环厦门海域水色变化的多光谱多时相遥感分析

采用基于影像光谱信息建立的水质遥感模型对环厦门海域1989～2003年间的水色变化进行了分析.通过对水体及其所含物质的物理光学性质分析,水质遥感模型的建立可以不依赖于和卫星同步的水质采样数据建立水质遥感.这使得遥感对水色分析的应用更容易,而且还可以利用大量卫星存档数据来进行水质的历史变化分析.使用基于可见光和近红外波段反射率创建的模型研究了离水信号和水中物质(悬浮物和浮游植物)的关系.提出了一套可用于Landsat TM/ETM 和SPOT 5影像的水专题处理流程,并用于揭示所研究海域中悬浮物和叶绿素浓度的时空变化规律.研究表明,利用基于影像光谱的水质遥感模型,可以快速有效地揭示长时间范围内水色的时空变化.总的看来,环厦门海域的悬浮物浓度在所研究的时期内,有显著的增加,叶绿素的浓度在局部也有明显的升高.最明显的是,高悬浮物浓度的海域面积所占的比例从1989年的0.2%上升到2003年的10.2%.综合分析表明,九龙江河口所带来的巨量悬浮物是该海域最主要的陆源排海物和污染源,过度的水产养殖是另一个主要的污染因子.     

遗传梯度法在水质数学模型参数估值的应用

介绍一种混合遗传算法－－遗传梯度法，并将其应用于水质数学模型参数估值，较一般优化算法能稳定得到的全局最优解。     

Modelling dynamics of managed tropical rainforests—An aggregated approach

The overuse of rainforests in the last century and its consequences necessitate a rethinking of logging policies. To this end models have been developed to simulate rainforest dynamics and to allow optional management strategies to be evaluated. Parameterisation of presently existing models for a certain site needs a lot of work, thus the parameterisation effort is too high to apply the models to a wide range of rainforests. Hence, in this paper we introduce the simplified model FORREG using the knowledge we have gained from a more complex model, FORMIX3-Q.     

Use of genetic algorithms to select input variables in decision tree models for the prediction of benthic macroinvertebrates

Predicting freshwater organisms based on machine learning is becoming more and more reliable due to the availability of appropriate datasets, advanced modelling techniques and the continuously increasing capacity of computers. A database consisting of measurements collected at 360 sampling sites in non-navigable watercourses in Flanders was applied to predict the absence/presence of benthic macroinvertebrate taxa by means of decision trees. The measured variables were a combination of physical–chemical (temperature, pH, dissolved oxygen concentration, conductivity, total organic carbon, Kjeldahl nitrogen and total phosphorus), structural (granulometric analysis of the sediment, width, depth and flow velocity of the river) and two ecotoxicological variables. The predictive power of decision trees was assessed on the basis of the number of Correctly Classified Instances (CCI). A genetic algorithm was introduced to compare the predictive power of different sets of input variables for the decision trees. The number of input variables was reduced from 15 to 2–8 variables without affecting the predictive power of the decision trees significantly. Furthermore, reducing the number of input variables allowed to ease the identification of general data trends.     

AGA法及其在非线性数学模型参数估计中的应用

介绍了在基因算法基础上改进的加速基因算法（ＡＧＡ），并通过环境非线性数学模型参数估计实例对该法与传统参数估计方法进行了比较。初步结果表明，ＡＧＡ法直观、简便、拟合精度高、通用性强，易为广大环境工程技术人员理解和使用。     

基于ISODATA算法的水上交通事故黑点识别

针对水上交通安全问题,基于ISODATA算法和水上交通事故等级综合加权平均法,构建水上交通事故黑点识别模型。结合道路交通黑点及现有水上交通多发区的研究方法,定义水上交通事故黑点;采用ISODATA算法分析水上交通事故空间分布特征,实现对水上交通事故空间的构建;对水上交通事故等级梯度赋值,以量化事故的严重程度,利用等级综合加权平均法确定黑点阈值。并以深圳西部港区水上交通事故为例进行模型应用,共识别出10处事故黑点及其边界,表明水上交通黑点识别模型能有效识别水上交通黑点的空间分布及特征,为水上交通安全状态分析提供了一种度量方法。     

