Software Engineering (IV)

Steps of the Feasibility study
1) Review the system size and objectives;
2) Study the systems currently in use;
3) The high-level logic model of the new system (data Flow Diagram and dictionary) is derived.
4) redefine the problem;
5) Export and evaluate the alternative solution (physical solution);
6) Recommended action plan;
7) draft development plan;
8) Write a document to submit a review.

Data dictionary

Data dictionary: A collection of definitions of all the elements contained in a dataflow diagram;

At the stage of feasibility study, the data flow diagram is the logical model of the system.

The data dictionary should define the following elements:
1) data stream;
2) Data elements (data flow components);
3) data storage;
4) processing.

The contents of the data dictionary

Information about data elements in a data dictionary:
General information (name, alias, etc.)
Defined
Use characteristics (range of values, frequency, etc.)
Control information (source, user, etc.)

Ways to define Data
1) Data element dictionary definition
The basic contents of the definition are:
A Data element number, name and meaning;
B data type and length;
C reasonable value;
D Other content, such as its logical relationship with other data.
2) Data Flow dictionary definition
The basic contents of the definition are:
A Data stream number and name;
B The source of the data stream;
C Data flow destination;
D The composition of the data stream;
E. Liquidity
F. Peak.
3) data storage dictionary definition
The basic contents of the definition are:
A Data storage number and name;
B The composition of the data storage;
C Other requirements.
4) Data processing dictionary definition
The basic contents of the definition are:
A Data processing number and name;
B Simple description;
C Input/output;
D function description;
E. About data storage.

The purpose of the data dictionary
1. As an important tool in the analysis phase;
2. The control information of the data element is very useful;
3. Contribute to the development of the database.

Implementation of data dictionary
To implement a data dictionary:
1) procedure processing;
2) card-type manual writing;

Cost/benefit Analysis

Cost estimates
1) Code line technology
Software cost = Average Cost per line of code x estimated total number of source lines
2) Task Decomposition technology
The Software development project is decomposed into several relatively independent tasks, estimating the cost of each individual task separately:
Individual task cost = manpower estimate required by task X average monthly wage per person;
Total cost estimate of software development project = Sum of individual task cost estimates.
The common approach is to divide the tasks by the development phase, and the percentage of manpower required for each development phase in a typical environment is roughly as follows:

3) automatic estimation of cost technology
Estimation of software tools with automatic cost estimation.

Feasibility Analysis Report
This paper illustrates the feasibility of the implementation of the Software development Project on the technical, economic and social factors, and discusses the reasons for the selected embodiments in order to reasonably meet the various possible implementation options for the development goals.
Project Development Plan

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Software Engineering (IV)