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1

Swinging Yo-Yo  

NSDL National Science Digital Library

Learners build a pendulum from a yo-yo, and then design their own experiment to determine what affects the pendulum's period of swing. They can alter the mass of the yo-yo by adding play dough, the length of the yo-yo string, or some other variable of their own choosing. Learners collect data and graph their results. This activity starts on p.17 of the manual. This manual contains 4 activities related to the Spectra's Force comic book published by the American Physical Society.

Thompson, Rebecca; Johnson, Kerry G.; Ellis, David; Bennett-Karasik, Nancy

2011-01-01

2

Yo-Yo Pull Demonstration  

ERIC Educational Resources Information Center

A popular demonstration involves placing a yo-yo on a level table and gently pulling the string horizontally when it is wrapped to come out below the center of the yo-yo's axis. Students are then asked to predict which way the yo-yo will move. A similar demonstration is performed with a tricycle by pulling forward on a pedal with the pedal down in…

Layton, William

2013-01-01

3

The Yo-Yo Problem  

NSDL National Science Digital Library

In this math lesson, learners explore linear patterns, write a pattern in symbolic form, and solve linear equations using algebra tiles, symbolic manipulation, and a graphing calculator. The lesson begins with the presentation of the yo-yo problem. Then learners complete a hands-on activity involving a design created with pennies. Algebra tiles are introduced next as learners practice solving linear equations. Finally, learners return to solving the yo-yo problem.

Pbs

2012-01-01

4

Recycled Yo-Yo Challenge  

NSDL National Science Digital Library

In this activity, learners are challenged to build their own yo-yo toys using items found in their recycling bins. Learners search for materials to use for each part of the toy: two discs, an axle, and string. Learners then sketch their invention, assemble the parts, and test it out. Learners are encouraged to tweak their yo-yos and make improvements.

History, National M.

2012-06-26

5

Two-String Yo-Yo  

NSDL National Science Digital Library

Learners build a yo-yo using a piece of wood, PVC pipe, and string. In doing so, learners explore the force of gravity and angular momentum. This activity guide includes step-by-step instructions with images, a video, and focus questions. Drill, hacksaw or jigsaw, and hammer are required.

Workshop, Watsonville E.

2011-01-01

6

Antifungal substances produced by fungal strain Kyu-W63 from wheat leaf and its taxonomic position  

Microsoft Academic Search

Fungal strain Kyu-W63 from a wheat leaf suppressed the development of wheat powdery mildew caused by Blumeria graminis f. sp. tritici. Nuclear magnetic resonance analysis revealed that Kyu-W63 produced two volatile substances: 5-pentyl-2-furaldehyde and 5-(4-pentenyl)-2-furaldehyde. Although the two are known to be nematicidal substances, the antifungal activity of 5-(4-pentenyl)-2-furaldehyde was first confirmed in the present study. Culture experiments revealed that

Motoo Koitabashi; Yuuji Kajitani; Keita Hirashima

2004-01-01

7

?-alanine supplementation improves YoYo intermittent recovery test performance  

PubMed Central

Background ?-alanine supplementation has been shown to improve high-intensity exercise performance and capacity. However, the effects on intermittent exercise are less clear, with no effect shown on repeated sprint activity. The aim of this study was to investigate the effects of ?-alanine supplementation on YoYo Intermittent Recovery Test Level 2 (YoYo IR2) performance. Methods Seventeen amateur footballers were allocated to either a placebo (PLA; N = 8) or ?-alanine (BA; N = 9) supplementation group, and performed the YoYo IR2 on two separate occasions, pre and post 12 weeks of supplementation during a competitive season. Specifically, players were supplemented from early to mid-season (PLA: N = 5; BA: N = 6) or mid- to the end of the season (PLA: N = 3; BA: N = 3). Data were analysed using a two factor ANOVA with Tukey post-hoc analyses. Results Pre supplementation scores were 1185 ± 216 and 1093 ± 148 m for PLA and BA, with no differences between groups (P = 0.41). YoYo performance was significantly improved for BA (+34.3%, P ? 0.001) but not PLA (?7.3%, P = 0.24) following supplementation. 2 of 8 (Early – Mid: 2 of 5; Mid – End: 0 of 3) players improved their YoYo scores in PLA (Range: -37.5 to + 14.7%) and 8 of 9 (Early – Mid: 6 of 6; Mid – End: 2 of 3) improved for BA (Range: +0.0 to +72.7%). Conclusions 12 weeks of ?-alanine supplementation improved YoYo IR2 performance, likely due to an increased muscle buffering capacity resulting in an attenuation of the reduction in intracellular pH during high-intensity intermittent exercise.

2012-01-01

8

The Yo-Yo Problem: Solving Linear Equations  

NSDL National Science Digital Library

In this lesson, students explore linear patterns, write a pattern in symbolic form, and solve linear equations using algebra tiles, symbolic manipulation, and the graphing calculator. The lesson starts with the presentation of the yo-yo problem. Students then complete a hands-on activity involving a design created with pennies that allows them to explore a linear pattern and express that pattern in symbolic form. Algebra tiles are introduced as the students practice solving linear equations. Working from the concrete to the abstract is especially important for students who have difficulty with mathematics, and algebra tiles help students make this transition. In addition to using algebra tiles, students also use symbolic manipulation and the graphing calculator. Finally, the students return to solve the yo-yo problem. A feature of this lesson is the effective use of peer tutors in this inclusion classroom. Student worksheets are included to print.

2007-12-12

9

The application of the Yo-Yo intermittent endurance level 2 test to elite female soccer populations.  

PubMed

The aim of this study was to evaluate the application of the Yo-Yo intermittent endurance test level 2 (Yo-Yo IE2) to elite female soccer populations. Elite senior (n?=?92), youth (n?=?42), domestic (n?=?46) and sub-elite female soccer players (n?=?19) carried out the Yo-Yo IE2 test on numerous occasions across the season. Test-retest coefficient of variation (CV) in Yo-Yo IE2 test performance in domestic female players was 4.5%. Elite senior female players' Yo-Yo IE2 test performances were better (P?Yo-Yo IE2 test performance (P?Yo-Yo IE2 test performance and the total and high-intensity distance covered (r?=?0.55; P?Yo-Yo IE2 test performance and (r?=?0.68; P?Yo-Yo IE2 test were greater (P?Yo-Yo IE2 test performance increased by 14% (P?Yo-Yo IE2 test is reproducible and is an indicator of the match-specific physical capacity of female soccer players. Furthermore, the Yo-Yo IE2 test illustrates sensitivity by differentiating intermittent exercise performance of female players in various competitive levels, stages of the season and playing positions. PMID:22712498

Bradley, P S; Bendiksen, M; Dellal, A; Mohr, M; Wilkie, A; Datson, N; Orntoft, C; Zebis, M; Gomez-Diaz, A; Bangsbo, J; Krustrup, P

2014-02-01

10

The yo-yo intermittent recovery test in junior basketball players according to performance level and age group.  

PubMed

The aim of this study was to evaluate the Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1) ability to discriminate between elite, subelite junior basketball players, and a group of nonathletic healthy male athletes at 3 different age groups (U-14 to U-17). In a cross-sectional design, 119 age-matched participants spread over 3 groups, elite (n = 46), subelite (n = 42) junior basketball players, and nonathletic healthy male athletes (n = 31), were evaluated over a 5-week period. The participants undertook 2 familiarization trials of the Yo-Yo test performance and 3 test sessions on an indoor basketball court. When controlling for the effect of the participants' body mass, the results showed that elite athletes had a significantly higher Yo-Yo performance compared with the subelite athletes (1,271 ± 385 vs. 861 ± 428 m; p < 0.0017; effect size [ES] 1.0 ± 0.35) and the nonathletic group (1,271 ± 385 vs. 738 ± 345 m; p < 0.0017; ES 1.45 ± 0.38). No statistical differences (p > 0.0017; ES from 0.02 to 0.39) were noted between participants' performance levels across age groups. Typical between-performance levels and -age groups differences in the Yo-Yo IR1 were observed. However, when controlling for the effect of the participants' body mass, this study demonstrates that the Yo-Yo test is accurate only to discriminate elite junior basketball players but cannot be used to differentiate the basketball-specific aerobic performance for age. PMID:22076093

Vernillo, Gianluca; Silvestri, Adriano; Torre, Antonio La

2012-09-01

11

Biochemical Responses to Level-1 Yo-Yo Intermittent Recovery Test in Young Tunisian Football Players  

PubMed Central

Purpose The aim of this work was to investigate the metabolic and muscle damage responses after the level-1 Yo-Yo intermittent recovery test (YYIRT) in young football players. Methods Fifteen male football players (17.42 ± 0.2 yrs, 69.91 ± 4.4 kg, 178.64 ± 3.8 cm; mean ± SD) participated in this study. Fasting blood samples for various biochemical parameters (i.e. lactate (Lac), glucose (GLC), triglycerides (Tri), creatine kinase (CK), uric acid (UA)) collected from a forearm vein after 5-min of seated rest and 3-min after the test. Moreover, rating of perceived exertion (RPE) and maximal heart rate during and after the YYIRT were recorded. Results Mean levels of the selected biochemical markers were raised after the YYIRT exercise (P<0.001 for the other markers). Moreover, lipid parameters increased significantly after the test (P<0.01 for Tri and P<0.001 for HDL). Conclusion These findings confirm the higher metabolic demand of aerobic as well as anaerobic metabolism and reflect a significant mobilization of purine cycle during the YYIRT. The increase of muscle damage markers also reflects the higher anaerobic solicitation. From these findings, we can conclude the importance of aerobic and anaerobic metabolism during soccer-specific endurance performance (i.e. YYIRT, soccer match).

Hammouda, Omar; Chtourou, Hamdi; Chaouachi, Anis; Chahed, Henda; Zarrouk, Nidhal; Miled, Abdelhedi; Chamari, Karim; Souissi, Nizar

2012-01-01

12

The Relationship Between the Yo-Yo Tests, Anaerobic Performance and Aerobic Performance in Young Soccer Players  

PubMed Central

The purposes of this study were to determine the relationship between performance in the Yo-Yo intermittent recovery test level 1 (YIRT1), the Yo-Yo intermittent recovery test level 2 (YIRT2) and the Yo-Yo endurance test (continuous) (YET) with maximal oxygen uptake (VO2max) and Wingate anaerobic performance (WaNT) test results in young soccer players (age 15.00 ± 0.0 years, body height 176.3 ± 4.2 cm and body mass 68.1 ± 3.6 kg). An ergospirometry device was used during the treadmill test (TRT) to determine VO2max. At the end of the study, significant differences were found between the Yo-Yo tests and TRT in terms of HRmax (TRT = 195,92, YIRT1 = 197,83, YIRT2 = 198,5 YET = 198) (p > 0.05). While there were moderate correlations between VO2max and YIRT 1–2 performances (respectively, r = 0.56, r = 0.53), there was only a weak relationship between VO2max and YET performance (r = 0.43) (distance covered). There were also moderate significant negative correlations between performance in the YIRT2 and peak power measured in the WaNT (r = ?0.55), although there were no significant correlations between performance in the three tests and average power. A moderate negative correlation was found between performance in the YIRT2 and Fatigue index (FI) (r = ?0,66). In conclusion, the YIRT2 may be a more suitable field test for determining both aerobic and anaerobic performance in soccer players.

Karakoc, Bar?s; Akalan, Cengiz; Alemdaroglu, Utku; Arslan, Ersan

2012-01-01

13

Yo-Yo intermittent recovery test performances within an entire football league during a full season.  

PubMed

The study examined Yo-Yo intermittent recovery level 2 (YYIR2) and submaximal YYIR1 test performances in 172 male semi-professional football players (age; 25.8 ± 4.1 years) representing all teams in a top league at pre-season, start-season, mid-season and end-season. YYIR2 performance was 847 ± 227 m (±SD) at pre-season and rose (P < 0.05) by 128 ± 113 m to 975 ± 205 m at start of season and further (P < 0.05) by 59 ± 102 m to 1034 ± 211 m at mid-season. Submaximal YYIR1 HR was 90.9 ± 4.2% HR(max) at pre-season, which was higher (P < 0.05) than at start, mid and end of season (87.0 ± 3.9, 85.9 ± 4.1 and 87.0 ± 3.7% HR(max), respectively). Peak YYIR2 performance and minimum YYIR1 HR were 1068 ± 193 m and 85.1 ± 3.8% HR(max), respectively, with ~50% of the players peaking at mid-season. Top-teams and middle-teams had higher (P < 0.05) peak YYIR2 scores (1094 ± 205 and 1121 ± 152 m, respectively) than bottom-teams (992 ± 185 m). YYIR2 performance was 16% higher (P < 0.05) and YYIR1 HR was 1.4% HR(max) lower (P < 0.05) for regular players than non-regular players at pre-season and remained lower (P < 0.05) throughout the season. Central defenders had poorer (P < 0.05) YYIR performances compared to other positional roles. In conclusion, YYIR performances are highly variable within a football league over a season and are influenced by league ranking, regularity of competitive play and playing position. PMID:23980570

Mohr, Magni; Krustrup, Peter

2014-01-01

14

Como Lo Hago Yo: Mielomeningocele En Bolivia  

PubMed Central

Introducción: Las malformaciones del tubo neural (MTN) representan la segunda causa más frecuente de anomalías congénitas, luego de las cardiopatías. En este grupo se destaca el mielomeningocele (MMC) por su mayor incidencia, y por ser la más incapacitante y la más compleja entre todas las demás malformaciones del sistema nervioso c`entral (SNC). En Bolivia, como en muchos países de Sudamérica, los bajos niveles socio-culturales y la debilidad en el sistema sanitario, hacen que su incidencia y su morbilidad, sean mayores que en las naciones más desarrolladas. Material y Métodos: Se realizó un estudio retrospectivo y descriptivo de 70 casos de MMC, atendidos por un equipo multidisciplinario en el Hospital Universitario Japonés (HUJ) de Santa Cruz de la Sierra, entre 2008-2011. De ellos, 60 fueron intervenidos quirúrgicamente. Resultados: Se realizaron controles prenatales sólo en 27 mujeres (38.6%), diagnosticándose una disrafia espinal en apenas dos casos (7.4%). La edad de ingreso del MMC en su mayoría fue después de las 24 horas (65.6%), predominando su localización en la región lumbosacra (64.3%). De ellos, 67.2% eran abiertos, presentando un 32.9% un daño neurológico motor parcial mientras que 47.1% tenían paraplejia por debajo de la lesión. De los 70 casos, tres (4.3%) no fueron intervenidos, por presentar defectos congénitos severos o estado general grave. Las principales complicaciones posoperatorias inmediatas fueron: dehiscencia de sutura y/o infección de la herida (16.6%), fístula de líquido cefalorraquídeo (LCR) (10%) e infección del SNC (11.7%). La mortalidad general y postoperatoria fue de 7.1% y 3.3%, respectivamente. Al mes de vida presentaban hidrocefalia un 80% de los pacientes operados, colocándose una derivación ventriculoperitoneal (DVP) de presión media. De 9 pacientes que tuvieron un acompanamiento de dos o más años, seis presentaron una médula anclada, que fueron intervenidas quirúrgicamente. Conclusión: En esta serie, el diagnóstico prenatal del MMC fue ocasional y la derivación al HUJ de los recién nacidos con esta malformación fue generalmente tardía. No hubo predominio de género y la mayoría de los casos presentaron sus lesiones en la región lumbar y lumbosacra. La mortalidad general y postoperatoria fue similar a la reportada en la literatura. Pocos enfermos realizaron controles posteriores al alta hospitalaria. Igual que otros países de Sudamérica, las falencias en el sistema público de salud y el nivel sociocultural, son factores determinantes para un mal pronóstico en estos niños. Por sus múltiples complicaciones, el MMC requiere de una especial atención gubernamental, sobre todo de carácter preventivo mediante el uso de ácido fólico en mujeres fértiles, como también de un equipo profesional multidisciplinario, a fin de realizar un tratamiento adecuado y oportuno. Al mismo tiempo, trabajos multicéntricos en hospitales de América Latina, ayudarán al mejor manejo de estos pacientes.

Dabdoub, Carlos F.; Dabdoub, Carlos B.; Villavicencio, Ramiro; Quevedo, German

2014-01-01

15

Yo antibodies in ovarian and breast cancer patients detected by a sensitive immunoprecipitation technique  

PubMed Central

Onconeural antibodies are found in patients with cancer and are associated with paraneoplastic neurological syndromes (PNS). The objective of the present study was to assess the frequency of Yo antibodies in ovarian and breast cancer using a sensitive immunoprecipitation technique, and to look for any association of Yo antibodies with neurological symptoms and prognostic factors. A multiwell adapted fluid-phase immunoassay using radiolabelled recombinant cerebellar degeneration related protein (cdr2), produced by coupled in vitro transcription/translation was used for the detection of Yo antibodies. This technique combines high specificity and sensitivity with high sample analysing capacity for the antibody in question. Sera or EDTA-blood from 810 ovarian (n = 557) and breast cancer (n = 253) patients were analysed for Yo antibodies by immunoprecipitation, as well as immunofluorescence and immune blots. Two hundred healthy blood donors and sera from 17 patients with paraneoplastic cerebellar degeneration and Yo antibodies served as controls. Immunoprecipitation was more sensitive in detecting Yo antibodies than immunofluorescence and immune blots. The prevalence of Yo antibodies was 13/557 (2·3%) in ovarian cancer and 4/253 (1·6%) in breast cancer using immunoprecipitation. Yo antibodies were not correlated with specific histological subgroups. The Yo index of ovarian cancer patients in FIGO stage IV was higher compared to FIGO stage I-III. The prevalence of Yo antibodies was 3 times higher in patients with stage III breast cancer than in stage I and II. Only 2/17 (11·8%) patients with Yo antibodies detected during the screen of 810 cancer patients had PNS. The results show that the prevalence of Yo antibodies is low in ovarian and breast cancer. Yo antibodies may be associated with advanced cancer, but less often with PNS.

Monstad, S E; Storstein, A; D?rum, A; Knudsen, A; L?nning, P E; Salvesen, H B; Aarseth, J H; Vedeler, C A

2006-01-01

16

The 30-15 Intermittent Fitness Test versus the Yo-Yo Intermittent Recovery Test Level 1: relationship and sensitivity to training.  

PubMed

The aim of the current study was to examine the relationship between performance of the Yo-Yo Intermittent Recovery Test Level 1 (Yo-YoIR1) and the 30-15 Intermittent Fitness Test (30-15IFT) and to compare the sensitivity of both tests to training. Fourteen young soccer players performed both tests before and after an 8-wk training intervention, which included 6 sessions/wk: 2 resistance training sessions, 2 high-intensity interval training sessions after technical training (4 sets of 3:30 min of generic running and small-sided games [4v4] during the first and second 4-wk periods, respectively [90-95% maximal HR], interspersed with 3 min at 60-70% maximal HR), and 2 tactical-only training sessions. There was a large correlation between 30-15IFT and Yo-YoIR1 (r = .75, 90% confidence limits [CL] 0.57;0.86). While within-test percentage changes suggested a greater sensitivity to training for the Yo-YoIR1 (+35%, 90%CL 24;45) than for the 30-15IFT (+7%; 4;10), these changes were similarly rated as almost certain (with chances for greater/similar/lower values after training of 100/0/0 for both tests) and moderate, ie, standardized difference, ES = +1.2 90%CL (0.9;1.5) for Yo-YoIR1 and ES = +1.1 (0.7;1.5) for 30-15IFT. The difference in the change between the 2 tests was clearly trivial (0/100/0, ES = -0.1, 90%CL -0.1;-0.1). Both tests might evaluate slightly different physical capacities, but their sensitivity to training is almost certainly similar. These results also highlight the importance of using standardized differences instead of percentage changes in performance to assess the actual training effect of an intervention. PMID:23475226

Buchheit, Martin; Rabbani, Alireza

2014-05-01

17

The 30-15 intermittent fitness test versus the yo-yo intermittent recovery test level 1: relationship and sensitivity to training.  

PubMed

The aim of the current study was to examine the relationship between performance of the Yo-Yo Intermittent Recovery Test Level 1 (Yo-YoIR1) and the 30-15 Intermittent Fitness Test (30-15IFT) and to compare the sensitivity of both tests to training. Fourteen young soccer players performed both tests before and after an 8-wk training intervention, which included 6 sessions/wk: 2 resistance training sessions, 2 high-intensity interval training sessions after technical training (4 sets of 3:30 min of generic running and small-sided games [4v4] during the first and second 4-wk periods, respectively [90-95% maximal HR], interspersed with 3 min at 60-70% maximal HR), and 2 tactical-only training sessions. There was a large correlation between 30-15IFT and Yo-YoIR1 (r = .75, 90% confidence limits [CL] 0.57;0.86). While within-test percentage changes suggested a greater sensitivity to training for the Yo-YoIR1 (+35%, 90%CL 24;45) than for the 30-15IFT (+7%; 4;10), these changes were similarly rated as almost certain (with chances for greater/similar/lower values after training of 100/0/0 for both tests) and moderate, ie, standardized difference, ES = +1.2 90%CL (0.9;1.5) for Yo-YoIR1 and ES = +1.1 (0.7;1.5) for 30-15IFT. The difference in the change between the 2 tests was clearly trivial (0/100/0, ES = -0.1, 90%CL -0.1;-0.1). Both tests might evaluate slightly different physical capacities, but their sensitivity to training is almost certainly similar. These results also highlight the importance of using standardized differences instead of percentage changes in performance to assess the actual training effect of an intervention. PMID:24755976

Buchheit, Martin; Rabbani, Alireza

2014-05-01

18

Temperate carbonate debrites and short-lived earliest Miocene yo-yo tectonics, eastern Taranaki Basin margin, New Zealand  

NASA Astrophysics Data System (ADS)

This study examines two unconformity-bound earliest Miocene temperate shallow-marine limestones at remote Gibson Beach, western North Island, on the eastern margin of Taranaki Basin, New Zealand's only producing hydrocarbon province. The local geology comprises an upper limestone of up to 6 m of spectacular conglomeratic limestone (rudstone; Papakura Limestone) whose pebble- to boulder-sized clasts were derived from cannibalisation of the lower skeletal limestone (bryomol grainstone; Otorohanga Limestone). Multiple lines of evidence require the Otorohanga Limestone to have been well indurated before erosion and clast generation. Cementation occurred from pressure dissolution of calcitic skeletons at burial depths of probably 400 m or more. Subsequent uplift led to local subaerial exposure and karstification of a fault-block cliffed coastline where physical erosion sourced talus limestone debris onto adjacent high-energy pocket beaches. Storm and/or seismic events periodically triggered mass flows of the limestone clasts offshore onto the contemporary mixed siliciclastic-carbonate shelf as channelised carbonate debrites. Lithification of these Papakura Limestone debrites occurred via pressure dissolution, and required a second burial episode. Karst pinnacles preserved on the eroded upper surface of the Papakura Limestone demand uplift again and erosion in a subaerial setting, before subsequent deep burial by Early Miocene siliciclastic shelf sand and turbidite deposits. Strontium isotope dating of brachiopod fossils suggests the two postulated burial-uplift cycles, involving movements up to 400 ± 100 m, occurred very rapidly within several 100 kyr. Speculative drivers of the yo-yo tectonic events are earliest Miocene movements on the nearby major Taranaki Fault thrust in association with regional changes in subduction tectonics at the Australian-Pacific plate boundary, along with pulsed emplacement of obducted gravity slide deposits (Northland Allochthon) onto northern North Island. The two limestones record a previously undocumented degree of eastern Taranaki Basin margin tectonic mobility relevant to a fuller appreciation of petroleum system development in that basin.

Hood, Steven D.; Nelson, Campbell S.

2012-03-01

19

Purkinje Cell Death After Uptake of Anti-Yo Antibodies in Cerebellar Slice Cultures  

PubMed Central

Paraneoplastic cerebellar degeneration accompanying gynecological and breast cancers is characteristically accompanied by a serum and cerebrospinal fluid (CSF) antibody response, termed “anti-Yo,” which reacts with cytoplasmic proteins of cerebellar Purkinje cells. Because these antibodies interact with cytoplasmic rather than cell surface membrane proteins, their role in causing Purkinje cell death has been questioned. To address this issue, we studied the interaction of anti-Yo antibodies with Purkinje cells in slice (organotypic) cultures of rat cerebellum. We incubated cultures with immunoglobulin G (IgG)–containing anti-Yo antibodies using titers of anti-Yo antibody equivalent to those found in CSF of affected patients. Cultures were then studied in real time and after fixation for potential uptake of antibody and induction of cell death. Anti-Yo antibodies delivered in serum, CSF, or purified IgG were taken up by viable Purkinje cells, accumulated intracellularly, and were associated with cell death. Normal IgG was also taken up by Purkinje cells but did not accumulate and did not affect cell viability. These findings indicate that autoantibodies directed against intracellular Purkinje cell proteins can be taken up to cause cell death and suggest that anti-Yo antibody may be directly involved in the pathogenesis of paraneoplastic cerebellar degeneration.

Greenlee, John E.; Clawson, Susan A.; Hill, Kenneth E.; Wood, Blair L.; Tsunoda, Ikuo; Carlson, Noel G.

2010-01-01

20

Time-sliced ion-velocity imaging study of the reaction Y + O2 ? YO + O.  

PubMed

The oxidation reaction dynamics of the gas-phase yttrium atoms by oxygen molecules was studied under crossed-beam conditions. The product YO was detected using a time-of-flight mass spectrometer combined with laser single-photon ionization. An acceleration lens system designed for the ion-velocity mapping conditions, a two-dimensional (2-D) detector, and a time-slicing technique were used to obtain the velocity and angular distributions of the products. Two ionization wavelengths were used for the internal (vibrational and/or electronic) energy selective detection of YO. The single photon of the shorter wavelength (202.0 nm) can ionize all states of YO(X?(2)?, A'?(2)?, and A?(2)?), while electronically excited YO(A' and A) are dominantly ionized at a longer wavelength (285.0 nm). Time-sliced images were converted to the velocity and angular distributions in the center-of-mass frame. The general features of the velocity distributions of YO, determined at two wavelengths, were well represented by those expected from the statistical energy disposal model. The forward-backward symmetry was also observed for two images. These results suggest that the reaction proceeds via long-lived intermediates, and that this mechanism is consistent with previous chemiluminescence/LIF studies. PMID:21423981

Honma, Kenji; Matsumoto, Yoshiteru

2011-05-14

21

Thermodynamic Modeling of the YO(l.5)-ZrO2 System  

NASA Technical Reports Server (NTRS)

The YO1.5-ZrO2 system consists of five solid solutions, one liquid solution, and one intermediate compound. A thermodynamic description of this system is developed, which allows calculation of the phase diagram and thermodynamic properties. Two different solution models are used-a neutral species model with YO1.5 and ZrO2 as the components and a charged species model with Y(+3), Zr(+4), O(-2), and vacancies as components. For each model, regular and sub-regular solution parameters are derived fiom selected equilibrium phase and thermodynamic data.

Jacobson, Nathan S.; Liu, Zi-Kui; Kaufman, Larry; Zhang, Fan

2003-01-01

22

Evaluation of Hybrid-III 6YO ATD Chest Jacket Shape and Position.  

National Technical Information Service (NTIS)

In previous work, belt fit on the Hybrid-III six-year-old (6YO) anthropomorphic test device (ATD) was found to depend on the positioning of the chest jacket of the ATD. Moreover, differences were noted between jackets manufactured by Denton-ATD and First ...

M. P. Reed S. M. Ebert-Hamilton

2011-01-01

23

An Overview of Language Preservation at Ohi: Yo'., the Seneca Allegany Territory  

ERIC Educational Resources Information Center

This project seeks to discover and disseminate information pertaining to the language practices and values of a selected group of "Onodowa'ga:'" (Seneca) at "Ohi:yo'", or the Allegany Territory, in upstate New York. The goal is to find where the current practices and values are situated in the larger picture of Seneca preservation as well as the…

Borgia, Melissa E.

2010-01-01

24

Development, Characterization and Photocatalytic Activities of BiYO3 Nanoparticles under Visible Light Irradiation  

NASA Astrophysics Data System (ADS)

BiYO3 photocatalysts were successfully synthesized as nanoparticles by sol-gel technique. The powder obtained after the calcination of the polymeric precursor at 600 °C was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis and transmission electron microscopy (TEM). The XRD analysis revealed that the synthesized material has a cubic perovskite (ABO3) structure. The particle size calculated from FWHM was ~13 nm. TEM analysis confirmed the nanoscale (10-20 nm) nature of the powder. FT-IR and EDX analyses have shown that the calcined powder is phase pure. UV-vis diffuse reflectance spectroscopy revealed that the crystalline BiYO3 had a band gap of 2.95 eV. This indicated that BiYO3 might perform well as a photocatalyst in the visible light region. Photocatalytic activity of BiYO3 nanoparticles was investigated for the degradation of methyl orange under visible light irradiation.

Kumar, V. Ratheesh; Wariar, P. R. S.; Prasad, V. S.; Koshy, J.

2011-10-01

25

Determination of yttrium using YO band head obtained by laser enhanced ionization spectrometry.  

National Technical Information Service (NTIS)

The determination of yttrium (Y) in water in the concentration range of 2 (mu)g/ml to 200 (mu)g/ml by laser enhanced ionisation (LEI) technique is reported. The YO band head at 584.27 nm belonging to A(sup 2)(Pi) - X(sup 2) (Sigma)(sup +) system is used f...

S. S. Deshpande P. P. Khanna

1997-01-01

26

Laser enhanced ionisation spectrometry of ScO, YO and LaO.  

National Technical Information Service (NTIS)

Laser enhanced ionisation (LEI) spectra of ScO, YO and LaO in the flame have been recorded using excimer laser pumped dye laser with the oxides of scandium, yttrium and lanthanum aspirated in the air - acetylene flame. The LEI spectra of all the three spe...

P. P. Khanna S. S. Deshpande S. A. Ahmad

1997-01-01

27

Development of a new tow-yo instrument to observe detailed river plume structures  

NASA Astrophysics Data System (ADS)

Field observations in coastal and estuary area are important factors in revealing physical and biological structures. However, detailed fine scale structures are difficult to observe in situ due to lack of a suitable instrument. We have developed a new Tow-Yo instrument, Yoing Ocean Data Acquisition Profiler (YODA) to observe the small scale features of coastal waters directly. The high-resolution data obtained from YODA showed fine scale complicated internal wave structures and patchily distribution of phytoplankton along a river plume (Fig.1). We have also developed a scheme to estimate the rate of turbulent kinetic energy dissipation ? from dC/dz signals obtained from YODA. We will present various observed fine scale events. Also we present that a critical angle theory for low frequency internal wave is consistent with our observation.; Fig.1 Salinity and fluorescence distribution around the river mouth obtained from YODA.

Masunaga, E.; Yamazaki, H.; Nagai, T.

2012-12-01

28

New chrodrimanin congeners, chrodrimanins D-H, from YO-2 of Talaromyces sp.  

PubMed

Four new meroterpenoids, named chrodrimanins D-G (4-7), and one known compound, renamed chrodrimanin H (8), were isolated from okara (the insoluble residue of whole soybean) that had been fermented with the YO-2 strain of Talaromyces sp. Their structures were elucidated by spectroscopic methods. Chrodrimanins D (4), E (5), and F (6) showed insecticidal activity against silkworms with respective LD(50) values of 20, 10, and 50 µg/g of diet. PMID:22972343

Hayashi, Hideo; Oka, Yuki; Kai, Kenji; Akiyama, Kohki

2012-01-01

29

A new meroterpenoid, chrodrimanin C, from YO-2 of Talaromyces sp.  

PubMed

The new meroterpenoid, chrodrimanin C (3), together with chrodrimanins A (2) and B (1) were isolated from okara (the insoluble residue of whole soybean) that had been fermented with strain YO-2 of Talaromyces sp. Their structures were elucidated by spectroscopic methods. The partial structures of 1 essential for exhibiting insecticidal activity were investigated by using a silkworm assay. The absolute configuration of 1 was also determined. PMID:22484942

Hayashi, Hideo; Oka, Yuki; Kai, Kenji; Akiyama, Kohki

2012-01-01

30

Networking.  

ERIC Educational Resources Information Center

Networking is an information giving and receiving system, a support system, and a means whereby women can get ahead in careers--either in new jobs or in current positions. Networking information can create many opportunities: women can talk about how other women handle situations and tasks, and previously established contacts can be used in…

Duvall, Betty

31

Yo, Hamlet!  

ERIC Educational Resources Information Center

This article presents Alan Sitomer, an English teacher at Lynwood High School, and how he teaches his students classic literature through hip-hop. These at-risk students attend a severely overcrowded, low-performing school in East Los Angeles that's surrounded by what Sitomer describes as "gangs, guns, and drugs." Prostitutes work the streets just…

Whelan, Debra Lau

2007-01-01

32

Fluorescence spectra of laser-excited YO molecules in a H2-O2Ar flame  

Microsoft Academic Search

CW dye laser induced fluorescence emission and thermal emission spectra of YO-molecules in a 1 atm H2---O2---Ar flame of 2430 K were recorded simultaneously. Narrow band laser excitation was applied to four rotational lines in the (1, 1) Q-branch of the A2?3\\/2?X2?+ transition and broadband excitation was applied to several separate Q-branches of the A2?1\\/2,3\\/2?X2?+ transitions. From the differences between

T. Wijchers; H. A. Dijkerman; P. J. Th. Zeegers; C. Th. J. Alkemade

1980-01-01

33

Network  

Microsoft Academic Search

In the first issue this year (volume 8, issue 1), Network profiled self-employment support programmes offered by Business Ability and East Lancs into Employment. In this, the final issue of the year, we look at another self-employment scheme, operated by West Norfolk MIND - one that demonstrates how much can be achieved by seizing local opportunities, despite quite limited resources.

Adam Pozner

2004-01-01

34

A new tow-yo instrument to observe high-resolution coastal phenomena  

NASA Astrophysics Data System (ADS)

Field observations in coastal and estuarine regions are important for studying physical and biological features. Recent studies have presented fine-scale physical features from numerical models and acoustic surveys. However, high spatial resolution data of physical structures are difficult to obtain, since the conventional CTD survey requires a stop-and-measure ship operation. To solve this issue, we have developed a new, portable tow-yo instrument, Yoing Ocean Data Acquisition Profiler (YODA Profiler), that continuously observes many vertical profiles of the fine-scale features in coastal regions. Using the YODA Profiler, we were able to rapidly obtain high-resolution data in a shallow estuary. The results showed fine-scale complicated internal wave features, upslope propagating fronts and a patchy distribution of phytoplankton. These observations are consistent with recent numerical models and acoustic surveys, as well as with the critical angle theory for internal wave reflections along a bottom slope. We have also developed a statistical technique to estimate the rate of turbulent kinetic energy dissipation, ?, from the variance of dC/dz data. Using this technique we were able to estimate the turbulent kinetic energy dissipation rate associated with river outflow and internal waves in the river mouth.

Masunaga, Eiji; Yamazaki, Hidekatsu

2014-01-01

35

Anti-Yo Associated Paraneoplastic Cerebellar Degeneration in a Man with Large Cell Cancer of the Lung  

PubMed Central

Purkinje cell cytoplasmic antibody type 1 (PCA-1), or anti-Yo, is the most frequently detected autoantibody in paraneoplastic cerebellar degeneration (PCD). The vast majority of cases of anti-Yo PCD, however, occur in females over 60 years old and are associated with gynecologic tumors. Only 10 cases have been reported in males, and only 2 were associated with cancer of the lung. Here we describe the youngest known case of PCA-1 positive PCD in a male, whose lung tumor was undetectable even on FDG-PET.

Lee, James; Wang, Bonnie H.; Yekkirala, Lalitha

2013-01-01

36

Characteristics of Gd xM yO z (M = Ti, Zr or Al) as a burnable absorber  

NASA Astrophysics Data System (ADS)

A heterogeneous type burnable absorber needs a diluent material to adjust its gadolinium concentration. TiO 2, ZrO 2 or Al 2O 3 was added to Gd 2O 3, separately and Gd xM yO z (M = Ti, Zr or Al) pellets were fabricated by a powder process. Pellets with a single Gd 2TiO 5 or Gd 2Ti 2O 7 were fabricated and their phases were confirmed by XRD. Thermal properties of the Gd xM yO z were measured and their thermal conductivities were determined. The thermal expansion was largest in Gd 2Ti 2O 7, and it decreased with a gadolinium concentration increase. GdAlO 3 had the highest thermal conductivity, next were the Gd xTi yO z phases in a reverse order of the gadolinium concentration increase. The selected candidate pellets of Gd xTi yO z were irradiated in the HANARO reactor, and post-irradiation examinations of the pellets were carried out in a hot cell. The examination results indicate that the thermal properties of the BP pellets should be considered to ensure an in-reactor integrity.

Kim, Han Soo; Joung, Chang Yong; Lee, Byung Ho; Kim, Si Hyung; Sohn, Dong Seong

2008-01-01

38

Increasing High School Students' Interest in STEM Education through Collaborative Brainstorming with Yo-Yos  

ERIC Educational Resources Information Center

Brainstorming is a creativity technique in which a group of people (or an individual person) spontaneously generates a set of ideas to find the solution to a particular problem. This paper describes an innovative approach called "brainstorming with yo-yos," which was implemented in an outreach to high school event to increase high school…

Fang, Ning

2013-01-01

39

Thermodynamic Database for the NdO(1.5)-YO(1.5) -YbO(1.5)-ScO(1.5)-ZrO2 System.  

National Technical Information Service (NTIS)

A database for YO(1.5)-NdO(1.5) -YbO(1.5)-ScO(1.5)-ZrO2 for ThermoCalc (ThermoCalc AB, Stockholm, Sweden) has been developed. The basis of this work is the YO(1.5)-ZrO2 assessment by Y. Du, Z. Jin, and P. Huang, 'Thermodynamic Assessment of the ZrO2-YO(1....

