3,116,746 research outputs found

    Buffering Capacity of Paddy Field as the Reservoir of Rainwater and Surface Runoff in the Lowokwaru Subdistrict, Malang, East Java

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    Paddy fields produce ecological services that improve environmental quality in urban areas, one of them was flood control through retaining rainwater and surface runoff within the embankment of paddy field. The ability to retain water is known as the buffering capacity (BC), which is the function of soil moisture, embankment height, water inundation and rice-plant interception during the growing periode. The intermitten system of water inundation applied by farmers resulted in changes of the BC on daily basis. The calculation of BC was divided into five categories for accuracy, which were : (1) BC during the Harvest; (2) BC with inundation at vegetative and generative phase (VGG); (3) BC with inundation during Land Preparation and Planting phase (OTTG); (4) BC without inundation during the vegetative and generative phase (VGTG); and (5) BC without inundation during the land preparation and planting phase (OTTTG). The purpose of this research was to measure potential buffering capacity of paddy field in Lowokwaru Subdistrictand to estimate amount of rainwater and surface runoff which could be accommodated within the buffering capacity. The average of daily BC in seven different villages were 1,650.81– 3,961.81 m3/ha and the total BC for 241 paddy field was about 823,156.36 m3.It was only a small percentage of average daily BC filled by rainwater (14.07-33.31%) and left the rest to be filled by surface runoff water. The paddy field of 241 ha in Lowokwaru Subdistrictis was capable to receive surface runoff from surrounding areas up to 1,698.66 ha

    On the Capacity of Multiplicative Finite-Field Matrix Channels

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    This paper deals with the multiplicative finite-field matrix channel, a discrete memoryless channel whose input and output are matrices (over a finite field) related by a multiplicative transfer matrix. The model considered here assumes that all transfer matrices with the same rank are equiprobable, so that the channel is completely characterized by the rank distribution of the transfer matrix. This model is seen to be more flexible than previously proposed ones in describing random linear network coding systems subject to link erasures, while still being sufficiently simple to allow tractability. The model is also conservative in the sense that its capacity provides a lower bound on the capacity of any channel with the same rank distribution. A main contribution is to express the channel capacity as the solution of a convex optimization problem which can be easily solved by numerical computation. For the special case of constant-rank input, a closed-form expression for the capacity is obtained. The behavior of the channel for asymptotically large field size or packet length is studied, and it is shown that constant-rank input suffices in this case. Finally, it is proved that the well-known approach of treating inputs and outputs as subspaces is information-lossless even in this more general model.Comment: 11 pages, 4 figures, to appear in the IEEE Transactions on Information Theor

    Fine frequency shift of sigle vortex entrance and exit in superconducting loops

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    The heat capacity CpC_{p} of an array of independent aluminum rings has been measured under an external magnetic field H\vec{H} using highly sensitive ac-calorimetry based on a silicon membrane sensor. Each superconducting vortex entrance induces a phase transition and a heat capacity jump and hence CpC_{p} oscillates with H\vec{H}. This oscillatory and non-stationary behaviour measured versus the magnetic field has been studied using the Wigner-Ville distribution (a time-frequency representation). It is found that the periodicity of the heat capacity oscillations varies significantly with the magnetic field; the evolution of the period also depends on the sweeping direction of the field. This can be attributed to a different behavior between expulsion and penetration of vortices into the rings. A variation of more than 15% of the periodicity of the heat capacity jumps is observed as the magnetic field is varied. A description of this phenomenon is given using an analytical solution of the Ginzburg-Landau equations of superconductivity

    On Network Coding Capacity - Matroidal Networks and Network Capacity Regions

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    One fundamental problem in the field of network coding is to determine the network coding capacity of networks under various network coding schemes. In this thesis, we address the problem with two approaches: matroidal networks and capacity regions. In our matroidal approach, we prove the converse of the theorem which states that, if a network is scalar-linearly solvable then it is a matroidal network associated with a representable matroid over a finite field. As a consequence, we obtain a correspondence between scalar-linearly solvable networks and representable matroids over finite fields in the framework of matroidal networks. We prove a theorem about the scalar-linear solvability of networks and field characteristics. We provide a method for generating scalar-linearly solvable networks that are potentially different from the networks that we already know are scalar-linearly solvable. In our capacity region approach, we define a multi-dimensional object, called the network capacity region, associated with networks that is analogous to the rate regions in information theory. For the network routing capacity region, we show that the region is a computable rational polytope and provide exact algorithms and approximation heuristics for computing the region. For the network linear coding capacity region, we construct a computable rational polytope, with respect to a given finite field, that inner bounds the linear coding capacity region and provide exact algorithms and approximation heuristics for computing the polytope. The exact algorithms and approximation heuristics we present are not polynomial time schemes and may depend on the output size.Comment: Master of Engineering Thesis, MIT, September 2010, 70 pages, 10 figure

    Prediction of vertical bearing capacity of waveform micropile

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    This study proposes a predictive equation for bearing capacity considering the behaviour characteristics of a waveform micropile that can enhance the bearing capacity of a conventional micropile. The bearing capacity of the waveform micropile was analysed by a three-dimensional numerical model with soil and pile conditions obtained from the field and centrifuge tests. The load-transfer mechanism of the waveform micropile was revealed by the numerical analyses, and a new predictive equation for the bearing capacity was proposed. The bearing capacities of the waveform micropile calculated by the new equation were comparable with those measured from the field and centrifuge tests. This validated a prediction potential of the new equation for bearing capacity of waveform micropiles

    Classical capacity of the lossy bosonic channel: the exact solution

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    The classical capacity of the lossy bosonic channel is calculated exactly. It is shown that its Holevo information is not superadditive, and that a coherent-state encoding achieves capacity. The capacity of far-field, free-space optical communications is given as an example.Comment: 4 pages, 2 figures (revised version
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