Archive for the ‘geographic information systems’ Category

Activities reveal features and their attributes

Thursday, February 2nd, 2012

I believe an approach that is based on Gibson’s idea of affordances is already off to a good start because it places human experiences, namely activities/tasks, as priority. Theoretically, it offers us an opportunity to escape from the daunting task of defining the precise boundaries of a river or the exact place a mountain ends as objects of reality and focus on how features allow activities to be performed. However, more importantly, I think it fits in nicely with Heidegger’s idea that nature is fundamentally revealing. According to him, there are two ways of things come into being, either through “phusis”, where a thing rises from itself and retrieves back into itself (flower blossoming) or through “techne”, where a craftsmen brings a thing comes into being (carpenter makes a bench out of wood). In short, a feature in the world reveals a certain part of itself to us depending on the task we seek to accomplish.

I think the paper could have been improved if the authors first give an overview of existing methods of ontology construction,, whether object-oriented or field-oriented, and discuss their advantages/disadvantages. In particular, which aspects are poorly served by constructing a GIS ontology through an object-oriented approach and how does the approach based in affordances address these issues. This comparison would have helped to demonstrate the strengths of their method more clearly. One questions arose while thinking about ontologies that supported activities. If an activity-oriented ontology is based on certain activities, I wonder then, if an ontology can be constructed for a map designed for general purposes like Google Map or Google Earth?
– Ally_Nash

Problem Solvers, Critical Theorists and the Inuit

Thursday, February 2nd, 2012

I think that Smith and Kuhn have different viewpoints of ontology. While Smith takes a “problem solving” approach, Kuhn approaches it with a more “critical theory” approach. That is, that Smith accepts the structure of the system and works within in it, while Kuhn attempts at a complete restructure. I personally found the Kuhn article a little more difficult to process, but I did find it interesting that he focuses on language and logic theory. I also noted that while Kuhn suggests that there are “Ontology designers” who appoint what may be included in GIS language and or experience. Contrary to this, Smith infers that our ontologies are subconscious and are created through our personal life experiences. He mentions (as other classmates have cited) that someone who is exposed to plains and fields might have a different impression of a mountain range.

ClimateNYC also mentions this, and I will add that not only would an Inuk have difficulty describing a desert, but it has been noted by many anthropologists that Inuit have an extended vocabulary for certain types of snow and ice. Professor Colin Scott (McGill) suggests they might have four, five or six separate words describing snow; all dependant on the temperature and moisture content etc.  This concept is foreign to even Canadians. I personally can only think of two; wet snow (slush) and normal snow (these days snow is almost non-existent and ice may soon replace the word snow).

Both authors take interesting standpoints. Personally, I like Smith’s perspective. I believe that Ontologies occur without conscious effort. They are formed through many years and experiences, each one contributing to a personal ontology of a thing or concept. I’m not sure that it is entirely correct to categorize and engineer a proper set of rules and defined ontologies.

Andrew “GIS” Funa

*I would prefer to not use the term Eskimo as it has been tied to certain negative connotations (that in itself may been ontological)

*I also will add that ClimateNYC infers that Inuit do not live in the desert, but just to be picky, I will add that they more often than not, do in fact live in a desert per se.

 

An ontology based on relational thinking

Thursday, February 2nd, 2012

After reading the paper, I am still not very confused as to what the authors were arguing for. The different sub-headings seem independent from each other, which made their train of thought hard to follow. Often, I would find myself asking, “so how does that say about building an ontology of landforms?”

Before building such ontology, we as humans must first come to a clear understanding/philosophy of our relationship with our environment and the Earth. Although I am not sure if these terms can be equated, to me, primary theory sounds a lot like objectivism where things are deemed to exist upon being perceived and secondary theory sounds a lot of subjectivism where what exists depends on cultural believes and discourse. This dualistic way of understanding our relationship to nature is problematic. We cannot interpret our environment/space/geography as something that is external and separate from us when it is the very thing that allows us to experience ourselves. The French philosopher Merleau-Ponty has dedicated his life to constructing the Gestalt ontology. Naess has also extended this ontology in environmental philosophy. For me, the Gestalt ontology is the right direction we should be heading because it tries to marry the subjective-objective/mind-body duality in a way that the two views can remain distinct while remaining the same thing.

