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See detailCalibration of a microscopic simulation model for emission calculation
Li, Jie; Van Zuylen, Henk J.; Chen, Yusen et al

in Transportation Research. Part C : Emerging Technologies (2013), 31

Emissions by road traffic can be reduced by optimising traffic control. The impact of this optimisation on emission can be analysed ex ante by simulation. The simulation programs used for this analysis ... [more ▼]

Emissions by road traffic can be reduced by optimising traffic control. The impact of this optimisation on emission can be analysed ex ante by simulation. The simulation programs used for this analysis should be valid with respect to the traffic characteristics that determine the emissions. Thus calibration of the parameters is a prerequisite. In most cases, volumes, travel times and queues are used to calibrate simulation models, rather than detailed driving characteristics such as speed and acceleration patterns. However, these driving behaviour parameters determine the vehicular emissions to a great extent. A study was carried out in which the driving behaviour parameters in a microscopic simulation model (VISSIM) were calibrated using real trajectories collected by image processing at an intersection in Rotterdam. The sensitivity of the simulation results for driving behaviour parameters was investigated. The most influential parameters were identified and adjusted to ensure that the simulation results were consistent with the observed traffic and could provide valid estimations of the total production of emissions. [less ▲]

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See detailCardiff/Luxembourg Computational Mechanics Research Group
Bordas, Stéphane UL; Kerfriden, Pierre; Hale, Jack UL et al

Poster (2014, November)

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See detailA Case Study On Computational Hermeneutics: E. J. Lowe's Modal Ontological Argument
Fuenmayor, David; Benzmüller, Christoph UL

in IfCoLog Journal of Logics and Their Applications (2018), 5(7), 1567-1603

Computers may help us to better understand (not just verify) arguments. In this article we defend this claim by showcasing the application of a new, computer-assisted interpretive method to an exemplary ... [more ▼]

Computers may help us to better understand (not just verify) arguments. In this article we defend this claim by showcasing the application of a new, computer-assisted interpretive method to an exemplary natural-language argument with strong ties to metaphysics and religion: E. J. Lowe’s modern variant of St. Anselm’s ontological argument for the existence of God. Our new method, which we call computational hermeneutics, has been particularly conceived for use in interactive-automated proof assistants. It aims at shedding light on the meanings of words and sentences by framing their inferential role in a given argument. By employing automated theorem reasoning technology within interactive proof assistants, we are able to drastically reduce (by several orders of magnitude) the time needed to test the logical validity of an argument’s formalization. As a result, a new approach to logical analysis, inspired by Donald Davidson’s account of radical interpretation, has been enabled. In computational hermeneutics, the utilization of automated reasoning tools effectively boosts our capacity to expose the assumptions we indirectly commit ourselves to every time we engage in rational argumentation and it fosters the explicitation and revision of our concepts and commitments. [less ▲]

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See detailA cell - based smoothed finite element method for free vibration and buckling analysis of shells
Thai-Hoang, Chien; Nguyen-Thanh, Nhon; Nguyen-Xuan, Hung et al

in KSCE Journal of Civil Engineering (2011), 15(2), 347-361

This paper further extends a cell-based smoothed finite element method for free vibration and buckling analysis of shells. A four-node quadrilateral Mindlin-Reissner shell element with a gradient ... [more ▼]

This paper further extends a cell-based smoothed finite element method for free vibration and buckling analysis of shells. A four-node quadrilateral Mindlin-Reissner shell element with a gradient smoothing operator is adopted. The membrane-bending and geometrical stiffness matrices are computed along the boundaries of the smoothing cells while the shear stiffness matrix is calculated by an independent interpolation in the natural coordinates as in the MITC4 (the Mixed Interpolation of Tensorial Components) element. Various numerical results are compared with existing exact and numerical solutions and they are in good agreement. The advantage of the present formulation is that it retains higher accurate than the MITC4 element even for heavily distorted meshes without increasing the computational cost. © 2011 Korean Society of Civil Engineers and Springer-Verlag Berlin Heidelberg. [less ▲]

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See detailCell culture apparatus and culture methods using same
Wilmes, Paul UL; Zenhausern, Frederic; Estes, Matt et al

Patent (2013)

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See detailA cell-based smoothed finite element method for kinematic limit analysis
Le, Canh. V.; Nguyen-Xuan, H.; Askes, H. et al

in International Journal for Numerical Methods in Engineering (2010), 83(12), 1651-1674

This paper presents a new numerical procedure for kinematic limit analysis problems, which incorporates the cell-based smoothed finite element method with second-order cone programming. The application of ... [more ▼]

