Kai Witte's Blog

Chess puzzle #9 (easy)

June 30th, 2008

Black to move and win significant material.

Posted in Chess | No Comments »

Chess puzzle #12 (easy)

June 30th, 2008

vjoe (white) made a mistake here. How could I (black) have won material?

Solution: show 18. … Na4 19. Qc1 Nxd4

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Chess puzzle #10 (easy)

June 30th, 2008

I (black) made a mistake in a game against vjoe (white) here.

White to move and win material.

Solution: show

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Chess puzzle #7 (easy)

June 30th, 2008

I lost this game, because I missed my last chance at this position, where Black just made a horrible blunder.

Find a good sequence of moves for me (white).

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I use AWStats to get statistical usage information about my websites. The problem is that for less important websites like my private one I often test and develop directly on the production system. That creates many garbage entries in the HTTP log.

AWStats has the option SkipHosts for the configuration file, but my IP changes all the time.

So what I did was this:

Modify awstats.pl

...
if ($param =~ /^SkipHosts/) {
    @SkipHosts=();
        #foreach my $elem (split(/\s+/,$value)) {
        #       if ($elem =~ /^REGEX\[(.*)\]$/i) { $elem=$1; }
        #       else { $elem='^'.quotemeta($elem).'$'; }
        #       if ($elem) { push @SkipHosts, qr/$elem/i; }
        #}
        ####
        my $ips="/home/whoever/ips.txt";
        open(DAT, $ips) || die("can't open ip list");
        my @lines=<DAT>;
        close(DAT);
        foreach my $line (@lines)
        {
                chop($line);
                my $esc='^'.quotemeta($line).'$';
                push @SkipHosts, qr/$esc/i;
        }
        ####
        next;
        }
...

(You may want to keep the old code which I commented out and concatenate it with your values for @SkipHosts.)

Log my IPs

How that can be done depends on the situation. In my case I can safely assume that I have logged in to the web server over ssh with most IPs that I would use, so I added this to the .bash_profile:

echo $SSH_CLIENT | egrep -i -o '([[:digit:]]+\.){3}[[:digit:]]+' >> ips.txt

Hope it helps someone.

Tags: AWStats, my host, my IP, SkipHosts
Posted in Computers | 1 Comment »

Effective Enthuware

June 29th, 2008

Based on my certifications I have a some experience with exam simulators and mock questions from other sources. The years I served as a student assistant at the Leibnitz Institute for Science Education as well as my personal interest in this topic supplied me with a background in learning techniques. This post describes how to apply the Leitner System to the Enthuware Test Studio.

The Enthuware Test Studio is a software that can mock a test environment and provide various additional exam preparation tools. “Question Banks” can be purchased for it and loaded. I bought the Question Bank for the Sun Certified Business Component Developer for the Java Platform, Enterprise Edition 5 (CX-310-091), because I have the old version of the certificate and want to upgrade.

The Leitner System

The Leitner System is a method of grouping questions based on how often and when they need to be repeated. Enthuware Test Studio does not directly support it, but unlike Whizlabs it provides an indirect way using the study notes.
Enthuware Test Studio Missed Questions

When an answer is wrong, the question will end up in the section “Missed Questions” automatically
That section shows the questions in a table which can and should be sorted by the custom note (”My Note”)
After a missed question has been tried again, enter the corresponding box number of the Leitner System as a note using the “Edit Note” button on the bottom of the question window. (Increase number for correct answer, back to box one for wrong answer.)
Re-order by “My Note” when the boxes changed. Repeat questions in a frequency based on their box number (low numbers more often).

Shortcomings:

Only questions that have been missed the first time will end up in the “Missed Questions” section, although according to the Leitner System they would still have to be repeated a couple of times in decreasing intervals. But especially when time is short this can also be an advantage. If any questions can be skipped, then those which had been answered correctly at the first attempt.
It is possible to memorise the position of the answers in a multiple-choice or single-choice question, because Enthuware Test Studio does not support shuffling the order of the answers.

I found those shortcomings to be acceptable.

Overall learning approach

Learn the basics about the test subject from a general book or tutorial and practice. (The Sun EE Tutorial is great for SCBCD, SCWCD and SCDJWS.)
Study a single exam topic from the certification, for example in Mikalai Zaikin’s study guides
Make a custom test in Enthuware Test Studio with a subset of the available questions for this exam topic (not too many) and take it.
While repeating this routine for the other questions of the same exam topic and later for other exam topics, integrate repeating of missed questions based on the system above into your daily routine.

Tags: Certification, Java, Learning, Simulator
Posted in Computers | 2 Comments »