Thursday, December 19, 2013

Agent-based Modeling and Theme Parks

Many of us have been to theme parks and waited in long lines to get on a particular attraction (ride), which to some extent reduces the overall experience of going to a theme park (i.e. no-one really likes waiting). The question is what causes these lines to build up and at what times of the day. Moreover, what can be done to reduce such lines thus increasing the visitors experience? These are perfect questions for an agent-based model to explore.  So while at the Winter Simulation Conference, in Washington DC the other week I happened to listen to a paper entitled "An Agent-Based Simulation Approach to Experience Management in Theme Parks" by a group of researchers from the Living Analytics Research Center (LARC) of the Singapore Management University.

GUI of the Smartphone App
In the paper, the authors explore how an agent-based model can be used to increase peoples experience within a theme park. What was particularly interesting about the paper is how the authors used a smartphone app to collect visitors behaviors while at a particular theme park over the course of a day. They then used this data in an agent-based model to understand how the crowds build up at specific attractions and explore various control polices which could potentially increase the visitors experience (i.e. reduce wait times). More information about the project can be found here and other work (publications) from LARC here.

Full reference to the paper:
Cheng, S.-F., Lin, L., Du, J., Lau, H.C. and Varakantham, P. (2013), 'An Agent-Based Simulation Approach to Experience Management in Theme Parks', in Pasupathy, R., Kim, S.-H., Tolk, A., Hill, R. and Kuhl, M.E. (eds.), Proceedings of the 2013 Winter Simulation Conference, Washington, DC, pp. 1527-1538.


Wednesday, December 11, 2013

Book review: A Framework for Geodesign:

Recently I had the pleasure of reading and reviewing the book entitled "A Framework for Geodesign: Changing Geography by Design" by Carl Steinitz. The full review can be found in Environment and Planning B. However, I thought I would share the review to readers of the blog (with some added images).

"People have designed and changed the geography of their landscapes for thousands of years, for the better or for the worse. But with more pressure being placed on the world’s resources, with increasing numbers of people, the question that we are now faced with is, what are the best sustainable design solutions to mitigate these challenges? For example, urban growth is inevitable given the increasing concentration of people living within in cities, and as a trend is expected to continue into the foreseeable future. The question that designers and planners are therefore faced with is what scenarios would lead to say the least amount of loss in biodiversity. But this is a multi-faceted problem ranging in scale from how do people build there homes, to where should new industry be located, or how should land be conserved etc? These are all questions involving spatial decision-making, and where geographic information systems can play an important role. Over the last forty years, geographic information systems (GIS) have increasingly been used to assist in such complex decisions, from modelling urban growth projections through to assessing the spread of pollution (see Longley et al., 2010 for a extensive list of applications). However, one of the original visions for GIS, which is often overlooked, is that of a tool for design (Goodchild, 2010).

In his book “A Framework for Geodesign: Changing Geography by Design” Karl Steinitz brings his vast experience as a landscape architect and planner to such an issue. For those not familiar to the term geodesign, Steinitz (2012) writes in his preference to the book that it “is an invented word, and a very useful term to describe an activity that is not the territory of any single design profession, geographic science or information technology” (p ix). More generally Steinitz (2012) frames geodesign as “the development and application of design-related processes intended to change the geographical study areas in which they are applied and realised” (p1). Or another way of putting it, the merging of geography and design through computers. This is reiterated later on by a quote from Michael Flaxman were he states “Geodesign is a design and planning method which tightly couples the creation of design proposals with impact simulations informed by geographic contexts, systems thinking, and digital technology” (Flaxman quoted in Steinitz, 2012 p 12).

Moreover, geodesign can be considered both as a verb and as a noun which Steinitz relates to design more generally (see Steinitz, 1995). In the sense as a verb, geodesign is about asking questions and as a noun, geodesign is the content of the answers. In this book Steinitz not only clears up the meaning of geodesign but more importantly provides a comprehensive framework (based on his past work) for thinking about strategies of geodesign, and for organising and operationalizing these meanings.

