3,388 research outputs found
Scientometric portrait of Ram Gopal Rastogi
No full textPublication productivity of Indian scientist (R.G. Rastogi) has been documented.
Scientometric analysis of 312 papers by Ram Gopal Rastogi published during 1954 to 1992 in various domains: (a) Luni -solar activity and quiet -time E & F- region (57); (b) Equatorial electric field and low and mid latitude iof:osphere (78); (c) Ionospheric E- region irregularities (19); (dj Ionospheric F- region irregularities (32); and (e) Magnetic disturbance effects on the equatorial low and mid latitude ionosphere (23) were analysed. Interdomainery contents and of the number of papers: a+b were 36; b+c and b+d were 20 each; b+e were 16;. c+e were 5; a+e were 3; d+e were 2; and a+d had only one publication. Highest collaborations were with H. Chandra (61), M.R. Deshpande (42), and G. Sethia (19) out of his total 97 collaborators. His highest productivity was during 1978 with 28 papers followed by 19 papers during 1977. The core journals preferred by him for publishing papers were: Indian Journal of Radio & Space Physics, India, and Journal of Atomic & Terrestrial Physics, UK (59 each), followed by Proceedings of the Indian Academy of Sciences, India (34). Most prolific title keywords with their frequencies were: Ionosphere (92); Equatorial (61); F-region (53); Equatorial electrojet region (40), and Magnetic equator (30)
Remark on <i>p</I>-<i>d< Operator
No full textGopal, Dhananjay/0000-0001-8217-2778In this short communication, we show that P-D, operator fall in the class of weakly compatible (respectively, occasionally weakly compatible) in the presence of a unique common fixed point (respectively, multiple common fixed points) of the given maps.CSIR, Govt. of India [25(0215)/13/EMR-II]The first author thanks for the support of CSIR, Govt. of India, Grant No.25(0215)/13/EMR-II.Emerging Sources Citation Inde
Suzuki type fuzzy -contractive mappings and fixed points in fuzzy metric spaces
No full textsummary:In this paper, we propose the concept of Suzuki type fuzzy -contractive mappings, which is a generalization of Fuzzy -contractive mappings initiated in the article [S. Shukla, D. Gopal, W. Sintunavarat, A new class of fuzzy contractive mappings and fixed point theorems, Fuzzy Sets and Systems 350 (2018)85-95]. For this type of contractions suitable conditions are framed to ensure the existence of fixed point in -complete as well as -complete fuzzy metric spaces. A comprehensive set of examples are furnished to demonstrate the validity of the obtained results
Experimental investigation of the seismic performance of caisson foundations supporting bridge piers
No full textAllowing the transitory attainment of bearing capacity of caisson foundations supporting bridge piers during strong seismic events can lead to substantial optimisation in their design and major cost savings. If the approach of Capacity Design is applied to geotechnical systems, the temporary triggering of plastic mechanisms may be permitted if the resulting permanent displacements are smaller than given threshold values. To validate this design approach, the seismic performance of caisson foundations was assessed through dynamic centrifuge testing on reduced-scale models. This paper presents the results of two tests in which a caisson-pier-deck system was embedded in a typical alluvial deposit and subjected to a series of earthquakes of different intensities. The caissons were founded on soft and very soft clay, to either avoid or induce the attainment of plastic soil behaviour under the same seismic inputs. It is shown that both yielding and failure of the layer of very soft clay limit inertial forces transmitted to the superstructure, validating the design approach and some useful empirical relations available in the literature. On the other hand, inelastic soil behaviour implies accumulation of permanent rotation and settlement of the system, which must be carefully evaluated to check for fulfilment of performance requirements
Time-Message Trade-Offs in Distributed Algorithms
No full textThis paper focuses on showing time-message trade-offs in distributed algorithms for fundamental problems such as leader election, broadcast, spanning tree (ST), minimum spanning tree (MST), minimum cut, and many graph verification problems. We consider the synchronous CONGEST distributed computing model and assume that each node has initial knowledge of itself and the identifiers of its neighbors - the so-called KT_1 model - a well-studied model that also naturally arises in many applications. Recently, it has been established that one can obtain (almost) singularly optimal algorithms, i.e., algorithms that have simultaneously optimal time and message complexity (up to polylogarithmic factors), for many fundamental problems in the standard KT_0 model (where nodes have only local knowledge of themselves and not their neighbors). The situation is less clear in the KT_1 model. In this paper, we present several new distributed algorithms in the KT_1 model that trade off between time and message complexity.
