• Wind and Structures
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• v.35 no.6
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• pp.369-383
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• 2022

Wind tunnel experiment was carried out to study the cross-wind layer forces on a square cross-section building model using a synchronous multi-pressure sensing system. The stationarity of measured wind loadings are firstly examined, revealing the non-stationary feature of cross-wind forces. By converting the measured non-stationary wind forces into an energetically equivalent stationary process, the characteristics of local wind forces are studied, such as power spectrum density and spanwise coherence function. Mathematical models to describe properties of cross-wind forces at different layers are thus established. Then, a conditional simulation method, which is able to ex-tend pressure measurements starting from experimentally measured points, is proposed for the cross-wind loading. The method can reproduce the non-stationary cross-wind force by simulating a stationary process and the corresponding time varying amplitudes independently; in this way the non-stationary wind forces can finally be obtained by combining the two parts together. The feasibility and reliability of the proposed method is highlighted by an ex-ample of across wind loading simulation, based on the experimental results analyzed in the first part of the paper.

• Wind and Structures
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• v.26 no.5
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• pp.331-341
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• 2018

A numerical study on the flow over a square cylinder in the vicinity of a wall is conducted for different Couette-Poiseuille-based non-uniform flow with the non-dimensional pressure gradient P varying from 0 to 5. The non-dimensional gap ratio L (=$H^{\ast}/a^{\ast}$) is changed from 0.1 to 2, where $H^{\ast}$ is gap height between the cylinder and wall, and $a^{\ast}$ is the cylinder width. The governing equations are solved numerically through finite volume method based on SIMPLE algorithm on a staggered grid system. Both P and L have a substantial influence on the flow structure, time-mean drag coefficient ${\bar{C}}_D$, fluctuating (rms) lift coefficient ($C_L{^{\prime}}$), and Strouhal number St. The changes in P and L leads to four distinct flow regimes (I, II, III and IV). Following the flow structure change, the ${\bar{C}}_D$, $C_L{^{\prime}}$, and St all vary greatly with the change in L and/or P. The ${\bar{C}}_D$ and $C_L{^{\prime}}$ both grow with increasing P and/or L. The St increases with P for a given L, being less sensitive to L for a smaller P (< 2) and more sensitive to L for a larger P (> 2). A strong relationship is observed between the flow regimes and the values of ${\bar{C}}_D$, $C_L{^{\prime}}$ and St. An increase in P affects the pressure distribution more on the top surface than on bottom surface while an increase in L does the opposite.

• Korean Journal of Biological Psychiatry
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• v.21 no.4
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• pp.141-150
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• 2014

Objectives The purpose of this study is to evaluate the effects of attachment security, social support and health-related burden in the prediction of psychological distress and the mediation effects of social support and health-related burden in relationship between attachment security and psychological distress. Methods Finally, 161 patients were included for the analysis. Chi-square test and independent samples t-test were used for comparing differences between depressive/anxious group and non-depressive/non-anxious group. For evaluating the relationship among attachment security, social support, psychological distress and health-related burden, structural equation modeling analysis were performed. Results 40.7% and 32.0% of the patients have significant depressive symptoms and anxiety symptoms, respectively. In the analysis for testing the differences between groups who have psychological distress and who have not, there were no significant differences of sociodemographic factors and medical characteristics between groups, except for association between depressive symptoms and type of surgery (p = 0.01). Contrary to sociodemographic and medical characteristics, there were significant differences of health-related burden and two coping resources (attachment security and social support) between groups (all p < 0.01), except for the support from medical team in between anxious group and non-anxious group (p = 0.20). In the structural equation model analysis (Model fit : chi-square/df ratio = 0.8, root mean square error of approximation = 0.000, comparative fit index = 1.000, non-normed fit index =0.991), attachment security and social support emerged as an important predictor of psychopathology. Conclusions Attachment security and social support are important factors affecting the psychological distress. We suggest that individual attachment style and the social support state must be considered to approach the newly diagnosed breast cancer patients with psychological distress.

• Communications of Mathematical Education
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• v.24 no.1
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• pp.195-220
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• 2010

The magic square is one of the number arrangements and the sums of each row, column, and diagonal are all equal. The meaning of "方" is "Square". If we don't consider the condition of 'square' then is it possible any number arrangement? There are many special number arrangements such as "magic five number circle(緊五圖)", "magic six number circle(聚六圖)", "magic eight number circle(聚八圖)", "magic nine number circle(攢九圖)", "magic eight camp circle(八陣圖)", "magic nine camp circle(連環圖)" in the ancient Chinese mathematics books such as "楊輝算法", "算法統宗". Also, there is a very special and beautiful number arrangement Jisuguimoondo(地數龜文圖) in the mathematics book "Goosuryak(九數略)" written by Choi suk jung(崔錫鼎) in the Joseon Dynasty. In this study, we introduce a various number arrangements and their properties.