The book is made up of twelve chapters and split into four parts. The first part is spent on framing geodesign and to set the scene for the remainder of book. For example, chapter 1 notes that for geodesign to be successful, one requires collaboration between the design professions (e.g. architects, planners, urban designers, etc.), geographical sciences (e.g. geographers, ecologists, etc), information technologies and those people living within the communities where geodesign is being applied. This is reiterated throughout the book. Chapter 1 also traces the history of geodesign, and how the advent of computer methods for the acquisition, management and display of digital data can be used to link many participants, thus making design not a solitary activity. Chapter 2 introduces the reader to the context for geodesign in the sense that 1) geography matters and that different societies think differently about their geography, 2) scale maters in the sense of what scale should a geodesign project be applied at (e.g., local, regional or global), and what are the appropriate considerations that need to incorporated at each scale, and finally 3) size matters, if the size of the geographic study area increases, there is a high risk of a harmful impact if one makes a mistake.

Part 2 of the book lays out a framework for geodesign. It is important to note that Steinitz does not call this a methodology for geodesign, as he argues one cannot have a singular methodology as the approaches, principles and methods are applied to projects across a range of geographies, scales and sizes. He therefore introduces a framework as a verb, specifically for asking questions, choosing among many methods and seeking possible answers. In order to develop this framework Steinitz walks the reader through six different questions and types of models common in geodesign projects.

Chapter 3 focuses on components of the framework and the questions one needs to address for a successful geodesign project. These questions broadly range from: 1) How should the study area be described? 2) How does the study area operate? 3) Is the current study area working well? 4) How might the study area be altered? 5) What differences might the changes cause?, and finally, 6) How should the study area be changed? As posed by Steinitz, these questions are not a linear progression, but have several iterative loops and feedbacks both with the geodesign team and the application stakeholders. Moreover, Steinitz argues that such questions should be asked three times during the geodesign study, the first to treat them as why questions (e.g. to understand the geographic study area and the scope of the study). Secondly, the questions are asked in reverse order to identify the how questions (e.g. to define the methods of the study, therefore geodesign becomes a decision rather than data driven process) and finally, the questions are asked in sequential order to address the what, where and when questions as the geodesign study is being implemented. Once these three iterations are complete, there can be three possible decisions, yes, no and maybe. If maybe or no, more feedback is needed between the geodesign team and the stakeholders. These iterations highlight how geodesign is an on-going process of changing geography by design.


Using this framework, Chapter 4 discusses the first iteration of questions, that of scoping the geodesign study. The emphasis of this iteration is ensuring that it is being decision-driven as opposed to data-driven. Moreover, it goes over the six questions in an attempt to identity the intended scope for the study before looking at a feasible methodological plan. Chapter 5, moves onto the second iteration, that of designing the study methodology. Having identified the scope of the study (the why) from the first iteration, the geodesign team must then explore how it will be carried out and what are the evaluation criteria. Chapter 6 discusses the third iteration, that of carrying out the geodesign study. That of the what, where and when questions. Throughout these chapters, Steinitz reiterates the need for stakeholder input and feedback from the geodesign team. Moreover, at the end of chapter 6, Steinitz reiterates that the choices mater. The why questions provide a sense of the scope and objectives of the design application: the problem, the study area and those scales required for operationalizing a successful project.

Part 3 of the book looks at nine case studies in geodesign from around the world. Ranging in temporal scale from days to years, from no financial budget to a large budget, and from a small to large numbers of participants. These case studies helped solidify many of the concepts identified in the preceding chapters. They range from urban growth, to urban change to that of fire management. The case studies focus on specific places and utilize GIS with a variety of different techniques, from anticipatory modelling to that of participatory modelling and rule based models (e.g. cellular automata). They also show the importance of visualisation, as Steinitz (2012) notes “spatial visualisation can significantly influence decision making” (p 168). These examples have details but not depth (however, references are given to the full case study report), but this reiterates the purpose of the book, in the sense it is not a “how to” textbook or listing technologies that enable geodesign. It is a discussion with examples of geodesign. Or to quote from the last page of the book “you cannot copy an example but you can gain experience by joining the collaborative activities of geodesign and changing geography by design” (Steinitz, 2012, p 201). The same goes for the applications, they give a valuable insight into what is possible with geodesign. The book concludes by discussing the future applications for geodesign which range from looking at the implications for research in geodesign, and sketching out a geodesign support system (see Ervin, 2011); and in a sense, one could relate this to other planning support systems (see Brail, 2008), but with a greater emphasis on design.

