There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

System Identification I

Dynamics of structures

: This thesis applies neural network feature selection techniques to multivariate time series data to improve prediction of a target time series. Two approaches to feature selection are used. First, a subset enumeration method is used to determine which financial indicators are most useful for aiding in prediction of the S&P 500 futures daily price. The candidate indicators evaluated include RSI, Stochastics and several moving averages. Results indicate that the Stochastics and RSI indicators result in better prediction results than the moving averages. The second approach to feature selection is calculation of individual saliency metrics. A new decision boundary-based individual saliency metric, and a classifier independent saliency metric are developed and tested. Ruck's saliency metric, the decision boundary based saliency metric, and the classifier independent saliency metric are compared for a data set consisting of the RSI and Stochastics indicators as well as delayed closing price values. The decision based metric and the Ruck metric results are similar, but the classifier independent metric agrees with neither of the other metrics. The nine most salient features, determined by the decision boundary based metric, are used to train a neural network and the results are presented and compared to other published results. (AN)

/pdf/nonlinear-time-series-analysis-1j3a35n4y3.pdf

Nonlinear Time Series Analysis.

Feasibility investigations on wind power generation on top of super-tall buildings

This paper aims to systematically study the across-wind loads of rectangular-shaped tall buildings with aerodynamic modifications and propose refined mathematic models accordingly. This study takes...

Refined Mathematical Models for Across-Wind Loads of Rectangular Tall Buildings with Aerodynamic Modifications

A generalised finite segment method for the analysis of a skewed multi-rib T-beam is presented in this paper. Using the skewed beam element under an inclined coordinate system for the skewed deck and normal beam element for the ribs, a spatial displacement field for the composite structure is constructed. Shear lag effect and local flexure of the deck are taken into consideration in constructing the displacement field, as well as the stiffness of the transverse diaphragm. The formulation of the finite segment is established based on the variational principle. The proposed method simplifies a three-dimensional structure into a one-dimensional structure such as a beam for structural analysis and therefore reduces the computational efforts significantly. Numerical examples are given to illustrate the application of the proposed approach. It is shown through the examples that the results obtained using the proposed finite segment approach are in agreement with the experimental data, verifying the accuracy of ...

A spatial displacement model for skewed multi-rib T-beams

This paper introduces a new connection－inner and through-type diaphragm, which is recommended by Technical Specification for Structures with Concrete-filled Rectangular Steel Tube Members. It studies some factors including the additional plates installed on both sides of the flanges, the width-to-thickness ratio of the column and the length of the through diaphragm which have an influence to the seismic resistance behaviors of connection through cyclic test. The results show the hysteresis curves attained in the experiment are full and the rigidity deterioration is not obvious. The connection models have a good energy dissipation capacity. Meanwhile the stress distributing can be ameliorated and the ductility of the connections can also be improved through welding the additional plates to both sides of the flanges.

http://www.iitk.ac.in/nicee/wcee/article/14_05-05-0009.PDF

Qiusheng Li

Papers

Feasibility investigations on wind power generation on top of super-tall buildings

Refined Mathematical Models for Across-Wind Loads of Rectangular Tall Buildings with Aerodynamic Modifications

A spatial displacement model for skewed multi-rib T-beams

Experimental Studies on Seismic Behavior of Concrete-Filled Steel Square Tubular Column-Steel Beam Connection

Comparative study between field measurements of wind pressures on a 600-m-high skyscraper during Super Typhoon Mangkhut and wind tunnel test