Paper Review Form
A. Reader Interest
1. Which category describes this manuscript?
_x_Practice/Application/Case Study/Experience Report
___Research/Technology
___Survey/Tutorial/How-To
B. Content
1.
Please explain how this manuscript advances this field of
research and/or contributes something new to the literature.
This paper
presents a new method to use RDF algebra for optimization and to query RDF
metadata.
1.
Is the manuscript technically sound?
___Yes
___Appears
to be - but didn't check completely
_x_Partially
___No
C. Presentation
1. Are the title, abstract, and keywords
appropriate?
_x_Yes
___No
1.
Does the manuscript contain sufficient and appropriate
references?
___References
are sufficient and appropriate
_x_Important references are missing; more references are
needed
___Number
of references are excessive
2.
Does the introduction state the objectives of the
manuscript in terms that encourage the reader to read on?
___Yes
_x_Could be improved
___No
4. How would you rate the organization of the
manuscript? Is it focused? Is the length
appropriate for the topic?
___Satisfactory
_x_Could be improved
___Poor
5. Please rate and comment on the readability of
this manuscript.
___Easy
to read
_x_Readable - but requires some effort to understand
___Difficult
to read and understand
___Unreadable
Section II. Evaluation
Please
rate the manuscript. Explain your choice.
___Award
Quality
___Excellent
___Good
_x_Fair
___Poor
Section III. Detailed Comments
The paper shows the necessity of RDF algebra for
optimization and querying RDF metadata. the RDF and
RDFS proposed by W3C, can be used for describing metadata, but not for querying
metadata.
Three main approaches for
querying RDF (meta)data have been proposed.
The first approach (supported in
the W3C working group by Stanford) is to view RDF data as a knowledge base of
triples. Triple, the successor of SiLRI (Simple Logicbased RDF Interpreter), maps RDF metadata to a
knowledge base in Horn Logic (replacing Frame Logic). A similar approach is
taken in Metalog, which matches triples to predicates
in Datalog, a subset of Horn Logic. In this way one
can query RDF descriptions at a high level of abstraction: the querying takes
place at a logical layer that supports inference.
The second approach (proposed by
IBM) builds upon the XML serialization of RDF. In the “RDF for XML” project
(recently removed), an RDF API is proposed on top of the IBM AlphaWork’s XML 4 Java parser. In the context of the same
project a declarative query language for RDF (RDF Query) [27] was created for
which both input and output are resource containers. One of the nice features
of this query language is that it proposes operators similar to the relational
algebra, leaving the possibility to reuse some of the 25 years experience with
relational databases. Unfortunately, the language fails to include the inference
rules specific to RDF Schema, loosing description semantics.
The third approach (coming from
ICS-FORTH in