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See detailDynamic pricing using wavelet neural network under uncertain demands
Sadegh AmalNick, Mohsen; Qorbanian, Roozbeh UL

in Decision Science Letters (2017)

Detailed reference viewed: 188 (2 UL)
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See detailDynamic problem solving competency: More than intelligence?
Wüstenberg, Sascha UL; Greiff, Samuel UL; Funke, Joachim

Scientific Conference (2011, July 05)

Detailed reference viewed: 58 (1 UL)
See detailDynamic Problem Solving in large-scale assessments: Perspectives
Greiff, Samuel UL

Presentation (2010, February 09)

Detailed reference viewed: 40 (1 UL)
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See detailDynamic problem solving. Multiple-item testing based on minimal complex systems.
Funke, Joachim; Greiff, Samuel UL

in Leutner, Detlev; Fleischer, Jens; Grünkorn, Jiliane (Eds.) et al Competence assessment in education : Research, models, and instruments. (2017)

Detailed reference viewed: 58 (2 UL)
See detailDynamic Problem Solving: A new computer-based perspective for large-scale assessments
Greiff, Samuel UL; Funke, Joachim

Scientific Conference (2011, March 30)

Detailed reference viewed: 36 (1 UL)
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See detailDynamic Problem Solving: A new measurement perspective
Greiff, Samuel UL; Wüstenberg, Sascha UL; Funke, Joachim

in Applied Psychological Measurement (2012), 36

This article addresses two unsolved measurement issues in dynamic problem solving (DPS) research: (a) unsystematic construction of DPS tests making a comparison of results obtained in different studies ... [more ▼]

This article addresses two unsolved measurement issues in dynamic problem solving (DPS) research: (a) unsystematic construction of DPS tests making a comparison of results obtained in different studies difficult and (b) use of time-intensive single tasks leading to severe reliability problems. To solve these issues, the MicroDYN approach is presented, which combines (a) the formal framework of linear structural equation models as a systematic way to construct tasks with (b) multiple and independent tasks to increase reliability. Results indicated that the assumed measurement model that comprised three dimensions, information retrieval, model building, and forecasting, fitted the data well (n = 114 students) and could be replicated in another sample (n = 140), showing excellent reliability estimates for all dimensions. Predictive validity of school grades was excellent for model building but nonexistent for the other two MicroDYN dimensions and for an additional measure of DPS. Implications are discussed. [less ▲]

Detailed reference viewed: 354 (148 UL)
See detailDynamic Problem Solving: A New Perspective for Large-scale Assessments
Greiff, Samuel UL; Wüstenberg, Sascha UL; Funke, Joachim

Scientific Conference (2010, April 14)

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See detailDynamic problem solving: Just intelligence or something different?
Wüstenberg, Sascha UL; Greiff, Samuel UL; Funke, Joachim

Scientific Conference (2011, September)

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See detailDynamic protonation equilibrium of solvated acetic acid
Gu, Wei UL; Frigato, Tomaso; Straatsma, Tjerk P. et al

in Angewandte Chemie International Edition (2007), 46(16), 2939-2943

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See detailDynamic qualitative filtering for linked (geo)visualisations: a prototype for exploring the collective memory of Instagram posts
Jones, Catherine UL; Guido, Daniele UL; Severo, Marta

Scientific Conference (2017, April 20)

This paper describes a prototype geo extension to an open source graph-based tool designed for analysing co-occurrence in large multimedia collections of historical resources. Employing an ... [more ▼]

This paper describes a prototype geo extension to an open source graph-based tool designed for analysing co-occurrence in large multimedia collections of historical resources. Employing an interdisciplinary approach, combining tools and practices from humanities and geography, we explore how it can be extended to facilitate both social and spatial enquiry. For the prototype development we use Instagram resources that reference the Via Francigena – a significant cultural route connecting Canterbury, UK and Rome, Italy. The resulting tool facilitates dynamic qualitative filtering and multilevel views to explore the social-spatial collective memory of this cultural route [less ▲]

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See detailDynamic regulation of microRNA expression following interferonγ- induced gene transcription
Reinsbach, Susanne UL; Nazarov, Petr V.; Philippidou, Demetra UL et al

in RNA Biology (2012), 9(7), 987-989

MicroRNAs are major players in post-transcriptional gene regulation. Even small changes in miRNA levels may have profound consequences for the expression levels of target genes. Hence, miRNAs themselves ... [more ▼]

MicroRNAs are major players in post-transcriptional gene regulation. Even small changes in miRNA levels may have profound consequences for the expression levels of target genes. Hence, miRNAs themselves need to be tightly, albeit dynamically, regulated. Here, we investigated the dynamic behavior of miRNAs over a wide time range following stimulation of melanoma cells with interferonγ (IFNγ), which activates the transcription factor STAT1. By applying several bioinformatic and statistical software tools for visualization and identification of differentially expressed miRNAs derived from time-series microarray experiments, 8.9% of 1105 miRNAs appeared to be directly or indirectly regulated by STAT1. Focusing on distinct dynamic expression patterns, we found that the majority of robust miRNA expression changes occurred in the intermediate time range (24-48 h). Three miRNAs (miR-27a, miR-30a and miR-34a) had a delayed regulation occurring at 72 h while none showed significant expression changes at early time points between 30 min and 6 h. Expression patterns of individual miRNAs were altered gradually over time or abruptly increased or decreased between two time points. Furthermore, we observed coordinated dynamic transcription of most miRNA clusters while few were found to be regulated independently of their genetic cluster. Most interestingly, several "star" or passenger strand sequences were specifically regulated over time while their "guide" strands were not. © 2012 Landes Bioscience. [less ▲]

