Showing papers by "Eindhoven University of Technology published in 2014"
TL;DR: The survey covers the different facets of concept drift in an integrated way to reflect on the existing scattered state of the art and aims at providing a comprehensive introduction to the concept drift adaptation for researchers, industry analysts, and practitioners.
Abstract: Concept drift primarily refers to an online supervised learning scenario when the relation between the input data and the target variable changes over time. Assuming a general knowledge of supervised learning in this article, we characterize adaptive learning processes; categorize existing strategies for handling concept drift; overview the most representative, distinct, and popular techniques and algorithms; discuss evaluation methodology of adaptive algorithms; and present a set of illustrative applications. The survey covers the different facets of concept drift in an integrated way to reflect on the existing scattered state of the art. Thus, it aims at providing a comprehensive introduction to the concept drift adaptation for researchers, industry analysts, and practitioners.
2,374 citations
TL;DR: In this paper, the authors discuss the main definitions and conceptualizations of burnout and work engagement used in the literature, and review the most important antecedents of work engagement by examining situational and individual predictors.
Abstract: Whereas burnout refers to a state of exhaustion and cynicism toward work, engagement is defined as a positive motivational state of vigor, dedication, and absorption. In this article, we discuss the main definitions and conceptualizations of both concepts used in the literature. In addition, we review the most important antecedents of burnout and work engagement by examining situational and individual predictors. We also review the possible consequences of burnout and engagement and integrate the research findings using job demands– resources theory. Although both burnout and work engagement are related to important job-related outcomes, burnout seems to be more strongly related to health outcomes, whereas work engagement is morestronglyrelatedtomotivationaloutcomes. Wediscussdaily and momentary fluctuations in burnout and work engagement as possibilities for future research.
1,344 citations
TL;DR: This work describes a class of energy storage materials that exploits the favourable chemical and electrochemical properties of a family of molecules known as quinones, and demonstrates a metal-free flow battery based on the redox chemistry of 9,10-anthraquinone-2,7-disulphonic acid.
Abstract: Flow batteries, in which the electro-active components are held in fluid form external to the battery itself, are attractive as a potential means for regulating the output of intermittent renewable sources of electricity; an aqueous flow battery based on inexpensive commodity chemicals is now reported that also has the virtue of enabling further improvement of battery performance through organic chemical design. Flow batteries differ from the conventional type in that the electro-active components of flow batteries are held in fluid form external to the battery itself, enabling such systems to store arbitrarily large amounts of energy. Flow batteries are therefore attractive as a potential means for regulating the output of intermittent sources of electricity such as wind or solar power. But an important limitation of most such systems is the abundance and cost of the electro-active materials. To overcome this limitation, Brian Huskinson and colleagues have developed an aqueous flow battery on the basis of inexpensive, non-metallic commodity chemicals, with the added advantage of enabling the tuning of key battery properties through chemical design. As the fraction of electricity generation from intermittent renewable sources—such as solar or wind—grows, the ability to store large amounts of electrical energy is of increasing importance. Solid-electrode batteries maintain discharge at peak power for far too short a time to fully regulate wind or solar power output1,2. In contrast, flow batteries can independently scale the power (electrode area) and energy (arbitrarily large storage volume) components of the system by maintaining all of the electro-active species in fluid form3,4,5. Wide-scale utilization of flow batteries is, however, limited by the abundance and cost of these materials, particularly those using redox-active metals and precious-metal electrocatalysts6,7. Here we describe a class of energy storage materials that exploits the favourable chemical and electrochemical properties of a family of molecules known as quinones. The example we demonstrate is a metal-free flow battery based on the redox chemistry of 9,10-anthraquinone-2,7-disulphonic acid (AQDS). AQDS undergoes extremely rapid and reversible two-electron two-proton reduction on a glassy carbon electrode in sulphuric acid. An aqueous flow battery with inexpensive carbon electrodes, combining the quinone/hydroquinone couple with the Br2/Br− redox couple, yields a peak galvanic power density exceeding 0.6 W cm−2 at 1.3 A cm−2. Cycling of this quinone–bromide flow battery showed >99 per cent storage capacity retention per cycle. The organic anthraquinone species can be synthesized from inexpensive commodity chemicals8. This organic approach permits tuning of important properties such as the reduction potential and solubility by adding functional groups: for example, we demonstrate that the addition of two hydroxy groups to AQDS increases the open circuit potential of the cell by 11% and we describe a pathway for further increases in cell voltage. The use of π-aromatic redox-active organic molecules instead of redox-active metals represents a new and promising direction for realizing massive electrical energy storage at greatly reduced cost.
