Antonio Anastasio Bruto da Costa

• Doctor of Philosophy
• Research Fellow at University of Warwick

The verification and validation (V&V) process for Automated Driving Systems (ADS) has undergone a significant transformation in defining the meaning of safety. Initially rooted in the quantity of miles driven, it has now shifted towards emphasizing the quality of test miles. These test miles must effectively capture the full spectrum of behaviours...

Engineering knowledge-based (or expert) systems require extensive manual effort and domain knowledge. As Large Language Models (LLMs) are trained using an enormous amount of cross-domain knowledge, it becomes possible to automate such engineering processes. This paper presents an empirical automation and semi-automation framework for domain knowled...

Multi-party dialogues are common in enterprise social media on technical as well as non-technical topics. The outcome of a conversation may be positive or negative. It is important to analyze why a dialogue ends with a particular sentiment from the point of view of conflict analysis as well as future collaboration design. We propose an explainable...

We aim to mine temporal causal sequences that explain observed events (consequents) in time-series traces. Causal explanations of key events in a time-series have applications in design debugging, anomaly detection, planning, root-cause analysis and many more. We make use of decision trees and interval arithmetic to mine sequences that explain defi...

The analysis and verification of hybrid automata (HA) models against rich formal properties can be a challenging task. Existing methods and tools can mainly reason whether a given property is satisfied or violated. However, such qualitative answers might not provide sufficient information about the model behaviors. This paper presents the ForFET$^{...

The notion of recurrence over continuous or dense time, as required for expressing analog and mixed-signal behaviors, is fundamentally different from what is offered by the recurrence operators of SystemVerilog assertions (SVAs). This article introduces the formal semantics of recurrence over dense time and provides a methodology for the runtime...

The notion of recurrence over continuous or dense time, as required for expressing Analog and Mixed-Signal (AMS) behaviours, is fundamentally different from what is offered by the recurrence operators of SystemVerilog Assertions (SVA). This article introduces the formal semantics of recurrence over dense time and provides a methodology for the runt...

A large fraction of bugs discovered in the design flow of Embedded Control Software (ECS) embedded control software arises from the control software’s interaction with the plant it controls. Traditional formal analysis approaches using interleaved controller-plant reach-set analysis grossly over-approximate the reachable states and does not scale....

Mining temporal assertions from time-series data using information theory to filter real properties from incidental ones is a practically significant challenge. The problem is complex for continuous or hybrid systems because the degrees of influence on a consequent from a timed-sequence of predicates (called its prefix sequence), varies continuousl...

In current practice a formal analysis of hybrid system models is assertion-based. The work presented here is based on features that look beyond functional correctness toward a quantitative evaluation of behavioral attributes. A feature defines a real-valued evaluation function over a specific set of traces. This paper describes an improved method...

The ability to produce music is perhaps the most endearing quality in human beings. The sounds of music all over the world stand united on the 12 notes in an octave. While the physics of music and the incredible ability of human beings to perceive and reproduce notes and rhythm has been the subject of significant research spanning centuries, Indian...

Model based design is a recommended step in the design of embedded control systems. A formal analysis of models helps in arriving at provably correct designs that meet the necessary functional requirements. Often such analysis needs to look beyond functional correctness to evaluate the margins of behavioral attributes. Our notion of features addres...

This tool paper discusses the design and implementation of the formal feature evaluation tool for hybrid systems, ForFET. Features extend the notion of assertions by associating a computable function to the match of an assertion. This paper illustrates the practical utility of feature evaluation through several examples.

The acceptance criteria for analog designs are traditionally defined in terms of real-valued features defined over behavioral responses. For example, rise time, peak overshoot, and settling time are features of the response of a second-order system under a step input. Designers of analog and mixed-signal (AMS) designs typically like to see whether...

The paper proposes the adoption of formal methods for modeling of analog functions. It explains how assertions can be overlaid onto the range of values of individual features in an analog function, and proceeds toward building a mathematical (hybrid automata) model to represent and analyze them. An LDO regulator and a battery charger are used as ex...