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See detailDynamic Resource Allocation for Full-Duplex OFDMA Wireless Cellular Networks
Tran, Tam Thanh; Ha, Vu Nguyen UL; Le, Long Bao et al

in 2016 IEEE 84th Vehicular Technology Conference (VTC-Fall) proceedings (2016, September 18)

This paper focuses on the resource allocation in a full-duplex (FD) multiuser single cell system consisting of one FD base-station (BS) and multiple FD mobile nodes. In particular, we are interested in ... [more ▼]

This paper focuses on the resource allocation in a full-duplex (FD) multiuser single cell system consisting of one FD base-station (BS) and multiple FD mobile nodes. In particular, we are interested in jointly optimizing the power allocation (PA) and subcarrier assignment (SA) for uplink (UL) and downlink (DL) transmission of all users to maximize the system sum-rate. First, the joint optimization problem is formulated as nonconvex mixed integer program, a difficult nonconvex problem. We then propose an iterative algorithm to solve this problem. In the proposed algorithm, the PA is obtained by employing the SCALE algorithm, whereas the SA is updated by a gradient method. Finally, we present numerical results to demonstrate the significant gains of our proposed design compared to that due to two fast greedy algorithms. [less ▲]

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See detailDynamic response functions and helical gaps in interacting Rashba nanowires with and without magnetic fields
Pedder, Christopher UL; Meng, Tobias; Tiwari, Rakesh et al

in Physical Review B (2016), 94(24), 245414

A partially gapped spectrum due to the application of a magnetic field is one of the main probes of Rashba spin-orbit coupling in nanowires. Such a ``helical gap'' manifests itself in the linear ... [more ▼]

A partially gapped spectrum due to the application of a magnetic field is one of the main probes of Rashba spin-orbit coupling in nanowires. Such a ``helical gap'' manifests itself in the linear conductance, as well as in dynamic response functions such as the spectral function, the structure factor, or the tunnelling density of states. In this paper, we investigate theoretically the signature of the helical gap in these observables with a particular focus on the interplay between Rashba spin-orbit coupling and electron-electron interactions. We show that in a quasi-one-dimensional wire, interactions can open a helical gap even without magnetic field. We calculate the dynamic response functions using bosonization, a renormalization group analysis, and the exact form factors of the emerging sine-Gordon model. For special interaction strengths, we verify our results by refermionization. We show how the two types of helical gaps, caused by magnetic fields or interactions, can be distinguished in experiments. [less ▲]

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See detailDynamic RF Chain Selection for Energy Efficient and Low Complexity Hybrid Beamforming in Millimeter Wave MIMO Systems
Kaushik, Aryan; Thompson, John; Vlachos, Evangelos et al

in IEEE Transactions on Green Communications and Networking (2019)

This paper proposes a novel architecture with a framework that dynamically activates the optimal number of radio frequency (RF) chains used to implement hybrid beamforming in a millimeter wave (mmWave ... [more ▼]

This paper proposes a novel architecture with a framework that dynamically activates the optimal number of radio frequency (RF) chains used to implement hybrid beamforming in a millimeter wave (mmWave) multiple-input and multiple-output (MIMO) system. We use fractional programming to solve an energy efficiency maximization problem and exploit the Dinkelbach method (DM)-based framework to optimize the number of active RF chains and data streams. This solution is updated dynamically based on the current channel conditions, where the analog/digital (A/D) hybrid precoder and combiner matrices at the transmitter and the receiver, respectively, are designed using a codebook-based fast approximation solution called gradient pursuit (GP). The GP algorithm shows less run time and complexity while compared to the state-of-the-art orthogonal matching pursuit (OMP) solution. The energy and spectral efficiency performance of the proposed framework is compared with the existing state-of-the-art solutions, such as the brute force (BF), the digital beamformer, and the analog beamformer. The codebook-free approaches to design the precoders and combiners, such as alternating direction method of multipliers (ADMMs) and singular value decomposition (SVD)-based solution are also shown to be incorporated into the proposed framework to achieve better energy efficiency performance. [less ▲]

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See detailDynamic Risk Analyses and Dependency-Aware Root Cause Model for Critical Infrastructures
Muller, Steve UL; Harpes, Carlo; Le Traon, Yves UL et al

in International Conference on Critical Information Infrastructures Security (2016)

Critical Infrastructures are known for their complexity and the strong interdependencies between the various components. As a result, cascading effects can have devastating consequences, while foreseeing ... [more ▼]

