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  <title>Toward proof exchange in the Semantic Web</title>
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<div class="slide">
<h1>Toward proof exchange in the Semantic Web</h1>


<address class="vcard" id="danc" style="text-align:center">
<a class="url fn n foaf-name" rel="foaf-homepage" href="http://www.w3.org/People/Connolly/"><span class="given-name">Dan</span
> <span class="family-name">Connolly</span></a><br />

<img src="http://dig.csail.mit.edu/~lkagal/ai-web/images/dig-logo.gif" alt="DIG LOGO" height="25"/><br />

<span class='org'>
<a class="organization-unit"
href="http://dig.csail.mit.edu/">Decentralized Information
Group</a><br />
<span class="organization-name">
MIT Computer Science and Artificial Intelligence Laboratory</span>
</span>

</address>

  <div class="vevent" id="_4877_aus200609" style="text-align: center">
    <cite><a class="summary url"
    href="http://www.cs.utexas.edu/users/moore/acl2/seminar/index.html">ACL2 Seminar</a></cite><br />

    <abbr class="dtstart" title="2006-09-13">
    September 13, 2006</abbr>, <b class="location"><abbr class="geo"
    title="30.300474;-97.747247"><a
    href="http://en.wikipedia.org/wiki/Austin%2C_Texas">Austin,
    TX</a></abbr></b>
  </div>

<br />
<br />
<hr />
<div class="footnote"><em>postscript: <a
href="http://dig.csail.mit.edu/breadcrumbs/node/160">breadcrumbs weblog item
September 16</a></em></div>

</div>

<div class="background">
<img id="head-logo-fallback" alt="CSAIL Logo" src="http://dig.csail.mit.edu/~lkagal/ai-web/images/csail-logo-grad.gif"/>
</div>


<div class="slide"><h1>Policy Aware Web (PAW) Project</h1>

<ul>
<li>Abstract:
<blockquote>

<p>In this paper, we describe the motivations for, and development of,
a rule-based policy management system that can be deployed in the open
and distributed milieu of the World Wide Web. We discuss the necessary
features of such a system in creating a "Policy Aware" infrastructure
for the Web, and argue for the necessity of such infrastructure. We
then show how the integration of a Semantic Web rules language (N3)
with a theorem prover designed for the Web (Cwm) makes it is possible
to use the Hypertext Transport Protocol (HTTP) to provide a scalable
mechanism for the exchange of rules and, eventually proofs, for access
control on the Web. We also discuss which aspects of the Policy Aware
Web are enabled by the current mechanism and describe future research
needed to make the widespread deployment of rules and proofs on the
Web a reality.
</p>


  <cite class="inbook" id="paw2006">
    <span class="author">Daniel Weitzner</span>,
    <span class="author">Jim Hendler</span>,
    <span class="author">Tim Berners-Lee</span>,
    and <span class="author">Dan Connolly</span><!-- = me@@ -->.
    <cite><a href="http://www.mindswap.org/users/hendler/2004/PAW.html"
	     >Creating a policy-aware web: Discretionary, rule-based
    access for the world wide web</a></cite>. In Elena Ferrari and Bhavani
    Thuraisingham, editors, <cite>Web and Information Security</cite>.
    <a href="http://www.irm-press.com">IRM Press</a>, 2006.
  </cite>
</blockquote>
</li>

<li>A collaboration between the University of Maryland Mindswap
(Hendler, ...) and DIG (Weitzner, Berners-Lee, Connolly, ... )</li>
<li><a href="http://www.policyawareweb.org/">policyawareweb.org</a></li>
<li>Funded under <a
href="http://www.nsf.gov/pubs/2004/nsf04012/nsf04012.htm">NSF ITR
04-012</a></li>
</ul>

</div>

<div class="slide"><h1>A PAW scenario: access to girl scout event photos</h1>

<p>Current working <a href="http://dig.csail.mit.edu/2005/09/rein/examples/">some PAW examples</a> include:</p>

<blockquote>
<p>The <a
href="troop42-policy.n3">troop policy</a> is:</p>

<ol>
   <li> Photos taken at meetings of the troop can be shared with any
current member of the troop.</li>

