Sunday, December 28, 2008

The the Semantic Web Meets the Social Web 

I've been interested in the semantic web for a long time. Lately, I've gotten more interested in the social web. But this is not really much of a leap. In the following talk from the 2006 The 5th International Semantic Web Conference, Tom Gruber makes the following points:
The Semantic Web is an ecosystem of interaction among computer systems. The social web is an ecosystem of conversation among people. Both are enabled by conventions for layered services and data exchange. Both are driven by human-generated content and made scalable by machine-readable data. Yet there is a popular misconception that the two worlds are alternative, opposing ideologies about how the web ought to be. Folksonomy vs. ontology. Practical vs. formalistic. Humans vs. machines.

This is nonsense, and it is time to embrace a unified view. I subscribe to the vision of the Semantic Web as a substrate for collective intelligence. The best shot we have of collective intelligence in our lifetimes is large, distributed human-computer systems. The best way to get there is to harness the "people power" of the Web with the techniques of the Semantic Web. In this presentation I will show several ways that this can be, and is, happening.

Where the Social Web Meets the Semantic Web

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Discover Nepomuk As a Developer | Nepomuk 

Discover Nepomuk As a Developer | Nepomuk
The Nepomuk framework allows you to create and query metadata for all kinds of resources that make up the KDE desktop. This of course includes the most obvious type of resource: files.

Friday, December 19, 2008

Cognitive Affordance 

cognitive affordance: "According to Gibson, however, perception is not mediated by memory, nor by inference, nor by any other psychological processes in which mental representations are deployed. Perception is the direct pickup of invariants in the optic array. In addition, the invariants are sufficient to specify all objects and events in the organism's environment. No mental contents and processes are needed for perceiving. The end product of perception is not an internal representation of the environment; it is the direct pickup of the invariants in the environment."

This seems to contradict what I said in my previous post.


Saturday, November 29, 2008

Naming Similar Impressions of the World 

I may refer to a man's hand using the phrase "John Black's hand", or the like, and associate with that phrase a transduction of John Black's hand, similar to the transduction formed by a transducer toy, like the one shown below. You may have a nearly identical transduction of that hand, if you have a transducer toy just like ours and you press it against my hand. And you may come to associate the same name with your transduction of that hand as I do with my transduction of it. So there is no need for an agreement between us. But there is a need for our respective transductions to be associated with the same name.

Any particular transduction formed by a transducer toy is as much about the world as it is about the toy. That is one of the reasons for its special appeal. Similarly, the world molds the physics of our memory just as surely as this toy was shaped by my hand. It would be senseless to conceive of a transduction as something separate or independent of the hand that formed it. So too, the idea of mental representations or concepts of the world being separate and independent of the world is senseless. We share names associated with our mutual imprints of the world. And those names refer because the world is one and our sensory apparatus is nearly identical and something has brought us all to associate a common name with our separate transductions.

What must happen for the phrase "John Black's hand" to refer is a common association of that name with our mutual, independent imprinting of John Black's hand using the same kind of transducer. Common transductions, not contracts, form the basis of this kind of concrete reference.

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Sunday, November 23, 2008

The Semantic Web and the Singular Expression of Fact 

On the web, a document needs to be posted once, because it is accessible from everywhere at about the same cost. This is a great advantage over physical publishing since reaching everyone with a publication requires sufficient duplicates and distribution for everyone to have access. Will the Semantic Web provide the the same advantage for factual data?

How many times does the fact that snow is white need to be expressed? For that matter, how many times is snow white? Is there one such fact or is the fact itself repeated over and over again with every snowflake? Let's suppose that there is only one such fact, no matter how many times it is expressed. Then are the many expressions of that one fact superfluous? Could we get away with just one expression of it, provided everyone could link to it with equal low cost?

