Category Archives: UniSA

Intern News

At the end of the fourth week in Adelaide a short recall of topics:

Linux

Debian:

  • server setup, port configuration, JAVA application deployment
  • services: apache2, SSH, webmin, firestarter
  • configuration of sudoers, proxy configuration;
  • issues with blocking site partially solved with increasing time between requests (other options: running several instances of the application, randomize requests);
  • moved to server room, up and running.

Ubuntu:

  • desktop GUI setup;
  • Oracle setup following an excellent tutorial on http://www.pythian.com/blogs/968/installing-oracle-11g-on-ubuntu-804-lts-hardy-heron A tricky part was the creation of a database using dbca. All wizard steps where pretty smooth. There were no errors at all. But the last screen of the wizard just showed a Grey window without any buttons, so the process couldn’t be completed. Problem solved with disabling all visual effects in Ubuntu (System->Preferences->Appearance->Visual Effects->’None’);
  • without a startup script, the $ORACLE_SID has to be set to the database name before connecting with SQL Plus: export ORACLE_SID=dbname
  • connect to database using command history recall (‘Up’-Key): rlwrap sqlplus username

Commands: sed, cp, mv, nc, ssh, dhclient, ifconfig,…

Databases

Oracle

  • played with several SQL statements and PL/SQL procedures to determine relationship between queries and documents, starting with (query, doc1, doc2) triples. Each triple represents a graph; the graphs connected result in a ‘forest’ which can then be explored (emergent semantics);
  • wrote documentation

PostGres

As we’re running Macs in our Lab, we’d like to keep the TimeMachine funcionality on the Mac Pro where the database is going to run. Therefore, no Linux. In fact, there’s no Oracle 11g server distribution for MacOS. As we won’t need Oracle’s Spatial functionality like we thought before, we might port to PostGres.

Oracle – PostGres differences

Oracle PostGres
VARCHAR2(n) no VARCHAR2(n), use VARCHAR(n) instead
no autoincremention, use triggers instead auto incrementation data type SERIAL4
sequence.NEXTVAL, sequence.CURRVAL
  • nextval(‘sequence’)
  • currval(‘sequence’)
  • lastval (returns value most recently obtained)
  • setval(‘sequence’, bigintvalue)
PL/SQL unique constraint exception DUP_VAL_ON_INDEX UNIQUE_VIOLATION
RETURN RETURNS
DROP FUNCTION fname; DROP FUNCTION fname(TYPE, TYPE,…);
EXEC fname(arg1, arg2,…); SELECT fname(arg1, arg2,…);
Before creating a function: CREATE LANGUAGE plpgsql; define to use this language in function header: … RETURNS void AS $$ DECLARE …; after function creation: $$ LANGUAGE ‘plpgsql’;
DESC tablename; \d tablename;
START script.sql; \i script.sql;
Start client from command line: rlwrap sqlplus username sudo -u user psql database
Exit command line: exit \q
Show user tables: select table_name from user_tables; \dt

Debian and Future Tasks

Work diary, second week:

The Debian server is almost ready to go. Managed to get Apache2 with phpWiki running this week. Reminder: Always delete every other Apache installation. And: Watch out for existing log dirs when setting up a VirtualHost (entries have to be the same as in filesystem).

Set up Webmin, a great webinterface for Linux systems. You can manage almost everything: Apache server, MySQL server, processes, etc… from remote. Disabled automatic boot startup and changed port for Webmin. SSH works great.

Main application is running, although it seems to have still some problems with particular sites.

Future tasks: Discussed goals with Helen. As soon as the server setup is finalized and the application runs smoothly, the system is going to move (still open: try .sh scripts, port from Mac to Debian; access from only within the Lab network?). Subsequently, based on the image retrieval project I outlined in another post, I’m going to rebuild the experiment and do research in a new direction.

Linux and Living in a community

Firstly, thanks to everybody who messaged or called me on my new mobile. Actually, I missed most calls and can’t write back. I still don’t have any credit.

The last two working days of last week I spent with some papers and an old workstation, trying to get Debian (Linux) installed and prepared for server use. That worked out pretty well, although the Internet connection had to be established manually today. After a modification of the .bashrc with two additional lines for the HTTP and FTP proxy, almost everything was done. Tomorrow I’m going to get the Sun Java Runtime Environment installed and the firewall configured. This particular machine is ment to be the system for a Java application, which is going to gather information about particular Internet services over the next six months. Afterwards the gathered information is going to be analyzed. Next tasks maybe to write a user documentation, get the application installed and ready to run and take care that it keeps running.

