Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
See detailFM Discriminator for AIS Satellite Detection
Jurado Gallardo, Maria De Los Angeles UL; Ruy, Ghislain

in Personal Satellite Services (2010)

The Automatic Identification System (AIS) is a tracking system used on ships for several decades to improve traffic monitoring and safety at sea in a short range. The modulation technique used is Gaussian ... [more ▼]

The Automatic Identification System (AIS) is a tracking system used on ships for several decades to improve traffic monitoring and safety at sea in a short range. The modulation technique used is Gaussian Minimum Shift Keying (GMSK). Recently, the idea of receiving AIS signals from space arose. This presents mainly two challenges. The first one is that received signals present a large Doppler range due to the satellite speed. The second one is the simultaneous reception of signals from ships because of the broad satellite coverage. In this paper, a novel non-coherent GMSK demodulator is proposed to handle the large Doppler shift problem based on several FM discriminators in parallel. A frame collision detection algorithm is presented but the collision problem is not addressed. In addition, computer simulated and real signals are used to study the receiver performance on an AWGN channel. [less ▲]

Detailed reference viewed: 218 (0 UL)
Full Text
Peer Reviewed
See detailA force-based large increment method for 2D continuum solids and the mesh convergence study
Long, D.; Guo, Z.; Liu, X. et al

in AIP Conference Proceedings (2012), 1504

In this paper, a triangular plane stress element is implemented based on the large increment method (LIM) to solve 2D continuum mechanics problems. In the LIM, after the governing equations are ... [more ▼]

In this paper, a triangular plane stress element is implemented based on the large increment method (LIM) to solve 2D continuum mechanics problems. In the LIM, after the governing equations are established using the generalized elemental force variables as primary unknowns, an iteration procedure is employed to obtain an optimised approximate solution of the problem. Two numerical examples are investigated to study the mesh convergence of the proposed triangular LIM element. Structured meshes as well as unstructured meshes with different element densities are generated to illustrate the convergence of the total strain energy in both examples. The numerical results obtained from the LIM (including the total strain energy, the displacement and the stress) are compared with the analytical solutions as well as the results from the commercial FEM software ABAQUS. All the results show that the performance of the LIM is as good as the FEM in linear elastic problems. A simple elastoplastic example suggests that the LIM may obtain better result than the FEM. © 2012 American Institute of Physics. [less ▲]

Detailed reference viewed: 324 (5 UL)
Full Text
Peer Reviewed
See detailFostering sustainable user behaviour: exploring meaning and its creation in products and services
Waltersdorfer, Gregor UL; Gericke, Kilian UL; Blessing, Lucienne UL

in Valentine, Louise; Borja de Mozota, Brigitte; Nelson, Julien (Eds.) et al The Value of Design Research, Proceedings of the 11th International Conference of the European Academy of Design (2015)

This paper is integrated in our research project on fostering sustainable user behaviour by designing meaning. It explores different types of meaning in products and services, and their creation. For that ... [more ▼]

This paper is integrated in our research project on fostering sustainable user behaviour by designing meaning. It explores different types of meaning in products and services, and their creation. For that, the results of a literature study are integrated into an initial taxonomy of meaning and an initial framework for creating meaning. From the taxonomy we derive four roles that products and services can play in meaning making. Additionally we discuss how five possible interventions in users meaning making for behavioural change can be pursued by design on the basis of the framework. We illustrate the role of designers in creating meaning with examples, touch on its potential for behavioural change of users and outline further research needs. [less ▲]

Detailed reference viewed: 218 (18 UL)
Full Text
See detailFracture in augmented reality
Bilger, Alexandre UL; Cotin, Stephane; Dequidt, Jeremie et al

Poster (2015, August)

Detailed reference viewed: 142 (1 UL)
Full Text
Peer Reviewed
See detailFracture mechanism simulation of inhomogeneous anisotropic rocks by extended finite element method
Mohtarami, Ehsan; Baghbanan, Alireza; Hashemolhosseini, Hamid et al

in Theoretical and Applied Fracture Mechanics (2019), 104

The vast majority of rock masses is anisotropic due to factors such as layering, unequal in-situ stresses, joint sets, and discontinuities. Meanwhile, given the frequently asymmetric distribution of pores ... [more ▼]