E. H. Copland L. Kaufman N. S. Jacobson

2001-01-01

40

A novel polyaspartate precursor method for the synthesis of LiCayMn2-yO4 nanoparticles for Li-ion batteries  

NASA Astrophysics Data System (ADS)

Cubic spinel LiCayMn2-yO4 nanoparticles were synthesized using nitrates of Li+, Ca2+ and acetate of Mn2+ with aspartic acid as a polymerizable combustion fuel. They were dissolved in distilled water and then concentrated by heating to form a viscous resin which was transformed into a foam-like mass by drying at 120 °C. Phase pure LiCayMn2-yO4 powders were obtained by combustion of these foams. The decomposition temperature of the polyaspartate precursor was investigated by TG/DTA analysis. The structural property of the synthesized LiCayMn2-yO4 powders was confirmed by x-ray diffraction studies. The average particle size of the synthesized powders was calculated from the x-ray data using the Scherrer equation. TEM analysis was also carried out to confirm the particle size and surface morphology of the synthesized LiCayMn2-yO4 powder. Finally, electrochemical charge-discharge studies were carried out by assembling 2016 type electrochemical button cells using carbon as the anode and the synthesized LiCayMn2-yO4 as the cathode with microporous polymer electrolyte.

Subramania, A.; Angayarkanni, N.; Niruba, N.; Vasudevan, T.

2007-02-01

41

A comparison between a child-size PMHS and the Hybrid III 6 YO in a sled frontal impact  

PubMed Central

As pediatric PMHS data are extremely limited, evidence of kinematic differences between pediatric ATDs and live humans comes from comparison of laboratory data to field crash data. Despite the existence of regulations intended to prevent head injuries, these remain the most common serious injuries sustained by children in crashes. In this study, nine frontal sled tests using a Hybrid III 6YO and three tests performed with a child-size adult PMHS were compared, with focus on the kinematic responses (especially of the head) and the seatbelt forces generated during the impact. Two different restraint systems (a pretensioning, force-limiting seatbelt, and a non pretensioning force-limiting standard belt) and two different impact speeds (29 km/h and 48 km/h) were compared. Data from the PMHS were scaled using the erect sitting height of a 50th percentile 6YO and both scaled and unscaled data are presented. The ATD predicted correctly the peak values of the scaled displacements of the PMHS, but differences in relevant parameters such as torso angle and resultant acceleration at different locations were found between the dummy and the PMHS. The ATD’s stiffer thoracic spine is hypothesized as a major cause of these differences.

Lopez-Valdes, Francisco J.; Forman, Jason; Kent, Richard; Bostrom, Ola; Segui-Gomez, Maria

2009-01-01

42

A comparison between a child-size PMHS and the Hybrid III 6 YO in a sled frontal impact.  

PubMed

As pediatric PMHS data are extremely limited, evidence of kinematic differences between pediatric ATDs and live humans comes from comparison of laboratory data to field crash data. Despite the existence of regulations intended to prevent head injuries, these remain the most common serious injuries sustained by children in crashes. In this study, nine frontal sled tests using a Hybrid III 6YO and three tests performed with a child-size adult PMHS were compared, with focus on the kinematic responses (especially of the head) and the seatbelt forces generated during the impact. Two different restraint systems (a pretensioning, force-limiting seatbelt, and a non pretensioning force-limiting standard belt) and two different impact speeds (29 km/h and 48 km/h) were compared. Data from the PMHS were scaled using the erect sitting height of a 50th percentile 6YO and both scaled and unscaled data are presented. The ATD predicted correctly the peak values of the scaled displacements of the PMHS, but differences in relevant parameters such as torso angle and resultant acceleration at different locations were found between the dummy and the PMHS. The ATD's stiffer thoracic spine is hypothesized as a major cause of these differences. PMID:20184847

Lopez-Valdes, Francisco J; Forman, Jason; Kent, Richard; Bostrom, Ola; Segui-Gomez, Maria

2009-10-01

43

Biochemical properties of a novel and highly thermostable bacterial ?-carbonic anhydrase from Sulfurihydrogenibium yellowstonense YO3AOP1.  

PubMed

A new carbonic anhydrase (CA, EC 4.2.1.1) from the thermophilic bacterium Sulfurihydrogenibium yellowstonense YO3AOP1 was identified and characterized. The bacterial carbonic anhydrase gene was expressed in Escherichia coli yielding an active enzyme, which was purified in large amounts. The recombinant protein (SspCA) was found to belong to the ?-CA class and displays esterase activity. The kinetic parameters were determined by using CO(2) and p-nitrophenylacetate (p-NpA) as substrates. The bacterial enzyme presented specific activity comparable to that of bovine carbonic anhydrase (bCA II) but it showed biochemical properties never observed for the mammalian enzyme. The thermophilic enzyme, in fact, was endowed with high thermostability and with unaltered residual activity after prolonged exposure to heat up to 100°C. SspCA and the bovine carbonic anhydrase (bCA II) were immobilized within a polyurethane (PU) foam. The immobilized bacterial enzyme was found to be active and stable at 100°C up to 50 h. PMID:22803664

Capasso, Clemente; De Luca, Viviana; Carginale, Vincenzo; Cannio, Raffaele; Rossi, Mosè

2012-12-01

44

CeO 2–YO 1.5–NdO 1.5 system: An extensive phase relation study  

Microsoft Academic Search

The sub-solidus phase relations in the CeO2–YO1.5–NdO1.5 system have been studied. About 45 compositions in the series Ce1?x(Y0.70Nd0.30)xO2?0.5x, Y1?x(Ce0.50Nd0.50)xO1.5+0.25x and Nd1?x(Ce0.55Y0.45)xO1.5+0.275x were prepared and characterized by powder XRD. In the Ce1?x(Y0.70Nd0.30)xO2?0.5x series, there was a gradual transformation from the defective F-type cubic lattice to an ordered C-type phase with increasing x, whereas in the Y1?x(Ce0.50Nd0.50)xO1.5+0.25x series, the C-type cubic lattice

V. Grover; S. V. Chavan; P. Sengupta; A. K. Tyagi

2010-01-01

45

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: First-principle study of native defects in CuScO2 and CuYO2  

NASA Astrophysics Data System (ADS)

This paper studies the electronic structure and native defects in transparent conducting oxides CuScO2 and CuYO2 using the first-principle calculations. Some typical native copper-related and oxygen-related defects, such as vacancy, interstitials, and antisites in their relevant charge state are considered. The results of calculation show that, CuMO2(M = Sc, Y) is impossible to show n-type conductivity ability. It finds that copper vacancy and oxygen interstitial have relatively low formation energy and they are the relevant defects in CuScO2 and CuYO2. Copper vacancy is the most efficient acceptor, and under O-rich condition oxygen antisite also becomes important acceptor and plays an important role in p-type conductivity.

Fang, Zhi-Jie; Shi, Li-Jie; Liu, Yong-Hui

2008-11-01

46

Hydrogen induced tunnel emission in Pt\\/(BaxSr1-x)Ti1+yO3+z\\/Pt thin film capacitors  

Microsoft Academic Search

The leakage current density-applied field (J-EA) characteristics of (BaxSr1-x)Ti1+yO3+z (BSTO) thin film capacitors with Pt electrodes that have been annealed in forming gas (95% Ar 5% H2 or D2) were investigated over the temperature range from -60 to +60 °C. Forming gas annealing significantly increased the leakage current density. The J-EA characteristics exhibited features that could not be fully explained

J. D. Baniecki; R. B. Laibowitz; T. M. Shaw; C. Parks; J. Lian; H. Xu; Q. Y. Ma

2001-01-01

47

Optical planar and channel waveguides in the new nonlinear crystal Ca4YO(BO3)3 (YCOB) fabricated by He+ implantation.  

PubMed

We report the first study of optical planar and channel waveguides fabricated in the new nonlinear crystal Ca4YO(BO3) by use of MeV He+-implantations. The nx, ny, and nz refractive index modifications are studied. Losses in nonannealed YCOB waveguides measured with a CCD camera are found to be less than 2 dB cm(-1). This work is the first step toward the investigation of frequency conversion within the obtained guiding structures. PMID:14735968

Boudrioua, Azzedine; Vincent, Brice; Moretti, Paul; Tascu, Sorine; Jacquier, Bernard; Aka, Gérard

2004-01-10

48

Thermodynamic Database for the NdO(1.5)-YO(1.5)-YbO(1.5)-ScO(1.5)-ZrO2 System  

NASA Technical Reports Server (NTRS)

A database for YO(1.5)-NdO(1.5)-YbO(1.5)-ScO(1.5)-ZrO2 for ThermoCalc (ThermoCalc AB, Stockholm, Sweden) has been developed. The basis of this work is the YO(1.5)-ZrO2 assessment by Y. Du, Z. Jin, and P. Huang, 'Thermodynamic Assessment of the ZrO2-YO(1.5) System'. Experimentally only the YO(1.5)-ZrO2 system has been well-studied. All other systems are only approximately known. The major simplification in this work is the treatment of each single cation unit as a component. The pure liquid oxides are taken as reference states and two term lattice stability descriptions are used for each of the components. The limited experimental phase diagrams are reproduced.

Jacobson, Nathan S.; Copland, Evan H.; Kaufman, Larry

2001-01-01

49

Preparation of 15 mol% YO 1.5-doped ThO 2 disk electrolytes by a polymeric gel-combustion method  

NASA Astrophysics Data System (ADS)

A hybrid of polymeric gel and auto-combustion techniques was adapted for the synthesis and lower temperature sintering of 15 mol% YO 1.5-doped thoria (15 YDT) homogeneous solid solutions at 1350°C. The YDT discs so prepared were of density better than 99% theoretical and the cubic cell parameter was ao=558.15(±0.13) pm in close agreement with 557.8 pm recently reported as high quality data in JCPDS confirming the validity of the anion vacancy model for Th 0.85Y 0.15O 1.925.

Arul Antony, S.; Nagaraja, K. S.; Sreedharan, O. M.

2001-06-01

50

Composition and structure of acid leached LiMn 2-yTi yO 4 (0.2? y?1.5) spinels  

NASA Astrophysics Data System (ADS)

Lithium manganese titanium spinels, LiMn 2-yTi yO 4, (0.2? y?1.5) have been synthesized by solid-state reaction between TiO 2 (anatase), Li 2CO 3 and MnCO 3. Li + was leached from the powdered reaction products by treatment in excess of 0.2 N HCl at 85 °C for 6 h, under reflux. The elemental composition of the acidic solution and solid residues of leaching has been determined by complexometric titration, atomic absorption spectroscopy and X-ray fluorescence analysis. Powder X-ray diffraction was used for structural characterization of the crystalline fraction of the solid residues. It has been found that the amount of Li + leached from LiMn 2-yTi yO 4 decreases monotonically with increasing y in the interval 0.2? y?1.0 and abruptly drops to negligibly small values for y>1.0. The content of Mn and Li in the liquid phase and of Mn and Ti in the solid (amorphous plus crystalline) residue, were related to the composition and cation distribution in the pristine compounds. A new formal chemical equation describing the process of leaching and a mechanism of the structural transformation undergone by the initial solids as a result of Li + removal has been proposed.

Avdeev, Georgi; Amarilla, José Manuel; Rojo, José María; Petrov, Kostadin; Rojas, Rosa María

2009-12-01

51

Spawning networks  

Microsoft Academic Search

The deployment of new network architectures, services, and protocols is often manual, ad hoc, and time-consuming. We introduce “spawning networks,” a new class of programmable networks that automate the life cycle process for the creation, deployment, and management of network architectures. These networks are capable of spawning distinct “child” virtual networks with their own transport, “parent's” network resources and in

Andrew T. Campbell; Daniel A. Villela; John B. Vicente; H. G. De Meer; K. Miki; Kalai S. Kalaichelvan

1999-01-01

52

Impaired default network functional connectivity in autosomal dominant Alzheimer disease  

PubMed Central

Objective: To investigate default mode network (DMN) functional connectivity MRI (fcMRI) in a large cross-sectional cohort of subjects from families harboring pathogenic presenilin-1 (PSEN1), presenilin-2 (PSEN2), and amyloid precursor protein (APP) mutations participating in the Dominantly Inherited Alzheimer Network. Methods: Eighty-three mutation carriers and 37 asymptomatic noncarriers from the same families underwent fMRI during resting state at 8 centers in the United States, United Kingdom, and Australia. Using group-independent component analysis, fcMRI was compared using mutation status and Clinical Dementia Rating to stratify groups, and related to each participant's estimated years from expected symptom onset (eYO). Results: We observed significantly decreased DMN fcMRI in mutation carriers with increasing Clinical Dementia Rating, most evident in the precuneus/posterior cingulate and parietal cortices (p < 0.001). Comparison of asymptomatic mutation carriers with noncarriers demonstrated decreased fcMRI in the precuneus/posterior cingulate (p = 0.014) and right parietal cortex (p = 0.0016). We observed a significant interaction between mutation carrier status and eYO, with decreases in DMN fcMRI observed as mutation carriers approached and surpassed their eYO. Conclusion: Functional disruption of the DMN occurs early in the course of autosomal dominant Alzheimer disease, beginning before clinically evident symptoms, and worsening with increased impairment. These findings suggest that DMN fcMRI may prove useful as a biomarker across a wide spectrum of disease, and support the feasibility of DMN fcMRI as a secondary endpoint in upcoming multicenter clinical trials in Alzheimer disease.

Chhatwal, Jasmeer P.; Schultz, Aaron P.; Johnson, Keith; Benzinger, Tammie L.S.; Jack, Clifford; Ances, Beau M.; Sullivan, Caroline A.; Salloway, Stephen P.; Ringman, John M.; Koeppe, Robert A.; Marcus, Daniel S.; Thompson, Paul; Saykin, Andrew J.; Correia, Stephen; Schofield, Peter R.; Rowe, Christopher C.; Fox, Nick C.; Brickman, Adam M.; Mayeux, Richard; McDade, Eric; Bateman, Randall; Fagan, Anne M.; Goate, Allison M.; Xiong, Chengjie; Buckles, Virginia D.; Morris, John C.

2013-01-01

53

Networking Standards.  

National Technical Information Service (NTIS)

The enterprise network is currently a multivendor environment consisting of many defacto and proprietary standards. During the 1990s, these networks will evolve towards networks which are based on international standards in both Local Area Network (LAN) a...

M. Davies

1991-01-01

54

Second spin-density wave phase in metallic V2-yO3 close to the metal-insulator transition  

NASA Astrophysics Data System (ADS)

We have observed two spin-density wave phases in hole-doped metallic V2-yO3, one evolves from the other as a function of doping, pressure, or temperature. They differ in their response to an external magnetic field, which can also induce a transition between them. The phase boundary between these two states in the temperature-, doping-, and pressure-dependent phase diagram has been determined by magnetization and magnetotransport measurements. One phase exists at high doping level and has already been described in the literature. The second phase is found in a small parameter range close to the boundary to the antiferromagnetic insulating phase. The quantum-phase transitions between these states as a function of pressure and doping and the respective metamagnetic behavior observed in these phases are discussed in the light of structurally induced changes of the band structure.

Klimm, S.; Herz, M.; Horny, R.; Obermeier, G.; Klemm, M.; Horn, S.

2001-11-01

55

Programmable Networks  

Microsoft Academic Search

Abstract Anumber,of important,innovations are creating a paradigm,shift in networking,leading tohigher,levels of network ,programmability. These innovations include the separation between transmission hardware and control software, availability of open programmable,network ,interfaces and ,the accelerated ,virtualization of networking infrastructure. The ability to rapidly create, deploy and manage new network services in response to user demands,is a key factor driving the programmable,networking,research community. The

Andrew T. Campbell; David Wetherall; Raj Yavatkar

2002-01-01

56

Network Cosmology  

PubMed Central

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.

Krioukov, Dmitri; Kitsak, Maksim; Sinkovits, Robert S.; Rideout, David; Meyer, David; Boguna, Marian

2012-01-01

57

Network Cosmology  

NASA Astrophysics Data System (ADS)

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.

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

2012-11-01

58

Network cosmology.  

PubMed

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. PMID:23162688

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

2012-01-01

59

Raman spectroscopy characterization of actinide oxides (U 1-yPu y)O 2: Resistance to oxidation by the laser beam and examination of defects  

NASA Astrophysics Data System (ADS)

Structural changes in four (U 1-yPu y)O 2 materials with very different plutonium concentrations (0 ? y ? 1) and damage levels (up to 110 dpa) were studied by Raman spectroscopy. The novel experimental approach developed for this purpose consisted in using a laser beam as a heat source to assess the reactivity and structural changes of these materials according to the power supplied locally by the laser. The experiments were carried out in air and in water with or without hydrogen peroxide. As expected, the material response to oxidation in air depends on the plutonium content of the test oxide. At the highest power levels U 3O 8 generally forms with UO 2 whereas no significant change in the spectra indicating oxidation is observed for samples with high plutonium content ( 239PuO 2). Samples containing 25 wt.% plutonium exhibit intermediate behavior, typified mainly by a higher-intensity 632 cm -1 peak and the disappearance of the 1LO peak at 575 cm -1. This can be attributed to the presence of anion sublattice defects without any formation of higher oxides. The range of materials examined also allowed us to distinguish partly the chemical effects of alpha self-irradiation. The results obtained with water and hydrogen peroxide (a water radiolysis product) on a severely damaged 238PuO 2 specimen highlight a specific behavior, observed for the first time.

Jégou, C.; Caraballo, R.; Peuget, S.; Roudil, D.; Desgranges, L.; Magnin, M.

2010-10-01

60

Electrical and magnetic properties of nanosized Mg0.2Mn0.5Ni0.3AlyFe2-yO4 ferrites  

NASA Astrophysics Data System (ADS)

Electrical and magnetic behavior of Mg0.2Mn0.5Ni0.3AlyFe2-yO4(y=0.0-0.3) spinel ferrites synthesized by citrate precursor method sintered at 1200°C are reported. Samples were characterized by X-ray diffraction technique at room temperature. Lattice parameter `a', saturation magnetization Ms, retentivity Mr, Bohr magneton nB and remnant ratio R=Mr/Ms are seen to decrease whereas coercivity Hc shows increasing trend with increasing Al3+ content. Anisotropy field HKA increases with aluminium content, which along with Ms enable calculation of magneto-crystalline anisotopy constant K1, which increases with increasing Al3+ content. The compositional variations of hysteresis parameters like Ms, Hc, Mr and R reveals that grains in composition studied are of multidomain type. A significant reduction in value of initial permeability and relative loss factor (RLF) was observed with increase of Al3+ ions. DC electrical resistivity decreases with increase in temperature exhibiting semiconductor like behavior. Activation energy is determined from dc electrical resistivity measurements. High dc resistivity and very low RLF makes these ferrites suitable particularly for high-frequency applications where eddy current losses are required to be low.

Verma, Satish; Chand, Jagdish; Kumar, Pawan; Singh, M.

2012-06-01

61

Structural Study of the Rhombohedral Fluorite-Related RIII Phase U 1- yLa yO 2±' x, 0.56 ? y ? 0.67  

NASA Astrophysics Data System (ADS)

The structural relationships between the RIII phase, existing in the UO 3-UO 2-LaO 1.5 system for the compositional range U 1- yLa yO 2± x (0.56 ? y ? 0.67), and the fluorite structure have been definitely established by means of electron diffraction. The determination of the structure has been carried out using both X-ray and neutron powder diffraction. The RIII phase constitutes a partially cation-ordered fluoride-related structure, where La and U/La layers alternate along [III] c. The rhombohedral lattice, in its hexagonal setting, is related to the cubic fluorite substructure by the relations a H = {1}/{2}a C - {1}/{2}b C, b H = {1}/{2}b C - {1}/{2}c C, c H = 2(a C + b C + c C). The space group ( R3¯ m), cell parameters aH ? 3.9 Å and c H ? 18.9 Å, and the refined structure show that the RIII phase can be considered as isomorphous to the CaUO 4 structure.

Rojas, R. M.; Herrero, P.; Chain, P. J. García.; Rodriguez-Carvajal, J.

1994-10-01

62

Protein intake during the period of complementary feeding and early childhood and the association with body mass index and percentage body fat a t7yo f age 1-3  

Microsoft Academic Search

Background: A high protein intake during infancy and early child- hood has been proposed to increase the risk of subsequent obesity. Objective: We analyzed the association of different protein intakes during 6-24 mo with body mass index (BMI; in kg\\/m2) and per- centage body fat (%BF) a t7yo fage. Design: The analyses included 203 participants of the DOrtmund Nutritional and

Anke LB Gunther; Anette E Buyken; Anja Kroke

63

Early protein intake and later obesity risk: which protein sources at which time points throughout infancy and childhood are important for body mass index and body fat percentage a t7yo fage?1-3  

Microsoft Academic Search

Background: A high early protein intake has been proposed to increase obesity risk. Objective: We examined whether a critical period of protein intake for later obesity may exist early in childhood and investigated the relation between protein intake from different sources and body mass index SD score and body fat percentage (BF%) a t7yo fage. Design:Thestudypopulationincluded203participantsoftheDort- mundNutritionalandLongitudinallyDesignedStudywithinforma- tion on diet

Anke LB; Thomas Remer Gunther; Anja Kroke; Anette E Buyken

64

Network Solutions.  

ERIC Educational Resources Information Center

This special section explains the latest developments in networking technologies, profiles school districts benefiting from successful implementations, and reviews new products for building networks. Highlights include ATM (asynchronous transfer mode), cable modems, networking switches, Internet screening software, file servers, network management…

Vietzke, Robert; And Others

1996-01-01

65

Computer Networks As Social Networks  

Microsoft Academic Search

Computer networks are inherently social networks, linking people, organizations, and knowledge. They are social institutions that should not be studied in isolation but as integrated into everyday lives. The proliferation of computer networks has facilitated a deemphasis on group solidarities at work and in the community and afforded a turn to networked societies that are loosely bounded and sparsely knit.

Barry Wellman

2001-01-01

66

Semantic Networks and Social Networks  

ERIC Educational Resources Information Center

Purpose: To illustrate the need for social network metadata within semantic metadata. Design/methodology/approach: Surveys properties of social networks and the semantic web, suggests that social network analysis applies to semantic content, argues that semantic content is more searchable if social network metadata is merged with semantic web…

Downes, Stephen

2005-01-01

67

X-ray diffraction, 57Fe Mössbauer and step potential electrochemical spectroscopy study of LiFe yCo 1- yO 2 compounds  

NASA Astrophysics Data System (ADS)

With the aim of finding new cathode materials for lithium-ion batteries, the synthesis of layered solid solutions with LiFe yCo 1- yO 2 stoichiometries has been studied in this work. X-ray single phase products were obtained by a ceramic procedure for 0? y?0.2. The unit cell dimensions of the powdered solids increase with the iron content. The Rietveld analysis of a sample with y=0.1 using anisotropic thermal parameters led to RBRAGG=3.37. The hexagonal unit cell parameters of this solid were a=2.8271(1) Å and c=14.1266(7) Å. The site occupancy used in the Rietveld procedure was: (Fe T0.0086) 6c[Li 0.9868Fe O0.0046] 3b[Li 0.0132Co 0.9000Fe O0.0868] 3aO 2 according to the intensity of the signals observed in the Mössbauer spectrum. This consists of one intense (87%) quadrupole split signal with isomer shift of ca. 0.316(3) mm/s is ascribable to Fe(III) replacing cobalt in the CoO 2 layers. Two weaker quadrupole signals result from small amounts of iron in octahedral 3b and pseudotetrahedral 6c sites of the LiO 2 layers. The presence of pseudotetrahedral iron puts obstacles to the lithium ion diffusivity. In consequence, the electrochemical spectra evidence an increased cell polarization as increases. The lithium extraction at the end of the first charge decreases with iron content, with a maximum of 0.6 Li per formula for y=0.1. The introduction of nickel in the composition of these solids may be useful to improve the electrochemical performance of the solid solutions. Ternary systems show an improved electrochemical behaviour.

Alcántara, R.; Jumas, J. C.; Lavela, P.; Olivier-Fourcade, J.; Pérez-Vicente, C.; Tirado, J. L.

68

Network Anomography  

Microsoft Academic Search

Anomaly detection is a first and important step needed to resp ond to unexpected problems and to assure high performance and se- curity in IP networks. We introduce a framework and a power- ful class of algorithms for network anomography, the problem of inferring network-level anomalies from widely available data ag- gregates. The framework contains novel algorithms, as well as

Yin Zhang; Zihui Ge; Albert G. Greenberg; Matthew Roughan

2005-01-01

69

Como Lo Hago Yo: Myelomeningocele  

PubMed Central

Fortificación con ádico fólico es efectiva, pero aún falta conciencia en los jóvenes. La legalidad del aborto aumenta la importancia de la consulta prenatal. Realizo la cirugía bajo microcoscopio por razones didácticas. Irrigación continua para reducir la temperatura del tejido. Trato a la plaqueta como tejido viable. No suturo la plaqueta. No cierro músculo. ATB por una semana después de cirugía. Hidrocefalia: Válvula en todos los casos de ventriculomegalia. Médula anclada: Desanclar una sola vez. Chiari II: Revisar la válvula. Incluir en el seguimiento rendimiento escolar, puede indicar obstrucción de la válvula o médula anclada.

Lazareff, Jorge

2014-01-01

70

YO.V.A. 2010  

Microsoft Academic Search

\\u000a “Young” is quite an elastic term. architects may still apply this quality to themselves when most other people are on the\\u000a brink of midlife crisis. only at around age 50, a widespread prejudice asserts, will architects be experienced enough to do\\u000a full justice to the exigencies of their profession.

Christian Kühn

71

Start Networking!  

NSDL National Science Digital Library

To get a better understanding of complex networks, students create their own, real social network example by interacting with their peers in the classroom and documenting the interactions. They represent the interaction data as a graph, calculate two mathematical quantities associated with the graphâthe degree of each node and the degree distribution of the graphâand analyze how these quantities can be used to infer properties of the social network at hand.

Complex Systems Science Laboratory

72

Innovation Networks  

NASA Astrophysics Data System (ADS)

The idea for this book started when we organized a topical workshop entitled "Innovation Networks - New Approaches in Modeling and Analyzing" (held in Augsburg, Germany in October 2005), under the auspices of Exystence, a network of excellence funded in the European Union's Fifth Framework Program. Unlike other conferences on innovation and networks, however, this workshop brought together scientists from economics, sociology, communication science, science and technology studies, and physics. With this book we aim to build further on a bridge connecting the bodies of knowledge on networks in economics, the social sciences and, more recently, statistical physics.

Pyka, Andreas; Scharnhorst, Andrea

73

Visualizing networks.  

PubMed

An interrelated set of genes or proteins can be represented effectively as a network that describes physical interactions, regulatory relationships, or metabolic pathways. Visualizing a network can be a helpful method to extract biological meaning and to generate testable hypotheses about large-scale biological data. This chapter describes some potential rationales for visualizing networks of microarray and other data types, which can be integrated and filtered to show potentially significant relationships. It also presents a practical introduction to Osprey and Cytoscape, two software platforms that are powerful tools for visualizing, integrating, and manipulating networks. PMID:16939803

Bell, George W; Lewitter, Fran

2006-01-01

74

Workshop on neural networks  

Microsoft Academic Search

The topics covered in this report are: Learning, Memory, and Artificial Neural Systems; Emerging Neural Network Technology; Neural Networks; Digital Signal Processing and Neural Networks; Application of Neural Networks to In-Core Fuel Management; Neural Networks in Process Control; Neural Network Applications in Image Processing; Neural Networks for Multi-Sensor Information Fusion; Neural Network Research in Instruments Controls Division; Neural Networks Research

R. E. Uhrig; M. L. Emrich

1990-01-01

75

Optical networking: technology and network management for WDM networks  

Microsoft Academic Search

Summary form only given. Optical networks present unique challenges for both network element design and network management. This talk discusses technological and management approaches to WDM issues such as channel-dependent behavior, transparency requirements, and network layering considerations

J. Gamelin; M. Maeda

1996-01-01

76

Traveling Networks  

NSDL National Science Digital Library

In this geometry activity, learners explore networks painted on playgrounds, such as a four square court, and draw their own. Learners walk on every edge until they return to the starting point without walking on any edge more than once. In doing so, learners explore odd and even points (also called nodes), edges, and possible and impossible networks.

Exploratorium

2010-01-01

77

Correction Networks  

Microsoft Academic Search

We consider the problem of sorting sequences obtained from a sorted sequence of n keys by changing the values of at most k keys at some unknown positions. Since even for k=1 a lower bound ?(log n) on the number of parallel comparison steps applies, any comparator network solving this problem cannot be asymptotically faster than the AKS sorting network.

Marcin Kik; Miroslaw Kutylowski; Marek Piotrów

1999-01-01

78

Wavelet networks  

Microsoft Academic Search

A wavelet network concept, which is based on wavelet transform theory, is proposed as an alternative to feedforward neural networks for approximating arbitrary nonlinear functions. The basic idea is to replace the neurons by `wavelons', i.e., computing units obtained by cascading an affine transform and a multidimensional wavelet. Then these affine transforms and the synaptic weights must be identified from

Q. Zhang; A. Benveniste

1992-01-01

79

Network Security  

NSDL National Science Digital Library

This course provides an introduction to the principles and practice of network security. Topics include: security threats in networks, principles for providing security mechanisms (cryptography, key management, message authentication), practice of securing systems (PGP, IPsec, SSL), and recent research topics in security.

Xue, Yuan

2009-02-25

80

Temporal networks  

NASA Astrophysics Data System (ADS)

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, but does not attempt to unify related terminology-rather, we want to make papers readable across disciplines.

Holme, Petter; Saramäki, Jari

2012-10-01

81

Network Simulation  

SciTech Connect

A detailed introduction to the design, implementation and use of network simulation tools is presented. The requirements and issues faced in the design of simulators for wired and wireless networks are discussed. Abstractions such as packet- and fluid-level network models are covered. Several existing simulations are given as examples, with details and rationales regarding design decisions presented. Issues regarding performance and scalability are discussed in detail, describing how one can utilize distributed simulation methods to increase the scale and performance of a simulation environment. Finally, a case study of two simulation tools is presented that have been developed using distributed simulation techniques. This text is essential to any student, researcher or network architect desiring a detailed understanding of how network simulation tools are designed, implemented, and used.

Fujimoto, Richard [ORNL; Perumalla, Kalyan S [ORNL; Riley, George F. [Georgia Institute of Technology

2006-01-01

82

Mapping Semantic Networks to Undirected Networks  

Microsoft Academic Search

Abstract—There exists an injective, information-preserving func- tion that maps,a semantic network (i.e a directed labeled network) to a directed network (i.e. a directed unlabeled network). The edge label in the semantic network is represented as a topological feature of the directed network. Also, there exists an injective function that maps a directed network to an undirected network (i.e. an undirected

Marko A. Rodriguez

2008-01-01

83

Network Engineering for Complex Belief Networks  

Microsoft Academic Search

Developing a large belief network, like any large system, requires systems engineering to manage the design and construction process. We propose that network engineering follow a rapid prototyping approach to network construction. We describe criteria for identifying network modules and the use of 'stubs' within a belief network. We propose an object oriented representation for belief networks which captures the

Suzanne M. Mahoney; Kathryn B. Laskey

1996-01-01

84

Network Topologies  

NSDL National Science Digital Library

Network topology is the physical arrangement of the switching devices of a network connecting a group of computers or buildings. This brief interactive activity, by the Electromechanical Digital Library and Wisconsin Technical College System faculty, explains how and why these connections are made. It showcases common topologies including mesh, bus, star, and ring topologies. Users can click through these various categories at their own speed, replaying animations and rereading explanations as many times as the individual needs. This is a great resource for students and teachers alike to familiarize themselves with network topologies. [ES

Bartelt, Terry L.

2009-04-30

85

On Networking.  

National Technical Information Service (NTIS)

This paper focuses on the theoretical and practical problems inherent in trying to build, create, develop, enhance, or strengthen networks among persons, groups, or organizations that would be useful in educational change efforts. The concepts of 'social ...

M. B. Miles

1977-01-01

86

Network specialist  

NSDL National Science Digital Library

Teachers can direct students to this material to help them investigate a career as a network specialist. Having students review this page can be an excellent precursor to a job-shadowing activity. This set of questions and answers can be a helpful resource for an activity in which students produce a number of pertinent questions that should be asked of a network specialist when investigating this field of work.

Project, Iowa P.

2002-01-01

87

Autonomic Networking in Wireless Sensor Networks  

Microsoft Academic Search

In this chapter, we address autonomic networking in termsof wireless sensor networks (WSNs), a typical example of wirelessnetworks\\u000a in pervasive computing. In order to investigate the stateof the art of autonomic networking in sensor networks and its futureprospects,\\u000a we start with a short summary of autonomic networking andSensor networks. It follows the discussion of the appliance ofautonomic\\u000a networking in WSNs

Mengjie Yu; Hala Mokhtar; Madjid Merabti

88

Isothermal Sections and Primary Crystallization in the Quasiternary YO 1.5-BaO-CuO x System at p(O 2) = 0.21 × 10 5 Pa  

NASA Astrophysics Data System (ADS)

The phase relations along the sections Y 2BaCuO 5-CuO x and YBa 2Cu 3O 7-?-CuO x at temperatures between 900 and 1100°C at 0.21 × 10 5 Pa O 2 pressure have been investigated by DTA/TG and soaking experiments. Peritectic reaction temperatures have been observed to be 960°C and 940°C, respectively. The results have been combined with literature data to construct a consistent set of isothermal sections in the quasiternary YO 1.5-BaO-CuO x system. A precondition of this consideration is the occurrence of only one type of melt which expands over wide ranges of the triangle as the temperature increases. The primary crystallization fields of solid phases have been derived.

Krabbes, G.; Bieger, W.; Wiesner, U.; Ritschel, M.; Teresiak, A.

1993-04-01

89

Microstructural Characterization of the Fluorite Phase in the U-La-O System. II. Hexagonal Microdomain Formation in (U 1- yLa y)O 2- x, 0.70 ? y ? 0.80  

NASA Astrophysics Data System (ADS)

Fluorite-type materials ( U1-yLa y)O 2- x within the compositional range 0.70 ? y ? 0.80 have been characterized by X-ray diffraction and transmission electron microscopy. Their microstructures are discussed in terms of microdomain formation of a secondary phase, denominated RII coherently intergrown with the fluorite matrix. Annealing of the materials y = 0.73 and y = 0.74 at 1100°C for 500 hr leads to the formation of the RII phase as a single phase, which may be described as a superstructure 2a c × 2a c × 3a c of the fluorite cell. A new set of lattice parameters has been determined on the basis of a primitive trigonal cell, being ah = 0.78220(4) nm and ch = 0.99712(7) nm for the composition y = 0.74. Relationships between the fluorite and the R II cells are presented.

Garcia-Chain, P.; Rojas, R. M.; Herrero, P.; Günter, J. R.

1994-02-01

90

Mixed conductivity and Mössbauer spectra of (La 0.5Sr 0.5) 1-xFe 1-yAl yO 3-? ( x=0-0.05, y=0-0.30)  

NASA Astrophysics Data System (ADS)

Aluminum incorporation in the rhombohedrally distorted perovskite lattice of (La 0.5Sr 0.5) 1-xFe 1-yAl yO 3-? ( x=0-0.05, y=0-0.30) decreases the unit cell volume and partial ionic and p-type electronic conductivities, while the oxygen nonstoichiometry and thermal expansion at 900-1200 K increase on doping. The creation of A-site cation vacancies has an opposite effect on the transport properties of Al-substituted ceramics. The maximum A-site deficiency tolerated by the (La,Sr)(Fe,Al)O 3-? structure is however limited, close to 3-4%. The Mössbauer spectroscopy revealed progressive localization of electron holes and a mixed charge-compensation mechanism, which results in higher average oxidation state of iron when Al 3+ concentration increases. The average thermal expansion coefficients of (La 0.5Sr 0.5) 1-xFe 1-yAl yO 3-? are (12.2-13.0)×10 -6 K -1 at 300-900 K and (20.1-30.0)×10 -6 K -1 at 900-1200 K in air. The steady-state oxygen permeability (OP) of dense Al-containing membranes is determined mainly by the bulk ionic conductivity. The ion transference numbers at 973-1223 K in air, calculated from the oxygen permeation and faradaic efficiency (FE) data, vary in the range 1×10 -4-3×10 -3, increasing with temperature.

Kharton, Vladislav V.; Waerenborgh, Joao C.; Viskup, Alexander P.; Yakovlev, Sergey O.; Patrakeev, Mikhail V.; Gaczy?ski, Piotr; Marozau, Ivan P.; Yaremchenko, Aleksey A.; Shaula, Aliaksandr L.; Samakhval, Victor V.

2006-04-01

91

Network security.  

PubMed

As you can see, there are a number of different ways to protect your network with different protocols, all of which can be very confusing to people whose core business process is not technology. This article is only a brief synopsis of the dangers that lurk in the corners of the technology world. Therefore, the best course of action is to do as much research as possible rather than falling into a situation of risk and vulnerability by implementing a system or network that does not work with your business. Remember, the technology is there to support your business; the business should not have to work around the technology. PMID:16579273

Chang, Kyle

2006-01-01

92

Principal Networks  

PubMed Central

Graph representations of brain connectivity have attracted a lot of recent interest, but existing methods for dividing such graphs into connected subnetworks have a number of limitations in the context of neuroimaging. This is an important problem because most cognitive functions would be expected to involve some but not all brain regions. In this paper we outline a simple approach for decomposing graphs, which may be based on any measure of interregional association, into coherent “principal networks”. The technique is based on an eigendecomposition of the association matrix, and is closely related to principal components analysis. We demonstrate the technique using cortical thickness and diffusion tractography data, showing that the subnetworks which emerge are stable, meaningful and reproducible. Graph-theoretic measures of network cost and efficiency may be calculated separately for each principal network. Unlike some other approaches, all available connectivity information is taken into account, and vertices may appear in none or several of the subnetworks. Subject-by-subject “scores” for each principal network may also be obtained, under certain circumstances, and related to demographic or cognitive variables of interest.

Clayden, Jonathan D.; Dayan, Michael; Clark, Chris A.

2013-01-01

93

Geography Network  

NSDL National Science Digital Library

The Geography Network bills itself as "a global network . . . [that] provides the infrastructure needed to facilitate the sharing of geographic information between data providers, service providers, and users around the world." With a roster of some two dozen participating members that includes both private firms and government agencies, the site allows access to a wide variety of geographic materials, including basic maps as well as more sophisticated map data intended for use with GIS software. A tool called the Geography Network Explorer allows users to browse the maps and data by publisher or content, or to search the collection by location, type of content, and/or data theme. Some of the maps are designed for dynamic viewing online, with zoom-in capabilities and other features, while other static map images are available for download. The site also offers a discussion forum and a map exchange service, as well as instructions for providers who wish to include their own geographic information in the network. Both serious users of GIS information and more casual map buffs are likely to find this site interesting and useful.

