As you may remember, my goal for reading this paper is a better understanding of the theories behing QSR and thus be able to make a better decision regarding what theory to use to represent my problem. I know, I haven’t talked about what “the problem” is yet, but suffice it to say I want to reason about some objects in space.
So far, I’ve concluded that I needed spatial qualitative reasoning (instead of qualitative reasoning); I have decided on my spatial entities (regions) and topology (to describe the relationships among my entities) and I have defined my basic relationships between my entities (binary relations). So let’s go on, what other factors do I need to consider? Read more »
Things are starting to get hot and heavy now. We will be seeing some mathematical definitions soon. To recap, so far we’ve decided which kinds of spatial objects (points, lines, regions) as well as what primitive non logical symbols to allow in our theory. We’ve settled on regions and (binary) relations.
The question is now, out of the possible set of relations out which one should you choose? Different sets have different advantages and disadvantages. Understanding these will help in choosing a proper theory for your problem. I might even find that my present course of action is not the best, maybe RCC-8 will not allow me to represent my problem properly.
Varzi showed that mereology is not sufficient by itself, but that integrating mereology and topology will. Hence we arrive at mereotopology. Given that topology already deals with spatial entities and as such is a necessary component, how should we work in these topology theories? Three general strategies are available:
- Generalize mereology by adding topological primitives.
- Topology is the primary theory and mereology is secondary.
- Mereology is primary theory and topology is secondary.
To paraphrase: “An important familiy of theories steam from the intuition that parthood and connection cannot be defined in terms of each other.”
For now, I’m going to take a detour and explore mereotopology in more detail to ensure that I fully understand these implications. Please subscribe to my feed to hear about my next adventure.
Are you considering using QSR to solve your research problem? Looking at “Qualitative Spatial Representation and Reasoning” (A. G. Cohn and J. Renz) and need help deciding if you want to spend the time reading the paper?
Deciding whether or not to use QSR to solve a particular problem is an important first step. Do you need to do spatio-temporal reasoning about objects in space? Are you looking for qualitative information, such as “Object A is close to Object B and partially covers Object C” or are you looking for detailed quantitative information, such as “Object A is 5 mm from Object B”? QSR deals with qualitative information.
Let’s assume that qualitative spatial reasoning will suffice for your research problem, how do you decide what theory to use. This paper gives you an overview of the current (2007) state of affairs in QSR and will help you figure out where to start your reading.
Read more »
Now that I have a better understanding of QSR and the theory behind it, I thought it would be a good idea to reread some articles. I often find, that I can gain greater understanding about research by re-reading articles. This particular article by Cohn and Renz part of a book on Knowledge Representation (KR) (A. G. Cohn and J. Renz, Qualitative Spatial Representation and Reasoning, in: F. van Hermelen, V. Lifschitz, B. Porter, eds., Handbook of Knowledge Representation, Elsevier, 551-596, 2008. ). I had already reread sections 1.1 and 1.2 when I thought of writing about it, so my thoughts on those sections will come at a later point.
I have continue my research into the field of QSR and arrived at RCC-8 for the moment. My task is to decide if RCC-8 or one of its descendants will be suitable for our project. Here’s an interesting tidbit before I get started, RCC used to stand for Randell, Cui and Cohn, the authors who first introduced RCC. It has since changed and now refers to Region Connection Calculus, which is a better description. It’s a good thing the the initials didn’t have to change.
Before I talk about the theory behind RCC-8, I think an example is in order. If you can’t wait for my next write-up on RCC-8 go ahead and check out the wikipedia page. I’m also going to borrow the example from the page, but I’m going to show how the path-consistency algorithm works and how the composition table is used. Read more »
I’m working on a new project in the field of bio-informatics, about which I will write at a later point. As part of that project, I’m looking at spatio-temporal reasoning. I did some high level research and eventually found the field of qualitative spatial reasoning (QSR), a subfield of AI. QSR seems to provide solutions to problems similar to ours and I decided to explore further. Read more »
QSR, Research, bioinformatics | julia | 
March 23, 2009 10:58 | 
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