Formal specification for a clinical cyclotron control system
Conference proceedings on Formal methods in software development
FM 89: assessment of formal methods for trustworthy computer systems
ICSE '90 Proceedings of the 12th international conference on Software engineering
Software Requirements Analysis for Real-Time Process-Control Systems
IEEE Transactions on Software Engineering
The Z notation: a reference manual
The Z notation: a reference manual
An introduction to formal specification and Z
An introduction to formal specification and Z
A survey of object orientation in Z
Software Engineering Journal - Object-oriented systems
Feedback Control of Dynamic Systems
Feedback Control of Dynamic Systems
Software Development with Z: A Practical Approach to Formal Methods in Software Engineering
Software Development with Z: A Practical Approach to Formal Methods in Software Engineering
Formal Specification and Development of Control System Input/Output
Proceedings of the Z User Workshop
Formal Specifications as Reusable Frameworks
VDM '90 Proceedings of the Third International Symposium of VDM Europe on VDM and Z - Formal Methods in Software Development
Formal methods: state of the art and future directions
ACM Computing Surveys (CSUR) - Special ACM 50th-anniversary issue: strategic directions in computing research
Formalizing space shuttle software requirements: four case studies
ACM Transactions on Software Engineering and Methodology (TOSEM)
Research Frontiers in Object Technology
Information Systems Frontiers
The use of industrial-strength formal methods
COMPSAC '97 Proceedings of the 21st International Computer Software and Applications Conference
An Agenda for Specifying Software Components with Complex Data Models
SAFECOMP '98 Proceedings of the 17th International Conference on Computer Safety, Reliability and Security
Improving design dependability based on the TRON loose standardization approach
TRON '95 Proceedings of the The 12th TRON Project International Symposium, 1995
Design Fault Tolerance in Operating Systems Based on a Standardization Project
FTCS '95 Proceedings of the Twenty-Fifth International Symposium on Fault-Tolerant Computing
Visualizing graphical and textual formalisms
Information Systems
A formal specification in B of a medical decision support system
ZB'03 Proceedings of the 3rd international conference on Formal specification and development in Z and B
An intuitive approach to determine test adequacy in safety-critical software
ACM SIGSOFT Software Engineering Notes
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This paper presents a formal specification in the Z notation for a safety-critical control system. It describes a particular medical device but is quite generic and should be widely applicable. The specification emphasizes safety interlocking and other discontinuous features that are not considered in classical control theory. A method for calculating interlock conditions for particular operations from system safety assertions is proposed; it is similar to ordinary Z precondition calculation, but usually results in stronger preconditions. The specification is presented as a partially complete framework that can be edited and filled in with the specific features of a particular control system. Our system is large but the specification is concise. It is built up from components, subsystems, conditions and modes that are developed separately, but also accounts for behaviors that emerge at the system level. The specification illustrates several useful idioms of the Z notation, and demonstrates that an object-oriented specification style can be expressed in ordinary Z.