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China, situated in the circum-Pacific seismic belt, experiences frequent seismic activity and faces diverse geological conditions, making structural stability of paramount importance, especially under seismic conditions. The majority of current earthquake generation methods do not consider the nonstationary nature of earthquakes. This paper introduces a spectral representation-random function model for generating nonstationary earthquakes, effectively simulating stochastic seismic ground motion. Furthermore, traditional slope stability analysis methods are deterministic and incapable of providing probabilistic assessments of slope instability. Therefore, this paper proposes a unified framework for static and dynamic structural reliability analysis based on the direct probability integration method, quantifying the impact of stochastic seismic ground motion on the dynamic reliability of slope stability. Finally, the proposed methods are applied to an excavation slope in Nanjing, using sliding displacement and safety factors as evaluation criteria to study the reliability of the slope under the influence of stochastic seismic events. [ABSTRACT FROM AUTHOR]

The application of a sodium laser guide star is the key difference between a modern adaptive optics system and traditional adaptive optics system. Especially in system such as multiconjugate adaptive optics, a sodium laser guide star asterism that is formed by several laser guide stars in a certain pattern is required to probe more atmospheric turbulence in different directions. To achieve this, a sodium laser guide star asterism launching platform is required. In this paper, we introduce the sodium laser guide star asterism launching platform built and tested on the 1.8 m telescope of Gaomeigu Observatory. The platform has two functions: one function is to compare the performance of sodium laser guide stars generated by different lasers at the same place, and the other function is to generate a sodium laser guide star asterism with an adjustable shape. The field test results at the beginning of 2021 verified the important role of the platform, which is also the first time that a sodium laser guide star asterism was realized in China. [ABSTRACT FROM AUTHOR]

Today, earnings mismanagement in China's enterprises has become a serious problem as managers conduct financial fraud by means of earnings management, hindering China's overall economic development. Upon shareholders' requirements and investors' concerns, managers should disclose real financial information. The essay analyzes the revenue function generated by the manager and the shareholder through an evolutionary theory model where the managers team of the enterprise and shareholders are both game parties. After building the model, the essay utilizes Python to stimulate the theoretical model to analyze both parties' behavior to explain the process of evolutionary game theory. [ABSTRACT FROM AUTHOR]

Since entering the 'Millennium of the cities' omnipresent rapid urbanization has caused dramatic changes to ecosystem functions and generated huge ecological risks across city catchments. An understanding of how multiple ecosystem services are associated across complex social-ecological systems is required for urban sustainability. However, few studies have explored how the trade-offs and synergies of ecosystem service response to the traits of urbanization processes such as the variation of undeveloped-developed continuum. In this study, we took the Yangtze River Delta in China, a typical megapolis, as the case study area and quantified seven ecosystem services at a 10 km x 10 km spatial scale. We presented the spatial distribution and interactions of these services and identified whether they coexist in the form of specific cluster types. We found positive spatial autocorrelations across the study site. A significant tendency of trade-offs was detected between regulating and agricultural provisioning services, and we also spotted the possibility of both trade-offs and synergies that regulating and (different) cultural services were able to provide. Our results identified four different cluster types, and the cluster distributions are strongly associated with the urbanization levels—a tendency for urbanizing areas to witness the function shift in the certain order of 'ecology – provision – multifunction – accessibility'. This provides a deeper understanding of the interactions among multiple ecosystem services and how they were determined by the ongoing social-ecological influences. The close connection between urbanization processes and ecosystems interact across developing and developed areas should be taken into consideration for future landscape planning. [ABSTRACT FROM AUTHOR]

