In a 14 day exhibition, there will have a counter at which participants can register. For this exhibition, the organizers will employ 5 students to work at the counter, where for every day there will be three students working. According to labour law, every student can only work for a maximum of 9 days in a period of 14 days. Every student also has some restrictions and preferences on the day he / she would like to work. Some students have indicated that they could not work on certain days. Some students also indicated that they prefer to work on certain days rather than on any other days.

3.1 GOAL

 

The goal of this exercise is to develop a simple application with the following functionalities:

 

x     Decision Support System: a system with which the user could manually decide on which day each student should work.

 

 

 

3.2 DATA

 

x     We have 14 days on which we have to plan students. Every day has an ID, referring to the date of the day. The first day is the Monday next week.

 

x     We have 5 students to be planned. Every student has an ID, which is simply a number (1, 2,….5)

 

 

3.3 CONSTRAINTS

 

The planning solution has the following constraints:

 

x     Every day needs exactly 3 students.

 

x     Every student can only work for a maximum of 9 days in total.

 

x     Every student has certain restrictions and preferences. Some students are not allowed to work on certain days at all, and some students prefer to work on certain days rather than any other days in a week.

 

To model the employees’ restrictions and preferences, we will use a simple table consisting of the following four columns:

 

-    ID                 : indicating the ID of the student.

 

-    WeekDay      : indicating the day within a week. The WeekDay will have a value of

[1..7],  where 1 = Monday, 2 = Tuesday, …7 = Sunday.

 

-      Allowed        : indicating whether an assignment on a certain day is allowed. This column will have two possible values:  TRUE or FALSE.

 

-    Penalty         : indicating the degree of preference of a certain assignment. The less preferred the assignment is, the higher the penalty would be. An assignment on a day which is not allowed will have the highest penalty.

 

 

 

 

 

Below is an example of the table.

 

  ID	  WeekDay	  Allowed	  Penalty
  1	  1	  FALSE	  10
  1	  6	  TRUE	  5
  1	  *	  TRUE	  0

 

 

The above table shows:

 

x      Student 1 is not allowed to work on Monday (Weekday = 1). If he is planned on

Monday, there will be a constraint violation, and there will also be a penalty of 10.

 

x      Student 1 does not like to work on Saturday (Weekday = 6). If he is planned on

Saturday, there will be a penalty of 5.

 

x      Student 1 could be planned on any other days without penalty.

 

The total score / penalty of all assignments (and also the number of constraint violations) together determine how good the planning solution is.