Re: Bidirectional Binary Self-Joins
From: paul c <toledobythesea_at_oohay.ac>
Date: Sat, 31 Mar 2007 02:13:08 GMT
Message-ID: <UsjPh.2130$DE1.768_at_pd7urf2no>
>
>
> actually there are flights that do take off simultaneously. i blaim
> it on TWA ... the first time I remember seeing it was very early 70s
> .... twa had plane parked overnight in san jose ... first thing in the
> morning, it took off for SFO, with two different flight numbers. in
> san fran, some of the passengers ... who thot they had a "direct"
> flight with no connections ... found that while their flight number
> went direct, they had a "change of equipment" (NOT a connection) ...
> since the original equipment continued outbound from SFO with one of
> the flight numbers ... and some totally different equipment assumed
> the other flight numbers for a different destination.
>
> in a different life, we were given the opportunity to rewrite ROUTES
> .... one of the common airline res system applications ... i.e. finding
> flights/times/etc to get from origin to a destination. as part of the
> effort, we were provided a machine readable copy of the OAG ... with
> all world-wide commercial flight segments. I believe the "worst" I
> found was what appeared to be six different flight segments
> .... i.e. different flight numbers but identical equipment, identical
> departure times from the same airport and identical arrival times at
> the same destination airport.
>
> when i expressed my opinion about the "change of equipment" scenario
> .... the explanation was that agent reservation screens (as well as
> printed manuals) typically ordered all direct flights first on the
> screen (or in books) before all connecting flights. judicious use of
> multiple flights numbers for the same equipment, got a lot of things
> moved up to the top of the screen (with people who were avoiding
> connecting flights found themselves faced with "change of equipment")
>
> the other "benefit" (of creating multiple different flight nos for the
> same equipment), was typical reservation system provided agents with
> only a limited number of connecting flight operations. more complex
> travel scenarios required agents to manually stitch together some
> number of connections. use of multiple flight numbers per equipment
> .... could provide some additional trip planning help to agents.
>
> so one of the "ten impossible" things (current ROUTES couldn't do and
> we were suppose to implement), was being able to find connections
> between any two airports (some 4k plus) in the world. for demo, they
> would give two airports codes ... frequently ones that nobody had ever
> heard of before on opposite sides of the world. there were some that
> took more than 24hrs elapsed time with 5-6 different connections.
>
> being able to automatically find any possible origin/destination
> .... at least eliminated the excuse (for multiple flight nos per
> equipment) that the agent was being helped on how to get from any
> possible origin to any possible destination.
Date: Sat, 31 Mar 2007 02:13:08 GMT
Message-ID: <UsjPh.2130$DE1.768_at_pd7urf2no>
Anne & Lynn Wheeler wrote:
> paul c <toledobythesea_at_oohay.ac> writes:
>
>>Not trying to change the example, which I think is excellent, but this >>reminds me of the airline game. In flight and related systems, it is >>enough to use airline code, flight number (an invented number), date, >>scheduled departure and arrival time in hours and minutes, departure >>airport code and destination airport code to indicate a flight (or >>flight segment, the term that biz uses). One could ask what prevents >>two different flights with that recorded key, from taking off from the >>same large multi-runway airport in the same minute? The answer is the >>key itself, which is embedded in every manual and computer method the >>controllers, airport personnel and so forth use, which doesn't include >>a runway code, nor anything close to scheduled times measured in >>seconds.
>
>
> actually there are flights that do take off simultaneously. i blaim
> it on TWA ... the first time I remember seeing it was very early 70s
> .... twa had plane parked overnight in san jose ... first thing in the
> morning, it took off for SFO, with two different flight numbers. in
> san fran, some of the passengers ... who thot they had a "direct"
> flight with no connections ... found that while their flight number
> went direct, they had a "change of equipment" (NOT a connection) ...
> since the original equipment continued outbound from SFO with one of
> the flight numbers ... and some totally different equipment assumed
> the other flight numbers for a different destination.
>
> in a different life, we were given the opportunity to rewrite ROUTES
> .... one of the common airline res system applications ... i.e. finding
> flights/times/etc to get from origin to a destination. as part of the
> effort, we were provided a machine readable copy of the OAG ... with
> all world-wide commercial flight segments. I believe the "worst" I
> found was what appeared to be six different flight segments
> .... i.e. different flight numbers but identical equipment, identical
> departure times from the same airport and identical arrival times at
> the same destination airport.
>
> when i expressed my opinion about the "change of equipment" scenario
> .... the explanation was that agent reservation screens (as well as
> printed manuals) typically ordered all direct flights first on the
> screen (or in books) before all connecting flights. judicious use of
> multiple flights numbers for the same equipment, got a lot of things
> moved up to the top of the screen (with people who were avoiding
> connecting flights found themselves faced with "change of equipment")
>
> the other "benefit" (of creating multiple different flight nos for the
> same equipment), was typical reservation system provided agents with
> only a limited number of connecting flight operations. more complex
> travel scenarios required agents to manually stitch together some
> number of connections. use of multiple flight numbers per equipment
> .... could provide some additional trip planning help to agents.
>
> so one of the "ten impossible" things (current ROUTES couldn't do and
> we were suppose to implement), was being able to find connections
> between any two airports (some 4k plus) in the world. for demo, they
> would give two airports codes ... frequently ones that nobody had ever
> heard of before on opposite sides of the world. there were some that
> took more than 24hrs elapsed time with 5-6 different connections.
>
> being able to automatically find any possible origin/destination
> .... at least eliminated the excuse (for multiple flight nos per
> equipment) that the agent was being helped on how to get from any
> possible origin to any possible destination.
p
p Received on Sat Mar 31 2007 - 04:13:08 CEST