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See detailIterative design of mobile learning systems for school projects
Melzer, André UL; Hadley, L.; Glasemann, M. et al

in Technology, Instruction, Cognition & Learning (2009), 6(4), 235-251

Different approaches have been proposed on the design and development of digital and interactive technology in mobile learning contexts. In line with recent findings in literature, we suggest that mobile ... [more ▼]

Different approaches have been proposed on the design and development of digital and interactive technology in mobile learning contexts. In line with recent findings in literature, we suggest that mobile learning systems benefit from a criteria-based iterative design and development process that incorporates evaluation results of mobile learning scenarios based on school curricula. Underlying these scenarios is a holistic, socio-technical system view, which makes allowance for the complex dynamics between teachers, students, researchers, the multiplicity of contextual factors, and the specifications and requirements of the digital devices and applications, as well as their interrelations. Five school project scenarios are described, as well as the evaluation process involved that served as an integral part in creating a dynamic optimization process for the design and development of digital and interactive systems that follow efficiency criteria for mobile learning (i.e., construction, contextualization, communication, and control). In addition, we argue that mobile systems should also allow for users’ or students’ participatory activities in the preparation phase to bridge the gap between indoor and outdoor learning. [less ▲]

Detailed reference viewed: 51 (1 UL)
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See detailAn iterative economic residential choice ABM of urban growth in Luxembourg (extended abstract)
Caruso, Geoffrey UL; Medard de Chardon, Cyrille UL

in Pinto N (Ed.) Proceedings of the Symposium on Cellular Automata Models of Urban and Spatial Systems (2012)

Detailed reference viewed: 54 (8 UL)
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See detailAn iterative learning approach for anticipatory traffic signal control on urban networks
Huang, Wei; Viti, Francesco UL; Tampere, Chris

in Transportmetrica B: Transport Dynamics (2016)

Detailed reference viewed: 126 (6 UL)
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See detailAn iterative learning approach for anticipatory traffic signal control on urban networks
Huang, Wei; Viti, Francesco UL; Tampere, Chris

in Transportmetrica B: Transport Dynamics (2017), 5(4), 407-430

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See detailAn Iterative Learning Approach for Signal Control in Urban Traffic Networks
Huang, Wei; Viti, Francesco UL; Tampere, Chris M.J.

in Proceedings of IEEE-ITS Conference (2013)

Traffic signal control influences route choice in traffic networks, and may even determine whether a traffic system settles in equilibrium or destabilizes into oscillatory patterns. Ideally, a stable ... [more ▼]

Traffic signal control influences route choice in traffic networks, and may even determine whether a traffic system settles in equilibrium or destabilizes into oscillatory patterns. Ideally, a stable equilibrium flow pattern should result from the interaction between control and route choice on a long-term horizon. This paper proposes an iterative learning approach for designing signal controls able to attract the system to equilibrium in an acceptable convergence speed. The traffic assignment model and combined traffic assignment and control problem are first introduced. An iterative learning control (ILC) based signal control is formulated and a basic model inversion method is analyzed. To deal with the nonlinearity of traffic system, a Newton based ILC algorithm is applied. Test in an example network verifies the effectiveness of the ILC method in achieving stable equilibrium in the traffic system. [less ▲]

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See detailAn iterative Mixed Integer Linear Programming Approach to pursuit evasion problems in polygonal environments
Thunberg, Johan UL; Ögren, P.

in Proceedings of the 2010 IEEE International Conference on Robotics and Automation (ICRA) (2010)

In this paper, we address the multi pursuer version of the pursuit evasion problem in polygonal environments. It is well known that this problem is NP-hard, and therefore we seek efficient, but not ... [more ▼]

In this paper, we address the multi pursuer version of the pursuit evasion problem in polygonal environments. It is well known that this problem is NP-hard, and therefore we seek efficient, but not optimal, solutions by relaxing the problem and applying the tools of Mixed Integer Linear Programming (MILP) and Receding Horizon Control (RHC). Approaches using MILP and RHC are known to produce efficient algorithms in other path planning domains, such as obstacle avoidance. Here we show how the MILP formalism can be used in a pursuit evasion setting to capture the motion of the pursuers as well as the partitioning of the pursuit search region into a cleared and a contaminated part. RHC is furthermore a well known way of balancing performance and computation requirements by iteratively solving path planning problems over a receding planning horizon, and adapt the length of that horizon to the computational resources available. The proposed approach is implemented in Matlab/Cplex and illustrated by a number of solved examples. [less ▲]

