Assimilation of virtual wide swath altimetry to improve Arctic river modeling

Global surface water variations are still difficult to monitor with current satellite measurements. The future Surface Water and Ocean Topography (SWOT) mission is designed to address this issue. Its main payload will be a wide swath altimeter which will provide maps of water surface elevations between 78°S and 78°N over a 120 km swath. This study aims to combine coupled hydrologic/hydraulic modeling of an Arctic river with virtual SWOT observations using a local ensemble Kalman smoother to characterize river water depth variations. We assumed that modeling errors are only due to uncertainties in atmospheric forcing fields (precipitation and air temperature) and different SWOT orbits were tested. First, we tested orbits that all have a three day repeat period but differ in terms of their spatial coverage of the study reach; these orbits correspond to the first three months of the mission, which will be dedicated to calibration and validation experiments. For these orbits, the mean spatial Root Mean Square Error (RMSE) in modeled channel water depth decreased by between 29% and 79% compared to the modeled RMSE with no assimilation, depending on the spatial coverage. The corresponding mean temporal RMSE decrease was between 54% and 91%. We then tested the nominal orbit with a twenty two day repeat period which will be used during the remaining lifetime of the mission. Unlike the three day repeat orbits, this orbit will observe all continental surfaces (except Antartica and the northern part of Greenland) during one repeat period. The assimilation of SWOT observations computed with this nominal orbit into the hydraulic model leads to a decrease of 59% and 66% in the mean spatial and temporal RMSE in modeled channel water depth, respectively. These results show the huge potential of the future SWOT mission for land surface hydrology, especially at high latitudes which will be very well sampled during one orbit repeat period. Still, further work is needed to reduce current modeling uncertainties and to better characterize SWOT measurement errors.     

Modelling climate change in a Dutch polder system using the FutureViewR modelling suite

This paper describes the development of a hydrological modelling suite, FutureViewR, which enables spatial quantification of the complex interaction between climate change, land use and soil in the Quarles van Ufford (QvU) polder entangled in and under influence of the Dutch river delta. The soil–water–atmosphere–plant (SWAP) model is used in a grid-based mode. A river module was developed to take into account seepage and percolation in the polder as an effect of the interaction with the main rivers. A simple surface water model was linked to the grid-based SWAP models. The model suite is managed from a Visual Basic (VB) interface which links the different modules. The interface uses a mainstream database management system (MS SQLServer), structured query language (SQL) and open database connectivity (ODBC) to store, transfer, manipulate and analyse model inputs and outputs. The functionality of the FutureViewR modeling suite is demonstrated by modeling a climate change scenario for 2050. The preliminary analysis showed that it is likely that the dryer summers in combination with low water levels in the Rhine and Meuse will yield a decrease in agricultural production. The wetter winters do not necessarily result in an increase in discharge, since the initial soil moisture storage at the winter onset is lower due to the dryer summers. It is concluded that the effects of climate change on polder hydrology is more intense caused by the dependence on local climate conditions and water levels on the Rhine and Meuse rivers, which are mutually reinforcing.     

Comparison of fire temperature and fractional area modeled from SWIR, MIR, and TIR multispectral and SWIR hyperspectral airborne data

Spectral mixture modeling has previously been used to retrieve fire temperature and fractional area from multiband radiance data containing emitted radiance from fires. While this type of temperature modeling has potential for improving understanding of fire behavior and emissions, modeled temperature and fractional area may depend on the wavelength region used for modeling. Using airborne hyperspectral (Airborne Visible Infrared Imaging Spectrometer; AVIRIS) and multispectral (MODIS/ASTER Airborne Simulator; MASTER) data acquired simultaneously over the 2008 Indians Fire in California, we examined changes in modeled fire temperature and fractional area that occurred when input wavelength regions were varied. Temperature and fractional area modeled from multiple MASTER runs were directly compared. Incompatible spatial resolutions prevented direct comparison of the AVIRIS and MASTER model runs, so total area modeled at each temperature was used to indirectly compare temperature and fractional area retrieved from these two sensors. AVIRIS and MASTER model runs using shortwave infrared (SWIR) bands produced consistent fire temperatures and fractional areas when modeled temperatures exceeded 800 K. Temperatures and fire fractional areas were poorly correlated for temperatures below 800 K and when the SWIR bands were excluded as model inputs. The single temperature blackbody assumption commonly used in mixing model retrieval of fire temperature is potentially useful for modeling higher temperature fires, but is likely not valid for lower temperature smoldering combustion due to mixed radiance from multiple fuel elements combusting at different temperatures. SWIR data contain limited emitted radiance from combustion at lower temperatures, and are thus essential for consistent modeling of fire temperature and fractional area at higher fire temperatures.     

