EFFECTS OF TRAFFIC PROPERTIES AND DEGREE HETEROGENEITY IN FLOW FLUCTUATIONS ON COMPLEX NETWORKS

2012 ◽  
Vol 22 (07) ◽  
pp. 1250170 ◽  
Author(s):  
SANDRO MELONI ◽  
JESÚS GÓMEZ-GARDEÑES ◽  
VITO LATORA ◽  
YAMIR MORENO
Keyword(s):  
Standard Deviation ◽  
Numerical Simulations ◽  
Communication Networks ◽  
Communication Systems ◽  
Great Influence ◽  
Real Data ◽  
Mean Values ◽  
Flow Fluctuations ◽  
Routing Strategy ◽  
The Relationship

Communication networks are nowadays crucial in our lives and the study of the traffic features yields important advantages. In both network and traffic design, the understanding of the relationship between the traffic on a node and its fluctuations plays a key role. In this paper, we investigate the relationship between the mean traffic flow experienced by a node and its standard deviation via numerical simulations and real data analysis. In particular, we show the great influence that the degree heterogeneity of real communication systems has on the patterns of flow fluctuations observed across complex communication networks. To this end, we derive an analytical law connecting the standard deviation of flows and their mean values, we prove it via extensive numerical simulations and by means of a realistic internet traffic simulator software: NS-3. We also show that our results are robust under different assumptions regarding network topology, routing strategy and packets injection distributions.

scholarly journals The Relationship between the Madden–Julian Oscillation and U.S. Violent Tornado Outbreaks in the Spring

2013 ◽  
Vol 141 (6) ◽  
pp. 2087-2095 ◽  
Author(s):  
Daniel B. Thompson ◽  
Paul E. Roundy
Keyword(s):  
Standard Deviation ◽  
Large Scale ◽  
Low Frequency ◽  
The United States ◽  
Madden Julian Oscillation ◽  
Phase 2 ◽  
Frequency Pattern ◽  
Mean Values ◽  
The Relationship ◽  
Tornado Outbreaks

Abstract The Madden–Julian oscillation (MJO) has been linked to weather variability in the midlatitudes via its associated overturning circulations and Rossby wave trains that redistribute the thermal and mass fields at higher latitudes. This work examines the relationship between the MJO and violent tornado outbreaks in the United States. A census of events shows that violent tornado outbreaks during March–April–May (MAM) are more than twice as frequent during phase 2 of the Real-time Multivariate MJO (RMM) index as during other phases or when the MJO was deemed inactive. Composite analyses show the global circulation patterns simultaneously associated with the MJO and the tornado outbreaks and also indicate the most favored low-frequency circulation pattern that precedes tornado outbreaks in RMM phase 2. An index of 300-hPa geopotential height data is generated by projecting 60-day mean values onto the composite low-frequency pattern. When that index exceeds one standard deviation and the MJO is in RMM phase 2 with an amplitude exceeding one standard deviation during MAM, violent tornado outbreaks occur 50% of the time, relative to the average frequency of less than 4%. Results demonstrate that the anomalous large-scale midlatitude circulation modulated by the MJO and lower-frequency signals can make conditions more or less favorable for tornado outbreaks.

Effect of Formation Nonuniformity on the Mechanical Strength of Aramid Paper

2011 ◽  
Vol 236-238 ◽  
pp. 1265-1270
Author(s):  
Hui Fang Zhao ◽  
Mei Yun Zhang
Keyword(s):  
Tensile Strength ◽  
Standard Deviation ◽  
Ethylene Oxide ◽  
Mechanical Strength ◽  
Great Influence ◽  
Fiber Distribution ◽  
Tear Strength ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
The Relationship

Aramid paper was manufactured using poly (m-phenyleneisophthalamide) (PMIA) fibers and fibrids, and poly(ethylene oxide) (PEO) was used as dispersant to improve the uniformity of fiber distribution. The Paper Perfect Formation Analyzer (PPF) and the BFT-1 type β Formation tester were used to determine the formation of the aramid paper, and the relationship between the formation and the mechanical strength of aramid paper was discussed. Results showed that the tensile strength and tear strength of aramid paper before hot calendering is affected strongly by its grammage standard deviation, but is less affected by its formation nonuniformity as a function of the scale of foramtion, the R2 correlation between tensile strength and grammage standard deviation was 0.63, and the R2 correlation between tear strength and grammage standard deviation was 0.73. However, the nonuniformity of formation in the range of scale of formation 0.8-22.7mm has great influence on the tensile strength of aramid paper after hot calendering, and the R2 correlation between tensile strength and formation nonuniformity in this range of scale of formation was greater than 0.58.

scholarly journals Subscriber and inter-satellite paths in LEO communications networks

