3,160 research outputs found
Design of 1 :7 .645 scale LCA high speed air intake model
This report details the mechanical design aspects of the
1:7.645 scale LCA high speed air intake model. The model is
intended to generate intake data in the transonic range 0.7 & 1.3 by Aeronautical Development Agency. The model has been designed for testing in the S2MA ONERA wind tunnel facilities. The 1:7.645 scale model is basically a composite model with metallic bulkheads/inserts and mainly
consists of front fuselage, the wing, the canopy, interchangeable front duct modules, the rear portion of the CFRP duct, the main bulkhead, the heat exchanger duct, the sting, kulite rake, rear portion of the metallic duct including venturi, butterfly valve and diffuser. The kulite rake, the sting and the rear portion of the duct available with ONERA is made use of in the present model design. The steel bulkhead provides anchor support for the model
in the tunnel through a flange mounted sting. The model has been designed to meet all the requirements of ONERA regarding model design and construction. For the design of the present model, the critical loads are scaled down from the load data of the 1:4.405 scale model. Structural analysis based on strength of materials approach has been carried out on the components of the model viz. forward fuselage, main bulkhead, air intake duct, and the splitter plate. FEN analysis has been carried out on the wing
which is supposed to be the critical element of the model. The stress analysis shows that adequate margins of safety are available for all the components of the model
Using simulation studies to evaluate statistical methods
Simulation studies are computer experiments that involve creating data by
pseudorandom sampling. The key strength of simulation studies is the ability to
understand the behaviour of statistical methods because some 'truth' (usually
some parameter/s of interest) is known from the process of generating the data.
This allows us to consider properties of methods, such as bias. While widely
used, simulation studies are often poorly designed, analysed and reported. This
tutorial outlines the rationale for using simulation studies and offers
guidance for design, execution, analysis, reporting and presentation. In
particular, this tutorial provides: a structured approach for planning and
reporting simulation studies, which involves defining aims, data-generating
mechanisms, estimands, methods and performance measures ('ADEMP'); coherent
terminology for simulation studies; guidance on coding simulation studies; a
critical discussion of key performance measures and their estimation; guidance
on structuring tabular and graphical presentation of results; and new graphical
presentations. With a view to describing recent practice, we review 100
articles taken from Volume 34 of Statistics in Medicine that included at least
one simulation study and identify areas for improvement.Comment: 31 pages, 9 figures (2 in appendix), 8 tables (1 in appendix
A model-based multithreshold method for subgroup identification
Thresholding variable plays a crucial role in subgroup identification for personalizedmedicine. Most existing partitioning methods split the sample basedon one predictor variable. In this paper, we consider setting the splitting rulefrom a combination of multivariate predictors, such as the latent factors, principlecomponents, and weighted sum of predictors. Such a subgrouping methodmay lead to more meaningful partitioning of the population than using a singlevariable. In addition, our method is based on a change point regression modeland thus yields straight forward model-based prediction results. After choosinga particular thresholding variable form, we apply a two-stage multiple changepoint detection method to determine the subgroups and estimate the regressionparameters. We show that our approach can produce two or more subgroupsfrom the multiple change points and identify the true grouping with high probability.In addition, our estimation results enjoy oracle properties. We design asimulation study to compare performances of our proposed and existing methodsand apply them to analyze data sets from a Scleroderma trial and a breastcancer study
P04-19. Analysis of the binding of multiple clades of HIV-1 by a modified virus capture assay
PHARMACOGNOSTICAL, PHYSICOCHEMICAL AND HPTLC EVALUATION OF TRIVRITTADI KWATHA: A POLYHERBAL FORMULATION