94

Network Views  

ERIC Educational Resources Information Center

The world changed in 2008. The financial crisis brought with it a deepening sense of insecurity, and the desire to be connected to a network increased. Throughout the summer and fall of 2008, events were unfolding with alarming rapidity. The Massachusetts Institute of Technology (MIT) Alumni Association wanted to respond to this change in the…

Alexander, Louis

2010-01-01

95

Network synthesis  

NASA Technical Reports Server (NTRS)

A discussion, with numerous examples, on the application of state variable methods to network analysis and synthesis is reported. The state variable point of view is useful in the design of control circuits for regulators because, unlike frequency domain methods, it is applicable to linear and nonlinear problems. The reported are intended as an introduction to this theory.

Brockett, R. W.

1975-01-01

96

Network opportunity  

NASA Astrophysics Data System (ADS)

Our developing scientific understanding of complex networks is being usefully applied in a wide set of financial systems. What we've learned from the 2008 crisis could be the basis of better management of the economy -- and a means to avert future disaster.

Catanzaro, Michele; Buchanan, Mark

2013-03-01

97

Networked Services  

Microsoft Academic Search

In order to create the agile and adaptive force needed to enable NCW and EBO concepts, the force needs to be conceived as components that can be rapidly assembled to provide mission capability packages to meet the commander's need. Previous work in this area has focussed on information exchanges. This paper proposes broadening our approach to consider 'networked services' as

Daniel Hall; Ruth Gani; Neill Smith; Lan Dong; Thea Clark; Gina Kingston; Jon Bell; DSTO Russell

98

Knowledge Networks  

ERIC Educational Resources Information Center

The blogosphere and the Internet are both examples of complex, self-organizing networks. So too is the world of academic publishing. Some faculty members are prolific article and book writers. Their publications often are hubs, or even superhubs, in the scholarly literature, cited regularly by others. Some scholars might just be nodes, with…

McLeod, Scott

2008-01-01

99

Workshop on neural networks.  

National Technical Information Service (NTIS)

The topics covered in this report are: Learning, Memory, and Artificial Neural Systems; Emerging Neural Network Technology; Neural Networks; Digital Signal Processing and Neural Networks; Application of Neural Networks to In-Core Fuel Management; Neural N...

R. E. Uhrig M. L. Emrich

1990-01-01

100

Working with neural networks  

Microsoft Academic Search

As explanation of how neural networks operate is given. Programming of neural networks and regular computers is compared. Matching a neural network to an application is discussed. Designing and training a neural network is examined

D. Hammerstrom

1993-01-01

101

Network Management Survey.  

ERIC Educational Resources Information Center

A study was made of management practices in different computer networks. The five networks were chosen as typical of different approaches to network implementation and management: Defense Advanced Research Projects Agency (ARPA) Network, MERIT Network, Triangle Universities Computation Center (TUCC), Oregon State Regional Network, and Tymnet (a…

Cotton, Ira W.

102

Ambient network composition  

Microsoft Academic Search

Ambient networks, a product of a European union sixth framework project, is a novel networking paradigm for beyond 3G. It aims at the ubiquitous provisioning of existing and new services over any access technology and any type of network. Network composition is a core feature of ambient networks. It enables on-demand and transparent cooperation between heterogeneous networks, with little or

Fatna Belqasmi; Roch H. Glitho; Rachida Dssouli

2008-01-01

103

Securing Ad Hoc Networks  

Microsoft Academic Search

Ad hoc networks are a new wireless networking paradigm for mobile hosts. Unlike traditional mobile wireless networks, ad hoc networks do not rely on any fixed infrastructure. Instead, hosts rely on each other to keep the network connected. The military tactical and other security-sensitive operations are still the main applications of ad hoc networks, although there is a trend to

Lidong Zhou; Zygmunt J. Haas

1999-01-01

104

NASA Network  

NASA Technical Reports Server (NTRS)

The NASA Network includes nine NASA operated and partner operated stations covering North America, the west coast of South America, the Pacific, and Western Australia . A new station is presently being setup in South Africa and discussions are underway to add another station in Argentina. NASA SLR operations are supported by Honeywell Technical Solutions, Inc (HTSI), formally AlliedSignal Technical Services, The University of Texas, the University of Hawaii and Universidad Nacional de San Agustin.

Carter, David; Wetzel, Scott

2000-01-01

105

Network Management Extensions, performing network management activities  

Microsoft Academic Search

When developing a network management system, the developer is faced with many choices concerning how to interact with the network resources and how to embed into the schema of manager agent architectures. In this paper we propose NMX (Network Management Extensions), a software framework implementation based on Java JMX (Java Management Extensions) technology and SNMP (Simple Network Management Protocol) combining

Mihnea A. Magheti; Andrei N. Ciobanu; Eduard C. Popovici

2010-01-01

106

Improving network utilization over heterogeneous airborne networks  

Microsoft Academic Search

Existing and future military networks vary widely in bandwidth and other network characteristics, potentially challenging deployment of services and applications across heterogeneous data links. To address this challenge, General Dynamics and Naval Research Laboratory created network services to allow applications to use wireless data links more efficiently. The basis for the network services are hooks into the data links and

Peter H. Griffin; Brent L. Rickenbach; Jason A. Rush

2011-01-01

107

Protecting network coded packets in coalition networks  

Microsoft Academic Search

Network coding was found to be useful for ad hoc wireless multicast in disruptive channel and connectivity conditions. In heterogeneous networks, comprising teams with different technical preparedness, it is possible that only the radios of the most advanced teams have sufficient resources to network encode\\/decode. In this case, an interesting solution is partial (hybrid) network coding - only a fraction

Soon Y. Oh; Mario Gerla

2010-01-01

108

Why Network? Theoretical Perspectives on Networking  

ERIC Educational Resources Information Center

In recent years, networking and collaboration have become increasingly popular in education. However, there is at present a lack of attention to the theoretical basis of networking, which could illuminate when and when not to network and under what conditions networks are likely to be successful. In this paper, we will attempt to sketch the…

Muijs, Daniel; West, Mel; Ainscow, Mel

2010-01-01

109

Poster: Delay Tolerant Networking for Sensor Networks  

Microsoft Academic Search

Sensor network deployments may be far removed from com- munications infrastructure such as the Internet. Yet, to be maximally useful, these networks of sensors must ultimately be connected to data storage and analysis facilities. Provid- ing connectivity for such networks may involve exotic and unusual methods of data transfer. In addition, within such networks, problems of intermittent connectivity due to

Melissa Ho; Kevin Fall

2004-01-01

110

Network Management Framework for Wireless Sensor Networks  

NASA Astrophysics Data System (ADS)

Network Management is the process of managing, monitoring, and controlling the network. Conventional network management was based on wired network which is heavy and unsuitable for resource constrained WSNs. WSNs can have large scale network and it is impossible to manage each node individually. Also, polling mechanism of Simple Network Management Protocol (SNMP) impose heavy management traffic overhead. Since management messages consume resources of WSNs, it can affect the performance of the network. Therefore, it is necessary for WSNs to perform energy efficient network management. In this paper, we will propose network management framework. We will introduce cluster-based network management architecture, and classify the Management Information Base (MIB) according to their characteristics. Then, we will define management messages and message exchange operation for each kind of MIB. The analysis result of the management overhead indicates that the proposed framework can reduce management traffic compared to polling mechanism.

Kim, Jaewoo; Jeon, Hahnearl; Lee, Jaiyong

111

[Networks in cognitive research].  

PubMed

This review paper starts from discussing two models of network research: one starting from general networks, the other starting from the Ego. Ego based researches are characterized starting form the model of Dunbar as presenting networks of different size and intimacy, both in real and virtual networks. Researches into the personality determinants of networks mainly shows the effects of extroversion. The future of network research indicates a trend towards relating personal, conceptual, and neural networks. PMID:22781539

Pléh, Csaba

2012-01-01

112

TELECOM 1 multiservices network  

NASA Astrophysics Data System (ADS)

The main objectives of the TELECOM 1 French domestic satellite project are to set up a business communication network which is to carry a wide range of digital services including data, voice, and pictures between a number of small earth stations located on the subscribers' premises. The parallel development of terrestrial specialized services networks has enabled the fitting of the TELECOM 1 network with high interworking capabilities with these networks. It has also allowed TELECOM 1 to be designed as the basis of the Future Integrated Services Digital Network. The TELECOM 1 network consists of the terrestrial network, the satellite network, and the maintenance network. Various elements which include the terrestrial network; the satellite network, and its modulation, TDMA frame and terminals; the System Management Center; the signalling system; and the demand assignment operation which are involved in the operation of the multiservices network are presented. The TELECOM 1 network evolution until 1990 through the rapid development of the ISDN is discussed.

Lombard, D.; Ramat, P.; Rancy, F.

113

Microstructures and properties of laser-glazed plasma-sprayed ZrO{sub 2}-YO{sub 1.5}/Ni-22Cr-10Al-1Y thermal barrier coatings  

SciTech Connect

Thermal barrier coatings (TBCs) consisting of two layers with various yttria contents (ZrO{sub 2}-YO{sub 1.5}/Ni-22Cr-10Al-1Y) were plasma sprayed, and parts of the various specimens were glazed by using a pulsed CO{sub 2} laser. All the specimens were then subjected to furnace thermal cycling tests at 1,100 C; the effect of laser glazing on the durability and failure mechanism of the TBCs was then evaluated. From these results, two models were developed to show the failure mechanism of as-sprayed and laser-glazed TBCs: model A, which is thermal-stress dominant, and model V, which is oxidation-stress dominant. For top coats containing cubic phase, cubic and monoclinic phases, or tetragonal and a relatively larger amount of monoclinic phases, whose degradation is thermal-stress dominant, laser glazing improved the durability of TBCs by a factor of about 2 to 6. Segmented cracks that occurred during glazing proved beneficial for accommodating thermal stress and raising the tolerance to oxidation, which resulted in a higher durability. Thermal barrier coatings with top coats containing tetragonal phase had the highest durability. Degradation of such TBCs resulted mainly from oxidation of the bond coats. For top coats with a greater amount of monoclinic phase, thermal mismatch stress occurred during cooling and detrimentally affected durability.

Tsai, H.L.; Tsai, P.C. [National Taiwan Inst. of Tech., Taipei (Taiwan, Province of China). Dept. of Mechanical Engineering and Technology

1995-12-01

114

Progress in supervised neural networks  

Microsoft Academic Search

Theoretical results concerning the capabilities and limitations of various neural network models are summarized, and some of their extensions are discussed. The network models considered are divided into two basic categories: static networks and dynamic networks. Unlike static networks, dynamic networks have memory. They fall into three groups: networks with feedforward dynamics, networks with output feedback, and networks with state

D. R. Hush; B. G. Horne

1993-01-01

115

Robustness of a Network of Networks  

NASA Astrophysics Data System (ADS)

Network research has been focused on studying the properties of a single isolated network, which rarely exists. We develop a general analytical framework for studying percolation of n interdependent networks. We illustrate our analytical solutions for three examples: (i) For any tree of n fully dependent Erdos-R'enyi (ER) networks, each of average degree k, we find that the giant component P?=p[1-(-kP?)]^n where 1 - p is the initial fraction of removed nodes. This general result coincides for n = 1 with the known second-order phase transition for a single network. For any n>1 cascading failures occur and the percolation becomes an abrupt first-order transition. (ii) For a starlike network of n partially interdependent ER networks, P? depends also on the topology--in contrast to case (i). (iii) For a looplike network formed by n partially dependent ER networks, P? is independent of n.

Gao, Jianxi; Buldyrev, Sergey V.; Stanley, H. Eugene; Havlin, Shlomo

2012-02-01

116

Directions in active networks  

Microsoft Academic Search

Active networks represent a significant step in the evolution of packet-switched networks, from traditional packet-forwarding engines to more general functionality supporting dynamic control and modification of network behavior. However, the phrase “active network” means different things to different people. This article introduces a model and nomenclature for talking about active networks, describes some possible approaches in terms of that nomenclature,

K. L. Calvert; S. Bhattacharjee; E. Zegura; J. Sterbenz

1998-01-01

117

Network Management Survey.  

National Technical Information Service (NTIS)

The report presents the results of a study of management practices in different computer networks. Five networks were chosen as typical of different approaches to network implementation and management: Defense Advanced Research Projects Agency (ARPA) Netw...

I. W. Cotton

1974-01-01

118

NHLBI ARDS Network  

MedlinePLUS

... Patient and Family Information ARDSNet Studies Related Links Network Sites For Clinicians & Researchers For the General Public ... of the factors considered in the selection of network clinical trials? What is the ARDS Network? Who ...

119

Air Traffic Network Project  

NASA Technical Reports Server (NTRS)

The high level requirement of the Air Traffic Network (ATN) project is to provide a mechanism for evaluating the impact of router scheduling modifications on a networks efficiency, without implementing the modifications in the live network.

1997-01-01

120

Itegrated Network Management.  

National Technical Information Service (NTIS)

Network management includes three independent and closely related subjects -- network monitoring, control and administration. Network monitoring activities can be classified into five groups -- status, configuration, performance, event and fault monitorin...

Z. Ma

1983-01-01

121

Randomized Distributed Network Coding.  

National Technical Information Service (NTIS)

A network and a method for transmitting processes in a network are disclosed, where a randomized coding approach is provided. Network nodes transmit on each outgoing link a linear combination of incoming signals, specified by independently and randomly ch...

D. Karger M. Effros M. Medard R. Koetter T. Ho

2004-01-01

122

Networks in immunology  

NASA Astrophysics Data System (ADS)

In this note we present a minireview of the idiotypic network in immunology and we study a very simple model for this network. We discuss some of the similarities of this model with spin glasses and neural networks.

Parisi, Giorgio

1989-12-01

123

Complex Networks and Graphs  

NSDL National Science Digital Library

Students learn about complex networks and how to represent them using graphs. They also learn that graph theory is a useful mathematical tool for studying complex networks in diverse applications of science and engineering, such as neural networks in the brain, biochemical reaction networks in cells, communication networks, such as the internet, and social networks. Topics covered include set theory, defining a graph, as well as defining the degree of a node and the degree distribution of a graph.

Complex Systems Science Laboratory

124

Correlation in business networks  

NASA Astrophysics Data System (ADS)

This paper considers business networks. Through empirical study, we show that business networks display characteristics of small-world networks and scale-free networks. In this paper, we characterize firms as sales and bankruptcy probabilities. A correlation between sales and a correlation between bankruptcy probabilities in business networks are also considered. The results reveal that the correlation between sales depends strongly on the type of network, whereas the correlation between bankruptcy probabilities does so only weakly.

Souma, Wataru; Aoyama, Hideaki; Fujiwara, Yoshi; Ikeda, Yuichi; Iyetomi, Hiroshi; Kaizoji, Taisei

2006-10-01

125

TVRadio Network  

NSDL National Science Digital Library

This free service offers Webmasters a searchable database of TV and Radio stations that they can place on their site for a 50/50 split on advertising. Visitors can use this resource at partner sites that mirror the database, or simply visit the TVRadio Network homepage. Users can browse the listings by category or location. Each listing includes a link to the homepage and format and speed in which content is offered (RealPlayer or Windows Media Player or both). Selected stations may be added to "My Stations" or emailed to a friend. A keyword search engine is also provided. While a few of the category listings seem a bit sparse -- there are only 22 entries for Jazz, for instance -- the location listings are a very useful resource for those seeking nation-specific audio and video broadcasts.

126

Psychotherapy Networker  

NSDL National Science Digital Library

The Psychotherapy Networker website is the online presence of the print magazine, which covers "the everyday challenges of clinical practice, while also offering perspective on the social issues, critical ideas, and therapeutic innovations shaping the direction of the [psychotherapy] profession." Visitors to the site will find the full text of the "Current Issue" and the full text of "Recent Issues". Subscribers to the bimonthly magazine have full access to the "Archives". On the left side of any page is a "Popular Topics" link that has over a dozen topics, including "The Business of Therapy", "Challenging Cases", "Ethics", and "Trauma". Visitors should check out the "CE Courses" link at the top of any page as it has many types of continuing education course offerings, such as "Telecourses", "Audio Courses" and "Online Courses". There is even a "Magazine Quiz" to take that will yield two CE credits if 12 questions about designated articles are answered correctly.

127

Native Networks  

NSDL National Science Digital Library

Over the past few years, Native Americans have made significant contributions in a host of different media, including television, radio, and film. Involved in all aspects of this type of artistic and cultural expression, many Native Americans have also looked for a way to disseminate their substantial efforts in this arena. Fortunately, there is the Native Networks website (first launched in 2001), designed to provide information about such creations. The website was created by the Film and Video Center of the National Museum of the American Indian, and contains information about upcoming Native American film festivals and âÂÂclose-upâ profiles of people actively working in the field. Some of these features include material on the indigenous video makers in Mexico and an in-depth look at the film âÂÂHouse Made of DawnâÂÂ, which deals with a young Pueblo man in crisis. The site is available in both Spanish and English versions. [KMG

128

Delay Tolerant Networking Architecture for Airborne Networking.  

National Technical Information Service (NTIS)

In this work we present our recent results of the novel Delay Tolerant Networking (DTN)-based probabilistic routing approach to achieve reliable communication in Airborne Networking (AN) environment associated with intermittent connectivity. The challenge...

T. Saadawi

2010-01-01

129

Network Management of Highly Adaptive Communication Networks.  

National Technical Information Service (NTIS)

This report documents networking models, network solutions, programming techniques for parallel processing, and parallelled algorithm comparisons. Several papers are contained in the report. An operational research model and associated mathematics are pre...

J. L. Kennington J. M. Colombi R. V. Helgason

1988-01-01

130

Interconnection networks  

DOEpatents

A network of interconnected processors is formed from a vertex symmetric graph selected from graphs GAMMA/sub d/(k) with degree d, diameter k, and (d + 1)exclamation/ (d /minus/ k + 1)exclamation processors for each d greater than or equal to k and GAMMA/sub d/(k, /minus/1) with degree d /minus/ 1, diameter k + 1, and (d + 1)exclamation/(d /minus/ k + 1)exclamation processors for each d greater than or equal to k greater than or equal to 4. Each processor has an address formed by one of the permutations from a predetermined sequence of letters chosen a selected number of letters at a time, and an extended address formed by appending to the address the remaining ones of the predetermined sequence of letters. A plurality of transmission channels is provided from each of the processors, where each processor has one less channel than the selected number of letters forming the sequence. Where a network GAMMA/sub d/(k, /minus/1) is provided, no processor has a channel connected to form an edge in a direction delta/sub 1/. Each of the channels has an identification number selected from the sequence of letters and connected from a first processor having a first extended address to a second processor having a second address formed from a second extended address defined by moving to the front of the first extended address the letter found in the position within the first extended address defined by the channel identification number. The second address is then formed by selecting the first elements of the second extended address corresponding to the selected number used to form the address permutations. 9 figs.

Faber, V.; Moore, J.W.

1988-06-20

131

The deep space network  

NASA Technical Reports Server (NTRS)

Summaries are given of Deep Space Network progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations.

1975-01-01

132

Network Engineering for Agile Belief Network Models  

Microsoft Academic Search

The construction of a large, complex belief network model, like any major system development effort, requires a structured process to manage system design and development. This paper describes a belief network engineering process based on the spiral system lifecycle model. The problem of specifying numerical probability distributions for random variables in a belief network is best treated not in isolation,

Kathryn Blackmond Laskey; Suzanne M. Mahoney

2000-01-01

133

Green Network Planning of Single Frequency Networks  

Microsoft Academic Search

This paper investigates the network deployment of single frequency networks (SFN) based on OFDM schemes that are standardized for terrestrial broadcasting systems, for digital audio broadcasting (DAB) and for digital video broadcasting (DVB) systems. The concept of green network planning is presented. The term `green' refers to low carbon, energy efficiency and low exposure to radiation, parameters important for the

George Koutitas

2010-01-01

134

Computer Networks and Networking: A Primer.  

ERIC Educational Resources Information Center

Provides a basic introduction to computer networks and networking terminology. Topics addressed include modems; the Internet; TCP/IP (Transmission Control Protocol/Internet Protocol); transmission lines; Internet Protocol numbers; network traffic; Fidonet; file transfer protocol (FTP); TELNET; electronic mail; discussion groups; LISTSERV; USENET;…

Collins, Mauri P.

1993-01-01

135

Data center networks and network architecture  

NASA Astrophysics Data System (ADS)

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).

Esaki, Hiroshi

2014-02-01

136

Network epidemiology and plant trade networks  

PubMed Central

Models of epidemics in complex networks are improving our predictive understanding of infectious disease outbreaks. Nonetheless, applying network theory to plant pathology is still a challenge. This overview summarizes some key developments in network epidemiology that are likely to facilitate its application in the study and management of plant diseases. Recent surveys have provided much-needed datasets on contact patterns and human mobility in social networks, but plant trade networks are still understudied. Human (and plant) mobility levels across the planet are unprecedented—there is thus much potential in the use of network theory by plant health authorities and researchers. Given the directed and hierarchical nature of plant trade networks, there is a need for plant epidemiologists to further develop models based on undirected and homogeneous networks. More realistic plant health scenarios would also be obtained by developing epidemic models in dynamic, rather than static, networks. For plant diseases spread by the horticultural and ornamental trade, there is the challenge of developing spatio-temporal epidemic simulations integrating network data. The use of network theory in plant epidemiology is a promising avenue and could contribute to anticipating and preventing plant health emergencies such as European ash dieback.

Pautasso, Marco; Jeger, Mike J.

2014-01-01

137

Network epidemiology and plant trade networks.  

PubMed

Models of epidemics in complex networks are improving our predictive understanding of infectious disease outbreaks. Nonetheless, applying network theory to plant pathology is still a challenge. This overview summarizes some key developments in network epidemiology that are likely to facilitate its application in the study and management of plant diseases. Recent surveys have provided much-needed datasets on contact patterns and human mobility in social networks, but plant trade networks are still understudied. Human (and plant) mobility levels across the planet are unprecedented-there is thus much potential in the use of network theory by plant health authorities and researchers. Given the directed and hierarchical nature of plant trade networks, there is a need for plant epidemiologists to further develop models based on undirected and homogeneous networks. More realistic plant health scenarios would also be obtained by developing epidemic models in dynamic, rather than static, networks. For plant diseases spread by the horticultural and ornamental trade, there is the challenge of developing spatio-temporal epidemic simulations integrating network data. The use of network theory in plant epidemiology is a promising avenue and could contribute to anticipating and preventing plant health emergencies such as European ash dieback. PMID:24790128

Pautasso, Marco; Jeger, Mike J

2014-01-01

138

Networking the Classroom.  

ERIC Educational Resources Information Center

This issue of "CQ Researcher" examines the theme of computer networking in the classroom and discusses uses past and present. It begins with an essay by Christopher Conte that discusses: "Does computer networking really enhance learning? Are teachers adequately prepared to take advantage of computer networking? Will computer networking promote…

Stencel, Sandra, Ed.; And Others

1995-01-01

139

Designing Secure Library Networks.  

ERIC Educational Resources Information Center

Focuses on designing a library network to maximize security. Discusses UNIX and file servers; connectivity to campus, corporate networks and the Internet; separation of staff from public servers; controlling traffic; the threat of network sniffers; hubs that eliminate eavesdropping; dividing the network into subnets; Switched Ethernet;…

Breeding, Michael

1997-01-01

140

MONET: multiwavelength optical networking  

Microsoft Academic Search

This paper presents an overview of the multiwavelength optical networking (MONET) program and summarizes its vision. The program objective is to advance, demonstrate, and integrate network architecture and economics, advanced multiwavelength technology, and network management and control to achieve high capacity, reconfigurable, high performance, reliable multiwavelength optical networks, with scalability to national scale, for both commercial and specialized government applications.

Richard E. Wagner; Rod C. Alferness; A. A. M. Saleh; Matthew S. Goodman

1996-01-01

141

Network observability: theory  

SciTech Connect

A complete theory of network observability is presented. Starting from a fundamental notion of the observability of a network, a number of basic facts relating to network observability, unobservable states, unobservable branches, observable islands, relevancy of measurements, etc. are derived. Simple and efficient algorithms can be developed based on these basic facts to test network observability, identify observable islands and place measurements for observability.

Monticelli, A.; Wu, F.F.

1985-05-01

142

Electronic Communication Networks.  

ERIC Educational Resources Information Center

Discusses educational uses, types, operation, advantages, popular features, and subscription rates of electronic communication networks. Factors to consider when choosing a network are described, and a table listing networks designed for educators includes information on the network producer, target audience, features, subscription rates, and…

Raimondi, Sharon L.

1984-01-01

143

Troubleshooting wireless mesh networks  

Microsoft Academic Search

Effective network troubleshooting is critical for maintaining effi- cient and reliable network operation. Troubleshooting is especially challenging in multi-hop wireless networks because the behavior of such networks depends on complicated interactions between many factors such as RF noise, signal propagation, node interference, and traffic flows. In this paper we propose a new direction for re- search on fault diagnosis in

Lili Qiu; Paramvir Bahl; Ananth Rao; Lidong Zhou

2006-01-01

144

Network Telescopes: Technical Report  

Microsoft Academic Search

A network telescope is a portion of routed IP address space in which little or no legitimate traffic exists. Monitoring unexpected traffic arriving at a network telescope provides the opportunity to view remote network security events such as various forms of flooding denial-of-service attacks, infection of hosts by Internet worms, and network scanning. In this paper, we examine the effects

David Moore; Colleen Shannon; Geoffrey M. Voelkery; Stefan Savagey

145

Building Air Monitoring Networks  

ERIC Educational Resources Information Center

The different components of air monitoring networks, the status of air monitoring in the United States, and the services and activities of the three major American network builders are detailed. International air monitoring networks and alert systems are identified, with emphasis on the Dutch air monitoring network. (BT)

Environmental Science and Technology, 1977

1977-01-01

146

NAV - Network Analysis Visualization  

Microsoft Academic Search

In this paper we discuss the Network Analysis Visualization (NAV) project, a tool for investigating high level network events. Moni- toring network activity has been a critical task for administrators since networks were first introduced, both for maintaining system security and tracking resource utilization. Traditionally, the tools used by both enterprise and home users display detailed packet in- formation in

Meghan Allen; Peter McLachlan

147

Economics of Networks  

NSDL National Science Digital Library

Nicholas Economides of the Stern Business School at New York University has assembled a "collection of information on economic issues of networks, such as the internet, telephone and fax communications networks, the railroad network, the airline network, and financial exchange and credit card networks." The site contains a large collection of research papers on networks, compatibility, and related issues; and on financial networks and electronic trading written by Economides in collaboration with other researchers. Visitors to the site can choose to read the abstracts online or download papers (in Adobe Acrobat [.pdf] or Postscript format). In addition, there is also an extensive bibliography.

Economides, Nicholas.

1997-01-01

148

Network Observability Transitions  

NASA Astrophysics Data System (ADS)

In the modeling, monitoring, and control of complex networks, a fundamental problem concerns the comprehensive determination of the state of the system from limited measurements. Using power grids as example networks, we show that this problem leads to a new type of percolation transition, here termed a network observability transition, which we solve analytically for the configuration model. We also demonstrate a dual role of the network’s community structure, which both facilitates optimal measurement placement and renders the networks substantially more sensitive to “observability attacks.” Aside from their immediate implications for the development of smart grids, these results provide insights into decentralized biological, social, and technological networks.

Yang, Yang; Wang, Jianhui; Motter, Adilson E.

2012-12-01

149

Resonant guided wave networks.  

PubMed

A resonant guided wave network is an optical materials design consisting of power-splitting elements arranged at the nodes of a waveguide network. The resulting wave dispersion depends on the network layout due to localized resonances at several length scales in the network. These structures exhibit both localized resonances with a Q approximately 80 at 1550 nm wavelength as well as photonic bands and band gaps in large periodic networks at infrared wavelengths. PMID:20481961

Feigenbaum, Eyal; Atwater, Harry A

2010-04-01

150

Valley Networks  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Released 30 July 2003

Valley networks are a relatively common feature in the southern highlands of Mars. This THEMIS visible image contains several of these small channels. Some appear clustered near the smaller crater at the top of the image. There is still some debate over the origin of these enigmatic martian landforms. Were they caused by overland flow after precipitation, underground sapping, or a combination of both?

Image information: VIS instrument. Latitude -40.6, Longitude 165.2 East (194.8 West). 19 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

2003-01-01

151

Percolation of a general network of networks  

NASA Astrophysics Data System (ADS)

Percolation theory is an approach to study the vulnerability of a system. We develop an analytical framework and analyze the percolation properties of a network composed of interdependent networks (NetONet). Typically, percolation of a single network shows that the damage in the network due to a failure is a continuous function of the size of the failure, i.e., the fraction of failed nodes. In sharp contrast, in NetONet, due to the cascading failures, the percolation transition may be discontinuous and even a single node failure may lead to an abrupt collapse of the system. We demonstrate our general framework for a NetONet composed of n classic Erd?s-Rényi (ER) networks, where each network depends on the same number m of other networks, i.e., for a random regular network (RR) formed of interdependent ER networks. The dependency between nodes of different networks is taken as one-to-one correspondence, i.e., a node in one network can depend only on one node in the other network (no-feedback condition). In contrast to a treelike NetONet in which the size of the largest connected cluster (mutual component) depends on n, the loops in the RR NetONet cause the largest connected cluster to depend only on m and the topology of each network but not on n. We also analyzed the extremely vulnerable feedback condition of coupling, where the coupling between nodes of different networks is not one-to-one correspondence. In the case of NetONet formed of ER networks, percolation only exhibits two phases, a second order phase transition and collapse, and no first order percolation transition regime is found in the case of the no-feedback condition. In the case of NetONet composed of RR networks, there exists a first order phase transition when the coupling strength q (fraction of interdependency links) is large and a second order phase transition when q is small. Our insight on the resilience of coupled networks might help in designing robust interdependent systems.

Gao, Jianxi; Buldyrev, Sergey V.; Stanley, H. Eugene; Xu, Xiaoming; Havlin, Shlomo

2013-12-01

152

Percolation of a general network of networks.  

PubMed

Percolation theory is an approach to study the vulnerability of a system. We develop an analytical framework and analyze the percolation properties of a network composed of interdependent networks (NetONet). Typically, percolation of a single network shows that the damage in the network due to a failure is a continuous function of the size of the failure, i.e., the fraction of failed nodes. In sharp contrast, in NetONet, due to the cascading failures, the percolation transition may be discontinuous and even a single node failure may lead to an abrupt collapse of the system. We demonstrate our general framework for a NetONet composed of n classic Erd?s-Rényi (ER) networks, where each network depends on the same number m of other networks, i.e., for a random regular network (RR) formed of interdependent ER networks. The dependency between nodes of different networks is taken as one-to-one correspondence, i.e., a node in one network can depend only on one node in the other network (no-feedback condition). In contrast to a treelike NetONet in which the size of the largest connected cluster (mutual component) depends on n, the loops in the RR NetONet cause the largest connected cluster to depend only on m and the topology of each network but not on n. We also analyzed the extremely vulnerable feedback condition of coupling, where the coupling between nodes of different networks is not one-to-one correspondence. In the case of NetONet formed of ER networks, percolation only exhibits two phases, a second order phase transition and collapse, and no first order percolation transition regime is found in the case of the no-feedback condition. In the case of NetONet composed of RR networks, there exists a first order phase transition when the coupling strength q (fraction of interdependency links) is large and a second order phase transition when q is small. Our insight on the resilience of coupled networks might help in designing robust interdependent systems. PMID:24483520

Gao, Jianxi; Buldyrev, Sergey V; Stanley, H Eugene; Xu, Xiaoming; Havlin, Shlomo

2013-12-01

153

MPLS network tuning: enabling hitless network engineering  

Microsoft Academic Search

MPLS traffic engineering has primarily focused on efficient route setups. However, as data traffic explodes, there is an increased demand for tools that enable network-wide tuning in order to maintain high levels of end-to-end network efficiency. Network tuning aims to pro-actively reconfigure traffic without causing any service disruption. In this paper, we explore the requirements on management systems to support

Swarup Acharya; Bhawna Gupta; Pankaj Risbood; Anurag Srivastava

2003-01-01

154

Como Lo Hago Yo: Lipomas Medulares  

PubMed Central

Basados en la experiencia de 82 casos; en 5% se observaron anomalías pélvicas asociadas. En los menores de 3 años el motivo de consulta (85%) fue la tumoración. En los mayores de 3 años (42%) tenía problemas neurológicos. Solo el 24% preocupados por la tumoración. El objetivo de la cirugía es desanclar la médula y no remover la totalidad del lipoma. El lipoma de filum es el que es mas simple para operar. Aún cuando la escuela francesa propone operar solamente cuando hay síntomas favorezco cirugía preventiva. Favorezco una segunda cirugía si hay signos de anclaje postoperatorio, aún cuando observamos empeoramiento postoperatorio motor en 2.5% de los operados y urológico a largo plazo en 6% de los operados.

Portillo, Santiago

2014-01-01

155

Translated chemical reaction networks.  

PubMed

Many biochemical and industrial applications involve complicated networks of simultaneously occurring chemical reactions. Under the assumption of mass action kinetics, the dynamics of these chemical reaction networks are governed by systems of polynomial ordinary differential equations. The steady states of these mass action systems have been analyzed via a variety of techniques, including stoichiometric network analysis, deficiency theory, and algebraic techniques (e.g., Gröbner bases). In this paper, we present a novel method for characterizing the steady states of mass action systems. Our method explicitly links a network's capacity to permit a particular class of steady states, called toric steady states, to topological properties of a generalized network called a translated chemical reaction network. These networks share their reaction vectors with their source network but are permitted to have different complex stoichiometries and different network topologies. We apply the results to examples drawn from the biochemical literature. PMID:24610094

Johnston, Matthew D

2014-05-01

156

Parallel Consensual Neural Networks  

NASA Technical Reports Server (NTRS)

A new neural network architecture is proposed and applied in classification of remote sensing/geographic data from multiple sources. The new architecture is called the parallel consensual neural network and its relation to hierarchical and ensemble neural networks is discussed. The parallel consensual neural network architecture is based on statistical consensus theory. The input data are transformed several times and the different transformed data are applied as if they were independent inputs and are classified using stage neural networks. Finally, the outputs from the stage networks are then weighted and combined to make a decision. Experimental results based on remote sensing data and geographic data are given. The performance of the consensual neural network architecture is compared to that of a two-layer (one hidden layer) conjugate-gradient backpropagation neural network. The results with the proposed neural network architecture compare favorably in terms of classification accuracy to the backpropagation method.

Benediktsson, J. A.; Sveinsson, J. R.; Ersoy, O. K.; Swain, P. H.

1993-01-01

157

Terminal Attractors In Neural Networks  

NASA Technical Reports Server (NTRS)

Neural networks made to "learn" faster. Report presents theoretical study of terminal attractors in neural networks. Includes systematic analysis of applications to activation dynamics of neural networks.

Zak, Michail A.

1991-01-01

158

Satellite networks for education  

NASA Technical Reports Server (NTRS)

Satellite based educational networking is discussed with particular attention given to the potential uses of communications satellites to help meet educational needs in the United states. Four major subject areas were covered; (1) characteristics and structure of networks, (2) definition of pressures within educational establishment that provide motivation for various types of networks, (3) examination of current educational networking status for educational radio and television, instructional television fixed services, inter- and intra-state educational communication networks, computer networks, and cable television for education, and (4) identification of possible satellite based educational telecommunication services and three alternatives for implementing educational satellite systems.

Singh, J. P.; Morgan, R. P.; Rosenbaum, F. J.

1972-01-01

159

Computer Analysis of Networks Via Inversion of Network Equations.  

National Technical Information Service (NTIS)

The report describes the operation and use of CANINE (Computer Analysis of Networks via Inversion of Network Equations), a time-domain analysis program, for linear time-invariant networks. The networks may contain dependent and independent sources of all ...

P. M. Russo

1968-01-01

160

Neural network control for TCP network congestion  

Microsoft Academic Search

Active queue management (AQM) has been widely used for congestion avoidance in transmission control protocol (TCP) networks. Although numerous AQM schemes have been proposed to regulate a queue size close to a reference level, most of them are incapable of adequately adapting to TCP network dynamics due to TCP's non-linearity and time-varying stochastic properties. To alleviate these problems, we introduce

Hyun C. Cho; M. Sami Fadali; Hyunjeong Lee

2005-01-01

161

Knowledge Network Modeling Based on Complex Networks  

Microsoft Academic Search

As human society entered the era of knowledge economy, lasting in-depth studies have been done to knowledge learning, knowledge management, and other fields. How to identify, acquire, develop, decompose, store, and transmit knowledge has become the focus of research. The creation of knowledge network supplies a better solution to this problem. Knowledge network is composed of knowledge points. Each knowledge

FAN Yan-jing; WANG Hua-yu

2008-01-01

162

Applying Static Network Protocols to Dynamic Networks  

Microsoft Academic Search

This paper addresses the problem of how to adapt an algorithm designed for fixed topology networks to produce the intended results, when run in a network whose topology changes dynamically, in spite of encountering topological changes during its execution. We present a simple and unified procedure, called a reset procedure, which, when combined with the static algorithm, achieves this adaptation.

Yehuda Afek; Baruch Awerbuch; Eli Gafni

1987-01-01

163

The deep space network  

NASA Technical Reports Server (NTRS)

The functions and facilities of the Deep Space Network are considered. Progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations is reported.

1980-01-01

164

Distributed Network Resource Allocation.  

National Technical Information Service (NTIS)

This thesis addresses several resource allocation problems that arise in the context of distributed networks. First, we present a scheme for accessing shared copies of objects in a network that has asymptotically optimal expected cost per access for a cla...

A. W. Richa

1998-01-01

165

The deep space network  

NASA Technical Reports Server (NTRS)

The facilities, programming system, and monitor and control system for the deep space network are described. Ongoing planetary and interplanetary flight projects are reviewed, along with tracking and ground-based navigation, communications, and network and facility engineering.

