Problems
Emerging Science of the Internet: Some New Opportunities (Ron Brachman, Yahoo)
This article is a free writing from the last keynote speaker, Ron Brachman, from Yahoo. I write any ideas during the presentation, which reader might find not complete or structured. Anyway.. enjoy this note.
Knowledge Representation (KR) is a very important ingredient for the semantic web movement. And in the Semweb, KR meets the Web. Semweb can be said as "addding logic to the Web."
Ron's thought is that Semantic Web is now transforming the industry. He explained why Yahoo needs the SW, why KR is great, and how we can get profit wildly. However, major web company seem to take different direction.
Maven error: Cannot find parent
Reference: Maven Getting Started
First time I run Maven with this command:
fahmi@evans:~/workspace/swhi/WebContent$ mvn archetype:create -DgroupId=rug.swhi -DartifactId=swhi -Dpackaging=war
I got the following error:
Downloading: http://repo1.maven.org/maven2/org/codehaus/plexus/plexus-container-default/1.0-alpha-7/plexus-container-default-1.0-alpha-7.pom 1K downloaded Downloading: http://repo1.maven.org/maven2/plexus/plexus-containers/1.0.2/plexus-containers-1.0.2.pom 471b downloaded [INFO] ------------------------------------------------------------------------
Eclipse: Committing generated class files
I use Eclipse and Subversion for this project. I can commit the modified java files, but am unable to commit the generated class files. From the package perspective of the Eclipse, I cannot see the WEB-INF/classes directory. Therefore I cannot select and commit the class files manually.
There is no .svn directories in packages under the WEB-INF/classes directory.
It is true, because:
Which files should NOT be added to CVS?
By comparision, the following files should NEVER be added to CVS:
Problem: inferencing gone mad
The last few days I have been trying to fix a problem. I finally got inferencing working, see my previous post, however, it seems to go mad for some concepts. I am not sure what is causing this. I have been trying to track the problem, but I do not see it. So what is the problem?
In SeRQL you can select all direct instances of a concept. I was trying to formulate a query to retrieve the 82 Event instances. You can do this using the serql:directType function. So you would think that this simple query would do the trick:
SELECT Event
FROM {} serql:directType {swhi:Event};
Loading ontology into Sesame (error: exceeded)
SESAME : http://evans.ub.rug.nl:8080/sesame/
Login: testuser
pass: opensesame
Loading Vicode RDF into Sesame:
http://evans.ub.rug.nl/~fahmi/vicodi/vicodi.rdf
Transaction started...
Status:
Loading dataStatus:
Data loaded (12,591,803 bytes)Status:
Checking data for errorsError:
error while adding new triples: org.openrdf.rio.ParseException: org.xml.sax.SAXParseException: The parser has encountered more than "64,000" entity expansions in this document; this is the limit imposed by the application.Transaction finished
PostgreSQL: FATAL IDENT authentication failed
Everytime I log in using normal user, I got this message:
$ psql -U gateadmin template1
psql: FATAL: IDENT authentication failed for user "gateadmin"Why?
It looks like you would rather use password authentication than the
default IDENT-based auth (it's default in Debian distro of postgres
anyway). IDENT will only let you in when you do *not* use -U, ie,
your postgres user name is the same as your Unix user name. Change
this in pg_hba.conf, and don't forget to SIGHUP or restart the
postmaster afterwards.
regards, tom lane
Solution:
Just modify pg_hba.conf like this (change to trust)
How to refresh jsp cache?
The page generated by Sesame seems cached. Although the database has been changed, the same cache will be delivered. How to release the cache and generate new page?
Anytime I want to get a change on my page, I have to restart the Tomcat server.
This piece should help:
From http://www.oreillynet.com/cs/user/view/cs_msg/4988
Much has been written about servlet caching in Tomcat, but I don't see a solution out there. I have tried the following code :
response.setHeader("Cache-Control", "no-cache");
response.setHeader("Pragma", "no-cache");
But I believe this code effects browser cache and not the cache of the servlet engine itself.
Problem running Kowari 1.0.5: Bad generated URI
I got the following error in running Kowari 1.0.5 on my server at home (Drupal)
fahmi@cc653097-a:/opt/kowari-1.0.5/dist$ sudo java -jar kowari-1.0.5.jar
Kowari Metadata Store version 1.0.5 (Build v1.0.831)
INFO [main] (?:?) - RMI Registry started automatically on port 1099
1 [main] INFO org.kowari.server.EmbeddedKowariServer - RMI Registry started automatically on port 1099
INFO [main] (?:?) - java.security.policy set to jar:file:kowari-1.0.5.jar!/conf/kowari-rmi.policy
196 [main] INFO org.kowari.server.EmbeddedKowariServer - java.security.policy set to jar:file:kowari-1.0.5.jar!/conf/kowari-rmi.policy
Kowari: Problem executing Descriptor
Action: Accessing http://glo-druiven2.ub.rug.nl:8080/webservices/descriptor/
Error: Redirection limit for this URL exceeded. ...
Solving limitations in the Qualified Dublin Core
The RDF output of the Evans metadata generated by the MarcEdit is unqualified. Refinement into the Qualified Dublin Core faces several problems caused by the limitation of the QDC it self.
Creator
Works or objects expressed in the Evans metadata contain information about authors and their life periods. For example, "Gardiner, John Sylvester John" had a date period of "1765-1830".
How can we express this information using the Qualified Dublin Core in RDF/XML? Let see what the QDC provides for the creator element. The QDC document shows no element refinement for the creator element.
