WorldWideScience

Sample records for network measurements homepage

  1. Eine Homepage erstellen

    OpenAIRE

    Plieninger, Jürgen

    2005-01-01

    Wie man für eine kleine Bibliothek eine Homepage plant, konzipiert, gestaltet, erstellt, inhaltlich füllt, pflegt und evaluiert, wird hier in knappen Stichpunkten erläutert. This tutorial deals with how to plan, concept, create, fill with informations and services a homepage for a small library.

  2. The Other Homepage.

    Science.gov (United States)

    Kupersmith, John

    2003-01-01

    Examines special-purpose entry points to library Web sites. Discusses in-house homepages; branch-specific pages or single library system-wide pages; staff use pages; versions in different languages; "MyLibrary" pages where users can customize the menu; standalone "branded" sites; publicly accessible pages; and best practices.…

  3. Homepages: Built-in Motivation.

    Science.gov (United States)

    McKenzie, Cheryl

    2000-01-01

    Describes a Web-building class aimed at motivating English-as-a-Foreign-Language students to improve their English writing and editing skills while building a homepage. All students had a basic or better knowledge of keyboarding and Internet search techniques, two had advanced computer skills, but none had ever created a homepage. (Author/VWL)

  4. The cytochrome p450 homepage.

    Science.gov (United States)

    Nelson, David R

    2009-10-01

    The Cytochrome P450 Homepage is a universal resource for nomenclature and sequence information on cytochrome P450 ( CYP ) genes. The site has been in continuous operation since February 1995. Currently, naming information for 11,512 CYPs are available on the web pages. The P450 sequences are manually curated by David Nelson, and the nomenclature system conforms to an evolutionary scheme such that members of CYP families and subfamilies share common ancestors. The organisation and content of the Homepage are described.

  5. World Wide Web Homepage Design.

    Science.gov (United States)

    Tillman, Michael L.

    This paper examines hypermedia design and draws conclusions about how educational research and theory applies to various aspects of World Wide Web (WWW) homepage design. "Hypermedia" is defined as any collection of information which may be textual, graphical, visual, or auditory in nature and which may be accessed via a nonlinear route.…

  6. A Structured Approach to Homepage Design.

    Science.gov (United States)

    Gregory, Gwen; Brown, M. Marlo

    With no standards governing their creation, a variety of formats are being used for World Wide Web homepages. Some are well organized, present their information clearly, and work with multiple browsers. Others, however, are slow to load, function poorly with some Web browsing software, and are so badly structured that they are very difficult to…

  7. Build a WWW Homepage for Your School!

    Science.gov (United States)

    Chrobak, Kimberly

    1995-01-01

    Discusses the use of World Wide Web (WWW) Homepage for school information. Topics include school sites; installation of a WWW browser; file tags; sites for beginner's guides to the language (HTML); two Usenet discussion groups; and a sample lesson plan including objective, procedure, and evaluation. (AEF)

  8. Homepage for the Global Tropospheric Experiment

    Science.gov (United States)

    Ward, Eugene

    1995-01-01

    The objective of my NASA summer research project was to create a homepage to describe and present results from the NASA Global Tropospheric Experiment (GTE). The GTE is a major component of NASA's Tropospheric Chemistry Program and is managed in the Atmospheric Studies Branch, Atmospheric Sciences Division at the NASA Langley Research Center.

  9. Spectrum and network measurements

    CERN Document Server

    Witte, Robert A

    2014-01-01

    This new edition of Spectrum and Network Measurements enables readers to understand the basic theory, relate it to measured results, and apply it when creating new designs. This comprehensive treatment of frequency domain measurements successfully consolidates all the pertinent theory into one text. It covers the theory and practice of spectrum and network measurements in electronic systems. It also provides thorough coverage of Fourier analysis, transmission lines, intermodulation distortion, signal-to-noise ratio and S-parameters.

  10. Personal Homepage Construction as an Expression of Social Development

    Science.gov (United States)

    Schmitt, Kelly L.; Dayanim, Shoshana; Matthias, Stacey

    2008-01-01

    In 2 studies, the authors explored preadolescent and adolescent use of personal homepages in relation to mastery and identity formation. In Study 1, the authors attempted to determine the prevalence of personal homepage and online journal (blog) construction among a random sample (N = 500) of preadolescents and adolescents. Adolescents were more…

  11. Research and development cooperation project on environmental measurement using laser radar in fiscal 1995 (environmental network); Kankyo keisokuyo laser radar no kaihatsu ni kansuru kenkyu kyoryoku (kankyo network)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    As a part of the cooperative work with Indonesia of R and D of a laser radar for environmental measurement, the paper described the development of an environmental network. The field survey was conducted in April, July and December 1995 and in March 1996. For the investigational research, five meetings of the committee and four times of group work were held. The Asian environmental network was studied in terms of its arrangement, operation and management, and the overall network/path control design were being prepared. To make the persons concerned abroad and in Japan understood the APEC Osaka Conference held in November 1995, a homepage APEC `95 Kansai was opened using WWW (World Wide Web, a decentralized hyper media system which can dispatch information to the whole world by network using hyper text). Moreover, in connection with this, a homepage was opened of CICC (Center of the International Cooperation for Computerization, a center controlling the whole Asian environmental information network system where E-mail and data are exchangeable with Indonesia via Tokyo NOC (Network Operation Center)). 49 figs., 8 tabs.

  12. Homepage of the Philosophy Meets Popular Culture Initiative

    DEFF Research Database (Denmark)

    Grund, Cynthia M.

    2008-01-01

    -modern students, whose knowledge of various aspects of popular culture often is as encyclopedic as their classical liberal arts background is limited (some might say impoverished).   One goal of the PHILOSOPHY meets POPULAR CULTURE homepage (launched on October 7, 2008)  is to provide a forum for researchers, teachers...

  13. World Wide Web Homepages: An Examination of Content and Audience.

    Science.gov (United States)

    Reynolds, Betty; And Others

    This paper shows how the content of a World Wide Web page is selected and how an examination of the intended audience influences content. Examples from the New Mexico Tech (NMT) Library homepage show what sources are selected and what level of detail is appropriate for the intended audience. Six fundamental functions of libraries and information…

  14. Library Homepage Design at Smaller Bachelor of Arts Institutions

    Science.gov (United States)

    Jones, Scott L.; Leonard, Kirsten

    2011-01-01

    This study examined the homepages of the libraries of 175 smaller bachelor of arts institutions, coding for the presence of 98 design elements. By reporting and examining the frequency of these features, the authors noted what is and is not common practice at these libraries. They found that only fourteen elements were present on at least half of…

  15. Implementasi Seo Web Design Methodology Pada Official Homepage Pondok Pesantren Qodratullah

    OpenAIRE

    Ependi, Usman

    2013-01-01

    Homepage or website for an organization is a way to deliver information to the public. Now the number of homepage or website of the day is always increasing both personal or owned by the organization. To communicate or disseminate information homepage/ website Islamic Boarding School of Qodratullah need a surefire way to use the Search Engine Optimization Web Design Methodology. Conducted with the implementation of the Search Engine Optimization Web Design Methodology on the homepage/ website...

  16. Between altruism and narcissism: An action theoretical approach of personal homepages devoted to existential meaning

    NARCIS (Netherlands)

    Hijmans, E.J.S.; Selm, M. van

    2002-01-01

    This article aims to examine existential meaning constructions from an action theoretical perspective in a specific Internet environment: the personal homepage. Personal homepages are on-line multi-media documents addressing the question Who am I? Authors of personal homepages provide information on

  17. Measuring distances between complex networks

    International Nuclear Information System (INIS)

    Andrade, Roberto F.S.; Miranda, Jose G.V.; Pinho, Suani T.R.; Lobao, Thierry Petit

    2008-01-01

    A previously introduced concept of higher order neighborhoods in complex networks, [R.F.S. Andrade, J.G.V. Miranda, T.P. Lobao, Phys. Rev. E 73 (2006) 046101] is used to define a distance between networks with the same number of nodes. With such measure, expressed in terms of the matrix elements of the neighborhood matrices of each network, it is possible to compare, in a quantitative way, how far apart in the space of neighborhood matrices two networks are. The distance between these matrices depends on both the network topologies and the adopted node numberings. While the numbering of one network is fixed, a Monte Carlo algorithm is used to find the best numbering of the other network, in the sense that it minimizes the distance between the matrices. The minimal value found for the distance reflects differences in the neighborhood structures of the two networks that arise only from distinct topologies. This procedure ends up by providing a projection of the first network on the pattern of the second one. Examples are worked out allowing for a quantitative comparison for distances among distinct networks, as well as among distinct realizations of random networks

  18. Measurement of Online Social Networks

    Science.gov (United States)

    Gjoka, Mina

    2010-01-01

    In recent years, the popularity of online social networks (OSN) has risen to unprecedented levels, with the most popular ones having hundreds of millions of users. This success has generated interest within the networking community and has given rise to a number of measurement and characterization studies, which provide a first step towards their…

  19. Development of the Homepage for the HANARO information platform

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, J. M.; Park, K. B.; Kim, H. R. [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-05-01

    I - Object and Importance- Following in the footsteps of internationalization and the information-oriented society, we need to open the HANARO to the public, and to serve more detailed, accurate, and varied information rapidly via the internet to enhance the HANARO Utilization efficiency. II- Scope and Contents- We develope the HANARO Homepage using ORACLE DBMS and APACJE, it has function as an information platform for HANARO. In this report, we describe its design, implementation, management and operation. III-Result -The HANARO homepage was developed successfully, and it was opened to HANARO users from March 20, 2002 through the KAERI-Net. IV- Proposal for Application-The data of HANARO should be processed and organized systematically for its better utilization. A supplementation of the functions is needed and the HANARO web should be operated practically with maximum efficiency and advertise the activities locally and internationally. 3 refs., 11 figs., 9 tabs. (Author)

  20. Hierarchy Measure for Complex Networks

    Science.gov (United States)

    Mones, Enys; Vicsek, Lilla; Vicsek, Tamás

    2012-01-01

    Nature, technology and society are full of complexity arising from the intricate web of the interactions among the units of the related systems (e.g., proteins, computers, people). Consequently, one of the most successful recent approaches to capturing the fundamental features of the structure and dynamics of complex systems has been the investigation of the networks associated with the above units (nodes) together with their relations (edges). Most complex systems have an inherently hierarchical organization and, correspondingly, the networks behind them also exhibit hierarchical features. Indeed, several papers have been devoted to describing this essential aspect of networks, however, without resulting in a widely accepted, converging concept concerning the quantitative characterization of the level of their hierarchy. Here we develop an approach and propose a quantity (measure) which is simple enough to be widely applicable, reveals a number of universal features of the organization of real-world networks and, as we demonstrate, is capable of capturing the essential features of the structure and the degree of hierarchy in a complex network. The measure we introduce is based on a generalization of the m-reach centrality, which we first extend to directed/partially directed graphs. Then, we define the global reaching centrality (GRC), which is the difference between the maximum and the average value of the generalized reach centralities over the network. We investigate the behavior of the GRC considering both a synthetic model with an adjustable level of hierarchy and real networks. Results for real networks show that our hierarchy measure is related to the controllability of the given system. We also propose a visualization procedure for large complex networks that can be used to obtain an overall qualitative picture about the nature of their hierarchical structure. PMID:22470477

  1. Constructing hotel brands: A multimodal analysis of luxury hotel homepages

    Directory of Open Access Journals (Sweden)

    Fei-Wen Cheng

    2016-04-01

    Full Text Available As e-marketing has become the dominant marketing mode in the hospitality industry, this study investigates how two luxury hotels represent and promote themselves through their major e-commerce platforms (i.e. hotel-owned websites. The verbal and visual texts of 51 website homepages owned by these two hotel chains are compiled and analyzed by drawing upon the corpus linguistic approach for verbal analysis and Kress and van Leeuwen’s (2006 visual grammar framework for image analysis. The findings indicate that despite some similarities in their web-mediated communication strategies, each hotel firm has discursive strategies that reveal diverging attitudes in their choices of various semiotic resources to construct their own brand identities. This study contributes to the academic literature on web-mediated tourism discourse by showing how a multimodal analysis can add insights to brand formulation.

  2. Measurement methods on the complexity of network

    Institute of Scientific and Technical Information of China (English)

    LIN Lin; DING Gang; CHEN Guo-song

    2010-01-01

    Based on the size of network and the number of paths in the network,we proposed a model of topology complexity of a network to measure the topology complexity of the network.Based on the analyses of the effects of the number of the equipment,the types of equipment and the processing time of the node on the complexity of the network with the equipment-constrained,a complexity model of equipment-constrained network was constructed to measure the integrated complexity of the equipment-constrained network.The algorithms for the two models were also developed.An automatic generator of the random single label network was developed to test the models.The results show that the models can correctly evaluate the topology complexity and the integrated complexity of the networks.

  3. Critical field measurements in a superconducting networks

    International Nuclear Information System (INIS)

    Pannetier, B.; Chaussy, J.; Rammal, R.

    1984-01-01

    We have measured the critical field of a periodic two-dimensional network of superconducting indium. At low fields, the critical line Hsub(c)(T) reflects the network topology and exhibits well-defined cusps due to flux quantization corresponding to both integer and rational number of flux quanta phi 0 = h/2e per unit loop of the network [fr

  4. Launching a palliative care homepage: the Edmonton experience.

    Science.gov (United States)

    Pereira, J; Macmillan, A; Bruera, E

    1997-11-01

    The Internet, with its graphical subdivision, the World Wide Web (WWW). has become a powerful tool for the dissemination of information and for communication. This paper discusses the authors' experiences with creating, launching and maintaining an official publication on the Internet by the Edmonton Regional Palliative Care Program and the Division of Palliative Medicine, University of Alberta, Canada. It describes the content and format of the homepage and the process of publication. Over a six-month period there were 892 visits to the site and 84 separate items of correspondence to the site's editors. Of these correspondence items, 36 were requesting further information regarding clinical and other programme information. Sixty-nine of the 84 communications came from North America and Europe. The pattern of readership is briefly discussed as are some of the potential advantages and challenges when utilizing this electronic medium. To promote the dissemination of reliable information on the Internet, the authors encourage other palliative care groups and organizations to publish on the WWW. The URL is http:/(/)www.palliative.org (previously http:/(/)www.caritas.ab.ca/approximately palliate).

  5. Instantiating a Global Network Measurement Framework

    Energy Technology Data Exchange (ETDEWEB)

    Tierney, Brian L.; Boote, Jeff; Boyd, Eric; Brown, Aaron; Grigoriev, Maxim; Metzger, Joe; Swany, Martin; Zekauskas, Matt; Zurawski, Jason

    2008-12-15

    perfSONAR is a web services-based infrastructure for collecting and publishing network performance monitoring. A primary goal of perfSONAR is making it easier to solve end-to-end performance problems on paths crossing several networks. It contains a set of services delivering performance measurements in a federated environment. These services act as an intermediate layer, between the performance measurement tools and the diagnostic or visualization applications. This layer is aimed at making and exchanging performance measurements across multiple networks and multiple user communities, using well-defined protocols. This paper summarizes the key perfSONAR components, and describes how they are deployed by the US-LHC community to monitor the networks distributing LHC data from CERN. All monitoring data described herein is publicly available, and we hope the availability of this data via a standard schema will inspire others to contribute to the effort by building network data analysis applications that use perfSONAR.

  6. Investments in power networks and alternative measures

    International Nuclear Information System (INIS)

    2003-01-01

    Measures taken with respect to production and consumption are often alternatives to investments in the power networks. While decisions about production and consumption are taken in the market, the network operation is subject to monopoly regulation. In the central network, Statnett's commission is to invest on the basis of socioeconomic profitability. There is a need for much better coordination between network investments and other measures in the power system. The price signal from the market and general tariffs are not sufficient to realize optimal solutions, and there is a need for a ''visible hand'' that can contribute to the realization of the solutions that are the best in each individual situation. It is desirable to create processes and incentives that realize the best solutions, independently of dealing with network investments, local power production or other measures.

  7. Toward Measuring Network Aesthetics Based on Symmetry

    Directory of Open Access Journals (Sweden)

    Zengqiang Chen

    2017-05-01

    Full Text Available In this exploratory paper, we discuss quantitative graph-theoretical measures of network aesthetics. Related work in this area has typically focused on geometrical features (e.g., line crossings or edge bendiness of drawings or visual representations of graphs which purportedly affect an observer’s perception. Here we take a very different approach, abandoning reliance on geometrical properties, and apply information-theoretic measures to abstract graphs and networks directly (rather than to their visual representaions as a means of capturing classical appreciation of structural symmetry. Examples are used solely to motivate the approach to measurement, and to elucidate our symmetry-based mathematical theory of network aesthetics.

  8. Correlated measurement error hampers association network inference

    NARCIS (Netherlands)

    Kaduk, M.; Hoefsloot, H.C.J.; Vis, D.J.; Reijmers, T.; Greef, J. van der; Smilde, A.K.; Hendriks, M.M.W.B.

    2014-01-01

    Modern chromatography-based metabolomics measurements generate large amounts of data in the form of abundances of metabolites. An increasingly popular way of representing and analyzing such data is by means of association networks. Ideally, such a network can be interpreted in terms of the

  9. Settings in Social Networks : a Measurement Model

    NARCIS (Netherlands)

    Schweinberger, Michael; Snijders, Tom A.B.

    2003-01-01

    A class of statistical models is proposed that aims to recover latent settings structures in social networks. Settings may be regarded as clusters of vertices. The measurement model is based on two assumptions. (1) The observed network is generated by hierarchically nested latent transitive

  10. Centrality measures for immunization of weighted networks

    Directory of Open Access Journals (Sweden)

    Mohammad Khansari

    2016-03-01

    Full Text Available Effective immunization of individual communities with minimal cost in vaccination has made great discussion surrounding the realm of complex networks. Meanwhile, proper realization of relationship among people in society and applying it to social networks brings about substantial improvements in immunization. Accordingly, weighted graph in which link weights represent the intensity and intimacy of relationships is an acceptable approach. In this work we employ weighted graphs and a wide variety of weighted centrality measures to distinguish important individuals in contagion of diseases. Furthermore, we propose new centrality measures for weighted networks. Our experimental results show that Radiality-Degree centrality is satisfying for weighted BA networks. Additionally, PageRank-Degree and Radiality-Degree centralities showmoreacceptable performance in targeted immunization of weighted networks.

  11. Inverting radiometric measurements with a neural network

    Science.gov (United States)

    Measure, Edward M.; Yee, Young P.; Balding, Jeff M.; Watkins, Wendell R.

    1992-02-01

    A neural network scheme for retrieving remotely sensed vertical temperature profiles was applied to observed ground based radiometer measurements. The neural network used microwave radiance measurements and surface measurements of temperature and pressure as inputs. Because the microwave radiometer is capable of measuring 4 oxygen channels at 5 different elevation angles (9, 15, 25, 40, and 90 degs), 20 microwave measurements are potentially available. Because these measurements have considerable redundancy, a neural network was experimented with, accepting as inputs microwave measurements taken at 53.88 GHz, 40 deg; 57.45 GHz, 40 deg; and 57.45, 90 deg. The primary test site was located at White Sands Missile Range (WSMR), NM. Results are compared with measurements made simultaneously with balloon borne radiosonde instruments and with radiometric temperature retrievals made using more conventional retrieval algorithms. The neural network was trained using a Widrow-Hoff delta rule procedure. Functions of date to include season dependence in the retrieval process and functions of time to include diurnal effects were used as inputs to the neural network.

  12. Radioactivity monitoring network: Measurements 1987

    International Nuclear Information System (INIS)

    1989-01-01

    Four papers are presented: radionuclide concentration measurement in aerosols, surface water and the wastes of the Vienna Central Clarification Plant respectively, and on tritium in Austrian lakes and rivers. (qui)

  13. Measure of robustness for complex networks

    Science.gov (United States)

    Youssef, Mina Nabil

    Critical infrastructures are repeatedly attacked by external triggers causing tremendous amount of damages. Any infrastructure can be studied using the powerful theory of complex networks. A complex network is composed of extremely large number of different elements that exchange commodities providing significant services. The main functions of complex networks can be damaged by different types of attacks and failures that degrade the network performance. These attacks and failures are considered as disturbing dynamics, such as the spread of viruses in computer networks, the spread of epidemics in social networks, and the cascading failures in power grids. Depending on the network structure and the attack strength, every network differently suffers damages and performance degradation. Hence, quantifying the robustness of complex networks becomes an essential task. In this dissertation, new metrics are introduced to measure the robustness of technological and social networks with respect to the spread of epidemics, and the robustness of power grids with respect to cascading failures. First, we introduce a new metric called the Viral Conductance (VCSIS ) to assess the robustness of networks with respect to the spread of epidemics that are modeled through the susceptible/infected/susceptible (SIS) epidemic approach. In contrast to assessing the robustness of networks based on a classical metric, the epidemic threshold, the new metric integrates the fraction of infected nodes at steady state for all possible effective infection strengths. Through examples, VCSIS provides more insights about the robustness of networks than the epidemic threshold. In addition, both the paradoxical robustness of Barabasi-Albert preferential attachment networks and the effect of the topology on the steady state infection are studied, to show the importance of quantifying the robustness of networks. Second, a new metric VCSIR is introduced to assess the robustness of networks with respect

  14. Risk measures on networks and expected utility

    International Nuclear Information System (INIS)

    Cerqueti, Roy; Lupi, Claudio

    2016-01-01

    In reliability theory projects are usually evaluated in terms of their riskiness, and often decision under risk is intended as the one-shot-type binary choice of accepting or not accepting the risk. In this paper we elaborate on the concept of risk acceptance, and propose a theoretical framework based on network theory. In doing this, we deal with system reliability, where the interconnections among the random quantities involved in the decision process are explicitly taken into account. Furthermore, we explore the conditions to be satisfied for risk-acceptance criteria to be consistent with the axiomatization of standard expected utility theory within the network framework. In accordance with existing literature, we show that a risk evaluation criterion can be meaningful even if it is not consistent with the standard axiomatization of expected utility, once this is suitably reinterpreted in the light of networks. Finally, we provide some illustrative examples. - Highlights: • We discuss risk acceptance and theoretically develop this theme on the basis of network theory. • We propose an original framework for describing the algebraic structure of the set of the networks, when they are viewed as risks. • We introduce the risk measures on networks, which induce total orders on the set of networks. • We state conditions on the risk measures on networks to let the induced risk-acceptance criterion be consistent with a new formulation of the expected utility theory.

  15. Network Compression as a Quality Measure for Protein Interaction Networks

    Science.gov (United States)

    Royer, Loic; Reimann, Matthias; Stewart, A. Francis; Schroeder, Michael

    2012-01-01

    With the advent of large-scale protein interaction studies, there is much debate about data quality. Can different noise levels in the measurements be assessed by analyzing network structure? Because proteomic regulation is inherently co-operative, modular and redundant, it is inherently compressible when represented as a network. Here we propose that network compression can be used to compare false positive and false negative noise levels in protein interaction networks. We validate this hypothesis by first confirming the detrimental effect of false positives and false negatives. Second, we show that gold standard networks are more compressible. Third, we show that compressibility correlates with co-expression, co-localization, and shared function. Fourth, we also observe correlation with better protein tagging methods, physiological expression in contrast to over-expression of tagged proteins, and smart pooling approaches for yeast two-hybrid screens. Overall, this new measure is a proxy for both sensitivity and specificity and gives complementary information to standard measures such as average degree and clustering coefficients. PMID:22719828

  16. Measurement with Persons: A European Network

    NARCIS (Netherlands)

    Pendrill, L.R.; Emardson, R.; Berglund, B.; Gröning, M.; Höglund, A.; Cancedda, A.; Quinti, G.; Crenna, F.; Rossi, G.B.; Drnovek, J.; Gersak, G.; Goodman, T.; Harris, S.; Heijden, van der G.W.A.M.; Kallinen, K.; Ravaja, N.

    2010-01-01

    The European ‘Measuring the Impossible’ Network MINET promotes new research activities in measurement dependent on human perception and/or interpretation. This includes the perceived attributes of products and services, such as quality or desirability, and societal parameters such as security and

  17. Geographically Locating an Internet Node Using Network Latency Measurement

    National Research Council Canada - National Science Library

    Turnbaugh, Eugene

    2004-01-01

    .... The difficulties include accurate latency measure, network address translation (NAT) masking, service blocking, disparate physical configuration, dissimilar network hardware, and inaccurate and limited measuring tools...

  18. Measure of Node Similarity in Multilayer Networks

    DEFF Research Database (Denmark)

    Møllgaard, Anders; Zettler, Ingo; Dammeyer, Jesper

    2016-01-01

    The weight of links in a network is often related to the similarity of thenodes. Here, we introduce a simple tunable measure for analysing the similarityof nodes across different link weights. In particular, we use the measure toanalyze homophily in a group of 659 freshman students at a large...... university.Our analysis is based on data obtained using smartphones equipped with customdata collection software, complemented by questionnaire-based data. The networkof social contacts is represented as a weighted multilayer network constructedfrom different channels of telecommunication as well as data...... might bepresent in one layer of the multilayer network and simultaneously be absent inthe other layers. For a variable such as gender, our measure reveals atransition from similarity between nodes connected with links of relatively lowweight to dis-similarity for the nodes connected by the strongest...

  19. National network of radioactivity measurement in environment

    International Nuclear Information System (INIS)

    2006-01-01

    This document constitutes the report of management for the year 2006 of the national network of measurement of radioactivity in environment, instituted by the article R.1333-11 of the Public Health code. According to the 5. of the decree of 27. june 2005, the Institute of radiation protection and nuclear safety (I.R.S.N.) has for mission to write every year a report of management of the national network of radioactivity measurement in environment. This report has for principal objectives: to do an evaluation on organisation and functioning of the piloting committee; to realize a synthesis on the different tasks lead by the working groups; as well as on the human and financial resources devoted to this project; to debrief on the development project of the national network information system. This report must allow to the network actors, as to the professional people and the public, to understand the functioning of the national network and the process implemented for the development of centralization, management and public diffusion tools, of the radioactivity data in environment. The year 2006 was marked by the opening of an Internet gate of the national network. (N.C.)

  20. The Presentation of Self in Scholarly Life: Identity and Marginalization in Academic Homepages

    Science.gov (United States)

    Hyland, Ken

    2011-01-01

    The academic homepage is now a ubiquitous genre of scholarly life, but despite considerable interest in issues of identity and the ways individuals self-consciously manage the impression they give of themselves, it has been slow to attract the attention of ESP researchers. This may be because of the institutional control exercised by employing…

  1. Characteristics and Communication--Effectiveness of "Fortune 500" Company Corporate Homepages

    Science.gov (United States)

    Truell, Allen D.; Zhao, Jensen J.; Alexander, Melody W.; Whitesel, Joel A.

    2005-01-01

    The Internet and its component parts, email and the World Wide Web (Web), have had a tremendous impact on how companies communicate with their various audiences. Thus, the twofold purpose of this study was (a) to determine the characteristics of "Fortune 500" company homepage components and (b) to determine the communication effectiveness of…

  2. Measure of Node Similarity in Multilayer Networks.

    Directory of Open Access Journals (Sweden)

    Anders Mollgaard

    Full Text Available The weight of links in a network is often related to the similarity of the nodes. Here, we introduce a simple tunable measure for analysing the similarity of nodes across different link weights. In particular, we use the measure to analyze homophily in a group of 659 freshman students at a large university. Our analysis is based on data obtained using smartphones equipped with custom data collection software, complemented by questionnaire-based data. The network of social contacts is represented as a weighted multilayer network constructed from different channels of telecommunication as well as data on face-to-face contacts. We find that even strongly connected individuals are not more similar with respect to basic personality traits than randomly chosen pairs of individuals. In contrast, several socio-demographics variables have a significant degree of similarity. We further observe that similarity might be present in one layer of the multilayer network and simultaneously be absent in the other layers. For a variable such as gender, our measure reveals a transition from similarity between nodes connected with links of relatively low weight to dis-similarity for the nodes connected by the strongest links. We finally analyze the overlap between layers in the network for different levels of acquaintanceships.

  3. Network measures for characterising team adaptation processes

    NARCIS (Netherlands)

    Barth, S.K.; Schraagen, J.M.C.; Schmettow, M.

    2015-01-01

    The aim of this study was to advance the conceptualisation of team adaptation by applying social network analysis (SNA) measures in a field study of a paediatric cardiac surgical team adapting to changes in task complexity and ongoing dynamic complexity. Forty surgical procedures were observed by

  4. Measure of Node Similarity in Multilayer Networks

    DEFF Research Database (Denmark)

    Møllgaard, Anders; Zettler, Ingo; Dammeyer, Jesper

    2016-01-01

    university.Our analysis is based on data obtained using smartphones equipped with customdata collection software, complemented by questionnaire-based data. The networkof social contacts is represented as a weighted multilayer network constructedfrom different channels of telecommunication as well as data...... might bepresent in one layer of the multilayer network and simultaneously be absent inthe other layers. For a variable such as gender, our measure reveals atransition from similarity between nodes connected with links of relatively lowweight to dis-similarity for the nodes connected by the strongest...

  5. Traffic measurement for big network data

    CERN Document Server

    Chen, Shigang; Xiao, Qingjun

    2017-01-01

    This book presents several compact and fast methods for online traffic measurement of big network data. It describes challenges of online traffic measurement, discusses the state of the field, and provides an overview of the potential solutions to major problems. The authors introduce the problem of per-flow size measurement for big network data and present a fast and scalable counter architecture, called Counter Tree, which leverages a two-dimensional counter sharing scheme to achieve far better memory efficiency and significantly extend estimation range. Unlike traditional approaches to cardinality estimation problems that allocate a separated data structure (called estimator) for each flow, this book takes a different design path by viewing all the flows together as a whole: each flow is allocated with a virtual estimator, and these virtual estimators share a common memory space. A framework of virtual estimators is designed to apply the idea of sharing to an array of cardinality estimation solutions, achi...

  6. GEOGRAPHY nEtQUIPMENT to study geography: the homepage and reflections from the users

    Science.gov (United States)

    Pajtok-Tari, I.

    2009-04-01

    The main objective of the GEOGRAPHY nEtQUIPMENT is to convey structured information to teachers and pupils, as well as, professors and students of geography. This learning aid is a homepage, first published in Hungarian still in 2006 (http://netszkozkeszlet.ektf.hu), to help in orientation among the rapidly growing information on the Internet, to provide extra digitalized professional materials that are not yet available digitally and to share experiences of the teachers and professors working in the same area of interest and language environment. At present, its English version is already prepared and partly available at the same address. The GEOGRAPHY nEtQUIPMENT can be used free after registration, at present the homepage counts 2807 registered users. The interested user first enters a virtual office where the entries of the Menu can be opened by clicking at the drawer, shelf, wall map, globe, laptop, TV-set, etc. These entries are professional lesson plans using digital technology, photos, video clips, animations on physical and social geography. The homepage also mirrors pieces of music, maps, collection of minerals, database links, diagrams, bibliography, lecture notes, dictionaries, scientific and popular journals, geography games, web pages, etc. The whole set of appliances is based on Dreamweaver MX program. During the past 2.5 years some experience has been gained about the GEOGRAPHY nEtQUIPMENT in use, mainly from teachers of geography, who downloaded and responded to the questionnaire. Another source of information is the group of students in the College, where future teachers of geography are trained in a one-semester course on application of the Info-Communication Technology. From the first group, i.e. 59 active teachers of geography, 54 % use the Internet "always" or "frequently" in the classroom, whereas 75 % of them rely on it for preparation to the lessons. Before trying the homepage, these numbers were 25 % and 54 %, only. From among the listed

  7. Homepage to distribute the anatomy learning contents including Visible Korean products, comics, and books.

    Science.gov (United States)

    Chung, Beom Sun; Chung, Min Suk

    2018-03-01

    The authors have operated the homepage (http://anatomy.co.kr) to provide the learning contents of anatomy. From the homepage, sectioned images, volume models, and surface models-all Visible Korean products-can be downloaded. The realistic images can be interactively manipulated, which will give rise to the interest in anatomy. The various anatomy comics (learning comics, comic strips, plastination comics, etc.) are approachable. Visitors can obtain the regional anatomy book with concise contents, mnemonics, and schematics as well as the simplified dissection manual and the pleasant anatomy essay. Medical students, health allied professional students, and even laypeople are expected to utilize the easy and comforting anatomy contents. It is hoped that other anatomists successively produce and distribute their own informative contents.

  8. Homepage to distribute the anatomy learning contents including Visible Korean products, comics, and books

    Science.gov (United States)

    Chung, Beom Sun

    2018-01-01

    The authors have operated the homepage (http://anatomy.co.kr) to provide the learning contents of anatomy. From the homepage, sectioned images, volume models, and surface models—all Visible Korean products—can be downloaded. The realistic images can be interactively manipulated, which will give rise to the interest in anatomy. The various anatomy comics (learning comics, comic strips, plastination comics, etc.) are approachable. Visitors can obtain the regional anatomy book with concise contents, mnemonics, and schematics as well as the simplified dissection manual and the pleasant anatomy essay. Medical students, health allied professional students, and even laypeople are expected to utilize the easy and comforting anatomy contents. It is hoped that other anatomists successively produce and distribute their own informative contents. PMID:29644104

  9. Transparency of the municipal public management: a study from the homepages of the large Brazilian municipalities

    OpenAIRE

    Cruz, Cláudia Ferreira; Ferreira, Aracéli Cristina de Sousa; Silva, Lino Martins da; Macedo, Marcelo Álvaro da Silva

    2012-01-01

    This study attempts to check the transparency level of information in public administration published in the homepages of 96 municipalities included among the 100 most populous in Brazil and what characteristics and socioeconomic indicators of the municipalities can contribute to explain the level of transparency observed. The level of transparency in public administration was established from a research model called Transparency Index Municipal Public Management (ITGP-M) constructed based on...

  10. Measuring structural similarity in large online networks.

    Science.gov (United States)

    Shi, Yongren; Macy, Michael

    2016-09-01

    Structural similarity based on bipartite graphs can be used to detect meaningful communities, but the networks have been tiny compared to massive online networks. Scalability is important in applications involving tens of millions of individuals with highly skewed degree distributions. Simulation analysis holding underlying similarity constant shows that two widely used measures - Jaccard index and cosine similarity - are biased by the distribution of out-degree in web-scale networks. However, an alternative measure, the Standardized Co-incident Ratio (SCR), is unbiased. We apply SCR to members of Congress, musical artists, and professional sports teams to show how massive co-following on Twitter can be used to map meaningful affiliations among cultural entities, even in the absence of direct connections to one another. Our results show how structural similarity can be used to map cultural alignments and demonstrate the potential usefulness of social media data in the study of culture, politics, and organizations across the social and behavioral sciences. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Recruitment of prospective donors: what do they expect from a homepage of a blood transfusion service?

    Science.gov (United States)

    Moog, R; Fourné, K

    2007-08-01

    In times of shrinking donor population, the recruitment of donors is of utmost importance. Recruitment can be done by personal communication, advertisement/information, classical mass media (newspaper, radio, TV) or new computerized media. The aim of this study was to gain information about the donors' demands of an Internet presentation of a blood transfusion service. Between October and December 2004 inclusive, prospective donors were asked to complete a survey about the impact of Internet information for blood donors. The survey contained questions measuring demographics, education and motivation for blood donation. In addition, the survey included questions that measured Internet access, duration of online time and donors' demands for an Internet presentation of a blood transfusion service. Donors were asked to tick a box with predefined answers. In cases where no options were applied, donors were requested to specify their answers. One hundred and fourteen prospective donors (71 female, 43 male) with a median age of 25 years (range 18-57 years) completed the survey. Most donors (57.9%) were 18-30 years old. Forty-two (36.8%) of the surveyed donors were repeat donors, whereas 72 (63.2%) were first-time donors. The majority of donors were informed about blood donation from relatives or friends (70.7% repeat donors and 67.7% first-time donors). Most of them had Internet access (85.7% repeat donors and 90.3% first-time donors). Exclusive use of private access was more often reported in repeat donors (77.8%), whereas both private and professional access was more frequently used in first-time donors (32.3%). Most donors used the Internet access daily, followed by weekly and monthly use. Multiple answers were given about the importance of desired information about the topic 'blood donation'. Both first-time and repeat donors wanted to be informed about organizational details of blood donation such as opening times, eligibility criteria, donation process and the kind

  12. VPN (Virtual Private Network) Performance Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Calderon, Calixto; Goncalves, Joao G.M.; Sequeira, Vitor [Joint Research Centre, Ispra (Italy). Inst. for the Protection and Security of the Citizen; Vandaele, Roland; Meylemans, Paul [European Commission, DG-TREN (Luxembourg)

    2003-05-01

    Virtual Private Networks (VPN) is an important technology allowing for secure communications through insecure transmission media (i.e., Internet) by adding authentication and encryption to the existing protocols. This paper describes some VPN performance indicators measured over international communication links. An ISDN based VPN link was established between the Joint Research Centre, Ispra site, Italy, and EURATOM Safeguards in Luxembourg. This link connected two EURATOM Safeguards FAST surveillance stations, and used different vendor solutions hardware (Cisco router 1720 and Nokia CC-500 Gateway). To authenticate and secure this international link, we have used several methods at the different levels of the seven-layered ISO network protocol stack (i.e., Callback feature, CHAP - Challenge Handshake Protocol - authentication protocol). The tests made involved the use of different encryption algorithms and the way session secret keys are periodically renewed, considering these elements influence significantly the transmission throughput. Future tests will include the use of a wide variety of wireless media transmission and terminal equipment technologies, in particular PDAs (Personal Digital Assistants) and Notebook PCs. These tests aim at characterising the functionality of VPNs whenever field inspectors wish to contact headquarters to access information from a central archive database or transmit local measurements or documents. These technologies cover wireless transmission needs at different geographical scales: roombased level Bluetooth, floor or building level Wi-Fi and region or country level GPRS.

  13. Measuring the evolutionary rewiring of biological networks.

    Directory of Open Access Journals (Sweden)

    Chong Shou

    Full Text Available We have accumulated a large amount of biological network data and expect even more to come. Soon, we anticipate being able to compare many different biological networks as we commonly do for molecular sequences. It has long been believed that many of these networks change, or "rewire", at different rates. It is therefore important to develop a framework to quantify the differences between networks in a unified fashion. We developed such a formalism based on analogy to simple models of sequence evolution, and used it to conduct a systematic study of network rewiring on all the currently available biological networks. We found that, similar to sequences, biological networks show a decreased rate of change at large time divergences, because of saturation in potential substitutions. However, different types of biological networks consistently rewire at different rates. Using comparative genomics and proteomics data, we found a consistent ordering of the rewiring rates: transcription regulatory, phosphorylation regulatory, genetic interaction, miRNA regulatory, protein interaction, and metabolic pathway network, from fast to slow. This ordering was found in all comparisons we did of matched networks between organisms. To gain further intuition on network rewiring, we compared our observed rewirings with those obtained from simulation. We also investigated how readily our formalism could be mapped to other network contexts; in particular, we showed how it could be applied to analyze changes in a range of "commonplace" networks such as family trees, co-authorships and linux-kernel function dependencies.

  14. Homepage Coordination

    Science.gov (United States)

    Hodas, Steven

    1995-01-01

    This paper describes efforts to identify issues and design implementation strategies to better promote the NASA IITA K-12 project on the world wide web and, in so doing, better serve our constituents.

  15. Homepages of German dental schools - a target group-oriented evaluation.

    Science.gov (United States)

    Wehlers, A; Schäfer, I; Sehner, S; Kahl-Nieke, B; Kuhnigk, O

    2014-08-01

    The Internet represents the central communication medium in higher education. University applicants, students, teachers and scientists use the Internet when seeking information on medicine. The homepages of dental schools are not just sources of information, but also a means of presenting the school. No comparative studies have been undertaken concerning the content and extent of their Internet sites so far. Based on the literature and assessments of medical school websites, 136 criteria were defined within the setting of a Delphi procedure and drawn upon for a standardised evaluation of the websites of all 30 German dental schools. Structure and extent of the content of the websites were evaluated. Possible influencing factors, such as financial resources and number of applicants, were investigated. The results yielded by the homepages varied considerably. The best Internet site received 84% of the possible points, the poorest 38%. On average, 62% of the criteria were fulfilled. Influencing factors, such as the amount of funding by the particular state government, could not be detected. Two-thirds of the dental schools addressed students, three-fourth teachers and scientists as target groups. More than 50% did not address applicants. Specific requirements regarding barrier-free accessibility of information were hardly met. Individual faculties already have homepages of a high quality; for others, there is a need for improvement. General recommendations for university websites should be discussed at the European level to ensure a uniform standard of quality. The criteria presented here offer faculties the possibility to reflect upon their own Internet sites. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. [Preparation of the database and the homepage on chemical accidents relating to health hazard].

    Science.gov (United States)

    Yamamoto, M; Morita, M; Kaminuma, T

    1998-01-01

    We collected the data on accidents due to chemicals occurred in Japan, and prepared the database. We also set up the World Wide Web homepage containing the explanation on accidents due to chemicals and the retrieval page for the database. We designed the retrieval page so that users can search the data from keywords such as chemicals (e.g. chlorine gas, hydrogen sulfide, pesticides), places (e.g. home, factory, vehicles, tank), causes (e.g. reaction, leakage, exhaust gas) and others (e.g. cleaning, painting, transportation).

  17. [Preparation of the database and the Internet (WWW) homepage for regulations on chemicals in Japan].

    Science.gov (United States)

    Yamamoto, M; Morita, M; Kaminuma, T

    1999-01-01

    We prepared a database on chemical regulations in Japan. The regulations consist of "The Law concerning the Examination and Regulation of Manufacture, etc., of Chemical Substances", "Poisonous and Deleterious Substances", Control Law", "Waterworks Law", "Law for the Control of Household Products containing Harmful Substances", and Pesticide Residues in Food Sanitation Law". We also set up a World Wide Web (WWW) homepage containing an explanation of the law as well as chemical names, CAS registry numbers, and standards. The WWW pages contain lists of chemicals and the retrieval page for the database.

  18. Improving the Library Homepage through User Research — Without a Total Redesign

    OpenAIRE

    Amy Deschenes

    2014-01-01

    Conducting user research doesn't have to be difficult, time consuming, or expensive. Your Library website can be improved through user research even if you have design restrictions because of a prescribed branding scheme, content management system, or any other reason. At Simmons College in Boston, we recently performed a user research study that took an in-depth look at the content organization and wording of links on the Library homepage. We conducted an in-person paper survey using paper p...

  19. On Measuring the Complexity of Networks: Kolmogorov Complexity versus Entropy

    Directory of Open Access Journals (Sweden)

    Mikołaj Morzy

    2017-01-01

    Full Text Available One of the most popular methods of estimating the complexity of networks is to measure the entropy of network invariants, such as adjacency matrices or degree sequences. Unfortunately, entropy and all entropy-based information-theoretic measures have several vulnerabilities. These measures neither are independent of a particular representation of the network nor can capture the properties of the generative process, which produces the network. Instead, we advocate the use of the algorithmic entropy as the basis for complexity definition for networks. Algorithmic entropy (also known as Kolmogorov complexity or K-complexity for short evaluates the complexity of the description required for a lossless recreation of the network. This measure is not affected by a particular choice of network features and it does not depend on the method of network representation. We perform experiments on Shannon entropy and K-complexity for gradually evolving networks. The results of these experiments point to K-complexity as the more robust and reliable measure of network complexity. The original contribution of the paper includes the introduction of several new entropy-deceiving networks and the empirical comparison of entropy and K-complexity as fundamental quantities for constructing complexity measures for networks.

  20. Measuring the democratic anchorage of governance networks

    DEFF Research Database (Denmark)

    Fotel, Trine; Sørensen, Eva; Torfing, Jacob

    There has been a growing debate about the democratic problems and potentials of governance networks among political scientists and public managers. While some claim that governance networks tend to undermine democracy, others argue that they have the potential to improve and strengthen democracy....... This debate is found wanting in two respects. First of all, there has been far too little discussion about what democracy means in relation to pluricentric governance networks. Second, the current debate builds on the assumption that it is possible to give a clear-cut answer to the question of the democratic...... problems and merits of governance networks. This assumption is highly questionable, and prevents a more nuanced assessment of the democratic performance of governance networks. As such, it diverts the focus of attention away from the fact that governance networks may be democratic in some respects...

  1. CERN Public homepage takes its first step towards web 2.0

    CERN Multimedia

    2009-01-01

    Some of you may have noticed a change of format on the CERN public homepage recently. The Bulletin catches up with Dan Noyes, CERN web content manager, to find out what is happening. With over 7000 websites in the cern.ch domain, CERN’s web landscape is a challenging one to manage. Dan Noyes, who joined CERN a year ago, is the web content manager within the Communication group, which is mandated to develop the public and user websites as well as developing standards and guidelines for the wider CERN web. The recent changes made to the public homepage were the first small step towards some quite major changes proposed for CERN’s websites over the next couple of years. Currently, one of the problems of CERN’s websites is that the quantity and the diversity of the information in them make them difficult to manage, if one wants to avoid duplication and to keep information updated and easy to find. This is also aggravated by the lack of a standard design philosophy a...

  2. Measuring Asymmetry in Insect-Plant Networks

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Claudia P T [Programa de Pos-Graduacao em Fisica, Universidade Federal do Rio Grande do Norte, UFRN - Campus Universitario, Lagoa Nova, CEP 59078 972, Natal, RN (Brazil); De Almeida, Adriana M [Departamento de Botanica, Ecologia e Zoologia, Centro de Biociencias, Universidade Federal do Rio Grande do Norte, UFRN - Campus Universitario, Lagoa Nova, CEP 59078 972, Natal, RN (Brazil); Corso, Gilberto, E-mail: claudia@dfte.ufrn.br, E-mail: adrianam@ufrn.br, E-mail: corso@cb.ufrn.br [Departamento de Biofisica e Farmacologia, Centro de Biociencias, Universidade Federal do Rio Grande do Norte, UFRN - Campus Universitario, Lagoa Nova, CEP 59078 972, Natal, RN (Brazil)

    2011-03-01

    In this work we focus on interaction networks between insects and plants and in the characterization of insect plant asymmetry, an important issue in coevolution and evolutionary biology. We analyze in particular the asymmetry in the interaction matrix of animals (herbivorous insects) and plants (food resource for the insects). Instead of driving our attention to the interaction matrix itself we derive two networks associated to the bipartite network: the animal network, D{sub 1}, and the plant network, D{sub 2}. These networks are constructed according to the following recipe: two animal species are linked once if they interact with the same plant. In a similar way, in the plant network, two plants are linked if they interact with the same animal. To explore the asymmetry between D{sub 2} and D{sub 1} we test for a set of 23 networks from the ecologic literature networks: the difference in size, {Delta}L, clustering coefficient difference, {Delta}C, and mean connectivity difference, {Delta}. We used a nonparametric statistical test to check the differences in {Delta}L, {Delta}C and {Delta}. Our results indicate that {Delta}L and {Delta} show a significative asymmetry.

  3. Analyzing complex networks through correlations in centrality measurements

    International Nuclear Information System (INIS)

    Ricardo Furlan Ronqui, José; Travieso, Gonzalo

    2015-01-01

    Many real world systems can be expressed as complex networks of interconnected nodes. It is frequently important to be able to quantify the relative importance of the various nodes in the network, a task accomplished by defining some centrality measures, with different centrality definitions stressing different aspects of the network. It is interesting to know to what extent these different centrality definitions are related for different networks. In this work, we study the correlation between pairs of a set of centrality measures for different real world networks and two network models. We show that the centralities are in general correlated, but with stronger correlations for network models than for real networks. We also show that the strength of the correlation of each pair of centralities varies from network to network. Taking this fact into account, we propose the use of a centrality correlation profile, consisting of the values of the correlation coefficients between all pairs of centralities of interest, as a way to characterize networks. Using the yeast protein interaction network as an example we show also that the centrality correlation profile can be used to assess the adequacy of a network model as a representation of a given real network. (paper)

  4. Characterizations of the Beta and the Degree Network Power Measure

    NARCIS (Netherlands)

    van den Brink, J.R.; Borm, P.; Hendrickx, R.; Owen, G.

    2008-01-01

    A symmetric network consists of a set of positions and a set of bilateral links between these positions. For every symmetric network we define a cooperative transferable utility game that measures the "power" of each coalition of positions in the network. Applying the Shapley value to this game

  5. Multiple Social Networks, Data Models and Measures for

    DEFF Research Database (Denmark)

    Magnani, Matteo; Rossi, Luca

    2017-01-01

    Multiple Social Network Analysis is a discipline defining models, measures, methodologies, and algorithms to study multiple social networks together as a single social system. It is particularly valuable when the networks are interconnected, e.g., the same actors are present in more than one...

  6. Hyperbolicity measures democracy in real-world networks

    Science.gov (United States)

    Borassi, Michele; Chessa, Alessandro; Caldarelli, Guido

    2015-09-01

    In this work, we analyze the hyperbolicity of real-world networks, a geometric quantity that measures if a space is negatively curved. We provide two improvements in our understanding of this quantity: first of all, in our interpretation, a hyperbolic network is "aristocratic", since few elements "connect" the system, while a non-hyperbolic network has a more "democratic" structure with a larger number of crucial elements. The second contribution is the introduction of the average hyperbolicity of the neighbors of a given node. Through this definition, we outline an "influence area" for the vertices in the graph. We show that in real networks the influence area of the highest degree vertex is small in what we define "local" networks (i.e., social or peer-to-peer networks), and large in "global" networks (i.e., power grid, metabolic networks, or autonomous system networks).

  7. Representative Delay Measurements (RDM: Facing the Challenge of Modern Networks

    Directory of Open Access Journals (Sweden)

    Joachim Fabini

    2015-02-01

    Full Text Available Network access technologies have evolved significantly in the last years. They deploy novel mechanisms like reactive capacity allocation and time-slotted operation to optimize overall network capacity. From a single node's perspective, such optimizations decrease network determinism and measurement repeatability. Evolving application fields like machine to machine (M2M communications or real-time gaming often have strict real-time requirements to operate correctly. Highly accurate delay measurements are necessary to monitor network compliance with application demands or to detect deviations of normal network behavior, which may be caused by network failures, misconfigurations or attacks. This paper analyzes factors that challenge active delay measurements in modern networks. It introduces the Representative Delay Measurement tool (RDM that addresses these factors and proposes solutions that conform to requirements of the recently published RFC7312. Delay measurement results acquired using RDM in live networks confirm that advanced measurement methods can significantly improve the quality of measurement samples by isolating systematic network behavior. The resulting high-quality samples are one prerequisite for accurate statistics that support proper operation of subsequent algorithms and applications.

  8. Social network analysis of public health programs to measure partnership.

    Science.gov (United States)

    Schoen, Martin W; Moreland-Russell, Sarah; Prewitt, Kim; Carothers, Bobbi J

    2014-12-01

    In order to prevent chronic diseases, community-based programs are encouraged to take an ecological approach to public health promotion and involve many diverse partners. Little is known about measuring partnership in implementing public health strategies. We collected data from 23 Missouri communities in early 2012 that received funding from three separate programs to prevent obesity and/or reduce tobacco use. While all of these funding programs encourage partnership, only the Social Innovation for Missouri (SIM) program included a focus on building community capacity and enhancing collaboration. Social network analysis techniques were used to understand contact and collaboration networks in community organizations. Measurements of average degree, density, degree centralization, and betweenness centralization were calculated for each network. Because of the various sizes of the networks, we conducted comparative analyses with and without adjustment for network size. SIM programs had increased measurements of average degree for partner collaboration and larger networks. When controlling for network size, SIM groups had higher measures of network density and lower measures of degree centralization and betweenness centralization. SIM collaboration networks were more dense and less centralized, indicating increased partnership. The methods described in this paper can be used to compare partnership in community networks of various sizes. Further research is necessary to define causal mechanisms of partnership development and their relationship to public health outcomes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. National network of environment radioactivity measurements. Press kit

    International Nuclear Information System (INIS)

    2010-01-01

    This document first presents the objectives, challenges, context, operation and actors of the French national network of environment radioactivity measurements. It discusses the reasons for these measurements, the way they are performed, who perform them and how they are transmitted to the national network. It describes the quality policy for these measurements, and how this network is at the service of authorities, experts and population. It outlines the originality of the French approach within the European Union, and how this network takes the population expectations and their evolution into account

  10. NASA GSFC Tin Whisker Homepage http://nepp.nasa.gov/whisker

    Science.gov (United States)

    Shaw, Harry

    2000-01-01

    The NASA GSFC Tin Whisker Homepage provides general information and GSFC Code 562 experimentation results regarding the well known phenomenon of tin whisker formation from pure tin plated substrates. The objective of this www site is to provide a central repository for information pertaining to this phenomenon and to provide status of the GSFC experiments to understand the behavior of tin whiskers in space environments. The Tin Whisker www site is produced by Code 562. This www site does not provide information pertaining to patented or proprietary information. All of the information contained in this www site is at the level of that produced by industry and university researchers and is published at international conferences.

  11. Displacement and deformation measurement for large structures by camera network

    Science.gov (United States)

    Shang, Yang; Yu, Qifeng; Yang, Zhen; Xu, Zhiqiang; Zhang, Xiaohu

    2014-03-01

    A displacement and deformation measurement method for large structures by a series-parallel connection camera network is presented. By taking the dynamic monitoring of a large-scale crane in lifting operation as an example, a series-parallel connection camera network is designed, and the displacement and deformation measurement method by using this series-parallel connection camera network is studied. The movement range of the crane body is small, and that of the crane arm is large. The displacement of the crane body, the displacement of the crane arm relative to the body and the deformation of the arm are measured. Compared with a pure series or parallel connection camera network, the designed series-parallel connection camera network can be used to measure not only the movement and displacement of a large structure but also the relative movement and deformation of some interesting parts of the large structure by a relatively simple optical measurement system.

  12. A complex network-based importance measure for mechatronics systems

    Science.gov (United States)

    Wang, Yanhui; Bi, Lifeng; Lin, Shuai; Li, Man; Shi, Hao

    2017-01-01

    In view of the negative impact of functional dependency, this paper attempts to provide an alternative importance measure called Improved-PageRank (IPR) for measuring the importance of components in mechatronics systems. IPR is a meaningful extension of the centrality measures in complex network, which considers usage reliability of components and functional dependency between components to increase importance measures usefulness. Our work makes two important contributions. First, this paper integrates the literature of mechatronic architecture and complex networks theory to define component network. Second, based on the notion of component network, a meaningful IPR is brought into the identifying of important components. In addition, the IPR component importance measures, and an algorithm to perform stochastic ordering of components due to the time-varying nature of usage reliability of components and functional dependency between components, are illustrated with a component network of bogie system that consists of 27 components.

  13. Network Skewness Measures Resilience in Lake Ecosystems

    Science.gov (United States)

    Langdon, P. G.; Wang, R.; Dearing, J.; Zhang, E.; Doncaster, P.; Yang, X.; Yang, H.; Dong, X.; Hu, Z.; Xu, M.; Yanjie, Z.; Shen, J.

    2017-12-01

    Changes in ecosystem resilience defy straightforward quantification from biodiversity metrics, which ignore influences of community structure. Naturally self-organized network structures show positive skewness in the distribution of node connections. Here we test for skewness reduction in lake diatom communities facing anthropogenic stressors, across a network of 273 lakes in China containing 452 diatom species. Species connections show positively skewed distributions in little-impacted lakes, switching to negative skewness in lakes associated with human settlement, surrounding land-use change, and higher phosphorus concentration. Dated sediment cores reveal a down-shifting of network skewness as human impacts intensify, and reversal with recovery from disturbance. The appearance and degree of negative skew presents a new diagnostic for quantifying system resilience and impacts from exogenous forcing on ecosystem communities.

  14. HOMEPAGE: UM MATERIAL EDUCACIONAL DIGITAL NA APRENDIZAGEM DE INGLÊS

    Directory of Open Access Journals (Sweden)

    Marcus de Souza ARAÚJO

    2017-07-01

    Full Text Available Este artigo tem como objetivo relatar uma atividade de produção escrita em inglês dos gêneros discursivos apresentação pessoal e homepage no contexto acadêmico. O estudo se desenvolve por meio de referenciais teóricos da perspectiva do material didático (DUDLEY EVANS; ST. JOHN, 1998; GRAVES, 2000; RAMOS, 2009; entre outros, da escrita como processo (BROWN, 2004; DIAS, 2004; FIGUEIREDO, 2005 e de contribuições da tecnologia digital no ensino de línguas (PRENSKY, 2012; ROJO, 2012; entre outros.  A atividade relatada levou em consideração a abordagem da escrita como processo, ou seja, geração e estruturação das ideias, rascunho, avaliação, revisão, correção em pares, edição.  Pensando no compartilhamento das produções escritas dos alunos, o resultado final da atividade foi a criação coletiva de uma homepage para a publicação do gênero apresentação pessoal, além de postagens de vídeos e sugestões de sites e outros links. Os resultados da pesquisa apontam aumento na motivação dos alunos em processo de formação inicial para produzir gêneros escritos a partir das tecnologias digitais.

  15. Measuring interoperability maturity in government networks.

    NARCIS (Netherlands)

    Huijsman, K.L.L.G.; Plomp, M.G.A.; Batenburg, R.S.

    2012-01-01

    The purpose of this paper is to create a model that describes the development of interorganisational collaboration in government networks that apply eGovernment. Contrary to several models that describe eGovernment from a government-to-citizen perspective, and primarily emphasise on the front office

  16. Measuring interoperability maturity in government networks

    NARCIS (Netherlands)

    Huijsman, K.L.L.G; Plomp, M.G.A.; Batenburg, R.S.

    2012-01-01

    The purpose of this paper is to create a model that describes the development of interorganisational collaboration in government networks that apply eGovernment. Contrary to several models that describe eGovernment from a government-to-citizen perspective, and primarily emphasise on the front office

  17. Building and measuring a high performance network architecture

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, William T.C.; Toole, Timothy; Fisher, Chuck; Dugan, Jon; Wheeler, David; Wing, William R; Nickless, William; Goddard, Gregory; Corbato, Steven; Love, E. Paul; Daspit, Paul; Edwards, Hal; Mercer, Linden; Koester, David; Decina, Basil; Dart, Eli; Paul Reisinger, Paul; Kurihara, Riki; Zekauskas, Matthew J; Plesset, Eric; Wulf, Julie; Luce, Douglas; Rogers, James; Duncan, Rex; Mauth, Jeffery

    2001-04-20

    Once a year, the SC conferences present a unique opportunity to create and build one of the most complex and highest performance networks in the world. At SC2000, large-scale and complex local and wide area networking connections were demonstrated, including large-scale distributed applications running on different architectures. This project was designed to use the unique opportunity presented at SC2000 to create a testbed network environment and then use that network to demonstrate and evaluate high performance computational and communication applications. This testbed was designed to incorporate many interoperable systems and services and was designed for measurement from the very beginning. The end results were key insights into how to use novel, high performance networking technologies and to accumulate measurements that will give insights into the networks of the future.

  18. Processing horizontal networks measured by integrated terrestrial and GPS technologies

    Directory of Open Access Journals (Sweden)

    Vincent Jakub

    2003-09-01

    Full Text Available Local horizontal networks in which GPS and terrestrial measurements (TER are done are often established at present. Iin other networks, the previous terrestrial measurements can be completed with quantities from contemporary GPS observations (tunnel nets, mining nets with surface and underground parts and other long-shaped nets.The processing of such heterobeneous (GPS, TER networks whose terrestrial measurements are performed as point coordinate measurements (∆X, ∆Y using (geodetic total stationIn is presented in this paper. In such network structures it is then available:- the values ∆X, ∆Y from TER observations which are transformed in the plane of S-JTSK for adjustement,- the values ∆X, ∆Y in the plane S-JTSK that can be obtained by 3D transformation of WGS84 netpoint coordinates from GPS observations to corresponding coordinates S-JTSK.For common adjusting all the ∆X, ∆Y, some elements of the network geometry (e.g. distances should be measured by both methods (GPS, TER. This approach makes possible an effective homogenisation of both network parts what is equivalent to saying that an expressive influence reduction on local frame realizations of S-JTSK in the whole network can be made.Results of network processing obtained in proposed manner are acceptable in general and they are equivalent (accuracy, reliability to results of another processing methods.

  19. Measurements and analysis of online social networks

    OpenAIRE

    González Sánchez, Roberto

    2014-01-01

    Mención Internacional Online Social Networks (OSNs) have become the most used Internet applications attracting hundreds of millions active users every day. The large amount of valuable information in OSNs (not even before available) has attracted the research community to design sophisticated techniques to collect, process, interpret and apply these data into a large range of disciplines including Sociology, Marketing, Computer Science, etc. This thesis presents a series of ...

  20. Measuring interoperability maturity in government networks.

    OpenAIRE

    Huijsman, K.L.L.G.; Plomp, M.G.A.; Batenburg, R.S.

    2012-01-01

    The purpose of this paper is to create a model that describes the development of interorganisational collaboration in government networks that apply eGovernment. Contrary to several models that describe eGovernment from a government-to-citizen perspective, and primarily emphasise on the front office of eGovernment services, this paper focuses on the collaboration that takes place in the back office to enable successful eGovernment services. A maturity model was developed to describe and asses...