1977-01-01

166

OncoArray Network  

Cancer.gov

The overall goal of the OncoArray Network is to gain new insight into the genetic architecture and mechanisms underlying breast, ovarian, prostate, colorectal, and lung cancers. The Network's major aim is to discover new cancer susceptibility variants.

167

Class network routing  

DOEpatents

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.

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

2009-09-08

168

Congenital Heart Information Network  

MedlinePLUS

... heart defects. Important Notice The Congenital Heart Information Network website is temporarily out of service. Please join ... and Uwe Baemayr for The Congenital Heart Information Network Exempt organization under Section 501(c)3. Copyright © ...

169

Security of Complex Networks.  

National Technical Information Service (NTIS)

The main goal of the project was to conduct a comprehensive study of complex networks from the perspectives of security and information protection using an interdisciplinary approach. Specific Objectives were: (1) cascading breakdown of complex networks t...

Y. Lai

2010-01-01

170

Routing in Unreliable Networks.  

National Technical Information Service (NTIS)

Consider strategies for selecting message routes in unreliable data communication networks. The following assumptions are made: the nodes of the network are perfectly reliable; the links are unreliable, and for each link l there is a probability P sub l, ...

I. M. Figueredo

1986-01-01

171

Network Nation Revisited  

NSDL National Science Digital Library

The Network Nation Revisited" is an analysis of the predictions made by Hiltz and Turoff in _The Network Nation_, one of the seminal texts (published in 1978) in the field of Computer Mediated Communications.

172

Measuring of network vulnerability  

NASA Astrophysics Data System (ADS)

The application of computer network has mushroomed with the networking manufacture, networking instruments and etc. The ability of the production or system that can endures the breakage and the fault is a very important performance index. Especially today, the problems by reason of information security including hidden failures and defects in the system directly threaten the security and performance of system. This performance index to indicate these cases is the vulnerability. Networks vulnerability is defined as the abilities of network which to endure attacks, destroy and faults, also being called invulnerability of network. Vulnerability is often measured by the degree of vulnerability, which directly indicates the magnitude of invulnerability. This paper firstly introduces the conception of networks vulnerability, and distinct the analysis methods of networks vulnerability. The results of this paper are being looked forward to giving much direction on the system analysis and synthesis too.

Wang, Xianpei; Zhang, Jun; Wang, Quande

2003-09-01

173

Distributed network scheduling  

NASA Technical Reports Server (NTRS)

We investigate missions where communications resources are limited, requiring autonomous planning and execution. Unlike typical networks, spacecraft networks are also suited to automated planning and scheduling because many communications can be planned in advance.

Clement, Bradley J.; Schaffer, Steven R.

2005-01-01

174

Tuned analog network  

NASA Technical Reports Server (NTRS)

A noninverting, direct current amplifier stage is cascaded into an integrator stage to form a two stage tuned network with a single input junction common to both stages. The network provides independent adjustment of center frequency, bandwidth and voltage gain. The insertion of a positive feedback loop between the stages provides a very narrow bandwidth network. The addition of back to back zener diodes between the common input node and ground converts the network into an oscillator.

Kleinberg, L. L. (inventor)

1983-01-01

175

Networked Distributed Source Coding  

Microsoft Academic Search

\\u000a The data sensed by different sensors in a sensor network is typically correlated. A natural question is whether the data correlation\\u000a can be exploited in innovative ways along with network information transfer techniques to design efficient and distributed\\u000a schemes for the operation of such networks. This necessarily involves a coupling between the issues of compression and networked\\u000a data transmission that

Shizheng Li; Aditya Ramamoorthy

176

On the advantage of network coding for improving network throughput  

Microsoft Academic Search

Given a data network with link capacities, we consider the throughput of the network for a multicast session involving a source node and a given set of terminals. It is known that network coding can improve the throughput of the network. We study the coding advantage, i.e. the ratio of the throughput using network coding to that without using network

Amit Agarwal; Moses Charikar

2004-01-01

177

The Handoff Study on Satellite Networks Based on Mobility Network  

Microsoft Academic Search

In order to provide the Internet access for the users in large mobile networks and achieve the IP routing in the satellite constellation network, a new design method based on mobile network is put forward for LEO satellite constellation networks which realizes the IP route selection function and reduces the dependence of satellite constellation communication network to the ground network.

Donghai Shi; Chaojing Tang

2006-01-01

178

Ambient networks: a framework for mobile network cooperation  

Microsoft Academic Search

Ambient Networks represents a new networking approach that aims at enabling the cooperation of heterogeneous networks and networking resources, on demand and transparently. This should happen without the need for pre-configuration or offline negotiation between network operators. Ambient Networks clearly separates the control space from the transport protocol, and introduces a common control space called the Ambient Control Space that

Norbert Niebert; Ericsson Allee

2005-01-01

179

Issues in gigabit networking  

Microsoft Academic Search

The focus is on achieving gigabit\\/second rates between network endpoints, based on the use of emerging near-term technology. The topics covered are network multiplexing, striping, congestion control, internetworking, host protocols and interfacing, and the networking of applications at gigabit speeds. These areas are being addressed by researchers in five gigabit testbeds, a collaborative effort involving universities, national laboratories, industry, and

Richard Binder

1992-01-01

180

Temporal-Difference Networks  

Microsoft Academic Search

We introduce a generalization of temporal-difference (TD) learning to networks of interrelated predictions. Rather than relating a single pre- diction to itself at a later time, as in conventional TD methods, a TD network relates each prediction in a set of predictions to other predic- tions in the set at a later time. TD networks can represent and apply TD

Richard S. Sutton; Brian Tanner

2004-01-01

181

Learning Dynamic Bayesian Networks  

Microsoft Academic Search

. Bayesian networks are directed acyclic graphs that represent dependencies between variables in a probabilistic model. Many time series models, including the hidden Markov models (HMMs) used in speech recognition and Kalman filter models used in filtering and control applications, can be viewed as examples of dynamic Bayesian networks. We first provide a brief tutorial on learning and Bayesian networks.

Zoubin Ghahramani

1997-01-01

182

Money with Bank Networks  

Microsoft Academic Search

We allow banks to choose between two networks in a simple version of the Cavalcanti and Wallace (1999) model of inside money. Members of a network have access to credit but must redeem banknotes issued by other members in random meetings. We find equilibria in which members of a particular network issue more valuable notes, but face the same ex-ante

Ricardo de Oliveira Cavalcanti; Henrique Dezemone Forno

2004-01-01

183

Physical Layer Network Coding  

Microsoft Academic Search

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.,

Zhang Shengli; Soung-Chang Liew; Patrick P. K. Lam

2007-01-01

184

Multimedia Networks: Mission Impossible?  

ERIC Educational Resources Information Center

Running multimedia on a network, often difficult because of the memory and processing power required, is becoming easier thanks to new protocols and products. Those developing network design criteria may wish to consider making use of Fast Ethernet, Asynchronous Transfer Method (ATM), switches, "fat pipes", additional network segmentation, and…

Weiss, Andrew M.

1996-01-01

185

Serverless network file systems  

Microsoft Academic Search

We propose a new paradigm for network file system design: serverless network file systems. While traditional network file systems rely on a central server machine, a serverless system utilizes workstations cooperating as peers to provide all file system services. Any machine in the system can store, cache, or control any block of data. Our approach uses this location independence, in

Thomas E. Anderson; Michael D. Dahlin; Jeanna M. Neefe; David A. Patterson; Drew S. Roselli; Randolph Y. Wang

1996-01-01

186

Serverless Network File Systems  

Microsoft Academic Search

In this paper, we propose a new paradigm for network file system design, serverless network file systems. While traditional network file systems rely on a central server machine, a serverless system utilizes workstations cooperating as peers to provide all file system services. Any machine in the system can store, cache, or control any block of data. Our approach uses this

Thomas E. Anderson; Michael Dahlin; Jeanna M. Neefe; David A. Patterson; Drew S. Roselli; Randolph Y. Wang

1995-01-01

187

Modeling wireless shadow networks  

Microsoft Academic Search

In case of natural disasters or intentional attacks, telecommunication networks often get heavily damaged and current resilience schemes have proven to be insufficient for rapid recovery of telecommunication services from catastrophic failures. We consider wireless recovery networks as a strong candidate to provide emergency communication resources in case of such severe network outages, and to preserve, with minimal degradation in

Filip De Turck; Aurel A. Lazar

2004-01-01

188

Drawing Rooted Phylogenetic Networks  

Microsoft Academic Search

The evolutionary history of a collection of species is usually represented by a phylogenetic tree. Sometimes, phylogenetic networks are used as a means of representing reticulate evolution or of showing uncertainty and incompatibilities in evolutionary datasets. This is often done using unrooted phylogenetic networks such as split networks, due in part, to the availability of software (SplitsTree) for their computation

Daniel H. Huson

2009-01-01

189

Detecting Attacks on Networks  

Microsoft Academic Search

As Internet based and intranet based network systems have evolved, they have become invaluable tools that businesses can use to share information and conduct business with online partners. However, hackers have also learned to use these systems to access private networks and their resources. Studies have shown that many organizations have suffered external and internal network intrusions. Internet systems are

Chris Herringshaw

1997-01-01

190

Network information flow  

Microsoft Academic Search

We introduce a new class of problems called network information flow which is inspired by computer network applica- tions. Consider a point-to-point communication network on which a number of information sources are to be mulitcast to certain sets of destinations. We assume that the information sources are mu- tually independent. The problem is to characterize the admissible coding rate region.

Rudolf Ahlswede; Ning Cai; Shuo-yen Robert Li; Raymond W. Yeung

2000-01-01

191

Neural Network Ensembles  

Microsoft Academic Search

Several means for improving the performance and training of neural networks for classification are proposed. Crossvalidation is used as a tool for optimizing network parameters and architecture. It is shown that the remaining residual generalization error can be reduced by invoking ensembles of similar networks

Lars Kai Hansen; Peter Salamon

1990-01-01

192

Survey of Computer Networks.  

National Technical Information Service (NTIS)

The paper presents the results of a survey of state-of-the-art computer networks. It identifies ten major networks: ARPA, COINS, CYBERNET, the Distributed Computer Systems, DLS, MERIT, Network/440, Octopus, TSS, and TUCC and outlines their capabilities an...

J. J. Peterson S. A. Veit

1971-01-01

193

Complexity of network synchronization  

Microsoft Academic Search

The problem of simulating a synchronous network by an asynchronous network is investigated. A new simulation technique, referred to as a synchronizer, which is a new, simple methodology for designing efficient distributed algorithms in asynchronous networks, is proposed. The synchronizer exhibits a trade-off between its communication and time complexities, which is proved to be within a constant factor of the

Baruch Awerbuch

1985-01-01

194

Local access optical networks  

Microsoft Academic Search

Both broadcast CATV and switched telephony access networks have evolved, over decades, to deliver their respective services efficiently. But these networks are not necessarily optimal for services that are rapidly emerging. This suggests that the access infrastructure will likely change in the future, driven by demands for new services and the costs of providing them. Will fiber optic networks play

Nicholas J. Frigo

1996-01-01

195

Appalachia Community Cancer Network  

Cancer.gov

A multidisciplinary team of collaborators from academic institutions and communities in Appalachian regions of Kentucky, West Virginia, Ohio, Pennsylvania, New York, Maryland, and Virginia are proposing to build on a strong foundation of previous activity of the Appalachia Cancer Network (ACN), an NCI-funded Special Populations Network, and develop the Appalachia Community Cancer Network (ACCN).

196

Raptor network video coding  

Microsoft Academic Search

In this paper, we consider the problem of streaming video information on lossy packet networks with path and source diversity, such as wireless mesh networks or more generally overlay architectures. We propose to distribute the video information between several streaming servers and to implement network coding in the forwarding peers in order to increase the quality of the video decoded

Nikolaos Thomos; Pascal Frossard

2007-01-01

197

Telecommunications network management laboratory  

Microsoft Academic Search

This work discusses network management laboratory design and implementation at the University of Wollongong in the School of Electrical, Computer and Telecommunications Engineering in years of 2002 and 2003 for a final year specialisation subject called telecommunication network management for telecommunications engineering students. The design and implementation included that of a network management GUI incorporating the fundamental aspects and functionality

I. Raad; P. Vial

2004-01-01

198

Mapping the Gnutella Network  

Microsoft Academic Search

We studied the topology and protocols of the public Gnutella network. Its substantial user base and open architecture make it a good large-scale, if uncontrolled, testbed. We captured the network's topology, generated traffic, and dynamic behavior to determine its connectivity structure and how well (if at all) Gnutella's overlay network topology maps to the physical Internet infrastructure. Our analysis of

Matei Ripeanu; Adriana Iamnitchi; Ian T. Foster

2002-01-01

199

Networking the Developing World.  

ERIC Educational Resources Information Center

Includes four articles that focus on networking in developing nations: "The Reconfiguration of International Information Infrastructure Assistance Since 1991"; "International Assistance for Networking in Less-Developed Countries: The IDRC Example"; "International Assistance for Internet Growth in Sub-Saharan Africa"; and "Networking in the…

Richards, Pamela Spence; Whalen, Marjorie; White, Wendy D.; Menou, Michel

1998-01-01

200

Security for Sensor Networks  

Microsoft Academic Search

Sensor networks have been identified as being useful in a variety of domains to include the battlefield and perimeter defense. We motivate the security problems that sensor networks face by developing a scenario rep- resentative of a large application class where these networks would be used in the future. We identify threats to this application class and propose a new

Jeffery Undercoffer; Sasikanth Avancha; Anupam Joshi; John Pinkston

2002-01-01

201

Networks: 4.0  

NSDL National Science Digital Library

These five activities give students practice in interpreting and creating network representations that organize information and relate connectedness and other metrics such as time and distance. Among the types of networks studied are transport distances, family trees, events tree diagrams, and factor networks. Teaching suggestions, links to materials, and progress indicators are included.

2010-07-29

202

Packet transport network in metro  

NASA Astrophysics Data System (ADS)

IP packet based services such as high speed internet, IP voice and IP video will be widely deployed in telecom network, which make transport network evolution to packet transport network. Characteristics of transport network and requirements of packet transport network are analyzed, T-MPLS/MPLS-TP based PTN technology is given and it will be used in metro (access, aggregation and core) network.

Huang, Feng; Yi, Xiaobo; Zhang, Hanzheng; Gong, Ping

2008-11-01

203

Network Analysis and Political Science  

Microsoft Academic Search

Political science is fascinated with networks. This fascination builds on networks' descriptive appeal, and descriptions of networks play a prominent role in recent forays into network analysis. For some time, quantitative research has included node-level measures of network characteristics in standard regression models, thereby incorporating network concepts into familiar models. This approach represents an early advance for the literature but

Michael D. Ward; Katherine Stovel; Audrey Sacks

2011-01-01

204

Network Analysis and Political Science  

Microsoft Academic Search

Political science is fascinated with networks. This fascination builds on networks' descriptive appeal, and descriptions of networks play a prominent role in recent forays into network analysis. For some time, quantitative research has included node-level measures of network characteristics in standard regression models, thereby incorporating network concepts into familiar models. This approach represents an early advance for the literature but

Michael D. Ward; Katherine Stovel; Audrey Sacks

205

Network Characterization Service (NCS)  

SciTech Connect

Distributed applications require information to effectively utilize the network. Some of the information they require is the current and maximum bandwidth, current and minimum latency, bottlenecks, burst frequency, and congestion extent. This type of information allows applications to determine parameters like optimal TCP buffer size. In this paper, we present a cooperative information-gathering tool called the network characterization service (NCS). NCS runs in user space and is used to acquire network information. Its protocol is designed for scalable and distributed deployment, similar to DNS. Its algorithms provide efficient, speedy and accurate detection of bottlenecks, especially dynamic bottlenecks. On current and future networks, dynamic bottlenecks do and will affect network performance dramatically.

Jin, Guojun; Yang, George; Crowley, Brian; Agarwal, Deborah

2001-06-06

206

Networks Technology Conference  

NASA Technical Reports Server (NTRS)

The papers included in these proceedings represent the most interesting and current topics being pursued by personnel at GSFC's Networks Division and supporting contractors involved in Space, Ground, and Deep Space Network (DSN) technical work. Although 29 papers are represented in the proceedings, only 12 were presented at the conference because of space and time limitations. The proceedings are organized according to five principal technical areas of interest to the Networks Division: Project Management; Network Operations; Network Control, Scheduling, and Monitoring; Modeling and Simulation; and Telecommunications Engineering.

Tasaki, Keiji K. (editor)

1993-01-01

207

NASA's unique networking environment  

NASA Technical Reports Server (NTRS)

Networking is an infrastructure technology; it is a tool for NASA to support its space and aeronautics missions. Some of NASA's networking problems are shared by the commercial and/or military communities, and can be solved by working with these communities. However, some of NASA's networking problems are unique and will not be addressed by these other communities. Individual characteristics of NASA's space-mission networking enviroment are examined, the combination of all these characteristics that distinguish NASA's networking systems from either commercial or military systems is explained, and some research areas that are important for NASA to pursue are outlined.

Johnson, Marjory J.

1988-01-01

208

Networks and epidemic models  

PubMed Central

Networks and the epidemiology of directly transmitted infectious diseases are fundamentally linked. The foundations of epidemiology and early epidemiological models were based on population wide random-mixing, but in practice each individual has a finite set of contacts to whom they can pass infection; the ensemble of all such contacts forms a ‘mixing network’. Knowledge of the structure of the network allows models to compute the epidemic dynamics at the population scale from the individual-level behaviour of infections. Therefore, characteristics of mixing networks—and how these deviate from the random-mixing norm—have become important applied concerns that may enhance the understanding and prediction of epidemic patterns and intervention measures. Here, we review the basis of epidemiological theory (based on random-mixing models) and network theory (based on work from the social sciences and graph theory). We then describe a variety of methods that allow the mixing network, or an approximation to the network, to be ascertained. It is often the case that time and resources limit our ability to accurately find all connections within a network, and hence a generic understanding of the relationship between network structure and disease dynamics is needed. Therefore, we review some of the variety of idealized network types and approximation techniques that have been utilized to elucidate this link. Finally, we look to the future to suggest how the two fields of network theory and epidemiological modelling can deliver an improved understanding of disease dynamics and better public health through effective disease control.

Keeling, Matt J; Eames, Ken T.D

2005-01-01

209

Cheaters in mutualism networks  

PubMed Central

Mutualism-network studies assume that all interacting species are mutualistic partners and consider that all links are of one kind. However, the influence of different types of links, such as cheating links, on network organization remains unexplored. We studied two flower-visitation networks (Malpighiaceae and Bignoniaceae and their flower visitors), and divide the types of link into cheaters (i.e. robbers and thieves of flower rewards) and effective pollinators. We investigated if there were topological differences among networks with and without cheaters, especially with respect to nestedness and modularity. The Malpighiaceae network was nested, but not modular, and it was dominated by pollinators and had much fewer cheater species than Bignoniaceae network (28% versus 75%). The Bignoniaceae network was mainly a plant–cheater network, being modular because of the presence of pollen robbers and showing no nestedness. In the Malpighiaceae network, removal of cheaters had no major consequences for topology. In contrast, removal of cheaters broke down the modularity of the Bignoniaceae network. As cheaters are ubiquitous in all mutualisms, the results presented here show that they have a strong impact upon network topology.

Genini, Julieta; Morellato, L. Patricia C.; Guimaraes, Paulo R.; Olesen, Jens M.

2010-01-01

210

Network topology analysis.  

SciTech Connect

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.

Kalb, Jeffrey L.; Lee, David S.

2008-01-01

211

Layered Random Inference Networks  

NASA Astrophysics Data System (ADS)

Random Boolean Networks (RBN) have been used for decades to study the generic properties of genetic regulatory networks. This paper describes Random Inference Networks (RIN) where the aim is to study the generic properties of inference networks used in high-level information fusion. Previous work has discussed RIN with a linear topology, and this paper introduces RIN with a layered topology. RIN are related to RBN, and exhibit stable, critical and chaotic dynamical regimes. As with RBN, RIN have greatest information propagation in the critical regime. This raises the question as to whether there is a driver for real inference networks to be in the critical regime as has been postulated for genetic regulatory networks. Key Words: situation assessment, inference network, information propagation, criticality

Lingard, David M.

212

Privacy for Mobile Networks via Network Virtualization.  

National Technical Information Service (NTIS)

Today mobile devices have become powerful and ubiquitous. The conveniences afforded by these devices do not come without a cost, however. The use of mobile devices and mobile networks poses a significant risk to privacy. Four privacy requirements for mobi...

T. P. Glidden

2009-01-01

213

Network Analysis Applied to a Bibliographic Network  

Microsoft Academic Search

In this paper we study the ILPnet2 co-authorship network. The ILPnet2 on-line library (www.cs.bris.ac.uk\\/ILPnet2\\/Tools\\/Reports\\/) is a repository of more than 1,000 ILP-related articles by well over 500 authors, published between 1970 and 2003. Co-authorship networks constitute a specific view on bibliographic data, in which scientific publications are modeled as vertices, and two vertices are connected by an undirected edge whenever

Qingyi Gao

2010-01-01

214

Collaborative learning in networks  

PubMed Central

Complex problems in science, business, and engineering typically require some tradeoff between exploitation of known solutions and exploration for novel ones, where, in many cases, information about known solutions can also disseminate among individual problem solvers through formal or informal networks. Prior research on complex problem solving by collectives has found the counterintuitive result that inefficient networks, meaning networks that disseminate information relatively slowly, can perform better than efficient networks for problems that require extended exploration. In this paper, we report on a series of 256 Web-based experiments in which groups of 16 individuals collectively solved a complex problem and shared information through different communication networks. As expected, we found that collective exploration improved average success over independent exploration because good solutions could diffuse through the network. In contrast to prior work, however, we found that efficient networks outperformed inefficient networks, even in a problem space with qualitative properties thought to favor inefficient networks. We explain this result in terms of individual-level explore-exploit decisions, which we find were influenced by the network structure as well as by strategic considerations and the relative payoff between maxima. We conclude by discussing implications for real-world problem solving and possible extensions.

Mason, Winter; Watts, Duncan J.

2012-01-01

215

Epidemics on Interacting Networks  

NASA Astrophysics Data System (ADS)

Epidemic spreading is of great importance in public health, as well as in related fields such as infrastructure. While complex network models have been used with great success to analyze epidemic behavior on single networks, the reality is that our world is made up of a system of interacting networks that do not necessarily share common characteristics. I introduce a model for constructing interacting networks and show that the phase transtion depends on the parameters ?T, kappaA and ?B, where ?T= / over the nodes in both networks, including internetwork links, and ?A and ?B are over the networks considered individually, with no internetwork links. For strongly interacting networks (?T> ?Aand ?B), there exists only one phase transition, between a disease-free phase and an epidemic phase across both networks. For weakly interacting networks (?T< ?A or ?B), a third, ``mixed,'' phase exists, where the disease enters an epidemic on one network alone. The analytic predictions are confirmed by Monte-Carlo simulations.

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

2012-02-01

216

Serial Network Flow Monitor  

NASA Technical Reports Server (NTRS)

Using a commercial software CD and minimal up-mass, SNFM monitors the Payload local area network (LAN) to analyze and troubleshoot LAN data traffic. Validating LAN traffic models may allow for faster and more reliable computer networks to sustain systems and science on future space missions. Research Summary: This experiment studies the function of the computer network onboard the ISS. On-orbit packet statistics are captured and used to validate ground based medium rate data link models and enhance the way that the local area network (LAN) is monitored. This information will allow monitoring and improvement in the data transfer capabilities of on-orbit computer networks. The Serial Network Flow Monitor (SNFM) experiment attempts to characterize the network equivalent of traffic jams on board ISS. The SNFM team is able to specifically target historical problem areas including the SAMS (Space Acceleration Measurement System) communication issues, data transmissions from the ISS to the ground teams, and multiple users on the network at the same time. By looking at how various users interact with each other on the network, conflicts can be identified and work can begin on solutions. SNFM is comprised of a commercial off the shelf software package that monitors packet traffic through the payload Ethernet LANs (local area networks) on board ISS.

Robinson, Julie A.; Tate-Brown, Judy M.

2009-01-01

217

Modelling computer networks  

NASA Astrophysics Data System (ADS)

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.

Max, G.

2011-01-01

218

A network security monitor  

SciTech Connect

The study of security in computer networks is a rapidly growing area of interest because of the proliferation of networks and the paucity of security measures in most current networks. Since most networks consist of a collection of inter-connected local area networks (LANs), this paper concentrates on the security-related issues in a single broadcast LAN such as Ethernet. Specifically, we formalize various possible network attacks and outline methods of detecting them. Our basic strategy is to develop profiles of usage of network resources and then compare current usage patterns with the historical profile to determine possible security violations. Thus, our work is similar to the host-based intrusion-detection systems such as SRI's IDES. Different from such systems, however, is our use of a hierarchical model to refine the focus of the intrusion-detection mechanism. We also report on the development of our experimental LAN monitor currently under implementation. Several network attacks have been simulated and results on how the monitor has been able to detect these attacks are also analyzed. Initial results demonstrate that many network attacks are detectable with our monitor, although it can surely be defeated. Current work is focusing on the integration of network monitoring with host-based techniques. 20 refs., 2 figs.

Heberlein, L.T.; Dias, G.V.; Levitt, K.N.; Mukherjee, B.; Wood, J.; Wolber, D. (California Univ., Davis, CA (USA). Dept. of Electrical Engineering and Computer Science)

1989-11-01

219

Weighted Multiplex Networks  

PubMed Central

One of the most important challenges in network science is to quantify the information encoded in complex network structures. Disentangling randomness from organizational principles is even more demanding when networks have a multiplex nature. Multiplex networks are multilayer systems of nodes that can be linked in multiple interacting and co-evolving layers. In these networks, relevant information might not be captured if the single layers were analyzed separately. Here we demonstrate that such partial analysis of layers fails to capture significant correlations between weights and topology of complex multiplex networks. To this end, we study two weighted multiplex co-authorship and citation networks involving the authors included in the American Physical Society. We show that in these networks weights are strongly correlated with multiplex structure, and provide empirical evidence in favor of the advantage of studying weighted measures of multiplex networks, such as multistrength and the inverse multiparticipation ratio. Finally, we introduce a theoretical framework based on the entropy of multiplex ensembles to quantify the information stored in multiplex networks that would remain undetected if the single layers were analyzed in isolation.

Menichetti, Giulia; Remondini, Daniel; Panzarasa, Pietro; Mondragon, Raul J.; Bianconi, Ginestra

2014-01-01

220

In-Network Monitoring  

NASA Astrophysics Data System (ADS)

Monitoring, i.e., the process of acquiring state information from a network or networked system, is fundamental to system operation. In traditional network and systems management, monitoring is performed on a per-device basis, whereby a centralized management entity polls the devices in its domain for information, which is then analyzed and acted upon. In this chapter, we describe several monitoring algorithms that utilize a new monitoring paradigm called In-network Monitoring. This paradigm is designed to address the above shortcomings, and we demonstrate how it can be applied to managing highly dynamic networked systems. The main idea of In-network Monitoring is to introduce a small management entity inside each network device, which, in addition to monitoring local parameters, can also perform limited management functions and communicate with peering entities in its proximity. The collection of these entities creates a monitoring layer inside the network, which can perform monitoring and control tasks without involving the centralized entity. We demonstrate how In-network monitoring can help building better and more efficient systems. We start with a general description of network monitoring techniques, and then describe two specific cases in which this paradigm generates provably efficient solutions. The first one is in the area of traffic engineering, where there is a need to monitor the aggregated delay of packets along a given network path. The second case deals with the problem of monitoring general aggregated values over the network, with emphasis on computing the values in a distributed way inside the monitoring layer. All together, we believe that this new paradigm presents a promising direction to address the challenges of cost-effective management of future networked systems.

Raz, Danny; Stadler, Rolf; Elster, Constantine; Dam, Mads

221

Defining All-Optical Networks  

NSF Publications Database

Title : LCIS9401 DEFINING ALL-OPTICAL NETWORKS Type : Letter NSF Org: CISE Date : September 1, 1994 File : lcis9401 CHAPTER 1: DEFINING ALL-OPTICAL NETWORKS As the name suggests, All-Optical Networks (AONs) form a class of networks where opti- cal technology (rather than electronics) plays the major role in network functionality. B.4 Local, Metropolitan and Wide Area Optical Communication Networks Communication networks are categorized in terms of their geographical span into local, ...

222

Clustering signatures classify directed networks  

NASA Astrophysics Data System (ADS)

We use a clustering signature, based on a recently introduced generalization of the clustering coefficient to directed networks, to analyze 16 directed real-world networks of five different types: social networks, genetic transcription networks, word adjacency networks, food webs, and electric circuits. We show that these five classes of networks are cleanly separated in the space of clustering signatures due to the statistical properties of their local neighborhoods, demonstrating the usefulness of clustering signatures as a classifier of directed networks.

Ahnert, S. E.; Fink, T. M. A.

2008-09-01

223

Green networks: Energy efficient design for optical networks  

Microsoft Academic Search

In this paper we discuss new energy efficient paradigms for optical networks. With the increasing number of high bandwidth applications, devices used in backbone networks such as optical networks increase. Energy consumption of optical networks is an important issue that has to be addressed. In this work we propose novel routing algorithms for decreasing the energy consumption of optical networks.

Balagangadhar G. Bathula; Jaafar M. H. Elmirghani

2009-01-01

224

Why social networks are different from other types of networks  

Microsoft Academic Search

We argue that social networks differ from most other types of networks, including technological and biological networks, in two important ways. First, they have nontrivial clustering or network transitivity and second, they show positive correlations, also called assortative mixing, between the degrees of adjacent vertices. Social networks are often divided into groups or communities, and it has recently been suggested

M. E. Newman

2003-01-01

225

Network Motifs: Simple Building Blocks of Complex Networks  

Microsoft Academic Search

Complex networks are studied across many fields of science. To uncover their structural design principles, we defined ``network motifs,'' patterns of interconnections occurring in complex networks at numbers that are significantly higher than those in randomized networks. We found such motifs in networks from biochemistry, neurobiology, ecology, and engineering. The motifs shared by ecological food webs were distinct from the

R. Milo; S. Shen-Orr; S. Itzkovitz; N. Kashtan; D. Chklovskii; U. Alon

2002-01-01

226

Reconfigureable network node  

DOEpatents

Nodes in a network having a plurality of nodes establish communication links with other nodes using available transmission media, as the ability to establish such links becomes available and desirable. The nodes predict when existing communications links will fail, become overloaded or otherwise degrade network effectiveness and act to establish substitute or additional links before the node's ability to communicate with the other nodes on the network is adversely affected. A node stores network topology information and programmed link establishment rules and criteria. The node evaluates characteristics that predict existing links with other nodes becoming unavailable or degraded. The node then determines whether it can form a communication link with a substitute node, in order to maintain connectivity with the network. When changing its communication links, a node broadcasts that information to the network. Other nodes update their stored topology information and consider the updated topology when establishing new communications links for themselves.

Vanderveen, Keith B. (Tracy, CA) [Tracy, CA; Talbot, Edward B. (Livermore, CA) [Livermore, CA; Mayer, Laurence E. (Davis, CA) [Davis, CA

2008-04-08

227

Rewiring networks for synchronization.  

PubMed

We study the synchronization of identical oscillators diffusively coupled through a network and examine how adding, removing, and moving single edges affects the ability of the network to synchronize. We present algorithms which use methods based on node degrees and based on spectral properties of the network Laplacian for choosing edges that most impact synchronization. We show that rewiring based on the network Laplacian eigenvectors is more effective at enabling synchronization than methods based on node degree for many standard network models. We find an algebraic relationship between the eigenstructure before and after adding an edge and describe an efficient algorithm for computing Laplacian eigenvalues and eigenvectors that uses the network or its complement depending on which is more sparse. PMID:19045479

Hagberg, Aric; Schult, Daniel A

2008-09-01

228

Visualizing Social Networks  

NASA Astrophysics Data System (ADS)

With today‘s ubiquity and popularity of social network applications, the ability to analyze and understand large networks in an efficient manner becomes critically important. However, as networks become larger and more complex, reasoning about social dynamics via simple statistics is not a feasible option. To overcome these limitations, we can rely on visual metaphors. Visualization nowadays is no longer a passive process that produces images from a set of numbers. Recent years have witnessed a convergence of social network analytics and visualization, coupled with interaction, that is changing the way analysts understand and characterize social networks. In this chapter, we discuss the main goal of visualization and how different metaphors are aimed towards elucidating different aspects of social networks, such as structure and semantics. We also describe a number of methods where analytics and visualization are interwoven towards providing a better comprehension of social structure and dynamics.

Correa, Carlos D.; Ma, Kwan-Liu

229

Expert networks in CLIPS  

NASA Technical Reports Server (NTRS)

Rule-based expert systems may be structurally and functionally mapped onto a special class of neural networks called expert networks. This mapping lends itself to adaptation of connectionist learning strategies for the expert networks. A parsing algorithm to translate C Language Integrated Production System (CLIPS) rules into a network of interconnected assertion and operation nodes has been developed. The translation of CLIPS rules to an expert network and back again is illustrated. Measures of uncertainty similar to those rules in MYCIN-like systems are introduced into the CLIPS system and techniques for combining and hiring nodes in the network based on rule-firing with these certainty factors in the expert system are presented. Several learning algorithms are under study which automate the process of attaching certainty factors to rules.

Hruska, S. I.; Dalke, A.; Ferguson, J. J.; Lacher, R. C.

1991-01-01

230

MSAT network architecture  

NASA Technical Reports Server (NTRS)

The Mobile Satellite (MSAT) communications system will support mobile voice and data services using circuit switched and packet switched facilities with interconnection to the public switched telephone network and private networks. Control of the satellite network will reside in a Network Control System (NCS) which is being designed to be extremely flexible to provide for the operation of the system initially with one multi-beam satellite, but with capability to add additional satellites which may have other beam configurations. The architecture of the NCS is described. The signalling system must be capable of supporting the protocols for the assignment of circuits for mobile public telephone and private network calls as well as identifying packet data networks. The structure of a straw-man signalling system is discussed.

Davies, N. G.; Skerry, B.

1990-01-01

231

NASA Communications Augmentation network  

NASA Technical Reports Server (NTRS)

The NASA Communications (Nascom) Division of the Mission Operations and Data Systems Directorate (MO&DSD) is to undertake a major initiative to develop the Nascom Augmentation (NAUG) network to achieve its long-range service objectives for operational data transport to support the Space Station Freedom Program, the Earth Observing System (EOS), and other projects. The NAUG is the Nascom ground communications network being developed to accommodate the operational traffic of the mid-1990s and beyond. The NAUG network development will be based on the Open Systems Interconnection Reference Model (OSI-RM). This paper describes the NAUG network architecture, subsystems, topology, and services; addresses issues of internetworking the Nascom network with other elements of the Space Station Information System (SSIS); discusses the operations environment. This paper also notes the areas of related research and presents the current conception of how the network will provide broadband services in 1998.

Omidyar, Guy C.; Butler, Thomas E.; Laios, Straton C.

1990-01-01

232

Distributed network scheduling  

NASA Technical Reports Server (NTRS)

Distributed Network Scheduling is the scheduling of future communications of a network by nodes in the network. This report details software for doing this onboard spacecraft in a remote network. While prior work on distributed scheduling has been applied to remote spacecraft networks, the software reported here focuses on modeling communication activities in greater detail and including quality of service constraints. Our main results are based on a Mars network of spacecraft and include identifying a maximum opportunity of improving traverse exploration rate a factor of three; a simulation showing reduction in one-way delivery times from a rover to Earth from as much as 5 to 1.5 hours; simulated response to unexpected events averaging under an hour onboard; and ground schedule generation ranging from seconds to 50 minutes for 15 to 100 communication goals.

Clement, Bradley J.; Schaffer, Steven R.

2004-01-01

233

NASA Integrated Network COOP  

NASA Technical Reports Server (NTRS)

Natural disasters, terrorist attacks, civil unrest, and other events have the potential of disrupting mission-essential operations in any space communications network. NASA's Space Communications and Navigation office (SCaN) is in the process of studying options for integrating the three existing NASA network elements, the Deep Space Network, the Near Earth Network, and the Space Network, into a single integrated network with common services and interfaces. The need to maintain Continuity of Operations (COOP) after a disastrous event has a direct impact on the future network design and operations concepts. The SCaN Integrated Network will provide support to a variety of user missions. The missions have diverse requirements and include anything from earth based platforms to planetary missions and rovers. It is presumed that an integrated network, with common interfaces and processes, provides an inherent advantage to COOP in that multiple elements and networks can provide cross-support in a seamless manner. The results of trade studies support this assumption but also show that centralization as a means of achieving integration can result in single points of failure that must be mitigated. The cost to provide this mitigation can be substantial. In support of this effort, the team evaluated the current approaches to COOP, developed multiple potential approaches to COOP in a future integrated network, evaluated the interdependencies of the various approaches to the various network control and operations options, and did a best value assessment of the options. The paper will describe the trade space, the study methods, and results of the study.

Anderson, Michael L.; Wright, Nathaniel; Tai, Wallace

2012-01-01

234

Albuquerque Basin seismic network  

USGS Publications Warehouse

The U.S. Geological Survey has recently completed the installation of a seismic network around the Albuquerque Basin in New Mexico. The network consists of two seismometer arrays, a thirteen-station array monitoring an area of approximately 28,000 km 2 and an eight-element array monitoring the area immediately adjacent to the Albuquerque Seismological Laboratory. This report describes the instrumentation deployed in the network.

Jaksha, Lawrence H.; Locke, Jerry; Thompson, J. B.; Garcia, Alvin

1977-01-01

235

Exploring neural network technology  

SciTech Connect

EPRI is funding several projects to explore neural network technology, a form of artificial intelligence that some believe may mimic the way the human brain processes information. This research seeks to provide a better understanding of fundamental neural network characteristics and to identify promising utility industry applications. Results to date indicate that the unique attributes of neural networks could lead to improved monitoring, diagnostic, and control capabilities for a variety of complex utility operations. 2 figs.

Naser, J.; Maulbetsch, J.

