Assessing the effect of failure severity, coincident failures and usage-profiles on the reliability of embedded control systems

Abstract

Very faithful but intractable Faithful but relatively intractable Relatively faithful and tractable Unfaithful but very tractable System Under Study (Proposed / Exisitng) REAL SYSTEMChallenges: (1) large state space, (2) model stiffness (relative order of magnitude among parameters) and, (3) the memoryless property assumes that events are independent and identically distributed.A model is always a compromise between faithfulness and simplicity. Results should be precise and correct (model predictions should be realistic and accurate based on a well founded mathematical theory, such as reliability theory). Model 1 Model 2 Model 3 Model 4 Fig. 1: Precise realistic models. ABSTRACTThe increasingly ubiquitous use of embedded systems to manage and control our technologically (ever-increasing) complex lives makes us more vulnerable than ever before. Knowing how reliable such systems are is absolutely necessary especially for safety, mission and infrastructure critical applications. This paper presents a structured compositional modeling method for assessing reliability based on characteristic data and stochastic models. We illustrate this using a classic embedded control system (sensor-inputs | processing | actuator-outputs), Anti-lock Braking System (ABS) and empirical data. Special emphasis is laid on modeling extra-functional characteristics of severity of failures, coincident failures and usage-profiles with the goal of developing a modeling strategy that is realistic, generic and extensible. The validation approach compares the results from the two separate models. The results are comparable and indicate the effect of coincident failures, failure severity and usage-profiles is predictable.

Probabilistic Optimization and Assessment of Voting Strategies for X-by-Wire Systems

“…Many approaches exist to evaluate dependability figures for distributed systems [7][8][9][10]. However, two main problems remain when dealing with above mentioned challenges:…”

Position Statement: Methodology to Support Dependable Survivable Cyber-Secure Infrastructures

“…The next generation of high performance dynamic and adaptive nonlinear networks, of which power systems are an application, will be designed and upgraded with interdisciplinary knowledge for achieving improved survivability, security, reliability, reconfigurability and efficiency 2 . Moreover, there is an urgent need for the development of innovative methods and conceptual frameworks for analysis, planning, and operation of complex, efficient, and secure electric power networks 3 .…”

“…The probability that the system-of-systems survives depends upon each of the constituent components and their interrelationships as well as system-of-systems relationships. Reliability analysis provides insight to developers about inherent (and defined) components and/or (intra-)system "weaknesses" [2][3][4][5]. Naturally, as the software/system complexity increase, the reliability analysis task becomes more difficult.…”