9,749 research outputs found

    Air transport in Africa: toward sustainable business models for African airlines

    Get PDF
    Although there is a vast amount of literature on airline business models and their evolution in changing global landscapes, there is a general lack of research into the applicability of those models, traditionally defined in European and North American contexts, to the African scene. Implicit in this study is the hypothesis that the African environment is unique enough to warrant its own host of strategies, which may be distinctive enough to form part of a new strategic template, or business model. Initially, a review of existing literature is undertaken to profile the African aviation environment and evaluate existing airline business models and their evolution, both globally and in Africa. The methodology consists firstly of a cluster exercise, whereby 57 African airlines are analysed in terms of their network and size, to yield a number of heterogeneous groups which serve to identify the current business models of airlines on the continent. Following this, eight airlines (representative of the groups outlined in the cluster analysis) were subsequently selected for analysis in terms of the Product and Organisational Architecture framework. While it was evident that the traditional models are followed in Africa, in some instances variations were apparent. Full-service network carriers and regional carriers were concluded as being the most prominent and stable in the African market. The applicability of the low-cost carrier model in Africa was also examined at length, with mixed results. The analysis also raised network density and connectivity as essential components of business models for delivering profits in an African context

    Low-complexity LSMR equalisation of FrFT-based multicarrier systems in doubly dispersive channels

    Get PDF
    The discrete fractional Fourier transform (FrFT) has been suggested to enhance performance over DFT-based multicarrier systems when transmitting over doubly-dispersive channels. In this paper, we propose a novel low-complexity equaliser for inter-symbol and inter-carrier interference arising in such multicarrier transmission system. Due to a lower spreading in the FrFT-domain compared to the DFTchannel matrix as compared to the DFT domain, the equaliser cam approximate the fractional-domain channel matrix by a band matrix. Further, we utilise the least squares minres (LSMR) algorithm in the calculation of the equalisation, which exhibits attractive numerical properties and low complexity. Simulation results demonstrate the superior performance of the proposed LSMR equaliser over benchmark schemes

    Chirp-based multicarrier modulation

    Get PDF
    In this paper we demonstrate that in doubly-dispersive environments, a multicarrier (MC) system based on a fractional Fourier transform (FrFT) can achieve a better concentration of power near the main diagonal of the equivalent channel matrix compared to standard orthogonal frequency division multiplexing (OFDM). The resulting inter-symbol and inter-carrier interference in such a chirp- based MC system can therefore be suppressed with a reduced complexity equaliser. Simulations show that compared to an equalised OFDM system, the equalised FrFT-MC approach can either significantly reduce complexity or enhance performance in a time-varying environment

    ARE ASSESSMENTS FOR GENERIC ADVERTISING OPTIMAL IF PRODUCTS ARE DIFFERENTIATED?

    Get PDF
    An analytical framework where consumers display preferences for various qualities of an agricultural commodity is used to investigate the producer welfare effects of generic advertising assessments. Depending upon the degree of product differentiation present in the final goods, some producers are shown to benefit more than others from the use of an equivalent assessment on all producers. This paper delineates those cases where producer assessments should be equal and where assessments should be different to insure an equitable benefit.Marketing,

    Are Standards Always Protectionist?

    Get PDF
    We analyze the effects of a domestic standard that reduces an externality associated with the consumption of the good targeted by the standard, using a model in which foreign and domestic producers compete in the domestic good market. Producers can reduce expected damage associated with the externality by incurring a cost that varies by source of origin. Despite potential protectionism, the standard is useful in correcting the consumption externality in the domestic country. Protectionism occurs when the welfare-maximizing domestic standard is higher than the international standard maximizing welfare inclusive of foreign profits. The standard is actually anti-protectionist when foreign producers are much more efficient at addressing the externality than are domestic producers. Possible exclusion of domestic or foreign producers arises with large standards, which may alter the classification of a standard as protectionist or non-protectionist. The paper provides important implications for the estimation and use of tariff equivalents of nontariff barriers. JEL Classification Code: F13externality; nontariff barriers; protectionism; safety; standard; tariff equivalent

    Determinants of Foreign Direct Investment of South African Telecommunications Firms into Sub-Saharan Africa

    Get PDF
    The study investigates the main factors considered by South African telecommunications firms when making a decision to undertake Foreign Direct Investment (FDI) into Sub-Saharan Africa (SSA). This encompasses the reasons for investing, the methods of entry into the identified market and the factors influencing their decision. The methodology employs a survey questionnaire which was sent to telecommunication firms representing more than 70% of the revenue generated by this sector in SSA. The research reveals that market size, regulatory environment and government policy are the three most important factors influencing the decision to undertake FDI. Furthermore, the main reasons for deciding to enter SSA are for market and profit growth due to saturation in their existing markets, as well as for diversification of risk. Telecommunications firms wishing to enter SSA must be prepared for an unstable and uncertain policy environment and understand that the cost of starting a new venture in SSA is high.Telecommunications Africa FDI

    SOME ECONOMIC IMPLICATIONS OF PUBLIC LABELING

    Get PDF
    This article discusses economic issues related to public labeling. The main contributions in both the empirical and theoretical literatures are presented in order to motivate responses to the questions, when should a regulator promote public labeling, and what are the limits to and the possible market distortions from public labeling? Although the issues are complicated, there is already much economic guidance that can be given to inform the policy debate over food labeling.Agribusiness,

    Post-acquisition image based compensation for thickness variation in microscopy section series

    Full text link
    Serial section Microscopy is an established method for volumetric anatomy reconstruction. Section series imaged with Electron Microscopy are currently vital for the reconstruction of the synaptic connectivity of entire animal brains such as that of Drosophila melanogaster. The process of removing ultrathin layers from a solid block containing the specimen, however, is a fragile procedure and has limited precision with respect to section thickness. We have developed a method to estimate the relative z-position of each individual section as a function of signal change across the section series. First experiments show promising results on both serial section Transmission Electron Microscopy (ssTEM) data and Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) series. We made our solution available as Open Source plugins for the TrakEM2 software and the ImageJ distribution Fiji
    corecore