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  • 1. Acs, Zoltan
    et al.
    Braunerhjelm, Pontus
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS. KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Economics.
    The Entrepreneruship-Philanthropy Nexus: Implication for internationalization2005Report (Other academic)
    Abstract [en]

    This paper examines how Sweden and the United States have been impacted by philanthropicactivities, commercialization of university-based knowledge and internationalentrepreneurship. The analysis comprises a detailed case study of Swedish and U.S.universities, as well as a statistical analysis of the impact of philanthropy on economicgrowth. The results show that the United States has prompted a university system based oncompetition and variety, with an emphasis on philanthropy, promoting knowledge creation.International entrepreneurship has been an important mechanism by which this knowledge isglobalized leading to increased economic growth. Conversely, Swedish universities werecharacterized by less commercialized R&D and weak links to the commercial sector, rootedtraditionally in dependence on tax-financed and homogenous university structure. TheSwedish model has begun to change with important implications for development in smallerdomestic markets. The analysis has important implications for knowledge creation as asource of economic growth through international entrepreneurship taking advantage ofglobalization, especially for smaller countries.

  • 2.
    Adane, Tigist Fetene
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology. KTH.
    Bianchi, Maria Floriana
    KTH, School of Industrial Engineering and Management (ITM).
    Archenti, Andreas
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology. KTH, School of Industrial Engineering and Management (ITM), Centres, Design and Management of Manufacturing Systems, DMMS.
    Nicolescu, Mihai
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Performance evaluation of machining strategy for engine-block manufacturing2015In: Performance evaluation of machining strategy for engine-block manufacturing, ISSN 1895-7595, Vol. 15, no 4, p. 81-102Article in journal (Refereed)
    Abstract [en]

    This paper will introduce a novel methodology for the performance evaluation of machining strategies of engine block manufacturing. The manufacturing of engine components is vital to the automotive and vehicle manufacturing industries. Machining is critical processes in the production of these parts. To survive and excel in the competitive manufacturing environment, companies need to improve as well as update their machining processes and evaluate the performance of their machining lines. Moreover, the lines and processes have to be robust in handling different sources of variation over time that include such examples as demand fluctuations, work-piece materials or even any changes in design specifications. A system dynamics modelling and simulation approach has been deployed to develop a methodology that captures how machining system parameters from the machining process are interacted with each other, how these connections drive performance and how new targets affect process and machine tool parameters through time. The developed model could provide an insight of how to select the crucial machining system parameters and to identify the effect of those parameters on the output of the system. In response to such an analysis, this paper provides (offers) a framework to examine machining strategies and has presented model that is useful as a decision support system for the evaluation and selection of machining strategies. Here a system dynamics methodology for modelling is applied to the milling operation and the model is based on an actual case study from the engine-block manufacturing industry.

  • 3.
    Aghaali, Habib
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Internal Combustion Engines. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Ångström, Hans-Erik
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Internal Combustion Engines. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    A review of turbocompounding as a waste heat recovery system for internal combustion engines2015In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 49, p. 813-824Article in journal (Refereed)
    Abstract [en]

    Internal combustion engines waste a large amount of fuel energy through their exhausts. Various technologies have been developed for waste heat recovery such as turbocompounds, Rankine bottoming cycles, and thermoelectric generators that reduce fuel consumption and CO2 emissions. Turbocompounding is still not widely applied to vehicular use despite the improved fuel economy, lower cost, volume, and complexity higher exhaust gas recirculation driving capability and improved transient response. This paper comprehensively reviews the latest developments and research on turbocompounding to discover important variables and provide insights into the implementation of a high-efficiency turbocompound engine. Attention should be paid to the optimization of turbocompound engines and their configurations because the major drawback of this technology is additional exhaust back-pressure, which leads to higher pumping loss in the engines. Applying different technologies and concepts on turbocompound engines makes the exhaust energy recovery more efficient and provides more freedom in the design and optimization of the engines. Turbine efficiency plays an important role in the recovery of the wasted heat so turbine design is a crucial issue in turbocompounding. In addition, variability in geometry and rotational speed of power turbines allows for more efficient turbocompound engines in different operating conditions. The conclusion drawn from this review is that turbocompounding is a promising technology for reducing fuel consumption in the coming decades in both light- and heavy-duty engines.

  • 4.
    Aghaali, Habib
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Internal Combustion Engines. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Ångström, Hans-Erik
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Internal Combustion Engines. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    The Exhaust Energy Utilization of a Turbocompound Engine Combined with Divided Exhaust Period2014Conference paper (Refereed)
    Abstract [en]

    To decrease the influence of the increased exhaust pressure of a turbocompound engine, a new architecture is developed by combining the turbocompound engine with divided exhaust period (DEP). The aim of this study is to utilize the earlier stage (blowdown) of the exhaust stroke in the turbine(s) and let the later stage (scavenging) of the exhaust stroke bypass the turbine(s). To decouple the blowdown phase from the scavenging phase, the exhaust flow is divided between two different exhaust manifolds with different valve timing. A variable valve train system is assumed to enable optimization at different load points. The fuel-saving potential of this architecture have been theoretically investigated by examining different parameters such as turbine flow capacity, blowdown valve timing and scavenging valve timing. Many combinations of these parameters are considered in the optimization of the engine for different engine loads and speeds.

    This architecture produces less negative pumping work for the same engine load point due to lower exhaust back pressure; however, the exhaust mass flow into the turbine(s) is decreased. Therefore, there is a compromise between the turbine energy recovery and the pumping work. According to this study, this combination shows fuel-saving potential in low engine speeds and limitations at high engine speeds. This is mainly due to the choked flow in the exhaust valves because this approach is using only one of the two exhaust valves at a time. To reveal the full potential of this approach, increasing the effective flow area of the valves should be studied.

  • 5.
    Aghaali, Habib
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Internal Combustion Engines. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Ångström, Hans-Erik
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Internal Combustion Engines. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Serrano, Jose R
    Universitat Politècnica de València.
    Evaluation of different heat transfer conditions on an automotive turbocharger2014In: International Journal of Engine Research, ISSN 1468-0874, E-ISSN 2041-3149, Vol. 16, no 2, p. 137-151Article in journal (Refereed)
    Abstract [en]

    This paper presents a combination of theoretical and experimental investigations for determining the main heat fluxes within a turbocharger. These investigations consider several engine speeds and loads as well as different methods of conduction, convection, and radiation heat transfer on the turbocharger. A one-dimensional heat transfer model of the turbocharger has been developed in combination with simulation of a turbocharged engine that includes the heat transfer of the turbocharger. Both the heat transfer model and the simulation were validated against experimental measurements. Various methods were compared for calculating heat transfer from the external surfaces of the turbocharger, and one new method was suggested.

