100 research outputs found

    Collision Avoidance Law Using Information Amount

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    Multi-Robot Patrol Algorithm with Distributed Coordination and Consciousness of the Base Station's Situation Awareness

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    Multi-robot patrolling is the potential application for robotic systems to survey wide areas efficiently without human burdens and mistakes. However, such systems have few examples of real-world applications due to their lack of human predictability. This paper proposes an algorithm: Local Reactive (LR) for multi-robot patrolling to satisfy both needs: (i)patrol efficiently and (ii)provide humans with better situation awareness to enhance system predictability. Each robot operating according to the proposed algorithm selects its patrol target from the local areas around the robot's current location by two requirements: (i)patrol location with greater need, (ii)report its achievements to the base station. The algorithm is distributed and coordinates the robots without centralized control by sharing their patrol achievements and degree of need to report to the base station. The proposed algorithm performed better than existing algorithms in both patrolling and the base station's situation awareness.Comment: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

    Self-assembled Artificial Viral Capsid Decorated with Gold Nanoparticles

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    The decoration of a peptide-based artificial viral capsid with gold nanoparticles (AuNPs) is reported. β-Annulus GGGCG-bearing peptide as a binding site of AuNPs self-assembled into nanocapsules with a diameter of 50 nm. The addition of AuNPs to the peptide nanocapsules afforded relatively uncontrolled assemblies of AuNPs. In contrast, the self-assembly of AuNP−peptide conjugates afforded, after dialysis, controlled assemblies of AuNPs with sizes of 30−60 nm. ζ-Potential measurements revealed that the surface of the artificial viral capsid self-assembled from β-annulus peptide was coated with AuNPs

    Current Spike Reduction Technique for High Power Laser Diode Driver with Pulse Current Output

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    A Vertical-Cavity Surface-Emitting Laser (VCSEL) has attracted a strong interest as a pump source of diode pumped solid state (DPSS) lasers for many applications, such as welding, cutting and marking, in recent years. In the past, a series dropper has been typically used as a laser driver. However, the power loss of series dropper which adopts several kW class high power laser is very large, and the cooling system becomes much larger and whole driver is also much larger. In order to solve these problems, switch mode power supply (SMPS) is adopted as a laser driver. However, switch device breakdown problem occurs in this case. This paper clarifies the mechanism of mentioned above problem and proposes the solution technique.2017 IEEE 12th International Conference on Power Electronics & Drive Systems, Hawaii convention center, Honolulu, USA, 12-15 December 201

    〈Original Papers〉Diurnal and seasonal variation of air temperature profile in the mountain forest at Sugadaira, central Japan

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    Air temperature profiles were observed for a year with micro-climate observation in and around the mixed mountain forest. The shading effects of tree crown, depending on the solar elevation angle and abscission of broad leaf species, controlled the diurnal and seasonal variation of radiation budget and temperature gradients in the forest. Vertical mixing of air in the forest was infrequent even the wind speed over the forest was high. Sasa albo-marginata served as another important daytime heat source at the forest floor in snow-free season. In the forest, weak but clear diurnal wind variation was observed on fair summer days indicating prevailing of daytime up-slope winds and nocturnal gravity currents. After leaf abscission, the nocturnal temperature inversion prevailed in and out of the forest. The importance of the local winds blowing through the forest and their effect on the data from the station in an open space are discussed with regard to the long-term assessment of mountain meteorological and forest phonological data

    Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

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    We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012

    SHISA6 Confers Resistance to Differentiation-Promoting Wnt/β-Catenin Signaling in Mouse Spermatogenic Stem Cells

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    In the seminiferous tubules of mouse testes, a population of glial cell line-derived neurotrophic factor family receptor alpha 1 (GFRα1)-positive spermatogonia harbors the stem cell functionality and supports continual spermatogenesis, likely independent of asymmetric division or definitive niche control. Here, we show that activation of Wnt/β-catenin signaling promotes spermatogonial differentiation and reduces the GFRα1+ cell pool. We further discovered that SHISA6 is a cell-autonomous Wnt inhibitor that is expressed in a restricted subset of GFRα1+ cells and confers resistance to the Wnt/β-catenin signaling. Shisa6+ cells appear to show stem cell-related characteristics, conjectured from the morphology and long-term fates of T (Brachyury)+ cells that are found largely overlapped with Shisa6+ cells. This study proposes a generic mechanism of stem cell regulation in a facultative (or open) niche environment, with which different levels of a cell-autonomous inhibitor (SHISA6, in this case) generates heterogeneous resistance to widely distributed differentiation-promoting extracellular signaling, such as WNTs

    Precise Measurement of the Neutrino Mixing Parameter theta(23) from Muon Neutrino Disappearance in an Off-Axis Beam

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    New data from the T2K neutrino oscillation experiment produce the most precise measurement of the neutrino mixing parameter theta_{23}. Using an off-axis neutrino beam with a peak energy of 0.6 GeV and a data set corresponding to 6.57 x 10^{20} protons on target, T2K has fit the energy-dependent nu_mu oscillation probability to determine oscillation parameters. Marginalizing over the values of other oscillation parameters yields sin^2 (theta_{23}) = 0.514 +0.055/-0.056 (0.511 +- 0.055), assuming normal (inverted) mass hierarchy. The best-fit mass-squared splitting for normal hierarchy is Delta m^2_{32} = (2.51 +- 0.10) x 10^{-3} eV^2/c^4 (inverted hierarchy: Delta m^2_{13} = (2.48 +- 0.10) x 10^{-3} eV^2/c^4). Adding a model of multinucleon interactions that affect neutrino energy reconstruction is found to produce only small biases in neutrino oscillation parameter extraction at current levels of statistical uncertainty

    Measurement of the intrinsic electron neutrino component in the T2K neutrino beam with the ND280 detector

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    The T2K experiment has reported the first observation of the appearance of electron neutrinos in a muon neutrino beam. The main and irreducible background to the appearance signal comes from the presence in the neutrino beam of a small intrinsic component of electron neutrinos originating from muon and kaon decays. In T2K, this component is expected to represent 1.2% of the total neutrino flux. A measurement of this component using the near detector (ND280), located 280 m from the target, is presented. The charged current interactions of electron neutrinos are selected by combining the particle identification capabilities of both the time projection chambers and electromagnetic calorimeters of ND280. The measured ratio between the observed electron neutrino beam component and the prediction is 1.01 +/- 0.10 providing a direct confirmation of the neutrino fluxes and neutrino cross section modeling used for T2K neutrino oscillation analyses. Electron neutrinos coming from muons and kaons decay are also separately measured, resulting in a ratio with respect to the prediction of 0.68 +/- 0.30 and 1.10 +/- 0.14, respectively
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