Comital Ireland, 1333–1534

The history of late-medieval Ireland is not exactly littered with dates that command general recognition, so it is surely suggestive that two which have achieved a degree of notoriety concern the fortunes, or rather misfortunes, of Ireland’s earls and earldoms: the murder of William Burgh, the ‘brown’ earl of Ulster, in 1333; and the rebellion in 1534 of Thomas Fitzgerald (‘Silken Thomas’), soon-to-be tenth earl of Kildare. These are dates of demarcation. In the broadest terms, 1333 has been understood to mark the end of the expansion of royal power under the Plantagenets, 1534 the start of its vigorous reassertion under the Tudors. What occurred between these chronological bookends? For Goddard Orpen (d. 1932), writing in 1920 when the Anglo-Irish tradition he cherished seemed imperilled by the prospect of Irish secession from the United Kingdom, the murder of the earl of Ulster in 1333 was a moment of dark, almost metonymic, significance: ‘the door was now closed on a century and a half of remarkable progress, vigour, and comparative order, and two centuries of retrogression, stagnation, and comparative anarchy were about to be ushered in’

The Torus-Equivariant Cohomology of Nilpotent Orbits

We consider aspects of the geometry and topology of nilpotent orbits in finite-dimensional complex simple Lie algebras. In particular, we give the equivariant cohomologies of the regular and minimal nilpotent orbits with respect to the action of a maximal compact torus of the overall group in question.Comment: 17 pages. Comments are most welcome. Version 2: A few minor changes were mad

Exploring Cities Using Agent-Based Models and GIS

Cities are faced with many problems such as urban sprawl, congestion, and segregation. They are also constantly changing. Computer modelling is becoming an increasingly important tool when examining how cities operate. Agent based models (ABM) allow for the testing of different hypotheses and theories for urban change, thus leading to a greater understanding of how cities work. This paper presents how ABMs can be developed by their integration with Geographical Information System (GIS). To highlight this, a generic ABM is presented. This is then applied to two model applications: a segregation model and a location model. Both models highlight how different theories can be incorporated into the generic model and demonstrate the importance of space in the modelling process. Cities are faced with many problems such as urban sprawl, congestion, and segregation. They are also constantly changing. Computer modelling is becoming an increasingly important tool when examining how cities operate. Agent based models (ABM) allow for the testing of different hypotheses and theories for urban change, thus leading to a greater understanding of how cities work. This paper presents how ABMs can be developed by their integration with Geographical Information System (GIS). To highlight this, a generic ABM is presented. This is then applied to two model applications: a segregation model and a location model. Both models highlight how different theories can be incorporated into the generic model and demonstrate the importance of space in the modelling process

The Repast Simulation/Modelling System for Geospatial Simulation

The use of simulation/modelling systems can simplify the implementation of agent-based models. Repast is one of the few simulation/modelling software systems that supports the integration of geospatial data especially that of vector-based geometries. This paper provides details about Repast specifically an overview, including its different development languages available to develop agent-based models. Before describing Repast’s core functionality and how models can be developed within it, specific emphasis will be placed on its ability to represent dynamics and incorporate geographical information. Once these elements of the system have been covered, a diverse list of Agent-Based Modelling (ABM) applications using Repast will be presented with particular emphasis on spatial applications utilizing Repast, in particular, those that utilize geospatial data