=Paper= {{Paper |id=None |storemode=property |title=Exploiting Inference to Improve Temporal RDF Annotations and Queries for Machine Reading |pdfUrl=https://ceur-ws.org/Vol-966/STIDS2012_T13_Schrag_InferenceInTemporalRDF.pdf |volume=Vol-966 |dblpUrl=https://dblp.org/rec/conf/stids/Schrag12a }} ==Exploiting Inference to Improve Temporal RDF Annotations and Queries for Machine Reading== https://ceur-ws.org/Vol-966/STIDS2012_T13_Schrag_InferenceInTemporalRDF.pdf
         Exploiting inference to improve temporal RDF
          annotations and queries for machine reading

                                                         Robert C. Schrag
                                                        Digital Sandbox, Inc.
                                                          McLean, VA USA
                                                         bschrag@dsbox.com


  Abstract—We describe existing and anticipated future benefits      inferable bounds between any two points and will detect
of an end-to-end methodology for annotating formal RDF               contradictory time point relation sets.
statements representing temporal knowledge to be extracted               A fluent is an object-level, domain statement (e.g., FluentA:
from text, as well as for authoring and validating test and/or       attendsSchool(Jansa LubljanaUniversity)) whose truth value is
application queries to exercise that knowledge. Extraction is        a function of time. It is taken to be true at time points where it
driven by a target ontology of temporal and domain concepts
                                                                     holds and not to be true at time points where it does not hold.
supporting an intelligence analyst’s timeline tool. Both the tool
                                                                     We reify a fluent in an observation—a meta-level statement
and the methodology are supported at several points by an
implemented temporal reasoning engine, in a way that we argue        whose object is a fluent, whose subject is a time interval, and
ultimately advances machine reading technology by increasing         whose      predicate      is    a      holds    property     (e.g.,
both sophistication and quality expectations about temporal          holdsThroughout(FluentA Interval1), when FluentA is observed
annotations and extraction.                                          over Interval1, corresponding to, say, September, 1980).
                                                                         The events of interest to us, which we call transition events,
    Index Terms—temporal knowledge representation and                occur at individual time points and may cause one or more
reasoning, extracting formal knowledge from text, machine            fluents to change truth value. We represent events (like the
reading, annotation interfaces and validation                        birth of Jansa) as objects with attribute properties like agent,
                                                                     patient, and location, and we relate events to time intervals with
                        I. INTRODUCTION                              an occurs property (e.g., occursAt(BirthOfJansa Point2), where
    Machine reading—that is, automatic extraction of formal          Point2 is associated with an interval corresponding to the date
knowledge from natural language text—has been a                      September 17, 1958). As usual with the event calculus, such
longstanding goal of artificial intelligence. Effective extraction   events can initiate fluents (e.g., occursAt(BirthOfJansa Point2)
into RDF has the potential to make targeted knowledge                initiates FluentB: alive(Jansa Interval3), where Interval3 is
accessible in the semantic web. We recently supported a large-       begun by Point2) or terminate them (e.g., DeathOfJansa… ).
scale evaluation of temporal knowledge extraction from text by       The temporal reasoning engine implements appropriate axioms
providing RDF/OWL ontology for target statements and a               to perform fluent initiation and termination.
corresponding reasoning engine for query answering. Along                Note that an observer may report information about the
the way, we discovered…                                              temporal extent of a fluent without communicating anything
    • How inference could improve annotation—the manual              about initiation or termination. E.g., if text says Abdul and
        extraction of formal temporal statements—and                 Hasan lived next door to each other in Beirut in 1999, we don’t
        question authoring for evaluation or for applications.       know when Abdul or Hasan may have moved to or from
    • How, coupled with annotation and question authoring            Beirut. When text says Abdul moved to Beirut in 1995 and
        processes, inference could ultimately drive more             emigrated in 2007, we use the properties clippedBackward and
        sophisticated machine reading capabilities.                  clippedForward regarding the fluent residesInGPE-spec(Abdul
                                                                     BeirutLebanon) to indicate initiation and termination by
       II. TEMPORAL KNOWLEDGE REPRESENTATION AND                     anonymous (unrepresented) transition events, so that we can
           REASONING FOR TIMELINE DEVELOPMENT                        also initiate or terminate temporally under-constrained like-
    Our temporal logic is based loosely on the event calculus        fluent observations (e.g. Abdul lived in Beirut during the
[10], as follows.                                                    1990s).
    A time interval is a convex collection of time points—               The     reasoning      engine’s      implementation,     using
intuitively, an unbroken segment of a time line. Time intervals      AllegroGraph, Allegro Prolog, and Allegro Common Lisp from
begin and end with time points, which may be constrained             Franz, Inc., can answer any conjunctive query. While not yet
