Bus Schedules

Bus Schedules

[Arthur Schwarz]

Anyone know any Ada software which can calculate a
bus schedule? This includes major/minor frame calculations
and so on.

art
aschwarz@acm.org
schwarza@gdls.com

Re: Bus Schedules

[Ted Dennison]

In article <s83og4rbeh665@corp.supernews.com>,
  "Arthur Schwarz" <aschwarz@acm.org> wrote:
> Anyone know any Ada software which can calculate a
> bus schedule? This includes major/minor frame calculations
> and so on.

That sounds like it would make a really good programming assignment for
students.

--
T.E.D.

http://www.telepath.com/~dennison/Ted/TED.html


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Re: Bus Schedules

[Arthur Schwarz]

"Ted Dennison" <dennison@telepath.com> wrote in message
news:85vaqu$b2a$1@nnrp1.deja.com...
> In article <s83og4rbeh665@corp.supernews.com>,
>   "Arthur Schwarz" <aschwarz@acm.org> wrote:
> > Anyone know any Ada software which can calculate a
> > bus schedule? This includes major/minor frame calculations
> > and so on.
>
> That sounds like it would make a really good programming assignment for
> students.
>
> --
> T.E.D.
>
> http://www.telepath.com/~dennison/Ted/TED.html
>

Your probably right. I just happen to be the student :-(

I've seen 1553-bus I/F source code on one of the public sites (PAL?)
and thought to save some work by getting software for fixed
scheduling. Maybe not.

Well, maybe you can help me with the algorithm. Some of the
requirements (or objectives) are listed below. I've thought
about using dynamic programming (for some), maybe Integer
programming, and certainly a branch and bound algorithm should
work since the simplist form of the problem is the same as
the 0-1 knapsack. Any ideas?

The objectives are (in what I think is increasing difficulty):
[1] Variable size Minor/Major Frames. All messages are untagged,
    message slots within a Minor Frame are fixed, and Minor Frames
    dense (no slack bits). n-Minor Frames / Major Frame.
[2] Fixed sized Minor Frames. Packing to achieve message
    repetition rates, Minor Frame size optimized for throughput.
    All Minor Frames fixed size and slack bits minimized.
[3] Tagged messages. Minor Frames contain a fixed number of
    messages slots of fixed size. Each message slot in a Minor
    Frame has a set of possible messages which can 'fit'.
    Each message distinguished by their tag. The constituent
    message sets and message set distributions per Major Frame
    needs to be defined.
[4] System performance optimization. Given a command (out message)
    and a response (in message) place responses in in-messages in
    such a way that total system latency is reduced.

And of course there are binary channels, and turn-around latency
issues, inter-frame latencies, error frames, and a host of other
issues TBD after the above. Any ideas?

Thanks Ted.

art
schwarza@gdls.com

Re: Bus Schedules

[Ted Dennison]

In article <s87jcq57eh638@corp.supernews.com>,
  "Arthur Schwarz" <aschwarz@acm.org> wrote:
>
> > In article <s83og4rbeh665@corp.supernews.com>,
> >   "Arthur Schwarz" <aschwarz@acm.org> wrote:
> > > Anyone know any Ada software which can calculate a
> > > bus schedule? This includes major/minor frame calculations
> > > and so on.
> >
...
> I've seen 1553-bus I/F source code on one of the public sites (PAL?)
> and thought to save some work by getting software for fixed
> scheduling. Maybe not.

As I was under the impression you were talking about public transit
busses, perhaps I'd be doing you a favor by *not* helping. :-)

--
T.E.D.

http://www.telepath.com/~dennison/Ted/TED.html


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Re: Bus Schedules

[Charles Hixson]

Depends on what he means.  I once spent several months programming a bus
schedule system in Fox Pro.  One needs to be able to accept some of the
stranger things as input data, and the way times are represented ---
shudder.

Eventually I insisted on some restrictions on the forms that data could
take on arrival.  Then it was possible to make a go of it.  But it was a
several months project.

I think the first step it to get a decent database to hold the data as you
acquire it, define what you will accept as valid times (I ended up using
03:00 -> 25:00).  Figure out whether or not you will be able to get the
times presented in 24 hour format (or even [pray for it] a format based on
the number of minutes since midnight of the base day [that's what I ended
up recalculating all the times to, but if you can get clean data in that
form you'll save yourself a lot of effort!]).

How many users will need to be accessing the system simultaneously?  Can
you just keep it simple, and give them access to a read-only copy?

If it's going to be available on separated machines, do you need to go to
each one to set up an ODBC connection?  Or is it simpler to manage your own
b-tree lookup?  (Depends on implementation considerations.)

Sorry I don't have anything pre-built, but that's a starting list of
considerations (i.e., the one's that I remember off the top of my head).

Ted Dennison wrote:

> In article <s83og4rbeh665@corp.supernews.com>,
>   "Arthur Schwarz" <aschwarz@acm.org> wrote:
> > Anyone know any Ada software which can calculate a
> > bus schedule? This includes major/minor frame calculations
> > and so on.
>
> That sounds like it would make a really good programming assignment for
> students.
>
> --
> T.E.D.
>
> http://www.telepath.com/~dennison/Ted/TED.html
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.