Re-Estimation of Agricultural Production Efficiency in China under the Dual Constraints of Climate Change and Resource Environment: Spatial Imbalance and Convergence

Climate change and farmland environmental pollution have put greater pressure on the sustainability of agricultural production. Based on the provincial panel data of mainland China from 1978 to 2018, climate variables such as precipitation, temperature, and sunshine hours are included into the input indicators, and agricultural non-point source pollution and carbon emissions are taken as undesirable outputs, the agricultural production efficiency (APE) under the dual constraints of climate change and the resource environment was estimated by the super slacks-based measure (SBM)-undesirable model. On the basis of the trajectory of the imbalanced spatiotemporal evolution of APE shown by Kernel density estimation and the standard deviational ellipse (SDE)–center of gravity (COG) transfer model, the spatial convergence model was used to test the convergence and differentiation characteristics of APE. Under the dual constraints, APE presents a “bimodal” distribution with a stable increase in fluctuation, but it is still at a generally low level and does not show polarization, among which the APE in the northeast region is the highest. The COG of APE tends to transfer towards the northeast, and the coverage of the SDE is shrinking, so the overall spatial pattern is characterized by a tendency of clustering towards the north in the north-south direction and a tendency of imbalance in the east-west direction. APE has significant spatial convergence, and there is a trend of “latecomer catching-up” in low-efficiency regions. The introduction of spatial correlation accelerates the convergence rate and shortens the convergence period. The convergence rate is the highest in the central and western regions, followed by that in the northeastern region, and the convergence rate is the lowest in the eastern region. In addition, the convergence rate in different time periods has a phase change. The process of improving the quality and efficiency of agricultural production requires enhancing the adaptability of climate change, balancing the carrying capacity of the resource environment, and strengthening inter-regional cooperation and linkage in the field of agriculture.

A graph-based computerized optimal conceptual design synthesis within the distributed multi-disciplinary resource environment

The trend of inter-disciplinary conceptual design synthesis requires designers to involve more and more distributed multi-disciplinary design resources. Therefore, this paper proposes a graph-based computerized optimal conceptual design synthesis to help designers explore novel design schemes within the distributed multi-disciplinary resource environment. The design resources tightly related to the design goal can be extracted from the huge resource environment by a proposed searching engine. The optimal design scheme can be generated from these related design resources by a proposed graph-based algorithm. A set of computer applications called Automatic Conceptual Design System (ACDS) is established to verify the feasibility of this proposed conceptual design synthesis, and a garbage power system’s conceptual design is completed by this software prototype.

Stability criteria for the consumption and exchange of essential resources

Models of pairwise interactions have informed our understanding of when ecological communities will have stable equilibria. However, these models do not explicitly include the effect of the resource environment, which has the potential to refine or modify our understanding of when a group of interacting species will coexist. Recent consumer-resource models incorporating the exchange of resources alongside competition exemplify this: such models can lead to either stable or unstable equilibria, depending on the resource supply. On the other hand, these recent models focus on a simplified version of microbial metabolism where the depletion of resources always leads to consumer growth. Here, we model an arbitrarily large system of consumers governed by Liebig's law, where species require and deplete multiple resources, but each consumer's growth rate is only limited by a single one of these multiple resources. Consumed resources that do not lead to growth are leaked back into the environment, thereby tying the mismatch between depletion and growth to cross-feeding. For this set of dynamics, we show that feasible equilibria can be either stable or unstable, once again depending on the resource environment. We identify special consumption and production networks which protect the community from instability when resources are scarce. Using simulations, we demonstrate that the qualitative stability patterns we derive analytically apply to a broader class of network structures and resource inflow profiles, including cases in which species coexist on only one externally supplied resource. Our stability criteria bear some resemblance to classic stability results for pairwise interactions, but also demonstrate how environmental context can shape coexistence patterns when ecological mechanism is modeled directly.

Hybrid Resource Environmental Value Chain Model Based on a Discrete Time Algorithm

Due to the inconsistency between resource environment and value data types, the hybrid model of resource environment value chain cannot effectively coordinate the relationship among resources, environment, and value chain. The circulation of resource chain, ecological chain, and value chain is not completed independently; they are intertwined and promote each other. Therefore, this paper proposes a hybrid resource environmental value chain model based on a discrete time algorithm. Analyze the hybrid internal structure of resource chain, environment chain, and value chain model; integrate the natural resource information through the objective function of natural resource integration; obtain the indicators affecting the environment; and complete the analysis of the characteristics of environmental change. On this basis, the relationship between resources, environment, and economic value is analyzed, and the hybrid content of resources, environment, and value chain is determined. The discrete-time algorithm is introduced to transform the hybrid content into the same data format, obtain the objective function and constraints of the resource environment value chain hybrid model, and complete the construction of the resource environment value chain hybrid model based on the discrete-time algorithm. The simulation results show that the hybrid model designed in this paper can effectively improve the resource saving rate, up to 97%, and the error of resource environment value chain data fusion is the lowest, and the time is less than 1 min which was a considerable achievement.