Critical Infrastructures are known for their complexity and the strong interdependencies between the various components. As a result, cascading effects can have devastating consequences, while foreseeing the overall impact of a particular incident is not straight-forward at all and goes beyond performing a simple risk analysis. This work presents a graph-based approach for conducting dynamic risk analyses, which are programmatically generated from a threat model and an inventory of assets. In contrast to traditional risk analyses, they can be kept automatically up-to-date and show the risk currently faced by a system in real-time. The concepts are applied to and validated in the context of the smart grid infrastructure currently being deployed in Luxembourg. [less ▲]

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See detailA dynamic route swapping and control algorithm that maximises network capacity accounting for node constraints and blocking back
Viti, Francesco UL; Huang, Wei; Smith, Mike

Scientific Conference (2016, July)

Detailed reference viewed: 56 (1 UL)
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See detailDynamic Sensory Probabilistic Maps for Mobile Robot Localization
Vlassis, Nikos UL; Papakonstantinou, G.; Tsanakas, P.

in Proc. IEEE/RSJ Int. Conf. on Intelligent Robots and Systems (1998)

Detailed reference viewed: 78 (0 UL)
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See detailDynamic simulations to develop a natural ventilation concept for an office building
Thewes, Andreas UL; Maas, Stefan UL; Scholzen, Frank UL et al

in 8th International Conference on System Simulation in Buildings (2010)

The Sustainability Group of the University of Luxembourg defined for their new buildings a maximum thermal end-energy of 14 kWh/(m3a) and an electricity consumption for HVAC and lighting below 6 kWh/(m3a ... [more ▼]

The Sustainability Group of the University of Luxembourg defined for their new buildings a maximum thermal end-energy of 14 kWh/(m3a) and an electricity consumption for HVAC and lighting below 6 kWh/(m3a). Therefore it was necessary to avoid active cooling loads and mechanical ventilation in the offices and small lecture rooms. The well insulated and air-tight façade, including special outside shading elements which were designed as a grid over the complete building envelope, was an essential given architectural element of the building. Therefore further external shading devices were not applicable. The only possibility to have an influence on solar gains was to optimize the window size, the glazing type and potentially an internal shading device. Furthermore, to prevent the risk of overheating during the summer period, it was necessary to reduce the internal gains from lighting and IT-equipment. Hence detailed dynamic simulations using TRNSYS and TRNFLOW were done to evaluate the thermal comfort without air-conditioning and mechanical ventilation. The effects of optimizations like a state-of-the-art lighting control system or a window-based night ventilation, as well as the influence of the effective thermal inertia of the building were analyzed. The assumed natural ventilation rates were calculated by combining TRNFLOW and TRNSYS simulations and by the software LESOCOOL. [less ▲]

Detailed reference viewed: 210 (8 UL)
See detailDynamic Sintering of a High Temperature Granular Material: Experiments and Simulations
Willivald, Carolin; Kabore, Brice Wendlassida UL; Szabó, Denes et al

Scientific Conference (2017, September 26)

Snow changes from a porous solid to a granular material during deformation with high strain rates. This transition occurs in many cases where snow is relevant to engineering problems (vehicle mobility ... [more ▼]

Snow changes from a porous solid to a granular material during deformation with high strain rates. This transition occurs in many cases where snow is relevant to engineering problems (vehicle mobility, avalanche formation and prevention, skiing etc.). For the description of the fast deformation of snow the discrete element method (DEM) is a valuable tool, as it is able to account for both states and the transition between them: the interaction of the loose and bonded particles. For the development of a physically relevant DEM snow model [1] we investigate experimentally along with simulations the basic processes of the granular behavior of snow. In the granular state, sintering plays an important role for the dynamics of the particles. Via sintering the high temperature ice particles (homologous temperature 0.95) bond together and change the structure and the physical properties of the material. This temperature dependent sintering process, which happens in the time range of milliseconds to hours, is in the focus of the present work. The fast sintering of ice in the range of milliseconds has scarcely been investigated. However, from sintering studies with ice cones (radius of 3 mm) we know, that the sintering force is closely related to the contact area of the particles [2]. As the contact area changes considerably for complicated shapes, exhibited by natural snow crystals, we consider different snow types (grain shape and size), besides ice beads as spherical model snow. The latter one is used to exclude shape effects and to directly compare experiments to simulations with spherical particles. To be able to take the effects of the grain shape into account and to examine sintering in the time range of interest (seconds), we perform angle of repose experiments and simulations. Snow is sieved to pile up on a flat base until an angle of equilibrium, the angle of repose, is formed. This angle increases with the sintering of the particles, but also with the inter-particle friction. To analyze the contribution of the friction and the grain shape without sintering, we perform the experiments at a low temperature °C ( 0.87), where sintering can be neglected; thus, the angle of repose is determined by inter-particle friction. With these measurements, we calibrate the simulations. At higher temperatures (up to °C) sintering changes the angle of repose, and a physically relevant sintering law for real snow is established in the simulations. [less ▲]

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See detailDynamic Spectrum Sharing in 5G Wireless Networks with Full-Duplex Technology: Recent Advances and Research Challenges
Sharma; Bogale; Le et al

in IEEE Communications Surveys and Tutorials (2017)

Detailed reference viewed: 241 (2 UL)