9
R: A unique approach for exploring news archives Abram Handler College of Information and Computer Sciences University of Massachuses Amherst 140 Governors Dr. Amherst, Massachuses 01003 [email protected] Brendan O’Connor College of Information and Computer Sciences University of Massachuses Amherst 140 Governors Dr. Amherst, Massachuses 01003 [email protected] ABSTRACT News archives are an invaluable primary source for placing current events in historical context. But current search engine tools do a poor job at uncovering broad themes and narratives across docu- ments. We present R: a practical soware system which uses natural language processing (NLP) to help readers, reporters and editors uncover broad stories in news archives. Unlike prior work, R’s design emerged from 18 months of iterative development in consultation with editors and computational journalists. is process lead to a dramatically dierent approach from previous aca- demic systems with similar goals. Our eorts oer a generalizable case study for others building real-world journalism soware using NLP. CCS CONCEPTS Human-centered computing Empirical studies in HCI; KEYWORDS H.5.2. Information Interfaces and Presentation: Graphical user interfaces ACM Reference format: Abram Handler and Brendan O’Connor. 2017. R: A unique approach for exploring news archives. In Proceedings of Data Science + Journalism workshop at KDD, Halifax, Nova Scotia, Canada, August 2017 (DS+J’17), 9 pages. DOI: 10.475/123 4 1 INTRODUCTION News archives oer a rich historical record. But if a reader or journalist wants to learn about a new topic with a traditional search engine, they must enter a query and begin reading or skimming old articles one-by-one, slowly piecing together the intricate web of people, organizations, events, places, topics, concepts and social forces that make up “the news.” We propose R, which began as an aempt to build a useful tool for journalists. With R, a user’s query generates an inter- active timeline, a list of important related subjects, and summary of matching articles—all displayed together as a collection of inter- active linked views (g. 1). Users click and drag along the timeline Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for prot or commercial advantage and that copies bear this notice and the full citation on the rst page. Copyrights for third-party components of this work must be honored. For all other uses, contact the owner/author(s). DS+J’17, Halifax, Nova Scotia, Canada © 2017 Copyright held by the owner/author(s). 123-4567-24-567/08/06. . . $15.00 DOI: 10.475/123 4 to select certain date ranges, automatically regenerating the sum- mary and subject list at interactive speed. e cumulative eect: users can uidly investigate complex news stories as they evolve across time. antitative user testing shows how this system helps users beer understand complex topics from documents and nish a historical sensemaking task 37% faster than with a traditional interface. alitative studies with student journalists also validate the approach. We built the nal version of R following eighteen months of iterative design and development in consultation with reporters and editors. Because the system aimed to help real-world jour- nalists, the soware which emerged from the design process is dramatically dierent from similar academic eorts (§6.3). Specif- ically, R was forced to cope with limitations in the speed, accuracy and interpretability of current natural language process- ing techniques (see §6). We think that understanding and designing around such limitations is vital to successfully using NLP in jour- nalism applications; a topic which, to our knowledge, has not been explored in prior work at the intersection of two elds. 2 THE ROOKIE SYSTEM At any given time, R’s state is dened with the user selection state, a triple (Q, F, T) where: Q is a free text query string (e.g. “Bashar al-Assad”) F is a related subject string (e.g. “30 years”) or is null T is a timespan (e.g. Mar. 2000–Sep. 2000); by default, this is set to the span of publication dates in the corpus. Users rst interact with R by entering a query, Q into a search query bar using a web browser. For example, in g. 2a, a user seeking to understand the roots of the Syrian civil war has entered Q = “Bashar al-Assad”. In response, R renders an interactive time series visualization showing the frequency of matching doc- uments from the corpus (§2.4), a list of subjects in the matching documents (§2.2), called and a textual summary of those documents (§2.3), called . 1 Aer entering Q, the user might notice that “Bashar al-Assad” is mainly mentioned from 1999 onwards. To investigate, they might adjust the time series slider to a spike in early mentions of Bashar al-Assad, T =Mar. 2000–Sep. 2000 (g. 2b). When the user adjusts T to Mar. 2000–Sep. 2000, and change to reect the new timespan (g. 2c). now shows subjects like “TRANSITION IN SYRIA”, 2 1 In this example, the corpus is a collection of New York Times world news articles from 1987 to 2007 that contain the string “Syria”. All of the country-specic examples in this study are subsets of the same New York Times LDC corpus [37]. 2 Formaing from NYT section header style. arXiv:1708.01944v1 [cs.HC] 6 Aug 2017

Rookie: A unique approach for exploring news archives

  • Upload
    others

  • View
    1

  • Download
    0

Embed Size (px)

Citation preview

Page 1: Rookie: A unique approach for exploring news archives

Rookie: A unique approach for exploring news archivesAbram Handler

College of Information and Computer SciencesUniversity of Massachuse�s Amherst

140 Governors Dr.Amherst, Massachuse�s 01003

[email protected]

Brendan O’ConnorCollege of Information and Computer Sciences

University of Massachuse�s Amherst140 Governors Dr.

Amherst, Massachuse�s [email protected]

ABSTRACT

News archives are an invaluable primary source for placing currentevents in historical context. But current search engine tools do apoor job at uncovering broad themes and narratives across docu-ments. We present Rookie: a practical so�ware system which usesnatural language processing (NLP) to help readers, reporters andeditors uncover broad stories in news archives. Unlike prior work,Rookie’s design emerged from 18 months of iterative developmentin consultation with editors and computational journalists. �isprocess lead to a dramatically di�erent approach from previous aca-demic systems with similar goals. Our e�orts o�er a generalizablecase study for others building real-world journalism so�ware usingNLP.

CCS CONCEPTS

•Human-centered computing→ Empirical studies in HCI;

KEYWORDS

H.5.2. Information Interfaces and Presentation: Graphical userinterfacesACM Reference format:

Abram Handler and Brendan O’Connor. 2017. Rookie: A unique approachfor exploring news archives. In Proceedings of Data Science + Journalismworkshop at KDD, Halifax, Nova Scotia, Canada, August 2017 (DS+J’17),9 pages.DOI: 10.475/123 4

1 INTRODUCTION

News archives o�er a rich historical record. But if a reader orjournalist wants to learn about a new topic with a traditional searchengine, they must enter a query and begin reading or skimmingold articles one-by-one, slowly piecing together the intricate webof people, organizations, events, places, topics, concepts and socialforces that make up “the news.”