relative to each other or relative to a calendar. The ontology       heavily optimized, it is at least fast enough to support machine
includes a rich set of relational properties over time points and    reading system evaluation over newspaper articles where cross-
intervals, and the reasoning engine will calculate tightest          document entity co-reference is not required.
    The combined extraction and reasoning capability was                 IV. LESSONS LEARNED WITH IMPLEMENTATION PROPOSED
conceived to support an intelligence analyst’s timeline tool in           Here, we propose some further approach elements that we
which a GUI would be populated with statements about entities         expect to lead to high-quality temporal annotations,
(e.g., persons) of interest extracted from text. Our evaluation       including…
of machine reading capabilities was based on queries similar to            A. Interfaces and workflows deliberately designed to
those we would have expected from such a tool’s API. It also                   support capture of all statements specified as
supposed the analysts could formulate their own, arbitrary                     extraction targets (see section A)
questions, such as Query 1: Find all persons who were born in
                                                                           B. Graphical time map display including fluents and
Ljubljana in the 1950s and attended Ljubljana University in the
                                                                               events (see section B)
1980s, the titles that they held, the organizations in which they
held these titles, and the maximal known time periods over                       • On-line inference to elucidate inter-
which they attended and held these titles.                                            relationships and potential contradictions
                                                                                 • Visual feedback to let users help assure quality
  III. LESSONS LEARNED AND REALIZED IN IMPLEMENTATION                                 themselves
    This indirect, query answering style of machine reading                      • Time map-based widgets supporting user
evaluation makes it especially important that we perform                              knowledge entry
effective quality control of formal queries in the context of the          C. Technology adaptable to test or application question
formal statements we expect to be extracted from answer-                       authoring (see section C)
bearing documents. We thus developed the test query                        D. Quantitative temporal relation annotation evaluation
validation approach illustrated in Figure 1. Considering Query                 (see section V.A).
1’s formalization (see Figure 10 in section IV.B), it’s worth         A. Annotation workflows
noting that we used the methodology illustrated here to debug a
                                                                           Fluents are simple statements that we can readily represent
number of subtle errors occurring in our earlier (manual)
                                                                      in RDF. The example in Figure 2 focuses on the fluent about
formulations. When each such formulation did not result in the
                                                                      one Janez Jansa attending Ljubljana University—only on the
answers expected, we traced inference to identify a point of
failure, corrected this, and then iterated until correct.             fluent, not the full observation including temporal information
                                                                      (i.e., only that Jansa attends the school, not when). The
    Our machine reading technologists told us early on that
                                                                      technology needed to annotate such information is well
they preferred macro-level relational interfaces that would
                                                                      understood and (excepting perhaps the last bullet about
streamline away micro-level details of time points and
                                                                      modality) has been well enough exercised that we may
intervals. We thus provide a language of flexible specification
                                                                      routinely expect good results. This includes multi-frame GUIs
strings (spec strings) that expand to create time points,
                                                                      where a user can produce stand-off annotations by highlighting
intervals, and relations inside our reasoning engine. We also
                                                                      text and by clicking in drop-down boxes select relations,
provide ontology to associate the temporal aspects Completed,
                                                                      classes, and instances. In part because these tools have
Ongoing, and Future with fluents (e.g., he used to live there vs.     preceded reading for formal knowledge extraction, they may
he is living there vs. he is going to live there) and with the        not use our intended representation internally—i.e., they may
reporting dates of given articles, to afford a relational interface   for historical reasons internally use a representation (e.g., XML
reasonably close in form to natural language sources. For the         that is not RDF) tailored to linguistic phenomena rather than
Completed or Future aspects, we also can capture quantitative         associated with any formal ontology.
lag or lead information (e.g., he lived there five years ago or he
will move in five days from now).

                                                              Diagnose KR&R issues.
                                                                                                                  Compare answers.
                  Formalize.




