Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. Damanjit Kaur. Articles written in Journal of Chemical Sciences. Volume 112 Issue 6 December 2000 pp 623-629 Physical and Theoretical. Theoretical studies on the conformations of selenamides · Rajnish Moudgil Damanjit Kaur Rachita Vashisht Prasad V Bharatam.

Sadhana | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Sadhana. MANPREET KAUR. Articles written in Sadhana. Volume 41 Issue 12 December 2016 pp 1463-1472. Stokes flow of micropolar fluid past a viscous fluid spheroid with non-zero boundary condition for microrotation · M KRISHNA PRASAD MANPREET KAUR · More Details Abstract Fulltext PDF.

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. Navneet Kaur. Articles written in Journal of Chemical Sciences. Volume 126 Issue 1 January 2014 pp 49-54. Anthraquinone-based demultiplexer and other multiple operations at the molecular level · Navneet Kaur Subodh Kumar · More Details Abstract Fulltext PDF.

Journal of Genetics | Indian Academy of Sciences

Indian Academy of Sciences (India)

Author Affiliations. NEHA SUDHIR1 TAJINDER KAUR2 ARCHANA BERI3 ANUPAM KAUR1. Department of Human Genetics, Guru Nanak Dev University, Amritsar 143 005, India; Hartej Hospital and Nursing Home, Amritsar 143 005, India; Beri Maternity Hospital, Southend Beri Fertility and IVF, Amritsar 143 005, India ...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. Aruna Bhatia. Articles written in Journal of Chemical Sciences. Volume 123 Issue 4 July 2011 pp 443-451. Synthesis of 4-aryl-4,5-dihydro-1-indeno[1,2-]pyrimidines by Biginelli condensation and their antibacterial activities · Ramandeep Kaur Monika Bansal Balbir Kaur ...

Journal of Genetics | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Genetics. PARVEEN CHHUNEJA. Articles written in Journal of Genetics. Volume 91 Issue 2 August 2012 pp 155-161 Research Article. Introgression of a leaf rust resistance gene from Aegilops caudata to bread wheat · Amandeep Kaur Riar Satinder Kaur H. S. Dhaliwal Kuldeep Singh Parveen ...

India's Urban war: Through the Smoke

DEFF Research Database (Denmark)

Kaur, Ravinder

2008-01-01

The assimilation of India's urban terror attacks into a global narrative of Islamist violence carries the danger that their domestic social and historical roots will be missed, says Ravinder Kaur.......The assimilation of India's urban terror attacks into a global narrative of Islamist violence carries the danger that their domestic social and historical roots will be missed, says Ravinder Kaur....

Diversity of coprophilous species of Panaeolus (Psathyrellaceae, Agaricales) from Punjab, India

OpenAIRE

AMANDEEP KAUR; N.S. ATRI; MUNRUCHI KAUR

2014-01-01

Kaur A, Atri NS, Kaur M. 2014.Diversity of coprophilous species of Panaeolus (Psathyrellaceae, Agaricales) from Punjab, India. Biodiversitas 15: 115-130. An account of 16 Panaeolus species collected from a variety of coprophilous habitats of Punjab state in India is described and discussed. Out of these, P. alcidis, P. castaneifolius, P. papilionaceus var. parvisporus, P. tropicalis and P. venezolanus are new records for India while P. acuminatus, P. antillarum, P. ater, P. solidipes, and P. ...

Book reviews / Carolina Pihelgas, Peeter Helme and Jan Kaus

Index Scriptorium Estoniae

Pihelgas, Carolina, 1986-

2016-01-01

Arvustus: Sommer, Lauri. Kunagi: 2008-2015. Räestu [Võrumaa] : Tiivaalune, 2015 ; Rooste, Jürge. Ideaalne abikaasa. Saarde ; Pärnu : [Jumalikud Ilmutused], 2015 ; Ruitlane, Olavi. Vee peal. Tallinn : ZA/UM, 2015 ; Riismaa, Kaur. Pühamägi. Tallinn : Verb, 2015 ; Riismaa, Kaur. Pimeda mehe aiad. Tallinn : Tänapäev, 2015 ; Raud, Rein. Täiusliku lause surm. Tallinn : Mustvalge Kirjastus, 2015 ; Matsin, Paavo. Gogoli disko. Viljandi : Lepp ja Nagel, 2015 ; Lennuk, Urmas. Ükskord Eestimaal. Viljandi : Ugala Teater, 2015

Ent-kaurane diterpenoids and other constituents from the stem of Xylopia laevigata (Annonaceae)

Energy Technology Data Exchange (ETDEWEB)

Silva, Dayanne Meneses; Costa, Emmanoel Vilaca; Nogueira, Paulo Cesar de Lima; Moraes, Valeria Regina de Souza [Universidade Federal de Sergipe, Sao Cristovao, SE (Brazil). Dept. de Quimica; Cavalcanti, Socrates Cabral de Holanda [Universidade Federal de Sergipe, Sao Cristovao, SE (Brazil). Dept. de Farmacia; Salvador, Marcos Jose [Universidade Estadual de Campinas, SP (Brazil). Inst. de Biologia. Dept. de Biologia Vegetal; Ribeiro, Luis Henrique Gonzaga; Gadelha, Fernanda Ramos [Universidade Estadual de Campinas, SP (Brazil). Inst. de Biologia. Dept. de Bioquimica; Barison, Andersson [Universidade Federal do Parana, Curitiba, PR (Brazil). Dept. de Quimica; Ferreira, Antonio Gilberto, E-mail: emmanoelvc@gmail.com [Universidade Federal de Sao Carlos, SP (Brazil). Dept. de Quimica

2012-07-01

Phytochemical investigation of the hexane extract from the stem of Xylopia laevigata led to the isolation of the ent-kaurane diterpenoids, ent-kaur-16-en-19-oic acid, 4-epi-kaurenic acid, ent-16{beta}-hydroxy-17-acetoxy-kauran-19-al, ent-3{beta}-hydroxy-kaur-16-en-19-oic acid, and ent-16{beta},17-dihydroxy-kauran-19-oic acid, as well as spathulenol and a mixture of {beta}-sitosterol, stigmasterol and campesterol. The identification of the compounds was performed on the basis of spectrometric methods including GC-MS, IR, and 1D and 2D NMR. Potent larvicidal activity against Aedes aegypti larvae with LC{sub 50} of 62.7 {mu}g mL{sup -1} was found for ent-3{beta}-hydroxy-kaur-16-en-19-oic acid. This compound also showed significant antifungal activity against Candida glabrata and Candida dubliniensis with MIC values of 62.5 {mu}g mL{sup -1}. (author)

Ent-kaurane diterpenoids and other constituents from the stem of Xylopia laevigata (Annonaceae)

International Nuclear Information System (INIS)

Silva, Dayanne Meneses; Costa, Emmanoel Vilaca; Nogueira, Paulo Cesar de Lima; Moraes, Valeria Regina de Souza; Cavalcanti, Socrates Cabral de Holanda; Salvador, Marcos Jose; Ribeiro, Luis Henrique Gonzaga; Gadelha, Fernanda Ramos; Barison, Andersson; Ferreira, Antonio Gilberto

2012-01-01

Phytochemical investigation of the hexane extract from the stem of Xylopia laevigata led to the isolation of the ent-kaurane diterpenoids, ent-kaur-16-en-19-oic acid, 4-epi-kaurenic acid, ent-16β-hydroxy-17-acetoxy-kauran-19-al, ent-3β-hydroxy-kaur-16-en-19-oic acid, and ent-16β,17-dihydroxy-kauran-19-oic acid, as well as spathulenol and a mixture of β-sitosterol, stigmasterol and campesterol. The identification of the compounds was performed on the basis of spectrometric methods including GC-MS, IR, and 1D and 2D NMR. Potent larvicidal activity against Aedes aegypti larvae with LC 50 of 62.7 μg mL -1 was found for ent-3β-hydroxy-kaur-16-en-19-oic acid. This compound also showed significant antifungal activity against Candida glabrata and Candida dubliniensis with MIC values of 62.5 μg mL -1 . (author)

Química de especies del genero espeletia Espeletia killipii - Espeletia tunjana

Directory of Open Access Journals (Sweden)

Rubén Darío Torrenegra

2010-07-01

Full Text Available De las partes aéreas de 2 especies del género Espeletia se aislaron compuestos del tipo diterpeno Acido (-i-Kaur-9( 11, 16-dien-19-oico, el (-Kaur-16-en-19-ol, los terpenos friedeiina, sitosterol-estigmasterol, y dos sesquiterpenlactonas del tipo melampólido, Acetato de Longipilin y Polimatin B. Los últimos compuestos no reportados hasta el momento en la química del género Espeletia. Del extracto etanólico se identificaron dos flavonoides: Quercetina y 3-metoxiquercetina.

Terpenoid constituents from leaves of Guarea kunthiana

International Nuclear Information System (INIS)

Garcez, Fernanda R.; Garcez, Walmir S.; Bazzo, Rita de Cassia; Silva, Ana Francisca G. da; Resende, Ubirazilda M.

2004-01-01

From leaves of Guarea kunthiana one new kaurene diterpene (ent-kaur-16-en-2-one) was isolated along with eight known diterpenes (ent-kaur-16-ene, ent-3α- and 3β-hydroxykaur-16-ene, kolavelool, kolavenol, kolavenal, ent-13-epi-manoyloxide and (-)-nephthenol), four sesquiterpenes (alismol, alismoxide, spathulenol and 4β,10α-aromadendranediol), polyprenol-12 and α- and δ-tocopherols. Kolavenal is reported for the first time as a natural product, as well as the occurrence of cembrane- and ent-kaurane-type diterpenes in the Meliaceae. (author)

Investigation of origin, subsurface processes and reservoir temperature of geothermal springs around Koh-i-Sultan volcano, Chagai, Pakistan

International Nuclear Information System (INIS)

Ahmad, M.; Rafique, M.; Iqbal, N.; Fazil, M.

2009-07-01

In Chagai area, seven springs with maximum surface temperature of 32.2 deg. C located in the vicinity of Miri Crater of Koh-i-Sultan Volcano were investigated using isotope and chemical techniques. Two springs of Padagi Kaur are MgSO/sub 4/ type, while all the other springs at Batal Kaur, Miri Kaur and Chigin Dik are Na-Cl type. Alteration of water to SO/sub 4/ type takes place by absorption of magmatic H/sub 2/S and the acidic solution is further responsible to dissolve rock salt and carbonate minerals. EC increases from Padagi springs (4940 and 8170 S/cm) to Chigin Dik springs (45600 S/cm). Chagai thermal manifestations receive recharge from meteoric waters in the vicinity of Padagi Kaur (east side of Miri Crater), which is heated by the hot magma chamber of Koh-i-Sultan most probably through deep circulation. Movement of the thermal water is from Miri Crater towards Chigin Dik area. Residence time is more than 60 years. The thermal waters do not have any contribution of shallow young groundwater and they have high 1/sup 8/O-shift (6 to 8%) due to rock-water interaction. Reservoir temperatures estimated by different chemical geo thermometers like Na-K, Na-K-Ca, Na-K-Mg 1/2 (triangular plot) are quite high (200-300 deg. C), while the silica and (SO/sub 4/-H/sub 2/O) geo thermometers give relatively low temperature ranges (107-144 deg. C and 112-206 deg. C respectively). (author)

Kaalul kroonist rohkem / Max Kaur

Index Scriptorium Estoniae

Kaur, Max, 1969-

2004-01-01

Autori hinnangul tuleks eelmise rahareformiga kaasnenud paanika vältimiseks alustada ühiskonnas varakult debatti eurole üleminekuks ning avaldada sarnaselt vanadele liikmesriikidele eelnevalt hindasid nii kroonides kui eurodes

Rapla keskuse remake / Kaur Sarv

Index Scriptorium Estoniae

Sarv, Kaur

2013-01-01

2. Tallinna arhitektuuribiennaali satelliit - Rapla KEK-i hoone (Rapla Okta Centrum) taaskasutamise töötuba, selle tulemused ja ettepanekud. Töötuba aitas korraldada Hollandi urbanistide rühmitus Failed Architecture

Diversity of coprophilous species of Panaeolus (Psathyrellaceae, Agaricales from Punjab, India

Directory of Open Access Journals (Sweden)

AMANDEEP KAUR

2014-10-01

Full Text Available Kaur A, Atri NS, Kaur M. 2014.Diversity of coprophilous species of Panaeolus (Psathyrellaceae, Agaricales from Punjab, India. Biodiversitas 15: 115-130. An account of 16 Panaeolus species collected from a variety of coprophilous habitats of Punjab state in India is described and discussed. Out of these, P. alcidis, P. castaneifolius, P. papilionaceus var. parvisporus, P. tropicalis and P. venezolanus are new records for India while P. acuminatus, P. antillarum, P. ater, P. solidipes, and P. sphinctrinus are new reports for north India. Panaeolus subbalteatus and P. cyanescens are new records for Punjab state. A key to the taxa exploredis also provided.

Chemical constituents of the fruits of Copaifera langsdorffii Desf; Constituintes quimicos dos frutos de Copaifera langsdorffii Desf

Energy Technology Data Exchange (ETDEWEB)

Lima Neto, Jose de Sousa [Universidade Federal do Piaui, Teresina, PI (Brazil). Dept. de Quimica; Gramosa, Nilce Viana; Silveira, Edilberto Rocha [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Quimica Organica e Inorganica]. E-mail: nilce@dqoi.ufc.br

2008-07-01

Phytochemical investigation of the hexane extract of fruit shells of Copaifera langsdorffii Desf. (Caesalpinioideae) afforded ent-kaur-16-en-19-oic acid, polyalthic acid, nivenolide and the mixture of caryophyllene oxide and ent-kaur-16-en-19-oic acid. The chloroform extract of unripe seeds led to the isolation of coumarin and the GC/MS analysis of the extract allowed the identification of 81.8% of the fatty acid composition after hydrolysis followed by methylation. The main fatty acid identified was oleic acid (33.1%). The isolation of all secondary metabolites was accomplished by modern chromatographic methods and the structure determination was accomplished by spectrometric methods (IR, MS, NMR {sup 1}H and {sup 13}C). (author)

Organizing Committee Panel of Referees 193

Indian Academy of Sciences (India)

, Panjab University. Vipin Bhatnagar, Panjab University. M M Gupta, Panjab University. Manjit Kaur, Panjab University. C N Kumar, Panjab University. Kuldeep Kumar, Panjab University (Secretary). G Rajasekaran, IMSc, Chennai.

Eesti 3D jaoks kitsas / Virge Haavasalu

Index Scriptorium Estoniae

Haavasalu, Virge

2009-01-01

Produktsioonifirma Digitaalne Sputnik: Kaur ja Kaspar Kallas tegelevad filmide produtseerimise ning 3D digitaalkaamerate tootearendusega (Silicon Imaging LLC). Vendade Kallaste 3D-kaamerast. Kommenteerib Eesti Filmi Sihtasutuse direktor Marge Liiske

Maakera kaubamärk liitus külmhoonega / Hindrek Riikoja

Index Scriptorium Estoniae

Riikoja, Hindrek

2006-01-01

10. jaanuaril teatas Nordic Foods ettevõtte üleminekust Tallinna Külmhoone omandusse ning kolm varasemat Nordic Foodsi omanikku - Kuldar Leis, Katre Kõvask ja Silver Kaur - said osaluse Külmhoones

Tartu Jaani kiriku terrakotaskulptuurid

Index Scriptorium Estoniae

2004-01-01

10 fotot Kaur Alttoalt. Maarja võidukaare kohalt, Mooses, eestpalujad Maarja ja Ristija Johannes peaportaalilt, arvatav evangelist Johannes, portree peadefriisilt, daam tanuga, skulptuurid kesklöövi lõunaseinal, torni poolfiguur

Strandbergi imekangas tootmiseks valmis / Kaur Maran

Index Scriptorium Estoniae

Maran, Kaur

2017-01-01

Materjaliteadlased Marek Strandeberg ja Katrin Idla leiutasid kanga, millelt pinnalt radari välja kiiratud elektromagnetlained ei peegeldu tagasi ja kaitsevad nii objekte avastamise eest. Kanga eesmärgiks on muuta lennuk, tank või võitleja vaenlase radarile nähtamatuks. Senised katsetused on olnud edukad ning nüüd loodetakse kaitseministeeriumi hinnangut ja võimalikke tellimusi

"Lilja 4-everi" õppetund / Kaur Kender

Index Scriptorium Estoniae

Kender, Kaur, 1971-

2003-01-01

Suures osas Paldiskis filmitud Rootsi mängufilm "Lilja 4-ever" : režissöör Lukas Moodysson. Filmi peategelase Lilja saatuse võrdlus markii de Sade'i romaani "Justine ehk Vooruse õnnetused" nimitegelase omaga

[Konverentsi "Goethe Tartus" ettekandekogumikest] / Kairit Kaur

Index Scriptorium Estoniae

Kaur, Kairit

2001-01-01

Arvustus: Triangulum. Germanistisches Jahrbuch '99 für Estland, Lettland und Litauen. Sonderheft: Goethe. Sechste Folge / hrsg. Claus Sommerhage. Tartu, 1999 ; Eesti Goethe Seltsi aastaraamat II: Goethe Tartus : konverentsi "Goethe Tartus (1999) ettekanded. Tartu : Eesti Goethe Selts, 2000

Спортивный блок Английского колледжа, Таллинн = The sports facility of the Englich College, Tallinn / Мария Фадеева

Index Scriptorium Estoniae

Фадеева, Мария

2008-01-01

Tallinna Inglise Kolledži uuest spordihoonest. Projekt valmis firmas KOKO Arhitektid (Kaur Stöör, Margus Maiste, Andrus Kõresaar). Interjööri kujundasid Liis Lindvere, Raili Paling, Liisi Murula

Psühholoog Pulver: uskumatu. Kurb. Õõvastav / Aleksander Pulver ; intervjueerinud Tiina Jõgeda

Index Scriptorium Estoniae

Pulver, Aleksander, 1956-

2009-01-01

Vestlus Tallinna Ülikooli psühholoogia instituudi direktori Aleksander Pulveriga pedofiilia teemal. Psühholoogi seisukohavõtud laste õiguste kaitsjana ja koolihariduse uuendajana silma paistnud Kaur Hansoni pedofiiliasüüdistuste kohta

Ilmus põhjalik raamat intellektuaalsest omandist / Pirjo Ant, Kairi Kurisoo ; intervjueerinud Mari Sarv

Index Scriptorium Estoniae

Ant, Pirjo

2009-01-01

Autorid räägivad intellektuaalsest omandist ja oma raamatust: Kurisoo, Kairi ; Kaur, Viive ; Ant, Pirjo. Intellektuaalne omand. Tallinn : Äripäeva Kirjastus, 2009. (Juht ja seadus. Äripäeva raamat)

President 2001 / interv. Kai Kalamees

Index Scriptorium Estoniae

2001-01-01

Eesti Päevaleht palus erinevate elualade esindajatel hinnata presidendikandidaatide ametisse sobivust (Savi, Tarand, Kelam, Kreitzberg, Tulviste). Vastavad: Aivar Voog, Rein Ruutsoo, Kaur Hanson, Ivo Rull, Tarmo Tammerk, Mart Helme, Pavel Ivanov, Jaan Kaplinski. Diagrammid

Kaks kuud Kalev SPA-s / kommenteerinud Julia Kurbat, Natalia Nazarenko-Kiivikas, Margit Lipstuhl

Index Scriptorium Estoniae

2012-01-01

Kahe spordiharrastaja Kaur Sau ja Kadri Sõggeli seatud eesmärkidest 2012. aastal ja kehalisest arengust treenides kaks kuud mõnes Tallinna spordiklubis. Treeningutest Kalev Spa Hotel & Water Park'i nimekandvas spordi- ja vabaajakeskuses

Synthesis of a new allelopathic agent from the biotransformation of ent-15α-hydroxy-16-kauren-19-oic acid with Fusarium proliferatum.

Science.gov (United States)

Rocha, A D; Vieira, H da S; Takahashi, J A; Boaventura, M A D

2017-11-01

The use of kaurane diterpenes as substrates in fungal biotransformation to achieve bioactive compounds has been widely reported. In this work, the natural product kaurenoic acid, a diterpene widely distributed in the plant Kingdom, was chemically converted into ent-15α-hydroxy-kaur-16-en-19-oic acid (1). Substrate 1 was subjected to biotransformation by the fungus Fusarium proliferatum, furnishing a new derivative, ent-2α,15α-dihydroxy-kaur-16-en-19-oic acid (2). The structure of metabolite 2 was deduced on the basis of spectroscopy and MS data. Derivative 2 showed allelopathic activity on germination and growth of root and stem of lettuce (Lactuca sativa), inhibiting 100% of germination and growth of roots and stem, at higher concentration assayed (10 -4  mol/L).

Kuidas Sander Saarmets kosmosest maailma vallutama kipub / Moon Meier

Index Scriptorium Estoniae

Meier, Moon

2007-01-01

Eesti Muusika- ja Teatriakadeemias elektronmuusika erialal õppivast Sander Saarmetsast kui noorest heliloojast, kes on siiani oma nime teinud ulmemuusika ringkondades. Kommenteerivad sõber, muusik, ulmeplaatide boss Aivar Tõnso ja Muschraumi kitarrist Kaur Garšnek

Propagation characteristics of ion-acoustic double layer in ...

Indian Academy of Sciences (India)

Harvinder Kaur

2017-07-24

Jul 24, 2017 ... in multicomponent inhomogeneous auroral zone plasma. HARVINDER KAUR1 .... in characterizing the physics of the nonlinear waves. [49–55]. Experimental and .... (23) is due to ionization effects. In order to obtain the.

Optical, mechanical and TEM assessment of titania-doped Bi2V1 ...

Indian Academy of Sciences (India)

and mechanical parameters to their structural properties. Band gap has also ..... band absorption, Urbach tails and weak tails, which are residual below gap ..... Solids 358. 2589. Kaur G 2012c Investigations on interfacial interaction of glass.

Pramana – Journal of Physics | Indian Academy of Sciences

Indian Academy of Sciences (India)

independent search for new physics at D0 experiment · Md Naimuddin ... Precision measurement of neutrino oscillation parameters at INO-ICAL detector · Daljeet Kaur Md Naimuddin Sanjeev Kumar Verma · More Details Abstract Fulltext PDF.

Nad ikka said selle Kärdla vana elektrijaama tööle / Bianca Mikovitš

Index Scriptorium Estoniae

Mikovitš, Bianca

2009-01-01

Siret Paju lavastusest "Ei teki ega kao" Kärdla elektrijaamas. Näidendi autorid Kerli Adov, Jaan Aps, Liis Lukk, Hiri Müüripeal, Siim Nurklik ja Kaur Riismaa. Projekti käivitas MTÜ Arhipelaag eesotsas Ere Naadiga

Moodulmaja Passion M1 = Passion group prefab house / Hannelore Kääramees

Index Scriptorium Estoniae

Kääramees, Hannelore

2013-01-01

Hannelore Kääramehe (Arhitekt 11) kujundatud eramu interjöör (Haapsalu mnt. 7c, Vasalemma, Harjumaa). Hoone projekteeris Eero Endjärv (Arhitekt 11). Arhitekt Kaur Talpsepa arvamus. Lühidalt sisearhitekt Hannelore Kääramehest

Baltika Moetänav = Baltika Fashion Street

Index Scriptorium Estoniae

2010-01-01

Tallinnas Veerenni 24 asuvast Baltika Moetänava sisearhitektuursest lahendusest. Autorid: Maire Milder, Ott Kangur, Ülo-Tarmo Stöör, Maris Kerge, Kaur-Lembit Stöör, Pärtel Eelma, Pekka Porkanen, Lauri Eltermaa

Rakverlased esinesid klavessiinifestivalil

Index Scriptorium Estoniae

2008-01-01

Muusika- ja kunstikooli Kaur klavessiiniõpilased esinesid Tallinnas Eesti Teatri- ja Muusikamuuseumis kontserdil "Con spirito" VI rahvusvahelise klavessiinifestivali raames, järgmisena on Kauri kooli klavessiiniklassil plaanis osaleda EKSTi "IX ajalooliste klahvpillide suvelaagris" 25.-29. juunini Juurus

Three New Cytotoxic ent-Kaurane Diterpenes from Isodon excisoides

Directory of Open Access Journals (Sweden)

Li-Ping Dai

2015-09-01

Full Text Available Three types of ent-kaurane diterpenoids were isolated from the aerial parts of Isodon excisoides, including three new diterpenoids, 1α,7α,14β-trihydroxy-20-acetoxy-ent-kaur-15-one (1; 1α,7α,14β,18-tetrahydroxy-20-acetoxy-ent-kaur-15-one (2; and 1α-acetoxy-14β-hydroxy-7α,20-epoxy-ent-kaur-16-en-15-one (3; together with six known diterpenes henryin (4; kamebanin (5; reniformin C (6; kamebacetal A (7; kamebacetal B (8; and oridonin (9. The structures of the isolated compounds were elucidated by means of nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry in conjunction with published data for their analogs, as well as their fragmentation patterns. Compounds 5 and 9 were isolated from Isodon excisoides for the first time. To explore the structure-activity relationships of the isolated compounds, they were tested for their cytotoxic effects against five human cancer cell lines: HCT-116, HepG2, A2780, NCI-H1650, and BGC-823. Most of the isolated compounds showed certain cytotoxic activity against the five cancer cell lines with IC50 values ranging from 1.09–8.53 µM. Among the tested compounds, compound 4 exhibited the strongest cytotoxic activity in the tested cell lines, with IC50 values ranging from 1.31–2.07 µM. Compounds 1, 6, and 7 exhibited selective cytotoxic activity.

Tallinna Inglise Kolledzhi spordihoone : Pärnu mnt. 13/Estonia pst. 10 = Tallinn English College sports building : Pärnu mnt. 13/Estonia pst. 10 / Liina Jänes

Index Scriptorium Estoniae

Jänes, Liina, 1977-

2008-01-01

Arhitektid: Lembit-Kaur Stöör, Margus Maiste, Andrus Kõresaar. Sisearhitektid: Liisi Murula, Raili Paling, Liis Lindvere. Peatöövõtja: Skanska EMV AS. I korruse plaan, 3 värv. välisvaadet, 3 sisevaadet

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

mercury(II)]2 complex · Tarlok S Lobana Amarjeet Singh Mandeep Kaur Alfonso Castineiras · More Details Abstract Fulltext PDF. Reaction of mercury(II) diiodide with triphenyl selenophosphorane-Se (1:1 mole ratio) in acetone followed by ...

Fotonäitus koduta loomade heaks / Indrek Galetin, Kerttu Rakke, Angela Aak ... [jt.

Index Scriptorium Estoniae

Galetin, Indrek

2009-01-01

Rotermani kvartalis 22.05.2009 avatud Indrek Galetini fotonäitus "Amour - Lemmikloomade eri". Kodutute loomade abistamiseks 20.07.2009 oksjonil müüdavate piltide valmimist kommenteerivad fotograaf ja modellid Kerttu Rakke, Angela Aak ja Max Kaur

Terpenoids, flavonoids and other constituents of Eupatorium betonicaeforme (Asteraceae)

Energy Technology Data Exchange (ETDEWEB)

Albuquerque, Maria Rose Jane R.; Pires, Andreza Maria L.; Pessoa, Otilia Deusdenia L.; Silveira, Edilberto R. [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Quimica Organica e Inorganica. Curso de Pos-Graduacao em Quimica Organica]. E-mail: opessoa@ufc.br

2006-01-15

A new acylated kaurene diterpene, characterized as 15{alpha}-decanoyloxy-kaur-16-en-19-oic acid, along with nine known compounds: pentacosanoic acid, 24{alpha}-ethyl-5{alpha}-cholesta-7,22E-dien-3{beta}-ol, 15{alpha}-hydroxy-kaur-16-en-19-oic acid, 8{beta}-angeloyloxy-9{beta},10{beta}-dihydroxy-1-oxogermacra-4E,11(13)dien-12,6{alpha}-olide, 3{beta}-hydroxyeicosan-1,5{beta}-olide, taraxasteryl acetate, 7-Omethylkaempferol, kaempferol, and nepetin were isolated from the flowers of Eupatorium betonicaeforme (Asteraceae). In addition, from the aerial parts were isolated taraxasteryl acetate and {alpha}- and {beta}-amyrin, while the mixture of {beta}-sitosterol and stigmasterol, and 6-acetyl-2,2-dimethylchroman-4-one were isolated from the roots. The structure elucidation of all compounds was performed by spectroscopic analysis and comparison with published data from literature. (author)

Terpenoids, flavonoids and other constituents of Eupatorium betonicaeforme (Asteraceae)

International Nuclear Information System (INIS)

Albuquerque, Maria Rose Jane R.; Pires, Andreza Maria L.; Pessoa, Otilia Deusdenia L.; Silveira, Edilberto R.

2006-01-01

A new acylated kaurene diterpene, characterized as 15α-decanoyloxy-kaur-16-en-19-oic acid, along with nine known compounds: pentacosanoic acid, 24α-ethyl-5α-cholesta-7,22E-dien-3β-ol, 15α-hydroxy-kaur-16-en-19-oic acid, 8β-angeloyloxy-9β,10β-dihydroxy-1-oxogermacra-4E,11(13)dien-12,6α-olide, 3β-hydroxyeicosan-1,5β-olide, taraxasteryl acetate, 7-Omethylkaempferol, kaempferol, and nepetin were isolated from the flowers of Eupatorium betonicaeforme (Asteraceae). In addition, from the aerial parts were isolated taraxasteryl acetate and α- and β-amyrin, while the mixture of β-sitosterol and stigmasterol, and 6-acetyl-2,2-dimethylchroman-4-one were isolated from the roots. The structure elucidation of all compounds was performed by spectroscopic analysis and comparison with published data from literature. (author)

Virumaa noored on filmifestivalil sanitarideks / Maria Uuetoa

Index Scriptorium Estoniae

Uuetoa, Maria

2008-01-01

Pärnu 22. dokumentaal- ja antropoloogiafilmide festivalil töötavad vabatahtlike filmisanitaridena neli Rakvere noormeest : Karl Robert Saaremäe, Kaur Teder, Peeter Tiimus ja Ringo Ramul. Nende ülesanne on filmida kõike, mis Pärnus valesti

Genetic controls on starch amylose content in wheat and rice grains

Indian Academy of Sciences (India)

2014-04-07

Apr 7, 2014 ... cuboid in appearance and smaller than wheat or maize. (figure 3; Kaur et al. 2007). ..... gaps in our knowledge. Due to the hexaploid ...... Makino A 2011 Photosynthesis, grain yield, and nitrogen utilization in rice and wheat.

Taastatud Jaani kiriku interjöörid 21. sajandi kontekstis / Krista Kodres

Index Scriptorium Estoniae

Kodres, Krista, 1957-

2006-01-01

Tartu Jaani kiriku interjööridest. Kunstiajaloolane Kaur Alttoa. Sisekujundajad: Tea Tammelaan, Malle Jürgenson, Krista Lepland. Terrakotaskulptuure on konserveerinud, algul koos sakslastega (Sven Wallasch, keemik Eberhard Wendler), Eve Alttoa. Fassaadiskulptuuride koopiad valmistab Isabel Aaso. Ka Urmo Rausi akendeprojektist

Kultuuriminister Signe Kivi moodustas rahvusvahelise ekspertkomisjoni...

Index Scriptorium Estoniae

2001-01-01

Komisjon, kuhu kuuluvad Maie Raun, Mart Kalm, Kaur Alttoa, Juhani Jaeger Eestist, vitraažikunsti eksperdid Ake Nisbeth Rootsist ja Andreas Dierig Saksamaalt, annab hinnangu Urmo Rausi Tartu Jaani kiriku vitraažiprojektile. Prooviakna ja kavanditega tutvutakse Tartus 17.-21. IX

In vitro plant regeneration in rough lemon (Citrus jambhiri Lush) by ...

African Journals Online (AJOL)

Jane

2011-10-17

Oct 17, 2011 ... H S Rattanpal*1, Gagandeep Kaur2 and Monika Gupta2 ... Seeds were extracted from ripe fruits of rough lemon. ... extract and additional dose of 25 g/l sucrose. ..... important grapefruit cultivar Rio Red (Citrus paradise Macf.).

UNCORRECTED PROOF

Indian Academy of Sciences (India)

Detrimental effect of expression of Bt endotoxin Cry1Ac on in vitro regeneration, in vivo growth and development of tobacco and cotton transgenics. PREETI RAWAT, AMARJEET KUMAR SINGH, KRISHNA RAY, BHUPENDRA CHAUDHARY,. SANJEEV KUMAR, TARU GAUTAM, SHAVETA KANORIA, GURPREET KAUR, ...

Marati maja müük võib olla aasta suurtehing / Kadrin Karner

Index Scriptorium Estoniae

Karner, Kadrin

2008-01-01

Kinnisvarafond Baltic Property Trust ostis Tallinnas Marati hoone. Müüja, Prisma Prindi Kinnisvara juhi Urmas Osila sõnul on tegemist selle aasta suurima tehinguga. Vt. samas: Marati hoone Tartu mnt 63; Baltic Property Trust. Kommenteerivad Kaur-Kaspar Kull ja Ruben Gornischeff

Neutral current cross-section measurement at low Q and high y with ...

Indian Academy of Sciences (India)

2012-11-11

Nov 11, 2012 ... energy, Ee, and polar angle, θe, of the scattered electron [1]. Q2 e = 2Ee Ee ... Prabhdeep Kaur and low-energy-running (LER) samples. ... to the combined detector-level predictions from the Monte Carlo (MC) models. Good.

Ängist kirgastumiseni / Aita Kivi

Index Scriptorium Estoniae

Kivi, Aita, 1954-

2000-01-01

Sisu : Frank McCourt. Jah, on küll; Kaur Kender. Ebanormaalne; Arnon Grunberg. Helesinised esmaspäevad; Melvin Burgess. Saast; Louis de Bernières. Kapten Corelli mandoliin; Jaergen-Frantz Jacobsen. Barbara; Jayne Ann Krentz. Sügavad veed; Enno Tammer. Uppumatu Estonia

Otlitshnõi sportzal / Urmas Oja

Index Scriptorium Estoniae

Oja, Urmas, 1981-2012

2007-01-01

Tallinna Inglise Kolledzhi spordihoonest (Pärnu mnt. 13). Ehituse peatöövõtja: Skanska EMV. Arhitektid: Margus Maiste ja Kaur Stöör, AB KOKO. Ehituse kestus: juuni 2005-aprill 2007. 2 värv. välis- ja 2 sisevaadet

Journal of Biosciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Microstructural abnormalities of uncinate fasciculus as a function of impaired cognition in schizophrenia: A DTI study · SADHANA SINGH KAVITA SINGH RICHA TRIVEDI SATNAM GOYAL PRABHJOT KAUR NAMITA SINGH TRIPTISH BHATIA SMITA N DESHPANDE SUBASH KHUSHU · More Details Abstract Fulltext PDF.

Resonance – Journal of Science Education | Indian Academy of ...

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 17; Issue 5. Transit of Venus: Quantitative Observing with Simple Equipment. N Rathnasree Pritpal Kaur. Classroom Volume 17 Issue 5 May 2012 pp 497-504. Fulltext. Click here to view fulltext PDF. Permanent link:

Tallinna uus sünagoog = The New Tallinn Synagogue / Triin Ojari

Index Scriptorium Estoniae

Ojari, Triin, 1974-

2007-01-01

Arhitektid: KOKO Arhitektid - Andrus Kõresaar (loovjuht), Kaur Stöör, Tõnis Kimmel. Konstruktor: Toomas Tammerik. Sisekujundus: Liis Lindvere, Raili Paling (KOKO Arhitektid). Tellija: Eesti Juudiusu Kogudus. Projekt: 2005-2006, valmis: 2007. II korruse plaan, lõige, 2 välisvaadet, sisevaade

Additional Minor Diterpene Glycosides from Stevia rebaudiana Bertoni

Directory of Open Access Journals (Sweden)

Indra Prakash

2013-10-01

Full Text Available Two additional novel minor diterpene glycosides were isolated from the commercial extract of the leaves of Stevia rebaudiana Bertoni. The structures of the new compounds were identified as 13-{β-D-glucopyranosyl-(1→2-O-[β-D-glucopyranosyl-(1→3-β-D-glucopyranosyl-oxy} ent-kaur-16-en-19-oic acid {β-D-xylopyranosyl-(1→2-O-[β-D-glucopyranosyl-(1→3]-O-β-D-glucupyranosyl-ester} (1, and 13-{β-D-6-deoxy-glucopyranosyl-(1→2-O-[β-D-glucopyranosyl-(1→3-β-D-glucopyranosyl-oxy} ent-kaur-16-en-19-oic acid {β-D-glucopyranosyl-(1→2-O-[β-D-glucopyranosyl-(1→3-β-D-gluco-pyranosyl-ester} (2, on the basis of extensive 1D (1H- and 13C- 2D NMR (COSY, HSQC and HMBC and MS spectroscopic data as well as chemical studies.

Plaadid / Kaur Garshnek, Maris Meiesaar, Tiiu Laks

Index Scriptorium Estoniae

Garšnek, Kaur, 1983-

2008-01-01

Uutest heliplaatidest Holst Singers ja Stephen Layton, Stephen "Rockferry", Queens Of Stone Age "Era Vulgaris Tour Edition", "Crystal Castles", Operator Please "Yes Yes Vindictive", Morcheeba "Dive Deep"

Kolmikpointi reklaam häirib vaimulikke / Enn Uus

Index Scriptorium Estoniae

Uus, Enn

2001-01-01

Radiolinja Kolmikpointi mobiiltelefoni sooduspaketi reklaam vannist vastu vaatava neiu ja kahe noormehega häirib kirikuringkondi vaimuliku ametiriietuse kasutamise ja perekonnaväärtuste labastamise tõttu. Kampaania autor on reklaamibüroo Zoom. Reklaamibüroo töötaja Kaur Hansoni kommentaar

Korsten : tellimata tellised = Chimney : an outside job / Andres Aule

Index Scriptorium Estoniae

Aule, Andres

2012-01-01

Aap Kaur Suvi kavandatud Tallinna linnainstallatsioonide festivali "LIFT11" installatsioonist "Korsten", mis pidi seisnema Tauno Kangro skulptuuri "Lõbus korstnapühkija" ümber ajutise telliskorstna ehitamises. Lift11 jättis selle installatsiooni ära, kuid ootamatult sai "Korsten" kodanikualgatusena 8. IX 2011 teoks

2623-IJBCS-Article-Gadji Alahou André

African Journals Online (AJOL)

hp

1. Alahou André Gabazé GADJI1,2*, Ossey Bernard YAPO1, Kouabenan ABO2,. Ladji MEITE1, Agnès Eude Yves GNAGNE1, Satinder Kaur BRAR 3 et. Rajeshwar Dayal TYAGI4. 1Laboratoire des Sciences de l'Environnement (LSE), Unité de ...

Iga hetk peab teadma, mis ettevõttes toimub / Imbi Ernits-Kaljuste

Index Scriptorium Estoniae

Ernits-Kaljuste, Imbi, 1963-

2008-01-01

Tulemusjuhtimise juurutamisest maailma juhtivas bio-innovatsiooniga tegelevas tootmisettevõttes Novozymes. Skeem: Maailma juhtiva ensüümide tootja Novozymesi kvaliteedisüsteem jälgib pidevalt üheksat näidikut. Lisa: Novozymesi tulemusjuhtimissüsteem. Vt. samas: Kaur Kivirähk. Kvaliteedisüsteemid tolmuvad riiulil

African Journal of Biotechnology - Vol 11, No 83 (2012)

African Journals Online (AJOL)

Genetic diversity among selected genotypes of almond Prunus dulcis Miller D.A. Webb assessed by random amplified polymorphic DNA (RAPD) markers · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Deepka Sharma, Rajinder Kaur, Krishan Kumar, SatyaVrat ...

Effects of carbon and nitrogen sources on the induction and ...

African Journals Online (AJOL)

Effects of carbon and nitrogen sources on the induction and repression of chitinase enzyme from Beauveria bassiana isolates. Priyanka Dhar, Gurvinder Kaur. Abstract. Beauveria bassiana a natural soil borne insect pathogen is being used effectively these days in integrated pest management system. Foliar application of ...

D D Bansal

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education. D D Bansal. Articles written in Resonance – Journal of Science Education. Volume 8 Issue 12 December 2003 pp 92-93 Research News. New Insights into Obesity · D D Bansal Ravneet Kaur Boparai · More Details Fulltext PDF ...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences. N Kaur. Articles written in Journal of Chemical Sciences. Volume 125 Issue 3 May 2013 pp 555-560. Application of chalcones in heterocycles synthesis: Synthesis of 2-(isoxazolo, pyrazolo and pyrimido) substituted analogues of 1,4-benzodiazepin-5-carboxamides linked ...

