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Mechanized and intelligent flower thinning is a high-speed flower thinning method nowadays. The classification and detection of flowers and flower buds are the basic requirements to ensure the normal operation of the flower thinning machine. Aiming at the problems of pear inflorescence detection and classification in the current intelligent production of pear orchards, a Y-shaped shed pear orchard inflorescence recognition algorithm Ghost-YOLOv5s-BiFPN based on improved YOLOv5s was proposed in this research. The detection model was obtained by labeling and expanding the pear tree bud and flower images collected in the field and sending them to the algorithm for training. The Ghost-YOLOv5s-BiFPN algorithm used the weighted bidirectional feature pyramid network to replace the original path aggregation network structure, and effectively fuse the features of different sizes. At the same time, ghost module was used to replace the traditional convolution, so as to reduce the amount of model parameters and improve the operation efficiency of the equipment without reducing the accuracy. The field experiment results showed that the detection accuracy of the Ghost-YOLOv5s-BiFPN algorithm for the bud and flower in the pear inflorescence were 93.21% and 89.43%, respectively, with an average accuracy of 91.32%, and the detection time of a single image was 29 ms. Compared with the original YOLOv5s algorithm, the detection accuracy was improved by 4.18%, and the detection time and model parameters were reduced by 9 ms and 46.63% respectively. Compared with the original YOLOV5s network, the mAP and recall rate were improved by 4.2% and 2.7%, respectively; the number of parameters, model size and floating point operations were reduced by 46.6%, 44.4% and 47.5% respectively, and the average detection time was shortened by 9 ms. With Ghost convolution and BIFPN adding model, the detection accuracy has been improved to a certain extent, and the model has been greatly lightweight, effectively improving the detect efficiency. From the thermodynamic diagram results, it can be seen that BIFPN structure effectively enhances the representation ability of features, making the model more effective in focusing on the corresponding features of the target. The results showed that the algorithm can meet the requirements of accurate identification and classification of pear buds and flowers, and provide technical support for the follow-up pear garden to achieve intelligent flower thinning.

【Background】 For reservoirs with non-flood season floods, small and medium-sized floods as important water resources or high water utilization rate, it is very meaningful to establish a reasonable step-size optimization model with variable time period and obtain a relatively high precision solution result. However, few answers have been given to this question over the years. 【Objective】 In order to study the integration and optimization of time step size and constraints in long series in non-flood season flood, medium and small flood regulation and power generation dispatching simulation, and to improve the comprehensive benefits of reservoir operation. 【Method】 A multi-strategy hybrid search algorithm for artificial bee colony in variable time period was established, and the optimal operation model of reservoir with the largest generating capacity under multiple constraints in a long series of variable time periods was constructed, based on the case application of Wan’an Reservoir. 【Result】 In non-flood season, the water utilization rate increased by 3%, which enhanced the utilization of flood resources; the artificial bee colony optimization algorithm with Multi Strategy hybrid search alleviated the contradiction between the selection of time step size and the calculation precision and convergence speed in the multi constraint optimization simulation calculation, and effectively improved the optimization efficiency and opening of standard artificial bee colony algorithm Ability. 【Conclusion】 The research results can provide ideas for improving the comprehensive benefits of non-flood season flood, medium and small flood regulation and power generation dispatching.

With the change of global climate and underlying surface characteristics, and increasing human activities, hydro-meteorological factors such as precipitation, evaporation, and runoff. Etc., are directly affected, therefore the assumption of stationarity may no longer exist. In a changing environment, the conventional runoff forecasting methods become invalid, which brings challenges to accurate hydrometeorological forecast. A hydrological model based on the changing environment was employed to forecast the runoff at Nanchang Section of Ganjiang River in this paper, and the rationality and validity of the built model were verified. The results shows that the built hydrological model has high accuracy in the short-term runoff forecasting, and better forecasting effect has been obtained after the parameters calibration and the real-time correction of the predicted runoffs, which can provide the strong support for the scientific water resources operation decision and also provide the boundary conditions of water level and water quality for the hydrodynamic and water-quality simulation at the Nanchang Section of the Ganjiang River.

