Residential comfort assessment due to blasting vibration

Blasting operation usually causes vibration to adjacent buildings and adversely impacts the residential comfort of residents, and the resulting disturbance to residents may lead to the occurrence of disputes and complaints against such problems. In this study, the blasting vibration acceleration is calculated based on the measured blasting vibration velocity signal using the four-point forward difference method. The Infinite Impulse Response (IIR) digital filter is applied for frequency weighting of acceleration, so as to calculate the comfort index; the vibration dose value (VDV) method is adopted to evaluate the vibration comfort and impact of blasting operation. Combined with engineering cases analyses, it is found that even small blasting vibrations which are insufficient to cause building damage might result in residents’ grumbles or complaints, and thus we suggests that the comfort of blasting vibration be taken into account during blasting operations

Model-based Offline Policy Optimization with Adversarial Network

Model-based offline reinforcement learning (RL), which builds a supervised transition model with logging dataset to avoid costly interactions with the online environment, has been a promising approach for offline policy optimization. As the discrepancy between the logging data and online environment may result in a distributional shift problem, many prior works have studied how to build robust transition models conservatively and estimate the model uncertainty accurately. However, the over-conservatism can limit the exploration of the agent, and the uncertainty estimates may be unreliable. In this work, we propose a novel Model-based Offline policy optimization framework with Adversarial Network (MOAN). The key idea is to use adversarial learning to build a transition model with better generalization, where an adversary is introduced to distinguish between in-distribution and out-of-distribution samples. Moreover, the adversary can naturally provide a quantification of the model's uncertainty with theoretical guarantees. Extensive experiments showed that our approach outperforms existing state-of-the-art baselines on widely studied offline RL benchmarks. It can also generate diverse in-distribution samples, and quantify the uncertainty more accurately.Comment: Accepted by 26th European Conference on Artificial Intelligence ECAI 202

Multi-Agent Game Abstraction via Graph Attention Neural Network

In large-scale multi-agent systems, the large number of agents and complex game relationship cause great difficulty for policy learning. Therefore, simplifying the learning process is an important research issue. In many multi-agent systems, the interactions between agents often happen locally, which means that agents neither need to coordinate with all other agents nor need to coordinate with others all the time. Traditional methods attempt to use pre-defined rules to capture the interaction relationship between agents. However, the methods cannot be directly used in a large-scale environment due to the difficulty of transforming the complex interactions between agents into rules. In this paper, we model the relationship between agents by a complete graph and propose a novel game abstraction mechanism based on two-stage attention network (G2ANet), which can indicate whether there is an interaction between two agents and the importance of the interaction. We integrate this detection mechanism into graph neural network-based multi-agent reinforcement learning for conducting game abstraction and propose two novel learning algorithms GA-Comm and GA-AC. We conduct experiments in Traffic Junction and Predator-Prey. The results indicate that the proposed methods can simplify the learning process and meanwhile get better asymptotic performance compared with state-of-the-art algorithms.Comment: Accepted by AAAI202

Survey on the influencing factors of human comfort in a long-period frequent blast vibration environment

Blasting operation exerts adverse effects on the vibration comfort of nearby buildings and structures, and causes a number of civil complaints, discomfort and even lawsuits. Blasting vibration comfort is related not only to the vibration characteristics of blasting and buildings, but also to the non-blasting factors such as, (i) the gender, age, income, psychology, and educational background of the subjects, (ii) the environment they are in, and (iii) the activities in which they are engaged. Based on typical multi-year frequent blasting work cases, three groups of people are selected, and Likert scale method is used to design a detailed comfort survey plan. After tracking, monitoring and surveying over several years, 168 groups of survey data are obtained. The survey results show that, there is a nonlinear relationship between human comfort and blasting vibration amplitude. Moreover, compared with the peak particle vibration velocity (PPV), the absorbed blasting vibration energy (ABVE) index can better reflect the influence of blasting vibration factors. Difference in human comfort between different groups of people and its causes are analyzed. The correlation analysis results show that the correlation coefficients between vibration comfort and four factors (blasting noise, environmental noise, environmental vibration and ongoing activities) range from 0.28 to 0.34. Finally, combining the statistical analysis results, six factors exerting a relatively significant influence on comfort are determined. The outcomes are expected to provide a basis for eventually establishing a multi-level and multi-factor quantitative evaluation model for blasting vibration comfort

Kinetic Study on the Isothermal and Nonisothermal Crystallization of Monoglyceride Organogels

The isothermal and nonisothermal crystallization kinetics of monoglyceride (MAG) organogels were studied by pulsed nuclear magnetic resonance (pNMR) and differential scanning calorimetry (DSC), respectively. The Avrami equation was used to describe the isothermal crystallization kinetics and experimental data fitted the equation fairly well. Results showed that the crystal growth of MAG organogels was a rod-like growth of instantaneous nuclei at higher degrees of supercooling and a plate-like form with high nucleation rate at lower degrees of supercooling. The exothermic peak in nonisothermal DSC curves for the MAG organogels became wider and shifted to lower temperature when the cooling rate increased, and nonisothermal crystallization was analyzed by Mo equation. Results indicated that at the same crystallization time, to get a higher degree of relative crystallinity, a higher cooling rate was necessary. The activation energy of nonisothermal crystallization was calculated as 739.59 kJ/mol according to the Kissinger method. Therefore, as the results of the isothermal and nonisothermal crystallization kinetics for the MAG organogels obtained, the crystallization rate, crystal nucleation, and growth during the crystallization process could be preliminarily monitored through temperature and cooling rate regulation, which laid the foundation for the real industrial manufacture and application of the MAG organogels

Comparative analysis on the comfort assessment methods and standards of blasting vibration

The seismic effect created by blasting operations vibrates adjacent buildings and disturbs residents living in these buildings, often leading to disputes and complaints. In this paper, the vibration acceleration was calculated based on the measured blasting vibration velocity using the wavelet denoising-based four-point forward difference method. The infinite impulse response (IIR) digital filter was used to obtain the frequency weighting of acceleration, so as to calculate comfort assessment indexes such as vibration dose value (VDV), maximum weighted vibration severity (KBFmax) and annoyance rate. Combined with the survey of engineering cases, comparative analysis was conducted on the indexes and standards that were suitable for the comfort assessment of blasting vibration. The results indicated that VDV, KBFmax, and annoyance rate indexes could all reflect the impact of blasting vibration on comfort to a certain extent, and that while the first two indexes could only be used for qualitative assessment, the annoyance rate index could be used for quantitative comfort assessment. In addition, by applying these assessment indexes for the comfort assessment of blasting vibration, preliminary control standards were provided

Residential comfort assessment due to blasting vibration

Blasting operation usually causes vibration to adjacent buildings and adversely impacts the residential comfort of residents, and the resulting disturbance to residents may lead to the occurrence of disputes and complaints against such problems. In this study, the blasting vibration acceleration is calculated based on the measured blasting vibration velocity signal using the four-point forward difference method. The Infinite Impulse Response (IIR) digital filter is applied for frequency weighting of acceleration, so as to calculate the comfort index; the vibration dose value (VDV) method is adopted to evaluate the vibration comfort and impact of blasting operation. Combined with engineering cases analyses, it is found that even small blasting vibrations which are insufficient to cause building damage might result in residents’ grumbles or complaints, and thus we suggests that the comfort of blasting vibration be taken into account during blasting operations