Evaluation of a specification approach for vehicle functions using activity diagrams in requirements documents

Rising complexity of systems has long been a major challenge in requirements engineering. This manifests in more extensive and harder to understand requirements documents. At the Daimler AG, an approach is applied that combines the use of activity diagrams with natural language specifications to specify vehicle functions. The approach starts with an activity diagram that is created to get an early overview. The contained information is then transferred to a textual requirements document, where details are added and the behavior is refined. While the approach aims at reducing efforts needed to understand a function’s behavior, the application of the approach itself causes new challenges on its own. By examining existing specifications at Daimler, we identified nine categories of inconsistencies and deviations between activity diagrams and their textual representations. This paper extends a previous case study on the subject by presenting additional data we acquired. Our analysis indicates that a coexistence of textual and graphical representations of models without proper tool support results in inconsistencies and deviations

Spacelab software development and integration concepts study report, volume 1

The proposed software guidelines to be followed by the European Space Research Organization in the development of software for the Spacelab being developed for use as a payload for the space shuttle are documented. Concepts, techniques, and tools needed to assure the success of a programming project are defined as they relate to operation of the data management subsystem, support of experiments and space applications, use with ground support equipment, and for integration testing

Assessment of the NASA Flight Assurance Review Program

The NASA flight assurance review program to develop minimum standard guidelines for flight assurance reviews was assessed. Documents from NASA centers and NASA headquarters to determine current design review practices and procedures were evaluated. Six reviews were identified for the recommended minimum. The practices and procedures used at the different centers to incorporate the most effective ones into the minimum standard review guidelines were analyzed and guidelines for procedures, personnel and responsibilies, review items/data checklist, and feedback and closeout were defined. The six recommended reviews and the minimum standards guidelines developed for flight assurance reviews are presented. Observations and conclusions for further improving the NASA review and quality assurance process are outlined

Early aspects: aspect-oriented requirements engineering and architecture design

This paper reports on the third Early Aspects: Aspect-Oriented Requirements Engineering and Architecture Design Workshop, which has been held in Lancaster, UK, on March 21, 2004. The workshop included a presentation session and working sessions in which the particular topics on early aspects were discussed. The primary goal of the workshop was to focus on challenges to defining methodical software development processes for aspects from early on in the software life cycle and explore the potential of proposed methods and techniques to scale up to industrial applications

Systems engineering and integration and management for manned space flight programs

This paper discusses the history of SE&I management of the overall program architecture, organizational structure and the relationship of SE&I to other program organizational elements. A brief discussion of the method of executing the SE&I process, a summary of some of the major lessons learned, and identification of things that have proven successful are included

What is a good textual representation of activity diagrams in requirements documents?

The use of graphical models has become a widely adopted approach to specify requirements of complex systems. Still, in practice, graphical models are often accompanied by textual descriptions to provide more detail, because of legal considerations, and to enable stakeholders with different backgrounds to understand a requirements document. One of our industry partners (Daimler AG) uses activity diagrams to specify vehicle functions in combination with a textual representation thereof in their requirements documents. Since graphical and textual representations serve different purposes, it is not obvious how textual representations of activity diagrams should be structured. In this paper, we present different textual representations of activity diagrams for use in requirements documents. The representation currently in use is presented as well as four alternatives. For each representation, we discuss advantages and disadvantages. To evaluate the representations, we asked five stakeholders of one system to create a preference ranking of the representations. The resulting ranking showed that the currently used representation is not considered to be the best possible option. The stakeholders’ favorite textual representation emphasizes structural similarity with the activity diagram, which however does not resemble the diagram’s structure exactly

Data management study, volume 5. Appendix A - Contractor data package technical description and system engineering /SE/ Final report

Technical description and systems engineering contractor data package for Voyager spacecraf

The uses of process modeling : a framework for understanding modeling formalisms

There is wide-spread recognition of the urgent need to improve software processes in order to improve the performance of software organizations. Process models are essential in achieving understanding and visibility of processes and are important for other uses including the analysis of processes for improvement. It has been increasingly difficult to compare and evaluate the variety of process modeling formalisms that have appeared in recent years without a clear understanding of precisely for what they will be used. The contribution of this paper is to provide an understanding and a fairly comprehensive catalog of the applications of process modeling for which formalisms may be used. The primary mechanism for doing this is a guided tour of the literature on process modeling supplemented by recent industrial experience. In the paper, basic definitions concerning processes, process descriptions and process modeling are reviewed and then uses of process modeling are surveyed under the following headings: communication among process participants, construction of new processes, control of processes, process· analysis, and process support by automation. Comments are offered on paradigms for process modeling formalisms and directions for future work to permit evolution of a discipline of process engineering are given

The systems engineering overview and process (from the Systems Engineering Management Guide, 1990)

The past several decades have seen the rise of large, highly interactive systems that are on the forward edge of technology. As a result of this growth and the increased usage of digital systems (computers and software), the concept of systems engineering has gained increasing attention. Some of this attention is no doubt due to large program failures which possibly could have been avoided, or at least mitigated, through the use of systems engineering principles. The complexity of modern day weapon systems requires conscious application of systems engineering concepts to ensure producible, operable and supportable systems that satisfy mission requirements. Although many authors have traced the roots of systems engineering to earlier dates, the initial formalization of the systems engineering process for military development began to surface in the mid-1950s on the ballistic missile programs. These early ballistic missile development programs marked the emergence of engineering discipline 'specialists' which has since continued to grow. Each of these specialties not only has a need to take data from the overall development process, but also to supply data, in the form of requirements and analysis results, to the process. A number of technical instructions, military standards and specifications, and manuals were developed as a result of these development programs. In particular, MILSTD-499 was issued in 1969 to assist both government and contractor personnel in defining the systems engineering effort in support of defense acquisition programs. This standard was updated to MIL-STD499A in 1974, and formed the foundation for current application of systems engineering principles to military development programs