Trachylobane and kaurane diterpenes from Croton floribundus spreng

Energy Technology Data Exchange (ETDEWEB)

Uchoa, Paula Karina S.; Silva Junior, Jose Nunes da; Silveira, Edilberto Rocha; Lima, Mary Anne S., E-mail: mary@dqoi.ufc.br [Departamento de Quimica Organica e Inorganica, Centro de Ciencias, Universidade Federal do Ceara, Fortaleza, CE (Brazil); Braz-Filho, Raimundo [Laboratorio de Ciencias Quimicas, Centro de Ciencias Tecnologicas, Universidade Estadual do Norte Fluminense, Campo dos Goytacazes, RJ (Brazil); Costa-Lotufo, Leticia Veras; Araujo, Ana Jersia; Moraes, Manoel Odorico de; Pessoa, Claudia do O [Departamento de Farmacologia e Fisiologia, Centro de Ciencias da Saude, Universidade Federal do Ceara, Fortaleza, CE (Brazil)

2013-09-01

A new trachylobane diterpene ent-trachyloban-18,19-diol (1) was isolated from root bark of Croton floribundus, along with known diterpenes ent-trachyloban-19-oic acid (2), 15{beta}-hydroxy-ent-trachyloban-19-oic acid (3), ent-trachyloban-19-ol (4), ent-kaur-16-en-19-oic acid (5), ent-kaur-16-ene-6{alpha},19-diol (6) and ent-16{alpha}-hydroxykaur-11-en-19-oic acid (7). ent-trachyloban-18,19-diol (1) was submitted to derivatization reactions affording four new compounds (8-11). Cytotoxic activity of diterpenes 1, 3, 4, 7-11 against three human cancer cell lines was evaluated. No compounds showed cytotoxic potential with IC{sub 50} values greater than 25 {mu}g/mL. Compound 6 was evaluated against five human cancer cell lines, showing moderate effect against three cancer cell lines, MDA-MB-435, HCT-8 and HCT-116, with IC{sub 50} values of 14.32, 13.47 and 12.1 {mu}g/mL, respectively. (author)

Trachylobane and kaurane diterpenes from Croton floribundus spreng

International Nuclear Information System (INIS)

Uchôa, Paula Karina S.; Silva Junior, José Nunes da; Silveira, Edilberto Rocha; Lima, Mary Anne S.; Braz-Filho, Raimundo; Costa-Lotufo, Letícia Veras; Araújo, Ana Jérsia; Moraes, Manoel Odorico de; Pessoa, Claudia do Ó

2013-01-01

A new trachylobane diterpene ent-trachyloban-18,19-diol (1) was isolated from root bark of Croton floribundus, along with known diterpenes ent-trachyloban-19-oic acid (2), 15β-hydroxy-ent-trachyloban-19-oic acid (3), ent-trachyloban-19-ol (4), ent-kaur-16-en-19-oic acid (5), ent-kaur-16-ene-6α,19-diol (6) and ent-16α-hydroxykaur-11-en-19-oic acid (7). ent-trachyloban-18,19-diol (1) was submitted to derivatization reactions affording four new compounds (8-11). Cytotoxic activity of diterpenes 1, 3, 4, 7-11 against three human cancer cell lines was evaluated. No compounds showed cytotoxic potential with IC 50 values greater than 25 μg/mL. Compound 6 was evaluated against five human cancer cell lines, showing moderate effect against three cancer cell lines, MDA-MB-435, HCT-8 and HCT-116, with IC 50 values of 14.32, 13.47 and 12.1 μg/mL, respectively. (author)

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences; Volume 125; Issue 3. Application of chalcones in heterocycles synthesis: Synthesis of 2-(isoxazolo, pyrazolo and pyrimido) substituted analogues of 1,4-benzodiazepin-5-carboxamides linked through an oxyphenyl bridge. N Kaur D Kishore. Volume 125 Issue 3 May 2013 pp ...

Some extensions and applications of Eisenstein Irreducibility ...

Indian Academy of Sciences (India)

Page 1. Some extensions and applications of Eisenstein Irreducibility. Criterion. Sudesh Kaur Khanduja ..... Beginning from the individual theorems, I grew ac- customed to delve more deeply into their relationships and to grasp whole theories as a single entity. That is how I conceived the idea of mathematical beauty .

Sisekaitseakadeemia peahoone võistlus / Ülar Mark

Index Scriptorium Estoniae

Mark, Ülar, 1968-

2016-01-01

Artiklis on antud ülevaade võistlusele esitatud töödest. Esimese preemia sai töö "Faalanks" (autorid: Illimar Truverk, Janar Toomesso, Katrin Vannas, Sander Paljak, Kristjan Lind, Hannelore Kääramees, Kaur Käärma, Siim Tiigimägi, Edgar Kaare, Terje Ong ja Liina Einla)

Application of chalcones in heterocycles synthesis: Synthesis of 2 ...

Indian Academy of Sciences (India)

556. N Kaur and D Kishore gel G plates in the solvent system benzene–methanol ... in ice water (100mL) and stirred for 30min until the reaction mixture reached to ... acetate (0.033mol) in glacial acetic acid was refluxed for 5h. The reaction ...

Journal of Biosciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Biosciences. PRABHJOT KAUR. Articles written in Journal of Biosciences. Volume 40 Issue 2 June 2015 pp 355-364 Articles. Functional and structural abnormalities associated with empathy in patients with schizophrenia: An fMRI and VBM study · Sadhana Singh Shilpi Modi Satnam Goyal ...

Lembit-Kaur Stöör teeb isevärki maju / Lembit-Kaur Stöör ; interv. Epp Lankots

Index Scriptorium Estoniae

Stöör, Lembit-Kaur, 1976-

2008-01-01

Büroos KOKO Arhitektid töötav arhitekt L.-K. Stöör A. Kõresaare ja R. Kotovi poolt asutatud büroost, oma eeskujudest arhitektuuris, Tallinna Inglise Kolledzhi juurdeehitusest (koos M. Maistega, sisearhitektid: L. Lindvere, L. Murula, R. Paling), konstruktor T. Tammerik), 2007. a. Kultuurkapitali arhitektuuri sihtkapitali objektibreemia võitnud Tallinna sünagoogist (koos Tõnis Kimmeliga, sisearhitektid: L. Lindvere, R. Paling), Kuldala elamurajoonist (koos M. Maistega)

Research Paper ISSN 0189-6016©2008

African Journals Online (AJOL)

AJTCAM

identified as (ent)-kaur-16-en-19-oic acid (KA) and (ent)-pimara-8, 15-dien-19-oic acid (PA). Both compounds were significantly effective regarding analgesics, hypothermia, duration of pentobarbital-induced anesthesia, and depression of locomotor activity enhanced by methamphetamine at doses of 300 mg/kg (KA) and ...

Erythrocyte Osmotic Fragility and Excitability Score in Rabbit fed ...

African Journals Online (AJOL)

olayemitoyin

protect cells against oxidative stress in rats (Wang et al., 2000) and ... method, total red blood cell (RBC) count, total leukocyte (WBC) count .... maturative stages of the erythroblast (pluripotent stem cells) involved in cell formation (Kaur and. Kapoor, 2005). ... effect of zinc on chlorpyrifos- induced erythrocyte fragility in wistar ...

P N Kotru

Indian Academy of Sciences (India)

Volume 33 Issue 4 August 2010 pp 377-382 Electrical Properties. Dielectric and thermal studies on gel grown strontium tartrate pentahydrate crystals ... High resolution X-ray diffraction studies on unirradiated and irradiated strontium hexaferrite crystals · Balwinder Kaur Monita Bhat F Licci Ravi Kumar K K Bamzai P N Kotru.

Eesti kirjandussuve nägu / Barbi Pilvre

Index Scriptorium Estoniae

Pilvre, Barbi, 1963-

2000-01-01

Raud, Rein. Pisiasjad, mis omavd tähtsust. Tln. : Tuum, 2000; Kender, Kaur. Ebanormaalne. Tln. : Eks, 2000; Õunapuu, Ervin. Väike palveraamat. Tln. : Umara, 2000 ; Hellerma, Kärt. Kassandra. Tln. : Hotger, 2000 ; Park, Eeva. Pääse karussellile. Tln. ; Huma, 2000 ; Tammann, Tiina. Tihe udu Tallinnas. Tln. : Perioodika, 2000

Eesti lühifilm sai erootikapreemia

Index Scriptorium Estoniae

2005-01-01

Itaalias Montecatini lühifilmide festivalil sai kategoorias "Eros in short films" parima filmi auhinna lühimängufilm "Ring" : stsenaristid : Andrus Tuisk, Urmas Lennuk, Kaur Kender : režissöör Andrus Tuisk : osades Lembit Ulfsak, Merle Palmiste ja Karl Annus : Tuisk Film - Parunid ja Vonid 2004

Milline on ilus maja? / Sulev Oll

Index Scriptorium Estoniae

Oll, Sulev, 1964-

2008-01-01

Ilusatest majadest ja arhitektuurikonkursside võiduprojektidest. Konkursist "Brick Award". Tallinna sünagoog valiti rahvusvahelise tellisarhitektuuri aastaraamatusse "brick'08" (arhitektid Lembit-Kaur Stöör, Andrus Kõresaar, Tõnis Kimmel arhitektuuribüroost KOKO Arhitektid). Loetletud konkursi "Aasta betoonehitis" võitjad läbi aegade. Kommenteerivad Margit Mutso, Emil Urbel

Optical, mechanical and TEM assessment of titania-doped Bi2V1 ...

Indian Academy of Sciences (India)

Author Affiliations. Gurbinder Kaur1 Gary Pickrell1 Vishal Kumar1 2 Om Prakash Pandey3 Kulvir Singh3 Daniel Homa1. Department of Material Science and Engineering, Holden Hall, Virginia Tech, Blacksburg, Virginia 24060, USA; Sri Guru Granth Sahib World University, Fategarh Sahib 140 406, India; School of Physics ...

Sadhana | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Sadhana. G DEEP. Articles written in Sadhana. Volume 43 Issue 2 February 2018 pp 20. Biomedical image retrieval using microscopic configuration with local structural information · G DEEP L KAUR S GUPTA · More Details Abstract Fulltext PDF. This paper focusses on the use of microscopic configuration ...

Photoluminescence, trap states and thermoluminescence decay ...

Indian Academy of Sciences (India)

Administrator

Photoluminescence, trap states and thermoluminescence decay process study of Ca2MgSi2O7 : Eu. 2+. , Dy. 3+ phosphor. RAVI SHRIVASTAVA*, JAGJEET KAUR, VIKAS DUBEY and BEENA JAYKUMAR. Govt. VYT PG Autonomous College, Durg 491 001, (C.G.) India. MS received 9 July 2013; revised 5 December 2013.

Metro Plaza za fasadom Rotermanna / Viktoria Jürmann

Index Scriptorium Estoniae

Jürmann, Viktoria

2008-01-01

Pandi nurgakivi Tallinnas Viru väljaku äärde rajatavale büroohoonele Metro Plaza. Säilitatakse vana fassaad, mille tõttu kujuneb hoone Viru väljaku ja Mere puiestee poolsel küljel kaetud galerii jalakäijatele. Projekteerisid Raivo Kotov ja Kaur Stöör

Three-dimensional Morphology and X-ray Scattering Structure of ...

Indian Academy of Sciences (India)

Aqueous tert-Butanol Mixtures: A Molecular Dynamics Study. SUPREET KAUR and ... In addition to this, we also observe dimers and small clusters of water molecules in the TBA-rich regime. ... formed MC18 and subsequently MD19,20 simulation studies for ... such analysis on water-TBA structure has not been reported in ...

Journal of Biosciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Biosciences. Anil K Gupta. Articles written in Journal of Biosciences. Volume 27 Issue 7 December 2002 pp 703-714 Review Article. Applications of inulin and oligofructose in health and nutrition · Narinder Kaur Anil K Gupta · More Details Abstract Fulltext PDF. Inulin and oligofructose belong to a ...

Euroopa tellisepreemia 2006 / Triin Ojari

Index Scriptorium Estoniae

Ojari, Triin, 1974-

2006-01-01

Viinis toimunud Euroopa tellisarhitektuuri auhindade Brick'06 kätteandmisel märgiti ära Tartu Jaani kiriku taastamine (arhitekt Udo Tiirmaa, kunstiajaloolane Kaur Alttoa). Esimene koht: Ungari Pecsi linna Barbakani väljaku elu- ja ärikompleks (arhitektid Ferenc Csagoly, Ferenc Keller). Teine koht: kiriku rekonstruktsioon raamatukoguks Madridis (arhitekt Jose Ignacio Rodriguez)

The Improved Estimation of Ratio of Two Population Proportions

Science.gov (United States)

Solanki, Ramkrishna S.; Singh, Housila P.

2016-01-01

In this article, first we obtained the correct mean square error expression of Gupta and Shabbir's linear weighted estimator of the ratio of two population proportions. Later we suggested the general class of ratio estimators of two population proportions. The usual ratio estimator, Wynn-type estimator, Singh, Singh, and Kaur difference-type…

Plaadid / Kaur Garshnek, Mart Niineste, Tui Hirv...[jt.

Index Scriptorium Estoniae

2008-01-01

Uutest heliplaatidest Tuule Kann/Jaak Sooäär "Õhtu ilu", The Mars Volta "The Bedlam In Goliath", Eva Dahlgren "Petroleum Och Tang", Lenny Kravitz "It's Time For A Love revolution", "Flyleaf ", New Project "Ultraviolent Light"

Tallinna rannaala üldplaneering / Kaur Lass, Merje Muiso

Index Scriptorium Estoniae

Lass, Kaur, 1973-

2004-01-01

Paljassaare ja Russalka vahelise rannaala üldplaneeringu kehtestamist Tallinna Linnavalitsuse poolt on oodata 2004. a. kevadel. Vaatluse all: kesklinn, tööstuspiirkond, Paljassaare poolsaar, mere ja linna side, linnaehituslike reeglite seadmine, detailplaneeringute koostamise reeglid, arhitektuurikonkursid, sadamad, infrastruktuur

Plaadid / Kaur Garshnek, Ave Randviir, Priit Pruul...[jt.

Index Scriptorium Estoniae

2007-01-01

Uutest heliplaatidest Jaak Sooäär, Raul Vaigla, Tanel Ruben "No99 Jazzklubis", Black Strobe "Burn Your Own Church", The Quantic Soul Orchestra "Tropidelico", Uni "Kosmikud II", Bugge Wesseltoft "IM", Gabrielle "Always"

Sokoto Journal of Veterinary Sciences - Vol 11, No 1 (2013)

African Journals Online (AJOL)

Prevalence of parasitic infections of stray cats in Jammu, India · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. S Borkataki, R Katoch, P Goswami, R Godara, JK Khajuria, A Yadav, R Kaur, 1-6. http://dx.doi.org/10.4314/sokjvs.v11i1.1 ...

Metro Plaza tõi Viru väljakule LED-valguse hõõguva tuledemängu / Maris Meiessaar

Index Scriptorium Estoniae

Meiessaar, Maris

2009-01-01

2009. a. alguses Tallinnas Viru väljak 2 valmivast ärihoonest ja selle klaasfassaadide valgustusest. Ärihoone seisab 19. saj. ehitatud maja muinsuskaitse all oleva fassaadi taga. Autorid: büroo KOKO Arhitektid arhitektid Raivo Kotov ja Lembit-Kaur Stöör ning sisearhitektid Liis Lindvere ja Raili Paling. Ehitaja: Facio Ehitus

Pramana – Journal of Physics | Indian Academy of Sciences

Indian Academy of Sciences (India)

... preformed cluster model (PCM). pp 623-638 Research Articles. Design and fabrication of a time-of-flight spectrometer for studies of multiple ionization of gases by charged particle impact .... pp 703-711 Brief Reports. Current correlation functions of ideal Fermi gas at finite temperature · R P Kaur K Tankeshwar K N Pathak.

Resonance – Journal of Science Education | News

Indian Academy of Sciences (India)

What is Transit? B S Shylaja · More Details Fulltext PDF. pp 493-496 Classroom. On a Definite Integral of the Fractional Part Function · Koundinya Vajjha · More Details Fulltext PDF. pp 497-504 Classroom. Transit of Venus: Quantitative Observing with Simple Equipment · N Rathnasree Pritpal Kaur · More Details Fulltext ...

Soomes ilmusid eesti raamatud

Index Scriptorium Estoniae

2004-01-01

Mehis Heinsaare "Härra Pauli kroonikad" ("Herra Paulin aikakirja"), tõlkinud Mika Keränen ; "Tallinnasta pois", eesti groteskse novelli antoloogia, autorid Olavi Ruitlane, Jüri Ehlvest, Aapo Ilves, Andrus Kivirähk, Kerttu Rakke, Peeter Sauter, Mehis Heinsaar, Matt Barker, Eeva Park, Kaur Kender, Veiko Märka, Urmas Vadi ja Ervin Õunapuu

Fulltext PDF

Indian Academy of Sciences (India)

92 New Insights into Obesity o 0 Bansal and Ravneet Kaur Boparai. BOOK REVIEWS. 94 How we Invented the Airplane. C 5 Yogananda. Front Cover. Wright Brothers first flight. •••• J . .... 1. 08 .......... -- (Credit: Courtesy of Special Collections and Archives,. Wright State University). Back Cover. (Colour scheme for cover by ...

Effect-directed analysis via hyphenated high-performance thin-layer chromatography for bioanalytical profiling of sunflower leaves.

Science.gov (United States)

Móricz, Ágnes M; Ott, Péter G; Yüce, Imanuel; Darcsi, András; Béni, Szabolcs; Morlock, Gertrud E

2018-01-19

High-performance thin-layer chromatography (HPTLC) coupled with effect-directed analysis was used for non-targeted screening of sunflower leaf extract for components exhibiting antioxidant, antibacterial and/or cholinesterase enzyme inhibitory effects. The active compounds were characterized by HPTLC-electrospray ionization-high resolution mass spectrometry (ESI-HRMS) and HPTLC-Direct Analysis in Real Time (DART)-MS/MS. The latter ambient ionization technique (less soft than ESI) resulted in oxidation and fragmentation products and characteristic fragment ions. NMR spectroscopy after targeted isolation via preparative normal phase flash chromatography and semi-preparative reversed phase high-performance liquid chromatography supported the identification of two diterpenes to be (-)-kaur-16-en-19-oic acid and 15-α-angeloyloxy-ent-kaur-16-en-19-oic acid. Both compounds found to be multi-potent as they inhibited acetylcholinesterase and butyrylcholinesterase and showed antibacterial effects against Gram-positive Bacillus subtilis and Gram-negative Aliivibrio fischeri bacteria. Kaurenoic acid was also active against the Gram-negative pepper pathogenic Xanthomonas euvesicatoria bacteria. Copyright © 2017 Elsevier B.V. All rights reserved.

Short outlines of books by Estonian authors / Rutt Hinrikus, Janika Kronberg

Index Scriptorium Estoniae

Hinrikus, Rutt, 1946-

2001-01-01

Mari Vallisoo. Ainsuse olevik; Andrus Kivirähk. Rehepapp; Toomas Vint. Elamise sulnis õudus; Andreas Oplatka. Lennart Meri - Eestile elatud elu; Mari Saat. Sinikõrguste tuultes; Eeva Park. Pääse karussellile; Hando Runnel. Mõistatused; Jaan Kaplinski. Kirjutatud; Contra [Konnula, Margus]. Suusamütsi tutt; Triin Soomets. Soon; Ervin Õunapuu. Surmaminejad lasevad tervitada; Kaur Kender. Ebanormaalne

Diterpenoids and phenolics from pseudopanax simplex

Directory of Open Access Journals (Sweden)

JOHN W. VAN KLINK

2006-02-01

Full Text Available An ethanolic extract of Pseudopanax simplex yielded kaempferol-3,7-di-O-rhamnopyranoside, chlorogenic acid, maltol glucoside, ent-kaur-16-en-18-acid, and 4R,5S,9R,10S,13S-ent-pimara-7,15-dien-19-oic acid. Full NMR data for the last compound are reported for the first time.

Diterpenoids from Isodon parvifolius

Directory of Open Access Journals (Sweden)

Libin Yang

2015-06-01

Full Text Available A new ent-kaurane diterpenoid, 2 β , 3 β , 6 β , 11 β -tetraacetoxy -ent -kaur-16 β - methy-15-one (1, along with three kown diterpenoids, hebeirubescensin L (2, rabescensin C (3, and trichokaurin (4 were isolated from the leaves of Isodon parvifolius. Their structures were elucidated on the basis of spectroscopic methods and literatures.

Pramana – Journal of Physics | Indian Academy of Sciences

Indian Academy of Sciences (India)

Articles written in Pramana – Journal of Physics. Volume 58 Issue 5-6 May-June 2002 pp 799-802 Superconductivity. Microwave absorption studies of MgB2 superconductor · M K Bhide R M Kadam M D Sastry Ajay Singh Shashwati Sen Manmeet Kaur D K Aswal S K Gupta V C Sahni · More Details Abstract Fulltext PDF.

Optical, mechanical and TEM assessment of titania-doped Bi2V1 ...

Indian Academy of Sciences (India)

2016-08-26

Aug 26, 2016 ... Home; Journals; Bulletin of Materials Science; Volume 37; Issue 7. Optical, mechanical and TEM assessment of titania-doped Bi2V1−TiO5.5−δ bismuth vanadate oxides. Gurbinder Kaur Gary Pickrell Vishal Kumar Om Prakash Pandey Kulvir Singh Daniel Homa. Volume 37 Issue 7 December 2014 pp ...

Milline on meie vaimu seis / Mati Sirkel

Index Scriptorium Estoniae

Sirkel, Mati

2002-01-01

Eesti kirjanike ja kirjanduse kajastamisest meedias. Vastukajad: Raudnask, Valve. Mula nagu muda // Postimees (2002) 22. okt., lk. 12 (Kirjad); Kender, Kaur. Tüütu ja tülikas armastus // Postimees (2002) 28. okt., lk. 13 (Arvamus); Kadastik, Mart. Kenderi seadus - avameelselt armastusest // Postimees (2002) 30. okt., lk. 13; Berg, Maimu. Geniaalsuse asemel nahaalsus //Postimees (2002) 2. nov., lk. 9

On teil mõnda seksiga raamatut kah? / Tauno Vahter

Index Scriptorium Estoniae

Vahter, Tauno

2001-01-01

Arvustus: Bukowski, Charles. Naised / inglise k. tlk. Peeter Sauter. Tallinn : Hotger, 2001 ; Bukowski, Charles. Postkontor / inglise k. tlk. Kaur Kender. Tallinn : Hotger, 2001 ; Jerofejev, Venedikt. Moskva-Petushki / vene k. tlk. Ott Arder. 2. tr. Tallinn Tänapäev, 2001 ; Jerofejev, Venedikt. Psühhopaadi märkmed / vene k. tlk. Igor Kurve. Tallinn : Tänapäev, 2001

[Literaturwerkstatt Berlin`i loodud ja koordineeritud rahvusvaheline kaasaegse luule portaal

Index Scriptorium Estoniae

2014-01-01

42 riigi kirjandusorganisatsioonide ühistöö varal täienevas kaasaegse luule portaalis http://www.lyrikline.org saab kuulata ja lugeda 1000 luuletaja loomingut ja neist 11 on eesti autorid: Elo Viiding, Maarja Kangro, Jürgen Rooste, Birk Rohelend, Kaur Riismaa, Indrek Mesikepp, Maria Lee, Asko Künnap, Hasso Krull, Veronika Kivisilla ja Igor Kotjuh

Pramana – Journal of Physics | Indian Academy of Sciences

Indian Academy of Sciences (India)

When observed spectrum of a diatomic molecule is expressed in terms of the Dunham coefficients 00, 10, 20, 01, and 11 only, dissociation energy of the molecule is given by 00 + 10 2 /(-420). Kaur and Mahajan [1] have used the Dunham coefficients 10, 20, 01, and 11, for 15 vibrational states of 12 ...

Pramana – Journal of Physics | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Pramana – Journal of Physics. Ajay Singh. Articles written in Pramana – Journal of Physics. Volume 58 Issue 5-6 May-June 2002 pp 799-802 Superconductivity. Microwave absorption studies of MgB2 superconductor · M K Bhide R M Kadam M D Sastry Ajay Singh Shashwati Sen Manmeet Kaur D K Aswal ...

Network chemistry, network toxicology, network informatics, and network behavioristics: A scientific outline

OpenAIRE

WenJun Zhang

2016-01-01

In present study, I proposed some new sciences: network chemistry, network toxicology, network informatics, and network behavioristics. The aims, scope and scientific foundation of these sciences are outlined.

Tallinna Inglise kolledzhi spordihoone = The Tallinn English College's sports building

Index Scriptorium Estoniae

2008-01-01

Tallinna Inglise kolledzhi spordihoone (Estonia pst. 10, Tallinn) sisekujundusest. Arhitektid: Lembit-Kaur Stöör ja Margus Maiste (KOKO Arhitektid), sisearhitektid: Liisi Murula (Mari OÜ), Liis Lindvere ja Raili Paling, ornamentika: Martin Lazarev (KOKO Arhitektid). Sisearhitektidest, nende tähtsamad tööd. 5 korruse plaani, 2 värv. välis- ja 11 sisevaadet, fotod sisearhitektidest

Short outlines of books by Estonian authors : [annotations] / Rutt Hinrikus, Janika Kronberg

Index Scriptorium Estoniae

Hinrikus, Rutt, 1946-

1999-01-01

Ehin, Andres. Seljatas sada meest; Ilmet, Peep. Tuuldunud luule; Kaplinski, Jaan. Öölinnud. Öömõtted; Kender, Kaur. Iseseisvuspäev; Kesküla, Kalev. Vabariigi laulud; Luik, Viivi. Maa taevas; Nõu, Helga. Hundi silmas; Raun, Mait. Wake up; Remsu, Olev. Haapsalu tragöödia; Sauter, Peeter. Kogu moos; Undusk, Jaan. Maagiline müstiline keel; Vint, Toomas. Kunstnikuromaan

Ringiratast meie vabariigi pealinnas / Jan Kaus

Index Scriptorium Estoniae

Kaus, Jan, 1971-

2004-01-01

Esilinastus mängufilm "Täna öösel me ei maga" : stsenaristid Kristian Taska, Jaan Tätte : režissöör Ilmar Taska : operaator Istvan Borbas : produtsent Kristian Taska : peaosades Carmen Kass, Peter Franzen; Maria Avdjushko, Priit Võigemast : Taska Productions. Esilinastus 4. märts 2004. Lisatud Jaan Tätte, Riina Rõõmuse ja Kaur Kenderi kommentaarid.

Bum stroitelstva zdanii posolstva / Urmas Oja

Index Scriptorium Estoniae

Oja, Urmas, 1981-2012

2008-01-01

Pekingi (võidutöö "Tetris" autorid: Andres Põime, Lauri Vaimel, Liisa Põime) ja Riia (võidutöö "Teele" autorid: Lembit-Kaur Stöör, Ülo-Tarmo Stöör, Heidi Urb) Eesti saatkonnahoonete arhitektuurivõistlustest, võidu- ja premeeritud töödest. Eesti virtuaalsest saatkonnahoonest Second Life'is (arhitekt Scope Cleaver, disainer Miko Omegamu, skulptor Seifert Surface)

Saatkonnahoonete buum / Urmas Oja

Index Scriptorium Estoniae

Oja, Urmas, 1981-2012

2008-01-01

Pekingi (võidutöö "Tetris" autorid: Andres Põime, Lauri Vaimel, Liisa Põime) ja Riia (võidutöö "Teele" autorid: Lembit-Kaur Stöör, Ülo-Tarmo Stöör, Heidi Urb) Eesti saatkonnahoonete arhitektuurivõistlustest, võidu- ja premeeritud töödest. Eesti virtuaalsest saatkonnahoonest Second Life'is (arhitekt Scope Cleaver, disainer Miko Omegamu, skulptor Seifert Surface)

Eesti läheb Riia saatkonna ehitusega teisele katsele / Eda Post

Index Scriptorium Estoniae

Post, Eda, 1983-

2008-01-01

Riia Eesti suursaatkonnahoone arhitektuurikonkursist. Esikoha pälvisid Lembit-Kaur Stöör, Ülo-Tarmo Stöör ja Heidi Urb (võistlustöö "Teele"), teise koha saavutasid Emil Urbel, Andrus Mark, Ott Hirvesoo ja Peeter Veimer ("Horta"), kolmanda koha Juris Mitenbergs, Peteris Suprins, Zane Krumina, Uldis Tucs, Edgars Gribusts ja Edijs Kravalis ("White Cube.ee)

Percolation of interdependent network of networks

International Nuclear Information System (INIS)

Havlin, Shlomo; Stanley, H. Eugene; Bashan, Amir; Gao, Jianxi; Kenett, Dror Y.

2015-01-01

Complex networks appear in almost every aspect of science and technology. Previous work in network theory has focused primarily on analyzing single networks that do not interact with other networks, despite the fact that many real-world networks interact with and depend on each other. Very recently an analytical framework for studying the percolation properties of interacting networks has been introduced. Here we review the analytical framework and the results for percolation laws for a Network Of Networks (NONs) formed by n interdependent random networks. The percolation properties of a network of networks differ greatly from those of single isolated networks. In particular, because the constituent networks of a NON are connected by node dependencies, a NON is subject to cascading failure. When there is strong interdependent coupling between networks, the percolation transition is discontinuous (first-order) phase transition, unlike the well-known continuous second-order transition in single isolated networks. Moreover, although networks with broader degree distributions, e.g., scale-free networks, are more robust when analyzed as single networks, they become more vulnerable in a NON. We also review the effect of space embedding on network vulnerability. It is shown that for spatially embedded networks any finite fraction of dependency nodes will lead to abrupt transition

[Social networks in drinking behaviors among Japanese: support network, drinking network, and intervening network].

Science.gov (United States)

Yoshihara, Chika; Shimizu, Shinji

2005-10-01

The national representative sample was analyzed to examine the relationship between respondents' drinking practice and the social network which was constructed of three different types of network: support network, drinking network, and intervening network. Non-parametric statistical analysis was conducted with chi square method and ANOVA analysis, due to the risk of small samples in some basic tabulation cells. The main results are as follows: (1) In the support network of workplace associates, moderate drinkers enjoyed much more sociable support care than both nondrinkers and hard drinkers, which might suggest a similar effect as the French paradox. Meanwhile in the familial and kinship network, the more intervening care support was provided, the harder respondents' drinking practice. (2) The drinking network among Japanese people for both sexes is likely to be convergent upon certain types of network categories and not decentralized in various categories. This might reflect of the drinking culture of Japan, which permits people to drink everyday as a practice, especially male drinkers. Subsequently, solitary drinking is not optional for female drinkers. (3) Intervening network analysis showed that the harder the respondents' drinking practices, the more frequently their drinking behaviors were checked in almost all the categories of network. A rather complicated gender double-standard was found in the network of hard drinkers with their friends, particularly for female drinkers. Medical professionals played a similar intervening role for men as family and kinship networks but to a less degree than friends for females. The social network is considerably associated with respondents' drinking, providing both sociability for moderate drinkers and intervention for hard drinkers, depending on network categories. To minimize the risk of hard drinking and advance self-healthy drinking there should be more research development on drinking practice and the social network.

Vulnerability of network of networks

Science.gov (United States)

Havlin, S.; Kenett, D. Y.; Bashan, A.; Gao, J.; Stanley, H. E.

2014-10-01

Our dependence on networks - be they infrastructure, economic, social or others - leaves us prone to crises caused by the vulnerabilities of these networks. There is a great need to develop new methods to protect infrastructure networks and prevent cascade of failures (especially in cases of coupled networks). Terrorist attacks on transportation networks have traumatized modern societies. With a single blast, it has become possible to paralyze airline traffic, electric power supply, ground transportation or Internet communication. How, and at which cost can one restructure the network such that it will become more robust against malicious attacks? The gradual increase in attacks on the networks society depends on - Internet, mobile phone, transportation, air travel, banking, etc. - emphasize the need to develop new strategies to protect and defend these crucial networks of communication and infrastructure networks. One example is the threat of liquid explosives a few years ago, which completely shut down air travel for days, and has created extreme changes in regulations. Such threats and dangers warrant the need for new tools and strategies to defend critical infrastructure. In this paper we review recent advances in the theoretical understanding of the vulnerabilities of interdependent networks with and without spatial embedding, attack strategies and their affect on such networks of networks as well as recently developed strategies to optimize and repair failures caused by such attacks.

Networks of networks – An introduction

International Nuclear Information System (INIS)

Kenett, Dror Y.; Perc, Matjaž; Boccaletti, Stefano

2015-01-01

Graphical abstract: Interdependent network reciprocity. Only those blue cooperative domains that are initially present on both networks survive. Abstract: This is an introduction to the special issue titled “Networks of networks” that is in the making at Chaos, Solitons & Fractals. Recent research and reviews attest to the fact that networks of networks are the next frontier in network science [1–7]. Not only are interactions limited and thus inadequately described by well-mixed models, it is also a fact that the networks that should be an integral part of such models are often interconnected, thus making the processes that are unfolding on them interdependent. From the World economy and transportation systems to social media, it is clear that processes taking place in one network might significantly affect what is happening in many other networks. Within an interdependent system, each type of interaction has a certain relevance and meaning, so that treating all the links identically inevitably leads to information loss. Networks of networks, interdependent networks, or multilayer networks are therefore a much better and realistic description of such systems, and this Special Issue is devoted to their structure, dynamics and evolution, as well as to the study of emergent properties in multi-layered systems in general. Topics of interest include but are not limited to the spread of epidemics and information, percolation, diffusion, synchronization, collective behavior, and evolutionary games on networks of networks. Interdisciplinary work on all aspects of networks of networks, regardless of background and motivation, is very welcome.

Short outlines of books by Estonian authors : [annotations] / Rutt Hinrikus, Janika Kronberg

Index Scriptorium Estoniae

Hinrikus, Rutt, 1946-

2000-01-01

Kaur Kender. Yuppiejumal; Hiram [Laaniste, Mari]. Mõru maik; Paul-Eerik Rummo. Luuletused; Ilona Laaman. Mulle ei meeldinud su nimi; Lehte Hainsalu. Viis minutit pärast vihma ja Kukelokuti; Maimu Berg. Ära; Kalju Kruusa. Meeleolu; Ervin Õunapuu. Eesti gootika ja Teie mälestuseks, kes iganes te olete ja kus asute; Ilmar Talve. Kevad Eestis, Kutsumatu külaline ja Kolmas kodumaa

Aasta puitehitis 2013 on suvemaja Laulasmaal

Index Scriptorium Estoniae

2013-01-01

Konkursi "Aasta puitehitis 2013" võidutöö: Öö-Öö Arhitektide (Ülo-Tarmo Stöör, Lembit-Kaur Stöör, Kätlin Ölluk) projekteeritud rannamaja Laulasmaal. Liimpuidu eripreemia: Kadarik Tüür Arhitektide projekteeritud jalgrattahoidla Rakveres. Fassaadipreemia: Tarmo Piirmetsa projekteeritud suveköök Hiiumaal. Vineeri eripreemia: Andres Sevtšuki ja Raul Kalvo projekteeritud vineerist paviljon Singapuris

Smoking cessation

OpenAIRE

Dunn, L; Ogilvie, A; Pelkonen, M; Notkola, I; Tukiainen, H; Tervahauta, M; Tuomilehto, J; Nissinen, A

2002-01-01

Kirandeep Kaur, Shivani Juneja, Sandeep KaushalDepartment of Pharmacology, Dayanand Medical College and Hospital, Ludhiana, Punjab, IndiaWith reference to the article published under the title "Pharmacologic agents for smoking cessation: A clinical review", we would like to add some information related to smoking cessation therapy among pregnant females. In that article, in the nicotine replacement therapy section, pregnancy has been considered as a contraindication...

Efficacy of L-carnitine supplementation on frailty status and its biomarkers, nutritional status, and physical and cognitive function among prefrail older adults: a double-blind, randomized, placebo-controlled clinical trial

OpenAIRE

Badrasawi,Manal; Shahar,Suzana; Abd Manaf,Zahara; Rajab,Nor Fadilah; KAS,Devinder

2016-01-01

M Badrasawi,1,2 Suzana Shahar,1 AM Zahara,1 R Nor Fadilah,3 Devinder Kaur Ajit Singh4 1Dietetic Programme, School of Healthcare Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia; 2Nutrition Program, Faulty of Applied Sciences, Palestine Polytechnic University, Hebron, Palestine; 3Biomedical Programme, School of Healthcare Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia; 4Physiotherapy Programme, School of Rehabilitation Sciences, Universiti Kebangsaan Malaysia...

Baltisaksa naiste esimesed luulekogud ja -põimikud / Kairit Kaur

Index Scriptorium Estoniae

Kaur, Kairit

2011-01-01

Lähemalt vaadeldakse kolme luulekogu: Benigna Gottliebe "Suurt ristikandjat" (1777), Elisa von der Recke "Suursuguse Kuramaa daami vaimulikke laule" (1780) ning "preili von Grafina" tuntud luuletajanna värsipõimikut ajakirjas "Nordische Miscellaneen" - "Ühe kõrgemast seisusest liivimaalanna mitmesuguseid luuletusi ja laule" (1781)

Network Coded Software Defined Networking

DEFF Research Database (Denmark)

Krigslund, Jeppe; Hansen, Jonas; Roetter, Daniel Enrique Lucani

2015-01-01

Software Defined Networking (SDN) and Network Coding (NC) are two key concepts in networking that have garnered a large attention in recent years. On the one hand, SDN's potential to virtualize services in the Internet allows a large flexibility not only for routing data, but also to manage....... This paper advocates for the use of SDN to bring about future Internet and 5G network services by incorporating network coding (NC) functionalities. The inherent flexibility of both SDN and NC provides a fertile ground to envision more efficient, robust, and secure networking designs, that may also...

Modeling the citation network by network cosmology.

Science.gov (United States)

Xie, Zheng; Ouyang, Zhenzheng; Zhang, Pengyuan; Yi, Dongyun; Kong, Dexing

2015-01-01

Citation between papers can be treated as a causal relationship. In addition, some citation networks have a number of similarities to the causal networks in network cosmology, e.g., the similar in-and out-degree distributions. Hence, it is possible to model the citation network using network cosmology. The casual network models built on homogenous spacetimes have some restrictions when describing some phenomena in citation networks, e.g., the hot papers receive more citations than other simultaneously published papers. We propose an inhomogenous causal network model to model the citation network, the connection mechanism of which well expresses some features of citation. The node growth trend and degree distributions of the generated networks also fit those of some citation networks well.

Network Coded Software Defined Networking

DEFF Research Database (Denmark)

Hansen, Jonas; Roetter, Daniel Enrique Lucani; Krigslund, Jeppe

2015-01-01

Software defined networking has garnered large attention due to its potential to virtualize services in the Internet, introducing flexibility in the buffering, scheduling, processing, and routing of data in network routers. SDN breaks the deadlock that has kept Internet network protocols stagnant...... for decades, while applications and physical links have evolved. This article advocates for the use of SDN to bring about 5G network services by incorporating network coding (NC) functionalities. The latter constitutes a major leap forward compared to the state-of-the- art store and forward Internet paradigm...

Green mobile networks a networking perspective

CERN Document Server

Ansari, Nirwan

2016-01-01

Combines the hot topics of energy efficiency and next generation mobile networking, examining techniques and solutions. Green communications is a very hot topic. Ever increasing mobile network bandwidth rates significantly impacts on operating costs due to aggregate network energy consumption. As such, design on 4G networks and beyond has increasingly started to focus on 'energy efficiency' or so-called 'green' networks. Many techniques and solutions have been proposed to enhance the energy efficiency of mobile networks, yet no book has provided an in-depth analysis of the energy consumption issues in mobile networks nor offers detailed theories, tools and solutions for solving the energy efficiency problems.

Topology of the European Network of Earth Observation Networks and the need for an European Network of Networks

Science.gov (United States)

Masó, Joan; Serral, Ivette; McCallum, Ian; Blonda, Palma; Plag, Hans-Peter

2016-04-01

ConnectinGEO (Coordinating an Observation Network of Networks EnCompassing saTellite and IN-situ to fill the Gaps in European Observations" is an H2020 Coordination and Support Action with the primary goal of linking existing Earth Observation networks with science and technology (S&T) communities, the industry sector, the Group on Earth Observations (GEO), and Copernicus. The project will end in February 2017. ConnectinGEO will initiate a European Network of Earth Observation Networks (ENEON) that will encompass space-based, airborne and in-situ observations networks. ENEON will be composed of project partners representing thematic observation networks along with the GEOSS Science and Technology Stakeholder Network, GEO Communities of Practices, Copernicus services, Sentinel missions and in-situ support data representatives, representatives of the European space-based, airborne and in-situ observations networks. This communication presents the complex panorama of Earth Observations Networks in Europe. The list of networks is classified by discipline, variables, geospatial scope, etc. We also capture the membership and relations with other networks and umbrella organizations like GEO. The result is a complex interrelation between networks that can not be clearly expressed in a flat list. Technically the networks can be represented as nodes with relations between them as lines connecting the nodes in a graph. We have chosen RDF as a language and an AllegroGraph 3.3 triple store that is visualized in several ways using for example Gruff 5.7. Our final aim is to identify gaps in the EO Networks and justify the need for a more structured coordination between them.