This paper presents a new numerical procedure for kinematic limit analysis problems, which incorporates the cell-based smoothed finite element method with second-order cone programming. The application of a strain smoothing technique to the standard displacement finite element both rules out volumetric locking and also results in an efficient method that can provide accurate solutions with minimal computational effort. The non-smooth optimization problem is formulated as a problem of minimizing a sum of Euclidean norms, ensuring that the resulting optimization problem can be solved by an efficient second-order cone programming algorithm. Plane stress and plane strain problems governed by the von Mises criterion are considered, but extensions to problems with other yield criteria having a similar conic quadratic form or 3D problems can be envisaged. [less ▲]

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See detailA cell-based smoothed finite element method for three dimensional solid structures
Nguyen-Xuan, Hung; Nguyen, Ha Manh UL; Bordas, Stéphane UL et al

in KSCE Journal of Civil Engineering (2012), 16(7), 1230-1242

This paper extends further the strain smoothing technique in finite elements to 8-noded hexahedral elements (CS-FEM-H8). The idea behind the present method is similar to the cell-based smoothed 4-noded ... [more ▼]

This paper extends further the strain smoothing technique in finite elements to 8-noded hexahedral elements (CS-FEM-H8). The idea behind the present method is similar to the cell-based smoothed 4-noded quadrilateral finite elements (CS-FEM-Q4). In CSFEM, the smoothing domains are created based on elements, and each element can be further subdivided into 1 or several smoothing cells. It is observed that: 1) The CS-FEM using a single smoothing cell can produce higher stress accuracy, but insufficient rank and poor displacement accuracy; 2) The CS-FEM using several smoothing cells has proper rank, good displacement accuracy, but lower stress accuracy, especially for nearly incompressible and bending dominant problems. We therefore propose 1) an extension of strain smoothing to 8-noded hexahedral elements and 2) an alternative CS-FEM form, which associates the single smoothing cell issue with multi-smoothing cell one via a stabilization technique. Several numerical examples are provided to show the reliability and accuracy of the present formulation. [less ▲]

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See detailCellular Automata Evolution Of Leader Election
Banda, Peter UL

in Kampis, George; Karsai, István; Szathmáry, Eörs (Eds.) Advances in Artificial Life. Darwin Meets von Neumann (2011)

The leader election problem is a crucial problem in the theory of distributed algorithms, multi-agent systems as well as in sociobiology. In this paper we investigate one-dimensional binary state cellular ... [more ▼]

The leader election problem is a crucial problem in the theory of distributed algorithms, multi-agent systems as well as in sociobiology. In this paper we investigate one-dimensional binary state cellular automata with an intention to track self-organizational mechanisms that finally enable a global leader to be elected. Since our model is anonymous and uniform we also have to deal with a problem of symmetry that in great majority of cases is broken by inhomogeneity of arbitrary initial configurations. Our approach to the problem is based on the evolution of cellular automata by genetic algorithms and the methodology of computational mechanics. The presented new solution of the leader election reaches remarkably high performance of 94 − 99%. The analysis shows a sophisticated collective computation demonstrated by so called particles and their interactions. Due to the simplicity of our model, presented approach is general and universal enough to be applicable even at the level of primitive biological or artificial societies. [less ▲]

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See detailCentralized and decomposed anticipatory Model Predictive Control for network-wide Ramp Metering
Rinaldi, Marco UL; Tampere, C. M. J.; Himpe, W. et al

in Proceedings of the 16th International IEEE Conference on Intelligent Transportation Systems: Intelligent Transportation Systems for All Modes, ITSC 2013 (2013)

The problem of determining Ramp Metering control rates, taking into account routing response, is addressed in this paper. We develop Model Predictive Control based Anticipatory control schemes, featuring ... [more ▼]

The problem of determining Ramp Metering control rates, taking into account routing response, is addressed in this paper. We develop Model Predictive Control based Anticipatory control schemes, featuring both centralized and decomposed optimization problems, with focus on real-life deployability. We then evaluate the aforementioned schemes' performances in comparison to simpler, non-anticipatory control techniques, by means of software simulation based on purpose-built experimental scenarios. © 2013 IEEE. [less ▲]

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See detailCertification of projection-based reduced order modelling in computational homogenisation by the Constitutive Relation Error
Kerfriden, Pierre; Ródenas, Juan-José; Bordas, Stéphane UL

in International Journal for Numerical Methods in Engineering (2014), 97(6), 395-422

In this paper, we propose upper and lower error bounding techniques for reduced order modelling applied to the computational homogenisation of random composites. The upper bound relies on the construction ... [more ▼]

In this paper, we propose upper and lower error bounding techniques for reduced order modelling applied to the computational homogenisation of random composites. The upper bound relies on the construction of a reduced model for the stress field. Upon ensuring that the reduced stress satisfies the equilibrium in the nite element sense, the desired bounding property is obtained. The lower bound is obtained by defining a hierarchical enriched reduced model for the displacement. We show that the sharpness of both error estimates can be seamlessly controlled by adapting the parameters of the corresponding reduced order model. [less ▲]