A gestalt “refers to a network of relationships whose various elements are mutually defining” (Diehm, 25). Gestalt is thus the smallest meaning chunk that we derive sense from. A good way to think about gestalt is by referring to a sculpture of a man holding a woman by Auguste Rodin. In one instance, the sculpture is called “Fugit Amor” and expresses the emotions of love, longing, and desire. In the second instance, the same sculpture appears on the door of “Dante’s Inferno” and expresses suffering and agony. Depending on the context and the meaning of the elements are changed completely.

I think an ontology of landforms should somehow encompass this way of relational thinking. Also, experience should be given the utmost importance because it is how we “know” the world and through it, how the world experiences itself (this is also way I like the idea of affordances). I would like to argue that the mountain does NOT exist before humans came along in the same way that it exists today after we have experience it because before experience a so called mountain is completely meaningless.

Diehm, C. (2006). Arne Naess and the Task of Gestalt Ontology. Environmental Ethics, 28(21-35). Retrieved on February 1st, 2012 from www.umweltethik.at/download.php?id=439

-Ally_Nash

 

Inclusive Ontologies

Thursday, February 2nd, 2012

In my last post, I questioned the need for developing a complete geographic ontology, as it perhaps marginalizes certain ways of knowing. Werner Kuhn—by illustrating how GIS can better support human activities through the use of ontologies, which specify and produce to user needs—has clarified many of my questions and concerns. For example, Kuhn forms a much stronger relationship between the inefficiencies of trying to access and use the many geographic datasets (of varying ontologies) with giving priority to human activities and encouraging efficient use.

One of the elements that I found to be interesting was how the relationship between the ontology designers and the subjects was highlighted. Designers and those who engage in field work are actively choosing what to include in their projects; they are not passive recorders, but instead engage with and impact their fields of work. I would like to note that while these decisions are explicit, choices are also being made at a sub-conscious level.

Khun suggests that a GIS’s purpose should guide how its language is determined. Because humans’ perception of the world is based off of the objects as well as actions, ontologies need to incorporate both. In the portage example, an ontology would not only include how a community perceives a path to be a part of body of water, but also how it uses it, thereby placing significant importance on the requirements of the community. By hierarchically structuring activities and objects (while paying very close attention to semantics), it had become clear to me now the way in which ontologies have the capability to include the varying perceptions of people’s environment while also enabling greater interoperability, which will increase efficiency and usability.

– jeremy

Ontologies, Ontologies… Ontologies Everywhere

Thursday, February 2nd, 2012

Smith and Mark posit that in order to address the incompatibilities that arise when data gatherers use varying terms and concepts, a complete geographic ontology needs to be developed. But this is a daunting task, as through engaging with the world, every person  develops a specific conceptualization of their environment. This conceptualization varies between members within a community (with regards to both primary and secondary theories), and often varies drastically between members of different communities. I would like to ask if the process of creating a complete ontology—as it seeks to facilitate understanding—in fact marginalizes certain ways of knowing.

As noted by Madskiier_JWong, the portage path example confronts our understanding of primary theory in that it is an ontology that is not ‘common sense’ to most of us. This way of perceiving the world, like Smith and Mark illustrate, is influenced by how the environment is being used. I have difficulty, however, in envisioning how this specific way of perceiving bodies of water could be incorporated into a universal geographic ontology. Could it be its own ontology portage ‘layer’ that can be combined with other perceptions of waterbodies? Or would it be incorporated into a larger set and adjusted to fit a norm?

In addition, Smith and Mark illustrate how the primary theories of certain geographical features may be underdeveloped for various communities. Mountains, for example, may be a fuzzy concept for those living on isolated flatlands. But to be beneficial to those living on isolated flatlands, does a geographic ontology need to include how others perceive mountains? In a human geography sense, it is arguable that the goal of creating a geographic ontology is so that it can be tailored and be of benefit to those it is being designed for. By going back to the portage example, it can be said that the concept of these paths being a part of waterbodies is in fact a geographic social construct (which may not be translatable to other communities) but representing this in contrast to other ways of imagining waterbodies is arguably its strength.

