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Arjen de Vries (arjen) - 11 years ago 2014-06-12 05:02:12
arjen.de.vries@cwi.nl
hopefully fixed the conflicts

Merge branch 'master' of https://scm.cwi.nl/IA/cikm-paper

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mypaper-final.tex
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@@ -65,7 +65,7 @@
 
% without further effort on your part as the last section in
 
% the body of your article BEFORE References or any Appendices.
 
 
\numberofauthors{2} %  in this sample file, there are a *total*
 
\numberofauthors{8} %  in this sample file, there are a *total*
 
% of EIGHT authors. SIX appear on the 'first-page' (for formatting
 
% reasons) and the remaining two appear in the \additionalauthors section.
 
%
 
@@ -150,12 +150,7 @@ In 2012, the Text REtrieval Conferences (TREC) introduced the Knowledge Base Acc
 
   
 
 Filtering is a crucial step in CCR for selecting a potentially
 
 relevant set of working documents for subsequent steps of the
 
 pipeline out of a big collection of stream documents. The TREC
 
 Filtering track defines filtering as a ``system that sifts through
 
 stream of incoming information to find documents that are relevant to
 
 a set of user needs represented by profiles''
 
 \cite{robertson2002trec}. 
 
In the specific setting of CCR, these profiles are
 
 pipeline out of a big collection of stream documents. Filtering  sifts  an incoming information for information relevant to user profiles \cite{robertson2002trec}. In the specific setting of CCR, these profiles are
 
represented by persistent KB entities (Wikipedia pages or Twitter
 
users, in the TREC scenario).
 
 
 
@@ -180,7 +175,7 @@ Also, different
 
approaches use different entity profiles for filtering, varying from
 
using just the KB entities' canonical names to looking up DBpedia name
 
variants, and from using the bold words in the first paragraph of the Wikipedia
 
entities page to using anchor texts from other Wikipedia pages, and from
 
entities' page to using anchor texts from other Wikipedia pages, and from
 
using the exact name as given to WordNet derived synonyms. The type of entities
 
(Wikipedia or Twitter) and the category of documents in which they
 
occur (news, blogs, or tweets) cause further variations.
 
@@ -210,11 +205,10 @@ compromising precision, describing and classifying relevant documents
 
that are not amenable to filtering , and estimating the upper-bound
 
of recall on entity-based filtering.
 
 
The rest of the paper is is organized as follows: 
 
The rest of the paper  is organized as follows. Section \ref{sec:desc} describes the dataset and section \ref{sec:fil} defines the task. In section  \ref{sec:lit}, we discuss related litrature folowed by a discussion of our method in \ref{sec:mthd}. Following that,  we present the experimental resulsy in \ref{sec:expr}, and discuss and analyze them in \ref{sec:analysis}. Towards the end, we discuss the impact of filtering choices on classification in section \ref{sec:impact}, examine and categorize unfilterable docuemnts in section \ref{sec:unfil}. Finally, we present our conclusions in \ref{}{sec:conc}.
 
 
\textbf{TODO!!}
 
 
 \section{Data Description}
 
 \section{Data Description}\label{sec:desc}
 
We base this analysis on the TREC-KBA 2013 dataset%
 
\footnote{\url{http://trec-kba.org/trec-kba-2013.shtml}}
 
that consists of three main parts: a time-stamped stream corpus, a set of
 
@@ -307,7 +301,7 @@ relevant annotations are social (social and weblog) (63.13\%). News
 
93\% of all annotations.  The rest make up about 7\% and are all
 
grouped as others.
 
 
 \section{Stream Filtering}
 
 \section{Stream Filtering}\label{sec:fil}
 
 
 
 The TREC Filtering track defines filtering as a ``system that sifts
 
 through stream of incoming information to find documents that are
 
@@ -368,7 +362,7 @@ pipeline performance we use the official TREC KBA evaluation metric
 
and scripts \cite{frank2013stream} to report max-F, the maximum
 
F-score obtained over all relevance cut-offs.
 
 
\section{Literature Review}
 
\section{Literature Review} \label{sec:lit}
 
There has been a great deal of interest  as of late on entity-based filtering and ranking. One manifestation of that is the introduction of TREC KBA in 2012. Following that, there have been a number of research works done on the topic \cite{frank2012building, ceccarelli2013learning, taneva2013gem, wang2013bit, balog2013multi}.  These works are based on KBA 2012 task and dataset  and they address the whole problem of entity filtering and ranking.  TREC KBA continued in 2013, but the task underwent some changes. The main change between  the 2012 and 2013 are in the number of entities, the type of entities, the corpus and the relevance rankings.
 
