cs240 week 8

1.Activity diagrams, which show the activities involved in a process or in data processing . 2.Use case diagrams, which show the interactions between a system and its environment. 3.Sequence diagrams, which show interactions between actors and the system and between system components. 4. Class diagrams, which show the object classes in the system and the associations between these classes. 5. State diagrams, which show how the system reacts to internal and external events.

what are 5 UML diagram types?

Context models simply show the other systems in the environment, not how the system being developed is used in that environment. Process models reveal how the system being developed is used in broader business processes.

what are the process perspective of context diagram?

1. As a means of facilitating discussion about an existing or proposed system Incomplete and incorrect models are OK as their role is to support discussion. 2. As a way of documenting an existing system Models should be an accurate representation of the system but need not be complete. 3. As a detailed system description that can be used to generate a system implementation Models have to be both correct and complete.

what are the 3 use of graphical models

Unified Modeling Language (UML).

what is uml ?

1.An external perspective, where you model the context or environment of the system. 2. An interaction perspective, where you model the interactions between a system and its environment, or between the components of a system. 3. organization of a system or the structure of the data that is processed by the system. 4. A behavioral perspective, where you model the dynamic behavior of the system and how it responds to events.

what are the 4 main system perspective ??

1. A model is an abstract view of a system that ignores system details. Complementary system models can be developed to show the system's context, interactions, structure and behavior. 2. Context models show how a system that is being modeled is positioned in an environment with other systems and processes. 3. Use case diagrams and sequence diagrams are used to describe the interactions between users and systems in the system being designed. Use cases describe interactions between a system and external actors; sequence diagrams add more information to these by showing interactions between system objects. 4. Structural models show the organization and architecture of a system. Class diagrams are used to define the static structure of classes in a system and their associations.

key points for week part 1

1.Actors : Medical receptionist, patient records system (PRS) 2.Description: A receptionist may transfer data from the MHC-PMS to a general patient record database that is maintained by a health authority. The information transferred may either be updated personal information (address, phone number, etc.) or a summary of the patient's diagnosis and treatment. 3.Data :Patient's personal information, treatment summary 4.Stimulus: User command issued by medical receptionist 5.Response: Confirmation that PRS has been updated 6.Comments:The receptionist must have appropriate security permissions to access the patient information and the PRS.

see the tabular description for use case

System boundaries are established to define what is inside and what is outside the system. They show other systems that are used or depend on the system being developed. The position of the system boundary has a profound effect on the system requirements. Defining a system boundary is a political judgment There may be pressures to develop system boundaries that increase / decrease the influence or workload of different parts of an organization.

what are the system boundaries for context diagrams?

1 Class diagrams are used when developing an objectoriented system model to show the classes in a system and the associations between these classes. 2 An object class can be thought of as a general definition of one kind of system object . 3 An association is a link between classes that indicates that there is some relationship between these classes. 4.When you are developing models during the early stages of the software engineering process, objects represent something in the real world, such as a patient, a prescription, doctor, etc.

what is class diagram?

Context models are used to illustrate the operational context of a system - they show what lies outside the system boundaries.

what is context model used for ?

1. Structural models of software display the organization of a system in terms of the components that make up that system and their relationships. 2. Structural models may be static models, which show the structure of the system design, or dynamic models, which show the organization of the system when it is executing. 3. You create structural models of a system when you are discussing and designing the system architecture.

what is structural models?

Modeling user interaction is important as it helps to identify user requirements. Modeling system-to-system interaction highlights the communication problems that may arise. Modeling component interaction helps us understand if a proposed system structure is likely to deliver the required system performance and dependability. Use case diagrams and sequence diagrams may be used for interaction modeling.

what is system modelling used for?

System modeling is the process of developing abstract models of a system, with each model presenting a different view or perspective of that system. System modelling helps the analyst to understand the functionality of the system and models are used to communicate with customers.

what is system modelling?

1. Sequence diagrams are part of the UML and are used to model the interactions between the actors and the objects within a system. 2. A sequence diagram shows the sequence of interactions that take place during a particular use case or use case instance. 3. The objects and actors involved are listed along the top of the diagram, with a dotted line drawn vertically from these.

what is the use of sequence of diagrams?

Use cases were developed originally to support requirements elicitation and now incorporated into the UML. Each use case represents a discrete task that involves external interaction with a system. Actors in a use case may be people or other systems. Represented diagramatically to provide an overview of the use case and in a more detailed textual form.

what is use cases modelling used for ?

Models of the existing system are used during requirements engineering. They help clarify what the existing system does and can be used as a basis for discussing its strengths and weaknesses. These then lead to requirements for the new Models of the new system are used during requirements engineering to help explain the proposed requirements to other system stakeholders. Engineers use these models to discuss design proposals and to document the system for implementation.

while trying to create a new model for an existing model what is the old model used for ?