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See detailCertification of projection-based reduced order modelling in computational homogenisation by the constitutive relation error
Kerfriden, P.; Ródenas, J. J.; Bordas, Stéphane UL

in International Journal for Numerical Methods in Engineering (2013)

SUMMARY: In this paper, we propose upper and lower error bounding techniques for reduced order modelling applied to the computational homogenisation of random composites. The upper bound relies on the ... [more ▼]

SUMMARY: In this paper, we propose upper and lower error bounding techniques for reduced order modelling applied to the computational homogenisation of random composites. The upper bound relies on the construction of a reduced model for the stress field. Upon ensuring that the reduced stress satisfies the equilibrium in the finite element sense, the desired bounding property is obtained. The lower bound is obtained by defining a hierarchical enriched reduced model for the displacement. We show that the sharpness of both error estimates can be seamlessly controlled by adapting the parameters of the corresponding reduced order model. © 2013 John Wiley & Sons, Ltd. [less ▲]

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See detailChallenges Ahead For Modelling And Simulation In Mechanics: From Engineering To Medicine
Aifantis, Elias; Kerfriden, Pierre; Bordas, Stéphane UL

Scientific Conference (2014, July 01)

Detailed reference viewed: 218 (1 UL)
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See detailChapter 4:A Survey on The Polytopic Takagi-Sugeno Approach: Application to the Inverted Pendulum
Bezzaoucha, Souad UL; Voos, Holger UL; Darouach, Mohamed

in The Inverted Pendulum: From Theory to New Innovations in Control and Robotics (2017)

This book chapter gives a general scope, states the main results obtained and methods used for the Polytopic Takagi-Sugeno approach with a detailed application to the inverted pendulum. Modeling, observer ... [more ▼]

This book chapter gives a general scope, states the main results obtained and methods used for the Polytopic Takagi-Sugeno approach with a detailed application to the inverted pendulum. Modeling, observer and controller design will be considered. [less ▲]

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See detailThe circadian oscillator gene GIGANTEA mediates a long-term response of the Arabidopsis thaliana circadian clock to sucrose
Dalchau, Neil; Baek, Seong; Briggs, Helen et al

in PNAS (2011), 108(12), 51045109

Circadian clocks are 24-h timing devices that phase cellular responses; coordinate growth, physiology, and metabolism; and anticipate the day–night cycle. Here we report sensitivity of the Arabidopsis ... [more ▼]

Circadian clocks are 24-h timing devices that phase cellular responses; coordinate growth, physiology, and metabolism; and anticipate the day–night cycle. Here we report sensitivity of the Arabidopsis thaliana circadian oscillator to sucrose, providing evidence that plant metabolism can regulate circadian function. We found that the Arabidopsis circadian system is particularly sensitive to sucrose in the dark. These data suggest that there is a feedback between the molecular components that comprise the circadian oscillator and plant metabolism, with the circadian clock both regulating and being regulated by metabolism. We used also simulations within a three-loop mathematical model of the Arabidopsis circadian oscillator to identify components of the circadian clock sensitive to sucrose. The mathematical studies identified GIGANTEA (GI) as being associatedwith sucrose sensing. Experimental validation of this prediction demonstrated that GI is required for the full response of the circadian clock to sucrose. We demonstrate that GI acts as part of the sucrose-signaling network and propose this role permits metabolic input into circadian timing in Arabidopsis. [less ▲]

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See detailClassification of states and model order reduction of large scale Chemical Vapor Deposition processes with solution multiplicity
Koronaki, E.D.; Gkinis, P.A.; Beex, Lars UL et al

in Computers and Chemical Engineering (2018), 121

This paper presents an equation-free, data-driven approach for reduced order modeling of a Chemical Vapor Deposition (CVD) process. The proposed approach is based on process information provided by ... [more ▼]

This paper presents an equation-free, data-driven approach for reduced order modeling of a Chemical Vapor Deposition (CVD) process. The proposed approach is based on process information provided by detailed, high-fidelity models, but can also use spatio-temporal measurements. The Reduced Order Model (ROM) is built using the method-of-snapshots variant of the Proper Orthogonal Decomposition (POD) method and Artificial Neural Networks (ANN) for the identification of the time-dependent coefficients. The derivation of the model is completely equation-free as it circumvents the projection of the actual equations onto the POD basis. Prior to building the model, the Support Vector Machine (SVM) supervised classification algorithm is used in order to identify clusters of data corresponding to (physically) different states that may develop at the same operating conditions due to the inherent nonlinearity of the process. The different clusters are then used for ANN training and subsequent development of the ROM. The results indicate that the ROM is successful at predicting the dynamic behavior of the system in windows of operating parameters where steady states are not unique. [less ▲]