For the last weekend I didn’t have any plans so I stayed in my bed almost the whole Saturday sleeping, watching films, setting up a fresh Windows XP and regenerating. I didn’t feel healthy anyway. But staying at home really paid off. On Sunday I felt so much better. And today my cold is almost gone!

Some words about “living in a community”: I remember those days, back at home when there were people (particularly parents) cleaning up for me when I messed up something or “forgot” to put my dishes into the dishwasher. For me, those sweet days are gone for more than a year and I’m fine. But it seems like some of my housemates still need someone, who cleans up after them. There were some serious kitchen cleaning issues the days before my arrival, they got almost physical. Therefore, a house meeting has been issued for last Sunday, were everybody agreed to a key point: Immediate clean up after kitchen use, including fat splatter and similar. In fact, the days right after the meeting, some just ignored what everybody agreed on. As a result, the former kitty manager wrote a very emotional mail to the landlord, mentioning names and informing him about the situation. That lead to some emotional reactions by the mentioned guy, who was supposed to be the “bad guy”… Anyway, with the beginning of September, I’m the new kitty manager, and therefore responsible for our cash, buying general stuff like toilett paper, reminding others to take care of a clean environment and keep the landlord informed if necessary. I’ll try to avoid that, and personally talk to everybody before doing anything else. And today, the kitchen was perfectly cleaned, anyway.

Finally, some pictures from inside the house.

chair, bed, commode

My room: chair, bed, commode

cabinet, chair, desk

My room: cabinet, chair, desk

big window

My room: big window

Favorite bathroom

Favorite bathroom

Kitchen

Kitchen

Dining table, living area in the background

Dining table, living area in the background

Community area outside, car ports across

Community area outside, car ports across

Washing room, big dustbins outside

Washing room, big dustbins outside

Projects

So what’s going on at the Security Laboratory I’m working for? A major project is summarized below, another one is currently too sensitive for publication.

Search engines: The problem of lexical ambiguity

This summary is based on [1].

Problems may occur, when search queries consist of words, which have more than one meaning. For example, Gavin the gardener tries to find pictures or information about apples (fruit) using the search term ‘apple’. Google will deliver two result pages exclusively with information about the company Apple (computers). Gavin never heard of a company called Apple before. That was not he was looking for. When looking for pictures, it gets a bit better, although there’re still more than half of the pictures related to the company.

To understand those results, one should understand the PageRank algorithm. Google works with the opinion of the mass. Someone puts a link to a certain website S on his own website. Now, the more people put a link to S on their own website, the higher Google rates the relevance and importance of S in a certain search context.

So obviously, a lot of people are linking to Apples (company) or related sites. (In fact, the ranking might also depend on some marketing aspects. Are companies paying for higher rankings?). One couldn’t say the delivered search results are wrong. They just don’t match with what Gavin had in mind when he searched ‘apple’. Moreover, Gavin never heard of the company Apple before, gives up crawling through the result pages after the third one.

How to deal with that problem? As we figured out, to humans ‘apple’ has at least two meanings. Therefore, some sort of classification should be applied. And why don’t we use the opinion of the mass again? A ‘Co-active intelligence’ system, as PageRank is, tries to address this issue. They rely on user-generated information. So why don’t we collect user-information concerning different meanings of certain search terms? Assuming every search session addresses only a certain meaning of a word or combination of words, based upon the collected user interaction information we can build up a collection of classes that are logically connected to specific search terms.

For example, Gavin searches for ‘apple’ with the fruit in mind. The search engine delivers certain result pages. Gavin chooses several pages, pictures, … The search engine now internally connects the search query with the selected pages, assuming that Gavin knows, which pages, images, … fit best for the query. The more people participate, the more accurate results will get. Users then can choose, which meaning actually fits best in that specific search context.

Co-active intelligence systems are able to reveal associations that may not have been discovered yet, known as ‘emergent semantics’. For example, ‘big apple’ could also be associated with New York. In general, emergent semantics can also be used in another context like scientific cooperation or service discovery [2].

