The Google-like query interface
The query interface of SemSearch extends traditional keyword search
by allowing the explicit speciﬁcation of i) the queried subject and ii)
nation of keywords. By the term subject, the user can explicitly tell
engine the expected type of the search results. For example, when the
iﬁes the keyword “news” as the subject keyword, he or she expects the
results to be the instances of the class entity that matches against the
“news”. By allowing the speciﬁcation of how to combine multiple
search engine provides end users a simple way of expressing complex
SemSearch uses three heuristic operators to support the speciﬁcation of
queries. The ﬁrst one is the symbol “:”, which supports the speciﬁcation
subjects. The second one is the word “and”, which indicates that all the
connected by the word are required to have connections with the search
The last one is the word “or ”, which supports the speciﬁcation of
keywords. Thus, a user query in SemSearch looks like “subject:keyword1
keyword2 and/or keyword3 ...”.
With this query syntax, the example of “news about phd students” can be
easily speciﬁed as news:phd students, where the term news is the query
and the term phd students is a required keyword.
More complex queries in whichSemSearch: A Search Engine for the Semantic
multiple keywords (except the subject keyword) are involved also can be
speciﬁed. For example, when querying for projects in which both Enrico
John participate, the query can be speciﬁed as project:Enrico and John.
user wants to know all the projects that Enrico or John are involved in,
query is project:Enrico or John.
In order to satisfy a query, each of the required keywords (please note
subject is a special required keyword) must be satisﬁed, which means
search results must be semantically related to each of the required
the case when there are optional keywords, one of the optional keywords
The SemSearch query interface provides a simple, ﬂexible, and powerful
proach for specifying user queries in semantic search. First, it
problem of knowledge overhead suﬀered in formal query fronted search
and form-based semantic search engines, as it does not require end users
familiar with any particular ontology, semantic data, or any special
guage. Second, the query interface provides a more ﬂexible way of
queries than the interface presented by form-based search engines.
does not conﬁne users to any pre-deﬁned query subjects and values.
contrast with current semantic-based keyword search engines which only
one keyword as input, this query interface supports the speciﬁcation of
queries in the format of specifying multiple keywords and the expected
results. Finally, this query interface is simpler than question
answering tools as
the search engine does not need to spend time calculating which of the
are in a user’s query.
In this paper, we focus on the user queries in which there are at least
keywords involved, in order to better explain the distinctive features
search engine. Regarding those queries that only comprise one keyword,
search engine develops an approach that is similar to the ones used in
in to ﬁnd instances that are closely related to the semantic entity