163 research outputs found
Sense resolution properties of logical imaging
The evaluation of an implication by Imaging is a logical technique developed
in the framework of modal logic. Its interpretation in the context of a âpossible
worldsâ semantics is very appealing for IR. In 1994, Crestani and Van Rijsbergen
proposed an interpretation of Imaging in the context of IR based on the assumption
that âa term is a possibleworldâ. This approach enables the exploitation of termâ
term relationshipswhich are estimated using an information theoretic measure.
Recent analysis of the probability kinematics of Logical Imaging in IR have
suggested that this technique has some interesting sense resolution properties. In
this paper we will present this new line of research and we will relate it to more
classical research into word senses
The troubles with using a logical model of IR on a large collection of documents
This is a paper of two halves. First, a description of a logical model of IR known as imaging will be presented. Unfortunately due to constraints of time and computing resource this model was not implemented in time for this round of TREC. Therefore this paper's second half describes the more conventional IR model and system used to generate the Glasgow IR result set (glair1)
The troubles with using a logical model of IR on a large collection of documents
This is a paper of two halves. First, a description of a logical model of IR known as imaging will be presented.
Unfortunately due to constraints of time and computing resource this model was not implemented in time for this round
of TREC. Therefore this paperâs second half describes the more conventional IR model and system used to generate
the Glasgow IR result set (glair1)
NRT - news retrieval tool
The amounts of information that mankind produces are vast, running into billions of
documents. Traditional ways of holding this information have become impractical and so
methods of storage are being switched from paper and microfiche to magnetic and optical
discs. In the last thirty years as more information has been put onto computers, work has gone
into using the computer to get away from the restrictiveness of manual indexing and move
towards a more flexible system of information acquisition.
Many companies exist offering (for a price) the opportunity to access the information stored on
their systems. Unfortunately, most of these companies use software that was developed in the
sixties when the field of information retrieval (IR) was still very young. This means that the
services they offer are rather primitive. The Financial Timesâ IR service, Profile is typical of
such commercial systems. It has been the aim of the NRT project to investigate ways of
incorporating the new ideas in IR, that have occurred in the last ten to fifteen years, into Profile
A methodology to allow avalanche forecasting on an information retrieval system
This paper presents adaptations and tests undertaken to allow an information retrieval (IR) system to forecast the likelihood of avalanches on a particular day. The forecasting process uses historical data of the weather and avalanche conditions for a large number of days. A method for adapting these data into a form usable by a text-based IR system is first described, followed by tests showing the resulting systemâs accuracy to be equal to existing âcustom builtâ forecasting systems. From this, it is concluded that the adaptation methodology is effective at allowing such data to be used in a text-based IR system. A number of advantages in using an IR system for avalanche forecasting are also presented
Banking regulations : an examination of the failure of African Bank using Mertonâs structural model
The business of banking involves the taking of deposits and the making of loans. Banking balance sheets are
typically highly leveraged, with equity capital generally dwarfed by debt capital. Banks are regulated entities; the
nature of regulation does not, generally, consider the market prices of the securities issued by a particular bank. In
this contribution, we evaluate the capacity of the Merton structural model to provide insight into a bankâs financial
health in the context of the failure of African Bank in 2014.http://www.sajs.co.zaam2017Mathematics and Applied Mathematic
Lack of cardiac differentiation in c-kit-enriched porcine bone marrow and spleen hematopoietic cell cultures using 5-azacytidine
The adult spleen is a source of early hematopoietic stem cells (HSC). We therefore studied whether culturing spleen or bone marrow (BM) HSC in medium containing 5-azacytidine could induce a cardiac phenotype. c-kit enrichment and depletion of adult pig spleen and BM mononuclear cells were obtained by magnetic bead separation using biotinylated pig stem cell factor (c-kit ligand). Cells were incubated with 5-azacytidine for 24 h and refreshed with 5-azacytidine-free medium every 48 h. Western blot was used to detect cardiac troponin and myosin heavy chains. Alth
Discrete cilia modelling with singularity distributions
We discuss in detail techniques for modelling flows due to finite and infinite arrays of beating cilia. An efficient technique, based on concepts from previous âsingularity modelsâ is described, that is accurate in both near and far-fields. Cilia are modelled as curved slender ellipsoidal bodies by distributing Stokeslet and potential source dipole singularities along their centrelines, leading to an integral equation that can be solved using a simple and efficient discretisation. The computed velocity on the cilium surface is found to compare favourably with the boundary condition. We then present results for two topics of current interest in biology. 1) We present the first theoretical results showing the mechanism by which rotating embryonic nodal cilia produce a leftward flow by a âposterior tilt,â and track particle motion in an array of three simulated nodal cilia. We find that, contrary to recent suggestions, there is no continuous layer of negative fluid transport close to the ciliated boundary. The mean leftward particle transport is found to be just over 1 ÎŒm/s, within experimentally measured ranges. We also discuss the accuracy of models that represent the action of cilia by steady rotlet arrays, in particular, confirming the importance of image systems in the boundary in establishing the far-field fluid transport. Future modelling may lead to understanding of the mechanisms by which morphogen gradients or mechanosensing cilia convert a directional flow to asymmetric gene expression. 2) We develop a more complex and detailed model of flow patterns in the periciliary layer of the airway surface liquid. Our results confirm that shear flow of the mucous layer drives a significant volume of periciliary liquid in the direction of mucus transport even during the recovery stroke of the cilia. Finally, we discuss the advantages and disadvantages of the singularity technique and outline future theoretical and experimental developments required to apply this technique to various other biological problems, particularly in the reproductive system
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