354 research outputs found

    A prescriptive approach to qualify and quantify customer value for value-based requirements engineering

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    Recently, customer-based product development is becoming a popular paradigm. Customer expectations and needs can be identified and transformed into requirements for product design with the help of various methods and tools. However, in many cases, these models fail to focus on the perceived value that is crucial when customers make the decision of purchasing a product. In this paper, a prescriptive approach to support value-based requirements engineering (RE) is proposed, describing the foundations, procedures and initial applications in the context of RE for commercial aircraft. An integrated set of techniques, such as means-ends analysis, part-whole analysis and multi-attribute utility theory is introduced in order to understand customer values in depth and width. Technically, this enables identifying the implicit value, structuring logically collected statements of customer expectations and performing value modelling and simulation. Additionally, it helps to put in place a system to measure customer satisfaction that is derived from the proposed approach. The approach offers significant potential to develop effective value creation strategies for the development of new product

    The Atomic Physics Underlying the Spectroscopic Analysis of Massive Stars and Supernovae

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    We have developed a radiative transfer code, CMFGEN, which allows us to model the spectra of massive stars and supernovae. Using CMFGEN we can derive fundamental parameters such as effective temperatures and surface gravities, derive abundances, and place constraints on stellar wind properties. The last of these is important since all massive stars are losing mass via a stellar wind that is driven from the star by radiation pressure, and this mass loss can substantially influence the spectral appearance and evolution of the star. Recently we have extended CMFGEN to allow us to undertake time-dependent radiative transfer calculations of supernovae. Such calculations will be used to place constraints on the supernova progenitor, to place constraints on the supernova explosion and nucleosynthesis, and to derive distances using a physical approach called the "Expanding Photosphere Method". We describe the assumptions underlying the code and the atomic processes involved. A crucial ingredient in the code is the atomic data. For the modeling we require accurate transition wavelengths, oscillator strengths, photoionization cross-sections, collision strengths, autoionization rates, and charge exchange rates for virtually all species up to, and including, cobalt. Presently, the available atomic data varies substantially in both quantity and quality.Comment: 8 pages, 2 figures, Accepted for publication in Astrophysics & Space Scienc

    Correction to: The relevance of the interpersonal theory of suicide for predicting past-year and lifetime suicidality in autistic adults (Molecular Autism, (2022), 13, 1, (14), 10.1186/s13229-022-00495-5)

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    Following publication of the original article [1], the authors reported missing information in the ‘Acknowledgements’ section. The corrected ‘Acknowledgements’ section reads: We thank our participants for their generosity in taking part in the present research and for their helpful feedback towards this and future research. We would like to thank the ACORN panel at Bournemouth University for the funding this research, and our supportive colleagues. Special thanks goes to Rebecca Ellis for her patience in assisting with participant payments. We thank our colleagues at the Autism Research Centre who helped us recruit through their participant panel; the staff at Autistica who allowed us to advertise to their research network; moderators and owners of Facebook groups who were willing to let us advertise our study. Dr. Moseley thanks Dr. Sarah George, Dr. Helen Bolderston, and Dr. CĂ©cile Bardon for their advice around ensuring the safety of participants, with especial thanks to Dr. Bardon for her warm encouragement. Finally, the authors remember all autistic people whose lives were lost to suicide, both within our participant cohort and the broader autistic community. The original article [1] has been updated

    Donor states in modulation-doped Si/SiGe heterostructures

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    We present a unified approach for calculating the properties of shallow donors inside or outside heterostructure quantum wells. The method allows us to obtain not only the binding energies of all localized states of any symmetry, but also the energy width of the resonant states which may appear when a localized state becomes degenerate with the continuous quantum well subbands. The approach is non-variational, and we are therefore also able to evaluate the wave functions. This is used to calculate the optical absorption spectrum, which is strongly non-isotropic due to the selection rules. The results obtained from calculations for Si/Si1−x_{1-x}Gex_x quantum wells allow us to present the general behavior of the impurity states, as the donor position is varied from the center of the well to deep inside the barrier. The influence on the donor ground state from both the central-cell effect and the strain arising from the lattice mismatch is carefully considered.Comment: 17 pages, 10 figure

    Whole genome analysis of a schistosomiasis-transmitting freshwater snail

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    Biomphalaria snails are instrumental in transmission of the human blood fluke Schistosoma mansoni. With the World Health Organization's goal to eliminate schistosomiasis as a global health problem by 2025, there is now renewed emphasis on snail control. Here, we characterize the genome of Biomphalaria glabrata, a lophotrochozoan protostome, and provide timely and important information on snail biology. We describe aspects of phero-perception, stress responses, immune function and regulation of gene expression that support the persistence of B. glabrata in the field and may define this species as a suitable snail host for S. mansoni. We identify several potential targets for developing novel control measures aimed at reducing snail-mediated transmission of schistosomiasis
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