1,194 citations
11 Feb 2014
TL;DR: In this paper, the authors outline the building blocks of the job demands-resources (JD-R) theory, a theory that has been inspired by job design and job stress theories.
Abstract: This chapter outlines the building blocks of the job demands–resources (JD-R) theory, a theory that has been inspired by job design and job stress theories. Whereas job design theories have often ignored the role of job stressors or demands, job stress models have largely ignored the motivating potential of job resources. JD-R theory combines the two research traditions, and explains how job demands and (job and personal) resources have unique and multiplicative effects on job stress and motivation. In addition, JD-R theory proposes reversed causal effects: whereas burned-out employees may create more job demands over time for themselves, engaged workers mobilize their own job resources to stay engaged. The chapter closes with a discussion of possible JD-R interventions.
958 citations
TL;DR: OpenML as discussed by the authors is a place for machine learning researchers to share and organize data in fine detail, so that they can work more effectively, be more visible, and collaborate with others to tackle harder problems.
Abstract: Many sciences have made significant breakthroughs by adopting online tools that help organize, structure and mine information that is too detailed to be printed in journals. In this paper, we introduce OpenML, a place for machine learning researchers to share and organize data in fine detail, so that they can work more effectively, be more visible, and collaborate with others to tackle harder problems. We discuss how OpenML relates to other examples of networked science and what benefits it brings for machine learning research, individual scientists, as well as students and practitioners.
855 citations
TL;DR: In this article, a variable proportion of isotropically prestretched chains that can break and dissipate energy before the material fails is introduced to increase the stiffness and toughness of brittle elastomers.
Abstract: Elastomers are widely used because of their large-strain reversible deformability. Most unfilled elastomers suffer from a poor mechanical strength, which limits their use. Using sacrificial bonds, we show how brittle, unfilled elastomers can be strongly reinforced in stiffness and toughness (up to 4 megapascals and 9 kilojoules per square meter) by introducing a variable proportion of isotropically prestretched chains that can break and dissipate energy before the material fails. Chemoluminescent cross-linking molecules, which emit light as they break, map in real time where and when many of these internal bonds break ahead of a propagating crack. The simple methodology that we use to introduce sacrificial bonds, combined with the mapping of where bonds break, has the potential to stimulate the development of new classes of unfilled tough elastomers and better molecular models of the fracture of soft materials.
759 citations
TL;DR: In this article, the authors addressed the mix design and properties assessment of Ultra-High Performance Fibre Reinforced Concrete (UHPFRC) by employing the modified Andreasen & Andersen particle packing model.
615 citations
TL;DR: A review of recent research on green road freight transportation is provided to provide an understanding of vehicle emission models and their inclusion into the existing optimization methods.
600 citations
TL;DR: In this paper, the authors provide a perspective on the past, present and future of Computational Wind Engineering (CWE) and provide a more detailed view on CFD simulation of pedestrian-level wind conditions around buildings.
570 citations
TL;DR: A review of the OR/MS literature on supply chain disruptions can be found in this paper, where the authors provide an overview of the research questions that have been addressed and a discussion of future research directions.