  1. A method of reconstructing the spatial measurement network by mobile measurement transmitter for shipbuilding

    International Nuclear Information System (INIS)

    Guo, Siyang; Lin, Jiarui; Yang, Linghui; Ren, Yongjie; Guo, Yin

    2017-01-01

    The workshop Measurement Position System (wMPS) is a distributed measurement system which is suitable for the large-scale metrology. However, there are some inevitable measurement problems in the shipbuilding industry, such as the restriction by obstacles and limited measurement range. To deal with these factors, this paper presents a method of reconstructing the spatial measurement network by mobile transmitter. A high-precision coordinate control network with more than six target points is established. The mobile measuring transmitter can be added into the measurement network using this coordinate control network with the spatial resection method. This method reconstructs the measurement network and broadens the measurement scope efficiently. To verify this method, two comparison experiments are designed with the laser tracker as the reference. The results demonstrate that the accuracy of point-to-point length is better than 0.4mm and the accuracy of coordinate measurement is better than 0.6mm. (paper)

  2. Template measurement for plutonium pit based on neural networks

    International Nuclear Information System (INIS)

    Zhang Changfan; Gong Jian; Liu Suping; Hu Guangchun; Xiang Yongchun

    2012-01-01

    Template measurement for plutonium pit extracts characteristic data from-ray spectrum and the neutron counts emitted by plutonium. The characteristic data of the suspicious object are compared with data of the declared plutonium pit to verify if they are of the same type. In this paper, neural networks are enhanced as the comparison algorithm for template measurement of plutonium pit. Two kinds of neural networks are created, i.e. the BP and LVQ neural networks. They are applied in different aspects for the template measurement and identification. BP neural network is used for classification for different types of plutonium pits, which is often used for management of nuclear materials. LVQ neural network is used for comparison of inspected objects to the declared one, which is usually applied in the field of nuclear disarmament and verification. (authors)

  3. Resiliency as a component importance measure in network reliability

    International Nuclear Information System (INIS)

    Whitson, John C.; Ramirez-Marquez, Jose Emmanuel

    2009-01-01

    This paper seeks to define the concept of resiliency as a component importance measure related to network reliability. Resiliency can be defined as a composite of: (1) the ability of a network to provide service despite external failures and (2) the time to restore service when in the presence of such failures. Although, Resiliency has been extensively studied in different research areas, this paper will study the specific aspects of quantifiable network resiliency when the network is experiencing potential catastrophic failures from external events and/or influences, and when it is not known a priori which specific components within the network will fail. A formal definition for Category I resiliency is proposed and a step-by-step approach based on Monte-Carlo simulation to calculate it is defined. To illustrate the approach, two-terminal networks with varying degrees of redundancy, have been considered. The results obtained for test networks show that this new quantifiable concept of resiliency provides insight into the performance and topology of the network. Future use for this work could include methods for safeguarding critical network components and optimizing the use of redundancy as a technique to improve network resiliency.

  4. Vector network analyzer (VNA) measurements and uncertainty assessment

    CERN Document Server

    Shoaib, Nosherwan

    2017-01-01

    This book describes vector network analyzer measurements and uncertainty assessments, particularly in waveguide test-set environments, in order to establish their compatibility to the International System of Units (SI) for accurate and reliable characterization of communication networks. It proposes a fully analytical approach to measurement uncertainty evaluation, while also highlighting the interaction and the linear propagation of different uncertainty sources to compute the final uncertainties associated with the measurements. The book subsequently discusses the dimensional characterization of waveguide standards and the quality of the vector network analyzer (VNA) calibration techniques. The book concludes with an in-depth description of the novel verification artefacts used to assess the performance of the VNAs. It offers a comprehensive reference guide for beginners to experts, in both academia and industry, whose work involves the field of network analysis, instrumentation and measurements.

  5. A New Resilience Measure for Supply Chain Networks

    Directory of Open Access Journals (Sweden)

    Ruiying Li

    2017-01-01

    Full Text Available Currently, supply chain networks can span the whole world, and any disruption of these networks may cause economic losses, decreases in sales and unsustainable supplies. Resilience, the ability of the system to withstand disruption and return to a normal state quickly, has become a new challenge during the supply chain network design. This paper defines a new resilience measure as the ratio of the integral of the normalized system performance within its maximum allowable recovery time after the disruption to the integral of the performance in the normal state. Using the maximum allowable recovery time of the system as the time interval under consideration, this measure allows the resilience of different systems to be compared on the same relative scale, and be used under both scenarios that the system can or cannot restore in the given time. Two specific resilience measures, the resilience based on the amount of product delivered and the resilience based on the average delivery distance, are provided for supply chain networks. To estimate the resilience of a given supply chain network, a resilience simulation method is proposed based on the Monte Carlo method. A four-layered hierarchial mobile phone supply chain network is used to illustrate the resilience quantification process and show how network structure affects the resilience of supply chain networks.

  6. Transaction costs and social networks in productivity measurement

    DEFF Research Database (Denmark)

    Henningsen, Geraldine; Henningsen, Arne; Henning, Christian H. C. A.

    2015-01-01

    . Hence, both the absolute productivity measures and, more importantly, the productivity ranking will be distorted. A major driver of transaction costs is poor access to information and contract enforcement assistance. Social networks often catalyse information exchange as well as generate trust...... and support. Hence, we use measures of a firm’s access to social networks as a proxy for the transaction costs the firm faces. We develop a microeconomic production model that takes into account transaction costs and networks. Using a data set of 384 Polish farms, we empirically estimate this model...... and compare different parametric, semiparametric, and nonparametric model specifications. Our results generally support our hypothesis. Especially, large trading networks and dense household networks have a positive influence on a farm’s productivity. Furthermore, our results indicate that transaction costs...

  7. AmeriFlux Measurement Network: Science Team Research

    Energy Technology Data Exchange (ETDEWEB)

    Law, B E

    2012-12-12

    Research involves analysis and field direction of AmeriFlux operations, and the PI provides scientific leadership of the AmeriFlux network. Activities include the coordination and quality assurance of measurements across AmeriFlux network sites, synthesis of results across the network, organizing and supporting the annual Science Team Meeting, and communicating AmeriFlux results to the scientific community and other users. Objectives of measurement research include (i) coordination of flux and biometric measurement protocols (ii) timely data delivery to the Carbon Dioxide Information and Analysis Center (CDIAC); and (iii) assurance of data quality of flux and ecosystem measurements contributed by AmeriFlux sites. Objectives of integration and synthesis activities include (i) integration of site data into network-wide synthesis products; and (ii) participation in the analysis, modeling and interpretation of network data products. Communications objectives include (i) organizing an annual meeting of AmeriFlux investigators for reporting annual flux measurements and exchanging scientific information on ecosystem carbon budgets; (ii) developing focused topics for analysis and publication; and (iii) developing data reporting protocols in support of AmeriFlux network goals.

  8. Radiation therapy and internet - what can patients expect? homepage analysis of german radiotherapy institutions.

    Science.gov (United States)

    Janssen, Stefan; Meyer, Andreas; Vordermark, Dirk; Steinmann, Diana

    2010-12-01

    the internet as a source of medical information has emerged during the last years. There is a confusing amount of medical websites with a great diversity of quality. Websites of radiotherapy institutions could offer a safe and an easy-to-control way to assist patients' requests. 205 internet appearances of German radiotherapy institutions were analyzed in June 2009 (nonuniversity hospitals n = 108, medical practices n = 62, university hospitals n = 35). For the evaluation of each homepage verifiable criteria concerning basic information, service and medical issues were used. the quality of information published via internet by different radiotherapy institutions showed a large variety. Basic information like telephone numbers, operating hours, and direction guidance were provided in 96.7%, 40%, and 50.7%, respectively. 85% of the websites introduced the staff, 50.2% supplied photos and 14% further information on the attending physicians. The mean amount of continuative links to other websites was 5.4, the mean amount of articles supplying medical information for patients summed up to 4.6. Medical practices and university hospitals had statistically significant more informative articles and links to other websites than nonuniversity hospitals. No statistically significant differences could be found in most other categories like service issues and basic information. internet presences of radiotherapy institutions hold the chance to supply patients with professional and individualized medical information. While some websites are already using this opportunity, others show a lack of basic information or of user-friendliness.

  9. Tariffing of energy measured consumers in the distribution network

    International Nuclear Information System (INIS)

    2006-01-01

    Criteria for socio-economic effective tariffing of energy-measured clients in the distribution network are discussed (i.e. households, leisure homes and smaller business clients), this means consumers that do not have hourly measurements or effect measurements. The tariffs should be based on variable segments that reflect short-term marginal costs in the network (in practice loss of transfer) and fixed segments that to the least extent possible influence the consumers' decisions in the choice of energy solutions, both in short term and long term. High-priced energy segments and effect based fixed segments may give unfortunate socio-economic price signals compared to the marginal long-term network costs. A fixed segment per measurement unit is in principle completely neutral, but it is to some extent vulnerable to strategic adjustments if the consumers choose collective measurement. This is not necessarily a big problem in practice (author)

  10. Information loss method to measure node similarity in networks

    Science.gov (United States)

    Li, Yongli; Luo, Peng; Wu, Chong

    2014-09-01

    Similarity measurement for the network node has been paid increasing attention in the field of statistical physics. In this paper, we propose an entropy-based information loss method to measure the node similarity. The whole model is established based on this idea that less information loss is caused by seeing two more similar nodes as the same. The proposed new method has relatively low algorithm complexity, making it less time-consuming and more efficient to deal with the large scale real-world network. In order to clarify its availability and accuracy, this new approach was compared with some other selected approaches on two artificial examples and synthetic networks. Furthermore, the proposed method is also successfully applied to predict the network evolution and predict the unknown nodes' attributions in the two application examples.

  11. Measuring network competence in buyer-supplier relationships

    Directory of Open Access Journals (Sweden)

    Gert Human

    2011-04-01

    Full Text Available Managing multiple buyer-seller relationships in business-to-business networks demands an understanding of a firm’s competence to manage in an interconnected environment.  This paper reports on an attempt to measure network competence by using the NetCompTest scale in business-to-business markets in South Africa. Based on a pilot study refinement, the paper proposes an adjusted measurement scale and details the results of a second round of measurement conducted amongst 495 business-to-business managers in South Africa. The results established partial support for the use of the NetCompTest scale in a South African context, and analysis of variance indicated that some differences in the measurement based on firm and individual characteristics can be observed in the data. The paper assists in theory-building and provides managerial insights for managing buyer-supplier relationships in networks.

  12. Time Synchronized Wireless Sensor Network for Vibration Measurement

    Science.gov (United States)

    Uchimura, Yutaka; Nasu, Tadashi; Takahashi, Motoichi

    Network based wireless sensing has become an important area of research and various new applications for remote sensing are expected to emerge. One of the promising applications is structural health monitoring of building or civil engineering structure and it often requires vibration measurement. For the vibration measurement via wireless network, time synchronization is indispensable. In this paper, we introduce a newly developed time synchronized wireless sensor network system. The system employs IEEE 802.11 standard based TSF counter and sends the measured data with the counter value. TSF based synchronization enables consistency on common clock among different wireless nodes. We consider the scale effect on the synchronization accuracy and the effect is evaluated by stochastic analysis and simulation studies. A new wireless sensing system is developed and the hardware and software specifications are shown. The experiments are conducted in a reinforced concrete building and results show good performance enough for vibration measurement purpose.

  13. Link-quality measurement and reporting in wireless sensor networks.

    Science.gov (United States)

    Chehri, Abdellah; Jeon, Gwanggil; Choi, Byoungjo

    2013-03-04

    Wireless Sensor networks (WSNs) are created by small hardware devices that possess the necessary functionalities to measure and exchange a variety of environmental data in their deployment setting. In this paper, we discuss the experiments in deploying a testbed as a first step towards creating a fully functional heterogeneous wireless network-based underground monitoring system. The system is mainly composed of mobile and static ZigBee nodes, which are deployed on the underground mine galleries for measuring ambient temperature. In addition, we describe the measured results of link characteristics such as received signal strength, latency and throughput for different scenarios.

  14. Link-Quality Measurement and Reporting in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Byoungjo Choi

    2013-03-01

    Full Text Available Wireless Sensor networks (WSNs are created by small hardware devices that possess the necessary functionalities to measure and exchange a variety of environmental data in their deployment setting. In this paper, we discuss the experiments in deploying a testbed as a first step towards creating a fully functional heterogeneous wireless network-based underground monitoring system. The system is mainly composed of mobile and static ZigBee nodes, which are deployed on the underground mine galleries for measuring ambient temperature. In addition, we describe the measured results of link characteristics such as received signal strength, latency and throughput for different scenarios.

  15. A working group for Japanese nuclear data measurement network

    International Nuclear Information System (INIS)

    Watanabe, Yukinobu

    2013-01-01

    A new working group in the Japanese Nuclear Data Committee has been established to make a cooperative network among researchers involved in nuclear data measurements and to discuss the strategy for nuclear data measurements. The working group activities are reported. (author)

  16. Arrester Resistive Current Measuring System Based on Heterogeneous Network

    Science.gov (United States)

    Zhang, Yun Hua; Li, Zai Lin; Yuan, Feng; Hou Pan, Feng; Guo, Zhan Nan; Han, Yue

    2018-03-01

    Metal Oxide Arrester (MOA) suffers from aging and poor insulation due to long-term impulse voltage and environmental impact, and the value and variation tendency of resistive current can reflect the health conditions of MOA. The common wired MOA detection need to use long cables, which is complicated to operate, and that wireless measurement methods are facing the problems of poor data synchronization and instability. Therefore a novel synchronous measurement system of arrester current resistive based on heterogeneous network is proposed, which simplifies the calculation process and improves synchronization, accuracy and stability and of the measuring system. This system combines LoRa wireless network, high speed wireless personal area network and the process layer communication, and realizes the detection of arrester working condition. Field test data shows that the system has the characteristics of high accuracy, strong anti-interference ability and good synchronization, which plays an important role in ensuring the stable operation of the power grid.

  17. Transaction costs and social networks in productivity measurement

    DEFF Research Database (Denmark)

    Henningsen, Geraldine; Henningsen, Arne; Henning, Christian H. C. A.

    2015-01-01

    and support. Hence, we use measures of a firm’s access to social networks as a proxy for the transaction costs the firm faces. We develop a microeconomic production model that takes into account transaction costs and networks. Using a data set of 384 Polish farms, we empirically estimate this model......We argue that in the presence of transaction costs, observed productivity measures may in many cases understate the true productivity, as production data seldom distinguish between resources entering the production process and resources of a similar type that are sacrificed for transaction costs....... Hence, both the absolute productivity measures and, more importantly, the productivity ranking will be distorted. A major driver of transaction costs is poor access to information and contract enforcement assistance. Social networks often catalyse information exchange as well as generate trust...

  18. Pathloss Measurements and Modeling for UAVs Connected to Cellular Networks

    DEFF Research Database (Denmark)

    Amorim, Rafhael Medeiros de; Mogensen, Preben Elgaard; Sørensen, Troels Bundgaard

    2017-01-01

    . The measurements were conducted in an operating LTE network (850 MHz), using a commercial cell phone, placed inside the frame of the UAV. Trials were conducted for UAV flying at 5 different heights measured above ground level (20, 40, 60, 80 and 100m) and a pathloss regression line was obtained from results. Then......This paper assess field measurements, as part of the investigation of the suitability of cellular networks for providing connectivity to UAVs (unmanned aerial vehicles). Evaluation is done by means of field measurements obtained in a rural environment in Denmark with an airbone UAV......, downlink (DL) SINR levels obtained during flight measurements are also presented. An important result obtained from the measurents reveal that there is a height-related DL SINR degradation. Three main sources of uncertainty on the pathloss model that could be responsible for the SINR degradation are also...

  19. The new challenges of multiplex networks: Measures and models

    Science.gov (United States)

    Battiston, Federico; Nicosia, Vincenzo; Latora, Vito

    2017-02-01

    What do societies, the Internet, and the human brain have in common? They are all examples of complex relational systems, whose emerging behaviours are largely determined by the non-trivial networks of interactions among their constituents, namely individuals, computers, or neurons, rather than only by the properties of the units themselves. In the last two decades, network scientists have proposed models of increasing complexity to better understand real-world systems. Only recently we have realised that multiplexity, i.e. the coexistence of several types of interactions among the constituents of a complex system, is responsible for substantial qualitative and quantitative differences in the type and variety of behaviours that a complex system can exhibit. As a consequence, multilayer and multiplex networks have become a hot topic in complexity science. Here we provide an overview of some of the measures proposed so far to characterise the structure of multiplex networks, and a selection of models aiming at reproducing those structural properties and quantifying their statistical significance. Focusing on a subset of relevant topics, this brief review is a quite comprehensive introduction to the most basic tools for the analysis of multiplex networks observed in the real-world. The wide applicability of multiplex networks as a framework to model complex systems in different fields, from biology to social sciences, and the colloquial tone of the paper will make it an interesting read for researchers working on both theoretical and experimental analysis of networked systems.

  20. Use of artificial neural networks on optical track width measurements

    Science.gov (United States)

    Smith, Richard J.; See, Chung W.; Somekh, Mike G.; Yacoot, Andrew

    2007-08-01

    We have demonstrated recently that, by using an ultrastable optical interferometer together with artificial neural networks (ANNs), track widths down to 60 nm can be measured with a 0.3 NA objective lens. We investigate the effective conditions for training ANNs. Experimental results will be used to show the characteristics of the training samples and the data format of the ANN inputs required to produce suitably trained ANNs. Results obtained with networks measuring double tracks, and classifying different structures, will be presented to illustrate the capability of the technique. We include a discussion on expansion of the application areas of the system, allowing it to be used as a general purpose instrument.

  1. THE MEASUREMENT ELECTROMAGNETIC INTERFERENCE IN THE REVERSE TRACTION NETWORK

    Directory of Open Access Journals (Sweden)

    T. M. Serdiuk

    2009-09-01

    Full Text Available The original automated method of measurement of electrical noise in the return electric-traction network is proposed. It is realized on the base of car-laboratory “Automatics, telemechanics and communication”. The mathematic model of return electric-traction network is developed to scientific bases of automated measurement. It allows us obtaining the mathematic expressions for change of voltage and current harmonics in the rail net and taking into account the inhomogeneity of lines for the following analytic determination of a source of electric noise.

  2. Network measurements at the heavy ion synchrotron SIS at GSI

    International Nuclear Information System (INIS)

    Vossbeck, P.; Pschorn, I.; Gebhard, Moritz

    1999-01-01

    The Heavy Ion Synchrotron SIS forms together with the Linear Accelerator UNILAC and the Storage Ring ESR the accelerator complex of the Gesellschaft fuer Schwerionenforschung in Darmstadt. It accelerates heavy ions up to Uranium to 1 GeV/amu. The accelerators and beamlines have been surveyed and aligned using the TASA method. For SIS a network was established in order to survey the synchrotron with the TASA method. Goal of a diploma thesis was to establish an alternative network for a Laser Tracker instrument and to reach error ellipsoids below 30 μm. In this paper a comparison of the two methods is given. Since the Tracker measurements are done automatically only one person is needed. That reduces the man power. Time consumption for both methods is about the same, although much more network points were used with the Laser Tracker method. As a consequence of the larger number of network points the homogeneity of the results is better. (authors)

  3. Measuring Networking as an Outcome Variable in Undergraduate Research Experiences.

    Science.gov (United States)

    Hanauer, David I; Hatfull, Graham

    2015-01-01

    The aim of this paper is to propose, present, and validate a simple survey instrument to measure student conversational networking. The tool consists of five items that cover personal and professional social networks, and its basic principle is the self-reporting of degrees of conversation, with a range of specific discussion partners. The networking instrument was validated in three studies. The basic psychometric characteristics of the scales were established by conducting a factor analysis and evaluating internal consistency using Cronbach's alpha. The second study used a known-groups comparison and involved comparing outcomes for networking scales between two different undergraduate laboratory courses (one involving a specific effort to enhance networking). The final study looked at potential relationships between specific networking items and the established psychosocial variable of project ownership through a series of binary logistic regressions. Overall, the data from the three studies indicate that the networking scales have high internal consistency (α = 0.88), consist of a unitary dimension, can significantly differentiate between research experiences with low and high networking designs, and are related to project ownership scales. The ramifications of the networking instrument for student retention, the enhancement of public scientific literacy, and the differentiation of laboratory courses are discussed. © 2015 D. I. Hanauer and G. Hatfull. CBE—Life Sciences Education © 2015 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  4. Centrality measures and thermodynamic formalism for complex networks.

    Science.gov (United States)

    Delvenne, Jean-Charles; Libert, Anne-Sophie

    2011-04-01

    In the study of small and large networks it is customary to perform a simple random walk where the random walker jumps from one node to one of its neighbors with uniform probability. The properties of this random walk are intimately related to the combinatorial properties of the network. In this paper we propose to use the Ruelle-Bowens random walk instead, whose probability transitions are chosen in order to maximize the entropy rate of the walk on an unweighted graph. If the graph is weighted, then a free energy is optimized instead of the entropy rate. Specifically, we introduce a centrality measure for large networks, which is the stationary distribution attained by the Ruelle-Bowens random walk; we name it entropy rank. We introduce a more general version, which is able to deal with disconnected networks, under the name of free-energy rank. We compare the properties of those centrality measures with the classic PageRank and hyperlink-induced topic search (HITS) on both toy and real-life examples, in particular their robustness to small modifications of the network. We show that our centrality measures are more discriminating than PageRank, since they are able to distinguish clearly pages that PageRank regards as almost equally interesting, and are more sensitive to the medium-scale details of the graph.

  5. Combined techniques for network measurements at accelerator facilities

    International Nuclear Information System (INIS)

    Pschorn, I.

    1999-01-01

    Usually network measurements at GSi (Gesellschaft fur Schwerionen forschung) are carried out by employing the Leica tachymeter TC2002K etc. Due to time constraints and the fact that GSi possesses only one of these selected, high precision total-stations, it was suddenly necessary to think about employing a Laser tracker as the major instrument for a reference network measurement. The idea was to compare the different instruments and to proof if it is possible at all to carry out a precise network measurement using a laser tracker. In the end the SMX Tracker4500 combined with Leica NA3000 for network measurements at GSi, Darmstadt and at BESSY Il, Berlin (both located in Germany) was applied. A few results are shown in the following chapters. A new technology in 3D metrology came up. Some ideas of applying these new tools in the field of accelerator measurements are given. Finally aspects of calibration and checking the performance of the employed high precision instrument are pointed out in this paper. (author)

  6. EIGENVECTOR-BASED CENTRALITY MEASURES FOR TEMPORAL NETWORKS*

    Science.gov (United States)

    TAYLOR, DANE; MYERS, SEAN A.; CLAUSET, AARON; PORTER, MASON A.; MUCHA, PETER J.

    2017-01-01

    Numerous centrality measures have been developed to quantify the importances of nodes in time-independent networks, and many of them can be expressed as the leading eigenvector of some matrix. With the increasing availability of network data that changes in time, it is important to extend such eigenvector-based centrality measures to time-dependent networks. In this paper, we introduce a principled generalization of network centrality measures that is valid for any eigenvector-based centrality. We consider a temporal network with N nodes as a sequence of T layers that describe the network during different time windows, and we couple centrality matrices for the layers into a supra-centrality matrix of size NT × NT whose dominant eigenvector gives the centrality of each node i at each time t. We refer to this eigenvector and its components as a joint centrality, as it reflects the importances of both the node i and the time layer t. We also introduce the concepts of marginal and conditional centralities, which facilitate the study of centrality trajectories over time. We find that the strength of coupling between layers is important for determining multiscale properties of centrality, such as localization phenomena and the time scale of centrality changes. In the strong-coupling regime, we derive expressions for time-averaged centralities, which are given by the zeroth-order terms of a singular perturbation expansion. We also study first-order terms to obtain first-order-mover scores, which concisely describe the magnitude of nodes’ centrality changes over time. As examples, we apply our method to three empirical temporal networks: the United States Ph.D. exchange in mathematics, costarring relationships among top-billed actors during the Golden Age of Hollywood, and citations of decisions from the United States Supreme Court. PMID:29046619

  7. Evaluating airline energy efficiency: An integrated approach with Network Epsilon-based Measure and Network Slacks-based Measure

    International Nuclear Information System (INIS)

    Xu, Xin; Cui, Qiang

    2017-01-01

    This paper focuses on evaluating airline energy efficiency, which is firstly divided into four stages: Operations Stage, Fleet Maintenance Stage, Services Stage and Sales Stage. The new four-stage network structure of airline energy efficiency is a modification of existing models. A new approach, integrated with Network Epsilon-based Measure and Network Slacks-based Measure, is applied to assess the overall energy efficiency and divisional efficiency of 19 international airlines from 2008 to 2014. The influencing factors of airline energy efficiency are analyzed through the regression analysis. The results indicate the followings: 1. The integrated model can identify the benchmarking airlines in the overall system and stages. 2. Most airlines' energy efficiencies keep steady during the period, except for some sharply fluctuations. The efficiency decreases mainly centralized in the year 2008–2011, affected by the financial crisis in the USA. 3. The average age of fleet is positively correlated with the overall energy efficiency, and each divisional efficiency has different significant influencing factors. - Highlights: • An integrated approach with Network Epsilon-based Measure and Network Slacks-based Measure is developed. • 19 airlines' energy efficiencies are evaluated. • Garuda Indonesia has the highest overall energy efficiency.

  8. The French National Network for the Measurement of Environmental Radioactivity

    International Nuclear Information System (INIS)

    Jaunet, P.

    2010-01-01

    After Chernobyl accident in 1986, the government began to implement mechanisms to ensure the quality of measurements of environmental radioactivity and to assure the transparency of information on environmental radioactivity monitoring results. Within this context, the French National Network for the Measurement of Environmental Radioactivity (RNM), is created in 2002 under the Public Health Code. This network is developed under the auspices of ASN in collaboration with IRSN and in partnership with government departments, major nuclear licensees, health agencies and environmental protection associations. In order to centralize information on environmental radioactivity and to provide access to measurement results, a single database that includes an the results of measurements of radioactivity in the environment on the national territory is build and a new web-site www.mesure-radioactivite.fr is launched. It provides quick and easy access to this database. The quality of measurements is performed by a laboratory system through an ASN decision. Novel initiative in Europe, the French National Network for the Measurement of Environmental Radioactivity web-site gives the user keys to understand the measurement results on the radiological state of the environment. The site will be improved over the time taking into account the feedback of the users. (author)

  9. A Typology of Social Capital and Associated Network Measures

    OpenAIRE

    Jackson, Matthew O.

    2017-01-01

    I provide a typology of social capital, breaking it down into seven more fundamental forms of capital: information capital, brokerage capital, coordination and leadership capital, bridging capital, favor capital, reputation capital, and community capital. I discuss how most of these forms of social capital can be identified using different network-based measures.

  10. Measuring Personal Networks and Their Relationship with Scientific Production

    Science.gov (United States)

    Villanueva-Felez, Africa; Molas-Gallart, Jordi; Escribá-Esteve, Alejandro

    2013-01-01

    The analysis of social networks has remained a crucial and yet understudied aspect of the efforts to measure Triple Helix linkages. The Triple Helix model aims to explain, among other aspects of knowledge-based societies, "the current research system in its social context" (Etzkowitz and Leydesdorff 2000:109). This paper develops a novel…

  11. Real-Time Alpine Measurement System Using Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Sami A. Malek

    2017-11-01

    Full Text Available Monitoring the snow pack is crucial for many stakeholders, whether for hydro-power optimization, water management or flood control. Traditional forecasting relies on regression methods, which often results in snow melt runoff predictions of low accuracy in non-average years. Existing ground-based real-time measurement systems do not cover enough physiographic variability and are mostly installed at low elevations. We present the hardware and software design of a state-of-the-art distributed Wireless Sensor Network (WSN-based autonomous measurement system with real-time remote data transmission that gathers data of snow depth, air temperature, air relative humidity, soil moisture, soil temperature, and solar radiation in physiographically representative locations. Elevation, aspect, slope and vegetation are used to select network locations, and distribute sensors throughout a given network location, since they govern snow pack variability at various scales. Three WSNs were installed in the Sierra Nevada of Northern California throughout the North Fork of the Feather River, upstream of the Oroville dam and multiple powerhouses along the river. The WSNs gathered hydrologic variables and network health statistics throughout the 2017 water year, one of northern Sierra’s wettest years on record. These networks leverage an ultra-low-power wireless technology to interconnect their components and offer recovery features, resilience to data loss due to weather and wildlife disturbances and real-time topological visualizations of the network health. Data show considerable spatial variability of snow depth, even within a 1 km 2 network location. Combined with existing systems, these WSNs can better detect precipitation timing and phase in, monitor sub-daily dynamics of infiltration and surface runoff during precipitation or snow melt, and inform hydro power managers about actual ablation and end-of-season date across the landscape.

  12. Real-Time Alpine Measurement System Using Wireless Sensor Networks.

    Science.gov (United States)

    Malek, Sami A; Avanzi, Francesco; Brun-Laguna, Keoma; Maurer, Tessa; Oroza, Carlos A; Hartsough, Peter C; Watteyne, Thomas; Glaser, Steven D

    2017-11-09

    Monitoring the snow pack is crucial for many stakeholders, whether for hydro-power optimization, water management or flood control. Traditional forecasting relies on regression methods, which often results in snow melt runoff predictions of low accuracy in non-average years. Existing ground-based real-time measurement systems do not cover enough physiographic variability and are mostly installed at low elevations. We present the hardware and software design of a state-of-the-art distributed Wireless Sensor Network (WSN)-based autonomous measurement system with real-time remote data transmission that gathers data of snow depth, air temperature, air relative humidity, soil moisture, soil temperature, and solar radiation in physiographically representative locations. Elevation, aspect, slope and vegetation are used to select network locations, and distribute sensors throughout a given network location, since they govern snow pack variability at various scales. Three WSNs were installed in the Sierra Nevada of Northern California throughout the North Fork of the Feather River, upstream of the Oroville dam and multiple powerhouses along the river. The WSNs gathered hydrologic variables and network health statistics throughout the 2017 water year, one of northern Sierra's wettest years on record. These networks leverage an ultra-low-power wireless technology to interconnect their components and offer recovery features, resilience to data loss due to weather and wildlife disturbances and real-time topological visualizations of the network health. Data show considerable spatial variability of snow depth, even within a 1 km 2 network location. Combined with existing systems, these WSNs can better detect precipitation timing and phase in, monitor sub-daily dynamics of infiltration and surface runoff during precipitation or snow melt, and inform hydro power managers about actual ablation and end-of-season date across the landscape.

  13. Internal Interface Diversification as a Security Measure in Sensor Networks

    Directory of Open Access Journals (Sweden)

    Sampsa Rauti

    2018-03-01

    Full Text Available More actuator and sensor devices are connected to the Internet of Things (IoT every day, and the network keeps growing, while software security of the devices is often incomplete. Sensor networks and the IoT in general currently cover a large number of devices with an identical internal interface structure. By diversifying the internal interfaces, the interfaces on each node of the network are made unique, and it is possible to break the software monoculture of easily exploitable identical systems. This paper proposes internal interface diversification as a security measure for sensor networks. We conduct a study on diversifiable internal interfaces in 20 IoT operating systems. We also present two proof-of-concept implementations and perform experiments to gauge the feasibility in the IoT environment. Internal interface diversification has practical limitations, and not all IoT operating systems have that many diversifiable interfaces. However, because of low resource requirements, compatibility with other security measures and wide applicability to several interfaces, we believe internal interface diversification is a promising and effective approach for securing nodes in sensor networks.

  14. A measure theoretic approach to traffic flow optimization on networks

    OpenAIRE

    Cacace, Simone; Camilli, Fabio; De Maio, Raul; Tosin, Andrea

    2018-01-01

    We consider a class of optimal control problems for measure-valued nonlinear transport equations describing traffic flow problems on networks. The objective isto minimise/maximise macroscopic quantities, such as traffic volume or average speed,controlling few agents, for example smart traffic lights and automated cars. The measuretheoretic approach allows to study in a same setting local and nonlocal drivers interactionsand to consider the control variables as additional measures interacting ...

  15. The design of nuclear radiation measuring instrument of embedded network

    International Nuclear Information System (INIS)

    Zhang Huaiqiang; Ge Liangquan; Xiong Shengqing

    2009-01-01

    The design and realization of nuclear radiation measuring instrument is introduced. Due to the current nuclear instrument often used serial interface to communicate the PC, it is widely used for simple design and easy operation. However, as the demand of remote data acquisition and the call of sharing resources, the design of embedded the TCP/IP protocol stack into MCU, it may send the nuclear signal in Internet. Some devices that link each other with the network can be networked. The design is not only realizing remote data acquisition and sharing resources, but also reducing costs and improving the maintainability of the system. (authors)

  16. Measuring and evaluating energy consumption in street lighting networks

    International Nuclear Information System (INIS)

    Janiga, P.; Gasparovsky, D.

    2012-01-01

    Smart metering and smart grid are incoming technologies that provide new opportunities in various fields. In connection with the issue of evaluation of the energy aspects of public lighting networks opens up the possibility of evaluating and measuring consumption. Based on the obtained values would be possible to determine energy consumption of lighting systems. This obtained value could serve as a basis for comparing the relevant networks and thus the optimality assessment of lighting designs. Currently, the measure placed in the switchboard of public lighting. If we have considered sections parametramim same lighting, it is necessary to obtain more value from the measured or determined to assess the consumption of time. Proposal of such methods is still under construction but the basic methods have already been outlined. (Authors)

  17. Measuring co-authorship and networking-adjusted scientific impact.

    Directory of Open Access Journals (Sweden)

    John P A Ioannidis

    Full Text Available Appraisal of the scientific impact of researchers, teams and institutions with productivity and citation metrics has major repercussions. Funding and promotion of individuals and survival of teams and institutions depend on publications and citations. In this competitive environment, the number of authors per paper is increasing and apparently some co-authors don't satisfy authorship criteria. Listing of individual contributions is still sporadic and also open to manipulation. Metrics are needed to measure the networking intensity for a single scientist or group of scientists accounting for patterns of co-authorship. Here, I define I(1 for a single scientist as the number of authors who appear in at least I(1 papers of the specific scientist. For a group of scientists or institution, I(n is defined as the number of authors who appear in at least I(n papers that bear the affiliation of the group or institution. I(1 depends on the number of papers authored N(p. The power exponent R of the relationship between I(1 and N(p categorizes scientists as solitary (R>2.5, nuclear (R = 2.25-2.5, networked (R = 2-2.25, extensively networked (R = 1.75-2 or collaborators (R<1.75. R may be used to adjust for co-authorship networking the citation impact of a scientist. I(n similarly provides a simple measure of the effective networking size to adjust the citation impact of groups or institutions. Empirical data are provided for single scientists and institutions for the proposed metrics. Cautious adoption of adjustments for co-authorship and networking in scientific appraisals may offer incentives for more accountable co-authorship behaviour in published articles.

  18. [Vocational orientation in medical rehabilitation: development of a practice handbook and a homepage as user-oriented media for rehabilitative practice].

    Science.gov (United States)

    Lukasczik, M; Löffler, S; Gerlich, C; Wolf, H-D; Neuderth, S

    2011-06-01

    Vocational orientation in medical rehabilitation has become an important issue in rehabilitation science and practice in Germany. Although a variety of vocationally oriented interventions has been developed in recent years, there is still a lack of consensus with regard to the definition of specific types of interventions as well as relevant criteria (e. g., methods; instruments; duration/frequency; patient groups). Building on preliminary definitions, basic types of vocationally oriented measures/interventions were conceptually modified and refined in the context of a consensual process. 39 experts of various professions were contacted during a 2-stage Delphi survey to evaluate existing definitions of vocationally oriented interventions using key questions. Standardized descriptions of 5 vocationally oriented basic interventions were specified in cooperation with an interdisciplinary panel of experts. Descriptions were published in a workbook and a homepage for researchers and clinicians, which also contain information on the implementation of measures into rehabilitative care as well as good practice examples. The media developed in this project may contribute to the transfer of research results on vocationally oriented rehabilitation into health care practice. © Georg Thieme Verlag KG Stuttgart · New York.

  19. Measuring Social Capital in Virtual Social Networks; Introducing Workable Indices

    Directory of Open Access Journals (Sweden)

    Hamid Abdollahian

    2013-12-01

    Full Text Available This paper will attempt to offer a set of indicators that together construct a model which will help to measure social capital among users of social networks. The world is now experiencing some new changes that are affecting conceptual equations in social sciences, two of which are of our concern here: 1- the concept of social capital that has opened its way into epistemological basis of social sciences, and; 2- the world has welcomed the birth and development of social networks in our daily life, affecting many aspects of social actions. There is Facebook from among a handful of social networks that has reached the threshold of international networking capacity with roughly one billion users. We will use Robert Putnam's theory of social capital alongside Frank's methodological innovation regarding measuring tools of social capital in order to create a marriage between these two as well as to address a yet more problematizing issue, i.e., how to measure social capital of the Facebook users. Accordingly the paper will focus on Facebook as the field of research and will introduce triangulation approach that we used in order to come up with the set of indicators. Participatory observation and online survey were used as constructing elements of triangulation approach so to generate the necessary data for the above purpose. At first, we used participatory observation through which 14 targeted samples were selected and whatever they had in their profile in Facebook were collected and analyzed. This analysis helped us to construct our questionnaire which was launched through Google docs. In the end, some 218 respondent returned their completed questionnaires. The final stage of analysis consisted of finding out how we can use the results to offer a new tool for measuring social capital of Facebook users. The research findings indicated that there are 10 indicators which should be put together if social capital is to be properly measured.

  20. Measuring large-scale social networks with high resolution.

    Directory of Open Access Journals (Sweden)

    Arkadiusz Stopczynski

    Full Text Available This paper describes the deployment of a large-scale study designed to measure human interactions across a variety of communication channels, with high temporal resolution and spanning multiple years-the Copenhagen Networks Study. Specifically, we collect data on face-to-face interactions, telecommunication, social networks, location, and background information (personality, demographics, health, politics for a densely connected population of 1000 individuals, using state-of-the-art smartphones as social sensors. Here we provide an overview of the related work and describe the motivation and research agenda driving the study. Additionally, the paper details the data-types measured, and the technical infrastructure in terms of both backend and phone software, as well as an outline of the deployment procedures. We document the participant privacy procedures and their underlying principles. The paper is concluded with early results from data analysis, illustrating the importance of multi-channel high-resolution approach to data collection.

  1. Benchmarking Measures of Network Controllability on Canonical Graph Models

    Science.gov (United States)

    Wu-Yan, Elena; Betzel, Richard F.; Tang, Evelyn; Gu, Shi; Pasqualetti, Fabio; Bassett, Danielle S.

    2018-03-01

    The control of networked dynamical systems opens the possibility for new discoveries and therapies in systems biology and neuroscience. Recent theoretical advances provide candidate mechanisms by which a system can be driven from one pre-specified state to another, and computational approaches provide tools to test those mechanisms in real-world systems. Despite already having been applied to study network systems in biology and neuroscience, the practical performance of these tools and associated measures on simple networks with pre-specified structure has yet to be assessed. Here, we study the behavior of four control metrics (global, average, modal, and boundary controllability) on eight canonical graphs (including Erdős-Rényi, regular, small-world, random geometric, Barábasi-Albert preferential attachment, and several modular networks) with different edge weighting schemes (Gaussian, power-law, and two nonparametric distributions from brain networks, as examples of real-world systems). We observe that differences in global controllability across graph models are more salient when edge weight distributions are heavy-tailed as opposed to normal. In contrast, differences in average, modal, and boundary controllability across graph models (as well as across nodes in the graph) are more salient when edge weight distributions are less heavy-tailed. Across graph models and edge weighting schemes, average and modal controllability are negatively correlated with one another across nodes; yet, across graph instances, the relation between average and modal controllability can be positive, negative, or nonsignificant. Collectively, these findings demonstrate that controllability statistics (and their relations) differ across graphs with different topologies and that these differences can be muted or accentuated by differences in the edge weight distributions. More generally, our numerical studies motivate future analytical efforts to better understand the mathematical

  2. Skill networks and measures of complex human capital.

    Science.gov (United States)

    Anderson, Katharine A

    2017-11-28

    We propose a network-based method for measuring worker skills. We illustrate the method using data from an online freelance website. Using the tools of network analysis, we divide skills into endogenous categories based on their relationship with other skills in the market. Workers who specialize in these different areas earn dramatically different wages. We then show that, in this market, network-based measures of human capital provide additional insight into wages beyond traditional measures. In particular, we show that workers with diverse skills earn higher wages than those with more specialized skills. Moreover, we can distinguish between two different types of workers benefiting from skill diversity: jacks-of-all-trades, whose skills can be applied independently on a wide range of jobs, and synergistic workers, whose skills are useful in combination and fill a hole in the labor market. On average, workers whose skills are synergistic earn more than jacks-of-all-trades. Copyright © 2017 the Author(s). Published by PNAS.

  3. Measuring the degree of integration for an integrated service network

    Directory of Open Access Journals (Sweden)

    Chenglin Ye

    2012-09-01

    Full Text Available Background: Integration involves the coordination of services provided by autonomous agencies and improves the organization and delivery of multiple services for target patients. Current measures generally do not distinguish between agencies' perception and expectation. We propose a method for quantifying the agencies' service integration. Using the data from the Children's Treatment Network (CTN, we aimed to measure the degree of integration for the CTN agencies in York and Simcoe.  Theory and Methods: We quantified the integration by the agreement between perceived and expected levels of involvement and calculated four scores from different perspectives for each agency. We used the average score to measure the global network integration and examined the sensitivity of the global score.  Results: Most agencies' integration scores were less than 65%. As measured by the agreement between every other agency's perception and expectation, the overall integration of CTN in Simcoe and York was 44% (95% CI: 39% - 49% and 52% (95% CI: 48% - 56%, respectively. The sensitivity analysis showed that the global scores were robust.  Conclusion: Our method extends existing measures of integration and possesses a good extent of validity. We can also apply the method in monitoring improvement and linking integration with other outcomes.

  4. Measuring the degree of integration for an integrated service network

    Directory of Open Access Journals (Sweden)

    Chenglin Ye

    2012-09-01

    Full Text Available Background: Integration involves the coordination of services provided by autonomous agencies and improves the organization and delivery of multiple services for target patients. Current measures generally do not distinguish between agencies' perception and expectation. We propose a method for quantifying the agencies' service integration. Using the data from the Children's Treatment Network (CTN, we aimed to measure the degree of integration for the CTN agencies in York and Simcoe. Theory and Methods: We quantified the integration by the agreement between perceived and expected levels of involvement and calculated four scores from different perspectives for each agency. We used the average score to measure the global network integration and examined the sensitivity of the global score. Results: Most agencies' integration scores were less than 65%. As measured by the agreement between every other agency's perception and expectation, the overall integration of CTN in Simcoe and York was 44% (95% CI: 39% - 49% and 52% (95% CI: 48% - 56%, respectively. The sensitivity analysis showed that the global scores were robust. Conclusion: Our method extends existing measures of integration and possesses a good extent of validity. We can also apply the method in monitoring improvement and linking integration with other outcomes. 

  5. Measurement of agricultural parameters using wireless sensor network (WSN)

    Science.gov (United States)

    Guaña-Moya, Javier; Sánchez-Almeida, Tarquino; Salgado-Reyes, Nelson

    2018-04-01

    The technological advances have allowed to create new applications in telecommunications, applying low power and reduced costs in their equipment, thus achieving the evolution of new wireless networks or also denominated Wireless Sensor Network. These technologies allow the generation of measurements and analysis of environmental parameter data and soil. Precision agriculture requires parameters for the improvement of production, obtained through WSN technologies. This research analyzes the climatic requirements and soil parameters in a rose plantation in a greenhouse at an altitude of 3,100 meters above sea level. In the present investigation, maximum parameters were obtained in the production of roses, which are in the optimum range of production, whereas the minimum parameters of temperature, humidity and luminosity, evidenced that these parameters can damage the plants, since temperatures less than 10 °C slow down the growth of the plant and allow the proliferation of diseases and fungi.

  6. Reactor building indoor wireless network channel quality estimation using RSSI measurement of wireless sensor network

    International Nuclear Information System (INIS)

    Merat, S.

    2008-01-01

    Expanding wireless communication network reception inside reactor buildings (RB) and service wings (SW) has always been a technical challenge for operations service team. This is driven by the volume of metal equipment inside the Reactor Buildings (RB) that blocks and somehow shields the signal throughout the link. In this study, to improve wireless reception inside the Reactor Building (RB), an experimental model using indoor localization mesh based on IEEE 802.15 is developed to implement a wireless sensor network. This experimental model estimates the distance between different nodes by measuring the RSSI (Received Signal Strength Indicator). Then by using triangulation and RSSI measurement, the validity of the estimation techniques is verified to simulate the physical environmental obstacles, which block the signal transmission. (author)

  7. Reactor building indoor wireless network channel quality estimation using RSSI measurement of wireless sensor network

    Energy Technology Data Exchange (ETDEWEB)

    Merat, S. [Wardrop Engineering Inc., Toronto, Ontario (Canada)

    2008-07-01

    Expanding wireless communication network reception inside reactor buildings (RB) and service wings (SW) has always been a technical challenge for operations service team. This is driven by the volume of metal equipment inside the Reactor Buildings (RB) that blocks and somehow shields the signal throughout the link. In this study, to improve wireless reception inside the Reactor Building (RB), an experimental model using indoor localization mesh based on IEEE 802.15 is developed to implement a wireless sensor network. This experimental model estimates the distance between different nodes by measuring the RSSI (Received Signal Strength Indicator). Then by using triangulation and RSSI measurement, the validity of the estimation techniques is verified to simulate the physical environmental obstacles, which block the signal transmission. (author)

  8. pO2 measurements in arteriolar networks.

    Science.gov (United States)

    Torres Filho, I P; Kerger, H; Intaglietta, M

    1996-03-01

    Previous studies from our laboratory have shown that the average arteriolar pO2 in the hamster skinfold preparation is lower than arterial systemic pO2. In the present work we tested the hypothesis that there is a longitudinal gradient of pO2 along precapillary vessels. Experiments were performed in Syrian golden hamsters bearing a dorsal skin chamber. The oxygen-dependent quenching of phosphorescence of palladium-porphyrin complexes was used to measure intravascular pO2 in the microcirculation. Arterioles were classified in four orders according to their position in the network, first-order vessels being the entrance points. Simultaneous determinations of diameter (D), red blood cell velocity, and systemic blood gases were also made. There was a significant fall of pO2 between vessels of different orders. First-order arterioles (mean D = 64 microns) had pO2 of 51.8 +/- 9.8 mm Hg (mean +/- SD) which was equivalent to approximately equal to 73% of the arterial systemic pO2. Within the arteriolar network, further decreases of intravascular pO2 were measured, leading to a pO2 of 34.0 +/- 7.9 mm Hg in terminal arterioles (mean D = 7.7 microns). In some vessels pO2 was measured in different positions of the same arteriole. The average longitudinal arteriolar oxygen saturation gradient was 3.4 +/- 0.4 delta %/mm (range 0.8-7.2). A significant and positive correlation was found between pO2 and microhemodynamic parameters when arterioles were grouped according to their order. This relation was not significant for venules which showed a mean pO2 of 30.8 +/- 10.8 mm Hg. Tissue pO2 averaged 24.6 +/- 5.8 mm Hg. We conclude that: (1) There is an oxygen loss in arterial vessels larger than 100 micrograms in diameter, (2) arteriolar pO2 in this preparation depends on the position of the vessel within the network, (3) a substantial portion of oxygen delivery to the hamster skin is provided by the arteriolar network, and (4) only a small pO2 gradient exists between terminal

  9. Inferring a Drive-Response Network from Time Series of Topological Measures in Complex Networks with Transfer Entropy

    Directory of Open Access Journals (Sweden)

    Xinbo Ai

    2014-11-01

    Full Text Available Topological measures are crucial to describe, classify and understand complex networks. Lots of measures are proposed to characterize specific features of specific networks, but the relationships among these measures remain unclear. Taking into account that pulling networks from different domains together for statistical analysis might provide incorrect conclusions, we conduct our investigation with data observed from the same network in the form of simultaneously measured time series. We synthesize a transfer entropy-based framework to quantify the relationships among topological measures, and then to provide a holistic scenario of these measures by inferring a drive-response network. Techniques from Symbolic Transfer Entropy, Effective Transfer Entropy, and Partial Transfer Entropy are synthesized to deal with challenges such as time series being non-stationary, finite sample effects and indirect effects. We resort to kernel density estimation to assess significance of the results based on surrogate data. The framework is applied to study 20 measures across 2779 records in the Technology Exchange Network, and the results are consistent with some existing knowledge. With the drive-response network, we evaluate the influence of each measure by calculating its strength, and cluster them into three classes, i.e., driving measures, responding measures and standalone measures, according to the network communities.

  10. Optimal and secure measurement protocols for quantum sensor networks

    Science.gov (United States)

    Eldredge, Zachary; Foss-Feig, Michael; Gross, Jonathan A.; Rolston, S. L.; Gorshkov, Alexey V.

    2018-04-01

    Studies of quantum metrology have shown that the use of many-body entangled states can lead to an enhancement in sensitivity when compared with unentangled states. In this paper, we quantify the metrological advantage of entanglement in a setting where the measured quantity is a linear function of parameters individually coupled to each qubit. We first generalize the Heisenberg limit to the measurement of nonlocal observables in a quantum network, deriving a bound based on the multiparameter quantum Fisher information. We then propose measurement protocols that can make use of Greenberger-Horne-Zeilinger (GHZ) states or spin-squeezed states and show that in the case of GHZ states the protocol is optimal, i.e., it saturates our bound. We also identify nanoscale magnetic resonance imaging as a promising setting for this technology.

  11. Laser tracker error determination using a network measurement

    International Nuclear Information System (INIS)

    Hughes, Ben; Forbes, Alistair; Lewis, Andrew; Sun, Wenjuan; Veal, Dan; Nasr, Karim

    2011-01-01

    We report on a fast, easily implemented method to determine all the geometrical alignment errors of a laser tracker, to high precision. The technique requires no specialist equipment and can be performed in less than an hour. The technique is based on the determination of parameters of a geometric model of the laser tracker, using measurements of a set of fixed target locations, from multiple locations of the tracker. After fitting of the model parameters to the observed data, the model can be used to perform error correction of the raw laser tracker data or to derive correction parameters in the format of the tracker manufacturer's internal error map. In addition to determination of the model parameters, the method also determines the uncertainties and correlations associated with the parameters. We have tested the technique on a commercial laser tracker in the following way. We disabled the tracker's internal error compensation, and used a five-position, fifteen-target network to estimate all the geometric errors of the instrument. Using the error map generated from this network test, the tracker was able to pass a full performance validation test, conducted according to a recognized specification standard (ASME B89.4.19-2006). We conclude that the error correction determined from the network test is as effective as the manufacturer's own error correction methodologies

  12. Automated Measurement and Signaling Systems for the Transactional Network

    Energy Technology Data Exchange (ETDEWEB)

    Piette, Mary Ann; Brown, Richard; Price, Phillip; Page, Janie; Granderson, Jessica; Riess, David; Czarnecki, Stephen; Ghatikar, Girish; Lanzisera, Steven

    2013-12-31

    The Transactional Network Project is a multi-lab activity funded by the US Department of Energy?s Building Technologies Office. The project team included staff from Lawrence Berkeley National Laboratory, Pacific Northwest National Laboratory and Oak Ridge National Laboratory. The team designed, prototyped and tested a transactional network (TN) platform to support energy, operational and financial transactions between any networked entities (equipment, organizations, buildings, grid, etc.). PNNL was responsible for the development of the TN platform, with agents for this platform developed by each of the three labs. LBNL contributed applications to measure the whole-building electric load response to various changes in building operations, particularly energy efficiency improvements and demand response events. We also provide a demand response signaling agent and an agent for cost savings analysis. LBNL and PNNL demonstrated actual transactions between packaged rooftop units and the electric grid using the platform and selected agents. This document describes the agents and applications developed by the LBNL team, and associated tests of the applications.

  13. Measuring co-authorship and networking-adjusted scientific impact.

    Science.gov (United States)

    Ioannidis, John P A

    2008-07-23

    Appraisal of the scientific impact of researchers, teams and institutions with productivity and citation metrics has major repercussions. Funding and promotion of individuals and survival of teams and institutions depend on publications and citations. In this competitive environment, the number of authors per paper is increasing and apparently some co-authors don't satisfy authorship criteria. Listing of individual contributions is still sporadic and also open to manipulation. Metrics are needed to measure the networking intensity for a single scientist or group of scientists accounting for patterns of co-authorship. Here, I define I(1) for a single scientist as the number of authors who appear in at least I(1) papers of the specific scientist. For a group of scientists or institution, I(n) is defined as the number of authors who appear in at least I(n) papers that bear the affiliation of the group or institution. I(1) depends on the number of papers authored N(p). The power exponent R of the relationship between I(1) and N(p) categorizes scientists as solitary (R>2.5), nuclear (R = 2.25-2.5), networked (R = 2-2.25), extensively networked (R = 1.75-2) or collaborators (Raccountable co-authorship behaviour in published articles.

  14. Hierarchical anatomical brain networks for MCI prediction: revisiting volumetric measures.

    Directory of Open Access Journals (Sweden)

    Luping Zhou

    Full Text Available Owning to its clinical accessibility, T1-weighted MRI (Magnetic Resonance Imaging has been extensively studied in the past decades for prediction of Alzheimer's disease (AD and mild cognitive impairment (MCI. The volumes of gray matter (GM, white matter (WM and cerebrospinal fluid (CSF are the most commonly used measurements, resulting in many successful applications. It has been widely observed that disease-induced structural changes may not occur at isolated spots, but in several inter-related regions. Therefore, for better characterization of brain pathology, we propose in this paper a means to extract inter-regional correlation based features from local volumetric measurements. Specifically, our approach involves constructing an anatomical brain network for each subject, with each node representing a Region of Interest (ROI and each edge representing Pearson correlation of tissue volumetric measurements between ROI pairs. As second order volumetric measurements, network features are more descriptive but also more sensitive to noise. To overcome this limitation, a hierarchy of ROIs is used to suppress noise at different scales. Pairwise interactions are considered not only for ROIs with the same scale in the same layer of the hierarchy, but also for ROIs across different scales in different layers. To address the high dimensionality problem resulting from the large number of network features, a supervised dimensionality reduction method is further employed to embed a selected subset of features into a low dimensional feature space, while at the same time preserving discriminative information. We demonstrate with experimental results the efficacy of this embedding strategy in comparison with some other commonly used approaches. In addition, although the proposed method can be easily generalized to incorporate other metrics of regional similarities, the benefits of using Pearson correlation in our application are reinforced by the experimental

  15. Calibration-measurement unit for the automation of vector network analyzer measurements

    Directory of Open Access Journals (Sweden)

    I. Rolfes

    2008-05-01

    Full Text Available With the availability of multi-port vector network analyzers, the need for automated, calibrated measurement facilities increases. In this contribution, a calibration-measurement unit is presented which realizes a repeatable automated calibration of the measurement setup as well as a user-friendly measurement of the device under test (DUT. In difference to commercially available calibration units, which are connected to the ports of the vector network analyzer preceding a measurement and which are then removed so that the DUT can be connected, the presented calibration-measurement unit is permanently connected to the ports of the VNA for the calibration as well as for the measurement of the DUT. This helps to simplify the calibrated measurement of complex scattering parameters. Moreover, a full integration of the calibration unit into the analyzer setup becomes possible. The calibration-measurement unit is based on a multiport switch setup of e.g. electromechanical relays. Under the assumption of symmetry of a switch, on the one hand the unit realizes the connection of calibration standards like one-port reflection standards and two-port through connections between different ports and on the other hand it enables the connection of the DUT. The calibration-measurement unit is applicable for two-port VNAs as well as for multiport VNAs. For the calibration of the unit, methods with completely known calibration standards like SOLT (short, open, load, through as well as self-calibration procedures like TMR or TLR can be applied.

  16. Measuring social networks in British primary schools through scientific engagement

    Science.gov (United States)

    Conlan, A. J. K.; Eames, K. T. D.; Gage, J. A.; von Kirchbach, J. C.; Ross, J. V.; Saenz, R. A.; Gog, J. R.

    2011-01-01

    Primary schools constitute a key risk group for the transmission of infectious diseases, concentrating great numbers of immunologically naive individuals at high densities. Despite this, very little is known about the social patterns of mixing within a school, which are likely to contribute to disease transmission. In this study, we present a novel approach where scientific engagement was used as a tool to access school populations and measure social networks between young (4–11 years) children. By embedding our research project within enrichment activities to older secondary school (13–15) children, we could exploit the existing links between schools to achieve a high response rate for our study population (around 90% in most schools). Social contacts of primary school children were measured through self-reporting based on a questionnaire design, and analysed using the techniques of social network analysis. We find evidence of marked social structure and gender assortativity within and between classrooms in the same school. These patterns have been previously reported in smaller studies, but to our knowledge no study has attempted to exhaustively sample entire school populations. Our innovative approach facilitates access to a vitally important (but difficult to sample) epidemiological sub-group. It provides a model whereby scientific communication can be used to enhance, rather than merely complement, the outcomes of research. PMID:21047859

  17. Ekofisk chalk: core measurements, stochastic reconstruction, network modeling and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Talukdar, Saifullah

    2002-07-01

    This dissertation deals with (1) experimental measurements on petrophysical, reservoir engineering and morphological properties of Ekofisk chalk, (2) numerical simulation of core flood experiments to analyze and improve relative permeability data, (3) stochastic reconstruction of chalk samples from limited morphological information, (4) extraction of pore space parameters from the reconstructed samples, development of network model using pore space information, and computation of petrophysical and reservoir engineering properties from network model, and (5) development of 2D and 3D idealized fractured reservoir models and verification of the applicability of several widely used conventional up scaling techniques in fractured reservoir simulation. Experiments have been conducted on eight Ekofisk chalk samples and porosity, absolute permeability, formation factor, and oil-water relative permeability, capillary pressure and resistivity index are measured at laboratory conditions. Mercury porosimetry data and backscatter scanning electron microscope images have also been acquired for the samples. A numerical simulation technique involving history matching of the production profiles is employed to improve the relative permeability curves and to analyze hysteresis of the Ekofisk chalk samples. The technique was found to be a powerful tool to supplement the uncertainties in experimental measurements. Porosity and correlation statistics obtained from backscatter scanning electron microscope images are used to reconstruct microstructures of chalk and particulate media. The reconstruction technique involves a simulated annealing algorithm, which can be constrained by an arbitrary number of morphological parameters. This flexibility of the algorithm is exploited to successfully reconstruct particulate media and chalk samples using more than one correlation functions. A technique based on conditional simulated annealing has been introduced for exact reproduction of vuggy

  18. Measuring symmetry, asymmetry and randomness in neural network connectivity.

    Directory of Open Access Journals (Sweden)

    Umberto Esposito

    Full Text Available Cognitive functions are stored in the connectome, the wiring diagram of the brain, which exhibits non-random features, so-called motifs. In this work, we focus on bidirectional, symmetric motifs, i.e. two neurons that project to each other via connections of equal strength, and unidirectional, non-symmetric motifs, i.e. within a pair of neurons only one neuron projects to the other. We hypothesise that such motifs have been shaped via activity dependent synaptic plasticity processes. As a consequence, learning moves the distribution of the synaptic connections away from randomness. Our aim is to provide a global, macroscopic, single parameter characterisation of the statistical occurrence of bidirectional and unidirectional motifs. To this end we define a symmetry measure that does not require any a priori thresholding of the weights or knowledge of their maximal value. We calculate its mean and variance for random uniform or Gaussian distributions, which allows us to introduce a confidence measure of how significantly symmetric or asymmetric a specific configuration is, i.e. how likely it is that the configuration is the result of chance. We demonstrate the discriminatory power of our symmetry measure by inspecting the eigenvalues of different types of connectivity matrices. We show that a Gaussian weight distribution biases the connectivity motifs to more symmetric configurations than a uniform distribution and that introducing a random synaptic pruning, mimicking developmental regulation in synaptogenesis, biases the connectivity motifs to more asymmetric configurations, regardless of the distribution. We expect that our work will benefit the computational modelling community, by providing a systematic way to characterise symmetry and asymmetry in network structures. Further, our symmetry measure will be of use to electrophysiologists that investigate symmetry of network connectivity.

  19. Measuring symmetry, asymmetry and randomness in neural network connectivity.

    Science.gov (United States)

    Esposito, Umberto; Giugliano, Michele; van Rossum, Mark; Vasilaki, Eleni

    2014-01-01

    Cognitive functions are stored in the connectome, the wiring diagram of the brain, which exhibits non-random features, so-called motifs. In this work, we focus on bidirectional, symmetric motifs, i.e. two neurons that project to each other via connections of equal strength, and unidirectional, non-symmetric motifs, i.e. within a pair of neurons only one neuron projects to the other. We hypothesise that such motifs have been shaped via activity dependent synaptic plasticity processes. As a consequence, learning moves the distribution of the synaptic connections away from randomness. Our aim is to provide a global, macroscopic, single parameter characterisation of the statistical occurrence of bidirectional and unidirectional motifs. To this end we define a symmetry measure that does not require any a priori thresholding of the weights or knowledge of their maximal value. We calculate its mean and variance for random uniform or Gaussian distributions, which allows us to introduce a confidence measure of how significantly symmetric or asymmetric a specific configuration is, i.e. how likely it is that the configuration is the result of chance. We demonstrate the discriminatory power of our symmetry measure by inspecting the eigenvalues of different types of connectivity matrices. We show that a Gaussian weight distribution biases the connectivity motifs to more symmetric configurations than a uniform distribution and that introducing a random synaptic pruning, mimicking developmental regulation in synaptogenesis, biases the connectivity motifs to more asymmetric configurations, regardless of the distribution. We expect that our work will benefit the computational modelling community, by providing a systematic way to characterise symmetry and asymmetry in network structures. Further, our symmetry measure will be of use to electrophysiologists that investigate symmetry of network connectivity.