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See detailIterative observer-based state and parameter estimation for linear systems
Aalto, Atte UL

in ESAIM: Control, Optimisation and Calculus of Variations (2018), 24(1), 265-288

We propose an iterative method for joint state and parameter estimation using measurements on a time interval [0,T] for systems that are backward output stabilizable. Since this time interval is fixed ... [more ▼]

We propose an iterative method for joint state and parameter estimation using measurements on a time interval [0,T] for systems that are backward output stabilizable. Since this time interval is fixed, errors in initial state may have a big impact on the parameter estimate. We propose to use the back and forth nudging (BFN) method for estimating the system’s initial state and a Gauss–Newton step between BFN iterations for estimating the system parameters. Taking advantage of results on the optimality of the BFN method, we show that for systems with skew-adjoint generators, the initial state and parameter estimate minimizing an output error cost functional is an attractive fixed point for the proposed method. We treat both linear source estimation and bilinear parameter estimation problems. [less ▲]

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See detailIterative optimization for adaptive anticipatory control in urban traffic networks
Huang, Wei; Viti, Francesco UL; Tampere, Chris M.J.

Scientific Conference (2015, July)

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See detailIterative Precoder Design and User Scheduling for Block-Diagonalized Systems
Tran, Le-Nam; Bengtsson, Mats; Ottersten, Björn UL

in IEEE Transactions on Signal Processing (2012), 60(7), 3726-3739

The block diagonalization (BD) scheme is a low-complexity suboptimal precoding technique for multiuser multiple input-multiple output (MIMO) downlink channels, which completely precancels the multiuser ... [more ▼]

The block diagonalization (BD) scheme is a low-complexity suboptimal precoding technique for multiuser multiple input-multiple output (MIMO) downlink channels, which completely precancels the multiuser interference. Accordingly, the precoder of each user lies in the null space of other users' channel matrices. In this paper, we propose an iterative algorithm using QR decompositions (QRDs) to compute the precoders. Specifically, to avoid dealing with a large concatenated matrix, we apply the QRD to a sequence of matrices of lower dimensions. One problem of BD schemes is that the number of users that can be simultaneously supported is limited due to zero interference constraints. When the number of users is large, a set of users must be selected, and selection algorithms should be designed to exploit the multiuser diversity gain. Finding the optimal set of users requires an exhaustive search, which has too high computational complexity to be practically useful. Based on the iterative precoder design, this paper proposes a low-complexity user selection algorithm using a greedy method, in which the precoders of selected users are recursively updated after each selection step. The selection metric of the proposed scheduling algorithm relies on the product of the squared row norms of the effective channel matrices, which is related to the eigenvalues by the Hadamard and Schur inequalities. An asymptotic analysis is provided to show that the proposed algorithm can achieve the optimal sum rate scaling of the MIMO broadcast channel. The numerical results show that the proposed algorithm achieves a good trade-off between sum rate performance and computational complexity. When users suffer different channel conditions, providing fairness among users is of critical importance. To address this problem, we also propose two fair scheduling (FS) algorithms, one imposing fairness in the approximation of the data rate, and another directly imposing fairness in the product of the sq- ared row norms of the effective channel matrices. [less ▲]

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See detailAn Iterative Projection method for Synchronization of Invertible Matrices Over Graphs
Thunberg, Johan UL; Colombo, Nicolo UL; Yue, Zuogong UL et al

in 22nd International Symposium on Mathematical Theory of Networks and Systems (2016)

This paper addresses synchronization of invertible matrices over graphs. The matrices represent pairwise transformations between n euclidean coordinate systems. Synchronization means that composite ... [more ▼]

This paper addresses synchronization of invertible matrices over graphs. The matrices represent pairwise transformations between n euclidean coordinate systems. Synchronization means that composite transformations over loops are equal to the identity. Given a set of measured matrices that are not synchronized, the synchronization problem amounts to fining new synchronized matrices close to the former. Under the assumption that the measurement noise is zero mean Gaussian with known covariance, we introduce an iterative method based on linear subspace projection. The method is free of step size determination and tuning and numerical simulations show significant improvement of the solution compared to a recently proposed direct method as well as the Gauss-Newton method. [less ▲]