Abstract: We review the OR/MS literature on supply chain disruptions in order to take stock of the research to date and to provide an overview of the research questions that have been addressed. We first place disruptions in the context of other forms of supply uncertainty and discuss common modeling approaches. We then discuss nearly 150 scholarly works on the topic, organized into six categories: evaluating supply disruptions; strategic decisions; sourcing decisions; contracts and incentives; inventory; and facility location. We conclude with a discussion of future research directions.
553 citations
TL;DR: A novel definition for string stability of nonlinear cascaded systems is proposed, using input-output properties, and is shown to result in well-known string stability conditions for linear cascading systems.
Abstract: Nowadays, throughput has become a limiting factor in road transport. An effective means to increase the road throughput is to employ a small intervehicle time gap using automatic vehicle-following control systems. String stability, i.e., the disturbance attenuation along the vehicle string, is considered an essential requirement for the design of those systems. However, the formal notion of string stability is not unambiguous in literature, since both stability and performance interpretations exist. Therefore, a novel definition for string stability of nonlinear cascaded systems is proposed, using input-output properties. This definition is shown to result in well-known string stability conditions for linear cascaded systems. The theoretical results are experimentally validated using a platoon of six passenger vehicles equipped with cooperative adaptive cruise control.
TL;DR: The paper explains the concept of generic photonic integration technology using the technology developed by the COBRA research institute of TU Eindhoven as an example, and it describes the current status and prospects of generic InP-based integration technology.
Abstract: Photonic integrated circuits (PICs) are considered as the way to make photonic systems or subsystems cheap and ubiquitous. PICs still are several orders of magnitude more expensive than their microelectronic counterparts, which has restricted their application to a few niche markets. Recently, a novel approach in photonic integration is emerging which will reduce the R&D and prototyping costs and the throughput time of PICs by more than an order of magnitude. It will bring the application of PICs that integrate complex and advanced photonic functionality on a single chip within reach for a large number of small and larger companies and initiate a breakthrough in the application of Photonic ICs. The paper explains the concept of generic photonic integration technology using the technology developed by the COBRA research institute of TU Eindhoven as an example, and it describes the current status and prospects of generic InP-based integration technology.
TL;DR: The cumulative result is a series of tough hydrogels with tunable mechanical properties and tractable synthetic preparation and processing, in which the melting transition of PEG in the dry polymer was shown to be an effective stimulus for shape memory behavior.
Abstract: Hydrogels were prepared with physical cross-links comprising 2-ureido-4[1H]-pyrimidinone (UPy) hydrogen-bonding units within the backbone of segmented amphiphilic macromolecules having hydrophilic poly(ethylene glycol) (PEG). The bulk materials adopt nanoscopic physical cross-links composed of UPy–UPy dimers embedded in segregated hydrophobic domains dispersed within the PEG matrix as comfirmed by cryo-electron microscopy. The amphiphilic network was swollen with high weight fractions of water (wH2O ≈ 0.8) owing to the high PEG weight fraction within the pristine polymers (wPEG ≈ 0.9). Two different PEG chain lengths were investigated and illustrate the corresponding consequences of cross-link density on mechanical properties. The resulting hydrogels exhibited high strength and resilience upon deformation, consistent with a microphase separated network, in which the UPy–UPy interactions were adequately shielded within hydrophobic nanoscale pockets that maintain the network despite extensive water content....
TL;DR: In this article, the authors used probit estimation to identify the relationship between entrepreneurship education, prior entrepreneurial exposure, perceived desirability and feasibility, and entrepreneurial intentions (EI) for university students.
Abstract: Using Ajzen’s theory of planned behavior and Shapero’s entrepreneurial event model as well as entrepreneurial cognition theory, we attempt to identify the relationship between entrepreneurship education, prior entrepreneurial exposure, perceived desirability and feasibility, and entrepreneurial intentions (EI) for university students. The data were collected from a survey of ten universities; we received 494 effective responses. We used probit estimation to show that perceived desirability significantly impacts EI whereas there is no significant impact from perceived feasibility. There is a significant negative impact from exposure (which is surprising) and a significant positive impact from entrepreneurship education. Males and people from technological universities and/or backgrounds have higher EI than females and people from other universities and backgrounds. There are also significant positive interactive effects by gender, university type, and study major on the relationship between entrepreneurship education and EI.