The vast majority of rock masses is anisotropic due to factors such as layering, unequal in-situ stresses, joint sets, and discontinuities. Meanwhile, given the frequently asymmetric distribution of pores, grain sizes or different mineralogical compounds in different locations, they are often classified as inhomogeneous materials. In such materials, stress intensity factors (SIFs) at the crack tip, which control the initiation of failure, strongly depend on mechanical properties of the material near that area. On the other hand, crack propagation trajectories highly depend on the orthotropic properties of the rock mass. In this study, the SIFs are calculated by means of anisotropic crack tip enrichments and an interaction integral are developed for inhomogeneous materials with the help of the extended finite element method (XFEM). We also use the T-stress within the crack tip fields to develop a new criterion to estimate the crack initiation angles and propagation in rock masses. To verify and validate the proposed approach, the results are compared with experimental test results and those reported in the literature. It is found that the ratio of elastic moduli, shear stiffnesses, and material orientation angles have a significant impact on the SIFs. However, the rate of change in material properties is found to have a moderate effect on these factors and a more pronounced effect on the failure force. The results highlight the potential of the proposed formulation in the estimation of SIFs and crack propagation paths in inhomogeneous anisotropic materials. [less ▲]

Detailed reference viewed: 87 (0 UL)
Full Text
Peer Reviewed
See detailA Framework for Comparing Design Modelling Approaches Across Disciplines
Eisenbart, Boris UL; Gericke, Kilian UL; Blessing, Lucienne UL

in Proceedings of the 18th International Conference on Engineering Design (2011)

Design models are an important means for the representation of design information in product development processes. Designers use design models to visualise and communicate their ideas to other members of ... [more ▼]

Design models are an important means for the representation of design information in product development processes. Designers use design models to visualise and communicate their ideas to other members of a design team, the project manager or a costumer. Communication between experts from different disciplines using design models is often hindered by different terminology and different ways of modelling. Potential consequences are design flaws, which may lead to time-consuming iterations and – if undetected – to problems during production or use. In order to enhance the communication through design models across disciplines, and to address the mentioned problems, an understanding of similarities as well as differences between modelling approaches needs to be established. For that purpose, this paper discusses different design states which represent a distinct level of available information in the development process. They are derived through comparing different design models proposed in literature and provide the basis of a framework for a detailed comparison of modelling approaches across disciplines. Further, first insights into different ways of modelling are discussed. [less ▲]

Detailed reference viewed: 108 (2 UL)
Full Text
Peer Reviewed
See detailThe Framework of Security-Enhancing Friction: How UX Can Help Users Behave More Securely
Distler, Verena UL; Lenzini, Gabriele UL; Lallemand, Carine UL et al

in New Security Paradigms Workshop (2020, October 26)

A growing body of research in the usable privacy and security community addresses the question of how to best influence user behavior to reduce risk-taking.We propose to address this challenge by ... [more ▼]

A growing body of research in the usable privacy and security community addresses the question of how to best influence user behavior to reduce risk-taking.We propose to address this challenge by integrating the concept of user experience (UX) into empirical usable privacy and security studies that attempt to change risktaking behavior. UX enables us to study the complex interplay between user-related, system-related and contextual factors and provides insights into the experiential aspects underlying behavior change, including negative experiences. We first compare and contrast existing security-enhancing interventions (e.g., nudges, warnings, fear appeals) through the lens of friction. We then build on these insights to argue that it can be desirable to design for moments of negative UX in security-critical situations. For this purpose, we introduce the novel concept of security-enhancing friction, friction that effectively reduces the occurrence of risk-taking behavior and ensures that the overall UX (after use) is not compromised. We illustrate how security-enhancing friction provides an actionable way to systematically integrate the concept of UX into empirical usable privacy and security studies for meeting both the objectives of secure behavior and of overall acceptable experience. [less ▲]

