Showing papers by "Eindhoven University of Technology published in 2009"
TL;DR: In this paper, the authors investigate if open innovation practices are also applied by small and medium-sized enterprises (SMEs) and explore the incidence of and apparent trend towards open innovation.
1,947 citations
TL;DR: A literature review has been performed on the measurements of five key concepts in HRI: anthropomorphism, animacy, likeability, perceived intelligence, and perceived safety, distilled into five consistent questionnaires using semantic differential scales.
Abstract: This study emphasizes the need for standardized measurement tools for human robot interaction (HRI). If we are to make progress in this field then we must be able to compare the results from different studies. A literature review has been performed on the measurements of five key concepts in HRI: anthropomorphism, animacy, likeability, perceived intelligence, and perceived safety. The results have been distilled into five consistent questionnaires using semantic differential scales. We report reliability and validity indicators based on several empirical studies that used these questionnaires. It is our hope that these questionnaires can be used by robot developers to monitor their progress. Psychologists are invited to further develop the questionnaires by adding new concepts, and to conduct further validations where it appears necessary.
1,889 citations
TL;DR: This introductory review on plasma health care is intended to provide the interested reader with a summary of the current status of this emerging field, its scope, and its broad interdisciplinary approach, ranging from plasma physics, chemistry and technology, to microbiology, biochemistry, biophysics, medicine and hygiene.
Abstract: This introductory review on plasma health care is intended to provide the interested reader with a summary of the current status of this emerging field, its scope, and its broad interdisciplinary approach, ranging from plasma physics, chemistry and technology, to microbiology, biochemistry, biophysics, medicine and hygiene. Apart from the basic plasma processes and the restrictions and requirements set by international health standards, the review focuses on plasma interaction with prokaryotic cells (bacteria), eukaryotic cells (mammalian cells), cell membranes, DNA etc. In so doing, some of the unfamiliar terminology—an unavoidable by-product of interdisciplinary research—is covered and explained. Plasma health care may provide a fast and efficient new path for effective hospital (and other public buildings) hygiene— helping to prevent and contain diseases that are continuously gaining ground as resistance of pathogens to antibiotics grows. The delivery of medically active 'substances' at the molecular or ionic level is another exciting topic of research through effects on cell walls (permeabilization), cell excitation (paracrine action) and the introduction of reactive species into cell cytoplasm. Electric fields, charging of surfaces, current flows etc can also affect tissue in a controlled way. The field is young and hopes are high. It is fitting to cover the beginnings in New Journal of Physics, since it is the physics (and non- equilibrium chemistry) of room temperature atmospheric pressure plasmas that have made this development of plasma health care possible.
1,441 citations
TL;DR: In this article, a general experimental method to determine the energy ECT of intermolecular charge transfer (CT) states in electron donor-acceptor (D-A) blends from ground state absorption and electrochemical measurements is proposed.
Abstract: Here, a general experimental method to determine the energy ECT of intermolecular charge-transfer (CT) states in electron donor–acceptor (D–A) blends from ground state absorption and electrochemical measurements is proposed. This CT energy is calibrated against the photon energy of maximum CT luminescence from selected D–A blends to correct for a constant Coulombic term. It is shown that ECT correlates linearly with the open-circuit voltage (Voc) of photovoltaic devices in D–A blends via eVoc = ECT − 0.5 eV. Using the CT energy, it is found that photoinduced electron transfer (PET) from the lowest singlet excited state (S1 with energy Eg) in the blend to the CT state (S1 → CT) occurs when Eg − ECT > 0.1 eV. Additionally, it is shown that subsequent charge recombination from the CT state to the lowest triplet excited state (ET) of D or A (CT → T1) can occur when ECT − ET > 0.1 eV. From these relations, it is concluded that in D–A blends optimized for photovoltaic action: i) the maximum attainable Voc is ultimately set by the optical band gap (eVoc = Eg − 0.6 eV) and ii) the singlet–triplet energy gap should be ΔEST < 0.2 eV to prevent recombination to the triplet state. These favorable conditions have not yet been met in conjugated materials and set the stage for further developments in this area.