    The effects of different heat transfer conditions were studied on the heat fluxes of the turbocharger using experimental techniques. The different heat transfer conditions on the turbocharger created dissimilar temperature gradients across the turbocharger. The results show that changing the convection heat transfer condition around the turbocharger affects the heat fluxes more noticeably than changing the radiation and conduction heat transfer conditions. Moreover, the internal heat transfers from the turbine to the bearing housing and from the bearing housing to the compressor are significant, but there is an order of magnitude difference between these heat transfer rates.

  • 6.
    Alenius, Emma
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Flow acoustics. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Sound Generating Flow Structures in a Thick Orifice Plate Jet2014In: Progress in Turbulence V: Proceedings of the iTi Conference in Turbulence 2012, Cham, Switzerland: Springer, 2014, p. 201-204Conference paper (Refereed)
    Abstract [en]

    The aim of thiswork is to study sound generating flowstructures in a thickcircular orifice plate jet, placed in a circular duct. Large eddy simulations (LES)are performed for two jet Mach numbers, 0.4 and 0.9. Characteristic frequenciesin the flow, and their corresponding flow structures, are identified with dynamicmode decomposition (DMD). The results show that a tonal noise is generated atfrequencies where the jet displays strong ring vortices, in the plane wave range.The main sound generating mechanisms seems to be a fluctuating mass flow at theorifice opening and a fluctuating surface force at the plate sides, caused by the ringvortices. The frequencies are believed to be chosen, and strengthened, by a feedbackmechanism between the orifice in- and outlet.

  • 7.
    Alenius, Emma
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Flow acoustics. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Åbom, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Flow acoustics. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Fuchs, Laszlo
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Large eddy simulations of acoustic-flow interaction at an orifice plate2015In: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 345, p. 162-177Article in journal (Refereed)
    Abstract [en]

    The scattering of plane waves by an orifice plate with a strong bias flow, placed in a circular or square duct, is studied through large eddy simulations and dynamic mode decomposition. The acoustic-flow interaction is illustrated, showing that incoming sound waves at a Strouhal number of 0.43 trigger a strong axisymmetric flow structure in the orifice in the square duct, and interact with a self-sustained axisymmetric oscillation in the circular duct orifice. These structures then generate a strong sound, increasing the acoustic energy at the frequency of the incoming wave. The structure triggered in the square duct is weaker than that present in the circular duct, but stronger than structures triggered by waves at other frequencies. Comparing the scattering matrix with measurements, there is a good agreement. However, the results are found to be sensitive to the inflow, where the self-sustained oscillation in the circular duct simulation is an artefact of an axisymmetric, undisturbed inflow. This illustrates a problem with using an undisturbed inflow for studying vortex-sound effects, and can be of interest when considering musical instruments, where the aim is to get maximum amplification of specific tones. Further, it illustrates that at the frequency where an amplification of acoustic energy is found for the orifice plate, the flow has a natural instability, which is suppressed by non-axisymmetry and incoming disturbances.

  • 8.
    Alenius, Emma
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Flow acoustics. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Åbom, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Flow acoustics.
    Fuchs, Laszlo
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    LES of Acoustic-Flow Interaction at an Orifice Plate2012In: 18th AIAA/CEAS Aeroacoustics Conference (33rd AIAA Aeroacoustics Conference), 2012Conference paper (Other academic)
    Abstract [en]

    The scattering of plane waves by a thick orifice plate, placed in a circular or square duct with flow, is studied through Large Eddy Simulation. The scattering matrix is computed and compared to measurements, showing reasonably good agreement except around one frequency ($St \approx 0.4$). Here a stronger amplification of acoustic energy is observed in the circular duct simulations than in the measurements and the square duct simulations. In order to improve the understanding of the interaction between an incoming wave, the flow, and the plate, a few frequencies are studied in more detail. A Dynamic Mode Decomposition is performed to identify flow structures at significant frequencies. This shows that the amplification of acoustic energy occurs at the frequency where the jet in the circular duct has an axisymmetric instability. Furthermore, the incoming wave slightly amplifies this instability, and suppresses background flow fluctuations.

  • 9.
    Alenius, Emma
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Flow acoustics. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Åbom, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Flow acoustics. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Fuchs, Laszlo
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Scattering of Plane Waves by a Constriction2011In: Proceedings of ASME Turbo Expo 2011, Vol 7, Parts A-C, American Society Of Mechanical Engineers , 2011, p. 1043-1052Conference paper (Refereed)
    Abstract [en]

    Liner scattering of low frequency waves by an orifice plate has been studied using Large Eddy Simulation and an acoustic two-port model. The results have been compared to measurements with good agreement for waves coming from the downstream side. For waves coming from the upstream side the reflection is over-predicted, indicating that not enough of the acoustic energy is converted to vorticity at the upstream edge of the plate. Furthermore, the sensitivity to the amplitude of the acoustic waves has been studied, showing difficulties to simultaneously keep the amplitude low enough for linearity and high enough to suppress flow noise with the relatively short times series available in LES.

  • 10.
    Allam, S.
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Åbom, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Cooling fan noise control using micro-perforates2012In: Int. Congr. Expos. Noise Control Eng., INTER-NOISE, 2012, p. 10434-10445Conference paper (Refereed)
    Abstract [en]

    Baffle or split silencers are commonly used, e.g., in HVAC systems and as inlet/outlet silencers on gas turbines. Another application is to reduce noise from the cooling fan inlet for large IC-engines. A baffle silencer can be seen as a periodic arrangement of parallel rectangular absorbers which can be placed in a rectangular duct. The noise reduction afforded by parallel baffles depends not only on the physical properties of the lining, but also upon the angle of incidence of the sound waves impinging and the baffle length. In this paper the potential of using baffles made of Micro-Perforated Panels is investigated in particular with the cooling fan inlet application in mind. Theoretical models for the damping is derived and used to design optimum configurations. The models are based on the wave propagation in a periodic array of baffles so that only one period can be investigated in order to find the different modes. In particular the least attenuated mode is important to find in order to optimize the behavior. An important aspect is the inner structure of the MPP baffle, i.e., can it just be an empty air volume or to what extent must internal waves be prevented by putting in walls. From a stiffness point of view some inner walls might also be needed to avoid vibration problems. Due to these complexities the theoretical models are only presented for the simplest cases. In order to validate the models and to get a more complete test of different designs experiments were also carried out. During these experiments the effect of flow was also tested.

  • 11. Allam, S.
    et al.
    Åbom, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Investigation of aerodynamic installation effects for an axial fan2013In: 19th AIAA/CEAS Aeroacoustics Conference, 2013Conference paper (Refereed)
    Abstract [en]

    The aim of the work reported in this paper is to investigate the aerodynamic installation effects for a generic cooling fan system. This is done by treating the ducted fan as a multi-port source and performing a source characterization, i.e., determining the source strength and source reflection matrix. From the source strength, which represents the sound radiated by the fan in a reflexion free (infinite) duct, the effect of various inflow distortions can be studied. The work is part of the EU-project ECOQUEST where the data will be used to validate the acoustic prediction tools.