   <li>Photos taken at a jamboree can be shared with anyone in the
troop or with anyone who attended the jamboree.</li>

   <li>Photos of the girls winning awards can be shared with anyone
currently in the troop, or who was ever a member. These award photos
can also be shared with the public if, and only if, the girl's parents
allow it.</li>
</ol>

</blockquote>

<p>For more, see:</p>
<ul class="bibliography">
  <li id="aaai06paw" class="inproceedings">
    <span class="author">Lalana Kagal</span>, <span class="author">Tim
    Berners-Lee</span>, <span class="author">Dan Connolly</span>, and
    <span class="author">Daniel Weitzner</span>, <cite><a
    href="http://dig.csail.mit.edu/2006/Papers/AAAI/">Using Semantic
    Web Technologies for Open Policy Management on the Web</a></cite>,
    <span class="booktitle">21st National Conference on Artificial
    Intelligence</span> (<a
    href="http://www.aaai.org/Conferences/AAAI/aaai06.php">AAAI
    <span class="year">2006</span></a>), with
    <a href="http://dig.csail.mit.edu/~lkagal/ai-web/">talk slides</a>
  </li>
</ul>

</div>

<div class="slide"><h1>Transparent Accountable Datamining Initiative (TAMI) Project</h1>

<ul>
<li>
<blockquote>
<p>The TAMI Project is creating technical, legal, and policy foundations
for transparency and accountability in large-scale aggregation and
inferencing across heterogeneous information systems. The
incorporation of transparency and accountability into decentralized
systems such as the Web is critical to help society manage the privacy
risks arising from the explosive progress in communications, storage,
and search technology. The expansion of government use of large-scale
data mining for law enforcement and national security provides a
compelling motivation for this work. While other investigations of the
impact of data mining on privacy focus on limiting access to data as a
means of protecting privacy, a variety of social, political, and
technical factors are making it increasingly difficult to limit
collection of and access to personal information. The TAMI Project is
addressing the risks to privacy protection and the reliability of
conclusions drawn from increasing ease of data aggregation from
multiple sources by creating methods and technologies for adding
increased transparency and accountability of the inferencing and
aggregation process itself. The project is developing precise rule
languages that are able to express policy constraints and reasoning
engines that are able to describe the results they produce.
</p>
</blockquote>
</li>
<li>Weitzner, Abelson, Berners-Lee, Hanson, Hendler, Kagal, McGuinness, Sussman, Waterman, <cite>Transparent Accountable Data Mining: New Strategies for Privacy Protection</cite>,; MIT CSAIL Technical Report MIT-CSAIL-TR-2006-007
</li>

<li>working with <a
href="http://iw.stanford.edu/2.0/">InferenceWeb</a> project
(McGuiness, ...) at Stanford</li>

<li>supported by the US National Science Foundation <a href="http://www.nsf.gov/pubs/2005/nsf05518/nsf05518.htm">Cybertrust (05-518)</a> program.</li>
<li>... <a href="http://dig.csail.mit.edu/TAMI/">TAMI web page</a></li>
</ul>
</div>

<div class="slide"><h1>A TAMI scenario: </h1>

<blockquote>

<p>Adverse actions premised on inferences from data where the data,
while factually correct and properly in possession of the user, is
used for an impermissible purpose.</p>

<p>TSA finds a possible name match (of a very common name) between a
person in a Passenger Name Record and a person in the Terrorist
Screening DataBase and properly sends the information to the FBI. The
FBI arrests him for unpaid child support under the federal "Deadbeat
Dad" statute. This will turn out to be impermissible because:</p>

<ol type="a">
<li>the SORN says the purpose of collecting Passenger Name Record information is "to enhance the security of domestic air travel by identifying only those passengers who warrant further scrutiny" and</li>

<li>the Privacy Act requires USPerson data to be used only for the purposes for which it was collected.</li>
</ol>
</blockquote>

