Enhancing septoria leaf blotch forecasts in winter wheat II: model architecture and validation results

In precision agriculture, pesticides and other inputs shall be used precisely when (and where) they are needed. European Directive 2009/128/EC calls for respecting the principles of integrated pest management (IPM) in the member states. To clarify the question, when, for instance, fungicide use is needed, the well-established economic principle of IPM may be used. This principle says that pests shall be controlled when the costs of control correspond with the damage the pests will cause. Disease levels corresponding with the costs of control are referred to as control thresholds in IPM. Several models have been developed in plant pathology to predict when epidemics will occur, but hardly any of these models predicts a control threshold directly limiting their usefulness for answering the question when pest control is needed according to the principles of IPM. Previously, we quantified the temporal distance between critical rainfall periods and the breaking of the control threshold of Zymoseptoria tritici on winter wheat as being affected by temperature, based on data from 52 field experiments carried out in Luxembourg from 2005 to 2016. This knowledge was used to construct the ShIFT (SeptorIa ForecasT, https://shift.list.lu/) model, which has been validated using external data recorded between 2017 and 2019. Within the efficacy period of a systemic fungicide, the model allowed correct predictions in 84.6% of the cases, while 15.4% of the cases were predicted falsely. The average deviation between the observed and predicted dates of epidemic outbreaks was 0.62 ± 2.4 days with a maximum deviation of 19 days. The observed and predicted dates were closely correlated (r = 0.92, P < 0.0001). Apart from outliers, the forecast model tested here was reliable within the period of efficacy of current commercial fungicides.

Research and Simulation of Handover Algorithm in Mobile Communication System

In order to improve the handover rate and quickly handover the target cell, the handover control algorithm of the mobile communication system is explored, and the handover algorithm that combines signal strength and signal quality is researched. At the same time, it is experimentally demonstrated, and the handover user and the new user will be connected. The influence of the entry control threshold setting on the system was compared.

Simulation of multi-power composite electric tractor based on power fluctuation ratio

All Combined with the characteristics of frequent abrupt load in the field operation of tractors, and aiming at the problems of single motor energy input and large fluctuation of battery state in the energy system of pure electric tractors, a power supply structure with multiple battery packs was proposed. A dynamic model considering real-time power and load fluctuation and a multi-power cooperative input model based on fuzzy control threshold logic rule based on power fluctuation ratio are established. Matlab and Simulink are used to simulate the model and compare it with the traditional single power model. The results show that when the speed is constant ploughing, the output power of the lithium battery of the multi-power cooperative input model is effectively compensated compared with that of the single-power model under sudden load. The average fluctuation ratio of rising power decreases from 5.8% / s to 2.7% / s, which realizes “peak clipping” and “slow peak” when the current fluctuates greatly. and then made the estimation of battery state of charge (SOC) more accurate, and prolonged the battery life.

An Advanced Anti-Slip Control Algorithm for Locomotives Under Complex Friction Conditions

The locomotive wheelsets configured with high-power AC traction motors are very prone to slip under poor friction conditions, which usually impair traction/braking efficiency. To avoid the adverse consequence caused by the conspicuous slipping behaviors of wheels, the anti-slip control modules are consequently equipped on high-power locomotives. This paper presents an advanced anti-slip control algorithm for heavy-haul locomotives travelling with complex wheel/rail friction conditions. The proposed anti-slip control model is implemented in a three-dimensional (3D) heavy-haul train-track coupled dynamics model, in which the real-time estimation of wheel/rail adhesion conditions and relevant optimization adjustment of control threshold values are considered. The wheel/rail dynamic interactions of the heavy-haul locomotive under traction/braking conditions and multifarious friction conditions are investigated. The control effects of the anti-slip controllers with changeable and constant threshold values are compared. It is shown that the traction/braking loads and friction conditions have a significant effect on wheel/rail interactions. The optimal traction/braking efficiency can be realized by adopting the anti-slip controller with alterable threshold values.

The Analysis of Opinion Evolution and Control Based on the Prisoner’s Dilemma Game in Social Networks

In a social network, a user is greatly influenced by their neighbors’ opinions, and the user’s opinion updating can be regarded as the prisoner’s dilemma game. In view of such considerations, this paper proposes an opinion evolution and control model based on the prisoner’s dilemma game and gives the corresponding opinion evolution and control algorithm. Under different initial positive opinion proportions, different opinion control levels, and the same control threshold value and under different initial positive opinion proportions, different opinion control levels, and different opinion control threshold values in a scale-free network, the experiments illustrate the opinion evolution trends and control strategies according to the measures of changing the opinion control levels and opinion control threshold values for network regulators. The experiments show that the lower the initial positive opinion proportion is and the smaller (resp., larger) the control opinion threshold value chosen by the network regulators is, the lower (resp., higher) the opinion control level is; the larger the initial positive opinion proportion is and the larger the control opinion threshold value chosen by the network regulators is, the lower the opinion control level is.

Development of a wheat aphid population dynamics model based on cusp catastrophe theory

Aphids are a major global wheat pest that can cause considerable loss of yield. Modeling of aphid population dynamics is an integral part of management strategies to manage or control aphid populations. In this paper, first, a wheat aphid population dynamics model was developed based on a logistic model and the Holling III functional response, which includes three factors: temperature, natural enemies and insecticide. Second, this model fitted with a cusp catastrophe model to describe how abrupt changes in the wheat aphid population were influenced by these factors. Finally, the system was validated with field data from 2016 to 2018. The bifurcation set of the cusp catastrophe model was deemed to be the quantified dynamic control threshold, so an outbreak of aphid’s population can be explained according to the variation of control variables. In short, this aphid population model was successfully validated on survey data, which can be used to guide the prevention and control of aphids.

Loading Capacity of Sewage Sludge for Forestry Application in Chinese Provincial Capital Cities

The application of sewage sludge (SS) in forestry is considered a viable option. However, the long-term application of SS potentially leads to metal accumulation, posing an environmental risk. Understanding the loading capacity of SS for forestry application is therefore of great significance. We used data from published studies and statistical bulletins across 31 provincial capital cities (PCCs) in China to calculate the loading capacity (LC) of SS for forestry application for each PCC. The results are as follows: (1) the mean value of the priority control threshold was 33 t·ha−1·y−1 in 31 PCCs, while the variations ranged from 7 to 91 t·ha−1·y−1 among different PCCs. The priority control thresholds (Smins) of 1/2 PCCs were higher than 30 t·ha−1·y−1 (CJ-T 362-2011). The Smin values of Lanzhou, Tianjin, Hohhot, Shanghai, and Yinchuan were above 55 t·ha−1·y−1, but Smin values of Kunming and Changsha were below 10 t·ha−1·y−1. (2) Cd was the priority control metal in most of the PCCs (27/31), with the exception of Shanghai and Guangzhou (Cu), Beijing (Hg), and Tianjin (Zn). (3) The total loading capacity was 507 million t·y−1, which was 125 times higher than the total quantity of the dry SS (404 × 104 t) for the 31 PCCs. Our results have important practical significance for the use of urban sludge forest land in China and suggest that SS disposal policies need to be tailored to specific regions. We provide a scientific basis to guide the development of national and provincial forestry policies.