristic analysis of the depth measurement system with a laser, a camera and a rotating mirror has been done and the parameter calibration technique for it has been proposed. In the proposed depth measurement system, the laser beam is reflected to the object by the rotating mirror and again the position of the laser beam is observed through the same mirror by the camera. The depth of the object pointed by the laser beam is computed depending on the pixel position on the CCD. There involved several number of internal and external parameters such as inter-pixel distance, focal length, position and orientation of the system components in the depth measurement error. In this paper, it is shown through the error sensitivity analysis of the parameters that the most important parameters in the sense of error sources are the angle of the laser beam and the inter pixel distance. The calibration techniques to minimize the effect of such major parameters are proposed.

• Analytical Science and Technology
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• v.34 no.5
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• pp.202-211
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• 2021

Volatile organic compounds (VOCs) in hazardous air pollutants (HAPs) have been regulated by the Air Pollution Control Act (1978) and their atmospheric concentrations have been monitored in 39 monitor sites in Korea. However, measurement standards of volatile organic compounds (VOCs) in HAPs at ambient levels have not been established in Korea. Primary reference gas mixtures (measurement standards) at ambient levels are required for accurately monitoring atmospheric VOCs in HAPs and managing their emissions. In this study, primary reference gas mixtures (PRMs) at 5 nmol/mol were developed in order to establish primary national standards of VOCs in HAPs at ambient levels. Primary reference gas mixtures (PRMs) were prepared in pressurized aluminum cylinders with special internal surface treatment using gravimetric method. Analytical methods using gas chromatography-flame ionization detector (GC-FID) coupled with a cryogenic preconcentrator were also developed to verify the consistency of gravimetrically prepared HAP VOCs PRMs. Three different columns installed in the GC-FID were evaluated and compared for the retention times and separation of eighteen target components in a chromatogram. Results show that the HAP VOCs PRMs at 5 nmol/mol were consistent within a relative expanded uncertainty (k=2) of less than 3 % except acrylonitrile (less than 6 %) and the 18 VOCs were stable for 1 year within their associated uncertainties.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.3
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• pp.139-150
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• 2015

The major components of IoT(Internet of Things) environment are IoT devices rather than the conventional desktop computers. One of the intrinsic characteristics of IoT devices is diversity in view of data type and data access method. In addition, IoT devices usually deal with real-time data. In order to use such IoT data for internal business or cloud services, an IoT platform capable of easy domain management and consistent data access interface is required. This paper proposes a Linux FUSE-based virtual file system connecting IoT devices on POSIX file system view. It is possible to manage IoT domain with the native Linux utilities such as mkdir, mknod, ls and find in the file system. Also, the file system makes it possible to access or control IoT devices through POSIX interface such as open(), read(), write() or close() without any separate APIs or utilities. A test result shows that the management performance of the file system is lower than that of linux file system negligibly.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.17 no.4
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• pp.487-497
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• 2010

Purpose: This study examined the validity and reliability to develop a lifestyle evaluation tool for metabolic syndrome patients. Methods: A methodological research design was used. The construct factors and preliminary items were identified by reviewing previous researches and tools related to lifestyle and reviewed by ten experts. It was tested with 195 patients with metabolic syndrome in a university hospital. The data were analyzed with SPSS/WIN 14.0. Results: To test the validity, principal component analyses were used and resulted in the extraction of six components. The convergent validity resulted r= .72 (p<.001) with Health Promotion Lifestyle Profile. The discriminant validity with Center for Epidemiologic Studies Depression Scale resulted r= -.15 (p=.004). The Internal consistency of the tool had an Cronbach's a of .92. The self-report format Lifestyle Evaluation Tool for the patients with metabolic syndrome was developed with 36 items and four-rating scales:'physical activity and weight control' eight items, 'dietary habits' sixteen items, 'drinking and smoking' three items, 'sleep and rest' two items, 'stress' three items, 'drug and health management' four items. Conclusion: This Tool will evaluate health behaviors in patients with metabolic syndrome. Also, it will contribute to the development of nursing intervention to improve the metabolic syndrome patients' lifestyle.

