881 research outputs found
Brief Announcement: Non-Blocking Dynamic Unbounded Graphs with Worst-Case Amortized Bounds
No full textThis paper reports a new concurrent graph data structure that supports updates of both edges and vertices and queries: Breadth-first search, Single-source shortest-path, and Betweenness centrality. The operations are provably linearizable and non-blocking
Non-Blocking Dynamic Unbounded Graphs with Worst-Case Amortized Bounds
No full textThis paper reports a new concurrent graph data structure that supports updates of both edges and vertices and queries: Breadth-first search, Single-source shortest-path, and Betweenness centrality. The operations are provably linearizable and non-blocking. © Bapi Chatterjee, Sathya Peri, and Muktikanta Sa; licensed under Creative Commons License CC-BY 4.
Replication Data for: Bird’s Decision to Shift the Direction of Migration Path Depends on the Position of Sun as well as Moon: A Directional Statistical Inference
No full textDataset for: Bird’s Decision to Shift the Direction of Migration
Path Depends on the Position of the Sun as well as Moon:
A Directional Statistical Inference
(Author: Prithwish Ghosh, Debashis Chatterjee, Amlan Banerjee
Tea Tales – India’s ever evolving chai culture
No full textAs we observed International Tea Day on May 21, to peek into the vibrant history of chai and chai tapris in India, Village Square spoke to Arup K Chatterjee, professor of English at OP Jindal Global University. He is the author of widely acclaimed books including, The Purveyors of Destiny: A Cultural Biography of the Indian Railways and The Great Indian Railways
Non-Blocking Dynamic Unbounded Graphs with Worst-Case Amortized Bounds
No full textToday’s graph-based analytics tasks in domains such as blockchains, social networks, biological networks, and several others demand real-time data updates at high speed. The real-time updates are efficiently ingested if the data structure naturally supports dynamic addition and removal of both edges and vertices. These dynamic updates are best facilitated by concurrency in the underlying data structure. Unfortunately, the existing dynamic graph frameworks broadly refurbish the static processing models using approaches such as versioning and incremental computation. Consequently, they carry their original design traits such as high memory footprint and batch processing that do not honor the real-time changes. At the same time, multi-core processors-a natural setting for concurrent data structures-are now commonplace, and the analytics tasks are moving closer to data sources over lightweight devices. Thus, exploring a fresh design approach for real-time graph analytics is significant.
This paper reports a novel concurrent graph data structure that provides breadth-first search, single-source shortest-path, and betweenness centrality with concurrent dynamic updates of both edges and vertices. We evaluate the proposed data structure theoretically - by an amortized analysis - and experimentally via a C++ implementation. The experimental results show that (a) our algorithm outperforms the current state-of-the-art by a throughput speed-up of up to three orders of magnitude in several cases, and (b) it offers up to 80x lighter memory-footprint compared to existing methods. The experiments include several counterparts: Stinger, Ligra and GraphOne. We prove that the presented concurrent algorithms are non-blocking and linearizable
6 Indians who helped make London the city it is today
No full textArup K Chatterjee, author of Indians in London, tells us about the Indian people who came to London and changed it — as well as Britain and the world — for good
Cumellana Petrescu, Chatterjee & Schizas, 2012, gen. nov.
No full textCumellana gen. nov. Diagnosis. Female. Carapace without antennal notch. Antenna 1 long, second article of peduncle without tubercle. Labium with a forked terminal seta. Maxilliped 1 with large dactylus. Maxilliped 3 with long propodus, twice as long as carpus. Pereopod 1 dactylus with short terminal setae. Pereopod 2 dactylus with three terminal short setae, middle one highly robust. Male unknown. Etymology. The name is a combination between the generic name Cumella and the Christian name of the daughter of first author, Ana. Type species. Cumellana caribbica sp. nov. Remarks. The new genus could be distinguished from other genera of the family Nannastacidae by having long antennules and pereopod 2 with short terminal setae, equal in length.Published as part of Petrescu, Iorgu, Chatterjee, Tapas & Schizas, Nikolaos V., 2012, New genus and new species of Cumacea (Crustacea: Peracarida) from the mesophotic coral ecosystem of SW Puerto Rico, Caribbean Sea, pp. 55-61 in Zootaxa 3476 on page 58, DOI: 10.5281/zenodo.21129
Copidognathus gurui Chatterjee & Pešić 2014, sp. nov.
