• Journal of Korean Clinical Health Science
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• v.8 no.1
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• pp.1386-1397
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• 2020

Purpose: To examine the effectiveness of various treatments; bifocal spectacles, orthokeratology, atropine, and time spent in outdoors; in slowing down the myopia progression for Asian adolescents (6-18age). Methods: The research focused on examining the most effective treatment in controlling myopia based on the literature sources that have been published. Through meta-analysis of various research papers that already has been done in this field, a lot of data was collected. For each treatment, the difference in axial length and spherical equivalent over time was measured and recorded. To quantitatively record the difference, both axial length and spherical equivalent was determined by value of control group value of treatment group. The paper compared the effectiveness of each treatment based on the data that was measured. Results: Adolescents who chose to spend time outdoors in order to slow down myopia progression had axial length difference of 0.03 mm and spherical equivalent difference of 0.17 D. Adolescents that used atropine had axial length difference of 0.36 mm and spherical equivalent difference of 0.92 D. Bifocal spectacle resulted in axial length difference of 0.21 mm and spherical equivalent difference of 0.59 D, and for orthokeratology 0.23 mm and 0.04 D, respectively. Axial length wise, myopia was most controlled by the atropine since there was a greatest difference between the group that got the treatment and the group that did not have the treatment. According to the spherical equivalent difference data, myopia was most controlled by atropine. Conclusion: Atropine showed the most effective result in controlling myopia among the four treatment. Again, compared to other three treatment, using atropine appeared to have greatest ability in slowing down myopia progression since adolescents who were treated with atropine had greatest difference from adolescents in the control group that had the same condition but didn't get the treatment. However, every treatment was only used for 2 or 3 years which is quite short time period to measure the long term effect of the four treatments. Also, since atropine is a pharmaceutical method to control myopia, it may harm adolescents' eyes compared to optical or environmental treatment.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.25 no.1
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• pp.27-38
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• 1995

The organ or tissue doses were determined with head and neck phantom measurement for multiple axial scans (36 slices), multiple coronal scans (13 slices), 3 types of single axial scans(orbit, maxillary sinus and mandibular canal) and single coronal scan (maxillary sinus). For each scan sequence 30 TLDs were placed in selected sites(16 internal sites and 14 external sites) in a tissue-equivalent phantom. The exposure was made at 120kVp, 500mAs with 5 mm slice width. The results were as follows : 1. In multiple axial scans, the greatest effective dose recorded was that delivered to the thyroid glands(2.77 mSv) and the least was that received by the skin(0.05 mSv). From these data, stochastic effects were 202.2x10/sup -6/ and 3.7×10/sup -6/, respectively. 2. In multiple coronal scans, the greatest effective dose recorded was that delivered to the salivary glands(0.58 mSv) and the least was that received by the skin(0.01 mSv). From these data, stochastic effects were 42.2×10/sup -6/ and 0.7×10/sup -6/, repectively. 3. Among single axial scans, the greatest effective dose recorded was that delivered to the salivary gland(0.38 mSv) in maxillary sinus scan. From this data, stochastic effect was 27.7×10/sup -6/. 4. In single coronal scan, the greatest effective dose recorded was that delivered to the salivary gland(0.01 mSv). From this data, stochastic effect was 1.0×10/sup -6/. 5. The equivalent dose measured that delivered to the lens of the eyes was 69.64 mSv in multiple axial scan, 39.32 mSv in multiple coronal scan and 36.77 mSv in single axial scan(orbit).

• Journal of the Korean Geotechnical Society
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• v.35 no.12
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• pp.25-33
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• 2019

In this study, the axial stiffness of existing piles (K_ve) of vertical extension remodeled building was quantified through theoretical and experimental approaches. Theoretically induced upper and lower boundary of the pile axial stiffness was estimated by using the formula proposed by Randolph and Wroth (1978), which can estimate the axial stiffness of rigid and flexible pile subjected under soil confinement. In addition, 38 cases of field measurement data on deteriorated piles with various diameters constructed in the period between 1995 - 1997 were taken in to account by overlapping the field data with the theoretical boundary of the axial stiffness. Through this the maximum axial stiffness of existing pile due to deterioration and long service time was presented for various slenderness ratio (L/D), which can be used in estimating the necessary axial stiffness of reinforcing piles(K_vr) for the vertical extension remodeling. The lower 95% value of the estimated axial stiffness of existing pile will be induced through statistical processing.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.764-769
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• 2006

Vibration test on MAST(multi axial simulation table) system has several advantage over one-axial vibration test that could simulate 6-DOF, 3-axial translation and 3-axial moment, at the same time. Since field vibration motion can be fully represented with 6-DOF, multi-axial vibration test on vehicle component is widely conducted in technical leading companies to make sure its fatigue performance in vibration environment. On the way to fulfill the process, editing technique of obtained field data is key issue to success a reliable vibration testing with MAST system. Since the original signals are not only too large to fulfill it directly, but all of the measured data is not guarantee its convergency on generating its driving files, editing technique of the original signals are highly required to make some events that should meet the equal fatigue damage on the target component In this paper, key technique on editing a field data feasible for MAST system is described based on energy method in vibration fatigue. To explain its technique explicitly, author first introduced a process on field data acquisition of two vehicle component and then, representing events are produced to keep up with the editing strategy about a energy method. In the final chapter, a time information regarding a vibration test on MAST system is derived from the energy data which is critical information to perform a vibration test.

