• Proceedings of the KSME Conference
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• 2005.11a
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• pp.133.2-133.2
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• 2005

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.583-586
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• 2017

Infrared signal measurement are conducted from a micro-turbo jet engine with different nozzle configurations. The conventional cone type, a S-shaped type with aspect ratio 5.2 and five rectangular type nozzle with different aspect ratios are used for this experiment work. The result show that infrared signal from the exhaust gas decrease as the aspect ratio increase. In case of S-shaped nozzle, the maximum infrared signal is reduced about 28.4% when compared of rectangular nozzle with aspect ratio 5(AR5).

• The Journal of Korean Obstetrics and Gynecology
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• v.24 no.4
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• pp.95-104
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• 2011

Objectives: The purpose of this study is to investigate the relationship between the degree of menopausal symptom and granulocyte/lymphocyte ratio, and heart rate varibility(HRV). Methods: From 11th April 2011 to 20th May 2011, a total 30 female subjects (age 41-60) was recruited. We evaluated the degree of menopausal symptoms by Kupperman' s index and measured subject's WBC differential count and HRV. The data were analyzed by Kruskal-Wallis test and Spearman correlation test using SPSS/PC ver 13.0 program. Results: 1. There was no statistically significant difference in granulocyte/lymphocyte ratio and HRV among 4 classified groups according to Kupperman's index.- Mild, Moderate, Severe and Urgent. 2. Granulocyte ratio and general symptom score(within Kupperman's index) significantly showed negative correlation coefficient(r=-0.499, p=0.005), and Lymphocyte ratio and general symptom score significantly showed positive correlation coefficient (r=0.374, p=0.042). 3. Granulocyte/lymphocyte ratio and HRV showed no significant correlation. Conclusions: There was no significant relation among the degree of menopausal symptoms and granulocyte/lymphocyte ratio, and HRV. But furthermore large scale study is required.

• Earthquakes and Structures
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• v.16 no.3
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• pp.359-368
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• 2019

This paper focuses on the study of dynamic analysis of thick plates resting on Winkler foundation. The governing equation is derived from Mindlin's theory. This study is a parametric analysis of the reflections of the thickness / span ratio, the aspect ratio and the boundary conditions on the earthquake excitations are studied. In the analysis, finite element method is used for spatial integration and the Newmark-${\beta}$ method is used for the time integration. While using finite element method, a new element is used. This element is 17-noded and it's formulation is derived from using higher order displacement shape functions. C++ program is used for the analyses. Graphs are presented to help engineers in the design of thick plates subjected to earthquake excitations. It is concluded that the 17-noded finite element is used in the earthquake analysis of thick plates. It is shown that the changes in the aspect ratio are more effective than the changes in the aspect ratio. The center displacements of the reinforced concrete thick clamped plates for b/a=1, and t/a=0.2, and for b/a=2, and t/a=0.2, reached their absolute maximum values of 0.00244 mm at 3.48 s, and of 0.00444 mm at 3.48 s, respectively.

• School Mathematics
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• v.5 no.4
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• pp.421-440
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• 2003

It is difficult for the learner to understand completely the ratio concept which forms a basis of proportional reasoning. And proportional reasoning is, on the one hand, the capstone of children's elementary school arithmetic and, the other hand, it is the cornerstone of all that is to follow. But school mathematics has centered on the teachings of algorithm without dealing with its essence and meaning. The purpose of this study is to analyze the essence of ratio concept from multidimensional viewpoint. In addition, this study will show the direction for improvement of ratio concept. For this purpose, I tried to analyze the historical development of ratio concept. Most mathematicians today consider ratio as fraction and, in effect, identify ratios with what mathematicians called the denominations of ratios. But Euclid did not. In line with Euclid's theory, ratio should not have been represented in the same way as fraction, and proportion should not have been represented as equation, but in line with the other's theory they might be. The two theories of ratios were running alongside each other, but the differences between them were not always clearly stated. Ratio can be interpreted as a function of an ordered pair of numbers or magnitude values. A ratio is a numerical expression of how much there is of one quantity in relation to another quantity. So ratio can be interpreted as a binary vector which differentiates between the absolute aspect of a vector -its size- and the comparative aspect-its slope. Analysis on ratio concept shows that its basic structure implies 'proportionality' and it is formalized through transmission from the understanding of the invariance of internal ratio to the understanding of constancy of external ratio. In the study, a fittingness(or comparison) and a covariation were examined as the intuitive origins of proportion and proportional reasoning. These form the basis of the protoquantitative knowledge. The development of sequences of proportional reasoning was examined. The first attempts at quantifying the relationships are usually additive reasoning. Additive reasoning appears as a precursor to proportional reasoning. Preproportions are followed by logical proportions which refer to the understanding of the logical relationships between the four terms of a proportion. Even though developmental psychologists often speak of proportional reasoning as though it were a global ability, other psychologists insist that the evolution of proportional reasoning is characterized by a gradual increase in local competence.

