1,733 research outputs found
Efficient Document Indexing Using Pivot Tree
We present a novel method for efficiently searching top-k neighbors for
documents represented in high dimensional space of terms based on the cosine
similarity. Mostly, documents are stored as bag-of-words tf-idf representation.
One of the most used ways of computing similarity between a pair of documents
is cosine similarity between the vector representations, but cosine similarity
is not a metric distance measure as it doesn't follow triangle inequality,
therefore most metric searching methods can not be applied directly. We propose
an efficient method for indexing documents using a pivot tree that leads to
efficient retrieval. We also study the relation between precision and
efficiency for the proposed method and compare it with a state of the art in
the area of document searching based on inner product.Comment: 6 Pages, 2 Figure
Economic Analysis of Post-harvest Losses in Marketing of Vegetables in Uttarakhand
The study has examined the nature and extent of post-harvest losses in vegetable supply chain in the Kumaon division of Uttarakhand. Multistage cluster sampling has been used for selection of 80 vegetable growers, 40 farmers from the hilly region and 40 farmers from the bhabhar region. The sample has also included 25 market functionaries. Twelve major vegetables have been selected for the study. The maximum aggregate post-harvest losses have been found in tomato, followed by potato, brinjal, chilly, French bean and pea. The study has suggested that establishment of producer co-operatives to handle various activities relating to production and marketing of vegetables would help in reducing post-harvest losses.Post-harvest losses, Uttarakhand, Vegetable supply chain, Tomato, Potato, Brinjal, Chilly, French bean, Pea, Agricultural and Food Policy, Q13, Q12, Q18,
Von-Neumann Stability and Singularity Resolution in Loop Quantized Schwarzschild Black Hole
Though loop quantization of several spacetimes has exhibited existence of a
bounce via an explicit evolution of states using numerical simulations, the
question about the way central singularity is resolved in the black hole
interior has remained open. The quantum Hamiltonian constraint in loop
quantization turns out to be a finite difference equation whose stability is
important to understand to gain insights on the viability of the underlying
quantization and resulting physical implications. We take first steps towards
addressing these issues for a loop quantization of the Schwarzschild interior
recently given by Corichi and Singh. Von-Neumann stability analysis is
performed using separability of solutions as well as a full two dimensional
quantum difference equation. This results in a stability condition for black
holes which have a very large mass compared to the Planck mass. For black holes
of smaller masses evidence of numerical instability is found. In addition,
stability analysis for macroscopic black holes leads to a constraint on the
choice of the allowed states in numerical evolution. With the caveat of using
kinematical norm, sharply peaked Gaussian states are evolved using the quantum
difference equation and singularity resolution is obtained. A bounce is found
for one of the triad variables, but for the other triad variable singularity
resolution amounts to a non-singular passage through the zero volume. States
are found to be peaked at the classical trajectory for a long time before and
after the singularity resolution, and retain their semi-classical character
across the zero volume. Our main result is that quantum bounce occurs in loop
quantized Schwarzschild interior at least for macroscopic black holes.Comment: 10 pages, 10 figures; Discussion of results expanded. To appear in
CQ
Biodegradation of an Organic Compounds using Fluidized Bed Reactor
Fluidized beds reactors are used for different purposes; they are still used to produce gasoline and other fuels, along with many other chemicals. Many industrially produced polymers are made using FBR technology, such as rubber, vinyl chloride, polyethylene, and styrene’s. Various utilities also use Fluidized bed reactor for coal gasification, nuclear power plants, and water and waste treatment settings. Used in these applications, fluidized bed reactors allow for a cleaner, more efficient process than previous standard reactor technologies. In this paper a theoretical study about fluidized bed reactors arecarried out and also a fluidized bed reactor for three different reaction schemes (oxidation of benzene to form maleic anhydride, oxidation of naphthalene to form phthalic anhydride and oxidation of ethylene to form ethylene oxide) is designed. Costoptimization for multiple fluidized bed reactors with continuous transport of an immobilized enzyme is also studied and calculated
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