926 citations
TL;DR: It is demonstrated that all-polymer microdevices can be fabricated using inkjet printing technology in combination with self-organizing liquid-crystal network actuators, exploiting the self-assembling properties of the liquid crystal to create large strain gradients, and light-driven actuation is chosen to allow simple and remote addressing.
Abstract: Polymeric microactuators are potentially useful in micromechanical systems and lab-on-a-chip systems. However, manufacturing of miniature polymeric actuators has been complicated owing to the necessity of including electrodes for actuation or using lithographic techniques for patterning. Here, we demonstrate that all-polymer microdevices can be fabricated using inkjet printing technology in combination with self-organizing liquid-crystal network actuators. We exploit the self-assembling properties of the liquid crystal to create large strain gradients, and light-driven actuation is chosen to allow simple and remote addressing. By using multiple inks, microactuators with different subunits are created that can be selectively addressed by changing the wavelength of the light. The actuators mimic the motion of natural cilia. These artificial cilia have the potential to create flow and mixing in wet environments such as lab-on-a-chip applications. The process is easily adapted for roll-to-roll fabrication, allowing for large-scale and low-cost production of miniaturized active polymer systems.
837 citations
TL;DR: This Minireview discusses the success and applicability of new, in particular metal-free, click reactions, which expand the opportunities for synthesizing small organic compounds as well as tailor-made macromolecules and bioconjugates.
Abstract: No copper needed: In recent years, a large number of metal-free click reactions have been reported based on thiol-ene radical additions, Diels–Alder reactions, and Michael additions. In this Minireview, special attention is given to the advantages and limitations of the different methods to evaluate whether they have the potential to surpass the overwhelming success of the copper(I)-catalyzed azide-alkyne cycloaddition.
The overwhelming success of click chemistry encouraged researchers to develop alternative “spring-loaded” chemical reactions for use in different fields of chemistry. Initially, the copper(I)-catalyzed azide-alkyne cycloaddition was the only click reaction. In recent years, metal-free [3+2] cycloaddition reactions, Diels–Alder reactions, and thiol-alkene radical addition reactions have come to the fore as click reactions because of their simple synthetic procedures and high yields. Furthermore, these metal-free reactions have wide applicability and are physiologically compatible. These and other alternative click reactions expand the opportunities for synthesizing small organic compounds as well as tailor-made macromolecules and bioconjugates. This Minireview discusses the success and applicability of new, in particular metal-free, click reactions.
790 citations
TL;DR: Cryotransmission electron microscopy has found that template-directed calcium carbonate formation starts with the formation of prenucleation clusters, which aggregation leads to the nucleation of amorphous nanoparticles in solution.
Abstract: Biogenic calcium carbonate forms the inorganic component of seashells, otoliths, and many marine skeletons, and its formation is directed by an ordered template of macromolecules. Classical nucleation theory considers crystal formation to occur from a critical nucleus formed by the assembly of ions from solution. Using cryotransmission electron microscopy, we found that template-directed calcium carbonate formation starts with the formation of prenucleation clusters. Their aggregation leads to the nucleation of amorphous nanoparticles in solution. These nanoparticles assemble at the template and, after reaching a critical size, develop dynamic crystalline domains, one of which is selectively stabilized by the template. Our findings have implications for template-directed mineral formation in biological as well as in synthetic systems.
764 citations
TL;DR: A new semiconducting polymer, PDPP3T, with alternating diketopyrrolopyrrole and terthiophene units is presented and the efficiency of the photovoltaic cells was found to be strongly dependent on the molecular weight of PDPp3T and the use of diiodooctane as a processing agent.
Abstract: A new semiconducting polymer, PDPP3T, with alternating diketopyrrolopyrrole and terthiophene units is presented. PDPP3T has a small band gap of 1.3 eV and exhibits nearly balanced hole and electron mobilities of 0.04 and 0.01 cm2 V−1 s−1, respectively, in field-effect transistors (FETs). By the combination of two identical ambipolar transistors, an inverter was constructed that exhibits a gain of ∼30. When PDPP3T was combined with [60]PCBM or [70]PCBM in a 1:2 weight ratio, photovoltaic cells were made that provide a photoresponse up to 900 nm and an AM1.5 power conversion efficiency of 3.8 or 4.7%, respectively. In contrast to the almost constant FET mobility, the efficiency of the photovoltaic cells was found to be strongly dependent on the molecular weight of PDPP3T and the use of diiodooctane as a processing agent.
