Search Results (12)

This work explores the implications of assuming time symmetry and applying bridge-type, time-symmetric temporal boundary conditions to deterministic laws of nature with random components. The analysis, drawing on the works of Kolmogorov and Anderson, leads to two forms of governing equations, referred to here as symmetric and antisymmetric. These equations account for the emergence of characteristics associated with conventional thermodynamics, the arrow of time, and a form of antecedent causality. The directional properties of time arise from the mathematical structure of Markov bridges in proximity of the corresponding temporal boundary conditions, without requiring any postulates that impose a preferred direction of time. Full article

Exploring the path of energy structure optimization to reduce carbon emissions and achieve a carbon peak has important policy implications for achieving the “Dual Carbon” target. To this end, this paper explores the optimal path for China to achieve the “dual carbon” target from the perspective of energy structure optimization in three steps: (1) we forecast China’s carbon emissions and carbon intensity during 2024–2035 based on a combined forecasting model; (2) we simulate the development of energy consumption and carbon emissions under the “economic development scenario-energy structure scenario” with the help of Markov chain forecasting model; (3) we construct a multi-attribute decision model to account for the above elements as variables to calculate a composite index to analyze the optimal path for China to achieve “Dual Carbon” target under different decision preferences. It is found that (1) potential negative effects caused by COVID-19 are not as serious as reported; (2) only the scenario with low-speed economic growth and effective policies guiding, which doesn’t follow laws of social development, can contribute to reaching carbon peaking by 2030 while maintaining a high-quality carbon intensity; (3) the optimal path that scenario with middle-speed economic growth and strict cost control is a sub-optimal choice subject to realities; (4) technologies innovations in green or low-carbon fields are needed to accelerate energy consumption structure optimization. Full article

This paper generalizes the structural Markov properties for undirected decomposable graphs to arbitrary ones. This helps us to exploit the conditional independence properties of joint prior laws to analyze and compare multiple graphical structures, while being able to take advantage of the common conditional independence constraints. This work provides a theoretical support for full Bayesian posterior updating about the structure of a graph using data from a certain distribution. We further investigate the ratio of graph law so as to simplify the acceptance probability of the Metropolis–Hastings sampling algorithms. Full article

The research conducted in this paper aims to appraise the interlinkages between public governance and digital transformation at the level of the European Union. We employ two advanced approaches to modelling longitudinal data compiled at the level of the EU-27 Member States during the 2010–2021 period, namely, structural equation modelling and Gaussian and Mixed-Markov graphical models. The main results indicate positive impacts on government effectiveness arise from the human capital involved in complex activities that engage the use of digital services, e-government users, and integration of digital technologies, and the effect of demands and supplies of digital public services using open data. This further supports the government’s capabilities in enforcing regulations and policies to control corruption and sustain the achievement of digital skills, at least at a basic level, by the entire society. Moreover, good perceptions and a higher degree of confidence in the rules of law have a positive influence on the need for connectivity of digital services, especially the supply side of fixed and mobile broadband. Lastly, a relevant impact of regulatory quality is identified in the digital connectivity of broadband infrastructure, which is enclosed by the public governance representative indicators under the influence of a stronger integration of digitalisation. Full article

In this study, we analyse a large sample of Egyptian social pension data which covers, by law, the policyholder’s spouse, children, parents and siblings. This data set uniquely enables the study and comparison of pairwise dependence between multiple familial relationships beyond the well-known husband and wife case. Applying Bayesian Markov Chain Monte Carlo (MCMC) estimation techniques with the two-step inference functions for margins (IFM) method, we model dependence between lifetimes in spousal, parent–child and child–parent relationships, using copulas to capture the strength of association. Dependence is observed to be strongest in child–parent relationships and, in comparison to the high-income countries of data sets previously studied, of lesser significance in the husband and wife case, often referred to as broken-heart syndrome. Given the traditional use of UK mortality tables in the modelling of mortality in Egypt, the findings of this paper will help to inform appropriate mortality assumptions specific to the unique structure of the Egyptian scheme. Full article

