From safety analysis to software requirements

Software for safety critical systems must deal with the hazards identified by safety analysis. This paper investigates, how the results of one safety analysis technique, fault trees, are interpreted as software safety requirements to be used in the program design process. We propose that fault tree analysis and program development use the same system model. This model is formalized in a real-time, interval logic, based on a conventional dynamic systems model with state evolving over time. Fault trees are interpreted as temporal formulas, and it is shown how such formulas can be used for deriving safety requirements for software components     

Breathing architecture: Conceptual architectural design based on the investigation into the natural ventilation of buildings

This study explores architectural design by examining air, fluid mechanics, and the natural ventilation of buildings. In this context, this research introduces a new way of dealing with the process of architectural synthesis. The proposed way can be used either to create new architectural projects or to rethink existing ones. This study is supported by previous investigation into the natural ventilation of buildings via computational and laboratory simulation (Stavridou, 2011; Stavridou and Prinos, 2013). The investigation into the natural ventilation of buildings provides information and data that affect architectural design through various parameters. The parameters of architectural synthesis that are influenced and discussed in this paper are the following: (i) inspiration and analogical transfer, (ii) initial conception of the main idea using computational fluid dynamics (digital design), (iii) development of the main idea through an investigatory process toward building form optimization, and (iv) form configuration, shape investigation, and other morphogenetic prospects. This study illustrates the effect of natural ventilation research on architectural design and thus produces a new approach to the architectural design process. This approach leads to an innovative kind of architecture called “breathing architecture.”     

Gordon's computer: A hardware verification case study in OBJ3

The use of the algebraic specification language OBJ3 [26] in hardware verification has been demonstrated on a number of small examples [62, 20, 63] and some large but regular structures [12, 11]. In this paper, we show that the approach can also be used for specifying and verifying large, irregular structures. We specify and partially verify Gordon's computer, a simple microprocessor. We believe that this is the largest hardware verification case study undertaken with OBJ3 so far.     

The formal specification of safety requirements for storing explosives

In this paper we consider the current practices involved in the storage of explosive articles and substances. In the spirit of Defence standard 00-55, we formalize the safety requirements of the ACS software which is used to manage certain MOD holdings in the United Kingdom using the specification language VDM. We also prove some properties of these safety requirements and comment on a similar OBJ3 specification.     

Decomposition in Real-Time Safety-Critical Systems

Existing formal techniques for the development of software for use in safety-critical systems do not adequately address non-functional system requirements such as those involving timing. In this paper we describe a formal development method in which specifications may be decomposed into unexceptional programs whilst preserving the functional and timing requirements of the specification. We illustrate the method with a speed monitoring example.     

Formal requirements analysis of an avionics control system

The authors report on a formal requirements analysis experiment involving an avionics control system. They describe a method for specifying and verifying real-time systems with PVS. The experiment involves the formalization of the functional and safety requirements of the avionics system as well as its multilevel verification. First level verification demonstrates the consistency of the specifications whilst the second level shows that certain system safety properties are satisfied by the specification. They critically analyze methodological issues of large scale verification and propose some practical ways of structuring verification activities for optimizing the benefits