As for who a complete geographic ontology would be useful for, Mark and Smith note several examples in their conclusion: pilots, soldiers, scientists, hikers, firefighters, and naturalists. It is clear that creating a unified geographic language would be of benefit to these individuals, but this seems to be a top-down approach. In creating a geographic ontology, perhaps the focus should be on specifically tailoring it for the needs and values of the community at hand in order to understand and serve it—non-intertranslatables and all.

– jeremy

Cultural differences in affordances?

Thursday, February 2nd, 2012

Combining thoughts of secondary theory as put forth by Smith and Mark and the topic of affordances put forth by Kuhn offers a complex evaluation of how different cultures use different objects. Kuhn quotes Gibson: “the affordances of the environment are what it offers the animal,” (617), which I follow with the assumption that environments may offer different “animals” different things, and spur various forms of activity.

In the beginning of his paper Kuhn poses the question, “what can be done to make geographical information more supportive of human activities?” (613). The process of creating ontologies includes grasping the actions from a text, then identifying the objects which afford them. I am curious to how much rigour is ensured during this process, and how much of the object-affordance relationship is left to assumption or distant inference. Kuhn notes that the “details of this procedure are also language-dependent” (622), insisting that some statements may be lost in translation. It is difficult for a person to try and examine the activities afforded to certain cultures by certain objects—since, as we know with knowledge of secondary theory, is not consistent across the globe.

Kuhn, Werner. “Ontologies in Support of Activities in Geographical Space.” International Journal of Geographical Information Science. 15.7 (2001): 613-631.

-sidewalk ballet

Ontologies and GIS, in context

Thursday, February 2nd, 2012

Kuhn’s article Ontologies in support of activities in geographical space was quite thought provoking for me.  As an overview of ontologies, where they are and where the author believes they could be, it was informative.  At the end of Kuhn’s piece, I found myself wondering two things.  First, I pondered the usefulness of ontologies–genuinely wondering how they are applied.  Iit would have been an interesting addition to their case study of an ontology of German traffic codes if they had also included the usefulness and applicability of where and how this could be used.  Particularly as this article emphasized the necessity of ontologies related to the task at hand, a knowledge of what the “task at hand” could be for such an ontology would have been a thorough and convincing conclusion.

More than that, though, it caused me to reflect on GIS as a whole, and the frustration that comes along with a software (tool/science/system?) that has the ability to include immense amounts of data and answer many questions.  As mentioned, Kuhn posits that “the tasks (or activities) to be supported by a GIS should determine the entities that are admitted to its languages”.  When using GIS as a tool, this is a mentality that should not be forgotten.  The task at hand is incredibly important.  GIS can accomplish many things, analyze interesting data, find solutions and, sometimes, create more problems.  As a user with a plethora of tools before you, it can be intimidating, or you may attempt to do too much.  With the geospatial and human world being incredibly vast and comprehensive, it seems like it should go without saying that decisions made, and tools–or in this case, languages–chosen should be inherent upon the context within which one is working.

sah

Kuhn, Werner. “Ontologies in Support of Activities in Geographical Space.” International Journal of Geographical Information Science. 15.7 (2001): 613-631. Print.

Objectivity and Subjectivity in GIScience

Thursday, February 2nd, 2012

Over the last few weeks I have been considering how GIS can accurately reflect environments across different cultures, and I would like to continue to draw upon the distinctions Smith and Mark make between primary and secondary theory. I argue that primary theory is primarily objective whereas secondary theory is subjective, and consider these implications as they are situated in GIScience.

Smith and Mark detail that there is a “high degree of correspondence between primary-theoretical beliefs and the reality towards which they are directed,” (7) building on their claim that primary theory isn’t culturally dependent. Objects in primary theory are perceived pretty accurately; Smith and Mark state they have to be in order for us to live with and among them. For me, this seems easy to incorporate into a GIS that can be used across cultures, despite the fact that (and as noted by ClimateNYC) some cultures may not know what a mountain is after living in Kansas plains for their entire lives. This doesn’t matter though, because primary theory is “tailored to the… characteristic of the human species and… has formed the main support of human life” (7). This is to say that despite one culture lacking an awareness or theory about mountains, for example, it can still be displayed in a GIS because another culture has an established theory, and it is argued that “each primary theory is a theory about what actually exists in reality” (11).

