This summer & autumn, our department is hosting Prof Magne Haveraaen (University Bergen, Norway)
As part of his involvement in ∆QSD group, he is organising a seminar talk:
Abstract.
Great progress has been made in assuring the functional correctness of digital systems. Coverage analysis, property-based testing, mock environments and formal proof systems can be applied to give very high levels of confidence of correct system behaviour. (That they are all too often not applied is a problem in social science, not computer science!). Despite this, many prototypes that demonstrate attractive functionality in a laboratory or test setting fail to deliver when deployed in the real world, often because non-functional aspects such as response time, efficiency, reliability or safety are unsatisfactory. These are typically not properly addressed until the system is largely implemented, when it may eventually become apparent that early design decisions were ill-advised, and changing them is expensive or even impossible.
As part of his involvement in ∆QSD group, he is organising a seminar talk:
“Assuring non-functional requirements”
Presented by Neil Davies (Bristol) and Peter Thompson (Predictable Network Solutions)
Friday, 4. 11, 14:00
CoFo 401
Abstract.
Great progress has been made in assuring the functional correctness of digital systems. Coverage analysis, property-based testing, mock environments and formal proof systems can be applied to give very high levels of confidence of correct system behaviour. (That they are all too often not applied is a problem in social science, not computer science!). Despite this, many prototypes that demonstrate attractive functionality in a laboratory or test setting fail to deliver when deployed in the real world, often because non-functional aspects such as response time, efficiency, reliability or safety are unsatisfactory. These are typically not properly addressed until the system is largely implemented, when it may eventually become apparent that early design decisions were ill-advised, and changing them is expensive or even impossible.
Our ongoing goal, a journey that we began over 20 years ago, is to quantify ‘non-functional’ requirements in such a way that they can be treated on an equal footing with functional ones at all stages of the development and deployment process. This abstracts the inherent stochastic variability of the real-world as a data type used in reasoning about timeliness and resource consumption. Such system properties can be calculated at any stage of system development, from early design considerations to deployed systems. In many critical situations, delivering a response within a given time-bound is as much a requirement as the correctness of the answer, as is doing so within the available resources. This approach also informs the way that system performance can be measured for effective in-life management and maintenance throughout the full system life cycle.
This seminar will provide an overview of our journey so far, how we are reasoning about timeliness and “failure” using a formalism (with prototype tool support) called ‘∆QSD’. We will provide examples of how this can inform “design intuition”; capture reliability; and act as a socialisation tool with stakeholders in a complex development.
References
Haeri, S.H.; Thompson, P.; Davies, N.; Van Roy, P.; Hammond, K.; Chapman, J. Mind Your Outcomes: The ∆QSD Paradigm for Quality-Centric Systems Development and Its Application to a Blockchain Case Study. Computers 2022,11,45. https://doi.org/10.3390/computers11030045
Seyed Hossein Haeri, Peter W. Thompson, Peter Van Roy, Magne Haveraaen, Neil J. Davies, Mikhail Barash, Kevin Hammond, James Chapman: Algebraic Reasoning About Timeliness. 16th Interaction and Concurrency Experience (ICE 2023) EPTCS 383, 2023, pp. 35–54, doi:10.4204/EPTCS.383.3
Presenters
Dr Neil Davies, BSc, PhD, MBCS, CEng, CITP
Neil Davies is an expert in resolving the practical and theoretical challenges of large scale distributed and high-performance computing, particularly scalability effects in large distributed systems, their operational quality, and how to manage their degradation gracefully under saturation and adverse operational conditions. He is a computer scientist,
mathematician and hands-on software developer who builds rigorously engineered working systems and scalable demonstrators of new computing and networking concepts.
Throughout his 20-year career at the University of Bristol he was involved with early developments in networking, its protocols and their implementations. He collaborated with organisations such as NATS, Nuclear Electric, HSE, ST Microelectronics and CERN on issues relating to scalable performance and operational safety. He was also technical lead on several large EU Framework collaborations relating to high performance switching, and has mentored PhD candidates at CERN.
Peter Thompson, BSc
Peter Thompson joined Predictable Network Solutions after several years as Chief Scientist of GoS Networks Limited (formerly U4EA Technologies). Previously he was co-founder and CEO of Degree2 Innovations, commercialising advanced research into network QoS undertaken with Neil Davies during the preceding four years at the Partnership in Advanced Computing Technology in Bristol, England, where he was a Senior Research Fellow.
Before that he spent eleven years at STMicroelectronics, where one of his numerous patents for parallel computing and communications received a corporate World-wide Technical Achievement Award. For five years he was the Subject Editor for VLSI and Architectures of the journal Microprocessors and Microsystems, published by Elsevier.
