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PROV-ISSUE-184: Section 2.1.2 (PROV-DM version as on Nov 28th) [prov-dm]

From: Provenance Working Group Issue Tracker <sysbot+tracker@w3.org>
Date: Wed, 07 Dec 2011 01:43:13 +0000
To: public-prov-wg@w3.org
Message-Id: <E1RY6XR-0007GN-0K@tibor.w3.org>

PROV-ISSUE-184: Section 2.1.2 (PROV-DM version as on Nov 28th) [prov-dm]


Raised by: Satya Sahoo
On product: prov-dm

The following are my comments regarding Section 2.1.2 of the PROV-DM document as on Nov 28, 2011.

Section 2.1.2:
1. "Hence, in our conceptualization of the world, an instantaneous event, or event for short, happens in the world and marks a change in the world, in its activities and in its entities."

Comment: According to this definition, an activity is also an event, since "it happens in the world and marks a change in the world". 
Section states "A generation event may be, for example, the creation of a file by a program, the creation of a linked data set, the production of a new version of a document, and the sending of a value on a communication channel." So, generation event is being used as a synonym of an activity?

In addition, Section 2.1.1 describes a world as "real or not" and includes "digital, conceptual etc." - an event in many scenario will not mark a change in "that" world. For example, person looks at the clock and continues in previous state - it is an event but what changed in the world?

2. "events represent communications or interactions; they are assumed to be atomic and instantaneous." 

Comment: This is contradictory to what is stated in Section, "A usage event may be the consumption of a parameter by a procedure, the reading of a value on a port by a service, the reading of a configuration file by a program, or the adding of an ingredient, such as eggs, in a baking activity." The reading of a configuration file by program is not instantaneous? Adding of eggs in baking activity is not instantaneous? As I have commented on the previous version of DM, this is an artificial requirement for events to be instantaneous.

In addition, why is it required that events are atomic? Adding ingredient in a baking activity is never atomic - egg shells are broken, egg is stirred, egg mix is slowly added to the cake batter, while the batter is mixed continuously etc. Similarly, for events such as reading of file - access is checked, read lock is acquired, i-node is updated, reader process reads content of file etc.
Received on Wednesday, 7 December 2011 01:43:14 UTC

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