                               Given NL…               Document                   Query         Answer(s)
                                               Manually author selected          Formalize        Execute
                               Produce            statements to support             query.        query to
                               KR…                  expected inference.                         get results.

                                                       Apply temporal reasoning engine.
    Figure 1. We validate test queries by making sure that natural language (NL) and formal knowledge representation (KR)
                 versions of documents, queries, and answers agree, diagnosing and debugging as necessary.
                                                                     1.     Select relation.
                     …Jansa graduated from                           2.     Specify argument identifiers, respecting
                     Ljubljana University…                                  co-reference.
                                                   Source text       3.     Select / highlight / designate
                                                                            corresponding text.
                       Formalization                                 4.     Capture any counter-factual modality info.

                    attendsSchool(Janez_Jansa Ljubljana_University)
                                             Figure 2. The workflow to annotate a fluent

                                                                    1. Select one of time interval or point.
                                                   Reporting
                                                     date           2. Capture any beginning date and backward
                          Dec 28, 2007…                                clipping info.
                                                                    3. Capture any ending date and forward
                         …Jansa graduated from                         clipping info.
                         Ljubljana University in                    4. Capture any duration info.
                         1984…                                      5. If ending point is unconstrained w.r.t.
                                                                       reporting date:
                                                                           a. Capture reporting aspect.
                                                                           b. Capture any reporting lag info.
                                                                    6. Capture any other relative temporal info
                                                                       available.
                                                                                     Fluent clipped forward
                                                                                        at ending point
                          attendsSchool(Janez_Jansa Ljubljana_University)

                                                                          1984                   Entered info (user writes)
                    [,1984-12-31]                              [1984-01-01,1984-12-31]           Inferred info (user reads)
                            Figure 3. The workflow to annotate a holds statement (a fluent observation)
    Capturing the temporal information associated with the                       •   There is no duration information. (We don’t know
given observation of a fluent in a holds statement requires                          how long Jansa was at school.)
following a sequence of actions and decisions in a deliberately                • The ending point is well before the reporting date, so
designed workflow, as outlined in Figure 3. We have                                  we skip to the next step.
highlighted, by color- and typeface-coding, some temporal                      • There is no other relevant temporal information.
elements in the source text, along with corresponding steps in                 • To indicate clipping, the graphic fills the time point
the workflow and elements of the associated graphical                                symbol (making it solid).
representation.                                                                Our reasoning engine expands the entered coarse date 1984
    Addressing the workflow step by step, we see that:                     into earliest and latest possible calendar dates bounding the
    • There is no reason to believe Jansa attended school for              observation’s ending point. It also infers an upper bound on its
        only one day (the time unit associated with a time                 beginning time point.
        “point” in our machine reading evaluation), so we                      As illustrated in Figure 4, we invoke a similar workflow for
        choose a time interval (and the predicate                          event occurrence. Because our representation for events is
        holdsThroughout) rather than a time point (and                     simpler than that for observations, this workflow has fewer
        holdsAt). Schrag [8] argues that holdsAt almost never              steps. Our ontology treats birth as a fluent transition event—it
        is appropriate, and in future this step may be omitted.            occurs at a given time point, and it causes a transition of the
    • We find no beginning date information. (In the                       vital status of the person born (from FuturePerson to Alive).
        absence of such information, there is no benefit to                Our graphical representation here accordingly just depicts a
        asserting backward clipping.)                                      single time point (not an interval). We can use basically the
    • We find (and have highlighted) a coarse-grained                      same workflow to capture a non-transition event (e.g., a legal
        ending date (1984). We indicate that our fluent is                 trial) that occurs over more than one time point.
        clipped forward, assuming that Jansa no longer attends
        the school after graduation.
                           …Born on September 17,                         1. Select event type.
                           1958 in Ljubljana, Jansa…                      2. Specify argument identifiers,
                                                                             respecting co-reference.
                                                                          3. Select / highlight / designate
                                                                             corresponding text.
                                                                          4. Capture any hypothetical modality
                                                                             info.
                                                                          5. Capture any date info.
                                                                          6. If an event’s date is otherwise
                                                                             unconstrained w.r.t. reporting date:
                     BirthEvent(Janez_Jansa, Ljubljana)                         a. Capture reporting aspect.
                                                                                b. Capture any reporting lag info.
                                   1958-09-17                             7. Capture any other relative temporal
                                                                             info available.