Dynamic temperature model for proton exchange membrane fuel cell using online variations in load current and ambient temperature

This paper presents a dynamic temperature model for a proton exchange membrane fuel cell (PEMFC) system. The proposed model overcomes the complexity of conventional models using first-order expressions consisting of load current and ambient temperature. The proposed model also incorporates a PEMFC cooling system, which depends upon the temperature difference between events. A dynamic algorithm is developed to detect load changing events and calculate instantaneous PEMFC temperature variations. The parameters of the model are extracted by employing the lightning search algorithm (LSA). The temperature characteristics of the NEXA 1.2 kW PEMFC system are experimentally studied to validate model performance. The results show that the proposed model output and the temperature data obtained from experiments for linear and abrupt changes in PEMFC load current are in agreement. The root-mean-square error between the model output and experimental results is less than 0.9. Moreover, the proposed model outperforms the conventional models and provides advantages such as simplicity and adaptability for low and high sampling data rates of input variables, namely, load current and ambient temperature. The model is not only helpful for simulations but also suitable for dynamic real-time controllers and emulators.     

碳市场发电企业违约分级累进处罚机制研究

在确保减排效率的前提下,以全国碳市场中的发电企业为研究对象,以实现碳市场经济剩余最大化为目标,构建政府和双寡头企业的两阶段动态博弈模型,研究分级累进处罚机制对大型和小型企业发电量、利润的影响,以及在实行分级累进处罚机制的碳市场中经济剩余的实现.算例结果表明：随着罚款系数的增加,违约企业是大型发电企业时,总发电量、企业总利润和经济剩余大幅减少7.47%、15.34%、5.88%;违约企业是小型发电企业时,总发电量小幅减少1.43%,企业总利润小幅减少3.39%或上升0.03%,经济剩余小幅上升0.13%;大型违约企业未参与碳交易时,企业总利润大幅减少16.35%,参与碳交易时,企业总利润小幅减少15.34%;小型违约企业未参与碳交易时,企业总利润大幅减少3.39%,参与碳交易时,企业总利润小幅上升0.03%,分级累进处罚机制能够有效的遏制企业的违约行为.因此,在设计发电行业处罚机制时,应加大处罚力度;设置分级累进处罚机制,分别根据企业规模和碳市场参与度进行分级和累进,并建立有效的监管制度.     

飞机典型液压管路系统减振优化计算方法研究

目的研究管道走向和卡箍位置对管道应力的影响。方法以飞机典型液压管路系统为优化对象,对管路系统及支持结构进行动力学参数化建模,使用MATLAB和MSC.NASTRAN构筑基于遗传算法的自动减振优化计算平台,以管壁结构和飞机支持结构的动态应力响应最小为优化目标,对管路走向(包括拐折位置、曲率半径)、卡箍位置进行优化计算,从而建立一种飞机管路系统设计中的自动减振优化计算方法。结果使用建立的减振优化计算平台优化计算设计后,飞机典型液压管路系统最大动态应力值降低了50%。结论提供的优化方法能够有效地通过优化管道布置参数降低应力水平。     

基于改进FWA-NN的污水处理过程溶解氧浓度预测

为实现对污水处理过程溶解氧质量浓度的实时准确预测,提出了一种改进的混沌烟花混合优化算法并构建了基于改进算法的神经网络在线软测量模型.结合污水处理过程的数据特征,定义了一项新的样本相似度衡量指标用于提取更具代表性的建模数据.在改进算法中,为提高基本烟花算法初始成员的质量,定义了一种改进的两级正弦混沌映射并利用混沌运动的遍历性精选烟花算法的初始群成员;通过融合混沌算法改进了基本烟花算法的搜索机制,基于设定准则将寻优过程分为两阶段并采用两分群同时进行.测试结果表明改进算法的收敛速度和收敛精度有较大程度提高.将改进的软测量建模方法和样本数据提取方法用于污水处理过程溶解氧质量浓度软测量建模,应用结果表明该模型的均方根误差和平均泛化误差分别为0.0175和0.0118,具有较强的泛化性能.