1,516,928 research outputs found
Model Driven Development of m-Health Systems (with a Touch of Formality)
We propose a model driven design and development methodology augmented with formal validation and verification (V&V) for the development of mobile health systems. Systems which deliver healthcare services remotely should be developed using robust and trusted engineering technologies. The methodology instantiates steps in the MDA trajectory using formal methods to verify critical properties of models, to test preservation of those properties in the derived implementations and to effect model transformations by correctness preserving transformations. The methodology is described and some initial modelling is reported
Analysis of multi-degree-of-freedom nonlinear systems using nonlinear output frequency response functions
The analysis of multi-degree-of-freedom (MDOF) nonlinear systems is studied using the concept of Nonlinear Output Frequency Response Functions (NOFRFs). The results reveal very important properties of MDOF systems, which are of significant importance for the analysis of nonlinear structures. One important application of the results obtained in this study is the detection and location of faults in engineering structures which make the structures behave nonlinearly
Using effective medium theories to design tailored nanocomposite materials for optical systems
Modern optical systems are subject to very restrictive performance, size and
cost requirements. Especially in portable systems size often is the most
important factor, which necessitates elaborate designs to achieve the desired
specifications. However, current designs already operate very close to the
physical limits and further progress is difficult to achieve by changing only
the complexity of the design. Another way of improving the performance is to
tailor the optical properties of materials specifically to the application at
hand. A class of novel, customizable materials that enables the tailoring of
the optical properties, and promises to overcome many of the intrinsic
disadvantages of polymers, are nanocomposites. However, despite considerable
past research efforts, these types of materials are largely underutilized in
optical systems. To shed light into this issue we, in this paper, discuss how
nanocomposites can be modeled using effective medium theories. In the second
part, we then investigate the fundamental requirements that have to be
fulfilled to make nanocomposites suitable for optical applications, and show
that it is indeed possible to fabricate such a material using existing methods.
Furthermore, we show how nanocomposites can be used to tailor the refractive
index and dispersion properties towards specific applications.Comment: This is a draft manuscript of a paper published in Proc. SPIE
(Proceedings Volume 10745, Current Developments in Lens Design and Optical
Engineering XIX, Event: SPIE Optical Engineering + Applications, 2018
Fine Grained Component Engineering of Adaptive Overlays: Experiences and Perspectives
Recent years have seen significant research being carried out into peer-to-peer (P2P) systems. This work has focused on the styles and applications of P2P computing, from grid computation to content distribution; however, little investigation has been performed into how these systems are built. Component based engineering is an approach that has seen successful deployment in the field of middleware development; functionality is encapsulated in âbuilding blocksâ that can be dynamically plugged together to form complete systems. This allows efficient, flexible and adaptable systems to be built with lower overhead and development complexity. This paper presents an investigation into the potential of using component based engineering in the design and construction of peer-to-peer overlays. It is highlighted that the quality of these properties is dictated by the component architecture used to implement the system. Three reusable decomposition architectures are designed and evaluated using Chord and Pastry case studies. These demonstrate that significant improvements can be made over traditional design approaches resulting in much more reusable, (re)configurable and extensible systems
Verifying Temporal Properties of Reactive Systems by Transformation
We show how program transformation techniques can be used for the
verification of both safety and liveness properties of reactive systems. In
particular, we show how the program transformation technique distillation can
be used to transform reactive systems specified in a functional language into a
simplified form that can subsequently be analysed to verify temporal properties
of the systems. Example systems which are intended to model mutual exclusion
are analysed using these techniques with respect to both safety (mutual
exclusion) and liveness (non-starvation), with the errors they contain being
correctly identified.Comment: In Proceedings VPT 2015, arXiv:1512.02215. This work was supported,
in part, by Science Foundation Ireland grant 10/CE/I1855 to Lero - the Irish
Software Engineering Research Centre (www.lero.ie), and by the School of
Computing, Dublin City Universit
Using of aerogel to improve thermal insulating properties of windows
For the best possible thermal-technical properties of building structures it is necessary to use materials with very low thermal conductivity. Due to the increasing thermal-technical requirements for building structures, the insulating materials are developed. One of the modern thermal insulating materials is so-called aerogel. Unfortunately, this material is not used in the field of external thermal insulation composite systems because of its price and its properties. The aim of this paper is to present possibilities of using this insulating material in the civil engineering - specifically a usage of aerogel in the production of windows.Web of Science14111
On the Modular Specification of NFPs: A Case Study
The modular specification of non-functional properties of systems is a current challenge of Software Engineering, for which no clear solution exists. However, in the case of Domain-Specific Languages some successful proposals are starting to emerge, combining model-driven techniques with aspect-weaving mechanisms. In this paper we show one of these approaches in practice, and present the implementation we have developed to fully support it. We apply our approach for the specification and monitoring of non-functional properties using observers to a case study, illustrating how generic observers defining non-functional properties can be defined in an independent manner. Then, correspondences between these observers and the domain-specific model of the system can be established, and then weaved into a unified system specification using ATL model transformation. Such a unified specification can also be analyzed in a natural way to obtain the required non-functional properties of the system.This work is partially funded by Research Projects TIN2011-23795 and TIN2011-15497-E
Bisimulation, Logic and Reachability Analysis for Markovian Systems
In the recent years, there have been a large amount of investigations on safety verification of uncertain continuous systems. In engineering and applied mathematics, this verification is called stochastic reachability analysis, while in computer science this is called probabilistic model checking
(PMC). In the context of this work, we consider the two terms interchangeable. It is worthy to note that PMC has been mostly considered for discrete systems. Therefore, there is an issue of improving the application of computer science techniques in the formal verification of continuous stochastic systems.
We present a new probabilistic logic of model theoretic nature. The terms of this logic express reachability properties and the logic formulas express statistical properties of terms.
Moreover, we show that this logic characterizes a bisimulation relation for continuous time continuous space Markov processes. For this logic we define a new semantics using state space symmetries. This is a recent concept that was successfully used in model checking. Using this semantics, we prove a full abstraction result. Furthermore, we prove a result that can be used in model checking, namely that the bisimulation preserves the probabilities of the reachable sets
Crystal engineering using functionalized adamantane
We performed a first principles investigation on the structural, electronic,
and optical properties of crystals made of chemically functionalized adamantane
molecules. Several molecular building blocks, formed by boron and nitrogen
substitutional functionalizations, were considered to build zincblende and
wurtzite crystals, and the resulting structures presented large bulk moduli and
cohesive energies, wide and direct bandgaps, and low dielectric constants
(low- materials). Those properties provide stability for such
structures up to room temperature, superior to those of typical molecular
crystals. This indicates a possible road map for crystal engineering using
functionalized diamondoids, with potential applications ranging from space
filling between conducting wires in nanodevices to nano-electro-mechanical
systems
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