                                           Figure 4. Workflow to annotate a transition event

                    BirthEvent(Janez_Jansa, Ljubljana)
                                                                                On demand:
                    1958-09-17                                                  • Trace back from bounds to user-
                          attendsSchool(Janez_Jansa Ljubljana_University)          entered information.
                                                         [0D,15Y3M12D]               o   Date of the birth event
                           [1958-09-18,1984-12-31] 1984
                                                                                •   Display / hide entered or inferred
                                                                                    bounds on…
                      Automatically:                                                 o   Beginning points, ending points
                      • Display in order any time points that are                    o   Durations
                         ordered unambiguously.                                 •   Focus on a particular time
                      • Display inferred bounds.                                    window, location, person, …
                            o   Rules: Can’t attend school before being         •   Highlight time points that are
                                alive; being born makes one alive.                  ordered / unordered w.r.t. to a
                      •    Highlight bounds contradictions.                         selected, reference time point.


                                    Figure 5. A time map with both a fluent and a transition event
                                                                            judgments about the information they enter. If any inferred
B. Displaying integrated time maps                                          bound seemed odd, a user could click on it to identify which of
    Figure 5 illustrates a time map including both the birth                his/her own entered information (then highlighted in the
event and the school attendance fluent from earlier figures. It             display) might be responsible. The time map display tool
also suggests functional requirements to be satisfied                       would automatically launch such an interaction when it
automatically/by default and upon user demand. Note that we                 detected a contradiction among inputs.
now have automatically displayed—from on-line temporal                          The time map displayed in Figure 6 includes all the
inference—a lower bound on the fluent observation’s                         information from the source text that is necessary to answer
beginning date: Jansa could not have attended school until after            Query1. The last fluent observation (at bottom right, where
he was born. (The “day” time point granularity used in our                  Jansa is prime minister) exercises workflow steps that earlier
machine reading evaluation leads to some non-intuitive effects,             time map elements don’t. We have no ending date for this
like not being alive until the day after one is born. We can                observation, but we do have present tense reference to Jansa as
easily correct this using an interval constraint propagation                the prime minister, so we appeal to the reporting aspect
arithmetic including infinitesimals [6][7][8].) We’ve also                  Ongoing. From the source text he was elected prime minister
indicated bounds on the fluent observation’s duration                       on November 9, 2004, we can bound the observation’s
(calculated as ending date bounds interval minus starting date              beginning point.
bounds interval). Propagating effects like this can maximize
visual feedback to users, expanding their basis for quality
                     BirthEvent(Janez_Jansa, Ljubljana)


                     1958-09-17
                          attendsSchool(Janez_Jansa Ljubljana_University)
                                                         [0D,9235D]
                           [1958-09-18,1984-12-31]  1984

                                                        personHasTitleInOrganization(Janez_Jansa Defence_Minister Slovenia)

                                                                   1990     1994

                    personHasTitleInOrganization(Janez_Jansa Defence_Minister Slovenia)                    ElectionEvent(Slovenia,
                                                                                                                         Prime_Minister,
                                                                                    2000      2000         2004-11-09 Janez_Jansa)


                                                         personHasTitleInOrganization(Janez_Jansa Prime_Minister Slovenia)

                                                                                                    [2004-11-09, 2007-12-28]   2007-12-28
                        Slovenia national election day 2004,
                        per user-established relative temporal
                                                                                            Reporting date, via reporting
                                      reference
                                                                                                  aspect Ongoing

                             Figure 6. A time map with more statements extracted from the same article



                                                                                                         ElectionEvent(Slovenia,
                                                                 Widget: User selects:                                 Prime_Minister,
                                                                   • Relation (from menu)
                                                ,                                                                      Janez_Jansa)
                                                                   • Subject , object (via mouse)        2004-11-09
                                                ‘
                                                    ‘
                                            ‘
                                           ‘
                                                    ‘
                                                        personHasTitleInOrganization(Janez_Jansa Prime_Minister Slovenia)