1992-12-01

236

A dynamic network architecture  

Microsoft Academic Search

Network software is a critical component of any distributed system. Because of its complexity, network software is commonly layered into a hierarchy of protocols, or more generally, into a protocol graph. Typical protocol graphs—including those standardized in the ISO and TCP\\/IP network architectures—share three important properties; the protocol graph is simple, the nodes of the graph (protocols) encapsulate complex functionality,

Sean W. O'Malley; Larry L. Peterson

1992-01-01

237

Economics Research Network (ERN)  

NSDL National Science Digital Library

Sponsored by the Social Sciences Research Network (for more information, see the November 29, 1999 Scout Report), the Economics Research Network offers abstracts and full-text papers and articles from over 25 economics journals. The journals are searchable through the Social Sciences Research Network's electronic library. ERN lists the economic journals offered in the electronic library, complete with a pithy description of the journal and advisory board members. The site also includes job listings and announcements.

238

The Deep Space Network  

NASA Technical Reports Server (NTRS)

The objectives, functions, and organization, of the Deep Space Network are summarized. Deep Space stations, ground communications, and network operations control capabilities are described. The network is designed for two-way communications with unmanned spacecraft traveling approximately 1600 km from earth to the farthest planets in the solar system. It has provided tracking and data acquisition support for the following projects: Ranger, Surveyor, Mariner, Pioneer, Apollo, Helios, Viking, and the Lunar Orbiter.

1974-01-01

239

Processes on Complex Networks  

NSDL National Science Digital Library

Building on their understanding of graphs, students are introduced to random processes on networks. They walk through an illustrative example to see how a random process can be used to represent the spread of an infectious disease, such as the flu, on a social network of students. This demonstrates how scientists and engineers use mathematics to model and simulate random processes on complex networks. Topics covered include random processes and modeling disease spread, specifically the SIR (susceptible, infectious, resistant) model.

Complex Systems Science Laboratory

240

The deep space network  

NASA Technical Reports Server (NTRS)

The objectives, functions, and organization of the Deep Space Network are summarized along with deep space station, ground communication, and network operations control capabilities. Mission support of ongoing planetary/interplanetary flight projects is discussed with emphasis on Viking orbiter radio frequency compatibility tests, the Pioneer Venus orbiter mission, and Helios-1 mission status and operations. Progress is also reported in tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations.

1975-01-01

241

Composite Random Fiber Networks  

NASA Astrophysics Data System (ADS)

Systems made from fibers are common in the biological and engineering worlds. In many instances, as for example in skin, where elastin and collagen fibers are present, the fiber network is composite, in the sense that it contains fibers of very different properties. The relationship between microstructural parameters and the elastic moduli of random fiber networks containing a single type of fiber is understood. In this work we address a similar target for the composite networks. We show that linear superposition of the contributions to stiffness of individual sub-networks does not apply and interesting non-linear effects are observed. A physical basis of these effects is proposed.

Picu, Catalin; Shahsavari, Ali

2013-03-01

242

Learn More About Networking  

NSDL National Science Digital Library

These are some interesting sites that will help you to understand networking and how it can benefit you. These sites contain sound so you may want to wear headphones if you are in a classroom. Learn how the internet began and the basics of the www. Learn why a network is useful. Jans network contains the important concepts of networking, Work through section 7 to learn about different types of connections, transmissions, media, and configurations. Then take the quiz at the end to see how ...

Watts, Mrs.

2007-10-12

243

Communicability in temporal networks  

NASA Astrophysics Data System (ADS)

A first-principles approach to quantify the communicability between pairs of nodes in temporal networks is proposed. It corresponds to the imaginary-time propagator of a quantum random walk in the temporal network, which accounts for unique structural and temporal characteristics of both streaming and nonstreaming temporal networks. The influence of the system's temperature on the perdurability of information and how the communicability identifies patterns of communication hidden in the temporal and topological structure of the networks are also studied for synthetic and real-world systems.

Estrada, Ernesto

2013-10-01

244

Future Optical Networks  

NASA Astrophysics Data System (ADS)

This paper presents views on the future of optical networking. A historical look at the emergence of optical networking is first taken, followed by a discussion on the drivers pushing for a new and pervasive network, which is based on photonics and can satisfy the needs of a broadening base of residential, business, and scientific users. Regional plans and targets for optical networking are reviewed to understand which current approaches are judged important. Today, two thrusts are driving separate optical network infrastructure models, namely 1) the need by nations to provide a ubiquitous network infrastructure to support all the future services and telecommunication needs of residential and business users and 2) increasing demands by the scientific community for networks to support their requirements with respect to large-scale data transport and processing. This paper discusses these network models together with the key enabling technologies currently being considered for future implementation, including optical circuit, burst and packet switching, and optical code-division multiplexing. Critical subsystem functionalities are also reviewed. The discussion considers how these separate models might eventually merge to form a global optical network infrastructure.

O'Mahony, Michael J.; Politi, Christina; Klonidis, Dimitrios; Nejabati, Reza; Simeonidou, Dimitra

2006-12-01

245

Heterogeneous broadband network  

NASA Astrophysics Data System (ADS)

Although the vision for the future Integrated Broadband Communication Network (IBCN) is an all optical network, it is certain that for a long period to come, the network will remain very heterogeneous, with a mixture of different physical media (fiber, coax and twisted pair), transmission systems (PDH, SDH, ADSL) and transport protocols (TCP/IP, AAL/ATM, frame relay). In the current work towards the IBCN, the ATM concept is considered the generic network protocol for both public and private network, with the ability to use different underlying transmission protocols and, through adaptation protocols, provide the appropriate services (old as well as new) to the customer. One of the major difficulties of heterogeneous network is the restriction that is usually given by the lowest common denominator, e.g. in terms of single channel capacity. A possible way to overcome these limitations is by extending the ATM concept with a multilink capability, that allows us to use separate resources as one common. The improved flexibility obtained by this protocol extension further allows a real time optimization of network and call configuration, without any impact on the quality of service seen from the user. This paper describes an example of an ATM based multilink protocol that has been experimentally implemented within the RACE project 'STRATOSPHERIC'. The paper outlines the complexity of introducing an extra network functionality compared with the added value, such as an improved ability to recover an error due to a malfunctioning network component.

Dittmann, Lars

1995-11-01

246

Mobile Virtual Private Networking  

NASA Astrophysics Data System (ADS)

Mobile Virtual Private Networking (VPN) solutions based on the Internet Security Protocol (IPSec), Transport Layer Security/Secure Socket Layer (SSL/TLS), Secure Shell (SSH), 3G/GPRS cellular networks, Mobile IP, and the presently experimental Host Identity Protocol (HIP) are described, compared and evaluated. Mobile VPN solutions based on HIP are recommended for future networking because of superior processing efficiency and network capacity demand features. Mobile VPN implementation issues associated with the IP protocol versions IPv4 and IPv6 are also evaluated. Mobile VPN implementation experiences are presented and discussed.

Pulkkis, Göran; Grahn, Kaj; Mårtens, Mathias; Mattsson, Jonny

247

Ridge polynomial networks.  

PubMed

This paper presents a polynomial connectionist network called ridge polynomial network (RPN) that can uniformly approximate any continuous function on a compact set in multidimensional input space R (d), with arbitrary degree of accuracy. This network provides a more efficient and regular architecture compared to ordinary higher-order feedforward networks while maintaining their fast learning property. The ridge polynomial network is a generalization of the pi-sigma network and uses a special form of ridge polynomials. It is shown that any multivariate polynomial can be represented in this form, and realized by an RPN. Approximation capability of the RPN's is shown by this representation theorem and the Weierstrass polynomial approximation theorem. The RPN provides a natural mechanism for incremental network growth. Simulation results on a surface fitting problem, the classification of high-dimensional data and the realization of a multivariate polynomial function are given to highlight the capability of the network. In particular, a constructive learning algorithm developed for the network is shown to yield smooth generalization and steady learning. PMID:18263347

Shin, Y; Ghosh, J

1995-01-01

248

Directed network modules  

NASA Astrophysics Data System (ADS)

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 Rényi 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.

Palla, Gergely; Farkas, Illés J.; Pollner, Péter; Derényi, Imre; Vicsek, Tamás

2007-06-01

249

Network of Networks and the Climate System  

NASA Astrophysics Data System (ADS)

Network of networks is a new direction in complex systems science. One can find such networks in various fields, such as infrastructure (power grids etc.), human brain or Earth system. Basic properties and new characteristics, such as cross-degree, or cross-betweenness will be discussed. This allows us to quantify the structural role of single vertices or whole sub-networks with respect to the interaction of a pair of subnetworks on local, mesoscopic, and global topological scales. Next, we consider an inverse problem: Is there a backbone-like structure underlying the climate system? For this we propose a method to reconstruct and analyze a complex network from data generated by a spatio-temporal dynamical system. This technique is then applied to 3-dimensional data of the climate system. We interpret different heights in the atmosphere as different networks and the whole as a network of networks. This approach enables us to uncover relations to global circulation patterns in oceans and atmosphere. The global scale view on climate networks offers promising new perspectives for detecting dynamical structures based on nonlinear physical processes in the climate system. This concept is applied to Indian Monsoon data in order to characterize the regional occurrence of strong rain events and its impact on predictability. References: Arenas, A., A. Diaz-Guilera, J. Kurths, Y. Moreno, and C. Zhou, Phys. Reports 2008, 469, 93. Donges, J., Y. Zou, N. Marwan, and J. Kurths, Europhys. Lett. 2009, 87, 48007. Donner, R., Y. Zou, J. Donges, N. Marwan, and J. Kurths, Phys. Rev. E 2010, 81, 015101(R ). Mokhov, I. I., D. A. Smirnov, P. I. Nakonechny, S. S. Kozlenko, E. P. Seleznev, and J. Kurths, Geophys. Res. Lett. 2011, 38, L00F04. Malik, N., B. Bookhagen, N. Marwan, and J. Kurths, Climate Dynamics, 2012, 39, 971. Donges, J., H. Schultz, N. Marwan, Y. Zou, J. Kurths, Eur. J. Phys. B 2011, 84, 635-651. Donges, J., R. Donner, M. Trauth, N. Marwan, H.J. Schellnhuber, and J. Kurths, PNAS 2011, 108, 20422-20427. Runge, J. , J. Heitzig, V. Petoukhov, J. Kurths, Phys. Rev. Lett. 2012, 108, 258701.

Kurths, Jürgen; Boers, Niklas; Bookhagen, Bodo; Donges, Jonathan; Donner, Reik; Malik, Nishant; Marwan, Norbert; Stolbova, Veronika

2013-04-01

250

An algebraic approach to network coding  

Microsoft Academic Search

We take a new look at the issue of network capacity. It is shown that network coding is an essential ingredient in achieving the capacity of a network. Building on recent work by Li et al., who examined the network capacity of multicast networks, we extend the network coding framework to arbitrary networks and robust networking. For networks which are

Ralf Koetter; Muriel Médard

2003-01-01

251

Internationalisation Network: A Finnish Experience  

ERIC Educational Resources Information Center

One of the main issues of internationalisation is networking. The network way of action within higher education institutions (HEIs) represents new modes of the information work. Networks are worth evaluating more precisely in the future, and social network analysis (SNA) is a useful tool for this evaluation. This article describes the network of…

Kantola, Mauri; Hautala, Jouni

2008-01-01

252

Free space optical wireless network  

Microsoft Academic Search

This talk explore an over the air optical wireless network and to create a network architecture for reliable high data rate free space optical networks that can interoperate with traditional wired and fiber networks. These networks will have significant impact for applications between ships, airborne vehicles, satellites and land-based cloud computing and data centres as an integrated high speed information

Vincent W. S. Chan; Irwin Jacobs; Claude E. Shannon

2011-01-01

253

Library Networks '74-'75.  

ERIC Educational Resources Information Center

Libraries are using computers and telecommunications networks to share resources and centralize processing tasks. Networks allow handling of increasing amounts of material with limited funds. New developments in communications technology encourage network growth. The Ohio College Library Center is the current leader in networking. Network efforts…

Miller, Martin R., Ed.

254

A survey of programmable networks  

Microsoft Academic Search

In this paper we present a programmable networking model that provides a common framework for understanding the state-of-the-art in programmable networks. A number of projects are reviewed and discussed against a set of programmable network characteristics. We believe that a number of important innovations are creating a paradigm shift in networking leading to higher levels of network programmability. These innovations

Andrew T. Campbell; Herman G. De Meer; Michael E. Kounavis; Kazuho Miki; John B. Vicente; Daniel A. Villela

1999-01-01

255

A transport network layer based on optical network elements  

Microsoft Academic Search

An approach to the realization of a broadband, flexible, multiwavelength transport network employing an optical network layer. The design methodology for a network demonstrator is presented, and the transmission, switching, line, and management\\/supervisory subsystems and components are described

G. R. Hill; P. J. Chidgey; Frank Kaufhold; Thomas Lynch; Olof Sahlen; Mattias Gustavsson; M. Janson; B. Lagerstrom; G. Grasso; F. Meli; Sonny Johansson; Joakim Ingers; Lars Fernandez; Salvatore Rotolo; Andrea Antonielli; Sergio Tebaldini; Emilio Vezzoni; R. Caddedu; N. Caponio; F. Testa; A. Scavennec; M. J. O'Mahony; J. Zhou; A. Yu; W. Sohler; U. Rust; H. Herrmann

1993-01-01

256

Network on Target: Remotely Configured Adaptive Tactical Networks.  

National Technical Information Service (NTIS)

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 and analyze data while on the move. The network could e...

A. Bordetsky E. Bourakov

2006-01-01

257

Applications of Disruption Tolerant Networking to Optical Networking in Space.  

National Technical Information Service (NTIS)

The integration of optical communication links into space networks via Disruption Tolerant Networking (DTN) is a largely unexplored area of research. Building on successful foundational work accomplished at JPL, we discuss a multi-hop multi-path network f...

A. G. Hylton D. Iannicca D. E. Raible J. Juergens

2012-01-01

258

Better sales networks.  

PubMed

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. PMID:16846193

Ustüner, Tuba; Godes, David

2006-01-01

259

Connecting Sensor Networks with TCP\\/IP Network  

Microsoft Academic Search

Wireless sensor networks cannot have meaningful work without connecting with TCP\\/IP based network. In this paper, we analyze and compare all the existing solutions for connecting sensor networks with TCP\\/IP network, then based on the analysis result we present the basic design principle and key idea for connecting sensor networks with TCP\\/IP network. After comparing with related researches we claim

Shu Lei; Jin Wang; Hui Xu; Jinsung Cho; Sungyoung Lee

2006-01-01

260

Controlling Across Complex Networks: Emerging Links Between Networks and Control  

Microsoft Academic Search

The presence of communication networks in the feedback path of a control system has led to new problems for control designers.\\u000a Meanwhile, physicists, computer scientists, and mathematicians have been studying the formation and properties of physical\\u000a networks under the heading of complex networks. Control engineers use a network model to facilitate controller design, while\\u000a complex network theorists investigate networks to

Aaron Clauset; Herbert G. Tanner; Chaouki T. Abdallah; Raymond H. Byrne

2006-01-01

261

DNA Structure and Supercoiling: Ribbons and a Yo-Yo Model  

ERIC Educational Resources Information Center

The double-helical structure of DNA is a pop cultural icon. Images of the DNA molecule appear in newspapers, popular journals, and advertisements. In addition to scientific instrument sales, the aura surrounding the central molecule of life has been used to sell everything from perfume to beverages and is the inspiration of items ranging from…

Van Horn, J. David

2011-01-01

262

The Istria yo-yo - evidence for millennial seismic cycle in the northern Adriatic  

NASA Astrophysics Data System (ADS)

The Istria Peninsula in the northern Adriatic Sea (Croatia and Slovenia) is considered to be a nearly aseismic part of the Adriatic microplate, as opposed to the seismically active frontal ranges of the highly active Dinaric orogen. New archaeoseismological data from the Medieval Eufrasius cathedral in Pore? on the west coast of Istria demonstrate two, previously unknown major earthquakes, which occured approx. a millennium apart. Evidence for slow coastal uplift alternating with rapid subsidence allows to identify the seismic cycle. A marine notch, otherwise an excellent marker of sea level, extends along a 240 km segment of the northern Adriatic rocky coast, from Trieste to Zadar. We interpret the following history of vertical displacements: (1) Slow uplift, evidenced by the 1-2 m high, roofed marine notch oversized with respect to the microtidal regime of the Adriatic Sea. 0.5-1 m deep notches were etched into the coast between ~3000 BC until the 4-6th century AD (Faivre et al., 2010). (2) Rapid submergence of the notch to 1-2 m depth below sea level, dated by the construction of successive cathedrals of Pore? built on increasingly higher ground at the seaside (4-6th century AD); submergence of Cissa town on Pag island in 361 AD. (3) Slow uplift of less than 2 m between the construction of the last, Eufrasius cathedral in the 4-6th century AD and the ~1440 AD earthquake. No conspicuous notch were etched in the rocky shore during this period. (4) Rapid submergence of terrestrial sediments below sea level after 1400 AD (Faivre et al., 2011). Major earthquake damage in Pore? cathedral just before 1440 AD. (5) Slow uplift after 1440 AD, corroborated by three decades of high-precision levelling and recent GPS data (Rezo et al., 2010). No conspicuous notch etched in the rocky shore during this period. (6) Next major earthquake with subsidence on land and uplift in the sea with tsunami... when? In our interpretation of the seismic cycle, Istria is slowly raised, about 1-2 m in a millennium, during stress accumulation caused by a locked fault plane. Stress release produces sudden subsidence of the coast, which is recorded by subsided coastal features (marine notch, terrestrial sediments, cathedral of Pore?). We speculate that the thrust fault responsible for the earthquakes lies below the 2-5 km thick Triassic-Cretaceous carbonate platform sequence. The fault plane is assumed to be a gently sloping surface descending towards the east within the Permian-Lower Triassic clastic and evaporite beds. Over the centuries betweeen earthquakes the fault remained locked and the gradually increasing strain was manifested by the uplift (bulging) of the west coast of Istria, whereas the offshore portion of the hanging wall probably bowed downward above the fault. When rupture occurred, the bulge suddenly lowered back to the 'original' elevation. Meanwhile, the bowed, submarine portion of Istria relaxed and possibly triggered a tsunami. Continuing NNW-ward motion of the Adriatic microplate towards Eurasia, well-documented by GPS measurements, provides energy for stress accumulation of the next earthquake cycle. These observations challenge the current notion of Istria as the region of low seismic hazard and invite further paleoseismological research (M.K. OTKA K67.583; M.V. ARRS L1-5452 grant. B.S. contributed as Alexander von Humboldt Research Fellow) References: Faivre et al. (2010): GeoActa, SP 3, 125-134; Faivre et al. (2011): Quat. Int. 232, 132-143; Rezo et al. (2010): EJGE 15, 1835-1847

Kázmér, Miklós; Vrabec, Marko; Székely, Balázs

2014-05-01

263

The Yo-Yo IR2 test: physiological response, reliability, and application to elite soccer.  

PubMed

The purpose of this study was to compare the effects of resistance training performed on either a stable or unstable surface on performance tests in female soccer players. Nineteen National Collegiate Athletic Association Division II female soccer players were assigned to either an unstable training group (UST: 19.0 ± 0.47 years; 1.69 ± 6.4 m; 67.8 ± 7.7 kg) or a stable training group (ST: 19.6 ± 0.49 years; 1.64 ± 3.2 m; 62.7 ± 6.27 kg). Player positions were distributed evenly between the groups. Both the groups followed a 5-week periodized resistance training program designed to develop maximum muscular strength. The groups performed the same exercises during each workout, with the UST performing 2 of the exercises in each session on an unstable surface. Pretraining and posttraining measures of straight-line sprint speed, planned and reactive agility, aerobic capacity, and countermovement vertical jump (CMJ) were taken. Significant main effects for time were reported for straight-line sprint speed, planned agility, and reactive agility with both groups demonstrating improvements during the posttraining testing session. The ST demonstrated a significant increase in CMJ during the posttraining session (change in mean: 0.04 m) in contrast to the decline demonstrated by the UST (change in mean: -0.01 m). Performing resistance training exercises on an unstable surface confers no advantage over traditional resistance training exercises for improving the speed, agility, and aerobic capacity of female soccer players. Furthermore, the use of an unstable surface may inhibit the effects of resistance training on vertical jump height, an important variable in soccer performance. PMID:22130388

Oberacker, Lisa M; Davis, Shala E; Haff, G Gregory; Witmer, Chad A; Moir, Gavin L

2012-10-01

264

A Community Information Network.  

National Technical Information Service (NTIS)

The possibility of creating in Canada a non-profit community information network (a set of linked data banks containing information for use by the general public) should be explored. A network to link together a set of data banks containing information fo...

1971-01-01

265

Network Growth with Feedback  

Microsoft Academic Search

Existing models of network growth typically have one or two parameters or strategies which are fixed for all times. We introduce a general framework where feedback on the current state of a network is used to dynami- cally alter the values of such parameters. A specific model is analyzed where limited resources are shared among arriving nodes, all vying to

Raissa M. D'souza; Soumen Roy

2008-01-01

266

Wireless Ad Hoc Networks  

Microsoft Academic Search

A mobile ad hoc network is a relatively new term for an old technology - a network that does not rely on p re-existing infrastructure. Roots of this technology could be traced back to the early 1970s with the DARPA PRNet and the SURAN projects. The new twitch is the application of this technology in the non-military communication environments. Additionally,

Zygmunt J. Haas; Jing Deng; Ben Liang; Panagiotis Papadimitratos; S. Sajama

2002-01-01

267

Reciprocity of weighted networks.  

PubMed

In directed networks, reciprocal links have dramatic effects on dynamical processes, network growth, and higher-order structures such as motifs and communities. While the reciprocity of binary networks has been extensively studied, that of weighted networks is still poorly understood, implying an ever-increasing gap between the availability of weighted network data and our understanding of their dyadic properties. Here we introduce a general approach to the reciprocity of weighted networks, and define quantities and null models that consistently capture empirical reciprocity patterns at different structural levels. We show that, counter-intuitively, previous reciprocity measures based on the similarity of mutual weights are uninformative. By contrast, our measures allow to consistently classify different weighted networks according to their reciprocity, track the evolution of a network's reciprocity over time, identify patterns at the level of dyads and vertices, and distinguish the effects of flux (im)balances or other (a)symmetries from a true tendency towards (anti-)reciprocation. PMID:24056721

Squartini, Tiziano; Picciolo, Francesco; Ruzzenenti, Franco; Garlaschelli, Diego

2013-01-01

268

Local Area Networks.  

ERIC Educational Resources Information Center

Discusses cabling that is needed in local area networks (LANs). Types of cables that may be selected are described, including twisted pair, coaxial cables (or ethernet), and fiber optics; network topologies, the manner in which the cables are laid out, are considered; and cable installation issues are discussed. (LRW)

Marks, Kenneth E.; Nielsen, Steven

1991-01-01

269

Resilient network admission control  

Microsoft Academic Search

In this paper we give an overview of different network admission control (NAC) approaches that can be used to assure QoS in networks with real-time traffic. They differ in the number and location of the required admission control (AC) decisions per flow, the resulting state maintenance, as well as the scope of an AC entity regarding its flow bundle sizes.

Michael Menth; Stefan Kopf; Joachim Charzinski; Karl J. Schrodi

2008-01-01

270

Community Wireless Networks  

ERIC Educational Resources Information Center

With increasing frequency, communities are seeing the arrival of a new class of noncommercial broadband providers: community wireless networks (CWNs). Utilizing the same wireless technologies that many colleges and universities have used to create wireless networks on campus, CWNs are creating broadband access for free or at costs well below…

Feld, Harold

2005-01-01

271

Broadband network selection issues  

Microsoft Academic Search

Selecting the best network for a given cable or telephone company provider is not as obvious as it appears. The cost and performance trades between Hybrid Fiber Coax (HFC), Fiber to the Curb (FTTC) and Asymmetric Digital Subscriber Line networks lead to very different choices based on the existing plant and the expected interactive subscriber usage model. This paper presents

Michael E. Leimer

1996-01-01

272

Wireless Sensor Networks Approach  

NASA Technical Reports Server (NTRS)

This viewgraph presentation provides information on hardware and software configurations for a network architecture for sensors. The hardware configuration uses a central station and remote stations. The software configuration uses the 'lost station' software algorithm. The presentation profiles a couple current examples of this network architecture in use.

Perotti, Jose M.

2003-01-01

273

PESTICIDE INFORMATION NETWORK  

EPA Science Inventory

The Pesticide Information Network (PIN) is an interactive database containing information about pesticides. PIN is a free service offered by the USEPAs Office of Pesticide Programs which provides contacts on pesticide issues, has a bulletin board network for public and private us...

274

The protein folding network  

NASA Astrophysics Data System (ADS)

Networks are everywhere. The conformation space of a 20-residue antiparallel beta-sheet peptide [1], sampled by molecular dynamics simulations, is mapped to a network. Conformations are nodes of the network, and the transitions between them are links. As previously found for the World-Wide Web as well as for social and biological networks , the conformation space contains highly connected hubs like the native state which is the most populated free energy basin. Furthermore, the network shows a hierarchical modularity [2] which is consistent with the funnel mechanism of folding [3] and is not observed for a random heteropolymer lacking a native state. Here we show that the conformation space network describes the free energy landscape without requiring projections into arbitrarily chosen reaction coordinates. The network analysis provides a basis for understanding the heterogeneity of the folding transition state and the existence of multiple pathways. [1] P. Ferrara and A. Caflisch, Folding simulations of a three-stranded antiparallel beta-sheet peptide, PNAS 97, 10780-10785 (2000). [2] Ravasz, E. and Barabási, A. L. Hierarchical organization in complex networks. Phys. Rev. E 67, 026112 (2003). [3] Dill, K. and Chan, H From Levinthal to pathways to funnels. Nature Struct. Biol. 4, 10-19 (1997)

Rao, Francesco; Caflisch, Amedeo

2004-03-01

275

The Deep Space Network  

NASA Technical Reports Server (NTRS)

Deep Space Network progress in flight project support, tracking and data acquisition, research and technology, network engineering, hardware and software implementation, and operations is cited. Topics covered include: tracking and ground based navigation; spacecraft/ground communication; station control and operations technology; ground communications; and deep space stations.

1979-01-01

276

Arkansas Cancer Community Network  

Cancer.gov

The Arkansas Cancer Community Network (AR-CCN) at the University of Arkansas for Medical Sciences1 seeks to build upon the accomplishments of the Arkansas Special Populations Access Network (ASPAN) for the continued development and implementation of community-based participatory research and training programs.

277

Nanoporous organic polymer networks  

Microsoft Academic Search

Nanoporous organic polymer networks are a class of materials consisting solely of the lighter elements in the periodic table. These materials have potential uses in areas such as storage, separation, and catalysis. Here, we review the different classes of nanoporous polymer networks including covalent organic frameworks, hypercrosslinked polymers, conjugated microporous polymers, and polymers of intrinsic microporosity. The growing variety in

Robert Dawson; Andrew I. Cooper; Dave J. Adams

278

Student Observation Network DVD  

NSDL National Science Digital Library

This DVD is meant to be given to educators after the 16 hour training on the Tracking a Solar Storm Module of NASA's Student Observation Network. It was created to be used as a resource for content about solar storms and a quick refresher of the modules available through the Student Observation Network.

2004-01-01

279

Coherent optical CDMA networks  

Microsoft Academic Search

Recent work in optical code-division multiple access (CDMA) is reviewed, progressing from incoherent to coherent techniques. It is shown that under appropriate conditions, coherent CDMA can in principle rival wavelength-division multiplexing (WDM) in terms of aggregate network throughput. Furthermore, it is shown that at high data rates, some of the components for WDM are coherent CDMA networks are nearly identical,

Michel E. Marhic

1993-01-01

280

Wireless Sensors Network (Sensornet)  

NASA Technical Reports Server (NTRS)

The Wireless Sensor Network System presented in this paper provides a flexible reconfigurable architecture that could be used in a broad range of applications. It also provides a sensor network with increased reliability; decreased maintainability costs, and assured data availability by autonomously and automatically reconfiguring to overcome communication interferences.

Perotti, J.

2003-01-01

281

BES Science Network Requirements.  

National Technical Information Service (NTIS)

The Energy Sciences Network (ESnet) is the primary provider of network connectivity for the US Department of Energy Office of Science (SC), the single largest supporter of basic research in the physical sciences in the United States. In support of the Off...

B. Tierney C. Mundy E. Dart E. Dart M. Lamm S. Miller

2011-01-01

282

SCTP in battlefield networks  

Microsoft Academic Search

The Stream Control Transmission Protocol (SCTP) is a new Internet standards track transport layer protocol SCTP was originally designed to transport PSTN signaling messages over IP networks, but is also capable of serving as a general purpose transport protocol. As such, SCTP provides an alternative that may be better able to satisfy the requirements of future battlefield networks than the

Phillip T. Conrad; Gerard J. Heinz; Armando L. Caro Jr; Paul D. Amer; John Fiore

2001-01-01

283

UNESCO as a Network  

ERIC Educational Resources Information Center

This study attempts to draw attention to the hitherto neglected, but important, subject of how the United Nations Educational, Scientific, and Cultural Organization (UNESCO), as a network and promoter of other networks, has sought to foster the spirit of cooperation, understanding and partnership among its various Member States through…

Omolewa, Michael

2007-01-01

284

Information Network Development.  

ERIC Educational Resources Information Center

The International Bureau of Education (IBE) and Unesco, together with their member states, are faced with the task of implementing a proposed network--the International Network for Educational Information (INED)--for the better use of information resources for educational development. This review of issues that need to be considered in the…

Mahon, F. V.

285

Typologies of attentional networks  

Microsoft Academic Search

Attention is a central theme in cognitive science — it exemplifies the links between the brain and behaviour, and binds psychology to the techniques of neuroscience. A visionary model suggested by Michael Posner described attention as a set of independent control networks. This challenged the previously held view of attention as a uniform concept. The idea that disparate attentional networks

Jason Buhle; Amir Raz

2006-01-01

286

Security of Sensor Networks.  

National Technical Information Service (NTIS)

This thesis discusses the security of sensor networks. First, descriptions of the security architectures of two dominant sensor network implementations in the market today are presented: the TinyOS stack and the IEEE 802.15.4 stack. Their similarities and...

H. Teo

2006-01-01

287

On Heterogeneous Covert Networks  

NASA Astrophysics Data System (ADS)

Covert organizations are constantly faced with a tradeoff between secrecy and operational efficiency. Lindelauf, Borm and Hamers [13] developed a theoretical framework to determine optimal homogeneous networks taking the above mentioned considerations explicitly into account. In this paper this framework is put to the test by applying it to the 2002 Jemaah Islamiyah Bali bombing. It is found that most aspects of this covert network can be explained by the theoretical framework. Some interactions however provide a higher risk to the network than others. The theoretical framework on covert networks is extended to accommodate for such heterogeneous interactions. Given a network structure the optimal location of one risky interaction is established. It is shown that the pair of individuals in the organization that should conduct the interaction that presents the highest risk to the organization, is the pair that is the least connected to the remainder of the network. Furthermore, optimal networks given a single risky interaction are approximated and compared. When choosing among a path, star and ring graph it is found that for low order graphs the path graph is best. When increasing the order of graphs under consideration a transition occurs such that the star graph becomes best. It is found that the higher the risk a single interaction presents to the covert network the later this transition from path to star graph occurs.

Lindelauf, Roy; Borm, Peter; Hamers, Herbert

288

Immunization of complex networks  

Microsoft Academic Search

Complex networks such as the sexual partnership web or the Internet often show a high degree of redundancy and heterogeneity in their connectivity properties. This peculiar connectivity provides an ideal environment for the spreading of infective agents. Here we show that the random uniform immunization of individuals does not lead to the eradication of infections in all complex networks. Namely,

Romualdo Pastor-Satorras; Alessandro Vespignani

2002-01-01

289

Hanford Seismic Network  

SciTech Connect

This report describes the Hanford Seismic Network. The network consists of two instrument arrays: seismometers and strong motion accelerometers. The seismometers determine the location and magnitude of earthquakes, and the strong motion accelerometers determine ground motion. Together these instruments arrays comply with the intent of DOE Order 5480.20, Natural Phenomena Hazards Mitigation.

Reidel, S.P.; Hartshorn, D.C.

1997-05-01

290

The Deep Space Network  

NASA Technical Reports Server (NTRS)

The Deep Space Network (DSN) is the largest and most sensitive scientific telecommunications and radio navigation network in the world. Its principal responsibilities are to support unmanned interplanetary spacecraft missions and to support radio and radar astronomy observations in the exploration of the solar system and the universe. The DSN facilities and capabilities as of January 1988 are described.

1988-01-01

291

TOXNET (TOXICOLOGY DATA NETWORK)  

EPA Science Inventory

TOXNET (Toxicology Data Network) is a computerized system of files oriented to toxicology and related areas. It is managed by the National Library of Medicines Toxicology and Environmental Health Information Program (TEHIP) and runs on a series of microcomputers in a networked cl...

292

Early Detection Research Network  

Cancer.gov

This initiative supports the creation of a national Network for early cancer detection with resources for translational research that will include laboratory science, clinical science, public health, biostatistics, informatics, and computer science. The goals of the Network are to discover and coordinate the evaluation of biomarkers and reagents for the earlier detection of cancer and for the assessment of risk.

293

CAISSON: Interconnect Network Simulator  

NASA Technical Reports Server (NTRS)

Cray response to HPCS initiative. Model future petaflop computer interconnect. Parallel discrete event simulation techniques for large scale network simulation. Built on WarpIV engine. Run on laptop and Altix 3000. Can be sized up to 1000 simulated nodes per host node. Good parallel scaling characteristics. Flexible: multiple injectors, arbitration strategies, queue iterators, network topologies.

Springer, Paul L.

2006-01-01

294

Network Architecture Evolution: towards \\  

Microsoft Academic Search

New services, new applications, new profiles of clients, new networking technologies and new forms of communications, such as peer-to-peer, and media\\/content-to-person, are all driving the need for a converged all-IP network that can provide an \\

Roberto Sabella

2007-01-01

295

Superpositional Quantum Network Topologies  

Microsoft Academic Search

We introduce superposition-based quantum networks composed of (i) the classical perceptron model of multilayered, feedforward neural networks and (ii) the algebraic model of evolving reticular quantum structures as described in quantum gravity. The main feature of this model is moving from particular neural topologies to a quantum metastructure which embodies many differing topological patterns. Using quantum parallelism, training is possible

Christopher Altman; Jaroslaw Pykacz; Romàn R. Zapatrin

2004-01-01

296

Evolving neural networks  

Microsoft Academic Search

Neural networks are parallel processing structures that provide the capability to perform various pattern recognition tasks. A network is typically trained over a set of exemplars by adjusting the weights of the interconnections using a back propagation algorithm. This gradient search converges to locally optimal solutions which may be far removed from the global optimum. In this paper, evolutionary programming

D. B. Fogel; L. J. Fogel; V. W. Porto

1990-01-01

297

Networking: A Trainer's Manual.  

ERIC Educational Resources Information Center

Intended as a resource for people interested in intiating or promoting networking and collaboration, this manual evolved from a federally funded training project of the Community Education Resource Center (CERC) at the University of Massachusetts. While the theories and activities described are designed to aid in the building of networks in the…

Brandon, Joan M., Ed.; And Others

298

Optimising Networks Against Malware  

Microsoft Academic Search

Rapidly-spreading malicious software is an important threat on today's computer networks. Most solutions that have been proposed to counter this threat are based on our ability to quickly detect the malware-generated traffic or the malware instances themselves, something that in many cases can be beyond our ability. Nonetheless, it seems intu- itive that certain defensive postures adopted in configuring networks

Pierre-marc Bureau; José M. Fernandez

2007-01-01

299

Networking Systems and Equipment.  

ERIC Educational Resources Information Center

Describes how high-bandwidth networks are delivering new educational and administrative opportunities for K-12 school districts. Addresses implementing the new network, upgrading to a switched environment, adding intelligent switches, IP telephony, and wireless technology. Describes deployment and benefits of broadband in the Denver public schools…

Kranz, Maciej

2002-01-01

300

Virtual private networks  

Microsoft Academic Search

A virtual private network (VPN) can help resolve many of the issues associated with today's private networks. A VPN facilitates an agile IT infrastructure. Global VPNs enable connectivity to all locations anywhere in the world at a fraction of the cost of dedicated links. VPN services enable remote access to the intranet at significantly lower cost, thus enabling support for

R. Venkateswaran

2001-01-01

301

Neural networks at work  

Microsoft Academic Search

The benefits of neural networks and the types of application for which they are suited are outlined. Four representative applications are described in enough detail to show how they work. They are character recognition, function estimation, financial forecasting, and process control. Factors that have slowed the acceptance of neural networks are discussed. Hardware is briefly considered

D. Hammerstrom

1993-01-01

302

The Ohio Seismic Network  

Microsoft Academic Search

In January 1999, the Ohio Seismic Network (OhioSeis) began operations with an initial deployment of 15 sta- tions at colleges, universities, and other institutions in various parts of the state. Funding for the network was provided by the Ohio Emergency Management Agency with Federal Emergency Management Agency Funds for earthquake mitigation. The Ohio Geological Survey as- sumed the responsibility for

Michael C. Hansen; Larry J. Ruff

2003-01-01

303

Social Insect Networks  

NSDL National Science Digital Library

Social insect colonies have many of the properties of adaptive networks. The simple rules governing how local interactions among individuals translate into group behaviors are found across social groups, giving social insects the potential to have a profound impact on our understanding of the interplay between network dynamics and social evolution.

Jennifer Fewell (Arizona State University;School of Life Sciences)

2003-09-26

304

Networking digital video  

Microsoft Academic Search

Fluent Machines Inc., has developed Fluency, a system architecture for digital video consisting of FluentStreams system software, FluentLinks network software and the VSA-1000 digital video system hardware. The author presents the technical challenges inherent in networking digital video, and describes how Fluent's system architecture is designed to meet these requirements

P. Uppaluru

1992-01-01

305

The deep space network  

NASA Technical Reports Server (NTRS)

The progress is reported of Deep Space Network (DSN) research in the following areas: (1) flight project support, (2) spacecraft/ground communications, (3) station control and operations technology, (4) network control and processing, and (5) deep space stations. A description of the DSN functions and facilities is included.

1974-01-01

306

Smart networked cities?  