We propose Rookie, which began as an a�empt to build a usefultool for journalists. With Rookie, a user’s query generates an inter-active timeline, a list of important related subjects, and summaryof matching articles—all displayed together as a collection of inter-active linked views (�g. 1). Users click and drag along the timeline

Permission to make digital or hard copies of part or all of this work for personal orclassroom use is granted without fee provided that copies are not made or distributedfor pro�t or commercial advantage and that copies bear this notice and the full citationon the �rst page. Copyrights for third-party components of this work must be honored.For all other uses, contact the owner/author(s).DS+J’17, Halifax, Nova Scotia, Canada© 2017 Copyright held by the owner/author(s). 123-4567-24-567/08/06. . .$15.00DOI: 10.475/123 4

to select certain date ranges, automatically regenerating the sum-mary and subject list at interactive speed. �e cumulative e�ect:users can �uidly investigate complex news stories as they evolveacross time. �antitative user testing shows how this system helpsusers be�er understand complex topics from documents and �nisha historical sensemaking task 37% faster than with a traditionalinterface. �alitative studies with student journalists also validatethe approach.

We built the �nal version of Rookie following eighteen monthsof iterative design and development in consultation with reportersand editors. Because the system aimed to help real-world jour-nalists, the so�ware which emerged from the design process isdramatically di�erent from similar academic e�orts (§6.3). Specif-ically, Rookie was forced to cope with limitations in the speed,accuracy and interpretability of current natural language process-ing techniques (see §6). We think that understanding and designingaround such limitations is vital to successfully using NLP in jour-nalism applications; a topic which, to our knowledge, has not beenexplored in prior work at the intersection of two �elds.

2 THE ROOKIE SYSTEM

At any given time, Rookie’s state is de�ned with theuser selectionstate, a triple (Q,F,T) where:

• Q is a free text query string (e.g. “Bashar al-Assad”)• F is a related subject string (e.g. “30 years”) or is null• T is a timespan (e.g. Mar. 2000–Sep. 2000); by default, this

is set to the span of publication dates in the corpus.Users �rst interact with Rookie by entering a query, Q into a

search query bar using a web browser. For example, in �g. 2a, a userseeking to understand the roots of the Syrian civil war has enteredQ = “Bashar al-Assad”. In response, Rookie renders an interactivetime series visualization showing the frequency of matching doc-uments from the corpus (§2.4), a list of subjects in the matchingdocuments (§2.2), called subjects-sum and a textual summary ofthose documents (§2.3), called sentence-sum.1

A�er entering Q, the user might notice that “Bashar al-Assad” ismainly mentioned from 1999 onwards. To investigate, they mightadjust the time series slider to a spike in early mentions of Basharal-Assad, T =Mar. 2000–Sep. 2000 (�g. 2b).

When the user adjusts T to Mar. 2000–Sep. 2000, sentence-sumand subjects-sum change to re�ect the new timespan (�g. 2c).subjects-sum now shows subjects like “TRANSITION IN SYRIA”,2

1In this example, the corpus is a collection of New York Times world news articles from1987 to 2007 that contain the string “Syria”. All of the country-speci�c examples inthis study are subsets of the same New York Times LDC corpus [37].2Forma�ing from NYT section header style.

arX

iv:1

708.

0194

4v1

[cs

.HC

] 6

Aug

201

7

Page 2: Rookie: A unique approach for exploring news archives

DS+J’17, August 2017, Halifax, Nova Scotia, Canada Abram Handler and Brendan O’Connor

B C

A

Figure 1: �e Rookie interface running on a corpus of New York Times articles about Haiti. �e user has queried for “United

States.” �e interface features linked visualization and summarization views: (A) an interactive timeline, (B) subjects-sum

showing automatically-generated related subjects, and (C) sentence-sum showing sentence summaries. �e temporal spikes

indicatemajor events such as a 1994 U.S. intervention inHaiti and a 2004military coup. Related subjects include speci�c actors

in some of these events (Jean-Bertrand Aristide, President Clinton) as well as long-running topics (human rights). Users can

click and drag along the timeline to investigate speci�c time periods.

“President Assad”, “eldest son” and “30 years” which are importantto Q during T. (Bashar al-Assad’s father ruled for 30 years).

At this point, the user might explore further by investigating therelated subject, F =“President Assad”—clicking to select. sentence-sum now a�empts to summarize the relationship between Q =“Basharal-Assad” and F =“President Assad” during T =Mar. 2000–Sep. 2000(�g. 2d). For instance, sentence-sum now shows the sentence:“Bashar al-Assad was born on Sept. 11, 1965, in Damascus, the thirdof President Assad’s �ve children.” If the user wants to understandthis sentence in context, they can click the sentence—which opensthe underlying document in a modal dialog.

F and Q are assigned red and blue colors throughout the interface,allowing users to quickly scan for information. Bolding Q and Fgives additional clarity, and helps ensure that Rookie still worksfor colorblind users.

�is example demonstrates how Rookie’s visualization and sum-marization techniques work together to o�er linked views of theunderlying corpus. Linked views (a.k.a. multiple coordinated views)interfaces are common tools for structured information [4, 34, 43]:each view displays the same selected data in a di�erent dimension(e.g. a geographic map of a city which also shows a histogram of

housing costs when a user selects a neighborhood). In Rookie’scase, linked views display di�erent levels of resolution. �e timeseries visualization o�ers a temporal view of query-responsivedocuments, subjects-sum displays a medium-level lexical viewof important subjects within the documents, and sentence-sumdisplays a low-level text view of parts of the underlying docu-ments. �e documents themselves, available by clicking extractedsentences, o�er the most detailed level of zoom. �us Rookie sup-ports the commonly advised visualization pathway: “overview �rst,zoom and �lter, and details on demand” [40].

Note that we use the term summarization to mean selecting ashort text, or sequence of short texts, to represent a body of text.By this de�nition, both subjects-sum and sentence-sum are aform of summarization, as each o�ers a textual representation ofthe corpus—albeit at two di�erent levels of resolution, phrases andsentences. (In the NLP literature, “summarization” usually meansgenerating a sentence or paragraph length summary).

