Showing papers by "Helsinki University of Technology published in 2005"
TL;DR: The authors used an augmented Cobb-Douglas production to explore firm formation and technological innovation as separate determinants of growth, finding that only high growth potential entrepreneurship has a significant impact on economic growth.
Abstract: Studies on the impact of technological innovation on growth have been largely mute on the role of␣new firm formation. Using cross-sectional data on the 37 countries participating in GEM 2002, this paper uses an augmented Cobb–Douglas production to explore firm formation and technological innovation as separate determinants of growth. One area of interest is the contrast between different types of entrepreneurial activities as measured using GEM Total Entrepreneurial Activity (TEA) rates – high growth potential TEA, necessity TEA, opportunity TEA and overall TEA. Of the four types of entrepreneurship, only high growth potential entrepreneurship is found to have a significant impact on economic growth. This finding is consistent with extant findings in the literature that it is fast growing new firms, not new firms in general, that accounted for most of the new job creation by small and medium enterprises in advanced countries.
1,395 citations
TL;DR: In this article, a review of the literature on interfacial reactions between pure Sn or Sn-rich solders and common base metals used in Pb-free electronics production is presented.
Abstract: The objective of this review is to study interfacial reactions between pure Sn or Sn-rich solders, and common base metals used in Pb-free electronics production. In particular, the reasons leading to the observed interfacial reactions products and their metallurgical evolution have been analyzed. Results presented in the literature have been critically evaluated with the help of combined thermodynamic–kinetic approach based on the concept of local equilibrium and microstructural knowledge. The following conclusions have been reached: Firstly, the formations of intermetallic compounds in solid/liquid reaction couples are primarily controlled by the dissolution processes of base metals. Other factors that need be considered are the thermodynamic driving force for the formation of intermetallic compounds, their structures and concentration profiles in liquid. Secondly, annealing of solder interconnections in solid state can drastically change the microstructures formed in the solid/liquid reactions, especially if only one of the components in the solder takes part in the interfacial reactions. Thirdly, additional elements can have three major effects on the binary reactions between a base metal and Sn: (i) they can increase or decrease the reaction/growth rates, (ii) the additives can change the physical properties of the phases formed, and (iii) they can form additional reaction products or displace the binary equilibrium phases by forming new reaction products. Finally, if the local stable or metastable equilibrium is established at the interface, stability information together with kinetic considerations can provide a feasible approach to analyze interfacial reactions, which can have significant impact on the reliability of soldered electronics assemblies.
1,024 citations
TL;DR: This paper applies motif scores and clustering coefficient to financial and metabolic networks and finds that inclusion of weights may considerably modify the conclusions obtained from the study of unweighted characteristics.
Abstract: The local structure of unweighted networks can be characterized by the number of times a subgraph appears in the network. The clustering coefficient, reflecting the local configuration of triangles, can be seen as a special case of this approach. In this paper we generalize this method for weighted networks. We introduce subgraph ``intensity'' as the geometric mean of its link weights and ``coherence'' as the ratio of the geometric to the corresponding arithmetic mean. Using these measures, motif scores and clustering coefficient can be generalized to weighted networks. To demonstrate these concepts, we apply them to financial and metabolic networks and find that inclusion of weights may considerably modify the conclusions obtained from the study of unweighted characteristics.
957 citations
TL;DR: In this paper, the authors classify collaboration initiatives using a conceptual water-tank analogy, and discuss their dynamic behavior and key characteristics, concluding that the effectiveness of supply chain collaboration relies upon two factors: the level to which it integrates internal and external operations, and the efforts are aligned to the supply chain settings in terms of the geographical dispersion, the demand pattern, and product characteristics.
747 citations
TL;DR: In this paper, a cognitive approach was proposed to probe entrepreneurs' motivations to internationalize and capture their mental models, highlighting the benefits to be gained from and the challenges associated with using a Cognitive approach to international entrepreneurship research.
564 citations
TL;DR: In this paper, the authors provide a perspective on the nature of service infusion in manufacturing companies based on a case analysis in the context of a maintenance management solution for industrial production equipment.
Abstract: Purpose – To provide a perspective on the nature of service infusion in manufacturing companies based on a case analysis in the context of a maintenance management solution for industrial production equipment.Design/methodology/approach – The paper first discusses how manufacturers becoming service providers is treated in the literature. Next, a qualitative single‐case study is reported, in which a troublesome business concept was surveyed through 35 thematic focus group interviews. The analysis revealed a set of challenges that were compared to arrive at a conclusion, the paradox.Findings – The findings suggest that many challenges stemmed from the manufacturing‐oriented way of doing business. This further indicates that the common implicit view, that manufacturers can shift to service provision steadily, by adding service offerings to their total offering one by one, may actually be hazardous.Research limitations/implications – The limitations are based on the methodology. First, the case study focuses ...
