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
Full Text
Peer Reviewed
See detailAn Analysis of Functional Modelling Approaches Across Disicplines
Eisenbart, Boris UL; Gericke, Kilian UL; Blessing, Lucienne UL

in AI EDAM: Artificial Intelligence for Engineering Design Analysis and Manufacturing (2013), 27(3),

Authors across disciplines propose functional modeling as part of systematic design approaches, in order to support and guide designers during conceptual design. The presented research aims at ... [more ▼]

Authors across disciplines propose functional modeling as part of systematic design approaches, in order to support and guide designers during conceptual design. The presented research aims at contributing to a better understanding of the diverse functional modeling approaches proposed across disciplines. The article presents a literature review of 41 modeling approaches from a variety of disciplines. The analysis focuses on what is addressed by functional modeling at which point in the proposed conceptual design process (i.e., in which sequence). The gained insights lead to the identification of specific needs and opportunities, which could support the development of an integrated functional modeling approach. The findings suggest that there is no such shared sequence for functional modeling across disciplines. However, a shared functional modeling perspective has been identified across all reviewed disciplines, which could serve as a common basis for the development of an integrated functional modeling approach. [less ▲]

Detailed reference viewed: 259 (16 UL)
Full Text
Peer Reviewed
See detailAnalysis of functionally graded material plates using triangular elements with cell-based smoothed discrete shear gap method
Natarajan, S; Ferreira; Bordas, Stéphane UL et al

in Mathematical Problems in Engineering (2014), Article ID 247932

In this paper, a cell based smoothed finite element method with discrete shear gap technique is employed to study the static bending, free vibration, mechanical and thermal buckling behaviour of ... [more ▼]

In this paper, a cell based smoothed finite element method with discrete shear gap technique is employed to study the static bending, free vibration, mechanical and thermal buckling behaviour of functionally graded material (FGM) plates. The plate kinematics is based on the first order shear deformation theory and the shear locking is suppressed by a discrete shear gap method. The shear correction factors are evaluated by employing the energy equivalence principle. The material property is assumed to be temperature dependent and graded only in the thickness direction. The effective properties are computed by using the Mori-Tanaka homogenization method. The accuracy of the present formulation is validated against available solutions. A systematic parametric study is carried out to examine the influence the gradient index, the plate aspect ratio, skewness of the plate and the boundary conditions on the global response of the FGM plates. The effect of a centrally located circular cutout on the global response is also studied. [less ▲]

Detailed reference viewed: 376 (9 UL)
Full Text
See detailAnalysis of the impact of ROS in networks describing neurodegenerative diseases
Ignatenko, Andrew UL

Doctoral thesis (2016)

In the current thesis the model of the ROS management network is built using the domino principle. The model offers insight into the design principles underlying the ROS management network and enlightens ... [more ▼]

In the current thesis the model of the ROS management network is built using the domino principle. The model offers insight into the design principles underlying the ROS management network and enlightens its functionality in the diseases such as cancer and Parkinson’s disease (PD). It is validated using experimental data. The model is used for in silico study of the ROS management dynamics under the stress conditions (oxidative stress). This highlights the phenomena of both adaptation to stress and the stress accumulation effect in case of repeated stress. This study also helps to discover the potential ways to a personalized treatment of the insufficient ROS management. The different ways of a control of the ROS management network are shown using the optimal control approach. Obtained results could be used for a seeking of the treatment strategies to fix the ROS management failures caused by an oxidative stress, neurodegenerative diseases, etc. Or, in vice versa, to develop the ways of a controllable cell death that might be used in cancer research. [less ▲]

Detailed reference viewed: 111 (13 UL)
Full Text
Peer Reviewed
See detailAnalysis of thermoelastic waves in a two-dimensional functionally graded materials domain by the Meshless Local Petrov-Galerkin (MLPG) method
Ahmad Akbari, R.; Bagri, Akbar; Bordas, Stéphane UL et al

in Computer Modeling in Engineering and Sciences (2010), 65(1), 27-74

This contribution focuses on the simulation of two-dimensional elastic wave propagation in functionally graded solids and structures. Gradient volume fractions of the constituent materials are assumed to ... [more ▼]