2019 ◽  
Vol 29 (3) ◽  
pp. 48-54
Author(s):  
S. B. Pichugin
Keyword(s):  
Communication Networks ◽  
Communication Systems ◽  
Satellite Communications ◽  
Communications Networks ◽  
Advantages And Disadvantages ◽  
Commercial Use ◽  
Radio Band ◽  
Technical Solutions ◽  
The Relationship ◽  
Current Stage

The purpose of the study is to propose and substantiate technical solutions for inter-satellite and subscriber paths of loworbit communication networks. There is a prospect of commercial use of such networks; therefore, the current stage of low-orbit satellite communications development is characterized by an increase in efforts to put the projects into practice. As part of the study, solutions for inter-satellite paths (ISP) in low-orbit communication systems and solutions that increase the capacity of their subscriber paths are considered. It is noted that ISPs can be built on the basis of radio and optical bands equipment. In this regard, the advantages and disadvantages of each case are considered. The expediency of constructing subscriber paths based on radio band equipment and the preference of constructing ISP based on optical band equipment are substantiated. The relationship between the feasibility of increasing the capacity of subscriber paths and the capabilities of ISP in terms of reliability and bandwidth is established.

scholarly journals A Framework Coupling VISSIM and OMNeT++ to Simulate Future Intelligent Transportation Systems

2021 ◽  
Vol 23 (2) ◽  
pp. C23-C29
Author(s):  
Tibor Petrov ◽  
Ilya Finkelberg ◽  
Nina Zarkhin ◽  
Peter Počta ◽  
Ľuboš Buzna ◽  
...  
Keyword(s):  
Communication Networks ◽  
Intelligent Transportation Systems ◽  
Communication Systems ◽  
Transportation Systems ◽  
Transport Systems ◽  
Wireless Communication Systems ◽  
Intelligent Transport ◽  
Transmission Reliability ◽  
The Relationship

With the spread of connected vehicles (CVs), a growth of novel information services exploiting data transmitted by CVs is expected. Wireless communication systems, in particular in vehicular applications, operate with a varying level of transmission reliability, which may affect the quality of V2X-data-driven intelligent transport systems (ITS). Therefore, the performance of ITS should be evaluated in a variety of conditions and the configuration of parameters should be fine-tuned in a safe testbed, using computer simulations. A simple framework is presented, which couples VISSIM traffic simulation and OMNeT++ communication networks simulation in real time, enabling an assessment of the relationship between a communication reliability and transport service quality. A functionality of the framework is demonstrated by applying it to a scheme controlling signalized intersections while estimating traffic flows from the V2I data.

Reliability of the Minimum Masking Level as Outcome Variable in Tinnitus Clinical Research

2020 ◽  
Vol 29 (3) ◽  
pp. 429-435
Author(s):  
Patricia C. Mancini ◽  
Richard S. Tyler ◽  
Hyung Jin Jun ◽  
Tang-Chuan Wang ◽  
Helena Ji ◽  
...  
Keyword(s):  
Standard Deviation ◽  
High Frequency ◽  
Pearson Correlation ◽  
Correlation Coefficients ◽  
Outcome Variable ◽  
Reliable Estimate ◽  
Moderate Correlation ◽  
Trained Subjects ◽  
The Relationship ◽  
Minimum Intensity

Purpose The minimum masking level (MML) is the minimum intensity of a stimulus required to just totally mask the tinnitus. Treatments aimed at reducing the tinnitus itself should attempt to measure the magnitude of the tinnitus. The objective of this study was to evaluate the reliability of the MML. Method Sample consisted of 59 tinnitus patients who reported stable tinnitus. We obtained MML measures on two visits, separated by about 2–3 weeks. We used two noise types: speech-shaped noise and high-frequency emphasis noise. We also investigated the relationship between the MML and tinnitus loudness estimates and the Tinnitus Handicap Questionnaire (THQ). Results There were differences across the different noise types. The within-session standard deviation averaged across subjects varied between 1.3 and 1.8 dB. Across the two sessions, the Pearson correlation coefficients, range was r = .84. There was a weak relationship between the dB SL MML and loudness, and between the MML and the THQ. A moderate correlation ( r = .44) was found between the THQ and loudness estimates. Conclusions We conclude that the dB SL MML can be a reliable estimate of tinnitus magnitude, with expected standard deviations in trained subjects of about 1.5 dB. It appears that the dB SL MML and loudness estimates are not closely related.

