Most probable transition paths in eutrophicated lake ecosystem under Gaussian white noise and periodic force

The effects of stochastic perturbations and periodic excitations on the eutrophicated lake ecosystem are explored.Unlike the existing work in detecting early warning signals,this paper presents the most probable transition paths to characterize the regime shifts.The most probable transition paths are obtained by minimizing the Freidlin-Wentzell(FW)action functional and Onsager-Machlup(OM)action functional,respectively.The most probable path shows the movement trend of the lake eutrophication system under noise excitation,and describes the global transition behavior of the system.Under the excitation of Gaussian noise,the results show that the stability of the eutrophic state and the oligotrophic state has different results from two perspectives of potential well and the most probable transition paths.Under the excitation of Gaussian white noise and periodic force,we find that the transition occurs near the nearest distance between the stable periodic solution and the unstable periodic solution.

New Rural Community Construction or Retention Development:A Comparative Analysis of Rural Settlement Transition Mechanism in Plain Agriculture Area of China Based on Actor Network Theory

It is an important way to realize rural revitalization and sustainable development to guide rural settlement transition(RST)in an appropriate way.This paper uses actor network theory(ANT)to construct a theoretical framework for the study of RST.Taking two typical villages with different transition paths in rural areas of North China Plain as examples,this paper reveals the mechanism of RST and makes a comparative analysis.The results show that:1)after identifying problems and obligatory passage point,key actors recruit heterogeneous actors into the actor network by entrusting them with common interests,and realize RST under the system operation.2)Rural settlements under different transition paths have similarities in the problems to be solved,collective actions and policy factors,but there are differences in the transition process,mechanism and effect.The actor network and mechanism of RST through the path of new rural community construction are more complex and the transition effect is more thorough.In contrast,the degree of RST of retention development path is limited if there is no resource and location advantage.3)Based on the applicable conditions of different paths,this paper designs a logical framework of‘Situation-Structure-Behavior-Result’to scientifically guide the identification of RST paths under the background of rural revitalization.

An Improved Adaptive Minimum Action Method for the Calculation of Transition Path in Non-Gradient Systems

The minimum action method(MAM)is to calculate the most probable transition path in randomly perturbed stochastic dynamics,based on the idea of action minimization in the path space.The accuracy of the numerical path between different metastable states usually suffers from the“clustering problem”near fixed points.The adaptive minimum action method(aMAM)solves this problem by relocating image points equally along arc-length with the help of moving mesh strategy.However,when the time interval is large,the images on the path may still be locally trapped around the transition state in a tangle,due to the singularity of the relationship between arc-length and time at the transition state.Additionally,in most non-gradient dynamics,the tangent direction of the path is not continuous at the transition state so that a geometric corner forms,which brings extra challenges for the aMAM.In this note,we improve the aMAM by proposing a better monitor function that does not contain the numerical approximation of derivatives,and taking use of a generalized scheme of the Euler-Lagrange equation to solve the minimization problem,so that both the path-tangling problem and the non-smoothness in parametrizing the curve do not exist.To further improve the accuracy,we apply the Weighted Essentially nonoscillatory(WENO)method for the interpolation to achieve better performance.Numerical examples are presented to demonstrate the advantages of our new method.

Path Planning for Mobile Anchor Node in Localization Based on Ad-Hoc Localization Algorithm

For mobile anchor node static path planning cannot accord the actual distribution of node for dynamic adjustment. We take advantage of the high localization accuracy and low computational complexity of ad-hoc localization system( AHLos)algorithm. This article introduces mobile anchor nodes instead of the traditional fixed anchor nodes to improve the algorithm. The result shows that, through introduce the mobile anchor node, the information of initial anchor nodes can be configured more flexible.Meanwhile,with the use of the approximate location and the transition path,the distance and energy consumption of the mobile anchor node is greatly reduced.

Quantitative evaluation framework and application for regional water sustainability under local energy transition

Quantitatively analysing the impacts on regional water sustainability under the energy transition is vital to regional water management and specific technology selection,which is also relevant to dealing with climate change.This study proposed a new multi-indicator evaluation framework for regional water sustainability under local energy transition to quantitatively evaluate the water withdrawal and water environment during the energy transition from a lifecycle perspective.An integrated regional energy-water evaluation model was also developed based on the Low Emissions Analysis Platform with a combination of lifecycle assessment and water footprint analysis.Shaanxi province in China was then taken as a case study,and the impacts of its energy transition on regional water environmental sustainability,including quantity and quality,were investigated under five scenarios.Results showed that the large-scale application of carbon capture,utilisation and storage technology and bio-energy equipped with carbon capture and storage technology could have additional advantages regarding CO_(2) emissions.However,such technologies exhibit a minimal effect on improving water environmental quality and reducing water demand for the first time due to the leakage of absorbents,CO_(2) and other risky substances during capture,transportation and storage from a lifecycle perspective.This finding drives the innovation of related breakthrough technologies with the promotion of water and end-treatment technologies in the future.

Energy transition management towards a low-carbon world

1Introduction The challenge of climate change has led to the worldwide growing trends in developing a low-carbon,clean,and high-efficiency energy system,which is a significant pathway_to safeguard energy security and achieve sustainable development goals(Zhou et al.,2022).To respond to calls for the energy system's transformation,governments have ambitiously implemented various incentive policies by considering the specific circumstances in human energy services and activities(Ding et al.,2020).Despite the world having made notable progress in low-carbon energy transition,it faces numerous challenges,such as the surging energy demand,lack of renewable technology,and imperfect transition management system(Strunz,2018;Davidson,2019).

Dynamic Transition of Exchange Rate Regime in China

Thepaper considers the optimal transition path for China＇s exchange rate regime. How can China successfully make the shift from the current dollar peg regime to a more desirable regime, whether a basket peg or a floating regime？ To answer this question, we develop a dynamic small open economy general equilibrium model. We construct four transition policies based on a basket peg or a floating regime and compare the welfare gains of these policies relative to maintaining the dollar peg regime. Two main results are derived from the quantitative analysis using Chinese data from 1999Q1 to 2010Q4. First, following a gradual adjustment to a basket peg regime is the most appropriate path for China to take, with minimal welfare losses associated with the shift in the exchange rate regime. Second, a sudden shift to the basket peg is the second best solution, and is superior to a sudden shift to floating because the monetary authority can efficiently determine optimal weights to attach to currencies in the basket to achieve policy goals once they adopt a basket peg regime.

Stability, Accuracy and Cost of NEB and String Methods

In this paper,the zero-temperature string method and the nudged elastic band method for computing the transition paths and transition rates between metastable states are investigated.The stability,accuracy as well as computational cost of the two methods are discussed.The results are verified by numerical experiments.