                                    ‘
                                ‘



                                        Figure 7. Using the GUI to establish relative temporal reference
    Our user also has entered the election event. An election is                      access to these effectively, so that our user is empowered
not necessarily a fluent transition event, at least in that an                        without being overwhelmed.
elected candidate does not always take office immediately. So,                            Figure 8 shows formal statements that would be created
we rely on the user to establish relative temporal reference                          directly by the user’s actions (i.e., not also including those
between the election event and the fluent observation’s                               created indirectly by inference) in entering the information
beginning. See the depicted constraint, whose entry is                                reflected in our finished time map. We have highlighted
illustrated in Figure 7. Establishing relative temporal reference                     fluents and some other key statements, each of which appears
requires the selection of a pair of time points and/or intervals to                   near several related statements. Our time map represents
be related and of an appropriate temporal relation between                            Jansa’s birth event in a non-standard way, repeated here in
them. Here, we just need the time point at which the election                         different color type, beside the italicized, standard statements.
occurs to be less than or equal to the time point at which Jansa                      We have not similarly formalized the event of Jansa’s election
takes office.                                                                         as PM, and Figure 8 includes just statements about that event’s
    While a few common relations may be all that most users                           point of occurrence.
will ever need, we do have a lot of relations [8] that a user                             Clearly, we can do a lot of formal work for the user behind
could in principle choose from. We should be able to provide                          the scenes.
                     F_school: attendsSchool (Janez_Jansa Ljubljana_University)
                            holdsThroughout(F_school I_school)
                            clippedForward(F_school I_school)
                            hasTimeIntervalSpecString(I_school [,1984])
                            hasPersonBorn(birth Janez_Jansa)
                            occursAt(birth P_birth)
                            hasTimePointSpecString(P_birth 1958-09-17)          BirthEvent(Janez_Jansa, Ljubljana)
                            hasPersonBorn(birth Janez_Jansa)
                            hasBirthEventGPE-spec(birth GPEspec)
                            hasCityTownOrVillage(GPEspec ljubljana_Ljubljana_Slovenia)
                            hasNationState(GPEspec Slovenia)
                            type(Defence_Minister MinisterTitle)
                 F_PTIO_DM_1: personHasTitleInOrganization(Janez_Jansa Defence_Minister Slovenia)
                            holdsThroughout(F_PTIO_DM_1 I_PTIO_DM_1)
                            clippedBackward(F_PTIO_DM_1 I_PTIO_DM_1)
                            clippedForward(F_PTIO_DM_1 I_PTIO_DM_1)
                            hasTimeIntervalSpecString(I_PTIO_DM_1 [1990,1994])
                 F_PTIO_DM_2: personHasTitleInOrganization(Janez_Jansa Defence_Minister Slovenia)
                            holdsThroughout(F_PTIO_DM_2 I_PTIO_DM_2)
                            clippedBackward(F_PTIO_DM_2 I_PTIO_DM_2)
                            clippedforward(F_PTIO_DM_2 I_PTIO_DM_2)
                            hasTimeIntervalSpecString(I_PTIO_DM_2 [2000,2000])
                   F_PTIO_PM: personHasTitleInOrganization(Janez_Jansa Prime_Minister Slovenia)
                            holdsThroughout(F_PTIO_PM I_PTIO_PM)
                            clippedBackward(F_PTIO_PM I_PTIO_PM)
                            hasBeginningTimePoint(I_PTIO_PM I_PTIO_PM_beginning)
                            hasTimePointSpecString(Slovenia_2004_Election_Day 2004-11-09)
                            timePointGreaterThanOrEqualTo(I_PTIO_PM_beginning Slovenia_2004_Election_Day)
                            hasReportingAspect(I_PTIO_PM Ongoing)
                            ref(annotation I_PTIO_PM)
                            annotation(document annotation)
                            hasReportingChronusSpecString(document 2007-12-28)

                             Figure 8. Formal statements associated with the time map in Figure 6

                                                                         Query 1: Find all persons who were born in
                                 BirthEvent(?person, Ljubljana)
                                                                         Ljubljana in the 1950s and attended Ljubljana
                                                                         University in the 1980s, the titles that they held,
                                                                         the organizations in which they held these titles,
                                                                         and the maximal known time periods over which
                                                                         they attended and held these titles.
                    1950-01-01         1959-12-31


                                                attendsSchool(?person Ljubljana_University)
                                                                                                ?attendanceIntervalSpec




                                                       1980-01-01        1989-12-31

                                         personHasTitleInOrganization(?person ?title ?org)
                                                                                             ?titleIntervalSpec

