Remember that the conceptual flight object also has a life cycle, not just the individual flight instances. And it is specific to an airline or other institution and to the starting and ending locations, day/time slots, and must be authorized by the different terminal institutions involved (e.g., gate and take-off slots), not just the airline or FAA-equivalent. So each flight conceptual object is a separate individual just as much as the flight instances within each flight object are. Part of the 4D evolution of the conceptual flight object is how many instances of individual flights occurred or were cancelled and when they occurred. It could also change departure/gate slots or code shares over time. Note that a code share is essentially a merger of (or superposition?) two conceptual flight objects (from two different airlines) with the same flight instance serving both.
Some other identity issues that arose which I did not mention in my earlier post were those of “containerization” and “docking/separation”. Generally these don’t come up in civilian air travel today, but there are enough instances in other air operation domains to suggest that any international air space management scheme should be prepared to deal with such cases. They are similar to code shares, but involve physical envelopment or linking in flight. Should two flight object instances become one (docking/envelopment) or one become two (separation/ejection) in mid-flight? Or should they persist with their original flight identifier and be flagged with some other indicator that they are now physically linked together? How does this mesh with radar information showing only a single track for two flight instances? The problem, of course, is that what constitutes an individual for air traffic management purposes changes in such situations. In the extreme, we could envision individual passengers and luggage departing an aircraft in mid-air and using “bat-suits” and “GPS precision homing kits” to fly directly to their individual destinations.
Regarding the Concorde tourist jaunts, I wonder if they were treated as an individual aircraft/tail number with a filed flight plan (like most general aviation air traffic) vice a scheduled airline flight? The scope of what types of flying entities should be included in the flight object data services was a big unresolved issue. UAVs are a big issue currently, and of course, some military aircraft abide by civilian air traffic control rules/processes, and others don’t. So multiple namespaces for identifying flying entities is pretty much a given.
Hans
From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx [mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Matthew West
Sent: Saturday, December 15, 2012 9:21 AM
To: '[ontolog-forum] '
Subject: Re: [ontolog-forum] Fwd: Ontologies and individuals
Dear Hans,
Not to prolong the discussion – which has been good from my perspective, at least – but your points about a full 4D perspective makes my wish we had you involved in the development of the Flight Object Data Services Pattern in NCOIC a couple of years ago. An interesting aspect of that concept was that a flight object represented both the full 4D evolution of a “flight” from concept to actual operations by some airline, as well as the actual instances of that “flight” that occur each day, or at whatever the scheduled interval might be. The flight identifier is used for both the conceptual entity of the flight, which usually persists for years, and the actual flight instances that occur at the scheduled intervals.
MW: Well the 4D object here would be the actual flight instances, this would be a kind of activity, and to be fair, some 3D ontologies (such as BUFO) give a 4D treatment to activities (and a 3D treatment to physical objects). However, in a 4D treatment the flight would consist of temporal parts of the plane, crew, and passengers. Whilst the conceptual flight you mention could be the aggregate of these flights, it is more likely this is a specification (a service). So a class or type of flight instance. I would also be surprised if the flight number was the identifier for the flight instances, though I can see that the flight number and date might be used. Of course you also have to decide how you deal with code shares.
There were other interesting individual identity aspects of this exercise, such as the assumption that flights went from place to place (restricted to ICAO codes), which would have created challenges for Virgin Airways’ planned suborbital jaunts – and eventual orbital operations, or for more mundane mid-air refueling operations. The latter get around this problem today by creating “pseudo-ICAO” codes for the “racetrack in the sky” refueling points and treat it as a “stop” for the refueling aircraft before it returns to its starting airbase.
MW: Hmm. It should not have been too difficult to allow a flight to return to the place it started from. Never mind suborbital jaunts, Concorde used to run trips for enthusiasts several times a year that were just about going up, getting supersonic and returning.
Regards
Matthew West
Information Junction
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Hans
Dear Hans,
You seem to be approaching this from a 3D perspective.
