Automatic fuzzy-rule assessment and its application to the modelling of nitrogen leaching for large regions

 Diffuse nutrient emissions from agricultural land is one of the major sources of pollution for ground water, rivers and coastal waters. The quantification of pollutant loads requires mathematical modelling of water and nutrient cycles. The deterministic simulation of nitrogen dynamics, represented by complicated highly non-linear processes, requires the application of detailed models with many parameters and large associated data bases. The operation of those models within integrated assessment tools or decision support systems for large regions is often not feasible. Fuzzy rule based modelling provides a fast, transparent and parameter parsimonious alternative. Besides, it allows regionalisation and integration of results from different models and measurements at a higher generalised level and enables explicit consideration of expert knowledge. In this paper an algorithm for the assessment of fuzzy rules for fuzzy modelling using simulated annealing is presented. The fuzzy rule system is applied to simulate nitrogen leaching for selected agricultural soils within the 23687 km² Saale River Basin. The fuzzy rules are defined and calibrated using results from simulation experiments carried out with the deterministic modelling system SWIM. Monthly aggregated time series of simulated water balance components (e.g. percolation and evapotranspiration), fertilization amounts, resulting nitrogen leaching and crop parameters are used for the derivation of the fuzzy rules. The 30-year simulation period was divided into 20 years for training and 10 years for validation, with the latter taken from the middle part of the period. Three specific fuzzy rule systems were created from the simulation experiments, one for each selected soil profile. Each rule system includes 15 rules as well as one prescribed rules from expert knowledge and 7 input variables. The performance of the fuzzy rule system is satisfactory for the assessment of nitrate leaching on annual to long term time steps. The approach allows rapid scenario analysis for large regions and has the potential to become part of decision support systems for generalised integrated assessment of water and nutrients in macroscale regions.     

An example of expert system on numerical modelling system in coastal processes

With the advent of artificial intelligence technology as well as the widespread popularity of desktop microcomputers in recent years, integration of this new technology with the traditional numerical modelling system becomes a current trend in order to solve various engineering problems. It renders a more intelligent and user-friendly system on the problem domain. In this paper, a knowledge-based expert system on numerical modelling system for coastal water processes is delineated. Expert system application, as a key branch of artificial intelligence technology, is integrated with traditional numerical modelling for simulating flow and water quality phenomenon in coastal waters. The knowledge bases are classified into five major types, namely, a variety of models, relations between various model parameters and real physical conditions, feasible options of model parameters, question base as a user-interface directing the user to depict the actual physical conditions, and the rules of inference deducing the feasible choice of model and its parameters. A hybrid expert system shell, Visual Rule Studio, is employed as an ActiveX Designer under Microsoft Visual Basic environment because it combines the advantages of both production rules and object-oriented programming technology. Both forward chaining and backward chaining are used collectively during the inference process, which is mainly driven by premises and conditions with the highest factors of confidence. The inference engine will drive the decision tree to explore the most probable option of numerical model and parameters matching the real problem specifications. It is shown that the application and integration of the knowledge-based expert system technology into numerical modelling for coastal processes can provide substantial assistance to novice users for selection of numerical model as well as parameters.     

MIKE 21: a modelling system for estuaries,coastal waters and seas

MIKE 21 is a comprehensive modelling system for the simulation of hydraulics and hydraulic-related phenomena in estuaries, coastal waters and seas. It can be applied to any two-dimensional free-surface flows where stratification can be neglected. The various modules of the system simulate hydrodynamics, advection-dispersion, short waves, sediment transport, water quality, eutrophication and heavy metals. The system has a wide range of engineering and environmental applications in coastal hydraulics, oceanography, wave dynamics, harbours, rivers, environmental hydraulics and sediment processes. An extensive pre- and post-processing module allows analysis and graphical presentation of both data and model results, which are stored in a simple data base. A flexible, interactive menu system facilitates data handling, model input and program execution. It runs on UNIX work stations including PC's with SCO UNIX operating system.     