Rookie is a web application implemented in Python.3

3We use the Flask (h�p://�ask.pocoo.org/) framework with a Postgres (h�ps://www.postgresql.org/) database and a React front end (h�ps://facebook.github.io/react). We

Page 3: Rookie: A unique approach for exploring news archives

Rookie: A unique approach for exploring news archives DS+J’17, August 2017, Halifax, Nova Scotia, Canada

Q

timeseries (temporal view)

sentence summary (text view)

F=nullsubject list, (lexical view)

(a) A user enters Q =“Bashar al-Assad” in order to learn more about the

Syrian civil war.

T

(b) �e user zooms in to the blue spike from T =Mar. 2000–Sep. 2000 to

investigate. Rookie updates subjects-sum (�g. c) and sentence-sum

to re�ect T.

Q

F

(c) �e user examines important subjects for Q =“Bashar al-Assad” dur-

ing T =Mar. 2000–Sep. 2000, displayed in subjects-sum. �e user clicks

to investigate F =“President Assad”.

QF

F

T

(d) Rookie now adds mentions of F =“President Assad” to the time se-

ries graph. sentence-sum updates to re�ect Q =“Bashar al-Assad”, F=“President Assad”, T =Mar. 2000–Sep. 2000.

Figure 2: A user investigates “Bashar al-Assad”.

2.1 Linked views

Rookie’suser selection state (Q, F, T) picks out a set of documentsD(Q,F,T), which were published within T, match the query, Q inWhoosh and contain F (if F is not null). �e selection state alsospeci�es a set of sentences S, used to construct a summary (§2.3).�ese documents and sentences are then shown to the user in thelinked views, described individually in the following sections.

2.2 subjects-sum: Lexical view

Rookie uses natural language processing methods to �nd and rec-ommend a list of subjects related to the query Q, during time T.�ese subjects are presented as a concise list of terms—thus o�eringa lexical view of the D(Q,T) selection (�g. 1, bo�om le�).

Rookie’s subject-�nding algorithm works in two stages. Atindex time, Rookie makes a single pass over the corpus to �nd andrecord all phrases which match certain part-of-speech pa�erns.4Speci�cally, Rookie uses the NPFST method from Handler et al.[20] to extract phrases, which Rookie stores in a document–phraseindex. �en, at query time, Rookie uses this index to rank phraseswhich occur in documents responsive to Q—returning top-rankedphrases as subjects for display in the UI.

Speci�cally, each time a user changes Q or T, Rookie identi�esall phrases which occur in the matching documents D(Q,T). Rookiethen assigns each phrase a subject relevance score. Relevance scoresfor each subject s are calculated with qf-idfs = qs ∗ 1

dfswhere

the �rst term, qs (“query frequency”), is a count of how manytimes term s occurs in D(Q,T) and the second term, 1

dfs(“inverse

document frequency”), is the inverse of the number of documentswhich contain s across the corpus. Highly relevant phrases occurfrequently in query-matching documents, D(Q,T), but infrequentlyoverall—similar to TF-IDF and pointwise mutual information [34].Rookie places such high-ranking phrases at the top of subjects-sum.

Note that NP extraction o�en produces split or repeating phrases[20] such as “King Abdullah”, “Abdullah II” and “King AbdullahII”. Rookie uses several simple hand-wri�en string-matching rulesbased on character-level Levenshtein distance and token-level Jac-card similarity to avoid displaying duplicate terms. �ese heuristicscould be improved in future work.

2.3 sentence-sum: Text view

Rookie’s time series visualizations o�er an immediate question:what does Q have to do with F during T? For example, in �g. 1, theuser might wish to learn: what does “United States” have to do withthe phrase “human rights” in articles about Haiti from the early90s? Rookie a�empts to answer using extractive summarization—picking sentences from D(Q,F,T) that can explain the relationship.Unlike in traditional NLP, in Rookie the goal is not just to sum-marize some topic expressed by Q (as in traditional query-focusedsummarization [8]), but to describe what F has to do with Q duringT.

used the open-source search engine Whoosh (h�ps://whoosh.readthedocs.io), whichis broadly similar to Lucene, to �nd documents matching Q.4We only index subjects that occur at least �ve times in the corpus for use in subjectlist generation, though document retrieval for Q utilizes a standard full text index.

Page 4: Rookie: A unique approach for exploring news archives

DS+J’17, August 2017, Halifax, Nova Scotia, Canada Abram Handler and Brendan O’Connor

Rookie also requires that any summary can be produced quicklyenough to support interactive search (see §6). �us, in buildingRookie, we found it useful to require that the client be able togenerate a summary in less than half a second without server com-munication.5 �is principle allowed us to achieve �uid, exploratoryinteractions. �e details of sentence-sum are discussed below.

2.3.1 Summary implementation: server side. A�er Rookie sendsa user query, Q to the server, each query-responsive document inD(Q,F,T) is permi�ed to send exactly one sentence to the client. �issentence is chosen by adding each sentence in the document to atwo-tiered priority queue. �e tier 1 score records if the sentencecontains both Q and F (top priority), Q or F (medium priority)or neither Q nor F (low priority). �e tier 2 score is simply thesentence’s sequential number in the document. (Sentences thatcome earlier in the document get higher priority). Rookie sendsthe �rst sentence in each document’s queue to the server, alongwith its publication date, sentence number and tier 1 score. We useS to denote the set of sentences passed to the server.

Figure 3: A baseline interface “IR” interface for ex-

ploring news archives, similar to the search function-

ality found on many news websites. Users enter a (Q,T)pair query and the system returns a list of document–

snippet pairs. We compare Rookie to this interface.

2.3.2 Summary implementation: client side. Rookie seeks tohelp explain what happened during a particular timespan, T. Sowhere traditional summarization seeks topical diversity [8], Rookieaims for temporal diversity. It achieves this diversity by sam-pling sentences with probability in proportion to the count of eachmonthly bin. For instance, if S contains 1000 sentences and 100 ofthem come from, say, March of 1993, then there ought to be a onein ten chance that a sentence from March 1993 is included in thesummary.

In choosing sentences for the summary, Rookie will �rst pickrandomly from among sentences containing Q and F, then pickrandomly from among sentences that contain Q or F and, �nally,pick randomly from sentences containing from neither Q nor F.

Rookie draws sentences, one-by-one, until each sentence fromS is selected and placed into a list. Rookie allows users to pagethrough this list (�g. 1)—starting from highest-ranked and movingtowards lowest-ranked.5Half a second is a rough rule of thumb for acceptable latency in interactive systems,informed by work from both Nielsen [33] and Liu and Heer [27].