基于面向对象方法的视图建模及分析

在运用面向对象的方法和基于统一建模语言(UML)建模机制的基础上,分析了系统模型的体系结构,给出了新的建模方法,选择视图方式之后采用了静态建模和动态建模两种建模机制,并将两种建模以视图模型的形式体现,为传统的建模方法引入新的方法和思路。     

Integrated assessment model of society-biosphere-climate-economy-energy system

The feedback based integrated assessment model ANEMI_2 represents the society-biosphere-climate-economy-energy system of the earth and biosphere. The ANEMI_2 model is based on the system dynamics simulation approach that (a) allows for the understanding and modeling of complex global change and (b) assists in the investigation of possible policy options for mitigating, and/or adapting to changing global conditions within an integrated assessment modeling framework. This paper outlines the ANEMI_2 model and its nine system components: climate, carbon cycle, land-use, population, food production, hydrologic cycle, water demand, water quality, and energy-economy. To evaluate market and nonmarket costs and benefits of climate change, the ANEMI_2 model integrates an economic optimization approach, with a focus on the international energy stock and fuel price, climate interrelations and temperature change. The model takes into account all major greenhouse gases (GHG) influencing global temperature and sea-level variation. Results from several scenarios (a) compare well with other information available in the scientific literature, (b) present comprehensive response of the society-biosphere-climate-economy-energy system to the selected scenarios, and (c) confirm the support role of the ANEMI_2 model in the policy development and analyses.     

基于元模型的知识管理建模工具设计与开发

知识管理建模是构建组织知识管理系统的基础．组织知识管理建模远比信息管理建模复杂，迫切需要建模工具的支持．从知识内容和管理两个层面分析提出知识管理的建摸需求，以此为依据建立知识管理元模型．组织知识管理元模型包括组织战略、组织结构、组织流程和组织知识地图四个子模型．为了方便建模工具的开发，用组织知识管理对象建模语言集成各子模型对应的建模语言．在此基础上实现了一个知识管理建模工具．     

Combining watershed models and knowledge-based models to predict local-scale impacts of climate change on endangered wildlife

Climate change is expected to have significant impacts on native, threatened and endangered wildlife. Understanding and modeling these impacts useful for wildlife managers, however, remain difficult due to complex climate change, and costly and high data requirements. Consequently, we proposed an easily-interpretable and data-efficient decision support approach to understand climate change impacts on the abundance of three endangered wetland birds (Hawaiian Stilt, Hawaiian Coot and Hawaiian Moorhen). We coupled a watershed model, AnnAGNPS, and ecological models using fuzzy-cognitive mapping software, Mental Modeler, in Hanalei watershed, Kauaʻi. Results suggested that increased precipitation would increase Stilt abundance, but decrease Coot and Moorhen abundance. Decreasing precipitation might have negative effects for all three species. Moreover, decision-makers should pay equal attention to controlling components (water depth, food availability and disease) with system-wide influence. Finally, besides being adaptable to similar environmental contexts, our approach captured both direct and indirect climate change impacts through ecological connectivity.     