  • 12.
    Allam, Sabry
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Knutsson, M.
    Bodén, Hans
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Development of acoustic models for high frequency resonators for turbocharged IC-engines2012In: SAE Technical Paper 2012-01-1559, 2012, 2012Conference paper (Refereed)
    Abstract [en]

    Automotive turbo compressors generate high frequency noise in the air intake system. This sound generation is of importance for the perceived sound quality of luxury cars and may need to be controlled by the use of silencers. The silencers usually contain resonators with slits, perforates and cavities. The purpose of the present work is to develop acoustic models for these resonators where relevant effects such as the effect of a realistic mean flow on losses and 3D effects are considered. An experimental campaign has been performed where the two-port matrices and transmission loss of sample resonators have been measured without flow and for two different mean flow speeds. Models for two resonators have been developed using 1D linear acoustic theory and a FEM code (COMSOL Multi-physics). For some resonators a separate linear 1D Matlab code has also been developed. Different models, from the literature, for including the effect of mean flow on the acoustic losses at slits and perforates have been implemented in the codes and compared to the experimental data. Correct modeling of acoustic losses for resonators with complicated geometry is important for the simulation and development of new and improved silencers, and the present work contributes to this understanding. The developed models give acceptable agreement with the measured results even with flow but can be improved for 3D FEM if correct CAD data is available. The 1D linear theory can be used for simple geometries and to get a general overview related to the resonance frequencies and damping level.

  • 13.
    Allam, Sabry
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Åbom, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Acoustic modelling and characterization of plate heat exchangers2012In: SAE Technical Paper 2012-01-1562, Society of Automotive Engineers, 2012Conference paper (Refereed)
    Abstract [en]

    There is increased concern about the noise emission from cooling systems. This is mainly due to an increased need for cooling needs due to turbo-charging and EGR systems, which tend to increase the fan power and thereby the noise. An important issue in this context is the behavior of the heat-exchanger and its acoustic transmission and absorption properties. In this paper an acoustic model to evaluate such data for a common type of heat exchanger, the parallel plate type, is presented. The basic configuration is assumed to be a matrix of parallel, narrow channels. The developed model is based on a so called equivalent fluid for an anisotropic medium. It is mainly dependent on the heat exchanger geometry combined with the Kirchhoff model for thermo-viscous wave propagation in narrow tubes. The proposed model can be used to predict the sound transmission and absorption for an entire heat exchanger for incident plane waves. This model is validated by comparison with measurement results for seven different heat exchangers used in vehicle and train cooling units at different flow speeds

  • 14.
    Allam, Sabry
    et al.
    Helwan University, Cairo, Egypt.
    Åbom, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Fan Noise Control Using Microperforated Splitter Silencers2014In: Journal of Vibration and Acoustics-Transactions of the ASME, ISSN 1048-9002, E-ISSN 1528-8927, Vol. 136, no 3, p. 031017-Article in journal (Refereed)
    Abstract [en]

    Splitter or baffle silencers are commonly used, for example, in heating ventilation and air conditioning (HVAC) systems and as inlet/outlet silencers on gas turbines. Another application is to reduce noise from the cooling fan inlet for large IC-engines. A splitter silencer can be seen as a periodic arrangement of parallel rectangular absorbers, which can be placed in a rectangular duct. The noise reduction afforded by parallel splitters depends not only on the physical properties of the lining but also upon the angle of incidence of the impinging sound waves, and the splitter and duct dimensions. In this paper, the potential of using splitters made of microperforated plates (MPPs) is investigated, with a particular focus on cooling fan inlet/outlet applications.

  • 15.
    Allam, Sabry
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Åbom, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Noise control for cooling fans on heavy vehicles2012In: Noise Control Engineering Journal, ISSN 0736-2501, E-ISSN 2168-8710, Vol. 60, no 6, p. 707-715Article in journal (Refereed)
    Abstract [en]

    In this paper two different objects for fan passive noise control have been examined: heat exchangers and inlet/outlet parallel splitter silencers based on micro-perforated panels. The first object is theoretically and experimentally examined while the second is only examined experimentally. Throughout this paper two measurement methods were used. The ISO 15186-1:2000 to test the acoustic transmission for a diffuse field and plane wave testing in a duct of a sample cut from each heat exchanger type. Based on an anisotropic equivalent fluid model a theoretical model for the heat exchanger acoustic transmission is presented. A new type of splitter silencers based on micro-perforated plates, which can add damping up 10-20 dB in the frequency range of interest (<5 kHz), are also presented.

  • 16.
    Andersson, Martin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS.
    Baltzopoulos, Apostolos
    Lööf, Hans
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS.
    R & D strategies and entrepreneurial spawning2012In: Research Policy, ISSN 0048-7333, E-ISSN 1873-7625, Vol. 41, no 1, p. 54-68Article in journal (Refereed)
    Abstract [en]

    This paper analyzes how different R&D strategies of incumbent firms affect the quantity and quality of their entrepreneurial spawning. When examining entrepreneurial ventures of ex-employees of firms with different R&D strategies, three things emerge: First, firms with persistent R&D investments and a general superiority in sales, exports, productivity, profitability and wages are less likely to generate entrepreneurs than firms with temporary or no R&D investments. Second, start-ups from knowledge intensive business service (KIBS) firms with persistent R&D investments have a significantly increased probability of survival. No corresponding association between the R&D strategies of incumbents and survival of entrepreneurial spawns is found for incumbents in manufacturing sectors. Third, spin-outs from KIBS-firms are more likely to survive if they start in the same sector, indicating the importance of inherited knowledge. These findings suggest that R&D intensive firms are less likely to generate employee start-ups, but their entrepreneurial spawns tend to be of higher quality.

  • 17. Andersson, Martin
    et al.
    Johansson, B.
    Karlsson, Charlie
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Entrepreneurship and innovation. KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS.
    Lööf, Hans
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Entrepreneurship and innovation. KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS.
    Introduction2013In: Innovation and Growth: From R&D Strategies of Innovating Firms to Economy-wide Technological Change, Oxford University Press , 2013Chapter in book (Other academic)
  • 18.
    Andersson, Martin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS.
    Johansson, Börje
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Economics (Closed (20130101). KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS.
    Heterogeneous Distributions of Firms Sustained by Innovation Dynamics-A Model with Empirical Illustrations and Analysis2012In: Journal of Industry, Competition and Trade, ISSN 1566-1679, E-ISSN 1573-7012, Vol. 12, no 2, p. 239-263Article in journal (Refereed)
    Abstract [en]

    This paper develops a framework of innovation dynamics to appreciate observed heterogeneity of firm size distributions, in which dynamics refer to exit and entry of product varieties and variety markets of individual firms. The analysis is based on a model of variety-triplets where every such triplet in the economy is identified by a unique combination of a variety, destination and firm. New variety triplets are introduced by innovating firms in a quasi-temporal setting of monopolistic competition. Ideas for variety-triplets arrive to firms according to a firm-specific and state dependent Poisson process, whereas variety triplets exit according to a destination-specific Poisson process. The empirical analysis employs a detailed firm-level data base which provides information about all variety triplets. Firm size is measured by a firm's number of variety triplets. The empirical results are compatible with the model predictions of (i) a persistent distribution of firm sizes, (ii) frequent events of exit and entry, and (iii) state dependent entry, where a state may be given by each firm's composition of triplets and/or other firm attributes.

