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关键词： Flow-induced sound   Immersed boundary method   Moving boundary   Bio-inspired locomotion   Computational aero/hydro-acoustics  

摘要： A hybrid approach based on the immersed boundary method (IBM) is developed for computation of flow-induced sound around moving bodies. In this method, a high-fidelity direct numerical simulation (DNS) solver is used to simulate the incompressible flow field. The sound field is predicted by discretizing acoustic perturbation equations (APEs) with dispersion-relation-preserving space scheme and low-dispersion and low-dissipation Runge-Kutta time integration. A sharp-interface IBM based on ghost-cell is implemented for present two-step DNS-APE approach to deal with complex moving bodies with Cartesian grids. The present method is validated through simulations of sound generation caused by flow past a rotating cylinder, an oscillating cylinder, and tandem oscillating and stationary cylinders. The sound generated by typical kinds of complicated bio-inspired locomotions, i.e., flapping flight by wings of varied shapes and collective undulatory swimming in tandem, are investigated using present method. The results demonstrate potential of the hybrid approach in addressing flow-induced sound generation and propagation with complex moving boundaries in a fluid medium, especially for the sound characteristics of bio-mimetic flows, which might shed lights on investigations on bio-acoustics, ethology of complex animal system, and related bio-mimetic design for quietness.

关键词： Industrial air pollution   Climate-oriented production system   Environmental monitoring   Machine learning   Artificial neural network   Forecast   Predictive model   IoT   Lagrangian dispersion  

摘要： The paper is devoted to solving the problem, associated with increasing the forecasting accuracy of pollutant concentration level based on PM25 dust. The LANN model (LANN - Lagrange powered Artificial Neuron Network), proposed in the paper, allows you to take into account the mutual influence of pollution sources on the concentration level at monitoring points, which, on the one hand, allows to manage the volume of emissions from industrial enterprises in such away as to avoid penalties and, on the other hand, allows the regulatory agencies to determine points for environmental control, at which permissible standards will be most likely exceeded. The suggested solution makes it possible to use low-cost IoT-based air quality monitoring devices, which were primarily considered not applicable due to their low accuracy and exposure to the influence of short-term stochastic factors;besides, no models were available, which would be capable to provide the necessary accuracy and forecast horizon on the base of IoT data. At the same time, the obtained model has low requirements for computing resources compared to dispersion models and is dependent on the accuracy of weather information;besides, the model allows you to take into account trends and obtain better forecast values in terms of accuracy than the models, that use regression methods, neural network models and ML models, stochastic models and their ensembles. The application of the model improves well-known pollutant dispersion estimation calculation techniques through the use of measurement data flow and dynamic adaptation to changing conditions. The model was trained on the dataset over the period 2022-2023 collected from 5 monitoring devices, which were installed in the catchment area of the group, incl. 13 industrial points of PM25 pollutant sources.

摘要： 本产品具有国内行业中质量检验的权威性 长期、周到的售后服务让客户无后顾之忧 松香色度标准装置(又名《松香颜色分级标准》玻璃比色块),是符合我国松香光学特性具有完整体系的松香颜色分级标准.1982年荣获林业部科技成果二等奖.1987年至今,被《脂松香》、《松香试验方法》国家标准所采用,并多次经国家质量监督检验检疫总局复查考核合格.

关键词： 圆柱绕流   气动噪声   大涡模拟   FW-H声类比   边界条件  

摘要： 为研究边界条件对三维、常物性、非定常、单圆柱空气绕流湍流气动噪声的影响，采用基于大涡模拟（Large Eddy Simulation,LES）结合Ffowcs Williams and Hawkings (FW-H)声类比的方法，在单圆柱绕流气动噪声数值模拟方法验证的基础上，数值模拟研究四组不同边界条件下单圆柱近、远场气动噪声辐射特性。比较基准算例的数值模拟结果与文献试验结果可知，当计算域的入流面、出流面和展向侧面的边界条件设为自由流，而垂向顶面和底面为充分发展的周期性边界时，能够较好地预测声压级（Sound pressure level,SPL）频率及其对应峰值，与试验结果吻合较好。进一步分析表明，与其他三种对照组的边界条件相比，计算域的入流面、出流面和展向侧面为自由流边界，即流向与展向边界上无声反射的边界条件更适合用于此类气动噪声的数值模拟。本文结论为类圆柱体、多圆柱体或更加复杂的各种柱体结构气动噪声数值模拟提供了一种可行的边界条件设置方法。