2.4 Interactive time series: Temporal view

Rookie’s time series visualization is a standard line graph showingbothD(Q) andD(Q,F) across the time variable. �e y-axis representscounts of documents and the x-axis represents time. For instance,in �gure 1, the blue line shows counts of documents which matchQ =“United States”. A small copy of the time series graph for eachsubject is shown in the subject list (�g. 1). �ese small graphs(“sparklines”) give cues about a subject’s importance at di�erencetimes in a corpus—even if the subject is not selected.

�e time series graph allows the user to specify a desired timerange T. Users can select particular areas of the time series graphby clicking and dragging a timebox [24] to create specialized sum-maries of certain time periods. If the user holds down their mouse,clicks the grey rectangle, and slides the mouse across the time-line, the user state changes to re�ect the new T. subjects-sum andsentence-sum show the evolving relationship through time.

3 EVALUATION

We evaluate Rookie using several established practices for evaluat-ing exploratory search [46][45] including (1) surveys and question-naires to measure user experience and (2) quantitative measure-ments of human performance in completing a search task.6

For each evaluation, we compared Rookie to a traditional searchengine, the baseline tool for answering any question from a collec-tion of documents.

Traditional information retrieval (IR) systems return a rankedlist of document–snippet pairs in response to a user’s textual query.Users read or skim these snippets and documents until they be�erunderstand some aspect of the corpus—possibly re-querying fornew documents during the search. We implemented the IR baselineusing Whoosh.7 Because Rookie allows limiting documents bydate, we also added a frequently-downloaded datepicker widget8

so that IR users can limit results to date ranges.We compared to a traditional search engine for a number of

reasons: users are familiar with Google (but not with alternatives),there are few robust implementations of text analytics researchsystems available and previous work rarely compares to traditionalsearch, which we believe is a robust and powerful baseline.

4 IN-PERSON GROUP EVALUATION

While building Rookie, we solicited ongoing feedback from work-ing journalists. Once we were con�dent in the �nal design, weconducted a larger and more formal user test with 15 undergradu-ate journalism students. Undergraduate journalism students are agood choice for a user group, as Rookie is built for reporters and

6All studies were approved by IRB.7Like other traditional search engines, Whoosh creates small snippets which highlightportions of each query-responsive document, boldfacing matching unigrams fromthe query. We tuned Whoosh snippets by adjusting the top and surround parametersto help the IR system fairly compete with Rookie, which displays whole sentences.Top controls how many “…”-delimited fragments Whoosh returns for each documentresult, while surround is the maximum number of characters around each highlightedtext fragment. By default, Whoosh sets surround=20, but we found that this made forchoppy, confusing snippets, so we adjusted it to 50. We then did a grid search overpossible values of the top parameter—seeking the value that minimized the averageabsolute di�erence in the number of characters shown for each snippet betweenRookie versus Whoosh, arriving at top=2. All other Whoosh parameters were set todefault values.8h�ps://www.npmjs.com/package/react-datepicker

Page 5: Rookie: A unique approach for exploring news archives

Rookie: A unique approach for exploring news archives DS+J’17, August 2017, Halifax, Nova Scotia, Canada

updates summary

dragging mouse

Figure 4: Rookie’s summaries and time series o�er linked views of the corpus. �e sentence-sum panel updates in less

than half a second, so users can drag a cursor across the timeline to read about unfolding events. In this example, as the

user drags the rectangle to the right, they read about the 1991 coup that removed Bertrand Aristide from power—and then

his return several years later with American support.

readers learning about new topics. (An additional evaluation withprofessional journalists would have improved our study, however,their time is very limited).

During the study, we loaded with a corpus of 5496 articles fromthe New York Times from 1987 to 2007 which mentioned the country“Syria”. A�er a short tutorial demo, we presented the users with aexploratory search prompt: “Imagine you just got your �rst job asa fact checker and production assistant on a world news desk. Yourorganization frequently covers the civil war in Syria. Use Rookieto be�er understand the roots of the Syrian civil war so that youcan begin contributing at your new job”.

We gave users twenty minutes to try Rookie using this prompt;then presented a questionnaire about their subjective experience.We did not to tell users about the design intentions behind Rookie.We synthesize answers to each question below.

Q1: Did you enjoy using Rookie? What was good about

it? Or bad about it?

Users overwhelmingly reported that they “really enjoyed usingthis tool” and found it useful “extremely useful in doing research”.One user said: “It made me feel like I could �nd things that may beburied on a more generic search engine”. Another said: “It makes a�uid way to search through a lot of information quickly”.

Q2 “Howdoyou think something like [Rookie] couldhelp

journalists?”

Many users reported that Rookie could be helpful for journalistsor other researchers starting to learn about a new topic, whichwas our intention in designing Rookie. One wrote: “As journalists,it’s important to have a large-view grasp of a story before writingabout it. �e system could be helpful in providing both a snapshotand an ability to then dive deeper into your story”.

Q3 “WhenwouldRookie be better thanusing a traditional

search engine? When would it be worse?”

At the end of the user study, students tried researching the sametopic with a traditional search engine loaded with the same corpus.We asked which tool would be be�er and when. Many mentionedthat Rookie would be superior if you were starting out researchinga new topic—but that a traditional search engine would be superiorif you already had a clear search need. As one student wrote inpraising Rookie: “If you aren’t … familiar about the history of thetopic you probably want to build some context �rst”.

5 TASK COMPLETION EVALUATION

5.1 Historical sensemaking task

Gary Marchionini [29] distinguishes between simple fact-�ndingtasks and exploratory search—the la�er involves activities likecomprehension, interpretation and synthesis. �ese activities aredi�cult to measure, but a simple and direct way to test how wellan exploratory system supports them is to record how long it takesa person to accomplish a sensemaking task which requires thesebehaviors. �is method, sometimes called measuring “task time,”[46] can be used in conjunction with precision and recall measures[35].9

We thus measured how long it takes users to correctly answer thesame complex, non-factoid research question when using Rookieand the IR system. �e question asks a question about the mod-erately complex historical relationship between the United Statesand the Haitian political �gure Jean-Bertrand Aristide. We askedusers to pick the correct answer from among these four: (1) �eUnited States has been a longtime opponent of the Haitian PresidentJean-Bertrand Aristide. (2) �e United States has been a longtimeally of the Haitian President Jean-Bertrand Aristide. (3) �e United

9As White et. al note (chapter 5), exploratory search activities are complex, so ideallyevaluations would also measure depth of learning and understanding. But task time isa good place to start, as they point out.