                                              Figure 9. The time map covering our Query1
                                                                               •   We are asking about only one answer (set of variable
C. Adaptation to test or application question authoring
                                                                                   values satisfying the query) at a time. The supporting
    We might reuse much of the same machinery in a question                        statements in our earlier time map include three
authoring interface, in which a user can formalize a query, as                     separate sets of bindings for the variables ?title and
illustrated for Query1 in Figure 9. This time map display is                       ?org.
even less cluttered than the one for this query’s supporting                  We have introduced intervals to represent the 1950s and the
statements, for a couple of reasons.                                       1980s, and we have selected time point/interval relationships
    • We are making general statements, rather than specific               appropriate to the query’s conditions. These relationships are
          ones, so don’t use as many dates or long identifiers.            associated with particular idioms used in our formalization in
          Rather, we use variables (here beginning with ?).                Figure 10.
                                         hasPersonBorn(?birth ?person)
                                         hasBirthEventGPE-spec(?birth ?GPEspec)
                                         hasCityTownOrVillage(?GPEspec ljubljana_Ljubljana_Slovenia)
                                         hasTimeIntervalSpecString(?I_range_birth [1950-01-01,1959-12-31])
                                         occursWithin(?birth ?I_range_birth)
                                         hasTimeIntervalSpecString(?I_range_school [1980-01-01,1989-12-31])
                                         holdsWithin(?F_school ?I_range_school)
                                         maximallyHoldsThroughout(?F_school ?I_school)
                                         hasTimeIntervalSpecString(?I_school ?attendanceIntervalSpec)
                               ?F_title: personHasTitleInOrganization(?person ?title ?org)
                                         maximallyHoldsThroughout(?F_title ?I_title)
                                         hasTimeIntervalSpecString(?I_title ?titleIntervalSpec)