742 citations
TL;DR: In this paper, the basic strategies towards charged and non-charged iridium(III) complexes are summarized, and a wide range of assemblies are discussed, with special emphasis on the latter with respect to synthesis, characterization, electro-optical properties, processing technologies, and performance.
Abstract: The recent developments in using iridium(III) complexes as phosphorescent emitters in electroluminescent devices, such as (white) organic light-emitting diodes and light-emitting electrochemical cells, are discussed. Additionally, applications in the emerging fields of molecular sensors, biolabeling, and photocatalysis are briefly evaluated. The basic strategies towards charged and non-charged iridium(III) complexes are summarized, and a wide range of assemblies is discussed. Small-molecule- and polymer-based materials are under intense investigation as emissive systems in electroluminescent devices, and special emphasis is placed on the latter with respect to synthesis, characterization, electro-optical properties, processing technologies, and performance.
682 citations
TL;DR: In this paper, the effect of user behavior on building performance has been evaluated further to assess requirements for design solutions to arrive at buildings that are more robust to the influence of user behaviour.
614 citations
21 Jul 2009
TL;DR: The first large-scale and practical application of secure multiparty computation, which took place in January 2008, is reported on and the novel cryptographic protocols used are reported on.
Abstract: In this note, we report on the first large-scale and practical application of secure multiparty computation, which took place in January 2008. We also report on the novel cryptographic protocols that were used.
TL;DR: Lasing in Metal-Insulator-Metal waveguides filled with electrically pumped semiconductor cores, with core width dimensions below the diffraction limit is demonstrated, showing that losses in sub-wavelength MIM waveguide can be overcome to create small plasmon mode lasers at wavelengths near 1500 nm.
Abstract: We demonstrate lasing in Metal-Insulator-Metal (MIM) waveguides filled with electrically pumped semiconductor cores, with core width dimensions below the diffraction limit. Furthermore these waveguides propagate a transverse magnetic (TM0) or so called gap plasmon mode [1-4]. Hence we show that losses in sub-wavelength MIM waveguides can be overcome to create small plasmon mode lasers at wavelengths near 1500nm. We also give results showing room temperature lasing in MIM waveguides, with approximately 310nm wide semiconductor cores which propagate a transverse electric mode.
01 Jan 2009
TL;DR: The central challenge in post-quantum cryptography is to meet demands for cryptographic usability and flexibility without sacrificing confidence.
Abstract: Quantum computers will break today's most popular public-key cryptographic systems, including RSA, DSA, and ECDSA. This book introduces the reader to the next generation of cryptographic algorithms, the systems that resist quantum-computer attacks: in particular, post-quantum public-key encryption systems and post-quantum public-key signature systems. Leading experts have joined forces for the first time to explain the state of the art in quantum computing, hash-based cryptography, code-based cryptography, lattice-based cryptography, and multivariate cryptography. Mathematical foundations and implementation issues are included. This book is an essential resource for students and researchers who want to contribute to the field of post-quantum cryptography.
10 Jun 2009
TL;DR: This work presents a new edge bundling method that uses a self‐organizing approach to bundling in which edges are modeled as flexible springs that can attract each other, in contrast to previous methods, which require the graph to contain a hierarchy for this.
Abstract: Graphs depicted as node-link diagrams are widely used to show relationships between entities. However, nodelink diagrams comprised of a large number of nodes and edges often suffer from visual clutter. The use of edge bundling remedies this and reveals high-level edge patterns. Previous methods require the graph to contain a hierarchy for this, or they construct a control mesh to guide the edge bundling process, which often results in bundles that show considerable variation in curvature along the overall bundle direction. We present a new edge bundling method that uses a self-organizing approach to bundling in which edges are modeled as flexible springs that can attract each other. In contrast to previous methods, no hierarchy is used and no control mesh. The resulting bundled graphs show significant clutter reduction and clearly visible high-level edge patterns. Curvature variation is furthermore minimized, resulting in smooth bundles that are easy to follow. Finally, we present a rendering technique that can be used to emphasize the bundling.
