Characterization and Evolution of a Digital Economy Ecosystem Based on an Interspecies Competition Model

This paper provides an in-depth study and analysis of the characterization of the digital economy ecosystem and the mechanism of eye-flowering through the method of interspecies competition. The evolutionary game model of symbiotic decision-making in the entrepreneurial ecosystem is constructed, the evolutionary process of symbiotic decision-making of subjects is analyzed through mathematical derivation, and the symbiotic decision-making process of subjects is simulated through computer simulation to answer how the subjects of the entrepreneurial ecosystem make symbiotic decisions and explore the mechanism of symbiotic formation of the entrepreneurial ecosystem. Then, based on the ecological perspective, the symbiotic evolution model of entrepreneurial ecosystem subjects is constructed from the subject level, the equilibrium point of the evolution of entrepreneurial ecosystem subjects, the stability conditions, and the relationship between the equilibrium point and the symbiosis model are analyzed, and the symbiotic evolution paths of entrepreneurial ecosystem subjects under different symbiosis modes, initial population size, maximum size, and natural growth rate are presented with simulation experiments, respectively. The main characteristics and manifestations of the dynamic evolution of the platform ecosystem are analyzed, and the key competitive factors that determine the dynamic evolution of the platform ecosystem are depicted. Then, according to the inherent characteristic laws of the platform ecosystem, the complex network approach is applied to construct a dynamic evolution model with originality and wide applicability for the change of bilateral user scale. Based on the dynamic evolution process, the relationship between model parameters and business performance is explored, and the trajectory of bilateral user size change over time and the range of parameters are derived by numerical calculation. Finally, using Monte Carlo simulation methods, the dynamic evolution model is used to predict the future operating conditions of platform enterprises, providing a valuation basis for investors to make investment decisions and helping platform managers to formulate business strategies.

Evolutions of Oil Generation and Expulsion of Marine-Terrestrial Transitional Shales: Implications From a Pyrolysis Experiment on Water-Saturated Shale Plunger Samples

Shale reservoirs are characterized by self-generation and self-accumulation, and the oil generation and expulsion evolution model of organic-rich shales is one of important factors that obviously influence the enrichment and accumulation of shale oil and gas resources. At present, however, relevant studies on marine-terrestrial transitional shales are inadequate. In this study, a pyrolysis experiment was performed on water-saturated marine-terrestrial transitional shale plunger samples with type Ⅱb kerogen to simulate the evolutions of oil generation and expulsion. The results indicate that marine-terrestrial transitional shales have wider maturity ranges of oil generation and expulsion than marine and lacustrine shales, and the main stages of oil expulsion are later than those of oil generation, with corresponding Ro values of 0.85%–1.15% and 0.70%–0.95%, respectively. Although the oil generation and expulsion process induced a fractionation in compositions between the expelled and retained oils, both the expelled and retained oils of marine-terrestrial transitional shales are dominated by heavy compositions (resins and asphaltenes), which significantly differs from those of marine and lacustrine shales. The kerogen of marine-terrestrial transitional shales initially depolymerized to transitional asphaltenes, which further cracked into hydrocarbons, and the weak swelling effects of the kerogen promoted oil expulsions. The oil generation and expulsion evolutions of these shales are largely determined by their organic sources of terrigenous higher organisms. This study provides a preliminary theoretical basis to reveal the enrichment mechanism of marine-terrestrial transitional shale oil and gas resources.

A Continuous-Time Network Evolution Model Describing 2- and 3-Interactions

A continuous-time network evolution model is considered. The evolution of the network is based on 2- and 3-interactions. 2-interactions are described by edges, and 3-interactions are described by triangles. The evolution of the edges and triangles is governed by a multi-type continuous-time branching process. The limiting behaviour of the network is studied by mathematical methods. We prove that the number of triangles and edges have the same magnitude on the event of non-extinction, and it is eαt, where α is the Malthusian parameter. The probability of the extinction and the degree process of a fixed vertex are also studied. The results are illustrated by simulations.