•AMR Graphs are based upon PropBanks which limits them.•Deep Learning Models capture both the syntactic and semantic structure.•Requirement of large data set limits the use of Deep Learning ...Models.•Need of generalized framework for abstractive summaries is the need of time.
Summarization, is to reduce the size of the document while preserving the meaning, is one of the most researched areas among the Natural Language Processing (NLP) community. Summarization techniques, on the basis of whether the exact sentences are considered as they appear in the original text or new sentences are generated using natural language processing techniques, are categorized into extractive and abstractive techniques. Extractive summarization has been a very extensively researched topic and has reached to its maturity stage. Now the research has shifted towards the abstractive summarization. The complexities underlying with the natural language text makes abstractive summarization a difficult and a challenging task.
This paper presents a comprehensive review of the various works performed in abstractive summarization field. For this purpose, we have selected the recent papers on this topic from Elsevier, ACM, IEEE, Springer, ACL Anthology, Cornell University Library and Google Scholar. The papers are categorized according to the type of abstractive technique used. The paper lists down the various challenges and discusses the future direction for research in this field. Along with these, we have identified the advantages and disadvantages of various methods used for abstractive summarization. We have also listed down the various tools which have been used or developed by researchers for abstractive summarization. The paper also discusses the evaluation techniques being used for assessing the abstractive summaries.
Carbon nanotubes (CNT) represent one of the most unique materials in the field of nanotechnology. CNT are the allotrope of carbon having sp2 hybridization. CNT are considered to be rolled-up graphene ...with a nanostructure that can have a length to diameter ratio greater than 1,000,000. CNT can be single-, double-, and multi-walled. CNT have unique mechanical, electrical, and optical properties, all of which have been extensively studied. The novel properties of CNT are their light weight, small size with a high aspect ratio, good tensile strength, and good conducting characteristics, which make them useful for various applications. The present review is focused on the structure, properties, toxicity, synthesis methods, growth mechanism and their applications. Techniques that have been developed to synthesize CNT in sizeable quantities, including arc discharge, laser ablation, chemical vapor deposition, etc., have been explained. The toxic effect of CNT is also presented in a summarized form. Recent CNT applications showing a very promising glimpse into the future of CNT in nanotechnology such as optics, electronics, sensing, mechanical, electrical, storage, and other fields of materials science are presented in the review.
In the present paper we develop an algorithm for all spherically symmetric anisotropic charged fluid distributions. Considering a new source function
ν
(
r
)
we find a set of solutions which is ...physically well behaved and represents compact stellar models. A detailed study specifically shows that the models actually correspond to strange stars in terms of their mass and radius. In this connection we investigate several physical properties like energy conditions, stability, mass–radius ratio, electric charge content, anisotropic nature and surface redshift through graphical plots and mathematical calculations. All the features from these studies are in excellent agreement with the already available evidence in theory as well as observations.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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•Synthesis of material is done by sol-gel method which is easy and cost effective.•SEM shows that the film is macro porous and porosity lies in range of 50–100nm.•Minimum particle ...size calculated by TEM is 6.7nm.•The LPG sensing of barium titante film below LEL was performed for the first time at room temperature.•The value of maximum sensitivity was found 3.5 and % sensor response was found 250 for 4 vol. % LPG.
Perovskite barium titanate (BaTiO3) nanocomposite thin film has been prepared using spin coating technique. Surface morphological, structural, compositional and optical properties of the film were investigated by various techniques such as SEM, XRD, TEM, EDS, UV-Spectroscopy, Raman spectroscopy and FTIR. SEM images showed the macroporous cubic structure of the film. The minimum crystallite size was evaluated as 11nm by XRD and confirmed by TEM. Band gap of BaTiO3 was evaluated as 3.9eV. Raman Spectroscopy confirmed the formation of BaTiO3 at 540cm−1. LPG sensings were carried out for vol.% 0.5–4 of LPG and sensor was found robust for the detection of LEL for LPG also.
The GRAPES-3 muon telescope located in Ooty, India records rapid (∼10 min) variations in the muon intensity during major thunderstorms. Out of a total of 184 thunderstorms recorded during the ...interval of April 2011-December 2014, the one on December 1, 2014 produced a massive potential of 1.3 GV. The electric field measured by four well-separated (up to 6 km) monitors on the ground was used to help estimate some of the properties of this thundercloud, including its altitude and area that were found to be 11.4 km above mean sea level and ≥380 km^{2}, respectively. A charging time of 6 min to reach 1.3 GV implied the delivery of a power of ≥2 GW by this thundercloud that was moving at a speed of ∼60 km h^{-1}. This work possibly provides the first direct evidence for the generation of gigavolt potentials in thunderclouds that could also possibly explain the production of highest-energy (100 MeV) gamma rays in the terrestrial gamma-ray flashes.
Generalised model for anisotropic compact stars Maurya, S. K.; Gupta, Y. K.; Ray, Saibal ...