Memorial Hermann Healthcare System1, University of Texas at Austin2, Utrecht University3, VU University Medical Center4, Nanjing Medical University5, University of Málaga6, Memorial Hospital of South Bend7, Odense University Hospital8, Gazi University9, Seoul National University Hospital10, New York University11, University of Lausanne12, Keimyung University13, French Institute of Health and Medical Research14, Laval University15, Fukushima Medical University16, Eindhoven University of Technology17, university of lille18, Ospedale di Circolo e Fondazione Macchi19, Stanford University20
TL;DR: FFR demonstrates a continuous and independent relationship with subsequent outcomes, modulated by medical therapy versus revascularization, such that lower FFR values confer a higher risk and therefore receive larger absolute benefits fromRevascularization.
TL;DR: In this article, registered reports of replications of important published results in social psychology are reported with strong confirmatory tests, and the articles demonstrate open science practices such as open data, open materials, and disclosure of research process, conflicts of interest, and contributions.
Abstract: Ignoring replications and negative results is bad for science. This special issue presents a novel publishing format – Registered Reports – as a partial solution. Peer review occurs prior to data collection, design and analysis plans are preregistered, and results are reported regardless of outcome. Fourteen Registered Reports of replications of important published results in social psychology are reported with strong confirmatory tests. Further, the articles demonstrate open science practices such as open data, open materials, and disclosure of research process, conflicts of interest, and contributions. The credibility of published science will increase with cultural shifts that accept replications and negative results as viable research outcomes, and when transparency and reproducibility are part of standard research practice.
TL;DR: In this article, the daily influence of transformational leadership, contingent reward, and active management-by-exception (MBE active) on followers' daily work engagement was examined.
Abstract: This diary study adds to the leadership literature by examining the daily influence of transformational leadership, contingent reward, and active management-by-exception (MBE active) on followers' daily work engagement. We compare the unique contribution of these leadership behaviours and focus on the work environment to examine how these leadership behaviours influence followers' daily work engagement. While travelling by sail ship, 61 naval cadets filled out a diary questionnaire for 34 days. Multilevel regression analyses revealed that, after controlling for followers' work engagement the previous day, cadets were more engaged on days that their leader showed more transformational leadership and provided contingent reward. MBE active was unrelated to followers' work engagement. As predicted, transformational leadership and contingent reward contributed to a more favourable work environment (more autonomy and support), while MBE active resulted in a less favourable work environment (less autonomy) for the cadets. This study highlights the importance of daily leadership for followers' daily work engagement.
TL;DR: The aim of the paper is to focus on the industrial aspects of scheduling and discuss the main characteristics, including strengths and weaknesses of the presented approaches, as well as some lessons learned from industry.
TL;DR: This work derives the thermodynamically consistent governing equations for the fourth-order phase-field model by way of a variational principle based on energy balance assumptions, which leads to higher regularity in the exact phase- field solution, which can be exploited by the smooth spline function spaces utilized in isogeometric analysis.
TL;DR: In this article, the authors demonstrate the viability of spatial multiplexing to reach a data rate of 5.1 Tbit/s−1/carrier−1 on a single wavelength over a single fiber, by employing few-mode multicore fiber, compact three-dimensional waveguide multiplexers and energy-efficient frequency-domain MIMO equalization.
Abstract: Single-mode fibres with low loss and a large transmission bandwidth are a key enabler for long-haul high-speed optical communication and form the backbone of our information-driven society. However, we are on the verge of reaching the fundamental limit of single-mode fibre transmission capacity. Therefore, a new means to increase the transmission capacity of optical fibre is essential to avoid a capacity crunch. Here, by employing few-mode multicore fibre, compact three-dimensional waveguide multiplexers and energy-efficient frequency-domain multiple-input multiple-output equalization, we demonstrate the viability of spatial multiplexing to reach a data rate of 5.1 Tbit s−1 carrier−1 (net 4 Tbit s−1 carrier−1) on a single wavelength over a single fibre. Furthermore, by combining this approach with wavelength division multiplexing with 50 wavelength carriers on a dense 50 GHz grid, a gross transmission throughput of 255 Tbit s−1 (net 200 Tbit s−1) over a 1 km fibre link is achieved. A few-mode, multicore fibre allows ultra-high-speed data transmission on a single wavelength of light.
