Ch 06

Question 1

EO 6.1.1

What is the term “model” and the properties of models

Answer 1

A model is an abstraction of an existing reality or a reality to be created

Models have three important properties:

1. Representation property: models map reality
2. Reduction property: models reduce the represented reality
3. Pragmatic property: models are constructed for a special purpose

Question 2

EO 6.1.2

The definition elements of conceptual modeling

Answer 2

Conceptual modeling languages are used for the modeling of conceptual models, which are defined by their syntax (modeling elements and their valid combinations) and semantics (meaning of the modeling elements).

Question 3

EO 6.1.3

Advantages of requirements modeling

Answer 3

following advantages:

Information presented in pictures is quicker to understand and memorize

Requirements models allow the targeted modeling of one perspective on the requirements

By defining the modeling language for the particular purpose, an appropriate abstraction of reality can already be specified

Question 4

EO 6.2.1

Importance of goal requirement engineering

Answer 4

A goal describes an intention of a stakeholder. Such intentions typically concern characteristic features of the system to be developed or of the associated development project. Goals can be documented both in natural language and in the form of models.

Question 5

EO 6.2.2

The two types of goal decomposition

Answer 5

“AND decomposition” (all sub-goals must be fulfilled in order to fulfill the higher goal (super-goal)

“OR decomposition” (at least one sub- goal must be fulfilled in order to fulfill the higher goal (super-goal)

Question 6

in use cases, what is the difference between include and extend

Answer 6

Include The use case “navigate to destination” is related to the use cases “input destination” and “retrieve current position” via an include relation. The relationship depicts that the interaction steps defined in the use cases “input destination” and “retrieve current position” are contained in the use case “navigate to destination.

Extend The extend relation between the use cases “download traffic information” and “navigate to destination” defines that the interaction steps defined in the use case “download traffic information” are included in the interaction steps of the use case “navigate to destination” if a certain condition, such as “avoid congestion”, is met. The extension point “avoid congestion” depicts the step in the use case “navigate to destination” at which the additional interaction steps are being executed.

Question 7

EO 6.5.1

What is the focus of the data perspective on requirements

Answer 7

entity-relationship diagrams are used for modeling the data perspective because they display the structure of an object of an universe of discourse by means of entity types and relation types.

Question 8

EO 6.6.1

What is the focus of the functional perspective on requirements

Answer 8

“The functional perspective of requirements deals with the transformation of input data received from the environment into output data released into the environment of the system. ”

Question 9

EO 6.7.1

What is the focus of the behavioral perspective on requirements

Answer 9

“To model the dynamic behavior of a system, modeling approaches based on automata theory are typically employed. The definition of a finite-state automaton comprises a set of states and a set of transitions that, dependent on the current state of the automaton, are performed given some event.”