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Wednesday, January 02, 2008

The Need for a Client View of Context-Independent Symbols 

In the paper Interactively converging on context-sensitive representations: A solution to the frame problem by Robert M. French and Patrick Anselme, the authors describe a robotic simulation of context-sensitive representations:
"Agre and Chapman (1987) developed a simulation, Pengi, in which an agent — a penguin — makes use of context-dependent representations in order to avoid being attacked, in this case, by a bee. Piles of ice cubes are used to allow Pengi to protect himself from being stung by the bee. In addition, Pengi can fight back against the bee by means of a well-placed kick to any ice cube that the bee happens to be directly behind. As for the bee, it has two means to kill the penguin: either by striking an ice cube that Pengi is hiding behind or by stinging the penguin. Space does not allow a full development here of the strategies that the penguin can adopt, nor of his actual sensori-motor abilities (for a detailed description, see Agre, 1997). It is, however, important to note that the penguin has well-developed attentional capabilities that allow him to focus on the salient factors of the situation in which he finds himself.

In the Pengi simulation, all events are contextually determined. There are not context-independent representations, like “ice-cube wall” or even “bee.” The penguin’s representations are, to use Agre’s term, deictic, meaning that they depend on the circumstances in which they are used. Pengi’s representations take the form of the-wall-behind-which-I-will-hide or the-bee-I-want-to-kill (Agre, 1997, p. 267). These representations do not describe context-independent entities; rather they describe some aspect of the environment that is in a particular relation to the agent at a particular moment in time. In other words, rather than a context-independent “bee” representation, the system produces a representation for a particular bee in a particular place at a particular time. The Pengi model avoids the frame problem because the agent is manipulating context-sensitive representations for “bee” that include various salient aspects of situation at hand."

I suspect that biological agents show this kind of continuous context-sensitivity in their sense of the referents of symbols. As the "Great Global Graph" of linked data on the web grows, our automated agents will need to show this kind of selectivity as well. But rather than over-use the word "context", perhaps a better term here would be "personalization". So each clients view of the GGG, the world wide graph of data, will be different, skewed towards the needs of that client. This will probably be done by a collaboration between new kinds of search agents and each client themselves.

Sunday, December 30, 2007

The Semantic Web Meets the Abundance Problem 

The paper Authoritative Sources in a Hyperlinked Environment (2002 PDF) by Jon Kleinberg proposes the following definition of the problem of efficiently and reliably finding documents on the web out of the billions available, a problem he names the Abundance Problem: "The number of pages that could reasonably be returned as relevant is far too large for a human user to digest. To provide effective search methods under these conditions, one needs a way to filter, from among a huge collection of relevant pages, a small set of the most "authoritative" or "definitive" ones."

As the semantic web will build a much more granular set of linked data than the current set of linked documents, this problem will only become worse. So even as search is improved by having more detailed and accurate semantic annotations added, the problem of finding the most authoritative and definitive linked-data will increase. Look for the semantic web version of page-rank algorithms. We will be just as much in need of datum-rank algorithms perhaps?

Swoogle may already be doing this.

Saturday, December 29, 2007

Solutions to the Frame Problem 

In the paper Global Abductive Inference and Authoritative Sources, or, How Search Engines Can Save Cognitive Science* by Andy Clark 2002 (PDF), Clark presents a problem that looks very much like the one I mention in Words (or URI) as Locations in the Fabric of Context, but he refers to it has the "Frame Problem", and attributes its origin with John McCarthy and and Pat Hayes. Clark also presents a potential, partial solution related to searching on the web.

Here is the Abstract:
"Kleinberg (1999) describes a novel procedure for efficient search in a dense hyper-linked environment, such as the world wide web. The procedure exploits information implicit in the links between pages so as to identify patterns of connectivity indicative of “authorative sources”. At a more general level, the trick is to use this second-order link-structure information to rapidly and cheaply identify the knowledge-structures most likely to be relevant given a specific input. I shall argue that Kleinberg’s procedure is suggestive of a new, viable, and neuroscientifically plausible solution to at least (one incarnation of) the so-called “Frame Problem” in cognitive science viz the problem of explaining global abductive inference. More accurately, I shall argue that Kleinberg’s procedure suggests a new variety of “fast and frugal heuristic” (Gigerenzer and Todd (1999)) capable of pressing maximum utility from the vast bodies of information and associations commanded by the biological brain. The paper thus takes up the challenge laid down by Fodor ((1983)(Ms)). Fodor depicts the problem of global knowledge-based reason as the point source of many paradigmatic failings of contemporary computational theories of mind. These failings, Fodor goes on to argue, cannot be remedied by any simple appeal to alternative (e.g. connectionist) modes of encoding and processing. I shall show, however, that connectionist models can provide for one neurologically plausible incarnation of Kleinberg’s procedure. The paper ends by noting that current commercial applications increasingly confront the kinds of challenge (such as managing complexity and making efficient use of vast data-bases) initially posed to biological thought and reason."