This isn’t so clear with secondary theory where there are “startling differences [in phenomena perception]… as one moves from community to community” (7). GIS attempts to have geographic concepts which are consistent with the user’s mental model of the concepts of the world. How can we do this when users’ mental models vary greatly across cultures? I struggle to see how both the “mechanistic view of the world” held by Westerners and the “spiritualistic world-view” (7) of African communities can be held simultaneously in a program. This can further be applied to natural languages and semantics in GIS—these are not uniform across all cultures and users. How can programs be established that capture the nuances in different languages, in different perceptions of the environment? Further explorations of spatial cognition may provide good avenues for development of this idea.

Smith, B, and D M. Mark. “Do Mountains Exist? Towards an Ontology of Landforms.” Environment and Planning. B, Planning & Design. 30 (2003): 411-428.

-sidewalk ballet

 

What ARE mountains? And why do we care?

Thursday, February 2nd, 2012

An ontology of landforms is an interesting concept.  And this paper approached it in an interesting way, asking, “Do mountains exist?” moving from the various attributes of a mountain into the broader question of how might we characterize our landforms in general.  But I found Smith and Mark addressed multiple ideas without neatly pulling together their main argument and limitations to such an argument.  I was slightly confused as to precisely how they felt about some of their main points—can Primary Theory provide sufficient understanding to create a shared language for landforms, for example?

Upon reading this paper, I was not convinced.  I believe to create one ontology for landforms would be incredibly difficult, even if we are assuming the ontology would be used by a relatively homogeneous group of people (in terms of cultural belief systems/research parameters/etc).  I understand the necessity, as they state, of having a shared language for people such as researchers, pilots, soldiers, scientists, to name a few.  But how can we presume that all people will have the same needs of a landscape, and thus will benefit from the same ontology?  It begs the question “What ARE mountains… and why do we care?”  Well, we care because of the question we are asking—they are relevant to something of interest to us.  As Kuhn states in Ontologies in support of activities in geographical space, ontologies appear to be somewhat task specific.  And the way we define our landscapes is surely specific to how we will be using them?

It seems what they describe as “Primary Theory”, as I understood it, may not relate to understandings that are as general across the board as they necessarily make them out to be.  Perhaps a better knowledge of ontologies on the part of the reader (ie. myself) may have clarified aspects of this argument, or perhaps it is the argument itself.  But it is particularly ironic, in my mind, that in a paper discussing the benefits of a shared and commonly understood language, their ability to express and defend their position was lacking.

sah

Smith, B, and D M. Mark. “Do Mountains Exist? Towards an Ontology of Landforms.” Environment and Planning. B, Planning & Design. 30 (2003): 411-428. Print.

Kuhn, Werner. “Ontologies in Support of Activities in Geographical Space.” International Journal of Geographical Information Science. 15.7 (2001): 613-631. Print.

Kuhn reading and developing a new Ontology

Wednesday, February 1st, 2012

Kuhn’s article is critical of existing ontologies as overly focussing on objects and their attributes. He details the development of a new ontology that embraces processes and actions in addition to objects. He advocates for the formalization of such a system to better represent the geo-spatial component of phenomena. As an example, he uses a German traffic code as a case study to demonstrate innovations in ontology structure.

A contentious point in this article was Kuhn’s assertion that teaching the programming, engineering, and ontology-generating tools to domain experts is useless because these tools are incompatible with the theories. I believe that familiarizing and engaging domain scientists in critical review of these tools (much like what this seminar class is doing) exposes the built-in assumptions and limitations of the ontology; an ontology that originates from computer science and information systems. Furthermore, contemporary neo-geographers and the geospatial web are blurring the distinction between geographers and programmers. Intuitive tools such as search engines and even programming languages that increasingly approximate natural language are emerging.

