• Proceedings of the KSME Conference
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• 2001.06d
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• pp.553-558
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• 2001

To find the effective combinations of blowing ratio and injection angle for a straight slot film cooling, film cooling characteristics was investigated using both flow visualization experiment and numerical simulation. Injection angles from $15^{\circ}\;to\;50^{\circ}$ and blowing ratios from 0.2 to 3.0 were selected for the simulation. Comparison between experimental and numerical results shows a good agreement, for the case of the injection angle of $30^{\circ}$ and blowing ratio ranging from 0.55 to 2.0. Film cooling effectiveness was found to be an increasing function of blowing ratio. The effects of injection angle became prominent as the blowing ratio increases. An interesting phenomenon was found for the injection angle of $15^{\circ}$ : the lowest film cooling effectiveness for the blowing ratio smaller than 1.0, but the highest film cooling effectiveness for the blowing ratio greater than 2.0 within wide range of downstream region. There exist optimum injection angles corresponding to maximum film cooling effectiveness : injection angle of $25^{\circ}$ for the blowing ratio from 0.2 to 2.0, and injection angle of $15^{\circ}$ for the blowing ratio of 3.0. Present study provides a design combination among film cooling effectiveness, blowing ratio, and injection angle.

• Journal of The Korea Institute of Healthcare Architecture
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• v.21 no.2
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• pp.55-65
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• 2015

Purpose: Korea is increasing in the demand for medical services due to rapid economic growth and population aging in modern society. Thus, the importance has been emphasized for the health promotion in the community and the publicity and substantiality of public health centers. However, the environment is insufficient, compared to required functions and developed services as a urban public health center. The purpose of this study is to analysis the plane type and area composition of public health centers in Busan and to identify the property of their spatial configuration Methods: Eight public health centers in Busan, were classified, which had been selected as a medical tourism city. Subsequently, space requirements were analyzed, facilities were typed, vertical, horizontal spaces were reviewed, and area ratios by business function were calculated. Results: A review of the property of spatial configuration and an analysis of the area ratio revealed the three findings. 1)The horizontal analysis found various types: a single type, a multi-type, a radial type, and a circular type, 2)The vertical analysis showed that since a care function (general practice), and a task function (maternal and child health) were concentrated in lower level spaces, the lobby and core were closed located for providing quick medical services. 3)The analysis of the area ratio in public health centers in terms of their function indicated that each public health center' programs had the greatest influence on the area. Implications: This study attempted to present spatial structural problems and improvements for city public health center by identifying their state and classify their functions and types and by calculating the ratio of their area configuration according to the spatial composition. It was thus aimed to presenting implications in establish public functions and roles by activating business through in connection with the number of municipalities in many ways, such as regional health. medical welfare, etc. to improve the health of local residents, and by providing differentiated programs in accordance with local characteristics.

• The Journal of Korean Physical Therapy
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• v.25 no.6
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• pp.374-378
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• 2013

Purpose: Human body have biological rhythmic pattern in a day, which is affected by internal and external environmental factors. We investigated whether respiratory function was fluctuated according to the influence of time-of-day (around at 9 am, 1 pm, and 6 pm) in health subjects, using pulmonary function test (PFT). Methods: Eighteen healthy volunteers (8 men, mean ages; $22.4{\pm}1.6$, mean heights; $166.61{\pm}9.60$, mean weight; $59.3{\pm}10.3$) were recruited. Pulmonary function test (PFT) was measured at three time points in day, around 9 am, 1 pm, and 6 pm in calm research room with condition of under 55dB noise level, using a spirometer (Vmax 229, SensorMecis, USA). Forced vital capacity (FVC), forced expiratory volume at one second (FEV1), FVC/FEV1, and peak expiratory flow (PEF) were acquired. Results: In comparison of raw value of PFT among three time points, subjects showed generally better respiratory function at 9 am, than at other points, although no significance was found. In comparison of distribution of ranking for respiratory function in each individual, only PEF showed significant difference. In general, distributional ratio of subjects who showed best performance of respiratory function in a day was high. Conclusion: These findings showed that circadian rhythm by diurnal pattern was not detected on respiratory function throughout all day. But, best performance on respiratory function was observed mostly in the morning, although statistical significance did not exist.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.2
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• pp.135-143
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• 2014

Purpose: To evaluate the blue-light blocking ratio and luminous transmittance of blue-light blocking lenses using the blue-light hazard function as specified in international standard. Methods: In order to calculate the blue-light blocking ratio and luminous transmittance for a total of 41 blue-light blocking lenses from 8 manufacturers, UV-Vis spectrophotometer was used for measuring the spectral transmittance of wavelengths from 380 to 780 nm. Blue-light blocking ratio was calculated using blue-light hazard function as specified in ANSI Z80.3:2010 and ISO 13666(or Korean Standard KS B ISO 13666:2004). Results: The range of the blue-light blocking ratio was from 9.3 to 96.8%, the range of the transmittance from 53.5 to 92.7%, and the range of the luminous transmittance from 58.0% to 98.1%. In general the blue-light blocking lens prepared by coating tended to have a higher luminous transmittance, while those prepared by tinting a higher blue-light blocking ratio. Conclusions: The behavior of the spectral distribution of lenses showed the possibility of the performance improvement in the blue-light blocking lenses. Manufactures need to acquire their own technology that can evaluate the performance of blue-light blocking lens based in international standard.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.6
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• pp.57-64
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• 2000