  • 19.
    Andersson, Martin
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301). KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS.
    Johansson, Börje
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301). KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS.
    Innovation Ideas and Regional Characteristics: product innovations and export entrepreneurship by firms in Swedish regions2008In: Growth and Change, ISSN 0017-4815, E-ISSN 1468-2257, Vol. 39, no 2, p. 193-224Article in journal (Refereed)
    Abstract [en]

    This paper focuses upon the ways in which characteristics of regions in regards to knowledge sources, communication opportunities, and absorptive capacity influence the development of innovation ideas among existing and potential entrepreneurs. We formulate a model where entrepreneurs or innovating firms introduce new products in a quasi-temporal setting. Market conditions are characterised by monopolistic competition between varieties belonging to the same product group, in which there is entry and exit of varieties. A stochastic process is assumed to generate new innovation ideas as time goes by, and a firm (entrepreneur) who receives such an idea has to transform the idea to an innovation, which in the model is specified as a particular variety combined with a specific destination market. The theoretical model is used as a reference when formulating two regression models, with which we estimate how a set of regional characteristics are associated with the likelihood of innovation ideas across Swedish local labour market regions. In one model, we examine the emergence of new export varieties, and in the second model, we investigate the appearance of new export firms. Results are consistent with the assumption that knowledge and information flows have a positive influence on the frequency of arrival of innovation ideas to firms.

  • 20. Andersson, Martin
    et al.
    Johansson, Börje
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.). Jönköping International Business School (JIBS), Sweden .
    Karlsson, Charlie
    KTH. Jönköping International Business School (JIBS), Sweden .
    Lööf, Hans
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.). KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS.
    Reflections2013In: Innovation and Growth: From R&D Strategies of Innovating Firms to Economy-wide Technological Change, Oxford University Press, 2013Chapter in book (Refereed)
  • 21.
    Andersson, Martin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS.
    Lööf, Hans
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Economics (Closed (20130101). KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS.
    Small business innovation: firm level evidence from Sweden2012In: Journal of Technology Transfer, ISSN 0892-9912, E-ISSN 1573-7047, Vol. 37, no 5, p. 732-754Article in journal (Refereed)
    Abstract [en]

    This paper examines innovation among very small firms and provides new insights into both internal and external determinants of patenting. Applying a non-linear panel data approach to about 160,000 observations on manufacturing firms in Sweden for the period 2000-2006, the following facts emerge: (i) in contrast to larger firms, innovation in micro firms with 1-10 employees is not sensitive to variation in internal financial resources, (ii) skilled labour is even more important for innovation among micro firms compared to other firms, (iii) affiliation to a domestically owned multinational enterprise group increases the innovation capacity of small businesses, (iv) small firms' innovation is closely linked to participation in international trade and exports to the G7-countries, and (v) there is no statistically significant evidence that proximity to metropolitan areas, or presence in a specialized cluster, increases the innovativeness of the smallest firm.

  • 22.
    Archenti, Andreas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Centres, Design and Management of Manufacturing Systems, DMMS. KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Nicolescu, Cornel Mihai
    KTH, School of Industrial Engineering and Management (ITM), Centres, Design and Management of Manufacturing Systems, DMMS. KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Evaluation of machining system dynamic stiffness2007In: Swedish Production Symposium: Gothenburg, Sweden, 2007, 2007Conference paper (Refereed)
    Abstract [en]

    Today’s test methods are analysing machine tool specific characteristics but leaves out to a great deal the machining process. In this paper an evaluation method for determining machining system dynamic characteristics is discussed. For machine capability analysis, the overall elastic structure must be considered, i.e., machine tool – fixture – workpiece – toolholder – tool. Regarding dynamic behaviour of machining systems, the stability can only be evaluated through the interaction between the two subsystems, elastic structure and cutting process. In order to analyse the join machining system, stochastic discrete models, ARMA models are used to identify the stability of the join system, elastic structure – machining process.

  • 23.
    Archenti, Andreas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Centres, Design and Management of Manufacturing Systems, DMMS. KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Nicolescu, Cornel Mihai
    KTH, School of Industrial Engineering and Management (ITM), Centres, Design and Management of Manufacturing Systems, DMMS. KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Evaluation of machining system static stiffness2007In: Swedish Production Symposium: Gothenburg, Sweden, 2007, 2007Conference paper (Refereed)
    Abstract [en]

    The majority of test methods used for determine a machining systems status, are machine tool oriented and do not take into consideration the characteristics of the machining process. In this paper an evaluation method for determining a machining system static characteristics are discussed. The importance of joint stiffness and damping in elastic structures of machine tool is emphasized. In this context the new type of double ball bar (DBB) is described which applies a preload on the structure, thus creating more realistic conditions for accuracy measurements. Also, for machine capability analysis, the overall elastic structure must be considered, i.e., machine tool-fixture-workpiece-tool holder-tool.

  • 24. Backman, Mikaela
    et al.
    Palmberg, Johanna
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS.
    Contextualizing small family firms: How does the urban-rural context affect firm employment growth?2015In: The Journal of Family Business Strategy, ISSN 1877-8585, E-ISSN 1877-8593, Vol. 6, no 4, p. 247-258Article in journal (Refereed)
    Abstract [en]

    This paper studies the effects of family governance and ownership on firm employment growth, extending existing knowledge by including in the analysis the regional context in which firms are located. We create a regional taxonomy to capture the urban-rural dimension and combine this with the corporate governance structure of the firm. Our results show that, being a family firm per se does not influence employment growth. However, when corporate governance structure and regional context are combined, the urban-rural context influences family firm and nonfamily firm employment growth differently, with family firms exhibiting greater employment growth, compared with nonfamily firms, in rural areas.

  • 25.
    Baltzopoulos, Apostolos
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    Broström, Anders
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.). KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS.
    Attractors of Entrepreneurial Activity: Universities, Regions and Alumni Entrepreneurs2013In: Regional studies, ISSN 0034-3404, E-ISSN 1360-0591, Vol. 47, no 6, p. 934-949Article in journal (Refereed)
    Abstract [en]

    Baltzopoulos A. and Brostrom A. Attractors of entrepreneurial activity: universities, regions and alumni entrepreneurs, Regional Studies. This paper investigates how universities may affect regional entrepreneurship through the localization decisions of entrepreneurial alumni. Empirically, a comprehensive, individual-level data set from Sweden for the period 2003-2005 is employed. The results suggest that even when controlling for their spatial history, individuals have an increased propensity to set up in the region where they studied. This effect is found to substitute for both urbanization economies and localization economies as drivers of regional-level entrepreneurship. Thus, the present analysis provides evidence on how universities affect regional economic development that complements the strong focus on spin-off activities by university researchers in previous studies.

