1,912 research outputs found

    Performance of wind turbines in a turbulent atmosphere

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    The effect of atmospheric turbulence on the power fluctuations of large wind turbines was studied. The significance of spatial non-uniformities of the wind is emphasized. The turbulent wind with correlation in time and space is simulated on the computer by Shinozukas method. The wind turbulence is modelled according to the Davenport spectrum with an exponential spatial correlation function. The rotor aerodynamics is modelled by simple blade element theory. Comparison of the spectrum of power output signal between 1-D and 3-D turbulence, shows the significant power fluctuations centered around the blade passage frequency

    Installation of fishing net tracking buoys in deep sea multiday tuna drift gillnetters at Chennai

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    The deep sea multiday tuna drift gillnetters face many risks while they engage in fishing. The cutting and stealing of nets by fishermen of other boats or damage of the nets by the ships is common. As the total length of a net when set is around 5 to 6 nautical miles (nmi) and the fishing is carried out during night, quite often the fishermen come to know about the loss only at the time of hauling the net. Another serious issue is the possibility of collision with an approaching ship as sometimes the fishing ground can be on the same track of a ship and fishermen notice it only when the ship is too near to them. Installation of fishing net tracking buoy can effectively avoid these risks and enable a hassle free fishing trip

    The Schwinger SU(3) construction - I: Multiplicity problem and relation to induced representations

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    The Schwinger oscillator operator representation of SU(3) is analysed with particular reference to the problem of multiplicity of irreducible representations. It is shown that with the use of an Sp(2,R)Sp(2,R) unitary representation commuting with the SU(3) representation, the infinity of occurrences of each SU(3) irreducible representation can be handled in complete detail. A natural `generating representation' for SU(3), containing each irreducible representation exactly once, is identified within a subspace of the Schwinger construction; and this is shown to be equivalent to an induced representation of SU(3).Comment: Latex, 25 page

    Multi-objective Optimisation of Multi-robot Task Allocation with Precedence Constraints

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    Efficacy of the multi-robot systems depends on proper sequencing and optimal allocation of robots to the tasks. Focuses on deciding the optimal allocation of set-of-robots to a set-of-tasks with precedence constraints considering multiple objectives. Taguchi’s design of experiments based parameter tuned genetic algorithm (GA) is developed for generalised task allocation of single-task robots to multi-robot tasks. The developed methodology is tested for 16 scenarios by varying the number of robots and number of tasks. The scenarios were tested in a simulated environment with a maximum of 20 robots and 40 multi-robot foraging tasks. The tradeoff between performance measures for the allocations obtained through GA for different task levels was used to decide the optimal number of robots. It is evident that the tradeoffs occur at 20 per cent of performance measures and the optimal number of robot varies between 10 and 15 for almost all the task levels. This method shows good convergence and found that the precedence constraints affect the optimal number of robots required for a particular task level

    Metamaterials for light rays: ray optics without wave-optical analog in the ray-optics limit

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    Volumes of sub-wavelength electromagnetic elements can act like homogeneous materials: metamaterials. In analogy, sheets of optical elements such as prisms can act ray-optically like homogeneous sheet materials. In this sense, such sheets can be considered to be metamaterials for light rays (METATOYs). METATOYs realize new and unusual transformations of the directions of transmitted light rays. We study here, in the ray-optics and scalar-wave limits, the wave-optical analog of such transformations, and we show that such an analog does not always exist. Perhaps, this is the reason why many of the ray-optical possibilities offered by METATOYs have never before been considered.Comment: 10 pages, 3 figures, references update

    (R1960) Connectedness and Compactness in Fuzzy Nano Topological Spaces via Fuzzy Nano Z Open Sets

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    In this paper, we study the notion of fuzzy nano Z connected spaces, fuzzy nano Z disconnected spaces, fuzzy nano Z compact spaces and fuzzy nano Z separated sets in fuzzy nano topological spaces. We also give some properties and theorems of such concepts with connectedness and compactness in fuzzy nano topological spaces

    Cloud Based Vehicle Parking System for Anonymous Place Using Internet of Things

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    The intention of our project is to create a smart parking system for smart cities and malls to find a parking space that is well suited to their respective aspects. That is, it can help in finding either the nearest spot or the best one. Thus the algorithm increases the efficiency of the cloud based system and hence develops a network architecture based on internet of things. We have also successfully implemented the proposed system in the real world
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