630 research outputs found
Attack-Resilient Supervisory Control of Discrete-Event Systems
In this work, we study the problem of supervisory control of discrete-event
systems (DES) in the presence of attacks that tamper with inputs and outputs of
the plant. We consider a very general system setup as we focus on both
deterministic and nondeterministic plants that we model as finite state
transducers (FSTs); this also covers the conventional approach to modeling DES
as deterministic finite automata. Furthermore, we cover a wide class of attacks
that can nondeterministically add, remove, or rewrite a sensing and/or
actuation word to any word from predefined regular languages, and show how such
attacks can be modeled by nondeterministic FSTs; we also present how the use of
FSTs facilitates modeling realistic (and very complex) attacks, as well as
provides the foundation for design of attack-resilient supervisory controllers.
Specifically, we first consider the supervisory control problem for
deterministic plants with attacks (i) only on their sensors, (ii) only on their
actuators, and (iii) both on their sensors and actuators. For each case, we
develop new conditions for controllability in the presence of attacks, as well
as synthesizing algorithms to obtain FST-based description of such
attack-resilient supervisors. A derived resilient controller provides a set of
all safe control words that can keep the plant work desirably even in the
presence of corrupted observation and/or if the control words are subjected to
actuation attacks. Then, we extend the controllability theorems and the
supervisor synthesizing algorithms to nondeterministic plants that satisfy a
nonblocking condition. Finally, we illustrate applicability of our methodology
on several examples and numerical case-studies
Experiments with embedded system design at UMinho and AIT
Nowadays, embedded systems are central to modern life,
mainly due to the scientiļ¬c and technological advances of the last decades
that started a new reality in which the embedded systems market has
been growing steadily, along with a monthly or even weekly emergence
of new products with diļ¬erent applications across several domains. This
embedded system ubiquity was the drive for the following question āWhy
should we focus on embedded systems design?ā that was answered in [1,
2] with the following points: (1) high and fast penetration in products
and services due to the integration of networking, operating system and
database capabilities, (2) very strategic ļ¬eld economically and (3) a new
and relatively undeļ¬ned subject in academic environment. Other adja-
cent questions have been raised such as āWhy is the design of embedded
systems special?ā. The answer for this last question is based mainly on
several problems raised by the new technologies, such as the need for
more human resources in specialized areas and high learning curve for
system designers. As pointed in [1], these problems can prevent many
companies from adopting these new technologies or force them not to
respond timely in mastering these technological and market challenges.
In this paper, it is described how staļ¬ at ESRG-UMinho
1
and ISE-AIT
2
faced the embedded systems challenges at several levels. It starts to de-
scribe the development of the educational context for the new technolo-
gies and show how our Integrated Master Curriculum in Industrial Elec-
tronics and Computer Engineering has been adapted to satisfy the needs
of the major university customers, the industry
Constructivist Multi-Access Lab Approach in Teaching FPGA Systems Design with LabVIEW
Embedded systems play vital role in modern
applications [1]. They can be found in autos, washing
machines, electrical appliances and even in toys. FPGAs are
the most recent computing technology that is used in embedded
systems. There is an increasing demand on FPGA
based embedded systems, in particular, for applications that
require rapid time responses. Engineering education curricula
needs to respond to the increasing industrial demand of
using FPGAs by introducing new syllabus for teaching and
learning this subject. This paper describes the development
of new course material for teaching FPGA-based embedded
systems design by using āGā Programming Language of
LabVIEW. A general overview of FPGA role in engineering
education is provided. A survey of available Hardware
Programming Languages for FPGAs is presented. A survey
about LabVIEW utilization in engineering education is
investigated; this is followed by a motivation section of why
to use LabVIEW graphical programming in teaching and its
capabilities. Then, a section of choosing a suitable kit for the
course is laid down. Later, constructivist closed-loop model
the FPGA course has been proposed in accordance with [2-
4; 80,86,89,92]. The paper is proposing a pedagogical
framework for FPGA teaching; pedagogical evaluation will
be conducted in future studies. The complete study has been
done at the Faculty of Electrical and Electronic Engineering,
Aleppo University
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