Re: Time intervals through predicate

OK, given that, then I don't see why there is a separate concept needed 
for time-varying graph as the result of applying a windowing operator to 
a stream. The result could be simply a stream with appropriate predicates.

Tara

On 6/12/15 11:24 AM, Gray, Alasdair J G wrote:
> Hi Tara,
>
> This is exactly my motivation for wanting to have the predicate here. 
> Then we can accurately account for the relationship between the graph 
> and time, and as you point out model intervals if required.
>
> Alasdair
>
> On 12 June 2015 at 15:56:42, Tara Athan (taraathan@gmail.com 
> <mailto:taraathan@gmail.com>) wrote:
>
>> If we truly allow any predicate to be used for "p" in the time-stamped
>> graph (g, p, t), then we can emulate an interval time stamp through p.
>> For example, p could come equipped with a duration, with the meaning
>> that the graph holds during the interval starting at t, with this
>> duration. The duration could be specified with a query string parameter,
>> providing a family of predicates, each one corresponding to a particular
>> duration.
>>
>> There could be different predicates for the case when t is the start
>> time, end time or center of the interval. This allows choosing any one
>> of these characteristics for the primary ordering, while variation in
>> the duration could lead to a secondary ordering, if a total order of the
>> stream is desired.
>>
>> Does this seem reasonable?
>>
>> Tara
>>
> -- 
> Alasdair J G Gray
> Lecturer, Heriot-Watt University
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