Overall the book is extremely well written and Steinitz provides a critical and personal account of geodesign, which shows his expertise in the area from his years of teaching and carrying out geodesign work. The use of figures and real world examples really helps support the discussion. But if you are looking for a textbook for “how to” do geodesign, or a list of technologies that enable geodesign, you need to look elsewhere. This is a book the principles and practice of geodesign in a general sense, and which provides a valuable resource for those interested in this topic."

References:
Brail, R.K. (ed.) (2008), Planning Support Systems for Cities and Regions, Lincoln Institute of Land Policy, Cambridge, MA.
Ervin, S. (2011), 'A System for GeoDesign', Proceedings of Digital Landscape Architecture, Anhalt University of Applied Science, Dessau, Germany, pp. 145-154.
Goodchild, M.F. (2010), 'Towards Geodesign: Repurposing Cartography and GIS?.' Cartographic Perspectives, 66(7-22).
Longley, P.A., Goodchild, M.F., Maguire, D.J. and Rhind, D.W. (2010), Geographical Information Systems and Science (3rd Edition), John Wiley & Sons, New York, NY.
Steinitz, C. (1995), 'Design is a Verb; Design is a Noun', Landscape Journal, 14(2): 188-200.
Steinitz, C. (2012), A Framework for Geodesign: Changing Geography by Design, ESRI Press, Redlands. CA.
Full reference to the book:
Review of Steinitz, C. (2012), A Framework for Geodesign: Changing Geography by Design, ESRI Press, Redlands. CA.
Full reference to the review:

Crooks, A.T. (2013), Crooks on Steinitz: A Framework for Geodesign: Changing Geography by Design, Environment and Planning B, 40 (6): 1122-1124.


Tuesday, November 19, 2013

Geosimulation Models - AAG 2014: Call for Papers



GEOSIMULATION MODELS

DESCRIPTION OF THE SESSION(S)
Since the publication of Geosimulation in 2004, the use of Agent-based Modeling (ABM) and Cellular Automata (CA) under the umbrella of Geosimulation models within geographical systems have started to mature as methodologies to explore a wide range of geographical and more broadly social sciences problems facing society. The aim of these sessions is to bring together researchers utilizing geosimulation techniques (and associated methodologies) to discuss topics relating to: theory, technical issues and applications domains of ABM and CA within geographical systems.

Papers will discuss issues relating to:
  • Validation, verification and calibration of Agent-based and CA models
  • Hybrid modeling approaches (e.g. utilizing Spatial Interaction, Microsimulation, etc.)
  • Handling scale and space issues
  • Visualization of agent-based models (along with their outputs)
  • Ways of representing behavior within models of geographical systems
  • Participatory modeling and simulation
  • Applications: Ranging from the micro to macro scale
Please e-mail the abstract and key words with your expression of intent to Andrew Crooks by November 28th, 2013. Please make sure that your abstract conforms to the AAG guidelines in relation to title, word limit and key words and as specified at http://www.aag.org/cs/annualmeeting/call_for_papers;. An abstract should be no more than 250 words that describes the presentation's purpose, methods, and conclusions as well as to include keywords. Full submissions will be given priority over submissions with just a paper title.

ORGANIZERS:
Andrew Crooks, Computational Social Science, George Mason University.
Suzana Dragicevic, Department of Geography, Simon Fraser University.
Paul Torrens, Department of Geographical Sciences and Institute for Advanced Computer Studies, University of Maryland.