Aiming to investigate the weather characteristics and mesoscale system in the heavy rainstorm process on Jul 26, 2017 of Yellow River, the conventional observations and mesoscale numerical model (WRF) and its assimilation system 3DVAR was utilized to simulate the major precipitation period. The difference between the results of model with assimilation observation date of meteorological observation stations and without assimilation were also discussed. the results indicates that upper at 500hPa and shear line at 850hPa form the forward-titling trough which provides favorable instability conditions for generation of rainstorm. stability of subtropical high is beneficial to the water flux transporting to main precipitation zone. the wind shear at 850hPa and surface cyclone are the mesoscale systems. By comparing the simulations with and without assimilation, the result showed that the simulation with assimilation improved obviously the location of heavy rain and spatial distribution of different levels of precipitation. Of which the region with precipitation below 10mm simulated by experiment with assimilation was greatly improved. At the factors of atmospheric circulation field, the intensities of water vapor transportation and surface cyclone have strengthened after assimilation, thus can support more favorable conditions for development of convection's system. its implied that simulations after assimilation improve the spatial structure of initial field, and have an essential effect on simulating mesoscale convective system's structure.

The traffic bridges along the route of South-to-North Water Diversion Project are numerous. Once a traffic accident occurs causing pollutants in the channel, the water safety, ecological environment and economic development of water receiving areas along the line will be affected . We investigate the bridges along the channel, focusing on the investigation and analysis of hazardous chemicals, nearby backwater gates and water inlets involving 173 cross-channel bridges with large traffic volume. The risk evaluation index system of sudden water pollution is established in this study, while the risk of different bridges is evaluated. We divide bridges in three risk grades, and delimit key prevention areas and key monitoring objects. And the stress of traffic risk factors on the water quality safety is summarized. It is significant for being regarded as basis for contingency plans, hierarchical responses and emergency material reserve for the middle line of the south-to-north water diversion project.

The total length of the main channel of the South-to-North Water Transfer Project is 1432 kilometers. There are nearly 1, 000 supporting mechanical and electrical equipment along the channel gate station. At the same time, there are more than 1, 000 main roads with channel crossing roads along the route. Oil spills may occur due to various reasons such as equipment leakage or traffic accidents. Entering the channel directly causes pollution of water quality. The pollution of water quality will directly endanger the health of human beings. Therefore, it is essential to quickly and efficiently remove oil pollutants from the water supply channels. This paper analyzes the basic characteristics of the Middle Route Project of South-to-North Water Transfer, and the risk sources of sudden oil pollution, and the common degreasing devices such as oil booms, oil absorbing pads, and oil removal devices based on steel structure pontoons in the main trunk The applicability was analyzed. The results show that the traditional oil-absorbing felt, oil boom and other degreasing devices have poor applicability in the middle line, which can not meet the requirements of the mid-line water quality and channel flow rate, and the adaptability to the channel engineering characteristics is also insufficient. The degreasing device based on the steel structure pontoon can adapt to the current situation of the midline, and has good effects in preventing the oil film from escaping and splashing. Therefore, in general, the degreasing device based on the steel structure pontoon is suitable for the midline burst oil. Effective measures and means of pollution accidents

This paper focuses on the analysis of the flow field of Danjiangkou Reservoir under the action of wind stress. Based on the analysis of the annual wind field data of Danjiangkou Reservoir, the three-dimensional hydrodynamic model of Danjiangkou Reservoir was established. The distribution of water flow field in the reservoir area under five different wind directions and two different wind speeds was studied. The simulation results were compared with the flow field without wind. The results show that when the wind speed in the reservoir area is 3.3m/s, the surface velocity and flow direction change less under the same wind conditions as the potential flow direction. Under the wind condition opposite to the potential flow direction, the reservoir area is locally generated. The small circulation and surface flow are more disordered; when the wind speed reaches 10.0m/s, under the same wind condition as the potential flow direction, the surface velocity of the reservoir area increases significantly. Under the wind condition opposite to the direction of the potential flow, a stable counterclockwise circulation is generated, and the wind direction dominates the surface layer. seriously affecting the flow field distribution in the reservoir area. The research results in this paper can provide support for the reservoir in the formulation of emergency water pollution emergency strategy and the formulation of real-time scheduling plan.

