<chapter id="definitions">
<chapterinfo>
<authorgroup>
<author>
<firstname>Anne-Marie</firstname>
<surname>Mahfouf</surname>
<affiliation>
<address><email>annma@kde.org</email></address>
</affiliation>
</author>
<author>
<firstname>Raphael</firstname>
<surname>Langerhorst</surname>
<affiliation>
<address><email>raphael.langerhorst@kdemail.net</email></address>
</affiliation>
</author>
<!-- TRANS:ROLES_OF_TRANSLATORS -->
</authorgroup>
</chapterinfo> 
<title>Definitions</title>

<sect1 id="gantt">
<title>Gantt charts</title>
<para>A Gantt chart is a popular type of bar chart, that aims to show the timing
of tasks or activities as they occur over time. Although the Gantt chart did not
initially indicate the relationships between tasks this has become more
common in current usage as both timing and interdependencies between tasks can
be identified.
</para>
<para>
In project management, a Gantt chart can show when the project terminal elements
start and finish, summary elements (shown) or terminal element dependencies (not
shown). A terminal element is defined as the smallest task tracked as part of
the project effort. The tasks are displayed on a page as bars. The page is laid
out such that time increases as you move across the page. A task's start
time/date is indicated by the point on the page the bar starts, and it's
duration is indicated by the length of the bar.
</para>
<para>
Since the initial introduction of Gantt charts, they have become an industry
standard as a key project management tool for representing the phases, tasks and
activities that are scheduled as part of a project Work Breakdown Structure
(WBS) or timeline of tasks.
</para>
<para>
The initial format of the chart was developed by Henry L. Gantt (1861-1919) in
1910 (see <quote>Work, Wages and Profit</quote> by H. L. Gantt, published by The
Engineering Magazine, NY, 1910).
</para>
</sect1>

<sect1 id="wbs">
<title>Work Breakdown Structure (WBS)</title>
<para>
In project management, a work breakdown structure (WBS) is an exhaustive,
hierarchical (from general to specific) tree structure of deliverables and tasks
that need to be performed to complete a project.
</para>
<para>
The purpose of a WBS is to identify terminal elements (the actual items to be
done in a project). Therefore, WBS serves as the basis for much of project
planning.
</para>
<para>A useful rule of thumb is that any project can be broken down into
between 10 and 20 tasks.
</para>
<para>
Work breakdown structure is a very common project management tool. Many United
States government statements of work require work breakdown structures.
</para>
<para>See the <xref linkend="configure-wbs" /> section to learn how to
configure your WBS.
</para>
</sect1>

<sect1 id="float">
<title>Float</title>
<para>
Float in project management is the amount of time that a terminal element in a
project network can be delayed by, without causing a delay to:
<itemizedlist>
<listitem><para>subsequent terminal elements (free float)</para></listitem>
<listitem><para>project completion date (total float).</para></listitem>
</itemizedlist>
Float is sometimes also called slack.
</para>
</sect1>

<sect1 id="task">
<title>Task</title>
<para>
A task is a part of a project that needs to be accomplished within a defined
period of time. Tasks can be linked together to create Dependencies. 
</para>
<para>
Tasks take place over a period of time and generally consume resources.
</para>
<para>
A task is termed critical when it has zero or negative float.
</para>
<para>
In &kplato;, each task has a task ID, a name and a responsible person.
The timing, the cost and the assigned resources can also be set
in the <guilabel>Task Settings</guilabel>dialog.
</para>
<para>A subtask is any node in the WBS tree that has a task as its
parent.</para>

</sect1>

<sect1 id="resource">
<title>Resource</title>
<para>
A resource is an item required to complete a task. Resources can be
people, equipment, facilities, funding or anything else needed to perform the
work of a project. Resources can have a limited time availability (&ie; an
employee that works 8 hours a day, 5 days a week).
</para>
<para>The availability is
defined by <link linkend="calendar">calendars</link>.
</para>
<para>
In &kplato; resources are either persons (work) or machines/devices (material).
</para>
</sect1>

<sect1 id="calendar">
<title>Calendars</title>
<para>
A calendar defines at what time a <link linkend="resource">resource</link>
is available.
</para>
<para>
Calendars can be either a regular working week or special working times
that can be individually defined for each day. This allows for very subtle
control over the availability of resources.
</para>
<para>
Every <link linkend="resource">resource</link> is usually connected to a
calendar.
</para>
<para>
In &kplato; you can even use hierarchical calendars.
</para>
</sect1>

<sect1 id="milestone">
<title>Milestone</title>
<para>
A milestone is a scheduled event signifying the completion of a major
deliverable or a set of related deliverables (usually marking the end of a
period). A milestone  is an activity with zero duration and no effort &ie; there
is no work associated with a milestone. It is a flag in the workplan to signify
some other work has completed. 
</para>
<para>
Usually a milestone is used as a project checkpoint to validate how the project
is progressing and revalidate work. Milestones are also used as high-level
snapshots for management to validate the progress of the project. In many cases
there is a decision to be made at a milestone.
</para>
</sect1>

<sect1 id="critical-path">
<title>Critical path</title>
<para>A path is a series of connected tasks. In project management, a
critical path is the sequence of project network terminal elements with the
longest overall duration, determining the shortest time to complete the project.
</para>
<para>
The duration of the critical path determines the duration of the entire project.
Any delay of a terminal element on the critical path directly impacts the
planned project completion date (i.e. there is no float on the critical path).
For example, if a task on the critical path is delayed by one day, then the
entire project will be delayed by one day (unless another task on the
critical path can be accelerated by one day).
</para>
<para>
A project can have several, parallel critical paths. An additional parallel path
through the network with the total duration just shorter than the critical path
is called a sub-critical path.
</para>
<para>
Originally, the critical path method considered only logical dependencies among
terminal elements. A related concept is the critical chain, which adds resource
dependencies.
</para>
<para>
The critical path method was invented by the DuPont corporation.
</para>
</sect1>

<sect1 id="scheduling">
<title>Scheduling</title>
<para>
Scheduling is the process of creating a project schedule based on the project
data like <link linkend="task">tasks</link>,
<link linkend="resource">resources</link> and
<link linkend="calendar">calendars</link>. The result can be viewed in a chart,
like a <link linkend="gantt">gantt chart</link>. &kplato; can also generate
reports for a project.
</para>
<para>
There are usually various scheduling modes, like optimistic, expected and
pessimistic scheduling. When creating a task the additional estimation
percentage
for optimistic and pessimistic scheduling can be set. These settings are then
used for the various scheduling modes.
</para>
<para>
When scheduling a project with &kplato;, you can choose between optimistic,
expected and pessimistic scheduling.
</para>
</sect1>

</chapter>