559 citations
02 Apr 2005
TL;DR: In this article, the Re-source Competition Framework (RCF) was used to predict the performance of Web search tasks on mobile phones while moving through nine varied but typical urban situations.
Abstract: When on the move, cognitive resources are reserved partly for passively monitoring and reacting to contexts and events, and partly for actively constructing them. The Re-source Competition Framework (RCF), building on the Multiple Resources Theory, explains how psychosocial tasks typical of mobile situations compete for cognitive resources and then suggests that this leads to the depletion of resources for task interaction and eventually results in the breakdown of fluent interaction. RCF predictions were tested in a semi-naturalistic field study measuring attention during the performance of assigned Web search tasks on mobile phone while moving through nine varied but typical urban situations. Notably, we discovered up to eight-fold differentials between micro-level measurements of atten-tional resource fragmentation, for example from spans of over 16 seconds in a laboratory condition dropping to bursts of just a few seconds in difficult mobile situations. By cali-brating perceptual sampling, reducing resources from tasks of secondary importance, and resisting the impulse to switch tasks before finalization, participants compensated for the resource depletion. The findings are compared to previous studies in office contexts. The work is valuable in many areas of HCI dealing with mobility.
541 citations
TL;DR: In this paper, the effect of strain rate on strain-induced γ → α-martensite transformation and mechanical behavior of austenitic stainless steel grades EN 1.4318 (AISI 301LN) and EN1.4301 (A ISI 304) was studied at strain rates ranging between 3×10−4 and 200 s−1.
Abstract: The effect of strain rate on strain-induced γ → α′-martensite transformation and mechanical behavior of austenitic stainless steel grades EN 1.4318 (AISI 301LN) and EN 1.4301 (AISI 304) was studied at strain rates ranging between 3×10−4 and 200 s−1. The most important effect of the strain rate was found to be the adiabatic heating that suppresses the strain-induced γ → α′ transformation. A correlation between the work-hardening rate and the rate of γ → α′ transformation was found. Therefore, the changes in the extent of the α′-martensite formation strongly affected the work-hardening rate and the ultimate tensile strength of the materials. Changes in the martensite formation and work-hardening rate affected also the ductility of the studied steels. Furthermore, it was shown that the square root of the α′-martensite fraction is a linear function of flow stress. This indicates that the formation of α′-martensite affects the stress by influencing the dislocation density of the austenite phase. Olson-Cohen analysis of the martensite measurement results did not indicate any effect of strain rate on shear band formation, which was contrary to the transmission electron microscopy (TEM) examinations. The β parameter decreased with increasing strain rate, which indicates a decrease in the chemical driving force of the α → α′ transformation.
387 citations
University of Oxford1, University of Edinburgh2, Microsoft3, Max Planck Society4, French Institute for Research in Computer Science and Automation5, RWTH Aachen University6, Orange S.A.7, University of Southampton8, Technische Universität Darmstadt9, Helsinki University of Technology10, Middle East Technical University11
TL;DR: The PASCAL Visual Object Classes Challenge (PASCALVOC) as mentioned in this paper was held from February to March 2005 to recognize objects from a number of visual object classes in realistic scenes (i.e. not pre-segmented objects).
Abstract: The PASCAL Visual Object Classes Challenge ran from February to March 2005. The goal of the challenge was to recognize objects from a number of visual object classes in realistic scenes (i.e. not pre-segmented objects). Four object classes were selected: motorbikes, bicycles, cars and people. Twelve teams entered the challenge. In this chapter we provide details of the datasets, algorithms used by the teams, evaluation criteria, and results achieved.
381 citations
TL;DR: The results suggest that these same motor-cortex beta sources are modulated by benzodiazepine, and it is found that an increase in IPSCs onto inhibitory neurons was more important for generating neuronal synchronization in the beta band than an increased inIPSCs onto excitatory pyramidal cells.
377 citations
TL;DR: This work exploits the application of similarity measures and a related visual tool to study the natural self-organizing clustering of many independent components from multiple individual data sets in the subject space and exploits commonalities across multiple subject-specific patterns for blind group and subgroup pattern extraction and selection.
TL;DR: In this article, the microencapsulation of d-limonene by spray drying was investigated with respect to the effects of emulsion droplet size, powder particle size, as well as to the effect of various kinds of matrices (gum arabic, maltodextrin, and modified starch) on its stability.