Microsoft Academic Search

This paper aims to critically assess the lack of a global inter-urban perspective in the smart city policy framework from a conceptual standpoint. We argue here that the smart city policy agenda should be informed by and address the structure of transnational urban networks as this can affect the efficiency of such local policies. The significance of this global network

Emmanouil Tranos; Drew Gertner

2012-01-01

307

Hubless satellite communications networks  

NASA Technical Reports Server (NTRS)

Frequency Comb Multiple Access (FCMA) is a new combined modulation and multiple access method which will allow cheap hubless Very Small Aperture Terminal (VSAT) networks to be constructed. Theoretical results show bandwidth efficiency and power efficiency improvements over other modulation and multiple access methods. Costs of the VSAT network are reduced dramatically since a hub station is not required.

Robinson, Peter Alan

1994-01-01

308

A Recursive Network Architecture  

Microsoft Academic Search

The Recursive Network Architecture (RNA) explores the relationship of layering to protocol and network architecture. RNA examines the implications of using a single, tunable protocol for different layers of the protocol stack, reusing basic protocol operations across different protocol layers to avoid reimplementation. Its primary goal is to encourage cleaner cross-layer interaction and to support dynamic service composition, and to

Joseph D. Touch; Yu-Shun Wang; Venkata Pingali

2006-01-01

309

Network vulnerability analysis  

Microsoft Academic Search

The increasing volume of attacks on the Internet has increased the demand for sophisticated tools for vulnerability analysis, intrusion detection, forensic investigations, and possible responses. Current hacker tools and technologies warrant reengineering to address cyber crime and homeland security. The creation of network scanners is necessary to secure the information infrastructure by gathering network topology, intelligence, internal\\/external vulnerability analysis, and

B. Skaggs; B. Blackburn; G. Manes; S. Shenoi

2002-01-01

310

On compressing social networks  

Microsoft Academic Search

Motivated by structural properties of the Web graph that support efficient data structures for in memory adjacency queries, we study the extent to which a large network can be compressed. Boldi and Vigna (WWW 2004), showed that Web graphs can be compressed down to three bits of storage per edge; we study the compressibility of social networks where again adjacency

Flavio Chierichetti; Ravi Kumar; Silvio Lattanzi; Michael Mitzenmacher; Alessandro Panconesi; Prabhakar Raghavan

2009-01-01

311

Telecommunications network optimization  

NASA Technical Reports Server (NTRS)

Analysis discusses STACOM (state criminal justic communication) network topology program used to design and evaluate digital telecommunications networks STACOM employs ESAU-WILLIAMS technique to search for direct links between system terminations and regional switching center. Inputs include traffic data, terminal locations, and functional requirements.

Lee, J.

1979-01-01

312

Implementing Collaboration Process Networks  

Microsoft Academic Search

The promise of process integration between organizations too often is unfulfilled and new approaches are needed. Distributed control is a new and exciting opportunity to build more effective process networks for a wide range of applications in logistics and product development. A solution based on distributed control around the consumers of services in process networks is proposed. In logistics, it

Jan Holmström; Kary Främling; Jukka Tuomi; Mikko Kärkkäinen; Timo Ala-Risku

2002-01-01

313

Neural Networks for Speech Application.  

National Technical Information Service (NTIS)

This is a general introduction to the reemerging technology called neural networks, and how these networks may provide an important alternative to traditional forms of computing in speech applications. Neural networks, sometimes called Artificial Neural S...

S. A. Luse

1987-01-01

314

American Samoa Community Cancer Network  

Cancer.gov

American Samoa Community Cancer Network  Back to CRCHD Ongoing Research CNP Project Listing American Samoa Community Cancer Network CNP Pilot Projects American Samoa Community Cancer Network PRINCIPAL INVESTIGATOR: Victor T. Williams Tofaeono,

315

Optimal Simulations by Butterfly Networks.  

National Technical Information Service (NTIS)

The power of Butterfly-type networks relative to other proposed multicomputer interconnection networks is studied, by considering how efficiently the Butterfly can simulate the other networks. Simulation is represented formally via graph embeddings, so th...

A. L. Rosenberg F. R. Chung F. T. Leighton J. W. Hong S. N. Bhatt

1988-01-01

316

Survey of Network Visualization Tools.  

National Technical Information Service (NTIS)

As a first step in determining the way ahead for research and development of network visualisation techniques, a product and literature search of network visualisation technologies was conducted. The contractors developed a taxonomy of network visualisati...

A. Gort J. Gort

2007-01-01

317

The Gaussian parallel relay network  

Microsoft Academic Search

We introduce the real, discrete-time Gaussian parallel relay network. This simple network is theoretically important in the context of network information theory. We present upper and lower bounds to capacity and explain where they coincide

B. Schein; R. Gallager

2000-01-01

318

Calibrating an Active Network Node.  

National Technical Information Service (NTIS)

Active Network technology envisions deployment of virtual execution environments within network elements, so that nonhomogeneous processing can be applied to network traffic. For management purposes, each node must have a meaningful understanding of resou...

A. Rukhin K. L. Mills S. Leigh V. Galtier Y. Carlinet

2000-01-01

319

Optical Access Networks  

NASA Astrophysics Data System (ADS)

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 have been receiving tremendous attention from both academia and industry. A large number of research activities have been carried out or are now underway this hot area. The purpose of this feature issue is to expose the networking community to the latest research breakthroughs and progresses in the area of optical access networks.

Scope of Contributions

This feature issue aims to present a collection of papers that focus on the state-of-the-art research in various networking aspects of optical access networks. Original papers are solicited from all researchers involved in area of optical access networks. Topics of interest include but not limited to:
  • Optical access network architectures and protocols
  • Passive optical networks (BPON, EPON, GPON, etc.)
  • Active optical networks
  • Multiple access control
  • Multiservices and QoS provisioning
  • Network survivability
  • Field trials and standards
  • Performance modeling and analysis

Manuscript Submission

To submit to this special issue, follow the normal procedure for submission to JON, indicating ``Optical Access Networks feature' in the ``Comments' field of the online submission form. For all other questions relating to this feature issue, please send an e-mail to jon@osa.org, subject line ``Optical Access Networks' Additional information can be found on the JON website: http://www.osa-jon.org/submission/. Submission Deadline: 1 June 2005

Zheng, Jun; Ansari, Nirwan

2005-01-01

320

Networks in cognitive science.  

PubMed

Networks of interconnected nodes have long played a key role in Cognitive Science, from artificial neural networks to spreading activation models of semantic memory. Recently, however, a new Network Science has been developed, providing insights into the emergence of global, system-scale properties in contexts as diverse as the Internet, metabolic reactions, and collaborations among scientists. Today, the inclusion of network theory into Cognitive Sciences, and the expansion of complex-systems science, promises to significantly change the way in which the organization and dynamics of cognitive and behavioral processes are understood. In this paper, we review recent contributions of network theory at different levels and domains within the Cognitive Sciences. PMID:23726319

Baronchelli, Andrea; Ferrer-i-Cancho, Ramon; Pastor-Satorras, Romualdo; Chater, Nick; Christiansen, Morten H

2013-07-01

321

Data networks reliability  

NASA Astrophysics Data System (ADS)

The research from 1984 to 1986 on Data Network Reliability had the objective of developing general principles governing the reliable and efficient control of data networks. The research was centered around three major areas: congestion control, multiaccess networks, and distributed asynchronous algorithms. The major topics within congestion control were the use of flow control algorithms. The major topics within congestion control were the use of flow control to reduce congestion and the use of routing to reduce congestion. The major topics within multiaccess networks were the communication properties of multiaccess channels, collision resolution, and packet radio networks. The major topics within asynchronous distributed algorithms were failure recovery, time vs. communication tradeoffs, and the general theory of distributed algorithms.

Gallager, Robert G.

1988-10-01

322

Semaphore network encryption report  

NASA Astrophysics Data System (ADS)

This paper documents the results of a preliminary assessment performed on the commercial off-the-shelf (COTS) Semaphore Communications Corporation (SCC) Network Security System (NSS). The Semaphore NSS is a family of products designed to address important network security concerns, such as network source address authentication and data privacy. The assessment was performed in the INFOSEC Core Integration Laboratory, and its scope was product usability focusing on interoperability and system performance in an existing operational network. Included in this paper are preliminary findings. Fundamental features and functionality of the Semaphore NSS are identified, followed by details of the assessment, including test descriptions and results. A summary of test results and future plans are also included. These findings will be useful to those investigating the use of commercially available solutions to network authentication and data privacy.

Johnson, Karen L.

1994-03-01

323

Neural networks for aircraft control  

NASA Technical Reports Server (NTRS)

Current research in Artificial Neural Networks indicates that networks offer some potential advantages in adaptation and fault tolerance. This research is directed at determining the possible applicability of neural networks to aircraft control. The first application will be to aircraft trim. Neural network node characteristics, network topology and operation, neural network learning and example histories using neighboring optimal control with a neural net are discussed.

Linse, Dennis

1990-01-01

324

Improved Autoassociative Neural Networks  

NASA Technical Reports Server (NTRS)

Improved autoassociative neural networks, denoted nexi, have been proposed for use in controlling autonomous robots, including mobile exploratory robots of the biomorphic type. In comparison with conventional autoassociative neural networks, nexi would be more complex but more capable in that they could be trained to do more complex tasks. A nexus would use bit weights and simple arithmetic in a manner that would enable training and operation without a central processing unit, programs, weight registers, or large amounts of memory. Only a relatively small amount of memory (to hold the bit weights) and a simple logic application- specific integrated circuit would be needed. A description of autoassociative neural networks is prerequisite to a meaningful description of a nexus. An autoassociative network is a set of neurons that are completely connected in the sense that each neuron receives input from, and sends output to, all the other neurons. (In some instantiations, a neuron could also send output back to its own input terminal.) The state of a neuron is completely determined by the inner product of its inputs with weights associated with its input channel. Setting the weights sets the behavior of the network. The neurons of an autoassociative network are usually regarded as comprising a row or vector. Time is a quantized phenomenon for most autoassociative networks in the sense that time proceeds in discrete steps. At each time step, the row of neurons forms a pattern: some neurons are firing, some are not. Hence, the current state of an autoassociative network can be described with a single binary vector. As time goes by, the network changes the vector. Autoassociative networks move vectors over hyperspace landscapes of possibilities.

Hand, Charles

2003-01-01

325

Measuring network security using dynamic bayesian network  

Microsoft Academic Search

Given the increasing dependence of our societies on networked in- formation systems, the overall security of these systems should be measured and improved. Existing security metrics have generally focused on measuring individual vulnerabilities without consider- ing their combined effects. Our previous work tackle this issue by exploring the causal relationships between vulnerabilities encoded in an attack graph. However, the evolving

Marcel Frigault; Lingyu Wang; Anoop Singhal; Sushil Jajodia

2008-01-01

326

Tinnitus: network pathophysiology-network pharmacology  

PubMed Central

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.

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

2012-01-01

327

Wireless Network Testbed for Stochastic Network Optimization.  

National Technical Information Service (NTIS)

This is an infrastructure development project for a new laboratory at Princeton, now called the Princeton EDGE Lab. Latest updates can be found at http://scenic.princeton.edu. The Princeton EDGE Lab has experimental facilities to study edge networking, wi...

M. Chiang

2010-01-01

328

Constructing stochastic networks via ?-RBF networks  

Microsoft Academic Search

Without considering spatial, stochastic, and temporal features inherent in natural neural systems, the computational power of conventional artificial neural networks (ANNs) is limited. In the present paper, we look at the stochastic complexity and construct a stochastic ANN by modeling stochastic fluctuations in the environmental stimuli such that all stimuli are prone to be corrupted by noise or even outliers

Shong-Tun Li; Ernst L. Leiss

1996-01-01

329

Structures of Semantic Networks: Similarities between Semantic Networks and Brain Networks  

Microsoft Academic Search

Two networks were extracted from two large semantic networks, HowNet and synsets of WordNet, based on conceptual relations. Analysis of these networks shows that they are complex networks with features of small-world and scale-free. Results also show that semantic networks are similar to brain networks: (a) exponents of power law degree distributions are between 1.0 and 2.0, while exponents of

Lu Tang; Yong Guang Zhang; Xue Fu

2006-01-01

330

Markets on Networks  

NASA Astrophysics Data System (ADS)

The dynamics of human, and most biological populations is characterized by competition for resources. By its own nature, this dynamics creates the group of "elites", formed by those agents who have strategies that are the most successful in the given situation, and therefore the rest of the agents will tend to follow, imitate, or interact with them, creating a social structure of leadership in the agent society. These inter-agent communications generate a complex social network with small-world character which itself forms the substrate for a second network, the action network. The latter is a highly dynamic, adaptive, directed network, defined by those inter-agent communication links on the substrate along which the passed information /prediction is acted upon by the other agents. By using the minority game for competition dynamics, here we show that when the substrate network is highly connected, the action network spontaneously develops hubs with a broad distribution of out-degrees, defining a robust leadership structure that is scale-free. Furthermore, in certain, realistic parameter ranges, facilitated by information passing on the action network, agents can spontaneously generate a high degree of cooperation making the collective almost maximally efficient.

Toroczkai, Zoltan; Anghel, Marian; Bassler, Kevin; Korniss, Gyorgy

2003-03-01

331

Simulated Associating Polymer Networks  

NASA Astrophysics Data System (ADS)

Telechelic associating polymer networks consist of polymer chains terminated by endgroups that have a different chemical composition than the polymer backbone. When dissolved in a solution, the endgroups cluster together to form aggregates. At low temperature, a strongly connected reversible network is formed and the system behaves like a gel. Telechelic networks are of interest since they are representative for biopolymer networks (e.g. F-actin) and are widely used in medical applications (e.g. hydrogels for tissue engineering, wound dressings) and consumer products (e.g. contact lenses, paint thickeners). In this thesis such systems are studied by means of a molecular dynamics/Monte Carlo simulation. At first, the system in rest is studied by means of graph theory. The changes in network topology upon cooling to the gel state, are characterized. Hereto an extensive study of the eigenvalue spectrum of the gel network is performed. As a result, an in-depth investigation of the eigenvalue spectra for spatial ER, scale-free, and small-world networks is carried out. Next, the gel under the application of a constant shear is studied, with a focus on shear banding and the changes in topology under shear. Finally, the relation between the gel transition and percolation is discussed.

Billen, Joris

332

Wireless mesh networks.  

PubMed

Wireless telemedicine using GSM and GPRS technologies can only provide low bandwidth connections, which makes it difficult to transmit images and video. Satellite or 3G wireless transmission provides greater bandwidth, but the running costs are high. Wireless networks (WLANs) appear promising, since they can supply high bandwidth at low cost. However, the WLAN technology has limitations, such as coverage. A new wireless networking technology named the wireless mesh network (WMN) overcomes some of the limitations of the WLAN. A WMN combines the characteristics of both a WLAN and ad hoc networks, thus forming an intelligent, large scale and broadband wireless network. These features are attractive for telemedicine and telecare because of the ability to provide data, voice and video communications over a large area. One successful wireless telemedicine project which uses wireless mesh technology is the Emergency Room Link (ER-LINK) in Tucson, Arizona, USA. There are three key characteristics of a WMN: self-organization, including self-management and self-healing; dynamic changes in network topology; and scalability. What we may now see is a shift from mobile communication and satellite systems for wireless telemedicine to the use of wireless networks based on mesh technology, since the latter are very attractive in terms of cost, reliability and speed. PMID:19047448

Wang, Xinheng

2008-01-01

333

Comparative analysis of collaboration networks  

SciTech Connect

In this paper we carry out a comparative analysis of the word network as the collaboration network based on the novel by M. Bulgakov 'Master and Margarita', the synonym network of the Russian language as well as the Russian movie actor network. We have constructed one-mode projections of these networks, defined degree distributions for them and have calculated main characteristics. In the paper a generation algorithm of collaboration networks has been offered which allows one to generate networks statistically equivalent to the studied ones. It lets us reveal a structural correlation between word network, synonym network and movie actor network. We show that the degree distributions of all analyzable networks are described by the distribution of q-type.

Progulova, Tatiana; Gadjiev, Bahruz [International University for Nature, Society and Man, 19 Universitetskaya Street, Dubna, 141980 (Russian Federation)

2011-03-14

334

Networking Technology and Systems (NeTS)  

NSF Publications Database

The network systems underlying these projects include mobile wireless networks and systems; integrated, dynamically configurable optical networks; innovative satellite networking technologies; and broadband access architectures for home networking. The Networking of Sensor Systems focus area is concerned with the design and development of protocols, operating systems, and network architectures that facilitate constructing networks of sensor systems. Projects on physical sensing devices, ...

335

Functional Molecular Ecological Networks  

PubMed Central

Biodiversity and its responses to environmental changes are central issues in ecology and for society. Almost all microbial biodiversity research focuses on “species” richness and abundance but not on their interactions. Although a network approach is powerful in describing ecological interactions among species, defining the network structure in a microbial community is a great challenge. Also, although the stimulating effects of elevated CO2 (eCO2) on plant growth and primary productivity are well established, its influences on belowground microbial communities, especially microbial interactions, are poorly understood. Here, a random matrix theory (RMT)-based conceptual framework for identifying functional molecular ecological networks was developed with the high-throughput functional gene array hybridization data of soil microbial communities in a long-term grassland FACE (free air, CO2 enrichment) experiment. Our results indicate that RMT is powerful in identifying functional molecular ecological networks in microbial communities. Both functional molecular ecological networks under eCO2 and ambient CO2 (aCO2) possessed the general characteristics of complex systems such as scale free, small world, modular, and hierarchical. However, the topological structures of the functional molecular ecological networks are distinctly different between eCO2 and aCO2, at the levels of the entire communities, individual functional gene categories/groups, and functional genes/sequences, suggesting that eCO2 dramatically altered the network interactions among different microbial functional genes/populations. Such a shift in network structure is also significantly correlated with soil geochemical variables. In short, elucidating network interactions in microbial communities and their responses to environmental changes is fundamentally important for research in microbial ecology, systems microbiology, and global change.

Zhou, Jizhong; Deng, Ye; Luo, Feng; He, Zhili; Tu, Qichao; Zhi, Xiaoyang

2010-01-01

336

Attractor Metabolic Networks  

PubMed Central

Background The experimental observations and numerical studies with dissipative metabolic networks have shown that cellular enzymatic activity self-organizes spontaneously leading to the emergence of a Systemic Metabolic Structure in the cell, characterized by a set of different enzymatic reactions always locked into active states (metabolic core) while the rest of the catalytic processes are only intermittently active. This global metabolic structure was verified for Escherichia coli, Helicobacter pylori and Saccharomyces cerevisiae, and it seems to be a common key feature to all cellular organisms. In concordance with these observations, the cell can be considered a complex metabolic network which mainly integrates a large ensemble of self-organized multienzymatic complexes interconnected by substrate fluxes and regulatory signals, where multiple autonomous oscillatory and quasi-stationary catalytic patterns simultaneously emerge. The network adjusts the internal metabolic activities to the external change by means of flux plasticity and structural plasticity. Methodology/Principal Findings In order to research the systemic mechanisms involved in the regulation of the cellular enzymatic activity we have studied different catalytic activities of a dissipative metabolic network under different external stimuli. The emergent biochemical data have been analysed using statistical mechanic tools, studying some macroscopic properties such as the global information and the energy of the system. We have also obtained an equivalent Hopfield network using a Boltzmann machine. Our main result shows that the dissipative metabolic network can behave as an attractor metabolic network. Conclusions/Significance We have found that the systemic enzymatic activities are governed by attractors with capacity to store functional metabolic patterns which can be correctly recovered from specific input stimuli. The network attractors regulate the catalytic patterns, modify the efficiency in the connection between the multienzymatic complexes, and stably retain these modifications. Here for the first time, we have introduced the general concept of attractor metabolic network, in which this dynamic behavior is observed.

De la Fuente, Ildefonso M.; Cortes, Jesus M.; Pelta, David A.; Veguillas, Juan

2013-01-01

337

Inferring general relations between network characteristics from specific network ensembles.  

PubMed

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. PMID:22701586

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

2012-01-01

338

BES Science Network Requirements  

SciTech Connect

The Energy Sciences Network (ESnet) is the primary provider of network connectivityfor the US Department of Energy Office of Science (SC), the single largest supporter of basic research in the physical sciences in the United States. In support of the Office ofScience programs, ESnet regularly updates and refreshes its understanding of the networking requirements of the instruments, facilities, scientists, and science programs that it serves. This focus has helped ESnet to be a highly successful enabler of scientific discovery for over 20 years.

Dart, Eli; Tierney, Brian; Dart, Eli; Biocca, A.; Carlson, R.; Chen, J.; Cotter, S.; Dattoria, V.; Davenport, J.; Gaenko, A.; Kent, P.; Lamm, M.; Miller, S.; Mundy, C.; Ndousse, T.; Pederson, M.; Perazzo, A.; Popescu, R.; Rouson, D.; Sekine, Y.; Sumpter, B.; Wang, C.-Z.; Whitelam, S.; Zurawski, J.

2011-02-01

339

The Gay Financial Network  

NSDL National Science Digital Library

In his mission statement, Walter B. Schubert, CEO and president of the Gay Financial Network (GFN), explains the driving force behind GFN's creation: "To build the first all encompassing financial services Web site to empower the American gay and lesbian community..." The Gay Financial Network is a financial news portal that targets the gay community. The articles are divided into several "channels" including Gay Financial News, Financial Planning, Home and Office, and Women's Channel. Financial services include information on online trading, banking, mortgages, and annuities. GFN also provides professional tools such as a gay and gay-friendly professionals directory and articles and information for career networking.

340

Local area gigabit networking  

SciTech Connect

Computer networks must become faster as the equipment that is being interconnected increases in power and performance. Ethemet, with a 10 Mbit/s speed, seemed awesome a few years ago, but is beginning to show its age as more machines are tied together, and workstations attain the power of yesterdays mainframes. Networks using gigabit speeds are just starting to become available and offer a whole new set of problems and potential. This paper addresses what the higher speeds are being used for, the ''standards'' efforts specifying the higher speed channels, the network architectures being proposed, and some of the open problems requiring extensive further work. 13 refs., 2 figs.

Tolmie, D.E.

1991-01-01

341

A new neural network - intelligence increasing neural network  

Microsoft Academic Search

This paper presents a new architecture of neural networks - intelligence increasing neural network (IINN). Formed surrounding the center of knowledge system, this neural network achieves the building, memory and use of the data base with clear structure. It obtains good classification results with more clear-cut meaning than other neural networks', using a discrimination principle based on Bayesian maximum posterior

Ni Zheng; Su Guang-da; Wang Jun-yan

2003-01-01

342

Rule Extraction: Using Neural Networks or for Neural Networks?  

Microsoft Academic Search

In the research of rule extraction from neural networks, fidelity describes how well the rules mimic the behavior of a neural network while accuracy describes how well the rules can be generalized. This paper identifies the fidelity-accuracy dilemma. It argues to distinguish rule extraction using neural networks and rule extraction for neural networks according to their differing goals, where fidelity

Zhi-hua Zhou

2004-01-01

343

NETWORK DRIVER FOR COMMUNICATION IN SPV INDUSTRIAL NETWORK  

Microsoft Academic Search

In the present paper the development of a network driver for communication in SPV industrial controllers has been discussed. The hardware\\/software approach for realisation of the network driver is offered. The network driver realises all functions of sending and receiving, protecting times in industrial network, the repeating of the message when an error occurs and the solving of the conflict

Georgy Slavchev Mihov; Stanimir Damyanov Mollov; Ratcho Marinov Ivanov; Stoyan Nikolov Jilov

344

Inferring Network Mechanisms: The Drosophila melanogaster Protein Interaction Network  

Microsoft Academic Search

Naturally occurring networks exhibit quantitative features revealing underly- ing growth mechanisms. Numerous network mechanisms have recently been proposed to reproduce specific properties such as degree distributions or clus- tering coefficients. We present a method for inferring the mechanism most accurately capturing a given network topology, exploiting discriminative tools from machine learning. The Drosophila melanogaster protein network is con- fidently and

Manuel Middendorf; Etay Ziv; Chris Wiggins

345

Joint network and channel coding for cooperative networks  

Microsoft Academic Search

In this paper we propose joint network and channel coding schemes for cooperative networks. The joint decoding schemes require no adjustment to either the sending or intermediary network nodes, but are achieved by describing joint network code \\/ channel code Tanner graphs at the receiving node and applying iterative sum-product decoding. The performance of the proposed schemes are simulated on

Sarah J. Johnson; Christopher M. Kellett

2007-01-01

346

Performance Evaluation of a Mobile Agent Network Using Network Calculus  

Microsoft Academic Search

This paper deals with performance evaluation of a mobile agent network using network calculus. A mobile agent network includes\\u000a a multi-agent system and a set of processing nodes connected by a communication network where agents reside and operate as\\u000a a team. We describe such a network as a queuing system where an agent represents an information unit to be served,

Vjekoslav Sinkovic; Mario Kusek; Gordan Jezic; Ignac Lovrek

2008-01-01

347

Multitasking associative networks.  

PubMed

We introduce a bipartite, diluted and frustrated, network as a sparse restricted Boltzmann machine and we show its thermodynamical equivalence to an associative working memory able to retrieve several patterns in parallel without falling into spurious states typical of classical neural networks. We focus on systems processing in parallel a finite (up to logarithmic growth in the volume) amount of patterns, mirroring the low-level storage of standard Amit-Gutfreund-Sompolinsky theory. Results obtained through statistical mechanics, the signal-to-noise technique, and Monte Carlo simulations are overall in perfect agreement and carry interesting biological insights. Indeed, these associative networks pave new perspectives in the understanding of multitasking features expressed by complex systems, e.g., neural and immune networks. PMID:23368622

Agliari, Elena; Barra, Adriano; Galluzzi, Andrea; Guerra, Francesco; Moauro, Francesco

2012-12-28

348

Multitasking Associative Networks  

NASA Astrophysics Data System (ADS)

We introduce a bipartite, diluted and frustrated, network as a sparse restricted Boltzmann machine and we show its thermodynamical equivalence to an associative working memory able to retrieve several patterns in parallel without falling into spurious states typical of classical neural networks. We focus on systems processing in parallel a finite (up to logarithmic growth in the volume) amount of patterns, mirroring the low-level storage of standard Amit-Gutfreund-Sompolinsky theory. Results obtained through statistical mechanics, the signal-to-noise technique, and Monte Carlo simulations are overall in perfect agreement and carry interesting biological insights. Indeed, these associative networks pave new perspectives in the understanding of multitasking features expressed by complex systems, e.g., neural and immune networks.

Agliari, Elena; Barra, Adriano; Galluzzi, Andrea; Guerra, Francesco; Moauro, Francesco

2012-12-01

349

Patent Citation Networks  

NASA Astrophysics Data System (ADS)

Patent applications contain citations which are similar to but different from those found in published scientific papers. In particular, patent citations are governed by legal rules. Moreover, a large fraction of citations are made not by the patent inventor, but by a patent examiner during the application procedure. Using a patent database, which contains the patent citations, assignees and inventors, we have applied network analysis and built network models. Our work includes determining the structure of the patent citation network and comparing it to existing results for scientific citation networks; identifying differences between various technological fields and comparing the observed differences to expectations based on anecdotal evidence about patenting practice; and developing models to explain the results.

Strandburg, Katherine; Tobochnik, Jan; Csardi, Gabor

2005-03-01

350

Network Engineering Assessment Facility.  

National Technical Information Service (NTIS)

We are providing this report for your information and use. The audit was performed in response to your request for assistance in reviewing the operations of the Defense Information Systems Agency (DISA) Network Engineering Assessment Facility (NEAF), a su...

1996-01-01

351

Pelvic Floor Disorders Network  

MedlinePLUS

... studies are shown in the box to the right. Click the link to find out more about ... Network, please contact: Dennis Wallace Principal Investigator RTI International 3040 Cornwallis Road, Cox 239 Research Triangle Park, ...

352

The MAD Scientist Network  

NSDL National Science Digital Library

The Mad Scientist Network, provided by Washington University at St. Louis Medical School, is a Web based "ask a scientist" forum. You ask a question, and a scientist answers it. Answers are usually concise. The expert scientists include high school teachers, university faculty, and others. Both questions and answers are submitted via Web forms. A browsable and searchable question and answer archive is maintained. Scientists interested in joining the Mad Scientist Network will find information at the site. The Mad Scientist Network is part of the St. Louis Science Education Network. http://medinfo.wustl.edu/~ysp/MSN/ Scientists interested in participating: http://medicine.wustl.edu/~ysp/MSN/join/ List of "Mad Scientists": http://medicine.wustl.edu/cgi/cgiwrap.cgi/~ysp/mad/mad.scilist

1997-01-01

353

Interception in a Network.  

National Technical Information Service (NTIS)

The paper presents an algorithm for determining where to place intercepting units in order to maximize the probability of preventing an opposing force from proceeding from one particular node in an undirected network to another. The usual gaming assumptio...

R. D. Wollmer

1970-01-01

354

Network User Information Support.  

National Technical Information Service (NTIS)

With increasing interest in the development of computer networks and the proliferation of remote entry capability from user terminals, user support takes on new dimensions. Some user characteristics are outlined as they affect user support. User support r...

A. J. Neumann

1973-01-01

355

Network alarm assessment.  

National Technical Information Service (NTIS)

Physical intrusion alarm systems provide a structural and operating model that gives useful insights into how to detect intrusions into computer networks. This paper covers one major component of an alarm system called the assessment subsystem. Assessment...

D. J. Bailey

1994-01-01

356

The Deep Space Network.  

National Technical Information Service (NTIS)

Work accomplished on the Deep Space Network (DSN) was described, including the following topics: supporting research and technology, advanced development and engineering, system implementation, and DSN operations pertaining to mission-independent or multi...

1975-01-01

357

Hormone Health Network  

MedlinePLUS

... Search New From the Network Subscribe Fact Sheet Diets that Work Feb 2014 Women Men Patient Guide Diabetes and Pregancy Jan 2014 Women Patient Guide Polycystic Ovary Syndrome Jan 2014 Women Fact Sheet Hypothyroidism and Heart ...

358

Evolution of document networks  

PubMed Central

How does a network of documents grow without centralized control? This question is becoming crucial as we try to explain the emergent scale-free topology of the World Wide Web and use link analysis to identify important information resources. Existing models of growing information networks have focused on the structure of links but neglected the content of nodes. Here I show that the current models fail to reproduce a critical characteristic of information networks, namely the distribution of textual similarity among linked documents. I propose a more realistic model that generates links by using both popularity and content. This model yields remarkably accurate predictions of both degree and similarity distributions in networks of web pages and scientific literature.

Menczer, Filippo

2004-01-01

359

Evolution of document networks.  

PubMed

How does a network of documents grow without centralized control? This question is becoming crucial as we try to explain the emergent scale-free topology of the World Wide Web and use link analysis to identify important information resources. Existing models of growing information networks have focused on the structure of links but neglected the content of nodes. Here I show that the current models fail to reproduce a critical characteristic of information networks, namely the distribution of textual similarity among linked documents. I propose a more realistic model that generates links by using both popularity and content. This model yields remarkably accurate predictions of both degree and similarity distributions in networks of web pages and scientific literature. PMID:14747653

Menczer, Filippo

2004-04-01

360

Communicating Networked Control Systems.  

National Technical Information Service (NTIS)

This report describes research conducted over a twelve month period under support from a multi-university research grant whose focus is the technological foundations of Communicating Networked Control Systems. Coordinated efforts at four participating ins...

J. Baillieul P. R. Kumar P. S. Krishnaprasad R. W. Brockett

2007-01-01

361

Invariant Scattering Convolution Networks.  

PubMed

A wavelet scattering network computes a translation invariant image representation, which is stable to deformations and preserves high frequency information for classification. It cascades wavelet transform convolutions with non-linear modulus and averaging operators. The first network layer outputs SIFT-type descriptors whereas the next layers provide complementary invariant information which improves classification. The mathematical analysis of wavelet scattering networks explain important properties of deep convolution networks for classification. A scattering representation of stationary processes incorporates higher order moments and can thus discriminate textures having same Fourier power spectrum. State of the art classification results are obtained for handwritten digits and texture discrimination, with a Gaussian kernel SVM and a generative PCA classifier. PMID:23070037

Bruna, Joan; Mallat, Stephane

2012-10-12

362

Invariant scattering convolution networks.  

PubMed

A wavelet scattering network computes a translation invariant image representation which is stable to deformations and preserves high-frequency information for classification. It cascades wavelet transform convolutions with nonlinear modulus and averaging operators. The first network layer outputs SIFT-type descriptors, whereas the next layers provide complementary invariant information that improves classification. The mathematical analysis of wavelet scattering networks explains important properties of deep convolution networks for classification. A scattering representation of stationary processes incorporates higher order moments and can thus discriminate textures having the same Fourier power spectrum. State-of-the-art classification results are obtained for handwritten digits and texture discrimination, with a Gaussian kernel SVM and a generative PCA classifier. PMID:23787341

Bruna, Joan; Mallat, Stéphane

2013-08-01

363

International Cancer Screening Network  

Cancer.gov

Skip to Main Content Search International Cancer Screening Network Sponsored by the National Cancer Institute Working Together to Evaluate Cancer Screening and Improve Outcomes Internationally About the ICSN Overview Participating Countries Contact

364

Ancianos Network Project.  

National Technical Information Service (NTIS)

The objectives of this project include: (a) researching, analyzing, and developing analysis focusing on the 'continuum of care' as it affects Hispanic elderly; (b) establishing a national network of at least 65 Hispanic community-based groups to serve low...

C. Lopez E. G. McKay

1992-01-01

365

Network Management Research.  

National Technical Information Service (NTIS)

In our research in distributed data processing systems, we have developed design principles, algorithm concepts, feasibility criteria, and quantitative trade-offs that can be used in the creation of network management functions. In particular, we concentr...

C. V. Ramamoorthy

1980-01-01

366

Railway network in China  

NASA Astrophysics Data System (ADS)

Railway plays a very important role in the transportation of middle-developing countries. All the railway lines organize a network. The railway stations can be defined as the nodes, and the railway lines as edges. We have collected data as many as possible about the network in China from 1900 to 2002. Also we have made a statistical investigation on the data and have obtained some statistical properties, such as vertex degree distribution, averaged vertex degree, clustering coefficient and averaged path length. The results show that the network is not a scaling-free one. To explain the results, we present a self-adaptive model for describing the development process of this network and searching the mechanism of its evolution. The simulation results based on the model show a very good agreement with statistical data.

Hu, Juan; Zhang, Peipei; Qiu, Rong; Tang, Jiying; He, Da-Ren

2004-03-01

367

Interconnecting District Heating Networks.  

National Technical Information Service (NTIS)

The National Energy Administration has, on behalf of the Swedish Government, investigated the potential for interconnecting district heating networks in Sweden. The purpose is twofold: by creating a large heat load, cheap energy sources like waste heat ca...

1985-01-01

368

Neural Network Development Tool (NETS)  

NASA Technical Reports Server (NTRS)

Artificial neural networks formed from hundreds or thousands of simulated neurons, connected in manner similar to that in human brain. Such network models learning behavior. Using NETS involves translating problem to be solved into input/output pairs, designing network configuration, and training network. Written in C.

Baffes, Paul T.

1990-01-01

369

Securing Mobile Ad Hoc Networks  

Microsoft Academic Search

The vision of nomadic computing with its ubiquitous access has stimulated much interest in the Mobile Ad Hoc Networking (MANET) technology. Those infrastructure- less, self-organized networks that either operate autonomously or as an extension to the wired networking infrastructure, are expected to support new MANET-based applications. However, the proliferation of this networking paradigm is strongly dependent on the availability of

Panagiotis Papadimitratos; Zygmunt J. Haas

2003-01-01

370

Proofs of Networks of Processes  

Microsoft Academic Search

We present a proof method for networks of processes in which component processes communicate exclusively through messages. We show how to construct proofs of invariant properties which hold at all times during network computation, and terminal properties which hold upon termination of network computation, if network computation terminates. The proof method is based upon specifying a process by a pair

Jayadev Misra; K. Mani Chandy

1981-01-01

371

Analysis of Nonlinear Irregular Networks.  

National Technical Information Service (NTIS)

The characterization of a broad class of nonlinear networks, defined in terms of the type of network elements admitted in the class, is investigated. For the defined class of networks, criteria are established for the characterizability of a network in th...

