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Siebel Field Service Guide > Setting Up and Using Scheduling >
Creating Constraint Sets for Scheduling
This task is a step in Process of Setting Up Scheduling. Service businesses have a number of union, legal, or business constraints under which they must operate. Examples of Constraints lists a few examples of constraints. These constraints can be described as hard or soft, depending on whether or not they can be violated to meet scheduling requirements. The ABS uses only hard constraints while the Optimizer uses both hard and soft constraints.
- Hard constraints. The ABS and Optimizer cannot violate hard constraints. Activities that do not fit these constraints are not scheduled. As a result, the engines are faster in finding solutions, but fewer solutions are obtained. The solutions result in higher costs for service.
- Soft constraints. The Optimizer can weight the cost of using or violating a soft constraint when calculating solutions for a schedule. Soft constraints result in longer optimization times (lower performance of the Optimizer), more solutions, and lower costs for service. Violating soft constraints may result in a more costly schedule.
- Schedules that violate hard constraints are discarded even though they may be better than other solutions. The Optimizer may use solutions that violate soft constraints, but it assigns a penalty to these violations that could make one solution less favorable than another solution. The cost function calculated for each solution includes the penalties for violating soft constraints. For more information, see Defining Cost Functions for the Optimizer.
To create constraint sets, perform the following tasks:
Examples of Constraints
The following constraints limit work hours:
- Union contracts stipulate that no worker does more than ten hours of overtime in a week.
- Laws regulating worker safety restrict employees from working more than twelve hours a day.
- To keep costs down, management specifies that no service manager should authorize more than forty hours of overtime per week for all of their employees.
- An engineer cannot work more than 45 hours per week.
- An engineer cannot engage in an activity type (for example, working with hazardous materials) more than four hours per day.
- Total workload must be less than 95 percent.
- Total workload must be greater than 60 percent.
- An engineer cannot travel more than four hours a day, for safety reasons.
The following constraint limits timing of an activity: All waste disposal activities must start before 8 P.M. Predefined Constraints
Constraints fall into the categories shown in Table 27.
Table 27. Constraints for the ABS and Optimizer
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Appointment Booking
Activity Time |
Limits the time of day an activity of a specified type or priority can start or end. |
Appointment Booking FSE Limit |
Limits the number of activities of any type or of a specified type, or time spent on activities by any employee or a specific employee. Or, limits the number of activities or time spent on activities that have a specified service role (for example, Installation or Preventive Maintenance). |
Appointment Booking Schedule Activity Type |
Limits the number of activities of any type, or time spent on activities of a specified type for a whole schedule. |
Optimizer Activity Time Hard |
Limits when an activity of a specified type or priority must begin or end. This is a hard constraint. |
Optimizer Activity Time Soft |
Limits when an activity of a specified type or priority may begin or end. Also, specifies the penalty for violating this soft constraint. |
Optimizer FSE Limit Hard |
Limits the following values for any employee or a specific employee during a specified period:
- % workload
- Number of activities of any type or of a specified type
- Total hours of travel time
- Total work hours
This is a hard constraint. |
Optimizer FSE Limit Soft |
Limits the following values for any employee, a specific employee, or a specified service role (for example, Installation or Preventive Maintenance) during a specified period:
- % workload
- Number of activities of any type or of a specified type
- Total hours of overtime
- Total hours of travel time
- Total work hours
Also, specifies the penalty for violating this soft constraint. |
Optimizer Fairness |
Ensures the equal distribution of the following values for workload, specified as a percentage, for all employees or for a specified service role (for example, Installation or Preventive Maintenance):
- Number of activities of any type or of a specified type
- Total hours of overtime
- Total hours of travel time
- Total work hours
Also, specifies the penalty for violating this soft constraint. NOTE: Optimizer Fairness is called a leeway constraint because it is based on a percentage rather than an absolute value. As this is an approximate number, it allows the Optimizer to achieve acceptable schedule assignments within acceptable times.
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Optimizer Schedule Activity Type Hard |
Limits the following values for a whole schedule in a specified period:
- Hours of work time for activities of a certain type
- Number of activities of a certain type
- Percentage count of activities of a certain type1
- Percentage hours for activities of a certain type1
This is a hard constraint. |
Optimizer Schedule Activity Type Soft |
Limits the following values for a whole schedule:
- Hours of work time for activities of a certain type
- Number of activities of a certain type
- Percentage count of activities of a certain type
- Percentage hours for activities of a certain type
Also, specifies the penalty for violating this soft constraint. |
Optimizer Schedule Overtime Soft |
Limits the hours of overtime in a specified period for a whole schedule. Also, specifies the penalty for violating this soft constraint. |
Optimizer Travel Time |
Limits the travel time between activities for all employees, specific employees, or a specified service role (for example, Installation or Preventive Maintenance). This can be a hard or soft constraint. |
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