Baltika kvartal = Baltika Quarter / Maris Kerge, Kadri Kerge

Index Scriptorium Estoniae

Kerge, Maris

2010-01-01

Rekonstrueeritud Baltika tööstushoonest: Moetänavast ja AS Baltika büroodest. Projekteerija, sisearhitektuur büroode osas: Studio 3 (4 arhitekti), büroo Kolm Pluss Üks (9 arhitekti). Sisearhitektuur Moetänava osas: Pekka Porkanen, Maris Kerge, Ott Kangur, Maire Milder, Lembit-Kaur Stöör, Ülo-Tarmo Stöör, Lauri Eltermaa, Pärtel Eelma. Projekt: 2007-2009, valmis: 2009

Cloud networking understanding cloud-based data center networks

CERN Document Server

Lee, Gary

2014-01-01

Cloud Networking: Understanding Cloud-Based Data Center Networks explains the evolution of established networking technologies into distributed, cloud-based networks. Starting with an overview of cloud technologies, the book explains how cloud data center networks leverage distributed systems for network virtualization, storage networking, and software-defined networking. The author offers insider perspective to key components that make a cloud network possible such as switch fabric technology and data center networking standards. The final chapters look ahead to developments in architectures

Deterministic bound for avionics switched networks according to networking features using network calculus

Directory of Open Access Journals (Sweden)

Feng HE

2017-12-01

Full Text Available The state of the art avionics system adopts switched networks for airborne communications. A major concern in the design of the networks is the end-to-end guarantee ability. Analytic methods have been developed to compute the worst-case delays according to the detailed configurations of flows and networks within avionics context, such as network calculus and trajectory approach. It still lacks a relevant method to make a rapid performance estimation according to some typically switched networking features, such as networking scale, bandwidth utilization and average flow rate. The goal of this paper is to establish a deterministic upper bound analysis method by using these networking features instead of the complete network configurations. Two deterministic upper bounds are proposed from network calculus perspective: one is for a basic estimation, and another just shows the benefits from grouping strategy. Besides, a mathematic expression for grouping ability is established based on the concept of network connecting degree, which illustrates the possibly minimal grouping benefit. For a fully connected network with 4 switches and 12 end systems, the grouping ability coming from grouping strategy is 15–20%, which just coincides with the statistical data (18–22% from the actual grouping advantage. Compared with the complete network calculus analysis method for individual flows, the effectiveness of the two deterministic upper bounds is no less than 38% even with remarkably varied packet lengths. Finally, the paper illustrates the design process for an industrial Avionics Full DupleX switched Ethernet (AFDX networking case according to the two deterministic upper bounds and shows that a better control for network connecting, when designing a switched network, can improve the worst-case delays dramatically. Keywords: Deterministic bound, Grouping ability, Network calculus, Networking features, Switched networks

Cascading Failures and Recovery in Networks of Networks

Science.gov (United States)

Havlin, Shlomo

Network science have been focused on the properties of a single isolated network that does not interact or depends on other networks. In reality, many real-networks, such as power grids, transportation and communication infrastructures interact and depend on other networks. I will present a framework for studying the vulnerability and the recovery of networks of interdependent networks. In interdependent networks, when nodes in one network fail, they cause dependent nodes in other networks to also fail. This is also the case when some nodes like certain locations play a role in two networks -multiplex. This may happen recursively and can lead to a cascade of failures and to a sudden fragmentation of the system. I will present analytical solutions for the critical threshold and the giant component of a network of n interdependent networks. I will show, that the general theory has many novel features that are not present in the classical network theory. When recovery of components is possible global spontaneous recovery of the networks and hysteresis phenomena occur and the theory suggests an optimal repairing strategy of system of systems. I will also show that interdependent networks embedded in space are significantly more vulnerable compared to non embedded networks. In particular, small localized attacks may lead to cascading failures and catastrophic consequences.Thus, analyzing data of real network of networks is highly required to understand the system vulnerability. DTRA, ONR, Israel Science Foundation.

A Phytochemical Analysis of Espeletia nana Cuatrec. a Midget Espeletiinae from Paramo Ortiz, Venezuela

Directory of Open Access Journals (Sweden)

Alexis Peña

2012-12-01

Full Text Available Espeletia nana Cuatrec is a resinous plant, member of the Espeletiinae Subtribe. It is a small size frailejón, 25cm high, found at Páramo Ortiz, Trujillo State, Venezuela. Leaves and roots were separately extracted with a 3:1 mixture of hexane-diethyl ether. Aliquotes of the acidic fractions were methylated and inspected by GC-MS. It was found that the resin from the leaves contained kaurenic acid (1a, 34.6%, grandiflorenic acid (2a, 40.1%, 15-ent-acetoxy-kaur-16-en-19-oic acid (3a, 8%, and 15-hidroxy- ent-kaur-16-en-19-oic acid (3a, 13%. The roots acid fraction contained 38% 1a, 39,6% 2b, 8.5% 3a, and 13.9% 4a. The GC-MS analysis of the leaves neutral fraction yielded 43% kaurenal (5, 3% kaurenol (6, 13% ruilopeziol (7a, 7% epi-ruilopeziol, 25% of nonacontane and 8% of entriacontane. On the other hand the roots resin contained 88%, 5.7% of 6, 2.5% 7a, 1.0% 7b, but only 1.5% of waxes. The bulk extracts were submitted to flash chromatography, leading to the isolation of pure kaurenes which were identified by direct comparison with authentic samples.

Data center networks and network architecture

Science.gov (United States)

Esaki, Hiroshi

2014-02-01

This paper discusses and proposes the architectural framework, which is for data center networks. The data center networks require new technical challenges, and it would be good opportunity to change the functions, which are not need in current and future networks. Based on the observation and consideration on data center networks, this paper proposes; (i) Broadcast-free layer 2 network (i.e., emulation of broadcast at the end-node), (ii) Full-mesh point-to-point pipes, and (iii) IRIDES (Invitation Routing aDvertisement for path Engineering System).

Vulnerability and controllability of networks of networks

International Nuclear Information System (INIS)

Liu, Xueming; Peng, Hao; Gao, Jianxi

2015-01-01

Network science is a highly interdisciplinary field ranging from natural science to engineering technology and it has been applied to model complex systems and used to explain their behaviors. Most previous studies have been focus on isolated networks, but many real-world networks do in fact interact with and depend on other networks via dependency connectivities, forming “networks of networks” (NON). The interdependence between networks has been found to largely increase the vulnerability of interacting systems, when a node in one network fails, it usually causes dependent nodes in other networks to fail, which, in turn, may cause further damage on the first network and result in a cascade of failures with sometimes catastrophic consequences, e.g., electrical blackouts caused by the interdependence of power grids and communication networks. The vulnerability of a NON can be analyzed by percolation theory that can be used to predict the critical threshold where a NON collapses. We review here the analytic framework for analyzing the vulnerability of NON, which yields novel percolation laws for n-interdependent networks and also shows that percolation theory of a single network studied extensively in physics and mathematics in the last 50 years is a specific limited case of the more general case of n interacting networks. Understanding the mechanism behind the cascading failure in NON enables us finding methods to decrease the vulnerability of the natural systems and design of more robust infrastructure systems. By examining the vulnerability of NON under targeted attack and studying the real interdependent systems, we find two methods to decrease the systems vulnerability: (1) protect the high-degree nodes, and (2) increase the degree correlation between networks. Furthermore, the ultimate proof of our understanding of natural and technological systems is reflected in our ability to control them. We also review the recent studies and challenges on the

Network coding at different layers in wireless networks

CERN Document Server

2016-01-01

This book focuses on how to apply network coding at different layers in wireless networks – including MAC, routing, and TCP – with special focus on cognitive radio networks. It discusses how to select parameters in network coding (e.g., coding field, number of packets involved, and redundant information ration) in order to be suitable for the varying wireless environments. The book explores how to deploy network coding in MAC to improve network performance and examines joint network coding with opportunistic routing to improve the successful rate of routing. In regards to TCP and network coding, the text considers transport layer protocol working with network coding to overcome the transmission error rate, particularly with how to use the ACK feedback of TCP to enhance the efficiency of network coding. The book pertains to researchers and postgraduate students, especially whose interests are in opportunistic routing and TCP in cognitive radio networks.

Introduction to the Mymaridae (Hymenoptera of Bangladesh

Directory of Open Access Journals (Sweden)

John T. Huber

2017-05-01

Full Text Available An identification key to the 15 genera of Mymaridae found so far in Bangladesh is given, based on about 520 specimens collected using yellow pan traps placed in agricultural habitats and at the edge of ponds, mainly at Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur. Species already reported from Bangladesh are listed and three more are added: Acmopolynema orientale (Narayanan, Subba Rao & Kaur, Himopolynema hishimonus Taguchi, and Mymar pulchellum Curtis.

Children's influence on family purchase decision in India.

OpenAIRE

Desai, Tanvi

2008-01-01

The importance of children in purchase decision making has grown over the years. They not only make purchase decisions for personal consumption but they also influence family purchase decision-making (Kaur and Singh, 2006). This research looks at available literature, which is discussed with respect to children influence on product categories, decision-making stages, socialising agents like parents, peers and media and role of family communication in purchase decision making. Demographic vari...

Linn biennaali keskpunktis / Mare Tralla

Index Scriptorium Estoniae

Tralla, Mare, 1967-

2006-01-01

IV Liverpoli rahvusvaheline biennaal 16. IX-26. XI: "International 06" Tate Liverpoolis ja linnaruumis, "International+" linnaruumis, "John Moores 24" Walkeri galeriis, "New Contemporaries" Greenlandi tänavas jm. Hans Schabusi (sünd. 1970), Hans Peter Kuhni, Teresa Margollesi (sünd. 1963), Priscilla Monge (sünd. 1968), Jeppe Heini (sünd. 1974), Kiran Kaur Brari, Tsui Kuang-Yu (sünd. 1974) ja Esra Erseni töödest

Arhitektuuriaasta 2007 = The year 2007 in architecture / Liina Jänes

Index Scriptorium Estoniae

Jänes, Liina, 1977-

2008-01-01

Eesti Kultuurkapitali 2007. a. arhitektuuri valdkonna peapreemia pälvis Vello Asi. Arhitektuuri sihtkapital: tegevuspremia - Kalle Komissarov, arhitektuuripreemia - Kalle Vellevoog (pansionaat Pärnus Seedri t. 4), arhitektuuri- ja sisearhitektuuri preemia - Lembit-Kaur Stöör, Tõnis Kimmel, Raili Paling ja Liis Lindvere (Tallinna sünagoog), restaureerimispreemia - Aivar Roosaar (Tartu Athena kino ja konverentsikeskus), uurimistöö preemia - Silja Konsa, Urve Sinijärv, Olev Abner, Kersti Lootus, Ants Hein (teatmeteos "Eesti pargid. 1")

Overlay networks toward information networking

CERN Document Server

Tarkoma, Sasu

2010-01-01

With their ability to solve problems in massive information distribution and processing, while keeping scaling costs low, overlay systems represent a rapidly growing area of R&D with important implications for the evolution of Internet architecture. Inspired by the author's articles on content based routing, Overlay Networks: Toward Information Networking provides a complete introduction to overlay networks. Examining what they are and what kind of structures they require, the text covers the key structures, protocols, and algorithms used in overlay networks. It reviews the current state of th

Exploring network operations for data and information networks

Science.gov (United States)

Yao, Bing; Su, Jing; Ma, Fei; Wang, Xiaomin; Zhao, Xiyang; Yao, Ming

2017-01-01

Barabási and Albert, in 1999, formulated scale-free models based on some real networks: World-Wide Web, Internet, metabolic and protein networks, language or sexual networks. Scale-free networks not only appear around us, but also have high qualities in the world. As known, high quality information networks can transfer feasibly and efficiently data, clearly, their topological structures are very important for data safety. We build up network operations for constructing large scale of dynamic networks from smaller scale of network models having good property and high quality. We focus on the simplest operators to formulate complex operations, and are interesting on the closeness of operations to desired network properties.

Gradient networks on uncorrelated random scale-free networks

International Nuclear Information System (INIS)

Pan Guijun; Yan Xiaoqing; Huang Zhongbing; Ma Weichuan

2011-01-01

Uncorrelated random scale-free (URSF) networks are useful null models for checking the effects of scale-free topology on network-based dynamical processes. Here, we present a comparative study of the jamming level of gradient networks based on URSF networks and Erdos-Renyi (ER) random networks. We find that the URSF networks are less congested than ER random networks for the average degree (k)>k c (k c ∼ 2 denotes a critical connectivity). In addition, by investigating the topological properties of the two kinds of gradient networks, we discuss the relations between the topological structure and the transport efficiency of the gradient networks. These findings show that the uncorrelated scale-free structure might allow more efficient transport than the random structure.

Reconfigurable network systems and software-defined networking

OpenAIRE

Zilberman, N.; Watts, P. M.; Rotsos, C.; Moore, A. W.

2015-01-01

Modern high-speed networks have evolved from relatively static networks to highly adaptive networks facilitating dynamic reconfiguration. This evolution has influenced all levels of network design and management, introducing increased programmability and configuration flexibility. This influence has extended from the lowest level of physical hardware interfaces to the highest level of network management by software. A key representative of this evolution is the emergence of software-defined n...

Improving network management with Software Defined Networking

International Nuclear Information System (INIS)

Dzhunev, Pavel

2013-01-01

Software-defined networking (SDN) is developed as an alternative to closed networks in centers for data processing by providing a means to separate the control layer data layer switches, and routers. SDN introduces new possibilities for network management and configuration methods. In this article, we identify problems with the current state-of-the-art network configuration and management mechanisms and introduce mechanisms to improve various aspects of network management

Network Restoration for Next-Generation Communication and Computing Networks

Directory of Open Access Journals (Sweden)

B. S. Awoyemi

2018-01-01

Full Text Available Network failures are undesirable but inevitable occurrences for most modern communication and computing networks. A good network design must be robust enough to handle sudden failures, maintain traffic flow, and restore failed parts of the network within a permissible time frame, at the lowest cost achievable and with as little extra complexity in the network as possible. Emerging next-generation (xG communication and computing networks such as fifth-generation networks, software-defined networks, and internet-of-things networks have promises of fast speeds, impressive data rates, and remarkable reliability. To achieve these promises, these complex and dynamic xG networks must be built with low failure possibilities, high network restoration capacity, and quick failure recovery capabilities. Hence, improved network restoration models have to be developed and incorporated in their design. In this paper, a comprehensive study on network restoration mechanisms that are being developed for addressing network failures in current and emerging xG networks is carried out. Open-ended problems are identified, while invaluable ideas for better adaptation of network restoration to evolving xG communication and computing paradigms are discussed.

Learning Networks, Networked Learning

NARCIS (Netherlands)

Sloep, Peter; Berlanga, Adriana

2010-01-01

Sloep, P. B., & Berlanga, A. J. (2011). Learning Networks, Networked Learning [Redes de Aprendizaje, Aprendizaje en Red]. Comunicar, XIX(37), 55-63. Retrieved from http://dx.doi.org/10.3916/C37-2011-02-05

Network cosmology.

Science.gov (United States)

Krioukov, Dmitri; Kitsak, Maksim; Sinkovits, Robert S; Rideout, David; Meyer, David; Boguñá, Marián

2012-01-01

Prediction and control of the dynamics of complex networks is a central problem in network science. Structural and dynamical similarities of different real networks suggest that some universal laws might accurately describe the dynamics of these networks, albeit the nature and common origin of such laws remain elusive. Here we show that the causal network representing the large-scale structure of spacetime in our accelerating universe is a power-law graph with strong clustering, similar to many complex networks such as the Internet, social, or biological networks. We prove that this structural similarity is a consequence of the asymptotic equivalence between the large-scale growth dynamics of complex networks and causal networks. This equivalence suggests that unexpectedly similar laws govern the dynamics of complex networks and spacetime in the universe, with implications to network science and cosmology.

Network marketing on a small-world network

Science.gov (United States)

Kim, Beom Jun; Jun, Tackseung; Kim, Jeong-Yoo; Choi, M. Y.

2006-02-01

We investigate a dynamic model of network marketing in a small-world network structure artificially constructed similarly to the Watts-Strogatz network model. Different from the traditional marketing, consumers can also play the role of the manufacturer's selling agents in network marketing, which is stimulated by the referral fee the manufacturer offers. As the wiring probability α is increased from zero to unity, the network changes from the one-dimensional regular directed network to the star network where all but one player are connected to one consumer. The price p of the product and the referral fee r are used as free parameters to maximize the profit of the manufacturer. It is observed that at α=0 the maximized profit is constant independent of the network size N while at α≠0, it increases linearly with N. This is in parallel to the small-world transition. It is also revealed that while the optimal value of p stays at an almost constant level in a broad range of α, that of r is sensitive to a change in the network structure. The consumer surplus is also studied and discussed.

Weighted Scale-Free Network Properties of Ecological Network

International Nuclear Information System (INIS)

Lee, Jae Woo; Maeng, Seong Eun

2013-01-01

We investigate the scale-free network properties of the bipartite ecological network, in particular, the plant-pollinator network. In plant-pollinator network, the pollinators visit the plant to get the nectars. In contrast to the other complex network, the plant-pollinator network has not only the trophic relationships among the interacting partners but also the complexities of the coevolutionary effects. The interactions between the plant and pollinators are beneficial relations. The plant-pollinator network is a bipartite and weighted network. The networks have two types of the nodes: plant and pollinator. We consider the visiting frequency of a pollinator to a plant as the weighting value of the link. We defined the strength of a node as the sum of the weighting value of the links. We reported the cumulative distribution function (CDF) of the degree and the strength of the plant-pollinator network. The CDF of the plants followed stretched exponential functions for both degree and strength, but the CDF of the pollinators showed the power law for both degree and strength. The average strength of the links showed the nonlinear dependence on the degree of the networks.

A Network Traffic Control Enhancement Approach over Bluetooth Networks

DEFF Research Database (Denmark)

Son, L.T.; Schiøler, Henrik; Madsen, Ole Brun

2003-01-01

This paper analyzes network traffic control issues in Bluetooth data networks as convex optimization problem. We formulate the problem of maximizing of total network flows and minimizing the costs of flows. An adaptive distributed network traffic control scheme is proposed as an approximated solu...... as capacity limitations and flow requirements in the network. Simulation shows that the performance of Bluetooth networks could be improved by applying the adaptive distributed network traffic control scheme...... solution of the stated optimization problem that satisfies quality of service requirements and topologically induced constraints in Bluetooth networks, such as link capacity and node resource limitations. The proposed scheme is decentralized and complies with frequent changes of topology as well......This paper analyzes network traffic control issues in Bluetooth data networks as convex optimization problem. We formulate the problem of maximizing of total network flows and minimizing the costs of flows. An adaptive distributed network traffic control scheme is proposed as an approximated...

Network structure exploration in networks with node attributes

Science.gov (United States)

Chen, Yi; Wang, Xiaolong; Bu, Junzhao; Tang, Buzhou; Xiang, Xin

2016-05-01

Complex networks provide a powerful way to represent complex systems and have been widely studied during the past several years. One of the most important tasks of network analysis is to detect structures (also called structural regularities) embedded in networks by determining group number and group partition. Most of network structure exploration models only consider network links. However, in real world networks, nodes may have attributes that are useful for network structure exploration. In this paper, we propose a novel Bayesian nonparametric (BNP) model to explore structural regularities in networks with node attributes, called Bayesian nonparametric attribute (BNPA) model. This model does not only take full advantage of both links between nodes and node attributes for group partition via shared hidden variables, but also determine group number automatically via the Bayesian nonparametric theory. Experiments conducted on a number of real and synthetic networks show that our BNPA model is able to automatically explore structural regularities in networks with node attributes and is competitive with other state-of-the-art models.

Undermining and Strengthening Social Networks through Network Modification

Science.gov (United States)

Mellon, Jonathan; Yoder, Jordan; Evans, Daniel

2016-10-01

Social networks have well documented effects at the individual and aggregate level. Consequently it is often useful to understand how an attempt to influence a network will change its structure and consequently achieve other goals. We develop a framework for network modification that allows for arbitrary objective functions, types of modification (e.g. edge weight addition, edge weight removal, node removal, and covariate value change), and recovery mechanisms (i.e. how a network responds to interventions). The framework outlined in this paper helps both to situate the existing work on network interventions but also opens up many new possibilities for intervening in networks. In particular use two case studies to highlight the potential impact of empirically calibrating the objective function and network recovery mechanisms as well as showing how interventions beyond node removal can be optimised. First, we simulate an optimal removal of nodes from the Noordin terrorist network in order to reduce the expected number of attacks (based on empirically predicting the terrorist collaboration network from multiple types of network ties). Second, we simulate optimally strengthening ties within entrepreneurial ecosystems in six developing countries. In both cases we estimate ERGM models to simulate how a network will endogenously evolve after intervention.

"Aktsioon kuubis" mõjus õõnsalt / Kaur Garšnek

Index Scriptorium Estoniae

Garšnek, Kaur, 1983-

2009-01-01

31. jaanuaril Niguliste kirikus toimunud Pärnu nüüdismuusika päevade ja "In Graafika 2009" ühisfestivali lõpetavast performance'ist "Aktsioon kuuvis II: Dimensioonid", mis põhines Uku Masingu näidendi "Palimplatsid" epiloogil

Kasumit kasvatanud Eesti Energia hinnatõusutaotlusest ei tagane / Kaur Paves

Index Scriptorium Estoniae

Paves, Kaur

2011-01-01

Ettevõtte puhaskasumist, osaluse müügist Jordaania tütarettevõttes, elektri müügist avatud turgudel, elektrihinna tõusu taotlemisest ja uuest kliendiinfosüsteemist. Skeem: Energiahiid teenis hästi

Aasta pärast on Eestil uus valitsus / Max Kaur

Index Scriptorium Estoniae

Kaur, Max, 1969-

2003-01-01

Autori sõnul on Res Publica uus poliitika osutunud euroremonditud vanaks poliitikaks ning ta ennustab, et järgmiseks sügiseks on Eestil uus valitsuskoalitsioon, mille peaminister on keskerakondlane

Declarative Networking

CERN Document Server

Loo, Boon Thau

2012-01-01

Declarative Networking is a programming methodology that enables developers to concisely specify network protocols and services, which are directly compiled to a dataflow framework that executes the specifications. Declarative networking proposes the use of a declarative query language for specifying and implementing network protocols, and employs a dataflow framework at runtime for communication and maintenance of network state. The primary goal of declarative networking is to greatly simplify the process of specifying, implementing, deploying and evolving a network design. In addition, decla

Recent advances on failure and recovery in networks of networks

International Nuclear Information System (INIS)

Shekhtman, Louis M.; Danziger, Michael M.; Havlin, Shlomo

2016-01-01

Until recently, network science has focused on the properties of single isolated networks that do not interact or depend on other networks. However it has now been recognized that many real-networks, such as power grids, transportation systems, and communication infrastructures interact and depend on other networks. Here, we will present a review of the framework developed in recent years for studying the vulnerability and recovery of networks composed of interdependent networks. In interdependent networks, when nodes in one network fail, they cause dependent nodes in other networks to also fail. This is also the case when some nodes, like for example certain people, play a role in two networks, i.e. in a multiplex. Dependency relations may act recursively and can lead to cascades of failures concluding in sudden fragmentation of the system. We review the analytical solutions for the critical threshold and the giant component of a network of n interdependent networks. The general theory and behavior of interdependent networks has many novel features that are not present in classical network theory. Interdependent networks embedded in space are significantly more vulnerable compared to non-embedded networks. In particular, small localized attacks may lead to cascading failures and catastrophic consequences. Finally, when recovery of components is possible, global spontaneous recovery of the networks and hysteresis phenomena occur. The theory developed for this process points to an optimal repairing strategy for a network of networks. Understanding realistic effects present in networks of networks is required in order to move towards determining system vulnerability.

vhv supply networks, problems of network structure

Energy Technology Data Exchange (ETDEWEB)

Raimbault, J

1966-04-01

The present and future power requirements of the Paris area and the structure of the existing networks are discussed. The various limitations that will have to be allowed for to lay down the structure of a regional transmission network leading in the power of the large national transmission network to within the Paris built up area are described. The theoretical solution that has been adopted, and the features of its final achievement, which is planned for about the year 2000, and the intermediate stages are given. The problem of the structure of the National Power Transmission network which is to supply the regional network was studied. To solve this problem, a 730 kV voltage network will have to be introduced.

Network configuration of global R&D networks

DEFF Research Database (Denmark)

Hansen, Zaza Nadja Lee; Srai, Jagjit Singh

2011-01-01

, network configuration of global R&D has tended to focus on strategic elements with limited attention given operational effectiveness, or to interfaces with downstream manufacturing operations. Within OM literature, the drivers of configuration of global networks within, engineering, production, supply...... to R&D networks emerged, e.g. product features were more prominent in R&D networks. Furthermore, the study has shown extensive interaction with other operations, including many downstream manufacturing operations. By extending the OM configuration concepts to the configuration of R&D networks......Companies are increasingly globalising their R&D activities, both within the firms and with external partners, with consequent implications for their interaction with manufacturing operations. Previous research in R&D networks has focused on coordination, governance and support elements. However...

Innovation in Multiple Networks and Networks of Networks: The Case of the Fruit Sector in Emilia‐Romagna

Directory of Open Access Journals (Sweden)

Davide Viaggi

2013-02-01

Full Text Available In the paper we examine the issue of food systems in which farms participate in multiple networks that, for their part, tend also to be members of networks of networks. The issue is addressed through a descriptive analysis of the fruit sector in Emilia‐Romagna (Italy. The farms in the area tend to join a different network for each product/product type. Innovation networks are embedded in commercialization or input provider networks, but separate (parallel networks also exist, particularly for basic research activities. Networks of networks are largely a product of the cooperative system. The paper concludes by emphasising the need for further research in multiple networking strategies and the connection betweencommercialisation networks and innovation.

Rituximab therapy in a patient with low grade B-cell lymphoproliferative disease and concomitant acquired angioedema

Directory of Open Access Journals (Sweden)

Kaur R

2014-12-01

Full Text Available Ravdeep Kaur, Aerik Anthony Williams, Catherine Baker Swift, Jason W Caldwell Wake Forest University School of Medicine, Wake Forest University, Winston-Salem, NC, USA Abstract: Acquired angioedema is often associated with significant morbidity. An underlying lymphatic malignancy, autoimmune disorder, adenocarcinoma, or other malignancy may be present. Screening for these disorders should occur in all patients with acquired angioedema as treatment may result in resolution of angioedema. Keywords: complement, C1-INH deficiency, ecallantide, hemopathy

Applying Physical-Layer Network Coding in Wireless Networks

Directory of Open Access Journals (Sweden)

Liew SoungChang

2010-01-01

Full Text Available A main distinguishing feature of a wireless network compared with a wired network is its broadcast nature, in which the signal transmitted by a node may reach several other nodes, and a node may receive signals from several other nodes, simultaneously. Rather than a blessing, this feature is treated more as an interference-inducing nuisance in most wireless networks today (e.g., IEEE 802.11. This paper shows that the concept of network coding can be applied at the physical layer to turn the broadcast property into a capacity-boosting advantage in wireless ad hoc networks. Specifically, we propose a physical-layer network coding (PNC scheme to coordinate transmissions among nodes. In contrast to "straightforward" network coding which performs coding arithmetic on digital bit streams after they have been received, PNC makes use of the additive nature of simultaneously arriving electromagnetic (EM waves for equivalent coding operation. And in doing so, PNC can potentially achieve 100% and 50% throughput increases compared with traditional transmission and straightforward network coding, respectively, in 1D regular linear networks with multiple random flows. The throughput improvements are even larger in 2D regular networks: 200% and 100%, respectively.

Network cohesion

OpenAIRE

Cavalcanti, Tiago Vanderlei; Giannitsarou, Chrysi; Johnson, CR

2017-01-01

We define a measure of network cohesion and show how it arises naturally in a broad class of dynamic models of endogenous perpetual growth with network externalities. Via a standard growth model, we show why network cohesion is crucial for conditional convergence and explain that as cohesion increases, convergence is faster. We prove properties of network cohesion and define a network aggregator that preserves network cohesion.

Spatial networks

Science.gov (United States)

Barthélemy, Marc

2011-02-01

Complex systems are very often organized under the form of networks where nodes and edges are embedded in space. Transportation and mobility networks, Internet, mobile phone networks, power grids, social and contact networks, and neural networks, are all examples where space is relevant and where topology alone does not contain all the information. Characterizing and understanding the structure and the evolution of spatial networks is thus crucial for many different fields, ranging from urbanism to epidemiology. An important consequence of space on networks is that there is a cost associated with the length of edges which in turn has dramatic effects on the topological structure of these networks. We will thoroughly explain the current state of our understanding of how the spatial constraints affect the structure and properties of these networks. We will review the most recent empirical observations and the most important models of spatial networks. We will also discuss various processes which take place on these spatial networks, such as phase transitions, random walks, synchronization, navigation, resilience, and disease spread.

Network Ambivalence

Directory of Open Access Journals (Sweden)

Patrick Jagoda

2015-08-01

Full Text Available The language of networks now describes everything from the Internet to the economy to terrorist organizations. In distinction to a common view of networks as a universal, originary, or necessary form that promises to explain everything from neural structures to online traffic, this essay emphasizes the contingency of the network imaginary. Network form, in its role as our current cultural dominant, makes scarcely imaginable the possibility of an alternative or an outside uninflected by networks. If so many things and relationships are figured as networks, however, then what is not a network? If a network points towards particular logics and qualities of relation in our historical present, what others might we envision in the future? In  many ways, these questions are unanswerable from within the contemporary moment. Instead of seeking an avant-garde approach (to move beyond networks or opting out of networks (in some cases, to recover elements of pre-networked existence, this essay proposes a third orientation: one of ambivalence that operates as a mode of extreme presence. I propose the concept of "network aesthetics," which can be tracked across artistic media and cultural forms, as a model, style, and pedagogy for approaching interconnection in the twenty-first century. The following essay is excerpted from Network Ambivalence (Forthcoming from University of Chicago Press. 

Inferring general relations between network characteristics from specific network ensembles.

Science.gov (United States)

Cardanobile, Stefano; Pernice, Volker; Deger, Moritz; Rotter, Stefan

2012-01-01

Different network models have been suggested for the topology underlying complex interactions in natural systems. These models are aimed at replicating specific statistical features encountered in real-world networks. However, it is rarely considered to which degree the results obtained for one particular network class can be extrapolated to real-world networks. We address this issue by comparing different classical and more recently developed network models with respect to their ability to generate networks with large structural variability. In particular, we consider the statistical constraints which the respective construction scheme imposes on the generated networks. After having identified the most variable networks, we address the issue of which constraints are common to all network classes and are thus suitable candidates for being generic statistical laws of complex networks. In fact, we find that generic, not model-related dependencies between different network characteristics do exist. This makes it possible to infer global features from local ones using regression models trained on networks with high generalization power. Our results confirm and extend previous findings regarding the synchronization properties of neural networks. Our method seems especially relevant for large networks, which are difficult to map completely, like the neural networks in the brain. The structure of such large networks cannot be fully sampled with the present technology. Our approach provides a method to estimate global properties of under-sampled networks in good approximation. Finally, we demonstrate on three different data sets (C. elegans neuronal network, R. prowazekii metabolic network, and a network of synonyms extracted from Roget's Thesaurus) that real-world networks have statistical relations compatible with those obtained using regression models.

Maximum entropy networks are more controllable than preferential attachment networks

International Nuclear Information System (INIS)

Hou, Lvlin; Small, Michael; Lao, Songyang

2014-01-01

A maximum entropy (ME) method to generate typical scale-free networks has been recently introduced. We investigate the controllability of ME networks and Barabási–Albert preferential attachment networks. Our experimental results show that ME networks are significantly more easily controlled than BA networks of the same size and the same degree distribution. Moreover, the control profiles are used to provide insight into control properties of both classes of network. We identify and classify the driver nodes and analyze the connectivity of their neighbors. We find that driver nodes in ME networks have fewer mutual neighbors and that their neighbors have lower average degree. We conclude that the properties of the neighbors of driver node sensitively affect the network controllability. Hence, subtle and important structural differences exist between BA networks and typical scale-free networks of the same degree distribution. - Highlights: • The controllability of maximum entropy (ME) and Barabási–Albert (BA) networks is investigated. • ME networks are significantly more easily controlled than BA networks of the same degree distribution. • The properties of the neighbors of driver node sensitively affect the network controllability. • Subtle and important structural differences exist between BA networks and typical scale-free networks

Network Learning and Innovation in SME Formal Networks

Directory of Open Access Journals (Sweden)

Jivka Deiters

2013-02-01

Full Text Available The driver for this paper is the need to better understand the potential for learning and innovation that networks canprovide especially for small and medium sized enterprises (SMEs which comprise by far the majority of enterprises in the food sector. With the challenges the food sector is facing in the near future, learning and innovation or more focused, as it is being discussed in the paper, ‘learning for innovation’ are not just opportunities but pre‐conditions for the sustainability of the sector. Network initiatives that could provide appropriate support involve social interaction and knowledge exchange, learning, competence development, and coordination (organization and management of implementation. The analysis identifies case studies in any of these orientations which serve different stages of the innovation process: invention and implementation. The variety of network case studies cover networks linked to a focus group for training, research, orconsulting, networks dealing with focused market oriented product or process development, promotional networks, and networks for open exchange and social networking.

Interconnected networks

CERN Document Server

2016-01-01

This volume provides an introduction to and overview of the emerging field of interconnected networks which include multi layer or multiplex networks, as well as networks of networks. Such networks present structural and dynamical features quite different from those observed in isolated networks. The presence of links between different networks or layers of a network typically alters the way such interconnected networks behave – understanding the role of interconnecting links is therefore a crucial step towards a more accurate description of real-world systems. While examples of such dissimilar properties are becoming more abundant – for example regarding diffusion, robustness and competition – the root of such differences remains to be elucidated. Each chapter in this topical collection is self-contained and can be read on its own, thus making it also suitable as reference for experienced researchers wishing to focus on a particular topic.

Do Policy Networks lead to Network Governing?

DEFF Research Database (Denmark)

Damgaard, Bodil

This paper challenges the notion that creation of local policy networks necessarily leads to network governing. Through actor-centred case studies in the area of municipally implemented employment policy in Denmark it was found that the local governing mode is determined mainly by the municipality......’s approach to local co-governing as well as by the capacity and interest of key private actors. It is argued that national legislation requesting the creation of local policy networks was not enough to assure network governing and the case studies show that local policy networks may subsist also under...... hierarchical governing modes. Reasons why hierarchical governing modes prevail over network governing in some settings are identified pointing to both actor borne and structural factors. Output indicators of the four cases do not show that a particular governing mode is more efficient in its employment policy...

Application of Butterfly Clos-Network in Network-on-Chip

Directory of Open Access Journals (Sweden)

Hui Liu

2014-01-01

Full Text Available This paper studied the topology of NoC (Network-on-Chip. By combining the characteristics of the Clos network and butterfly network, a new topology named BFC (Butterfly Clos-network network was proposed. This topology integrates several modules, which belongs to the same layer but different dimensions, into a new module. In the BFC network, a bidirectional link is used to complete information exchange, instead of information exchange between different layers in the original network. During the routing period, other nondestination nodes can be used as middle stages to transfer data packets to complete the routing mission. Therefore, this topology has the characteristic of multistage. Simulation analyses show that BFC inherits the rich path diversity of Clos network, and it has a better performance than butterfly network in throughput and delay in a quite congested traffic pattern.

Biological Networks Entropies: Examples in Neural Memory Networks, Genetic Regulation Networks and Social Epidemic Networks

Directory of Open Access Journals (Sweden)

Jacques Demongeot

2018-01-01

Full Text Available Networks used in biological applications at different scales (molecule, cell and population are of different types: neuronal, genetic, and social, but they share the same dynamical concepts, in their continuous differential versions (e.g., non-linear Wilson-Cowan system as well as in their discrete Boolean versions (e.g., non-linear Hopfield system; in both cases, the notion of interaction graph G(J associated to its Jacobian matrix J, and also the concepts of frustrated nodes, positive or negative circuits of G(J, kinetic energy, entropy, attractors, structural stability, etc., are relevant and useful for studying the dynamics and the robustness of these systems. We will give some general results available for both continuous and discrete biological networks, and then study some specific applications of three new notions of entropy: (i attractor entropy, (ii isochronal entropy and (iii entropy centrality; in three domains: a neural network involved in the memory evocation, a genetic network responsible of the iron control and a social network accounting for the obesity spread in high school environment.

Temporal networks

CERN Document Server

Saramäki, Jari

2013-01-01

The concept of temporal networks is an extension of complex networks as a modeling framework to include information on when interactions between nodes happen. Many studies of the last decade examine how the static network structure affect dynamic systems on the network. In this traditional approach  the temporal aspects are pre-encoded in the dynamic system model. Temporal-network methods, on the other hand, lift the temporal information from the level of system dynamics to the mathematical representation of the contact network itself. This framework becomes particularly useful for cases where there is a lot of structure and heterogeneity both in the timings of interaction events and the network topology. The advantage compared to common static network approaches is the ability to design more accurate models in order to explain and predict large-scale dynamic phenomena (such as, e.g., epidemic outbreaks and other spreading phenomena). On the other hand, temporal network methods are mathematically and concept...

Mitigating Inter-Network Interference in LoRa Networks

OpenAIRE

Voigt, Thiemo; Bor, Martin; Roedig, Utz; Alonso, Juan

2017-01-01

Long Range (LoRa) is a popular technology used to construct Low-Power Wide-Area Network (LPWAN) networks. Given the popularity of LoRa it is likely that multiple independent LoRa networks are deployed in close proximity. In this situation, neighbouring networks interfere and methods have to be found to combat this interference. In this paper we investigate the use of directional antennae and the use of multiple base stations as methods of dealing with inter-network interference. Directional a...

Maximal network reliability for a stochastic power transmission network

International Nuclear Information System (INIS)

Lin, Yi-Kuei; Yeh, Cheng-Ta

2011-01-01

Many studies regarded a power transmission network as a binary-state network and constructed it with several arcs and vertices to evaluate network reliability. In practice, the power transmission network should be stochastic because each arc (transmission line) combined with several physical lines is multistate. Network reliability is the probability that the network can transmit d units of electric power from a power plant (source) to a high voltage substation at a specific area (sink). This study focuses on searching for the optimal transmission line assignment to the power transmission network such that network reliability is maximized. A genetic algorithm based method integrating the minimal paths and the Recursive Sum of Disjoint Products is developed to solve this assignment problem. A real power transmission network is adopted to demonstrate the computational efficiency of the proposed method while comparing with the random solution generation approach.

Network workshop

DEFF Research Database (Denmark)

Bruun, Jesper; Evans, Robert Harry

2014-01-01

This paper describes the background for, realisation of and author reflections on a network workshop held at ESERA2013. As a new research area in science education, networks offer a unique opportunity to visualise and find patterns and relationships in complicated social or academic network data....... These include student relations and interactions and epistemic and linguistic networks of words, concepts and actions. Network methodology has already found use in science education research. However, while networks hold the potential for new insights, they have not yet found wide use in the science education...... research community. With this workshop, participants were offered a way into network science based on authentic educational research data. The workshop was constructed as an inquiry lesson with emphasis on user autonomy. Learning activities had participants choose to work with one of two cases of networks...

On the Design of Energy Efficient Optical Networks with Software Defined Networking Control Across Core and Access Networks

DEFF Research Database (Denmark)

Wang, Jiayuan; Yan, Ying; Dittmann, Lars

2013-01-01

This paper presents a Software Defined Networking (SDN) control plane based on an overlay GMPLS control model. The SDN control platform manages optical core networks (WDM/DWDM networks) and the associated access networks (GPON networks), which makes it possible to gather global information...... and enable wider areas' energy efficiency networking. The energy related information of the networks and the types of the traffic flows are collected and utilized for the end-to-end QoS provision. Dynamic network simulation results show that by applying different routing algorithms according to the type...... of traffic in the core networks, the energy efficiency of the network is improved without compromising the quality of service....

Exploring biological network structure with clustered random networks

Directory of Open Access Journals (Sweden)

Bansal Shweta

2009-12-01

Full Text Available Abstract Background Complex biological systems are often modeled as networks of interacting units. Networks of biochemical interactions among proteins, epidemiological contacts among hosts, and trophic interactions in ecosystems, to name a few, have provided useful insights into the dynamical processes that shape and traverse these systems. The degrees of nodes (numbers of interactions and the extent of clustering (the tendency for a set of three nodes to be interconnected are two of many well-studied network properties that can fundamentally shape a system. Disentangling the interdependent effects of the various network properties, however, can be difficult. Simple network models can help us quantify the structure of empirical networked systems and understand the impact of various topological properties on dynamics. Results Here we develop and implement a new Markov chain simulation algorithm to generate simple, connected random graphs that have a specified degree sequence and level of clustering, but are random in all other respects. The implementation of the algorithm (ClustRNet: Clustered Random Networks provides the generation of random graphs optimized according to a local or global, and relative or absolute measure of clustering. We compare our algorithm to other similar methods and show that ours more successfully produces desired network characteristics. Finding appropriate null models is crucial in bioinformatics research, and is often difficult, particularly for biological networks. As we demonstrate, the networks generated by ClustRNet can serve as random controls when investigating the impacts of complex network features beyond the byproduct of degree and clustering in empirical networks. Conclusion ClustRNet generates ensembles of graphs of specified edge structure and clustering. These graphs allow for systematic study of the impacts of connectivity and redundancies on network function and dynamics. This process is a key step in

Modelling dendritic ecological networks in space: anintegrated network perspective

Science.gov (United States)

Peterson, Erin E.; Ver Hoef, Jay M.; Isaak, Dan J.; Falke, Jeffrey A.; Fortin, Marie-Josée; Jordon, Chris E.; McNyset, Kristina; Monestiez, Pascal; Ruesch, Aaron S.; Sengupta, Aritra; Som, Nicholas; Steel, E. Ashley; Theobald, David M.; Torgersen, Christian E.; Wenger, Seth J.