  • 26.
    Basir, Nada
    et al.
    Schulich School of Business, York University, Canada.
    Beyhaghi, Mehdi
    College of Business, University of Texas at San Antonio, USA.
    Mohammadi, Ali
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Entrepreneurship and innovation. KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS.
    The Fate of Patents: An Exploratory Analysis of Patents as Signals of Reputational Advantage2013Report (Refereed)
    Abstract [en]

    Drawing on the reputation literature and signaling theory, this article builds on work that looks at patents as reputation signals.We build a multi-industry database of patents that expire due to lack of maintenance fee payments and test for a relationship between these patents and the firm’s IPO date.We find a significant and positive relationship between the likelihood of patents expiring due to lack of maintenance fee payments and the time to IPO. We also find that patents associated with firms which are not venture capital backed,are more likely to expire. Our findings suggest that patents that are used for signaling intentions are more likely to be underutilized.Implications for research and policy are discussed.

  • 27.
    Beyhaghi, Mehdi
    et al.
    The U. of Texas at San Antonio .
    Mahmoodi, Babak
    Mohammadi, Ali
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Entrepreneurship and innovation. KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS.
    Adverse Selection and Search Frictions in Corporate Loan Contracts2014Conference paper (Refereed)
    Abstract [en]

    We provide empirical evidence of both (1) price dispersion and (2) credit rationing in the corporate loan market. We argue that these properties are caused by two factors: an adverse selection resulting from the information asymmetry between lenders and borrowers, and search frictions in matching borrowers with lenders. We develop a model of loan markets in which lenders post an array of heterogeneous contracts, then borrowers tradeoff terms of loan contracts and matching probability between themselves. We show that a unique separating equilibrium exists where each type of borrower applies to a certain type of contract.

  • 28.
    Bhat, Sriharsha
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics. KTH, School of Industrial Engineering and Management (ITM), Centres, Integrated Transport Research Lab, ITRL.
    An Investigation into the Optimal Control Methods in Over-actuated Vehicles: With focus on energy loss in electric vehicles2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As vehicles become electrified and more intelligent in terms of sensing, actuation and processing; a number of interesting possibilities arise in controlling vehicle dynamics and driving behavior. Over-actuation with inwheel motors, all wheel steering and active camber is one such possibility, and can facilitate control combinations that push boundaries in energy consumption and safety. Optimal control can be used to investigate the best combinations of control inputs to an over-actuated system. In Part 1, a literature study is performed on the state of art in the field of optimal control, highlighting the strengths and weaknesses of different methods and their applicability to a vehicular system. Out of these methods, Dynamic Programming and Model Predictive Control are of particular interest. Prior work in overactuation, as well as control for reducing tire energy dissipation is studied, and utilized to frame the dynamics, constraints and objective of an optimal control problem. In Part 2, an optimal control problem representing the lateral dynamics of an over-actuated vehicle is formulated, and solved for different objectives using Dynamic Programming. Simulations are performed for standard driving maneuvers, performance parameters are defined, and a system design study is conducted. Objectives include minimizing tire cornering resistance (saving energy) and maintaining the reference vehicle trajectory (ensuring safety), and optimal combinations of input steering and camber angles are derived as a performance benchmark. Following this, Model Predictive Control is used to design an online controller that follows the optimal vehicle state, and studies are performed to assess the suitability of MPC to over-actuation. Simulation models are also expanded to include non-linear tires. Finally, vehicle implementation is considered on the KTH Research Concept Vehicle (RCV) and four vehicle-implementable control cases are presented.

    To conclude, this thesis project uses methods in optimal control to find candidate solutions to improve vehicle performance thanks to over-actuation. Extensive vehicle tests are needed for a clear indication of the energy saving achievable, but simulations show promising performance improvements for vehicles overactuated with all-wheel steering and active camber.

  • 29.
    Bhat, Sriharsha
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Davari, Mohammad Mehdi
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Nybacka, Mikael
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics. KTH, School of Industrial Engineering and Management (ITM), Centres, Integrated Transport Research Lab, ITRL.
    Study on energy loss due to cornering resistance in over-actuated electric vehicles using optimal control2017In: SAE International Journal of Vehicle Dynamics, Stability, and NVH - V126-10, 2017Conference paper (Refereed)
    Abstract [en]

    As vehicles become electrified and more intelligent in terms of sensing, actuation and processing; a number of interesting possibilities arise in controlling vehicle dynamics and driving behavior. Over-actuation with in- wheel motors, all wheel steering and active camber is one such possibility, which facilitate the control strategies that push boundaries in energy consumption and safety. Optimal control can be used to investigate the best combinations of control inputs to an over-actuated system. This paper shows how an optimal control problem can be formulated and solved for an over-actuated vehicle case, and highlights the translation of this optimal solution to a real-world scenario, enabling intelligent means to improve vehicle efficiency. This paper gives an insight into the Dynamic Programming (DP) as an offline optimal control method that guarantees the global optimum. Therefore the optimal control allocation to minimize an objective function and simultaneously fulfill the defined constraints can be achieved. As a case study the effect of over-actuation on the cornering resistance were investigated in two different maneuvers i.e. step steer and sine with dwell, where in both cases the vehicle assumes to be in steady state situation. In this work the cornering resistance is the main objective function and maintaining the reference trajectory is the constraint which should be fulfilled. A parameter study is conducted on the benefits of over-actuation, and depending on the type of over-actuation about 15% and 50% reduction in cornering resistance were observed during step steer and sine with dwell maneuver respectively. From a second parameter study that focused on COG position from a safety perspective, it is more beneficial for the vehicle to be designed to under-steer than over-steer. Finally, a method is described to translate the offline optimal results to vehicle implementable controllers in the form of both feed-through lookup-tables and rule-based feed-forward control.

  • 30.
    Bjerke, Lina
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS. Jönköping International Business School, Jönköping, Sweden.
    Karlsson, C.
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS.
    Metropolitan regions and export renewal2013In: Advances in Spatial Science, Springer International Publishing , 2013, p. 235-260Conference paper (Refereed)
    Abstract [en]

    Metropolitan regions are advantageous location for new export products due to factors such as external economies, diversified industry environment and a large share of skilled labour. This is the main assumption of this paper. What happens to these products when the technology becomes common knowledge? Using empirical data on exports, we find that products with a high specialisation in the metropolitan region have a tendency to be successful in the non-metropolitan regions subsequent years. Also, this export product diffusion does not seem to be related to a location in the immediate proximity to the metropolitan region. Instead, the recipient regions are mainly characterised as being centrally located in its labour market region, having a high share of highly educated individuals. Features related product standardisation such as a large manufacturing sector and low labour costs cannot be distinguished as prominent features.