  20. Preferential Attachment in Online Networks: Measurement and Explanations

    NARCIS (Netherlands)

    Kunegis, J; Blattner, M; Moser, C.

    2013-01-01

    We perform an empirical study of the preferential attachment phenomenon in temporal networks and show that on the Web, networks follow a nonlinear preferential attachment model in which the exponent depends on the type of network considered. The classical preferential attachment model for networks

  1. Energy Consumption Model and Measurement Results for Network Coding-enabled IEEE 802.11 Meshed Wireless Networks

    DEFF Research Database (Denmark)

    Paramanathan, Achuthan; Rasmussen, Ulrik Wilken; Hundebøll, Martin

    2012-01-01

    This paper presents an energy model and energy measurements for network coding enabled wireless meshed networks based on IEEE 802.11 technology. The energy model and the energy measurement testbed is limited to a simple Alice and Bob scenario. For this toy scenario we compare the energy usages...... for a system with and without network coding support. While network coding reduces the number of radio transmissions, the operational activity on the devices due to coding will be increased. We derive an analytical model for the energy consumption and compare it to real measurements for which we build...... a flexible, low cost tool to be able to measure at any given node in a meshed network. We verify the precision of our tool by comparing it to a sophisticated device. Our main results in this paper are the derivation of an analytical energy model, the implementation of a distributed energy measurement testbed...

  2. SKYMONITOR: A Global Network for Sky Brightness Measurements

    Science.gov (United States)

    Davis, Donald R.; Mckenna, D.; Pulvermacher, R.; Everett, M.

    2010-01-01

    We are implementing a global network to measure sky brightness at dark-sky critical sites with the goal of creating a multi-decade database. The heart of this project is the Night Sky Brightness Monitor (NSBM), an autonomous 2 channel photometer which measures night sky brightness in the visual wavelengths (Mckenna et al, AAS 2009). Sky brightness is measured every minute at two elevation angles typically zenith and 20 degrees to monitor brightness and transparency. The NSBM consists of two parts, a remote unit and a base station with an internet connection. Currently these devices use 2.4 Ghz transceivers with a range of 100 meters. The remote unit is battery powered with daytime recharging using a solar panel. Data received by the base unit is transmitted via email protocol to IDA offices in Tucson where it will be collected, archived and made available to the user community via a web interface. Two other versions of the NSBM are under development: one for radio sensitive areas using an optical fiber link and the second that reads data directly to a laptop for sites without internet access. NSBM units are currently undergoing field testing at two observatories. With support from the National Science Foundation, we will construct and install a total of 10 units at astronomical observatories. With additional funding, we will locate additional units at other sites such as National Parks, dark-sky preserves and other sites where dark sky preservation is crucial. We will present the current comparison with the National Park Service sky monitoring camera. We anticipate that the SKYMONITOR network will be functioning by the end of 2010.

  3. Node-based measures of connectivity in genetic networks.

    Science.gov (United States)

    Koen, Erin L; Bowman, Jeff; Wilson, Paul J

    2016-01-01

    At-site environmental conditions can have strong influences on genetic connectivity, and in particular on the immigration and settlement phases of dispersal. However, at-site processes are rarely explored in landscape genetic analyses. Networks can facilitate the study of at-site processes, where network nodes are used to model site-level effects. We used simulated genetic networks to compare and contrast the performance of 7 node-based (as opposed to edge-based) genetic connectivity metrics. We simulated increasing node connectivity by varying migration in two ways: we increased the number of migrants moving between a focal node and a set number of recipient nodes, and we increased the number of recipient nodes receiving a set number of migrants. We found that two metrics in particular, the average edge weight and the average inverse edge weight, varied linearly with simulated connectivity. Conversely, node degree was not a good measure of connectivity. We demonstrated the use of average inverse edge weight to describe the influence of at-site habitat characteristics on genetic connectivity of 653 American martens (Martes americana) in Ontario, Canada. We found that highly connected nodes had high habitat quality for marten (deep snow and high proportions of coniferous and mature forest) and were farther from the range edge. We recommend the use of node-based genetic connectivity metrics, in particular, average edge weight or average inverse edge weight, to model the influences of at-site habitat conditions on the immigration and settlement phases of dispersal. © 2015 John Wiley & Sons Ltd.

  4. Development of Light Powered Sensor Networks for Thermal Comfort Measurement

    Directory of Open Access Journals (Sweden)

    Dasheng Lee

    2008-10-01

    Full Text Available Recent technological advances in wireless communications have enabled easy installation of sensor networks with air conditioning equipment control applications. However, the sensor node power supply, through either power lines or battery power, still presents obstacles to the distribution of the sensing systems. In this study, a novel sensor network, powered by the artificial light, was constructed to achieve wireless power transfer and wireless data communications for thermal comfort measurements. The sensing node integrates an IC-based temperature sensor, a radiation thermometer, a relative humidity sensor, a micro machined flow sensor and a microprocessor for predicting mean vote (PMV calculation. The 935 MHz band RF module was employed for the wireless data communication with a specific protocol based on a special energy beacon enabled mode capable of achieving zero power consumption during the inactive periods of the nodes. A 5W spotlight, with a dual axis tilt platform, can power the distributed nodes over a distance of up to 5 meters. A special algorithm, the maximum entropy method, was developed to estimate the sensing quantity of climate parameters if the communication module did not receive any response from the distributed nodes within a certain time limit. The light-powered sensor networks were able to gather indoor comfort-sensing index levels in good agreement with the comfort-sensing vote (CSV preferred by a human being and the experimental results within the environment suggested that the sensing system could be used in air conditioning systems to implement a comfort-optimal control strategy.

  5. Black Carbon Measurements From Ireland's Transboundary Network (TXB)

    Science.gov (United States)

    Spohn, T. K.; Martin, D.; O'Dowd, C. D. D.

    2017-12-01

    Black Carbon (BC) is carbonaceous aerosol formed by incomplete fossil fuel combustion. Named for its light absorbing properties, it acts to trap heat in the atmosphere, thus behaving like a greenhouse gas, and is considered a strong, short-lived climate forcer by the International Panel on Climate Change (IPCC). Carbonaceous aerosols from biomass burning (BB) such as forest fires and residential wood burning, also known as brown carbon, affect the ultra violet (UV) light absorption in the atmosphere as well. In 2016 a three node black carbon monitoring network was established in Ireland as part of a Transboundary Monitoring Network (TXB). The three sites (Mace Head, Malin Head, and Carnsore Point) are coastal locations on opposing sides of the country, and offer the opportunity to assess typical northern hemispheric background concentrations as well national and European pollution events. The instruments deployed in this network (Magee Scientific AE33) facilitate elimination of the changes in response due to `aerosol loading' effects; and a real-time calculation of the `loading compensation' parameter which offers insights into aerosol optical properties. Additionally, these instruments have an inbuilt algorithm, which estimates the difference in absorption in the ultraviolet wavelengths (mostly by brown carbon) and the near infrared wavelengths (only by black carbon).Presented here are the first results of the BC measurements from the three Irish stations, including instrument validation, seasonal variation as well as local, regional, and transboundary influences based on air mass trajectories as well as concurrent in-situ observations (meteorological parameters, particle number, and aerosol composition). A comparison of the instrumental algorithm to off-line sensitivity calculations will also be made to assess the contribution of biomass burning to BC pollution events.

  6. Continuous measurements of methane from a tower network over Siberia

    International Nuclear Information System (INIS)

    Sasakawa, M.; Machida, T.; Saeki, T.; Koyama, Y.; Maksyutov, S.; Shimoyama, K.; Tsuda, N.; Suto, H.; Arshinov, M.; Davydov, D.; Fofonov, A.; Krasnov, O.

    2010-01-01

    We have been conducting continuous measurements of Methane (CH 4 ) concentration from an expanding network of towers (JR-STATION: Japan-Russia Siberian Tall Tower Inland Observation Network) located in taiga, steppe and wetland biomes of Siberia since 2004. High daytime means (>2000 ppb) observed simultaneously at several towers during winter, together with in situ weather data and NCEP/NCAR reanalysis data, indicate that high pressure systems caused CH 4 accumulation at subcontinental scale due to the widespread formation of an inversion layer. Daytime means sometimes exceeded 2000 ppb, particularly in the summer of 2007 when temperature and precipitation rates were anomalously high over West Siberia, which implies that CH 4 emission from wetlands were exceptionally high in 2007. Many hot spots detected by MODIS in the summer of 2007 illustrate that the contribution of biomass burning also cannot be neglected. Daytime mean CH 4 concentrations from the Siberian tower sites were generally higher than CH 4 values reported at NOAA coastal sites in the same latitudinal zone, and the difference in concentrations between two sets of sites was reproduced with a coupled Eulerian-Lagrangian transport model. Simulations of emissions from different CH 4 sources suggested that the major contributor to variation switched from wetlands during summer to fossil fuel during winter.

  7. Continuous measurements of methane from a tower network over Siberia

    Energy Technology Data Exchange (ETDEWEB)

    Sasakawa, M.; Machida, T.; Saeki, T.; Koyama, Y.; Maksyutov, S. (Center for Global Environmental Research, National Inst. for Environmental Studies, Tsukuba, Ibaraki (Japan)); Shimoyama, K. (Inst. of Low Temperature Science, Hokkaido Univ., Hokkaido (Japan)); Tsuda, N. (Global Environmental Forum, Tokyo (Japan)); Suto, H. (Japan Aerospace Exploration Agency (Japan)); Arshinov, M.; Davydov, D.; Fofonov, A.; Krasnov, O. (Inst. of Atmospheric Optics, Russian Academy of Sciences, Siberian Branch (Russian Federation))

    2010-11-15

    We have been conducting continuous measurements of Methane (CH{sub 4}) concentration from an expanding network of towers (JR-STATION: Japan-Russia Siberian Tall Tower Inland Observation Network) located in taiga, steppe and wetland biomes of Siberia since 2004. High daytime means (>2000 ppb) observed simultaneously at several towers during winter, together with in situ weather data and NCEP/NCAR reanalysis data, indicate that high pressure systems caused CH{sub 4} accumulation at subcontinental scale due to the widespread formation of an inversion layer. Daytime means sometimes exceeded 2000 ppb, particularly in the summer of 2007 when temperature and precipitation rates were anomalously high over West Siberia, which implies that CH{sub 4} emission from wetlands were exceptionally high in 2007. Many hot spots detected by MODIS in the summer of 2007 illustrate that the contribution of biomass burning also cannot be neglected. Daytime mean CH{sub 4} concentrations from the Siberian tower sites were generally higher than CH{sub 4} values reported at NOAA coastal sites in the same latitudinal zone, and the difference in concentrations between two sets of sites was reproduced with a coupled Eulerian-Lagrangian transport model. Simulations of emissions from different CH{sub 4} sources suggested that the major contributor to variation switched from wetlands during summer to fossil fuel during winter.

  8. Centrality measures in temporal networks with time series analysis

    Science.gov (United States)

    Huang, Qiangjuan; Zhao, Chengli; Zhang, Xue; Wang, Xiaojie; Yi, Dongyun

    2017-05-01

    The study of identifying important nodes in networks has a wide application in different fields. However, the current researches are mostly based on static or aggregated networks. Recently, the increasing attention to networks with time-varying structure promotes the study of node centrality in temporal networks. In this paper, we define a supra-evolution matrix to depict the temporal network structure. With using of the time series analysis, the relationships between different time layers can be learned automatically. Based on the special form of the supra-evolution matrix, the eigenvector centrality calculating problem is turned into the calculation of eigenvectors of several low-dimensional matrices through iteration, which effectively reduces the computational complexity. Experiments are carried out on two real-world temporal networks, Enron email communication network and DBLP co-authorship network, the results of which show that our method is more efficient at discovering the important nodes than the common aggregating method.

  9. Grain bulk density measurement based on wireless network

    Directory of Open Access Journals (Sweden)

    Wu Fangming

    2017-01-01

    Full Text Available To know the accurate quantity of stored grain, grain density sensors must be used to measure the grain’s bulk density. However, multi-sensors should be inserted into the storage facility, to quickly collect data during the inventory checking of stored grain. In this study, the ZigBee and Wi-Fi coexistence network’s ability to transmit data collected by density sensors was investigated. A system consisting of six sensor nodes, six router nodes, one gateway and one Android Pad was assembled to measure the grain’s bulk density and calculate its quantity. The CC2530 chip with ZigBee technology was considered as the core of the information processing, and wireless nodes detection in sensor, and router nodes. ZigBee worked in difference signal channel with Wi-Fi to avoid interferences and connected with Wi-Fi module by UART serial communications interfaces in gateway. The Android Pad received the measured data through the gateway and processed this data to calculate quantity. The system enabled multi-point and real-time parameter detection inside the grain storage. Results show that the system has characteristics of good expansibility, networking flexibility and convenience.

  10. Measurement of company effectiveness using analytic network process method

    Directory of Open Access Journals (Sweden)

    Goran Janjić

    2017-07-01

    Full Text Available The sustainable development of an organisation is monitored through the organisation’s performance, which beforehand incorporates all stakeholders’ requirements in its strategy. The strategic management concept enables organisations to monitor and evaluate their effectiveness along with efficiency by monitoring of the implementation of set strategic goals. In the process of monitoring and measuring effectiveness, an organisation can use multiple-criteria decision-making methods as help. This study uses the method of analytic network process (ANP to define the weight factors of the mutual influences of all the important elements of an organisation’s strategy. The calculation of an organisation’s effectiveness is based on the weight factors and the degree of fulfilment of the goal values of the strategic map measures. New business conditions influence the changes in the importance of certain elements of an organisation’s business in relation to competitive advantage on the market, and on the market, increasing emphasis is given to non-material resources in the process of selection of the organisation’s most important measures.

  11. Measurement of company effectiveness using analytic network process method

    Science.gov (United States)

    Goran, Janjić; Zorana, Tanasić; Borut, Kosec

    2017-07-01

    The sustainable development of an organisation is monitored through the organisation's performance, which beforehand incorporates all stakeholders' requirements in its strategy. The strategic management concept enables organisations to monitor and evaluate their effectiveness along with efficiency by monitoring of the implementation of set strategic goals. In the process of monitoring and measuring effectiveness, an organisation can use multiple-criteria decision-making methods as help. This study uses the method of analytic network process (ANP) to define the weight factors of the mutual influences of all the important elements of an organisation's strategy. The calculation of an organisation's effectiveness is based on the weight factors and the degree of fulfilment of the goal values of the strategic map measures. New business conditions influence the changes in the importance of certain elements of an organisation's business in relation to competitive advantage on the market, and on the market, increasing emphasis is given to non-material resources in the process of selection of the organisation's most important measures.

  12. Multi-attribute integrated measurement of node importance in complex networks.

    Science.gov (United States)

    Wang, Shibo; Zhao, Jinlou

    2015-11-01

    The measure of node importance in complex networks is very important to the research of networks stability and robustness; it also can ensure the security of the whole network. Most researchers have used a single indicator to measure the networks node importance, so that the obtained measurement results only reflect certain aspects of the networks with a loss of information. Meanwhile, because of the difference of networks topology, the nodes' importance should be described by combining the character of the networks topology. Most of the existing evaluation algorithms cannot completely reflect the circumstances of complex networks, so this paper takes into account the degree of centrality, the relative closeness centrality, clustering coefficient, and topology potential and raises an integrated measuring method to measure the nodes' importance. This method can reflect nodes' internal and outside attributes and eliminate the influence of network structure on the node importance. The experiments of karate network and dolphin network show that networks topology structure integrated measure has smaller range of metrical result than a single indicator and more universal. Experiments show that attacking the North American power grid and the Internet network with the method has a faster convergence speed than other methods.

  13. Research on the method of measuring space information network capacity in communication service

    Directory of Open Access Journals (Sweden)

    Zhu Shichao

    2017-02-01

    Full Text Available Because of the large scale characteristic of space information network in terms of space and time and the increasing of its complexity,existing measuring methods of information transmission capacity have been unable to measure the existing and future space information networkeffectively.In this study,we firstly established a complex model of space information network,and measured the whole space information network capacity by means of analyzing data access capability to the network and data transmission capability within the network.At last,we verified the rationality of the proposed measuring method by using STK and Matlab simulation software for collaborative simulation.

  14. Flow-based vulnerability measures for network component importance: Experimentation with preparedness planning

    International Nuclear Information System (INIS)

    Nicholson, Charles D.; Barker, Kash; Ramirez-Marquez, Jose E.

    2016-01-01

    This work develops and compares several flow-based vulnerability measures to prioritize important network edges for the implementation of preparedness options. These network vulnerability measures quantify different characteristics and perspectives on enabling maximum flow, creating bottlenecks, and partitioning into cutsets, among others. The efficacy of these vulnerability measures to motivate preparedness options against experimental geographically located disruption simulations is measured. Results suggest that a weighted flow capacity rate, which accounts for both (i) the contribution of an edge to maximum network flow and (ii) the extent to which the edge is a bottleneck in the network, shows most promise across four instances of varying network sizes and densities. - Highlights: • We develop new flow-based measures of network vulnerability. • We apply these measures to determine the importance of edges after disruptions. • Networks of varying size and density are explored.

  15. New approach in subjective and objective speech transmission quality measurement in TCP/IP networks

    International Nuclear Information System (INIS)

    Souček, Pavel; Slavata, Oldřich; Holub, Jan

    2015-01-01

    This paper deals with problems of speech transmission quality measurement in modern telecommunication networks. It focuses on problems caused by specific types of distortions and errors caused present in transmissions using TCP/IP networks

  16. Measurement of traffic network vulnerability for Mississippi coastal region : final research report.

    Science.gov (United States)

    2017-08-15

    Natural disasters such as a hurricane can cause great damages to the transportation networks and significantly affect the evacuation trip operations. An accurate understanding and measurement of the network vulnerability can enhance the evacuees p...

  17. A Network-Based Impact Measure for Propagated Losses in a Supply Chain Network Consisting of Resilient Components

    Directory of Open Access Journals (Sweden)

    Jesus Felix Bayta Valenzuela

    2018-01-01

    Full Text Available The topology of a supply chain network affects the impacts of disruptions in it. We formulate a network-based measure of the impact of a disruption loss in a supply chain propagating downstream from an originating node. The measure takes into account the loss profile of the originating node, the structure of the supply network, and the resilience of the network components. We obtain an analytical expression for the impact measure under a beta-distributed initial loss (generalizable to any continuous distribution supported on the interval 0,1, under a breakthrough scenario (in which a fraction of the initial production loss reaches a focal company downstream as opposed to containment upstream or at the originating point. Furthermore, we obtain a closed-form solution for a supply chain network with a k-ary tree topology; a numerical study is performed for a scale-free network and a random network. Our proposed approach enables the evaluation of potential losses for a focal company considering its supply chain network structure, which may help the company to plan or redesign a robust and resilient network in response to different types of disruptions.

  18. Stream network responses to evapotranspiration in mountain systems: evidence from spatially-distributed network mapping and sapflow measurements

    Science.gov (United States)

    Godsey, S.; Whiting, J. A.; Reinhardt, K.

    2015-12-01

    Stream networks respond to decreased inputs by shrinking from their headwaters and disconnecting along their length. Both the relative stability of the stream network and the degree of disconnection along the network length can strongly affect stream ecology, including fish migration and nutrient spiraling. Previous data suggests that stream network lengths decrease measurably as discharge decreases, and that evapotranspiration may be an important control on stream network persistence. We hypothesized that changes in sapflow timing and magnitude across a gradient from rain-dominated to snow-dominated elevations would be reflected in the stability of the stream network in a steep watershed draining to the Middle Fork Salmon in central Idaho. We expected that the relative timing of water availability across the gradient would drive differences in water delivery to both trees and the stream network. Here we present results that highlight the stability of sapflow timing across the gradient and persistence of the stream network at this site. We discuss geologic controls on network stability and present a conceptual framework identifying characteristics of stable flowheads. We test this framework at four sites in central Idaho with mapped stream networks. We also discuss late summer sapflow patterns across the elevation gradient and their linkages to soil and atmospheric characteristics. Finally, we compare these patterns to those observed at other sites and discuss the role of vegetation in controlling spatiotemporal patterns across the stream network.

  19. On measurement noise in the European TWSTFT network.

    Science.gov (United States)

    Piester, Dirk; Bauch, Andreas; Becker, Jürgen; Staliuniene, Egle; Schlunegger, Christian

    2008-09-01

    Two-way satellite time and frequency transfer (TWSTFT) using geostationary telecommunication satellites is widely used in the timing community today and has also been chosen as the primary means to effect synchronization of elements of the ground segment of the European satellite navigation system Galileo. We investigated the link performance in a multistation network based on operational parameters such as the number of simultaneously transmitting stations, transmit and receive power, and chip rates of the pseudorandom noise modulation of the transmitted signals. Our work revealed that TWSTFT through a "quiet" transponder channel (2 stations transmitting only) leads to a measurement noise, expressed by the 1 pps jitter, reduced by a factor of 1.4 compared with a busy transponder carrying signals of 12 stations. The frequency transfer capability expressed by the Allan deviation is reduced at short averaging times by the same amount. At averaging times of >1 d, no such reduction could be observed, which points to the fact that other noise sources dominate at such averaging times. We also found that higher transmit power increases the carrier-to-noise density ratio at the receive station and thus entails lower jitter but causes interference with other station's signals. In addition, the use of lower chip rates, which could be accommodated by a reduced assigned bandwidth on the satellite transponder, is not recommended. The 1 pps jitter would go up by a factor of 2.5 when going from 2.5 MCh/s to 1 MCh/s. The 2 Galileo precise timing facilities (PTFs) can be included in the currently operated network of 12 stations in Europe and all requirements on the TWSTFT performance can be met, provided that suitable ground equipment will be installed in the Galileo ground segment.

  20. Assessment of Performance Measures for Security of the Maritime Transportation Network, Port Security Metrics : Proposed Measurement of Deterrence Capability

    Science.gov (United States)

    2007-01-03

    This report is the thirs in a series describing the development of performance measures pertaining to the security of the maritime transportation network (port security metrics). THe development of measures to guide improvements in maritime security ...

  1. The Study on the Communication Network of Wide Area Measurement System in Electricity Grid

    Science.gov (United States)

    Xiaorong, Cheng; Ying, Wang; Yangdan, Ni

    Wide area measurement system(WAMS) is a fundamental part of security defense in Smart Grid, and the communication system of WAMS is an important part of Electric power communication network. For a large regional network is concerned, the real-time data which is transferred in the communication network of WAMS will affect the safe operation of the power grid directly. Therefore, WAMS raised higher requirements for real-time, reliability and security to its communication network. In this paper, the architecture of WASM communication network was studied according to the seven layers model of the open systems interconnection(OSI), and the network architecture was researched from all levels. We explored the media of WAMS communication network, the network communication protocol and network technology. Finally, the delay of the network were analyzed.

  2. Computer Network Availability at Sandia National Laboratories, Albuquerque NM: Measurement and Perception; TOPICAL

    International Nuclear Information System (INIS)

    NELSON, SPENCER D.; TOLENDINO, LAWRENCE F.

    1999-01-01

    The desire to provide a measure of computer network availability at Sandia National Laboratories has existed for along time. Several attempts were made to build this measure by accurately recording network failures, identifying the type of network element involved, the root cause of the problem, and the time to repair the fault. Recognizing the limitations of available methods, it became obvious that another approach of determining network availability had to be defined. The chosen concept involved the periodic sampling of network services and applications from various network locations. A measure of ''network'' availability was then calculated based on the ratio of polling success to failure. The effort required to gather the information and produce a useful metric is not prohibitive and the information gained has verified long held feelings regarding network performance with real data

  3. FY 1998 annual summary report on International Clean Energy Network Using Hydrogen Conversion (WE-NET) system technology. Subtask 2. Examination and promotion of measures to obtain international understanding and cooperation; 1998 nendo seika hokokusho. Suiso riyo kokusai clean energy system gijutsu (WE-NET) subtask 2 (kokusai kyoryoku shuishin no tame no chosa kento)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    Described herein are the results of examination and promotion of measures to obtain international understanding and cooperation, and examination and development of measures to promote international exchange of technical information, conducted in the FY 1998 continuously from the previous year, with the object to realize the International Clean Energy Network Using Hydrogen Conversion (WE-NET) project. In the FY 1998, the English version of the 1997 annual summary report was distributed to a total of about 150 overseas organizations. The WE-NET project activities were presented to the 12th World Hydrogen Energy Conference, International Joint Power Generation Conference held in 1998 by American Society of Mechanical Engineers, and 2nd International Symposium on Advanced Energy Conversion Systems and Related Technologies. For the examination and development of measures to promote international exchange of technical information, the contracting party of Japan for the Hydrogen Implementation Agreement with IEA has been shifted from the government of Japan to NEDO. NEDO has been representing Japan for various workshops on the tasks. The hydrogen projects conducted by Germany and USA were also surveyed. The WE-NET project homepage was opened in June, 1998. (NEDO)

  4. Design and Development of a Pressure Transmitter Using Modified Inductance Measuring Network and Bellow Sensor

    OpenAIRE

    Venkata Lakshmi Narayana K.; Bhujanga Rao A.

    2013-01-01

    In this paper, a pressure transmitter using a modified op-amp based network for inductance measurement using a bellow as sensor has been proposed to measure the pressure and to convert pressure changes in to an electrical current which can be transmitted to a remote indicator. The change in inductance due to change in pressure is measured by an improved modified operational amplifier based network. The proposed network permits offset inductance compensation of sensing coil and also minimizes ...

  5. Comparison of Neural Network Error Measures for Simulation of Slender Marine Structures

    DEFF Research Database (Denmark)

    Christiansen, Niels H.; Voie, Per Erlend Torbergsen; Winther, Ole

    2014-01-01

    Training of an artificial neural network (ANN) adjusts the internal weights of the network in order to minimize a predefined error measure. This error measure is given by an error function. Several different error functions are suggested in the literature. However, the far most common measure...

  6. Physiological measurement platform using wireless network with Android application

    Directory of Open Access Journals (Sweden)

    Swagata Devi

    Full Text Available Currently, many people suffer from arrhythmia or hypoxia, which are abnormal health conditions. Arrhythmia occurs when a person has an irregular or abnormal heart rate, while hypoxia is realized when there is a deficiency in oxygen reaching the tissues. When a person suffers from arrhythmia, there is the possibility that the person has cardiovascular disease. A low oxygen level eventually leads to organ failure, which can result in death. To prevent such conditions, a mobile physiological measurement platform has been proposed in this paper. This system will continuously monitor the heart rate and the oxygen level of a patient. The proposed system is mainly beneficial because the medical staff or the caregiver can provide care to patients without being in close proximity. In this way, multiple numbers of patients can be treated by the physician at the same time. In this paper, two main physiological signals: the electrocardiogram (ECG and the photoplethysmogram (PPG are recorded, to measure the heart rate (in beats per minute and the peripheral capillary oxygen saturation level or SpO2 (in percentage of the patient. This is done by using a convenient graphical user interface (GUI in the Matrix Laboratory (MATLAB. Pre-processing of the bio-medical signals is done in the GUI and the calculated results are saved as text files in the current directory of MATLAB. We further propose an Android application, which will display the physiological parameters after the text files have been accessed via a wireless network. The heart rate and the oxygen level can both be monitored via this application. In case the results show an abnormal reading, the physician is notified immediately via text messaging. Keywords: ECG, PPG, SpO2, GUI, MATLAB, Android, Android App

  7. A Bayesian Approach to Measurement Bias in Networking Studies

    NARCIS (Netherlands)

    Zhu, Ling; Robinson, Scott E.; Torenvlied, René

    2014-01-01

    The study of managerial networking has been growing in the field of public administration; a field that analyzes how managers in open system organizations interact with different external actors and organizations. Coincident with this interest in managerial networking is the use of self-reported

  8. GFT centrality: A new node importance measure for complex networks

    Science.gov (United States)

    Singh, Rahul; Chakraborty, Abhishek; Manoj, B. S.

    2017-12-01

    Identifying central nodes is very crucial to design efficient communication networks or to recognize key individuals of a social network. In this paper, we introduce Graph Fourier Transform Centrality (GFT-C), a metric that incorporates local as well as global characteristics of a node, to quantify the importance of a node in a complex network. GFT-C of a reference node in a network is estimated from the GFT coefficients derived from the importance signal of the reference node. Our study reveals the superiority of GFT-C over traditional centralities such as degree centrality, betweenness centrality, closeness centrality, eigenvector centrality, and Google PageRank centrality, in the context of various arbitrary and real-world networks with different degree-degree correlations.

  9. Completely random measures for modelling block-structured sparse networks

    DEFF Research Database (Denmark)

    Herlau, Tue; Schmidt, Mikkel Nørgaard; Mørup, Morten

    2016-01-01

    Many statistical methods for network data parameterize the edge-probability by attributing latent traits to the vertices such as block structure and assume exchangeability in the sense of the Aldous-Hoover representation theorem. Empirical studies of networks indicate that many real-world networks...... have a power-law distribution of the vertices which in turn implies the number of edges scale slower than quadratically in the number of vertices. These assumptions are fundamentally irreconcilable as the Aldous-Hoover theorem implies quadratic scaling of the number of edges. Recently Caron and Fox...

  10. Measuring sustainable accessibility potential using the mobility infrastructure's network configuration

    NARCIS (Netherlands)

    Gil, J.; Read, S.

    2012-01-01

    This paper is an exploration into the analysis of public transport networks using space syntax approaches combined with concepts of sustainable accessibility. Present urban development policy aims to achieve sustainable mobility patterns, shifting mobility to soft transportation modes such as

  11. Optimizing bulk data transfers using network measurements: A practical case

    International Nuclear Information System (INIS)

    Ciuffoletti, A; Merola, L; Palmieri, F; Russo, G; Pardi, S

    2010-01-01

    In modern Data Grid infrastructures, we increasingly face the problem of providing the running applications with fast and reliable access to large data volumes, often geographically distributed across the network. As a direct consequence, the concept of replication has been adopted by the grid community to increase data availability and maximize job throughput. To be really effective, such process has to be driven by specific optimization strategies that define when and where replicas should be created or deleted on a per-site basis, and which replicas a job should use. These strategies have to take into account the available network bandwidth as a primary resource, prior to any consideration about storage or processing power. We present a novel replica management service, integrated within the Gluedomains active network monitoring architecture, designed and implemented within the centralized collective middleware framework of the SCoPE project to provide network-aware transfer services for data intensive Grid applications.

  12. Valuation of measurement data for low voltage network expansion planning

    NARCIS (Netherlands)

    Nijhuis, M.; Gibescu, M.; Cobben, J.F.G.

    2017-01-01

    The introduction of electric vehicles and photovoltaics is changing the residential electricity consumption. Distribution network operators (DNO) are investing in an advanced metering infrastructure (AMI) to enable cost reduction through smart grid applications. The DNO also benefits from the

  13. Air Quality Measures on the National Environmental Health Tracking Network

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Environmental Protection Agency (EPA) provides air pollution data about ozone and particulate matter (PM2.5) to CDC for the Tracking Network. The EPA maintains a...

  14. Software network analyzer for computer network performance measurement planning over heterogeneous services in higher educational institutes

    OpenAIRE

    Ismail, Mohd Nazri

    2009-01-01

    In 21st century, convergences of technologies and services in heterogeneous environment have contributed multi-traffic. This scenario will affect computer network on learning system in higher educational Institutes. Implementation of various services can produce different types of content and quality. Higher educational institutes should have a good computer network infrastructure to support usage of various services. The ability of computer network should consist of i) higher bandwidth; ii) ...

  15. Testing the Feasibility of a Low-Cost Network Performance Measurement Infrastructure

    Energy Technology Data Exchange (ETDEWEB)

    Chevalier, Scott [Indiana Univ., Bloomington, IN (United States). International Networks; Schopf, Jennifer M. [Indiana Univ., Bloomington, IN (United States). International Networks; Miller, Kenneth [Pennsylvania State Univ., University Park, PA (United States). Telecommunications and Networking Services; Zurawski, Jason [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Sciences Network

    2016-07-01

    Todays science collaborations depend on reliable, high performance networks, but monitoring the end-to-end performance of a network can be costly and difficult. The most accurate approaches involve using measurement equipment in many locations, which can be both expensive and difficult to manage due to immobile or complicated assets. The perfSONAR framework facilitates network measurement making management of the tests more reasonable. Traditional deployments have used over-provisioned servers, which can be expensive to deploy and maintain. As scientific network uses proliferate, there is a desire to instrument more facets of a network to better understand trends. This work explores low cost alternatives to assist with network measurement. Benefits include the ability to deploy more resources quickly, and reduced capital and operating expenditures. Finally, we present candidate platforms and a testing scenario that evaluated the relative merits of four types of small form factor equipment to deliver accurate performance measurements.

  16. Evaluation of Techniques to Detect Significant Network Performance Problems using End-to-End Active Network Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Cottrell, R.Les; Logg, Connie; Chhaparia, Mahesh; /SLAC; Grigoriev, Maxim; /Fermilab; Haro, Felipe; /Chile U., Catolica; Nazir, Fawad; /NUST, Rawalpindi; Sandford, Mark

    2006-01-25

    End-to-End fault and performance problems detection in wide area production networks is becoming increasingly hard as the complexity of the paths, the diversity of the performance, and dependency on the network increase. Several monitoring infrastructures are built to monitor different network metrics and collect monitoring information from thousands of hosts around the globe. Typically there are hundreds to thousands of time-series plots of network metrics which need to be looked at to identify network performance problems or anomalous variations in the traffic. Furthermore, most commercial products rely on a comparison with user configured static thresholds and often require access to SNMP-MIB information, to which a typical end-user does not usually have access. In our paper we propose new techniques to detect network performance problems proactively in close to realtime and we do not rely on static thresholds and SNMP-MIB information. We describe and compare the use of several different algorithms that we have implemented to detect persistent network problems using anomalous variations analysis in real end-to-end Internet performance measurements. We also provide methods and/or guidance for how to set the user settable parameters. The measurements are based on active probes running on 40 production network paths with bottlenecks varying from 0.5Mbits/s to 1000Mbit/s. For well behaved data (no missed measurements and no very large outliers) with small seasonal changes most algorithms identify similar events. We compare the algorithms' robustness with respect to false positives and missed events especially when there are large seasonal effects in the data. Our proposed techniques cover a wide variety of network paths and traffic patterns. We also discuss the applicability of the algorithms in terms of their intuitiveness, their speed of execution as implemented, and areas of applicability. Our encouraging results compare and evaluate the accuracy of our

  17. Energy and Power Measurements for Network Coding in the Context of Green Mobile Clouds

    DEFF Research Database (Denmark)

    Paramanathan, Achuthan; Pedersen, Morten Videbæk; Roetter, Daniel Enrique Lucani

    2013-01-01

    results for inter-session network coding in Open-Mesh routers underline that the energy invested in performing network coding pays off by dramatically reducing the total energy for the transmission of data over wireless links. We also show measurements for intra-session network coding in three different......This paper presents an in-depth power and energy measurement campaign for inter- and intra-session network coding enabled communication in mobile clouds. The measurements are carried out on different commercial platforms with focus on routers and mobile phones with different CPU capabilities. Our...

  18. Measurements of Voltage Harmonics in 400 kV Transmission Network

    Directory of Open Access Journals (Sweden)

    Ryszard Pawełek

    2014-06-01

    Full Text Available The paper deals with the analysis of voltage harmonics measurements performed in the 400 kV transmission network. The voltage was measured by means of three transducers: resistive voltage divider, inductive measuring transformer and capacitive voltage measuring transformer. Instrument errors were estimated for measuring transformers with reference to the harmonic values obtained from the voltage divider.

  19. Talking and learning physics: Predicting future grades from network measures and Force Concept Inventory pretest scores

    Directory of Open Access Journals (Sweden)

    Jesper Bruun

    2013-07-01

    Full Text Available The role of student interactions in learning situations is a foundation of sociocultural learning theory, and social network analysis can be used to quantify student relations. We discuss how self-reported student interactions can be viewed as processes of meaning making and use this to understand how quantitative measures that describe the position in a network, called centrality measures, can be understood in terms of interactions that happen in the context of a university physics course. We apply this discussion to an empirical data set of self-reported student interactions. In a weekly administered survey, first year university students enrolled in an introductory physics course at a Danish university indicated with whom they remembered having communicated within different interaction categories. For three categories pertaining to (1 communication about how to solve physics problems in the course (called the PS category, (2 communications about the nature of physics concepts (called the CD category, and (3 social interactions that are not strictly related to the content of the physics classes (called the ICS category in the introductory mechanics course, we use the survey data to create networks of student interaction. For each of these networks, we calculate centrality measures for each student and correlate these measures with grades from the introductory course, grades from two subsequent courses, and the pretest Force Concept Inventory (FCI scores. We find highly significant correlations (p<0.001 between network centrality measures and grades in all networks. We find the highest correlations between network centrality measures and future grades. In the network composed of interactions regarding problem solving (the PS network, the centrality measures hide and PageRank show the highest correlations (r=-0.32 and r=0.33, respectively with future grades. In the CD network, the network measure target entropy shows the highest correlation

  20. Incentivizing and Evaluating Internet-Wide Network Measurements

    Science.gov (United States)

    2014-03-01

    Romania . . . . . . . . . . . . . . . . . . . . . . 62 Figure A.20 Cumulative SCR for Egypt . . . . . . . . . . . . . . . . . . . . . . . 63 Figure A...defined in RFC 1918 [29] and these packets should never be routed in the public Internet. These packets, however, are often filtered in the network core...Turkey, Singapore, Russia, Romania , Pakistan, Philippines, Netherlands, Indonesia, Hun- gary, Guatemala, Finland, Denmark, Switzerland, Brazil

  1. Quantum Measurements: From Bayes Rule to Neural Networks

    DEFF Research Database (Denmark)

    Greplova, Eliska

    2017-01-01

    Quantum technologies are becoming more and more introduced into the devices that we use in the daily life, such as quantum dot based television screens or quantum cryptographic channels for encoding financial transactions. Given the limits of the silicon computer chips, it will in the near future...... learning techniques such as artificial neural networks....

  2. Security measures effect over performance in service provider network

    African Journals Online (AJOL)

    pc

    2018-03-05

    Mar 5, 2018 ... Abstract—network security is defined as a set of policies and actions taken by a ... These threats are linked with the following factors that are ... typically smaller than those in the service provider space. ... Service providers cannot manage to provide ... e the DB performance effect ... r the business needs [10].

  3. Facing a Problem of Electrical Energy Quality in Ship Networks-measurements, Estimation, Control

    Institute of Scientific and Technical Information of China (English)

    Tomasz Tarasiuk; Janusz Mindykowski; Xiaoyan Xu

    2003-01-01

    In this paper, electrical energy quality and its indices in ship electric networks are introduced, especially the meaning of electrical energy quality terms in voltage and active and reactive power distribution indices. Then methods of measurement of marine electrical energy indices are introduced in details and a microprocessor measurement-diagnosis system with the function of measurement and control is designed. Afterwards, estimation and control of electrical power quality of marine electrical power networks are introduced. And finally, according to the existing method of measurement and control of electrical power quality in ship power networks, the improvement of relative method is proposed.

  4. An Attractor-Based Complexity Measurement for Boolean Recurrent Neural Networks

    Science.gov (United States)

    Cabessa, Jérémie; Villa, Alessandro E. P.

    2014-01-01

    We provide a novel refined attractor-based complexity measurement for Boolean recurrent neural networks that represents an assessment of their computational power in terms of the significance of their attractor dynamics. This complexity measurement is achieved by first proving a computational equivalence between Boolean recurrent neural networks and some specific class of -automata, and then translating the most refined classification of -automata to the Boolean neural network context. As a result, a hierarchical classification of Boolean neural networks based on their attractive dynamics is obtained, thus providing a novel refined attractor-based complexity measurement for Boolean recurrent neural networks. These results provide new theoretical insights to the computational and dynamical capabilities of neural networks according to their attractive potentialities. An application of our findings is illustrated by the analysis of the dynamics of a simplified model of the basal ganglia-thalamocortical network simulated by a Boolean recurrent neural network. This example shows the significance of measuring network complexity, and how our results bear new founding elements for the understanding of the complexity of real brain circuits. PMID:24727866

  5. Measuring the Influence of Efficient Ports using Social Network Metrics

    Directory of Open Access Journals (Sweden)

    Byung-Hak Leem

    2015-02-01

    Full Text Available Data envelopment analysis (DEA is known as a useful tool that produces many efficient decision-making units (DMUs. Traditional DEA provides relative efficient scores and reference sets, but does not influence and rank the efficient DMUs. This paper suggests a method that provides influence and ranking information by using PageRank as a centrality of Social Network analysis (SNA based on reference sets and their lambda values. The social network structure expresses the DMU as a node, reference sets as link, and lambda as connection strengths or weights. This paper, with PageRank, compares the Eigenvector centrality suggested by Liu, et al. in 2009, and shows that PageRank centrality is more accurate.

  6. Measuring Customer Behavior with Deep Convolutional Neural Networks

    Directory of Open Access Journals (Sweden)

    Veaceslav Albu

    2016-03-01

    Full Text Available In this paper, we propose a neural network model for human emotion and gesture classification. We demonstrate that the proposed architecture represents an effective tool for real-time processing of customer's behavior for distributed on-land systems, such as information kiosks, automated cashiers and ATMs. The proposed approach combines most recent biometric techniques with the neural network approach for real-time emotion and behavioral analysis. In the series of experiments, emotions of human subjects were recorded, recognized, and analyzed to give statistical feedback of the overall emotions of a number of targets within a certain time frame. The result of the study allows automatic tracking of user’s behavior based on a limited set of observations.

  7. Basic security measures for IEEE 802.11 wireless networks

    Directory of Open Access Journals (Sweden)

    Oscar P. Sarmiento

    2008-05-01

    Full Text Available This article presents a tutorial/discussion of three commonly-used IEEE 802.11 wireless network security standards: WEP, WPA and WPA2. A detailed analysis of the RC4 algorithm supporting WEP is presented, including its vulnera-bilities. The WPA and WPA2 encryption protocols’ most relevant aspects and technical characteristics are reviewed for a comparative analysis of the three standards in terms of the security they provide. Special attention has been paid to WEP encryption by using an educational simulation tool written in C++ Builder for facilitating the unders-tanding of this protocol at academic level. Two practical cases of wireless security configurations using Cisco net-working equipment are also presented: configuring and enabling WPA-Personal and WPA2-Personal (these being security options used by TKIP and AES, respectively.

  8. Basic security measures for IEEE 802.11 wireless networks

    OpenAIRE

    Sarmiento, Oscar P.; Guerrero, Fabio G.; Rey Argote, David

    2008-01-01

    This article presents a tutorial/discussion of three commonly-used IEEE 802.11 wireless network security standards: WEP, WPA and WPA2. A detailed analysis of the RC4 algorithm supporting WEP is presented, including its vulnerabilities. The WPA and WPA2 encryption protocols’ most relevant aspects and technical characteristics are reviewed for a comparative analysis of the three standards in terms of the security they provide. Special attention has been paid to WEP encryption by using an educat...

  9. Acquisition Research Program Homepage

    OpenAIRE

    2015-01-01

    Includes an image of the main page on this date and compressed file containing additional web pages. Established in 2003, Naval Postgraduate School’s (NPS) Acquisition Research Program provides leadership in innovation, creative problem solving and an ongoing dialogue, contributing to the evolution of Department of Defense acquisition strategies.

  10. Air Force Academy Homepage

    Science.gov (United States)

    Communications Focal Point Contracting Squadron Force Support Squadron Mortuary Affairs Logistics Readiness Squadron Cadet Logistics Deployment and Distribution Material Management Operations PM Equipment Lab

  11. AVERT - Tutorial Homepage

    Science.gov (United States)

    Find the index of Training Modules for AVERT, with instructions for using the training and what you'll need. AVERT can be used to estimate the potential of energy efficiency and renewable energy programs to reduce air pollution.

  12. Home sweet homepage

    Science.gov (United States)

    2010-09-01

    The importance of an up to date and easy to find website should not be underestimated by scientists looking to establish links to others in their community - and represents good value for relatively little effort.

  13. Division of Finance Homepage

    Science.gov (United States)

    Top Department of Administration logo Alaska Department of Administration Division of Finance Search Search the Division of Finance site DOF State of Alaska Finance Home Content Area Accounting Charge Cards You are here Administration / Finance Division of Finance Updates IRIS Expenditure Object Codes

  14. High resistance (up to 1014 ohms) measurement using RC networks

    International Nuclear Information System (INIS)

    Florescu, Valeriu

    2008-01-01

    An application of dynamic measuring techniques of resistances from 10 6 to 10 14 ohms is described. The method has been analyzed with an eye to measuring accuracy, other influences of the actual measuring circuit also being considered. In conclusion, an automatic measuring method with A/D conversion, automatic range selection, and digital output in semilogarithmic form is outlined. It has been experimentally verified that the dynamic method of resistance measurement can be used for testing insulation resistance of materials and resistors. The great advantage of the automatic measuring circuit is that, apart from an easy automatic selection of the measuring range, digital output in semilogarithmic form ensures compatibility with digital computer systems and facilitates the grading in resistor manufacture. The time required for measuring resistances of the known order of magnitude does not exceed 1 s. Automatic selection of the order of magnitude speeds up the measurement of unknown resistances. For resistance measurement over the range of 10 6 to 10 14 ohms, the measuring accuracy of 1 to 2% is usually sufficient. The meter can be designed as an inexpensive attachment to a conventional counter. The principle of integration measurement avoids undesirable interference effects with which the conventional measuring methods are afflicted. Since the measuring voltage can be adjusted continuously, even the voltage dependence of resistance can be measured

  15. Simulation and measurement of optical access network with different types of optical-fiber amplifiers

    Science.gov (United States)

    Latal, Jan; Vogl, Jan; Koudelka, Petr; Vitasek, Jan; Siska, Petr; Liner, Andrej; Papes, Martin; Vasinek, Vladimir

    2012-01-01

    The optical access networks are nowadays swiftly developing in the telecommunications field. These networks can provide higher data transfer rates, and have great potential to the future in terms of transmission possibilities. Many local internet providers responded to these facts and began gradually installing optical access networks into their originally built networks, mostly based on wireless communication. This allowed enlargement of possibilities for end-users in terms of high data rates and also new services such as Triple play, IPTV (Internet Protocol television) etc. However, with this expansion and building-up is also related the potential of reach in case of these networks. Big cities, such as Prague, Brno, Ostrava or Olomouc cannot be simply covered, because of their sizes and also because of their internal regulations given by various organizations in each city. Standard logical and also physical reach of EPON (IEEE 802.3ah - Ethernet Passive Optical Network) optical access network is about 20 km. However, for networks based on Wavelength Division Multiplex the reach can be up to 80 km, if the optical-fiber amplifier is inserted into the network. This article deals with simulation of different types of amplifiers for WDM-PON (Wavelength Division Multiplexing-Passive Optical Network) network in software application Optiwave OptiSystem and than are the values from the application and from real measurement compared.

  16. An assessment of available measures to reduce traction energy use in railway networks

    International Nuclear Information System (INIS)

    Douglas, Heather; Roberts, Clive; Hillmansen, Stuart; Schmid, Felix

    2015-01-01

    Highlights: • Railway networks are defined in terms of their distinguishing features. • Current energy saving measures are reviewed and categorised by the energy use they target. • The achievable energy savings of different measures are compared dependent on the network type. • The success of a measure depends on the characteristics of the network, vehicle and service. • Measures should be evaluated at system level due to interdependencies. - Abstract: Rail is becoming an increasingly popular choice to satisfy transportation demands locally, nationally and internationally, due to its inherent efficiency and high capacity. Despite this, operators are facing pressure to reduce rail energy consumption to meet efficiency targets, whilst still maintaining service quality and managing increased demand. A number of individual measures have been proposed to reduce energy in the rail sector, often showing good results on specific case studies. It is generally agreed that the attainable savings of a given measure change dependant on the route, vehicle and service characteristics. However, there is little information in the literature specifically regarding which measures are most suitable for given network types, or how they interact. This paper therefore aims to begin evaluating the available measures in terms of their suitability for different systems. Firstly, networks are defined in terms of their distinguishing features. As traction accounts for the majority of all energy use in the rail sector, the traction flow through a vehicle is considered as the starting point for an evaluation of measures. Current technologies and procedures are reviewed and categorised based on which area of traction use they target. Thought is given to the factors that affect implementation and the networks where they are applied. A key output of this paper is a comparison of the achievable energy savings of different measures dependent on the network type. It is hoped that this will

  17. Network centrality measures and systemic risk: An application to the Turkish financial crisis

    Science.gov (United States)

    Kuzubaş, Tolga Umut; Ömercikoğlu, Inci; Saltoğlu, Burak

    2014-07-01

    In this paper, we analyze the performance of several network centrality measures in detecting systemically important financial institutions (SIFI) using data from the Turkish Interbank market during the financial crisis in 2000. We employ various network investigation tools such as volume, transactions, links, connectivity and reciprocity to gain a clearer picture of the network topology of the interbank market. We study the main borrower role of Demirbank in the crash of the banking system with network centrality measures which are extensively used in the network theory. This ex-post analysis of the crisis shows that centrality measures perform well in identifying and monitoring systemically important financial institutions which provide useful insights for financial regulations.

  18. Dynamical networks: Finding, measuring, and tracking neural population activity using network science

    Directory of Open Access Journals (Sweden)

    Mark D. Humphries

    2017-12-01

    Full Text Available Systems neuroscience is in a headlong rush to record from as many neurons at the same time as possible. As the brain computes and codes using neuron populations, it is hoped these data will uncover the fundamentals of neural computation. But with hundreds, thousands, or more simultaneously recorded neurons come the inescapable problems of visualizing, describing, and quantifying their interactions. Here I argue that network science provides a set of scalable, analytical tools that already solve these problems. By treating neurons as nodes and their interactions as links, a single network can visualize and describe an arbitrarily large recording. I show that with this description we can quantify the effects of manipulating a neural circuit, track changes in population dynamics over time, and quantitatively define theoretical concepts of neural populations such as cell assemblies. Using network science as a core part of analyzing population recordings will thus provide both qualitative and quantitative advances to our understanding of neural computation.

  19. Measurement campaign on connectivity of mesh networks formed by mobile devices

    DEFF Research Database (Denmark)

    Pietrarca, Beatrice; Sasso, Giovanni; Perrucci, Gian Paolo

    2007-01-01

    This paper reports the results of a measurement campaign on the connectivity level of mobile devices using Bluetooth (BT) to form cooperative mobile mesh networks. Such mobile mesh networks composed of mobile devices are the basis for any peer-to-peer communication like wireless grids or social...

  20. Air pollution assessment in the Slovak Republic in 2005. Measurement stations of air quality monitoring network

    International Nuclear Information System (INIS)

    Anon

    2006-05-01

    In this Appendix to the report 'Air pollution assessment in the Slovak Republic in 2005' the main characteristics of measurement stations of air quality monitoring network of the Slovak Republic are presented

  1. Air pollution assessment in the Slovak Republic in 2004. Measurement stations of air quality monitoring network

    International Nuclear Information System (INIS)

    Anon

    2005-07-01

    In this Appendix to the report 'Air pollution assessment in the Slovak Republic in 2004' the main characteristics of measurement stations of air quality monitoring network of the Slovak Republic are presented

  2. Output power distributions of mobile radio base stations based on network measurements

    International Nuclear Information System (INIS)

    Colombi, D; Thors, B; Persson, T; Törnevik, C; Wirén, N; Larsson, L-E

    2013-01-01

    In this work output power distributions of mobile radio base stations have been analyzed for 2G and 3G telecommunication systems. The approach is based on measurements in selected networks using performance surveillance tools part of the network Operational Support System (OSS). For the 3G network considered, direct measurements of output power levels were possible, while for the 2G networks, output power levels were estimated from measurements of traffic volumes. Both voice and data services were included in the investigation. Measurements were conducted for large geographical areas, to ensure good overall statistics, as well as for smaller areas to investigate the impact of different environments. For high traffic hours, the 90th percentile of the averaged output power was found to be below 65% and 45% of the available output power for the 2G and 3G systems, respectively.

  3. Output power distributions of mobile radio base stations based on network measurements

    Science.gov (United States)

    Colombi, D.; Thors, B.; Persson, T.; Wirén, N.; Larsson, L.-E.; Törnevik, C.

    2013-04-01

    In this work output power distributions of mobile radio base stations have been analyzed for 2G and 3G telecommunication systems. The approach is based on measurements in selected networks using performance surveillance tools part of the network Operational Support System (OSS). For the 3G network considered, direct measurements of output power levels were possible, while for the 2G networks, output power levels were estimated from measurements of traffic volumes. Both voice and data services were included in the investigation. Measurements were conducted for large geographical areas, to ensure good overall statistics, as well as for smaller areas to investigate the impact of different environments. For high traffic hours, the 90th percentile of the averaged output power was found to be below 65% and 45% of the available output power for the 2G and 3G systems, respectively.

  4. Social climber attachment in forming networks produces a phase transition in a measure of connectivity

    Science.gov (United States)

    Taylor, Dane; Larremore, Daniel B.

    2012-09-01

    The formation and fragmentation of networks are typically studied using percolation theory, but most previous research has been restricted to studying a phase transition in cluster size, examining the emergence of a giant component. This approach does not study the effects of evolving network structure on dynamics that occur at the nodes, such as the synchronization of oscillators and the spread of information, epidemics, and neuronal excitations. We introduce and analyze an alternative link-formation rule, called social climber (SC) attachment, that may be combined with arbitrary percolation models to produce a phase transition using the largest eigenvalue of the network adjacency matrix as the order parameter. This eigenvalue is significant in the analyses of many network-coupled dynamical systems in which it measures the quality of global coupling and is hence a natural measure of connectivity. We highlight the important self-organized properties of SC attachment and discuss implications for controlling dynamics on networks.

  5. A game theory-based trust measurement model for social networks.

    Science.gov (United States)

    Wang, Yingjie; Cai, Zhipeng; Yin, Guisheng; Gao, Yang; Tong, Xiangrong; Han, Qilong

    2016-01-01

    In social networks, trust is a complex social network. Participants in online social networks want to share information and experiences with as many reliable users as possible. However, the modeling of trust is complicated and application dependent. Modeling trust needs to consider interaction history, recommendation, user behaviors and so on. Therefore, modeling trust is an important focus for online social networks. We propose a game theory-based trust measurement model for social networks. The trust degree is calculated from three aspects, service reliability, feedback effectiveness, recommendation credibility, to get more accurate result. In addition, to alleviate the free-riding problem, we propose a game theory-based punishment mechanism for specific trust and global trust, respectively. We prove that the proposed trust measurement model is effective. The free-riding problem can be resolved effectively through adding the proposed punishment mechanism.

  6. The impact of measurement errors in the identification of regulatory networks

    Directory of Open Access Journals (Sweden)

    Sato João R

    2009-12-01

    Full Text Available Abstract Background There are several studies in the literature depicting measurement error in gene expression data and also, several others about regulatory network models. However, only a little fraction describes a combination of measurement error in mathematical regulatory networks and shows how to identify these networks under different rates of noise. Results This article investigates the effects of measurement error on the estimation of the parameters in regulatory networks. Simulation studies indicate that, in both time series (dependent and non-time series (independent data, the measurement error strongly affects the estimated parameters of the regulatory network models, biasing them as predicted by the theory. Moreover, when testing the parameters of the regulatory network models, p-values computed by ignoring the measurement error are not reliable, since the rate of false positives are not controlled under the null hypothesis. In order to overcome these problems, we present an improved version of the Ordinary Least Square estimator in independent (regression models and dependent (autoregressive models data when the variables are subject to noises. Moreover, measurement error estimation procedures for microarrays are also described. Simulation results also show that both corrected methods perform better than the standard ones (i.e., ignoring measurement error. The proposed methodologies are illustrated using microarray data from lung cancer patients and mouse liver time series data. Conclusions Measurement error dangerously affects the identification of regulatory network models, thus, they must be reduced or taken into account in order to avoid erroneous conclusions. This could be one of the reasons for high biological false positive rates identified in actual regulatory network models.

  7. Reward networks in the brain as captured by connectivity measures

    Directory of Open Access Journals (Sweden)

    Estela Camara

    2009-12-01

    Full Text Available An assortment of human behaviors is thought to be driven by rewards including reinforcement learning, novelty processing, learning, decision making, economic choice, incentive motivation, and addiction. In each case the ventral tegmental area / ventral striatum (Nucleus accumbens system (VTA-VS has been implicated as a key structure by functional imaging studies, mostly on the basis of standard, univariate analyses. Here we propose that standard fMRI analysis needs to be complemented by methods that take into account the differential connectivity of the VTA-VS system in the different behavioral contexts in order to describe reward based processes more appropriately. We first consider the wider network for reward processing as it emerged from animal experimentation. Subsequently, an example for a method to assess functional connectivity is given. Finally, we illustrate the usefulness of such analyses by examples regarding reward valuation, reward expectation and the role of reward in addiction.

  8. Know Thyself: Metacognitive Networks and Measures of Consciousness

    Science.gov (United States)

    Pasquali, Antoine; Timmermans, Bert; Cleeremans, Axel

    2010-01-01

    Subjective measures of awareness rest on the assumption that conscious knowledge is knowledge that participants know they possess. Post-Decision Wagering (PDW), recently proposed as a new measure of awareness, requires participants to place a high or a low wager on their decisions. Whereas advantageous wagering indicates awareness of the knowledge…

  9. Network module detection: Affinity search technique with the multi-node topological overlap measure.

    Science.gov (United States)

    Li, Ai; Horvath, Steve

    2009-07-20

    Many clustering procedures only allow the user to input a pairwise dissimilarity or distance measure between objects. We propose a clustering method that can input a multi-point dissimilarity measure d(i1, i2, ..., iP) where the number of points P can be larger than 2. The work is motivated by gene network analysis where clusters correspond to modules of highly interconnected nodes. Here, we define modules as clusters of network nodes with high multi-node topological overlap. The topological overlap measure is a robust measure of interconnectedness which is based on shared network neighbors. In previous work, we have shown that the multi-node topological overlap measure yields biologically meaningful results when used as input of network neighborhood analysis. We adapt network neighborhood analysis for the use of module detection. We propose the Module Affinity Search Technique (MAST), which is a generalized version of the Cluster Affinity Search Technique (CAST). MAST can accommodate a multi-node dissimilarity measure. Clusters grow around user-defined or automatically chosen seeds (e.g. hub nodes). We propose both local and global cluster growth stopping rules. We use several simulations and a gene co-expression network application to argue that the MAST approach leads to biologically meaningful results. We compare MAST with hierarchical clustering and partitioning around medoid clustering. Our flexible module detection method is implemented in the MTOM software which can be downloaded from the following webpage: http://www.genetics.ucla.edu/labs/horvath/MTOM/

  10. A Step towards Developing a Sustainability Performance Measure within Industrial Networks

    Directory of Open Access Journals (Sweden)

    Samaneh Shokravi

    2014-04-01

    Full Text Available Despite the plethora of literature in sustainability and supply chain management in the recent years, a quantitative tool that measures the sustainability performance of an industrial supply network, considering the uncertainties of existing data, is hard to find. This conceptual paper is aimed at establishing a quantitative measure for the sustainability performance of industrial supply networks that considers aleatory and epistemic uncertainties in its environmental performance evaluation. The measure is built upon economic, environmental and social performance evaluation models. These models address a number of shortcomings in the literature, such as incomplete and inaccurate calculation of environmental impacts, as well as the disregard for aleatory and epistemic uncertainties in the input data and, more importantly, the scarce number of quantitative social sustainability measures. Dyadic interactions are chosen for the network, while the network members have a revenue-sharing relationship. This relationship promotes sharing of the required information for the use of the proposed model. This measure provides an approach to quantify the environmental, social and economic sustainability performances of a supply network. Moreover, as this measure is not specifically designed for an industrial sector, it can be employed over an evolving and diverse industrial network.

  11. Procedure to Solve Network DEA Based on a Virtual Gap Measurement Model

    Directory of Open Access Journals (Sweden)

    Fuh-hwa Franklin Liu

    2017-01-01

    Full Text Available Network DEA models assess production systems that contain a set of network-structured subsystems. Each subsystem has input and output measures from and to the external network and has intermediate measures that link to other subsystems. Most published studies demonstrate how to employ DEA models to establish network DEA models. Neither static nor dynamic network DEA models adjust the links. This paper applies the virtual gap measurement (VGM model to construct a mixed integer program to solve dynamic network DEA problems. The mixed integer program sets the total numbers of “as-input” and “as-output” equal to the total number of links in the objective function. To obtain the best-practice efficiency, each DMU determines a set of weights for inputs, outputs, and links. The links are played either “as-input” or “as-output.” Input and as-input measures reduce slack, whereas output and as-output measures increase slacks to attain their target on the production frontier.

