=Paper= {{Paper |id=Vol-1766/oaei16_paper5 |storemode=property |title=DisMatch results for OAEI 2016 |pdfUrl=https://ceur-ws.org/Vol-1766/oaei16_paper5.pdf |volume=Vol-1766 |authors=Maciej Rybiński,María del Mar Roldán-García,José García-Nieto,José F. Aldana-Montes |dblpUrl=https://dblp.org/rec/conf/semweb/RybinskiGGM16 }} ==DisMatch results for OAEI 2016== https://ceur-ws.org/Vol-1766/oaei16_paper5.pdf
               DisMatch results for OAEI 2016

Maciej Rybiński ⋆ , Marı́a del Mar Roldán-Garcı́a, José Garcı́a-Nieto, and José
                                F. Aldana-Montes

       Dept. de Lenguajes y Ciencias de la Computación, University of Malaga,
           ETSI Informática, Campus de Teatinos, Malaga - 29071, Spain
                 maciek.rybinski@lcc.uma.es, mmar@lcc.uma.es,
                      jnieto@lcc.uma.es, jfam@lcc.uma.es



        Abstract. DisMatch is an experimental ontology matching system based
        on the use of corpus based distributional measure for approximating se-
        mantic relatedness. Through the use of a domain-related corpus, the
        measure can be applied to a problem focused on the domain of the cor-
        pus, here being the Disease and Phenotype track. In this paper, we aim
        to briefly present the proposed approach and the results obtained in the
        evaluation, as well as some early conclusions regarding the performance
        of DisMatch.

        Keywords: Ontology Matching, Bench-marking, Lexical Semantic Re-
        latedness


1     Presentation of the system

1.1    State, purpose, general statement

It has been demonstrated that corpus based measures can be used to success-
fully approximate human judgment, w.r.t. semantic relatedness between pairs
of concepts [1,3,4]. DisMatch is an experimental system built for the purpose
of evaluating the applicability of a state-of-the-art domain-focused corpus based
measure of semantic relatedness, to a task of ontology alignment.
    For a pair of ontologies, DisMatch calculates the matrix of semantic related-
ness between labels representing their concepts. It then uses this matrix as the
input for the classic algorithm of Similarity Flooding [2], in order to incorporate
the taxonomic information into our final results.


1.2    Specific techniques used

The workflow of DisMatch can be broken down into the following steps:

 1. Preprocessing: extraction of the taxonomies and labels of the concepts.
 2. Assigning distributional representations to the concepts of the ontologies
⋆
    Corresponding author maciek.rybinski@lcc.uma.es
 3. Calculating the semantic relatedness for the pairs of concepts of the respec-
    tive ontologies
 4. Calculating the similarity propagation given the taxonomies and initial re-
    latedness scores (SimFlood)
 5. Calculating the final similarity scores
 6. Filtering

    In step (2), we use vector based representations of an ESA (Explicit Seman-
tic Analysis [1]) style approach adapted to the biomedical domain related use.
The representations are created for inputs that are the labels of individual con-
cepts. The distributional representations are obtained through a combined use
of Wikipedia and a domain-focused corpus of scientific documents, i.e. Medline.
    In step (3), we use the vectors from step (2) to calculate the relatedness
approximation as the cosine similarity of these vectors. To calculate the similarity
propagation in step (4), we use the very basic version of the algorithm applied to
the taxonomic structures. We do however restrict the propagation graph size by
not including the nodes that do not surpass a certain minimal initial relatedness
threshold.
    We calculate the final similarity scores (step 5) as an average between the
initial scores (semantic relatedness) and the similarity propagation output. This
gives more importance to the relatedness score (which is the point of our experi-
ment), and also caters for cases in which Similarity Flooding is poorly applicable.
    The filtering is done by: i) accepting only a maximal number of candidate
matches per node of an ontology; ii) eliminating candidate matches below a cer-
tain similarity threshold; iii) accepting a globally maximal number of candidate
matches.

1.3    Adaptations made for the evaluation
No specific adaptations were made for the experiments, apart from minor changes
of the filtering parameters (i.e. the global number of candidate matches accepted
in the final alignment).

1.4    Link to the set of provided alignments
The set of provided alignments is available in URL http://bit.ly/2dPA9H5


2     Results of the Disease and Phenotype track
DisMatch has been evaluated in both tasks of the Disease and Phenotype track:
HP-MP (alignment of Human Phenotype Ontology with Mammalian Phenotype
Ontology) and DOID-ORDO (alignment of Human Disease Ontology with Or-
phanet Rare Disease Ontology). A summary of results is reported in the Official
site of OAEI 2016::Disease and Phenotype Track1 .
1
    In URL http://oaei.ontologymatching.org/2016/results/phenotype/.