• Science of Emotion and Sensibility
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• v.24 no.4
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• pp.29-38
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• 2021

Korean typefaces are characterized on two axes: a font is either serifed or non-serifed, and it is either square-frame or non-squared. A serifed font entails small strokes that are regularly attached to the ends of larger strokes. Conversely, fonts without these marks are termed sans-serif. One of the exclusive features of Korean typeface of the square-frame type is that in such fonts, vowels and consonants often with their final vowels, are harmonically placed within the boundaries of the virtual square. We hypothesize that serifed and squared-frame typefaces are more popular and preferred owing to their widespread use throughout history. A survey incorporating Korean pangrams written with serif, sans-serif, squared, and non-squared typefaces was designed to test the present hypothesis. We found that people typically preferred and were more familiar with squared typefaces compared to non-squared typefaces. However, no difference was observed between serifed and san-serif typefaces. Furthermore, a positive correlation was found between familiarity and preference ratings only where the typefaces had squared and serifed features. The results revealed that Korean typefaces with the squared feature were more well-known and, therefore, more preferred to the typefaces without it. The results further indicated that Korean typefaces with the squared feature can be recommended for people's familiarity to it and the comfort it provides, and their emotional relevance and sensibility enhanced if serifs are added.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.1
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• pp.29-37
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• 2012

This paper is concerned with the natural vibration characteristics of a rectangular plate with a rectangular hole in contact with the water. The addressed problem was solved by using the Rayleigh-Ritz method combined with the Green function method. This study presents the numerical approach, numerical results and experimental results. In addition, the validity of the approximate formula which mainly depends on the so-called non-dimensionalized added virtual mass incremental factor and the natural mode shape change due to the presence of the water were investigated. Experiments were also carried out to validate theoretical results. The theoretical results are in good agreement with the experimental results. It was found that the effect of a square hole on the natural frequencies of the square plate in contact with water is different from the effect of a square hole on the natural frequencies of the square plate in air and the approximate formula can predict lower natural frequencies in water with a good accuracy.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1995.10a
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• pp.150-156
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• 1995

In the finite element analysis of metal forming processes, the updated Lagrangian approach has been widely and effectively used to simulate the non-steady state problems. However some difficulties have arisen from abrupt flow change as in extrusion through square dies. In the present work, a ALE(arbitrary Lagrangian-Eulerian) finite element formulation for deformation analysis are presented for rigid viscoplastic materials. The developed finite element program is applied to the analysis of square die extrusion of a square section. The computational results are compared with those from the updated Lagrangian finite element analysis.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.118-121
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• 2005

The square cup drawing of magnesium alloy AZ31 $(aluminum\;3\%,\;Zinc\;1\%)$ sheets was studied by experimental approach in various temperatures (200, 250, 300, 350, $400^{\circ}C$) when blank holding force (BHF) was controlled in real-time. And so on, the drawability was measured with the different die and punch coating. The square cup drawing test was performed by three different coated punches (CrN, TiCN, Non-coated). BHF was set about 2.0 KN, forming speed was 50 mm/min, blank thickness were 0.5, 1.0mm and the cup size was 40 mm by 60 mm after forming. The experimental data of square cup drawing test show that the tools coating and temperature were effect on the drawbility.

• Journal of information and communication convergence engineering
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• v.19 no.4
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• pp.269-275
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• 2021

Light-emitting diodes (LEDs) are modulated using a square wave pulse sequence for flicker prevention and dimming control in visible light communication (VLC). In a VLC transmitter, the high and low bits of the non-return-to-zero (NRZ) data are converted to two square waves of different frequencies, which continue for a finite time defined by the fill ratio in an NRZ bit time. As the average optical power was kept constant and independent of data transmission, the LED was flicker-free. Dimming control is carried out by changing the fill ratio of the square wave in the NRZ bit time. In the experiments, the illumination of the LED light was controlled in the range of approximately 19.2% to 96.2% of the continuous square wave modulated LED light. In the VLC receiver, a high-pass filter combined with a latch circuit was used to recover the transmitted signal while preventing noise interference from adjacent lighting lamps.

• Journal of Korean Society of Steel Construction
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• v.18 no.5
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• pp.525-534
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• 2006

Column-to-beam pinned connections can cause local moment to the web of a steel tube due to the distance of eccentricity between the row of bolts and the column flange, which possibility deteriorates the load capacity of column. In this study, a square hollow section tubular used finite element analysis of a square hollow section tubular column was carried out, and the column width and thickness, existence and non-existence of internal reinforcement, and existence and non-existence of compressive force were taken as variables to examine the load capacity deterioration of a square column caused by moment. To guarantee the reliability of the finite element results, some specimens were fabricated and tested. The yield line method was applied to suggest the strength formulas of the square tubular column to the beam pinned connections. Based on the study results, the column strength the moment of the square hollow section tubular column to the beam pined connections improved with the increase in the w to strength limitations, a no-reinforcement type of square hollow section tubular column was proposed, and if the limitation values were not satisfied, the reinforcement of the internal column was made mandatory. Therefore, the horizontal -reinforcement type considered the strength increase, and the fabrication of the square hollow section tubular column was ar column that considered its load capacity with the moment for the no-reinforcement and the horizontal-reinforcement types.