  12. Local difference measures between complex networks for dynamical system model evaluation.

    Science.gov (United States)

    Lange, Stefan; Donges, Jonathan F; Volkholz, Jan; Kurths, Jürgen

    2015-01-01

    A faithful modeling of real-world dynamical systems necessitates model evaluation. A recent promising methodological approach to this problem has been based on complex networks, which in turn have proven useful for the characterization of dynamical systems. In this context, we introduce three local network difference measures and demonstrate their capabilities in the field of climate modeling, where these measures facilitate a spatially explicit model evaluation.Building on a recent study by Feldhoff et al. [8] we comparatively analyze statistical and dynamical regional climate simulations of the South American monsoon system [corrected]. types of climate networks representing different aspects of rainfall dynamics are constructed from the modeled precipitation space-time series. Specifically, we define simple graphs based on positive as well as negative rank correlations between rainfall anomaly time series at different locations, and such based on spatial synchronizations of extreme rain events. An evaluation against respective networks built from daily satellite data provided by the Tropical Rainfall Measuring Mission 3B42 V7 reveals far greater differences in model performance between network types for a fixed but arbitrary climate model than between climate models for a fixed but arbitrary network type. We identify two sources of uncertainty in this respect. Firstly, climate variability limits fidelity, particularly in the case of the extreme event network; and secondly, larger geographical link lengths render link misplacements more likely, most notably in the case of the anticorrelation network; both contributions are quantified using suitable ensembles of surrogate networks. Our model evaluation approach is applicable to any multidimensional dynamical system and especially our simple graph difference measures are highly versatile as the graphs to be compared may be constructed in whatever way required. Generalizations to directed as well as edge- and node

  13. Tariffing of energy measured consumers in the distribution network; Tariffering av energimaalte kunder i distribusjonsnettet

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-12-20

    Criteria for socio-economic effective tariffing of energy-measured clients in the distribution network are discussed (i.e. households, leisure homes and smaller business clients), this means consumers that do not have hourly measurements or effect measurements. The tariffs should be based on variable segments that reflect short-term marginal costs in the network (in practice loss of transfer) and fixed segments that to the least extent possible influence the consumers' decisions in the choice of energy solutions, both in short term and long term. High-priced energy segments and effect based fixed segments may give unfortunate socio-economic price signals compared to the marginal long-term network costs. A fixed segment per measurement unit is in principle completely neutral, but it is to some extent vulnerable to strategic adjustments if the consumers choose collective measurement. This is not necessarily a big problem in practice (author)

  14. Measurement of void fraction distribution in two-phase flow by impedance CT with neural network

    International Nuclear Information System (INIS)

    Hayashi, Hideaki; Sumida, Isao; Sakai, Sinji; Wakai, Kazunori

    1996-01-01

    This paper describes a new method for measurement of void distribution using impedance CT with a hierarchical neural network. The present method consists of four processes. First, output electric currents are calculated by simulation of various distributions of void fraction. The relationship between distribution of void fraction and electric current is called 'teaching data'. Second, the neural network learns the teaching data by the back propagation method. Third, output electric currents are measured about actual two-phase flow. Finally, distribution of void fraction is calculated by the taught neural network using the measured electric currents. In this paper, measurement and learning parameters are adjusted, experimental results obtained using the impedance CT method are compared with data obtained by the impedance probe method. The results show that our method is effective for measurement of void fraction distribution. (author)

  15. Measuring Large-Scale Social Networks with High Resolution

    DEFF Research Database (Denmark)

    Stopczynski, Arkadiusz; Sekara, Vedran; Sapiezynski, Piotr

    2014-01-01

    and research agenda driving the study. Additionally, the paper details the data-types measured, and the technical infrastructure in terms of both backend and phone software, as well as an outline of the deployment procedures. We document the participant privacy procedures and their underlying principles...

  16. Erythemal solar UV measurement network in New Zealand

    International Nuclear Information System (INIS)

    Smith, G.J.

    1993-01-01

    Measured daily total erythemal doses for 1989, 1990 and 1991 were presented and the cloudless-sky daily dose at the autumn equinox was approximately 30-50% higher than at the spring equinox as a result of the seasonal variation in ozone levels. In addition a substantially lower spring equinox erythemal dose was observed in 1991, probably as a result of increased aerosols arising from the Pinatubo eruption. An asymmetry in the diurnal pattern of irradiances about solar noon has been observed on cloudless days. Higher UV irradiances have been usually observed in the afternoons than in the mornings. Measurement of erythemal radiation is needed for skin cancer epidemiology projects. Given the uncertainties relating to the exposure of individuals to solar erythemal radiation, personal dosimeters may be very useful in providing more reliable personal UV exposure data. (author). 4 refs

  17. Recurrence network measures for hypothesis testing using surrogate data: Application to black hole light curves

    Science.gov (United States)

    Jacob, Rinku; Harikrishnan, K. P.; Misra, R.; Ambika, G.

    2018-01-01

    Recurrence networks and the associated statistical measures have become important tools in the analysis of time series data. In this work, we test how effective the recurrence network measures are in analyzing real world data involving two main types of noise, white noise and colored noise. We use two prominent network measures as discriminating statistic for hypothesis testing using surrogate data for a specific null hypothesis that the data is derived from a linear stochastic process. We show that the characteristic path length is especially efficient as a discriminating measure with the conclusions reasonably accurate even with limited number of data points in the time series. We also highlight an additional advantage of the network approach in identifying the dimensionality of the system underlying the time series through a convergence measure derived from the probability distribution of the local clustering coefficients. As examples of real world data, we use the light curves from a prominent black hole system and show that a combined analysis using three primary network measures can provide vital information regarding the nature of temporal variability of light curves from different spectroscopic classes.

  18. Pyramidal resistor networks for electrical impedance tomography with partial boundary measurements

    International Nuclear Information System (INIS)

    Borcea, L; Mamonov, A V; Druskin, V; Vasquez, F Guevara

    2010-01-01

    We introduce an inversion algorithm for electrical impedance tomography (EIT) with partial boundary measurements in two dimensions. It gives stable and fast reconstructions using sparse parameterizations of the unknown conductivity on optimal grids that are computed as part of the inversion. We follow the approach in Borcea et al (2008 Inverse Problems 24 035013) and Vasquez (2006 PhD thesis Rice University, Houston, TX, USA) that connects inverse discrete problems for resistor networks to continuum EIT problems, using optimal grids. The algorithm in Borcea et al (2008 Inverse Problems 24 035013) and Vasquez (2006 PhD Thesis Rice University, Houston, TX, USA) is based on circular resistor networks, and solves the EIT problem with full boundary measurements. It is extended in Borcea et al (2010 Inverse Problems 26 045010) to EIT with partial boundary measurements, using extremal quasi-conformal mappings that transform the problem to one with full boundary measurements. Here we introduce a different class of optimal grids, based on resistor networks with pyramidal topology, that is better suited for the partial measurements setup. We prove the unique solvability of the discrete inverse problem for these networks and develop an algorithm for finding them from the measurements of the Dirichlet to Neumann map. Then, we show how to use the networks to define the optimal grids and to approximate the unknown conductivity. We assess the performance of our approach with numerical simulations and compare the results with those in Borcea et al (2010)

  19. Measuring distance through dense weighted networks: The case of hospital-associated pathogens.

    Directory of Open Access Journals (Sweden)

    Tjibbe Donker

    2017-08-01

    Full Text Available Hospital networks, formed by patients visiting multiple hospitals, affect the spread of hospital-associated infections, resulting in differences in risks for hospitals depending on their network position. These networks are increasingly used to inform strategies to prevent and control the spread of hospital-associated pathogens. However, many studies only consider patients that are received directly from the initial hospital, without considering the effect of indirect trajectories through the network. We determine the optimal way to measure the distance between hospitals within the network, by reconstructing the English hospital network based on shared patients in 2014-2015, and simulating the spread of a hospital-associated pathogen between hospitals, taking into consideration that each intermediate hospital conveys a delay in the further spread of the pathogen. While the risk of transferring a hospital-associated pathogen between directly neighbouring hospitals is a direct reflection of the number of shared patients, the distance between two hospitals far-away in the network is determined largely by the number of intermediate hospitals in the network. Because the network is dense, most long distance transmission chains in fact involve only few intermediate steps, spreading along the many weak links. The dense connectivity of hospital networks, together with a strong regional structure, causes hospital-associated pathogens to spread from the initial outbreak in a two-step process: first, the directly surrounding hospitals are affected through the strong connections, second all other hospitals receive introductions through the multitude of weaker links. Although the strong connections matter for local spread, weak links in the network can offer ideal routes for hospital-associated pathogens to travel further faster. This hold important implications for infection prevention and control efforts: if a local outbreak is not controlled in time

  20. A Neural Network Approach to Fluid Quantity Measurement in Dynamic Environments

    CERN Document Server

    Terzic, Edin; Nagarajah, Romesh; Alamgir, Muhammad

    2012-01-01

    Sloshing causes liquid to fluctuate, making accurate level readings difficult to obtain in dynamic environments. The measurement system described uses a single-tube capacitive sensor to obtain an instantaneous level reading of the fluid surface, thereby accurately determining the fluid quantity in the presence of slosh. A neural network based classification technique has been applied to predict the actual quantity of the fluid contained in a tank under sloshing conditions.   In A neural network approach to fluid quantity measurement in dynamic environments, effects of temperature variations and contamination on the capacitive sensor are discussed, and the authors propose that these effects can also be eliminated with the proposed neural network based classification system. To examine the performance of the classification system, many field trials were carried out on a running vehicle at various tank volume levels that range from 5 L to 50 L. The effectiveness of signal enhancement on the neural network base...

  1. Vertex centrality as a measure of information flow in Italian Corporate Board Networks

    Science.gov (United States)

    Grassi, Rosanna

    2010-06-01

    The aim of this article is to investigate the governance models of companies listed on the Italian Stock Exchange by using a network approach, which describes the interlinks between boards of directors. Following mainstream literature, I construct a weighted graph representing the listed companies (vertices) and their relationships (weighted edges), the Corporate Board Network; I then apply three different vertex centrality measures: degree, betweenness and flow betweenness. What emerges from the network construction and by applying the degree centrality is a structure with a large number of connections but not particularly dense, where the presence of a small number of highly connected nodes (hubs) is evident. Then I focus on betweenness and flow betweenness; indeed I expect that these centrality measures may give a representation of the intensity of the relationship between companies, capturing the volume of information flowing from one vertex to another. Finally, I investigate the possible scale-free structure of the network.

  2. Measuring dynamic process of working memory training with functional brain networks

    Directory of Open Access Journals (Sweden)

    Hong Wang

    2015-12-01

    Full Text Available In this paper, we proposed the functional brain networks and graphic theory method to measure the effect of working memory training on the neural activities. 12 subjects were recruited in this study, and they did the same working memory task before they had been trained and after training. We architected functional brain networks based on EEG coherence and calculated properties of brain networks to measure the neural co-activities and the working memory level of subjects. As the result, the internal connections in frontal region decreased after working memory training, but the connection between frontal region and top region increased. And the more small-world feature was observed after training. The features observed above were in alpha (8-13 Hz and beta (13-30 Hz bands. The functional brain networks based on EEG coherence proposed in this paper can be used as the indicator of working memory level.

  3. Fibre optical measuring network based on quasi-distributed amplitude sensors for detecting deformation loads

    International Nuclear Information System (INIS)

    Kul'chin, Yurii N; Kolchinskiy, V A; Kamenev, O T; Petrov, Yu S

    2013-01-01

    A new design of a sensitive element for a fibre optical sensor of deformation loads is proposed. A distributed fibre optical measuring network, aimed at determining both the load application point and the load mass, has been developed based on these elements. It is shown that neural network methods of data processing make it possible to combine quasi-distributed amplitude sensors of different types into a unified network. The results of the experimental study of a breadboard of a fibre optical measuring network are reported, which demonstrate successful reconstruction of the trajectory of a moving object (load) with a spatial resolution of 8 cm, as well as the load mass in the range of 1 – 10 kg with a sensitivity of 0.043 kg -1 . (laser optics 2012)

  4. Measuring the collateral network pressure to minimize paraplegia risk in thoracoabdominal aneurysm resection.

    Science.gov (United States)

    Etz, Christian D; Zoli, Stefano; Bischoff, Moritz S; Bodian, Carol; Di Luozzo, Gabriele; Griepp, Randall B

    2010-12-01

    To minimize paraplegia during thoracoabdominal aortic aneurysm repair, the concept of the collateral network was developed. That is, spinal cord perfusion is provided by an interconnecting complex of vessels in the intraspinal, paraspinous, and epidural space and in the paravertebral muscles, including intercostal and lumbar segmental as well as subclavian and hypogastric arteries. Collateral network pressure was measured with a catheter in the distal end of a ligated segmental artery in pigs and human beings. In the pig, collateral network pressure was 75% of the simultaneous mean aortic pressure. With complete segmental arterial ligation, it fell to 27% of baseline, recovering to 40% at 24 hours and 90% at 120 hours. Spinal cord injury occurred in approximately 50% of animals. When all segmental arteries were taken in 2 stages a week apart, collateral network pressure fell only to 50% to 70% of baseline, and spinal cord injury was rare. In human beings, baseline collateral network pressure also was 75% of mean aortic pressure, fell in proportion to the number of segmental arteries ligated, and began recovery within 24 hours. Collateral network pressure was lower with nonpulsatile distal bypass than with pulsatile perfusion. After subtraction of a measure of spinal cord outflow pressure (cerebrospinal fluid pressure or central venous pressure), collateral network pressure provides a clinically useful estimate of spinal cord perfusion pressure. Copyright © 2010. Published by Mosby, Inc.

  5. Directed clustering coefficient as a measure of systemic risk in complex banking networks

    Science.gov (United States)

    Tabak, Benjamin M.; Takami, Marcelo; Rocha, Jadson M. C.; Cajueiro, Daniel O.; Souza, Sergio R. S.

    2014-01-01

    Recent literature has focused on the study of systemic risk in complex networks. It is clear now, after the crisis of 2008, that the aggregate behavior of the interaction among agents is not straightforward and it is very difficult to predict. Contributing to this debate, this paper shows that the directed clustering coefficient may be used as a measure of systemic risk in complex networks. Furthermore, using data from the Brazilian interbank network, we show that the directed clustering coefficient is negatively correlated with domestic interest rates.

  6. The Jackson Queueing Network Model Built Using Poisson Measures. Application To A Bank Model

    Directory of Open Access Journals (Sweden)

    Ciuiu Daniel

    2014-07-01

    Full Text Available In this paper we will build a bank model using Poisson measures and Jackson queueing networks. We take into account the relationship between the Poisson and the exponential distributions, and we consider for each credit/deposit type a node where shocks are modeled as the compound Poisson processes. The transmissions of the shocks are modeled as moving between nodes in Jackson queueing networks, the external shocks are modeled as external arrivals, and the absorption of shocks as departures from the network.

  7. Least-squares methods for identifying biochemical regulatory networks from noisy measurements

    Directory of Open Access Journals (Sweden)

    Heslop-Harrison Pat

    2007-01-01

    Full Text Available Abstract Background We consider the problem of identifying the dynamic interactions in biochemical networks from noisy experimental data. Typically, approaches for solving this problem make use of an estimation algorithm such as the well-known linear Least-Squares (LS estimation technique. We demonstrate that when time-series measurements are corrupted by white noise and/or drift noise, more accurate and reliable identification of network interactions can be achieved by employing an estimation algorithm known as Constrained Total Least Squares (CTLS. The Total Least Squares (TLS technique is a generalised least squares method to solve an overdetermined set of equations whose coefficients are noisy. The CTLS is a natural extension of TLS to the case where the noise components of the coefficients are correlated, as is usually the case with time-series measurements of concentrations and expression profiles in gene networks. Results The superior performance of the CTLS method in identifying network interactions is demonstrated on three examples: a genetic network containing four genes, a network describing p53 activity and mdm2 messenger RNA interactions, and a recently proposed kinetic model for interleukin (IL-6 and (IL-12b messenger RNA expression as a function of ATF3 and NF-κB promoter binding. For the first example, the CTLS significantly reduces the errors in the estimation of the Jacobian for the gene network. For the second, the CTLS reduces the errors from the measurements that are corrupted by white noise and the effect of neglected kinetics. For the third, it allows the correct identification, from noisy data, of the negative regulation of (IL-6 and (IL-12b by ATF3. Conclusion The significant improvements in performance demonstrated by the CTLS method under the wide range of conditions tested here, including different levels and types of measurement noise and different numbers of data points, suggests that its application will enable

  8. A measure of the denseness of a phylogenetic network. [by sequenced proteins from extant species

    Science.gov (United States)

    Holmquist, R.

    1978-01-01

    An objective measure of phylogenetic denseness is developed to examine various phylogenetic criteria: alpha- and beta-hemoglobin, myoglobin, cytochrome c, and the parvalbumin family. Attention is given to the number of nucleotide replacements separating homologous sequences, and to the topology of the network (in other words, to the qualitative nature of the network as defined by how closely the studied species are related). Applications include quantitative comparisons of species origin, relation, and rates of evolution.

  9. Automatic Leak Detection in Buried Plastic Pipes of Water Supply Networks by Means of Vibration Measurements

    OpenAIRE

    Martini, Alberto; Troncossi, Marco; Rivola, Alessandro

    2015-01-01

    The implementation of strategies for controlling water leaks is essential in order to reduce losses affecting distribution networks of drinking water. This paper focuses on leak detection by using vibration monitoring techniques. The long-term goal is the development of a system for automatic early detection of burst leaks in service pipes. An experimental campaign was started to measure vibrations transmitted along water pipes by real burst leaks occurring in actual water supply networks. Th...

  10. A quantitative approach to measure road network information based on edge diversity

    Science.gov (United States)

    Wu, Xun; Zhang, Hong; Lan, Tian; Cao, Weiwei; He, Jing

    2015-12-01

    The measure of map information has been one of the key issues in assessing cartographic quality and map generalization algorithms. It is also important for developing efficient approaches to transfer geospatial information. Road network is the most common linear object in real world. Approximately describe road network information will benefit road map generalization, navigation map production and urban planning. Most of current approaches focused on node diversities and supposed that all the edges are the same, which is inconsistent to real-life condition, and thus show limitations in measuring network information. As real-life traffic flow are directed and of different quantities, the original undirected vector road map was first converted to a directed topographic connectivity map. Then in consideration of preferential attachment in complex network study and rich-club phenomenon in social network, the from and to weights of each edge are assigned. The from weight of a given edge is defined as the connectivity of its end node to the sum of the connectivities of all the neighbors of the from nodes of the edge. After getting the from and to weights of each edge, edge information, node information and the whole network structure information entropies could be obtained based on information theory. The approach has been applied to several 1 square mile road network samples. Results show that information entropies based on edge diversities could successfully describe the structural differences of road networks. This approach is a complementarity to current map information measurements, and can be extended to measure other kinds of geographical objects.

  11. Data Collection Manual for Academic and Research Library Network Statistics and Performance Measures.

    Science.gov (United States)

    Shim, Wonsik "Jeff"; McClure, Charles R.; Fraser, Bruce T.; Bertot, John Carlo

    This manual provides a beginning approach for research libraries to better describe the use and users of their networked services. The manual also aims to increase the visibility and importance of developing such statistics and measures. Specific objectives are: to identify selected key statistics and measures that can describe use and users of…

  12. Using network centrality measures to improve national journal classification lists

    Energy Technology Data Exchange (ETDEWEB)

    Zuccala, A.; Robinson-Garcia, N.; Repiso, R.; Torres-Salinas, D

    2016-07-01

    Research productivity for the scholar is often evaluated on the basis of his/her journal articles; however, specific journals are said to possess a higher measure of impact than others(Archambault & Larivière, 2009; Garfield, 2006; Glänzel & Moed, 2002). When a scholar decides where to publish, (s)he might consider a journal’s impact factor. Although Garfield (1973) claimed that citation counts to individual articles will determine the impact factor of a journal, newer evidence points to the contrary: a journal with a high impact factor can also influence an article’s readership and subsequent citation rates (Larivière & Gingras, 2010). This “chicken-and-egg” dispute (i.e., citations first or impact first?) can be tested, but can still have negative consequences for how journals are selected, rated, listed, and used by policymakers for developing measures of scholarly performance. For instance, in countries like Denmark and Spain classified journal lists are now being produced and used in the calculation of nationwide performance indicators. As a result, Danish and Spanish scholars are advised to contribute to journals of high “authority” (as in the former) or those within a high class (as in the latter). This can create a few problems. (Author)

  13. Measuring the effectiveness of protected area networks in reducing deforestation.

    Science.gov (United States)

    Andam, Kwaw S; Ferraro, Paul J; Pfaff, Alexander; Sanchez-Azofeifa, G Arturo; Robalino, Juan A

    2008-10-21

    Global efforts to reduce tropical deforestation rely heavily on the establishment of protected areas. Measuring the effectiveness of these areas is difficult because the amount of deforestation that would have occurred in the absence of legal protection cannot be directly observed. Conventional methods of evaluating the effectiveness of protected areas can be biased because protection is not randomly assigned and because protection can induce deforestation spillovers (displacement) to neighboring forests. We demonstrate that estimates of effectiveness can be substantially improved by controlling for biases along dimensions that are observable, measuring spatial spillovers, and testing the sensitivity of estimates to potential hidden biases. We apply matching methods to evaluate the impact on deforestation of Costa Rica's renowned protected-area system between 1960 and 1997. We find that protection reduced deforestation: approximately 10% of the protected forests would have been deforested had they not been protected. Conventional approaches to evaluating conservation impact, which fail to control for observable covariates correlated with both protection and deforestation, substantially overestimate avoided deforestation (by over 65%, based on our estimates). We also find that deforestation spillovers from protected to unprotected forests are negligible. Our conclusions are robust to potential hidden bias, as well as to changes in modeling assumptions. Our results show that, with appropriate empirical methods, conservation scientists and policy makers can better understand the relationships between human and natural systems and can use this to guide their attempts to protect critical ecosystem services.

  14. Reverse-engineering of gene networks for regulating early blood development from single-cell measurements.

    Science.gov (United States)

    Wei, Jiangyong; Hu, Xiaohua; Zou, Xiufen; Tian, Tianhai

    2017-12-28

    Recent advances in omics technologies have raised great opportunities to study large-scale regulatory networks inside the cell. In addition, single-cell experiments have measured the gene and protein activities in a large number of cells under the same experimental conditions. However, a significant challenge in computational biology and bioinformatics is how to derive quantitative information from the single-cell observations and how to develop sophisticated mathematical models to describe the dynamic properties of regulatory networks using the derived quantitative information. This work designs an integrated approach to reverse-engineer gene networks for regulating early blood development based on singel-cell experimental observations. The wanderlust algorithm is initially used to develop the pseudo-trajectory for the activities of a number of genes. Since the gene expression data in the developed pseudo-trajectory show large fluctuations, we then use Gaussian process regression methods to smooth the gene express data in order to obtain pseudo-trajectories with much less fluctuations. The proposed integrated framework consists of both bioinformatics algorithms to reconstruct the regulatory network and mathematical models using differential equations to describe the dynamics of gene expression. The developed approach is applied to study the network regulating early blood cell development. A graphic model is constructed for a regulatory network with forty genes and a dynamic model using differential equations is developed for a network of nine genes. Numerical results suggests that the proposed model is able to match experimental data very well. We also examine the networks with more regulatory relations and numerical results show that more regulations may exist. We test the possibility of auto-regulation but numerical simulations do not support the positive auto-regulation. In addition, robustness is used as an importantly additional criterion to select candidate

  15. Bridging centrality: A new indicator to measure the positioning of actors in R&D networks

    Energy Technology Data Exchange (ETDEWEB)

    Scherngell, T.; Wanzenboeck, I.; Berge, L.

    2016-07-01

    In the recent past, we can observe growing interest in the STI community in the notion of positioning indicators, shifting emphasis to actors in the innovation process and their R&D inter-linkages with other actors. In relation to this, we suggest a new approach for assessing the positioning of actors relying on the notion of bridging centrality (BC). Based on the concept of bridging paths, i.e. a set of two links connecting three actors across three different aggregate nodes (e.g. organisations, regions or countries), we argue that triangulation in networks is a key issue for knowledge recombinations and the extension of an actor's knowledge base. As bridges are most often not empirically observable at the individual level of research teams, we propose an approximated BC measure that provides a flexible framework for dealing with the aggregation problem in positioning actors. Hereby, BC is viewed as a function of an aggregate node's (i) participation intensity in the network, (ii) its openness to other nodes (i.e. the relative outward orientation of network links), and iii) the diversification of links to other nodes. In doing so, we provide an integrative perspective that enables us to achieve a better understanding of the positioning of certain actors in R&D networks. An illustrative example on the co-patent network of European regions demonstrates the performance and usefulness of our BC measure for networks constructed at the aggregated level, i.e. regions in our example. A region's outward orientation and the diversification of its network links moderates the influence of regional scale on network centrality. This is a major strength of the measure, and it paves the way for future studies to examine the role of certain aggregate node's, and, by this, contributes to the debate on positioning indicators in the STI context. (Author)

  16. A new centrality measure for identifying influential nodes in social networks

    Science.gov (United States)

    Rhouma, Delel; Ben Romdhane, Lotfi

    2018-04-01

    The identification of central nodes has been a key problem in the field of social network analysis. In fact, it is a measure that accounts the popularity or the visibility of an actor within a network. In order to capture this concept, various measures, either sample or more elaborate, has been developed. Nevertheless, many of "traditional" measures are not designed to be applicable to huge data. This paper sets out a new node centrality index suitable for large social network. It uses the amount of the neighbors of a node and connections between them to characterize a "pivot" node in the graph. We presented experimental results on real data sets which show the efficiency of our proposal.

  17. Technical Note: Novel method for water vapour monitoring using wireless communication networks measurements

    Science.gov (United States)

    David, N.; Alpert, P.; Messer, H.

    2009-04-01

    We propose a new technique that overcomes the obstacles of the existing methods for monitoring near-surface water vapour, by estimating humidity from data collected through existing wireless communication networks. Weather conditions and atmospheric phenomena affect the electromagnetic channel, causing attenuations to the radio signals. Thus, wireless communication networks are in effect built-in environmental monitoring facilities. The wireless microwave links, used in these networks, are widely deployed by cellular providers for backhaul communication between base stations, a few tens of meters above ground level. As a result, if all available measurements are used, the proposed method can provide moisture observations with high spatial resolution and potentially high temporal resolution. Further, the implementation cost is minimal, since the data used are already collected and saved by the cellular operators. In addition - many of these links are installed in areas where access is difficult such as orographic terrain and complex topography. As such, our method enables measurements in places that have been hard to measure in the past, or have never been measured before. The technique is restricted to weather conditions which exclude rain, fog or clouds along the propagation path. Strong winds that may cause movement of the link transmitter or receiver (or both) may also interfere with the ability to conduct accurate measurements. We present results from real-data measurements taken from two microwave links used in a backhaul cellular network that show convincing correlation to surface station humidity measurements. The measurements were taken daily in two sites, one in northern Israel (28 measurements), the other in central Israel (29 measurements). The correlation between the microwave link measurements and the humidity gauges were 0.9 and 0.82 for the north and central sites, respectively. The Root Mean Square Differences (RMSD) were 1.8 g/m3 and 3.4 g/m3 for

  18. 3D Facial Similarity Measure Based on Geodesic Network and Curvatures

    Directory of Open Access Journals (Sweden)

    Junli Zhao

    2014-01-01

    Full Text Available Automated 3D facial similarity measure is a challenging and valuable research topic in anthropology and computer graphics. It is widely used in various fields, such as criminal investigation, kinship confirmation, and face recognition. This paper proposes a 3D facial similarity measure method based on a combination of geodesic and curvature features. Firstly, a geodesic network is generated for each face with geodesics and iso-geodesics determined and these network points are adopted as the correspondence across face models. Then, four metrics associated with curvatures, that is, the mean curvature, Gaussian curvature, shape index, and curvedness, are computed for each network point by using a weighted average of its neighborhood points. Finally, correlation coefficients according to these metrics are computed, respectively, as the similarity measures between two 3D face models. Experiments of different persons’ 3D facial models and different 3D facial models of the same person are implemented and compared with a subjective face similarity study. The results show that the geodesic network plays an important role in 3D facial similarity measure. The similarity measure defined by shape index is consistent with human’s subjective evaluation basically, and it can measure the 3D face similarity more objectively than the other indices.

  19. Development and validation of a survey to measure features of clinical networks.

    Science.gov (United States)

    Brown, Bernadette Bea; Haines, Mary; Middleton, Sandy; Paul, Christine; D'Este, Catherine; Klineberg, Emily; Elliott, Elizabeth

    2016-09-30

    Networks of clinical experts are increasingly being implemented as a strategy to improve health care processes and outcomes and achieve change in the health system. Few are ever formally evaluated and, when this is done, not all networks are equally successful in their efforts. There is a need to formatively assess the strategic and operational management and leadership of networks to identify where functioning could be improved to maximise impact. This paper outlines the development and psychometric evaluation of an Internet survey to measure features of clinical networks and provides descriptive results from a sample of members of 19 diverse clinical networks responsible for evidence-based quality improvement across a large geographical region. Instrument development was based on: a review of published and grey literature; a qualitative study of clinical network members; a program logic framework; and consultation with stakeholders. The resulting domain structure was validated for a sample of 592 clinical network members using confirmatory factor analysis. Scale reliability was assessed using Cronbach's alpha. A summary score was calculated for each domain and aggregate level means and ranges are reported. The instrument was shown to have good construct validity across seven domains as demonstrated by a high level of internal consistency, and all Cronbach's α coefficients were equal to or above 0.75. In the survey sample of network members there was strong reported commitment and belief in network-led quality improvement initiatives, which were perceived to have improved quality of care (72.8 %) and patient outcomes (63.2 %). Network managers were perceived to be effective leaders and clinical co-chairs were perceived as champions for change. Perceived external support had the lowest summary score across the seven domains. This survey, which has good construct validity and internal reliability, provides a valid instrument to use in future research related to

  20. Nanotechnology knowledge diffusion: measuring the impact of the research networking and a strategy for improvement

    Science.gov (United States)

    Liu, Xuan; Jiang, Shan; Chen, Hsinchun; Larson, Catherine A.; Roco, Mihail C.

    2014-09-01

    Given the global increase in public funding for nanotechnology research and development, it is even more important to support projects with promising return on investment. A main return is the benefit to other researchers and to the entire field through knowledge diffusion, invention, and innovation. The social network of researchers is one of the channels through which this happens. This study considers the scientific publication network in the field of nanotechnology, and evaluates how knowledge diffusion through coauthorship and citations is affected in large institutions by the location and connectivity of individual researchers in the network. The relative position and connectivity of a researcher is measured by various social network metrics, including degree centrality, Bonacich Power centrality, structural holes, and betweenness centrality. Leveraging the Cox regression model, we analyzed the temporal relationships between knowledge diffusion and social network measures of researchers in five leading universities in the United States using papers published from 2000 to 2010. The results showed that the most significant effects on knowledge diffusion in the field of nanotechnology were from the structural holes of the network and the degree centrality of individual researchers. The data suggest that a researcher has potential to perform better in knowledge creation and diffusion on boundary-spanning positions between different communities and when he or she has a high level of connectivity in the knowledge network. These observations may lead to improved strategies in planning, conducting, and evaluating multidisciplinary nanotechnology research. The paper also identifies the researchers who made most significant contributions to nanotechnology knowledge diffusion in the networks of five leading U.S. universities.

  1. Accessibility in networks: A useful measure for understanding social insect nest architecture

    International Nuclear Information System (INIS)

    Viana, Matheus P.; Fourcassié, Vincent; Perna, Andrea; Costa, Luciano da F.; Jost, Christian

    2013-01-01

    Networks and the associated tools from graph theory have now become well-established approaches to study natural as well as human-made systems. While early studies focused on topology and connectivity, the recent literature has acknowledged the importance of the dynamical properties of these networks. Here we focus on such a dynamic measure: accessibility. It characterizes for any given movement dynamics (such as random walks) the average number of nodes that can be reached in exactly h steps (out-accessibility), or the average number of nodes from which a given node can be reached (in-accessibility). This focus on dynamics makes accessibility particularly appropriate to study movement on networks and to detect complementary properties with respect to topology-based measurements such as betweenness centrality. We apply this measure to six nests of Cubitermes termites. Their mushroom-like 3D architectures consist of chambers and connecting tunnels that can be associated to nodes and edges in a communication network. Accessibilities turn out to be particularly low in the bottom part of the nests that link them to their underground tunneling network. We interpret this result in the context of anti-predator (ants) behavior and/or as a side effect of the global nest shape.

  2. Solar radiation measurements at the network of six sites in the UK, January - December 2001

    Energy Technology Data Exchange (ETDEWEB)

    Driscoll, C.M.H.; Campbell, J.I.; Pearson, A.J.; Grainger, K.J.L.; Dean, S.F.; Clark, I.E

    2002-04-01

    A summary of the results from January to December 2001 of a survey of solar radiation levels at the UK network of six solar radiation measurement sites is presented. The network consists of three NRPB sites at Chilton, Leeds and (monitoring since 1988) and three Meteorological Office stations at Camborne, Kinloss and Lerwick (monitoring since 1993). Visible (400-770 nm), ultraviolet UVA radiation (320-400 nm) and erythemally weighted ultraviolet radiation UVR{sub eff} (280-400 nm) have been measured simultaneously using a three detector measurement system. Results are compared with calculated irradiances of ultraviolet radiation and published illuminance data, and with data for the measurement period from 1988 to 2000. Yearly reports have been produced for selected sites, giving the daily solar index (which is a measure of the sunburn potential for sensitive skin types) throughout the year. (author)

  3. Solar radiation measurements at the network of six sites in the UK, January - December 2001

    International Nuclear Information System (INIS)

    Driscoll, C.M.H.; Campbell, J.I.; Pearson, A.J.; Grainger, K.J.L.; Dean, S.F.; Clark, I.E.

    2002-01-01

    A summary of the results from January to December 2001 of a survey of solar radiation levels at the UK network of six solar radiation measurement sites is presented. The network consists of three NRPB sites at Chilton, Leeds and (monitoring since 1988) and three Meteorological Office stations at Camborne, Kinloss and Lerwick (monitoring since 1993). Visible (400-770 nm), ultraviolet UVA radiation (320-400 nm) and erythemally weighted ultraviolet radiation UVR eff (280-400 nm) have been measured simultaneously using a three detector measurement system. Results are compared with calculated irradiances of ultraviolet radiation and published illuminance data, and with data for the measurement period from 1988 to 2000. Yearly reports have been produced for selected sites, giving the daily solar index (which is a measure of the sunburn potential for sensitive skin types) throughout the year. (author)

  4. Network neighborhood analysis with the multi-node topological overlap measure.

    Science.gov (United States)

    Li, Ai; Horvath, Steve

    2007-01-15

    The goal of neighborhood analysis is to find a set of genes (the neighborhood) that is similar to an initial 'seed' set of genes. Neighborhood analysis methods for network data are important in systems biology. If individual network connections are susceptible to noise, it can be advantageous to define neighborhoods on the basis of a robust interconnectedness measure, e.g. the topological overlap measure. Since the use of multiple nodes in the seed set may lead to more informative neighborhoods, it can be advantageous to define multi-node similarity measures. The pairwise topological overlap measure is generalized to multiple network nodes and subsequently used in a recursive neighborhood construction method. A local permutation scheme is used to determine the neighborhood size. Using four network applications and a simulated example, we provide empirical evidence that the resulting neighborhoods are biologically meaningful, e.g. we use neighborhood analysis to identify brain cancer related genes. An executable Windows program and tutorial for multi-node topological overlap measure (MTOM) based analysis can be downloaded from the webpage (http://www.genetics.ucla.edu/labs/horvath/MTOM/).

  5. Study on the three-station typical network deployments of workspace Measurement and Positioning System

    Science.gov (United States)

    Xiong, Zhi; Zhu, J. G.; Xue, B.; Ye, Sh. H.; Xiong, Y.

    2013-10-01

    As a novel network coordinate measurement system based on multi-directional positioning, workspace Measurement and Positioning System (wMPS) has outstanding advantages of good parallelism, wide measurement range and high measurement accuracy, which makes it to be the research hotspots and important development direction in the field of large-scale measurement. Since station deployment has a significant impact on the measurement range and accuracy, and also restricts the use-cost, the optimization method of station deployment was researched in this paper. Firstly, positioning error model was established. Then focusing on the small network consisted of three stations, the typical deployments and error distribution characteristics were studied. Finally, through measuring the simulated fuselage using typical deployments at the industrial spot and comparing the results with Laser Tracker, some conclusions are obtained. The comparison results show that under existing prototype conditions, I_3 typical deployment of which three stations are distributed in a straight line has an average error of 0.30 mm and the maximum error is 0.50 mm in the range of 12 m. Meanwhile, C_3 typical deployment of which three stations are uniformly distributed in the half-circumference of an circle has an average error of 0.17 mm and the maximum error is 0.28 mm. Obviously, C_3 typical deployment has a higher control effect on precision than I_3 type. The research work provides effective theoretical support for global measurement network optimization in the future work.

  6. A Neural Network Approach to Fluid Level Measurement in Dynamic Environments Using a Single Capacitive Sensor

    Directory of Open Access Journals (Sweden)

    Edin TERZIC

    2010-03-01

    Full Text Available A measurement system has been developed using a single tube capacitive sensor to accurately determine the fluid level in vehicular fuel tanks. A novel approach based on artificial neural networks based signal pre-processing and classification has been described in this article. A broad investigation on the Backpropagation neural network and some selected signal pre-processing filters, namely, Moving Mean, Moving Median, and Wavelet Filter has also been presented. An on field drive trial was conducted under normal driving conditions at various fuel volumes ranging from 5 L to 50 L to acquire training samples from the capacitive sensor. A second field trial was conducted to obtain test samples to verify the performance of the neural network. The neural network was trained and verified with 50 % of the training and test samples. The results obtained using the neural network approach having different filtration methods are compared with the results obtained using simple Moving Mean and Moving Median functions. It is demonstrated that the Backpropagation neural network with Moving Median filter produced the most accurate outcome compared with the other signal filtration methods.

  7. Continuous-variable Measurement-device-independent Quantum Relay Network with Phase-sensitive Amplifiers

    Science.gov (United States)

    Li, Fei; Zhao, Wei; Guo, Ying

    2018-01-01

    Continuous-variable (CV) measurement-device-independent (MDI) quantum cryptography is now heading towards solving the practical problem of implementing scalable quantum networks. In this paper, we show that a solution can come from deploying an optical amplifier in the CV-MDI system, aiming to establish a high-rate quantum network. We suggest an improved CV-MDI protocol using the EPR states coupled with optical amplifiers. It can implement a practical quantum network scheme, where the legal participants create the secret correlations by using EPR states connecting to an untrusted relay via insecure links and applying the multi-entangled Greenberger-Horne-Zeilinger (GHZ) state analysis at relay station. Despite the possibility that the relay could be completely tampered with and imperfect links are subject to the powerful attacks, the legal participants are still able to extract a secret key from network communication. The numerical simulation indicates that the quantum network communication can be achieved in an asymmetric scenario, fulfilling the demands of a practical quantum network. Furthermore, we show that the use of optical amplifiers can compensate the inherent imperfections and improve the secret key rate of the CV-MDI system.

  8. Comparing Social Network Analysis of Posts with Counting of Posts as a Measurement of Learners' Participation in Facebook Discussions

    Science.gov (United States)

    Lee, Hye Yeon; Lee, Hyeon Woo

    2016-01-01

    With the currently growing interest in social network services, many college courses use social network services as platforms for discussions, and a number of studies have been conducted on the use of social network analysis to measure students' participation in online discussions. This study aims to demonstrate the difference between counting…

  9. Collaboration in Action: Measuring and Improving Contracting Performance in the University of California Contracting Network

    Science.gov (United States)

    Tran, Tam; Bowman-Carpio, LeeAnna; Buscher, Nate; Davidson, Pamela; Ford, Jennifer J.; Jenkins, Erick; Kalay, Hillary Noll; Nakazono, Terry; Orescan, Helene; Sak, Rachael; Shin, Irene

    2017-01-01

    In 2013, the University of California, Biomedical Research, Acceleration, Integration, and Development (UC BRAID) convened a regional network of contracting directors from the five University of California (UC) health campuses to: (i) increase collaboration, (ii) operationalize and measure common metrics as a basis for performance improvement…

  10. Measuring urban rainfall using microwave links from commercial cellular communication networks

    NARCIS (Netherlands)

    Overeem, A.; Leijnse, H.; Uijlenhoet, R.

    2011-01-01

    The estimation of rainfall using commercial microwave links is a new and promising measurement technique. Commercial link networks cover large parts of the land surface of the earth and have a high density, particularly in urban areas. Rainfall attenuates the electromagnetic signals transmitted

  11. Measuring Creative Potential: Using Social Network Analysis to Monitor a Learners' Creative Capacity

    Science.gov (United States)

    Dawson, Shane; Tan, Jennifer Pei Ling; McWilliam, Erica

    2011-01-01

    Despite the burgeoning rhetoric from political, social and educational commentators regarding creativity and learning and teaching, there is a paucity of scalable and measurable examples of creativity-centric pedagogical practice. This paper makes an argument for the application of social network visualisations to inform and support…

  12. Mechanical properties of the collagen network in human articular cartilage as measured by osmotic stress technique

    NARCIS (Netherlands)

    Basser, P.J.; Schneiderman, R.; Bank, R.A.; Wachtel, E.; Maroudas, A.

    1998-01-01

    We have used an isotropic osmotic stress technique to assess the swelling pressures of human articular cartilage over a wide range of hydrations in order to determine from these measurements, for the first time, the tensile stress in the collagen network, P(c), as a function of hydration. Osmotic

  13. Tiny Integrated Network Analyzer for Noninvasive Measurements of Electrically Small Antennas

    DEFF Research Database (Denmark)

    Buskgaard, Emil Feldborg; Krøyer, Ben; Tatomirescu, Alexandru

    2016-01-01

    the system. The tiny integrated network analyzer is a stand-alone Arduino-based measurement system that utilizes the transmit signal of the system under test as its reference. It features a power meter with triggering ability, on-board memory, universal serial bus, and easy extendibility with general...

  14. A Measurement Study of the Structured Overlay Network in P2P File-Sharing Systems

    Directory of Open Access Journals (Sweden)

    Mo Zhou

    2007-01-01

    Full Text Available The architecture of P2P file-sharing applications has been developing to meet the needs of large scale demands. The structured overlay network, also known as DHT, has been used in these applications to improve the scalability, and robustness of the system, and to make it free from single-point failure. We believe that the measurement study of the overlay network used in the real file-sharing P2P systems can provide guidance for the designing of such systems, and improve the performance of the system. In this paper, we perform the measurement in two different aspects. First, a modified client is designed to provide view to the overlay network from a single-user vision. Second, the instances of crawler programs deployed in many nodes managed to crawl the user information of the overlay network as much as possible. We also find a vulnerability in the overlay network, combined with the character of the DNS service, a more serious DDoS attack can be launched.

  15. In situ recording of particle network formation in liquids by ion conductivity measurements.

    Science.gov (United States)

    Pfaffenhuber, Christian; Sörgel, Seniz; Weichert, Katja; Bele, Marjan; Mundinger, Tabea; Göbel, Marcus; Maier, Joachim

    2011-09-21

    The formation of fractal silica networks from a colloidal initial state was followed in situ by ion conductivity measurements. The underlying effect is a high interfacial lithium ion conductivity arising when silica particles are brought into contact with Li salt-containing liquid electrolytes. The experimental results were modeled using Monte Carlo simulations and tested using confocal fluorescence laser microscopy and ζ-potential measurements.

  16. Network analysis of surgical innovation: Measuring value and the virality of diffusion in robotic surgery.

    Directory of Open Access Journals (Sweden)

    George Garas

    Full Text Available Existing surgical innovation frameworks suffer from a unifying limitation, their qualitative nature. A rigorous approach to measuring surgical innovation is needed that extends beyond detecting simply publication, citation, and patent counts and instead uncovers an implementation-based value from the structure of the entire adoption cascades produced over time by diffusion processes. Based on the principles of evidence-based medicine and existing surgical regulatory frameworks, the surgical innovation funnel is described. This illustrates the different stages through which innovation in surgery typically progresses. The aim is to propose a novel and quantitative network-based framework that will permit modeling and visualizing innovation diffusion cascades in surgery and measuring virality and value of innovations.Network analysis of constructed citation networks of all articles concerned with robotic surgery (n = 13,240, Scopus® was performed (1974-2014. The virality of each cascade was measured as was innovation value (measured by the innovation index derived from the evidence-based stage occupied by the corresponding seed article in the surgical innovation funnel. The network-based surgical innovation metrics were also validated against real world big data (National Inpatient Sample-NIS®.Rankings of surgical innovation across specialties by cascade size and structural virality (structural depth and width were found to correlate closely with the ranking by innovation value (Spearman's rank correlation coefficient = 0.758 (p = 0.01, 0.782 (p = 0.008, 0.624 (p = 0.05, respectively which in turn matches the ranking based on real world big data from the NIS® (Spearman's coefficient = 0.673;p = 0.033.Network analysis offers unique new opportunities for understanding, modeling and measuring surgical innovation, and ultimately for assessing and comparing generative value between different specialties. The novel surgical innovation metrics

  17. Network analysis of surgical innovation: Measuring value and the virality of diffusion in robotic surgery.

    Science.gov (United States)

    Garas, George; Cingolani, Isabella; Panzarasa, Pietro; Darzi, Ara; Athanasiou, Thanos

    2017-01-01

    Existing surgical innovation frameworks suffer from a unifying limitation, their qualitative nature. A rigorous approach to measuring surgical innovation is needed that extends beyond detecting simply publication, citation, and patent counts and instead uncovers an implementation-based value from the structure of the entire adoption cascades produced over time by diffusion processes. Based on the principles of evidence-based medicine and existing surgical regulatory frameworks, the surgical innovation funnel is described. This illustrates the different stages through which innovation in surgery typically progresses. The aim is to propose a novel and quantitative network-based framework that will permit modeling and visualizing innovation diffusion cascades in surgery and measuring virality and value of innovations. Network analysis of constructed citation networks of all articles concerned with robotic surgery (n = 13,240, Scopus®) was performed (1974-2014). The virality of each cascade was measured as was innovation value (measured by the innovation index) derived from the evidence-based stage occupied by the corresponding seed article in the surgical innovation funnel. The network-based surgical innovation metrics were also validated against real world big data (National Inpatient Sample-NIS®). Rankings of surgical innovation across specialties by cascade size and structural virality (structural depth and width) were found to correlate closely with the ranking by innovation value (Spearman's rank correlation coefficient = 0.758 (p = 0.01), 0.782 (p = 0.008), 0.624 (p = 0.05), respectively) which in turn matches the ranking based on real world big data from the NIS® (Spearman's coefficient = 0.673;p = 0.033). Network analysis offers unique new opportunities for understanding, modeling and measuring surgical innovation, and ultimately for assessing and comparing generative value between different specialties. The novel surgical innovation metrics developed may

  18. A large scale analysis of information-theoretic network complexity measures using chemical structures.

    Directory of Open Access Journals (Sweden)

    Matthias Dehmer

    Full Text Available This paper aims to investigate information-theoretic network complexity measures which have already been intensely used in mathematical- and medicinal chemistry including drug design. Numerous such measures have been developed so far but many of them lack a meaningful interpretation, e.g., we want to examine which kind of structural information they detect. Therefore, our main contribution is to shed light on the relatedness between some selected information measures for graphs by performing a large scale analysis using chemical networks. Starting from several sets containing real and synthetic chemical structures represented by graphs, we study the relatedness between a classical (partition-based complexity measure called the topological information content of a graph and some others inferred by a different paradigm leading to partition-independent measures. Moreover, we evaluate the uniqueness of network complexity measures numerically. Generally, a high uniqueness is an important and desirable property when designing novel topological descriptors having the potential to be applied to large chemical databases.

  19. Greenhouse gas measurements from a UK network of tall towers: technical description and first results

    Science.gov (United States)

    Stanley, Kieran M.; Grant, Aoife; O'Doherty, Simon; Young, Dickon; Manning, Alistair J.; Stavert, Ann R.; Spain, T. Gerard; Salameh, Peter K.; Harth, Christina M.; Simmonds, Peter G.; Sturges, William T.; Oram, David E.; Derwent, Richard G.

    2018-03-01

    A network of three tall tower measurement stations was set up in 2012 across the United Kingdom to expand measurements made at the long-term background northern hemispheric site, Mace Head, Ireland. Reliable and precise in situ greenhouse gas (GHG) analysis systems were developed and deployed at three sites in the UK with automated instrumentation measuring a suite of GHGs. The UK Deriving Emissions linked to Climate Change (UK DECC) network uses tall (165-230 m) open-lattice telecommunications towers, which provide a convenient platform for boundary layer trace gas sampling. In this paper we describe the automated measurement system and first results from the UK DECC network for CO2, CH4, N2O, SF6, CO and H2. CO2 and CH4 are measured at all of the UK DECC sites by cavity ring-down spectroscopy (CRDS) with multiple inlet heights at two of the three tall tower sites to assess for boundary layer stratification. The short-term precisions (1σ on 1 min means) of CRDS measurements at background mole fractions for January 2012 to September 2015 is sampling temperatures. Automated alerts are generated and emailed to site operators when instrumental parameters are not within defined set ranges. Automated instrument shutdowns occur for critical errors such as carrier gas flow rate deviations. Results from the network give good spatial and temporal coverage of atmospheric mixing ratios within the UK since early 2012. Results also show that all measured GHGs are increasing in mole fraction over the selected reporting period and, except for SF6, exhibit a seasonal trend. CO2 and CH4 also show strong diurnal cycles, with night-time maxima and daytime minima in mole fractions.

  20. Novel method for water vapour monitoring using wireless communication networks measurements

    Science.gov (United States)

    David, N.; Alpert, P.; Messer, H.

    2010-09-01

    We propose a new technique for monitoring near-surface water vapour, by estimating humidity from data collected through existing wireless communication networks. Weather conditions and atmospheric phenomena affect the electromagnetic channel, causing attenuations to the radio signals. Thus, wireless communication networks are in effect built-in environmental monitoring facilities. The wireless microwave links, used in these networks, are widely deployed by cellular providers for backhaul communication between base stations, a few tens of meters above ground level. As a result, if all available measurements are used, the proposed method can provide moisture observations with high spatial resolution and potentially high temporal resolution. Further, the implementation cost is minimal, since the data used are already collected and saved by the cellular operators. In addition - many of these links are installed in areas where access is difficult such as orographic terrain and complex topography. As such, our method enables measurements in places that have been hard to measure in the past, or have never been measured before. The technique is restricted to weather conditions which exclude rain, fog or clouds along the propagation path. Strong winds that may cause movement of the link transmitter or receiver (or both) may also interfere with the ability to conduct accurate measurements. We present results from real-data measurements taken from microwave links used in a backhaul cellular network that show very good correlation with surface station humidity measurements (comparisons were performed for several links, found at different locations, during different time periods, showing correlations in the range of 0.5-0.9).

  1. An ANP-based network to measure the impact of Lean production on organisational performance

    Directory of Open Access Journals (Sweden)

    José Luis Ruano Pérez

    2018-04-01

    Full Text Available Purpose: The main objective of this research is to design a decision-making network, based on the Analytic Network Process (ANP technique (Saaty, 1996, which will include the main elements to take into account when stating the effect that the application of LP techniques has got on the performance of an organisation, measured this through a Performance Measurement System (PMS. Design/methodology/approach: The authors have carried out a scientific literature search to state what the main LP techniques are –and how to group them into different clusters- and have then applied the ANP, its first phase, in order to design the decisional network. Findings: There is a gap in the literature when trying to identify and quantify to what extent the implementation of LP techniques affects to organisational performance. The ANP is an appropriate technique to do so due to the need of gathering and quantifying experts’ opinions. Originality/value: The designed ANP-based network to measure the impact of LP over organisational performance is a novel approach. This paper justifies its usage and paves the way to implement the rest of the ANP phases in future research work.

  2. Employing the Gini coefficient to measure participation inequality in treatment-focused Digital Health Social Networks.

    Science.gov (United States)

    van Mierlo, Trevor; Hyatt, Douglas; Ching, Andrew T

    2016-01-01

    Digital Health Social Networks (DHSNs) are common; however, there are few metrics that can be used to identify participation inequality. The objective of this study was to investigate whether the Gini coefficient, an economic measure of statistical dispersion traditionally used to measure income inequality, could be employed to measure DHSN inequality. Quarterly Gini coefficients were derived from four long-standing DHSNs. The combined data set included 625,736 posts that were generated from 15,181 actors over 18,671 days. The range of actors (8-2323), posts (29-28,684), and Gini coefficients (0.15-0.37) varied. Pearson correlations indicated statistically significant associations between number of actors and number of posts (0.527-0.835, p  addiction networks (0.619 and 0.276, p  networks ( t  = -4.305 and -5.934, p  network engagement. Further, mixed-methods research investigating quantitative performance metrics is required.

  3. Growing complex network of citations of scientific papers: Modeling and measurements.

    Science.gov (United States)

    Golosovsky, Michael; Solomon, Sorin

    2017-01-01

    We consider the network of citations of scientific papers and use a combination of the theoretical and experimental tools to uncover microscopic details of this network growth. Namely, we develop a stochastic model of citation dynamics based on the copying-redirection-triadic closure mechanism. In a complementary and coherent way, the model accounts both for statistics of references of scientific papers and for their citation dynamics. Originating in empirical measurements, the model is cast in such a way that it can be verified quantitatively in every aspect. Such validation is performed by measuring citation dynamics of physics papers. The measurements revealed nonlinear citation dynamics, the nonlinearity being intricately related to network topology. The nonlinearity has far-reaching consequences including nonstationary citation distributions, diverging citation trajectories of similar papers, runaways or "immortal papers" with infinite citation lifetime, etc. Thus nonlinearity in complex network growth is our most important finding. In a more specific context, our results can be a basis for quantitative probabilistic prediction of citation dynamics of individual papers and of the journal impact factor.

  4. Effective comparative analysis of protein-protein interaction networks by measuring the steady-state network flow using a Markov model.

    Science.gov (United States)

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

    2016-10-06

    Comparative analysis of protein-protein interaction (PPI) networks provides an effective means of detecting conserved functional network modules across different species. Such modules typically consist of orthologous proteins with conserved interactions, which can be exploited to computationally predict the modules through network comparison. In this work, we propose a novel probabilistic framework for comparing PPI networks and effectively predicting the correspondence between proteins, represented as network nodes, that belong to conserved functional modules across the given PPI networks. The basic idea is to estimate the steady-state network flow between nodes that belong to different PPI networks based on a Markov random walk model. The random walker is designed to make random moves to adjacent nodes within a PPI network as well as cross-network moves between potential orthologous nodes with high sequence similarity. Based on this Markov random walk model, we estimate the steady-state network flow - or the long-term relative frequency of the transitions that the random walker makes - between nodes in different PPI networks, which can be used as a probabilistic score measuring their potential correspondence. Subsequently, the estimated scores can be used for detecting orthologous proteins in conserved functional modules through network alignment. Through evaluations based on multiple real PPI networks, we demonstrate that the proposed scheme leads to improved alignment results that are biologically more meaningful at reduced computational cost, outperforming the current state-of-the-art algorithms. The source code and datasets can be downloaded from http://www.ece.tamu.edu/~bjyoon/CUFID .

  5. Optical track width measurements below 100 nm using artificial neural networks

    Science.gov (United States)

    Smith, R. J.; See, C. W.; Somekh, M. G.; Yacoot, A.; Choi, E.

    2005-12-01

    This paper discusses the feasibility of using artificial neural networks (ANNs), together with a high precision scanning optical profiler, to measure very fine track widths that are considerably below the conventional diffraction limit of a conventional optical microscope. The ANN is trained using optical profiles obtained from tracks of known widths, the network is then assessed by applying it to test profiles. The optical profiler is an ultra-stable common path scanning interferometer, which provides extremely precise surface measurements. Preliminary results, obtained with a 0.3 NA objective lens and a laser wavelength of 633 nm, show that the system is capable of measuring a 50 nm track width, with a standard deviation less than 4 nm.

  6. Solar Radiation Measurement Using Raspberry Pi and Its Modelling Using Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Priya Selvanathan Shanmuga

    2016-01-01

    Full Text Available The advent of solar energy as the best alternative to traditional energy sources has led to an extensive study on the measurement and prediction of solar radiation. Devices such as pyranometer, pyrrheliometer, global UV radiometer are used for the measurement of solar radiation. The solar radiation measuring instruments available at Innovation Center, MIT Manipal were integrated with a Raspberry Pi to allow remote access to the data through the university Local Area Network. The connections of the data loggers and the Raspberry Pi were enclosed in a plastic box to prevent damage from the rainfall and humidity in Manipal. The solar radiation data was used to validate an Artificial Neural Network model which was developed using various meterological data from 2011-2015.

  7. Applications of Deep Neural Networks in a Top Quark Mass Measurement at the LHC

    CERN Document Server

    Lange, Torben; Kasieczka, Gregor

    2018-01-01

    In this analysis the usage of deep neural networks for an improved event selection forthe top-quark-mass measurement in the t¯ muon+jets channel for events at the CMS ext√periment for the LHC run II with a center of mass energy s = 13 TeV was investigated.The composition of the event selection with respect to different jet-assignment permutationtypes was found to have a strong influence on the systematic uncertainty of the top-quarkmass measurement. A selection based on the output of neural network trained on classifyingevent permutations of the t¯ muon+jets final state into these permutation types could thentbe used to improve the systematical uncertainty of the current mass measurement from asystematical uncertainty of around 630 MeV to 560 MeV.

  8. Measuring the default risk of sovereign debt from the perspective of network

    Science.gov (United States)

    Chuang, Hongwei; Ho, Hwai-Chung

    2013-05-01

    Recently, there has been a growing interest in network research, especially in the fields of biology, computer science, and sociology. It is natural to address complex financial issues such as the European sovereign debt crisis from the perspective of network. In this article, we construct a network model according to the debt-credit relations instead of using the conventional methodology to measure the default risk. Based on the model, a risk index is examined using the quarterly report of consolidated foreign claims from the Bank for International Settlements (BIS) and debt/GDP ratios among these reporting countries. The empirical results show that this index can help the regulators and practitioners not only to determine the status of interconnectivity but also to point out the degree of the sovereign debt default risk. Our approach sheds new light on the investigation of quantifying the systemic risk.

  9. Measurement of anthropogenic radionuclides in the atmosphere with a radionuclide monitoring network for nuclear tests

    International Nuclear Information System (INIS)

    Yonezawa, Chushiro; Yamamoto, Yoichi

    2011-01-01

    A worldwide radionuclide monitoring network for nuclear tests has detected the anthropogenic radioactive materials released in the atmosphere due to the accident of the Fukushima Daiichi Nuclear Power Plant impacted by the Great East Japan Earthquake on March 11, 2011. After four months have passed since the accident occurred, most overseas stations do not detect the radionuclides of Fukushima origin any more. The Takasaki station in Japan, however, is still detecting them every day. This paper describes radionuclide monitoring stations and the network of them as part of the International Monitoring System (IMS) in the Comprehensive Nuclear Test Ban Treaty (CTBT), as well as the measurement results of radionuclide particulates and radioactive isotopes of xenon released from the Fukushima Daiichi Nuclear Power Plant with the monitoring network. (J.P.N.)

  10. On the feasibility of measuring urban air pollution by wireless distributed sensor networks.

    Science.gov (United States)

    Moltchanov, Sharon; Levy, Ilan; Etzion, Yael; Lerner, Uri; Broday, David M; Fishbain, Barak

    2015-01-01

    Accurate evaluation of air pollution on human-wellbeing requires high-resolution measurements. Standard air quality monitoring stations provide accurate pollution levels but due to their sparse distribution they cannot capture the highly resolved spatial variations within cities. Similarly, dedicated field campaigns can use tens of measurement devices and obtain highly dense spatial coverage but normally deployment has been limited to short periods of no more than few weeks. Nowadays, advances in communication and sensory technologies enable the deployment of dense grids of wireless distributed air monitoring nodes, yet their sensor ability to capture the spatiotemporal pollutant variability at the sub-neighborhood scale has never been thoroughly tested. This study reports ambient measurements of gaseous air pollutants by a network of six wireless multi-sensor miniature nodes that have been deployed in three urban sites, about 150 m apart. We demonstrate the network's capability to capture spatiotemporal concentration variations at an exceptional fine resolution but highlight the need for a frequent in-situ calibration to maintain the consistency of some sensors. Accordingly, a procedure for a field calibration is proposed and shown to improve the system's performance. Overall, our results support the compatibility of wireless distributed sensor networks for measuring urban air pollution at a sub-neighborhood spatial resolution, which suits the requirement for highly spatiotemporal resolved measurements at the breathing-height when assessing exposure to urban air pollution. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Integration of neural networks with fuzzy reasoning for measuring operational parameters in a nuclear reactor

    International Nuclear Information System (INIS)

    Ikonomopoulos, A.; Tsoukalas, L.H.