</div>

<div class="slide"><h1>Semantic Web Basics</h1>
<ul>
<li>What is the Semantic Web?
<ul>
 <li>Data integration across application, organizational boundaries</li>
</ul>
</li>
<li>How does it work?
<ol>
<li>Apply power of URIs to concepts of relational data
<ul>
<li>Don't say "colour" say &lt;http://example.com/2002/std6#col></li>
</ul>
</li>
<li>Model real things, not just documents or database tables</li>
</ol>
</li>
</ul>
</div>

<div class="slide"><h1>Logic, Databases, and Scale</h1>

<table border="1" class="compare">
<tr><td>&#160;</td><th>Web</th><th>Semantic Web</th></tr>
<tr><th>Traditional Design</th><td>hypertext</td><td>logic/database</td></tr>
<tr><th>+</th><td colspan="2">URIs</td></tr>
<tr><th>-</th><td>link consistency</td><td>?</td></tr>
<tr><th>=</th><td colspan="2">viral growth</td></tr>
</table>
<p>Are there parts of traditional logic and databases that, if we set them
aside, will result in viral growth of the Semantic Web?</p>
</div>

<div class="slide"><h1>Semantic Web standards and research</h1>

<img src="http://www.w3.org/DesignIssues/diagrams/SemWave.png" alt="semantic web topics and their status, research to standards to deployment"/>

<p><a href="http://www.w3.org/2003/Talks/01-siia-tbl/slide1-0.html">Berners-Lee, Jan 2003</a></p>
</div>


<div class="slide"><h1>Semantic Web Atomic Formulas</h1>

<p><img alt="arrow tail, body and head are l are subject, property and value." src="http://www.w3.org/DesignIssues/diagrams/spv-arrow.png" /></p>

<ul>
  <li>The Resource Description Framework (RDF)
  <ul>
    <li>abstract syntax, formal semantics</li>
    <li>standard encoding in XML</li>
    <li>emerging programmer-friendly short-hand encoding: <a href="http://www.w3.org/2000/10/swap/Primer.html">N3</a>/<a href="http://www.dajobe.org/2004/01/turtle/">turtle</a>
    </li>
  </ul>
  </li>

</ul>
<p>Note the relationship to HTML links, especially with the
re-discovery of the <tt>rel</tt> attribute in <a
href="http://microformats.org/">microformats</a>: vote-for, friend,
etc..</p>
</div>

<div class="slide"><h1>Semantic web includes tables, trees...</h1>

<p><img alt="Arrows can make a table, an arrow from each row to each value"
 src="http://www.w3.org/DesignIssues/diagrams/arrow-table.png" /></p>

<p><img alt="Arrows can make a table, an arrow from each row to each value"
 src="http://www.w3.org/DesignIssues/diagrams/tree.png" /></p>

</div>

<div class="slide"><h1>... and tangly messes</h1>

<p><img alt="Arrows can make a table, an arrow from each row to each value"
src="http://www.w3.org/DesignIssues/diagrams/tree-and-table2.png" /></p>

</div>

<div class="slide"><h1>RDF Terms: URIs, literals, existentials</h1>

<ul>
<li>string literals, integer literals:
<pre>
MyConf conf:eventName "WWW2006 Workshop on Models of Trust for the Web".
MyConf conf:numOfRegistrants 65.
</pre>
</li>

<li>existentials:
<pre>
  @forSome X. j:Joe foaf:knows X. X foaf:name "Fred" .

  j:Joe foaf:knows [ foaf:name "Fred" ] .
</pre>
</li>

  <li>
    <a href="http://www2003.org/">The Twelfth International World Wide
    Web Conference</a>, Budapest HUNGARY, May 2003; <cite><a
    href="http://www.w3.org/2000/10/swap/doc/">Semantic Web Tutorial
    Using N3</a></cite> with Sandro Hawke and Tim Berners-Lee
  </li>

<li>Dave Beckett, <cite><a
href="http://www.dajobe.org/2004/01/turtle/">Turtle - Terse RDF Triple Language</a></cite>, work in progress 2004-2006
<p>This is an N3 subset
that corresponds to the RDF/XML standard.</p>
</li>
</ul>
</div>

<div class="slide"><h1>RDFS and OWL Standards</h1>

<p>RDF Schema (RDFS) and the Web Ontology Language (OWL) correspond to
UML notions such as subclass, domain, range, cardinality, etc.</p>