There is merit in Kuhn’s call for a shift of structuring data to better represent the geographic component of geographical data. However, I believe that it is entirely too abstract to create a new system from scratch. Much like how our understandings of things change over time, is it not possible to allow our ontologies to change organically and incrementally? Such a transition would allow for more recycling of collected data, more exchanges of dialogue, and is probably more feasible.  

– Madskiier_JWong

The Recipe for A Problem-Solving Ontology

Wednesday, February 1st, 2012

Rather than taking an approach that questions the very nature of existence of certain human-created objects, Werner Kuhn’s article instead reads like an instruction manual for how to derive ontologies. Of particular use, he breaks down the actual phenomenon that need to be categorized into four useful bites that allow one to derive an ontology. First, one must create different types of objects; second, classes for these types to belong to; third, functions that each type might perform (an attribute); and, finally, algebraic axioms that define what exactly the actions are that a given type of object affords (618). Of course, the difficult part comes from actually trying to map out the linkages between all of these different types in a domain, then ordering them into a hierarchy which eventually should have “complete executable specifications in a functional language of activities and object classes” (628).

Having completed all this, however, one might wonder what the utility of engineering an ontology might be. The author, of course, provide us with an example of the German traffic rules as one example for understanding how setting up a hierarchical ontology might be useful. He arrives at this example because he believes “ontologies should be designed with a focus on human activities in geographical space” (614). This supposition is further supported by an argument that an accurate ontology should support human activity in space. The act of supporting works because an ontology can “capture knowledge about problem solving in the world” (616). While Werner’s interest lies only in knowledge about the world (616) rather solving problems, we might be able to extrapolate how developing an ontology for traffic rules might aid traffic authorities in constructing further rules or a system for adjudication in Germany.

In thinking about this approach to a problem-solving given what we’ve discussed in class so far, Werner’s recipe for how to construct an ontology appears to be closely akin to Agent Based Modeling. In effect, he believes in taking “types” which could, in some cases, be “agents,” and then figuring out their actions and the hierarchy of how these actions relate to each other. However, his method for constructing an ontology places no emphasis on the individual roles of agents (or types) as does ABM, but instead is more interested in each “type” for its own sake – and for where it sits in a network. In some ways, this reminds me more of a network analysis. Yet I can see how this approach lends itself to something like computer programming that already derives from and creates its own ontologies, and could be greatly aided by engineering a specific existence.
–ClimateNYC

What About the Eskimo?

Wednesday, February 1st, 2012

Barry Smith and David Mark provide an interesting article that gets at the ontology of geographic features in space, but we should carefully heed the authors discussion of how the definitions of geographic features vary from community to community. As “Madskiier” points out, the authors draw a distinction between primary theory (or a basic common-sense perception) of objects versus a secondary theory (that reflects diverse beliefs) that allows for processing of ideas like continuous fields.

It’s in discussing ideas like continuous fields that the authors make clear how little weight certain geographic terms have when looking at tangible reality. For example, continuous fields thought of only in terms of Western contour maps may not exist for cultures who don’t possess such a map-making tradition. Take another idea proposed by Smith and Mark: did Mt. Everest exist before the first human laid eyes upon it? Mt. Everest, itself a blob of elevation, the authors might say, existed long before maps. But the concept of Mt. Everest as a delineated object, perhaps, began existing only when it was drawn on a map. Yet the fact that primary theory allows mountains to be map-created “objects whose boundaries are marked by gradedness or vagueness” (13) doesn’t make mountains a reality. In fact, for those who haven’t seen Mt. Everest (or cultures, people or places for whom real, tangible “mountains do not exist” (13) ) it might be difficult to understand a map portraying one. Confused?

Consider the author’s discussion of geomorphology’s role as a science in studying landforms as supposed “natural” objects (17). Given the fact that landforms are not objects with discrete boundaries except insofar as humans define them, they do not exist except as a concept. By suggestion, the authors question whether or not geomorphology can truly be considered a science. Still confused?

