8,046 research outputs found

    Software acquisition: a business strategy analysis

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    The paper argues that there are new insights to be gained from a strategic analysis of requirements engineering. The paper is motivated by a simple question: what does it take to be a world class software acquirer? The question has relevance for requirements engineers because for many organisations market pressures mean that software is commonly acquired rather than developed from scratch. The paper builds on the work of C. H. Fine (1998) who suggests that product, process and supply chain should be designed together, i.e., 3D concurrent engineering. Using a number of reference theories, it proposes a systematic way of carrying out 3D concurrent engineering. The paper concludes that the critical activity in supply chain design is the design of the distribution of skills and the nature of contract

    Universal Description of Granular Metals at Low Temperatures: Granular Fermi Liquid

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    We present a unified description of the low temperature phase of granular metals that reveals a striking generality of the low temperature behaviors. Our model explains the universality of the low-temperature conductivity that coincides exactly with that of the homogeneously disordered systems and enables a straightforward derivation of low temperature characteristics of disordered conductors.Comment: 4 pages, 1 figur

    Ferromagnetism of Weakly-Interacting Electrons in Disordered Systems

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    It was realized two decades ago that the two-dimensional diffusive Fermi liquid phase is unstable against arbitrarily weak electron-electron interactions. Recently, using the nonlinear sigma model developed by Finkelstein, several authors have shown that the instability leads to a ferromagnetic state. In this paper, we consider diffusing electrons interacting through a ferromagnetic exchange interaction. Using the Hartree-Fock approximation to directly calculate the electron self energy, we find that the total energy is minimized by a finite ferromagnetic moment for arbitrarily weak interactions in two dimensions and for interaction strengths exceeding a critical proportional to the conductivity in three dimensions. We discuss the relation between our results and previous ones

    Medicaid Crowd-Out of Private Long-Term Care Insurance Demand: Evidence from the Health and Retirement Survey

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    This paper provides empirical evidence of Medicaid crowd out of demand for private long-term care insurance. Using data on the near- and young-elderly in the Health and Retirement Survey, our central estimate suggests that a 10,000decreaseinthelevelofassetsanindividualcankeepwhilequalifyingforMedicaidwouldincreaseprivatelongtermcareinsurancecoverageby1.1percentagepoints.TheseestimatesimplythatifeverystateinthecountrymovedfromtheircurrentMedicaidasseteligibilityrequirementstothemoststringentMedicaideligibilityrequirementsallowedbyfederallawachangethatwoulddecreaseaveragehouseholdassetsprotectedbyMedicaidbyabout10,000 decrease in the level of assets an individual can keep while qualifying for Medicaid would increase private long-term care insurance coverage by 1.1 percentage points. These estimates imply that if every state in the country moved from their current Medicaid asset eligibility requirements to the most stringent Medicaid eligibility requirements allowed by federal law – a change that would decrease average household assets protected by Medicaid by about 25,000 – demand for private long-term care insurance would rise by 2.7 percentage points. While this represents a 30 percent increase in insurance coverage relative to the baseline ownership rate of 9.1 percent, it also indicates that the vast majority of households would still find it unattractive to purchase private insurance. We discuss reasons why, even with extremely stringent eligibility requirements, Medicaid may still exert a large crowd-out effect on demand for private insurance.

    Are Bosonic Replicas Faulty?

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    Motivated by the ongoing discussion about a seeming asymmetry in the performance of fermionic and bosonic replicas, we present an exact, nonperturbative approach to zero-dimensional replica field theories belonging to the broadly interpreted "beta=2" Dyson symmetry class. We then utilise the formalism developed to demonstrate that the bosonic replicas do correctly reproduce the microscopic spectral density in the QCD inspired chiral Gaussian unitary ensemble. This disproves the myth that the bosonic replica field theories are intrinsically faulty.Comment: 4.3 pages; final version to appear in PR

    Fine-grain process modelling

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    In this paper, we propose the use of fine-grain process modelling as an aid to software development. We suggest the use of two levels of granularity, one at the level of the individual developer and another at the level of the representation scheme used by that developer. The advantages of modelling the software development process at these two levels, we argue, include respectively: (1) the production of models that better reflect actual development processes because they are oriented towards the actors who enact them, and (2) models that are vehicles for providing guidance because they may be expressed in terms of the actual representation schemes employed by those actors. We suggest that our previously published approach of using multiple “ViewPoints” to model software development participants, the perspectives that they hold, the representation schemes that they deploy and the process models that they maintain, is one way of supporting the fine-grain modelling we advocate. We point to some simple, tool-based experiments we have performed that support our proposition

    Renormalization of hole-hole interaction at decreasing Drude conductivity

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    The diffusion contribution of the hole-hole interaction to the conductivity is analyzed in gated GaAs/Inx_xGa1x_{1-x}As/GaAs heterostructures. We show that the change of the interaction correction to the conductivity with the decreasing Drude conductivity results both from the compensation of the singlet and triplet channels and from the arising prefactor αi<1\alpha_i<1 in the conventional expression for the interaction correction.Comment: 6 pages, 5 figure

    Derivation of the Quantum Probability Rule without the Frequency Operator

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    We present an alternative frequencists' proof of the quantum probability rule which does not make use of the frequency operator, with expectation that this can circumvent the recent criticism against the previous proofs which use it. We also argue that avoiding the frequency operator is not only for technical merits for doing so but is closely related to what quantum mechanics is all about from the viewpoint of many-world interpretation.Comment: 12 page

    Using Classical Probability To Guarantee Properties of Infinite Quantum Sequences

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    We consider the product of infinitely many copies of a spin-121\over 2 system. We construct projection operators on the corresponding nonseparable Hilbert space which measure whether the outcome of an infinite sequence of σx\sigma^x measurements has any specified property. In many cases, product states are eigenstates of the projections, and therefore the result of measuring the property is determined. Thus we obtain a nonprobabilistic quantum analogue to the law of large numbers, the randomness property, and all other familiar almost-sure theorems of classical probability.Comment: 7 pages in LaTe
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