Structured techniques for IMIS (Integrated Maintenance Information System) software development---a case study

Abstract

The AFHRL has a long term research project to develop an Integrated Maintenance Information System (IMIS). The project was initiated in 1979 and is expected to be completely by 1991. The objective of IMIS is to give maintenance technicians a very small size portable computer/display that will interface with on-aircraft systems and other computer systems to provide a single, integrated source of the information needed to perform maintenance on the line and in the shop. The system will display graphic instructions, provide intelligent diagnostic advice, provide aircraft battle damage assessment aids, analyze in-flight access and interrogate on-board built-in-test capabilities. It will also provide the technician with easy and efficient methods to receive work orders, report maintenance actions, order parts from supply, and offer complete computer-aided training lessons and simulations.The objectives of the study were to review and evaluate the requirements specifications and to make recommendations to accomplish total compatibility of IMIS with current and future requirements of the users with an emphasis on methodologies/tools for software requirements specification. The study concentrated on structured tools which could be used for IMIS. The various reports submitted by contractors and those developed in-house related to concepts of IMIS, feasibility aspects and information requirements of maintenance technicians were reviewed by the researcher, and it was observed that structured tools have not been used in defining user requirements or in development of software. The information requirements of maintenance technicians were presented using process flowcharts and narration. A great deal of mental effort is required to understand these charts. Checking for consistency and completeness of requirements is a formidable task when these charts are used.It was recommended that structured techniques should be used at the various phases of IMIS software development life cycle. They would provide efficient documentation of various phases and also lead to solutions in successive phases. They could also be used as management tools in assigning tasks to various contractors and in monitoring the progress of IMIS project. Some of the tools which could be used in the IMIS project are: Data Flow Diagrams, Structure Charts, Warnier-Orr Methodology, Nassi-Shneiderman Charts, Decision Tables, and Entity-Relationship Diagrams.It was also recommended that automated structured tools should be adapted as it is not possible to enforce uniformity and consistency if the documentation is done manually. An automated tool for DFD was obtained and some of the information requirements were presented through the DFD. An effort is in progress to select appropriate automated tools for various phases of IMIS life cycle.