Our distributed algorithms are based on a uniform and general approach which involves constructing a sparsified spanning subgraph of the original graph - called a danner - that trades off the number of edges with the diameter of the sparsifier. In particular, a key ingredient of our approach is a distributed randomized algorithm that, given a graph G and any delta in [0,1], with high probability constructs a danner that has diameter O~(D + n^{1-delta}) and O~(min{m,n^{1+delta}}) edges in O~(n^{1-delta}) rounds while using O~(min{m,n^{1+delta}}) messages, where n, m, and D are the number of nodes, edges, and the diameter of G, respectively. Using our danner construction, we present a family of distributed randomized algorithms for various fundamental problems that exhibit a trade-off between message and time complexity and that improve over previous results. Specifically, we show the following results (all hold with high probability) in the KT_1 model, which subsume and improve over prior bounds in the KT_1 model (King et al., PODC 2014 and Awerbuch et al., JACM 1990) and the KT_0 model (Kutten et al., JACM 2015, Pandurangan et al., STOC 2017 and Elkin, PODC 2017):
1) Leader Election, Broadcast, and ST. These problems can be solved in O~(D+n^{1-delta}) rounds using O~(min{m,n^{1+delta}}) messages for any delta in [0,1].
2) MST and Connectivity. These problems can be solved in O~(D+n^{1-delta}) rounds using O~(min{m,n^{1+delta}}) messages for any delta in [0,0.5]. In particular, for delta = 0.5 we obtain a distributed MST algorithm that runs in optimal O~(D+sqrt{n}) rounds and uses O~(min{m,n^{3/2}}) messages. We note that this improves over the singularly optimal algorithm in the KT_0 model that uses O~(D+sqrt{n}) rounds and O~(m) messages.
3) Minimum Cut. O(log n)-approximate minimum cut can be solved in O~(D+n^{1-delta}) rounds using O~(min{m,n^{1+delta}}) messages for any delta in [0,0.5].
4) Graph Verification Problems such as Bipartiteness, Spanning Subgraph etc. These can be solved in O~(D+n^{1-delta}) rounds using O~(min{m,n^{1+delta}}) messages for any delta in [0,0.5]
Biodiversity in Wetlands: assessment, function and conservation. Vol. 1
No full textPreface (B. Gopal, W.J. Junk, J.A. Davis) Biodiversity in wetlands: an introduction. B. Gopal, W.J.Junk The importance of stream-wetland-systems for biodiversity. K.M. Wantzen, W.J. Junk Riverine wetlands and biodiversity conservation in tropical Asia. D. Dudgeon Fish biodiversity in floodplains and their associated rivers. R.L. Welcomme Biodiversity in high Paran River floodplain. A.A. Agostinho, S.M. Thomaz, C.V. Minte-Vera, K.O. Winemiller Mechanisms for development and maintenance of biodiversity in neotropical floodplains. W.J. Junk Biodiversity of a Danubian floodplain: structural, functional and compositional aspects. K. Tockner, C. Baumgartner, F. Schiemer, J.V. Ward Determinants of avian diversity in neotropical mangrove forests. G. Lefebrvre, B. Poulin Biodiversity in wetlands of dry regions. L. Brendonck, W.D. Williams Floristic diversity inthe Okavango Delta, Botswana as an endogenous product of biological activity. W.N. Ellery, T.S. McCarthy, J.M. Dangerfield Karst wetlands biodiversity and continuity through major climatic change: an example from arid tropical Western Australia. W.F. Humphreys Biodiversity of Estonian wetlands. V. Masing, J. Paal, A. Kuresoo Bacterial biodiversity in wetlands. P.I. Boon Restoration of biodiversity to costal and inland wetlands. J.B. Zedler International mechanisms for the conservation and sustainable use of wetlands. D.M.Bartle