    1993-01-01

    A novel approach is described for measuring variables with operational significance in a complex system such as a nuclear reactor. The methodology is based on the integration of artificial neural networks with fuzzy reasoning. Neural networks are used to map dynamic time series to a set of user-defined linguistic labels called fuzzy values. The process takes place in a manner analogous to that of measurement. Hence, the entire procedure is referred to as virtual measurement and its software implementation as a virtual measuring device. An optimization algorithm based on information criteria and fuzzy algebra augments the process and assists in the identification of different states of the monitored parameter. The proposed technique is applied for monitoring parameters such as performance, valve position, transient type, and reactivity. The results obtained from the application of the neural network-fuzzy reasoning integration in a high power research reactor clearly demonstrate the excellent tolerance of the virtual measuring device to faulty signals as well as its ability to accommodate noisy inputs

  12. Design of a Thermoacoustic Sensor for Low Intensity Ultrasound Measurements Based on an Artificial Neural Network.

    Science.gov (United States)

    Xing, Jida; Chen, Jie

    2015-06-23

    In therapeutic ultrasound applications, accurate ultrasound output intensities are crucial because the physiological effects of therapeutic ultrasound are very sensitive to the intensity and duration of these applications. Although radiation force balance is a benchmark technique for measuring ultrasound intensity and power, it is costly, difficult to operate, and compromised by noise vibration. To overcome these limitations, the development of a low-cost, easy to operate, and vibration-resistant alternative device is necessary for rapid ultrasound intensity measurement. Therefore, we proposed and validated a novel two-layer thermoacoustic sensor using an artificial neural network technique to accurately measure low ultrasound intensities between 30 and 120 mW/cm2. The first layer of the sensor design is a cylindrical absorber made of plexiglass, followed by a second layer composed of polyurethane rubber with a high attenuation coefficient to absorb extra ultrasound energy. The sensor determined ultrasound intensities according to a temperature elevation induced by heat converted from incident acoustic energy. Compared with our previous one-layer sensor design, the new two-layer sensor enhanced the ultrasound absorption efficiency to provide more rapid and reliable measurements. Using a three-dimensional model in the K-wave toolbox, our simulation of the ultrasound propagation process demonstrated that the two-layer design is more efficient than the single layer design. We also integrated an artificial neural network algorithm to compensate for the large measurement offset. After obtaining multiple parameters of the sensor characteristics through calibration, the artificial neural network is built to correct temperature drifts and increase the reliability of our thermoacoustic measurements through iterative training about ten seconds. The performance of the artificial neural network method was validated through a series of experiments. Compared to our previous

  13. Active self-testing noise measurement sensors for large-scale environmental sensor networks.

    Science.gov (United States)

    Domínguez, Federico; Cuong, Nguyen The; Reinoso, Felipe; Touhafi, Abdellah; Steenhaut, Kris

    2013-12-13

    Large-scale noise pollution sensor networks consist of hundreds of spatially distributed microphones that measure environmental noise. These networks provide historical and real-time environmental data to citizens and decision makers and are therefore a key technology to steer environmental policy. However, the high cost of certified environmental microphone sensors render large-scale environmental networks prohibitively expensive. Several environmental network projects have started using off-the-shelf low-cost microphone sensors to reduce their costs, but these sensors have higher failure rates and produce lower quality data. To offset this disadvantage, we developed a low-cost noise sensor that actively checks its condition and indirectly the integrity of the data it produces. The main design concept is to embed a 13 mm speaker in the noise sensor casing and, by regularly scheduling a frequency sweep, estimate the evolution of the microphone's frequency response over time. This paper presents our noise sensor's hardware and software design together with the results of a test deployment in a large-scale environmental network in Belgium. Our middle-range-value sensor (around €50) effectively detected all experienced malfunctions, in laboratory tests and outdoor deployments, with a few false positives. Future improvements could further lower the cost of our sensor below €10.

  14. CÆLIS: software for assimilation, management and processing data of an atmospheric measurement network

    Science.gov (United States)

    Fuertes, David; Toledano, Carlos; González, Ramiro; Berjón, Alberto; Torres, Benjamín; Cachorro, Victoria E.; de Frutos, Ángel M.

    2018-02-01

    Given the importance of the atmospheric aerosol, the number of instruments and measurement networks which focus on its characterization are growing. Many challenges are derived from standardization of protocols, monitoring of the instrument status to evaluate the network data quality and manipulation and distribution of large volume of data (raw and processed). CÆLIS is a software system which aims at simplifying the management of a network, providing tools by monitoring the instruments, processing the data in real time and offering the scientific community a new tool to work with the data. Since 2008 CÆLIS has been successfully applied to the photometer calibration facility managed by the University of Valladolid, Spain, in the framework of Aerosol Robotic Network (AERONET). Thanks to the use of advanced tools, this facility has been able to analyze a growing number of stations and data in real time, which greatly benefits the network management and data quality control. The present work describes the system architecture of CÆLIS and some examples of applications and data processing.

  15. PAFit: A Statistical Method for Measuring Preferential Attachment in Temporal Complex Networks.

    Directory of Open Access Journals (Sweden)

    Thong Pham

    Full Text Available Preferential attachment is a stochastic process that has been proposed to explain certain topological features characteristic of complex networks from diverse domains. The systematic investigation of preferential attachment is an important area of research in network science, not only for the theoretical matter of verifying whether this hypothesized process is operative in real-world networks, but also for the practical insights that follow from knowledge of its functional form. Here we describe a maximum likelihood based estimation method for the measurement of preferential attachment in temporal complex networks. We call the method PAFit, and implement it in an R package of the same name. PAFit constitutes an advance over previous methods primarily because we based it on a nonparametric statistical framework that enables attachment kernel estimation free of any assumptions about its functional form. We show this results in PAFit outperforming the popular methods of Jeong and Newman in Monte Carlo simulations. What is more, we found that the application of PAFit to a publically available Flickr social network dataset yielded clear evidence for a deviation of the attachment kernel from the popularly assumed log-linear form. Independent of our main work, we provide a correction to a consequential error in Newman's original method which had evidently gone unnoticed since its publication over a decade ago.

  16. Non-Contact Plant Growth Measurement Method and System Based on Ubiquitous Sensor Network Technologies

    Directory of Open Access Journals (Sweden)

    Intae Ryoo

    2011-04-01

    Full Text Available This paper proposes a non-contact plant growth measurement system using infrared sensors based on the ubiquitous sensor network (USN technology. The proposed system measures plant growth parameters such as the stem radius of plants using real-time non-contact methods, and generates diameter, cross-sectional area and thickening form of plant stems using this measured data. Non-contact sensors have been used not to cause any damage to plants during measurement of the growth parameters. Once the growth parameters are measured, they are transmitted to a remote server using the sensor network technology and analyzed in the application program server. The analyzed data are then provided for administrators and a group of interested users. The proposed plant growth measurement system has been designed and implemented using fixed-type and rotary-type infrared sensor based measurement methods and devices. Finally, the system performance is compared and verified with the measurement data that have been obtained by practical field experiments.

  17. Analysis on the dynamic error for optoelectronic scanning coordinate measurement network

    Science.gov (United States)

    Shi, Shendong; Yang, Linghui; Lin, Jiarui; Guo, Siyang; Ren, Yongjie

    2018-01-01

    Large-scale dynamic three-dimension coordinate measurement technique is eagerly demanded in equipment manufacturing. Noted for advantages of high accuracy, scale expandability and multitask parallel measurement, optoelectronic scanning measurement network has got close attention. It is widely used in large components jointing, spacecraft rendezvous and docking simulation, digital shipbuilding and automated guided vehicle navigation. At present, most research about optoelectronic scanning measurement network is focused on static measurement capacity and research about dynamic accuracy is insufficient. Limited by the measurement principle, the dynamic error is non-negligible and restricts the application. The workshop measurement and positioning system is a representative which can realize dynamic measurement function in theory. In this paper we conduct deep research on dynamic error resources and divide them two parts: phase error and synchronization error. Dynamic error model is constructed. Based on the theory above, simulation about dynamic error is carried out. Dynamic error is quantized and the rule of volatility and periodicity has been found. Dynamic error characteristics are shown in detail. The research result lays foundation for further accuracy improvement.

  18. Technical Note: Novel method for water vapour monitoring using wireless communication networks measurements

    Directory of Open Access Journals (Sweden)

    N. David

    2009-04-01

    Full Text Available We propose a new technique that overcomes the obstacles of the existing methods for monitoring near-surface water vapour, by estimating humidity from data collected through existing wireless communication networks.

    Weather conditions and atmospheric phenomena affect the electromagnetic channel, causing attenuations to the radio signals. Thus, wireless communication networks are in effect built-in environmental monitoring facilities. The wireless microwave links, used in these networks, are widely deployed by cellular providers for backhaul communication between base stations, a few tens of meters above ground level. As a result, if all available measurements are used, the proposed method can provide moisture observations with high spatial resolution and potentially high temporal resolution. Further, the implementation cost is minimal, since the data used are already collected and saved by the cellular operators. In addition – many of these links are installed in areas where access is difficult such as orographic terrain and complex topography. As such, our method enables measurements in places that have been hard to measure in the past, or have never been measured before. The technique is restricted to weather conditions which exclude rain, fog or clouds along the propagation path. Strong winds that may cause movement of the link transmitter or receiver (or both may also interfere with the ability to conduct accurate measurements.

    We present results from real-data measurements taken from two microwave links used in a backhaul cellular network that show convincing correlation to surface station humidity measurements. The measurements were taken daily in two sites, one in northern Israel (28 measurements, the other in central Israel (29 measurements. The correlation between the microwave link measurements and the humidity gauges were 0.9 and 0.82 for the north and central sites, respectively. The Root Mean Square Differences

  19. Comparing intermittency and network measurements of words and their dependence on authorship

    International Nuclear Information System (INIS)

    Amancio, Diego Raphael; Oliveira, Osvaldo N Jr; Fontoura Costa, Luciano da; Altmann, Eduardo G

    2011-01-01

    Many features of texts and languages can now be inferred from statistical analyses using concepts from complex networks and dynamical systems. In this paper, we quantify how topological properties of word co-occurrence networks and intermittency (or burstiness) in word distribution depend on the style of authors. Our database contains 40 books by eight authors who lived in the nineteenth and twentieth centuries, for which the following network measurements were obtained: the clustering coefficient, average shortest path lengths and betweenness. We found that the two factors with stronger dependence on authors were skewness in the distribution of word intermittency and the average shortest paths. Other factors such as betweenness and Zipf's law exponent show only weak dependence on authorship. Also assessed was the contribution from each measurement to authorship recognition using three machine learning methods. The best performance was about 65% accuracy upon combining complex networks and intermittency features with the nearest-neighbor algorithm of automatic authorship. From a detailed analysis of the interdependence of the various metrics, it is concluded that the methods used here are complementary for providing short- and long-scale perspectives on texts, which are useful for applications such as the identification of topical words and information retrieval. (paper)

  20. A network centrality measure framework for analyzing urban traffic flow: A case study of Wuhan, China

    Science.gov (United States)

    Zhao, Shuangming; Zhao, Pengxiang; Cui, Yunfan

    2017-07-01

    In this paper, we propose an improved network centrality measure framework that takes into account both the topological characteristics and the geometric properties of a road network in order to analyze urban traffic flow in relation to different modes: intersection, road, and community, which correspond to point mode, line mode, and area mode respectively. Degree, betweenness, and PageRank centralities are selected as the analysis measures, and GPS-enabled taxi trajectory data is used to evaluate urban traffic flow. The results show that the mean value of the correlation coefficients between the modified degree, the betweenness, and the PageRank centralities and the traffic flow in all periods are higher than the mean value of the correlation coefficients between the conventional degree, the betweenness, the PageRank centralities and the traffic flow at different modes; this indicates that the modified measurements, for analyzing traffic flow, are superior to conventional centrality measurements. This study helps to shed light into the understanding of urban traffic flow in relation to different modes from the perspective of complex networks.

  1. Weighted radial dimension: an improved fractal measurement for highway transportation networks distribution

    Science.gov (United States)

    Feng, Yongjiu; Liu, Miaolong; Tong, Xiaohua

    2007-06-01

    An improved fractal measurement, the weighted radial dimension, is put forward for highway transportation networks distribution. The radial dimension (DL), originated from subway investigation in Stuttgart, is a fractal measurement for transportation systems under ideal assumption considering all the network lines to be homogeneous curves, ignoring the difference on spatial structure, quality and level, especially the highway networks. Considering these defects of radial dimension, an improved fractal measurement called weighted radial dimension (D WL) is introduced and the transportation system in Guangdong province is studied in detail using this novel method. Weighted radial dimensions are measured and calculated, and the spatial structure, intensity and connectivity of transportation networks are discussed in Guangdong province and the four sub-areas: the Pearl River Delta area, the East Costal area, the West Costal area and the Northern Guangdong area. In Guangdong province, the fractal spatial pattern characteristics of transportation system vary remarkably: it is the highest in the Pearl River Delta area, moderate in Costal area and lowest in the Northern Guangdong area. With the Pearl River Delta area as the centre, the weighted radial dimensions decrease with the distance increasing, while the decline level is smaller in the costal area and greater in the Northern Guangdong province. By analysis of the conic of highway density, it is recognized that the density decrease with the distance increasing from the calculation centre (Guangzhou), demonstrating the same trend as weighted radial dimensions shown. Evidently, the improved fractal measurement, weighted radial dimension, is an indictor describing the characteristics of highway transportation system more effectively and accurately.

  2. Analysing the Correlation between Social Network Analysis Measures and Performance of Students in Social Network-Based Engineering Education

    Science.gov (United States)

    Putnik, Goran; Costa, Eric; Alves, Cátia; Castro, Hélio; Varela, Leonilde; Shah, Vaibhav

    2016-01-01

    Social network-based engineering education (SNEE) is designed and implemented as a model of Education 3.0 paradigm. SNEE represents a new learning methodology, which is based on the concept of social networks and represents an extended model of project-led education. The concept of social networks was applied in the real-life experiment,…

  3. Advanced Measurements of the Aggregation Capability of the MPT Network Layer Multipath Communication Library

    Directory of Open Access Journals (Sweden)

    Gábor Lencse

    2015-05-01

    Full Text Available The MPT network layer multipath communicationlibrary is a novel solution for several problems including IPv6transition, reliable data transmission using TCP, real-time transmissionusing UDP and also wireless network layer routingproblems. MPT can provide an IPv4 or an IPv6 tunnel overone or more IPv4 or IPv6 communication channels. MPT canalso aggregate the capacity of multiple physical channels. In thispaper, the channel aggregation capability of the MPT libraryis measured up to twelve 100Mbps speed channels. Differentscenarios are used: both IPv4 and IPv6 are used as the underlyingand also as the encapsulated protocols and also both UDP andTCP are used as transport protocols. In addition, measurementsare taken with both 32-bit and 64-bit version of the MPT library.In all cases, the number of the physical channels is increased from1 to 12 and the aggregated throughput is measured.

  4. Neural network modeling of air pollution in tunnels according to indirect measurements

    International Nuclear Information System (INIS)

    Kaverzneva, T; Lazovskaya, T; Tarkhov, D; Vasilyev, A

    2016-01-01

    The article deals with the problem of providing the necessary parameters of air of the working area in dead-end tunnels in the case of ventilation systems powered off. An ill-posed initialboundary problem for the diffusion equation is used as a mathematical model for a description and analysis of mass transfer processes in the tunnel. The neural network approach is applied to construct an approximate solution (regularization) of the identification problem in the case of the approximate measurement data and the set of interval parameters of the modeled system. Two types of model measurements included binary data are considered. The direct problem solution and the inverse problem regularization for the offered neural network approach are constructed uniformly. (paper)

  5. Field measurements and guidelines for the application of wireless sensor networks to the environment and security.

    Science.gov (United States)

    Gil Jiménez, Víctor P; Armada, Ana García

    2009-01-01

    Frequently, Wireless Sensor Networks (WSN) are designed focusing on applications and omitting transmission problems in these wireless networks. In this paper, we present a measurement campaign that has been carried out using one of the most commonly used WSN platforms, the micaZ from Crossbow(©). Based on these measurements, some guidelines to deploy a robust and reliable WSN are provided. The results are focused on security and environmental applications but can also be extrapolated to other scenarios. A main conclusion that can be extracted is that, from the transmission point of view, a dense WSN is one of the best choices to overcome many of the transmission problems such as the existence of a transitional region, redundance, forwarding, obstructions or interference with other systems.

  6. Detecting earthquakes over a seismic network using single-station similarity measures

    Science.gov (United States)

    Bergen, Karianne J.; Beroza, Gregory C.

    2018-06-01

    New blind waveform-similarity-based detection methods, such as Fingerprint and Similarity Thresholding (FAST), have shown promise for detecting weak signals in long-duration, continuous waveform data. While blind detectors are capable of identifying similar or repeating waveforms without templates, they can also be susceptible to false detections due to local correlated noise. In this work, we present a set of three new methods that allow us to extend single-station similarity-based detection over a seismic network; event-pair extraction, pairwise pseudo-association, and event resolution complete a post-processing pipeline that combines single-station similarity measures (e.g. FAST sparse similarity matrix) from each station in a network into a list of candidate events. The core technique, pairwise pseudo-association, leverages the pairwise structure of event detections in its network detection model, which allows it to identify events observed at multiple stations in the network without modeling the expected moveout. Though our approach is general, we apply it to extend FAST over a sparse seismic network. We demonstrate that our network-based extension of FAST is both sensitive and maintains a low false detection rate. As a test case, we apply our approach to 2 weeks of continuous waveform data from five stations during the foreshock sequence prior to the 2014 Mw 8.2 Iquique earthquake. Our method identifies nearly five times as many events as the local seismicity catalogue (including 95 per cent of the catalogue events), and less than 1 per cent of these candidate events are false detections.

  7. Evaluation of Data Security Measures in a Network Environment Towards Developing Cooperate Data Security Guidelines

    OpenAIRE

    Ayub Hussein Shirandula; Dr. G. Wanyembi; Mr. Maina karume

    2012-01-01

    Data security in a networked environment is a topic that has become significant in organizations. As companies and organizations rely more on technology to run their businesses, connecting system to each other in different departments for efficiency data security is the concern for administrators. This research assessed the data security measures put in place at Mumias Sugar Company and the effort it was using to protect its data. The researcher also highlighted major security issues that wer...

  8. Measuring Long-Term Impact Based on Network Centrality: Unraveling Cinematic Citations

    Science.gov (United States)

    Spitz, Andreas; Horvát, Emőke-Ágnes

    2014-01-01

    Traditional measures of success for film, such as box-office revenue and critical acclaim, lack the ability to quantify long-lasting impact and depend on factors that are largely external to the craft itself. With the growing number of films that are being created and large-scale data becoming available through crowd-sourced online platforms, an endogenous measure of success that is not reliant on manual appraisal is of increasing importance. In this article we propose such a ranking method based on a combination of centrality indices. We apply the method to a network that contains several types of citations between more than 40,000 international feature films. From this network we derive a list of milestone films, which can be considered to constitute the foundations of cinema. In a comparison to various existing lists of ‘greatest’ films, such as personal favourite lists, voting lists, lists of individual experts, and lists deduced from expert polls, the selection of milestone films is more diverse in terms of genres, actors, and main creators. Our results shed light on the potential of a systematic quantitative investigation based on cinematic influences in identifying the most inspiring creations in world cinema. In a broader perspective, we introduce a novel research question to large-scale citation analysis, one of the most intriguing topics that have been at the forefront of scientific enquiries for the past fifty years and have led to the development of various network analytic methods. In doing so, we transfer widely studied approaches from citation analysis to the the newly emerging field of quantification efforts in the arts. The specific contribution of this paper consists in modelling the multidimensional cinematic references as a growing multiplex network and in developing a methodology for the identification of central films in this network. PMID:25295877

  9. Measuring long-term impact based on network centrality: unraveling cinematic citations.

    Directory of Open Access Journals (Sweden)

    Andreas Spitz

    Full Text Available Traditional measures of success for film, such as box-office revenue and critical acclaim, lack the ability to quantify long-lasting impact and depend on factors that are largely external to the craft itself. With the growing number of films that are being created and large-scale data becoming available through crowd-sourced online platforms, an endogenous measure of success that is not reliant on manual appraisal is of increasing importance. In this article we propose such a ranking method based on a combination of centrality indices. We apply the method to a network that contains several types of citations between more than 40,000 international feature films. From this network we derive a list of milestone films, which can be considered to constitute the foundations of cinema. In a comparison to various existing lists of 'greatest' films, such as personal favourite lists, voting lists, lists of individual experts, and lists deduced from expert polls, the selection of milestone films is more diverse in terms of genres, actors, and main creators. Our results shed light on the potential of a systematic quantitative investigation based on cinematic influences in identifying the most inspiring creations in world cinema. In a broader perspective, we introduce a novel research question to large-scale citation analysis, one of the most intriguing topics that have been at the forefront of scientific enquiries for the past fifty years and have led to the development of various network analytic methods. In doing so, we transfer widely studied approaches from citation analysis to the the newly emerging field of quantification efforts in the arts. The specific contribution of this paper consists in modelling the multidimensional cinematic references as a growing multiplex network and in developing a methodology for the identification of central films in this network.

  10. Realization of High Dynamic Range Imaging in the GLORIA Network and Its Effect on Astronomical Measurement

    Directory of Open Access Journals (Sweden)

    Stanislav Vítek

    2016-01-01

    Full Text Available Citizen science project GLORIA (GLObal Robotic-telescopes Intelligent Array is a first free- and open-access network of robotic telescopes in the world. It provides a web-based environment where users can do research in astronomy by observing with robotic telescopes and/or by analyzing data that other users have acquired with GLORIA or from other free-access databases. Network of 17 telescopes allows users to control selected telescopes in real time or schedule any more demanding observation. This paper deals with new opportunity that GLORIA project provides to teachers and students of various levels of education. At the moment, there are prepared educational materials related to events like Sun eclipse (measuring local atmosphere changes, Aurora Borealis (calculation of Northern Lights height, or transit of Venus (measurement of the Earth-Sun distance. Student should be able to learn principles of CCD imaging, spectral analysis, basic calibration like dark frames subtraction, or advanced methods of noise suppression. Every user of the network can design his own experiment. We propose advanced experiment aimed at obtaining astronomical image data with high dynamic range. We also introduce methods of objective image quality evaluation in order to discover how HDR methods are affecting astronomical measurements.

  11. Two-level Robust Measurement Fusion Kalman Filter for Clustering Sensor Networks

    Institute of Scientific and Technical Information of China (English)

    ZHANG Peng; QI Wen-Juan; DENG Zi-Li

    2014-01-01

    This paper investigates the distributed fusion Kalman filtering over clustering sensor networks. The sensor network is partitioned as clusters by the nearest neighbor rule and each cluster consists of sensing nodes and cluster-head. Using the minimax robust estimation principle, based on the worst-case conservative system with the conservative upper bounds of noise variances, two-level robust measurement fusion Kalman filter is presented for the clustering sensor network systems with uncertain noise variances. It can significantly reduce the communication load and save energy when the number of sensors is very large. A Lyapunov equation approach for the robustness analysis is presented, by which the robustness of the local and fused Kalman filters is proved. The concept of the robust accuracy is presented, and the robust accuracy relations among the local and fused robust Kalman filters are proved. It is proved that the robust accuracy of the two-level weighted measurement fuser is equal to that of the global centralized robust fuser and is higher than those of each local robust filter and each local weighted measurement fuser. A simulation example shows the correctness and effectiveness of the proposed results.

  12. Exploring Vietnamese co-authorship patterns in social sciences with basic network measures of 2008-2017 Scopus data.

    Science.gov (United States)

    Ho, Tung Manh; Nguyen, Ha Viet; Vuong, Thu-Trang; Dam, Quang-Minh; Pham, Hiep-Hung; Vuong, Quan-Hoang

    2017-01-01

    Background: Collaboration is a common occurrence among Vietnamese scientists; however, insights into Vietnamese scientific collaborations have been scarce. On the other hand, the application of social network analysis in studying science collaboration has gained much attention all over the world. The technique could be employed to explore Vietnam's scientific community. Methods: This paper employs network theory to explore characteristics of a network of 412 Vietnamese social scientists whose papers can be found indexed in the Scopus database. Two basic network measures, density and clustering coefficient, were taken, and the entire network was studied in comparison with two of its largest components. Results: The networks connections are very sparse, with a density of only 0.47%, while the clustering coefficient is very high (58.64%). This suggests an inefficient dissemination of information, knowledge, and expertise in the network. Secondly, the disparity in levels of connection among individuals indicates that the network would easily fall apart if a few highly-connected nodes are removed. Finally, the two largest components of the network were found to differ from the entire networks in terms of measures and were both led by the most productive and well-connected researchers. Conclusions: High clustering and low density seems to be tied to inefficient dissemination of expertise among Vietnamese social scientists, and consequently low scientific output. Also low in robustness, the network shows the potential of an intellectual elite composed of well-connected, productive, and socially significant individuals.

  13. Full Scale Earth Fault Experiments on 10 kV laboratory network with comparative Measurements on Conventional CT's and VT's

    DEFF Research Database (Denmark)

    Sørensen, Stefan; Nielsen, Hans Ove; Bak-Jensen, Birgitte

    2002-01-01

    In this paper we present a result of a full scale earth fault carried out on the 10 kV research/laboratory distribution network at Kyndbyvaerket Denmark in May 2001. The network is compensated through a Petersen-Coil and current and voltage measurements were measured on conventional current....... The necessity of high bandwidth measurement equipment for earth fault measurements on compensated distribution networks can be undermined, since it will be shown that the transient signal transfer through conventional CT?s and VT?s for further signal analysis is sufficient. Caused the inadequacy three phase...

  14. Variances as order parameter and complexity measure for random Boolean networks

    International Nuclear Information System (INIS)

    Luque, Bartolo; Ballesteros, Fernando J; Fernandez, Manuel

    2005-01-01

    Several order parameters have been considered to predict and characterize the transition between ordered and disordered phases in random Boolean networks, such as the Hamming distance between replicas or the stable core, which have been successfully used. In this work, we propose a natural and clear new order parameter: the temporal variance. We compute its value analytically and compare it with the results of numerical experiments. Finally, we propose a complexity measure based on the compromise between temporal and spatial variances. This new order parameter and its related complexity measure can be easily applied to other complex systems

  15. Variances as order parameter and complexity measure for random Boolean networks

    Energy Technology Data Exchange (ETDEWEB)

    Luque, Bartolo [Departamento de Matematica Aplicada y EstadIstica, Escuela Superior de Ingenieros Aeronauticos, Universidad Politecnica de Madrid, Plaza Cardenal Cisneros 3, Madrid 28040 (Spain); Ballesteros, Fernando J [Observatori Astronomic, Universitat de Valencia, Ed. Instituts d' Investigacio, Pol. La Coma s/n, E-46980 Paterna, Valencia (Spain); Fernandez, Manuel [Departamento de Matematica Aplicada y EstadIstica, Escuela Superior de Ingenieros Aeronauticos, Universidad Politecnica de Madrid, Plaza Cardenal Cisneros 3, Madrid 28040 (Spain)

    2005-02-04

    Several order parameters have been considered to predict and characterize the transition between ordered and disordered phases in random Boolean networks, such as the Hamming distance between replicas or the stable core, which have been successfully used. In this work, we propose a natural and clear new order parameter: the temporal variance. We compute its value analytically and compare it with the results of numerical experiments. Finally, we propose a complexity measure based on the compromise between temporal and spatial variances. This new order parameter and its related complexity measure can be easily applied to other complex systems.

  16. Neural networks for the dimensionality reduction of GOME measurement vector in the estimation of ozone profiles

    International Nuclear Information System (INIS)

    Del Frate, F.; Iapaolo, M.; Casadio, S.; Godin-Beekmann, S.; Petitdidier, M.

    2005-01-01

    Dimensionality reduction can be of crucial importance in the application of inversion schemes to atmospheric remote sensing data. In this study the problem of dimensionality reduction in the retrieval of ozone concentration profiles from the radiance measurements provided by the instrument Global Ozone Monitoring Experiment (GOME) on board of ESA satellite ERS-2 is considered. By means of radiative transfer modelling, neural networks and pruning algorithms, a complete procedure has been designed to extract the GOME spectral ranges most crucial for the inversion. The quality of the resulting retrieval algorithm has been evaluated by comparing its performance to that yielded by other schemes and co-located profiles obtained with lidar measurements

  17. A framework for performance measurement in university using extended network data envelopment analysis (DEA) structures

    Science.gov (United States)

    Kashim, Rosmaini; Kasim, Maznah Mat; Rahman, Rosshairy Abd

    2015-12-01

    Measuring university performance is essential for efficient allocation and utilization of educational resources. In most of the previous studies, performance measurement in universities emphasized the operational efficiency and resource utilization without investigating the university's ability to fulfill the needs of its stakeholders and society. Therefore, assessment of the performance of university should be separated into two stages namely efficiency and effectiveness. In conventional DEA analysis, a decision making unit (DMU) or in this context, a university is generally treated as a black-box which ignores the operation and interdependence of the internal processes. When this happens, the results obtained would be misleading. Thus, this paper suggest an alternative framework for measuring the overall performance of a university by incorporating both efficiency and effectiveness and applies network DEA model. The network DEA models are recommended because this approach takes into account the interrelationship between the processes of efficiency and effectiveness in the system. This framework also focuses on the university structure which is expanded from the hierarchical to form a series of horizontal relationship between subordinate units by assuming both intermediate unit and its subordinate units can generate output(s). Three conceptual models are proposed to evaluate the performance of a university. An efficiency model is developed at the first stage by using hierarchical network model. It is followed by an effectiveness model which take output(s) from the hierarchical structure at the first stage as a input(s) at the second stage. As a result, a new overall performance model is proposed by combining both efficiency and effectiveness models. Thus, once this overall model is realized and utilized, the university's top management can determine the overall performance of each unit more accurately and systematically. Besides that, the result from the network

  18. Advanced Soil Moisture Network Technologies; Developments in Collecting in situ Measurements for Remote Sensing Missions

    Science.gov (United States)

    Moghaddam, M.; Silva, A. R. D.; Akbar, R.; Clewley, D.

    2015-12-01

    The Soil moisture Sensing Controller And oPtimal Estimator (SoilSCAPE) wireless sensor network has been developed to support Calibration and Validation activities (Cal/Val) for large scale soil moisture remote sensing missions (SMAP and AirMOSS). The technology developed here also readily supports small scale hydrological studies by providing sub-kilometer widespread soil moisture observations. An extensive collection of semi-sparse sensor clusters deployed throughout north-central California and southern Arizona provide near real time soil moisture measurements. Such a wireless network architecture, compared to conventional single points measurement profiles, allows for significant and expanded soil moisture sampling. The work presented here aims at discussing and highlighting novel and new technology developments which increase in situ soil moisture measurements' accuracy, reliability, and robustness with reduced data delivery latency. High efficiency and low maintenance custom hardware have been developed and in-field performance has been demonstrated for a period of three years. The SoilSCAPE technology incorporates (a) intelligent sensing to prevent erroneous measurement reporting, (b) on-board short term memory for data redundancy, (c) adaptive scheduling and sampling capabilities to enhance energy efficiency. A rapid streamlined data delivery architecture openly provides distribution of in situ measurements to SMAP and AirMOSS cal/val activities and other interested parties.

  19. Design and Development of a Pressure Transmitter Using Modified Inductance Measuring Network and Bellow Sensor

    Directory of Open Access Journals (Sweden)

    Venkata Lakshmi Narayana K.

    2013-03-01

    Full Text Available In this paper, a pressure transmitter using a modified op-amp based network for inductance measurement using a bellow as sensor has been proposed to measure the pressure and to convert pressure changes in to an electrical current which can be transmitted to a remote indicator. The change in inductance due to change in pressure is measured by an improved modified operational amplifier based network. The proposed network permits offset inductance compensation of sensing coil and also minimizes the stray capacitance between sensing coil and ground using dummy inductor whose value equal to zero level inductance of sensing coil and op-amps with high input impedance. In the first part of experiment, a modified op-amp based inductance measuring circuit has been simulated using LabVIEW (Laboratory Virtual Instrument Engineering Workbench and studied with test inductance, and in the second part, the experimentation was done by replacing the test inductance with a sensing coil fitted to bellow by means of ferromagnetic wire for the measurement of pressure. It has been observed that the variation in gauge pressure from 0 to 70 psi having linear relationship with output ac voltage in the range of 0 to 85.0 mV. Corresponding to pressure variations, the ac output voltage further converted into an electric current of 4 to 20 mA for remote indication and control purpose. The investigations have been performed to sense air pressure of pressure tank fitted with pump piston. The experimental results are found to have good linearity of about ± 0.1 % and resolution.

  20. Networking

    OpenAIRE

    Rauno Lindholm, Daniel; Boisen Devantier, Lykke; Nyborg, Karoline Lykke; Høgsbro, Andreas; Fries, de; Skovlund, Louise

    2016-01-01

    The purpose of this project was to examine what influencing factor that has had an impact on the presumed increasement of the use of networking among academics on the labour market and how it is expressed. On the basis of the influence from globalization on the labour market it can be concluded that the globalization has transformed the labour market into a market based on the organization of networks. In this new organization there is a greater emphasis on employees having social qualificati...

  1. A non-contact shape measuring system using an artificial neural network

    International Nuclear Information System (INIS)

    Jeon, Woo Tae; Lee, Myung Chan; Koh, Duck Joon; Cho, Hyung Suck

    1996-01-01

    We developed a non-contact shape measuring device using computer image processing technology. We present a method of calibrating a CCD video camera and a laser range finder which is the most important step toward making an accurate shape measuring system. An artificial neural network is used for the calibration. Our measurement system is composed of a semiconductor laser, a CCD video camera, a personal computer, and a linear motion table. We think that the developed system could be used for measuring the change in shape of the spent nuclear fuel rod before and after irradiation which is one of the most important tasks for developing a better nuclear fuel. A radiation shield is suggested for the possible utilization of the range finder in radioactive environment

  2. Data Visualization and Analysis Tools for the Global Precipitation Measurement (GPM) Validation Network

    Science.gov (United States)

    Morris, Kenneth R.; Schwaller, Mathew

    2010-01-01

    The Validation Network (VN) prototype for the Global Precipitation Measurement (GPM) Mission compares data from the Tropical Rainfall Measuring Mission (TRMM) satellite Precipitation Radar (PR) to similar measurements from U.S. and international operational weather radars. This prototype is a major component of the GPM Ground Validation System (GVS). The VN provides a means for the precipitation measurement community to identify and resolve significant discrepancies between the ground radar (GR) observations and similar satellite observations. The VN prototype is based on research results and computer code described by Anagnostou et al. (2001), Bolen and Chandrasekar (2000), and Liao et al. (2001), and has previously been described by Morris, et al. (2007). Morris and Schwaller (2009) describe the PR-GR volume-matching algorithm used to create the VN match-up data set used for the comparisons. This paper describes software tools that have been developed for visualization and statistical analysis of the original and volume matched PR and GR data.

  3. Quantifying the value of redundant measurements at GCOS Reference Upper-Air Network sites

    Directory of Open Access Journals (Sweden)

    F. Madonna

    2014-11-01

    Full Text Available The potential for measurement redundancy to reduce uncertainty in atmospheric variables has not been investigated comprehensively for climate observations. We evaluated the usefulness of entropy and mutual correlation concepts, as defined in information theory, for quantifying random uncertainty and redundancy in time series of the integrated water vapour (IWV and water vapour mixing ratio profiles provided by five highly instrumented GRUAN (GCOS, Global Climate Observing System, Reference Upper-Air Network stations in 2010–2012. Results show that the random uncertainties on the IWV measured with radiosondes, global positioning system, microwave and infrared radiometers, and Raman lidar measurements differed by less than 8%. Comparisons of time series of IWV content from ground-based remote sensing instruments with in situ soundings showed that microwave radiometers have the highest redundancy with the IWV time series measured by radiosondes and therefore the highest potential to reduce the random uncertainty of the radiosondes time series. Moreover, the random uncertainty of a time series from one instrument can be reduced by ~ 60% by constraining the measurements with those from another instrument. The best reduction of random uncertainty is achieved by conditioning Raman lidar measurements with microwave radiometer measurements. Specific instruments are recommended for atmospheric water vapour measurements at GRUAN sites. This approach can be applied to the study of redundant measurements for other climate variables.

  4. Time Series Data Analysis of Wireless Sensor Network Measurements of Temperature.

    Science.gov (United States)

    Bhandari, Siddhartha; Bergmann, Neil; Jurdak, Raja; Kusy, Branislav

    2017-05-26

    Wireless sensor networks have gained significant traction in environmental signal monitoring and analysis. The cost or lifetime of the system typically depends on the frequency at which environmental phenomena are monitored. If sampling rates are reduced, energy is saved. Using empirical datasets collected from environmental monitoring sensor networks, this work performs time series analyses of measured temperature time series. Unlike previous works which have concentrated on suppressing the transmission of some data samples by time-series analysis but still maintaining high sampling rates, this work investigates reducing the sampling rate (and sensor wake up rate) and looks at the effects on accuracy. Results show that the sampling period of the sensor can be increased up to one hour while still allowing intermediate and future states to be estimated with interpolation RMSE less than 0.2 °C and forecasting RMSE less than 1 °C.

  5. The national network of measurements of radioactivity in the environment. Management report - 2010

    International Nuclear Information System (INIS)

    Leprieur, Fabrice; Chaptal-Gradoz, Nathalie; Wyckaert, Laure; Guldner, Bruno; Jaunet, Pierrick; Levelut, Marie-Noelle

    2010-01-01

    This report presents the objectives and challenges of the French national network for the measurement of radioactivity in the environment, its legal and regulatory context, its operation, its actors (ASN, IRSN and other actors). It proposes the moral report on the steering committee and work-groups. It describes the development of the information system: main stages, synthetic description, process from data transmission to edition on Internet sites, exploitation of the public Internet site, of the requester internet site, of hosting platforms, harmonization of transmitted data, planning for 2011. It presents the exploitation assessment for 2011: technical support activities, interactions between the IRSN and the national network information system host, and so on. The last part deals with communication and publication activities

  6. Automatic Leak Detection in Buried Plastic Pipes of Water Supply Networks by Means of Vibration Measurements

    Directory of Open Access Journals (Sweden)

    Alberto Martini

    2015-01-01

    Full Text Available The implementation of strategies for controlling water leaks is essential in order to reduce losses affecting distribution networks of drinking water. This paper focuses on leak detection by using vibration monitoring techniques. The long-term goal is the development of a system for automatic early detection of burst leaks in service pipes. An experimental campaign was started to measure vibrations transmitted along water pipes by real burst leaks occurring in actual water supply networks. The first experimental data were used for assessing the leak detection performance of a prototypal algorithm based on the calculation of the standard deviation of acceleration signals. The experimental campaign is here described and discussed. The proposed algorithm, enhanced by means of proper signal filtering techniques, was successfully tested on all monitored leaks, thus proving effective for leak detection purpose.

  7. Design of a Thermoacoustic Sensor for Low Intensity Ultrasound Measurements Based on an Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Jida Xing

    2015-06-01

    Full Text Available In therapeutic ultrasound applications, accurate ultrasound output intensities are crucial because the physiological effects of therapeutic ultrasound are very sensitive to the intensity and duration of these applications. Although radiation force balance is a benchmark technique for measuring ultrasound intensity and power, it is costly, difficult to operate, and compromised by noise vibration. To overcome these limitations, the development of a low-cost, easy to operate, and vibration-resistant alternative device is necessary for rapid ultrasound intensity measurement. Therefore, we proposed and validated a novel two-layer thermoacoustic sensor using an artificial neural network technique to accurately measure low ultrasound intensities between 30 and 120 mW/cm2. The first layer of the sensor design is a cylindrical absorber made of plexiglass, followed by a second layer composed of polyurethane rubber with a high attenuation coefficient to absorb extra ultrasound energy. The sensor determined ultrasound intensities according to a temperature elevation induced by heat converted from incident acoustic energy. Compared with our previous one-layer sensor design, the new two-layer sensor enhanced the ultrasound absorption efficiency to provide more rapid and reliable measurements. Using a three-dimensional model in the K-wave toolbox, our simulation of the ultrasound propagation process demonstrated that the two-layer design is more efficient than the single layer design. We also integrated an artificial neural network algorithm to compensate for the large measurement offset. After obtaining multiple parameters of the sensor characteristics through calibration, the artificial neural network is built to correct temperature drifts and increase the reliability of our thermoacoustic measurements through iterative training about ten seconds. The performance of the artificial neural network method was validated through a series of experiments. Compared

  8. Strategy of thunderstorm measurement with super dense ground-based observation network

    Science.gov (United States)

    Takahashi, Y.; Sato, M.

    2014-12-01

    It's not easy to understand the inside structure and developing process of thunderstorm only with existing meteorological instruments since its horizontal extent of the storm cell is sometimes smaller than an order of 10 km while one of the densest ground network in Japan, AMEDAS, consists of sites located every 17 km in average and the resolution of meteorological radar is 1-2 km in general. Even the X-band radar realizes the resolution of 250 m or larger. Here we suggest a new super dense observation network with simple and low cost sensors that can be used for measurement both of raindrop and vertical electric field change caused by cloud-to-ground lightning discharge. This sensor consists of two aluminum plates with a diameter of 10-20 cm. We carried out an observation campaign in summer of 2013 in the foothills of Mt. Yastugatake, Yamanashi and Nagano prefectures in Japan, installing 6 plate-type sensors at a distance of about 4 km. Horizontal location, height and charge amount of each lightning discharge are estimated successfully based on the information of electric field changes at several observing sites. Moreover, it was found that the thunderstorm has a very narrow structure well smaller than 300 m that cannot be measured by any other ways, counting the positive and negative pulses caused by attachment of raindrop to the sensor plate, respectively. We plan to construct a new super dense observation network in the north Kanto region, Japan, where the lightning activity is most prominent in summer Japan, distributing more than several tens of sensors at every 4 km or shorter, such as an order of 100 m at minimum. This kind of new type network will reveal the unknown fine structures of thunderstorms and open the door for constructing real time alert system of torrential rainfall and lightning stroke especially in the city area.

  9. Relative localization in wireless sensor networks for measurement of electric fields under HVDC transmission lines.

    Science.gov (United States)

    Cui, Yong; Wang, Qiusheng; Yuan, Haiwen; Song, Xiao; Hu, Xuemin; Zhao, Luxing

    2015-02-04

    In the wireless sensor networks (WSNs) for electric field measurement system under the High-Voltage Direct Current (HVDC) transmission lines, it is necessary to obtain the electric field distribution with multiple sensors. The location information of each sensor is essential to the correct analysis of measurement results. Compared with the existing approach which gathers the location information by manually labelling sensors during deployment, the automatic localization can reduce the workload and improve the measurement efficiency. A novel and practical range-free localization algorithm for the localization of one-dimensional linear topology wireless networks in the electric field measurement system is presented. The algorithm utilizes unknown nodes' neighbor lists based on the Received Signal Strength Indicator (RSSI) values to determine the relative locations of nodes. The algorithm is able to handle the exceptional situation of the output permutation which can effectively improve the accuracy of localization. The performance of this algorithm under real circumstances has been evaluated through several experiments with different numbers of nodes and different node deployments in the China State Grid HVDC test base. Results show that the proposed algorithm achieves an accuracy of over 96% under different conditions.

  10. Relative Localization in Wireless Sensor Networks for Measurement of Electric Fields under HVDC Transmission Lines

    Directory of Open Access Journals (Sweden)

    Yong Cui

    2015-02-01

    Full Text Available In the wireless sensor networks (WSNs for electric field measurement system under the High-Voltage Direct Current (HVDC transmission lines, it is necessary to obtain the electric field distribution with multiple sensors. The location information of each sensor is essential to the correct analysis of measurement results. Compared with the existing approach which gathers the location information by manually labelling sensors during deployment, the automatic localization can reduce the workload and improve the measurement efficiency. A novel and practical range-free localization algorithm for the localization of one-dimensional linear topology wireless networks in the electric field measurement system is presented. The algorithm utilizes unknown nodes’ neighbor lists based on the Received Signal Strength Indicator (RSSI values to determine the relative locations of nodes. The algorithm is able to handle the exceptional situation of the output permutation which can effectively improve the accuracy of localization. The performance of this algorithm under real circumstances has been evaluated through several experiments with different numbers of nodes and different node deployments in the China State Grid HVDC test base. Results show that the proposed algorithm achieves an accuracy of over 96% under different conditions.

  11. Analytic tools for investigating the structure of network reliability measures with regard to observation correlations

    Science.gov (United States)

    Prószyński, W.; Kwaśniak, M.

    2018-03-01

    A global measure of observation correlations in a network is proposed, together with the auxiliary indices related to non-diagonal elements of the correlation matrix. Based on the above global measure, a specific representation of the correlation matrix is presented, being the result of rigorously proven theorem formulated within the present research. According to the theorem, each positive definite correlation matrix can be expressed by a scale factor and a so-called internal weight matrix. Such a representation made it possible to investigate the structure of the basic reliability measures with regard to observation correlations. Numerical examples carried out for two test networks illustrate the structure of those measures that proved to be dependent on global correlation index. Also, the levels of global correlation are proposed. It is shown that one can readily find an approximate value of the global correlation index, and hence the correlation level, for the expected values of auxiliary indices being the only knowledge about a correlation matrix of interest. The paper is an extended continuation of the previous study of authors that was confined to the elementary case termed uniform correlation. The extension covers arbitrary correlation matrices and a structure of correlation effect.

  12. A Network Method of Measuring Affiliation-Based Peer Influence: Assessing the Influences of Teammates' Smoking on Adolescent Smoking

    Science.gov (United States)

    Fujimoto, Kayo; Unger, Jennifer B.; Valente, Thomas W.

    2012-01-01

    Using a network analytic framework, this study introduces a new method to measure peer influence based on adolescents' affiliations or 2-mode social network data. Exposure based on affiliations is referred to as the "affiliation exposure model." This study demonstrates the methodology using data on young adolescent smoking being influenced by…

  13. Determining the Most Vital Arcs Within a Multi-Mode Communication Network Using Set-Based Measures

    Science.gov (United States)

    2015-03-26

    as a way to measure reliability, thus providing a statistic for the resilience of a network. The connectivity or ability to communicate between pairs...pp. 955–969, 2006. 20. A. H. Dekker and B. D. Colbert, “Network robustness and graph topology,” in Proceedings of the 27th Australasian conference on

  14. Delaunay Triangulation as a New Coverage Measurement Method in Wireless Sensor Network

    Science.gov (United States)

    Chizari, Hassan; Hosseini, Majid; Poston, Timothy; Razak, Shukor Abd; Abdullah, Abdul Hanan

    2011-01-01

    Sensing and communication coverage are among the most important trade-offs in Wireless Sensor Network (WSN) design. A minimum bound of sensing coverage is vital in scheduling, target tracking and redeployment phases, as well as providing communication coverage. Some methods measure the coverage as a percentage value, but detailed information has been missing. Two scenarios with equal coverage percentage may not have the same Quality of Coverage (QoC). In this paper, we propose a new coverage measurement method using Delaunay Triangulation (DT). This can provide the value for all coverage measurement tools. Moreover, it categorizes sensors as ‘fat’, ‘healthy’ or ‘thin’ to show the dense, optimal and scattered areas. It can also yield the largest empty area of sensors in the field. Simulation results show that the proposed DT method can achieve accurate coverage information, and provides many tools to compare QoC between different scenarios. PMID:22163792

  15. Line width measurement below 60 nm using an optical interferometer and artificial neural network

    Science.gov (United States)

    See, Chung W.; Smith, Richard J.; Somekh, Michael G.; Yacoot, Andrew

    2007-03-01

    We have recently described a technique for optical line-width measurements. The system currently is capable of measuring line-width down to 60 nm with a precision of 2 nm, and potentially should be able to measure down to 10nm. The system consists of an ultra-stable interferometer and artificial neural networks (ANNs). The former is used to generate optical profiles which are input to the ANNs. The outputs of the ANNs are the desired sample parameters. Different types of samples have been tested with equally impressive results. In this paper we will discuss the factors that are essential to extend the application of the technique. Two of the factors are signal conditioning and sample classification. Methods, including principal component analysis, that are capable of performing these tasks will be considered.

  16. Inverse calculation of strain profiles from ETDR measurements using artificial neural networks

    Directory of Open Access Journals (Sweden)

    R. Höhne

    2017-12-01

    Full Text Available A novel carbon fibre sensor is developed for the spatially resolved strain measurement. A unique feature of the sensor is the fibre-break resistive measurement principle and the two-core transmission line design. The electrical time domain reflectometry (ETDR is used in order to realize a spatially resolved measurement of the electrical parameters of the sensor. In this contribution, the process of mapping between the ETDR signals to the existing strain profile is described. Artificial neural networks (ANNs are used to solve the inverse electromagnetic problem. The investigations were carried out with a sensor patch in a cantilever arm configuration. Overall, 136 experiments with varying strain distribution over the sensor length were performed to generate the necessary training data to learn the ANN model. The validation of the ANN highlights the feasibility as well as the current limits concerning the quantitative accuracy of mapping ETDR signals to strain profiles.

  17. Augmented Lagrange Programming Neural Network for Localization Using Time-Difference-of-Arrival Measurements.

    Science.gov (United States)

    Han, Zifa; Leung, Chi Sing; So, Hing Cheung; Constantinides, Anthony George

    2017-08-15

    A commonly used measurement model for locating a mobile source is time-difference-of-arrival (TDOA). As each TDOA measurement defines a hyperbola, it is not straightforward to compute the mobile source position due to the nonlinear relationship in the measurements. This brief exploits the Lagrange programming neural network (LPNN), which provides a general framework to solve nonlinear constrained optimization problems, for the TDOA-based localization. The local stability of the proposed LPNN solution is also analyzed. Simulation results are included to evaluate the localization accuracy of the LPNN scheme by comparing with the state-of-the-art methods and the optimality benchmark of Cramér-Rao lower bound.

  18. Mean and turbulent mass flux measurements in an idealised street network.

    Science.gov (United States)

    Carpentieri, Matteo; Robins, Alan G; Hayden, Paul; Santi, Edoardo

    2018-03-01

    Pollutant mass fluxes are rarely measured in the laboratory, especially their turbulent component. They play a major role in the dispersion of gases in urban areas and modern mathematical models often attempt some sort of parametrisation. An experimental technique to measure mean and turbulent fluxes in an idealised urban array was developed and applied to improve our understanding of how the fluxes are distributed in a dense street canyon network. As expected, horizontal advective scalar fluxes were found to be dominant compared with the turbulent components. This is an important result because it reduces the complexity in developing parametrisations for street network models. On the other hand, vertical mean and turbulent fluxes appear to be approximately of the same order of magnitude. Building height variability does not appear to affect the exchange process significantly, while the presence of isolated taller buildings upwind of the area of interest does. One of the most interesting results, again, is the fact that even very simple and regular geometries lead to complex advective patterns at intersections: parametrisations derived from measurements in simpler geometries are unlikely to capture the full complexity of a real urban area. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. The enerMENA meteorological network - Solar radiation measurements in the MENA region

    Science.gov (United States)

    Schüler, D.; Wilbert, S.; Geuder, N.; Affolter, R.; Wolfertstetter, F.; Prahl, C.; Röger, M.; Schroedter-Homscheidt, M.; Abdellatif, G.; Guizani, A. Allah; Balghouthi, M.; Khalil, A.; Mezrhab, A.; Al-Salaymeh, A.; Yassaa, N.; Chellali, F.; Draou, D.; Blanc, P.; Dubranna, J.; Sabry, O. M. K.

    2016-05-01

    For solar resource assessment of solar power plants and adjustment of satellite data, high accuracy measurement data of irradiance and ancillary meteorological data is needed. For the MENA region (Middle East and Northern Africa), which is of high importance for concentrating solar power applications, so far merely 2 publicly available ground measurement stations existed (BSRN network). This gap has been filled by ten stations in Morocco, Algeria, Tunisia, Egypt and Jordan. In this publication the data quality is analyzed by evaluating data completeness and the cleanliness of irradiance sensors in comparison for all of the stations. The pyrheliometers have an average cleanliness of 99.2 % for week-daily cleaning. This is a 5 times higher effort than for Rotating Shadowband Irradiometer (RSI) stations which even have a slightly higher average cleanliness of 99.3 % for weekly cleaning. Furthermore, RSI stations show a data completeness of 99.4 % compared to 93.6 % at the stations equipped with thermal sensors. The results of this analysis are used to derive conclusions concerning instrument choice and are hence also applicable to other solar radiation measurements outside the enerMENA network. It turns out that RSIs are the more reliable and robust choice in cases of high soiling, rare station visits for cleaning and maintenance, as usual in desert sites. Furthermore, annual direct normal and global horizontal irradiation as well as average meteorological parameters are calculated for all of the stations.

  20. Simple measurement-based admission control for DiffServ access networks

    Science.gov (United States)

    Lakkakorpi, Jani

    2002-07-01

    In order to provide good Quality of Service (QoS) in a Differentiated Services (DiffServ) network, a dynamic admission control scheme is definitely needed as an alternative to overprovisioning. In this paper, we present a simple measurement-based admission control (MBAC) mechanism for DiffServ-based access networks. Instead of using active measurements only or doing purely static bookkeeping with parameter-based admission control (PBAC), the admission control decisions are based on bandwidth reservations and periodically measured & exponentially averaged link loads. If any link load on the path between two endpoints is over the applicable threshold, access is denied. Link loads are periodically sent to Bandwidth Broker (BB) of the routing domain, which makes the admission control decisions. The information needed in calculating the link loads is retrieved from the router statistics. The proposed admission control mechanism is verified through simulations. Our results prove that it is possible to achieve very high bottleneck link utilization levels and still maintain good QoS.

  1. Maritime Aerosol Network optical depth measurements and comparison with satellite retrievals from various different sensors

    Science.gov (United States)

    Smirnov, Alexander; Petrenko, Maksym; Ichoku, Charles; Holben, Brent N.

    2017-10-01

    The paper reports on the current status of the Maritime Aerosol Network (MAN) which is a component of the Aerosol Robotic Network (AERONET). A public domain web-based data archive dedicated to MAN activity can be found at https://aeronet.gsfc.nasa.gov/new_web/maritime_aerosol_network.html . Since 2006 over 450 cruises were completed and the data archive consists of more than 6000 measurement days. In this work, we present MAN observations collocated with MODIS Terra, MODIS Aqua, MISR, POLDER, SeaWIFS, OMI, and CALIOP spaceborne aerosol products using a modified version of the Multi-Sensor Aerosol Products Sampling System (MAPSS) framework. Because of different spatio-temporal characteristics of the analyzed products, the number of MAN data points collocated with spaceborne retrievals varied between 1500 matchups for MODIS to 39 for CALIOP (as of August 2016). Despite these unavoidable sampling biases, latitudinal dependencies of AOD differences for all satellite sensors, except for SeaWIFS and POLDER, showed positive biases against ground truth (i.e. MAN) in the southern latitudes (<50° S), and substantial scatter in the Northern Atlantic "dust belt" (5°-15° N). Our analysis did not intend to determine whether satellite retrievals are within claimed uncertainty boundaries, but rather show where bias exists and corrections are needed.

  2. Self-powered information measuring wireless networks using the distribution of tasks within multicore processors

    Science.gov (United States)

    Zhuravska, Iryna M.; Koretska, Oleksandra O.; Musiyenko, Maksym P.; Surtel, Wojciech; Assembay, Azat; Kovalev, Vladimir; Tleshova, Akmaral

    2017-08-01

    The article contains basic approaches to develop the self-powered information measuring wireless networks (SPIM-WN) using the distribution of tasks within multicore processors critical applying based on the interaction of movable components - as in the direction of data transmission as wireless transfer of energy coming from polymetric sensors. Base mathematic model of scheduling tasks within multiprocessor systems was modernized to schedule and allocate tasks between cores of one-crystal computer (SoC) to increase energy efficiency SPIM-WN objects.

  3. AziSA: An architecture for underground measurement and control networks - 2nd CSIR Biennial Conference

    CSIR Research Space (South Africa)

    Stewart, R

    2008-11-01

    Full Text Available products from various manufacturers. SOLUTION The architecture that has been developed at the CSIR is called AziSA, an isiZulu word meaning ‘to inform’. The AziSA architecture AziSA is a specification for an open measurement and control network... for in-mine communications even if the link with the outside world is disrupted. This requirement for robustness implies that processing in the system must be distributed and not totally dependent on central coordination. Decisions should be made...

  4. Atmospheric conditions measured by a wireless sensor network on the local scale

    Science.gov (United States)

    Lengfeld, K.; Ament, F.

    2010-09-01

    Atmospheric conditions close to the surface, like temperature, wind speed and humidity, vary on small scales because of surface heterogeneities. Therefore, the traditional measuring approach of using a single, highly accurate station is of limited representativeness for a larger domain, because it is not able to determine these small scale variabilities. However, both the variability and the domain averages are important information for the development and validation of atmospheric models and soil-vegetation-atmosphere-transfer (SVAT) schemes. Due to progress in microelectronics it is possible to construct networks of comparably cheap meteorological stations with moderate accuracy. Such a network provides data in high spatial and temporal resolution. The EPFL Lausanne developed such a network called SensorScope, consisting of low cost autonomous stations. Each station observes air and surface temperature, humidity, wind direction and speed, incoming solar radiation, precipitation, soil moisture and soil temperature and sends the data via radio communication to a base station. This base station forwards the collected data via GSM/GPRS to a central server. The first measuring campaign took place within the FLUXPAT project in August 2009. We deployed 15 stations as a twin transect near Jülich, Germany. To test the quality of the low cost sensors we compared two of them to more accurate reference systems. It turned out, that although the network sensors are not highly accurate, the measurements are consistent. Consequently an analysis of the pattern of atmospheric conditions is feasible. The transect is 2.3 km long and covers different types of vegetation and a small river. Therefore, we analyse the influence of different land surfaces and the distance to the river on meteorological conditions. For example, we found a difference in air temperature of 0.8°C between the station closest to and the station farthest from the river. The decreasing relative humidity with

  5. A cost-effective measurement-device-independent quantum key distribution system for quantum networks

    Science.gov (United States)

    Valivarthi, Raju; Zhou, Qiang; John, Caleb; Marsili, Francesco; Verma, Varun B.; Shaw, Matthew D.; Nam, Sae Woo; Oblak, Daniel; Tittel, Wolfgang

    2017-12-01

    We experimentally realize a measurement-device-independent quantum key distribution (MDI-QKD) system. It is based on cost-effective and commercially available hardware such as distributed feedback lasers and field-programmable gate arrays that enable time-bin qubit preparation and time-tagging, and active feedback systems that allow for compensation of time-varying properties of photons after transmission through deployed fiber. We examine the performance of our system, and conclude that its design does not compromise performance. Our demonstration paves the way for MDI-QKD-based quantum networks in star-type topology that extend over more than 100 km distance.

  6. Research and development cooperation project on environmental measurement using laser radar in fiscal 1994 (environmental network); Kankyo keisokuyo laser radar no kaihatsu ni kansuru kenkyu kyoryoku (kankyo network)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-03-01

    Under the R and D of a laser radar for environmental measurement which are conducted in cooperation with Indonesia, the paper reported the R and D of the environmental network in fiscal 1994. Four field surveys were made, and the following were conducted: proposal of a technical system, adjustment of the Asian environmental information network with BPPT and LIPI which are organs on the Indonesian side, installation of/technical discussion on network equipment, etc. There is IPTEKNET as a plan of a nationwide network of the scientific technology information service in Indonesia. The analytical design phase of this system converged in 1992, and the predicted investment amount in the coming five years is expected to be 6.7 million US dollars. As the future Asian environmental information network work, planned are connection between BPPT and Tokyo CC and connection at BPPT between the Asian environmental information network and IPTEKNET. Network managers at sites are very skillful, and therefore, the thorough cooperative work is anticipated. 24 figs.

  7. Protein distance constraints predicted by neural networks and probability density functions

    DEFF Research Database (Denmark)

    Lund, Ole; Frimand, Kenneth; Gorodkin, Jan

    1997-01-01

    We predict interatomic C-α distances by two independent data driven methods. The first method uses statistically derived probability distributions of the pairwise distance between two amino acids, whilst the latter method consists of a neural network prediction approach equipped with windows taki...... method based on the predicted distances is presented. A homepage with software, predictions and data related to this paper is available at http://www.cbs.dtu.dk/services/CPHmodels/...

  8. Monitoring network for doserate-measurements with wireless datatransmitting in Baden-Wuerttemberg

    International Nuclear Information System (INIS)

    Aures, R.; Wenzel, H.

    2003-01-01

    In the environment of the nuclear power plants Philippsburg, Obrigheim and Neckarwestheim in Baden-Wuerttemberg there is a monitoring network with 90 stations. They are measuring the gamma-dose rate. In the meantime these monitoring stations are nearly 20 years old and now it is time to substitute old technology by a new one. The aim is a mix of monitoring stations with phone wire- and wireless data transmission (Skylink). Thinkable is a part of 50 % of Skylink-tubes in the monitoring network and some for mobile performance. The main aspect of the planned substitution is a second independent way of data transmission. Normally there are no problems for data transmission. But in case of emergency the data transmissions which depends from phone wires could be delayed if there are too much dates. So the second way, the way of wireless data transmissions becomes important. The Landesanstalt fuer Umweltschutz in Karlsruhe has bought a complete system from the company Genitron in Frankfurt/Main. The system (Skylink) consists of the receiver and the does rate-monitoring stations. Such a system was tested successfully in a region with many mountains and deep valleys. Since July 2000 the Skylink-system is performed in the ''Nuclear power monitoring system'' (KFUe) in Baden-Wuerttemberg. The receiver is on the Koenigstuhl (630 m) near Heidelberg. This is a very good position to receive the wireless transmitted dates from every monitoring station (Skylink Gammatracer) of the monitoring network. Now there are 27 Skylink Gammatracer spread in the monitoring network. At time they are placed near the dose rate tubes of the old monitoring stations for comparing the dose rates and they are working with best results. (orig.)