Let’s try examining what I consider the main thesis of the author’s ontological arguments. Smith and Mark posit that many geographic features exist only insofar as human communities have “projected [] speech practices onto the surface of the Earth in such a way that they mark out certain territory with a certain shape and material constitution” (14). In effect, most of the geographic constructs we learn as children such as river, hill, valley, mountain – as the author points out – are simply human constructs of given features which we make into an object. As the authors note, “our common-sense beliefs are readily translated from one language to another, and judgements expressing such beliefs are marked by a widespread unforced agreement” (8). By learning certain concepts as babes, we are reinforcing them as reality (one might argue, perceptual reality), according to the authors.

So, does a mountain actually exist? Sure, insomuch as the term mountain describes what “actually exists in reality — or more precisely in some part of reality that is relevant to human perception and action” (11). Of course, this then begets the question of what is a mountain exactly to someone who has always lived on the flat plains of Kansas and never seen one firsthand? Or, better yet, could an Eskimo describe the category/object of landforms known as a desert after a lifetime living amongst snow and ice?

In this sense, Smith and Mark’s article stems from a long-line of critical theory first suggested by the French philosopher Jacques Derrida who originated the ideas of deconstructionism. Instead of asking about mountains, Derrida might have questioned whether the word “tree” means the same thing to a man from a dense, tropical jungle as a man from the Northern boreal forests of Canada. Since both men could correctly picture a tree but arrive at startlingly different objects, what does this say about the nature of the tree as an object? Or, in Mark and Smith’s terms, of less-defined objects such as mountains?
–ClimateNYC

Smith & Mark and Central Ontologies

Wednesday, February 1st, 2012

Smith and Mark’s article walks the reader from a general, philosophical perspective of ontologies to how geography and finally information systems interpret and utilize ontology. They distinguish between a basic, naïve conceptualization (primary theory) that is akin to common sense and a secondary conceptualization (secondary theory) that is diverse and reflects different beliefs. They argue that geographic science’s ontology is based on discrete objects (primary theory) and continuous fields (secondary theory).

Aside from minor quibbles about the reading’s denseness at the beginning, I found interesting the assertion that humans tend towards a central, binding ontology to better relate things to one another. It has certainly been the case for GIS where there are a few overarching data models (e.g. vector and raster) and clear hierarchical rules of inheritance. Evidence of this central ontology self-perpetuating is evident in the way users now attempt to sort webscraped information or to store streamed data. The titles may vary from producer to producer, but the fundamental logical structure of row ID, one entry per cell, and attributes remains.

A pressing implication of this resides in development, where GIS practitioners attempt to create maps showing traditional ecological knowledge (TEK) that represent a participatory effort with locals. An obstacle seems to exist of trying to translate (for example) Canadian Aboriginal ontologies with the GIS data models in use. The difficulty of labelling a portage path as discussed in class is one such example. I have the impression that the prevailing approach is to undergo acculturation of Aboriginal peoples until they think like “our” Western views. This likely reflects a power relation of Westerners wielding the GIS, and may limit acceptance of alternative forms of knowing.

– Madskiier_JWong

ABMs: representation, coherence, balance

Monday, January 30th, 2012

O’Sullivan’s article is a rather critical account of ABMs. The article states the issue of highly funded models, which are too sensitive to reveal the outcomes of or are too complex to be explained in journal articles (544). State-of-the-art findings will reach a specific audience, not the audience that they were intended for. Thus, if ABMs are social agents, representing social issues, we have one serious limitation. How will transparency, availability, and clarity be attained? Perhaps we should strive for balance in models between the relationship of agents with space, and how and where those agents are represented (545).

I found it difficult not to get lost in the definitions of ABMs. In particular, their accuracy, validity, and lucidity. Bonabeau differentiates ABMs from market models with advancing game theory, by taking the focus off of the ‘theory’ part. On the other hand, O’Sullivan finds ABMs to be simple and abstract, effective for researching theory implications. He goes on further to state that ABMs, as they stand, “cannot establish the truth of those theories” (546). How then, can the truth of those theories be established? Should we be concerned with the idea of theory? Or restructuring what we deem that a model is all together? The issues with regards to the way space and time are represented are being explored and that’s definitely a good thing. Despite all the setbacks, there is much potential in ABMs as they are exploring numerous fields. As long as limitations diminish, there is hope.

