The third goal of demand engineering reading notes

Definition: The goal is about the purpose, attribute or use intention of the system.

AND decomposition of target: The decomposition of parent target G to a group of child targets is AND decomposition, if and only if all child R targets of parent target G must be satisfied.

OR decomposition target: the decomposition of the parent target G into a group of sub-targets is OR decomposition, and the parent target G can only be satisfied if and only if any sub-target is satisfied.

1. "Need" dependency

Definition: If meeting G2 is the premise of meeting G 1, then the "demand" of G 1 depends on the target G2.

2. "Support" dependency

Definition: If the satisfaction of target G 1 has a positive impact on the satisfaction of target G2, then G 1 supports G2.

And/or decomposition also mean this "supporting" dependency.

3. "Hinder" dependence

Definition: If the satisfaction of target G 1 hinders the satisfaction of target G2, then G 1 hinders G2.

4. Conflict dependence before goal

Definition: If:

The satisfaction of (1)g 1 excludes the satisfaction of G2, and

(2) 2) The satisfaction of G2 does not include the satisfaction of G 1.

Then there is a conflict between the targets G 1 and G2.

5. Target equivalence

Definition: If:

The satisfaction of (1)g 1 leads to the satisfaction of G2, and

(2) The satisfaction of 2)G2 leads to the satisfaction of G 1.

Then the target G 1 and G2 are equivalent.

Attribute composition of target description template:

1. Briefly describe the target.

Use active voice

3. Accurately describe the intention of stakeholders

4. Decompose high-level goals into more specific sub-goals.

5. Explain the value created by the goal.

6. Describe the reasons for introducing the target.

7. Avoid defining unnecessary constraints

Target model:

The AND OR tree and AND OR graph are based on AND OR decomposition and derived from artificial intelligence. Now they have been introduced into goal modeling to describe the mandatory and alternative sub-goal decomposition of goals.

1. and/or tree

2.AND/OR diagram

rely on

Objects in 1.i *

I * provided 5 objects:

Dependencies in 2.2.i *

3.3. Relationships between objects in I *

I* framework distinguishes three kinds of link relationships among four kinds of objects (goals, tasks, resources and soft goals):

4. Policy Dependence Model (SDM)

The Policy Dependency Model (SDM) describes the dependencies between different participants. It records which participants depend on which tasks, goals, soft goals and resources provided by other participants. SDM contains a set of participants (nodes) and a set of dependencies (edges) between participants. The following figure depicts a part of the Policy Dependency Model (SDM). It defines four kinds of dependencies between participants "car drivers" and "car manufacturers". These four dependencies are represented by four edges between participant nodes. The types of dependencies (target, resource, task and soft target) are marked on each dependency edge. The direction of the edge is indicated by the direction of the letter "D" marked on the edge (in the figure below, the direction of dependency ④ is different from that of dependencies ①-③).

This is a kind of goal dependence. It means that "car drivers" (dependents) rely on "car providers" (dependents) to achieve the goal of "avoiding accidents". The following figure further describes the details of this dependency in the strategic principle model (SRM).

(2) Task dependence refers to that the "automobile driver" relies on the "automobile manufacturer" in order to complete the task of "driving a certain distance".

(3) Resource dependence means that the "automobile driver" depends on the resource "automobile" provided by the "automobile manufacturer".

④ The soft goal dependence here refers to the soft goal that "automobile manufacturers" rely on "automobile drivers" to achieve "high driver satisfaction".

5. Strategic principle model

The strategic principle model describes the internal principle structure of each participant.

① The dotted line (participant boundary) defines the boundary of the internal principle structure of the participant "driver".

② The task of "safe driving from A to B" is divided into three task decomposition links: the soft goal of "driving pleasure" and the other two goals of "accident-free driving" and "personal and life safety protection".

③ The contribution link between the task of "observing the speed limit" and the soft target of "driving at high speed" is marked with a negative sign. This means that the task of "observing the speed limit" has a negative impact on the satisfaction of the soft goal of "driving at high speed".

④ Through the task decomposition link, the task of the participant "automobile manufacturer" is refined into the goal of "reducing the number of accidents" and "reducing personal injury" and the soft goal of "low development cost".

⑤ Automobile manufacturers have a soft goal of "excellent brand reputation". The task of "making safe cars" has had a positive impact on this soft goal. This contribution link shows a positive impact.

⑥ The tasks of "informing the driver of possible collision" and "making up for the driver's mistakes" are linked with the goal of "reducing the number of accidents" through two purposes, indicating that both tasks (means) have the goal of reducing the number of accidents. Method links from different tasks to the same goal usually indicate that there are multiple ways to achieve the goal.

⑦ The contribution link from the tasks "Inform the driver of possible collision" and "Make up the driver's mistake" to the soft target "Low development cost" is marked with a negative sign, indicating that the satisfaction of these two tasks is negative.

Extract, standardize and analyze objectives, requirements, scenarios and responsibilities.

1. Target and subject

2. Target relationship

How to choose a modeling language?