Abstract: The microencapsulation of d -limonene by spray drying was investigated with respect to the effects of emulsion droplet size, powder particle size, as well as to the effects of various kinds of matrices (gum arabic, maltodextrin, and modified starch) on its stability. It was realized by studying release characteristics and oxidative stability during storage. The release and the oxidation decreased deeply with an increase in powder and emulsion particle size for gum arabic and maltodextrin materials. Further, the distributions of emulsion size in the powder showed an increase in the fraction of large emulsion droplets and changed to a bimodal distribution. However, the modified starch HI-CAP 100 showed a higher stability of encapsulated d -limonene than the others. The influence of powder and emulsion size on its encapsulated flavor as well as the change in the emulsion size during storage could not be observed. Industrial Relevance Spray drying is a common and useful unit operation for microencapsulation of food ingredients. Data on emulsion droplet size and on powder size on product stability provide conflicting results which makes a systematic study regarding these factors highly relevant. The data suggest that an optimal size of flavour powder should be selected for high retention during spray drying, stability during storage and for the ability to control release of flavour.
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TL;DR: In this article, the authors analyze the evolution of the concept of Integrated Water Resources Management (IWRM) at international conferences over the past three decades and address the prospects of IWRM in resolving the current water crisis.
Abstract: This paper analyzes the evolution of the concept of Integrated Water Resources Management (IWRM) at international conferences over the past three decades and addresses the prospects of IWRM in resolving the current water crisis. It also identifies seven crucial challenges to implementing IWRM. Our rivers and aquifers are the life-blood of the planet. To achieve sustainable development, we must manage our most vital natural resource, water, in an integrated manner, or precisely through Integrated Water Resources Management. Since water is fundamental to many aspects of life, and to the surrounding natural environment, there is a need not only to review IWRM’s evolution in the last three decades, but also to identify future challenges to its implementation.
TL;DR: In this paper, an original regime of operation for flat superlenses formed by electromagnetic crystals is proposed, which does not involve negative refraction and amplification of evanescent waves in contrast to the perfect lenses formed by left-handed media.
Abstract: An original regime of operation for flat superlenses formed by electromagnetic crystals is proposed. This regime does not involve negative refraction and amplification of evanescent waves in contrast to the perfect lenses formed by left-handed media. The sub-wavelength spatial spectrum of a source is canalized by the eigenmodes of the crystal having the same longitudinal components of wave vector and group velocities directed across the slab. The regime is implemented at low frequencies with respect to the crystal period by using capacitively loaded wire media. The resolution of λ/6 is demonstrated. The thickness of the lens is not related with the distance to the source and the lens can be made thick enough.
TL;DR: In this article, the authors used positron annihilation spectroscopy to study the introduction and recovery of point defects in electron-irradiated $n$-type ZnO.
Abstract: We have used positron annihilation spectroscopy to study the introduction and recovery of point defects in electron-irradiated $n$-type ZnO. The irradiation (${E}_{\mathrm{el}}=2\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}$, fluence $6\ifmmode\times\else\texttimes\fi{}{10}^{17}{\mathrm{cm}}^{\ensuremath{-}2}$) was performed at room temperature, and isochronal annealings were performed from 300 to 600 K. In addition, monochromatic illumination of the samples during low-temperature positron measurements was used in identification of the defects. We distinguish two kinds of vacancy defects: the Zn and O vacancies, which are either isolated or belong to defect complexes. In addition, we observe negative-ion-type defects, which are attributed to O interstitials or O antisites. The Zn vacancies and negative ions act as compensating centers and are introduced at a concentration $[{V}_{\mathrm{Zn}}]\ensuremath{\simeq}{c}_{\mathrm{ion}}\ensuremath{\simeq}2\ifmmode\times\else\texttimes\fi{}{10}^{16}{\mathrm{cm}}^{\ensuremath{-}3}$. The O vacancies are introduced at a 10-times-larger concentration $[{V}_{\mathrm{O}}]\ensuremath{\simeq}3\ifmmode\times\else\texttimes\fi{}{10}^{17}{\mathrm{cm}}^{\ensuremath{-}3}$ and are suggested to be isolated. The O vacancies are observed as neutral at low temperatures, and an ionization energy of 100 meV could be fitted with the help of temperature-dependent Hall data, thus indicating their deep donor character. The irradiation-induced defects fully recover after the annealing at 600 K, in good agreement with electrical measurements. The Zn vacancies recover in two separate stages, indicating that the Zn vacancies are parts of two different defect complexes. The O vacancies anneal simultaneously with the Zn vacancies at the later stage, with an activation energy of ${E}_{V,\mathrm{O}}^{m}=1.8\ifmmode\pm\else\textpm\fi{}0.1\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$. The negative ions anneal out between the two annealing stages of the vacancies.