2013-01-01

Dendritic ecological networks (DENs) are a unique form of ecological networks that exhibit a dendritic network topology (e.g. stream and cave networks or plant architecture). DENs have a dual spatial representation; as points within the network and as points in geographical space. Consequently, some analytical methods used to quantify relationships in other types of ecological networks, or in 2-D space, may be inadequate for studying the influence of structure and connectivity on ecological processes within DENs. We propose a conceptual taxonomy of network analysis methods that account for DEN characteristics to varying degrees and provide a synthesis of the different approaches within

Energy-aware virtual network embedding in flexi-grid networks.

Science.gov (United States)

Lin, Rongping; Luo, Shan; Wang, Haoran; Wang, Sheng

2017-11-27

Network virtualization technology has been proposed to allow multiple heterogeneous virtual networks (VNs) to coexist on a shared substrate network, which increases the utilization of the substrate network. Efficiently mapping VNs on the substrate network is a major challenge on account of the VN embedding (VNE) problem. Meanwhile, energy efficiency has been widely considered in the network design in terms of operation expenses and the ecological awareness. In this paper, we aim to solve the energy-aware VNE problem in flexi-grid optical networks. We provide an integer linear programming (ILP) formulation to minimize the electricity cost of each arriving VN request. We also propose a polynomial-time heuristic algorithm where virtual links are embedded sequentially to keep a reasonable acceptance ratio and maintain a low electricity cost. Numerical results show that the heuristic algorithm performs closely to the ILP for a small size network, and we also demonstrate its applicability to larger networks.

Resilient Disaster Network Based on Software Defined Cognitive Wireless Network Technology

Directory of Open Access Journals (Sweden)

Goshi Sato

2015-01-01

Full Text Available In order to temporally recover the information network infrastructure in disaster areas from the Great East Japan Earthquake in 2011, various wireless network technologies such as satellite IP network, 3G, and Wi-Fi were effectively used. However, since those wireless networks are individually introduced and installed but not totally integrated, some of networks were congested due to the sudden network traffic generation and unbalanced traffic distribution, and eventually the total network could not effectively function. In this paper, we propose a disaster resilient network which integrates various wireless networks into a cognitive wireless network that users can use as an access network to the Internet at the serious disaster occurrence. We designed and developed the disaster resilient network based on software defined network (SDN technology to automatically select the best network link and route among the possible access networks to the Internet by periodically monitoring their network states and evaluate those using extended AHP method. In order to verify the usefulness of our proposed system, a prototype system is constructed and its performance is evaluated.

Deploying temporary networks for upscaling of sparse network stations

Science.gov (United States)

Coopersmith, Evan J.; Cosh, Michael H.; Bell, Jesse E.; Kelly, Victoria; Hall, Mark; Palecki, Michael A.; Temimi, Marouane

2016-10-01

Soil observations networks at the national scale play an integral role in hydrologic modeling, drought assessment, agricultural decision support, and our ability to understand climate change. Understanding soil moisture variability is necessary to apply these measurements to model calibration, business and consumer applications, or even human health issues. The installation of soil moisture sensors as sparse, national networks is necessitated by limited financial resources. However, this results in the incomplete sampling of the local heterogeneity of soil type, vegetation cover, topography, and the fine spatial distribution of precipitation events. To this end, temporary networks can be installed in the areas surrounding a permanent installation within a sparse network. The temporary networks deployed in this study provide a more representative average at the 3 km and 9 km scales, localized about the permanent gauge. The value of such temporary networks is demonstrated at test sites in Millbrook, New York and Crossville, Tennessee. The capacity of a single U.S. Climate Reference Network (USCRN) sensor set to approximate the average of a temporary network at the 3 km and 9 km scales using a simple linear scaling function is tested. The capacity of a temporary network to provide reliable estimates with diminishing numbers of sensors, the temporal stability of those networks, and ultimately, the relationship of the variability of those networks to soil moisture conditions at the permanent sensor are investigated. In this manner, this work demonstrates the single-season installation of a temporary network as a mechanism to characterize the soil moisture variability at a permanent gauge within a sparse network.

NETWORK, HOW? Perceptions of business people on networking practices

Directory of Open Access Journals (Sweden)

Saskia De Klerk

2010-12-01

Full Text Available Purpose: The purpose of this paper was to contribute to literature on networking from a South African perspective. Literature on networking is mainly concentrated on the European and American contexts with homogeneous groups and traditional divisions. The business landscape of South Africa thus requires more investigation. Problem investigated: Literature regarding networking in an South African context with its dynamic business environment is limited. This article addresses the concerns of how South African business owners and managers perceive networking in their businesses and specifically focus on the South African perspective. Therefore, the focus is on the perceptions of business owners and managers on current networking practices in South Africa. Methodology: A qualitative research design to uncover the rich underlying feelings of business owners and managers was used. The qualitative enquiry consisted of five focus group discussions (n=41 participants among prominent business owners and managers in the Gauteng Province, South Africa. The Gauteng Province was selected since it is the economic and innovation hub of South Africa. Findings and implications: The main findings showed the following main themes of networking that emerged from the data, and included (1 networking as a skill versus a natural ability; (2 the motivation behind networking; (3 the loci of networking; (4 the type of relationships that determine the character of the network; and (5 the relationship characteristics of successful networking. The main contribution of this is that there seems to be different networking situations and applications for different circumstances. According to the participants, it seems that networking in the South African landscape appears to be either relationship or business based. Originality and value of the research: The value of these findings lies in the fact that they contribute to networking literature from a South African perspective

Localizing and placement of network node functions in a network

NARCIS (Netherlands)

Strijkers, R.J.; Meulenhoff, P.J.

2014-01-01

The invention enables placement and use of a network node function in a second network node instead of using the network node function in a first network node. The network node function is e.g. a server function or a router function. The second network node is typically located in or close to the

Creative Network Communities in the Translocal Space of Digital Networks

Directory of Open Access Journals (Sweden)

Rasa Smite

2013-01-01

Full Text Available What should sociological research be in the age of Web 2.0? Considering that the task of “network sociology” is not only empirical research but also the interpretation of tendencies of the network culture, this research explores the rise of network communities within Eastern and Western Europe in the early Internet era. I coined the term creative networks to distinguish these early creative and social activities from today’s popular social networking. Thus I aimed to interpret the meaning of social action; the motivation of creative community actors, their main fields of activities and social organization forms; and the potential that these early developments contain for the future sustainability of networks. Data comprise interviews with networking experts and founders and members of various networks. Investigating respondents’ motivations for creating online networks and communities, and interpreting those terms, allows for comparing the creative networks of the 1990s with today’s social networks and for drawing conclusions.

Comparison analysis on vulnerability of metro networks based on complex network

Science.gov (United States)

Zhang, Jianhua; Wang, Shuliang; Wang, Xiaoyuan

2018-04-01

This paper analyzes the networked characteristics of three metro networks, and two malicious attacks are employed to investigate the vulnerability of metro networks based on connectivity vulnerability and functionality vulnerability. Meanwhile, the networked characteristics and vulnerability of three metro networks are compared with each other. The results show that Shanghai metro network has the largest transport capacity, Beijing metro network has the best local connectivity and Guangzhou metro network has the best global connectivity, moreover Beijing metro network has the best homogeneous degree distribution. Furthermore, we find that metro networks are very vulnerable subjected to malicious attacks, and Guangzhou metro network has the best topological structure and reliability among three metro networks. The results indicate that the proposed methodology is feasible and effective to investigate the vulnerability and to explore better topological structure of metro networks.

REVIEWER LIST – 2014

OpenAIRE

Chief Editor

2014-01-01

REVIEWER LIST – 2014 The Editorial Team would like to thank all those who gave generously of their time and expertise in reviewing the papers for the Indian Journal of Community Health in 2014.AAarti Kapil, New Delhi, IndiaAbhishek SinghAmandeep Kaur, Haldwani, IndiaAmit Kaushik, Safai, IndiaAnu Bhardwaj, Ambala, IndiaAnurag Chaudary, Ludhiana, IndiaA R BondArpan YagnikArvind Kumar Singh, Gorakhpur, IndiaAshish Yadav, Meerut, IndiaAthar Ansari, Aligarh, India BBaridalyne Nongkynrih, New Delhi...

Milliste plaanidega lähed vastu uuele õppeaastale? / Triinu Lepp, Gleb Tšurbanov, Erik Paemurru, Steven Huang...[jt.

Index Scriptorium Estoniae

2008-01-01

Küsimusele vastavad hariduskolleegiumi algkooli 3. klassi õpilane Egert, prantsuse lütseumi 12. klassi õpilane Triinu Lepp, Sillamäe kutsekooli 3. kursuse õpilane Gleb Tšurbanov, Tallinna reaalkooli 11. klassi õpilane Erik Paemurru, Toronto Crescenti keskkooli õpilane Steven Huang, kunstiakadeemia muinsuskaitse- ja restaureerimisosakonna õppejõud Jaan Tamm, Tartu Miina Härma gümnaasiumi 2. a klassi õpilane Erki Külaots, Tallinna 21. kooli 11. klassi õpilane Sander Kaur ja Tapa gümnaasiumi 7. klassi õpilane Evelin Orgse

Hierarchical Network Design

DEFF Research Database (Denmark)

Thomadsen, Tommy

2005-01-01

Communication networks are immensely important today, since both companies and individuals use numerous services that rely on them. This thesis considers the design of hierarchical (communication) networks. Hierarchical networks consist of layers of networks and are well-suited for coping...... with changing and increasing demands. Two-layer networks consist of one backbone network, which interconnects cluster networks. The clusters consist of nodes and links, which connect the nodes. One node in each cluster is a hub node, and the backbone interconnects the hub nodes of each cluster and thus...... the clusters. The design of hierarchical networks involves clustering of nodes, hub selection, and network design, i.e. selection of links and routing of ows. Hierarchical networks have been in use for decades, but integrated design of these networks has only been considered for very special types of networks...

Network architecture in a converged optical + IP network

Science.gov (United States)

Wakim, Walid; Zottmann, Harald

2012-01-01

As demands on Provider Networks continue to grow at exponential rates, providers are forced to evaluate how to continue to grow the network while increasing service velocity, enhancing resiliency while decreasing the total cost of ownership (TCO). The bandwidth growth that networks are experiencing is in the form packet based multimedia services such as video, video conferencing, gaming, etc... mixed with Over the Top (OTT) content providers such as Netflix, and the customer's expectations that best effort is not enough you end up with a situation that forces the provider to analyze how to gain more out of the network with less cost. In this paper we will discuss changes in the network that are driving us to a tighter integration between packet and optical layers and how to improve on today's multi - layer inefficiencies to drive down network TCO and provide for a fully integrated and dynamic network that will decrease time to revenue.

Telecommunication networks

CERN Document Server

Iannone, Eugenio

2011-01-01

Many argue that telecommunications network infrastructure is the most impressive and important technology ever developed. Analyzing the telecom market's constantly evolving trends, research directions, infrastructure, and vital needs, Telecommunication Networks responds with revolutionized engineering strategies to optimize network construction. Omnipresent in society, telecom networks integrate a wide range of technologies. These include quantum field theory for the study of optical amplifiers, software architectures for network control, abstract algebra required to design error correction co

Temporal networks

Science.gov (United States)

Holme, Petter; Saramäki, Jari

2012-10-01

A great variety of systems in nature, society and technology-from the web of sexual contacts to the Internet, from the nervous system to power grids-can be modeled as graphs of vertices coupled by edges. The network structure, describing how the graph is wired, helps us understand, predict and optimize the behavior of dynamical systems. In many cases, however, the edges are not continuously active. As an example, in networks of communication via e-mail, text messages, or phone calls, edges represent sequences of instantaneous or practically instantaneous contacts. In some cases, edges are active for non-negligible periods of time: e.g., the proximity patterns of inpatients at hospitals can be represented by a graph where an edge between two individuals is on throughout the time they are at the same ward. Like network topology, the temporal structure of edge activations can affect dynamics of systems interacting through the network, from disease contagion on the network of patients to information diffusion over an e-mail network. In this review, we present the emergent field of temporal networks, and discuss methods for analyzing topological and temporal structure and models for elucidating their relation to the behavior of dynamical systems. In the light of traditional network theory, one can see this framework as moving the information of when things happen from the dynamical system on the network, to the network itself. Since fundamental properties, such as the transitivity of edges, do not necessarily hold in temporal networks, many of these methods need to be quite different from those for static networks. The study of temporal networks is very interdisciplinary in nature. Reflecting this, even the object of study has many names-temporal graphs, evolving graphs, time-varying graphs, time-aggregated graphs, time-stamped graphs, dynamic networks, dynamic graphs, dynamical graphs, and so on. This review covers different fields where temporal graphs are considered

Linear network theory

CERN Document Server

Sander, K F

1964-01-01

Linear Network Theory covers the significant algebraic aspect of network theory, with minimal reference to practical circuits. The book begins the presentation of network analysis with the exposition of networks containing resistances only, and follows it up with a discussion of networks involving inductance and capacity by way of the differential equations. Classification and description of certain networks, equivalent networks, filter circuits, and network functions are also covered. Electrical engineers, technicians, electronics engineers, electricians, and students learning the intricacies

From network structure to network reorganization: implications for adult neurogenesis

International Nuclear Information System (INIS)

Schneider-Mizell, Casey M; Zochowski, Michal R; Sander, Leonard M; Parent, Jack M; Ben-Jacob, Eshel

2010-01-01

Networks can be dynamical systems that undergo functional and structural reorganization. One example of such a process is adult hippocampal neurogenesis, in which new cells are continuously born and incorporate into the existing network of the dentate gyrus region of the hippocampus. Many of these introduced cells mature and become indistinguishable from established neurons, joining the existing network. Activity in the network environment is known to promote birth, survival and incorporation of new cells. However, after epileptogenic injury, changes to the connectivity structure around the neurogenic niche are known to correlate with aberrant neurogenesis. The possible role of network-level changes in the development of epilepsy is not well understood. In this paper, we use a computational model to investigate how the structural and functional outcomes of network reorganization, driven by addition of new cells during neurogenesis, depend on the original network structure. We find that there is a stable network topology that allows the network to incorporate new neurons in a manner that enhances activity of the persistently active region, but maintains global network properties. In networks having other connectivity structures, new cells can greatly alter the distribution of firing activity and destroy the initial activity patterns. We thus find that new cells are able to provide focused enhancement of network only for small-world networks with sufficient inhibition. Network-level deviations from this topology, such as those caused by epileptogenic injury, can set the network down a path that develops toward pathological dynamics and aberrant structural integration of new cells

Correlated network of networks enhances robustness against catastrophic failures.

Science.gov (United States)

Min, Byungjoon; Zheng, Muhua

2018-01-01

Networks in nature rarely function in isolation but instead interact with one another with a form of a network of networks (NoN). A network of networks with interdependency between distinct networks contains instability of abrupt collapse related to the global rule of activation. As a remedy of the collapse instability, here we investigate a model of correlated NoN. We find that the collapse instability can be removed when hubs provide the majority of interconnections and interconnections are convergent between hubs. Thus, our study identifies a stable structure of correlated NoN against catastrophic failures. Our result further suggests a plausible way to enhance network robustness by manipulating connection patterns, along with other methods such as controlling the state of node based on a local rule.

How to construct the statistic network? An association network of herbaceous

Directory of Open Access Journals (Sweden)

WenJun Zhang

2012-06-01

Full Text Available In present study I defined a new type of network, the statistic network. The statistic network is a weighted and non-deterministic network. In the statistic network, a connection value, i.e., connection weight, represents connection strength and connection likelihood between two nodes and its absolute value falls in the interval (0,1]. The connection value is expressed as a statistical measure such as correlation coefficient, association coefficient, or Jaccard coefficient, etc. In addition, all connections of the statistic network can be statistically tested for their validity. A connection is true if the connection value is statistically significant. If all connection values of a node are not statistically significant, it is an isolated node. An isolated node has not any connection to other nodes in the statistic network. Positive and negative connection values denote distinct connectiontypes (positive or negative association or interaction. In the statistic network, two nodes with the greater connection value will show more similar trend in the change of their states. At any time we can obtain a sample network of the statistic network. A sample network is a non-weighted and deterministic network. Thestatistic network, in particular the plant association network that constructed from field sampling, is mostly an information network. Most of the interspecific relationships in plant community are competition and cooperation. Therefore in comparison to animal networks, the methodology of statistic network is moresuitable to construct plant association networks. Some conclusions were drawn from this study: (1 in the plant association network, most connections are weak and positive interactions. The association network constructed from Spearman rank correlation has most connections and isolated taxa are fewer. From net linear correlation,linear correlation, to Spearman rank correlation, the practical number of connections and connectance in the

The Network Completion Problem: Inferring Missing Nodes and Edges in Networks

Energy Technology Data Exchange (ETDEWEB)

Kim, M; Leskovec, J

2011-11-14

Network structures, such as social networks, web graphs and networks from systems biology, play important roles in many areas of science and our everyday lives. In order to study the networks one needs to first collect reliable large scale network data. While the social and information networks have become ubiquitous, the challenge of collecting complete network data still persists. Many times the collected network data is incomplete with nodes and edges missing. Commonly, only a part of the network can be observed and we would like to infer the unobserved part of the network. We address this issue by studying the Network Completion Problem: Given a network with missing nodes and edges, can we complete the missing part? We cast the problem in the Expectation Maximization (EM) framework where we use the observed part of the network to fit a model of network structure, and then we estimate the missing part of the network using the model, re-estimate the parameters and so on. We combine the EM with the Kronecker graphs model and design a scalable Metropolized Gibbs sampling approach that allows for the estimation of the model parameters as well as the inference about missing nodes and edges of the network. Experiments on synthetic and several real-world networks show that our approach can effectively recover the network even when about half of the nodes in the network are missing. Our algorithm outperforms not only classical link-prediction approaches but also the state of the art Stochastic block modeling approach. Furthermore, our algorithm easily scales to networks with tens of thousands of nodes.

Network maintenance

CERN Multimedia

GS Department

2009-01-01

A site-wide network maintenance operation has been scheduled for Saturday 28 February. Most of the network devices of the general purpose network will be upgraded to a newer software version, in order to improve our network monitoring capabilities. This will result in a series of short (2-5 minutes) random interruptions everywhere on the CERN sites throughout the day. This upgrade will not affect the Computer Centre itself, Building 613, the Technical Network and the LHC experiments, dedicated networks at the pits. For further details of this intervention, please contact Netops by phone 74927 or e-mail mailto:Netops@cern.ch. IT/CS Group

Network maintenance

CERN Multimedia

IT Department

2009-01-01

A site wide network maintenance has been scheduled for Saturday 28 February. Most of the network devices of the General Purpose network will be upgraded to a newer software version, in order to improve our network monitoring capabilities. This will result in a series of short (2-5 minutes) random interruptions everywhere on the CERN sites along this day. This upgrade will not affect: the Computer centre itself, building 613, the Technical Network and the LHC experiments dedicated networks at the pits. Should you need more details on this intervention, please contact Netops by phone 74927 or email mailto:Netops@cern.ch. IT/CS Group

Network reconfiguration and neuronal plasticity in rhythm-generating networks.

Science.gov (United States)

Koch, Henner; Garcia, Alfredo J; Ramirez, Jan-Marino

2011-12-01

Neuronal networks are highly plastic and reconfigure in a state-dependent manner. The plasticity at the network level emerges through multiple intrinsic and synaptic membrane properties that imbue neurons and their interactions with numerous nonlinear properties. These properties are continuously regulated by neuromodulators and homeostatic mechanisms that are critical to maintain not only network stability and also adapt networks in a short- and long-term manner to changes in behavioral, developmental, metabolic, and environmental conditions. This review provides concrete examples from neuronal networks in invertebrates and vertebrates, and illustrates that the concepts and rules that govern neuronal networks and behaviors are universal.

Psychology and social networks: a dynamic network theory perspective.

Science.gov (United States)

Westaby, James D; Pfaff, Danielle L; Redding, Nicholas

2014-04-01

Research on social networks has grown exponentially in recent years. However, despite its relevance, the field of psychology has been relatively slow to explain the underlying goal pursuit and resistance processes influencing social networks in the first place. In this vein, this article aims to demonstrate how a dynamic network theory perspective explains the way in which social networks influence these processes and related outcomes, such as goal achievement, performance, learning, and emotional contagion at the interpersonal level of analysis. The theory integrates goal pursuit, motivation, and conflict conceptualizations from psychology with social network concepts from sociology and organizational science to provide a taxonomy of social network role behaviors, such as goal striving, system supporting, goal preventing, system negating, and observing. This theoretical perspective provides psychologists with new tools to map social networks (e.g., dynamic network charts), which can help inform the development of change interventions. Implications for social, industrial-organizational, and counseling psychology as well as conflict resolution are discussed, and new opportunities for research are highlighted, such as those related to dynamic network intelligence (also known as cognitive accuracy), levels of analysis, methodological/ethical issues, and the need to theoretically broaden the study of social networking and social media behavior. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

Statistical network analysis for analyzing policy networks

DEFF Research Database (Denmark)

Robins, Garry; Lewis, Jenny; Wang, Peng

2012-01-01

and policy network methodology is the development of statistical modeling approaches that can accommodate such dependent data. In this article, we review three network statistical methods commonly used in the current literature: quadratic assignment procedures, exponential random graph models (ERGMs......To analyze social network data using standard statistical approaches is to risk incorrect inference. The dependencies among observations implied in a network conceptualization undermine standard assumptions of the usual general linear models. One of the most quickly expanding areas of social......), and stochastic actor-oriented models. We focus most attention on ERGMs by providing an illustrative example of a model for a strategic information network within a local government. We draw inferences about the structural role played by individuals recognized as key innovators and conclude that such an approach...

Animal transportation networks

Science.gov (United States)

Perna, Andrea; Latty, Tanya

2014-01-01

Many group-living animals construct transportation networks of trails, galleries and burrows by modifying the environment to facilitate faster, safer or more efficient movement. Animal transportation networks can have direct influences on the fitness of individuals, whereas the shape and structure of transportation networks can influence community dynamics by facilitating contacts between different individuals and species. In this review, we discuss three key areas in the study of animal transportation networks: the topological properties of networks, network morphogenesis and growth, and the behaviour of network users. We present a brief primer on elements of network theory, and then discuss the different ways in which animal groups deal with the fundamental trade-off between the competing network properties of travel efficiency, robustness and infrastructure cost. We consider how the behaviour of network users can impact network efficiency, and call for studies that integrate both network topology and user behaviour. We finish with a prospectus for future research. PMID:25165598

ENERGY AWARE NETWORK: BAYESIAN BELIEF NETWORKS BASED DECISION MANAGEMENT SYSTEM

Directory of Open Access Journals (Sweden)

Santosh Kumar Chaudhari

2011-06-01

Full Text Available A Network Management System (NMS plays a very important role in managing an ever-evolving telecommunication network. Generally an NMS monitors & maintains the health of network elements. The growing size of the network warrants extra functionalities from the NMS. An NMS provides all kinds of information about networks which can be used for other purposes apart from monitoring & maintaining networks like improving QoS & saving energy in the network. In this paper, we add another dimension to NMS services, namely, making an NMS energy aware. We propose a Decision Management System (DMS framework which uses a machine learning technique called Bayesian Belief Networks (BBN, to make the NMS energy aware. The DMS is capable of analysing and making control decisions based on network traffic. We factor in the cost of rerouting and power saving per port. Simulations are performed on standard network topologies, namely, ARPANet and IndiaNet. It is found that ~2.5-6.5% power can be saved.

Analyzing Multimode Wireless Sensor Networks Using the Network Calculus

Directory of Open Access Journals (Sweden)

Xi Jin

2015-01-01

Full Text Available The network calculus is a powerful tool to analyze the performance of wireless sensor networks. But the original network calculus can only model the single-mode wireless sensor network. In this paper, we combine the original network calculus with the multimode model to analyze the maximum delay bound of the flow of interest in the multimode wireless sensor network. There are two combined methods A-MM and N-MM. The method A-MM models the whole network as a multimode component, and the method N-MM models each node as a multimode component. We prove that the maximum delay bound computed by the method A-MM is tighter than or equal to that computed by the method N-MM. Experiments show that our proposed methods can significantly decrease the analytical delay bound comparing with the separate flow analysis method. For the large-scale wireless sensor network with 32 thousands of sensor nodes, our proposed methods can decrease about 70% of the analytical delay bound.

Local Social Networks

DEFF Research Database (Denmark)

Sapuppo, Antonio; Sørensen, Lene Tolstrup

2011-01-01

Online social networks have become essential for many users in their daily communication. Through a combination of the online social networks with opportunistic networks, a new concept arises: Local Social Networks. The target of local social networks is to promote social networking benefits...... in physical environment in order to leverage personal affinities in the users' surroundings. The purpose of this paper is to present and discuss the concept of local social networks as a new social communication system. Particularly, the preliminary architecture and the prototype of local social networks...

From Offline Social Networks to Online Social Networks: Changes in Entrepreneurship

Directory of Open Access Journals (Sweden)

Yang SONG

2015-01-01

Full Text Available The paper reviewed studies of entrepreneurship based on the emergency of online social networks. Similar to offline social networks, entrepreneurs’ online social networks have their own unique characteristics. We first reviewed the offline network based research on entrepreneurship. Then we reviewed the studies of entrepreneurship in the context of online social networks including those focusing on topics of network structures and network ties. We highlighted online network communities based on the data collected from LinkedIn, Facebook and Twitter. Our research implies that both researcher and entrepreneurs are facing new opportunities due to the emergence of online social networks.

Investigation of the network delay on Profibus-DP based network

OpenAIRE

Yılmaz, C.; Gürdal, O.; Sayan, H.H.

2008-01-01

The mathematical model of the network-induced delay control systems (NDCS) is given. Also the role of the NDCS’s components such as controller, sensor and network environment on the network-induced delay are included in the mathematical model of the system. The network delay is investigated on Profibus-DP based network application and experimental results obtained are presented graphically. The experimental results obtained show that the network induced delay is randomly changed according to ...

Vulnerability of complex networks

Science.gov (United States)

Mishkovski, Igor; Biey, Mario; Kocarev, Ljupco

2011-01-01

We consider normalized average edge betweenness of a network as a metric of network vulnerability. We suggest that normalized average edge betweenness together with is relative difference when certain number of nodes and/or edges are removed from the network is a measure of network vulnerability, called vulnerability index. Vulnerability index is calculated for four synthetic networks: Erdős-Rényi (ER) random networks, Barabási-Albert (BA) model of scale-free networks, Watts-Strogatz (WS) model of small-world networks, and geometric random networks. Real-world networks for which vulnerability index is calculated include: two human brain networks, three urban networks, one collaboration network, and two power grid networks. We find that WS model of small-world networks and biological networks (human brain networks) are the most robust networks among all networks studied in the paper.

Friendly network robotics; Friendly network robotics

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

This paper summarizes the research results on the friendly network robotics in fiscal 1996. This research assumes an android robot as an ultimate robot and the future robot system utilizing computer network technology. The robot aiming at human daily work activities in factories or under extreme environments is required to work under usual human work environments. The human robot with similar size, shape and functions to human being is desirable. Such robot having a head with two eyes, two ears and mouth can hold a conversation with human being, can walk with two legs by autonomous adaptive control, and has a behavior intelligence. Remote operation of such robot is also possible through high-speed computer network. As a key technology to use this robot under coexistence with human being, establishment of human coexistent robotics was studied. As network based robotics, use of robots connected with computer networks was also studied. In addition, the R-cube (R{sup 3}) plan (realtime remote control robot technology) was proposed. 82 refs., 86 figs., 12 tabs.

Networked Identities

DEFF Research Database (Denmark)

Ryberg, Thomas; Larsen, Malene Charlotte

2008-01-01

of CoPs we shall argue that the metaphor or theory of networked learning is itself confronted with some central tensions and challenges that need to be addressed. We then explore these theoretical and analytic challenges to the network metaphor, through an analysis of a Danish social networking site. We......In this article we take up a critique of the concept of Communities of Practice (CoP) voiced by several authors, who suggest that networks may provide a better metaphor to understand social forms of organisation and learning. Through a discussion of the notion of networked learning and the critique...... argue that understanding meaning-making and ‘networked identities’ may be relevant analytic entry points in navigating the challenges....

Location based Network Optimizations for Mobile Wireless Networks

DEFF Research Database (Denmark)

Nielsen, Jimmy Jessen

selection in Wi-Fi networks and predictive handover optimization in heterogeneous wireless networks. The investigations in this work have indicated that location based network optimizations are beneficial compared to typical link measurement based approaches. Especially the knowledge of geographical...

Network Performance Improvement under Epidemic Failures in Optical Transport Networks

DEFF Research Database (Denmark)

Fagertun, Anna Manolova; Ruepp, Sarah Renée

2013-01-01

In this paper we investigate epidemic failure spreading in large- scale GMPLS-controlled transport networks. By evaluating the effect of the epidemic failure spreading on the network, we design several strategies for cost-effective network performance improvement via differentiated repair times....... First we identify the most vulnerable and the most strategic nodes in the network. Then, via extensive simulations we show that strategic placement of resources for improved failure recovery has better performance than randomly assigning lower repair times among the network nodes. Our OPNET simulation...... model can be used during the network planning process for facilitating cost- effective network survivability design....

Network Traffic Prediction Based on Deep Belief Network and Spatiotemporal Compressive Sensing in Wireless Mesh Backbone Networks

Directory of Open Access Journals (Sweden)

Laisen Nie

2018-01-01

Full Text Available Wireless mesh network is prevalent for providing a decentralized access for users and other intelligent devices. Meanwhile, it can be employed as the infrastructure of the last few miles connectivity for various network applications, for example, Internet of Things (IoT and mobile networks. For a wireless mesh backbone network, it has obtained extensive attention because of its large capacity and low cost. Network traffic prediction is important for network planning and routing configurations that are implemented to improve the quality of service for users. This paper proposes a network traffic prediction method based on a deep learning architecture and the Spatiotemporal Compressive Sensing method. The proposed method first adopts discrete wavelet transform to extract the low-pass component of network traffic that describes the long-range dependence of itself. Then, a prediction model is built by learning a deep architecture based on the deep belief network from the extracted low-pass component. Otherwise, for the remaining high-pass component that expresses the gusty and irregular fluctuations of network traffic, the Spatiotemporal Compressive Sensing method is adopted to predict it. Based on the predictors of two components, we can obtain a predictor of network traffic. From the simulation, the proposed prediction method outperforms three existing methods.

Experimental performance evaluation of software defined networking (SDN) based data communication networks for large scale flexi-grid optical networks.

Science.gov (United States)

Zhao, Yongli; He, Ruiying; Chen, Haoran; Zhang, Jie; Ji, Yuefeng; Zheng, Haomian; Lin, Yi; Wang, Xinbo

2014-04-21

Software defined networking (SDN) has become the focus in the current information and communication technology area because of its flexibility and programmability. It has been introduced into various network scenarios, such as datacenter networks, carrier networks, and wireless networks. Optical transport network is also regarded as an important application scenario for SDN, which is adopted as the enabling technology of data communication networks (DCN) instead of general multi-protocol label switching (GMPLS). However, the practical performance of SDN based DCN for large scale optical networks, which is very important for the technology selection in the future optical network deployment, has not been evaluated up to now. In this paper we have built a large scale flexi-grid optical network testbed with 1000 virtual optical transport nodes to evaluate the performance of SDN based DCN, including network scalability, DCN bandwidth limitation, and restoration time. A series of network performance parameters including blocking probability, bandwidth utilization, average lightpath provisioning time, and failure restoration time have been demonstrated under various network environments, such as with different traffic loads and different DCN bandwidths. The demonstration in this work can be taken as a proof for the future network deployment.

Networks around entrepreneurs

DEFF Research Database (Denmark)

Bertelsen, Rasmus Gjedssø; Ashourizadeh, Shayegheh; Jensen, Kent Wickstrøm

2017-01-01

Purpose: Entrepreneurs are networking with others to get advice for their businesses. The networking differs between men and women; notably, men are more often networking in the public sphere and women are more often networking in the private sphere. The aim here is to account for how such gender......Purpose: Entrepreneurs are networking with others to get advice for their businesses. The networking differs between men and women; notably, men are more often networking in the public sphere and women are more often networking in the private sphere. The aim here is to account for how...... such gendering of entrepreneurs’ networks differ between societies and cultures. Research Design: Based on survey data from the Global Entrepreneurships Monitor, a sample of 16,365 entrepreneurs is used to compare the gendering of entrepreneurs’ networks in China, and five countries largely located around...... the Persian Gulf, namely Yemen, Iran, Saudi Arabia, Qatar and United Arab Emirates. Findings: Analyses show that female entrepreneurs tend to have slightly larger private sphere networks than male entrepreneurs. The differences between male and female entrepreneurs’ networking in the public sphere...

Networks: structure and action : steering in and steering by policy networks

NARCIS (Netherlands)

Dassen, A.

2010-01-01

This thesis explores the opportunities to build a structural policy network model that is rooted in social network theories. By making a distinction between a process of steering in networks, and a process of steering by networks, it addresses the effects of network structures on network dynamics as

Modelling dendritic ecological networks in space: An integrated network perspective

Science.gov (United States)

Erin E. Peterson; Jay M. Ver Hoef; Dan J. Isaak; Jeffrey A. Falke; Marie-Josee Fortin; Chris E. Jordan; Kristina McNyset; Pascal Monestiez; Aaron S. Ruesch; Aritra Sengupta; Nicholas Som; E. Ashley Steel; David M. Theobald; Christian E. Torgersen; Seth J. Wenger

2013-01-01

Dendritic ecological networks (DENs) are a unique form of ecological networks that exhibit a dendritic network topology (e.g. stream and cave networks or plant architecture). DENs have a dual spatial representation; as points within the network and as points in geographical space. Consequently, some analytical methods used to quantify relationships in other types of...

Framework for network modularization and Bayesian network analysis to investigate the perturbed metabolic network

Directory of Open Access Journals (Sweden)

Kim Hyun

2011-12-01

Full Text Available Abstract Background Genome-scale metabolic network models have contributed to elucidating biological phenomena, and predicting gene targets to engineer for biotechnological applications. With their increasing importance, their precise network characterization has also been crucial for better understanding of the cellular physiology. Results We herein introduce a framework for network modularization and Bayesian network analysis (FMB to investigate organism’s metabolism under perturbation. FMB reveals direction of influences among metabolic modules, in which reactions with similar or positively correlated flux variation patterns are clustered, in response to specific perturbation using metabolic flux data. With metabolic flux data calculated by constraints-based flux analysis under both control and perturbation conditions, FMB, in essence, reveals the effects of specific perturbations on the biological system through network modularization and Bayesian network analysis at metabolic modular level. As a demonstration, this framework was applied to the genetically perturbed Escherichia coli metabolism, which is a lpdA gene knockout mutant, using its genome-scale metabolic network model. Conclusions After all, it provides alternative scenarios of metabolic flux distributions in response to the perturbation, which are complementary to the data obtained from conventionally available genome-wide high-throughput techniques or metabolic flux analysis.

Framework for network modularization and Bayesian network analysis to investigate the perturbed metabolic network.

Science.gov (United States)

Kim, Hyun Uk; Kim, Tae Yong; Lee, Sang Yup

2011-01-01

Genome-scale metabolic network models have contributed to elucidating biological phenomena, and predicting gene targets to engineer for biotechnological applications. With their increasing importance, their precise network characterization has also been crucial for better understanding of the cellular physiology. We herein introduce a framework for network modularization and Bayesian network analysis (FMB) to investigate organism's metabolism under perturbation. FMB reveals direction of influences among metabolic modules, in which reactions with similar or positively correlated flux variation patterns are clustered, in response to specific perturbation using metabolic flux data. With metabolic flux data calculated by constraints-based flux analysis under both control and perturbation conditions, FMB, in essence, reveals the effects of specific perturbations on the biological system through network modularization and Bayesian network analysis at metabolic modular level. As a demonstration, this framework was applied to the genetically perturbed Escherichia coli metabolism, which is a lpdA gene knockout mutant, using its genome-scale metabolic network model. After all, it provides alternative scenarios of metabolic flux distributions in response to the perturbation, which are complementary to the data obtained from conventionally available genome-wide high-throughput techniques or metabolic flux analysis.

Virtualized Network Function Orchestration System and Experimental Network Based QR Recognition for a 5G Mobile Access Network

Directory of Open Access Journals (Sweden)

Misun Ahn

2017-12-01

Full Text Available This paper proposes a virtualized network function orchestration system based on Network Function Virtualization (NFV, one of the main technologies in 5G mobile networks. This system should provide connectivity between network devices and be able to create flexible network function and distribution. This system focuses more on access networks. By experimenting with various scenarios of user service established and activated in a network, we examine whether rapid adoption of new service is possible and whether network resources can be managed efficiently. The proposed method is based on Bluetooth transfer technology and mesh networking to provide automatic connections between network machines and on a Docker flat form, which is a container virtualization technology for setting and managing key functions. Additionally, the system includes a clustering and recovery measure regarding network function based on the Docker platform. We will briefly introduce the QR code perceived service as a user service to examine the proposal and based on this given service, we evaluate the function of the proposal and present analysis. Through the proposed approach, container relocation has been implemented according to a network device’s CPU usage and we confirm successful service through function evaluation on a real test bed. We estimate QR code recognition speed as the amount of network equipment is gradually increased, improving user service and confirm that the speed of recognition is increased as the assigned number of network devices is increased by the user service.

A Network of Networks Perspective on Global Trade.

Science.gov (United States)

Maluck, Julian; Donner, Reik V

2015-01-01

Mutually intertwined supply chains in contemporary economy result in a complex network of trade relationships with a highly non-trivial topology that varies with time. In order to understand the complex interrelationships among different countries and economic sectors, as well as their dynamics, a holistic view on the underlying structural properties of this network is necessary. This study employs multi-regional input-output data to decompose 186 national economies into 26 industry sectors and utilizes the approach of interdependent networks to analyze the substructure of the resulting international trade network for the years 1990-2011. The partition of the network into national economies is observed to be compatible with the notion of communities in the sense of complex network theory. By studying internal versus cross-subgraph contributions to established complex network metrics, new insights into the architecture of global trade are obtained, which allow to identify key elements of global economy. Specifically, financial services and business activities dominate domestic trade whereas electrical and machinery industries dominate foreign trade. In order to further specify each national sector's role individually, (cross-)clustering coefficients and cross-betweenness are obtained for different pairs of subgraphs. The corresponding analysis reveals that specific industrial sectors tend to favor distinct directionality patterns and that the cross-clustering coefficient for geographically close country pairs is remarkably high, indicating that spatial factors are still of paramount importance for the organization of trade patterns in modern economy. Regarding the evolution of the trade network's substructure, globalization is well-expressed by trends of several structural characteristics (e.g., link density and node strength) in the interacting network framework. Extreme events, such as the financial crisis 2008/2009, are manifested as anomalies superimposed to

COalitions in COOperation Networks (COCOON): Social Network Analysis and Game Theory to Enhance Cooperation Networks

NARCIS (Netherlands)

Sie, Rory

2012-01-01

Sie, R. L. L. (2012). COalitions in COOperation Networks (COCOON): Social Network Analysis and Game Theory to Enhance Cooperation Networks (Unpublished doctoral dissertation). September, 28, 2012, Open Universiteit in the Netherlands (CELSTEC), Heerlen, The Netherlands.

Managing Network Partitions in Structured P2P Networks

Science.gov (United States)

Shafaat, Tallat M.; Ghodsi, Ali; Haridi, Seif

Structured overlay networks form a major class of peer-to-peer systems, which are touted for their abilities to scale, tolerate failures, and self-manage. Any long-lived Internet-scale distributed system is destined to face network partitions. Consequently, the problem of network partitions and mergers is highly related to fault-tolerance and self-management in large-scale systems. This makes it a crucial requirement for building any structured peer-to-peer systems to be resilient to network partitions. Although the problem of network partitions and mergers is highly related to fault-tolerance and self-management in large-scale systems, it has hardly been studied in the context of structured peer-to-peer systems. Structured overlays have mainly been studied under churn (frequent joins/failures), which as a side effect solves the problem of network partitions, as it is similar to massive node failures. Yet, the crucial aspect of network mergers has been ignored. In fact, it has been claimed that ring-based structured overlay networks, which constitute the majority of the structured overlays, are intrinsically ill-suited for merging rings. In this chapter, we motivate the problem of network partitions and mergers in structured overlays. We discuss how a structured overlay can automatically detect a network partition and merger. We present an algorithm for merging multiple similar ring-based overlays when the underlying network merges. We examine the solution in dynamic conditions, showing how our solution is resilient to churn during the merger, something widely believed to be difficult or impossible. We evaluate the algorithm for various scenarios and show that even when falsely detecting a merger, the algorithm quickly terminates and does not clutter the network with many messages. The algorithm is flexible as the tradeoff between message complexity and time complexity can be adjusted by a parameter.