  9. BridgeRank: A novel fast centrality measure based on local structure of the network

    Science.gov (United States)

    Salavati, Chiman; Abdollahpouri, Alireza; Manbari, Zhaleh

    2018-04-01

    Ranking nodes in complex networks have become an important task in many application domains. In a complex network, influential nodes are those that have the most spreading ability. Thus, identifying influential nodes based on their spreading ability is a fundamental task in different applications such as viral marketing. One of the most important centrality measures to ranking nodes is closeness centrality which is efficient but suffers from high computational complexity O(n3) . This paper tries to improve closeness centrality by utilizing the local structure of nodes and presents a new ranking algorithm, called BridgeRank centrality. The proposed method computes local centrality value for each node. For this purpose, at first, communities are detected and the relationship between communities is completely ignored. Then, by applying a centrality in each community, only one best critical node from each community is extracted. Finally, the nodes are ranked based on computing the sum of the shortest path length of nodes to obtained critical nodes. We have also modified the proposed method by weighting the original BridgeRank and selecting several nodes from each community based on the density of that community. Our method can find the best nodes with high spread ability and low time complexity, which make it applicable to large-scale networks. To evaluate the performance of the proposed method, we use the SIR diffusion model. Finally, experiments on real and artificial networks show that our method is able to identify influential nodes so efficiently, and achieves better performance compared to other recent methods.

  10. Research cooperation in the development of laser radar for environmental measurements. Environmental network; Kankyo keisokuyo laser radar no kaihatsu ni kansuru kenkyu kyoryoku. Kankyo network

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    Among the research cooperation in the development of laser radar for environmental measurements with Indonesia between FY 1993 and FY 1996, results of the research and development of the environmental network are summarized. For the environmental information network, the Tokyo NOC is linked as an Internet connection point in Japan with the Jakarta NOC using an international dedicated line with a capacity of 64 Kbps. The Tokyo NOC is linked with domestic environmental information researchers using Internet. Thus, data stored in the data processing system of laser radar can be exchanged, information in both countries can be exchanged using E-mail, and data can be accumulated. For the research cooperation with Indonesia, research of path control and information relay server, research of effective transmission of data on the network, and research of multimedia communication have been conducted. The multimedia communication, distributed processing, and extension of dedicated line network using PPTP have been also conducted. 39 figs., 4 tabs.

  11. Circular resistor networks for electrical impedance tomography with partial boundary measurements

    International Nuclear Information System (INIS)

    Borcea, L; Mamonov, A V; Druskin, V

    2010-01-01

    We introduce an algorithm for the numerical solution of electrical impedance tomography (EIT) in two dimensions, with partial boundary measurements. The algorithm is an extension of the one in Borcea et al (2008 Inverse Problems 24 035013 (31pp)) and Vasquez (2006 PhD Thesis Rice University, Houston, TX, USA) for EIT with full boundary measurements. It is based on resistor networks that arise in finite volume discretizations of the elliptic partial differential equation for the potential on so-called optimal grids that are computed as part of the problem. The grids are adaptively refined near the boundary, where we measure and expect better resolution of the images. They can be used very efficiently in inversion, by defining a reconstruction mapping that is an approximate inverse of the forward map, and acts therefore as a preconditioner in any iterative scheme that solves the inverse problem via optimization. The main result in this paper is the construction of optimal grids for EIT with partial measurements by extremal quasiconformal (Teichmüller) transformations of the optimal grids for EIT with full boundary measurements. We present the algorithm for computing the reconstruction mapping on such grids, and we illustrate its performance with numerical simulations. The results show an interesting trade-off between the resolution of the reconstruction in the domain of the solution and distortions due to artificial anisotropy induced by the distribution of the measurement points on the accessible boundary

  12. Influence of different land surfaces on atmospheric conditions measured by a wireless sensor network

    Science.gov (United States)

    Lengfeld, Katharina; Ament, Felix

    2010-05-01

    Atmospheric conditions close to the surface, like temperature, wind speed and humidity, vary on small scales because of surface heterogeneities. Therefore, the traditional measuring approach of using a single, highly accurate station is of limited representativeness for a larger domain, because it is not able to determine these small scale variabilities. However, both the variability and the domain averages are important information for the development and validation of atmospheric models and soil-vegetation-atmosphere-transfer (SVAT) schemes. Due to progress in microelectronics it is possible to construct networks of comparably cheap meteorological stations with moderate accuracy. Such a network provides data in high spatial and temporal resolution. The EPFL Lausanne developed such a network called SensorScope, consisting of low cost autonomous stations. Each station observes air and surface temperature, humidity, wind direction and speed, incoming solar radiation, precipitations, soil moisture and soil temperature and sends the data via radio communication to a base station. This base station forwards the collected data via GSM/GPRS to a central server. Within the FLUXPAT project in August 2009 we deployed 15 stations as a twin transect near Jülich, Germany. One aim of this first experiment was to test the quality of the low cost sensors by comparing them to more accurate reference measurements. It turned out, that although the network is not highly accurate, the measurements are consistent. Consequently an analysis of the pattern of atmospheric conditions is feasible. For example, we detect a variability of ± 0.5K in the mean temperature at a distance of only 2.3 km. The transect covers different types of vegetation and a small river. Therefore, we analyzed the influence of different land surfaces and the distance to the river on meteorological conditions. On the one hand, some results meet our expectations, e.g. the relative humidity decreases with increasing

  13. Measuring the potential of individual airports for pandemic spread over the world airline network.

    Science.gov (United States)

    Lawyer, Glenn

    2016-02-09

    Massive growth in human mobility has dramatically increased the risk and rate of pandemic spread. Macro-level descriptors of the topology of the World Airline Network (WAN) explains middle and late stage dynamics of pandemic spread mediated by this network, but necessarily regard early stage variation as stochastic. We propose that much of this early stage variation can be explained by appropriately characterizing the local network topology surrounding an outbreak's debut location. Based on a model of the WAN derived from public data, we measure for each airport the expected force of infection (AEF) which a pandemic originating at that airport would generate, assuming an epidemic process which transmits from airport to airport via scheduled commercial flights. We observe, for a subset of world airports, the minimum transmission rate at which a disease becomes pandemically competent at each airport. We also observe, for a larger subset, the time until a pandemically competent outbreak achieves pandemic status given its debut location. Observations are generated using a highly sophisticated metapopulation reaction-diffusion simulator under a disease model known to well replicate the 2009 influenza pandemic. The robustness of the AEF measure to model misspecification is examined by degrading the underlying model WAN. AEF powerfully explains pandemic risk, showing correlation of 0.90 to the transmission level needed to give a disease pandemic competence, and correlation of 0.85 to the delay until an outbreak becomes a pandemic. The AEF is robust to model misspecification. For 97 % of airports, removing 15 % of airports from the model changes their AEF metric by less than 1 %. Appropriately summarizing the size, shape, and diversity of an airport's local neighborhood in the WAN accurately explains much of the macro-level stochasticity in pandemic outcomes.

  14. Evaluation of the online-presence (homepage) of burn units/burn centers in Germany, Austria and Switzerland.

    Science.gov (United States)

    Selig, H F; Lumenta, D B; König, C; Andel, H; Kamolz, L P

    2012-05-01

    A successful online presence is an important key factor in the competition among hospitals today. However, little is known about the internet presence and the quality of websites of burn units on the World Wide Web. The aim was to assess the online presence of hospitals provided by specialized burn units in German speaking countries with a focus on the rate and the performance of actively run websites. A multicenter, observational, cross-sectional study was performed over a period of 1.5 month (October-December 2010). Forty-four burn units were assessed by using a previously generated criteria list. The list included 36 criteria with following topics: "research and teaching"; "patient care"; "clinical emphases", "general information"; "information brokerage". Overall, the websites examined offered a good overview about their different online services with many multimedia-based elements included. All websites consisted of hyperlinks, general multimedia-based elements and information on means of communication with the hospital, respectively. In contrast, the quality of specific information for burn patients was relatively poor. With regard to the need of elderly people, the usability and the layout, the different websites offer a lot of options for future improvements. Burn centers in Germany, Austria and Switzerland already consider the World Wide Web as an important tool for self-promotion and communication. The potential of burn center websites to function as a knowledge base for first aid as well as preventive measurements should be considered and realized in future web site designs. Copyright © 2011 Elsevier Ltd and ISBI. All rights reserved.

  15. A Data-Driven Response Virtual Sensor Technique with Partial Vibration Measurements Using Convolutional Neural Network

    Science.gov (United States)

    Sun, Shan-Bin; He, Yuan-Yuan; Zhou, Si-Da; Yue, Zhen-Jiang

    2017-01-01

    Measurement of dynamic responses plays an important role in structural health monitoring, damage detection and other fields of research. However, in aerospace engineering, the physical sensors are limited in the operational conditions of spacecraft, due to the severe environment in outer space. This paper proposes a virtual sensor model with partial vibration measurements using a convolutional neural network. The transmissibility function is employed as prior knowledge. A four-layer neural network with two convolutional layers, one fully connected layer, and an output layer is proposed as the predicting model. Numerical examples of two different structural dynamic systems demonstrate the performance of the proposed approach. The excellence of the novel technique is further indicated using a simply supported beam experiment comparing to a modal-model-based virtual sensor, which uses modal parameters, such as mode shapes, for estimating the responses of the faulty sensors. The results show that the presented data-driven response virtual sensor technique can predict structural response with high accuracy. PMID:29231868

  16. Using Convolutional Neural Network Filters to Measure Left-Right Mirror Symmetry in Images

    Directory of Open Access Journals (Sweden)

    Anselm Brachmann

    2016-12-01

    Full Text Available We propose a method for measuring symmetry in images by using filter responses from Convolutional Neural Networks (CNNs. The aim of the method is to model human perception of left/right symmetry as closely as possible. Using the Convolutional Neural Network (CNN approach has two main advantages: First, CNN filter responses closely match the responses of neurons in the human visual system; they take information on color, edges and texture into account simultaneously. Second, we can measure higher-order symmetry, which relies not only on color, edges and texture, but also on the shapes and objects that are depicted in images. We validated our algorithm on a dataset of 300 music album covers, which were rated according to their symmetry by 20 human observers, and compared results with those from a previously proposed method. With our method, human perception of symmetry can be predicted with high accuracy. Moreover, we demonstrate that the inclusion of features from higher CNN layers, which encode more abstract image content, increases the performance further. In conclusion, we introduce a model of left/right symmetry that closely models human perception of symmetry in CD album covers.

  17. A Data-Driven Response Virtual Sensor Technique with Partial Vibration Measurements Using Convolutional Neural Network.

    Science.gov (United States)

    Sun, Shan-Bin; He, Yuan-Yuan; Zhou, Si-Da; Yue, Zhen-Jiang

    2017-12-12

    Measurement of dynamic responses plays an important role in structural health monitoring, damage detection and other fields of research. However, in aerospace engineering, the physical sensors are limited in the operational conditions of spacecraft, due to the severe environment in outer space. This paper proposes a virtual sensor model with partial vibration measurements using a convolutional neural network. The transmissibility function is employed as prior knowledge. A four-layer neural network with two convolutional layers, one fully connected layer, and an output layer is proposed as the predicting model. Numerical examples of two different structural dynamic systems demonstrate the performance of the proposed approach. The excellence of the novel technique is further indicated using a simply supported beam experiment comparing to a modal-model-based virtual sensor, which uses modal parameters, such as mode shapes, for estimating the responses of the faulty sensors. The results show that the presented data-driven response virtual sensor technique can predict structural response with high accuracy.

  18. Effective Social Relationship Measurement and Cluster Based Routing in Mobile Opportunistic Networks

    Science.gov (United States)

    Zeng, Feng; Zhao, Nan; Li, Wenjia

    2017-01-01

    In mobile opportunistic networks, the social relationship among nodes has an important impact on data transmission efficiency. Motivated by the strong share ability of “circles of friends” in communication networks such as Facebook, Twitter, Wechat and so on, we take a real-life example to show that social relationships among nodes consist of explicit and implicit parts. The explicit part comes from direct contact among nodes, and the implicit part can be measured through the “circles of friends”. We present the definitions of explicit and implicit social relationships between two nodes, adaptive weights of explicit and implicit parts are given according to the contact feature of nodes, and the distributed mechanism is designed to construct the “circles of friends” of nodes, which is used for the calculation of the implicit part of social relationship between nodes. Based on effective measurement of social relationships, we propose a social-based clustering and routing scheme, in which each node selects the nodes with close social relationships to form a local cluster, and the self-control method is used to keep all cluster members always having close relationships with each other. A cluster-based message forwarding mechanism is designed for opportunistic routing, in which each node only forwards the copy of the message to nodes with the destination node as a member of the local cluster. Simulation results show that the proposed social-based clustering and routing outperforms the other classic routing algorithms. PMID:28498309

  19. Effective Social Relationship Measurement and Cluster Based Routing in Mobile Opportunistic Networks.

    Science.gov (United States)

    Zeng, Feng; Zhao, Nan; Li, Wenjia

    2017-05-12

    In mobile opportunistic networks, the social relationship among nodes has an important impact on data transmission efficiency. Motivated by the strong share ability of "circles of friends" in communication networks such as Facebook, Twitter, Wechat and so on, we take a real-life example to show that social relationships among nodes consist of explicit and implicit parts. The explicit part comes from direct contact among nodes, and the implicit part can be measured through the "circles of friends". We present the definitions of explicit and implicit social relationships between two nodes, adaptive weights of explicit and implicit parts are given according to the contact feature of nodes, and the distributed mechanism is designed to construct the "circles of friends" of nodes, which is used for the calculation of the implicit part of social relationship between nodes. Based on effective measurement of social relationships, we propose a social-based clustering and routing scheme, in which each node selects the nodes with close social relationships to form a local cluster, and the self-control method is used to keep all cluster members always having close relationships with each other. A cluster-based message forwarding mechanism is designed for opportunistic routing, in which each node only forwards the copy of the message to nodes with the destination node as a member of the local cluster. Simulation results show that the proposed social-based clustering and routing outperforms the other classic routing algorithms.

  20. Unraveling chaotic attractors by complex networks and measurements of stock market complexity.

    Science.gov (United States)

    Cao, Hongduo; Li, Ying

    2014-03-01

    We present a novel method for measuring the complexity of a time series by unraveling a chaotic attractor modeled on complex networks. The complexity index R, which can potentially be exploited for prediction, has a similar meaning to the Kolmogorov complexity (calculated from the Lempel-Ziv complexity), and is an appropriate measure of a series' complexity. The proposed method is used to research the complexity of the world's major capital markets. None of these markets are completely random, and they have different degrees of complexity, both over the entire length of their time series and at a level of detail. However, developing markets differ significantly from mature markets. Specifically, the complexity of mature stock markets is stronger and more stable over time, whereas developing markets exhibit relatively low and unstable complexity over certain time periods, implying a stronger long-term price memory process.

  1. Forecasting Financial Extremes: A Network Degree Measure of Super-Exponential Growth.

    Directory of Open Access Journals (Sweden)

    Wanfeng Yan

    Full Text Available Investors in stock market are usually greedy during bull markets and scared during bear markets. The greed or fear spreads across investors quickly. This is known as the herding effect, and often leads to a fast movement of stock prices. During such market regimes, stock prices change at a super-exponential rate and are normally followed by a trend reversal that corrects the previous overreaction. In this paper, we construct an indicator to measure the magnitude of the super-exponential growth of stock prices, by measuring the degree of the price network, generated from the price time series. Twelve major international stock indices have been investigated. Error diagram tests show that this new indicator has strong predictive power for financial extremes, both peaks and troughs. By varying the parameters used to construct the error diagram, we show the predictive power is very robust. The new indicator has a better performance than the LPPL pattern recognition indicator.

  2. Forecasting Financial Extremes: A Network Degree Measure of Super-Exponential Growth.

    Science.gov (United States)

    Yan, Wanfeng; van Tuyll van Serooskerken, Edgar

    2015-01-01

    Investors in stock market are usually greedy during bull markets and scared during bear markets. The greed or fear spreads across investors quickly. This is known as the herding effect, and often leads to a fast movement of stock prices. During such market regimes, stock prices change at a super-exponential rate and are normally followed by a trend reversal that corrects the previous overreaction. In this paper, we construct an indicator to measure the magnitude of the super-exponential growth of stock prices, by measuring the degree of the price network, generated from the price time series. Twelve major international stock indices have been investigated. Error diagram tests show that this new indicator has strong predictive power for financial extremes, both peaks and troughs. By varying the parameters used to construct the error diagram, we show the predictive power is very robust. The new indicator has a better performance than the LPPL pattern recognition indicator.

  3. Neural Networks. Diagnostic and inferential measurements; Reti neurali. Diagnostica e misure inferenziali

    Energy Technology Data Exchange (ETDEWEB)

    Bonavita, N. [Apc Group Leader, Abb Industria, Genua (Italy); Parisini, T. [Milan Politecnico, Milan (Italy). Dipt. di Elettronica e Informazione

    2000-09-01

    In this work, the use of neural approximating networks is described in the context of fault diagnosis of industrial plants with a particular emphasis to the technique of inferential measurements. The proposed methodology is related to the current literature emphasizing advantages and disadvantages of the analytical redundancy concept. The use of neural approximators for the generation of inferential measurement is described in the context of industrial distributed control systems. [Italian] In questo articolo viene descritta l'utilizzazione degli approssimatori neurali in problemi di diagnostica d'impianto con particolare riferimento alla tecnica delle misure inferenziali. Viene fornito un inquadramento della metodologia rispetto alla letteratura attuale mettendo in risalto vantaggi e svantaggi del concetto di ridondanza analitica. L'uso degli approssimatori neurali per la generazione di misure inferenziali e' illustrato in un contesto di sistemi di controllo distribuito di tipo industriale.

  4. Unraveling chaotic attractors by complex networks and measurements of stock market complexity

    International Nuclear Information System (INIS)

    Cao, Hongduo; Li, Ying

    2014-01-01

    We present a novel method for measuring the complexity of a time series by unraveling a chaotic attractor modeled on complex networks. The complexity index R, which can potentially be exploited for prediction, has a similar meaning to the Kolmogorov complexity (calculated from the Lempel–Ziv complexity), and is an appropriate measure of a series' complexity. The proposed method is used to research the complexity of the world's major capital markets. None of these markets are completely random, and they have different degrees of complexity, both over the entire length of their time series and at a level of detail. However, developing markets differ significantly from mature markets. Specifically, the complexity of mature stock markets is stronger and more stable over time, whereas developing markets exhibit relatively low and unstable complexity over certain time periods, implying a stronger long-term price memory process

  5. National network of measurement of radioactivity in the environment - 2014 management report

    International Nuclear Information System (INIS)

    Couvez, Celine; Wyckaert, Laure; Picolo, Jean-Louis; Bicheron, Genevieve

    2015-10-01

    This report aims at presenting evolutions of the regulation of the French National network of measurement of radioactivity in the environment (the RNM), of its organisation, of the operation of its steering committee and various work groups. It also presents evolutions implemented in its information system and Internet web-site which gives public access to radioactivity measurements. After presentation of the RNM objectives and challenges, of the legal context, and a description of the RNM operation, the report presents the involved actors (ASN, IRSN, members of the RNM). The operation of the steering committee and work-groups is assessed. A chapter addresses the information system: description, data harmonisation and new information exchange protocol, technical support by the IRSN to data producers, interaction between the IRSN and system host, application management and third-party applications acceptance. Next parts propose an overview of laboratories certification, and activities related to communication and publications

  6. Evaluation of operational forecast model of aerosol transportation using ceilometer network measurements

    Science.gov (United States)

    Chan, Ka Lok; Wiegner, Matthias; Flentje, Harald; Mattis, Ina; Wagner, Frank; Gasteiger, Josef; Geiß, Alexander

    2017-04-01

    Due to technical improvements of ceilometers in recent years, ceilometer measurements are not only limited to determine cloud base heights but also providing information on the vertical aerosol distribution. Therefore, several national weather services implemented ceilometer networks. These measurements are e.g. valuable for the evaluation of the chemical transport model simulations. In this study, we present comparisons of European Centre for Medium-Range Weather Forecast Integrated Forecast System (ECMWF-IFS) model simulation of aerosol backscatter coefficients with ceilometer network measurements operated by the German weather service (DWD) . Five different types of aerosol are available in the model simulations which include two natural aerosols, sea salt and dust. The other three aerosol types, i.e. sulfate, organic carbon and black carbon, have significant anthropogenic contributions. As the model output provides mass mixing ratios of the above mentioned types of aerosol and the ceilometers measure attenuated backscatter (β∗) provided that calibration took place, it is necessary to determine a common physical quantity for the comparison. We have chosen the aerosol backscatter coefficient (β) for this purpose. The β-profiles are calculated from the mass mixing ratios of the model output assuming the inherent aerosol microphysics properties. It shall be emphasized that in the model calculations, all particles are assumed to be spherical. We have examined the sensitivity of the intercomparison on the hygroscopic growth of particles and on the role of particle shape. Our results show that the hygroscopic growth of particle is crucial (up to a factor of 22) in converting the model output to backscatter coefficient profiles whereas the effect of non-sphericity of dust particles is comparably small (˜44%). Furthermore, the calibration of the ceilometer signals can be an issue. The agreements between modeled and retrieved β-profiles show different

  7. Measuring effectiveness of a university by a parallel network DEA model

    Science.gov (United States)

    Kashim, Rosmaini; Kasim, Maznah Mat; Rahman, Rosshairy Abd

    2017-11-01

    Universities contribute significantly to the development of human capital and socio-economic improvement of a country. Due to that, Malaysian universities carried out various initiatives to improve their performance. Most studies have used the Data Envelopment Analysis (DEA) model to measure efficiency rather than effectiveness, even though, the measurement of effectiveness is important to realize how effective a university in achieving its ultimate goals. A university system has two major functions, namely teaching and research and every function has different resources based on its emphasis. Therefore, a university is actually structured as a parallel production system with its overall effectiveness is the aggregated effectiveness of teaching and research. Hence, this paper is proposing a parallel network DEA model to measure the effectiveness of a university. This model includes internal operations of both teaching and research functions into account in computing the effectiveness of a university system. In literature, the graduate and the number of program offered are defined as the outputs, then, the employed graduates and the numbers of programs accredited from professional bodies are considered as the outcomes for measuring the teaching effectiveness. Amount of grants is regarded as the output of research, while the different quality of publications considered as the outcomes of research. A system is considered effective if only all functions are effective. This model has been tested using a hypothetical set of data consisting of 14 faculties at a public university in Malaysia. The results show that none of the faculties is relatively effective for the overall performance. Three faculties are effective in teaching and two faculties are effective in research. The potential applications of the parallel network DEA model allow the top management of a university to identify weaknesses in any functions in their universities and take rational steps for improvement.

  8. The radioactivity measurement in the Loire catchment basin. Actors, networks, data inventory

    International Nuclear Information System (INIS)

    2008-01-01

    The objective of this report on the Loire watershed was to broaden at all the nuclear installations of the watershed the method of synthesis made for Saint-Laurent-des-Eaux nuclear power plant, by resting on the whole of actors doing the radioactivity measurements in environment. This report shows that these actors are numerous. The measurement plans implemented have for objective to establish the radiological situation of environment, near or not the nuclear facilities, to detect the abnormal increase of radioactivity, to evaluate the exposure of populations to the ambient radioactivity, or to check the conformity of practices (nuclear activities) and products. This assessment enlightens the lack of a real global strategy in the organisation of the radioactivity measurement at the level of the watershed. The inventory of available data for the Loire watershed allowed to show the diversity of measurements realised. The I.R.S.N. is face to a complex situation of data return in the frame of the implementation of an information system of the national network of radioactivity measurement in environment. (N.C.)

  9. The feasibility of measuring social networks among older adults in assisted living and dementia special care units.

    Science.gov (United States)

    Abbott, Katherine M; Bettger, Janet Prvu; Hampton, Keith N; Kohler, Hans-Peter

    2015-03-01

    Studies indicate that social integration has a significant influence on physical and mental health. Older adults experience an increased risk of social isolation as their social networks decline with fewer traditional opportunities to add new social relationships. Deaths of similar aged friends, cognitive and functional impairments, and relocating to a nursing home (NH) or assisted-living (AL) facility contribute to difficulties in maintaining one's social network. Due to the paucity of research examining the social networks of people residing in AL and NH, this study was designed to develop and test the feasibility of using a combination of methodological approaches to capture social network data among older adults living in AL and a dementia special care unit NH. Social network analysis of both egocentric and sociocentric networks was conducted to visualize the social networks of 15 residents of an AL neighborhood and 12 residents of a dementia special care unit NH and to calculate measures network size, centrality, and reciprocity. The combined egocentric and sociocentric method was feasible and provided a robust indicator of resident social networks highlighting individuals who were socially integrated as well as isolated. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  10. Distinct enlargement of network size or measurement speed for serial FBG sensor networks utilizing SIK-DS-CDMA

    Energy Technology Data Exchange (ETDEWEB)

    Abbenseth, S; Lochmann, S I [Hochschule Wismar, Univ. of Technology, Business and Design, Dept. of Electrical Engineering and Informatics, Philipp-Mueller-Strasse, 23952, Wismar (Germany)

    2005-01-01

    Using the spectral selectivity and adjustable reflectivity FBGs are predestined for serial networking. Presently the addressing is realised by time division multiplex (TDM) or wavelength division multiplex (WDM). But these technologies have big disadvantages regarding the effective use of the prevailing resources time and wavelength, respectively. In this paper a new scheme capable of addressing a large number of FBGs in a single serial network is proposed and compared to TDM and WDM. Using all optical sequence inversion keyed (SIK) direct sequence (DS) code division multiplex (CDM) it overcomes the restrictions handling the resources time and wavelength without losing accuracy.

  11. Distinct enlargement of network size or measurement speed for serial FBG sensor networks utilizing SIK-DS-CDMA

    International Nuclear Information System (INIS)

    Abbenseth, S; Lochmann, S I

    2005-01-01

    Using the spectral selectivity and adjustable reflectivity FBGs are predestined for serial networking. Presently the addressing is realised by time division multiplex (TDM) or wavelength division multiplex (WDM). But these technologies have big disadvantages regarding the effective use of the prevailing resources time and wavelength, respectively. In this paper a new scheme capable of addressing a large number of FBGs in a single serial network is proposed and compared to TDM and WDM. Using all optical sequence inversion keyed (SIK) direct sequence (DS) code division multiplex (CDM) it overcomes the restrictions handling the resources time and wavelength without losing accuracy

  12. Physical and Radiological Characterisation of Measuring Sites Within The Croatian Gamma Dose Rate Early Warning Network

    International Nuclear Information System (INIS)

    Cindro, M.; Stepisnik, M.; Pinezic, D.; Sinka, D.; Skanata, D.

    2016-01-01

    The work described in this paper was done within the EU funded project 'Upgrading the systems for the on- and off-line monitoring of radioactivity in the environment in Croatia in regular and emergency situations'. The existing system of early warning in case of nuclear accident in Croatia (SPUNN), managed by the State Office for Radiological and Nuclear Safety, includes 33 stations for measuring ambient gamma dose rate (GDR). The aim of the project was to determine appropriate correction factors that will allow the results from this network to be used not only for timely warning in case of nuclear accident but also in routine environmental monitoring to determine the background radiation. Additionally, in the case of fresh deposition due to radioactive contamination, the corrected values are better suited to be used as an input for support systems for decision making in the case of emergency (such as RODOS), as well as for international data exchange (EURDEP) or automatic interpolation and mapping of radiological data (INTAMAP). The response of the individual probes to natural or accidental radiation mostly depends on the geometry or topography, surrounding buildings, vegetation (trees) and the type of soil beneath the detector. In the case of measuring the dose rate, objects such as buildings act as a shield against gamma radiation and limit the field of vision of the detector. If we want to have representative values that can be compared with other measuring sites, it is clear that we need to define standard conditions that each location has to meet. This is true not only for the probes within the same network, but can also be applied more broadly, at the international level, since data exchange mechanisms for GDR data already exist across Europe. The response of each probe is not determined only by the physical features, it is also important to understand the radiological characteristics of the site. Radiological characterization was performed through

  13. The Community Integration Questionnaire - Revised: Australian normative data and measurement of electronic social networking.

    Science.gov (United States)

    Callaway, Libby; Winkler, Dianne; Tippett, Alice; Herd, Natalie; Migliorini, Christine; Willer, Barry

    2016-06-01

    Consideration of the relationship between meaningful participation, health and wellbeing underpins occupational therapy intervention, and drives measurement of community integration following acquired brain injury (ABI). However, utility of community integration measures has been limited to date by lack of normative data against which to compare outcomes, and none examine the growing use of electronic social networking (ESN) for social participation. This research had four aims: (i) develop and pilot items assessing ESN to add to the Community Integration Questionnaire, producing the Community Integration Questionnaire-Revised (CIQ-R); (ii) examine factor structure of the CIQ-R; (iii) collect Australian CIQ-R normative data; and (iv) assess test-retest reliability of the revised measure. Australia. A convenience sample of adults without ABI (N = 124) was used to develop and pilot ESN items. A representative general population sample of adults without ABI aged 18-64 years (N = 1973) was recruited to gather normative CIQ-R data. Cross-sectional survey. Demographic items and the CIQ-R. The CIQ-R demonstrated acceptable psychometric properties, with minor modification to the original scoring based on the factor analyses provided. Large representative general population CIQ-R normative data have been established, detailing contribution of a range of independent demographic variables to community integration. The addition of electronic social networking items to the CIQ-R offers a contemporary method of assessing community integration following ABI. Normative CIQ-R data enhance the understanding of community integration in the general population, allowing occupational therapists and other clinicians to make more meaningful comparisons between groups. © 2016 Occupational Therapy Australia.

  14. Measure of pore size in micro filtration polymeric membrane using ultrasonic technique and artificial neural networks

    International Nuclear Information System (INIS)

    Lucas, Carla de Souza

    2009-01-01

    This work presents a study of the pore size in micro filtration polymeric membranes, used in the nuclear area for the filtration of radioactive liquid effluent, in the residual water treatment of the petrochemical industry, in the electronic industry for the ultrapure water production for the manufacture of conductors and laundering of microcircuits and in many other processes of separation. Diverse processes for measures of pores sizes in membranes exist, amongst these, electronic microscopy, of bubble point and mercury intrusion porosimetry, however the majority of these uses destructive techniques, of high cost or great time of analysis. The proposal of this work is to measure so great of pore being used ultrasonic technique in the time domain of the frequency and artificial neural networks. A receiving/generator of ultrasonic pulses, a immersion transducer of 25 MHz was used, a tank of immersion and microporous membranes of pores sizes of 0,2 μm, 0,4 μm, 0,6 μm, 8 μm, 10 μm and 12 μm. The ultrasonic signals after to cover the membrane, come back to the transducer (emitting/receiving) bringing information of the interaction of the signal with the membranes. These signals had been used for the training of neural networks, and these had supplied the necessary precision the distinction of the same ones. Soon after, technique with the one of electronic microscopy of sweepings was made the comparison of this. The experiment showed very resulted next to the results gotten with the MEV, what it indicated that the studied technique is ideal for measure of pore size in membranes for being not destructive and of this form to be able to be used also on-line of production. (author)

  15. Application of neural networks to measurement methods based on radiation interactions with matter

    International Nuclear Information System (INIS)

    Pilato, V.

    1999-01-01

    The possibility of improving by neuronal techniques the preparation and interpretation of nuclear measurements was investigated. A general methodology was developed and applied to various problems in this field. Whatever the problem to be treated, to solve it comes to determine the relation which binds the inputs to the outputs. Neural networks based on supervised training, like the multilayer Perceptron, have the capability to calculate any relation between a set of input and output data. On the other hand, the training phase is often a long and delicate operation whose difficulties grow with the size of the network: it is thus interesting to reduce it by introducing knowledge a priori and/or by reducing the number of inputs in order to extract the relevant information. If the correlations between the inputs are linear, the Principal Components Analysis (PCA) and its neuronal equivalents make it possible to obtain by orthogonal projection a reduced number of input components while preserving the maximum of initial information. If the correlations are nonlinear, the Curvilinear Components Analysis (CCA) allows, by a unsupervised training, to carry out a nonlinear projection of the inputs in a space of reduced size. Besides, it is noticed that when the dimension of the input space is equal to the intrinsic dimension of the problem, this last is practically solved by CCA. We propose a general method which consists in characterizing as well as possible the problem by its inputs and then to extract and classify the information contained in those by projection in a space of reduced size. Association between the projected data and the problem outputs is then carried out by a supervised training network. Certain results having to be provided with their associated uncertainty, a statistical method based on the bootstrap algorithm is proposed. Potential applications other that those treated are considered. (author)

  16. Network, anatomical, and non-imaging measures for the prediction of ADHD diagnosis in individual subjects

    Directory of Open Access Journals (Sweden)

    Jason W Bohland

    2012-12-01

    Full Text Available Brain imaging methods have long held promise as diagnostic aids for neuropsychiatric conditions with complex behavioral phenotypes such as Attention-Deficit/Hyperactivity Disorder. This promise has largely been unrealized, at least partly due to the heterogeneity of clinical populations and the small sample size of many studies. A large, multi-center dataset provided by the ADHD-200 Consortium affords new opportunities to test methods for individual diagnosis based on MRI-observable structural brain attributes and functional interactions observable from resting state fMRI. In this study, we systematically calculated a large set of standard and new quantitative markers from individual subject datasets. These features (>12,000 per subject consisted of local anatomical attributes such as cortical thickness and structure volumes and both local and global resting state network measures. Three methods were used to compute graphs representing interdependencies between activations in different brain areas, and a full set of network features was derived from each. Of these, features derived from the inverse of the time series covariance matrix, under an L1-norm regularization penalty, proved most powerful. Anatomical and network feature sets were used individually, and combined with non-imaging phenotypic features from each subject. Machine learning algorithms were used to rank attributes, and performance was assessed under cross-validation and on a separate test set of 168 subjects for a variety of feature set combinations. While non-imaging features gave highest performance in cross-validation, the addition of imaging features in sufficient numbers led to improved generalization to new data. Stratification by gender also proved to be a fruitful strategy to improve classifier performance. We describe the overall approach used, compare the predictive power of different classes of features, and describe the most impactful features in relation to the

  17. Developing convolutional neural networks for measuring climate change opinions from social media data

    Science.gov (United States)

    Mao, H.; Bhaduri, B. L.

    2016-12-01

    Understanding public opinions on climate change is important for policy making. Public opinion, however, is typically measured with national surveys, which are often too expensive and thus being updated at a low frequency. Twitter has become a major platform for people to express their opinions on social and political issues. Our work attempts to understand if Twitter data can provide complimentary insights about climate change perceptions. Since the nature of social media is real-time, this data source can especially help us understand how public opinion changes over time in response to climate events and hazards, which though is very difficult to be captured by manual surveys. We use the Twitter Streaming API to collect tweets that contain keywords, "climate change" or "#climatechange". Traditional machine-learning based opinion mining algorithms require a significant amount of labeled data. Data labeling is notoriously time consuming. To address this problem, we use hashtags (a significant feature used to mark topics of tweets) to annotate tweets automatically. For example, hashtags, #climatedenial and #climatescam, are negative opinion labels, while #actonclimate and #climateaction are positive. Following this method, we can obtain a large amount of training data without human labor. This labeled dataset is used to train a deep convolutional neural network that classifies tweets into positive (i.e. believe in climate change) and negative (i.e. do not believe). Based on the positive/negative tweets obtained, we will further analyze risk perceptions and opinions towards policy support. In addition, we analyze twitter user profiles to understand the demographics of proponents and opponents of climate change. Deep learning techniques, especially convolutional deep neural networks, have achieved much success in computer vision. In this work, we propose a convolutional neural network architecture for understanding opinions within text. This method is compared with

  18. New insights in geodynamics of wider Zagreb area: results of GPS measurements series 2009 on Zagreb Geodynamic Network

    Science.gov (United States)

    Pribičević, Boško; Medak, Damir; ĐApo, Almin

    2010-05-01

    The Geodynamic GPS-Network of the City of Zagreb represents the longest and the most intensive research effort in the field of geodynamics in Croatia. Since the establishment of the Network in 1997, several series of precise GPS measurements have been conducted on specially stabilized points of Geodynamical Network of City of Zagreb with purpose of investigation of tectonic movements and related seismic activity of the wider area of the City of Zagreb. The Network has been densified in 2005 in the most active region of northeastern Mount Medvednica. Since then, several GPS campaigns have been conducted including the last in summer 2009. The paper presents latest results of geodynamic movements of the network points.

  19. Propagation Measurements and Comparison with EM Techniques for In-Cabin Wireless Networks

    Directory of Open Access Journals (Sweden)

    Nektarios Moraitis

    2009-01-01

    Full Text Available This paper presents results of a narrowband measurement campaign conducted inside a Boeing 737–400 aircraft, the objective being the development of a propagation prediction model which can be used in the deployment of in-cabin wireless networks. The measurements were conducted at three different frequency bands: 1.8, 2.1, and 2.45 GHz, representative of several wireless services. Both a simple, empirical, inverse distance power law and a deterministic, site-specific model were investigated. Parameters for the empirical model were extracted from the measurements at different locations inside the cabin: aisle and seats. Additionally, a statistical characterization of the multipath scenario created by the transmitted signal and the various cabin elements is presented. The deterministic model, based on Physical Optics (PO techniques, provides a reasonable match with the empirical results. Finally, measurements and modeling results are provided for the penetration loss into the cabin (or out of the cabin, representative of interference scenarios.

  20. Comparison of Analytical and Measured Performance Results on Network Coding in IEEE 802.11 Ad-Hoc Networks

    DEFF Research Database (Denmark)

    Zhao, Fang; Médard, Muriel; Hundebøll, Martin

    2012-01-01

    CATWOMAN that can run on standard WiFi hardware. We present an analytical model to evaluate the performance of COPE in simple networks, and our results show the excellent predictive quality of this model. By closely examining the performance in two simple topologies, we observe that the coding gain results...

  1. Measuring microscopic evolution processes of complex networks based on empirical data

    International Nuclear Information System (INIS)

    Chi, Liping

    2015-01-01

    Aiming at understanding the microscopic mechanism of complex systems in real world, we perform the measurement that characterizes the evolution properties on two empirical data sets. In the Autonomous Systems Internet data, the network size keeps growing although the system suffers a high rate of node deletion (r = 0.4) and link deletion (q = 0.81). However, the average degree keeps almost unchanged during the whole time range. At each time step the external links attached to a new node are about c = 1.1 and the internal links added between existing nodes are approximately m = 8. For the Scientific Collaboration data, it is a cumulated result of all the authors from 1893 up to the considered year. There is no deletion of nodes and links, r = q = 0. The external and internal links at each time step are c = 1.04 and m = 0, correspondingly. The exponents of degree distribution p(k) ∼ k -γ of these two empirical datasets γ data are in good agreement with that obtained theoretically γ theory . The results indicate that these evolution quantities may provide an insight into capturing the microscopic dynamical processes that govern the network topology. (paper)

  2. Localization in Wireless Sensor Networks: A Survey on Algorithms, Measurement Techniques, Applications and Challenges

    Directory of Open Access Journals (Sweden)

    Anup Kumar Paul

    2017-10-01

    Full Text Available Localization is an important aspect in the field of wireless sensor networks (WSNs that has developed significant research interest among academia and research community. Wireless sensor network is formed by a large number of tiny, low energy, limited processing capability and low-cost sensors that communicate with each other in ad-hoc fashion. The task of determining physical coordinates of sensor nodes in WSNs is known as localization or positioning and is a key factor in today’s communication systems to estimate the place of origin of events. As the requirement of the positioning accuracy for different applications varies, different localization methods are used in different applications and there are several challenges in some special scenarios such as forest fire detection. In this paper, we survey different measurement techniques and strategies for range based and range free localization with an emphasis on the latter. Further, we discuss different localization-based applications, where the estimation of the location information is crucial. Finally, a comprehensive discussion of the challenges such as accuracy, cost, complexity, and scalability are given.

  3. Telecommunications Network Measurements of Online Gambling Behavior in Switzerland: A Feasibility Study.

    Science.gov (United States)

    Bitar, Raoul; Nordt, Carlos; Grosshans, Martin; Herdener, Marcus; Seifritz, Erich; Mutschler, Jochen

    2017-01-01

    Methodological shortcomings of gambling studies relying on self-report or on data sets derived from gambling operators tend to result in biased conclusions. The aim of this study was to analyze online gambling behavior using a novel network database approach. From October 13 to October 26, 2014, telecommunications network data from a major telecommunications provider in Switzerland were analyzed. Netflows between mobile devices and a poker operator were quantified to measure the gambling duration and session number. Time spent gambling during night and working hours was compared between devices with longest (red group), intermediate (orange group), and shortest gambling time (green group). Online gambling behavior differed depending on overall gambling time, F (2, 3,143). Night and working hours gambling was the highest in the red group (53%), compared to the orange (50.1%) and the green groups (41.5%). Post hoc analyses indicated significant differences between the orange and green groups (p social media use, and online pornography. © 2017 S. Karger AG, Basel.

  4. Application of a multilayer perceptron neural network to phytoplankton concentration using marine reflectance measures

    Science.gov (United States)

    Su, Feng-Chun; Ho, Chung-Ru; Kuo, Nan-Jung

    2005-01-01

    The multilayer perceptron (MLP) neural network have been widely used to fit non-linear transfer function and performed well. In this study, we use MLP to estimate chlorophyll-a concentrations from marine reflectance measures. The optical data were assembled from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Bio-optical Algorithm Mini-workshop (SeaBAM). Most bio-optical algorithms use simple ratios of reflectance in blue and green bands or combinations of ratios as parameters for regression analysis. Regression analysis has limitations for nonlinear function. Neural network, however, have been shown better performance for nonlinear problems. The result showed that accuracy of chlorophyll-a concentration using MLP is much higher than that of regression method. Nevertheless, using all of the five bands as input can derive the best performance. The results showed that each band could carry some useful messages for ocean color remote sensing. Only using band ratio (OC2) or band switch (OC4) might lose some available information. By preprocessing reflectance data with the principle component analysis (PCA), MLP could derive much better accuracy than traditional methods. The result showed that the reflectance of all bands should not be ignored for deriving the chlorophyll-a concentration because each band carries different useful ocean color information.

  5. FLOW-BASED NETWORK MEASURES OF BRAIN CONNECTIVITY IN ALZHEIMER'S DISEASE.

    Science.gov (United States)

    Prasad, Gautam; Joshi, Shantanu H; Nir, Talia M; Toga, Arthur W; Thompson, Paul M

    2013-01-01

    We present a new flow-based method for modeling brain structural connectivity. The method uses a modified maximum-flow algorithm that is robust to noise in the diffusion data and guided by biologically viable pathways and structure of the brain. A flow network is first created using a lattice graph by connecting all lattice points (voxel centers) to all their neighbors by edges. Edge weights are based on the orientation distribution function (ODF) value in the direction of the edge. The maximum-flow is computed based on this flow graph using the flow or the capacity between each region of interest (ROI) pair by following the connected tractography fibers projected onto the flow graph edges. Network measures such as global efficiency, transitivity, path length, mean degree, density, modularity, small world, and assortativity are computed from the flow connectivity matrix. We applied our method to diffusion-weighted images (DWIs) from 110 subjects (28 normal elderly, 56 with early and 11 with late mild cognitive impairment, and 15 with AD) and segmented co-registered anatomical MRIs into cortical regions. Experimental results showed better performance compared to the standard fiber-counting methods when distinguishing Alzheimer's disease from normal aging.

  6. Ohio Lake Erie Commission Homepage

    Science.gov (United States)

    management of Lake Erie: including, water quality protection, fisheries management, wetlands restoration over 365 projects since 1993. Projects have focused on an array of issues critical to the effective quality of its waters and ecosystem, and to promote economic development of the region by ensuring the

  7. GPA Homepage -- Present and future

    International Nuclear Information System (INIS)

    Harris, S.C.

    1997-01-01

    The Gas Processors Association has established its presence on the Internet through the development of its Web Page. This site will continue to be developed and expanded so as to strive towards the goal defined in the GPA mission statement of delivering value to the global membership. The current address for the site is http://www.galstar.com/~gpa

  8. An innovative and comprehensive technique to evaluate different measures of medication adherence: The network meta-analysis.

    Science.gov (United States)

    Tonin, Fernanda S; Wiecek, Elyssa; Torres-Robles, Andrea; Pontarolo, Roberto; Benrimoj, Shalom Charlie I; Fernandez-Llimos, Fernando; Garcia-Cardenas, Victoria

    2018-05-19

    Poor medication adherence is associated with adverse health outcomes and higher costs of care. However, inconsistencies in the assessment of adherence are found in the literature. To evaluate the effect of different measures of adherence in the comparative effectiveness of complex interventions to enhance patients' adherence to prescribed medications. A systematic review with network meta-analysis was performed. Electronic searches for relevant pairwise meta-analysis including trials of interventions that aimed to improve medication adherence were performed in PubMed. Data extraction was conducted with eligible trials evaluating short-period adherence follow-up (until 3 months) using any measure of adherence: self-report, pill count, or MEMS (medication event monitoring system). To standardize the results obtained with these different measures, an overall composite measure and an objective composite measure were also calculated. Network meta-analyses for each measure of adherence were built. Rank order and surface under the cumulative ranking curve analyses (SUCRA) were performed. Ninety-one trials were included in the network meta-analyses. The five network meta-analyses demonstrated robustness and reliability. Results obtained for all measures of adherence were similar across them and to both composite measures. For both composite measures, interventions comprising economic + technical components were the best option (90% of probability in SUCRA analysis) with statistical superiority against almost all other interventions and against standard care (odds ratio with 95% credibility interval ranging from 0.09 to 0.25 [0.02, 0.98]). The use of network meta-analysis was reliable to compare different measures of adherence of complex interventions in short-periods follow-up. Analyses with longer follow-up periods are needed to confirm these results. Different measures of adherence produced similar results. The use of composite measures revealed reliable alternatives

  9. Application of Phasor Measurement Units for Protection of Distribution Networks with High Penetration of Photovoltaic Sources

    Science.gov (United States)

    Meskin, Matin

    comprehensive protective system is suggested at the end of the dissertation. The proposed method is based on the application of the phasor measurement unit (PMU) and the differential protection method. All of the current magnitudes and angles are collected by PMU and are sent to the phasor data concentrator (PDC), where a differential protection algorithm is applied to these data. If any fault is detected, the trip will be sent back to the corresponding circuit breakers across the network. Higher selectivity, sensitivity, and faster operation in the differential protection are superior to those of other protection schemes. Differential protection operates as unit protection, which means that it operates only when there is a fault in the protection zone. It does not function for faults occurring out of zone. Therefore, no coordination is required between differential protections across the power system. Moreover, the misoperation of this protective scheme is less likely as compared to other protection methods.

  10. Measuring youth exposure to alcohol marketing on social networking sites: challenges and prospects.

    Science.gov (United States)

    Jernigan, David H; Rushman, Anne E

    2014-02-01

    Youth exposure to alcohol marketing has been linked to increased alcohol consumption and problems. On relatively new and highly interactive social networking sites (SNS) that are popular with youth, tools for measuring youth exposure to alcohol marketing in traditional media are inadequate. We critically review the existing policies of Facebook, Twitter, and YouTube designed to keep branded alcohol content away from underage youth. Looking at brand and user activity on Facebook for the 15 alcohol brands most popular among US youth, we found activity has grown dramatically in the past 3 years, and underage users may be accounting for some of this activity. Surveys of youth and adult participation in alcohol marketing on SNS will be needed to inform debate over these marketing practices.

  11. Investigation of Service Quality of Measurement Reference Points for the Internet Services on Mobile Networks

    Science.gov (United States)

    Lipenbergs, E.; Bobrovs, Vj.; Ivanovs, G.

    2016-10-01

    To ensure that end-users and consumers have access to comprehensive, comparable and user-friendly information regarding the Internet access service quality, it is necessary to implement and regularly renew a set of legislative regulatory acts and to provide monitoring of the quality of Internet access services regarding the current European Regulatory Framework. The actual situation regarding the quality of service monitoring solutions in different European countries depends on national regulatory initiatives and public awareness. The service monitoring solutions are implemented using different measurement methodologies and tools. The paper investigates the practical implementations for developing a harmonising approach to quality monitoring in order to obtain objective information on the quality of Internet access services on mobile networks.

  12. Droplet motion in microfluidic networks: Hydrodynamic interactions and pressure-drop measurements

    Science.gov (United States)

    Sessoms, D. A.; Belloul, M.; Engl, W.; Roche, M.; Courbin, L.; Panizza, P.

    2009-07-01

    We present experimental, numerical, and theoretical studies of droplet flows in hydrodynamic networks. Using both millifluidic and microfluidic devices, we study the partitioning of monodisperse droplets in an asymmetric loop. In both cases, we show that droplet traffic results from the hydrodynamic feedback due to the presence of droplets in the outlet channels. We develop a recently-introduced phenomenological model [W. Engl , Phys. Rev. Lett. 95, 208304 (2005)] and successfully confront its predictions to our experimental results. This approach offers a simple way to measure the excess hydrodynamic resistance of a channel filled with droplets. We discuss the traffic behavior and the variations in the corresponding hydrodynamic resistance length Ld and of the droplet mobility β , as a function of droplet interdistance and confinement for channels having circular or rectangular cross sections.

  13. Slicing, sampling, and distance-dependent effects affect network measures in simulated cortical circuit structures

    Directory of Open Access Journals (Sweden)

    Daniel Carl Miner

    2014-11-01

    Full Text Available The neuroanatomical connectivity of cortical circuits is believed to follow certain rules, the exact origins of which are still poorly understood. In particular, numerous nonrandom features, such as common neighbor clustering, overrepresentation of reciprocal connectivity, and overrepresentation of certain triadic graph motifs have been experimentally observed in cortical slice data. Some of these data, particularly regarding bidirectional connectivity are seemingly contradictory, and the reasons for this are unclear. Here we present a simple static geometric network model with distance-dependent connectivity on a realistic scale that naturally gives rise to certain elements of these observed behaviors, and may provide plausible explanations for some of the conflicting findings. Specifically, investigation of the model shows that experimentally measured nonrandom effects, especially bidirectional connectivity, may depend sensitively on experimental parameters such as slice thickness and sampling area, suggesting potential explanations for the seemingly conflicting experimental results.

  14. Slicing, sampling, and distance-dependent effects affect network measures in simulated cortical circuit structures.

    Science.gov (United States)

    Miner, Daniel C; Triesch, Jochen

    2014-01-01

    The neuroanatomical connectivity of cortical circuits is believed to follow certain rules, the exact origins of which are still poorly understood. In particular, numerous nonrandom features, such as common neighbor clustering, overrepresentation of reciprocal connectivity, and overrepresentation of certain triadic graph motifs have been experimentally observed in cortical slice data. Some of these data, particularly regarding bidirectional connectivity are seemingly contradictory, and the reasons for this are unclear. Here we present a simple static geometric network model with distance-dependent connectivity on a realistic scale that naturally gives rise to certain elements of these observed behaviors, and may provide plausible explanations for some of the conflicting findings. Specifically, investigation of the model shows that experimentally measured nonrandom effects, especially bidirectional connectivity, may depend sensitively on experimental parameters such as slice thickness and sampling area, suggesting potential explanations for the seemingly conflicting experimental results.

  15. Measuring the impact of spatial network layout on community social cohesion: a cross-sectional study.

    Science.gov (United States)

    Cooper, Crispin H V; Fone, David L; Chiaradia, Alain J F

    2014-04-11

    There is now a substantial body of research suggesting that social cohesion, a collective characteristic measured by the levels of trust, reciprocity and formation of strong social bonds within communities, is an important factor in determining health. Of particular interest is the extent to which factors in the built environment facilitate, or impede, the development of social bonds. Severance is a characteristic of physical environments which is hypothesized to inhibit cohesion. In the current study we test a number of characteristics of spatial networks which could be hypothesized to relate either to severance, or directly to community cohesion. Particular focus is given to our most promising variable for further analysis (Convex Hull Maximum Radius 600 m). In the current study we analysed social cohesion as measured at Enumeration District level, aggregated from a survey of 10,892 individuals aged 18 to 74 years in the Caerphilly Health and Social Needs Cohort Study, 2001. In a data mining process we test 16 network variables on multiple scales. The variable showing the most promise is validated in a test on an independent data set. We then conduct a multivariate regression also including Townsend deprivation scores and urban/rural status as predictor variables for social cohesion. We find convex hull maximum radius at a 600 m scale to have a small but highly significant correlation with social cohesion on both data sets. Deprivation has a stronger effect. Splitting the analysis by tertile of deprivation, we find that the effect of severance as measured by this variable is strongest in the most deprived areas. A range of spatial scales are tested, with the strongest effects being observed at scales that match typical walking distances. We conclude that physical connectivity as measured in this paper has a significant effect on social cohesion, and that our measure is unlikely to proxy either deprivation or the urban/rural status of communities. Possible

  16. Radar cross-section measurements of ice particles using vector network analyzer

    Directory of Open Access Journals (Sweden)

    Jinhu Wang

    2016-09-01

    Full Text Available We carried out radar cross-section (RSC measurements of ice particles in a microwave anechoic chamber at Nanjing University of Information Science and Technology. We used microwave similarity theory to enlarge the size of particle from the micrometer to millimeter scale and to reduce the testing frequency from 94 GHz to 10 GHz. The microwave similarity theory was validated using the method of moments for single metal sphere, single dielectric sphere, and spherical and non-spherical dielectric particle swarms. The differences between the retrieved and theoretical results at 94 GHz were 0.016117%, 0.0023029%, 0.027627%, and 0.0046053%, respectively. We proposed a device that can measure the RCS of ice particles in the chamber based on the S21 parameter obtained from vector network analyzer. On the basis of the measured S21 parameter of the calibration material (metal plates and their corresponding theoretical RCS values, the RCS values of a spherical Teflon particle swarm and cuboid candle particle swarm was retrieved at 10 GHz. In this case, the differences between the retrieved and theoretical results were 12.72% and 24.49% for the Teflon particle swarm and cuboid candle swarm, respectively.

  17. A Network-Based Algorithm for Clustering Multivariate Repeated Measures Data

    Science.gov (United States)

    Koslovsky, Matthew; Arellano, John; Schaefer, Caroline; Feiveson, Alan; Young, Millennia; Lee, Stuart

    2017-01-01

    The National Aeronautics and Space Administration (NASA) Astronaut Corps is a unique occupational cohort for which vast amounts of measures data have been collected repeatedly in research or operational studies pre-, in-, and post-flight, as well as during multiple clinical care visits. In exploratory analyses aimed at generating hypotheses regarding physiological changes associated with spaceflight exposure, such as impaired vision, it is of interest to identify anomalies and trends across these expansive datasets. Multivariate clustering algorithms for repeated measures data may help parse the data to identify homogeneous groups of astronauts that have higher risks for a particular physiological change. However, available clustering methods may not be able to accommodate the complex data structures found in NASA data, since the methods often rely on strict model assumptions, require equally-spaced and balanced assessment times, cannot accommodate missing data or differing time scales across variables, and cannot process continuous and discrete data simultaneously. To fill this gap, we propose a network-based, multivariate clustering algorithm for repeated measures data that can be tailored to fit various research settings. Using simulated data, we demonstrate how our method can be used to identify patterns in complex data structures found in practice.

  18. Social Network Analysis: a practical measurement and evaluation of Trust in a classroom environment

    OpenAIRE

    Giandini, Roxana Silvia; Kuz, Antonieta

    2012-01-01

    A social network is formed by a set of actors and the relationships established by them. SNA leads to distinct goals and perspectives of social network analysis and computer science. This paper introduces the study of social networks and their relationship with trust. We study the methods of detection and description of structural properties. This covers the concepts, methods and data analysis techniques of social networks analysis. After that, we introduce the concept of trust and its relati...

  19. Wireless Distributed Environmental Sensor Networks for Air Pollution Measurement-The Promise and the Current Reality.

    Science.gov (United States)

    Broday, David M

    2017-10-02

    The evaluation of the effects of air pollution on public health and human-wellbeing requires reliable data. Standard air quality monitoring stations provide accurate measurements of airborne pollutant levels, but, due to their sparse distribution, they cannot capture accurately the spatial variability of air pollutant concentrations within cities. Dedicated in-depth field campaigns have dense spatial coverage of the measurements but are held for relatively short time periods. Hence, their representativeness is limited. Moreover, the oftentimes integrated measurements represent time-averaged records. Recent advances in communication and sensor technologies enable the deployment of dense grids of Wireless Distributed Environmental Sensor Networks for air quality monitoring, yet their capability to capture urban-scale spatiotemporal pollutant patterns has not been thoroughly examined to date. Here, we summarize our studies on the practicalities of using data streams from sensor nodes for air quality measurement and the required methods to tune the results to different stakeholders and applications. We summarize the results from eight cities across Europe, five sensor technologies-three stationary (with one tested also while moving) and two personal sensor platforms, and eight ambient pollutants. Overall, few sensors showed an exceptional and consistent performance, which can shed light on the fine spatiotemporal urban variability of pollutant concentrations. Stationary sensor nodes were more reliable than personal nodes. In general, the sensor measurements tend to suffer from the interference of various environmental factors and require frequent calibrations. This calls for the development of suitable field calibration procedures, and several such in situ field calibrations are presented.

  20. Internal measuring models in trained neural networks for parameter estimation from images

    NARCIS (Netherlands)

    Feng, Tian-Jin; Feng, T.J.; Houkes, Z.; Korsten, Maarten J.; Spreeuwers, Lieuwe Jan

    1992-01-01

    The internal representations of 'learned' knowledge in neural networks are still poorly understood, even for backpropagation networks. The paper discusses a possible interpretation of learned knowledge of a network trained for parameter estimation from images. The outputs of the hidden layer are the

  1. Radio frequency sensing measurements and methods for location classification in wireless networks

    Science.gov (United States)

    Maas, Dustin C.

    The wireless radio channel is typically thought of as a means to move information from transmitter to receiver, but the radio channel can also be used to detect changes in the environment of the radio link. This dissertation is focused on the measurements we can make at the physical layer of wireless networks, and how we can use those measurements to obtain information about the locations of transceivers and people. The first contribution of this work is the development and testing of an open source, 802.11b sounder and receiver, which is capable of decoding packets and using them to estimate the channel impulse response (CIR) of a radio link at a fraction of the cost of traditional channel sounders. This receiver improves on previous implementations by performing optimized matched filtering on the field-programmable gate array (FPGA) of the Universal Software Radio Peripheral (USRP), allowing it to operate at full bandwidth. The second contribution of this work is an extensive experimental evaluation of a technology called location distinction, i.e., the ability to identify changes in radio transceiver position, via CIR measurements. Previous location distinction work has focused on single-input single-output (SISO) radio links. We extend this work to the context of multiple-input multiple-output (MIMO) radio links, and study system design trade-offs which affect the performance of MIMO location distinction. The third contribution of this work introduces the "exploiting radio windows" (ERW) attack, in which an attacker outside of a building surreptitiously uses the transmissions of an otherwise secure wireless network inside of the building to infer location information about people inside the building. This is possible because of the relative transparency of external walls to radio transmissions. The final contribution of this dissertation is a feasibility study for building a rapidly deployable radio tomographic (RTI) imaging system for special operations forces

  2. Atrophy in distinct corticolimbic networks in frontotemporal dementia relates to social impairments measured using the Social Impairment Rating Scale

    Science.gov (United States)

    Bickart, Kevin C; Brickhouse, Michael; Negreira, Alyson; Sapolsky, Daisy

    2015-01-01

    Patients with frontotemporal dementia (FTD) often exhibit prominent, early and progressive impairments in social behaviour. We developed the Social Impairment Rating Scale (SIRS), rated by a clinician after a structured interview, which grades the types and severity of social behavioural symptoms in seven domains. In 20 FTD patients, we used the SIRS to study the anatomic basis of social impairments. In support of hypotheses generated from a prior study of healthy adults, we found that the relative magnitude of brain atrophy in three partially dissociable corticolimbic networks anchored in the amygdala predicted the severity of distinct social impairments measured using the SIRS. Patients with the greatest atrophy in a mesolimbic, reward-related (affiliation) network exhibited the most severe socioemotional detachment, whereas patients with the greatest atrophy in an interoceptive, pain-related (aversion) network exhibited the most severe lack of social apprehension. Patients with the greatest atrophy in a perceptual network exhibited the most severe lack of awareness or understanding of others’ social and emotional behaviour. Our findings underscore observations that FTD is associated with heterogeneous social symptoms that can be understood in a refined manner by measuring impairments in component processes subserved by dissociable neural networks. Furthermore, these findings support the validity of the SIRS as an instrument to measure the social symptoms of patients with FTD. Ultimately, we hope it will be useful as a longitudinal outcome measure in natural history studies and in clinical trials of putative interventions to improve social functioning. PMID:24133285

  3. The use of EORTC measures in daily clinical practice—A synopsis of a newly developed manual

    DEFF Research Database (Denmark)

    Wintner, Lisa M; Sztankay, Monika; Aaronson, Neil

    2016-01-01

    possible and to encourage readers and end-users of EORTC measures to contribute to further needed high-quality research. The manual will be accessible on the EORTC Quality of Life Group website's homepage and will be periodically updated to take into account any new knowledge due to medical, technical...

  4. Measuring the consequences of wildfires in a Bayesian network with vulnerability and exposure indicators

    Science.gov (United States)

    Papakosta, Panagiota; Botzler, Sebastian; Krug, Kai; Straub, Daniel

    2013-04-01

    areas and rare species is also included. Presence of cultural heritage sites, power stations and power line network influence social exposure. The conceptual framework is demonstrated with a Bayesian Network (BN). The BN model incorporates empirical observation, physical models and expert knowledge; it can also explicitly account for uncertainty in the indicators. The proposed model is applied to the island of Cyprus. Maps support the demonstration of results. [1] Keeley, J.E.; Bond, W.J.; Bradstock, R.A.; Pausas, J.G.; Rundel, P.W. (2012): Fire in Mediterranean ecosystems: ecology, evolution and management. Cambridge University Press, New York, USA. [2] UN/ISDR (International Strategy for Disaster Reduction (2004): Living with Risk: A Global Review of Disaster Reduction Initiatives, Geneva, UN Publications. [3] Birkmann, J. (2006): Measuring vulnerability to natural hazards: towards disaster resilient societies. United Nations University Press, Tokyo, Japan.

