response system analysis design

refer to the attached document and write two responses 

Write a response for this two different posts

Post 1

(Khenedye)A data flow diagram is generally a graphic representation of system or a piece of a system. The diagrams usually encompass a series of data flows, sources, processes, destinations, and stores which can all be described and depicted using symbols. Systems can be described from the point of view of the data and what’s being trailed through the system with four symbols to spare. With that being said, data flow diagrams have the ability to project parallel activity. If a standard or original symbol was to put a limit on communication, presentation graphs would then be used in its place which could better representation with symbols of people, files, terminals, and different documents included, and would later be used to talk about a system with users. When using a use case diagram shows any of the use cases you may or may not have in your system, any actors you may have, and in what way they would be related within the program. The case system plays a key role in a system due to it being a piece that provides a high functioning system. An actors is simply defined as anyone and anything that is apart or plays any type of part in the system that is being built. Data flow diagrams differ from use case diagrams because it allows it makes data more understandable and readable about the software requirements. It’s also very good at showing incoming data and what the out come will be at the end.

 For use case diagrams, they are used to show the model the system or subsystem on any application. This particular diagram generally shows the functionality of a system and gives people a easier view of HOW things are operating. The whole purpose of the make it easier for the customer to understand what the users are doing and the whole process behind the product. 

Valacich, J. S., George, J. F., & Hoffer, J. A. (2015). Essentials of Systems Analysis and Design.Hoboken: Pearson Education Inc.

Post 2

(Melanie)A data-flow diagram is a common process model that illustrates the movement of data between external entities and processes and data stores within a system.  (Valacich.)  Data-flow diagrams easily allow for business processes to be decomposed into subprocesses.  

A use-case diagram shows actors and use-cases for a system – actors being external entities that interact with the system and use cases representing sequences of related actions initiated by actors.  (Valacich.)  Use-case modeling is done in the early stages of system development to analyze the functional requirements of a system; it is an iterative process that does not require developers to understand how the functional requirements of the system will be implemented.  

Although both diagrams show interactions between external entities and the system, data-flow diagrams focus on the data and processes while use-case diagrams focus more on the interactions between the system and external entities. Data-flow diagrams are not concerned with any data processing that occurs inside the source/sink (the external entities) because this is outside of the system, while use-case diagrams favor the interactions with the external entity and are not concerned with the specifics of internal processes. 

The use-case diagram should be used for communicating with the business users because the intended users of the system are a critical part of the process of creating a use-case diagram.  During the requirements analysis stage, an analyst sits down with the users to determine the desired functions of the systems, represented as use-cases.  (Valacich.)  It is therefore simple to conclude that a use-case diagram is a strong choice of model to use for communicating with business users.

The data-flow diagram should be used for communicating with the software developers because data-flow diagrams illustrate the movement of data within the system.  Data-flow diagrams are considered important tools for analysis and communication for information systems professionals that can “increase software development productivity.”  (Valacich.)  

References:

Valacich, J. S., George, J. F., & Hoffer, J. A. (2015). Essentials of Systems Analysis and Design (Sixth). Pearson Education Limited.