<img align="right"
     src="http://www.w3.org/2000/10/swap/pim/travelFig.png"
     alt="travel concepts schema" />

<ul>
<li style="color: red;">cyc terms  in red</li>
<li style="color: purple;">DAML airport ontology terms in purple</li>
<li style="color: green;">custom travelTerms in green.</li>
<li style="color: blue;">RDF standard terms in blue</li>
<li style="color: orange;">XML Schema terms in orange</li>
</ul>

</div>

<div class="slide"><h1>SQL * URIs = SPARQL</h1>

<p>Aggregate data from friends etc, then...</p>
<img align="right"
     src="http://www.w3.org/DesignIssues/diagrams/spv-table.png"
     alt="table subject/property/value" />

<pre>
  PREFIX foaf: &lt;http://xmlns.com/foaf/0.1/>
  PREFIX c: &lt;http://www.w3.org/2002/12/cal/icaltzd#>
  SELECT ?name, ?summary, ?when
   FROM &lt;myFriendsBlogsData>
   WHERE { ?somebody foaf:name ?name; foaf:mbox ?mbox.
           ?event c:summary ?summary;
                  c:dtstart ?ymd;
                  c:attendee [ c:calAddress ?mbox ]
         }.
</pre>

<table border="1">
<tr><th>?name</th><th>?summary</th><th>?when</th></tr>
<tr><td>Tantek Çelik</td><td>Web 2.0</td><td>2005-10-05</td></tr>
<tr><td>Norm Walsh</td><td>XML 2005</td><td>2005-11-13</td></tr>
<tr><td>Dan Connolly</td><td>W3C tech plenary</td><td>2006-02-27</td></tr>
</table>

<p>See <cite><a href="http://www.w3.org/TR/rdf-sparql-query/">SPARQL
Query Language for RDF</a></cite> W3C Working Draft 21 July 2005</p>
</div>

<div class="slide"><h1>N3 Rules</h1>

<pre>
@keywords is, of, a.
@prefix : &lt;#>.

socrates a Man.
{ ?who a Man } => { ?who a Mortal }.
</pre>
</div>

<div class="slide"><h1>Reminder: we're using URIs</h1>

<pre>
socrates a Man.
</pre>

<p>abbreviates</p>

<pre>
&lt;#socrates> &lt;http://www.w3.org/1999/02/22-rdf-syntax-ns#type> &lt;#Man>.
</pre>
</div>


<div class="slide"><h1>Standard terms for idioms</h1>

<p>We can say this much using just the RDF/RDFS standards:</p>

<pre>
socrates a Man.
Man rdfs:subClassOf Mortal.
</pre>

<p>And then we can implement the standard RDFS semantics with rules:</p>

<pre>
@prefix rdfs: &lt;http://www.w3.org/2000/01/rdf-schema#> .

{ ?X a [rdfs:subClassOf ?C] } => { ?X a ?C }.
</pre>

</div>

<div class="slide"><h1>A proof</h1>

<ul>
<li><tt>python cwm.py socrates.n3 --think --why >socrates-pf.n3</tt></li>
<li><tt>python check.py socrates.n3 socrates-pf.n3</tt>
<pre>
1: ... [by parsing &lt;socrates.n3>]

2: :socrates a :Man .
 [by CE on 1]

3: @forAll :who . { :who a :Man . } log:implies {:who a :Mortal . } .
 [by CE on 1]

4: ...
 [by GMP on 3, [2]]

5: @forAll :who . :socrates a :Man, :Mortal . { :who a :Man . } log:implies {:who a :Mortal . } .
 [by CI on [1, 4]]
</pre>
</li>
</ul>

</div>

<div class="slide"><h1>Using web access and quoting to express policies</h1>

<ul>
<li>Policy: if someone's home page says that they are a vegetarian,
then we believe that they are a vegetarian.</li>

<li>
<pre>
@prefix foaf: &lt;http://xmlns.com/foaf/0.1/>.
@prefix log: &lt;http://www.w3.org/2000/10/swap/log#> .

@forAll WHO.