In recent years, the stationary assumption of hydroclimatic variables as well as their temporal and spatial dependence structure have been challenged due to anthropogenic and climate changes. This study developed a stepwise and dynamic C-vine copula–based conditional model (SDCVC) to incorporate the nonstationarity into a monthly streamflow prediction, which depicted the predictor–predictand association on the basis of monthly streamflow and rainfall series of upstream and downstream stations in the Yangtze River basin of China. The model consists of (1) nonstationary modeling of the margins and nonstationary temporal and spatial dependence structure by the generalized additive models with location, scale, and shape (GAMLSS) and C-vine copula incorporating climate-related indexes as covariates during training time frames; and (2) a four-dimensional C-vine copula–based conditional quantile function to generate the simulated series during validation time frames. Three kinds of nonstationary models corresponding to different degrees were investigated to show the impact of nonstationarity on the streamflow forecasting. The proposed SDCVC model considering highest degree of nonstationarity outperformed the other two nonstationary models in terms of the performance metrics, because the SDCVC model not only described the dynamic change of time-varying connections between parameter and the large-scale climate forcings, but the stepwise strategy, by selecting the optimum time horizon, helped increase forecasting accuracy. Furthermore, the SDCVC model is superior, to some extent, to classical data-driven approaches [support vector regression (SVR) and adaptive-network-based fuzzy inference system (ANFIS)] in terms of the performance metrics. [ABSTRACT FROM AUTHOR]

The aim of this study is to analyze the number of deaths due to COVID-19 for Europe and China. For this purpose, we proposed a novel three parametric model named as Exponentiated transformation of Gumbel Type-II (ETGT-II) for modeling the two data sets of death cases due to COVID-19. Specific statistical attributes are derived and analyzed along with moments and associated measures, moments generating functions, uncertainty measures, complete/incomplete moments, survival function, quantile function and hazard function, etc. Additionally, model parameters are estimated by utilizing maximum likelihood method and Bayesian paradigm. To examine efficiency of the ETGT-II model a simulation analysis is performed. Finally, using the data sets of death cases of COVID-19 of Europe and China to show adaptability of suggested model. The results reveal that it may fit better than other well-known models. [ABSTRACT FROM AUTHOR]

• This study developed a dynamic copula-based simulation model (DCSM) to single-site seasonal rainfall generation. • The climate-related nonstationarity-based bivariate conditional model would help to predict rainfall for the next season. • Consideration of the nonstationarity would improve the performance of simulation accuracy. In recent years, anthropogenic and climate changes have greatly impacted the probabilistic behavior of hydrometeorological variables, and have challenged the stationarity assumption of marginal distributions of individual characteristics of variables as well as their temporal dependence structure inherent in copula-based modelling. This study developed a dynamic copula-based simulation model (DCSM) for single-site seasonal rainfall generation, observed at Beijing Station in Haihe River basin, China. The model entailed four phases: (1) nonstationary modelling of the margins by the Generalized Additive Models for Location, Scale and Shape (GAMLSS); (2) dynamical copula method to describe the nonstationary temporal dependence structure of rainfall observed at adjacent two seasons; (3) a dynamic copula-based conditional quantile function to generate simulated series; (4) performance assessment of the simulated series by the proposed DCSM model with the preservation of basic statistics of each sequence and simulation accuracy at each data point. Comparison of the nonstationary and stationary models to simulate the seasonal rainfall series shows that the incorporation of nonstationarity in hydrometeorological simulation would improve the performance of simulation accuracy. [ABSTRACT FROM AUTHOR]

The large-scale cascade hydropower plants in southwestern China now challenge a multi-market environment in the new round of electricity market reform. They not only have to supply the load for the local provincial market, but also need to deliver electricity to the central and eastern load centers in external markets, which makes the generation scheduling much more complicated, with a correlated uncertain market environment. Considering the uncertainty of prices and correlation between multiple markets, this paper has proposed a novel optimization model of long-term generation scheduling for cascade hydropower plants in multiple markets to seek for the maximization of overall benefits. The Copula function is introduced to describe the correlation of stochastic prices between multiple markets. The price scenarios that obey the Copula fitting function are then generated and further reduced by using a scenario reduction strategy that combines hierarchical clustering and inconsistent values. The proposed model is applied to perform the long-term generation scheduling for the Wu River cascade hydropower plants and achieves an increase of 106.93 million yuan of annual income compared with the conventional scheduling model, without considering price scenarios, showing better performance in effectiveness and robustness in multiple markets. [ABSTRACT FROM AUTHOR]