- From: pat hayes <phayes@ihmc.us>
- Date: Mon, 26 Jan 2004 18:17:16 -0600
- To: David Martin <martin@ai.sri.com>
- Cc: public-sws-ig@w3.org
>Austin Tate wrote: >> >>At 05:16 PM 16/01/2004 -0600, pat hayes wrote: >> >>>>I have argued that SWSL should simply allow a process description >>>>to be made up of: >>>> >>>>a) a set of activities to be performed, each of which are >>>>considered to have a begin and end time point >>> >>> >>>Suggestion: each process occupies (? lasts for, endures during, >>>takes) a time-interval, and intervals have begin and end >>>timepoints (and indeed are defined by them, uniquely.) Intervals >>>are handy things to have in the ontology anyway. >> >>Agreed... and that is what I meant. An activity always is >>associated with a time interval defined as the begin time point of >>the interval and the end time point of the interval. *** >> >>... snip ... > >Pat, Austin, Jos, and others who have contributed to this thread -- > >In the OWL-S discussions, we fairly often ask ourselves questions like: > "What are the reasoning requirements for OWL-S; that is, what >kinds of questions about an OWL-S service would you like a reasoner >to answer?" >and > "What reasoning will this (some particular) representation or >style of representation support?" > >Unfortunately, we rarely seem to find the time to answer these >questions in a thoughtful manner :-(. > >But since you guys are clearly thoughtful, and we have this thread >about temporal representations, I'd like to put it to you -- > >Will the representation of the temporal aspects of services get used >for practical purposes on the Semantic Web? Yes, for sure. Services seem to be *inherently* temporal. They come and go, they often have dated restrictions (special offer ends midnight), quite a few of them are ABOUT temporally qualified things (reduced fares to Ibizia next month if you buy before Wednesday), and some of them, I would guess, are even concerned with temporal reasoning themselves, eg I would pay substantial $$ for some calendar software that *really* understood time-zones. > If so, what kinds of questions will these representations be used to answer? All kinds. Examples: scheduling and coordinating activities (if I leave on the morning of the 13th, will we have enough time for the meeting in Chicago and still allow me to get to Jakarta in time for Doris' party? Could the suspect possibly have been in the same city as the victim for three consecutive days during February?); reasoning about ages (is this version older that that version?); about time durations (shipping times vary but are usually within 2-4 working days). I wouldn't expect that the temporal reasoning involved in most services applications was very *complicated* - in the sense that, say, the temporal reasoning in a complex planner might be, or that required to follow the sense of a complex narrative - but I would expect it to be kind of ubiquitous, in that it would kind of taint most everything else, and couldn't be relegated to a kind of add-on module. For example, it might be important to know the lifetimes of things, or at least of categories of things, and to be able to distinguish things with an expected short lifetime from those with an expected long lifetime, and certainly those with a lifetime from those that don't have lifetimes (like numbers.) >What are the most important questions for them to be able to answer? Hey, you are out there in the application weeds. We should be asking you about this, surely. But I would guess that a lot of them (could be) boil(ed) down to the form: given some constraints on a bunch of timepoints and intervals (ie pairs of timepoints), is this point in that interval? Or, is there a point in this class of points which is in that interval? > Are there any systems in widespread use that apply temporal >reasoning to solve practical problems (and which might have some >relevance for SW services)? I'll ask James Allen. I'm sure there are. >Note, again, I'm interested to know about uses **for practical >purposes**, in "the real world". As opposed to...? Seems to me that most temporal reasoning is about the real world: its the Platonic worlds that have that eternal feel to them. Or did you really mean, **in actual examples which have actually arisen where there is some chance of someone making $$ **, or some such? No good asking an ivory-tower guy like me about things like that :-). Or did you mean **not uses that depend on arguing about how many endpoints there are on the head of a pin** ? OK,OK, so we spent a lot of time long ago on what seemed like damn silly, er, academic points. But that's all fixed now. Really. Pat -- --------------------------------------------------------------------- IHMC (850)434 8903 or (650)494 3973 home 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32501 (850)291 0667 cell phayes@ihmc.us http://www.ihmc.us/users/phayes
Received on Monday, 26 January 2004 19:17:19 UTC