The distribution and evolution of city size are critical for town layout optimization. Based on the most recent classification standards and census data for 2010 and 2020, this paper aims to explore China’s city size distribution above the prefecture level. Using the rank-size law, Kernel density estimation, Spatial Gini coefficient, and Markov transition matrix, the newest city size distribution characteristics and spatial evolution patterns in China are shown from national and regional viewpoints. Our main findings are as follows: (1) Over the period from 2010 to 2020, China’s city size distribution follows the rank-size law but deviates from Zipf’s ideal. The distribution of city size is centralized in general. (2) China’s city-size hierarchy exhibits a good “olive” structure, with fewer megacities but larger populations. The growth rate of small and medium-sized cities is higher than the number of medium-sized cities. (3) China’s cities have grown greatly in size, with more than a third of them expanding. Over the last decade, high-ranking cities have become the primary driver of change. (4) There are disparities in city size between regions. A diminishing trend can be seen in three key economic zones. Full article

Land-use changes have profound effects on both socio-economic development and the environment. As a result, to optimize land-use planning and management, models are often employed to identify land-use patterns and their associated driving forces. In this work, physical and socioeconomic factors within the Yangtze River Delta Urban Agglomeration (YRDUA) from 2000 to 2015 were identified, integrated, and used as the foundation for a CLUMondo model. Subsequently, the Markov model and the CLUMondo model were combined to predict land-use changes in 2035. Natural growth (NG), economic development (ED), ecological protection (EP), and coordinated social and economic development (CSE) scenarios were set according to the land-use date in the assessment. Results showed that: (1) From 2000 to 2015, urban land increased by 8139.5 km² (3.93%), and the paddy field decreased by 7315.8 km² (8.78%). The Kappa coefficient of the CLUMondo model was 0.86, indicating that this model can be used to predict the land-use changes of the YRDUA. (2) When this trend was used to simulate landscape patterns in 2035, the land-use structure and landscape patterns varied among the four simulated urban development scenarios. Specifically, urban land increased by 47.6% (NG), 39.6% (ED), 32.9% (EP), and 23.2% (CSE). The paddy field was still the primary landscape, with 35.85% NG, 36.95% ED, 37.01% EP, and 36.96% CSE. Furthermore, under all four scenarios, the landscape pattern tended to simplify and fragment, while connectivity and equilibrium diminished. The results provided herein are intended to elucidate the law of urban agglomeration development and aid in promoting urban sustainable development. Full article

Optimal control problems are applied to a variety of dynamical systems with a random law of motion. In this paper we show that the random degradation processes defined on a discrete set of intermediate degradation states are also suitable for formulating and solving optimization problems and finding an appropriate optimal control policy. Two degradation models are considered in this paper: with random time to an instantaneous failure and with random time to a preventive maintenance. In both cases, a threshold-based control policy with two thresholds levels defining the signal state, after which an instantaneous failure or preventive maintenance can occur after a random time, and a maximum number of intermediate degradation states is applied. The optimal control problem is mainly solved in a steady-state regime. The main loss functional is formulated as the average cost per unit of time for a given cost structure. The Markov degradation models are used for numerical calculations of the optimal threshold policy and reliability function of the studied degrading units. Full article

We study the structure of supply chain trust networks (SCTNs) by analyzing the evolution of the networks. An SCTN here comprises enterprises in a fully competitive market connected through the preferential attachment mechanism. A Markov chain analysis is used to understand how various factors affect the structure of the SCTNs. The evolution of the SCTNs is also analyzed to identify the asymmetric conditions required for the degree distribution of the SCTNs to obey the power law distribution. The simulation results show that, when the degree of willingness to initiate a trust relationship and the attractiveness index of the supply chain networks meet certain criteria, the underlying network is of a scale-free nature. Full article

