Ubuntu Manpage: mailfoot - a full-online-ordered-training simulator for use with dbacl.

NAME

       mailfoot - a full-online-ordered-training simulator for use with dbacl.

SYNOPSIS


       mailfoot command [ command_arguments ]

DESCRIPTION

mailfoot automates the task of testing email filtering and classification programs such as dbacl(1).
Given a set of categorized documents, mailfoot initiates test runs to estimate the classification errors
and thereby permit fine tuning of the parameters of the classifier.

Full Online Ordered Training is a learning method for email classifiers where each incoming email is
learned as soon as it arrives, thereby always keeping category descriptions up to date for the next
classification. This directly models the way that some email classifiers are used in practice.

FOOT's error rates depend directly on the order in which emails are seen. A small change in ordering, as
might happen due to networking delays, can have an impact on the number of misclassifications.
Consequently, mailfoot does not give meaningful results, unless the sample emails are chosen carefully.
However, as this method is commonly used by spam filters, it is still worth computing to foster
comparisons. Other methods (see mailcross(1),mailtoe(1)) attempt to capture the behaviour of
classification errors in other ways.

To improve and stabilize the error rate calculation, mailfoot performs the FOOT simulations several times
on slightly reordered email streams, and averages the results. The reorderings occur by multiplexing the
emails from each category mailbox in random order. Thus if there are three categories, the first email
classified is chosen randomly from the front of the sample email streams of each type. The second email
is also chosen randomly among the three types, from the front of the
streams after the first email was removed. Simulation stops when all sample streams are exhausted.

mailfoot uses the environment variable MAILFOOT_FILTER when executing, which permits the simulation of
arbitrary filters, provided these satisfy the compatibility conditions stated in the ENVIRONMENT section
below.

For convenience, mailfoot implements a testsuite framework with predefined wrappers for several open
source classifiers. This permits the direct comparison of dbacl(1) with competing classifiers on the same
set of email samples. See the USAGE section below.

During preparation, mailfoot builds a subdirectory named mailfoot.d in the current working directory.
All needed calculations are performed inside this subdirectory.

EXIT STATUS

       mailfoot returns 0 on success, 1 if a problem occurred.

COMMANDS

prepare size
Prepares a subdirectory named mailfoot.d in the current working directory, and populates it with
empty subdirectories for exactly size subsets.

add category [ FILE ]...
Takes a set of emails from either FILE if specified, or STDIN, and associates them with category.
The ordering of emails within FILE is preserved, and subsequent FILEs are appended to the first in
each category. This command can be repeated several times, but should be executed at least once.

clean Deletes the directory mailfoot.d and all its contents.

run Multiplexes randomly from the email streams added earlier, and relearns categories only when a
misclassification occurs. The simulation is repeated size times.

summarize
Prints average error rates for the simulations.

plot [ ps | logscale ]...
Plots the number of errors over simulation time. The "ps" option, if present, writes the plot to a
postscript file in the directory mailfoot/plots, instead of being shown on-screen. The "logscale"
option, if present, causes the plot to be on the log scale for both ordinates.

review truecat predcat
Scans the last run statistics and extracts all the messages which belong to category truecat but
have been classified into category predcat. The extracted messages are copied to the directory
mailfoot.d/review for perusal.

testsuite list
Shows a list of available filters/wrapper scripts which can be selected.

testsuite select [ FILTER ]...
Prepares the filter(s) named FILTER to be used for simulation. The filter name is the name of a
wrapper script located in the directory /usr/share/dbacl/testsuite. Each filter has a rigid
interface documented below, and the act of selecting it copies it to the mailfoot.d/filters
directory. Only filters located there are used in the simulations.

testsuite deselect [ FILTER ]...
Removes the named filter(s) from the directory mailfoot.d/filters so that they are not used in the
simulation.

testsuite run [ plots ]
Invokes every selected filter on the datasets added previously, and calculates misclassification
rates. If the "plots" option is present, each filter simulation is plotted as a postscript file in
the directory mailfoot.d/plots.

testsuite status
Describes the scheduled simulations.

testsuite summarize
Shows the cross validation results for all filters. Only makes sense after the run command.

USAGE

The normal usage pattern is the following: first, you should separate your email collection into several
categories (manually or otherwise). Each category should be associated with one or more folders, but each
folder should not contain more than one category. Next, you should decide how many runs to use, say 10.
The more runs you use, the better the predicted error rates. However, more runs take more time. Now you
can type

% mailfoot prepare 10

Next, for every category, you must add every folder associated with this category. Suppose you have three
categories named spam, work, and play, which are associated with the mbox files spam.mbox, work.mbox, and
play.mbox respectively. You would type

% mailfoot add spam spam.mbox
% mailfoot add work work.mbox
% mailfoot add play play.mbox

You should aim for a similar number of emails in each category, as the random multiplexing will be
unbalanced otherwise. The ordering of the email messages in each *.mbox file is important, and is
preserved during each simulation. If you repeatedly add to the same category, the later mailboxes will be
appended to the first, preserving the implied ordering.

