Modeling with a sense of purpose

These days, practically everyone involved in developing software draws pictures that represent some aspect of the software or its requirements. They do this to improve their own understanding and, usually, to communicate that understanding to others. But all too often, the understanding is muddled and confused because the designer hasn't clearly established the picture's purpose or explained how others should interpret it. Surprisingly, this is true even when the designer uses an established modeling standard, such as the Unified Modeling Language (UML). The article looks at implementation, specification, and conceptual models in order to explain the intricacies of model based software design