S. J. Oh

1966-01-01

372

Theory of Interacting Neural Networks  

Microsoft Academic Search

In this contribution we give an overview over recent work on the theory of interacting neural networks. The model is defined in Section 2. The typical teacher\\/student scenario is considered in Section 3. A static teacher network is presenting training examples for an adaptive student network. In the case of multilayer networks, the student shows a transition from a symmetric

Wolfgang Kinzel

2002-01-01

373

NETMATE: A network management environment  

Microsoft Academic Search

A description is given of the Network Management Analysis and Testing Environment (NETMATE) project, the prime goal of which is to develop a unified and comprehensive software environment for network management to oversee and orchestrate the operations of diverse devices and protocols in large, heterogeneous computer networks. The overall NETMATE architecture is discussed, and the network management functions performed by

A. Dupay; Soumitra Sengupta; Ouri Wolfson; Yechiam Yemini

1991-01-01

374

Security issues in SCADA networks  

Microsoft Academic Search

The increasing interconnectivity of SCADA (Supervisory Control and Data Acquisition) networks has exposed them to a wide range of network security problems. This paper provides an overview of all the crucial research issues that are involved in strengthening the cyber security of SCADA networks. The paper describes the general architecture of SCADA networks and the properties of some of the

Vinay M. Igure; Sean A. Laughter; Ronald D. Williams

2006-01-01

375

Survivability strategies for broadband networks  

Microsoft Academic Search

The survivability of telecommunications networks is of increasing importance as companies and individuals become more dependent on access to a range of communications services. The challenge for network operators is to design a cost-effective network to meet a range of survivability demands. This paper first examines the broad decisions involved in selecting a survivability strategy, such as which network layers

David Johnson

1996-01-01

376

Reconfigurable nodes for future networks  

Microsoft Academic Search

Future network architectures aim at solving the shortcomings of the traditional, static Internet architecture. In order to provide optimal service they have to adapt their functionality to different networking situations. This can be achieved by dividing the networking functionality into modular blocks and combining them as required at runtime. While the feasibility and flexibility of novel network architectures have been

Ariane Keller; Bernhard Plattner; Enno Lübbers; Marco Platzner; Christian Plessl

2010-01-01

377

Network Security and Safety Precautions  

Microsoft Academic Search

A more and more enterprises using Web services to accelerate its own development. At this point, how to network in an open application environment, guard the confidentiality of their data, resources are more and more concern for people, network security has become the network an integral part of the building. This paper introduces the architecture of network security, and further

Yishan Gong; Guanghong Yue; Quansheng Xu

2010-01-01

378

Networking Goes International: An Update  

Microsoft Academic Search

This literature review asks three questions of the scholarship on the regulatory networks that have so transformed global governance. First, what are these networks good for? We summarize the state of the literature on regulatory races, the fit between networks and the process of globalization, and the crucial role of the revolution in communications in the development of networks, introducing

Anne-Marie Slaughter; David Zaring

2006-01-01

379

Complex networks theory for analyzing metabolic networks  

Microsoft Academic Search

One of the main tasks of post-genomic informatics is to systematically investigate all molecules and their interactions within\\u000a a living cell so as to understand how these molecules and the interactions between them relate to the function of the organism,\\u000a while networks are appropriate abstract description of all kinds of interactions. In the past few years, great achievement\\u000a has been

Jing Zhao; Hong Yu; Jianhua Luo; Z. W. Cao; Yi-Xue Li

2006-01-01

380

Artificial neural networks  

SciTech Connect

This volume provides an introduction to the exciting field of artificial neural networks and their potential role in the emerging field of neurocomputing. Although the genesis of this subject can be traced back to the 1940s, the present interest is largely due to the recent developments in theoretical models, technologies, and algorithms. This volume is devoted to introductory and theoretical concepts, and the emphasis is on network architectures, learning, associative memories, with a glimpse of the application areas and implementation experiences.

Vemuri, V.

1988-01-01

381

Wireless Multimedia Sensor Networks  

Microsoft Academic Search

\\u000a The emergence of low-cost and mature technologies in wireless communication, visual sensor devices, and digital signal processing\\u000a facilitate of wireless multimedia sensor networks (WMSN). Like sensor networks which respond to sensory information such as\\u000a temperature and humidity, WMSN interconnects autonomous devices for capturing and processing video and audio sensory information.\\u000a This survey highlights the following topics (1) a summary of

Ivan Lee; William Shaw; Xiaoming Fan

382

Global Telescope Network Website  

NSDL National Science Digital Library

This Web site contains information for both partners (those with their own telescopes) and associates (those who wish to use a network telescope.) The purpose of the Global Telescope Network (GTN) is to use small telescopes to obtain ground-based observations of high-energy objects of interest to Swift, GLAST (renamed Fermi in 2008) and XMM-Newton missions. It is used both by formal educators working with students and by amateur astronomers.

2005-06-14

383

VOIP over Space Networks  

NASA Technical Reports Server (NTRS)

This viewgraph presentation reviews Voice over Internet Protocol (VOIP) over a space networking environment. The topics include: 1) Drivers for VOIP in Space; 2) Challenges in the Space Networking Environment: Long Latencies, Path errors, Simplex paths, Asymmetric paths, QoS requirements, Team-based operations, and Overhead concerns; 3) Possible VOIPOSN approaches; 4) Study of BER, code type and voice frame length on PESQ-MOS; 5) Codec Latency Trade Space; and 6) Testbed.

Okino, C.; Kwong, W.; Pang, Jackson; Gao, Jerry; Clare, L.

2006-01-01

384

Global Oscillation Network Group  

NASA Astrophysics Data System (ADS)

The Global Oscillation Network Group (GONG) is an international, community-based project, operated by the NATIONAL SOLAR OBSERVATORY for the US National Science Foundation, to conduct a detailed study of the internal structure and dynamics of the Sun over an 11 year solar cycle using helioseismology. 10 242 velocity images are obtained by a six-station network located at Big Bear Solar Observato...

Murdin, P.

2000-11-01

385

Prestressed surgical network  

US Patent & Trademark Office Database

The invention relates to a surgical support or network for anchoring endoprostheses and/or reinforcing the bone cement used for anchoring endoprostheses. The support or network is designed as a prestressable prosthesis quiver (1) made of one or more layers of threads so that when prestressed, for example by means of a bone dowel (2) and a titanium cap (6), it can be anchored in the bony bed.

1996-01-02

386

Intelligence in optical networks  

Microsoft Academic Search

Optical networks need added intelligence and performance at the edge to efficiently link broadband access infrastructure to the optical multi-provider transport environment. Intelligent edge ruting platforms deliver carrier-class performance and reliability essential to the delivery of next-generation services requiring end-to-end QoS, diversified levels of security and users' network self-configuration. This digest paper is basing mainly on special issue of IEEE

Ryszard S. Romaniuk

2003-01-01

387

Characterizing residential broadband networks  

Microsoft Academic Search

A large and rapidly growing proportion of users connect to the Internet via residential broadband networks such as Dig- ital Subscriber Lines (DSL) and cable. Residential networks are often the bottleneck in the last mile of today's Internet. Their characteristics critically affect Internet applications, including voice-over-IP, online games, and peer-to-peer con- tent sharing\\/delivery systems. However, to date, few studies have

Marcel Dischinger; Andreas Haeberlen; P. Krishna Gummadi; Stefan Saroiu

2007-01-01

388

Leaf Pack Network  

NSDL National Science Digital Library

The Leaf Pack Network (LPN) is a network of teachers and students investigating their local stream ecosystems by participating in the leaf pack experiment, which involves creating an artificial leaf pack (dry leaves in a mesh bag), immersing it in a stream for 3-4 weeks, and examining it for signs of aquatic insects as indicators of stream health. Participating classrooms share their data through the internet. This activity highlights the connection between streamside forests and the ecology of rivers and streams.

389

Flexible and robust networks.  

PubMed

We consider networks with two types of nodes. The v-nodes, called centers, are hyperconnected and interact with one another via many u-nodes, called satellites. This centralized architecture, widespread in gene networks, possesses two fundamental properties. Namely, this organization creates feedback loops that are capable of generating practically any prescribed patterning dynamics, chaotic or periodic, or having a number of equilibrium states. Moreover, this organization is robust with respect to random perturbations of the system. PMID:22809346

Vakulenko, Sergey A; Radulescu, Ovidiu

2012-04-01

390

Evolution of networks  

Microsoft Academic Search

We review the recent fast progress in statistical physics of evolving\\u000anetworks. Interest has focused mainly on the structural properties of random\\u000acomplex networks in communications, biology, social sciences and economics. A\\u000anumber of giant artificial networks of such a kind came into existence\\u000arecently. This opens a wide field for the study of their topology, evolution,\\u000aand complex processes

S. N. Dorogovtsev; J. F. F. Mendes

2002-01-01

391

Bolivian Seismic Network  

NASA Astrophysics Data System (ADS)

One of the biggest challenges into the Seismic Network of Bolivia, composed of seven stations, is to connect all the differents characteristic of them. The Observatory San Calixto, network operator, is one of the few private seismic observatories in the world and for this reason is working only with agreement support or extern cooperation. This problem needs a promptly solution to obtain data system more convenient, in a real time, more effective and compatible with a future extension network. Now, we have differences in the equipment and transmission too. Two of our network stations, are part of the IMS (International System of Data), the information are transmitted by telemetry way from Primary Station PS6 (LPAZ) to OSC, and then by Vsat to IMS and by optic fiber to AFTAC. The auxiliary seismic station AS08 (SIV) sends information to DASE France by satellite way, and then DASE transmits to the IMS, and to the OSC by Internet. Similar situation is used for another station: MOC. The data of the other four stations are transmitted by telemetry to the OSC center, but here the difference with the other stations is that they are working with analogy system. This network does not cover all the Bolivian territory for a completed monitoring of the seismic activity of the country. For this reason it is very important for Bolivia to extend the network with installation of other stations and a project for the characteristic compatibility (formats specially) of this news stations with the actual stations and temporally stations. Temporally stations are mainly used to support the network and to obtain the evaluation of micro activity in some areas that have a possible seismic threat and because of the actual network distribution where the activity is unknown for us.

Minaya, E.; Rougon, P.; Valero, D.; Fernandez, G.; Lazaro, E.; Cano, W.

2007-05-01

392

Network vulnerability assessment using Bayesian networks  

NASA Astrophysics Data System (ADS)

While computer vulnerabilities have been continually reported in laundry-list format by most commercial scanners, a comprehensive network vulnerability assessment has been an increasing challenge to security analysts. Researchers have proposed a variety of methods to build attack trees with chains of exploits, based on which post-graph vulnerability analysis can be performed. The most recent approaches attempt to build attack trees by enumerating all potential attack paths, which are space consuming and result in poor scalability. This paper presents an approach to use Bayesian network to model potential attack paths. We call such graph as "Bayesian attack graph". It provides a more compact representation of attack paths than conventional methods. Bayesian inference methods can be conveniently used for probabilistic analysis. In particular, we use the Bucket Elimination algorithm for belief updating, and we use Maximum Probability Explanation algorithm to compute an optimal subset of attack paths relative to prior knowledge on attackers and attack mechanisms. We tested our model on an experimental network. Test results demonstrate the effectiveness of our approach.

Liu, Yu; Man, Hong

2005-03-01

393

Program Helps Simulate Neural Networks  

NASA Technical Reports Server (NTRS)

Neural Network Environment on Transputer System (NNETS) computer program provides users high degree of flexibility in creating and manipulating wide variety of neural-network topologies at processing speeds not found in conventional computing environments. Supports back-propagation and back-propagation-related algorithms. Back-propagation algorithm used is implementation of Rumelhart's generalized delta rule. NNETS developed on INMOS Transputer(R). Predefines back-propagation network, Jordan network, and reinforcement network to assist users in learning and defining own networks. Also enables users to configure other neural-network paradigms from NNETS basic architecture. Small portion of software written in OCCAM(R) language.

Villarreal, James; Mcintire, Gary

1993-01-01

394

Network Probe 0.5  

NSDL National Science Digital Library

Network Probe 0.5 is a free network monitor and protocol analyzer that offers users an immediate picture of the current traffic situation on their network. Network Probe 0.5 also gives users the option to identify and isolate traffic problems and congestion throughout their entire network. Adding breadth and depth to the available features is the fact that users may also filter out selected protocols and hosts, along with sorting out network traffic by the amount of bytes sent or received. Network Probe 0.5 is compatible with all systems running Windows NT and higher.

395

Scaling in Transportation Networks  

PubMed Central

Subway systems span most large cities, and railway networks most countries in the world. These networks are fundamental in the development of countries and their cities, and it is therefore crucial to understand their formation and evolution. However, if the topological properties of these networks are fairly well understood, how they relate to population and socio-economical properties remains an open question. We propose here a general coarse-grained approach, based on a cost-benefit analysis that accounts for the scaling properties of the main quantities characterizing these systems (the number of stations, the total length, and the ridership) with the substrate's population, area and wealth. More precisely, we show that the length, number of stations and ridership of subways and rail networks can be estimated knowing the area, population and wealth of the underlying region. These predictions are in good agreement with data gathered for about subway systems and more than railway networks in the world. We also show that train networks and subway systems can be described within the same framework, but with a fundamental difference: while the interstation distance seems to be constant and determined by the typical walking distance for subways, the interstation distance for railways scales with the number of stations.

Louf, Remi; Roth, Camille; Barthelemy, Marc

2014-01-01

396

Network basics for telemedicine.  

PubMed

Early telemedicine networks employed dedicated telecommunications circuits (e.g. leased digital lines) in which the sender and receiver were connected by a private circuit. More recently, the Internet has become widely available for general use, including telemedicine. The Internet was engineered to permit network paths to be shared by all users, so data transmission is fundamentally different from traditional, circuit-switched networks. Early telemedicine applications demonstrated the feasibility of Internet Protocol transmission. The basic performance criteria to use in evaluating newer digital communications technologies that carry both voice and data are: (1) bandwidth; (2) packet loss; (3) end-to-end delay; (4) jitter; (5) privacy and security. Network engineering involves performance trade-offs between the hardware, architecture, security and the budget available. A telemedicine application may be running over a network whose design is entirely under the user's control, or the application may employ some part of the Internet whose design is unknown to the user. If an application is not running to satisfaction, then a network engineer should be consulted. PMID:15829050

Gemmill, Jill

2005-01-01

397

Stochastic pooling networks  

NASA Astrophysics Data System (ADS)

We introduce and define the concept of a stochastic pooling network (SPN), as a model for sensor systems where redundancy and two forms of 'noise'—lossy compression and randomness—interact in surprising ways. Our approach to analysing SPNs is information theoretic. We define an SPN as a network with multiple nodes that each produce noisy and compressed measurements of the same information. An SPN must combine all these measurements into a single further compressed network output, in a way dictated solely by naturally occurring physical properties—i.e. pooling—and yet cause no (or negligible) reduction in mutual information. This means that SPNs exhibit redundancy reduction as an emergent property of pooling. The SPN concept is applicable to examples in biological neural coding, nanoelectronics, distributed sensor networks, digital beamforming arrays, image processing, multiaccess communication networks and social networks. In most cases the randomness is assumed to be unavoidably present rather than deliberately introduced. We illustrate the central properties of SPNs for several case studies, where pooling occurs by summation, including nodes that are noisy scalar quantizers, and nodes with conditionally Poisson statistics. Other emergent properties of SPNs and some unsolved problems are also briefly discussed.

McDonnell, Mark D.; Amblard, Pierre-Olivier; Stocks, Nigel G.

2009-01-01

398

Controllability of Complex Networks  

NASA Astrophysics Data System (ADS)

The ultimate proof of our understanding of natural or technological systems is reflected in our ability to control them. While control theory offers mathematical tools to steer engineered systems towards a desired state, we lack a general framework to control complex self-organized systems, like the regulatory network of a cell or the Internet. Here we develop analytical tools to study the controllability of an arbitrary complex directed network, identifying the set of driver nodes whose time-dependent control can guide the system's dynamics. We apply these tools to real and model networks, finding that sparse inhomogeneous networks, which emerge in many real complex systems, are the most difficult to control. In contrast, dense and homogeneous networks can be controlled via a few driver nodes. Counterintuitively, we find that in both model and real systems the driver nodes tend to avoid the hubs. We show that the robustness of control to link failure is determined by a core percolation problem, helping us understand why many complex systems are relatively insensitive to link deletion. The developed approach offers a framework to address the controllability of an arbitrary network, representing a key step towards the eventual control of complex systems.

Liu, Yang; Slotine, Jean-Jacques; Barabasi, Albert-Laszlo

2011-03-01

399

Scaling in transportation networks.  

PubMed

Subway systems span most large cities, and railway networks most countries in the world. These networks are fundamental in the development of countries and their cities, and it is therefore crucial to understand their formation and evolution. However, if the topological properties of these networks are fairly well understood, how they relate to population and socio-economical properties remains an open question. We propose here a general coarse-grained approach, based on a cost-benefit analysis that accounts for the scaling properties of the main quantities characterizing these systems (the number of stations, the total length, and the ridership) with the substrate's population, area and wealth. More precisely, we show that the length, number of stations and ridership of subways and rail networks can be estimated knowing the area, population and wealth of the underlying region. These predictions are in good agreement with data gathered for about [Formula: see text] subway systems and more than [Formula: see text] railway networks in the world. We also show that train networks and subway systems can be described within the same framework, but with a fundamental difference: while the interstation distance seems to be constant and determined by the typical walking distance for subways, the interstation distance for railways scales with the number of stations. PMID:25029528

Louf, Rémi; Roth, Camille; Barthelemy, Marc

2014-01-01

400

Interactome Networks and Human Disease  

PubMed Central

Complex biological systems and cellular networks may underlie most genotype to phenotype relationships. Here we review basic concepts in network biology, discussing different types of interactome networks and the insights that can come from analyzing them. We elaborate on why interactome networks are important to consider in biology, how they can be mapped and integrated with each other, what global properties are starting to emerge from interactome network models, and how these properties may relate to human disease.

Vidal, Marc; Cusick, Michael E.; Barabasi, Albert-Laszlo

2011-01-01

401

Centrality Metric for Dynamic Networks  

Microsoft Academic Search

Centrality is an important notion in network analysis and is used to measure\\u000athe degree to which network structure contributes to the importance of a node\\u000ain a network. While many different centrality measures exist, most of them\\u000aapply to static networks. Most networks, on the other hand, are dynamic in\\u000anature, evolving over time through the addition or deletion

Kristina Lerman; Rumi Ghosh; Jeon Hyung Kang

2010-01-01

402

A Tutorial on Optical Networks  

Microsoft Academic Search

In this half-day tutorial, we present the current state-of-the- art in optical networks. We begin by discussing the various optical devices used in optical networks. Then, we present wavelength-routed networks, which is currently the dominant architecture for optical networks. We discuss wavelength allocation policies, calculation of call blocking prob- abilities, and network optimization techniques. Subsequently, we focus on the various

George N. Rouskas; Harry G. Perros

2002-01-01

403

Spiking Neural P Systems and Modularization of Complex Networks from Cortical Neural Network to Social Networks  

Microsoft Academic Search

Summary. An idea of modularization of complex networks (from cortial neural net, Internet computer network, to market and social networks) is explained and some its topic motivations are presented. Then some known modularization algorithms and mod- ular architectures (constructions) of complex networks are discussed in the context of possible applications of spiking neural P systems in order to improve these

Adam Obtulowicz

404

Multifractal analysis of complex networks  

NASA Astrophysics Data System (ADS)

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 Dq 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 Dq due to changes in the parameters of the theoretical network models is also discussed.

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

2012-08-01

405

Network Motifs: Simple Building Blocks of Complex Networks  

NASA Astrophysics Data System (ADS)

Complex networks are studied across many fields of science. To uncover their structural design principles, we defined ``network motifs,'' patterns of interconnections occurring in complex networks at numbers that are significantly higher than those in randomized networks. We found such motifs in networks from biochemistry, neurobiology, ecology, and engineering. The motifs shared by ecological food webs were distinct from the motifs shared by the genetic networks of Escherichia coli and Saccharomyces cerevisiae or from those found in the World Wide Web. Similar motifs were found in networks that perform information processing, even though they describe elements as different as biomolecules within a cell and synaptic connections between neurons in Caenorhabditis elegans. Motifs may thus define universal classes of networks. This approach may uncover the basic building blocks of most networks.

Milo, R.; Shen-Orr, S.; Itzkovitz, S.; Kashtan, N.; Chklovskii, D.; Alon, U.

2002-10-01

406

Quantum Network Coding on Networks with Arbitrarily Distributed Hidden Channels  

NASA Astrophysics Data System (ADS)

Although perfect quantum network coding has been proved to be achievable, it is still puzzling whether it is feasible whenever one or more of the channels are replaced by the hidden ones emerging from quantum entanglement. The question is answered in this paper. First, we propose a quantum network coding protocol over a butterfly network with two hidden channels. Second, we investigate a more general situation, where d-level quantum letters are transmitted through the network containing arbitrarily distributed hidden channels, and prove that quantum network coding on such networks is still achievable.

Zhang, Sheng; Li, Jie; Dong, Heng-Jie; Liu, Jin

2013-10-01

407

Institutionalizing College Networks for Student Success.  

ERIC Educational Resources Information Center

Explores concepts of college "networking" in the context of improving student retention and success, including student-to-student networks, faculty-to-faculty networks, faculty-to-student networks, institution-to-student networks, institution-to-faculty/staff networks, and institution-to-local community networks. Considers the need to address…

Calder, William B.; Gordon, William

1999-01-01

408

Management of coalition sensor networks  

NASA Astrophysics Data System (ADS)

The management of sensor networks in coalition settings has been treated in a piecemeal fashion in the current literature without taking a comprehensive look at the complete life cycle of coalition networks, and determining the different aspects of network management that need to be taken into account for the management of sensor networks in those contexts. In this paper, we provide a holistic approach towards managing sensor networks encountered in the context of coalition operations. We describe how the sensor networks in a coalition ought to be managed at various stages of the life cycle, and the different operations that need to be taken into account for managing various aspects of the networks. In particular, we look at the FCAPS model for network management, and assess the applicability of the FCAPS model to the different aspects of sensor network management in a coalition setting.

Verma, Dinesh Chandra; Brown, Theodore; Ortega, Carolyn

2010-04-01

409

Optimal transport on wireless networks  

NASA Astrophysics Data System (ADS)

We present a study of the application of a variant of a recently introduced heuristic algorithm for the optimization of transport routes on complex networks to the problem of finding the optimal routes of communication between nodes on wireless networks. Our algorithm iteratively balances network traffic by minimizing the maximum node betweenness on the network. The variant we consider specifically accounts for the broadcast restrictions imposed by wireless communication by using a different betweenness measure. We compare the performance of our algorithm to three other known algorithms and find that our algorithm achieves the highest transport capacity both for minimum-node-degree geometric networks, which are directed geometric networks that model wireless communication networks, and for configuration model networks that are uncorrelated scale-free networks.

Yu, Y.; Danila, B.; Marsh, J. A.; Bassler, K. E.

2007-08-01

410

Cyclic networks of quantum gates  

SciTech Connect

In this paper initial steps in an analysis of cyclic networks of quantum logic gates will be given. Cyclic networks are those in which the qubit lines are loops. In our investigations of cyclic networks of quantum gates we have studied one- and two-qubit systems plus two-qubit systems connected to another qubit on an acyclic line. The analysis includes classifying networks into groups, the dynamics of the qubits in the cyclic network, and the perturbation effects of an acyclic qubit acting on a cyclic network of quantum gates. This will be followed by a discussion on quantum algorithms and quantum information processing with cyclic networks of quantum gates. An implementation of a cyclic network quantum memory and quantum sensors via cyclic networks will also be discussed.

Cabauy, Peter [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA (United States); Applied Physics Department, University of Michigan, Ann Arbor, Michigan 48109, USA (United States); Benioff, Paul [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA (United States)

2003-09-01

411

Network-Friendly Gossiping  

NASA Astrophysics Data System (ADS)

The emergence of large-scale distributed applications based on many-to-many communication models, e.g., broadcast and decentralized group communication, has an important impact on the underlying layers, notably the Internet routing infrastructure. To make an effective use of network resources, protocols should both limit the stress (amount of messages) on each infrastructure entity like routers and links, and balance as much as possible the load in the network. Most protocols use application-level metrics such as delays to improve efficiency of content dissemination or routing, but the extend to which such application-centric optimizations help reduce and balance the load imposed to the infrastructure is unclear. In this paper, we elaborate on the design of such network-friendly protocols and associated metrics. More specifically, we investigate random-based gossip dissemination. We propose and evaluate different ways of making this representative protocol network-friendly while keeping its desirable properties (robustness and low delays). Simulations of the proposed methods using synthetic and real network topologies convey and compare their abilities to reduce and balance the load while keeping good performance.

Serbu, Sabina; Rivière, Étienne; Felber, Pascal

412

Trees, networks and optimality  

NASA Astrophysics Data System (ADS)

Theoretical and observational material on form and function of natural networks appeared in somewhat disparate contexts from physics to biology is critically reviewed. Moving from the exact result that drainage network configurations minimizing total energy dissipation are stationary solutions of the general equation describing landscape evolution, the properties and the dynamic origin of the scale-invariant structure of river patterns are discussed in relation to optimal selection. It is argued that at least in the fluvial landscape Nature works through imperfect searches for dynamically accessible optimal configurations and that purely random or deterministic constructs are clearly unsuitable to properly describe natural network forms. We also show that optimal networks are spanning loopless configurations only under precise physical requirements that arise under the constraints imposed by continuity. In the case of rivers, every spanning tree proves a local minimum of total energy dissipation. This is stated in a theorem form applicable to generic networks, suggesting that other branching structures occurring in nature (e.g., scale-free and looping) may possibly arise through optimality to different selective pressures. It is thus suggested that one recurrent self- organized mechanism for the dynamic origin of fractal forms is the robust strive for imperfect optimality that it is observed in many natural patterns, chief and foremost hydrologic ones.

Rinaldo, A.

2008-12-01

413

Viscoelastic Properties of Networks  

NASA Astrophysics Data System (ADS)

A network was characterized by its viscoelastic properties. The viscoelastic property indicates the deformations or changes in the shape and in the internal structure during the evolution of a network. The change in the direction of motion was taken as elastic deformation and the change in the vertical direction as viscous deformation. These deformations were related to the change of geometry of internal structure and of shape. Thus it was possible to characterize a network by its storage and loss moduli. The change of the structure of a network during its evolution changes also its entropy. However entropy depends on the number of microstates of an already existing framework. As examples, two different systems (i) New York Stock Exchange and (ii) a melody were studied for their viscoelastic properties. The change of viscous property was compared with the change of different types of entropies such as configurational entropy, crossing entropy, and topological entropy. This last entropy was introduced and explained in the text. It was found out that there is no direct correspondence between the increase of entropy and the increase of viscous property of a network although they sometimes correlate with each other.

Gündüz, Güngör

414

Complex aperture networks  

NASA Astrophysics Data System (ADS)

A complex network approach is proposed for studying the shear behavior of a rough rock joint. Similarities between aperture profiles are established, and a functional complex network-in each shear displacement-is constructed in two directions: parallel and perpendicular to the shear direction. We find that the growth of the clustering coefficient and that of the number of edges are approximately scaled with the development of shear strength and hydraulic conductivity, which could possibly be utilized to estimate and formulate a friction law and the evolution of shear distribution over asperities. Moreover, the frictional interface is mapped in the global-local parameter space of the corresponding functional friction network, showing the evolution path and, eventually, the residual stage. Furthermore, we show that with respect to shear direction, parallel aperture patches are more adaptable to environmental stimuli than perpendicular profiles. We characterize the pure-contact profiles using the same approach. Unlike the first case, the later networks show a growing trend while in the residual stage; a saturation of links is encoded in contact networks.

Ghaffari, H. O.; Sharifzadeh, M.; Young, R. Paul

2013-02-01

415

Applications of Social Network Analysis  

NASA Astrophysics Data System (ADS)

A social network [2] is a description of the social structure between actors, mostly persons, groups or organizations. It indicates the ways in which they are connected with each other by some relationship such as friendship, kinship, finance exchange etc. In a nutshell, when the person uses already known/unknown people to create new contacts, it forms social networking. The social network is not a new concept rather it can be formed when similar people interact with each other directly or indirectly to perform particular task. Examples of social networks include a friendship networks, collaboration networks, co-authorship networks, and co-employees networks which depict the direct interaction among the people. There are also other forms of social networks, such as entertainment networks, business Networks, citation networks, and hyperlink networks, in which interaction among the people is indirect. Generally, social networks operate on many levels, from families up to the level of nations and assists in improving interactive knowledge sharing, interoperability and collaboration.

Thilagam, P. Santhi

416

Neighborhood Environmental Watch Network  

SciTech Connect

The Neighborhood Environmental Watch Network (NEWNET) is a regional network of environmental monitoring stations and a data archival center that supports collaboration between communities, industry, and government agencies to solve environmental problems. The stations provide local displays of measurements for the public and transmit measurements via satellite to a central site for archival and analysis. Station managers are selected from the local community and trained to support the stations. Archived data and analysis tools are available to researchers, educational institutions, industrial collaborators, and the public across the nation through a communications network. Los Alamos National Laboratory and the Environmental Protection Agency have developed a NEWNET pilot program for the Department of Energy. The pilot program supports monitoring stations in Nevada, Arizona, Utah, Wyoming, and California. Additional stations are being placed in Colorado and New Mexico. Pilot stations take radiological and meteorological measurements. Other measurements are possible by exchanging sensors.

Sanders, L.D.

1993-10-01

417

Ramification of stream networks  

PubMed Central

The geometric complexity of stream networks has been a source of fascination for centuries. However, a comprehensive understanding of ramification—the mechanism of branching by which such networks grow—remains elusive. Here we show that streams incised by groundwater seepage branch at a characteristic angle of 2?/5 = 72°. Our theory represents streams as a collection of paths growing and bifurcating in a diffusing field. Our observations of nearly 5,000 bifurcated streams growing in a 100 km2 groundwater field on the Florida Panhandle yield a mean bifurcation angle of 71.9° ± 0.8°. This good accord between theory and observation suggests that the network geometry is determined by the external flow field but not, as classical theories imply, by the flow within the streams themselves.

Devauchelle, Olivier; Petroff, Alexander P.; Seybold, Hansjorg F.; Rothman, Daniel H.

2012-01-01

418

Universality in network dynamics  

NASA Astrophysics Data System (ADS)

Despite significant advances in characterizing the structural properties of complex networks, a mathematical framework that uncovers the universal properties of the interplay between the topology and the dynamics of complex systems continues to elude us. Here we develop a self-consistent theory of dynamical perturbations in complex systems, allowing us to systematically separate the contribution of the network topology and dynamics. The formalism covers a broad range of steady-state dynamical processes and offers testable predictions regarding the system's response to perturbations and the development of correlations. It predicts several distinct universality classes whose characteristics can be derived directly from the continuum equation governing the system's dynamics and which are validated on several canonical network-based dynamical systems, from biochemical dynamics to epidemic spreading. Finally, we collect experimental data pertaining to social and biological systems, demonstrating that we can accurately uncover their universality class even in the absence of an appropriate continuum theory that governs the system's dynamics.

Barzel, Baruch; Barabási, Albert-László

2013-10-01

419

Network topology mapper  

DOEpatents

A method enables the topology of an acyclic fully propagated network to be discovered. A list of switches that comprise the network is formed and the MAC address cache for each one of the switches is determined. For each pair of switches, from the MAC address caches the remaining switches that see the pair of switches are located. For each pair of switches the remaining switches are determined that see one of the pair of switches on a first port and the second one of the pair of switches on a second port. A list of insiders is formed for every pair of switches. It is determined whether the insider for each pair of switches is a graph edge and adjacent ones of the graph edges are determined. A symmetric adjacency matrix is formed from the graph edges to represent the topology of the data link network.

Quist, Daniel A. (Los Alamos, NM); Gavrilov, Eugene M. (Los Alamos, NM); Fisk, Michael E. (Jemez, NM)

2008-01-15

420

The malignant social network  

PubMed Central

Tumors contain a vastly complicated cellular network that relies on local communication to execute malignant programs. The molecular cues that are involved in cell-cell adhesion orchestrate large-scale tumor behaviors such as proliferation and invasion. We have recently begun to appreciate that many tumors contain a high degree of cellular heterogeneity and are organized in a cellular hierarchy, with a cancer stem cell (CSC) population identified at the apex in multiple cancer types. CSCs reside in unique microenvironments or niches that are responsible for directing their behavior through cellular interactions between CSCs and stromal cells, generating a malignant social network. Identifying cell-cell adhesion mechanisms in this network has implications for the basic understanding of tumorigenesis and the development of more effective therapies. In this review, we will discuss our current understanding of cell-cell adhesion mechanisms used by CSCs and how these local interactions have global consequences for tumor biology.

Hale, James S.; Li, Meizhang; Lathia, Justin D.

2012-01-01

421

Prostate Cancer Regulatory Networks  

PubMed Central

Although the timing with which common epithelial malignancies arise and become established remains a matter of debate, it is clear that by the time they are detected these tumors harbor hundreds of deregulated, aberrantly expressed or mutated genes. This enormous complexity poses formidable challenges to identify gene pathways that are drivers of tumorigenesis, potentially suitable for therapeutic intervention. An alternative approach is to consider cancer pathways as interconnected networks, and search for potential nodal proteins capable of connecting multiple signaling networks of tumor maintenance. We have modeled this approach in advanced prostate cancer, a condition with current limited therapeutic options. We propose that the integration of three signaling networks, including chaperone-mediated mitochondrial homeostasis, integrin-dependent cell signaling, and Runx2-regulated gene expression in the metastatic bone microenvironment plays a critical role in prostate cancer maintenance, and offers novel options for molecular therapy.

Altieri, Dario C.; Languino, Lucia R.; Lian, Jane B.; Stein, Janet L.; Leav, Irwin; van Wijnen, Andre J.; Jiang, Zhong; Stein, Gary S.

2010-01-01

422

Weighted network modules  

NASA Astrophysics Data System (ADS)

The inclusion of link weights into the analysis of network properties allows a deeper insight into the (often overlapping) modular structure of real-world webs. We introduce a clustering algorithm clique percolation method with weights (CPMw) for weighted networks based on the concept of percolating k-cliques with high enough intensity. The algorithm allows overlaps between the modules. First, we give detailed analytical and numerical results about the critical point of weighted k-clique percolation on (weighted) Erdos Rényi graphs. Then, for a scientist collaboration web and a stock correlation graph we compute three-link weight correlations and with the CPMw the weighted modules. After reshuffling link weights in both networks and computing the same quantities for the randomized control graphs as well, we show that groups of three or more strong links prefer to cluster together in both original graphs.

Farkas, Illés; Ábel, Dániel; Palla, Gergely; Vicsek, Tamás

2007-06-01

423

Network acceleration techniques  

NASA Technical Reports Server (NTRS)

Splintered offloading techniques with receive batch processing are described for network acceleration. Such techniques offload specific functionality to a NIC while maintaining the bulk of the protocol processing in the host operating system ("OS"). The resulting protocol implementation allows the application to bypass the protocol processing of the received data. Such can be accomplished this by moving data from the NIC directly to the application through direct memory access ("DMA") and batch processing the receive headers in the host OS when the host OS is interrupted to perform other work. Batch processing receive headers allows the data path to be separated from the control path. Unlike operating system bypass, however, the operating system still fully manages the network resource and has relevant feedback about traffic and flows. Embodiments of the present disclosure can therefore address the challenges of networks with extreme bandwidth delay products (BWDP).

Crowley, Patricia (Inventor); Awrach, James Michael (Inventor); Maccabe, Arthur Barney (Inventor)

2012-01-01

424

Stellar Observations Network Group  

NASA Astrophysics Data System (ADS)

SONG is a Danish-led initiative to construct a global network of 1m telescopes devoted to carrying out time-series observations for asteroseismology and to search for extra-solar planets. To pursue these goals the telescopes of the network will be equipped with a high- resolution spectrograph for measuring very precise radial velocities, and with a CCD camera for carrying out photometry of microlensing events observed towards the Galactic Bulge. Currently, funding has been obtained for construction of a full prototype network node. In this contribution we shall describe the current status of the project, and the instrumental setup as well as the software code needed for measuring precise radial velocities through the use of an iodine cell as velocity reference.

Grundahl, F.; Christensen–Dalsgaard, J.; Arentoft, T.; Frandsen, S.; Kjeldsen, H.; Jørgensen, U. G.; Kjaergaard, P.

2008-12-01

425

Neural network technologies  

NASA Technical Reports Server (NTRS)

A whole new arena of computer technologies is now beginning to form. Still in its infancy, neural network technology is a biologically inspired methodology which draws on nature's own cognitive processes. The Software Technology Branch has provided a software tool, Neural Execution and Training System (NETS), to industry, government, and academia to facilitate and expedite the use of this technology. NETS is written in the C programming language and can be executed on a variety of machines. Once a network has been debugged, NETS can produce a C source code which implements the network. This code can then be incorporated into other software systems. Described here are various software projects currently under development with NETS and the anticipated future enhancements to NETS and the technology.

Villarreal, James A.

1991-01-01

426

Analysis of space network loading  

NASA Technical Reports Server (NTRS)

The NASA Space Network (SN) consists of several geosynchronous communications satellites, in addition to ground support facilities. Space Network management must predict years in advance what network resources are necessary to adequately satisfy all SN users. Similarly, users of the Space Network must know throughout all stages of mission planning and operations to what extent their communication support requirements can be met. NASA, at the Goddard Space Flight Center, performs Space Network and Mission Modeling using The Network Planning and Analysis System (NPAS), to determine the answers to these questions.

Simons, Mark; Larrson, Gus

1994-01-01

427

Community Seismic Network (CSN)  

NASA Astrophysics Data System (ADS)

The CSN is a network of low-cost accelerometers deployed in the Pasadena, CA region. It is a prototype network with the goal of demonstrating the importance of dense measurements in determining the rapid lateral variations in ground motion due to earthquakes. The main product of the CSN is a map of peak ground produced within seconds of significant local earthquakes that can be used as a proxy for damage. Examples of this are shown using data from a temporary network in Long Beach, CA. Dense measurements in buildings are also being used to determine the state of health of structures. In addition to fixed sensors, portable sensors such as smart phones are also used in the network. The CSN has necessitated several changes in the standard design of a seismic network. The first is that the data collection and processing is done in the "cloud" (Google cloud in this case) for robustness and the ability to handle large impulsive loads (earthquakes). Second, the database is highly de-normalized (i.e. station locations are part of waveform and event-detection meta data) because of the mobile nature of the sensors. Third, since the sensors are hosted and/or owned by individuals, the privacy of the data is very important. The location of fixed sensors is displayed on maps as sensor counts in block-wide cells, and mobile sensors are shown in a similar way, with the additional requirement to inhibit tracking that at least two must be present in a particular cell before any are shown. The raw waveform data are only released to users outside of the network after a felt earthquake.

Clayton, R. W.; Heaton, T. H.; Kohler, M. D.; Cheng, M.; Guy, R.; Chandy, M.; Krause, A.; Bunn, J.; Olson, M.; Faulkner, M.

2011-12-01

428

Dynamic network management and service integration for airborne network  

NASA Astrophysics Data System (ADS)

The development of airborne network is conducive to resource sharing, flight management and interoperability in civilian and military aviation fields. To enhance the integrated ability of airborne network, the paper focuses on dynamic network management and service integration architecture for airborne network (DNMSIAN). Adaptive routing based on the mapping mechanism between connection identification and routing identification can provide diversified network access, and ensure the credibility and mobility of the aviation information exchange. Dynamic network management based on trustworthy cluster can ensure dynamic airborne network controllable and safe. Service integration based on semantic web and ontology can meet the customized and diversified needs for aviation information services. The DNMSIAN simulation platform demonstrates that our proposed methods can effectively perform dynamic network management and service integration.

Pan, Wei; Li, Weihua

2009-12-01

429

Network Adaptive Deadband: NCS data flow control for shared networks.  

