A single adaptable user interface (ACll) which allows the user to switch between any number of different dialogue modes at any time-even in the middle of a command-can be useful to a variety of users who are neither beginners nor experts. It can also be used in applications where different dialogue modes are appropriate for the various parameters of a singie command. An implemented user interface management system (CIIMS) suggests the practicality of ACJIs and their automatic generation.

Many current compilers produce in some situations wrong error messages that mislead the user and harm his confidence in the system. It is demonstrated that a reliable and efficient syntax error handling system may be produced automatically by a compiler generator from the BNF specification of the language, and without any effort by the language implementor. This result is achieved in three ways: Some errors may not be diagnosed without knowledge of the intentions of the programmer. Some compilers employ a sophisticated analysis that attempts to capture these intentions, but which is not always successful. Such an elaborate analysis is not employed here, and instead a list of all the legal corrections is displayed, so that the programmer may readily select the right one. The recovery symbols are selected by a ‘careful’ algorithm resulting in a high probability for correct error recovery. The ‘honest’ error messages show also the parts of the code which could not be analysed correctly because of errors, and where more errors may exist. Efficiency is achieved by computing the recovery sets once and for all at compiler generation time, so that a fast error recovery at program compilation time is achieved. Experiments with erroneous programs suggest that the method compares well with the best compilers that we have seen, and is specially good at the avoidance of wrong error messages.

Faults in system requirements can be very harmful. It is therefore often required that the inspection achieves a high fault detection rate (FDR). To achieve this, a large number of inspectors is required. Large teams are known to be inefficient. Therefore, the N-fold requirements inspection method divides the inspectors into N small efficient teams. All teams inspect the same requirements document. Experiments with both information and real-time systems demonstrate that the different teams detect different faults such that they achieve together a higher FDR value. The analysis suggests that the FDR is primarily a function of the level of expertise of the inspectors and of the number of teams. A quite simple probabilistic model that matches the experimental results enables the prediction of the FDR as a function of these two parameters. A diagram based on the model enables a fast estimation of the FDR and of the most effective number of inspections teams money-wise. The model may also be employed for measuring the efficiency of requirement inspection methods.

No abstract

No abstract