关键词： 渔业   监管   无人船   环境监测   智能投喂  

摘要： 随着智慧渔业的发展，现代渔业中运用的无人船越来越多。近年来，无人船凭借出色的自主航行和路径规划能力，既实现了传统渔业监测和监管的功能，又弥补了人工监管成本高、效率低的缺陷，拓宽了无人船在渔业中的应用范围，显示出巨大的应用潜力。该文系统阐述了无人船在渔业智慧监管中的应用，包括自主航行、路径规划、水环境监测和水产养殖等方面的关键技术，并分析了其未来研究方向。分析表明，无人船搭载高分辨率传感器和智能系统，可实现对渔船活动的实时监测和非法捕捞行为的自动识别，提高监管效率和准确性，同时减少人力需求和降低运营成本。在水环境监测中，无人船提高了监测的实时性和精确度，减少了设备投入和相关成本，并在恶劣环境中表现出色。在水产养殖中，无人船的智能投喂和施药技术提升了养殖效率和生物健康水平，降低了养殖成本。最后讨论了无人船在渔业应用中的机遇和挑战，认为其在低成本制备、多功能集成、新技术开发和应用场景挖掘等方面具有较大的发展潜力，同时指出提高无人船在复杂条件下的稳定性和可靠性、设计多参数一体化检测系统、开发可靠的自供电模块和拓展应用场景是无人船在智慧渔业领域的重要发展方向。

关键词： 预算维护   近质心近邻   核方法   在线分类   标签噪声  

摘要： 核方法被开发用于处理在线分类中的非线性分类问题，计算核函数时为了避免支持向量的数量随数据流而无限增加，近年来发展了预算维护算法。现有的固定预算的核分类算法在分类性能上会受标签噪声的严重影响。为了解决该问题，提出一种基于kNCN的标签噪声在线核学习方法。当缓冲区达到预算规模时，该方法利用kNCN原则为缓冲区内每个支持向量找到k个近质心近邻点，通过计算它们之间的局部标签不一致性来构建删除候选集和锚点集，再对删除候选集内所有实例建立试错模型，在锚点集上检验试错模型的分类准确率，从而判断哪个支持向量最应该从缓冲区中删除，实现固定预算的维护。人工合成数据集和真实数据集上的实验结果表明，本方法在固定预算的感知机和被动攻击算法上的应用，在标签噪声场景下有效提升了分类性能，在6个数据集上的综合排名优于其他对比算法。

关键词： 一体化设备   CFD模拟   溶解氧   PID控制   脱氮  

摘要： 针对当前养殖废水传统处理工艺成本高、效率低和占地面积大等问题，采用CFD模拟技术设计了一种利用水动力循环回流的一体化污水处理系统。通过有限元模拟寻优设备空间几何结构，设计了一种新的污水生化处理单元回流方式，减少了动能设备的数量和能耗。构建了模糊自适应PID控制系统，精准控制各单元的溶解氧浓度，可减少生物反应池溶解氧波动幅度。模拟结果表明，当厌氧池至缺氧池与缺氧池至好氧池的开口比为4:1时，池体剖面的流速分布比较均匀，流体的循环可以避免形成死水区，从而减少污泥沉积。试验结果表明，研制的一体化系统运行稳定，可连续监测数据，COD、氨氮和TN去除率分别达98.76%、97.57%和96.43%，溶解氧能耗降低了20%。

关键词： 负荷建模   类噪声信号   频域分析   负荷响应特性  

摘要： 负荷时变性是制约负荷建模发展的难点之一，而基于类噪声的负荷建模方法为克服该难题提供了新的解决思路。但是，类噪声和传统大扰动性质不同，负荷随机波动在类噪声中作为重要扰动源难以忽略，导致了实测类噪声数据和典型负荷模型间频域性质的差异，也影响了基于类噪声负荷建模方法的效果。因此，本文研究内部扰动存在对负荷节点响应的影响，以解释频域差异的可能原因，同时分析类噪声激励下不同频段的内部扰动对负荷响应的影响强弱，并提出一种基于滤波的负荷辨识改进方法。最后，基于仿真验证了负荷特性分析和改进方法的有效性。结果表明，滤波能提取有效负荷响应，改善类噪声负荷辨识效果。