European physical journal. C, Particles and fields,
12/2016, Letnik:
76, Številka:
12
Journal Article
Recenzirano
Odprti dostop
In the present investigation an exact generalised model for anisotropic compact stars of embedding class 1 is sought with a general relativistic background. The generic solutions are verified by ...exploring different physical aspects, viz. energy conditions, mass–radius relation, stability of the models, in connection to their validity. It is observed that the model presented here for compact stars is compatible with all these physical tests and thus physically acceptable as far as the compact star candidates
RXJ
1856-37,
SAX
J
1808.4-3658 (
SS
1) and
SAX
J
1808.4-3658 (
SS
2) are concerned.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this article we obtain a new anisotropic solution for Einstein’s field equations of embedding class one metric. The solution represents realistic objects such as
Her X-1
and
RXJ 1856-37
. We ...perform a detailed investigation of both objects by solving numerically the Einstein field equations with anisotropic pressure. The physical features of the parameters depend on the anisotropic factor i.e. if the anisotropy is zero everywhere inside the star then the density and pressures will become zero and the metric turns out to be flat. We report our results and compare with the above mentioned two compact objects as regards a number of key aspects: the central density, the surface density onset and the critical scaling behaviour, the effective mass and radius ratio, the anisotropization with isotropic initial conditions, adiabatic index and red shift. Along with this we have also made a comparison between the classical limit and theoretical model treatment of the compact objects. Finally we discuss the implications of our findings for the stability condition in a relativistic compact star.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Anisotropic models for compact stars Maurya, S. K.; Gupta, Y. K.; Ray, Saibal ...
The European physical journal. C, Particles and fields,
05/2015, Letnik:
75, Številka:
5
Journal Article
Recenzirano
Odprti dostop
In the present paper we obtain an anisotropic analog of the Durgapal and Fuloria (Gen Relativ Gravit 17:671,
1985
) perfect fluid solution. The methodology consists of contraction of the anisotropic ...factor
Δ
with the help of both metric potentials
e
ν
and
e
λ
. Here we consider
e
λ
the same as Durgapal and Fuloria (Gen Relativ Gravit 17:671,
1985
) did, whereas
e
ν
is as given by Lake (Phys Rev D 67:104015,
2003
). The field equations are solved by the change of dependent variable method. The solutions set mathematically thus obtained are compared with the physical properties of some of the compact stars, strange star as well as white dwarf. It is observed that all the expected physical features are available related to the stellar fluid distribution, which clearly indicates the validity of the model.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•We studied the effect of tillage and residue management on SOC stabilization in soil aggregates and yield attribute.•Reduced and zero tillage in wheat coupled with DSR increased 50.13% ...macroaggregates than conventional tillage.•Residue application increased 15.65% total water stable aggregates in surface soil.•DSR+ZT+WRR/WZT+RRR increased SOC by 33.6%, EWY by 8.3% and macroaggregate associated C by 20.8% than TPR/CWS.•DSR+ZT+WRR/WZT+RRR is preferable to sequester C in semi-arid Indian sandy loam soil with sustainable yield increment.
Conservation tillage and residue management are the options for enhancing soil organic carbon stabilization by improving soil aggregation in tropical soils. We studied the influence of different combinations of tillage and residue management on carbon stabilization in different sized soil aggregates and also on crop yield after 5 years of continuous rice–wheat cropping system on a sandy loam reclaimed sodic soil of north India. Compared to conventional tillage, water stable macroaggregates in conservation tillage (reduced and zero-tillage) in wheat coupled with direct seeded rice (DSR) was increased by 50.13% and water stable microaggregates of the later decreased by 10.1% in surface soil. Residue incorporation caused a significant increment of 15.65% in total water stable aggregates in surface soil (0–15cm) and 7.53% in sub-surface soil (15–30cm). In surface soil, the maximum (19.2%) and minimum (8.9%) proportion of total aggregated carbon was retained with >2mm and 0.1–0.05mm size fractions, respectively. DSR combined with zero tillage in wheat along with residue retention (T6) had the highest capability to hold the organic carbon in surface (11.57gkg−1 soil aggregates) with the highest stratification ratio of SOC (1.5). Moreover, it could show the highest carbon preservation capacity (CPC) of coarse macro and mesoaggregates. A considerable proportion of the total SOC was found to be captured by the macroaggregates (>2–0.25mm) under both surface (67.1%) and sub-surface layers (66.7%) leaving rest amount in microaggregates and ‘silt+clay’ sized particles. From our study, it has been proved that DSR with zero tillage in wheat (with residue) treatment (T6) has the highest potential to secure sustainable yield increment (8.3%) and good soil health by improving soil aggregation (53.8%) and SOC sequestration (33.6%) with respect to the conventional tillage with transplanted rice (T1) after five years of continuous rice–wheat cropping in sandy loam reclaimed sodic soil of hot semi-arid Indian sub-continent.
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