FIGURE 1. Ceropegia kumaonensis Kamal Kishor, G.S. Rawat & S.S. Samant a–c in A New Species of Ceropegia L. (Apocynaceae) from Uttarakhand, Western Himalaya, India
No full textFIGURE 1. Ceropegia kumaonensis Kamal Kishor, G.S. Rawat & S.S. Samant a–c. Habit; d&e. Inflorescence and flowers; f. Follicles and seeds; g&h. Corona.Published as part of Kishor, Kamal, Rawat, Gopal S. & Samant, Sher S., 2022, A New Species of Ceropegia L. (Apocynaceae) from Uttarakhand, Western Himalaya, India, pp. 85-90 in Phytotaxa 571 (1) on page 86, DOI: 10.11646/phytotaxa.571.1.7, http://zenodo.org/record/727054
Blocking Independent Sets for H-Free Graphs via Edge Contractions and Vertex Deletions
No full textLet d and k be two given integers, and let G be a graph. Can we reduce the independence number of G by at least d via at most k graph operations from some fixed set S? This problem belongs to a class of so-called blocker problems. It is known to be co-NP-hard even if S consists of either an edge contraction or a vertex deletion. We further investigate its computational complexity under these two settings: we give a sufficient condition on a graph class for the vertex deletion variant to be co-NP-hard even if d=k=1d=k=1 ; in addition we prove that the vertex deletion variant is co-NP-hard for triangle-free graphs even if d=k=1d=k=1 ; we prove that the edge contraction variant is NP-hard for bipartite graphs but linear-time solvable for trees. By combining our new results with known ones we are able to give full complexity classifications for both variants restricted to H-free graphs. D. Paulusma received support from EPSRC (EP/K025090/1)
FIGURE 2 in Asystasia venui (Justicieae: Acanthaceae): A new species from West Bengal, India
No full textFIGURE 2. Asystasia venui: A. Habit; B. Leaves; C. Front view of flower; D. Bract; E. Bracteoles; F. Dorsal view of calyx splits open; G. Ventral view of calyx splits open; H. Lateral view of corolla with calyx; I. Dorsal view of corolla splits open; J. Ventral view of corolla splits open; K. One pair of stamens; L. Style with calyx; M. Ovary; N. Disc; O. Fruits; P. Seeds. (Photographed by Anant Kumar)Published as part of Kumar, Anant, Krishna, Gopal & Bhattacharjee, Avishek, 2023, Asystasia venui (Justicieae: Acanthaceae): A new species from West Bengal, India, pp. 239-247 in Phytotaxa 600 (4) on page 242, DOI: 10.11646/phytotaxa.600.4.3, http://zenodo.org/record/809394
FIGURE 1. Garcinia stipulata T in Second-step lectotypification of Garcinia stipulata (Clusiaceae) and its recollection from Darjeeling-Sikkim Himalaya, India
No full textFIGURE 1. Garcinia stipulata T. Anderson (A) Male inflorescence twig. (B) Sepal. (C) Petal. (D) Annular mass of stamens. (E) Pistillode after removing stamens. (F) Anther. (G) Female twig with fruit. (H) Female flower bud. (I) Female flower showing sepals, ovary and peltate stigma without petals.Published as part of Ranjan, Vinay, Kumar, Anant & Krishna, Gopal, 2022, Second-step lectotypification of Garcinia stipulata (Clusiaceae) and its recollection from Darjeeling-Sikkim Himalaya, India, pp. 118-124 in Phytotaxa 577 (1) on page 119, DOI: 10.11646/phytotaxa.577.1.5, http://zenodo.org/record/751756
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