• Journal of Gastric Cancer
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• v.9 no.3
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• pp.78-87
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• 2009

Serum pepsinogen (sPG) is a marker of gastric mucosal atrophy, a condition that has been associated with an increased risk of gastric neoplasia. A low sPGI level and a low PG I/II ratio have been associated with severe gastric atrophy, and are frequently found in gastric cancer. Because the prevalence of gastric cancer is high in Korea, it would be convenient if a good biomarker for gastric cancer were developed. Two studies recently investigated the efficacy of sPG along with Helicobacter pylori (H. pylori) as a screening tool for gastric cancer. In these studies, sPG was measured using a Latex enhanced Turbidimetric Immunoassay. We found that H. pylori IgG status, age and gender were associated with serum pepsinogen levels. Thus, to increase the ability of the PG I/II ratio to detect atrophic gastritis, the cutoff value for the PG I/II ratio should be stratified according to the H. pylori IgG status. In addition, a PG I/II ratio ($\leq3.0$), which has been widely used as an international standard for gastric cancer, was found to be a reliable marker for the detection of gastric dysplasia or gastric cancer, especially of the intestinal type. The efficacy of the test in Korea was lower than the efficacy in Japan. However, the detecting power of a PG I/II ratio ($\leq3.0$) was significantly increased in the presence of H. pylori. The ratio together with H. pylori psotivitiy could provide a means of identifying persons at high risk of developing gastric cancer in Korea.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.6
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• pp.1107-1115
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• 1996

An investigation made of the easing contraction ratio according to sewing condition (seam line; wp, wf, 45$^{\circ}$ bias, stitch density; 13 stitch/cm (0.8 mm), 9 stitch/cm (1.1 mm), 6.5 stitch/ cm (1.5 mm), 5 stitch/cm (2 mm), 4 stitch/cm (2.5 mm), thread; sp 60$^{\circ}$s/2, sp 60$^{\circ}$s/3, st 60$^{\circ}$s/3, st 50$^{\circ}$s/3)) by lockstitch industrial sewing machine with shirring foot. The correlations of the easing and sewing conditions were by SPSS PC), and visual test was done by enlarged photo. The results obstained were as follows:. 1. The easing contraction ratio is increased in proportion to the low of stitch density. 2. The easing contraction ratio of wp, 45$^{\circ}$ bias is correlated with stitch density, and that of wf be with stitch density, elongation & weight. 3. The easing contraction ratio of 13 stitch/cm (0.8 mm), 9 stitch/cm (1.1 mm), 6.5 stitch/ cm (1.5 mm), 5 stitch/cm (2.0 mm) is correlated with flexible rigidity, and that of 4 stitch/ cm (2.5 mm) be with flexible rigidity and crease-resistance. 4. As a results of SPSS PC+ statistics, the easing contraction ratio is statistically correlated to the seam line, stitch density, upper thread tension, and fabric characteristics. 5. As a results of visual test by the enlarged photo, the limit of stitch density for easing contraction was 5 stitch/cm (2.0 mm).

• Journal of ILASS-Korea
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• v.3 no.4
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• pp.35-42
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• 1998

Laser Raman scattering method has been applied to measure equivalence ratio of methane/air and propane/air mixture in constant volume combustion chamber. We used high power KrF excimer laser$(\lambda=248nm)$ and a high gain ICCD camera to capture low intensity Raman signal. Raman shifts and Ram cross-sections of $H_2,\;O_2,\;N_2,\;CO_2,\;CH_4\;and\;C_3H_8$ were measured precisely. Our results showed an excellent agreement with other groups. Mole fraction measurement of $O_2\;and\;N_2$ from air showed that $O_2\;:\;N_2$ = 0.206 : 0.794. We used constant volume combustion chamber and gas injector which is operated at $5\sim10barg$. Methane and propane are used as a fuel. 50 Raman signal are obtained and ensemble averaged for measurement of equivalence ratio. Our measured results showed that the equivalence ratio of fuel/air mixture is reasonable at ${\pm}5%$ error range.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.2
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• pp.54-60
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• 2007

This study was conducted to investigate growth characteristics of irrigation period of greenary mats focused on management as a material to apply on rooftop. Using Sedum kamtschaticum, Sedum takesimense, Sedum reflexum, Sedum album and Sedum burrito greenary mats were made. The irrigation periods were every 3 days, 7 days, and 10 days after made each greenary mats.1. All treatments on survival ratio of 5 Sedum species were over 96%. Especially, new individuals were emerged from naturally detached leaves. 2. Growth of S. kamtschaticum, S. takesimense, S. reflexum were good on 7 day irrigation treatment. 3. The highest covering ratio of S. burrito was 3 day irrigation treatment, and the hightest of the others were 7 day irrigation treatment. Considerations for species selection, mixture, ratio and management were obtained from this study.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.420-423
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• 2003

A low temperature difference model Stirling engine is a small Stirling engine running with several degree of temperature difference without power output. In this study, the design parameters to give maximum power are discussed. As results, the phase angle is about 100 degree, and compression ratio is 1.5% of the ratio of heat source temperatures at maximum power condition.