914 research outputs found

    Fuzzy Support Vector Machine-based Multi-agent Optimal Path

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    A mobile robot to navigate purposefully from a start location to a target location, needs three basic requirements: sensing, learning, and reasoning. In the existing system, the mobile robot navigates in a known environment on a predefined path. However, the pervasive presence of uncertainty in sensing and learning, makes the choice of a suitable tool of reasoning and decision-making that can deal with incomplete information, vital to ensure a robust control system. This problem can be overcome by the proposed navigation method using fuzzy support vector machine (FSVM). It proposes a fuzzy logic-based support vector machine (SVM) approach to secure a collision-free path avoiding multiple dynamic obstacles. The navigator consists of an FSVM-based collision avoidance. The decisions are taken at each step for the mobile robot to attain the goal position without collision. Fuzzy-SVM rule bases are built, which require simple evaluation data rather than thousands of input-output training data. The effectiveness of the proposed method is verified by a series of simulations and implemented with a microcontroller for navigation.Defence Science Journal, 2010, 60(4), pp.387-391, DOI:http://dx.doi.org/10.14429/dsj.60.49

    Design optimization of deflection caused after release of multilayer structural membrane of Symmetric Toggle Switch

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    This paper presents the optimization in deflection caused by the inbuilt stress generated in mechanical or movable membrane of Symmetric Toggle RF MEMS Switch (STS). The movable membrane of STS was initially fabricated with two different materials, i.e. Chrome and Gold. The simulated deflection at 70°C was 11.9 μm, and experimental deflection was 11-12 μm. We present a study of inbuilt deflection reduction in multimetal movable layers without change in actuation voltage of the switch. The design study was initially carried out on cantilevers and then on structural membrane of STS. STS with proposed multilayer of Cr-Au-Au-Ti-Au has a simulated deflection of 0.56 μm at 70°C. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2212

    Force distribution in closed kinematic chains

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    Experimental and CFD analysis of a gas-lubricated foil thrust bearing for various foil configurations

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    Thrust foil bearings operating at hydrodynamic conditions are self-acting (aerodynamic) bearings that support high-speed shafts at mild loading conditions with air as a lubricant and are generally used in low-power gas turbines. This paper presents an experimental study and a detailed computational analysis of dynamic characteristics of the foil thrust bearing (FTB) in terms of load-carrying capabilities as a function of thrust runner speed and gap between the bearing assembly and the runner by considering the effect of bearing parameters such as number of foils, shape of the foils, and assembly of foils on the bearing pad. The parametric study was conducted on a newly conceptualized bearing test rig capable of rotating up to 45,000 rpm speeds that measured the axial loads of the air foil thrust bearings (AFTB). The computational model of the foil thrust bearings for various configurations with top foils is simulated using multiphysics software for foil deflections and pressure distributions on the foil surface. The numerical results were compared with the experimental values, while the air foil thrust bearings with multilayered foils called cascaded foils (patented) had higher load capability in comparison to other conventional bearing models

    Measurement of Ultra-Low Potassium Contaminations with Accelerator Mass Spectrometry

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    Levels of trace radiopurity in active detector materials is a subject of major concern in low-background experiments. Among the radio-isotopes, \k40 is one of the most abundant and yet whose signatures are difficult to reject. Procedures were devised to measure trace potassium concentrations in the inorganic salt CsI as well as in organic liquid scintillator (LS) with Accelerator Mass Spectrometry (AMS), giving, respectively, the \k40-contamination levels of 1010\sim 10^{-10} and 1013\sim 10^{-13} g/g. Measurement flexibilities and sensitivities are improved over conventional methods. The projected limiting sensitivities if no excess of potassium signals had been observed over background are 8×10138 \times 10^{-13} g/g and 3×10173 \times 10^{-17} g/g for the CsI and LS, respectively. Studies of the LS samples indicate that the radioactive contaminations come mainly in the dye solutes, while the base solvents are orders of magnitude cleaner. The work demonstrate the possibilities of measuring naturally-occurring isotopes with the AMS techniques.Comment: 18 pages, 4 figures, 3 table

    Security of quantum cryptography using balanced homodyne detection

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    In this paper we investigate the security of a quantum cryptographic scheme which utilizes balanced homodyne detection and weak coherent pulse (WCP). The performance of the system is mainly characterized by the intensity of the WCP and postselected threshold. Two of the simplest intercept/resend eavesdropping attacks are analyzed. The secure key gain for a given loss is also discussed in terms of the pulse intensity and threshold.Comment: RevTeX4, 8pages, 7 figure

    7-(2-Chloro­phen­yl)-2,6,9-trimethyl­dibenzo[b,h][1,6]naphthyridine

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    In the title compound, C25H19ClN2, the dibenzo[b,h][1,6]naphthyridine system is planar to within 0.16 (2) Å, and the chloro­phenyl ring is inclined to it by 82.53 (7)°. In the crystal, mol­ecules are linked by C—H⋯N hydrogen bonds, forming chains propagating in [100]. There are also a number of weak π–π stacking inter­actions present [centroid–centroid distances = 3.8531 (1) and 3.7631 (1) Å]

    Volume Effects on the Glass Transition Dynamics

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    The role of jamming (steric constraints) and its relationship to the available volume is addressed by examining the effect that certain modifications of a glass-former have on the ratio of its isochoric and isobaric activation enthalpies. This ratio reflects the relative contribution of volume (density) and temperature (thermal energy) to the temperature-dependence of the relaxation times of liquids and polymers. We find that an increase in the available volume confers a stronger volume-dependence to the relaxation dynamics, a result at odds with free volume interpretations of the glass transition.Comment: 9 pages 5 figure
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