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See detailClassifying and Extracting Elements of Norms for Ontology Population using Semantic Role Labelling
Humphreys, Llio UL; Boella, Guido; Robaldo, Livio UL et al

in The 15th International Conference on Artificial Intelligence & Law — San Diego, June 8-12, 2015 (2015)

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See detailClinical data based optimal STI strategies for HIV: a reinforcement learning approach
Ernst, D.; Stan, G.B.; Goncalves, Jorge UL et al

in Proceedings of the IEEE Conference on Decision and Control (2006)

This paper addresses the problem of computing optimal structured treatment interruption strategies for HIV infected patients. We show that reinforcement learning may be useful to extract such strategies ... [more ▼]

This paper addresses the problem of computing optimal structured treatment interruption strategies for HIV infected patients. We show that reinforcement learning may be useful to extract such strategies directly from clinical data, without the need of an accurate mathematical model of HIV infection dynamics. To support our claims, we report simulation results obtained by running a recently proposed batch-mode reinforcement learning algorithm, known as fitted Q iteration, on numerically generated data. [less ▲]

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See detailCloud Providers Viability: How to Address it from an IT and Legal Perspective?
Bartolini, Cesare UL; El Kateb, Donia; Le Traon, Yves UL et al

in Electron Markets (2018), 28(1), 53-75

A major part of the commercial Internet is moving toward the cloud paradigm. This phenomenon has a drastic impact onthe organizational structures of enterprizes and introduces new challenges that must be ... [more ▼]

A major part of the commercial Internet is moving toward the cloud paradigm. This phenomenon has a drastic impact onthe organizational structures of enterprizes and introduces new challenges that must be properly addressed to avoid majorsetbacks. One such challenge is that of cloud provider viability, that is, the reasonable certainty that the Cloud ServiceProvider (CSP) will not go out of business, either by filing for bankruptcy or by simply shutting down operations, thusleaving its customers stranded without an infrastructure and, depending on the type of cloud service used, even withouttheir applications or data. This article attempts to address the issue of cloud provider viability, defining a possible way ofmodeling viability as a non-functional requirement and proposing some approaches that can be used to mitigate the problem,both from a technical and from a legal perspective. By introducing a structured perspective into the topic of cloud viability,describing the risks, factors and possible mitigators, the contribution of this work is twofold: it gives the customer a betterunderstanding to determine when it can rely on the cloud infrastructure on the long term and what precautions it should takein any case, and provides the CSP with means to address some of the viability issues and thus increase its customers’ trust. [less ▲]

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See detailCloud Providers Viability: How to Address it from an IT and Legal Perspective?
Bartolini, Cesare UL; El Kateb, Donia UL; Le Traon, Yves UL et al

in Altmann, Jörn; Silaghi, Gheorghe Cosmin; Rana, Omer F. (Eds.) Economics of Grids, Clouds, Systems, and Services (2016)

A major part of the commercial Internet is moving towards a cloud paradigm. This phenomenon has a drastic impact on the organizational structures of enterprises and introduces new challenges that must be ... [more ▼]

A major part of the commercial Internet is moving towards a cloud paradigm. This phenomenon has a drastic impact on the organizational structures of enterprises and introduces new challenges that must be properly addressed to avoid major setbacks. One such challenge is that of cloud provider viability, that is, the reasonable certainty that the Cloud Service Provider (CSP) will not go out of business, either by filing for bankruptcy or by simply shutting down operations, thus leaving its customers stranded without an infrastructure and, depending on the type of cloud service used, even without their applications or data. This article attempts to address the issue of cloud provider viability, proposing some ways of mitigating the problem both from a technical and from a legal perspective. [less ▲]

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See detailCloud Providers Viability: How to Address it from an IT and Legal Perspective?
Bartolini, Cesare UL; El Kateb, Donia UL; Le Traon, Yves UL et al

in Economics of Grids, Clouds, Systems, and Services (2015, September 16)

A major part of the commercial Internet is moving towards a cloud paradigm. This phenomenon has a drastic impact on the organizational structures of enterprises and introduces new challenges that must be ... [more ▼]

A major part of the commercial Internet is moving towards a cloud paradigm. This phenomenon has a drastic impact on the organizational structures of enterprises and introduces new challenges that must be properly addressed to avoid major setbacks. One such challenge is that of cloud provider viability, that is, the reasonable certainty that the Cloud Service Provider (CSP) will not go out of business, either by filing for bankruptcy or by simply shutting down operations, thus leaving its customers stranded without an infrastructure and, depending on the type of cloud service used, even without their applications or data. This article attempts to address the issue of cloud provider viability, proposing some ways of mitigating the problem both from a technical and from a legal perspective. [less ▲]

Detailed reference viewed: 183 (15 UL)