Getting this error constantly: IOUnserialize has detected a string that is not valid UTF-8
It looks like your Mavericks installation had a hick up.

Reinstall it.

To find out the source one has to open the pref files of all named processes and look for the UTF-8, "~?�"

You wont be able to fix it there but maybe see it.

You can try the search with Terminal fgrep -iR "~?�" /Library/Preferences

There is also a way to investigate the 


  configd


You can debug configd by running another copy. You type in the terminal:

sudo /usr/libexec/configd -dv


It will ask for you password. This should give you debugging info about each bundle as it loads and dump any messages that normally go into the syslog to the terminal window. 

You can load each bundle mentioned in your console log one at a time too e.g:

sudo /usr/libexec/configd -dv -t /System/Library/SystemConfiguration/Logger.bundle


Use ctrl-c to quit the process.

The number is the process id listed in the leftmost column in the Activity Monitor next to the process you want to close.

Looking at your console log, it looks like the common theme is Network. It might have to do with your airport app, but not sure since insufficient information given.

Does it comes up in Safe mode?