  • 31.
    Bodin, Olle
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx). KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Wang, Yue
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Mihaescu, Mihai
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx). KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Fuchs, Laszlo
    KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx). KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    LES of the Exhaust Flow in a Heavy-Duty Engine2014In: Oil & gas science and technology, ISSN 1294-4475, E-ISSN 1953-8189, Vol. 69, no 1, p. 177-188Article in journal (Refereed)
    Abstract [en]

    The flow in the exhaust port and the exhaust manifold of a heavy-duty Diesel engine has been studied using the Large Eddy Simulation approach. Some of the flow characteristics in these components are: flow unsteadiness and separation combined with significant geometry-induced secondary flow motion. Detailed analysis of these features may add understanding which can be used to decrease the flow losses and increase the eciency of downstream components such as turbochargers and EGR coolers. Few LES studies of the flow in these components have been conducted in the past and this, together with the complexity of the flow are the motivations for this work. This paper shows that in the exhaust port, even global parameters like total pressure losses are handled better by LES than RANS. Flow structures of the type that afect both turbine performance and EGR cooler efficiency are generated in the manifold and these are found to vary significantly during the exhaust pulse. This paper also clearly illustrates the need to make coupled simulations in order to handle the complicated boundary conditions of these gas exchange components.

  • 32.
    Bodén, Hans
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Nonlinear source characterisation techniques for IC-engines2012In: 19th International Congress on Sound and Vibration 2012, ICSV 2012, 2012, p. 2442-2449Conference paper (Refereed)
    Abstract [en]

    A source characterization model for IC-engines, which can take weakly nonlinear source properties into account, is developed in the paper. It is based on so called polyharmonic distortion modeling, used for nonlinear characterization of microwave systems. Comparisons are made with the results from linear source models and another previously published weakly nonlinear source model. The results show that the new nonlinear impedance matrix model gives improvements in the prediction of sound pressure levels in the exhaust system.

  • 33.
    Bodén, Hans
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    The effect of speed variation on in-duct source data determination2014In: 21st International Congress on Sound and Vibration 2014, ICSV 2014, 2014, p. 2395-2401Conference paper (Refereed)
    Abstract [en]

    Experimental acoustic source characterization is used for IC-engines and fluid machines connected to duct or pipe systems. Information about the engine as an acoustic source is needed to calculate insertion loss of mufflers or the level of radiated sound. The source model used in the low frequency plane wave range is often the linear time invariant 1 -port model. The acoustic source data is obtained from experimental tests or from 1 -D CFD codes describing the engine gas exchange process. Multi-load methods and especially the two-load method are most commonly used to extract the source data. The IC-engine is a high level acoustic source and in most cases not completely linear. The real part of the measured source impedance sometimes has negative values which is un-physical. This effect has been attributed to non-linearity and source time variation. Another possible explanation could be speed variation giving measurement errors especially for higher harmonics. In the present paper this effect is studied by re-visiting source data experiments for IC-engine exhausts and comparing the outcome of different methods for extracting the amplitude and phase of the pressure in terms of frequency components or engine orders.

  • 34.
    Bodén, Hans
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Zhou, Lin
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    Acoustic Properties of an In-Duct Orifice Subjected to Bias Flow and High Level Acoustic Excitation2012In: Proceedings of the 10th International conference on Flow-Induced Vibration (& Flow-Induced Noise): FIV2012, Dublin, Ireland, 3-6 July 2012 FLOW-INDUCED VIBRATION, 2012, p. 187-193Conference paper (Refereed)
    Abstract [en]

    This paper experimentally investigates the acousticproperties of an orifice with bias flow under medium andhigh sound level excitation. The test included no bias flowand two bias speeds for three different frequencies. Experimentalresults are compared and discussed with theory.It is shown that bias flow makes the acoustic propertiesmuch more complex compared theory and with theno bias flow case, especially when velocity ratio betweenacoustic particle velocity and mean flow velocity is nearunity.

  • 35.
    Bodén, Hans
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Zhou, Lin
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).
    An experimental study of the effect of flow and high level acoustic excitation on the acoustic properties of perforates and orifices2013In: 20th International Congress on Sound and Vibration 2013, ICSV 2013: Volume 3, 2013, International Institute of Acoustics and Vibrations , 2013, p. 2545-2552Conference paper (Refereed)
    Abstract [en]

    Perforates are for instance used in mufflers for automotive applications and in acoustic liners for aircraft engines. In these applications they are often exposed to high level acoustic excitation in combination with grazing or bias flow. The paper is based on an experimental study of the nonlinear properties of these types of samples without mean grazing or bias flow as well as on a study of an orifice with bias flow under medium and high sound level excitation. The effect of grazing flow is discussed based on data from the literature. It is known from previous studies that high level acoustic excitation at one frequency will change the acoustic impedance of perforates at other frequencies, thereby changing the boundary condition seen by the acoustic waves. This effect could be used to change the impedance boundary conditions and for instance increase the absorption. It could obviously also pose a problem for the correct modeling of sound transmission through ducts lined with such impedance surfaces. Experimental results are compared to a quasi-stationary model. The effect of the combination of frequency components and phase in the excitation signal is studied. The bias flow tests included different flow speeds for different frequencies. The level of acoustic excitation is varied from much smaller to larger than the mean flow velocity. It is shown that bias flow makes the acoustic properties more complex compared to the no bias flow case, especially when the velocity ratio between acoustic particle velocity and mean flow velocity is near unity.

  • 36. Bornhäll, A.
    et al.
    Johansson, D.
    Palmberg, Johanna
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS. Swedish Entrepreneurship Forum, Stockholm, Sweden.
    The capital constraint paradox in micro and small family and nonfamily firms2016In: Journal of Entrepreneurship and Public Policy, ISSN 2045-2101, E-ISSN 2045-211X, Vol. 5, no 1, p. 38-62Article in journal (Refereed)
    Abstract [en]

    Purpose – The purpose of this paper is to investigate the importance of the entrepreneur’s quest for independence and control over the firm for governance and financing strategies with a special focus on family firms and how they differ from nonfamily firms. Design/methodology/approach – The analysis is based on 1,000 telephone interviews with Swedish micro and small firms. The survey data are matched with firm-level data from the Bureau van Dijks database ORBIS. Findings – The analysis shows that independence is a prime motive for enterprises, statistically significantly more so for family owners. Family owners are more prone to use either their own savings or loans from family and are more reluctant to resort to external equity capital. Our results indicate a potential “capital constraint paradox”; there might be an abundance of external capital while firm growth is simultaneously constrained by a lack of internal funds. Research limitations/implications – The main limitation is that the study is based on cross-section data. Future studies could thus be based on longitudinal data. Practical implications – The authors argue that policy makers must recognize independence and control aversion as strong norms that guide entrepreneurial action and that micro- and small-firm growth would profit more from lower personal and corporate income taxes compared to policy schemes intended to increase the supply of external capital. Originality/value – The paper offers new insights regarding the value of independence and how it affects strategic decisions within the firm.