Enabling software defined networking experiments in networked critical infrastructures

Directory of Open Access Journals (Sweden)

Béla Genge

2014-05-01

Full Text Available Nowadays, the fact that Networked Critical Infrastructures (NCI, e.g., power plants, water plants, oil and gas distribution infrastructures, and electricity grids, are targeted by significant cyber threats is well known. Nevertheless, recent research has shown that specific characteristics of NCI can be exploited in the enabling of more efficient mitigation techniques, while novel techniques from the field of IP networks can bring significant advantages. In this paper we explore the interconnection of NCI communication infrastructures with Software Defined Networking (SDN-enabled network topologies. SDN provides the means to create virtual networking services and to implement global networking decisions. It relies on OpenFlow to enable communication with remote devices and has been recently categorized as the “Next Big Technology”, which will revolutionize the way decisions are implemented in switches and routers. Therefore, the paper documents the first steps towards enabling an SDN-NCI and presents the impact of a Denial of Service experiment over traffic resulting from an XBee sensor network which is routed across an emulated SDN network.

Spatiotemporal Recurrent Convolutional Networks for Traffic Prediction in Transportation Networks

Directory of Open Access Journals (Sweden)

Haiyang Yu

2017-06-01

Full Text Available Predicting large-scale transportation network traffic has become an important and challenging topic in recent decades. Inspired by the domain knowledge of motion prediction, in which the future motion of an object can be predicted based on previous scenes, we propose a network grid representation method that can retain the fine-scale structure of a transportation network. Network-wide traffic speeds are converted into a series of static images and input into a novel deep architecture, namely, spatiotemporal recurrent convolutional networks (SRCNs, for traffic forecasting. The proposed SRCNs inherit the advantages of deep convolutional neural networks (DCNNs and long short-term memory (LSTM neural networks. The spatial dependencies of network-wide traffic can be captured by DCNNs, and the temporal dynamics can be learned by LSTMs. An experiment on a Beijing transportation network with 278 links demonstrates that SRCNs outperform other deep learning-based algorithms in both short-term and long-term traffic prediction.

Spatiotemporal Recurrent Convolutional Networks for Traffic Prediction in Transportation Networks.

Science.gov (United States)

Yu, Haiyang; Wu, Zhihai; Wang, Shuqin; Wang, Yunpeng; Ma, Xiaolei

2017-06-26

Predicting large-scale transportation network traffic has become an important and challenging topic in recent decades. Inspired by the domain knowledge of motion prediction, in which the future motion of an object can be predicted based on previous scenes, we propose a network grid representation method that can retain the fine-scale structure of a transportation network. Network-wide traffic speeds are converted into a series of static images and input into a novel deep architecture, namely, spatiotemporal recurrent convolutional networks (SRCNs), for traffic forecasting. The proposed SRCNs inherit the advantages of deep convolutional neural networks (DCNNs) and long short-term memory (LSTM) neural networks. The spatial dependencies of network-wide traffic can be captured by DCNNs, and the temporal dynamics can be learned by LSTMs. An experiment on a Beijing transportation network with 278 links demonstrates that SRCNs outperform other deep learning-based algorithms in both short-term and long-term traffic prediction.

Evaluation of Network Reliability for Computer Networks with Multiple Sources

Directory of Open Access Journals (Sweden)

Yi-Kuei Lin

2012-01-01

Full Text Available Evaluating the reliability of a network with multiple sources to multiple sinks is a critical issue from the perspective of quality management. Due to the unrealistic definition of paths of network models in previous literature, existing models are not appropriate for real-world computer networks such as the Taiwan Advanced Research and Education Network (TWAREN. This paper proposes a modified stochastic-flow network model to evaluate the network reliability of a practical computer network with multiple sources where data is transmitted through several light paths (LPs. Network reliability is defined as being the probability of delivering a specified amount of data from the sources to the sink. It is taken as a performance index to measure the service level of TWAREN. This paper studies the network reliability of the international portion of TWAREN from two sources (Taipei and Hsinchu to one sink (New York that goes through a submarine and land surface cable between Taiwan and the United States.

Network science

CERN Document Server

Barabasi, Albert-Laszlo

2016-01-01

Networks are everywhere, from the Internet, to social networks, and the genetic networks that determine our biological existence. Illustrated throughout in full colour, this pioneering textbook, spanning a wide range of topics from physics to computer science, engineering, economics and the social sciences, introduces network science to an interdisciplinary audience. From the origins of the six degrees of separation to explaining why networks are robust to random failures, the author explores how viruses like Ebola and H1N1 spread, and why it is that our friends have more friends than we do. Using numerous real-world examples, this innovatively designed text includes clear delineation between undergraduate and graduate level material. The mathematical formulas and derivations are included within Advanced Topics sections, enabling use at a range of levels. Extensive online resources, including films and software for network analysis, make this a multifaceted companion for anyone with an interest in network sci...

Accelerating networks

International Nuclear Information System (INIS)

Smith, David M D; Onnela, Jukka-Pekka; Johnson, Neil F

2007-01-01

Evolving out-of-equilibrium networks have been under intense scrutiny recently. In many real-world settings the number of links added per new node is not constant but depends on the time at which the node is introduced in the system. This simple idea gives rise to the concept of accelerating networks, for which we review an existing definition and-after finding it somewhat constrictive-offer a new definition. The new definition provided here views network acceleration as a time dependent property of a given system as opposed to being a property of the specific algorithm applied to grow the network. The definition also covers both unweighted and weighted networks. As time-stamped network data becomes increasingly available, the proposed measures may be easily applied to such empirical datasets. As a simple case study we apply the concepts to study the evolution of three different instances of Wikipedia, namely, those in English, German, and Japanese, and find that the networks undergo different acceleration regimes in their evolution

Network traffic anomaly prediction using Artificial Neural Network

Science.gov (United States)

Ciptaningtyas, Hening Titi; Fatichah, Chastine; Sabila, Altea

2017-03-01

As the excessive increase of internet usage, the malicious software (malware) has also increase significantly. Malware is software developed by hacker for illegal purpose(s), such as stealing data and identity, causing computer damage, or denying service to other user[1]. Malware which attack computer or server often triggers network traffic anomaly phenomena. Based on Sophos's report[2], Indonesia is the riskiest country of malware attack and it also has high network traffic anomaly. This research uses Artificial Neural Network (ANN) to predict network traffic anomaly based on malware attack in Indonesia which is recorded by Id-SIRTII/CC (Indonesia Security Incident Response Team on Internet Infrastructure/Coordination Center). The case study is the highest malware attack (SQL injection) which has happened in three consecutive years: 2012, 2013, and 2014[4]. The data series is preprocessed first, then the network traffic anomaly is predicted using Artificial Neural Network and using two weight update algorithms: Gradient Descent and Momentum. Error of prediction is calculated using Mean Squared Error (MSE) [7]. The experimental result shows that MSE for SQL Injection is 0.03856. So, this approach can be used to predict network traffic anomaly.

Phoebus: Network Middleware for Next-Generation Network Computing

Energy Technology Data Exchange (ETDEWEB)

Martin Swany

2012-06-16

The Phoebus project investigated algorithms, protocols, and middleware infrastructure to improve end-to-end performance in high speed, dynamic networks. The Phoebus system essentially serves as an adaptation point for networks with disparate capabilities or provisioning. This adaptation can take a variety of forms including acting as a provisioning agent across multiple signaling domains, providing transport protocol adaptation points, and mapping between distributed resource reservation paradigms and the optical network control plane. We have successfully developed the system and demonstrated benefits. The Phoebus system was deployed in Internet2 and in ESnet, as well as in GEANT2, RNP in Brazil and over international links to Korea and Japan. Phoebus is a system that implements a new protocol and associated forwarding infrastructure for improving throughput in high-speed dynamic networks. It was developed to serve the needs of large DOE applications on high-performance networks. The idea underlying the Phoebus model is to embed Phoebus Gateways (PGs) in the network as on-ramps to dynamic circuit networks. The gateways act as protocol translators that allow legacy applications to use dedicated paths with high performance.

Identification of important nodes in directed biological networks: a network motif approach.

Directory of Open Access Journals (Sweden)

Pei Wang

Full Text Available Identification of important nodes in complex networks has attracted an increasing attention over the last decade. Various measures have been proposed to characterize the importance of nodes in complex networks, such as the degree, betweenness and PageRank. Different measures consider different aspects of complex networks. Although there are numerous results reported on undirected complex networks, few results have been reported on directed biological networks. Based on network motifs and principal component analysis (PCA, this paper aims at introducing a new measure to characterize node importance in directed biological networks. Investigations on five real-world biological networks indicate that the proposed method can robustly identify actually important nodes in different networks, such as finding command interneurons, global regulators and non-hub but evolutionary conserved actually important nodes in biological networks. Receiver Operating Characteristic (ROC curves for the five networks indicate remarkable prediction accuracy of the proposed measure. The proposed index provides an alternative complex network metric. Potential implications of the related investigations include identifying network control and regulation targets, biological networks modeling and analysis, as well as networked medicine.

Functional Module Analysis for Gene Coexpression Networks with Network Integration.

Science.gov (United States)

Zhang, Shuqin; Zhao, Hongyu; Ng, Michael K

2015-01-01

Network has been a general tool for studying the complex interactions between different genes, proteins, and other small molecules. Module as a fundamental property of many biological networks has been widely studied and many computational methods have been proposed to identify the modules in an individual network. However, in many cases, a single network is insufficient for module analysis due to the noise in the data or the tuning of parameters when building the biological network. The availability of a large amount of biological networks makes network integration study possible. By integrating such networks, more informative modules for some specific disease can be derived from the networks constructed from different tissues, and consistent factors for different diseases can be inferred. In this paper, we have developed an effective method for module identification from multiple networks under different conditions. The problem is formulated as an optimization model, which combines the module identification in each individual network and alignment of the modules from different networks together. An approximation algorithm based on eigenvector computation is proposed. Our method outperforms the existing methods, especially when the underlying modules in multiple networks are different in simulation studies. We also applied our method to two groups of gene coexpression networks for humans, which include one for three different cancers, and one for three tissues from the morbidly obese patients. We identified 13 modules with three complete subgraphs, and 11 modules with two complete subgraphs, respectively. The modules were validated through Gene Ontology enrichment and KEGG pathway enrichment analysis. We also showed that the main functions of most modules for the corresponding disease have been addressed by other researchers, which may provide the theoretical basis for further studying the modules experimentally.

Network Analysis Tools: from biological networks to clusters and pathways.

Science.gov (United States)

Brohée, Sylvain; Faust, Karoline; Lima-Mendez, Gipsi; Vanderstocken, Gilles; van Helden, Jacques

2008-01-01

Network Analysis Tools (NeAT) is a suite of computer tools that integrate various algorithms for the analysis of biological networks: comparison between graphs, between clusters, or between graphs and clusters; network randomization; analysis of degree distribution; network-based clustering and path finding. The tools are interconnected to enable a stepwise analysis of the network through a complete analytical workflow. In this protocol, we present a typical case of utilization, where the tasks above are combined to decipher a protein-protein interaction network retrieved from the STRING database. The results returned by NeAT are typically subnetworks, networks enriched with additional information (i.e., clusters or paths) or tables displaying statistics. Typical networks comprising several thousands of nodes and arcs can be analyzed within a few minutes. The complete protocol can be read and executed in approximately 1 h.

Energy-aware virtual network embedding in flexi-grid optical networks

Science.gov (United States)

Lin, Rongping; Luo, Shan; Wang, Haoran; Wang, Sheng; Chen, Bin

2018-01-01

Virtual network embedding (VNE) problem is to map multiple heterogeneous virtual networks (VN) on a shared substrate network, which mitigate the ossification of the substrate network. Meanwhile, energy efficiency has been widely considered in the network design. In this paper, we aim to solve the energy-aware VNE problem in flexi-grid optical networks. We provide an integer linear programming (ILP) formulation to minimize the power increment of each arriving VN request. We also propose a polynomial-time heuristic algorithm where virtual links are embedded sequentially to keep a reasonable acceptance ratio and maintain a low energy consumption. Numerical results show the functionality of the heuristic algorithm in a 24-node network.

Technical Network

CERN Multimedia

2007-01-01

In order to optimise the management of the Technical Network (TN), to facilitate understanding of the purpose of devices connected to the TN and to improve security incident handling, the Technical Network Administrators and the CNIC WG have asked IT/CS to verify the "description" and "tag" fields of devices connected to the TN. Therefore, persons responsible for systems connected to the TN will receive e-mails from IT/CS asking them to add the corresponding information in the network database at "network-cern-ch". Thank you very much for your cooperation. The Technical Network Administrators & the CNIC WG

An examination of a reciprocal relationship between network governance and network structure

DEFF Research Database (Denmark)

Bergenholtz, Carsten; Goduscheit, René Chester

The present article examines the network structure and governance of inter-organisational innovation networks. Network governance refers to the issue of how to manage and coordinate the relational activities and processes in the network while research on network structure deals with the overall...... structural relations between the actors in the network. These streams of research do contain references to each other but mostly rely on a static conception of the relationship between network structure and the applied network governance. The paper is based on a primarily qualitative case study of a loosely...... coupled Danish inter-organisational innovation network. The proposition is that a reciprocal relation between network governance and network structure can be identified....

Statistical Network Analysis for Functional MRI: Mean Networks and Group Comparisons.

Directory of Open Access Journals (Sweden)

Cedric E Ginestet

2014-05-01

Full Text Available Comparing networks in neuroscience is hard, because the topological properties of a given network are necessarily dependent on the number of edges of that network. This problem arises in the analysis of both weighted and unweighted networks. The term density is often used in this context, in order to refer to the mean edge weight of a weighted network, or to the number of edges in an unweighted one. Comparing families of networks is therefore statistically difficult because differences in topology are necessarily associated with differences in density. In this review paper, we consider this problem from two different perspectives, which include (i the construction of summary networks, such as how to compute and visualize the mean network from a sample of network-valued data points; and (ii how to test for topological differences, when two families of networks also exhibit significant differences in density. In the first instance, we show that the issue of summarizing a family of networks can be conducted by either adopting a mass-univariate approach, which produces a statistical parametric network (SPN, or by directly computing the mean network, provided that a metric has been specified on the space of all networks with a given number of nodes. In the second part of this review, we then highlight the inherent problems associated with the comparison of topological functions of families of networks that differ in density. In particular, we show that a wide range of topological summaries, such as global efficiency and network modularity are highly sensitive to differences in density. Moreover, these problems are not restricted to unweighted metrics, as we demonstrate that the same issues remain present when considering the weighted versions of these metrics. We conclude by encouraging caution, when reporting such statistical comparisons, and by emphasizing the importance of constructing summary networks.

Network rewiring dynamics with convergence towards a star network.

Science.gov (United States)

Whigham, P A; Dick, G; Parry, M

2016-10-01

Network rewiring as a method for producing a range of structures was first introduced in 1998 by Watts & Strogatz ( Nature 393 , 440-442. (doi:10.1038/30918)). This approach allowed a transition from regular through small-world to a random network. The subsequent interest in scale-free networks motivated a number of methods for developing rewiring approaches that converged to scale-free networks. This paper presents a rewiring algorithm (RtoS) for undirected, non-degenerate, fixed size networks that transitions from regular, through small-world and scale-free to star-like networks. Applications of the approach to models for the spread of infectious disease and fixation time for a simple genetics model are used to demonstrate the efficacy and application of the approach.

In-Network Adaptation of Video Streams Using Network Processors

Directory of Open Access Journals (Sweden)

Mohammad Shorfuzzaman

2009-01-01

problem can be addressed, near the network edge, by applying dynamic, in-network adaptation (e.g., transcoding of video streams to meet available connection bandwidth, machine characteristics, and client preferences. In this paper, we extrapolate from earlier work of Shorfuzzaman et al. 2006 in which we implemented and assessed an MPEG-1 transcoding system on the Intel IXP1200 network processor to consider the feasibility of in-network transcoding for other video formats and network processor architectures. The use of “on-the-fly” video adaptation near the edge of the network offers the promise of simpler support for a wide range of end devices with different display, and so forth, characteristics that can be used in different types of environments.

Teisel katsel Riias = Second go-round in Riga / Jaak Jõerüüt

Index Scriptorium Estoniae

Jõerüüt, Jaak, 1947-

2008-01-01

Eesti suursaadik Lätis, arhitektuurivõistluse žürii liige Riia Eesti saatkonnahoone arhitektuurikonkursist, võidutöödest. Lk. 56-57 Eesti saatkond Riias: I koha pälvinud Lembit-Kaur Stööri, Ülo-Tarmo Stööri ja Heidi Urbi võidutööst, premeeritud tööde plaanid, vaated. II koha said Emil Urbel, Andrus Mark, Ott Hirvesoo ja Peeter Veimer, III koha Juris Mitenbergs, Peteris Suprins, Zane Krumina, Uldis Tucs, Edgars Gribusts ja Edijs Kravalis

Kibel groups and their dynamic perspective

DEFF Research Database (Denmark)

Heinskou, Torben

2010-01-01

authors look the state of research on therapeutic groupwork in inpatient settings, and suggest how the evidence base might be strengthened. The book will be of great value to any mental health professional, whether qualified or in training. Although reflecting experience in British clinical settings...... Interpersonal Model. Katja Hajek The groupworker as consultant to the group. Adam Jefford, Bhupinderjit Kaur Pharwaha and Alistair Grandison Running structured problem solving groups on acute wards. Susan J. Grey Psychodynamically informed groupwork with patients with psychosis:Challenges for co...

Linlane ei tea, kuidas maal elatakse / Imbi Raikna

Index Scriptorium Estoniae

Raikna, Imbi

2004-01-01

2004. a. märtsis ja aprillis tehtud uurimusest "Põllumajandusministeeriumi ja maaelu imago Eesti linnaelanike seas". Tabelid: Maakohtade külastamise sagedus; Maakohtade külastamise põhjused. Vt. ka: Mida maaelu tundjad arvavad linnaelanike uuringu tulemustest. Kommenteerivad Riigikogu liikmed Imre Sooäär, Jaanus Marrandi ja Mati Kepp, MTÜ Saaremaa Kodukant juht Elvi Viira, MTÜ Kodukant Viljandimaa juht Kaja Kaur, MTÜ Kodukant Tartumaa juht Lea Saul, Saarde vallavalitsuse volikogu esimees Väino Lill ja Lääne-Virumaa Uhtna küla elanik Inge Pikkoja

Analysis of Semantic Networks using Complex Networks Concepts

DEFF Research Database (Denmark)

Ortiz-Arroyo, Daniel

2013-01-01

In this paper we perform a preliminary analysis of semantic networks to determine the most important terms that could be used to optimize a summarization task. In our experiments, we measure how the properties of a semantic network change, when the terms in the network are removed. Our preliminar...

Network survivability performance

Science.gov (United States)

1993-11-01

This technical report has been developed to address the survivability of telecommunications networks including services. It responds to the need for a common understanding of, and assessment techniques for network survivability, availability, integrity, and reliability. It provides a basis for designing and operating telecommunications networks to user expectations for network survivability and a foundation for continuing industry activities in the subject area. This report focuses on the survivability of both public and private networks and covers a wide range of users. Two frameworks are established for quantifying and categorizing service outages, and for classifying network survivability techniques and measures. The performance of the network survivability techniques is considered; however, recommended objectives are not established for network survivability performance.

Networks and network analysis for defence and security

CERN Document Server

Masys, Anthony J

2014-01-01

Networks and Network Analysis for Defence and Security discusses relevant theoretical frameworks and applications of network analysis in support of the defence and security domains. This book details real world applications of network analysis to support defence and security. Shocks to regional, national and global systems stemming from natural hazards, acts of armed violence, terrorism and serious and organized crime have significant defence and security implications. Today, nations face an uncertain and complex security landscape in which threats impact/target the physical, social, economic

Network analysis literacy a practical approach to the analysis of networks

CERN Document Server

Zweig, Katharina A

2014-01-01

Network Analysis Literacy focuses on design principles for network analytics projects. The text enables readers to: pose a defined network analytic question; build a network to answer the question; choose or design the right network analytic methods for a particular purpose, and more.

Network-Embedded Management and Applications Understanding Programmable Networking Infrastructure

CERN Document Server

Wolter, Ralf

2013-01-01

Despite the explosion of networking services and applications in the past decades, the basic technological underpinnings of the Internet have remained largely unchanged. At its heart are special-purpose appliances that connect us to the digital world, commonly known as switches and routers. Now, however, the traditional framework is being increasingly challenged by new methods that are jostling for a position in the next-generation Internet. The concept of a network that is becoming more programmable is one of the aspects that are taking center stage. This opens new possibilities to embed software applications inside the network itself and to manage networks and communications services with unprecedented ease and efficiency. In this edited volume, distinguished experts take the reader on a tour of different facets of programmable network infrastructure and application exploit it. Presenting the state of the art in network embedded management and applications and programmable network infrastructure, the book c...

Virtualized cognitive network architecture for 5G cellular networks

KAUST Repository

Elsawy, Hesham

2015-07-17

Cellular networks have preserved an application agnostic and base station (BS) centric architecture1 for decades. Network functionalities (e.g. user association) are decided and performed regardless of the underlying application (e.g. automation, tactile Internet, online gaming, multimedia). Such an ossified architecture imposes several hurdles against achieving the ambitious metrics of next generation cellular systems. This article first highlights the features and drawbacks of such architectural ossification. Then the article proposes a virtualized and cognitive network architecture, wherein network functionalities are implemented via software instances in the cloud, and the underlying architecture can adapt to the application of interest as well as to changes in channels and traffic conditions. The adaptation is done in terms of the network topology by manipulating connectivities and steering traffic via different paths, so as to attain the applications\\' requirements and network design objectives. The article presents cognitive strategies to implement some of the classical network functionalities, along with their related implementation challenges. The article further presents a case study illustrating the performance improvement of the proposed architecture as compared to conventional cellular networks, both in terms of outage probability and handover rate.

The entire network topology display system of terminal communication access network

OpenAIRE

An Yi

2016-01-01

Now order terminal communication access network is network technology in Shanxi Province is diversiform, device type complex, lack of unified technical standard, the terminal communication access network management system of construction constitutes a great obstacle. Need to build a “unified communication interface and communication standard, unified communications network management” of the terminal communication access network cut in the integrated network management system, for the termina...

Network function virtualization concepts and applicability in 5G networks

CERN Document Server

Zhang, Ying

2018-01-01

A horizontal view of newly emerged technologies in the field of network function virtualization (NFV), introducing the open source implementation efforts that bring NFV from design to reality This book explores the newly emerged technique of network function virtualization (NFV) through use cases, architecture, and challenges, as well as standardization and open source implementations. It is the first systematic source of information about cloud technologies' usage in the cellular network, covering the interplay of different technologies, the discussion of different design choices, and its impact on our future cellular network. Network Function Virtualization: Concepts and Applicability in 5G Networks reviews new technologies that enable NFV, such as Software Defined Networks (SDN), network virtualization, and cloud computing. It also provides an in-depth investigation of the most advanced open source initiatives in this area, including OPNFV, Openstack, and Opendaylight. Finally, this book goes beyond li...

A Squeezed Artificial Neural Network for the Symbolic Network Reliability Functions of Binary-State Networks.

Science.gov (United States)

Yeh, Wei-Chang

Network reliability is an important index to the provision of useful information for decision support in the modern world. There is always a need to calculate symbolic network reliability functions (SNRFs) due to dynamic and rapid changes in network parameters. In this brief, the proposed squeezed artificial neural network (SqANN) approach uses the Monte Carlo simulation to estimate the corresponding reliability of a given designed matrix from the Box-Behnken design, and then the Taguchi method is implemented to find the appropriate number of neurons and activation functions of the hidden layer and the output layer in ANN to evaluate SNRFs. According to the experimental results of the benchmark networks, the comparison appears to support the superiority of the proposed SqANN method over the traditional ANN-based approach with at least 16.6% improvement in the median absolute deviation in the cost of extra 2 s on average for all experiments.Network reliability is an important index to the provision of useful information for decision support in the modern world. There is always a need to calculate symbolic network reliability functions (SNRFs) due to dynamic and rapid changes in network parameters. In this brief, the proposed squeezed artificial neural network (SqANN) approach uses the Monte Carlo simulation to estimate the corresponding reliability of a given designed matrix from the Box-Behnken design, and then the Taguchi method is implemented to find the appropriate number of neurons and activation functions of the hidden layer and the output layer in ANN to evaluate SNRFs. According to the experimental results of the benchmark networks, the comparison appears to support the superiority of the proposed SqANN method over the traditional ANN-based approach with at least 16.6% improvement in the median absolute deviation in the cost of extra 2 s on average for all experiments.

Low Computational Complexity Network Coding For Mobile Networks

DEFF Research Database (Denmark)

Heide, Janus

2012-01-01

Network Coding (NC) is a technique that can provide benefits in many types of networks, some examples from wireless networks are: In relay networks, either the physical or the data link layer, to reduce the number of transmissions. In reliable multicast, to reduce the amount of signaling and enable......-flow coding technique. One of the key challenges of this technique is its inherent computational complexity which can lead to high computational load and energy consumption in particular on the mobile platforms that are the target platform in this work. To increase the coding throughput several...

Computer network time synchronization the network time protocol

CERN Document Server

Mills, David L

2006-01-01

What started with the sundial has, thus far, been refined to a level of precision based on atomic resonance: Time. Our obsession with time is evident in this continued scaling down to nanosecond resolution and beyond. But this obsession is not without warrant. Precision and time synchronization are critical in many applications, such as air traffic control and stock trading, and pose complex and important challenges in modern information networks.Penned by David L. Mills, the original developer of the Network Time Protocol (NTP), Computer Network Time Synchronization: The Network Time Protocol

Resilience of networks formed of interdependent modular networks

Science.gov (United States)

Shekhtman, Louis M.; Shai, Saray; Havlin, Shlomo

2015-12-01

Many infrastructure networks have a modular structure and are also interdependent with other infrastructures. While significant research has explored the resilience of interdependent networks, there has been no analysis of the effects of modularity. Here we develop a theoretical framework for attacks on interdependent modular networks and support our results through simulations. We focus, for simplicity, on the case where each network has the same number of communities and the dependency links are restricted to be between pairs of communities of different networks. This is particularly realistic for modeling infrastructure across cities. Each city has its own infrastructures and different infrastructures are dependent only within the city. However, each infrastructure is connected within and between cities. For example, a power grid will connect many cities as will a communication network, yet a power station and communication tower that are interdependent will likely be in the same city. It has previously been shown that single networks are very susceptible to the failure of the interconnected nodes (between communities) (Shai et al 2014 arXiv:1404.4748) and that attacks on these nodes are even more crippling than attacks based on betweenness (da Cunha et al 2015 arXiv:1502.00353). In our example of cities these nodes have long range links which are more likely to fail. For both treelike and looplike interdependent modular networks we find distinct regimes depending on the number of modules, m. (i) In the case where there are fewer modules with strong intraconnections, the system first separates into modules in an abrupt first-order transition and then each module undergoes a second percolation transition. (ii) When there are more modules with many interconnections between them, the system undergoes a single transition. Overall, we find that modular structure can significantly influence the type of transitions observed in interdependent networks and should be

A Network of Networks Perspective on Global Trade

Science.gov (United States)

Maluck, Julian; Donner, Reik V.

2015-01-01

Mutually intertwined supply chains in contemporary economy result in a complex network of trade relationships with a highly non-trivial topology that varies with time. In order to understand the complex interrelationships among different countries and economic sectors, as well as their dynamics, a holistic view on the underlying structural properties of this network is necessary. This study employs multi-regional input-output data to decompose 186 national economies into 26 industry sectors and utilizes the approach of interdependent networks to analyze the substructure of the resulting international trade network for the years 1990–2011. The partition of the network into national economies is observed to be compatible with the notion of communities in the sense of complex network theory. By studying internal versus cross-subgraph contributions to established complex network metrics, new insights into the architecture of global trade are obtained, which allow to identify key elements of global economy. Specifically, financial services and business activities dominate domestic trade whereas electrical and machinery industries dominate foreign trade. In order to further specify each national sector’s role individually, (cross-)clustering coefficients and cross-betweenness are obtained for different pairs of subgraphs. The corresponding analysis reveals that specific industrial sectors tend to favor distinct directionality patterns and that the cross-clustering coefficient for geographically close country pairs is remarkably high, indicating that spatial factors are still of paramount importance for the organization of trade patterns in modern economy. Regarding the evolution of the trade network’s substructure, globalization is well-expressed by trends of several structural characteristics (e.g., link density and node strength) in the interacting network framework. Extreme events, such as the financial crisis 2008/2009, are manifested as anomalies superimposed

Dominating biological networks.

Directory of Open Access Journals (Sweden)

Tijana Milenković

Full Text Available Proteins are essential macromolecules of life that carry out most cellular processes. Since proteins aggregate to perform function, and since protein-protein interaction (PPI networks model these aggregations, one would expect to uncover new biology from PPI network topology. Hence, using PPI networks to predict protein function and role of protein pathways in disease has received attention. A debate remains open about whether network properties of "biologically central (BC" genes (i.e., their protein products, such as those involved in aging, cancer, infectious diseases, or signaling and drug-targeted pathways, exhibit some topological centrality compared to the rest of the proteins in the human PPI network.To help resolve this debate, we design new network-based approaches and apply them to get new insight into biological function and disease. We hypothesize that BC genes have a topologically central (TC role in the human PPI network. We propose two different concepts of topological centrality. We design a new centrality measure to capture complex wirings of proteins in the network that identifies as TC those proteins that reside in dense extended network neighborhoods. Also, we use the notion of domination and find dominating sets (DSs in the PPI network, i.e., sets of proteins such that every protein is either in the DS or is a neighbor of the DS. Clearly, a DS has a TC role, as it enables efficient communication between different network parts. We find statistically significant enrichment in BC genes of TC nodes and outperform the existing methods indicating that genes involved in key biological processes occupy topologically complex and dense regions of the network and correspond to its "spine" that connects all other network parts and can thus pass cellular signals efficiently throughout the network. To our knowledge, this is the first study that explores domination in the context of PPI networks.

SCM: A method to improve network service layout efficiency with network evolution

Science.gov (United States)

Zhao, Qi; Zhang, Chuanhao

2017-01-01

Network services are an important component of the Internet, which are used to expand network functions for third-party developers. Network function virtualization (NFV) can improve the speed and flexibility of network service deployment. However, with the evolution of the network, network service layout may become inefficient. Regarding this problem, this paper proposes a service chain migration (SCM) method with the framework of “software defined network + network function virtualization” (SDN+NFV), which migrates service chains to adapt to network evolution and improves the efficiency of the network service layout. SCM is modeled as an integer linear programming problem and resolved via particle swarm optimization. An SCM prototype system is designed based on an SDN controller. Experiments demonstrate that SCM could reduce the network traffic cost and energy consumption efficiently. PMID:29267299

SCM: A method to improve network service layout efficiency with network evolution.

Science.gov (United States)

Zhao, Qi; Zhang, Chuanhao; Zhao, Zheng

2017-01-01

Network services are an important component of the Internet, which are used to expand network functions for third-party developers. Network function virtualization (NFV) can improve the speed and flexibility of network service deployment. However, with the evolution of the network, network service layout may become inefficient. Regarding this problem, this paper proposes a service chain migration (SCM) method with the framework of "software defined network + network function virtualization" (SDN+NFV), which migrates service chains to adapt to network evolution and improves the efficiency of the network service layout. SCM is modeled as an integer linear programming problem and resolved via particle swarm optimization. An SCM prototype system is designed based on an SDN controller. Experiments demonstrate that SCM could reduce the network traffic cost and energy consumption efficiently.

Allocating resources between network nodes for providing a network node function

NARCIS (Netherlands)

Strijkers, R.J.; Meulenhoff, P.J.

2014-01-01

The invention provides a method wherein a first network node advertises available resources that a second network node may use to offload network node functions transparently to the first network node. Examples of the first network node are a client device (e.g. PC, notebook, tablet, smart phone), a

Multilayer Brain Networks

Science.gov (United States)

Vaiana, Michael; Muldoon, Sarah Feldt

2018-01-01

The field of neuroscience is facing an unprecedented expanse in the volume and diversity of available data. Traditionally, network models have provided key insights into the structure and function of the brain. With the advent of big data in neuroscience, both more sophisticated models capable of characterizing the increasing complexity of the data and novel methods of quantitative analysis are needed. Recently, multilayer networks, a mathematical extension of traditional networks, have gained increasing popularity in neuroscience due to their ability to capture the full information of multi-model, multi-scale, spatiotemporal data sets. Here, we review multilayer networks and their applications in neuroscience, showing how incorporating the multilayer framework into network neuroscience analysis has uncovered previously hidden features of brain networks. We specifically highlight the use of multilayer networks to model disease, structure-function relationships, network evolution, and link multi-scale data. Finally, we close with a discussion of promising new directions of multilayer network neuroscience research and propose a modified definition of multilayer networks designed to unite and clarify the use of the multilayer formalism in describing real-world systems.

Collaborative Multi-Layer Network Coding in Hybrid Cellular Cognitive Radio Networks

KAUST Repository

Moubayed, Abdallah J.

2015-05-01

In this paper, as an extension to [1], we propose a prioritized multi-layer network coding scheme for collaborative packet recovery in hybrid (interweave and underlay) cellular cognitive radio networks. This scheme allows the uncoordinated collaboration between the collocated primary and cognitive radio base-stations in order to minimize their own as well as each other\\'s packet recovery overheads, thus by improving their throughput. The proposed scheme ensures that each network\\'s performance is not degraded by its help to the other network. Moreover, it guarantees that the primary network\\'s interference threshold is not violated in the same and adjacent cells. Yet, the scheme allows the reduction of the recovery overhead in the collocated primary and cognitive radio networks. The reduction in the cognitive radio network is further amplified due to the perfect detection of spectrum holes which allows the cognitive radio base station to transmit at higher power without fear of violating the interference threshold of the primary network. For the secondary network, simulation results show reductions of 20% and 34% in the packet recovery overhead, compared to the non-collaborative scheme, for low and high probabilities of primary packet arrivals, respectively. For the primary network, this reduction was found to be 12%. © 2015 IEEE.

Optical network control plane for multi-domain networking

DEFF Research Database (Denmark)

Manolova, Anna Vasileva

This thesis focuses on multi-domain routing for traffice engineering and survivability support in optical transport networks under the Generalized Multi-Protocol Label Switching (GMPLS) control framework. First, different extensions to the Border Gateway Protocol for multi-domain Traffic...... process are not enough for efficient TE in mesh multi-domain networks. Enhancing the protocol with multi-path dissemination capability, combined with the employment of an end-to-end TE metric proves to be a highly efficient solution. Simulation results show good performance characteristics of the proposed...... is not as essential for improved network performance as the length of the provided paths. Second, the issue of multi-domain survivability support is analyzed. An AS-disjoint paths is beneficial not only for resilience support, but also for facilitating adequate network reactions to changes in the network, which...

Resilience of networks to environmental stress: From regular to random networks

Science.gov (United States)

Eom, Young-Ho

2018-04-01

Despite the huge interest in network resilience to stress, most of the studies have concentrated on internal stress damaging network structure (e.g., node removals). Here we study how networks respond to environmental stress deteriorating their external conditions. We show that, when regular networks gradually disintegrate as environmental stress increases, disordered networks can suddenly collapse at critical stress with hysteresis and vulnerability to perturbations. We demonstrate that this difference results from a trade-off between node resilience and network resilience to environmental stress. The nodes in the disordered networks can suppress their collapses due to the small-world topology of the networks but eventually collapse all together in return. Our findings indicate that some real networks can be highly resilient against environmental stress to a threshold yet extremely vulnerable to the stress above the threshold because of their small-world topology.

Introductory note on Emergent Unconscious Knowledge Networks (Asygnodic Networks

Directory of Open Access Journals (Sweden)

Henry Bakis

2016-05-01

Full Text Available This note introduces the following paper on the concept of Emergent Unconscious Knowledge Networks (Asygnodic Networks created by E. Roche and M. Blaine. The concept of asyngnosis explains a large number of diverse phenomena involving organizations, groups and decision making. It will present the genesis and definition of Asygnodic Networks and will focus on how they raise challenges to traditional theories of decision making and emerging social networks.

Maximization Network Throughput Based on Improved Genetic Algorithm and Network Coding for Optical Multicast Networks

Science.gov (United States)

Wei, Chengying; Xiong, Cuilian; Liu, Huanlin

2017-12-01

Maximal multicast stream algorithm based on network coding (NC) can improve the network's throughput for wavelength-division multiplexing (WDM) networks, which however is far less than the network's maximal throughput in terms of theory. And the existing multicast stream algorithms do not give the information distribution pattern and routing in the meantime. In the paper, an improved genetic algorithm is brought forward to maximize the optical multicast throughput by NC and to determine the multicast stream distribution by hybrid chromosomes construction for multicast with single source and multiple destinations. The proposed hybrid chromosomes are constructed by the binary chromosomes and integer chromosomes, while the binary chromosomes represent optical multicast routing and the integer chromosomes indicate the multicast stream distribution. A fitness function is designed to guarantee that each destination can receive the maximum number of decoding multicast streams. The simulation results showed that the proposed method is far superior over the typical maximal multicast stream algorithms based on NC in terms of network throughput in WDM networks.

The network researchers' network

DEFF Research Database (Denmark)

Henneberg, Stephan C.; Jiang, Zhizhong; Naudé, Peter

2009-01-01

The Industrial Marketing and Purchasing (IMP) Group is a network of academic researchers working in the area of business-to-business marketing. The group meets every year to discuss and exchange ideas, with a conference having been held every year since 1984 (there was no meeting in 1987). In thi......The Industrial Marketing and Purchasing (IMP) Group is a network of academic researchers working in the area of business-to-business marketing. The group meets every year to discuss and exchange ideas, with a conference having been held every year since 1984 (there was no meeting in 1987......). In this paper, based upon the papers presented at the 22 conferences held to date, we undertake a Social Network Analysis in order to examine the degree of co-publishing that has taken place between this group of researchers. We identify the different components in this database, and examine the large main...

Managerial Challenges Within Networks - Emphasizing the Paradox of Network Participation

DEFF Research Database (Denmark)

Jakobsen, Morten

2003-01-01

Flexibility and access to numerous resources are essential benefits associated with network participation. An important aspect of managing the network participation of a company is to maintain a dynamic portfolio of partners, and thereby keep up the strategic opportunities for development. However......, maintaining the dynamics within a network seems to be a complex challenge. There is a risk that the network ends up in The Paradox of Network Participation. The desired renewal and flexibility are not utilised because the involved parties preserve the existing networks structure consisting of the same...... and thereby sort out the paradox of network participation. Trust and information are mechanisms employed to absorb uncertainty. The relationship between trust and the requirement for information depends on the maturity of the relationship. When trust becomes too important as uncertainty absorption mechanism...

Managerial challenges within networks: emphasizing the paradox of network participation

DEFF Research Database (Denmark)

Jakobsen, Morten

Flexibility and access to numerous resources are essential benefits associated with network participation. An important aspect of managing the network participation of a company is to maintain a dynamic portfolio of partners, and thereby keep up the strategic opportunities for development. However......, maintaining the dynamics within a network seems to be a complex challenge. There is a risk that the network ends up in The Paradox of Network Participation. The desired renewal and flexibility are not utilised because the involved parties preserve the existing networks structure consisting of the same...... and thereby sort out the paradox of network participation. Trust and information are mechanisms employed to absorb uncertainty. The relationship between trust and the requirement for information depends on the maturity of the relationship. When trust becomes too important as uncertainty absorption mechanism...

Energy Efficient Network Protocols for Wireless and Mobile Networks

National Research Council Canada - National Science Library

Sivalingam, Krishna

2001-01-01

... (also called power aware) network protocols for wireless and mobile networks. Battery power limitations are a very serious concern, and it is essential to study energy efficient protocol design at different layers of the network protocol stack...

Temporal network epidemiology

CERN Document Server

Holme, Petter

2017-01-01

This book covers recent developments in epidemic process models and related data on temporally varying networks. It is widely recognized that contact networks are indispensable for describing, understanding, and intervening to stop the spread of infectious diseases in human and animal populations; “network epidemiology” is an umbrella term to describe this research field. More recently, contact networks have been recognized as being highly dynamic. This observation, also supported by an increasing amount of new data, has led to research on temporal networks, a rapidly growing area. Changes in network structure are often informed by epidemic (or other) dynamics, in which case they are referred to as adaptive networks. This volume gathers contributions by prominent authors working in temporal and adaptive network epidemiology, a field essential to understanding infectious diseases in real society.

Collaborative multi-layer network coding for cellular cognitive radio networks

KAUST Repository

Sorour, Sameh

2013-06-01

In this paper, we propose a prioritized multi-layer network coding scheme for collaborative packet recovery in underlay cellular cognitive radio networks. This scheme allows the collocated primary and cognitive radio base-stations to collaborate with each other, in order to minimize their own and each other\\'s packet recovery overheads, and thus improve their throughput, without any coordination between them. This non-coordinated collaboration is done using a novel multi-layer instantly decodable network coding scheme, which guarantees that each network\\'s help to the other network does not result in any degradation in its own performance. It also does not cause any violation to the primary networks interference thresholds in the same and adjacent cells. Yet, our proposed scheme both guarantees the reduction of the recovery overhead in collocated primary and cognitive radio networks, and allows early recovery of their packets compared to non-collaborative schemes. Simulation results show that a recovery overhead reduction of 15% and 40% can be achieved by our proposed scheme in the primary and cognitive radio networks, respectively, compared to the corresponding non-collaborative scheme. © 2013 IEEE.

