86,080 research outputs found
Conceptual modelling: Towards detecting modelling errors in engineering applications
Rapid advancements of modern technologies put high demands on mathematical modelling of engineering systems. Typically, systems are no longer āsimpleā objects, but rather coupled systems involving multiphysics phenomena, the modelling of which involves coupling of models that describe different phenomena. After constructing a mathematical model, it is essential to analyse the correctness of the coupled models and to detect modelling errors compromising the final modelling result. Broadly, there are two classes of modelling errors: (a) errors related to abstract modelling, eg, conceptual errors concerning the coherence of a model as a whole and (b) errors related to concrete modelling or instance modelling, eg, questions of approximation quality and implementation. Instance modelling errors, on the one hand, are relatively well understood. Abstract modelling errors, on the other, are not appropriately addressed by modern modelling methodologies. The aim of this paper is to initiate a discussion on abstract approaches and their usability for mathematical modelling of engineering systems with the goal of making it possible to catch conceptual modelling errors early and automatically by computer assistant tools. To that end, we argue that it is necessary to identify and employ suitable mathematical abstractions to capture an accurate conceptual description of the process of modelling engineering systems
Virtual Communication Stack: Towards Building Integrated Simulator of Mobile Ad Hoc Network-based Infrastructure for Disaster Response Scenarios
Responses to disastrous events are a challenging problem, because of possible
damages on communication infrastructures. For instance, after a natural
disaster, infrastructures might be entirely destroyed. Different network
paradigms were proposed in the literature in order to deploy adhoc network, and
allow dealing with the lack of communications. However, all these solutions
focus only on the performance of the network itself, without taking into
account the specificities and heterogeneity of the components which use it.
This comes from the difficulty to integrate models with different levels of
abstraction. Consequently, verification and validation of adhoc protocols
cannot guarantee that the different systems will work as expected in
operational conditions. However, the DEVS theory provides some mechanisms to
allow integration of models with different natures. This paper proposes an
integrated simulation architecture based on DEVS which improves the accuracy of
ad hoc infrastructure simulators in the case of disaster response scenarios.Comment: Preprint. Unpublishe
Towards Autopoietic Computing
A key challenge in modern computing is to develop systems that address
complex, dynamic problems in a scalable and efficient way, because the
increasing complexity of software makes designing and maintaining efficient and
flexible systems increasingly difficult. Biological systems are thought to
possess robust, scalable processing paradigms that can automatically manage
complex, dynamic problem spaces, possessing several properties that may be
useful in computer systems. The biological properties of self-organisation,
self-replication, self-management, and scalability are addressed in an
interesting way by autopoiesis, a descriptive theory of the cell founded on the
concept of a system's circular organisation to define its boundary with its
environment. In this paper, therefore, we review the main concepts of
autopoiesis and then discuss how they could be related to fundamental concepts
and theories of computation. The paper is conceptual in nature and the emphasis
is on the review of other people's work in this area as part of a longer-term
strategy to develop a formal theory of autopoietic computing.Comment: 10 Pages, 3 figure
ISML: an interface specification meta-language
In this paper we present an abstract metaphor model situated within a model-based user interface framework. The inclusion of metaphors in graphical user interfaces is a well established, but mostly craft-based strategy to design. A substantial body of notations and tools can be found within the model-based user interface design literature, however an explicit treatment of metaphor and its mappings to other design views has yet to be addressed. We introduce the Interface Specification Meta-Language (ISML) framework and demonstrate its use in comparing the semantic and syntactic features of an interactive system. Challenges facing this research are outlined and further work proposed
Reclaiming human machine nature
Extending and modifying his domain of life by artifact production is one of
the main characteristics of humankind. From the first hominid, who used a wood
stick or a stone for extending his upper limbs and augmenting his gesture
strength, to current systems engineers who used technologies for augmenting
human cognition, perception and action, extending human body capabilities
remains a big issue. From more than fifty years cybernetics, computer and
cognitive sciences have imposed only one reductionist model of human machine
systems: cognitive systems. Inspired by philosophy, behaviorist psychology and
the information treatment metaphor, the cognitive system paradigm requires a
function view and a functional analysis in human systems design process.
According that design approach, human have been reduced to his metaphysical and
functional properties in a new dualism. Human body requirements have been left
to physical ergonomics or "physiology". With multidisciplinary convergence, the
issues of "human-machine" systems and "human artifacts" evolve. The loss of
biological and social boundaries between human organisms and interactive and
informational physical artifact questions the current engineering methods and
ergonomic design of cognitive systems. New developpment of human machine
systems for intensive care, human space activities or bio-engineering sytems
requires grounding human systems design on a renewed epistemological framework
for future human systems model and evidence based "bio-engineering". In that
context, reclaiming human factors, augmented human and human machine nature is
a necessityComment: Published in HCI International 2014, Heraklion : Greece (2014
Hamiltonian Formulation of Quantum Error Correction and Correlated Noise: The Effects Of Syndrome Extraction in the Long Time Limit
We analyze the long time behavior of a quantum computer running a quantum
error correction (QEC) code in the presence of a correlated environment.
Starting from a Hamiltonian formulation of realistic noise models, and assuming
that QEC is indeed possible, we find formal expressions for the probability of
a faulty path and the residual decoherence encoded in the reduced density
matrix. Systems with non-zero gate times (``long gates'') are included in our
analysis by using an upper bound on the noise. In order to introduce the local
error probability for a qubit, we assume that propagation of signals through
the environment is slower than the QEC period (hypercube assumption). This
allows an explicit calculation in the case of a generalized spin-boson model
and a quantum frustration model. The key result is a dimensional criterion: If
the correlations decay sufficiently fast, the system evolves toward a
stochastic error model for which the threshold theorem of fault-tolerant
quantum computation has been proven. On the other hand, if the correlations
decay slowly, the traditional proof of this threshold theorem does not hold.
This dimensional criterion bears many similarities to criteria that occur in
the theory of quantum phase transitions.Comment: 19 pages, 5 figures. Includes response to arXiv:quant-ph/0702050. New
title and an additional exampl
Affordances and Safe Design of Assistance Wearable Virtual Environment of Gesture
Safety and reliability are the main issues for designing assistance wearable
virtual environment of technical gesture in aerospace, or health application
domains. That needs the integration in the same isomorphic engineering
framework of human requirements, systems requirements and the rationale of
their relation to the natural and artifactual environment.To explore coupling
integration and design functional organization of support technical gesture
systems, firstly ecological psychologyprovides usa heuristicconcept: the
affordance. On the other hand mathematical theory of integrative physiology
provides us scientific concepts: the stabilizing auto-association principle and
functional interaction.After demonstrating the epistemological consistence of
these concepts, we define an isomorphic framework to describe and model human
systems integration dedicated to human in-the-loop system engineering.We
present an experimental approach of safe design of assistance wearable virtual
environment of gesture based in laboratory and parabolic flights. On the
results, we discuss the relevance of our conceptual approach and the
applications to future assistance of gesture wearable systems engineering
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