49,125 research outputs found
Towards a Layered Architectural View for Security Analysis in SCADA Systems
Supervisory Control and Data Acquisition (SCADA) systems support and control
the operation of many critical infrastructures that our society depend on, such
as power grids. Since SCADA systems become a target for cyber attacks and the
potential impact of a successful attack could lead to disastrous consequences
in the physical world, ensuring the security of these systems is of vital
importance. A fundamental prerequisite to securing a SCADA system is a clear
understanding and a consistent view of its architecture. However, because of
the complexity and scale of SCADA systems, this is challenging to acquire. In
this paper, we propose a layered architectural view for SCADA systems, which
aims at building a common ground among stakeholders and supporting the
implementation of security analysis. In order to manage the complexity and
scale, we define four interrelated architectural layers, and uses the concept
of viewpoints to focus on a subset of the system. We indicate the applicability
of our approach in the context of SCADA system security analysis.Comment: 7 pages, 4 figure
A semantic-based platform for the digital analysis of architectural heritage
This essay focuses on the fields of architectural documentation and digital representation. We present a research paper concerning the development of an information system at the scale of architecture, taking into account the relationships that can be established between the representation of buildings (shape, dimension, state of conservation, hypothetical restitution) and heterogeneous information about various fields (such as the technical, the documentary or still the historical one). The proposed approach aims to organize multiple representations (and associated information) around a semantic description model with the goal of defining a system for the multi-field analysis of buildings
Towards a Holistic CAD Platform for Nanotechnologies
Silicon-based CMOS technologies are predicted to reach their ultimate limits
by the middle of the next decade. Research on nanotechnologies is actively
conducted, in a world-wide effort to develop new technologies able to maintain
the Moore's law. They promise revolutionizing the computing systems by
integrating tremendous numbers of devices at low cost. These trends will have a
profound impact on the architectures of computing systems and will require a
new paradigm of CAD. The paper presents a work in progress on this direction.
It is aimed at fitting requirements and constraints of nanotechnologies, in an
effort to achieve efficient use of the huge computing power promised by them.
To achieve this goal we are developing CAD tools able to exploit efficiently
these huge computing capabilities promised by nanotechnologies in the domain of
simulation of complex systems composed by huge numbers of relatively simple
elements.Comment: Submitted on behalf of TIMA Editions
(http://irevues.inist.fr/tima-editions
Advances in the Hierarchical Emergent Behaviors (HEB) approach to autonomous vehicles
Widespread deployment of autonomous vehicles (AVs) presents formidable challenges in terms on handling scalability and complexity, particularly regarding vehicular reaction in the face of unforeseen corner cases. Hierarchical Emergent Behaviors (HEB) is a scalable architecture based on the concepts of emergent behaviors and hierarchical decomposition. It relies on a few simple but powerful rules to govern local vehicular interactions. Rather than requiring prescriptive programming of every possible scenario, HEB’s approach relies on global behaviors induced by the application of these local, well-understood rules. Our first two papers on HEB focused on a primal set of rules applied at the first hierarchical level. On the path to systematize a solid design methodology, this paper proposes additional rules for the second level, studies through simulations the resultant richer set of emergent behaviors, and discusses the communica-tion mechanisms between the different levels.Peer ReviewedPostprint (author's final draft
Analysis of source code metrics from ns-2 and ns-3 network simulators
Ns-2 and its successor ns-3 are discrete-event simulators which are closely related to each
other as they share common background, concepts and similar aims. Ns-3 is still under
development, but it offers some interesting characteristics for developers while ns-2 still
has a large user base. While other studies have compared different network simulators,
focusing on performance measurements, in this paper we adopted a different approach
by focusing on technical characteristics and using software metrics to obtain useful conclusions.
We chose ns-2 and ns-3 for our case study because of the popularity of the former in
research and the increasing use of the latter. This reflects the current situation where ns-3
has emerged as a viable alternative to ns-2 due to its features and design. The paper
assesses the current state of both projects and their respective evolution supported by
the measurements obtained from a broad set of software metrics. By considering other
qualitative characteristics we obtained a summary of technical features of both simulators
including, architectural design, software dependencies or documentation policies.Ministerio de Ciencia e Innovación TEC2009-10639-C04-0
Process of designing robust, dependable, safe and secure software for medical devices: Point of care testing device as a case study
This article has been made available through the Brunel Open Access Publishing Fund.Copyright © 2013 Sivanesan Tulasidas et al. This paper presents a holistic methodology for the design of medical device software, which encompasses of a new way of eliciting requirements, system design process, security design guideline, cloud architecture design, combinatorial testing process and agile project management. The paper uses point of care diagnostics as a case study where the software and hardware must be robust, reliable to provide accurate diagnosis of diseases. As software and software intensive systems are becoming increasingly complex, the impact of failures can lead to significant property damage, or damage to the environment. Within the medical diagnostic device software domain such failures can result in misdiagnosis leading to clinical complications and in some cases death. Software faults can arise due to the interaction among the software, the hardware, third party software and the operating environment. Unanticipated environmental changes and latent coding errors lead to operation faults despite of the fact that usually a significant effort has been expended in the design, verification and validation of the software system. It is becoming increasingly more apparent that one needs to adopt different approaches, which will guarantee that a complex software system meets all safety, security, and reliability requirements, in addition to complying with standards such as IEC 62304. There are many initiatives taken to develop safety and security critical systems, at different development phases and in different contexts, ranging from infrastructure design to device design. Different approaches are implemented to design error free software for safety critical systems. By adopting the strategies and processes presented in this paper one can overcome the challenges in developing error free software for medical devices (or safety critical systems).Brunel Open Access Publishing Fund
A rigorous definition of axial lines: ridges on isovist fields
We suggest that 'axial lines' defined by (Hillier and Hanson, 1984) as lines
of uninterrupted movement within urban streetscapes or buildings, appear as
ridges in isovist fields (Benedikt, 1979). These are formed from the maximum
diametric lengths of the individual isovists, sometimes called viewsheds, that
make up these fields (Batty and Rana, 2004). We present an image processing
technique for the identification of lines from ridges, discuss current
strengths and weaknesses of the method, and show how it can be implemented
easily and effectively.Comment: 18 pages, 5 figure
Towards a Tool-based Development Methodology for Pervasive Computing Applications
Despite much progress, developing a pervasive computing application remains a
challenge because of a lack of conceptual frameworks and supporting tools. This
challenge involves coping with heterogeneous devices, overcoming the
intricacies of distributed systems technologies, working out an architecture
for the application, encoding it in a program, writing specific code to test
the application, and finally deploying it. This paper presents a design
language and a tool suite covering the development life-cycle of a pervasive
computing application. The design language allows to define a taxonomy of
area-specific building-blocks, abstracting over their heterogeneity. This
language also includes a layer to define the architecture of an application,
following an architectural pattern commonly used in the pervasive computing
domain. Our underlying methodology assigns roles to the stakeholders, providing
separation of concerns. Our tool suite includes a compiler that takes design
artifacts written in our language as input and generates a programming
framework that supports the subsequent development stages, namely
implementation, testing, and deployment. Our methodology has been applied on a
wide spectrum of areas. Based on these experiments, we assess our approach
through three criteria: expressiveness, usability, and productivity
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