Abstract

Despite the increasing attention in recent years to the spatial dimensions of economic development, consideration of the importance of space and the recognition that macro, aspatial perspectives can prove to be misleading are not new. Around the world, much of the disappointment with the outcomes from spatial interventions may be traced to a lack of understanding of how regional economies work. This paper reviews the challenges that the consideration of regions brings into economic analysis. This work provides an overview of some of the key methods and tools that can be used to gain a better understanding of how regional economies work. The review aims to guide practitioners and analysts in the use of tools for regional economic analysis and inform discussion of the challenges regions face and the opportunities on which they can build. Document type: Book

Abstract

This chapter raises issues and ideas for exploring resilience, stemming from various research disciplines, projected on the domain of air traffic management and aviation at interconnected system levels. Attempts are made to connect micro, meso, and macro levels in the aviation sector identifying corresponding research challenges. Examples of this ongoing research are given on how theory has already been translated into practical methodological use. Some connections between foci from Resilience Engineering, Disaster Resilience, and other research disciplines are projected on the air traffic management domain to explore how practical benefits can be obtained from these theories and which aspects of operational practice these theories connect to. The chapter shows that the concept of resilience from various research disciplines has a potentially wide application to system levels of air traffic management, and suggests resilience to be addressed from an interconnected systems perspective to provide added value to operations. Document type: Part of book or chapter of book

Abstract

Geosimulation is a form of microsimulation that seeks to understand geographical patterns and dynamics as the outcome of micro level geographical processes. Geosimulation has been applied to understand such diverse systems as lake ecology, traffic congestion and urban growth. A crucial task common to these applications is to express the agreement between model and reality and hence the confidence one can have in the model results. Such evaluation requires a geospatial perspective; it is not sufficient if the micro-level interactions are realistic. Importantly the interactions should be such that the meso and macro level patterns that emerge from the model are realistic. In recent years, a host of map comparison methods have been developed that address different aspects of the agreement between model and reality. This paper places such methods in a framework to systematically assess the breadth and width of model performance. The framework expresses agreement at the continuum of spatial scales ranging from local to the whole landscape and separately addresses agreement in structure and presence. A common reference level makes different performance metrics mutually comparable and guides the interpretation of results. The framework is applied for the evaluation of a constrained cellular automata model of the Netherlands. The case demonstrates that a performance assessment lacking either a multi-criteria and multi-scale perspective or a reference level would result in an unbalanced account and ultimately false conclusions. Document type: Part of book or chapter of book

Abstract

The conflict resolution task performed by air-traffic controllers appears a suitable task for automation using CBR. This is because human competence seems to involve recognising situations and reusing solutions. In this paper we present our experiences in developing a CBR system to support this conflict resolution task. We discuss the problems of case representation: the macro problem of what should constitute a case and the micro problem of how to characterise a case. We evaluate some alternative case representations and identify a representation with one aircraft per case that is extendible to describe conflicts with multiple aircraft. Document type: Part of book or chapter of book

Abstract

While characterizing the mechanical behavior of granular assemblies through DEM simulations, various macro and micro level heterogeneities are often encountered. Such macro level heterogeneities may arise due to stress and void concentration near the wall boundaries; whereas, the micro level heterogeneities are attributed to consideration of only limited number of particles within the representative volume element (RVE). The present study assesses these macro and micro level heterogeneities in reference to the mechanical characterization of sand in DEM-based biaxial test simulation with both rigid and flexible lateral boundaries. In this regard, stresses and strains have been calculated using a wall-based global estimation and a representative area element (RAE)-based local estimation. It has been suggested that the RAE should occupy a maximum of 90% area of the specimen in order to avoid any macro level heterogeneity and can still be able to capture its overall mechanical behavior. For obtaining the spatial variation of field variables, RAE of smaller diameters are often employed. In such cases, depending on the average particle size of the granular assembly and the specimen dimensions, the diameter of the RAE should be selected ensuring that it is small enough to aptly capture the local variation of field variables and at the same time, large enough to avoid any micro level heterogeneity.