This contribution focuses on the simulation of two-dimensional elastic wave propagation in functionally graded solids and structures. Gradient volume fractions of the constituent materials are assumed to obey the power law function of position in only one direction and the effective mechanical properties of the material are determined by the Mori–Tanaka scheme. The investigations are carried out by extending a meshless method known as the Meshless Local Petrov-Galerkin (MLPG) method which is a truly meshless approach to thermo-elastic wave propagation. Simulations are carried out for rectangular domains under transient thermal loading. To investigate the effect of material composition on the dynamic response of functionally graded materials, a metal/ceramic (Aluminum (Al) and Alumina (Al2O3) are considered as ceramic and metal constituents) composite is considered for which the transient thermal field, dynamic displacement and stress fields are reported for different material distributions. [less ▲]

Detailed reference viewed: 57 (4 UL)
Full Text
Peer Reviewed
See detailAnalytical solutions to feedback systems on the special orthogonal group SO(n)
Markdahl, J.; Thunberg, Johan UL; Hoppe, J. et al

in the proceeding of the 52nd Annual Conference on Decision and Control (2013)

This paper provides analytical solutions to the closed-loop kinematics of two almost globally exponentially stabilizing attitude control laws on the special orthogonal group SO(n). By studying the general ... [more ▼]

This paper provides analytical solutions to the closed-loop kinematics of two almost globally exponentially stabilizing attitude control laws on the special orthogonal group SO(n). By studying the general case we give a uniform treatment to the cases of SO(2) and SO(3), which are the most interesting dimensions for application purposes. Working directly with rotation matrices in the case of SO(3) allows us to avoid certain complications which may arise when using local and global many-to-one parameterizations. The analytical solutions provide insight into the transient behaviour of the system and are of theoretical value since they can be used to prove almost global attractiveness of the identity matrix. The practical usefulness of analytical solutions in problems of continuous time actuation subject to piece-wise unavailable or discrete time sensing are illustrated by numerical examples. [less ▲]

Detailed reference viewed: 94 (3 UL)
Peer Reviewed
See detailAnalyzing the correlation between commuting satisfaction and travelling utility
Sprumont, François UL; Astegiano, Paola; Viti, Francesco UL

Scientific Conference (2016, July 13)

The interest for travel satisfaction has rapidly grown during the past two decades. Since the development of Discrete Choice Theory, doing a trip was mostly described as a pure derived activity without ... [more ▼]

The interest for travel satisfaction has rapidly grown during the past two decades. Since the development of Discrete Choice Theory, doing a trip was mostly described as a pure derived activity without utility per se but nowadays many scholars have demonstrated that individuals might be satisfied in performing the trip itself. However, little is still known on the relation between the travelling utility and the stated satisfaction for a specific trip. The objective of this paper is to analyse the relation between the stated commuting satisfaction and the utility of the associated trip thanks to the Logsum function, which is often used to represent the aggregated utility of a set of travel alternatives. The results of a travel survey implemented at the University of Luxembourg in 2012, show that the utility function, expressed through its Logsum, is positively correlated with the stated commuting satisfaction. While the Logsum function of the travelling utility might, to some extent, approximate the travelling satisfaction, some variations in the correlation magnitude, due to context particularities and socio-demographic attributes, are observed and discussed in this study. [less ▲]

Detailed reference viewed: 184 (9 UL)
Full Text
See detailAnticipation of brain shift in Deep Brain Stimulation automatic planning
Bilger, Alexandre UL; Cotin, Stephane; Duriez, Christian et al

in IEEE Engineering in Medicine and Biology Society (2015)

Deep Brain Stimulation is a neurosurgery procedure consisting in implanting an electrode in a deep structure of the brain. This intervention requires a preoperative planning phase, with a millimetric ... [more ▼]

Deep Brain Stimulation is a neurosurgery procedure consisting in implanting an electrode in a deep structure of the brain. This intervention requires a preoperative planning phase, with a millimetric accuracy, in which surgeons decide the best placement of the electrode depending on a set of surgical rules. However, brain tissues may deform during the surgery because of the brain shift phenomenon, leading the electrode to mistake the target, or moreover to damage a vital anatomical structure. In this paper, we present a patient-specific automatic planning approach for DBS procedures which accounts for brain deformation. Our approach couples an optimization algorithm with FEM based brain shift simulation. The system was tested successfully on a patient-specific 3D model, and was compared to a planning without considering brain shift. The obtained results point out the importance of performing planning in dynamic conditions. [less ▲]

