OntoBroker - Mature and approved semantic middleware
This is a revised manuscript, now accepted for publication, following an "accept with minor revisions." The reviews of previous rounds are below.
Reviews for the resubmission:
Solicited review by Jacopo Urbani
The quality of the paper has improved and most of the concerns were
addressed. Unfortunately, I cannot argue for a complete acceptance
since I couldn't find in the new paper the two figures about the
openrule benchmark on multicores and load performance that are
mentioned in the rebuttal letter.
Even the text is more detailed on these two issues, the two mentioned figures
are supposed to answer to my concerns about the multi-core performance
and loading time so I would like this issue to be clarified before
proceeding to a further stage.
Some minor comments that appeared in the new version:
"makes it easy do connect" -> to connect
- It would be clearer if at page 6 there is a reference to the
benchmarks in 2.2. Now the reference is only in section 2.2 but it's not so
useful since there the topic is different, while it would have enriched the
explanation if set it in sec. 2.1.
- page 12: reference to dbpedia is missing
- page 14: (missed from the previous revision) a citation or a reference
to the competion and the prize to ontobroker should be added.
Solicited review by anonymous reviewer:
In my first review I strenuously objected to the highly misleading use of
the so called "ObjectLogic" as a new kind of invention. Unfortunately, in
the revised paper the author persists and piles up even more gibberish on
First, ObjectLogic (as well as F-logic2 mentioned in the paper) is nothing
but a commercial gimmick, which has no place in a serious scientific
journal. None of this is original or belongs intellectually to the author
of that paper.
Second, the very term Object Logic (or O-logic) was introduced by Maier
almost 25 years ago and then further developed by Kifer and Wu. Object
Logic is not an extension of F-logic, but a subset of it.
Third, the author now claims that ObjectLogic is an extension of F-logic
with a "lot of modeling features", like property hierarchies, complex logic
formulas, and builtins. In reality, all these issues are completely trivial
and have been discussed in
and various other papers, including the original 1995 paper on F-logic.
The mention of builtins as a "language extension" is particularly amusing.
The author does not seem to have a vaguest idea of what constitutes a
credible language extension.
Claiming credit for trivialities and unoriginal ideas can hardly enhance
the reputation of the author.
Finally, I may not have noticed this before, but the title of the paper is
both hilarious and unbecoming, fitting well with the general tendency of
unrestrained self-praise permeating the paper. "Mature and approved
... middleware"??? Approved? By whom?
I do not think that a self-respecting journal can afford publishing a paper
with such stylistic and integrity flaws. The author must either eliminate
the serious issues that I and other reviewers pointed out or face rejection.
Reviews for the original submission:
Solicited review by Jacopo Urbani
The paper presents the tool "OntoBroker" which is a generic middleware
for storage and processing of RDF data. The paper describes the
the system and highlights the features and performance.
The paper describes the product (OntoBroker) in a clear and concise
way. The scientific output of the paper is little but since the paper
is under the Tools track this is not an issue. The features are
presented in detail but the paper requires an overall improvement.
The main problem the paper is that the performance analysis is
minimal. One of the selling points of this product is that it can be
used in many different scenario (which are presented at the end of the
paper) but only the tool's performance with the Open rule Benchmark is
presented. It is not explained how the system performs in all the
other cases and such explanation would make the work more
credible since currently many statements in the papers are not
supported by any number (see below for a list of them).
It is not clear whether the system has some limitations (that is one
of the criteria to evaluate this paper). In order to make the paper a
more complete description of the system, I suggest that the author(s)
add a section describing where the system doesn't work well or worse
than the others (if there is such case of course, anyway more
explanation on it is needed).
In general I argue that this paper should be accepted, but only under
the condition that the problems described below are fixed.
- The abstract is missing and it should be added in the final version of
- The quality of the pictures is low and it is difficult to read them.
- Page 3: there is a question mark that I don't know the meaning of.
- ObjectLogic should be introduced an properly explained since it is a
fundamental part of the system.
- Page 5: topdownto use (should be splitted)
- Page 5: EDB is used but not introduced.
- Page 6: "In general, it can be said that dynamic filtering beats
magic sets". This is an example of statement that should be
motivated by some numbers. Have you run experiments to conclude
this? Do you refer to existing work in literature? In both cases,
more explanation is needed.
- Page 9: "This (the architecture) supports multi-core/multi-processor
hardware extremely well". Again, this statements requires more
explanation. What does "extremely well" means? Some experiments
should be added to justify this sentence.
- Page 10: "The relational layer may currently store up to 500 million
triples in a persistent way". More explanation is needed: what kind
of relational database do you use? Can we load more triples in the
system or is 500 millions the maximum that it can handle? How long
does it take to load this amount? (In particular this last question
is very important to determine the quality of the engine).
- Page 11: "In the meantime, the W3C has issued several
recommendations. OntoBroker supports all of those". Please
reformulate this sentence. It is unclear.
- Page 11: "ontoprise" without the first capital letter
- Page 12: "viz. ontologies" please avoid abbreviations unless it is
- Page 13: "can be integrated in a very comfortable way". The "very"
adjective sounds as an attempt of overselling.
- Page 15: "In several production lines, an impressive amount of
specialized machines...". What is impressive: 10,100, 1000 machines?
- General: please, add more references to RDF, OWL, LOD and the other approaches you used for the comparison.
Solicited review by anonymous reviewer:
This is an overview of the OntoBroker system and its applications.
The paper describes briefly the theoretical underpinnings of the system,
then goes into the performance and application issues.
Apart from the occasional English lapses, this is a well-written overview.
My only concern is with the paper hyping up what they call "ObjectLogic" as
the "best of the breed" as if this is some kind of a nontrivial theoretical
or practical invention. This is bound to mislead an unsuspecting reader to
which I object. In reality, ObjectLogic is nothing by a combination of
several well-known ideas that are completely orthogonal to each other and
whose desirability or combination in one system was never in doubt. It is
just that different systems stress different combinations. I would
therefore request that the authors tone down the hype a few notches.
The following is a list of minor comments (mostly correction of English lapses).
p. 1 productive --> production
p.2 allows the connection of --> supports connectivity with
In the following chapter ...: Chapter or section?
p.3 integrate into existing (?): a spurious question mark?
and hence positioned on top ---> layered on top
p.4 the following way --> as follows
p.6, right above QSQ: dynamic filtering beats magic sets in the first case.
which case? Unclear.
Sec 2.2, l.1: some successive -> several successive
line below Fig 4: pure data flow --> purely data flow
sec 2.6: turing --> Turing
Sec 3, l.1: live-time? Did you mean run-time? Or real-time?
Sec 6.2: temperatures, pressures --> temperature, pressure
after the starting procedure --> after start.