New paper: Agent-based modeling for community resource management: Acequia-based agriculture

We have just got a paper accepted in Computers, Environment and Urban Systems entitled “Agent-based modeling for community resource management: Acequia-based agriculture.” In the paper we explore the complex social interactions of water management, which involves landowners collectively maintaining and managing ditches which distribute water among the properties.

This system of the physical ditches and the maintaining organization together is known as an acequia, and the landowners who maintain it are called Parciantes. Acequias are interesting to researchers because of the developed common property regimes they require to function. The water carried by the ditches is a shared resource, and the complex management system of the acequia has evolved to avoid Hardin’s tragedy of the commons with regard to natural resources in the sense that it prevents the resource from being overused or under-maintained to the detriment of everyone. Ostrom has extensively studied the process of sharing such resources, investigating the structures set in place to preserve them. In ‘‘Governing the Commons’’, her book on common pool resources and human–ecosystem interactions, she suggests a set of characteristics that define stable communal social mechanisms. These characteristics include the presence of environment-appropriate rules governing the use of collective goods and the efficacy of individuals in the system.

Below is the abstract from the paper:

Water management is a major concern across the world. From northern China to the Middle East to Africa to the United States, growing populations can stress local water resources as they demand more water for both direct consumption and agriculture. Irrigation based agriculture draws especially heavily on these resources and usually cannot survive without them; however, irrigation systems must be maintained, a task individual agriculturalists cannot bear alone. We have constructed an agent-based model to investigate the significant interaction and cumulative impact of the physical water system, local social and institutional structures which regulate water use, and the real estate market on the sustainability of traditional farming as a lifestyle in the northern New Mexico area. The regional term for the coupled social organization and physical system of irrigation is ‘‘acequias’’. The results of the model show that depending on the future patterns of weather and government regulations, acequia-based farming may continue at near current rates, shrink significantly but continue to exist, or disappear altogether.
In the figure below we show some of our efforts in verification of the model, specifically, the water network, after 100 years of regular maintenance (A) and after 100 years of no maintenance (B). The darker the line, the more clear the segment is of sedimentation; only unmaintained acequias are impacted by sedimentation in this model, and appear in lighter shades.

Below is a movie are a few sample model runs showing how different scenarios play out, specifically with respect to land-use change.

Full reference:

Wise, S. and Crooks, A. T. (2012), Agent Based Modelling and GIS for Community Resource Management: Acequia-based Agriculture, Computers, Environment and Urban Systems. Doi http://dx.doi.org/10.1016/j.compenvurbsys.2012.08.004.
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A Semester with OpenSim

Over the last few months I have been teaching a class in the Department of Computational Social Science entitled “Building Virtual Worlds” where we surveyed the role of virtual worlds for social science research. The emphasis of the class was on tools, software frameworks, and applications of virtual worlds.  On the applications side we discussed how virtual worlds are being used for History, Archeology, Healthcare, Tourism, Urban Modeling, Architecture, Agent-based Modeling along with more generally teaching and learning. We explored a variety of tools for building virtual worlds before focusing on OpenSim. The movie below shows some of the final outputs using OpenSim.
We used OpenSim 0.7.3, configured with the Standalone-Hypergrid mode and a SQLite database hosted on a Windows 7 server. The server simultaneously simulated 64 different regions, and at various points during the semester the server hosted well over 15000 primitives (prims) and ran hundreds of scripts across this landscape; one region alone hosted over 8000 prims. 
Why so many regions? We were interested in how many the server could cope with but also we wanted to have a virtual world representing the whole of the GMU Fairfax campus  (~4km2) and regions in OpenSim are limited to 256m by 256m. We built the terrain for the campus utilizing the National Elevation Dataset (NED) DEM from the United States Geological Survey which was first manipulated in ArcGIS before being processed in  L3DT (Large 3D Terrain Generator). Finally, the DEM was imported into OpenSim. The movie below should give a sense of what the basic terrain looks like.
Once the terrain was built, we populated it with buildings, however, we were not just interested in the external appearance of the buildings but also there internal structure for modeling and simulation purposes.  Therefore the class focused their attention on building a highly detailed Johnson Center.
Model of Johnson Center taken from Google SketchUp 3D Warehouse
Vector based, 2D CAD files were obtained and imported into Google SketchUp before using SketchLife to build the 3D initial building core, walls, doors and windows.

