Extensions to Pattern Formats for Cyber Physical Systems

Cyber Physical Systems (CPSs) are becoming not only increasingly complex but also increasingly important. These systems have evolved from self-contained monolithic systems operating in a well-defined environment, to large-scale Cyber-Physical Systems including multiple interacting components. In this paper we will refer to both as CPSs. Due to the inherent complexity of the physical environments within which they operate and the ever changing operational and context conditions of these environments, CPSs need to be able to adapt in a semior fully autonomic manner. At the same time, in the course of adapting themselves, they need to satisfy key quality, security and privacy (QSP) requirements and be resilient to known and unknown related threats. Engineering CPSs with such capabilities is a challenging problem that requires expert knowledge. Our approach to addressing this problem is based on the use of QSP-preserving patterns, i.e., patterns that encode proven design and engineering solutions for CPSs that need to preserve particular QSP properties. We argue that existing pattern formats miss some essential features of these systems. As a step towards the realization of this approach, in this paper we present a new pattern format that enables representing most important characteristics of QSP preserving patterns for CPS. Our format provides an initial basis for defining a full pattern language for engineering QSP preserving CPS.