• The Bulletin of The Korean Astronomical Society
• /
• v.42 no.2
• /
• pp.47.2-47.2
• /
• 2017

We investigate the environmental effects on galaxy spin using the sample of ~1100 galaxies from the first public data of MaNGA integral field unit survey. We determine the spin parameter ${\lambda}_{Re}$ of galaxies by analyzing the two-dimensional stellar kinematic measurements within the effective radius, and study its dependence on the large-scale (background mass density determined with 20 nearby galaxies) and small-scale (distance to and morphology of the nearest neighbor galaxy) environments. We first examine the mass dependence of galaxy spin, and find that the spin parameter decreases with stellar mass at log ($M_{\ast}/M_{\odot}$) > 10, consistent with previous studies. We then divide the galaxies into three subsamples using their stellar masses to minimize the mass effects on galaxy spin. The spin parameter of galaxies in each subsample does not change with the background density, but do change with the distance to and morphology of the nearest neighbor. The spin parameter increases when late-type neighbors are within the virial radius, and decreases when early-type neighbors are within the virial radius. These results suggest that the large-scale environments hardly affect the galaxy spin, but the effects of small-scale environments such as hydrodynamic galaxy-galaxy interactions are substantial.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.13 no.1
• /
• pp.147-162
• /
• 2021

The problem of predicting a ship's form factor and associated scale effects has been subject to many investigations in recent years. In this study, an attempt is made to investigate whether the form factor is influenced by a change in the ship's speed by numerically modelling a geosim series of the KCS hull form by means of a RANS solver. The turbulence dependence of the problem is also studied by altering the closure model among three widely used approaches (the k-𝜔, k-𝜔 SST, and k-𝜀 models). The results show that at very low speeds (Froude numbers in the range of 0.02-0.06) the numerical model predicts changes in the form factor of a ship between 10% and 20%, depending on the turbulence model and scale factor choices. As the speed is increased further, the form factor exhibits little change, usually in the range of 1% or less. Simulations where the Reynolds number is changed by approximately two orders of magnitude, achieved by altering the value of viscosity, confirmed that the form factor can be considered Froude-dependent only for low speeds, predicting essentially identical values when high speed cases are considered.

• Journal of the Korean Society of Visualization
• /
• v.20 no.3
• /
• pp.36-41
• /
• 2022

Drying process is involved in the production of various products including food, textiles, paper, pharmaceuticals, and batteries. Phase change of liquid to vapor generally requires enormous thermal energy, so in order to save energy, it is advantageous to develop an appropriate drier and use it under appropriate operating conditions, depending on the characteristics of materials. However, due to the complex, multiscale heat and mass transfer occurring during drying processes, predictions of appropriate drying conditions before actual operation are not easily achieved, leading to challenges in designing driers. Here, we developed a lab-scale experimental setup to evaluate the performance of band dries. The experimental setup was used to measure the moisture content and temperature change in the materials being dried in a belt dryer. Experimental results obtained using our lab-scale setup allow us to predict the performance of a full-scale band drier, thus suggesting a practical framework for predicting the drying process of various materials and developing band driers.

• Journal of the Korean Data and Information Science Society
• /
• v.18 no.2
• /
• pp.507-514
• /
• 2007

We shall propose several estimators for the scale parameter in the Pareto distribution with an unidentified exponential outlier when the scale parameter is functions of a known exposure level, and obtain expectations and variances for their proposed estimators. And we shall compare numerically efficiencies for proposed estimators of the scale and shape parameters in the small sample sizes.

• Journal of the Korean Data and Information Science Society
• /
• v.21 no.3
• /
• pp.581-587
• /
• 2010

We shall propose several estimators for the scale parameter in a uniform distri-bution with a generalized uniform outlier when the scale parameter is a function of a known exposure level, and obtain expectations and variances for their proposed estima-tors. And we shall compare numerically efficiencies for proposed estimators of changed parameters of the scale in the small sample sizes.

• Tuberculosis and Respiratory Diseases
• /
• v.39 no.5
• /
• pp.392-399
• /
• 1992

Background: Despite dyspnea is a predominant complaint of patients with respiratory disease, the mechanisms contributing to the sensation of breathlessness are poorly understood. Traditionally, physicians have measured objective pulmonary function to assess severity of dyspnea. But it will be also useful to measure subjective dyspnea index because dyspnea probably depends on a complex interplay of mechanical, experimental, emotional and other factors. Method: We measured breathlessness at rest, after Methacholine challenge and then bronchodilator inhalation using a Visual Analogue Scale (VAS) and Borg Scale Dyspnea Index (BSDI) in stable asthmatic patients. Spirometry was performed concomittently. Results: There was no correlation between dyspnea index and FEV1. There was also no correlation between the change in dyspnea index and change in FEV1. The change in dyspnea index after methacholine and bronchodilator was greater in clinically mild asthmatic patients than clinically severe symptomatic group. Conclusion: In asthmatic patients, there was a wide variation in sensory response for any given FEV1, and the change in perception of dyspnea was greater in those with clinically mild symptoms. The measurement of dyspnea index may yield information complementary to that obtained by spirometry.