TL;DR: This paper will show that using a more declarative approach can assist in a better balance between flexibility and support, by presenting the Declare framework that aims to take care of the full spectrum of flexibility while at the same time supports the user using recommendations and other process-mining-based diagnostics.
Abstract: Today’s process-aware information systems tend to either support business processes or provide flexibility. Classical workflow management systems offer good process support as long as the processes are structured and do not require much flexibility. Information systems that allow for flexibility have a tendency to lack process-related support. If systems offer guidance, then they are typically also inclined to ‘‘enforce guidelines’’ and are perceived as inflexible. Moreover, implementing flexible systems is far from trivial. This paper will show that using a more declarative approach can assist in a better balance between flexibility and support. This is demonstrated by presenting the Declare framework that aims to take care of the full spectrum of flexibility while at the same time supports the user using recommendations and other process-mining-based diagnostics.
TL;DR: In this paper, a molecular theory of the structure sensitivity of catalytic reactions based on the computed activation energies of corresponding elementary reaction steps on transition metal surfaces is proposed, which can be used to model particle-dependent reactivity changes in heterogeneous catalytic systems.
Abstract: The burgeoning field of nanoscience has stimulated an intense interest in properties that depend on particle size. For transition metal particles, one important property that depends on size is catalytic reactivity, in which bonds are broken or formed on the surface of the particles. Decreased particle size may increase, decrease, or have no effect on the reaction rates of a given catalytic system. This Account formulates a molecular theory of the structure sensitivity of catalytic reactions based on the computed activation energies of corresponding elementary reaction steps on transition metal surfaces. Recent progress in computational catalysis, surface science, and nanochemistry has significantly improved our theoretical understanding of particle-dependent reactivity changes in heterogeneous catalytic systems. Reactions that involve the cleavage or formation of molecular π-bonds, as in CO or N2, must be distinguished from reactions that involve the activation of σ-bonds, such as CH bonds in methane. Th...
TL;DR: A consistent and quantitative correlation between solar-cell performance, photophysical data and the three-dimensional morphology has been obtained for devices with different layer thicknesses that enables differentiating between generation and transport as limiting factors to performance.
Abstract: The efficiency of polymer solar cells critically depends on the intimacy of mixing of the donor and acceptor semiconductors used in these devices to create charges and on the presence of unhindered percolation pathways in the individual components to transport holes and electrons. The visualization of these bulk heterojunction morphologies in three dimensions has been challenging and has hampered progress in this area. Here, we spatially resolve the morphology of 2%-efficient hybrid solar cells consisting of poly(3-hexylthiophene) as the donor and ZnO as the acceptor in the nanometre range by electron tomography. The morphology is statistically analysed for spherical contact distance and percolation pathways. Together with solving the three-dimensional exciton-diffusion equation, a consistent and quantitative correlation between solar-cell performance, photophysical data and the three-dimensional morphology has been obtained for devices with different layer thicknesses that enables differentiating between generation and transport as limiting factors to performance.
TL;DR: In this paper, a systematic magnetic force microscope study indicates that ferromagnetism in graphite is the result of localized spins that arise at grain boundaries, which usually only occurs in materials containing elements that form covalent 3d and 4f bonds.
Abstract: Ferromagnetism usually only occurs in materials containing elements that form covalent 3d and 4f bonds. Its occurrence in pure carbon is therefore surprising, even controversial. A systematic magnetic force microscope study indicates that ferromagnetism in graphite is the result of localized spins that arise at grain boundaries.
TL;DR: After annealing treatment, genuine 3D nanoscale networks are formed with high crystalline order and favorable concentration gradients of both P3HT and PCBM through the thickness of the photoactive layer, which accounts for a considerable increase of the power conversion efficiency in corresponding solar cell devices.