Background: Trivrittadi kwatha is mentioned in Charaka samhita as a therapeutic formulation to treat Kushtha (Skin disorder). The skin diseases are considered in the umbrella of Kushtha. There is no definite line of treatment is given in the classics but the Seers have described Shwitra (Vitiligo) under the kushtha and line of treatment should be done like Kushtha. Vitiligo affects 1% of the population worldwide but management is till unsatisfactory. Trivrittadi kwatha contains Trivritta (Operaculina turpethum (Linn.), Danti (Boliospermum montanum Muell-Arg.) and Triphala which is compound of Haritaki (Terminalia chebula), Bibhitaki (Terminalia belerica) and Amalaki (Emblica officinalis). This polyherbal formulation has enough potential to do Virechana (therapeutic purgation). Method: Trivrittadi kwatha powder was evaluated for their pharmacognostical and pharmaceutical analysis. Results: Microscopic characters were found of Trivritta, Danti, Haritaki, Bibhitaki and Amalaki. Results obtained in pharmaceutical parameters of Trivrittadi kwatha powder like loss on drying 8.2 % w/w, Ash value 6.268 %, Alcohol soluble extract 91.5 % w/w etc. are within limit mentioned by Ayurvedic Pharmacopoeia of India. High Performance Thin Layer Chromatography (HPTLC) profile of Trivrittadi kwatha powder showed similarities in number of spots. Conclusion: From the study, data developed can be espoused for laying down the standards for Trivrittadi kwatha
Congruent families and invariant tensors
Classical results of Chentsov and Campbell state that -- up to constant
multiples -- the only -tensor field of a statistical model which is
invariant under congruent Markov morphisms is the Fisher metric and the only
invariant -tensor field is the Amari-Chentsov tensor. We generalize this
result for arbitrary degree , showing that any family of -tensors which
is invariant under congruent Markov morphisms is algebraically generated by the
canonical tensor fields defined in an earlier paper
On the moment limit of quantum observables, with an application to the balanced homodyne detection
We consider the moment operators of the observable (i.e. a semispectral
measure or POM) associated with the balanced homodyne detection statistics,
with paying attention to the correct domains of these unbounded operators. We
show that the high amplitude limit, when performed on the moment operators,
actually determines uniquely the entire statistics of a rotated quadrature
amplitude of the signal field, thereby verifying the usual assumption that the
homodyne detection achieves a measurement of that observable. We also consider,
in a general setting, the possibility of constructing a measurement of a single
quantum observable from a sequence of observables by taking the limit on the
level of moment operators of these observables. In this context, we show that
under some natural conditions (each of which is satisfied by the homodyne
detector example), the existence of the moment limits ensures that the
underlying probability measures converge weakly to the probability measure of
the limiting observable. The moment approach naturally requires that the
observables be determined by their moment operator sequences (which does not
automatically happen), and it turns out, in particular, that this is the case
for the balanced homodyne detector.Comment: 22 pages, no figure
The timing of death in patients with tuberculosis who die during anti-tuberculosis treatment in Andhra Pradesh, South India
Background: India has 2.0 million estimated tuberculosis (TB) cases per annum with an estimated 280,000 TBrelated
deaths per year. Understanding when in the course of TB treatment patients die is important for
determining the type of intervention to be offered and crucially when this intervention should be given. The
objectives of the current study were to determine in a large cohort of TB patients in India:- i) treatment outcomes
including the number who died while on treatment, ii) the month of death and iii) characteristics associated with
“early” death, occurring in the initial 8 weeks of treatment.
Methods: This was a retrospective study in 16 selected Designated Microscopy Centres (DMCs) in Hyderabad,
Krishna and Adilabad districts of Andhra Pradesh, South India. A review was performed of treatment cards and
medical records of all TB patients (adults and children) registered and placed on standardized anti-tuberculosis
treatment from January 2005 to September 2009.
Results: There were 8,240 TB patients (5183 males) of whom 492 (6%) were known to have died during treatment.
Case-fatality was higher in those previously treated (12%) and lower in those with extra-pulmonary TB (2%). There
was an even distribution of deaths during anti-tuberculosis treatment, with 28% of all patients dying in the first 8
weeks of treatment. Increasing age and new as compared to recurrent TB disease were significantly associated
with “early death”.