PubMed

This paper proposes a new middleware solution called Network Adaptive Deadband (NAD) for long time operation of Networked Control Systems (NCS) through the Internet or any shared network based on IP technology. The proposed middleware takes into account the network status and the NCS status, to improve the global system performance and to share more effectively the network by several NCS and sensor/actuator data flows. Relationship between network status and NCS status is solved with a TCP-friendly transport flow control protocol and the deadband concept, relating deadband value and transmission throughput. This creates a deadband-based flow control solution. Simulation and experiments in shared networks show that the implemented network adaptive deadband has better performance than an optimal constant deadband solution in the same circumstances. PMID:23208556

Díaz-Cacho, Miguel; Delgado, Emma; Prieto, José A G; López, Joaquín

2012-01-01

430

A Network Primer: Full-Fledged Educational Networks.  

ERIC Educational Resources Information Center

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)

Lehrer, Ariella

1988-01-01

431

Network Adaptive Deadband: NCS Data Flow Control for Shared Networks  

PubMed Central

This paper proposes a new middleware solution called Network Adaptive Deadband (NAD) for long time operation of Networked Control Systems (NCS) through the Internet or any shared network based on IP technology. The proposed middleware takes into account the network status and the NCS status, to improve the global system performance and to share more effectively the network by several NCS and sensor/actuator data flows. Relationship between network status and NCS status is solved with a TCP-friendly transport flow control protocol and the deadband concept, relating deadband value and transmission throughput. This creates a deadband-based flow control solution. Simulation and experiments in shared networks show that the implemented network adaptive deadband has better performance than an optimal constant deadband solution in the same circumstances.

Diaz-Cacho, Miguel; Delgado, Emma; Prieto, Jose A. G.; Lopez, Joaquin

2012-01-01

432

E-Print Network  

NSDL National Science Digital Library

Created by the United States Department of Energy, this website allows users to explore online papers that have been submitted for distribution and review among peers; for publication in journals; or for presentations at conferences. Through the E-print Network, advanced students and scientists can search e-prints on many websites and databases, browse e-prints by subject, and find many scientific societies. Although the network primarily contains physics-related documents, e-prints dealing with other subjects such as chemistry, material sciences, and nuclear sciences are also included.

433

Walks on Weighted Networks  

NASA Astrophysics Data System (ADS)

We investigate the dynamics of random walks on weighted networks. Assuming that the edge weight and the node strength are used as local information by a random walker. Two kinds of walks, weight-dependent walk and strength-dependent walk, are studied. Exact expressions for stationary distribution and average return time are derived and confirmed by computer simulations. The distribution of average return time and the mean-square displacement are calculated for two walks on the Barrat-Barthélemy-Vespignani (BBV) networks. It is found that a weight-dependent walker can arrive at a new territory more easily than a strength-dependent one.

Wu, An-Cai; Xu, Xin-Jian; Wu, Zhi-Xi; Wang, Ying-Hai

2007-02-01

434

Teacher Leaders Network  

NSDL National Science Digital Library

The Teacher Leaders Network (TLN) is an independent, web-based network of experienced, leading, and award-winning teachers who have achieved success as authors, professional developers, trained mentors, policy consultants, and community leaders. This virtual community participates in daily online discussions that explore and debate the merits of educational policies, techniques, and philosophies. Materials available at the TLN web site include weblogs in which members share their experience and insights; links to resources for teacher leadership, coaching and mentoring, education policy, and other topics; links to news articles and publications; and information on the organization's sponsors, funding, and partners.

435

Global Telescope Network Website  

NSDL National Science Digital Library

The Global Telescope Network (GTN) is an informal association of scientists, students, individuals and observatories interested in supporting the NASA Fermi Gamma-ray Space Telescope (formerly GLAST), Swift, and XMM-Newton missions by obtaining and reducing ground-based observations for objects related to the primary science goals for these missions. The GTN website involves students, teachers, and amateur astronomers in cutting-edge astronomical research; contains activities and instructional materials for a range of levels and interests; and provides mentoring in research practices, telescope use, data analysis and educational resources for both partners (those with their own telescopes) and associates (those who wish to use a network telescope).

436

The ribonucleoprotein Csr network.  

PubMed

Ribonucleoprotein complexes are essential regulatory components in bacteria. In this review, we focus on the carbon storage regulator (Csr) network, which is well conserved in the bacterial world. This regulatory network is composed of the CsrA master regulator, its targets and regulators. CsrA binds to mRNA targets and regulates translation either negatively or positively. Binding to small non-coding RNAs controls activity of this protein. Expression of these regulators is tightly regulated at the level of transcription and stability by various global regulators (RNAses, two-component systems, alarmone). We discuss the implications of these complex regulations in bacterial adaptation. PMID:24217225

Seyll, Ethel; Van Melderen, Laurence

2013-01-01

437

The Ribonucleoprotein Csr Network  

PubMed Central

Ribonucleoprotein complexes are essential regulatory components in bacteria. In this review, we focus on the carbon storage regulator (Csr) network, which is well conserved in the bacterial world. This regulatory network is composed of the CsrA master regulator, its targets and regulators. CsrA binds to mRNA targets and regulates translation either negatively or positively. Binding to small non-coding RNAs controls activity of this protein. Expression of these regulators is tightly regulated at the level of transcription and stability by various global regulators (RNAses, two-component systems, alarmone). We discuss the implications of these complex regulations in bacterial adaptation.

Seyll, Ethel; Van Melderen, Laurence

2013-01-01

438

River Network Online  

NSDL National Science Digital Library

The mission of River Network, a non-governmental organization, is "to help people organize to protect and restore rivers and watersheds." To that end, the River Network homepage offers a wealth of information and links on rivers and watersheds including publications, upcoming conferences, watershed protection issues, river conservation job listings, related organizations, and a searchable National Directory of River and Watershed Organizations. The What's New section announces recent publications, events, and ongoing important river/watershed issues. For anyone interested in learning about or participating in River/Watershed initiatives, this is an excellent resource.

1999-01-01

439

Nested neural networks  

NASA Technical Reports Server (NTRS)

Nested neural networks, consisting of small interconnected subnetworks, allow for the storage and retrieval of neural state patterns of different sizes. The subnetworks are naturally categorized by layers of corresponding to spatial frequencies in the pattern field. The storage capacity and the error correction capability of the subnetworks generally increase with the degree of connectivity between layers (the nesting degree). Storage of only few subpatterns in each subnetworks results in a vast storage capacity of patterns and subpatterns in the nested network, maintaining high stability and error correction capability.

Baram, Yoram

1988-01-01

440

Adaptive parallel logic networks  

NASA Technical Reports Server (NTRS)

Adaptive, self-organizing concurrent systems (ASOCS) that combine self-organization with massive parallelism for such applications as adaptive logic devices, robotics, process control, and system malfunction management, are presently discussed. In ASOCS, an adaptive network composed of many simple computing elements operating in combinational and asynchronous fashion is used and problems are specified by presenting if-then rules to the system in the form of Boolean conjunctions. During data processing, which is a different operational phase from adaptation, the network acts as a parallel hardware circuit.

Martinez, Tony R.; Vidal, Jacques J.

1988-01-01

441

ASP Networking Sessions Summary  

NASA Astrophysics Data System (ADS)

In response to evaluation conducted during the Annual Meeting of the Astronomical Society of the Pacific in 2006, ``Engaging the EPO Community: Best Practices, New Approaches,'' loosely structured networking sessions were added by the program committee in an effort to assist conference attendees in achieving their stated conference goals. The co-chairs of the 2007 conference invited registrants to serve as facilitators for twelve networking sessions. This work aims to summarize the conversations that took place during those sessions, based upon notes and artifacts provided to the author by the session facilitators.

Bartolone, L. M.

2008-06-01

442

Synthetic biological networks  

NASA Astrophysics Data System (ADS)

Despite their obvious relationship and overlap, the field of physics is blessed with many insightful laws, while such laws are sadly absent in biology. Here we aim to discuss how the rise of a more recent field known as synthetic biology may allow us to more directly test hypotheses regarding the possible design principles of natural biological networks and systems. In particular, this review focuses on synthetic gene regulatory networks engineered to perform specific functions or exhibit particular dynamic behaviors. Advances in synthetic biology may set the stage to uncover the relationship of potential biological principles to those developed in physics.

Archer, Eric; Süel, Gürol M.

2013-09-01

443

Network management of TCP\\/IP networks: present and future  

Microsoft Academic Search

Recent network management activities in the TCP\\/IP community have focused on standardizing two network management protocols-Simple Network Management Protocol (SNMP) and Common Management Information Services and Protocol Over TCP\\/IP (CMOT)-that provide for the exchange of management information. The current SNMP and CMOT approaches to TCP\\/IP network management are compared from several different perspectives; comparisons are based on both theory and

Amatzia Ben-Artzi; Asheem Chandna; Unni Warrier

1990-01-01

444

Interfacing to a virtualized network infrastructure through network service abstractions  

Microsoft Academic Search

Virtualization is the base for a diversified next-generation network architecture design. Much work has been done on virtualization infrastructure, but it is still unclear how to easily instantiate a network slice that meets a high-level description of network functionality. Our work addresses this problem that occurs at the interface between network service providers and virtualized infrastructure providers. The proposed Service-based

Xin Huang; Shashank Shanbhag; Tilman Wolf

2009-01-01

445

Optimization of directional antenna network topology in Airborne Networks  

Microsoft Academic Search

Future IP-based Airborne Networks, important components in net-centric military communications, are envisioned to consist of a persistent backbone core network and dynamic tactical edge networks. The backbone would consist of quasi-stable platforms equipped with multiple high-capacity directional wireless links. The tactical edge networks would consist of highly dynamic platforms such as fighter jets equipped with omni-directional wireless links, and these

G. Hadynski; S. B. Lee; G. Rajappan; R. Sundaram; X. Wang; F. Zhou

2010-01-01

446

Parsimonious reconstruction of network evolution  

PubMed Central

Background Understanding the evolution of biological networks can provide insight into how their modular structure arises and how they are affected by environmental changes. One approach to studying the evolution of these networks is to reconstruct plausible common ancestors of present-day networks, allowing us to analyze how the topological properties change over time and to posit mechanisms that drive the networks’ evolution. Further, putative ancestral networks can be used to help solve other difficult problems in computational biology, such as network alignment. Results We introduce a combinatorial framework for encoding network histories, and we give a fast procedure that, given a set of gene duplication histories, in practice finds network histories with close to the minimum number of interaction gain or loss events to explain the observed present-day networks. In contrast to previous studies, our method does not require knowing the relative ordering of unrelated duplication events. Results on simulated histories and real biological networks both suggest that common ancestral networks can be accurately reconstructed using this parsimony approach. A software package implementing our method is available under the Apache 2.0 license at http://cbcb.umd.edu/kingsford-group/parana. Conclusions Our parsimony-based approach to ancestral network reconstruction is both efficient and accurate. We show that considering a larger set of potential ancestral interactions by not assuming a relative ordering of unrelated duplication events can lead to improved ancestral network inference.

2012-01-01

447

ASCR Science Network Requirements  

SciTech Connect

The Energy Sciences Network (ESnet) is the primary provider of network connectivity for the US Department of Energy Office of Science, the single largest supporter of basic research in the physical sciences in the United States. In support of the Office of Science programs, ESnet regularly updates and refreshes its understanding of the networking requirements of the instruments, facilities, scientists, and science programs that it serves. This focus has helped ESnet to be a highly successful enabler of scientific discovery for over 20 years. In April 2009 ESnet and the Office of Advanced Scientific Computing Research (ASCR), of the DOE Office of Science, organized a workshop to characterize the networking requirements of the programs funded by ASCR. The ASCR facilities anticipate significant increases in wide area bandwidth utilization, driven largely by the increased capabilities of computational resources and the wide scope of collaboration that is a hallmark of modern science. Many scientists move data sets between facilities for analysis, and in some cases (for example the Earth System Grid and the Open Science Grid), data distribution is an essential component of the use of ASCR facilities by scientists. Due to the projected growth in wide area data transfer needs, the ASCR supercomputer centers all expect to deploy and use 100 Gigabit per second networking technology for wide area connectivity as soon as that deployment is financially feasible. In addition to the network connectivity that ESnet provides, the ESnet Collaboration Services (ECS) are critical to several science communities. ESnet identity and trust services, such as the DOEGrids certificate authority, are widely used both by the supercomputer centers and by collaborations such as Open Science Grid (OSG) and the Earth System Grid (ESG). Ease of use is a key determinant of the scientific utility of network-based services. Therefore, a key enabling aspect for scientists beneficial use of high performance networks is a consistent, widely deployed, well-maintained toolset that is optimized for wide area, high-speed data transfer (e.g. GridFTP) that allows scientists to easily utilize the services and capabilities that the network provides. Network test and measurement is an important part of ensuring that these tools and network services are functioning correctly. One example of a tool in this area is the recently developed perfSONAR, which has already shown its usefulness in fault diagnosis during the recent deployment of high-performance data movers at NERSC and ORNL. On the other hand, it is clear that there is significant work to be done in the area of authentication and access control - there are currently compatibility problems and differing requirements between the authentication systems in use at different facilities, and the policies and mechanisms in use at different facilities are sometimes in conflict. Finally, long-term software maintenance was of concern for many attendees. Scientists rely heavily on a large deployed base of software that does not have secure programmatic funding. Software packages for which this is true include data transfer tools such as GridFTP as well as identity management and other software infrastructure that forms a critical part of the Open Science Grid and the Earth System Grid.

Dart, Eli; Tierney, Brian

2009-08-24

448

Robustness of a partially interdependent network formed of clustered networks  

NASA Astrophysics Data System (ADS)

Clustering, or transitivity, a behavior observed in real-world networks, affects network structure and function. This property has been studied extensively, but most of this research has been limited to clustering in single networks. The effect of clustering on the robustness of coupled networks, on the other hand, has received much less attention. Only the case of a pair of fully coupled networks with clustering has recently received study. Here we generalize the study of clustering of a fully coupled pair of networks and apply it to a partially interdependent network of networks with clustering within the network components. We show, both analytically and numerically, how clustering within networks affects the percolation properties of interdependent networks, including the percolation threshold, the size of the giant component, and the critical coupling point at which the first-order phase transition changes to a second-order phase transition as the coupling between the networks is reduced. We study two types of clustering, one proposed by Newman [Phys. Rev. Lett. 103, 058701 (2009), 10.1103/PhysRevLett.103.058701] in which the average degree is kept constant while the clustering is changed, and the other by Hackett et al. [Phys. Rev. E 83, 056107 (2011), 10.1103/PhysRevE.83.056107] in which the degree distribution is kept constant. The first type of clustering is studied both analytically and numerically, and the second is studied numerically.

Shao, Shuai; Huang, Xuqing; Stanley, H. Eugene; Havlin, Shlomo

2014-03-01

449

Combining Clustering and Bayesian Network for Gene Network Inference  

Microsoft Academic Search

Gene network reconstruction is a multidisciplinary research area involving data mining, machine learning, statistics, ontologies and others. Reconstructed gene network allows us to understand how genes interact with each other. However, network construction is very complex due to highly interactive nature of genes. A proposed approach to solve this complex problem is to cluster the genes according to similarity in

Suhaila Zainudin; Safaai Deris

2008-01-01

450

CROSS-CORRELATION NEURAL NETWORK: A NEW NEURAL NETWORK CLASSIFIER  

Microsoft Academic Search

A neural network is an excellent classifier; however, its performance depends directly on the size and quality of training samples presented to the network. This paper proposes a new neural network approach to deal with the classification problem by applying the concept of cross-correlation to measure the likeness or similarity between the incoming input pattern and the reference patterns of

ARIT THAMMANO; NARODOM KLOMIAM

451

Quantum neural networks (QNNs): inherently fuzzy feedforward neural networks  

Microsoft Academic Search

This paper introduces quantum neural networks (QNNs), a class of feedforward neural networks (FFNNs) inherently capable of estimating the structure of a feature space in the form of fuzzy sets. The hidden units of these networks develop quantized representations of the sample information provided by the training data set in various graded levels of certainty. Unlike other approaches attempting to

Gopathy Purushothaman; Nicolaos B. Karayiannis

1997-01-01

452

Quantum neural networks (QNNs): inherently fuzzy feedforward neural networks  

Microsoft Academic Search

This paper introduces quantum neural networks (QNNs), a class of feedforward neural networks which are inherently capable of estimating the structure of a feature space in the form of fuzzy membership information. The hidden units of these networks develop quantized representations of the crisp sample information provided by the training set in various graded levels of certainty. Experimental results show

Gopathy Purushothaman; Nicolaos B. Karayiannis

1996-01-01

453

A novel fuzzy neural network: the vague neural network  

Microsoft Academic Search

Fuzzy neural network that combines the artificial neural network and fuzzy logic is regarded as one of promising intelligent system. Based on fuzzy theory, fuzzy neural network has its problems: fuzzy membership function is a single value which combines the evidence for and against the pattern without indicating how much there is of which, hence it cannot get the more

Rui Fang; Yibiao Zhao; Wei-sheng Li

2005-01-01

454

Scientific collaboration networks. II. Shortest paths, weighted networks, and centrality  

Microsoft Academic Search

Using computer databases of scientific papers in physics, biomedical research, and computer science, we have constructed networks of collaboration between scientists in each of these disciplines. In these networks two scientists are considered connected if they have coauthored one or more papers together. Here we study a variety of nonlocal statistics for these networks, such as typical distances between scientists

M. E. J. Newman

2001-01-01

455

Promoting Social Network Awareness: A Social Network Monitoring System  

ERIC Educational Resources Information Center

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…

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

2010-01-01

456

Do You Lock Your Network Doors? Some Network Management Precautions.  

ERIC Educational Resources Information Center

Discusses security problems and solutions for networked organizations with Internet connections. Topics include access to private networks from electronic mail information; computer viruses; computer software; corporate espionage; firewalls, that is computers that stand between a local network and the Internet; passwords; and physical security.…

Neray, Phil

1997-01-01

457

Opportunistic networking: data forwarding in disconnected mobile ad hoc networks  

Microsoft Academic Search

Opportunistic networks are one of the most interesting evolutions of MANETs. In opportunistic networks, mobile nodes are enabled to communicate with each other even if a route connecting them never exists. Furthermore, nodes are not supposed to possess or acquire any knowledge about the network topology, which (instead) is necessary in traditional MANET routing protocols. Routes are built dynamically, while

Luciana Pelusi; Andrea Passarella; Marco Conti

2006-01-01

458

NYNEX network exploratorium visualization tool: visualizing telephone network planning  

Microsoft Academic Search

This paper describes a visualization tool which is a component of the NYNEX Network Exploratorium, a decision support platform for telephone interoffice network planning. The visualization tool provides a number of visualization styles suited to knowledge discovery in the network planning domain, and is designed for expansion to support additional styles. Visualizations are specific using a declarative language, which binds

Gary S. Sevitsky; John Martin; Michelle Zhou; Afshin Goodarzi; Henry Rabinowitz

1996-01-01

459

A networked robot system for wireless network emulation  

Microsoft Academic Search

A major barrier to advancing modern wireless net- working research is the lack of an effective wireless network simu- lation platform that simultaneously offers high fidelity, scalability, reproducibility and ease of use. MiNT (8), (7) is an innovative wireless network emulation platform that is specifically designed to satisfy all these desirable properties. To support reconfigurable network topology and wireless node

Tzi-cker Chiueh; Rupa Krishnan; Pradipta De; Jui-hao Chiang

2007-01-01

460

40 CFR 58.10 - Annual monitoring network plan and periodic network assessment.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Annual monitoring network plan and periodic network assessment... AMBIENT AIR QUALITY SURVEILLANCE Monitoring Network § 58.10 Annual monitoring network plan and periodic network...

2010-07-01

461

Implications of Network Centric Warfare.  

National Technical Information Service (NTIS)

This paper will examine Network Centric Warfare the centerpiece of Transformation. This form of warfare depends heavily on computer networks the Internet communications and sensors. These areas of dependence also provide numerous vulnerabilities. This pap...

A. L. Bailey

2004-01-01

462

Exact controllability of complex networks  

NASA Astrophysics Data System (ADS)

Controlling complex networks is of paramount importance in science and engineering. Despite the recent development of structural controllability theory, we continue to lack a framework to control undirected complex networks, especially given link weights. Here we introduce an exact controllability paradigm based on the maximum multiplicity to identify the minimum set of driver nodes required to achieve full control of networks with arbitrary structures and link-weight distributions. The framework reproduces the structural controllability of directed networks characterized by structural matrices. We explore the controllability of a large number of real and model networks, finding that dense networks with identical weights are difficult to be controlled. An efficient and accurate tool is offered to assess the controllability of large sparse and dense networks. The exact controllability framework enables a comprehensive understanding of the impact of network properties on controllability, a fundamental problem towards our ultimate control of complex systems.

Yuan, Zhengzhong; Zhao, Chen; di, Zengru; Wang, Wen-Xu; Lai, Ying-Cheng

2013-09-01

463

Target Discrimination with Neural Networks.  

National Technical Information Service (NTIS)

The feasibility of discriminating the warhead from an intentionally segmented exoatmospheric threat missile is demonstrated by applying the time delay neural network (TDNN) and the adaptive time delay neural network (ATNN). Exoatmospheric threats are espe...

D. T. Lin J. Dayhoff C. Resh

1996-01-01

464

Review of Computer Networking Technology.  

National Technical Information Service (NTIS)

The report gives a descriptive summary of the technical characteristics of existing computer networks, including data communication technology and configuration related to support of resource sharing services for a computer network. Included are discussio...

R. P. Blanc

1974-01-01

465

Neural Network Communications Signal Processing.  

National Technical Information Service (NTIS)

This final technical report describes the research and development results of the Neural Network Communications Signal Processing (NNCSP) Program. The objectives of the NNCSP program are to: (1) develop and implement a neural network and communications si...

D. Tebbe J. Doner T. Billhartz

1994-01-01

466

Network model with structured nodes.  

PubMed

We present a network model in which words over a specific alphabet, called structures, are associated to each node and undirected edges are added depending on some distance measure between different structures. This model shifts the underlying principle of network generation from a purely mathematical one to an information-based one. It is shown how this model differs from the Barábasi-Albert and duplication models and how it can generate networks with topological features similar to biological networks: power law degree distribution, low average path length, clustering coefficient independent from the network size, etc. Two biological networks: S. cerevisiae gene network and E. coli protein-protein interaction network, are replicated using this model. PMID:21929042

Frisco, Pierluigi

2011-08-01

467

Semantic Networks and Neural Nets.  

National Technical Information Service (NTIS)

Connected networks of nodes representing conceptual knowledge are widely employed in artificial intelligence and cognitive science. This report describes a direct way of realizing these semantic networks with neuron-like computing units. The proposed fram...

L. Shastri J. A. Feldman

1984-01-01

468

Network model with structured nodes  

NASA Astrophysics Data System (ADS)

We present a network model in which words over a specific alphabet, called structures, are associated to each node and undirected edges are added depending on some distance measure between different structures. This model shifts the underlying principle of network generation from a purely mathematical one to an information-based one. It is shown how this model differs from the Barábasi-Albert and duplication models and how it can generate networks with topological features similar to biological networks: power law degree distribution, low average path length, clustering coefficient independent from the network size, etc. Two biological networks: S. cerevisiae gene network and E. coli protein-protein interaction network, are replicated using this model.

Frisco, Pierluigi

2011-08-01

469

Dynamic behaviors in directed networks  

SciTech Connect

Motivated by the abundance of directed synaptic couplings in a real biological neuronal network, we investigate the synchronization behavior of the Hodgkin-Huxley model in a directed network. We start from the standard model of the Watts-Strogatz undirected network and then change undirected edges to directed arcs with a given probability, still preserving the connectivity of the network. A generalized clustering coefficient for directed networks is defined and used to investigate the interplay between the synchronization behavior and underlying structural properties of directed networks. We observe that the directedness of complex networks plays an important role in emerging dynamical behaviors, which is also confirmed by a numerical study of the sociological game theoretic voter model on directed networks.

Park, Sung Min [Center of Complex Systems, Samsung Economic Research Institute, Seoul 140-702 (Korea, Republic of); Kim, Beom Jun [Department of Physics, BK21 Physics Research Division, and Institute of Basic Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

2006-08-15

470

Local Network Wideband Interconnection Alternatives.  

National Technical Information Service (NTIS)

Broadband local area networks are being acquired throughout the Air Force. This report addresses alternatives for interconnecting these networks. These alternatives support both data transmission at rates greater than 1.5 Mbps and two standard television ...

K. Erat J. P. Worthley

1984-01-01

471

Mathematical Theory of Neural Networks.  

National Technical Information Service (NTIS)

The work pursued under this grant dealt with artificial neural networks and other discrete/continuous models. New bounds were obtained for sample complexity for identification of static and dynamic concept classes defined by static and recurrent networks....

E. D. Sontag H. J. Sussman

2000-01-01

472

Neural Network for Feature Extraction.  

National Technical Information Service (NTIS)

This paper suggests a statistical framework for the parameter estimation problem associated with unsupervised learning in a neural network, leading to an exploratory projection pursuit network that performs feature extraction, or dimensionality reduction....

N. Intrator

1990-01-01

473

AIDS Clinical Trials Group Network  

MedlinePLUS

... ACTG Our Mission History of the ACTG Network Leadership Organizational Matrix State of the ACTG ACTG Operational ... and Forms Annual Progress Reports Performance Evaluation Program Leadership and Operations Center Network Coordinating Center Statistical and ...

474

Face Recognition with Neural Networks.  

National Technical Information Service (NTIS)

This study investigated neural networks for face verification and classification. The research concentrated on developing a neural network based feature extractor and/or classifier to perform authorized user verification in a realistic work environment. R...

D. L. Krepp

1992-01-01

475

Social Interaction in Learning Networks  

Microsoft Academic Search

The original publication is available from www.springerlink.com.\\u000aSloep, P. (2009). Social Interaction in Learning Networks. In R. Koper (Ed.), Learning Network Services for Professional Development (pp 13-15). Berlin, Germany: Springer Verlag.

Peter Sloep

2009-01-01

476

Directory Enabled Policy Based Networking.  

National Technical Information Service (NTIS)

This report presents a discussion of directory-enabled policy-based networking with an emphasis on its role as the foundation for securely scalable enterprise networks. A directory service provides the object-oriented logical environment for interactive c...

C. M. Keliiaa

2001-01-01

477

Maths, Stats & OR Network  

NSDL National Science Digital Library

This site, authored by John Blake of Maths, Stats & OR Network, provides tutorials and applets which cover topics including analysis of variance, chi-square, descriptive statistics, discrete random variables, graphs and plots, operational research, probability, p-values, regression analysis, relationships, sampling distributions, specialized topics, statistical inference, normal distribution, and t-distribution. It also provides teaching resources on planning, assessments, and motivation.

Blake, John

2009-03-10

478

Collaboration in social networks  

PubMed Central

The very notion of social network implies that linked individuals interact repeatedly with each other. This notion allows them not only to learn successful strategies and adapt to them, but also to condition their own behavior on the behavior of others, in a strategic forward looking manner. Game theory of repeated games shows that these circumstances are conducive to the emergence of collaboration in simple games of two players. We investigate the extension of this concept to the case where players are engaged in a local contribution game and show that rationality and credibility of threats identify a class of Nash equilibria—that we call “collaborative equilibria”—that have a precise interpretation in terms of subgraphs of the social network. For large network games, the number of such equilibria is exponentially large in the number of players. When incentives to defect are small, equilibria are supported by local structures whereas when incentives exceed a threshold they acquire a nonlocal nature, which requires a “critical mass” of more than a given fraction of the players to collaborate. Therefore, when incentives are high, an individual deviation typically causes the collapse of collaboration across the whole system. At the same time, higher incentives to defect typically support equilibria with a higher density of collaborators. The resulting picture conforms with several results in sociology and in the experimental literature on game theory, such as the prevalence of collaboration in denser groups and in the structural hubs of sparse networks.

Dall'Asta, Luca; Marsili, Matteo; Pin, Paolo

2012-01-01

479

Onboard hierarchical network  

Microsoft Academic Search

The objective of this paper is to demonstrate a suitable hierarchical networking solution to improve capabilities and performances of space systems, with significant recurrent costs saving and more efficient design & manufacturing flows. Classically, a satellite can be split in two functional sub-systems: the platform and the payload complement. The platform is in charge of providing power, attitude & orbit

Luca Tunesi; Philippe Armbruster

2004-01-01

480

Prototyping distributed simulation networks  

NASA Technical Reports Server (NTRS)

Durra is a declarative language designed to support application-level programming. The use of Durra is illustrated to describe a simple distributed application: a simulation of a collection of networked vehicle simulators. It is shown how the language is used to describe the application, its components and structure, and how the runtime executive provides for the execution of the application.

Doubleday, Dennis L.

1990-01-01

481

Boosted Bayesian network classifiers  

Microsoft Academic Search

The use of Bayesian networks for classification problems has received a signifi- cant amount of recent attention. Although computationally efficient, the standard maximum likelihood learning method tends to be suboptimal due to the mismatch between its optimiza- tion criteria (data likelihood) and the actual goal of classification (label prediction accuracy). Recent approaches to optimizing classification performance during parameter or structure

Yushi Jing; Vladimir Pavlovic; James M. Rehg

2008-01-01

482

Statistics Teacher Network  

NSDL National Science Digital Library

This website provides links to all current and past issues of "The Statistics Teacher Network". This newsletter for K-12 teachers is published three times a year, and presents up to date articles that describe statistical activities that have been successful in the classroom. It also informs educators of statistical workshops, programs, and reviews of books, software, and calculators.

2012-01-01

483

BER Science Network Requirements  

SciTech Connect

The Energy Sciences Network (ESnet) is the primary provider of network connectivity for the US Department of Energy Office of Science, the single largest supporter of basic research in the physical sciences in the United States. In support of the Office of Science programs, ESnet regularly updates and refreshes its understanding of the networking requirements of the instruments, facilities, scientists, and science programs that it serves. This focus has helped ESnet to be a highly successful enabler of scientific discovery for over 20 years. In April 2010 ESnet and the Office of Biological and Environmental Research, of the DOE Office of Science, organized a workshop to characterize the networking requirements of the science programs funded by BER. The requirements identified at the workshop are summarized and described in more detail in the case studies and the Findings section. A number of common themes emerged from the case studies and workshop discussions. One is that BER science, like many other disciplines, is becoming more and more distributed and collaborative in nature. Another common theme is that data set sizes are exploding. Climate Science in particular is on the verge of needing to manage exabytes of data, and Genomics is on the verge of a huge paradigm shift in the number of sites with sequencers and the amount of sequencer data being generated.

Dart, Eli; Tierney, Brian

2010-11-01

484

Wireless sensor networks  

Microsoft Academic Search

Advances in commercial IC fabrication technology have made possible the integration of wireless transceivers, CMOS signal processing, and sensing in one integrated circuit package. Combination with actuation is also possible. This amounts to a low-cost means to link communications and computer networks to the physical world, and may have profound consequences in such diverse areas as security, process control, planetary

G. J. Pottie

1998-01-01

485

Networked Administration Streamlines Operations.  

ERIC Educational Resources Information Center

An Iowa school district has retooled its computer systems for more standardized administration. In addition to administration, the district is doing inhouse databasing of financial accounting, and doing inhouse scheduling and grade reporting. A partnership with the Chamber of Commerce contributed $500,000 for the network system. (MLF)

School Planning and Management, 1996

1996-01-01

486

Designing Networks for Innovation  

ERIC Educational Resources Information Center

The last decades have seen tremendous growth and transformation in the Internet's commercial landscape. Underneath this success, however, the underlying network architecture has shown a marked resistance to change; it is now described as stagnant and ossified. Numerous design proposals have been developed by researchers, implemented in code, and…

Laskowski, Paul Luke

2009-01-01

487

WATERSHED INFORMATION NETWORK  

EPA Science Inventory

Resource Purpose: The Watershed Information Network is a set of about 30 web pages that are organized by topic. These pages access existing databases like the American Heritage Rivers Services database and Surf Your Watershed. WIN in itself has no data or data sets. L...

488

Communicability across evolving networks.  

PubMed

Many natural and technological applications generate time-ordered sequences of networks, defined over a fixed set of nodes; for example, time-stamped information about "who phoned who" or "who came into contact with who" arise naturally in studies of communication and the spread of disease. Concepts and algorithms for static networks do not immediately carry through to this dynamic setting. For example, suppose A and B interact in the morning, and then B and C interact in the afternoon. Information, or disease, may then pass from A to C, but not vice versa. This subtlety is lost if we simply summarize using the daily aggregate network given by the chain A-B-C. However, using a natural definition of a walk on an evolving network, we show that classic centrality measures from the static setting can be extended in a computationally convenient manner. In particular, communicability indices can be computed to summarize the ability of each node to broadcast and receive information. The computations involve basic operations in linear algebra, and the asymmetry caused by time's arrow is captured naturally through the noncommutativity of matrix-matrix multiplication. Illustrative examples are given for both synthetic and real-world communication data sets. We also discuss the use of the new centrality measures for real-time monitoring and prediction. PMID:21599253

Grindrod, Peter; Parsons, Mark C; Higham, Desmond J; Estrada, Ernesto

2011-04-01

489

STREAM NETWORK TEMPERATURE  

EPA Science Inventory

The Stream Network Temperature (SNTEMP) model is a mechanistic, one-dimensional heat transport formulation that predicts daily mean and maximum water temperature as a function of stream distance and environmental heat flux. Net heat flux is calculated as the sum of heat to or fr...

490

Great Lakes Information Network  

NSDL National Science Digital Library

The Great Lakes Information Network (GLIN) is a partnership that has compiled information relating to the binational Great Lakes-St. Lawrence region of North America. Sections of the site include an overview of the Great Lakes, the environment of the Great Lakes, the economy of the Great Lakes, education, maps and Geographic Information Systems (GIS), and tourism.

2007-10-26

491

Great Lakes Information Network  

NSDL National Science Digital Library

The Great Lakes Information Network (GLIN) is a partnership that has compiled information relating to the binational Great Lakes-St. Lawrence region of North America. Sections of the site include an overview of the Great Lakes, the environment of the Great Lakes, the economy of the Great Lakes, education, maps and Geographic Information Systems (GIS), and tourism.

492

Network Coordinator Report  

NASA Technical Reports Server (NTRS)

This report includes an assessment of the network performance in terms of the yield of usable data over a 12 month period. A table of relative incidence of problems with various subsystems is presented. The current situation for the handling of correlator clock adjustments by the correlators is reviewed.

Himwich, Ed

2004-01-01

493

Network Directory Services.  

ERIC Educational Resources Information Center

Explains how the Directory Service (CCITT X.500/ISO 9594) became an international standard in response to the difficulties of keeping data on information network users current and accessible. Uses of X.500 are described, a technical overview is provided, its functions and protocols are assessed, and directory projects and products are discussed.…

Planka, Daniela

1990-01-01

494

NASA Engineering Network (NEN)  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the NASA Engineering Network (NEN). NEN is designed to search documents over multiple repositories, submit and browse NASA Lessons Learned, collaborate and share ideas with other engineers via communities of practice, access resources from one portal, and find subject matter experts via the People, Organizations, Projects, Skills (POPS) locator.

Topousis, Daria; Trevarthen, Ellie; Yew, Manson

2008-01-01

495

K-12 Computer Networking.  

ERIC Educational Resources Information Center

The "ERIC Review" is published three times a year and announces research results, publications, and new programs relevant to each issue's theme topic. This issue is intended to help teacher educators, administrators, librarians, adult educators, and individual teachers introduce others to education resources on computer networks. There are nine…

ERIC Review, 1995

1995-01-01

496

Interacting Neural Networks  

Microsoft Academic Search

Several scenarios of interacting neural networks which are trained either in an identical or in a competitive way are solved analytically. In the case of identical training each perceptron receives the output of its neighbour. The symmetry of the stationary state as well as the sensitivity to the used training algorithm are investigated. Two competitive perceptrons trained on mutually exclusive

R. Metzler; I. Kanter

2000-01-01

497

Evolving artificial neural networks  

Microsoft Academic Search

Learning and evolution are two fundamental forms of adaptation. There has been a great interest in combining learning and evolution with artificial neural networks (ANNs) in recent years. This paper: 1) reviews different combinations between ANNs and evolutionary algorithms (EAs), including using EAs to evolve ANN connection weights, architectures, learning rules, and input features; 2) discusses different search operators which

Xin Yao

1999-01-01

498

Critical Branching Neural Networks  

ERIC Educational Resources Information Center

It is now well-established that intrinsic variations in human neural and behavioral activity tend to exhibit scaling laws in their fluctuations and distributions. The meaning of these scaling laws is an ongoing matter of debate between isolable causes versus pervasive causes. A spiking neural network model is presented that self-tunes to critical…

Kello, Christopher T.

2013-01-01

499

Microsystem process networks  

DOEpatents

Various aspects and applications of microsystem process networks are described. The design of many types of microsystems can be improved by ortho-cascading mass, heat, or other unit process operations. Microsystems having exergetically efficient microchannel heat exchangers are also described. Detailed descriptions of numerous design features in microcomponent systems are also provided.

Wegeng, Robert S. (Richland, WA); TeGrotenhuis, Ward E. (Kennewick, WA); Whyatt, Greg A. (West Richland, WA)

2006-10-24

500

Structurally robust biological networks  

PubMed Central

Background The molecular circuitry of living organisms performs remarkably robust regulatory tasks, despite the often intrinsic variability of its components. A large body of research has in fact highlighted that robustness is often a structural property of biological systems. However, there are few systematic methods to mathematically model and describe structural robustness. With a few exceptions, numerical studies are often the preferred approach to this type of investigation. Results In this paper, we propose a framework to analyze robust stability of equilibria in biological networks. We employ Lyapunov and invariant sets theory, focusing on the structure of ordinary differential equation models. Without resorting to extensive numerical simulations, often necessary to explore the behavior of a model in its parameter space, we provide rigorous proofs of robust stability of known bio-molecular networks. Our results are in line with existing literature. Conclusions The impact of our results is twofold: on the one hand, we highlight that classical and simple control theory methods are extremely useful to characterize the behavior of biological networks analytically. On the other hand, we are able to demonstrate that some biological networks are robust thanks to their structure and some qualitative properties of the interactions, regardless of the specific values of their parameters.

2011-01-01

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