Detailed reference viewed: 212 (41 UL)
Full Text
Peer Reviewed
See detailA Framework to Reason about the Legal Compliance of Security Standards
Bartolini, Cesare UL; Giurgiu, Andra UL; Lenzini, Gabriele UL et al

in Proceedings of the Tenth International Workshop on Juris-informatics (JURISIN) (2016, November)

Achieving compliance with legal regulations is no easy task. Normally, laws state general requirements but do not provide clear parameters to determine when such requirements are met. On a different level ... [more ▼]

Achieving compliance with legal regulations is no easy task. Normally, laws state general requirements but do not provide clear parameters to determine when such requirements are met. On a different level, industrial standards and best practices define specific objectives that can be certified by means of auditing procedures from qualified bodies. Implementing a standard does not per se guarantee legal compliance, with the rare exception when the standard is also endorsed by the law itself. But standards and laws in the same domain may have overlaps and correlations, so adopting the former may provide an argument to demonstrate that adequate measures were taken to achieve legal compliance. In this paper, we introduce a framework that, using state-of-the-art Natural Language Semantics techniques, helps process legal documents and standards to build a knowledge base to store their logic representations, and the correlations between them. The knowledge base will help legal experts assess what requirements of the law are met by the standard and, consequently, recognize what requirements still need to be implemented to fill the remaining gaps. An application of the framework is exemplified by comparing a provision of the European General Data Protection Regulation against the ISO/IEC 27001:2013 standard. [less ▲]

Detailed reference viewed: 420 (38 UL)
Full Text
See detailFree boundary problems: numerical methods and data-driven simulations
Bordas, Stéphane UL

Presentation (2018, March 05)

Detailed reference viewed: 159 (12 UL)
Full Text
Peer Reviewed
See detailFrictional interactions for non-localised beam-to-beam and beam-inside-beam contact
Magliulo, Marco; Lengiewicz, Jakub UL; Zilian, Andreas UL et al

in International Journal for Numerical Methods in Engineering (2021), 122(7), 1706-1731

This contribution presents the extensions of beam-to-beam and beam-inside-beam contact schemes of the same authors towards frictional interactions. Since the schemes are based on the beams’ true surfaces ... [more ▼]

This contribution presents the extensions of beam-to-beam and beam-inside-beam contact schemes of the same authors towards frictional interactions. Since the schemes are based on the beams’ true surfaces (instead of surfaces implicitly deduced from the beams’ centroid lines), the presented enhancements are not only able to account for frictional sliding in the beams’ axial directions, but also in the circumferential directions. Both the frictional beam-to-beam approach as well as the frictional beam-inside-beam approach are applicable to shear-deformable and shear-undeformable beams, as well as to beams with both circular and elliptical cross-sections (although the cross-sections must be rigid). A penalty formulation is used to treat unilateral and frictional contact constraints. FE implementation details are discussed, where automatic differentiation techniques are used to derive the implementations. Simulations involving large sliding displacements and large deformations are presented for both beam-to-beam and beam-inside-beam schemes. All simulation results are compared to those of the frictionless schemes. [less ▲]

Detailed reference viewed: 90 (6 UL)
See detailFriendly Batch Routing (FBR)
Medard de Chardon, Cyrille UL; Caruso, Geoffrey UL

Software (2012)

The Friendly Batch Routing (FBR) application uses the Google Maps API to easily and simply gather route data for many origin-destination pairs. FBR is designed with usability in mind so that errors do not ... [more ▼]

The Friendly Batch Routing (FBR) application uses the Google Maps API to easily and simply gather route data for many origin-destination pairs. FBR is designed with usability in mind so that errors do not interrupt processing and skipped records can easily be resubmitted for processing. Additionally the FBR output can easily be imported into GIS packages. [less ▲]