Abstract: In this study, the three-dimensional (3D) nanoscale organization in the photoactive layers of poly(3-hexylthiophene) (P3HT) and a methanofullerene derivative (PCBM) is revealed by electron tomography. Morphologies suggested by previous experimental evidence were, for the first time, observed directly with a nanometer resolution and studied in detail. After annealing treatment, either at elevated temperature or during slow solvent evaporation, genuine 3D nanoscale networks are formed with high crystalline order and favorable concentration gradients of both P3HT and PCBM through the thickness of the photoactive layer. These favorable morphological changes account for a considerable increase of the power conversion efficiency in corresponding solar cell devices.
TL;DR: It is found that silver(I) complexes of polymer-functionalized N-heterocyclic carbenes, which are latent organocatalysts, catalyse a transesterification reaction when exposed to ultrasound in solution and ultrasonic activation of a ruthenium biscarbene complex with appended polymer chains results in catalysis of olefin metathesis reactions.
Abstract: Homogeneously catalysed reactions can be 'switched on' by activating latent catalysts. Usually, activation is brought about by heat or an external chemical agent. However, activation of homogeneous catalysts with a mechanical trigger has not been demonstrated. Here, we introduce a general method to activate latent catalysts by mechanically breaking bonds between a metal and one of its ligands. We have found that silver(I) complexes of polymer-functionalized N-heterocyclic carbenes, which are latent organocatalysts, catalyse a transesterification reaction when exposed to ultrasound in solution. Furthermore, ultrasonic activation of a ruthenium biscarbene complex with appended polymer chains results in catalysis of olefin metathesis reactions. In each case, the catalytic activity results from ligand dissociation, brought about by transfer of mechanical forces from the polymeric substituents to the coordination bond. Mechanochemical catalyst activation has potential applications in transduction and amplification of mechanical signals, and mechanically initiated polymerizations hold promise as a novel repair mechanism in self-healing materials.
04 Apr 2009
TL;DR: In this article, the authors present an in-depth, five-week ethnographic study that followed 6 individuals during an actual purchase of the Apple iPhone and found prolonged use to be motivated by different qualities than the ones that provided positive initial experiences.
Abstract: A recent trend in Human-Computer Interaction (HCI) research addresses human needs that go beyond the instrumental, resulting in an increasing body of knowledge about how users form overall evaluative judgments on the quality of interactive products. An aspect largely neglected so far is that of temporality, i.e. how the quality of users' experience develops over time. This paper presents an in-depth, five-week ethnographic study that followed 6 individuals during an actual purchase of the Apple iPhone". We found prolonged use to be motivated by different qualities than the ones that provided positive initial experiences. Overall, while early experiences seemed to relate mostly to hedonic aspects of product use, prolonged experiences became increasingly more tied to aspects reflecting how the product becomes meaningful in one's life. Based on the findings, we promote three directions for CHI practice: designing for meaningful mediation, designing for daily rituals, and designing for the self.
TL;DR: In this paper, a detailed reaction mechanism for small hydrocarbons combustion with possibly full implementation of available kinetic data related to the prompt NO route via NCN was presented, which can accurately predict the NO formation in lean and rich flames of methane, ethylene, ethane and propane.
06 Dec 2009
TL;DR: This paper studies the classification with independency constraints problem: find an accurate model for which the predictions are independent from a given binary attribute and proposes two solutions and presents an empirical validation.
Abstract: In this paper we study the problem of classifier learning where the input data contains unjustified dependencies between some data attributes and the class label. Such cases arise for example when the training data is collected from different sources with different labeling criteria or when the data is generated by a biased decision process. When a classifier is trained directly on such data, these undesirable dependencies will carry over to the classifier’s predictions. In order to tackle this problem, we study the classification with independency constraints problem: find an accurate model for which the predictions are independent from a given binary attribute. We propose two solutions for this problem and present an empirical validation.