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                   Table 1. Unique mappings in the HP-MP task

          OM             Unique   Precision   Positive    Negative
          Algorithm  Equivalence  (Manual Contribution Contribution
                      Mappings Assessment)       (TP)         (FP)
          AML                122     0.8667     8.63%        1.33%
          DisMatch          291      0.8333   19.80%         3.96%
          FCA Map             26     0.9615     2.04%        0.08%
          LogMap             130     0.9330     9.90%        0.71%
          LogMapLite           0     0.0000     0.00%        0.00%
          LogMapBio          176     0.9330    13.40%        0.96%
          LYAM++             226     0.7000    12.91%        5.53%
          PhenoMF             89     1.0000     7.27%        0.00%
          PhenoMM             85     1.0000     6.94%        0.00%
          PhenoMP             80     1.0000     6.53%        0.00%
          XMap                 0     0.0000     0.00%        0.00%
          Totals           1225               87.42%       12.58%




    It can be observed that the results of DisMatch are relatively far off the silver
standard created in the evaluation process. We believe that this is largely due
to setting up the system with parameters that resulted in overly strict filtering
that created a relatively low number of mappings. In turn, the low number of
mappings led to poor recall, both in the silver standard evaluation and w.r.t.
the set of manually created mappings.

    The precision of DisMatch in the HP-MP alignment looks quite promising,
especially if we consider the number of unique alignments produced by the sys-
tem. Out of the total of 644 mappings, 353 mappings are confirmed by at least
one another system (thus falling into ’correct’ category in the silver standard
2). Out of these 353, 293 are confirmed by at least 2 other systems (’correct’ in
silver standard 3). The remaining 291 mapping are unique to DisMatch. Table 1
presents an overview of unique mappings produced by the respective systems.
The precision of the unique mappings produced by Dismatch is estimated at
0.8333, which accounts for a large portion of unique and correct mappings dis-
covered by our system. In this regard, the proposed approach obtained the high-
est percentage of positive contribution (19.80%), with a relatively low negative
contribution (3.96%).

    In the case of DOID-ORDO alignment, the performance of our system is
limited, as it is affected not only by the low recall related to the poor parameter
selection, but also by the inability of our structural mapping component to cope
with the structure of the Orphanet ontology. This shortcoming will be addressed
in the future versions of DisMatch. Nonetheless, as shown in Table 2, even in
this setting, the system managed to produce a considerable number (estimated
40% of 259 is > 100) of correct unique mappings.


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               Table 2. Unique mappings in the DOID-ORDO task

          OM             Unique   Precision   Positive    Negative
          Algorithm  Equivalence  (Manual Contribution Contribution
                      Mappings Assessment)       (TP)         (FP)
          AML                308     0.8667    30.40%        4.68%
          DisMatch           259     0.4000    11.80%       17.70%
          FCA Map             61     0.8330     5.79%        1.16%
          LogMap              80     0.9000     8.20%        0.91%
          LogMapLite           7     0.5000     0.40%        0.40%
          LogMapBio          144     0.9667    15.85%        0.55%
          LYAM++               0     0.0000     0.00%        0.00%
          PhenoMF              3     1.0000     0.34%        0.00%
          PhenoMM              0     0.0000     0.00%        0.00%
          PhenoMP              0     0.0000     0.00%        0.00%
          XMap                16     0.5625     1.03%        0.80%
          Totals            878               87.42%       12.58%



3   General comments

Relatedness measure seems to capture non-trivial matches better than, for ex-
ample, string edit distance. At the same time, it still works for the trivial cases,
as common words will generate similar distributional representations. The main
strength of DisMatch (and its distributional semantic relatedness component) is
its ability of finding non-trivial mappings, which seems to be confirmed by the
number of unique correct matches generated by the system (and the unique-to-
total mappings ratio).
    Nonetheless, the structural matching strategy still seems to be an important
component of the system, as the relatedness matcher itself will, for example,
generate high confidence matches for inputs, such as ’X syndrome’ and ’Y syn-
drome’, if X and Y are very rare in the background corpus. The importance
of the structural matching step seems to be consistent with the performance
gap between HP-MP (where the structural matcher worked) and DOID-ORDO
(where it did not work properly) cases.
    We believe that DisMatch could be improved substantially through improving
the relatedness-structure matching combination, i.e. by employing a better suited
structural matcher. Furthermore, our current structural matching strategy relied
solely on strictly taxonomic relationships, which is not always enough (i.e. in the
case of the OrphaNet ontology).
    Furthermore, semantic relatedness module generates candidate mappings
that are not necessarily ’equivalent’, as the measure does not distinguish between
the possible relationship types. It is worth considering adding an additional ’pre-
diction’ module to provide a classification output of the relationship type of the
mappings.
    Moreover, when it comes to improving the performance of the relatedness
module itself, it seems that the measure provides more accurate results for


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shorter input texts. This points to two possible improvements: (a) in finding
a better suited compositional approach for the lexical relatedness measure, or
(b) in using shorter inputs (possibly through synonym properties of the ontolo-
gies to be aligned).


4   Conclusions

The results obtained with the DisMatch system show enough promise to continue
the experiments with corpus-based distributional relatedness measures applied
to the problem of ontology alignment. We believe, that our focus should now
be on providing an optimal set of additional components around the relatedness
measure. In addition, we expect that tuning of the filtering parameters will lead
the proposed system to reach higher precision with respect to silver standards.


Acknowledgments
This work has been partially funded by Grants TIN2014-58304-R (Spanish Min-
istry of Education and Science) and P11-TIC-7529 (Innovation, Science and
Enterprise Ministry of the regional government of the Junta de Andalucı́a) and
P12-TIC-1519 (Plan Andaluz de Investigación, Desarrollo e Innovación). José
Garı́a-Nieto is recipient of a Post-Doctoral fellowship of “Captación de Talento
para la Investigación” at Universidad de Málaga.


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