Simple and Efficient Batch Verification Techniques for Verifiable Delay Functions

2021 ◽  
pp. 382-414
Author(s):  
Lior Rotem
Author(s):  
Pierre-Loïc Garoche

The verification of control system software is critical to a host of technologies and industries, from aeronautics and medical technology to the cars we drive. The failure of controller software can cost people their lives. This book provides control engineers and computer scientists with an introduction to the formal techniques for analyzing and verifying this important class of software. Too often, control engineers are unaware of the issues surrounding the verification of software, while computer scientists tend to be unfamiliar with the specificities of controller software. The book provides a unified approach that is geared to graduate students in both fields, covering formal verification methods as well as the design and verification of controllers. It presents a wealth of new verification techniques for performing exhaustive analysis of controller software. These include new means to compute nonlinear invariants, the use of convex optimization tools, and methods for dealing with numerical imprecisions such as floating point computations occurring in the analyzed software. As the autonomy of critical systems continues to increase—as evidenced by autonomous cars, drones, and satellites and landers—the numerical functions in these systems are growing ever more advanced. The techniques presented here are essential to support the formal analysis of the controller software being used in these new and emerging technologies.


Dependability ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 3-12
Author(s):  
Yu. P. Pokhabov

Aim. To consider matters of dependability of highly critical non-recoverable space products with short operation life, whose failures are primarily caused by design and process engineering errors, manufacturing defects in the course of single-unit or small-scale production, as well as to define the methodological approach to ensuring the required reliability.Methods. Options were analysed for improving the dependability of entities with short operation life using the case study of single-use mechanical devices and the statistical approaches of the modern dependability theory, special methods of dependability of actuated mechanical assemblies, FMEA, Stage-Gate and ground experiments on single workout equivalents for each type of effect. Results. It was concluded that additional procedures need to be conducted for the purpose of predicting, mitigation and (or) eliminating possible failures as part of the design process using exactly the same approaches that cause failures, i.e., those of design and process engineering. The engineering approaches to dependability are based on early identification of possible causes of failures, which requires a qualified and systemic analysis aimed at identifying the functionality, performance and dependability of an entity, taking into account critical output parameters and probabilistic indicators that affect the performance of the required functions with the allowable probability of failure. The solution is found using a generalized parametric model of operation and design engineering analysis of dependability.Conclusion. For highly critical non-recoverable space entities with short operation life, the reliability requirements should be considered primarily in terms financial, economic, safetyrelated and reputational risks associated with the loss of spacecraft. From a design engineer’s standpoint, the number of nines after the decimal point (rounded to a smaller number of nines for increased confidence) should be seen as the indicator for the application of the appropriate approaches to ensuring the required reliability at the stage of product design. In case of two nines after the decimal point it is quite acceptable to use analytical and experimental verification techniques common to the aerospace industry, i.e., dependability calculations using the statistical methods of the modern dependability theory and performance indicators, FMEA and Stage-Gate, ground experiments on single workout equivalents for each type of effect. As the required number of nines grows, it is advisable to also use early failure prevention methods, one of which is the design engineering analysis of dependability that enables designers to adopt substantiated design solutions on the basis of engineering disciplines and design and process engineering methods of ensuring quality and dependability. The choice of either of the above dependability strategies is determined solely by the developer’s awareness and understanding of potential hazards, which allows managing the risk of potential rare failures or reasonably refusing to do so.


10.29007/7lrd ◽  
2018 ◽  
Author(s):  
Ian Cassar ◽  
Adrian Francalanza ◽  
Duncan Attard ◽  
Luca Aceto ◽  
Anna Ingolfsdottir

Ensuring formal correctness for actor-based, concurrent systems is a difficult task, pri- marily because exhaustive, static analysis verification techniques such as model checking quickly run into state-explosion problems. Runtime monitoring techniques such as Run- time Verification and Adaptation circumvent this limitation by verifying the correctness of a program by dynamically analysing its executions. This paper gives an overview of a suite of monitoring tools available for verifying and adapting actor-based Erlang programs.


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