Contribution a la rationalisation du reseau qualite de l’eau de la Baie James

1977 ◽  
Vol 12 (1) ◽  
pp. 51-76
Author(s):  
B. Bobée ◽  
D. Cluis ◽  
A. Tessier
Keyword(s):  
Correspondence Analysis ◽  
Major Ions ◽  
Base Station ◽  
Base Stations ◽  
James Bay ◽  
Mean Values ◽  
Multivariate Technique ◽  
Qualité De L’Eau ◽  
Concentration Changes ◽  
The Relationship

Abstract A water quality sampling programme for James Bay territory established in a previous study has been carried out for the Department of Natural Resources of the Province of Quebec. The network is composed of 5 base-stations, sampled every fortnight to determine the variability with time of the parameters and 16 satellite-stations, sampled five times yearly with a view to determine the spatial variability. The data (major ions and certain nutrients) gathered during the 1974–1975 field survey are subjected to an analysis by a multivariate technique (correspondence analysis) in addition to certain classical statistical methods. The latter have shown that the mean values obtained at satellite stations were representative of the annual mean. In addition, the results permit the determination for a given parameter, of the relationship between stations and, for a given station, the relationship between parameters. In both cases, the formulation of predictive equations was attempted. An overall evaluation of the data by correspondence analysis has permitted: - a more precise definition of the qualitative behaviour of the different sub-basins of the James Bay territory and characterization of their waters;- a proof of the existence of gradual concentration changes in both East-West and North-South directions. Within the original objectives of the network, the results of the study have led to the following recommendations: - to continue synchronised samplings;- to transform a base station with a low information content into a satellite station;- to create a new base station in the eastern part of the territory.

scholarly journals The Flexible Burr X-G Family: Properties, Inference, and Applications in Engineering Science

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 474
Author(s):  
Abdulhakim A. Al-Babtain ◽  
Ibrahim Elbatal ◽  
Hazem Al-Mofleh ◽  
Ahmed M. Gemeay ◽  
Ahmed Z. Afify ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Exponential Distribution ◽  
Real Data ◽  
Exponential Model ◽  
Statistical Properties ◽  
Engineering Science ◽  
Data Sets ◽  
Engineering Sciences ◽  
General Statistical ◽  
Anderson Darling

In this paper, we introduce a new flexible generator of continuous distributions called the transmuted Burr X-G (TBX-G) family to extend and increase the flexibility of the Burr X generator. The general statistical properties of the TBX-G family are calculated. One special sub-model, TBX-exponential distribution, is studied in detail. We discuss eight estimation approaches to estimating the TBX-exponential parameters, and numerical simulations are conducted to compare the suggested approaches based on partial and overall ranks. Based on our study, the Anderson–Darling estimators are recommended to estimate the TBX-exponential parameters. Using two skewed real data sets from the engineering sciences, we illustrate the importance and flexibility of the TBX-exponential model compared with other existing competing distributions.

scholarly journals Towards DC Energy Efficient Homes

2021 ◽  
Vol 11 (13) ◽  
pp. 6005
Author(s):  
Daniel Villanueva ◽  
Moisés Cordeiro-Costas ◽  
Andrés E. Feijóo-Lorenzo ◽  
Antonio Fernández-Otero ◽  
Edelmiro Miguez-García
Keyword(s):  
Energy Efficiency ◽  
Electric Vehicles ◽  
Energy Efficient ◽  
Electricity Consumption ◽  
Real Data ◽  
Mean Values ◽  
Led Lighting ◽  
Shed Light

The aim of this paper is to shed light on the question regarding whether the integration of an electric battery as a part of a domestic installation may increase its energy efficiency in comparison with a conventional case. When a battery is included in such an installation, two types of electrical conversion must be considered, i.e., AC/DC and DC/AC, and hence the corresponding losses due to these converters must not be forgotten when performing the analysis. The efficiency of the whole system can be increased if one of the mentioned converters is avoided or simply when its dimensioning is reduced. Possible ways to achieve this goal can be: to use electric vehicles as DC suppliers, the use of as many DC home devices as possible, and LED lighting or charging devices based on renewables. With all this in mind, several scenarios are proposed here in order to have a look at all possibilities concerning AC and DC powering. With the aim of checking these scenarios using real data, a case study is analyzed by operating with electricity consumption mean values.

scholarly journals Spatial pattern and genetic diversity estimates are linked in stochastic models of population differentiation

2000 ◽  
Vol 23 (3) ◽  
pp. 541-544 ◽  
Author(s):  
José Alexandre Felizola Diniz-Filho ◽  
Mariana Pires de Campos Telles
Keyword(s):  
Genetic Diversity ◽  
Spatial Pattern ◽  
Stochastic Models ◽  
Population Differentiation ◽  
Real Data ◽  
Population Heterogeneity ◽  
Data Set ◽  
Mantel’S Test ◽  
The Relationship ◽  
Diversity Estimates

In the present study, we used both simulations and real data set analyses to show that, under stochastic processes of population differentiation, the concepts of spatial heterogeneity and spatial pattern overlap. In these processes, the proportion of variation among and within a population (measured by G ST and 1 - G ST, respectively) is correlated with the slope and intercept of a Mantel's test relating genetic and geographic distances. Beyond the conceptual interest, the inspection of the relationship between population heterogeneity and spatial pattern can be used to test departures from stochasticity in the study of population differentiation.

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