 
The number of entities increased from 29 to 141, and it included 20 Twitter entities. The TREC KBA 2012 corpus is 1.9TB after xz-compression and has  400M documents. By contrast, the KBA 2013 corpus is 6.45 after XZ-compression and GPG encryption. A version with all-non English documented removed  is 4.5 TB and consists of 1 Billion documents. The 2013 corpus subsumed the 2012 corpus and added others from spinn3r, namely main-stream news, forum, arxiv, classified, reviews and meme-tracker.  A more important difference is, however, a change in the definitions of relevance ratings vital and relevant. While in KBA 2012, a document was judged vital if it has citation-worthy content for a given entity, in 2013 it must have the freshliness, that is the content must trigger an editing of the given entity's KB entry. 
 
@@ -379,7 +373,7 @@ All of the studies used filtering as their first step to generate a smaller set
 
 
Moreover, there has not been a chance to study at this scale and/or a study into what type of documents defy filtering and why? In this paper, we conduct a manual examination of the documents that are missing and classify them into different categories. We also estimate the general upper bound of recall using the different entities profiles and choose the best profile that results in an increased over all performance as measured by F-measure. 
 
 
\section{Method}
 
\section{Method}\label{sec:mthd}
 
All analyses in this paper are carried out on the documents that have
 
relevance assessments associated to them. For this purpose, we
 
extracted those documents from the big corpus. We experiment with all
 
@@ -508,7 +502,7 @@ these, 24162 unique document-entity pairs are vital (9521) or relevant
 
 
 
 
 
\section{Experiments and Results}
 
\section{Experiments and Results}\label{sec:expr}
 
 We conducted experiments to study  the effect of cleansing, different entity profiles, types of entities, category of documents, relevance ranks (vital or relevant), and the impact on classification.  In the following subsections, we present the results in different categories, and describe them.
 
 
 
 \subsection{Cleansing: raw or cleansed}
 
@@ -714,7 +708,7 @@ entities, and 79.5\% on Twitter entities.
 
Section \ref{sec:analysis} discusses the most plausible explanations for these findings.
 
%% TODO: PERHAPS SUMMARY OF DISCUSSION HERE
 
 
\section{Impact on classification}
 
\section{Impact on classification}\label{sec:impact}
 
In the overall experimental setup, classification, ranking, and
 
evaluation are kept constant. Following \cite{balog2013multi}
 
settings, we use
 
@@ -988,7 +982,9 @@ Twitter entities, the name-variant partial profile achieves the
 
highest F-score across all entity profiles and types of corpus.
 
 
 
Cleansing impacts Twitter
 
There are 3 interesting observations: 
 
 
1) cleansing impacts Twitter
 
entities and relevant documents.  This  is validated by the
 
observation that recall  gains in Twitter entities and the relevant
 
categories in the raw corpus also translate into overall performance
 
@@ -1040,79 +1036,25 @@ step.
 
 
 
 
The deltas between entity profiles, relevance ratings, and document
 
categories reveal four differences between Wikipedia and Twitter
 
entities. 1) For Wikipedia entities, the difference between canonical
 
partial and canonical is higher(16.1\%) than between name-variant
 
partial and  name-variant(8.3\%).  This can be explained by
 
saturation. This is to mean that documents have already been extracted
 
by  name-variants and thus using their partials does not bring in many
 
new relevant documents.  2) Twitter entities are mentioned by
 
name-variant or name-variant partial and that is seen in the high
 
recall achieved  compared to the low recall achieved by canonical(or
 
their partial). This indicates that documents (specially news and
 
others) almost never use user names to refer to Twitter
 
entities. Name-variant partials are the best entity profiles for
 
Twitter entities. 3) However, comparatively speaking, social documents
 
refer to Twitter entities by their user names than news and others
 
suggesting a difference in adherence to standard in names and naming. 
 
4) Wikipedia entities achieve higher recall and higher overall performance. 
 