基于XML和Agent联邦的工作流建模方法

介绍一种基于XML和Agent联邦的工作流建模方法，目的在于建立分布式环境下灵活的，动态的工作流管理过程。该方法将工作流管理系统组织成一个可能嵌套的Agent联邦，将工作流定义为一个由Agent联邦协同完成的活动集合。面向活动分担的联合意向是Agent进行工作流规划的依据与手段，它成功地解决了工作流过程分解的静态性与工作流过程运行的动态性之间的矛盾。文中方法采用的过程建模语言是建立在XML的基础上，与传统的过程建模语言相比，它具有更强的可操作性与可扩展性。最后介绍了工作流建模环境以及利用该环境进行工作流建模的过程与步骤。     

Eye movement as a mediator of the relationships among time pressure,feedback, and learning performance

The goal of this study is to examine the effects of time pressure and feedback on learning performance, as mediated by eye movement. Time pressure is one of main causes of human error in the workplace. Providing participants with feedback about their performance before task completion has been shown to reduce human error in diverse domains. Since both time pressure and feedback induce motivation, which is closely related to attention, we measured participants' eye movements to trace their attention and information acquisition coupled with a visual display. Time-to-deadline (long and short) and the presence of feedback were the independent factors used while measuring participants’ performance and eye movements as they learned new information about the subject of project management and answered multiple-choice questions via self-paced online learning systems. Using structural equation modeling, we found a mediating effect of eye movement on the relationships among time-to-deadline, feedback, and learning performance. Insufficient time-to-deadline accelerated the number of fixations on the screen, which resulted in longer task completion times and increased correct rates for participants learning about project management. The models in this study suggest the possibility of predicting performance from eye movement under time-to-deadline and feedback conditions. The structural equation model in the study can be applied to online and remote learning systems, in which time management is one of the main challenges for individual learners.     

面向水库型小流域的多源水利三维建模方法研究

针对大型河道三维可视化建模中采用激光雷达、声呐等传感器获取水下地形建模方式操作复杂且成本较高的缺陷,在利用基础测绘成果构建实景地形模型的基础上,采用多源三维模型融合方法对月塘水库小流域进行实景建模。首先采用倾斜摄影三维建模技术对重点水利工程进行实景建模,并利用专业建模软件对重要控制单元进行构件级建模;然后利用已有河道断面数据结合河流面状矢量数据,实现流域内胥浦河河道实景三维建模;最后通过人机交互方式对多源实景模型进行微调与相互印证,实现月塘水库小流域多源三维模型精准融合构建。研究成果可为河道型水库的预报调度与洪水风险分析提供可视化模型基础与决策支撑。     

An open-book watershed model for prototyping space-borne flood monitoring systems in International River Basins

A new era involving both simple and complex hydrologic modeling of un-gauged river basins may now emerge with the anticipated global availability of high resolution satellite rainfall data from the proposed Global Precipitation Measurement (GPM) mission. This era of application pertains to rapid prototyping of GPM-based flood monitoring systems for downstream nations in International River Basins (IRBs) where basin-wide in-situ rainfall data is unavailable due to lack of either an infrastructure or a treaty for real-time data sharing with upstream riparian nations. In this paper, we develop, verify and apply an open-book watershed model for demonstrating the value of a parsimonious modeling scheme in quick prototyping of satellite rainfall-based flood monitoring systems for lowermost nations in flood-prone IRBs. The open-book watershed modeling concept was first formulated by Yen and Chow [1969. A laboratory study of surface runoff due to moving rainstorms. Water Resources Research 5(5), 989–1006] more than 30 years ago as a convenient and pragmatic framework to understand the underlying physics behind surface hydrologic phenomena. Our developed model is based on first principles of conservation of mass and momentum that parsimoniously represents the static geophysical features of a basin with minimum calibration. Such a generic and parsimonious representation has the added potential to supplement complex hydrologic models for stakeholder involvement and conflict management in transboundary river basins, among many additional applications. We first demonstrate the physical consistency of our model through sensitivity analysis of some geophysical basin parameters pertinent to the rainfall-runoff transformation. Next, we simulate the stream-flow hydrograph for a 4-month long period using basin-wide radar (WSR-88D) rainfall data over Oklahoma assuming an open-book river basin configuration. Finally, using the radar-simulated hydrograph as the benchmark, and assuming a two-nation hypothetical IRB over Oklahoma, we explored the impact of assimilating NASA's real-time satellite rainfall data (IR-3B41RT) over the upstream nation on the flow monitoring accuracy for the downstream nation. We developed a relationship defining the improvement in flow monitoring that can be expected from assimilating IR-3B41RT over transboundary regions as a function of the relative area occupied by the downstream nation for a semi-arid region. The relative improvement in flow monitoring accuracy for the downstream nation was found to be clearly high (over 35% reduction in root mean squared error) when more than 90% of the basin is transboundary. However, flow monitoring accuracy reduces considerably and even becomes negative when 60% or less of the basin area is transboundary to the downstream nation. Our findings, although hypothetical and very regime-specific, illustrate very clearly the feasibility of utilizing anticipated GPM data to alleviate the current flood monitoring limitations experienced by many nations in IRBs through the application of a generic and parsimonious model.     