  5. Detection capability of the IMS seismic network based on ambient seismic noise measurements

    Science.gov (United States)

    Gaebler, Peter J.; Ceranna, Lars

    2016-04-01

    All nuclear explosions - on the Earth's surface, underground, underwater or in the atmosphere - are banned by the Comprehensive Nuclear-Test-Ban Treaty (CTBT). As part of this treaty, a verification regime was put into place to detect, locate and characterize nuclear explosion testings at any time, by anyone and everywhere on the Earth. The International Monitoring System (IMS) plays a key role in the verification regime of the CTBT. Out of the different monitoring techniques used in the IMS, the seismic waveform approach is the most effective technology for monitoring nuclear underground testing and to identify and characterize potential nuclear events. This study introduces a method of seismic threshold monitoring to assess an upper magnitude limit of a potential seismic event in a certain given geographical region. The method is based on ambient seismic background noise measurements at the individual IMS seismic stations as well as on global distance correction terms for body wave magnitudes, which are calculated using the seismic reflectivity method. From our investigations we conclude that a global detection threshold of around mb 4.0 can be achieved using only stations from the primary seismic network, a clear latitudinal dependence for the detection threshold can be observed between northern and southern hemisphere. Including the seismic stations being part of the auxiliary seismic IMS network results in a slight improvement of global detection capability. However, including wave arrivals from distances greater than 120 degrees, mainly PKP-wave arrivals, leads to a significant improvement in average global detection capability. In special this leads to an improvement of the detection threshold on the southern hemisphere. We further investigate the dependence of the detection capability on spatial (latitude and longitude) and temporal (time) parameters, as well as on parameters such as source type and percentage of operational IMS stations.

  6. Network meta-analysis of multiple outcome measures accounting for borrowing of information across outcomes.

    Science.gov (United States)

    Achana, Felix A; Cooper, Nicola J; Bujkiewicz, Sylwia; Hubbard, Stephanie J; Kendrick, Denise; Jones, David R; Sutton, Alex J

    2014-07-21

    Network meta-analysis (NMA) enables simultaneous comparison of multiple treatments while preserving randomisation. When summarising evidence to inform an economic evaluation, it is important that the analysis accurately reflects the dependency structure within the data, as correlations between outcomes may have implication for estimating the net benefit associated with treatment. A multivariate NMA offers a framework for evaluating multiple treatments across multiple outcome measures while accounting for the correlation structure between outcomes. The standard NMA model is extended to multiple outcome settings in two stages. In the first stage, information is borrowed across outcomes as well across studies through modelling the within-study and between-study correlation structure. In the second stage, we make use of the additional assumption that intervention effects are exchangeable between outcomes to predict effect estimates for all outcomes, including effect estimates on outcomes where evidence is either sparse or the treatment had not been considered by any one of the studies included in the analysis. We apply the methods to binary outcome data from a systematic review evaluating the effectiveness of nine home safety interventions on uptake of three poisoning prevention practices (safe storage of medicines, safe storage of other household products, and possession of poison centre control telephone number) in households with children. Analyses are conducted in WinBUGS using Markov Chain Monte Carlo (MCMC) simulations. Univariate and the first stage multivariate models produced broadly similar point estimates of intervention effects but the uncertainty around the multivariate estimates varied depending on the prior distribution specified for the between-study covariance structure. The second stage multivariate analyses produced more precise effect estimates while enabling intervention effects to be predicted for all outcomes, including intervention effects on

  7. An ultra-low power wireless sensor network for bicycle torque performance measurements.

    Science.gov (United States)

    Gharghan, Sadik K; Nordin, Rosdiadee; Ismail, Mahamod

    2015-05-21

    In this paper, we propose an energy-efficient transmission technique known as the sleep/wake algorithm for a bicycle torque sensor node. This paper aims to highlight the trade-off between energy efficiency and the communication range between the cyclist and coach. Two experiments were conducted. The first experiment utilised the Zigbee protocol (XBee S2), and the second experiment used the Advanced and Adaptive Network Technology (ANT) protocol based on the Nordic nRF24L01 radio transceiver chip. The current consumption of ANT was measured, simulated and compared with a torque sensor node that uses the XBee S2 protocol. In addition, an analytical model was derived to correlate the sensor node average current consumption with a crank arm cadence. The sensor node achieved 98% power savings for ANT relative to ZigBee when they were compared alone, and the power savings amounted to 30% when all components of the sensor node are considered. The achievable communication range was 65 and 50 m for ZigBee and ANT, respectively, during measurement on an outdoor cycling track (i.e., velodrome). The conclusions indicate that the ANT protocol is more suitable for use in a torque sensor node when power consumption is a crucial demand, whereas the ZigBee protocol is more convenient in ensuring data communication between cyclist and coach.

  8. Pipeline Bending Strain Measurement and Compensation Technology Based on Wavelet Neural Network

    Directory of Open Access Journals (Sweden)

    Rui Li

    2016-01-01

    Full Text Available The bending strain of long distance oil and gas pipelines may lead to instability of the pipeline and failure of materials, which seriously deteriorates the transportation security of oil and gas. To locate the position of the bending strain for maintenance, an Inertial Measurement Unit (IMU is usually adopted in a Pipeline Inspection Gauge (PIG. The attitude data of the IMU is usually acquired to calculate the bending strain in the pipe. However, because of the vibrations in the pipeline and other system noises, the resulting bending strain calculations may be incorrect. To improve the measurement precision, a method, based on wavelet neural network, was proposed. To test the proposed method experimentally, a PIG with the proposed method is used to detect a straight pipeline. It can be obtained that the proposed method has a better repeatability and convergence than the original method. Furthermore, the new method is more accurate than the original method and the accuracy of bending strain is raised by about 23% compared to original method. This paper provides a novel method for precisely inspecting bending strain of long distance oil and gas pipelines and lays a foundation for improving the precision of inspection of bending strain of long distance oil and gas pipelines.

  9. Influence of a multidimensional measure of attitudes on motives to use social networking sites.

    Science.gov (United States)

    Krishnan, Archana; Hunt, Daniel Scot

    2015-03-01

    Positive attitudes toward a new communication technology tend to be a significant motivator in subsequent adoption and use. The recent spurt in the adoption of social media tools such as social networking sites (SNSs) demands the examination of attitudinal variables on motives to use these Web sites. This study explicated a multidimensional measure of attitudes toward SNSs and tested a theoretical model to examine the effect of attitudes on motives to use SNSs and SNS activity. Participants (N=674) completed a cross-sectional survey consisting of measures of attitudes toward SNSs, motives of SNS use, and level of activity. Results showed support for a revised model in which attitudinal variables-ease of use, self-disclosure, and social connection-strongly predicted motives of SNS use such as passing time, information/entertainment, social conformity, and, most importantly, socialization. The motive of using SNSs as a social tool superseded the direct effect of other motives on SNS activity, suggesting that users' primary activity on SNSs was for socialization and for relational development and maintenance.

  10. Propagation based phase retrieval of simulated intensity measurements using artificial neural networks

    Science.gov (United States)

    Kemp, Z. D. C.

    2018-04-01

    Determining the phase of a wave from intensity measurements has many applications in fields such as electron microscopy, visible light optics, and medical imaging. Propagation based phase retrieval, where the phase is obtained from defocused images, has shown significant promise. There are, however, limitations in the accuracy of the retrieved phase arising from such methods. Sources of error include shot noise, image misalignment, and diffraction artifacts. We explore the use of artificial neural networks (ANNs) to improve the accuracy of propagation based phase retrieval algorithms applied to simulated intensity measurements. We employ a phase retrieval algorithm based on the transport-of-intensity equation to obtain the phase from simulated micrographs of procedurally generated specimens. We then train an ANN with pairs of retrieved and exact phases, and use the trained ANN to process a test set of retrieved phase maps. The total error in the phase is significantly reduced using this method. We also discuss a variety of potential extensions to this work.

  11. Performance measurement of the after-sales service network: Evidence from the automotive industry

    Directory of Open Access Journals (Sweden)

    Shahnoush Shahrouzi Fard

    2015-10-01

    Full Text Available This paper presents an empirical investigation to determine important factors influencing on customer satisfaction in after-sales service network of automotive industry. The study designs two questionnaires, one for measuring the quality of after-sales services and the other for measuring customers’ satisfaction. The study selects a sample of 265 randomly selected customers out of 850 people who received the services from an automotive firm in Iran. Cronbach alpha has calculated as 0.82, which is well above the minimum desirable level. Using Spearman correlation the study has detected a positive and meaningful relationship between services and customer satisfaction (r=0.48, Sig. =0.01, a positive relationship between being responsiveness and customer satisfaction (r=0.51, Sig. =0.01 and finally a positive relationship between speed of operation customer satisfaction (r=0.45, Sig. = 0.01. Moreover, there was a positive and meaningful relationship between cost of services and customer satisfaction (r=0.68, Sig. = 0.01 and a positive relationship between quality of services of after-sales services and customer satisfaction (r = 0.61, Sig. =0.01.

  12. An Ultra-Low Power Wireless Sensor Network for Bicycle Torque Performance Measurements

    Science.gov (United States)

    Gharghan, Sadik K.; Nordin, Rosdiadee; Ismail, Mahamod

    2015-01-01

    In this paper, we propose an energy-efficient transmission technique known as the sleep/wake algorithm for a bicycle torque sensor node. This paper aims to highlight the trade-off between energy efficiency and the communication range between the cyclist and coach. Two experiments were conducted. The first experiment utilised the Zigbee protocol (XBee S2), and the second experiment used the Advanced and Adaptive Network Technology (ANT) protocol based on the Nordic nRF24L01 radio transceiver chip. The current consumption of ANT was measured, simulated and compared with a torque sensor node that uses the XBee S2 protocol. In addition, an analytical model was derived to correlate the sensor node average current consumption with a crank arm cadence. The sensor node achieved 98% power savings for ANT relative to ZigBee when they were compared alone, and the power savings amounted to 30% when all components of the sensor node are considered. The achievable communication range was 65 and 50 m for ZigBee and ANT, respectively, during measurement on an outdoor cycling track (i.e., velodrome). The conclusions indicate that the ANT protocol is more suitable for use in a torque sensor node when power consumption is a crucial demand, whereas the ZigBee protocol is more convenient in ensuring data communication between cyclist and coach. PMID:26007728

  13. Measurement and Evaluation of Finger Tapping Movements Using Log-linearized Gaussian Mixture Networks

    Directory of Open Access Journals (Sweden)

    Masaru Yokoe

    2009-03-01

    Full Text Available This paper proposes a method to quantitatively measure and evaluate finger tapping movements for the assessment of motor function using log-linearized Gaussian mixture networks (LLGMNs. First, finger tapping movements are measured using magnetic sensors, and eleven indices are computed for evaluation. After standardizing these indices based on those of normal subjects, they are input to LLGMNs to assess motor function. Then, motor ability is probabilistically discriminated to determine whether it is normal or not using a classifier combined with the output of multiple LLGMNs based on bagging and entropy. This paper reports on evaluation and discrimination experiments performed on finger tapping movements in 33 Parkinson’s disease (PD patients and 32 normal elderly subjects. The results showed that the patients could be classified correctly in terms of their impairment status with a high degree of accuracy (average rate: 93:1 § 3:69% using 12 LLGMNs, which was about 5% higher than the results obtained using a single LLGMN.

  14. WAVELET ANALYSIS AND NEURAL NETWORK CLASSIFIERS TO DETECT MID-SAGITTAL SECTIONS FOR NUCHAL TRANSLUCENCY MEASUREMENT

    Directory of Open Access Journals (Sweden)

    Giuseppa Sciortino

    2016-04-01

    Full Text Available We propose a methodology to support the physician in the automatic identification of mid-sagittal sections of the fetus in ultrasound videos acquired during the first trimester of pregnancy. A good mid-sagittal section is a key requirement to make the correct measurement of nuchal translucency which is one of the main marker for screening of chromosomal defects such as trisomy 13, 18 and 21. NT measurement is beyond the scope of this article. The proposed methodology is mainly based on wavelet analysis and neural network classifiers to detect the jawbone and on radial symmetry analysis to detect the choroid plexus. Those steps allow to identify the frames which represent correct mid-sagittal sections to be processed. The performance of the proposed methodology was analyzed on 3000 random frames uniformly extracted from 10 real clinical ultrasound videos. With respect to a ground-truth provided by an expert physician, we obtained a true positive, a true negative and a balanced accuracy equal to 87.26%, 94.98% and 91.12% respectively.

  15. Measurements by a Vector Network Analyzer at 325 to 508 GHz

    Science.gov (United States)

    Fung, King Man; Samoska, Lorene; Chattopadhyay, Goutam; Gaier, Todd; Kangaslahti, Pekka; Pukala, David; Lau, Yuenie; Oleson, Charles; Denning, Anthony

    2008-01-01

    Recent experiments were performed in which return loss and insertion loss of waveguide test assemblies in the frequency range from 325 to 508 GHz were measured by use of a swept-frequency two-port vector network analyzer (VNA) test set. The experiments were part of a continuing effort to develop means of characterizing passive and active electronic components and systems operating at ever increasing frequencies. The waveguide test assemblies comprised WR-2.2 end sections collinear with WR-3.3 middle sections. The test set, assembled from commercially available components, included a 50-GHz VNA scattering- parameter test set and external signal synthesizers, augmented with recently developed frequency extenders, and further augmented with attenuators and amplifiers as needed to adjust radiofrequency and intermediate-frequency power levels between the aforementioned components. The tests included line-reflect-line calibration procedures, using WR-2.2 waveguide shims as the "line" standards and waveguide flange short circuits as the "reflect" standards. Calibrated dynamic ranges somewhat greater than about 20 dB for return loss and 35 dB for insertion loss were achieved. The measurement data of the test assemblies were found to substantially agree with results of computational simulations.

  16. Pavement type and wear condition classification from tire cavity acoustic measurements with artificial neural networks.

    Science.gov (United States)

    Masino, Johannes; Foitzik, Michael-Jan; Frey, Michael; Gauterin, Frank

    2017-06-01

    Tire road noise is the major contributor to traffic noise, which leads to general annoyance, speech interference, and sleep disturbances. Standardized methods to measure tire road noise are expensive, sophisticated to use, and they cannot be applied comprehensively. This paper presents a method to automatically classify different types of pavement and the wear condition to identify noisy road surfaces. The methods are based on spectra of time series data of the tire cavity sound, acquired under normal vehicle operation. The classifier, an artificial neural network, correctly predicts three pavement types, whereas there are few bidirectional mis-classifications for two pavements, which have similar physical characteristics. The performance measures of the classifier to predict a new or worn out condition are over 94.6%. One could create a digital map with the output of the presented method. On the basis of these digital maps, road segments with a strong impact on tire road noise could be automatically identified. Furthermore, the method can estimate the road macro-texture, which has an impact on the tire road friction especially on wet conditions. Overall, this digital map would have a great benefit for civil engineering departments, road infrastructure operators, and for advanced driver assistance systems.

  17. An Ultra-Low Power Wireless Sensor Network for Bicycle Torque Performance Measurements

    Directory of Open Access Journals (Sweden)

    Sadik K. Gharghan

    2015-05-01

    Full Text Available In this paper, we propose an energy-efficient transmission technique known as the sleep/wake algorithm for a bicycle torque sensor node. This paper aims to highlight the trade-off between energy efficiency and the communication range between the cyclist and coach. Two experiments were conducted. The first experiment utilised the Zigbee protocol (XBee S2, and the second experiment used the Advanced and Adaptive Network Technology (ANT protocol based on the Nordic nRF24L01 radio transceiver chip. The current consumption of ANT was measured, simulated and compared with a torque sensor node that uses the XBee S2 protocol. In addition, an analytical model was derived to correlate the sensor node average current consumption with a crank arm cadence. The sensor node achieved 98% power savings for ANT relative to ZigBee when they were compared alone, and the power savings amounted to 30% when all components of the sensor node are considered. The achievable communication range was 65 and 50 m for ZigBee and ANT, respectively, during measurement on an outdoor cycling track (i.e., velodrome. The conclusions indicate that the ANT protocol is more suitable for use in a torque sensor node when power consumption is a crucial demand, whereas the ZigBee protocol is more convenient in ensuring data communication between cyclist and coach.

  18. Questions of trust in health research on social capital: what aspects of personal network social capital do they measure?

    Science.gov (United States)

    Carpiano, Richard M; Fitterer, Lisa M

    2014-09-01

    Health research on personal social capital has often utilized measures of respondents' perceived trust of others as either a proxy for one's social capital in the absence of more focused measures or as a subjective component of social capital. Little empirical work has evaluated the validity of such practices. We test the construct validity of two trust measures used commonly in health research on social capital-generalized trust and trust of neighbors-with respect to measures of people's general network-, organization-, family-, friend-, and neighborhood-based social capital and the extent to which these two trust measures are associated with self-rated general health and mental health when social capital measures are included in the same models. Analyses of 2008 Canadian General Social Survey data (response rate 57.3%) indicate that generalized trust and trust of neighbors are both positively-yet modestly-associated with measures of several domains of network-based social capital. Both trust measures are positively associated with general and mental health, but these associations remain robust after adjusting for social capital measures. Our findings suggest that (a) trust is conceptually distinct from social capital, (b) trust measures are inadequate proxies for actual personal social networks, and (c) trust measures may only be capturing psychological aspects relevant to-but not indicative of-social capital. Though links between perceived trust and health deserve study, health research on social capital needs to utilize measures of respondents' actual social networks and their inherent resources. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Validation Techniques of network harmonic models based on switching of a series linear component and measuring resultant harmonic increments

    DEFF Research Database (Denmark)

    Wiechowski, Wojciech Tomasz; Lykkegaard, Jan; Bak, Claus Leth

    2007-01-01

    In this paper two methods of validation of transmission network harmonic models are introduced. The methods were developed as a result of the work presented in [1]. The first method allows calculating the transfer harmonic impedance between two nodes of a network. Switching a linear, series network......, as for example a transmission line. Both methods require that harmonic measurements performed at two ends of the disconnected element are precisely synchronized....... are used for calculation of the transfer harmonic impedance between the nodes. The determined transfer harmonic impedance can be used to validate a computer model of the network. The second method is an extension of the fist one. It allows switching a series element that contains a shunt branch...

  20. The impact of ambient dose rate measuring network and precipitation radar system for detection of environmental radioactivity released by accident

    International Nuclear Information System (INIS)

    Bleher, M; Stoehlker, U.

    2003-01-01

    For the surveillance of environmental radioactivity, the German measuring network of BfS consists of more than 2000 stations where the ambient gamma dose rate is continuously measured. This network is a helpful tool to detect and localise enhanced environmental contamination from artificial radionuclides. The threshold for early warning is so low, that already an additional dose rate contribution of 0,07 μGy/h is detectable. However, this threshold is frequently exceeded due to precipitation events caused by washout of natural activity in air. Therefore, the precipitation radar system of the German Weather Service provides valuable information on the problem, whether the increase of the ambient dose rate is due to natural or man-made events. In case of an accidental release, the data of this radar system show small area precipitation events and potential local hot spots not detected by the measuring network. For the phase of cloud passage, the ambient dose rate measuring network provides a reliable database for the evaluation of the current situation and its further development. It is possible to compare measured data for dose rate with derived intervention levels for countermeasures like ''sheltering''. Thus, critical regions can be identified and it is possible to verify implemented countermeasures. During and after this phase of cloud passage the measured data of the monitoring network help to adapt the results of the national decision support systems PARK and RODOS. Therefore, it is necessary to derive the actual additional contribution to the ambient dose rate. Map representations of measured dose rate are rapidly available and helpful to optimise measurement strategies of mobile systems and collection strategies for samples of agricultural products. (orig.)

  1. Mental health and social networks in early adolescence: a dynamic study of objectively-measured social interaction behaviors.

    Science.gov (United States)

    Pachucki, Mark C; Ozer, Emily J; Barrat, Alain; Cattuto, Ciro

    2015-01-01

    How are social interaction dynamics associated with mental health during early stages of adolescence? The goal of this study is to objectively measure social interactions and evaluate the roles that multiple aspects of the social environment--such as physical activity and food choice--may jointly play in shaping the structure of children's relationships and their mental health. The data in this study are drawn from a longitudinal network-behavior study conducted in 2012 at a private K-8 school in an urban setting in California. We recruited a highly complete network sample of sixth-graders (n = 40, 91% of grade, mean age = 12.3), and examined how two measures of distressed mental health (self-esteem and depressive symptoms) are positionally distributed in an early adolescent interaction network. We ascertained how distressed mental health shapes the structure of relationships over a three-month period, adjusting for relevant dimensions of the social environment. Cross-sectional analyses of interaction networks revealed that self-esteem and depressive symptoms are differentially stratified by gender. Specifically, girls with more depressive symptoms have interactions consistent with social inhibition, while boys' interactions suggest robustness to depressive symptoms. Girls higher in self-esteem tended towards greater sociability. Longitudinal network behavior models indicate that gender similarity and perceived popularity are influential in the formation of social ties. Greater school connectedness predicts the development of self-esteem, though social ties contribute to more self-esteem improvement among students who identify as European-American. Cross-sectional evidence shows associations between distressed mental health and students' network peers. However, there is no evidence that connected students' mental health status becomes more similar in their over time because of their network interactions. These findings suggest that mental health during early

  2. Validation of Leaf Area Index measurements based on the Wireless Sensor Network platform

    Science.gov (United States)

    Song, Q.; Li, X.; Liu, Q.

    2017-12-01

    The leaf area index (LAI) is one of the important parameters for estimating plant canopy function, which has significance for agricultural analysis such as crop yield estimation and disease evaluation. The quick and accurate access to acquire crop LAI is particularly vital. In the study, LAI measurement of corn crops is mainly through three kinds of methods: the leaf length and width method (LAILLW), the instruments indirect measurement method (LAII) and the leaf area index sensor method(LAIS). Among them, LAI value obtained from LAILLW can be regarded as approximate true value. LAI-2200,the current widespread LAI canopy analyzer,is used in LAII. LAIS based on wireless sensor network can realize the automatic acquisition of crop images,simplifying the data collection work,while the other two methods need person to carry out field measurements.Through the comparison of LAIS and other two methods, the validity and reliability of LAIS observation system is verified. It is found that LAI trend changes are similar in three methods, and the rate of change of LAI has an increase with time in the first two months of corn growth when LAIS costs less manpower, energy and time. LAI derived from LAIS is more accurate than LAII in the early growth stage,due to the small blade especially under the strong light. Besides, LAI processed from a false color image with near infrared information is much closer to the true value than true color picture after the corn growth period up to one and half months.

  3. Representativeness of regional and global mass-balance measurement networks (Invited)

    Science.gov (United States)

    Cogley, J. G.; Moholdt, G.; Gardner, A. S.

    2013-12-01

    We showed in a recent publication that regional estimates of glacier mass budgets, obtained by interpolation from in-situ measurements, were markedly more negative than corresponding estimates by satellite gravimetry (GRACE) and satellite altimetry (ICESat) during 2003-2009. Examining the ICESat data in more detail, we found that in-situ records tend to be located in areas where glaciers are thinning more rapidly than as observed in their regional surroundings. Because neither GRACE nor ICESat can provide information for times before 2002-2003, and may not operate without interruption in the future, we explore possible explanations of and remedies for the identified bias in the in-situ network. Sparse spatial sampling, coupled with previously undetected spatial variability of mass balance at scales between the 10-km in-situ scale and the 350-km gravimetric scale, appears to be the leading explanation. Satisfactory remedies are not obvious. Selecting glaciers for in-situ measurement that are more representative will yield only incremental improvements. There appears to be no alternative to mass-balance modelling as a versatile tool for estimation of regional mass balance. However the meteorological data for forcing the surface components of glacier models have coarser resolution than is desirable and are themselves uncertain, especially in the remote regions where much of the glacier ice is found. Measurements of frontal (dynamic) mass changes are still difficult, and modelling of these changes remains underdeveloped in spite of recent advances. Thus research on a broad scale is called for in order to meet the challenge of producing more accurate hindcasts and projections of glacier mass budgets with fine spatial and temporal resolution.

  4. Using a body sensor network to measure the effect of fatigue on stair climbing performance

    International Nuclear Information System (INIS)

    Bergmann, Jeroen H M; Smith, Ian C H; Mayagoitia, Ruth E

    2012-01-01

    In terms of self-rated health, the most important activities of daily living are those involving mobility. Of these activities stair climbing is regarded as the most strenuous. A loss of stair climbing ability with age is normally associated with a loss of muscle strength and power, while other factors that influence muscle function, such as fatigue, are often not taken into account. So far no research has been published on how long-lasting fatigue affects activities of daily living, despite the fact that it has been repeatedly proven, in laboratory settings, to influence muscle force production over long periods of time. Technological advances in body sensor networks (BSNs) now provide a method to measure performance during complex real-life situations. In this study the use of a BSN was explored to investigate the effects of long-lasting fatigue on stair climbing performance in 20 healthy adults. Stair climbing performance was measured before and after a fatiguing protocol using a BSN. Performance was defined by temporal and spatial parameters. Long-lasting fatigue was successfully induced in all participants using an exercise protocol. The BSN showed that post-exercise fatigue did not influence stair climbing times (p > 0.2) and no meaningful changes in joint angles were found. No effect on overall stair climbing performance was found, despite a clear presence of long-lasting fatigue. This study shows that physiological paradigms can be further explored using BSNs. Ecological validity of lab-based measurements can be increased by combining them with BSNs. (paper)

  5. Research and development cooperation project on environmental measurement using laser radar (environmental network) in fiscal 1993; Kankyo keisokuyo laser radar no kaihatsu ni kansuru kenkyu kyoryoku (kankyo network)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-03-01

    For the purpose of contributing to the research cooperation project on the development of a laser radar for environmental measurement, the paper surveyed the present and future trend of the environment related information network in Indonesia. The survey was conducted in terms of a name of the network, the main administration body, the number of users, the utilization status, the use protocol, details of service, domestic mode installation sites and the main administration body, accounting system, types of the network used, reliability and stability of network, limitations on the use and details of the limitation, etc. The plan for expanding telecommunication equipment is being advanced in a very quick tempo. However, there are many problems in digitalization, and it is feared that the plan will be delayed. As to telecommunication quality and connection quality, the telecommunication completion rate, SCR, is very low, approximately 24% on average, which is equal to that around 1990 in Japan. The business service for users is all bureaucratic since they have a lot of applications for the installation piling up with no exception to the rule of developing countries. 23 figs., 10 tabs.

  6. A Newly Developed Method for Computing Reliability Measures in a Water Supply Network

    Directory of Open Access Journals (Sweden)

    Jacek Malinowski

    2016-01-01

    Full Text Available A reliability model of a water supply network has beens examined. Its main features are: a topology that can be decomposed by the so-called state factorization into a (relativelysmall number of derivative networks, each having a series-parallel structure (1, binary-state components (either operative or failed with given flow capacities (2, a multi-state character of the whole network and its sub-networks - a network state is defined as the maximal flow between a source (sources and a sink (sinks (3, all capacities (component, network, and sub-network have integer values (4. As the network operates, its state changes due to component failures, repairs, and replacements. A newly developed method of computing the inter-state transition intensities has been presented. It is based on the so-called state factorization and series-parallel aggregation. The analysis of these intensities shows that the failure-repair process of the considered system is an asymptotically homogenous Markov process. It is also demonstrated how certain reliability parameters useful for the network maintenance planning can be determined on the basis of the asymptotic intensities. For better understanding of the presented method, an illustrative example is given. (original abstract

  7. Calibration and performance measurements for the nasa deep space network aperture enhancement project (daep)

    Science.gov (United States)

    LaBelle, Remi C.; Rochblatt, David J.

    2018-06-01

    The NASA Deep Space Network (DSN) has recently constructed two new 34-m antennas at the Canberra Deep Space Communications Complex (CDSCC). These new antennas are part of the larger DAEP project to add six new 34-m antennas to the DSN, including two in Madrid, three in Canberra and one in Goldstone (California). The DAEP project included development and implementation of several new technologies for the X, and Ka (32 GHz) -band uplink and downlink electronics. The electronics upgrades were driven by several different considerations, including parts obsolescence, cost reduction, improved reliability and maintainability, and capability to meet future performance requirements. The new antennas are required to support TT&C links for all of the NASA deep-space spacecraft, as well as for several international partners. Some of these missions, such as Voyager 1 and 2, have very limited link budgets, which results in demanding requirements for system G/T performance. These antennas are also required to support radio science missions with several spacecraft, which dictate some demanding requirements for spectral purity, amplitude stability and phase stability for both the uplink and downlink electronics. After completion of these upgrades, a comprehensive campaign of tests and measurements took place to characterize the electronics and calibrate the antennas. Radiometric measurement techniques were applied to characterize, calibrate, and optimize the performance of the antenna parameters. These included optical and RF high-resolution holographic and total power radiometry techniques. The methodology and techniques utilized for the measurement and calibration of the antennas is described in this paper. Lessons learned (not all discussed in this paper) from the commissioning of the first antenna (DSS-35) were applied to the commissioning of the second antenna (DSS-36). These resulted in achieving antenna aperture efficiency of 66% (for DSS-36), at Ka-Band (32-Ghz), which is

  8. The effect of time duration in the network and radial method toward the accuracy in measuring the deformation at Muria

    International Nuclear Information System (INIS)

    Ari Nugroho and Hadi Suntoko

    2011-01-01

    The Deformation monitoring activities in the vicinity of Mount Muria are recommended by the IAEA (International Atomic Energy Agency) to be done for 5 years. The purpose of these activities is to determine the rate of the deformation caused by the volcanic activity of Mount Muria, as a basic study in analyzing the volcanic hazard toward the NPP (Nuclear Power Plant). The whole coordinate points measured encompass the district of Jepara, Pati, Demak, and Kudus. In 2010 deformation measurements were periodically conducted for 4 times a year using two geodetic GPS units of Trimble R7 GNSS type through the network method. The measurements were carried out at seven points of interest and at one reference point in March, April, May and December. Each session of the measurements was performed for 2.5 hours. In 2011 the deformation measurements were periodically conducted for 4 times a year by means of the radial method. The measurements were made at eight points of interest and at one reference point in April and May, June and July. Each session of measurements was performed for 10 hours. Based on the results of the measurements by means of the network method in 2010, it was concluded that the range of horizontal and vertical accuracy is between 6-10 mm and 25-46 mm, while the results of the measurements of the radial method in 2011 is 4-7 mm, and 16-28 mm respectively. Furthermore, it provides the evidence that the radial method tends to has better result than the network method if it is applied 4 times longer than the network method, resulting the accuracy below 7 mm and 28 mm for horizontal and vertical respectively. (author)

  9. Mapping the nomological network of employee self-determined safety motivation: A preliminary measure in China.

    Science.gov (United States)

    Jiang, Li; Tetrick, Lois E

    2016-09-01

    The present study introduced a preliminary measure of employee safety motivation based on the definition of self-determination theory from Fleming (2012) research and validated the structure of self-determined safety motivation (SDSM) by surveying 375 employees in a Chinese high-risk organization. First, confirmatory factor analysis (CFA) was used to examine the factor structure of SDSM, and indices of five-factor model CFA met the requirements. Second, a nomological network was examined to provide evidence of the construct validity of SDSM. Beyond construct validity, the analysis also produced some interesting results concerning the relationship between leadership antecedents and safety motivation, and between safety motivation and safety behavior. Autonomous motivation was positively related to transformational leadership, negatively related to abusive supervision, and positively related to safety behavior. Controlled motivation with the exception of introjected regulation was negatively related to transformational leadership, positively related to abusive supervision, and negatively related to safety behavior. The unique role of introjected regulation and future research based on self-determination theory were discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Reliability Measure Model for Assistive Care Loop Framework Using Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Venki Balasubramanian

    2010-01-01

    Full Text Available Body area wireless sensor networks (BAWSNs are time-critical systems that rely on the collective data of a group of sensor nodes. Reliable data received at the sink is based on the collective data provided by all the source sensor nodes and not on individual data. Unlike conventional reliability, the definition of retransmission is inapplicable in a BAWSN and would only lead to an elapsed data arrival that is not acceptable for time-critical application. Time-driven applications require high data reliability to maintain detection and responses. Hence, the transmission reliability for the BAWSN should be based on the critical time. In this paper, we develop a theoretical model to measure a BAWSN's transmission reliability, based on the critical time. The proposed model is evaluated through simulation and then compared with the experimental results conducted in our existing Active Care Loop Framework (ACLF. We further show the effect of the sink buffer in transmission reliability after a detailed study of various other co-existing parameters.

  11. Link importance incorporated failure probability measuring solution for multicast light-trees in elastic optical networks

    Science.gov (United States)

    Li, Xin; Zhang, Lu; Tang, Ying; Huang, Shanguo

    2018-03-01

    The light-tree-based optical multicasting (LT-OM) scheme provides a spectrum- and energy-efficient method to accommodate emerging multicast services. Some studies focus on the survivability technologies for LTs against a fixed number of link failures, such as single-link failure. However, a few studies involve failure probability constraints when building LTs. It is worth noting that each link of an LT plays different important roles under failure scenarios. When calculating the failure probability of an LT, the importance of its every link should be considered. We design a link importance incorporated failure probability measuring solution (LIFPMS) for multicast LTs under independent failure model and shared risk link group failure model. Based on the LIFPMS, we put forward the minimum failure probability (MFP) problem for the LT-OM scheme. Heuristic approaches are developed to address the MFP problem in elastic optical networks. Numerical results show that the LIFPMS provides an accurate metric for calculating the failure probability of multicast LTs and enhances the reliability of the LT-OM scheme while accommodating multicast services.

  12. Ad-hoc Network of Smart Sensors for Mechanical Load Measurement

    Directory of Open Access Journals (Sweden)

    Manuel A. Vieira

    2016-07-01

    Full Text Available Strain gauges load cells are transducers devices capable of converting changes in applied mechanical load into an electrical analog signal. Those devices have a large spectrum of applications ranging from domestic to industrial or even medical appliances just to name a few. In this work, they are used in the electronic instrumentation of a force platform that will be used to carry out the analysis and characterization of human biomechanical walking. In this platform, four load cells are installed, each one capable of measuring forces along two different axis. A total of eight strain-gauges per load cell are employed. Hence, analog signal transmission, besides requiring a large number of connection wires, is prone to interference and noise. Moreover, with this solution, scalability requires severe changes in the connection topology. In order to circumvent those problems, an alternative in-situ signal conditioning and digital data transmission system was devised. This approach, as far as investigated, presents an innovative solution to signal conditioning and data transmission for load-cells. In particular, the presented solution allows the creation of an ad-hoc network of load cells, using the I²C protocol with a master interface that allows the users to interact and change the parameters of each load cell. This instrumentation structure has been successfully tested and the obtained results are documented in this article.

  13. Measurement of the top pair production cross section at CDF using neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Marginean, Radu [The Ohio State Univ., Columbus, OH (United States)

    2004-01-01

    background processes. A neural network technique is employed to combine multiple variables in order to enhance signal versus background separation. Such a measurement takes advantage of a larger data sample than the b-tagging based analyses and achieves a comparable level of precision. A binned likelihood fit to the neural network output distribution for a 519 events data sample yields a 17.6 ± 3.0(stat)% fraction of t$\\bar{t}$ events. The inclusive top pair production cross section is measured to be σt$\\bar{t}$ = 6.6 ± 1.1(stat) ± 1.5(syst) pb.

  14. Performance Analysis with Network-Enhanced Complexities: On Fading Measurements, Event-Triggered Mechanisms, and Cyber Attacks

    Directory of Open Access Journals (Sweden)

    Derui Ding

    2014-01-01

    Full Text Available Nowadays, the real-world systems are usually subject to various complexities such as parameter uncertainties, time-delays, and nonlinear disturbances. For networked systems, especially large-scale systems such as multiagent systems and systems over sensor networks, the complexities are inevitably enhanced in terms of their degrees or intensities because of the usage of the communication networks. Therefore, it would be interesting to (1 examine how this kind of network-enhanced complexities affects the control or filtering performance; and (2 develop some suitable approaches for controller/filter design problems. In this paper, we aim to survey some recent advances on the performance analysis and synthesis with three sorts of fashionable network-enhanced complexities, namely, fading measurements, event-triggered mechanisms, and attack behaviors of adversaries. First, these three kinds of complexities are introduced in detail according to their engineering backgrounds, dynamical characteristic, and modelling techniques. Then, the developments of the performance analysis and synthesis issues for various networked systems are systematically reviewed. Furthermore, some challenges are illustrated by using a thorough literature review and some possible future research directions are highlighted.

  15. AziSA: an architecture for underground measurement and control networks - 2nd International Conference on Wireless Communications...

    CSIR Research Space (South Africa)

    Stewart, R

    2008-08-01

    Full Text Available AziSA is an architecture for measurement and control networks that can be used to collect, store and facilitate the analysis of data from challenging underground environments. AziSA defines four node classes, two (Classes Four and Three...

  16. Influence of Landscape Coverage on Measuring Spatial and Length Properties of Rock Fracture Networks: Insights from Numerical Simulation

    Science.gov (United States)

    Cao, Wenzhuo; Lei, Qinghua

    2018-01-01

    Natural fractures are ubiquitous in the Earth's crust and often deeply buried in the subsurface. Due to the difficulty in accessing to their three-dimensional structures, the study of fracture network geometry is usually achieved by sampling two-dimensional (2D) exposures at the Earth's surface through outcrop mapping or aerial photograph techniques. However, the measurement results can be considerably affected by the coverage of forests and other plant species over the exposed fracture patterns. We quantitatively study such effects using numerical simulation. We consider the scenario of nominally isotropic natural fracture systems and represent them using 2D discrete fracture network models governed by fractal and length scaling parameters. The groundcover is modelled as random patches superimposing onto the 2D fracture patterns. The effects of localisation and total coverage of landscape patches are further investigated. The fractal dimension and length exponent of the covered fracture networks are measured and compared with those of the original non-covered patterns. The results show that the measured length exponent increases with the reduced localisation and increased coverage of landscape patches, which is more evident for networks dominated by very large fractures (i.e. small underlying length exponent). However, the landscape coverage seems to have a minor impact on the fractal dimension measurement. The research findings of this paper have important implications for field survey and statistical analysis of geological systems.

  17. Measurement based analysis of active and reactive power losses in a distribution network with wind farms and CHPs

    DEFF Research Database (Denmark)

    Lund, Torsten

    2007-01-01

    The paper presents an investigation of the active and reactive power losses in a distribution network with wind turbines and combined heat and power plants. The investigation is based on 15 min average power measurements and load flow calculations in the power system simulation tool PowerFactory...

  18. Equal Graph Partitioning on Estimated Infection Network as an Effective Epidemic Mitigation Measure

    Science.gov (United States)

    Hadidjojo, Jeremy; Cheong, Siew Ann

    2011-01-01

    Controlling severe outbreaks remains the most important problem in infectious disease area. With time, this problem will only become more severe as population density in urban centers grows. Social interactions play a very important role in determining how infectious diseases spread, and organization of people along social lines gives rise to non-spatial networks in which the infections spread. Infection networks are different for diseases with different transmission modes, but are likely to be identical or highly similar for diseases that spread the same way. Hence, infection networks estimated from common infections can be useful to contain epidemics of a more severe disease with the same transmission mode. Here we present a proof-of-concept study demonstrating the effectiveness of epidemic mitigation based on such estimated infection networks. We first generate artificial social networks of different sizes and average degrees, but with roughly the same clustering characteristic. We then start SIR epidemics on these networks, censor the simulated incidences, and use them to reconstruct the infection network. We then efficiently fragment the estimated network by removing the smallest number of nodes identified by a graph partitioning algorithm. Finally, we demonstrate the effectiveness of this targeted strategy, by comparing it against traditional untargeted strategies, in slowing down and reducing the size of advancing epidemics. PMID:21799777

  19. Measuring, Understanding, and Responding to Covert Social Networks: Passive and Active Tomography

    Science.gov (United States)

    2017-11-11

    Methods for generating a random sample of networks with desired properties are important tools for the analysis of social , biological, and information...on Theoretical Foundations for Statistical Network Analysis at the Isaac Newton Institute for Mathematical Sciences at Cambridge U. (organized by...Approach SOCIAL SCIENCES STATISTICS EECS Problems span three disciplines Scientific focus is needed at the interfaces

  20. Assessment of voltage dips based on field measurements in MV networks

    NARCIS (Netherlands)

    Weldemariam, L.E.; Papathanasiou, F.; Cuk, V.; Cobben, J.F.G.; Kling, W.L.

    Voltage dip is considered as the PQ problem related to the highest financial losses for the customers. It occurs unpredictably mainly due to short-circuit faults in the networks. Network operators and customers want to know more about the occurrence and the potential impact of voltage dips. PQ

  1. On Goodput and Energy Measurements of Network Coding Schemes in the Raspberry Pi

    DEFF Research Database (Denmark)

    Hernandez, Nestor; Sørensen, Chres Wiant; Cabrera, Juan

    2016-01-01

    Given that next generation networks are expected to be populated by a large number of devices, there is a need for quick deployment and evaluation of alternative mechanisms to cope with the possible generated traffic in large-scale distributed data networks. In this sense, the Raspberry Pi has be...

  2. Tower-Based Greenhouse Gas Measurement Network Design---The National Institute of Standards and Technology North East Corridor Testbed.

    Science.gov (United States)

    Lopez-Coto, Israel; Ghosh, Subhomoy; Prasad, Kuldeep; Whetstone, James

    2017-09-01

    The North-East Corridor (NEC) Testbed project is the 3rd of three NIST (National Institute of Standards and Technology) greenhouse gas emissions testbeds designed to advance greenhouse gas measurements capabilities. A design approach for a dense observing network combined with atmospheric inversion methodologies is described. The Advanced Research Weather Research and Forecasting Model with the Stochastic Time-Inverted Lagrangian Transport model were used to derive the sensitivity of hypothetical observations to surface greenhouse gas emissions (footprints). Unlike other network design algorithms, an iterative selection algorithm, based on a k -means clustering method, was applied to minimize the similarities between the temporal response of each site and maximize sensitivity to the urban emissions contribution. Once a network was selected, a synthetic inversion Bayesian Kalman filter was used to evaluate observing system performance. We present the performances of various measurement network configurations consisting of differing numbers of towers and tower locations. Results show that an overly spatially compact network has decreased spatial coverage, as the spatial information added per site is then suboptimal as to cover the largest possible area, whilst networks dispersed too broadly lose capabilities of constraining flux uncertainties. In addition, we explore the possibility of using a very high density network of lower cost and performance sensors characterized by larger uncertainties and temporal drift. Analysis convergence is faster with a large number of observing locations, reducing the response time of the filter. Larger uncertainties in the observations implies lower values of uncertainty reduction. On the other hand, the drift is a bias in nature, which is added to the observations and, therefore, biasing the retrieved fluxes.

  3. Directed weighted network structure analysis of complex impedance measurements for characterizing oil-in-water bubbly flow.

    Science.gov (United States)

    Gao, Zhong-Ke; Dang, Wei-Dong; Xue, Le; Zhang, Shan-Shan

    2017-03-01

    Characterizing the flow structure underlying the evolution of oil-in-water bubbly flow remains a contemporary challenge of great interests and complexity. In particular, the oil droplets dispersing in a water continuum with diverse size make the study of oil-in-water bubbly flow really difficult. To study this issue, we first design a novel complex impedance sensor and systematically conduct vertical oil-water flow experiments. Based on the multivariate complex impedance measurements, we define modalities associated with the spatial transient flow structures and construct modality transition-based network for each flow condition to study the evolution of flow structures. In order to reveal the unique flow structures underlying the oil-in-water bubbly flow, we filter the inferred modality transition-based network by removing the edges with small weight and resulting isolated nodes. Then, the weighted clustering coefficient entropy and weighted average path length are employed for quantitatively assessing the original network and filtered network. The differences in network measures enable to efficiently characterize the evolution of the oil-in-water bubbly flow structures.

  4. Automated processing of measuring information and control processes of eutrophication in water for household purpose, based on artificial neural networks

    Directory of Open Access Journals (Sweden)

    О.М. Безвесільна

    2006-04-01

    Full Text Available  The possibilities of application  informational-computer technologies for automated handling of a measuring information about development of seaweed (evtrofication in household reservoirs are considered. The input data’s for a research of processes evtrofication are videoimages of tests of water, which are used for the definition of geometric characteristics, number and biomass of seaweed. For handling a measuring information the methods of digital handling videoimages and mathematical means of artificial neural networks are offered.

  5. Network cohesion

    OpenAIRE

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

    2017-01-01

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

  6. Optimized probes for dose rate measurements at local government sites and in emergency planning zones and their integration into measurement networks

    International Nuclear Information System (INIS)

    Kuca, Petr; Helebrant, Jan; Cespirova, Irena; Judas, Libor; Skala, Lukas

    2015-01-01

    The results of a security project aimed at the development of a radiation situation monitoring system using optimized probes for dose rate measurements are described. The system is suitable for use at local government sites as well as at other sites. The system includes dose rate measurement probes with the variable configuration functionality (detection part), equipment for data transfer to a central workplace (communication part) and application for collection, storage and administration of the results and their presentation at a website (presentation part). The dosimetric and other operational properties of the probes were tested and the feasibility of their integration into measurement networks using the IMS central application was examined. (orig.)

  7. Variation of the Korotkoff Stethoscope Sounds During Blood Pressure Measurement: Analysis Using a Convolutional Neural Network.

    Science.gov (United States)

    Pan, Fan; He, Peiyu; Liu, Chengyu; Li, Taiyong; Murray, Alan; Zheng, Dingchang

    2017-11-01

    Korotkoff sounds are known to change their characteristics during blood pressure (BP) measurement, resulting in some uncertainties for systolic and diastolic pressure (SBP and DBP) determinations. The aim of this study was to assess the variation of Korotkoff sounds during BP measurement by examining all stethoscope sounds associated with each heartbeat from above systole to below diastole during linear cuff deflation. Three repeat BP measurements were taken from 140 healthy subjects (age 21 to 73 years; 62 female and 78 male) by a trained observer, giving 420 measurements. During the BP measurements, the cuff pressure and stethoscope signals were simultaneously recorded digitally to a computer for subsequent analysis. Heartbeats were identified from the oscillometric cuff pressure pulses. The presence of each beat was used to create a time window (1 s, 2000 samples) centered on the oscillometric pulse peak for extracting beat-by-beat stethoscope sounds. A time-frequency two-dimensional matrix was obtained for the stethoscope sounds associated with each beat, and all beats between the manually determined SBPs and DBPs were labeled as "Korotkoff." A convolutional neural network was then used to analyze consistency in sound patterns that were associated with Korotkoff sounds. A 10-fold cross-validation strategy was applied to the stethoscope sounds from all 140 subjects, with the data from ten groups of 14 subjects being analyzed separately, allowing consistency to be evaluated between groups. Next, within-subject variation of the Korotkoff sounds analyzed from the three repeats was quantified, separately for each stethoscope sound beat. There was consistency between folds with no significant differences between groups of 14 subjects (P = 0.09 to P = 0.62). Our results showed that 80.7% beats at SBP and 69.5% at DBP were analyzed as Korotkoff sounds, with significant differences between adjacent beats at systole (13.1%, P = 0.001) and diastole (17.4%, P < 0

  8. Gap assessment in current soil monitoring networks across Europe for measuring soil functions

    Science.gov (United States)

    van Leeuwen, J. P.; Saby, N. P. A.; Jones, A.; Louwagie, G.; Micheli, E.; Rutgers, M.; Schulte, R. P. O.; Spiegel, H.; Toth, G.; Creamer, R. E.

    2017-12-01

    Soil is the most important natural resource for life on Earth after water. Given its fundamental role in sustaining the human population, both the availability and quality of soil must be managed sustainably and protected. To ensure sustainable management we need to understand the intrinsic functional capacity of different soils across Europe and how it changes over time. Soil monitoring is needed to support evidence-based policies to incentivise sustainable soil management. To this aim, we assessed which soil attributes can be used as potential indicators of five soil functions; (1) primary production, (2) water purification and regulation, (3) carbon sequestration and climate regulation, (4) soil biodiversity and habitat provisioning and (5) recycling of nutrients. We compared this list of attributes to existing national (regional) and EU-wide soil monitoring networks. The overall picture highlighted a clearly unbalanced dataset, in which predominantly chemical soil parameters were included, and soil biological and physical attributes were severely under represented. Methods applied across countries for indicators also varied. At a European scale, the LUCAS-soil survey was evaluated and again confirmed a lack of important soil biological parameters, such as C mineralisation rate, microbial biomass and earthworm community, and soil physical measures such as bulk density. In summary, no current national or European monitoring system exists which has the capacity to quantify the five soil functions and therefore evaluate multi-functional capacity of a soil and in many countries no data exists at all. This paper calls for the addition of soil biological and some physical parameters within the LUCAS-soil survey at European scale and for further development of national soil monitoring schemes.

  9. Study of the dose rate measured by the radiological surveillance network of the Basque country

    International Nuclear Information System (INIS)

    Alegria, N.; Legarda, F.; Herranz, M.

    2006-01-01

    Full text of publication follows: The radiological Surveillance Network of the Basque Country, which is constituted by three stations located in Bilbao, Vitoria and San Sebastian, measures and records the dose date every 10 minutes. Some environmental parameters affect the behaviour of the dose rate. One of most important meteorological parameters is rain. So, it has been necessary to study separately the behaviour of dose rate in the absence of rain, defining that time as Dry Time, and the behaviour when it rains, designating that time as Wet Time. Previous studies have confirmed that dose rate values are fitted to normal distributions, and in those cases, Critical Limits can be calculated using Curie formulation. Every January, data recorded in previous year, two Critical Limits are obtained, one of them for dry time and other one for wet time, and both together define the Alarm Level for each radiological station. That Alarm Level is the reference value for dose rate. If some dose rate value is higher than the corresponding Alarm Level, the recorded values have to be studied in order to identify the origin or the cause of that value. In most cases, in which the dose rate is higher than the corresponding Alarm Level due to precipitation, occurs that when rain stops the dose rate value does not fall immediately to dry rime values, and then the Alarm Level which is now that for dry time is exceeded by the dose rate. So, those values can be considered a special group called Transition Area. The second part of the study tries to explain the cause and the behaviour of the values in the transition Area by means of the study of the behaviour of radon daughters in the atmosphere and their deposition onto the ground during rain intervals. To check the results several situations have been simulated using the Monte Carlo code MCNP-4C. (authors)

  10. Acoustic measurement of sediment dynamics in the coastal zones using wireless sensor networks

    Science.gov (United States)

    Sudhakaran, A., II; Paramasivam, A.; Seshachalam, S.; A, C.

    2014-12-01

    Analyzing of the impact of constructive or low energy waves and deconstructive or high energy waves in the ocean are very much significant since they deform the geometry of seashore. The deformation may lead to productive result and also to the end of deteriorate damage. Constructive waves results deposition of sediment which widens the beach where as deconstructive waves results erosion which narrows the beach. Validation of historic sediment transportation and prediction of the direction of movement of seashore is essential to prevent unrecoverable damages by incorporating precautionary measurements to identify the factors that influence sediment transportation if feasible. The objective of this study is to propose a more reliable and energy efficient Information and communication system to model the Coastal Sediment Dynamics. Various factors influencing the sediment drift at a particular region is identified. Consequence of source depth and frequency dependencies of spread pattern in the presence of sediments is modeled. Property of source depth and frequency on sensitivity to values of model parameters are determined. Fundamental physical reasons for these sediment interaction effects are given. Shallow to deep water and internal and external wave model of ocean is obtained intended to get acoustic data assimilation (ADA). Signal processing algorithms are used over the observed data to form a full field acoustic propagation model and construct sound speed profile (SSP). The inversions of data due to uncertainties at various depths are compared. The impact of sediment drift over acoustic data is identified. An energy efficient multipath routing scheme Wireless sensor networks (WSN) is deployed for the well-organized communication of data. The WSN is designed considering increased life time, decreased power consumption, free of threats and attacks. The practical data obtained from the efficient system to model the ocean sediment dynamics are evaluated with remote

  11. The Hetu'u Global Network: Measuring the Distance to the Sun with the Transit of Venus

    Science.gov (United States)

    Rodriguez, David; Faherty, J.

    2013-01-01

    In the spirit of historic astronomical endeavors, we invited school groups across the globe to collaborate in a solar distance measurement using the 2012 transit of Venus. In total, our group (stationed at Easter Island, Chile) recruited 19 school groups spread over 6 continents and 10 countries to participate in our Hetu’u Global Network. Applying the methods of French astronomer Joseph-Nicolas Delisle, we used individual second and third Venus-Sun contact times to calculate the distance to the Sun. Ten of the sites in our network had amiable weather; 8 of which measured second contact and 5 of which measured third contact leading to consistent solar distance measurements of 152+/-30 million km and 163+/-30 million km respectively. The distance to the Sun at the time of the transit was 152.25 million km; therefore, our measurements are also consistent within 1-sigma of the known value. The goal of our international school group network was to inspire the next generation of scientists using the excitement and accessibility of such a rare astronomical event. In the process, we connected hundreds of participating students representing a diverse, multi-cultural group with differing political, economic, and racial backgrounds.

  12. Design and Optimization of Capacitated Supply Chain Networks Including Quality Measures

    Directory of Open Access Journals (Sweden)

    Krystel K. Castillo-Villar

    2014-01-01

    Full Text Available This paper presents (1 a novel capacitated model for supply chain network design which considers manufacturing, distribution, and quality costs (named SCND-COQ model and (2 five combinatorial optimization methods, based on nonlinear optimization, heuristic, and metaheuristic approaches, which are used to solve realistic instances of practical size. The SCND-COQ model is a mixed-integer nonlinear problem which can be used at a strategic planning level to design a supply chain network that maximizes the total profit subject to meeting an overall quality level of the final product at minimum costs. The SCND-COQ model computes the quality-related costs for the whole supply chain network considering the interdependencies among business entities. The effectiveness of the proposed solution approaches is shown using numerical experiments. These methods allow solving more realistic (capacitated supply chain network design problems including quality-related costs (inspections, rework, opportunity costs, and others within a reasonable computational time.

  13. 75 FR 33303 - Comment Sought on Measurement of Mobile Broadband Network Performance and Coverage

    Science.gov (United States)

    2010-06-11

    ... on fixed residential and small business Internet broadband services. With that public notice, the...., smartphone, feature phones, laptop, wireless modem) itself have on end-user experienced network performance...

  14. Using mobile probes to inform and measure the effectiveness of traffic control strategies on urban networks.

    Science.gov (United States)

    2015-07-01

    Urban traffic congestion is a problem that plagues many cities in the United States. Testing strategies to alleviate this : congestion is especially challenging due to the difficulty of modeling complex urban traffic networks. However, recent work ha...

  15. Measuring Spatial Distribution Characteristics of Heavy Metal Contaminations in a Network-Constrained Environment: A Case Study in River Network of Daye, China

    Directory of Open Access Journals (Sweden)

    Zhensheng Wang

    2017-06-01

    Full Text Available Measuring the spatial distribution of heavy metal contaminants is the basis of pollution evaluation and risk control. Considering the cost of soil sampling and analysis, spatial interpolation methods have been widely applied to estimate the heavy metal concentrations at unsampled locations. However, traditional spatial interpolation methods assume the sample sites can be located stochastically on a plane and the spatial association between sample locations is analyzed using Euclidean distances, which may lead to biased conclusions in some circumstances. This study aims to analyze the spatial distribution characteristics of copper and lead contamination in river sediments of Daye using network spatial analysis methods. The results demonstrate that network inverse distance weighted interpolation methods are more accurate than planar interpolation methods. Furthermore, the method named local indicators of network-constrained clusters based on local Moran’ I statistic (ILINCS is applied to explore the local spatial patterns of copper and lead pollution in river sediments, which is helpful for identifying the contaminated areas and assessing heavy metal pollution of Daye.

  16. Multiscale Pore Throat Network Reconstruction of Tight Porous Media Constrained by Mercury Intrusion Capillary Pressure and Nuclear Magnetic Resonance Measurements

    Science.gov (United States)

    Xu, R.; Prodanovic, M.

    2017-12-01

    Due to the low porosity and permeability of tight porous media, hydrocarbon productivity strongly depends on the pore structure. Effective characterization of pore/throat sizes and reconstruction of their connectivity in tight porous media remains challenging. Having a representative pore throat network, however, is valuable for calculation of other petrophysical properties such as permeability, which is time-consuming and costly to obtain by experimental measurements. Due to a wide range of length scales encountered, a combination of experimental methods is usually required to obtain a comprehensive picture of the pore-body and pore-throat size distributions. In this work, we combine mercury intrusion capillary pressure (MICP) and nuclear magnetic resonance (NMR) measurements by percolation theory to derive pore-body size distribution, following the work by Daigle et al. (2015). However, in their work, the actual pore-throat sizes and the distribution of coordination numbers are not well-defined. To compensate for that, we build a 3D unstructured two-scale pore throat network model initialized by the measured porosity and the calculated pore-body size distributions, with a tunable pore-throat size and coordination number distribution, which we further determine by matching the capillary pressure vs. saturation curve from MICP measurement, based on the fact that the mercury intrusion process is controlled by both the pore/throat size distributions and the connectivity of the pore system. We validate our model by characterizing several core samples from tight Middle East carbonate, and use the network model to predict the apparent permeability of the samples under single phase fluid flow condition. Results show that the permeability we get is in reasonable agreement with the Coreval experimental measurements. The pore throat network we get can be used to further calculate relative permeability curves and simulate multiphase flow behavior, which will provide valuable

  17. A measurement-driven approach to assess power line telecommunication (PLT) network quality of service (QoS) performance parameters

    International Nuclear Information System (INIS)

    Betta, G; Capriglione, D; Ferrigno, L; Laracca, M

    2009-01-01

    Power line telecommunication (PLT) technology offers cheap and fast ways for providing in-home broadband services and local area networking. Its main advantage is due to the possibility of using the pre-existing electrical grid as a communication channel. Nevertheless, technical challenges arise from the difficulty of operating on a hostile medium, not designed for communication purposes, characterized by complex channel modeling and by varying time response. These aspects put practical problems for designers and testers in the assessment of network quality of service performance parameters such as the throughput, the latency, the jitter, and the reliability. The measurement of these parameters has not yet been standardized so that there do not exist reference test set-ups and measurement methodologies (i.e. the type of isolation from the ac main, the observation time and the number of experiments, the measurement uncertainty and so on). Consequently, experiments executed by adopting different methods may lead to incompatible measurement results, thus making it also impossible to have reliable comparisons of different PLT modems. Really, the development of standard procedures is a very difficult task because the scenarios in which the PLT modems can work are very wide and then the application of an exhaustive approach (in which all the parameters influencing the PLT performance should be considered) would be very complex and time consuming, thus making the modem characterization very expensive. In this paper, the authors propose a methodological approach to develop an efficient measurement procedure able to reliably assess the performance of PLT modems (in terms of network quality of service parameters) with a minimum number of experiments. It is based on both creating a reconfigurable grid to which real disturbing loads are connected and implementing an original design of the experiment technique based on the effects of the uncertainty of the measurement results

  18. Elucidating MicroRNA Regulatory Networks Using Transcriptional, Post-transcriptional, and Histone Modification Measurements

    Directory of Open Access Journals (Sweden)

    Sara J.C. Gosline

    2016-01-01

    Full Text Available MicroRNAs (miRNAs regulate diverse biological processes by repressing mRNAs, but their modest effects on direct targets, together with their participation in larger regulatory networks, make it challenging to delineate miRNA-mediated effects. Here, we describe an approach to characterizing miRNA-regulatory networks by systematically profiling transcriptional, post-transcriptional and epigenetic activity in a pair of isogenic murine fibroblast cell lines with and without Dicer expression. By RNA sequencing (RNA-seq and CLIP (crosslinking followed by immunoprecipitation sequencing (CLIP-seq, we found that most of the changes induced by global miRNA loss occur at the level of transcription. We then introduced a network modeling approach that integrated these data with epigenetic data to identify specific miRNA-regulated transcription factors that explain the impact of miRNA perturbation on gene expression. In total, we demonstrate that combining multiple genome-wide datasets spanning diverse regulatory modes enables accurate delineation of the downstream miRNA-regulated transcriptional network and establishes a model for studying similar networks in other systems.

  19. Making better sense of the mosaic of environmental measurement networks: a system-of-systems approach and quantitative assessment

    Directory of Open Access Journals (Sweden)

    P. W. Thorne

    2017-11-01

    Full Text Available There are numerous networks and initiatives concerned with the non-satellite-observing segment of Earth observation. These are owned and operated by various entities and organisations often with different practices, norms, data policies, etc. The Horizon 2020 project GAIA–CLIM is working to improve our collective ability to use an appropriate subset of these observations to rigorously characterise satellite observations. The first fundamental question is which observations from the mosaic of non-satellite observational capabilities are appropriate for such an application. This requires an assessment of the relevant, quantifiable aspects of the measurement series which are available. While fundamentally poor or incorrect measurements can be relatively easily identified, it is metrologically impossible to be sure that a measurement series is correct. Certain assessable aspects of the measurement series can, however, build confidence in their scientific maturity and appropriateness for given applications. These are aspects such as that it is well documented, well understood, representative, updated, publicly available and maintains rich metadata. Entities such as the Global Climate Observing System have suggested a hierarchy of networks whereby different subsets of the observational capabilities are assigned to different layers based on such assessable aspects. Herein, we make a first attempt to formalise both such a system-of-systems networks concept and a means by which to, as objectively as possible, assess where in this framework different networks may reside. In this study, we concentrate on networks measuring primarily a subset of the atmospheric Essential Climate Variables of interest to GAIA–CLIM activities. We show assessment results from our application of the guidance and how we plan to use this in downstream example applications of the GAIA–CLIM project. However, the approach laid out should be more widely applicable across

  20. An economic model of friendship and enmity for measuring social balance in networks

    Science.gov (United States)

    Lee, Kyu-Min; Shin, Euncheol; You, Seungil

    2017-12-01

    We propose a dynamic economic model of networks where agents can be friends or enemies with one another. This is a decentralized relationship model in that agents decide whether to change their relationships so as to minimize their imbalanced triads. In this model, there is a single parameter, which we call social temperature, that captures the degree to which agents care about social balance in their relationships. We show that the global structure of relationship configuration converges to a unique stationary distribution. Using this stationary distribution, we characterize the maximum likelihood estimator of the social temperature parameter. Since the estimator is computationally challenging to calculate from real social network datasets, we provide a simple simulation algorithm and verify its performance with real social network datasets.