TL;DR: In this article, a wide range of potentially suitable solvents for the dissolution and homogeneous processing of cellulose was screened and some remarkable results were obtained, for example, an odd-even effect was found for different alkyl side-chain lengths of the imidazolium chlorides which could not be observed for the bromides.
TL;DR: Genetically encoded fluorescence resonance energy transfer (FRET)-based sensors that display a large ratiometric change upon Zn2+ binding, have affinities that span the pico- to nanomolar range and can readily be targeted to subcellular organelles are developed.
Abstract: We developed genetically encoded fluorescence resonance energy transfer (FRET)-based sensors that display a large ratiometric change upon Zn(2+) binding, have affinities that span the pico- to nanomolar range and can readily be targeted to subcellular organelles. Using this sensor toolbox we found that cytosolic Zn(2+) was buffered at 0.4 nM in pancreatic beta cells, and we found substantially higher Zn(2+) concentrations in insulin-containing secretory vesicles.
27 Aug 2009
TL;DR: In this paper, the problem of ranking all process models in a repository according to their similarity with respect to a given process model is investigated, and four graph matching algorithms, ranging from a greedy one to a relatively exhaustive one, are evaluated.
Abstract: We investigate the problem of ranking all process models in a repository according to their similarity with respect to a given process model. We focus specifically on the application of graph matching algorithms to this similarity search problem. Since the corresponding graph matching problem is NP-complete, we seek to find a compromise between computational complexity and quality of the computed ranking. Using a repository of 100 process models, we evaluate four graph matching algorithms, ranging from a greedy one to a relatively exhaustive one. The results show that the mean average precision obtained by a fast greedy algorithm is close to that obtained with the most exhaustive algorithm.
05 May 2009
TL;DR: This paper proposes a new classification scheme for learning unbiased models on biased training data based on massaging the dataset by making the least intrusive modifications which lead to an unbiased dataset and learns a non-discriminating classifier.
Abstract: Classification models usually make predictions on the basis of training data. If the training data is biased towards certain groups or classes of objects, e.g., there is racial discrimination towards black people, the learned model will also show discriminatory behavior towards that particular community. This partial attitude of the learned model may lead to biased outcomes when labeling future unlabeled data objects. Often, however, impartial classification results are desired or even required by law for future data objects in spite of having biased training data. In this paper, we tackle this problem by introducing a new classification scheme for learning unbiased models on biased training data. Our method is based on massaging the dataset by making the least intrusive modifications which lead to an unbiased dataset. On this modified dataset we then learn a non-discriminating classifier. The proposed method has been implemented and experimental results on a credit approval dataset show promising results: in all experiments our method is able to reduce the prejudicial behavior for future classification significantly without loosing too much predictive accuracy.
TL;DR: A new approach for the stability analysis and controller synthesis of networked control systems (NCSs) with uncertain, time-varying, network delays is presented, based on the Jordan form of the continuous-time plant.
Abstract: In this technical note, a new approach for the stability analysis and controller synthesis of networked control systems (NCSs) with uncertain, time-varying, network delays is presented. Based on the Jordan form of the continuous-time plant, a discrete-time representation of the NCS is derived. Using this model for delays that can be both smaller and larger than the sampling interval, sufficient LMI conditions for stability and feedback stabilization are proposed. The results are illustrated by a typical motion control example.
01 Aug 2009
TL;DR: In this paper, the authors present a process discovery algorithm using concepts taken from the language-based theory of regions, a well-known Petri net research area and identify a number of shortcomings of this theory from the process discovery perspective, and provide solutions based on integer linear programming.
Abstract: The research domain of process discovery aims at constructing a process model (e.g. a Petri net) which is an abstract representation of an execution log. Such a model should (1) be able to reproduce the log under consideration and (2) be independent of the number of cases in the log. In this paper, we present a process discovery algorithm where we use concepts taken from the language-based theory of regions, a well-known Petri net research area. We identify a number of shortcomings of this theory from the process discovery perspective, and we provide solutions based on integer linear programming.
TL;DR: In this paper, the authors present a thermal comfort analysis for residential buildings based on thermal comfort models and thermal comfort scales, which are defined in an algorithm, easily implementable in any BES code.