Review Comment:
This is a revision of a previously submitted (and reviewed) paper on ETL workflows. The paper's previous version was positively evaluated, and the new version is similarly good enough for publication. However, a few issues remain, which I analyse below in detail. Some of the proposed improvements are reiterations of the comments I had in the previous version.
The definition of RUP is still confusing. It was clear to me given the clarifications in the rebuttal, but the reader will not have access to that, and I was not able to understand the role of RUP before reading the rebuttal. F_R is clear, it is a relationship among levels. Then, RUP is defined as a member of this set. So RUP_{L_i}^{L_j} is ONE pair; but apparently this is not the intention of the authors. The intention is to give a name to each such pair (from F_R). Therefore, if I understand well, RUP is a (naming) function that relates each pair (L_i,L_j) \in F_R to some name (e.g., sdw:payMonth, sdw:payYear etc.). Thus, it should be defined like this.
With regards to Definition 3, although I do accept the argument that the correctness of the process is beyond the scope of the current paper, I would appreciate having such a statement before or after Definition 3, along with the acknowledgement that the proposed process is not fail-safe and could be replaced by another (but it is not within the scope of the paper to solve this problem).
Definition 4: I'm confused with the use of e_{t_i} and e_{s_i}. What are these? I assume the authors meant to write c_t and c_s respectively...?? If not, please explain what these symbols stand for.
Page 20-21 (UpdateLevel): as the authors explain, there are three different ways to make the update (called "update types"). Where is this specified? I mean, shouldn't the update type be a parameter of "UpdateLevel"?
Just before Section 6.3: "the resulting inference is asserted in the form of triples, in the same spirit as how SPARQL deals with inference". I'm not sure I understand this sentence, as, to my knowledge, SPARQL does NOT deal with inference. Unless the authors mean something else that I missed.
Minor comments and typos:
- "datatabase"
- Definition 1: I suggest you use bullets (enumerate or itemize) to help the reader grasp the definition (which is quite complex).
- "this operations"
- "another concept-mapping as,"
- Page 22, right column: I suggest to describe Algorithm 2 in its own paragraph. Now it is partly with Algorithm 1, partly with Algorithm 3 and partly in its own paragraph. Perhaps break down the paragraph in line 31, and reorganise the text below...?
- "reduce use 92% fewer"
- Table 4: "Mapping Generartion"
- Page 41, line 37: ";;"
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