	
 
The high recall and subsequent higher overall performance of Wikipedia
 
entities can  be due to two reasons. 1) Wikipedia entities are
 
relatively well described than Twitter entities. The fact that we can
 
retrieve different name variants from DBpedia is a measure of
 
relatively rich description. Rich description plays a role in both
 
filtering and computation of features such as similarity measures in
 
later stages of the pipeline.   By contrast, we have only two names
 
for Twitter entities: their user names and their display names which
 
we collect from their Twitter pages. 2) There is not DBpedia-like
 
resource for Twitter entities from which alternative names cane be
 
collected.
 
 
In the experimental results, we also observed that recall scores in
 
the vital category are higher than in the relevant category. This
 
observation  confirms one commonly held assumption:(frequency) mention
 
is related to relevance.  this is the assumption why term frequency is
 
used an indicator of document relevance in many information retrieval
 
systems. The more  a document mentions an entity explicitly by name,
 
the more likely the document is vital to the entity.
 

	
 
Across document categories, we observe a pattern in recall of
 
documents from the ``others'' category, followed by ``news'', and then
 
by ``social''. The social documents relevant to an entity are the
 
hardest to retrieve. This can be explained by the fact that social
 
documents (tweets and  blogs) are more likely to point to a resource
 
where the entity is mentioned, mention the entities with some short
 
abbreviation, or talk without mentioning the entities, but with some
 
context in mind. By contrast news documents mention the entities they
 
talk about using the common name variants more than social documents
 
do. However, the greater difference in percentage recall between the
 
different entity profiles in the news category indicates news refer to
 
a given entity with different names, rather than by one standard
 
name. By contrast others show least variation in referring to
 
news. Social documents falls in between the two.  The deltas, for
 
Wikipedia entities, between canonical partials and canonicals,  and
 
name-variants and canonicals are high, an indication that canonical
 
partials
 
and name-variants bring in new relevant documents that can not be
 
retrieved by canonicals. The rest of the two deltas are very small,
 
suggesting that partial names of name variants do not bring in new
 
relevant documents.
 
 
% Was: \section{Unfilterable documents}
 
\section{Missing vital-relevant documents \label{miss}}
 
 
 The use of name-variant partial for filtering is an aggressive
 
 attempt to retrieve as many relevant documents as possible at the
 
 cost of retrieving irrelevant documents. However, we still miss about
 
 2363(10\%) of the vital-relevant documents.  Why are these documents
 
 never retrieved? If they are not mentioned by partial names of name
 
 variants, what are they mentioned by? Table \ref{tab:miss} summarizes
 
 the number of documents that we miss with respect to cleansed and raw
 
 corpus.  The upper part shows the number of documents missing from
 
 cleansed and raw versions of the corpus. The lower part of the table
 
 shows the intersections and exclusions in each corpus.
 
The deltas between entity profiles, relevance ratings, and document categories reveal four differences between Wikipedia and Twitter entities. 1) For Wikipedia entities, the difference between canonical partial and canonical is higher(16.1\%) than between name-variant partial and  name-variant(8.3\%).  This can be explained by saturation. This is to mean that documents have already been extracted by  name-variants and thus using their partials does not bring in many new relevant documents.  2) Twitter entities are mentioned by name-variant or name-variant partial and that is seen in the high recall achieved  compared to the low recall achieved by canonical(or their partial). This indicates that documents (specially news and others) almost never use user names to refer to Twitter entities. Name-variant partials are the best entity profiles for Twitter entities. 3) However, comparatively speaking, social documents refer to Twitter entities by their user names than news and others suggesting a difference in 
 
adherence to standard in names and naming. 4) Wikipedia entities achieve higher recall and higher overall performance. 
 
 
The high recall and subsequent higher overall performance of Wikipedia entities can  be due to two reasons. 1) Wikipedia entities are relatively well described than Twitter entities. The fact that we can retrieve different name variants from DBpedia is a measure of relatively rich description. Rich description plays a role in both filtering and computation of features such as similarity measures in later stages of the pipeline.   By contrast, we have only two names for Twitter entities: their user names and their display names which we collect from their Twitter pages. 2) There is not DBpedia-like resource for Twitter entities from which alternative names cane be collected.   
 
 
 
In the experimental results, we also observed that recall scores in the vital category are higher than in the relevant category. This observation  confirms one commonly held assumption:(frequency) mention is related to relevance.  this is the assumption why term frequency is used an indicator of document relevance in many information retrieval systems. The more  a document mentions an entity explicitly by name, the more likely the document is vital to the entity.
 