Page 6: Rookie: A unique approach for exploring news archives

DS+J’17, August 2017, Halifax, Nova Scotia, Canada Abram Handler and Brendan O’Connor

States was initially an ally of Bertrand Aristide – but then stoppedsupporting him. (4) �e US government was initially an opponentof Bertrand Aristide – but then started supporting him.

�e third answer is broadly correct, within the timespan ofthe corpus: the Clinton administration used US troops to restoreBertrand Aristide’s democratically-elected government following acoup in the mid 1990s. �en, ten years later, the Bush administrationdid not support Aristide during a later coup.

Users were asked to answer this question by searching for in-formation New York Times articles which mention “Haiti.” Withinthis corpus, articles exist describing both of these key events inthis historical relationship, but there does not appear to be a com-plete narrative summary of this history. Users have to sort through,comprehend, and synthesize many pieces of information acrossmultiple articles until they know the correct answer. �e task tookup to 21 minutes to complete (36 seconds minimum, 1261 maxi-mum) and was fairly di�cult: only 52% IR users and 54% Rookieusers answered correctly.

Rookie’s evaluation simulates a practical task that a journalistmight undertake in learning about a new subject: either to write an“explainer” piece10 or to research the historical context for currentevents.

5.2 Experiment design

We employed a between-subjects design with U.S. users from Ama-zon Mechanical Turk—placing ��y workers into a Rookie groupand ��y workers into an IR group, and comparing their task com-pletion times and other behaviors. Turkers had a maximum of30 minutes to complete the task, much more than the roughly 15minutes required.11 We limited our study to U.S.-based users.

For each group, the study began with a few short screeningquestions—checking to make sure that workers had their volumeturned on and were using a laptop or desktop (this version ofRookie is designed for these modalities). Rookie users also prac-ticed interpreting a timeseries graph by explaining why mentionsof Afghanistan might have spiked in the New York Times in 2001and 2002. Each group then watched a short video explaining theirinterface and task.

During iterative prototyping (§6), we observed that it takes afew minutes to learn to use Rookie. �us the �nal preliminaryphase for the Rookie group was a practice session to learn theRookie interface on a di�erent corpus of articles mentioning “Cuba”.During this tutorial, users practiced manipulating T to select T=1994–1995 and then answered a question about the U.S and FidelCastro during this time period. A�er this session was complete,users then were given the main task with the Haiti corpus. �ishelped ensure the main task was measuring how long it took usersto �nd answers using Rookie, as opposed to learning how to use it.IR users did not practice using their interface.

Users then a�empted to answer the question using Rookie orIR. In each case, users saw the question and answers on a panelon their screen as they completed their work. To be�er constrainthe task, we presented each group of users with interfaces alreadyloaded with a useful pre-�lled query, rather than relying on users to10e.g. h�p://www.vox.com/2015/9/14/9319293/syrian-refugees-civil-war11Amazon suggests giving workers a generous maximum time limit so that they donot feel rushed

think of such queries themselves. We set Rookie to user state (Q=“Betrand Aristide”, F =“United States” and T =1987-2007) whichselects 830 documents—and we loaded IR with the query “BetrandAristide United States” which selects 841 documents. For the IRsystem, we disabled the search bu�on during the task—users werenot allowed to change the query, but could use datepickers to zoomin on certain dates. For Rookie, users could not change Q or F, butcould vary T. �us, this experiment measures well Rookie’s linkedtemporal browsing and sentence-sum help users learn the answerto a question—it does not measure other aspects of the full RookieUI.

Users were instructed to research until they were reasonablycon�dent in their answer, then submit a response. �ey were alsorequired to copy and paste two sentences from sentence-sum tosupport their multiple choice selection. By requiring evidence, weavoided junk responses and signaled to participants that answerswill be scrutinized—following best practices [26] for user interfacestudies conducted via MTurk. In the analysis below, we analyzetime to completion in cases where workers answered the questioncorrectly, in order to ensure we are measuring “good faith” [26]a�empts to complete the task.

5.3 Results and analysis

Limiting our results to the 26 workers who found the correct answerwith the IR system and 27 workers who found the correct resultwith the Rookie system, we �nd Rookie users complete the taskfaster; in seconds:

Mean Std. Dev.Rookie 285.1 (169.8)IR 451.0 (217.5)

0369

0369

rookieir

0 500 1000seconds

coun

t

While there is considerable variation within each group, Rookieusers, on average, completed the task 166 seconds faster (using37% less time); the di�erence is statistically signi�cant (p = 0.003,t-test or p = 0.001, non-parametric Mann-Whitney test). �e fastestIR user completed the task in 210 seconds, but 12 Rookie users�nished faster than that. Interestingly, the choice of system did nota�ect accuracy of the results—roughly half of both groups got thequestion right, and among users who submi�ed incorrect answers,completion times were similar (232 (149) vs. 460 (277)).

Examining system logs forRookie and IR, we �nd that 25 success-ful IR users opened individual news stories for inspection (viewing6.4 stories on average) while only 7 successful Rookie users openedindividual stories for inspection (viewing 2.0 stories on average).(By successful, we mean answered the question correctly). �issuggests that IR users solved the task by reading documents, butRookie users solved the task by reading summaries. Interestingly,the most frequently requested document by Rookie users, which de-scribes how Aristide �ed Haiti in 2004 ahead of U.S. troops, was notrequested by a single IR user. �e headline and Whoosh snippet forthat document only describe the United States—not its relationshipto Aristide. In contrast, for that document, Rookie’s sentence-sumshows a sentence that describes the US and Aristide.

Page 7: Rookie: A unique approach for exploring news archives

Rookie: A unique approach for exploring news archives DS+J’17, August 2017, Halifax, Nova Scotia, Canada

6 REAL-WORLD JOURNALISM AND NLP

Natural language processing researchers have developed manytechniques for extracting entities, relations, events, topics [2] orsummaries from news archives (see Grishman [19] and Das [8] forsurveys). Such work, in the words of Jonathan Stray [42], sometimes“discusses journalism as a potential application area without everconsulting or testing with journalists”.

Rookie is one of a handful of projects, including Vox Civitas [10]and Overview [3] which seek apply work from the NLP researchcommunity using feedback and input from actual readers, writersand editors.

During development, we consulted with three reporters, twonews editors, a journalism professor and a new media applicationsdeveloper. We spent nearly 18 months testing features and modify-ing the design before we began formal user testing. Several crucialthemes emerged from this process. We strongly suspect that theselessons would apply to others seeking to join journalism and NLP.

