• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2014.11a
• /
• pp.59-60
• /
• 2014

To prevent the rusting of steel, a variety of finishing materials has been applied. When steel is exposed to an extreme chloride environment, however, the thermal performance and aging of the finishing materials cause the material to lose its rust protective performance. In this study, an accelerated corrosion test was performed on five different finishing materials for steel, to determine the critical values of corrosion. As the result, the critical value of corrosion was found with no coat between 0.58mg/d㎡ and 0.73mg/d㎡, with urethane coat between 7.89mg/d㎡~8.46mg/d㎡, with one-layered red lead coat between 57.95mg/d㎡ and 69.48mg/d㎡, and with staleness201 between 80.73mg/d㎡ and 89.35mg/d㎡.

• Wind and Structures
• /
• v.1 no.2
• /
• pp.145-160
• /
• 1998

In recent years, the effects of a possible climate change have been discussed in regard to wind loading on buildings and structures. Simple scenarios based on the assumption of global warming suggest an increase of storm intensities and storm frequencies and a possible re-distribution of storm tracks. Among recent publications, some papers seem to verify these scenarios while others deny the influence of climatic change. In an introductory step, the paper tries to re-examine these statements. Based on meteorological observations of a weather station in Germany, the existence of long-term trends and their statistical significance is investigated. The analysis itself is based on a refined model for the wind climate introducing a number of new basic variables. Thus, the numerical values of the design wind loads used in modern codes become more justified from the probabilistic point of view.

• Wind and Structures
• /
• v.13 no.3
• /
• pp.257-273
• /
• 2010

The aerodynamic and aero-elastic model tests of the China''s highest cooling tower has been carried out in the TJ-3 Boundary Layer Wind Tunnel of Tongji University. By adopting a scanivalve system, the external wind pressure is firstly measured on $12{\times}36$ taps for a single tower, two and four grouped towers under the condition of both smooth flow and the boundary layer due to surrounding geographic and building topography. The measurements of internal wind pressure distribution of $6{\times}36$ taps are taken for a single tower under the various ventilation ratios ranging from 0% to 100% of stuffing layers located at the bottom of the tower. In the last stage, the wind tunnel tests with an aero-elastic model are carefully conducted to determine wind-induced displacements at six levels (each with eight points) with laser displacement sensors. According to the measurement results of wind pressure or vibration response, the extreme aerodynamic loading values of the single or grouped towers are accordingly analyzed based on probability correlation technique.

• The Korean Journal of Applied Statistics
• /
• v.11 no.2
• /
• pp.351-362
• /
• 1998

In this paper, a test of fit for Weibull distribution on the estimated Kullback-Leibler information is proposed. The test uses the Vasicek entropy estimates, so to compute it a window size m must first be fried, and then is obtained critical values computed by Monte Carlo simulations. The power of the proposed test under various alternatives is compares with that of ocher famous tests. The use of the test is shown in an illustrative example.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2002.05b
• /
• pp.1195-1204
• /
• 2002

The impacts of El Nino Southern Oscillation (ENSO) phenomenon on climate are widespread and extend far beyond the tropical Pacific. The phenomenon can be characterized by Southern Oscillation Index (SOI) which is derived from values of the monthly mean sea level pressure barometric difference between Tahiti and Darwin, Australia. Its best-known extreme is the El Nino event. In this study, general statistical characteristics of SOI and the data from which it is derived (i.e. mean sea level pressure data at Tahiti and Darwin) are presented as guidance when using SOI far other analyses. The characteristics include the availability of the barometric pressure data, statistics of monthly pressure data, correlation of SO intensity, frequency analysis of SOI by magnitude and by month (January-December), duration properties of SOI by run analysis.

• Journal of Drive and Control
• /
• v.13 no.1
• /
• pp.34-42
• /
• 2016

This study studied how the clearance, overlap and mismatch errors of spool-sleeve affect the static pressure characteristics of a servo valve. A computer simulation model was established as a direct acting servo valve and a series of simulations was conducted for various values of clearance, overlap and mismatch errors. Pressure gain decreased as the clearance increased. The overlap also affects the pressure gain and was similar to the effect of clearance. Asymmetry of the pressure plot got worse and worse as the mismatch error increased.

• Wind and Structures
• /
• v.21 no.4
• /
• pp.425-442
• /
• 2015

This paper discusses the processing of the wind loads measured in wind tunnel tests by means of multi-channel pressure scanners, in order to compute the response of 3D structures to atmospheric turbulence in the time domain. Data compression and the resulting computational savings are still a challenge in industrial contexts due to the multiple trial configurations during the construction stages. The advantage and robustness of the bi-orthogonal decomposition (BOD) is demonstrated through an example, a sail glass of the Fondation Louis Vuitton, independently from any tentative physical interpretation of the spatio-temporal decomposition terms. We show however that the energy criterion for the BOD has to be more rigorous than commonly admitted. We find a level of 99.95 % to be necessary in order to recover the extreme values of the loads. Moreover, frequency limitations of wind tunnel experiments are sometimes encountered in passing from the scaled model to the full scale structure. These can be alleviated using a spectral extension of the temporal function terms of the BOD.

• Journal of the Semiconductor & Display Technology
• /
• v.18 no.2
• /
• pp.63-66
• /
• 2019

Due to the development of medical imaging technology, different imaging technologies provide a large amount of effective information. However, different imaging method caused the limitations of information integrity by using single type of image. Combining different image together so that doctor can obtain the information from medical image comprehensively. Image registration algorithm based on mutual information has become one of the hotspots in the field of image registration with its high registration accuracy and wide applicability. Because the information theory-based registration technology is not dependent on the gray value difference of the image, and it is very suitable for multimodal medical image registration. However, the method based on mutual information has a robustness problem. The essential reason is that the mutual information itself is not have enough information between the pixel pairs, so that the mutual information is unstable during the registration process. A large number of local extreme values are generated, which finally cause mismatch. In order to overcome the shortages of mutual information registration method, this paper proposes a registration method combined with image spatial structure information and mutual information.

• Journal of the Korean Mathematical Society
• /
• v.32 no.4
• /
• pp.739-751
• /
• 1995

Let ${X(t) : 0 \leq t < \infty}$ be an almost surely continuous Gaussian process with X(0) = 0, E{X(t)} = 0 and stationary increments $E{X(t) - X(s)}^2 = \sigma^2($\mid$t - s$\mid$)$, where $\sigma(y)$ is a function of $y \geq 0(e.g., if {X(t);0 \leq t < \infty}$ is a standard Wiener process, then $\sigma(t) = \sqrt{t})$. Assume that $\sigma(t), t > 0$, is a nondecreasing continuous, regularly varying function at infinity with exponent $\gamma$ for some $0 < \gamma < 1$.

• Communications for Statistical Applications and Methods
• /
• v.30 no.3
• /
• pp.245-258
• /
• 2023

This study proposes a modification to the objective function of the support vector machine for the linearly non-separable case of a binary classifier y_i ∈ {-1, 1}. The modification takes into account the position of each data item x_i from its corresponding class centroid. The resulting optimization function involves the centroid mean vector, and the spread of data besides the support vectors, which should be minimized by the choice of hyper-plane β. Theoretical assumptions have been tested to derive an optimal separable hyperplane that yields the minimal misclassification rate. The proposed method has been evaluated using simulation studies and real-life COVID-19 patient outcome hospitalization data. Results show that the proposed method performs better than the classical linear SVM classifier as the sample size increases and is preferred in the presence of correlations among predictors as well as among extreme values.