5,260 research outputs found

    NEW DIMENSIONS AND POTENTIALS FOR AID-UNIVERSITY COOPERATION

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    Research and Development/Tech Change/Emerging Technologies,

    Discovering Evolutionary Stepping Stones through Behavior Domination

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    Behavior domination is proposed as a tool for understanding and harnessing the power of evolutionary systems to discover and exploit useful stepping stones. Novelty search has shown promise in overcoming deception by collecting diverse stepping stones, and several algorithms have been proposed that combine novelty with a more traditional fitness measure to refocus search and help novelty search scale to more complex domains. However, combinations of novelty and fitness do not necessarily preserve the stepping stone discovery that novelty search affords. In several existing methods, competition between solutions can lead to an unintended loss of diversity. Behavior domination defines a class of algorithms that avoid this problem, while inheriting theoretical guarantees from multiobjective optimization. Several existing algorithms are shown to be in this class, and a new algorithm is introduced based on fast non-dominated sorting. Experimental results show that this algorithm outperforms existing approaches in domains that contain useful stepping stones, and its advantage is sustained with scale. The conclusion is that behavior domination can help illuminate the complex dynamics of behavior-driven search, and can thus lead to the design of more scalable and robust algorithms.Comment: To Appear in Proceedings of the Genetic and Evolutionary Computation Conference (GECCO 2017

    Surveying the Scope of the SU(2)_L Scalar Septet Sector

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    Extending the Standard Model by adding a scalar field transforming as a septet under SU(2)LSU(2)_L preserves the ρ\rho parameter at tree level and can satisfy experimental constraints on the electroweak parameters SS and TT. This work presents the first fully general phenomenological study of such an extension. We examine constraints on the septet model couplings based on electroweak and Higgs observables, and use LHC searches for new physics to bound the mass of the septet to be above 400\sim 400 GeV at a 95%95\% CL.Comment: pdfLateX, 17 pages, 6 figures, reference added. Version published in JHE

    Abundances of Disk Planetary Nebulae in M31 and the Radial Oxygen Gradient

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    We have obtained spectra of 16 planetary nebulae in the disk of M31 and determined the abundances of He, N, O, Ne, S and Ar. Here we present the median abundances and compare them with previous M31 PN disk measurements and with PNe in the Milky Way. We also derive the radial oxygen gradient in M31, which is shallower than that in the Milky Way, even accounting for M31's larger disk scale length.Comment: 2 pages, 1 figure, 1 table, to appear in the proceedings of IAU Symposium No. 283, Planetary Nebulae: An Eye to the Futur

    Abundances of PNe in the Outer Disk of M31

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    We present spectroscopic observations and chemical abundances of 16 planetary nebulae (PNe) in the outer disk of M31. The [O III] 4363 line is detected in all objects, allowing a direct measurement of the nebular temperature essential for accurate abundance determinations. Our results show that the abundances in these M31 PNe display the same correlations and general behaviors as Type II PNe in the Milky Way Galaxy. We also calculate photoionization models to derive estimates of central star properties. From these we infer that our sample PNe, all near the peak of the Planetary Nebula Luminosity Function, originated from stars near 2 M_sun. Finally, under the assumption that these PNe are located in M31's disk, we plot the oxygen abundance gradient, which appears shallower than the gradient in the Milky Way.Comment: 48 pages, including 12 figures and 8 tables, accepted by Astrophysical Journa

    A high-performance data structure for mobile information systems

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    Mobile information systems can now be provided on small form-factor computers. Dictionary-based data compression extends the capabilities of systems with limited processing and memory to enable data intensive applications to be supported in such environments. The nature of judicial sentencing decisions requires that a support system provides accurate and up-to-date data and is compatible with the professional working experience of a judge. The difficulties caused by mobility and the data dependence of the decision-making process are addressed by an Internet-based architecture for collecting and distributing system data.We describe an approach to dictionary-based data compression and the structure of an information system that makes use of this technology