6.1 Practical systems should handle NLP

failures with grace

Early versions of Rookie a�empted to produce authoritative sum-maries of queried documents. One early version of sentence-suma�empted to combine multiple phrases and sentences from acrossdocuments without line breaks (similar to Zagat12 reviews). An-other early version showed only the top N topics in subjects-sum,or the top N sentences in sentence-sum, without pagination. �esedesigns were well-intentioned: we hoped to cut through “informa-tion overload” [39] and present users with only the most importantdata.

However, users reported confusion and frustration with our �rsta�empts. �ey did not understand Rookie’s long and sometimesincoherent summaries—and they were annoyed when Rookie onlyshowed the top 5 most important sentences or phrases for display.In the �rst case, we had trouble accounting for discourse e�ectsin summaries, so sentences strung together into a long summarydid not necessarily make sense as a whole. In the later case, wea�empted to create an authoritative, �xed-width summary (eitherwith a list of 5 terms or a list of 5 sentences)—without allowingusers to expand the summary as needed using pagination, as in thecurrent design.

Because state of the art NLP systems are not able to produce per-fectly grammatical extractive or abstractive summaries (e.g. [36])it is thus important to design summarization interfaces which arerobust to such errors. In Rookie, we did this by (1) spli�ing eachextracted sentence into a standalone snippet (protecting againstungrammatical or semantically nonsensical multi-sentence sum-maries) and (2) allowing for pagination (protecting against poorcomputational judgements about importance). Informal feedbackimproved.

�is insight about summarization generalizes to other sorts ofso�ware that uses NLP judgements for computational journalism,such as newsroom so�ware which uses NLP to �nd entities, extractevents or resolve coreference. Designers and developers must buildsystems which can handle inevitable failures [32].

12e.g. h�p://www.zagat.com/r/franklin-barbecue-austin

6.2 Text visualization should support drill

down to actual words

Early versions of Rookie’s time series graph simply showed thefrequencies of stories through time, without the rich interactionsshown in �g. 2. However, in testing Rookie, we found that usersassumed that they could manipulate the time series graph to drilldown for more detail—and were confused when they could notdo so. One editor explained: “It is useful to see how many storiesappear in a given month. But that is not clickable. How are youhelping the user by providing information that they can’t act on”?

We thus modi�ed the time series graph to allow users to movesmoothly from visualization to underlying text. Again, informalfeedback improved. We think that this insight might also be appliedto other text visualizations like metro maps [38], entity–relationgraphs [18] or t-SNE plots of word distances [28]. In particular,popular time series frequency visualizations such as the GoogleN-Grams Viewer13 or New York Times Chronicle14, which show thefrequency of a word or phrase through time, could be improvedwith some form of textual drilldown like a KWIC view or list ofunderlying documents. As Gorg et al.[18] explain following yearsof development of one text analytics system: “interactive visualiza-tion of connections between entities and documents alone cannotreplace the reading of reports”.

6.3 NPs, not entities (or topics)

Many text previous systems have sought to help users exploreand make sense of documents [10, 17, 25, 31], including so�warespeci�cally designed for news archives [11, 47], so�ware speci�callydesigned for reporters [3], and so�ware focused on evolving topicsthough time [7, 12, 13, 44].

All such systems extract some interesting ”aspects” of text, andpresent them to users for visualization and navigation. Some �ndand display entities and relationships.15 Others �nd and displaylearned word clusters or “topics” [7, 12, 13, 44], sometimes arrangedin a hierarchy. A third approach relies on manually-created tags[11, 47].

Each of these established method has limitations. State of the artNER systems [14, 16] incorrectly tag or fail to recognize entities.Learned topics can miss categories de�ned by domain experts, orgenerate topics that do not make sense [5]. Human annotation isexpensive and o�en infeasible.

Rookie thus takes a very di�erent approach: �nd noun phrases(NPs) and let the user quickly browse them, drawing a�entionto co-occurrence relationships and phrases in context. �is rapidbrowsing replaces topical term clustering or relation identi�cationin other systems for exploring news text. NPs have many advan-tages over entities and topics.

Unlike topics, NPs can be expressed concisely and understoodquickly, without reading and interpreting lists of (possibly non-sensical) words from a topic model. Moreover, where inferencefor a topic model incurs latency (a major disadvantage in a user-facing system), simple lists of important NPs can be generated very

13h�ps://books.google.com/ngrams/graph?content=mobile14h�p://chronicle.nytlabs.com/?keyword=mobile15e.g. h�ps://www.media.mit.edu/projects/news-graph/overview/ or h�ps://neo4j.com/blog/analyzing-panama-papers-neo4j/

Page 8: Rookie: A unique approach for exploring news archives

DS+J’17, August 2017, Halifax, Nova Scotia, Canada Abram Handler and Brendan O’Connor

quickly in response to user queries. �is is discussed further in§6.4.

Similarly, unlike NER and relations, NPs can be extracted withvery high accuracy, which is vital to user-facing systems wherenonsensical output from NER systems may confuse users unfamiliarwith NLP. Additionally, where NER systems require a prede�nedontology, NPs work ‘o� the shelf’ on many corpora [20], o�er-ing the �ne-grained speci�city of entity–relation systems withoutspecialized annotations or a prede�ned knowledge base.

Note that unlike the NER systems that are usually more popularin computational journalism [42, p. 4], NP extraction is less tied toannotation decisions in labeled data and imposes fewer assumptionsabout the semantic types needed for an application. In Rookie,NPs included valuable concepts like “eye doctor” or “Assad family”,which are important to understand queries like Q=“Bashar al-Assad”,but which do not refer to the sort of concrete entities which typicallyserve as the basis for conventional NER systems. Other work [15]shows the e�cacy of Rookie’s NP extraction at scale.

�e particular justi�cation and theory for Rookie’s subjects-sum extraction method is discussed in Handler et al. [20], followingan active area of NLP research in automatically identifying “im-portant” phrases in corpora, sometimes called keyphrases [6], mul-tiword expressions, or facets [41]. We consider subjects-sum anapplication of faceted search. See Hearst [22] for more discussion.

6.4 Speed, correctness and interpretability are

not optional

In designing Rookie, we required that each UI component could begenerated quickly, interpreted easily by ordinary users and wouldnever make a mistake in presenting some semantic representationof the underlying text. �ese requirements proved useful.

