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Homepage: http://www.cs.indiana.edu/~tdevadit

Blog
2/20/2007

Data Models

Data Models
  • Graph
    - DBMS with graph data model for knowledge handling (link)
  • E-R Model - Wikipedia
    - The entity-relationship model—toward a unified view of data (link)
  • Network Model - Wikipedia
    - Network (CODASYL) Data Model (link)
  • XQuery and XPath data model (link) 
CLASSIC: a structural data model for objects (link)
 
Wikipedia - Data Models (link) and Data Modelling (link)
 
Database Models - Wikipedia (Unixspace)
 
Data Modeling 101 (link)
 
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12/25/2006

Fedora Setup

These tips are mainly for installing applications that are not open source. For most of the open source applications, FC package manager, Yum will do the job.

Personal Fedora Core 6 Installation Guide (link)
Sun J2SDK-1.5 on Fedora Core 5 and 6 (FC5 and FC6) (link)

How to make fonts on Fedora Core 6 look like on Microsoft Windows (link)

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12/23/2006

Doxygen

Create a configuration file
doxygen -g <config-file>
If <config-file> is not given, the default is Doxyfile.
The generated file has configuration parameters. Most of them have comments and are self explanatory. Some parameters that need to be modified are,
  • PROJECT_NAME
  • OUTPUT_DIRECTORY
  • REPEAT_BRIEF
    - If YES, prepends the brief description of a member or function before the detailed description.
  • EXTRACT_ALL
    - If YES, all entities in the documentation are documented, even if no documentation was available.
    - Warnings about undocumented members will not be generated as long as this is set to YES.
  • INPUT
    - List of directories containing source files.
    - If left blank, the current directory will be used.
  • RECURSIVE
    - If YES, processes sub-directories recursively.
  • SOURCE_BROWSER
    - If YES, generates cross-reference a (documented) entity with its definition in the source files.
  • GENERATE_HTML, GENERATE_LATEX
Most of the others can be left with their default values.
Examples of documeting the code can be found at, http://www.stack.nl/~dimitri/doxygen/docblocks.html.
Running doxygen
doxygen <config-file>
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12/20/2006

Concepts Related to RDF

Semi-Structured Data - Peter Wood
Description Logic - Course Notes
Sub-graph Isomorphism Problem (distributed)
 
RDF Vs. XML
  • XML and RDF (blog)
  • Why RDF model is different from the XML model (link)
    - In XML, there are many ways to represent something like "The author of the page is Ora". In RDF, there is only one way.
    - While all the different ways may convey some meaning for the human reader, it will not be the case for a computer.
    - Querying in XML is more complex due to many ways of representing the same thing.
    - Mapping from XML to RDF is many-to-one.
  • Using XML for Data (link)
    - An XML document can't have disjoint parts and therefore XML doesn't map 1-1 with a directed, labeled graph.
  • Is RDF/XML Good for Anything? (link)
    - XML is designed to describe trees. RDF/XML is a transfer syntax for graphs.
What the Semantic Web can represent (link)
  • The Semantic Web and Entity-Relationship models
    - RDF is similar to E-R model except that relationships are first class objects in RDF.
    - In RDF, the set of slots of an object is not defined when the class of an object is defined.
  • The Semantic Web and Relational Databases
    - In DB, a query can join tables by any comlumns which match by datatype.

 SPARQL Vs. RDQL

  • From RDQL to SPARQL (blog) 
Advantages of SPARQL
  • Supports named graphs - query contains a FROM clause to specify the graph
  • Supports queries with typed literals
  • Sort results
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Ontologies

 
Misconceptions about OWL Reasoning - Harry Chen
... this classification could create misconceptions that lead people to wrongly interpret the properties of different OWL reasoning. For example, a common belief is that when you build an ontology, you should attempt to stay within OWL-DL because OWL-DL reasoners is more efficient that OWL-Full reasoners. Some others believe that the use of OWL-Full will always cause intractable computation performance in a reasoner.
 
...just because a system is undecidable does not mean that it is useless. Turing complete languages (such as Java or C) are not guaranteed to complete (while(true) {...}) and yet these languages are still quite useful. Programmers just have to be careful that their constructs terminate.
 
 
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