TL;DR: In this article, a joint analysis of in-situ deformation experiments on two different dual phase (DP) steel grades was conducted using microscopic-digital image correlation (lDIC) techniques to achieve microstructural strain maps of representative statistics and high resolution.
TL;DR: In this article, the authors presented the effect of nano-silica on the hydration and microstructure development of UltraHigh Performance Concrete (UHPC) with a low binder amount.
TL;DR: A controller design method is developed that allows for explicit inclusion of the string stability requirement in the controller synthesis specifications, and L2 string-stable platooning strategies are obtained in both cases, revealing that the two-vehicle look-ahead topology is particularly effective at a larger communication delay.
Abstract: Cooperative adaptive cruise control (CACC) allows for short-distance automatic vehicle following using intervehicle wireless communication in addition to onboard sensors, thereby potentially improving road throughput. In order to fulfill performance, safety, and comfort requirements, a CACC-equipped vehicle platoon should be string stable, attenuating the effect of disturbances along the vehicle string. Therefore, a controller design method is developed that allows for explicit inclusion of the string stability requirement in the controller synthesis specifications. To this end, the notion of string stability is introduced first, and conditions for L2 string stability of linear systems are presented that motivate the development of an H∞ controller synthesis approach for string stability. The potential of this approach is illustrated by its application to the design of controllers for CACC for one- and two-vehicle look-ahead communication topologies. As a result, L2 string-stable platooning strategies are obtained in both cases, also revealing that the two-vehicle look-ahead topology is particularly effective at a larger communication delay. Finally, the results are experimentally validated using a platoon of three passenger vehicles, illustrating the practical feasibility of this approach.
TL;DR: An up-to-date overview of both technological and chemical aspects associated with photochemical processes in microreactors is provided and fundamental principles are deduced for making a judicious choice for a suitable photomicroreactor.
Abstract: Continuous-flow photochemistry is used increasingly by researchers in academia and industry to facilitate photochemical processes and their subsequent scale-up. However, without detailed knowledge concerning the engineering aspects of photochemistry, it can be quite challenging to develop a suitable photochemical microreactor for a given reaction. In this review, we provide an up-to-date overview of both technological and chemical aspects associated with photochemical processes in microreactors. Important design considerations, such as light sources, material selection, and solvent constraints are discussed. In addition, a detailed description of photon and mass-transfer phenomena in microreactors is made and fundamental principles are deduced for making a judicious choice for a suitable photomicroreactor. The advantages of microreactor technology for photochemistry are described for UV and visible-light driven photochemical processes and are compared with their batch counterparts. In addition, different scale-up strategies and limitations of continuous-flow microreactors are discussed.
TL;DR: It is shown that for several popular event-triggering mechanisms no positive minimum inter-event time can be guaranteed in the presence of arbitrary small external disturbances or measurement noise, and it is essential to include the effects of external disturbances and measurement noise in the analysis of the computation/communication properties of event-triggered control systems.
Abstract: In this paper, we study fundamental properties of minimum inter-event times for several event-triggered control architectures, both in the absence and presence of external disturbances and/or measurement noise. This analysis reveals, amongst others, that for several popular event-triggering mechanisms no positive minimum inter-event time can be guaranteed in the presence of arbitrary small external disturbances or measurement noise. This clearly shows that it is essential to include the effects of external disturbances and measurement noise in the analysis of the computation/communication properties of event-triggered control systems. In fact, this paper also identifies event-triggering mechanisms that do exhibit these important event-separation properties.