                         Figure 10. Formalization of the query in Figure 9’s time map, covering Query 1
    Our query asks about the “maximal known time periods”                 Others have applied limited temporal reasoning in post-
over which the fluents hold, and we associate (via a query             processing of temporal annotations, to…
authoring workflow step) an “interval spec” variable with each             A. Compute the closure of qualitative pairwise time
fluent’s observation interval. Per our formalization, this will be              interval relations, as one step in assessing a machine
bound, on successful query execution, to a string that describes                reader’s precision and recall performance (see section
lower and upper bounds on the observation interval’s                            A)
beginning point, ending point, and duration. The formalization             B. Ascertain the global coherence of captured qualitative
uses the properties occursWithin (for born in the 1950s) and                    relations (see section B).
holdsWithin (for attended school in the 1980s) to accommodate             Our implementation can go further, as described below.
the temporal relations selected for the query authoring time
                                                                       A. Quantitative temporal relation annotation evaluation
map. We know to use maximallyHoldsThroughout (vice the
less restrictive holdsThroughout) for the fluents’ observation             Evaluating temporal annotations typically has been limited
intervals because the query’s author has included (via the             to (Allen’s [1]) qualitative relations (e.g., before, overlaps,
invoked widget) associated spec string variables.                      contains), and quantitative information about dates and
    Thus, it appears that we might enable non-specialists to           durations typically has been evaluated only locally—at the
author effective test queries (or, in a transition/application         level of temporal expressions (AKA “TIMEXs” [3]). The
setting, domain queries), without requiring the intervention of a      reasoning applied has been strictly interval-based, neglecting
KR specialist. One angle on this proposed work might be to             important quantitative information about dates and durations
determine the extent to which readers who are not (temporal)           widely available in text. This approach is taken by Setzer et al.
knowledge representation specialists can perform such tasks            [9], e.g.
consistently—alternatively, to determine the amount of training            Our temporal reasoning engine, which is point-based,
(e.g., pages of documentation, number of successfully                  naturally accommodates arbitrary bounds on the metric
completed test exercises) required to qualify an otherwise-non-        durations that separate time points and uses global constraint
specialist to perform the task well. That said, rather than            propagation to calculate earliest and latest possible dates/times
“dumb down” the task, to accommodate non-expert readers, we            for any point (including the beginning and ending points of all
propose to ratchet up annotator performance expectations—to            temporal intervals), as well as tightest bounds on durations.
achieve the highest-quality results possible so that we can drive          This approach also usually affords sufficient global
research regarding extraction of temporal knowledge by                 perspective for a robust recall statistic. Adapting the standard
machines from text to new levels of sophistication. The                approach for evaluating interval relations [11], we can discard
machine reading researchers whose systems are under                    from our gold standard annotations any redundant relations
evaluation quite reasonably ask, before they embark on a               until we determine a set spanning globally calculated bounds.
mission of technological advancement, “Is this task feasible for       Then we can count members of this spanning set whose
humans, with acceptable consistency?” We’d like to answer              addition to a user’s candidate set results in tightening of bounds
that question in the best way that we can.                             in the latter, to determine recall.
                                                                           Only when every member of a set of points is unrelated to
         V. RELATED WORK AND PROPOSED ADVANCES                         the calendar (i.e., we have only point ordering and interval
    Beyond test questions and answers, the entire machine              duration information) do we lack calendar bounds supporting
reading community would benefit from having a large volume             meaningful recall assessment. Then, however, by choosing any
of good temporal logic annotations available. Time is a key            point in a connected set to serve as a reference (in place of the
topic in language understanding, engendering much current              calendar), we can apply the same approach as above.
community interest. TimeML [4], which emphasizes XML                       It may reasonably be argued that at some threshold of
annotation structures rather than RDF ontology and                     representational complexity the brute force transitive closure-
relationships, has been used in the TempEval temporal                  and-spanning tree approach to computing recall and precision
annotation activities (see, e.g., www.timeml.org/tempeval2/)           of an extracted knowledge base (set of statements) must
and advanced as an international standard [5]. We are                  become impractical. Our quantitative temporal statements are
interested in exploring the synergy between this work and ours.        certainly richer than the typical qualitative ones, and
                                                                       (depending on knowledge base size) we may be pushing up
against this threshold with them. Our query answering
evaluation paradigm is more broadly applicable, presuming                                     REFERENCES
inference over extracted statements remains tractable—for the      [1] J. Allen, “Maintaining knowledge about temporal intervals,” in
queries of interest.                                                    Communications of the ACM. 26, pp. 832–843, November 1983.
B. Ascertaining global coherence                                   [2] A. Bittar, P. Amsili, P. Denis, L. Danlos, “French TimeBank: An
                                                                        ISO-TimeML annotated reference corpus,” in Proceedings of the
    Waiting until annotation is done to infer bounds and detect         49th Annual Meeting of the Association for Computational
contradictions neglects opportunities to give annotator’s (e.g.,        Linguistics, pp. 130–134, 2011.
time map-based) feedback and receive their best-effort             [3] L. Ferro, L. Gerber, I. Mani, B. Sundheim, and G. Wilson,
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eliminating incoherencies is an arduous task, and performing            expressions,” MITRE Corporation, 2005.
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this.                                                                   2003.
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                         VI. SUMMARY
                                                                        an international standard for semantic annotation,” in
    We have outlined existing and anticipated future benefits of        Proceedings of the Seventh International Conference on
an end-to-end methodology for…                                          Language Resources and Evaluation (LREC), Malta. May 18-21,
    • Annotating formal RDF statements representing                     2010.
         temporal knowledge to be extracted from text              [6] R. Schrag, J. Carciofini, and M. Boddy, “Beta-TMM Manual
    • Authoring and validating test and/or application                  (version b19),” Technical Report CS-R92-012, Honeywell SRC,
         queries to exercise that knowledge.                            1992.
These capabilities are supported by an implemented temporal        [7] R. Schrag, M. Boddy, and J. Carciofini. “Managing disjunction
reasoning engine. They and the engine are intended to support           for practical temporal reasoning,” in Principles of Knowledge
a timeline tool conceived for use by intelligence analysts. We          Representation and Reasoning: Proceedings of the Third
have explained how these benefits can advance machine                   International Conference (KR-92), pp 36–46, 1992.
reading technology by increasing both sophistication and           [8] R. Schrag, “Best-practice time point ontology for event calculus-
quality expectations about temporal annotations and extraction.         based temporal reasoning,” 7th International Conference on
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                     ACKNOWLEDGMENT                                     (STIDS), 2012.
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    Thanks to other participants in DARPA’s Machine Reading             in the temporal annotation and analysis of text,” Language
research program—especially to other members of the SAIC                Resources and Evaluation v. 39, pp. 243–265, 2005.
evaluation team, including Global InfoTek (the author’s former     [10] M. Shanahan, “The event calculus explained,” in Artificial
employer).                                                              Intelligence Today, ed. M. Wooldridge and M. Veloso, Springer
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