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When dealing with simple functional functions, traditional reliability calculation methods, such as the linear second-order moment and quadratic second ordered moment, Monte Carlo simulation method, are powerful. However, when the functional function of the structure shows strong nonlinearity or even implicit, traditional methods often fail to meet the actual needs of engineering in terms of calculation accuracy or efficiency.

To improve the reliability analysis efficiency and calculation accuracy of complex structures, the reliability analysis methods based on parametric and semi-parametric models are analyzed.

This paper proposes a reliability method that combines the Kriging model and the importance sampling method to improve the calculation efficiency of traditional reliability analysis methods.

This method uses an active learning function and introduces an importance sampling method to screen sample points and shift the center of gravity, thereby reducing the sample size and the amount of calculation.

Ancient city walls are typical linear space elements of Beijing that represent the transformation of urban form over the past 800 years and have greatly influenced the memory of the entire city. However, recently, most of the walls have been torn down in the process of fast urbanization and old city renewal. The purpose of this paper is to focus on people’s cognition and evaluation of urban memory during this pull-down-and-preserve process.

A sample of 380 participants was investigated on a number of issues using questionnaires, including memory case reminders (stability, variability, temporality), emotional bonding with memory case (identity, dependence, authenticity), and socio-demographic variables (age, education, life experience, length of residence). The urban memory cognition model and attitude evaluation value model which were based on Likert scale were used to process the collected data.

In the three aspects of memory case reminders, stability and temporary elements can be most cognized, whereas variability elements are more difficult due to their change over time. As for emotional bonding with memory case, people show a high level of identification with the walls; the walls’ memory being passed down could enhance people’s memory when mentioning Beijing. Further, higher education groups consider the walls’ authenticity to be most important and are unwilling to accept the outcome of walls-ruins parks; older adults have tolerant attitudes to the ruins parks.

This study could not only contribute to the excavation of urban memory, but also strengthen citizens’ sense of identity and cohesiveness, thus shaping the spirit and culture of the city. Some findings could provide applicable guidelines for urban heritage protection and contribute a new perspective on the interrelationship between people and their physical surroundings.