11 research outputs found
Calibration of the 2UP model: Spinlab Research Memorandum SL-13
Get PDFThe 2UP model – to an Urban Preview – is developed for the spatially explicit simulation of the future growth of cities and population at a global scale. The model describes urban land use at a fine 30” spatial resolution (approx. 1km near the equator). In the current version of the model, the allocation of urban land use is mainly based on current population densities. To improve this calibration PBL has requested Vrije Universiteit Amsterdam to apply a more advanced, statistics-based calibration procedure that links observed land-use patterns to spatially explicit drivers of urban development. The output of this calibration effort can be used to define the suitability for urban and in the 2UP model. This short memo describes the method applied in calibration and discusses the results
Evaluating the impact of road infrastructure on household income in Papua New Guinea: Spatial data compilation and analysis
Get PDFAs part of the ADB sub‐project ‘Developing Impact Evaluation Methodologies, Approaches, and Capacities in Selected Developing Member Countries’ two closely related research projects were carried out by VU to evaluate the impact of road infrastructure on household income in Papua New Guinea. One project focused on econometric analysis (contract no. 117629‐S85196), while the other developed the spatial database needed for this analysis (contract no. 117642‐S84962). The current report documents the data collection process and provides a concise description of the data that were collected for the project and the analyses that were performed to enrich the available data sources to create meaningful variables for the statistical analysis. It serves as a background document with the scientific paper‐that concisely describes the findings of the two joint research projects
Verkenning van de toepassingsmogelijkheid van floating car data voor het beschrijven van verplaatsingsgedrag
Get PDFDe toenemende beschikbaarheid van nieuwe (big) databronnen en data sciences methoden opent mogelijkheden om op een alternatieve manier verplaatsingsgedrag in termen van herkomst en bestemming, verplaatsingsmotief en routekeuze te analyseren. Dit onderzoeksproject heeft verkend in hoeverre het mogelijk is om floating car data te gebruiken om analyses naar de betrouwbaarheid van reistijden uit te voeren. Het doel hiervan is om die informatie te gebruiken bij het actualiseren en verbeteren van de verkeer‐en vervoermodellen van Rijkswaterstaat
Robust Nonlinear Spacecraft Attitude Control: An Incremental Backstepping Approach
No full textIn order to meet requirements in terms of robustness, stability, and performance for future generations of advanced attitude control systems, a sensor-based approach using Incremental Backstepping control is developed and proposed in this thesis. Assuming full state availability and fast control action, the resulting time-scale separation between the state of the system and the state of the controller allows to consider an incremental form of the attitude dynamics, where backstepping controllers can be designed to achieve stability and convergence with incremental inputs. This results in integral-control action where information of angular acceleration and actuator output measurements is required. The robustness and the full potential of Incremental Backstepping are evidenced in face of external disturbances, uncertainties, and unknown parameters. External disturbances are well suppressed in contrast with conventional backstepping and Lyapunov-based (non)linear controllers. Furthermore, the attitude stabilization results to be insensitive to parametric uncertainties and robust against model uncertainties. However, this comes at the expense of higher control effort. Moreover, with the influence of model and parametric uncertainties the resulting closed-loop dynamic performance can be better accounted for by studying the convergence and stability properties in terms of Lyapunov theory. This methodology results in a simple, yet effective, family of robust nonlinear attitude controllers which aims to meet demanding requirements in terms of robustness, stability and performance, which in turn, close the gap towards the development of future advanced attitude control systems.Dynamics and Control of Aerospace VehiclesControl and Operations (C&O) - Control and Simulation Division (C&S)Aerospace Engineerin
Overview Of Coupling Of Data, Models And Information Through The Web Using Existing Standards
No full textAssessment of environmental status and integral safety requires combination of information from many sources, coming from either databases or increasingly via live model (scenario) simulations. Many of these models require input from one another, sometimes unidirectional, but more and more two-directional as well. Many protocols and frameworks are available for model coupling, often based on open standards and implementations. Previous overviews of coupling protocols have focused on data exchange volume, data complexity, invasiveness into existing models and support for specific programming languages. We extend the overview using recent developments in web-based protocols and focus on the suitability for internet-based data exchange. We also extend the focus of previous reviews by also taking the coupling with aggregated information products for end-users into account. We propose a hierarchical ordering of all standards for specific types of end-users.Coastal EngineeringEnvironmental Fluid Mechanic
Assessing local and regional economic impacts of climatic extremes and feasibility of adaptation measures in Dutch arable farming systems
Get PDFWe propose a method that combines local productivity factors, economic factors, crop-specific sensitivity to climatic extremes, and future climate change scenarios, to assess potential impacts of extreme weather events on agricultural production systems. Our assessment is spatially explicit and uses discounted time series of cash flows taking into account expected future impacts on yield and crop quality, to estimate changes in the expected net present value (NPV) of agricultural systems. We assess the economic feasibility of a portfolio of adaptation measures by considering their initial investments, annual costs, and effectiveness in reducing crop damage. We apply the method to investigate potential economic impacts of extreme weather events in arable farming systems in the Netherlands around 2050. We find that the expected increase in extreme weather events frequency can severely affect future productivity potential. Particularly, heat waves, warm winters, and high intensity rainfall are expected to substantially undermine the future economic viability of Dutch arable farming systems. The results indicate considerable differences between regions in terms of vulnerability to climatic extremes: while some regions are severely impacted by all climatic extremes, other regions consistently demonstrate high resilience to increases in extreme event frequency. The findings are robust to a wide range of scenarios and suggest that the interactions between economic factors and management practices (particularly, crop specialisation) are decisive drivers of the economic viability of agricultural systems under more frequent climatic extremes. However, the exact magnitude of the impacts remains highly uncertain, as we do not consider endogenous interactions in market conditions resulting from climate change and socio-economic developments. Nevertheless, crop adaptation measures should be regarded as no-regret strategies, since they alleviate both economic impacts and uncertainty around impact magnitude. The proposed method provides insights in region-specific threats and opportunities that are relevant for stakeholders and policy-makers. This information improves communication on main climate risks at the local and regional levels and contributes to prioritising adaptation strategies
