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排序方式: 共有240条查询结果,搜索用时 15 毫秒
1.
R.H. Laskar D. Chakrabarty F.A. Talukdar K. Sreenivasa Rao K. Banerjee 《Applied Soft Computing》2012,12(11):3332-3342
In this paper, we present a comparative analysis of artificial neural networks (ANNs) and Gaussian mixture models (GMMs) for design of voice conversion system using line spectral frequencies (LSFs) as feature vectors. Both the ANN and GMM based models are explored to capture nonlinear mapping functions for modifying the vocal tract characteristics of a source speaker according to a desired target speaker. The LSFs are used to represent the vocal tract transfer function of a particular speaker. Mapping of the intonation patterns (pitch contour) is carried out using a codebook based model at segmental level. The energy profile of the signal is modified using a fixed scaling factor defined between the source and target speakers at the segmental level. Two different methods for residual modification such as residual copying and residual selection methods are used to generate the target residual signal. The performance of ANN and GMM based voice conversion (VC) system are conducted using subjective and objective measures. The results indicate that the proposed ANN-based model using LSFs feature set may be used as an alternative to state-of-the-art GMM-based models used to design a voice conversion system. 相似文献
2.
D. K. Bhattacharyya M. M. Chakrabarty K. Kar 《European Journal of Lipid Science and Technology》1985,87(7):278-282
Acidolysis reaction of sal fat (Shorea robusta) with palmitic acid has been studied in relation to the operating variables like catalyst system and concentration, reaction temperature and time and molar ratios of reactants with the object of introducing more palmitic acid which is low in sal fat. The results demonstrate that as low as 2.5% and as high as 39% palmitic acid can be introduced in sal fat at the expense of other acids under the influence of various operating conditions. The products obtained differ from original sal fat in respect of chemical composition and slip point. The importance of such study is that there are possibilities of getting plastic fats of diverse properties for edible and industrial uses. 相似文献
3.
Rajan K. Chakrabarty Mark A. Garro Shammah Chancellor Hans Moosmüller 《Computer Physics Communications》2009,180(8):1376-1381
Computer simulation techniques have found extensive use in establishing empirical relationships between three-dimensional (3d) and two-dimensional (2d) projected properties of particles produced by the process of growth through the agglomeration of smaller particles (monomers). In this paper, we describe a package, FracMAP, that has been written to simulate 3d quasi-fractal agglomerates and create their 2d pixelated projection images by restricting them to stable orientations as commonly encountered for quasi-fractal agglomerates collected on filter media for electron microscopy. Resulting 2d images are analyzed for their projected morphological properties.
Program summary
Program title: FracMAPCatalogue identifier: AEDD_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEDD_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 4722No. of bytes in distributed program, including test data, etc.: 27 229Distribution format: tar.gzProgramming language: C++Computer: PCOperating system: Windows, LinuxRAM: 2.0 MegabytesClassification: 7.7Nature of problem: Solving for a suitable fractal agglomerate construction under constraints of typical morphological parameters.Solution method: Monte Carlo approximation.Restrictions: Problem complexity is not representative of run-time, since Monte Carlo iterations are of a constant complexity.Additional comments: The distribution file contains two versions of the FracMAP code, one for Windows and one for Linux.Running time: 1 hour for a fractal agglomerate of size 25 on a single processor. 相似文献4.
In the recent years, we have seen that Grover search algorithm (Proceedings, 28th annual ACM symposium on the theory of computing, pp. 212–219, 1996) by using quantum parallelism has revolutionized the field of solving huge class of NP problems in comparisons to classical systems. In this work, we explore the idea of extending Grover search algorithm to approximate algorithms. Here we try to analyze the applicability of Grover search to process an unstructured database with a dynamic selection function in contrast to the static selection function used in the original work (Grover in Proceedings, 28th annual ACM symposium on the theory of computing, pp. 212–219, 1996). We show that this alteration facilitates us to extend the application of Grover search to the field of randomized search algorithms. Further, we use the dynamic Grover search algorithm to define the goals for a recommendation system based on which we propose a recommendation algorithm which uses binomial similarity distribution space giving us a quadratic speedup over traditional classical unstructured recommendation systems. Finally, we see how dynamic Grover search can be used to tackle a wide range of optimization problems where we improve complexity over existing optimization algorithms. 相似文献
5.
The electrical conductivity and Seebeck coefficients have been measured from room temperature to 500° C for polycrystalline V2O5 and V2O5 doped with lithium and sodium in the -phase range. The conductivity increases with doping and the energy of activation decreases. The Seebeck coefficient indicates that electrons are the majority carriers. The results have been discussed in terms of the two-level hopping model. 相似文献
6.
The main focus of this paper is a pair of new approximation algorithms for certain integer programs. First, for covering integer
programs {min cx:Ax≥b,0≤x≤d} where A has at most k nonzeroes per row, we give a k-approximation algorithm. (We assume A,b,c,d are nonnegative.) For any k≥2 and ε>0, if P≠NP this ratio cannot be improved to k−1−ε, and under the unique games conjecture this ratio cannot be improved to k−ε. One key idea is to replace individual constraints by others that have better rounding properties but the same nonnegative
integral solutions; another critical ingredient is knapsack-cover inequalities. Second, for packing integer programs {max cx:Ax≤b,0≤x≤d} where A has at most k nonzeroes per column, we give a (2k
2+2)-approximation algorithm. Our approach builds on the iterated LP relaxation framework. In addition, we obtain improved
approximations for the second problem when k=2, and for both problems when every A
ij
is small compared to b
i
. Finally, we demonstrate a 17/16-inapproximability for covering integer programs with at most two nonzeroes per column. 相似文献
7.