Detailed reference viewed: 83 (1 UL)
Full Text
Peer Reviewed
See detailApplication of Design Models in Mechatronic Product Development and Building Design Reflection of Researchers and Practitioners
Eisenbart, Boris UL; Blessing, Lucienne UL

in Krause, Dieter, Paetzold, Kristin (Ed.) Beiträge zum 22. DfX-Symposium (2011)

Design models are an essential means for abstract representation and visualisation of information in the design process. Comprehension of design models in interdisciplinary engineering design teams is ... [more ▼]

Design models are an essential means for abstract representation and visualisation of information in the design process. Comprehension of design models in interdisciplinary engineering design teams is often hindered by different terminology and different discipline-specific modelling approaches. This paper presents the results of an interview study conducted with practitioners and researchers from engineering design and building design. The study elaborates the different ways of collaboration and use of design models in building design as compared to engineering design, in order to derive the potentials for cross-fertilisation between both areas of product development. [less ▲]

Detailed reference viewed: 104 (3 UL)
Full Text
Peer Reviewed
See detailAPPLICATION OF EXTENDED ELEMENT-FREE GALERKIN METHOD TO MULTIPLE FLAWS UNDER BRITTLE FRACTURE CONDITIONS
RABCZUK, T.; BEZENSEK, B.; Bordas, Stéphane UL

in PROCEEDINGS OF THE ASME PRESSURE VESSELS AND PIPING CONFERENCE - 2008, VOL 6, PT A AND B (2009)

The extended element-free Galerkin (XEFG) method incorporates cracks through partition of unity enrichment of the standard basis functions. Discontinuous functions are added to capture the jump through ... [more ▼]

The extended element-free Galerkin (XEFG) method incorporates cracks through partition of unity enrichment of the standard basis functions. Discontinuous functions are added to capture the jump through the crack faces and near-front enrichment is added to capture the asymptotic behaviour in the vicinity of the crack fronts. Depending on the material behaviour, these functions can be of various type. The method can treat initiation, growth and coalescence of cracks seamlessly in both linear elastic and non-linear settings. The method is a powerful tool for modelling and studying crack paths, which are a central feature in the assessment of multiple flaws.The method is applied to the problem of multiple non-aligned flaws in a ferritic plate under cleavage failure. Fracture paths from two nonaligned notches in a plate are modelled. Based on the observations of crack paths the critical flaw alignment distance is established for nonaligned through-wall flaws. [less ▲]

Detailed reference viewed: 99 (0 UL)
Full Text
Peer Reviewed
See detailApplication of robust model validation using SOSTOOLS to the study of G-Protein signalling in yeast
Yi, T.; Fazel, M.; Liu, X. et al

Scientific Conference (2005)

Two major methodological challenges in modeling biological systems are model (in)validation and parameter estimation. The traditional approach is to fit the model parameters to data. An alternative ... [more ▼]

Two major methodological challenges in modeling biological systems are model (in)validation and parameter estimation. The traditional approach is to fit the model parameters to data. An alternative approach pioneered by Packard, Frenklach, Seiler and colleagues (Frenklach et al., 2002) defines the range of parameter values that is consistent with the data while taking into account parametric and data uncertainty. If an invalidation certificate is found, the feasible parameter space is proved empty; otherwise, attempts to describe the feasible parameter space are carried out. We refer to this methodology as Robust Model Validation (RMV). Here we perform RMV using sum of squares (SOS) programs implemented by the MATLAB toolbox SOSTOOLS (Prajna et al., 2002). The principal advantage of SOS over conventional semidefinite programming (SDP) techniques such as the Sprocedure is the possibility of using higher-order multipliers to obtain tighter parameter bounds. We applied SOSTOOLS to a simple model of the yeast heterotrimeric G-protein cycle. We were able to invalidate the model based on real experimental data. Furthermore, using synthetic data that did not invalidate the model, we explored different techniques for representing the feasible parameter space. [less ▲]

