• Journal of Korean Association for Spatial Structures
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• v.20 no.3
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• pp.15-20
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• 2020

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.3
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• pp.205-209
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• 2016

The flowfield characteristics of a square prism having a small triangular prism at the upstream side were investigated by visualizing the flow field using PIV. The ratio of the width of the triangular prism to that of the square prism and the gap ratios between the square and triangular prisms were selected as the experimental parameters. The results are summarized as follows. The Strouhal number measured on the wake side of the square prism, which had the same characteristics as the drag reduction rate, increased, and then decreased with the gap ratio for the same width ratio. For a square prism having a small triangular prism, the stagnation regions were represented at the upstream and downstream sides of the square prism. The size of the stagnation region increased with the width ratio at the upstream side of the square prism, and decreased at the downstream side.

• The Journal of Korean Academy of Prosthodontics
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• v.30 no.2
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• pp.273-285
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• 1992

The purpose of this study was to evaluate facial form, arch form and tooth form in young adults to determine if a correlation exists. 115 subjects who had healthy natural maxillary incisors and good occlusion consisted of 71 males and 44 females ranging from 20-30 years of age. Facial photographs and, intraoral photographs of upper anterior teeth and dental casts of upper jaws were taken to demonstrate facial form, dental arch form and tooth form. Form analysis is determined by comparing the ratio of the widths of the faces, dental archs and the teeth. The Chi-square test of independence between facial form, arch form and tooth form, was executed and the significance level determined. The results were as follows : 1. The distribution of facial forms was 66.1% square-tapering, 27.0% square, 5.2% ovoid, 2% tapering-square. 2. The distribution of tooth forms was 65.2% ovoid, 20.0% square-tapering, 11.3 % tapering-square, 3.5 % square. 3. The distribution of arch forms was 50.4 % square-tapering, 48.7 % tapering, 0.9 % reverse tapering-square. 4. There was no large differences in the distribution of facial forms, dental arch forms and tooth-forms between male and female. 5. No relationship existed between the tooth form and the facial form. 6. No relationship existed between the facial form and the dental arch form. 7. No relationship existed between the tooth form and the dental arch form. 8. This gave the impression that dental arch form and facial form could not be used as a true index in tooth selection.

• The Journal of Korean Medicine
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• v.27 no.1 s.65
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• pp.104-117
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• 2006

Objectives : To explore the causes that affect the level of Yangseng(養生) certain elderly people.(Level of Yanseng; The oriental medicine tool to measure Yanseng developed to fit the situation of korea) Methods : For this purpose, characteristics, Life Satisfaction and Activities of Daily Living were adopted as independent variables and analyzed statistically. Out of questionnaires distributed to the old people aged 65 or more living in Jeonbuk province, 824 replies were collected from April to June 2004 and processed for an analysis. Results : The analysis revealed that the higher points old persons tend to score in Total of Yangseng, the more they are inclined to be Life satisfaction, the higher K-ADL they get and the longer they have leisure. Rather old men than women or rather those who live with family than those who do not have more possibility to record higher scores of Total of Yangseng(R Square=0.365). There was greater possibility that the higher points persons can get in Morality Yangseng(R Square=0.200), Mind Yangseng(R Square=0.173), Diet Yangseng(R Square=0.139), Exercise Yangseng(R Square=0.353), Sleep Yangseng(R Square=0.187), Seasonal Yangseng(R Square=0.107), Sex life Yangseng(R Square=0.199), the more they tend to be Life satisfaction. It was revealed from the analysis that the better care old people pay to Activities & Rest Yangseng, the higher K-ADL they get(R Square=0.186). Conclusions : Front the above results, it may be concluded that approaches of Oriental medicine can contribute to maintaining and promoting health as well as preventing and controlling disease for old people who are in greater needs for proper health care in the aged period.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.3
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• pp.477-489
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• 2014

Based on some flaws occurred for implementing a public key cryptosystem in the embedded security device, many side-channel attacks to extract the secret private key have been tried. In spite of the fact that the cryptographic exponentiation is basically composed of a sequence of multiplications and squarings, a new Square Always exponentiation algorithm was recently presented as a countermeasure against side-channel attacks based on trading multiplications for squarings. In this paper, we propose Known Power Collision Analysis and modified Doubling attacks to break the Right-to-Left Square Always exponentiation algorithm which is known resistant to the existing side-channel attacks. And we also present a Collision-based Combined Attack which is a combinational method of fault attack and power collision analysis. Furthermore, we verify that the Square Always algorithm is vulnerable to the proposed side-channel attacks using computer simulation.

• Journal of the Korean Institute of Landscape Architecture
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• v.25 no.1
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• pp.36-46
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• 1997

Recently, The rural-pocket parks in Korea have been constructed for the recreation activities of the rural residents. The purpose of this study is to suggest planning guidelines focused on the minimum size. The methods used in this study are surveying the satisfaction of rural residents, analyzing the size of Rural-Pocket Parks recently constructed, and comparing with pocket parks in Seoul. The major findings of this study can be summarized as follows : 1) The average size of rural-pocket park in Kyung-Ki province is 650square meters per village and 2.19square meters per capita. and the relation between current rural-pocket park size and the number of household can be described as The current Size of Rural-Pocket Park = 7 ㎡${\times}$ Number of Households 2) The minimum size based on the rural residents'satisfaction is 633square meters at the 62 households level, and can be described as The Size of Rural-Pocket Park = 10㎡ ${\times}$ Number of Households 3) The most required activities by the rural residents are relaxation, children's playing and sports. and the most required facilities are ‘Jung-Ja’and ‘Combined Playing facility’. 4) The size required to include the basic recreational facilities at the level of household 20, 50, 100 are 132square meters. 386square meters, 633square meters respectively. The size per household is 7square meters and can be described as 5) As conclusion about 7square meters per household is recommended for the minimum size of rural-pocket park. and at least 140square meters is required as minimum size of rural-pocket park for the basic recreational facilities. The minimum Size of Rural-Pocket Park=㎡${\times}$Number of Households