S. K. Shekhawat V. Basavaraj V. D. Hiwarkar R. Chakrabarty J. Nemade P. J. Guruprasad K. G. Suresh R. D. Doherty I. Samajdar 《Metallurgical and Materials Transactions A》2014,45(9):3695-3698
Non-grain oriented electrical steel, with minor in-grain orientation gradients, was subjected to interrupted tensile deformations and concurrent microtexture, magnetic property and residual stress measurements. After the upper yield point, clear signatures of mechanical stress relief were observed. Changes in orientation gradients led to annihilation of low-angle (1 to 3 deg) boundaries. Prior deformation compressive residual stresses became tensile and magnetic properties improved. Beyond an optimum true strain of 0.01, this boundary annihilation ceased, compressive stresses were generated, and magnetic properties degraded. 相似文献
8.
Giulia Cisbani Alex Koppel Adam H. Metherel Mackenzie E. Smith Kankana N. Aji Ana C. Andreazza Romina Mizrahi Richard P. Bazinet 《Lipids》2022,57(2):125-140
Cannabis is now legal in many countries and while numerous studies have reported on its impact on cognition and appetite regulation, none have examined fatty acid metabolism in young cannabis users. We conducted an exploratory analysis to evaluate cannabis impact on fatty acid metabolism in cannabis users (n = 21) and non-cannabis users (n = 16). Serum levels of some saturated and monounsaturated fatty acids, including palmitic, palmitoleic, and oleic acids were higher in cannabis users compared to nonusers. As palmitic acid can be derived from diet or lipogenesis from sugars, we evaluated lipogenesis using a de novo lipogenesis index (palmitate/linoleic acid) and carbon-specific isotope analysis, which allows for the determination of fatty acid 13C signature. The significantly higher de novo lipogenesis index in the cannabis users group along with a more enriched 13C signature of palmitic acid suggested an increase in lipogenesis. In addition, while serum glucose concentration did not differ between groups, pyruvate and lactate were lower in the cannabis user group, with pyruvate negatively correlating with palmitic acid. Furthermore, the endocannabinoid 2-arachidonoylglycerol was elevated in cannabis users and could contribute to lipogenesis by activating the cannabinoid receptor 1. Because palmitic acid has been suggested to increase inflammation, we measured peripheral cytokines and observed no changes in inflammatory cytokines. Finally, an anti-inflammatory metabolite of palmitic acid, palmitoylethanolamide was elevated in cannabis users. Our results suggest that lipogenic activity is increased in cannabis users; however, future studies, including prospective studies that control dietary intake are required. 相似文献
9.
Payton Beeler Nicholas O. Jensen Soyoung Kim Amy Robichaux-Viehoever Bradley L. Schlaggar Deanna J. Greene Kevin J. Black Rajan K. Chakrabarty 《Journal of the Royal Society Interface》2022,19(187)
Tics manifest as brief, purposeless and unintentional movements or noises that, for many individuals, can be suppressed temporarily with effort. Previous work has hypothesized that the chaotic temporal nature of tics could possess an inherent fractality, that is, have neighbour-to-neighbour correlation at all levels of timescale. However, demonstrating this phenomenon has eluded researchers for more than two decades, primarily because of the challenges associated with estimating the scale-invariant, power law exponent—called the fractal dimension Df—from fractional Brownian noise. Here, we confirm this hypothesis and establish the fractality of tics by examining two tic time series datasets collected 6–12 months apart in children with tics, using random walk models and directional statistics. We find that Df is correlated with tic severity as measured by the YGTTS total tic score, and that Df is a sensitive parameter in examining the effect of several tic suppression conditions on the tic time series. Our findings pave the way for using the fractal nature of tics as a robust quantitative tool for estimating tic severity and treatment effectiveness, as well as a possible marker for differentiating typical from functional tics. 相似文献
10.
Optimal Dynamic Monitoring Network Design and Identification of Unknown Groundwater Pollution Sources 总被引:2,自引:2,他引:0
The identification of unknown pollution sources is a prerequisite for designing of a remediation strategy. In most of the
real world situations, it is difficult to identify the pollution sources without a scientifically designed efficient monitoring
network. The locations of the contaminant concentration measurement sites would determine the efficiency of the unknown source
identification process to a large extent. Therefore coupled and iterative sequential source identification and dynamic monitoring
network design framework is developed. The coupled approach provides a framework for necessary sequential exchange of information
between monitoring network and source identification methodology. The preliminary identification of unknown sources, based
on limited concentration data from existing arbitrarily located wells provides the initial rough estimate of the source fluxes.
These identified source fluxes are then utilized for designing an optimal monitoring network for the first stage. Both the
monitoring network and source identification process is repeated by sequential identification of sources and design of monitoring
network which provides the feedback information. In the optimal source identification model, the Jacobian matrix which is
the determinant for the search direction in the nonlinear optimization model links the groundwater flow-transport simulator
and the optimization method. For the optimal monitoring network design, the integer programming based optimal design model
requires as input, simulated sets of concentration data. In the proposed methodology, the concentration measurement data from
the designed and implemented monitoring network are used as feedback information for sequential identification of unknown
pollution sources. The potential applicability of the developed methodology is demonstrated for an illustrative study area. 相似文献