    Importance of Baryon-Baryon Coupling in Hypernuclei

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    The ΛNΣN\Lambda N - \Sigma N coupling in Λ\Lambda--hypernuclei and ΛΛΞN\Lambda \Lambda - \Xi N coupling in ΛΛ\Lambda \Lambda--hypernuclei produce novel physics not observed in the conventional, nonstrange sector. Effects of ΛΣ\Lambda \leftrightarrow \Sigma conversion in Λ3^3_{\Lambda}H are reviewed. The role of ΛNΣN\Lambda N - \Sigma N coupling suppression in the A=4,5A=4,5 Λ\Lambda--hypernuclei due to Pauli blocking is highlighted, and the implications for the structure of   Λ10^{10}_{\;\, \Lambda}B are explored. Suppression of ΛΛΞN\Lambda \Lambda - \Xi N conversion in ΛΛ    6^{\;\;\, 6}_{\Lambda \Lambda}He is hypothesized as the reason that the matrix element is small. Measurement of ΛΛ    4^{\;\;\, 4}_{\Lambda \Lambda}H is proposed to investigate the full ΛΛΞN\Lambda \Lambda - \Xi N interaction. The implication for ΛΛ\Lambda \Lambda analog states is discussed.Comment: 17 pages LATEX, 1 figure uuencoded postscrip

    Researcher's guide to the NASA Ames Flight Simulator for Advanced Aircraft (FSAA)

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    Performance, limitations, supporting software, and current checkout and operating procedures are presented for the flight simulator, in terms useful to the researcher who intends to use it. Suggestions to help the researcher prepare the experimental plan are also given. The FSAA's central computer, cockpit, and visual and motion systems are addressed individually but their interaction is considered as well. Data required, available options, user responsibilities, and occupancy procedures are given in a form that facilitates the initial communication required with the NASA operations' group

    Coordinated egg production and marketing in the north central states V. Least-cost egg marketing organization under alternative production patterns

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    Important changes are taking place in the mid-western egg industry. Changes in Iowa are broadly representative of the transformations taking place in this industry throughout the region. One of the most significant changes has been the decline in the number of farms producing eggs. In 1940, 198,000 Iowa farms -or 93 percent of all farms-reported chickens on hand. In 1950, the number was 174,000, or 86 percent. By 1959, there had been a further decline to 68 percent. Along with the changing number of farms producing eggs, there has been a change in the sizes of flocks on farms. In Iowa, the proportion of very small flocks has remained nearly constant. In 1940 and 1950, roughly 13 percent of all Iowa flocks had fewer than 50 hens. This rose to about 15 percent in 1959. A sharp decline in medium-sized flocks of 50 to 400 hens occurred in the same period, from 86 percent in 1940 to 71 percent in 1959. Numbers of flocks larger than 400 hens have shown substantial increases, as shown in table 1 (1, 8, 14). Small flocks (less than 50 hens) are of little commercial importance. They are maintained mainly to supply the farm household with eggs for consumption. Farm flocks of 50 to 400 hens are most numerous; they have served as a means of acquiring a steady flow of cash for the household and an outlet for family labor on the family farm. For our study, flocks of this size take on great importance; they are the main component of the existing production pattern. Flocks larger than 400 hens are increasing rapidly and will probably continue to increase because of economies of scale in egg production and possible economies in marketing operations. This study emphasizes these larger flocks to ascertain their relationship to assembly and processing costs

    Firm growth processes and structural changes in the grain industries of the north central region

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    Growth is an important objective of the modern business enterprise. It is the means by which firms adjust to the environmental factors affecting their industries and individual operations. In turn, changes in firm size and organization, including entry and exit, determine the structural characteristics of a given industry at a given point in time. Although industry structure can be described statically, obviously growth processes leading to structural changes must be analyzed over time. This report uses several static and dynamic models to describe and analyze the process of structural change in the grain industries of the North Central Region. The general objective of this study was to determine the direction and magnitude of the major changes in firm organization and growth processes associated with the structural changes in the North Central Region (NCR) grain-marketing industry. More specifically, for each major type of firm ownership, each subindustry and the entire NCR grain industry, attempts were made to: (a) measure the changes in firm size and industry concentration, (b) classify these changes into basic components of specialization and diversification and (c) assess the relative importance of these components
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