空间相似查询中MBR边界区域关系研究

相似查询是基于向量空间的一种重要查询方法。点、线段、区域是向量空间对空间对象的三种基本表达。本文在不改变结点MBR区域前提下,通过区域扫描对MBR区域重叠面积进行计算。利用R*树结点MBR允许重叠的特性,在不能消除区域重叠产生的死空间情况下,研究了更为精确的MBR边界的线段关系,并给出线段的最近邻查询算法和相似线段选取算法。实验结果表明该方法的CPU计算代价较低且显著提高了相似查询与更新的效率。     

A case study of environmental modelling and simulation using transplantable components

Recent changes in environmental modelling practice have included adoption of modern software engineering concepts of model reuse, extensibility and flexibility, and development of better visual user interfaces. Additionally, the concepts of component-based software development and use of object-oriented programming have produced new environmental modelling methods. These changes have been supported by development of a range of modelling environments that allow rapid creation of environmental models from components. To date there has been little exploration of the opportunities that modelling environments offer in terms of flexible model construction by transplanting components. In the work reported here, simple catchment-based nonpoint source pollution models are constructed using the ICMS modelling environment, and a number of different data types and components are used within a single model structure to estimate pollution loads. Models include a bulk runoff-concentration load calculation, an export coefficient model, and land-use specific runoff and loads. It was found that, when applied using a powerful and flexible modelling environment, the component-based modelling concept provides not only an elegant method for model development, but also the opportunity to explore model expansion and refinement through use of transplantable components.     

基于物联网的城市河道酸碱度远程检测系统的设计

随着城市经济的发展，城市河道水环境受到了严重的污染和破坏，其中水质的酸碱度是水质污染的一个重要指标。由于城市河道水质污染的不确定性，一套能够在野外无人看管的环境下，多节点多范围对河道水质酸碱度实时检测系统成为一种需求。系统中每个采集节点连有pH传感器，采集的pH值数据通过Zigbee模块传给基站，基站将每个节点的数据与时间和地点信息绑定存储到云端数据库。管理人员可以通过网页随时随地了解当前各区域的水质酸碱度情况，如一旦水质出现污染，管理人员可以通过后台了解水质污染的扩散情况和污染源头，可以及时采取措施降低损失。该系统的运用与传统的人工现场取样带回实验室分析的方法相比，不但极大的提高了预警能力而且还大幅降低人力成本。     

Modelling pollution dispersion,the ecosystem and water quality in coastal waters: a review

This review is intended as a comprehensive but concise summary of present capabilities in coastal pollutant, ecosystem and water quality modelling. It reflects the recent rapid developments in multidisciplinary modelling in shelf seas.The behaviour of conservative pollutants that act as passive tracers is contrasted with those that have more complex behaviours, including oil spills. The importance of sediment modelling is emphasised, since contaminants commonly exist in both a dissolved and a particulate state, or adhere to sediments.Recently developed ecological models can have great complexity, reflecting the complexity of the real ecosystem. These models are now being linked to physical models of coastal waters and run with the same resolution. This has become possible only recently because of increases in computer power, particularly the availability of parallel systems at reasonable cost.The main advances in physical modelling are likely to come through greater understanding of turbulence and other sub-grid-scale processes as well as increased resolution.In the coastal seas there is often a lack of oceanographic data, which is even greater for the many biological and chemical variables than it is for physical variables. This is probably the single most important factor limiting the progress of operational water quality models.     

