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Analyzing the correlation between commuting satisfaction and travelling utility Sprumont, François ; ; Viti, Francesco 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: 156 (9 UL)Anticipation of brain shift in Deep Brain Stimulation automatic planning Bilger, Alexandre ; ; 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: 63 (1 UL)The apolitical aims of digital urban development: Following Alphabet Inc.'s waterfront development in Toronto. Hesse, Markus ; Carr, Constance Presentation (2019) Detailed reference viewed: 42 (1 UL)Application of Design Models in Mechatronic Product Development and Building Design Reflection of Researchers and Practitioners Eisenbart, Boris ; Blessing, Lucienne 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: 75 (3 UL)APPLICATION OF EXTENDED ELEMENT-FREE GALERKIN METHOD TO MULTIPLE FLAWS UNDER BRITTLE FRACTURE CONDITIONS ; ; Bordas, Stéphane 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: 75 (0 UL)Application of robust model validation using SOSTOOLS to the study of G-Protein signalling in yeast ; ; 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: 64 (1 UL)Applying dynamic Bayesian networks to perturbed gene expression data ; ; Mizera, Andrzej et al in BMC Bioinformatics (2006), 7 Detailed reference viewed: 57 (6 UL)An approach to information retrieval and question answering in the legal domain Adebayo, Kolawole John ; ; 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: 239 (12 UL)Approche neuronale dynamique pour la prédiction de polluants atmosphériques: application à l'industrie papetière. Sainlez, Matthieu ; ; Scientific Conference (2011, May 27) Detailed reference viewed: 26 (2 UL)The Arabidopsis circadian clock incorporates a cADPR-based feedback loop ; ; 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: 121 (14 UL)Architecture tradeoffs of integrating a mesh generator to partition of unity enriched object-oriented finite element software ; ; 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: 69 (0 UL)Assessing geographical effects in spatial diffusion processes: The case of euro coins Le Texier, Marion ; Caruso, Geoffrey in Computers, Environment & 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: 164 (8 UL)Assessing partial observability in network sensor location problems Viti, Francesco ; ; 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: 130 (8 UL)Assessing the consistency between observed and modelled route choices through GPS data ; ; Cantelmo, Guido et al in Proceedings of the MT-ITS Conference (2015, June) Detailed reference viewed: 88 (2 UL)Assessing the effect of route information on network observability applied to sensor location problems ; ; Viti, Francesco in Transportation Research Procedia (2015), 10 Detailed reference viewed: 87 (10 UL)Assessing the Performance of a Two-Step Dynamic Demand Estimation Model on Large-Scale Congested Networks Cantelmo, Guido ; Viti, Francesco Poster (2018, January) Detailed reference viewed: 119 (21 UL)Assessing the performance of coordinated predictive control strategies on urban-motorway networks Rinaldi, Marco ; Viti, Francesco in IFAC-PapersOnLine (2018, July), 51(9), 285-290 Coordination and integration of different traffic control policies have been of considerable interest in research in the last decades and, recently, have been object of large scale implementation trials ... [more ▼] Coordination and integration of different traffic control policies have been of considerable interest in research in the last decades and, recently, have been object of large scale implementation trials. In the setting of peri-urban motorway systems, coordination of various kinds of controllers must however be accompanied by accurate prediction of both propagation of flows and queues in the network, as well as the users’ response in terms of route choice. In this paper, we showcase through a real-life case study how coordination and prediction are both essential when performing hybrid urban-motorway control. Simulation results of a Model Predictive Control application are compared to simpler local control approaches, and the impact of coordinated intersection control and, additionally, Ramp Metering is evaluated. [less ▲] Detailed reference viewed: 60 (1 UL)Assessment of implicit and explicit algorithms in numerical simulation of granular matter Samiei, Kasra Doctoral thesis (2012) The objectives of this dissertation are to investigate and demonstrate the potentials of implicit integration methods in predicting the dynamics of granular media and to describe the granular dynamics on ... [more ▼] The objectives of this dissertation are to investigate and demonstrate the potentials of implicit integration methods in predicting the dynamics of granular media and to describe the granular dynamics on forward and backward acting grates by discrete element method. Traditionally, explicit integration methods are employed within the context of Discrete Element Method. Generally, explicit equations are simpler to solve than the implicit ones but they require a small time step to be utilized. In this study, an implicit Numerov integration scheme is employed to integrate the equations of motion. The implicit method is verified in different test cases starting from simple cases to more complicated cases including hundreds of particles. Comparing the results with the results of the explicit method, it is shown that the implicit method exhibits a distinguished advantage only at very large time steps. Taking into account the overhead of solving non-linear equations at each time step, it is concluded that implicit methods are computationally too expensive for their limited gains. Addressing the second objective of this study, the residence time distribution of granular particles on forward and backward acting grates are numerically predicted. Very good agreement between the predictions and the available experimental results is achieved. It can be concluded that the Discrete Element Method is highly capable of predicting the dynamics of solid fuel particles on grate systems. Future work shall include coupling of the method with computational fluid dynamics in order to account for thermal conversion of the fuel particles. [less ▲] Detailed reference viewed: 153 (4 UL)Attack-tolerant Control and Observer-based Trajectory Tracking for Cyber-Physical Systems Bezzaoucha, Souad ; Voos, Holger ; in European Journal of Control (2018) In the present paper, a model-based fault/attack tolerant scheme is proposed to cope with cyber-threats on Cyber-Physicals Systems. A common scheme based on observers is designed and a state feedback ... [more ▼] In the present paper, a model-based fault/attack tolerant scheme is proposed to cope with cyber-threats on Cyber-Physicals Systems. A common scheme based on observers is designed and a state feedback control based on an aperiodic event-triggered framework is given with control synthesis and condition on the switching time. Classical fault tolerant control with Bi-linear Matrix Inequality () approaches are used to achieve novel and better security strategy based on an event-triggered control implementation. The purpose of using the event-based implementation would be to reduce (limit) the total number of transmissions to only instances when the networked control system (NCS) needs attention. Simulation results on a real-time laboratory three tank system are given to show the attack-tolerant control ability despite data deception attacks on both actuators and sensors. A detection/isolation scheme based on residual observers bank is also proposed. [less ▲] Detailed reference viewed: 271 (6 UL)Attitude consensus using networks of uncalibrated cameras Thunberg, Johan ; in The proceedings of the 33rd Chinese Control Conference (2014) This paper addresses the problem of consensus on SO(3) for networks of uncalibrated cameras. Under the assumption of a pinhole camera model, we prove convergence to the consensus manifold for two types of ... [more ▼] This paper addresses the problem of consensus on SO(3) for networks of uncalibrated cameras. Under the assumption of a pinhole camera model, we prove convergence to the consensus manifold for two types of kinematic control laws, when only conjugate rotation matrices KRK-1 are available among the agents. In these conjugate rotations, the rotation matrices are distorted by the (unknown) intrinsic parameters of the cameras. For the conjugate rotations, we introduce distorted versions of well known local parameterizations of SO(3) and show consensus by using three types of control laws. The control laws are similar to the standard consensus protocol used for systems of agents with single integrator dynamics, where pairwise differences between the states of neighboring agents are used. By considering the restriction to the planar case (when all the rotations have the same rotational axes), we weaken the assumptions on the cameras in the system and consider networks where the camera matrices differ between agents. [less ▲] Detailed reference viewed: 73 (0 UL) |
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