  • 37.
    Bout, Martijn
    KTH, School of Industrial Engineering and Management (ITM), Centres, Integrated Transport Research Lab, ITRL.
    A Head-Mounted Display to Support Remote Operators of Shared Automated Vehicles2017Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Automated driving systems will be severely challenged under the unpredictable conditions of mixed traffic. Consequently, some form of human support remains essential in the foreseeable future. This challenge is particularly true for Shared Automated Vehicles, as these vehicles will likely not include any human driver onboard. When a Shared Automated Vehicle encounters a situation it cannot handle, a remote human operator will be needed to intervene. The remote operator can help the passengers to continue their journey by resuming vehicle operations. This thesis has investigated whether using a Head-MountedDisplay in comparison to a computer display improves Situation Knowledge for remote operators of Shared Automated Vehicles. This research adopted a user-centered design approach to develop a Head-Mounted Display and computer display prototype. In one of the first studies on a Shared Automated Vehicle remote control interface, this thesis considered implicit measurements of Situation Knowledge and did not focus on performance indicators. In a userstudy, twelve participants were given the task to determine the reason why theShared Automated Vehicle had stopped based on pre-recorded driving scenarios.Strong qualitative evidence indicates that a Head-Mounted Display canprovide remote operators with improved Situation Knowledge in comparisonto computer displays. To deepen the understanding of the performance andSituation Knowledge for remote operators of Shared Automated Vehicles undervarious conditions further research is necessary. Future studies can extendknowledge by assessing different scenarios and tasks in a live remote controlsituation, and develop and evaluate additional interface elements.

  • 38.
    Bout, Martijn
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Centres, Integrated Transport Research Lab, ITRL.
    Pernestål-Brenden, Anna
    KTH, School of Industrial Engineering and Management (ITM), Centres, Integrated Transport Research Lab, ITRL.
    Klingegård, Maria
    RISE Viktoria.
    Habibovic, Azra
    RISE Viktoria.
    Böckle, Marc-Philipp
    KTH, School of Industrial Engineering and Management (ITM), Centres, Integrated Transport Research Lab, ITRL.
    A Head-Mounted Display to Support Teleoperations of Shared Automated Vehicles2017In: AutomotiveUI 2017 - 9th International ACM Conference on Automotive User Interfaces and Interactive Vehicular Applications, Adjunct Proceedings, New York: ACM Digital Library, 2017, , p. 4p. 62-66Conference paper (Refereed)
    Abstract [en]

    Automated driving systems will be severely challenged in the unpredictable conditions of mixed traffic. Consequently, some form of human support remains essential in the foreseeable future. This challenge is especially true for Shared Automated Vehicles (SAVs), as these vehicles will likely not include any human driver on-board. When an SAV will encounter a scenario it cannot handle, a remote human operator will need to intervene and help the vehicle and its passengers. In this study a user-centred design approach is used to study whether a Head-Mounted Display (HMD) interface can support such operators and provide them with additional spatial awareness. Two prototypes (an HMD and a computer display) are developed and evaluated using pre-recorded real-world scenarios. Twelve participants assessed three possible scenarios a remote operator may encounter. Among participants, the study found evidence of strong implicit spatial awareness when using an HMD interface.

  • 39.
    Braunerhjelm, Pontus
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS. KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Economics.
    Academic Entrepreneurship: Social norms, university culture and policies2007Report (Other academic)
    Abstract [en]

    Is a shift in intellectual property rights to universities the key instrument in increasing com-mercialization of publicly funded research? How much can actually be learned from the U.S. system, disregarding the ongoing debate as to whether the U.S. do actually outperform Europe in terms of commercializing university based research? Taking Sweden as a role model I claim that this policy will not work. This allegation stems from the analysis of a unique data-base giving individual university researchers view on participation in commercialization of public research, their commercialization experiences, and the obstacles researchers claim exist to increase academic entrepreneurship. Despite researchers positive attitudes towards engag-ing in commercial activities, the university culture, weak incentive structures and badly man-aged support facilities impede the creation of efficient links to markets. I conclude that meas-ures must be taken at primarily the national level, but also at the university level, to enhance commercialization activities.

  • 40.
    Braunerhjelm, Pontus
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS. KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Economics.
    Entrepreneurship, Innovation and Economic Growth - past experience, current knowledge and policy implications2010Report (Other academic)
    Abstract [en]

    Considerable advances, even breakthroughs, have been made during the last decades in our understanding of the relationship between knowledge and growth on one hand, and entrepreneurship and growth on the other. Similarly, more profound insights have also been gained as to how entrepreneurship, innovation and knowledge are interrelated. Yet, a comprehensive understanding is still lacking concerning the interface of all of those variables: knowledge, innovation, entrepreneurship and growth. The link between the micro-economic origin of growth and the macro-economic outcome is still too rudimentary modeled to grasp the full width of these complex and intersecting forces. The main objective of this paper is hence to shed light on recent advances in our understanding of the forces that underpin the creation of knowledge, its diffusion and commercialization through innovation, and the role of the entrepreneur in the growth process. The policy implications of recent research findings conclude this survey. Particularly important policy implications refer to the design of regulation influencing knowledge production, ownership, entry barriers, labor mobility and (inefficient) financial markets. They all have implication for the efficient diffusion of knowledge through entry. Knowledge creation has to be matched by incentives that induce mechanisms to convert knowledge into societal and useful needs.

  • 41.
    Braunerhjelm, Pontus
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS. KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Economics.
    Entrepreneurship, Knowledge and Economic Growth2007Report (Other academic)
    Abstract [en]

    Knowledge plays a critical role in economic development, still our understanding of how knowledge is created, diffused and converted into growth, is fragmented and partial. The neoclassical growth models disregarded the entrepreneur and viewed knowledge as an exogenous factor. Contemporary current knowledge-based growth models have re-introduced the notion of the entrepreneur, however stripped of its most typical characteristics, and the diffusion of knowledge is kept exogenous. It implies that the predictions and policy conclusions derived from these models may be flawed. This paper reviews the literature that addresses the issues of knowledge creation, knowledge diffusion and growth, and the role attributed the entrepreneur in such dynamic processes. I will explore how these insights can be integrated into existing growth models and suggest a more thorough microeconomic foundations from which empirically testable hypotheses can be derived.

  • 42.
    Braunerhjelm, Pontus
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS. KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Economics.
    Madonna and the Music MiracleThe genesis and evolution of a globally competitive cluster2005Report (Other academic)
    Abstract [en]

    The issue addressed in this paper concerns the emergence and dynamics of a regional cluster inthe music industry. Whereas mainstream economic geography models explain agglomeration ofexisting economic activities, an evolutionary approach is necessary to understand the emergenceof genuinely new clusters. Based on an empirical analysis of the major Swedish music cluster, itis shown how cognitive features, the institutional and organizational framework, as well aseconomic incentives, were interlinked in the process of cluster emergence. A multitude of forcesthus coincided in time and space to support the emerging music cluster. A latent knowledge base,language skill and path-dependence all played a significant role. It is also shown how mobile anddensely located agents, displaying a high degree of connectivity, together with external impulsesthrough immigrants, contributed to the dynamics and re-vitalization of the Stockholm musiccluster.

