Curvature-Matter Coupling Effects on Axial Gravitational Waves

In this paper, we investigate the propagation of axial gravitational waves in the background of the flat FRW universe in $f(R,T)$ theory. The field equations are obtained for unperturbed as well as axially perturbed FRW metric. These field equations are solved simultaneously to obtain the unknown perturbation parameters. We find that the assumed perturbations can affect matter as well as four-velocity. Moreover, ignoring the material perturbations we explicitly obtain an expression for four-velocity. It is concluded that axial gravitational waves in the curvature-matter coupling background can produce cosmological rotation or have memory effect if the wave profile has a discontinuity at the wavefront.Comment: 17 pages, no figure, to appear in EPJ

Models of Collapsing and Expanding Cylindrical Source in f(R,T) Theory

We discuss the collapsing and expanding solutions of anisotropic charged cylinder in the context of $f(R,T)$ theory ($R$ represents the Ricci scalar and $T$ denotes the trace of energy-momentum tensor). For this purpose, we take an auxiliary solution of Einstein-Maxwell field equations and evaluate expansion scalar whose negative values lead to collapse and positive values give expansion. For both cases, the behavior of density, pressure, anisotropic parameter as well as mass is explored and the effects of charge as well as model parameter on these quantities are examined. The energy conditions are found to be satisfied for both solutions.Comment: 29 pages, 22 figures, to appear in AHE

SmallClient for big data: an indexing framework towards fast data retrieval

Numerous applications are continuously generating massive amount of data and it has become critical to extract useful information while maintaining acceptable computing performance. The objective of this work is to design an indexing framework which minimizes indexing overhead and improves query execution and data search performance with optimum aggregation of computing performance. We propose Small-Client, an indexing framework to speed up query execution. SmallClient has three modules: block creation, index creation and query execution. Block creation module supports improving data retrieval performance with minimum data uploading overhead. Index creation module allows maximum indexes on a dataset to increase index hit ratio with minimized indexing overhead. Finally, query execution module offers incoming queries to utilize these indexes. The evaluation shows that Small-Client outperforms Hadoop full scan with more than 90% search performance. Meanwhile, indexing overhead of SmallClient is reduced to approximately 50% and 80% for index size and indexing time respectively

Combining Speech with textual methods for arabic diacritization

Master'sMASTER OF SCIENC

Classroom learning of English L2 requests : input and interactional opportunities in French secondary schools

With today’s strong focus on communicative competence in second language (L2) classrooms, speech acts like suggestions, requests, refusals, and apologies are often investigated in interlanguage pragmatic (ILP) as well as instructional pragmatics. Even though there is strong evidence in ILP research that purports that L2 learners respond well to pragmatic instruction (Taguchi, 2015), the teaching of L2 pragmatics is not always prioritized in textbooks, teaching programmes or teacher education (Barron, 2016; Savvidou & Economidou-Kogetsidis, 2019) with the consequence that pragmatic learning can only occur incidentally. The present study examines opportunities to acquire L2 requests for 308 English as a foreign language (EFL) learners across 7 years of instruction in French secondary schools, investigating textbooks preferred by teachers, classroom interaction (39 hours), and teacher perspectives (semi-structured interviews with 10 teachers). After a pragmatic analysis of 15 EFL textbooks with a focus on requests, the study examines the incidence of metapragmatic input in 39 hours of teaching in 13 classes at 3 levels, and relates interactional patterns with interview data from the 10 teachers concerned. Findings suggest limited pragmatic input in both textbooks and classroom interaction. By comparing the profiles of teachers who encouraged L2 requests with those who did not, the study offers new explanations for L2 learners’ limited pragmatic development which also broadly corroborate previous findings of somewhat limited potential for L2 pragmatic development in obligatory school contexts

On the analysis of big data indexing execution strategies

Efficient response to search queries is very crucial for data analysts to obtain timely results from big data spanned over heterogeneous machines. Currently, a number of big-data processing frameworks are available in which search operations are performed in distributed and parallel manner. However, implementation of indexing mechanism results in noticeable reduction of overall query processing time. There is an urge to assess the feasibility and impact of indexing towards query execution performance. This paper investigates the performance of state-of-the-art clustered indexing approaches over Hadoop framework which is de facto standard for big data processing. Moreover, this study leverages a comparative analysis of non-clustered indexing overhead in terms of time and space taken by indexing process for varying volume data sets with increasing Index Hit Ratio. Furthermore, the experiments evaluate performance of search operations in terms of data access and retrieval time for queries that use indexes. We then validated the obtained results using Petri net mathematical modeling. We used multiple data sets in our experiments to manifest the impact of growing volume of data on indexing and data search and retrieval performance. The results and highlighted challenges favorably lead researchers towards improved implication of indexing mechanism in perspective of data retrieval from big data. Additionally, this study advocates selection of a non-clustered indexing solution so that optimized search performance over big data is obtained