Network Simulation

CERN Document Server

Fujimoto, Richard

2006-01-01

"Network Simulation" presents a detailed introduction to the design, implementation, and use of network simulation tools. Discussion topics include the requirements and issues faced for simulator design and use in wired networks, wireless networks, distributed simulation environments, and fluid model abstractions. Several existing simulations are given as examples, with details regarding design decisions and why those decisions were made. Issues regarding performance and scalability are discussed in detail, describing how one can utilize distributed simulation methods to increase the

Morphological neural networks

Energy Technology Data Exchange (ETDEWEB)

Ritter, G.X.; Sussner, P. [Univ. of Florida, Gainesville, FL (United States)

1996-12-31

The theory of artificial neural networks has been successfully applied to a wide variety of pattern recognition problems. In this theory, the first step in computing the next state of a neuron or in performing the next layer neural network computation involves the linear operation of multiplying neural values by their synaptic strengths and adding the results. Thresholding usually follows the linear operation in order to provide for nonlinearity of the network. In this paper we introduce a novel class of neural networks, called morphological neural networks, in which the operations of multiplication and addition are replaced by addition and maximum (or minimum), respectively. By taking the maximum (or minimum) of sums instead of the sum of products, morphological network computation is nonlinear before thresholding. As a consequence, the properties of morphological neural networks are drastically different than those of traditional neural network models. In this paper we consider some of these differences and provide some particular examples of morphological neural network.

Directed network modules

International Nuclear Information System (INIS)

Palla, Gergely; Farkas, Illes J; Pollner, Peter; Derenyi, Imre; Vicsek, Tamas

2007-01-01

A search technique locating network modules, i.e. internally densely connected groups of nodes in directed networks is introduced by extending the clique percolation method originally proposed for undirected networks. After giving a suitable definition for directed modules we investigate their percolation transition in the Erdos-Renyi graph both analytically and numerically. We also analyse four real-world directed networks, including Google's own web-pages, an email network, a word association graph and the transcriptional regulatory network of the yeast Saccharomyces cerevisiae. The obtained directed modules are validated by additional information available for the nodes. We find that directed modules of real-world graphs inherently overlap and the investigated networks can be classified into two major groups in terms of the overlaps between the modules. Accordingly, in the word-association network and Google's web-pages, overlaps are likely to contain in-hubs, whereas the modules in the email and transcriptional regulatory network tend to overlap via out-hubs

Network connectivity value.

Science.gov (United States)

Dragicevic, Arnaud; Boulanger, Vincent; Bruciamacchie, Max; Chauchard, Sandrine; Dupouey, Jean-Luc; Stenger, Anne

2017-04-21

In order to unveil the value of network connectivity, we formalize the construction of ecological networks in forest environments as an optimal control dynamic graph-theoretic problem. The network is based on a set of bioreserves and patches linked by ecological corridors. The node dynamics, built upon the consensus protocol, form a time evolutive Mahalanobis distance weighted by the opportunity costs of timber production. We consider a case of complete graph, where the ecological network is fully connected, and a case of incomplete graph, where the ecological network is partially connected. The results show that the network equilibrium depends on the size of the reception zone, while the network connectivity depends on the environmental compatibility between the ecological areas. Through shadow prices, we find that securing connectivity in partially connected networks is more expensive than in fully connected networks, but should be undertaken when the opportunity costs are significant. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tunable Sparse Network Coding for Multicast Networks

DEFF Research Database (Denmark)

Feizi, Soheil; Roetter, Daniel Enrique Lucani; Sørensen, Chres Wiant

2014-01-01

This paper shows the potential and key enabling mechanisms for tunable sparse network coding, a scheme in which the density of network coded packets varies during a transmission session. At the beginning of a transmission session, sparsely coded packets are transmitted, which benefits decoding...... complexity. At the end of a transmission, when receivers have accumulated degrees of freedom, coding density is increased. We propose a family of tunable sparse network codes (TSNCs) for multicast erasure networks with a controllable trade-off between completion time performance to decoding complexity...... a mechanism to perform efficient Gaussian elimination over sparse matrices going beyond belief propagation but maintaining low decoding complexity. Supporting simulation results are provided showing the trade-off between decoding complexity and completion time....

A COMPARATIVE STUDY OF SYSTEM NETWORK ARCHITECTURE Vs DIGITAL NETWORK ARCHITECTURE

OpenAIRE

Seema; Mukesh Arya

2011-01-01

The efficient managing system of sources is mandatory for the successful running of any network. Here this paper describes the most popular network architectures one of developed by IBM, System Network Architecture (SNA) and other is Digital Network Architecture (DNA). As we know that the network standards and protocols are needed for the network developers as well as users. Some standards are The IEEE 802.3 standards (The Institute of Electrical and Electronics Engineers 1980) (LAN), IBM Sta...

A research on the application of software defined networking in satellite network architecture

Science.gov (United States)

Song, Huan; Chen, Jinqiang; Cao, Suzhi; Cui, Dandan; Li, Tong; Su, Yuxing

2017-10-01

Software defined network is a new type of network architecture, which decouples control plane and data plane of traditional network, has the feature of flexible configurations and is a direction of the next generation terrestrial Internet development. Satellite network is an important part of the space-ground integrated information network, while the traditional satellite network has the disadvantages of difficult network topology maintenance and slow configuration. The application of SDN technology in satellite network can solve these problems that traditional satellite network faces. At present, the research on the application of SDN technology in satellite network is still in the stage of preliminary study. In this paper, we start with introducing the SDN technology and satellite network architecture. Then we mainly introduce software defined satellite network architecture, as well as the comparison of different software defined satellite network architecture and satellite network virtualization. Finally, the present research status and development trend of SDN technology in satellite network are analyzed.

Opportunistic Beacon Networks: Information Dissemination via Wireless Network Identifiers

NARCIS (Netherlands)

Türkes, Okan; Scholten, Johan; Havinga, Paul J.M.

2016-01-01

This paper presents OBN, a universal opportunistic ad hoc networking model particularly intended for smart mobile devices. It enables fast and lightweight data dissemination in wireless community networks through the utilization of universally-available wireless network identifiers. As a ubiquitous

CUFID-query: accurate network querying through random walk based network flow estimation.

Science.gov (United States)

Jeong, Hyundoo; Qian, Xiaoning; Yoon, Byung-Jun

2017-12-28

Functional modules in biological networks consist of numerous biomolecules and their complicated interactions. Recent studies have shown that biomolecules in a functional module tend to have similar interaction patterns and that such modules are often conserved across biological networks of different species. As a result, such conserved functional modules can be identified through comparative analysis of biological networks. In this work, we propose a novel network querying algorithm based on the CUFID (Comparative network analysis Using the steady-state network Flow to IDentify orthologous proteins) framework combined with an efficient seed-and-extension approach. The proposed algorithm, CUFID-query, can accurately detect conserved functional modules as small subnetworks in the target network that are expected to perform similar functions to the given query functional module. The CUFID framework was recently developed for probabilistic pairwise global comparison of biological networks, and it has been applied to pairwise global network alignment, where the framework was shown to yield accurate network alignment results. In the proposed CUFID-query algorithm, we adopt the CUFID framework and extend it for local network alignment, specifically to solve network querying problems. First, in the seed selection phase, the proposed method utilizes the CUFID framework to compare the query and the target networks and to predict the probabilistic node-to-node correspondence between the networks. Next, the algorithm selects and greedily extends the seed in the target network by iteratively adding nodes that have frequent interactions with other nodes in the seed network, in a way that the conductance of the extended network is maximally reduced. Finally, CUFID-query removes irrelevant nodes from the querying results based on the personalized PageRank vector for the induced network that includes the fully extended network and its neighboring nodes. Through extensive

A random network based, node attraction facilitated network evolution method

Directory of Open Access Journals (Sweden)

WenJun Zhang

2016-03-01

Full Text Available In present study, I present a method of network evolution that based on random network, and facilitated by node attraction. In this method, I assume that the initial network is a random network, or a given initial network. When a node is ready to connect, it tends to link to the node already owning the most connections, which coincides with the general rule (Barabasi and Albert, 1999 of node connecting. In addition, a node may randomly disconnect a connection i.e., the addition of connections in the network is accompanied by the pruning of some connections. The dynamics of network evolution is determined of the attraction factor Lamda of nodes, the probability of node connection, the probability of node disconnection, and the expected initial connectance. The attraction factor of nodes, the probability of node connection, and the probability of node disconnection are time and node varying. Various dynamics can be achieved by adjusting these parameters. Effects of simplified parameters on network evolution are analyzed. The changes of attraction factor Lamda can reflect various effects of the node degree on connection mechanism. Even the changes of Lamda only will generate various networks from the random to the complex. Therefore, the present algorithm can be treated as a general model for network evolution. Modeling results show that to generate a power-law type of network, the likelihood of a node attracting connections is dependent upon the power function of the node's degree with a higher-order power. Matlab codes for simplified version of the method are provided.

Six heads of origin of sternocleidomastoid muscle: a rare case | Kaur ...

African Journals Online (AJOL)

A morphological variation in the origin of the right sternocleidomastoid muscle was encountered during routine dissection of the neck for undergraduate students. We found six heads of the sternocleidomastoid muscle, two sternal and four clavicular heads. The two sternal heads were lying side by side, while two clavicular ...

NYYD-festivali peakülaline on Mark-Anthony Turnage / Kaur Garshnek

Index Scriptorium Estoniae

Garšnek, Kaur, 1983-

2007-01-01

20. oktoobril Estonia kontserdisaalis toimuvast briti helilooja teose ettekandest. 21. oktoobril toimuvast festivali lõppkontserdist Estonia kontserdisaalis, kus ettekandele tuleb Helena Tulve pala "Extinction des chses vues"

Network security

CERN Document Server

Perez, André

2014-01-01

This book introduces the security mechanisms deployed in Ethernet, Wireless-Fidelity (Wi-Fi), Internet Protocol (IP) and MultiProtocol Label Switching (MPLS) networks. These mechanisms are grouped throughout the book according to the following four functions: data protection, access control, network isolation, and data monitoring. Data protection is supplied by data confidentiality and integrity control services. Access control is provided by a third-party authentication service. Network isolation is supplied by the Virtual Private Network (VPN) service. Data monitoring consists of applying

Heterogeneous network architectures

DEFF Research Database (Denmark)

Christiansen, Henrik Lehrmann

2006-01-01

is flexibility. This thesis investigates such heterogeneous network architectures and how to make them flexible. A survey of algorithms for network design is presented, and it is described how using heuristics can increase the speed. A hierarchical, MPLS based network architecture is described......Future networks will be heterogeneous! Due to the sheer size of networks (e.g., the Internet) upgrades cannot be instantaneous and thus heterogeneity appears. This means that instead of trying to find the olution, networks hould be designed as being heterogeneous. One of the key equirements here...... and it is discussed that it is advantageous to heterogeneous networks and illustrated by a number of examples. Modeling and simulation is a well-known way of doing performance evaluation. An approach to event-driven simulation of communication networks is presented and mixed complexity modeling, which can simplify...

Network Traffic Features for Anomaly Detection in Specific Industrial Control System Network

Directory of Open Access Journals (Sweden)

Matti Mantere

2013-09-01

Full Text Available The deterministic and restricted nature of industrial control system networks sets them apart from more open networks, such as local area networks in office environments. This improves the usability of network security, monitoring approaches that would be less feasible in more open environments. One of such approaches is machine learning based anomaly detection. Without proper customization for the special requirements of the industrial control system network environment, many existing anomaly or misuse detection systems will perform sub-optimally. A machine learning based approach could reduce the amount of manual customization required for different industrial control system networks. In this paper we analyze a possible set of features to be used in a machine learning based anomaly detection system in the real world industrial control system network environment under investigation. The network under investigation is represented by architectural drawing and results derived from network trace analysis. The network trace is captured from a live running industrial process control network and includes both control data and the data flowing between the control network and the office network. We limit the investigation to the IP traffic in the traces.

Allocating resources between network nodes for providing a network node function

OpenAIRE

Strijkers, R.J.; Meulenhoff, P.J.

2014-01-01

The invention provides a method wherein a first network node advertises available resources that a second network node may use to offload network node functions transparently to the first network node. Examples of the first network node are a client device (e.g. PC, notebook, tablet, smart phone), a server (e.g. application server, a proxy server, cloud location, router). Examples of the second network node are an application server, a cloud location or a router. The available resources may b...

Tinnitus: Network pathophysiology-network pharmacology

Directory of Open Access Journals (Sweden)

Ana Belen eElgoyhen

2012-01-01

Full Text Available Tinnitus, the phantom perception of sound, is a prevalent disorder. One in 10 adults has clinically significant subjective tinnitus, and for 1 in 100, tinnitus severely affects their quality of life. Despite the significant unmet clinical need for a safe and effective drug targeting tinnitus relief, there is currently not a single FDA-approved drug on the market. The search for drugs that target tinnitus is hampered by the lack of a deep knowledge of the underlying neural substrates of this pathology. Recent studies are increasingly demonstrating that, as described for other central nervous system disorders, tinnitus is a pathology of brain networks. The application of graph theoretical analysis to brain networks has recently provided new information concerning their topology, their robustness and their vulnerability to attacks. Moreover, the philosophy behind drug design and pharmacotherapy in central nervous system pathologies is changing from that of magic bullets that target individual chemoreceptors or disease-causing genes into that of magic shotguns, promiscuous or dirty drugs that target disease-causing networks, also known as network pharmacology. In the present work we provide some insight into how this knowledge could be applied to tinnitus pathophysiology and pharmacotherapy.

Tinnitus: network pathophysiology-network pharmacology.

Science.gov (United States)

Elgoyhen, Ana B; Langguth, Berthold; Vanneste, Sven; De Ridder, Dirk

2012-01-01

Tinnitus, the phantom perception of sound, is a prevalent disorder. One in 10 adults has clinically significant subjective tinnitus, and for one in 100, tinnitus severely affects their quality of life. Despite the significant unmet clinical need for a safe and effective drug targeting tinnitus relief, there is currently not a single Food and Drug Administration (FDA)-approved drug on the market. The search for drugs that target tinnitus is hampered by the lack of a deep knowledge of the underlying neural substrates of this pathology. Recent studies are increasingly demonstrating that, as described for other central nervous system (CNS) disorders, tinnitus is a pathology of brain networks. The application of graph theoretical analysis to brain networks has recently provided new information concerning their topology, their robustness and their vulnerability to attacks. Moreover, the philosophy behind drug design and pharmacotherapy in CNS pathologies is changing from that of "magic bullets" that target individual chemoreceptors or "disease-causing genes" into that of "magic shotguns," "promiscuous" or "dirty drugs" that target "disease-causing networks," also known as network pharmacology. In the present work we provide some insight into how this knowledge could be applied to tinnitus pathophysiology and pharmacotherapy.

Cisco networking essentials

CERN Document Server

McMillan, Troy

2015-01-01

Start a career in networking Cisco Networking Essentials, 2nd Edition provides the latest for those beginning a career in networking. This book provides the fundamentals of networking and leads you through the concepts, processes, and skills you need to master fundamental networking concepts. Thinking of taking the CCENT Cisco Certified Entry Networking Technician ICND1 Exam 100-101? This book has you covered! With coverage of important topics and objectives, each chapter outlines main points and provides clear, engaging discussion that will give you a sound understanding of core topics and c

Adverse Outcome Pathway Networks II: Network Analytics.

Science.gov (United States)

Villeneuve, Daniel L; Angrish, Michelle M; Fortin, Marie C; Katsiadaki, Ioanna; Leonard, Marc; Margiotta-Casaluci, Luigi; Munn, Sharon; O'Brien, Jason M; Pollesch, Nathan L; Smith, L Cody; Zhang, Xiaowei; Knapen, Dries

2018-02-28

Toxicological responses to stressors are more complex than the simple one biological perturbation to one adverse outcome model portrayed by individual adverse outcome pathways (AOPs). Consequently, the AOP framework was designed to facilitate de facto development of AOP networks that can aid understanding and prediction of pleiotropic and interactive effects more common to environmentally realistic, complex exposure scenarios. The present paper introduces nascent concepts related to the qualitative analysis of AOP networks. First, graph theory-based approaches for identifying important topological features are illustrated using two example AOP networks derived from existing AOP descriptions. Second, considerations for identifying the most significant path(s) through an AOP network from either a biological or risk assessment perspective are described. Finally, approaches for identifying interactions among AOPs that may result in additive, synergistic, or antagonistic responses, or previously undefined emergent patterns of response, are introduced. Along with a companion article (Knapen et al. part I), these concepts set the stage for development of tools and case studies that will facilitate more rigorous analysis of AOP networks, and the utility of AOP network-based predictions, for use in research and regulatory decision-making. Collectively, this work addresses one of the major themes identified through a SETAC Horizon Scanning effort focused on advancing the AOP framework. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Finding quasi-optimal network topologies for information transmission in active networks.

Science.gov (United States)

Baptista, Murilo S; de Carvalho, Josué X; Hussein, Mahir S

2008-01-01

This work clarifies the relation between network circuit (topology) and behaviour (information transmission and synchronization) in active networks, e.g. neural networks. As an application, we show how one can find network topologies that are able to transmit a large amount of information, possess a large number of communication channels, and are robust under large variations of the network coupling configuration. This theoretical approach is general and does not depend on the particular dynamic of the elements forming the network, since the network topology can be determined by finding a Laplacian matrix (the matrix that describes the connections and the coupling strengths among the elements) whose eigenvalues satisfy some special conditions. To illustrate our ideas and theoretical approaches, we use neural networks of electrically connected chaotic Hindmarsh-Rose neurons.

Finding quasi-optimal network topologies for information transmission in active networks.

Directory of Open Access Journals (Sweden)

Murilo S Baptista

Full Text Available This work clarifies the relation between network circuit (topology and behaviour (information transmission and synchronization in active networks, e.g. neural networks. As an application, we show how one can find network topologies that are able to transmit a large amount of information, possess a large number of communication channels, and are robust under large variations of the network coupling configuration. This theoretical approach is general and does not depend on the particular dynamic of the elements forming the network, since the network topology can be determined by finding a Laplacian matrix (the matrix that describes the connections and the coupling strengths among the elements whose eigenvalues satisfy some special conditions. To illustrate our ideas and theoretical approaches, we use neural networks of electrically connected chaotic Hindmarsh-Rose neurons.

Research on Evolutionary Mechanism of Agile Supply Chain Network via Complex Network Theory

Directory of Open Access Journals (Sweden)

Nai-Ru Xu

2016-01-01

Full Text Available The paper establishes the evolutionary mechanism model of agile supply chain network by means of complex network theory which can be used to describe the growth process of the agile supply chain network and analyze the complexity of the agile supply chain network. After introducing the process and the suitability of taking complex network theory into supply chain network research, the paper applies complex network theory into the agile supply chain network research, analyzes the complexity of agile supply chain network, presents the evolutionary mechanism of agile supply chain network based on complex network theory, and uses Matlab to simulate degree distribution, average path length, clustering coefficient, and node betweenness. Simulation results show that the evolution result displays the scale-free property. It lays the foundations of further research on agile supply chain network based on complex network theory.

Seeded Bayesian Networks: Constructing genetic networks from microarray data

Directory of Open Access Journals (Sweden)

Quackenbush John

2008-07-01

Full Text Available Abstract Background DNA microarrays and other genomics-inspired technologies provide large datasets that often include hidden patterns of correlation between genes reflecting the complex processes that underlie cellular metabolism and physiology. The challenge in analyzing large-scale expression data has been to extract biologically meaningful inferences regarding these processes – often represented as networks – in an environment where the datasets are often imperfect and biological noise can obscure the actual signal. Although many techniques have been developed in an attempt to address these issues, to date their ability to extract meaningful and predictive network relationships has been limited. Here we describe a method that draws on prior information about gene-gene interactions to infer biologically relevant pathways from microarray data. Our approach consists of using preliminary networks derived from the literature and/or protein-protein interaction data as seeds for a Bayesian network analysis of microarray results. Results Through a bootstrap analysis of gene expression data derived from a number of leukemia studies, we demonstrate that seeded Bayesian Networks have the ability to identify high-confidence gene-gene interactions which can then be validated by comparison to other sources of pathway data. Conclusion The use of network seeds greatly improves the ability of Bayesian Network analysis to learn gene interaction networks from gene expression data. We demonstrate that the use of seeds derived from the biomedical literature or high-throughput protein-protein interaction data, or the combination, provides improvement over a standard Bayesian Network analysis, allowing networks involving dynamic processes to be deduced from the static snapshots of biological systems that represent the most common source of microarray data. Software implementing these methods has been included in the widely used TM4 microarray analysis package.

Hierarchical thinking in network biology: the unbiased modularization of biochemical networks.

Science.gov (United States)

Papin, Jason A; Reed, Jennifer L; Palsson, Bernhard O

2004-12-01

As reconstructed biochemical reaction networks continue to grow in size and scope, there is a growing need to describe the functional modules within them. Such modules facilitate the study of biological processes by deconstructing complex biological networks into conceptually simple entities. The definition of network modules is often based on intuitive reasoning. As an alternative, methods are being developed for defining biochemical network modules in an unbiased fashion. These unbiased network modules are mathematically derived from the structure of the whole network under consideration.

Introduction to computer networking

CERN Document Server

Robertazzi, Thomas G

2017-01-01

This book gives a broad look at both fundamental networking technology and new areas that support it and use it. It is a concise introduction to the most prominent, recent technological topics in computer networking. Topics include network technology such as wired and wireless networks, enabling technologies such as data centers, software defined networking, cloud and grid computing and applications such as networks on chips, space networking and network security. The accessible writing style and non-mathematical treatment makes this a useful book for the student, network and communications engineer, computer scientist and IT professional. • Features a concise, accessible treatment of computer networking, focusing on new technological topics; • Provides non-mathematical introduction to networks in their most common forms today;< • Includes new developments in switching, optical networks, WiFi, Bluetooth, LTE, 5G, and quantum cryptography.

Understanding resilience in industrial symbiosis networks: insights from network analysis.

Science.gov (United States)

Chopra, Shauhrat S; Khanna, Vikas

2014-08-01

Industrial symbiotic networks are based on the principles of ecological systems where waste equals food, to develop synergistic networks. For example, industrial symbiosis (IS) at Kalundborg, Denmark, creates an exchange network of waste, water, and energy among companies based on contractual dependency. Since most of the industrial symbiotic networks are based on ad-hoc opportunities rather than strategic planning, gaining insight into disruptive scenarios is pivotal for understanding the balance of resilience and sustainability and developing heuristics for designing resilient IS networks. The present work focuses on understanding resilience as an emergent property of an IS network via a network-based approach with application to the Kalundborg Industrial Symbiosis (KIS). Results from network metrics and simulated disruptive scenarios reveal Asnaes power plant as the most critical node in the system. We also observe a decrease in the vulnerability of nodes and reduction in single points of failure in the system, suggesting an increase in the overall resilience of the KIS system from 1960 to 2010. Based on our findings, we recommend design strategies, such as increasing diversity, redundancy, and multi-functionality to ensure flexibility and plasticity, to develop resilient and sustainable industrial symbiotic networks. Copyright © 2014 Elsevier Ltd. All rights reserved.

Network Experiences Lead to the Adaption of a Firm’s Network Competence

Directory of Open Access Journals (Sweden)

Bianka Kühne

2011-12-01

Full Text Available Networks become increasingly important as external sources of innovation for firms. Through networks firms get incontact with different actors with whom they can exchange information and collaborate. A firm’s ability to be asuccessful network actor depends on its network competence. This term can be defined as having the necessaryknowledge, skills and qualifications for networking as well as using them effectively. In this paper we investigate thelink between a firm’s network competence and the benefits resulting from it in a two‐way direction. First, thenetwork competence of the firm facilitates the adoption of information from other network actors which may leadto innovation success. Second the perceived network benefits shall in their turn influence the network competenceof the firm. Consequently, firms will adapt their network strategy corresponding their experiences. The objective ofthis paper is to investigate the dynamics of networking and its influence on the firm’s network competence. For thisexploratory research 3 Belgian networks are examined. In‐depth interviews are used in combination with semistructuredinterview guides to conduct the research. Our results indicate that some firms perceive benefits fromtheir network efforts, for others it is more a burden. Furthermore, in some of our cases we found that positiveexperiences with clear benefits motivate the firm to enhance its network competence. This is illustrated by the factthat collaborations are more frequently initiated, trust is more easily build, firms are more open to communicateinformation and the confidentiality threshold is overcome.

Network cohesion

OpenAIRE

Cavalcanti, Tiago V. V.; Giannitsarou, Chryssi; Johnson, Charles R.

2016-01-01

This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s00199-016-0992-1 We define a measure of network cohesion and show how it arises naturally in a broad class of dynamic models of endogenous perpetual growth with network externalities. Via a standard growth model, we show why network cohesion is crucial for conditional convergence and explain that as cohesion increases, convergence is faster. We prove properties of network cohesion and d...

Ecological network analysis for a virtual water network.

Science.gov (United States)

Fang, Delin; Chen, Bin

2015-06-02

The notions of virtual water flows provide important indicators to manifest the water consumption and allocation between different sectors via product transactions. However, the configuration of virtual water network (VWN) still needs further investigation to identify the water interdependency among different sectors as well as the network efficiency and stability in a socio-economic system. Ecological network analysis is chosen as a useful tool to examine the structure and function of VWN and the interactions among its sectors. A balance analysis of efficiency and redundancy is also conducted to describe the robustness (RVWN) of VWN. Then, network control analysis and network utility analysis are performed to investigate the dominant sectors and pathways for virtual water circulation and the mutual relationships between pairwise sectors. A case study of the Heihe River Basin in China shows that the balance between efficiency and redundancy is situated on the left side of the robustness curve with less efficiency and higher redundancy. The forestation, herding and fishing sectors and industrial sectors are found to be the main controllers. The network tends to be more mutualistic and synergic, though some competitive relationships that weaken the virtual water circulation still exist.

Network motif frequency vectors reveal evolving metabolic network organisation.

Science.gov (United States)

Pearcy, Nicole; Crofts, Jonathan J; Chuzhanova, Nadia

2015-01-01

At the systems level many organisms of interest may be described by their patterns of interaction, and as such, are perhaps best characterised via network or graph models. Metabolic networks, in particular, are fundamental to the proper functioning of many important biological processes, and thus, have been widely studied over the past decade or so. Such investigations have revealed a number of shared topological features, such as a short characteristic path-length, large clustering coefficient and hierarchical modular structure. However, the extent to which evolutionary and functional properties of metabolism manifest via this underlying network architecture remains unclear. In this paper, we employ a novel graph embedding technique, based upon low-order network motifs, to compare metabolic network structure for 383 bacterial species categorised according to a number of biological features. In particular, we introduce a new global significance score which enables us to quantify important evolutionary relationships that exist between organisms and their physical environments. Using this new approach, we demonstrate a number of significant correlations between environmental factors, such as growth conditions and habitat variability, and network motif structure, providing evidence that organism adaptability leads to increased complexities in the resultant metabolic networks.

Logistical networking: a global storage network

International Nuclear Information System (INIS)

Beck, Micah; Moore, Terry

2005-01-01

The absence of an adequate distributed storage infrastructure for data buffering has become a significant impediment to the flow of work in the wide area, data intensive collaborations that are increasingly characteristic of leading edge research in several fields. One solution to this problem, pioneered under DOE's SciDAC program, is Logistical Networking, which provides a framework for a globally scalable, maximally interoperable storage network based on the Internet Backplane Protocol (IBP). This paper provides a brief overview of the Logistical Networking (LN) architecture, the middleware developed to exploit its value, and a few of the applications that some of research communities have made of it

Evaluating the Limits of Network Topology Inference Via Virtualized Network Emulation

Science.gov (United States)

2015-06-01

virtualized environment. First, we automatically build topological ground truth according to various network generation models and create emulated Cisco ...to various network generation models and create emulated Cisco router networks by leveraging and modifying existing emulation software. We then au... markets , to verifying compliance with policy, as in recent “network neutrality” rules established in the United States. The Internet is a network of

Modelling computer networks

International Nuclear Information System (INIS)

Max, G

2011-01-01

Traffic models in computer networks can be described as a complicated system. These systems show non-linear features and to simulate behaviours of these systems are also difficult. Before implementing network equipments users wants to know capability of their computer network. They do not want the servers to be overloaded during temporary traffic peaks when more requests arrive than the server is designed for. As a starting point for our study a non-linear system model of network traffic is established to exam behaviour of the network planned. The paper presents setting up a non-linear simulation model that helps us to observe dataflow problems of the networks. This simple model captures the relationship between the competing traffic and the input and output dataflow. In this paper, we also focus on measuring the bottleneck of the network, which was defined as the difference between the link capacity and the competing traffic volume on the link that limits end-to-end throughput. We validate the model using measurements on a working network. The results show that the initial model estimates well main behaviours and critical parameters of the network. Based on this study, we propose to develop a new algorithm, which experimentally determines and predict the available parameters of the network modelled.

Optical Access Networks

Science.gov (United States)

Zheng, Jun; Ansari, Nirwan

2005-06-01

Call for Papers: Optical Access Networks With the wide deployment of fiber-optic technology over the past two decades, we have witnessed a tremendous growth of bandwidth capacity in the backbone networks of today's telecommunications infrastructure. However, access networks, which cover the "last-mile" areas and serve numerous residential and small business users, have not been scaled up commensurately. The local subscriber lines for telephone and cable television are still using twisted pairs and coaxial cables. Most residential connections to the Internet are still through dial-up modems operating at a low speed on twisted pairs. As the demand for access bandwidth increases with emerging high-bandwidth applications, such as distance learning, high-definition television (HDTV), and video on demand (VoD), the last-mile access networks have become a bandwidth bottleneck in today's telecommunications infrastructure. To ease this bottleneck, it is imperative to provide sufficient bandwidth capacity in the access networks to open the bottleneck and thus present more opportunities for the provisioning of multiservices. Optical access solutions promise huge bandwidth to service providers and low-cost high-bandwidth services to end users and are therefore widely considered the technology of choice for next-generation access networks. To realize the vision of optical access networks, however, many key issues still need to be addressed, such as network architectures, signaling protocols, and implementation standards. The major challenges lie in the fact that an optical solution must be not only robust, scalable, and flexible, but also implemented at a low cost comparable to that of existing access solutions in order to increase the economic viability of many potential high-bandwidth applications. In recent years, optical access networks have been receiving tremendous attention from both academia and industry. A large number of research activities have been carried out or

Security-Enhanced Autonomous Network Management for Space Networking, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — NASA's Space Communications and Navigation (SCaN) program is integrating its three current agency networks: Space Network (SN), Deep Space Network (DSN), and Near...

WDM Core Networks : regenerator placement and green networking

OpenAIRE

Youssef , Mayssa

2011-01-01

As Operators strive today to optimize their networks, considerations of cost, availability, eco-sustainability, and quality of service are beginning to converge. Solutions that reduce capital and operational expenditures not only save money, but also tend to reduce the environmental impact. In "opaque" networks, optical signals undergo expensive electrical regeneration systematically at each node. In "transparent" networks, signal quality deteriorates due to the accumulation of physical impai...

Technical Network

CERN Multimedia

2007-01-01

In order to optimize the management of the Technical Network (TN), to ease the understanding and purpose of devices connected to the TN, and to improve security incident handling, the Technical Network Administrators and the CNIC WG have asked IT/CS to verify the "description" and "tag" fields of devices connected to the TN. Therefore, persons responsible for systems connected to the TN will receive email notifications from IT/CS asking them to add the corresponding information in the network database. Thank you very much for your cooperation. The Technical Network Administrators & the CNIC WG

Enhancing Sensor Network Data Quality via Collaborated Circuit and Network Operations

Directory of Open Access Journals (Sweden)

Lucas Vespa

2013-04-01

Full Text Available In many applications, the quality of data gathered by sensor networks is directly related to the signal-to-noise ratio (SNR of the sensor data being transmitted in the networks. Different from the SNR that is often used in measuring the quality of communication links, the SNR used in this work measures how accurately the data in the network packets represent the physical parameters being sensed. Hence, the signal here refers to the physical parameters that are being monitored by sensor networks; the noise is due to environmental interference and circuit noises at sensor nodes, and packet loss during network transmission. While issues affecting SNR at sensor nodes have been intensively investigated, the impact of network packet loss on data SNR has not attracted significant attention in sensor network design. This paper investigates the impact of packet loss on sensor network data SNR and shows that data SNR is dramatically affected by network packet loss. A data quality metric, based on data SNR, is developed and a cross-layer adaptive scheme is presented to minimize data quality degradation in congested sensor networks. The proposed scheme consists of adaptive downsampling and bit truncation at sensor nodes and intelligent traffic management techniques at the network level. Simulation results are presented to demonstrate the validity and effectiveness of the proposed techniques.

Class network routing

Science.gov (United States)

Bhanot, Gyan [Princeton, NJ; Blumrich, Matthias A [Ridgefield, CT; Chen, Dong [Croton On Hudson, NY; Coteus, Paul W [Yorktown Heights, NY; Gara, Alan G [Mount Kisco, NY; Giampapa, Mark E [Irvington, NY; Heidelberger, Philip [Cortlandt Manor, NY; Steinmacher-Burow, Burkhard D [Mount Kisco, NY; Takken, Todd E [Mount Kisco, NY; Vranas, Pavlos M [Bedford Hills, NY

2009-09-08

Class network routing is implemented in a network such as a computer network comprising a plurality of parallel compute processors at nodes thereof. Class network routing allows a compute processor to broadcast a message to a range (one or more) of other compute processors in the computer network, such as processors in a column or a row. Normally this type of operation requires a separate message to be sent to each processor. With class network routing pursuant to the invention, a single message is sufficient, which generally reduces the total number of messages in the network as well as the latency to do a broadcast. Class network routing is also applied to dense matrix inversion algorithms on distributed memory parallel supercomputers with hardware class function (multicast) capability. This is achieved by exploiting the fact that the communication patterns of dense matrix inversion can be served by hardware class functions, which results in faster execution times.

Properties of healthcare teaming networks as a function of network construction algorithms.

Directory of Open Access Journals (Sweden)

Martin S Zand

Full Text Available Network models of healthcare systems can be used to examine how providers collaborate, communicate, refer patients to each other, and to map how patients traverse the network of providers. Most healthcare service network models have been constructed from patient claims data, using billing claims to link a patient with a specific provider in time. The data sets can be quite large (106-108 individual claims per year, making standard methods for network construction computationally challenging and thus requiring the use of alternate construction algorithms. While these alternate methods have seen increasing use in generating healthcare networks, there is little to no literature comparing the differences in the structural properties of the generated networks, which as we demonstrate, can be dramatically different. To address this issue, we compared the properties of healthcare networks constructed using different algorithms from 2013 Medicare Part B outpatient claims data. Three different algorithms were compared: binning, sliding frame, and trace-route. Unipartite networks linking either providers or healthcare organizations by shared patients were built using each method. We find that each algorithm produced networks with substantially different topological properties, as reflected by numbers of edges, network density, assortativity, clustering coefficients and other structural measures. Provider networks adhered to a power law, while organization networks were best fit by a power law with exponential cutoff. Censoring networks to exclude edges with less than 11 shared patients, a common de-identification practice for healthcare network data, markedly reduced edge numbers and network density, and greatly altered measures of vertex prominence such as the betweenness centrality. Data analysis identified patterns in the distance patients travel between network providers, and a striking set of teaming relationships between providers in the Northeast

An examination of a reciprocal relationship between network governance and network structure

DEFF Research Database (Denmark)

Bergenholtz, Carsten; Goduscheit, René Chester

2011-01-01

In the present article, we examine the network structure and governance of inter-organisational innovation networks over time. Network governance refers to the issue of how to manage and coordinate the relational activities and processes in the network while research on network structure deals...

Correlations in star networks: from Bell inequalities to network inequalities

International Nuclear Information System (INIS)

Tavakoli, Armin; Renou, Marc Olivier; Gisin, Nicolas; Brunner, Nicolas

2017-01-01

The problem of characterizing classical and quantum correlations in networks is considered. Contrary to the usual Bell scenario, where distant observers share a physical system emitted by one common source, a network features several independent sources, each distributing a physical system to a subset of observers. In the quantum setting, the observers can perform joint measurements on initially independent systems, which may lead to strong correlations across the whole network. In this work, we introduce a technique to systematically map a Bell inequality to a family of Bell-type inequalities bounding classical correlations on networks in a star-configuration. Also, we show that whenever a given Bell inequality can be violated by some entangled state ρ , then all the corresponding network inequalities can be violated by considering many copies of ρ distributed in the star network. The relevance of these ideas is illustrated by applying our method to a specific multi-setting Bell inequality. We derive the corresponding network inequalities, and study their quantum violations. (paper)

Robust Learning of High-dimensional Biological Networks with Bayesian Networks

Science.gov (United States)

Nägele, Andreas; Dejori, Mathäus; Stetter, Martin

Structure learning of Bayesian networks applied to gene expression data has become a potentially useful method to estimate interactions between genes. However, the NP-hardness of Bayesian network structure learning renders the reconstruction of the full genetic network with thousands of genes unfeasible. Consequently, the maximal network size is usually restricted dramatically to a small set of genes (corresponding with variables in the Bayesian network). Although this feature reduction step makes structure learning computationally tractable, on the downside, the learned structure might be adversely affected due to the introduction of missing genes. Additionally, gene expression data are usually very sparse with respect to the number of samples, i.e., the number of genes is much greater than the number of different observations. Given these problems, learning robust network features from microarray data is a challenging task. This chapter presents several approaches tackling the robustness issue in order to obtain a more reliable estimation of learned network features.

Structural Behavioral Study on the General Aviation Network Based on Complex Network

Science.gov (United States)

Zhang, Liang; Lu, Na

2017-12-01

The general aviation system is an open and dissipative system with complex structures and behavioral features. This paper has established the system model and network model for general aviation. We have analyzed integral attributes and individual attributes by applying the complex network theory and concluded that the general aviation network has influential enterprise factors and node relations. We have checked whether the network has small world effect, scale-free property and network centrality property which a complex network should have by applying degree distribution of functions and proved that the general aviation network system is a complex network. Therefore, we propose to achieve the evolution process of the general aviation industrial chain to collaborative innovation cluster of advanced-form industries by strengthening network multiplication effect, stimulating innovation performance and spanning the structural hole path.

Shared protection based virtual network mapping in space division multiplexing optical networks

Science.gov (United States)

Zhang, Huibin; Wang, Wei; Zhao, Yongli; Zhang, Jie

2018-05-01

Space Division Multiplexing (SDM) has been introduced to improve the capacity of optical networks. In SDM optical networks, there are multiple cores/modes in each fiber link, and spectrum resources are multiplexed in both frequency and core/modes dimensions. Enabled by network virtualization technology, one SDM optical network substrate can be shared by several virtual networks operators. Similar with point-to-point connection services, virtual networks (VN) also need certain survivability to guard against network failures. Based on customers' heterogeneous requirements on the survivability of their virtual networks, this paper studies the shared protection based VN mapping problem and proposes a Minimum Free Frequency Slots (MFFS) mapping algorithm to improve spectrum efficiency. Simulation results show that the proposed algorithm can optimize SDM optical networks significantly in terms of blocking probability and spectrum utilization.

Fulcrum Network Codes

DEFF Research Database (Denmark)

2015-01-01

Fulcrum network codes, which are a network coding framework, achieve three objectives: (i) to reduce the overhead per coded packet to almost 1 bit per source packet; (ii) to operate the network using only low field size operations at intermediate nodes, dramatically reducing complexity...... in the network; and (iii) to deliver an end-to-end performance that is close to that of a high field size network coding system for high-end receivers while simultaneously catering to low-end ones that can only decode in a lower field size. Sources may encode using a high field size expansion to increase...... the number of dimensions seen by the network using a linear mapping. Receivers can tradeoff computational effort with network delay, decoding in the high field size, the low field size, or a combination thereof....

Network Affordances

DEFF Research Database (Denmark)

Samson, Audrey; Soon, Winnie

2015-01-01

This paper examines the notion of network affordance within the context of network art. Building on Gibson's theory (Gibson, 1979) we understand affordance as the perceived and actual parameters of a thing. We expand on Gaver's affordance of predictability (Gaver, 1996) to include ecological...... and computational parameters of unpredictability. We illustrate the notion of unpredictability by considering four specific works that were included in a network art exhibiton, SPEED SHOW [2.0] Hong Kong. The paper discusses how the artworks are contingent upon the parameteric relations (Parisi, 2013......), of the network. We introduce network affordance as a dynamic framework that could articulate the experienced tension arising from the (visible) symbolic representation of computational processes and its hidden occurrences. We base our proposal on the experience of both organising the SPEED SHOW and participating...

A Quantum Cryptography Communication Network Based on Software Defined Network

Directory of Open Access Journals (Sweden)

Zhang Hongliang

2018-01-01

Full Text Available With the development of the Internet, information security has attracted great attention in today’s society, and quantum cryptography communication network based on quantum key distribution (QKD is a very important part of this field, since the quantum key distribution combined with one-time-pad encryption scheme can guarantee the unconditional security of the information. The secret key generated by quantum key distribution protocols is a very valuable resource, so making full use of key resources is particularly important. Software definition network (SDN is a new type of network architecture, and it separates the control plane and the data plane of network devices through OpenFlow technology, thus it realizes the flexible control of the network resources. In this paper, a quantum cryptography communication network model based on SDN is proposed to realize the flexible control of quantum key resources in the whole cryptography communication network. Moreover, we propose a routing algorithm which takes into account both the hops and the end-to-end availible keys, so that the secret key generated by QKD can be used effectively. We also simulate this quantum cryptography communication network, and the result shows that based on SDN and the proposed routing algorithm the performance of this network is improved since the effective use of the quantum key resources.

