Gantt Chart, IPO Chart, DFD Chart
1. Gantt Chart
Gantt chart ( Gantt chart) is also known as bar chart, bar chart ( Bar chart). It uses bar graphs to show how projects, schedules, and other time-dependent system progress interrelationships progress over time. Named after the author, Henry Lawrence Gantt ( Henry Laurence Gantt).
Gantt charts graphically represent the sequence and duration of specific projects with a list of activities and a timescale. A line graph with time on the horizontal axis, projects on the vertical axis, and lines planned and actual completion during the period. Visualize when plans are in progress, progress versus requirements. It is convenient for managers to figure out the remaining tasks of the project and evaluate the progress of the work.
Gantt chart is one of the earliest tools to link activities with time for the purpose of job sorting, helping companies describe the use of resources such as work centers and overtime work.
Gantt chart contains the following three meanings:
1. Display activities in the form of graphs or tables;
2. A general method of displaying progress;
3. Calendar days and durations are included in the construction, and weekends and holidays are not counted in the progress.
According to different contents, Gantt charts are divided into five forms: plan chart, load chart, machine idle chart, personnel idle chart and progress chart.
2. IPO map
IPO refers to the input (Input), processing (Processing), and output (Output) of the transformation structure in the structural design. IPO diagram is a tool for detailed design of each module. It is the abbreviation of input processing output ( INPUT PROCESS OUTPUT) diagram. It is a tool initiated and perfected by IBM Corporation of the United States. In the process of forming the module structure diagram of the system, a large number of modules are generated, and the developer should write a description for each module during the detailed design. The IPO diagram is an important tool used to illustrate the input, output data and data processing of each module.
IPO diagram is the abbreviation of input/processing/output diagram. It is a graphical tool proposed by IBM in the United States, which can easily describe the relationship between input data, processing data and output data.
The basic symbols used in the IPO chart are few and simple, so it is easy to master the use of this tool. Its basic form is to list the relevant input data in the left box, the main processing in the middle box, and the resulting output data in the right box. The order of processing is listed in the processing box, but these basic notations are not sufficient to describe the details of how processing is performed.
3. DFD diagram
DFD (Data Flow Diagram) diagram is a data flow diagram or data flow diagram. It expresses the logical function of the system graphically from the point of view of data transmission and processing. The logical flow and logical transformation process of data within the system is the main expression tool of the structured system analysis method and a graphical method used to represent the software model. It is a functional model. For drawing DF maps, the global first and then the local are generally adopted. , first the whole, then the details, first the abstraction and then the concrete principle.
