农业病虫害远程呼叫与咨询系统的设计与分析

农业病虫害远程呼叫与咨询系统是基于计算机协同工作思想,将专家系统、呼叫中心、网络多媒体及人工智能等多种技术结合设计的专家—坐席—用户交互平台,为农户进农业行病虫害方面的诊断、指导和咨询,解决我国农业生产分散、专家缺乏、科技服务与推广水平差等一系列现实问题。介绍了农业病虫害远程呼叫与咨询系统的总体开发流程以及平台体系结构,分析了该平台的建设步骤和关键技术以及系统平台推广的前景。     

核动力装置连续提棒事故的瞬态特性模拟

建立了描述反应堆与主冷却剂系统的物理、热工水力特性的数学模型。该模型应用埃米尔特插值法求解点堆动力学方程,其它方程采用半隐式差分法求解。在此基础上编制了模拟程序,并模拟了连续提棒事故的核动力装置瞬态呼应特性,经与理论分析的比较表明,本模拟符合实际情况,其数值处理方法正确,可为事故的处置提供依据,对反应堆的安全运行具有一定的参考价值。     

关于CPR1000核电机组低功率运行停运一台CRF泵的影响分析

文章对北方某核电站机组电功率850MW运行时停运一台CRF泵进行了分析,得出在保证设备可靠的情况下,停运一台CRF泵,机组可以正常运行,增加机组经济效益约6MWh;并对机组满功率时若单列凝汽器海水泄漏,一台CRF泵运行时,机组电功率的运行平台提供了借鉴。     

Tuning of linear ADRC with known plant information

Linear active disturbance rejection control (ADRC) is known for its simplicity and its performance in disturbance attenuation. Currently, tuning of linear ADRC (LADRC) is via the bandwidth idea. In this paper, tuning of LADRC with known plant information is investigated. It is shown that there are limitations using only two bandwidths to tune the LADRC controllers. To take advantage of the known plant information, a generalized ADRC (GADRC) method is proposed. Then the intrinsic link between the conventional LADRC and GADRC is analyzed. It is shown that the available plant model information used in GADRC can be utilized in the designs of the observer gain and the controller gain of the conventional LADRC. Simulation results demonstrate that with known plant information incorporated, the performance of a conventional LADRC can indeed be improved, especially for unstable, time-delayed and non-minimum phase processes.     

A SVR-based ensemble approach for drifting data streams with recurring patterns

Pattern drift is a common issue for machine learning in real applications, as the distribution generating the data may change under nonstationary environmental/operational conditions. In our previous work, a strategy based on Feature Vector Selection (FVS) has been proposed for enabling a Support Vector Regression (SVR) model to adaptively update with streaming data, but the proposed strategy suffers from the incapability of treating recurring patterns. An instance-based online learning approach is proposed in this paper, which can adaptively update an SVR-based ensemble model with steaming data points. The proposed approach reduces the computational complexity of the updating process by selecting only part of the newly available data and allows following timely the ongoing patterns by resorting to FVS. The proposed approach creates new sub-models directly from a basic model and the sub-models represent separately the data stream at different periods. A dynamic ensemble selection strategy is integrated in the approach to select the sub-models most relevant to the new data point for deriving the prediction, while reducing the influence of the irrelevant ones. The weights of the different models in the ensemble are updated, based on their prediction errors. Comparison results with several benchmark approaches on several synthetic datasets and on the dataset concerning the leakage from the first seal in a Reactor Coolant Pump, prove the efficiency and accuracy of the proposed online learning ensemble approach.     

植物叶面物理信息检测技术研究进展

针对节能减排技术中的节水灌溉及林业碳汇量计量等问题,需对植物的生长状态进行精确的无损检测.目前的方法是依据植物生理参数与其物理参数间的关系,将不可直接测得的生理参数量转化为可直接测得的物理参数量,利用植物叶面物理信息检测技术采集植物生理信息;通过植物叶面物理信息检测技术的研究,实现了对植物叶片各物理参数(如叶片厚度、叶表温度、叶片叶绿素含量及叶表气孔等)的实时测量,建立了叶面物理参数与植物生理状态的相关数学模型.这些工作对研究环境的响应机制、植物微观生长量及植物宏观特征的精确表征具有参考价值.     

Accuracy,robustness and behavior of the STICS soil–crop model for plant,water and nitrogen outputs: Evaluation over a wide range of agro-environmental conditions in France

Soil–crop models are increasingly used as predictive tools to assess yield and environmental impacts of agriculture in a growing diversity of contexts. They are however seldom evaluated at a given time over a wide domain of use. We tested here the performances of the STICS model (v8.2.2) with its standard set of parameters over a dataset covering 15 crops and a wide range of agropedoclimatic conditions in France. Model results showed a good overall accuracy, with little bias. Relative RMSE was larger for soil nitrate (49%) than for plant biomass (35%) and nitrogen (33%) and smallest for soil water (10%). Trends induced by contrasted environmental conditions and management practices were well reproduced. Finally, limited dependency of model errors on crops or environments indicated a satisfactory robustness. Such performances make STICS a valuable tool for studying the effects of changes in agro-ecosystems over the domain explored.     

Size matters? – The diverging influence of cutting length on growth and allometry of two Salicaceae clones

Short rotation coppices (SRC) are often established by inserting cuttings vertically into the soil. Longer cuttings are generally regarded as superior to establish plants on stress-prone sites. However, knowledge about above- and belowground biomass production, plant allometry and root characteristic of clones established through different lengths of cuttings is scarce.The experiment was performed with 2 common SRC clones (Populus clone Max 4, Salix clone Inger) and 2 cutting length (20 cm and 40 cm). Above- and belowground biomass and leaf and root morphology were determined after one growing season. Longer cuttings produce more biomass but have a diverging influence on the shoot:root allocation of both clones. Long cuttings of Populus cl. Max produce more aboveground biomass, mostly leaves, than 20 cm cuttings, while 40 cm Salix cl. Inger cuttings have more fine roots. Leaf and root morphology are only marginally influenced by cutting length.Choosing longer Populus cl. Max cuttings might not be a good strategy when considering SRC establishment on more stress-prone sites, since their larger above-ground biomass will e.g. increase transpirational demand. Because of the lower shoot:root ratio, longer Salix cl. Inger cuttings seem to be more suitable to establish SRC on fields with (partially) restricted water and nutrient supply than shorter cuttings. Thus, planting difficulties and higher costs of longer cuttings may be offset by higher survival and greater aboveground productivity only in some clones. In the future, optimal cutting lengths must be evaluated not only for different environmental conditions but also for different SRC species/clones.     

生态视角下的旧工业厂房空间改造探析

通过重新审视旧厂房改造的内在逻辑，结合生态理念对我国废旧厂房的改造实践从空间的改造上进行分析研究，发现我国现有改造实践中生态理念思考与运用的不足并提出参考性建议，以期促进改造设计的可持续发展。