  1. Prediction of Force Measurements of a Microbend Sensor Based on an Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Kemal Fidanboylu

    2009-09-01

    Full Text Available Artificial neural network (ANN based prediction of the response of a microbend fiber optic sensor is presented. To the best of our knowledge no similar work has been previously reported in the literature. Parallel corrugated plates with three deformation cycles, 6 mm thickness of the spacer material and 16 mm mechanical periodicity between deformations were used in the microbend sensor. Multilayer Perceptron (MLP with different training algorithms, Radial Basis Function (RBF network and General Regression Neural Network (GRNN are used as ANN models in this work. All of these models can predict the sensor responses with considerable errors. RBF has the best performance with the smallest mean square error (MSE values of training and test results. Among the MLP algorithms and GRNN the Levenberg-Marquardt algorithm has good results. These models successfully predict the sensor responses, hence ANNs can be used as useful tool in the design of more robust fiber optic sensors.

  2. Measuring the Influence of Information Networks on Transaction Costs Using a Non-parametric Regression Technique

    DEFF Research Database (Denmark)

    Henningsen, Geraldine; Henningsen, Arne; Henning, Christian

    2011-01-01

    All business transactions as well as achieving innovations take up resources, subsumed under the concept of transaction costs (TAC). One of the major factors in TAC theory is information. Information networks can catalyse the interpersonal information exchange and hence, increase the access...... to nonpublic information. Our analysis shows that information networks have an impact on the level of TAC. Many resources that are sacrificed for TAC are inputs that also enter the technical production process. As most production data do not separate between these two usages of inputs, high transaction costs...

  3. Smart thermal networks for smart cities - Introduction of concepts and measures

    Science.gov (United States)

    Schmidt, R. R.; Pol, O.; Basciotti, D.; Page, J.

    2012-10-01

    In order to contribute to high living standards, climate mitigation and energy supply security, future urban energy systems require a holistic approach. In particular an intelligent integration of thermal networks is necessary. This paper will briefly present the "smart city" concept and introduce an associated definition for smart thermal networks defined on three levels: 1. the interaction with urban planning processes and the interface to the overall urban energy system, 2. the adaptation of the temperature level and 3. supply and demand-side management strategies.

  4. Smart thermal networks for smart cities – Introduction of concepts and measures

    Directory of Open Access Journals (Sweden)

    Basciotti D.

    2012-10-01

    Full Text Available In order to contribute to high living standards, climate mitigation and energy supply security, future urban energy systems require a holistic approach. In particular an intelligent integration of thermal networks is necessary. This paper will briefly present the “smart city” concept and introduce an associated definition for smart thermal networks defined on three levels: 1. the interaction with urban planning processes and the interface to the overall urban energy system, 2. the adaptation of the temperature level and 3. supply and demand-side management strategies.

  5. The concept for development of the research network for the measurements of modern tectonic movements in Ksiaz Landscape Park

    Directory of Open Access Journals (Sweden)

    Damian Kasza

    2013-09-01

    Full Text Available The paper presents the concept for the development of research network for measurements of effects related to modern tectonic activity in the area of Ksiaz Landscape Park. The first evidences for the existence of displacements on the surfaces of discontinuity with event characteristic and the instruments used in the study were described. The way and shape of development of Ksiaz geodynamic polygon were characterized as well as the methodology and purpose of observations.

  6. $\\mu / \\pi$ Separation using Convolutional Neural Networks for the MicroBooNE Charged Current Inclusive Cross Section Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel, Jessica Nicole [Syracuse U.

    2018-01-01

    The purpose of this thesis was to use Convolutional Neural Networks (CNN) to separate $\\mu^{\\prime}$s and $\\pi^{\\prime}$s for use in increasing the acceptance rate of $\\mu^{\\prime}$s below the implemented 75cm track length cut in the Charged Current Inclusive (CC-Inclusive) event selection for the CC-Inclusive Cross-Section Measurement. In doing this, we increase acceptance rate for CC-Inclusive events below a specific momentum range.

  7. Measuring networks for environmental radioactivity monitoring in the European Community, - a pattern of diversity as varying as the peoples?

    International Nuclear Information System (INIS)

    Maushart, R.

    1991-01-01

    A new study entitled 'Monitoring of Environmental Radioactivity in the European Community', (RAES, 90), shows a survey of the methods currently applied in every country. The study compiles available quality assurance programs and makes suggestions for CEC initiatives. The study refers to the current practice of monitoring in European countries as 'enormous diversity of methods' in member countries. Further suggestions for standardization of the data measuring networks are put forward by a manufacturer of monitoring equipment. (orig./DG) [de

  8. A microfluidic device for simultaneous measurement of viscosity and flow rate of blood in a complex fluidic network

    OpenAIRE

    Jun Kang, Yang; Yeom, Eunseop; Lee, Sang-Joon

    2013-01-01

    Blood viscosity has been considered as one of important biophysical parameters for effectively monitoring variations in physiological and pathological conditions of circulatory disorders. Standard previous methods make it difficult to evaluate variations of blood viscosity under cardiopulmonary bypass procedures or hemodialysis. In this study, we proposed a unique microfluidic device for simultaneously measuring viscosity and flow rate of whole blood circulating in a complex fluidic network i...

  9. Aspects Regarding the Establishment of the Scale Coefficient in the Case of Distances Measurements in an Geodetic Network

    Directory of Open Access Journals (Sweden)

    Mircea Ortelecan

    2016-11-01

    Full Text Available The paper analyzes the possibility to establish the coefficient of scale towards the total station scale triangulation network in the conduct of geodetic and topographic observations in the points with known coordinates (old points or points whose coordinates we want to determine (new points. The purpose of the study is undertaken to simplify computing operations to reduce distances measured from the topographic surface to the Stereo 70 projection plan.

  10. Exploring Vietnamese co-authorship patterns in social sciences with basic network measures of 2008-2017 Scopus data [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Tung Manh Ho

    2017-08-01

    Full Text Available Background: Collaboration is a common occurrence among Vietnamese scientists; however, insights into Vietnamese scientific collaborations have been scarce. On the other hand, the application of social network analysis in studying science collaboration has gained much attention all over the world. The technique could be employed to explore Vietnam’s scientific community. Methods: This paper employs network theory to explore characteristics of a network of 412 Vietnamese social scientists whose papers can be found indexed in the Scopus database. Two basic network measures, density and clustering coefficient, were taken, and the entire network was studied in comparison with two of its largest components. Results: The networks connections are very sparse, with a density of only 0.47%, while the clustering coefficient is very high (58.64%. This suggests an inefficient dissemination of information, knowledge, and expertise in the network. Secondly, the disparity in levels of connection among individuals indicates that the network would easily fall apart if a few highly-connected nodes are removed. Finally, the two largest components of the network were found to differ from the entire networks in terms of measures and were both led by the most productive and well-connected researchers. Conclusions: High clustering and low density seems to be tied to inefficient dissemination of expertise among Vietnamese social scientists, and consequently low scientific output. Also low in robustness, the network shows the potential of an intellectual elite composed of well-connected, productive, and socially significant individuals.

  11. Assessment of Performance Measures for Security of the Maritime Transportation Network. Port Security Metrics: Proposed Measurement of Deterrence Capability

    National Research Council Canada - National Science Library

    Hoaglund, Robert; Gazda, Walter

    2007-01-01

    The goal of this analysis is to provide ASCO and its customers with a comprehensive approach to the development of quantitative performance measures to assess security improvements to the port system...

  12. Measuring the impact of negative demand shocks on car dealer networks

    NARCIS (Netherlands)

    Albuquerque, P.; Bronnenberg, B.J.

    2012-01-01

    The goal of this paper is to study the behavior of consumers, dealers, and manufacturers in the car sector and present an approach that can be used by managers and policy makers to investigate the impact of significant demand shocks on profits, prices, and dealer networks. More specifically, we

  13. Measuring Teacher Knowledge of Classroom Social Networks: Convergent and Predictive Validity in Elementary School Classrooms

    Science.gov (United States)

    Madill, Rebecca A.; Gest, Scott D.; Rodkin, Philip C.

    2012-01-01

    This study contributes to a growing body of literature focused on the role of the teacher's "invisible hand" in managing students social relationships. The authors focus on one specific aspect of attunement, teachers' social network knowledge, which they conceptualize as the completeness and accuracy of the teacher's social network…

  14. 76 FR 9268 - Financial Crimes Enforcement Network; Imposition of Special Measure Against the Lebanese Canadian...

    Science.gov (United States)

    2011-02-17

    ... Money Laundering Concern AGENCY: Financial Crimes Enforcement Network, Treasury (``FinCEN''), Treasury... financial institution of primary money laundering concern pursuant to 31 U.S.C. 5318A. FinCEN is issuing... Law 107-56. Title III of the USA PATRIOT Act amended the anti- money laundering provisions of the Bank...

  15. Solar ultraviolet radiation in Australia. Results from network measurements and their use in public education

    International Nuclear Information System (INIS)

    Roy, C.R.; Gies, H.P.; Lokan, K.H.

    1993-01-01

    Growing evidence of global depletion of stratospheric ozone has given additional support to the ultraviolet radiation (UVR) network established by ARL in Australia and Antarctica. The data produced is necessary to increase our knowledge of atmospheric change, human health studies and for public education. (4 figs., 1 tab.)

  16. CytoViz: an artistic mapping of network measurements as living organisms in a VR application

    Science.gov (United States)

    López Silva, Brenda A.; Renambot, Luc

    2007-02-01

    CytoViz is an artistic, real-time information visualization driven by statistical information gathered during gigabit network transfers to the Scalable Adaptive Graphical Environment (SAGE) at various events. Data streams are mapped to cellular organisms defining their structure and behavior as autonomous agents. Network bandwidth drives the growth of each entity and the latency defines its physics-based independent movements. The collection of entity is bound within the 3D representation of the local venue. This visual and animated metaphor allows the public to experience the complexity of high-speed network streams that are used in the scientific community. Moreover, CytoViz displays the presence of discoverable Bluetooth devices carried by nearby persons. The concept is to generate an event-specific, real-time visualization that creates informational 3D patterns based on actual local presence. The observed Bluetooth traffic is put in opposition of the wide-area networking traffic by overlaying 2D animations on top of the 3D world. Each device is mapped to an animation fading over time while displaying the name of the detected device and its unique physical address. CytoViz was publicly presented at two major international conferences in 2005 (iGrid2005 in San Diego, CA and SC05 in Seattle, WA).

  17. Measuring the Influence of Information Networks on Transaction Costs Using a Non-parametric Regression Technique

    DEFF Research Database (Denmark)

    Henningsen, Geraldine; Henningsen, Arne; Henning, Christian

    2011-01-01

    to nonpublic information. Our analysis shows that information networks have an impact on the level of TAC. Many resources that are sacrificed for TAC are inputs that also enter the technical production process. As most production data do not separate between these two usages of inputs, high transaction costs...

  18. Networks of gel-forming triblock copolymer solutions: In situ SANS and rheological measurements

    DEFF Research Database (Denmark)

    Mortensen, K.; Almdal, K.; Kleppinger, R.

    1998-01-01

    Triblock copolymers in a solvent, selective for their middle blocks provide the basis for the formation of novel physical networks where cross-links are formed by self-assembled domains of the end-blocks. Triblock copolymers of poly(styrene)-poly(ethylene,butylene)-poly(styrene) (SEBS) dissolved...

  19. Measuring young children's perceptions of support, control, and maintenance in their own social networks

    NARCIS (Netherlands)

    Boosman, K.P.A.; Van der Meulen, Matty; Van Geert, P. L. C.; Jackson, A.E.

    2002-01-01

    Thirty-eight children (aged 3;7-7;6) and one of their parents took part in a study concerning children perceptions of their social networks. The study made use of a newly developed instrument-the Support, Control and Maintenance Pictures Interview (SCAMPI). The SCAMPI offers an individualized

  20. Overview of gas flux measurements from volcanoes of the global Network for Observation of Volcanic and Atmospheric Change (NOVAC)

    Science.gov (United States)

    Galle, Bo; Arellano, Santiago; Conde, Vladimir

    2015-04-01

    NOVAC, the Network for Observation of Volcanic and Atmospheric Change, was initiated in 2005 as a 5-years-long project financed by the European Union. Its main purpose is to create a global network for the study of volcanic atmospheric plumes and related geophysical phenomena by using state-of-the-art spectroscopic remote sensing technology. Up to 2014, 67 instruments have been installed at 25 volcanoes in 13 countries of Latin America, Italy, Democratic Republic of Congo, Reunion, Iceland, and Philippines, and efforts are being done to expand the network to other active volcanic zones. NOVAC has been a pioneer initiative in the community of volcanologists and embraces the objectives of the Word Organization of Volcano Observatories (WOVO) and the Global Earth Observation System of Systems (GEOSS). In this contribution, we present the results of the measurements of SO2 gas fluxes carried out within NOVAC, which for some volcanoes represent a record of more than 8 years of semi-continuous monitoring. The network comprises some of the most strongly degassing volcanoes in the world, covering a broad range of tectonic settings, levels of unrest, and potential risk. Examples of correlations with seismicity and other geophysical phenomena, environmental impact studies and comparisons with previous global estimates will be discussed as well as the significance of the database for further studies in volcanology and other geosciences.

  1. Inventory of gas flux measurements from volcanoes of the global Network for Observation of Volcanic and Atmospheric Change (NOVAC)

    Science.gov (United States)

    Galle, B.; Arellano, S.; Norman, P.; Conde, V.

    2012-04-01

    NOVAC, the Network for Observation of Volcanic and Atmospheric Change, was initiated in 2005 as a 5-year-long project financed by the European Union. Its main purpose is to create a global network for the monitoring and research of volcanic atmospheric plumes and related geophysical phenomena by using state-of-the-art spectroscopic remote sensing technology. Up to 2012, 64 instruments have been installed at 24 volcanoes in 13 countries of Latin America, Italy, Democratic Republic of Congo, Reunion, Iceland, and Philippines, and efforts are being done to expand the network to other active volcanic zones. NOVAC has been a pioneer initiative in the community of volcanologists and embraces the objectives of the Word Organization of Volcano Observatories (WOVO) and the Global Earth Observation System of Systems (GEOSS). In this contribution, we present the results of the measurements of SO2 gas fluxes carried out within NOVAC, which for some volcanoes represent a record of more than 7 years of continuous monitoring. The network comprises some of the most strongly degassing volcanoes in the world, covering a broad range of tectonic settings, levels of unrest, and potential risk. We show a global perspective of the output of volcanic gas from the covered regions, specific trends of degassing for a few selected volcanoes, and the significance of the database for further studies in volcanology and other geosciences.

  2. Measurement of Dielectric Properties at 75 - 325 GHz using a Vector Network Analyzer and Full Wave Simulator

    Directory of Open Access Journals (Sweden)

    S.Khanal

    2012-06-01

    Full Text Available This paper presents a fast and easy to use method to determine permittivity and loss tangent in the frequency range of 75 to 325 GHz. To obtain the permittivity and the loss tangent of the test material, the reflection and transmission S-parameters of a waveguide section filled with the test material are measured using a vector network analyzer and then compared with the simulated plots from a full wave simulator (HFSS, or alternatively the measurement results are used in mathematical formulas. The results are coherent over multiple waveguide bands.

  3. Network performance measurements as part of feasibility studies on moving an ATLAS event filter to off-site institutes

    CERN Document Server

    Korcyl, K; Dobinson, Robert W; Ivanovici, M; Losada-Maia, Marcia; Meirosu, C; Sladowski, G

    2004-01-01

    We present a system for measuring network performance as part of the feasibility studies for locating the ATLAS third level trigger, the event filter (EF), in remote locations. Part of the processing power required to run the EF algorithms, the current estimate is 2000 state off the art processors, can be provided in remote, CERN-affiliated institutes, if a suitable network connection between CERN and the remote site could be achieved. The system is composed of two PCs equipped with GPS systems, CERN-designed clock cards and Alteon gigabit programmable network interface cards. In the first set of measurements we plan to quantify connection in terms of end-to-end latency, throughput, jitter and packet loss. Running streaming tests and study throughput, IP QoS, routing testing and traffic shaping follows this. Finally, we plan to install the event filter software in a remote location and feed it with data from test beams at CERN. Each of these tests should be preformed with the test traffic treated in the netwo...

  4. Structural health monitoring and damage assessment using measured FRFs from multiple sensors. Part II. Decision making with RBF networks

    Energy Technology Data Exchange (ETDEWEB)

    Zang, C.; Friswell, M.I. [Dept. of Aerospace Engineering, Univ. of Bristol, Bristol (United Kingdom); Imregun, M. [Dept. of Mechanical Engineering, Imperial Coll., London (United Kingdom)

    2003-07-01

    This paper is the second of two papers concerned with structural health monitoring and damage assessment using measured FRFs from multiple sensors, and discusses the decision making technique with radial basis function (RBF) neural networks. In PART 1 of the paper, the correlation criteria showed their capability to indicate various changes to the structure's state. PART 2, presented here, develops the methodology of decision theory to identify precisely all of the structure states. Although, the statistical approach can be used for classification, interpreting the information is difficult. Neural network techniques have been proven to possess many advantages for classification due to their learning ability and good generalization. In this paper, the radial basis function neural network is applied for function approximation and recognition. The key idea is to partition the input space (the indicators of the correlation criteria) into a number of subspaces that are in the form of hyper spheres. Then, the widely used k-mean clustering algorithm was selected as a logical approach to detecting the structure states. A bookshelf structure with measured frequency responses from 24 accelerometers was used to demonstrate the effectiveness of the method. The results show the successful classification of all structure states, for instance, the undamaged and damage states, damage locations and damage levels, and the environmental variability. (orig.)

  5. Decreased functional connectivity in schizophrenia: The relationship between social functioning, social cognition and graph theoretical network measures.

    Science.gov (United States)

    Erdeniz, Burak; Serin, Emin; İbadi, Yelda; Taş, Cumhur

    2017-12-30

    Schizophrenia is a complex disorder in which abnormalities in brain connectivity and social functioning play a central role. The aim of this study is to explore small-world network properties, and understand their relationship with social functioning and social cognition in the context of schizophrenia, by testing functional connectivity differences in network properties and its relation to clinical behavioral measures. Resting-state fMRI time series data were acquired from 23 patients diagnosed with schizophrenia and 23 healthy volunteers. The results revealed that patients with schizophrenia show significantly decreased connectivity between a range of brain regions, particularly involving connections among the right orbitofrontal cortex, bilateral putamen and left amygdala. Furthermore, topological properties of functional brain networks in patients with schizophrenia were characterized by reduced path length compared to healthy controls; however, no significant difference was found for clustering coefficient, local efficiency or global efficiency. Additionally, we found that nodal efficiency of the amygdala and the putamen were significantly correlated with the independence-performance subscale of social functioning scale (SFC), and Reading the Mind in the Eyes test; however, the correlations do not survive correction for multiple comparison. The current results help to clarify the relationship between social functioning deficits and topological brain measures in schizophrenia. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Search for transient ultralight dark matter signatures with networks of precision measurement devices using a Bayesian statistics method

    Science.gov (United States)

    Roberts, B. M.; Blewitt, G.; Dailey, C.; Derevianko, A.

    2018-04-01

    We analyze the prospects of employing a distributed global network of precision measurement devices as a dark matter and exotic physics observatory. In particular, we consider the atomic clocks of the global positioning system (GPS), consisting of a constellation of 32 medium-Earth orbit satellites equipped with either Cs or Rb microwave clocks and a number of Earth-based receiver stations, some of which employ highly-stable H-maser atomic clocks. High-accuracy timing data is available for almost two decades. By analyzing the satellite and terrestrial atomic clock data, it is possible to search for transient signatures of exotic physics, such as "clumpy" dark matter and dark energy, effectively transforming the GPS constellation into a 50 000 km aperture sensor array. Here we characterize the noise of the GPS satellite atomic clocks, describe the search method based on Bayesian statistics, and test the method using simulated clock data. We present the projected discovery reach using our method, and demonstrate that it can surpass the existing constrains by several order of magnitude for certain models. Our method is not limited in scope to GPS or atomic clock networks, and can also be applied to other networks of precision measurement devices.

  7. Glass Transition Temperature Measurement for Undercured Cyanate Ester Networks: Challenges, Tips, and Tricks (Briefing Charts)

    Science.gov (United States)

    2014-01-29

    DISTRIBUTION A: Approved for public release; distribution is unlimited. Thermosetting Polymers Have a TG Envelope – Not Just a TG 4 • The glass transition...glass transition temperature of a thermosetting polymer can vary over a wide range of temperatures depending on how the polymer is processed • A... thermosetting polymer with only one kind of network formation and negligible side reactions, the conversion may be determined at every point in the scan. • By

  8. Uncertainty measurement with belief entropy on interference effect in Quantum-Like Bayesian Networks

    OpenAIRE

    Huang, Zhiming; Yang, Lin; Jiang, Wen

    2017-01-01

    Social dilemmas have been regarded as the essence of evolution game theory, in which the prisoner's dilemma game is the most famous metaphor for the problem of cooperation. Recent findings revealed people's behavior violated the Sure Thing Principle in such games. Classic probability methodologies have difficulty explaining the underlying mechanisms of people's behavior. In this paper, a novel quantum-like Bayesian Network was proposed to accommodate the paradoxical phenomenon. The special ne...

  9. Measurement of repeat effects in Chicago’s criminal social network

    Directory of Open Access Journals (Sweden)

    Paul Kump

    2016-07-01

    Full Text Available The “near-repeat” effect is a well-known criminological phenomenon in which the occurrence of a crime incident gives rise to a temporary elevation of crime risk within close physical proximity to an initial incident. Adopting a social network perspective, we instead define a near repeat in terms of geodesic distance within a criminal social network, rather than spatial distance. Specifically, we report a statistical analysis of repeat effects in arrest data for Chicago during the years 2003–2012. We divide the arrest data into two sets (violent crimes and other crimes and, for each set, we compare the distributions of time intervals between repeat incidents to theoretical distributions in which repeat incidents occur only by chance. We first consider the case of the same arrestee participating in repeat incidents (“exact repeats” and then extend the analysis to evaluate repeat risks of those arrestees near one another in the social network. We observe repeat effects that diminish as a function of geodesic distance and time interval, and we estimate typical time scales for repeat crimes in Chicago.

  10. So ware-Defined Network Solutions for Science Scenarios: Performance Testing Framework and Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Settlemyer, Bradley [Los Alamos National Laboratory (LANL); Kettimuthu, R. [Argonne National Laboratory (ANL); Boley, Josh [Argonne National Laboratory (ANL); Katramatos, Dimitrios [Brookhaven National Laboratory (BNL); Rao, Nageswara S. [ORNL; Sen, Satyabrata [ORNL; Liu, Qiang [ORNL

    2018-01-01

    High-performance scientific work flows utilize supercomputers, scientific instruments, and large storage systems. Their executions require fast setup of a small number of dedicated network connections across the geographically distributed facility sites. We present Software-Defined Network (SDN) solutions consisting of site daemons that use dpctl, Floodlight, ONOS, or OpenDaylight controllers to set up these connections. The development of these SDN solutions could be quite disruptive to the infrastructure, while requiring a close coordination among multiple sites; in addition, the large number of possible controller and device combinations to investigate could make the infrastructure unavailable to regular users for extended periods of time. In response, we develop a Virtual Science Network Environment (VSNE) using virtual machines, Mininet, and custom scripts that support the development, testing, and evaluation of SDN solutions, without the constraints and expenses of multi-site physical infrastructures; furthermore, the chosen solutions can be directly transferred to production deployments. By complementing VSNE with a physical testbed, we conduct targeted performance tests of various SDN solutions to help choose the best candidates. In addition, we propose a switching response method to assess the setup times and throughput performances of different SDN solutions, and present experimental results that show their advantages and limitations.

  11. Twenty years of measurement of polycyclic aromatic hydrocarbons (PAHs) in UK ambient air by nationwide air quality networks.

    Science.gov (United States)

    Brown, Andrew S; Brown, Richard J C; Coleman, Peter J; Conolly, Christopher; Sweetman, Andrew J; Jones, Kevin C; Butterfield, David M; Sarantaridis, Dimitris; Donovan, Brian J; Roberts, Ian

    2013-06-01

    The impact of human activities on the health of the population and of the wider environment has prompted action to monitor the presence of toxic compounds in the atmosphere. Toxic organic micropollutants (TOMPs) are some of the most insidious and persistent of these pollutants. Since 1991 the United Kingdom has operated nationwide air quality networks to assess the presence of TOMPs, including polycyclic aromatic hydrocarbons (PAHs), in ambient air. The data produced in 2010 marked 20 years of nationwide PAH monitoring. This paper marks this milestone by providing a novel and critical review of the data produced since nationwide monitoring began up to the end of 2011 (the latest year for which published data is available), discussing how the networks performing this monitoring has evolved, and elucidating trends in the concentrations of the PAHs measured. The current challenges in the area and a forward look to the future of air quality monitoring for PAHs are also discussed briefly.

  12. Establishing a Network of Citizen Scientists to Measure Trans-Neptunian Objects (Invited)

    Science.gov (United States)

    Keller, J. M.; Buie, M. W.

    2013-12-01

    The Research and Education Cooperative Occultation Network (RECON) is an innovative citizen science project to determine the sizes of trans-Neptunian objects (TNOs) and in particular cold classical Kuiper Belt Objects (KBOs). The project currently involves a pilot network of fourteen communities located north and south of Reno, Nevada (from Tulelake, CA to Tonopah, NV) that have been provided with telescope and camera equipment to record occultation data when TNOs and main belt asteroids pass in front of background stars. Current uncertainties in TNO positions and stellar astrometry limit accurate occultation predictions for TNOs. To address this challenge, RECON will establish a 'picket-fence' of observers every 50 km spread over a 2,000-km baseline. When fully scaled, RECON will involve over forty communities stretching across the Western United States from its border with Canada to Mexico. See map for current telescope sites (green and yellow), planned telescope sites (blue), and shadow path for a 100 km object. The pilot RECON network has been established as a proof-of-concept study for this project. Teachers, amateur astronomers, and community members from California and Nevada were recruited via emails, phone, and face-to-face visits during two trips in Fall 2012. Telescope and camera equipment was tested and delivered to each community in Winter 2013. In April, representatives from each community brought this equipment to a four-day intensive training workshop in Carson City. Since the workshop, RECON has conducted five coordinated occultation campaigns involving Pluto and several main belt asteroids to demonstrate the effectiveness and integrity of the network. In addition to presenting results from these observation campaigns, we will describe lessons learned about recruitment, preparation, and retention of citizen scientists from rural communities to conduct authentic astronomy research. We will also discuss plans for scaling up the full RECON network

  13. Discrete event simulation methods applied to advanced importance measures of repairable components in multistate network flow systems

    International Nuclear Information System (INIS)

    Huseby, Arne B.; Natvig, Bent

    2013-01-01

    Discrete event models are frequently used in simulation studies to model and analyze pure jump processes. A discrete event model can be viewed as a system consisting of a collection of stochastic processes, where the states of the individual processes change as results of various kinds of events occurring at random points of time. We always assume that each event only affects one of the processes. Between these events the states of the processes are considered to be constant. In the present paper we use discrete event simulation in order to analyze a multistate network flow system of repairable components. In order to study how the different components contribute to the system, it is necessary to describe the often complicated interaction between component processes and processes at the system level. While analytical considerations may throw some light on this, a simulation study often allows the analyst to explore more details. By producing stable curve estimates for the development of the various processes, one gets a much better insight in how such systems develop over time. These methods are particulary useful in the study of advanced importancez measures of repairable components. Such measures can be very complicated, and thus impossible to calculate analytically. By using discrete event simulations, however, this can be done in a very natural and intuitive way. In particular significant differences between the Barlow–Proschan measure and the Natvig measure in multistate network flow systems can be explored

  14. Development of indirect measures of conscientiousness : combining a facets approach and network analysis

    NARCIS (Netherlands)

    Costantini, G.; Richetin, J.; Borsboom, D.; Fried, E.I.; Rhemtulla, M.; Perugini, M.

    2015-01-01

    Because indirect measures of personality self-concepts such as the Implicit Association Test (IAT) allow tapping into automatic processes, they can offer advantages over self-report measures. However, prior investigations have led to mixed results regarding the validity of indirect measures of

  15. Measuring the Influence of Networks on Transaction Costs Using a Nonparametric Regression Technique

    DEFF Research Database (Denmark)

    Henningsen, Geraldine; Henningsen, Arne; Henning, Christian H.C.A.

    All business transactions as well as achieving innovations take up resources, subsumed under the concept of transaction costs. One of the major factors in transaction costs theory is information. Firm networks can catalyse the interpersonal information exchange and hence, increase the access to non......-public information so that transaction costs are reduced.Many resources that are sacrificed for transaction costs are inputs that also enter the technical production process. As most production data do not distinguish between these two usages of inputs, high transaction costs result in reduced observed productivity...

  16. Measuring the influence of networks on transaction costs using a non-parametric regression technique

    DEFF Research Database (Denmark)

    Henningsen, Géraldine; Henningsen, Arne; Henning, Christian H.C.A.

    All business transactions as well as achieving innovations take up resources, subsumed under the concept of transaction costs. One of the major factors in transaction costs theory is information. Firm networks can catalyse the interpersonal information exchange and hence, increase the access to non......-public information so that transaction costs are reduced. Many resources that are sacrificed for transaction costs are inputs that also enter the technical production process. As most production data do not distinguish between these two usages of inputs, high transaction costs result in reduced observed productivity...

  17. Measurement and Internalization of Systemic Risk in a Global Banking Network

    Science.gov (United States)

    Feng, Xiaobing; Hu, Haibo

    2013-12-01

    The negative externalities from an individual bank failure to the whole system can be huge. One of the key purposes of bank regulation is to internalize the social costs of potential bank failures via capital charges. This study proposes a method to evaluate and allocate the systemic risk to different countries/regions using a Susceptible-Infected-Removable (SIR) type of epidemic spreading model and the Shapley value (SV) in game theory. The paper also explores features of a constructed bank network using real globe-wide banking data.

  18. Citizen-Enabled Aerosol Measurements for Satellites (CEAMS): A Network for High-Resolution Measurements of PM2.5 and Aerosol Optical Depth

    Science.gov (United States)

    Pierce, J. R.; Volckens, J.; Ford, B.; Jathar, S.; Long, M.; Quinn, C.; Van Zyl, L.; Wendt, E.

    2017-12-01

    Atmospheric particulate matter with diameter smaller than 2.5 μm (PM2.5) is a pollutant that contributes to the development of human disease. Satellite-derived estimates of surface-level PM2.5 concentrations have the potential to contribute greatly to our understanding of how particulate matter affects health globally. However, these satellite-derived PM2.5 estimates are often uncertain due to a lack of information about the ratio of surface PM2.5 to aerosol optical depth (AOD), which is the primary aerosol retrieval made by satellite instruments. While modelling and statistical analyses have improved estimates of PM2.5:AOD, large uncertainties remain in situations of high PM2.5 exposure (such as urban areas and in wildfire-smoke plumes) where the health impacts of PM2.5 may be the greatest. Surface monitoring networks for co-incident PM2.5 and AOD measurements are extremely rare, even in the North America. To provide constraints for the PM2.5:AOD relationship, we have developed a relatively low-cost (application (iOS and Android). Sun photometry is performed across 4 discrete wavelengths that match those reported by the Aerosol Robotic Network (AERONET). Aerosol concentration is reported using both time-integrated filter mass (analyzed in an academic laboratory and reported as a 24-48hr average) and a continuous PM sensor within the instrument. Citizen scientists use the device to report daily AOD and PM2.5 measurements made in their backyards to a central server for data display and download. In this presentation, we provide an overview of (1) AOD and PM2.5 measurement calibration; (2) citizen recruiting and training efforts; and (3) results from our pilot citizen-science measurement campaign.

  19. Sensor Networks for Optimal Target Localization with Bearings-Only Measurements in Constrained Three-Dimensional Scenarios

    Directory of Open Access Journals (Sweden)

    Joaquin Aranda

    2013-08-01

    Full Text Available In this paper, we address the problem of determining the optimal geometric configuration of an acoustic sensor network that will maximize the angle-related information available for underwater target positioning. In the set-up adopted, a set of autonomous vehicles carries a network of acoustic units that measure the elevation and azimuth angles between a target and each of the receivers on board the vehicles. It is assumed that the angle measurements are corrupted by white Gaussian noise, the variance of which is distance-dependent. Using tools from estimation theory, the problem is converted into that of minimizing, by proper choice of the sensor positions, the trace of the inverse of the Fisher Information Matrix (also called the Cramer-Rao Bound matrix to determine the sensor configuration that yields the minimum possible covariance of any unbiased target estimator. It is shown that the optimal configuration of the sensors depends explicitly on the intensity of the measurement noise, the constraints imposed on the sensor configuration, the target depth and the probabilistic distribution that defines the prior uncertainty in the target position. Simulation examples illustrate the key results derived.

  20. Sensor networks for optimal target localization with bearings-only measurements in constrained three-dimensional scenarios.

    Science.gov (United States)

    Moreno-Salinas, David; Pascoal, Antonio; Aranda, Joaquin

    2013-08-12

    In this paper, we address the problem of determining the optimal geometric configuration of an acoustic sensor network that will maximize the angle-related information available for underwater target positioning. In the set-up adopted, a set of autonomous vehicles carries a network of acoustic units that measure the elevation and azimuth angles between a target and each of the receivers on board the vehicles. It is assumed that the angle measurements are corrupted by white Gaussian noise, the variance of which is distance-dependent. Using tools from estimation theory, the problem is converted into that of minimizing, by proper choice of the sensor positions, the trace of the inverse of the Fisher Information Matrix (also called the Cramer-Rao Bound matrix) to determine the sensor configuration that yields the minimum possible covariance of any unbiased target estimator. It is shown that the optimal configuration of the sensors depends explicitly on the intensity of the measurement noise, the constraints imposed on the sensor configuration, the target depth and the probabilistic distribution that defines the prior uncertainty in the target position. Simulation examples illustrate the key results derived.

  1. Vulnerability of complex networks

    Science.gov (United States)

    Mishkovski, Igor; Biey, Mario; Kocarev, Ljupco

    2011-01-01

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

  2. Engineering survey planning for the alignment of a particle accelerator: part II. Design of a reference network and measurement strategy

    Science.gov (United States)

    Junqueira Leão, Rodrigo; Raffaelo Baldo, Crhistian; Collucci da Costa Reis, Maria Luisa; Alves Trabanco, Jorge Luiz

    2018-03-01

    The building blocks of particle accelerators are magnets responsible for keeping beams of charged particles at a desired trajectory. Magnets are commonly grouped in support structures named girders, which are mounted on vertical and horizontal stages. The performance of this type of machine is highly dependent on the relative alignment between its main components. The length of particle accelerators ranges from small machines to large-scale national or international facilities, with typical lengths of hundreds of meters to a few kilometers. This relatively large volume together with micrometric positioning tolerances make the alignment activity a classical large-scale dimensional metrology problem. The alignment concept relies on networks of fixed monuments installed on the building structure to which all accelerator components are referred. In this work, the Sirius accelerator is taken as a case study, and an alignment network is optimized via computational methods in terms of geometry, densification, and surveying procedure. Laser trackers are employed to guide the installation and measure the girders’ positions, using the optimized network as a reference and applying the metric developed in part I of this paper. Simulations demonstrate the feasibility of aligning the 220 girders of the Sirius synchrotron to better than 0.080 mm, at a coverage probability of 95%.

  3. Robust Sequential Covariance Intersection Fusion Kalman Filtering over Multi-agent Sensor Networks with Measurement Delays and Uncertain Noise Variances

    Institute of Scientific and Technical Information of China (English)

    QI Wen-Juan; ZHANG Peng; DENG Zi-Li

    2014-01-01

    This paper deals with the problem of designing robust sequential covariance intersection (SCI) fusion Kalman filter for the clustering multi-agent sensor network system with measurement delays and uncertain noise variances. The sensor network is partitioned into clusters by the nearest neighbor rule. Using the minimax robust estimation principle, based on the worst-case conservative sensor network system with conservative upper bounds of noise variances, and applying the unbiased linear minimum variance (ULMV) optimal estimation rule, we present the two-layer SCI fusion robust steady-state Kalman filter which can reduce communication and computation burdens and save energy sources, and guarantee that the actual filtering error variances have a less-conservative upper-bound. A Lyapunov equation method for robustness analysis is proposed, by which the robustness of the local and fused Kalman filters is proved. The concept of the robust accuracy is presented and the robust accuracy relations of the local and fused robust Kalman filters are proved. It is proved that the robust accuracy of the global SCI fuser is higher than those of the local SCI fusers and the robust accuracies of all SCI fusers are higher than that of each local robust Kalman filter. A simulation example for a tracking system verifies the robustness and robust accuracy relations.

  4. A Study of the Deformation, Network, and Aging of Polyethylene Oxide Films by Infrared Spectroscopy and Calorimetric Measurements

    Directory of Open Access Journals (Sweden)

    Carl Bergeron

    2012-01-01

    Full Text Available The calorimetric and infrared (IR spectroscopy measurements of polyethylene oxide (PEO are used to evaluate the deformation and relaxation that films experience during a temperature cycle (30°C–90°C–30°C. After melting, the intensity of some bands decreases by 10 to 70%. During the temperature cycle, the C–O band in the 1100 cm−1 region and the C–C–O deformation bands at 650 and 500 cm−1 show some new features. A network of cooperative oxygen-hydrogen interactions between the PEO chains form in films with special history, namely, in thermally treated films, in thin films prepared from gel forming solutions, and in thick films after aging. The interchain interaction network is suggested from the IR absorption bands in the 1200 and 900 cm−1 region and also from small bands at 1144 and 956 cm−1. The network seems absent or reduced in thin films. IR spectroscopy appears a sensitive technique to study chain conformations in PEO films and in other materials where order, disorder, and the formation of intermolecular interactions coexist.

  5. A neural network detection system for lower-hybrid cavities in electron plasma density measured by the FREJA satellite

    International Nuclear Information System (INIS)

    Waldemark, J.; Karlsson, Jan

    1995-03-01

    This paper presents a lower-hybrid cavity detection system, CDS, for measurements of electron plasma density on the FREJA satellite wave experiment. The system can reduce the amount of data to be analysed by as much as 96% and still retain more than 85% of the desired information. The CDS is a combination of a hybrid neural network, HNN and expert rules. The HNN is a Self Organizing Map, SOM, combined with a feed forward back propagation neural net, BP. The CDS can be controlled by the user to operate with various degrees of sensitivity. Maximum detection capability is as high as 95% with data reduction lowered to 85%. 10 refs

  6. Effects of Creatine Monohydrate Augmentation on Brain Metabolic and Network Outcome Measures in Women With Major Depressive Disorder.

    Science.gov (United States)

    Yoon, Sujung; Kim, Jieun E; Hwang, Jaeuk; Kim, Tae-Suk; Kang, Hee Jin; Namgung, Eun; Ban, Soonhyun; Oh, Subin; Yang, Jeongwon; Renshaw, Perry F; Lyoo, In Kyoon

    2016-09-15

    Creatine monohydrate (creatine) augmentation has the potential to accelerate the clinical responses to and enhance the overall efficacy of selective serotonin reuptake inhibitor treatment in women with major depressive disorder (MDD). Although it has been suggested that creatine augmentation may involve the restoration of brain energy metabolism, the mechanisms underlying its antidepressant efficacy are unknown. In a randomized, double-blind, placebo-controlled trial, 52 women with MDD were assigned to receive either creatine augmentation or placebo augmentation of escitalopram; 34 subjects participated in multimodal neuroimaging assessments at baseline and week 8. Age-matched healthy women (n = 39) were also assessed twice at the same intervals. Metabolic and network outcomes were measured for changes in prefrontal N-acetylaspartate and changes in rich club hub connections of the structural brain network using proton magnetic resonance spectroscopy and diffusion tensor imaging, respectively. We found MDD-related metabolic and network dysfunction at baseline. Improvement in depressive symptoms was greater in patients receiving creatine augmentation relative to placebo augmentation. After 8 weeks of treatment, prefrontal N-acetylaspartate levels increased significantly in the creatine augmentation group compared with the placebo augmentation group. Increment in rich club hub connections was also greater in the creatine augmentation group than in the placebo augmentation group. N-acetylaspartate levels and rich club connections increased after creatine augmentation of selective serotonin reuptake inhibitor treatment. Effects of creatine administration on brain energy metabolism and network organization may partly underlie its efficacy in treating women with MDD. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  7. Concept mapping and network analysis: an analytic approach to measure ties among constructs.

    Science.gov (United States)

    Goldman, Alyssa W; Kane, Mary

    2014-12-01

    Group concept mapping is a mixed-methods approach that helps a group visually represent its ideas on a topic of interest through a series of related maps. The maps and additional graphics are useful for planning, evaluation and theory development. Group concept maps are typically described, interpreted and utilized through points, clusters and distances, and the implications of these features in understanding how constructs relate to one another. This paper focuses on the application of network analysis to group concept mapping to quantify the strength and directionality of relationships among clusters. The authors outline the steps of this analysis, and illustrate its practical use through an organizational strategic planning example. Additional benefits of this analysis to evaluation projects are also discussed, supporting the overall utility of this supplemental technique to the standard concept mapping methodology. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Development of Tools for Simulation Systems in a Distribution Network and Validated by Measurements

    DEFF Research Database (Denmark)

    Mihet-Popa, Lucian; Koch-Ciobotaru, C.; Isleifsson, Fridrik Rafn

    2012-01-01

    The increasing amount of DER components into distribution networks involves the development of accurate simulation models that take into account an increasing number of factors that influence the output power from the DG systems. This paper presents two simulation models: a PV panel model using....../Simulink, has also been developed and implemented in PowerFactory to study load flow, steadystate voltage stability and dynamic behavior of a distribution power system....... the single-diode four-parameter model based on data sheet values and a VRB system model based on the efficiency of different components and the power losses. The models were implemented first in MATLAB/Simulink and the results have been compared with the data sheet values and with the characteristics...

  9. Comparative Analysis of Performance Measures for Network Screening: A Case Study of Brazilian Urban Areas

    Directory of Open Access Journals (Sweden)

    Vanessa Jamille Mesquita Xavier

    2017-01-01

    Full Text Available The overall effectiveness of the roadway safety management process relies on a robust method for identifying and ranking sites with major potential for safety improvements. In Brazil, guidelines for hotspot identification are usually based only on crash frequency and Crash Rate as safety performance measures. This study presents a comparative analysis of safety performance measures, considering its limitations of applicability in a sample of signalized intersections from Fortaleza city, Brazil. The performance of each measure to rank the sample intersection was obtained through the rank difference between each safety performance measure and the Excess Expected Average Crash Frequency with EB Adjustment (EEB. In addition, it has taken a temporal analysis based on the consistency of safety performance measures during subsequent time periods. The results have suggested a reasonable matching between the most comprehensive safety performance measure (EEB and very simple safety performance measures such as crash frequency and Crash Rate. It is recommended to investigate the consistency of the results for longer observation period as well as for a different jurisdiction in Brazil.

  10. Validation of SCIAMACHY HDO/H2O measurements using the TCCON and NDACC-MUSICA networks

    Science.gov (United States)

    Scheepmaker, R. A.; Frankenberg, C.; Deutscher, N. M.; Schneider, M.; Barthlott, S.; Blumenstock, T.; Garcia, O. E.; Hase, F.; Jones, N.; Mahieu, E.; Notholt, J.; Velazco, V.; Landgraf, J.; Aben, I.

    2015-04-01

    Measurements of the atmospheric HDO/H2O ratio help us to better understand the hydrological cycle and improve models to correctly simulate tropospheric humidity and therefore climate change. We present an updated version of the column-averaged HDO/H2O ratio data set from the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY). The data set is extended with 2 additional years, now covering 2003-2007, and is validated against co-located ground-based total column δD measurements from Fourier transform spectrometers (FTS) of the Total Carbon Column Observing Network (TCCON) and the Network for the Detection of Atmospheric Composition Change (NDACC, produced within the framework of the MUSICA project). Even though the time overlap among the available data is not yet ideal, we determined a mean negative bias in SCIAMACHY δD of -35 ± 30‰ compared to TCCON and -69 ± 15‰ compared to MUSICA (the uncertainty indicating the station-to-station standard deviation). The bias shows a latitudinal dependency, being largest (∼ -60 to -80‰) at the highest latitudes and smallest (∼ -20 to -30‰) at the lowest latitudes. We have tested the impact of an offset correction to the SCIAMACHY HDO and H2O columns. This correction leads to a humidity- and latitude-dependent shift in δD and an improvement of the bias by 27‰, although it does not lead to an improved correlation with the FTS measurements nor to a strong reduction of the latitudinal dependency of the bias. The correction might be an improvement for dry, high-altitude areas, such as the Tibetan Plateau and the Andes region. For these areas, however, validation is currently impossible due to a lack of ground stations. The mean standard deviation of single-sounding SCIAMACHY-FTS differences is ∼ 115‰, which is reduced by a factor ∼ 2 when we consider monthly means. When we relax the strict matching of individual measurements and focus on the mean seasonalities using all available

  11. Digital Earth Watch And Picture Post Network: Measuring The Environment Through Digital Images

    Science.gov (United States)

    Schloss, A. L.; Beaudry, J.; Carrera, F.; Pickle, J.

    2010-12-01

    Digital Earth Watch (DEW) involves individuals, schools, organizations and communities in a systematic monitoring project of their local environment, especially vegetation health. The program offers people the means to join the Picture Post network and to study and analyze their own findings using DEW software. A Picture Post is an easy-to-use and inexpensive platform for repeatedly taking digital photographs as a standardized set of images of the entire 360 ° landscape, which then can be shared over the Internet on the Picture Post website. This simple concept has the potential to create a wealth of information and data on changing environmental conditions, which is important for a society grappling with the effects of environmental change. Picture Post participants study change over time in their local area, compare digital images with NASA satellite imagery and contribute towards improving their own communities. A key message in DEW is that although plants are dynamic and respond continuously to their environment, they do so either on a time-scale that most people don't notice or with a subtlety our senses can't detect. DEW has created simple tools for monitoring vegetation as a means towards understanding the connection between global climate change and local effects. Picture Posts may be added by anyone interested in monitoring a particular location. The value of a Picture Post is in the commitment of participants to take repeated photographs - monthly, weekly, or even daily - to build up a long-term record over many years. DEW is being developed by a collaborative effort led by the University of New Hampshire with the Federation of Earth Science Information Partners, the University of Southern Maine, and Worcester Polytechnic Institute. This poster will show examples of picture posts and data that can be collected and will describe our soon-to-be-released “ virtual ” picture post cell phone app. The Picture Post network is new and we invite individuals

  12. Measuring temporal stability of positron emission tomography standardized uptake value bias using long-lived sources in a multicenter network.

    Science.gov (United States)

    Byrd, Darrin; Christopfel, Rebecca; Arabasz, Grae; Catana, Ciprian; Karp, Joel; Lodge, Martin A; Laymon, Charles; Moros, Eduardo G; Budzevich, Mikalai; Nehmeh, Sadek; Scheuermann, Joshua; Sunderland, John; Zhang, Jun; Kinahan, Paul

    2018-01-01

    Positron emission tomography (PET) is a quantitative imaging modality, but the computation of standardized uptake values (SUVs) requires several instruments to be correctly calibrated. Variability in the calibration process may lead to unreliable quantitation. Sealed source kits containing traceable amounts of [Formula: see text] were used to measure signal stability for 19 PET scanners at nine hospitals in the National Cancer Institute's Quantitative Imaging Network. Repeated measurements of the sources were performed on PET scanners and in dose calibrators. The measured scanner and dose calibrator signal biases were used to compute the bias in SUVs at multiple time points for each site over a 14-month period. Estimation of absolute SUV accuracy was confounded by bias from the solid phantoms' physical properties. On average, the intrascanner coefficient of variation for SUV measurements was 3.5%. Over the entire length of the study, single-scanner SUV values varied over a range of 11%. Dose calibrator bias was not correlated with scanner bias. Calibration factors from the image metadata were nearly as variable as scanner signal, and were correlated with signal for many scanners. SUVs often showed low intrascanner variability between successive measurements but were also prone to shifts in apparent bias, possibly in part due to scanner recalibrations that are part of regular scanner quality control. Biases of key factors in the computation of SUVs were not correlated and their temporal variations did not cancel out of the computation. Long-lived sources and image metadata may provide a check on the recalibration process.

  13. Creating Actionable Data from an Optical Depth Measurement Network using RDF

    Science.gov (United States)

    Freemantle, J. R.; O'Neill, N. T.; Lumb, L. I.; Abboud, I.; McArthur, B.

    2010-12-01

    The AEROCAN sunphotometery network has, for more than a decade, generated optical indicators of aerosol concentration and size on a regional and national scale. We believe this optical information can be rendered more “actionable” to the health care community by developing a technical and interpretative information-sharing geospatial strategy with that community. By actionable data we mean information that is presented in manner that can be understood and then used in the decision making process. The decision may be that of a technical professional, a policy maker or a machine. The information leading up to a decision may come from many sources; this means it is particularly important that data are well defined across knowledge fields, in our case atmospheric science and respiratory health science. As part of the AEROCAN operational quality assurance (QA) methodology we have written automatic procedures to make some of the AEROCAN data more accessible or “actionable”. Tim Berners-Lee has advocated making datasets, “Linked Data”, available on the web with a proper structural description (metadata). We have been using RDF (Resource Description Framework) to enhance the utility of our sunphotometer data; the resulting self-describing representation is structured so that it is machine readable. This allows semantically based queries (e.g., via SPARQL) on our dataset that in the past were only viewable as passive Web tables of data.

  14. Automated bony region identification using artificial neural networks: reliability and validation measurements

    Energy Technology Data Exchange (ETDEWEB)

    Gassman, Esther E.; Kallemeyn, Nicole A.; DeVries, Nicole A.; Shivanna, Kiran H. [The University of Iowa, Department of Biomedical Engineering, Seamans Center for the Engineering Arts and Sciences, Iowa City, IA (United States); The University of Iowa, Center for Computer-Aided Design, Iowa City, IA (United States); Powell, Stephanie M. [The University of Iowa, Department of Biomedical Engineering, Seamans Center for the Engineering Arts and Sciences, Iowa City, IA (United States); University of Iowa Hospitals and Clinics, The University of Iowa, Department of Radiology, Iowa City, IA (United States); Magnotta, Vincent A. [The University of Iowa, Department of Biomedical Engineering, Seamans Center for the Engineering Arts and Sciences, Iowa City, IA (United States); The University of Iowa, Center for Computer-Aided Design, Iowa City, IA (United States); University of Iowa Hospitals and Clinics, The University of Iowa, Department of Radiology, Iowa City, IA (United States); Ramme, Austin J. [University of Iowa Hospitals and Clinics, The University of Iowa, Department of Radiology, Iowa City, IA (United States); Adams, Brian D. [The University of Iowa, Department of Biomedical Engineering, Seamans Center for the Engineering Arts and Sciences, Iowa City, IA (United States); University of Iowa Hospitals and Clinics, The University of Iowa, Department of Orthopaedics and Rehabilitation, Iowa City, IA (United States); Grosland, Nicole M. [The University of Iowa, Department of Biomedical Engineering, Seamans Center for the Engineering Arts and Sciences, Iowa City, IA (United States); University of Iowa Hospitals and Clinics, The University of Iowa, Department of Orthopaedics and Rehabilitation, Iowa City, IA (United States); The University of Iowa, Center for Computer-Aided Design, Iowa City, IA (United States)

    2008-04-15

    The objective was to develop tools for automating the identification of bony structures, to assess the reliability of this technique against manual raters, and to validate the resulting regions of interest against physical surface scans obtained from the same specimen. Artificial intelligence-based algorithms have been used for image segmentation, specifically artificial neural networks (ANNs). For this study, an ANN was created and trained to identify the phalanges of the human hand. The relative overlap between the ANN and a manual tracer was 0.87, 0.82, and 0.76, for the proximal, middle, and distal index phalanx bones respectively. Compared with the physical surface scans, the ANN-generated surface representations differed on average by 0.35 mm, 0.29 mm, and 0.40 mm for the proximal, middle, and distal phalanges respectively. Furthermore, the ANN proved to segment the structures in less than one-tenth of the time required by a manual rater. The ANN has proven to be a reliable and valid means of segmenting the phalanx bones from CT images. Employing automated methods such as the ANN for segmentation, eliminates the likelihood of rater drift and inter-rater variability. Automated methods also decrease the amount of time and manual effort required to extract the data of interest, thereby making the feasibility of patient-specific modeling a reality. (orig.)

  15. Automated bony region identification using artificial neural networks: reliability and validation measurements

    International Nuclear Information System (INIS)

    Gassman, Esther E.; Kallemeyn, Nicole A.; DeVries, Nicole A.; Shivanna, Kiran H.; Powell, Stephanie M.; Magnotta, Vincent A.; Ramme, Austin J.; Adams, Brian D.; Grosland, Nicole M.

    2008-01-01

    The objective was to develop tools for automating the identification of bony structures, to assess the reliability of this technique against manual raters, and to validate the resulting regions of interest against physical surface scans obtained from the same specimen. Artificial intelligence-based algorithms have been used for image segmentation, specifically artificial neural networks (ANNs). For this study, an ANN was created and trained to identify the phalanges of the human hand. The relative overlap between the ANN and a manual tracer was 0.87, 0.82, and 0.76, for the proximal, middle, and distal index phalanx bones respectively. Compared with the physical surface scans, the ANN-generated surface representations differed on average by 0.35 mm, 0.29 mm, and 0.40 mm for the proximal, middle, and distal phalanges respectively. Furthermore, the ANN proved to segment the structures in less than one-tenth of the time required by a manual rater. The ANN has proven to be a reliable and valid means of segmenting the phalanx bones from CT images. Employing automated methods such as the ANN for segmentation, eliminates the likelihood of rater drift and inter-rater variability. Automated methods also decrease the amount of time and manual effort required to extract the data of interest, thereby making the feasibility of patient-specific modeling a reality. (orig.)

  16. Measurement correction method for force sensor used in dynamic pressure calibration based on artificial neural network optimized by genetic algorithm

    Science.gov (United States)

    Gu, Tingwei; Kong, Deren; Shang, Fei; Chen, Jing

    2017-12-01

    We present an optimization algorithm to obtain low-uncertainty dynamic pressure measurements from a force-transducer-based device. In this paper, the advantages and disadvantages of the methods that are commonly used to measure the propellant powder gas pressure, the applicable scope of dynamic pressure calibration devices, and the shortcomings of the traditional comparison calibration method based on the drop-weight device are firstly analysed in detail. Then, a dynamic calibration method for measuring pressure using a force sensor based on a drop-weight device is introduced. This method can effectively save time when many pressure sensors are calibrated simultaneously and extend the life of expensive reference sensors. However, the force sensor is installed between the drop-weight and the hammerhead by transition pieces through the connection mode of bolt fastening, which causes adverse effects such as additional pretightening and inertia forces. To solve these effects, the influence mechanisms of the pretightening force, the inertia force and other influence factors on the force measurement are theoretically analysed. Then a measurement correction method for the force measurement is proposed based on an artificial neural network optimized by a genetic algorithm. The training and testing data sets are obtained from calibration tests, and the selection criteria for the key parameters of the correction model is discussed. The evaluation results for the test data show that the correction model can effectively improve the force measurement accuracy of the force sensor. Compared with the traditional high-accuracy comparison calibration method, the percentage difference of the impact-force-based measurement is less than 0.6% and the relative uncertainty of the corrected force value is 1.95%, which can meet the requirements of engineering applications.

  17. Estimation of stress distribution in ferromagnetic tensile specimens using low cost eddy current stress measurement system and BP neural network.

    Directory of Open Access Journals (Sweden)

    Jianwei Li

    Full Text Available Estimation of the stress distribution in ferromagnetic components is very important for evaluating the working status of mechanical equipment and implementing preventive maintenance. Eddy current testing technology is a promising method in this field because of its advantages of safety, no need of coupling agent, etc. In order to reduce the cost of eddy current stress measurement system, and obtain the stress distribution in ferromagnetic materials without scanning, a low cost eddy current stress measurement system based on Archimedes spiral planar coil was established, and a method based on BP neural network to obtain the stress distribution using the stress of several discrete test points was proposed. To verify the performance of the developed test system and the validity of the proposed method, experiment was implemented using structural steel (Q235 specimens. Standard curves of sensors at each test point were achieved, the calibrated data were used to establish the BP neural network model for approximating the stress variation on the specimen surface, and the stress distribution curve of the specimen was obtained by interpolating with the established model. The results show that there is a good linear relationship between the change of signal modulus and the stress in most elastic range of the specimen, and the established system can detect the change in stress with a theoretical average sensitivity of -0.4228 mV/MPa. The obtained stress distribution curve is well consonant with the theoretical analysis result. At last, possible causes and improving methods of problems appeared in the results were discussed. This research has important significance for reducing the cost of eddy current stress measurement system, and advancing the engineering application of eddy current stress testing.

  18. Estimation of stress distribution in ferromagnetic tensile specimens using low cost eddy current stress measurement system and BP neural network.

    Science.gov (United States)

    Li, Jianwei; Zhang, Weimin; Zeng, Weiqin; Chen, Guolong; Qiu, Zhongchao; Cao, Xinyuan; Gao, Xuanyi

    2017-01-01

    Estimation of the stress distribution in ferromagnetic components is very important for evaluating the working status of mechanical equipment and implementing preventive maintenance. Eddy current testing technology is a promising method in this field because of its advantages of safety, no need of coupling agent, etc. In order to reduce the cost of eddy current stress measurement system, and obtain the stress distribution in ferromagnetic materials without scanning, a low cost eddy current stress measurement system based on Archimedes spiral planar coil was established, and a method based on BP neural network to obtain the stress distribution using the stress of several discrete test points was proposed. To verify the performance of the developed test system and the validity of the proposed method, experiment was implemented using structural steel (Q235) specimens. Standard curves of sensors at each test point were achieved, the calibrated data were used to establish the BP neural network model for approximating the stress variation on the specimen surface, and the stress distribution curve of the specimen was obtained by interpolating with the established model. The results show that there is a good linear relationship between the change of signal modulus and the stress in most elastic range of the specimen, and the established system can detect the change in stress with a theoretical average sensitivity of -0.4228 mV/MPa. The obtained stress distribution curve is well consonant with the theoretical analysis result. At last, possible causes and improving methods of problems appeared in the results were discussed. This research has important significance for reducing the cost of eddy current stress measurement system, and advancing the engineering application of eddy current stress testing.

  19. Intercomparison of MODIS Albedo Retrievals and In Situ Measurements Across the Global FLUXNET Network

    Science.gov (United States)

    Cescatti, Alessandro; Marcolla, Barbara; Vannan, Suresh K. Santhana; Pan, Jerry Yun; Roman, Miguel O.; Yang, Xiaoyuan; Ciais, Philippe; Cook, Robert B.; Law, Beverly E.; Matteucci, Girogio; hide

    2012-01-01

    Surface albedo is a key parameter in the Earth's energy balance since it affects the amount of solar radiation directly absorbed at the planet surface. Its variability in time and space can be globally retrieved through the use of remote sensing products. To evaluate and improve the quality of satellite retrievals, careful intercomparisons with in situ measurements of surface albedo are crucial. For this purpose we compared MODIS albedo retrievals with surface measurements taken at 53 FLUXNET sites that met strict conditions of land cover homogeneity. A good agreement between mean yearly values of satellite retrievals and in situ measurements was found (R(exp 2)= 0.82). The mismatch is correlated to the spatial heterogeneity of surface albedo, stressing the relevance of land cover homogeneity when comparing point to pixel data. When the seasonal patterns of MODIS albedo is considered for different plant functional types, the match with surface observation is extremely good at all forest sites. On the contrary, in non-forest sites satellite retrievals underestimate in situ measurements across the seasonal cycle. The mismatch observed at grasslands and croplands sites is likely due to the extreme fragmentation of these landscapes, as confirmed by geostatistical attributes derived from high resolution scenes.

  20. Measuring Africa's E-Readiness in the Global Networked Economy: A Nine-Country Data Analysis

    Science.gov (United States)

    Ifinedo, Princely

    2005-01-01

    This paper assesses the integration of Africa into the global economy by computing the e-readiness for nine African countries. The measuring tool used is simple and incorporates a variety of indicators used by comparable tools. Overall, the mean e-readiness of Africa is poor in comparison to other economies. Particularly, Sub-Saharan Africa…