No abstract

Yield estimation using remote sensing data is a research priority in modern agriculture. The rapid and accurate estimation of winter wheat yields over large areas is an important prerequisite for food security policy formulation and implementation. In most county-level yield estimation processes, multiple input data are used for yield prediction as much as possible, however, in some regions, data are more difficult to obtain, so we used the single-leaf area index (LAI) as input data for the model for yield prediction. In this study, the effects of different time steps as well as the LAI time series on the estimation results were analyzed for the properties of long short-term memory (LSTM), and multiple machine learning methods were compared with yield estimation models constructed by the LSTM networks. The results show that the accuracy of the yield estimation results using LSTM did not show an increasing trend with the increasing step size and data volume, while the yield estimation results of the LSTM were generally better than those of conventional machine learning methods, with the best R2 and RMSE results of 0.87 and 522.3 kg/ha, respectively, in the comparison between predicted and actual yields. Although the use of LAI as a single input factor may cause yield uncertainty in some extreme years, it is a reliable and promising method for improving the yield estimation, which has important implications for crop yield forecasting, agricultural disaster monitoring, food trade policy, and food security early warning.

In this paper we give a closed formula for the graded dimension of the cyclotomic quiver Hecke algebra R Λ (β) associated to an arbitrary symmetrizable Cartan matrix A = (a ij ) i,j ∈ I, where Λ ∈ P + and β ∈ Q + n . As applications, we obtain some necessary and sufficient conditions for the KLR idempotent e(ν) (for any ν ∈ I β ) to be nonzero in the cyclotomic quiver Hecke algebra R Λ (β). We decompose dim R Λ (β) into a sum of some products of dim R Λ i (β i ) with Λ = i Λ i and β = i β i . We construct some explicit monomial bases for the subspaces e( ν)R Λ (β)e(µ) and e( ν)R Λ (β)e(µ) of R Λ (β), where µ ∈ I β is arbitrary and ν ∈ I β is a certain specific n-tuple (see Section 4). Finally, we show that R Λ (β) is indecomposable if β = n i=1 α i with {α i |1 ≤ i ≤ n} being distinct.

No abstract

No abstract