I think the identifiers are of the individuals in the context of specific roles within a larger institutional/social context. They are not identifiers of the roles themselves, since obviously many, if not all, individuals have these same roles.
MW: From a 4D perspective the identifiers are of the state of individual that is playing the role, rather than the individual for the whole of its life. For example, a Passport No. or a Driving License No only identifies particular states, not the person for the whole of their lives.
HP: Collective contexts have duration scope, so I do take a 4D perspective
Indeed, what identifiers of individuals are there that don’t have a specific context and perspective associated with them?
MW2: 4D is more than just accounting for time and change, it is a particular way to do it. The difference lies in the difference taken in the nature of individuals, and identity. A 3D approach says that an individual is wholly present at each point in time, whereas a 4D approach takes individuals as extended in time as well as space (so it is not wholly present at each point in time). Strong 4D goes further and says that the spatio-temporal extent is the identity basis for individuals, i.e. if two individuals have the same spatio-temporal extent, then they are identical.
MW: Sometimes identifiers are created with that purpose, a birth certificate number for example.
HP: But my point was that even birth certificates have a particular institutional context – and can get lost or destroyed. They don’t represent a context-free identity for a person and are typically not coupled directly to a person biometrically and not all have numbers. I don’t know of any system that uses birth certificate numbers as identifiers for people.
MW: How about the register of births? But I agree, identifiers are arbitrary.
That was why I made the comment “DNA notwithstanding” in my original post. By the way, DNA is not guaranteed to be a unique identifier, either – although evolution has endowed us with facial recognition capabilities that do a pretty good job. Maybe we will all live to see the day of a “context-free” individual identifier implanted in all individuals prior to birth? And what identifiers are inherent in individual entities that are not people? Maybe those laser-engraved serial numbers in some diamonds? Aren’t those put there by or under the aegis of a specific institution?
MW: Well this is a different point. The nice thing about unique identifiers is how many of them any individual can have. Being unique only means that within that context the identifier is managed to only refer to one thing. It does not prevent there being other unique identifiers for the same thing, and it does not prevent different identifiers for the same thing using the same scheme (though you might attempt that). For example, a person might try to obtain more than one Social Security Number so they can commit benefit fraud.
The point is that all identities
MW: Identity is different from identifier…
HP: Correct! But information systems generally don’t make that distinction because the only way they have of distinguishing among individuals is through identifiers – which have context, usually implicit and overlooked. And one purpose of the “entity primacy” principle is to make developers explicitly aware of that distinction so that they don’t mistake the identifiers they are using for individuals for the identity of those individuals (which is their own and inherent in their existence in some reality). The best we can do is to get socio-political agreement on some “near-innate” identifier for individuals, such as VINS for motor vehicles intended for use on public roads and MAC addresses for Ethernet devices. Such identifiers are useful for information sharing interoperability among diverse contexts about the same individuals. But we don’t really have such an identifier for people (yet). Maybe some “superDNS” identifier certificate issued independently of national/local jurisdiction before birth to all people (like VINs) will be brought about thanks to the Internet, but I’m not holding my breath. Or maybe some biometric will be found that can serve as this “near-innate” identifier on the network. And we need to be vigilant and remember that even these identifiers are not the same as identity and that the individuals may have other identifiers in other contexts.
MW: I think it is unlikely there will be a single universally accepted identifier for people for some considerable time. It’s a political issue rather than a technical one.
Regards
Matthew West
Information Junction
Tel: +44 1489 880185
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This email originates from Information Junction Ltd. Registered in England and Wales No. 6632177.
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Regards
Matthew West
Information Junction
Tel: +44 1489 880185
Mobile: +44 750 3385279
Skype: dr.matthew.west
matthew.west@xxxxxxxxxxxxxxxxxxxxxxxxx
http://www.informationjunction.co.uk/
http://www.matthew-west.org.uk/
This email originates from Information Junction Ltd. Registered in England and Wales No. 6632177.
Registered office: 2 Brookside, Meadow Way, Letchworth Garden City, Hertfordshire, SG6 3JE.