3,510 research outputs found
Vocal Access to a Newspaper Archive: Design Issues and Preliminary Investigation
This paper presents the design and the current prototype implementation of an
interactive vocal Information Retrieval system that can be used to access
articles of a large newspaper archive using a telephone. The results of
preliminary investigation into the feasibility of such a system are also
presented
Towards a Formal Model of Privacy-Sensitive Dynamic Coalitions
The concept of dynamic coalitions (also virtual organizations) describes the
temporary interconnection of autonomous agents, who share information or
resources in order to achieve a common goal. Through modern technologies these
coalitions may form across company, organization and system borders. Therefor
questions of access control and security are of vital significance for the
architectures supporting these coalitions.
In this paper, we present our first steps to reach a formal framework for
modeling and verifying the design of privacy-sensitive dynamic coalition
infrastructures and their processes. In order to do so we extend existing
dynamic coalition modeling approaches with an access-control-concept, which
manages access to information through policies. Furthermore we regard the
processes underlying these coalitions and present first works in formalizing
these processes. As a result of the present paper we illustrate the usefulness
of the Abstract State Machine (ASM) method for this task. We demonstrate a
formal treatment of privacy-sensitive dynamic coalitions by two example ASMs
which model certain access control situations. A logical consideration of these
ASMs can lead to a better understanding and a verification of the ASMs
according to the aspired specification.Comment: In Proceedings FAVO 2011, arXiv:1204.579
On Modelling and Analysis of Dynamic Reconfiguration of Dependable Real-Time Systems
This paper motivates the need for a formalism for the modelling and analysis
of dynamic reconfiguration of dependable real-time systems. We present
requirements that the formalism must meet, and use these to evaluate well
established formalisms and two process algebras that we have been developing,
namely, Webpi and CCSdp. A simple case study is developed to illustrate the
modelling power of these two formalisms. The paper shows how Webpi and CCSdp
represent a significant step forward in modelling adaptive and dependable
real-time systems.Comment: Presented and published at DEPEND 201
The 14th Overture Workshop: Towards Analytical Tool Chains
This report contains the proceedings from the 14th Overture workshop organized in connection with the Formal Methods 2016 symposium. This includes nine papers describing different technological progress in relation to the Overture/VDM tool support and its connection with other tools such as Crescendo, Symphony, INTO-CPS, TASTE and ViennaTalk
Enhancing System Realisation in Formal Model Development
Software for mission-critical systems is sometimes analysed using formal specification to increase the chances of the system behaving as intended. When sufficient insights into the system have been obtained from the formal analysis, the formal specification is realised in the form of a software implementation. One way to realise the system's software is by automatically generating it from the formal specification -- a technique referred to as code generation. However, in general it is difficult to make guarantees about the correctness of the generated code -- especially while requiring automation of the steps involved in realising the formal specification. This PhD dissertation investigates ways to improve the automation of the steps involved in realising and validating a system based on a formal specification. The approach aims to develop properly designed software tools which support the integration of formal methods tools into the software development life cycle, and which leverage the formal specification in the subsequent validation of the system. The tools developed use a new code generation infrastructure that has been built as part of this PhD project and implemented in the Overture tool -- a formal methods tool that supports the Vienna Development Method. The development of the code generation infrastructure has involved the re-design of the software architecture of Overture. The new architecture brings forth the reuse and extensibility features of Overture to take into account the needs and requirements of software extensions targeting Overture. The tools developed in this PhD project have successfully supported three case studies from externally funded projects. The feedback received from the case study work has further helped improve the code generation infrastructure and the tools built using it
Measuring cluster peculiar velocities with the Sunyaev-Zeldovich effects: scaling relations and systematics
The fluctuations in the Cosmic Microwave Background (CMB) intensity due to
the Sunyaev-Zeldovich (SZ) effect are the sum of a thermal and a kinetic
contribution. Separating the two components to measure the peculiar velocity of
galaxy clusters requires radio and microwave observations at three or more
frequencies, and knowledge of the temperature T_e of the intracluster medium
weighted by the electron number density. To quantify the systematics of this
procedure, we extract a sample of 117 massive clusters at redshift z=0 from an
N-body hydrodynamical simulation, with 2x480^3 particles, of a cosmological
volume 192 Mpc/h on a side of a flat Cold Dark Matter model with Omega_0=0.3
and Lambda=0.7. Our simulation includes radiative cooling, star formation and
the effect of feedback and galactic winds from supernovae. We find that (1) our
simulated clusters reproduce the observed scaling relations between X-ray and
SZ properties; (2) bulk flows internal to the intracluster medium affect the
velocity estimate by less than 200 km/s in 93 per cent of the cases; (3) using
the X-ray emission weighted temperature, as an estimate of T_e, can
overestimate the peculiar velocity by 20-50 per cent, if the microwave
observations do not spatially resolve the cluster. For spatially resolved
clusters, the assumptions on the spatial distribution of the ICM, required to
separate the two SZ components, still produce a velocity overestimate of 10-20
per cent, even with an unbiased measure of T_e. Thanks to the large size of our
cluster samples, these results set a robust lower limit of 200 km/s to the
systematic errors that will affect upcoming measures of cluster peculiar
velocities with the SZ effect.Comment: 14 pages, 12 figures, MNRAS, in press. Figures 3 and 4 now contain
more recent observational data. Other minor revisions according to referee's
comment
System-Level Energy-Aware Design of Cyber-Physical Systems
In this technical report we present the work conducted during the first part of the PhD thesis “System-Level Energy-Aware Design of Cyber-Physical Systems”. We present the application of modelling techniques and methodologies to study energy consumption during the design and implementation of cyber-physical systems. This study is made from the electro-mechanical and computation angle. Additionally we present a setup that allows the combination of abstract models with hardware and software preliminary realizations. This allows a stepwise model to implementation transformation and improved model accuracy. Some of these techniques have been applied to the case study e-Stocking and others have been studied with more simple experimental setups.In addition to the scientific content, we also present a description of the envisioned future work and the plans that will lead to completion of this PhD thesis by April 2015
Proceedings of the 11th Overture Workshop
The 11th Overture Workshop was held in Aarhus, Denmark on Wed/Thu 28–29th Au- gust 2013. It was the 11th workshop in the current series focusing on the Vienna De- velopment Method (VDM) and particularly its community-based tools development project, Overture (http://www.overturetool.org/), and related projects such as COMPASS(http://www.compass-research.eu/) and DESTECS (http://www.destecs.org). Invited talks were given by Yves Ledru and Joe Kiniry. The workshop attracted 25 participants representing 10 nationalities. The goal of the workshop was to provide a forum to present new ideas, to identify and encourage new collaborative research, and to foster current strands of work towards publication in the mainstream conferences and journals. The Overture initiative held its first workshop at FM’05. Workshops were held subsequently at FM’06, FM’08 and FM’09, FM’11, FM’12 and in between
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