Prediction of river discharge and surface water quality using an integrated geographical information system approach

A methodology is developed for the prediction of river discharge and surface water quality (indexed by nitrogen loading) of a predominantly rural catchment using simple models in an integrated Geographical Information System (GIS). River discharge is predicted using the Soil Conservation Service (SCS) runoff Curve Number model, and surface water quality by the export coefficient model. Main input variable to these models is information on land-use along with ancillary information such as soils. Land-use is an important parameter that affects both discharge and water quality, and it can be derived from classification of remotely sensed images. Unlike conventional models, the models employed here do not require large amounts of data on several hydro-meteorological variables. The models are applied to a rural catchment in eastern England where major land-use changes have occurred in the recent past. Historical land-use data are derived from a variety of sources including maps, aerial photographs and remotely sensed satellite images for various dates ranging from 1931 to 1989. A GIS is a valuable means to enable large amounts of spatial data to be integrated, and to facilitate data manipulation for the specific application of the models. Results are validated using observed runoff and water quality records, and it is shown that the model predictions are of acceptable accuracy. This study demonstrated an application of a GIS to employ simple models to predict river discharge and water quality.     

Assessing pollution risks to water supply intakes using geographical information systems (GIS)

The process of pollution risk assessment requires the assimilation of data that are spatially variable in nature, making geographical information systems (GIS) an ideal tool for such assessments. Over half of Britain's drinking water is obtained from surface water abstractions, many of which are situated in upland areas. In order to optimise the quality of abstracted waters it is important to assess the possible risks of pollution upstream from the point of abstraction. This paper describes the use of the PC-based WINGS™ and MapInfo Professional™ geographical information systems in the evolution of a risk assessment methodology to assess catchment risk. The work illustrates how such technology can assist in environmental decision-making to optimise the quality of drinking water supplies and enhance treatment efficiencies. Examples are given showing how raster and vector-based data can be used within a GIS framework to produce maps indicating areas of potential hazard to water quality, and coupled with existing models to predict and quantify risk frequency and impact. GIS techniques are further utilised in the formulation of a raw water monitoring programme to assist in intake operation and land-use planning in the catchment. The availability of suitable digital data was found to be variable, and some problems encountered in their integration and implementation within the system framework were resolved. Comment is given on the suitability and relative performance of the two software packages in the assessment of catchment risk. The work was carried out on a medium specification desktop PC, and therefore has the potential to be utilised across the intranet of a large utility company.     

Modelling the distribution of radionuclides in a Mediterranean coastal ecosystem

The present paper deals with the modelling process in relation to the class of well-mixed compartment models (box models).A box model has been described and tested for radionuclides released by a BWR Nuclear Power plant (2 × 1000 MWe; under construction at Montalto di Castro, Central Italy) into the Tyrrhenian Sea.The model predicts the radionuclide transport between the most important components of the coastal marine ecosystem (water, pore-water, sediments and biota), but only the possibility of determining radionuclide concentrations associated with abiotic components is discussed.In the context of modelling, the requirements for information concerning the behaviour of radionuclides in a coastal ecosystem are discussed, with reference to chemical, physical and biological considerations.A validation for the radionuclide transport model was made using literature data on the Sellafield (Windscale) site. The major sources of uncertainty in the model were evaluated by sensitivity analysis and parameter imprecision analysis using site-specific parameter values obtained at Montalto di Castro.     

Coupling agent-based models of subsistence farming with individual-based forest models and dynamic models of water distribution

Subsistence farming communities are dependent on the landscape to provide the resource base upon which their societies can be built. A key component of this is the role of climate and the feedback between rainfall, crop growth, land clearance and their coupling to the hydrological cycle. Temporal fluctuations in rainfall alter the spatial distribution of water availability, which in turn is mediated by soil-type, slope and landcover. This pattern ultimately determines the locations within the landscape that can support agriculture and controls sustainability of farming practices. The representation of such a system requires us to couple together the dynamics of human and ecological systems and landscape change, each of which constitutes a significant modelling challenge on its own. Here we present a proto-type coupled modelling system to simulate land-use change by bringing together three simple process models: (a) an agent-based model of subsistence farming; (b) an individual-based model of forest dynamics; and (c) a spatially explicit hydrological model which predicts distributed soil moisture and basin scale water fluxes. Using this modelling system we investigate how demographic changes influence deforestation and assess its impact on forest ecology, stream hydrology and changes in water availability.     

