5,042 research outputs found

    Technology strategy and innovation: the use of derivative strategies in the aerospace industry

    Get PDF
    Strategy has become an increasingly important theme within the management of innovation. This is reflected in the increasing amount of attention given to topics such as technology strategy within the innovation literature. However research into technology strategy has tended to focus on technology acquisition rather than technology exploitation. This paper focuses on one often neglected way in which companies can exploit the technological resources at their disposal, namely through the use of a derivative strategy where new technology is combined with old products or parts of old products in order to develop new products. The paper explores this type of strategy by means of a case study from the commercial jet engine sector of the aerospace industry. The case study provides an opportunity not only to explore the nature of derivative strategies in detail it also highlights the benefits, both direct and indirect, to be gained from this type of strategy as a means of exploiting an organisation's technological resources. The paper shows how a derivative strategy can contribute to the broader strategic goals of companies in technology based industries through strategies designed to ensure the most effective utilisation of the technology base

    Global data for ecology and epidemiology: a novel algorithm for temporal Fourier processing MODIS data

    Get PDF
    Background. Remotely-sensed environmental data from earth-orbiting satellites are increasingly used to model the distribution and abundance of both plant and animal species, especially those of economic or conservation importance. Time series of data from the MODerate-resolution Imaging Spectroradiometer (MODIS) sensors on-board NASA's Terra and Aqua satellites offer the potential to capture environmental thermal and vegetation seasonality, through temporal Fourier analysis, more accurately than was previously possible using the NOAA Advanced Very High Resolution Radiometer (AVHRR) sensor data. MODIS data are composited over 8- or 16-day time intervals that pose unique problems for temporal Fourier analysis. Applying standard techniques to MODIS data can introduce errors of up to 30% in the estimation of the amplitudes and phases of the Fourier harmonics. Methodology/Principal Findings. We present a novel spline-based algorithm that overcomes the processing problems of composited MODIS data. The algorithm is tested on artificial data generated using randomly selected values of both amplitudes and phases, and provides an accurate estimate of the input variables under all conditions. The algorithm was then applied to produce layers that capture the seasonality in MODIS data for the period from 2001 to 2005. Conclusions/Significance. Global temporal Fourier processed images of 1 km MODIS data for Middle Infrared Reflectance, day- and night-time Land Surface Temperature (LST), Normalised Difference Vegetation Index (NDVI), and Enhanced Vegetation Index (EVI) are presented for ecological and epidemiological applications. The finer spatial and temporal resolution, combined with the greater geolocational and spectral accuracy of the MODIS instruments, compared with previous multi-temporal data sets, mean that these data may be used with greater confidence in species' distribution modelling

    An Active-shunt Diverter for On-load Tap Changers

    Get PDF
    This paper presents a new hybrid diverter design for on-load tap changers. The design uses “active-shunt” current diversion principles. At its core, the design employs a low-voltage high-current switch-mode amplifier to divert current out of the mechanical contacts and into a pair of anti-parallel thyristors. Commutation between transformer taps may then be performed by the thyristors. The amplifier and thyristors are placed outside the normal load current path and only conduct during a tap change, producing efficiency savings and improving robustness when compared to previous hybrid on-load tap changer implementations. An amplifier control loop that autonomously produces zero-current conditions at switch opening and zero-voltage conditions at switch closure is demonstrated. Experimental results investigating the wear characteristics of contacts operated under the new hybrid diverter are presented, along with comparison results from a passive-type switching scheme. Contact lifetime of more than 25 million operations is demonstrated under the new scheme

    A low-wear onload tap changer diverter switch for frequent voltage control on distribution networks

    Get PDF

    A novel seven-level active neutral-point-clamped converter with reduced active switching devices and DC-link voltage

    Get PDF
    © 1986-2012 IEEE. This paper presents a novel seven-level inverter topology for medium-voltage high-power applications. It consists of eight active switches and two inner flying capacitor (FC) units forming a similar structure as in a conventional active neutral-point-clamped (ANPC) inverter. This unique arrangement reduces the number of active and passive components. A simple modulation technique reduces cost and complexity in the control system design without compromising reactive power capability. In addition, compared to major conventional seven-level inverter topologies, such as the neutral point clamped, FC, cascaded H-bridge, and ANPC topologies, the new topology reduces the dc-link voltage requirement by 50%. This recued dc-link voltage makes the new topology appealing for various industrial applications. Experimental results from a 2.2-kVA prototype are presented to support the theoretical analysis presented in this paper. The prototype demonstrates a conversion efficiency of around 97.2% ± 1% for a wide load range

    Why be down in the mouth? Three decades of research in oral microbiology

    Get PDF
    The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher's copy is included.This paper describes some of the work done in the author's laboratory over the past 35 years. The research covers the following areas: the physiology of oral streptococci and their interactions; the physiology of some Gram-negative anaerobes and their interactions in relation to periodontal diseases; preventing the major dental diseases; and the future of oral microbiology.AH Roger

    The role of the microbiome in mucosal inflammation.

    Get PDF
    The microbiome plays an important role in maintaining human health. Despite multiple factors being attributed to the shaping of the human microbiome, extrinsic factors such diet and use of medications including antibiotics appear to dominate. Mucosal surfaces, particularly in the gut, are highly adapted to be able to tolerate a large population of microorganisms while still being able to produce a rapid and effective immune response against infection. The intestinal microbiome is not functionally independent from the host mucosa and can, through presentation of microbe-associated molecular patterns and generation of microbial-derived metabolites, fundamentally influence mucosal barrier integrity and modulate host immunity. In a healthy gut there is an abundance of beneficial bacteria that help to preserve intestinal homeostasis, promote protective immune responses and limit excessive inflammation. The importance of the microbiome is further highlighted during dysbiosis where a loss of this finely-balanced microbial population can lead to mucosal barrier dysfunction, aberrant immune responses, and chronic inflammation that increases the risk of disease development. Improvements in our understanding of the microbiome are providing opportunities to harness members of a healthy microbiome to help reverse dysbiosis, reduced inflammation and ultimately prevent disease progression

    Conditional Sampling for Max-Stable Processes with a Mixed Moving Maxima Representation

    Full text link
    This paper deals with the question of conditional sampling and prediction for the class of stationary max-stable processes which allow for a mixed moving maxima representation. We develop an exact procedure for conditional sampling using the Poisson point process structure of such processes. For explicit calculations we restrict ourselves to the one-dimensional case and use a finite number of shape functions satisfying some regularity conditions. For more general shape functions approximation techniques are presented. Our algorithm is applied to the Smith process and the Brown-Resnick process. Finally, we compare our computational results to other approaches. Here, the algorithm for Gaussian processes with transformed marginals turns out to be surprisingly competitive.Comment: 35 pages; version accepted for publication in Extremes. The final publication is available at http://link.springer.co
    corecore