  • 43.
    Braunerhjelm, Pontus
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS. KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Economics.
    REGIONAL SPECIALIZATION AND UNIVERSITIES: THENEW VERSUS THE OLD2006Report (Other academic)
    Abstract [en]

    This paper analyzes the impact universities have on regional development and as to whether adifference can be detected between the influence of the old and new universities. To achievethis end a unique dataset on the researchers’ view regarding the universities role in commercialization,distinguishing between new universities (established around 1970) and old universities(established in the 15th and 17th century), is initially utilized. In the subsequent stagespatially disaggregated data is implemented in a two-step Heckman regression analysis to examinewhether a relationship exists between the universities research specialization and regionalproduction specialization 1975 to 1999. The results reveal that there are considerabledifferences across universities, albeit primarily unrelated to the age of the universities. Finally,the impact of universities on regional productivity in knowledge-based industries is examined.

  • 44.
    Braunerhjelm, Pontus
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS. KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Economics.
    Specialization of Regions and Universities The New Versus the Old2007Report (Other academic)
    Abstract [en]

    This paper analyzes whether there is a correspondence between a university’s research spe-cialization and industrial specialization in the region hosting the university, and to what extent universities influences regional productivity. Moreover, the analysis seeks to answer if a dif-ference can be detected between the influences of old and new universities on regional per-formance. To achieve this end we utilize a unique dataset on spatially disaggregated data for Sweden in the period 1975-1999. A two-step Heckman regression analysis is implemented to examine whether the universities research specialization match regional specialization in pro-duction as compared to the average region. The results suggest a correspondence in speciali-zation, as well as positive productivity effects. However, there are also considerable differ-ences across regions, albeit primarily unrelated to the age of the universities.

  • 45.
    Braunerhjelm, Pontus
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS. KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Economics.
    Acs, Zoltan
    Audretsch, David
    Carlsson, Bo
    The Knowledge Spillover Theory of Entrepreneurship2006Report (Other academic)
    Abstract [en]

    Contemporary theories of entrepreneurship generally focus on the recognition of opportunities and the decision to exploit them. While the prevailing view in the entrepreneurship literature is that opportunities are exogenous, the most prevalent theory of economic growth suggests that opportunities are endogenous. This paper bridges the gap between the entrepreneurship and economic growth literatures by developing a knowledge spillover theory of entrepreneurship. Knowledge created endogenously results in knowledge spillovers that give rise to opportunities to be identified and exploited by entrepreneurs.

  • 46.
    Braunerhjelm, Pontus
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS. KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Economics.
    Andersson, Martin
    Thulin, Per
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS. KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Economics.
    Creative Destruction and Productivity: Entrepreneurship by type, sector and sequence2011Report (Other academic)
    Abstract [en]

    Schumpeter claimed the entrepreneur to be instrumental for creative destruction and industrial dynamics. Entrepreneurial entry serves to transform and revitalize industries, thereby enhancing their competiveness. This paper investigates if entry of new firms influences productivity amongst incumbent firms, and the extent to which altered productivity can be attributed sector and time specific effects. Implementing a unique dataset we estimate a firm-level production function in which the productivity of incumbent firms is modeled as a function of firm attributes and regional entrepreneurship activity. The analysis finds support for positive productivity effects of entrepreneurship on incumbent firms, albeit the effect varies over time, what we refer to as a delayed entry effect. An immediate negative influence on productivity is followed by a positive effect several years after the initial entry. Moreover, the productivity of incumbent firms in services sectors appears to be more responsive to regional entrepreneurship, as compared to the productivity of manufacturing firms.

  • 47.
    Braunerhjelm, Pontus
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Economics. KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS.
    Baltzopoulos, Apostolos
    Tikoudis, Ioannis
    Spin-off: Individual, Firm, Industry and Regional Determinants2012Report (Other academic)
    Abstract [en]

    The extent and importance of spin-offs for industrial dynamics have been analysed in a number of previous studies, yet knowledge is surprisingly scarce about the determinants that trigger such entrepreneurial ventures. In the current analysis we use unique and detailed Swedish data to comprehensively explore how individual, firm, regional, and industry variables influence spin-offs during 1999-2005. In addition to the expected general positive impact of regional size and entrepreneurial culture, we find specific features for knowledge intensive manufacturing and service production on the propensity of employees to spin off a new venture. Moreover, we use an entropy measure to disentangle unrelated and related variety, and find that the former has a significantly negative impact while the latter a significantly positive effect on the propensity of the individual to start a spin-off.

  • 48.
    Braunerhjelm, Pontus
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS. KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Economics (Closed (20130101).
    Birkinshaw, Julian
    Holm, Ulf
    Terjesen, Siri
    WHY DO SOME MULTINATIONAL CORPORATIONS RELOCATE THEIR HEADQUARTERS OVERSEAS?2006Report (Other academic)
    Abstract [en]

    This paper examines the decision by a multinational corporation (MNC) to relocate itsbusiness unit and/or corporate HQ overseas. We argue that business unit HQs move overseasin response to changes in the internal configuration of their unit’s activities and the demandsof the product markets in which they operate, whereas corporate HQs move overseas isresponse to the demands of external stakeholders, in particular global financial markets andshareholders. Using data on 125 business unit HQs and 35 corporate HQs, we test and findsupport for these arguments. The research highlights important differences betweencorporate- and business-level strategy, and it suggests ways in which the theory of the MNCneeds to be reconsidered.

  • 49.
    Braunerhjelm, Pontus
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS. KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Economics.
    Borgman, Benny
    Agglomeration, Diversity and Regional Growth: The effects of poly-industrial versus mono-industrial agglomerations2006Report (Other academic)
    Abstract [en]

    The objective of this paper is to empirically examine the importance of the structure of agglomeration on productivity and growth. To accomplish this we will include the degree of co-agglomeration of similar industries as an explanatory variable in the empirical analysis, while simultaneously controlling for the degree of industry-specific agglomeration. To the best of our knowledge, the impact of co-agglomerated industries on productivity has not previously been investigated. The empirical analysis confirms a positive statistical relationship between interdependent and co-located industries on labour productivity.

  • 50.
    Braunerhjelm, Pontus
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Centres, Centre of Excellence for Science and Innovation Studies, CESIS. KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Economics.
    Borgman, Benny
    Entrepreneurship and Local Growth: A comparison of the U.S. and Sweden2007Report (Other academic)
    Abstract [en]

    The U.S. is traditionally viewed as an economy driven by entrepreneurs, whereas the Swedish model is associated with high welfare ambitions and less focus on entrepreneurial activities. This paper seeks to empirically investigate whether the connection between entrepreneurship and growth at the regional level differs between the U.S. and Sweden. By regressing annual entrepreneurship on regional employment growth (and controlling for other conceivable variables impacting employment growth) entrepreneurship is shown to be positively and significantly associated with regional growth in both countries in the 1990s. Still, the result is more robust for the U.S. Other important variables for regional growth is business density and, in the case of the U.S., educational levels and internal scale economies.

1234567 1 - 50 of 393
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