2,745 research outputs found
A Novel Method to Structure the World in Population Entities and Application to European Countries and Regions
A novel method is presented to describe population entities. It consists of 2 steps. First the structure of a population entity is described in terms of sub entities using a logarithmic distribution. This allows the uniform description of the World in continents, continents in countries, countries in provinces, provinces in cities, etc. Secondly the logarithmic distribution is simplified. This reveals the main structural differences and similarities at a certain level (countries in terms of provinces for example) and opens a window to study scale effects (comparing the description a province in cities and the world in terms of countries for example). The novel method is applied to the description of the European countries in terms of regions. The results are commented, focussing on the differences and similarities between Southern, Middle and Northern Europe.
Climate research Netherlands : research highlights
In the Netherlands the temperature has risen, on average, by 1.6°C since 1900. Regional climate scenarios for the 21st century developed by the Dutch Royal Meteorological Institute [1] show that temperature in the Netherlands will continue to rise and mild winters and hot summers will become more common. On average winters will become wetter and extreme precipitation amounts will increase. The intensity of extreme rain showers in summer will increase and the sea level will continue to rise. Changing climate will affect all segments and sectors of the society and the economy of the Netherlands, but it also brings new opportunities for major innovation
Long-Term Functionality of Rural Water Services in Developing Countries: A System Dynamics Approach to Understanding the Dynamic Interaction of Causal Factors
Research has shown that sustainability of rural water infrastructure in developing countries is largely affected by the dynamic and systemic interactions of technical, social, financial, institutional, and environmental factors that can lead to premature water system failure. This research employs systems dynamic modeling, which uses feedback mechanisms to understand how these factors interact dynamically to influence long-term rural water system functionality. To do this, the research first identified and aggregated key factors from literature, then asked water sector experts to indicate the polarity and strength between factors through Delphi and cross impact survey questionnaires, and finally used system dynamics modeling to identify and prioritize feedback mechanisms. The resulting model identified 101 feedback mechanisms that were dominated primarily by three and four-factor loops that contained some combination of the factors: Water System Functionality, Community, Financial, Government, Management, and Technology. These feedback mechanisms were then scored and prioritized, with the most dominant feedback mechanism identified as Water System Functionality – Community – Finance – Management. This research offers insight into the dynamic interaction of factors impacting sustainability of rural water infrastructure through the identification of these feedback mechanisms and makes a compelling case for future research to longitudinally investigate the interaction of these factors in various contexts
A flood vulnerability index for coastal cities and its use in assessing climate change impacts
Worldwide, there is a need to enhance our understanding of vulnerability and to develop methodologies and tools to assess vulnerability. One of the most important goals of assessing coastal flood vulnerability, in particular, is to create a readily understandable link between the theoretical concepts of flood vulnerability and the day-to-day decision-making process and to encapsulate this link in an easily accessible tool. This article focuses on developing a Coastal City Flood Vulnerability Index (CCFVI) based on exposure, susceptibility and resilience to coastal flooding. It is applied to nine cities around the world, each with different kinds of exposure. With the aid of this index, it is demonstrated which cities are most vulnerable to coastal flooding with regard to the system's components, that is, hydro-geological, socio-economic and politico-administrative. The index gives a number from 0 to 1, indicating comparatively low or high coastal flood vulnerability, which shows which cities are most in need of further, more detailed investigation for decision-makers. Once its use to compare the vulnerability of a range of cities under current conditions has been demonstrated, it is used to study the impact of climate change on the vulnerability of these cities over a longer timescale. The results show that CCFVI provides a means of obtaining a broad overview of flood vulnerability and the effect of possible adaptation options. This, in turn, will allow for the direction of resources to more in-depth investigation of the most promising strategies
Estimation of Large-Scale Multi-Rate Systems ⋆
model predictive control and estimation of large-scal
On the R-boundedness of stochastic convolution operators
The -boundedness of certain families of vector-valued stochastic
convolution operators with scalar-valued square integrable kernels is the key
ingredient in the recent proof of stochastic maximal -regularity,
, for certain classes of sectorial operators acting on spaces
, . This paper presents a systematic study of
-boundedness of such families. Our main result generalises the
afore-mentioned -boundedness result to a larger class of Banach lattices
and relates it to the -boundedness of an associated class of
deterministic convolution operators. We also establish an intimate relationship
between the -boundedness of these operators and the boundedness of
the -valued maximal function. This analysis leads, quite surprisingly, to an
example showing that -boundedness of stochastic convolution operators fails
in certain UMD Banach lattices with type .Comment: to appear in Positivit
Controlling complex policy problems: a multimethodological approach using system dynamics and network controllability
Notwithstanding the usefulness of system dynamics in analyzing complex policy
problems, policy design is far from straightforward and in many instances
trial-and-error driven. To address this challenge, we propose to combine system
dynamics with network controllability, an emerging field in network science, to
facilitate the detection of effective leverage points in system dynamics models
and thus to support the design of influential policies. We illustrate our
approach by analyzing a classic system dynamics model: the World Dynamics
model. We show that it is enough to control only 53% of the variables to steer
the entire system to an arbitrary final state. We further rank all variables
according to their importance in controlling the system and we validate our
approach by showing that high ranked variables have a significantly larger
impact on the system behavior compared to low ranked variables
Cross-Comparison of Climate Change adaptation Strategies Across Large River Basins in Europe, Africa and Asia
A cross-comparison of climate change adaptation strategies across regions was performed, considering six large river basins as case study areas. Three of the basins, namely the Elbe, Guadiana, and Rhine, are located in Europe, the Nile Equatorial Lakes region and the Orange basin are in Africa, and the Amudarya basin is in Central Asia. The evaluation was based mainly on the opinions of policy makers and water management experts in the river basins. The adaptation strategies were evaluated considering the following issues: expected climate change, expected climate change impacts, drivers for development of adaptation strategy, barriers for adaptation, state of the implementation of a range of water management measures, and status of adaptation strategy implementation. The analysis of responses and cross-comparison were performed with rating the responses where possible. According to the expert opinions, there is an understanding in all six regions that climate change is happening. Different climate change impacts are expected in the basins, whereas decreasing annual water availability, and increasing frequency and intensity of droughts (and to a lesser extent floods) are expected in all of them. According to the responses, the two most important drivers for development of adaptation strategy are: climate-related disasters, and national and international policies. The following most important barriers for adaptation to climate change were identified by responders: spatial and temporal uncertainties in climate projections, lack of adequate financial resources, and lack of horizontal cooperation. The evaluated water resources management measures are on a relatively high level in the Elbe and Rhine basins, followed by the Orange and Guadiana. It is lower in the Amudarya basin, and the lowest in the NEL region, where many measures are only at the planning stage. Regarding the level of adaptation strategy implementation, it can be concluded that the adaptation to climate change has started in all basins, but progresses rather slowl
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