Constructing a vector-based model of the Johnson Center internal structure
The SketchLife final rendering of the Johnson Center
Once built in SketchUp using SketchLife the model was imported into OpenSim 

External view “in world” of what we accomplished in building the Johnson Center
In addition to using SketchLife for the JC, many objects such as chairs, staircases and tables were either built using the tool or those native to OpenSim.
An “in world” shot at ground level, on the 1st floor, viewing the atrium and clock tower
 in the Johnson Center
CSS class photo “in-world”
However, our work with OpenSim does not stop here, below is another movie of some ongoing work with one of our PhD students, Chris Rouly who is creating agent-based models embedded in OpenSim to explore past habitats among many other things.
I would like to thank the “Building Virtual Worlds” class and the Department for enabling this blog post.

Continue reading »

A Semester with OpenSim

Over the last few months I have been teaching a class in the Department of Computational Social Science entitled “Building Virtual Worlds” where we surveyed the role of virtual worlds for social science research. The emphasis of the class was on tools, software frameworks, and applications of virtual worlds.  On the applications side we discussed how virtual worlds are being used for History, Archeology, Healthcare, Tourism, Urban Modeling, Architecture, Agent-based Modeling along with more generally teaching and learning. We explored a variety of tools for building virtual worlds before focusing on OpenSim. The movie below shows some of the final outputs using OpenSim.
We used OpenSim 0.7.3, configured with the Standalone-Hypergrid mode and a SQLite database hosted on a Windows 7 server. The server simultaneously simulated 64 different regions, and at various points during the semester the server hosted well over 15000 primitives (prims) and ran hundreds of scripts across this landscape; one region alone hosted over 8000 prims. 
Why so many regions? We were interested in how many the server could cope with but also we wanted to have a virtual world representing the whole of the GMU Fairfax campus  (~4km2) and regions in OpenSim are limited to 256m by 256m. We built the terrain for the campus utilizing the National Elevation Dataset (NED) DEM from the United States Geological Survey which was first manipulated in ArcGIS before being processed in  L3DT (Large 3D Terrain Generator). Finally, the DEM was imported into OpenSim. The movie below should give a sense of what the basic terrain looks like.
Once the terrain was built, we populated it with buildings, however, we were not just interested in the external appearance of the buildings but also there internal structure for modeling and simulation purposes.  Therefore the class focused their attention on building a highly detailed Johnson Center.
Model of Johnson Center taken from Google SketchUp 3D Warehouse
Vector based, 2D CAD files were obtained and imported into Google SketchUp before using SketchLife to build the 3D initial building core, walls, doors and windows.

Constructing a vector-based model of the Johnson Center internal structure
The SketchLife final rendering of the Johnson Center
Once built in SketchUp using SketchLife the model was imported into OpenSim 

External view “in world” of what we accomplished in building the Johnson Center
In addition to using SketchLife for the JC, many objects such as chairs, staircases and tables were either built using the tool or those native to OpenSim.
An “in world” shot at ground level, on the 1st floor, viewing the atrium and clock tower
 in the Johnson Center
CSS class photo “in-world”
However, our work with OpenSim does not stop here, below is another movie of some ongoing work with one of our PhD students, Chris Rouly who is creating agent-based models embedded in OpenSim to explore past habitats among many other things.
I would like to thank the “Building Virtual Worlds” class and the Department for enabling this blog post.

Continue reading »

Harvesting ambient geospatial information from social media feeds

A paper I  recently co-authored with Anthony Stefanidis and Jacek Radzikowski from George Mason University entitled “Harvesting ambient geospatial information from social media feeds” is now available in  GeoJournal.   The abstract …

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Harvesting ambient geospatial information from social media feeds

A paper I  recently co-authored with Anthony Stefanidis and Jacek Radzikowski from George Mason University entitled “Harvesting ambient geospatial information from social media feeds” is now available in  GeoJournal.   The abstract …

Continue reading »
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