• Journal of Korean Academy of Nursing
• /
• v.27 no.2
• /
• pp.401-410
• /
• 1997

An acute pain is the common experience following surgery. Pain is a most miserable experience in person and most preoperative patients have fear o! postoperative pain. In nursing, it is very important to understand and relieve the pain of post oprative patients as much as possible. This study was designed to compare the descriptive patterns of pain between group of Patient Controlled Analgesia and group of traditional Muscular Injection in surgcal patients. This information can be utilited as data of understanding nursing care and treatment planning for pain in surgical patients. The subjects in this study were 45 post-hysterectomy patients in Gynecology ward in C. N. U. H., in Taejon. Data was collected from May 12 to June 27. 1996. The instrumants used for this study were subjective Visual Analog Scale, Objedive nonverbal pain scale composed of Facial Apperance. Vocal Sound Change, and Sweating score. and the Melzack's Mcgill pain Qusetionaire. nine Items of Developmental Pain Intensity Scale by Lee En Ok. Analysis of data was done by using S. P. S. S. percentage, t-test, x²-test. ANOVA, and Repeated measure ANOVA. Results were obtained as follows. 1. Hypothesis 1 : There was very highly statistically significant difference in subjective self-report pain score(Visual Analog Scale) between PCA Group and IM Group(P=0.0001). 2. Hypothesis 2 : There was very highly statistically significant difference in muscle strength score (Visual Analog Scale) between PCA Group and IM group(P0.0001). 3. Hypothesis 3 : There was very highly statistically significant difference in facial appearance score between PCA Group and IM group(P=0.0001). 4. Hypothesis 4 : There was very highly statistically significance difference in vocal sound change score between PCA Group and IM group(P=0.0001). 5. Hypothesis 5 : There was no statistically significant difference sweating scores between PCA group and IM group(F=2.50, P=0.1220). But, postoperation time of 12, 24 was statistically difference between two groups(P=0.0001). So, it was partially supported. 6. Hypothesis 6 : There was very highly statistically significant difference in vocabulary pain score between PCA Group and IM group. 7. Hypothesis 7 : There was very highly statistically significant difference in amounts of total analgesic between PCA Group and IM group. There was very highly statistically significant difference in Visual Analog Pain Score, Facial Appearance Score, Vocal Sound Change Score, Vocabulary Score, amounts of total analgesic between PCA group and IM group. So, It is verified to asses of postoperative pain with VAS, Checklist of facia appearance, vocal sound change, and sweating, and Vocabulary Scale.

• Corrosion Science and Technology
• /
• v.7 no.3
• /
• pp.182-186
• /
• 2008

The microstructures of the oxide scale developed at high temperature on steels are very complex and their development depends on many factors including time, temperature, oxidation conditions and alloying elements. The classical model of an oxide scale on steel consisting of wüstite, magnetite and haematite layers, is more complicated in reality and its properties change with the factors that affect their development. An understanding of the oxide scale formation and its properties can only be achieved by careful examination of the scale microstructure. The oxide scale microstructure may be difficult to characterise by conventional techniques such as optical or standard scanning electron microscopy. An unambiguous characterisation of the scale and the correct identification of the phases within the scale are difficult unless the crystallographic structure for each phase in the scale is considered and a simultaneous microstructure-microtexture analysis is carried out. In the current study Electron Backscatter Diffraction (EBSD) has been used to investigate the microstructure of iron oxide layers grown on low carbon steels at different times and temperatures. EBSD has proved to be a powerful technique for identifying the individual phases in the oxide scale accurately. The results show that different grain shapes and sizes develop for each phase in the scale depending on time and temperature.

• International Journal of Fluid Machinery and Systems
• /
• v.4 no.2
• /
• pp.229-234
• /
• 2011

For Lift-type Vertical Axis Wind Turbine (VAWT), it is difficult to evaluate the performance through the scale-model wind tunnel tests, because of the scale effect relating to Reynolds number. However, it is beneficial to figure out the critical value of Reynolds number or minimum size of the Lift-type VAWT, when designing this type of micro wind turbine. Therefore, in this study, the performance of several scale-models of Lift-type VAWT (Reynolds number : $1.5{\times}10^4$ to $4.6{\times}10^4$) was investigated. As a result, the Reynolds number effect depends on the blade chord rather than the inlet velocity. In addition, there was a transition point of the Reynolds number to change the dominant driving force from Drag to Lift.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2008.05a
• /
• pp.159-163
• /
• 2008

The trend of Development Projects has been changing through a few recent years. Small-scale development projects in the past were usually for building residences or officetel in a big cities. making lots of profits. These projects made not only lots of profits but also unbalance between the urban centers and the suburbs. So government made some regulations to prevent the things from being worse anymore, planned to develop the country in balance and began to lead large-scale development project such as Inno city and Newtown. At first, in this study, the phases and the characteristics of development project's change will be looked around. And then, after overview about PFV(project financing vehicle) used a lot in large-scale development projects will be seen, the better ways to use PFV in large-scale development projects are going to be proposed by considering the problems in PFV's conformation.