1,261 research outputs found

    On ringeisen's isolation game

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    AbstractWe develop the theory of the Isolation Game on a graph G, in which two players alternately “switch” at successive vertices v not previously switched. The switching operation deletes all edges incident with v, and creates new edges between v and those vertices not previously adjacent to it. The game is won when a vertex is first isolated. Among other results, we show that n-vertex forced wins exist for all n, and that length-p forced wins exist for all p. We give generic examples of forced wins which (against best defense) can be won only very late in the game. We also prove several large classes of graphs to be unwinnable, and give a complexity results for a problem closely related to the identification of drawing strategies in In(G)

    A middleware for a large array of cameras

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    Large arrays of cameras are increasingly being employed for producing high quality image sequences needed for motion analysis research. This leads to the logistical problem with coordination and control of a large number of cameras. In this paper, we used a lightweight multi-agent system for coordinating such camera arrays. The agent framework provides more than a remote sensor access API. It allows reconfigurable and transparent access to cameras, as well as software agents capable of intelligent processing. Furthermore, it eases maintenance by encouraging code reuse. Additionally, our agent system includes an automatic discovery mechanism at startup, and multiple language bindings. Performance tests showed the lightweight nature of the framework while validating its correctness and scalability. Two different camera agents were implemented to provide access to a large array of distributed cameras. Correct operation of these camera agents was confirmed via several image processing agents

    Women Engineers: A Study Of Educational Preparation And Professional Success

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    In an effort to better understand the educational experiences and professional issues facing women in these fields, a survey of women alumnae was conducted. Respondents seemed fairly pleased with the education they received and were heavily influenced by personal aspects of the campus. Relationships with faculty members were described as their most beneficial and detrimental experiences. They particularly liked opportunities to apply their technical knowledge but did not believe there were enough opportunities for application. The need for more female role models and importance of involvement in student organizations were cited by many of the respondents. Self‐confidence and good communication skills were rated as the most important qualities for professional success and advancement. Alumnae have pursued training experiences since graduation but would like to see more opportunities to enhance communication and personal management skills and apply theoretical knowledge built into the undergraduate experience. The findings are discussed in relationship to previous research studies and recommendations are made to improve the technically oriented college environment. 1993 American Society for Engineering Educatio

    Causes of breakage and disruption in a homogeniser

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    Many authors have written in the past regarding the exact causes of breakage and disruption in a high pressure homogeniser, but there has been little agreement. This paper investigates some of the most likely causes of the rupture of the walls of unicellular organisms and offers suggestions obtained from various papers and work carried out

    Extending standard testing period in honeybees to predict lifespan impacts of pesticides and heavy metals using dynamic energy budget modelling

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    Concern over reported honeybee (Apis mellifera spp.) losses has highlighted chemical exposure as a risk. Current laboratory oral toxicity tests in A. mellifera spp. use short-term, maximum 96 hour, exposures which may not necessarily account for chronic and cumulative toxicity. Here, we use extended 240 hour (10 day) exposures to examine seven agrochemicals and trace environmental pollutant toxicities for adult honeybees. Data were used to parameterise a dynamic energy budget model (DEBtox) to further examine potential survival effects up to 30 day and 90 day summer and winter worker lifespans. Honeybees were most sensitive to insecticides (clothianidin > dimethoate ≫ tau-fluvalinate), then trace metals/metalloids (cadmium, arsenic), followed by the fungicide propiconazole and herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). LC50s calculated from DEBtox parameters indicated a 27 fold change comparing exposure from 48 to 720 hours (summer worker lifespan) for cadmium, as the most time-dependent chemical as driven by slow toxicokinetics. Clothianidin and dimethoate exhibited more rapid toxicokinetics with 48 to 720 hour LC50s changes of <4 fold. As effects from long-term exposure may exceed those measured in short-term tests, future regulatory tests should extend to 96 hours as standard, with extension to 240 hour exposures further improving realism

    Cosmological Parameters Degeneracies and Non-Gaussian Halo Bias

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    We study the impact of the cosmological parameters uncertainties on the measurements of primordial non-Gaussianity through the large-scale non-Gaussian halo bias effect. While this is not expected to be an issue for the standard LCDM model, it may not be the case for more general models that modify the large-scale shape of the power spectrum. We consider the so-called local non-Gaussianity model and forecasts from planned surveys, alone and combined with a Planck CMB prior. In particular, we consider EUCLID- and LSST-like surveys and forecast the correlations among fNLf_{\rm NL} and the running of the spectral index αs\alpha_s, the dark energy equation of state ww, the effective sound speed of dark energy perturbations cs2c^2_s, the total mass of massive neutrinos Mν=∑mνM_\nu=\sum m_\nu, and the number of extra relativistic degrees of freedom NνrelN_\nu^{rel}. Neglecting CMB information on fNLf_{\rm NL} and scales k>0.03hk > 0.03 h/Mpc, we find that, if NνrelN_\nu^{\rm rel} is assumed to be known, the uncertainty on cosmological parameters increases the error on fNLf_{\rm NL} by 10 to 30% depending on the survey. Thus the fNLf_{\rm NL} constraint is remarkable robust to cosmological model uncertainties. On the other hand, if NνrelN_\nu^{\rm rel} is simultaneously constrained from the data, the fNLf_{\rm NL} error increases by ∼80\sim 80%. Finally, future surveys which provide a large sample of galaxies or galaxy clusters over a volume comparable to the Hubble volume can measure primordial non-Gaussianity of the local form with a marginalized 1--σ\sigma error of the order ΔfNL∼2−5\Delta f_{\rm NL} \sim 2-5, after combination with CMB priors for the remaining cosmological parameters. These results are competitive with CMB bispectrum constraints achievable with an ideal CMB experiment.Comment: 17 pages, 1 figure added, typos corrected, comments added, matches the published versio
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