[{TableOfContents title='Terminology - Contents' numbered='true'}]


!!! Solutions

We define the competence of the knowledge base by enumerating all possible solutions, i.e., faults, for the printer problem. 
The derivable solutions are as follows:

# Connection problems
## Broken cable
## Cable not connected
## No Wifi connection
## No power supply
# Printing quality problems
## Empty toner
## Dirty toner

We see, that we have structured the solutions into meaningful groups, i.e. ''connection problems'' and ''printing quality problems''. 
More groups can be added easily.
The structuring of solutions is especially useful when the knowledge base and the number of solutions, respectively, increases.

The d3web markup of the solution hierarchy is as follows:

{{{
%%Solution 
Connection problems
- Broken cable
- Cable not connected
- No Wifi connection
- No power supply
Printing quality problems
- Empty toner
- Dirty toner
No solution found  
%
}}}

Please note, that we added the solution ''No solution found'' for the case, that the system cannot derive an appropriate solution. 
When inserting the markup into the wiki article, the following section is shown.

%%Solution 
Connection problems
- Broken cable
- Cable not connected
- No Wifi connection
- No power supply
Printing quality problems
- Empty toner
- Dirty toner
No solution found   
%

!!! Questions

To derive the solutions we need to pose appropriate questions to the user. 
Since, we expect many questions to be included in the knowledge base, we group the questions into meaningful questionnaires.

First, we define an initial questionnaire that tries to identify the problem area of the user and use the following markup:
{{{
%%Question 
Problem specification #1
- Please specify your problem [oc]
-- Printer does not print
-- Printing with bad quality
-- No else
%
}}}

The annotation ''#1'' specifies, that the questionnaire ''Problem specification'' is posed as the initial questionnaire in a dialog session with the user.
When inserting the markup into the article, the questions are created.

%%Question 
Problem specification #1
- Please specify your problem [oc]
-- Printer does not print
-- Printing with bad quality
-- No else
%

The annotation ''~[oc]'' specifies a corresponding one-choice question. 
The possible values/answers of this question are printed in separate lines below the question.
Each value/answer should be indented by an increased dash.
We see, that the three answers ''Printer does not print'', ''Printing with bad quality'', and ''No else'' has been defined for the one-choice question ''Please specify your problem''.

Each problem area corresponds to a group of solutions.
That way, we define a questionnaire for each problem area in order to differentiate the solutions within the problem area.

!! Problem Area: Connection Problems 

The questions of the problem area ''connection problems'' are as follows:

%%Question 
Connection Questions 
- Please check the power supply of the printer [oc]
-- Printer is connected and power is on
-- Printer is not connected or power is off
- How is the printer connected to your computer [oc]
-- Connected by cable
-- Connected by Wifi
Printer with cable connection
- Is the cable plugged into the printer and the computer [yn]
-- Yes
-- No
- Please exchange the cable and try to print again [oc]
-- Stil not printing
-- Now it works
%

We see, that a number of one-choice questions (~[oc]) are defined. 
Additionally, a yes/no question is defined (~[yn]), which is similar to one-choice questions, but has the predefined answers ''yes'' and ''no''.

!! Problem Area: Quality Problems

The questions of the problem area ''quality problems'' are as follows:

%%Question 
Quality Questions
- Dirty housing [yn]
- Toner capacity  [num] {pages} (0 10000000)
- Paper count  [num] {pages} (0 10000000)
-- Current capacity ratio [num] <abstract>
-- Toner usage evaluation [oc] <abstract>
--- normal
--- low 
%

In addition to yes/no questions and one-choice questions we defined some numerical questions (~[num]), that allow the input of numerical values. The annotation ''(0 10000000)'' defines the value range of the particular question, i.e., numbers from 0 to 10000000 can be entered, whereas ''{pages}'' defines the unit as an arbitrary string, i.e., the number of ''pages'' is queried to the user.
The annotation ''<abstract>'' specifies a abstraction question.
For such a question the values are not entered externally, e.g., by a user in a dialog, but the values are computed internally by the knowledge base.

For the internal computation of the abstraction questions we define the following rules, by the {{Rule}} markup.
In the following, we define a rule computing the ratio between the expected toner life (''Toner capacity'') and the current use (''Paper count''). 
Two further rules derive a ''normal'' or a ''low'' toner usage by using the derived value of the abstraction question ''Current capacity ratio'':

{{{
%%Rule
IF   Toner capacity = KNOWN AND Paper count > 0
THEN Current capacity ratio = (Toner capacity / Paper count)

IF   Current capacity ratio >= 1.1
THEN Toner usage evaluation = normal

IF   Current capacity ratio < 1.1
THEN Toner usage evaluation = low
%
}}}

When inserted into the wiki article, the rules markup looks as follows:

%%Rule
IF   Toner capacity = KNOWN AND Paper count > 0
THEN Current capacity ratio = (Toner capacity / Paper count)

IF   Current capacity ratio >= 1.1
THEN Toner usage evaluation = normal

IF   Current capacity ratio < 1.1
THEN Toner usage evaluation = low
%

!! Human-friendly Prompts of Questions/Solutions

It is reasonable to define short names for questions and solutions because they are often used in the markups.
When used in the dialog, however, longer verbalizations may be useful.
You can define a longer prompt for questions/solutions by using the {{Property}} markup.
Moreover, the prompts can be internationalized.

%%Property 
  Dirty housing.prompt = When opening the housing of the printer: Is there some dirt at the toner and the surrounding?
  Toner capacity.prompt = Number of pages usually printed with one toner
  Paper count.prompt = Number of pages printed with the current toner
  Paper count.prompt.de = Anzahl der mit den aktuellen Toner gedruckten Seiten
%

%%Package Printer_Demo