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Structured Systems Analysis and Design Method. SSADM with ConceptDraw DIAGRAM

Structured Systems Analysis and Design Method (SSADM) is the method which is used at projecting and analysis of information systems. This method was developed for government of Great Britain in the beginning of 80th of the past century. It was accepted as the national standard of Great Britain for information systems development in 1993. Thus SSADM usage is expedient for those who work with governmental organizations as this method is a standard for these organizations.

SSADM is based on the data flow diagrams. At the early stages of projecting at description of models (functional, informational and event-trigger) the top-down method is used.

At the description of data flows out of the system and into the system DFD, which denote boundaries of the system, are used.

At the description of data models LDS (Logical Data Structure) diagrams are used. LDS describes which data the system operates with. It is created for existing system and is added at the development of the new one.

For modelling events, happened in the system, ELN (Entity Life History) diagrams are used. These diagrams support states indications and the possibility of description not only consecutive but parallel or reiterative events and also description of the choice of events course. ELN describes how data change in the system in the course of time at different variants of events.

Thus, the most important SSADM elements are flows modelling with the help of DFD, data logic modelling with the help of LDS and description of entities behavior.

Analysis, projecting and documenting of information system accordingly to SSADM involves 6 main stages. Each stage is divided into several steps, which define tasks that should be fulfilled at the given stage. The system is studied for getting system requirements. Detailed project is created on the logic level and then transformed into physical project.

SSADM stages:

  • Analysis of the existing system or estimation of practicability. It involves the analysis of the existing system and creation of DFD for visualization of known problems and system description. If the system is developed from the beginning than the projecting starts from definition of new system requirements.
  • Requirements definition. On the basis of available data about the system new functions, which the system must execute are defined. Also boundaries of the future system and data which will be processed by the system are defined. Infological model of requirements is constructed.
  • Definition of technical requirements and device equipment cost. Definition of the expected profit with the introduction of new functions.
  • Development of logical data model. Specification of the list of functional requirements. After development of the logical project the adding of new requirements on SSADM is forbidden. Only correction of the existing requirements, their specification and concrete definition are allowed.
  • Projecting of logical requirements. Specification of requirements.
  • Physical projecting. Physical information model and specification to program elements are developed and optimized. Specifications to program elements are specified and documentation is drawn up.

The advantages of SSADM are the precise definition and support of so-called “non functional requirements”. Such requirements define the level of the quality with which the system must execute its functions. For example, access limitations, the mean time of lifelength to denial, time of the response, safety requirements, etc.

In comparison with other methods of information system projecting, particularly with E. Yordon and A. Young methods, SSADM is characterized with presence of clear consecution of steps at projecting.

Structured Systems Analysis and Design Method solution

Structured Systems Analysis and Design Method

Pic.1. Structured Systems Analysis and Design Method solution

The following features make ConceptDraw DIAGRAM the best Data Flow Diagram software:

  1. You don't need to be an artist to draw professional looking diagrams in a few minutes.
  2. Large quantity of ready-to-use vector objects makes your drawing diagrams quick and easy.
  3. Great number of predesigned templates and samples give you the good start for your own diagrams.
  4. ConceptDraw DIAGRAM provides you the possibility to use the grid, rules and guides. You can easily rotate, group, align, arrange the objects, use different fonts and colors to make your diagram exceptionally looking.
  5. All ConceptDraw DIAGRAM documents are vector graphic files and are available for reviewing, modifying, and converting to a variety of formats: image, HTML, PDF file, MS PowerPoint Presentation, Adobe Flash, MS Visio.
  6. Using ConceptDraw STORE you can navigate through ConceptDraw Solution Park, managing downloads and updates. You can access libraries, templates and samples directly from the ConceptDraw STORE.
  7. If you have any questions, our free of charge support is always ready to come to your aid.

All computer networks differ by various params, and their size is one of them. As global area networks are the biggest, personal area (PAN) networks are the smallest. Personal computers, smartphones and other devices that have possibility to connect to Internet form a personal network. This diagram was created using ConceptDraw Computer Network Diagrams to represent a typical components of Personal area network. A personal area network (PAN) is the connection of IT devices around an individual person. This sample of personal area network involves a notebook, a personal digital assistant (PDA), and a portable printer. Commonly a PAN contains such wireless devices as mouse, keyboard, smartphone and tablet. A wireless connection is typical for a PAN.Personal area (PAN) networks
Picture: Personal area (PAN) networks. Computer and Network Examples
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Data Flow Diagram is used to depict the flow of data through the system, where it enters and exits the system, as well as where it is stored. To simplify the process of drawing a data flow diagram (DFD), ConceptDraw DIAGRAM provides a DFD Library - design elements that will help you make your diagram as informative, streamlined and understandable as possible. Data flow diagrams are useful to create a general overview of the system or to document major data flows. Here are the library of symbols used in data flow diagrams (DFD). Data Flow diagrams are graphic means of business process visualization. Any business process may involve the data transfer. It can be easily shown using data flow diagrams. DFDs are used to represent the processing and transformation of data within a business process. One can find out the Vector library of DFD symbols, that is a component of ConceptDraw solution for Data Flow Diagramming and is welcome to use in as addition to the common Conceptdraw DIAGRAM diagramming facilities.DFD Library — Design elements *
Picture: DFD Library — Design elements
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When you are a beginner in software development, you make a lot of mistakes. Developing logical models, or data flow diagrams is a way to see the the whole project and all the processes clearly. And some novices, unfortunately for them, miss modeling stage at the beginning of project life cycle, and get into troubles as the project grows. This image represents the data flow diagram applying symbols of Yourdon and Coad notation. This DFD depicts the data flow inside an organization department deals with receivables. The icons of standard Yourdon and Coad notation provides possibility to draw professional looking and well- readable DFD for business documentation. This data flow diagram was designed with the help of ConceptDraw DIAGRAM and its Data Flow Diagrams solution. The solution delivers three vector graphic libraries including elements of Yourdon and Coad and Gane-Sarson notations.Data Flow Diagram Process *
Picture: Data Flow Diagram Process
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The Rapid UML solution from Software Development area of ConceptDraw Solution Park includes 13 vector stencils libraries for drawing the UML 2.4 diagrams using ConceptDraw DIAGRAM diagramming and vector drawing software.Design Elements for UML Diagrams *
Picture: Design Elements for UML Diagrams
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When studying a business process or system involving the transfer of data, it is common to use a Data Flow Diagram (DFD) to visualize how data are processed. Being initially used exclusively in regards to the flow of data through a computer system, now DFDs are employed as the business modeling tools. They are applied to describe the business events and interactions, or physical systems involving data storage and transfer. ConceptDraw DIAGRAM is a powerful Data Flow Diagram software thanks to the Data Flow Diagrams solution from the Software Development area of ConceptDraw Solution Park.Data Flow Diagram Software *
Picture: Data Flow Diagram Software
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Use Case Diagram Taxi Service UML. This sample was created in ConceptDraw DIAGRAM diagramming and vector drawing software using the UML Use Case Diagram library of the Rapid UML Solution from the Software Development area of ConceptDraw Solution Park. This sample shows the work of the taxi service and is used by taxi stations, by airports, in the tourism field and delivery service.UML  Block Diagram *
Picture: UML Block Diagram
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