Damage Identification under Incomplete Mode Shape Data Using Optimization Technique Based on Generalized Flexibility Matrix

A generalized flexibility–based objective function utilized for structure damage identification is constructed for solving the constrained nonlinear least squares optimized problem. To begin with, the generalized flexibility matrix (GFM) proposed to solve the damage identification problem is recalled and a modal expansion method is introduced. Next, the objective function for iterative optimization process based on the GFM is formulated, and the Trust-Region algorithm is utilized to obtain the solution of the optimization problem for multiple damage cases. And then for computing the objective function gradient, the sensitivity analysis regarding design variables is derived. In addition, due to the spatial incompleteness, the influence of stiffness reduction and incomplete modal measurement data is discussed by means of two numerical examples with several damage cases. Finally, based on the computational results, it is evident that the presented approach provides good validity and reliability for the large and complicated engineering structures.

Evaluating the Impacts of Food Safety Policies on Japan's Rice Imports Based on the Simultaneous Buy and Sell System

This study evaluated the impacts of food safety policies on Japan's Simultaneous Buy and Sell rice imports through measuring tariff equivalents of food safety policies.In order to construct an estimated model,a Japanese consumer's utility function is introduced and developed with consumer's preference parameters and elasticity of substitution.In the empirical study part,Japan's positive list system and rice traceability were analyzed and assessed as critical food safety policies.Results showed that after the implementation of the positive list system,consumers'preference for foreign rice and the substitution elasticity diminished.This decreasing tendency was quite similar to the results after the enforcement of rice traceability.The tariff equivalents of food safety policies on imported rice fluctuated around ¥50 yen/kg from fiscal year 2000 to 2005 and decreased because of the global grain price hike after 2006.The tariff equivalents soared in 2010,which was induced by the traceability regulation,and then dulled during Japan's earthquake and tsunami in 2011.Subsequently,after the recovery from natural disasters,the tariff equivalents of food safety policies became higher.Therefore,food safety policies had made imported rice less attractive,weakened the competitive power of rice exporting countries,and had statistically significant impacts on Japan's rice importation.