• Journal of the Optical Society of Korea
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• v.18 no.3
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• pp.207-216
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• 2014

In this work, we report detailed numerical analysis of the near-elliptic core index-guiding triangular-lattice and square-lattice photonic crystal fiber (PCFs); where we numerically characterize the birefringence, single mode, cut-off behavior and group velocity dispersion and effective area properties. By varying geometry and examining the modal field profile we find that for the same relative values of $d/{\Lambda}$, triangular-lattice PCFs show higher birefringence whereas the square-lattice PCFs show a wider range of single-mode operation. Square-lattice PCF was found to be endlessly single-mode for higher air-filling fraction ($d/{\Lambda}$). Dispersion comparison between the two structures reveal that we need smaller lengths of triangular-lattice PCF for dispersion compensation whereas PCFs with square-lattice with nearer relative dispersion slope (RDS) can better compensate the broadband dispersion. Square-lattice PCFs show zero dispersion wavelength (ZDW) red-shifted, making it preferable for mid-IR supercontinuum generation (SCG) with highly non-linear chalcogenide material. Square-lattice PCFs show higher dispersion slope that leads to compression of the broadband, thus accumulating more power in the pulse. On the other hand, triangular-lattice PCF with flat dispersion profile can generate broader SCG. Square-lattice PCF with low Group Velocity Dispersion (GVD) at the anomalous dispersion corresponds to higher dispersion length ($L_D$) and higher degree of solitonic interaction. The effective area of square-lattice PCF is always greater than its triangular-lattice counterpart making it better suited for high power applications. We have also performed a comparison of the dispersion properties of between the symmetric-core and asymmetric-core triangular-lattice PCF. While we need smaller length of symmetric-core PCF for dispersion compensation, broadband dispersion compensation can be performed with asymmetric-core PCF. Mid-Infrared (IR) SCG can be better performed with asymmetric core PCF with compressed and high power pulse, while wider range of SCG can be performed with symmetric core PCF. Thus, this study will be extremely useful for designing/realizing fiber towards a custom application around these characteristics.

• 한국전산유체공학회:학술대회논문집
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• 2007.10a
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• pp.115-119
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• 2007

In this paper, a flow visualization analysis has been carried out on an oscillating square section cylinder, numerically, using a commercially available code CFD-ACE. In this study, the square cylinder is forced to oscillate at different frequencies of excitation, viz., fe/fo=0.5, 1.0 and 2.0 (where, fe is the excitation frequency provided to the cylinder and fo is the natural vortex shedding frequency from the stationary cylinder at a particular Reynolds number (=5200). In all the cases, the peak-to-peak amplitude of oscillation is kept at 32% of the side dimension of the square cylinder. These studies are conducted to understand the influence of frequency of oscillation on the flow field features around the cylinder, particularly the mode of vortex shedding. Results indicate that, the flow field around a square cylinder is very much influenced by the excitation frequency, in particular the vortex shedding mode. It is also found that, the vortex street parameters are significantly influence by the oscillation frequency. Comparison with earlier reported experimental studies has also been attempted in this paper. In appears that, such a numerical exercise (as performed in this paper) is first of its kind. It is believed that, these studies would enable one to understand the mechanisms underlying the flow-induced vibrations of a square section cylinder.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.24 no.1
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• pp.1-22
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• 2020

An accurate and efficient gradient estimation method on unstructured grid is presented by proposing a switching process between two Least-Square methods. Diverse test cases show that the gradient estimation by Least-Square methods exhibit better characteristics compared to Green-Gauss approach. Based on the investigation, switching between the two Least-Square methods, whose merit complements each other, is pursued. The condition number of the Least-Square matrix is adopted as the switching criterion, because it shows clear correlation with the gradient error, and it can be easily calculated from the geometric information of the grid. To illustrate switching process on general grid, condition number is analyzed using stencil vectors and trigonometric relations. Then, the threshold of switching criterion is established. Finally, the capability of Switching Weighted Least-Square method is demonstrated through various two- and three-dimensional applications.

• The Journal of Asian Finance, Economics and Business
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• v.5 no.1
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• pp.11-16
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• 2018

This research examines the alternative ways of estimating the coefficient of non-diversifiable risk, namely beta coefficient, in Capital Asset Pricing Model (CAPM) introduced by Sharpe (1964) that is an essential element of assessing the value of diverse assets. The non-parametric methods used in this research are the robust Least Trimmed Square (LTS) and Maximum likelihood type of M-estimator (MM-estimator). The Jackknife, the resampling technique, is also employed to validate the results. According to finance literature and common practices, these coecients have often been estimated using Ordinary Least Square (LS) regression method and monthly return data set. The empirical results of this research pointed out that the robust Least Trimmed Square (LTS) and Maximum likelihood type of M-estimator (MM-estimator) performed much better than Ordinary Least Square (LS) in terms of eciency for large-cap stocks trading actively in the United States markets. Interestingly, the empirical results also showed that daily return data would give more accurate estimation than monthly return data in both Ordinary Least Square (LS) and robust Least Trimmed Square (LTS) and Maximum likelihood type of M-estimator (MM-estimator) regressions.