{ WHO foaf:homepage ?PG.
 ?PG log:semantics [ log:includes { WHO a Vegetarian } ]
} => { WHO a Vegetarian}.
</pre>
</li>
</ul>
</div>

<div class="slide"><h1>Expressing policies (cont)</h1>

<ul>
<li>Conference organizers set up <tt>conf_reg_ex.n3</tt>:
<pre>
@forAll WHO.

{ WHO foaf:homepage ?PG.
 ?PG log:semantics [ log:includes { WHO a Vegetarian } ]
} => { WHO a Vegetarian}.

&lt;joe_profile.n3#joe> foaf:homepage &lt;joe_profile.n3>.
</pre>
</li>
<li>Joe writes, in <tt>joe_profile.n3</tt>:
<pre>
&lt;#joe> foaf:homepage &lt;>; a Vegetarian.
</pre>
</li>
</ul>
</div>

<div class="slide"><h1>A proof using the Vegetarian policy</h1>

<ul>
<li><tt>python cwm.py conf_reg_ex.n3 --think --why >,veg-pf.n3</tt></li>
<li><tt>python check.py ,veg-pf.n3</tt>
<pre>
1: ...
 [by parsing &lt;conf_reg_ex.n3>]

2: :joe &lt;http://xmlns.com/foaf/0.1/homepage> &lt;file:/Users/connolly/w3ccvs/WWW/2000/10/swap/test/reason/joe_profile.n3> .
 [by CE on 1]

3: &lt;file:/Users/connolly/w3ccvs/WWW/2000/10/swap/test/reason/joe_profile.n3> log:semantics {joe:joe a :Vegetarian; &lt;http://xmlns.com/foaf/0.1/homepage> &lt;file:/Users/connolly/w3ccvs/WWW/2000/10/swap/test/reason/joe_profile.n3> . } .
 [by built-in Axiom log:semantics]

4: { joe:joe a :Vegetarian; &lt;http://xmlns.com/foaf/0.1/homepage> &lt;file:/Users/connolly/w3ccvs/WWW/2000/10/swap/test/reason/joe_profile.n3> . } log:includes {joe:joe a :Vegetarian . } .
 [by built-in Axiom log:includes]

5: @forAll :WHO, con:PG . { @forSome foo:_g3 . foo:_g3 log:includes {:WHO a :Vegetarian . } . :WHO &lt;http://xmlns.com/foaf/0.1/homepage> con:PG . con:PG log:semantics foo:_g3 . } log:implies {:WHO a :Vegetarian . } .
 [by CE on 1]

6: ...
 [by GMP on 5, [2, 3, 4, 4]]

7: @forAll :WHO, con:PG . joe:joe a :Vegetarian; &lt;http://xmlns.com/foaf/0.1/homepage> &lt;file:/Users/connolly/w3ccvs/WWW/2000/10/swap/test/reason/joe_profile.n3> . { @forSome foo:_g3 . foo:_g3 log:includes {:WHO a :Vegetarian . } . :WHO &lt;http://xmlns.com/foaf/0.1/homepage> con:PG . con:PG log:semantics foo:_g3 . } log:implies {:WHO a :Vegetarian . } .
 [by CI on [1, 6]]
</pre>
</li>
</ul>
</div>

<div class="slide"><h1>Related Work</h1>

<ul>
<li>InferenceWeb's proof browser can browse these proofs, using a conversion to PML</li>
<li>Jos DeRoo's Euler backward-chainer produces proofs that interoperate with chek.py</li>
<li>log:semantics is similar to the knowledge function, K, in
<ul class="bibliography">
<li id="pan06a" class="inproceedings">
<span class="author">Z. Pan and A. Qasem and J. Heflin</span>
<cite><a href="http://swat.cse.lehigh.edu/pubs/index.html#pan06a">An Investigation into the Feasibility of the Semantic Web</a></cite>. In <span class="booktitle">Proc. of the Twenty First  National Conference on Artificial Intelligence  (AAAI 2006)</span>, <span class="address">Boston, USA</span>, <span class="year">2006</span> (<a href="http://swat.cse.lehigh.edu/pubs/abstracts06.html#pan06a">abstract</a>)
</li>
</ul>
</li>

</ul>
</div>

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