 
Across document categories, we observe a pattern in recall of others, followed by news, and then by social. Social documents are the hardest to retrieve. This can be explained by the fact that social documents (tweets and  blogs) are more likely to point to a resource where the entity is mentioned, mention the entities with some short abbreviation, or talk without mentioning the entities, but with some context in mind. By contrast news documents mention the entities they talk about using the common name variants more than social documents do. However, the greater difference in percentage recall between the different entity profiles in the news category indicates news refer to a given entity with different names, rather than by one standard name. By contrast others show least variation in referring to news. Social documents falls in between the two.  The deltas, for Wikipedia entities, between canonical partials and canonicals,  and name-variants and canonicals are high, an indication that canonical partials 
 
and name-variants bring in new relevant documents that can not be retrieved by canonicals. The rest of the two deltas are very small,  suggesting that partial names of name variants do not bring in new relevant documents. 
 
 
 
\section{Unfilterable documents}\label{sec:unfil}
 
 
\subsection{Missing vital-relevant documents \label{miss}}
 
 
% 
 
 
 The use of name-variant partial for filtering is an aggressive attempt to retrieve as many relevant documents as possible at the cost of retrieving irrelevant documents. However, we still miss about  2363(10\%) of the vital-relevant documents.  Why are these documents missed? If they are not mentioned by partial names of name variants, what are they mentioned by? Table \ref{tab:miss} shows the documents that we miss with respect to cleansed and raw corpus.  The upper part shows the number of documents missing from cleansed and raw versions of the corpus. The lower part of the table shows the intersections and exclusions in each corpus.  
 
 
\begin{table}
 
\caption{The number of documents missing  from raw and cleansed extractions. }
 
@@ -1137,58 +1079,24 @@ Raw & 276 & 4951 & 5227 \\
 
\label{tab:miss}
 
\end{table}
 
 
One would usually have assumed that the set of document-entity pairs extracted
 
from the cleansed part of the corpus would form a sub-set of those
 
extracted from the raw corpus. Suprisingly, we found this not to be
 
the case: 217 unique entity-document pairs are retrieved from the
 
cleansed corpus, but not from the raw one, out of which 57 have been
 
judged as vital. Similarly, 3081 document-entity pairs only occur in
 
the raw corpus, with 1065 vital documents among these. Examining the content of these
 
documents reveals that these ommissions are easily explained by
 
missing text in the corresponding documents.  All the documents that we miss from the raw
 
corpus are social, like tweets, blogs and posts
 
from other social media. To meet the format of the raw data (binary
 
byte array), some of these must have been converted later, after
 
collection (as a cleansed version has been produced), but affected by
 
some processing error. For the documents that we miss from the
 
cleansed corpus, a part of their (or even the
 
entire) content is lost during the cleansing process (the removal of
 
HTML tags and non-English documents).  In both cases the mention of
 
the entity happened to be on the part of the text that is cut out
 
during transformation. 
 

	
 
The more intriguing set of relevance judgments are those that we miss
 
from both raw and cleansed extractions, concerning 2146 unique
 
document-entity pairs, 219 of them assessed as vital to the entity.
 
The number of entities in the missed vital annotations is 28
 
Wikipedia and 7 Twitter, making a total of 35. The great majority
 
(86.7\%) of these documents are social. This suggests that social
 
media sources
 
(tweets and blogs) may discuss these entities without mentioning
 
them explicitly by name, more than in news and other types of
 
documents. (This is, of course, in line with intuition.)
 
One would  assume that  the set of document-entity pairs extracted from cleansed are a sub-set of those   that are extracted from the raw corpus. We find that that is not the case. There are 217  unique entity-document pairs that are retrieved from the cleansed corpus, but not from the raw. 57 of them are vital.    Similarly,  there are  3081 document-entity pairs that are missing  from cleansed, but are present in  raw. 1065 of them are vital.  Examining the content of the documents reveals that it is due to a missing part of text from a corresponding document.  All the documents that we miss from the raw corpus are social. These are documents such as tweets and blogs, posts from other social media. To meet the format of the raw data (binary byte array), some of them must have been converted later, after collection and on the way lost a part or the entire content. It is similar for the documents that we miss from cleansed: a part or the entire content  is lost in during the cleansing process (the removal of 
 
HTML tags and non-English documents).  In both cases the mention of the entity happened to be on the part of the text that is cut out during transformation. 
 