No full text<i>Copidognathus gurui</i> sp. nov. <p>(Figs. 1­ 4)</p> <p> <b>Material examined.</b> Holotype (female), paratype (female), and additional materials ­ two females used for SEM, Matemwe (05 o 52'S, 39 o 21'E) the east coast of Unguja, Zanzibar, Tanzania in coral rubble of <i>Fungia</i> (Anthozoa, Scleractinia), August 17 th 2004, coll. M Raes & H Gheerardyn.</p> <p> <b>Description</b></p> <p> Female. Idiosoma 295­ 317 (holotype: 317) µm long. AD 104­ 111 (holotype: 106) µm long. Anterior half of AD joining with dorsal part of AE. AD with frontal process and three areolae. Anterior areola oblong; paired crescent shaped middle areolae with 18­ 20 rosette pores each. Paired ds 1 anterior to middle areolae on AD. Pair of gland pores lie near anterolateral margin of AD anterior to ds 1. Area between areolae comperises large sized panels (panels not subdivided). Posterior margin of AD with a ridge containing a row of panels, each panel subdivided comprising four to eight small shallow subpanels. OC 82­ 84 µm long, 51­ 56 µm width, length to width ratio about 1.6, each with two corneae, areolae with rosette pores medial to corneae and posterolateral to posterior cornea; gland pore lateral to posterior cornea adjacent to lateral margin of OC; pore canaliculus present adjacent to lateral margin of OC. Setae ds 2 located at anteromedial corner of OC. PD 173 – 193 (holotype: 193) µm long. PD with two middle and two lateral costae. Each middle costae about 16 µm wide: with one to two rosette pores (each rosette pore with prominent ostium and canaliculi in and around it) and with panels lateral to it (each panel subdivided comprising subpanels) (Figs. 1D, 3E, F). Anterior part of middle costae and lateral costae joined together with panels (each panel with subpanels). Area between two middle costae three to six panels wide, panels not subdivided (devoid of subpanels). Setae ds 3 – ds 5 on PD. Gland pores lateral to middle costae on posterior part of PD. AE with three pairs of ventral setae and a pair of epimeral pores. Paired ventrolateral areolae between insertion of legs I and II, paired marginal areolae posterior to insertion of leg II. PE with three ventral and one dorsal seta. GA 150­ 153 (holotype: 151) µm long, GO 50­ 59 (holotype: 52) µm long. Distance between anterior end of GO and that of GA subequal to GO length. Paragenital areolae well developed. Three pairs of PGS present. In holotype anterior PGS 22 µm anterior to anterior end of GO; middle pair of PGS posterior to anterior margin of GO, 32 µm apart from lateral margin of GA; third pair near posterior side of GO. Pair of SGS located at the anterior end of genital sclerites.</p> <p> Gnathosoma 83 ­ 93 µm long. Palp consisting of four segments. Tip of rostrum just passing distal end of P 3. P 1 and P 3 devoid of any seta. P 2 with one dorsal seta distally. P 4 with three long proximal seta and one minute distal seta. Proto and deutorostral seta situated at the tip of rostrum; tritorostral setae (long maxillary setae of rostrum) located at 0.35 of rostrum length from its tip. Gnathosomal base with a pair of setae (basirostral setae). Rostral sulcus long extends posteriorly just beyond the tritorostral seta.</p> <p>Chaetotaxy of legs: trochanters I­IV, 1­ 1­ 1­ 0; basifemora I­IV, 2­ 2­ 2­ 2; telofemora I­IV, 5­ 5­ 3­ 3; genua I­IV, 4­ 4­ 3­ 3; tibiae I­IV, 7­ 7­ 5­ 5; tarsi I­IV (PAS excluded), 7­ 4­ 4­ 3. Telofemora III­IV with two dorsal setae and one ventral seta. Telofemur I swollen with well developed trilobed ventrolateral lamella. Tibia I with three ventral setae (one long, pointed ventral seta and two thick, smaller ventromedial setae). Tibia II with one long, pointed ventral seta and two thick, pectinate ventromedial setae. Tibia III with one thick, pectinate ventromedial seta. All setae of tibia IV smooth. Tibia I with two denticulate proximoventral processes (lamella) (Fig. 1E). Tibia II with a feebly developed (not clear properly) proximoventral process. Tarsus I with three dorsal setae, one solenidion, three ventral setae and two eupathidial doublet PAS. Tarsus II with three dorsal setae, one solenidion; PAS obscured by specimen compression. Tarsus III with four dorsal setae (distance between two basidorsal setae a little less than height of the segment) and two PAS. Tarsus IV with three dorsal setae and two PAS. All legs with two lateral claws and one bidentate median claw. Lateral claws with accessory process dorsally. Lateral claws of tarsi II­IV with ventral pecten.