TL;DR: Overall, the results indicate that ClO2 will only be effective to oxidize certain compound classes such as the investigated classes of sulfonamide and macrolide antibiotics, and estrogens.
TL;DR: The results propose that the functioning of certain classes of membrane proteins is regulated by changes in the lateral pressure profile, which can be altered by a change in lipid content.
Abstract: The paradigm of biological membranes has recently gone through a major update. Instead of being fluid and homogeneous, recent studies suggest that membranes are characterized by transient domains with varying fluidity. In particular, a number of experimental studies have revealed the existence of highly ordered lateral domains rich in sphingomyelin and cholesterol (CHOL). These domains, called functional lipid rafts, have been suggested to take part in a variety of dynamic cellular processes such as membrane trafficking, signal transduction, and regulation of the activity of membrane proteins. However, despite the proposed importance of these domains, their properties, and even the precise nature of the lipid phases, have remained open issues mainly because the associated short time and length scales have posed a major challenge to experiments. In this work, we employ extensive atom-scale simulations to elucidate the properties of ternary raft mixtures with CHOL, palmitoylsphingomyelin (PSM), and palmitoyloleoylphosphatidylcholine. We simulate two bilayers of 1,024 lipids for 100 ns in the liquid-ordered phase and one system of the same size in the liquid-disordered phase. The studies provide evidence that the presence of PSM and CHOL in raft-like membranes leads to strongly packed and rigid bilayers. We also find that the simulated raft bilayers are characterized by nanoscale lateral heterogeneity, though the slow lateral diffusion renders the interpretation of the observed lateral heterogeneity more difficult. The findings reveal aspects of the role of favored (specific) lipid–lipid interactions within rafts and clarify the prominent role of CHOL in altering the properties of the membrane locally in its neighborhood. Also, we show that the presence of PSM and CHOL in rafts leads to intriguing lateral pressure profiles that are distinctly different from corresponding profiles in nonraft-like membranes. The results propose that the functioning of certain classes of membrane proteins is regulated by changes in the lateral pressure profile, which can be altered by a change in lipid content.
TL;DR: In this article, the authors introduce hot-spot and top-oil temperature thermal models for more accurate temperature calculations during transient states based on data received in a normal heat run test (i.e., the top oil in the tank of the transformer and the average winding-to-average oil gradient).
Abstract: The aim of this paper is to introduce hot-spot and top-oil temperature thermal models for more accurate temperature calculations during transient states based on data received in a normal heat run test (i.e., the top oil in the tank of the transformer and the average winding-to-average oil gradient). Oil viscosity changes and loss variation with temperature are taken into account. The new thermal models will be validated using experimental (fiber-optic test) results obtained at varying load current on a 250-MVA-ONAF-cooled unit, a 400-MVA-ONAF-cooled unit and a 605-MVA-OFAF-cooled unit. The results are also compared with the IEEE-Loading guide (1995) Annex G method.
TL;DR: In this article, a survey of 48 progressive companies was conducted to identify what IT solutions they have implemented in supply chain management, followed by 18 in-depth case studies to identify the mechanisms for achieving benefits of IT in SCM.
Abstract: Purpose – To provide empirical evidence of benefits from IT in supply chain management.Design/methodology/approach – Data in this qualitative study were collected through multiple enquiries. SCM consultant interviews gave an understanding of the current state of practice. A survey of 48 progressive companies was conducted to identify what IT solutions they have implemented in SCM. This was followed by 18 in‐depth case studies to identify the mechanisms for achieving benefits of IT in SCM.Findings – Based on the empirical studies five propositions are presented on the use and benefits of IT. First, successful companies have developed focused e‐business solutions for improving customer service elements that are most important in their business. Second, improved efficiency allows company personnel to focus more on critical business activities. Third, the use of e‐business solutions improves information quality. Fourth, e‐business solutions support planning collaboration and improved agility of the supply net...
TL;DR: Broca's region, classically considered a motor speech-production area, is involved in action understanding and imitation and it also seems to help in sequencing of actions.
Abstract: Broca’s region, classically considered a motor speech-production area, is involved in action understanding and imitation. It also seems to help in sequencing of actions. Broca’s region might have evolved for interindividual communication, both by gestures and speech.
TL;DR: In this article, the authors studied the effect of removing oxygen from carboxylic groups from wood-derived bio-oil with model compounds, methyl heptanoate and methyl hexanoate, on sulphided NiMo/γ-Al2O3 and CoMo/αγ-α 2O3 catalysts in a flow reactor.