 
 
 
 The interesting set  of relevance judgments are those that  we miss from both raw and cleansed extractions. These are 2146 unique document-entity pairs, 219 of them are with vital relevance judgments.   The total number of entities in the missed vital annotations is  28 Wikipedia and 7  Twitter, making a total of 35. The  great majority (86.7\%) of the documents are social. This suggests that social (tweets and blogs) can talk about the entities without mentioning  them by name more than news and others do. This is, of course, inline with intuition. 
 
   
 
 
 
%%%%%%%%%%%%%%%%%%%%%%
 
 
We  observed  that among the missing documents, different document
 
ids can have the same content, and be judged multiple times for a
 
given entity.
 
%In the vital annotation, there are 88 news, and 409
 
%weblog. 
 
Avoiding duplicates, we randomly selected 35 documents, one for each
 
entity.   The documents are 13 news and  22  social. Here below we
 
have classified the situation under which a document can be vital for
 
an entity without mentioning the entities with the different entity
 
profiles we used for filtering.
 
We observed that there are vital-relevant documents that we miss from raw only, and similarly from cleansed only. The reason for this is transformation from one format to another. The most interesting documents are those that we miss from both raw and cleansed corpus. We first identified the number of KB entities who have a vital relevance judgment and  whose documents can not be retrieved (they were 35 in total) and conducted a manual examination into their content to find out why they are missing. 
 
 
 
 
 
 We  observed  that among the missing documents, different document ids can have the same content, and be judged multiple times for a given entity.  %In the vital annotation, there are 88 news, and 409 weblog. 
 
 Avoiding duplicates, we randomly selected 35 documents, one for each entity.   The documents are 13 news and  22  social. Here below we have classified the situation under which a document can be vital for an entity without mentioning the entities with the different entity  profiles we used for filtering. 
 
 
\paragraph*{Outgoing link mentions} A post (tweet) with an outgoing link which mentions the entity.
 
\paragraph*{Event place - Event} A document that talks about an event
 
is vital to the location entity where it takes place.  For example
 
Maha Music Festival takes place in Lewis and Clark\_Landing, and a
 
document talking about the festival is vital for the park. There are
 
also cases where an event's address places the event in a park, and due
 
to that the document becomes vital to the park. 
 
\paragraph*{Event place - Event} A document that talks about an event is vital to the location entity where it takes place.  For example Maha Music Festival takes place in Lewis and Clark\_Landing, and a document talking about the festival is vital for the park. There are also cases where an event's address places the event in a park and due to that the document becomes vital to the park. This is basically being mentioned by address which belongs to alarger space. 
 
\paragraph*{Entity -related entity} A document about an important figure such as artist, athlete  can be vital to another. This is specially true if the two are contending for the same title, one has snatched a title, or award from the other. 
 
\paragraph*{Organization - main activity} A document that talks about about an area on which the company is active is vital for the organization. For example, Atacocha is a mining company  and a news item on mining waste was annotated vital. 
 
\paragraph*{Entity - group} If an entity belongs to a certain group (class),  a news item about the group can be vital for the individual members. FrankandOak is  named innovative company and a news item that talks about the group  of innovative companies is relevant for a  it. Other examples are: a  big event  of which an entity is related such an Film awards for actors. 
 
@@ -1202,7 +1110,7 @@ to that the document becomes vital to the park.
 
 
 
 
\section{Conclusions}
 
\section{Conclusions} \label{sec:conc}
 
In this paper, we examined the filtering stage of the entity-centric stream filtering and ranking  by holding the later stages of fixed. In particular, we studied the cleansing step, different entity profiles, type of entities(Wikipedia or Twitter), categories of documents(news, social, or others) and the relevance ratings. We attempted to address the following research questions: 1) does cleansing affect filtering and subsequent performance? 2) what is the most effective way of entity profiling? 3) is filtering different for Wikipedia and Twitter entities? 4) are some type of documents easily filterable and others not? 5) does a gain in recall at filtering step translate to a gain in F-measure at the end of the pipeline? and 6) what are the circumstances under which vital documents can not be retrieved? 
 
 
Cleansing does remove parts or entire contents of documents making them irretrievable. However, because of the introduction of false positives, recall gains by  raw corpus and some  richer entity profiles do not necessarily translate to overall performance gain. The results conclusion on this is mixed in the sense that cleansing helps improve the recall on vital documents and Wikipedia entities, but reduces the recall on Twitter entities and the relative category of relevance ranking. Vital and relevant documents show a difference in retrieval nonperformance documents are easier to filter than relevant.  
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