In order to regulate cutting torque in milling, monitoring system should be set to a certain threshold. Radial immersion ratio is an important factor to determine the threshold and should be estimated in process for automatic regulation. In this paper, on-line estimation of the radial immersion ratio using spindle motor current in face milling is presented. When a tooth finishes sweeping, a sudden drop of cutting torque occurs. This torque drop is equal to the cutting torque acting on a single tooth at the swept angle of cut and can be acquired from cutting torque signals. Average cutting torque per revolution can also be calculated from cutting torque signals. The ratio of cutting torque acting on a single tooth at the swept angle of cut to the average cutting torque per revolution is a function of the swept angle of cut and the number of teeth. Using the magnitude of this ratio, the radial immersion ratio is estimated. Identical algorithm is adopted to estimate the immersion ratio based on the spindle motor current measurement. The experiments performed under different cutting conditions show that the radial immersion ratio can be estimated within 10% error range by the proposed method using spindle motor current. Varying immersion ratio is also estimated well using the presented algorithm.

• International Journal of Aeronautical and Space Sciences
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• v.9 no.2
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• pp.9-17
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• 2008

When the stagnation temperature of the combustion chamber or ambient air increases, the specific heats and their ratio do not remain constant any more, and start to vary with this temperature. The gas remains perfect, except, it will be calorically imperfect and thermally perfect. A new generalized form of the Prandtl Meyer function is developed, by adding the effect of variation of this temperature, lower than the threshold of dissociation. The new relation is presented in the form of integral of a complex analytical function, having an infinite derivative at the critical temperature. A robust numerical integration quadrature is presented in this context. The classical form of the Prandtl Meyer function of a perfect gas becomes a particular case of the developed form. The comparison is made with the perfect gas model for aim to present a limit of its application. The application is for air.

• ETRI Journal
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• v.41 no.2
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• pp.207-223
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• 2019

Network function virtualization can significantly improve the flexibility and effectiveness of network appliances via a mapping process called service function chaining. However, the failure of any single virtualized network function causes the breakdown of the entire chain, which results in resource wastage, delays, and significant data loss. Redundancy can be used to protect network appliances; however, when failures occur, it may significantly degrade network efficiency. In addition, it is difficult to efficiently map the primary and backups to optimize the management cost and service reliability without violating the capacity, delay, and reliability constraints, which is referred to as the reliability-aware service chaining mapping problem. In this paper, a mixed integer linear programming formulation is provided to address this problem along with a novel online algorithm that adopts the joint protection redundancy model and novel backup selection scheme. The results show that the proposed algorithm can significantly improve the request acceptance ratio and reduce the consumption of physical resources compared to existing backup algorithms.

• The Korean Journal of Emergency Medical Services
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• v.5 no.1
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• pp.15-22
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• 2001

This study has measured the pulmonary function by treadmill test for 6 young women who were in twenties, and analyzed the respiratory-circulatory function and the change of hormone and immune response after performing the exercise program (60% severity) for 10 weeks. The results are as follows; 1. 10 weeks regular exercise made a decrease in weight and body fat proportion, and improved the respiratory-circular function by increasing the maximum oxygen absorption and ventilation. 2. 10 weeks regular exercise made a significant increase in count of WBC, lymphocyte, and T lymphocyte, but a significant decrease in B lymphocyte. NK cell also showed an increase in counts, but insignificant. 3. 10 weeks regular exercise made a significant increase in blood norepinephrine level. Epinephrine and cortisol also showed an increase in count, but insignificant. In summary, it suggested that 10 weeks regular exercise improves the immune function by decrease in body fat, increase in respiratory-circular function and metabolic efficiency, and also by raising Th/Ts ratio (an increase in count of WBC, lymphocyte, and T lymphocyte, but a decrease in suppressor T lymphocyte).

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1639-1642
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• 1997

In this paper, the autonomic function analysis system was designed to noninvasively assess the autonomic function of cardiovascular system. Orthostatic stress protocol was designed to stimulate the autonomic nervous system. designed protocol and analysis algorithm were evaluated by experiments for 25 normal subjects and 22 hemiplegia patients. Data were processed by usign the power spectral analysis. Nwe indexes of autonomic function, LF$_{N}$ and HF$_{N}$, were proposed and were compared with LF/HF ratio. New indexes of the sympathetic and parasympathetic activity, respectively. The IST and the DPT are balanced and have positive value for normal subjects during orthostatic stress but not for hempilegia patients. This result suggest that the IST and the DPT are used as new criteria of normal autonomic function during orthostatic stress.ess.

• Journal of Powder Materials
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• v.10 no.3
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• pp.201-208
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• 2003

Distributions of diamond particles protruding on the surface of worn diamond segments in circular saw has been investigated. Scanning electron microscope was used to examine the worn ,surface and radial saw blade wear and grinding ratio was measured. The number of protruded diamond particle was approximately 50% of the total number of particles, and that was independent of diamond particle concentration and table speed. It was also noted that the inter-particle distance did not follow a symmetric function like Gaussian distribution function, instead it fitted well with a probability density function based on gamma function. The distribution of inter-particle spacing, therefore, was analyzed using a gamma function model.