92 research outputs found
LIPIcs, Volume 274, ESA 2023, Complete Volume
LIPIcs, Volume 274, ESA 2023, Complete Volum
A Unified Model for Real-Time Systems: Symbolic Techniques and Implementation
In this paper, we consider a model of generalized timed automata (GTA) with
two kinds of clocks, history and future, that can express many timed features
succinctly, including timed automata, event-clock automata with and without
diagonal constraints, and automata with timers.
Our main contribution is a new simulation-based zone algorithm for checking
reachability in this unified model. While such algorithms are known to exist
for timed automata, and have recently been shown for event-clock automata
without diagonal constraints, this is the first result that can handle
event-clock automata with diagonal constraints and automata with timers. We
also provide a prototype implementation for our model and show experimental
results on several benchmarks. To the best of our knowledge, this is the first
effective implementation not just for our unified model, but even just for
automata with timers or for event-clock automata (with predicting clocks)
without going through a costly translation via timed automata. Last but not
least, beyond being interesting in their own right, generalized timed automata
can be used for model-checking event-clock specifications over timed automata
models
2022-2023 Graduate School Catalog
Graduate students from more than 67 counties are providing outstanding leadership during the pandemic, as they conduct vital research to inform public health, contribute to the greater good, and stimulate the economy. Their scholarship spans 140 programs - from biomedical engineering to business administration, from history to horticulture, and from marine sciences to music performance
Trajectory planning based on adaptive model predictive control: Study of the performance of an autonomous vehicle in critical highway scenarios
Increasing automation in automotive industry is an important contribution to
overcome many of the major societal challenges. However, testing and validating a highly
autonomous vehicle is one of the biggest obstacles to the deployment of such vehicles,
since they rely on data-driven and real-time sensors, actuators, complex algorithms,
machine learning systems, and powerful processors to execute software, and they must
be proven to be reliable and safe.
For this reason, the verification, validation and testing (VVT) of autonomous
vehicles is gaining interest and attention among the scientific community and there has
been a number of significant efforts in this field. VVT helps developers and testers to
determine any hidden faults, increasing systems confidence in safety, security, functional
analysis, and in the ability to integrate autonomous prototypes into existing road
networks. Other stakeholders like higher-management, public authorities and the public
are also crucial to complete the VTT process.
As autonomous vehicles require hundreds of millions of kilometers of testing
driven on public roads before vehicle certification, simulations are playing a key role as
they allow the simulation tools to virtually test millions of real-life scenarios, increasing
safety and reducing costs, time and the need for physical road tests.
In this study, a literature review is conducted to classify approaches for the VVT
and an existing simulation tool is used to implement an autonomous driving system. The
system will be characterized from the point of view of its performance in some critical
highway scenarios.O aumento da automação na indústria automotiva é uma importante
contribuição para superar muitos dos principais desafios da sociedade. No entanto,
testar e validar um veÃculo altamente autónomo é um dos maiores obstáculos para a
implantação de tais veÃculos, uma vez que eles contam com sensores, atuadores,
algoritmos complexos, sistemas de aprendizagem de máquina e processadores potentes
para executar softwares em tempo real, e devem ser comprovadamente confiáveis e
seguros.
Por esta razão, a verificação, validação e teste (VVT) de veÃculos autónomos está
a ganhar interesse e atenção entre a comunidade cientÃfica e tem havido uma série de
esforços significativos neste campo. A VVT ajuda os desenvolvedores e testadores a
determinar quaisquer falhas ocultas, aumentando a confiança dos sistemas na
segurança, proteção, análise funcional e na capacidade de integrar protótipos autónomos
em redes rodoviárias existentes. Outras partes interessadas, como a alta administração,
autoridades públicas e o público também são cruciais para concluir o processo de VTT.
Como os veÃculos autónomos exigem centenas de milhões de quilómetros de
testes conduzidos em vias públicas antes da certificação do veÃculo, as simulações estão
a desempenhar cada vez mais um papel fundamental, pois permitem que as ferramentas
de simulação testem virtualmente milhões de cenários da vida real, aumentando a
segurança e reduzindo custos, tempo e necessidade de testes fÃsicos em estrada.