Detailed reference viewed: 81 (1 UL)
Full Text
Peer Reviewed
See detailApplying dynamic Bayesian networks to perturbed gene expression data
Norbert, Dojer; Gambin, Anna; Mizera, Andrzej UL et al

in BMC Bioinformatics (2006), 7

Detailed reference viewed: 73 (6 UL)
Full Text
Peer Reviewed
See detailApplying synchronization in branch and trunk bus networks: an experimental analysis
Laskaris, Georgios; Rinaldi, Marco; Viti, Francesco UL

Scientific Conference (2021, June)

Detailed reference viewed: 15 (0 UL)
Full Text
Peer Reviewed
See detailAn approach to information retrieval and question answering in the legal domain
Adebayo, Kolawole John UL; Di Caro, Luigi; Boella, Guido et al

Scientific Conference (2016, November 15)

We describe in this paper, a report of our participation at COLIEE 2016 Information Retrieval (IR) and Legal Question Answering (LQA) tasks. Our solution for the IR part employs the use of a simple but ... [more ▼]

We describe in this paper, a report of our participation at COLIEE 2016 Information Retrieval (IR) and Legal Question Answering (LQA) tasks. Our solution for the IR part employs the use of a simple but effective Machine Learning (ML) procedure. Our Question Answering solution answers "YES or 'NO' to a question, i.e., 'YES' if the question is entailed by a text and 'NO' otherwise. With recent exploit of Multi-layered Neural Network systems at language modeling tasks, we presented a Deep Learning approach which uses an adaptive variant of the Long-Short Term Memory (LSTM), i.e. the Child Sum Tree LSTM (CST-LSTM) algorithm that we modified to suit our purpose. Additionally, we benchmarked this approach by handcrafting features for two popular ML algorithms, i.e., the Support Vector Machine (SVM) and the Random Forest (RF) algorithms. Even though we used some features that have performed well from similar works, we also introduced some semantic features for performance improvement. We used the results from these two algorithms as the baseline for our CST-LSTM algorithm. All evaluation was done on the COLIEE 2015 training and test sets. The overall result conforms the competitiveness of our approach. [less ▲]

Detailed reference viewed: 317 (12 UL)
Peer Reviewed
See detailApproche neuronale dynamique pour la prédiction de polluants atmosphériques: application à l'industrie papetière.
Sainlez, Matthieu UL; Heyen, Georges; Lumen, Philippe

Scientific Conference (2011, May 27)

Detailed reference viewed: 31 (2 UL)
Full Text
Peer Reviewed
See detailThe Arabidopsis circadian clock incorporates a cADPR-based feedback loop
Dodd, A. N.; Gardner, M. J.; Hotta, C. T. et al

in SCIENCE (2007), 318(5857), 1789-1792

Transcriptional feedback loops are a feature of circadian clocks in both animals and plants. We show that the plant circadian clock also incorporates the cytosolic signaling molecule cyclic adenosine ... [more ▼]

Transcriptional feedback loops are a feature of circadian clocks in both animals and plants. We show that the plant circadian clock also incorporates the cytosolic signaling molecule cyclic adenosine diphosphate ribose (cADPR). cADPR modulates the circadian oscillator’s transcriptional feedback loops and drives circadian oscillations of Ca2+ release. The effects of antagonists of cADPR signaling, manipulation of cADPR synthesis, and mathematical simulation of the interaction of cADPR with the circadian clock indicate that cADPR forms a feedback loop within the plant circadian clock. [less ▲]

Detailed reference viewed: 143 (14 UL)
Full Text
Peer Reviewed
See detailArchitecture tradeoffs of integrating a mesh generator to partition of unity enriched object-oriented finite element software
Dunant, C.; Nguyen, V. P.; Belgasmia, M. et al

in European Journal of Computational Mechanics (2007), 16(2), 237-258

We explore the tradeoffs of using an internal mesher in a XFEM code. We show that it allows an efficient enrichement detection scheme, while retaining the ability to have welladapted meshes. We provide ... [more ▼]

We explore the tradeoffs of using an internal mesher in a XFEM code. We show that it allows an efficient enrichement detection scheme, while retaining the ability to have welladapted meshes. We provide benchmarks highlighting the considerable gains which can be expected from a well designed architecture. The efficiency of the proposed algorithm is shown by solving fracture mechanics problems of densely micro-cracked bodies including adaptive mesh refinement. [less ▲]