</p> <p> <b>Etymology.</b> The species is dedicated in honor of Prof. B. C. Guru, Utkal University, Bhubaneswar, Orissa, India, thesis advisor (in D. Sc.) of first author (TC).</p> <p> <b>Remarks.</b> <i>Copidognathus gurui</i> sp. nov. is characterized by two crescent shaped middle areolae on anterior dorsal plate, ds 2 on anteromedian corner of OC, a swollen telofemur I with a trilobed ventrolateral lamella, tibia I with two denticulate proximoventral processes, tarsi III and IV with 4:3 dorsal setae, telofemora III and IV each with one ventral seta.</p> <p> Present new species has some similarity with <i>C. punctatissimus</i> (Gimbel, 1919), <i>C. dentatus</i> Viets, 1940, <i>C. biscayneus</i> Newell, 1947, <i>C. dentipes</i> Bartsch, 1989, <i>C. eblingi</i> Chatterjee, 1991, <i>C. jejuensis</i> Chatterjee & Chang, 2004 and <i>C. mumbaiensis</i> Chatterjee & Chang, 2004. <i>C. tupinamborum</i> Pepato & Tiago, 2005 (Gimbel 1919; Newell 1947; Bartsch 1989; Chatterjee 1991; Chatterjee and Annapurna 2003, Chatterjee and Chang 2004a, b, 2006; Pepato and Tiago 2005).</p> <p> <i>C. punctatissimus</i> has ds 2 located on anteromedial corner of OC as in <i>C. gurui</i> sp. nov. while in all of the other aforementioned species ds 2 are located in the membranous cuticular area between AD and OC. <i>Copidognathus gurui</i> sp. nov. differs from <i>C. punctatissimus</i> and all other species in having a well developed trilobed ventrolateral lamella on telofemur I.</p> <p> <i>Copidognathus mumbaiensis</i> is characterised by the presence of a serrated lamella ventrolaterally on telofemur I instead of trilobed lamella.</p>Published as part of <i>Chatterjee, Tapas & Pešić, Vladimir, 2014, A new species of the genusCopidognathus (Acari, Halacaridae) from Zanzibar, Tanzania, pp. 169-175 in Ecologica Montenegrina 1 (3)</i> on pages 170-17
Ruminations of a Gandhian: Margaret Chatterjee
No full text This article is based on conversations the author had with nonagenarian Gandhian, Margaret Chatterjee, over the last one year. It is reflective of Chatterjee’s engagement with Gandhian philosophy—non-violence and satyagraha, drawn from influences in Gandhi’s life—and captures why she rejects the categorization of Gandhi as either a traditionalist or a modernist. </jats:p
Lock-free linearizable 1-dimensional range queries
No full text\ua9 2016 ACM.Efficient concurrent data structures that support range queries are highly sought-after in a number of application areas. For example, the contemporary big-data processing platforms employ them as in-memory index structures for fast and scalable real-time updates and analytics, where analytics utilizes the range queries. In this paper, we present a generic algorithm to perform linearizable range queries in lock-free ordered 1-dimensional data structures. The algorithm requires single-word atomic compare-and-swap (CAS) primitives. Our method generalizes the lock-free data structure snapshot of Petrank et al. [25]. Fundamentally, we utilize a partial snapshot object derived from the snapshot object of Jayanti [20]. We experimentally evaluate the proposed algorithm in a lock-free linked-list, skip-list and binary search tree (BST). The experiments demonstrate that our algorithm is scalable even in the presence of high percentage of concurrent modify operations and outperforms an existing range search algorithm in lock-free k-ary trees in several scenarios
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