The principle of increasing module independence is

The principle of improving module independence is: low coupling, high aggregation.

Module independence means that each module accomplishes only the independent sub-functions required by the system, and has minimal connection with other modules and simple interfaces.

Module independence is a measure of the relationship between parts and modules within a module, measured by cohesion and coupling. Software with independent modules is easier to develop. This is due to the ability to partition functionality and to simplify interfaces, an advantage that is especially important when many people are working together to develop the same software.

Independent modules are easier to test and maintain. This is because relatively little effort is required to modify the design and program, errors are less likely to propagate, and modules can be "plugged in" when additional functionality is needed. In short, module independence is the key to good design, and design is the key to software quality.

Measurement:

Coupling is a measure of the degree of interconnection between modules within a software structure. The strength of the coupling depends on the complexity of the interfaces between the modules, the way the modules are called, and the information that passes through the interfaces. Specific criteria for distinguishing the strength of inter-module coupling are as follows: non-direct coupling, data coupling, tagging coupling, control coupling, external coupling, public *** environment coupling, and content coupling.

In short, coupling is an important factor affecting the complexity of software. The principles that should be adopted are: use data coupling as much as possible, use control coupling sparingly, limit the scope of public *** environment coupling, and do not use content coupling at all.

Cohesion marks the degree to which elements within a module are tightly integrated with each other, and it is a natural extension of the concepts of information hiding and localization. Simply put, ideally cohesive modules do only one thing. Contingent cohesion, logical cohesion, temporal cohesion, process cohesion, communication cohesion, sequential cohesion, and functional cohesion.