1,981 research outputs found

    Business models: An empirical approach to firm structures and organisational change

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    Popular though poorly-defined, the business model construct has generated a fragmented and non-accretive research literature. Despite prominence in the practice community for scholarly research has yet to converge on construct boundaries or establish a research framework in organizational theory. This study develops an integrative approach to business models and identifies business model formation and change processes. Prior studies address business models within the strategy discourse of competitive positioning. The failure to disentangle business models and strategy has limited theoretical and practical research. A quasi-systematic review of the academic literature combined with a discourse analysis of the business model in practice yields an empirical assessment of business model language. Managers use business models to address opportunities rather than position the firm for competitive advantage. This anchors an integrative definition for the business model as the design of organizational structures to enact an opportunity. Building on this framework, an analysis of structured interviews with 556 large firm CEOs establishes the links between organizational structures and strategic flexibility. Working within a capabilities and structural framework, the study extends research on strategic flexibility firms engaged in business model innovation in a global, cross-industry context. Creative culture enables strategic flexibility while partner dependence inhibits it. In addition, firms that focus managerial attention without giving up non-core activities achieve flexible outcomes. Finally, a case-based study of innovative entrepreneurial firms unpacks characteristics of business model formation and change processes. In contrast to theories of outward-facing strategic fit with environment, entrepreneurial firms undergo an internallydriven process towards business model coherence. The case studies reveal a self-evolving narrative process operating at multiple levels within the firm. The application of a narrative framework facilitates a novel sense-making approach to theories of change at entrepreneurial firms

    Predicting the response of a submillimeter bolometer to cosmic rays

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    Bolometers designed to detect. submillimeter radiation also respond to cosmic, gamma, and x rays. Because detectors cannot be fully shielded from such energy sources, it is necessary to understand the effect of a photon or cosmic-ray particle being absorbed. The resulting signal (known as a glitch) can then be removed from raw data. We present measurements using an Americium-241 gamma radiation source to irradiate a prototype bolometer for the High Frequency Instrument in the Planck Surveyor satellite. Our measurements showed no variation in response depending on where the radiation was absorbed, demonstrating that the bolometer absorber and thermistor thermalize quickly. The bolometer has previously been fully characterized both electrically and optically. We find that using optically measured time constants underestimates the time taken for the detector to recover from a radiation absorption event. However, a full thermal model for the bolometer, with parameters taken from electrical and optical measurements, provides accurate time constants. Slight deviations from the model were seen at high energies; these can be accounted for by use of an extended model

    Planck 2015 results. VIII. High Frequency Instrument data processing: Calibration and maps

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    This paper describes the processing applied to the cleaned, time-ordered information obtained from the Planck High Frequency Instrument (HFI) with the aim of producing photometrically calibrated maps in temperature and (for the first time) in polarization. The data from the entire 2.5-year HFI mission include almost five full-sky surveys. HFI observes the sky over a broad range of frequencies, from 100 to 857 GHz. To obtain the best accuracy on the calibration over such a large range, two different photometric calibration schemes have been used. The 545 and 857 GHz data are calibrated using models of planetary atmospheric emission. The lower frequencies (from 100 to 353 GHz) are calibrated using the time-variable cosmological microwave background dipole, which we call the orbital dipole. This source of calibration only depends on the satellite velocity with respect to the solar system. Using a CMB temperature of T_(CMB) = 2.7255 ± 0.0006 K, it permits an independent measurement of the amplitude of the CMB solar dipole (3364.3 ± 1.5 ÎŒK), which is approximatively 1σ higher than the WMAP measurement with a direction that is consistent between the two experiments. We describe the pipeline used to produce the maps ofintensity and linear polarization from the HFI timelines, and the scheme used to set the zero level of the maps a posteriori. We also summarize the noise characteristics of the HFI maps in the 2015 Planck data release and present some null tests to assess their quality. Finally, we discuss the major systematic effects and in particular the leakage induced by flux mismatch between the detectors that leads to spurious polarization signal

    Planck 2015 results. I. Overview of products and scientific results

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    The European Space Agency’s Planck satellite, which is dedicated to studying the early Universe and its subsequent evolution, was launched on 14 May 2009. It scanned the microwave and submillimetre sky continuously between 12 August 2009 and 23 October 2013. In February 2015, ESA and the Planck Collaboration released the second set of cosmology products based ondata from the entire Planck mission, including both temperature and polarization, along with a set of scientific and technical papers and a web-based explanatory supplement. This paper gives an overview of the main characteristics of the data and the data products in the release, as well as the associated cosmological and astrophysical science results and papers. The data products include maps of the cosmic microwave background (CMB), the thermal Sunyaev-Zeldovich effect, diffuse foregrounds in temperature and polarization, catalogues of compact Galactic and extragalactic sources (including separate catalogues of Sunyaev-Zeldovich clusters and Galactic cold clumps), and extensive simulations of signals and noise used in assessing uncertainties and the performance of the analysis methods. The likelihood code used to assess cosmological models against the Planck data is described, along with a CMB lensing likelihood. Scientific results include cosmological parameters derived from CMB power spectra, gravitational lensing, and cluster counts, as well as constraints on inflation, non-Gaussianity, primordial magnetic fields, dark energy, and modified gravity, and new results on low-frequency Galactic foregrounds
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