Analyzing the factors affecting network lifetime cluster-based wireless sensor network

International Nuclear Information System (INIS)

Malik, A.S.; Qureshi, A.

2010-01-01

Cluster-based wireless sensor networks enable the efficient utilization of the limited energy resources of the deployed sensor nodes and hence prolong the node as well as network lifetime. Low Energy Adaptive Clustering Hierarchy (Leach) is one of the most promising clustering protocol proposed for wireless sensor networks. This paper provides the energy utilization and lifetime analysis for cluster-based wireless sensor networks based upon LEACH protocol. Simulation results identify some important factors that induce unbalanced energy utilization between the sensor nodes and hence affect the network lifetime in these types of networks. These results highlight the need for a standardized, adaptive and distributed clustering technique that can increase the network lifetime by further balancing the energy utilization among sensor nodes. (author)

A Network Primer: Full-Fledged Educational Networks.

Science.gov (United States)

Lehrer, Ariella

1988-01-01

Discusses some of the factors included in choosing appropriate computer networks for the classroom. Describes such networks as those produced by Apple Computer, Corvus Systems, Velan, Berkeley Softworks, Tandy, LAN-TECH, Unisys, and International Business Machines (IBM). (TW)

Network on Target: Remotely Configured Adaptive Tactical Networks

National Research Council Canada - National Science Library

Bordetsky, Alex; Bourakov, Eugene

2006-01-01

The emerging tactical networks represent complex network-centric systems, in which multiple sensors, unmanned vehicles, and geographically distributed units of highly mobile decision makers, transfer...

Network planning study of the metro-optical-network-oriented 3G application

Science.gov (United States)

Gong, Qian; Xu, Rong; Lin, Jin Tong

2005-02-01

To compare with the 2G mobile communication, 3G technologies can supply the perfect service scope and performance. 3G is the trend of the mobile communication. So now to build the transmission network, it is needed to consider how the transmission network to support the 3G applications. For the 3G network architecture, it include the 2 part: Utran access network and core network. So the metro optical network should consider how to build the network to adapt the 3G applications. Include the metro core and access layer. In the metro core, we should consider the network should evolved towards the Mesh architecture with ASON function to realize the fast protection and restoration, quick end-to-end service provision, and high capacity cross-connect matrix etc. In the access layer, the network should have the ability to access the 3G services such as ATM interface with IMA function. In addition, the traffic grooming should be provided to improve the bandwidth utility. In this paper, first we present the MCC network situation, the network planning model will be introduced. Then we present the topology architecture, node capacity and traffic forecast. At last, based on our analysis, we will give a total solution to MCC to build their metro optical network toward to the mesh network with the consideration of 3G services.

Optical network democratization.

Science.gov (United States)

Nejabati, Reza; Peng, Shuping; Simeonidou, Dimitra

2016-03-06

The current Internet infrastructure is not able to support independent evolution and innovation at physical and network layer functionalities, protocols and services, while at same time supporting the increasing bandwidth demands of evolving and heterogeneous applications. This paper addresses this problem by proposing a completely democratized optical network infrastructure. It introduces the novel concepts of the optical white box and bare metal optical switch as key technology enablers for democratizing optical networks. These are programmable optical switches whose hardware is loosely connected internally and is completely separated from their control software. To alleviate their complexity, a multi-dimensional abstraction mechanism using software-defined network technology is proposed. It creates a universal model of the proposed switches without exposing their technological details. It also enables a conventional network programmer to develop network applications for control of the optical network without specific technical knowledge of the physical layer. Furthermore, a novel optical network virtualization mechanism is proposed, enabling the composition and operation of multiple coexisting and application-specific virtual optical networks sharing the same physical infrastructure. Finally, the optical white box and the abstraction mechanism are experimentally evaluated, while the virtualization mechanism is evaluated with simulation. © 2016 The Author(s).

Community Detection for Multiplex Social Networks Based on Relational Bayesian Networks

DEFF Research Database (Denmark)

Jiang, Jiuchuan; Jaeger, Manfred

2014-01-01

Many techniques have been proposed for community detection in social networks. Most of these techniques are only designed for networks defined by a single relation. However, many real networks are multiplex networks that contain multiple types of relations and different attributes on the nodes...

Networks of networks the last frontier of complexity

CERN Document Server

Scala, Antonio

2014-01-01

The present work is meant as a reference to provide an organic and comprehensive view of the most relevant results in the exciting new field of Networks of Networks (NetoNets). Seminal papers have recently been published posing the basis to study what happens when different networks interact, thus providing evidence for the emergence of new, unexpected behaviors and vulnerabilities. From those seminal works, the awareness on the importance understanding Networks of Networks (NetoNets) has spread to the entire community of Complexity Science. The reader will benefit from the experience of some of the most well-recognized leaders in this field. The contents have been aggregated under four headings; General Theory, Phenomenology, Applications and Risk Assessment. The reader will be impressed by the different applications of the general paradigm that span from physiology, to financial risk, to transports. We are currently making the first steps to reduce the distance between the language and the way of thinking o...

Complex Networks

CERN Document Server

Evsukoff, Alexandre; González, Marta

2013-01-01

In the last decade we have seen the emergence of a new inter-disciplinary field focusing on the understanding of networks which are dynamic, large, open, and have a structure sometimes called random-biased. The field of Complex Networks is helping us better understand many complex phenomena such as the spread of  deseases, protein interactions, social relationships, to name but a few. Studies in Complex Networks are gaining attention due to some major scientific breakthroughs proposed by network scientists helping us understand and model interactions contained in large datasets. In fact, if we could point to one event leading to the widespread use of complex network analysis is the availability of online databases. Theories of Random Graphs from Erdös and Rényi from the late 1950s led us to believe that most networks had random characteristics. The work on large online datasets told us otherwise. Starting with the work of Barabási and Albert as well as Watts and Strogatz in the late 1990s, we now know th...

Networking Ethics: A Survey of Bioethics Networks Across the U.S.

Science.gov (United States)

Fausett, Jennifer Kleiner; Gilmore-Szott, Eleanor; Hester, D Micah

2016-06-01

Ethics networks have emerged over the last few decades as a mechanism for individuals and institutions over various regions, cities and states to converge on healthcare-related ethical issues. However, little is known about the development and nature of such networks. In an effort to fill the gap in the knowledge about such networks, a survey was conducted that evaluated the organizational structure, missions and functions, as well as the outcomes/products of ethics networks across the country. Eighteen established bioethics networks were identified via consensus of three search processes and were approached for participation. The participants completed a survey developed for the purposes of this study and distributed via SurveyMonkey. Responses were obtained from 10 of the 18 identified and approached networks regarding topic areas of: Network Composition and Catchment Areas; Network Funding and Expenses; Personnel; Services; and Missions and Accomplishments. Bioethics networks are designed primarily to bring ethics education and support to professionals and hospitals. They do so over specifically defined areas-states, regions, or communities-and each is concerned about how to stay financially healthy. At the same time, the networks work off different organizational models, either as stand-alone organizations or as entities within existing organizational structures.

In-network adaptation of SHVC video in software-defined networks

Science.gov (United States)

Awobuluyi, Olatunde; Nightingale, James; Wang, Qi; Alcaraz Calero, Jose Maria; Grecos, Christos

2016-04-01

Software Defined Networks (SDN), when combined with Network Function Virtualization (NFV) represents a paradigm shift in how future networks will behave and be managed. SDN's are expected to provide the underpinning technologies for future innovations such as 5G mobile networks and the Internet of Everything. The SDN architecture offers features that facilitate an abstracted and centralized global network view in which packet forwarding or dropping decisions are based on application flows. Software Defined Networks facilitate a wide range of network management tasks, including the adaptation of real-time video streams as they traverse the network. SHVC, the scalable extension to the recent H.265 standard is a new video encoding standard that supports ultra-high definition video streams with spatial resolutions of up to 7680×4320 and frame rates of 60fps or more. The massive increase in bandwidth required to deliver these U-HD video streams dwarfs the bandwidth requirements of current high definition (HD) video. Such large bandwidth increases pose very significant challenges for network operators. In this paper we go substantially beyond the limited number of existing implementations and proposals for video streaming in SDN's all of which have primarily focused on traffic engineering solutions such as load balancing. By implementing and empirically evaluating an SDN enabled Media Adaptation Network Entity (MANE) we provide a valuable empirical insight into the benefits and limitations of SDN enabled video adaptation for real time video applications. The SDN-MANE is the video adaptation component of our Video Quality Assurance Manager (VQAM) SDN control plane application, which also includes an SDN monitoring component to acquire network metrics and a decision making engine using algorithms to determine the optimum adaptation strategy for any real time video application flow given the current network conditions. Our proposed VQAM application has been implemented and

ATM Tactical Network - a challenge for the military networks

NARCIS (Netherlands)

Waveren, C.J. van; Luiijf, H.A.M.; Burakowski, W.; Kopertowski, Z.

1997-01-01

The next generation of tactical networks will be based on the ATM technology. The POST-2000 tactical network is just in the designing phase. The objective of this paper is to point out the main problems which should be solved to adopt ATM technology into the tactical network environment. The

Spectral Analysis of Rich Network Topology in Social Networks

Science.gov (United States)

Wu, Leting

2013-01-01

Social networks have received much attention these days. Researchers have developed different methods to study the structure and characteristics of the network topology. Our focus is on spectral analysis of the adjacency matrix of the underlying network. Recent work showed good properties in the adjacency spectral space but there are few…

Promoting Social Network Awareness: A Social Network Monitoring System

Science.gov (United States)

Cadima, Rita; Ferreira, Carlos; Monguet, Josep; Ojeda, Jordi; Fernandez, Joaquin

2010-01-01

To increase communication and collaboration opportunities, members of a community must be aware of the social networks that exist within that community. This paper describes a social network monitoring system--the KIWI system--that enables users to register their interactions and visualize their social networks. The system was implemented in a…

Optimal Network-Topology Design

Science.gov (United States)

Li, Victor O. K.; Yuen, Joseph H.; Hou, Ting-Chao; Lam, Yuen Fung

1987-01-01

Candidate network designs tested for acceptability and cost. Optimal Network Topology Design computer program developed as part of study on topology design and analysis of performance of Space Station Information System (SSIS) network. Uses efficient algorithm to generate candidate network designs consisting of subsets of set of all network components, in increasing order of total costs and checks each design to see whether it forms acceptable network. Technique gives true cost-optimal network and particularly useful when network has many constraints and not too many components. Program written in PASCAL.

Integrating Networking into ATLAS

CERN Document Server

Mc Kee, Shawn Patrick; The ATLAS collaboration

2018-01-01

Networking is foundational to the ATLAS distributed infrastructure and there are many ongoing activities related to networking both within and outside of ATLAS. We will report on the progress in a number of areas exploring ATLAS's use of networking and our ability to monitor the network, analyze metrics from the network, and tune and optimize application and end-host parameters to make the most effective use of the network. Specific topics will include work on Open vSwitch for production systems, network analytics, FTS testing and tuning, and network problem alerting and alarming.

Autonomous vision networking: miniature wireless sensor networks with imaging technology

Science.gov (United States)

Messinger, Gioia; Goldberg, Giora

2006-09-01

The recent emergence of integrated PicoRadio technology, the rise of low power, low cost, System-On-Chip (SOC) CMOS imagers, coupled with the fast evolution of networking protocols and digital signal processing (DSP), created a unique opportunity to achieve the goal of deploying large-scale, low cost, intelligent, ultra-low power distributed wireless sensor networks for the visualization of the environment. Of all sensors, vision is the most desired, but its applications in distributed sensor networks have been elusive so far. Not any more. The practicality and viability of ultra-low power vision networking has been proven and its applications are countless, from security, and chemical analysis to industrial monitoring, asset tracking and visual recognition, vision networking represents a truly disruptive technology applicable to many industries. The presentation discusses some of the critical components and technologies necessary to make these networks and products affordable and ubiquitous - specifically PicoRadios, CMOS imagers, imaging DSP, networking and overall wireless sensor network (WSN) system concepts. The paradigm shift, from large, centralized and expensive sensor platforms, to small, low cost, distributed, sensor networks, is possible due to the emergence and convergence of a few innovative technologies. Avaak has developed a vision network that is aided by other sensors such as motion, acoustic and magnetic, and plans to deploy it for use in military and commercial applications. In comparison to other sensors, imagers produce large data files that require pre-processing and a certain level of compression before these are transmitted to a network server, in order to minimize the load on the network. Some of the most innovative chemical detectors currently in development are based on sensors that change color or pattern in the presence of the desired analytes. These changes are easily recorded and analyzed by a CMOS imager and an on-board DSP processor

Network Transformations in Economy

Directory of Open Access Journals (Sweden)

Bolychev O.

2014-09-01

Full Text Available In the context of ever-increasing market competition, networked interactions play a special role in the economy. The network form of entrepreneurship is increasingly viewed as an effective organizational structure to create a market value embedded in innovative business solutions. The authors study the characteristics of a network as an economic category and emphasize certain similarities between Rus sian and international approaches to identifying interactions of economic systems based on the network principle. The paper focuses on the types of networks widely used in the economy. The authors analyze the transformation of business networks along two lines: from an intra- to an inter-firm network and from an inter-firm to an inter-organizational network. The possible forms of network formation are described depending on the strength of connections and the type of integration. The drivers and reasons behind process of transition from a hierarchical model of the organizational structure to a network type are identified. The authors analyze the advantages of creating inter-firm networks and discuss the features of inter-organizational networks as compares to inter-firm ones. The article summarizes the reasons for and advantages of participation in inter-rganizational networks and identifies the main barriers to the formation of inter-organizational network.

Reliable Communication in Wireless Meshed Networks using Network Coding

DEFF Research Database (Denmark)

Pahlevani, Peyman; Paramanathan, Achuthan; Hundebøll, Martin

2012-01-01

The advantages of network coding have been extensively studied in the field of wireless networks. Integrating network coding with existing IEEE 802.11 MAC layer is a challenging problem. The IEEE 802.11 MAC does not provide any reliability mechanisms for overheard packets. This paper addresses...... this problem and suggests different mechanisms to support reliability as part of the MAC protocol. Analytical expressions to this problem are given to qualify the performance of the modified network coding. These expressions are confirmed by numerical result. While the suggested reliability mechanisms...

Group Centric Networking: Large Scale Over the Air Testing of Group Centric Networking

Science.gov (United States)

2016-11-01

Large Scale Over-the-Air Testing of Group Centric Networking Logan Mercer, Greg Kuperman, Andrew Hunter, Brian Proulx MIT Lincoln Laboratory...performance of Group Centric Networking (GCN), a networking protocol developed for robust and scalable communications in lossy networks where users are...devices, and the ad-hoc nature of the network . Group Centric Networking (GCN) is a proposed networking protocol that addresses challenges specific to

A Collaborative Learning Network Approach to Improvement: The CUSP Learning Network.

Science.gov (United States)

Weaver, Sallie J; Lofthus, Jennifer; Sawyer, Melinda; Greer, Lee; Opett, Kristin; Reynolds, Catherine; Wyskiel, Rhonda; Peditto, Stephanie; Pronovost, Peter J

2015-04-01

Collaborative improvement networks draw on the science of collaborative organizational learning and communities of practice to facilitate peer-to-peer learning, coaching, and local adaption. Although significant improvements in patient safety and quality have been achieved through collaborative methods, insight regarding how collaborative networks are used by members is needed. Improvement Strategy: The Comprehensive Unit-based Safety Program (CUSP) Learning Network is a multi-institutional collaborative network that is designed to facilitate peer-to-peer learning and coaching specifically related to CUSP. Member organizations implement all or part of the CUSP methodology to improve organizational safety culture, patient safety, and care quality. Qualitative case studies developed by participating members examine the impact of network participation across three levels of analysis (unit, hospital, health system). In addition, results of a satisfaction survey designed to evaluate member experiences were collected to inform network development. Common themes across case studies suggest that members found value in collaborative learning and sharing strategies across organizational boundaries related to a specific improvement strategy. The CUSP Learning Network is an example of network-based collaborative learning in action. Although this learning network focuses on a particular improvement methodology-CUSP-there is clear potential for member-driven learning networks to grow around other methods or topic areas. Such collaborative learning networks may offer a way to develop an infrastructure for longer-term support of improvement efforts and to more quickly diffuse creative sustainment strategies.

Evolutionary features of academic articles co-keyword network and keywords co-occurrence network: Based on two-mode affiliation network

Science.gov (United States)

Li, Huajiao; An, Haizhong; Wang, Yue; Huang, Jiachen; Gao, Xiangyun

2016-05-01

Keeping abreast of trends in the articles and rapidly grasping a body of article's key points and relationship from a holistic perspective is a new challenge in both literature research and text mining. As the important component, keywords can present the core idea of the academic article. Usually, articles on a single theme or area could share one or some same keywords, and we can analyze topological features and evolution of the articles co-keyword networks and keywords co-occurrence networks to realize the in-depth analysis of the articles. This paper seeks to integrate statistics, text mining, complex networks and visualization to analyze all of the academic articles on one given theme, complex network(s). All 5944 ;complex networks; articles that were published between 1990 and 2013 and are available on the Web of Science are extracted. Based on the two-mode affiliation network theory, a new frontier of complex networks, we constructed two different networks, one taking the articles as nodes, the co-keyword relationships as edges and the quantity of co-keywords as the weight to construct articles co-keyword network, and another taking the articles' keywords as nodes, the co-occurrence relationships as edges and the quantity of simultaneous co-occurrences as the weight to construct keyword co-occurrence network. An integrated method for analyzing the topological features and evolution of the articles co-keyword network and keywords co-occurrence networks is proposed, and we also defined a new function to measure the innovation coefficient of the articles in annual level. This paper provides a useful tool and process for successfully achieving in-depth analysis and rapid understanding of the trends and relationships of articles in a holistic perspective.

Network topology analysis.

Energy Technology Data Exchange (ETDEWEB)

Kalb, Jeffrey L.; Lee, David S.

2008-01-01

Emerging high-bandwidth, low-latency network technology has made network-based architectures both feasible and potentially desirable for use in satellite payload architectures. The selection of network topology is a critical component when developing these multi-node or multi-point architectures. This study examines network topologies and their effect on overall network performance. Numerous topologies were reviewed against a number of performance, reliability, and cost metrics. This document identifies a handful of good network topologies for satellite applications and the metrics used to justify them as such. Since often multiple topologies will meet the requirements of the satellite payload architecture under development, the choice of network topology is not easy, and in the end the choice of topology is influenced by both the design characteristics and requirements of the overall system and the experience of the developer.

Dissemination Patterns and Associated Network Effects of Sentiments in Social Networks

DEFF Research Database (Denmark)

Hillmann, Robert; Trier, Matthias

2012-01-01

. The dissemination patterns analyzed in this study consist of network motifs based on triples of actors and the ties among them. These motifs are associated with common social network effects to derive meaningful insights about dissemination activities. The data basis includes several thousand social networks...... with textual messages classified according to embedded positive and negative sentiments. Based on this data, sub-networks are extracted and analyzed with a dynamic network motif analysis to determine dissemination patterns and associated network effects. Results indicate that the emergence of digital social...... networks exhibits a strong tendency towards reciprocity, followed by the dominance of hierarchy as an intermediate step leading to social clustering with hubs and transitivity effects for both positive and negative sentiments to the same extend. Sentiments embedded in exchanged textual messages do only...

Optical Access Networks

Science.gov (United States)

Zheng, Jun; Ansari, Nirwan

2005-01-01

Call for Papers: Optical Access Networks Guest Editors Jun Zheng, University of Ottawa Nirwan Ansari, New Jersey Institute of Technology Submission Deadline: 1 June 2005 Background With the wide deployment of fiber-optic technology over the past two decades, we have witnessed a tremendous growth of bandwidth capacity in the backbone networks of today's telecommunications infrastructure. However, access networks, which cover the "last-mile" areas and serve numerous residential and small business users, have not been scaled up commensurately. The local subscriber lines for telephone and cable television are still using twisted pairs and coaxial cables. Most residential connections to the Internet are still through dial-up modems operating at a low speed on twisted pairs. As the demand for access bandwidth increases with emerging high-bandwidth applications, such as distance learning, high-definition television (HDTV), and video on demand (VoD), the last-mile access networks have become a bandwidth bottleneck in today's telecommunications infrastructure. To ease this bottleneck, it is imperative to provide sufficient bandwidth capacity in the access networks to open the bottleneck and thus present more opportunities for the provisioning of multiservices. Optical access solutions promise huge bandwidth to service providers and low-cost high-bandwidth services to end users and are therefore widely considered the technology of choice for next-generation access networks. To realize the vision of optical access networks, however, many key issues still need to be addressed, such as network architectures, signaling protocols, and implementation standards. The major challenges lie in the fact that an optical solution must be not only robust, scalable, and flexible, but also implemented at a low cost comparable to that of existing access solutions in order to increase the economic viability of many potential high-bandwidth applications. In recent years, optical access networks

Networks in ATLAS

Science.gov (United States)

McKee, Shawn; ATLAS Collaboration

2017-10-01

Networks have played a critical role in high-energy physics (HEP), enabling us to access and effectively utilize globally distributed resources to meet the needs of our physicists. Because of their importance in enabling our grid computing infrastructure many physicists have taken leading roles in research and education (R&E) networking, participating in, and even convening, network related meetings and research programs with the broader networking community worldwide. This has led to HEP benefiting from excellent global networking capabilities for little to no direct cost. However, as other science domains ramp-up their need for similar networking it becomes less clear that this situation will continue unchanged. What this means for ATLAS in particular needs to be understood. ATLAS has evolved its computing model since the LHC started based upon its experience with using globally distributed resources. The most significant theme of those changes has been increased reliance upon, and use of, its networks. We will report on a number of networking initiatives in ATLAS including participation in the global perfSONAR network monitoring and measuring efforts of WLCG and OSG, the collaboration with the LHCOPN/LHCONE effort, the integration of network awareness into PanDA, the use of the evolving ATLAS analytics framework to better understand our networks and the changes in our DDM system to allow remote access to data. We will also discuss new efforts underway that are exploring the inclusion and use of software defined networks (SDN) and how ATLAS might benefit from: • Orchestration and optimization of distributed data access and data movement. • Better control of workflows, end to end. • Enabling prioritization of time-critical vs normal tasks • Improvements in the efficiency of resource usage

Identity and Professional Networking.

Science.gov (United States)

Raj, Medha; Fast, Nathanael J; Fisher, Oliver

2017-06-01

Despite evidence that large professional networks afford a host of financial and professional benefits, people vary in how motivated they are to build such networks. To help explain this variance, the present article moves beyond a rational self-interest account to examine the possibility that identity shapes individuals' intentions to network. Study 1 established a positive association between viewing professional networking as identity-congruent and the tendency to prioritize strengthening and expanding one's professional network. Study 2 revealed that manipulating the salience of the self affects networking intentions, but only among those high in networking identity-congruence. Study 3 further established causality by experimentally manipulating identity-congruence to increase networking intentions. Study 4 examined whether identity or self-interest is a better predictor of networking intentions, providing support for the former. These findings indicate that identity influences the networks people develop. Implications for research on the self, identity-based motivation, and professional networking are discussed.

Northern emporia and maritime networks. Modelling past communication using archaeological network analysis

DEFF Research Database (Denmark)

Sindbæk, Søren Michael

2015-01-01

preserve patterns of thisinteraction. Formal network analysis and modelling holds the potential to identify anddemonstrate such patterns, where traditional methods often prove inadequate. Thearchaeological study of communication networks in the past, however, calls for radically different analytical...... this is not a problem of network analysis, but network synthesis: theclassic problem of cracking codes or reconstructing black-box circuits. It is proposedthat archaeological approaches to network synthesis must involve a contextualreading of network data: observations arising from individual contexts, morphologies...

Social networks in primates: smart and tolerant species have more efficient networks.

Science.gov (United States)

Pasquaretta, Cristian; Levé, Marine; Claidière, Nicolas; van de Waal, Erica; Whiten, Andrew; MacIntosh, Andrew J J; Pelé, Marie; Bergstrom, Mackenzie L; Borgeaud, Christèle; Brosnan, Sarah F; Crofoot, Margaret C; Fedigan, Linda M; Fichtel, Claudia; Hopper, Lydia M; Mareno, Mary Catherine; Petit, Odile; Schnoell, Anna Viktoria; di Sorrentino, Eugenia Polizzi; Thierry, Bernard; Tiddi, Barbara; Sueur, Cédric

2014-12-23

Network optimality has been described in genes, proteins and human communicative networks. In the latter, optimality leads to the efficient transmission of information with a minimum number of connections. Whilst studies show that differences in centrality exist in animal networks with central individuals having higher fitness, network efficiency has never been studied in animal groups. Here we studied 78 groups of primates (24 species). We found that group size and neocortex ratio were correlated with network efficiency. Centralisation (whether several individuals are central in the group) and modularity (how a group is clustered) had opposing effects on network efficiency, showing that tolerant species have more efficient networks. Such network properties affecting individual fitness could be shaped by natural selection. Our results are in accordance with the social brain and cultural intelligence hypotheses, which suggest that the importance of network efficiency and information flow through social learning relates to cognitive abilities.

Epidemic Network Failures in Optical Transport Networks

DEFF Research Database (Denmark)

Ruepp, Sarah Renée; Katsikas, Dimitrios; Fagertun, Anna Manolova

2013-01-01

This paper presents a failure propagation model for transport networks which are affected by epidemic failures. The network is controlled using the GMPLS protocol suite. The Susceptible Infected Disabled (SID) epidemic model is investigated and new signaling functionality of GMPLS to support...

Network on Target: Remotely Configured Adaptive Tactical Networks

National Research Council Canada - National Science Library

Bordetsky, Alex; Bourakov, Eugene

2006-01-01

.... The node mobility as well as ad hoc network topology reconfiguration becomes a powerful control option, which network operators or intelligent management agents could apply to provide for self...

Analysis of Network Parameters Influencing Performance of Hybrid Multimedia Networks

Directory of Open Access Journals (Sweden)

Dominik Kovac

2013-10-01

Full Text Available Multimedia networks is an emerging subject that currently attracts the attention of research and industrial communities. This environment provides new entertainment services and business opportunities merged with all well-known network services like VoIP calls or file transfers. Such a heterogeneous system has to be able satisfy all network and end-user requirements which are increasing constantly. Therefore the simulation tools enabling deep analysis in order to find the key performance indicators and factors which influence the overall quality for specific network service the most are highly needed. This paper provides a study on the network parameters like communication technology, routing protocol, QoS mechanism, etc. and their effect on the performance of hybrid multimedia network. The analysis was performed in OPNET Modeler environment and the most interesting results are discussed at the end of this paper

Software defined wireless sensor networks application opportunities for efficient network management: a survey

CSIR Research Space (South Africa)

Modieginyane, KM

2017-03-01

Full Text Available Wireless Sensor Networks (WSNs) are commonly used information technologies of modern networking and computing platforms. Today's network computing applications are faced with a high demand of powerful network functionalities. Functional network...

Stories in Networks and Networks in Stories: A Tri-Modal Model for Mixed-Methods Social Network Research on Teachers

Science.gov (United States)

Baker-Doyle, Kira J.

2015-01-01

Social network research on teachers and schools has risen exponentially in recent years as an innovative method to reveal the role of social networks in education. However, scholars are still exploring ways to incorporate traditional quantitative methods of Social Network Analysis (SNA) with qualitative approaches to social network research. This…

Developing cyber security architecture for military networks using cognitive networking

OpenAIRE

Kärkkäinen, Anssi

2015-01-01

In recent years, the importance of cyber security has increased. Cyber security has not become a critical issue only for governmental or business actors, but also for armed forces that nowadays rely on national or even global networks in their daily activities. The Network Centric Warfare (NCW) paradigm has increased the significance of networking during last decades as it enables information superiority in which military combat power increased by networking the battlefield actors from perspe...

Game theory in communication networks cooperative resolution of interactive networking scenarios

CERN Document Server

Antoniou, Josephina

2012-01-01

A mathematical tool for scientists and researchers who work with computer and communication networks, Game Theory in Communication Networks: Cooperative Resolution of Interactive Networking Scenarios addresses the question of how to promote cooperative behavior in interactive situations between heterogeneous entities in communication networking scenarios. It explores network design and management from a theoretical perspective, using game theory and graph theory to analyze strategic situations and demonstrate profitable behaviors of the cooperative entities. The book promotes the use of Game T

Advanced network programming principles and techniques : network application programming with Java

CERN Document Server

Ciubotaru, Bogdan

2013-01-01

Answering the need for an accessible overview of the field, this text/reference presents a manageable introduction to both the theoretical and practical aspects of computer networks and network programming. Clearly structured and easy to follow, the book describes cutting-edge developments in network architectures, communication protocols, and programming techniques and models, supported by code examples for hands-on practice with creating network-based applications. Features: presents detailed coverage of network architectures; gently introduces the reader to the basic ideas underpinning comp

An Inter-Networking Mechanism with Stepwise Synchronization for Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Masayuki Murata

2011-08-01

Full Text Available To realize the ambient information society, multiple wireless networks deployed in the region and devices carried by users are required to cooperate with each other. Since duty cycles and operational frequencies are different among networks, we need a mechanism to allow networks to efficiently exchange messages. For this purpose, we propose a novel inter-networking mechanism where two networks are synchronized with each other in a moderate manner, which we call stepwise synchronization. With our proposal, to bridge the gap between intrinsic operational frequencies, nodes near the border of networks adjust their operational frequencies in a stepwise fashion based on the pulse-coupled oscillator model as a fundamental theory of synchronization. Through simulation experiments, we show that the communication delay and the energy consumption of border nodes are reduced, which enables wireless sensor networks to communicate longer with each other.

The Analysis of SARDANA HPON Networks Using the HPON Network Configurator

Directory of Open Access Journals (Sweden)

Rastislav Roka

2013-01-01

Full Text Available NG-PON systems present optical access infrastructures to support various applications of the many service providers. In the near future, we can expect NG-PON technologies with different motivations for developing of HPON networks. The HPON is a hybrid passive optical network in a way that utilizes on a physical layer both TDM and WDM multiplexing principles together. The HPON network utilizes similar or soft revised topologies as TDM-PON architectures. In this second paper, requirements for the SARDANA HPON networks are introduced. A main part of the paper is dedicated to presentation of the HPON network configurator that allows configurating and analyzing the SARDANA HPON characteristics from a viewpoint of various specific network parameters. Finally, a short introduction to the comparison of the SARDANA and SUCCESS HPON networks based on simulation results is presented.

The Analysis of SUCCESS HPON Networks Using the HPON Network Configurator

Directory of Open Access Journals (Sweden)

Rastislav Roka

2013-01-01

Full Text Available NG-PON systems present optical access infrastructures to support various applications of the many service providers. In the near future, we can expect NG-PON technologies with different motivations for developing of HPON networks. The HPON is a hybrid passive optical network in a way that utilizes on a physical layer both TDM and WDM multiplexing principles together. The HPON network utilizes similar or soft revised topologies as TDM-PON architectures. In this first paper, design requirements for SUCCESS HPON networks are introduced. A main part of the paper is dedicated to presentation of the HPON network configurator that allows configurating and analyzing the SUCCESS HPON characteristics from a viewpoint of various specific network parameters. Finally, a short introduction to the comparison of the SUCCESS and SARDANA HPON networks based on simulation results is presented.

Neural Networks

International Nuclear Information System (INIS)

Smith, Patrick I.

2003-01-01

Physicists use large detectors to measure particles created in high-energy collisions at particle accelerators. These detectors typically produce signals indicating either where ionization occurs along the path of the particle, or where energy is deposited by the particle. The data produced by these signals is fed into pattern recognition programs to try to identify what particles were produced, and to measure the energy and direction of these particles. Ideally, there are many techniques used in this pattern recognition software. One technique, neural networks, is particularly suitable for identifying what type of particle caused by a set of energy deposits. Neural networks can derive meaning from complicated or imprecise data, extract patterns, and detect trends that are too complex to be noticed by either humans or other computer related processes. To assist in the advancement of this technology, Physicists use a tool kit to experiment with several neural network techniques. The goal of this research is interface a neural network tool kit into Java Analysis Studio (JAS3), an application that allows data to be analyzed from any experiment. As the final result, a physicist will have the ability to train, test, and implement a neural network with the desired output while using JAS3 to analyze the results or output. Before an implementation of a neural network can take place, a firm understanding of what a neural network is and how it works is beneficial. A neural network is an artificial representation of the human brain that tries to simulate the learning process [5]. It is also important to think of the word artificial in that definition as computer programs that use calculations during the learning process. In short, a neural network learns by representative examples. Perhaps the easiest way to describe the way neural networks learn is to explain how the human brain functions. The human brain contains billions of neural cells that are responsible for processing

Default network modulation and large-scale network interactivity in healthy young and old adults.

Science.gov (United States)

Spreng, R Nathan; Schacter, Daniel L

2012-11-01

We investigated age-related changes in default, attention, and control network activity and their interactions in young and old adults. Brain activity during autobiographical and visuospatial planning was assessed using multivariate analysis and with intrinsic connectivity networks as regions of interest. In both groups, autobiographical planning engaged the default network while visuospatial planning engaged the attention network, consistent with a competition between the domains of internalized and externalized cognition. The control network was engaged for both planning tasks. In young subjects, the control network coupled with the default network during autobiographical planning and with the attention network during visuospatial planning. In old subjects, default-to-control network coupling was observed during both planning tasks, and old adults failed to deactivate the default network during visuospatial planning. This failure is not indicative of default network dysfunction per se, evidenced by default network engagement during autobiographical planning. Rather, a failure to modulate the default network in old adults is indicative of a lower degree of flexible network interactivity and reduced dynamic range of network modulation to changing task demands.

Social networks in primates: smart and tolerant species have more efficient networks

Science.gov (United States)

Pasquaretta, Cristian; Levé, Marine; Claidière, Nicolas; van de Waal, Erica; Whiten, Andrew; MacIntosh, Andrew J. J.; Pelé, Marie; Bergstrom, Mackenzie L.; Borgeaud, Christèle; Brosnan, Sarah F.; Crofoot, Margaret C.; Fedigan, Linda M.; Fichtel, Claudia; Hopper, Lydia M.; Mareno, Mary Catherine; Petit, Odile; Schnoell, Anna Viktoria; di Sorrentino, Eugenia Polizzi; Thierry, Bernard; Tiddi, Barbara; Sueur, Cédric

2014-01-01

Network optimality has been described in genes, proteins and human communicative networks. In the latter, optimality leads to the efficient transmission of information with a minimum number of connections. Whilst studies show that differences in centrality exist in animal networks with central individuals having higher fitness, network efficiency has never been studied in animal groups. Here we studied 78 groups of primates (24 species). We found that group size and neocortex ratio were correlated with network efficiency. Centralisation (whether several individuals are central in the group) and modularity (how a group is clustered) had opposing effects on network efficiency, showing that tolerant species have more efficient networks. Such network properties affecting individual fitness could be shaped by natural selection. Our results are in accordance with the social brain and cultural intelligence hypotheses, which suggest that the importance of network efficiency and information flow through social learning relates to cognitive abilities. PMID:25534964

Cisco Networking Essentials

CERN Document Server

McMillan, Troy

2011-01-01

An engaging approach for anyone beginning a career in networking As the world leader of networking products and services, Cisco products are constantly growing in demand. Yet, few books are aimed at those who are beginning a career in IT--until now. Cisco Networking Essentials provides a solid foundation on the Cisco networking products and services with thorough coverage of fundamental networking concepts. Author Troy McMillan applies his years of classroom instruction to effectively present high-level topics in easy-to-understand terms for beginners. With this indispensable full-color resour

Computer-communication networks

CERN Document Server

Meditch, James S

1983-01-01

Computer- Communication Networks presents a collection of articles the focus of which is on the field of modeling, analysis, design, and performance optimization. It discusses the problem of modeling the performance of local area networks under file transfer. It addresses the design of multi-hop, mobile-user radio networks. Some of the topics covered in the book are the distributed packet switching queuing network design, some investigations on communication switching techniques in computer networks and the minimum hop flow assignment and routing subject to an average message delay constraint

Epidemics on interconnected networks

Science.gov (United States)

Dickison, Mark; Havlin, S.; Stanley, H. E.

2012-06-01

Populations are seldom completely isolated from their environment. Individuals in a particular geographic or social region may be considered a distinct network due to strong local ties but will also interact with individuals in other networks. We study the susceptible-infected-recovered process on interconnected network systems and find two distinct regimes. In strongly coupled network systems, epidemics occur simultaneously across the entire system at a critical infection strength βc, below which the disease does not spread. In contrast, in weakly coupled network systems, a mixed phase exists below βc of the coupled network system, where an epidemic occurs in one network but does not spread to the coupled network. We derive an expression for the network and disease parameters that allow this mixed phase and verify it numerically. Public health implications of communities comprising these two classes of network systems are also mentioned.

Network effects in railways

DEFF Research Database (Denmark)

Landex, Alex

2012-01-01

Railway operation is often affected by network effects as a change in one part of the network can influence other parts of the network. Network effects occur because the train runs may be quite long and since the railway system has a high degree of interdependencies as trains cannot cross....../overtake each other everywhere in the network. First this paper describes network effects in general (section 1). In section 2 the network effects for trains and how they can be measured by scheduled waiting time is described. When the trains are affected by network effects the passengers are also affected....... Therefore, sections 3 and 4 describe the network effects for passengers and how they can be measured using passenger delay models. Before the concluding remarks in section 6, section 5 discusses how the operation can be improved by examining network effects in the planning process. © 2012 WIT Press....

Networks in Cell Biology

Science.gov (United States)

Buchanan, Mark; Caldarelli, Guido; De Los Rios, Paolo; Rao, Francesco; Vendruscolo, Michele

2010-05-01

Introduction; 1. Network views of the cell Paolo De Los Rios and Michele Vendruscolo; 2. Transcriptional regulatory networks Sarath Chandra Janga and M. Madan Babu; 3. Transcription factors and gene regulatory networks Matteo Brilli, Elissa Calistri and Pietro Lió; 4. Experimental methods for protein interaction identification Peter Uetz, Björn Titz, Seesandra V. Rajagopala and Gerard Cagney; 5. Modeling protein interaction networks Francesco Rao; 6. Dynamics and evolution of metabolic networks Daniel Segré; 7. Hierarchical modularity in biological networks: the case of metabolic networks Erzsébet Ravasz Regan; 8. Signalling networks Gian Paolo Rossini; Appendix 1. Complex networks: from local to global properties D. Garlaschelli and G. Caldarelli; Appendix 2. Modelling the local structure of networks D. Garlaschelli and G. Caldarelli; Appendix 3. Higher-order topological properties S. Ahnert, T. Fink and G. Caldarelli; Appendix 4. Elementary mathematical concepts A. Gabrielli and G. Caldarelli; References.

An Optical Multicast Routing with Minimal Network Coding Operations in WDM Networks

Directory of Open Access Journals (Sweden)

Huanlin Liu

2014-01-01

Full Text Available Network coding can improve the optical multicast routing performance in terms of network throughput, bandwidth utilization, and traffic load balance. But network coding needs high encoding operations costs in all-optical WDM networks due to shortage of optical RAM. In the paper, the network coding operation is defined to evaluate the number of network coding operation cost in the paper. An optical multicast routing algorithm based on minimal number of network coding operations is proposed to improve the multicast capacity. Two heuristic criteria are designed to establish the multicast routing with low network coding cost and high multicast capacity. One is to select one path from the former K shortest paths with the least probability of dropping the multicast maximal capacity. The other is to select the path with lowest potential coding operations with the highest link shared degree among the multiple wavelength disjoint paths cluster from source to each destination. Comparing with the other multicast routing based on network coding, simulation results show that the proposed multicast routing algorithm can effectively reduce the times of network coding operations, can improve the probability of reaching multicast maximal capacity, and can keep the less multicast routing link cost for optical WDM networks.

Network Bandwidth Utilization Forecast Model on High Bandwidth Network

Energy Technology Data Exchange (ETDEWEB)

Yoo, Wucherl; Sim, Alex

2014-07-07

With the increasing number of geographically distributed scientific collaborations and the scale of the data size growth, it has become more challenging for users to achieve the best possible network performance on a shared network. We have developed a forecast model to predict expected bandwidth utilization for high-bandwidth wide area network. The forecast model can improve the efficiency of resource utilization and scheduling data movements on high-bandwidth network to accommodate ever increasing data volume for large-scale scientific data applications. Univariate model is developed with STL and ARIMA on SNMP path utilization data. Compared with traditional approach such as Box-Jenkins methodology, our forecast model reduces computation time by 83.2percent. It also shows resilience against abrupt network usage change. The accuracy of the forecast model is within the standard deviation of the monitored measurements.

Network bandwidth utilization forecast model on high bandwidth networks

Energy Technology Data Exchange (ETDEWEB)

Yoo, Wuchert (William) [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sim, Alex [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2015-03-30

With the increasing number of geographically distributed scientific collaborations and the scale of the data size growth, it has become more challenging for users to achieve the best possible network performance on a shared network. We have developed a forecast model to predict expected bandwidth utilization for high-bandwidth wide area network. The forecast model can improve the efficiency of resource utilization and scheduling data movements on high-bandwidth network to accommodate ever increasing data volume for large-scale scientific data applications. Univariate model is developed with STL and ARIMA on SNMP path utilization data. Compared with traditional approach such as Box-Jenkins methodology, our forecast model reduces computation time by 83.2%. It also shows resilience against abrupt network usage change. The accuracy of the forecast model is within the standard deviation of the monitored measurements.