-henry miller

ABMs and MBMs

Monday, January 30th, 2012

The focus on Bonabeau’s article here is of agent-based models (ABMs) and market-based models (MBMs). A main difference between an ABM and an MBM is that the former focuses on individual behaviour while the latter deals with collective behaviour. Furthermore, ABMs are driven by the bottom-up approach (focus is placed on the individuals), in contrast to the top-down approach (focus is on the collective) of the classic MBMs.

“ABM captures that emergent phenomenon in a natural way” (7282). Is this much different than a general equilibrium MBM? The MBMs that are largely based on the neo-classical economics are founded on similar ideals of natural systems, such as laissez-faire economics and Adam Smith’s infamous ‘invisible hand’. Referring to another model, Bonabeau states that “each agent acts individually but has perfect knowledge of how many users there are in the population” (7287). Whenever ‘perfect’ is utilized, it reminds me of the classical economic market systems where perfect competition, perfect information, and full employment are all assumptions made in assessing a market scenario with a standard economic model.

Bonabeau is at times too eager and possibly even blinded by his excitement of his tool: “ABM is perfect not just for operational risk in financial institution but for modeling risk in general” (7285). It is problematic to be this certain about a tool that is not fully understood, which he actually takes note of: if ABM is introduced in the market and is unsuccessful, potentially harming individuals with the predictions, or rather understanding (as the article emphasizes) of a situation, then the overestimated tool may do more damage than good. However, the article does mention this, but does not go into detail explaining why “agents behave in a way that is still poorly understood” (7284). Perhaps the statement “AMBs are more of a mindset than a technology” (7280)alludes to this problem. Can we change the modern market system with ABMs if we are aware of their positive and negative implications? Is it possible to create economic software agents that do not simply explain human economic behaviour?

-henry miller

ABMs are hard!

Monday, January 30th, 2012

Bonabeau (2002) articulates the common danger of “improper use of ABM” (7280), regarding the simple technique in ABM creation coupled with the need for conceptual rigour. I don’t think he really explains himself on what he means by “conceptually deep” (7280) throughout the article, and I can see two ways for it to be taken.

With the attempted replication of agent interactions it can be assumed that lots of data is required for the model to be held as valid. Putting value on heterogeneity, individual data can be associated to agents, and there can be multiple different agents in the model doing different things. As agents can exhibit “learning and adaptation” (7281), this needs to be incorporated into the model along with agent rationality and some knowledge of the environment, or adherences to spatial parameters. Modellers are attempting to simulate real occurrences, and we know that human behaviour is incredibly difficult to predict and account for.

Another way I see models as being conceptually deep is in the analysis stage, post-programming. Bonabeau queries “what constitutes an explanation of an observed social phenomenon?” (7281). ABMs capture emergent phenomena, but taking the step to explain this emergent phenomena may prove more challenging for social scientists. With ABM we can make things happen from the bottom-up, and then need to seek reasoning for the phenomena we create, which may not always be evident.

Bonabeau, Eric. “Agent-based Modeling: Methods and Techniques for Simulating Human Systems.” Proceedings of the National Academy of Sciences of the United States of America. 99.10 (2002): 7280-7287. Print.

-sidewalk ballet

How to Define Agent-Based Modeling in Human System Study?

Monday, January 30th, 2012

Agent-based modeling (ABM) has been widely utilized in social science as a powerful modeling tool in the past few years. However, it still remains difficult to conclude an accurate definition of ABM. When it comes to the study of human systems, the situation becomes more complicated due to the uncertainties in human society.

In this paper, Bonabeau conclude that ABM provides three important benefits for simulating human systems. First, it presents a natural description of the study target. Second, it is quite flexible and can be easily adapted for different dimension with the ability to learn and evolve by itself. Finally, ABM captures emergent, which is quite challenging and important in study of human systems. All these features have conceptualized ABM as a necessary tool to handle the complexity in human system studies.

I tend to define ABM as a collection of modeling methodologies, rather than a group of theories. ABM contains a wide body of disciplines, and it seems the number of disciplines will continue increasing. It relies on the methodologies and techniques of statistics, pattern recognition, reinforcement learning, control theories, system identification, game theories, and so on. However, ABM distinguishes itself from the mentioned disciplines by more emphasis on practical usage, not on the solid theory background. For example, ABM can model auction activities without the proof of Nash Equation’s existence, which is not acceptable in game theory studies. Moreover, ABM may utilize reinforcement learning as a tool for self-learning, without any theoretical proof of whether it can converge to the satisfying result or not. Therefore, I think ABM as a collection of practical modeling methodologies, and it will change its definition with different applications.