Measure-valued Pólya urn processes (MVPP) are Markov chains with an additive structure that serve as an extension of the generalized k-color Pólya urn model towards a continuum of possible colors. We prove that, for any MVPP ${\left({\mu }_n\right)}_{n\ge 0}$ on a Polish space $\mathbb{X}$, the normalized sequence ${({\mu }_n/{\mu }_n\left(\mathbb{X}\right))}_{n\ge 0}$ agrees with the marginal predictive distributions of some random process ${\left(X_n\right)}_{n\ge 1}$. Moreover, ${\mu }_n={\mu }_{n-1}+R_{X_n}$, $n\ge 1$, where $x\mapsto R_x$ is a random transition kernel on $\mathbb{X}$; thus, if ${\mu }_{n-1}$ represents the contents of an urn, then $X_n$ denotes the color of the ball drawn with distribution ${\mu }_{n-1}/{\mu }_{n-1}\left(\mathbb{X}\right)$ and $R_{X_n}$—the subsequent reinforcement. In the case $R_{X_n}=W_n{\delta }_{X_n}$, for some non-negative random weights $W_1,W_2,\dots$, the process ${\left(X_n\right)}_{n\ge 1}$ is better understood as a randomly reinforced extension of Blackwell and MacQueen’s Pólya sequence. We study the asymptotic properties of the predictive distributions and the empirical frequencies of ${\left(X_n\right)}_{n\ge 1}$ under different assumptions on the weights. We also investigate a generalization of the above models via a randomization of the law of the reinforcement. Full article

Land-use change is an important contributor to atmospheric carbon emissions. Taking Jinhua city in eastern China as an example, this study analyzed the effects on carbon emissions by land-use changes from 2005 to 2018. Then, carbon emissions that will be produced in Jinhua in 2030 were predicted based on the land-use pattern predicted by the CA-Markov model. Finally, a low-carbon optimized land-use pattern more consistent with the law of urban development was proposed based on the prediction and planning model used in this study. The results show that (1) from 2005 to 2018, the area of land used for construction in Jinhua continued to increase, while woodland and cultivated land areas decreased. Carbon emissions from land use rose at a high rate. By 2018, carbon emissions had increased by 1.9 times compared to 2015. (2) During the 2010–2015 period, the total concentration of carbon emissions decreased due to decreases in both the rate of growth in construction land and the rate of decline in a woodland area, as well as an adjustment of the energy structure and the use of polluting fertilizer and pesticide treatments. (3) The carbon emissions produced with an optimal land-use pattern in 2030 are predicted to reduce by 19%. The acreage of woodland in Jinhua’s middle basin occupied by construction land and cultivated land is predicted to reduce. The additional construction land will be concentrated around the main axis of the Jinhua-Yiwu metropolitan area and will exhibit a characteristic ribbon-form with more distinct clusters. The optimized land-use pattern is more conducive to carbon reduction and more in line with the strategy of regional development in the study area. The results of this study can be used as technical support to optimize the land-use spatial pattern and reduce urban land’s contribution to carbon emissions. Full article

Humans currently face a problematic ecological dilemma regarding economic growth. It is difficult to meet human needs by only studying economic growth created by artificial costs, and all countries need to pay attention to the task of improving the level of human welfare under the constraints of an ecological environment from the perspective of sustainable development. The focus of ecological wellbeing performance (EWP) is how to achieve the maximum welfare level output or achieve higher welfare level improvement with the fewest conversions of natural and ecological inputs. In this paper, we use the super-efficiency SBM model to measure the EWP of Chinese provinces and cities, traditional and spatial Markov probability transfer matrices are established based on time series analysis and spatial correlation analysis of the global Moran’s index, and the characteristics of the spatiotemporal variations of EWP are analyzed by comparing the matrices. The evolution trend for a certain future period is predicted, and the influences of geographical spatial patterns on the spatiotemporal evolution of EWP are discussed. On this basis, according to the calculation and analysis of the characteristics of China’s EWP, provinces and cities in China need to focus on improving their own resource utilization efficiency and strengthen environmental supervision to improve EWP. Finally, policy recommendations are put forward. First, special laws and regulations need to be introduced for resource utilization and ecological protection. The second recommendation is to promote and improve the mechanism of public participation in the rational utilization of resources and protection of the ecological environment. The third recommendation is to establish a dynamic monitoring system for resource utilization and ecological environmental protection. The fourth recommendation is to strengthen structural adjustment and accomplish high-quality economic development. Full article