Detailed reference viewed: 285 (12 UL)
Full Text
Peer Reviewed
See detailFrom Digitized Sources to Digital Data, Behind the Scenes of (Critically) Enriching a Digital Heritage Collection
Viola, Lorella UL; Fiscarelli, Antonio Maria

in Weber, Andreas; Heerlien, Maarten; Gassó Miracle, Eulàlia (Eds.) et al Proceedings of the International Conference Collect and Connect: Archives and Collections in a Digital Age (2020)

Digitally available repositories are becoming not only more and more widespread but also larger and larger. Although there are both digitally-born collections and digitised material, the digital heritage ... [more ▼]

Digitally available repositories are becoming not only more and more widespread but also larger and larger. Although there are both digitally-born collections and digitised material, the digital heritage scholar is typically confronted with the latter. This immediately presents new challenges, one of the most urgent being how to find the meaningful elements that are hidden underneath such unprecedented mass of digital data. One way to respond to this challenge is to contextually enrich the digital material, for example through deep learning. Using the enrichment of the digital heritage collection ChroniclItaly 3.0 [10] as a concrete example, this article discusses the complexities of this process. Specifically, combining statistical and critical evaluation, it describes the gains and losses resulting from the decisions made by the researcher at each step and it shows how in the passage from digitised sources to enriched material, most is gained (e.g., preservation, wider and enhanced access, more material) but some is also lost (e.g., original layout and composition, loss of information due to pre-processing steps). The article concludes that it is only through a critical approach that the digital heritage scholar can successfully meet the interpretive challenges presented by the digital and the digital heritage sector fulfil the second most important purpose of digitisation, that is to enhance access. [less ▲]

Detailed reference viewed: 18 (0 UL)
Full Text
See detailFrom image to analysis: an extended finite element method to simulate the mechanical response of soft-tissue
Hale, Jack UL; Bordas, Stéphane UL; Kerfriden, Pierre

Presentation (2014, April 10)

In this seminar we consider the problem of constructing a numerical method particularly well suited to modelling domains described by segmented image data of the human body. Instead of constructing a ... [more ▼]

In this seminar we consider the problem of constructing a numerical method particularly well suited to modelling domains described by segmented image data of the human body. Instead of constructing a conforming mesh of the problem domain, we use implicitly defined domains described using the level-set method. We then include information about the implicitly defined domains by enriching the usual finite element basis functions defined on a cartesian quadtree or octree mesh with hanging nodes. This approach introduces significant complexities compared with classical finite element methods. We will discuss difficulties with the treatment of hanging nodes, numerical integration and imposing Dirichlet boundary conditions. We will discuss the possible future of extensions of this work, including cutting of soft tissue, multiscale problems with complex microstructure, and model order reduction problems. [less ▲]

Detailed reference viewed: 170 (8 UL)
Full Text
Peer Reviewed
See detailA fully smoothed XFEM for analysis of axisymmetric problems with weak discontinuities
Wan, Detao; Hu, Dean; Natarajan, Sundararajan et al

in International Journal for Numerical Methods in Engineering (2017), 110(3), 203-226

In this paper, we propose a fully smoothed extended finite element method (SmXFEM) for axisymmetric problems with weak discontinuities. The salient feature of the proposed approach is that all the terms ... [more ▼]

In this paper, we propose a fully smoothed extended finite element method (SmXFEM) for axisymmetric problems with weak discontinuities. The salient feature of the proposed approach is that all the terms in the stiffness and mass matrixes can be computed by smoothing technique. This is accomplished by combining the Green’s divergence theorem with the evaluation of indefinite integral based on smoothing technique, which is used to transform the domain integral into boundary integral. The proposed technique completely eliminates the need for isoparametric mapping and the computing of Jacobian matrix even for the mass matrix. When employed over the enriched elements, the proposed technique does not require sub-triangulation for the purpose of numerical integration. The accuracy and convergence properties of the proposed technique are demonstrated with a few problems in elastostatics and elastodynamics with weak discontinuities. It can be seen that the proposed technique yields stable and accurate solutions and is less sensitive to mesh distortion. [less ▲]

