... system has low usability.I. Concept of User Interface •The user interface is the part of the system that you see, hear and feel (look and feel) –Other parts of the system are hidden to you, ... problem =Missing functionality, task failure, or cumbersome- to many users Overview of User Interface Design Dr. Lam Thu BUISoftware Engineering Department2. Choosing the numbers•We have more ... seconds)–security (e.g. preventing hacker attacks)–ease of use (often called usability)–maintainability (easy to maintain the program)–. . . Design of user interfaces: Example•Assume that the system...