Speed. Others [23] have pointed out that “To be most e�ective,visual analytics tools must support the �uent and �exible use ofvisualizations at rates resonant with the pace of human thought.”We followed this advice in building Rookie. In particular, NLPhas developed many techniques for summarization which requireseveral seconds of compute time [30], which is much too slow foruse in a UI. During the design process, we implemented one suchmethod [9] using a multithreaded implementation in C which em-ployed CVBO [1], a variational method for rapid inference for topicmodels. Our implementation still proved too slow for interactiveuse. �e trouble is that if summarization code runs on the server,then each time a user adjusts Q, F or T, Rookie must (a) makea call across a network to fetch a new summary (b) wait for theserver to generate the summary and (c) wait for the reply. Suchlatency costs are unacceptable in user-facing applications. Fast,approximate summarization techniques [30] which run client-sidein the browser are an exciting possibility for future research.

Correctness and interpretability. Rookie’s time series is consid-erably simpler than other text visualizations proposed for newsarchives, many of which show evolving themes across time [7, 12,13, 21, 44]. �is was a deliberate design choice. Rookie’s line chartsshowing a single lexical item certainly cannot represent clusters ofrelated vocabulary or “topics”, nor can they show the relationshipsbetween such topics. However, accurately summarizing topicalrelationships and their evolution is an AI-hard research challenge.

Because Rookie was designed for real world use, we chose a vi-sualization technique that could not confuse or mislead users byextracting and displaying nonsense clusters or missing importanttopics in the text. We show that Rookie’s simple line charts improveuser understanding, and we welcome such demonstrations for othermore complex approaches.

7 CONCLUSION AND FUTUREWORK

Rookie began as an e�ort to develop a useful tool for news re-porters. Because of this, Rookie’s design is dramatically di�erentfrom earlier systems designed to help navigate archived news. Ourapproach o�ers lessons for others seeking to use techniques fromNLP in the service of journalism.

ACKNOWLEDGMENTS

�anks to Steve Myers, Gabe Stein, Sanjay Kairam, Xiaolan Wang,Lane Harrison, John Foley, Rodrigo Zamith, Su Lin Blodge� andKatie Keith. �is work was partly supported by a Knight Prototypegrant to �e Lens in New Orleans.16

REFERENCES

[1] Arthur Asuncion, Max Welling, Padhraic Smyth, and Yee Whye Teh. 2009. Onsmoothing and inference for topic models. In Uncertainty in Arti�cial Intelligence,Vol. 100.

[2] David M Blei, Andrew Y Ng, and Michael I Jordan. 2003. Latent dirichlet alloca-tion. Journal of machine Learning research 3, Jan (2003), 993–1022.

[3] Ma�hew Brehmer, Stephen Ingram, Jonathan Stray, and Tamara Munzner. 2014.Overview: �e Design, Adoption, and Analysis of a Visual Document MiningTool for Investigative Journalists. IEEE Trans. Vis. Comput. Graph. 20 (2014),2271–2280.

[4] Andreas Buja, John Alan McDonald, J. Michalak, and Werner Stuetzle. 1991.Interactive Data Visualization Using Focusing and Linking. In IEEE Visualization.

[5] Jason Chuang, Sonal Gupta, Christopher D. Manning, and Je�rey Heer. 2013.Topic Model Diagnostics: Assessing Domain Relevance via Topical Alignment.In ICML.

[6] Jason Chuang, Christopher D. Manning, and Je�rey Heer. 2012. “Without theClu�er of Unimportant Words”’: Descriptive Keyphrases for Text Visualization.ACM Trans. on Computer-Human Interaction 19 (2012), 1–29. Issue 3. h�p://vis.stanford.edu/papers/keyphrases

[7] Weiwei Cui, Shixia Liu, Li Tan, Conglei Shi, Yangqiu Song, Zekai Gao, Huamin�, and Xin Tong. 2011. TextFlow: Towards Be�er Understanding of EvolvingTopics in Text. IEEE Trans. Vis. Comput. Graph. 17 (2011), 2412–2421.

[8] Dipanjan Das and Andre FT Martins. 2007. A survey on automatic text summa-rization. (2007).

[9] Hal Daume III and Daniel Marcu. 2006. Bayesian query-focused summarization.In Proceedings of the 21st International Conference on Computational Linguisticsand the 44th annual meeting of the Association for Computational Linguistics.Association for Computational Linguistics, 305–312.

[10] Nicholas Diakopoulos, Mor Naaman, and Funda Kivran-Swaine. 2010. Diamondsin the rough: Social media visual analytics for journalistic inquiry. In VisualAnalytics Science and Technology (VAST), 2010 IEEE Symposium on. IEEE, 115–122.

[11] Marian Dork, Sheelagh Carpendale, Christopher Collins, and Carey Williamson.2008. Visgets: Coordinated visualizations for web-based information explorationand discovery. IEEE Transactions on Visualization and Computer Graphics 14, 6(2008), 1205–1212.

[12] Wenwen Dou, Xiaoyu Wang, Remco Chang, and William Ribarsky. 2011. Paral-lelTopics: A Probabilistic Approach to Exploring Document Collections. In IEEEVAST. 231–240.

[13] Wenwen Dou, Li Yu, Xiaoyu Wang, Zhiqiang Ma, and William Ribarsky. 2013.HierarchicalTopics: Visually Exploring Large Text Collections Using Topic Hier-archies. IEEE Trans. Vis. Comput. Graph. 19 (2013), 2002–2011.

[14] Greg Durre� and Dan Klein. 2014. A Joint Model for Entity Analysis: Coreference,Typing, and Linking. TACL 2 (2014), 477–490.

[15] John Foley, Brendan O’Connor, and James Allan. 2016. Improving Entity Rankingfor Keyword �eries. In Proceedings of CIKM.

[16] Ma�hew Francis-Landau, Greg Durre�, and Dan Klein. 2016. Capturing SemanticSimilarity for Entity Linking with Convolutional Neural Networks. In HLT-NAACL.

16h�p://www.knightfoundation.org/grants/201550791/

Page 9: Rookie: A unique approach for exploring news archives

Rookie: A unique approach for exploring news archives DS+J’17, August 2017, Halifax, Nova Scotia, Canada

[17] Carsten Gorg, Youn-ah Kang, Zhicheng Liu, and John Stasko. 2013. Visualanalytics support for intelligence analysis. (2013).

