Search

• The matrix representation of grey possibility function is provided. • The solution method of possibility function's turning points is given. • The "maximum criterion" decision paradox is solved. • A variable stage self-correcting grey clustering model is proposed. • The meteorological drought grade of 17 stations in china henan province is evaluated. The grey clustering model based on the possibility function is frequently used in system evaluation, but the setting of the possibility function is frequently subjective, which results in the weak credibility of the clustering results. In addition, the "maximum criterion" decision paradox of the model has fuzzy boundaries, making the clustering process impossible to program. Based on this, the possibility function is represented as a matrix in the paper, and the possibility function is calculated by an optimization model to guarantee the objectivity of the clustering results. A variable stage self-correcting grey clustering model is built by using the kernel weight transformation as the primary tool, "entropy subtraction" as the signal of the decision paradox, and "entropy non-subtraction" as the model's termination signal. The model's Matlab source code is provided to reduce the complexity of the model. The illustration and comparative analysis demonstrate the model's logic and efficacy. Using the model for the evaluation of the meteorological drought grade in Henan Province can offer a fresh perspective for meteorological departments to make choices and assessments. [ABSTRACT FROM AUTHOR]

Time series characterized by periodic fluctuations are widespread in reality behavioural systems, and accurate forecasting of them has important practical application value. In this paper, based on the idea of discrete grey model, dual interaction effects and the nonlinear characteristics of the system are considered under the perspective of dual processing, and the fluctuating trend of the periodic sequence is portrayed through the introduction of the periodic dummy variable, and at the same time, combined with the extended periodic rolling time window method, the rolling discrete grey periodic power model with the interaction effect under dual processing is proposed, namely DIE-RDGM(1,1, T) α model. Differential evolution algorithm (DE) are employed to determine the optimum power index. Finally, the new model was compared with nine other forecasting models by three instances and applied to the problem of agricultural drought forecasting in Zhoukou City and Anyang City, Henan Province. The results show: (1) The new model has demonstrated strong competitiveness, confirming its rationality, validity, and superiority. (2) The DE is suitable for power index optimization search. (3) The new model can better describe the periodic change rule of seasonal-scale soil moisture in the two cities, and the forecast results are consistent with the actual drought conditions. [ABSTRACT FROM AUTHOR]

Elucidating the evolution of cooperation is one of the greatest challenges in both evolutionary biology and social science. However, vast majority of existing studies simply assume that the interaction neighborhood and replacement neighborhood are symmetric, irrespective of the size of both neighborhoods. In this paper, we consider the asymmetrical setup, namely, the separation of interaction neighborhood and replacement neighborhood, into the prisoner’s dilemma game. In detail, it is assumed that there exist two types of players: player A possessing Moore interaction neighborhood and von Neumann replacement neighborhood and player B having von Neumann interaction neighborhood and Moore replacement neighborhood. Importantly, the fraction of former player is τ (the latter is 1 − τ ), and this ration keeps constant during the whole process. By means of Monte Carlo simulations, it is unveiled that cooperation can be promoted to the highest level at middle τ , which is related to the formation of giant cluster. Moreover, we also inspect the impact of uncertainty on the phase diagrams and find that middle τ completely changes the evolution trend of low or middle value. It is thus suggested the separation of interaction and replacement neighborhoods may shed new light into the solution of social dilemmas. [ABSTRACT FROM AUTHOR]

Abstract: Based on the grey system theory and methods, the grey-target decision-making problem is discussed, in which the attribute values are grey numbers and the maximum probability of the value of grey number is known. Firstly, the optimal effect vector is the positive bull’s-eye and positive bull’s-eye distance of each scheme is defined. Subjectively or objectively weighting method is integrated to determine the index weight and integrated optimization model of index weight is established. Finally, the critical effect vector is the negative bull’s-eye and negative bull’s-eye distance of each scheme is defined, then relative bull’s-eye distance and comprehensive the bull’s-eye distance of grey target decision-making are given. An example is also presented to illustrate the usefulness and effectiveness of the methods obtained in this paper and provides a new idea for grey target decision-making method research. [Copyright &y& Elsevier]

Abstract: Based on grey system theory, the decision-making problem is discussed, in which the attribute values are interval grey numbers and maximum probability of the value of grey number is known. Firstly, three-parameter interval grey number is defined, and the method of three-parameters grey interval incidence degree is presented by using the characteristic of this kind of grey number and the advantage of classical grey incidence decision making. Secondly, considering the proximity and comparability of space position and geometry shape among every scheme''s effect-evaluation vector, ideal project, and critical project, we construct the three-parameter grey interval slope incidence coefficient formula. Integrated with the above, the three-parameter grey interval incidence coefficient formula, the method of the grey interval synthesis close degree is given. Finally, by using the analytical technique of the expectation value of three-parameter interval grey numbers and projecting pursuit algorithm, the projection attribute function method is introduced. In addition, the corresponding algorithms of the above three methods are given. An example is used to demonstrate the rationality and validity of the proposed decision-making algorithms. A new approach is provided for the grey decision-making theory and its application. [Copyright &y& Elsevier]

Highlights: [•] A novel polyacetylene (1) was isolated from Artemisia lactiflora. [•] The structure was elucidated using extensive spectroscopic analysis. [•] The polyacetylene bears a novel C14-diacetylene skeleton. [•] Compound 1 showed HCT-8, BGC-823, A549 cytotoxicities against tumor cell lines. [Copyright &y& Elsevier]

Frequent drought is a critical limiting factor for regional agriculture development. Accurately evaluating regional agricultural drought risk contributes to raising disaster risk management and reducing drought disaster losses. This paper proposes a grey cloud clustering model based on panel data to assess the agricultural drought disaster risk of Henan province. The new model includes two parts. One component is indicator and time weights determination which uses the grey incidence analysis methods, the maximum deviation and maximum entropy principle, respectively. The other part is the construction of grey cloud possibility function which calculates the drought disaster risk grade. Then, the proposed model is applied for assessing the agricultural drought disaster risk of Henan Province at the regional scale, and the time scale selected is from 2012 to 2016. The agricultural drought disaster presents different spatial distribution in drought hazard, exposure, damage sensitivity and drought resistance capacity. The comprehensive risk evaluation results indicate that the drought risk in the most northern and southern regions of Henan Province is lower, while the western, mid-western and eastern regions have a higher risk. Compared with the traditional assessment models for disaster risk, the proposed model can recognize the random, fuzzy and grey uncertainties of the agricultural drought disaster system. Thus, it is a beneficial tool for drought disaster risk assessment and can help to make some suggestions for drought disaster mitigation. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we study the quasi-neutral limit of compressible Euler–Poisson equations in plasma physics in the torus . For well prepared initial data the convergence of solutions of compressible Euler–Poisson equations to the solutions of incompressible Euler equations is justified rigorously by an elaborate energy methods based on studies on an λ-weighted Lyapunov-type functional. One main ingredient of establishing uniformly a priori estimates with respect to λ is to use the curl–div decomposition of the gradient. [Copyright &y& Elsevier]

Abstract: In this paper, we investigate the convergence of the time-dependent and non-isentropic Euler–Maxwell equations to incompressible Euler equations in a torus via the combined quasi-neutral and non-relativistic limit. For well prepared initial data, the convergences of solutions of the former to the solutions of the latter are justified rigorously by an analysis of asymptotic expansions and energy method. [Copyright &y& Elsevier]