Detailed reference viewed: 133 (2 UL)
Full Text
Peer Reviewed
See detailFully-Actuated Aerial Manipulator for Infrastructure Contact Inspection: Design, Modeling, Localization, and Control
Sanchez Cuevas, Pedro Jesus UL; Gonzalez Morgado, Antonio; Cortes, Nicolas et al

in Sensors (2020)

This paper presents the design, modeling and control of a fully actuated aerial robot for infrastructure contact inspection as well as its localization system. Health assessment of transport ... [more ▼]

This paper presents the design, modeling and control of a fully actuated aerial robot for infrastructure contact inspection as well as its localization system. Health assessment of transport infrastructure involves measurements with sensors in contact with the bridge and tunnel surfaces and the installation of monitoring sensing devices at specific points. The design of the aerial robot presented in the paper includes a 3DoF lightweight arm with a sensorized passive joint which can measure the contact force to regulate the force applied with the sensor on the structure. The aerial platform has been designed with tilted propellers to be fully actuated, achieving independent attitude and position control. It also mounts a “docking gear” to establish full contact with the infrastructure during the inspection, minimizing the measurement errors derived from the motion of the aerial platform and allowing full contact with the surface regardless of its condition (smooth, rough, ...). The localization system of the aerial robot uses multi-sensor fusion of the measurements of a topographic laser sensor on the ground and a tracking camera and inertial sensors on-board the aerial robot, to be able to fly under the bridge deck or close to the bridge pillars where GNSS satellite signals are not available. The paper also presents the modeling and control of the aerial robot. Validation experiments of the localization system and the control system, and with the aerial robot inspecting a real bridge are also included. [less ▲]

Detailed reference viewed: 38 (0 UL)
Full Text
Peer Reviewed
See detailFunctional Modelling Perspectives Across Disciplines: A Literature Review
Eisenbart, Boris UL; Blessing, Lucienne UL; Gericke, Kilian UL

in Proceedings of the 12th International Design Conference - DESIGN 2012 (2012)

The research presented in this paper discusses the different understandings of function which hamper shared functional modelling. Function models proposed in literature from various disciplines are then ... [more ▼]

The research presented in this paper discusses the different understandings of function which hamper shared functional modelling. Function models proposed in literature from various disciplines are then analysed, in order to identify the different inherent functional modelling perspectives. The paper concludes that in order to support shared functional modelling and to support cross-disciplinary system development, these different functional modelling perspectives need to be linked. [less ▲]

Detailed reference viewed: 111 (7 UL)
Full Text
Peer Reviewed
See detailFundamental Solutions and Dual Boundary Element Method for Crack Problems in Plane Cosserat Elasticity
Atroshchenko, Elena; Bordas, Stéphane UL

in Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences (2014)

In this paper, both singular and hypersingular fundamental solutions of plane Cosserat elasticity are derived and given in a ready-to-use form. The hypersingular fundamental solutions allow to formulate ... [more ▼]

In this paper, both singular and hypersingular fundamental solutions of plane Cosserat elasticity are derived and given in a ready-to-use form. The hypersingular fundamental solutions allow to formulate the analogue of Somigliana stress identity, which can be used to obtain the stress and couple stress fields inside the domain from the boundary values of the displacements, microrotation and stress and couple stress tractions. Using these newly derived fundamental solutions, the boundary integral equations of both types are formulated and solved by the boundary element method. Simultaneous use of both types of the equations (approach known as the dual BEM) allows to treat problems where parts of the boundary are overlapping, such as crack problems, and to do this for general geometry and loading conditions. The high accuracy of the boundary element method for both types of equations is demonstrated for a number of benchmark problems, including a Griffith crack problem and a plate with an edge crack. The detailed comparison of the BEM-results and the analytical solution for a Griffith crack is given, particularly, in terms of stress and couple stress intensity factors, as well as the crack opening displacements and microrotations on the crack faces. A modified method for computing the couple stress intensity factors is also proposed and evaluated. Finally, the asymptotic behavior of the solution to the Cosserat crack problems, in the vicinity of the crack tip is analyzed. [less ▲]