–cyberinfrastructure

Modeling the Individual for the Whole: Apocalypse Group Dynamics in ABM

Monday, January 30th, 2012

One of the major issues that Bonabeau brings up in his conclusion is the notion that ABMs model a system by simulating the actions of the individual units of analysis and not the group as a whole on the aggregate level. Because of the individual simulation of agents, this process is very computation-intensive and leads to high hardware costs or investment in cloud-computing infrastructure.  He notes that while aggregate-level analysis could be done with just a few equations, it is more complicated and time-consuming to describe individual units.

In the example of modelling a Zombie Apocalypse, I would like to see how the actions of the individual agents affect the outcome for the group as a whole.  As commonly portrayed in Zombie Sci-Fi, even a close encounter with an infected agent can have dire consequences for the entire group that the affected agent belongs to, due to the slow nature of death by the pathogen, and the way in which it manifests itself in its recently dead hosts, thus putting the entire group at risk from an un-noticed bite victim.  I would like to see how the agents would adapt as a group, if one were to add in the preference for both non-infected and infected agents to remain in close proximity to like agents.

 

-Rsmithlal

Using ABM to Model a Zombie Apocalypse

Monday, January 30th, 2012

According to O’Sullivan, the field of Pedestrian models is one of the up and coming areas of interest in what he calls “a locally specific agent-based approach” (O’Sullivan, 543).  In his section on “mid-range regionally or locally specific models”, he states that recent work has been done to simulate crowd-control of large groups of pedestrians in a panicked situation.  I would like to take this approach much further and propose a what-if scenario in which ABM was used to model what would happen in a situation where a real-life pathogenic Zombie outbreak were to occur.

Some suggested parameters to add to the model would be the underlying city infrastructure, locations of food, water and first-aid, locations of weapons and ammunition as well as areas that can be considered safe to occupy.  One of the key features that would have to be programed in the agent’s ability would be non-infected vs infected and how individuals vs groups would respond to either individuals or groups of Zombies. In O’Sullivan’s example, he notes that while the environments that the agents occupy may be complex, the agents themselves are not complex.  Ideally, it would be a simple matter of the flight or flight response, with added thresholds for when the risk of danger is outweighed by the need to venture outside to scavenge materials.

I wish that I understood more about building these sorts of models, as this is a theoretical situation that I would be thrilled to be able to simulate.

-Rsmithlal

Utilizing ABM in GIS Research

Monday, January 30th, 2012

O’Sullivan gives a very good survey about the agent-based models (ABM) in spatial science research. He begins with different definitions of ABM, analyzing their advantages and disadvantages. Then he categorizes ABM applications into three types, with respect to their degree of complexity. As mentioned by Bonabeau, ABM provides an efficient approach to describe the complex systems. O’Sullivan illustrates this point in the paper by delineating spatiotemporal and social ABM representation methodologies. In geography research, ABM provides a powerful tool for modeling geospatial information on computers. However, the challenges should not be overlooked. As ABM represents geospatial information at individual level, the complexity and model verification are becoming more difficult with the increase of agent numbers.

By modeling interesting entities as agencies, ABM reviews the relationship and interactions between these agencies. Sometimes, the study targets in GIS research are in a great number and their relationship can be very complicated for statistical modeling. But ABM can achieve that by modeling each entity or each attribute of the study target, providing detailed models about the intricate phenomenon.

I propose that ABM should be integrated with other geospatial analytical methods in GIS research. By viewing a large number of agencies at aggregate level, we can find several interesting discoveries that cannot be reflected by studying the interactions between the agencies. For example, geospatial statistics can study climate changes at global level, by utilizing geospatial information provided by a large body of agencies which contribute to the climate change. Therefore, utilizing other analyzing tools with ABM can help us in GIS research.

–cyberinfrastructure