My fear was that "the meaning of each term is contained in other documents, and the meaning of each of those terms is again contained in yet more documents and so on until, in the end, in order to understand any URI, you must import some extremely large subset of the entire semantic web."

Here is Clark on the the problem: "The problem of global abductive inference is best appreciated against this backdrop. It is the problem, in a super-compressed nutshell, of how to do inference to the best explanation in a way that is sensitive to whatever is most relevant in the massive body of belief and knowledge that underlies commonsense thinking and reasoning."


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Prior Art


"We are in the habit, I take it, of positing a single idea or form in the case of the various multiplicities to which we give the same name. Do you not understand?" "I do." "In the present case, then, let us take any multiplicity you please; for example, there are many couches and tables." "Of course." "But these utensils imply, I suppose, only two ideas or forms, one of a couch and one of a table." "Yes." "And are we not also in the habit of saying that the craftsman who produces either of them fixes his eyes on the idea or form, and so makes in the one case the couches and in the other the tables that we use, and similarly of other things? For surely no craftsman makes the idea itself. How could he?" "By no means."
Plato, Republic X, page 596a

David Hume

"This convention is not of the nature of a promise: For even promises themselves, as we shall see afterwards, arise from human conventions. It is only a general sense of common interest; which sense all the members of the society express to one another, and which induces them to regulate their conduct by certain rules. I observe, that it will be for my interest to leave another in the possession of his goods, provided he will act in the same manner with regard to me. He is sensible of a like interest in the regulation of his conduct. When this common sense of interest is mutually expressed, and is known to both, it produces a suitable resolution and behaviour. And this may properly enough be called a convention or agreement betwixt us, though without the interposition of a promise; since the actions of each of us have a reference to those of the other, and are performed upon the supposition, that something is to be performed on the other part. Two men, who pull the oars of a boat, do it by an agreement or convention, though they have never given promises to each other. Nor is the rule concerning the stability of possession the less derived from human conventions, that it arises gradually, and acquires force by a slow progression, and. by our repeated experience of the inconveniences of transgressing it. On the contrary, this experience assures us still more, that the sense of interest has become common to all our fellows, and gives us a confidence of the future regularity of their conduct: And it is only on the expectation of this, that our moderation and abstinence are founded. In like manner are languages gradually established by human conventions without any promise. ..." - A Treatise of Human Nature, Chapter 74 by David Hume

John Locke

"...Semeiotike, or the doctrine of signs; the most usual whereof being words, it is aptly enough termed also Logike, logic: the business whereof is to consider the nature of signs, the mind makes use of for the understanding of things, or conveying its knowledge to others. For, since the things the mind contemplates are none of them, besides itself, present to the understanding, it is necessary that something else, as a sign or representation of the thing it considers, should be present to it: and these are ideas. And because the scene of ideas that makes one man's thoughts cannot be laid open to the immediate view of another, nor laid up anywhere but in the memory, a no very sure repository: therefore to communicate our thoughts to one another, as well as record them for our own use, signs of our ideas are also necessary: those which men have found most convenient, and therefore generally make use of, are articulate sounds. The consideration, then, of ideas and words as the great instruments of knowledge, makes no despicable part of their contemplation who would take a view of human knowledge in the whole extent of it. And perhaps if they were distinctly weighed, and duly considered, they would afford us another sort of logic and critic, than what we have been hitherto acquainted with." - AN ESSAY CONCERNING HUMAN UNDERSTANDING by John Locke 1690