Allocation

Allocation is a state in which a participant in charge of some work item is determined.

Overview of Allocation
In workflow research, Allocation is one of the states of work items and means a state in which a participant in charge of some work item is determined.Upon allocation, although a participant in charge of a work item is determined, the work item is not yet started. In addition, there are two possible cases before reaching "Allocation state." While candidates for a work item are chosen (Offer) in advance in some cases, in the other cases allocation is done without choosing candidates.

A participant allocated to a work item is in charge of the work item, and he/she has to be responsible for the work item.

Some examples of "Allocation state" are: a state in which a name of a participant in charge of some work item is announced, a state in which a supervisor assigns some task to some participant, and so on.

Besides "Allocation state," processing states include "Create state," "Offer state," "Start state," and "Complete state."

In addition, manpower and physical resources required to execute a work item are called resources even though we used a term "a participant in charge of a work item" above.

Resource Model
Resources mean manpower and physical resources that are necessary to execute work items and are classified as either human resources or non-human resources, such as factories and equipments. Resources are basically members of an organization and belong to one or more departments in the organization. In addition, each resource is assigned a rank in the organization and has a capability to allocate other resources before starting its own task.

Non-human resources are categorized as either durable resources or consumable resources. Durable resources can undertake work items without being affected by the number of work items that they are in charge of. On the other hand, consumable resources are consumed, either partly or entirely, to complete work items.

Each resource has a schedule and history. A schedule is a list of work items that the resource is going to undertake in the future while a history is a list of work items that the resource has completed.

State Transition of Work Items
It is also called a life cycle of work items. Basically, a state of work items changes as follows.
 * 1) A work item is ready for execution. (Create)
 * 2) Candidates for the work item are chosen. (Offer)
 * 3) A participant to execute the work item is chosen. (Allocation)
 * 4) A work item is started or in progress (Start)
 * 5) A work item is completed (Complete)

Sometimes the state changes directly from Create to Allocation, skipping Offer. In addition, there is "Fail" state in case a resource can not complete the work item and does not work on it again. Note that only one resource actually undertakes a work item while multiple resources can be offered. Thus, allocation is done only to one resource.

By way of exception to this state transition process, there are Detour Patterns, which categorize special processes that skip a work item, leave a work item to another resource, or suspend and resume a work item.

State Transition without "Offer State"
In some cases, a work item becomes "Allocation state" without going through "Offer state." Such cases happen when a certain resource is allocated without being asked whether it intends to undertake the work item or not or without making offers to other resources. In these cases, the resource often does not know at all or almost nothing about what the work item that it undertook is like. As soon as the resource completes one work item, a new work item is allocated. And then the resource is required to start working on the new work item without knowing what it is required to do next. The purpose of such transition is to maximize the processing capability by making resources always busy.

Creation Patterns
Creation Patterns are the pattern categorizations of the ways in which states of created work items are changed to Offer and Allocation. There are capability-based approach, achievement-based approach, and so forth. There are 11 patterns shown below.
 * DA (Direct Allocation)
 * RBA (Role-Based Allocation)
 * Deferred Allocation
 * Authorisation
 * Separation of Duties
 * Case Handling
 * Retain Familiar
 * CBA (Capability-based Allocation)
 * HBA (History-based Allocation)
 * Organisational Allocation
 * Automatic Execution

Related Articles

 * Offer
 * Workflow Engine
 * Workflow Pattern
 * Participant
 * Swimlane