Neste estudo, é realizada uma revisão da literatura para classificar abordagens
para a VVT e uma ferramenta de simulação existente é usada para implementar um
sistema de direção autónoma. O sistema é caracterizado do ponto de vista do seu
desempenho em alguns cenários crÃticos de autoestrad
Applying the Free-Energy Principle to Complex Adaptive Systems
The free energy principle is a mathematical theory of the behaviour of self-organising systems that originally gained prominence as a unified model of the brain. Since then, the theory has been applied to a plethora of biological phenomena, extending from single-celled and multicellular organisms through to niche construction and human culture, and even the emergence of life itself. The free energy principle tells us that perception and action operate synergistically to minimize an organism’s exposure to surprising biological states, which are more likely to lead to decay. A key corollary of this hypothesis is active inference—the idea that all behavior involves the selective sampling of sensory data so that we experience what we expect to (in order to avoid surprises). Simply put, we act upon the world to fulfill our expectations. It is now widely recognized that the implications of the free energy principle for our understanding of the human mind and behavior are far-reaching and profound. To date, however, its capacity to extend beyond our brain—to more generally explain living and other complex adaptive systems—has only just begun to be explored. The aim of this collection is to showcase the breadth of the free energy principle as a unified theory of complex adaptive systems—conscious, social, living, or not
Simulations for Event-Clock Automata
Event-clock automata are a well-known subclass of timed automata which enjoy admirable theoretical properties, e.g., determinizability, and are practically useful to capture timed specifications. However, unlike for timed automata, there exist no implementations for event-clock automata. A main reason for this is the difficulty in adapting zone-based algorithms, critical in the timed automata setting, to the event-clock automata setting. This difficulty was studied in [Gilles Geeraerts et al., 2011; Gilles Geeraerts et al., 2014], where the authors also proposed a solution using zone extrapolations.
In this paper, we propose an alternative zone-based algorithm, using simulations for finiteness, to solve the reachability problem for event-clock automata. Our algorithm exploits the ?-simulation framework, which is the coarsest known simulation relation for reachability, and has been recently used for advances in other extensions of timed automata
Zone-based verification of timed automata: extrapolations, simulations and what next?
Timed automata have been introduced by Rajeev Alur and David Dill in the
early 90's. In the last decades, timed automata have become the de facto model
for the verification of real-time systems. Algorithms for timed automata are
based on the traversal of their state-space using zones as a symbolic
representation. Since the state-space is infinite, termination relies on finite
abstractions that yield a finite representation of the reachable states.
The first solution to get finite abstractions was based on extrapolations of
zones, and has been implemented in the industry-strength tool Uppaal. A
different approach based on simulations between zones has emerged in the last
ten years, and has been implemented in the fully open source tool TChecker. The
simulation-based approach has led to new efficient algorithms for reachability
and liveness in timed automata, and has also been extended to richer models
like weighted timed automata, and timed automata with diagonal constraints and
updates.
In this article, we survey the extrapolation and simulation techniques, and
discuss some open challenges for the future.Comment: Invited contribution at FORMATS'2
Collusion-Resistant Functional Encryption for RAMs
In recent years, functional encryption (FE) has established itself as one of the fundamental primitives in cryptography. The choice of model of computation to represent the functions associated with the functional keys plays a critical role in the complexity of the algorithms of an FE scheme. Historically, the functions are represented as circuits. However, this results in the decryption time of the FE scheme growing proportional to not only the worst case running time of the function but also the size of the input, which in many applications can be quite large.
In this work, we present the first construction of a public-key collusion-resistant FE scheme, where the functions, associated with the keys, are represented as random access machines (RAMs). We base the security of our construction on the existence of: (i) public-key collusion- resistant FE for circuits and, (ii) public-key doubly-efficient private-information retrieval [Boyle et al., Canetti et al., TCC 2017]. Our scheme enjoys many nice efficiency properties, including input-specific decryption time.
We also show how to achieve FE for RAMs in the bounded-key setting with weaker efficiency guarantees from laconic oblivious transfer, which can be based on standard cryptographic assumptions. En route to achieving our result, we present conceptually simpler constructions of succinct garbling for RAMs [Canetti et al., Chen et al., ITCS 2016] from weaker assumptions
Computer Aided Verification
This open access two-volume set LNCS 11561 and 11562 constitutes the refereed proceedings of the 31st International Conference on Computer Aided Verification, CAV 2019, held in New York City, USA, in July 2019. The 52 full papers presented together with 13 tool papers and 2 case studies, were carefully reviewed and selected from 258 submissions. The papers were organized in the following topical sections: Part I: automata and timed systems; security and hyperproperties; synthesis; model checking; cyber-physical systems and machine learning; probabilistic systems, runtime techniques; dynamical, hybrid, and reactive systems; Part II: logics, decision procedures; and solvers; numerical programs; verification; distributed systems and networks; verification and invariants; and concurrency
- …