To highlight the differences in water quality impacts of different indicators in water samples, this paper proposes a grey clustering method based on improved analytic hierarchy process to evaluate the quality of surface water. According to the pollution degree of different indicators in the water quality sample, the importance score is assigned, and the weight of different indicators is calculated by the analytic hierarchy process. The weight participates in the calculation of the grey clustering coefficient, and the evaluated water quality category considers the difference of the contribution rate of different pollutant indicators. The water quality samples of three water periods (Abundant, Normal, and Poor water flow periods) in the four sections of Qingshui River in Duyun City (Tea garden, Youhang, Yingpan and Jiadeng) were selected for evaluation, and the conventional grey clustering method and single factor method were used. The evaluation results were compared and analyzed. The evaluation results show that the improved grey clustering method is more scientific and reasonable and can provide a basis for water quality assessment and water environment management of water environment management departments.

Along with social economy development, the total water consumption increased year by year. The conflicts between water supply and water consumption is growing. Water resources optimization dispatch, which is used to allocate water resources to meet the demand of water user on both time scale and spatial scale, plays an important role in water resources management. Aiming at improving the spatial allocation ability of traditional optimization algorithms, a uniform spatial allocation strategy is proposed accordingly. The proposed method is used to improve the performance of optimization algorithm to obtain solutions which can uniform the water supply in spatial scale. Simulation results show that the maximum ratio of water deficiency gained by the proposed method is smaller than that obtained by the original algorithm. The proposed method is effective to balance the demand of water users in spatial scale. Copyright © 2018 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 10th International Conference on Applied Energy (ICAE2018).

Currently, more and more arid and semi-arid areas in Northwestern China are facing with severe water problems. The Shiyanghe River basin is in the east of Hexi Corridor in Gansu Province with little rainfall and fragile ecological environment. As water pollution and water waste exist with water shortage, a serious conflict of water supply and demand is arising, accompanied with a series of water ecological problem. Thus, we must take measures to ensure the water resources to be used properly for long-term sustainable development. Water resources operation is taken reasonably which can achieve the overall regulation of basin water resources and which is an important method to achieve sustainable development. Taking the Shiyanghe River Basin as the research object, based on the basin data, this paper built the runoff forecasting model, water demand prediction model, water resources operation model and groundwater simulation model. Therefore, an information system platform for water resources operation in Shiyanghe River Basin is built based on GIS with an integrated data and computational models.

For the sudden upstream water interruption in the canal of an emergency, the existing research method guiding gate control is mainly feed-forward compensation algorithm, under which algorithm the interruption of water diversions is the upstream first and then the downstream. In order to achieve a more flexible water demand for different water diversions purpose, this study used PI water level difference feedback control algorithm to control the gate under this condition. The research results showed that the PI water level difference feedback control algorithm can make the change trend of water level of multi-pool close and reduce the rate of water level decline, and thus prolong the continuous delivery time of pools with offtake delivery demand under sudden upstream water interruption. Moreover, the PI water level difference method has good robustness and can be applied to more complex combinations of inflow and delivery changes. This study provides another way of thinking for the regulation of the gate in the case of sudden upstream water interruption.

Taking the typical main canal of the Middle Route of South-to-North Water Transfer project as an example, the numerical simulation study on the variation law of water level before sluice under different wind conditions is carried out. First, based on numerical simulation, mathematical induction, and statistical analysis method, the influences of wind speed, wind duration and wind direction on water level fluctuation are put forward and the fast prediction formula of maximum water level fluctuation under wind influence is extracted. Then, the feasibility of the fast prediction formula is verified by the actual monitoring data. The results show that: (1) the duration of wind has little influence on the maximum water level variation, and the maximum error is 9.83 %; (2) the maximum water level amplitude increases with increasing wind speed and decreases with increasing wind source distance; (3) the whole water level variation is symmetrical about the angle α=180°, and 0° to 90° is a period of maximum water level variation; (4) the error between the calculation result of the fast prediction formula and the measured result is 1.25 %, which shows that the maximum water level prediction formula is relatively applicable to open channel water transfer project. These research results provide a scientific basis for routine dispatching of water conveyance projects.