Software-Defined Networks as a Stage of the Network Technology Evolution

Directory of Open Access Journals (Sweden)

A. A. Krasotin

2013-01-01

Full Text Available The authors of the article focus on the concept of a software defined network. In the beginning, the brief historical account is given concerning software defined networks as a scientific concept, its formation and technological and scientific meaning. The software defined network concept is treated in the article not as the final state-of-the-art in networking, but rather as a possible step and direction in the development of a networking paradigm. The article touches on pros and cons as well of the software defined networking and gives an account of possible stages of development of this technology in the context of other technologies, considering its hybrid with MPLS, as an example. OpenFlow protocol constitutes the main part of the article. The authors further discuss various kinds of existing libraries realizing programmable management routines for a software defined network using OpenFlow. All of these libraries provide API for building modular applications for software defined network management. Touching on practical side of implementation the results of comparative tests of throughput and latency, achieved with these libraries are shown.

Basics of Computer Networking

CERN Document Server

Robertazzi, Thomas

2012-01-01

Springer Brief Basics of Computer Networking provides a non-mathematical introduction to the world of networks. This book covers both technology for wired and wireless networks. Coverage includes transmission media, local area networks, wide area networks, and network security. Written in a very accessible style for the interested layman by the author of a widely used textbook with many years of experience explaining concepts to the beginner.

Thin Watts-Strogatz networks.

Science.gov (United States)

de Moura, Alessandro P S

2006-01-01

A modified version of the Watts-Strogatz (WS) network model is proposed, in which the number of shortcuts scales with the network size N as Nalpha, with alpha infinity, whereas in the original WS model, this ratio is constant. We call such networks "thin Watts-Strogatz networks." We show that even though the fraction of shortcuts becomes vanishingly small for large networks, they still cause a kind of small-world effect, in the sense that the length L of the network increases sublinearly with the size. We develop a mean-field theory for these networks, which predicts that the length scales as N1-alpha ln N for large N. We also study how a search using only local information works in thin WS networks. We find that the search performance is enhanced compared to the regular network, and we predict that the search time tau scales as N1-alpha/2. These theoretical results are tested using numerical simulations. We comment on the possible relevance of thin WS networks for the design of high-performance low-cost communication networks.

"Homeless Networks: Testing Peer and Homed Networks Against Location Choice"

OpenAIRE

Shinichiro Iwata; Koji Karato

2007-01-01

This paper examines the location choices of homeless people in Osaka City, and finds them concentrated because of homeless networks. The paper also shows that different types of homeless networks operate in two different homeless groups: (1) peer networks that provide a social tie inside homeless communities are observed in groups that had not had work experience in the day labor market; (2) homed networks that provide a social tie outside homeless communities affect location choice in the ex...

Networks in ATLAS

CERN Document Server

Mc Kee, Shawn Patrick; The ATLAS collaboration

2016-01-01

Networks have played a critical role in high-energy physics (HEP), enabling us to access and effectively utilize globally distributed resources to meet the needs of our physicists. Because of their importance in enabling our grid computing infrastructure many physicists have taken leading roles in research and education (R&E) networking, participating in, and even convening, network related meetings and research programs with the broader networking community worldwide. This has led to HEP benefiting from excellent global networking capabilities for little to no direct cost. However, as other science domains ramp-up their need for similar networking it becomes less clear that this situation will continue unchanged. What this means for ATLAS in particular needs to be understood. ATLAS has evolved its computing model since the LHC started based upon its experience with using globally distributed resources. The most significant theme of those changes has been increased reliance upon, and use of, its networks....

Networks in ATLAS

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00260714; The ATLAS collaboration

2017-01-01

Networks have played a critical role in high-energy physics (HEP), enabling us to access and effectively utilize globally distributed resources to meet the needs of our physicists. Because of their importance in enabling our grid computing infrastructure many physicists have taken leading roles in research and education (R&E) networking, participating in, and even convening, network related meetings and research programs with the broader networking community worldwide. This has led to HEP benefiting from excellent global networking capabilities for little to no direct cost. However, as other science domains ramp-up their need for similar networking it becomes less clear that this situation will continue unchanged. What this means for ATLAS in particular needs to be understood. ATLAS has evolved its computing model since the LHC started based upon its experience with using globally distributed resources. The most significant theme of those changes has been increased reliance upon, and use of, its networks....

Mobility Models for Next Generation Wireless Networks Ad Hoc, Vehicular and Mesh Networks

CERN Document Server

Santi, Paolo

2012-01-01

Mobility Models for Next Generation Wireless Networks: Ad Hoc, Vehicular and Mesh Networks provides the reader with an overview of mobility modelling, encompassing both theoretical and practical aspects related to the challenging mobility modelling task. It also: Provides up-to-date coverage of mobility models for next generation wireless networksOffers an in-depth discussion of the most representative mobility models for major next generation wireless network application scenarios, including WLAN/mesh networks, vehicular networks, wireless sensor networks, and

Networking for big data

CERN Document Server

Yu, Shui; Misic, Jelena; Shen, Xuemin (Sherman)

2015-01-01

Networking for Big Data supplies an unprecedented look at cutting-edge research on the networking and communication aspects of Big Data. Starting with a comprehensive introduction to Big Data and its networking issues, it offers deep technical coverage of both theory and applications.The book is divided into four sections: introduction to Big Data, networking theory and design for Big Data, networking security for Big Data, and platforms and systems for Big Data applications. Focusing on key networking issues in Big Data, the book explains network design and implementation for Big Data. It exa

A link prediction method for heterogeneous networks based on BP neural network

Science.gov (United States)

Li, Ji-chao; Zhao, Dan-ling; Ge, Bing-Feng; Yang, Ke-Wei; Chen, Ying-Wu

2018-04-01

Most real-world systems, composed of different types of objects connected via many interconnections, can be abstracted as various complex heterogeneous networks. Link prediction for heterogeneous networks is of great significance for mining missing links and reconfiguring networks according to observed information, with considerable applications in, for example, friend and location recommendations and disease-gene candidate detection. In this paper, we put forward a novel integrated framework, called MPBP (Meta-Path feature-based BP neural network model), to predict multiple types of links for heterogeneous networks. More specifically, the concept of meta-path is introduced, followed by the extraction of meta-path features for heterogeneous networks. Next, based on the extracted meta-path features, a supervised link prediction model is built with a three-layer BP neural network. Then, the solution algorithm of the proposed link prediction model is put forward to obtain predicted results by iteratively training the network. Last, numerical experiments on the dataset of examples of a gene-disease network and a combat network are conducted to verify the effectiveness and feasibility of the proposed MPBP. It shows that the MPBP with very good performance is superior to the baseline methods.

Collaborative Multi-Layer Network Coding For Hybrid Cellular Cognitive Radio Networks

KAUST Repository

Moubayed, Abdallah J.

2014-05-01

In this thesis, as an extension to [1], we propose a prioritized multi-layer network coding scheme for collaborative packet recovery in hybrid (interweave and underlay) cellular cognitive radio networks. This scheme allows the uncoordinated collaboration between the collocated primary and cognitive radio base-stations in order to minimize their own as well as each other’s packet recovery overheads, thus by improving their throughput. The proposed scheme ensures that each network’s performance is not degraded by its help to the other network. Moreover, it guarantees that the primary network’s interference threshold is not violated in the same and adjacent cells. Yet, the scheme allows the reduction of the recovery overhead in the collocated primary and cognitive radio networks. The reduction in the cognitive radio network is further amplified due to the perfect detection of spectrum holes which allows the cognitive radio base station to transmit at higher power without fear of violating the interference threshold of the primary network. For the secondary network, simulation results show reductions of 20% and 34% in the packet recovery overhead, compared to the non-collaborative scheme, for low and high probabilities of primary packet arrivals, respectively. For the primary network, this reduction was found to be 12%. Furthermore, with the use of fractional cooperation, the average recovery overhead is further reduced by around 5% for the primary network and around 10% for the secondary network when a high fractional cooperation probability is used.

Organization of complex networks

Science.gov (United States)

Kitsak, Maksim

Many large complex systems can be successfully analyzed using the language of graphs and networks. Interactions between the objects in a network are treated as links connecting nodes. This approach to understanding the structure of networks is an important step toward understanding the way corresponding complex systems function. Using the tools of statistical physics, we analyze the structure of networks as they are found in complex systems such as the Internet, the World Wide Web, and numerous industrial and social networks. In the first chapter we apply the concept of self-similarity to the study of transport properties in complex networks. Self-similar or fractal networks, unlike non-fractal networks, exhibit similarity on a range of scales. We find that these fractal networks have transport properties that differ from those of non-fractal networks. In non-fractal networks, transport flows primarily through the hubs. In fractal networks, the self-similar structure requires any transport to also flow through nodes that have only a few connections. We also study, in models and in real networks, the crossover from fractal to non-fractal networks that occurs when a small number of random interactions are added by means of scaling techniques. In the second chapter we use k-core techniques to study dynamic processes in networks. The k-core of a network is the network's largest component that, within itself, exhibits all nodes with at least k connections. We use this k-core analysis to estimate the relative leadership positions of firms in the Life Science (LS) and Information and Communication Technology (ICT) sectors of industry. We study the differences in the k-core structure between the LS and the ICT sectors. We find that the lead segment (highest k-core) of the LS sector, unlike that of the ICT sector, is remarkably stable over time: once a particular firm enters the lead segment, it is likely to remain there for many years. In the third chapter we study how

Specifying Orchestrating Capability in Network Organization and Interfirm Innovation Networks

DEFF Research Database (Denmark)

Hu, Yimei; Sørensen, Olav Jull

-tech industry. Besides interfirm networks, some organizational researchers are interested in the internal network organizational design. Prospector firms putting innovation on top of the agenda usually has a network organization which is more flexible. This paper analyzes how an SME from a traditional industry...

Network performance of a wireless sensor network for temperature monitoring in vineyards

DEFF Research Database (Denmark)

Liscano, Ramiro; Jacoub, John Khalil; Dersingh, Anand

2011-01-01

Wireless sensor networks (WSNs) are an emerging technology which can be used for outdoor environmental monitoring. This paper presents challenges that arose from the development and deployment of a WSN for environmental monitoring as well as network performance analysis of this network. Different...... components in our sensor network architecture are presented like the physical nodes, the sensor node code, and two messaging protocols; one for collecting sensor and network values and the other for sensor node commands. An information model for sensor nodes to support plug-and-play capabilities in sensor...... networks is also presented....

Influence of choice of null network on small-world parameters of structural correlation networks.

Directory of Open Access Journals (Sweden)

S M Hadi Hosseini

Full Text Available In recent years, coordinated variations in brain morphology (e.g., volume, thickness have been employed as a measure of structural association between brain regions to infer large-scale structural correlation networks. Recent evidence suggests that brain networks constructed in this manner are inherently more clustered than random networks of the same size and degree. Thus, null networks constructed by randomizing topology are not a good choice for benchmarking small-world parameters of these networks. In the present report, we investigated the influence of choice of null networks on small-world parameters of gray matter correlation networks in healthy individuals and survivors of acute lymphoblastic leukemia. Three types of null networks were studied: 1 networks constructed by topology randomization (TOP, 2 networks matched to the distributional properties of the observed covariance matrix (HQS, and 3 networks generated from correlation of randomized input data (COR. The results revealed that the choice of null network not only influences the estimated small-world parameters, it also influences the results of between-group differences in small-world parameters. In addition, at higher network densities, the choice of null network influences the direction of group differences in network measures. Our data suggest that the choice of null network is quite crucial for interpretation of group differences in small-world parameters of structural correlation networks. We argue that none of the available null models is perfect for estimation of small-world parameters for correlation networks and the relative strengths and weaknesses of the selected model should be carefully considered with respect to obtained network measures.

Influence of Choice of Null Network on Small-World Parameters of Structural Correlation Networks

Science.gov (United States)

Hosseini, S. M. Hadi; Kesler, Shelli R.

2013-01-01

In recent years, coordinated variations in brain morphology (e.g., volume, thickness) have been employed as a measure of structural association between brain regions to infer large-scale structural correlation networks. Recent evidence suggests that brain networks constructed in this manner are inherently more clustered than random networks of the same size and degree. Thus, null networks constructed by randomizing topology are not a good choice for benchmarking small-world parameters of these networks. In the present report, we investigated the influence of choice of null networks on small-world parameters of gray matter correlation networks in healthy individuals and survivors of acute lymphoblastic leukemia. Three types of null networks were studied: 1) networks constructed by topology randomization (TOP), 2) networks matched to the distributional properties of the observed covariance matrix (HQS), and 3) networks generated from correlation of randomized input data (COR). The results revealed that the choice of null network not only influences the estimated small-world parameters, it also influences the results of between-group differences in small-world parameters. In addition, at higher network densities, the choice of null network influences the direction of group differences in network measures. Our data suggest that the choice of null network is quite crucial for interpretation of group differences in small-world parameters of structural correlation networks. We argue that none of the available null models is perfect for estimation of small-world parameters for correlation networks and the relative strengths and weaknesses of the selected model should be carefully considered with respect to obtained network measures. PMID:23840672

A method for identifying hierarchical sub-networks / modules and weighting network links based on their similarity in sub-network / module affiliation

Directory of Open Access Journals (Sweden)

WenJun Zhang

2016-06-01

Full Text Available Some networks, including biological networks, consist of hierarchical sub-networks / modules. Based on my previous study, in present study a method for both identifying hierarchical sub-networks / modules and weighting network links is proposed. It is based on the cluster analysis in which between-node similarity in sets of adjacency nodes is used. Two matrices, linkWeightMat and linkClusterIDs, are achieved by using the algorithm. Two links with both the same weight in linkWeightMat and the same cluster ID in linkClusterIDs belong to the same sub-network / module. Two links with the same weight in linkWeightMat but different cluster IDs in linkClusterIDs belong to two sub-networks / modules at the same hirarchical level. However, a link with an unique cluster ID in linkClusterIDs does not belong to any sub-networks / modules. A sub-network / module of the greater weight is the more connected sub-network / modules. Matlab codes of the algorithm are presented.

Distance metric learning for complex networks: Towards size-independent comparison of network structures

Science.gov (United States)

Aliakbary, Sadegh; Motallebi, Sadegh; Rashidian, Sina; Habibi, Jafar; Movaghar, Ali

2015-02-01

Real networks show nontrivial topological properties such as community structure and long-tail degree distribution. Moreover, many network analysis applications are based on topological comparison of complex networks. Classification and clustering of networks, model selection, and anomaly detection are just some applications of network comparison. In these applications, an effective similarity metric is needed which, given two complex networks of possibly different sizes, evaluates the amount of similarity between the structural features of the two networks. Traditional graph comparison approaches, such as isomorphism-based methods, are not only too time consuming but also inappropriate to compare networks with different sizes. In this paper, we propose an intelligent method based on the genetic algorithms for integrating, selecting, and weighting the network features in order to develop an effective similarity measure for complex networks. The proposed similarity metric outperforms state of the art methods with respect to different evaluation criteria.

Cluster-based single-sink wireless sensor networks and passive optical network converged network incorporating sideband modulation schemes

Science.gov (United States)

Kumar, Love; Sharma, Vishal; Singh, Amarpal

2018-02-01

Wireless sensor networks have tremendous applications, such as civil, military, and environmental monitoring. In most of the applications, sensor data are required to be propagated over the internet/core networks, which result in backhaul setback. Subsequently, there is a necessity to backhaul the sensed information of such networks together with prolonging of the transmission link. Passive optical network (PON) is next-generation access technology emerging as a potential candidate for convergence of the sensed data to the core system. Earlier, the work with single-optical line terminal-PON was demonstrated and investigated merely analytically. This work is an attempt to demonstrate a practical model of a bidirectional single-sink wireless sensor network-PON converged network in which the collected data from cluster heads are transmitted over PON networks. Further, modeled converged structure has been investigated under the influence of double, single, and tandem sideband modulation schemes incorporating a corresponding phase-delay to the sensor data entities that have been overlooked in the past. The outcome illustrates the successful fusion of the sensor data entities over PON with acceptable bit error rate and signal to noise ratio serving as a potential development in the sphere of such converged networks. It has also been revealed that the data entities treated with tandem side band modulation scheme help in improving the performance of the converged structure. Additionally, analysis for uplink transmission reported with queue theory in terms of time cycle, average time delay, data packet generation, and bandwidth utilization. An analytical analysis of proposed converged network shows that average time delay for data packet transmission is less as compared with time cycle delay.

Do-it-yourself networks: a novel method of generating weighted networks.

Science.gov (United States)

Shanafelt, D W; Salau, K R; Baggio, J A

2017-11-01

Network theory is finding applications in the life and social sciences for ecology, epidemiology, finance and social-ecological systems. While there are methods to generate specific types of networks, the broad literature is focused on generating unweighted networks. In this paper, we present a framework for generating weighted networks that satisfy user-defined criteria. Each criterion hierarchically defines a feature of the network and, in doing so, complements existing algorithms in the literature. We use a general example of ecological species dispersal to illustrate the method and provide open-source code for academic purposes.

Information theoretic description of networks

Science.gov (United States)

Wilhelm, Thomas; Hollunder, Jens

2007-11-01

We present a new information theoretic approach for network characterizations. It is developed to describe the general type of networks with n nodes and L directed and weighted links, i.e., it also works for the simpler undirected and unweighted networks. The new information theoretic measures for network characterizations are based on a transmitter-receiver analogy of effluxes and influxes. Based on these measures, we classify networks as either complex or non-complex and as either democracy or dictatorship networks. Directed networks, in particular, are furthermore classified as either information spreading and information collecting networks. The complexity classification is based on the information theoretic network complexity measure medium articulation (MA). It is proven that special networks with a medium number of links ( L∼n1.5) show the theoretical maximum complexity MA=(log n)2/2. A network is complex if its MA is larger than the average MA of appropriately randomized networks: MA>MAr. A network is of the democracy type if its redundancy Rdictatorship network. In democracy networks all nodes are, on average, of similar importance, whereas in dictatorship networks some nodes play distinguished roles in network functioning. In other words, democracy networks are characterized by cycling of information (or mass, or energy), while in dictatorship networks there is a straight through-flow from sources to sinks. The classification of directed networks into information spreading and information collecting networks is based on the conditional entropies of the considered networks ( H(A/B)=uncertainty of sender node if receiver node is known, H(B/A)=uncertainty of receiver node if sender node is known): if H(A/B)>H(B/A), it is an information collecting network, otherwise an information spreading network. Finally, different real networks (directed and undirected, weighted and unweighted) are classified according to our general scheme.

Better sales networks.

Science.gov (United States)

Ustüner, Tuba; Godes, David

2006-01-01

Anyone in sales will tell you that social networks are critical. The more contacts you have, the more leads you'll generate, and, ultimately, the more sales you'll make. But that's a vast oversimplification. Different configurations of networks produce different results, and the salesperson who develops a nuanced understanding of social networks will outshine competitors. The salesperson's job changes over the course of the selling process. Different abilities are required in each stage of the sale: identifying prospects, gaining buy-in from potential customers, creating solutions, and closing the deal. Success in the first stage, for instance, depends on the salesperson acquiring precise and timely information about opportunities from contacts in the marketplace. Closing the deal requires the salesperson to mobilize contacts from prior sales to act as references. Managers often view sales networks only in terms of direct contacts. But someone who knows lots of people doesn't necessarily have an effective network because networks often pay off most handsomely through indirect contacts. Moreover, the density of the connections in a network is important. Do a salesperson's contacts know all the same people, or are their associates widely dispersed? Sparse networks are better, for example, at generating unique information. Managers can use three levers--sales force structure, compensation, and skills development--to encourage salespeople to adopt a network-based view and make the best possible use of social webs. For example, the sales force can be restructured to decouple lead generation from other tasks because some people are very good at building diverse ties but not so good at maintaining other kinds of networks. Companies that take steps of this kind to help their sales teams build better networks will reap tremendous advantages.

Unraveling spurious properties of interaction networks with tailored random networks.

Directory of Open Access Journals (Sweden)

Stephan Bialonski

Full Text Available We investigate interaction networks that we derive from multivariate time series with methods frequently employed in diverse scientific fields such as biology, quantitative finance, physics, earth and climate sciences, and the neurosciences. Mimicking experimental situations, we generate time series with finite length and varying frequency content but from independent stochastic processes. Using the correlation coefficient and the maximum cross-correlation, we estimate interdependencies between these time series. With clustering coefficient and average shortest path length, we observe unweighted interaction networks, derived via thresholding the values of interdependence, to possess non-trivial topologies as compared to Erdös-Rényi networks, which would indicate small-world characteristics. These topologies reflect the mostly unavoidable finiteness of the data, which limits the reliability of typically used estimators of signal interdependence. We propose random networks that are tailored to the way interaction networks are derived from empirical data. Through an exemplary investigation of multichannel electroencephalographic recordings of epileptic seizures--known for their complex spatial and temporal dynamics--we show that such random networks help to distinguish network properties of interdependence structures related to seizure dynamics from those spuriously induced by the applied methods of analysis.

Bayesian Network Webserver: a comprehensive tool for biological network modeling.

Science.gov (United States)

Ziebarth, Jesse D; Bhattacharya, Anindya; Cui, Yan

2013-11-01

The Bayesian Network Webserver (BNW) is a platform for comprehensive network modeling of systems genetics and other biological datasets. It allows users to quickly and seamlessly upload a dataset, learn the structure of the network model that best explains the data and use the model to understand relationships between network variables. Many datasets, including those used to create genetic network models, contain both discrete (e.g. genotype) and continuous (e.g. gene expression traits) variables, and BNW allows for modeling hybrid datasets. Users of BNW can incorporate prior knowledge during structure learning through an easy-to-use structural constraint interface. After structure learning, users are immediately presented with an interactive network model, which can be used to make testable hypotheses about network relationships. BNW, including a downloadable structure learning package, is available at http://compbio.uthsc.edu/BNW. (The BNW interface for adding structural constraints uses HTML5 features that are not supported by current version of Internet Explorer. We suggest using other browsers (e.g. Google Chrome or Mozilla Firefox) when accessing BNW). ycui2@uthsc.edu. Supplementary data are available at Bioinformatics online.

Proliferation Networks and Financing

International Nuclear Information System (INIS)

Gruselle, Bruno

2007-01-01

The objective of this study is to propose practical solutions aimed at completing and strengthening the existing arrangement for the control of nuclear proliferation through a control of financial as well as material or immaterial flows. In a first part, the author proposes a systemic analysis of networks of suppliers and demanders. He notably evokes the Khan's network and the Iraqi acquisition network during the 1993-2001 period. He also proposes a modelling of proliferation networks (supplier networks and acquisition networks) and of their interactions. In a second part, the author examines possible means and policies aimed at neutralising proliferation networks: organisation, adaptation and improvement of intelligence tools in front of proliferation networks, and means, limitations and perspectives of network neutralisation. He also briefly addresses the possibility of military action to contain proliferation flows

The correlation of metrics in complex networks with applications in functional brain networks

NARCIS (Netherlands)

Li, C.; Wang, H.; De Haan, W.; Stam, C.J.; Van Mieghem, P.F.A.

2011-01-01

An increasing number of network metrics have been applied in network analysis. If metric relations were known better, we could more effectively characterize networks by a small set of metrics to discover the association between network properties/metrics and network functioning. In this paper, we

Real-time network traffic classification technique for wireless local area networks based on compressed sensing

Science.gov (United States)

Balouchestani, Mohammadreza

2017-05-01

Network traffic or data traffic in a Wireless Local Area Network (WLAN) is the amount of network packets moving across a wireless network from each wireless node to another wireless node, which provide the load of sampling in a wireless network. WLAN's Network traffic is the main component for network traffic measurement, network traffic control and simulation. Traffic classification technique is an essential tool for improving the Quality of Service (QoS) in different wireless networks in the complex applications such as local area networks, wireless local area networks, wireless personal area networks, wireless metropolitan area networks, and wide area networks. Network traffic classification is also an essential component in the products for QoS control in different wireless network systems and applications. Classifying network traffic in a WLAN allows to see what kinds of traffic we have in each part of the network, organize the various kinds of network traffic in each path into different classes in each path, and generate network traffic matrix in order to Identify and organize network traffic which is an important key for improving the QoS feature. To achieve effective network traffic classification, Real-time Network Traffic Classification (RNTC) algorithm for WLANs based on Compressed Sensing (CS) is presented in this paper. The fundamental goal of this algorithm is to solve difficult wireless network management problems. The proposed architecture allows reducing False Detection Rate (FDR) to 25% and Packet Delay (PD) to 15 %. The proposed architecture is also increased 10 % accuracy of wireless transmission, which provides a good background for establishing high quality wireless local area networks.

The Economics of Networking

DEFF Research Database (Denmark)

Sørensen, Olav Jull

The literature on business networks is often oversocialized. The economic side of business is implicitly assumed. This paper analyses the economics of network behavior by loking at each of the key concepts in the Network Theory.......The literature on business networks is often oversocialized. The economic side of business is implicitly assumed. This paper analyses the economics of network behavior by loking at each of the key concepts in the Network Theory....

Software Defined Networking

DEFF Research Database (Denmark)

Caba, Cosmin Marius

Network Service Providers (NSP) often choose to overprovision their networks instead of deploying proper Quality of Services (QoS) mechanisms that allow for traffic differentiation and predictable quality. This tendency of overprovisioning is not sustainable for the simple reason that network...... resources are limited. Hence, to counteract this trend, current QoS mechanisms must become simpler to deploy and operate, in order to motivate NSPs to employ QoS techniques instead of overprovisioning. Software Defined Networking (SDN) represents a paradigm shift in the way telecommunication and data...... generic perspective (e.g. service provisioning speed, resources availability). As a result, new mechanisms for providing QoS are proposed, solutions for SDN-specific QoS challenges are designed and tested, and new network management concepts are prototyped, all aiming to improve QoS for network services...

Manufacturing network evolution

DEFF Research Database (Denmark)

Yang, Cheng; Farooq, Sami; Johansen, John

2011-01-01

Purpose – This paper examines the effect of changes at the manufacturing plant level on other plants in the manufacturing network and also investigates the role of manufacturing plants on the evolution of a manufacturing network. Design/methodology/approach –The research questions are developed...... different manufacturing plants in the network and their impact on network transformation. Findings – The paper highlights the dominant role of manufacturing plants in the continuously changing shape of a manufacturing network. The paper demonstrates that a product or process change at one manufacturing...... by identifying the gaps in the reviewed literature. The paper is based on three case studies undertaken in Danish manufacturing companies to explore in detail their manufacturing plants and networks. The cases provide a sound basis for developing the research questions and explaining the interaction between...

Multifractal analysis of complex networks

International Nuclear Information System (INIS)

Wang Dan-Ling; Yu Zu-Guo; Anh V

2012-01-01

Complex networks have recently attracted much attention in diverse areas of science and technology. Many networks such as the WWW and biological networks are known to display spatial heterogeneity which can be characterized by their fractal dimensions. Multifractal analysis is a useful way to systematically describe the spatial heterogeneity of both theoretical and experimental fractal patterns. In this paper, we introduce a new box-covering algorithm for multifractal analysis of complex networks. This algorithm is used to calculate the generalized fractal dimensions D q of some theoretical networks, namely scale-free networks, small world networks, and random networks, and one kind of real network, namely protein—protein interaction networks of different species. Our numerical results indicate the existence of multifractality in scale-free networks and protein—protein interaction networks, while the multifractal behavior is not clear-cut for small world networks and random networks. The possible variation of D q due to changes in the parameters of the theoretical network models is also discussed. (general)

Comparison of neural network applications for channel assignment in cellular TDMA networks and dynamically sectored PCS networks

Science.gov (United States)

Hortos, William S.

1997-04-01

The use of artificial neural networks (NNs) to address the channel assignment problem (CAP) for cellular time-division multiple access and code-division multiple access networks has previously been investigated by this author and many others. The investigations to date have been based on a hexagonal cell structure established by omnidirectional antennas at the base stations. No account was taken of the use of spatial isolation enabled by directional antennas to reduce interference between mobiles. Any reduction in interference translates into increased capacity and consequently alters the performance of the NNs. Previous studies have sought to improve the performance of Hopfield- Tank network algorithms and self-organizing feature map algorithms applied primarily to static channel assignment (SCA) for cellular networks that handle uniformly distributed, stationary traffic in each cell for a single type of service. The resulting algorithms minimize energy functions representing interference constraint and ad hoc conditions that promote convergence to optimal solutions. While the structures of the derived neural network algorithms (NNAs) offer the potential advantages of inherent parallelism and adaptability to changing system conditions, this potential has yet to be fulfilled the CAP for emerging mobile networks. The next-generation communication infrastructures must accommodate dynamic operating conditions. Macrocell topologies are being refined to microcells and picocells that can be dynamically sectored by adaptively controlled, directional antennas and programmable transceivers. These networks must support the time-varying demands for personal communication services (PCS) that simultaneously carry voice, data and video and, thus, require new dynamic channel assignment (DCA) algorithms. This paper examines the impact of dynamic cell sectoring and geometric conditioning on NNAs developed for SCA in omnicell networks with stationary traffic to improve the metrics

Influence of degree correlations on network structure and stability in protein-protein interaction networks

Directory of Open Access Journals (Sweden)

Zimmer Ralf

2007-08-01

Full Text Available Abstract Background The existence of negative correlations between degrees of interacting proteins is being discussed since such negative degree correlations were found for the large-scale yeast protein-protein interaction (PPI network of Ito et al. More recent studies observed no such negative correlations for high-confidence interaction sets. In this article, we analyzed a range of experimentally derived interaction networks to understand the role and prevalence of degree correlations in PPI networks. We investigated how degree correlations influence the structure of networks and their tolerance against perturbations such as the targeted deletion of hubs. Results For each PPI network, we simulated uncorrelated, positively and negatively correlated reference networks. Here, a simple model was developed which can create different types of degree correlations in a network without changing the degree distribution. Differences in static properties associated with degree correlations were compared by analyzing the network characteristics of the original PPI and reference networks. Dynamics were compared by simulating the effect of a selective deletion of hubs in all networks. Conclusion Considerable differences between the network types were found for the number of components in the original networks. Negatively correlated networks are fragmented into significantly less components than observed for positively correlated networks. On the other hand, the selective deletion of hubs showed an increased structural tolerance to these deletions for the positively correlated networks. This results in a lower rate of interaction loss in these networks compared to the negatively correlated networks and a decreased disintegration rate. Interestingly, real PPI networks are most similar to the randomly correlated references with respect to all properties analyzed. Thus, although structural properties of networks can be modified considerably by degree

An Improved Car-Following Model in Vehicle Networking Based on Network Control

Directory of Open Access Journals (Sweden)

D. Y. Kong

2014-01-01

Full Text Available Vehicle networking is a system to realize information interoperability between vehicles and people, vehicles and roads, vehicles and vehicles, and cars and transport facilities, through the network information exchange, in order to achieve the effective monitoring of the vehicle and traffic flow. Realizing information interoperability between vehicles and vehicles, which can affect the traffic flow, is an important application of network control system (NCS. In this paper, a car-following model using vehicle networking theory is established, based on network control principle. The car-following model, which is an improvement of the traditional traffic model, describes the traffic in vehicle networking condition. The impact that vehicle networking has on the traffic flow is quantitatively assessed in a particular scene of one-way, no lane changing highway. The examples show that the capacity of the road is effectively enhanced by using vehicle networking.

Energy Efficient Digital Networks

Energy Technology Data Exchange (ETDEWEB)

Lanzisera, Steven [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Brown, Richard [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2013-01-01

Digital networks are the foundation of the information services, and play an expanding and indispensable role in our lives, via the Internet, email, mobile phones, etc. However, these networks consume energy, both through the direct energy use of the network interfaces and equipment that comprise the network, and in the effect they have on the operating patterns of devices connected to the network. The purpose of this research was to investigate a variety of technology and policy issues related to the energy use caused by digital networks, and to further develop several energy-efficiency technologies targeted at networks.

computer networks

Directory of Open Access Journals (Sweden)

N. U. Ahmed

2002-01-01

Full Text Available In this paper, we construct a new dynamic model for the Token Bucket (TB algorithm used in computer networks and use systems approach for its analysis. This model is then augmented by adding a dynamic model for a multiplexor at an access node where the TB exercises a policing function. In the model, traffic policing, multiplexing and network utilization are formally defined. Based on the model, we study such issues as (quality of service QoS, traffic sizing and network dimensioning. Also we propose an algorithm using feedback control to improve QoS and network utilization. Applying MPEG video traces as the input traffic to the model, we verify the usefulness and effectiveness of our model.

Visionary network 2030. Technology vision for future distribution network

International Nuclear Information System (INIS)

Kumpulainen, L.; Laaksonen, H.; Komulainen, R.

2006-11-01

Objective of this research was to create the long term vision of a distribution network technology to be used for the near future rebuild and necessary R and D efforts. Present status of the grid was briefly handled and created scenarios for the operational environment changes and available technology International view was used for getting familiar with the present solutions and future expectations in other countries. Centralised power generation is supposed to form the majority, but also the distributed generation will play more and more important role, which is hard to predict due to the uncertainty of the development of the regulation. Higher reliability and safety in major faults are expected from the future network with the reasonable costs. Impact of the climate change and impregnant using restrictions cause difficulties especially for the overhead lines in the forests. In the rural network also the ageing is the problem. For the urban networks the land usage and environmental issues get more challenging and the network reinforcement is necessary due to the increased use of electricity. As a result several technical solutions are available. Additions to the technology today, several new solutions were introduced. Important solutions in the future network are supposed to be the wide range of underground cable, high degree utilisation of the communication and network automation solutions, considerable shorter protection zones and new layout solution. In a long run the islanding enabled by the distributed energy systems and totally new network structures and solutions based on power electronics are supposed to improve the power quality and profitability. Separate quality classes in network design principally are also supposed to be approved. Getting into the vision needs also the Roadmap project, which coordinates and focuses the development of the industry. So the limited national development resources can be effectively utilised. A coordinated national

Spatial analysis of bus transport networks using network theory

Science.gov (United States)

Shanmukhappa, Tanuja; Ho, Ivan Wang-Hei; Tse, Chi Kong

2018-07-01

In this paper, we analyze the bus transport network (BTN) structure considering the spatial embedding of the network for three cities, namely, Hong Kong (HK), London (LD), and Bengaluru (BL). We propose a novel approach called supernode graph structuring for modeling the bus transport network. A static demand estimation procedure is proposed to assign the node weights by considering the points of interests (POIs) and the population distribution in the city over various localized zones. In addition, the end-to-end delay is proposed as a parameter to measure the topological efficiency of the bus networks instead of the shortest distance measure used in previous works. With the aid of supernode graph representation, important network parameters are analyzed for the directed, weighted and geo-referenced bus transport networks. It is observed that the supernode concept has significant advantage in analyzing the inherent topological behavior. For instance, the scale-free and small-world behavior becomes evident with supernode representation as compared to conventional or regular graph representation for the Hong Kong network. Significant improvement in clustering, reduction in path length, and increase in centrality values are observed in all the three networks with supernode representation. The correlation between topologically central nodes and the geographically central nodes reveals the interesting fact that the proposed static demand estimation method for assigning node weights aids in better identifying the geographically significant nodes in the network. The impact of these geographically significant nodes on the local traffic behavior is demonstrated by simulation using the SUMO (Simulation of Urban Mobility) tool which is also supported by real-world empirical data, and our results indicate that the traffic speed around a particular bus stop can reach a jammed state from a free flow state due to the presence of these geographically important nodes. A comparison

The correlation of metrics in complex networks with applications in functional brain networks

International Nuclear Information System (INIS)

Li, C; Wang, H; Van Mieghem, P; De Haan, W; Stam, C J

2011-01-01

An increasing number of network metrics have been applied in network analysis. If metric relations were known better, we could more effectively characterize networks by a small set of metrics to discover the association between network properties/metrics and network functioning. In this paper, we investigate the linear correlation coefficients between widely studied network metrics in three network models (Bárabasi–Albert graphs, Erdös–Rényi random graphs and Watts–Strogatz small-world graphs) as well as in functional brain networks of healthy subjects. The metric correlations, which we have observed and theoretically explained, motivate us to propose a small representative set of metrics by including only one metric from each subset of mutually strongly dependent metrics. The following contributions are considered important. (a) A network with a given degree distribution can indeed be characterized by a small representative set of metrics. (b) Unweighted networks, which are obtained from weighted functional brain networks with a fixed threshold, and Erdös–Rényi random graphs follow a similar degree distribution. Moreover, their metric correlations and the resultant representative metrics are similar as well. This verifies the influence of degree distribution on metric correlations. (c) Most metric correlations can be explained analytically. (d) Interestingly, the most studied metrics so far, the average shortest path length and the clustering coefficient, are strongly correlated and, thus, redundant. Whereas spectral metrics, though only studied recently in the context of complex networks, seem to be essential in network characterizations. This representative set of metrics tends to both sufficiently and effectively characterize networks with a given degree distribution. In the study of a specific network, however, we have to at least consider the representative set so that important network properties will not be neglected

Virtual Networking Performance in OpenStack Platform for Network Function Virtualization

Directory of Open Access Journals (Sweden)

Franco Callegati

2016-01-01

Full Text Available The emerging Network Function Virtualization (NFV paradigm, coupled with the highly flexible and programmatic control of network devices offered by Software Defined Networking solutions, enables unprecedented levels of network virtualization that will definitely change the shape of future network architectures, where legacy telco central offices will be replaced by cloud data centers located at the edge. On the one hand, this software-centric evolution of telecommunications will allow network operators to take advantage of the increased flexibility and reduced deployment costs typical of cloud computing. On the other hand, it will pose a number of challenges in terms of virtual network performance and customer isolation. This paper intends to provide some insights on how an open-source cloud computing platform such as OpenStack implements multitenant network virtualization and how it can be used to deploy NFV, focusing in particular on packet forwarding performance issues. To this purpose, a set of experiments is presented that refer to a number of scenarios inspired by the cloud computing and NFV paradigms, considering both single tenant and multitenant scenarios. From the results of the evaluation it is possible to highlight potentials and limitations of running NFV on OpenStack.

Virtualized Network Control (VNC)

Energy Technology Data Exchange (ETDEWEB)

Lehman, Thomas [Univ. of Southern California, Los Angeles, CA (United States); Guok, Chin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ghani, Nasir [Univ. of New Mexico, Albuquerque, NM (United States)

2013-01-31

The focus of this project was on the development of a "Network Service Plane" as an abstraction model for the control and provisioning of multi-layer networks. The primary motivation for this work were the requirements of next generation networked applications which will need to access advanced networking as a first class resource at the same level as compute and storage resources. A new class of "Intelligent Network Services" were defined in order to facilitate the integration of advanced network services into application specific workflows. This new class of network services are intended to enable real-time interaction between the application co-scheduling algorithms and the network for the purposes of workflow planning, real-time resource availability identification, scheduling, and provisioning actions.

Airborne Network Optimization with Dynamic Network Update

Science.gov (United States)

2015-03-26

source si and a target ti . For each commodity (si, ki) the commodity specifies a non- negative demand di [5]. The objective of the multi-commodity...queue predictions, and network con- gestion [15]. The implementation of the DRQC uses the Kalman filter to predict the state of the network and optimize

Virtual network embedding in cross-domain network based on topology and resource attributes

Science.gov (United States)

Zhu, Lei; Zhang, Zhizhong; Feng, Linlin; Liu, Lilan

2018-03-01

Aiming at the network architecture ossification and the diversity of access technologies issues, this paper researches the cross-domain virtual network embedding algorithm. By analysing the topological attribute from the local and global perspective of nodes in the virtual network and the physical network, combined with the local network resource property, we rank the embedding priority of the nodes with PCA and TOPSIS methods. Besides, the link load distribution is considered. Above all, We proposed an cross-domain virtual network embedding algorithm based on topology and resource attributes. The simulation results depicts that our algorithm increases the acceptance rate of multi-domain virtual network requests, compared with the existing virtual network embedding algorithm.

Packet Tracer network simulator

CERN Document Server

Jesin, A

2014-01-01

A practical, fast-paced guide that gives you all the information you need to successfully create networks and simulate them using Packet Tracer.Packet Tracer Network Simulator is aimed at students, instructors, and network administrators who wish to use this simulator to learn how to perform networking instead of investing in expensive, specialized hardware. This book assumes that you have a good amount of Cisco networking knowledge, and it will focus more on Packet Tracer rather than networking.

Computer network defense system

Science.gov (United States)

Urias, Vincent; Stout, William M. S.; Loverro, Caleb

2017-08-22

A method and apparatus for protecting virtual machines. A computer system creates a copy of a group of the virtual machines in an operating network in a deception network to form a group of cloned virtual machines in the deception network when the group of the virtual machines is accessed by an adversary. The computer system creates an emulation of components from the operating network in the deception network. The components are accessible by the group of the cloned virtual machines as if the group of the cloned virtual machines was in the operating network. The computer system moves network connections for the group of the virtual machines in the operating network used by the adversary from the group of the virtual machines in the operating network to the group of the cloned virtual machines, enabling protecting the group of the virtual machines from actions performed by the adversary.