You can now perform as many FOOT simulations as desired. The multiplexed emails are classified and
learned one at a time, by executing the command given in the environment variable MAILFOOT_FILTER. If not
set, a default value is used.

% mailfoot run
% mailfoot summarize

The testsuite commands are designed to simplify the above steps and allow comparison of a wide range of
email classifiers, including but not limited to dbacl. Classifiers are supported through wrapper
scripts, which are located in the /usr/share/dbacl/testsuite directory.

The first stage when using the testsuite is deciding which classifiers to compare. You can view a list
of available wrappers by typing:

% mailfoot testsuite list

Note that the wrapper scripts are NOT the actual email classifiers, which must be installed separately by
your system administrator or otherwise. Once this is done, you can select one or more wrappers for the
simulation by typing, for example:

% mailfoot testsuite select dbaclA ifile

If some of the selected classifiers cannot be found on the system, they are not selected. Note also that
some wrappers can have hard-coded category names, e.g. if the classifier only supports binary
classification. Heed the warning messages.

It remains only to run the simulation. Beware, this can take a long time (several hours depending on the
classifier).

% mailfoot testsuite run
% mailfoot testsuite summarize

Once you are all done, you can delete the working files, log files etc. by typing

% mailfoot clean

SCRIPT INTERFACE

mailfoot testsuite takes care of learning and classifying your prepared email corpora for each selected
classifier. Since classifiers have widely varying interfaces, this is only possible by wrapping those
interfaces individually into a standard form which can be used by mailfoot testsuite.

Each wrapper script is a command line tool which accepts a single command followed by zero or more
optional arguments, in the standard form:

wrapper command [argument]...

Each wrapper script also makes use of STDIN and STDOUT in a well defined way. If no behaviour is
described, then no output or input should be used. The possible commands are described below:

filter In this case, a single email is expected on STDIN, and a list of category filenames is expected in
$2, $3, etc. The script writes the category name corresponding to the input email on STDOUT. No
trailing newline is required or expected.

learn In this case, a standard mbox stream is expected on STDIN, while a suitable category file name is
expected in $2. No output is written to STDOUT.

clean In this case, a directory is expected in $2, which is examined for old database information. If
any old databases are found, they are purged or reset. No output is written to STDOUT.

describe
IN this case, a single line of text is written to STDOUT, describing the filter's functionality.
The line should be kept short to prevent line wrapping on a terminal.

bootstrap
In this case, a directory is expected in $2. The wrapper script first checks for the existence of
its associated classifier, and other prerequisites. If the check is successful, then the wrapper
is cloned into the supplied directory. A courtesy notification should be given on STDOUT to
express success or failure. It is also permissible to give longer descriptions caveats.

toe Used by mailtoe(1).

foot In this case, a list of categories is expected in $3, $4, etc. Every possible category must be
listed. Preceding this list, the true category is given in $2.

ENVIRONMENT

       Right  after loading, mailfoot reads the hidden file .mailfootrc in the $HOME directory, if it exists, so
       this would be a good place to define custom values for environment variables.

       MAILFOOT_FILTER
              This variable contains a shell command to be executed repeatedly during the  running  stage.   The
              command  should  accept  an  email  message  on STDIN and output a resulting category name. On the
              command line, it should also accept first the true category name, then  a  list  of  all  possible
              category  file  names.  If the output category does not match the true category, then the relevant
              categories are assumed to have been silently updated/relearned.  If MAILFOOT_FILTER is  undefined,
              mailfoot uses a default value.

       TEMPDIR
              This  directory  is  exported  for  the  benefit  of wrapper scripts. Scripts which need to create
              temporary files should place them a the location given in TEMPDIR.

NOTES

       The subdirectory mailfoot.d can grow quite large. It contains a full copy of  the  training  corpora,  as
       well as learning files for size times all the added categories, and various log files.

       FOOT  simulations  for dbacl(1) are very, very slow (order n squared) and will take all night to perform.
       This is not easy to improve.

WARNING

       Because the ordering of emails within the added mailboxes matters, the estimated error rates are not well
       defined or even meaningful in an objective sense.  However, if the  sample  emails  represent  an  actual
       snapshot  of  a  user's incoming email, then the error rates are somewhat meaningful. The simulations can
       then be interpreted as alternate realities where a given classifier would have intercepted  the  incoming
       mail.

SOURCE

       The source code for the latest version of this program is available at the following locations:

       http://www.lbreyer.com/gpl.html
       http://dbacl.sourceforge.net

AUTHOR

       Laird A. Breyer <laird@lbreyer.com>