Detailed reference viewed: 98 (0 UL)
Full Text
See detailARL – Akademie für RaumePostwachstum und Raumentwicklung – Denkanstöße für Wissenschaft und Praxis.
Best, Benjamin; Brückner, Heike; Hülz, Martina et al

Report (2021)

This position paper, drawn up by members of the ARL’s Working Group on Post-Growth Economies (2016 – 2020), situates the international post-growth debate and discusses its relevance for spatial ... [more ▼]

This position paper, drawn up by members of the ARL’s Working Group on Post-Growth Economies (2016 – 2020), situates the international post-growth debate and discusses its relevance for spatial development and spatial science research. In addition to sectoral approaches and findings, the authors make concrete proposals for post-growth focuses in planning, research and teaching, distinguishing between changes that can be achieved in the short term and measures designed for the medium to long term. [less ▲]

Detailed reference viewed: 66 (1 UL)
Full Text
Peer Reviewed
See detailAssessing geographical effects in spatial diffusion processes: The case of euro coins
Le Texier, Marion UL; Caruso, Geoffrey UL

in Computers, Environment and Urban Systems (2017), 61

We examine how geographical structures impact diffusion processes within a regional system. From the example of euro coin diffusion across countries, we show how the relative position and population ... [more ▼]

We examine how geographical structures impact diffusion processes within a regional system. From the example of euro coin diffusion across countries, we show how the relative position and population endowment of regions impact our understanding of interregional mobility, beyond simple spatial interaction effects. The mix of coins of different origins is a complex but unique trace of the movement of individuals within a common currency area, potentially revealing a new facet of European integration. We simulate an individual-based dynamic model where agents move and exchange coins across regions. We analyse the convergence towards a homogeneous mix of coins through time for a series of different theoretical spatial systems. This sensitivity analysis demonstrates the impact of the regularity and aggregation levels, or centrality/periphery effects, on spatial diffusion dynamics. We then calibrate the model against empirical data for the regions of 5 European countries and provide estimates of mobility rates, distance decay and population attractiveness factors, affecting the diffusion of coins, hence international movements and European integration. [less ▲]

Detailed reference viewed: 205 (9 UL)
Full Text
Peer Reviewed
See detailAssessing partial observability in network sensor location problems
Viti, Francesco UL; Rinaldi, Marco; Francesco, Corman et al

in Transportation Research. Part B : Methodological (2014), 70

The quality of information on a network is crucial for different transportation planning and management applications. Problems focusing on where to strategically extract this information can be broadly ... [more ▼]

The quality of information on a network is crucial for different transportation planning and management applications. Problems focusing on where to strategically extract this information can be broadly subdivided into observability problems, which rely on the topological properties of the network, and flow-estimation problems, where (prior) information on observed flows is needed to identify optimal sensor locations. This paper contributes mainly to the first category: more specifically, it presents a new methodology and an intuitive metric able to quantify the quality of a solution in case of partial observability, i.e. when not all flow variables are observed or can be uniquely determined from the observed flows. This methodology is based on existing approaches that can efficiently find solutions for full observability (i.e., the set of sensors needed to make the system fully determined), and exploits only the algebraic relations between link, route and origin-destination flow variables to quantify the information contained in any arbitrary subset of these variables. The new metric allows, through its adoption within simple search algorithms, to efficiently select sensor locations when the number of available sensors is limited by, for example, budget constraints and is less than the number needed to guarantee full observability. The chosen positions aim at selecting those locations that contain the largest information content on the whole network. This is an important contribution in this field, since even in small sized networks the solution for full observability requires an exceedingly large amount of sensors. The assessment of partial observability solutions, based on explicit route enumeration, allows one to categorize families of full observability solutions, and shows that these contain different information potential. This way, it is possible to rank solutions requiring a lower number of sensors while containing the same information content. We tested this new methodology both on toy networks, in order to analyse the properties of the metric and illustrate its logic, and to explain and test heuristic search algorithms for optimal sensor positioning on a real-sized network. Analysis of partial observability solutions shows that the basic search algorithms succeed in finding the links that contain the largest deal of information in a network. [less ▲]

Detailed reference viewed: 152 (8 UL)