• Korea Journal of Hospital Management
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• v.18 no.1
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• pp.70-87
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• 2013

This study investigated contents of mission statements for Strategic Management of hospitals in Korea and Japan. For the study, 44 tertiary care hospitals in korea, which were accredited by the Ministry of Health and Welfare, were selected. And 83 special functioning hospitals in Japan, which were approved by the Minister of Health, Labour and Welfare, were included. Both quantitative and qualitative analyses were conducted by classifying 5 components of the mission statement; market, service, philosophy, image, contribution. Findings from this study are as follow. First, hospitals in Korea emphasized image(93.2%) and philosophy(81.8%) components in their mission statements, whereas hospitals in Japan highlighted components of service(89.2%) and market(72.3%). In detail, mission statements of Korean tertiary care hospitals describe the components of hospital's image (93.2%), philosophy(81.8%), contribution(56.8%), market(22.7%) and service (18.2%) in order. On the other hand, mission statements of Japanese special functioning hospitals describe hospital's service(89.2%), market(72.3%), contribution(61.4%), image (49.4%) and philosophy(34.9%), respectively. Second, as results of Content analysis, there were some differences in mission statements of hospitals between two countries, and it is mainly from the divergences of standards for recognition of medical institutions, environmental factors, and different ways of mission statement description. For strategic hospital management, carrying out innovative restructuring organization or promoting of research and training for medical development is considered as a desirable approach. However, clear description of mission statement is more important and it is required for effective control and managing organization. And then the mission should be communicated within an organization so all internal members understand it and put their efforts to achieve the mission of organization. In conclusion, it is recommended that a leader and senior managers should re-evaluate its mission statement whether it reflects characteristics of an organization. In addition, a mission statement should be created or improved based on critical decision, as well as it should be clearly shared within an organization in order to become a future oriented organizations.

• International Journal of Computer Science & Network Security
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• v.24 no.8
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• pp.21-31
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• 2024

This study investigates the user experience (UX) of first aid training using virtual reality (VR) technology. As VR continues to be adopted for educational and training purposes, it is important to understand how learners perceive and engage with this medium for developing critical skills, such as first aid. In this study, we developed a VR application called "VR First Aid" that includes training modules on three emergency scenarios: heatstroke, shock, and seizure. The application has both tutorial and hands-on training components. We conducted a UX study by administering a questionnaire to participants. The UX of learning through the VR application was then compared to using a traditional e-book format. Results indicate that participants perceived stronger internal behavior control with the e-book but reported better confirmation, engagement, enjoyment, and intention to use when training with the VR system. Gender differences were also explored, revealing that female participants expressed greater interest in learning through the VR platform compared to male participants. These findings provide insights into the strengths and limitations of VR-based first aid training compared to traditional methods. Implications for the design and deployment of VR training systems are discussed, with a focus on optimizing the learner experience and learning outcomes.

• The Journal of Korean Medicine
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• v.29 no.3
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• pp.63-75
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• 2008

Objectives: In the present study, the author intended to investigate whether Gamijinhae-tang (Jiaweizhenke-tang) (GJHT) significantly affects both contractility of tracheal smooth muscle and mucin secretion from airway epithelial cells. Materials and Methods: Effect of GJHT on contractility of isolated tracheal smooth muscle of rabbit was investigated. Confluent hamster tracheal surface epithelial (HTSE) cells were metabolically radiolabeled with 3H-glucosamine for 24 hrs and chased for 30 min in the presence of GJHT to assess the effect of the agent on 3H-mucin secretion. At the same time, confluent NCI-H292 cells were chased for 30 min in the presence of GJHT to assess the effect of the agent on MUC5AC secretion by ELISA. Total elution profiles of control spent media and treatment sample (radioactive mucin) through Sepharose CL-4B column were analyzed. Also, effect of the agent on MUC5AC gene expression in cultured NCI-H292 cells was investigated. Possible cytotoxicities of the agent were assessed by measuring both lactate dehydrogenase (LDH) release from HTSE cells and examining the rate of survival and proliferation of NCI-H292 cells. Results: (1) GJHT inhibited Ach-induced contraction of isolated tracheal smooth muscle; (2) GJHT significantly increased mucin secretion from cultured HTSE cells. However, it did not affect MUC5AC secretion from NCI-H292 cells, only chiefly affecting the 'mucin' secretion; (3) GJHT did not significantly affect the expression levels of MUC5AC gene in cultured NCI-H292 cells; (4) GJHT did not significantly inhibit the survival and proliferation of NCI-H292 cells. However, it slightly increased LDH release from HTSE cells. Conclusion: The author suggests that effects of GJHT with their components should be further investigated and it is valuable to find, from oriental medical prescriptions, novel agents which might regulate mucin secretion from airway epithelial cells.