TIMELINE:
November 19th, 2013: Second call for papers


November 28th, 2013: Abstract submission and expression of intent to session organizers. E-mail Andrew Crooks by this date if you are interested in being in this session. Please submit an abstract and key words with your expression of intent. Full submissions will be given priority over submissions with just a paper title.

November 29th, 2013: Session finalization. Session organizers determine session order and content and notify authors.

December 2st, 2013: Final abstract submission to AAG, via www.aag.org. All participants must register individually via this site. Upon registration you will be given a participant number (PIN). Send the PIN and a copy of your final abstract to Andrew Crooks. Neither the organizers nor the AAG will edit the abstracts.

December 3rd, 2013: AAG registration deadline. Sessions submitted to AAG for approval.

April 8th -12th, 2014: AAG meeting, Tampa Bay, Florida, USA.

Monday, November 04, 2013

The New Science of Cities

Readers of this blog may be interested in Michael Batty's new book "The New Science of Cities" which has just been published  by MIT Press. To quote from the publisher:
"Michael Batty suggests that to understand cities we must view them not simply as places in space but as systems of networks and flows. To understand space, he argues, we must understand flows, and to understand flows, we must understand networks—the relations between objects that comprise the system of the city. Drawing on the complexity sciences, social physics, urban economics, transportation theory, regional science, and urban geography, and building on his own previous work, Batty introduces theories and methods that reveal the deep structure of how cities function."

There is a detailed description of the books content on  Mike's web site www.complexcity.info. The website also hosts numerous papers and books that Mike has written over his many years as a leading urban modeler in all its shapes and forms.



Tuesday, October 22, 2013

New Paper: Measuring Slum Severity in Mumbai and Kolkata

In a move to understand slums, we have switch gears slightly from agent-based modeling to a more statistical study of slums.  To this end we have just received word that our paper entitled "Measuring Slum Severity in Mumbai and Kolkata: A Household-based Approach" has just been Habitat International. Specifically we propose a new household level enumeration of slums and develop a Slum Severity Index as shown Table 4 below. Moreover, the paper estimates number of slum households in Mumbai and Kolkata as shown in Figure 1 (below). Furthermore, the paper demonstrates that varying slum definitions result into stark differences in slum population estimates. Paper abstract:
"Slums pose a significant challenge for urban planning and policy as they provide shelter to a third of urban residents. UN-Habitat reports that, in 2001, approximately 924 million people lived in slums or informal settlements across the world (UN-Habitat, 2003). However, varying definitions of what constitutes a slum result in different slum population estimates. Most definitions treat a slum as a community of several households, rarely recognizing that housing conditions differ for each individual household within the area. Moreover, definitions of slums usually take a dichotomous approach whereby a place is either a slum or not. Little attempt is made to go beyond this slum/non-slum dichotomy. This paper moves beyond the traditional ways of defining a slum by proposing a new household level enumeration of slums and developing Slum Severity Index (SSI), which measures the level of deprivation on a continuous scale based on the UN-Habitat's slum definition. We apply this new approach of analyzing slums to a household survey dataset to estimate the total number of slum households in Mumbai and Kolkata, two megacities in India. To contrast our approach, we compare these estimates with the Census of India's. The comparison highlights stark differences in the two estimates and the slum/non-slum household classifications. The estimates by the Census are considerably smaller than those based on the UN-Habitat definition in both cities. By applying the SSI, we also demonstrate intra-urban variability in housing conditions within our study cities. The analysis highlights differences in slum profiles measured in terms of both housing deprivation levels and housing deprivation types in both cities. The main objective of this study is to demonstrate the usefulness of the household level analysis of slums in drawing implications for designing and implementing slum policies."
Keywords: Slums, Definition, Deprivation, India, Housing.


Full Reference: 
Patel, A., Koizumi, N. and Crooks, A.T. (2014), Measuring Slum Severity in Mumbai and Kolkata: A Household-based Approach, Habitat International, 41: 300-306. (pdf)
If you would like to read the paper and don't have access to Habitat International, feel free to send us an email and we can send you an early version of the paper.