TL;DR: In this paper, the effect of background subtraction on the analysis results of X-ray photoelectron spectroscopy (XPS) was studied for the case of two chemical states in both samples.
TL;DR: In this article, auditory event-related potentials (ERP) were studied in 15 children with autism and their controls, and their responses were recorded for pitch, duration, and vowel changes in speech stimuli, and for corresponding changes in the non-speech counterparts of the stimuli, while the children watched silent videos and ignored the stimuli.
TL;DR: In this article, the UVRR and FT-IR spectra of acetone extracts showed that lignin became partly acetone soluble after a heat treatment of 180°C or greater.
Abstract: Scots pine planks were heat‐treated under steam in a temperature range of 100–240°C at every 20°C. Changes in chemical structure of the wood samples were examined with UV resonance Raman (UVRR) and Fourier transform infrared (FT‐IR) spectroscopies. Prior to the FT‐IR and UVRR analysis, the heartwood part of wood samples were ground and extracted with acetone. Both the extracts and the extracted samples were analyzed. In addition, Klason lignin contents of the samples were determined. The FT‐IR and UVRR spectroscopy were powerful techniques to monitor chemical changes in the heat‐treated wood samples. Results confirmed most of what determined previously by other research groups using different techniques. The UVRR and FT‐IR spectra of acetone extracts showed that lignin became partly acetone soluble after a heat treatment of 180°C or greater. Increased levels of free phenolic hydroxyl groups were detected in lignin, probably due to cleavages of β‐O‐aryl ether interunit linkages. The amount of extr...
TL;DR: In this article, single-walled carbon nanotubes (CNTs) were synthesized at different conditions by a novel aerosol method based on the introduction of pre-formed iron catalyst particles into conditions leading to CNT formation.
TL;DR: The authors analyzes the evolution of the concept of Integrated Water Resources Management (IWRM) at international conferences over the past three decades and addresses the prospects of IWRM in the future.
Abstract: This paper analyzes the evolution of the concept of Integrated Water Resources Management (IWRM) at international conferences over the past three decades and addresses the prospects of IWRM in reso...
TL;DR: In this paper, a tension is discovered between recursive practices contributing to ontological security, achieved through pre dictability, and adaptive practices, achieving individual ownership of strategy, achieved by personal interpretation.
Abstract: Research into the practice of organizational strategy is centered on the work of individual strategists. Strategic champions, individuals going beyond their operative responsibilities in strategic issues, are key stakeholders in research into strategy-as-practice. In this article, interview accounts of 158 champions from 12 organizations are analyzed for how strate gic practices enable and disable strategic champions in their work. A tension is discovered between recursive practices contributing to ontological security, achieved through pre dictability, and adaptive practices contributing to individual ownership of strategy, achieved through personal interpretation.
TL;DR: Combined field integral equation (CFIE) is applied for computing electromagnetic scattering by arbitrarily shaped three dimensional dielectric and composite objects in this paper, where the authors present a CFIE formulation which can be used in the analysis of piecewise dielectrics and composite metallic objects with junctions, and properly choosing the coupling coefficients of the equations the conditioning of the discretized matrix equation can be essentially improved and rapidly converging iterative solutions can be obtained even without preconditioning.
Abstract: Combined field integral equation (CFIE) is applied for computing electromagnetic scattering by arbitrarily shaped three dimensional dielectric and composite objects. The objectives of this paper are as follows. First, to present a CFIE formulation which can be used in the analysis of piecewise dielectric and composite metallic and dielectric objects with junctions. Second, to show that properly choosing the coupling coefficients of the equations the conditioning of the discretized matrix equation can be essentially improved and rapidly converging iterative solutions can be obtained even without preconditioning.
TL;DR: A regularized Gauss-Newton method for solving the inverse problem of parameter reconstruction from boundary data in frequency-domain diffuse optical tomography by means of an iterative Krylov method, which accesses the Hessian only in the form of matrix-vector products.
Abstract: We present a regularized Gauss-Newton method for solving the inverse problem of parameter reconstruction from boundary data in frequency-domain diffuse optical tomography. To avoid the explicit formation and inversion of the Hessian which is often prohibitively expensive in terms of memory resources and runtime for large-scale problems, we propose to solve the normal equation at each Newton step by means of an iterative Krylov method, which accesses the Hessian only in the form of matrix-vector products. This allows us to represent the Hessian implicitly by the Jacobian and regularization term. Further we introduce transformation strategies for data and parameter space to improve the reconstruction performance. We present simultaneous reconstructions of absorption and scattering distributions using this method for a simulated test case and experimental phantom data.