01 Aug 2014
TL;DR: Work on learning analytics that aims to support learners and teachers through dashboard applications, ranging from small mobile applications to learnscapes on large public displays, is presented, identifying HCI issues for this exciting research area.
Abstract: In this paper, we present work on learning analytics that aims to support learners and teachers through dashboard applications, ranging from small mobile applications to learnscapes on large public displays. Dashboards typically capture and visualize traces of learning activities, in order to promote awareness, reflection, and sense-making, and to enable learners to define goals and track progress toward these goals. Based on an analysis of our own work and a broad range of similar learning dashboards, we identify HCI issues for this exciting research area.
TL;DR: A simple one-pot, low-temperature polycondensation between paraformaldehyde and 4,4ʹ-oxydianiline (ODA) that forms hemiaminal dynamic covalent networks (HDCNs), which can further cyclize at high temperatures, producing poly(hexahydrotriazine)s (PHTs).
Abstract: Nitrogen-based thermoset polymers have many industrial applications (for example, in composites), but are difficult to recycle or rework. We report a simple one-pot, low-temperature polycondensation between paraformaldehyde and 4,4ʹ-oxydianiline (ODA) that forms hemiaminal dynamic covalent networks (HDCNs), which can further cyclize at high temperatures, producing poly(hexahydrotriazine)s (PHTs). Both materials are strong thermosetting polymers, and the PHTs exhibited very high Young’s moduli (up to ~14.0 gigapascals and up to 20 gigapascals when reinforced with surface-treated carbon nanotubes), excellent solvent resistance, and resistance to environmental stress cracking. However, both HDCNs and PHTs could be digested at low pH (
TL;DR: This research presents a novel and scalable approaches called “Smart Gene Regulation” that allows for real-time annotation of the FISH signal in the Eindhoven–Borff–Seiden cellular automaton.
Abstract: Lech-Gustav Milroy,† Tom N. Grossmann,‡,§ Sven Hennig,‡ Luc Brunsveld,† and Christian Ottmann*,† †Laboratory of Chemical Biology and Institute of Complex Molecular Systems, Department of Biomedical Engineering, Technische Universiteit Eindhoven, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands ‡Chemical Genomics Centre of the Max Planck Society, Otto-Hahn Straße 15, 44227 Dortmund, Germany Department of Chemistry and Chemical Biology, Technical University Dortmund, Otto-Hahn-Strasse 6, 44227 Dortmund, Germany
TL;DR: In this paper, a detailed analysis of the gas temperature determination from rotational spectra is performed, and a large range of conditions for which non-equilibrium occurs are identified.
Abstract: The gas temperature in non-equilibrium plasmas is often obtained from the plasma-induced emission by measuring the rotational temperature of a diatomic molecule in its excited state. This is motivated by both tradition and the availability of low budget spectrometers. However, non-thermal plasmas do not automatically guarantee that the rotational distribution in the monitored vibrational level of the diatomic molecule is in equilibrium with the translational (gas) temperature. Often non-Boltzmann rotational molecular spectra are found in non-equilibrium plasmas. The deduction of a gas temperature from these non-thermal distributions must be done with care as clearly the equilibrium between translational and rotational degrees of freedom cannot be achieved. In this contribution different methods and approaches to determine the gas temperature are evaluated and discussed. A detailed analysis of the gas temperature determination from rotational spectra is performed. The physical and chemical background of non-equilibrium rotational population distributions in molecular spectra is discussed and a large range of conditions for which non-equilibrium occurs are identified. Fitting procedures which are used to fit (non-equilibrium) rotational distributions are analyzed in detail. Lastly, recommendations concerning the conditions for which the gas temperatures can be obtained from diatomic spectra are formulated.
TL;DR: An adaptive large neighborhood search algorithm (ALNS), combined with a speed optimization procedure, to solve the bi-objective PRP and shows that HM is highly effective in finding good-quality non-dominated solutions on PRP instances with 100 nodes.