Conclusion: In this large cohort of TB patients, deaths occurred with an even frequency throughout anti-TB
treatment. Reasons may relate to i) the treatment of the disease itself, raising concerns about drug adherence,
quality of anti-tuberculosis drugs or the presence of undetected drug resistance and ii) co-morbidities, such as HIV/
AIDS and diabetes mellitus, which are known to influence mortality. More research in this area from prospective
and retrospective studies is needed
Fast and Accurate Camera Covariance Computation for Large 3D Reconstruction
Estimating uncertainty of camera parameters computed in Structure from Motion
(SfM) is an important tool for evaluating the quality of the reconstruction and
guiding the reconstruction process. Yet, the quality of the estimated
parameters of large reconstructions has been rarely evaluated due to the
computational challenges. We present a new algorithm which employs the sparsity
of the uncertainty propagation and speeds the computation up about ten times
\wrt previous approaches. Our computation is accurate and does not use any
approximations. We can compute uncertainties of thousands of cameras in tens of
seconds on a standard PC. We also demonstrate that our approach can be
effectively used for reconstructions of any size by applying it to smaller
sub-reconstructions.Comment: ECCV 201
Characterizations of k-commutative equalities for some outer generalized inverses
[EN] In this paper, we present necessary and sufficient conditions for the k-commutative equality , where X is an outer generalized inverse of the square matrix A. Also, we give new representations for core EP, DMP, and CMP inverses of square matrices as outer inverses with prescribed null space and range. In addition, we characterize the core EP inverse as the solution of a new system of matrix equations.D. E. Ferreyra F. E. Levis Partially supported by a Consejo Nacional de Investigaciones Científicas y Técnicas CONICET s Posdoctoral Research Fellowship, UNRC [grant number PPI 18/C472] and CONICET
[grant number PIP 112-201501-00433CO], respectively. N. Thome Partially supported by Secretaría de Estado de Investigación, Desarrollo e Innovación Ministerio de Economía, Industria y Competitividad of Spain [grant number DGI MTM2013-43678-P and Grant Red de Excelen- cia PMTM2017-90682-REDT]. D. E. Ferreyra and N. Thome Partially supported Universidad Nacional de La Pampa (UNLPam), Facultad de Ingeniería [grant Resol. No 155/14].Ferreyra, DE.; Levis, F.; Thome, N. (2018). Characterizations of k-commutative equalities for some outer generalized inverses. Linear and Multilinear Algebra. 1-16. https://doi.org/10.1080/03081087.2018.1500994S116Baksalary, O. M., & Trenkler, G. (2010). Core inverse of matrices. Linear and Multilinear Algebra, 58(6), 681-697. doi:10.1080/03081080902778222Manjunatha Prasad, K., & Mohana, K. S. (2013). Core–EP inverse. Linear and Multilinear Algebra, 62(6), 792-802. doi:10.1080/03081087.2013.791690Malik, S. B., & Thome, N. (2014). On a new generalized inverse for matrices of an arbitrary index. Applied Mathematics and Computation, 226, 575-580. doi:10.1016/j.amc.2013.10.060Mehdipour, M., & Salemi, A. (2017). On a new generalized inverse of matrices. Linear and Multilinear Algebra, 66(5), 1046-1053. doi:10.1080/03081087.2017.1336200Malik, S. B., Rueda, L., & Thome, N. (2016). The class ofm-EPandm-normal matrices. Linear and Multilinear Algebra, 64(11), 2119-2132. doi:10.1080/03081087.2016.1139037Wang, H. (2016). Core-EP decomposition and its applications. Linear Algebra and its Applications, 508, 289-300. doi:10.1016/j.laa.2016.08.008Wang H, Chen J. Weak group inverse. Available from: http://arxiv.org/abs/1704.08403v1Wei, Y. (1998). A characterization and representation of the generalized inverse A(2)T,S and its applications. Linear Algebra and its Applications, 280(2-3), 87-96. doi:10.1016/s0024-3795(98)00008-1Rakić, D. S., Dinčić, N. Č., & Djordjević, D. S. (2014). Core inverse and core partial order of Hilbert space operators. Applied Mathematics and Computation, 244, 283-302. doi:10.1016/j.amc.2014.06.112Stanimirović, P. S., Katsikis, V. N., & Ma, H. (2016). Representations and properties of theW-Weighted Drazin inverse. Linear and Multilinear Algebra, 65(6), 1080-1096. doi:10.1080/03081087.2016.1228810Ferreyra, D. E., Levis, F. E., & Thome, N. (2017). Revisiting the core EP inverse and its extension to rectangular matrices. Quaestiones Mathematicae, 41(2), 265-281. doi:10.2989/16073606.2017.1377779Deng, C. Y., & Du, H. K. (2009). REPRESENTATIONS OF THE MOORE-PENROSE INVERSE OF 2×2 BLOCK OPERATOR VALUED MATRICES. Journal of the Korean Mathematical Society, 46(6), 1139-1150. doi:10.4134/jkms.2009.46.6.1139Wang, H., & Liu, X. (2014). Characterizations of the core inverse and the core partial ordering. Linear and Multilinear Algebra, 63(9), 1829-1836. doi:10.1080/03081087.2014.97570
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