[1] Truran, M., Goulding, J., and Ashman, H. 2005. Co-active intelligence for image retrieval. In Proceedings of the 13th Annual ACM international Conference on Multimedia (Hilton, Singapore, November 06 – 11, 2005). MULTIMEDIA ’05. ACM, New York, NY, 547-550. DOI= http://doi.acm.org/10.1145/1101149.1101273

[2] K. Aberer, P. Cudre-Mauroux, A. M. Ouksel, T. Catarci, M.-S. Hacid, A. Il-
larramendi, V. Kashyap, M. Mecella, E. Mena, E. J. Neuhold, O. D. Troyer,
T. Risse, M. Scannapieco, F. Saltor, L. de Santis, S. Spaccapietra, S. Staab, and
R. Studer. 2004. Emergent Semantics Principles and Issues. In Procceedings of the 9th International Conference on Database Systems for Advanced Applications (DASFAA 2004).

First days at UniSA

Monday: 10:30 am. First meeting with Helen who’s my supervisor and responsible for the Security Laboratory at the University of South Australia (UniSA). Got some formal stuff done. Afterwards, Helen introduced me to some other students, working with me in the same lab. Then, a basic introduction to current projects followed. Rest of the day I spent with reading papers to get into the projects and surrounding topics. Also got my Health and Safety instructions. UniSA is very serious about that. Lunch at Subway, the sandwich bar. Left office at about 08:00 pm. Bought some stuff at Woolworths (open til 09:00 pm). Meat with mushrooms, tomatos, rice and salad for dinner.

Tuesday: 10:00 am. At the staff room. Instant coffee. Made with filtered water. Not as bad as it sounds. Rest of the day: paper reading. Trying to summarize a bit what I read. Lunch at Subway. Left office at about 06:30 pm. Pasta with fresh olives for dinner. 09:00 pm: Griffins pub in Adelaide city, going out with Gavin (one of Helens PhD students) and some exchange students. It’s 3 $ day! Spoke a bit German with John, an Austrian. There’re night buses on Saturdays only. Therefore: last bus at 11:00 pm.

Today: 10:00 am. Woke up feeling a bit ill. Aspirin. Sidenote: I should reintroduce to have breakfast. At the lab: Read papers again and did my online Health and Safety course, which took me about an hour. And still more to come. UniSA’s really serious about that. I even got instructions what to do, if someone planning a bomb attack calls me. Lunch at Darshana’s Indian and Sri Lankan restaurant. Good and cheaper than Subway. And the waitress is a beauty. In the evening, Jan-Felix, a third year undergraduate genius helping out in the lab, introduced me to a new project. We’re going to get together next Tuesday for details. Got home at 08:30 pm. Pasta with salad for dinner.

Time’s running. The first week is almost over. Two days left. Looking forward to the weekend. At the house nothing’s going on. Housemates are all really quiet. Jamies’s girlfriend is going to visit him on weekend. I’m going to be the kitty manager for September, responsible for trashbins, cleaning stuff,…

Got mobile!

Although it’s Sunday, most stores are open. So I went to Kmart for the first time in my life and purchased a pre-paid SIM for 4 $, my number is

+61 40 181 76 55

Send me a message! At least, you don’t have to pay for incoming calls, as you have to in Canada. Beside that, the first minute costs about 1 $, then 80 c/min (about 0,6 €/0,5 €). Every time I reload with 30 $, I get 120 $ for standard calls (reloading with 100 $ would get me extra 900 $). I can use that credit to call in any network here. But: credit expires after 30 days.

Also bought: a sleeping bag (to keep me warm @ night), 32 rolls of toilet paper, three pair of socks, a towel, post its, college block and house shoes for 60 $ (36 €). Wanted to check my credit card balance afterwards, but when I try to get my SecureCode (which is necessary to check balance online), Paylife always tells me, there’s a temporary problem (which lasts for hours now).

Had that house meeting today (instead of next Friday). Landlord communicated some things regarding kitchen cleaning: everything should be cleaned up right after use, “use-it-clean-it”, etc. We’re all fine with that.

Tomorrow’s my first day at University. Gonna meet with my supervisor Helen @ 10:30 @ “her” building, D3-13. She’ll show me around and stuff. This is the campus map. It’s compareable to the Hagenberg Campus. They also got a lake (like Hagenberg does under the Ellipse). But everything is way bigger. Took me 20 minutes to run around that lake today. Next to the lake there’re living houses everywhere. And across the street opposite to the lake there’s the campus.

Looking forward to meet up with Helen tomorrow and get some idea of my upcoming projects.

Catch ya later.