Modeling the pathways and attenuation of nutrients from domestic wastewater treatment systems at a catchment scale

Domestic Wastewater Treatment Systems (DWTS) are often cited as significant sources of pollution in rural catchments. A mass balance based model has been developed to determine annual nutrient loading from individual DWTS into rivers in Ireland. The transport and attenuation of nitrogen and phosphorus in DWTS effluent to groundwater and surface water has been formulated using the results from field research in Ireland, as well as being informed by other international studies. Conceptually the model splits the transport of nutrients to the river into three pathways: direct to surface water (for areas of inadequate percolation), a near surface (subsoil) pathway, and a groundwater pathway. The model quantifies the net nutrient contribution for each DWTS and has been incorporated into a broader source load apportionment catchment model which includes agricultural inputs, thereby enabling the relative risk of nutrient pollution from DWTS in a catchment to be defined.     

The assessment of emission-source contributions to air quality by using a coupled MM5-ARPS-CMAQ modeling system: A case study in the Beijing metropolitan region,China

A coupled MM5-ARPS-CMAQ air quality modeling system was applied for investigating the contributions of various emission sources to the ambient concentrations of PM₁₀ in the Beijing metropolitan region of China. A three-level nested simulation domain was established for facilitating the modeling study, and a GIS-based atmospheric pollutant emission database was constructed to provide important emission information for the Models-3/CMAQ model. After verification, the coupled modeling system was implemented to predict the hourly contribution ratios of various PM₁₀ emission sources to Beijing's air quality during four representative months of January, April, August and October in the base year of 2002. It was found from the modeling results that three major sources (including fugitive industrial emissions, construction sites, and road dusts) presented a relatively high contribution to the PM₁₀ pollution in Beijing, with the contribution ratios of 28.67%, 42.88%, 42.46% and 35.67% for spring, summer, autumn and winter, respectively. In addition, the impacts of emissions from two major industrial zones within Beijing on its air quality were quantified. Moreover, the coupled modeling system was applied to explore possible future PM₁₀ concentration distributions in 2008 through two proposed emission sources reduction strategies. It was found that Beijing needs to take continual emission control efforts to comprehensively improve its air quality to the Class II level by 2008. The modeling results could provide sound decision making basis for developing effective air quality management strategies in the planning region.     

Nutrient monitoring,simulation and management within a major lowland UK river system: the Kennet

This paper describes an assessment of the nitrogen and phosphorus dynamics of the River Kennet in the south east of England. The Kennet catchment (1200 km²) is a predominantly groundwater fed river impacted by agricultural and sewage sources of nutrient (nitrogen and phosphorus) pollution. The results from a suite of simulation models are integrated to assess the key spatial and temporal variations in the nitrogen (N) and phosphorus (P) chemistry, and the influence of changes in phosphorous inputs from a Sewage Treatment Works on the macrophyte and epiphyte growth patterns. The models used are the Export Co-efficient model, the Integrated Nitrogen in Catchments model, and a new model of in-stream phosphorus and macrophyte dynamics: the ‘Kennet’ model. The paper concludes with a discussion on the present state of knowledge regarding the water quality functioning, future research needs regarding environmental modelling and the use of models as management tools for large, nutrient impacted riverine systems.     

Design of an expert system for water pollution determination/prevention

An initial model of an expert system was designed to provide quick responses for Slovenian river water pollution emergency situations by: identifying selected pollutants; planning immediate action to cope with urgent hazardous situations; identifying actual pollution source(s); and providing advice to reduce and prevent pollution at the source. The model knowledge base is implemented on the Knowledge. Pro communication system and is derived from two relational databases using the Informix.Sql relational database management system.     