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See detailAn iterative technique for bounding derivatives of solutions of Stein equations
Döbler, Christian UL; Gaunt, Robert E.; Vollmer, Sebastian J.

in Electronic Journal of Probability (2017), 22

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See detailItinéraires croisés. Luxembourgeois à l'étranger, étrangers au Luxembourg
Reuter, Antoinette; Scuto, Denis UL

Book published by Editions Le Phare (1995)

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See detailItinéraires et présences de souverains en Lotharingie (Ca. 850-ca.950). Questions sur la place de la région mosane
Pettiau, Hérold UL

Presentation (2011, September 12)

This paper was given at a one-day workshop organised at the "Musée de l'Ardenne" in Charleville-Mézière (France) as part of a contribution made to an international research project dealing with the ... [more ▼]

This paper was given at a one-day workshop organised at the "Musée de l'Ardenne" in Charleville-Mézière (France) as part of a contribution made to an international research project dealing with the Ardenne as a frontier-region in the early Middle Ages. As a part of an ongoing research on itineraries of Carolingian [less ▲]

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See detailItinéraires luxembourgeois et européens.Evolutions et souvenirs: 1945-1985
Werner, Pierre; Danescu, Elena UL; Danescu, Elena UL

Book published by Gnosis - 2nd edition (2004)

Detailed reference viewed: 72 (2 UL)
See detailItinéraires luxembourgeois et européens.Evolutions et souvenirs: 1945-1985
Werner, Pierre; Danescu, Elena UL; Danescu, Elena UL

Book published by Gnosis - 1st edition (1998)

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See detailItinéraires luxembourgeois et européens.Evolutions et souvenirs: 1945-1985
Werner, Pierre; Danescu, Elena UL; Danescu, Elena UL

Book published by GNOSIS - 3th edition. Fully revised and corrected edition (2010)

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See detailItô's and Tanaka's type formulae for the stochastic heat equation: the linear case
Gradinaru, Mihai; Nourdin, Ivan UL; Tindel, Samy

in Journal of Functional Analysis (2005), 228(1), 114-143

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See detailIto's formula for Walsh's Brownian motion and applications
Hajri, Hatem UL; Touhami, Wajdi

in Statistics & Probability Letters (2014)

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See detailAn Itô's type formula for the fractional Brownian motion in Brownian time
Nourdin, Ivan UL; Zeineddine, Raghid

in Electronic Journal of Probability (2014), 19(99), 1-15

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See detailThe ITU Facing the Emergence of the Internet, 1960s–Early 2000s
Schafer, Valerie UL

in Fickers, Andreas; Balbi, Gabriele (Eds.) History of the International Telecommunication Union (ITU) (2020)

The development of data networks was based on the technical convergence of two worlds in the 1960s: telecommunications and computing. The ITU was thereby involved early on through the Consultative ... [more ▼]

The development of data networks was based on the technical convergence of two worlds in the 1960s: telecommunications and computing. The ITU was thereby involved early on through the Consultative Committee for International Telephony and Telegraphy (CCITT, now known as ITU- T) in the debates concerning transport protocols that arose from the 1970s. At the CCITT, telecommunications’ representatives decided in favour of virtual circuits, which enjoyed a long lifespan. Nevertheless, this choice diverged from the one made by the Arpanet’s researchers, and later the Internet’s community. Faced by the success of Internet and a new model of technical decisions and governance arising within the Internet community, which was openly divergent from the standardization previously at work, the ITU generated strong criticism at the end of the 1990s and at the beginning of the 2000s when it tried to enter the Internet field. The ITU then sought to restore its techno-diplomatic role through multi-stakeholderism, of which the World Summit on the Information Society (2003 and 2005) marked a crucial step. By crossing organizational archives, CCITT and ITU reports, oral history, press materials and web archives, this chapter will show how the ITU dealt with the transition from a well-recognized and salient techno-diplomatic role - partly due to the telecommunications’ monopolies- to a more peripheral position during the deregulation and the growth of the Internet. [less ▲]

Detailed reference viewed: 69 (1 UL)