THE TOWL ONTOLOGY LANGUAGE

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• THE TOWL ONTOLOGY LANGUAGE
• Temporal extension to OWL-DL
• Representation of time and temporal information
• Allows for automated reasoning in a temporal
  context
• Concrete domains for the representation of time
  in its quantitative nature (intervals)
• Perdurantist approach for the representation of
  temporal information (change, state transitions)

APPLICATION 1 STOCK WATCHER A web application
that enables the extraction of relevant news
items from RSS feeds concerning the NASDAQ-100
listed companies. The application's goal is to
present a customized, aggregated view of the news
categorized by different topics, while also
giving an assessment of the impact hereof on
stock prices.

• STOCK WATCHER - MAIN FEATURES
• Customizable user portfolio
• Categorization of news items in one of the 4
  available categories company, competitors,
  important people, and primary industry
• Impact assessment of individual news items on
  the stock price of the involved company

Figure 1. TOWL Layer Cake.

• THE TOWL LAYER CAKE
• TOWL is based on a layered approach for the
  addition of temporal expressiveness to OWL-DL
  (Figure 1).
• OWL-DL forms the basis of the current approach
  towards representing time in Web Information
  Systems. As far as static information is
  concerned, TOWL maintains full backwards
  compatibility with OWL-DL.
• Concrete Domains as an extension to OWL-DL enable
  the representation of time. The concrete domain
  employed for the current purpose is the set Q of
  rational number together with the lt and
  predicates. Extending upon OWL-DL, we add to the
  expressive power of the latter by enabling n-ary
  predicates over functional role chains.
• Time Representation relates to enabling temporal
  expressions in the language. In this context, the
  concept of time is employed to refer to
• Representations of time in the form of instants
  and intervals
• Representation of Allens 13 interval relations
• The representation of Allens 13 interval
  relations is enabled by a translation of these
  predicates in terms of elements of the domain Q
  of the concrete domain and its 2 predicates lt
  and .
• Timeslices/Fluents stand at the fundament of our
  approach for representing temporal information.
  The main components of temporal information in
  the current context relate to
• Representing change
• Representing state transitions
• The approach employs timeslices for representing
  temporal parts of an individual over certain time
  intervals while fluents indicate the changing
  aspect(s) across those intervals.

Figure 2. Stock Watcher Output.
APPLICATION 2 CONSENSUS AGGREGATOR The Consensus
Aggregator system is built to support two main
processes i) the process of gathering and
storing market advices given by brokers, and ii)
the process of aggregating market advices into a
single advice.

• CONSENSUS AGGREGATOR - MAIN FEATURES
• Basic temporal reasoning regarding the temporal
  validity of individual advices
• Using historical information for determining the
  performance of individual brokers
• Advanced methods for taking into account
  individual brokers experience in specific sectors

Figure 3. Consensus Aggregator Performance.
ACKNOWLEDGEMENT The authors are partially
supported by the EU funded IST STREP Project
FP6-26896 Time-determined ontology-based
information system for real-time stock market
analysis (TOWL). More information is available on
the official website of the TOWL project
(http//www.towl.org/).