2.2 Abstract Model of Mobile Processes
Based on the definition of mobile processes given in Section 1.1.2, this section offers deeper insight into the properties of mobile processes as considered in this work. To develop a business independent domain specific model of mo-bility as well as of the execution of mobile work, it is necessary to understand the differences and commonalities of mobile business processes. Figure 2.6 gives an overview of the typical administrative parts of any mobile process:
actAbstract Mobile Process
Preparation Assignment Performance Completion
optional
Figure 2.6: Abstract mobile process
Preparation of a mobile task includes gathering and bundling necessary information and material. It is carried out at the organization’s head-quarter or at the depot of the region. An example for preparing the inspection of a municipality’s power network is to print both the ac-cording network’s map and the listing of all points of special interest as, e.g., power substations.
Assignment of a mobile task to a worker appoints the worker to execute this task. For the assignment it is necessary to determine the appro-priate qualification of workers capable to execute the task and to de-termine the scheduling algorithm. To assign a task to a worker, the task’s required qualifications must be in the set of the worker’s skills.
Due to the fact, that traveling contributes considerably to the costs of mobile processes, it is not possible to provide the worker with work items during the working day, but it is necessary to manage work lists which contain a worker’s activities for a given period of time (e.g., one day) in chronological order. The assignment of the task to the worker is performed manually or automatically and is carried out at the organization’s headquarter or at the depot of the region. Date may be transferred to the worker at the headquarter (face-to-face) or via wireless data communication.
Performance of a mobile task includes that the worker travels to the site of work, the actual work, and that the worker gathers work-related information on-site. It is mainly carried out at the task’s location.
Completion of a mobile task includes analyzing the work results, account-ing, updating technical data, and planning further measures, if
neces-18 CHAPTER 2. DOMAIN MODEL OF MOBILITY sary. It is typically executed at the headquarter or at the depot of a region of the respective organization.
As marked in Figure 2.6, the steps considered in this work are the assignment of mobile tasks to workers and the performance of the mobile tasks. These are the process steps that are influenced by the properties of mobility.
2.2.1 Assignment of Mobile Work
The primary goal of assigning mobile work is to minimize the total process costs of an organization. An in-depth discussion of these costs and their relations is presented in Section 2.5. The resulting secondary goals of assign-ing work are to execute the cases with the highest priority first, to reduce travel effort, and to avoid workers having idle times. The general assignment activities are depicted in Figure 2.7.
actTask Assignment
Sort Cases
Select Case
Insert Tasks into Schedules
[incomplete schedules]
[all schedules complete]
Figure 2.7: Assignment of a mobile task
The assignment can either be performed manually or automatically. If it is performed manually, a foreman or dispatcher allocates the work items to the workers based on the experience as well as on the spatial distribution of the workers. If, alternatively, the assignment is performed automatically by a workforce management system, the system allocates the work items based on preset priorities, expected travel times, and interdependencies of the cases and tasks. Nonetheless, for the general course of the assignment, it is not necessary to differentiate between manual and automatic assignment.
At the beginning of a planning period the pending cases are sorted by pri-ority. The resulting list of the cases is then processed top-down. Every case is split into its tasks, and the tasks are inserted into the schedules of suited workers. Whether a worker is suited for executing a certain task depends on his skills, on his geographic location, and on the tasks already present in his schedule. Algorithms for solving the respective workforce scheduling problem will be presented and discussed in Chapter 4. After a case is in-serted into the workers’ schedules either all schedules are complete or not.
The assignment of mobile work is finished as soon as all schedules are com-plete, otherwise the next case is selected and inserted into the schedules still
2.2. ABSTRACT MODEL OF MOBILE PROCESSES 19 incomplete. A schedule is considered complete if it contains tasks for a whole planning period—e.g., expected working and travel times sum up to eight or nine hours of a working day.
2.2.2 Performance of Mobile Work
Independently from the business objectives, the performance of a mobile business process follows a general scheme. For each task of a process the steps depicted in Figure 2.8 have to be executed.
actTask Execution
Travelto task’s location
Waitfor end of preceding tasks
Execute the task
Finalizethe task
Figure 2.8: Execution of a mobile task
Traveling is the transfer of the worker responsible for executing a task to the location of that task. It starts at the depot of this worker (for the first task of the day) or at the location of another task that has been accomplished by the worker before. In this work, traveling to a task’s location is considered to belong to that task. In contrast traveling from the task’s location does not belong to that task but to the next task in the worker’s schedule.
Waiting may be necessary after the location of the task has been reached by the worker and either (i) the time window of the task has not been reached yet or (ii) a preceding task of the case has not been finished yet.
As an example for the latter consider the process depicted in Figure 2.3. The task “Work @L3” must not start until the tasks “Off @L1” and
“Off @L2” are finished.
Execution of a task refers to accomplishing the business objective of this part of the case. In this work, the execution of tasks is considered from an administrative point of view only. It is thus considered as an economically weighted period of time which blocks a worker at a certain location with certain costs. The actual business value added does not need to be considered for the purpose of this work.
Finalization of a task involves gathering data that describes the work re-sults. This includes business data as, e.g., the nature and amount of material consumed as well as administrative data as, e.g., consumed time.
20 CHAPTER 2. DOMAIN MODEL OF MOBILITY