39,022 research outputs found

    Competition, Innovation and Increasing Returns

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    This paper concerns the operation of competition in the presence of a high rate of innovation and increasing returns. Given free competition there is likely to exist, in this case, a tendency towards what may be called ‘dynamic equilibrium’, a tendency, that is to say, for the rate of investment in product development to rise or fall towards the level at which this investment yields only a normal return. Thus, competition, increasing returns and innovation may co-exist.Innovation, increasing returns, competition

    Economic Analysis, Public Policy and the Software Industry

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    This paper focuses on three related matters. It analyses the process of competition in the software industry, this being important both in itself and for the light it throws on competition within all industries characterised by low or zero marginal costs and a high rate of technical development. The software industry, operating under private enterprise, is dependent on copyright, and the issues raised by intellectual property protection are therefore also considered. Given the need for inter-operability between different software products, and between these and associated hardware, standardisation is important within the industry, and the processes by which standards may be established are evaluated. Consideration is given to the public policy issues that are raised by these three topics.Software, competition, innovation, standardisation, intellectual property protection

    An analytic model of plasma-neutral coupling in the heliosphere plasma

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    We have developed an analytic model to describe coupling of plasma and neutral fluids in the partially ionized heliosphere plasma medium. The sources employed in our analytic model are based on a κ\kappa-distribution as opposed to the Maxwellian distribution function. Our model uses the κ\kappa-distribution to analytically model the energetic neutral atoms that result in the heliosphere partially ionized plasma from charge exchange with the protons and subsequently produce a long tail which is otherwise not describable by the Maxwellian distribution. We present our analytic formulation and describe major differences in the sources emerging from these two distinct distributions.Comment: This paper has been accepted in Journal of Plasma Physics. It is in pres

    Reconfiguration based built-in self-test for analogue front-end circuits

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    Previous work has shown that it is feasible to implement a fully digital test evaluation function to realise partial self-test on an automatic gain control circuit (AGC). This paper extends the technique to INL, DNL, offset & gain error testing of analogue to digital converters (ADC's). It also shows how the same function can be used to test an AGC / ADC pair. An extension to full self-test is also proposed by the on-chip generation of input stimuli through reconfiguration of existing functions

    Epidemiology and economic impact of Johne's disease in Irish dairy herds

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    End of project reportThis project addressed two aspects of an emerging infectious disease of Irish cattle; the epidemiology and the economic impacts of Johne’s disease (paratuberculosis). Though this disease has been present in Irish cattle herds for decades, only since the introduction of the Single European Market in 1992 has it become more widespread. In addition to this change in the epidemiology of the disease in Irish cattle, there is increasing evidence that the causative organism, Mycobacterium avium subsp. paratuberculosis (MAP) may be implicated in a human illness, Crohn’s disease, though proof of a zoonotic link is currently disputed (Tremblay, 2004). Against this background a collaborative research project was set up by Teagasc and funded by Irish dairy farmers

    Parameter estimates for fractional autoregressive spatial processes

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    A binomial-type operator on a stationary Gaussian process is introduced in order to model long memory in the spatial context. Consistent estimators of model parameters are demonstrated. In particular, it is shown that d^Nd=OP((LogN)3N)\hat{d}_N-d=O_P(\frac{(\operatorname {Log}N)^3}{N}), where d=(d1,d2)d=(d_1,d_2) denotes the long memory parameter.Comment: Published at http://dx.doi.org/10.1214/009053605000000589 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Time management situation assessment (TMSA)

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    TMSA is a concept prototype developed to support NASA Test Directors (NTDs) in schedule execution monitoring during the later stages of a Shuttle countdown. The program detects qualitative and quantitative constraint violations in near real-time. The next version will support incremental rescheduling and reason over a substantially larger number of scheduled events

    Conformal Field Theory and the Exact Solution of the BCS Hamiltonian

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    We propose a connection between conformal field theory (CFT) and the exact solution and integrability of the reduced BCS model of superconductivity. The relevant CFT is given by the SU(2)kSU(2)_k-WZW model in the singular limit when the level k goes to -2. This theory has to be perturbed by an operator proportional to the inverse of the BCS coupling constant. Using the free field realization of this perturbed Wess-Zumino-Witten model, we derive the exact Richardson's wave function and the integrals of motion of the reduced BCS model in the saddle point approximation. The construction is reminiscent of the CFT approach to the Fractional Quantum Hall effect.Comment: 10 pages, RevTe

    Partitioning of carbon dioxide between the atmosphere and lithosphere on early Mars

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    It is pointed out that in addition to the 1 to 5 bar CO2 total inventory, a high level of global volcanism was needed to keep the CO2 from being drawn away permanently by weathering of igneous rocks; the volcanism would continually decompose the carbonate resulting in steady efficient recycling
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