• Computers and Concrete
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• v.31 no.1
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• pp.1-7
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• 2023

In this paper, Timoshenko-beam model is developed for the vibration of double carbon nanotubes. The resulting frequencies are gained for axial wave mode and length-to-diameter ratios. The natural frequency becomes more prominent for lower length-to-diameter ratios and diminished for higher ratios. The converse behavior is observed for axial wave mode with clamped-clamped and clamped-free boundary conditions. The frequencies of clamped-free are lower than that of clamped-clamped boundary condition. The eigen solution is obtained to extract the frequencies of double walled carbon nanotubes using Galerkin's method through axial deformation function. Computer softer MATLAB is used for formation of frequency values. The frequency data is compared with available literature and found to be in agreement.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.205-208
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• 2006

This paper proposes a new computational aeroacoustics method for an axial fan analysis. The major aeroacoustic noise source of an outdoor air-conditioner is the axial fan. It was revealed that the dominant noise source is the aerodynamic interactions between the rotating blade and stationary orifice. Many researches were focused on the fan only case. However, it does not fit to a real outdoor unit of air-conditioner. Especially, the inlet part of the axial fan of real system case is complex and not uniform. So, in order to identify the dominant noise source of axial fan, full outdoor unit analysis is important. Transient CFD analysis of full system was performed by commercial CFD code - SC/Tetra. Dominant noise source of the system was calculated by commercial CFN code - FlowNoise. The results show that not only BPF peaks but also broadband noise are similar to the measured data.

• Steel and Composite Structures
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• v.16 no.1
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• pp.59-75
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• 2014

A new concrete confinement model is developed to predict the axial load versus displacement behavior of circular columns under concentric axial load. The new confinement model is proposed for concrete filled steel tube columns as well as circular reinforced concrete columns with steel tube jacketing. Existing confinement models were evaluated and improved using available experimental data from different sets of columns tested under similar loading conditions. The proposed model is based on commonly used confinement models with an emphasis on modifying the effective confining pressure coefficient utilizing the strength of the unconfined concrete and the steel tube, the length of the column, and the thickness of the steel tube. The proposed model predicts the ultimate axial strength and the corresponding strain with an acceptable degree of accuracy while also highlighting the importance of the manner in which the steel tube is used.

• Spatial Information Research
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• v.18 no.4
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• pp.99-108
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• 2010

Space Syntax methodology can be quantitatively calculated spatial cognitive analysis by number of turns_ In the existing GIS-based spatial information service provide 'physical distance' due to the shortest distance as a priority. but pedestrians tends to choose the path with concerned a lot of emphasis of safety, more vitality way from the crime at night, traffic accidents, and comfort on a road. Human's 'psychological distance' may reflect the spatial information services and provided path should be. In this study, using GIS Road Data implements the axial map with idea of the linear simplification principles. Traditional axial map of the Space Syntax get the assumption from the actual traffic values by comparing the results of correlation relationship. Through these methods, the actual relationship between traffic and test values have the correlation value($R^2$= 0.5387) 50% level and was able to get the results.

• Journal of Auto-vehicle Safety Association
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• v.8 no.1
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• pp.26-30
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• 2016

The steel road wheel on ventilation holes was cracked in the vehicle durability test. But the component durability test by uni-axial, CFT(Cornering Fatigue Test) and RFT(Radial Fatigue Test) had been satisfied. That is, the uni-axial component test could not forecast the crack of vehicle. Therefore this study developed the bi-axial test mode to reflect a vehicle condition(to reflect both vertical and lateral force simultaneously) based on real load data which was measured in Europe and China and developed CAE simulation too. It reproduced the cracks same as vehicle's and verified by bi-axial test machine in the LBF(Fraunhofer Institute for Structural Durability and System Reliability) durability research center in Germany. Finally this the durability CAE simulation by using HMC(Hyundai Motor Company)'s the bi-axial test mode predicts feasibly the steel wheel's durability performance before vehicle durability test.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.2
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• pp.141-148
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• 2009

Axial-flow compressor is one of the most important parts of gas turbine units with axial turbine and combustor. Therefore, precise prediction of performance is very important for development of new compressor or modification of existing one. Meanline analysis is a simple, fast and powerful method for performance prediction of axial-flow compressors with different geometries. So, Meanline analysis is frequently used in preliminary design stage and performance analysis for given geometry data. Much correlations for meanline analysis have been developed theoretically and experimentally for estimating various types of losses and flow deviation angle for long time. In present study, meanline analysis program was developed to estimate compressor losses, incidence angles, deviation angles, stall and surge conditions with many correlations. Performance prediction of one stage axial compressors is conducted with this meanline analysis program. The comparison between experimental and numerical results show a good agreement. This meanline analysis program can be used for various types of single stage axial-flow compressors with different geometries, as well as multistage axial-flow compressors.