Detailed reference viewed: 692 (13 UL)
Full Text
Peer Reviewed
See detailFundamental solutions and dual boundary element methods for fracture in plane Cosserat elasticity
Atroshchenko, Elena; Bordas, Stéphane UL

in Proceedings of the Royal Society a-Mathematical Physical and Engineering Sciences (2015), 471(2179),

In this paper, both singular and hypersingular fundamental solutions of plane Cosserat elasticity are derived and given in a ready-to-use form. The hypersingular fundamental solutions allow to formulate ... [more ▼]

In this paper, both singular and hypersingular fundamental solutions of plane Cosserat elasticity are derived and given in a ready-to-use form. The hypersingular fundamental solutions allow to formulate the analogue of Somigliana stress identity, which can be used to obtain the stress and couple-stress fields inside the domain from the boundary values of the displacements, microrotation and stress and couple-stress tractions. Using these newly derived fundamental solutions, the boundary integral equations of both types are formulated and solved by the boundary element method. Simultaneous use of both types of equations (approach known as the dual boundary element method (BEM)) allows problems where parts of the boundary are overlapping, such as crack problems, to be treated and to do this for general geometry and loading conditions. The high accuracy of the boundary element method for both types of equations is demonstrated for a number of benchmark problems, including a Griffith crack problem and a plate with an edge crack. The detailed comparison of the BEM results and the analytical solution for a Griffith crack and an edge crack is given, particularly in terms of stress and couple-stress intensity factors, as well as the crack opening displacements and microrotations on the crack faces and the angular distributions of stresses and couple-stresses around the crack tip. [less ▲]

Detailed reference viewed: 120 (2 UL)
Full Text
Peer Reviewed
See detailFusing the Seth-Hill strain tensors to fit compressible elastic material responses in the nonlinear regime
Beex, Lars UL

in International Journal of Mechanical Sciences (2019), 163

Strain energy densities based on the Seth-Hill strain tensors are often used to describe the hyperelastic mechanical behaviours of isotropic, transversely isotropic and orthotropic materials for ... [more ▼]

Strain energy densities based on the Seth-Hill strain tensors are often used to describe the hyperelastic mechanical behaviours of isotropic, transversely isotropic and orthotropic materials for relatively large deformations. Since one parameter distinguishes which strain tensor of the Seth-Hill family is used, one has in theory the possibility to t the material response in the nonlinear regime. Most often for compressible deformations however, this parameter is selected such that the Hencky strain tensor is recovered, because it yields rather physical stress-strain responses. Hence, the response in the nonlinear regime is in practise not often tailored to match experimental data. To ensure that elastic responses in the nonlinear regime can more accurately be controlled, this contribution proposes three generalisations that combine several Seth-Hill strain tensors. The generalisations are formulated such that the stress-strain responses for in finitesimal deformations remain unchanged. Consequently, the identifi cation of the Young's moduli, Poisson's ratios and shear moduli is not a ffected. 3D fi nite element simulations are performed for isotropy and orthotropy, with an emphasis on the identifi cation of the new material parameters. [less ▲]

Detailed reference viewed: 176 (5 UL)
Full Text
See detailFuture Issues in Design Research
Blessing, Lucienne UL

in Lindemann, Udo (Ed.) Human Behaviour in Design. Individuals, Teams, Tools (2003)

This chapter contains in its first part the core future issues I derived from the presentations and discussion sessions at the conference on "Human Behvaiour and Design : Individuals, Teams, Tools" as ... [more ▼]

This chapter contains in its first part the core future issues I derived from the presentations and discussion sessions at the conference on "Human Behvaiour and Design : Individuals, Teams, Tools" as well as personal reflections. The second part presents my personal views on the most urgent issues in the area of human behaviour in design, and ways to proceed. [less ▲]

Detailed reference viewed: 115 (0 UL)