An integrated catchment-coastal modelling system for real-time water quality forecasts

This paper presents a new marine water quality forecasting system for real-time and short-term predictions. The forecasting system comprises an integrated catchment-coastal model and a database management system. The integrated model is validated in an Irish catchment-coastal system using hydrodynamic and water quality data. The forecasting system was then used to provide short-term and real-time forecasts of Escherichia coli (E. coli) and Intestinal Enterococci concentrations (IE) in the near-shore coastal waters of Bray, Ireland. Two hind-cast scenarios were simulated: 5F in which predictions were based on rainfall forecasts only; and I-5F where forecasts of 5F were improved by incorporating real-time data. Results indicate that predictions of E. coli of scenario I-5F are improved. Also predicted IE concentrations by Scenario 5F were comparably higher than the I-5F predications, but due to the wide scatter of observed IE concentrations, the superiority of one scenario over the second could not be definitively determined.     

基于LabVIEW的水质监测中心软件设计

针对目前我国的水质污染情况严重,水质监测手段相对落后的现状,设计了基于LabVIEW的多功能水质监测上位机软件。系统采用网络通信方式,从物联网云平台上获取数据,并结合MATLAB、Access数据库和Elman神经网络技术,分别设计出了系统概述模块、数据接收模块、水质报警模块、数据存储模块、记录查询模块和数据预测模块,完成了数据接收、存储、查询、预测等功能。测试结果表明,该系统稳定可靠,各功能模块均能正常运行,达到了软件设计标准,实现了预期的功能。     

Application of partial mutual information variable selection to ANN forecasting of water quality in water distribution systems

Recent trends in the management of water supply have increased the need for modelling techniques that can provide reliable, efficient, and accurate representation of the complex, non-linear dynamics of water quality within water distribution systems. Statistical models based on artificial neural networks (ANNs) have been found to be highly suited to this application, and offer distinct advantages over more conventional modelling techniques. However, many practitioners utilise somewhat heuristic or ad hoc methods for input variable selection (IVS) during ANN development.This paper describes the application of a newly proposed non-linear IVS algorithm to the development of ANN models to forecast water quality within two water distribution systems. The intention is to reduce the need for arbitrary judgement and extensive trial-and-error during model development. The algorithm utilises the concept of partial mutual information (PMI) to select inputs based on the analysis of relationship strength between inputs and outputs, and between redundant inputs. In comparison with an existing approach, the ANN models developed using the IVS algorithm are found to provide optimal prediction with significantly greater parsimony. Furthermore, the results obtained from the IVS procedure are useful for developing additional insight into the important relationships that exist between water distribution system variables.     

A comparison of catchment water quality models and direct estimation techniques

Information on water quality, in particular on sediment, phosphorus and nitrogen exports from catchments, is required by catchment managers and other stakeholder groups to determine appropriate management options for water quality issues. However intensive spatial and temporal data on concentrations or loads of these nutrients is relatively scarce. Given this constraint, nutrient export models which can provide useful information on nutrient loads with only sparse data inputs are required. In addition, more complex physics and conceptually based models which are commonly available worldwide are often inappropriate for predicting loads in catchments. Consequently, models of a simpler conceptual and/or empirical type are used where input data are sparse and key processes are catchment dependent. This paper compares four such models (CMSS, AQUALM, Moss model and IHACRES-WQ) and several methods based on direct estimation for their ability to predict loads in Australian catchment situations. The implications of the limited available input data sets for load prediction in Australian catchments are discussed. In particular the importance of coordinated data collection over longer time periods and sufficiently fine temporal scales, covering a broad range of event sizes, is emphasised.     

棉纺质量控制专家系统的设计

主要研究棉纺质量控制专家系统的体系构成、棉纺质量控制知识的表示策略及知识库的设计。知识库的设计是该系统设计最重要的工作,包括基本数据库和规则库两方面。知识库的核心内容之一是基本数据库,用来存放质量问题的描述、产生原因、防止和处理办法等。规则库由质量问题库、质量问题影响因素、质量问题处理措施三个库构成。知识库的设计方法是先将棉纺质量控制知识抽象成概念、事实和规则,然后用关系数据库来存储这些知识。在此基础上构建一个基于产生式规则的专家系统。本系统采用基于规则的数据和信息驱动正向推理为主,辅之以目标驱动控制策略,算法采用深度优先。合理的知识库设计和有效的推理方法使得该系统效果较好。