[18] Carsten Gorg, Zhicheng Liu, and John Stasko. 2013. Re�ections on the evolutionof the Jigsaw visual analytics system. Information Visualization (2013).

[19] Ralph Grishman. 2012. Information Extraction: Capabilities and Challenges.(2012).

[20] Abram Handler, Ma� Denny, Hanna Wallach, and Brendan O’Connor. 2016. Bagof what? Simple noun phrase extraction for corpus analysis. NLP+CSS workshopat EMNLP (2016).

[21] Susan L. Havre, Elizabeth G. Hetzler, Paul Whitney, and Lucy T. Nowell. 2002.�emeRiver: Visualizing �ematic Changes in Large Document Collections. IEEETrans. Vis. Comput. Graph. 8 (2002), 9–20.

[22] Marti Hearst. 2009. Search user interfaces. Cambridge University Press.[23] Je�rey Heer and Ben Shneiderman. 2012. Interactive dynamics for visual analysis.

�eue 10, 2 (2012), 30.[24] Harry Hochheiser and Ben Shneiderman. 2004. Dynamic query tools for time

series data sets: Timebox widgets for interactive exploration. Information Visu-alization 3 (2004), 1–18. Issue 1.

[25] Ellen Isaacs, Kelly Damico, Shane Ahern, Evgeniy Bart, and Manav Singhal.2014. Footprints: A Visual Search Tool that Supports Discovery and CoverageTracking. Visualization and Computer Graphics, IEEE Transactions on 20, 12(2014), 1793–1802.

[26] Aniket Ki�ur, Ed H. Chi, and Bongwon Suh. 2008. Crowdsourcing User Studieswith Mechanical Turk. In Proceedings of the SIGCHI Conference on Human Factorsin Computing Systems (CHI ’08). ACM, New York, NY, USA, 453–456. h�ps://doi.org/10.1145/1357054.1357127

[27] Zhicheng Liu and Je�rey Heer. 2014. �e E�ects of Interactive Latency onExploratory Visual Analysis. IEEE Trans. Visualization & Comp. Graphics (Proc.InfoVis) (2014). h�p://idl.cs.washington.edu/papers/latency

[28] Laurens van der Maaten and Geo�rey Hinton. 2008. Visualizing data using t-SNE.Journal of Machine Learning Research 9, Nov (2008), 2579–2605.

[29] Gary Marchionini. 2006. Exploratory Search: From Finding to Understanding.Commun. ACM 49, 4 (April 2006), 41–46. h�ps://doi.org/10.1145/1121949.1121979

[30] Ryan McDonald. 2007. A study of global inference algorithms in multi-documentsummarization. In European Conference on Information Retrieval. Springer, 557–564.

[31] Aditi Muralidharan and Marti Hearst. 2011. WordSeer: Exploring LanguageUse in Literary Text. In Fi�h Workshop on Human-Computer Interaction andInformation Retrieval.

[32] Khanh Nguyen and Brendan O’Connor. 2015. Posterior calibration and ex-ploratory analysis for natural language processing models. In Proceedings ofthe 2015 Conference on Empirical Methods in Natural Language Processing. As-sociation for Computational Linguistics, Lisbon, Portugal, 1587–1598. h�p://aclweb.org/anthology/D15-1182

[33] Jakob Nielsen. 1993. Usability Engineering. Morgan Kaufmann Publishers Inc.,San Francisco, CA, USA.

[34] Brendan O’Connor. 2014. MiTextExplorer: Linked brushing and mutual informa-tion for exploratory text data analysis. In Proceedings of the ACL Workshop onInteractive Language Learning, Visualization, and Interfaces.

[35] Peter Pirolli, Patricia Schank, Marti Hearst, and Christine Diehl. 1996. Scat-ter/Gather Browsing Communicates the Topic Structure of a Very Large TextCollection. In CHI. ACM, 213–220.

[36] Alexander M Rush, Sumit Chopra, and Jason Weston. 2015. A neural a�entionmodel for abstractive sentence summarization. arXiv preprint arXiv:1509.00685(2015).

[37] Evan Sandhaus. 2008. �e New York Times Annotated Corpus. Linguistic DataConsortium LDC2008T19 (2008).

[38] Dafna Shahaf, Carlos Guestrin, and Eric Horvitz. 2012. Trains of thought: Gen-erating information maps. In Proceedings of the 21st international conference onWorld Wide Web. ACM, 899–908.

[39] Dafna Shahaf, Jaewon Yang, Caroline Suen, Je� Jacobs, Heidi Wang, and JureLeskovec. 2013. Information cartography: creating zoomable, large-scale mapsof information. In Proceedings of the 19th ACM SIGKDD international conferenceon Knowledge discovery and data mining. ACM, 1097–1105.

[40] Ben Shneiderman. 1996. �e eyes have it: A task by data type taxonomy forinformation visualizations. In Proceedings of IEEE Symposium on Visual Languages.IEEE, 336–343.

[41] Emilia Stoica, Marti A Hearst, and Megan Richardson. 2007. Automating Creationof Hierarchical Faceted Metadata Structures.

[42] Jonathan Stray. 2016. What do Journalists do with Documents?. h�p://jonathanstray.com/what-do-journalists-do-with-documents. In Computa-tion+Journalism Symposium. Retrieved January 10, 2016.

[43] Stef van den Elzen and Jarke J van Wijk. 2013. Small multiples, large singles: Anew approach for visual data exploration. In Computer Graphics Forum, Vol. 32.Wiley Online Library, 191–200.

[44] Furu Wei, Shixia Liu, Yangqiu Song, Shimei Pan, Michelle X. Zhou, WeihongQian, Lei Shi, Li Tan, and Qiang Zhang. 2010. TIARA: A Visual Exploratory TextAnalytic System. In KDD. 153–162.

[45] Ryen W. White, Gary Marchionini, and Gheorghe Muresan. 2008. EvaluatingExploratory Search Systems: Introduction to Special Topic Issue of InformationProcessing and Management. Information Processing & Management 44, 2 (2008),433–436.

[46] Ryen W. White and Resa A. Roth. 2009. Exploratory Search: Beyond the �ery-Response Paradigm. Morgan and Claypool Publishers.

[47] Jing Yang, Dongning Luo, and Yujie Liu. 2010. Newdle: Interactive visual explo-ration of large online news collections. IEEE computer graphics and applications30, 5 (2010), 32–41.