WODA - a modeling support system for BOD-DO assessment in rivers

This paper describes a modeling support system (WODA) which allows the computation of BOD and DO concentrations in a river stretch under different hydrological and thermal conditions. The support is based on a model in which the reaction rates depend upon flow rate and temperature. Peculiar characteristics of WODA are the possibility to estimate the model parameters on the basis of a few sets of data and the availability of an interactive simulation routine. A built in data base for storing and managing water quality data is currently being developed.     

基于B/S结构的学生评教系统的设计与实现

学生评教系统是适用于高等院校教师课堂教学质量管理的应用软件。在需求分析过程中,将整个系统分为学生评教模块、教师评学模块、教师互评模块和后台管理模块,使用统一建模语言UML对系统进行面向对象的分析和建模,完成了系统的静态建模,系统采用B/S结构开发,在校园网上进行测试,实现了预期目标。     

DCworms – A tool for simulation of energy efficiency in distributed computing infrastructures

In the recent years, energy-efficiency of computing infrastructures has gained a great attention. For this reason, proper estimation and evaluation of energy that is required to execute data center workloads became an important research problem. In this paper we present a Data Center Workload and Resource Management Simulator (DCworms) which enables modeling and simulation of computing infrastructures to estimate their performance, energy consumption, and energy-efficiency metrics for diverse workloads and management policies. We discuss methods of power usage modeling available in the simulator. To this end, we compare results of simulations to measurements of real servers. To demonstrate DCworms capabilities we evaluate impact of several resource management policies on overall energy-efficiency of specific workloads executed on heterogeneous resources.     

Syntax highlighting in business process models

Sense-making of process models is an important task in various phases of business process management initiatives. Despite this, there is currently hardly any support in business process modeling tools to adequately support model comprehension. In this paper we adapt the concept of syntax highlighting to workflow nets, a modeling technique that is frequently used for business process modeling. Our contribution is three-fold. First, we establish a theoretical argument to what extent highlighting could improve comprehension. Second, we formalize a concept for syntax highlighting in workflow nets and present a prototypical implementation with the WoPeD modeling tool. Third, we report on the results of an experiment that tests the hypothetical benefits of highlighting for comprehension. Our work can easily be transferred to other process modeling tools and other process modeling techniques.     

Toward improved simulation of river operations through integration with a hydrologic model

Advanced modeling tools are needed for informed water resources planning and management. Two classes of modeling tools are often used to this end–(1) distributed-parameter hydrologic models for quantifying supply and (2) river-operation models for sorting out demands under rule-based systems such as the prior-appropriation doctrine. Within each of these two broad classes of models, there are many software tools that excel at simulating the processes specific to each discipline, but have historically over-simplified, or at worse completely neglected, aspects of the other. As a result, water managers reliant on river-operation models for administering water resources need improved tools for representing spatially and temporally varying groundwater resources in conjunctive-use systems. A new tool is described that improves the representation of groundwater/surface-water (GW-SW) interaction within a river-operations modeling context and, in so doing, advances evaluation of system-wide hydrologic consequences of new or altered management regimes.     

土壤水热耦合运移数值模型研究进展

土壤水热耦合运移的数值模型研究是在二十世纪五十年代在等温水分运动模型的基础上发展起来的 ,该模型的建立不仅可用于预测农田水热的分布情况 ,从而为农业生产决策服务 ,而且可用于工业生产建筑中的地下产热问题和垃圾填埋场土地填筑中垃圾腐化产热问题的解决 ,因而具有广泛的应用价值 .本文对五十年代以来国内外土壤水热耦合数值模型的主要研究发展进行了介绍 ,并指出现今的模型应注意的问题 .